JPS6039544Y2 - anti-rattle spring - Google Patents

Description

[Detailed description of the invention] This invention is based on an anti-ruddle spring that prevents the strut from ruddling, which is installed between one of a pair of brake shoes and a parking lever that is pivotally connected to the other brake shoe. Regarding.

A drum-type parking brake generally has a strut installed between one of a pair of brake shoes and a parking lever pivotally connected to the other brake shoe, and the parking lever is rotated by a parking cable connected to the tip of the strut. When the drum is moved, the pair of brake shoes are expanded and brought into sliding contact with the inner circumferential surface of the drum.

This strut is normally made of a rectangular parallelepiped bar with a wide width in the left and right direction. Alternatively, the parking lever is fitted.

However, since play is unavoidable between the strut and the web fitted into the recess, ruddling occurs around the axis of the strut and in the axial direction when the brake vibrates.

Therefore, conventionally, a spring is installed between one end of the strut and the brake shoe or parking lever so as to apply a pressing force in the axial direction of the strut to prevent the strut from ruddling. Ta.

However, it has been found that in duo-servo type parking brakes and the like, the following problems occur due to the pressing force caused by the action of the spring.

In other words, in the duo-servo type parking brake, one end of the pair of brake shoes is brought into contact with an anchor pin fixed to the backing plate, but the other ends are only connected to each other by a connecting member, and do not touch the backing plate. is in a state where it can move freely, so the pair of brake shoes are easily rotated around the anchor pin based on the pressing force of the anti-ladle spring mentioned above, and this rotation occurs even when the brakes are released. It has become clear that the brake shoe remains in sliding contact with the brake drum, causing so-called dragging.

More specifically, the pressing force from the anti-ladle spring described above is transmitted directly to the first brake shoe to which the parking lever is pivotally connected via the parking cable, and directly to the other second brake shoe.

The force transmitted to these brake shoes is then received by the shoe return spring.

However, on the first brake shoe side, the pressing force is also shared by the cable connected to the tip of the parking lever, so each of the pair of brake shoes tends to rotate outward from each other around the anchor pin. A difference occurs in the moment, and as a result, the pair of shoes connected by the connecting member rotates around the anchor pin toward the second brake shoe, and the second brake shoe comes into sliding contact with the brake drum. It's put away.

In view of the above circumstances, the purpose of this invention is to provide an anti-ladle spring that prevents strut ruddling without applying a pressing force in the strut axial direction between the strut and the brake shoe or parking lever. The gist of this is that one end of a strut is mounted between one of a pair of brake shoes and a parking lever pivotally connected to the other brake shoe, and a first engaging portion that elastically clamps one end of the strut from above and below an anti-ladle spring that is attached between the shoe or the parking lever and prevents the strut from ruddling; The second engaging part extends in the opposite direction to the joining part and elastically clamps the one brake shoe or parking lever from the left and right sides.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking as an example a case in which an anti-ladle spring is installed between one end of a strut and a brake shoe.

In FIG. 1, 10 is a backing plate, and on this backing plate 10 are a pair of brake shoes 2,
3 is attached with a constant pressing force applied by shoe hold down springs 4 and 5.

Further fixed on the backing plate 10 are a wheel cylinder 5 which acts to spread the brake shoes 2.3 using braking fluid pressure, and an anchor pin 6 which receives the drag force of the brake shoes 2 or 3 during brake operation.

This anchor pin 6 is engaged with one end of shoe return springs 8, 9 for returning the brake shoes 2.3 to their original positions.

21 is also a shoe return spring.

The brake shoes 2 and 3 have arcuate webs 2at3a,
a rim 2b fixed at right angles to the outer edge of the web 2at3a;
3b and a lining 2ct3c fixed to the outer surface of the rims 2b and 3b.

The upper ends of the webs 2a, 3a are brought into contact with the anchor pin 6, and the lower ends are connected to each other by a length-adjustable connecting member 7.

A parking lever 11 is pivotally mounted near the upper end of the web 2a of the brake shoe 2.

Notches 2d and 3d are formed in portions of the parking lever 11 and the brake shoe 3 that face each other in the vicinity of the wheel cylinder 5.
The strut is passed between the d and the strut.

Rectangular openings are formed at both ends of the strut 12, and the parking lever 11 and the webs 3a and 3a of the brake shoe 3 are fitted into the openings.

A parking cable (not shown) is connected to the tip 11b of the parking lever 11, and when the cable is pulled and the parking lever 11 is rotated counterclockwise, the strut 12 moves to the right. The brake shoes 3 are expanded by the force, and the brake shoes 2 are expanded by the reaction force, and the respective linings 2c are expanded.
, 3c come into sliding contact with the inner surface of the brake drum 1 (only the position is shown by the two-dot chain line), and the brake is put into action.

An anti-ladle spring 30 constructed according to the present invention is installed between one end of the strut 12 and the web 3a.

This anti-riddle spring 30 is connected to a fenestration 1 provided at one end of the strut 12, as shown in FIGS. 2 to 4.
A quadrilateral connecting part 31 is inserted into the fenestration 2a and contacts the bottom surface of the fenestration.

This connecting portion 31 has a height and a width that are different from those of the slats 12, respectively.
and the thickness of the web 3a.

A pair of arms 32 are integrally formed on the connecting portion 31 and extend from both upper and lower ends toward the strut 12 to elastically clamp the strut 12 from both upper and lower surfaces, and constitute a first engaging portion 33. There is.

Similarly, struts 1 are connected from both left and right ends of the connecting portion 31.
A pair of arms 3 extend toward the web 3a along the fenestrated side surfaces of the two ends and elastically sandwich the web 3a from both left and right sides.
4 are integrally formed and constitute the second engaging portion 35.

At the tips of these arms 32 and 34, struts 1 are attached.
A head 32a1 widened in the width direction of the web 2 and a head 34a widened vertically along the web are provided, respectively, so that rotation of the strut 12 around its axis can be effectively prevented. It is being done.

The above-mentioned strut 12 equipped with the anti-ladle spring having such a structure has a first engaging portion 3 formed integrally with the strut 12.
Since the strut 12 and the web 3a are clamped and restrained by the second engaging portion 2 and the second engaging portion 35, and therefore their relative rotation is suppressed, ruddling around the axis is effectively prevented.

In addition, the frictional force generated by the elastic force of the engaging portions 32, 34 suppresses displacement and prevents ruddling in the axial direction.

Therefore, unlike when a conventional anti-ladle spring is installed, a pressing force in the axial direction is not generated, so that the lining 3c does not come into contact with the brake drum 1 and cause a dragging phenomenon.

The anti-ladle spring 30 of this embodiment is obtained by bending a substantially cross-shaped plate spring material 40 that can be easily formed by punching or the like, as shown in FIG. ,
Therefore, it has the advantage of low manufacturing cost.

In addition, the anti-ladle spring may be made by bending a plate spring material 50 having the shape shown in FIG. The object of the present invention can be achieved even if the first and second engaging portions that are clamped are integrally formed.

Furthermore, it goes without saying that the anti-ladle spring can be attached between the strut 12 and the parking lever 11.

As detailed above, this invention uses the anti-ladle spring installed between the strut and the brake shoe or parking lever with the first and second engagements that elastically clamp the strut and the brake shoe or parking lever, respectively. This enables effective ruddling around the strut axis and in the axial direction without generating pressing force in the strut axial direction, which causes brake drag. This has the effect of preventing

[Brief explanation of the drawing]

Figure 1 is a front view of a drum brake including an anti-ladle spring that is an embodiment of the present invention, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 shows the installation of the anti-ladle spring in Figure 1. FIG. 4 is a perspective view of the anti-ladle spring shown in FIGS. 1 to 3, FIG. 5 is a developed view of the anti-ladle spring shown in FIG. 4, and FIG. The figure is a developed view of an anti-ladle spring that is another embodiment of the present invention. 1... Brake drum, 2, 3... Brake shoe, 2at 3a... Web, 6
...Anchor pin, 7...Connection member, 8
, 9...Shoe return spring, 10...
... Backing plate, 11 ... Parking lever, 12 ... Strut, 30 ...
...Anti-ladle spring, 31...Connection part, 32.34...Arm, 32 a, 3
4 a... Head, 33... First engaging part, 35... Second engaging part.

Claims (1)

[Claims for Utility Model Registration] One end of a strut installed between one of a pair of brake shoes and a parking lever pivotally connected to the other brake shoe, and an anti-ladle spring installed between the strut and the first engaging part that elastically clamps one end of the strut from above and below; An anti-ladle spring characterized in that it is integrally provided with a second engaging portion that extends in the opposite direction and elastically clamps the one brake shoe or parking lever from left and right.