CN1150622A - Automatic gap adjuster for hydraulic brake - Google Patents
Automatic gap adjuster for hydraulic brake Download PDFInfo
- Publication number
- CN1150622A CN1150622A CN 95118358 CN95118358A CN1150622A CN 1150622 A CN1150622 A CN 1150622A CN 95118358 CN95118358 CN 95118358 CN 95118358 A CN95118358 A CN 95118358A CN 1150622 A CN1150622 A CN 1150622A
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- China
- Prior art keywords
- brake
- wheel cylinder
- brake shoe
- positioning ring
- end surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- 108700041286 delta Proteins 0.000 description 8
- 239000012530 fluid Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 2
- 241000239290 Araneae Species 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
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- Braking Arrangements (AREA)
Abstract
The automatic gap adjuster for hydraulic brake is characterized by that a positioning ring is placed between the wheel cylinder piston and brake shoe driving piece which are connected in the brake wheel cylinder, and said positioning ring is installed in the brake wheel cylinder in the mode of shrink fit, and its shrink range is that it can allow the positioning ring to axially move under the action of brake hydraulic pressure, and cannot axially shift under the action of reset spring, and under the condition of braking state, between the flange end face of the driving piece and one end face of the positioning ring there is a triangle shaped set gap, and under the condition of non-braking state, between the end face of the wheel cylinder piston and another end face of the positioning ring there is the described triangle shaped set gap.
Description
The present invention relates generally to hydraulic brakes for automobiles, and more particularly to a clearance adjustment device for adjusting the clearance between a brake drum and a brake pad in a hydraulic brake for an automobile. The gap adjusting device is particularly suitable for hydraulic brakes of light automobiles, particularly hydraulic brakes of automobiles such as BJ2020 and BJ2021 with floating brake shoes.
A conventional automotive hydraulic brake is shown in fig. 4, which is only schematically shown to illustrate the operation of the brake and its lash adjustment device. As shown in fig. 4, the conventional hydraulic brake includes a non-rotating brake base plate 41, a brake shoe 44 is supported at one end thereof on the brake base plate 41 so that the brake shoe 44 can swing in an expanding and contracting manner, a brake shoe friction plate 43 is fixed to an outer side of the brake shoe 44, and a gap is formed between the outer side of the brake shoe friction plate 43 and the rotating brake drum 42 in a non-braking state. The other end of the brake shoe 44 abuts a brake shoe pusher 47, which pusher 47 in turn is connected to a wheel cylinder piston 48 in a brake wheel cylinder 49, which wheel cylinder 49 is also fixed to the non-rotating brake spider 41. Brake shoe return spring 46 has one end fixed to brake backing plate 41 and the other end fixed to brake shoe 44. Brake clearance adjustment cam 45 mounted on brake backing plate 41 abuts brake shoes 44 under non-braking conditions and limits the retracted position of brake shoes 44. The conventional brake clearance adjusting device is a cam which can be fastened after rotating. When a driver steps on a brake pedal to perform a braking operation, the brake fluid pressure in the brake wheel cylinder 49 is increased to push the wheel cylinder piston 48 to move, the wheel cylinder piston 48 pushes the end of the brake shoe 44 through the brake shoe pushing piece 47 to overcome the tension of the brake shoe return spring 46 to swing the brake shoe 44, so that the brake shoe friction plate 43 on the brake shoe 44 is abutted against the inner side of the rotating brake drum 42 to generate a braking torque, and when the driver releases the stepping on the brake pedal, the brake shoe 44 is retracted under the action of the brake shoe return spring 46 until the brake shoe is abutted against the brake clearance adjusting cam 45, and at the moment, the clearance delta 1 is still kept between the outer side of the brake shoe friction plate 43 and the inner side of the brake drum 42.
In the conventional brake, after a certain period of use, due to wear of the brake shoe friction plate 43 or other reasons, the braking gap Δ 1 increases, which requires a larger braking stroke of the wheel cylinder piston 48, that is, a larger stroke of the driver for stepping on the brake pedal. This is disadvantageous to the braking effect and even in case of accidents, the braking clearance Δ 1 must be adjusted periodically, and the clearance adjustment of the conventional braking clearance adjustment device is to manually and periodically rotate the braking clearance adjustment cam 45 (for example, clockwise as shown in fig. 4) to change the retracted position of the brake shoe 44 to maintain the original braking clearance Δ 1. Such manual regular adjustment of the gap Δ 1 requires a certain skill and experience, and the operation is very complicated, and in addition, the user often forgets to adjust the gap to cause an accident.
Accordingly, it is an object of the present invention to provide an automatic clearance adjustment mechanism for a hydraulic brake that automatically adjusts the brake clearance during use when the brake clearance is increased without requiring periodic, dedicated manual adjustment.
In order to achieve the above object, the present invention provides an automatic gap adjusting device for a hydraulic brake, the device has a brake wheel cylinder installed on a brake base plate 2, a wheel cylinder piston installed in the brake wheel cylinder, and a brake shoe pushing member abutted against one end of a brake shoe, and is characterized in that a positioning ring is installed between the wheel cylinder piston and the brake shoe pushing member connected in the brake wheel cylinder, the positioning ring is installed in the brake wheel cylinder in an interference fit, the interference is such that the positioning ring can move axially under the action of brake fluid pressure in the brake wheel cylinder, and cannot move axially under the action of elastic force of a brake shoe return spring; and a set gap delta is formed between the flange end surface of the brake shoe pushing piece and one end surface of the positioning ring under the braking state, namely under the condition that the brake shoe friction plate is attached to the brake drum, the set gap delta is formed between the end surface of the wheel cylinder piston and the other end surface of the positioning ring under the non-braking state, and the flange end surface of the brake shoe pushing piece is abutted against one end surface of the positioning ring.
The retaining ring may be cup-shaped with a through hole in the center.
When the brake is applied, the piston end surface of the brake cylinder and the end surface of the positioning ring have a set gap delta, so that the piston of the brake cylinder moves and pushes one end of the brake shoe through the brake shoe pushing piece to open the brake of the brake shoe, and the brake shoe friction plate is abutted with the brake drum to generate brake torque to brake the rotating brake drum. If the clearance between the brake shoe friction plate and the brake drum is increased due to abrasion, the brake shoe friction plate is not attached to the brake drum after the piston of the brake cylinder moves in the axial direction of the clearance delta, and at the moment, under the action of brake fluid pressure in the wheel cylinder, the wheel cylinder piston overcomes the resistance of interference assembly of the positioning ring to push the positioning ring to move continuously until the brake shoe pushing piece pushes the end of the brake shoe to enable the brake shoe friction plate to be attached to the brake drum to implement braking. At the moment, when the braking operation is eliminated, the pressure in the wheel cylinder is reduced, the brake shoe retracts under the action of the brake shoe return spring, the end head of the brake shoe pushes the brake shoe pushing piece and the wheel cylinder piston to retract into the brake cylinder together until the end face of the brake shoe pushing piece abuts against the end face of the positioning ring, and at the moment, the original braking gap is still reserved between the brake shoe friction plate and the brake drum. Thus, the brake clearance is automatically adjusted.
Therefore, the utility model provides an automatic clearance adjustment device need not regularly with manual adjustment braking clearance, as long as the in-process of implementing the braking is adjusted automatically when the braking clearance increases because of wearing and tearing. Since the positioning ring is located between the wheel cylinder piston and the brake shoe urging member which are connected to each other, the gap Δ between the end faces of the positioning ring is not changed regardless of the position of the positioning ring relative to the brake cylinder, so that the brake gap between the brake shoe friction plate and the brake drum is also maintained at the set desired value.
The following describes embodiments of the present invention in detail with reference to the accompanying drawings. Wherein,
fig. 1 is a schematic view of the overall assembly of a hydraulic brake for an automobile, in which an automatic clearance adjustment device according to the present invention is provided;
FIG. 2 is a schematic cross-sectional view of an automatic gap adjustment apparatus; the situation shown is a state in which braking is applied;
FIG. 3 is a schematic cross-sectional view of an automatic gap adjustment apparatus; the condition shown is a non-braking state;
fig. 4 is a schematic view of a prior art brake, showing only one brake shoe for clarity.
Referring to fig. 1, the hydraulic brake for an automobile has a non-rotating backing plate 2, a brake shoe 3 supported at one end thereof on a brake shoe supporter 11 mounted on the backing plate 2, and a brake shoe return spring 5 fixed at one end thereof to the brake shoe 3 and at the other end thereof to the backing plate 2. A brake shoe friction plate 10 is fixedly arranged on the brake shoe 3, and a required brake clearance delta 1 is formed between the outer side of the brake shoe friction plate 10 and the inner side of the rotatable brake drum 1. The non-bearing end of the brake shoe 3 abuts the brake shoe pusher 9. The automatic clearance adjusting device of the brake is provided with a brake wheel cylinder 4 arranged on a brake bottom plate 2, a wheel cylinder piston 6 arranged in the brake wheel cylinder 4 and a brake shoe pushing piece 9, wherein a sealing ring 12 is arranged on the wheel cylinder piston 6, and the automatic clearance adjusting device is characterized in that a positioning ring 8 which is in a cup shape and is provided with a through hole at the center is arranged between the wheel cylinder piston 6 and the brake shoe pushing piece 9 which are connected, the positioning ring 8 is arranged in the brake wheel cylinder 4 in an interference fit manner, the interference of the interference fit can prevent the positioning ring from axially moving under the action of a brake shoe return spring 5, and the positioning ring can axially move under the pressure action of brake fluid in the brake wheel cylinder 4. The bottom thickness of the cup-shaped positioning ring 8 is smaller than the gap distance between the end face of the wheel cylinder piston 6 and the end face of the flange of the brake shoe pusher 9, so that a set gap Δ exists between them, which is adapted to the required brake gap Δ 1, i.e., when the set gap Δ disappears due to the movement of the wheel cylinder piston 6, the brake gap Δ 1 also disappears, and the brake shoe friction plate 10 abuts against the brake drum 1.
Referring to fig. 3, which shows the state when no braking is performed, because no braking is performed, no force is applied to the wheel cylinder piston 6 by the brake fluid in the hydraulic chamber 15 of the wheel cylinder 4, the brake shoe 3 is retracted under the action of the brake shoe return spring 5, the non-support end of the brake shoe 3 forces the brake shoe pusher 9 to move together with the wheel cylinder piston 6 into the wheel cylinder 4 until the flange end face D of the brake shoe pusher 9 abuts against the end face C of the positioning ring 8, because the positioning ring 8 which is interference-fitted in the wheel cylinder 4 cannot be pushed by the force of the brake shoe return spring 5, the brake shoe 3 is no longer retracted, and the required brake gap is maintained between the brake shoe friction plate 10 on the brake shoe 3 and the brake drum 1.
When braking, referring to fig. 2, the brake fluid in the brake wheel cylinder 4 applies force to the wheel cylinder piston 6, so that the wheel cylinder piston 6 extends out of the brake wheel cylinder 4 together with the brake shoe pushing member 9, thereby pushing the brake shoe 3 to open. When the end surface A of the wheel cylinder piston 6 abuts against the end surface B of the positioning ring 8, the brake shoe friction plate 10 abuts against the brake drum 1, and braking is achieved. If the brake clearance is increased due to wear, when the end surface a of the wheel cylinder piston 6 abuts against the end surface of the positioning ring 8, the shoe friction plate 10 is not yet abutted against the brake drum 1, and the positioning ring 8 in interference fit is forced to move under the action of the brake hydraulic pressure until the shoe friction plate 10 abuts against the brake drum 1. If the brake operation is released, under the action of the brake shoe return spring 5, the brake shoe 3 retracts to the end to force the brake shoe pushing member 9 to retract together with the wheel cylinder piston 6 until the end face c of the positioning ring 8 abuts against the flange end face D of the brake shoe pushing member 9, and the inward retraction movement distance is still the set gap Δ, so that the required brake gap between the brake shoe friction plate 10 and the brake drum 1 is still ensured, namely the brake gap is adjusted during the braking process.
Claims (2)
1. An automatic gap regulator for hydraulic brake is composed of wheel cylinder on braking bottom plate, wheel cylinder piston in said wheel cylinder, and the push part of brake shoe for pressing against one end of brake shoe, and features that a locating ring is arranged between the wheel cylinder piston and the push part of brake shoe in said wheel cylinder and is installed in said wheel cylinder in interference fit mode; and a set gap delta is formed between the flange end surface of the brake shoe pushing piece and one end surface of the positioning ring under the braking state, namely under the condition that the brake shoe friction plate is attached to the brake drum, the set gap delta is formed between the end surface of the wheel cylinder piston and the other end surface of the positioning ring under the non-braking state, and the flange end surface of the brake shoe pushing piece is abutted against one end surface of the positioning ring.
2. The apparatus of claim 1, wherein the retaining ring is cup-shaped with a through hole in the center.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95118358 CN1150622A (en) | 1995-11-23 | 1995-11-23 | Automatic gap adjuster for hydraulic brake |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95118358 CN1150622A (en) | 1995-11-23 | 1995-11-23 | Automatic gap adjuster for hydraulic brake |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1150622A true CN1150622A (en) | 1997-05-28 |
Family
ID=5081665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95118358 Pending CN1150622A (en) | 1995-11-23 | 1995-11-23 | Automatic gap adjuster for hydraulic brake |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1150622A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100436857C (en) * | 2003-08-13 | 2008-11-26 | 曙制动器工业株式会社 | Braking device having automatic clearance regulation mechanism with over-regulation protection device |
-
1995
- 1995-11-23 CN CN 95118358 patent/CN1150622A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100436857C (en) * | 2003-08-13 | 2008-11-26 | 曙制动器工业株式会社 | Braking device having automatic clearance regulation mechanism with over-regulation protection device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |