JP3359605B2 - Caliper for opposed piston type disc brake - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caliper for an opposed piston type disc brake, and more particularly to a caliper in which a pipe is cast inside the caliper and an internal oil passage is formed by the pipe to integrate the body parts.

[0002]

2. Description of the Related Art Each part of a caliper, that is, an inner part having an opposed cylinder, an outer part, and a bridge part straddling a disk are integrally formed, and a pipe is cast inside the caliper to form an internal oil passage with the pipe. The caliper of the opposing piston type disc brake is now open.
No. 5,009,045.

[0003] Since the entire body of the caliper is integrated, high rigidity, which is important in terms of braking performance, can be obtained. Further, since the internal oil passage is formed by a cast pipe, labor for manufacturing is omitted, and productivity can be improved, cost can be reduced, and weight can be reduced. However, the caliper of this type has a problem that prevents mass production. The problem is that the pipe set in the mold moves at the time of caliper casting, and the positional variation of the pipe becomes large. As a result, the defective rate is high and the pipe is not suitable for mass production.

FIG. 9 shows a pipe layout in a current caliper. FIG. 1 shows a caliper in which an inner portion 2, an outer portion 3, and a bridge portion 4 that straddles a disk are integrally formed, and a pipe 5 is cast therein. Cylinders 6 and 7 are formed in the inner part 2 and the outer part 3 so as to face each other, and the cylinders 6 and 7 communicate with each other by an oil passage formed by the pipe 5.

The cylinder 6 is connected to the outer cylinder 7.
In order to machine the cylinder from the inner side, a method is adopted in which the rear opening is closed by attaching an end plate (not shown) for liquid sealing after finishing the cylinder. In the illustrated caliper, both ends of the pipe 5 are extended to a ceiling portion and a lower portion in a posture in which the caliper is attached to a vehicle body at a cylinder bottom sealed by an end plate. The illustrated pipe 5 is initially connected at both ends via a part shown by a chain line in the figure, and is cut into two pipes as shown in FIG. In some cases, the pipe 5 is cast at a position overlapping with the bottom of the cylinder 7 and a part of the chain line portion is left without being cut off even after the cylinder processing.

Reference numeral 8 in the drawing denotes a bleeder mounting hole, in which a bleeder (not shown) for bleeding air is mounted. 9
Is a communication hole drilled from the bleeder mounting hole 8 toward the pipe 5, and when drilling this hole 9, a hole is drilled in the upper corner portion of the pipe 5 in the caliper mounting posture of the pipe 5 to connect the oil passage in the pipe. It communicates with the hole 9 to make it possible to release air when filling the brake oil.

[0007]

The caliper employing the pipe layout shown in FIG. 9 has a cylinder bore formed by adding a portion indicated by a chain line in the drawing of the pipe 5 and extra lengths at both ends of the pipe cut off at the time of finishing the cylinder 6. The caliper is set in a mold while being held by a molding core, and the caliper is cast in this state. Due to the thermal effects during this casting and the instability of the support, the pipe 5 moves in the mold and the pipe 5 moves. Position varies. Since the variation in the position is relatively large, it is not guaranteed that the communication hole 9 communicates with the pipe 5.

If the pipe 5 is not properly connected to the communication hole 9, air cannot be released when filling the brake oil. Also, even if the communication is performed, if the position is bad, the air cannot be completely removed, which adversely affects the braking performance.

As a measure for solving the problem, when the diameter of the pipe 5 and the diameter of the communication hole 9 are increased to a point where positional variations can be absorbed, the bleeder mounting hole 8 also increases, and the caliper size increases. The caliper may not fit in the specified space,
The machining allowance for processing such holes increases, which is not preferable in terms of productivity.

[0010] Because the problem has not been sufficiently solved, the caliper having the structure shown in FIG. 9 has not yet been put to practical use in mass-produced products despite its excellent characteristics.

It is an object of the present invention to devise a layout of an oil passage pipe to be cast therein so that air can be reliably vented.

[0012]

In order to solve the above-mentioned problems, according to the present invention, an inner portion having a cylinder opposed to a caliper, an outer portion, and a bridge portion straddling a disk are integrally formed. In an opposing piston type disc brake caliper in which an internal oil passage is formed with the pipe, one end of the pipe is directed to a bleeder mounting hole provided in an inner portion of the caliper or an air vent hole communicating with the bleeder mounting hole. It was.

It is preferable that the caliper is provided with a molding hole formed by a casting pin between one end of the pipe and the bleeder mounting hole, and the end of the pipe communicates with the bleeder mounting hole through the forming hole.

Further, the outer diameter of one end of the pipe is made smaller than the bleeder mounting hole, and the diameter difference between the outer diameter of one end of the pipe and the bleeder mounting hole is larger than the allowable radial displacement of the pipe end when the pipe is cast. Preferably, one end of the pipe is directly connected to the bleeder mounting hole. In this case, the end of the pipe may be reduced by drawing.

Further, one end of the pipe is branched into two branches, one of the branch pipes is communicated with a bleeder mounting hole by a cast-in pin, and the other is communicated with the ceiling of the inner cylinder in a posture in which the caliper is mounted on the vehicle body. Alternatively, a structure may be adopted.

With the above-described structure, the cast-in pin is attached to one end of the pipe facing the cast-in pin communicating with the bleeder mounting hole so as to close the opening of the pipe end, and the cast-in pin is used for forming a caliper. The caliper can be cast and fixed in this state after being positioned and fixed in the mold.

Instead of a pipe facing one of the forked pins that communicates with the bleeder mounting hole, one of the bifurcated pipes is provided with a mounting hole for the cast pin in the middle of the pipe. The caliper may be cast and fixed to the molding die.

Further, one end of the pipe facing the bleeder mounting hole is extended to a position protruding out of the caliper, and the extended portion of this pipe end is positioned and fixed in a caliper molding mold. In this state, the caliper is cast. After demolding, the excess length of the cast pipe can be removed by machining.

When casting is performed using a casting pin, a positioning surface for contacting the pipe end of the casting pin is provided, and the positioning of the pipe end in the axial direction of the casting pin at the time of caliper casting is performed on that surface. Can be adopted.

[0020]

When the one end of the cast pipe is directed to the cast-in pin which communicates with the bleeder mounting hole, the pipe end can be positioned and held by the method described above, thereby reducing the variation in the position generated at the time of casting. It is possible to reliably communicate the oil passage in the pipe with the bleeder mounting hole to perform reliable air release.

In the case where one end of the pipe and the bleeder mounting hole communicate with each other through a forming hole formed by a casting pin, the pipe end does not need to be cut at the time of finishing the bleeder mounting hole. When the oil passage pipe is cut, burrs are likely to occur. Therefore, it is desirable to avoid cutting as much as possible from the viewpoint of preventing foreign matter from entering the brake fluid. The requirement can be satisfied by interposing a molding hole formed by a casting pin.

Further, in a pipe in which the outer diameter of one end of the pipe is smaller than the bleeder mounting hole by a predetermined diameter difference and is directly connected to the bleeder mounting hole, the pipe end always fits inside the bleeder mounting hole. The problem of poor air bleeding, which can be considered when the connection is made while protruding from the bleeder mounting hole, and the problem of a stopper failure due to the bleeder after air bleeding does not occur. Further, in the case where the pipe end is reduced by drawing in this structure, the bleeder size does not need to be increased unnecessarily.

In addition, in the case where one branch pipe is made to reach the cylinder of the inner part with two ends of the pipe, it is not necessary to additionally work the air vent hole of the inner cylinder.

If a mounting hole for a cast-in pin is formed in the middle of the pipe instead of a pipe which branches to a forked pin to be branched and communicates with a bleeder mounting hole, an air vent hole for the inner cylinder is additionally manufactured. In addition, there is no need to branch the pipe into two branches.

[0025]

FIG. 1 shows a first embodiment of a caliper of the present invention. In the drawing, reference numeral 1 denotes a caliper integrally formed with an inner portion 2 having a cylinder 6, an outer portion 3 having a cylinder 7, and a bridge portion 4 straddling a disk (not shown). A pipe 5 is cast into the caliper 1, and the pipe 5 forms an oil passage in the caliper 1 that connects the cylinders 6 and 7. The rear opening of the cylinder 6 is sealed in a liquid-tight manner by an end plate (not shown).
A brake fluid inlet (not shown) is provided in the end plate or in a caliper near the end plate, and after the pistons (not shown) for the cylinders 6 and 7 are assembled, brake oil is supplied to the cylinder 6 from the inlet. be introduced.

As shown in FIG. 2, a casting pin 10 is attached to one end of the pipe 5, and the casting pin 10 is positioned and held by a caliper mold 11 (only a part of which is shown in the figure). An extra length portion 5a is provided at the other end, and the extra length portion and the entry portion 5b into the cylinder 7 are held by a core 12 for forming a pilot hole in the cylinder. Casting.

After demolding, the cylinder 6 shown in FIG.
7 at this time, the extra length 5a and the cylinder 7
The cut-in portion 5b is cut off. Also, the casting pin 10
The bleeder mounting hole 8 is formed by finishing the hole formed by the above method. At this time, a molding hole (1 in FIG. 1) is formed between the bleeder mounting hole 8 and one end of the pipe 5 by a casting pin.
When 3) is left, one end of the pipe 5 does not need to be cut, and the occurrence of burrs can be reduced.

In FIG. 1, reference numeral 14 denotes a cylinder bleeder mounting hole 8 when the cylinder 6 is mounted on the vehicle body with the caliper mounted thereon.
Air vent hole that communicates with This hole 14 is drilled and one end is sealed with a plug 15. The positional deviation of the pilot hole of the bleeder mounting hole 8 is suppressed to be small by the positioning of the cast-in pin 10. Therefore, when the hole 14 is opened at the design position, the hole 14 reliably communicates with the bleeder mounting hole 8.

In FIG. 1, even if the position of the bleeder mounting hole 8 is changed to the bleeder mounting hole 8 and the position of the bleeder mounting hole 8 is changed to the air bleeding hole 14, the bleeder mounting hole and the pipe 5 can be reliably communicated. Can be.

The casting pin 10 is provided with a stepped surface 10 shown in FIG.
When a is provided, the end of the pipe 5 is received on the surface 10a, and the pipe 5 can be positioned in the axial direction of the casting pin. In addition, by inserting the pouring pin 10 into the pipe 5, the end of the pipe 5 is made to coincide with the radial direction of the pouring pin, and it is possible to more reliably position the axial direction and the radial direction of the pouring pin. .

FIG. 4 shows a second embodiment. The caliper extends one end of the pipe 5 in the axial direction of the bleeder mounting hole 8 to a position where the caliper projects outside.
Hold the position with 1. The outer diameter of one end of the pipe 5 is smaller than that of the bleeder attachment hole 8, and the difference in diameter from the hole 8 absorbs the displacement of the pipe end in the radial direction when the pipe is cast. The extension 5c is cut off when the bleeder mounting hole 8 is processed. The other parts are the same as the calipers of FIG.

In the caliper shown in FIG. 4, since the outer diameter of the pipe 5 is made equal in the entire area, the diameter of the bleeder mounting hole 8 is inevitably increased. However, as shown in FIG. When the diameter is reduced and reduced to a point where a diameter difference larger than the allowable value of the displacement between the mounting hole 8 and the mounting hole 8 is formed, it is possible to avoid an increase in the diameter of the bleeder mounting hole (that is, an increase in the size of the bleeder). .

FIG. 6A shows a connection state between the pipe end and the bleeder mounting hole in the structure for processing the pipe end face shown in FIGS. 4 and 5, wherein one end of the pipe 5 is accommodated inside the bleeder mounting hole 8. I have. As shown in FIG. 6B, if one end of the pipe 5 protrudes from the bleeder mounting hole 8, the bleeder may cause a stopper failure or insufficient air release.
The outer diameter of one end of the pipe 5 is made small, and it becomes easy to absorb the radial displacement of the end of the pipe due to the difference in diameter from the bleeder mounting hole. In particular, the axial direction of the pipe at one end of the pipe and the axial direction of the bleeder mounting hole are made parallel, and the positional deviation of the axis is set to a range in which the outer diameter of the pipe is contained within the bleeder mounting hole. Function is secured.

FIG. 7 shows a state in which one end of the pipe 5 is forked and one branch pipe 5d is directed toward the bleeder mounting hole 8, and the other branch pipe 5e is moved to the cylinder ceiling portion in the posture in which the caliper of the cylinder 6 is mounted. 9 shows a main part of a caliper according to a third embodiment. Here, the casting pin 10 is inserted into the branch pipe 5d and is positioned and held. However, as described with reference to FIGS. 4 and 5, the extension of the branch pipe end can be positioned and held by the mold. .

When the positioning is performed by the casting pin 10, as shown in FIG. 8A, the pipe 5 is bent in the middle to form a hole 16 in the bent portion, and the casting pin 1 is inserted into the hole 16.
0 can be attached for positioning. Further, FIG.
As shown in (b), if the casting pin 10 is inserted into the hole of the pipe 5, the orientation and position of the pipe 5 can be more reliably maintained. The hole 16 may be considered to have a minimum length of the branch pipe 5d in FIG. 7, and this structure also has an advantage of a structure in which the pipe ends are forked (additional processing of the air vent hole of the inner cylinder is not necessary. Unnecessary).

The present invention can be applied to a caliper having two or more cylinders in the inner portion and the outer portion.

[0037]

As described above, in the caliper of the present invention, one end of the cast pipe forming the internal oil passage is directed to the bleeder mounting hole, so that the cast pin is attached to the end of the pipe. Positioning can be performed by
In addition, the pipe end can be extended in the axial direction of the bleeder mounting hole to perform positioning by the extension, which allows reliable air bleeding without increasing the diameter of the bleeder mounting hole and thereby increasing the size of the bleeder. Thus, an integrated caliper having no practical problem can be realized.

In the case where the pipe end and the bleeder mounting hole are communicated with each other through a forming hole formed by a cast-in pin, the pipe end is not cut, so that burrs due to cutting are prevented, and foreign matter is prevented from entering the brake oil. The effect also increases.

In the case where the outer diameter of the pipe end is made smaller than the bleeder mounting hole so as to absorb the radial displacement of the pipe end due to the difference in diameter, the bleeder is moved even when the pipe end moves during casting. Poor connection with the mounting hole does not occur.

In addition, when the pipe has two ends, the air vent hole of the inner cylinder is formed by one branch pipe, and the drilling and plugging of the hole can be omitted.

In place of a pipe which branches to a forked pin which branches into a bleeder mounting hole and communicates with the bleeder mounting hole, an air vent hole for the inner cylinder is additionally formed by forming a mounting hole for the cast pin in the middle of the pipe. This eliminates the need for branching the pipe into two branches.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of a caliper of the present invention.

FIG. 2 is a view showing a positioning and holding state of a pipe cast into the caliper of FIG. 1;

FIG. 3 is a plan view of a casting pin having a step surface for axial positioning.

FIG. 4 is a plan view of a caliper according to a second embodiment.

FIG. 5 is a plan view of a caliper cast by drawing a pipe end.

6 (a) is an end view showing a connection state between a pipe and a bleeder mounting hole in the caliper shown in FIGS. 4 and 5;

FIG. 7 is a sectional view showing a main part of a caliper according to a third embodiment.

8A is a cross-sectional view showing a main part of a caliper in which one side of a branch pipe of the caliper in FIG. 7 is replaced with a hole. FIG. 8B is a cross-sectional view showing an example in which a casting pin is inserted into a hole of the pipe.

FIG. 9 is a plan view of a caliper employing a current pipe layout.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Caliper 2 Inner part 3 Outer part 4 Bridge part 5 Pipe 5a Extra length 5b Entrance part 5c Extension part 5d, 5e Branch pipe 6, 7 Cylinder 8 Bleeder attachment hole 9 Communication hole 10 Cast-in pin 10a Step surface 11 Mold 12 Medium Child 13 Molding hole 14 Air vent hole 15 Plug 16 Hole to substitute for branch pipe

──────────────────────────────────────────────────続 き Continuing on the front page (72) Kaoru Sugita, 2-2-20 Higashishinagawa, Shinagawa-ku, Tokyo Nihon Light Metal Co., Ltd. (72) Yoshihiro Tajima 1-34 Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture No. 1 Nippon Light Metal Co., Ltd. Group Technology Center (72) Inventor Masayuki Yasuda 43-3 Harumicho, Tomakomai City, Hokkaido Nippon Light Metal Co., Ltd. Tomakomai Plant (72) Inventor Tetsuo Ishikawa 43-3 Harumicho, Tomakomai City, Hokkaido No. Nippon Light Metal Co., Ltd. Tomakomai Works (56) References JP-A-6-74266 (JP, A) JP-A-11-342460 (JP, A) JP-A-2000-97262 (JP, A) JP-A-11 -108088 (JP, A) JP-A-9-177843 (JP, A) JP-A-10-30660 (JP, A) JP-A-56-5833 (JP, U) JP-B-42-6946 (JP, B1) ) (58 ) Field surveyed (Int.Cl. ⁷ , DB name) F16D 55/22-55/228 F16D 65/00-65/02

Claims (8)

(57) [Claims] An opposed piston having a caliper, an inner portion having an opposed cylinder, an outer portion, and a bridge portion straddling a disk, integrally formed, a pipe cast into the interior of the caliper, and an internal oil passage formed by the pipe. A caliper for an opposed piston type disc brake, wherein one end of the pipe is directed to a bleeder mounting hole provided in an inner portion of the caliper or an air vent hole communicating with the bleeder mounting hole. 2. The opposed piston according to claim 1, wherein a molding hole made of a casting pin is provided between one end of the pipe and the bleeder mounting hole, and the pipe end communicates with the bleeder mounting hole via the molding hole. Caliper for type disc brake. 3. An outer diameter of one end of the pipe is made smaller than a bleeder mounting hole, and a diameter difference between the one end outer diameter of the pipe and the bleeder mounting hole is larger than a permissible radial displacement of the pipe end at the time of casting the pipe. 2. A caliper for an opposed piston type disc brake according to claim 1, wherein said caliper is made larger and one end of said pipe is directly connected to said bleeder mounting hole. 4. A caliper for an opposed-piston disc brake according to claim 3, wherein one end of the pipe is drawn so that an outer diameter of the one end is smaller than a bleeder mounting hole. 5. The pipe according to claim 1, wherein one end of the pipe is branched into two branches, one of the branch pipes is communicated with a bleeder mounting hole, and the other is communicated with a ceiling portion of the inner cylinder in a posture in which a caliper is mounted on a vehicle body. Item 2. A caliper for an opposed piston type disc brake according to Item 1. 6. A method for manufacturing a caliper according to claim 1, wherein a cast-in pin for forming a pilot hole of the bleeder mounting hole at one end of the pipe facing the bleeder mounting hole is in a state of closing the opening of the pipe end. A method of manufacturing a caliper for an opposed-piston disc brake, comprising: mounting, positioning and fixing the unmolded pin in a caliper molding mold, and casting the caliper in this state. 7. The opposed piston according to claim 6, wherein a positioning surface for abutting the pipe end is provided on the pouring pin, and the caliper casting is used to position the pipe end in the axial direction of the pouring pin when the caliper is cast. Of manufacturing caliper for die-type disc brake. 8. The method for manufacturing a caliper according to claim 1, wherein one end of the pipe facing the bleeder mounting hole is extended to a position protruding outside the caliper, and the extended portion of the pipe end is used as a mold for caliper molding. A method of manufacturing a caliper for an opposed-piston type disc brake, wherein the caliper is cast in this state, and after removing the mold, the excess length of the cast pipe is removed by machining.