Gerotor hydraulic device with adjustable output

Abstract

A hydraulic device (1) comprising a housing (2) and a gerotor (3) contained within the housing (2), the gerotor (3) having an inner rotor (4) eccentrically disposed within an outer ring (5), the outer ring having a central axis (19), the outer ring (5) being fixed to the housing, the inner rotor (4) having external lobes (4a) extending radially outwardly engaging the outer ring (5) having internal lobes (5a) extending radially inwardly, the inner rotor (4) being arranged for orbital and rotational movement relative the outer ring (5), wherein the orbital and rotational movement will define a plurality of expanding and contracting volume pressure chambers (7) between the inner rotor (4) and the outer ring (5). The hydraulic device (1) comprises a fluid feeder tube (8) with a central axis (19), the fluid feeder tube (8) is provided with at least one fluid inlet line (8a, 8c) and at least one fluid outlet line (8b, 8d), the inner rotor (4) is adapted to slide against a drive shaft cylinder (10b), the drive shaft cylinder (10b) having a circumference which is eccentrically disposed relative the central axis (19), the inner rotor (4) comprises at least one radial fluid feeder channel (9) disposed radially from the center of and through the inner rotor (4) and out to at least one of the plurality of expanding and contracting volume pressure chambers (7), wherein said fluid inlet line (8a, 8c) and said fluid outlet line (8b, 8d) respectively are radially connectable to said radial fluid feeder channel (9) for fluid communication into and out from said expanding and contracting volume pressure chambers (7).

Claims

1. A hydraulic device comprising: a housing; and a gerotor contained within the housing, the gerotor having an inner rotor eccentrically disposed within an outer ring; wherein the outer ring has a central axis, the outer ring being stationary and fixed to the housing; the inner rotor having external lobes extending radially outwardly engaging the outer ring having internal lobes extending radially inwardly, the inner rotor being arranged for orbital and rotational movement relative the outer ring, wherein the orbital and rotational movement will define a plurality of expanding and contracting volume pressure chambers between the inner rotor and the outer ring; wherein the hydraulic device comprises a fluid feeder tube with a central axis common with the central axis of the outer ring, the fluid feeder tube is provided with at least one fluid inlet line and at least one fluid outlet line; the inner rotor slides against a drive shaft cylinder, the drive shaft cylinder is connected to a drive shaft that has an axis of rotation aligned with the central axis of the outer ring, the drive shaft cylinder having a circumference which is eccentrically disposed relative the central axis of the outer ring, the inner rotor comprises at least one radial fluid feeder channel disposed radially from the centre of and through the inner rotor and out to at least one of the plurality of expanding and contracting volume pressure chambers; wherein said fluid inlet line and said fluid outlet line respectively are radially connectable to said at least one radial fluid feeder channel for fluid communication into and out from said expanding and contracting volume pressure chambers; and wherein flow though through the at least one fluid inlet line is in an opposite direction from flow through the at least one fluid outlet line.

2. A hydraulic device according to claim 1, wherein the hydraulic device comprises fluid regulating means comprising fluid openings selectively connecting and disconnecting said fluid inlet line and said fluid outlet line to said at least one radial fluid feeder channel.

3. A hydraulic device according to claim 1, wherein said at least one radial fluid feeder channel is disposed between the external lobes of the inner rotor.

4. A hydraulic device according to claim 1, wherein the at least one radial fluid feeder channel comprises four radial fluid feeder channels disposed between each of the external lobes of the inner rotor.

5. A hydraulic device comprising: a housing; and a gerotor contained within the housing, the gerotor having an inner rotor eccentrically disposed within an outer ring; wherein the outer ring has a central axis, the outer ring being fixed to the housing; the inner rotor having external lobes extending radially outwardly engaging the outer ring having internal lobes extending radially inwardly, the inner rotor being arranged for orbital and rotational movement relative the outer ring, wherein the orbital and rotational movement will define a plurality of expanding and contracting volume pressure chambers between the inner rotor and the outer ring; wherein the hydraulic device comprises a fluid feeder tube with a central axis common with the central axis of the outer ring, the fluid feeder tube is provided with at least one fluid inlet line and at least one fluid outlet line; the inner rotor slides against a drive shaft cylinder, the drive shaft cylinder having a circumference which is eccentrically disposed relative the central axis, the inner rotor comprises at least one radial fluid feeder channel disposed radially from the centre of and through the inner rotor and out to at least one of the plurality of expanding and contracting volume pressure chambers, wherein said fluid inlet line and said fluid outlet line respectively are radially connectable to said at least one radial fluid feeder channel for fluid communication into and out from said expanding and contracting volume pressure chambers; wherein the hydraulic device comprises fluid regulating means comprising fluid openings selectively connecting and disconnecting said fluid inlet line and said fluid outlet line to said at least one radial fluid feeder channel; wherein the fluid regulating means comprises the fluid feeder tube, an inner control sleeve and an outer control sleeve, and the drive shaft cylinder; and wherein the inner control sleeve and the outer control sleeve are selectively and separately positionable relative to the drive shaft cylinder to selectively connect and disconnect said fluid inlet line and said fluid outlet line to said at least one radial fluid feeder channel, to regulate flow between said at least one radial fluid feeder channel, and said fluid inlet line and said fluid outlet line.

6. A hydraulic device according to claim 5, wherein the inner control sleeve and the outer control sleeve are provided between the fluid feeder tube and the inner rotor; wherein the inner control sleeve and the outer control sleeve are selectively displaceable and arranged to radially connect said fluid inlet line and said fluid outlet line to said at least one radial fluid feeder channel to regulate radial fluid feed through the inner rotor to said expanding and contracting volume pressure cambers.

7. A hydraulic device according to claim 5, wherein the inner control sleeve comprises inner fluid openings and the outer control sleeve comprises outer fluid openings adapted to connect and disconnect said fluid inlet line and said fluid outlet line to said at least one radial fluid feeder channel.

8. A hydraulic device according to claim 5, wherein the inner and outer control sleeves are displaceable around the fluid feeder tube.

9. A hydraulic device according to claim 5, wherein the inner and outer control sleeves are displaceable to a first position in which said fluid inlet line is closed.

10. A hydraulic device according to claim 5, wherein the inner and outer control sleeves are displaceable to a second position in which a first fluid inlet opening is open to said fluid inlet line.

11. A hydraulic device according to claim 5, wherein the inner and outer control sleeves are displaceable to a third position in which a second fluid inlet opening is open to said fluid inlet line.

12. A hydraulic device according to claim 5, wherein the inner and outer control sleeves are displaceable to a fourth position in which a first fluid inlet opening and a second fluid inlet opening are open to said fluid inlet line.

13. A hydraulic device according to claim 5, wherein a drive shaft unit comprises a drive shaft extending from the drive shaft cylinder and having an axis of rotation aligned with the central axis of the outer ring; wherein the drive shaft cylinder is provided between the fluid feeder tube and the inner rotor, the drive shaft cylinder having a circumference which is eccentrically disposed relative the central axis; wherein the drive shaft cylinder is arranged to radially connect said fluid inlet line and said fluid outlet line to said at least one radial fluid feeder channel to allow for a regulated radial fluid feed through the inner rotor to said expanding and contracting volume pressure cambers.

14. A hydraulic device according to claim 5, wherein the drive shaft cylinder is provided with at least one drive shaft cylinder opening to allow for a regulated radial feed through the inner rotor to said expanding and contracting volume pressure cambers.

15. A hydraulic device according to claim 5, wherein the fluid feeder tube comprises at least one feeder tube fluid opening to allow for a radial fluid feed between said fluid inlet line and said fluid outlet line through the inner rotor to said expanding and contracting volume pressure cambers.

16. A hydraulic device according to claim 5, wherein the fluid feeder tube comprises at least one fluid inlet port and at least one fluid outlet port to allow for a radial inlet and outlet feed of fluid.

17. A hydraulic device according to claim 5, wherein the fluid feeder tube is fixed to the housing.

18. A hydraulic device according to claim 5, wherein said fluid inlet line and said fluid outlet line in the fluid feeder tube are symmetrical.

19. A hydraulic device according to claim 5, wherein the at least one fluid inlet line of the fluid feeder tube comprises two fluid inlet lines, and wherein the at least one fluid outlet line of the feeder tube comprises two fluid outlet lines.

20. A hydraulic device according to claim 5, wherein the inner control sleeve and the outer control sleeve are arranged to cooperate with the fluid feeder tube, the drive shaft cylinder and said at least one radial fluid feeder channel to define a fluid recirculation region.

21. A hydraulic device according to claim 5, wherein the hydraulic device is a hydraulic motor.

22. A hydraulic device according to claim 5, wherein the hydraulic device is a hydraulic pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be described in detail with reference to the figures, wherein:

(2) FIG. 1 shows a schematically exploded view of a hydraulic device according to the invention.

(3) FIG. 2 shows a schematically cross section view of a hydraulic device according to the invention.

(4) FIG. 3 shows a schematically cross section view of a gerotor according to the invention.

(5) FIG. 4 shows a schematically cross section view of a fluid feeder tube according to the invention.

(6) FIG. 5 shows a schematically exploded view of a fluid feeder tube and inner and outer control sleeves according to the invention.

(7) FIG. 6a shows a schematically view of a drive shaft cylinder according to the invention.

(8) FIG. 6b shows a schematically view of a drive shaft cylinder according to the invention.

(9) FIG. 6c shows a schematically view of a drive shaft cylinder according to the invention.

(10) FIG. 7 shows a schematically view of a fluid feeder tube and inner and outer control sleeves according to the invention.

(11) FIG. 8 shows a schematically cross section view of a gerotor according to the invention.

(12) FIG. 9a shows a schematically view of a first position of the inner and outer control sleeves.

(13) FIG. 9b shows a schematically view of a second position of the inner and outer control sleeves.

(14) FIG. 9c shows a schematically view of a third position of the inner and outer control sleeves.

(15) FIG. 9d shows a schematically view of a fourth position of the inner and outer control sleeves.

(16) It should be added that the following description of the examples is for illustration purposes only and should not be interpreted as limiting the invention exclusively to these examples/aspects.

DETAILED DESCRIPTION OF THE DRAWINGS

(17) Examples of the present invention relate, in general, to the field of rotary fluid devices, in particularly, to hydraulic devices comprising gerotors. The present invention relates to a hydraulic device arranged to regulate the effective pump or motor displacement of a hydraulic device by providing the ability to control and direct the fluid flow within the hydraulic device.

(18) Examples of the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which examples of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein. Rather, these examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference signs refer to like elements throughout.

(19) All the FIGS. 1 to 9d are schematically illustrated. FIG. 1 shows an example of the hydraulic device 1 according to the invention for directing and controlling the fluid flow. The present invention relates to an improved hydraulic device for directing and controlling the fluid flow to and from a plurality of volume pressure chambers within a gerotor.

(20) Referring to FIG. 1, the hydraulic device 1 comprises a housing 2 and a gerotor 3. The hydraulic device 1 further comprises an inner control sleeve 13 and an outer control sleeve set 14, a drive shaft unit 10 and a fluid feeder tube 8. The housing 2 comprises a front housing 2a and a rear housing 2b. The front housing 2a is mounted to the rear housing 2b by a plurality of bolts. However, the front housing 2a can be mounted to the rear housing by any conventional fastening means such as for example screws. The fluid feeder tube 8 is fixed to the rear housing 2b.

(21) The gerotor 3 comprises an inner rotor 4 and an outer ring 5. The inner rotor 4 is eccentrically disposed within the outer ring 5. The outer ring 5 has a central axis 19. The central axis 19 is aligned with the centre of the outer ring 5. The inner rotor is arranged to rotate in an orbital and rotational movement relative the outer ring 5. The inner rotor is arranged to rotate around its own axis which is eccentrically disposed relative the central axis 19 of the outer ring 5. The inner rotor 4 is arranged to rotate in an orbital movement around the central axis 19. The inner rotor 4 comprises external lobes extending radially outwardly. The outer ring 5 comprises internal lobes extending radially inwardly. Normally, the inner rotor 4 has one less external lobe than the outer ring 5.

(22) During rotation of the inner rotor 4, the external lobes of the inner rotor 4 remain in contact with internal lobes of the outer ring 5 as the inner rotor 4 moves relative to the outer ring 5. This movement results in a continuous multi-location contact between the inner rotor 4 and the outer ring 5 creating fluid volume pressure chambers that sequentially expand and contract as the inner rotor 4 have a rotational and orbital movement with respect to the outer ring 5 and the central axis 19.

(23) When the inner rotor 4 and its external lobes rotate, the volume pressure chambers between the inner rotor 4 and the outer ring 5 are varied causing the fluid to be compressed enabling the gerotor to act as a pump. Alternatively, a fluid may be forced into the volume pressure chamber between the inner rotor 4 and the outer ring 5 causing the gerotor to function as a motor, i.e. turning fluid flow pressure into mechanical rotation. The hydraulic device 1 is arranged to provide the ability to control the fluid flow through the gerotor 3 by providing for a radial fluid feed from the centre of the gerotor 3 through the inner rotor 4 and out to a volume pressure chambers between the inner rotor 4 and the outer ring 5. The hydraulic device 1 is arranged to provide the ability to partially recirculate the fluid flows and to regulate the effective pump or motor displacement by using the inner and outer control sleeves 13, 14.

(24) The drive shaft unit 10 comprises a drive shaft 10a and a drive shaft cylinder 10b. The drive shaft 10a extends from the front housing 2a and has an axis of rotation which is aligned with the central axis 19. The drive shaft cylinder 10b is eccentrically connected to the drive shaft 10a. The drive shaft cylinder has a radial displacement around the fluid feeder tube, wherein the drive shaft cylinder has a different radial extension around and from the central axis 19. A seal can be provided between the drive shaft 10 and the front housing 2a. The centre of the drive shaft cylinder 10b is offset relative the central axis 19. This offset may be adjustable. The drive shaft cylinder 10b is arranged to be mounted between a fluid feeder tube 8 and the inner rotor 4, more particularly the drive shaft cylinder 10b is arranged to be mounted between the outer control sleeve 14 and the inner rotor 4. The drive shaft cylinder 10b comprises at least one radial fluid opening 11. The drive shaft cylinder 10b comprises annular seals 44a, 44b at the sides of the drive shaft cylinder 10b in the interface towards the inner rotor 4.

(25) When the hydraulic device 1 functions as a motor, the rotation of the inner rotor 4 generated by the forced pressurized hydraulic fluid is output via the rotatable drive shaft 10a extending from the front housing 2a. A hydraulic motor can convert pressurized fluid flow into torque and speed for transferring rotational motion to a desired piece of machinery. When the hydraulic device 1 functions as a pump, the rotation of the inner rotor 4 is generated by the rotation of the drive shaft 10, i.e. mechanical energy is converted into to hydraulic fluid energy. The hydraulic device 1 may comprise flanges extending radially from both sides of the gerotor 3 providing stability to the hydraulic device 1. The hydraulic device 1 may comprise cam rings between the outer control sleeve and the drive shaft cylinder 10b. Whereby, these cam rings functions as seals.

(26) The hydraulic device 1 according to the invention may comprise several control sleeves. The inner and outer control sleeves 13, 14 are displaceable around the fluid feeder tube 8. The inner and outer control sleeves 13, 14 are arranged to be rotatable around the fluid feeder tube 8. The inner and outer control sleeves 13, 14 may be turned while the hydraulic device 1 is running. The amount of fluid flowing into the hydraulic device 1 may be varied while the hydraulic device 1 is running.

(27) FIG. 2 shows a cross section of an example of the hydraulic device 1 according to the invention for directing and controlling the fluid flow. FIG. 2 shows the outer ring 5 having internal lobes 5a, the inner ring 4 having external lobes 4a, the inner control sleeve 13 and the outer control sleeve 14. The drive shaft cylinder 10b and the inner control sleeve 13 and the outer control sleeve 14 are mounted in between the fluid feeder tube 8 and the inner rotor 4, more particularly the inner and outer control sleeves 13, 14 are arranged to be mounted between the drive shaft cylinder 10b and the fluid feeder tube 8. The drive shaft cylinder 10b and the inner control sleeve 13 and the outer control sleeve 14 are arranged and displaceable to radially connect the fluid feeder tube with the radial fluid feeder channels 9.

(28) The inner control sleeve 13 comprises an inner control sleeve end gear 15. The outer control sleeve 14 comprises an outer control sleeve end gear 16. By altering the inner control sleeve end gear 15 and the outer control sleeve end gear 16, the inner and outer control sleeves 13, 14 are rotated around the fluid feeder tube 8 regulating the fluid flow. The inner and outer control sleeves 13, 14 can be turned by an electric motor (not shown), for example over a worm gear (not shown) connecting to the outer circumference of the inner and outer control sleeve end gears 15, 16.

(29) Referring to FIG. 2, four radial fluid feeder channels 9 are disposed between each of the external lobes 4a of the inner rotor 4. The size, shape and number of fluid feeder channels 9 between the external lobes 4a of the inner rotor 4 may be varied. Preferably, radial fluid feeder channels 9 are disposed between all of the external lobes 4a of the inner rotor 4. The inner rotor 4 may comprise one radial fluid feeder channel between all of the external lobes 4a. The radial fluid feeder channels may be square channels.

(30) The inner and outer control sleeves 13, 14 are arranged to cooperate with the fluid feeder tube 8, the drive shaft cylinder 10b and said radial fluid feeder channel 9 to define a fluid recirculation region 12.

(31) Referring to FIG. 2, orbital and rotational movement of the inner rotor 4 will define a plurality of expanding and contracting volume pressure chambers 7 between the inner rotor 4 and the outer ring 5.

(32) FIG. 3 shows a cross section of the gerotor 3 according to the invention for directing and controlling the fluid flow. The outer ring 5 has a central axis 19.

(33) The drive shaft cylinder 10b comprises a first vane 50a, a second vane 50b and a third vane 50c. The drive shaft cylinder 10b slides on the first vane 50a, the second vane 50b and the third vane 50c, which seals between the fluid feeder tube 8 and the inner rotor 4. The vanes 50a, 50b, 50c seals and as the drive shaft cylinder 10b rotates the vanes 50a, 50b, 50c seals and pushes the fluid between the inner rotor 4 and the drive shaft cylinder 10b in the rotation direction of the drive shaft cylinder 10b.

(34) The first vane 50a is the point on the drive shaft cylinder 10b which is furthest away from the central axis 19. The high pressure section of the plurality of expanding and contracting volume pressure chambers is located in front of the first vane 50a. The low pressure section is located behind the first vane 50a. Wherein in front of is in the direction of rotation of the central axis 19, and behind is in the opposite direction of the direction of rotation of the drive shaft unit 10. The third vane 50c is the point on the drive shaft cylinder 10b which is closest to the central axis 19, and the second vane 50b is between the first vane 50a and the third vane 50c.

(35) FIG. 3 shows an example according to the invention, where at a high pressurised vane volume 51b, between the second vane 50b and the third vane 50c, where the fluid flow from the inlet lines, the area between the drive shaft cylinder 10b and the inner rotor 4 correspond to a pressurized area between the inner rotor 4 and the outer ring 5. Whereby, all radial forces on the inner rotor 4 eliminate each other and only the forces on the drive shaft cylinder 10b and reaction forces on the outer ring 5 remain. It is the force on the drive shaft cylinder 10b that creates torque speed on the drive shaft 10a.

(36) FIG. 4 shows a cross section view of a fluid feeder tube 8 according to the invention having a central axis 19. The fluid feeder tube 8 comprises two fluid inlet lines 8a, 8c and two outlet lines 8b, 8d. Preferably, the fluid inlet lines 8a, 8c and the fluid outlet lines 8b, 8d are symmetrical. However, the fluid inlet lines 8a, 8c and the fluid outlet lines 8b, 8d may be non-symmetrical with each other.

(37) FIG. 5 shows an exploded view of a fluid feeder tube 8 and inner and outer control sleeves 13, 14 according to the invention. The fluid feeder tube 8 comprises radial fluid feeder tube openings 20a, 20b, 20c for the fluid outlet line 8b. These radial fluid feeder openings 20a, 20b, 20c for the fluid outlet line 8b have an axial displacement with each other. The fluid feeder tube 8 comprises radial fluid feeder tube openings 21a, 21b for the fluid inlet line 8a. These radial fluid feeder openings 21a, 21b for the fluid inlet line 8a have an axial displacement to each other. Preferably, the fluid feeder tube 8 comprises two fluid inlet lines 8a, 8c and two fluid outlet lines 8b, 8d. Referring to the example in FIG. 5, all fluid inlet lines 8a, 8c in the fluid feeder tube 8 comprise the same number and type of radial fluid openings. All fluid outlet lines 8b, 8d in the fluid feeder tube 8 comprise the same number and type of openings. However, the number of radial fluid openings in the fluid feeder tube 8 may be varied to achieve a desired number of gears for the hydraulic device 1.

(38) The fluid feeder tube 8 comprises at least one fluid inlet port 17 and at least one fluid outlet port 18a, 18b to allow for a radial inlet and outlet feed of fluid.

(39) The inner control sleeve 13 is arranged to be disposed around the fluid feeder tube 8. The inner control sleeve 13 comprises radial inner fluid openings 22a, 22b, 22c which are arranged to interact with openings in the fluid feeder tube 8 and the outer control sleeve 14. These radial inner fluid openings 22a, 22b, 22c have an axial displacement to each other. The inner control sleeve 13 comprises radial inner fluid openings 23a, 23b which are arranged to interact with openings in the fluid feeder tube 8 and the outer control sleeve 14. These radial inner fluid openings 23a, 23b have an axial displacement with each other.

(40) The outer control sleeve 14 is arranged to be disposed around the fluid feeder tube 8, more particularly around the inner control sleeve 13. The outer control sleeve 14 comprises radial outer fluid openings 24a, 24b, 24c which are arranged to interact with openings in the fluid feeder tube 8 and the inner control sleeve 13. These radial outer fluid openings 24a, 24b, 24c have an axial displacement to each other. The outer control sleeve 14 comprises radial outer fluid openings 25a, 25b which are arranged to interact with openings in the fluid feeder tube 8 and the inner control sleeve 13. These radial inner fluid openings 25a, 25b have an axial displacement with each other. The outer control sleeve 14 comprise annular seals 60, 61, 62, 63 on each side of the radial fluid openings of the inner and outer control sleeve 13, 14, provided such that the annular seals 60, 61, 62, 63 seals between the outer control sleeve 14 and the drive shaft cylinder 10b.

(41) The fluid can be pumped through the fluid inlet lines 8a, 8c and through the radial inner and outer fluid openings of the inner and outer control sleeves 13, 14 and the drive shaft cylinder openings and into the low pressure section of the expanding and contracting volume pressure chambers 7. When the fluid is displaced between the inner rotor 4 and the outer ring 5 to the high pressure section of the expanding and contracting volume pressure chambers 7, it will be pressed out through the radial fluid feeder channels 9 and into the fluid outlet lines 8c, 8d through drive shaft cylinder openings and through the radial inner and outer fluid openings of the inner and outer control sleeves 13, 14.

(42) Referring to FIG. 5, the fluid feeder tube 8, the inner and outer control sleeves 13, 14 comprise a plurality of fluid openings. These fluid openings may vary in size and shape. These fluid openings provide for a radial feed through the inner rotor 4 to the expanding and contracting volume pressure cambers 7.

(43) By rotating the inner and outer control sleeve 13, 14 the radial fluid feed can be controlled and directed from the fluid feeder tube 8 to the expanding and contracting volume pressure chambers 7 and then back to the fluid feeder tube 8. The inner and outer control sleeves 13, 14 are rotated relative each other to regulate the radial fluid flow in the hydraulic device 1.

(44) FIGS. 6a-6c show the drive shaft unit 10 comprising the drive shaft 10a and the drive shaft cylinder 10b. The drive shaft cylinder 10b comprise several radial fluid openings 11a, 11b, 11c, 11d, 11e and as the drive shaft cylinder 10b rotates, the drive shaft cylinder openings 11a, 11b, 11c, 11d, 11e will pass over the stationary radial fluid openings in the control sleeves 13, 14. The radial drive shaft cylinder openings 11a, 11b, 11c, and the radial drive shaft opening 11d and the radial drive shaft openings 11e have an axial displacement to each other. The drive shaft cylinder openings 11a, 11b, 11c, 11d, 11e are located in open compartments 45. FIG. 6c show the second vane 50b on the drive shaft cylinder 10b.

(45) FIG. 7 show the inner and outer control sleeves 13, 14 around the fluid feeder tube 8 according to the invention. A first annular fluid volume 27, a second annular fluid volume 28 and a third annular fluid volume 29 can be defined when the inner and outer control sleeves 13, 14 and the drive shaft cylinder 10b are arranged around the fluid feeder tube 8. The annular fluid volumes 27, 28, 29 are formed between the annular seals 60, 61, 62, 63 of the outer control sleeve 14. The inner control sleeve 13 and the outer control sleeve 14 controls the annular fluid volumes 27, 28, 29, which are circular fluid volumes around the fluid feeder tube 8 which feed fluid independently of drive shaft angle. The radial fluid openings of the fluid feeder tube 8, the inner and outer control sleeves 13, 14 are defined within these three annular fluid volumes 27, 28, 29. By rotating the inner and outer control sleeves 13, 14 it is decided if a high pressure fluid inlet or outlet line, or a low pressure fluid inlet or outlet line within the fluid feeder tube 8 should be in contact with a certain annular fluid volume 27, 28, 29.

(46) FIG. 8 shows a cross section of a gerotor 3 according to the invention, wherein the non-symmetrical drive shaft cylinder 10b is arranged around the outer control sleeve 14. The inner rotor 4 comprises radial fluid feeder channels 9 between every external lobe 4a.

(47) The low and high pressure sections follow the rotation of the drive shaft cylinder 10b. When the drive shaft cylinder 10b rotates in clockwise, a high pressure section 7a extends in the expanding and contracting volume pressure chambers 7 from the same radial position as the first vane 50a is located and in the clockwise direction, to the same radial position as the third vane 50c. A low pressure section 7b extends in the expanding and contracting volume pressure chambers 7 from the same radial position as the third vane 50c is located and in the clockwise direction, to the same radial position as the first vane 50a. If the drive shaft cylinder would be rotated counterclockwise the low pressure section 7b and the high pressure section 7a would change position. The drive shaft cylinder 10b slides on the vanes 50a, 50b, 50c, which seals between the fluid feeder tube 8 and the inner rotor 4.

(48) Three vane volumes 51a, 51b, 51c between the three vanes 50a, 50b, 50c of the drive shaft cylinder 10b, the annular seals 44a, 44b and the inner rotor 4 are filled with fluid. These three vane volumes 51a, 51b, 51c define a sealed volume. These vane volumes 51a, 51b, 51c are filled out by fluid which is sealed and pushed during rotating of the drive shaft cylinder 10b in the direction of the rotating drive shaft cylinder 10b. These vane volumes 51a, 51b, 51c are substantially proportional with the size of the radial fluid openings of the fluid feeder tube 8, the inner and outer control sleeves 13, 14 defined within the three annular fluid volumes 27, 28, 29.

(49) FIG. 9a show a first position of the inner and outer control sleeves 13, 14 around the fluid feeder tube 8, wherein the fluid inlet line 8a is closed. Whereby, no fluid is fed from the fluid inlet line 8a. All annular fluid volumes 27, 28, 29 are connected to low pressure fluid outlet lines 8b, 8d resulting in full recirculation. Fluid which is pumped out through the second annular fluid volume 28 and the third annular fluid volume 29 is sucked into the first annular fluid volume 27. Whereby, no fluid leaves the pump or motor.

(50) FIG. 9b show a second position of the inner and outer control sleeves 13, 14 around the fluid feeder tube 8, wherein a first fluid inlet opening 30 is open to the fluid inlet line 8a. Whereby, fluid is fed from the fluid inlet line 8a to the volume pressure chambers 7. When the first fluid inlet opening 30 is open around a third of the rotational displacement is obtained.

(51) FIG. 9c show a third position of the inner and outer control sleeves 13, 14 around the fluid feeder tube 8, wherein a second fluid inlet opening 31 is open to the fluid inlet line 8a. Whereby, fluid is fed from the fluid inlet line 8a to the volume pressure chambers 7. When the second fluid inlet opening 31 is open around two third of the displacement is obtained.

(52) FIG. 9d show a fourth position of the inner and outer control sleeves 13, 14 around the fluid feeder tube 8, wherein the first fluid inlet opening 30 and the second fluid inlet opening 31 are open to said fluid inlet line 8a. Whereby, fluid is fed from the fluid inlet line 8a to the volume pressure chambers 7. When both the first fluid inlet opening 30 and second fluid inlet opening 31 are open the maximum displacement is obtained.

(53) In the shown example, the normal working range of the hydraulic device is in the range of 0-5000 rpm, preferably in the range of 0-3000 rpm. In the shown example, the normal working pressure of the hydraulic device is in the range of 0-400 bar. However, the invention is not limited to the example described above, but may be modified without departing from the scope of the claims below.

(54) The hydraulic device 1 is filled and fed with fluid and normally the fluid is oil. However, the hydraulic device 1 can also regulate the flow of gases, liquids, fluidized solids, or slurries.

(55) The hydraulic device 1 may be used in various types of applications, such as gerotors and their transmission. One example of the inventive hydraulic device resides in the hydraulic drive of vehicle wheels.

(56) The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting of the invention. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms comprises comprising, includes and/or including when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

(57) Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

(58) The invention should be regarded as illustrative rather than restrictive, and not as being limited to the particular examples discussed above. Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand. As will be realized, the invention is capable of modification in various obvious respects, all without departing from the scope of the appended claims. Accordingly, the drawings and the description thereto are to be regarded as illustrative in nature, and not restrictive.