JP2549842Y2 - Disc brake with parking brake mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake with a parking brake mechanism, and more particularly, to a piston, an adjusting bolt screwed with an adjusting nut, and a movable member to which a parking brake operating force is input. A disk brake with a parking brake mechanism that is provided along with a cone clutch formed between one end of an adjustment bolt and a movable member and that automatically adjusts a parking brake operation stroke based on rotation of the adjustment bolt. It is.

[0002]

2. Description of the Related Art A bottomed cylindrical piston that is protrudably fitted into a bottomed cylinder bore that opens in one direction, an adjust nut provided in the piston,
It has a male thread on one end and a first cable on the other end.
And an adjusting bolt inserted into the piston and screwed to the adjusting nut, and an axial movement of the adjusting bolt so as to face the other end of the adjusting bolt in the axial direction. And is provided on the bottom side in the cylinder bore so as to be non-rotatable about the axis and capable of being taperedly fitted to the first tapered surface of the adjusting bolt .
A movable member having two tapered surfaces , an operating force from a parking brake operating member is transmitted to the piston via the movable member, the adjustment bolt, and the adjust nut, and the piston is moved by hydraulic pressure in the cylinder bore. A disc brake with a parking brake mechanism is known which automatically adjusts the operation stroke of the parking brake operation member by rotating the adjustment bolt in one direction with respect to the adjustment nut when the vehicle is protruded.

[0003] For example, this is described in Japanese Patent Publication No. 35857/1988. In this disc brake, a detent pin is press-fitted into a hole formed on a surface of the movable member facing the bottom of the cylinder bore, and a detent pin protruding from the movable member is formed at the bottom of the cylinder bore. By being fitted into the bottom hole, the movable member is prevented from rotating around its axis while allowing the movable member to move in the axial direction. If the rotation of the movable member around the axis is not prevented, the adjusting bolt may be rotated together with the movable member in the direction opposite to the adjustment direction during the parking brake operation, and the parking brake operation stroke may increase. .

[0004]

However, in such a conventional disc brake, since a bottomed hole must be formed in the deep bottom of the cylinder bore, a relatively long drill is required, so that a drilled hole is required. The drill may be broken.

In order to more reliably prevent the rotation of the movable member about the axis, the gap between the detent pin and the bottomed hole in the direction perpendicular to the axis of the detent pin is made as small as possible. If the locking pin is press-fitted into the hole of the movable member in an inclined state, it becomes difficult to insert the locking pin into the bottomed hole at the bottom of the cylinder bore, and the assembling work of the movable member into the cylinder bore In some cases, the properties were impaired or the assembly became impossible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a piston, an adjusting bolt screwed with an adjusting nut, and a movable member to which a parking brake operating force is input. Is provided in the cylinder bore along the axial direction, a cone clutch is formed between one end of the adjustment bolt and the movable member, and the parking brake operation stroke is automatically adjusted based on the rotation of the adjustment bolt. In a disc brake with a brake mechanism, when a recess forming a part of a detent means for preventing rotation of a movable member around an axis is formed by drilling from the opening side to a portion located on the bottom side of a cylinder bore. The movable part which can suppress breakage of the drill in the The invention is to provide the times while the stopper member fitted in said recess and the assembling work when assembling the cylinder bores may be made easily and reliably parking brake mechanism with disc brakes.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a large-diameter cylinder bore portion and a small-diameter cylinder bore portion, which are open on the large-diameter cylinder bore side and have a small-diameter cylinder bore. A bottomed cylinder bore provided with a bottom on the bottom side, a bottomed cylindrical piston protrudably fitted to the large diameter cylinder bore, an adjust nut provided in the piston, and one end the other end side and having a male screw portion
An adjusting bolt having one tapered surface , the external thread portion of which is inserted into the piston and screwed to the adjusting nut, and the axial movement of the adjusting bolt so as to face the other end of the adjusting bolt in the axial direction A second cylinder which is provided in the small-diameter cylinder bore so as to be rotatable around the axis and capable of being taperedly fitted to the first tapered surface of the adjusting bolt .
A movable member having a tapered surface, and an operating force from a parking brake operating member is transmitted to the piston via the movable member, the adjust bolt, and the adjust nut, and the piston is actuated by hydraulic pressure in the cylinder bore. A disc brake with a parking brake mechanism of a type that automatically adjusts the operation stroke of the parking brake operation member by rotating the adjustment bolt in one direction with respect to the adjustment nut when protruding, (a) A groove formed in the inner peripheral surface of the small-diameter cylinder bore portion from the opening side of the cylinder bore and extending in a direction parallel to the axis of the cylinder bore; and (b) forming a C-shape as a whole and toward the outer peripheral side. It has a protruding protrusion, and the outer peripheral surface of the movable member cannot be rotated relative to the axis. A clip for preventing rotation of the movable member around the axis center in a state where the movable member is allowed to move in the axial direction by being fitted into the groove of the small diameter cylinder bore portion while being fitted. And to include.

[0008]

In this way, the groove forming a part of the detent means for preventing the rotation of the movable member around the axis is located on the opening side of the bottom of the cylinder bore. Since the inner peripheral surface of the cylinder bore is formed by drilling from the opening side of the cylinder bore, compared with the conventional case in which a bottomed hole forming a part of the detent means is formed at the bottom of the cylinder bore by drilling from the opening side Since a shorter drill can be used, breakage of the drill during groove processing can be suitably suppressed.

Further, a C-shaped clip is fitted on the outer peripheral surface of the movable member so as to be relatively non-rotatable, and the projection of the clip is fitted into a groove on the inner peripheral surface of the small-diameter cylinder bore portion. When the clip is fitted on the outer peripheral surface of the movable member, the projection of the clip does not tilt around the axis of the movable member, and the projection does not rotate. Since the protrusion does not hinder the fitting of the projection into the groove even when inclined in a direction substantially parallel to the center, the locking pin fitted into the bottomed hole in the bottom of the cylinder bore is inclined to the hole of the movable member. Compared to the conventional case that may be press-fitted,
The work of assembling the movable member to the cylinder bore can be more easily and reliably performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a main part of a disk brake with a parking brake mechanism to which the present invention is applied, and a disk rotor 1 rotatably provided with wheels.
A caliper 12 is provided on the outer periphery of the disk rotor 10 via a pair of slide pins (not shown) on a support member 14 fixed to a non-rotating member (not shown). It is supported movably in a direction parallel to the heart. The caliper 12 has a first cylinder bore 16 in which a piston 18 having a cylindrical shape with a bottom as a whole is fitted in the first cylinder bore 16 so as to protrude in one direction in a state in which the piston 18 cannot rotate around an axis. Part 20, a protruding part 22 provided integrally with the cylinder part 20 at an end of the cylinder part 20 opposite to the direction in which the piston 18 protrudes, and integrally extending from the end of the cylinder part 20 in the direction in which the piston 18 protrudes. A bifurcated claw portion 24 is provided to face the cylinder portion 20 with the disk rotor 10 protruding therebetween. A pair of pads 26 and 28 are disposed inside the caliper 12, that is, between the piston 18 and the claw portion 24, with the disk rotor 10 being sandwiched between the pads 26 and 28. The disk rotor 10 is supported so as to be movable in a direction parallel to the axis of the disk rotor 10.

An adjust nut 32 having a cylindrical shape as a whole and having an outward flange 30 on one end side outer peripheral surface is provided inside the piston 18.
Is located on the bottom side of the piston 18, the piston 1
8 is provided so as to be movable relative to the shaft 8 in the axial direction and not to rotate relative to the axis. A spring 38 is provided between the outward flange 30 of the adjust nut 32 and the inner peripheral surface of the piston 18 through a retaining ring 34 and a washer 36 fitted on the inner peripheral surface of the piston 18 in a pre-pressed state. The adjusting nut 32 is connected to the spring 3
8 is pressed against the bottom of the piston 18 according to the urging force of the piston 8.

Inside the cylinder portion 20, a second cylinder bore 40 and a third cylinder bore 42 are sequentially formed concentrically with the first cylinder bore 16, and the first cylinder bore 16, the second cylinder bore 40, and the third cylinder bore 40 are formed. The diameter is reduced in the order of 42 and a bottom 43 is provided on the third cylinder bore 16 side. In this embodiment, the first cylinder bore 16, the second cylinder bore 40, and the third cylinder bore 42 constitute a cylinder bore, the first cylinder bore 16 constitutes a large-diameter cylinder bore, and the third cylinder bore 42 constitutes a small-diameter cylinder bore. Each is composed. An adjust bolt 44 is provided in each of the three cylinder bores 16, 40, 42. The adjusting bolt 44 is connected to the male screw 4
6, a fitting portion 48 having a diameter larger than that of the male screw portion 46, and a head having a tapered outer peripheral surface 50 having a diameter larger than that of the fitting portion 48 and having a diameter decreasing as the distance from the male screw portion 46 increases. 52, and the male screw portion 46 is screwed to the adjust nut 32 in a state having a predetermined gap in the axial direction.

A movable member 58 having a tapered inner peripheral surface 54 at one end in the axial direction and an engaging recess 56 at the other end is provided in the third cylinder bore 42 in the axial direction. It is movably fitted. As shown in FIGS. 1 to 3, an annular groove 60 having a width slightly larger than the thickness of a clip 64 described later is formed on the outer peripheral surface of the movable member 58, and the bottom of the annular groove 60. As shown in FIG. 2, a part of the bottom of the annular groove 60 is cut away from a direction perpendicular to the axis of the movable member 58 so as to be substantially opposite to each other. A pair of notches 62, 62 extending in parallel are formed.

A clip 64 having a C shape as a whole is fitted into the annular groove 60 of the movable member 58 such that the clip 64 cannot rotate around the axis with respect to the movable member 58 and cannot move in a direction parallel to the axis. . The clip 64 is formed, for example, by stamping a metal plate-shaped material by pressing, and is a substantially semicircle protruding in the opposite direction from the outer peripheral surface located near both ends of the C-shape to the outer peripheral side. A pair of projections 66, 66 having a shape are provided.
6 are fitted in the annular groove 60 so as to protrude from the outer peripheral surface of the movable member 58, and are formed at the inner peripheral edges near both ends of the C-shape, and are parallel portions 67, 67 which are substantially parallel to each other. The rotation about the axis with respect to the movable member 58 is prevented based on the engagement of the notches 62 with the bottoms of the notches 62.

Drilling is performed on the inner peripheral surface of the third cylinder bore 42 and at a position radially opposite to each other from the opening on the side of the first cylinder bore 16 so as to be parallel to the cylinder bore axis. And a pair of grooves 68, 68 having a semicircular cross section perpendicular to the cylinder bore axis and slightly larger than the protrusions 66, 66 are formed. The projections 66, 66 of the clip 64 fitted in the annular groove 60 of the movable member 58 are respectively fitted in these grooves 68, 68, so that the clip 64 with respect to the inner peripheral surface of the third cylinder bore 42. Rotation around the axis is prevented. Thus, clip 6
4 rotates about the axis with respect to the movable member 58.
4 and the notches 62, 62 of the movable member 58.
The rotation of the clip 64 about the axis with respect to the inner peripheral surface of the third cylinder bore 42 is prevented by the engagement with the bottom of the third cylinder bore 42 and the projections 66, 66 of the clip 64 and the third cylinder bore 4
2 is prevented based on the engagement of the inner peripheral surface with the grooves 68, 68, so that the movable member 58 is allowed to move in the axial direction with respect to the inner peripheral surface of the third cylinder bore 42 of the movable member 58. Rotation around the axis is prevented. 2 and 3, for convenience, the third cylinder bore 4
The gap between the inner peripheral surface of the movable member 58 and the outer peripheral surface of the movable member 58 and the gap between the protrusions 66, 66 and the grooves 68, 68 are drawn larger than actual.

A washer 72 and an adjustment bolt 4 are fixed to the inner peripheral surface between the first cylinder bore 16 and the second cylinder bore 40 by a retaining ring 70 so as to be immovable in one direction.
4 and a spring 80 via a thrust bearing 78 sandwiched between a pair of washers 74 and 76.
Is provided in a pre-pressurized state, whereby the adjustment bolt 44 is urged toward the side opposite to the bottom of the piston 18 in accordance with the urging force of the spring 80, and the adjustment bolt 4
The fourth tapered outer peripheral surface 50 is pressed against the tapered inner peripheral surface 54 of the movable member 58. Adjust
The tapered outer peripheral surface 50 of the bolt 44 corresponds to the first tapered surface
The inner peripheral surface 54 of the movable member 58 has a second tapered surface.
Is equivalent to The spring constant of the spring 80 is smaller than the spring constant of the spring 38.

A mounting hole 82 extending in a direction perpendicular to the axis of the third cylinder bore 42 or the like is provided inside the protruding portion 22 so as to communicate with the bottom of the third cylinder bore 42. Inside, a cam shaft 84 is provided via a needle bearing 86 so as to be rotatable around the axis. A lever member 90 to which a parking brake operation force is transmitted from a parking brake operation member (not shown) via a parking cable 88 to a portion located at one end portion of the cam shaft 84 and outside the protrusion 22 so as to be relatively unable to rotate. Installed. An engaging notch 92 having an eccentric position as a bottom is formed at an intermediate portion of the outer peripheral surface of the cam shaft 84 in the longitudinal direction, and the bottom of the engaging notch 92 and the movable member 58 are formed.
A toggle 94 is provided between the engaging recess 56 and the bottom of the engaging recess 56. Reference numeral 96 denotes a piston seal that seals a gap between the outer peripheral surface of the piston 18 and the inner peripheral surface of the first cylinder bore 16 in a liquid-tight manner and performs a return operation of the piston 18, and 98 denotes a dust boot.

Between the inner peripheral surface of the second cylinder bore 40 and the outer peripheral surface of the fitting portion 48 of the adjusting bolt 44, an annular partition member 100 is provided with a retaining ring 70 and a washer 72, the second cylinder bore 40 and the second cylinder bore 40. In a state where the relative movement in the axial direction with respect to the second cylinder bore 40 is restricted by the stepped surface between the three cylinder bores 42, the adjustment bolt 44 is axially relatively movable and is fitted in a liquid-tight manner. Thus, the hydraulic chamber 102 is formed in the first cylinder bore 16 provided with the male thread portion 46 of the adjusting bolt 44, the piston 18 and the like with the partition member 100 interposed therebetween, and the head 52 of the adjusting bolt 44 is formed. An atmospheric pressure chamber 104 is formed in the third cylinder bore 42 in which the movable member 58 and the like are provided, and when the brake fluid pressure is supplied into the fluid pressure chamber 102, the movable member 5 corresponding to the fluid pressure is provided.
The thrust to the 8 side is made to act on the adjustment bolt 44.

Next, the operation of the disc brake with a parking brake mechanism will be described. First, when the parking brake is operated, when the camshaft 84 is rotated clockwise in FIG. 1 by the lever member 90, the toggle 94 is pushed to the left in FIG.
The thrust generated at the toggle 94 is transmitted to the piston 18 via the movable member 58, the adjustment bolt 44, and the adjustment nut 32, and the piston 18 is protruded.
As a result, one of the pads 28 is pressed against the disk rotor 10, and the reaction force causes the caliper 12 to move in the direction opposite to the direction in which the piston 18 protrudes. The brake is actuated.

During the service brake operation of the disc brake, the piston 18 is protruded by the brake fluid pressure supplied into the fluid pressure chamber 102, and braking is performed in the same manner as described above. At this time, when the piston 18 protrudes within a predetermined movement range where relative slip does not occur between the outer peripheral surface of the piston 18 and the piston seal 96, the adjusting nut 32 is
8, the piston is operated integrally with the piston 18 while being pressed against the bottom of the piston 18, and the gap between the adjustment nut 32 and the adjustment bolt 44 in the axial direction (play) causes the adjustment nut 32 to No axial force acts between the bolt 44. On the other hand, when the brake fluid pressure is lower than a predetermined constant pressure, and the brake fluid pressure and the biasing force of the spring 80 toward the bottom side of the piston 18 with respect to the adjustment bolt 44 are smaller than the biasing force of the spring 38, If the pistons 18 protrude beyond the predetermined range of movement due to wear of the pads 26 and 28, causing relative slip between the outer peripheral surface of the piston 18 and the piston seal 96, the adjusting nut 46 An axial force is generated between the adjusting bolt 36 and the adjusting bolt 4.
4 is moved toward the bottom of the piston 18 against the urging force of the spring 80, whereby the adjusting bolt 44 is moved.
Until the tapered outer peripheral surface 50 separates from the tapered inner peripheral surface 54 of the movable member 58 and the adjuster bolt 44 is pressed by the spring 80 until the tapered outer peripheral surface 50 is taperedly engaged with the tapered inner peripheral surface 54. By rotating the lever in the direction, the amount of rotation of the lever member 90 and thus the operation stroke of the parking brake operation member are automatically adjusted.

If the brake fluid pressure becomes excessive, the piston 18 may protrude beyond the predetermined moving range due to deformation of the caliper 12 irrespective of the wear of the pads 26 and 28. However, when the brake fluid pressure increases and exceeds the predetermined fixed pressure, the bias fluid and the urging force of the spring 80 toward the adjustment bolt 44 toward the side opposite to the bottom of the piston 18 become smaller than the urging force of the spring 38. Become big, piston 1
The adjusting nut 32 separates from the bottom of the piston 18 while the spring 38 is compressed with the protrusion of the movable member 8, and the tapered outer peripheral surface 50 of the adjusting bolt 44 moves the movable member 5.
8, the adjusting bolt 44 is prevented from rotating based on the frictional force between the tapered outer peripheral surface 50 and the tapered inner peripheral surface 54, and the parking brake operating member Over-adjustment of the operation stroke is prevented.

As described above, according to the present embodiment, the grooves 68, 68 constituting a part of the rotation stopping means for preventing the rotation of the movable member 58 around the axis are located closer to the opening than the bottom of the cylinder bore. Since the inner peripheral surface of the third cylinder bore 42 is formed by drilling from the opening side of the cylinder bore, a bottomed hole forming a part of the detent means is drilled at the bottom of the cylinder bore from the opening side. Since a shorter drill can be used as compared with the conventional case in which the grooves are formed, breakage of the drill during processing of the grooves 68, 68 can be suitably suppressed.

When the movable member is assembled on the bottom side of the cylinder bore, a locking pin protruding from the movable member by press-fitting is fitted into a bottomed hole formed in the bottom of the cylinder bore, so that the inside of the cylinder bore of the movable member is reduced. In a conventional disc brake with a parking brake mechanism that prevents rotation about the axis with respect to the peripheral surface, it is difficult to insert the detent pin into the bottomed hole by pressing the detent pin into the movable member in an inclined state. As a result, the workability of assembling the movable member to the cylinder bore may be impaired or may not be possible. On the other hand, according to the present embodiment, when the clip 64 is fitted on the outer peripheral surface of the movable member 58, the projections 66, 66 of the clip 64 never tilt in the direction around the axis of the movable member 58, and Even if the projections 66, 66 are slightly inclined in a direction substantially parallel to the axis of the movable member 58, there is no problem at all in fitting the projections 66, 66 into the grooves 68, 68 of the third cylinder bore 42. In addition, the work of assembling the movable member 58 to the third cylinder bore portion 42 can be performed more easily and more reliably than in the above-described conventional case.

According to this embodiment, the clip 64 can be easily attached to the movable member 58 simply by fitting the clip 64 into the annular groove 60 of the movable member 58 from a direction perpendicular to the axis of the movable member 58. Therefore, there is an advantage that a relatively troublesome press-fitting operation of press-fitting the locking pin into the hole of the movable member as in the related art is unnecessary.

While the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the above embodiment, a pair of grooves 6
8, 68 and a pair of protrusions 66, 66 are provided, but one or three or more grooves and protrusions may be provided.

In the above-described embodiment, the detent means between the movable member 58 and the clip 64 is provided at the notch 62, 62 provided at the bottom of the annular groove 60 of the movable member 58 and at the inner peripheral edge of the clip 64. The movable member 58 is formed of a hole formed in the bottom of the annular groove 60 and a projection formed on the inner peripheral surface of the clip 64. You can also.

In the above embodiment, the annular groove 60 is formed on the outer peripheral surface of the movable member 58, and the portion of the clip 64 except for the projections 66, 66 is located in the annular groove 60. In the case where the movable member 58 is accommodated in the third cylinder bore 42 with a relatively large gap between the movable member 58 and the inner peripheral surface thereof, the outer peripheral surface of the movable member can be provided without providing such an annular groove 60. The clip may be configured to be attached so that it cannot rotate relative to the axis.

In the above embodiment, a tapered fitting portion (cone clutch) between the tapered outer peripheral surface 50 of the adjusting bolt 44 and the tapered inner peripheral surface 54 of the movable member 58 is provided in the atmospheric pressure chamber 102. Also, the case where the present invention is applied to a disc brake with a parking brake mechanism having a function of preventing over-adjustment of the parking brake operation stroke has been described. However, in the present invention, the cone clutch between the adjustment bolt and the movable member is hydraulically operated. Of course, the present invention can also be applied to a disc brake with a parking brake mechanism provided in a room or a disc brake with a parking brake mechanism that does not have a function of preventing an overadjustment of a parking brake operation stroke.

In addition, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a disk brake with a parking brake mechanism to which the present invention is applied, showing a main part thereof.

FIG. 2 is an enlarged view showing a main part of a cross section taken along line II-II of FIG.

FIG. 3 is an enlarged view showing a main part of a section taken along line III-III in FIG. 2;

[Explanation of symbols]

# 16 1st cylinder bore (large-diameter cylinder bore), 4
0 Second cylinder bore, 42 Third cylinder bore (small diameter cylinder bore)｝ Cylinder bore 18 Piston 32 Adjust nut 43 Bottom 44 Adjust bolt 46 Male thread 50 Tapered outer peripheral surface (first tapered surface) 54 Tapered inner peripheral surface (second tapered surface) Surface) 58 movable member 64 clip 66 protrusion 68 groove

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-192136 (JP, A) JP-A-63-246523 (JP, A) JP-A-1-164825 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] A bottomed cylinder bore having a large-diameter cylinder bore portion and a small-diameter cylinder bore portion, opening on the large-diameter cylinder bore portion side and having a bottom provided on the small-diameter cylinder bore portion side; A cylindrical piston with a bottom fitted protrudably, an adjust nut provided in the piston, a male thread portion on one end side, and a first tapered surface on the other end side; An adjust bolt inserted into the piston and screwed to the adjust nut; and an axially movable and non-rotatable axial center opposed to the other end of the adjust bolt in the axial direction. A movable member provided in the small-diameter cylinder bore portion and having a second tapered surface capable of being taperedly fitted to the first tapered surface of the adjusting bolt; The operating force from the working member is transmitted to the piston through the movable member, the adjustment bolt, and the adjustment nut, and when the piston is protruded by the hydraulic pressure in the cylinder bore, the adjustment bolt is moved to the adjustment nut. A disk brake with a parking brake mechanism of a type in which the operation stroke of the parking brake operation member is automatically adjusted by being rotated in one direction with respect to an inner peripheral surface of the small-diameter cylinder bore portion from an opening side of the cylinder bore. A groove formed by drilling and extending in a direction parallel to the axis of the cylinder bore; and a projection having a C-shape as a whole and protruding to the outer peripheral side. The protrusion is fitted into the groove of the small-diameter cylinder bore portion so that it cannot be rotated. By being is, the parking brake mechanism with disc brakes, characterized in that it comprises a clip for preventing rotation of said axis around the movable member in a state that allows movement of said axial movable member.