GB2253660A

GB2253660A - Mechanism comprising a stator,a rotor and a seal interposed between said stato r and rotor

Info

Publication number: GB2253660A
Application number: GB9124812A
Authority: GB
Inventors: Gilles G Lemaire; Marc L Perot
Original assignee: Poclain Hydraulics France SA
Current assignee: Poclain Hydraulics France SA
Priority date: 1990-11-23
Filing date: 1991-11-22
Publication date: 1992-09-16
Anticipated expiration: 2011-11-22
Also published as: CS350291A3; GB9124812D0; GB2253660B; CZ283093B6; BR9105092A; DE4137986A1; FR2669681A1; FR2669681B1

Description

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FIELD OF THE INVENTION

The present invention relates to a mechanism comprising a stator, a rotor and a seal interposed between said stator and rotor.

BACKGROUND OF THE INVENTION

A mechanism such as a motor or a hydraulic pump is known, comprising: a stator, a rotor, which is mounted to rotate with respect to the stator about an axis of rotation, a first of these two elements defining an enclosure containing at least partially the second of the two elements; a seal, which is interposed between said rotor and stator; and a stop for maintaining said seal in axial position; one of the two elements constituted by the stator and the rotor being fixed on an buter body. The purpose of the seal is to insulate the enclosure which contains a fluid under pressure with respect to the outside medium.

According to the known technique, the stop for maintaining the seal is constituted by a shoulder, this shoulder generally being made on a special piece which is fixed on the mechanism, having to be fitted thereon in tight manner.

These known arrangements are cumbersome and result in expensive mechanisms. It is an object of the inven- tion to overcome these drawbacks by eliminating said shoulder from the mechanism.

SUMMARY OF THE INVENTION

To that end, according to the invention, the stop for maintaining the seal is constituted by said outer body.

The following advantageous arrangements are also preferably adopted:

- said outer body presents a plane face which is perpendicular to the axis of rotation and on which said seal is in abutment; - said seal is generally in the form of a U, the base of the U being in abutment on said plane face of the outer body; - the seal presents a rigid reinforcement partially coated in a volume of elastomer, part of said reinforcement extending parallel to the base of the U and presenting a bare face, without coating, which is in abutment on the plane face of the outer body; - the seal comprises a web and two wings which extend substantially perpendicularly to said web, in opposite directions at the ends of the web of the seal, whilst the end of a first of the two wings constitutes a face for abutment of the seal on the plane face of the outer body; - the seal prsents a rigid L-shaped reinforcement, one of the wings of this reinforcement being at least partially coated in a volume of elastomer and constituting said first wing of the seal; - the outer body presents a bearing surface for centering said element of the mechanism fixed on said outer body.

The principal advantage of the arrangements which have just been defined resides in the elimination of the shoulder employed heretofore, which was expensive and cumbersome. Moreover, this relatively fragile piece had a mechanical strength much less than that of the bodv on which the mechanism is mounted. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: Figure 1 is a partial section showing the assembly of a hydraulic motor according to the invention on a receiving structure. 35 Figure 2 is an axial section through a motor according to the invention, representing a first variant of the assembly thereof on the receiving structure.

Figure 3 is an axial section of a motor according to the invention representing a second variant assembly of said motor.

Figure 4 is a section showing detail D of Figure 2; and Figure 5 is a section representing a variant embodiment according to the invention of detail D of Figure 4.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the drawings and firstly to Figure 1, the flange 1 of the case 2 of the motor is fixed by bolts 3 on the chassis 4 of a public works machine, a multi-tyre roller in the example shown, whilst the cylinderblock 5 of this motor is fixed, by screws 6, on a plate 7, itself connected to a vibrating roller 8 via elastic supports 9 made of elastomer.

The detailed constitution of the motor does not form part of the present invention.

In the present case, the motor comprises a case 2, here constituting the stator fixed on the chassis 4, which defines an enclosure 33, with respect to which and inside which the cylinder-block 5, here constituting the rotor, is rotatably mounted, about an axis of rotation 10, by means of conical bearings 11. The cylinderblock 5 comprises a plane transverse end face 12, perpendicular to the axis of rotation 10, on which the plate 7 is in abutment and fixed by screws 6. In addition, cylinder-block 5 comprises a shoulder 13 which comprises two transverse faces 14 and 15, one, 14, oriented towards the interior of the case 2, the other, 15, towards the outside of the case. This shoulder is adjacent the end face 12. The conical bearings 11 are in abutment on the face 14 of the shoulder, whilst a seal 16 is in abutment on the face 15 of the shoulder 13 and on face 7A of plate 7.

The embodiment of Figure 3 is similar to that of Figure 2, completed as follows:

- plate 7 comprises a cylindrical housing 17 defined by a bottom 18 perpendicular to the axis of rotation 10; - the end of the cylinder-block 5 comprises a cylindrical face 19 which is introduced, virtually without clearance, and which is centred in housing 17; - the transverse end face 12 of the cylinder-block 5 is in abutment on the bottom 18 of the housing 17 and is fixed by sirews 6; - seal 16 is still disposed between, and in abutment on face 15 of shoulder 13 and on face 7A of plate 7.

The detail of assembly of seal 16 is illustrated in Figure 4, a variant being shown in Figure 5, these two embodiments each concerning the more general assembly shown in Figure 2.

The embodiment of Figure 4 concerns a seal generally in the form of a U, comprising a rigid, L-shaped reinforcement. One, 20, of the arms of the L extends substantially parallel to face 7A of plate 7, is in abutment on this face 7A, and corresDonds to the base of the U. The other wing 21 of the 1, extends parallel to the axis of rotation 10, i.e. perpendicularly to face 7A, and corresponds to one of the arms of the U. The other arm 22 of the U is made of elastomer, is rendered adherent on the end of the wing 20 of the reinforcement, and comprises two lips 23 which are in abutment on a cylindrical face 2A, opposite, of case 2. Another part 24 made of elastomer is rendered adherent to the wing 21 of the reinforcement and is in sealed abutment on a cylindrical face 5A of the cylinder-block, on face 15 of shoulder 13, and on face 7A of plate 7. An elastic ring 25, made of steel, is disposed on the inner end of arm 22 of the U and contributes to placing one of the lips 23 in abutment on face 2A of case 2.

The embodiment of Figure 5 is that of a seal 16 comprising an L-shaped reinforcement with two wings 26, 27 entirely coated with elastomer. Wing 26 extends substantially parallel to face 7A of plate 7, constitutes the web of the seal and is in abutment, with the interposition of elastomer 28, on face 15 of the shoulder 13. Wing 27 of the reinforcement extends perpendicularly to face 7A of plate 7, is in abutment on the cylindrical face 5A of the cylinder- block 5, with the interposition of elastomer, and its end 27A is in abutment on the face 7A of the plate 7, with the interposition of elastomer. The wing 27 and the elastomer which adheres thereto extend, from the web of the seal constituted by the wing 26 and the adhered elastomer, towards plate 7, whilst an elastomer wing 29 extends substantially perpendicularly to face 7A of plate 7, but in opposite direction to wing 27, from the other end of the web 26 of the seal, i.e. towards the interior of the case 2. This wing 29 comprises two lips 30, which are in abutment on the cylindrical face 2A of the case 2, and which are maintained in abutment by means of a steel ring 32 disposed inside 30the end of the wing 29. A third lip 31 extends from the web 26 towards the cylindrical face 2A on which it is in sealed abutment.

In each of the embodiments of Figures 4 and 5, opposite the shoulder 13, the seal 16 is maintained by and in sealed abutment on the face 7A of the plate 7. Here, this plate 7 is a very resistant plate which advantageously replaces the maintaining shoulder which was used heretofore to maintain the seal.

The use of plate 7 which belongs to the body on which the cylinder-block 5 is fixed, therefore makes it possible, on the one hand, to eliminate a piece, on the other hand, to perform its function with a better efficiency, by reason of the greater resistance of plate 7. The advantage is double: the function of maintaining the seal is better assumed and the means adopted are less expensive than herotoforc.

The advantage of the U-shaped seal of Figure 4 resides in the fact that the pressure of the fluid is exerted inside the U, the reaction being produced on the bearing of the base of the U, therefore directl facing the zone under pressure, hence a minimum deformation of the seal. The face of the seal in abutment on the outer body is not coated to limit the deformations further and to render the position of the lips independent of the pressure.

The advantage of the seal of Figur 5 resides in the fact that, on this seal, the pressure is not exerted opposite the bearing face, so as to obtain a deformation of the seal such that the lips, principally lips 30, are more strongly applied on the surface to be sealed.

The invention is not limited to the embodiments described, but covers, on the contrary, all the variants which may be made thereto without departing from its scope nor spirit.

Claims

WHAT IS CLAIMED IS:

1. In a mechanism, such as a motor or a hydraulic pump, comprising:

- a stator, - a rotor which is mounted to rotate with respect to the stator about an axis of rotation, a first of these two elements defining an enclosure containing at least partially the second of the two elements, - a seal which is interposed between said rotor and stator; and - a stop for axially maintaining said seal in position; one of the two elements constituted by the stator and the rotor being fixed on an outer body; the stop for maintaining the seal is constituted by said outer body.

2. The mechanism of Claim 1, wherein said outer body presents a plane face which is perpendicular to the axis of rotation and on which said seal is in abutment.

3. The mechanism of Claim 2, wherein the seal is generally in the form of a U, the base of the U being in abutment on said plane face of the outer body.

4. The mechanism of Claim 3, wherein the seal presents a rigid reinforcement partially coated in a volume of elastomer, part of said reinforcement extending parallel to the base of the U and presenting a bare face, without coating, which is in abutment on the plane face of the outer body.

5. The mechanism of Claim 2, wherein the seal comprises a web and two wings which extend substantially perpendicularly to said web, in opposite directions at the ends of the web of the seal, whilst the end of a first of the two wings constitutes a face for abutment of the seal on the plane face of the outer body.

6. The mechanism of Claim 5, wherein the seal presents a rigid L-shaped reinforcement, one of the wings of this reinforcement being at least partially coated in a volume of elastomer and constituting said first wing of the seal.

7. The mechanism of any one of Claims 1 to 6, wherein the outer body presents a bearing surface for centering said element of the mechanism fixed on said outer bod,,,.

8. A mechanism comprising a stator, a rotor and a seal, substantially as hereinbefore described with reference to the accompanying drawings.

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