Control Plate for an Axial Piston Machine, and an Axial Piston Machine comprising a Control Plate

Abstract

A control plate for an axial piston machine is disclosed. The control plate includes a control face on which at least one kidney-shaped high-pressure control opening extending axially through the control plate and at least one kidney-shaped low-pressure control opening extending axially through the control plate is formed and which defines a first sealing ridge which is formed radially inside the at least one high-pressure control opening and the at least one low-pressure control opening, and a second sealing ridge which is formed radially outside the at least one high-pressure control opening and the at least one low-pressure control opening. In this case, the second sealing ridge is wider in the radial direction, preferably in some portions, than the first sealing ridge. Additionally, an axial piston machine in a swash plate design is disclosed. The axial piston machine includes a control plate which has at least one kidney-shaped high-pressure control opening and at least one kidney-shaped low-pressure control opening, by way of which piston recesses of a cylinder drum which is rotatably mounted in a housing of the axial piston machine can be connected alternately to a high-pressure connection and a low-pressure connection during rotation of the cylinder drum. In this case, a first, radially inner sealing ridge and a second, radially outer sealing ridge, which is designed to be wider in the radial direction, preferably in some portions, than the first sealing ridge, are formed on a contact face between the control plate and the cylinder drum.

Claims

1. A control plate for or of an axial piston machine, comprising: a control face in which are formed (i) at least one kidney-shaped high-pressure control opening extending axially through the control plate, and (ii) at least one kidney-shaped low-pressure control opening extending axially through the control plate, wherein the control face defines (i) a first sealing ridge which is radially inner relative to the at least one kidney-shaped high-pressure control opening and the at least one kidney-shaped low-pressure control opening, and (ii) a second sealing ridge which is radially outer relative to the at least one kidney-shaped high-pressure control opening and the at least one kidney-shaped low-pressure control opening, and wherein the second sealing ridge is wider in the radial direction in at least some portions than the first sealing ridge.

2. The control plate according to claim 1, wherein the second sealing ridge is wider in the radial direction at least in the region of the at least one kidney-shaped high-pressure control opening than the first sealing ridge.

3. The control plate according to claim 1, wherein the second sealing ridge has a radially outwardly directed extension at least in the region of the at least one kidney-shaped high-pressure control opening.

4. The control plate according to claim 1, wherein: in the radial direction, the control plate has a first portion, a second portion and a third portion, and the second portion has a greater thickness in the axial direction than the first portion and the third portion.

5. The control plate according to claim 4, wherein the control face is formed in the second portion.

6. The control plate according to claim 1, wherein the at least one kidney-shaped high-pressure control opening includes a plurality of kidney-shaped high-pressure control openings having different dimensions.

7. An axial piston machine, comprising: a housing; a cylinder drum rotatably mounted in the housing; and a control plate which has at least one kidney-shaped high-pressure control opening and at least one kidney-shaped low-pressure control opening, by way of which piston recesses of the cylinder drum are configured to be connected alternately to a high-pressure connection and a low-pressure connection during rotation of the cylinder drum, wherein, on a contact face between the control plate and the cylinder drum, a radially inner, first sealing ridge and a radially outer, second sealing ridge are formed, which is wider in the radial direction, in some portions, than the first sealing ridge.

8. The axial piston machine according to claim 7, wherein the first sealing ridge and the second sealing ridge are formed on the control plate.

9. The axial piston machine according to claim 7, wherein the first sealing ridge and the second sealing ridge are formed on an end face of the cylinder drum in contact with the control plate.

10. The control plate according to claim 1, wherein the control face is an annular control face.

11. The control plate according to claim 1, wherein the second sealing ridge is wider in the radial direction exclusively in the region of the at least one kidney-shaped high-pressure control opening than the first sealing ridge.

12. The control plate according to claim 1, wherein the second sealing ridge has a radially outwardly directed extension exclusively in the region of the at least one high-pressure control opening.

13. The control plate according to claim 1, wherein the at least one kidney-shaped high-pressure control opening includes four kidney-shaped high-pressure control openings having different dimensions.

14. The axial piston machine of claim 7, wherein the axial piston machine possesses a swash plate design.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the following, one preferred exemplary embodiment of an axial piston machine comprising a control plate according to the disclosure will be described in greater detail with reference to the accompanying drawings, in which:

[0020] FIG. 1 is a longitudinal sectional view of an axial piston machine,

[0021] FIG. 2 is a perspective view of a cylinder drum according to the disclosure according to one preferred exemplary embodiment, and

[0022] FIG. 3 is a perspective view of a control plate according to the disclosure according to the preferred exemplary embodiment.

DETAILED DESCRIPTION

[0023] FIG. 1 is a longitudinal sectional view of an axial piston machine 1. In this case, the axial piston machine 1 is in the form of a pump or motor in a swash plate design. The axial piston machine 1 comprises a drive mechanism assembly 3 which is arranged so as to be able to rotate about an axis of rotation 2 and which has a cylinder drum 4 which is provided with a plurality of piston recesses 5 arranged concentrically with a central axis of rotation 2, preferably in the form of cylinder bores. One piston 6 is mounted in a longitudinally displaceable manner in each of the piston recesses 5.

[0024] Furthermore, the drive mechanism assembly 3 comprises a drive shaft 7 which is guided through an opening/bore in the cylinder drum 4 concentrically with the central axis of rotation 2.

[0025] The drive shaft 7 and consequently the drive mechanism assembly 3 are further rotatably accommodated in a housing 8 of the axial piston machine 1. The housing 8 in turn consists of two housing parts which are axially screwed to one another and which together define a receiving cavity for the drive mechanism assembly 3. In the exemplary embodiment shown in FIG. 1, the housing 8 is specifically composed of a housing pot 8a and a corresponding housing lid 8b, and therefore the hollow or receiving cavity is thus formed in the housing interior to receive the drive mechanism assembly 3, and the drive shaft 7 extends through an opening in the housing pot 8a formed concentrically with the axis of rotation 2 on an outer face of the housing 8.

[0026] In order to support the drive mechanism assembly 3 or the drive shaft 7 supporting this assembly in a rotationally fixed manner, two bearing points 9, 10 in the form of tapered roller bearings are arranged.

[0027] In this case, a bearing point 9 is arranged in the region of the above-mentioned opening for the feedthrough of the drive shaft 7 in the housing pot 8a, whereas the other bearing point 10 is formed in the housing lid 8b. In order to seal the housing 8, a sealing element in the form of a radial shaft sealing ring 11 is additionally arranged in the region of the one bearing point 9.

[0028] As shown in FIG. 1, the cylinder drum 4 comprises an inner toothing 12 which is engaged with an outer toothing 13 formed on the drive shaft 7. In other words, the cylinder drum 4 is connected to the drive shaft 7 in a rotor-synchronous but axially displaceable manner. Furthermore, the drive mechanism assembly 3 comprises a spring 14 in the form of a (helical) compression spring 14 which prestresses the cylinder drum 4 against the drive shaft 7 in such a way that the cylinder drum 4 is pressed towards the housing lid 8b relative to the drive shaft 7 in order to hold a control plate 15, which is described in greater detail below and is arranged in a direction of the central axis of rotation (axial direction) between the cylinder drum 4 and the housing lid 8b, in contact with the housing lid 8b. In other words, the spring 14 is designed to press the control plate 15 against the housing lid 8b by way of the cylinder drum 4.

[0029] The pistons 6 mentioned above are each connected at the end portion (piston head) thereof facing away from the housing lid 8b by way of a ball joint to a support element 16 in the form of a sliding block and are supported on a swash plate 17 by way of these support elements 16. The swash plate 17 which is at a slant relative to the axis of rotation 2 can be integrally formed on the housing 8 or fastened thereto in a rotationally fixed manner so that the axial piston machine 1 has a fixed displacement volume. However, it is also conceivable to design the swash plate 17 to have an adjustable inclination with respect to the axis of rotation 2, by way of which the displacement volume of the axial piston machine 1 can be made adjustable/variable.

[0030] The support elements 16 formed by the sliding blocks are pressed against the swash plate 17 by an annular-disk-shaped hold-down plate 18, which rotates together with the cylinder drum 4 but is held by the housing by way of a shaft ring and is thus prevented from lifting off from the swash plate 17.

[0031] In the exemplary embodiment shown, an end face of the cylinder drum 4 is supported on a control face 19 fixed to the housing in the direction of the axis of rotation. In this case, the control face 19 is formed on the control plate 15. The above-mentioned control plate 15 shown in isolation in FIG. 3 is in turn held on the housing lid 8b in a rotationally fixed manner.

[0032] As shown in FIG. 2, the cylinder drum 4 comprises, on the end face thereof which is in contact with the control plate 15, kidney-shaped connecting openings 20 distributed over the circumference, which are each assigned to a piston recess 5. In other words, one connecting opening 20 is formed for each piston recess 5.

[0033] FIG. 3 shows the control plate 15 according to the preferred exemplary embodiment. The control plate 15 designed with a preferably circular outer contour has, in the radial direction from the inside outward, a first portion 21, a second portion 22 and a third portion 23, wherein the plate thickness/material thickness of the first portion 21 and the third portion 23 is smaller than the plate thickness of the second portion 22. In other words, the second portion 22 is formed in the manner of a planar projection and protrudes in the axial direction from the first portion 21 and the third portion 23.

[0034] Furthermore, the control plate 15, as shown in FIG. 3, comprises a low-pressure control opening/control nodule 24 and at least one, in particular four, high-pressure control openings/control nodules 25. In other words, in the control plate 15, the low-pressure control opening 24 is formed on a low-pressure side (at the bottom of FIG. 3), and the four high-pressure control openings 25 are formed on a high-pressure side (at the top of FIG. 3). The low-pressure control opening 24 and the high-pressure control openings 25 are in the form of kidney-shaped through-openings, wherein in the preferred exemplary embodiment, the size, that is to say the extent in the circumferential direction, of the high-pressure control openings 25 varies. In particular, in this case, two of the high-pressure control openings 25 are smaller than the two other high-pressure control openings 25.

[0035] As shown in FIG. 3, the second portion 22 has, on the high-pressure side, i.e. in the region of the high-pressure control openings 25, an extension (cam) 26 protruding in the radial direction and extending in the circumferential direction, so that, in the region of the extension 26, the second portion 22 has a greater width in the radial direction. As a result of the widening of the second portion 22 on the high-pressure side, the higher mechanical load in this region can be better compensated for. In addition, in this region, a higher pressure-relief force can be generated in a locally limited manner. By way of this local increase, the strain relief can be increased, and the radius of the residual force can simultaneously be reduced (especially locally at the extreme value). If the widening 26 were to extend over a greater region, the application point of the residual force would migrate further outward in the radial direction. As a result, the pressure-relief force increases again, but the cylinder drum 4 tends to tilt much more quickly.

[0036] If the cylinder drum 4, as mentioned previously, is then pressed against the control plate 15 and the housing lid 8b by the spring 14, the end face of the cylinder drum 4 comes into contact exclusively with the second portion 22 of the control plate 15. During rotation of the drive shaft 3 and consequently the cylinder drum 4, the piston recesses 5 selectively come into fluid contact, via the connecting openings 20 and the low-pressure control opening 24 and the high-pressure control openings 25, with a high-pressure connection/inlet side, for example in the form of a suction duct 27, and a low-pressure connection/outlet side (not shown in FIG. 1).

[0037] During operation, the connections/fluid ducts between the piston recesses 5 and the inlet or outlet side must be sealed. At the same time, in order to reduce the frictional resistance between the rotating cylinder drum 4 and the control plate 15 fixed to the housing, a lubricating film is to be produced. For this purpose, the control plate 15 and in particular the control face 19 must have a high surface quality. Because only the second portion 23 of the control plate 15 is in contact with the cylinder drum 4, i.e. only the second portion 23 forms the control face 19, it is also only necessary to refinish this portion 23 separately, for example by additional lapping, to ensure the high surface quality.

[0038] As mentioned previously, during operation, the second portion 23 must ensure sealing between the cylinder drum 4 and the control plate 15. In other words, the second portion 23 forms a first, radially inner sealing ridge 28, and a second, radially outer sealing ridge 29, wherein the low-pressure control opening 24 and the high-pressure control openings 25 are formed in the radial direction between the first sealing ridge 28 and the second sealing ridge 29. As shown in FIG. 3, in this case the width of the first sealing ridge 28 is constant over the entire circumference, whereas the second sealing ridge 29 has a smaller width on the low-pressure side than on the high-pressure side. As mentioned previously, the second sealing ridge 29 forms the extension 26 on the high-pressure side. Because the first sealing ridge 28 has a constant width over the entire circumference, the low-pressure control opening 24 and the high-pressure control openings 25 are displaced in the radial direction inward as far as possible, which reduces the centrifugal forces into the control openings 24, 25 and thus allows high rotational speeds.

[0039] According to the preferred exemplary embodiment, the control plate 15 is fixed to the housing 8 in a stationary manner. In addition, the inner circumference of the control plate 15 is supported on an outer bearing ring of the bearing point 10. Furthermore, the control plate 15 comprises a plurality of, in particular two grooves 30 on the inner circumference thereof, which grooves are used for example for centering with a centering element, in particular an alignment pin, fixed to the bearing ring of the bearing point 10, and/or for discharging leakage oil out of the region of the spring 14.

[0040] In the preferred exemplary embodiment described previously, the sealing ridges 28, 29 are formed on the control face 19 of the control plate 15, and the end face of the cylinder drum 4 has a planar design. Of course the end face of the cylinder drum 4 can also comprise the sealing ridges 28, 29, and the control face 19 of the control plate 15 can have a planar design.

[0041] A control plate for an axial piston machine in a swash plate design is disclosed, comprising a control face which has at least one kidney-shaped high-pressure control opening and at least one kidney-shaped low-pressure control opening, by way of which piston recesses of a cylinder drum rotatably mounted in a housing of the axial piston machine can be alternately connected to a high-pressure connection and a low-pressure connection during rotation of the cylinder drum, and a first sealing ridge which is formed radially inside the at least one high-pressure control opening and the at least one low-pressure control opening, and a second sealing ridge formed radially outside the at least one high-pressure control opening and the at least one low-pressure control opening. In this case, the second sealing ridge is wider in the radial direction, preferably in some portions, than the first sealing ridge.

[0042] Additionally, an axial piston machine in a swash plate design is disclosed, comprising a control plate which has at least one kidney-shaped high-pressure control opening and at least one kidney-shaped low-pressure control opening, by way of which piston recesses of a cylinder drum which is rotatably mounted in a housing of the axial piston machine can be connected alternately to a high-pressure connection and a low-pressure connection during rotation of the cylinder drum. In this case, a first, radially inner sealing ridge and a second, radially outer sealing ridge, which is designed so as to be wider in the radial direction, preferably in some portions, than the first sealing ridge, are formed on a contact face between the control plate and the cylinder drum.