JP2769793B2 - Wheel brake cylinder - Google Patents

Abstract

PURPOSE: To provide a wheel brake cylinder capable of facilitating the assembly of a coil spring and reducing a cost. CONSTITUTION: A linking body fitted to a piston is composed of the linking body main body 3 wherein a tip part 3a is folded in the axis direction of the piston on the outer peripheral surface of a cylinder body 2; and a core material 4 which is provided by inserting a coil spring 5, and wherein one end of the material 4 abuts on or is engaged with the tip part 3a, and the other end is engaged with the engaging part 14 of an adjusting lever 6. The coil spring is stretched between a one-side spring attaching part 12 provided on the tip part 3a and the other side spring attaching part 18 provided in the vicinity of the engaging part of the adjusting lever, and the coil spring can be stretched by the principle of a lever by rotating the adjusting lever 6 with the engaging part 14 between the core material 4 and the adjusting lever 6 as a fulcrum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel brake cylinder used for a brake mechanism of an automobile, and more particularly, to a wheel brake cylinder having a function of automatically maintaining a constant shoe clearance and easily assembling. It relates to a wheel brake cylinder.

[0002]

2. Description of the Related Art A wheel brake cylinder used for a brake mechanism of an automobile has a function of pressing a brake shoe against an inner periphery of a brake drum, but also has a function of always maintaining a constant shoe clearance. is there. There are various known technologies for a wheel brake cylinder having the above functions.
Japanese Patent Publication No. 169231, Japanese Utility Model Publication No. 63-37536, and Japanese Utility Model Publication No. 41947/1994. Although each of these has a characteristic, the structure of the automatic shoe clearance adjustment section of the brake shoe related to the present invention is almost common, and has the following general structure.

An adjustment nut having a ratchet wheel outside the cylinder body is fitted to a piston slidably inserted into the cylinder body, and a connecting body is attached thereto. An adjusting bolt that engages with the brake shoe is screwed into the adjusting nut. On the other hand, an adjusting lever pivotally supported by the pivot on the cylinder body side is formed at one end with a claw that meshes with the ratchet wheel, and at the other end is formed with an engaging portion with which the other end of the connecting body is engaged. Is done. In addition, a coil spring is stretched between the engagement portion side of the adjustment lever and the connector. A ratchet rotating mechanism for rotating the ratchet wheel is constituted by the pawls, the adjusting lever, the connecting body, the coil spring, and the like. With the above structure, when the hydraulic pressure acts on the piston, the piston, the adjustment nut, the adjustment bolt, the connecting body, the ratchet wheel and the like are integrally advanced, and the brake shoe engaged with the adjustment bolt is expanded. Since the pivot of the cylinder body is at the fixed position, the coil spring is pulled with the advance, the adjustment lever is rotated, and the ratchet wheel is rotated via the pawl. Therefore, the adjustment nut rotates and the adjustment bolt is advanced by an amount corresponding to the rotation. When the clearance of the brake shoe is an allowable value, the ratchet wheel does not rotate due to elastic deformation of the adjusting lever, but when the clearance is equal to or more than the allowable value, the above-described operation is performed, and the shoe clearance is automatically adjusted.

[0004]

The shoe clearance of the brake shoe is automatically adjusted by the above-described wheel brake cylinder of the prior art, but has the following problems. That is, these connecting bodies are formed in a substantially L-shaped shape, and one end of the coil spring is engaged with one end of the connecting body, and the other end of the coil spring is engaged with the adjusting lever. In addition, since the connecting body and the adjusting lever must always be brought into pressure contact with each other, it is necessary to pull the coil spring with a strong force during the assembling and to engage the adjusting spring with the adjusting lever. Since the coil spring has a strong spring force, it is difficult to pull the coil spring by human power, and a special assembling jig is required. There is a problem that becomes.

The present invention has been made in view of the above circumstances, and has a special structure in assembling by assembling a connecting body into two parts, a connecting body to be attached to a piston and a core material inserted into a coil spring. To provide a wheel brake cylinder that can be easily assembled by anyone without the need for a jig, and can reduce costs by facilitating assembly work. It is an object of the present invention to provide a wheel brake cylinder that can correct the twist around the axis of the tire with a simple configuration and can always maintain the positional relationship between the pawl and the ratchet accurately.

[0006]

In order to achieve the above object, the present invention takes the following measures. 1, a cylinder body (2) attached to a backing plate, a piston (11) slidably inserted into the inside thereof and operated by hydraulic pressure, an adjusting nut (15) inserted into the piston, A ratchet wheel (1) which is arranged outside the cylinder body and held by the adjusting nut
6), an adjusting bolt screwed into the adjusting nut and engaged with an end of the brake shoe, and a pivot (8) fixed to the cylinder body side pivotally supported between one end and the other end. An adjusting lever (6) having a claw (22) meshing with the ratchet wheel at one end and an engaging portion (14) formed at the other end; A wheel brake cylinder for expanding or reducing the diameter of the brake shoe, comprising a connecting body engaged with the joint portion and a coil spring or the like stretched between the connecting body and the adjusting lever, wherein the connecting body Is mounted on the piston, and is provided so as to penetrate through the coil spring, and a coupling body (3) whose tip (3a) is bent in the axial direction of the piston on the outer peripheral surface of the cylinder body. To One end engages the abutment or engagement of core (4 other end to the engagement portion of the adjusting lever engages,
4 "), and the coil spring is provided with one spring engaging portion (12) provided at the distal end portion and the other spring engaging portion (18) provided near the engaging portion of the adjustment lever. )
And a guide part (23, 23) connected to the other end of the adjusting lever at the terminal end thereof, which is continuous with the engaging part (14), and guides the other end of the core material to the engaging part. 23 "), and a coil spring extending means for extending the coil spring by the leverage with the engaging portion between the core and the adjusting lever as a fulcrum while rotating the adjusting lever when assembling the coil spring. And a biasing means (7) for biasing the pawl toward the ratchet wheel is provided on one of the connecting body and the adjusting lever. The core member is formed of a rigid plate member (4) having a concave engagement groove (4a) formed at one end, and an engaged groove which can be engaged with the engagement groove at a distal end of the coupling body. (13) is formed in the engaged groove at the tip end. One end of the plate is fitted into the engagement groove and the engaged groove so that the plate and the connector body are engaged with each other. The opening (13a) is formed wider than the reference plate thickness t of the plate material by an amount corresponding to a plate thickness tolerance Δt, and the groove bottom (13e) is formed in accordance with the reference plate thickness t. A tapered portion (13c) is formed on one groove side wall (13b) continuous from the groove bottom portion (13e) to the opening via a corner portion (13f), and a part of the other groove side wall (13d). Is formed by forming a continuous concave portion (13g) at the bottom of the groove 4. In the above 2 or 3, the engaging portion (14)
It is formed so as to be engaged with the other end (4b) of the plate at a predetermined size b outside the other spring engaging portion (18). 5. In any one of the above items 1 to 4, the engaged groove (13) is formed at a position separated from the one engagement hole (12) by a predetermined dimension a, and A stepped portion (4) is provided at an intermediate portion of the plate material so that the engagement groove (4a) and the engaged groove (13) can engage with each other.
c) was formed. 6. In any one of the above items 2 to 5, the engaging portion (14) is formed by cutting out the other end of the adjusting lever, and the adjusting lever (6) is assembled when the coil spring (5) is assembled. The other end (4b) of the plate material in a state in which the engagement portion (14) is engaged with the adjustment lever by the rotation operation.
With the fulcrum as a fulcrum, the coil spring is stretched by the principle of leverage. 7. In the above item 6, the engaging portion (14) is such that the piston moves when the brake is applied, and the other end portion (4b) of the plate material is at most ΔM from one side wall (14a) of the engaging portion. Even if it does, the other side wall (14
The other side wall (14b) is configured to extend along the longitudinal direction of the plate so that the engagement between the b) and the other end (4b) of the plate can be maintained. 8. Also, the core is an axis (L ₄ ) of the coil spring.
And one end face (4a ") of the bar is formed as a flat surface orthogonal to the axis of the bar, and the one end face is formed as a flat surface. A straight portion (13 ") parallel to one end surface (4a") of the bar is formed at the contacting end portion (3a), and the guide portion has an arc-shaped end portion that is continuous with the engaging portion. Outer contour (23 ")
The arc of the outer contour portion is formed from the start portion toward the end portion and the other spring engaging portion (18) is formed.
It may be formed so as to keep away from the object. 9. In any one of the above items 1 to 8, the urging means (7) may include an engaging portion (6a) erected at the other end of the adjusting lever so as to face the pivot (8). , And the engaging portion (6) is stretched between the engaging portion and the pivot.
a) may be comprised of a biasing member (31) for pulling the pivot (8) toward the pivot (8). 10. In the above 9, the torsion member (31) twists both ends (31a, 31b) engaged with the engaging portion (6a) and the pivot (8) toward the center of the coil. It may be a coil spring (31). 11. In the above 9 or 10, the engaging portion (6a)
May be provided at a position inclined by a predetermined angle (α) from an axis (L ₂ ) of the adjustment lever parallel to the axis of the piston. 12. In any one of the above items 1 to 11, the connecting body (3) and the ratchet wheel (16) are provided at a position close to each other, and the adjusting lever (6) and the connecting body (3) do not interfere with each other. As described above, a relief portion (3c) is formed in the coupling body (3), and a ratchet rotation including an adjustment lever (6), a coil spring (5), a coupling body (3), and a core material (4). The mechanism (1) is provided at a position rotated by an angle β about the center axis O of the piston from the friction surface (30) between the brake shoe and the wheel on the cylinder body (2), and The tip (3a) of (3) may be widened toward the friction surface (30). 13. In any one of the above items 1 to 12, the ratchet wheel (16) may have a central axis (O) of the piston.
A curved portion (16b) may be formed between the ratchet portion (16a) and the ratchet portion (16a), and the ratchet portion (16a) may be provided so as to be close to the connector body (3).

[0007]

Each of the above means operates as follows. According to the first means, since the connecting member is divided into the connecting member body and the core member, the core member and the coil spring can be engaged between the adjusting lever and the connecting member body in a free length state. Since the coil spring extending means is provided at the other end of the adjusting lever, the coil spring is extended by the leverage principle by rotating the adjusting lever. By rotating the adjustment lever, the other end of the core is guided to the engagement portion along the guide portion, and is fixed by the engagement portion. The urging means always urges the claws in the direction of pressing the ratchet wheel. As described above, assembly is performed simply by rotating the adjustment lever. Further, when disassembling, the adjusting lever is easily disassembled by rotating in the direction in which the tension of the coil spring is released. According to the second means, not only can the core material be a plate material, it can be manufactured at low cost, but also the plate material is engaged with the connector body by the engaging groove and the engaged groove, so that the connector body is Can be restricted from rotating with the piston. According to the third means, the plate thickness of the plate material is set to a tolerance ± Δ with respect to the reference plate thickness t.
Even if it changes by t, the gap between the plate member and the connector body can be kept to a minimum, and the play between them can be reduced. According to the fourth means, the turning moment can be given to the adjusting lever, and the turning of the adjusting lever around the pivot can be prevented. According to the fifth means, a restoring force for correcting the torsion of the connecting body is applied, and the second body is used.
In combination with the third means and the third means, the coupling body can be held at a predetermined position, and the positional relationship between the pawl and the ratchet wheel can be always kept constant. According to the sixth means, the coil spring, which is stretched between the two spring engaging portions in the free length state, is rotated by using the other end of the plate member and the engaging portion of the adjusting lever as a fulcrum, and thereby the lever is rotated. With this principle, it can be easily stretched to a predetermined length. According to the seventh means, the piston moves excessively during brake braking,
Even if there is a gap between the other end of the plate and one of the side walls forming the engagement portion, the other end of the plate is guided by the other side wall, so that the engagement relationship between the plate and the adjustment lever Does not occur.

According to the eighth means, the core material can be a bar material, one end of the bar material is formed on a flat surface, and the connecting member body is formed as a straight portion abutting on this one end surface, and By making the axis of the coil spring coincide with the axis of the bar, the same restoring force as in the fifth means can be applied to the connecting body. Also, when assembling the coil spring, since the coil spring is gradually extended along the arc of the outer contour, the same operation as the above-described sixth means can be obtained. According to the ninth means, a rotational moment can be applied to the adjusting lever to exert a force for constantly pressing the pawl against the ratchet wheel. As the biasing member, a tension coil spring may be used, but by using a torsion coil spring as shown in the tenth means, an engaging portion can be provided near the pivot, and the adjustment lever can be made large. No need to do. According to the eleventh means, the biasing member gives a rotational moment about the axis of the adjustment lever,
Swing of the adjustment lever around the axis can be prevented. According to the twelfth means, the dimension a and the step size c can be made sufficiently large by expanding the width of the distal end portion of the connecting body to the outside of the cylinder body, and bending of the connecting body which requires strength is required. The part size k can also be increased. Further, the pawls can be provided in the vicinity of the juxtaposed side of the connecting body, so that the gap between the ratchet portion and the connecting body can be reduced, and the dimension j can be sufficiently increased. According to the thirteenth means, the ratchet portion can be brought closer to the connecting body, so that the gap (dimension e) in the twelfth means can be further reduced, and the wheel brake can be moved so that the piston faces upward. Even if the cylinder is attached, intrusion of muddy water or the like between the piston and the adjustment nut can be prevented. The above-described second to thirteenth means can be selectively provided in the first means.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention in which a plate is used as a core material. FIG. 1 (a) is a front view thereof, FIG. 1 (b) is an enlarged view of an engaging portion, and FIG. FIG. 3 is a detailed view of the groove shape in the first embodiment of the present invention, FIG. 4 is a view showing another state of engagement between the plate material and the connecting body as a core material, and FIG. Front view of the main part showing the arrangement relationship between the coupling body, ratchet wheel, pawl, and adjustment lever,
6 is a side view of the wheel brake cylinder as viewed from the direction A in FIG. 1 (a), FIG. 7 is a partial cross-sectional view of a main part of the ratchet wheel, and FIG. FIG. 8B and FIG. 9B show the first embodiment of the present invention.
Explanatory drawing of the procedure of assembling the ratchet rotating mechanism in the embodiment, FIG. 10 shows a second embodiment of the present invention in which a rod is used as a core material, a front view thereof, and FIG. 11 includes a cross-sectional view along the axis of FIG. It is a top view. In the following embodiments, "one side" or "one end" indicates the right side of the drawing (the ratchet wheel 16 side), and "other side" or "the other end" indicates the left side of the drawing.

[First Embodiment] First, the overall structure of the first embodiment will be described with reference to FIGS. A shoe clearance adjusting mechanism for automatically and always maintaining a constant shoe clearance is attached to a cylinder body 2 of a wheel brake cylinder, and a coupling body 3 attached to a piston 11 and an adjusting lever pivotally supported by a pivot 8. 6, a coil spring 5 for adjusting shoe clearance stretched between the adjusting lever 6 and the connecting body 3;
A plate member 4 as a core member through which the coil spring 5 is inserted;
2 comprises urging means 7 for constantly urging the ratchet wheel 2 into a ratchet wheel. The connected body is a plate material 4 which is a core material and a connected body 3
It is composed of

[Prerequisite Configuration] As shown in FIG. 2, a piston 11 with a seal member 10 fitted therein is slidably fitted in a cylinder hole 9 on the right side of the cylinder body 2 in the drawing. I have. A washer 17 is provided inside the piston 11.
The adjustment nut 15 is fitted through the adjustment nut 1.
5, a ratchet wheel 16 is fixed to the right end side of the figure which is separated from the cylinder body 2. A coupling body 3 is attached to the piston 11 by bending the distal end portion 3 a at right angles to the other side along the outer peripheral surface of the cylinder body 2. That is, the base 3b of the connected body 3 has
An attachment hole (not shown) is formed, and the connection body 3 is attached to the piston 11 by fitting the attachment hole to the piston 11 and caulking or welding. The bent end portion 3a is provided with one spring engaging hole 12 for engaging one end of the coil spring 5. Reference numeral 28 denotes a boot for preventing muddy water or the like from entering the cylinder hole 9.

[Structure of Core Material] The plate material 4 as a core material is formed by pressing a metal flat plate to have rigidity. Such a plate material 4 can be manufactured at extremely low cost by the above-described press molding. In addition, the plate member 4 has a stepped portion 4c at an intermediate position from one end to the other end for a reason described later. A concave engaging groove 4a is formed at one end of the plate member 4 in the plate thickness direction, and the other end 4b is formed at the other end of the plate member 4 to abut against an engaging portion 14 of the adjustment lever 6 described later. . On the other hand, a recessed engaged groove 13 is formed in the distal end portion 3a of the connector body 3 in a direction orthogonal to the engaging groove 4a, and the engaging groove 4a of the plate 4 is inserted into the engaged groove 13. It fits and engages. According to this aspect, the side surface at one end side of the plate member 4 comes into contact with the side wall of the engaged groove 13, and the rotation of the plate member 4 with respect to the connecting body 3 is restricted.

[Structure of Adjusting Lever] The adjusting lever 6 is substantially L-shaped.
A claw 22 is formed at one end to engage with the ratchet wheel 16, and an arc-shaped outer contour 2 is formed at the other end.
3, an engagement portion 14 with the other end 4b of the plate member 4 and another spring engagement hole 18 for engaging the coil spring 5 are formed. Between the one end and the other end of the adjusting lever 6 and in the vicinity of a portion where the adjusting lever 6 is bent in an L-shape, a darma-shaped shaft hole 24 in which a small-diameter hole 25 and a large-diameter hole 26 communicate with each other is formed. Have been. The adjustment lever 6 is attached to the pivot 8 by inserting the large diameter hole 26 into the pivot 8 and then shifting the adjustment lever 6 to engage the small diameter hole 25.

The outer contour part 23 as a guide part is formed in an arc shape. Then, the other end of the plate material 4 is
The other end of the plate body 4 is guided along the outer contour portion 23 to the stepped engagement portion 14 formed at the end of the arc by rotating the adjustment lever 6 in a state in which the adjustment lever 6 is in contact with the plate 3. Is done.
As shown in FIG. 1, the other end 4b of the plate member 4 is abutted and fixed to a side wall of the engaging portion 14 formed in a stepped shape. FIG. 1B is an enlarged view of the engagement portion 14. Normal,
As shown in FIG. 1A, the other end 4b of the plate member 4 is engaged with and held by both the side wall 14a and the other side wall 14b which are orthogonal to each other. If the moving amount is large, the other end 4b of the plate 4 is separated from the one side wall 14a, and a gap may be formed between the other end 4b of the plate 4 and the one side wall 14a. Therefore, in this embodiment, the other side wall 14b is larger than the maximum dimension ΔM of the gap during braking.
Of the plate member 4 and the other side wall 1
The contact position between the plate member 4 and the adjustment lever 6 is prevented from being shifted by always contacting the plate member 4b. The coil spring 5 has a strong spring force. One end of the coil spring 5 is engaged with one spring engaging hole 12 of the connecting body 3 and the other end is engaged with the other spring engaging hole 18 of the adjusting lever 6. Thereby, it is stretched between the adjustment lever 6 and the connecting body 3.
At the other end of the adjusting lever 6, an engaging member that rises at a right angle upward from the adjusting lever 6 and faces the pivot 8 at a position inclined by an angle α with respect to the axis L ₂ of the adjusting lever 6 parallel to the axis of the piston 11. A bent plate portion 6a is formed as an attachment portion.

[0015] [Configuration exerts a restoring moment on the coupling body 3] Meanwhile, the engaging portion 14 of the adjusting lever 6 and the other end portion of the plate member 4, outward from the axis L ₁ of the coil spring 5 (the cylinder body 2 (A side opposite to the side) is separated by the dimension b. That is, as shown in FIG. 1, the engagement portion between the plate member 4 and the adjustment lever 6 is formed outside the other spring engagement hole 18 by the dimension b. Accordingly, a moment in the direction indicated by the arrow D in FIG. 1 acts on the adjusting lever 6 by the spring force of the coil spring 5 stretched between the two spring engaging holes 12 and 18. 6 can be prevented from swinging. Further, an engaging portion between one end of the plate member 4 and the connector body 3 (that is, the engaged groove 13).
Is located apart dimension a (the side opposite to the cylinder body 2) also outside the axis L ₁ of the coil spring 5. That is, as shown in FIG. 1, the engagement portion between the plate member 4 and the connector body 3 is formed outside the one spring engagement hole 12 by the dimension a. Further, a stepped portion 4c having a step size c (c = ab) is formed in the middle of the plate member 4 by bending the plate member 4 to the outside of the cylinder body 2. Accordingly, the coupling body 3 is urged by the spring force of the coil spring 5 stretched between the two spring engagement holes 12 and 18.
, A rotational moment acts clockwise as viewed from the direction A. The magnitude of the rotational moment is proportional to the size of the step c, and increases as the step c increases.

This rotational moment is nothing but a restoring force for returning the connecting body 3 to its original position when the connecting body 3 rotates together with the piston 11 in the counterclockwise direction (the direction of arrow A). Therefore, even if the connecting body 3 rotates counterclockwise as viewed from the direction A together with the piston 11, a restoring force is immediately applied to the connecting body 3 due to the above-described relationship, and the connecting body 3 returns to the original position. Can be done. Since one end of the plate member 4 is engaged with the engaged groove 13 by the engaging groove 4a, when returning to the original position, the plate member 4 does not try to rotate any more but is held at that position. That is, the position of the connector body 3 is always kept constant by the restoring force and the engagement between the plate member 4 and the connector body 3. The conventional connecting body is simply connected to the connecting body 3 and the plate 4.
With only the split configuration, the connecting body 3 rotates together with the piston during braking, and the connecting body 3 is twisted with respect to the adjustment lever 6.
There is a problem in that the positional relationship between the pawls 22 and the pawls 22 deviates, making it impossible to accurately adjust the shoe clearance. In the present invention, this problem has been solved by taking the above simple means.

[Details of Shape of Engagement Groove 13] For the reasons described above, it is desirable that one end of the plate member 4 and the engagement groove 13 be engaged with each other as precisely as possible. However, the thickness of a metal flat plate delivered from a steel plate maker as a raw material of the plate material 4 usually has an allowable error (Δt) of about 10% with respect to the reference plate thickness (t). Therefore, when the groove width of the engaged groove 13 is formed in accordance with the reference plate thickness (t), a gap is generated between the groove side wall and the plate member 4 when the allowable error Δt is negative. Conversely, when the allowable error Δt is positive, one end of the plate member 4 cannot be inserted into the engaged groove 13. Therefore, in this embodiment, the groove shape of the engaged groove 13 is devised as follows so that any thickness can be dealt with the minimum positional deviation as long as the thickness is within the tolerance. did. That is, as shown in FIG.
A part of one side wall 13b following the opening 13a from e is formed as a tapered portion 13c so that the width of the opening 13a is slightly widened. The width of the opening 13a may be formed slightly larger than the value obtained by adding the allowable error Δt to the reference plate thickness t. In addition, a part of the other side wall 13d is formed with a recess 13g that is continuous with the groove bottom 13e.

The formation of the engaged groove 13 as described above acts as follows. When the plate 4 has the reference plate thickness t, as shown in FIG.
Is engaged at a corner portion 13f between the groove bottom portion 13e and the tapered portion 13c, and the side surface of the plate member 4 contacts the other side wall 13d. When the plate thickness is smaller than the reference plate thickness t by Δt, as shown in FIG. 3B, one end of the plate material 4 enters the engaged groove 13 from the diagonally lower right in the figure.
The groove bottom of the engagement groove 4a of the plate member 4 is engaged at the corner 13f between the tapered portion 13c and the groove bottom 13e. In addition, the side surface of the plate member 4 contacts the other side wall 13d. When the sheet thickness is Δt larger than the reference sheet thickness t, as shown in FIG.
And the bottom of the engagement groove 4a of the plate 4 engages with the corner 13f of the groove bottom 13e, and the side surface of the plate 4 contacts the other side wall 13d near the recess 13g.

[Another Mode for Generating Restoring Moment] The plate member 4 may be a plate member 4 'having a stepped portion 4c' having a step size c bent toward the cylinder body 2 side. In this case, the engaged groove 1 is located at a position separated from the one spring engaging portion 12 by a dimension a near the cylinder body 2.
3 'is formed, and the plate material 4' is formed by the engaged groove 13 '.
And the connector body 3 are engaged with each other. Plate 4 '
Since the engaging portion 14 between the other end 4b 'and the adjustment lever 6 is the same as that of the previous embodiment, the step size c of the stepped portion 4c' can be made larger than that of the previous embodiment. In this case, there is a relationship of c = a + b). Since the direction of the stepped portion 4c 'is opposite to that of the above embodiment, the rotational moment acting on the connecting body 3 is in the direction A (FIG. 1).
See counter-clockwise direction. Therefore, in the case of this embodiment, the shape of the engaged groove 13 'provided in the connecting body 3 is opposite to that of the above-mentioned embodiment, that is, in FIG. The engagement groove 13 is inverted.

[Structure of the urging means 7] Next, the adjusting lever 6
The urging means 7 that constantly urges the pawl 22 toward the ratchet wheel 16 will be described. The urging means 7 includes a bent plate portion 6a and a torsion coil spring 31, as shown in FIG. The torsion coil spring 31 has a double-wound coil shape, and has locking portions 31a and 31b formed at both ends by bending. One locking portion 31a is hooked on the reduced diameter portion of the pivot 8, and the other locking portion 31b is hooked on the bent plate portion 6a of the adjustment lever 6. Since the coil spring force acts on the torsion coil spring 31, the bent plate portion 6a is constantly pulled toward the pivot 8. Thereby, the adjustment lever 6
, A rotational moment acts in the counterclockwise direction in FIG. 2 around the pivot 8 (the direction of action of the rotational moment is indicated by an arrow B).
), The pawl 22 is pressed against the ratchet wheel 16.

Further, at a position eccentric from the axis L ₂ by an angle alpha, since attracted bent plate portion 6a on the pivot 8 side by a torsion coil spring 31, the adjusting lever 6 Figure 1
(A) A rotational moment acts in the direction of the middle arrow C. Therefore, even when vibration or shock at the time of sudden braking is applied, the adjustment lever 6 is hard to swing, and the swing at the time of operation of the shoe clearance adjustment mechanism accompanying the stroke of the piston is prevented,
While preventing the occurrence of invalid stroke of the piston,
Even if it swings, it can return to the original position. further,
Since the torsion coil spring 31 urges the adjusting lever 6 in a direction in which the pivot 8 engages with the small-diameter hole 25, the engagement position between the pivot 8 and the adjusting lever 6 is hard to shift even when vibration or impact is applied. In addition, it is possible to prevent an unexpected accident in which the adjustment lever 6 is detached from the large-diameter hole 26 due to the above-described vibration or impact. Further, since the small-diameter hole 25 of the adjustment lever 6 is drawn toward the pivot 8, no gap is generated.
The invalid stroke of the piston can be prevented.

The urging means 7 is not limited to the one described above as long as it can always urge the pawl 22 toward the ratchet wheel 16. For example, the torsion coil spring 31
May be replaced with a normal tension coil spring. As disclosed in Japanese Utility Model Laid-Open Publication No. 63-37536, a stepped portion is provided at the other end of the adjustment lever 6, and the adjustment lever 6 is provided. A similar effect can be obtained by offsetting the line of action of the coil spring 5 with respect to the fulcrum (the pivot 8) at which.

[Regarding Swing Angle β] FIGS.
FIG. 5 is a diagram showing a positional relationship between a ratchet rotation mechanism 1 composed of an adjustment lever 6, a coil spring 5, a connecting body 3, a plate member 4, and the like, and a cylinder body 2. FIG. FIG. 6 is a side view of the wheel brake cylinder as viewed from the direction A in FIG. As shown in the drawing, the ratchet rotating mechanism 1 is inclined by an angle β in a direction away from the friction surface 30 with respect to an axis L ₃ passing through the center axis O of the piston and parallel to the friction surface 30 between the brake shoe and the drum (not shown). It is provided. The reason for providing such an angle β is as follows. In order to prevent the ratchet wheel 16 from contacting the friction surface 30 even when the piston 11 advances in FIG.
When the piston 11 is in the retracted state, the dimension j between the ratchet portion 16a of the ratchet wheel 16 and the friction surface 30, that is, the movable range of the piston 11 needs to be sufficiently large. To make the dimension j sufficiently large, the ratchet portion 1
The size e of the gap between the connector body 6a and the connector body 3 is made as small as possible, and the ratchet portion 1 is positioned close to the connector body 3.
6a must be provided.

When the size e of the gap is reduced, the claw 2
2 comes close to the cylinder body 2 side and the connecting body 3 and the pawl 2
Therefore, a clearance 3c must be formed between the claw 22 and the connector body 3 by forming an escape portion 3c in the connector body 3 because of interference. Dimension d of the gap, in order to reliably engaged the pawl 22 to the ratchet portion 16a, the pawl 22 must be provided so as to be positioned above (the friction surface 30 closer) than the axis L _3. However, from the positional relationship between the friction surface 30 and the cylinder body 2, when the relief portion 3c is provided, the width of the distal end portion 3a and the dimension k of the bent portion are regulated by that much, and the width of the distal end portion 3a and The dimension k cannot be made sufficiently large. In this case, the dimension a cannot be made sufficiently large, so that the restoring force of the connecting body 3 does not act sufficiently, and also the bent portion cannot have sufficient strength. Therefore, in order to achieve the contradictory purpose of ensuring the width of the distal end portion 3a as large as possible while providing the gap of the dimension d, in this embodiment, the ratchet rotation mechanism 1 is connected to the center axis O of the piston 11 in the present embodiment. It was tilted around by an angle β to increase the distance from the friction surface 30. By providing the inclination of the angle β, the width of the connecting body 3 and the distal end portion 3a can be increased, and as a result, the dimension f in FIG. 6 can be increased. Can be increased. Preferably, the angle β is in the range of about 10 ° to 20 °.

[Waterproof Structure of Ratchet Wheel] Next, a waterproof structure of the ratchet wheel 16 will be described. FIGS. 7A and 7B are partially enlarged cross-sectional views of the ratchet wheel 16 and the piston 11, in which FIG. 7A is an example in which a curved portion 16b is provided, and FIG. 7B is a general one in which the curved portion 16b is not formed. In the ratchet wheel 16 of (a), the ratchet portion 16 is positioned from the center axis O (see FIG. 6) of the piston 11.
A curved portion 16b is formed over the entire circumference so that the ratchet portion 16a approaches the connector body 3 at a radially intermediate portion of the ratchet wheel 16 up to a. The wheel brake cylinder is generally provided in the wheel so that the central axis O of the piston 11 is up and down. In particular, the piston 11 is turned upward (the state shown in FIGS. 7A and 7B). When attached, muddy water or the like that has penetrated into the wheel travels through the ratchet wheel 16 and penetrates between the piston 11 and the adjusting nut 15 from the ratchet portion 16a, and the adjusting nut 15 rusts to activate the shoe clearance adjusting mechanism. It may disappear.

As shown in FIG. 7 (a), in the case where the curved portion 16b is formed, muddy water dripped on the ratchet wheel 16 is quickly absorbed by the ratchet wheel 1 by the curved portion 16b.
6, it is possible to effectively prevent muddy water from traveling along the inside of the curved portion 16b (to the side of the piston 11) and entering between the piston 11 and the adjustment nut 15, thereby improving reliability. There is a feature that a high wheel brake cylinder can be obtained. Further, by providing the curved portion 16b as described above, there is a feature that the dimension e can be further reduced and the dimension j can be further increased. Note that the connection between the connecting body 3 and the piston 11 may be performed by caulking as shown in (b) or by welding as shown in (a). In the case of connection by caulking, the base 3 is protruded from the end face of the piston 11 by caulking 11a.
a to prevent water droplets dropped on a from flowing inside and entering between the piston 11 and the adjustment nut 15.
In the case of welding and joining, as shown in FIG.
A similar effect can be obtained by bending the end of the upper part upward.

[Operation of the first embodiment] Next, the first embodiment
The operation of the embodiment will be described. FIGS. 8 and 9 are explanatory views of the procedure for assembling the shoe clearance adjustment mechanism 1, showing the positional relationship between the respective members at the start of the operation for assembling the coil spring, the core material, the connecting body, the adjustment lever, and the like.
FIG. 4 is a diagram showing a state in which a coil spring is extended with an engagement portion between a plate member and an adjustment lever as a fulcrum. Cylinder body 2
Is completed, the plate member 4 as the core material, the coil spring 5 and the adjustment lever 6 are assembled. As shown in FIG. 8, first, one end of the plate member 4 is fitted into the engaged groove 13 of the connecting body 3, and one end of the coil spring 5 in the free length state is engaged with the one spring engaging hole 12. . Further, the other end 4b of the plate member 4 is arranged in contact with the outer contour portion 23 of the adjustment lever 6, and the other end of the coil spring 5 is engaged with the other spring engagement hole 18 of the adjustment lever 6. . In this case, since the adjusting lever 6 can be arranged at an arbitrary position as described above, both ends of the coil spring 5 can be engaged with the spring engaging holes 12 and 18 in a free length state. Further, the other end 4b of the plate member 4 can be arranged on the arc of the outer contour portion 23 at a position where it does not interfere with the coil spring 5.

Next, as shown in FIG. 9, the adjustment lever 6 is rotated counterclockwise. The other end 4b of the plate member 4 is relatively moved toward the end of the arc while being guided along the arc shape of the outer contour portion 23 with the turning operation of the adjustment lever 6. When the large-diameter hole 26 of the adjustment lever 6 is slightly short of fitting into the pivot 8, the other end 4 b of the plate member 4 becomes the stepped engagement portion 1.
4 and engages. Thereafter, the adjusting lever 6 is rotated about the contact point between the plate member 4 and the engaging portion 14 as a fulcrum, and the coil spring 5 is stretched to a predetermined spring force by the leverage principle. And it is inserted into the pivot 8 from the large diameter hole 26. Finally, the torsion coil spring 31 is assembled to the state shown in FIG. 1, and the operation of assembling the ratchet rotation mechanism 1 is completed.
The above operation hooks both ends of the coil spring 5 in a free length state between the spring engaging holes 12 and 18, and causes the other end 4b of the plate body 4 to abut on the outer contour portion 23 at a position where it does not interfere with the coil spring 5. It is sufficient to simply rotate the adjustment lever 6 in the counterclockwise direction, and it is unnecessary to extend the coil spring 5 with a large force using a special tool or the like as in the prior art.

The ratchet rotating mechanism 1, which has been assembled as described above, has the ratchet wheel 16 and the pawl 22 due to the distance a, b, the restoring force of the connected body 3 by the stepped portion 4c and the action of the moment by the torsion coil spring 31. Is accurately and reliably engaged, and the twist of the coupling body 3 around the piston axis line due to the rotation of the piston 11 at the time of brake braking is corrected, and accurate shoe clearance adjustment becomes possible. When removing the plate member 4, the adjusting lever 6, the coil spring 5, and the like from the cylinder body 2, the above procedure may be reversed.

[Second Embodiment] Next, a second embodiment of the present invention will be described. In the second embodiment, the plate member 4 in the first embodiment is used.
10 and 11 show a second embodiment of the present invention. In this embodiment, the same reference numerals as in FIGS. 1 and 2 are used. In the second embodiment, the core is a bar 4 ″ formed from a round bar-shaped member. Tip 3a of connector body 3
And "one end surface 4a of the" abutting bar 4 "is formed as a flat surface perpendicular to the axis L ₄ of the. Other hand, bars 4" bar 4 to the distal end portion 3a abuts the, It is formed as a straight portion 13 "parallel to one end face 4a" of the bar 4 ".

At the other end of the bar 4 ", a concave groove 4b" is formed, and this groove 4b "is formed into an arc-shaped outer contour portion 23".
Abuts on an engaging portion 14 "formed continuously at the end of the coil spring 5. A spring engaging hole 12" for engaging both ends of the coil spring 5 and a notch is formed at the other end of the adjusting lever 6 ". and a spring engaging portion 18 ", the bar 4" are arranged on the same axis with the axis L ₄ of. the outer contour 23 'is
It is formed so as to gradually move away from the engaging portion 18 ″ from the start of the arc toward the terminal end where the engaging portion 14 ″ is formed. In the second embodiment, the urging means 7, the swing angle β, the waterproof structure of the ratchet wheel and the like can be provided in the ratchet rotating mechanism 1 ″ as in the first embodiment. Are as described above, and will not be described here.

The one end face 4a "of the bar 4" is pressed against the linear portion 13 "by the spring force of the coil spring 5. In this embodiment, when the connecting body 3 tries to rotate together with the piston, the bar 4". End surface 4a "of the coil spring 5 stretched on the same axis as the bar 4", the spring force of the coil spring 5 is extended with the end surface 4a "and the straight portion 1".
3 "always acts in a direction in which the cylinder body 2 is brought into close contact, so that a restoring force acts on the connecting body 3 in this case. The coil spring 5 is attached to the cylinder body 2 in the clockwise direction and the counterclockwise direction, as in the case of the first embodiment.
The adjusting lever 6 "is arranged so that the bar 4" is in contact with the 3 ", and both ends of the free length coil spring 5 are engaged with the spring engaging holes 12" and the engaging portions 18 ". 6 "may be turned counterclockwise. As shown by the phantom line (two-dot chain line) in FIG. 10, when the other end of the bar 4 "is engaged with the outer contour 23" and the adjustment lever 6 "is rotated, this principle is applied along the arc. The coil spring 5 is gradually extended,
Eventually, the rod 4 "is engaged with the adjusting lever 6" at the engaging portion 14 ".

Although the preferred embodiment of the present invention has been described, in the characteristic portion of the present invention in which the connecting body is composed of the connecting body 3 and the core member 4, the above-described engaged groove 13 is provided.
The groove shape, structure rotational moment has to be applied to the "adjustment lever 6 by decentering the engagement portion of the by the dimension b minutes" from the axis L ₁ of the coil spring 5 adjusting lever 6 and plate 4, the plate 4 It is optional whether or not to provide a configuration in which the stepped portion 4c is provided in the middle part.

[0034]

According to the present invention, the following remarkable effects are obtained. 1) The work of connecting a coil spring having an extremely strong spring force while pulling it using a special jig or the like becomes completely unnecessary,
A coil spring can be engaged with the adjusting lever and the coupling body in a free length state, and by rotating the adjusting lever, the coil spring can be stretched and attached according to this principle. Therefore, workability is greatly improved, and work efficiency is improved. 2) By displacing or aligning the axis of the coil spring with the axis of the core material, a restoring moment acts on the coupling body so that the torsional force acting on the coupling body during braking or the like is reduced. Corrected, the precise positional relationship between the pawl and the ratchet wheel is maintained, and precise shoe clearance can be maintained. 3) By the urging means, the engagement between the ratchet wheel and the pawl of the adjusting lever is always and surely performed, and the correct brake shoe can be adjusted. 4) A ratchet wheel having a curved portion improves drainage of muddy water even when the piston is mounted upward, and makes it difficult for muddy water to enter between the piston and the adjustment nut. Malfunction of the shoe clearance adjustment mechanism due to rust hardly occurs, and the reliability of the wheel brake cylinder can be improved. 5) When the ratchet rotating mechanism is provided at a position inclined by an angle β from the center axis of the piston, the ratchet portion, the claw, and the connecting body can be provided at positions close to each other.
The wheel brake cylinder becomes compact and the movable range of the piston can be increased.

In particular, the case where the core material is formed of a plate material not only can be manufactured at low cost but also has the following effects. By engaging the plate and the adjustment lever at a position eccentric from the axis of the coil spring by a distance b, a rotational moment acts on the adjustment lever, and it is possible to eliminate play around the pivot axis when the adjustment lever returns. When a stepped portion is provided in the middle of the plate material and is engaged with the connecting body at a position a distance away from the axis of the coil spring, the connecting body has a rotational moment, that is, the connecting body rotates together with the piston. A restoring force for correcting the torsion caused by the movement can be applied. In the case where the engaged groove is formed as in claim 3, even if the plate thickness fluctuates within the reference plate thickness t ± Δt, the plate material and the engaged groove are precisely displaced with a minimum displacement with no gap. Can be engaged. The effects (1) to (3) can be obtained only by appropriately selecting the shape of the plate, the shape of the engagement groove, the position of engagement between one end of the plate and the adjustment lever, or the position of engagement between the other end of the plate and the connecting body. Therefore, the configuration of the wheel brake cylinder does not become complicated, and the overall configuration does not become large. When the ratchet rotation mechanism is provided at a position inclined by an angle β from the center axis of the piston, it is possible to increase the dimension a and apply a sufficient restoring force against torsion to the coupling body.

[Brief description of the drawings]

FIG. 1 is a front view of a wheel brake cylinder according to a first embodiment of the present invention, and FIG. 1B is an enlarged view of an engagement portion.

FIG. 2 is a top view in which a part of the wheel brake cylinder is cut away according to the first embodiment of the present invention.

3A and 3B are detailed views showing a groove shape and a state of engagement with a plate material according to the first embodiment of the present invention, wherein FIG. 3A shows a case where the plate material has a reference plate thickness t, and FIG. When t−Δt,
(C) shows a case where the plate thickness is t + Δt.

FIG. 4 shows another embodiment of the mode of engagement between the connector body and the plate member.

FIG. 5 is a plan view of a main part of the ratchet rotating mechanism 1. FIG.

FIG. 6 is a side view of the wheel brake cylinder.

FIGS. 7A and 7B are partial cross-sectional views of a main part of the ratchet wheel. FIG. 7A shows a ratchet wheel provided with a curved portion at an intermediate portion in the radial direction, and FIG. is there.

FIG. 8 is a diagram showing a positional relationship of each member at the start of an operation of assembling a coil spring, a core material, a connecting body, an adjustment lever, and the like according to the operation of the first embodiment of the present invention.

FIG. 9 is an explanatory diagram of a procedure of extending a coil spring with an engagement portion between a plate member and an adjustment lever as a fulcrum according to the operation of the first embodiment of the present invention.

FIG. 10 is a front view of a second embodiment of the present invention.

FIG. 11 is a top view of a wheel brake cylinder according to a second embodiment of the present invention, with a part thereof cut away.

[Explanation of symbols]

1, 1 "ratchet rotating mechanism 2 cylinder body 3 linked body 3a tip 3b base 3c relief 4, 4 'plate (core) 4" rod 4a engagement groove 4b other end 4c stepped portion 5 coil spring 6 , 6 ″ adjusting lever 6a bending plate portion (engaging portion) 7 urging means 8 pivot 9 cylinder hole 10 sealing member 11 piston 12 one spring engaging hole 13 engaged groove 15 adjusting nut 16 ratchet wheel 16a ratchet portion 16b Bending part 18 The other spring engaging hole 22 Claw 23 Outer contour part (guide part) 24 Shaft hole 25 Small diameter hole 26 Large diameter hole 31 Torsion coil spring (biasing member) B, C, D Operating direction of rotational moment [ Dimensions of each part] a Distance between one spring engaging hole and the engaged groove b Distance between the other spring engaging hole and the engaging part c Step dimension d Clearance between the adjusting lever and the coupling body e The gap between the ratchet and the connector body j The distance between the ratchet and the friction surface when the piston is in the retracted state (movable range of the piston) k The dimensions of the bent part of the connector body

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16D 65/24 F16D 65/56

Claims (13)

(57) [Claims] 1. A cylinder body (2) attached to a backing plate, a piston (11) slidably inserted into the cylinder body and operated by hydraulic pressure, and an adjustment nut (15) inserted into the piston. A ratchet wheel (16) disposed outside the cylinder body and fixed to the adjustment nut; an adjustment bolt screwed to the adjustment nut and engaged with an end of a brake shoe; and fixed to the cylinder body side. A pivot (8) is pivotally supported between one end and the other end, and the one end has a claw (22) that meshes with the ratchet wheel, and the other end has an engaging portion (14). An adjusting lever (6), a connector attached to the piston and engaged with the engaging portion of the adjusting lever, and a coil spring and the like stretched between the connecting member and the adjusting lever. A wheel brake cylinder for expanding or reducing a diameter of the shoe, wherein the connecting member is attached to the piston, and a tip (3a) is bent in an axial direction of the piston on an outer peripheral surface of the cylinder body. A core member (4, 4) provided so as to penetrate the main body (3) and the coil spring, one end of which comes into contact with or engages with the distal end, and the other end engages with the engaging portion of the adjusting lever. , 4 ″), and the coil spring is provided with one spring engaging portion (1
2,12 ") and the other spring engaging portion (18, 18") provided near the engaging portion of the adjusting lever, and the other end of the adjusting lever has a terminal portion. At the engaging portion (1).
4, 14 "), and a guide portion (23, 23") for guiding the other end of the core material to the engaging portion is formed, and the adjusting lever is rotated when the coil spring is assembled. Coil spring extension means for extending the coil spring by a lever principle with an engagement portion between the core material and the adjustment lever as a fulcrum is provided.Either the coupling body or the adjustment lever is provided with the claw. A wheel brake cylinder provided with a biasing means (7) for biasing the ratchet wheel. 2. The core material has a concave engagement groove (4) at one end.
a) is formed of a rigid plate material (4, 4 ') formed with engagement grooves (13, 13') which can be engaged with the engagement grooves at the tip of the connecting body. One end of the plate material is fitted into the engaged groove at the tip end, and the plate material and the connecting body main body are engaged with the engaging groove and the engaged groove. Item 2. The wheel brake cylinder according to item 1. 3. The opening (13a) of the engaged groove (13, 13 ') is formed to be wider than the reference plate thickness t of the plate material by an amount corresponding to a plate thickness tolerance Δt. The bottom portion (13e) is formed in accordance with the reference plate thickness t, and a taper portion (13c) is formed on one groove side wall (13b) which is continuous from the groove bottom portion (13e) through the corner portion (13f) to the opening. 3. The wheel brake cylinder according to claim 2, wherein a recess (13g) is formed in a part of the other groove side wall (13d) so as to be continuous with the groove bottom. 4. The engaging portion (14) is engaged with the other end portion (4b) of the plate material outside the cylinder body (2) by a predetermined dimension b from the other spring engaging portion (18). The wheel brake cylinder according to claim 2 or 3, wherein the wheel brake cylinder is formed so as to fit with each other. 5. The engagement groove (13, 13 ') is formed at a position separated by a predetermined dimension a from the one engagement hole (12), and the engagement groove of the plate member is formed. (4a) is formed with a stepped portion (4c, 4c ') having a step size c at an intermediate portion of the plate material so that the engaged groove (13, 13') can be engaged. The wheel brake cylinder according to any one of claims 2 to 4, wherein: 6. The engaging portion (14) is formed by cutting out the other end of the adjusting lever, and is rotated by the rotating operation of the adjusting lever (6) when the coil spring (5) is assembled. The coil spring is stretched on the principle of leverage with the other end (4b) of the plate being engaged with the adjustment lever at an engagement portion (14) as a fulcrum. The wheel brake cylinder according to any one of claims 2 to 5. 7. The other end (4b) of the plate material, wherein the engagement portion (14) is moved by the piston when a brake is applied.
May be separated from the one side wall (14a) of the engaging portion by a maximum of ΔM, while maintaining the engagement state between the other side wall (14b) and the other end (4b) of the plate material. The wheel brake cylinder according to claim 6, wherein the other side wall (14b) is extended along a longitudinal direction of the plate material so as to be able to be performed. 8. The core material includes an axis (L) of the coil spring.
₄ ) A bar (4 ") arranged on the same axis as that of the bar, one end surface (4a") of the bar is formed as a flat surface orthogonal to the axis of the bar, and the one end surface is formed. Abuts on one end face (4) of the rod material.
a ") is formed, and the guide portion is formed as an arc-shaped outer contour portion (23") which is continuous with the engaging portion at the end portion, and the arc of the outer contour portion is formed. 2. The wheel brake cylinder according to claim 1, wherein the wheel brake cylinder is formed so as to move away from the other spring engaging portion (18 ″) from the start portion toward the end portion. 3. 9. The urging means (7) is provided with the pivot (8).
And an engaging portion (6a) erected at the other end of the adjusting lever so as to face the connecting lever, and the engaging portion (6a) stretched between the engaging portion and the pivot. The wheel brake cylinder according to any one of claims 1 to 8, further comprising: an urging member (31) that pulls the urging member toward the side. 10. The biasing member (31) has opposite ends (3) engaged with the engaging portion (6a) and the pivot (8).
The wheel brake cylinder according to claim 9, characterized in that the wheel brake cylinder (31) is a torsion coil spring (31) that winds and biases 1a, 31b) toward the coil center. 11. The engaging portion (6a) is provided at a position inclined by a predetermined angle (α) from an axis (L ₂ ) of the adjustment lever parallel to an axis of the piston. The wheel brake cylinder according to claim 9 or 10, wherein 12. The coupling body (3) and the ratchet wheel (16) are provided in close proximity to each other, and the coupling body (3) does not interfere with the adjusting lever (6) and the coupling body (3). A relief part (3c) is formed in (3), and a ratchet rotation mechanism (1) including an adjustment lever (6), a coil spring (5), a connecting body (3), and a core material (4) includes: From the side of the friction surface (30) between the brake shoe and the wheel on the cylinder body (2), the center axis O of the piston
The tip (3a) of the connecting body (3) is widened toward the friction surface (30), provided at a position rotated by an angle β around the center. A wheel brake cylinder according to any one of the eleventh to eleventh aspects. 13. The ratchet wheel (16) includes:
Center axis (O) of the piston and ratchet part (16a)
13. A curved portion (16b) is formed between the first member and the second member, and the ratchet portion (16a) is provided so as to be close to the connecting body (3) side. The wheel brake cylinder according to any one of the above.