JPH0419247Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an anchor part structure of a drum brake used in vehicles and the like.

[Conventional technology and its problems]

First, before explaining the conventional anchor structure,
The operating principle and basic configuration of this type of device will be explained with reference to FIG. 9.

In FIG. 9, it is assumed that the automobile is traveling on a slope S in the direction of arrow F. Therefore, wheel 1 is indicated by arrow A
It rotates in the direction. As is well known, a wheel cylinder 2 is fixed to a back plate 3 fixed to the vehicle body side, and a pair of arcuate cylinders 4 are attached to the wheel cylinder 2.
The upper ends of a and 4b are pivotally connected. Further, the lower end portion is in contact with both end portions 6a and 6b of the sliding anchor 6. The sliding anchor 6 is slidable into the through hole of the anchor body 7 fixed to the back plate 3, and both ends 6a and 6b abut against the anchor body 7, so that the sliding anchor 6 can be moved to the rightward movement position. The left forward movement position is restricted. In the figure, the left forward movement position is shown. As clearly shown in FIG. 7, the switch body 8 is housed within the anchor body 7, and one end 6b abuts the switch actuator 9.
The actuator 9 is biased to the left by a spring inside the main body 8, although not shown, and is off in the illustrated state.

The upper end portions of the shoes 4a and 4b are urged inward by an upper return spring 10a, and the lower portions of the shoes 4a and 4b are a pair of lower return springs 10b, each of which has one end latched to the central protrusion 7a of the anchor body 7. , 10c. The spring force of the lower return spring 10c on the right side is greater than the spring force of the lower return spring 10b on the left side, so that the one end 6a of the sliding anchor 6 is always biased in the direction of contacting the anchor body 7 as shown in the figure. and show 4a, 4
b prevents the switch from malfunctioning due to rattling when the car is running.

The brake configured as above is called
It is called the LT type drum brake, and one
A is called a leading show, and the other show 4b is called a trailing show. Now, when a brake pedal (not shown) is depressed to stop the automobile, pressurized fluid is supplied to the wheel cylinder 2, and the brake linings of the shoes 4a, 4b are pressed against the drum 5 that rotates together with the wheel 1. A frictional force is generated between the shoes 4a, 4b and the drum 5 in the direction opposite to the rotating direction of the drum 5 (direction of arrow A), and this provides a braking force, but it is of the same magnitude as the frictional force. The reaction force in the opposite direction acts as a brake reaction force as shown by arrows B and C,
The leading side shoe 4a comes into contact with one end 6a of the sliding anchor 6 due to the sum of the pressing force from the piston in the wheel cylinder 2 and the reaction force B, and the triling side shoe 4b contacts the other end 6b based on the difference. comes into contact with. Further, the leading side shoe 4a comes to abut firmly against the one end portion 6a due to the self-servo action. As a result, the force pushing the sliding anchor 6 to the left in the figure is greater, so the sliding anchor 6 continues to take the left forward movement position shown, and the switch 8 remains off.

When the car stops and the clutch is released, the wheel 1 receives a turning force in the direction opposite to arrow A due to gravity. That is, the vehicle is subjected to back torque that attempts to move it to a lower location. The direction of the frictional force acting between the shoes 4a, 4b and the drum 5 is reversed and becomes the direction of arrow B or C, but its magnitude is larger on the trailing side shoe 4b side, and the sliding anchor 6 is It slides to the right in the figure and assumes the right forward movement position. As a result, the actuator 9 of the switch 8 is pressed and turned "on". This "ON" signal causes a solenoid valve, which will be described later, to close, and the master cylinder side and the wheel cylinder 2 side are cut off, and the brake is maintained even if the foot is released from the brake pedal.
The clutch pedal can be kept away from the foot in the shuttral position.

When starting an automobile, the clutch pedal is depressed in a half-clutch state and the accelerator pedal is depressed, thereby transmitting driving torque to the wheels 1, that is, the drums 5 in the direction of arrow A. As a result, show 4
The frictional force between a, 4b and the drum 5 is reversed again, and a brake reaction force as shown by arrows B and C acts on the shoes 4a, 4b, and the sliding anchor 6 moves to the left, as shown in the figure. Takes the left forward movement position. That is, the switch 8 is turned off, the solenoid valve (not shown) is opened, and the master cylinder side and the wheel cylinder 2 side are in communication. In this way, the hydraulic pressure in the wheel cylinder 2 is released to the master cylinder side, the brake is released, and the vehicle starts moving.

As a means for providing the above-mentioned switch 8 on the anchor body 7 of the drum brake, there is a method disclosed in the patent application filed in 1983-
90491 (Japanese Unexamined Patent Publication No. 61-247550), this will be explained in detail below with reference to FIGS. 6 to 8.

The sliding anchor 6 of this conventional example has a pair of shaft members 1
3a and 13b, and is slidably fitted into the center through hole 12 of the anchor body 7. The anchor body 7 is fixed to the back plate 3 with bolts 11a and 11b.

The anchor body 7 is further formed with a recess 15 parallel to the center through hole 12, into which the switch 8 is fitted, and a U-shaped stopper 19 is engaged with the groove of the switch 8 body. It is fixed to the anchor body 7 by. The switch actuator 9 is biased to the left by a spring within the switch 8 body, and is slidable relative to the switch 8 body. The coat 14 covering the wire from the switch 8 is led out to the outside through a through hole 16 formed in communication with the recess 15. The inside of the through hole 16 is filled with mode m.

The actuator 9 of the switch 8 is one shaft member 13b.
The switch 8 is in contact with the protrusion 6b (one end of the sliding anchor 6), and in the illustrated state, the switch 8 is off. Moreover, both ends 6a and 6b of the sliding anchor 6
Rubber boots 18a and 18b are stretched between the anchor body 7 and both ends of the anchor body 7 to prevent dirt and water from entering the anchor body 7.

The conventional example is configured as above,
A cord 14 is directly attached to the switch 8, and is led out through a hole 16 in the anchor body 7. Since the electrical equipment connected to the cord 14 is generally located behind the back plate 3, the cord 14 must also be guided to these electrical equipment through holes formed in the back plate 3. The hole 16 leading out from the anchor body 7 is sealed by filling it with a mold m, but it is also necessary to seal the hole 16 with the hole in the back plate 3 even though it is not shown. The work is complicated. Therefore, manufacturing efficiency is low. Also, it is clear that replacing the switch is very difficult.

[Problem that the invention attempts to solve]

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide an anchor part structure of a drum brake that facilitates attachment and detachment from a vehicle etc. and improves productivity.

[Means for solving problems]

The above object consists of a block fixed to a back plate fixed to a non-rotating part of the vehicle body, a hole provided through the block, and a block fitted into the hole so as to be movable at a predetermined distance, each end having a brake. A drum brake comprising: a movable member that contacts the shoe; a second hole formed in the block in line with the hole; and a switch disposed in the second hole and switched by movement of the movable member. In the anchor part structure, a third hole is formed that penetrates the block and back plate from the second hole and opens to the outside, and a connecting part is provided on the switch to allow a connecting tool to be attached and detached, and this connecting part is provided. On the other hand, this is achieved by the anchor part structure of the drum brake which allows the connecting tool to be attached and detached through the third hole.

[Effect]

The cord is electrically connected to the switch by simply pushing the connector through the third hole toward the switch, so the connection work is extremely simple. In addition, the disconnection work is easy because the connector can be separated from the switch by simply pulling out the connector. Since the third hole also passes through the back plate, sealing work is easy and productivity can be improved.

〔Example〕

Next, the structure of the anchor part of the drum brake according to the embodiment of the present invention will be explained with reference to FIGS. 1 to 4.

The figure shows only the structure of the anchor part, but the other structure is exactly the same as the drum brake shown in FIG. 9. Note that parts corresponding to those in the conventional example are given the same reference numerals.

In the figure, the downward protrusion 2 of the anchor body 20
1 fits into an opening 3a formed in the back plate 3, and is fixed to the back plate 3 with bolts 23a and 23b with a cover 22, which will be described later, interposed therebetween.

A through hole 24 is formed in the upper part of the anchor body 20, into which a pair of shaft members 25a and 25b serving as a sliding anchor are slidably fitted.

Outer ends 26a, 26 of shaft-like members 25a, 25b
Rubber boots 27a and 27b are stretched between the flanges b and the open end of the through hole 24 to prevent water and dirt from entering the through hole 24.

A switch mounting hole 28 is further formed in the anchor body 20 in line with the through hole 24, into which a switch 31 is fitted. The details of this switch 31 are shown in FIG. 4, and a rubber boot 30 is fixed to the open end of the hole 28 so as to cover its operating rod 32. It is fitted with a lock that prevents it from falling out. The bottom 30a of the rubber boot 30 is thick, and is in contact with the end 26b of the shaft-like member 25b. That is, the operating rod 32 of the switch 31 is in contact with the end 26b of the shaft member 25b via the bottom 30a of the rubber boot 30. The actuating rod 32 is biased to the left in FIG. 2 by a spring built into the switch 31. The anchor body 20 further includes a hole 33 extending in the vertical direction.
A connector 35, the details of which are shown in FIG. 4, is fitted into this to electrically connect the harness cord 34 to the switch 31.

Further, the above-mentioned cover 22 is fixed to the back plate 3 so as to cover the hole 33, and the harness cord 34 is tightly supported by the cylindrical portion 22a of the cover 22.

Next, details of the switch 31 and the connector 35 will be explained with reference to FIG.

The switch 31 has a main body 43 made of a cylindrical synthetic resin.
, from which the aforementioned actuating rod 32 projects. A contact support member 45 made of an insulating material is fixed to the main body 43, and a rotation preventing protrusion 46 is formed on the upper wall portion (in FIG. 4). Further, a rotation preventing protrusion 44 is formed on the main body 43 in alignment with this.

The contact support member 45 has an extension part 47 on the upper wall part, and a hanging part 48 is integrally formed downward from the extension part 47. Contacts 49a and 49b are supported on both sides of this hanging portion 48 with a predetermined gap therebetween, and these extend into the main body 43 through a support member 45 made of an insulating material. In addition, contact 49
Small holes 50a and 50b are formed in a and 49b.

In the connector 35, a main body 51 made of an insulating material
The above harness code 34 is derived from
The contacts 53a and 53b protrude from the main body 51 so that approximately half of the contacts 53a and 53b are located within the recess of the approximately semicircular protrusion 52. The contacts 53a, 53b are formed by bending a flat plate into a V-shape or a U-shape, and small protrusions 55a, 55b are formed on the outer surface of each. Furthermore, a predetermined gap is formed between the outer surfaces of the contacts 53a, 53b and the side walls 52a, 52b of the protrusion 52. The gap between the contacts 53a and 53b is approximately equal in size to the width of the hanging portion 48 of the switch 31. A rotation prevention protrusion 5 is provided on the side wall of the main body 51.
4 is formed.

The switch 31 is connected to the hole 2 of the anchor body 20 described above.
A groove is formed in the inner wall of the hole 28, and the protrusions 44 and 46 fit into the groove, and the switch 3 is inserted into the hole 28.
1 is designed to be prevented from rotating. That is, it is positioned in the hole 28.

When inserting the connector 35 into the hole 33 of the anchor body 20, insert the body 5 into the groove formed on the inner wall of the hole 33.
When the contacts 53a and 53b are inserted while engaging the protrusion 54 of the switch 31, the contacts 53a and 53b fit between the hanging portion 48 of the switch 31 and the contacts 49a and 49b.
The small protrusions 55a and 55b of a and 53b are the switch 3
Small holes 50a, 50b of contacts 49a, 49b on the 1 side
Both contacts 49a, 49b and 53a,
53b are fixed to each other.

The embodiment of the present invention is configured as described above,
Next, this action, effect, etc. will be explained.

Assume that the car is currently climbing a slope and the brake pedal is depressed to stop the car. As explained with reference to FIG. 2, the sliding anchor 20 is pushed to the right in FIG. 2 by one shoe 4b. The actuating rod 32 of the switch 31 is connected to the boot 3 by one end 26b of the sliding anchor 20.
0, and the switch 31 is turned on. As a result, a solenoid valve (not shown) connected to the cord 34 is closed, and pressurized fluid is held in the wheel cylinder 2. The starting operation of the automobile is as described above, but at this time the sliding anchor 20 is in the second position.
Moving to the left in the figure, the actuating rod 32 of the switch 31 is moved back to the illustrated position by the spring built into the switch 31.

The switch 31 performs the above-mentioned operation, and the repeating operation rod 32 moves the sliding anchor 2.
Even if an impact force is applied by the end 26b of the boot 30, the impact force is alleviated and the actuating rod 9 is not damaged because it is applied through the bottom 30a of the boot 30. No wear powder is generated. Furthermore, since the boot 30 covers the open end of the hole 28, water and foreign matter do not enter the switch 31, thereby improving its durability.

Further, the electrical connection between the switch 31 and the cord 34 can be made simply by inserting the connector 35 into the hole 33, so it is very simple. Also, removal is very easy as it is only necessary to pull out the connecting tool 35 downward from the hole 33. Further, since the harness cord 34 is led out directly below the back plate 3, the structure of the seal is simple. cover 22
It is done only by

FIG. 5 shows a modification of the switch and connector, which has a simpler structure than the above embodiment.

The switch 60 and the connector 61 of this modification are also inserted into the holes 28 and 33 of the anchor body 20 in the same way as described above, but the switch 60 is inserted into the holes 28 and 33 of the anchor body 20.
Rotation is prevented by a protrusion 63 formed on 2. A pair of contacts 65a and 65b are located below an arcuate protrusion 66 of the support member 4 made of an insulating material and integrally fixed to the main body 62. These contacts 6
5a and 65b pass through the support member 64 and attach to the main body 62.
extending inward. 67 is an operating rod.

In the connector 61, a main body 6 made of synthetic resin is used.
8 is also formed with a rotation prevention protrusion 71, and a pair of slits 69a, 69b are formed in the upper part. Contacts 70a and 70b made of two plates are located within the slits 69a and 69b, respectively, and extend into the main body 68.

When these 60 and 61 are combined, the switch 60
The contacts 65a and 65b are the contacts 70 of the connector 61.
Electrical connection is established by being elastically press-fitted between the plates a and 70b. The insertion position is regulated by the protrusion 66 of the switch 60 coming into contact with the upper surface of the connector 61.

The anchor body 20 is manufactured, for example, by casting an aluminum alloy, and since a tapered pin is used as a mold for the hole 33 into which the connector 61 is inserted, the hole 33 is tapered. For this reason, the main body 68 of the connecting tool 61 is formed with a taper so as to become thinner toward the top, as is clear from the figure. This makes insertion into the hole 33 easy.

Although the embodiments of the present invention have been described above, the present invention is of course not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the switches 31, 60
and contacts 49a, 49b, 5 of connectors 35, 60
3a, 53b, 65a, 65b, 70a, 70b
is plate-shaped, but one may be rod-shaped and the other may be cylindrical hole-shaped.

[Effect of idea]

As described above, the structure of the anchor part of the drum brake according to the present invention makes it easy to attach/detach and replace the switch, and also facilitates the electrical connection to the cord. Furthermore, the seal configuration is also simplified.

[Brief explanation of drawings]

FIG. 1 is a plan view of the anchor structure of a drum brake according to an embodiment of the present invention, and FIG. 2 is a sectional view of the same.
Fig. 3 is a side view of the same, Fig. 4 is an enlarged perspective view of the same anchor structure before the switch and connector are connected,
Fig. 5 is an enlarged perspective view showing a modification of the switch and the connecting device, Fig. 6 is a plan view of the anchor structure of a conventional drum brake, Fig. 7 is a sectional view thereof, and Fig. 8 is a side view thereof. and FIG. 9 is a schematic side view of a wheel on a slope for explaining the operating principle and basic configuration behind the conventional example and the present invention. In addition, in the figure, 28... hole for installing a switch,
31, 60...Switch, 33...Connection tool attachment hole, 35, 61...Connection tool.

Claims (1)

[Claims for Utility Model Registration] A block fixed to a back plate fixed to a non-rotating part of the vehicle body, a hole provided through the block, and a block fitted into the hole so as to be movable at a predetermined distance. A movable member whose end side abuts the brake shoe, a second hole formed in the block in line with the hole, and a switch disposed in the second hole and switched by movement of the movable member. In the structure of the anchor part of the drum brake, a third hole is formed from the second hole to pass through the block and back plate and open to the outside, and a connecting part is provided to the switch so that a connecting tool can be attached and detached. An anchor part structure for a drum brake in which the connecting tool can be attached to and detached from the connecting part through the third hole.