JPH0531298Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention provides a gap between the rotor and the friction pad in an air brake (air disc or air S-cam drum) to maintain a constant amount of clearance during non-braking. This invention relates to an automatic adjustment device.

[Prior Art] In general, air brakes were developed as disc brakes, which were mostly hydraulically actuated, began to be used in large vehicles such as trucks. There are two types of push rods, one type which uses air supplied to the air chamber to push up the push rod and rotates the shaft coming out of the caliper, which rotates the power screw built into the caliper to obtain the pressing force on the piston pad. A type is known in which a wedge mechanism is provided at the tip and the pad pressing force piston is moved by the pushing and spreading force of the wedge mechanism.

By the way, even in such an air disc brake, as is known in known hydraulically operated disc brakes, etc., as the lining wear of the friction pads progresses, the gap between the rotor and the friction pads during non-braking occurs. If the increase in space is left unaddressed, it will cause undesirable problems in the brake system, such as a delay in the initial brake operation or an increase in the stroke of the drive part of the brake drive mechanism (specifically, the air chamber in the case of air disc brakes). It will appear as.

Therefore, the present inventor has developed and proposed an automatic adjustment device adapted to such air brakes.

This is based on the following idea. For example, in a power screw type air disc brake, the pad-pressing piston is slidably fitted into the caliper cylinder without being able to rotate around the axis, and the power screw, which is threaded into the piston, is rotated. Therefore, the power screw is relatively screwed in and out, and the power screw is provided so that it cannot move in the axial direction, so that the piston can move forward and backward, and the rotation of the power screw ( In other words, the rotation that causes the piston to relatively screw forward and backward (hereinafter referred to as screw-out rotation and screw-in rotation) is the rear end that protrudes from the caliper of the power screw (the front end that screws into the piston). This is achieved by reciprocating an arm connected to extend in the radial direction from the opposite side (opposite side) via a push rod that reciprocates by driving an air chamber.

Therefore, in an air disc brake with such a configuration, as the lining wear of the friction pad progresses, the piston rest position (return position when the brake is released) is moved forward and repositioned toward the rotor side as necessary, while It is desirable that the range of reciprocating motion of the air chamber, the arm, and the arm be kept constant regardless of the adjustment of the piston position.

Therefore, we installed an intermittent drive mechanism in the part that transmits the swing of the arm as the rotation of the power screw.
When the amount of swing of the arm when the brake is applied exceeds a predetermined small constant amount, the amount of rotation of the power screw generated in conjunction with this is superimposed on the amount of swing of the arm and another rotating element. On the other hand, the return rotation of the power screw is increased by
This is limited to only the return swing of the arm, thereby reducing the amount of backward movement of the piston relative to the power screw, making it possible to reposition the piston forward toward the rotor.

Incidentally, such an automatic adjustment device is the same in the case of the camshaft rotation drive mechanism of the existing air S-mud drum brake.

Specifically, the intermittent drive type mechanism, ie, the automatic adjustment device, includes a worm which is normally maintained in a non-rotating state within the arm, and an adjusting gear which is integrally rotatably engaged with the worm. , an adjuster steering rod which is disposed to be able to reciprocate substantially in the circumferential direction of the outer peripheral tooth portion of the adjuster steering gear, and which engages the adjuster steering gear when the arm reciprocation exceeds a certain value; The worm is engaged with a worm wheel that is pivoted on the power screw shaft or the operating cam shaft, and normally only the swinging motion of the arm is transmitted to the power screw through the engagement between the worm and the worm wheel, and the swinging motion of the arm is transmitted to the power screw through the engagement between the worm and the worm wheel. When the movement exceeds a certain amount, it is possible to consider a system in which the rotation of the adjusting gear is superimposed on the rotation of the power screw based on the swinging of the arm.

[Problems to be solved by the invention] By the way, during such an automatic adjustment device, when assembling the device or replacing the friction pad, it is necessary to manually operate the adjustment device and move the power screw in the forward direction at will. It is necessary to rotate the worm or to rotate it in the reverse direction, and for this purpose, the engagement between the worm and the adjusting gear can be released at will.

However, this disengagement between the worm and the adjuster steering gear may be replaced by other means as long as it does not interfere with the rotation of the worm alone, and from this perspective, the present invention Rather than disengaging the gear, the rotation prevention property of the adjuster steering gear when the worm manual rotates is released in relation to the adjuster steering rod, thereby simplifying the mechanism and facilitating operation. It is something.

[Means for Solving the Problems] Therefore, the gist of the present invention to achieve the above object is to provide a reciprocating oscillation system that rotates the power screw shaft of a disc brake or the operating camshaft of a drum brake around the axis. A worm having a movable arm and normally maintained in a non-rotating state by the arm, an adjuster steering gear that is integrally rotatably engaged with the worm, and a gear approximately around the periphery of the outer peripheral teeth of the adjuster steering gear. The worm is mounted on the power screw shaft or the actuating cam shaft, and has a built-in adjuster steering key that is arranged so as to be able to reciprocate in the direction, and that engages the adjuster steering gear when the forward movement of the arm exceeds a certain value. In the air brake automatic gap adjustment device that transmits rotational force by meshing with a worm wheel, the adjusting key is disengaged from the adjusting gear when the arm is at an initial position and stationary. An automatic gap adjustment device for an air brake, characterized in that the air brake gap is provided in such a manner that

[Example] The present invention will be described below based on an example shown in the drawings.

In the figure, 1 is a rotor, 2 is a fixed support (hereinafter referred to as a support) fixedly installed to straddle a part of the edge of the rotor, and arms that straddle the rotor are placed at two positions spaced apart in the circumferential direction of the rotor. Part 3,
3.

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 denote 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 rotor axial direction.

Reference numeral 10 denotes a cylinder formed on one side portion 5 of the caliper 4, into which a cylindrical pad pressing piston 11 is slidably fitted. A threaded portion 12 is formed on the inner cylindrical portion of this piston 11, which is threadedly engaged with the front end of a power screw 13. The power screw 13 is fitted through a through cylinder 18 of a housing 17 which is bolted and fixed to the rear portion (the side opposite the rotor) of the cylinder 10 of the caliper leg portion 5, and its front end is threadedly engaged with the threaded portion 12 of the piston 11.
A large diameter flange 15 is formed at the axial middle portion thereof so as to be engaged with the housing 17 via a thrust bearing 19 so as to support the axial force. Further, a rear end 16 is formed at the rear end 17 which penetrates the cylinder 18 of the housing 17 and is extended to the outside.
An arm drive mechanism including an arm 20 connected to the push rod of the air shunt is connected to the air shunt.
Reference numeral 2 denotes a bracket which supports an air chamber which will be described later, and 23 denotes a load distribution plate which engages with the friction pad 8 to prevent the pad pressing piston 11 from rotating.

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.

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 squeezing pressure.

Next, referring to the automatic adjustment device built into the arm 20, this includes the worm wheel 28 (spline engaged with the rear end 16 of the power screw, and a worm gear is formed on the outer periphery). It consists of a rotational force transmission part as an engaging part of the worm 29, and an intermittent drive mechanism part that rotates the worm 29 intermittently for adjustment, and the former is referred to as part A and the latter as part B. The relationship between the two is as follows. 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 2.
9. 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, if the arm 20 swings in a substantially constant reciprocating motion, if the worm 29 is not rotated around its axis, the power screw will also rotate by a certain amount, causing the piston to move to a predetermined position. The piston will move forward and backward, but if the worm 29 is properly rotated around its axis and this occurs only when the brake is applied, the piston will move forward and backward, even though the arm 20 swings back and forth equally. They 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 time adjustment.

When the amount of rocking of the arm 20 increases as the lining wear of the friction pad progresses, the portion B is sampled and attached to the worm shaft 29a.
In the example shown in Fig. 3, when the swing of the arm 20 is a predetermined constant value (interval = unadjusted swing amount) when the brake is applied, the worm is activated. 29 does not occur, and the swing of the arm 20 exceeds a certain value.
When λ is required, the worm 29 is rotated by this λ, and therefore the amount of advance generated in the piston 11 through the power screw becomes correspondingly larger. Since the worm 29 does not rotate during the return swing of the rotor 20, the piston 11 moves less backward during the λ period, and as a result, the piston 11 is repositioned in the direction of the rotor 1, that is, the interval is automatically adjusted. It is.

During this time, the specific structure for automatic adjustment is a support hole 20 formed in the arm 20 with a worm shaft 29a projecting in both directions of the axis of the worm 29.
a and 20b, and a biasing spring 25 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 is attached to the other end of the worm shaft 29a. A gear 24 is arranged to be connected to the worm shaft 29a through the worm shaft 29a, and the gear 24 is intermittently fed by one tooth by a one-tooth feeding mechanism to rotate the worm 29.

In this one-tooth feed mechanism, a clevis 27 at the tip of a push rod 26 extending from an air chamber (not shown) attached to a bracket 22 is connected to an arm 2.
It is pivotally connected to the swinging tip of the arm 20 by a pin 27a, and is also pivotally connected to the adjusting rod 30 for rotating the gear 24 by a pin 27b, and as the arm 20 swings, the adjusting rod This mechanism rotates the gear 24 when the gear 30 advances and retreats and exceeds a predetermined amount.

Worm 29 of arm 20 and worm shaft 2
The shaft hole for accommodating the worm shaft 2
Stepped holes 20b, 2 are formed so as to have a stepped larger diameter in sequence from the support hole 20a to which one end side of 9a is slidably fitted.
0c, 20d, and the maximum diameter hole 20
d (right end in FIG. 3) is threaded, the intermediate stepped hole 20b serves as a worm housing, and the stepped hole 20c serves as a housing for the clutch and gear of the intermittent drive mechanism.

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 20b, and is provided with a seal ring 32, so that the worm housing portion ( Part A) and the housing part for the intermittent drive mechanism (Part B) are hermetically isolated.

Further, the clutch mechanism C includes a cone portion 24a formed on the adjusting gear 24 and a worm shaft 2.
The clutch portion is normally kept in the connected state by the biasing spring 25 that presses the worm shaft 29a.
When the piston forward reaction force is transmitted from the worm wheel 28 as a force in the counterclockwise direction in FIG. do.

Next, the mechanism for rotating the adjuster steering gear 24 will be explained. The adjuster steering key 33 that meshes with the outer peripheral teeth of the adjuster steering gear 24 is assembled to a key holding member 34 as shown in FIG. This key holding member 3
4 is held by a return spring 35 to a stopper 36 which normally also serves as a retainer, and is provided so as to move downward in FIG. 5 when receiving the pressing force of the adjusting rod 30. As a result, the key holding member 34
When the adjuster steering key 33 is moved downward in FIG. 5 through the arrow, the adjuster steering gear 24 is provided to be rotated in the clockwise direction in FIG. In addition, 37 is a housing hole portion formed in the arm 20 for housing the adjuster steering key 33, etc.;
8 is boots.

In addition, the adjustment rod 3 shown in the figure
The distance _δ1 between the adjusting gear 20 and the key holding member 34 during non-operation is the distance δ1 between the adjusting gear 20 and the key holding member 34 when the arm 20 swings a certain amount (corresponding to the above-mentioned).
It defines the range of "from movement" that does not result in rotation of 4.

Note that 39 is a plug that also serves as a receiver for the biasing spring 25, and 40 is a plug that has a penetrating portion for the worm shaft 29a, and these plugs seal the accommodating portion for the worm and the like from the outside air.

With the above configuration, the clevis 2 is inserted through the push rod 26 by the operation of the air chamber (not shown).
7 is moved in the direction of FIG. 3A, the arm 20
is the third centering on the rear end 16 of the power screw.
Swings clockwise in the figure.

The swinging of the arm 20 rotates the power screw 13, causing the piston 11 to move forward, pressing the friction pad 8 against the rotor 1, and further pushing the friction pad 9 against the rotor 1 by the reaction claw 6 based on the reaction force. This gives us a sense of pressure.

At this time, under normal conditions (rotation of arm 20 is below)
In this case, the worm 29 is in a non-rotating state. That is, the adjusting key 33 is in a state in which it is not pressed by the adjusting rod 30 (ie, the adjusting rod 30 "moves" within the range of _δ1 ). Further, when the wear of the lining of the friction pad progresses, the amount of swinging of the arm 20 necessary for brake operation will be exceeded, and therefore the adjusting rod 30 will press down the adjusting key 33.
Rotation occurs in the adjusting gear 24. This causes the worm wheel 28 to rotate as the worm 29 rotates, and is superimposed on the rotation of the worm wheel 28 based on the swinging of the arm 20. On the other hand, when the brake is released, the adjusting gear 24 does not rotate because the adjusting key 33 simply slides on the gear teeth. Therefore, the return rotation of the worm wheel 28 is only the return swing of the arm 20, which causes the piston 11 to rotate. The distance adjustment is achieved by making the amount of backward movement smaller than the amount of forward movement.

The feature of this example is that, as shown in FIG. 6, the tip of the claw of the adjusting key 33 is set in a spaced relationship with the outer tooth portion 24a of the adjusting gear 24 when it is in the inactive, resting position. It's what I did. To explain this with reference to FIG. 6, if the diameter of the tip of the adjuster steering gear 24 is R, then the position of the tip of the claw of the adjuster steering key 33 when it is at rest is at R + γ (γ is a slight amount). Consists of.

In this way, the adjuster steering gear 24 can be rotated independently of the adjuster steering key 33 when the brake is not applied. Therefore, if the worm shaft 29a is manually rotated, the clutch mechanism C remains connected. This allows the piston 11 to rotate, making it possible to easily adjust the position of the piston 11 when replacing the pad.

Note that by specifying the rest position of the adjuster steering key 33 described above, by the time it starts rotating the adjuster steering gear 24, δ ₂ shown in FIG.
A range of "movement from" will occur. Therefore, in relation to the above-mentioned range of "from-movement" δ ₁ between the adjusting rod 30 and the key holding member 34, the actual unadjusted swing amount between the arm 20 in this example is = δ ₁ +δ ₂ .

[Effects of the invention] As described above, the air brake automatic adjustment device of the present invention not only automatically adjusts the distance between the rotor and the friction pad during brake operation, but also eliminates friction pad replacement work. The piston position can be easily adjusted at different times, and its practical benefits are great.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of the air disc brake, Figure 2 is a plan view including a partial section, Figure 3 is a longitudinal sectional view of the automatic adjustment device, and Figure 4 is a side view of the same.
FIG. 5 is a sectional view of the intermittent drive mechanism portion, and FIG. 6 is a diagram showing the relationship between the adjusting gear and the adjusting key. 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 pad, 10...Cylinder, 11...Piston, 12...Thread part, 13...Power screw, 14...Thread part, 15...Large diameter flange part,
16... Rear end of power screw, 17... Housing, 18... Cylinder, 19... Thrust bearing, 20... Arm, 20a, 20b... Support hole, 20c, 20d... Stepped hole, 21... Inner space, 23... Road taste distribution plate, 24... Asia steering gear (gear),
24a... Teeth, 25... Biasing spring, 26... Push rod, 27... Clevis, 27a, 27
b...Pin, 29...Worm, 29a...Worm shaft, 29b...Large diameter flange, 29c...
Cone part, 30...Asia stain rod, 3
2...Seal ring, 33...Adjustment key, 34...Key holding member, 35...Return spring, 36...Stopper, 37...Accommodating hole portion, 38...Boot, 39...Further spring, 39 ,4
0...Plug.

Claims (1)

[Scope of utility model registration request] It has a reciprocating swinging arm that rotates the power screw shaft of a disc brake or the operating cam shaft of a drum brake, and a worm that is normally maintained in a non-rotating state on the arm, and that can rotate integrally with the worm. An adjusting gear that engages, and an adjusting gear that is arranged so as to be able to reciprocate approximately in the circumferential direction of the outer peripheral teeth of the adjusting gear, and that engages the adjusting gear when the forward movement of the arm exceeds a certain value. In the air brake automatic gap adjustment device, the air brake gap automatic adjustment device has a built-in key, and transmits rotational force by meshing the worm with a worm wheel pivotally attached to the power screw shaft or the operating cam shaft. An automatic gap adjustment device for an air brake, characterized in that the arm is disposed in such a way that when the arm is in an initial stationary state, the arm is engaged with the adjusting gear at a distance.