JPH0814280A - Disc brake - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a disc brake that automatically corrects the mismatch between the disc rotor surface and the pressing surface of the brake pad. [Structure] Disc rotor 31 and brake pad 1
The disc brake 1 includes the brake calipers 20 and the brake calipers 20. The first brake pad 11 includes a contact piece 110 that contacts the disc rotor 31 and a contact piece 110.
And a pedestal 15 for holding. The piston 22 for pressing the pedestal 15 has a convex portion 220 (or a concave portion) at the top,
The pedestal 15 has a concave portion 1 that is in surface contact with the convex portion 220 in a freely slidable manner
It has 51 (or a convex part). Friction reducing means is provided on the contact surface between the concave portion 151 and the convex portion 220. Friction reducing means include grease and coating layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake used for braking a vehicle.

[0002]

2. Description of the Related Art Disc brakes are provided on both sides of a disc rotor that rotates integrally with an object to be braked, such as the wheels of an automobile, to press brake pads for braking. That is, as shown in FIG. 5, in the disc brake 90, the brake pads 92 are arranged on both sides of the disc rotor 91, and the brake caliper 93 is operated to press the brake pad 92 against the disc rotor 91 for braking.

The brake caliper 93 has a piston 931 for driving the brake pad 92 and a cylinder 932 for accommodating the piston 931. However, due to wobbling of the disc rotor 91, for example, the surface 911 of the disc rotor 91 and the pressing surface 921 of the brake pad 92 are
There is a problem in that the parallelism between the two and the so-called “mismatch” occurs, and the braking characteristics are changed (illustrated by the broken line in the figure).

That is, as shown in FIG. 5, a deviation angle Δθ occurs between the perpendicular 991 to the disc rotor surface 911 and the axial center 992 of the piston 931 in the broken line display. In this state, the pressing surface 921 of the brake pad 92 is It will not be pressed parallel to the disc rotor surface 911.

Therefore, as shown in FIG.
There has been proposed a method in which a curved concave portion 933 is formed on the top of No. 1 and a brake pad 92 is swingably attached to the concave portion 933 to correct the influence of the deviation angle Δθ.
4-23248).

That is, the convex portion of the pedestal 922 of the brake pad 92 is brought into surface contact with the concave portion 933 provided on the top of the piston 931 so as to be swingable. Then, by swinging the pedestal 922, the pressing surface 92 of the brake pad 92 is
1 is pressed parallel to the disc rotor surface 911. In addition,
FIG. 5 shows an example of a so-called floating type caliper in which one set of piston and cylinder is provided, but the same applies to an exposed cylinder type in which two sets of piston and cylinder are provided.

[0007]

However, the conventional disc brake 90 shown in FIG. 5 has the following problems. It strengthens the driving force of the brake caliper 93, and at high pressure, the piston 931 causes the pedestal 922 of the brake pad 92.
That is, when is pressed, the correction effect of the deviation angle Δθ is reduced.

As a result, the pressing surface 9 of the brake pad 92
21 and the disk rotor surface 911 become incompletely parallel, uneven wear and the like occur, and the braking force decreases. In view of such conventional problems, the present invention is to provide a disc brake capable of satisfactorily correcting the misalignment between the disc rotor surface and the pressing surface of the brake pad.

[0009]

DISCLOSURE OF THE INVENTION The present invention is a disc having a disc rotor connected to an object to be braked, brake pads arranged on both sides of the disc rotor, and a brake caliper for pressing the brake pad against the disc rotor. A brake, wherein the brake pad has a contact piece that comes into contact with the disc rotor and a pedestal that holds the contact piece, while the brake caliper has a piston that presses the pedestal of the brake pad, And a cylinder for accommodating the piston, wherein the top of the piston for pressing the pedestal is formed with a curved concave portion or convex portion,
On the other hand, the pedestal is formed with a convex portion or a concave portion that is slidably in surface contact with the concave portion or the convex portion. In the disc brake, the contact surface between the concave portion and the convex portion is provided with friction reducing means for reducing frictional resistance between the both.

What is most noticeable in the present invention is that the pedestal of the brake pad is mounted on the top of the piston, and the top of the piston is formed with a curved concave portion or convex portion for pressing the pedestal, and A convex portion or a concave portion that comes into surface contact with the concave portion or the convex portion is provided, and friction reducing means is provided on the contact surface between the concave portion and the convex portion.

As the friction reducing means, there is, for example, one in which a low friction material such as grease or lubricant is interposed on the contact surface. In this case, it is preferable that a recess for holding the low friction material is further provided on the contact surface. By providing such a depression, the low-friction material can be held on the contact surface for a long time, and the operation time of the friction reducing means can be prolonged. Examples of depressions include a pit (recess) for storing grease and a ring-shaped groove.

As another example of the friction reducing means, there is a method of forming a coating layer of a low friction material on the contact surface. There is also a friction reducing means for reducing friction resistance by mirror-finishing the contact surface. When these examples of the friction reducing means are used together, a more excellent friction reducing effect can be obtained.

The diameter of the caliper piston is P
And the radius of curvature R on the contact surface is 0.75
It is preferable to set the value between P and 1.5P to form a substantially uniform curvature. This is because if the radius of curvature R is larger than 1.5P, the correction effect of the deviation of the piston axial center (the deviation angle Δθ) with respect to the disk rotor surface becomes weak, while
If the radius of curvature R is smaller than 0.75P, the above deviation (Δ
This is because when (θ) occurs, the slip resistance of the contact surface between the concave portion and the convex portion becomes large, the swing of the brake pad is suppressed, and the shift correcting action is similarly reduced. Therefore, the radius of curvature R is appropriately between 0.75 and 1.5P.

[0014]

As described above, in the disc rotor 90 shown in FIG. 5, when the driving force of the brake caliper 93 is increased, the axial center of the piston 931 is deviated (the disc rotor surface 911 and the pressing surface 921 of the brake pad 92). Inconsistency) of the above) is reduced. The inventor has pursued the cause of the decrease in the above-mentioned correction effect, and has clarified that one of the major causes thereof is an increase in the slip resistance at the contact surface.

In the disk rotor of the present invention, friction reducing means is provided on the contact surface between the concave or convex portion of the piston and the convex or concave portion of the brake pad pedestal.
Therefore, the slip resistance at the contact surface can be reduced. As a result, even if the driving force of the brake caliper (piston) is increased, it is possible to suppress a decrease in the correction function of the piston axial misalignment.

As described above, according to the present invention, it is possible to provide a disc brake which can satisfactorily correct the misalignment between the disc rotor surface and the pressing surface of the brake pad.

[0017]

【Example】

Embodiment 1 A disc brake according to an embodiment of the present invention will be described with reference to FIGS. In this example, as shown in FIG. 1, a disc rotor 31 connected to an object to be braked, first and second brake pads 11 and 14 arranged on both sides of the disc rotor 31, and brake pads 11 and 14 are provided. The disc brake 1 includes a brake caliper 20 that is pressed against the disc rotor 31.

The first brake pad 11 has a contact piece 110 that comes into contact with the disc rotor 31, and a pedestal 15 that holds the contact piece 110, while the brake caliper 2 is provided.
Reference numeral 0 has a piston 22 that presses the pedestal 15 of the first brake pad 11, and a cylinder 21 that houses the piston 22.

A piston 22 for pressing the pedestal 15
A convex portion 220 having a curved shape is formed on the top of the pedestal 15
A concave portion 151 that comes into surface contact with the convex portion 221 of the piston 22.
Has been formed. The radius of curvature of the concave portion 151 is slightly larger than the radius of curvature of the convex portion 221. Further, the contact surface between the concave portion 151 and the convex portion 220 is provided with friction reducing means for reducing the frictional resistance between the both 151 and 220. The friction reducing means interposes grease on the contact surfaces of the concave portion 151 and the convex portion 220. The concave portion 151 and the convex portion 220 are formed in the depression 15 for holding the grease.
2,153,221.

Each of these will be described in detail below. In this example,
This is a disc brake 1 for an automobile, and a disc rotor 31 is connected to wheels (not shown). The brake caliper 20 is a floating type, in which hydraulic oil is press-fitted into the base end side of the piston 22, and the piston 22 is moved to the first brake pad 1
Press toward 1. The cylinder 21 presses the second brake pad 14 from the opposite side to the disc rotor 31 by the reaction force of pressing the first brake pad 11 to the disc rotor 31 by the piston 22.

That is, as shown in FIG. 1, the second brake pad 14 has a back metal 141 that contacts the cylinder 21 and a contact piece 140 that contacts the disc rotor 31. The cylinder 21 presses the second brake pad 14 against the disk rotor 31 by the reaction force applied to the disk rotor 31.

A convex portion 220 having a gentle and uniform curvature is formed on the top of the piston 22 for pressing the first brake pad 11, and a concave portion 221 for storing grease is provided at the center of the convex portion 220. There is. The radius of curvature of the convex portion 220 is 66 mm, and the diameter of the piston 22 is about 1.
It is 1 time.

The first brake pad 11 has a contact piece 110 for pressing the disc rotor 31 and a pedestal 15,
The pedestal 15 includes a back metal 159 for fixing the contact piece 110 and a ring plate 150. The ring plate 150 may be fixed to the back metal 159 or may not be fixed. The ring plate 150 has a recess 151 that comes into surface contact with the protrusion 220 of the piston 22.

In the recess 151, as shown in FIG. 2, a circular recess 15 in the central portion facing the recess 221 of the piston 22.
2 and a ring-shaped recess 153 formed near the outer periphery are formed, and grease is injected into the recesses 152 and 153. In FIG. 1, reference numeral 25 is a piston seal.

Next, the function and effect of the disc brake 1 of this embodiment will be described. In the disc brake 1 of this example, the contact surface (the convex portion 220, the concave portion 151) between the piston 22 and the first brake pad 11 is a curved surface having a gentle and uniform curvature. The convex portion 220 of the piston 22 and the concave portion 151 of the first brake pad 11 are in slidable surface contact.

Therefore, when the axial center of the piston 22 is not completely perpendicular to the pressing surface 311 of the disk rotor 31 (the deviation angle Δθ shown in FIG. 5 is generated), the first brake pad 11 pressed by the disk rotor 31. Slides and rotates along the contact surface to correct the deviation angle Δθ. As a result, the pressing surface 311 of the disc rotor 31 and the pressing surface 111 of the contact piece 110 of the first brake pad 11 are parallel to each other and come into full surface contact.

The contact surface (convex portion 220, concave portion 15)
In 1), since grease is interposed as a friction reducing means, the slip resistance at the contact surface is extremely small,
Therefore, even if a strong force acts on the contact surface, it does not hinder the sliding rotation of the first brake pad 11. Therefore, even when the piston 22 drives the first brake pad 11 with a strong force, the disc rotor surface 311 and the pressing surface 111 of the brake pad 11 are misaligned (deviation angle Δ).
θ) can be satisfactorily corrected.

The grease is recessed 152, 153,
Since it can be abundantly stored in 221, the correction effect can be maintained for a long period of time. As described above, according to this example, it is possible to provide the disc brake 1 that can satisfactorily correct the misalignment between the disc rotor surface 311 and the pressing surface 111 of the brake pad 11.

Embodiment 2 In this embodiment, as shown in FIG. 3, in Embodiment 1, a recess 230 is formed on the top of the piston 23, a protrusion 161 is provided on the pedestal 16 of the first brake pad 12, and a recess is formed. Two
This is another embodiment in which the depressions 231 and 162 provided in the projection 30 and the convex portion 161 are provided at one central position.

That is, a concave portion 230 is provided on the top of the piston 23, and a convex portion 161 that comes into surface contact with the concave portion 230 is provided on the first brake pad 12. Then, the concave portion 230 and the convex portion 1
Indentations 231 and 162 are provided in the central portions of 61, respectively. Others are the same as those in the first embodiment.

Example 3 This example is another example in which coating layers 241 and 172 of low-friction material are provided on the contact surface in the example 2 as shown in FIG. 4 and no grease is used. is there.
That is, in this example, the surface of the concave portion 240 of the piston 24 and the convex portion 171 of the pedestal 17 of the first brake pad 13 are arranged.
Coating layer 24 of low friction material on the surface of
1, 172 are formed.

Since no grease is used in this example, no depression is provided. Since the coating layers 241 and 172 are made of a low-friction material, it is possible to reduce the sliding resistance of the contact surfaces (the concave portions 240 and the convex portions 171) like the grease. Others are the same as in the second embodiment.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a disk rotor according to a first embodiment.

FIG. 2 is a side view of the ring plate of the brake pad according to the first embodiment.

FIG. 3 is a cross-sectional view of a main part of a disk rotor according to a second embodiment.

FIG. 4 is a sectional view of a main part of a disk rotor according to a third embodiment.

FIG. 5 is a sectional view of a main part of a conventional disc rotor.

[Explanation of symbols]

 1. . . Disc brake, 11, 12, 13. . . First brake pad, 110. . . Contact piece, 14. . . Second brake pad, 15, 16, 17. . . Pedestal, 151. . . Recess, 161, 171. . . Convex part, 20. . . Brake caliper, 22. . . Piston, 230, 240. . . Recess, 31. . . Disk rotor,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Ito 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (6)

[Claims] 1. A disc brake comprising: a disc rotor connected to an object to be braked; brake pads arranged on both sides of the disc rotor; and a brake caliper for pressing the brake pad against the disc rotor. The brake pad has a contact piece that contacts the disc rotor and a pedestal that holds the contact piece, while the brake caliper houses a piston that presses the pedestal of the brake pad and the piston. A cylinder, and a curved concave portion or convex portion is formed on the top of the piston for pressing the pedestal, while a convex portion that slidably makes surface contact with the concave portion or convex portion on the pedestal. Alternatively, a concave portion is formed, and the curved concave portion and the convex portion have a relation of the curvature radius of the concave portion ≧ the curvature radius of the convex portion, and the contact surface between the concave portion and the convex portion is A disc brake comprising friction reducing means for reducing frictional resistance between the both. 2. The disc brake according to claim 1, wherein the friction reducing means includes a low friction material such as grease or lubricant on at least one contact surface of the concave portion or the convex portion. . 3. The disc brake according to claim 2, wherein the friction reducing means has a recess for holding the low friction material in the concave portion or the convex portion. 4. The friction reducing means according to claim 1, wherein the friction reducing means has a coating layer of a low friction material formed on a contact surface of the concave portion or the convex portion. Disc brake to do. 5. The method according to any one of claims 1 to 4,
The disc brake, wherein the friction reducing means has a mirror-finished contact surface of the concave portion or the convex portion. 6. The method according to any one of claims 1 to 5,
The disc brake, wherein the contact surface of the concave portion or the convex portion is formed to have a substantially uniform curvature with a radius of curvature between 0.75P and 1.5P, where P is the diameter of the piston.