JPH08296675A - Brake wheel cylinder - Google Patents

Abstract

PURPOSE: To simply and effectively suppress the wear of a cylinder body, and to improve the economical efficiency the maintenance. CONSTITUTION: A brake wheel cylinder 10 consists of a cylinder body 16 to be arranged between brake shoes 14 opposite to each other in a wheel brake 12, and a piston 18 to slide in the cylinder body 16, and press the brake shoes 14 against a brake drum 22. A liner 26 having the wear resistance is fitted to an inner circumferential sliding surface 16a of the cylinder body 16. The liner 26 is made of the fiber reinforced metal having higher hardness than the surface hardness of the piston 18, and fixed to the inner circumferential sliding surface 16a of the cylinder body 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a brake wheel cylinder for pressing a brake shoe against a brake drum or the like.

[0002]

Brake wheel cylinders are used in braking devices for automobiles, especially in drum brakes. This brake wheel cylinder 10 is generally a cylinder body 1 arranged between opposing brake shoes 14, 14 in a wheel brake 12, as shown in FIG.
6 and a piston 18 that slides in the cylinder body 16
And the piston 18 is the brake shoe 14
Is pressed against the brake drum 22 to brake the rotation of the wheel. Conventionally, such a brake wheel cylinder 10
In Fig. 5, the piston 18 was in direct contact with the inner peripheral sliding surface 16a of the cylinder body 16 and slid as shown in Fig. 5.

[0003]

Therefore, in the brake wheel cylinder 10 of the prior art, there is a problem that the inner peripheral sliding surface 16a of the cylinder body 16 which is a friction surface is worn. In order to improve the wear resistance of the cylinder body 16 and prevent the inner peripheral sliding surface 16a from being worn,
Originally, it is desirable to make the surface hardness of the inner peripheral sliding surface 16a of the cylinder body 16 higher than the surface hardness of the piston 18. However, in reality, the cylinder body 16 has a structurally hard surface such as quenching. Difficult to handle high.

When the inner peripheral sliding surface 16a of the cylinder body 16 of the brake wheel cylinder 10 is exposed, the cylinder body 16 is exposed to moisture in the air absorbed in the brake fluid used as the hydraulic pressure source. Inner peripheral sliding surface 16
There was a problem that rust was generated in a.

In particular, in the prior art, even if only the inner peripheral sliding surface 16a of the cylinder body 16 is worn or rusted in this way, it is necessary to replace the entire cylinder body 16 for maintenance. There was a problem that the cost of

SUMMARY OF THE INVENTION An object of the present invention is to provide a brake wheel cylinder which can easily and effectively suppress the wear of the cylinder body and can be maintained at low cost in order to avoid the above problems.

[0007]

As a first means for solving the above-mentioned problems, the present invention provides a cylinder main body arranged in a wheel brake and a cylinder inside the wheel brake which slides in the cylinder main body. A brake wheel cylinder comprising a piston for pressing a friction material against a driven body, characterized in that wear resistance means is provided on an inner peripheral sliding surface of a cylinder body.

According to the present invention, in the above-mentioned first problem solving means, the wear resistant means is a liner attached to the inner peripheral sliding surface of the cylinder body, and the liner is made of a wear resistant material. The present invention provides a brake wheel cylinder characterized by the above. In this case, in particular, this liner can be formed of a fiber reinforced metal (hereinafter referred to as FRM) or a fiber reinforced resin (hereinafter referred to as FRP).

Further, the present invention provides the brake wheel cylinder according to the above first means for solving problems, wherein the wear-resistant means is a wear-resistant coating provided on an inner peripheral sliding surface of the cylinder body. Is provided. In this case, in particular, this wear-resistant coating can be formed from a ceramic sprayed layer or a chrome-plated layer.

Further, according to the present invention, in the above-mentioned first problem solving means, the abrasion resistance means is a sleeve fitted to an inner peripheral sliding surface of the cylinder body, and the sleeve is subjected to a surface hardening treatment. The present invention provides a brake wheel cylinder characterized in that

As a second means for solving the above problems, the present invention provides a cylinder body arranged in the wheel brake and a friction material in the wheel brake that slides in the cylinder body. In a brake wheel cylinder including a piston to be pressed against a driving body, a brake characterized in that a resin layer having a hardness lower than a surface hardness of an inner peripheral sliding surface of a cylinder body is formed on an outer peripheral sliding surface of the piston. A wheel cylinder is provided.

[0012]

As described above, when the wear resistance means is provided on the inner peripheral sliding surface of the cylinder body, the piston slides in the cylinder body through the wear resistance means, so that the wear of the cylinder body is effectively prevented. Can be suppressed.

Further, in this case, not only a liner is provided on the inner peripheral sliding surface of the cylinder body as a wear-resistant means, but if this liner is made of a wear-resistant material, the surface is hardened due to structure or the like due to its structure. The surface hardness of the cylinder body, which is difficult to process, can easily be made higher than the surface hardness of the piston, and the ideal state for suppressing the wear of the cylinder body can be achieved. It can be effectively suppressed.

Particularly, when the liner provided on the inner peripheral sliding surface of the cylinder body is formed of FRM or FRP,
These materials are generally harder than pistons made of aluminum or the like, and have excellent wear resistance and heat resistance, so they are suitable for use in preventing wear of sliding surfaces. By making the hardness higher than the surface hardness of the piston, the wear of the liner can be effectively suppressed.

As a wear-resistant means, if a wear-resistant coating is applied to the inner peripheral sliding surface of the cylinder body, the structure will be
The surface hardness of the cylinder body, which is difficult to harden and harden, can easily be made higher than the surface hardness of the piston, making it ideal for suppressing wear of the cylinder body. Wear of the main body can be suppressed easily and effectively.

In particular, when a ceramic sprayed layer or a chrome plated layer is used as this wear resistant coating, these ceramic sprayed layers and the like are suitable for preventing wear of the cylinder body, and therefore wear of the cylinder body is effective. Can be suppressed.

Further, when a sleeve fitted to the inner peripheral sliding surface of the cylinder body is used as the abrasion resistance means, and the surface hardening treatment is applied to this sleeve, the cylinder body itself is similarly surface hardened by hardening or the like. Even if the treatment is difficult, the surface hardening treatment can be easily applied to this sleeve. Therefore, the inner surface sliding surface of the cylinder body can be easily wear-resistant by the surface hardening treatment. The surface hardness of the cylinder body can be made higher than the surface hardness of the piston by giving it, and it can be in an ideal state to suppress the wear of the cylinder body, so that the wear of the cylinder body can be easily and effectively performed. Can be suppressed.

Further, when a resin layer having a hardness lower than the surface hardness of the inner peripheral sliding surface of the cylinder body is formed on the outer peripheral sliding surface of the piston in this way, similarly, the surface of the structure such as quenching is also structurally structured. The surface hardness of the cylinder body, which is difficult to harden, can be easily made higher than the surface height of the piston, and it can be put in an ideal state to suppress the wear of the cylinder body. Can be suppressed. Further, in this case, when a resin layer is provided on the piston, a part of the piston is resinized,
It is also possible to reduce the weight of the entire piston.

In particular, when the inner peripheral sliding surface of the cylinder body is provided with a wear resistant means such as a liner, a wear resistant coating, and a surface-hardened sleeve in this manner, the liner is replaced during maintenance of the cylinder body. Also, it is only necessary to repair the wear-resistant coating, replace the sleeve, and repair, and it is not necessary to replace the entire cylinder body, which improves the economical efficiency of maintenance.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described in detail. FIG. 1 shows a wheel brake 12 equipped with a brake wheel cylinder 10 of the present invention.
The wheel brake 12 is shown in the form of a drum brake consisting of two brake shoes 14, 14 arranged opposite the inner surface of the brake drum 22, as shown in FIG. Driving 2
One brake wheel cylinder 10 is connected to the brake drum 2
The two axes are symmetrically arranged on the left and right. Since the wheel brake 12 in the illustrated embodiment is in the form of a drum brake, as shown in FIG.
4 is a friction material, the brake drum 22 is a driven body, and the piston 18 is a friction material through the brake shoes 14, 14, and the lining 24 is a driven body. It is pressed against a certain brake drum 22.

Each of the brake wheel cylinders 10 is, as shown in FIG. 1, a cylinder body 16 arranged between two opposing brake shoes 14 in the wheel brake 12, and each of these cylinder bodies. It consists of a piston 18 which slides inside 16.

The cylinder body 16 is generally formed of a metal material such as aluminum or cast iron, and is attached to the anchor plate 20 of the wheel brake 12 as shown in FIG. Further, the piston 18 is made of aluminum or the like, and in the illustrated embodiment, as shown in FIG.
It is composed of two pistons 18A and 18B that slide in opposite directions toward one brake shoe 14. The outer ends of the pistons 18A and 18B are connected to the brake shoe 14, respectively. In FIGS. 1 and 2, reference numeral 19 indicates an adjusting screw provided on one piston 18A.

In this brake wheel cylinder 10, when the brake pedal is depressed, the brake fluid pressurized by a brake booster (not shown) is transferred to the cylinder body 16
The pistons 18 </ b> A and 18 </ b> B slide inside the cylinder body 16 toward the brake shoe 14 by the hydraulic pressure, and press the brake shoe 14 against the brake drum 22. The brake shoe 14 pressed against the brake drum 22 by the extension of the piston 18 controls the rotation of the wheel brake 12 by bringing the lining 24 attached to the outer surface of the brake shoe 14 into frictional contact with the brake drum 22.

On the other hand, when the force applied to the brake pedal is removed, the brake shoe 14 is separated from the brake drum 22 by the two return springs 25 shown in FIG. 1, and accordingly, the two pistons 18A and 18B are moved to the cylinder main body. By sliding in the directions in which they approach each other in 16, the brake fluid in the cylinder body 16 is returned to the reservoir via a brake booster (not shown), and the state shown in FIG. 1 is restored.

The brake wheel cylinder 10 of the present invention is
In particular, as shown in FIG. 2, the wear resistance means 23 is provided on the inner peripheral sliding surface 16a of the cylinder body 16. Therefore,
The piston 18 slides in the cylinder body 16 via the wear-resistant means 23, and the wear-resistant means 23 is
Since it has wear resistance, the wear of the cylinder body 16 can be effectively suppressed.

As the wear resistant means 23, a liner 26 attached to the inner peripheral sliding surface 16a of the cylinder body 16 can be used as shown in FIG. The liner 26 can impart wear resistance to the inner peripheral sliding surface 16a of the cylinder body 16. Specifically, by forming the liner 26 from a wear-resistant material, the hardness of the liner 26 is made relatively higher than the surface hardness of the pistons 18A and 18B, so that the liner 26 is resistant to wear against the piston 18. It is possible to impart sex.

The liner 26, as shown in FIG.
After being formed into a shape along the inner peripheral sliding surface 16a of the cylinder body 16, by interference fitting within the cylinder main body 16, as shown in FIG. It is fixedly installed.

Therefore, the piston 18 has the liner 2
While directly contacting with 6, it slides in the cylinder body 16 via the liner 26. In this case, in the present invention,
This liner 2 is not only provided with the liner 26
By forming 6 from an abrasion resistant material, the liner 2
Since the hardness of No. 6 is made higher than the surface hardness of the piston 18 to give the liner 26 abrasion resistance to the piston 18, the surface hardness of the cylinder body 16 that is difficult to harden due to its structure is considered to be the piston. The surface height of the cylinder body 16 can be easily made higher than that of the surface height of the cylinder body 18, and an ideal state can be obtained for suppressing wear of the cylinder body 16.

Therefore, when the piston 18 slides in the cylinder body 16, the wear of the cylinder body 16 can be suppressed easily and effectively. In particular, in the brake wheel cylinder 10 that is frequently used, it is very advantageous to provide the sliding surface with the wear resistant liner 26 in order to provide the brake wheel cylinder 10 with sufficient durability.

In this case, as the wear resistant material forming the liner 26, since the piston 18 is generally made of aluminum, for example, a composite metal having a hardness higher than that of aluminum can be used. As the composite metal, specifically, A which is a composite of carbon fiber, boron fiber, etc.
It is possible to use FRM such as 1 alloy, Mg alloy, and Ti alloy. However, it is not limited to these FRMs, and other composite metals may be used as long as the hardness can be made higher than the surface of the piston 18.

As described above, when the liner 26 provided on the inner peripheral sliding surface 16a of the cylinder body 16 is made of a composite metal such as FRM, the composite metal is generally formed of aluminum or the like as described above. The hardness is higher than that of the piston 18 and the wear resistance and heat resistance are excellent.
It is particularly suitable for preventing abrasion of the sliding surface, and the hardness of the liner 26 can be easily made higher than the surface hardness of the piston 18 to effectively suppress abrasion of the cylinder body 16.

By forming the liner 26 from a composite resin having a hardness higher than that of the piston 18, the hardness of the liner 26 is made higher than the surface hardness of the piston 18,
It is also possible to impart wear resistance to the liner 26. As the composite resin, specifically, unsaturated polyester,
FRP in which glass fibers or carbon fibers are combined with thermosetting resin such as urethane can be used. However, these F
The material is not limited to RP, and other composite resin having a hardness higher than the surface hardness of the piston 18 may be used as long as it can impart wear resistance to the liner 26. Thus, even if the liner 26 is made of a composite resin such as FRP, the wear of the cylinder body 16 can be suppressed easily and effectively.

This liner 26 is made of a composite resin, especially FR.
Also in the case of forming from P, after forming the liner 26 in a shape along the inner peripheral sliding surface 16a of the cylinder body 16,
By making an interference fit in the cylinder body 16, FIG.
As shown in, it can be fixedly attached to the inner peripheral sliding surface 16a of the cylinder body 16.

The inner peripheral sliding surface 16 of the cylinder body 16
In order to suppress the wear of a, the liner 26 needs to have abrasion resistance at least with respect to the piston 18. Therefore, as long as the hardness of the liner 26 is relatively higher than the surface hardness of the piston 18, the liner 26 is not limited to the one formed of the above FRM or FRP, and is higher than the surface hardness of the piston 18. You may form using the material of.

Another embodiment of the present invention will be described. In this embodiment, as shown in FIG. 2, as the abrasion resistance means 23, the abrasion resistance applied to the inner peripheral sliding surface 16a of the cylinder body 16 is reduced. The property coating 27 is used.

The wear resistant coating 27 can be formed of, for example, a ceramic sprayed layer. In this case, the wear resistant coating 27 can be formed by spraying ceramics on the inner peripheral sliding surface 16a of the cylinder body 16 to a predetermined thickness. Specific examples of this ceramic include Al ₂ O ₃ , Si ₃ N ₄ , SiC, ZrO ₂ and B _4.
Structural ceramics such as C can be used. These ceramics also have higher hardness than the material of the piston 18, and are excellent in wear resistance and heat resistance, and therefore are suitable for use in preventing wear of the inner peripheral sliding surface 16a of the cylinder body 16 which is a sliding surface. ing. Therefore, even if the wear resistant coating 27 made of the ceramic sprayed layer is used, the wear of the cylinder body 16 can be suppressed easily and effectively.

The wear-resistant coating 27 is not limited to the one formed from this ceramic sprayed layer, but the piston 1
If wear resistance to 8 can be imparted, other
For example, it may be formed of a chrome plating layer.

Further, another embodiment of the present invention will be described. In this embodiment, as the abrasion resistance means 23, as shown in FIG. 2, a sleeve fitted to the inner peripheral sliding surface 16a of the cylinder body 16. 29 is used. This sleeve 29
Has been surface hardened. Specific examples of the surface hardening treatment include an appropriate method such as quenching and plating.

In this case, even if the surface hardening treatment such as quenching is difficult for the cylinder body 16 itself, the sleeve 2
Since the surface hardening treatment can be easily performed on 9, the wear resistance can be easily imparted to the inner peripheral sliding surface 16a of the cylinder body 16 by the sleeve 29 subjected to the surface hardening treatment.

For this reason, the surface hardness of the cylinder body 16 can be easily made higher than the surface hardness of the piston 18 by the sleeve 29, and an ideal state for suppressing the wear of the cylinder body 16 can be obtained. Therefore, wear of the cylinder body 16 can be suppressed easily and effectively. In this case, since the sleeve 29 is subjected to the surface hardening treatment, it is not always necessary to use a wear-resistant material as the material of the sleeve 29 itself, and it can be formed of the same material as the cylinder body 16, for example. , Material cost will be low.

In the above embodiment, the abrasion resistant means 23
Although the liner 26, the wear resistant coating 27, and the sleeve 29 have been described as examples, the invention is not necessarily limited to these, and the inner peripheral sliding surface 16a of the cylinder body 16 is not limited thereto.
Needless to say, other methods may be used as long as abrasion resistance can be imparted to the inner peripheral sliding surface 16a and damage to the inner peripheral sliding surface 16a can be prevented.

Next, another embodiment of the present invention will be described with reference to FIG. 3. In this embodiment, the outer peripheral sliding surface 18a of the piston 18 has a hardness lower than the surface hardness of the inner surface of the cylinder body 16. Is formed on the resin layer 28.

As shown in FIG. 3, the resin layer 28 is formed in a shape along the outer peripheral sliding surface 18a of the piston 18, and then is tightly fitted to the outer peripheral sliding surface 18a of the piston 18 by As shown in FIG. 3, it is fixedly attached to the outer peripheral sliding surface 18a of the piston 18.

Therefore, the piston 18 slides in the cylinder body 16 via the liner 28 while the resin layer 28 provided on the outer circumference sliding surface 18a thereof contacts the inner circumference sliding surface 16a of the cylinder body 16. . In this case, in the present invention, since the hardness of the resin layer 28 is lower than the surface hardness of the piston 16, the surface hardness of the cylinder body 16 is difficult to be hardened due to the structure, such as quenching or plating. The surface height of the cylinder body 16 can easily be made relatively higher than that of the surface height of the cylinder body 18, and an ideal state for suppressing wear of the cylinder body 16 can be obtained. Therefore, the wear of the cylinder body 16 can be effectively suppressed, and at the same time,
By making part of the piston 18 resin, it is possible to reduce the weight of the entire piston 18.

Further, in the present invention, as shown in FIG. 2, a liner 26, a wear resistant coating 27, and a sleeve 29 are provided on the inner peripheral sliding surface 16a of the cylinder body 16 as the wear resistant means 23. Therefore, at the time of maintenance of the cylinder body 16, only these liners 26 need to be replaced, the wear resistant coating 27 must be repaired, and the surface-hardened sleeve must be replaced and repaired.
Since it is not necessary to replace the entire cylinder body 16, the economy of maintenance is enhanced.

In the illustrated embodiment, the brake wheel cylinder 10 having the two pistons 18A and 18B has been described as an example as shown in FIGS. 1 to 3, but the invention is not limited to this. One piston 1
It is also applicable to a brake wheel cylinder 10 having only 8 and moving the piston 18 and the cylinder body 16 in mutually opposite directions to press the brake shoe 14 against the brake drum 22. In the illustrated embodiment, the form of the drum brake is shown, but the cylinder body 1
The brake wheel cylinder 10 provided with the piston 18 that slides in 6 can be applied regardless of its type. For example, the piston 18 that slides in the cylinder body 16 can be used as a friction material pad. It can also be applied to the form of a disc brake that is pressed against a disc that is a driven body.

[0047]

According to the present invention, as described above, since the wear resistance means is provided on the inner peripheral sliding surface of the cylinder body, the piston slides in the cylinder body through the wear resistance means. Therefore, there is a practical advantage that the wear of the cylinder body can be effectively suppressed.

Further, in this case, as described above, not only the liner is provided on the inner peripheral sliding surface of the cylinder body as the wear-resistant means, but also the liner is formed of a wear-resistant material and wear-resistant to the liner. The surface hardness of the cylinder body, which is difficult to harden due to its structure due to its structure, can easily be made higher than the surface hardness of the piston, ideal for suppressing wear of the cylinder body. Therefore, it is possible to suppress the wear of the cylinder body easily and effectively.

In particular, since the liner provided on the inner peripheral sliding surface of the cylinder body is formed of FRM, FRP or the like, these materials generally have higher hardness than the piston formed of aluminum or the like, and Since it has excellent wear resistance and heat resistance, it is suitable for use in preventing wear on the sliding surface. Therefore, by making the liner hardness higher than the piston surface hardness, the liner wear is effectively suppressed. There is a real benefit that can be done.

Further, as the abrasion resistance means, as described above,
Since the inner peripheral sliding surface of the cylinder body has a wear resistant coating, the surface hardness of the cylinder body, which is difficult to harden due to its structure, can be easily made higher than the surface hardness of the piston. Since it is possible to achieve the ideal state for suppressing the wear of the cylinder body, there is a practical advantage that the wear of the cylinder body can be easily and effectively suppressed.

In particular, since a ceramic sprayed layer or a chrome-plated layer is used as the wear resistant coating, these ceramic sprayed layers and the like are suitable for preventing wear of the cylinder body, and therefore wear of the cylinder body is prevented. There is a real benefit that can effectively control.

Further, as the abrasion resistance means, as described above,
Since a sleeve fitted to the inner peripheral sliding surface of the cylinder body is used and this sleeve is subjected to a surface hardening treatment, it is difficult to harden the cylinder body itself in the same way. However, this sleeve can be easily surface-hardened. Therefore, the surface-hardened sleeve can easily give abrasion resistance to the inner peripheral sliding surface of the cylinder body to improve the surface of the cylinder body. The hardness can be made higher than the surface hardness of the piston, and the ideal state for suppressing the wear of the cylinder body can be achieved, so that the wear of the cylinder body can be easily and effectively suppressed. is there.

Further, according to the present invention, as described above, since the resin layer having a hardness lower than the surface hardness of the inner peripheral sliding surface of the cylinder body is formed on the outer peripheral sliding surface of the piston, In addition, the surface hardness of the cylinder body, which is difficult to harden due to its structure, can easily be made higher than the surface height of the piston, making it ideal for suppressing the wear of the cylinder body. Therefore, there is a real advantage that the wear of the cylinder body can be effectively suppressed, and further, a weight reduction of the entire piston can be achieved because a part of the piston is made of resin.

In particular, according to the present invention, since the liner, the wear resistant coating, and the wear resistant means such as the sleeve are provided on the inner peripheral sliding surface of the cylinder body, only the liner is replaced when the cylinder body is maintained. And repairing the wear resistant coating, replacing and repairing the sleeve only, and not the entire cylinder body, thus increasing the economic efficiency of maintenance.

[Brief description of drawings]

1 is a schematic vertical sectional view of a wheel brake including a brake wheel cylinder of the present invention.

FIG. 2 is a schematic sectional view of a brake wheel cylinder of the present invention.

FIG. 3 is a schematic cross-sectional view of another embodiment of the brake wheel cylinder of the present invention.

FIG. 4 is a schematic vertical cross-sectional view of a wheel brake including a brake wheel cylinder of the related art.

FIG. 5 is a schematic sectional view of a brake wheel cylinder of the related art.

[Explanation of symbols]

 10 Brake Wheel Cylinder 12 Wheel Brake 14 Brake Shoe 16 Cylinder Body 16a Cylinder Body Inner Circumferential Sliding Surface 18 Pistons 18A, 18B Piston 18a Piston Outer Circumferential Sliding Surface 19 Adjusting Screw 20 Anchor Plate 22 Brake Drum 23 Anti-Abrasion Means 24 Lining 25 Return Spring 26 Liner Made of Abrasion Resistant Material 27 Abrasion Resistant Coating 28 Resin Layer 29 Sleeve with Surface Hardening Treatment

Claims (7)

[Claims] 1. A brake wheel cylinder comprising a cylinder body arranged in a wheel brake and a piston which slides in the cylinder body to press a friction material in the wheel brake against a driven body. A brake wheel cylinder characterized in that wear resistance means is provided on the inner peripheral sliding surface. 2. The brake wheel cylinder according to claim 1, wherein the wear resistant means is a liner attached to an inner peripheral sliding surface of the cylinder body, and the liner is made of a wear resistant material. Brake wheel cylinder characterized by being formed. 3. The brake wheel cylinder according to claim 2, wherein the liner is formed of either fiber reinforced metal or fiber reinforced resin. 4. The brake wheel cylinder according to claim 1, wherein the wear-resistant means is a wear-resistant coating provided on an inner peripheral sliding surface of the cylinder body. Cylinder. 5. The brake wheel cylinder according to claim 4, wherein the wear resistant coating is formed of either a ceramic sprayed layer or a chrome plated layer formed on the inner peripheral sliding surface of the cylinder body. Brake wheel cylinder characterized by having. 6. The brake wheel cylinder according to claim 1, wherein the wear-resistant means is a sleeve fitted to an inner peripheral sliding surface of the cylinder body, and the sleeve is surface-hardened. Brake wheel cylinder characterized by being applied. 7. A brake wheel cylinder comprising a cylinder body arranged in a wheel brake and a piston that slides in the cylinder body and presses a friction material in the wheel brake against a driven body, the outer periphery of the piston. A brake wheel cylinder characterized in that a resin layer having a hardness lower than the surface hardness of the inner peripheral sliding surface of the cylinder body is formed on the sliding surface.