JPS58106231A - Drum brake device - Google Patents

Abstract

PURPOSE:To make proper the amount of adjusting by an adjuster, by restricting the movement of an anchor pin, at the time of gap adjustment, by means of the other brake shoe than that guiding the adjusting cable, making contact with the anchor pin. CONSTITUTION:At the time of service brake, a piston 6 pushes the top 4a of a rear located brake shoe 4 and the end part 4b pushes the end 3b of the front brake shoe 3 through an adjuster 17, so that two trailing is obtained. At the time of parking brake, brake shoes 3, 4 are moved clockwise by the friction force with the brake drum 1, and the top 4a of the rear brake shoe 4 makes contact with the anchor pin 15, and at the same time, the top 3a of the front brake shoe 3 separates from the anchor pin 15. When the distance between these two 15, 3a becomes large at this time, the adjuster 17 is stretched.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drum brake device which forms a double-circuit type during parking braking.

A conventional drum brake device of this type is shown in FIG. 1 (Japanese Patent Laid-Open No. 10834/1983). In other words, 1 is the brake drum, 2 is the knock plate,
3 is the front brake shoe.

4 is a rear brake shoe, a wheel cylinder 5 is fixed to the pack plate 2, one end 6a of the front brake shoe 6 is opposed to this wheel cylinder 5, and one end 4a of the rear brake shoe 4 is connected to the wheel cylinder. Opposite Piston B of 5.

The other end 5b of these front and rear brake shoes 6,4.

A connecting member 7 is inserted between 4b. Then, the free end 9b of the lever 9, whose base 9a is pivoted to one brake shoe 4 via the pin 8, is connected to the cable 10 of the chisel-king brake operating device, and the lever 9 and the other brake shoe 4 are connected to each other. A strut 11 is interposed between the brake shoe 6 and the brake shoe 6. 12.13
is Plenikish-6.

This is a return spring stretched between 4.

During service braking, when the hydraulic pressure generated in the master cylinder due to the force applied to the brake pedal acts on the wheel cylinder 5, the piston 6 moves to f 1ifll.
The upper end 4a of the brake shoe 4 is pressed against the brake drum 1 rotating in the direction of the arrow during forward movement, and the lower end 4b of the shoe 4 is connected via the connecting member 7 to the lower end 6b of the front brake shoe 6. Press. Since the upper end 6a of this shoe 6 faces the wheel cylinder 5 fixed to the knock plate 2, the lower end 6a
When b is pushed outward, the upper end 6a collides with the wheel cylinder 5, and using this collision point as a fulcrum, the front 1u11
The brake shoes 6 are also pressed against the inner peripheral surface of the brake drum 1. In this case, the rotational direction of the brake drum 1 (in the direction of the arrow) and the brake shoe 6 when the vehicle moves forward.
．． Since the direction of the force transmitted to 4 is opposite, there is two-trailing and the braking force during service braking is not very high.

In order to apply the parking brake, when the brake lever facing the driver's seat is operated, the brake lever 9 rotates clockwise in the figure using the pin 8 as a fulcrum via the cable 10. When Leno-9 rotates, Stra, T1
1, the upper part of the front brake shoe 6 is pushed outward, and as a reaction, the upper part of the rear brake shoe 4 is also pushed outward and brought into pressure contact with the inner peripheral surface of the brake drum 1. Therefore, the braking action in this case is
It becomes very large because it acts as a duosurge type.

However, in such a drum brake device, instead of the connecting member 7, an auto adjuster is inserted between the ends 3 b t J b of the brake shoes 3 and 4.
This adjuster's adjuster ζ-.

By connecting the wheel cylinder 5 or a pin fixed in the vicinity thereof with an adjustment cable, and pushing apart the end portions 3b and 4b of the brake shoes 3 and 4 using an auto adjuster when the nozzle king brake is activated,
If the brake shoe 6.4 is configured to adjust the distance between the inner peripheral surface of the brake drum 1, the following problems occur. Namely.

When the parking brake is applied, the brake shoes 6.4 are expanded and pressed against the inner shield surface of the brake drum 1, and when a rotational force is applied to the brake drum 1 in this state, the brake shoes 3
, 4, either of the end portions 3a, 4a of the wheel cylinder 5
Or, the piston 6 moves in the vertical direction in FIG.
move away from

In this way, when the ends 6a, 4a move in the vertical direction in the figure, the amount of tension on the adjustment cable is not determined only by the distance between the brake shoe 6.4 and the brake drum 1; The end portion in the vertical direction, lSa, 4
The amount of movement of a will also have an effect. From this,
When an auto adjuster is installed between the ends 3b and 4b of the brake shoes 3 and 4, the amount of adjustment obtained by this is also affected by the amount of movement of either of the ends 6a, 4a of the brake shoes 6.4 in the vertical direction in the figure. However, there is a problem that it is easy to be inaccurate.

The present invention has been made in view of these conventional problems, and includes an anchor pin fixed to a knock plate between one opposing end of the front brake shoe and the rear brake shoe. A lever interposed therebetween, with the piston of the wheel cylinder facing only the rear brake shoe on the anchor pin side, and pivotally connected to the anchor pin side of one brake shoe and interlocked with the parking brake lever;
A strut is hung between the other brake shoe on the anchor pin side, and an adjuster is hung between the opposite ends of both brake shoes, and a strut is placed between the adjustment levers of this adjuster and the anchor pin. It is an object of the present invention to solve the above-mentioned problem by letting the brake shoe guide the middle part and then wrapping the adjustment cable around it.

The present invention will be described below with reference to illustrated embodiments. Second
The figure shows an embodiment of the present invention.

First, to explain the structure, 1 is a brake drum that rotates in the direction of the arrow when the vehicle moves forward, 2 is a knock plate,
3 is a front brake shoe, and 4 is a rear brake shoe. An anchor pin 15 is fixed to the knock plate 2, and one end 3a, 4a of each brake shoe 3. .

Push the piston 6 of the single-open wheel cylinder 5 fixed to the knock plate 2 so as to face the anchor pin 15 so as to sandwich it therebetween, and near the anchor pin 15 side of the rear brake shoe 4. Further, an adjuster 17 is inserted between the other opposing ends 3b and 4b of the front and rear anti-brake shoes 6.4. The adjuster 17 is connected to the ends 6b + 4 of both brake shoes 3 and 4.
By adjusting the distance between the brake shoes 6 and
．． 4 and the inner circumferential surface of the brake drum 2, and a known one is used. Reference numeral 18 denotes an adjustment lever rotatably attached to the front brake shoe 6, and a pawl of this lever engages with a mold wheel 17a of the adjuster 17. Adjuster bolts-18 and anchor pins 15
An adjustment cable 19 is strung between the two and the middle part of the adjustment cable 19 is guided to a cable guide 3C formed on the front brake shoe 6. Reference numeral 19a is a fitting for attaching the end of the adjustment wire 19. Also, Adjust True No-18.

A return spring 16 is placed between the rear brake shoe 4 and the adjustment lever 18 in the counterclockwise direction in the figure.
b,, 4 energizes b in the direction of bringing them closer together.

In addition, the levers 9 are pivotally supported on the pin 8 attached near the anchor pin 15 of the front brake shoe 3.

The cable 1 of the parking brake device is connected to the free end 9b.
Connect 0. A strut 11 is installed between the lever 9 and the rear brake shoe 4 at a position on the anchor pin 15 side.
Interpose. 11a is a coil spring that elastically supports the strut 11 on the brake shoe 4. Reference numeral 20 denotes a hole formed in the pack plate 2 to communicate the inside and outside of the brake drum 1, and the cable 1o passes through the hole 20.

21 is a shoe hold down spring that floatingly supports the brake shoes 3 and 4 on the knock plate 2;
5, return springs I2a and 12b are installed respectively. A leaf spring 22 prevents the ends 3a, 4a of the brake shoes 3, 4 from being pulled out in the axial direction of the anchor pin 15.

Next, the effect will be explained.

During service braking, when the hydraulic pressure generated in the master cylinder due to the force applied to the brake pedal is transmitted to the wheel cylinder 5, the piston 6 pushes the upper end 4a of the rear brake shoe 4, and when moving forward, the piston 6 pushes the upper end 4a of the rear brake shoe 4. The brake shoe 4 is pressed against the rotating brake drum 1, and the lower end 4b of the brake shoe 4 in FIG. 1 pushes the end 6b of the front brake shoe 3 via the adjuster 17. The upper end 6a of this shoe 6 is fixed to the pack plate 2 and faces the t-anchor pin 15, so when the lower end 6b is pushed outward,
The upper end portion 6a abuts against the anchor bin 15, and the front brake shoe 6 is also pressed against the inner peripheral surface of the brake drum 1 using the anchor bin 15 as a fulcrum. Thus, in this case, when the vehicle moves forward, the direction of rotation of the brake drum 1 (in the direction of the arrow) and the direction of the force transmitted to the brake shoe 6.4 are opposite, resulting in trailing and no surge effect. Therefore, the braking force during service braking is not very high, as shown by the solid line in Fig. 3 (the broken line in the figure indicates the braking force of the leading-trailing type brake.

). Therefore, is it possible to install this drum brake on the front wheel?
If used on the rear wheels of a vehicle with ineffective disc brakes, the braking performance of the front wheels will match.
The stability of braking distribution can be maintained.

Furthermore, when the driver operates the brake levers facing the driver's seat in order to apply the parking brake, the brake levers 9 rotate clockwise about the pin 8 via the cable 10. When the Leno-9 rotates, the upper part of the rear brake shoe 4 is pushed outward via the strut 11°, and as a reaction, the front brake shoe 6 is pushed out via the pin 8 of the Leno-9. The upper portions of the brake drums are also pushed outward and are pressed against the inner peripheral surface of the brake drum 1, respectively. Then,
The braking action during no-king braking is very large because it works as a duo servo type, thus ensuring that the vehicle is maintained in a parked state.

By the way, when the brake drum 1 is rotating or about to rotate in the direction of the arrow (i.e., the forward direction of the vehicle) during chisel-king braking, the brake shoes 6.4 are rotated due to the frictional force with the brake drum 1.・、
In the figure, move clockwise to the rear brake shoe 4.
The upper end 4a collides with the anchor bin 15, while the upper end 6a of the front brake shoe 6 separates from the anchor bin 15.

At this time, the distance between the two 15.3a is the door rake shoe 6.
．． It increases in accordance with the wear amount of 4. When the amount of wear increases and the amount of movement of the brake shoe 6.4 becomes small, the cable guide 6C of the brake shoe 6
Pull out the adjustment cable 19 and adjust the cables...18.

It is rotated against the bias of the return spring 16. As a result, the claws of the adjuster levers 18 rotate the model wheel 17a of the adjuster 17, thereby extending the adjuster 17, thereby causing the end portions 6b of the playback needles 3, 4 to
4b are widened to maintain an appropriate distance between the brake shoes 3, 4 and the inner circumferential surface of the brake drum 1 when the brake is not in operation. The amount of extension of the adjuster 17 at this time is determined by the wear amount of the brake shoe 6 (, +4).

Since the distance between the anchor bin 15 and the end of the brake shoe 3 corresponds to the amount of tension of the adjustment cable 19 determined by this distance, an appropriate adjustment action can be obtained at all times.

As explained above, according to the present invention, an anchor pin fixed to the respective lock plates is interposed between one opposing end of the front brake shoe and the rear brake shoe, and the anchor pin side Only the rear brake shoe faces the piston of the wheel cylinder, and between the brake shoe that is pivoted to the anchor pin side of one brake shoe and interlocks with the parking brake brake shoe and the other brake shoe. The strut is hung on the anchor pin side, and the adjuster is hung between the opposite ends of both brake shoes. Because the adjustment cable is hung by letting the adjuster guide the middle part, when the adjuster adjusts the distance between the brake shoes and the brake drum, a brake shoe other than the one that guides the adjustment cable collides with the anchor bin, causing damage to the cable. Movement will be regulated. Therefore, the amount of movement of both brake shoes corresponds to the amount of wear of the brake shoes, so
The adjuster will expand by a size commensurate with the amount of wear. Therefore, according to the present invention, there is an effect that the amount of adjustment by the adjuster is optimized, and since this drum brake device does not have a surge effect during service braking, it is possible to use a disc brake that does not have a surge effect for the front wheel brake. If used on the rear wheels of a vehicle, the balance between the braking forces of the front and rear wheels will be improved and the braking performance will be stable.At the same time, when the parking brake is applied, since it acts as a duo-ser Z type, the 1x force effect will be greater and the braking performance will be improved. It also has an improving effect.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of a conventional example, Fig. 2 is a front sectional view showing an embodiment of the present invention, and Fig. 3 shows the relationship between the braking force during service braking and the coefficient of friction of the lining material. It is a graph. 1...brake drum, 2...notsuku plate,
3.4... Brake shoe +, 3as3tz4a, 4b
... End, 3c... Cable guide, 5... Wheel cylinder/, 6... Piston, 8... Bin, 9...
...Reno-110...Cable, 11...Strut, 15...Anchor bin, 17...Adjuster, 18...Adjust lever, 19...Adjustment cable Patent applicant Nissan Motor Co., Ltd. Company Agent Patent Attorney Tetsuya Mori
Yoshiaki Naito, Patent Attorney Tadashi Shimizu 3b 4b Figure 2 / U42in7”J'j^ノIken11 / To the neck

Claims (1)

[Claims] An anchor pin fixed to the pack plate is placed between one opposing end of the front brake shoe and the rear brake shoe, and the wheel cylinder is attached only to the rear brake shoe with one anchor pin. With the pistons facing each other, connect the struts on the anchor pin side to the parking brake levers, which are pivoted to the anchor pin side of one brake shoe and interlock with the parking brake levers, and the other brake shoe's LT4. Furthermore, an adjuster is hung between the other opposing ends of both brake shoes, and the middle part is guided by one of the brake shoes between the adjustment lever of this adjuster and the anchor pin to adjust the adjuster.
A drum brake device characterized by a $ cable wrapped around it.