GB2152594A

GB2152594A - Radial piston machine

Info

Publication number: GB2152594A
Application number: GB08431318A
Authority: GB
Inventors: Klaus Griese; Siegfried Mayer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1984-01-12
Filing date: 1984-12-12
Publication date: 1985-08-07
Also published as: DK162790B; DK162790C; DE3400867A1; DE3400867C2; JPS60159380A; GB8431318D0; DK15185A; GB2152594B; DK15185D0

Abstract

The radial piston machine has a cylinder body (6), which rotates on a control spigot (5) fixed to the housing. Several, radially running bores (7) are made in the cylinder body, in which bores (7) pistons (8) slide which are supported on the guide surface of a displacement ring (11) by means of sliding shoes (9). The sliding shoes are kept in constant contact with the guide surface by means of retaining rings (12, 13). Passages (22) are designed on the outer periphery of the retaining rings, by means of which passages (22) the area at the sliding shoe base is in contact with the inside of the machine, for example via longitudinal grooves (24; 25), which are located in the side surfaces facing towards the cylinder body. In this way, dirt particles, which are located in the area of the sliding shoes, are flushed by the pressure medium into the inside of the machine where they are separated in a filter on their way to the container. An alternative ring has a polygonal outer surface. <IMAGE>

Description

SPECIFICATION Radial piston machine Prior state of the art The invention is based on a radial piston machine according to the generic type of the main claim. In such known radial piston machines, the retaining rings, at their outer periphery are completely in contact with the inner side of the displacement ring, so that no pressure medium can escape via the outer periphery into the inside of the machine. This has the disadvantage that dirt particles, which have entered into the pressure medium by abrasion, cannot be flushed out, or can only be flushed out with difficulty, so that there is the risk of the sliding shoes being scored.

Advantages of the invention In contrast, the radial piston machine according to the invention and having the characterising features of the main claim has the advantage that the pressure medium and dirt particles contained in the latter can enter via the passages into the inside of the housing and from there into the container, where they are filtered out during the next suction stroke.

This considerably reduces the failure rate quota of the machines.

On account of the measures listed in the sub-claims, advantageous further developments and improvements of the features stated in the main claim are possible. These consist of particularly expediently designed passages which, for example, can be manufactured by form tools.

Drawing An illustrative embodiment of the invention is shown in the drawing and is explained in greater detail in the following description. Fig.

1 shows a longitudinal section through a radial piston pump, Fig. 2 shows an elevation of a retaining ring, Fig. 3 shows a section along Ill-Ill according to Fig. 2 and Fig. 4 shows a modified retaining ring.

Detailed description The radial piston pump has a roughly cuplike housing 1, which is closed by a housing cover 2. A bore 3 emerges from the housing end face remoate from the housing cover 2, which bore 3 leads into an approximately oval recess 4, which forms a section of the inside of the housing. A control spigot 5 is pressed into the bore 3, which control spigot 5 protrudes with a longitudinal section into the recess 4. In the recess 4 is arranged a cylinder body 6 which, by means of a bore 6', is rotatably mounted on the control spigot and accomodates pistons 8 in radially running bores 7, which pistons 8 are supported by means of sliding shoes 9 on a guide surface 10 of a displacement ring 11.If the machine is designed to be adjustable, the displacement ring 11, in the recess 4, is adjustably arranged for changing the piston stroke, although this is not shown in connection with the invention. On both sides of the sliding shoe base are located retaining rings 12, 1 3 which have the task of keeping the sliding shoe continually in contact with the guide surface 10 of the displacement ring. For this purpose, a projecting ring edge 12', 13' of the retaining ring grips slightly over the base of the sliding shoe.

Segment-like projections 21 are designed at regular intervals on the outer periphery of the retaining ring 12, so that axial passages 22 are produced between these projections 21.

The projections 21 are then, at their outer periphery, in contact with the guide surface of the displacement ring. The displacement ring 1 3 is designed in exactly the same way.

Several narrow, longitudinal grooves 24 are designed on the housing side facing towards the cylinder body and the retaining ring 12, which longitudinal grooves 24 extend as far as the control spigot 5 and consequently into the inside of the housing. On the cover 2, too, are designed several-but now substantially shorter-longitudinal grooves 25 on the cover inner side facing towards the cylinder body, which longitudinal grooves 25 also lead into the inside of the housing. Consequently there is a pressure medium connection from the sliding shoe via the retaining rings to the inside of the housing, so that dirt particles, which are located in the area of the sliding shoes, are flushed into the inside of the housing. From there they enter into the container and are caught in the filter.This ensures that dirt particles scarcely reach the base of the sliding shoe, so that scoring at the sliding shoe does not occur, and consequently the life of the machine, in part, can be substantially improved.

Two diametrically opposite control openings 14, 1 5 are made on the control spigot 5, which control openings 14, 1 5 interact with the orifices of the cylinder bores 7 and .

(sic) each of which a channel 1 6, 1 7 leads, which runs partly in the housing 1 and partly in the control spigot, for the supply or discharge of the pressure medium. The two control openings 14, 1 5 are separated from one another by transverse webs 18, 1 9. An annular groove 20 is designed in the control spigot 5, which annular groove 20, when the control spigot 5 is pressed into the bore 3, is located where the bore 3 merges into the recess 4: the longitudinal groove 16 also opens out here.

Fig. 4 shows a variant of the retaining rings. This retaining ringdesignated by 23-has a polygonal profile on its outer side.

This also produces a larger number of passages along the guide surface of the displacement ring.

Claims

1. Radial piston machine with a cylinder body mounted on a control spigot, which cylinder body has approximately radially arranged bores in which delivery pistons are arranged in a sliding manner, which are supported by means of sliding shoes (9) moving on the inner side (guide surface) of a displacement ring, which sliding shoes (9) are held in their position by means of at least one retaining ring (1 2, 1 3), which is arranged at the side of the sliding shoes and, at its outer periphery, is also in contact with the inner side of the displacement ring (1 1), characterised in that, on the outer periphery of the retaining ring (1 2, 1 3), are provided several passages (22) running in the axial direction, by which means connection is made to the inner space of the machine.

2. Machine according to Claim 1, characterised in that the passages are formed by segments (21) located on the outer periphery of the displacement ring.

3. Machine according to Claim 1, characterised in that the retaining ring (23) is designed as a polygon on the outer periphery.

4. Machine according to one of Claims 1 to 3, characterised in that radial grooves (24) are designed on the end face of the retaining ring, which grooves (24) lead to the passages.

5. Machine according to one of Claims 1 to 4, characterised in that a retaining ring is arranged on each side of the sliding shoe (9).

6. Machine according to one of Claims 1 to 5, characterised in that longitudinal grooves (16, 1 7) are designed on the housing sides facing towards the cylinder body, which longitudinal grooves (16, 17) lead from the passages (22) to the inside of the machine.

7. Machine according to one of Claims 1 to 6, characterised in that the retaining rings are made of a plastic, especially polyamide.

8. A radial piston machine substantially as herein described with reference to Figs. 1 to 3 or Fig. 1 as modified by Fig. 4.