JP3003024B2 - Automatic gap adjusting device between brake drum and brake shoe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic gap adjusting device between a brake drum and a brake shoe, and more particularly to an automatic gap adjusting device between a brake drum and a brake shoe for preventing a malfunction due to an idle movement of an auto adjuster shaft. Things.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional apparatus for automatically adjusting the gap between a brake drum and a brake shoe.
A hole 3 formed at the left end formed in the hole 3 is fitted into the hole 2, moves in the axial direction in the body 1, and presses a brake shoe (not shown) at the left end.
Is a detent for locking the piston 3 acting in engagement with a brake shoe (not shown), 5 is a right-hand screw hole formed in the center of the piston 3 and opened at the right end thereof, and 6 is a right-hand screw hole 5 An adjuster shaft 7 for automatically adjusting a gap between a brake drum (not shown) and a brake shoe (not shown) screwed to a constant value is formed at the center of the right end of the adjuster shaft 6. A hole 8 opened in the right end face thereof is inserted into the hole 7 through a spring 9, and a locator whose right end is in contact with the center of the bottom surface of the hole 2 of the body 1, and 10 is the adjuster shaft 6. The hole formed in the radial direction at the left end of the hole 11 is the hole 1
The spring for preventing free movement, which is disposed in the inner portion 0 and protrudes radially outward from the outer peripheral surface of the adjuster shaft 6 and is in contact with the inner peripheral surface of the right screw hole 5 of the piston 3, the brake spring 12 is used for brake operation. A hydraulic passage for pressing the piston 3 leftward in the axial direction, 13 is a dustproof boot, 14 is a packing inserted between the outer peripheral surface of the piston 3 and the inner wall of the hole 2 of the body 1, and 15 is Right-handed bevels 16 formed on the outer periphery of the right end of the adjuster shaft 6 at intervals from each other, and a turn 16 which is in contact with the bottom slope of the hole 2 of the body 1 so as to mesh with the bevel 15. A moving ring 17 is a spring provided on the adjuster shaft 6 so as to constantly suppress the rotating ring 16 to the right. Deterrence for retaining Ring, 19 is a gap manual adjustment gear for allowing move it by rotating the piston 3 manually to the left relative axial to the adjuster earth shaft 6.

[0003] In such a conventional automatic adjusting device for the gap between the brake drum and the brake shoe, when the gap between the brake drum and the brake shoe becomes larger than a predetermined value due to the wear of the brake shoe, the gap is set as follows. Adjusted automatically.

[0004] 1. The piston 3 and the adjuster shaft 6 are moved leftward in the axial direction by the hydraulic pressure applied through the hydraulic passage 12 for the brake operation. If the gap is within a predetermined range, the skew tooth 1 can be moved by the leftward movement.
5 and pivot ring 16 do not engage with each other.

[0005] 2. If the gap becomes larger than a predetermined range, the corresponding piston 3 and adjuster shaft 6
The bevel teeth 15 are engaged with the rotation ring 16 by the axial movement of. Further, when the gap is large, the rotation ring 16 moves to the left together with the adjuster shaft 6 in a state of being in contact with the restraining ring 18.

When the brake is released and the piston 3 or the like is pushed to the right by a return spring (not shown) of the brake shoe, first, the rotating ring 16 is fixed to the bottom slope of the hole of the body 1. Next, the fixed rotating ring 16 causes the bevel 15 of the adjuster shaft 6 to rotate counterclockwise.

Accordingly, the piston 3 screwed to the adjuster shaft 6 moves leftward in the axial direction relatively to the adjuster shaft 6 without rotating by the action of the rotation stopper 4, and the piston 3 moves in the leftward direction. The gap is adjusted according to the amount of rotation of the rotating ring 16 rotated during the movement.

[0008]

However, in the above-described conventional automatic adjusting device for the gap between the brake drum and the brake shoe, not only the structure is complicated, but also the vibration of the vehicle during running and the vibration (squeal) during braking. As a result, the adjuster shaft 6 rotates clockwise relative to the piston 3 against the force of the spring 11 for preventing movement, and as a result, the piston 3 moves rightward in the axial direction relative to the adjuster shaft 6. However, the gap may be larger than a predetermined value.

The present invention has been made to eliminate the above disadvantages.

[0010]

An automatic gap adjusting device between a brake drum and a brake shoe according to the present invention is axially movable within a body of a wheel cylinder for adjusting a gap between a brake drum and a brake shoe. A piston for adjusting the gap by rotating the adjuster shaft in one direction relative to the piston when the adjuster shaft moves in the axial direction; and adjusting the gap by adjusting the gap. The floating prevention means comprises a floating prevention spring, a hole formed in the adjuster shaft for fitting an outer periphery of one end of the spring, and a floating prevention spring formed in the other end of the spring. The body comprises an axial extension and an elongated hole formed in the body in the axial direction so that the extension can be inserted.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, as shown in FIGS. 1 and 2, a large-diameter hole 20 surrounding the hole 7 at the center of the right end of the adjuster shaft 6 is formed.
The right end 22 of the right-handed play prevention spring 21 having an outer diameter slightly larger than the inner diameter of the body 1 is fitted, and the right end 22 is extended in the axial direction. It is inserted into the hole 23.

Since the apparatus for automatically adjusting the gap between the brake drum and the brake shoe according to the present invention is configured as described above, the adjuster shaft 6 is turned counterclockwise by the action of the bevel teeth 15 and the rotating ring 16 for adjusting the gap. In this case, the floating movement spring 21 is also rotated counterclockwise, and the outer diameter of the floating movement preventing spring 21 decreases, so that the floating movement preventing spring 21 rotates the adjuster shaft 6 counterclockwise. If the adjuster shaft 6 moves clockwise due to vibration of the vehicle during running or vibration during brake operation, the left end of the adjuster shaft 6 is fitted into the hole 20 of the adjuster shaft 6. The movement preventing spring 21 receives a clockwise force, which acts on the spring 21 so as to increase the outer diameter thereof. Right around the rotation is to be prevented friction of the adjuster shaft 6 to become large.

The floating movement preventing spring 21 has a function of constantly pressing the adjuster shaft 6 to the left, and even if the floating movement preventing spring 21 moves to the left together with the adjuster shaft 6, the right end thereof can be used. 2
The length of the right end 22 is determined so that the second end 2 does not fall out of the long hole 23 of the bottom surface of the hole 2 of the body 1.

[0015]

As described above, according to the apparatus for automatically adjusting the gap between the brake drum and the brake shoe according to the present invention, the conventional radial hole 10 and the spring 1 for preventing movement are used.
1, the locator 8 and the spring 9 can be omitted, so that the structure can be greatly simplified, and there is a great advantage that malfunction of gap adjustment due to vibration of the vehicle or the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a device for automatically adjusting a gap between a brake drum and a brake shoe according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of the automatic gap adjusting device shown in FIG.

FIG. 3 is a cross-sectional view of a conventional apparatus for automatically adjusting a gap between a brake drum and a brake shoe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 hole 3 Piston 4 Detent 5 Right screw hole 6 Adjuster shaft 7 Hole 8 Locator 9 Spring 10 Hole 11 Spring for preventing movement 12 Hydraulic passage 13 Boot 14 Packing 15 Bevel 16 Rotation ring 17 Spring 18 Suppression ring 19 Gap manual adjustment gear 20 Hole 21 Idling prevention spring 22 Right end 23 Slot

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-40027 (JP, A) JP-A-54-111583 (JP, U) JP-A-3-121241 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) F16D 65/56

Claims (1)

(57) [Claims] 1. A piston which is movable in an axial direction within a body of a wheel cylinder for adjusting a gap between a brake drum and a brake shoe, an adjuster shaft screwed to the piston, and the adjuster shaft is arranged in an axial direction. And a means for rotating the piston relative to the piston in one direction to adjust the gap, and a means for preventing movement of the adjuster shaft in the other direction. A hole formed in the adjuster shaft for fitting the outer periphery of one end of the spring; an axial extension formed in the other end of the spring; and an axial extension in the body so that the extension is inserted. An automatic gap adjusting device between a brake drum and a brake shoe, wherein the automatic gap adjusting device comprises an elongated hole formed.