AT518318B1 - axial piston pump - Google Patents

Abstract

The invention relates to an axial piston pump (1) - in particular swash plate pump - with a plurality of pistons (30a, 30b, 30c) which are arranged displaceably in each case in a cylinder (40a, 40b, 40c) parallel to an axis (6) of the axial piston pump (1) in which the cylinders (40a, 40b, 40c) each have at least one high-pressure line (23a, 23b, 23c) each with one high-pressure valve (52a, 52b, 52c) and one low-pressure line (22a, 22b, 22c), each with one low-pressure valve (51a, 51b, 51c) are flow-connected and wherein the low-pressure valves (51a, 51b, 51c) and the high-pressure valves (52a, 52b, 52c) are each arranged along a valve axis (50) in a respective valve chamber (53), wherein the valve axes (50) are arranged substantially parallel to the axis (6) of the axial piston pump (1). The object of the invention is to provide an easy to manufacture axial piston pump (1). This is achieved according to the invention in that the cylinders (40a, 40b, 40c) are arranged in a housing (7) divided by a dividing plane (8) into a first housing part (10) and a second housing part (20), and a low-pressure collecting space ( 4) is arranged starting from the dividing plane (8), which is arranged in particular partially in the first housing part (10) and partially in the second housing part (20), wherein the low-pressure accumulation chamber (4) is preferably formed as a groove.

Description

The invention relates to an axial piston pump - in particular swash plate pump - with a plurality of pistons, which are arranged displaceably in each case parallel to an axis of the axial piston pump, the cylinders via at least one high-pressure line, each with a high-pressure valve and a low-pressure line each are flow-connected to a low-pressure valve and wherein the low-pressure valves and the high-pressure valves are each arranged along a valve axis in a respective valve chamber, wherein the valve axes are arranged substantially parallel to the axis of the axial piston pump.

Axial piston pump of this type are usually used as hydraulic pumps. The valve axes of the valve chambers are usually arranged normal to the axis of the axial piston pump. This is disadvantageous for the production, since the valve chambers must be accurately manufactured with the valve seats and the workpiece must be re-clamped to bore the valves after drilling the cylinder.

From US 3,018,737 A, an axial piston pump is known which is designed as a swash plate pump with a plurality of pistons. In this case, this axial piston pump has a substantially one-piece housing in which the valves are arranged along a valve axis in a separate component parallel to the axis of the axial piston pump. Along the piston three sealing rings are arranged. In between is a hole to the outside to drain leaks. A disadvantage of this design, however, is that leaks are not collected at all and, therefore, large leakage of fluid from the axial piston pump occurs in the event of a major leakage of the first seal along the piston. The supply line to the valves takes place in this pump via a flanged component. In the flange, therefore, several seals must again be arranged to prevent leakage of the liquid.

Object of the present invention is now to provide an axial piston pump which avoids these disadvantages and in which the geometry enables a simple and accurate production.

According to the invention, this object is achieved in that the cylinders are arranged in a divided by a dividing plane in a first housing part and a second housing part housing, and a low-pressure accumulation chamber is arranged starting from the dividing plane, in particular partially in the first housing part and partially in the second housing part is arranged, wherein the low-pressure accumulation space is preferably formed as a groove. Thus, for a particularly simple and fast production, all important cylindrical recesses in the housing can be machined from the parting plane. And thus, the low-pressure accumulation space can be manufactured with the cylinders and the valve spaces.

Substantially parallel means that the arrangement is still considered to be parallel with a deviation of up to about 5 °. However, exact parallelism is to be preferred in any case.

The usual arrangement, in which the valve axes are arranged normally on the axis of the axial piston pump, makes it possible that the flow paths remain simple. Due to the parallel arrangement, the problem arises of complicated flow paths in the axial piston pump. The present invention provides a simple arrangement in the housing. At the same time a better control of the leakage is achieved.

The same advantage arises when a high-pressure accumulator starting from the dividing plane is arranged in the housing, which is preferably designed as a groove.

It is advantageous if a first connection bore is provided, which is connected to the low-pressure plenum, wherein the first connection bore is arranged parallel to the axis of the axial piston pump and if a second connection bore is provided, which is connected to the high-pressure accumulation chamber, wherein the second connection bore is arranged parallel to the axis of the axial piston pump. As a result, the connection holes can be arranged as compact as possible in the housing.

So that all fluid-carrying parts are housed in the housing, it is advantageous if the cylinders are arranged starting from the dividing plane completely in the first housing part and the second housing part.

For safe guidance of the piston, it is favorable if at least one cylinder has a first piston guide surface in the first housing part and a second piston guide surface in the second housing part and the first piston guide surface and the second piston guide surface are each arranged in the end regions facing away from the dividing plane of the cylinder and a sealing space is disposed between the end portions of the cylinder.

In order to prevent a possible leakage through the cylinder, it is advantageous if the sealing space is arranged across the dividing plane in the cylinder.

The same advantage arises when a receiving element for at least one seal is arranged in the sealing space.

If the receiving element has a first seal receptacle and a second seal receptacle, more seals along the cylinder axis can be provided in the cylinder, which further increases the security against leakage.

Thus, the fluid can be conveyed back into the pressure chamber at a leak, it is advantageous if the first seal holder and / or the second seal receiving at least two radial bores and preferably three radial bores, wherein at least one radial bore with a Low-pressure accumulator is fluidly connected.

Better tightness is advantageously obtained in an embodiment in which in the seal chamber around the piston at least two - preferably three - are arranged sealing rings.

A more accurate production also results from when the valve chambers are arranged starting from the dividing plane in the first housing part and in the second housing part.

As a result, the invention will be explained in more detail with reference to the embodiment shown in FIGS. FIG. 1 shows an axial piston pump according to the invention in a schematic sectional representation; FIG. FIG. 2 shows a first housing part of the axial piston pump in a plan view; FIG. Fig. 3 shows the first housing part of the axial piston pump in a partial section along the line III-III in Fig. 2; FIG. 4 shows a second housing part of the axial piston pump in a plan view; FIG. 5 shows the second housing part of the axial piston pump in a partial section ge according to the line IV-IV in Fig. 4; FIG. 6 shows a first seal receptacle in a section according to the line VI-VI in FIG. 9; FIG. FIG. 7 shows a second seal receptacle in a section analogous to FIG. 6; FIG. FIG. 8 shows a third sealing ring; FIG. FIG. 9 shows the first seal receiver in plan view; FIG. FIG. 10 shows the first seal receptacle in an elevation; FIG. and FIG. 11 shows the housing of the axial piston pump in an elevation.

In Fig. 1, an axial piston pump 1 according to the invention is shown. Here, the sectional view of FIG. 3 is combined with the sectional view of FIG. 5.

The designed as a swash plate pump axial piston pump 1 has a first housing part 10 and a second housing part 20. Via a flange 2, the axial piston pump 1 can be connected to a drive, not shown. In the embodiment shown, three identical pistons 30a, 30b, 30c are moved back and forth in cylinders 40a, 40b, 40c via a swashplate 3.

By the cylinder 40a, 40b, 40c and the pistons 30a, 30b, 30c, a pressure chamber 21a, 21b, 21c in the second housing part 20 is formed depending on a respective low pressure line 22a, 22b, 22c, each with one along a valve axis 50 slidably disposed low pressure valve 51 a, 51 b, 51 c is fluidly connected. The low-pressure valves 51a, 51b, 51c are each connected via a first bore 11a, 11b, 11c and a second bore 12a, 12b, 12c to a low-pressure accumulator 4. Furthermore, each pressure chamber 21 a, 21 b, 21 c, each with a high pressure line 23 a, 23 b, 23 c connected to a high pressure valve 52 a, 52 b, 52 c. With a high pressure accumulator 5 each high pressure valve 52a, 52b, 52c via a respective third bore 13a, 13b, 13c and a fourth bore 14a, 14b, 14c fluidly connected.

The low pressure valves 51a, 51b, 51c and the high pressure valves 52a, 52b, 52c are slidably disposed in valve spaces 53 along the valve axes 50.

The pistons 30a, 30b, 30c and the cylinders 40a, 40b, 40c are arranged rotationally symmetrically about an axis 6 of the axial piston pump 1. Cylinder axes 41 of the cylinders 40a, 40b, 40c are arranged parallel to the axis 6. The valve axes 50 are also parallel to the axis 6.

The first housing part 10 and the second housing part 20 are parts of a housing 7, wherein this is divided by a dividing plane 8 in the first housing part 10 and the second housing part 20.

The high-pressure accumulator 5 and a first low-pressure accumulator 4a are arranged starting from the dividing plane 8 in the first housing part 10. In the second housing part 20, a second low-pressure accumulation chamber 4b is arranged starting from the dividing plane.

In the illustrated embodiment of the axial piston pump 1, the first low-pressure accumulator 4a and the second low-pressure accumulator 4b are arranged substantially symmetrically about the division plane 8.

From the first housing part 10 to the second housing part 20 of the high-pressure accumulation chamber 5 is limited by a sealing element 15. The high-pressure accumulator 5 is executed in the illustrated axial piston pump 1 as a groove. The groove widens towards the second housing part 20 towards wider. The seal member 15 is disposed in this groove at the extended position.

The first holes 11a, 11b, 11c and the third holes 13a, 13b, 13c start from the periphery of the axial piston pump 1 and are each closed by a closure element 16.

The second bores 12a, 12b, 12c start from the first low-pressure accumulation chamber 4a and the fourth bores 14a, 14b, 14c from the high-pressure accumulation chamber 5.

A first connection bore 24a is arranged in the first housing part 10 parallel to the axis 6. It intersects the low-pressure accumulation space 4. The first connection bore 24a and the low-pressure accumulation space 4 are thus flow-connected (FIG. 4).

The high-pressure accumulation chamber 5 is connected via a first high-pressure bore 17a, a second high-pressure bore 17b and a third high-pressure bore 17c to a second connecting bore 24b in the second housing part 20.

The first connection bore 24a and the second connection bore 24b start from a plane parallel to the plane of division, which is arranged away from the first housing part 10 on the second housing part 20.

Starting from the high-pressure accumulation chamber 5, a first connecting bore 18a is connected to a valve bore 19 (FIG. 2). In the valve bore 19, a pressure relief valve 54 is arranged. It opens in the direction of a second connecting bore 18b, which merges into a third connecting bore 25a in the second housing part 20. Via a fourth connection bore 25b and a fifth connection bore 25c, the pressure relief valve 54 is connected to the low-pressure accumulation chamber 4.

The fourth connection bore 25b and the second high-pressure bore 17b are closed with closure elements 16. The closure elements 16 are screwed in the embodiment shown in the respective holes.

The axial piston pump 1 has per cylinder 40a, 40b, 40c a receiving element 60 for seals. The receiving element 60 is divided by a plane 80 parallel to the dividing plane 8 or normal to the cylinder axis 41 into a first seal seat 61 and a second seal seat 62.

The first seal receptacle 61 is in the cylinder 40 in the first housing part 10 and the second seal receiver 62 is partially disposed in the cylinder 40 in the first housing part 10 and partially in the cylinder 40 in the second housing part 20.

The first seal receiver 61 and the second seal receiver are arranged coaxially in the cylinder 40 along the cylinder axis 41. They have a cylindrical outer contour which corresponds to the inner contour of the cylinder 40.

The first seal receiver 61 (FIG. 6) has a first receiver 63a in which a first seal ring 64a is arranged. At the periphery, the first seal receptacle 61 has a first groove 65a in which a first O-ring 66a is arranged.

The second seal receiver 62 (FIG. 7) has a second receiver 63b for a second seal ring 64b. A second O-ring 66b is disposed in a second groove 65b on the periphery of the second seal receiver 62.

Turning to the division plane 8, the first seal holder 61 has a third groove 67, which forms a low-pressure collecting space 4c. From the bottom of the third groove 67, in the embodiment shown, three radial bores 68a are distributed around the circumference, which extend as far as a cylindrical inner surface 69 in the interior of the first seal receiver 61 (FIG. 9).

The same radial holes 68b, the second seal receiver 62 (Fig. 7). The second seal receiver 62 has a shoulder 70 which extends from a cylinder jacket surface 71 with a diameter D to a jacket surface 72 with a smaller diameter d. The three radial bores 68 b emerge from the lateral surface 72 on the second seal receiver 62.

The radial bores 68b of the second seal receiver 62 are arranged along bore axes 73b which lie in the division plane 8.

The lateral surface 72 and a shoulder surface 74 of the second seal receptacle 62 form, with the first housing part 10 and the second housing part 20, the boundary of the low-pressure collecting space 4.

From the dividing plane 8 away in the direction of the second housing part 20, a third sealing ring 64c is arranged concentrically with the first seal seat 61 and the second seal seat 62.

The low-pressure valves 51 a, 51 b, 51 c and the high-pressure valves 52 a, 52 b, 52 c are substantially non-return valves and each have a valve body 55 and a valve spring 56.

By a guide plate 31 which is supported by a spring 32 against the first housing part 10 of the housing 7, the piston 30 are biased against the swash plate 3.

2, the plan view of the first housing part 10 is shown. The first housing part 10 has a leakage line 42a, 42b, 42c for each cylinder 40a, 40b, 40c. Line axes 43 of the leakage lines 42 in the first housing part 10 lie in a leakage plane 9 in which also bore axes 73a of the radial bores 68a of the first seal seat 61 are located.

From FIG. 3 and FIG. 5, it can be seen that the first housing part 10 and the second housing part 20 have elevations 57 to the valve spaces 53.

For the function of the axial piston pump 1, the path of the fluid will be explained in the following: [0061] Through the first connection bore 24a, the fluid is conducted into the low-pressure collecting space 4. From the low-pressure accumulation chamber 4, it continues to flow through the second bores 12a, 12b, 12c and through the first bores 11a, 11b, 11c into the low-pressure valves 51a, 51b, 51c.

Of the low pressure valves 51a, 51b, 51c, the fluid flows further into the pressure spaces 21a, 21b, 21c through the low pressure lines 22a, 22b, 22c in which it displaces from the pistons 30a, 30b, 30c, and so on through the high pressure lines 23a, 23b, 23c is pumped to the high pressure valves 52a, 52b, 52c. From the high-pressure valve 52a, 52b, 52c, the fluid continues to flow through the third bores 13a, 13b, 13c and the fourth bores 14a, 14b, 14c into the high-pressure accumulation chamber 5. From there through the first high-pressure bore 17a, further through the second high-pressure bore 17b and the third high pressure bore 17c to the second connection bore 24b.

In the second connection hole 24b, a pipe, not shown, can be screwed, which serves to dissipate the fluid. Analogously, a supply line into the first connection bore 24a is possible.

In the event of leakage of the third sealing ring 64c of one of the pressure chambers 21a, 21b, 21c, the fluid is passed through one of the three radial bores 68b of the second seal receiver 62 into the low-pressure reservoir 4.

In a further fluid flow over the piston 30a, 30b, 30c and a leakage of the second seal ring 64b, the fluid is passed through one of the three radial holes 68a in the low-pressure accumulation chamber 4c and on to the respective leakage line 42. Between the swash plate 3 and the three radial bores 68a, a first sealing ring 64a is still arranged.

As a result, the fluid can only reach the swash plate 3 when the third sealing ring 64c, the second sealing ring 64b and the first sealing ring 64a are overcome.

In the event that too high a pressure in the high-pressure accumulation chamber 5 prevails, the fluid flows through the first connecting hole 18 a and the second connecting hole 18 b to a valve bore 19 in which the pressure relief valve 54 is arranged. When the relief valve 54 opens, the fluid flows via the third communication hole 25a to the fourth communication hole 25b to the fifth communication hole 25c, and thus enters the low pressure accumulation space 4.

For guiding the piston 30a, 30b, 30c, the first housing part 10 has a first piston guide surface 74a and the second housing part 20 has a second piston guide surface 74b. These are arranged in the cylinder (40a, 40b, 40c) in an end region 44a in the first housing part 10 and in an end region 44b in the second housing part 20. The first piston guide surface 74a is formed by a through hole, and the second piston guide surface 74b extends in the embodiment shown to the pressure chamber 21a, 21b, 21c.

In the area of the division plane 8, a sealing space 45 is provided in the cylinder 40a, 40b, 40c. The seal space 45 is located between the first piston guide surface 74a and the second piston guide surface 74b. In this seal chamber 45, the receiving member 60 with the first seal holder 61 and the second seal holder 62 and the third seal ring 64 c are arranged.

Claims (13)

claims 1. Axial piston pump (1) - in particular swash plate pump - with a plurality of pistons (30a, 30b, 30c) which are arranged displaceably in each case a cylinder (40a, 40b, 40c) parallel to an axis (6) of the axial piston pump (1) the cylinders (40a, 40b, 40c) via at least one high-pressure line (23a, 23b, 23c) each having a high-pressure valve (52a, 52b, 52c) and a respective low pressure line (22a, 22b, 22c) each having a low pressure valve (51a , 51b, 51c) and wherein the low-pressure valves (51a, 51b, 51c) and the high-pressure valves (52a, 52b, 52c) are each arranged along a valve axis (50) in a respective valve chamber (53), the valve axes (50 ) are arranged substantially parallel to the axis (6) of the axial piston pump (1), characterized in that the cylinders (40a, 40b, 40c) in a through a dividing plane (8) in a first housing part (10) and a second housing part (20) divided housing (7) are arranged, and a Niederdrucksamme Lraum (4) starting from the dividing plane (8) is arranged, which is in particular partially in the first housing part (10) and partially in the second housing part (20), wherein the low-pressure accumulation chamber (4) is preferably formed as a groove. 2. Axialkolbenpumpe (1) according to claim 1, characterized in that a first connection bore (24 a) is provided, which is connected to the low-pressure accumulation chamber (4), wherein the first connection bore (24 a) parallel to the axis (6) of the axial piston pump ( 1) is arranged. 3. axial piston pump (1) according to one of claims 1 to 2, characterized in that a high-pressure accumulation chamber (5) from the dividing plane (8), starting in the housing (7) is arranged, which is preferably formed as a groove. 4. axial piston pump (1) according to claim 3, characterized in that a second connection bore (24b) is provided, which is connected to the high-pressure accumulation chamber (5), wherein the second connection bore (24b) parallel to the axis (6) of the axial piston pump ( 1) is arranged. 5. axial piston pump (1) according to one of claims 1 to 4, characterized in that the cylinders (40a, 40b, 40c) from the dividing plane (8), starting completely in the first housing part (10) and the second housing part (20) are. 6. axial piston pump (1) according to one of claims 1 to 5, characterized in that at least one cylinder (40a, 40b, 40c) a first piston guide surface (74a) in the first housing part (10) and a second piston guide surface (74b) in the second housing part (20). 7. axial piston pump (1) according to claim 6, characterized in that the first piston guide surface (74a) and the second piston guide surface (74b) in each of the dividing plane (8) facing away from end portions (44a, 44b) of the cylinder (40a, 40b, 40c) and between the end regions (44a, 44b) of the cylinder (40a, 40b, 40c) a sealing space (45) is arranged. 8. axial piston pump (1) according to claim 7, characterized in that the sealing space (45) over the dividing plane (8) in the cylinder (40a, 40b, 40c) is arranged. 9. axial piston pump (1) according to one of claims 7 to 8, characterized in that in the sealing space (45) a receiving element (60) is arranged for at least one seal. 10. Axial piston pump (1) according to claim 9, characterized in that the receiving element (60) has a first seal receptacle (61) and a second seal receptacle (62). 11. axial piston pump (1) according to claim 10, characterized in that the first seal receptacle (61) and / or the second seal receptacle (62) at least two radial bores (68a, 68b) and preferably three radial bores (68a, 68b), wherein at least one radial bore (68a, 68b) is fluidly connected to a low pressure accumulation space (4, 4c). 12. axial piston pump (1) according to one of claims 7 to 11, characterized in that in the seal chamber (45) around the piston (30a, 30b, 30c) at least two - preferably three - sealing rings (64a, 64b, 64c) are arranged. 13. axial piston pump (1) according to one of claims 1 to 12, characterized in that the valve chambers (53) of the dividing plane (8) starting in the first housing part (10) and in the second housing part (20) are arranged.