JPH08159191A - Caliper body for disc brakes for hydraulic vehicles - Google Patents

Abstract

(57) [Summary] [Purpose] Prevent the friction pad lining from being unevenly worn due to the C-shaped deformation of the caliper body due to the braking reaction force, tilting of the caliper body due to bending moment, and the leading action of the friction pad. To [Structure] A piston 20 is inserted into a cylinder hole 18 through a piston seal 24. Inside the piston 20, a small-diameter inner cylinder hole 21 opening toward the disc rotor side
Is provided on the inner circumference side of the disc with respect to the central axis O1 of the piston 20 by a distance of L1. The inner piston 22 is inserted into the inner cylinder hole 21 via the inner piston seal 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caliper body of a hydraulic disc brake used in various traveling vehicles such as automobiles and motorcycles, and more specifically, to prevent uneven wear of a friction pad lining as much as possible. Regarding the structure of the caliper body.

[0002]

2. Description of the Related Art As a caliper body for a hydraulic vehicle disc brake used in an automobile or the like, for example
-1704 and JP-A-4-87037. In the former caliper body, a piston is inserted into the cylinder hole of the action part to define a hydraulic chamber between the piston and the bottom part of the cylinder hole, and an auxiliary piston is provided between the fitting part of the cylinder hole and the piston. The first piston seal is interposed between the auxiliary piston and the cylinder hole, and the second piston seal is interposed between the fitting portion between the auxiliary piston and the piston. Seals the hydraulic chamber in a liquid-tight manner by pressing the auxiliary piston toward the disc rotor with a biasing force larger than the sliding resistance of the first piston seal between the auxiliary piston and the cylinder hole. When the braking is released, the urging means is provided and the sliding resistance of the second piston seal is set to be larger than the sum of the sliding resistance of the urging means and the first piston seal. Piston, thereby pushed deep into the bottom of the cylinder bore beyond the retracted position set by the excessive restoring force, so as to prevent the occurrence of so-called knock back.

Further, in the latter caliper body, the outer diameter and the inner diameter of the tip end surface of the piston inserted in the cylinder hole of the acting portion are eccentric in the disk radial direction and the disk circumferential direction, and the thickness of the piston tip end surface is made non-uniform. By forming concentric circles,
The pressing surface at the tip of the piston with respect to the friction pad is deviated to prevent the peripheral speed difference between the inner and outer circumferences of the disc rotor, the C-shaped deformation of the caliper body, and the uneven wear of the lining of the friction pad due to the leading action.

FIG. 9 is a partially enlarged view showing a general mounting state of a piston used in a caliper body of a hydraulic vehicle disc brake, including the above-mentioned two conventional examples.
The piston 1 is formed to have a smaller diameter than the cylinder hole 3 of the caliper body 2 and a smaller diameter than the inner peripheral surface of the piston seal 4 fitted in the seal groove 3 a of the cylinder hole 3. It is supported by the piston seal 4 with a small clearance between them while it is being tightened. During operation, the piston seal 4 is deformed on the inner peripheral side and advances toward the disc rotor, and when braking is released by the restoring force of the piston seal 4. It is designed to return to the retracted position.

[0005]

However, the former caliper body described above does not take special measures against uneven wear against the friction pad, and the lining of the friction pad due to deformation of the caliper body, leading action, or the like. Uneven wear was inevitable.

Further, in the latter caliper body for the purpose of preventing uneven wear of the friction pad, the bending deformation of the piston seal is utilized, and the inclination of the piston due to the deformation or tilting of the caliper body is allowed by the bending of the piston seal. By doing so, the piston is made to face the friction pad as much as possible to prevent uneven wear, but there is a limit to the amount of bending of the piston seal, and it may not be possible to take sufficient measures.

[0007] For example, low fuel consumption due to weight reduction of the vehicle body is a social demand to reduce exhaust gas and noise to secure a living environment and protect a natural environment. It is effective to make the caliper body thinner and more compact while ensuring the rigidity required for a large caliper body, but in this case, the deformation and behavior of the caliper body will be even greater, so the latter With this structure, it was difficult to make the piston face the friction pad.

Therefore, the present invention is a hydraulic type that can effectively suppress uneven wear of the lining of the friction pad even if the caliper body deforms or behaves during braking or the friction pad causes a leading action. The purpose is to provide a caliper body for a vehicle disc brake.

[0009]

In order to achieve the above object, in the first aspect of the invention, a cylinder hole is provided in the action portion arranged on the side portion of the disc rotor so as to open toward the disc rotor side. A piston is inserted into the hole to define a hydraulic chamber between the piston and the bottom of the cylinder hole, and the working fluid supplied to the hydraulic chamber advances the piston toward the disc rotor to cause friction. In a caliper body of a vehicle disc brake that pushes a pad to bring a lining of the friction pad into sliding contact with a side surface of the disc rotor, an inside of the piston that opens toward the disc rotor side in a caliper body of a vehicle disc brake. A cylinder hole is provided offset from the center axis of the piston to the disk inner peripheral side, and the inner piston is inserted into the inner cylinder hole, and between the inner piston and the bottom wall of the piston. An inner piston seal that defines a side hydraulic chamber, movably supports the inner piston, and seals the inner hydraulic chamber between the fitting portions of the inner piston and the piston is interposed. A piston seal that movably supports the piston and seals the hydraulic chamber liquid-tightly is provided between the fitting portion of the piston and the cylinder hole, and liquid is allowed to pass through the bottom wall of the piston. A hole is bored to communicate the hydraulic chamber with the inner hydraulic chamber.

According to the second aspect of the present invention, the action portion disposed on one side portion of the disc rotor, the reaction portion disposed on the other side portion of the disc rotor, and the bridge portion connecting these to each other across the outer periphery of the disc rotor. And a piston is inserted into a cylinder hole provided on the action portion so as to open toward the disc rotor side to define a hydraulic chamber between the piston and the bottom of the cylinder hole. With the supplied hydraulic fluid, the piston is advanced in the direction of the disc rotor to push the friction pad, and the lining of the friction pad is brought into sliding contact with the side surface of the disc rotor to perform a braking action on the vehicle disc brake. In the caliper body, the inside cylinder hole that opens toward the disc rotor is provided in the inside of the piston so as to be offset from the center axis of the piston toward the disc payout side. The inner piston is inserted into the inner piston to define an inner hydraulic chamber between the inner piston and the bottom wall of the piston, and the inner piston is movable between the fitting portion of the inner piston and the piston. An inner piston seal that supports and seals the inner hydraulic chamber in a liquid-tight manner is interposed,
A piston seal that movably supports the piston and seals the hydraulic chamber in a liquid-tight manner is interposed between the fitting portion of the piston and the cylinder hole, and a liquid passage hole is formed in the bottom wall of the piston. The hydraulic chamber and the inner hydraulic chamber are communicated with each other by drilling.

According to the third aspect of the present invention, cylinder holes that open toward the disk rotor are provided facing each other on both action portions provided on both sides of the disk rotor, and pistons are inserted into the cylinder holes to form pistons. And a bottom of the cylinder hole to define a hydraulic chamber, and the working fluid supplied to the hydraulic chamber advances the piston in the direction of the disk rotor, so that the lining of the friction pad is directed to the side surface of the disk rotor. In the caliper body of the vehicle disc brake that presses,
Inside the piston, an inner cylinder hole that opens toward the disc rotor is provided so as to be offset from the center axis of the piston toward the disc feed-out side, and the inner piston is inserted into the inner cylinder hole to form the inner piston. An inner hydraulic chamber is defined between the inner wall of the piston and the bottom wall of the piston, the inner piston is movably supported between the fitting portion of the inner piston and the piston, and the inner hydraulic chamber is liquid-tight. An inner piston seal that seals between the piston and the cylinder hole, and a piston seal that movably supports the piston and that seals the hydraulic chamber in a liquid-tight manner. A fluid passage hole is bored in the bottom wall of the piston to communicate the fluid pressure chamber with the inner fluid pressure chamber.

[0012]

In the structure of the first aspect of the present invention, when the caliper body is opened and deformed in a V shape with the bridge portion as the fulcrum by the braking reaction force from the friction pad, the opening amount from the friction pad is small. On the outer peripheral side of the disc, the outer piston pushes the friction pad while bending the piston seal,
On the inner side of the disc, which is far away from the friction pad,
The inner piston protrudes from the tip end surface of the outer piston while bending the inner piston seal, and pushes the friction pad.

FIG. 3 is a partially enlarged cross-sectional view of the caliper body used in the first embodiment of the present invention, showing the details of the operation of the piston and the inner piston when the caliper body is deformed in a V shape. By the braking reaction force from the friction pad 15,
Working portion 14a of the caliper body 14 that deforms as shown
On the other hand, on the outer peripheral side of the disc, the piston 20 is bent while the piston seal 24 is bent so as to correct the deformation of the action portion 14a and face the friction pad 15 as much as possible.
The inner surface of the friction pad 15 is slightly inclined and advances toward the disk rotor, and the tip end surface 20a pushes the rear surface of the back plate 17 of the friction pad 15.
Further, on the inner peripheral side of the disk, the inner piston 22 in the inner cylinder hole 21 tilts integrally with the outer piston 20, and the inner piston 22 is further deformed by the working fluid supplied to the inner hydraulic chamber 27. In order to correct and correct the friction pad 15 as much as possible, while bending the inner piston seal 26, the inner cylinder hole 21 is slightly inclined and moved forward, and the front end surface 22a presses the rear surface of the back plate 17.

As described above, the inclination of the inner piston 22 with respect to the deformation of the acting portion 14a is allowed to be larger than that of the outer piston 20 due to the bending deformation of both the piston seal 24 and the inner piston seal 26, and the opening amount is large. The inner piston 2 is located on the inner circumference side of the disc of the portion 14a.
2 can be pushed toward the friction pad 15 as close as possible to the front face.

In the structure of the second aspect of the present invention, the drag torque from the friction pad acts as a bending moment on the caliper body during braking, so that the disc entry side of the acting portion and the disc exit side of the reaction portion act as the disc. When the caliper body tilts so as to approach the rotor and the disc spill-out side of the action part and the disc spill-in side of the reaction part move away from the disc rotor, the outer piston seals the outer piston seal on the disc slew-in side. The friction pad is pushed while bending, and the inner piston pushes the friction pad while projecting from the tip end surface of the outer piston while bending the inner piston seal on the disc feeding side.

Inclination of the inner piston due to the outer piston seal and the inner piston seal is also allowed in the configuration of the second invention, and the inner piston is on the disc squeeze side of the action portion which tends to separate from the friction pad. In order to correct the deformation of the acting portion, the friction pad can be tilted so as to face the friction pad as much as possible, and the tip end surface of the friction pad can be brought into contact with the friction pad as closely as possible.

Further, in the structure of the third aspect of the invention, the friction pad during braking is dragged in the disc payout direction by the drag torque generated by the sliding contact with the disc rotor, and the disc turn-in side of the friction pad becomes free. When a so-called leading action occurs in which the disc is wound around the disc rotor, the inner piston, which is offset from the center axis of the piston toward the disc squeeze side, projects from the tip surface of the outer piston and disc of the friction pad. Push the sending side independently.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show the first embodiment and FIG.
Is the second embodiment, FIG. 5 is the third embodiment, and FIGS. 6 and 7 are the fourth embodiment.
Example, FIG. 8 shows a fifth example, respectively. Of the drawings of these embodiments, except FIG. 3 of the first embodiment, the gap between the piston and the cylinder hole, the gap between the inner piston and the inner cylinder hole, and the deformation of the piston seal and the inner piston seal during braking are shown. Was omitted. Further, the same reference numerals are given to the components common to the respective embodiments, and detailed description thereof will be omitted.

The disk brake 10 of the first embodiment shown in FIGS. 1 to 3 is a disk rotor 11 which rotates integrally with a wheel (not shown) in the direction of arrow A, and is fixed to the vehicle body at one side of the disk rotor 11. Caliper bracket 12 and
The caliper bracket 12 has a pair of slide pins 13,
And a pair of friction pads 15 and 15 that are disposed to face each other with the disc rotor 11 sandwiched between the working portion 14a and the reaction portion 14b of the caliper body 14. There is.

The caliper bracket 12 has a bridge portion 14 of the caliper body 14 on the outer periphery of the disc rotor 11.
The caliper support arms 12a, 12a protruding in the disc axial direction while sandwiching c are provided, and the caliper support arms 12a, 12a have stepped pad receiving surfaces 12b, 12a.
b are provided facing each other.

The caliper body 14 is the disk rotor 1.
The above-mentioned action portion 14a and reaction portion 14b are arranged to face each other on one side, and a bridge portion 14c that straddles the outer circumference of the disk rotor 11 and connects them. The action portion 14a has a cylinder hole 1 that opens toward the disc rotor.
8, a union hole 19 penetrating the bottom wall 14d of the cylinder hole 18 in and out, a pair of slide pin mounting arms 14e and 14e projecting from the disk entry side and the ejection side, and the reaction portion 14b. Is provided with a reaction force claw 14f.

The slide pin mounting arms 14e, 14e are provided with the above-mentioned slide pins 13, 13 so that the caliper body 14 has both slide pins 13, 13 in the pin holes 12c, 12c of the caliper support arms 12a, 12a. And is supported so as to be movable in the disc axial direction.

The friction pad 15 is constructed by joining a lining 16 which is in sliding contact with the side surface of the disk rotor 11 to a metal back plate 17, and has ear pieces 17a and 17a protruding above both side parts of the back plate 17, respectively. Caliper support arms 12a, 1
It is hooked on the pad receiving surfaces 12b and 12b of 2a, and is movably suspended in the disc axial direction. Lining 16
And the outer peripheral side of the central disk of the back plate 17 is recessed and fitted, enhancing the joining force between the lining 16 and the back plate 17, and processing the binding concave hole of the back plate 17 with half piercing,
A projection 17b having a quadrangular cross section is projected on the back surface of the back plate 17.

A cylindrical piston 20 having a bottom is inserted into the cylinder hole 18 with its front end surface 20a facing the disk rotor side, and an inner cylinder hole 21 of the piston 20 is further inserted.
Also, a cylindrical inner piston 22 with a bottom is also attached to the tip surface 2
2a is inserted with the disc rotor facing toward the disc rotor side. Of these, the cylinder hole 18 and the piston 20 have the same basic structure as the conventional one, and a small diameter inner cylinder hole 21 and an inner piston 22 are newly added to this basic structure. The central axis O2 of the inner cylinder hole 21 is provided so as to be deviated from the central axis O1 of the piston 20 toward the inner circumferential side of the disc by a length L1.
There is a notch 20c on the outer peripheral side of the disk of a, and the protrusion 17b of the friction pad 15 on the action portion side is provided in this notch 20c.
Are engaged to form a rotation stopping means 23 for the piston 20.

A piston seal 24 is interposed between the fitting portion of the cylinder hole 18 and the piston 20. The piston seal 24 movably supports the piston 20 in the cylinder hole 18, and Hole 18 and piston 2
A hydraulic chamber 25 defined between both bottom walls 14d and 20b of 0 is liquid-tightly sealed. Further, between the fitting portion of the inner cylinder hole 21 and the inner piston 22, the inner piston seal 2
6, the inner piston 22 is movably supported in the inner cylinder hole 21 by the inner piston seal 26, and the piston 20 and the inner piston 22 are
Inner hydraulic chamber 27 defined between both bottom walls 20b, 22b of the
Are sealed liquid-tight by the inner piston seal 26.

A liquid passage hole 20 is formed in the bottom wall 20b of the piston 20.
d is formed through, and the hydraulic chamber 25 and the inner hydraulic chamber 27 are
The hydraulic fluid, which is communicated through the fluid passage hole 20d and is pressurized by a separately-provided publicly known hydraulic master cylinder (not shown), enters the fluid pressure chamber 25 through the union hole 19 and further passes through the fluid passage hole. It is adapted to be supplied to the inner hydraulic chamber 27 through 20d.

The hydraulic fluid supplied to the hydraulic chamber 25 advances the piston 20 toward the disc rotor, and the hydraulic fluid supplied to the inner hydraulic chamber 27 advances the inner piston 22 toward the disc rotor. , Each tip surface 20
a, 22a pushes the friction pad 15 on the action portion side to move the lining 16 of the friction pad 15 to the disc rotor 11
Slide to one side.

Next, the caliper body 14 moves toward the acting portion while being guided by the slide pins 13, 13 by the above-mentioned reaction, and the reaction force claw 14f of the reaction portion 14b pushes the friction pad 15 on the reaction portion side. Then, the lining 16 of the friction pad 15 is brought into sliding contact with the other side surface of the disc rotor 11 to perform a braking action.

In the above braking action, the friction pads 15, 1
The braking reaction force from 5 causes the piston 20 and the inner piston 2 to
2, through the reaction force claw 14f, the action portion 14a and the reaction portion 1
4b and the caliper body 14
Deforms in a V shape with the bridge portion 14c as a fulcrum, but the opening amount from the friction pad 15 is small.
On the outer peripheral side of the disk, the piston 20 is
In order to correct the deformation of the piston pad 24 and to face the friction pad 15 as much as possible, the piston seal 24 is bent, and the inside of the cylinder hole 18 is slightly inclined and advanced toward the disk rotor to move the tip surface 20a.
Pushes the back surface of the back plate 17 of the friction pad 15.

On the inner peripheral side of the disk, the inner piston 22 in the inner cylinder hole 21 is tilted integrally with the outer piston 20, and the inner piston 22 is further actuated by the working fluid supplied to the inner hydraulic chamber 27. In order to correct the deformation of 14a and to face the friction pad 15 as much as possible, the inner cylinder seal 21 is bent and the inner cylinder hole 21 is slightly inclined and moved forward, and the front end surface 22a presses the back surface of the back plate 17.

As described above, the piston 20 pushes the outer peripheral side of the disk of the working portion 14a, and the inner peripheral side of the disk of the working portion 14a having a large opening amount is connected to the central axis O2 of the piston 20.
Then, the inner piston 22 offset by the length L toward the inner circumference of the disc obtains the amount of deflection of the piston seal 24 and the inner piston seal 26, and pushes while facing the friction pad 15 as much as possible. Therefore, even if the C-shaped deformation of the caliper body 14 occurs due to the braking reaction force, the piston 20 and the inner piston 22 can effectively suppress the uneven wear of the lining 16 of the action portion side friction pad 15, and Even if the caliper body 14 is made thinner and smaller in order to reduce the weight of the vehicle body and the C-shaped deformation is increased, the uneven wear of the lining 16 of the action side friction pad 15 is correspondingly minimized. You will be able to suppress.

Further, in this embodiment, a lightweight and heat-resistant synthetic resin is used for the piston 20 having a large mass, and the small-diameter inner piston 22 is also made of the same synthetic resin to further reduce the weight. Is desirable.

Next, a second embodiment of the present invention will be described with reference to FIG. The caliper body 31 used for the disc brake 30 has a pair of operating portions 31 a, 31 b, which are separately arranged on both sides of the disc rotor 11, in which cylinder holes 32, 32 opening toward the disc rotor are formed so as to face each other. A pair of friction pads 33, 33, which is a piston facing type in which a bottomed cylindrical piston 37 is inserted, is hung on both sides of the disc rotor 11 by a hanger pin 36 above the back plate 35. 34 is disposed so as to face the disc rotor side.

In each cylinder hole 32, the above-mentioned piston 3 is provided.
7, the tip end surface 37a on the opening side is inserted into the disk rotor side, and a hydraulic chamber 38 is defined between the cylinder hole 32 and both bottom walls 31c and 37b of the piston 37. The piston 26 is provided with a small-diameter inner cylinder hole 39 that opens toward the disc rotor, with its central axis O4 offset from the central axis O3 of the piston 26 toward the inner circumferential side of the disc by a length L2. A bottomed cylindrical inner piston 40 is also inserted in the inner cylinder hole 39 with the tip end surface 40a on the opening side facing the disc rotor side.
7 between the bottom walls 37b and 40b of the inner piston 40,
An inner hydraulic chamber 41 is defined.

A piston seal 42 is interposed between the fitting portion between the cylinder hole 32 and the piston 37, and the piston seal 42 movably supports the piston 37 in the cylinder hole 32, and The pressure chamber 38 is liquid-tightly sealed. Also, the inner cylinder hole 39 and the inner piston 40
An inner piston seal 43 is interposed between the fitting portions of the inner piston 40 and the inner piston seal 43.
Is movably supported in the inner cylinder hole 39, and the inner hydraulic chamber 41 is liquid-tightly sealed.

A liquid passage hole 37 is formed in the bottom wall 37b of the piston 37.
c is provided so as to penetrate therethrough, and the hydraulic chambers 38 and the inner hydraulic chambers 41 of the respective action portions 31a and 31b are respectively provided with the liquid passage holes 37.
The hydraulic fluid, which is communicated via c and is pressurized by the hydraulic master cylinder, is supplied to both hydraulic chambers 38, 38 through a liquid passage hole (not shown) continuously provided for the working portions 31a, 31b. The liquid is supplied to each inner hydraulic chamber 41 through the liquid passage hole 37c of the piston 37.

An engaging hole 37d is opened to the disk rotor side on the disk outer peripheral side of the piston 37, and a projection 35a protruding to the back surface of the back plate 35 of the friction pad 33 is engaged with the engaging hole 37d. And the rotation stopping means 44,
By restricting the rotation of the piston 37 by the rotation stopping means 44, the inner piston 40 is held closer to the disk inner peripheral side than the central axis O3, and the C-shaped character of the caliper 31 is provided as in the first embodiment. Lining 3 of friction pad 33 due to deformation
The uneven wear of No. 4 is effectively suppressed.

FIG. 5 is a third embodiment of the present invention showing a modification of the second embodiment, in which the inner surface of the piston 37 has two inner cylinder holes 5 from the central axis O5 to the inner peripheral side of the disk.
0 and 50 are open, and similarly, an engagement hole 37e is opened from the central axis O5 to the outer peripheral side of the disk.

Central axes O6 of the inner cylinder holes 50,50
O6 is the center axis O5 on the disk radial direction line R passing through the rotation center of the disk rotor and the center axis O5 of the piston 37.
From the inner side of the disc to the inner circumferential side of the disc radial direction R, and are located equidistantly in the circumferential direction of the disc. , 51 are offset from the central axis O5 to the inner peripheral side of the disc, and when the caliper 31 is deformed in a C shape, the inner peripheral side of the disc of the friction pad 33 is pushed by the inner pistons 51, 51, and the pressing is performed. The area is expanded in the circumferential direction of the disk so that uneven wear of the lining 34 can be further suppressed as compared with the second embodiment.

On the rear surface of the back plate 35 of the friction pad 33, there are two projections 35 that engage with the engagement holes 37e of the piston 37.
b and 35b are provided in a protruding manner, and the protrusions 35b and 35b and the engagement hole 37e constitute a rotation stopping means 52, and the rotation stopping means 52 regulates the rotation of the piston 37. By holding 51, 51 on the inner circumference side of the disk with respect to the central axis O5, the above-described braking action can be favorably performed.

FIGS. 6 and 7 are a fourth embodiment of the present invention showing a modification of the first embodiment. In this embodiment, the piston 20 of the first embodiment is rotated 90 degrees so that the inner cylinder is rotated. The hole 21 and the inner piston 22 are deviated from the central axis O1 of the piston 20 to the disc squeezing side, and the anti-rotation means 23 composed of the protrusion 17b of the friction pad 15 and the notch 20c of the piston 20 is provided. The piston 20 is arranged on the disc entry side from the central axis O1, and the other configurations are the same as those of the first embodiment.

In the pin slide type caliper body 14 as in the present embodiment, in addition to the C-shaped deformation due to the braking reaction force, the drag torque from the friction pads 15, 15 acts as a bending moment in the clockwise direction in FIG. Then, in the caliper body 14, both the disc entry side of the action part 14a and the disc entry side of the reaction part 14b approach the disc rotor 11, and the disc entry side of the action part 14a and the reaction part 14b. Both the disc entry side and the disc tilt side are tilted away from the disc rotor 11.
On the disc entry side of the action portion 14a having a narrow distance from 5,
The piston 20 slightly tilts the cylinder hole 18 and moves forward toward the disc rotor while bending the piston seal 24 so that the piston 20 corrects the tilting of the action portion 14a and faces the friction pad 15 as much as possible. 15 back plates 1
Push the back of 7.

On the disc extension side of the action portion 14a having a large distance from the friction pad 15, the tip end surface 20a of the piston 20 floats away from the back surface of the back plate 17 together with the action portion 14a, but is biased toward the disc extension side. Positioned inner piston 22
However, by the hydraulic fluid that expands the inner hydraulic chamber 27, the inner cylinder hole 21 is pushed out separately from the piston 20, and the inner piston 22 further corrects the tilting of the action portion 14 a to correct the friction pad 15. While bending the inner piston seal 26 so as to face the inner cylinder hole 21 as much as possible.
The front end surface 22a pushes the back surface of the back plate 17 by slightly inclining and advancing toward the disk rotor.

As described above, in the action portion 14a, the piston 20 pushes the disc entry side of the friction pad 15 whose gap is narrowed by the behavior of the caliper body 14, and the behavior of the caliper body 14 also widens the gap. The outer peripheral side of the disc of the friction pad 15 is attached to the central axis O1 of the piston 20.
Then, the inner piston 22 offset by the length L1 toward the disc feeding side obtains the amount of deflection of the piston seal 24 and the inner piston seal 26, and pushes while facing the friction pad 15 as much as possible. Therefore, the caliper body 1
4 even if tilting occurs due to drag torque, the piston 20
And the inner piston 22 allow the action side friction pad 15
Uneven wear of the lining 16 can be effectively suppressed, and the caliper body 14 can be made thinner and smaller,
Even if the tilt of the caliper body 14 increases,
Corresponding to this, the lining 1 of the action portion side friction pad 15
The uneven wear of No. 6 can be prevented as much as possible.

FIG. 8 shows a fifth embodiment of the present invention, in which the caliper body 61 of the disc brake 60 has an operating portion 61.
a and 61b are provided with cylinder holes 62, 62 facing the disk rotor side, and a cylindrical piston 63 having a bottom is inserted in the cylinder hole 62. Between the bottom walls 61c and 63b,
Each hydraulic chamber 64 is defined. Also, each piston 6
3 has an inner cylinder hole 65 formed to open to the disc rotor side, and a cylindrical inner piston 6 with a bottom.
6 is housed with the front end surface 66a on the opening side facing the disc rotor side, and the bottom wall 6 of each piston 63 and the inner piston 66 is accommodated.
Inner hydraulic chambers 67 are defined between 3b and 66b.

A piston seal 68 is interposed between the fitting portion of the cylinder hole 62 and the piston 63. The piston seal 68 movably supports the piston 63 in the cylinder hole 62, and also the hydraulic pressure. The chamber 64 is liquid tightly sealed. Also, the inner cylinder hole 65 and the inner piston 66
An inner piston seal 69 is interposed between the fitting portions of the inner piston 6 and the inner piston seal 69.
6 is movably supported in the inner cylinder hole 65, and the inner hydraulic chamber 67 is liquid-tightly sealed. Each of the inner cylinder holes 65 is provided such that the central axis O8 thereof is deviated from the central axis O7 of the piston 63 by a length L4 toward the disc payout side, and has a small diameter accommodated in the inner cylinder hole 65. The inner piston 66 is configured so as to push the disc pad side of the friction pad 71 by displacing it.

The hydraulic chambers 64, 64 are provided in the disk rotor 11
Through the liquid passage pipe 70 connected to the disc entry side of the action portions 61a, 61b across the outer periphery of the piston. The hydraulic chambers 64, 67 inside and outside communicate with the liquid passage penetrating the bottom wall 63b of the piston 63. The hydraulic fluid is communicated through the hole 63c, and the pressurized hydraulic fluid from a hydraulic master cylinder (not shown) is supplied to these four hydraulic chambers 64, 64, 67, 67.

The friction pads 71, 71 are the action parts 61a,
61b is accommodated in the pad mounting recesses 74, 74,
During braking, the lining 72 and the side surface of the disc rotor 11 are slid in the disc spilling direction by the drag torque generated by the sliding contact, and the disc spill-out side end face 73a of the back plate 73.
Are brought into contact with the torque receiving surface 61d of the pad mounting recess 74 so that the braking torque of the friction pad 71 is reduced.
It is transmitted from d to the caliper body 61.

In the piston facing type caliper body 61 as in this embodiment, the friction pads 71, 71 during braking are dragged by the disc rotor 11 in the disc feeding direction, and the disc feeding side end face 72a of the back plate 72 is When supported by the torque receiving surface 61d of the pad mounting recess 74,
Since the disc entry sides of the friction pads 71, 71 are in a free state, the disc entry sides of the linings 72, 72 are wound around the disc rotor 11 to cause a leading effect of being worn earlier than other parts. In this embodiment, an inner cylinder hole 65 is provided inside each piston 66 so as to be displaced from the central axis O7 toward the disc shunting side, and the inner cylinder hole 65 is provided with the inner piston 66 having a small diameter. Is pushed out from the piston 63 and independently pushes the disc feeding side of the friction pad 71 that tries to float away from the disc rotor 11 by the leading action on the disc turning-in side. Uneven wear can be effectively suppressed.

In the present invention, the inner cylinder hole may be deviated from the center axis of the piston both on the disc inner peripheral side and the disc feeding side. In this case, it is possible to prevent uneven wear due to two of the C-shaped deformation of the caliper body and the leading action. The inner cylinder hole in the piston is
A plurality of three or more may be used.

[0052]

As described above, according to the first aspect of the present invention, when the caliper body is opened and deformed in a V shape by the braking reaction force, the disc seal side of the action side friction pad is provided with the piston seal. The piston pushes while flexing,
Similarly, the inner piston, which is provided by displacing the disk inner circumference of the action part friction pad from the center axis of the piston to the disk inner circumference, obtains the amount of deflection of the piston seal and the inner piston seal to make the friction pad as positive as possible. Since they are pushed against each other, uneven wear of the lining of the action portion side friction pad can be effectively suppressed. In addition, even if the caliper body is made thinner and smaller to reduce the weight of the car body and the C-shaped deformation of the caliper body may increase, uneven wear of the lining of the friction pad on the action part side is correspondingly dealt with. Can be prevented as much as possible.

According to the second aspect of the invention, the drag torque from the friction pad acts as a bending moment on the caliper body, and the disc entry side of the action part and the disc entry side of the reaction part approach the disc rotor. , When the caliper body is tilted so that the disc outflow side of the action part and the disc ingress side of the reaction part are separated from the disc rotor, the piston bends the piston seal on the disc ingress side of the action part side friction pad. The inner piston, which pushes while not moving, also displaces the disc extension side of the action side friction pad from the center axis of the piston to the disc extension side, and obtains the deflection amount of the piston seal and the inner piston seal. Since the friction pad is pushed so as to face it as much as possible, it is possible to effectively suppress the uneven wear of the lining of the action portion side friction pad. Further, even if the caliper body is made thinner and smaller and tilting of the caliper body is increased, it is possible to correspondingly prevent uneven wear of the lining of the action portion side friction pad as much as possible.

Further, in the third aspect of the invention, when a leading action is generated on the disc advancing side of the friction pad, the piston pushes the disc advancing side of the friction pad, and the disc advancing side of the friction pad is moved to the piston. Since the inner piston, which is provided eccentrically from the central axis of the disc to the disc squeezing side, projects and pushes more than the piston, it is possible to effectively suppress uneven wear of the lining of the friction pad.

[Brief description of drawings]

FIG. 1 is a sectional side view of a caliper body showing a first embodiment of the present invention.

FIG. 2 is a partial sectional front view of a caliper body showing the first embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of a caliper body showing a first embodiment of the present invention.

FIG. 4 is a sectional side view of a caliper body showing a second embodiment of the present invention.

FIG. 5 is a sectional front view of a caliper body showing a third embodiment of the present invention.

FIG. 6 is a sectional plan view of a caliper body showing a fourth embodiment of the present invention.

FIG. 7 is a sectional front view of a caliper body showing a fourth embodiment of the present invention.

FIG. 8 is a partially sectional plan view of a caliper body showing a fifth embodiment of the present invention.

FIG. 9 is a detailed view showing the relationship between the cylinder hole, the piston, and the piston seal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Disc brake 11 ... Disc rotor 12 ... Caliper bracket 14 ... Caliper body 14a ... Action part of the caliper body 14b ... Reaction part of the caliper body 14c ... Bridge part of the caliper body 14d ... Bottom wall of the cylinder hole 18 ... Friction pad 16 ... Lining of friction pad 15 17 ... Back plate of friction pad 18 ... Cylinder hole 20 ... Piston 20a ... Tip surface 20b of piston 20 ... Bottom wall of piston 20 20d ... Formed on bottom wall 20b of piston 20 Liquid passage hole 21 ... Inner cylinder hole 22 formed inside piston 20 ... Inner piston 22a ... Tip surface 22b of inner piston 22 ... Bottom wall of inner piston 23 ... Projection 17b of friction pad 15 and notch 20c of piston 20 Detent means 23 24 composed of and ... Stone seal 25 ... Hydraulic chamber 26 ... Inner piston seal 27 ... Inner hydraulic chamber 30 ... Disc brake 31 ... Caliper body 31a, 31b ... Working portion 31c of caliper body 31 ... Bottom wall of cylinder hole 32 ... Cylinder hole 33 ... Friction pad 34 ... Lining of friction pad 33 35 ... Back plate of friction pad 33 37 ... Piston 37a ... Piston 37 tip surface 37b ... Bottom wall of piston 37 37c ... Liquid passage hole formed in bottom wall 37b of piston 37 38 ... hydraulic pressure chamber 39 ... cylinder hole 40 ... inner piston 40a ... inner piston 40 tip surface 40b ... inner piston 40 bottom wall 41 ... inner hydraulic chamber 42 ... piston seal 43 ... inner piston seal 44 ... piston 37 engagement Anti-rotation means 50 consisting of the hole 37d and the projection 35a of the friction pad 33. Da hole 51 ... Inner piston 60 ... Disc brake 61 ... Caliper body 61a, 61b ... Action part of caliper body 61c ... Bottom wall of cylinder hole 62 ... Cylinder hole 63 ... Piston 63a ... Piston 63 tip surface 63b ... Piston 63 Bottom wall 63c ... Liquid passage hole 64 formed in bottom wall 63b of piston 63 ... Hydraulic chamber 65 ... Inner cylinder hole 66 ... Inner piston 66a ... Tip surface of inner piston 66b ... Bottom wall of inner piston 66 ... Inner hydraulic chamber 68 ... Piston seal 69 ... Inner piston seal 70 ... Fluid passage 71 ... Friction pad 72 ... Friction pad 71 lining 73 ... Friction pad 71 back plate A ... Disc rotor 11 rotation direction O1 ... Piston 22 Central axis O2 ... Central axis L1 of inner cylinder hole 21 ... Length between central axes O1 and O2 3 ... Center axis of piston 26 O4 ... Center axis of inner cylinder hole 39 L2 ... Length between center axes O3 and O4 O5 ... Center axis of piston 37 O6 ... Center axis of inner cylinder hole R ... Disc radial direction line L3 ... Length between central axes O5 and O6 O7 ... central axis of piston 63 O8 ... central axis of inner cylinder hole 65

Claims (3)

[Claims] 1. A cylinder hole is provided on the side of the disk rotor, the cylinder hole opening toward the disk rotor,
A piston is inserted into the cylinder hole to define a hydraulic chamber between the piston and the bottom of the cylinder hole, and the working fluid supplied to the hydraulic chamber advances the piston toward the disc rotor. Of the caliper body of the vehicle disc brake, which pushes the friction pad to bring the lining of the friction pad into sliding contact with the side surface of the disc rotor, thereby opening the inside of the piston toward the disc rotor. An inner cylinder hole that is offset from the center axis of the piston toward the disk inner peripheral side, and the inner piston is inserted into the inner cylinder hole so that the inner hydraulic pressure is between the inner piston and the bottom wall of the piston. An inner piston seal that defines a chamber, movably supports the inner piston between the fitting portions of the inner piston and the piston, and seals the inner hydraulic chamber in a liquid-tight manner. And a piston seal that movably supports the piston and seals the hydraulic chamber in a liquid-tight manner is interposed between the fitting portion of the piston and the cylinder hole. A caliper body for a disc brake for a hydraulic vehicle, characterized in that a through hole is bored to communicate the hydraulic chamber with the inner hydraulic chamber. 2. A disk rotor comprising: an operating portion arranged on one side of the disk rotor; a reaction portion arranged on the other side of the disk rotor; and a bridge portion connecting these across the outer circumference of the disk rotor. , A piston is inserted into a cylinder hole provided in the action portion so as to open toward the disc rotor side to define a hydraulic chamber between the piston and the bottom of the cylinder hole, and the hydraulic chamber is supplied to the hydraulic chamber. A caliper body for a vehicle disc brake that performs a braking action by moving the piston forward in the disc rotor direction with hydraulic fluid to push the friction pad and sliding the lining of the friction pad into contact with the side surface of the disc rotor. In the inside of the piston, an inner cylinder hole opening toward the disc rotor side is provided so as to be offset from the center axis of the piston toward the disc shunting side, and the inner piston hole is provided in the inner cylinder hole. To define an inner hydraulic chamber between the inner piston and the bottom wall of the piston, and movably support the inner piston between the fitting portion of the inner piston and the piston. An inner piston seal that seals the inner hydraulic chamber in a liquid-tight manner is interposed, the piston is movably supported between the fitting portion of the piston and the cylinder hole, and the hydraulic chamber is sealed in a liquid-tight manner. A disc brake for a hydraulic vehicle, characterized in that a piston seal for sealing to the inside is provided, and a fluid passage hole is formed in the bottom wall of the piston to communicate the fluid pressure chamber with the inner fluid pressure chamber. Caliper body. 3. A cylinder hole opening to the disk rotor side is provided opposite to both acting portions arranged on both sides of the disk rotor, and a piston is inserted into each of the cylinder holes to form a piston and a cylinder hole. A hydraulic chamber is defined between the bottom and the hydraulic chamber, and the hydraulic fluid supplied to the hydraulic chamber causes the piston to move forward in the direction of the disc rotor to push the friction pad. In a caliper body of a vehicle disc brake that performs a braking action by slidingly contacting a side surface of a disc rotor, an inner cylinder hole that opens toward the disc rotor is provided inside the piston, and the inner side of the piston is closer to the disc extension side than the center axis of the piston. And an inner piston is inserted into the inner cylinder hole to define an inner hydraulic chamber between the inner piston and the bottom wall of the piston. An inner piston seal that movably supports the inner piston and liquid-tightly seals the inner hydraulic chamber, between the fitting portion of the piston and the piston,
A piston seal that movably supports the piston and seals the hydraulic chamber in a liquid-tight manner is interposed between the fitting portion of the piston and the cylinder hole, and a liquid passage hole is formed in the bottom wall of the piston. A caliper body for a disc brake for a hydraulic vehicle, wherein the caliper body is bored to communicate the hydraulic chamber with the inner hydraulic chamber.