JPH0247608B2 - SHARYOBUREEKYOYUATSUSADOTOKUMITATETAI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic cylinder assembly for use in vehicle brakes of the type in which a piston operating within a bore in a housing is movable within the bore in response to hydraulic pressure that produces a brake application force. Regarding.

Hydraulic cylinders of the type described herein may incorporate or be associated with a slack adjuster that determines the retracted position of the piston in the retracted and brake-off position to determine the brake clearance. The problem is arranging the slack adjuster so that it does not react to the deflection of the brake element when the brakes are applied. Otherwise, the slack adjuster would tend to "over-adjust" and excessive brake clearance would have to be provided to compensate for such "over-adjustment."

According to the invention in a hydraulically actuated tube of the type described herein incorporating an assembly acting as a strut for determining the retracted position of the piston, said assembly comprises: a first clamping member moving with the piston; interengaging parts that cooperate to form a releasable pawl in conjunction with a resilient device that includes an adjuster member and typically acts between the piston and the clamp member to bias the engagement parts; a clamping member and a regulator member, wherein axial movement of the clamping member relative to the piston in an outward brake application direction in response to brake application hydraulic pressure within the bore increases engagement of the engagement component. A piston and a clamping member are provided with engaging ramps constructed and arranged such that the regulator member cooperates when movement of the regulator member in the direction of brake application exceeds a distance sufficient to remove the brake clearance. A spring-loaded catch is provided within the bore which is adapted to allow additional movement of the clamp member in the same direction to move the clamp member axially relative to the adjuster member to increase the effective length of the strut. The pawl increases the force of the spring device until the engagement force of the engagement part exceeds the force of the spring loaded catch at a predetermined point. The pawl is released against a force, at which point the pawl re-engages and prevents further relative axial movement between the two members, after which further movement of the strut in conjunction with the piston is prevented by the pawl. is provided by movement against a spring load.

The predetermined point is the point at which the brake is fully applied, after which the brake element begins to deflect.

The regulator of the present invention adjusts only as a result of excessive piston movement due to wear of the brake lining, and does not respond to excessive piston movement due to deflection of the brake element after sufficient braking has been applied. The device can be said to be load insensitive.

The clamping member is housed within a bore within the piston and includes a piston portion operable within the bore and a plurality of angularly spaced integral resilient fingers extending toward the open end of the bore. The free end carries pawls that engage axially spaced teeth on the regulator member, both of which are provided with ramps that engage ramps on the piston.

When the actuating barrel has a pair of opposed acting pistons operating within the bore of the housing, a spring loaded catch is received within the bore of the second piston into which the regulator member protrudes; A head is supported on the free end of the member, the outer end of which defines a stop that engages a surface at the inner end of the bore cavity to determine the relative retracted position of the two pistons; The inner end is adapted to abut a spring loaded catch.

The spring-loaded catch has a compression spring that is held in a partially compressed restraint by a cage, and a radial flange at the inner end of the cage that compresses the regulator member when actuating the actuating barrel. Forming an abutment portion that engages the head.

Some embodiments of the present invention will be described below with reference to the accompanying drawings.

The brake illustrated in FIGS. 1 and 2 is of the conventional extended type, in which a rotatable grinding disk 1 with a grinding lining is located between the disks 1 and a fixed pilot 5, Pressure plates 3, 4 centrally positioned by 6, 7 are adapted to engage oppositely spaced radial surfaces within the housing 2. The spheres are housed in cooperating oppositely inclined recesses on the adjacent faces of the pressure plates 3,4.

Application of the brake is initiated by moving the pressure plates 3, 4 in angularly opposite directions, such that the tendency of the sphere to climb the slope defined by the end faces of the recess causes the pressure plates to move relatively away from each other. is moved axially. This forces the grinding disk into engagement with the surface of the housing 2. The pressure plates 3, 4 then rotate with the disks until one is locked by the engagement of the lugs 8, 9 on the respective plates 3, 4, after which the continued angular movement of the other plate causes a servo action. give.

Housing 2 for parking or in case of emergency.
a tension rod extending through a radial opening 11 of the rod and connected to the outer ends of a pair of toggle links 12, 13 whose inner ends are pivotally connected to the respective pressure plates 3, 4; 10 applies the brake mechanically.

In normal road braking, the lugs 16,1 on the pressure plate
The brakes are applied hydraulically by a hydraulic cylinder 15 acting between 7 and 7. The lugs 16, 17 are angularly spaced from the toggle links 12, 13 and the actuating barrel is accessible from a second radial opening 18 in the housing 2 which is closed by a removable plate 19.

The actuating barrel 15 includes a cylinder 20 having an axial through-bore bore 21 open at both ends in which a pair of pistons 22, 23 acting in opposite directions engage the lugs 16, 17. Operate. Each piston 22, 23 operates through a seal 24 near the adjacent outer end of the cylinder 20 and supports a seal 25 near the inner end. Piston 2 within hole cavity 21
A pressure space 26 defined between adjacent inner ends of housing 2 is connected to the main working barrel through a passage 27 in the housing that is accessible from the outside of housing 2 .

The automatic slack adjuster assembly 30 is housed within the actuating barrel 15 and is received in axially opposed bores 31, 32 in the pistons 22, 23, respectively.

The regulator assembly has a clamping member 33 housed within the bore 31, a piston portion 34 operating within the bore, and a forming portion 35 projecting from the open end of the bore 31.
The first clamping member 33 has a plurality of axially extending resilient fingers supporting the molded portion 35, the outer edge of the molded portion 35 being sloped to wedgely engage a complementary sloped surface 37 on the piston 22; The edges have claws 36. The regulator member 38 is connected to the first clamp member 3
3 into the bore cavity 32 and is provided with a plurality of axially spaced teeth 39 against which the pawl 36 is engaged by the resiliency of a spring ring 40 supported on the piston 22. It's like that.
The free end of the regulator member 38 supports an enlarged head 41 whose outer end engages a surface at the inner end of the bore 32 so that the inner ends of the pistons 22, 23 are closed. Limit separation. Clamping member 33 and regulator member 38 thus act as a support for determining the retracted position in the brake release position and thereby the braking clearance.

A spring loaded catch 42 fits within the bore 32. The catch has a restrained compression spring 43 at each end abutting between a circular clip 44 in the bore 32 and a flange 45 at the inner end of the cylindrical cage 46, with a flange 47 at the opposite end of the cylindrical cage engages clip 44; Typically, the abutment surface 48 defined by the inner end of the head 41 is spaced from the flange 45 by a distance corresponding to the braking gap, and the pistons 22, 23
are held in the retracted position by the return springs of the pressure plates 3,4.

When the brakes are applied hydraulically, the high pressure fluid within the pressure space 26 urges the pistons 22, 23 in opposite directions, urging the lugs 16, 17 relative to each other as described above. During this movement of the pistons 22, 23, as the braking gap is removed, the head 41 moves relative to the flange 45, and the brake is fully applied and pressure is also exerted on the piston part 34, forming the When the portion 35 is urged in the axial direction, the head 41 presses against the flange 45.
come into contact with. At this time, due to the wedge action, the claw 36
The gripping force of the pawl defined by the engagement of the teeth 39 is increased. If it is indicated that the movement of the head 41 relative to the flange 45 is excessive when the actuating barrel is actuated and adjustment for lining wear is necessary, then the adjuster member 38 moves the ring 40
is pulled out from the clamp member 33 against the elasticity of the strut, thereby increasing the effective length of the strut. Clamp member 3
This action continues until the pawl due to the pressure on piston 3 exceeds the force of spring 43, after which the piston 2
Further relative movement between 2 and 23 is caused by spring 43
This is covered by the compression of

The point at which the pawl is fixed and prevents further extension of the strut is chosen as the point before the brake is fully applied and the force generated by the braking pressure is used to cause deflection of the braking element.

When the brake is released, the pistons 22, 23
returns to its inactive, retracted position, and the inner ends of both pistons are separated by a greater distance determined by the extended length of the strut.

In order to restore the fully extended strut to its original position, the teeth 39 are separated by angularly spaced axial recesses and are connected to the pistons 22, 23.
By moving the claw 36 angularly by an appropriate amount.
can be fitted into the recess, after which the clamping member 33 and the adjuster member 38 can be moved towards each other without resistance.

In alternative embodiments, a male-to-female thread formation may be used instead of the pawls and teeth.

The actuating barrel and regulator assembly described above can be used in drum type brakes. For example, it can be used for two leading shoes, or one trailing shoe, or for dual-servo type brakes. When the brake is of the dual-servo type or operates as a dual-servo type in one mode, the strut is strong enough to transfer thrust from the primary shoe to the secondary shoe when the brake is applied.

As illustrated in FIG. 3, the actuator and regulator assembly is installed into a shoe drum brake of a vehicle. The cylinder 20 has adjacent shoe ends 50,5
The outer ends of the pistons 22, 23 extend outwardly to form bosses 52, 53. Boss 52, 53
Notches 54 and 55 are provided at the outer ends of the spools to receive shoe ends 50 and 51, respectively.

Seals 25 are present in close proximity to the inner ends of the two pistons 22, 23, and seals 24 are omitted. Annular sealing boots 26, 27 are provided at each end of the cylinder 20, with the inner and outer thickenings or beads of each boot connecting the bosses 52, 53 and the cylinder 20.
each radial groove 56 at an adjacent end of 0;
Accepted in 57.

The construction and operation of the actuating barrel and regulator are otherwise the same as described above with reference to FIGS. 1 and 2, and corresponding parts have been provided with corresponding reference numerals.

The actuating tube and adjuster assembly described above may also be used in actuating tubes for vehicle disc brakes, particularly sliding side caliper type disc brakes. In this type of disc brake, a second polishing pad is provided within the fixed housing between the polishing pad and an axially movable clamping member, such as a yoke, for applying a second polishing pad to the opposite surface of the disc. There is a piston facing the.

In another configuration, shown in FIG. 4, the actuating tube and regulator assembly is incorporated into a side-to-side axially movable caliper disc brake.

The brake has a fixed drag-bearing member of generally contoured shape (not shown) spanning the periphery of the rotatable disc. Opposed grinding pad assemblies that engage opposite sides of the disc are mounted within the drag bearing member and move toward or away from the drag bearing disc guide surfaces on the pad assemblies when the brakes are applied. The pad assembly is guided as follows.

A caliper 60 with opposing prongs 61, 62 spans the disc and ground pad assembly and carries drag on circumferentially spaced guide surfaces which may be constituted by guide pins. It is guided to slide axially on the member.

The actuating barrel/regulator assembly is assembled into a fork 62 provided with an axial bore 63 having a stepped configuration. The piston 22 is located in the inner portion 6 of the large diameter bore 63.
4, the piston 23 is omitted and the bore 32 is constituted by the outer portion 65 of the bore 63 of smaller diameter. The head 41 is adapted to slide through a seal 66 in the wall of the bore 65, and the outer end of the head 41 is provided with a conical recess 67 which engages one end of a locking dolly or post 68. The other end of the support column 68 is received in a notch 69 of the brake application shaft 70 . The shaft 70 has a bush 71 inserted into a lateral hole 72 of the prong 62.
It is journalled so that it rotates inside.

The piston 22 slides through a seal 72 in the wall of the bore portion 64, and a resilient sealing boot similar to boot 26 may also be coupled between the piston 22 and a retaining groove 73 in the inner end of the bore 63. .

The construction and operation of the actuator/regulator are otherwise the same as described with reference to FIGS. 1 and 2, and corresponding parts have been given corresponding reference numerals.

[Brief explanation of drawings]

FIG. 1 is an end view of the expandable brake; FIG. 2 is an enlarged longitudinal sectional view of the hydraulic cylinder assembly used in the brake of FIG. 1; and FIG. 3 is an internal shoe drum similar to FIG. FIG. 4 is a longitudinal cross-sectional view of the disc brake for a vehicle; FIG. 15... Working tube, 20... Housing, 22, 23
... Piston, 31, 32 ... Hole cavity, 33 ... Clamp member, 34 ... Piston portion, 35 ... Inclined surface, 36
...Claw, 37...Slope, 38...Adjuster member, 39...
Teeth, 40... Elastic device, 41... Head, 43... Spring,
45...Flange, 46...Cage, 48...Abutting portion.

Claims (1)

[Claims] 1. The piston 22 is connected to the hole 31 in the housing 20.
The piston 22 is movable within the bore 31 in response to hydraulic pressure acting therein to generate a brake application force.
A hydraulically actuated barrel assembly incorporating an assembly acting as struts 33, 38 to determine the retracted position of a first clamp member 33 and an adjuster member movable with the piston 22. 3
8, both members including interengaging parts to form a releasable pawl in cooperation with a resilient device 40 which normally serves to bias the interengaging parts into engagement. The interengaging parts cooperate with each other to move the clamping member 3 in an outward brake application direction in response to brake application hydraulic pressure within the bore 31.
Said piston 22 and clamping member 33 are provided with interengaging ramped surfaces 37, 35 constructed and arranged to enhance engagement of said interengaging parts when said piston 22 moves axially relative to piston 22. A spring-loaded stop 42 is provided within the bore 31 so that when movement of the regulator member 38 in the direction of braking exceeds a distance sufficient to remove the brake clearance, the spring-loaded stop 42 further movement of the clamping member 33 in said direction causes the regulator member 38 to
to increase the effective length of the struts 33, 38 to define an adjusted retracted position of the piston 22 when brake pressure is relieved, and to reduce the engagement force of the interengaging parts. The pawl is released against the force of the resilient device until the spring-loaded pawl 42 exceeds the force of the spring-loaded pawl 42 at a predetermined point, at which point the pawl re-engages. to prevent further relative axial movement between the two members, after which further movement of the struts 33, 38 in conjunction with the piston 22 is prevented by the spring load 4.
3. A hydraulically actuated cylinder assembly characterized in that the movement of said catch 42 is compensated for by movement of said catch 42 against 3. 2. The clamp member 33 is housed in the bore 31 of the piston 22, and includes a piston portion 34 that operates within the bore 31 and a piston portion 34 that protrudes toward the open end of the bore 31 and has the adjustment member at the free end. The clamping member 33 includes a plurality of angularly spaced integral resilient fingers supporting pawls 36 that engage axially spaced teeth 39 on the pawls 38 .
An actuating barrel assembly according to claim 1, characterized in that both are provided with an inclined surface (35) that engages with an inclined surface (37) on said piston (22). 3. The clamping member 33 includes a piston portion 34 that fits within and operates within a bore 31 in the piston 22, with a thread formation between the clamping member 33 and the adjustment member 38. provided, the piston portion 34 is connected to the piston 2
2. An actuating barrel assembly as claimed in claim 1, characterized in that it is provided with an inclined surface (35) that engages with an inclined surface (37) on the actuating tube assembly (2). 4 having a pair of counter-acting pistons 22, 23 operating within the bore 21 of the housing 20, said spring loaded catch 42 operating within the bore 32 of the second piston 23;
The regulator member 38 is housed within and protrudes into the bore 32 , the free end of the regulator member 38 supporting a head 41 , the outer end of which is connected to the bore 32 .
The inner end of said head 41 may define a stop that engages a surface at the inner end of said head 41 to determine the relative retracted position of said two pistons 22, 23; The actuating barrel assembly according to claim 1, characterized in that the actuating barrel assembly is adapted to abut against the metal 42. 5. said spring-loaded catch 42 has a compression spring 43 held in a partially restrained state by a cage 46;
Claim characterized in that a radial flange 45 at the inner end of the cage 46 forms an abutment 48 that engages the head 41 of the regulator member 38 when the actuating barrel is actuated. The actuating barrel assembly according to item 4 in the range.