ELECTRIC POWER GENERATION SYSTEM AND RECIPROCATING MECHANISM FOR ELECTRIC POWER GENERATION SYSTEM

Abstract

Provided is an electric power generation system with which, when converting energy of a flowing fluid, an electric power generation mechanism is located at a site different from a site that receives the energy of the flowing fluid, with energy transfer system by outer and inner cable.

Claims

1. An electric power generation system comprising: a fluid receiving mechanism that is disposed in a region that receives a flowing fluid and that performs motion selected from a group consisting of rotational motion and reciprocating motion in accordance with a flow of the fluid; a reciprocating mechanism that is connected to the fluid receiving mechanism and that performs reciprocating motion on the basis of the motion of the fluid receiving mechanism; and an electric power generation mechanism that is disposed in a region different from the region in which the fluid receiving mechanism is disposed and that converts the reciprocating motion of the reciprocating mechanism into electric power, wherein the reciprocating mechanism includes an inner cable and a tubular outer cable; the outer cable is disposed between the fluid receiving mechanism and the electric power generation mechanism; and the inner cable is inserted through the outer cable, is connected to the fluid receiving mechanism and to the electric power generation mechanism, performs reciprocating motion in the outer cable in accordance with the motion of the fluid receiving mechanism, and transmits the reciprocating motion to the electric power generation mechanism.

2. The electric power generation system according to claim 1, wherein the electric power generation mechanism converts the reciprocating motion transmitted by the inner cable into rotational motion and converts the rotational motion into electric power.

3. (canceled)

4. (canceled)

5. (canceled)

6. (canceled)

7. (canceled)

8. The electric power generation system according to claim 1, wherein both end portions of the inner cable are exposed from the outer cable, a rigid first mechanical power transmission element that is connected to the fluid receiving mechanism is attached to one of the exposed end portions of the inner cable, and a rigid second mechanical power transmission element that is connected to the electric power generation mechanism is attached to the other exposed end portion of the inner cable, and wherein the fluid receiving mechanism includes a first tubular guide member that guides the first mechanical power transmission element so that the first mechanical power transmission element can perform reciprocating motion, and a second tubular guide member that guides the second mechanical power transmission element so that the second mechanical power transmission element can perform reciprocating motion.

9. The electric power generation system according to claim 1, wherein the flowing fluid is a wind, wherein the fluid receiving mechanism is disposed in a region that receives the wind and performs rotational motion in accordance with motion of the wind, and wherein the reciprocating mechanism performs the reciprocating motion on the basis of the rotational motion of the receiving mechanism.

10. (canceled)

11. (canceled)

12. (canceled)

13. The electric power generation system according to claim 1, wherein the flowing fluid is seawater, the fluid receiving mechanism includes a float that is disposed on a sea surface and that performs up-and-down motion in accordance with up-and-down motion of the sea surface, and the inner cable is connected to the float.

14. (canceled)

15. The electric power generation system according to claim 13, further comprising a tide receiving mechanism including a float that performs up-and-down motion in accordance with up-and-down motion of the sea surface and that is different from the float of the fluid receiving mechanism and up-and-down motion transmitting means that transmits the up-and-down motion of the float to the fluid receiving mechanism.

16. The electric power generation system according to claim 1, wherein the electric power generation mechanism includes a rack that includes a tooth array and that moves in a first direction and a second direction in accordance with the reciprocating motion of the reciprocating mechanism, a gear mechanism that meshes with the tooth array and rotates on the basis of movement of the rack in at least one of the first direction and the second direction, a mechanical power transmission shaft that rotates in accordance with rotation of the gear mechanism, and an electric power generator that generates electric power on the basis of rotation of the mechanical power transmission shaft.

17. The electric power generation system according to claim 16, wherein the gear mechanism includes a first gear train that meshes with the tooth array and that rotates the mechanical power transmission shaft on the basis of movement of the rack in the first direction, and a second gear train that meshes with the tooth array and that rotates the mechanical power transmission shaft on the basis of movement of the rack in the second direction.

18. The electric power generation system according to claim 17, wherein the first gear train includes an odd number of gears, wherein the second gear train includes an even number of gears, and wherein a rotation direction in which the first gear train rotates the mechanical power transmission shaft when the rack moves in the first direction coincides with a rotation direction in which the second gear train rotates the mechanical power transmission shaft when the rack moves in the second direction.

19. (canceled)

20. The electric power generation system according to claim 1, wherein the flowing fluid is water, and the fluid receiving mechanism performs rotational motion in accordance with waterflow that occurs around a ship or river flow, and wherein the reciprocating mechanism performs the reciprocating motion on the basis of the rotational motion of the receiving mechanism.

21. A reciprocating mechanism for an electric power generation system, the reciprocating mechanism being connected to a fluid receiving mechanism that is disposed in a region that receives a flowing fluid and that performs motion selected from a group consisting of rotational motion and reciprocating motion in accordance with a flow of the fluid and to an electric power generation mechanism that is disposed in a region different from the region in which the fluid receiving mechanism is disposed, the reciprocating mechanism performing reciprocating motion on the basis of the motion of the fluid receiving mechanism, and the electric power generation system generating electric power by converting the reciprocating motion into rotational motion of the electric power generation mechanism, wherein the reciprocating mechanism for the electric power generation system includes an inner cable and a tubular outer cable; the outer cable is disposed between the fluid receiving mechanism and the electric power generation mechanism; and the inner cable is inserted through the outer cable, is connected to the fluid receiving mechanism and to the electric power generation mechanism, performs reciprocating motion in the outer cable in accordance with the motion of the fluid receiving mechanism, and transmits the reciprocating motion to the electric power generation mechanism.

22. (canceled)

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. The reciprocating mechanism for an electric power generation system according to claim 21, wherein both end portions of the inner cable are exposed from the outer cable, a rigid first mechanical power transmission element that is connected to the fluid receiving mechanism is attached to one of the exposed end portions of the inner cable, and a rigid second mechanical power transmission element that is connected to the electric power generation mechanism is attached to the other exposed end portion of the inner cable, and wherein the first mechanical power transmission element performs reciprocating motion while being guided by a first tubular guide member that is disposed on the fluid receiving mechanism side, and the second mechanical power transmission element performs reciprocating motion while being guided by a second tubular guide member that is disposed on the electric power generation mechanism side.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0064] FIG. 1 is an overall schematic view of a wind electric power generation system according to a first embodiment of the present invention.

[0065] FIG. 2 illustrates a connection mechanism that connects a fluid receiving mechanism of the wind electric power generation system and a reciprocating mechanism and a connection mechanism that connects the reciprocating mechanism and an electric power generation mechanism.

[0066] FIG. 3 illustrates the operations of the connection mechanisms.

[0067] FIG. 4 illustrates the reciprocating mechanism, part (a) is a longitudinal sectional view of an outer cable and an inner cable, and part (b) is a cross-sectional view of the outer cable and the inner cable.

[0068] FIG. 5(a) and FIG. 5(b) illustrate the operation of the connection mechanism that connects the fluid receiving mechanism of the wind electric power generation system and the reciprocating mechanism.

[0069] FIG. 6(a) is an enlarged view of both end portions of the reciprocating mechanism, and FIG. 6(b) is an enlarged view of a mechanism that is included in the connection mechanism connecting the fluid receiving mechanism and the reciprocating mechanism and that enables conversion of rotational motion of the receiving mechanism into reciprocating motion even when the orientation of the receiving mechanism changes in accordance with a change in the wind direction.

[0070] FIG. 7 illustrates a connection mechanism that connects the fluid receiving mechanism and the reciprocating mechanism.

[0071] FIG. 8 is an overall schematic view of a wind electric power generation system according to a second embodiment of the present invention.

[0072] is.

[0073] FIG. 9 illustrates a connection mechanism that connects a fluid receiving mechanism of the wave electric power generation system and a reciprocating mechanism.

[0074] FIG. 10 illustrates the operation of the connection mechanism.

[0075] FIG. 11 illustrates a connection mechanism that connects a fluid receiving mechanism of the wave electric power generation system and a reciprocating mechanism according to another embodiment.

[0076] FIG. 12 illustrates a fluid receiving mechanism of a wave electric power generation system that includes a plurality of the mechanisms shown in FIGS. 8 to 10 or the mechanisms shown in FIG. 11 and that combines power.

[0077] FIG. 13 illustrates a connection mechanism that connects a reciprocating mechanism of the wave electric power generation system and an electric power generation mechanism.

[0078] FIG. 14 illustrates another connection mechanism that connects the reciprocating mechanism of the wave electric power generation system and the electric power generation mechanism, part (a) is a plan view, and part (b) is a side view.

[0079] FIG. 15 is a schematic view of a water electric power generation system for a ship seen from a side of the ship.

[0080] FIG. 16 is a schematic view of the system seen from the front side of the ship.

DESCRIPTION OF EMBODIMENTS

[0081] Hereinafter, embodiments of the present invention will be described.

Embodiment 1

[0082] (Wind Electric Power Generation System)

[0083] FIG. 1 is an overall schematic view of a wind electric power generation system. The wind electric power generation system includes a wind receiving mechanism (10), a reciprocating mechanism (20), and an electric power generation mechanism (30). The wind receiving mechanism (10) includes a rotation mechanism (40), which is rotated by wind power, and a post (50), which is used to dispose the rotation mechanism at a high position. To put it simply, the rotation mechanism (40) differs from known wind electric power generation systems in that it does not have an electric power generation mechanism, such as an electric power generator or a speed increasing device. In other respects, the rotation mechanism (40) is substantially the same as known electric power generation systems. That is, the rotation mechanism (40) includes a blade (41), a hub (42), a rotor wheel (246), a wind-direction-adjustment device (44), a brake device (not shown), an anemometer (not shown), a lightning rod (not shown), and the like. Detailed descriptions of the structures and functions of these devices, which are substantially the same as those of known electric power generation systems, are omitted.

[0084] The post (50) is set up on an area on the ground via a base (51), including a vibration damping rubber and the like. A spiral spring-shaped portion (52), which includes a vibration damping rubber and the like, is disposed in a middle part of the post. The base (51) and the spring-shaped portion (52) absorb low-frequency vibrations. The post (50) includes a wind pressure reducer (53), which is made of an elastically deformable rubber or the like, in a middle part (intermediate portion) thereof. When receiving a wind pressure of a predetermined level or higher, the wind pressure reducer (53) becomes curved due to the wind pressure in a direction such that the wind pressure is reduced. Thus, when receiving excessive wind power, an upper part of the post, above the intermediate portion, swings so that the post may not become broken or the wind receiving mechanism, which is disposed in the upper part of the post, may not become seriously damaged. With such a structure, the wind electric power generation system can reliably withstand a harsh environment. Moreover, the weight of the receiving mechanism is reduced by separating the electric power generation mechanism from the receiving mechanism. Therefore, the cost of the receiving mechanism is low, although the base (51), including a vibration damping rubber and the like, the spring-shaped portion (52), and the wind pressure reducer (53) are attached.

[0085] The reciprocating mechanism (20) converts rotational motion generated by the wind receiving mechanism (10) into reciprocating motion, and transmits the reciprocating motion to the electric power generation mechanism (30). The details of the reciprocating mechanism (20) will be described below with reference to FIG. 2 and other figures.

[0086] The electric power generation mechanism (30) is located at a site different from that of the rotation mechanism (40), which is located on the post (50). For example, the electric power generation mechanism (30) is located on a part of land that is not affected by a harsh natural environment. The electric power generation mechanism (30) generates electric power by converting reciprocating motion, which is transmitted from the rotation mechanism (40), into rotational motion. The electric power generation mechanism (30) has substantially the same structure as those of known wind electric power generation mechanisms, except that the electric power generation mechanism (30) is located at a site different from that of the wind receiving mechanism (10), such as on land, and except that the electric power generation mechanism (30) includes a mechanism that converts reciprocating motion into rotational motion. The electric power generation mechanism (30) includes a speed increasing device (31), a mechanical power transmission wheel (32), and an electric power generator (33). Electric power generated by the electric power generator is transmitted to a transformer, a transformer substation, and a transmission substation. Alternatively, the electric power may be stored in an electrical storage device. Detailed descriptions of the structures, functions, and operations of the apparatuses and facilities of the electric power generation mechanism, which are substantially the same as those of known electric power generation mechanisms, are omitted here.

[0087] FIGS. 2 and 3 illustrate a mechanical power transmission mechanism for transmitting mechanical power from the rotation mechanism (40) of the wind receiving mechanism (10) to the reciprocating mechanism (20) and a mechanical power transmission mechanism for transmitting mechanical power from the reciprocating mechanism (20) to the electric power generation mechanism (30). Regarding the mechanical power transmission mechanism for transmitting mechanical power from the rotation mechanism (40) to the reciprocating mechanism (20), a piston-crank mechanism (45), which converts rotation of the rotor wheel (246) into reciprocating motion, is attached to the rotation mechanism (40). The piston-crank mechanism (45) includes a piston (45(a)) and a crank (45(b)). The piston (45(a)) is guided by a pair of guide shafts (10b), which are attached to a housing (10a) of the wind receiving mechanism (10), so that the piston (45(a)) can perform reciprocating motion. The crank (45(b)) connects the rotor wheel (246) and the piston (45(a)). With such a structure, the piston (45(a)) performs reciprocating motion along the guide shafts (10b) in accordance with rotational motion of the rotor wheel (246).

[0088] The housing (10a) is placed on a base (10c) via a bearing (10d), and when the wind direction changes, the wind-direction-adjustment device (44) rotates relative to the base (10c) due to a rotational force generated by receiving the wind. Due to the rotation, the orientation of the housing (10a), that is, the orientation of the blade (41) is changed. The reciprocating mechanism (20) is connected to the piston (45(a)) of the piston-crank mechanism (45) and performs reciprocating motion together with the piston (45(a)).

[0089] Next, the mechanical power transmission mechanism for transmitting mechanical power from the reciprocating mechanism (20) to the electric power generation mechanism (30) basically has a structure opposite to that of the mechanical power transmission mechanism for transmitting mechanical power from the rotation mechanism (40) of the wind receiving mechanism (10) to the reciprocating mechanism (20). That is, reciprocating motion of the reciprocating mechanism (20) is converted into rotational motion via a piston crank (30a) of the electric power generation mechanism (30). The piston crank (30a) includes a piston (30aa) and a crank (30ab). The piston (30aa) is guided by a pair of guide shafts (30c), which are attached to a housing (30b), so that the piston (30aa) can perform reciprocating motion. The crank (30ab) connects the mechanical power transmission wheel (32), which is connected to the speed increasing device (31), and the piston (30aa). With such a structure, the piston (30aa) performs reciprocating motion along the guide shafts (30c) in accordance with reciprocating motion of the reciprocating mechanism (20). Moreover, the mechanical power transmission wheel (32) performs rotational motion in accordance with the reciprocating motion of the piston (30aa).

[0090] As illustrated in FIG. 4, the reciprocating mechanism (20) includes an inner cable (21) and a tubular outer cable (22). The outer cable (22) is disposed between the wind receiving mechanism (10) and the electric power generation mechanism (30). The inner cable (21) is inserted through the outer cable (22) and connected to the wind receiving mechanism (10) and to the electric power generation mechanism (30). In accordance with motion of the wind receiving mechanism (10), the inner cable (21) performs reciprocating motion in the outer cable (22) and transmits the reciprocating motion to the electric power generation mechanism. Both end portions of the inner cable (21) are exposed from the outer cable (22).

[0091] FIG. 5 shows enlarged views of a mechanical power transmission portion for transmitting mechanical power from the rotation mechanism (40) of the wind receiving mechanism (10) to the reciprocating mechanism (20). FIG. 5(a) corresponds to FIG. 2, and FIG. 5(b) corresponds to FIG. 3. FIG. 5(a) is an enlarged view of both end portions of the reciprocating mechanism (20). Both end portions (21a) and (21b) of the inner cable (21) are exposed from the outer cable (22) (regarding the numeral 21b, see FIG. 6(a)). Rigid mechanical power transmission elements (23) and (24) are respectively attached to both exposed end portions (21a) and (21b) of the inner cable (21) so as to be coaxial with the inner cable. Moreover, rigid tubular guides (25) and (26) are disposed in the housing (10a) of the wind receiving mechanism (10) and the housing (30b) of the electric power generation mechanism (30). The tubular guides (25) and (26) contain the mechanical power transmission elements (23) and (24) and guide the mechanical power transmission elements (23) and (24) so that the mechanical power transmission elements (23) and (24) can move (or can slide) in the axial direction. By using the combination of the mechanical power transmission elements (23) and (24) and the tubular guides (25) and (26), the rotational motion of the wind receiving mechanism (10) is reliably transmitted to the inner cable (21), and the reciprocating motion of the inner cable (21) is reliably transmitted to the rotation mechanism of the electric power generation mechanism (30). The mechanical power transmission elements (23) and (24) and the tubular guides (25) and (26) can be made from, for example, a metal material.

[0092] The tubular guide (25) is fixed to the housing (10a) directly or via another member. The tubular guide (26) is fixed to the housing (30b) directly or via another member. With such a structure, the inner cable (21) can be prevented from becoming buckled at both end portions (21a) and (21b) of the inner cable (21), which are exposed from the outer cable (22).

[0093] Moreover, as described above, the wind receiving mechanism (10) has a function of changing its orientation in accordance to the wind direction. Therefore, twisting of the inner cable (21) may occur. In the present embodiment, twisting of the inner cable (21) is prevented by using a structure shown in an enlarged view of FIG. 6(b).

[0094] In FIG. 6(b), the piston (45(a)) includes a containing portion (46) (containing space). The containing portion (46) has an opening in its end surface facing the reciprocating mechanism (20). The containing portion (46) includes an enlarged diameter portion (46(a)), which is inside the containing portion (46) and which has a diameter larger than that of the opening in the end surface. A connection member (47) is attached to an end portion of the tubular guide (25). The connection member (47) includes a protruding portion (48) on a side opposite to a surface to which the tubular guide (25) is attached. The protruding portion (48) has a shape that is complementary to the containing portion (46), that is, a shape in which a distal end portion (48a) has an enlarged diameter. The distal end portion (48a) is contained in the enlarged diameter portion (46(a)) of the containing portion (46).

[0095] A gap is formed between the protruding portion (48) and the containing portion (46), and thereby the protruding portion (48) can rotate in the containing portion (46). Moreover, a bearing (10e) is disposed on an end surface of the connection member (47) facing the piston (45(a)).

[0096] In such a structure, the piston (45(a)) can rotate relative to the connection member (47), while movement (extraction) of the connection member (47) relative to the piston (45(a)) in the up-and-down direction in FIG. 6(b) is suppressed. That is, it is possible to connect the piston (45(a)) and the inner cable (21) while preventing twisting of the inner cable (21) due to rotation of the wind receiving mechanism (10).

[0097] In FIG. 6(b), a guide member (49) is attached to the piston (45(a)). The guide member (49) has a pair of through-holes (49a) through which the guide shafts (10b) are inserted.

[0098] FIG. 7 is a sectional view of another example of a piston-crank mechanism. A piston-crank mechanism (245) includes a piston (245(a)), a rotor wheel (246) that rotates together with a rotor shaft (43), a crank (247) that connects the piston (245(a)) and the rotor wheel (246), a cylinder (248) that contains the piston (245(a)) so that the piston (245(a)) can perform up-and-down motion, and a connection member (249) that is contained in the cylinder (248) together with the piston (245(a)).

[0099] The tubular guide (25) and the mechanical power transmission element (23) are connected to one end of the connection member (249). A protruding portion (250), which includes a distal end portion (250a) having an enlarged diameter, is disposed at the other end of the connection member (249). The piston (245(a)) has a containing portion (251), which has a shape complementary to the protruding portion (250). The containing portion (251) includes an enlarged diameter portion (251a), which has a larger diameter so that the distal end portion (250a) can be fitted into the enlarged diameter portion (251a), and the distal end portion (250a) is contained in the enlarged diameter portion (251a).

[0100] A gap is formed between the protruding portion (250a) and the containing portion (251a), and thereby the protruding portion (250) can rotate in the containing portion (251). Moreover, a bearing (252) is disposed on an end surface of the connection member (249) facing the piston (245(a)). In such a structure, as the rotor wheel (246) rotates, the piston (245(a)) moves up and down in the cylinder (248).

[0101] Also with the structure shown in FIG. 7, it is possible to connect the piston (245(a)) and the inner cable (21) while preventing twisting of the inner cable (21) due to rotation of the wind receiving mechanism (10).

Embodiment 2

[0102] (Wave Electric Power Generation System)

[0103] FIG. 8 is an overall schematic view of a wave electric power generation system. The wave electric power generation system includes a wave power receiving mechanism (110), a reciprocating mechanism (120), and an electric power generation mechanism (130). The wave power receiving mechanism (110) is configured so that a float (111) is disposed in a sea-surface region and moves up and down in accordance with up-and-down motion the sea surface. The reciprocating mechanism (120) transmits the up-and-down motion of the float (111) as reciprocating motion, the electric power generation mechanism (130) converts the reciprocating motion into rotational motion, and thereby electric power is generated.

[0104] As in the embodiment 1, the electric power generation mechanism (130) includes a mechanism that converts reciprocating motion into rotational motion (this mechanism will be described in detail below with reference to FIGS. 13 and 14), a mechanical power transmission shaft (134), a speed increasing device (135), and an electric power generator (136). Electric power generated by the electric power generator (136) is transmitted to a transmission substation via a transformer and a transformer substation. Alternatively, the electric power may be stored in an electrical storage device. The structures, functions, and operations of apparatuses and facilities of the electric power generation mechanism are substantially the same as those of known electric power generation mechanisms, except that a mechanism for changing reciprocating motion into rotational motion is provided. Therefore, detailed descriptions are omitted here.

[0105] FIGS. 9 and 10 illustrate a connection mechanism that connects the wave power receiving mechanism (110) of the wave electric power generation system and the reciprocating mechanism (120). FIG. 9 illustrates a state when the sea surface falls, and FIG. 10 illustrates a state when the sea surface rises. In the wave power receiving mechanism (110), one or more guide rings (114) are attached to the float (111). One or more guide rods (113) are attached to a housing (112), which is attached to a wall that is in contact with the sea surface, in the up-and-down direction (the direction in which the sea surface rises and falls. The guide rods (113) are inserted through the guide rings (114). With such a structure, the guide rods (113) guide the float (111) via the guide rings (114) in the up-and-down direction. As a result, the float (111) moves up and down in accordance with up-and-down motion of the sea surface. A plate member (117), which has a facing surface (116) facing the float (111) with a predetermined distance therebetween, is attached to a portion below the float (111). Thus, a gap, which allows seawater to flow thereinto, is formed between the float (111) and the facing surface (116). An opening (112a) is formed in a bottom plate of the housing (112). With the opening (112a), flow of seawater toward the float (111) and flow of seawater in the opposite direction are not blocked, and the float (111) can smoothly move up and down. The numeral 115 denotes an upper plate member that is attached to the upper surface of the float (111).

[0106] The reciprocating mechanism (120) includes inner cables (121) and tubular outer cables (122), through which the inner cables (121) are inserted. The inner cables (121) can perform reciprocating motion (for example, while sliding) in the outer cables (122). Lower end portions of the inner cables, which are connected to the wave power receiving mechanism (110), are exposed from the outer cables (122). Rigid mechanical power transmission elements (123) are attached to the exposed end portions of the inner cables (121) so as to be coaxial with the inner cables (121). The mechanical power transmission elements (123) are attached to the upper plate member (115). Tubular guides (124) are disposed in the housing (112), and the mechanical power transmission elements (123) perform reciprocating motion in the tubular guides (124).

[0107] Because a space between the lower surface of the float (111) and the upper surface (116) (surface facing the float with a gap therebetween) of the plate member (117) is located below the float (111), the space is below the sea surface and filled with seawater. When the sea surface rises, the sea surface does not affect upward motion of the float, because the sea surface has the same specific gravity as seawater. When the sea surface falls, the response of the float to this motion is low and a force that moves the float downward is small, because the float has a lower specific gravity than seawater. However, the seawater in the space between the lower surface of the float (111) and the upper surface (116) of the plate member (117) functions as a weight when the sea surface falls and thereby increases the response of the float and increases the force that moves the float (111) downward. As a result, the reciprocating mechanism (120) can effectively perform reciprocating motion.

[0108] Although not illustrated, a spring or the like may be disposed in the vicinity of a connection portion between the float (111) and the reciprocating mechanism (120). By doing so, it is possible to provide a mechanism that adjusts, by using the force of the spring, the difference in response (the difference in torque) between a time when the sea surface rises and a time when the sea surface falls.

[0109] FIG. 11 illustrates a connection mechanism according to another embodiment, which is different from the connection mechanism shown in FIGS. 8, 9, and 10. The connection mechanism shown in FIGS. 8, 9, and 10 has a structure in which the wave power receiving mechanism, which is a fluid receiving mechanism, is directly attached to a wall that is in contact with the sea surface. In the connection mechanism shown in FIG. 11, the wave power receiving mechanism is not directly attached to the wall in contact with the sea surface but is attached to the wall via a tide receiving mechanism (190). That is, the tide receiving mechanism (190) includes a pair of guide rods (113a) that are fixed, in the up-and-down direction, to the wall in contact with the sea surface via a fixing member (not shown), guide rings (114a) through which the guide rods (113a) are inserted so that the guide rings (114a) can perform up-and-down motion, and floats (111a) that are attached to the guide rings (114a). The housing (112) has an upper plate extending toward the floats (111a), and the floats (111a) are attached to the extended parts of the upper plate (112b) (corresponding to up-and-down motion transmitting means in the present invention).

[0110] When the tide receiving mechanism (190) is attached to the wave power receiving mechanism, the floats (111a), which are attached to the guide rods (113a) via the guide rings (114a), move up and down in accordance with change in the tide level. The up-and-down motion is transmitted to the wave power receiving mechanism. As a result, an advantage is obtained in that the stroke of the up-and-down motion of the float (111) of the wave power receiving mechanism can be reduced and the size of the wave power receiving mechanism can be made compact.

[0111] In this example, the tide receiving mechanism includes a pair of guide rods. However, the tide receiving mechanism may include one guide rod or three or more guide rods. In this example, the guide rods are disposed at positions that oppose each other. However, the guide rods may be disposed side by side.

[0112] Regarding the embodiment shown in FIG. 11, description of portions that overlaps those of FIGS. 9 and 10 are omitted and numerals in the figure are also omitted.

Embodiment 2-1

[0113] The embodiment presented in the present specification is a wave electric power generation system including one set of an inner cable and an outer cable. However, the wave electric power generation system may include two or more sets of inner cables and outer cables. For example, by using a combination of plurality of fluid receiving mechanisms and reciprocating mechanisms so as to combine power to at least one reciprocating mechanism, the combined reciprocating motion may be transmitted to the electric power generation mechanism. With the electric power generation system, by using a combination of a plurality of fluid receiving mechanisms so as to combine power, it is possible to increase the energy, to realize an appearance taking the environment into account, and to increase the mass-productivity of facilities.

[0114] FIG. 12 illustrates an example of such a wave electric power generation system in use. In this figure, the wave electric power generation system includes a housing (170) in which the electric power generation mechanism (130) and the like are contained, a plurality of the wave power receiving mechanisms (110), and a plurality of the reciprocating mechanisms (120) that connect the housing (170) and the wave power receiving mechanisms (110). In the example shown in this figure, the housing (170) is disposed on an upper surface (180a) of a breakwater (180). The wave power receiving mechanisms (110) are attached to a side surface (180b) of the breakwater (180) and lower parts of the wave power receiving mechanisms (110) are immersed in seawater.

[0115] Mechanical power that is generated by up-and-down motion of the float (111) of each of the wave power receiving mechanisms (110) is transmitted to the housing (170) via a corresponding one of the reciprocating mechanisms (120). The housing (170) includes a power-combining mechanism (not shown) that combines mechanical power that is transmitted via the reciprocating mechanisms (120). The power-combining mechanism is, for example, a mechanism that connects the inner cable (121) of each of the reciprocating mechanism (120) to a rack (132) illustrated in FIG. 13. The electric power generation mechanism (130) can generate large electric power, because the mechanical power combined by the power-combining mechanism is greater than the mechanical power from each of the wave power receiving mechanisms (110).

[0116] The mechanical power transmission element (123) and the tubular guide (124) may be made from, for example, a metal material. By providing the mechanical power transmission element (125) and the tubular guide (126), as in the embodiment 1, the inner cable (121) can be prevented from becoming buckled at end portions of the inner cable (121), which are exposed from the outer cable (122).

[0117] The structure of each of the wave power receiving mechanisms (110) shown in FIG. 12 is slightly changed in design from the wave power receiving mechanism illustrated in FIGS. 9 and 10. However, the structures of these mechanisms are substantially the same and the functions of these mechanisms are also substantially the same. Therefore, portions having substantially the same structures are denoted by the same numerals and the detailed descriptions are omitted here. The difference in design between the wave power receiving mechanisms illustrated in FIG. 12 and the wave power receiving mechanism illustrated in FIGS. 9 and 10 is that, in the wave power receiving mechanism illustrated in FIG. 12, guide holes (114) are formed in the four corners of the float (111), and the guide rods (113), which are attached to the housing (112) in the up-and-down direction (in which the sea surface rises and falls), are inserted through the guide holes (114).

[0118] Another difference is that two reciprocating mechanisms are connected to the float (111) in FIGS. 9 and 10, while one reciprocating mechanism is connected to each of the floats (111) in FIG. 12.

[0119] The above description is a comparison with the FIGS. 9 and 10. Description of a comparison with FIG. 11, which is the same as above, is omitted here.

Embodiment 2-2

[0120] FIG. 13 illustrates an example of a mechanism that converts reciprocating motion of the reciprocating mechanism (120) into rotational motion of the electric power generation mechanism (130). An end portion of the inner cable (121) on the electric power generation mechanism side is exposed from the outer cable (122), and the rigid mechanical power transmission element (125) is attached to this end portion so as to be coaxial with the inner cable. A rigid tubular guide (126), which contains the mechanical power transmission element (125) and which guides the mechanical power transmission element in the axial direction, is disposed on the electric power generation mechanism side. Thus, the reciprocating motion of the inner cable is reliably transmitted to a rotation device of the electric power generation mechanism.

[0121] The mechanical power transmission element (125) and the tubular guide (126) may be made from, for example, a metal material. By providing the mechanical power transmission element (125) and the tubular guide (126), as in the embodiment 1, the inner cable (121) can be prevented from becoming buckled at end portions of the inner cable (121), which are exposed from the outer cable (122).

[0122] Regarding the sea surface, because the tide occurs and the wave height constantly changes, the amplitude of the inner cable (121) and the reference position of the reciprocating motion of the inner cable (121) change with time. In order to adapt to this change, for example, a rack-and-pinion mechanism illustrated in FIG. 13 may be applied to the electric power generation mechanism (130).

[0123] In the example shown in this figure, the electric power generation mechanism (130) includes a slider (131), the rack (132), and a gear mechanism (133). The slider (131) includes, for example, a large number of rollers (131a) that are arranged along a line. The rack (132) is placed on the rollers (131a) and is connected to the mechanical power transmission element (125) of the reciprocating mechanism (120). Due to the reciprocating motion of the inner cable (121), the rack (132) moves in a first direction (D1) and in a second direction (D2), which is opposite to the first direction (D1), on the slider (131). In the example shown in FIG. 13, the first direction (D1) is a direction in which the rack (132) moves when the inner cable (121) is pushed due to the rise of the sea surface, and the second direction (D2) is a direction in which the rack (132) moves when the inner cable (121) is pulled due to the fall of the sea surface. The slider (131) and the rack (132) each have a sufficiently large length in the first direction (D1) and the second direction (D2) so that they can accommodate changes in the position of the sea surface caused by the tide or the like.

[0124] The rack (132) extends in a direction that crosses the first direction (D1) and the second direction (D2) and includes a first tooth array (132a) having a plurality of rack teeth and a plurality of second tooth arrays (132b). The second tooth array (132b) is disposed at a higher position than the first tooth array (132a), that is, at a position close to the mechanical power transmission shaft (134).

[0125] The gear mechanism (133) meshes with the tooth array of the rack (132) and rotates the mechanical power transmission shaft (134) on the basis of movement of the rack (132) in at least one of the first direction (D1) and the second direction (D2). In the present embodiment, the gear mechanism (133) includes a first gear train (161), which meshes with the first tooth array (132a) and rotates the mechanical power transmission shaft (134) on the basis of movement of the rack (132) in the first direction (D1); and a second gear train (162), which meshes with the second tooth array (132b) and rotates the mechanical power transmission shaft (134) on the basis of movement of the rack (132) in the second direction (D2). That is, in the present embodiment, the mechanical power transmission shaft (134) is rotated on the basis of movements of the rack (132) in both of the first direction (D1) and the second direction (D2).

[0126] For example, the first gear train (161) includes an odd number of (in FIG. 13, three) gears, and the second gear train (162) includes an even number of (in FIG. 13, two) gears. In this case, the rotation direction (R) in which the first gear train (161) rotates the mechanical power transmission shaft (134) when the rack (132) moves in the first direction (D1) coincides with the rotation direction (R) in which the second gear train (162) rotates the mechanical power transmission shaft (134) when the rack (132) moves in the second direction (D2).

[0127] An uppermost gear (161a), which is one of gears (pinions) included in the first gear train (161), is connected to the mechanical power transmission shaft (134). The gear (161a) includes a first one-way clutch (unidirectional clutch) that transmits mechanical power generated by movement of the rack (132) in the first direction (D1) to the mechanical power transmission shaft (134) and that does not transmit mechanical power generated by movement of the rack (132) in the second direction (D2) to the mechanical power transmission shaft (134). An uppermost gear (162a), which is one of gears (pinions) included in the second gear train (162), is connected to the mechanical power transmission shaft (134). The gear (162a) includes a second one-way clutch that transmits mechanical power generated by movement of the rack (132) in the second direction (D2) to the mechanical power transmission shaft (134) and that does not transmit mechanical power generated by movement of the rack (132) in the first direction (D1) to the mechanical power transmission shaft (134).

[0128] By using the rack-and-pinion mechanism having the structure described above, it is possible to continue generating electric power irrespective of changes in the position of the sea surface. Moreover, because the mechanical power transmission shaft (134) rotates in the same rotation direction (R) in either of the time when the sea surface rises and the time when the sea surface falls, it is possible to achieve a higher electric power generation efficiency compared to a case where electric power generation is performed in only one of the time when the sea surface rises and the time when the sea surface falls.

[0129] In FIG. 13, the rack (132) has the first tooth array (132a) and the second tooth array (132b). However, the rack (132) may have only one type of tooth array, and, by adjusting the diameter of gears included in the first gear train (161) and the second gear train (162), the difference in the height between the rack (132) and the mechanical power transmission shaft (134), which occurs due to the difference in the number of gears, may be accommodated. Although the electric power generation efficiency decreases, only one type of gear train may be used, and the mechanical power transmission shaft (134) may be rotated only in one of the time when the sea surface rises and the time when the sea surface falls.

[0130] An elastic member, which connects an end portion of the rack (132) opposite to an end portion to which the mechanical power transmission element (125) is attached and a structure that does not move together with the rack (132), may be disposed. In this case, for example, the elastic member is pulled and stores elastic energy when the rack (132) moves in the second direction (D2), and the elastic energy of the elastic member may assist movement of the rack (132) when the rack (132) moves in the first direction (D1). By doing so, it is possible to offset the weight of the inner cable (121) and the frictional resistance between the inner cable (121) and the outer cable (122) by using the elastic energy and to increase the electric power generation efficiency. Instead of the elastic member, a weight that stores potential energy when the rack (132) moves in the second direction (D2) may be connected to an end portion of the rack (132), and the potential energy may be used to assist movement of the rack (132) in the first direction (D1).

Embodiment 2-3

[0131] FIG. 14 illustrates another connection mechanism that converts reciprocating motion of the reciprocating mechanism (120) into rotational motion of the electric power generation mechanism (130), part (a) is a plan view, and part (b) is a side view. In the example shown in this figure, the electric power generation mechanism (130) includes a rack (140) and a gear mechanism (141). As in the aforementioned example, the rack (140) is placed, for example, on a slider. Due to the reciprocating motion of the inner cable (121), the rack (140) moves in the first direction (D1) and in the second direction (D2), which is opposite to the first direction (D1).

[0132] The rack (140) includes a first tooth array (140a) and a second tooth array (140b), each having a plurality of rack teeth, on both side surfaces.

[0133] The gear mechanism (141) meshes with the tooth arrays of the rack (140) and rotates the mechanical power transmission shaft (134) on the basis of movement of the rack (140) in at least one of the first direction (D1) and the second direction (D2). In the present embodiment, the gear mechanism (141) includes a first gear (142) that meshes with the first tooth array (140a), a second gear (144) that is connected to the first gear (142) via a shaft (143), a third gear (145) that meshes with the second tooth array (140b), a fourth gear (147) that is connected to the third gear (145) via a shaft (146), and a fifth gear (148) that meshes with the second gear (144) and the fourth gear (147). The mechanical power transmission shaft (134) is connected to the fifth gear (148).

[0134] The second gear (144) includes a first one-way clutch that allows the second gear (144) to be rotated by mechanical power that is transmitted from the shaft (143) when the rack (140) moves in the first direction (D1) and that does not allow the second gear (144) to be rotated by mechanical power that is transmitted from the shaft (143) when the rack (130) moves in the second direction (D2). The fourth gear (147) includes a second one-way clutch that allows the fourth gear (147) to be rotated by mechanical power that is transmitted from the shaft (146) when the rack (140) moves in the second direction (D2) and that does not allow the fourth gear (147) to be rotated by mechanical power that is transmitted from the shaft (146) when the rack (140) moves in the first direction (D1).

[0135] Therefore, when the rack (140) moves in the first direction (D1), the gears (142,144,148) rotate as indicated by solid line arrows in FIG. 14(a). Accordingly, the mechanical power transmission shaft (134) rotates in the direction indicated by a solid line arrow in FIG. 14(b). When the rack (140) moves in the second direction (D2), the gears (145,147,148) rotate as indicated by broken line arrows in FIG. 14(a). Accordingly, the mechanical power transmission shaft (134) rotates in the direction indicated by the solid line arrow in FIG. 14(b).

[0136] With this structure, even in wave electric power generation, in which the amplitude of reciprocating motion considerably changes in accordance with the tide level and the amplitude of waves, it is possible to stably transmit continuous unidirectional rotational motion to the electric power generation mechanism.

Embodiment 3

(Electric Power Generation System Attached to Ship)

[0137] FIGS. 15 and 16 illustrate an example of a water electric power generation system for a ship. FIG. 15 illustrates the structure of the system seen from a side of the ship, and FIG. 16 illustrates the structure of the system when seen from the front of the ship. A screw (201) (corresponding to a receiving mechanism in the present invention) is fixed to the ship via a joint or the like, and the screw (201) is rotated by waterflow that is generated as the ship moves, flow of sea water or river water, or the like. In this case, the screw (201) may be a simple propeller. However, preferably, an Archimedes' screw is used to increase the efficiency. In the present embodiment, FIG. 15 illustrates an Archimedes' screw. A machine chamber (202), which is watertight, is connected to this rotation. In the machine chamber (202), a rotor unit and a simple lightweight motion converter, which coverts rotational motion into reciprocating motion by using a crank mechanism, a gear-change mechanism, or the like, are disposed. Because an example of this structure has been described in detail in the description of the wind electric power generation system, description of the structure will be omitted here. Energy that has been converted into reciprocating motion in the machine chamber (202) is transmitted to a motion converter (206) (constituting a part of an electric power generation mechanism in the present invention), which is located at any appropriate position on the ship deck, via a reciprocation transmitting cable (corresponding to a reciprocating mechanism in the present invention). Here, the reciprocation transmitting cable, which corresponds to a reciprocating mechanism in the present invention and which transmits a displacement of one end portion of the cable to the other end portion of the cable, is not limited to a combination of an inner cable (203) and an outer cable (204). For example, a hydraulic cable, which uses oil pressure, or the like can be used. The transmitted reciprocating energy is converted by the motion converter (206) into rotational energy and drives an electric power generator (207) (constituting a part of an electric power generation mechanism in the present invention). The numeral (208) denotes a spring, and the reciprocating torque of the inner cable (203) is adjusted by the spring. In the figures, the numeral (205) denotes joints that fix the reciprocating-energy transmitting cable to the hull, and the numeral (210) denotes a joint that fixes the screw to the hull. The numeral (209) denotes the water surface.

[0138] Heretofore, examples in which the present invention is applied to a wind electric power generation system, a wave electric power generation system, and an electric power generation system attached to a ship have been described. However, the present invention is not limited to these embodiments and can be also applied to an electric power generation system that utilizes, for example, river flow. Moreover, the present invention can be effectively applied not only to a large electric power generation facility but also to a small electric power generation facility, such as a small emergency electric power generation system for driving LED lighting or an oscillator, a small home electric power generation system utilizing wind power or wave power, and an electric power generation system for leisure activities.

[0139] For reference, the claims of two patent applications over which the present application claims priority are cited below (including amendments). [0140] (Japanese Patent Application No. 2014-164159) [0141] [Claim 1]

[0142] An electric power generation system and an electric power generation plant in which an energy transmitting cable, which includes an outer cable and an inner cable that is slidably inserted into the outer cable, is used to transmit reciprocating motion obtained from natural energy. [0143] [Claim 2]

[0144] The electric power generation system and the electric power generation plant according to Claim 1, wherein one of two ends of the inner cable of the energy transmitting cable according to Claim 1 is connected to an energy converter that converts the natural energy into reciprocating motion, and the other end is connected to an electric power generation facility that converts reciprocating motion into electric power. [0145] [Claim 3]

[0146] The electric power generation system and the electric power generation plant according to Claim 1 or 2, wherein the outer cable of the energy transmitting cable according to Claim 1 has a structure including at least one layer that is one or a combination of a single layer, a mesh structure layer, and the like and the outer cable has flexibility and rigidity, and wherein a material of the outer cable includes one or a combination of a resin, a metal, a carbon material, and a synthetic fiber. [0147] [Claim 4]

[0148] The electric power generation system and the electric power generation plant according to Claim 1 or 2, wherein a material that includes at least one of a metal, a carbon material, and a synthetic fiber is used as a material of the inner cable of the energy transmitting cable according to Claim 1, and wherein the inner cable has a structure of a single wire, a stranded wire, or a composite of a single wire and a stranded wire so as to have flexibility and rigidity. [0149] [Claim 5]

[0150] The electric power generation system and the electric power generation plant according to Claim 1 or 2, wherein the energy transmitting cable has a length of 10 centimeters or greater, and, when in use, the energy transmitting cable is linear or has at least one or more curved portions. [0151] [Claim 6]

[0152] The energy transmission cable according to Claim 1, 2, or 3, wherein an inner surface of the outer cable and an outer surface of the inner cable are coated so as to reduce a friction coefficient when the inner cable slides and are waterproof processed. [0153] [Claim 7]

[0154] The electric power generation system and the electric power generation plant according to Claim 1, wherein an energy combining unit combines reciprocating energy that is transmitted by a plurality of facilities in each of which the energy transmitting cable is connected to the energy converter according to Claim 1 or 2, which converts natural energy into reciprocating motion, and wherein the combined reciprocating energy is transmitted to an electric power generation facility that converts the reciprocating energy into electric power by using at least one or more energy transmitting cables. [0155] [Claim 8]

[0156] The electric power generation system and the electric power generation plant according to Claim 1, wherein the natural energy, which is a mechanical power source, is one of wave power, tidal power, and wind power. [0157] [Claim 9]

[0158] An energy transmission cable for transmitting reciprocating energy in an electric power generation system that converts natural energy into electric power, the energy transmission cable comprising: an outer cable that is made of a material that is one or a combination of a resin, a metal, a carbon material, and a synthetic fiber and that has a structure including at least one or more layers, each of the layers being one or a combination of a single layer, a mesh-structure layer, and the like and having flexibility and rigidity; and an inner cable that is inserted into the outer cable so as to be slidable, that is made of a material including at least one of a metal, a carbon material, and a synthetic fiber, and that has a structure of a single wire, a stranded wire, or a composite structure of a single wire and a stranded wire so as to have flexibility and rigidity. [0159] (Japanese Patent Application No. 2014-221736) [0160] [Claim 1]

[0161] An electric power generation system for converting natural energy into electric power, comprising: a mechanical power converter that converts rotational energy into reciprocating energy; and a mechanical power converter that converts reciprocating energy into rotational energy. [0162] [Claim 2]

[0163] The electric power generation system according to Claim 1, wherein the mechanical power converter of the electric power generation system according to Claim 1, which converts rotational energy into reciprocating energy, converts rotational energy that a rotor unit including a screw, a propeller, and the like generates by converting natural energy into reciprocating energy, and wherein the mechanical power converter of the electric power generation system according to Claim 1 that converts reciprocating energy into rotational energy converts reciprocating energy transmitted by a reciprocating energy transmitting cable into rotational energy. [0164] [Claim 3]

[0165] The electric power generation system according to Claim 1 or 2, wherein a natural energy source is waterflow that occurs around a ship. [0166] [Claim 4]

[0167] The electric power generation system according to Claim 1 or 2, wherein a natural energy source is wind power or an airflow that occurs around an automobile or a ship. [0168] [Claim 5]

[0169] The electric power generation system for converting natural energy into electric power according to any one of Claims 1, 2, 3, and 4, wherein the mechanical power converter that converts rotational energy into reciprocating energy uses one of a crank mechanism, a Scotch yoke mechanism, and a rack-and-pinion mechanism, and wherein the mechanical power converter that converts reciprocating energy into rotational energy uses one of a crank mechanism, a Scotch yoke mechanism, and a rack-and-pinion mechanism.

REFERENCE SIGNS LIST

[0170] 10 wind receiving mechanism, 10a housing of wind receiving mechanism, 10b guide shaft, 10c base, 10d bearing, 10e bearing, 20 reciprocating mechanism, 21 inner cable, 21a one of exposed end portions of inner cable, 21b the other exposed end portion of inner cable, 22 outer cable, 23 mechanical power transmission element, 24 mechanical power transmission element, 25 tubular guide, 26 tubular guide, 30 electric power generation mechanism, 30a piston crank, 30aa piston, 30ab crank, 30b housing, 30c guide shaft, 31 speed increasing device, 32 mechanical power transmission wheel, 33 electric power generator, 40 rotation mechanism, 41 blade, 42 hub, 43 rotor shaft, 44 wind-direction-adjustment device, 45 piston-crank mechanism, 45(a) piston, 45(b) crank, 46 containing portion, 46(a) enlarged diameter portion, 47 connection member, 48 protruding portion, 48a distal end portion, 49 guide member, 49a through-hole, 50 post, 51 base, 52 spiral spring-shaped portion, 53 wind pressure reducer, 110 wave power receiving mechanism, 111 float, 111a float, 112 housing, 112a opening of housing, 112b extending upper plate, 113 guide rod, 113a guide rod, 114 guide ring, 114a guide ring, 114 guide hole, 115 upper plate member, 116 surface facing the float with a gap therebetween, 117 plate member (member having a surface facing a float), 120 reciprocating mechanism, 121 inner cable, 122 outer cable, 123 mechanical power transmission element, 124 tubular guide, 125 mechanical power transmission element, 126 tubular guide, 130 electric power generation mechanism, 131 slider, 131a roller, 132 rack, D1 first direction, D2 second direction, 132a first tooth array, 132b second tooth array, 133 gear mechanism, 134 mechanical power transmission shaft, R rotation direction in which mechanical power transmission shaft is rotated, 135 speed increasing device, 136 electric power generator, 140 rack, D1 first direction of rack, D2 second direction of rack, 140a first tooth array, 140b second tooth array, 141 gear mechanism, 142 first gear, 143 shaft, 144 second gear, 145 third gear, 146 shaft, 147 fourth gear, 148 fifth gear, 161 first gear train, 161a uppermost gear, 162 second gear train, 162a uppermost gear, 170 housing, 180 breakwater, 180a upper surface of breakwater, 180b side surface of breakwater, 190 tide receiving mechanism, 201 screw, 202 machine chamber, 203 inner cable, 204 outer cable, 206 motion converter, 207 electric power generator, 208 reciprocating torque adjustment spring, 209 water surface, 245 piston-crank mechanism, 245(a) piston, 246 rotor wheel, 247 crank, 248 cylinder, 249 connection member, 250 protruding portion, 250a distal end portion, 251 containing portion, 251a enlarged diameter portion, 252 bearing