US3108615A

US3108615A - Reaction valve construction

Info

Publication number: US3108615A
Application number: US59914A
Authority: US
Inventors: Maxwell L Cripe
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1960-10-03
Filing date: 1960-10-03
Publication date: 1963-10-29
Anticipated expiration: 1980-10-29
Also published as: GB927688A

Description

3,103,615 REACTEQN VALVE C(DNSTR'UCTKGN lidarrweli L. Cripe, South Bend, End, assignor to The Bendix Corporation, South Bend, End, a corporation of Delaware Filed Get. 3, 1%), Ser. No. 599M- 4- Claims. (Cl. 137--625.66)

The present invention relates to fluid pressure servomotor control valves; and more generally to reaction producing control valve structures.

An object of the present invention is the provision of a new and improved control valve for a fluid pressure servomotor and the like which employs less parts and is simpler and cheaper to produce than prior art structures with which applicant is familiar.

The invention resides in certain constructions and com binations and arrangements of parts; and further objects and advantages of the invention will become apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment described with reference to the accompanying drawing forming a part of this specification, and in which:

The solitary FIGURE of the drawing is a longitudinal cross sectional view of a hydraulic pressure intensifying unit embodying principles of the present invention.

As previously indicated the invention in the present application has to do with a new and improved control valve structure particularly suited for the control of a fluid pressure servomotor; and in order that its construction and operation may be fully appreciated, a brief description of the structure which it is intended to control will now be given. The fluid pressure intensifying unit shown in the drawing, and in which the present invention is embodied, generally comprises a hydraulic fluid pressure intensifying cylinder A having a fluid displacing piston B therein which is actuated by means of the power operated movable wall or diaphragm C of the fluid pressure motor D that is suitably bolted to one end of the hydraulic fluid pressure intensifying cylinder A.

The fluid displacing piston B is a generally cup-shaped structure 19 having a cup seal 12 on its outer periphery which is slidingly sealingly received in the longitudinal bore 14 of the fluid pressure intensifying cylinder A. The cup-shaped structure is adapted to be stroked in its bore 14 by a push rod 16, one end of which is suitably attached to the diaphragm structure C. The other end of the push rod 16- is positioned in the cupshaped structure 10 and is loosely secured thereto by means of a cross pin 13 the ends of which are loosely received in a cross bore 26' that extends through the sidewalls of the cup-shaped structure 10'.

The fluid displacing piston B is normally held in its retracted position shown in the drawing by a power piston return spring 22 that is positioned between an end wall of the fluid pressure motor D and the dia phragm structure C, and which causes the cross pin 18 to abut the rear surface of the cross bore 29 to draw the fluid displacement piston B to its return or normal position show-n in the drawing. Rearward movement of the fluid displacing piston B is limited by an annular stop or washer 24 that is positioned against a shoulder 26 formed in the end of the bore 14 adjacent the servomotor D by means of a counterbore 28. The annular stop washer 24 is held in position against the shoulder 26 by means of a spauldite annular guide washer 3t) and a perforated bushing 32. The perforated bushing 32 is prevented from withdrawal of the counterbore 28 by means of a snap ring 34-. A suitable seal is provided between the push rod 16 and the sidewalls of the counter- 3.3%,615 Patented Get. 29, 1%63 bore 28 by means of a cup seal as held apart from the snap ring 34 by means of an annular lip spreader 38. The cup seal 35 is retained within the counterbore 23 by means of a spauldite back-up washer 40, retaining washer 42 and snap ring 44.

Fluid pressure from a primary fluid pressurizing device or a master cylinder, not shown, is communicated to the region rearwardly of the fluid displacing piston B through the pressure inlet connection or port 46 so that hydraulic fluid pressure from the inlet port 45 helps to drive the fluid displacing piston B down its bore; and the fluid which is displaced by the fluid displacing piston B is communicated to the driven braking structure, not shown, by means of the outlet connection (now shown). In order that the system which is connected to the outlet port will be maintained full of hydraulic fluid even though leakage etc., should occur, the cupshaped structure 10 is provided with a fluid compensating passage 50 to communicate the inlet port 46 with the outlet port when the piston B is in its retracted position shown in the drawing. The passage 50 shown is formed by means of a small axial bore 52 in the front end of the cup-shaped structure 10 and the lateral drilling 54. The end of the push rod 16 is provided with a ball end 56 which, when the push rod 16 is actuated, closes oil the end of the small axial bore 52 and prevents pressure that is generated in the longitudinal bore 14 from being communicated to the pressure inlet 46.

The structure so far described is caused to be actuated by means of a control valve structure E which controls the pressure differential which is applied across the power operated movable wall structure C. The fluid pressure motor D shown is of the vacuum suspended type, in which vacuum of the same intensity is normally communicated to the opposite sides of the movable wall C when the unit is in the deenergized condition shown in the drawing, and which admits amospheric pressure to the power chamber 58 on the back side of the movable wall structure C during actuation of the motor. Vacuum is continually communicated to the front power chamber 66 by means of a suitable vacuum connection 62 which is normally connected to the mani fold of an automotive engine. The control valve structure E generally comprises a vacuum chamber 64 that is continually connected to the front power chamber 66 by a passageway 66, a control chamber pressure 68 that is continually communicated to the rear power chamber 58 by means of conduit 70, and an atmospheric chamber 72 that is communicated to the atmosphere by the air inlet '74. The vacuum chamber 64 is formed by means of a cavity in the cast housing of the pressure intensifying cylinder A and is separated from the control chamber 68 by means of a diaphragm structure 76 which will later be described. The control chamber 68 is separated from the atmospheric chamber '72 by means of a rigid internal partition 78 of a cover structure as suitably bolted down upon the radial outer edges of the diaphragm structure '76 to thereby seal off the control chamber '68. The rigid internal partition 78 has an atmospheric valve port 82 to provide comrnunication between the atmospheric chamber 72 and control chamber 6%, and the diaphragm structure 76 has a tubular structure 84 aligned with respect to the atmospheric valve port 82 for communicating the vacuum valve chamber 64 and the control chamber 68. A generally spoolshaped poppet member 36 having its small diameter center portion 88 extending through the atmospheric valve port 82 is provided so that the outer flange 90 of the poppet member 36 abuts the outer face of the partition 78 to control atmospheric communication therethrough while the inner flange 92 of the poppet member is adapted a to be abutted by the hub portion 9 2- of the diaphragm 76 surrounding the tubular member 34 for controlling vacuum communication through the tubular member. The outer flange 9b is normally biased against the par tition 78 to close off the port 82 by means of a coil spring 96 and the diaphragm structure 76 is normally biased away from the inner flange )2 by means of a coil spring 93.

The diaphragm structure 76 is retained upon the end the tubular member 34 by means of an annular back-up plate ltlt) which is slipped over the end of the tubular member 84 and is abutted against a shoulder 162 in the outer periphery of the tubular member. The diaphragm 76 is slipped over the end of the tubular member into abutment with the back-up plate m2, and is held thereagainst by means of an annular retaining plate and the coil spring 98.

According to principles of the present invention, the diaphragm '76 not only provides the reaction force required against control movement, but simultaneously provides the valve seat that abuts the flange $2 and closes off communication through the tubular control member 34. This is accomplished by the hub portion of the diaphragm which is molded as an integral portion of the diaphragm 7-6 to tightly surround the outer periphery of the tubular member 84 and project a slight distance outwardly of the end of the member 34. The portion of the hub 94 which projects beyond the end of the tubular member 84- rnust be controlled within limits so that it does not deform over and interfere with the abutment of the end of the tubular member 84 with the flange 92; and it must be, at the same time, sufficiently strong so as to effect an adequate seal with respect to the flange 92. The seating end of the hub 94 is preferably rounded away from the outside periphery of the tubular member 84' so that its deformation against the flange $2 of the poppet member does not cause the elastomeric material from which the hub M is made to flow inwardly around the end edge of the tubular member 84. By the provision of a suitable radius on the end of the hub portion 94-, the end of the tubular member 84 is permitted to move up into engagement with the flange 92 while the end of the hub 94- is being deformed against the flange 92. After direct bearing contact is achieved between the tubular member 84 and the flange 92, no (further opening exists through which the elastomeric hub 94 can be extruded, to help hold the diaphragm '76 upon the tubular member 84, the outer periphery of the member 84 is provided with an annular recess 1% into which a radially inward projection of the diaphragm 76 extends. The diaphragm 76 is molded into the general form shown and the squeezing action induced by the spning 93 and pressure forces holds the elastomeric material in the recess 1% so that the tubular portion 84 cannot be Withdrawn out of the diaphragm. 76. The retaining plate 1&4 may also have an overlying flange 108 to further hold the diaphragm in the recess 1%.

Actuation of the control valve structure B so far de scribed i s bad by reason of the hydraulic pressure that is supplied to the inlet pressure connection 4-6. The inner end of the tubular member 84 is a generally solid projection having suitable seals thereon that are received in the hydraulic bore 110 which communicates with the hydraulic chamber on the back side of the fluid displacing piston B to which the pressure inlet connection 46 communicates. In the normal condition of the structure, its parts are in the position shown in the drawing, and vacuum is communicated to the front power chamber Gil. Actuation of the unit is initiated by pressure from the master cylinder, not shown, entering the inlet pressure connection 46; whereupon the tubular member 84- is moved sufliciently to bring the end of the hub 94 into engagement with the flange 92 of the poppet member 38. Abutment of the hub 94- with the flange 92 closes off fur ther vacuum communication with the rear power chainl 53; and thereafter causes tie end of the hub $4 to be in 'med by an amount allowing the end of the tubular member 8 to abut the flange 92. Continued movement of the tubular member 84 lifts the outer flange of the poppet member out of engagement with the partition to pen it air pressure from the air chamber 72 to enter the control chamber 68 and thence pass to the rear power chamber 53. As air pressure builds up in the control chamber 63, it causes the end of the hub 94 to be biased radially inwardly into tight engagement with the end of the tubular member 8d but is prevented from squeezing therepast by the tight engagement of the tu- 'bular member with the face of the flange 92. Pressure build-up in the rear power chamber 58 and the resulting movement of the power diaphragm C causes the ball end of the push rod 16 to close off the compensating port 50 and thereafter move the fluid displacement piston B forwardly down the bore 14 of the fluid intensifying cylinder A. Fluid displaced from the bore 14, of course, passes out through the pressure outlet connection to operate the braking system to which it is connected. During the time that the flange 9% is out of engagement with the partition 715, the pressure in the control chamber 68 continues to increase thereby exerting a larger and larger force uponv the diaphragm '76 which biases it in a direction away from the partition member 78. The flange 92 of the poppet 83 remains in sealing abutment with the hub 94 until the outer flange 9O seals the atmospheric port 82 through the partition member 78 thereby preventing a further build-up in pressure in the rear power chamber 58.

When it is desired to release the braking effort, the pressure supplied to the inlet connection 46 is reduced thereby allowing the forces on the diaphragm structure '76 to move the control member 84 inwardly, and thereby move the hub 94 out of sealing engagement with the flange '92 of the poppet member 88. Vacuum is thereby communicated to the rear power chamber 58dec-reasing the pressure differential across the power diaphragm C to allow the hydraulic pressure in the bore 14 and the force of the return spring 22 to move the displacement piston 13 rearwardly. When a desired reduction in braking effort is accomplished, further reduction in pressure in the inlet port 46 is prevented; whereupon a slight further flow of vacuum to the rear power chamber 53 permits the fluid displacement piston B to move rearwardly by an amount which displaces hydraulic fluid against the control member 84, which in turn moves outwardly to again bring the hub into sealing engagement with the poppet flange 92. Thereafter further reduction in the rear power chamber 53 is prevented, and the hydraulic piston B becomes stationary. A complete removal of pressure supplied the inlet connection 46 permits the control member 84 to move inwardly until its shoulder 112 abuts a cooperating shoulder in the housing member, in which position the hub 94 remains out of engagement with the rear flange 92 of the poppet member. Pressure differential across the diaphragm C is thereby completely removed allowing the diaphragm return spring 22 to pull the hydraulic piston B to its retracted position. When the cup-shaped structure ill abuts the stop washer 24, the ball end of the push rod 16 moves out of engagement with the end of. the cup surrounding the compensating port 50; and thereafter the inlet connection 46 is communicated to the outlet connection to permit pressure compensation across the hydraulic piston B.

It will be apparent that the objects heretofore enumerated as well as others have been accomplished and that there has been provided a simplified control valve mechanism for providing both a reaction and valve port sealing function. While the invention has been described in considerable detail, I do not wish to be limited to the particular construction shown and described; and it is my intention to cover hereby all novel adaptations, modifications and arrangements thereof which come within the practice of those skilled in the art to which the invention relates and which come within the purview of the following claims.

I claim:

1. A simplified reaction producing control valve structure comprising: a housing having a chamber therein, an axially extending control member having a generally tubular flow conducting end portion in said chamber, said end portion of said control member having a generally radially extending diaphragm back-up surface on its periphery facing the end of said portion, a molded diaphragm of an elastomeric compound positioned against said back-up surface with its radially outer edge sealed with respect to said housing, said diaphragm having an axially extending annular hub portion which projects away from said back-up surface a slight distance beyond the end of said tubular portion of said control member, and a poppet member for sealing abutment with the end of said hub, said hub being yieldable to permit said end of said control member to abut said poppet member after said hub forms a seal therewith.

2. A simplified reaction producing control valve structure comprising: a housing having a chamber the-rein, an axially extending control member having a generally tubular flow conducting end portion in said chamber, said end portion of said control member having a generally radially extending diaphragm back-up surface on its periphery facing the end of said portion, a molded diaphragm of an elastomeric compound positioned against said back-up surface with its radially outer edge sealed with respect to said housing, said diaphragm having an axially extending annular hub portion which projects away from said back-up surface a slight distance beyond the end of said tubular portion of said control member, a poppet member for sealing abutment with'the end of said hub, said hub being yieldable to permit said end of said control member to abut said poppet member after said hub forms a seal therewith, the periphery of said control member between said back-up surface and its end having a recess therein, and said molded diaphragm having a radially inwardly extending portion locked in said recess.

3. A simplified reaction producing control valve structure comprising: a housing having a chamber therein, an axially extending control member having a generally tubular flow conducting end portion in said chamber, said end portion of said control member having a generally radially extending diaphragm back-up surface on its periphery facing the end of said portion, a molded diaphragm of an elastomeric compoundpositioned against said back-up surface with its radially outer edge sealed with respect to said housing, said diaphragm having an axially extending annular hub portion which projects away from said back-up surface a slight distance beyond the end of said tubular portion of said control member, a poppet member for sealing abutment with the end of said hub, said hub being yieldable to permit said end of said control member to abut said poppet member after said hub forms a seal therewith, the periphery of said control member between said back-up surface and its end having a recess therein, said molded diaphragm having a radially inwardly extending portion locked in said recess, an annular holddown .washer positioned against said diaphragm for forcing said diaphragm toward said back-up surface, and a valve return spring biasing said annular washer toward said back-up surface.

4. A simplified reaction producing control valve structure comprising: a housing having a chamber therein, an axially extending control member having a generally tubular flow conducting end portion in said chamber, said end portion of said control member having a generally radially extending diaphragm back-up surface on its periphery facing the end of said portion, a molded diaphragm of an elastomeric compound positioned against said back-up surface with its radially outer edge sealed with respect to said housing, said diaphragm having an axially extending annular hub portion which projects away from said back-up surface a slight distance beyond the end of said tubular portion of said control member, a poppet member for sealing abutment with the end of said hub, said hub being yieldable to permit said end of said control member to abut said poppet member after said hub forms a seal therewith, the periphery of said control member between said back-up surface and its end having a recess therein, said molded diaphragm having a axially inwardly extending portion locked in said recess, an annular holddown washer positioned against said diaphragm for forcing said diaphragm toward said back-up surface, said hold down washer having a generally axially extending flange abutting the surface of said hub and holding said hub locked in said recess, and a valve return spring biasing said annular washer toward said back-up surface.

References Cited in the file of this patent UNITED STATES PATENTS 2,393,524 Pant Jan. 22, 1946 2,797,665 Chouings July 2, 1957 2,805,647 Ingres Sept. 10, 1957 2,910,051 Hupp Oct. 27, 1959

Claims

1. A SIMPLIFIED REACTION PRODUCING CONTROL VALVE STRUCTURE COMPRISING: A HOUSING HAVING A CHAMBER THEREIN, AN AXIALLY EXTENDING CONTROL MEMBER HAVING A GENERALLY TUBULAR FLOW CONDUCTING END PORTION IN SAID CHAMBER, SAID END PORTION OF SAID CONTROL MEMBER HAVING A GENERALLY RADIALLY EXTENDING DIAPHRAGM BACK-UP SURFACE ON ITS PERIPHERY FACING THE END OF SAID PORTION, A MOLDED DIAPHRAGM OF AN ELASTOMETRIC COMPOUND POSITIONED AGAINST SAID BACK-UP SURFACE WITH ITS RADIALLY OUTER EDGE SEALED WITH RESPECT TO SAID HOUSING SAID DIAPHRAGM HAVING AN AXIALLY EXTENDING ANNULAR HUB PORTION WHICH PROJECTS AWAY FROM SAID BACK-UP SURFACE A SLIGHT DISTANCE BEYOND THE END OF SAID TUBULAR PORTION OF SAID CONTROL MEMBER, AND A POPPET MEMBER FOR SEALING ABUTMENT WITH THE END OF SAID HUB, SAID HUB BEING YIELDABLE TO PERMIT SAID END OF SAID CONTROL MEMBER TO ABUT SAID POPPET MEMBER AFTER SAID HUB FORMS A SEAL THEREWITH.