EP0603356A1

EP0603356A1 - Advanced rotary hydraulic valve

Info

Publication number: EP0603356A1
Application number: EP93912892A
Authority: EP
Inventors: Guasch Esteve Cortes
Original assignee: AlliedSignal Automotive Espana SA; Bendix Espana SA
Current assignee: AlliedSignal Automotive Espana SA
Priority date: 1992-07-10
Filing date: 1993-06-04
Publication date: 1994-06-29
Also published as: JPH06510259A; WO1994001316A1

Abstract

Distributeur hydraulique comprenant un rotor (1) et un stator (2) dans lesquels sont définies des chambres de pression correspondantes (11, 21; 12, 22; 13, 23). Les paires voisines de chambres correspondantes sont rendues étanches l'une par rapport à l'autres au moyen d'un organe presseur (5) et d'un joint déformable correspondant (4a) logés à la périphérie d'une des chambres de pression du rotor.Hydraulic distributor comprising a rotor (1) and a stator (2) in which corresponding pressure chambers (11, 21; 12, 22; 13, 23) are defined. The neighboring pairs of corresponding chambers are made sealed with respect to each other by means of a pressing member (5) and a corresponding deformable seal (4a) housed at the periphery of one of the pressure chambers of the rotor.

Description

IMPROVED ROTARY HYDRAULIC VALVE

The present invention relates to a rotary hydraulic distributor comprising first and second distribution members capable of undergoing relative rotation, and sealing means, the first distribution member adopting an at least partially cylindrical shape with axial symmetry and adjusting rotationally inside a bore of complementary shape of the second distribution member, each of the first and second distribution members comprising at least first and second pressure chambers spaced apart from one another in an axial direction and subjected to respective pressures, the difference of which is variable, each chamber of each dispensing member being capable of being located opposite the corresponding chamber of the other dispensing member to be subjected to the same pressure as it, and the means sealing comprising: a peripheral annular groove made in the first distri bution, a deformable annular seal insulating from each other, in an axial direction, the first and second pressure chambers, and an annular pressing member bearing on the internal surface of said bore to press the deformable seal inside the throat.

Distributors of this type are capable of receiving various applications but are in particular used, in a known manner, in power steering systems for motor vehicles, as shown for example by US Patents 4,527,591 and EP 0 112 201.

The problems encountered in the production of such dispensers or in their operation are multiple.

First of all, these distributors are of relatively large structural complexity, therefore of relatively high manufacturing cost, and it would be desirable to be able to simplify them and reduce the manufacturing cost.

Furthermore, since the technique permanently requires the addition, to existing devices, of new functions in a constant or possibly reduced volume, current hydraulic distributors have a space requirement which it would be advisable to reduce.

Finally, when the first and second pressure chambers of a current hydraulic distributor are subjected to respective pressures the difference of which varies, there appears a specific sealing problem, which is linked to the displacement of the joint supposed to isolate the second chambers from the first, which manifests itself by consumption of the fluid whose circulation is controlled by the distributor, and which would also be desirable to eliminate.

In this context, the aim of the present invention is to solve at least one of the problems previously mentioned.

To this end, the dispenser of the invention is essentially characterized in that the annular groove which receives the deformable seal communicates with the second pressure chamber of the first dispensing member, forms the periphery of this chamber and adopts a substantially rectangular section, in that the pressing member maintains the deformable seal against the bottom of this annular groove while pressing it against that of the internal lateral walls of this groove which is closest to the first pressure chambers and in that the pressing member is pierced with a bore opposite the second pressure chamber of the second dispensing member.

According to a conventional arrangement in itself, the deformable seal is for example a toroidal seal with a circular section at rest.

In the case where the distributor is such that the first and second distribution members each comprise a third pressure chamber arranged, in an axial direction, on the side of the second chamber which is opposite to that where the first chamber is located, this distributor preferably comprises a second deformable seal insulating the second and third pressure chambers and, the pressing member housed in the annular groove at the periphery of the second pressure chamber of the first distribution member ensures the maintenance of this second seal in an equivalent manner to the one for which he maintains the first joint.

For example, the pressing member then has two chamfers by which it presses the two deformable seals against the two respective circular edges that form the bottom of the annular groove at the periphery of the second pressure chamber of the first distribution member and the two internal side walls of this groove.

Other characteristics and advantages of the invention will emerge clearly from the description which is given below, for information and in no way limitative, with reference to the appended drawing, in which: - Figure 1 is a partial longitudinal sectional view of a typical dispenser of the prior art;

- Figure 2 is a partial longitudinal sectional view of a dispenser according to a first embodiment of the invention; and

- Figure 3 is a partial longitudinal sectional view of a dispenser according to a second embodiment of the invention.

The same reference numbers will be used in the three figures to designate identical or easily comparable elements.

The hydraulic distributors of the type concerned comprise a first distribution member, for example a metal rotor 1, and a second distribution member, for example a metal stator 2.

The rotor 1 adopts at least partially the shape of a cylinder of revolution of longitudinal axis 3 shown, for the purposes of the drawing, much closer to the stator 2 than it actually is.

The rotor 1 adjusts in rotation inside a cylindrical bore 2a of the stator 2, centered on Tax 3 which also constitutes the axis of rotation of the rotor 1.

The rotor 1 and the stator 2 each comprise at least two pressure chambers, such as 11, 12, 13 and 21, 22, 23, each chamber consisting of any cavity such as groove or channel.

On the rotor on the one hand, and on the stator on the other, the various chambers are spaced from each other in the longitudinal direction defined by the axis 3, and each of the first, second and third chambers 11, 12 and 13 of the rotor 1 is likely to be located or to be placed opposite the corresponding chamber 21, 22 and 23 of the stator 2 so that the chambers of each pair of corresponding chambers are subjected to the same pressure.

However, since the pressure prevailing in a pair of corresponding chambers, such as 11 and 21, must be able to differ from the pressure prevailing in the neighboring pair of corresponding chambers, such as 12 and 22, and where this difference is itself even generally variable, it should be made as tight as possible, one by relative to each other, the neighboring pairs of corresponding chambers.

This is achieved in the prior art (Figure 1) by providing, between the neighboring pairs of corresponding chambers, a peripheral annular groove such as 1a, 1b, formed in the rotor 1, a deformable annular seal such as 4a, 4b, and an annular pressing member such as 5a, 5b, bearing on the internal surface of the bore 2a of the stator 2 to press the deformable seal at the bottom of the annular groove.

Preferably, the deformable seal is an O-ring made of an elasto era and the pressing member 5a, 5b, is made of a material with little deformability and having a low coefficient of friction, and for example PTFE ("TEFLON") .

In the prior art hydraulic distributors produced in accordance with FIG. 1, and taking into account that the seals and pressing members such as 4a, 5a cannot fill the entire internal volume of the grooves such as the due to the tolerances of manufacturing, a variation of the pressure difference between two neighboring chambers such as 21 and 22, in communication with the corresponding chambers 11 and 12, leads to a movement of the seal 4a, and / or of the pressing member 5a and to a loss of fluid in that of the two neighboring pairs of corresponding chambers which, at the time of this loss, are at the highest pressure.

This problem is solved, in accordance with the invention, by the arrangements illustrated in Figures 2 and 3.

In a distributor according to the invention, the annular groove communicates it with the second pressure chamber 12 of the rotor 1, forms the periphery of this chamber, that is to say extends in the part thereof which is furthest from the axis 3, and adopts, in the plane which contains Tax 3, a substantially rectangular section, the housing offered by this groove therefore comprising a bottom 12a and two internal side walls 12b and 12c.

Furthermore, the pressing member 5 maintains the deformable seal 4a against the bottom 12a of the groove while pressing it against the internal lateral wall 12b which is closest to the first pressure chambers 11 and 21.

Finally, the pressing member 5 is pierced with a bore 50 facing the second pressure chamber 22 of the stator 2, so as to be able to make communicate this chamber with the second pressure chamber 12 of the rotor 1.

In the case where the rotor and the stator of the distributor each comprise a third chamber 13, 23, the invention can be implemented in accordance with the embodiment illustrated in FIG. 3.

In this case, the pressing member 5 can compress a second deformable seal 4b disposed, relative to the third and second pressure chambers, as Test the first seal 4a relative to the first and second chambers.

Preferably, the pressing member 5 then has two chamfers 51a and 51b by means of which it presses the two deformable seals 4a, 4b against the two respective circular edges 12d, 12e formed by the bottom 12a and the two internal lateral walls 12b and 12c of the annular groove on.

As shown in Figure 2, only two bores are to be made in the rotor 1 if the latter comprises two pressure chambers 11 and 12, instead of three bores such as 11, 12 and that of Figure 1, in one art prior.

In addition, as is immediately apparent from the comparison of Figures 1 and 3, only three bores are to be provided in the rotor with three pressure chambers of a distributor according to the invention, instead of five bores in the prior art .

Finally, the reduction in the number of bores makes it possible to reduce the length of the distributor along the direction of axis 3.

Claims

1. Rotary hydraulic distributor comprising first and second distribution members (1, 2) capable of undergoing relative rotation, and sealing means (la, lb, 4a, 4b, 5a, 5b), the first distribution adopting an at least partially cylindrical shape with axial symmetry and adjusting for rotation inside a bore (2a) of complementary shape to the second distribution member (2), each of the first and second distribution members comprising at less than the first and second pressure chambers (11, 12, 13; 21, 22, 23) spaced apart from each other in an axial direction and subjected to respective pressures, the difference of which is variable, each chamber of each dispensing member being likely to be located opposite the corresponding chamber of the other dispensing member to be subjected to the same pressure as it, and the sealing means comprising: a peripheral annular groove (la, lb) formed in the first distribution member, a deformable annular seal (4a, 4b) insulating from one another, in an axial direction, the first and second pressure chambers, and an annular pressing member (5a, 5b) resting on the internal surface of said bore for pressing the deformable seal inside the groove, characterized in that the annular groove (le) communicates with the second pressure chamber (12) of the first distribution member, forms the periphery of this chamber and adopts a substantially rectangular section, in that the pressing member (5) maintains the deformable seal (4a, 4b) against the bottom (12a) of this annular groove while pressing it against that of the internal lateral walls (12b , 12c) of this groove which is closest to the first pressure chambers (11, 21) and in that the pressing member (5) is pierced with a bore (50) opposite the second pressure chamber of the second distributor.

2. Distributor according to claim 1, characterized in that said deformable seal (4a, 4b) is toroidal with circular section at rest.

3. Dispenser according to claim 1, in which the first and second dispensing members each comprise a third pressure chamber (13, 23) arranged, in an axial direction, on the side of the second chamber (12, 22) which is opposite to that where the first chamber is located, characterized in that it comprises a second deformable seal (4b) insulating the second and third pressure chambers and in that the pressing member (5) housed in the annular groove at the periphery of the second pressure chamber of the first dispensing member maintains this second seal in a manner equivalent to that which it maintains the first seal.

4. Distributor according to claim 3, characterized in that the pressing member (5) has two chamfers (51a, 51b) by which it presses the two deformable joints (4a, 4b) against the two respective circular edges (12d, 12e ) that form the bottom (12a) of the annular groove at the periphery of the second pressure chamber of the first dispensing member and the two internal side walls (12b, 12c) of this groove.