CN111102150B

CN111102150B - Distribution plate for hydrostatic axial piston machine and hydrostatic axial piston machine

Info

Publication number: CN111102150B
Application number: CN201910954066.7A
Authority: CN
Inventors: M.泽尔; S.霍普; S.豪格; T.纳夫斯
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-10-10
Filing date: 2019-10-09
Publication date: 2023-10-27
Anticipated expiration: 2039-10-09
Also published as: CN111102150A; DE102018217303A1

Abstract

A distributor plate for a hydrostatic axial piston machine and a corresponding axial piston machine are disclosed. The high-pressure kidney of the distributor plate has one or more webs, by means of which the high-pressure kidney is divided into two or more likewise kidney-shaped perforations. Since the at least one web coincides on the cylinder side with the cylinder-side contact surface of the distributor plate, only a minimal lubricating gap is also produced between the web and the cylinder, in which lubricating gap a lubricating film forms. In order to avoid attenuations, such as necks, in the lubricating film, the web is penetrated by one or more channels. The pressure medium reaches the lubrication gap as a supplemental lubricant from the high-pressure channel of the axial piston machine through the distributor plate via the one or more channels.

Description

Distribution plate for hydrostatic axial piston machine and hydrostatic axial piston machine

Technical Field

The invention relates to an optimization of hydrostatic pressure relief and lubrication gaps between distributor plates and cylinders of an axial piston machine of swash plate construction. The invention further relates to a corresponding axial piston machine.

Background

In the case of axial piston machines of swash plate construction, a surrounding cylinder tube, in which the pistons are guided in the axial direction, is pressed on the end face against a stationary distributor plate, which can also be referred to as a control plate or oil distribution plate (steuerstpixel). The circumferential inlet openings of the cylinder must in this case alternately bear as tightly as possible against two circular-arc-shaped connecting kidneys (veribindigsnieren) of the distributor plate. The two connecting kidneys are referred to below simply as kidneys. In operation of the axial piston machine, one of the two kidneys serves to connect the surrounding access opening to the high-pressure connection of the axial piston machine and is therefore (temporarily or permanently) referred to as a high-pressure kidney, while the other kidney is referred to as a low-pressure kidney.

For reasons of stability of the distributor plate, radial webs are often provided in the high-pressure kidney, which divide the high-pressure kidney into a plurality of individual perforations. If the axial piston machine concerned is designed for pressure side replacement, both kidneys must be designed for high pressure. In this case, the distributor plate is then often mirror-symmetrical and both kidneys have webs.

Publication KR 10-0872112 describes a distributor plate for an axial piston machine, the high-pressure kidney of which is divided into three oblong perforations by means of two webs. The webs are arranged such that the three perforations are not equally long. The thickness of the connecting plate is smaller than that of the distributing plate. The high-pressure kidney thus has a recess over its entire length towards the cylinder, said recess including all three perforations. A disadvantage of such a distributor plate is its manufacturing cost.

US 3,249,061 describes a mirror-symmetrical distributor plate for an axial piston machine, wherein two kidneys are each divided into three oblong perforations. The middle perforation of each kidney is longer than the two outer perforations.

DE 10 2015 224 129 A1 describes a distributor plate for an axial piston machine, whose corresponding high-pressure kidney has four webs and correspondingly five oblong perforations. These five perforations are as long.

For the distributor plate of the last-mentioned two publications, no recesses are provided for connecting all the perforations on the cylinder side, which are too costly in terms of production technology. Thus, the thickness of the web corresponds to the thickness of the distribution plate.

In order to be able to rotate the cylinder with respect to the distributor plate with low wear while simultaneously performing a sealing compression, a hydrostatic relief and a lubricating film (Tribokontakt) are provided between the distributor plate and the cylinder. The hydrostatic relief and the lubricating film extend beyond the slot-like opening into the lubricating gap between the cylinder barrel and the distributor plate.

A disadvantage of axial piston machines with such distributor plates is that radial narrowings or necks of the lubricating film are produced on the adapter plates.

Another problem is that the cylinder is easily tilted with respect to the distribution plate. The reason for this is, on the one hand, the pressing force, the level and the center of gravity of which vary as a function of the circumferential angular position. Acting against this is a hydrostatic relief and a pressure-loaded lubricating film, which also vary with the circumferential angular position.

Disclosure of Invention

In contrast, the object of the present invention is to provide a distributor plate with at least one technically simple connecting plate and a corresponding axial piston machine, for which the disadvantages of lubricant film formation in the connecting plate region are avoided.

The object of the invention is to compensate, in addition, for horizontal fluctuations in load and/or fluctuations in the two centers of gravity relative to one another. Thus, the configuration of the lubrication gap should become more uniform and volume losses and critical contact forces should be avoided. Thus, a reduction in wear and an improvement in efficiency or performance of the axial piston machine concerned should be achieved.

This object is achieved by a distributor plate having the features according to the invention and an axial piston machine having the features according to the invention.

Other advantageous embodiments include: the distributor plate is penetrated by a further channel in the region of the web or wherein the web is penetrated by a further channel; wherein the two channels; are arranged on a common circular arc; wherein the first connecting kidney has four perforations of equal length, and wherein the two connecting kidneys are mirror images of each other; wherein one of the two channels is arranged on the radially inner circular arc-shaped edge of the first connecting kidney and the other of the two channels is arranged on the radially outer circular arc-shaped edge of the first connecting kidney; having another web longer than the first mentioned web; wherein the at least one web comprises a first web, a second web and a third web, wherein the first connecting kidney has one longer perforation and three shorter perforations, and wherein three channels are provided in the first web, and wherein a channel is provided in the second web arranged between the first and second shorter perforations, and wherein two channels are provided in the third web arranged between the middle and last shorter perforations; wherein the at least one channel is a bore, and wherein the radial width of the channel is the diameter of the bore; wherein a transition hole is provided in the second connecting kidney, the diameter of the drilled hole corresponding to the diameter of the transition hole; wherein the diameter of the bore corresponds to between 5% and 20% of the radial width of the first connecting kidney.

The distributor plate of the claims can also be referred to as a control disk or oil distribution disk and is designed for hydrostatic axial piston machines of swash plate construction. The distributor plate has a circular-arc-shaped first and second connecting kidney, by means of which the side of the distributor plate that can be brought into contact with the cylinder and the side opposite thereto are connected. At least the first connecting kidney is divided by at least one web into at least two perforations and is therefore designed for high pressure. The cylinder-side surface of the connecting plate is in a plane with the cylinder-side surface of the distributor plate. The opposite side of the web can also lie in a plane with the corresponding opposite side of the distributor plate. The web then has the same thickness as the distributor plate. According to the invention, the distributor plate is penetrated by at least one channel in the region of the first web. The radial width of the channel is smaller than the radial width of the first connecting kidney. In the installed state of the distributor plate, the cylinder-side inlet of the channel is thus fluidically connected to the bore and to the assigned first working channel of the axial piston machine and is thus acted upon by a pressure medium. Thus, it is possible to prevent occurrence of a shortage of lubrication film formation, such as a necked-down portion (narrowed lubrication film formation), on the cylinder side surface of the joint plate.

The channel can be arranged between the radially inner circular arc-shaped edge of the first connecting kidney and the radially outer circular arc-shaped edge and thus extend through the web. The pressure medium of the first working channel thus passes through the channel directly to the critical cylinder-side of the web between the two bores, where it is faced with the constriction. Thus reducing or preventing necking.

The at least one channel can also be arranged radially inside the radially inner circular arc-shaped edge of the first connecting kidney or radially outside the radially outer circular arc-shaped edge of the first connecting kidney.

In a preferred development, the distributor plate is penetrated by a further channel in the region of the connecting plate. It is particularly preferred that the further channel also extends through the web. The pressure medium of the first working channel thus also reaches directly via the other channel to the critical cylinder-side of the web between the two bores, where it is faced with the constriction. Thus optimally preventing the necked-down portion.

In one variant, the two channels are arranged on an arc extending with the surrounding of the access opening, preferably centrally between the two perforations.

In a particularly preferred embodiment of the first variant, the distributor plate is mirror-symmetrical and the two connecting kidneys each have four equally long perforations.

One of the two channels can be arranged on the radially inner circular arc-shaped edge of the first connecting kidney, while the other of the two channels is arranged on the radially outer circular arc-shaped edge of the first connecting kidney. In detail, the two channels open onto the mentioned edge.

In one embodiment known per se from the prior art, the first connecting kidney has a further web which is narrower (seen in the circumferential direction of the access opening) than the first-mentioned web.

In a specific embodiment of the connecting plate according to the invention, the first connecting kidney has one longer perforation and three shorter perforations. Three channels are provided in the first web. The second web is disposed between the shorter first and second perforations. A channel is provided in the second web. The third web is disposed between the shorter second and third perforations. Two channels are provided in the third web.

Of course, more or fewer perforations and webs can be provided.

With all the mentioned designs of the connection plates and the channels, horizontal fluctuations of the load and fluctuations of the two centers of gravity relative to each other can be compensated. The configuration of the lubrication gap becomes more uniform and volume losses and critical contact forces are avoided. Hereby is achieved a reduction of wear and/or an improvement of efficiency or performance of the axial piston machine concerned.

If at least one of the channels is a borehole, it can be made with a drill bit. The radial extension of the passage is then the diameter of the borehole. In this case, it is particularly preferred if a switching hole (ubsteuerbohrun) is provided before the second connecting kidney, as seen in the circumferential direction of the access opening, the diameter of the switching hole corresponding to the diameter of the drilled hole. They can then be manufactured easily in manufacturing technology with the same drill bit.

The diameter of the bore can be between 5% and 80%, particularly preferably between 5% and 20%, of the radial width of the first connecting kidney (and thus its bore).

The hydrostatic axial piston machine of the swash plate structure has a distributor plate, which can also be referred to as a control plate, and which has a circular-arc-shaped first and second connecting kidney. The side lying against the cylinder is connected by means of a first connecting kidney to a first working channel arranged on the opposite side of the distributor plate. The at least first connecting kidney is divided into at least two perforations by at least one web and is therefore designed for high pressure. The webs have cylinder-side flanks that overlap with cylinder-side flanks of the distributor plate, or the webs can easily have the same thickness as the distributor plate in terms of manufacturing technology. According to the invention, the distributor plate is penetrated in the region of the web by a channel, by means of which the side of the distributor plate that is attached to the cylinder is connected to the first working channel. In detail, the lubrication gap between the cylinder and the web of the distributor plate is connected to the first working channel via said channel and is thus acted upon by a pressure medium. Thus, it is possible to reduce or prevent the shortage of the lubricant film formation, such as the necked portion (narrowed lubricant film formation).

In the case of the distributor plate according to the invention and in the case of the axial piston machine according to the invention, it is particularly preferred if the cylinder-side surface of the web coincides with the circumferential annular running surface of the cylinder-side surface of the distributor plate. The cylinder tube rests sealingly against this circumferential annular running surface.

Drawings

An embodiment of an axial piston machine according to the invention and a different distributor plate therefor are shown in the figures.

Wherein:

fig. 1 shows an axial piston machine according to the invention in a longitudinal section;

fig. 2 shows a first embodiment of a distributor plate according to the invention for the axial piston machine of fig. 1;

FIG. 3 shows a second embodiment of a distributor plate according to the invention for the axial piston machine of FIG. 1, and

fig. 4 shows a third embodiment of a distributor plate according to the invention for the axial piston machine of fig. 1.

Detailed Description

Fig. 1 shows a longitudinal section through an axial piston machine 1 according to the invention. The axial piston machine has a housing 2 and a housing cover 4, in which a drive shaft 8 is supported by means of a bearing block (wellla gerung) 6. The drive shaft 8 is connected in a rotationally fixed manner to a cylinder 10, in which cylinder 10 a plurality of pistons 12 are guided in a displaceable manner. These pistons together with the cylinder 10 each define a working chamber 14 which can be connected to a high-pressure channel or a low-pressure channel by means of a respective inlet opening and by means of a distributor plate connected to the housing 2, depending on the rotational position of the cylinder 10. In this case, one of the two channels is located above the drawing plane and the other channel is located below the drawing plane, so that neither channel is shown.

The base-side end sections of the pistons 12 remote from the respective working chambers 14 are each connected to a slide 18 in a ball-and-socket manner. The slide block (Gleitschuh) 18 rests on a sliding surface of a swash plate 20, which is rotatably mounted in the housing 2, so that the pistons 12 execute a piston stroke when the cylinder tube 10 rotates, as a function of the angle of rotation of the swash plate 20. The swash plate 20 is adjusted against the force of the return spring by means of an adjusting device 24.

Fig. 2 shows a perspective view of a distributor plate 16 which can be incorporated as a first embodiment into the axial piston machine of fig. 1. In detail, a plan view of the side 26 lying against the cylinder tube 10 is shown.

The distributor plate 16 has two mutually mirror-symmetrical connecting kidneys 28, 30, each of which has four approximately equally long perforations 32 which are elongate and can also be bent into a kidney shape. Corresponding webs 34, 38 are arranged between the through-holes 32, wherein the web 34 is longer in the circumferential direction 36 (see fig. 1) of the access opening of the working chamber 14 than the other two webs 38.

In each of the longer webs 34 connecting the kidneys 28, 30, two passages 40 are provided in the form of bores 40, the diameter of which in the first exemplary embodiment according to fig. 2 is approximately 50% of the radial width b of the two connecting kidneys 28, 30 (and thus also approximately 50% of the radial width b of the bore 32).

The bores 32 and the channels 40 open into the common plane in the first side 16 shown in fig. 2 into a circumferential annular running surface for the cylinder tube 10.

The long connection plate 34 in question is supplied with pressure medium and thus lubricant via two channels 40 from a high-pressure channel (arranged below the drawing plane of fig. 2).

According to the invention, with different shaping, in particular with different extent of the webs 32, 34 in the circumferential direction 36 and with the additional channels 40, the hydrostatic load-off between the cylinder-side 26 of the distributor plate 16 and the cylinder 10 (see fig. 1) lying against it can also be equalized, so that tilting of the cylinder 10 is reduced or prevented. Thus reducing wear of the axial piston machine involved and improving volumetric efficiency.

Fig. 3 shows a cylinder-side surface 26 of a second embodiment of a distributor plate 16 according to the invention. In such an embodiment, the first connecting kidney 28 is always a high pressure kidney, while the second connecting kidney 30 is always a low pressure kidney. Four webs 38 are provided in the high-pressure kidney 28, which extend approximately equally in the circumferential direction 36.

Two drilled channels 40 are provided in the first web 38 and in the last web 38.

In the second embodiment of fig. 3, the first connecting kidney 28 has four equally long webs 38 (seen in the circumferential direction 36 of the access opening) and five equally long perforations 32. Two channels 40 are arranged in each of the first and last webs 38, one of the two channels 40 being arranged in each case on the radially inner circular-arc-shaped edge of the first connecting kidney 28, and the other of the two channels 40 being arranged on the radially outer circular-arc-shaped edge of the first connecting kidney 28.

Before the low-pressure kidney 30 in the circumferential direction 36, a switching bore 42 is provided, the diameter of which corresponds to the diameter of the drilled channel 40. Thus, these five holes can be made with the same drill bit.

Fig. 4 shows, in the illustration according to fig. 3, a circular contact or circumferential region of a cylinder-side 26 of a third exemplary embodiment of a distributor plate 16 according to the invention. In such an embodiment, the first connecting kidney 28 is also always a high pressure kidney, while the second connecting kidney 30 is always a low pressure kidney. Here, the high pressure kidney 28 is modified relative to the high pressure kidney of the second embodiment of fig. 3.

A longer perforation 44 is provided first along the circumferential direction 36 of the cylinder tube 10 and thus along the circumferential direction of the access opening of the working chamber 14. Behind this, a longer web 34 is provided, in which three channels 40, 46 are provided. All three channels 40 are arranged on the radially outer edge of the high-pressure kidney 28. The middle channel 40 is implemented slightly larger than the other two channels 40. In detail, the intermediate channel 40 has a diameter comparable to the diameter of the other transition hole 46.

Three shorter perforations 32 are arranged behind the longer web 34, with the middle shorter perforation 32 being slightly longer than the other two shorter perforations 32. Two webs 38 arranged between three shorter perforations 32 are embodied as shorter webs 38. One channel is arranged in the first shorter web 38 and two channels 40 are arranged in the second shorter web. The diameter of the channel corresponds to the diameter of the transfer hole 42.

Thus, 8 holes of such an embodiment can be made with two drills.

The perforations of the high-pressure kidney can also be circular, in contrast to the embodiment shown.

A distributor plate for a hydrostatic axial piston machine and a corresponding axial piston machine are disclosed. The high-pressure kidney of the distributor plate has one or more webs, by means of which the high-pressure kidney is divided into two or more likewise kidney-shaped perforations. Since the at least one web coincides on the cylinder side with the contact surface of the distributor plate on the cylinder side, only a minimal lubricating gap is produced between the web and the cylinder, in which lubricating gap a lubricating film forms. In order to avoid constrictions, such as necks, in the lubricating film, the webs are penetrated by one or more channels. Through which passage the pressure medium passes from the high-pressure passage of the axial piston machine through the distributor plate to the lubrication gap as supplemental lubricant.

List of reference numerals

1 axial piston machine

2 shell body

4 housing cover

6 bearing seat

8. Driving shaft

10 cylinder barrel

12 pistons

14 working chamber

16 distribution plate

18 slider

20 sloping cam plate

24 adjusting device

26 side of cylinder

28 first connecting kidney/high pressure kidney

30 second connection kidney/Low pressure kidney

32 perforations/shorter perforations

34 longer connection plate

36 direction of surrounding

38 plate/shorter plate

40 channels

42 conversion holes

44 longer perforations

46 another conversion hole

b radial width

And B radial width.

Claims

1. Distribution plate for a hydrostatic axial piston machine (1) of swash plate construction, wherein the distribution plate has a circular-arc-shaped first and second connecting kidney (28, 30), and wherein at least the first connecting kidney (28) is divided by at least one web (34, 38) into at least two perforations (32, 44), wherein the cylinder-side of the web (34, 38) lies in one plane with the cylinder-side (26) of the distribution plate, characterized in that the distribution plate is penetrated in the region of the web (34, 38) by at least one channel (40), the radial width (B) of which is smaller than the radial width (B) of the first connecting kidney (28), wherein the channel (40) is arranged between the radially inner edge of the first connecting kidney (28) and the radially outer circular-arc-shaped edge, such that the formation of a narrowed lubricating film is reduced or prevented.

2. The distributor plate according to claim 1, wherein the distributor plate is penetrated by a further channel (40) in the region of the webs (34, 38), or wherein the webs (34, 38) are penetrated by a further channel (40).

3. The distributor plate according to claim 2, wherein the two passages (40) are arranged on a common circular arc.

4. A distribution plate according to claim 3, wherein the first connecting kidney (28) has four perforations (32) of equal length, and wherein the two connecting kidneys (28, 30) are mirror images of each other.

5. The distributor plate according to claim 2, wherein one of the two passages (40) is arranged on a radially inner circular arc-shaped edge of the first connecting kidney (28), while the other of the two passages (40) is arranged on a radially outer circular arc-shaped edge of the first connecting kidney (28).

6. The distributor plate according to any of the preceding claims, having a further web (34) longer than the first-mentioned web (38).

7. The distribution plate according to claim 6, wherein the at least one web (34, 38) comprises a first web (34), a second web (38) and a third web, wherein the first connecting kidney (28) has one longer perforation (44) and three shorter perforations (32), and wherein three channels (40) are provided in the first web (34), and wherein a channel (40) is provided in the second web (38) arranged between the first and second shorter perforations (32), and wherein two channels (40) are provided in the third web arranged between the middle and last shorter perforations (32).

8. The distribution plate according to any of the preceding claims 1 to 5, wherein the at least one passage (40) is a bore, and wherein the radial width (B) of the passage (40) is the diameter of the bore.

9. The distributor plate according to claim 8, wherein a transition hole (42, 46) is provided on the second connecting kidney (30), characterized in that the diameter of the drilled hole corresponds to the diameter of the transition hole (42, 46).

10. The distribution plate according to claim 8, wherein the diameter of the bore hole corresponds to between 5% and 20% of the radial width (b) of the first connecting kidney (28).

11. Hydrostatic axial piston machine of swash plate construction with a distributor plate (16), the distributor plate (16) having a circular-arc-shaped first and a second connecting kidney (28, 30), wherein the side (26) of the distributor plate lying against the cylinder (10) is connected by means of the first connecting kidney (28) to a first working channel of the axial piston machine, which is arranged on the opposite second side of the distributor plate (16), and wherein at least the first connecting kidney (28) is divided into at least two perforations by at least one web (34, 38), wherein the side of the cylinder side of the web (34, 38) lies in a plane with the side (26) of the cylinder side of the distributor plate (16), characterized in that the side (26) of the cylinder side is connected by at least one channel (40) to the first working channel in the region of the web (34, 38), wherein the radial width (B) of the channel (40) is smaller than the radial width of the connecting kidney (40) of the first connecting kidney (28) lying between the radial edges of the circular-arc-shaped connecting kidney (28) and the radial edges of the radial edges (28) being prevented.