KR20000022332A - Axial piston machine with damping element for the inclined or wobble plate - Google Patents

Abstract

PURPOSE: A method to train an axial piston machine in such a way that the course of motion takes place not suddenly, but continuously when the diagonal or swash plate is swiveling is provided. CONSTITUTION: The axial piston machine(1) which comprises a cylinder block(2) having cylinder bores(3,4) in which pistons(5,6) are movably guided. The axial piston machine(1) comprises a pivot device(31) for varying the inclination of the inclined or wobble plate(25) by pivoting about a pivot axis(27). The machine(1) has a damping element(41) which comprises a damping piston(40) which acts on the inclined or wobble plate(25) and is movably disposed in a damping cylinder(42) which is connected to a pressure fluid reservoir(48) through a throttle element(47) and a non-return valve(44) which enables pressure fluid to flow in an unthrottled manner from the pressure fluid reservoir(48) into the damping cylinder(42) and prevents the pressure fluid from flowing out of the damping cylinder(42) by bypassing the throttle element(47).

Description

Axial piston device with damping member for inclined plate or wobble plate

Axial piston devices of this kind are known, for example, from DE 34 28 591 A1. In this axial piston device, a plurality of piston cavities are formed in a rotating cylinder block in a known manner, in which the piston is guided to be movable. The piston is supported on the non-rotating inclined plate by slippers. The inclination of the inclined plate, which determines the moving volume of the axial piston device, is adjustable by the hydraulic regulating piston, where the inclined plate can pivot within a predetermined angle range about the pivot axis. When the inclined plate pivots back from the raised position to the zero raised position, the adjustment pressure acting on the hydraulic regulating piston increases so that the inclined plate pivots back until it reaches the zero raised position in contact with the contact surface. However, since the movement of the inclined plate cannot be properly controlled, the inclined plate hits the contact surface violently when reaching the zero rising position. This is undesirable because it increases the wear of the contact surface and the inclined plate and also causes the entire axial piston device to be subjected to mechanical impact loads.

DE 44 40 452 A1 discloses an axial piston device with two independent hydraulic cylinders for changing the inclination of the inclined plate. Here, one of the hydraulic cylinders is used to pivot the inclined plate outward and the other hydraulic cylinder is used to invert the inclined plate. In this method the inclined plate is guided in a controlled manner during the overall movement, but the manufacturing cost is high because the second hydraulic cylinder becomes a fairly large structure. In addition, it is necessary to hydraulically control both hydraulic cylinders independently.

The present invention relates to an axial piston device according to the preamble of claim 1.

1 is an axial partial sectional view of a first embodiment of an axial piston device according to the invention in a first pivotal position of an inclined plate,

FIG. 2 is an axial partial sectional view of a first embodiment of the axial piston device of FIG. 1 according to the invention in a second pivotal position of an inclined plate, FIG.

3 is a view schematically showing a method of operating the damping member;

4A is a diagram showing the distribution of forces in the embodiment shown in FIG. 1 as an axial piston device according to the present invention;

4B is a side view of FIG. 4A,

4C is a top view of FIG. 4A

5 is an axial partial sectional view of a second embodiment of an axial piston device according to the invention in a first pivotal position of an inclined plate,

6 is an axial partial cross-sectional view of a second embodiment of the axial piston device of FIG. 5 according to the invention in a second pivotal position of an inclined plate;

Explanation of symbols on the main parts of the drawings

1: axial piston device 2: cylinder block

3, 4: cylinder cavity 5, 6: piston

7, 8: connection duct 9, 10: control opening

11: control disc 12: cylinder block axis

13, 14: head 15, 16: spherical bearing

17, 18: slippers 19, 20: piston recess

21, 22: connection duct 23, 24: connection duct

25 inclined plate 26 sliding surface

27: pivot axis 28, 29: first and second contact surface

30: stationary station member 31: turning device

40: damping piston 41: damping member

42: damping cylinder 43: restoring spring

44: check valve 45: supply duct

46: inside the housing 47: throttle member

48: pressure fluid reservoir

It is an object of the present invention to improve an axial piston device with an inclined or wobble plate structure which allows the movement to continue without sharpening during the swiveling of the inclined plate or wobble plate.

This object is achieved by the features of the appended claims.

The present invention is based on the principle that the pivotal recovery of the warp plate or wobble plate can be controlled by providing a damping member acting on the warp plate or wobble plate. The damping piston is movably mounted in the damping cylinder, which is connected to the pressure fluid reservoir via a throttle member and a check valve parallel to the throttle member. Here, the check valve unthrottles the pressure fluid from the pressure fluid reservoir to the damping cylinder and prevents the outflow of the non-throttled pressure fluid from the damping cylinder to bypass the throttle member.

Claims 2 to 12 include other features of the present invention.

According to claim 2 or 3, as soon as the damping piston moves freely in the direction of increasing the volume of the damping cylinder, the damping piston retracts the pressure fluid from the pressure fluid reservoir via a check valve and optionally through a throttle valve. This acts on the damping piston. Here, since the damping cylinder is filled with pressure fluid in an instant, the pivoting motion of the inclined plate or wobble plate occurs directly. According to claim 4, the pressure medium reservoir may be a leaking fluid collection chamber surrounding the damping member, which is generally formed by the housing interior of the axial piston device.

According to claim 5, the inclined plate or wobble plate can have a first pivot position of a large tilt angle and a second pivot position of a small tilt angle and can pivot between these two pivot positions. According to claim 6, the axial piston device can be designed to have an inclined plate structure, and the damping member can be installed in the inclined plate according to claim 7 or in a stationary stationary member opposite the inclined plate according to claim 9. . Here, the restoring spring keeps the damping piston in contact with the inclined plate according to claim 10 or in contact with the stationary reverse member according to claim 8.

According to claim 11, the inclined plate may comprise first and second contact surfaces on opposite sides of the piston, each of which contact forms a contact for the first and second pivot positions of the inclined plate.

According to claim 12, the combined force of the force exerted on the inclined plate by the damping piston, the force exerted on the inclined plate by the pivoting device during swing, and the force applied to the inclined plate by the piston are located on the cylinder block axis. It is particularly preferred that the point of application at which the damping piston acts on the inclined plate is biased relative to the cylinder block axis in such a way that it acts at the center of force. This prevents asymmetry of bearing force and avoids bearing-out of the bearing.

The present invention will be described in detail with reference to the preferred embodiments with reference to the accompanying drawings.

1 and 2 are axial longitudinal cross-sectional views that partially show an axial piston device 1 improved according to the invention. The axial piston device 1 shown by way of example in FIGS. 1 and 2 is designed in an inclined plate structure and includes a cylinder block 2, which has a plurality of cylinder cavities 3, 4. ) And they are arranged in a circle. The pistons 5 and 6 are provided in the cylinder cavities 3 and 4 so as to be movable. The cylinder cavities 3, 4 are connected to the elongated control openings 9, 10 of the fixed control disk 11 via connecting ducts 7, 8. Since the cylinder block 2 rotates about the cylinder block axis 12, the cylinder cavities 3 and 4 are connected to the low pressure line (not shown) and the control opening 10 which are connected to the control opening 9. It is cyclically connected to the connected high voltage line (not shown). Piston 5 at the opposite end of control disk 11 to form spherical heads 13, 14 mounted in spherical bearings 15, 16 of slippers 17, 18 which engage pistons 5, 6. , 6) is molded. The pistons 5, 6 are made of hollow pistons and include piston recesses 19, 20, respectively. For hydrostatic relief, the piston recesses 19, 20 are connected via connecting ducts 21, 22 of the pistons 5, 6 and through the connecting ducts 23, 24 of the slippers 17, 18. Connected to the push-button provided on the slippers 17 and 18.

The pistons 5, 6 are supported on the slide surface 26 of the inclined plate 25 by slippers 17, 18. The inclined plate 25 is mounted to pivot about the pivot axis 27 and includes a first contact surface 28 and a second contact surface 29 on opposite sides of the pistons 5, 6. As shown in FIG. 1, when the first contact surface 28 of the inclined plate 25 contacts the stationary reverse member 30, the first inclined angle of the inclined plate 25 or the sliding surface 26 is relatively large. Inclined with respect to the cylinder block axis 12. On the other hand, when the second contact surface 29 of the inclined plate 25 is in contact with the fixed inverse member 30, as shown in FIG. 2, the inclined plate 25 or the sliding surface 26 is the first It is inclined with respect to the cylinder block axis 12 at a second inclination angle smaller than the inclination angle. Therefore, in the embodiment, the inclination of the inclined plate 25 can be turned back and forth between two independent turning positions by the turning device 31. The turning device 31 may comprise, for example, a hydraulically actuated control piston acting on the inclined plate 25 in a force-locking manner.

According to the invention, the damping piston 40 of the damping member 41 also acts on the inclined plate 25. In the embodiment shown in FIGS. 1 and 2, the damping member 41 is integrated in the inclined plate 25. The damping piston 40 is movably mounted in the damping cylinder 42 provided in the inclined plate 25 of the embodiment of FIGS. 1 and 2. The damping cylinder 42 is composed of a closed cavity that is open on the second contact surface 29 of the inclined plate 25. The damping piston 40 is in contact with the stationary reverse member 30 by a restoring spring 43 installed in the damping cylinder 42. The stationary station member 30 may be an end plate of the housing, for example. The damping cylinder 42 is connected to the housing interior 46 via a check valve 44 and a supply duct 45, which surrounds the inclined plate 25 and the cylinder block 2. It is filled by leaking fluid because it acts as a leaking fluid collection chamber. The damping cylinder 42 is also connected to the housing interior 46 of the axial piston device 1 via a throttle member 47. In the embodiment, the throttle member 47 consists of a cavity having a relatively small cross section. The supply duct 45 and the check valve 44 are arranged in parallel with the throttle member 47.

The damping member 41 according to the present invention operates as follows.

When the inclined plate 25 pivots in the direction of the first pivot position shown in FIG. 1 from the second pivot position shown in FIG. 2 as a result of the reduction of the pivoting device 31, the damping piston 40 is restored. The spring 43 comes into contact with the stationary reverse member 30. During this process, pressure fluid is drawn in through the throttle member 47 out of the housing interior 46 which is sucked through the supply duct 45 and the open check valve 44 and filled with leaking fluid. Since the filling of the damping cylinder 42 takes place quickly through the supply duct 45 and the check valve 44, the damping piston 40 continues to be in contact with the stationary station member 30.

In contrast, when the inclined plate 25 turns from the first turning position shown in FIG. 1 to the second turning position shown in FIG. 2 as a result of the action by the turning device 31, the check valve 44 Closing the supply duct 45 and the pressure fluid in the damping cylinder 42 can only flow out of the damping cylinder 42 through the throttle member 47. In this method, the desired damping is obtained and it is possible to prevent the sudden occurrence of the turning motion of the inclined plate 25 which causes the second contact surface 29 to strike the stationary reverse member 30 suddenly. The sudden movement may cause rapid wear of the inclined plate 25 and the stationary reverse member 30, and the axial piston device 1 may also be subjected to impact loads during the undesirable pivoting movement.

As the damping member 41 according to the present invention is provided, the turning process is slightly suspended so that the continuous turning movement of the inclined plate 25 is not abrupt. In addition, while in the first pivot position shown in FIG. 1 and while turning from the first pivot position shown in FIG. 1 to the second pivot position shown in FIG. 2, the damping member 41 according to the invention It is ensured that the portion of the inclined plate 25 arranged above the pivot axis 27 is supported at a certain angle so that the load on the inclined plate 25 is advantageously reduced as an effect according to the invention.

3 shows a method of operating the damping member 41 according to the invention in a hydraulic balanced circuit diagram. The members already mentioned above have the same reference numerals. As described above, suctioning the pressure fluid from the pressure fluid reservoir 48, which may be, for example, the interior of the housing 46, is such that the supply duct 45 is disposed between the supply duct 45 and the damping cylinder 42. And through the check valve 44. The throttle member 47 is installed in parallel with the check valve 44 and the supply duct 45 so that the check valve 44 is closed from the damping cylinder 42 into the pressure fluid reservoir 48 in the closed state. Can be throttled.

4a to 4c show the distribution of forces in the axial piston device 1 of the invention according to the embodiment of FIGS. 1 and 2. Here, FIG. 4A is a view corresponding to FIG. 1, FIG. 4B is a side view viewed from the side direction of the inclined plate 25 opposite the pistons 5, 6, and FIG. 4C is a plan view of FIG. 4A.

As shown in Figs. 4A to 4C, the adjusted inclined plate 25 has a force F _V applied by the swinging device 31 and a shaft vibration force F _L applied by the bearing of the swing shaft 27. _{/ R} ), (two in this embodiment) by the force F _DR exerted by the damping pistons 40a and 40b, and by the force F _KL exerted in the opposite direction by the pistons 5 and 6 Under action. Here, if each of the damping pistons 40a and 40b acting on the left and right sides is applied to the cylinder block axis 12 with the application point acting on the inclined plate 25 inclined by the corresponding damping pistons 40a and 40b. The force F _DR applied on the plate 25, the force F _V applied to the inclined plate 25 by the turning device 31 during the turning, and the inclined plate by the pistons 5, 6 ( There is a special advantage that the force consisting of the force F _KL applied to 25) acts on the center S of the force located on the cylinder block axis 12. Here, a symmetrical distribution of the axial vibration force acting on the bearing of the cylinder block 2 is obtained and is not affected by inertia. In addition, the lever action of the bearing of the cylinder block 2 is canceled. In addition, the triangular force of FIG. 4B may be drawn for the right damping piston 40a but is omitted here for simplicity.

5 and 6 are axial longitudinal cross-sectional views of a second embodiment of the axial piston device 1 according to the invention. The reference numerals of the members which have been described above are used the same in order not to overlap.

The difference between the embodiment shown in Figs. 5 and 6 and the embodiment shown in Figs. 1 and 2 is that the damping member 41 according to the present invention is not provided in the inclined plate 25 and the inclined plate 25 is provided. It is installed in the stationary stationary member 30, ie, the housing end plate, which is opposed to. The structure of the damping member 41 is basically the same as that of FIG. The damping piston 40 is movably installed in the damping cylinder 42 and the restoring spring 43 is in such a way that the damping piston 40 abuts the inclined plate 25, preferably in contact with the second contact surface 29. Is affected by). The suction of pressure fluid from the housing interior 46 is accomplished by the supply duct 45 and the check valve 44 which is opened in the suction stage. When the inclined plate 25 pivots from the first pivot position shown in FIG. 5 to the second pivot position shown in FIG. 6, the pressure fluid is in this embodiment a throttle member 47 consisting of a cavity having a small diameter. ) And outflow of the damping cylinder 42 through the outlet duct 48 connected thereto, thereby attenuating the support of the inclined plate 25 and the movement of the inclined plate 25 during the turning.

The invention is not limited to the described embodiments. As mentioned above, the present invention may be used in an axial piston device with a wobble plate structure. In addition, the damping device may be installed at any desired position to actuate the damping piston 40 in a manner appropriate to the inclined plate 25 or the wobble plate. Moreover, additional damping members may be provided in the region of the first contact surface 28 for damping the other turning device.

Claims (12)

An axial piston device (1) having a cylinder block (2), wherein cylinder cylinders (3, 4) are formed in the cylinder block (2), and the pistons in the cylinder cavity (3, 4). (5, 6) can be moved, the piston (5, 6) is supported on the inclined plate or wobble plate (25) to perform the lifting movement, the inclined plate (25) is pivoting the pivot shaft (27) In the axial piston device provided with a turning device 31 for changing the inclination of the inclined plate by turning the inclined plate to the center. One or more damping members (41) with damping pistons (40), said damping pistons (40) acting on said inclined plate (25) and being movably mounted in said damping cylinder (42), said The damping cylinder 42 is connected to the pressure fluid reservoir 48 via a throttle member 47 and a check valve 44 parallel to the throttle member 47, the check valve 44 being connected to the pressure fluid reservoir. Non-cross feed the pressure fluid from the 48 into the damping cylinder 42 and prevent the outflow of the non-throttled pressure fluid from the damping cylinder 42 bypassing the throttle member 47. Axial piston device. The pressure fluid reservoir (48) according to claim 1, wherein as soon as the damping piston (40) moves freely in the direction of increasing the volume of the damping cylinder (42), the damping piston (40) passes through the check valve (44). And a restoring spring (43) acting on the damping piston (40) in a manner of sucking pressure fluid from 3. Axial piston device according to claim 2, wherein pressure fluid is additionally sucked through the throttle member (47). 4. Axial piston device according to any of the preceding claims, characterized in that the pressure fluid reservoir (48) consists of a leaking fluid collection chamber, in particular a housing interior (46) of the axial piston device (1). . 5. The turning device according to any one of claims 1 to 4, wherein the inclined plate or wobble plate 25 is between the first turning position corresponding to the large inclination angle and the second turning position corresponding to the small inclination angle. (31) can be pivoted back and forth, while the inclined plate or wobble plate (25) is rotated from the first pivot position to the second pivot position as pressure fluid flows out of the damping cylinder (42). Axial piston device, characterized in that the damping member (41) damps the pivoting movement. 6. The axial piston device (1) according to any one of claims 1 to 5, which is designed to have an inclined plate structure, and is provided in the cylinder cavities (3, 4) of the cylinder block (2). The piston (5, 6), which is supported on the inclined plate (25). 7. The axial piston device according to claim 6, wherein the damping member (41) is provided above or inside the inclined plate (25). 8. Axial piston device according to claim 7, characterized in that the damping piston (40) is held in contact with the stationary reverse member (30) opposed to the inclined plate (25) by the restoring spring (43). 7. Axial piston device according to claim 6, characterized in that the damping member (41) is provided above or inside the stationary reverse member (30) opposed to the inclined plate (25). 10. The axial piston device according to claim 9, wherein the damping piston (40) is held in contact with the inclined plate (25) by the restoring spring (43). The inclined plate 25 comprises first and second contact surfaces 28, 29 on opposite sides of the pistons 5, 6. The inclined plate 25 adopts the first pivot position having a large inclination angle while the first contact surface 28 is in contact, and the inclined plate 25 while the second contact surface 29 is in contact. ) Adopts the second pivot position having a small inclination angle. 12. The force F _DR exerted on the inclined plate 25 by the damping pistons 40a and 40b to the swinging device 31 during the swing. The combined force consisting of the force F _V applied to the inclined plate 25 and the force F _KL applied to the inclined plate 25 by the pistons 5 and 6 is the cylinder block shaft 12. In which the damping pistons 40a and 40b respectively act on the inclined plate 25 are biased relative to the cylinder block axis 12 in a manner that acts on the center S of the force located on Axial piston device, characterized in that.