Hydraulic device

Abstract

The hydraulic device (1) comprises a housing (2) and a shaft (3) mounted in the housing (2) and rotatable about a first axis of rotation (5). The shaft (3) has a flange (8) extending perpendicular to the first axis of rotation (5). The hydraulic device (1) further comprises a plurality of pistons (9) comprising respective spherical piston heads (14), the spherical piston heads (14) having respective center points. The plurality of pistons (9) are fixed to the flange (8) at equal angular distances about the first axis of rotation (5) and have a centerline parallel to the first axis of rotation (5). The hydraulic device (1) comprises a plurality of separate sleeves (10) within which the respective pistons (9) are movable. The hydraulic device (1) comprises a sleeve plate (15) supporting the plurality of sleeves (10). Comprising the plurality of sleeves (10) is rotatable about a second axis of rotation (27) that intersects the first axis of rotation (5) at an acute angle such that each piston (9) of the plurality of pistons (9) moves relative to the mating sleeve (10) between a bottom dead center and a top dead center when the axis of rotation (3) and the cylinder plate (15) comprising the plurality of sleeves (10). The plurality of sleeves (10) are adapted such that at least when one piston (9) of the plurality of pistons (9) is at bottom dead center under operating conditions, centrifugal force acting on the mating sleeve (10) acts in a radial direction from the second axis of rotation (27) between the cylinder plate (15) and a center point of the piston head (14), thereby creating a tilting torque about the center point of the piston head (14). The barrel plate (15) is provided with a plurality of actuators (21) for exerting a reaction force (Fa) on each sleeve (10) in one direction and one position such that at least when one piston (9) of the plurality of pistons (9) is at bottom dead center in an operating condition, the actuator (21) exerts a reaction force (Fa) on each sleeve (10). A reaction force acting on the mating sleeve (10) acts along a line at a distance from the center point of the piston head (14) and generates a reaction torque about the center point of the piston head (14) against the tilt torque, in which the plurality of actuators (21) are controlled such that the reaction force (Fa) increases as the rotational speed of the cylinder plate (15) about the second rotational axis (27) increases.

Description

[0001] The present invention relates to a hydraulic device, which comprises: a housing; a shaft installed in the housing and rotatable around a first rotation axis, wherein the shaft has a flange extending perpendicular to the first rotation axis; a plurality of pistons including respective spherical piston heads, the spherical piston heads having respective center points, the pistons being fixed to the flange at equiangular distances around the first rotation axis and having center lines parallel to the first rotation axis; a plurality of separate sleeves in which each piston can move and a cylinder plate supporting the plurality of sleeves, wherein the cylinder plate including the plurality of sleeves can rotate around a second rotation axis intersecting the first rotation axis at an acute angle, so that when the shaft and the cylinder plate including the plurality of sleeves are rotated, each of the plurality of pistons moves between a lower dead center and an upper dead center relative to a matching sleeve, wherein the plurality of sleeves are adapted so that at least when one of the plurality of pistons is at the lower dead center under operating conditions, the centrifugal force acting on the matching sleeve acts in a radial direction from the second rotation axis between the cylinder plate and the center point of the piston head, thereby generating a tilting torque around the center point of the piston head.

[0002] Such a hydraulic device is known from WO 2006 / 083163. The known hydraulic device has two barrel plates with a first side supported by each panel. The sleeve rests on a second side of the barrel plate opposite the first side. The sleeves are movable on the barrel plate because they follow a non-circular path around the second axis of rotation under operating conditions, while the piston follows a circular path around the first axis of rotation. The path followed by the sleeve on the barrel plate also depends on the transmission between the shaft and the barrel plate, a phenomenon described in EP 1 508 694. In order to minimize friction, there is a layer of hydraulic oil between each of the sleeves and the corresponding barrel plate. In other words, the sleeve floats on the barrel plate. Each of the piston heads is mounted in a matching sleeve, forming a sealing line between the piston head and the sleeve, thereby creating a compression chamber. When the piston is at the bottom dead center, the center of gravity of the sleeve is located between the barrel plate and the center point of the piston head, which means that the centrifugal force on the sleeve generates a tilting torque. Due to the tilting torque, the sleeve tends to tilt around the center point of the piston head because this center point actually forms a pivot point. The tilting torque level varies during the movement of the piston in the sleeve, because it depends on the actual position of the centre of gravity of the sleeve, including the hydraulic fluid in the sleeve, although the influence of the hydraulic fluid is relatively small. Under operating conditions, when the piston moves from bottom dead centre to top dead centre, the distance between this centre of gravity and the centre point of the piston head will first decrease. At a certain angular position of the barrel plate about the second axis of rotation, the centre point of the piston head and the centre of gravity of the sleeve including the hydraulic fluid in the compression chamber may coincide; at top dead centre, this centre of gravity may even be located outside the centre point of the piston head, as seen from the barrel plate.

[0003] In this known hydraulic device, the fact that the sleeve is pressed against the barrel plate by the pressure in the compression chamber partially prevents the tilting of the sleeve, since the diameter of the through hole in the sleeve bottom of each sleeve is smaller than the diameter of the sleeve jacket extending from the sleeve bottom. The pressing force depends on this pressure and varies with the rotation of the shaft. When the oil pressure is relatively low, for example when the oil is sucked into the compression chamber during a part of the shaft rotation, the pressing force is very low, which may cause the sleeve to tilt due to centrifugal force. This may cause a gap to appear between the sleeve and the barrel plate, so that the oil can leak through the gap. Any leakage will reduce the efficiency of the hydraulic device, which is a disadvantage. Therefore, the known hydraulic device is also provided with a fixing element, which presses each sleeve against the barrel plate by a separately acting spring device. The disadvantage of this known hydraulic device is that at high rotation speeds, the spring force is not sufficient to avoid the sleeve tilting. The hydraulic device described in EP 1 855 002 has the same disadvantage.

[0004] When the shaft rotates at high speed, the tilting torque on each sleeve will also generate a tilting torque on each mating barrel plate. This may cause leakage between each pair of barrel plates and the face plate.

[0005] An object of the present invention is to provide an improved hydraulic device.

[0006] This object is achieved by a hydraulic device according to the present invention, which is characterized in that a cylinder plate is provided with a plurality of actuators, which are used to apply a reaction force to each sleeve in one direction and at one position, so that when at least one of the plurality of pistons is at the bottom dead center under operating conditions, the reaction force acting on the mating sleeve acts along a line at a certain distance from the center point of the piston head, and generates a reaction torque around the center point of the piston head to resist the tilting torque, wherein the plurality of actuators are controlled so that the reaction force increases with the increase of the rotation speed of the cylinder plate around the second rotation axis.

[0007] An advantage of the presence of an actuator is that the reaction force is actively applied. This means that the reaction force does not depend on the tilting movement of the sleeve, such as in the case of a passive spring arrangement.

[0008] The actuator may be adapted so that when the shaft is running at a fixed speed, the reaction force acting on each sleeve is substantially the same. This means that the reaction force applied by the actuator is independent of the rotational position of the shaft.

[0009] The reaction force may act in a radial direction of the second rotation axis.

[0010] The reaction force may be directed toward the second axis of rotation.

[0011] When at least one of the plurality of pistons is at bottom dead center, a reaction force may be applied to the corresponding sleeve at a position between the barrel plate and the center of the piston head.

[0012] Preferably, the reaction force is applied to the sleeve at a distance from the cartridge plate, where the center of gravity of each sleeve is located at or close to this position, because the centrifugal forces can be balanced so that the tilting torque is minimized, regardless of the rotational position of the cartridge plate. The position of the centrifugal force on the sleeve including the hydraulic fluid in the sleeve depends on the rotational position of the cartridge plate, but the weight of the sleeve is greater than the weight of the hydraulic fluid in the sleeve, which more or less determines the center of gravity.

[0013] The reaction force can act on the outside of the sleeve in a direction away from the second axis of rotation. In this case, the reaction force points to the second axis of rotation.

[0014] Each actuator may include a counterweight coupled to the cartridge plate and movable relative to the cartridge plate in a radial direction of the second axis of rotation, and cooperating with a corresponding sleeve via a transmission device to exert a reaction force on the corresponding sleeve, wherein the transmission device and the counterweight are adapted such that under operating conditions, the centrifugal force on the counterweight causes the transmission device to exert a reaction force on the corresponding sleeve. In this case, the counterweight rotates with the cartridge plate, which means that the centrifugal force on the counterweight automatically increases the reaction force as the rotation speed of the cartridge plate around the second axis of rotation increases.

[0015] In a particular embodiment, the transmission device comprises a lever mounted to the barrel plate by a pivot having a pivot axis, wherein the lever comprises a first arm and a second arm extending in a direction different from the pivot axis, wherein the first arm cooperates with a corresponding sleeve for exerting a reaction force on the corresponding sleeve, and the second arm comprises a counterweight, wherein the lever is adapted so that under operating conditions, the first arm exerts a reaction force on the corresponding sleeve due to the centrifugal force generated by the counterweight on the second arm. This is a relatively simple mechanical structure for generating a reaction force on the sleeve.

[0016] The pivot axis may extend parallel to the second rotation axis.

[0017] The pivot may include a ridge at one of the lever and the barrel plate, the ridge being supported by the other of the lever and the barrel plate, thereby forming a fulcrum.

[0018] In a practical embodiment, ridges are provided at the levers, the cartridge plate comprising an annular cartridge plate wall supporting the ridges of the respective levers.

[0019] Each of the levers may be provided with a protrusion on a corresponding ridge which is located in a matching hole in the barrel plate wall, or each of the levers may be provided with a hole on a corresponding ridge which receives a matching protrusion on the barrel plate wall, wherein the hole and the protrusion allow the lever to pivot relative to the barrel plate about the pivot axis. This configuration facilitates assembly of the lever and the barrel plate and locks the lever relative to the barrel plate in the circumferential direction of the barrel plate.

[0020] The second arm of each lever can be located partly between two adjacent sleeves. This makes the hydraulic device compact.

[0021] In an alternative embodiment, the pivot axis extends tangentially to the cartridge plate.

[0022] The invention will be explained hereinafter with reference to the accompanying highly schematic drawings, which show embodiments of the invention by way of example.

[0023] Figure 1 is a cross-sectional view of an embodiment of a hydraulic device according to the present invention.

[0024] Figure 2 yes Figure 1 An enlarged top view of a portion of the hydraulic device shown in FIG.

[0025] Figure 3 yes Figure 2 A cut-away side view of the portion is shown in FIG.

[0026] Figure 4 yes Figure 2 An enlarged top view of a portion of the structure illustrates the stresses under operating conditions.

[0027] Figure 5 is an enlarged perspective view of a lever from different sides. Figure 2-4 It can be seen in.

[0028] Figure 6 is a cross-sectional view of a portion of an alternative embodiment of the hydraulic device.

[0029] Figure 1 The internal components of the hydraulic device 1, such as a pump, a hydraulic motor or a hydraulic transformer, are shown, which are mounted in a known manner in a housing 2. The hydraulic device 1 is provided with a shaft 3, which is supported by bearings 4 on both sides of the housing 2, and the shaft 3 is rotatable about a first rotation axis 5. The housing 2 is provided with an opening with a shaft seal 6 on one side in a known manner, so that one end of the shaft 3 protrudes from the housing 2. If the hydraulic device 1 is a pump, a motor can be coupled to this end of the shaft 3, and if the hydraulic device 1 is a motor, a driven tool can be coupled thereto.

[0030] The hydraulic device 1 comprises a plurality of panels 7 mounted at a distance from each other inside the housing 2. In the embodiment shown, the plurality of panels 7 have a fixed position relative to the housing 2 in the direction of rotation of the housing 2, but in an alternative embodiment they may be rotatable relative to the housing 2. The shaft 3 extends through a central through hole in the panel 7.

[0031] The shaft 3 is provided with a flange 8, which extends perpendicularly to the first axis of rotation 5. A plurality of pistons 9 are fixed to both sides of the flange 8 at equal angular distances around the first axis of rotation 5, in this case fourteen pistons 9 on each side. Each of the pistons 9 has a modular structure, but in an alternative embodiment this may be different. The pistons 9 have a centerline extending parallel to the first axis of rotation 5. In the example Figure 1 In the embodiment shown, the planes of the panels 7 are angled relative to each other and relative to the plane of the flange 8 .

[0032] Each of the pistons 9 cooperates with a separate sleeve 10 to form a compression chamber 11 of variable volume. Figure 1 The hydraulic device 1 shown in has 28 compression chambers 11. Each of the sleeves 10 includes a sleeve bottom 12 and a cylindrical sleeve jacket 13. The sleeve jacket 13 extends from the sleeve bottom 12. Each piston 9 is directly sealed to the inner wall of the sleeve jacket 13 by a piston head 14, which has a spherical outer side including a center point.

[0033] The sleeve bottom 12 of each sleeve 10 is supported by a respective sleeve plate 15, which is assembled around the shaft 3 by means of respective ball hinges 16 and is coupled to the shaft 3 by means of keys 17. Therefore, under operating conditions, the sleeve plate 15 rotates together with the shaft 3. The side of each sleeve plate 15 facing away from the flange 8 is supported by respective supporting surfaces of the panel 7. Due to the inclined orientation of the panel 7 relative to the flange 8, the sleeve plate 15 pivots about the ball hinge 16 during rotation together with the shaft 3. The sleeve plate 15 rotates about respective second rotation axes 27, which are at an acute angle relative to the first rotation axis 5. This means that the sleeve 10 also rotates about respective second rotation axes 27. As a result, when the shaft 3 is rotated, the volume of the compression chamber 11 changes.

[0034] During the rotation of the barrel plate 15, each sleeve 10 performs a combined translational and rotational movement around the mating piston 9. Therefore, the outer side of each piston head 14 is spherical. The spherical shape forms a sealing line between the piston head 14 and the sleeve jacket 13, which extends perpendicular to the center line of the mating sleeve 10. The diameter of each piston 9 near the flange 8 is smaller than the diameter at the piston head 14, so as to allow the mating sleeve 10 to perform relative movement around the piston 9. Under operating conditions, each of the pistons 9 moves between the bottom dead center and the top dead center in the corresponding sleeve 10. Figure 1In the embodiment, the upper piston 9 at the left cylinder plate 15 is at the top dead center, and the lower piston 9 at the left cylinder plate 15 is at the bottom dead center.

[0035] The angle between the first and respective second rotational axes 27 is in practice approximately 9 degrees, but may be smaller or larger.

[0036] Under operating conditions, there is a slight layer of hydraulic fluid between the sleeve bottom 12 and the respective cartridge plate 15, which causes the sleeve 10 to float on the respective cartridge plate 15. This minimizes the friction between the sleeve bottom 12 and the cartridge plate 15, since the sleeve 10 moves slightly on the cartridge plate 15 in a direction perpendicular to the second axis of rotation 27, such movement being explained, for example, in EP 1 508 694.

[0037] The sleeve 10 is locked to the cartridge plate 15 by means of the fixing element 19 in a direction parallel to the respective second axis of rotation 27, so as to hold the sleeve 10 against the cartridge plate 15 when the hydraulic pressure must still be increased when the hydraulic device 1 is activated. The force of the fixing element 19 on the sleeve 10 is limited.

[0038] The barrel plate 15 is pressed against each panel 7 by a spring 18 mounted in a hole in the shaft 3, which presses each side wall against the panel 7. The compression chamber 11 communicates with a matching channel 20 in the barrel plate 15 via a central through hole in each sleeve bottom 12. The channel 20 in the barrel plate 15 communicates with the high-pressure port and the low-pressure port in the housing 2 via a channel in the panel 7.

[0039] Figure 2-4 One of the plurality of cartridge plates 15 and the corresponding sleeve 10 is shown in more detail. The cartridge plate 15 is provided with an actuator in the form of a plurality of levers 21 which are located beside each sleeve 10 and which cooperate with each sleeve collet 13. Figure 5 One of the plurality of levers 21 is shown as seen from a different side. Each lever 21 is provided with a ridge 22 supported by the inner side of an annular barrel wall 23. The barrel wall 23 is fixed to or is part of the barrel plate 15. The contact point where the barrel wall 23 supports each ridge 22 forms a fulcrum. Each fulcrum and the ridge 22 form a pivot of the corresponding lever 21, including a pivot axis PA extending parallel to the second rotation axis 27, see Figure 4 and Figure 5 .

[0040] Each of the plurality of levers 21 is mounted to the barrel plate wall 23 by a pin 24 which extends from the ridge 22 and passes through a matching through hole in the barrel plate wall 23. This holds the lever 21 in position in the circumferential direction of the barrel plate wall 23. There is sufficient clearance between the pin 24 and the through hole in the barrel plate wall 23 to allow the lever 21 to tilt about the respective pivot axis PA. Figure 3The width of the second arm 21b of each lever 21 measured in the axial direction of the second rotation axis 27 is shown to increase in the direction from the pivot axis PA to its free end. The free end is locked between the cartridge plate 15 and the fixing element 19 in the axial direction of the second rotation axis 21 .

[0041] In an alternative embodiment (not shown), the pin 24 may be fixed to the barrel plate wall 23 , with a mating hole being located in each lever 21 .

[0042] Figure 5 It is shown that each of the plurality of levers 21 comprises a first arm 21a and a second arm 21b extending in different directions from the pivot axis PA. The first arm 21a cooperates with the corresponding sleeve collet 13. The first arm 21a has a semi-cylindrical pusher 25 which contacts the side of the sleeve collet 13 facing away from the second rotation axis 27. The second arm 21b is larger and heavier than the first arm 21a and forms a counterweight. Figure 4 The centre of gravity COG of the second arm 21b and the centrifugal force Fb generated on the lever 21 are shown in the operating condition. The lever 21 thus causes the first arm 21a to exert a reaction force Fa on the sleeve jacket 13 directed towards the second axis of rotation 27 . Figure 4 It is shown that the centrifugal force Fb acts on the second arm 21b at a distance L1 from the pivot axis PA, and the pusher 25 contacts the sleeve jacket 13 at a distance L2 from the pivot axis PA, and the distance L1 is greater than the distance L2. This means that the reaction force Fa is greater than the centrifugal force Fb. The reaction force Fa acts on the sleeve jacket 13 at a position approximately half of the axial length of the sleeve jacket 13, see Figure 3 This is a position at a certain distance from the barrel plate 15, where the center of gravity of the sleeve 9 is located or close to it. Therefore, the centrifugal force acting on the sleeve 10 due to the inertia of the sleeve 10 can be balanced by the reaction force Fa. This is related to minimizing the tilting torque on the sleeve 10 about the center point of the piston head 14, which may cause the sleeve 10 to tilt and thus cause leakage between the sleeve bottom 12 and the barrel plate 15. The reaction force Fa increases with the increase of the rotation speed of the barrel plate 15 about the second rotation axis 27.

[0043] Figure 4The second arm 21b of each of the levers 21 is shown partially located between two adjacent sleeves 10. This space is available due to the cylindrical shape of the sleeve collet 13. Each of the second arms 21b is shaped so that it does not contact the adjacent sleeves 10, i.e. the sleeve 10 that mates with it and the next sleeve 10, and does not contact the barrel plate wall 23 under operating conditions. Since the sleeves 10 move on the barrel plate 15, causing the levers 21 to rotate slightly, there must be some clearance between each of the sleeve collets 13 and the adjacent second arms 21b and between the second arms 21a and the barrel plate wall 23. For the same reason, the first arms 21a are shaped so that they do not contact the barrel plate wall 23 under operating conditions.

[0044] Figure 6 A portion of a cartridge plate 15 of an alternative embodiment of the hydraulic device 1 is shown. The figure shows the centrifugal force Fs of the sleeve 10, which is directed away from the second axis of rotation 27. In this embodiment, the cartridge plate 15 is also provided with a plurality of actuators in the form of levers 21, but the levers 21 have pivots 26, which include a pivot axis extending tangentially to the cartridge plate 15, i.e. the pivot axis extending perpendicularly to the second axis of rotation 27 and at a distance from the second axis of rotation 27. Similar to the embodiment described above, in operating conditions, the lever 21 causes the first arm 21a to exert a reaction force Fa on the sleeve collet 13, which reaction force Fa is directed towards the second axis of rotation 27 due to the centrifugal force Fb on the second arm 21b directed away from the second axis of rotation 27.

[0045] The invention is not limited to the embodiments shown in the drawings and described above, which can be varied in different ways within the scope of the claims and their technical equivalents. For example, the reaction force can also be applied to the sleeve at different positions of the sleeve, as long as the direction and position of the reaction force applied to each sleeve are such that at least when one of the multiple pistons is at the bottom dead center under operating conditions, the reaction force acting on the matching sleeve acts along a line at a certain distance from the center point of the piston head and causes a reaction torque around the center point of the piston head to resist the tilting torque.

Claims

1. A hydraulic device (1), comprising a housing (2); a shaft (3) mounted in the housing (2) and rotatable about a first rotation axis (5), wherein the shaft (3) has a flange (8) extending perpendicular to the first rotation axis (5); a plurality of pistons (9) each having a spherical piston head (14), the spherical piston head (14) having a respective center point, the plurality of pistons (9) being fixed to the flange (8) at equiangular distances about the first rotation axis (5) and having a center line parallel to the first rotation axis (5); a plurality of separate sleeves (10) in which each piston (9) is movable and a sleeve plate (15) supporting the plurality of sleeves (10), wherein the sleeve plate (15) including the plurality of sleeves (10) 15) can rotate about a second rotation axis (27) intersecting the first rotation axis (5) at an acute angle, so that when the shaft (3) and the cylinder plate (15) including the plurality of sleeves (10) are rotated, each piston (9) of the plurality of pistons (9) moves between the lower dead center and the upper dead center relative to the matching sleeve (10), wherein the plurality of sleeves (10) are adapted so that at least when one piston (9) of the plurality of pistons (9) is at the lower dead center under operating conditions, the centrifugal force acting on the matching sleeve (10) acts in a radial direction from the second rotation axis (27) between the cylinder plate (15) and the center point of the piston head (14), thereby generating a tilting torque about the center point of the piston head (14), characterized in that The cylinder plate (15) is provided with a plurality of actuators (21), which are used to apply a reaction force (Fa) to each sleeve (10) in one direction and at one position, so that at least when one of the plurality of pistons (9) is at the bottom dead center under operating conditions, the reaction force acting on the mating sleeve (10) acts along a line at a certain distance from the center point of the piston head (14), and generates a reaction torque around the center point of the piston head (14) to resist the tilting torque, wherein the plurality of actuators (21) are controlled so that the reaction force (Fa) increases with the increase of the rotation speed of the cylinder plate (15) around the second rotation axis (27).

2. The hydraulic device (1) according to claim 1, wherein the plurality of actuators (21) are adapted so that when the shaft (3) runs at a fixed speed, the reaction forces (Fa) acting on the respective sleeves (10) are substantially the same.

3. The hydraulic device (1) according to claim 1 or 2, wherein the reaction force (Fa) acts in a radial direction of the second rotation axis (27).

4. The hydraulic device (1) according to claim 3, wherein the reaction force (Fa) is directed towards the second rotation axis (27).

5. A hydraulic device (4) according to claim 1, wherein at least when one of the multiple pistons (9) is at the bottom dead center, the reaction force (Fa) is applied to the corresponding sleeve (10) at a position between the cylinder plate (15) and the center of the piston head (14).

6. A hydraulic device (1) according to claim 4 or 5, wherein the reaction force (Fa) is applied to the sleeve (10) at a position at a certain distance from the cylinder plate (15), and the center of gravity of each sleeve (10) is located at or close to the position.

7. A hydraulic device (1) according to any one of the preceding claims, wherein the reaction force (Fa) acts on the outer side of the sleeve (10) in a direction away from the second rotation axis (27).

8. A hydraulic device (1) according to any one of the preceding claims, wherein each of the actuators (21) includes a counterweight, which is coupled to the barrel plate (15) and can be moved relative to the barrel plate (15) in the radial direction of the second rotation axis (27), and cooperates with the corresponding sleeve (10) through a transmission device (21) to apply the reaction force (Fa) on the corresponding sleeve (10), wherein the transmission device and the counterweight are adapted so that under operating conditions, the centrifugal force on the counterweight causes the transmission device to apply the reaction force (Fa) on the corresponding sleeve (10).

9. A hydraulic device (1) according to claim 8, wherein the transmission device includes a lever (21) mounted on the cylinder plate (15) via a pivot (22, 26) having a pivot axis (PA), wherein the lever (21) includes a first arm (21a) and a second arm (21b) extending in a direction different from the pivot axis (PA), wherein the first arm (21a) cooperates with the corresponding sleeve (10) for applying the reaction force (Fa) on the corresponding sleeve (10), and the second arm (21b) includes the counterweight, wherein the lever (21) is adapted so that under operating conditions, the centrifugal force generated by the counterweight on the second arm (21b) causes the first arm (21a) to apply the reaction force (Fa) on the corresponding sleeve (10).

10. The hydraulic device (1) according to claim 9, wherein the pivot axis (PA) extends parallel to the second rotation axis (27).

11. A hydraulic device (1) according to claim 9 or 10, wherein the pivot comprises a ridge (22) located at one of the lever (21) and the cartridge plate (15), the ridge (22) being supported by the other of the lever (21) and the cartridge plate (15) to form a fulcrum.

12. The hydraulic device (1) according to claim 11, wherein the ridge (22) is provided at the lever (21), the cartridge plate (15) comprising an annular cartridge plate wall (23) supporting the ridge (22) of each lever (21).

13. A hydraulic device (1) according to claim 12, wherein each of the levers (21) is provided with a protrusion (24) on the corresponding ridge (22), and the protrusion (24) is located in a matching hole in the barrel plate wall (23), or each of the levers is provided with a hole on the corresponding ridge, which accommodates the matching protrusion on the barrel plate wall, wherein the hole and the protrusion (24) allow the lever (21) to pivot relative to the barrel plate (15) about the pivot axis (PA).

14. A hydraulic device (1) according to any one of the preceding claims 9 to 13, wherein the second arm (21b) of each lever (21) is partially located between two adjacent sleeves (10).

15. The hydraulic device (1) according to claim 9, wherein the pivot axis (PA) extends tangentially to the cartridge plate (15).

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