JPH0989013A - Disk brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk brake device capable of attaining good braking performance. SOLUTION: Calmpers 34 and 36 are arranged in both ends of a disk rotor 30 in its diameter direction and a pressing force applied to the disk rotor 30 by brake pads 42 and 44 is distributed symmetrically with respect to the center of the disk rotor 30. Thus, moment applied to the disk rotor 30 for rotating the disk rotor by using a shaft passed through its rotational center and extended in its diameter direction as a supporting shaft is zero and the inclination of the disk rotor 30 is prevented. Thus, a reduction in a braking force is prevented. Further, since it is not necessary to arrange the calipers 34 and 36 in the outside of the outer periphery of the disk rotor 30 and a distance (r) from its center is made longer, a braking force is increased.

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, and more particularly to a disc brake device capable of exhibiting a high braking force.

[0002]

2. Description of the Related Art A vehicle is provided with a brake device for braking the vehicle. As one type of braking device,
Disc brake devices have been conventionally known. Such a disc brake device is generally configured to apply a braking force to a wheel by pressing a disc rotor fixed to the wheel from both sides with a pair of brake pads provided on a caliper. When the pressing force is constant, the braking force of the disc brake device increases in proportion to the distance between the portion where the pressing force acts on the disc rotor and the rotation center of the disc rotor. Therefore, in order to obtain a large braking force, it is desirable that the disk rotor has a large diameter so that a pressing force can be applied to a portion away from the rotation center of the disk rotor.

However, according to the structure of the conventional disc brake device described above, it is necessary to dispose the caliper so as to sandwich the outer edge portion of the brake pad. Therefore, the diameter of the disc rotor is limited in order to secure a space for arranging the caliper outside the outer peripheral portion of the disc rotor within the limited space of the inner peripheral portion of the wheel.

On the other hand, Japanese Patent Laid-Open No. 2-209634 discloses a disc brake device having a structure in which only one side of the disc rotor is pressed by a brake pad. According to this structure, since it is not necessary to sandwich the disc rotor between the brake pads, it is not necessary to dispose the caliper outside the outer peripheral portion of the disc rotor. Therefore, the diameter of the wheel disc is not subject to the above-mentioned restrictions.

[0005]

However, Japanese Patent Application Laid-Open No.
In the disc brake device disclosed in JP-A-209634, only one pressing portion is provided to the disc rotor. Therefore, when a pressing force is applied to the disk rotor from the pressing portion, the disk rotor receives a moment to rotate the disk rotor about a shaft that passes through the rotation center and extends in the radial direction. To work. When such a moment is generated, the disc rotor is tilted due to the pressing force of the brake pad,
The braking force may decrease. In this respect, the above-mentioned conventional disc brake device is not an optimal structure for realizing a large braking force.

The present invention has been made in view of the above points, and a large braking force is obtained by maximizing the diameter of the disc rotor, and the braking force is reduced due to the inclination of the disc rotor. It is an object of the present invention to provide a disc brake device that does not have any problems.

[0007]

The above object is to provide a disk brake in which a friction material is pressed only on one side surface of the disk rotor, with a plurality of pressing force generating means being provided.
Generated by each of the plurality of pressing force generating means,
A disk in which the plurality of pressure generating means are arranged so that the total sum of the moments for rotating the disk rotor about an axis passing through the rotation center of the disk rotor and extending in the radial direction thereof as a spindle is zero. Achieved by braking.

In the present invention, the braking force is generated by applying one side surface of the friction material by the pressure generating means. The pressing force generated by each pressing means generates a moment to rotate the disk rotor about a shaft that passes through the center of rotation of the disk rotor and extends in the radial direction thereof. Here, the pressing force generating means is arranged so that the total sum of the moments becomes zero. Therefore, the disk rotor does not tilt due to the pressing force applied by the friction material. Further, the caliper is arranged so that the pressing force of the friction material is applied to one side surface of the disk rotor. Therefore, it is not necessary to dispose the caliper outside the outer peripheral portion of the disc rotor.

[0009]

1 is a partial sectional view of a vehicle wheel equipped with a disc brake device according to an embodiment of the present invention. The rotation support member 10 is a disk-shaped flange 12
And a substantially cylindrical shaft portion 14. The flange 12 is provided at one end (the right end in FIG. 1) of the rotation support member 10 and is fixed to the vehicle body. The shaft portion 14 of the rotation support member 10 is formed with a large diameter portion 14a provided at a portion adjacent to the flange 12 and a small diameter portion 14b provided at an end portion opposite to the flange 12. Shaft 1
The connecting portion between the large diameter portion 14a and the small diameter portion 14b of No. 4 is formed in a tapered shape. The outer peripheral surface of the large diameter portion 14 a of the shaft portion 14 is fitted to the inner peripheral surface of the inner race of the bearing 16. The outer peripheral surface of the small diameter portion 14b is fitted to the inner peripheral surface of the inner race of the bearing 18.

The axle hub 20 is a cylindrical portion 20 having a substantially cylindrical shape.
a. The outer peripheral surface of the outer race of the bearing 16 is fitted to the inner peripheral surface of the vehicle body side end portion (right end portion in FIG. 1) of the cylindrical portion 20a, and the end portion opposite to the vehicle body (left end portion in FIG. 1). Bearing) on the inner surface of
The outer peripheral surface of the outer race 8 is fitted. Cylindrical part 2
An oil seal 19 is fitted between the end portion of the inner peripheral surface of the vehicle body 0a on the vehicle body side and the large diameter portion 14a of the shaft portion 14 of the rotation support member 10. Further, a grease cap 21a is fitted on the inner peripheral surface of the end portion of the axle hub 20 on the vehicle exterior side. The oil seal 19 and the grease cap 21a prevent water and dust from entering the sliding portions of the bearings 16 and 18 from the outside.

A collar-shaped hub flange portion 22 is provided on the outer peripheral portion of the axle hub 20. Hub flange 2
Hub nut 2 on the outside of the vehicle body (left side in FIG. 1)
The wheel 26 is fixed by 4. Wheel 2
The hub ornament 21 is fitted to the outer peripheral surface of the fitting portion of the axle hub 6 of FIG. Further, the hub flange portion 2
A disc rotor 30 is fixed to the inner side of the vehicle body 2 by a mounting bolt 28.

The disk rotor 30 is a disk-shaped member,
An annular braking surface 32 that protrudes toward the inside of the vehicle body is formed on the peripheral portion thereof. Inside the vehicle body of the braking surface 32,
The calipers 34 and 36 are arranged so that a symmetrical positional relationship is formed with respect to the central axis of the disk rotor 30. These calipers 34 and 36 are both the rotation support member 1
It is fixed to the vehicle body through a 0 flange 12.

The calipers 34, 36 are respectively hydraulic actuators 38, 40 and brake pads 42, 44.
It has. The hydraulic actuators 38 and 40 include hydraulic cylinders and hydraulic pistons. When the brake pedal of the vehicle is depressed, hydraulic pressure corresponding to the amount of depression is equally applied to the hydraulic actuators 36 and 38,
The hydraulic piston is driven axially. Brake pad 4
Reference numerals 2 and 44 are, for example, cylindrical friction materials, which are fixed to the hydraulic pistons of the hydraulic actuators 42 and 44, respectively. One end surface of the brake pads 42, 44 (see FIG.
In the left end surface), the braking surface 32 is separated by a small gap.
Facing.

According to the configuration of the disc brake device as described above, both the wheel 26 and the disc rotor 30 rotate integrally with the axle hub 20 with the rotation support member 10 as the rotation axis when the vehicle is running. When the driver depresses the brake pedal, the brake pads 42 and 44 are displaced toward the braking surface 32 of the disc brake 30. And
When the amount of displacement exceeds the width of the above-mentioned gap, the brake pads 42 and 44 come into contact with the braking surface 32. as a result,
The brake pads 42 and 44 are pressed toward the braking surface 32 with equal forces corresponding to the amount of depression of the brake pedal. At this time, the braking surface 32 and the brake pad 42,
The frictional force generated between the wheels 44 acts as a braking moment on the wheel 26.

As described above, in the structure in which only one surface side of the disk rotor is pressed by the brake pad, the disk rotor is rotated about the axis passing through the center of rotation of the disk rotor and extending in the radial direction. A moment to act acts. When such a moment acts, the disc rotor is tilted in the pressing direction by the brake pad. When such an inclination occurs, the pressing force acting between the brake pad and the disc rotor decreases, and the braking force decreases.

On the other hand, in this embodiment, the brake pads 42 and 44 are provided symmetrically with respect to the central axis of the disc rotor 30 and are pressed with equal pressing forces. In this case, the moment caused by the pressing force acting on the brake pad 42 and the brake pad 4
The moment caused by the pressing force acting on No. 4 cancels each other out and becomes zero. As a result, the disk rotor 3
The reduction of the braking force due to the inclination of 0 is prevented.

By the way, the pressing force of the brake pads 42, 44 on the braking surface 32 is F, the friction coefficient between the brake pads 42, 44 and the braking surface 32 is μ, and the brake pad 4 is
The distance between the center of 2,44 and the center of rotation of the wheel 26 is r
Then, the braking moment N acting on the wheel 26
Is N = 2 · μ · F · r. Therefore, a large braking force can be obtained by setting r to be large.

In this embodiment, the brake pad 4
It is not necessary to dispose the calipers 34 and 36 outside the outer peripheral portion of the disk rotor 30 because the reference numerals 2 and 44 press the braking surface 32 of the disk rotor 30 from only one side thereof. Therefore, as shown in FIG. 1, by disposing the calipers 38, 40 at both diametrical ends of the disc rotor 30, the centers of the calipers 38, 40 and the disc rotor under the predetermined diameter L of the disc rotor are arranged. The distance r from the center of can be set to the maximum. As a result, the braking moment N with respect to the predetermined pressing force F can be maximized.

FIG. 2 is a block diagram of a vehicle wheel portion equipped with a disc brake device according to a second embodiment of the present invention. In the figure, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. The disc brake device of the present embodiment is characterized in that the disc rotor 60 is mounted on the outside of the vehicle body of the hub flange portion 52 (on the left side in FIG. 5). The position of the pressing portion of the disc rotor 60 by the brake pads 42, 44 is configured to be the same as that of FIG. 1 by providing the disc rotor 60 with an annular bending portion and forming one step. The hub bolt 54a penetrates the disc rotor 60 and the wheel 26 and is screwed to the hub flange 52. As a result, the disc rotor 60 and the wheel 26
Are fixed to the hub flange 52.

According to this structure, by removing the hub nut 54, the disk rotor 60 together with the wheel 26 is removed.
Can be removed. Therefore, the wear of the disc rotor 60 progresses, and the workability when the disc rotor 60 is replaced is facilitated. Further, since the distance from the center of rotation of the disc rotor 60 to the pressing portion is kept the same as in FIG. 1, a large braking force similar to that of the first embodiment can be obtained.

FIG. 3 is a block diagram of a vehicle wheel unit equipped with a disc brake according to a third embodiment of the present invention. In the figure, the same components as those in FIG. 1 or 2 are designated by the same reference numerals, and the description thereof will be omitted. In the disc brake device of this embodiment, the disc rotor 70 is mounted on the opposite side of the hub flange 52 from the vehicle body (on the left side in FIG. 3), and the disc rotor 70 is mounted on the vehicle body more than the disc rotor 30 of FIG. It is characterized in that the calipers 34, 36 are arranged on the outer side of the vehicle body as compared with the positions in FIG. 1 by the distance arranged on the outer side.

With this construction, the disk rotor 60 can be easily replaced as in the case of the second embodiment, and the amount of protrusion of the calipers 34, 36 from the wheel portion toward the vehicle body can be reduced. Wheel 26 to be reduced
The space inside the car body is expanded. Therefore, it is possible to improve the degree of freedom in arranging the suspension mechanism or the like for connecting the flange 12 to the vehicle body. As a result, for example, the kingpin offset can be shortened.

In the first to third embodiments described above, as shown in FIG. 4, the disk rotor 30 is provided with two symmetric parts with respect to the center thereof, as shown in FIG. Are set to be equal to each other, so that the moment that tries to rotate the disk rotor about the axis passing through the center of rotation of the disk rotor and extending in the radial direction is canceled out. However, the present invention is not limited to this, and the plurality of pressing means may be arranged so that the sum of the above moments due to the pressing force generated by them is zero. That is, as shown in FIG. 5, pressing portions having the same pressing force may be provided symmetrically with respect to the center of the disk rotor at three or more positions, thereby canceling the above moment. Alternatively, FIG.
As shown in, the site for applying the pressing force F is provided in one place,
Furthermore, the moment may be canceled by providing two or more portions that apply a pressing force f smaller than F so as to generate a moment that balances the moment generated by the pressing force. .

In the above first to third embodiments,
The brake pads 42 and 44 correspond to the above-mentioned friction material, and the calipers 34 and 36 correspond to the above-mentioned pressing means, respectively.

[0025]

As described above, according to the present invention, a disk acting as a spindle, which acts on the disk rotor, passes through the center of rotation of the disk rotor, and extends in the radial direction, is a spindle. Since the moment that attempts to rotate the rotor becomes zero, it is possible to prevent the braking force of the disc brake device from decreasing due to the inclination of the disc rotor. Further, since the caliper can be disposed on one side of the disc rotor, the diameter of the disc rotor can be set large without being restricted by the disposition of the caliper. Thereby, a large braking force can be obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a wheel equipped with a disc brake device according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a wheel equipped with a disc brake device according to a second embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a wheel equipped with a disc brake device according to a third embodiment of the present invention.

FIG. 4 is a model diagram showing a disc rotor pressing method in the disc brake devices of the first to third embodiments.

FIG. 5 is a model view showing another method of pressing the disc rotor of the disc brake device.

FIG. 6 is a model diagram showing still another method of pressing the disc rotor of the disc brake device.

[Explanation of symbols]

 30, 60, 70 Disc rotor 34, 36 Caliper 42, 44 Brake pad

Claims (1)

[Claims] 1. A disc brake in which a friction material is pressed only on one side surface of a disc rotor, the disc brake includes a plurality of pressing force generating means, and each of the plurality of pressing force generating means generates the pressing force.
The plurality of pressing generating means are arranged so that the total sum of the moments for rotating the disk rotor about the shaft passing through the center of rotation of the disk rotor and extending in the radial direction as a spindle is zero. Disc brakes featuring.