Abstract
The invention relates to a piston machine which comprises: a housing with a chamber with has a substantially circle sector-shaped cross-section; a pivotal piston which is designed as a pivoting element, is arranged in the housing and comprises a first working surface, wherein the housing and the piston define at least one first variable working chamber; a drive or output which is connected to the piston; and an outlet which is arranged in the working chamber for discharging a working fluid. The housing has a cooling opening in at least one housing wall, said opening leading to the chamber at least for convectively cooling a piston side opposite the first working surface by means of a coolant.
Claims
1. Piston machine, comprising: a housing with a chamber which has a substantially circle sector-shaped cross-section, a pivotal piston which is designed as a pivoting element, is arranged in the housing and includes a first working surface, the housing and the piston define at least one first variable working chamber, a drive or output connected to the piston, an outlet arranged in the working chamber for discharging a working fluid, the housing having two or more joined housing parts, which are each circle sector-shaped, but turned by 180, and form a common cavity, wherein one said pivotal piston being assigned to each housing part, and two adjacent housing parts together with their pistons define a common variable working chamber, the housing having a cooling opening in at least one housing wall, said opening leading to the chamber at least for convectively cooling a side of the piston opposite the first working surface by a coolant.
2. Piston machine according to claim 1, wherein the chamber is delimited by a wall, which is circular arc-shaped in cross-section, and the cooling opening is provided in the circular arc-shaped wall.
3. Piston machine according to claim 2, wherein the opening in the circular arc-shaped wall is defined by a center angle which is at most as large as a pivot angle of the piston.
4. Piston machine according to claim 2, wherein the circular arc-shaped wall defines a second center angle, wherein a piston side facing the circular arc-shaped wall is circular arc-shaped in cross-section and defines a third center angle, wherein the second center angle is as large as the third center angle or smaller or larger than the third center angle.
5. Piston machine according to claim 2, wherein the opening in the circular arc-shaped wall extends over an entire axial length of the circular arc-shaped wall.
6. Piston machine according to claim 2, wherein the piston has a second working surface on a side opposite the first working surface, and the piston and the housing define a second variable working chamber with a second outlet valve arranged therein, wherein the cooling opening separates the first working chamber from the second working chamber.
7. Piston machine according to claim 2, wherein the circular arc-shaped wall and/or the front wall and/or the rear wall and/or the side wall are divided into two parts by the cooling opening.
8. Piston machine according to claim 1, wherein a pivot movement of the piston defines a pivot plane and the chamber is delimited by a front wall and a rear wall, wherein the front wall and the rear wall are parallel to the pivot plane, and the cooling opening is provided in the front wall and/or in the rear wall.
9. Piston machine according to claim 8, wherein the opening in the rear wall and/or front wall extends over an entire radial length of the rear wall and/or front wall.
10. Piston machine according to claim 1, wherein the working chamber is open or closed as a function of the pivot position of the piston.
11. Piston machine according to claim 1, wherein the chamber is delimited by a side wall facing away from the first working surface, wherein the cooling opening is provided in the side wall.
12. Piston machine according to claim 11, wherein the cooling opening in the side wall extends over an entire radial and/or axial length of the side wall.
13. Piston machine according to claim 1, further comprising a second wall, which is circular arc-shaped in cross section, is attached to the piston, is arranged on a radius smaller than a maximum radial length of the piston and in at least one pivot position of the piston engages into a passage of a side wall, wherein a second variable working chamber is defined at least by the second circular arc-shaped wall, the piston and the side wall.
14. Piston machine according to claim 1, wherein the piston has cooling fins and/or is designed as a cavity.
15. Piston machine according to claim 1, further comprising a cooling device is provided for feeding the coolant through the opening of the housing and into the chamber.
16. Piston machine according to claim 1, wherein a size of the cooling opening is variably controlled or adjusted, by a control member or slide or throttle valve, which is arranged in a housing wall.
17. Piston machine, comprising: a housing with a chamber which has a substantially circle sector-shaped cross-section, a pivotal piston which is designed as a pivoting element, is arranged in the housing and includes a first working surface, the housing and the piston define at least one first variable working chamber, a drive or output which is connected to the piston, an outlet which is arranged in the working chamber for discharging a working fluid, the housing having a cooling opening in at least one housing wall, said opening leading to the chamber at least for convectively cooling a side of the piston opposite the first working surface by a coolant, and a second housing wall, which is circular arc-shaped in cross section, being attached to the piston, being arranged on a radius smaller than a maximum radial length of the piston and in at least one pivot position of the piston engaging into a passage of a side wall, and a second variable working chamber being defined at least by the second housing wall, the piston, and the at least one housing wall.
18. Piston machine, comprising: a housing with a chamber which has a substantially circle sector-shaped cross-section, a pivotal piston which is designed as a pivoting element, is arranged in the housing and includes a first working surface, the housing and the piston define at least one first variable working chamber, a drive or output which is connected to the piston, an outlet which is arranged in the working chamber for discharging a working fluid, the housing having a cooling opening in at least one housing wall, said opening leading to the chamber at least for convectively cooling a side of the piston opposite the first working surface by a coolant, a size of the cooling opening being variably controlled or adjusted, by a control member or slide or throttle valve, which is arranged in said at least one housing wall.
Description
(1) Exemplary embodiments of the invention will be described in greater detail with reference to the attached drawings, wherein:
(2) FIG. 1 shows a view of a cross-section of a piston machine with a cooling opening in a circular arc-shaped wall;
(3) FIG. 2 shows a view of a cross-section of a piston machine with a cooling opening being located at the center of the circular arc-shaped wall;
(4) FIG. 3 shows a view of a cross-section of a piston machine with a cooling opening in a rear wall;
(5) FIG. 4 shows a view of a cross-section of a piston machine with a cooling opening which is provided at the center in the rear wall;
(6) FIG. 5 shows a view of a cross-section of a piston machine with a cooling opening in a side wall;
(7) FIGS. 6a to 6c show views of a cross-section of a piston machine with two cooling openings in different walls;
(8) FIG. 6d shows a view of a cross-section of a piston machine with a second circular arc-shaped wall being attached to the piston;
(9) FIGS. 7a to 7c show a view of a cross-section of a piston machine with two pistons being arranged in a common housing, wherein a cooling opening is each arranged in each side wall of the housing;
(10) FIGS. 8a to 8c show a view of a cross-section of a piston machine with two pistons being arranged in a common housing, wherein an opening is each provided in each arc-shaped wall;
(11) FIGS. 9a to 9b show a view of a cross-section of two piston machines with respectively two pistons being arranged in a common housing, wherein a cooling opening is each provided in each side wall and in each circular arc-shaped wall;
(12) FIG. 10 shows a view of a cross-section of a piston machine according to prior art;
(13) FIGS. 11a and 11b show a view of a cross-section of another piston machine according to prior art and
(14) FIG. 12 shows a side view of a cross-section of the piston machine according to FIG. 11, which is illustrated with a drive.
(15) In the figures, recurring features are furnished with same reference numerals.
(16) In the following, reference is firstly made to FIG. 10. FIG. 10 shows a piston machine according to prior art of DE 10 2008 040 574 A1, which forms part of the present application.
(17) As illustrated in FIG. 10, the piston machine comprises a housing 1 which encloses a chamber 2, a bearing housing 3 and a crankcase 4. The chamber 2 has a circle sector-shaped cross-section and, according to the shape of a cylinder sector, is delimited by two side walls 5, 6, which are disposed at an angle of approx. 53 with respect to each other, of a front end wall (not shown) and a rear end wall 7 well as a wall 8 which is circular arc-shaped in cross-section and a rotary cylinder 9. A bearing housing 3 formed by two opposite bearing shells adjoins the ends of the side walls 5, 6 opposite the circular arc-shaped wall 8. Moreover, provision is made for a crankcase 4 being partly filled with an oil sump 12. The rotary cylinder 9 being rotatable about a rotation axis 14 is mounted in the bearing housing 13. The chamber 3 is hermetically sealed towards the crankcase 4, for instance with sealing strips 13 being integrated in the bearing housing 3. A piston 15 being formed as a pivot plate and a connecting rod 16, which are disposed diagonally opposite to each other, are rigidly or integrally formed at the rotary cylinder 9. The connecting rod 16 has a guide groove 17 which extends over the entire length thereof and into which a crank pin 18 of a crank shaft 19, which is rotatably mounted in the crankcase 4, engages. The piston 15, which is typically designed as a cavity, is located in the working chamber 2 and with an upper edge 28 sealingly rests against an inner surface of the curved circular arc-shaped wall 8. The upper edge 28 of the piston 15 is circular arc-shaped in cross-section and is defined by a center angle of approx. 8. Inlet valves 22, 24 and outlet valves 23, 25 are each formed in both side walls 5, 6 of the chamber 2. A pivot movement of the piston 15 defines a pivot plane, wherein the rear end wall 7 and the front end wall are parallel to the pivot plane. Of course, the abovementioned angles and can also be larger or smaller than those shown in the example.
(18) The above described piston machine can operate as a piston pump or piston compressor as follows, but can also function as an internal combustion engine, the function thereof being not described here, with inner or outer combustion: During rotary movement of a crank shaft 19, a crank pin 18 moving on a crank radius 11 slides in a guide groove 17 of a connecting rod 16 which thereby transmits a pivot movement to the piston 15. When a pivot movement of the piston 15 is performed from the position as shown in FIG. 10 at the left side wall 5 of the chamber 2 to the right side wall 6, the left inlet valve 22 and the right outlet valve 25 are open, while the left outlet valve 23 and the right inlet valve 24 are closed. Thus, a previously drawn in fluid is discharged from the chamber 2 via the right outlet valve 25. On the other side, a working fluid is drawn in via the left inlet valve 22, which is discharged again upon further rotary movement of the crank shaft 19 when the left inlet valve 22 is closed and the left outlet valve 23 is open, while on the right side fluid is drawn in via the inlet valve 24.
(19) The piston 15 thus operates as a twin-piston with two working surfaces 29 and 30, which executes two pivot movements during one turn of the crank shaft 19, this means from the left dead center at the left side wall 5 to the right dead center at the right side wall 6 and back. The oil sump 12 effects lubrication of the crank mechanism, this means the guide groove 17 and the crank pin 18 sliding therein, which, incidentally, can also be formed with rolling bearings and sliding blocks.
(20) As is known from DE 2008 040 574 A1, the guide groove 17 can also be arranged in the piston 15. Thus, a highly compact design can be realized.
(21) Alternatively, it can also be provided that the crank pin 18 of the crank shaft 19 engages in a connecting rod eye of a connecting rod which is articulately connected to the piston. The drive and output of the piston machine thus is not limited to the illustrated embodiments.
(22) FIG. 1 differs from FIG. 10 in that the housing 1 has a cooling opening 15 in the circular arc-shaped wall 8, said opening leading to the chamber 2. Moreover, in contrast to the embodiment of FIG. 10, inlet and outlet valves are not provided in the side wall 6. A coolant, in the illustrated example being air, flows through the cooling opening 51 into the chamber 2 and cools the same. Moreover, the piston 15 is convectively cooled by the air at least at a side 32 opposite the working surface 30. The piston machine of FIG. 1 for instance is designed as compressor and the cooling with the aid of the cooling opening makes it possible to increase efficiency of the compressor. Optionally, as shown in FIG. 1, provision can be made for a second cooling opening 51 in the side wall 6. Said second cooling opening for instance is designed as a coolant outlet through which the coolant can be discharged. In the figure, a flow direction of the coolant is indicated by arrows. This makes it possible to further enhance the flushing process and the cooling process. The piston machine of FIG. 2 differs from the exemplary embodiment of FIG. 10 in that a cooling opening 52 is provided at the center of the circular arc-shaped wall 8. While in the embodiment according to FIG. 1 two work cycles, namely drawing in and compressing, are possible during one turn of the crank shaft 10, in the embodiment according to FIG. 3, four work cycles are possible. The central formation of the cooling opening 52 makes it possible to alternately flush the working chamber 2 with coolant on the left and on the right-hand side. As a function of the pivot position of the piston 15, the working chamber 2 opens or the working chamber 2 closes. The cooling opening 52 in the circular arc-shaped wall 8 is defined both in FIG. 1 and in FIG. 2 by a center angle which is smaller than a pivot angle of the piston 15. In FIGS. 1 and 2 the opening 51 and 52 in the circular arc-shaped wall 8 extends over en entire axial length of the circular arc-shaped wall 8. This means the opening 51 and 52 is formed as an elongate groove in the circular arc-shaped wall and extends from the front end wall to rear end wall 7. Alternatively, the cooling opening 51 and 52 can have a smaller axial length.
(23) FIG. 3 differs from FIG. 10 in that a cooling opening 53 is arranged in the rear end wall 7. Moreover, in contrast to the embodiment of FIG. 10, inlet and outlet valves are not provided in the side wall 6. Moreover, the piston 15 has only one working surface 30.
(24) The embodiment of FIG. 1 differs from the embodiment of FIG. 10 in that a cooling opening 54 is arranged at the center in the rear end wall 7. As is the case in FIG. 2, the opening 54 is also arranged at the center here. While the piston 15 closes the opening 53 of FIG. 3 at the right side wall 6 when the piston 15 is in a pivot position, the piston 15 closes the opening 54 when the piston is in a central position in FIG. 4. Both the opening 53 of FIG. 3 and the opening 54 of FIG. 4 extend over an entire radial length of the end wall 7 from the bearing housing 3 to the circular arc-shaped wall 8. In both embodiments, the opening 53 and 54 is also provided in the front end wall (not shown). Only one opening 53 and 54 can be provided in the front end wall or in the rear end wall 7.
(25) While the piston 15 of FIGS. 1 and 3 has only one working surface 30, the piston 15 of FIGS. 2 and 4 has a second working surface 29 besides a first working surface 30. The cooling opening 52 and 54 of FIGS. 2 and 4 separates a first working chamber from a second working chamber. Moreover, the circular arc-shaped wall 8 of FIG. 2 and the end wall 7 of FIG. 4 are divided into two parts by the cooling opening 52 and the cooling opening 54, respectively.
(26) The piston machine of FIG. 5 differs from the embodiment of FIG. 10 in that a cooling opening 55 is provided in the side wall 6. Moreover, in contrast to the embodiment of FIG. 10, inlet and outlet valves are not provided in the side wall 6. In this way, the piston 15 has only one working surface 30. The cooling opening 55 in the side wall 6 extends over an entire radial and axial length of the side wall 6, i.e. in the embodiment of FIG. 5 the entire side wall 6 has been omitted. Thus, continuous convective cooling of the piston 15 is possible at a side 32 opposite the working surface. In contrast to FIGS. 1 to 4, the variable working chamber of FIG. 5 is closed in every pivot position of the piston 15.
(27) The embodiment of FIG. 6a differs from the embodiment of FIG. 10 in that the side wall 6 is completely omitted and that an opening 51 is further provided in the circular arc-shaped wall 8. Moreover, in contrast to the embodiment of FIG. 10, inlet and outlet valves are not provided in the side wall 6 and the piston 15 has only one working surface 30. The embodiment of FIG. 6a thus represents a mixture of FIGS. 5 and 1. The circular arc-shaped wall 8 of FIG. 6a defines a second center angle of approx. 25, which is smaller than the above described pivot angle of the piston 15. The opening 51 in the circular arc-shaped wall 8 is defined by the center angle . In FIG. 6a, the angles and are equal. However, in other embodiments they may also differ from one another. Hence, the center angle can also be larger or smaller than the center angle .
(28) In the embodiment of FIG. 6b, a cooling opening 52 and 54 is each provided in the circular arc-shaped wall 8 and in the rear end wall 7. The embodiment of FIG. 6b hence represents a mixture of the embodiments of FIGS. 2 and 4. In contrast to the embodiment of FIG. 4, the cooling opening 54 of the rear end wall 7, however, does not extend over an entire radial length of the end wall 7, but approximately up to one third of the radial length of the end wall 7. The coolant is introduced into the chamber 2 through the cooling opening 52, which is formed as coolant inlet, in the circular arc-shaped wall 8 using a blower 60. Subsequent to efficient flushing of the chamber 2, the coolant is then discharged from the chamber 2 through the cooling opening 54, which is formed as a coolant outlet, in the rear end wall 7. Here, the flow direction of the coolant is indicated by arrows. Thus, in this embodiment, the chamber 2 can be flushed particularly well by means of the coolant. In addition, a cooling opening can be provided in the front end wall (not shown).
(29) In the embodiment of FIG. 6c provision is each made for a cooling opening 54 and 54 in the rear end wall 7 and in the front end wall. A projection of the cooling opening 54 of the front end wall to the rear end wall 7 is indicated by dashed lines in FIG. 6c. Similarly to the embodiment of FIG. 6b, coolant is introduced into the chamber 2 through the cooling opening 54, which is designed as a coolant inlet, in the front end wall using an optional blower (not shown). Subsequent to efficient flushing and cooling of the chamber 2, the coolant is then discharged from the chamber 2 through the cooling opening 54, which is designed as a coolant outlet, in the rear end wall 7. Here, the flow direction of the coolant is indicated by an arrow. Hence, in this embodiment, the chamber can be flushed particularly well by means of the coolant. Of course, the flow direction can also be reversed. In this case, the blower blows the coolant through the cooling opening 54 of the rear end wall into the chamber 2. The coolant exits the chamber 2 through the cooling opening 54 in the front end wall after flushing of the chamber 2.
(30) As can be seen from FIGS. 1, 2, 4 and 6, the variable working chamber is closed or open as a function of the pivot position of the piston.
(31) The piston machine of FIG. 6d differs from the embodiment of FIG. 10 in that a cooling opening 55 is provided in the side wall 5. Moreover, a second wall 70, which is circular arc-shaped in cross-section, is attached to the piston 15 and is arranged on a smaller radius than a maximum radial length of the piston 15, and engages in the cooling opening 55 of the side wall 5. In this way, continuous convective cooling of the second circular arc-shaped wall is effected. The cooling opening 55 which is equally formed as a passage for the second circular arc-shaped wall 70 is provided above the second circular arc-shaped wall 70, viewed from the pivot axis 14. As a matter of course, it can also be arranged below the second circular arc-shaped wall 70. A second variable working chamber is defined by the second circular arc-shaped wall 70, the piston 15, the side wall 5, the front wall and the rear wall 7 and is sealingly closed by said walls. Hence, in the embodiment of FIG. 6d, there are two variable working chambers which are closed in each pivot position of the piston 15, whereby for instance two-stage compression can be realized.
(32) FIGS. 1-6d further differ from FIG. 10 in that a size of the cooling openings 51, 51, 52, 53, 54 and 55 can each be variably controlled or adjusted using a slide 61, 61, 62, 63, 64 and 65 being arranged in a respective housing wall. The slide 61, 61, 62, 63, 64 and 65 permits flush closure of the chamber 2 and in each case is connected to an electronic control device (not shown), which is further connected to a pressure sensor and temperature sensor (not shown) being arranged in the piston 15. The control device is adapted to control the slide 61, 61, 62, 63, 64 and 65 so as to control the size of the cooling opening 51, 51, 52, 53, 54 and 55 during operation of the piston machine and to enlarge or reduce it as required. At the time when a threshold of a temperature and/or pressure in the chamber 2 is reached, the cooling opening 51, 51, 52, 53, 54 and 55 can be opened or closed to cool the piston 15 and/or the chamber 2 or the size thereof can be enlarged or reduced. If the temperature measured at the piston 15 for instance is less or more than a specific threshold, the cooling opening 51, 51, 52, 53, 54 and 55 can be closed or opened so as to increase a feed volume of the piston machine. Thus, feed volume, coolant flow rate, pressure and temperature can be influenced during operation of the piston machine, so as to enhance efficiency of the piston machine. Alternatively, the slide 61, 61, 62, 63, 64 and 65 can be operated using a mechanical control device, for instance a camshaft, to open or close the cooling opening 51, 51, 52, 53, 54, 55 to a more or lesser degree. Instead of the slide 61, 61, 62, 63, 64 and 65 provision can also be made for a throttle valve or other control member.
(33) Unlike the piston machine according to FIG. 10, in the embodiments of FIGS. 1, 3, 5, 6a and 6d cooling fins 31 are provided on a side 32 of the piston 15 opposite the working surface 30 to enhance cooling. Furthermore, in order to improve the cooling effect, in each of the embodiments of FIGS. 1-6 provision is made for an optional blower 60 or a cooling device (not shown in FIGS. 3, 4, 6c, 7, 8 and 9) which blows air or any other coolant into the cooling opening 51, 52, 53, 54 and 55 as required. The blower 60 is equally connected to the abovementioned control device. The blower 60 is controlled by the control device in particular if the slide 61, 62, 63, 64 and 65 opens or closes the respective opening 51, 52, 53, 54 and 55. If a cooling device is not provided, the coolant can be drawn in by the motion of the piston through the cooling opening 51, 52, 53, 54 and 55. In order to further increase the cooling air flow rate, provision can be made for a Venturi pipe in the cooling air inlet opening shown in the figures. In order to enhance the cooling effect, cooling fins can be provided on the outer surface of the housing.
(34) Hereinafter, reference is made to FIGS. 11A, 11B and 12. In FIGS. 11A, 11B and 12 views of cross-sections of a piston machine according to prior art of DE 10 2010 036 977 B3 are shown, which equally forms part of the present application.
(35) According to FIGS. 11A, 11B and 12, pistons 101 and 102 are connected to a rotary cylinder 106 which is rotatably mounted in a housing 103 about a rotation axis 104 via a bearing 105, and at an end side each have a guide groove 107 into which a crank pin 108 of a crank shaft 110 being connected to a driveshaft 109 engages. The guide groove 107 functions as a connecting rod loop or piston loop, which thus forms an integral part of the pistons 101 and 102. The two crank shafts 110 interacting with the respective piston 101 and 102, as shown in FIG. 12, are connected to each other via a gear mechanism 126 and are synchronized in such a manner that the pistons 101 and 102 can be driven in a respectively parallel opposite direction and can be moved in the housing parts 103a and 103b which are designed in the form of a cylinder sector (segment).
(36) The integrally formed housing 103 comprisesindicated by a dashed line Xtwo joined housing parts 103a, 103b which, however, are turned by 180 and have a substantially circle sector-shaped cross-section, in which the rotary cylinders of the pistons 101 and 102 are once mounted at the upper housing wall 111 and once at the lower housing wall 112. A chamber A1 and A2 enclosed by the housing thus has the shape of two equisized circle sectors which lie side-by-side so as to be opposed to each other. The housing 103 further comprises a housing rear wall 114 and a housing cover 113 as well as a first side wall 115 and a second side wall 116. The two twin-pistons 101, 102, which are aligned in parallel to one another in every position, are disposed in an initial position, as shown in FIG. 11A, at the respective side wall 115, 116 and in the end position at the separating line X nearly abut against a defined gap. Inlet valves 18a, 18b and 18c as well as outlet valves 19a, 19b and 19c are arranged in the two side walls 115 and 116 and in the housing rear wall 114 at the height of the separating line X. By means of a synchronous but oppositely directed rotary movement of the two crank pins 108 according to arrow 17a, 17b, the two pistons 101 and 102 are moved towards one another close to the separating line X and are moved away from one another close to the side walls 115 and 116. Use can also be made of just one crank shaft, wherein the pistons 101 and 102 are synchronized for instance by a gearwheel. The piston machine according to FIG. 11 designed in this way can be operated for instance as a compressor, pump or engine/motor.
(37) For instance, in case of the function as a pump, a feed medium, which is located in the inner large working chamber A3 between the two twin-piston plates 101 and 102 and which has been previously drawn in via the inlet valve 18c, is discharged from the working chamber A3 again during the pivot movement of the twin-piston plates 101 and 102 toward the separating line X. During this pivot movement (discharge), a feed medium is simultaneously drawn into the two outer (smaller) working chambers A1 and A2, which are each formed between the twin-piston plates 101 and 102 and the side walls 115 and 116, via the inlet valves 18a and 18b. When the two twin-piston plates 101 and 102 subsequently move in the direction of the side walls 115 and 116, the feed medium, which has been previously drawn into the working chambers A1 and A2, is discharged through the outlet valves 19a, 19b and at the same time, feed medium is drawn into the large working chamber A3 via the inlet valve 18c. In this way, efficient feed operation is ensured with the aid of two interacting twin-piston plates 101 and 102 and three working chambers A1, A2 and A3 in one and the same housing 103. The maximum volume of the two small outer working chambers A1 and A2 corresponds to the maximum volume of the larger inner working chamber A3. The above-described piston machine can be operated as a compressor or expansion motor or as a combination thereof with equally high efficiency. For instance, the medium-largeworking chamber A3 can operate as an expansion motor, while the two outer smallerworking chambers A1 and A2 operate as compressor or pump and are driven by the expansion motor. When the described piston pump is used as a compressor, the inner working chamber A3 and an outer (left) working chamber A1 can be operated as a first compressor stage, and the other outer working chamber A2 can be operated as second compressor stage. Hence, the working chambers A1, A2 and A3 can each fulfil different functions as compressor, pump and engine/motor.
(38) The embodiment of FIGS. 7A-7C differs from the embodiment of FIG. 11 in that cooling openings 151 are provided in the side walls 15 and 16, wherein the cooling openings 151 in the side walls 115 and 116 extend over an entire radial and axial length of the side walls 115 and 116. The cooling openings 151 make it possible to at least convectively cool the pistons 101 and 102 at a piston side opposite the working surface of the piston by means of a coolant. Besides, the embodiments of FIGS. 7a to 7c are similar to the embodiment of FIG. 5. Instead of two cooling openings 151, as can be seen in FIGS. 7a-c, a cooling opening 151 can also be provided in only one of the side walls 115 and 116. In this case, only one piston 101, 102 is cooled.
(39) The embodiment of FIGS. 8A-8C differs from the embodiment of FIG. 11 in that two cooling openings 152 are provided in the circular arc-shaped wall. Just like in FIG. 11, the embodiment of FIG. 8 also comprises three working chambers A1, A2 and A3. A particularly good cooling effect can be attained in the working chamber A3, since the cooling openings 152 are arranged opposite one another. A coolant, for instance air, thus is allowed for instance to flow in and out from the one side to the other side, what is indicated in FIG. 8 using arrows 130 and 131. The cooling openings 152 thus make it possible to cool the working chambers A1, A2 and A3 and the pistons 101 and 102 at least convectively by means of a coolant. The cooling opening 152 here is designed as large as an upper edge 140 of the pistons 101 and 102. The cooling opening 152, however, can also be smaller or larger than the upper edge 140 of the pistons 101 and 102. As can be seen from FIG. 8b, there is a pivot position, in which all working chambers A1, A2 and A3 are closed. In the pivot position of FIG. 8c, the working chambers A1 and A2 are opened, while in the pivot position of FIG. 8a, the working chamber A3 is largely open. Besides, the arrangement of the cooling openings 152 in FIG. 8 is similar to the embodiment of FIG. 2. Alternatively, provision can also be made here for only one cooling opening 152 instead of two cooling openings 152.
(40) In FIGS. 9a and 9b with respect to cooling openings 151 and 152 mixtures of FIGS. 7 and 8 are shown in analogy with the embodiment of FIG. 6a. In FIG. 9a, the wall, which is circular arc-shaped in cross-section, is formed by two parts 111 and 111 and 112 and 112, respectively, which are radially disposed at different positions. There is a radial gap 140 between the upper edge 140 of the piston and the circular arc-shaped housing wall 111 and 112. Said radial gap 140 in the pivot direction extends over a center angle , and in axial direction extends from the housing cover 113 to the housing rear wall 114. The dimensions of the gap 140 can be varied depending on the embodiment in radial direction, in axial direction or in pivot direction. In FIG. 9b, the circular arc-shaped walls 111 and 112 are merely as large as the upper edge 140 of the piston 101 and 102. Alternatively, the dimensions of the circular arc-shaped wall 111 and 112 can be smaller or larger. In contrast to the embodiment of FIG. 8, in FIGS. 9a and 9b there is only one working chamber A3. In the embodiments of FIGS. 9a and 9b, the piston 101 and 102 can be convectively cooled from several sides. Hence, loss of chamber volume is compensated in FIGS. 9a and 9b by an increased cooling effect.
(41) FIGS. 7-9 further differ from FIG. 11 in that a size of the cooling openings 151 and 152 can be variably controlled or adjusted using a slide (not shown) which is arranged in a corresponding housing wall. Said slide allows flush closure of the chamber and is in each case connected to an electronic control device (not shown) which is further connected to a pressure sensor end temperature sensor (not shown) which are arranged in the piston 101 and 102. The control device is adapted to control the slide so as to regulate or change the size of the cooling opening during operation of the piston machine. At the time when a threshold of a temperature and/or pressure is reached in the chamber, the cooling opening 151 and 152 can be opened or closed to a more or lesser degree to cool the piston 101 and 102 and/or the chamber. If the temperature measured at the piston 101 and 102 for instance is less or more than a specific threshold, the cooling opening 151 and 152 can be closed or opened to increase a feed volume of the piston machine. Hence, feed volume, coolant flow rate, pressure and temperature can be influenced during operation of the piston machine, to enhance efficiency of the piston machine. Alternatively, the slide can also be operated using a mechanical control device, for instance a camshaft, to open or close the cooling opening 151 and 152 to a more or lesser degree. Instead of the slide, for instance a throttle valve or other control member can also be provided.
(42) Moreover, an optional blower or a cooling device is each provided in the embodiments of FIGS. 7-9 (not shown in FIGS. 7, 8 and 9), which draws air or other coolant into the cooling opening 151 and 152 as required, to improve the cooling effect. The blower is also connected to the abovementioned control device. The blower is controlled by the control device in particular if the slide opens or closes the respective opening 151 and 152. If a cooling device is not provided, the coolant can be drawn in through the cooling opening 151 and 152 by the motion of the piston. In order to further enhance the cooling air flow rate, a Venturi pipe can be provided at the cooling air inlet opening which is shown in the figures. Cooling fins can be provided on the outer surface of the housing to increase the cooling effect.
(43) The embodiments in FIGS. 7A to 9B can be broadened as desired by further housing parts, which are arranged side by side, but turned by 180 with respect to one another, and which have twin-piston plates.
(44) The drive or output of the piston machine is not limited to the illustrated embodiments of FIGS. 1 to 9B. For instance, it can be provided that the crank pin of the crank shaft engages in a connecting rod eye of a connecting rod being articulately connected to the piston.
(45) The features disclosed in the exemplary embodiments of the different embodiments can be combined and can be claimed individually.
(46) TABLE-US-00001 List of reference numerals 1 housing 55 cooling opening 2 working chamber 60 blower 3 bearing housing 61 slide 4 crankcase 61 slide 5 left side wall 62 slide 6 right side wall 63 slide 7 end wall 64 slide 8 circular arc-shaped wall 65 slide 9 rotary cylinder 70 circular arc-shaped wall 10 bearing shells 101 piston 11 crank radius 102 piston 12 oil sump 103 housing 13 sealing strips 103a housing part 14 pivot axis 103b housing part 15 piston 104 rotation axis 16 connecting rod 105 bearing 17 guide groove 106 rotary cylinder 18 crank pin 107 guide groove 19 crank shaft 108 crank pin 22 left inlet valve 109 drive shaft 23 left outlet valve 110 crank shaft 24 right inlet valve 111 housing wall 25 right outlet valve 111 circular arc-shaped wall 28 upper edge piston 111 circular arc-shaped wall 29 working surface 112 housing wall 30 working surface 112 circular arc-shaped wall 31 cooling fins 112 circular arc-shaped wall 32 piston side 113 housing cover 51 cooling opening 114 housing rear wall 51 cooling opening 115 first side wall 52 cooling opening 116 second side wall 53 cooling opening 17a motion crank pin 54 cooling opening 17b motion crank pin 54 cooling opening 18a inlet valve 18b inlet valve 18c inlet valve 160 gap 19a outlet valve pivot angle of piston 19b outlet valve center angle 19c outlet valve center angle 130 flow direction center angle 131 flow direction center angle 140 upper edge piston A1 working chamber 151 cooling opening A2 working chamber 152 cooling opening A3 working chamber
