JPS6325386Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mechanically actuated drum brake device equipped with a slideable actuator.

[Conventional technology]

Traditionally, mechanically actuated drum brake devices have used a so-called slideable type actuator, in which the actuator that opens a pair of brake shoes is slidably placed between the ends of the shoe webs of both brake shoes. However, in this actuator, the direction in which the brake wire that rotates the brake lever, which is pivoted at one end, is pulled is in a direction that deviates from the normal rotation plane of the brake lever due to the arrangement position of the parts. In some cases, the brake lever and actuator are tilted when the brake is applied, which may cause problems in the brake operation.

[Purpose of invention]

This idea was created in view of these circumstances.
Prevents the sliding type actuator from tilting,
An object of the present invention is to provide a mechanically actuated drum brake device that provides accurate brake operation.

[Structure of the idea]

In order to achieve the above object, the present invention arranges a pair of brake shoes on the inner surface of the back plate.
One end of the shoe web of each brake shoe is brought into contact with an anchor, and the other end of the brake lever extends outward from the back plate, and the brake lever is connected to a side plate that is erected on the inner surface of the back plate. A machine that engages with a slideable actuator that is pivotally supported on one end side, and performs a braking action by expanding both brake shoes by the rotation of the brake lever and the actuator that slides due to this rotation. In the actuated drum brake device, the actuator connects a pair of parallel side plates at a bridge portion, pivots the brake lever between the side plates on one end, and supports the lower surfaces of both side plates on the inner surface of the back plate. , on the other hand, engagement grooves are formed in the other end of the shoe web of one brake shoe disposed on the brake lever side and the other end of the shoe web of the other brake shoe, respectively, so that the action part of the brake lever and the other end of the actuator are provided with engagement grooves. A brake shoe engagement groove is provided in each of the brake shoe, and each brake shoe engagement groove of the brake lever and actuator is engaged with each brake shoe engagement groove, and the brake shoe engagement groove of the brake lever is engaged with each brake shoe engagement groove of the brake lever and the actuator. It is characterized in that the back surface of the action portion on the opposite side to the matching groove is supported in contact with the bridge portion of the side plate.

〔Example〕

Next, an embodiment of a mechanically actuated drum brake device according to the present invention will be described based on the drawings.

In the drum brake device 1, a pair of brake shoes 3, 3 are arranged on the inner surface side of a back plate 2, and one end of the brake shoes 3 on the same side is connected to each shoe web 3.
a, 3a are brought into contact with an anchor 4 fixed to the back plate 2, and the other end of each is engaged with an actuator 5 and an operating portion 7 of a brake lever 6 pivotally supported on the actuator 5, Both brake shoes 3, 3 are biased inwardly by two return springs 8, 8 stretched between respective shoe webs 3a, 3a, and a shoe hold down spring 9 is attached to the back plate 2. , 9, and is swingably locked by the hold down pins 10, 10.

The actuator 5 is of a sliding type that slides on the inner surface of the back plate 2 when the brake is applied, and gradually separates one end side of a pair of parallel side plates 11, 11 that are erected on the inner surface of the back plate 2. The upper part of the side with the maximum separation is connected in parallel by a bridge part 12, and the other ends of both side plates 11 and 11 are connected against each other, and both side plates 1 on one end side are connected in parallel.
The brake lever 6 is pivotally supported between 1 and 11 by a rotating shaft 13, and the other end of the abutting connection is provided with:
A brake shoe engagement groove 14 is formed.

The lower part of the other end of the side plates 11, 11 is provided with a brake lever 6 that passes through the hole 2a of the back plate 2.
An anti-floating arm 15 that is bent in the braking rotation direction (direction of arrow A in FIG. The contact portion 15a of the prevention arm 15 is brought into contact with the outer surface of the back plate 2, and the lower surface 1 of the side plate 11 is brought into contact with the outer surface of the back plate 2.
1a is supported on the inner surface of the back plate 2, and is erected between both brake shoes 3, 3.

The brake lever 6 is provided with a restraining piece 7a protruding in the direction of one brake shoe 3 on the brake lever 6 side at the distal end side of the acting part 7 disposed on the inner surface of the back plate 2. A brake shoe engagement groove 16 is formed in the lower part, and the force side arm part 17 extending on the opposite side of the action part 7 is passed through the hole 2b of the back plate 2 which is connected to the hole 2a.
It is arranged on the outer surface side of the back plate 2.

Brake shoes 3, 3 have each shoe web 3
Engagement grooves 18 and 19 are formed at the other end of a, and one brake shoe 3 on the brake lever 6 side engages the engagement groove 18 with the brake shoe engagement groove 16 of the brake lever 6. The upper surface of the brake lever 6 is locked to the restraining piece 7a, and
The upper part of the back surface 7b of the action part 7 on the opposite side to the brake shoe engagement groove 16 is connected to the bridge part 1 of the side plate 11.
It is supported in contact with 2.

Further, the other brake shoe 3 connects the engagement groove 19 of the shoe web 3a to the side plate 1 of the actuator 5.
Both brake shoes 3, 3 are engaged with the brake shoe engagement groove 14 formed in the brake lever 6 and the brake shoe engaging groove 14 formed in the brake lever 6, and are biased inwardly by the return springs 8, 8. 7a and the bridge portion 12 of the actuator 5 come into contact with each other to restrict diameter reduction.

Further, the actuator 5 and the brake lever 6 have respective brake shoe engagement grooves 14 and 16.
Shoe web 3a of each brake shoe 3
Since the actuator 5 and the brake lever 6 are fitted into the engagement grooves 18 and 19 so as to be deeply sandwiched between them, the actuator 5 and the brake lever 6 can be prevented from tilting during operation.

Next, the operation of the mechanically actuated drum brake device 1 configured as described above will be explained.

The force side arm 6a of the brake lever 6 extending toward the outer surface of the back plate 2 is moved in the braking direction (arrow A
direction), the action portion 7 of the brake lever 6 rotates counterclockwise, and one brake shoe 3 that engages with the lever 6 is pushed outward, and the reaction caused by this pushing is As the actuator 5 slides in the direction of arrow A by force, the other brake shoe 3 that engages with the actuator 5 is also pushed outward, and the brake action is performed by expanding both brake shoes 3, 3.

When the brake is applied, the rotation shaft 13 serving as the rotation fulcrum of the brake lever 6 moves between both brake shoes 3, 3, the brake lever 6, and the actuator 5.
Since it is located on one end side of the actuator 5 and is offset toward the back plate 2 side with respect to the pushing point where the brake lever 6 engages, when the brake lever 6 rotates, one brake shaft that engages with the lever 6 A force acts on the user 3 to levitate the shew web 3a in the counterclockwise direction in FIG.
A force that causes the shoe web 3a to float clockwise in FIG. The other brake shoe 3 includes a contact portion 15a of an anti-float arm 15 that contacts the outer surface of the back plate 2, a side plate 11 that is widely supported on the inner surface of the back plate 2,
Since the rotation couple of the actuator 5 is received by the lower surfaces 11a, 11a on one end side of the actuator 11, floating is prevented.

In addition, if the direction in which the brake wire (not shown) is pulled is away from the normal rotating surface of the brake lever 6, for example in the direction of arrow B or arrow C, the brake wire is pulled and the brake lever 6
When the actuator 5 is rotated, a force is generated to tilt the actuator 5, but the shoe webs 3a, 3a of both brake shoes 3, 3 and the brake shoe engagement grooves 14, 16 of the actuator 5 and brake lever 6 are Since the actuator 5 and the brake lever 6 pivotally supported by the actuator 5 are fitted into each other so as to be sandwiched by the side surfaces, the actuator 5 and the brake lever 6 are effectively prevented from tilting during operation by the brake shoes 3, 3.

Further, the actuator 5 can be slid stably by the side plates 11, 11 provided apart from each other.

Therefore, both brake shoes 3, 3 are pushed smoothly without inclination, so that uneven wear of the lining can be prevented and sufficient braking operation can be smoothly performed.

[Effect of idea]

As explained above, the present invention connects a pair of parallel side plates of an actuator at a bridge part, and pivots a brake lever between the side plates on one end side.
The lower surfaces of both side plates are supported on the inner surface of the back plate,
Engagement grooves are provided on the other ends of the shoe webs of both brake shoes and the actuator and brake lever so that the grooves engage with each other, and the rear surface of the action section on the opposite side of the brake shoe engagement groove of the brake lever is attached to the bridge section. Because it is supported in contact with the rear surface, even if the brake wire is pulled in a direction that deviates from the normal rotating surface of the brake lever, it effectively prevents the actuator and the brake lever from tilting during operation, ensuring smooth operation. Brake operation can be achieved.

[Brief explanation of the drawing]

The figures show an embodiment of a mechanically actuated drum brake device according to the present invention, in which Fig. 1 is a front view, Fig. 2 is a sectional view taken from the side shown in Fig. 1, and Fig. 3 is a sectional view taken from the side shown in Fig. 2. It is a diagram. 2...Back plate, 3...Brake shoe, 3a...Show web, 4...Anchor, 5...
...Actuator, 6...Brake lever, 7...
...Action portion, 11...Side plate, 11a...Bottom surface of side plate 11, 12...Bridge portion, 14, 16...Brake shoe engagement groove, 15...Floating prevention arm, 1
8, 19...Engagement groove.

Claims (1)

[Scope of utility model registration request] A pair of brake shoes are arranged on the inner surface of the back plate, one end of the shoe web of each brake shoe is brought into contact with the anchor, and the other end is connected to the action part of the brake lever extending outward from the back plate. , the brake lever is engaged with a slideable actuator pivotally supported on one end side of a side plate erected on the inner surface of the back plate, and the rotation of the brake lever and the actuator that slides due to this rotation. In a mechanically actuated drum brake device that performs a braking action by expanding both brake shoes, the actuator connects a pair of parallel side plates at a bridge portion,
The brake lever is pivotally supported between the side plates on one end side, and the lower surfaces of both side plates are supported on the inner surface of the back plate. An engagement groove is formed at the other end of the shoe web of the brake shoe, and a brake shoe engagement groove is provided at the operating portion of the brake lever and the other end of the actuator. , the brake lever and the actuator are engaged with each brake shoe engagement groove, and the back surface of the operating portion of the brake lever on the opposite side to the brake shoe engagement groove is supported in contact with the bridge portion of the side plate. A mechanically operated drum brake device featuring: