JP2002048162A - Disc brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disc brake device in which generation of unstable vibration is restrained and brake noise is surely reduced. SOLUTION: In the disc brake device which provides a travelling wheel with a braking force by pressing a disc rotor against a brake pad, the disc brake device is characterized in that the disc rotor is gripped by a plurality of pairs of the brake pad, wherein a brake pressing force per one pair of brake pad is lowered and the unstable vibration is restrained to generate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake device for braking by pressing a disc rotor, which rotates together with wheels, with a brake pad.

[0002]

2. Description of the Related Art In a disk brake device of an automobile, a motorcycle, a railroad vehicle, etc., a so-called brake squeal sometimes occurs, which generates a high-frequency noise during braking. The brake squeal phenomenon is caused by the natural frequency of the system consisting of the components of the brake pad and the pressing device constituting the disc brake and the bending of the disc rotor outside the nodal plane when the brake pad is pressed against and frictionally engaged with the disc rotor. When the vibration and the natural frequency of the longitudinal vibration in the plane approach each other and resonate, the vibration system becomes unstable self-excited vibration due to the nonlinearity of the friction coefficient of the sliding part, and brake squeal occurs. Things.

Therefore, for example, the natural frequency of the disk rotor is changed by changing the plate pressure of the sliding portion in Japanese Patent Application Laid-Open No. 10-78064 or by changing the length of graphite in the tissue in Japanese Patent Application Laid-Open No. 10-30663. Inventions have been provided that have been modified to reduce brake squeal. Japanese Patent Application Laid-Open No. 10-26159 discloses that a damping material is buried in a disk rotor or that a disk rotor is disclosed.
Japanese Patent No. 021435 discloses a device in which the provision of a frictional force generating member on a friction pad increases damping during vibration and reduces brake squeal. Furthermore, the ventilation part of the brake disk is improved.
Many countermeasures have been taken, such as a reduction in the excitation force of vibration due to thermal strain due to an improved mounting of the sliding plate to the disk rotor in JP 0410.

[0004]

However, such a technique cannot completely solve the brake noise, and a more effective measure for reducing the brake noise is desired. The present invention has been made in view of such a problem, and an object of the present invention is to provide a disc brake device that suppresses generation of unstable vibration and reliably reduces brake squeal.

[0005]

Means for Solving the Problems To achieve the above object, a first aspect of the present invention is a disk brake device which applies a braking force to wheels by pressing a disk rotor with a brake pad. The disk rotor is gripped by a plurality of pairs of brake pads. According to a second aspect of the present invention, there is provided the disk brake device according to the first aspect, wherein the disk rotor is fixed to a rim side of a wheel, and is gripped by a brake pad from inside the disk rotor. And

In the present invention, when the present inventor performed an analysis of a three-degree-of-freedom system sliding vibration corresponding to a brake pad pressed against a disk rotor with respect to brake squeal, the friction coefficient was reduced as shown in FIG. The vibration is stable in the positive-slope sliding speed region and decays with time.

[0007] On the other hand, in a slip speed region where the friction coefficient has a negative gradient, unstable vibration may occur. However, it has been found that when the natural frequency is constant, the vibration can be stabilized if the pressing force of the sliding portion is small or the friction coefficient is small. From the viewpoint that the unstable vibration corresponds to the brake squeal, the brake squeal can be reduced by reducing the pressing force of the sliding portion.

The present invention has been made on the basis of the above findings. As a method of reducing the pressing force of the sliding surface without changing the braking performance, a method of increasing the average diameter of the sliding surface of the disk rotor is described. By using a plurality of pairs of brake pads, it is possible to at least reduce the pressing force of one pair of brake pads. Thus, the occurrence of unstable self-excited vibration is suppressed, and a disk brake device with reduced brake squeal can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment in which the present invention is applied to a disc brake device for a two-wheeled vehicle will be described below with reference to the drawings. In FIG. 1, a front fork 1 of a motorcycle
The shaft 11 is fixed to the front end of the “0”. Reference numeral 20 denotes a wheel, which includes a wheel hub 24, a wheel rim 22 on which the tire 21 is fitted, and a cast wheel spoke 23 connecting the wheel hub 24 and the wheel rim 22. The wheel 20 is rotatably supported around the shaft 11 via a wheel hub 24.

Reference numeral 30 denotes a disk rotor. The disk rotor 30 is fixed to the rim side of the wheel spoke 23 and includes a flange 40 and a sliding plate 50. The flange 40 is a frusto-conical cylinder provided with a plurality of ventilation holes 44 (see FIG. 2) for cooling and weight reduction, and has a connection portion 42 with the sliding plate 50 on the inner diameter side, and an outer diameter. On the side, a wheel coupling portion 43 with a wheel spoke is provided.

As shown in FIG. 1B, a front brake pad 61 and a rear brake pad 6 are provided on both sides of the sliding plate 50.
The pair 2 is supported by the caliper 64. The caliper 64 is supported by the front fork 10 via a mounting bracket 63.
The brake pads 71, 72 are pressed against the sliding surface of the disk rotor 30 via backing plates 67, 68 by hydraulic pistons 65, 66 built in the disk rotor 3.
The rotation of 0 is stopped, and the wheel 20 is braked.

Further, with respect to the caliper 64, FIG.
As shown in the figure, another caliper 74 is supported by the front fork 10 via another mounting bracket 73 at another position in the circumferential direction of the disk rotor 30. The caliper 74 supports another pair of front brake pads 71 and a rear brake pad 72.
The same operation as the pair of brake pads 61 and 62 is performed. Two pairs of brake pads 61, 62 and 71, 72
Are arranged at a pitch of an angle θpp in the circumferential direction of the sliding surface as shown in FIG. On the other hand, the sliding plate 50 has annular sliding surfaces 52 and 53 on both front and back surfaces, has a through portion 54 on the inner diameter side of the sliding surface, and has a connecting portion 55 with the flange 40 on the outer diameter side. And is coupled to the collar 40.

In this embodiment, two pairs of brake pads 6 are provided.
1, 62 and 71, 72 are 90
Although the arrangement at the pitch of degrees is shown, the invention is not limited to this angle. That is, in the present embodiment, the sliding plate 50
The bending vibration of the disk rotor is predominant in the nodal diameter three vibration mode due to the tongue-like coupling portion 55 with the six protruding flanges 40, the pitch angle θd = 60 degrees of the six coupling bolts 56, and the shape of the flange 40. Is likely to appear. In the nodal diameter three vibration mode, the period between the nodal point and the antinode is 30 degrees, so that the distance between the two pairs of brake pads of this embodiment is 30 degrees.
Since the angle is set to 90 degrees, which is an odd multiple of degrees, the node and the antinode are pressed together at the time of vibration, and the arrangement is such that vibration in the node diameter 3 vibration mode is unlikely to occur. As described above, the arrangement of a plurality of pairs of pads selects an appropriate arrangement according to the shapes of the sliding plate and the flange.

As described above, by employing a plurality of pairs of brake pads, the pressing force per pair of brake pads can be reduced, and by appropriately disposing the plurality of pairs of brake pads, a specific nodal diameter vibration can be obtained. Mode vibration can be made less likely to occur, and as a result, unstable self-excited vibration is suppressed, and brake squeal is less likely to occur. In the present embodiment, by connecting the outer diameter side of the sliding plate 40 to the wheel spokes of the wheel, the average diameter of the sliding surfaces 52 and 53 is large, and the pad pressure contact force per pair can be further reduced.

The disk rotor 30 in the above embodiment
Can be integrated with the flange 40 and the sliding plate 50. In addition, the disk rotor 30 in the above embodiment is connected to the wheel spokes 23, but may be connected to a wheel plate or a wheel rim, including when the wheel spokes are made of wire. Therefore, in addition to the embodiment applied to the two-wheeled vehicle described above, the present invention can also be applied to a disc brake device of a four-wheeled passenger car, a four-wheeled lorry, and a railway vehicle.

It should be noted that the disk rotor 30 in the above embodiment can be connected to the wheel hub of the wheel on the inner diameter side of the sliding plate like a conventional disk rotor.
In this case, a plurality of pairs of brake pads are
Needless to say, it is necessary to grip from the outer peripheral direction of 0.

In the above description, a plurality of pairs of brake pads are provided before and after the front fork.
The present invention is not limited to this, and may be provided only before or after the front fork.

【The invention's effect】

According to the present invention, a plurality of pairs of brake pads press-grip a disk rotor to reduce the pressing force per pair of brake pads, thereby suppressing the occurrence of unstable self-excited vibrations. Reduce squeal. By properly arranging multiple pairs of brake pads, it is possible to reduce the occurrence of unstable self-excited vibration by reducing the occurrence of unstable self-excited vibration due to vibration of a specific nodal diameter vibration mode. .

According to a second aspect of the present invention, in the first aspect of the present invention, the disk rotor is fixed to the rim side of the wheel, and the disk rotor is gripped from inside of the disk rotor by a brake pad. In this way, it is possible to increase the average diameter of the sliding surface without lowering the natural frequency of the disk rotor, and to further reduce the pressure contact force per brake pad while maintaining the braking performance. To reduce brake squeal.

Increasing the average diameter of the sliding surface of a disk rotor fixed to the hub side of a wheel, which has been widely used in the past, has no particular problem in structure, but lowers the natural frequency. There is a problem that. Considering a disk that is approximately fixed at the center and is free at the periphery, the natural frequency of out-of-plane vibration is inversely proportional to the square of the diameter when the diameter increases,
Become smaller. More vibration modes are included in the natural frequency range related to brake squeal, and the effect of reducing the pressure contact force does not appear. Assuming that the disk rotor of the present invention is a disk fixed approximately at the periphery, for example, about 6 times in the nodal diameter 2-vibration mode and about 6 times in the nodal diameter 3-vibration mode as compared with a conventional center-fixed peripheral free disk. 4 times. The natural frequency of the disk rotor of the present invention having a sliding surface average diameter twice as large as the natural frequency of the conventional disk rotor supported on the inner diameter side should be approximately the same. Can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a front wheel portion which is an embodiment in which the present invention is applied to a two-wheeled vehicle. (A) is an overall sectional view, (b)
Is an enlarged view of a caliper portion.

FIG. 2 is a side view of a front wheel portion which is one embodiment in which the present invention is applied to a two-wheeled vehicle.

FIG. 3 shows a brake pad of a disk brake device according to an embodiment of the present invention, together with a sliding plate of a disk rotor. (A) is a side view, (b) is AA sectional drawing.

FIG. 4 is a diagram qualitatively illustrating a relationship between a friction coefficient of a sliding surface of a brake device and a slip speed.

[Explanation of symbols]

 30: Disc rotor 40: Flange 41: Conical cylinder 42: Ventilation hole 50: Sliding plate 52, 53: Sliding surface 54: Penetration portion 61, 62, 71, 72: Brake pad 63, 73: Mounting bracket 64, 74: caliper

Claims (5)

[Claims] 1. A disk brake device in which a brake force is applied to wheels by pressing a disk rotor with brake pads, wherein the disk rotor is gripped by a plurality of pairs of brake pads. Disc brake device. 2. The disk brake device according to claim 1, wherein the disk rotor is fixed to the rim side of the wheel, and is held by a brake pad from inside the disk rotor. 3. The disk brake device according to claim 1, wherein the disk rotor is fixed to the hub side of the wheel, and is held by a brake pad from outside the disk rotor. 4. The system according to claim 1, wherein a plurality of pairs of brake pads are provided before and after the front fork.
4. The disc brake device according to any one of claims 1 to 3. 5. The system according to claim 1, wherein a plurality of pairs of brake pads are provided before or after the front fork.
4. The disc brake device according to any one of claims 1 to 3.