JPH08121510A - Air bleeding structure of disk brake for hydraulic vehicle - Google Patents

Abstract

PURPOSE: To obtain good operating feeding by effectively discharging air which is mixed in operating liquid in a hydraulic system, and suppressing expansion of an operating stroke and sponge feeling, and also to improve freedom such as layout of a caliper shape, setting for a vehicle, operation of a brake hose, and improving general purpose property of a caliper body so as to use an air bleeding structure for a hydraulic vehicle in the other vehicle. CONSTITUTION: A circular cone or polygonal pyramid shaped funnel part 25b which is enlarged in a taper shape from a small diameter communicating hole 25 toward hydraulic chamber 22 is provided on the hydraulic chamber side of a bleeder hole 25, and opened at a wide area on the upper part of the hydraulic chamber 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic disc brake used in vehicles such as motorcycles and automobiles, and in particular, efficiently mixes air mixed with hydraulic fluid in a hydraulic system through a bleeder hole in a caliper body. It relates to a structure that allows discharge.

[0002]

2. Description of the Related Art In hydraulic disc brakes used for motorcycles and automobiles, if air is mixed in the hydraulic fluid in the hydraulic system, the operation stroke of the brake lever or brake pedal may be extended or the operation feeling may be reduced. Since a spongy state without fluffiness and rigidity may be created, a bleeder hole is provided in the caliper body to discharge the mixed air in the hydraulic fluid to the outside while filling the hydraulic system with hydraulic fluid. (For a disc brake having a bleeder hole, see, for example, Japanese Utility Model Publication No. 61-37873).

FIG. 4 shows a front fork 1 of a motorcycle.
The bleeder hole 3 described above is connected to the upper part of the hydraulic chamber 5 defined in the bottom part of the cylinder hole 4 by the bleeder boss part 2a protruding from the upper part of the caliper body 2. When the air is discharged, the bleeder screw 6 screwed to the outside of the bleeder hole 3 is loosened to allow the hydraulic fluid in the hydraulic chamber 5 to overflow from the bleeder hole 3, thereby discharging the air to the outside. I am trying to do it.

[0004]

In such a structure, when the caliper body 2 is attached to the front fork 1, the bleeder hole 3 is set so as to be located above the hydraulic chamber 5. Although the mixed air can be effectively discharged, since the bleeder hole 3 having a small circular hole communicates with the hydraulic chamber 5 having an inner peripheral surface having a large diameter, the air of the hydraulic fluid in the hydraulic chamber 5 can be discharged. It is difficult to collect the air, and it is often left as an air reservoir A in a part of the hydraulic chamber 5. For this reason, the angle of the bleeder hole 3 with respect to the hydraulic chamber 5 has been devised variously, but effective discharge can be performed in spite of restricting the shape design of the caliper body 2 and the setting on the front fork 1. could not.

Therefore, the present invention provides an air for a disc brake for a hydraulic vehicle in which the air mixed in the hydraulic fluid in the hydraulic system is effectively discharged and the degree of freedom in designing the shape of the caliper body and setting the vehicle body is increased. The purpose is to provide a punched structure.

[0006]

In order to achieve the above object, in the first invention, a bleeder hole for discharging mixed air in the working fluid is provided in a hydraulic chamber defined at the bottom of the cylinder hole of the caliper body. In the hydraulic vehicle disk brake provided in communication with each other, a funnel portion that expands in a taper shape toward the hydraulic chamber is formed in the bleeder hole.

In the second invention, the taper surface of the funnel portion is
Match the tangent line of the inner peripheral surface of the hydraulic chamber.

[0008]

According to the structure of the first aspect of the invention, the funnel portion of the bleeder hole opens over the hydraulic chamber over a wide area, and the area where the mixed air from the hydraulic fluid in the hydraulic chamber is taken into the bleeder hole is enlarged. To do. Further, in the second invention in which the taper surface of the funnel portion is aligned with the tangent line of the inner peripheral surface of the hydraulic chamber, the area in which the air in the hydraulic fluid is taken into the bleeder hole from the hydraulic chamber is further expanded,
Less air remains in the hydraulic chamber.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a front disc brake of a motorcycle will be described below with reference to FIGS. 1 and 2. The front disc brake 10 includes a disc rotor 12 pivotally supported at the lower end of a front fork 11 so as to be rotatable integrally with a front wheel (not shown) in the direction of arrow B, and a bracket 13 fixed to a disc turn-in side of the front fork 11. The caliper body 16 slidably supported in the disk axial direction via the two slide pins 14 and 15 and the operating portion 16a and the reaction portion 16b of the caliper body 16 face each other with the disk rotor 12 interposed therebetween. It is composed of a pair of friction pads 17 arranged.

The caliper body 16 includes the above-mentioned operating portion 16
a and a reaction portion 16b, and a bridge portion 16c that straddles the outer periphery of the disk rotor 12 and connects them. The action portion 16a is provided with cylinder holes 18 and 19, a union boss portion 16d and a bleeder boss portion 16e, and vehicle body mounting arms 16f and 16g, and a reaction force claw 16h is integrally formed with the reaction portion 16b.

The cylinder holes 18 and 19 are arranged side by side in the circumferential direction of the disk, and the body mounting arms 16f of the caliper body 16 are
16 g of the bracket 13 with slide pins 14 and 15
When it is supported by, the cylinder hole 19 on the disc feed-out side is arranged at a higher position than the cylinder hole 18 on the disc feed-in side. A piston 20 is inserted into each of the cylinder holes 18 and 19, and the piston 20 and the cylinder holes 18 and 19 are inserted.
The fluid pressure chambers 21 and 22 are defined between the fluid pressure chambers 21 and 22 and the bottom portion of the fluid passage 19, and the fluid pressure chambers 21 and 22 are communicated with each other through the fluid passage hole 23.

A union hole 24 is provided in the union boss portion 16d so as to communicate with the liquid passage hole 23, and a bleeder hole 25 is provided in the bleeder boss portion 16e so as to communicate with the upper portion of the hydraulic chamber 22 on the disc feeding side. Is provided. Bleeder hole 2
Reference numeral 5 denotes a large-diameter female screw hole 25a opening on the outer surface of the bleeder boss 16e and a funnel part 25b opening on the hydraulic chamber 22.
And a small diameter communication hole 25c that connects the female screw hole 25a and the funnel portion 25b in the middle, and when the caliper body 16 is mounted as described above, the caster of the front fork 11 has substantially the same angle. It is set on a slope.

A bleeder screw 26 is provided in the female screw hole 25a.
The bleeder hole 25 is normally screwed, and the bleeder hole 25 is normally blocked from communication with the outside by the bleeder screw 26. The union hole 24 is a reserve tank (not shown) which is connected to a separately provided well-known hydraulic master cylinder via a brake hose and is attached to the hydraulic master cylinder.
To the hydraulic chambers 21 and 22 of the caliper body 16 constitute a hydraulic system.

The hydraulic fluid pressurized by the hydraulic master cylinder is introduced into the union hole 24 through the brake hose by the rider's brake operation, and the hydraulic fluid hole 23 is further branched to both hydraulic chambers 21 and 22. Will be supplied. Each of the pistons 20 in the cylinder holes 18, 19 has a hydraulic chamber 21,
The hydraulic fluid supplied while enlarging 22 advances the cylinder holes 18 and 19 toward the opening, and presses the friction pad 17 on the working portion side to one side surface of the disk rotor 12. Next, the caliper body 16 moves to the action part side while being guided by the slide pins 14 and 15 by the above-mentioned reaction,
The reaction force claw 16h of the reaction portion 16b presses the friction pad 17 on the reaction portion side to the other side surface of the disc rotor 12, and a braking action is performed.

The funnel portion 25b of the bleeder hole 25 is formed in a conical shape or a polygonal pyramid shape that tapers from the small-diameter communication hole 25c toward the hydraulic chamber 22. The opening width of the funnel portion 25b is the funnel portion 2 when viewed in the radial direction of the cylinder hole 19.
Both taper surfaces of 5b spread inside the tangents C, C of the inner peripheral surface of the hydraulic chamber 22 toward the communication hole side edge of the funnel portion 25b (see FIG. 1), and in the axial direction of the cylinder hole 19. When viewed, one of the tapered surfaces of the funnel portion 25b has one hydraulic chamber 22.
Toward the outer peripheral edge of the bottom of the hydraulic chamber 2
2 toward the opening side of the cylinder hole 19 (Fig. 2
reference). Therefore, in the radial direction of the cylinder hole 19, the width is slightly narrower than the distance between the contact points between the inner circumferential surface of the hydraulic chamber 22 and the tangents C, C, but in the axial direction of the cylinder hole 19, the hydraulic chamber 22 is closed. The opening is larger than the depth. The above-mentioned funnel portion 25b is integrally formed with a dedicated core when the caliper body 16 is cast and molded, or is cut and formed by post-processing after casting and molding.

The present embodiment is configured as described above,
When the hydraulic system is filled with the hydraulic fluid, air mixed in the hydraulic fluid filled in the hydraulic system enters the inside of the caliper body 16 due to the feeding pressure of the hydraulic fluid and the above-described braking operation. Further, the hydraulic chamber 22 on the disk feeding side at the upper position
Go up.

A bleeder hole 2 communicating with the upper portion of the hydraulic chamber 22.
The hydraulic chamber side of 5 is a funnel portion 25b having a conical shape or a polygonal pyramid shape.
However, since it covers most of the upper portion of the hydraulic chamber 22 and spreads in a taper shape, the air rising in the hydraulic chamber 22 can be stored in the bleeder hole 25 in which the female screw hole 25a is closed by the bleeder screw 26. After being stored in the funnel portion 25b and the communication hole 25c, it is discharged to the outside from the screw hole 25a for loosening the bleeder screw 26.

Therefore, as compared with the conventional bleeder hole which does not have the funnel portion as in this embodiment on the hydraulic chamber side, the funnel portion 25b having a wide area is opened above the hydraulic chamber 22.
Since the air of the working fluid inside is effectively collected in the bleeder hole 25 and discharged to the outside, the operating stroke of the brake lever is extended due to the biting of the air, and a good operation feeling that suppresses the feeling of fluffy sponge is provided. Can be obtained.

Further, the air bleeding operation from the working fluid is carried out by a dealer with a well-equipped manufacturer and equipment while filling the working fluid with a pressure-feeding or evacuation device, and there is no such device. Although it was difficult for the dealer and the user side to bleed air, according to the present embodiment, by setting the funnel portion 25b, even small dealers and individual users can inject the hydraulic fluid from the reserve tank. The air in the hydraulic fluid can be discharged easily and efficiently.

Further, even if the bleeder hole 25 is slightly inclined from the setting, the funnel portion 25b which opens in a large area above the hydraulic chamber 22 compensates for this and the air mixed with the working fluid is effectively collected, so that the caliper The degree of freedom in designing the shape of the body 16, setting the front fork 11, setting the brake hose, and the like can be increased. In addition, since the setting angle of the bleeder hole 5 can be given a margin in this way, the caliper body 16 can be applied to other motorcycles having different casters of the front forks, and the versatility is expanded and the economy is increased. Can increase the physical effect.

FIG. 3 shows another embodiment of the present invention. When the funnel portion 25b is viewed in the radial direction of the cylinder hole 19, both tapered surfaces of the funnel portion 25b are connected to each other.
Tangents C, C of the inner peripheral surface of the hydraulic chamber 22 toward the side edge of the communication hole
To match the opening width of the funnel portion 25b with the two tangent lines C, C
This is different from the above-described embodiment in that it is widely secured to have the same size as the distance between the contacts.

In the present embodiment, the hydraulic chamber 22 on the disc feeding side is provided.
Most of the air that rises up can be collected and discharged by the funnel portion 25b, and a better operation feeling can be obtained. Further, the degree of freedom and versatility of the caliper body 16 are further expanded, so that the economic effect is great.

The present invention can be widely applied to hydraulic disc brakes having a hydraulic chamber at the bottom of the cylinder hole regardless of the type of caliper body and the number of cylinder holes. Further, the present invention can be applied to the disc brakes for the front wheels and the rear wheels of other bar handle vehicles and automobiles in addition to the motorcycles shown in the embodiments.

[0024]

According to the present invention, the air bleeder hole provided in communication with the hydraulic chamber is provided with a funnel portion that expands in a tapered shape toward the hydraulic chamber. The funnel that opens in a large area can effectively collect the air mixed in the hydraulic fluid in the hydraulic chamber and efficiently discharge it from the bleeder hole to the outside. It is possible to obtain a good operation feeling by suppressing the stroke extension and the fluffy sponge feeling. Further, since the air bleeding property is improved in this way, not only manufacturers and dealers who bleed air while filling the working fluid by using a device for pumping or vacuuming, but also a small device that does not have such a device. Even a dealer or an individual user can easily and efficiently discharge the air in the hydraulic fluid by injecting the hydraulic fluid from the reserve tank of the hydraulic master cylinder.

Further, even if the bleeder hole is slightly displaced from the regular set angle, the funnel portion which opens in a large area in the hydraulic pressure chamber compensates for this and the air in the hydraulic pressure chamber is effectively collected and discharged. Therefore, the degree of freedom in designing the shape of the caliper body, setting on the vehicle body, handling of the brake hose, etc. can be expanded. In addition, since the bleeder hole can have a wide range of setting angles in this way, it becomes possible to apply the caliper body to other vehicles that have different mounting angles to the vehicle body, thereby increasing versatility and economic effects. Can be increased.

Further, by aligning the taper surface of the funnel portion with the tangent line of the inner peripheral surface of the hydraulic chamber, the air in the hydraulic chamber can be discharged more effectively, so that a better operation feeling can be obtained. it can. In addition, the degree of freedom in designing the shape of the caliper body and the versatility for other vehicle types can be further expanded, so that the economic effect will be great.

[Brief description of drawings]

FIG. 1 is a partially sectional front view showing a state where a front disc brake according to an embodiment of the present invention is attached to a front fork of a motorcycle.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partially sectional front view showing a state in which a front disc brake according to another embodiment of the present invention is attached to a front fork of a motorcycle.

FIG. 4 is a partially sectional front view of a conventional front disc brake mounted on a front fork of a motorcycle.

[Explanation of symbols]

 10 ... Front disc brake 11 ... Motorcycle front fork 12 ... Disc rotor 14, 15 ... Slide pin 16 ... Caliper body 16a ... Working portion 16b ... Reaction portion 16d ... Union boss portion 16e ... Bleeder boss portion 16h ... Reaction force claw 17 ... Friction pad 18, 19 ... Cylinder hole 20 ... Piston 21, 22 ... Hydraulic chamber 23 ... Liquid passage hole communicating fluid chambers 21 and 22 ... Union hole 25 ... Bleeder hole 25a ... Female screw hole 25b ... Funnel portion 25c ... Communication hole 26 ... Bleeder screw A ... Air reservoir B ... Rotation direction of disk rotor 12 C ... tangential line of inner circumferential surface of hydraulic chamber 22

Claims (2)

[Claims] 1. A disc brake for a hydraulic vehicle, wherein a hydraulic chamber defined at the bottom of a cylinder hole of a caliper body is provided with a bleeder hole for discharging mixed air in the working fluid. An air bleeding structure for a disc brake for a hydraulic vehicle, characterized in that a funnel portion that expands in a taper shape toward the hydraulic chamber is provided. 2. The air bleeding structure for a hydraulic vehicle disc brake according to claim 1, wherein a taper surface of the funnel portion is aligned with a tangent line of an inner peripheral surface of the hydraulic chamber.