JPH11182593A - Duo-servo type drum braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take a countermeasures against abnormal noise generated when a brake shoe is brought into contact with an anchor pin so that no brake components are affected. SOLUTION: A cylindrical member 21 formed of a spring steel plate is fitted to an anchor pin 7, and the inside diameter of the cylindrical member 21 is determined so that a clearance δ is present therebetween. When a brake operating force is released from the braked condition, brake shoes 3, 4 hold the cylindrical member 21 by the spring force of a shoe return spring to elastically deform the cylindrical member in the diameter direction by the clearance δ. The elastic deformation of the cylindrical member 21 plays the buffer function when the brake shoes 3, 4 are brought into contact with the anchor pin 7, and prevents generation of abnormal noise during the contact. The cylindrical member 21 need not be fitted to brake components so as to fit the cylindrical member 21 to the anchor pin 7, and influence on the brake components can be completely eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a duo servo type drum brake device used as a rear brake or a center brake (also referred to as a transmission brake) of an automobile, and more particularly to a brake shoe which comes into contact with an anchor pin when a brake is released. The present invention relates to a technique for suppressing generated abnormal noise.

[0002]

2. Description of the Related Art Conventionally, as a technique for suppressing abnormal noise generated when a brake shoe comes into contact with an anchor pin when a brake of a duo-servo type drum brake device is released, for example, Japanese Utility Model Publication No. 5-27712, Japanese Utility Model Application Laid-Open No. 6-
As described in Japanese Patent No. 73474, it has been proposed to attach a buffer member made of a spring plate or the like to a brake shoe to take measures against abnormal noise.

According to the conventional measures, when the brake shoe comes into contact with the anchor pin at the time of release of the brake, this contact is performed via the above-mentioned cushioning member. Abnormal noise at the time of contact with the pin can be suppressed.

[0004]

However, in the conventional measures, since the cushioning member is mounted on the brake shoe, the mounting structure for that purpose is complicated, large, and the cost is high. In addition to being large in size, it is inevitable that it will be disadvantageous in terms of cost.

[0005] Further, when the cushioning member is attached to the brake shoe, there is a concern that the cushioning member may be deformed or damaged during the handling of the brake shoe, and there is a problem that the handling of the brake shoe becomes troublesome. Furthermore, when the brake lining of the brake shoe becomes worn and the service limit is reached, the brake lining is replaced and reused.However, the buffer member must be removed and attached every time the brake lining is replaced. The problem is that the quality is greatly reduced and there is a fear that the product may be out of stock.

A first aspect of the present invention is a duo capable of suppressing abnormal noise generated when a brake shoe comes into contact with an anchor pin when a brake is released, without causing the above-described problems. An object of the present invention is to propose a servo-type drum brake device.

According to a second aspect of the present invention, the first aspect is simply the first aspect.
An object of the present invention is to propose a duo-servo type drum brake device that can achieve the object of the invention.

A third aspect of the present invention aims to propose a duo-servo type drum brake device which can realize the second aspect at the lowest cost.

A fourth aspect of the present invention has an object to propose a duo-servo type drum brake device in which the second aspect of the invention is embodied by another configuration.

A fifth aspect of the present invention has an object to propose a duo-servo type drum brake device in which the second aspect of the invention is embodied by a further different configuration.

A sixth aspect of the present invention is to provide a duo-servo type drum brake device which can more reliably achieve the object of the present invention in the second to fifth aspects. .

A seventh aspect of the present invention is directed to another proposal for making it possible to more reliably achieve the object of the present invention in the second to sixth aspects.

An eighth object of the present invention is to propose a duo-servo type drum brake device which can easily achieve the object of the first invention by selecting a material.

A ninth aspect of the present invention is to propose a particularly useful countermeasure against abnormal noise in a single anchor type duo servo type drum brake device.

A tenth aspect of the present invention is directed to propose a particularly useful countermeasure against abnormal noise in a double anchor type duo servo type drum brake device.

An eleventh aspect of the present invention is to propose a duo-servo type drum brake device in which the noise suppression member also has a function of preventing the lifting of the brake shoe, thereby suppressing an increase in cost. .

[0017]

SUMMARY OF THE INVENTION To achieve these objects, a first aspect of the invention is to provide a brake shoe having a pair of brake shoes so that one adjacent end is in elastic contact with a fixed anchor pin, and the other adjacent end is An inner peripheral surface of a brake drum, which is provided so as to be in contact with both ends of a link connecting the adjacent ends to each other so that the two brake shoes are expanded so that the one adjacent end is separated from the anchor pin. In a duo-servo type drum brake device in which both brake shoes connected by the link rotate integrally and perform a braking action by contact with an anchor pin, a tubular member is fitted to the anchor pin, The brake shoe is configured to receive the one adjacent end of each of the brake shoes under cushioning via a cylindrical member.

According to a second aspect of the present invention, there is provided a duo-servo type drum brake device according to the first aspect, wherein
A gap is set between the cylindrical member and the fitted cylindrical member, and the buffer is generated by elastically deforming the cylindrical member by the gap.

According to a third aspect of the present invention, in the duo-servo type drum brake device according to the second aspect, the cylindrical member has a cylindrical shape whose inner diameter is larger than the outer diameter of the anchor pin, and the gap is set between the two. It is characterized by the following.

According to a fourth aspect of the present invention, there is provided a duo-servo type drum brake device according to the second aspect, wherein the cylindrical member is formed into a barrel shape, and the gap is set between the cylindrical member and the anchor pin. It is assumed that.

According to a fifth aspect of the present invention, there is provided a duo-servo type drum brake device according to the second aspect, wherein the cylindrical member is formed into a drum shape, and the gap is set between the cylindrical member and the anchor pin. It is assumed that.

In a duo-servo type drum brake device according to a sixth aspect of the present invention, in any one of the second to fifth aspects, the cylindrical member is formed by rolling a plate material, but is opposed by the rolling. A cylindrical member in which a slit remains between both ends of the plate material.

According to a seventh aspect of the present invention, there is provided a duo-servo type drum brake device according to any one of the second to sixth aspects, wherein the tubular member is made of a spring steel plate.

According to an eighth aspect of the present invention, there is provided a duo-servo type drum brake device according to the first aspect, wherein the cylindrical member is made of a damping steel plate, and the damping is performed according to the material characteristics of the damping steel plate. Is what you do.

A ninth aspect of the present invention is a duo-servo type drum brake device according to any one of the first to eighth aspects, wherein when the anchor pin is a single anchor pin common to both brake shoes, the cylindrical member is formed of a double anchor. The buffering is performed by being diametrically pressed between the corresponding adjacent ends of the brake shoes.

According to a tenth aspect of the present invention, there is provided a duo-servo type drum brake device according to any one of the first, second, fourth, fifth, sixth, seventh and eighth inventions. Where is a double anchor pin individually installed for both brake shoes, the tubular member is configured to be clamped between the anchor pin and the corresponding end of the brake shoe to perform the buffering. Is what you do.

An eleventh aspect of the present invention is the duo-servo type drum brake device according to any one of the first to tenth aspects, wherein the one adjacent end of the brake shoe has an axial line with respect to an anchor pin at the tip of the tubular member. The shoe guide plate is formed integrally with the shoe guide plate to prevent the shoe guide plate from coming off in the direction.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1 and 2 show a duo-servo type drum brake device according to an embodiment of the present invention. In this embodiment, the drum brake device has a service brake function and a parking brake function, and Use a configuration that is useful as a brake.

First, the overall structure of the drum brake device will be described with reference to FIG. Reference numeral 1 denotes a fixed back plate attached to a vehicle body (not shown). The back plate 1 is an axial opening end of a brake drum 2 (only a peripheral wall portion is indicated by a two-dot chain line in FIG. 1) which rotates together with wheels. The space (on the other side of FIG. 1) is closed to define a space between the brake drum 2 and a brake component as described below.

That is, as shown in FIG. 1, a pair of brake shoes 3 and 4 are provided so as to face the inner peripheral surface of the brake drum 2 and these brake shoes 3 and 4 are respectively provided with a brake shoe holding mechanism 5. , 6 to support the back plate 1 so that it can be displaced within the limited range. The brake shoes 3 and 4 are respectively composed of rims 3a and 4a extending along the brake drum 2, webs 3b and 4b fixed to the back surface thereof, and linings 3c and 4c attached to the front surfaces of the rims 3a and 4a. Constitute.

The brake shoes 3 and 4 have one adjacent ends (specifically, the adjacent ends of the shoe webs 3b and 4b) positioned above in FIG. The common fixed anchor pin 7 thus planted is brought into contact with the cylindrical portion 7a, and the other adjacent ends are brought into contact with both ends of the shoe gap adjusting adjuster 8, respectively, so as to face each other. In order to prevent the ends of the brake shoes 3, 4 in contact with the anchor pin 7 from floating in the axial direction of the anchor pin 7, a shoe guide plate 9 is engaged with the anchor pin 7. As shown in FIG. 2, the anchor pin is seated on the distal end surface of the cylindrical portion 7a.

As shown in FIG. 1, upper shoe return springs 10 and 11 are stretched between the tip of the anchor pin 7 and the brake shoes 3 and 4, respectively. The corresponding adjacent ends of the shoes 3 and 4 are elastically brought into contact with the anchor pin 7.

A lower shoe return spring 12 is stretched between the other adjacent ends of the brake shoes 3 and 4 so that the other adjacent ends abut on both ends of the shoe gap adjuster 8, respectively. Keep it. Here, the shoe gap adjuster 8 is of a non-rotating type with a bolt member 8b rotatably applied to the brake shoe 3 (specifically, shoe web 3b) via a socket member 8a, and a brake shoe 4 (specifically, shoe web 4b). And a bolt member 8b and a nut member 8c are screwed together. On the outer periphery of the bolt member 8b, an adjusting tooth wheel 8d is provided.
The adjusting tooth wheel 8d is rotated by a tool, and a screw action between the bolt member 8b and the nut member 8c causes the brake drum 2 and the brake shoes 3,
4 can be adjusted.

The shoe gap adjuster 8 serves as a link for interconnecting the corresponding adjacent ends of the brake shoes 3 and 4 together with the spring force of the lower shoe return spring 12.

In the vicinity of the anchor pin 7, between the brake shoes 3 and 4, a wheel cylinder 13 for expanding the brake shoes in a direction away from each other is interposed, and as shown in FIG. Attach to The wheel cylinder 13 has pistons 13a at both ends.
13b, which are slidably fitted to each other.
a, a brake fluid pressure chamber 13c is provided between 13a and 13b,
When the brake fluid pressure generated by the service brake is supplied to this chamber from the port 13d (see FIG. 2), the pistons 13a and 13b are pushed out and the push rod 1
It is assumed that a service brake can be obtained through the buttons 4 and 15 as described later.

Here, the push rods 14 and 15 are directly linked to the corresponding brake shoes 3 and 4, respectively.

Next, the parking brake operating mechanism will be described. This parking brake operating mechanism has a parking brake operating lever 16 which is arranged on the side of the brake shoe 4. The base end 16a of the parking brake operation lever 16 is pivotally supported by the pin 17 on the end of the brake shoe 4 near the anchor pin 7, and is shifted from the base end 16a of the parking brake operation lever 16 toward the operation end 16b. A strut 18 is installed between the point 16c and the point 3d of the brake shoe 3 near the push rod 14.

The strut 18 is provided with an anti-rattle spring 19 wound therearound, whereby the strut 18 is urged toward the parking brake operation lever 16 to prevent vibration. In addition, it is a matter of course that a gap is set between the strut 18 and the brake shoe 4 so that the strut 18 does not interfere with the brake shoe 4.

One end of a brake cable 20 is connected to the operation end 16b of the parking brake operation lever 16, and the other end of the brake cable 20 is connected to a parking brake lever (not shown) in the driver's seat. Here, when the driver operates the above-mentioned parking brake lever for parking and stopping, the operation force indicated by W in FIG. 1 is transmitted to the brake cable 20, which reaches the operation end 16 b of the parking brake operation lever 16. And

In this embodiment, in particular, as shown in FIG. 2, the tubular member 21 is fitted to the cylindrical portion 7a of the anchor pin 7 with which the brake shoes 3 and 4 abut. This tubular member 21 is preferably made of a spring steel plate, and has a small gap δ as shown in FIG.
The inner diameter is set so that

The operation of the duo-servo type drum brake device according to the above embodiment will be described below. In the non-braking state shown in FIG. 1, when the brake fluid pressure is supplied to the chamber 13c of the wheel cylinder 13 by the service brake, the two brake shoes 3, 4 move away from each other around the contact point with the shoe gap adjuster 8. It is expanded in such a direction and pressed against the inner peripheral surface of the brake drum 2. At this time, the brake shoes 3 and 4 are separated from the anchor pin 7 (specifically, the tubular member 21 fitted to the cylindrical portion 7a).

Now, the braking operation when the brake drum 2 receives a rotational force in the direction indicated by the arrow R from the wheels will be described. The brake shoes 3, 4, the shoe gap adjuster 8, and the parking brake operating lever 16 are integrated. As a result, the brake shoe 3 is rotated together with the brake drum 2 in the direction of arrow R, and the brake shoe 3 is displaced in the corresponding direction by a gap between the brake pin 2 and the anchor pin 7, and comes into contact with the brake shoe as shown in FIG. Due to this abutment, the above-mentioned integrally rotating brake components are no longer able to rotate, and stop at this position to generate a predetermined braking action on the brake drum 2.

When the brake drum 2 is receiving a rotational force in the direction opposite to the direction of the arrow R, the brake shoe 4 is displaced in the same direction by the gap between the brake shoe 4 and the anchor pin 7 and comes into contact therewith. A predetermined braking action is obtained in the same manner as described above.

When the parking brake operating force indicated by W in FIG. 1 is applied to the operating end 16b of the parking brake operating lever 16 by the parking brake, the lever 16 is rotated around the pin 17 in the counterclockwise direction in FIG. Then, the brake shoe 3 is expanded via the strut 18 so as to be separated from the anchor pin 7. As a result, when the brake shoe 3 comes into contact with the inner peripheral surface of the brake drum 2, the lever 1
Numeral 6 is also rotated counterclockwise around the contact point with the strut 18, and expands the brake shoe 4 via the pin 17 so as to separate from the anchor pin 7.

As a result, the two brake shoes 3 and 4 come into frictional contact with the inner peripheral surface of the brake drum 2, and thereafter a predetermined parking brake operation can be performed according to the same principle as in the service brake.

From the above braking state, the wheel cylinder 1
Next, the brake release operation when the brake is released by removing the brake fluid pressure in the third chamber 13c or removing the operation force W to the parking brake operation lever 16 will be described. At this time, of the brake shoes 3 and 4, the brake shoes separated from the cylindrical portion 7 a of the anchor pin 7 are the corresponding shoe return springs 10 and / or 11.
Thus, the brake shoe is returned to the non-braking position in FIG. 1 in contact with the cylindrical portion 7a of the anchor pin 7, and both brake shoes 3 and 4 are in the non-braking position. By the way, when the brake shoes 3 and 4 return and rotate, the two brake shoes 3 and 4 diametrically press the cylindrical member 21 fitted to the cylindrical portion 7a of the anchor pin 7 by the webs 3b and 4b. Is returned to the non-braking position in FIG. 1 while being elastically deformed in the same direction by the gap δ between the anchor pin cylindrical portion 7a shown in FIG. Accordingly, when the webs 3b, 4b of the brake shoes 3, 4 abut against the anchor pin cylindrical portion 7a, they come into abutment under cushioning through the elastic deformation of the tubular member 21 fitted to the cylindrical portion 7a. It is possible to prevent the webs 3b and 4b from directly abutting against the anchor pin cylindrical portion 7a to generate abnormal noise.

According to this countermeasure against abnormal noise, it is not necessary to attach the tubular member 21 to the brake shoes 3 and 4 for that purpose, and it is only necessary to fit the anchor pin cylindrical portion 7a when assembling the brake. The mounting structure of the shaped member 21 is unnecessary, and the structure of the brake shoes 3 and 4 does not become complicated or large.
The cost of the brake device does not increase.

Further, since the cylindrical member 21 can be handled as a single item without being preassembled with any other brake components, there is little possibility that the cylindrical member 21 will be deformed or damaged. The handling of brake components is not complicated. For example, when the brake linings 3c and 4c are worn out and the service limit is reached, the brake shoes 3 and 4 are replaced with the brake lining and reused. However, the workability of the brake lining replacement work is greatly reduced. Conventional problems can be avoided.

In order to prevent the brake linings 3c and 4c from being dragged by the inner peripheral surface of the brake drum 2 at the time of releasing the brake, the position between the cylindrical member 21 and the anchor pin cylindrical portion 7a is required at the time of releasing the brake. It is necessary to reduce the elasticity of the tubular member 21 so that the gap δ shown in FIG. 3 is completely eliminated. For this purpose the tubular member 21
As shown in FIG. 4, it is preferable to form the spring steel plate by a roll process, and to form a cylindrical member in which a slit 21a remains between both ends of the spring steel plate which is opposed by the roll process. In this case, the tubular member 21 is easily elastically deformed in the diameter direction due to the presence of the slit 21a, and the gap δ (see FIG. 3) between the tubular member 21 and the anchor pin cylindrical portion 7a when the brake is released is ensured. Can be elastically deformed in the diametric direction so as to completely disappear.

As shown in FIG. 5, the cylindrical member 21 is further provided integrally with a flange portion 21b extending radially outward from one end face, and the shoe guide plate 9 (see FIG. 1) is provided by the flange portion 21b. With this configuration, it is possible to prevent the brake shoes 3 and 4 from floating in the axial direction of the anchor pin 7. In this case, the shoe guide plate 9 is integrated with the tubular member 21, so that the handling of both is simplified, and the number of components is reduced, which is advantageous in cost.

In any of the above embodiments, the shoe webs 3b, 4
Although a cushioning function for preventing abnormal noise when b abuts on the anchor pin cylindrical portion 7a is generated, the cylindrical member 21 is formed of a damping steel plate having a structure in which a damping material is sandwiched, for example. However, the above-described cushioning function can be generated by the material characteristics of the damping steel sheet. In this case, a gap between the tubular member 21 and the anchor pin cylindrical portion 7a as shown by δ in FIG. 3 is unnecessary, and the tubular member 21 is fitted into the anchor pin cylindrical portion 7a without a gap. When the brake is released, the plate material of the tubular member 21 is moved to the shoe webs 3b, 4
When it is sandwiched between the anchor member b and the anchor pin cylindrical portion 7a, the above-described cushioning function is generated by the material characteristics of the damping steel plate forming the tubular member 21.

In FIGS. 1 to 3, the idea of the present invention is applied to a single anchor type duo servo type drum brake device in which only one anchor pin 7 is common to both brake shoes 3 and 4. The invention is not limited to this, and anchor pins are individually provided for both brake shoes,
The same concept can be applied to a so-called double anchor type duo servo type drum brake device.

FIGS. 6 and 7 show an application example of the present invention to a double anchor type duo servo type drum brake device. Reference numeral 31 denotes a fixed torque plate to be attached to a vehicle body (not shown). The torque plate 31 includes a brake drum 32 that rotates with the wheels (only the peripheral wall is shown by a two-dot chain line in FIG. 6 to show the brake components).
6 is closed in cooperation with the dust cover 33 to define a cavity between the brake drum 32 and the inside of the cavity, as described below. Install parts.

That is, as shown in FIG. 6, a pair of brake shoes 34 and 35 are provided so as to face the inner peripheral surface of the brake drum 32.
The rims 4 and 35 are composed of rims 34a and 35a extending along the inner peripheral surface of the brake drum 32, webs 34b and 35b fixed to the back surface thereof, and brake linings 34c and 35c attached to the front surface. Such a brake shoe 3
4 and 35 make the one adjacent end in the lower part of FIG. 6 abut against both ends of the shoe gap adjuster 36 which is floatingly supported, and make the shoe web 34b,
Inner peripheral surfaces of anchor holes 34d, 35d drilled in 35b;
Anchor pins 37, 38 implanted in torque plate 31
In cooperation with the cylindrical portions 37a and 38a.

Shoe return springs 39 and 40 are stretched between the brake shoes 34 and 35 and the anchor pins 37 and 38, respectively, and the brake shoes 34 and 35 are brought closer to each other by the tension of the shoe return springs 39 and 40. As a result, the inner peripheral surfaces of the anchor holes 34d and 35d are fixed to the cylindrical portions 37 of the fixed anchor pins 37 and 38, respectively.
a, 38a.

Further, the adjuster spring 41 is stretched between the adjacent ones of the brake shoes 34, 35, which are far from the anchor pins 37, 38, in a tensioned state.
These adjacent ends are respectively connected to the shoe gap adjusters 36.
By pressing the outer peripheral ring of the adjuster spring 41 against the adjusting tooth wheel 36a of the shoe gap adjuster 36, the adjusting screw integral with the adjusting tooth wheel 36a is blinded from the adjusting position. Prevent it from shifting.

Between the other adjacent ends of the brake shoes 34, 35 near the anchor pins 37, 38, a cam 42 for pushing the brake shoes 34, 35 in a direction away from each other is interposed. The cam portion 42b has a pair of cam surfaces 42a facing the end surfaces 34 and 35, and a cam drive shaft 42c protruding from one end surface of the cam portion 42b.

As shown in FIG. 6, the cam 42 is arranged such that the cam surfaces 42a of the cam portions 42b face the corresponding end surfaces of the brake shoes 34 and 35, respectively, and the cam drive shaft 42c is shown in FIG. As described above, it is rotatably supported by the bracket 43 connected to the torque plate 31.
The bracket 43 is fastened to the torque plate 31 together with the reinforcing stiffeners 44 by the anchor pins 37 and 38. Thus, the cam 42 can be rotationally driven by the cam drive shaft 42c, and is mounted so as to be swingable in the brake shoe expanding direction with the rotation support portion of the bracket 43 as a fulcrum.

As shown in FIG. 7, a brake operating lever 45 is engaged with the projecting outer end of the cam drive shaft 42c, and this is operated by a lever return spring 46 shown in FIG.
(2) is urged to rotate in the direction opposite to the brake operation direction F shown in FIG. The return rotation position of the brake operation lever 45 by the return spring 46 is limited to a non-braking position shown in FIGS. 6 and 7 by a fixed lever stopper 47 shown in FIG.

Next, a description will be given of a structure according to the gist of the present invention for preventing an anchor pin from hitting when the brake is released.
Also in the present embodiment, cylindrical members 48 and 49 are fitted to the cylindrical portions 37a and 38a of the anchor pins 37 and 38, respectively, and the shoe guide plate is attached to the anchor pins 37 and 38 so as to cover the cylindrical members 48 and 49, respectively. The brake shoes 34, 35 are engaged with the anchor pins 3
In addition to preventing the tubular members 48 and 49 from floating along the anchor pins 37 and 38, the floating members 7 and 38 are prevented from floating along the anchor pins 37 and 38.

In the present embodiment, the tubular members 48, 49 are fitted into the anchor pin cylindrical portions 37a, 38a without any gap, and these tubular members 48, 49 are fitted.
Is formed using the above-mentioned damping steel plate.

The operation of the duo-servo type drum brake device according to the above embodiment will be described below. In the non-braking state shown in FIGS. 6 and 7, when the brake operating force F shown in FIG. 6 is input to the operating end of the brake operating lever 45, the brake operating lever 45 is moved to the cam portion 4 via the cam drive shaft 42c.
2b, thus rotating clockwise the cam surface 42a about the center O ₁ of FIG.

As a result, the cam surfaces 42a respectively push the end faces of the corresponding brake shoes 34, 35 in a direction away from each other, and move the two brake shoes 34, 35 respectively around the contact point with the shoe gap adjuster 36. The brake linings 34 c and 35 c are pressed against the inner peripheral surface of the brake drum 32.

At this time, due to the widening of the brake shoes 34, 35, gaps are generated between the inner peripheral surfaces of the anchor holes 34d, 35d and the anchor pin cylindrical portions 37a, 38a, respectively. Here, when the brake drum 32 is rotated along with the wheels, the cam 42 expanding the brake shoes 34 and 35 swings in the brake shoe expanding direction about the bearing portion by the bracket 43 as described above. Therefore, depending on the rotation direction of the brake drum 32, the brake shoe 34 is attached to the anchor pin 37 or the brake shoe 3
The brake shoes 34, 35 and the like rotate integrally with the shoe gap adjuster 36 until the 5 abuts on the anchor pin 38. When the brake shoe 34 makes contact with the anchor pin 37 or when the brake shoe 35 makes contact with the anchor pin 38, the two brake shoes 34, 3
5 and the like cannot rotate integrally with the shoe gap adjuster 36, and the brake drum 32 can be braked as predetermined.

The operation when the braking force is released by removing the operation force F to the brake operation lever 45 from the above braking state will be described below. At this time, the brake shoes 34, 35 are returned by the respective shoe return springs 39, 40 to the non-braking positions of FIGS. 6 and 7 in contact with the corresponding anchor pin cylindrical portions 37a, 38a. When the brake shoes 34 and 35 return and rotate, both brake shoes 34 and 35 are attached to the anchor pin cylindrical portion 3.
Instead of directly contacting the anchor pins 7a and 38a, they contact the anchor pin cylindrical portions 37a and 38a via the cylindrical members 48 and 49 fitted to them.

At this time, the brake shoes 34, 35 are connected to the cylindrical members 48, 38 between the anchor pin cylindrical portions 37a, 38a.
Although the plate material of 49 is pinched, since the tubular members 48 and 49 are made of the damping steel plate as described above, the damping steel plate forming the tubular members 48 and 49 has a cushioning function due to the material characteristics during the pinching. It is possible to prevent the abnormal noise when the brake shoes 34, 35 abut against the anchor pin cylindrical portions 37a, 38a.

Even with such a countermeasure against abnormal noise, the cylindrical member 4
Since it is not necessary to attach 8, 49 to the brake shoes 34, 35 and only to fit the anchor pin cylindrical portions 37a, 38a when assembling the brake, the same operation and effect as in the above-described embodiment can be achieved. can do.

In this embodiment, it goes without saying that the shoe guide plates 50, 51 can be integrally formed at the tips of the tubular members 48, 49 in the same manner as described above with reference to FIG.

In the single anchor type duo servo type drum brake device shown in FIGS. 1 to 3, when the gap δ shown in FIG. 3 is set between the anchor pin 7 and the cylindrical member 21, Is set to be larger than the inner diameter of the anchor pin cylindrical portion 7a. Instead, as shown in FIG. 8, the tubular member 21 is barrel-shaped by the same method as described above with reference to FIG. 9 is formed into a cylindrical member made of a spring steel plate having a slit 21a, and the gap δ is set between the central portion in the axial direction of the cylindrical member 21 and the anchor pin cylindrical portion 7a, or FIG.
As shown in FIG. 4, the cylindrical member 21 is roll-formed into a drum shape in the same manner as described above with reference to FIG. 4 to form a cylindrical member made of a spring steel plate having a slit 21a. Even if the above-mentioned gap δ is set between the anchor pin cylindrical portion 7a, the same operation and effect can be achieved.

According to the cylindrical member 21 of FIG. 8 or FIG. 9 having such a configuration, it can be used as shown in FIG. 10 or FIG. 11 for the double anchor type duo servo type drum brake device shown in FIG. 6 and FIG. Thus, the effect of suppressing the hitting of the anchor pin can be achieved. That is, FIG.
As shown in FIG. 10 or 11, the cylindrical member 21 is fitted into the anchor pin cylindrical portions 37a, 38a, and as shown in FIG. 10, the axial center portion of the cylindrical member 21 and the anchor pin cylindrical portions 37a, 38a The gap δ is set between the two axial ends of the tubular member 21 and the anchor pin cylindrical portions 37a and 38a as shown in FIG.

In the double anchor type duo-servo type drum brake device, when the braking is released from the braking state, the brake shoes 34, 35 are moved by the respective shoe return springs 39, 40 to the corresponding anchor pin cylindrical portions 37a, 38a. To the non-braking position. When the brake shoes 34, 35 return and rotate, the brake shoes 34, 35 do not directly abut against the anchor pin cylindrical portions 37a, 38a, but allow the tubular member 21 fitted to them to have a gap δ. It is returned while being elastically deformed only.

Here, the above-mentioned elastic deformation of the tubular member 21 is caused by the brake shoes 34 and 35 being driven by the anchor pin cylindrical portion 37a,
When the brake shoes 34 and 35 abut against the anchor pin cylindrical portions 37a and 38a, an abnormal noise can be prevented. Even with such an abnormal noise countermeasure, the tubular member 21 is moved to the brake shoes
5, it is only necessary to fit to the anchor pin cylindrical portions 37a, 38a when assembling the brake, so that the same operation and effect as in the above-described embodiment can be achieved.

[0073]

Thus, in the duo-servo type drum brake device of the first invention, for example, the tubular member 21 (48, 49) is fitted to the anchor pin 7 (37, 38) with the above-described structure, and The corresponding adjacent ends of the two brake shoes 3, 4 (34, 35) are received by the anchor pins 7 (37, 38), respectively, under cushioning through the shaped members, so that the brake shoes and the anchor when the brake is released are released. Since it is configured to prevent the generation of abnormal noise due to the contact with the pin, it is not necessary to attach the tubular member 21 (48, 49) to the brake shoes 3, 4 (34, 35). Anchor pin 7 (37, 3
8), the cylindrical member 21 (48,
The mounting structure of 49) is unnecessary, and the structure of the brake shoes 3, 4 (34, 35) does not become complicated or large, and the cost of the brake device does not increase.

Further, since the cylindrical member 21 (48, 49) can be handled as a single item without being pre-assembled with any other brake components, there is little risk of deformation or damage. Also, handling of any other brake components is not complicated. For example, the brake shoes 3, 4 (34, 35) are brake linings 3c,
When 4c (34c, 35c) wears out and reaches the limit of use,
Although the brake lining is replaced and reused, a conventional problem that significantly reduces the workability of the brake lining replacement work can be avoided.

In the duo servo type drum brake device according to the second invention, a gap δ is set between the anchor pin 7 (37, 38) and the tubular member 21, and the cylindrical member 7 (37, 38) is elastically deformed to cause the above-mentioned buffering, so that the brake shoes 3, 4 (34, 35) and the anchor pins 7 (37, 38) when the brake is released.
Since the configuration is such that the generation of abnormal noise due to the collision with the first member is prevented, the operational effects of the first invention can be easily achieved, for example, the dimensional control of the tubular member 21 is easy.

In the duo-servo type drum brake device according to the third aspect of the present invention, the cylindrical member 21 is formed into a cylindrical shape whose inner diameter is larger than the outer diameter of the anchor pin 7, and the gap δ between them is set. The object of the second invention can be achieved at low cost.

The cylindrical member 21 and the anchor pin 7 (3
7, 38), the cylindrical member 21 is formed into a barrel shape as illustrated in FIG. 8 as in the fourth invention, and the cylindrical member 21 and the anchor pin 7 are formed.
(37, 38), or the fifth gap δ.
As shown in FIG. 9, the tubular member 21 is formed into a drum shape as illustrated in FIG. 9, and the tubular member 21 and the anchor pins 7 (37, 3) are formed.
8) can be set.

In the duo-servo type drum brake device according to the sixth aspect of the present invention, the cylindrical member 21 is formed by rolling a plate material, but the slit 21a is left between both ends of the plate material opposed by the roll processing. Since the slit 21a remains, the elastic deformation of the tubular member 21 in the second to fifth inventions is ensured,
When the brake is released, the tubular member 21 is
(37, 38) so as to completely eliminate the gap δ, and as a result, the brake shoes 3, 4 (34, 35)
Dragging by the inner peripheral surface of (32) can be avoided.

In the duo-servo type drum brake device according to the seventh aspect of the invention, since the tubular member 21 is made of a spring steel plate,
The elastic deformation of the tubular member 21 is ensured, and the effects of the second to sixth inventions can be further enhanced.

In the duo-servo type drum brake device according to the eighth aspect of the invention, the cylindrical member 21 (48, 49) is made of a damping steel plate, and the above-mentioned damping is performed according to the material characteristics of the damping steel plate. Even if a strict gap δ is not set between the shaped member 21 (48, 49) and the anchor pin 7 (37, 38), a reliable countermeasure against abnormal noise can be achieved while achieving the same operation and effect as in the above inventions. Can be applied.

In the duo-servo type drum brake device according to the ninth invention, the anchor pin 7 is connected to both brake shoes 3 and 4.
In the case of a single anchor pin common to
1 is configured to perform the buffering by being diametrically pressed between the corresponding adjacent ends of the two brake shoes 3 and 4, so that a countermeasure against abnormal noise particularly useful in a single anchor type duo servo type drum brake device is provided. Can be provided.

In the duo-servo type drum brake device according to the tenth aspect of the present invention, when the anchor pins 37, 38 are double anchor pins individually installed on both brake shoes 34, 35, the cylindrical member 21 (48, 49) is used. ) Is clamped between the anchor pins 37 and 38 and the corresponding ends of the brake shoes 34 and 35 to perform the above-described buffering. Even in a double anchor type duo servo type drum brake device in which a configuration in which a member is diametrically pressed and elastically deformed cannot be adopted, a reliable noise countermeasure can be taken.

The duo-servo type drum brake device according to the eleventh aspect of the present invention is characterized in that the distal end of the cylindrical member 21 (48, 49)
A shoe guide plate 9 (50, 50) for preventing the one adjacent end of the brake shoes 3, 4 (34, 35) from coming off in the axial direction with respect to the anchor pin 7 (37, 38).
51), the shoe guide plate 9
The (50, 51) is integrated with the tubular member 21 (48, 49), so that the handling of both is simplified, and the number of components is reduced, which is advantageous in cost.

[Brief description of the drawings]

FIG. 1 is a front view showing a single anchor type duo servo type drum brake device according to an embodiment of the present invention with a brake drum removed.

FIG. 2 shows a structure around an anchor pin of the drum brake device according to the embodiment, and is a II-II in FIG. 1;
FIG. 3 is a detailed enlarged cross-sectional view as seen from the line in the direction of the arrow.

FIG. 3 is an explanatory diagram of an operation in a braking process of the drum brake device according to the embodiment.

FIG. 4 is a perspective view showing another example of a tubular member used for countermeasures for abnormal noise when a brake is released in the present invention.

FIG. 5 is a perspective view showing still another example of the tubular member.

FIG. 6 is a front view showing a double anchor type duo servo type drum brake device according to another embodiment of the present invention with a brake drum removed.

FIG. 7 shows a detailed structure around the anchor pin of the drum brake device according to the embodiment; FIG.
FIG. 2 is an enlarged cross-sectional view taken along line II and viewed in the direction of the arrow.

FIG. 8 is a perspective view showing still another example of the tubular member.

FIG. 9 is a perspective view showing still another example of the tubular member.

FIG. 10 is an enlarged sectional view similar to FIG. 7, showing the tubular member of FIG. 8 applied to a double anchor type duo servo type drum brake device.

11 is an enlarged sectional view similar to FIG. 7, showing the cylindrical member of FIG. 9 applied to a double anchor type duo servo type drum brake device.

[Explanation of symbols]

 Reference Signs List 1 back plate 2 brake drum 3 brake shoe 4 brake shoe 5 brake shoe holding mechanism 6 brake shoe holding mechanism 7 anchor pin 8 shoe gap adjuster 9 shoe guide plate 10 upper shoe return spring 11 upper shoe return spring 12 lower shoe return spring 13 wheel Cylinder 14 Push rod 15 Push rod 16 Parking brake operating lever 17 Pivot pin 18 Strut 19 Anti-rattle spring 20 Brake cable 21 Tubular member 31 Torque plate 32 Brake drum 33 Dust cover 34 Brake shoe 35 Brake shoe 34d Anchor hole 35d Anchor hole 36 Shoe gap adjuster 37 Anchor pin 38 Anchor pin 39 Shoe return spring 40 Shoe return spring 41 Adjust , Spring 42 cam 43 the bracket 44 stiffener 45 brake operating lever 46 the operating lever return spring 47 the lever stopper 48 cylindrical member 49 cylindrical member 50 shoe guide plate 51 shoe guide plates

Claims (11)

[Claims] 1. A pair of brake shoes, one adjacent end of which is in elastic contact with a fixed anchor pin, and the other adjacent end of which is in contact with both ends of a link interconnecting these adjacent ends. The two brake shoes are expanded so that the one adjacent end is separated from the anchor pin and brought into contact with the inner peripheral surface of the brake drum, and the two brake shoes connected by the link are integrally formed. In a duo-servo type drum brake device that performs a braking action by rotating and abutting on an anchor pin, a tubular member is fitted to the anchor pin, and the one of the two brake shoes is buffered through the tubular member. A duo-servo type drum brake device characterized in that it is configured to receive adjacent ends respectively. 2. The buffer according to claim 1, wherein a gap is set between the anchor pin and the tubular member fitted to the anchor pin, and the tubular member is elastically deformed by the gap. A duo-servo type drum brake device characterized in that it is configured to perform 3. The duo-servo type drum brake device according to claim 2, wherein the cylindrical member has a cylindrical shape whose inner diameter is larger than the outer diameter of the anchor pin, and the gap is set between them. . 4. The duo servo type drum brake device according to claim 2, wherein the cylindrical member is formed into a barrel shape, and the gap between the cylindrical member and the anchor pin is set. 5. The duo-servo type drum brake device according to claim 2, wherein said tubular member is shaped like a drum and said gap is set between said tubular member and said anchor pin. 6. The slit according to claim 2, wherein the cylindrical member is formed by rolling a plate material, but a slit remains between both ends of the plate material opposed by the roll processing. A duo-servo type drum brake device comprising a cylindrical member. 7. The duo-servo type drum brake device according to claim 2, wherein the tubular member is made of a spring steel plate. 8. The duo-servo type drum brake device according to claim 1, wherein the cylindrical member is made of a damping steel plate, and the buffering is performed according to a material characteristic of the damping steel plate. 9. The brake device according to claim 1, wherein the tubular member has a diameter between the corresponding adjacent ends of the brake shoes when the anchor pin is a single anchor pin common to both brake shoes. A duo-servo type drum brake device characterized in that the buffering is performed by being pinched in a direction. 10. The method according to claim 1, wherein the anchor pin is a double anchor pin individually installed for both brake shoes. A duo-servo type drum brake device, wherein a cylindrical member is sandwiched between an anchor pin and a corresponding end of a brake shoe to perform the buffering. 11. A shoe according to claim 1, wherein the one end of the brake shoe is prevented from coming off in the axial direction with respect to the anchor pin at the tip of the tubular member. A duo-servo type drum brake device characterized in that a guide plate is integrally formed.