JPS5913384Y2 - disc brake - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a disc brake that obtains braking force by pressing a rotating disc plate with a friction pad.

The friction surfaces against which the friction pads of the disc plate are pressed have different circumferential velocities in the radial direction.

Furthermore, during braking, the friction pad tends to slide against the disc plate at the rear in the rotational direction (so-called leading side) so as to stick to the disc plate.

For these reasons, friction pads experience uneven wear.

In conventional disc brakes, the outer diameter of a hydraulic piston that presses a friction pad and the inner diameter of a cylinder into which the hydraulic piston is fitted are uniform in the axial direction.

Therefore, when the hydraulic piston presses the unevenly worn friction pad toward the disk plate, the hydraulic piston receives a reaction force that is inclined with respect to the axis of the cylinder.

As a result, the hydraulic piston bites into the cylinder, and the hydraulic piston and cylinder become integral, resulting in a so-called brake lock condition.

If this phenomenon occurs while driving, the wheels will remain stationary, which is extremely dangerous.

Furthermore, in the production process, if a manufacturing worker accidentally inserts a hydraulic piston into a cylinder at an angle, the hydraulic piston will bite into the cylinder and become integrally fixed.

This phenomenon is significant when the length of the hydraulic piston is relatively short compared to its outer diameter.

A prior art technique for preventing such a phenomenon in which the hydraulic piston bites into the cylinder and the hydraulic piston and cylinder become integral is shown in FIGS. 3 and 4.

The disc plate 21 is pressed from both sides (left and right in FIGS. 3 and 4) by friction pads 22 to obtain braking force.

The friction pad 22 is fixed to a back metal 23.

The back metal 23 is connected to the hydraulic piston 24 from the left rear side in FIG.
This causes the friction pad 22 to be pressed against the disk plate 21.

By supplying pressure oil to the hydraulic chamber 27 of the cylinder 26, the hydraulic piston 24 is displaced to the right in FIG. 3 as described above.

A packing 28 is attached to the cylinder 26 in an annular manner.

The outer peripheral surface 29 of the hydraulic piston 24 is inclined at an angle θ with respect to the axis 30 thereof.

This prevents the hydraulic piston 24 from biting into the cylinder 26 and becoming integral with it even if the axis 30 of the hydraulic piston 24 undergoes angular displacement.

In the prior art shown in FIG. 3, the outer circumferential surface 29 of the hydraulic piston 24 is inclined so that the diameter becomes smaller as it moves away from the disk plate 21. If the gasket 28 protrudes due to a large displacement to the right in Figure 3 due to wear, etc.
is separated from the outer circumferential surface 29, and there is a risk that the pressure oil in the hydraulic chamber 27 will spout out.

If the pressure oil in the hydraulic chamber 27 were to blow out, the braking action would not be maintained at all, resulting in an extremely dangerous situation.

Further, such separation between the outer circumferential surface 29 of the hydraulic piston 24 and the packing 28 can also occur when the axis 30 of the hydraulic piston 24 is no longer perpendicular to the disk plate 21 and is angularly displaced.

In another prior art shown in FIG. 4, a hydraulic piston 24
The outer peripheral surface 29a of the hydraulic piston 24a is formed into an arc shape having a radius R from a center 31 located at a position offset from the axis 30 of the hydraulic piston 24a, and the outer shape of the piston 24a is drum-shaped.

Such a configuration prevents the hydraulic piston 24a from biting into the cylinder 26.

In this prior art, when the friction pad 22 wears out and the hydraulic piston 24a is largely displaced to the right in FIG.
8 may become separated from each other, which may cause the pressure oil in the hydraulic chamber 27 to leak, which is dangerous.

In order to prevent this, it is desirable to make the radius R as large as possible, but if this is done, the hydraulic piston 24a will easily bite into the cylinder 26.

An object of the present invention is to provide an improved hydraulic brake that prevents the hydraulic piston from biting into the cylinder and becoming one piece with the cylinder, and also prevents the pressure oil in the hydraulic chamber from leaking regardless of the displacement of the hydraulic piston. It is.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

This disc brake obtains braking force by pressing a disc plate 1 fixed to the hub of a two-wheeled vehicle from both sides with friction pads 2 and 3.

The friction pads 2 and 3 are fixed to back metals 4 and 5.

The back plates 4 and 5 are loosely inserted by a support pin 6 parallel to the axis of the disk plate 1, and are supported so as to be freely displaceable along the support pin 6.

A right cylindrical hydraulic piston 7.8 is positioned behind the back metals 4, 5 so as to press them from behind.

Hydraulic pistons 7.8 are housed in cylinders 9 and 10, respectively.

The cylinders 9, 10 are provided with gaskets 13, 14, respectively, which slide on the outer peripheral surface of the hydraulic piston 7.8 and keep the cylinders 9, 100 and the hydraulic chambers 11.12 liquid-tight.

FIG. 2 is an enlarged sectional view of section II of FIG. 1.

In the inner wall 15 of the cylinder 9, the inner wall portion 16 of the hydraulic chamber 11 is formed to have a larger diameter as it moves away from the position where the packing 13 is provided along the axis.

That is, in the state shown in the second figure, the inner wall portion 16 is inclined at an angle of inclination θ1 with respect to the axis of the cylinder 9.

Further, in the inner wall 15, an inner wall portion 17 on the opposite side to the inner wall portion 16 with respect to the position where the packing 13 is provided has an inclination angle θ2 with respect to the axis of the cylinder 9, and is formed to expand outward.

The inner wall 18 of the cylinder 10 is formed in a similar manner.

When pressure oil is supplied to the hydraulic chamber 11.12 during braking, the hydraulic piston 7.8 moves through the back metal 4, 5 to the friction pad 2,
3 is pressed against the disk plate 1.

At this time, if the friction pads 2 and 3 are unevenly worn, the hydraulic piston 7.8 receives a reaction force that is inclined with respect to the axes of the cylinders 9 and 10.

According to the present invention, the inner walls 15.18 of the cylinders 9, 10 are formed to have larger diameters as they move away from the packing 13.14 along the axis of the cylinders 9, 10, so that the hydraulic pistons 7.8 can be inclined within the cylinders 9,10.

This prevents the hydraulic piston 7.8 from biting into the cylinders 9, 10 and becoming integral with them.

The above-mentioned inclination angles θ1 and θ2 may be 45 minutes, for example, in a wheel brake used for a two-wheeled vehicle.

Note that these inclination angles θ1 and θ2 are as follows: (1) cylinder 9
, 10 can be determined from the amount of uneven wear of the friction pads 2, 3, which may become integral with the hydraulic pistons 7.8, and (2) the shape of the friction pads 2, 3.

As described above, according to the present invention, since the hydraulic piston can move at an angle within the cylinder, it is possible to prevent the hydraulic piston from biting into the inner wall of the cylinder, thereby causing dangerous situations such as so-called brake lock. is prevented and manufacturing becomes easier.

In particular, in the present invention, the hydraulic piston 7.8 has a right cylindrical shape,
Cylinder 9,1 housing this right cylindrical piston 7.8
The inner walls 15 and 18 of the cylinders 9 and 10 have larger diameters as they move away from both sides of the gaskets 13 and 14 (that is, left and right in FIG. 2) in the axial direction of the cylinders 9 and 10.
The work of forming the inner wall portions 16, 17 of the inner wall 15.18 of the hydraulic piston 7.8 by grinding or the like can be easily carried out, and the hydraulic piston 7.8 can be easily machined, thereby improving productivity.

Furthermore, in the present invention, since the piston 7.8 has a right cylindrical shape, even if the piston 7.8 protrudes from the cylinder 9.10, the sealing action is always ensured by the seal 13.14.

Therefore, an excellent effect is achieved in that there is no fear of pressure oil leaking from the hydraulic chambers 11, 12.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is an enlarged sectional view of section II of FIG. 1, FIG. 3 is a sectional view of a part of the prior art, and FIG. is a cross-sectional view of a portion of another prior art. 1... Teisuku plate, 2, 3... Friction pad, 4,
5... Back metal, 6... Support pin, 7, 8... Piston, 9°10... Cylinder, 11.12... Hydraulic chamber, 13.14... Packing, 15.18. ··inner wall,
16.17...Inner wall portion, θ1. θ2...Inclination angle.

Claims (1)

[Scope of utility model registration request] Cylinder 9,1 housing a right cylindrical hydraulic piston 7.8
A gasket 13.14 is provided on the piston 7.8 to form a fluid-tight hydraulic chamber 11.12 by slidingly contacting the outer peripheral surface of the piston 7.8. In a disc brake that obtains braking force by pressing against the inner walls 15, 1 of the cylinders 9, 10,
8 in the axial direction of the cylinders 9 and 10.
3.14 A disc brake characterized by a diameter that increases as it moves away from both sides.