JPH0354986Y2 - - 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 piston fitted in a cylinder portion of a caliper is pushed out through 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, and the adjustment nut and its Disc brakes are known that have a parking brake function in which the adjustment nut is allowed to rotate in only one direction due to the frictional resistance between it and a clutch spring wound around the outer circumferential surface. The frictional resistance between the adjuster nut and the clutch spring is normally ensured based on the elastic return force of the clutch spring in the inner circumferential direction.

Problems to be solved by this invention However, it is relatively difficult to ensure sufficient frictional resistance based only on the elastic restoring force of the clutch spring, and the rotation of the adjuster nut in the opposite direction is ensured. There were some cases where it was impossible to prevent this.

Means for Solving the Problems The present invention was developed against the background of the above circumstances, and its purpose is to develop a technology to ensure sufficient frictional resistance between the clutch spring and the adjustment nut. It is about providing. In order to achieve this object, the present invention provides a disc brake having a parking brake function as described above, in which the clutch spring and the adjustment nut are each made of a ferromagnetic material, and at least one of them is made of a ferromagnetic material. It is characterized by being magnetized.

In this way, since the clutch spring and the adjuster nut are each made of a ferromagnetic material and at least one of them is magnetized, the frictional resistance can be reduced based only on the elastic return force of the clutch spring. The frictional resistance can be further increased in response to the magnetic attractive force between the clutch spring and the adjuster nut than in the case where the frictional resistance is secured. Thereby, rotation of the adjuster nut in the opposite direction to the one direction can be prevented more reliably.

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

FIG. 1 is a diagram showing the main parts of a disc brake equipped 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 protrusion 22 adjacent to and approximately concentrically with the first cylinder bore 16 .
0, an adjusting bolt 36 having a male threaded portion 32 and a head 34 with a larger diameter is inserted into the head 3 with the male threaded portion 32 located inside the piston 18.
4, they are fitted so that they can move relative to each other in the axial direction. The adjustment bolt 36 is always urged in a direction away from the piston 18 by a spring 40 interposed between its head 34 and a washer 38 that is integrally provided on the inner peripheral surface of the first cylinder bore 16. An adjusting nut 42 made of a ferromagnetic material such as ferrous metal is screwed into the male threaded portion 32. A flange portion 44 protruding toward the outer circumference is provided at the end of the adjusting nut 42 located on the distal end side of the male thread portion 32.
2 is formed on the outer circumferential surface of the flange portion 44, and the tapered surface thereof is brought into contact with the tapered inner wall of the piston 18 in the direction in which the piston 18 protrudes. The outer circumferential surface of the adjuster nut 42 and the head 34 from the flange portion 44
A plate spring 46, which is curved into a substantially annular shape and has one end projecting a predetermined distance toward the outer periphery, is fitted into the side portion with a predetermined frictional resistance. This leaf spring 46 constitutes the clutch spring of this embodiment. On the other hand, on the inner circumferential surface of the piston 18 and at a position corresponding to the leaf spring 46, a non-ferrous metal such as copper or aluminum having an approximately oval outer circumferential shape is provided, facing the flange portion 44 in the axial direction. An annular member 48 made of (paramagnetic or diamagnetic material) is integrally fixed by caulking. A notch 50 is formed in the inner circumferential surface of the annular member 48 and extends in a direction parallel to the axis.
0, one end of the leaf spring 46 is engaged with the plate spring 46 so as to be non-rotatable about the axis and movable relative to the axis parallel to the axis. As a result, the leaf spring 46 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 frictional resistance, etc. are thus determined in advance. A thrust bearing 5 is provided between the flange portion 44 and the annular member 48 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.
2 is inserted. In addition, 53 is the piston 1
This is a piston seal that liquid-tightly seals between the piston 8 and the first cylinder bore 16 and also serves to return the piston 18.

Inside the protruding portion 22 , 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 communicates with the second cylinder bore 30 . The through hole 54
A rotary shaft 56 is provided inside the rotary shaft 56 so as to be rotatable about its axis via a bearing 58 . 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 An engagement groove 62 is formed at an eccentric position and extends over a predetermined length in a direction parallel to the axis of the rotating shaft 56. In this embodiment, the crank lever 60 corresponds to a parking brake operating member. On the other hand, the head 34 of the adjusting bolt 36
A V-groove 64 is formed on the distal end surface thereof, the width of which becomes wider as the distance from the male threaded portion 32 increases, and between the engagement groove 62 and the V-groove 64, a toggle 66 having a rectangular flat plate shape is formed on the plate surface. It is inserted in such a way that rotation in a direction perpendicular to 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 disk 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 amount of protrusion (amount of movement) 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 a slip 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 leaf spring 4 away from the adjusting nut 42,
6 is applied, and the adjusting nut 42 is rotated in the one direction and moved a predetermined distance in a direction away from the head 34. Thrust bearing 5
The play between the two flange portions 44 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 contacts 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 leaf spring 46
is made of a ferromagnetic material such as ferrous metal and is magnetized. As a result, since the adjusting nut 42 is made of a ferromagnetic material such as a ferrous metal, the leaf spring 46 is attracted toward the outer peripheral surface of the adjusting nut 42 with a predetermined magnetic attraction force. In this case, since the annular member 48 located close to the leaf spring 46 on the opposite side of the adjuster nut 42 is made of nonferrous metal such as copper or aluminum as described above, the leaf spring 46
And the adjuster nuts 42 are suitably magnetically attached to each other. As a result, compared to the conventional case where the frictional resistance between the clutch spring and the adjusting nut is ensured based only on the elastic return force of the clutch spring, the frictional resistance is further increased in accordance with the attractive force. Thus, rotation of the adjuster nut 42 in the opposite direction to the one direction is more reliably prevented.

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 the adjustment bolt is prevented from rotating 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-described embodiment, the leaf spring 46 made of ferromagnetic material is magnetized, but this is not necessarily necessary, and the adjuster nut 4 made of ferromagnetic material is
2 may be magnetized, or both may be magnetized.

Further, in the above-mentioned embodiment, the leaf spring 46 is used as the clutch spring, but this is not necessarily necessary, and the effects of the present invention can also be obtained even when a torsion coil spring is used, for example. .

Further, in the above-described embodiment, the annular member 48 is made of a non-ferrous metal, but it may be made of a ferrous metal if there is a relatively large distance between the annular member 48 and the leaf spring 46.

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 the drawing]

FIG. 1 is a sectional view showing the main parts of a disc brake to which the present invention is applied. 12... Caliper, 18... Piston, 20...
...Cylinder part, 36...Adjustment bolt, 42
... Adjustment nut, 46 ... Leaf spring (clutch spring), 60 ... Crank lever (parking brake operating member).

Claims (1)

[Scope of Claim for Utility Model Registration] A piston fitted into the cylinder part of a caliper is pushed out via an adjustment nut screwed into an adjustment bolt that is reciprocated in the axial direction in connection with the operation of a parking brake operating member. In a disc brake equipped with a parking brake function, the adjustment nut is allowed to rotate in only one direction due to frictional resistance between the adjustment nut and a clutch spring wound around the outer circumferential surface of the clutch spring. and a disc brake with a parking brake function, characterized in that each of the adjusting nuts is made of a ferromagnetic material, and at least one of them is magnetized.