FR2878928A1 - VALVE UNIT WITH ELECTRONIC CONTROL - Google Patents

Abstract

Electronically controlled valve installation (10) in particular for a motor vehicle brake system, comprising a solenoid valve (12) with a freely movable valve member (52) for controlling a valve seat (56) between two hydraulic fluid channels (20, 22). A hydraulic bypass that bypasses the valve seat (56) is equipped with a non-return valve (14). When bleeding the brake system, the valve member (52) of the solenoid valve (12) can be pulled against the valve seat (56) and prevent complete evacuation of the brake system. The valve installation (10) according to the invention avoids this difficulty. For this, the non-return valve (14) comprises a housing (78) through which the fluid passes and having at each opposite end a valve orifice (80, 82) controlled by the same valve member (81). This non-return valve (14) movable relative to the solenoid valve (12) is blocked in its end-of-travel position by the application of pressure. In the unblocked state, the non-return valve (14) cooperates with an anti-blocking protection installation (84) which does not allow the non-return valve (14) to come into the blocked position.

Description

Field of the invention

  The present invention relates to an electronically controlled valve unit in particular for a braking system of a motor vehicle comprising: - a solenoid valve and a check valve, the solenoid valve having a valve body axially guiding a pusher, - an armature actuated by the electromagnetic coil for acting on the pusher as well as - a valve member cooperating with the pusher for controlling the opening section of the valve seat provided between the inlet and the outlet of the valve unit according to the control electromagnetic coil, a hydraulic fluid connection between the inlet and outlet constituting a hydraulic bypass to the valve seat and in which is installed the check valve, the check valve closing the hydraulic fluid connection in the direction of the passage and releasing it in the opposite direction.

  STATE OF THE ART One such valve unit is known for example according to DE 19 635 693 A1. This known valve unit consists of a solenoid valve or electromagnetic valve and an integrated check valve. The electromagnetic valve or solenoid valve shown in Figure 2 of the above-mentioned document consists of a valve member in which a longitudinally movable pusher is guided freely. The pusher cooperates with an armature subjected to the action of an electromagnetic coil. This coil generates a magnetic field when it is energized and this field moves the armature. The armature stroke is transmitted by a pusher to a poppet member which controls a valve seat. This valve seat is located between an inlet and an outlet of the solenoid valve. A hydraulic fluid pressure connection in the form of a bypass converts the valve seat. This hydraulic fluid connection under pressure is controlled by a non-return valve. The non-return valve then closes the hydraulic fluid supply in the direction of the passage and releases this connection in the opposite direction. The non-return valve is permanently integrated in the solenoid valve and does not have a clean housing.

  To modulate the brake pressure of a vehicle brake system, several such valve units are required. These valve units are part of a hydraulic module and are controlled by an electronic control unit. The control unit uses, among other things, the rotational speed signals provided by sensors fitted to the vehicle wheels and the pressure signals supplied by sensors of the hydraulic circuits according to the control signals.

  When this hydraulic module is installed in the vehicle and its connection is made on the various brake lines connected to the wheel brakes, the system is purged. For this purpose, the pressurized gas is evacuated from the zones through which the hydraulic fluid passes and the gas is replaced by brake fluid. It is established that this evacuation operation is a safety operation because gas inclusions could give the brake system undesired compressibility and under these conditions, it is necessary to avoid them at all costs.

  Particularly in the case of electromagnetic valve or solenoid valve whose valve members are held in a defined base position to better regulate the low pressure differences, without return spring, it may happen that the valve members are drawn in their valve seat by the depression prevailing during the evacuation operation and thus may close the connected parts of the hydraulic circuit. In particular, if in this position the non-return valve of the bypass is in the blocking position, the bleeding of the brake system may be dangerously unclear.

  Advantages of the invention The present invention relates to an electronically controlled valve unit of the type defined above, characterized in that the non-return valve is movably installed with respect to the valve unit and in its end position. it is locked by the application of hydraulic pressure, and the check valve is equipped with a non-return valve lock which holds it in its open position as long as the check valve does not occupy its end position race.

  This valve unit according to the invention offers the advantage of keeping intact the possibility of purging the hydraulic system. Blocking of the branches of the hydraulic circuit is avoided by necessarily keeping the check valve of the valve unit open during the evacuation process. Only when filling the hydraulic system with pressurized liquid and making the first pressure rise in the hydraulic circuit, is it finally defined the relative position of the non-return valve with respect to the electromagnetic valve. . In this end position, the non-return valve performs the function for which it is intended. The invention thus improves the possibility of using electromagnetic valves without spring and allows the brake system to work with a particularly high degree of control precision, especially at low pressure differences.

  According to another advantageous feature, the check valve comprises a check valve housing traversed by the fluid, separate from the hydraulic fluid, having valve openings at its opposite ends and a valve member housed in the housing and controlling the valve openings, and the anti-lock system passes through the valve opening as long as the check valve is not in its end position. Thus, there is a particularly economical embodiment, simple and easy to achieve.

  According to another advantageous characteristic, the non-return valve housing is mechanically locked to the solenoid valve and the anti-lock system is fixedly installed on the solenoid valve.

  Thus, the relative position of the non-return valve vis-à-vis the electromagnet is particularly reliable through the mutual attachment of the two parts.

  The invention is particularly economical if, according to another advantageous characteristic, the electromagnetic valve comprises an insert fixed to the valve body and which comprises a mounting chamber for the non-return valve, and the anti-lock device and the abutment. are performed on this insert. The insert can be made of plastic and thus allows a shaping such that the anti-lock installation and the stop of the check valve can be formed in one piece, practically in a cost-neutral manner and without require additional mounting.

  A springless non-return valve according to claim 6 is particularly advantageous in terms of cost and assembly, and furthermore avoids accidental return of liquid under pressure even for the smallest pressure differences. Drawings The present invention will be described below in more detail with the aid of an exemplary embodiment shown in the accompanying drawings in which: - Figure 1 is a longitudinal section of the electronic valve unit according to the invention FIG. 2 shows the detail X of FIG. 1 on an enlarged scale and in three dimensions, the non-return valve being presented in its unhooked position, and FIG. 3 mounting the non-return valve of FIG. hung end of race.

  Description of an embodiment

  According to FIG. 1, the valve unit 10 consists of an electromagnetic valve or solenoid valve 12 incorporating a non-return valve 14. The valve unit 10 is housed in a mounting chamber 16 of a valve block 12 of a hydraulic module being hooked by a connection by the shape, for example by crimping the material of the valve block 18. The valve block 18 comprises hydraulic fluid channels 20, 22 opening into the mounting chamber 16 to achieve the hydraulic connection with the valve unit 10. A hydraulic fluid channel 20 running horizontally in the block forming the housing constitutes the inlet; a vertically directed hydraulic fluid channel 22 constitutes the outlet of the valve assembly 10. The two hydraulic fluid channels under pressure 20, 22 are sealingly closed with respect to the installed valve unit 10, and by relative to the environment.

  The valve unit 10 is composed inter alia of a valve body 24. It is preferably a metal piece, turned, provided with a radial flange 26 made by turning and used for matting in the valve block 18 and a guide bore passing in the longitudinal direction. The guide bore 28 receives a pusher 30 guided by its outer periphery against the inner wall of the bore. Longitudinal grooves 32 are distributed at the peripheral surface of the pusher 30. These grooves ensure the hydraulic pressure balance by making a hydraulic fluid connection under pressure between the one and the other end faces of the pusher 30. The end Valve body 24 outside the valve block 18 has an armature 34 whose outside diameter covers the front surface of the valve body 24. The end of the armature 34 facing the valve body 24 is applied against the outer end of the pusher 30. The armature 34 is housed movable in the longitudinal direction in an armature chamber 36; the armature chamber 36 is delimited by a valve dome 38. This dome 38 has a cupola-domed shape at its outer end and its second inwardly open end is fixed to the outer diameter of the valve body 24 .

  The end of the electromagnetic valve 12 projecting from the valve block 18 carries an electromagnetic coil 40 with its coil body 44 carrying the coil 42; this coil is fitted on the end of the electromagnetic valve. The power supply of the electromagnetic coil 14 is by electrical contacts 46 located in Figure 1, behind the dome 38 of the valve and protruding therefrom. The magnetic circuit formed by the electromagnetic coil 40 once energized closes by a flux guide plate 48 carried by the valve body 24 on the valve block side and a flux guide body 50 surrounding the coil coil 42. and covering it also at the level of its frontal face. The flux guide body 50 is in contact with the flux guide plate 48 by a magnetic connection at their peripheral surface.

  At the opposite end of the armature 34, the pusher 30 cooperates with a valve member 52. The latter has a reduced internal diameter relative to the pusher 30 and substantially in the middle of its axial ex-tension, there is provided a transient segment 54 which joins a cylindrical pin 58 cooperating with the valve seat 56 and having a free end with a spherical curvature. The valve member 52 may be attached to the pusher 30 or made in one piece therewith.

  A valve seat 56, controlled by the poppet member 30, is formed in the valve seat sleeve 60. This sleeve is a separate piece. The valve seat sleeve 60 is installed on a projecting portion 62 of a valve insert 64 and passes therethrough into the guide bore 28. The valve seat 56 is itself embodied as a cone and at the end facing the pusher, there is provided a stepped inner contour for the valve sleeve 60. This inner contour forms, in connection with the valve seat 56, a throttling point 66 before joining a cylindrical segment receiving the valve sleeve 60 at the projecting portion 62 of the valve insert 64.

  The valve insert 64, made of plastic material, for example by injection, is held by a force connection to the valve body 24 by means of a filter support 68 made in the same way. The valve insert 64 and the filter support 68 are located inside the mounting chamber 16 of the valve body 24 in the valve block 18. The valve support 68 filters with the aid of a filter cloth not appearing, coated, the dirt contained in the hydraulic fluid under pressure arriving in the valve unit 10, before this liquid under pressure can pass, once the valve seat 56 opened, through the hydraulic fluid connection under pressure from the valve insert 64 to the outlet 22 of the sou-popule unit 10. The incoming pressurized fluid first passes into a valve chamber 70 connected to the outlet 20 and made between the valve insert 64 and the valve body 24. This chamber 70 is connected by a plurality of connecting channels 72 in the valve body 24 to a mounting chamber of the valve member 74. The chamber of mounting of the valve member 74 is delimited on one side by the sleeve of orpape 60 and the other by the front surface of the pusher 30; at the periphery, the delimitation is ensured by the wall of the guide hole 28 in the valve body 24. It should be noted that the pusher 30 and the valve member 52 connected thereto move freely, that is to say without being biased by a return spring being guided in the guide bore 28. This allows to regulate the slightest pressure differences at the valve seat 56 by an appropriate electronic control of the electromagnetic coil 42 without the resulting valve characteristic curve has inconvenient discontinuities as is the case if using return springs.

  The valve chamber 70 as described has, next to its connection with the valve member mounting chamber 74, a second connection to a mounting chamber for the check valve 76. This check valve mounting chamber 76 is Also provided in the valve insert 64 and opens to the outlet 22 of the valve unit 10. The mounting volume of the check valve 76 is dimensioned so that the check valve 14 can be installed captively and all of the first relatively movable with respect to the valve body 24 of the electromagnetic valve 12. The check valve 14 itself comprises a housing 78 traversed separately by the liquid under pressure. This housing may be a parallelepiped or barrel-shaped hollow body with valve orifices 80, 82 provided at the two opposite ends. A check valve member, for example in the form of a free-moving ball, is mounted in the check valve housing 78. For this, the check valve housing 78 may be formed of, for example, two housing halves. which can be assembled, preferably plastic or sheet metal, with a housing sleeve opening on one side, the open end of the housing being crimped after mounting the check valve 81 forming the second opening 82 An anti-lock system 84 cooperates with the non-return valve 14 and with a stop 86 at the ventilation orifice 80, 82 provided opposite. The anti-blocking device 84 and the stop 86 are preferably made in one piece with the valve insert 64.

  The check valve 14 is fixedly attached by exerting a hydraulic pressure on the valve seat 64. In the exemplary embodiment, the casing 78 of the non-return valve 78 has a peripheral annular groove 88 into which its catching nose penetrates. 92, the resilient tabs 90 made on the valve insert 64. In the end position, hooked on the non-return valve 14, shown in Figure 1, the anti-lock system 84 is out of service while the stop 86 passes through with a large radial clearance, the lower valve opening 82, located on the output side. The stop 86 thus prevents the valve member 81 of the non-return valve from closing the opening 82 hydraulically. The embodiment and installation of the non-return valve 14 on the seat insert 64 is hereinafter explained. help of figures 2 and 3.

  Figure 2 shows the check valve 14 in a position in which the spring 92 of the valve insert 64 and its latching nose 92 are not yet housed in the peripheral annular groove 88 of the valve housing 78. The check valve 14 is in this position at the end of the assembly operation of the hydraulic module in the valve unit 10. This corresponds to the moment when the hydraulic module has not yet been pressurized. In this position, the anti-lock system 84, provided on the armature side, passes through the upper valve opening 80 of the non-return valve 14, while the stop 86, at the second valve opening 82, to the opposite, is out of reach. The anti-lock system 84 is formed as a cylindrical pin on the valve insert 64; the outer diameter of this branch is significantly smaller than that of the valve opening 80 associated therewith. The anti-lock protection device 84 holds the valve member 81 housed in the housing 78 away from the valve opening 80. This prevents the valve member 81 from closing the hydraulic fluid pressure connection. between the inlet 20 and the outlet 22 as soon as there is a slope acting towards the inlet 20, as is the case, for example, for evacuating the hydraulic system. The hydraulic fluid connection under pressure thus kept open constitutes a bypass of the valve 52 of the solenoid valve 12 (FIG. 1). Even though the valve member 52 of the solenoid valve 12 was pulled into its blocking position by the pressure differential applied at its valve seat 56, the hydraulic system could still be discharged into the bypass by the valve. antiretour 14, necessarily open in the derivation. In the case of a greater pressure at the inlet 20 than the outlet 22, the valve member 81 of the check valve could close the opening 82 on the outlet side so that the pressure prevailing at this time lead the pusher 30 of the electromagnetic valve 12 in its open position. A higher pressure will be encountered at the inlet 20 as soon as the hydraulic unit is traversed by hydraulic fluid, for example with an anti-corrosion agent before it is supplied.

  Figure 3 shows the difference from Figure 2 for the check valve 14 occupying its end position. The resilient tabs 90 are hooked by their noses 92 in the annular groove 88 of the check valve housing 78, so that the check valve 14 is attached to the valve seat 64. In this end position, due to the hydraulic forces applied, the check valve 14 will be fed for the first time with hydraulic pressure by the hydraulic module. The dimensioning of the annular groove 88, the elastic tongues 90 and the latching nose 92 determines the height of the pressure level required for this purpose. In the end position, the anti-lock system 84 is out of engagement and thus the upper opening 80 on the side of the armature will be open. The stop 86 made in one piece with one of the tabs 90 as a bow-shaped extension with an axially aligned head passes through the second opposed valve opening 82. This prevents the new opening 82 from being closed by the valve member 81. In this end-of-travel position, the non-return valve 94 can perform the function for which it is intended by hydraulically closing the bypass as soon as A pressure difference, acting in the direction of the upper valve opening 80, is applied to the check valve 14. A pressure difference acting in the oppositing direction can be eliminated through the valve opening 82 to the exit 22.

Claims (6)

  1) Electronically controlled valve unit (10), in particular for a braking system of a motor vehicle comprising: - a solenoid valve (12) and a non-return valve (14), the solenoid valve (12) having a valve body ( 24) axially guiding a pusher (30), - an armature (34) actuated by the electromagnetic coil (40) to act on the pusher (30) as well as - a valve member (52) cooperating with the pusher (30) for controlling the opening section of the valve seat (56) provided between the inlet (20) and the outlet (22) of the valve unit (10) as a function of the electrical control of the electromagnetic coil ( 40), a hydraulic fluid connection between the inlet (20) and the outlet (22) forming a hydraulic bypass towards the valve seat (56) and in which the check valve (14) is installed, the check valve (14) ) closing this hydraulic fluid connection in the direction of the passage and releasing it in the opposite direction, c characterized in that the check valve (14) is movably mounted with respect to the valve unit (10) and in its end position is locked by the application of hydraulic pressure, and the check valve (14) is equipped with a check valve (84) which holds it in its open position as long as the check valve (14) does not occupy its end position.   Electronically controlled valve unit according to claim 1, characterized in that the check valve (14) comprises a non-return valve housing (78) traversed by the fluid, separate from the hydraulic fluid, having valve openings (80, 82) at its opposite ends and a valve member (81) housed in the housing (78) and controlling the valve openings (80, 82), and the anti-lock system (84) passes through the valve opening (80, 82) as long as the non-return valve (14) is not in its end position.   3) electronically controlled valve unit according to claim 1 or 2, characterized in that the housing (78) of the check valve is mechanically locked to the solenoid valve (12) and the anti-lock system (84) is installed in a fixed manner on the solenoid valve (12).   4) electronically controlled valve unit according to claim 2 or 3, characterized in that the valve opening (82) opposite the locking device (84) cooperates with a mechanical stop (86) when the check valve (14) is in the end position, this stop prohibiting the closing of this valve opening (82) to the valve member (81).   Electronically controlled valve unit according to one of Claims 2 to 4, characterized in that the electromagnetic valve (12) has an insert (64) fixed to the valve body (24) and which has a mounting chamber for the non-return valve (14) and the anti-lock device (84) and the stop (86) are formed on this insert.   Electronically controlled valve unit according to Claim 1, characterized in that the non-return valve (14) does not have a valve spring and the valve member (81) has a free-moving ball housed in the housing. (78) of the check valve.