GB2283541A

GB2283541A - Radial piston machine

Info

Publication number: GB2283541A
Application number: GB9422133A
Authority: GB
Inventors: Sinclair Cunningham; Peter Wuesthof
Original assignee: Mannesmann Rexroth AG
Current assignee: Bosch Rexroth AG
Priority date: 1993-11-03
Filing date: 1994-11-02
Publication date: 1995-05-10
Also published as: FR2712033B1; DE4337508A1; GB9422133D0; FR2712033A1

Description

1 Radial Piston Machine 2283541 The present invention relates generally to

a hydraulic piston machine and in particular to a radial piston motor which is preferably designed as a "plug-in" motor, i. e. a motor which can be readily inserted into annother apparatus.

Hydraulic radial piston motors are known and are frequently used as drive means for different applications. For example, Fig. 1 discloses a prior art radial piston machine having a housing within which a rotor is rotatably mounted which is connected to a shaft. Pressure medium is supplied via a commutator at one side of the rotor. At the opposite side of the rotor, i.e. at the side from which the shaft extends, two adjacently located anti-friction bearings are provided. The use of such bearings is relatively expensive and also the known designs require relatively much space.

It is an object of the present invention to overcome the disadvantages of the prior art. Specifically, the hydraulic machine as set forth in the preamble of claim 1 should be designed such that the radial piston machine, specifically in the form of a radial piston motor, is compact and can be built at low cost. The radial piston motor of the invention should be particularly suitable for use in a drive or gear means.

To provide a solution to the above defined problem, the invention provides for a radial piston machine - particularly a motor - as set forth in the preamble of claim 1 and which is characterized by the features of the characterizing clause of claim 1.

2 A control means housing or casing is provided which is adapted for direct communication with the rotor. The control means housing is a compact component which can be mechanically coupled to the housing or casing of the machine. A compensation means or plate is used for sealingly press the rotor against the control means housing.

Preferably, the radial piston motor of the invention has the compensation plate on the shaft side of the rotor and the control means housing is located oppositely to said shaft side on the other side of the rotor. Due to the teachings of the invention, preferably, the shaft can be provided without bearing means, with the exception of a guide bearing means.

The control means housing can be of a relatively small size, so as to save on cost. This is so, because the control means housing needs to provide only for the necessary opening means or bores required for commutation. Inasmuch as the control means housing does not need to carry out any movements, it can be mechanically connected to the housing of the machine by means of screws or bolts. It is also possible to cast the control means housing together with the housing of the machine, specifically a part of the housing of the machine as a single piece. The compensation plate of the invention makes it unnecessary to use expensive anti- friction bearings.

The radial piston motor of the invention is particularly useful for drive systems, where the motor is used by itself as a torque generating component or section. An example is the use of the radial piston motor of the invention for a gear box. Preferably, a radial piston 3 motor of the invention can be used as a drive means for a concrete mixing apparatus.

Additional advantages, objects and details of the invention will follow from a description of an embodiment of the invention as well as from a description of the prior art.

Fig. 3 Fig. 4 Fig. 5 The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which:

Fig. 1 is an axial section through a radial piston engine of the prior art;

Fig. 2 is a schematic axial section through a radial piston machine, in particular a radial piston motor, of the invention; is a schematic side elevational view of the machine of Fig. 2 from the right-hand side; is an axial section similar Fig. 2; is a detail of Fig. 4; Fig. 6 is a sectional view of the control means housing 80; Fig. 7 Fig. 8 is an enlarged representation of the left part of Fig. 4; is an enlargement of the representation of Fig. 5.

Fig. 1 discloses a hydraulic radial piston machine 100 of the prior art. Said machine 100 comprises a first housing

4 half 1 and a second housing half 2. A cam ring 3 is located between said two housing halves 1, 2 and bolts 4 are used for connecting said three mentioned components 1, 2,, 3. A shaft 5 is rotatably supported within the housing 1, 2 of the machine 100 by means of bearings 6 and 7. The shaft supports at its shaft end 8 adjacent to a recess 9 a rotor 10. A plurality of piston chambers 11 is provided within the rotor in a radially extending manner. The chambers 11 are adapted to receive a like number of pistons 12. The pistons 12 are supported by the inner surface of the cam ring 3 by means of cylindrical rollers.

is Within the second housing half 2 a control sleeve 24 is axially movably supported. The control sleeve 24 is provided with control bores 22, 23 which are connected to ports in a manner not shown in detail but wellknown in the art. Said control bores 22, 23 are adapted to supply or remove pressure fluid or pressure medium via axially extending bores 21 depending upon the position of the rotor 10. The control chambers 25 and 26 are connected with the just mentioned ports.

Figs. 2 through 8 disclose an embodiment of a hydraulic radial piston machine 200 in accordance with the invention. Preferably, the radial piston machine 200 is designed as a radial piston motor. The machine housing of the machine 200 comprises a first housing half and a second housing-half 52. Between said two housing halves 51, 52 a cam ring 53 is arranged.Said three components 51, 52 and 53 are held together by means of bolts which extend through bores 54 in the cam ring 53. Within the machine housing 51, 52 and the cam ring 53 a rotor 60 is rotatably mounted. In a plurality of radially extending piston chambers 67 of the rotor 60 pistons 68 are reciprocally mounted. The pistons 68 are supported via rollers 69 at the inner surface of the cam ring 53. In an opening 79 of the second housing half 52 adjacent to the end of the shaft 55 a control means housing 80 is fixedly mounted by means of screw bolts 83. It is conceivable to design the control means housing 80 as a single piece with the second housing half 52. For instance, the control means housing 80 could be cast together with the housing half 52 as a single piece.

The control means housing 80 is provided, in a manner known,with ports 84 and 85 for supplying and removing pressure medium, preferably a liquid, like hydraulic oil. Channels 86, 87, 88 are provided in the control means housing 88 and are used to supply to and to remove from the piston chambers67 pressure medium via control bores 22, 23 depending upon the position of the rotor 60 with respect to the control bores 22, 23 and with respect to the bores 21 provided in the rotor 60.

On the other side of the rotor 60 opposite to the control means housing 80 compensation means are provided. The compensation means is provided in the form of a compensation plate 82. The compensation plate 82 can be said to be located on the shaft side of the machine (or motor) 200 or of the rotor 60, i.e. the side from which the shaft 55 extends outwardly. The compensation plate 82 is located in a recess 76 of the housing half 51. Preferably, the recess 76 is of a step- like design. As is shown, there are preferably three steps provided. Annular sealing means 62, 63 and 64 are located in said steps.

The compensation plate 82, in turn, comprises a correspondingly step-like outer circumference or face, facing away from the rotor 60. Thus, as is shown, the compensation plate 82 is placed with its respective steps on the respective steps of the recess 76, such that a sealing engagement occurs with the seals 62, 63 and 64.

6 opposite said step-like face the plate 82 has annular face for engagement with the left rotor side face.

The compensation plate 82 is provided at its rotor side end, i.e. the right end in Fig. 2 with a projection 92.

The projection 92 extends inwardly and forms an abutment for a spring 90. The spring 90 is further in abutment with another projection, i.e. a radial projection 56 provided at the housing half 51. Spring 90 urges the compensation plate 82 against the (left in Fig. 2) side surface of the rotor 60, as is shown for instance in Fig.

2. This urging or biasing is necessary for a situation where no pressure of the pressure fluid or medium exists.

In operation, after a pressure of the pressure medium has built up, the compensation plate 82 is pressed or urged against the respective side surface of the rotor 60 due to the effect of said pressure of the pressure medium.

For this purpose, pressure medium is supplied via channels 97 and 98 which lead to the pressure chambers 93 and 94. Said pressure chambers 93 and 94 are formed between preferably radially extending side surfaces of the housing half 51 and the compensation plate 82.

The supply of pressure medium to the channels 92 and 98 occurs via at least two borgs 65 and 66 in rotor 60. Said bores 65 and 66 are connected to piston chambers 67 which are differently subjected to the pressure of the pressure medium and the connection is such that the required pressure is always present in at least one of said chambers 94, 95 for urging the compensation plate 82 against the (left) side surface of the rotor 60.

Due to the fact that at least two pairs of pistons 68 and piston chambers 67 are provided which are out of phase by 90 hydraulic degrees, and due to the fact that two bores 65, 66 are connected with the one or the other pair, it is guaranteed that either the inlet pressure or the 7 return pressure can be used for urging the compensation plate 82 against the rotor 60.

In accordance with the present invention, the shaft 55 is for all practical purposes supported without bearing means. only a guide bearing 30 is provided preferably at the end of the shaft 55. The guide bearings 30 is preferably located in a recess of the ontrol means housing 80 which forms a bearing surface 32.

Specifically Figs. 4, 5, 6, 7 and 8 disclose additional details of the invention supplementing Figs. 2 and 3. Fig. 7 discloses in some detail channels 98 which can be referred to as pressure supply openings. Said channels 98 are preferably provided for two piston bores 67. In the bottom portion of Fig. 7 the inner pressure supply openings can be recognized which are again preferably provided for two piston bores in a sense as was described above. Fig. 7 further discloses the chambers 93 and 94 in more detail which form, so to speak, inner and outer balancing surfaces.

The detail of Fig. 8 discloses the arrangement of a balancing pressure relief groove 40. Groove 40 is connected via an axially extending channel 42 with a radially extending chamber 43. Channel 43, in turn, ends between the left rotor side wall and the housing half 51.

The invention is not limited to the embodiments described, but on the contrary covers all the variants that may be made thereto without departing from the scope or spirit therof.

8

Claims

c 1 a i m 5

A radial piston machine, in particular a radial piston motor comprising machine housing (51, 52), cam ring (53), rotor (60) rotatably mounted in said housing (51, 52), a shaft (55) connected for rotation with said rotor (60), a plurality of pistons (68) reciprocally mounted in said rotor (60) and adapted to cooperate preferably via rollers (60) with said can ring, and commutator means adapted to supply and remove pressure medium to and from said rotor, characterized in that on the one side of said rotor (60) a control means housing (80) is provided, and that on the other opposite side of the rotor compensation means (82) are provided.
2. The radial piston machine of claim 1, wherein said control means housing (80) is in direct communication with said rotor (60) and is stationarily or fixedly mounted to the machine housing (51, 52).
3. The radial piston machine as set forth in one or more of the preceding claims, wherein the control means housing (80) and the machine housing (51, 52) are cast as a single piece.
4. The radial piston machine as set forth in one or more of the preceding claims, wherein the machine housing comprises two housing halves (51, 52) and 9 wherein the control housing means (80) is provided at one of said housing halves.
5. The radial piston machine as set forth in one or more of the preceding claims, wherein said compensation means comprises a compensation plate which is arranged in an axially movable manner.
6. The radial piston machine of claim 5, wherein the compensation plate (82) is biased by means of a spring (90).
7. The radial piston machine of claim 1, wherein said compensation means is a compensation plate which is biased by a spring, wherein further means are provided to urge said compensation plate by means of pressure against one side surface of said rotor (60).
8. The radial piston machine as set forth in one or more of the preceding claims, wherein the compensation plate (82) is of step-like design at its outer circumference and is located in a housing half (51) which is provided at its inner circumference with a corresponding, likewise step like design.
9. The radial piston machine of one or more of the preceding claims, wherein pressure supply means are provided so as to supply the compensation plate (82) with pressure fluid.
10. The radial piston machine of one or more of the preceding claims, wherein the rotor (60) comprises at least two bores (65, 66) which are adapted to supply pressure medium so as to cause the engagement of the compensation plate with the side surface of the rotor (60).
11. The radial piston machine of claim lo, wherein said bores (65. 66) end on the one-hand side in annularly extending grooves (95, 96) in the face of the compensation plate (82) facing towards the rotor, and wherein said bores (65, 66) end on the other hand side in at least two different chambers (67).
12. The radial piston machine of one or more of the preceding claims, wherein a spring (90) is provided which biases the compensation plate (82) against a side surface of the rotor (60).
13. The radial piston machine of one or more of the preceding claims, wherein the shaft (55) is arranged, for all practical purposes, without a bearing in the machine housing, and wherein further preferably only a guide bearing (30) is provided which is arranged in or on the shaft (55), preferably within a recess of the control means housing (80).