JP3844312B2 - Manual adjustment mechanism for parking brake type parking brake - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a manual adjustment mechanism of a disc brake type parking brake dedicated to parking, and can simplify the manual adjustment mechanism of the parking brake and improve the workability of the adjustment work.
[0002]
[Prior art]
Disc brake type parking brake devices dedicated to parking are roughly divided into British Lucas type, that is, ball cam type mechanical disc brakes, and German Perot type, that is, eccentric cam type mechanical disc brakes.
The British Lucas type has the structure shown in FIG. 5, and includes a ball cam follower 2 that is rotated by the lever 1, an adjustment nut member 3 fitted to the ball cam follower 2, and the adjustment nut member 3. It has a piston composed of a threaded rod member 4 that is screwed, and presses a brake pad by the threaded rod member 4. An adjustment pinion 5 disposed radially outward of the ball cam follower 2 is adjusted with an adjustment nut. After engaging the gear 6 of the member 3 and removing the cap 7, the adjustment shaft 8 is rotated to rotate the adjustment pinion 5, thereby rotating the adjustment nut member 3 and pushing out the screw rod 4. The clearance between the brake pad and the brake disc is adjusted. Since the adjustment pinion 5 and the adjustment shaft 8 are arranged radially outward of the ball cam follower 2, the cylinder 9 is enlarged, and a sealing seal for sealing the accommodation portion of the adjustment pinion 5 is provided. The manufacturing cost increases because it is large and deformed.
Further, the German Perot type has the structure shown in FIGS. 6 and 7, and an eccentric cam 11 that is rotated by a lever 10, a piston 13 that is pushed out by a bearing plate 12 by the eccentric cam 11, and the piston 13, and a brake pad is pressed by the screw rod 14 through a pressure plate 15.
A hexagon wrench is inserted through the hole 17 of the support member 16 to rotate the screw rod 14 forward, thereby adjusting the gap between the brake pad and the brake disc. In this case, since the area of the pressure surface of the screw rod 14 is small, the pressure plate 15 is indispensable for improving the surface pressure distribution of the pressure surface, and the adjustment mechanism is complicated accordingly, and the hole 17 of the support member 16 is also made. Since the hexagonal wrench is inserted and the screw rod is directly rotated by this, the rotation resistance is large and the work space for rotating the screw rod is narrow, so this adjustment operation is not easy.
[0003]
[Problems to be solved by the invention]
It is an object of the present invention to solve the above-mentioned problems in the German Perot type, to eliminate the pressure plate, and to devise an adjustment mechanism so that the adjustment work can be performed lightly and easily. To do.
[0004]
[Means for Solving the Problems]
The means taken for solving the above problems is constituted by the following elements (a) to (d) on the premise of a disc brake type parking brake in which a piston is pushed out by an eccentric cam and a brake pad is pressurized by the piston. It is.
(A) A cylindrical portion is provided at the center of the piston, a piston rod is screwed into the cylindrical portion, a gear is provided on the inner peripheral surface of the piston, and an adjustment pinion is engaged with the gear.
(B) A link is interposed between the piston rod and the eccentric cam, and the piston is pushed out against the return spring by the eccentric cam via the link. (C) The adjustment pinion is moved to the adjustment shaft. The adjustment shaft is supported rotatably in the through hole of the support member provided at the tip, with the eccentric cam sandwiched on the opposite side of the operation lever, and the rear end of the adjustment shaft protrudes outside the support member. ,
(D) The lock nut is screwed into the protruding portion at the rear end of the adjustment shaft, and the lock nut is tightened to fix the adjustment shaft to the cylinder block in the axial direction and the rotation direction.
[0005]
[Operation]
When the adjustment shaft is rotated after the lock nut of the adjustment shaft is loosened, the piston is rotated by the adjustment pinion provided at the tip. Since the rotation of the piston rod screwed into the cylindrical portion provided at the center of the piston is regulated by the eccentric cam via the link, the piston rotates relative to the piston rod by the above rotation. When the piston rotates relative to the piston rod, the piston moves forward by the screw between them, and the brake clearance is adjusted. When the adjustment shaft is locked again by tightening the lock nut after adjusting the gap, the rotation of the piston is blocked by the adjustment pinion, so that the rotation of the piston is blocked and the adjusted state is maintained.
Since the adjustment shaft is supported by the through-hole of the support member provided on the opposite side of the operation lever with the eccentric cam interposed therebetween, the adjustment shaft is rotatably supported. It is sufficiently possible to rotate the protruding end of the adjustment shaft. Also, instead of directly rotating the piston rod with a tool, the pinion at the tip of the adjustment shaft is rotated, and the large-diameter piston is rotated with this pinion (deceleration by the pinion and the gear on the piston inner surface). Since the piston is rotated through the mechanism), the adjustment shaft can be rotated lightly. Therefore, this adjustment operation is performed easily and lightly.
The piston rod is pushed out through the link by the eccentric cam, the piston is pushed out through the screwed portion of the piston rod with the piston, and the brake pad is pressurized by this piston. Is sufficiently secured. Therefore, since it is not necessary to improve the surface pressure distribution of the pressure applied by the piston, it is not necessary to interpose a pressure plate between the piston and the brake pad.
[0006]
【Example】
Next, an embodiment will be described with reference to FIGS.
The brake lever (control lever) 20 is pushed forward (leftward in FIG. 1) by the air actuator A to rotate the eccentric cam 21 counterclockwise, and the piston 22 is pushed out via the link 25 and held by the caliper. The brake pads 23 and 23 are pressurized to squeeze the brake disc (rotor) 24 and brake it. This basic mechanism and operation is not different from the above-mentioned Perot type parking disc brake type parking brake.
The piston 22 has a cylindrical portion 22a at the center. The cylindrical portion 22a is provided integrally with the piston 22 by fitting the protruding portion at the tip of the cylindrical portion 22a into a hole provided in the center of the bottom of the piston 22 and caulking the protruding portion. An internal thread 22b is provided on the inner surface of the cylindrical portion 22a, and an internal gear 22c is provided on the inner surface of the piston 22.
The piston rod 30 is a male screw member, and is screwed into the female screw 22 b of the cylindrical portion 22 a at the center of the piston 22.
A hollow cylindrical body (cylinder) 31 is fixed to the support member S with bolts, and a piston 22 is slidably fitted to the hollow cylindrical body 31. Between the hollow cylindrical body 31 and the support member S, a flange 32a at the open end of the cup-shaped spring retainer 32 is sandwiched and fixed. On the other hand, a flange 22d is provided on the outer periphery of the end of the cylindrical portion 22a of the piston, and a return spring 34 is interposed between the spring retainer 32 and the flange 22d, thereby urging the piston 22 in the return direction. .
An adjustment pinion 36 is provided at the tip of the adjustment shaft 35, and the adjustment shaft 35 is rotatably supported in a through hole 37 of the support member S provided on the opposite side of the operation lever 20 with the eccentric cam 21 therebetween. The rear end protrudes outward from the support member S. The adjustment pinion 36 meshes with the internal gear 22 c of the piston 22. The adjustment shaft 35 has a flange 35a. The lock nut 35b screwed to the rear end of the adjustment shaft 35 is tightened, and the support member S is clamped by the lock nut 35b and the flange 35a. It is fixed in the direction and direction of rotation. A hexagonal portion or a hexagonal hole is provided at the rear end of the adjusting shaft 35, and a tool such as a hexagonal box or a hexagonal wrench is attached to the hexagonal portion or hexagonal hole so that the adjustment shaft 35 can be rotated.
When the lock nut 35b is loosened and a tool such as a hexagon box or a hexagon wrench is attached to the rear end of the adjustment shaft 35 and rotated, the adjustment pinion 36 rotates, thereby rotating the piston 22. . At this time, since the rotation of the piston rod 30 is regulated by the eccentric cam 21 via the link 25, the piston 22 moves forward by screwing between the piston rod 30 and the cylindrical portion 22a, and the gap is adjusted. After the adjustment is completed, the lock nut 35b is tightened again to fix the adjustment shaft 35. As a result, the piston 22 is prevented from rotating by the adjustment pinion 36, and the adjustment pinion 36 and the internal gear 22c of the piston 22 are axial ( Since they can slide in the front-rear direction), this prevents the piston from moving forward and backward, and the piston 22 can only move forward and backward.
It is also possible to form an external gear on the outer peripheral surface of the piston 22 and engage the adjustment pinion 36 with the external gear. In this case, a pocket for accommodating the adjustment pinion 36 is provided as a hollow cylindrical body 31. In addition, the position of the adjusting shaft is far away from the eccentric cam 21. Therefore, the embodiment shown in the drawing is superior in view of a request to make the entire mechanism as compact as possible and a request to simplify the shape and structure of the hollow cylindrical body 31 as much as possible.
The piston rod 30 is a cylindrical hollow member, and a female screw is formed on the inner surface thereof. The cylindrical portion 22a at the center of the piston 22 is formed as a solid shaft, and a male screw is formed thereon. A cylindrical hollow member is formed on the male screw. It is also possible to adopt a mode in which the internal thread of the piston rod is screwed. In this case, the flange 22d cannot be provided on the cylindrical portion 22a, and therefore it is difficult to provide the flange on the piston. Therefore, in this sense, the illustrated embodiment is superior.
[0007]
[Effect]
The invention that solves the above-mentioned problems of the present invention is not publicly known. Therefore, by solving the above problems, the shape of the sealing seal of the cylinder etc. is simplified and the brake device is made compact compared to the above-mentioned conventional technology, that is, the disc brake type parking brake dedicated to British Lucas type and Parkin. The reduction in size and weight is an effect unique to the present invention. In addition, the pressure area on the tip of the piston can be increased compared to the disc brake type parking brake dedicated to Perkin, which is a German Perot type. The mechanism can be simplified.
The brake device of the present invention has the same basic structure as the German Perot type. However, since the piston is rotated via the adjustment pinion by the adjustment shaft, this has a deceleration action (or a boosting action). Therefore, adjustment work can be performed lightly. Further, since the adjustment shaft can be fixed by a simple mechanism using a lock nut, and the rotation of the piston is thereby prevented, fluctuation after adjustment can be reliably prevented by a simple mechanism. These are great advantages of the present invention.
A service brake device that also serves as a parking brake is known as a mechanically similar device to the brake device of the present invention. For example, what is described in Japanese Utility Model Laid-Open No. 3-73734 microfilm is an example. In this system, a piston driven by hydraulic pressure is pushed out by an eccentric cam rotated by an operation lever through a link and an adjustment screw rod. The gap adjustment mechanism of this type is an automatic adjustment mechanism with a complicated mechanism, and it is impossible to employ a manual adjustment mechanism because the piston is hydraulically driven. This is similar to the present invention at first glance, but is different from the present invention in that it is different from the present invention and does not include any of the above solutions (A) to (D). This is completely different from the present invention.
In addition, a cup-type spring retainer can be easily and easily assembled in the cylinder by adopting a mechanism in which a portion (cylinder) to which the piston is fitted and supported is used as a hollow cylindrical body and fixed to a support member with a bolt. it can.
[Brief description of the drawings]
FIG. 1 is a sectional view of an embodiment of the present invention.
FIG. 2 is a front view of FIG. 1;
3 is a cross-sectional view taken along the line XX in FIG.
FIG. 4 is an enlarged view of a main part of FIG. 1;
FIG. 5 is a cross-sectional view of a conventional example of the British Lucas type.
FIG. 6 is a cross-sectional view of a conventional example of a German Perot type.
7 is an exploded perspective view of the main part of FIG. 6. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Lever 2 ... Ball cam follower 3 ... Adjustment nut member 4 ... Screw rod member 5 ... Adjustment pinion 6 ... Gear 7 ... Cap 8 ... Adjustment shaft 9 ... Cylinder 10 ... Lever 11 ... Eccentric cam 12 ... Bearing plate 13 ... Piston 14 ... Screw rod 15 ... Pressure plate 16 ... Support member 17 ... Hole 20 ...・ Brake lever (operating lever)
21 ... eccentric cam 22 ... piston 22a ... cylindrical part 22b ... female screw 22c ... internal gear 22d ... flange 23 ... brake pad 24 ... brake disc 25 ... Link 30 ... Piston rod 31 ... Hollow cylinder (cylinder)
32 ... Cup type spring retainer 32a ... Flange 34 ... Return spring 35 ... Adjustment shaft 35a ... Flange 35b ... Lock nut 36 ... Adjustment pinion 37 ... Through hole A ..Air actuators s support members

Claims (2)

In a disc brake type parking brake that pushes the piston with an eccentric cam and pressurizes the brake pad with this piston,
A cylindrical part is provided at the center of the piston, a piston rod is screwed into this cylindrical part, a gear is provided on the inner peripheral surface of the piston, and an adjustment pinion is meshed with this gear.
A link is interposed between the piston rod and the eccentric cam, and the piston is pushed out against the return spring by the eccentric cam via the link.
The adjustment pinion is provided at the tip of the adjustment shaft, and the adjustment shaft is rotatably supported in the through hole of the support member provided on the opposite side of the operation lever with the eccentric cam interposed therebetween, and the rear end of the adjustment shaft is supported by the support member. Project outside the
A parking brake manual adjustment mechanism for exclusive use of parking, in which a lock nut is screwed into a protruding portion at the rear end of the adjustment shaft, and the lock nut is tightened to fix the adjustment shaft to the cylinder block in the axial direction and the rotation direction. The manual adjustment mechanism of a disc brake type parking brake for parking according to claim 1, wherein a portion (cylinder) to which the piston is fitted and supported is a cylindrical member and is fixed to the supporting member by a bolt.

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