JPS5824625A - Drum brake - Google Patents

Abstract

PURPOSE:To provide a drum brake which can be reduced to compact size and light weight by disposing a wheel cylinder outside of the range partitioned by a drum of the drum brake and a backing plate so as to left a margin for space capacity in the drum. CONSTITUTION:In case of a duo-servo drum brake, a double-acting wheel cylinder 8 is secured to the outer surface of a backing plate 1 near an anchor pin 5 fitting position, and projections 10a, 11a of a pair of transmitting links 10, 11 are brought into contact with the ends of pistons 9, 9. Operating parts 10b, 11b are formed on the opposite side to the projections 10a, 11a of the transmitting links 10, 11 through sliding guide members 10c, 11c, and the operating parts 10b, 11b are engaged with outer edges of engaging holes 2a, 3a. Such construction of the drum brake can produce a margin in space capacity so as to reduce the drum brake to compact size and light weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compact drum brake that can exhibit the same performance with a smaller drum diameter.

In response to the energy crisis, there has been a demand for lighter cars to improve their fuel efficiency.

Furthermore, with the shift to FF (front engine, front drive), passenger cars are using disc brakes on the front wheels to shoulder the increasing load distribution on the front wheels, while lightweight and inexpensive drum brakes are being used on the rear wheels. There is a need to suppress the increase in weight due to noise regulations by reducing the weight of each component, including the brake. On the other hand, the load on brakes is increasing due to the construction of expressways.

In view of these circumstances, the present invention proposes a drum brake that uses a wheel cylinder as a brake input source, but since the conventional structure is such that the wheel cylinder is sandwiched between the ends of opposing brake shoes, Focusing on the fact that there are restrictions on the structure of By adopting a structure that transmits input to the brake shoes, it is easy to arrange parts inside the drum for drum brakes with a conventional drum diameter, and for drum brakes with the same brake function as conventional drums, The object of the present invention is to provide a drum brake that can meet the above-mentioned requirements by reducing the amount of power used.

Embodiments of the drum brake according to the present invention will be described below with reference to the drawings.

1 to 3 show a first embodiment in which the present invention is applied to a duo-servo type drum brake. Brake shoes 2 and 3 (hereinafter simply referred to as shoes) are arranged opposite to each other on the inner surface of the backing plate 1, and one end thereof is connected to an adjuster device 4.
The other end is engaged with the anchor pin 5 and supported. A return spring 6.7 is stretched between the shoes 2, 3 and the anchor pin 5, and returns the shoe 2.3 to its original position by its restoring elastic force.

The double-acting wheel cylinder 8 has a backing plate 1
The piston 9.9 is fixed to the outer surface near the attachment position of the anchor pin 5, and the protrusions 10a and 11a of a pair of transmission links 10.11 are abutted or fixed to the tip of the piston 9.9. The transmission link 10.11 is approximately door-shaped and has protrusions 10a, l.
The opposite end of 1 m forms actuating parts 1ob and xtb, and the lower surface of the connection between protrusions 10a and l1m and actuating parts 10b and llb forms a sliding guide part 10 cr 11 a. The actuating parts 10b and llb are the packing plates 1.
As shown in the figure, insert the long holes 1a and la in the left and right direction from the outside of the backing plate to the inside to insert the shoes 2,
It is always engaged with the outer edges of the retaining holes 2m and 3m provided in 3.

Also, the operating part 10b, 1lb (7) shoulder part 10b', 1
Cut and raise l b' of backing plate 1
b.

1b, the transmission link 10.11 is prevented from coming off naturally, and the sliding portions 10e and 11 are brought into contact with the outer surface of the backing plate 1.

In this embodiment, when pressure i is introduced into the wheel cylinder 8 and the piston 9.9 expands, the transmission link 10.11 moves the sliding guide portions 10e, l in accordance with the amount of movement of the pistons 9, 9.
Slide the outer surface of the backing plate 1 with the lever. Actuation part 10b.

Since the shoes 2, 3- that engage with the drum 11b are expanded, both the shoes 2, 3 come into sliding contact with the drum 12 and generate a braking force. When the pressure fluid is discharged from the wheel cylinder 8, the shoe 2.3 returns to its original position by the return spring 6.7. Note that if the transmission link 10.11 is fixed to the pistons 9, 9, the cut-and-raised pieces 1b, lb become unnecessary.

FIG. 4 shows a second embodiment of the present invention, in which the long arms 13m and 14m of a pair of double-shaped links 13 and 14 are inserted into the left and right elongated holes 1a and 1m from the inside of the backing plate 1 to the outside.
the inner surface of the tip of the piston 9.9.
It is in contact with. Further, the outer surfaces of the short arms 13b and 14b are supported by pins 15 set in the arms 5 so as to be swingable.

During braking, when pressure fluid is introduced into the wheel cylinder 8 and the piston 9.9 is expanded, the double-shaped link 13.14 is connected to the pin 1.
5, the shoes 2 and 3 are expanded by the increased pressing force and pressed against the drum 12 to generate braking force.

If the pressure fluid is discharged from the wheel cylinder 8, both shoes 2,
3 is returned to its original position by the action of return springs 6 and 7, and the double-shaped links 13 and 14 are also returned to their original positions.

FIG. 5 shows a third embodiment, in which a single-acting wheel cylinder 6 is fixed perpendicularly to the outer surface of the backing plate 1, and substantially parallel links 17. A connecting link 19 is pin-coupled to one end of III. A support link 21 is pin-coupled to the other end of 20.
The tip is engaged with piston #22. Link 17.
18 is swingably supported with its intermediate portion connected to a connecting link 23, 23 installed at a corresponding position on the outside of the single-acting wheel cylinder 6. Link 17,. 18
The other end is a long hole of 1 m in the left-right direction as seen in the figure, which is bored in the backing plate 1.

11 from the outside to the inside, and its outer surface is engaged with the outer edges of the retaining holes 2m and 3m of the shoes 2 and 3, respectively. A parking cable 24 is also connected to the support link 21.

Therefore, when the pressure fluid is introduced into the single-acting wheel cylinder 16ζ, the piston 22 moves in the longitudinal direction of the link 17.18, and the link 17 and IJI are swung through the support link 21 and the articulating link 19.20. Shoe retention hole 2
Since the distance between the other ends engaging with the shoes m and 3m is expanded, both the shoes 2 and 3 slide against the rotating drum 12 and generate a braking force. Once the pressure fluid has been discharged, the return springs 6, 7 return the shoe 2.3 with the link 17.18 to its original position. If the parking cable 24 is pulled in the direction of movement of the piston 22 of the wheel cylinder by operating a parking lever (not shown), a braking force is generated in the same way as when pressure fluid is introduced into the wheel cylinder 16, and the parking brake is activated. It can be operated as

FIG. 6 shows an implementation of the third embodiment shown in FIG. Link 17.18, connecting link 19°20, support link 2
1 is the same as in the third embodiment. Join link 2
3 is integrally fixed to the outer surface of the backing plate 1 with legs 231 in the center. Single acting wheel cylinder 16
is fixed to the axle pipe 25 which is a non-rotating part of the vehicle, and one end of the swing link 26 is swingably supported on the axle pipe 25, and the other end of the swing link 26 is connected to the middle of the parking cable 24, which is connected to the support link 21. The piston 22 of the cylinder abuts on a suitable intermediate portion of the swing link 26. Therefore, by introducing or discharging pressurized liquid into the foil cylinder 16, it operates in the same manner as the third embodiment.

7 to 9 show a fourth embodiment in which the present invention is applied to a leading trailing brake. The other end of the shoe 2 is brought into contact with the tip of the piston 22 of the single-acting wheel cylinder 16 whose base end is fixed to the outer surface of the backing plate 1, and is connected to the parking cable 24. The link constituted by the adjuster device 29 is supported and interposed between the central portion of the wedge-shaped link 28 and the externally applied shoe 3 by, for example, being coupled with a bottle.

By introducing pressure fluid into the single-acting wheel cylinder 16 or pulling the parking cable 24, both shoes 2,
3 expands and comes into sliding contact with the drum 12, producing a braking force. When the pressure fluid is discharged from the wheel cylinder 16 or the operation of the parking lever (not shown) is released, both shoes 2 and 3 return to their original positions by the action of the return spring 30. In this embodiment, both shoes 2 are adjusted by the operation of the adjuster device 29.
, 3 and the drum 12 can be maintained constant.

In the second to fourth embodiments, the pressing force of the shoes 2 and 3 is increased by selecting a large lever ratio -g+/13t of the components of the link device shown in each figure and the special number shown in the drawing. Can be communicated.

Although the present invention has been described above with respect to a brake having one wheel cylinder, it can be similarly applied to a drum brake using a plurality of wheel cylinders.

Since the drum brake according to the present invention is constructed as described above, it produces the effects described below.

(1) By installing the wheel cylinder in a non-rotating part of the vehicle outside the area defined by the drum and backing plate, an extra space is created within the drum.
We were able to reduce the weight of the drum brake shed.

(2) Except for the first embodiment, by appropriately selecting the link length of the link device that connects the piston and shoe of the wheel cylinder and changing the lever ratio, the same method can be used for the wheel cylinder of the shed than in the past. braking force can be obtained.

(3) [3. In the fourth embodiment, the parking brake can be easily installed.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the drum brake according to the present invention, FIG. 1 is a plan view excluding the drum, and FIG.
3 is a BB sectional view, FIG. 4 is an end view similar to FIG. 2 showing the second embodiment, and FIG. 5 is a second diagram showing the third embodiment. FIG. 6 shows an embodiment of the third embodiment, FIG. 6B) is a side view showing the installed state, FIG. The figure shows the fourth embodiment, FIG. 7 is a plan view excluding the drum, and FIG. 8 is a D
-D end view, and FIG. 9 is a sectional view taken along E-E. 1: Packing plate, 2 = Brake shoe, 3 Ni brake shoe, 8: Double acting wheel cylinder, 10: Transmission link, 11: Transmission link, 12 Ni drum, 13: z
Figure-shaped link, 14: 2-shaped link, 16: Single-acting wheel cylinder, 17: Parallel link, 18: Parallel link, 1
9: articulating link, 20: articulating link, 21: supporting link, 23: joining link, 2s: axle tube, 26: swinging link, 28: <shaped link.

Claims (1)

[Claims] In a drum brake that uses a wheel cylinder as a brake input source, the wheel cylinder is fixed to a non-rotating part of the vehicle outside the range defined by the drum and the backing plate, and is placed opposite the backing plate. A drum characterized in that a link device including a link through which a packing plate is inserted is provided between the brake shoe and the piston of the wheel cylinder, and the link device transmits the operating force of the piston of the wheel cylinder to the brake shoe. brake.