JPH0150774B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mounting structure for a drum brake.

In this kind of conventionally known mounting structure, a center hole of the back plate is fitted into a spindle that projects integrally from a mounting portion of a non-rotating body of the vehicle body, and a mounting surface around the center hole of the back plate is attached to a non-rotating body. The back plate mounting surface is fastened to the non-rotating body mounting surface using a plurality of fastening bolts, nuts, etc. Therefore, if the external shape of the mounting part of the non-rotating body required for the fastening is inevitably determined and it is difficult to reduce it, or if the external shape of the mounting part of the non-rotating body is to be made small,
There were problems in reducing weight and improving ease of assembly, such as having to increase the number of fastening bolts instead of reducing their diameter. In addition, in order to meet society's demand for fuel-efficient vehicles, there has been a trend toward smaller brake sizes in recent years, and the space for tightening with multiple fastening bolts, nuts, etc. is becoming increasingly restricted, and the design The reality is that this makes it difficult.

The present invention solves the above-mentioned problems by providing a means for preventing relative rotation between the mounting portion of the non-rotating body and the back plate, and a means for preventing axial movement of the back plate that protrudes through the center hole of the back plate. The back plate is attached to a spindle that is integrated with the non-rotating body, and the back plate is attached to the non-rotating body. One embodiment will be described in detail below with reference to the drawings. 1 is a non-rotating body of the vehicle body, 1a is a flange thereof, 1b is an integral spindle protruding from the center of the flange 1a, 2 is a back plate, the center hole 2a of which is fitted into the outer periphery of the base of the spindle 1b, Moreover, the mounting surface 2b is joined to the mounting surface 1c of the flange portion 1a. Reference numerals 3 and 4 designate a pair of brake shoe rims 3a and 4a facing each other, and rims 3a and 4a and shoe webs 3b and 4b are usually welded to form a T-shaped cross section, and linings 3c and 4c are provided around the outer peripheries of the rims 3a and 4a. are attached to each.
In addition, bent portions 3d and 4 bent toward the inside of the brake are provided on both sides of the substantially central portion in the circumferential direction of the rims 3a and 4a (only one side on the back plate 2 side is also acceptable).
d is formed, and bent portions 3d and 4d on one side thereof movably slide on the raised portions 2c and 2d of the back plate 2, respectively. 5 and 6 are wheel cylinders which are hydraulic pressure generators, and the shew webs 3b and 4b
The back plate 2 is placed between the left and right adjacent ends of the
It is usually fixed with bolts etc. The one ends 3e, 4e of the shew webs 3b, 4b are connected to the grooves 8a, 9a of the adjustment bolts 8, 9 which are screwed into the piston 7 (the piston on the cylinder 6 side is not shown), and the other end 3e.
f and 4f are fitted into grooves 11a and 10a provided in cylinder bodies 10 and 11, respectively.

Reference numerals 12 and 13 are return springs stretched between the shoe webs 3b and 4b, which pull the brake shoes 3 and 4 inward toward each other when the brake is not activated. Also, return springs 12, 13
Since the coil portions of the brake shoes 3 and 4 are located below the shoe webs 3b and 4b, that is, on the back plate 2 side, the brake shoes 3 and 4 have both left and right adjacent ends 3e and 3f of the show webs 3b and 4b, as shown in FIG. and 4
Respective grooves 8a, 11a and 9 where the edges of e and 4f abut
A moment is applied in the direction of the arrow using the bottom of a, 10a as a fulcrum, and the bent portion 3 of the shu rims 3a, 4a is constantly
d and 4d are the raised parts 2c and 2d of the back plate 2.
It is supported in contact with the top.

14 is a hub rotatably supported by the spindle 1b via bearings 15a, 15b;
A bottom portion 16a of a substantially bowl-shaped brake drum 16 and a tire wheel 17 are integrally fixed to the flange portion 14a with a plurality of hub bolts 18. The inner peripheral surface of the cylindrical portion 16b of the brake drum 16 surrounds the linings 3c, 4c with a desired gap.

The above-described assembly is an example of a well-known two-leading drum brake assembly.
The brake operation will be explained. When the driver steps on the pedal, hydraulic pressure is generated in the wheel cylinders 5 and 6.
The piston 7 (the piston on the cylinder 6 side is not shown) expands the brake shoes 3 and 4 against the return springs 12 and 13, respectively, and applies a lining 3c to the inner peripheral surface of the brake drum 16 rotating together with the wheels. , 4c are pressed against each other to brake them. The brake drum 16 and lining 3c generated at this time,
The frictional force between the cylinder bodies 10 and 4c supporting one end portions 3f and 4f of the shew webs 3b and 4b,
11, the mounting surface 2b of the back plate 2 is mounted and held on the flange portion 1a of the non-rotating body 1.

The present invention relates to the mounting structure of the back plate 2, and relates to the mounting surface 2 of the back plate 2.
b is provided with one or more protrusions that protrude toward the flange portion 1a of the non-rotating body 1. In other words, in the example shown in FIG. It is tightly fitted into the fitting hole 1A provided in the flange portion 1a, and
In the example shown in FIG. 6, a protrusion 2B having a straight portion is formed on the mounting surface 2b of the back plate 2 in the same way as in the previous example, and the straight portion of the protrusion 2B is formed on the corresponding flange portion 1.
a is in contact with the non-circular outer edge 1B of the spindle 1b, and serves as a means for preventing rotation of the back plate 2. As shown in FIG.
An annular groove 1E is formed on the outer periphery at intervals equal to or less than the plate thickness of
is formed in the annular groove 1E, and a substantially U-shaped groove made of an elastic material is formed in the annular groove 1E.
The intermediate curved portion of the letter-shaped snap spring 19 is elastically mounted to serve as a means for preventing the back plate 2 from moving in the axial direction.

Furthermore, the above-mentioned snap spring 19 is not limited to an elastic material; for example, a substantially U-shaped steel material may be fitted into the groove 1E and then gripped by narrowing the opening side. As is clear from FIG. 4, one end surface of the annular groove 1E is connected to the back plate 2.
It is clear that if the snap ring is tapered to narrow toward the snap ring and is set so that the inside of the curved portion does not come into contact with the bottom of the annular groove 1E when the snap ring is fitted, the mounting state will be stabilized. Furthermore, the first
Although the figure shows both a circular protrusion 2A and a protrusion 2B having a straight portion, which are rotation preventing means, it is of course possible to use only one of the protrusions.

As described above, the present invention not only provides means for preventing rotation of the back plate 2 with a simple structure, but also functions as a positioning means for the back plate 2, which is conventionally generally used. Since it is possible to reduce or eliminate the number of fastening bolts, nuts, etc. and to reduce the external size of the flange portion 1a, it is possible to reduce weight, which is a major element of fuel-efficient vehicles, and to connect brake pipes, etc., and to bleed air. In addition, there is no need for space for fastening bolts and nut mounting sockets, and the design layout is extremely easy, making it easy to downsize the brake. or,
When the snap spring 19 is made of an elastic material, the back plate 2 can be attached and detached with a single touch, and the operation is simple.Furthermore, it can be applied to all types of drum brakes, and has a wide range of applications, which has great practical effects. There is something. It should be noted that the present invention is by no means limited to the above-mentioned embodiments; for example, the bottom side and the opening side of the snap spring 19 may be extended above the shoe webs 3b, 4b to prevent excessive lifting of the brake shoes 3, 4. Alternatively, the snap spring 19 may be rotated by 90 degrees as shown in FIG. 13 back plate 2
Press lightly towards the side to release spring 1.
The scope of its use is extremely wide, such as providing a vibration-proofing effect for the cylinder bodies 10 and 13, and making the extension part embrace the outside of the cylinder bodies 10 and 11 so that it can be used for mounting the wheel cylinders 5 and 6.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a front view of the brake assembly partially cut away, FIG. 2 is a cross-sectional view taken from FIG. FIG. 4 is a detailed view of the Y section in FIG. 2, and FIGS. 5 and 6 are cross-sectional views showing embodiments of the rotation prevention means. 1...Non-rotating body, 1a...Flange portion, 1b...
...spindle, 1A...fitting hole, 1B...outer edge,
1E...Annular groove, 2...Back plate, 2a...
...Central hole, 2b...Mounting surface, 2A, 2B...Protrusion, 3, 4...Brake shoe, 3a, 4a...
Shurim, 3b, 4b...Shyuweb, 5,
6...Wheel cylinder, 16...Brake drum, 19...Snat spring.

Claims (1)

[Claims] 1 Relative rotation prevention means 1A, 2A, or 1 is installed between the mounting portion of the non-rotating body 1 of the vehicle body and the back plate 2.
A drum brake characterized in that the axial movement prevention means 19 of the back plate 2 is locked to a spindle 1b integrated with a non-rotating body 1 that projects through a central hole 2a of the back plate 2.