JPH064113Y2 - Wheel cylinder with adjusting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a wheel cylinder with an adjusting device used in a wheel brake device of a vehicle or the like.

[Conventional technology and its problems]

For example, according to the device described in Japanese Patent Publication No. 47-33827,
One end of the strip plate member arranged outside the cylinder body is connected to the piston head attached to the piston via a pin, and a notch is formed at the other end, which is attached to one end of the adjustment lever. Pin is engaged. A spring is stretched between it and these pins. However, the action position of the biasing force of the spring is bad, and an eccentric load is applied to the adjusting lever, which causes problems such as reverse rotation of the ratchet wheel.

[Problems to be solved by the invention]

The present invention has been made in view of the above problems, and an object of the present invention is to provide a wheel cylinder with an adjusting device that allows the biasing force of a spring to be correct and simplifies the positioning structure.

[Means for solving problems]

The above-mentioned object is arranged between the cylinder body having the cylinder hole, the piston slidably inserted into the cylinder hole to define the pressure chamber, and the piston and the brake friction material, and the length can be adjusted. A pair of screw members screwed to each other, a ratchet wheel formed on one screw member, a plate member that is movable along the cylinder body outside the cylinder body, and interlocks with the piston, A plate-shaped adjusting lever having a claw portion that is rotatably supported outside the cylinder body and that can engage with the ratchet in one direction, and a spring that urges the adjusting lever and the plate member in a direction in which they abut each other. And a U-shaped hook portion formed on one end side of the spring and engaging with the adjustment lever, the hook portion of the adjustment lever engages. A first bent portion that substantially conforms to the shape of the hook portion is formed, and one side surface side of the spring is positioned by a flat portion formed on the plate member, and the other side surface side is the first bent portion. This is achieved by a wheel cylinder with an adjusting device, which is positioned by bringing the side surface of the hook portion into contact with the end surface of the second bent portion extending from.

[Action]

The spring is a flat part formed on one side surface side of the plate member, and the other side surface side is positioned by bringing the hook side surface into contact with the end surface of the second bent portion extending from the first bent portion. Since it has a simple structure, it can be accurately positioned and the biasing force of the spring can be set correctly.
Therefore, it is possible to surely perform the predetermined gap adjustment without causing an unbalanced load and a problem such as reverse rotation of the ratchet unlike the conventional case.

〔Example〕

Hereinafter, a wheel cylinder with an adjusting device according to an embodiment of the present invention will be described with reference to the drawings.

In the figure, the drum brake to which the wheel cylinder according to the present invention is applied is generally indicated by (1), and the wheel cylinder (2) is attached to the upper portion thereof. As is well known, a pair of arch-shaped brake shoes (3a) and (3b) are engaged with the both ends at their upper ends, and these are biased toward each other by a return spring (4). . Brake linings (5a) and (5b) are attached to the outer peripheral surfaces of the brake shoes (3a) and (3b), and a gap G adjusted according to this embodiment is provided between the brake linings (5a) and (5b). Has been formed.

As shown in FIG. 2, in the wheel cylinder (2), a cylinder hole (8) is formed in the cylinder body (7), and a first piston (10) having a cup seal (9) attached thereto is slidable. Is fitted to. In addition, facing this, the cup seal (1
The second piston (12) fitted with (1) is also slidably fitted. A hydraulic chamber ( 50 ) is defined between the first piston (10) and the second piston (12). It is connected via a pipe to a master cylinder which is connected to a brake pedal (not shown). Further, rubber dust covers (13) and (14) are worn between the outer peripheral surfaces of the first piston (10) and the second piston (12) and the cylinder body (7).

A hole (15) is formed in the second piston (12). Hole
A screw member (16) is concentrically fitted to (15),
(16) is slidable with respect to this hole (15), but is immovable in the axial direction. A screw is formed on the inner peripheral wall surface of the screw member (16), and the screw adjusting member (17) as the other screw member is screwed to the screw. This outer edge (17
An engaging part (20) is formed in a), and one end of the above-mentioned one brake shoe (3a) is engaged with this. Similarly the first
A groove (19) is also formed on the outer end of the piston (10), and this groove engages with the upper end of the other brake shoe (3b).

The outside of the cylinder body (7) is shown in Figs. 1 and 4 to 8
A cam plate (21) and an adjust lever (22), whose shapes are clearly shown in the figure, are vertically stacked and a spring (23) is stretched between them.

Next, the details of the cam plate (21) will be described. The shape is clearly shown in FIGS. 4 and 5, but it mainly consists of a flat portion (30), and in FIG. 4, a ring portion (31) is formed by bending at the right end portion. There is. This shape, which is clearly shown in FIG. 5, has a hole (31a) formed so as to fit the outer end portion of the screw member (16). Further, a projection (31b) is formed on this, and projection welding is performed on the outer end surface of the second piston (12). A first protrusion (32) and a second protrusion (33) are formed on the left end side so as to engage with the adjusting lever (22) and a part of the cylinder body (7) as described later. Is configured. Further, a small hole (34) is formed at the right end portion, and one end (23a) of the spring (23) is fixedly attached thereto.

Next, the details of the adjusting lever (22) will be described with reference to FIGS. 6, 7, and 8. This is the cylinder body
It is arranged outside the above-mentioned cam plate (21) on the outside of (7), and it is also mainly composed of a flat portion (41) and has a U-shape as a whole. Formed as 42). This has a shape as clearly shown in FIG. 8, and the tip portion thereof serves as a claw portion (43). Further, a round opening (44) is formed on the other end side so that the cam plate (21) and the pin (51) arranged below are connected with each other. The lower end of this other end in FIG. 6 is bent to the back side in the plane of FIG. 6 and further bent by about 90 ° as shown in FIG.
Is being formed. The shape is almost trapezoidal as shown in FIG. A gap S is formed between this and the flat portion (41). Further, a folded portion (46) is formed along the edge portion at the other end portion as shown in FIG. 6, and this end portion (46a) is formed on the other end portion (23b) of the spring (23) as shown in FIG. As shown in FIG.

The cam plate (21) and the adjusting lever (22) are configured as described above, and this combination will be described below. As shown in FIG. 1, these are arranged vertically, but the ring portion (31) of the cam plate (21) contacts the outer end surface of the second piston (12) and is projection welded. The outer end of the screw member (16) is located in this opening (31a), and the ratchet wheel (18) is fixed to this end face. The cam plate (21) extends above the cylinder body (7) as shown in FIG. 2, and the second protrusion (33) is arranged at a position where it abuts the pin (51). The first protrusion (32) is sandwiched in a gap S between the lateral protrusion (45) of the adjust lever (22) and the flat portion located on the upper surface.

The adjusting lever (22) is arranged above the cam plate (21), and the bent portion (42) has a shape as shown in FIGS. 8 and 3, but the claw portion (43) at the tip thereof. Engages the pawls (18a) of the ratchet wheel (18) as shown in FIG. An opening (44) is formed at the corner of the other end of the adjust lever (22), and a locking pin (51) is inserted through a clip (53), which is inserted into the opening (44). Cylinder body
It is fixed by being screwed into a screw hole formed as a flat portion on a part of the outer peripheral wall of (7). Therefore, as shown in FIG. 2, the adjusting lever (22) contacts the cam plate (21) and is stably arranged. In the combination structure as described above, the second protrusion (33) of the cam plate (21) is in contact with the pin (51),
Also, one end (23b) of the spring (23) is the end portion (46a) of the folded-back portion (46).
It is positioned and fixed as shown in FIG.
The coil portion (23c) as the main portion of the spring (23) extends along the edge portion (30a) of the flat portion (30) of the cam plate (21). Therefore, the spring (23) is positioned and positioned between the protrusion that fixes one end of the spring of the cam plate (21) and the first protrusion (32) of the cam plate. The compression restoring force of the spring (23) urges one end of the adjust lever (22) to the right in FIG. 1, and therefore the cam plate inserted in the space S above the lateral protrusion (45). The first protrusion of (3
2) is in pressure contact with the adjust lever (22) at the bent portion d (see FIG. 7).

Further, above the adjusting lever (22), a leaf spring (54) further has one end fixed to the pin (51) by a clip (53), and
The fastening portion (54a) formed at the other end is fastened to the hole (h) formed in the adjusting lever (22). By taking the shape shown in FIG. 2, the leaf spring (5
4) pushes the adjusting lever (22) downward. Therefore, the claw portion (43) formed at one end of the bent portion (42) of the adjust lever is reliably and elastically engaged with the tooth (18a) of the ratchet wheel (18). The embodiment of the present invention is constructed as described above. Next, this operation will be described.

When a brake pedal (not shown) is depressed, pressurized fluid is supplied to the fluid pressure chamber ( 50 ) of the wheel cylinder (2). As a result, the first piston (10) and the second piston (12) move in opposite directions, and the brake levers (3a) (3b) engaged with these outer ends.
The brake linings (5a) and (5b) attached to the outer peripheral portion of the brake drum (6).
Press against. Therefore, the wheels can be braked.

At this time, when the second piston (12) is moved to the right in FIG. 2, the screw member (16) fitted to the second piston (12) is also moved to the right. In FIG. 1, since the cam plate (21) is driven rightward, the spring (23) and the adjusting lever (2
The adjusting lever (22) is driven rightward together with the cam plate (21) through the bent portion (2). Therefore, the adjusting lever (22) is rotated counterclockwise around the stop pin (51). Therefore, the claw portion (43) formed at one end of the adjust lever is engaged with the claw (18a) of the ratchet wheel (18) and is driven to move the ratchet wheel (18) clockwise in FIG. Rotate. Then, when the brake is released, the hydraulic pressure in the hydraulic chamber ( 50 ) decreases, so that the first piston (10) and the second piston (12) move in the directions in which they approach each other. Therefore, the screw member (16) also moves to the left in FIG. 2, and at this time, the adjusting lever (22) rotates around the stop pin (51) in the clockwise direction in FIG.
If brake lining (5a) (5b) and brake drum (6)
If the gap G between and is larger than a predetermined value, that is, if the brake lining is worn out by a predetermined value or more, the rightward movement of the second piston (12) becomes large when the brake is applied. The amount of movement of the screw member (16) and the screw adjusting member (17) to the right also increases. Therefore, the screw member
In FIG. 1, the adjusting lever (22) rotatably supported by the pin (51) on the cam plate (21) by the movement to the right by a predetermined value or more in FIG. Then, the ratchet wheel (18) is rotated clockwise by that amount in FIG. Rotation of the ratchet wheel (18) causes the screw member (16) integral with the ratchet wheel (18) to rotate, whereby the screw adjusting member (17) moves to the right in FIG.

When the brake is released, the hydraulic fluid in the hydraulic chamber ( 50 ) is released,
The second piston (12) moves to the left, and the adjusting lever (2
2) is rotated clockwise in FIG. 1, and the claws (43) of the adjust lever (22) are fitted with teeth (18) of the ratchet wheel (18).
The ratchet wheel (18) is not swiveled over the a).

As a result, the brake is applied and the brake levers (3a) (3b)
The brake lining (5a) (5
The gap G between b) and the brake drum (6) is set to a predetermined value. Therefore, the adjusting action was performed.

The embodiment of the present invention has the above-mentioned configuration and operates, but has the following effects.

That is, the spring (23) is the cam plate (21) according to the present embodiment.
Is guided and positioned on one side by the flat part (30) of
Further, since one end (23b) of the cam plate (21) is positioned and guided by being fixed to the end (46a) of the folded back portion (46), the cam plate (21) moves without rattling, and The adjusting lever (22) can be surely rotated in a predetermined manner, and thus the above-mentioned gap adjusting operation can be surely performed.

Further, according to the present embodiment, the leaf spring (54) is provided, and the pawl portion (43) of the adjusting lever (22) is provided at one end of the leaf spring (54) with the ratchet wheel.
Since the teeth (18a) of (18) are elastically pressed, the gap adjustment function may not be able to be performed if the engagement has rattling in the past, but according to the present embodiment, there is some rattling. Even if there is, the ratchet wheel can be reliably rotated to perform a predetermined clearance action.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the leaf spring (54) may be omitted. Further, in the above embodiment, one spring (23) is used, but it may be provided in parallel in the lateral direction to provide two or more digits.

Although only a part of the drum brake is shown in the above embodiments, this embodiment is of course applicable to all types of drum brakes.

[Effect of device]

As described above, according to the wheel cylinder with the adjusting device of the present invention, the gap adjusting action can be surely performed.
In addition, since the first bent portion with which the hook portion of the spring of the adjusting lever engages has a shape that is substantially along the shape of the hook portion,
Positioning of the spring in the plate thickness direction can be performed.

[Brief description of drawings]

FIG. 1 is a partial plan view of a drum brake to which the wheel cylinder with an adjusting device of the present embodiment is applied, FIG. 2 is a longitudinal sectional view of the wheel cylinder of the same embodiment, FIG. 3 is a front view, and FIG.
FIG. 5 is a plan view of a cam plate in the same embodiment, FIG. 5 is a front view of the same, FIG. 6 is a plan view of an adjust lever in the same embodiment, FIG. 7 is a side view and FIG. 8 is a front view. In the figure, (21) …… Cam plate (22) …… Adjust lever (23) …… Spring (30) …… Flat part (46) …… Folded part

Claims (1)

[Scope of utility model registration request] 1. A cylinder main body having a cylinder hole, a piston slidably inserted into the cylinder hole to define a pressure chamber, and a piston arranged between the piston and a brake friction material to adjust the length. A pair of screw members that can be screwed together, a ratchet wheel formed on one of the screw members, a plate member that is movable along the cylinder body outside the cylinder body, and is interlocked with the piston, A plate-shaped adjustment lever having a claw portion that is rotatably supported outside the cylinder body and that can engage with the ratchet in one direction, and urges the adjustment lever and the plate member in a direction in which they abut each other. In a wheel cylinder with an adjusting device including a spring and a U-shaped hook portion formed on one end side of the spring and engaging with the adjusting lever, the hook portion of the adjusting lever engages. A first bent portion that substantially conforms to the shape of the hook portion is formed, and one side surface side of the spring is positioned by a flat portion formed on the plate member, and the other side surface side is the first bent portion. A wheel cylinder with an adjusting device which is positioned by bringing the side surface of the hook portion into contact with the end surface of the second bent portion extending from the wheel cylinder.