JPH0151702B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an auto-adjuster mechanism for a parking disc brake.

Disc brakes have better heat dissipation performance than drum brakes, but incorporating a parking mechanism complicates the structure, and with conventional auto-adjuster mechanisms that use clutch springs, the tension of the clutch spring and the adjustment of the sleeve nut It was necessary to select an appropriate value for the tightness of the staying screw, and there was a risk that the auto-adjuster mechanism would not operate properly if foreign matter was caught between the clutch spring and the sleeve nut.

The present invention provides an adjuster mechanism for a parking disc brake that is easy to manufacture and assemble by using a permanent magnet instead of a clutch spring.

The present invention will be specifically described below with reference to drawings showing embodiments.

In the figure, 1 is a caliper of a floating caliper type disc brake, and a hollow piston 2 is fitted into a cylinder 1b of a rear arm 1a of the caliper 1. The inner pad 3 that comes into contact with the front surface of the hollow piston 2 is connected to the protrusions 4a, 4a of the back metal 4.
are engaged with the engagement grooves 2a, 2a of the hollow piston 2 to restrain rotation of the piston 2. An outer pad 5 is in contact with the forearm 1c of the caliper 1 at its back metal 6. Further, in the rear arm 1a of the caliper, there is a toggle consisting of a cam part 10 which is inserted into the rear arm 1a of the adjuster steering screw 7 while keeping it oil-tight with a seal 8, and is integrated with a link 9 and a parking lever (not shown). It is connected to a shaped parking mechanism. The tip of the adjusting screw 7 is formed with a threaded rod portion 7a having a multi-thread thread. Reference numeral 11 denotes a sleeve nut which is screwed into the threaded rod portion 7a, and has a pin 12 planted at its front end. Reference numeral 13 denotes a holder mounted on the sleeve nut 11, and its outer shape includes a cone portion 13a at the tip, a large diameter portion 13b connected to the cone portion 13a, and a small diameter portion 13d connected via an outer annular side surface 13c.
The inner peripheral surface thereof includes a through hole 13a into which the adjusting screw 7 at the tip is loosely fitted, an inner annular side surface 13f, and a large diameter hole 13g in which the sleeve nut 11 is housed. The sleeve nut 11 is loosely inserted into the large diameter hole 13g, and the pin 12 is loosely inserted into the engagement hole 13h formed in the holder 13, so that the sleeve nut 11 moves relative to the holder 13 only in its axial direction. is allowed. Reference numeral 14 denotes a snap ring which is attached to the inner wall of the large diameter hole 13g of the holder, and movement of the sleeve nut 11 relative to the holder 13 in the axial direction is regulated by the snap ring 14 and the inner annular side surface 13f. The hollow piston 2 is mounted on the holder 13, and the cone portion 13a of the holder is connected to the conical hole 2 at the front of the hollow piston 2.
Make surface contact with b. Two annular permanent magnets 16, one on the holder 13 side and the other on the snap spring 15 side, are placed between the outer annular side surface 13c of the holder 13 and the snap ring 15 attached to the inner peripheral surface of the hollow piston 2.
17 are arranged with the same polarity facing each other. Therefore, in the non-braking state, the holder 13 is moved by the repulsive force of both magnets 16 and 17 into the conical hole 2b of the piston.
is biased so as to come into contact with. Therefore, the sleeve nut 11 and the snap spring 14 have a gap δ. In the conventional disc brake with parking, a bearing and a clutch spring are interposed between the outer annular side surface 13c of the holder 13 and the snap spring 15, but the present invention has a simple structure and is easy to manufacture and assemble. That is, if the holder 13 and the snap ring 15 are made of a magnetic material such as iron, the two magnets 16 and 17 will be attracted and locked to the holder 13 and the snap ring 15, respectively, so there is no need to provide any special fixing means.

In addition, 18 is a disk, 19 is a return spring that returns the sleeve nut 11 and the toggle type parking mechanism to the brake release position, 20 is a dust seal for dustproofing, and 21 is a rubber cover to prevent the intrusion of rainwater, etc. 22 is a spring that holds the link 9.

Next, the operation will be explained. When pressurized oil is introduced from the outside into the cylinder 1b of the caliper during service brake, the hollow piston 2 strokes together with the holder 13, and when the inner pad 3 slides against the disk 18, the caliper 1 receives the reaction force and floats to the outer pad 5. The pads 3 and 5 slide against the disc 18 and press the disc 18 with both pads 3 and 5 to generate braking force. At this time, if the amount of wear on both pads 3 and 5 is within the allowable range, the amount of movement of the holder 13 with respect to the sleeve nut 11 is within the gap δ which is the predetermined amount of relative movement of the holder 13. If the amount of wear on both pads 3 and 5 exceeds the allowable range, the snap spring 14 will come into contact with the sleeve nut 11 during service braking and the cone portion 13a of the holder 13 will be damaged.
A gap is created between the conical hole 2b at the front of the hollow piston 2 and the conical hole 2b at the front of the hollow piston 2. Then, since the magnet 16 receives the repulsive force of the magnet 17, it presses the holder 13 in the direction of filling the gap, that is, in the direction of actuation of the piston 2, and moves the sleeve nut 11 and holder 13 against the adjusting screw 7. Screw it out to perform the adjusting action.

As explained above, according to the present invention, in a floating caliper type disc brake, the magnets are arranged on the holder side and the piston side with the same polarity facing each other. There is no need for the bearings that were used, and the structure of the adjuster mechanism is simplified. In particular, the two magnets that are the component parts do not require strict dimensions and precision, making manufacturing and assembly easier.
Furthermore, the reliability of the adjustment mechanism is improved. Furthermore, since the repulsive force between the magnets is inversely proportional to the square of the magnet gap, the adjusting force will attenuate as the two magnets move apart, so there will be no problem of unreasonable force acting on each component of the adjusting mechanism. It is suitable as

[Brief explanation of drawings]

The drawing is a longitudinal sectional view of a disc brake with parking according to the present invention. 1... Caliper, 1a... Caliper rear arm, 1c... Caliper forearm, 2... Piston, 2b... Conical hole of piston, 3... Inner pad, 5... Outer pad, 7... Asia steering screw, 7a... Spiral rod, 9... Link, DESCRIPTION OF SYMBOLS 10... Cam part, 11... Sleeve nut, 12... Pin, 13... Holder, 13a... Cone part of holder, 13c... Outer annular side surface of holder, 14... Snap ring, 15... Snap ring, 16, 17... Permanent magnet, 18... disc.

Claims (1)

[Claims] 1. An adjuster steering screw that has a threaded rod at its tip and whose base end passes through the rear arm of the caliper and connects to the toggle parking mechanism, a sleeve nut that is screwed into the threaded rod with a multi-thread screw, and a sleeve. a holder that is allowed to move by a predetermined amount only in the axial direction with respect to the nut and is crowned and has a cone portion at the tip;
In a floating caliper type disc brake, which has a conical hole that is mounted on the holder and fits with the cone of the holder, and a piston that fits into the rear arm of the caliper and abuts the inner pad at the tip, the holder side and the hollow An auto-adjuster mechanism for disc brakes characterized by a magnet arranged with the same polarity facing the piston side.