JPH10159883A - Shoe space automatically adjusting device of drum brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To substantially integrate a shoe space automatically adjusting device for easy handling and improve the assembly in a drum brake assembling line. SOLUTION: A shoe space automatically adjusting device has a strut with an expandable screw mechanism, an adjusting lever 19 to automatically rotate the screw mechanism and extend the total length of the strut 13 and an adjusting spring 20 to grant the rotating force to the adjusting lever 19. The adjusting spring 20 is extendedly provided between the adjusting lever 19 and the strut 13 to be substantially integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically adjusting a shoe clearance of a drum brake, and in particular, to substantially integrate these components in order to improve the handling and assembly workability of the adjusting device. It is related to the structure to be performed.

[0002]

2. Description of the Related Art For example, Japanese Patent Publication No. 1-58374 is known as an automatic shoe gap adjusting device of this type, and its structure will be outlined with reference to FIG.

S1 and S2 are brake shoes movably mounted on a back plate P. A wheel cylinder C, which is a shoe expanding device, is disposed between upper facing ends of the brake shoes. Is provided with an anchor member A,
Each is fixed to the back plate P.

[0004] Brake drum and brake shoes S1, S
An automatic shoe gap adjusting device for automatically adjusting the gap between the strut member S and the strut member S disposed between the brake shoes S1 and S2 adjacent to the wheel cylinder C is provided. It comprises a lever L1 and an adjusting spring B.

The strut member S comprises an adjusting bolt b, an adjusting nut n, and a tube member t. One side of the nut n screwed to the bolt b comes into contact with the open end surface of the tube member t, and the bolt b projects. The part is loosely fitted to the tube member t. The ends of the adjustment bolt b and the tube member t are crushed to have a fork shape, and are engaged with one of the brake shoes S1 and a brake lever L2 described later.

The adjusting lever L1 has an intermediate portion rotatably supported by one of the brake shoes S1 with a pin P1. One arm of the adjusting lever L1 is engaged with the adjusting nut n, and the other arm is connected to the tube member t. An adjust spring B is stretched between the extension of the other arm and one of the brake shoes S1 so as to contact the end face. In other words, the adjusting spring B is connected to the adjusting lever L
1, a counterclockwise rotation force about the pin P1 as a fulcrum, and a biasing force such that one arm of the lever L1 always engages with the outer peripheral teeth of the adjust nut n.

L2 is a parking brake lever, one end of which is connected to the other brake shoe S2 by a pin P2.
Thus, a control cable (not shown) serving as a remote control means is connected to the other end. R
1 and R2 are shoe return springs, and H1 and H2 are shoe hold devices.

Next, the operation of the brake constructed as described above will be described.

First, when the wheel cylinder C is pressurized at the time of service braking, both brake shoes S1 and S2 expand at their contact points with their anchor members A as fulcrums, and a rotating brake drum (not shown). ) Is frictionally engaged to brake this.

Next, when the control cable (not shown) is pulled during parking brake, the lever L2 rotates clockwise about the pin P2, and the acting force is transmitted to one brake shoe S1 via the strut member S. The shoe S1 is expanded with its contact point with the anchor member A as a fulcrum, and frictionally engages with a brake drum (not shown). Then, the reaction force acts on the pin P2, and the other brake shoe S2 also expands in the same manner, and frictionally engages with a brake drum (not shown), thereby keeping the brake drum (not shown) stopped.

Next, the operation of the automatic shoe clearance adjustment constructed as described above will be described.

Now, when the wheel cylinder C is pressurized by the service brake and both brake shoes S1 and S2 are opened, the adjusting lever L1 is rotated counterclockwise by the urging force of the adjusting spring B, and the strut member S is rotated.
Follow the lever L2 cooperating with the other brake shoe S2. The pin P1 pivot of the adjust lever L1 cooperates with one of the brake shoes S1. At this time, when the rotation amount of one arm of the adjustment lever L1 exceeds the pitch between the teeth of the adjustment nut n, the nut n is rotated and the adjustment bolt b is pulled out from the tube member t by one tooth corresponding to one tooth. And the gap between the brake drum (not shown) and the brake shoes S1, S2 is always kept constant.

[0013]

Here, the automatic shoe gap adjusting device having the above configuration has the following problems. <A> If the total length of the strut is set to a predetermined length in the preparatory stage, it is convenient because the work of adjusting the diameter of the brake shoe is not required in a later step. However,
Since the tube member is merely loosely fitted to the adjustment bolt, the tube member is easily pulled out at the time of its handling. I was sorry. <B> The adjustment lever and the adjustment spring that constitute the automatic shoe clearance adjustment device are mounted on the brake shoes. Therefore, in order to automate the assembly line, a robot mechanism that moves complicatedly is required. It was difficult.

[0014]

SUMMARY OF THE INVENTION The present invention provides an automatic shoe clearance adjusting device without increasing the number of components.
It is an object of the present invention to solve the above-mentioned problem by substantially integrating the above-mentioned device by designing it.

[0015] To this end, an automatic shoe gap adjusting device for a drum brake according to the first aspect of the present invention is provided.
A shoe gap for disposing a shoe expanding device between one opposing ends of a pair of brake shoes and an anchor device between the other opposing ends to automatically adjust by detecting the expanding amount of both brake shoes. An automatic adjusting device is provided between the two brake shoes adjacent to the shoe expanding device, wherein the automatic shoe clearance adjusting device for a drum brake has a strut having an extendable screw mechanism. And an adjusting lever for automatically rotating the screw mechanism to extend the entire length of the strut, and an adjusting spring for applying a rotating force to the adjusting lever, wherein the adjusting spring is disposed between the adjusting lever and the strut. A drum brake, wherein the components of the automatic shoe gap adjusting device are substantially integrated. And of the automatic shoe clearance adjustment device.

Further, the automatic shoe gap adjusting device for a drum brake according to a second aspect of the present invention is provided with the first aspect.
In the invention, there is provided an automatic shoe gap adjusting device for a drum brake, wherein a regulating means for regulating excessive rotation of an adjusting lever due to the adjusting spring force is provided between the lever and the strut.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS.

Reference numeral 1 denotes an immobile back plate on which opposed brake shoes 2 and 3 are movably mounted. The shoes 2, 3 are formed in a T-shaped cross section from rims 4, 4 and webs 5, 5, respectively, and linings 6, 6 are fixed to the outer periphery of the rims 4, 4.

Reference numeral 7 denotes a wheel cylinder disposed between the upper opposed ends of the brake shoes 2 and 3 for operating the brake shoes 2 and 3 to expand by a service brake. The wheel cylinder 7 is fixed to the back plate 1 with bolts or the like. As well as
The pistons 7a, 7a lightly abut the upper facing ends of the webs 5, 5, respectively.

Reference numeral 8 denotes an anchor device for supporting the lower opposing ends of the brake shoes 2 and 3, which are fixed to the back plate 1 with two rivets 9, 9. The anchor device 8 of the present embodiment has a plate shape, but may have a pin shape. Reference numeral 8a denotes an extension portion extending from the anchor device 8, and a portion for guiding a control cable for remote traction operation (not shown).

Reference numeral 10 denotes a parking brake lever.
It is a component that is built in if necessary. The lever 10 is disposed so as to overlap with the web 5 of the brake shoe 3, and its base 10a has a pin 11 near the upper end of the web 5.
As a result, a U-shaped groove for connecting a control cable (not shown) for remote traction operation is formed in the free end portion 10b by turns. Reference numeral 10c denotes a protrusion for restricting the return position of the lever 10 when the brake is not operated, and is in contact with the inner surface of the rim 4.

Reference numeral 12 denotes an automatic shoe clearance adjusting device, which includes a strut 13 suspended between the two brake shoes 2 and 3 adjacent to the wheel cylinder 7 and an adjusting lever 1.
9 and an adjusting spring 20.
The strut 13 is composed of a bolt member 14, a nut member 15, and a tube member 16. The nut member 15 is screwed into the male screw shaft portion 14a of the bolt member 14, and the protruding portion is loosely fitted to the tube member 16. Tube member 1
6 has an opening end surface in contact with one side surface of the nut member 15.

Notched grooves 14b, 16b are respectively formed in the crushed plate-like portions at the ends of the bolt member 14 and the tube member 16, and the bottom of the notched grooves 14b abuts on the lever 10, and the notched grooves 16b are formed. The bottom abuts the web 5 of the brake shoe 2. Small nuts 15a, for example, saw-tooth teeth, are formed on the outer periphery of the nut member 15.

The adjusting lever 19 is substantially in the shape of a fishing hook. One of the grooves 19a is in contact with the stepped surface 16c of the cutout groove 16b of the tube member 16, and the other end 19b is bent. Are in contact with the small teeth 15 a of the nut member 15. A bent portion 19c is formed at an intermediate portion of the lever 19 so as to be in contact with the web 5 of the brake shoe 2, and a portion adjacent to the other bent portion 19b can be brought into contact with the outer periphery of the tube member 16. A bent portion 19d is formed.

The adjusting spring 20 has its coil wound around the bolt member 14 and the hooks 20a, 20b at both ends.
b is a stepped surface 14c of the notch groove 14b of the bolt member 14.
And a protrusion 19e adjacent to one of the grooves 19a of the adjuster lever 19. Due to this tension, a counterclockwise rotational force is applied to the adjusting lever 19 with the bottom of the notch groove 16b of the tube member 16 in contact with the bottom of one groove 19a as a fulcrum, and the other bent portion 19b is gradually A biasing force is applied to engage the teeth 15a, and an axial force is applied to the struts 13.

As is apparent from the assembly drawings of the automatic shoe gap adjusting device 12 shown in FIGS. 2 and 3, excessive rotation of the adjusting lever 19 is restricted by the bent portion 19d abutting on the tube member 16, so that All members constituting the adjusting device 12 can be substantially integrated.

Therefore, the handling and transportation are easy, and the effective length of the strut 13 can be set in advance, so that the brake assembly in the subsequent process becomes very easy.

Numerals 21 and 22 denote shoe return springs extending between the upper and lower portions of the brake shoes 2 and 3. When the shoe gap automatic adjusting device 12 is installed between the brake shoes 2 and 3 by this tension, The bent portion 19c of the adjusting lever 19 is pressed by the web 5, and the lever 19 is rotated clockwise about the contact point with the stepped surface 16c of the tube member 16 and held at a predetermined position. At this time, the rotation amount of the other bent portion 19b is set to be larger than the pitch between the small teeth 15a.

Reference numerals 23 and 24 denote known shoe hold devices for supporting the brake shoes 2 and 3 on the back plate 1.

[0030]

[Brake operation] Regarding the operation of the service brake and the operation of the parking brake in the above configuration,
The description is omitted because it is the same as the conventional example described above.

[0031]

[Operation of Automatic Shoe Gap Adjustment] Next, the operation of the automatic shoe gap adjustment in the above-described configuration will be described.

In FIG. 1, when the wheel cylinder 7 is pressurized, the brake shoes 2 and 3 are expanded right and left around the contact point with the anchor device 8 as a fulcrum and frictionally engage with a brake drum (not shown). . At this time, the adjusting lever 19 rotates counterclockwise around the contact point with the stepped surface 16c of the tube member 16 by the action force of the adjusting spring 20, and the bent portion 19c follows the brake shoe 2 and Further, the brake shoe 2 is further rotated around the contact point of the brake shoe 2 with the web 5, and the strut 13 follows the lever 10 which moves integrally with the brake shoe 3.

However, now, the linings 6, 6 are worn,
When the rotation amount of the other bent portion 19b of the adjustment lever 19 exceeds the pitch between the small teeth 15a of the nut member 15, the nut member 15 is rotated by one tooth and the bolt member 1 is rotated.
4 is automatically screwed out of the tube member 16 so that the gap between the brake drum (not shown) and the brake shoes 2 and 3 is always kept constant.

[0034]

Embodiment 2 FIGS. 4 to 6 show an embodiment of an automatic shoe gap adjusting device 112 applied to another strut mechanism.

From a functional point of view, the same members as those in the above-described first embodiment will be described with reference numerals of the hundreds.

The strut 113 includes a bolt member 114, a tube member 116, and a socket member 117. An adjusting tooth wheel 114d is formed integrally with an intermediate portion of the bolt member 114, and a left external screw shaft portion 114a thereof is screwed into a female screw 116a of the tube member 116, and a right shaft portion 114e is formed of a socket. It is loosely fitted in the hole of the member 117. Also, the tube member 116 and the socket member 1
The end of the tube member 17 is crushed into a flat plate shape.
The flat plate portion 16 has a cutout groove 116b for receiving the web 5 and the lever 10, and the flat plate portion of the socket member 117 has a cutout groove 117b for receiving the web 5 therein.

The adjusting lever 119 has the daruma hole 1
19a is a pin 1 implanted in a flat plate portion of the socket member 117.
18, the first arm 1 is rotatably and tiltably pivotally supported.
19b is in contact with the adjusting gear wheel 114d, and the second arm 119c is in contact with the web 5 so that the socket member 11 is in contact with the web 5.
7, the third arm 119d extends toward the notch groove 11b.
Of the first arm 119 with respect to the axis of the strut 113.
b on the opposite side, and this extension has an adjustment wheel 114
d, a contact portion 119f that contacts the side surface of the tube member 116 to prevent the socket member 117 from being pulled out, and a bent portion 119g that contacts the outer periphery of the tube member 116 and restricts excessive rotation of the adjustment lever 119. Are formed.

The adjusting spring 120 has a projecting hook 119 e projecting from the first arm 119 b of the adjusting lever 119 and a stepped surface 117 at the end of the socket member 117.
With this tension, a counterclockwise rotational force is applied to the adjustment lever 119 with the pin 118 as a fulcrum, and the first arm 119b is moved to the adjustment toothed ring 114d.
And a biasing force is applied so as to abut and engage.

However, the assembly state of the automatic shoe gap adjusting device 112 is shown in FIG.
9, when the bent portion 119g abuts against the outer periphery of the tube member 116, the right end surface of the second arm 119c is set to protrude from the bottom of the cutout groove 117b of the socket member 117 by a predetermined amount. The amount of protrusion may be set so that the amount of rotation of the second arm 119c is equal to or greater than the pitch between the teeth of the adjustment gear wheel 114d. As is apparent from the above-described configuration, the automatic adjustment device 112 can also be substantially integrated, so that the same effects as those of the first embodiment described above can be obtained.

[0040]

[Operation of Automatic Adjustment of Shoe Gap] As shown in FIG. 6, the adjust lever 119 at the time of the drum brake assembly is adjusted by the tension of the shoe return spring 21 so that the second arm 119c is moved.
Is flush with the bottom of the cutout groove 117b of the socket member 117.

In the first embodiment, the type of automatic adjustment when the brake is operated, that is, the so-called on-stroke type is shown. In the present embodiment, the type of automatic adjustment when the brake is released, that is, the so-called off-stroke type is shown. ing. The change between the on-stroke type and the off-stroke type can be easily performed by changing the direction of the sawtooth-shaped teeth and the screw.

Now, from the state shown in FIG.
Is expanded, the second arm 119c of the adjustment lever 119 is rotated counterclockwise about the pin 118 by the tension of the adjustment spring 120 to rotate the brake shoe 2.
The strut 113 follows the brake shoe 3 via the pin 118 with the contact point as a fulcrum. At this time, if the amount of rotation of the first arm 119b exceeds the inter-tooth pitch of the adjusting gear wheel 114d, the adjusting gear wheel 114d is rotated when the brake is released to extend the strut 113.

[0043]

According to the present invention, the following effects can be obtained. <A> Since the strut length can be set in advance, the work for adjusting the shoe gap in the subsequent process is not required, and the number of man-hours can be reduced. <B> Since the automatic shoe gap adjusting device can be handled as one assembly, it is particularly easy to automate the brake assembly line. <C> Since all components of the automatic shoe gap adjusting device are substantially integrated, there is no possibility that the components will be separated and lost or damaged during handling. <2> Further, since it is not necessary to separately take a strut separation preventing means during the transportation, the cost can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 is an example of a front view of a drum brake device according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view showing an assembled state of the automatic shoe gap adjusting device of FIG. 1;

FIG. 3 is a bottom view of FIG. 2;

FIG. 4 is a bottom view of an example of an enlarged view showing an assembled state of the automatic shoe gap adjusting device according to Embodiment 2 of the present invention;

FIG. 5 is a state diagram when the automatic shoe gap adjusting device of FIG. 4 is used as a drum brake assembly;

FIG. 6 is a bottom view of FIG. 5;

FIG. 7 is a front view of a drum brake device according to a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Back plate 2, 3 Brake shoe 7 Wheel cylinder 8 Anchor device 10 Lever for parking brake 12, 112 Shoe gap automatic adjustment device 13, 113 Strut 14, 114 Bolt member 15 Nut member 16, 116 Tube member 19, 119 Adjust lever 20,120 Adjusting spring 21,22 Shoe return spring 117 Socket member

Claims (2)

[Claims] 1. A shoe expanding device is provided between one opposing ends of a pair of brake shoes, and an anchor device is provided between the other opposing ends. An automatic shoe gap adjusting device for adjusting the distance between the brake shoes is provided between the brake shoes adjacent to the shoe expanding device. A strut having a screw mechanism, an adjusting lever for automatically rotating the screw mechanism to extend the entire length of the strut,
The adjusting lever is provided with an adjusting spring that applies a rotational force to the adjusting lever, and the adjusting spring is stretched between the adjusting lever and the strut to substantially integrate the constituent members of the automatic shoe gap adjusting device. A special feature is an automatic shoe clearance adjustment device for drum brakes. 2. The automatic shoe clearance of a drum brake according to claim 1, wherein a restricting means for restricting an excessive rotation of the adjusting lever by the adjusting spring force is provided between the lever and the strut. Adjustment device.