JP6761275B2 - Vehicle drum brakes - Google Patents

Description

The present invention relates to a vehicle drum brake used for a traveling vehicle such as an automobile or a motorcycle, and more particularly to an anchor structure formed by attaching an anchor member to an anchor attachment portion provided on a back plate.

Conventionally, in a vehicle drum brake, a pair of brake shoes arranged to face the back plate, an anchor that abuts one end side of both brake shoes, and an expansion that expands the other end side of both brake shoes. Some of them are provided with a device, and the anchor is composed of an anchor member that abuts on one end side of the brake shoe and an anchor attachment portion that protrudes from the back plate and attaches the anchor member. In addition, while reducing the thickness of the back plate to reduce weight, in order to reinforce the anchor mounting part where stress is applied via the anchor member during braking, a reinforcing member is attached around the anchor mounting part. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 56-120832

However, in the above-mentioned Patent Document 1, although the strength of the anchor mounting portion can be secured, a reinforcing member to be mounted around the anchor mounting portion must be separately prepared, and it takes time and effort to mount the reinforcing member. The cost was high.

Therefore, an object of the present invention is to provide a back plate of a drum brake for a vehicle, which can secure the strength of an anchor mounting portion to which stress is applied during braking while suppressing the cost.

In order to achieve the above object, the vehicle drum brake of the present invention includes a pair of brake shoes arranged opposite to a back plate on which an axle insertion hole is formed, an anchor that abuts one end side of both brake shoes, and the above. In a vehicle drum brake provided with an expansion device that expands the other end side of both brake shoes, the anchor is an anchor member that abuts on one end side of the brake shoe and a protrusion from the back plate. The anchor mounting portion includes an anchor mounting portion for mounting the member, and the anchor mounting portion has a protruding portion protruding from the back plate in a cone shape and a seat surface for mounting the anchor member, and the seat surface has rivets. A hole is formed in the anchor member, and a rivet insertion hole is formed in the anchor member. By inserting the rivet through the rivet hole and the rivet insertion hole, the anchor member is fixed to the anchor mounting portion and the axle is fixed. On the outer surface of the protruding portion excluding the surface facing the insertion hole, a plurality of convex portions extending in the inside / outside direction of the back plate shall be continuously formed in a direction perpendicular to the inside / outside direction of the back plate . It is characterized by.

Further, it is preferable that the outer surface of each of the convex portions is formed of a part of a conical surface whose diameter gradually increases from the seat surface side to the back plate side. Further, it is preferable that the anchor mounting portion is formed symmetrically with respect to the radial center line of the back plate.

According to the vehicle drum brake of the present invention, stress is applied to the anchor mounting portion from the web via the anchor member during braking, but the anchor mounting portion is limited by forming a plurality of convex portions on the protruding portion. This stress can be dispersed in the space, the strength of the anchor mounting portion can be secured, and the breaking strength and durability of the back plate can be improved. Further, since the anchor mounting portion can be reinforced without mounting a separate member, the cost can be reduced.

Further, by forming the outer surface of each convex portion with a part of a conical surface whose diameter gradually increases from the seat surface side to the back plate side, the stress applied to the anchor mounting portion can be satisfactorily dispersed. .. Further, by forming the anchor mounting portion symmetrically with respect to the center line in the radial direction of the back plate, the stress applied to the anchor mounting portion can be evenly dispersed.

It is a front view of the back plate which shows the 1st Embodiment example of this invention. FIG. 2 is a sectional view taken along line II-II of FIG. It is a perspective view of the back plate which shows the 1st Embodiment example of this invention. It is also a front view of the drum brake. It is a VV cross-sectional view of FIG. It is a front view of the back plate which shows the 2nd Embodiment example of this invention. FIG. 6 is a sectional view taken along line VII-VII of FIG. It is a perspective view of the back plate which shows the 2nd Embodiment example of this invention.

1 to 5 are a leading trading type drum brake showing an example of the first embodiment of the present invention. The drum brake 1 is a pair of bow-shaped brakes inside a back plate 2 fixed to a vehicle body. The shoes 3 and 3 are housed so as to be expandable and contractible. Each brake shoe 3 has a web 3a whose intermediate portion is held by the shoe hold pin 4 and the shoe hold spring 5 on the back plate 2, and an arcuate rim 3b attached orthogonally to the outer surface of the web 3a. It is composed of a lining 3c attached to the outer peripheral surface of the rim 3b. One end of the web 3a is supported by the anchor 7, the other end is supported by the wheel cylinder 6 (expansion device of the present invention), and the back plate side surface of the rim 3b is formed on the back plate 2. It is supported on the ledge surface 8.

Return springs 9 and 10 are stretched between both ends of the webs 3a and 3a, and the brake shoes 3 and 3 are constantly urged in the radial direction by these return springs 9 and 10, and further, the return on the wheel cylinder side. A braking gap automatic adjusting device 11 is arranged at the inner position of the spring 9. Further, between the back plate 2 and the web 3a of one brake shoe 3, a parking lever 12 is pivotally supported at one end of the web 3a at the base end and is arranged in parallel with the back plate 2 and the web 3a. ing. Further, one end of the wire cable 13 is connected to the tip of the parking lever 12.

The back plate 2 has an axle insertion hole 14 formed in the center, and a positioning hole 15 for a wheel cylinder is formed on the upper side of the axle insertion hole 14 in FIG. 1. An anchor mounting portion 16 is formed on the lower side of the axle insertion hole 14 by projecting the plate material of the back plate 2 inward in a substantially frustum shape.

The anchor 7 is formed of the anchor mounting portion 16 and an anchor member 17 that abuts on one end side of the brake shoes 3 and 3. The anchor member 17 projects toward the one end side of the web 3a, 3a and the anchor block 17a that abuts on one end surface of the web 3a, 3a, and also hits the anti-back plate side of one end of the web 3a, 3a during braking. It is composed of an anchor plate 17b that contacts and presses one end portion toward the back plate side.

The anchor mounting portion 16 has a protruding portion 16a protruding from the back plate 2 and a seat surface 16b for mounting the anchor block 17a and the anchor plate 17b, and the seat surface 16b is formed parallel to the back plate 2. ing. Five convex portions 16c extending in the inward and outward directions of the back plate are continuously formed on the outer surface of the raised portion 16a excluding the surface facing the axle insertion hole 14, and the outer surface of each convex portion 16c is a seat. It is formed by a part of a conical surface whose diameter gradually increases from the surface side to the back plate side. Further, rivet holes 16d and 16d are bored in the seat surface 16b. Further, the anchor mounting portion 16 is formed symmetrically with respect to the center line L1 in the radial direction of the back plate 2.

Rivet insertion holes are formed in the anchor block 17a and the anchor plate 17b, respectively, and rivets extend over the rivet holes 16d and 16d of the anchor mounting portion 16 and the insertion holes provided in the anchor block 17a and the anchor plate 17b. By inserting and caulking the 18 and 18, respectively, the anchor block 17a and the anchor plate 17b are fixed to the seat surface 16b, and the anchor 7 is formed.

In the above-mentioned drum brake 1, the piston 6a is operated by supplying the hydraulic pressure generated in the hydraulic master cylinder by the driver's braking operation to the wheel cylinder 6, and both brake shoes 3 and 3 serve as fulcrums of the anchor 7. The outer peripheral linings 3c and 3c are slidably contacted with the inner peripheral surface of the brake drum to perform a hydraulic braking action. Further, when the parking lever 12 is rotated by the towing of the wire cable 13, the brake shoes 3 and 3 expand with the anchor 7 as a fulcrum, and the linings 3c and 3c come into contact with the inner peripheral surface of the brake drum. A mechanical braking action as a parking brake is performed.

The anchor mounting portion 16 that receives braking torque via the anchor block 17a and the anchor plate 17b during braking is limited because five convex portions 16c extending in and out of the back plate are continuously formed. The stress applied to the anchor mounting portion 16 can be dispersed in the space, and the strength of the anchor mounting portion 16 can be secured. Further, this can improve the breaking strength and durability of the back plate 2. Further, since the outer surface of each convex portion 16c is formed by a part of a conical surface whose diameter gradually increases from the seat surface side to the back plate side, the stress applied to the anchor mounting portion 16 is satisfactorily dispersed. Can be made to. Further, since the anchor mounting portion 16 is formed symmetrically with respect to the center line L1 in the radial direction of the back plate 2, the stress applied to the anchor mounting portion 16 can be evenly distributed to the left and right with respect to the center line L1. it can.

6 to 8 show a second embodiment of the present invention, and the same reference numerals are given to those showing the same components as those of the first embodiment, and detailed description thereof will be omitted. ..

In the anchor mounting portion 19 of the present embodiment, 11 convex portions 19c extending in the inward and outward directions of the back plate are continuously formed on the outer surface of the protruding portion 19a excluding the surface facing the axle insertion hole 14. The outer surface of the convex portion 19c is formed by a part of a conical surface whose diameter gradually increases from the seat surface side to the back plate side. Further, rivet holes 19d and 19d are bored in the seat surface 19b, and the rivets 18 and 18 are inserted through the rivet holes 19d and 19d and the insertion holes provided in the anchor block 17a and the anchor plate 17b. By caulking, the anchor block 17a and the anchor plate 17b are fixed to the seat surface 19b. Further, the anchor mounting portion 19 is formed symmetrically with respect to the center line L1 in the radial direction of the back plate 2.

The present invention is not limited to the above-described embodiment, and the number and shape of the convex portions provided on the anchor mounting portion are arbitrary. Further, the anchor member is not limited to the one in which the anchor block and the anchor plate are separate as in each of the above-described examples, but may be integrally formed. Further, if a space can be secured, a convex portion can be provided on the surface of the protruding portion facing the axle insertion hole. Further, the structure of the back plate excluding the anchor mounting portion is not limited to each of the above-described examples, and any structure may be used.

1 ... Drum brake, 2 ... Back plate, 3 ... Brake shoe, 3a ... Web, 3b ... Rim, 3c ... Lining, 4 ... Shoe hold pin, 5 ... Shoe hold spring, 6 ... Wheel cylinder, 6a ... Piston, 7 ... Anchor, 8 ... Ledge surface, 9, 10 ... Return spring, 11 ... Braking gap automatic adjustment device, 12 ... Parking lever, 13 ... Wire cable, 14 ... Axle insertion hole, 15 ... Positioning hole, 16 ... Anchor mounting part, 16a ... raised portion, 16b ... seat surface, 16c ... convex portion, 16d ... rivet hole, 17 ... anchor member, 17a ... anchor block, 17b ... anchor plate, 18 ... rivet, 19 ... anchor mounting portion, 19a ... raised portion. Part, 19b ... Seat surface, 19c ... Convex part, 19d ... Rivet hole

Claims (3)

A pair of brake shoes arranged to face the back plate on which the axle insertion hole is formed, an anchor that abuts one end side of both brake shoes, and an expansion device that expands the other end side of both brake shoes. In the equipped vehicle drum brake
The anchor includes an anchor member that abuts on one end side of the brake shoe, and an anchor attachment portion that protrudes from the back plate and attaches the anchor member.
The anchor mounting portion has a protruding portion protruding from the back plate in a frustum shape and a seating surface for mounting the anchor member.
A rivet hole is formed in the seat surface, and a rivet insertion hole is formed in the anchor member. By inserting the rivet through the rivet hole and the rivet insertion hole, the anchor member becomes the anchor attachment portion. Fixed to
On the outer surface of the protruding portion excluding the surface facing the axle insertion hole, a plurality of convex portions extending in the inside / outside direction of the back plate are continuously formed in a direction perpendicular to the inside / outside direction of the back plate. Drum brakes for vehicles characterized by being. The vehicle drum brake according to claim 1, wherein the outer surface of each of the convex portions is formed of a part of a conical surface whose diameter gradually increases from the seat surface side to the back plate side. The vehicle drum brake according to claim 1 or 2, wherein the anchor mounting portion is formed symmetrically with respect to a center line in the radial direction of the back plate.

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