WO2008061768A2

WO2008061768A2 - Bearing shell for a hydrostatic machine and hydrostatic machine comprising said bearing shell

Info

Publication number: WO2008061768A2
Application number: PCT/EP2007/010153
Authority: WO
Inventors: Dino MÜLLER
Original assignee: Robert Bosch Gmbh
Priority date: 2006-11-22
Filing date: 2007-11-22
Publication date: 2008-05-29
Also published as: EP2094980A2; WO2008061768A3; DE102006055161A1

Abstract

The invention relates to a bearing shell (26) for a hydrostatic machine, especially an axial piston machine (1), said bearing shell comprising a fixing element (27a) for fixing the bearing shell (26) that has the shape of an annular sector in the mounting position. In order to improve the bearing shell in terms of a simple construction and assembly or disassembly, the bearing shell (26) consists of a plastic material and the fixing element (27a) is integrally formed thereto.

Description

Bearing shell for a hydrostatic machine and hydrostatic machine with this bearing shell

The invention relates to a bearing shell for a hydrostatic machine or a hydrostatic machine with this bearing shell.

In a hydrostatic machine, in particular an axial piston machine, considerable forces can occur on the individual parts of the machine, in particular on an adjustable drive or shearing disk of an axial piston machine, in particular during operation with high pressure, which leads to wear of these parts, which are just durable should. In this case, even high surface pressures occur, and therefore such bearings are designed to accommodate relatively large loads as plain bearings or roller bearings that can accommodate considerable storage forces. In a sliding bearing this is determined by the relatively large storage or sliding surface. In a roller bearing, the flat pressing is also relatively low, because the bearing rollers rest linearly on the bearing surface.

In an axial piston machine, the pivot bearing of an adjustable swash plate is in particular on the

Pressure side exposed in the pump operation considerable compressive forces to be absorbed by two arranged on both sides of the center axis of the swash plate pivot bearing and be passed to the housing.

In order to be able to realize a large bearing surface, previously known pivot slide bearings or roller bearings kreisbogenabschnittsformig curved bearing shells, which at correspondingly curved abutment surfaces of the housing abutting and convergently open in the direction of the cylinder block.

In order to prevent movement of the bearing shells, in particular in the pivoting direction, it is z. B. from DE 196 13 609 Al, the bearing shells each with a fixing element, e.g. with a threaded screw, thereby ensuring that the threaded bolt engages peg-shaped in a prefabricated hole in the bearing shell.

Such a configuration is complicated and expensive to manufacture, because not only in the housing but also in the respective bearing shell a hole or threaded hole is to prefabricate and the threaded screw after insertion of the bearing shell is to be screwed into its secure position. Another disadvantage is the fact that the existing hole in the bearing cup significantly affects the cross section and thus the strength of the bearing shell.

The invention has for its object to improve a bearing shell and a hydrostatic machine of the type specified in particular with respect. A simple construction and assembly or disassembly. The simplification is to be a simple and inexpensive

Manufacture or assembly or disassembly lead, so that the bearing shell or the axial piston machine is also inexpensive to produce or assemble or disassemble.

This object is solved by the features of claim 1 and 17, respectively. Advantageous developments of the invention are described in the appended subclaims. In both embodiments of the invention according to claim 1 or 17, the bearing shell made of plastic, wherein the fixing element is integrally formed. This can achieve several advantages.

On the one hand, the bearing shell, as a plastic injection-molded part, can not only be produced simply and quickly, and therefore cost-effectively, but also with precision. The latter also makes it possible to prefabricate the bearing shell by injection molding in its final form.

This applies not only to the usual limiting contours of the bearing shell to their support, but also for their at least one bearing surface, which is so smoothly produced by injection molding that it is not only a reworking as a sliding surface but also as a rolling surface for rolling bearing rollers ,

The bearing shell can also be manufactured with a plastic of sufficient hardness, whereby a sufficient wear resistance and durability is achieved.

Another advantage is that plastic has a lower specific gravity than bronze and therefore the bearing shell according to the invention is relatively easy and contributes to weight savings.

It is further advantageous to arrange in the bearing surface of the bearing shell one or more in the direction of curvature successively arranged lubrication recesses, preferably in the feed channel for a

Lubricant, in particular for the hydraulic fluid, opens. This embodiment, which is particularly suitable for a sliding bearing, improves the lubricant supply between the bearing sliding surfaces. The lubrication recesses are preferably formed by lubrication grooves, which at the same time form the feed channels for the lubricant when they open laterally on at least one side of the bearing shell.

The embodiments with lubrication recesses is particularly suitable for the bearing shell, which is located on the pressure side of the axial piston machine.

In the following advantageous embodiments of the invention will be described in more detail with reference to simplified drawings. Show it:

1 shows an axial piston according to the invention in axial section.

2 shows the partial section II-II in Figure 1 in an enlarged view.

Fig. 3 is a visible in Figure 2 bearing shell in plan view.

4 shows the bearing shell in the plan view of Figure 4 in a modified embodiment.

5 shows the bearing shell in section V-V according to FIG. 2 in a further modified embodiment;

6 shows the bearing shell in section V-V according to FIG. 2 in a further modified embodiment;

7 shows the axial piston machine or the bearing shell in a further modified embodiment in a section VV corresponding section. Fig. 8, the bearing shell of FIG. 7 in a perspective view with a view towards their Lagerbzw. sliding surface;

Fig. 9, the axial piston or the bearing shell in a further modified embodiment in a section V-V corresponding section and

Fig. 10, the bearing shell of FIG. 9 in a perspective view with a view towards their Lagerbzw. Sliding surface.

The axial piston machine denoted by 1 in its entirety in Fig. 1 is a hydrostatic machine which, when using a hydraulic fluid, in particular hydraulic oil, can be operated in one or more types of operation, e.g. as a pump or motor, which is well known.

The main parts of the Axialkolbenmaschme 1 are a housing 2, in which a drive shaft 3 in, for example. two, an axial distance from each other having rotary bearings 4, 5 is rotatably mounted and a Durchfuhrungsloch 6 in an end wall 2a of the housing 2 extends outwardly and is rotatably mounted on the end wall 2a in the pivot bearing 4.

The drive shaft 3 is sealed in the region of the end wall 2a by a sealing ring, which is preferably inserted into a ring carrier, which is attached to the end wall 2a.

The housing 2 is preferably a cup-shaped housing, wherein the end wall 2 a forms the bottom of the pot shape, the is detachably closed by a lid 2b, which bears sealed against the free edge of the peripheral wall 2c of the housing 2 and is attached thereto, for example by means arranged distributed on the circumference and indicated by dashed lines fastening screws. 7

In the interior 8 of the housing 2, the following axially successively arranged functional parts of an engine are arranged, namely a drive plate 9 with respect to the longitudinal axis 11 of the axial piston 1 normally obliquely extending drive plane 12, in which a plurality preferably arranged on a pitch circle and in particular approximately Axially extending piston 13 are axially or indirectly supported axially, with their drive disc 9 facing away from the piston shafts 13a in piston holes 14 of a cylinder block 15 axially displaceable, which is rotatably connected to the drive shaft 3 and on its drive plate 9 side facing away axially on a control disc 16 is applied, in their cylinder block 15 facing control surface control openings 17, eg two kidney-shaped and opposing control openings 17, which correspond to extending from the piston holes 14 control channels 18 in the cylinder block 15. To or from the

Control openings 17 extend in the cover 2c each have a supply or discharge line 19, 21 for the hydraulic fluid.

In the embodiment, the drive disk 11 is formed by a swash plate with a cylinder block 15 facing and the drive plane 12 forming oblique sliding surface on which the piston 13 with spherical piston heads 13b and pivotable thereon mounted so-called sliding shoes 22 slidably abut. To ensure the latter during the reciprocating movement of the pistons 13 during functional operation, the piston heads 13b are secured in the sliding position on a sliding surface 9a of the drive plate 9 by means of a retaining device with a sliding disc 22 engaging behind the retaining plate 23. The drive plate 9 is pivotally mounted in a pivot bearing 24 with a transverse to the longitudinal axis 1 extending pivot axis 24a and pivoting to increase or decrease the flow volume of the hydraulic fluid by a pivoting device 25, the pivoting movements are preferably controlled automatically.

In the present embodiment are on both

Side of the drive plate 9 in a Durchfuhrungsloch 9b with movement play comprehensive drive shaft 3 each have a pivot bearing 24b, 24c arranged, which may be the same or with respect to. The longitudinal axis 11 extending longitudinal plane El mirror image formed.

In the present exemplary embodiment, the two pivot bearings 24b, 24c, as shown in Fig. 2, formed by so-called. Schwenkwiegen, i. they each have two sliding or bearing surfaces 2βa, the circular arc or zylinderabschnittformig are curved concavely about the pivot axis 24a, wherein the curvature is open to Zylmderblock 15 out and the drive plate 9 can be mounted from this axial side.

In order to be able to repair the bearing surfaces 2βa in a simple and cost-effective manner in the event of wear, the bearing surface 2βa is in each case attached to a bearing shell 26 formed, which is formed by a corresponding arc of a circle curved bearing strip 26c extending in cross-section preferably parallel to the pivot axis 24a and has a width b, which, taking into account their arcuate length L results in a sufficiently large storage area to achieve the lowest possible surface pressure ,

The length L of the bearing strip 26c extends through an angle W which is less than 180 °, e.g. may be about 110 ° to 150 °.

The bearing shells 26 thus have inside a bearing surface 26a extending at right angles to the radial plane E2 of the concave curvature and externally a contact surface 26d extending parallel thereto, with which they rest against a correspondingly curved contact surface 2e of the housing 2 and are radially supported.

In the above-described embodiment, arranged on both sides of the drive shaft 3 bearing shells 26 each form a plain bearing. But it can also be at least one of the pivot bearings 24b, 24c, for example, arranged on the suction side of the axial piston pivot bearing as rolling bearings with cylindrical or barrel-shaped Wälzrollen Wr be formed, as illustrated in Fig. 2 as a particular detail. In such an embodiment, the Wälzrollen Wr roll on the bearing surface 26a of the bearing shell 26, wherein the radius of the bearing surface 26b on the pivot body is smaller than the radius of the bearing surface 26a. Therefore, between the bearing surfaces 26a, 26b there is a gap in the size of the cross-sectional dimension of the rolling rollers Wr, which are arranged in this gap and roll on the bearing surfaces 26a, 26b in the pivoting mode.

To secure the respective bearing shell 26 against displacement in the circumferential direction is a

Fixing device 27 is provided, which is preferably effective at the same time in the transverse direction. The fixing device 27 has a fixing element 27a arranged on the bearing shell 26 which interacts with a corresponding fixing element 2f on the housing 2 in a form-fitting manner.

In the exemplary embodiment, the fixing element 27a is formed by a protruding from the bearing shell 26 fixing pins, which preferably protrudes from the abutment surface 26d, in particular in a middle position with respect. This, as shown in Fig. 3. The corresponding fixing element 2f is preferably formed by a fixing hole in a cross-sectional shape and size corresponding to the fixing pin, which is preferably arranged in the corresponding bearing surface 2e, preferably also in its middle position.

The Fixierlocher are preferably blind holes, which auseunden on the contact surface 2e.

In such cases, in which it is desired to secure the fixing pin with a clamping voltage in the fixing hole, the existing fit between these parts may be formed as a press fit. In order at such a desired clamping voltage assembly or

To facilitate disassembly, it is advantageous to arrange on the circumference of the fixing pin one or more clamping rings 27b, which are formed diametrically with an oversize and therefore when pressed into the fixing hole yield elastically and press with an elastic clamping voltage against the wall of the fixing hole. The one or more clamping rings 27b are, for example, sawtooth-shaped and facing away from the free end of the fixing pin, whereby they easy insertion into the

Allow fixing hole and cause it to be clamped against withdrawal.

In the sliding surfaces 2βa, according to the embodiment shown in FIG. 4, one or more lubrication recesses 28 are preferably located, into each of which a lubricant supply channel opens. The lubricating recesses 28 are preferably formed by lubrication grooves, which open on at least one side of the bearing shell 26. The lubrication grooves preferably extend obliquely to the associated pivot plane E2, wherein the at least one lateral groove opening 28a is arranged in particular on the end of the associated lubrication groove facing away from the direction of rotation. It is particularly advantageous to allow the lubrication grooves to open out on both sides, so that groove openings 28a are present on both sides. The oblique extent of the lubrication grooves leads to the advantage that the lubricant, preferably the hydraulic fluid, is entrained by frictional contact with the associated bearing surface 26b and thereby conveyed between the bearing surfaces 26a, 26b, whereby the lubrication is improved and the bearing wear is reduced.

Since the loads of the bearing surface 26a or are particularly large on the high pressure side of the axial piston machine 1, it is advantageous to form the lubrication recesses 28 or lubrication grooves in the bearing surface 26a of the bearing shell 26, which is arranged on the pressure side. It but may also be arranged on the suction pressure side bearing shell 26, which has at least one lubrication recess 28.

In the exemplary embodiment according to FIGS. 5 and 6, the bearing shells 26 have on one or both lateral edges a marginal web 26g projecting beyond the bearing surface 26a, the inner surface of which forms a circular-arc-shaped radial shoulder surface 26h which can serve for the associated bearing shell or another part of

Pivot bearings 24, e.g. not shown between the bearing surfaces 26a, 26b arranged roller bearing rollers Wr, laterally limit and thereby secure in the respective pivot plane E2.

With regard to the longitudinal section plane El preferably mirror-inverted bearings 26 are preferably made of a plastic with a hardness and strength, which is sufficiently large, taking into account the surface pressure occurring to accommodate the bearing loads can. It is z. Example, to the known plastic TORLON 4301, in particular to a plastic which is moldable by injection molding into moldings, here the bearing shells 26, in an associated molding device.

Plastic parts produced by injection molding have a so-called spray lug 29 at the point at which the liquid plastic is injected into the mold, and at which forms after the solidification of the plastic, a small approach that interferes in many cases. In the embodiment according to the invention, such a spray attachment 29 may be arranged on the end face of the fixing pin (not shown). One of the Face possibly protruding spray tip 29 may be included in a correspondingly deep-trained fixing hole without disturbing.

In order to avoid larger wall thicknesses in the region of the fixing pin, it is advantageous to design the fixing pin as a hollow pin. In particular, in this embodiment, it is advantageous to spray the sprue 29, e.g. To arrange at the bottom of the cavity 27c of the hollow pin, so that the spray lug 29 projects into the depth of the fixing hole, without having to be made with a large depth.

In the embodiments of FIGS. 7 to 10, in which - as in all embodiments - the same or comparable parts are provided with the same reference numerals, 26 26 a recess 31 are respectively disposed in the bearing surface 2βa or sliding surface of the at least a lubrication recess 28 differs in that its edge 32 has a distance a from the edge 26i of the bearing surface 2βa. As a result, the recess 31 has a closed edge 32 on its entire circumference, and it is closed when the drive disk 9 abuts against the bearing surface 2βa, so that there is no connection to the interior 8 of the housing 2. As FIGS. 7 to 10 clearly show, the recess 31 is located in the middle region of both the length L extending in the direction of curvature and the width b of the bearing shell 26 or its bearing surface 26a extending transversely thereto or parallel to the pivot axis 24a.

The recess 31 may also form a lubricating recess in its training described so far, the the lubrication improved by the fact that the lubricant in the recess 31, preferably the hydraulic fluid, taken by a frictional contact with the bearing surface 26b of the drive plate 9 and thereby between the bearing surfaces 2βa, 26b is promoted or even wetted only. The filling of the recess 31 with the lubricant takes place automatically during operation due to the pressure in the interior 8, which allows the lubricating fluid to seep into the recess 31 due to the sliding clearance existing between the bearing surfaces 26a, 26b.

It is therefore advantageous to arrange the recess 31 in the bearing shell 26, which is located on the pressure side of the axial piston machine 1.

It is particularly advantageous to provide a pressure channel 33, which extends with its one end to the recess 31 and with its other end with the pressure in operation leading discharge channel of

Axial piston machine 1 is connected. As a result, generated during operation of the axial piston 1 in the recess 31 under pressure fluid effective against the drive plate 9 and shown as an arrow unloading force 34, which relieves the drive plate 9 and thus forms a hydrostatic pressure relief. In this case, the area size of the recess 31 is only so great form, that the unloading force 34 is less than an on the drive plate 9 oppositely directed loading force 35, which in operation due to the

Support forces of the piston on the drive plate 9 results.

In the bearing gap 36 between the bearing surfaces 26a, 26b results in the transverse regions a next to the recess 31 a automatically adjusting pressure reduction 37, which is reduced to the housing pressure 38 at the edge 26i of the bearing surface 26a. This is shown in dash-dotted lines by thin auxiliary lines in FIGS. 7 and 9.

The pressure supply to the recess 31 may extend in channels, not shown, through the piston sliding shoes 22 and the drive disk 9 or through the housing 2. In the embodiment according to FIG. 7, a pressure channel 33 extends through the fixing element 27a or the

Fixing pin and the associated Fixierausnehmung and through the bearing shell 26 bearing wall or bottom wall 2a of the housing 2. The connection of the pressure channel 33 with the working pressure contained pressure line of the axial piston machine is not shown for reasons of simplification.

The recess 31 is preferably formed with a plurality of mutually transversely extending and interconnected Nutenabschnitten 31 a, 31 b, between which bearing disk sections 26 k arranged with associated bearing surface portions 26 a, z. B. as a dock or as an island. A groove section 31a extending in the direction of curvature with the length L1 can be provided, from which a plurality of groove sections 31b each having a spacing c extending from each other in the direction of curvature extend transversely or parallel to the pivot axis 24a. In between are the bearing surface sections 26al. Preferably, two mutually extending in the direction of curvature groove portions 31a are provided, which have a distance x from each other, wherein the transverse thereto extending groove portions 31b with two groove portions 31a are connected. The groove portions 31b may extend obliquely.

The depth t of the recess 31 may be low and z. B. only about 1 mm or more.

In the area of located on the suction side of the axial piston machine 1 bearing shell 26 shown in FIG. 9 and 10, because of the lower load during operation, the recess 31 only needs to be formed as a lubrication recess, d. H. the pressure channel 33 need not be present, as shown in FIG. 9. In addition, the length Ll of the recess 31 may be less than in the bearing shell 26 of FIG. 7 and 8 on the pressure side. It is within the scope of the invention, however, also possible in the

Bearing shell 26, which is located on the suction side, no recess 31 or no lubrication recesses 28 to be arranged.

The invention is not limited to those shown

Embodiments limited. In the context of the invention, a further simplification can be achieved in that the two bearing shells 26 are of the same design, whereby they fit into positions rotated through 180 ° and therefore only one type of bearing shell 26 needs to be manufactured and stored or even distributed, around a pivot bearing 24 to realize with two bearings 26 according to the present embodiment. All described and / or drawn features can be combined with each other in the context of the invention.

Claims

claims

1. bearing shell (26) for a hydrostatic machine, in particular an axial piston machine (1), with a fixing element (27a) for fixing the circular arc segment-shaped curved bearing shell (26) in the installation position, wherein the bearing shell (26) consists of plastic and that fixing element ( 27a) is integrally formed.

2. Bearing shell according to claim 1, characterized in that the fixing element (27a) by one of the bearing shell (26), in particular of its axis of curvature (24a) facing away from abutment surface (26d), protruding fixing pins is formed.

3. Bearing shell according to claim 2, characterized in that the fixing pin at its periphery clamping ribs (27 b).

4. Bearing shell according to one of the preceding claims, characterized in that it comprises in its sliding surface (26a) one or more in the direction of curvature successively arranged lubricating recesses (28), preferably in each case a supply channel for supplying a lubricant, in particular the hydraulic fluid, flows out.

5. Bearing shell according to claim 4, characterized in that in that the at least one lubrication recess (28) is formed by a lubrication groove which opens out on one or both sides of the bearing shell (26) and preferably extends obliquely to the plane of curvature (E2) of the bearing shell (26).

6. Bearing shell according to one of the preceding claims, characterized in that the bearing shell (26) in its bearing surface (26 a) or sliding surface has a recess (31), the edge (32) a distance (a) from the edge (26 i) Storage area (26a).

7. Bearing shell according to claim 6, characterized in that the recess (31) in the central longitudinal region (L) and in the middle width region (b) of the bearing surface (26 a) is arranged.

8. Bearing shell according to claim 6 or 7, characterized in that the recess (31) consists of a plurality of transversely extending and interconnected Nutenabschnitten (31a, 31b) is formed, between which bearing shell sections (26i) with bearing surface portions (26al) are arranged ,

9. bearing shell according to claim 8, characterized in that the recess (31) by a extending in the direction of curvature groove portion (31 a) is formed, from which a plurality of transverse groove portions (31 b) extend.

10. Bearing shell according to claim 9, characterized in that the transverse groove portions (31b) are connected to a second extending in the direction of curvature groove portions (31a).

11. Bearing shell according to claim 9 or 10, characterized in that the transverse groove portions (31b) extend obliquely.

12. Bearing shell according to one of claims 6 to 11, characterized in that a channel (33) for a pressurized fluid to the recess (31) which preferably extends through the fixing element (27 a).

13. Bearing shell according to one of the preceding claims 2 to 12, characterized in that the fixing pin is a hollow pin.

14. Bearing shell according to one of the preceding claims 2 to 13, characterized in that a spray attachment (29) of the bearing shell (26) in the region of the end face of the fixing pin, in particular in a cavity of the hollow pin, is arranged.

15. Bearing shell according to one of the preceding claims, characterized in that it has on one or both sides of its bearing surface (26 a) superior edge web (26 g).

16. Bearing shell according to one of the preceding claims, characterized in that it consists of the plastic TORLON 4301.

17. Hydrostatic machine, in particular

Axial piston machine (1), with a housing (2), in which a drive disc (9) in a pivot bearing (24) about a transverse pivot axis (24a) is pivotally mounted, wherein with respect to the drive plate (9) axially displaced a cylinder block (15 ) is mounted in the housing (2) having distributed on a circumference piston holes (9) in which pistons (13) are slidably mounted, the piston heads (13b) are pivotally supported on the drive disc (9), and wherein on both sides a drive disk (9) in a through hole (6) with movement play and in the housing (2) rotatably mounted drive shaft (3) each having a pivot bearing (24a, 24b) is arranged, which has a circular arc section bearing surface (26a) on the Inside a circular arc curved curved bearing shell (26), characterized in that the pivot bearing (24) has a bearing shell (26) according to one of the features of the preceding claims.

A hydrostatic machine according to claim 17, characterized in that one or both bearing shells (26) form a sliding bearing and / or rolling bearing, e.g. the rolling bearing on the suction side of the axial piston machine (1) is arranged.

19. Hydrostatic machine according to claim 17 or 18, characterized that both or only one bearing shell (26), in particular the bearing shell (26) arranged on the pressure side of the axial piston machine (1), has one or more lubrication recesses (28) arranged one behind the other in the direction of curvature.

20. A hydrostatic machine according to claim 19, characterized in that at least one lubrication recess (28) is formed by a lubrication groove on one or both

Side of the bearing shell (26) opens and preferably obliquely with respect to the pivoting plane (E2).

21. Hydrostatic machine according to one of the preceding claims 17 to 20, characterized in that both or only one bearing shell (26), in particular on the pressure side of the axial piston machine (1) arranged bearing shell (26), a recess (31) according to the claims 6 to 12 in its bearing surface (26 a).

22. A hydrostatic machine according to claim 21, characterized in that also the bearing shell (26) on the suction side of the axial piston machine (1) has a recess (31), wherein the length (Ll) of this recess (31) is preferably less than the Length (Ll) of the recess (31) in the arranged on the pressure side bearing shell (26).