JPH0356655Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a brake shoe holding device in a drum brake.

(Prior art) As a conventional brake shoe hold device, for example, the device shown in Figs.
15317) is known.

In the figure, 1 is a back plate connected to a fixed member, and 2 is a brake shoe that is slidable with respect to the back plate 1. The brake shoe 2 is formed by integrating a web 3 and a rim 4 into a T-shaped cross section by welding or the like, and a lining 5 is fixed to the outer periphery of the rim 4.

Reference numeral 6 denotes a leaf spring, and this leaf spring 6 is bent at an intermediate portion 6a and formed into a substantially U-shape consisting of an upper piece 6b and a lower piece 6c. This upper piece 6b is formed with a notch 6d whose tip end is open, and this notch 6d
A spherical recess 6e is recessed deep inside. The lower piece 6c is also provided with a notch 6f having approximately the same shape as the notch 6d of the upper piece 6b.

7 is a pin, and one end of this pin 7 is formed with a large-diameter hemispherical enlarged portion 7a, and the other end is formed with a small-diameter hemispherical enlarged portion 7b.

(Problems to be Solved by the Invention) When the conventional brake shoe 2 described above operates, the pin 7 tilts and the leaf spring 6 moves along with the pin 7.

Therefore, as is clear from FIG. 5, when the brake shoe 2 expands, a force in the direction of arrow A acts on the left side of the depression 6e, and when the brake shoe 2 returns, a force acts on the right side of the depression 6e. do. Since the left and right sides of the notch 6d of the upper piece 6b are divided, only the left side receives the force when the brake shoe 2 moves forward, and only the right side supports the acting force when the brake shoe 2 moves backward.

This type of brake is frequently used, and as the lining 5 wears and the movement of the brake shoe 2 increases, the stroke amplitude of the leaf spring 6 increases and the mounting load also increases. Furthermore, when the temperature inside the brake becomes high, the leaf spring 6 tends to deteriorate, so there is a problem that it cannot be supported by one piece alone, resulting in sagging or the pin 7 coming off.

(Means for solving the problem) In order to solve the above-mentioned problem, in the present invention, a leaf spring bent into a substantially U-shape is placed on the brake shoe, and the enlarged part of one end of the pin is bent. In a brake shoe holding device, the brake shoe is engaged with a back plate, and the enlarged portion at the other end is engaged with the upper piece of a leaf spring to urge the brake shoe to come into pressure contact with the back plate. , a step with a lower height on the bent side is provided on the upper piece of the leaf spring, a spherical recess corresponding to the hemispherical enlarged part of the pin is provided in this lower part, and the shaft portion of the pin passes through the center of this recess. A through-hole is formed in the high part, and a through-hole larger than the outer diameter of the hemispherical enlarged part is formed in the high part, and a passage is provided between the two holes through which the shaft part of the pin can move. Configure the show's hold device.

(Function) As described above, according to the present invention, since the free ends of the upper pieces of the leaf springs are connected, the acting force from the pin is absorbed in any case of reciprocating movement of the brake shoe. It is held by the pieces on both sides of the through hole. Therefore, the leaf spring does not become loose or the pin comes off, and reliability is high over a long period of time.

Furthermore, since the engaging portion between the pin and the leaf spring is spherical, positioning around the axis of the pin is not necessary when attaching and detaching the leaf spring, which facilitates assembly of the device.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. In the figure, the same reference numerals as those mentioned above indicate equivalent parts. That is, 1 is a back plate, 3 is a web of the brake shoe 2 (see FIGS. 4 and 5), 7 is a pin, and 7a and 7b are hemispherical enlarged portions.

In this embodiment, the middle part of a strip-like leaf spring material is bent into a substantially U-shape to form a bent part 8a, and a step 8g with a lower height on the bent part 8a side is formed on the upper piece 8b. A spherical recess 8e corresponding to the hemispherical enlarged portion 7b of the pin 7 is provided in this low height portion, and a through hole 8h through which the shaft portion of the pin 7 passes is provided in the center of the spherical recess 8e. , a through hole 8i larger than the outer diameter of the hemispherical enlarged part 7b is formed in the high part of the upper piece 8b.
A pin 7 is formed between the two holes 8h and 8i.
The leaf spring 8 is constructed by providing a passage 8j through which the shaft portion can move.

In addition, if the tongue piece 8k is formed by bending the end of the upper piece 8b while connected to the upper piece 8b as shown in the figure, without removing the material from the through holes 8h and 8i. During assembly, the tongue piece 8k elastically deforms and allows the passage of the enlarged part 7b of the pin 7, but after passing, it restores itself as shown in the figure by its own elastic force, so unless the tongue piece 8k is forcibly pried up. Pin 7 will never come off again.

Also, the opening sides of the leaf springs 8 are bent in the direction toward each other, and the gap C at the overlapping part and the upper piece 8b and the tongue piece 8 are formed.
The gap S between the plate surfaces of k is made narrower than the plate thickness, and the lateral height is made lower than the height of the bent portion 8a.
For example, if the protrusions 8l are provided, the leaf springs 8 will not become entangled with each other, so it will be easy to align the leaf springs 8, and automatic feeding by a parts feeder will become possible.

Next, a procedure for assembling the leaf spring 8 formed as described above will be explained. That is, in order to assemble the leaf spring 8, the hemispherical enlarged portion 7b of the pin 7 is inserted through the back plate 1, the web 3 of the brake shoe 2, and the lower piece 8c of the leaf spring 8 in this order.
After bending b to make the enlarged portion 7b protrude from the through hole 8i, the bent portion 8a of the leaf spring 8 may be pushed. At this time, there is no need to determine the directionality of the pin 7 around its axis since its engaging portion is spherical.

(Effects of the invention) As described above, according to the invention, since the free end of the upper piece 8b of the leaf spring 8 is connected, the pin can be fixed in any case of reciprocating movement of the brake shoe 2. The acting force from 7 is received by both end pieces of the through hole 8h. Therefore, the plate spring 8 does not get bent or the pin 7 comes off, and the reliability is improved over a long period of time.

Furthermore, since the engaging portion between the pin 7 and the leaf spring 8 is spherical, positioning around the axis of the pin 7 is not necessary when attaching and detaching, so that the assembly work of the device is facilitated.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a leaf spring according to the present invention, Fig. 2 is a side sectional view showing the assembled state of the device of the present invention, Fig. 3 is a perspective view of a conventional leaf spring, and Fig. 4 is a diagram of the leaf spring. FIG. 5 is a front sectional view showing the assembled state, and is an explanatory view when the brake shoe is in operation. 1... Back plate, 2... Brake shoe, 3... Web, 4... Rim, 5... Lining, 6... Conventional leaf spring, 7... Pin, 7a, 7
b... Hemispherical ampullae, 8... Leaf spring of the present invention,
8a...bent part, 8b...upper piece, 8c...lower piece,
8e... Spherical depression, 8g... Step, 8h... Through hole, 8i... Through hole, 8j... Passage.

Claims (1)

[Scope of utility model registration request] A leaf spring bent into a substantially U-shape is placed on the brake shoe, and the enlarged portion at one end of the pin is engaged with the back plate, while the enlarged portion at the other end is engaged with the upper piece of the leaf spring. In a brake shoe holding device that urges the brake shoe to come into pressure contact with the back plate, a step with a lower height on the bending side is provided on the upper piece of the leaf spring, and this lower height A spherical recess corresponding to the hemispherical enlarged portion of the pin is formed in the portion, a through hole through which the shaft portion of the pin passes through the center of this recess, and a through hole larger than the outer diameter of the hemispherical enlarged portion is formed in the higher portion. A brake shoe holding device, characterized in that a hole is formed, and a passage is provided between the two holes, through which a shaft portion of a pin can move.