JPS6326583Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic gap adjustment device that maintains a constant gap amount between rotor friction pads during non-braking in an air brake (air disc or air S-cam drum).

Recently, air disc brakes (or air S-cam drum brakes:
(omitted below), the screw position relationship between the power screw rotatably driven by an air chamber etc. and the threaded piston (pad pressing piston) that screws into the power screw is determined as the lining wear of the friction pad progresses. An automatic gap adjustment device has been proposed in which the gap is adjusted by changing the piston and gradually repositioning the piston closer to the friction pad side, that is, the rotor side.

The present invention has been made for the purpose of simplifying the structure and facilitating processing of such an automatic gap adjustment device.

The overall outline of an example of an air disc brake to which the present invention is applied will now be explained with reference to Figs. 1 to 3. In the figures, 1 indicates a rotor;
2 is a fixed support (hereinafter referred to as "support") fixedly installed so as to straddle a part of the edge of the rotor, and is provided with arm parts 3, 3 that straddle the rotor at two positions spaced apart in the circumferential direction of the rotor. is formed.

4 is an arm 3 that supports the edge of this rotor 1;
It is a caliper arranged so as to straddle between 3,
A leg 5 on one side of the rotor 1 incorporates a pad pressing mechanism, and a leg 6 on the other side of the rotor 1 forms a reaction claw.

The caliper 4 is supported so as to be movable in the axial direction of the rotor with respect to the support 2 via pin slide type sliding support devices 7, 7 each including a slide pin attached to both sides in the circumferential direction of the rotor.

Reference numerals 8 and 9 designate a pair of friction pads that are arranged to face each other with the rotor 1 in between, and are provided so that the torque during braking is directly received by the arm portions 3 and 3 on both sides of the support 2. The side friction pad 8 is supported by the support 2, and the outer side friction pad 9 is supported by a slide pin so as to be slidable in the axial direction of the rotor.

A cylinder 10 is formed on one side leg 5 of the caliper 4, and a cylindrical pad pressing piston 11 is slidably fitted thereto. A threaded portion 12 is formed in the inner cylindrical portion of the piston 11 to be screwed into the front end of the power screw 13. The power screw 13 is slidably fitted through a through cylinder 18 of a housing 17 bolted to the rear part of the cylinder 10 of the caliper leg 5 (on the opposite side from the rotor), and the piston 11 is screwed into the front end of the housing 17. Part 12
A large-diameter flange 15 is formed in the axially intermediate portion of the housing 17 so that the axial force can be supported by the housing 17 through a thrust bearing 19. Rear end 16 penetrated and inserted to the outside
An arm drive mechanism including an arm 20 connected to the push rod of the air chamber is connected to.

The connection structure between the rear end of the power screw 13 and the arm 20 extending in its radial direction is used to transmit the movement of the intermittent drive mechanism for adjustment, which will be described later, to the power screw in addition to transmitting arm swing. , a worm 29 (see FIG. 3) built into the arm 20 and normally maintained in a non-rotating state, and a worm wheel 28 (spline engagement) that is pivoted to the rear end 16 of the power screw 13 (see FIG. 3). (See Figure 3)
The swinging motion of the arm is transmitted as rotation of the power screw through the engaging portion.

The cylinder 18 of the housing 17 is slidably connected to the power screw 13 via a bush. Note that the inner space 21 of the cylinder 10 that accommodates the piston 11 is filled with lubricant (grease). 22 is a bracket for mounting the air chamber.

Reference numeral 23 denotes a load distribution plate, which is disposed so as to be engaged with the distal end surface of the piston 11 in a convex-concave manner, and inserted into the back surface of the inner friction pad 8 in a concave-convex manner to prevent the piston 11 from rotating. This is to effectively transmit the pressing force of the piston 11 to the friction pad 8.

With such a configuration, when the arm 20 swings (swings when the brake is applied), the power screw 13 is correspondingly screwed out and rotated in a fixed position (without axial movement), so that the piston 11
moves forward in a non-rotating manner (relatively to the power screw, it rotates forward) to press the friction pad 8 against the rotor 1.

Therefore, the caliper 4 slides to the right in FIG. 1 due to the reaction force while being supported by the sliding support devices 7, 7, and presses the outer side friction pads 9 against the rotor 1. Braking force is generated by clamping pressure.

Next, we will discuss the automatic gap adjustment device built into the arm 20. This device consists of the aforementioned worm wheel 28 (spline engaged with the rear end 16 of the power screw and having a worm gear formed on the outer periphery), It consists of a rotational force transmission part that engages with the worm 29, and an intermittent drive mechanism part that rotates the worm 29 intermittently for gap adjustment.If the former is part A and the latter is part B, the two parts are as follows. We have a similar relationship. That is, the worm shaft 29a that is integrally attached to the worm 29 is
Normally, the rotational force for rotation around the axis is not particularly transmitted. Therefore, when the arm 20 swings around the rear end 16 of the power screw, the swing of the arm 20 is caused by the worm 29.
The power is directly transmitted to the power screw via the worm wheel 28.

On the other hand, when rotational force around the axis is applied to the worm shaft 29a separately from the swinging of the arm 20, the resulting rotation of the worm 29 around the axis is transmitted from the worm wheel 28 to the power screw.

In other words, when the swing of the arm 20 is always a substantially constant reciprocating motion, if the worm 29 is not rotated around the axis, the power screw will also rotate by a constant amount, moving the piston back and forth at a predetermined position. However, if the worm 29 is properly rotated around its axis and this occurs only when the brake is applied (or when the brake is released), even though the arm 20 swings back and forth equally, The forward movement and backward movement of the piston do not appear equally; for example, if the amount of backward movement of the piston appears to be smaller than the amount of movement forward, this can be used as a gap adjustment.

The above-mentioned section B is an intermittent drive that applies a predetermined rotational force to the worm shaft 29a by collecting the swing amount of the arm section 20 when it increases as the lining wear of the friction pad progresses. In the example shown in FIG. 3, when the arm 20 swings at a predetermined constant value l during brake operation, the worm 29 does not rotate, and the arm 2
When the oscillation of 0 exceeds a certain value and requires l+λ, the worm 29 is rotated by this amount of λ, and therefore the amount of advance generated in the piston 11 via the power screw is becomes larger by that amount, but since the worm 29 does not rotate when the arm 20 swings back, the piston 11 moves less backward during the λ portion, and as a result, the piston 11 moves back toward the rotor 1. Orientation, or automatic gap adjustment, is performed.

The specific configuration for such automatic gap adjustment is not directly related to the present invention, so it will be briefly explained.
A support hole 20 in which a worm shaft 29a protruding in both directions of the axis of the worm 29 is formed in the arm 20.
A, 20a are slidably supported, and a spring is engaged with one end of the worm shaft 29a to press the worm shaft 29a toward the other end, and a clutch mechanism C,
and the worm shaft 29 via this clutch mechanism.
A gear 24 is disposed intermittently at
The worm 29 is configured to be rotated by being intermittently fed one tooth by a one tooth feeding mechanism.

In this single-tooth feeding mechanism, a clevis 27 at the tip of a push rod 26 extending from an air chamber 25 assembled to a bracket 22 is pivotally connected to an arm 20, and an adjusting rod for rotating the gear 24. 30, the adjusting rod 30 moves forward and backward as the arm 20 swings, and when this exceeds a predetermined amount, the gear 24 is rotated.

Incidentally, by providing the position where the adjusting rod 30 is pivotally connected to the clevis on a side farther from the plunger 26 than the position where the arm 20 is pivotally connected, the gap adjustment operation can be made negative.

By the way, in the automatic gap adjustment device having the above configuration, the worm 29 and the worm shaft 29a incorporated in the arm 20 have a portion A that engages with the worm wheel 28 having an axis that intersects with this axis, and Since the end of the worm shaft is connected to the B part intermittent drive mechanism, as shown in FIG. (Front and rear circular) opening 20b is provided, a worm 29 with a shaft hole is installed in the front part, the worm shaft 29a is inserted and fitted, and the worm wheel 28 is installed in the rear circular part. are doing.

However, in such a configuration, after the worm, the worm shaft, and the worm wheel are assembled, the arm 20 is installed to support the worm wheel and to close the keyhole opening 20b in order to seal this part from the outside air. It is necessary to place elliptical or egg-shaped closing plates 31 on each side of the opening and fix them at several locations (five locations in the illustrated example) using spot welding, etc. (see Figures 4 and 5), and process the opening. This poses a problem in that the work of assembling the closing plate becomes complicated.

Therefore, in the present invention, we have improved the method of assembling the worm and worm shaft of such automatic gap adjustment device, and this is by making it possible to integrate the worm and worm shaft into one body from one direction of the shaft, so that it can be attached to the arm. The opening that needs to be drilled perpendicular to the worm axis should be limited to the worm wheel housing area, and should also support the worm wheel and seal the engagement area between the worm and the worm wheel from the outside air. The supporting structure for this purpose was made extremely simple.

In other words, in the present invention, the worm wheel has a central opening (shaft fitting opening) on its inner circumference that is spline-engaged with the rear end of the power screw, and a diameter that is slightly larger than this central opening at both axial ends. A flange that is provided with a stepped retainer fitting fixation part (a large diameter opening for retainer fitting), and the other inner peripheral edge (cylindrical part) is press-fitted into the fitting fixation part of the worm wheel. An annular retainer having a shape is fixed to both sides of the worm wheel in the axial direction, and the outer peripheral edge (flange)
The worm wheel is slidably engaged with the side wall of the arm to support the worm wheel and prevent it from coming off. The engagement part between the worm and the worm wheel is sealed from the outside air by a seal ring that is attached to the outer periphery of the worm wheel at a position away from the gear part and is attached to the inner periphery of the opening of the arm. .

The present invention will be explained below based on the embodiment shown in FIGS. 6 to 9.
This invention is based on the automatic gap adjustment device having the structure shown in FIG. 3, and the present invention is applied thereto, so common members are given the same reference numerals and their explanations will be omitted.

In this embodiment, the worm 2 of the arm 20
The shaft hole for accommodating the worm shaft 29a and the worm shaft 29a includes stepped holes 20c, 20d, and 20e formed so as to have stepped larger diameters starting from the support hole 20a into which one end of the worm shaft 29a is slidably fitted. The largest diameter hole 20e is threaded, the stepped hole 20c in the middle serves as a housing for the worm 29, and the stepped hole 20d serves as a housing for the clutch and gear of the intermittent drive mechanism. There is.

In this example, a large-diameter flange portion 29b is formed on a part of the worm shaft 29a, and this large-diameter flange portion 29b slides into the stepped hole 20c, and is provided with a seal ring 32, so that the worm housing portion ( A section) and the intermittent drive mechanism accommodating section (B section) are hermetically isolated, and in this respect, as shown in FIGS.
The configuration is different from the one shown in the figure.

According to the configuration of this embodiment, the worm 29 and the worm shaft 29a can be assembled into the arm 20 from one end in the axial direction (right side in the figure). There is no need to form a part for housing the worm (the front part of the keyhole-shaped opening shown in FIGS. 3 and 4) as an arm opening perpendicular to the axis.

The specific structure of the intermittent drive mechanism including the worm shaft 29a is substantially the same as that shown in FIGS. 1 to 3 above.

That is, the adjust key 33 is the ninth
As shown in the figure, it is assembled to a key holding member 34, and this key holding member 34 is attached to a return spring 35.
It is normally locked by a stopper 36 which also serves as a retainer, and is also provided so as to move downward in FIG. 9 when receiving the pressing force of the adjusting rod 30. When the adjusting key 33 is moved downward in FIG. 9 via the key holding member 34, the adjusting gear 24 is rotated clockwise in FIG. In addition, 37 is an adjuster steering key 33 formed on the arm 20.
38 is a boot.

In addition, a cone portion 24a formed on the adjusting gear 24 and a cone portion 29 of the worm shaft 29a.
The clutch mechanism C is constituted by the engagement of c, and normally the clutch portion is kept in a connected state by a disc spring 39 that presses the worm shaft 29c. When transmitted as a clockwise force,
By moving the worm shaft 29a against the disc spring 39, the clutch portion is brought into a disconnected state.

The gap indicated by δ in the figure is a gap that allows movement of the worm shaft 29a in order to disconnect the clutch portion. 40 is a disc spring 39
41 is the worm shaft 29a.
These plugs have a penetrating portion, and these plugs seal the accommodating portion for a worm or the like from the outside air.

The end of the worm shaft 29a that protrudes outside through the plug 41 is provided with a hole 29d for manual rotation of the shaft.A tool can be inserted into the hole 29d to rotate the shaft 29a and the worm. 29
By rotating the power screw 13, you can force the manual to rotate the power screw 13.
It is possible to adjust the position of the piston 11 by rotating the worm 29 while pressing it to perform screw rotation.

42 is a seal ring that airtightly seals the sliding surfaces of the plug 41 and the end of the worm shaft 29a, and this seal ring 42 is connected to the boot 3 described above.
8 and the seal ring 32 to seal the intermittent drive mechanism from the outside air and from the worm-worm wheel engagement portion.

Next, the configuration of the accommodating portion of the worm wheel 28 will be explained. As is already clear from the above description, the worm wheel 28 is bored in the arm 20 so as to be perpendicular to the axis of the worm 29.
Therefore, in this embodiment, as shown in FIGS. 7 and 8, a circular through opening 20b' is formed in the arm 20, and a part of the outer circumference of the worm 29 is inserted into this opening 20b'. At the same time, the worm 29 is engaged with the outer gear portion 28a of the worm wheel 28 which is slidably accommodated in the opening 20b'.

This worm wheel 28 has a gear part 28a on the outer periphery as described above, and this gear part 28
It has a sliding fit that comes into sliding contact with the opening 20b' on both sides in the axial direction of
3 and 43. Further, a spline portion 28b that engages with the rear end 16 of the power screw is formed at the center of the shaft center portion, and retainer fitting portions 28c of a slightly larger diameter are formed on both sides of the spline portion 28b in the axial direction. There is.

44, 44 are retainers for holding the worm wheel 28, and flange parts 44a, 44a formed on the inner circumferential edge of the annular shape are fixed to the fitting part of the worm wheel 28 by press fitting, and the outer periphery of the annular ring is fixed. The peripheral edge is adapted to restrict the worm wheel 28 from being pulled out in the axial direction by engaging with the side wall surface of the arm 20. The retainers 44, 44 rotate together with the worm wheel 28 relative to the arm 20, and the distance between the pair of retainers is set slightly larger than the thickness of the arm 20 so that the rotation occurs smoothly. It is better to configure

Note that 45 is a grease nipple for filling the engagement portion between the worm and the worm wheel with grease.

According to the automatic gap adjustment device configured as described above, its operation is exactly the same as that shown in Figs. 1 to 3, but on the other hand, the work efficiency required during arm processing and assembly is For example, all of the drilled parts on the arm are circular holes, which makes processing and sealing easier, and when installing and holding the worm wheel, the retainer only needs to be mechanically press-fitted. The practical advantage is extremely great, as the engagement part between the worm and the worm wheel and the housing part of the intermittent drive mechanism can be separated from each other by simply assembling a seal ring. It also has the benefit of being effectively sealed from the outside air.

[Brief explanation of drawings]

Figures 1 to 3 show an example of an air disc brake to which the present invention is applied, in which Figure 1 is a longitudinal cross-sectional view of the disc brake, Figure 2 is a plan view including a partial cross section, and Figure 3 is a partial cross-sectional view of the disc brake. 4 is a front view showing the opening shape of the arm, FIG. 5 is a side view of the same, and FIG. 6 is a longitudinal sectional view of the automatic gap adjustment device showing an embodiment of the present invention. FIG. 7 is a front view of the same, FIG. 8 is a partial side sectional view, and FIG. 9 is a partial side sectional view of other parts. DESCRIPTION OF SYMBOLS 1... Rotor, 2... Support, 3... Arm part, 4... Caliper, 5... Leg part, 6... Leg part (reaction claw part), 7... Sliding support device, 8, 9...
Friction part, 10...Cylinder, 11...Piston, 12...Thread part, 13...Power screw, 14...Thread part, 15...Large diameter flange part,
16... Power screw rear end, 17... Housing, 18... Cylinder, 19... Thrust bearing, 20... Arm, 20a... Support hole, 2
0b, 20b'...Opening, 20c, 20d, 20e
...Stepped hole, 21...Inner space, 22...Bracket, 23...Load distribution plate, 24...Adjustment gear (gear),
24a... Cone part, 25... Air chamber, 2
6... Push rod, 27... Clevis, 28
... Worm wheel, 28a ... Gear part, 28
b... Spline engagement part, 28c... Retainer fitting part, 29... Worm, 29a... Worm shaft, 29b... Cone part, 29c... Large diameter flange part, 29d... Hole part, 30... Adjusting rod, 31... plate, 32... seal ring, 33... adjusting key, 34...
Holding member, 35...spring, 36...retainer, 37...accommodating hole, 38...boot, 39...
... disc spring, 40, 41 ... plug, 42 ... seal ring, 43 ... seal ring, 44 ... retainer, 44a ... flange section, 45 ... grease nipple.

Claims (1)

[Scope of utility model registration request] It has an arm drive mechanism that rotates the power screw shaft of a disc brake or the operating cam shaft of a drum brake, and this arm drive mechanism rotates the arm non-rotationally with respect to a worm wheel that is fitted onto the shaft. In an air brake automatic gap adjustment device of the type that incorporates a worm that transmits rocking motion and an intermittent drive mechanism that is operatively connected to the shaft of the worm and drives the worm during gap adjustment, the worm wheel includes: A portion of the worm wheel on both sides in the axial direction of the shaft fitting opening is provided so as to be received and slidably fitted into the through opening formed in the arm and supported by a retainer to prevent it from coming off, and is fitted and pivotally mounted on the shaft. is provided with a large-diameter opening for fitting the retainer, and the retainer has a cylindrical portion that is press-fitted into the large-diameter opening and a collar that is slidably engaged with the arm side wall. Automatic gap adjustment device for air brakes.