JPS604843Y2 - Integral type drum brake - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an integral drum brake constructed integrally with a trailing arm suspension system.

In order to reduce the weight of the vehicle body, in suspension systems in which the trailing arm is formed into a box shape from a steel plate, the anchor member that engages and supports one end of the brake shoe and supports the braking torque reaction force is attached to the trailing arm. Fixed directly to the arm, 1
Braking torque reaction force does not act on the back plate that guides the pair of brake shoes.

The present invention proposes an integral type drum brake in which the anchor member has a small number of parts, is easy to install, is lightweight, and has sufficient strength.

To explain the configuration of the present invention based on an embodiment, first, as shown in FIG. The base end of the trailing arm 11 is fixed, and the axle 5 is provided at the tip to support a wheel.

The trailing arm 11 is a plate-shaped plate 1 punched from a steel plate.
It is constructed in a box shape by butting and joining a pair of divided bodies,
A shock absorber 9 is coupled between the mounting pin 8 fixed to the intermediate portion of the trailing arm 11 and the vehicle body, and the shock absorber 9 is connected between the mounting pin 8 fixed to the intermediate portion of the trailing arm 11 and the vehicle body.
1 swings as the torsion bar 12 twists, and the shock absorber 9 cushions the impact on the vehicle body.

The axle 5 is fixed to the trailing arm 11, and the trailing arm 11 has a flat wall surrounding the axle 5, and a circular back plate 13 that covers the open end of the brake drum is provided on the wall. It is fixed concentrically with the axle 5.

The hydraulic cylinder device 1 is fixed to the left side of the back plate 13, while the anchor member 10 is supported on the right side by a method described later.

The left end of the web 6 of the pair of upper and lower brake shoes 20 is engaged with the groove at the end of the pair of pistons fitted in the hydraulic cylinder device 1, and the arcuate notch provided at the right end of the web 6 is engaged with the anchor member 10.

This engaged state is maintained by the spring 3 stretched between the webs 6 and another spring (not shown).

The brake shoe 20 is formed by bonding a lining 7 to the outer surface of a rim 4 made of a band plate curved in an arc shape, and a web 6 made of a crescent-shaped flat plate to the inner surface. The part is lightly abutted against the back plate 13 by a known guide device (not shown) so that it can slide along the back plate 13.

As shown in FIG. 2, the anchor member 10 is constructed as a cup-shaped body by drawing a relatively thick steel plate using a press.

The arc-shaped notch provided at the end of the web 6 of the brake shoe mentioned above is brought into contact with the outer circumferential surface of the anchor member 10 made of this cup-shaped body, so that the web 6 does not come off the outer circumferential surface. In addition, the open end of the anchor member 10 is bent radially outward to form a flange 10a integrally.

The bottom 10b of the anchor member 10 has a trailing arm 11
A bolt hole 19 is provided, and a small diameter shaft portion 10C is provided that extends in the axial direction from the bottom portion 10b and is continuous with the bolt hole 19.

The shaft portion 10c is fitted into a hole 18 provided in the back plate 13.

A nut 17 is fixed in advance to the inner wall surface of the trailing arm 11 by welding or the like, and a bolt 14 is screwed into this screw hole through a hole 16 provided in the trailing arm 11.

That is, the anchor member 10 has the small diameter shaft portion 10c fitted into the hole 18 of the back plate 13 in advance, and then the back plate 13 is impacted against the outer wall surface of the trailing arm 11, so that the anchor member 10, which is made of a cup-shaped body, is released from the inside. Insert the bolt 14 through the seat plate 15 and the holes 19 and 16, and screw it into the nut 17 to fix it.

In this way, the anchor member 10 is positioned in the hole 18 of the back plate 13, and the tolerance of the position with respect to the nut 17 fixed to the trailing arm 11 is determined by the gap between the bolt hole 19 and the bolt 14, and the gap between the shaft portion 10c and the hole. This is resolved by the gap between 16 and 16.

In the drum brake configured as described above, when pressure fluid is supplied to the central chamber of the hydraulic cylinder device 1, the pair of pistons are pushed outward from each other, and the pair of brake shoes 20 are engaged with the anchor member 10. The mating left end portion is used as a fulcrum to spread out and press against the inner circumferential surface of a brake drum (not shown) to generate braking force.

The braking torque reaction force received by one brake shoe 20 is supported by the anchor member 10 and directly transmitted to the trailing arm 11, and does not act on the back plate 13.

Therefore, the back plate 13 is relatively thin because it only serves to guide the brake shoes 20, support the hydraulic cylinder device 1, and cover the open end to prevent dust from entering the inside of the brake drum. It can be constructed from steel plates, etc., and is useful for weight reduction.

In addition, the anchor member 10 has a diameter sufficient to swingably support one end of the web 6 facing each other, and a length from the back plate 13, and is hollow, so the weight is reduced. Furthermore, since the bottom portion 10b of the anchor member 10 is fixed to the trailing arm 11, the length of the bolt 14 for fixing can be shortened, which helps to reduce the weight.

Further, since no compressive force is generated in the cylindrical portion of the anchor member 10 due to the tightening force of the bolt 14, this is advantageous in terms of strength compared to the case where a sleeve is fixed as the anchor member with a bolt.

In the above-mentioned embodiment, the anchor member 10 is directly fixed by the bolt 14, but as shown in FIG. The same effect can be obtained by connecting the bolts 14 in advance, protruding the tip of the bolt 14 from the hole 16 of the trailing arm 11 into the anchor member 10, and tightening and fixing the bolt 14 with the nut 21.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the integral type drum brake according to the present invention installed on a trailing arm, Fig. 2 is a side sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a FIG. 4 is an enlarged view of the main part of the figure and a side sectional view similar to FIG. 2 according to a partially modified embodiment of the present invention. 1: hydraulic cylinder device, 6: web, 10: anchor member, 11: trailing arm, 14: bolt, 17: nut, 20 brake shoe, 21: nut.

Claims (1)

[Scope of utility model registration request] An anchor pin that engages and supports the opposing base end portions of the pair of brake shoes is constructed as a cup-shaped body, the bottom of the cup-shaped body abuts against the side surface of the trailing arm of the suspension device together with the back plate, and An integral type drum brake that is fixed with bolts.