JPH0356663Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a disc brake with a parking brake function.

Prior Art A cylindrical piston with a bottom fitted into a cylinder portion of a caliper is pushed out via an adjustment nut screwed onto an adjustment bolt that is reciprocated in the axial direction in connection with the operation of a parking brake operating member. A disc brake is known which has a parking brake function in which the adjustment nut is allowed to rotate in only one direction due to the frictional resistance between the adjustment nut and a clutch spring wound around its outer circumferential surface. Although a torsion coil spring is normally used as the clutch spring, it is conceivable to use a plate spring bent into a substantially annular shape. In this case, one end of the leaf spring protrudes a predetermined distance toward the outer circumference, and the one end is formed on the inner circumferential surface of the piston or on the inner circumferential surface of an annular member provided integrally with the inner circumferential surface. By fitting the leaf spring into an engagement groove extending in a direction parallel to the axis of the piston, relative rotation of the leaf spring with respect to the piston is prevented, and the leaf spring allows rotation of the adjustment nut in only the one direction. The Rukoto.

Problems to be solved by the invention However, the width dimension of the above-mentioned engagement groove is usually
In order to reliably prevent relative rotation of the leaf spring with respect to the piston, the dimensions are relatively small, slightly larger than the thickness of the leaf spring, so if such an engagement groove is formed by post-processing, it is difficult to process it properly. There is a problem that it is difficult to obtain sex.

Means for Solving the Problems The present invention was made against the background of the above circumstances, and its purpose is to provide a technique for improving the workability of the engagement groove. be. In order to achieve this object, the present invention provides a disc brake with a parking brake function of the type described above, which includes an annular member integrally provided on the inner circumferential surface of the piston or the inner circumferential surface of the piston. An engagement groove extending in a direction parallel to the axis of the piston is provided on the inner circumferential surface of the clutch spring, and the clutch spring is formed of a plate spring bent into a substantially annular shape, and one end of the plate spring is provided with an engaging groove extending in a direction parallel to the axis of the piston. a protrusion that protrudes toward the outer circumference; and a protrusion that extends a predetermined distance from the tip of the protrusion in a direction intersecting the protrusion direction of the protrusion, and that is non-rotatable relative to the engagement groove and about the axis of the piston, and that is parallel to the axis. It is characterized in that it is integrally provided with an engaging portion that can be engaged so as to be relatively movable in the direction.

Operation and Effect of the Invention According to this structure, a protrusion protruding toward the outer circumference is provided at one end of the leaf spring, and the protrusion extends a predetermined distance from the tip of the protrusion in a direction intersecting the protruding direction of the protrusion. An engaging part is provided,
Since this engaging part is engaged with the engaging groove piston so that it cannot rotate relative to the piston and can move relatively in a direction parallel to the axis, the width dimension of the engaging groove is equal to the extension of the engaging part. The size is slightly larger than the size. As a result, the width of the engagement groove can be made sufficiently larger than the thickness of the leaf spring, so that when the engagement groove is formed by post-processing, the workability can be improved.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

FIG. 2 is a diagram showing the main parts of a disc brake with a parking brake function to which the present invention is applied, in which a caliper 12 is installed straddling the outer periphery of a disc rotor 10 that is rotatably provided with the wheels. The caliper 12 is supported movably in a direction parallel to the axis of the disk rotor 10 by a support member 14 fixed to a non-rotating member (not shown) via a slide pin (not shown) or the like. The caliper 12 has a first cylinder bore 16, into which a piston 18 having an overall cylindrical shape with a bottom is fitted so as to be able to protrude in one direction without being able to rotate relative to the axis. Cylinder part 20 and piston 1 of the cylinder part 20
A protruding part 22 is integrally provided on the cylinder part 20 at an end opposite to the protruding direction of the piston 18, and a protruding part 22 integrally extends from the end of the cylinder part 20 in the protruding direction of the piston 18, with the disc rotor 10 in between. It has a bifurcated claw part 24 facing the part 20. A pair of pads 2 are located inside the caliper 12, that is, between the piston 18 and the claw portion 24.
6 and 28 are disposed with the disc rotor 10 sandwiched therebetween, and these pads 26 and 28 are supported by the support member 14 so as to be movable in a direction parallel to the axis of the disc rotor 10.

A second cylinder bore 30 is formed inside the protruding member 22 adjacent to and approximately concentrically with the first cylinder bore 16, and the second cylinder bore 30 has a male threaded portion 32 and a head having a larger diameter. An adjusting bolt 36 having a diameter of 34 is fitted in the head 34 so as to be relatively movable in the axial direction, with the male threaded portion 32 of the adjusting bolt 36 positioned within the piston 18 . The adjusting bolt 36 has its head 34
and a washer 38 that is integrally provided on the inner peripheral surface of the first cylinder bore 16.
It is always urged in a direction away from the piston 18, and an adjustment nut 42 is screwed into the male threaded portion 32. A flange portion 44 protruding toward the outer circumferential direction is provided at the end of the adjusting nut 42 located on the tip side of the male thread portion 32. The adjusting nut 42 is formed on the outer circumferential surface of the flange portion 44, and has a tapered surface on which the piston 18 is tapered. The inner wall and the piston 18 are brought into contact with each other in the direction of protrusion.

As shown in FIGS. 1 and 2, on the outer circumferential surface of the adjuster nut 42 and located closer to the head 34 than the flange portion 44, a plate spring 46 curved into a substantially annular shape is provided at a predetermined position. It is fitted with a tightening force. On the other hand, as shown in FIGS. 1 and 2, the inner circumferential surface of the piston 18 at a position corresponding to the leaf spring 46 has an outer circumferential shape that is opposed to the flange portion 44 in the axial direction. An oval-shaped annular member 48 is integrally fixed by caulking. An engagement groove 50 extending in a direction parallel to the axis is formed in the inner peripheral surface of the annular member 48, and the plate spring 4 is formed in this engagement groove 50.
One end portion of 6 is engaged so as to be non-rotatable relative to the shaft center and movable relative to the shaft center in a direction parallel to the shaft center.
This allows the adjusting nut 42 to rotate in one direction, that is, in the direction away from the head 34 of the adjusting bolt 36, but prevents it from rotating in the opposite direction. The fitting direction of the leaf spring 46, the predetermined tightening force, etc. are thus determined in advance. The flange portion 44
A thrust bearing 52 is inserted between the annular member 48 and the outer peripheral surface of the flange portion 44 so that there is play at a predetermined interval when the outer circumferential surface of the flange portion 44 is in contact with the inner wall of the piston 18 in the direction in which the piston 18 protrudes. ing. Note that 53 is a piston seal that liquid-tightly seals between the piston 18 and the first cylinder bore 16 and also serves to return the piston 18.

As shown in FIG. 2, inside the protrusion 22, there is further a through hole 54 that penetrates in a direction perpendicular to the axis of the second cylinder bore 30 on the side opposite to the first cylinder bore 16 side of the second cylinder bore 30. A rotary shaft 56 is provided in communication with the second cylinder bore 30, and a rotating shaft 56 is disposed within the through hole 54 of the bearing 5.
8, and is rotatably provided around the axis. A crank lever 60 to which the parking brake operating force is transmitted is attached to one end of the rotating shaft 56 located outside the protrusion 22 in a relatively non-rotatable manner, and a longitudinally intermediate portion of the rotating shaft 56 The rotating shaft 5 is located at an eccentric position.
A groove 62 is formed that extends over a predetermined length in a direction parallel to the six axes. In this embodiment, the crank lever 60 corresponds to a parking brake operating member. On the other hand, the adjusting bolt 3
A V-groove 64 is formed on the distal end surface of the head 34 of No. 6, the width of which becomes wider as the distance from the male threaded portion 32 increases. Between the groove 62 and the V-groove 64, a toggle 66 having a rectangular flat plate shape is formed. is inserted in a state in which rotation in a direction perpendicular to the plate surface is prevented. As a result, the adjustment bolt 36 is prevented from rotating around the axis by the toggle 66.

Next, the operation of the disc brake configured as above will be explained.

When the parking brake operating force is applied and the crank lever 60 is rotated counterclockwise in FIG.
A thrust is generated, and that thrust is applied to the adjusting bolt 3.
6. Piston 18 via adjuster nut 42
When the piston 18 is pushed out, one of the pads 28 is pressed against the disc rotor 10, and the reaction force pushes the caliper 12.
is moved in the opposite direction to the protruding direction of the piston 18, and the other pad 26 is pressed against the disk rotor 10 by the claw portion 24. As a result, the disc rotor 10 is compressed and braking is performed using the parking brake. When operating the parking brake, adjust the adjustment nut 4.
A rotation force in a direction opposite to the one direction is applied to the adjusting nut 42, but the rotation of the adjuster nut 42 in the opposite direction to the one direction is prevented by the leaf spring 46. When the parking brake operating force is released, the adjustment bolt 36 and adjustment nut 42 are tightened according to the biasing force of the spring 40.
is returned, and the piston 18 is returned to its original position by the returning action of the piston seal 53.

On the other hand, the piston 18 and the first cylinder bore 1
When hydraulic pressure is supplied to the liquid chamber formed by the piston 6 and the like, the piston 18 is pushed out and the disc rotor 10 is compressed in the same way as in the case described above, and braking by the service brake is performed. At this time, if the protrusion amount (movement amount) of the piston 18 does not exceed a predetermined amount, the piston 18
As the pads 26 and 28 protrude, no force is applied to the adjuster nut 42 through the annular member 48 and the thrust bearing 52 to rotate it in the one direction.
When the piston 18 and the piston seal 53 are ejected,
When slipping occurs between the piston 18 and the amount of protrusion of the piston 18 exceeding a predetermined amount, the piston 18 moves the flange portion 44 through the annular member 48 and the thrust bearing 52 to the head 34 of the adjuster bolt 36. By pushing the adjusting nut 42 in the direction away from the head 34, the adjusting nut 42 is rotated in the one direction while being rotated relative to the leaf spring 46, and is moved a predetermined distance in the direction away from the head 34. The play between the flange portion 44 of the thrust bearing 52 and the annular member 48 is determined in advance. Next, when the hydraulic pressure is released, the piston 18 is returned by the returning action of the piston seal 53 until the inner wall comes into contact with the outer peripheral surface of the flange portion 44 . As a result, the return position of the piston 18 is updated by the predetermined distance in the protrusion direction, and the pads 26, 28 and the disc rotor 10 are
The clearance between the two is automatically adjusted, and the amount of rotation of the crank lever 60 when operating the parking brake is automatically adjusted.

Here, in this embodiment, the one end portion of the leaf spring 46 is as shown in FIG. 1 and FIG.
A protrusion 68 that protrudes a predetermined distance in the outer circumferential direction, and a lock that extends a predetermined distance from the tip of the protrusion 68 in a direction intersecting the protrusion direction of the protrusion 68, in this embodiment, in one direction substantially perpendicular to the protrusion direction of the protrusion 68. Joint part 7
0, and in this engagement portion 70, the engagement groove 50 and the piston 18 are engaged with each other so as to be immovable relative to each other around the axis of the piston 18 and movable relative to each other in a direction parallel to the axis thereof. It is being As a result, the width dimension (L in FIG. 1) of the engagement groove 50 is slightly larger than the extension dimension of the engagement portion 70 and is sufficiently larger than the thickness of the leaf spring 46, so that the engagement groove 50 can be engaged. When forming the matching groove 50 by post-processing, the processability becomes even better.

Further, according to this embodiment, since the adjustment bolt 36 is prevented from rotating around its axis by the rectangular flat toggle 66, the head of the adjustment bolt 36 is connected to a plate integrally provided within the cylinder portion. Compared to the conventional case in which rotation of the adjusting bolt around its axis is prevented by being inserted into a through hole of a shaped member, there are advantages such as a reduction in the number of parts and the number of assembly steps.

Further, according to this embodiment, the thrust bearing 52 is inserted between the flange portion 44 and the annular member 48 with the predetermined play, and based on this play, the disk rotor 10 such as the pads 26, 28, etc. Since over-adjustment due to elastic deformation in the direction parallel to the axis can be prevented, there is no need to thread the adjustment bolt and the adjustment nut together with a predetermined play in the axis direction as in the conventional case. As a result, the adjuster bolt 36
Thickness dimension of screw teeth and adjuster nut 42
Since a sufficient dimension between the thread grooves can be ensured, the strength of engagement in the axial direction between the adjusting bolt 36 and the adjusting nut 42 during application of the parking brake can be suitably maintained.

In the above-mentioned embodiment, the protrusion 68 and the engagement part 70 are formed by simply bending one end of the leaf spring 46, which has the advantage of being easy to form. For example, as shown in FIGS. 3 and 4,
By making a U-shaped cut in one end of the leaf spring 46 and bending it, a pair of protrusions 72 and both protrusions 7 are formed.
Alternatively, as shown in FIG.
The protruding portion 76 and the pair of engaging portions 78 located on both sides of the protruding portion 76 may be formed by making L-shaped cuts in one end from both sides in the width direction and bending the protruding portion 76 .

Further, in the above-described embodiment, one end of the leaf spring 46 is engaged with the engagement groove 50 provided on the inner peripheral surface of the annular member 48, but this is not necessary; It may be engaged with a predetermined engagement groove provided directly on the surface.

Further, in the above-described embodiment, the toggle 66 is not necessarily necessary, and the crank lever 66
The adjusting bolt 36 may be directly pushed by the adjusting bolt 36.

In addition, various changes may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a main part of a cross section taken along line II in FIG. 2. FIG. 2 is a sectional view showing the main parts of a disc brake to which the present invention is applied. FIG. 3 is a diagram showing another example of the present invention, and corresponds to FIG. 1. FIG. 4 is an enlarged view of the leaf spring in FIG. 3 in the direction of arrow A. FIG. 5 is a diagram showing still another example of the present invention, and corresponds to FIG. 4. 12... Caliper, 18... Piston, 20...
...Cylinder part, 36...Adjustment bolt, 42
...adjust nut, 46...plate spring, 48...
... Annular member, 50 ... Engagement groove, 60 ... Crank lever (parking brake operating member), 68,
72, 76... protruding portion, 70, 74, 78... engaging portion.

Claims (1)

[Scope of Claim for Utility Model Registration] A bottomed cylindrical piston fitted in the cylinder part of the caliper is screwed to an adjustment bolt that is reciprocated in the axial direction in connection with the operation of the parking brake operating member. A disc brake equipped with a parking brake function that is pushed out through an adjusting nut and allows rotation of the adjusting nut in only one direction due to frictional resistance between the adjusting nut and a clutch spring wound around its outer circumferential surface. On the inner circumferential surface of the piston or on the inner circumferential surface of an annular member integrally provided on the inner circumferential surface of the piston,
An engagement groove extending in a direction parallel to the axis of the piston is provided, and the clutch spring is formed of a plate spring bent into a substantially annular shape, and a protrusion protrudes toward the outer circumference at one end of the plate spring. a portion extending a predetermined distance from the tip of the protruding portion in a direction intersecting the protruding direction of the protruding portion, and being unable to rotate relative to the engagement groove and the piston about the axis thereof, and relative movement in a direction parallel to the axis; A disc brake equipped with a parking brake function, characterized by being integrally provided with an engaging part that can be engaged.