JP4425492B2 - Drum brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drum braking device of high durability capable of preventing the abrasion of a stationary member on which a crank mechanism as a shoe expanding device is placed, providing the stable braking performance over a long period, and preventing the generation of abnormal noise. SOLUTION: This drum braking device is provided with the crank mechanism 22 composed of a brake lever 24 and a strut 23 for expanding and operating a pair of brake shoes 12, 13, and the crank mechanism 22 is provided with shims 30 respectively placed between sliding contact faces 24f, 23f of the brake lever 24 and the strut 23 moving in parallel to a back plate 11 while pressed to the back plate 11 direction, and head parts of mounting bolts 20, 11.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drum brake device including a crank mechanism for extending a pair of brake shoes, and more particularly to a structure in which the crank mechanism slides smoothly on a stationary member.
[0002]
[Prior art]
As an example of a drum brake device having a crank mechanism for extending a pair of brake shoes, for example, a device disclosed in Japanese Patent Application Laid-Open No. 6-337027 is known. A drum brake device having a crank mechanism as the shoe expansion device will be briefly described with reference to FIGS . Incidentally, as used in the description "left", "right" shall in FIGS.
[0003]
A pair of brake shoes 12 and 13 are movably mounted by shoe hold mechanisms 14 and 15 on a back plate 11 fixed to the stationary part 10 of the vehicle body. Two brake shoes 12 and 13, together with the lower adjacent ends are supported on the standing portion 16a of the anchor block 16 of substantially L-shaped in its FIG 8, another possible force transmission those upper adjacent ends Te than in the adjuster 17 These abutting states are maintained by a pair of upper and lower shoe return springs 18, 19 that are connected in contact and stretched between the brake shoes 12, 13.
[0004]
The anchor block 16 in this example has a seat portion 16b attached to the stationary portion 10 of the vehicle body with mounting bolts 20 and 21 with the back plate 11 in between, and these constitute a stationary member. However, the anchor block 16 may be fixed directly to the back plate 11 in some cases.
[0005]
A crank mechanism 22 that expands one opposite side of the brake shoes 12 and 13 in FIG. 8 includes a strut 23, a brake lever 24, and a shaft support pin 25, and a standing portion 16 a of the anchor block 16. The brake shoes 12 and 13 are disposed adjacent to each other with slight play.
[0006]
The strut 23 is composed of a single plate body, and is provided with a bridging portion 23a in the middle portion in the longitudinal direction in FIG. 8 and is bent into a U-shape with a lower opening except for the left contact end portion. , 23b. The facing pieces 23b and 23b form a wide gap 23c in the middle portion in the longitudinal direction, and a narrow gap 23d continuous with the wide gap 23c at the right end. Further, the left end portion is closely joined by welding or the like, and a shoe engagement groove 23e that is operatively engaged with the left brake shoe 12 is formed therein. However, the close contact and integration of both the left end portions 23b and 23b are intended to prevent the opening of the mouth and the contact engagement portion from becoming loose, but are not essential elements.
[0007]
The brake lever 24 is composed of two overlapping plates, and is accommodated in the gaps 23c and 23d of the strut 23. The right half sides of both plates are closely integrated by welding or the like, and a shoe engagement groove 24a that is operatively engaged with the right brake shoe 13 is formed therein. A projection (base) 24 b on the upper side of the shoe web 13 a forming the joint groove 24 a is pivotally supported by the right end portion of the strut 23 with a pivot pin 25. The free end 24c on the left half side of both plates positioned in the middle part of the strut 23 can be inserted with a cable end 27a main body fixed to an end of an inner cable 27 constituting a brake cable 26 described later. Thus, a gap 24d is formed so as to be separated from each other, and semi-arc-shaped grooves 24e and 24e that can connect both ear portions 27b and 27b of the cable end 27a are formed on the opposite side of the brake cable 26 in the pulling direction.
[0008]
The struts 23 and the brake lever 24 constituting the crank mechanism 22 have their outer end surfaces (sliding contact surfaces) 23f and 24f on the brake cable 26 pulling direction side on the heads of the mounting bolts 20 and 21, respectively. It is slidably mounted. The outer end surface 23f of the strut 23 is formed in a flat surface so as to translate on the head of the left mounting bolt 20, and the outer end surface 24f of the brake lever 24 is the head of the right mounting bolt 21. An arcuate surface is formed so as to translate while rotating about the shaft pivot pin 25 on the part.
[0009]
The brake cable 26, which is a remote force transmission member, includes an inner cable 27, an outer casing 28, and the like. One end portion on the drum brake device side is arranged in a direction parallel to the brake shaft direction, and passes through an intermediate portion arranged along a chassis not shown in the drawing, and the outer casing 28 that protects the inner cable 27 from the outside air. The other end is fixed to the chassis, and the other end of the inner cable 27 that is slidably fitted into the chassis is fixed to an operation lever in the vehicle compartment.
[0010]
Thus, one end of the brake cable 26 is arranged as follows. One end of a guide pipe 29 is fixed to the seat portion 16b of the anchor block 16, and the other end portion extends vertically through the back plate 11 and the stationary portion 10 of the vehicle body (in a direction parallel to the brake shaft direction). Yes. Then, one end portion of the outer casing 28 is fixed to the outer end portion of the guide pipe 29, and one end portion of the inner cable 27 extending through the guide pipe 29 has a substantially cross shape fixed to the end portion. Both ear portions 27b and 27b of the cable end 27a are connected to the semicircular arc grooves 24e and 24e of the brake lever 24. Accordingly, when the inner cable 27 is pulled, the brake lever 24 is viewed in a direction crossing the brake shaft, in other words, the free end portion 24c is strutted when viewed from the direction orthogonal to the brake shaft ( shown in FIG. 9 ) . This is a structure that rotates along an arcuate locus centering on the axis of a pivot pin 25 that is a pivotal support portion with respect to the shaft 23. The “arc-shaped trajectory” expressed above captures a certain point of the free end 24c. However, if the free end 24c is captured by a surface, it has a structure that rotates so as to draw a fan-shaped surface.
[0011]
Next, the brake operation in the above-described configuration will be described. Now, when the free end portion 24c of the brake lever 24 is pulled through the inner cable 27, the brake lever 24 rotates counterclockwise in FIG. 9 with the pivot pin 25 as a fulcrum, and the right brake shoe 13 is expanded. Then, it is frictionally engaged with a brake drum (not shown). At the same time, the reaction force acts on the strut 23 via the pivot pin 25, thereby expanding the left brake shoe 12 and frictionally engaging the brake drum. Thus, the frictional force of the primary brake shoe 12 or 13 with respect to the rotation direction of the brake drum is transmitted to the secondary brake shoe 13 or 12 via the adjuster 17, and this is supported by the anchor block 16 and applied to the braking force. It acts as a duo-servo type drum brake device.
[0012]
[Problems to be solved by the invention]
The crank mechanism at the time of the brake operation described above is a state in which both the brake shoes and the brake shoes are in a state where either brake shoe is supported on the anchor block and generates a braking force from the time when both brake shoes are frictionally engaged with the brake drum. Rotates integrally with the brake drum. At this time, due to the traction force of the inner cable, the acting force in the back plate direction applied to the crank mechanism in which the strut and the brake lever are integrated is supported by the frictional force of the contact portion between the strut and the brake lever and the brake shoe. Therefore, the crank mechanism slides in a state where the crank mechanism is strongly pressed on the head of the mounting bolt, and moves in parallel.
[0013]
If the conventional crank mechanism is tilted in the brake radial direction as much as possible, the contact of the mounting bolt with the head becomes point contact or line contact, resulting in a very large surface pressure. In particular, in the brake lever, the contact with the line contact is originally a point contact, and the outer end surface of the brake lever rotates in a direction against the sliding direction, that is, the outer end surface of the brake lever rotates in a direction not rolling. It moves parallel. Therefore, when the brake shoe begins to frictionally engage with the brake drum and the crank mechanism rotates slightly with the brake drum or the like about the brake shaft center to translate on the head of the mounting bolt, the sliding contact occurs. It is in a state of being scratched by a sharp edge portion in the plate thickness direction of the portion. Due to repeated braking operation under such conditions, local wear of the head of the mounting bolt is likely to be promoted, and the smooth sliding over the long term of the crank mechanism is hindered, resulting in a problem that the braking performance is lowered. It was. In addition, when the head of the mounting bolt is rough, an abnormal noise (sliding noise or scratching noise) is generated, which may cause discomfort to the passenger.
[0014]
In order to solve the above-mentioned problems, conventionally, grease has been applied to the head of the mounting bolt, or a relatively hard surface treatment such as hard chrome plating has been applied to the mounting bolt. The effect on the sharp edges of the crank mechanism was poor. In particular, the structure in which the crank mechanism slides on the back plate is generally treated by applying grease as a solution, but it is used together with anti-corrosion paint on the back plate and wear powder from friction materials on the brake shoes. Since the grease dropped, the application work was often forced and troublesome.
[0015]
It is an object of the present invention to obtain a drum brake device that is durable even without repeated wear of the head of the mounting bolt and that can provide stable braking performance over a long period of time. . It is another object of the present invention to provide a drum brake device that does not cause an unpleasant sensation by generating abnormal noise.
[0016]
[Means for Solving the Problems]
In order to achieve the above-described object, in the drum brake device according to the present invention, a movable shim is interposed between the sliding portion of the crank mechanism which is the shoe expansion device and the stationary member.
[0017]
The crank mechanism described above includes a brake lever, a strut, and the like. When the free end of the brake lever is pulled by a remote force transmission member, the free end of the brake lever is pivoted with respect to the strut when viewed in a direction crossing the brake shaft. It is of a type that rotates along an arcuate trajectory centered on a branch.
[0018]
And with the strut operatively engaging one end to one of the brake shoes is accommodated in a gap formed over the other end from the intermediate portion of the strut, the intermediate portion of the strut A remote force transmission member is connected to the free end portion that is positioned, and a brake lever that operatively engages the other brake shoe in the vicinity of the base portion that is located on the other end side of the strut, and the base portion of the brake lever and the strut A crank mechanism of a type constituted by a pivot pin that pivotally supports the other end of the shaft can be applied .
[0019]
Further, the shim interposed between the sliding portion and the stationary member of the crank mechanism may be provided only in the sliding contact portion that slides in the harshest state, or may be provided in all the sliding contact portions. Moreover, you may provide in both a crank mechanism and a stationary member.
[0020]
The shim may be formed by a leaf spring. Further, grease may be applied to the sliding portion of the shim.
[0021]
According to the drum brake device configured as described above, when the crank mechanism moves in parallel with the stationary member under a state where the crank mechanism is strongly pressed in the direction of the stationary member, for example, the crank mechanism is tilted. Even if it is difficult to slide, the shim interposed between the sliding portion and the stationary member moves integrally with the crank mechanism, and the shim can easily slide on the stationary member. Further, since the slidable sliding contact portions are on both sides of the shim, the smooth sliding of the crank mechanism can be ensured also from this point. Therefore, especially the local wear of the stationary member can be reduced and the crank mechanism always slides smoothly, so that stable braking performance can be maintained over a long period of time, and the rough surface of the sliding surface is eliminated. Generation of abnormal noise can be suppressed.
[0022]
Note that the crank mechanism consisting of a brake lever, strut, etc., when the free end of the brake lever is pulled by the remote force transmission member, the free end of the brake lever is a pivotal support with the strut when viewed in the direction crossing the brake shaft. Rotating along an arcuate trajectory centered on the strut, specifically, a strut operatively engaging one end with one brake shoe and formed from the middle to the other end of the strut The remote force transmission member is connected to the free end located on the intermediate portion side of the strut, and the vicinity of the base located on the other end side of the strut is connected to the other brake shoe. brake lever operatively engaged and may be a composed format from the pivotally supported pin pivotally supporting the other end portion of the base and the strut of the brake lever, moreover click Stationary member for mounting the link mechanism from good in mounting bolts and the back plate or the like of the anchor block, its application range is broad and applicable to various types of drum brake devices.
[0023]
In addition, if the shim interposed between the sliding portion of the crank mechanism and the stationary member is provided only in the sliding contact portion that slides in the harshest state, the durability as a whole is improved. If it is provided on the moving part or on both the sliding part and the stationary member of the crank mechanism, the durability can be further improved.
[0024]
In addition, if the shim is formed from a leaf spring, it can be easily formed in one piece by pressing, so that the processing is simple and suitable for mass production, and because it is hard due to heat treatment, it is a component that requires durability. It is suitable as. Furthermore, if grease is applied to the sliding portion of the shim, the friction coefficient can be reduced, and a smoother parallel movement of the crank mechanism with respect to the stationary member can be ensured.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a drum brake device according to the present invention will be described. In the description, the first to fourth embodiments are the same as the conventional example described above except for the structure around the mounting portion on the stationary member of the crank mechanism, and the same parts and portions are denoted by the same reference numerals. A description of the structure and brake operation is omitted.
[0026]
First, FIG. 1 showing a longitudinal section of the crank mechanism 22 part and a diagram showing a single shim 30 regarding the first embodiment of the present invention related to the brake lever 24 side that slides in a harsh state in the crank mechanism 22 of the conventional example. This will be described with reference to FIG. However, in order to simplify the drawing, FIG. 1 also shows a structure on the strut 23 side according to a third embodiment of the present invention which will be described later. The shims of the present invention described below are all made of leaf springs.
[0027]
Thus, the structure of this example will be described focusing on the differences from the structure of the conventional example described above. The shim 30 has a U-shape as a whole, and the head of the mounting bolt 21 whose opposing piece is a stationary member. It is installed in a fashion that sandwiches the upper and lower surfaces. More specifically, as shown in FIG. 2, the shim 30 has a notch 30 b that fits into one of the stationary pieces 30 a of the opposed pieces and a shaft portion of the mounting bolt 21 from one side in the width direction. The other movable piece 30c is formed with an engaging claw 30d on the free end side thereof for contact with the outer periphery of the head of the mounting bolt 21 for positioning.係 合, this engaging claw 30d is not an essential element.
[0028]
As shown in FIG. 1, the shim 30 is fixedly sandwiched between the stationary piece 30a between the head of the mounting bolt 21 and the seat portion 16b of the anchor block 16, and the movable piece 30c is fixed to the mounting bolt. 21 is mounted on the head of the head 21 with a light contact surface, and the outer end surface 24f of the brake lever 24 is placed on the movable piece 30c. Note that when the stationary piece 30a of the shim 30 is sandwiched, if the curved portion 30e that connects the stationary piece 30a and the movable piece 30c is disposed on the return direction side of the brake lever 24, the movable piece 30c is This is desirable because when the brake lever 24 is displaced in the operating direction, it tends to elastically deform in a direction approaching the stationary piece 30a.
[0029]
In the above-described configuration, when the brake shoes 12 and 13 start to frictionally engage with the brake drum during the brake operation, the pressing force acting on the movable piece 30c of the shim 30 from the outer end surface 24f of the brake lever 24 increases rapidly. While the outer end surface 24f rotates, the movable piece 30c is pushed to displace the bending portion 30e while elastically deforming. Accordingly, since the rotation direction of the outer end surface 24f of the brake lever 24 and the displacement direction of the movable piece 30c of the shim 30 are substantially the same direction, the outer end surface 24f of the brake lever 24 can be translated while being rolled. It is clear.
[0030]
Thus, even when the outer end surface 24f of the brake lever 24 is in point contact with the crank mechanism 22 tilted, the movable piece 30c of the shim 30 is in surface contact with the head of the mounting bolt 21. In particular, the local wear on the head of the mounting bolt 21 can be reduced, stable braking performance can be maintained over a long period of time, and the occurrence of abnormal noise can also be suppressed. Further, when the brake is released, the elastic force accumulated with the elastic deformation of the curved portion 30e of the shim 30 also works as the return force of the brake lever 24, which is convenient. In addition, if the shim 30 is formed by a leaf spring, it can be easily integrally formed by pressing, so that the processing is simple and suitable for mass production, and since it is hard by heat treatment, it has excellent durability. Furthermore, if grease is applied on the head of the mounting bolt 21, smoother sliding of the movable piece 30c of the shim 30 can be ensured.
[0031]
Next, a modified example of the shim will be described with reference to FIGS. 3 and 4, but the description of the operation and effect will be omitted because it is equivalent to that of the first embodiment described above. In the shim 31 of this example, curved portions 31b and 31b and latching portions 31c and 31c are formed at both ends of a rectangular movable portion 31a, respectively. The curved portion 31b and the latching portion 31c are generally S. It has a letter shape and an inverted S-shape and is opposed to each other. The movable portion 31a is fitted into a groove 21a formed on the head of the mounting bolt 21 so as to be slidable substantially only in the moving direction of the brake lever 24, and the latching portions 31c and 31c are formed on the anchor block 16. The parallel surfaces 16c and 16c and the lower surface of the head of the mounting bolt 21 are elastically engaged and mounted. Note that the mounting structure of the shim 31 is not limited to this. For example, the thickness of the head of the mounting bolt 21 is increased, and the parallel surface 16c, 16c of the anchor block 16 is provided on the outer periphery on the lower surface side. The surface can be integrally molded and mounted here, or the parallel surfaces 16c, 16c described above can be replaced with U-shaped or U-shaped depressions, and the latching portions 31c, 31c of the shim 31 can be placed in these depressions. Since the rotation can be restricted by mounting the, the groove 21a formed in the mounting bolt 21 can be omitted.
[0032]
Next, a second embodiment of the present invention will be described with reference to FIGS. However, in order to simplify the drawing, FIG. 5 also shows a structure on the strut 23 side according to a fourth embodiment of the present invention to be described later. The shim 32 of this example has a generally ship shape, and an intermediate portion thereof is formed on an arc surface 32a along the outer end surface 24f of the brake lever 24, and both plate surfaces of the brake lever 24 are lightly sandwiched between both side surfaces thereof. The sandwiching portions 32b and 32b are bent. Further, a latching portion 32c bent in an inverted S shape is formed at the left end of the arcuate surface 32a in FIG. 5, and this latching portion 32c surrounds the protrusion 24g formed on the brake lever 24. On the other hand, a bent curved portion 32d is formed at the right end, and this curved portion 32d is elastically engaged with the protruding end of the brake lever 24, and a predetermined gap is formed between the protruding end surface. There is a gap. In other words, the arc surface 32 a of the shim 32 can be relatively displaced along the outer end surface 24 f of the brake lever 24.
[0033]
When the brake is actuated in the above-described configuration, the brake lever 24 and the shim 32 are always rotated together to move in parallel on the head of the mounting bolt 21. Therefore, the smooth outer surface of the shim 32 comes into sliding contact with the head of the mounting bolt 21 and is not damaged. Further, even if the friction coefficient on the head of the mounting bolt 21 increases, the outer end surface 24f of the brake lever 24 can relatively move on the inner surface of the high hardness shim 32 against the elastic force of the curved portion 32d. And excellent durability. In the present embodiment, the grease may be applied only on the head of the mounting bolt 21, but preferably it may be applied also to the inner surface of the arc surface 32 a of the shim 32.
[0034]
Next, Embodiments 3 and 4 of the present invention in which shims are mounted on the strut 23 side will be described. First, the third embodiment will be described with reference to FIG. 1. In this example, the shim 30 or 31 of the first embodiment described above is applied. In this figure, an application example of the shim 30 is illustrated. is there. Thus, the effects of the shim 30 or 31 in this example are the same as those in the first embodiment, and the description thereof is omitted.
[0035]
Next, Embodiment 4 will be described with reference to FIG. The shim 33 of the present example has a shape along the outer peripheral surface of the protrusion on the mounting bolt 20 side that forms the shoe engagement groove 23e from the groove bottom of the shoe engagement groove 23e of the strut 23 as a whole. The curved portion 33a facing the front end surface of the protrusion has a predetermined gap. In addition, sandwiching portions 33b and 33c are formed on both sides of the portion of the shoe engaging groove 23e that slides on the head of the mounting bolt 20 to prevent displacement by sandwiching both plate surfaces of the strut 23. ing. Accordingly, the effects of the shim 33 in this example are substantially the same as those of the second embodiment described above, and a description thereof will be omitted.
[0036]
Although the brake levers 24 of the first to fourth embodiments described above are each composed of a combined body in which two plates are stacked and integrated, the present invention is not limited to this. For example, it is possible to apply a brake lever composed of a single plate as shown in FIG. 7, and the cable ends are different accordingly. Accordingly, only the brake lever 24 and the cable end 27a shown in the first to fourth embodiments will be described with reference to FIG.
[0037]
That is, since the brake lever 44 is composed of a single plate body, the cable end 47a fixed to the end portion of the inner cable 47 has a hollow rectangular frame, and this hollow portion is formed by the free end portion 44c of the brake lever 44. It is the structure inserted and connected to the semicircular arc-shaped groove 44e. Although not shown in the drawing, as in the first to fourth embodiments described above, it is clear that an equivalent effect can be obtained if a shim is interposed between the sliding portion of the crank mechanism and the non-moving member. To do.
[0038]
Incidentally, the shim 30 to 3 3 according to the present invention described above, although lists examples mounted on one of the crank mechanism 22 and the stationary member 20, 2 1, the above-described effects when mounted on both remarkably improved It is clear. Although an example of a duo-servo type drum brake device has been described, the present invention is not limited to this. For example, the brake shoes 12 and 13 are supported in the same manner as the anchor block 16 instead of the adjuster 17 in the conventional example. A so-called leading trailing drum brake in which an anchor member having a function and, in addition to this, a function of adjusting a gap between the brake shoes 12 and 13 and a brake drum (not shown) is disposed and fixed on the back plate 11. In this case, the crank mechanism 22 is placed on the back plate 11 via a shim.
[0039]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained. In other words, since a movable shim is interposed between the crank mechanism that extends the brake shoe and the stationary member to slide, the crank mechanism is strongly pressed in the direction of the stationary member when the brake is operated, and the edge is sharp. Even if the shim moves parallel to the stationary member under the contact state, the shim moves integrally with the crank mechanism, and the smooth surface of the shim slides on the stationary member. Further, since the slidable sliding contact portions are on both sides of the shim, the smooth sliding of the crank mechanism can be ensured also from this point. Therefore, since the local wear of the stationary member can be reduced and the crank mechanism always slides smoothly, stable braking performance can be maintained over a long period of time, and severe roughening of the sliding surface can be eliminated. The generation of abnormal noise can be suppressed.
[0040]
In addition, when the free end of the brake lever is pulled by a remote force transmission member, the crank mechanism consisting of a brake lever, strut, etc., is viewed in the direction crossing the brake shaft. Rotating along an arcuate trajectory centered on the strut, specifically, a strut operatively engaging one end with one brake shoe and formed from the middle to the other end of the strut The remote force transmission member is connected to the free end located on the intermediate portion side of the strut, and the vicinity of the base located on the other end side of the strut is connected to the other brake shoe. brake lever operatively engaged and may be a composed format from the pivotally supported pin pivotally supporting the other end portion of the base and the strut of the brake lever, moreover Kura Stationary member for mounting the click mechanism may be a mounting bolt or the back plate, etc. of the anchor block, further, its application range is broad and can be applied to a drum brake device, such as a duo-servo type or leading trailing form.
[0041]
In addition, the shim interposed between the sliding portion and the stationary member of the crank mechanism can improve the overall durability even if it is provided only in the sliding contact portion that slides in the harshest state. If it is provided on the sliding part or on both the sliding part and the stationary member of the crank mechanism, the durability can be further improved.
[0042]
In addition, if the shim is formed of a leaf spring, it can be easily integrally formed by pressing, so that the processing is simple and suitable for mass production. It is suitable as a required part.
[0043]
Furthermore, if grease is applied to the sliding portion of the shim, the friction coefficient can be reduced, and a smoother parallel movement of the crank mechanism with respect to the stationary member can be ensured.
[Brief description of the drawings]
1 is a cross-sectional view of a crank mechanism according to first and third embodiments of the present invention. FIG. 2 is a perspective view showing a shim of FIG. 1. FIG. 3 is a cross-sectional view of an essential part showing a modification of the first and third embodiments. 3 is a perspective view of the shim of FIG. 3. FIG. 5 is a cross-sectional view of the crank mechanism portion according to the second and fourth embodiments of the present invention. FIG. 6 is a perspective view of the shim of the second embodiment. 1 to 4 show a modification of the brake lever, wherein (A) is a plan view of the cable end connected to it (B) is a side view of the cable end (C) is a cross-sectional view taken along line CC of (B).
FIG. 8 is a plan view of a drum brake on which the present invention is based.
[9] IX-IX cross-sectional view of FIG. 8
10 is a sectional view taken along line XX in FIG . 9 ;
DESCRIPTION OF SYMBOLS 10 Car body stationary part 11 Back plate 12, 13 Brake shoe 16 Anchor block 17 Adjuster 20, 21 Mounting bolt 22 Crank mechanism 23 Strut 24 Brake lever 25 Pivot pin 26 Brake cable 27 Inner cable 28 Outer casing 29 Guide pipes 30-33 Shim 44 brake lever

Claims (5)

A strut operatively engage an end portion on one of the brake shoes is accommodated in a gap formed over the other end from the intermediate portion of the strut, located in the middle portion of the strut A remote force transmission member is connected to the free end, and a brake lever that operatively engages the other brake shoe in the vicinity of the base located on the other end of the strut, and the base of the brake lever and the strut crank mechanism and a pivotally supported pin Ru formed to pivotally support the other end of the are arranged, when pulling the remote force transmission member connected to the free end of the brake lever, as viewed in a direction transverse to the brake shaft, said A drum brake device in which a free end portion of a brake lever rotates along an arcuate locus centering on a pivotal support portion with a strut, and the crank mechanism slides on a stationary member to operate a brake. In,
A shim is movably interposed between the sliding portion of the crank mechanism and the stationary member , and both the brake lever and the strut are placed on the stationary member with the shim interposed therebetween, Drum brake device. Oite to claim 1, said shim, characterized in that mounted on at least one of said brake lever and said stationary member, a drum brake device. Oite to claim 1, said shim, characterized in that mounted on at least one of said stationary member and the strut, a drum brake device. The drum brake device according to any one of claims 1 to 3 , wherein the shim is a leaf spring. The drum brake device according to any one of claims 1 to 4 , wherein grease is applied to a sliding portion of the shim.

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