Alliedsignal Inc.

Allied Corporation

The Bendix Corporation

Bosch Systemes De Freinage

Donald A Crumb

Robert F Gaiser

Richard A Zander

Robert K Wilson

John E Steer

William F Dillon, Jr

Hugh E Keyes

Thad A Nevitt

A master cylinder having a first housing with an axial bore therein which is connected to a second housing of a reservoir. The axial bore has a first replenishing port surrounded by a first boss and a second replenishing port surrounded by a second boss. A first radial bore in the first boss extends from the first replenishing port while a second radial bore in the second boss extends from the second replenishing port. First and second spigots which extends from the second housing are respectively located in the first and second radial bores to provide first and second flow communication paths from the reservoir to the axial bore. The first housing is secured to the second housing by a connecting arrangement characterized by a first pin that extends through the first boss and first spigot and a second pin that extends through the second boss and the second spigot to respectively retain first and second seals within the first and second radial bores without the introduction of side load forces which may provide a leak path between either the first or second flow communication paths and the surrounding environment.

Master cylinder reservoir retention means

A brake system (10) having a master cylinder (14) connected to wheel brakes (24, 26) of a vehicle through remote compensation valves (20, 22). The master cylinder (14) has a two piece housing (66, 84) with a bore (74, 86) therein. First (32) and second (34) pistons are located in the bore (74, 96) by a sleeve and bearing arrangement (98, 82). Return springs (104, 110) in the bore (74, 96) position the first (32) and second (34) piston to define first (106) and second (114) chambers in the master cylinder (14). The two piece housing has first (22) and second (90) flanges that are joined together by hook (94, 94', 94', 94'') and slots (73, 73', 73', 73'') to form a unitary structure and by bolts (47, 47') which further compress seals (102) by joining the first flange (72) to a brake booster (12) to assure that the bore (114) is sealed from the surrounding environment.

Master cylinder and brake booster arrangement for a brake system

A remote compensation valve (20) through which pressurized fluid from a master cylinder (14) is communicated to the wheel brakes (24, 26) of a vehicle. The compensation valve (20) has a housing (200) with a bore (202) therein for retaining a shuttle piston (210). The shuttle piston (210) has a first land (212) separated from a second land (214) by a groove (216) and an axial bore (218) connected to the groove (216) by a radial bore (224). A first spring (250) carried by the piston (210) urges a poppet valve (244) toward a seat (230) to control the communication of pressurized fluid through the axial bore (218) to an outlet port. A second spring (254) located in the housing (200) urges the piston (210) toward a rest position where the first land (212) engages a pin (234) of a tilt valve (232) to establish communication between the source of fluid and the bore (202) and the poppet valve (244) is seated on the piston (210) to prevent communication through the axial bore (218). A manual input force on a first end (262) of a movable stop pin (250) brings a second end (266) into engagement with the poppet valve (244) to initiate communication between the compensation port (206) and the master cylinder (14) to remove any air from the master cylinder (14).

Remote compensation valves for a master cylinder in a brake system

Structure for caging a return spring of a master cylinder to define limits for an operational chamber. The structure includes a first cylindrical member which engages a first piston and a second cylindrical member which engages a second piston with the return spring being located between the first and second cylindrical members. A stud which has an irregular shaped end member is retained in a groove in the second piston by the second cylindrical member and mated with a head member to define the limits for the return spring between the first and second cylindrical members and correspondingly the maximum size of the chamber within a bore of a master cylinder.

Master cylinder with caging means to secure return spring limiting stud

The master cylinder (30) includes primary and secondary pistons (42, 52) each of which has a center compensation valve member (44, 60). An abutment member or pin (38, 40) extends across a bore (36) of the master cylinder (30) adjacent ends of each of the pistons (42, 52) and the pins (38, 40) are each engaged by shafts (45, 64) of the spring biased valve members (44, 60) of the primary and secondary pistons (42, 52). An output rod (43) of a vacuum booster (41) to which the master cylinder (30) is attached disposes the primary piston (52) slightly spacedapart from the respective pin (40) in an at-rest position. The primary piston (52) includes a self-adjusting compensation center valve seat (70) located within the primary piston (52), the valve seat (70) sealingly and slidingly movable relative to the primary piston (52). The valve seat (70) extends through a rear opening (59) of the piston (52) to engage the respective pin (40). The engagement of the valve seat (70) and shaft (64) of the valve member (60) ensures that the valve head (62) is always positioned a predetermined distance (C) from the valve seat (70) in the at-rest position of the primary piston (52). The brake pedal 'feel' can be closely controlled to minimize soft pedal feel during brake actuation by minimizing stackup tolerances within the master cylinder (30) such that the valve member (60) of the primary piston (52) closes very quickly.

Center valve master cylinder with self-adjusting compensation center

A center-compensation master cylinder (10) has first (20) and second (30) pistons with center-compensation valve members (27, 37). The pistons (20, 30) have diametrically extending slots (22, 32) at central axial portions thereof through which extend pin members (53, 54) to effect opening of the valve members (27, 37) when the pistons (20, 30) are in at-rest positions. A first spring (29) extends between a head (24) of the first piston (20) and the second piston (30), and a second spring (39) extends between an end (15) of the bore 0 (I4) and the head (34) of the second piston (30). The first spring (29) is caged via a caging mechanism (60) ensuring that the first (20) and second (30) pistons will travel simultaneously when the center-compensation valve members (27,37) are closing. The caging mechanism (60) is adjustable to control accurately the location of the second piston (30 ) in an at-rest position. The caging mechanism comprises an end part (47) non-rotatably and axially coupled with longitudinal extensions (40) of the head (24) of the first piston (20), a member (65) adjustably coupled with a threaded end (47C) of the end part (47), and a head (66) of the member (65) abutting a cage end member (70) which seats at a back portion (31) of the second piston (30). The cage end member (70) is cup-shaped and includes a radially flared lip (74) providing a seat for one end of the first spring (29) while the other end of the first spring (29) is received at a diametral extension (28) of the first piston (20).

Center valve master cylinder with adjustable caged primary spring

A caging arrangement for limiting the extension of springs in a bore. The caging arrangement includes cylindrical members which are connected to pistons in a master cylinder. The cylindrical members which are joined to the pistons and communicates the force of piston return springs to urge the pistons toward a rest positions while a valve return springs retained by the cylindrical members urges valves toward stops to control fluid communication between a reservoir and pressure chambers associated with the pistons.

Spring caging for a master cylinder

The vented screw-in proportioning valve (30) of the present invention comprises a proportioning valve body (32) having threads (36) on the proportioning valve body (32) connected with threads (23) of a master cylinder boss (22). A stepped bore (38) of the proportioning valve body (32) includes a differential area piston which is generally U-shaped, a pair of seal members (52, 54) located axially spaced-apart and disposed about the piston (40) in order to define a vented chamber (60), a vent (62) extending through the proportioning valve body (32) and communicating with the vented chamber (60), a snap ring (70) located adjacent an inlet (34) of the proportioning valve body (32), a retainer (80) spring-biased into engagement with the snap ring (70), a spring (90) disposed between the retainer (80) and an interior cavity (42) of the piston (40) in order to bias the piston (40) toward the outlet (33), and a fluid seal (50) disposed adjacent a head (46) of the piston (40).

Vented screw-in proportioning valve

A cap for a reservoir of a master cylinder having a disc member with a plurality of perpendicular guides located on a fixed radius from the center of the disc member for aligning a cylindrical body secured thereto. The cylindrical body has an annular flange with a tapered peripheral surface thereon extending from an edge of a shoulder formed adjacent the annular flange. A diaphragm has an annular base connected to an apex section by a first conical leg and a center section connected to the apex section by a second conical leg. The diaphragm has a plurality of ribs that engage the disc member when an annular lip is located on a shoulder of the cylindrical body. When inwardly projecting tabs on the annular edge of the disc engage corresponding arcuate projections extending from the cylindrical neck to fix the cap to the reservoir, the tapered peripheral surface on the flange of the cylindrical member engage the first conical leg to provide a radial force which urges the first conical leg into engagement with the cylindrical neck of the reservoir to form the primary sealing for the reservoir while the plurality of ribs are compressed between the disc and and top of the cylindrical neck to from the secondary sealing for the reservoir.

Cap for a reservoir of a master cylinder

A master cylinder (12) having a switch (70) which is activated by either a magnet (78) carried by a float (76) in a reservoir (40) or a pin (66) moved by a differential area piston (52). The switch (70) had a first blade (82) connected a source of electrical current (106) through an indicator light (124) and a second blade (88) connected to an electrical ground (114). A reed switch (100) is connected to the first (82) and second (88) blades and responds to the magnet to close an electrical circuit to operate the indicator light (124) if a low fluid level is present in the reservoir (40). A first contact (96) on the first blade (82) is positioned in switch 70 by a non-electrical conductive actuation pin (66) that extends through the housing (22) of the master cylinder (12). A second contact (94) on the second blade ( 88) has a projection (92) that engages the housing (22) of the master cylinder (12) to define a fixed location for the first contact (94) and establish a fixed gap between the first (94) and second (96) contacts. If a pressure differential is created in the master cylinder (12) between the fluid pressure supplied to operate the wheel brakes (18) and (20), the differential area piston (52) moves and brings the second contact (96) into engagement with the first contact (94) to close the electrical circuit and activate the indicator light (124).

Master cylinder with fluid level and pressure failure detection

A master cylinder having a housing with a first bore therein for retaining a pair of pistons which move in response to an input force and develop fluid pressure to effect a brake application. A second bore in the housing carries a differential area piston connected to the pressure chambers. A reed switch retained in the housing is aligned with a first magnet located on a float in a reservoir and a second magnet is attached to the differential area piston. A ferromagnetic shield located between the reed switch and second magnet has first and second openings located in a plane on either side of the reed switch. Should a failure occur in either pressure chamber, the differential area piston moves to allow magnetic field to pass through the openings in the shield and activate the reed switch to develop a warning signal and inform an operator of a failure mode condition in the master cylinder.

Master cylinder with fluid level and pressure failure detector

The positioning ring (44) for a hydraulically operated warning device (80) may be utilized for any hydraulically movable piston or sleeve (52) which, when properly assembled, causes a warning device (80) to effect an initial mode of response. The positioning ring (44) has a reduced inner diameter portion (41) separated from an enlarged inner diameter portion (43) by way of a radial shoulder (42). The enlarged inner diameter portion (43) abuts a shoulder (17) of a surrounding housing (11) and the radial shoulder (42) abuts a shoulder (59) of the piston or sleeve (52). The housing (11) may contain a warning device (80) which engages the piston or sleeve (52) such that if the piston or sleeve (52) is displaced in an axial direction the warning device (80) is operated. Should the centering ring (44) be mis-assembled or not included in the assembly, either the misassembled positioning ring (44) or the lack of the positioning ring ( 44) permits the piston or sleeve (52) to be moved to a position where the warning device (80) is operated to provide an indication that the positioning ring (44) is either misassembled or missing from the assembly.

Positioning ring for a hydraulically operated warning device

The proportioning valve assembly (40, 140) may be screwed into a complementary-shaped opening in a master cylinder (10). The valve assembly (40, 140) includes a differential area piston (50, 150) biased by a spring (70, 170) toward the outlet (21, 121) which communicates with the rear brakes. The master cylinder (10) includes a pair of passageways (16, 18) which communicate primary fluid pressure and secondary fluid pressure directly to the differential area piston (50, 150) of the proportioning valve assembly (40, 140) to displace the piston (50, 150) to a balanced position. If there is a failure of pressure in the primary brake circuit, the proportioning valve assembly (40, 140) actuates the differential area piston (50, 150) to permit fluid flow to bypass the piston (50, 150) and be communicated directly to the rear brakes of the vehicle.

Primary and secondary pressure-balanced proportioning valve

A proportioning valve (40) is disposed within a stepped bore (13) of a master cylinder (10). The proportioning valve (40) defines with the stepped bore (13) a primary pressure receiving chamber (26) and a secondary pressure receiving chamber (28). The proportioning valve (40) includes a two-part piston (58) which includes a primary piston part (52) and a secondary piston part (54) coupled together by a lost motion coupling (53, 55). The piston parts (52, 54) are biased apart by a spring (78), and a sleeve (43) is disposed about the two-part piston (50). Seals (46, 47, 69) are disposed about the primary piston part (52), sleeve (43) and secondary piston part (54) to define an intermediate vented chamber (90), wherein a vent (19) communicates with a reservoir. Pressure failure within the primary receiving chamber (26) causes the primary piston part (52) to be displaced and close off the vent (19 ) so that fluid pressure is trapped within the intermedaite chamber (90) to prevent the secondary piston part (54) from effecting the metering of fluid flow through an outlet (21).

Pressure-balanced proportioning valve with vent-controlled bypass

The unitary poppet valve assembly (50) comprises an annular retainer (52) having an open end (54) and an opposite end (55) with a small diameter opening (56) therein. The annular retainer (52) has a plurality of fingers (58) extending laterally therefrom for engagement with the body (12) of a proportioning valve assembly (10). A poppet (70) comprises a poppet head (72) extending radially outwardly from a longitudinal shaft (74), and an oppositely disposed abutment (76). The shaft (74) extends slidably through the small diameter opening (56) in the annual retainer (52), the abutment (76) engaging the retainer (52) adjacent the opening (56). A spring (60) is disposed between a corner or shoulder (57) of the annular retainer (52) and a shoulder (77) defined between the poppet head (72) and poppet shaft (74). The poppet (70) includes a central through opening (78) extending through the abutment (76) and to the head (72), wherein the opening (78) communicates with a lateral through opening (80) of the shaft (74). The unitary poppet valve assembly (50) may be inserted directly within an inlet opening (13) of the proportioning valve assembly (10) so that the fingers (58) engage the body (12) of the proportioning valve assembly (10).

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Granger, IN, United States of America

Donald A Crumb