FR2654059A1 - PRESSURE CONTROL VALVE WITH SPACING PART FORMING PLUNGER. - Google Patents

Abstract

The pressure control valve according to the invention comprises a valve body (1) defining a bore (11), a spacer (4) disposed in the valve bore and intended to move therein as a result of 'a thrust to adjust the outlet pressure (P1, P2), electromagnetic actuators (5a, 5b) to drive the spacer (4) in an axial movement to increase the outlet pressure in the state active, mechanical support springs (4e, 4f) constantly exerting a force pushing the spacer in a direction such that there results an axial movement of the spacer to lower the outlet pressure, plungers (54a, 54b) associated with electromagnetic actuating devices to cause axial displacement of the spacer piece, these plungers being integral with the spacer piece. The pressure control valve according to the invention can be used in particular in motor vehicle power steering systems.

Description

The present invention relates to a pressure control valve

  useful in particular for power steering systems for motor vehicles and other industrial devices. A pressure control valve of this type is described in the preliminary (unexamined) patent publication

  Japanese (Tokkai) Showa 63-231003, for example A

  conventional pressure gauge of this type has a bore

  in a valve body A spacer is

  placed in the bore to adjust the flow of fluid in a

  power supply, an exit line and a conduct of

  emptying The spacer is associated with an electromagnetic solenoid

  magnetic drive to drive it in one direction to increase the

  outlet pressure in the outlet pipe The space piece-

  It is also associated with a servo means for providing a servo pressure to return to the initial position. In addition, the spacer is normally pushed

  in an initial position by a support spring.

  In a conventional pressure control valve of this type, the force for driving the spacer is produced in the solenoid and transmitted to the spacer by means of an actuating rod. such a construction limits the possibility of reducing the length

  In addition, in the previously proposed construction,

  the supporting spring is arranged between the space piece-

  Therefore, the solenoid housing of the solenoid

  support pressure, it is necessary to adjust the axial position of the solenoid housing which makes it difficult and complicated to adjust

the support load.

  Also, in order to remedy the disadvantages of the prior art,

  cited above, the object of the present invention is to provide

  install a pressure control valve that solves

  the problems of the prior art as described above.

  above. The present invention also aims to propose

  a reduced axial size pressure control valve.

  Another object of the present invention is to propose a pressure control valve by means of which it is easy to

set the support load.

  In order to achieve the objects which have just been mentioned, the pressure control valve is provided with a spacer which is integral with the plungers.

  electromagnetic solenoids so that the electromagnetic force

  developed by the solenoids acts directly on the valve spacer Due to the fact that the spacer and the solenoid plungers form a single piece, it is possible to reduce the axial size of the valve. With this construction, the bearing springs can be arranged in the axial direction outside the solenoids to facilitate the adjustment of the bearing load to be exerted on the part.

spacing of the valve.

  Thus, the pressure control valve according to

  This invention comprises a valve body defining a bore

  valve which extends axially inside the body of

  pope, a spacer disposed in the valve bore and adapted to move therefrom as a result of a thrust to adjust the outlet pressure according to its axial position, devices

  electromagnetic actuators for driving the space piece-

  in axial movement to increase the output pressure to the active state, mechanical support springs constantly exerting a force urging the spacer in such a direction that axial movement of the spacer to lower the outlet pressure, plungers associated with the electromagnetic actuators to cause the axial displacement of the spacer, these plungers being of a piece

with the spacer.

  The bearing springs may be arranged axially outside the electromagnetic actuators to allow external adjustment of the bearing force. The bearing springs may be associated with end caps screwed onto the casing of the casing. valve to adjust The bearing force of the bearing springs.

  But other advantages and features of the invention

  tion will become more apparent in the detailed description which follows and

  Referring to the accompanying drawings, given by way of example only, of the preferred embodiment of the invention, and in which Ls:

  FIG. 1 is a section of the preferred embodiment

  This is a graph showing the variation of the outlet pressure as a function of the control current.

to a Lenoid so.

  Referring now to the drawings, and particularly to FIG. 1, it is seen that the preferred embodiment of the pressure control valve is the present invention.

  Link to a first exit line Si and a second line

  output pressure 52 for applying output pressures P1 and P2 Output pressures P1 and P2 produced by the pressure control valve are used to control a steering system by the rear wheels, for example The system,

  The steering to the right of the rear wheels is done by increasing

  In the same way, the left-hand steering of the rear wheels is effected by increasing the output pressure in the second output duct 52 as is known, the steering control by the wheels. back is performed in response to an operation of

  steering for the front wheels The amp Litude and the direction of bra-

  The following are determined by taking into account different control parameters. The rear wheel steering system is described in US Pat. No. 4,778,023 issued on October 18, 1988, 4,926,954 issued May 22, 1990, 4,657. 102 issued on 14 April 1987 and 4,720,790 issued on 19 January 1988, which describe four-wheel steering systems

  a steering control by the rear wheels.

  As shown in FIG. 1, the preferred embodiment

  The present invention comprises a valve body 1. The valve body 1 comprises a valve body 1.

  a Lésage axia L 11 L'aésage 11 presents first and second ori-

  output fills 11a and 11b The first and second outlets 11a and 11b are respectively connected to the first and second

  second outlet pipes 51 and 52 in an axially inter-

  mediate between the first and second outlets 11a and 11b

  there is a supply line 2 which communicates with the

  On the other hand, externally, in the axial direction, first and second outlet openings 11a and 11b are disposed a drain line 3 which opens into the bore. The supply line 2 is connected to a pump P which acts as a source of fluid pressure Furthermore, the drain pipe 3 is

  connected to a tank T in which it returns the fluid

  award-winning fluid pressure in the drain line 3 and the

  T tank is equal to atmospheric pressure.

  A spacer 4 is disposed in the bore 11 of the valve for movement along the axis of the bore

  Following a push Spacer 4 has pre-

  first and second bearing surfaces 4a and 4b The first bearing surface 4a defines variable orifices q and r with the edges of the first outlet orifice 11a. Similarly, the second bearing surface 4b defines variable orifices S and t with the edges of the second outlet orifice 11b Support surfaces 4c and 4d are also

  formed at both axial ends of the spacer 4.

  Two actuators 5a and 5b are provided at the two axial ends of the spacer 4 which are intended to control the position of the spacer in the bore of the valve. the spacer 4, the fluid communication between the supply line 2 and the outlet ports 11a and 11b and between the outlet ports and the drain line 3 is selectively established as a result of the selective opening of the variable orifices q, r, s and t The actuating devices 5a and 5b comprise housings 52a and 52b which fit on the axial ends of the valve body 1 The liquid tightness between the housings 52a and 52b and the axial ends of the valve body 1 is provided by seals 81a and 81b The ends

  of the housings 52a and 52b are closed by solenoid bodies

  No. 51 a and 51 b electromagnetic coils 53a and 53b are arranged in the annular chambers defined inside the housings 52a and 52b of the actuating devices

  magnetically non-conductive or insulating 55a and 55b are dis-

  placed between the inner periphery of the electromagnetic coils 53a and 53b and the associated peripheral surfaces of the housings 52a and 52b of the actuating devices and solenoid bodies 51a

and 51 b.

  The casings 52a and 52b of the actuators define axial bores 57a and 57b of diameter slightly greater than that of the valve bore 11. The axial ends 54a and 54b of the spacer 4s The axial ends 54a and 54b of the spacer 4 serve as plungers for the electromagnetic actuators. are magnetically non-conductive or insulating material, are rigidly attached to respective axial ends 54a and 54b The stop elements 7a and 7b extend into through openings 71a and 71b formed in the bodies of solenoid 51 a and 51 b to allow movement

  of the stop elements 7a and 7b with respect to the openings

  71a and 71b, rings 72a and 72b are disposed between the outer periphery of the stop members and the inner periphery of the through openings. The axially outer ends of the through openings 71a and 71b open into bores 73a. The outer ends of the larger diameter bores 73a and 73b are closed by adjustable caps 8a and 8b which cooperate by screwing with the solenoid bodies 51a and 51b. rooms 73a and 73b which

  are intended to receive support springs 4 e and 4 f.

  Means axially internal of the support springs 4 e and 4 f rest on arresting devices 41a and 41b provided with support flanges 42a and 42b Counter-nuts 74a and 74b are arranged on the plugs

8a and 8b.

  The stop elements 7a and 7b have first and second piston bores 63a and 63b First and second pistons

  64A and 64B drivers with rounded ends are arranged in the

  The first and second piston rings 63a and 63b are in alignment with first and second piston rings 63a and 63b so as to move therein by thrust. a and 61b which communicate with the first and second outlets 11a and 11b. As a result, the fluid pressures at either of the first and second outlets 11a and 11b are exert on the respective inner ends 65a and 65b of the first and second pistons

drivers 64a and 64b.

  The coils 53a and 53b of the solenoids are excited by

  a control current from a unit that controls the amplifier

  study and the sense of the pressure difference at the level of the first

  and second outlet pipes 51 and 52 This difference in pressure

  sion can perform for example a steering control of the rear wheels. The operation of the preferred pressure control valve embodiment will now be described in accordance with the

present invention.

  In the absence of control current in the solenoid coils 53a and 53b, both are held at rest. As a result, the two ends 54a and 54b of the

  spacers 4, which serve as divers, are not

  electromagnetic forces coming from the coils 53a and 53b In this state, there is an equilibrium between the forces exerted by the support springs 4 e and 4 f in the neutral position of the spacer 4 In this position, a fluid communication between the supply line 2 and the first and second outlet openings 11a and 11b is maintained via the variable orifices r and t. In addition, fluid communication is established between the first and second outlets 11a and 11b. and second outlet openings 11a and 11b and the discharge line 3 via the orifices

variables q and s.

  As a result, the fluid pressures in the first and

  second outlet pipes 51 and 52 are equal to each other.

  Thus, when the first and second output pipes are connected to the steering system by the rear wheels, the wheels

  back are held in the neutral position.

  When a control current is applied to the coil 53a of the first actuator 5a, this coil is

  excited and pulls the axial end 54a As long as the tractive force

  The magnetic coil 54a is smaller than the force of the support spring 4e, the spacer 4 remains in the neutral position despite the application of the magnetic force When the magnetic force of the coil 53a becomes greater than the force of the spring, that is to say when the control current exceeds the value m (see Figure 2), the spacer 4 and the stop element 7a move against the spring force

support 4 e.

  The area of passage of the variable orifices r and S increases

  As a function of the displacement of the spacer 4 at the same time, the passage area of the variable orifices q and t decreases progressively.

  of compressed fluid enters the first outlet pipe 51.

  On the contrary, fluid communication between the supply line

  2 and the second outlet pipe 52 is substantially blocked thereby, the fluid pressure supplied to the first outlet pipe 51 is greater than that which is

  provided at the second exit line 52.

  This large fluid pressure at the first exit port 11a is returned to the servo bore 61. Thus, this larger fluid pressure is exerted on the first pilot piston 64a, and thus on the adjustable cap

  8 a The force corresponding to this pressure acts as a reaction force

  to push the spacer 4 away. As a result, the movement

  The spacing piece 4 is axially interrupted. As a result, the amplitude of the axial displacement of the spacer 4 is

  proportional to the intensity of the control current (Figure 2).

  A similar but opposite operation takes place when the control current is applied to the coil 53. As a result,

  the fluid pressure in the second outlet line 52 increases

  proportionally to the intensity of the control current

applied to the reel 53 b.

  To adjust the support load, the counter

  nuts 74a and 74b to allow the adjustable plugs 8a and 8b to rotate In this state, if the plugs are turned

  8 a and 8 b in the direction of greater tightening,

  On the contrary, if the adjustable caps 8a and 8b are turned in the direction of a

  slackening, the load can be reduced.

  It is to be understood that the invention is not limited to the preferred embodiment described above by way of illustration and that those skilled in the art may make various modifications and

  various changes without departing from the scope of the invention.

tion.

Claims (3)

  A pressure control valve, characterized in that it comprises a valve body (1) defining a bore (11) which extends axially inside the valve body, a   spacer (4) disposed in the valve bore and des-   moved as a result of a push to adjust the pressure   output voltage (P 1, P 2) according to its axial position, electromagnetic actuators (Sa, 5b) for driving the spacer (4) in an axial movement to increase the outlet pressure to the active state, mechanical bearing springs (4 e, 4 f) constantly exerting a force pushing the spacer into   sense that results in an axial movement of the piece of space.   for lowering the outlet pressure, plungers (54a, 54b) associated with the electromagnetic actuators for causing axial displacement of the spacer (4),   these divers being in one piece with the spacer.   2 pressure control valve according to claim 1, characterized in that said bearing springs (4 e, 4 f) are   arranged axially outside said operating devices   (5 a, 5 b) to allow external adjustment of the support force.   3 pressure control valve according to claim 1, characterized in that said bearing springs (4 e, 4 f) are associated with end caps (8 a, 8 b) which are screwed onto said valve body (1) for adjusting said support force of said support springs.