JPH0638192Y2 - Drum brake - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a drum brake which is preferably used for applying a braking force to a vehicle, for example, and more particularly to a drum brake of a type in which a parking brake is integrally incorporated. Regarding

[Conventional technology]

The present applicant has proposed various drum brakes in JP-B-55-34344 and JP-B-57-12269.

Therefore, FIGS. 7 to 9 show a conventional drum brake of this type.

In the figure, reference numeral 1 denotes a back plate which is located on one axial side of a brake drum (not shown) that rotates integrally with a vehicle and wheels and is fixed to a non-rotating portion of the vehicle. It is formed by press-molding a disc-shaped metal plate or the like as shown in FIG. 8, and the back plate 1 is provided with a circular mounting hole 1A for mounting a stopper 12 described later. Also,
A wheel cylinder 2 and an anchor 3 are provided on the back plate 1 at positions diametrically opposed to each other. The wheel cylinder 2 is provided with a brake fluid pressure from a master cylinder (neither is shown) when the brake pedal is operated. Are being supplied. A pair of pistons (not shown) for pressing the brake shoes 4 described later against the brake drum are slidably fitted in the wheel cylinder 2.

Reference numerals 4 and 4 denote a pair of brake shoes that frictionally engage with the brake drum to provide a braking action. Each of the brake shoes 4 is formed in a crescent shape, and a lining 4A, 4 is provided on the outer peripheral side thereof.
A is attached to each. One end of each brake shoe 4 is attached to each piston of the wheel cylinder 2, and the other end is in contact with the anchor 3. Also,
Return springs 5 and 6 are stretched between the brake shoes 4, and the springs 5 and 6 constantly urge the brake shoes 4 to the non-braking side.

Reference numeral 7 denotes a strut suspended between each brake shoe 4, and one end side 7A and the other end side 7B of the strut 7 are engaged so as to abut against each brake shoe 4, and the axial middle portion thereof is An adjusting unit 8 is provided that adjusts the overall length of the strut 7 by appropriately changing it. That is, the strut 7 is formed so as to be expandable and contractable by a double cylinder pair or the like, and the adjusting portion 8 gradually extends the strut 7 according to the frictional condition of each lining 4A at the time of braking operation, and the lining 4A and the brake drum are The gap between them is adjusted.

9 cooperates with the strut 7 when operating the parking brake,
A hand brake lever for pressing each brake shoe 4 against the brake drum is shown. One end side of the hand brake lever 9 is attached to one brake shoe 4 via a pin 10, and the other end side is attached to a cable 11 as shown in FIG. They are connected as shown in FIG. The tip end side of the cable 11 is connected to a hand brake (not shown) as a parking brake operating means provided in a driver's seat of a vehicle, etc., and the hand brake lever 9 is operated in the direction of arrow B by the operation of the hand brake. It is designed to be rotated.

Here, when the hand brake lever 9 rotates in the direction of arrow B, the one brake shoe 4 is pressed toward the brake drum with the one end side 7A of the strut 7 as a fulcrum, and the one brake shoe 4 is braked. When you touch the drum,
This causes the strut 7 to move to the other brake shoe 4
And the other brake shoe 4 is also pressed to the brake drum.
Engage frictionally with the brake drum, for example as a parking brake. Further, an abutting portion 9A for the plug 13, which will be described later, is formed on the other end side of the hand brake lever 9, and the corresponding abutting portion 9A is formed.
By contacting the plug 13, the return position of the handbrake lever 9 is regulated.

Further, reference numeral 12 denotes a stopper that regulates the return position of the handbrake lever 9 when the parking brake operation is released, and the stopper 12 is a stopper portion 13A having a conical shape at the tip end side and a small diameter with the stopper portion 13A. A plug 13 made of a rigid material in which a locking step portion 13C having a diameter larger than that of the small diameter portion 13B is formed between the plug 13 and the back plate 1
It is fitted in the mounting hole 1A of the
A plurality of claw portions 14A to be locked to 13C is composed of a fixing member 14 made of an elastic material that is formed to be expandable and contractible, and the fixing member 14 inserts the plug 13 into the mounting hole 1A via each claw portion 14A. It is designed to be fixed in a state that it does not come off.

Here, the stopper 12 firstly includes the respective claw portions 14A of the fixing member 14.
While engaging the small diameter portion 14B of the plug 13, insert each claw portion 14A together with the stopper portion 13A of the plug 13 into the mounting hole 1A, and then pull out the plug 13 by pulling it out from the fixing member 14. , The claw portions 14A of the fixing member 14 to the locking step portion 1 of the plug 13
The plug 13 is locked to the mounting hole 1A by being locked to the 3C and forcibly expanding the diameter of each of the claw portions 14A. The stopper portion 13A of the plug 13 contacts the contact portion 9A of the handbrake lever 9 to regulate the return position of the handbrake lever 9.

The conventional drum brake has the above-described configuration. When the brake pedal is depressed while the vehicle is traveling, each piston in the wheel cylinder 2 slides due to the brake fluid pressure from the master cylinder. The brake shoe 4 is pressed against the brake drum and is used as a normal service brake.

On the other hand, when used as a parking brake, the hand brake lever 9 is rotated in the direction of arrow B via the cable 11 by pulling the hand brake, one brake shoe 4 is pressed against the brake drum, and the other hand. The brake shoes 4 are also pressed against the brake drums via the struts 7, and the brake shoes 4 are frictionally engaged with the brake drums. When the handbrake is returned to release the parking brake operation, the handbrake lever 9 rotates in the direction opposite to the arrow B direction and returns to the position shown in FIG. Contact part 9A
Comes into contact with the plug 13 of the stopper 12 to regulate the return position of the handbrake lever 9.

[Problems to be solved by the invention]

However, in the above-described conventional technique, when the stopper 12 is fixed to the circular mounting hole 1A formed in the back plate 1, each claw portion 14A of the fixing member 14 is forcibly elastically deformed by the plug 13 and each of the claw portions 14A is fixed. Since the diameter of the claw portion 14A is expanded and the plug 13 is prevented from coming off, unless the dimensional accuracy of the plug 13 or the fixing member 14 is strictly controlled, the deformation amount of each claw portion 14A exceeds the elastic limit, Each of the claw portions 14A may be damaged, and the reliability cannot be improved.

Further, the stopper 12 is not only difficult to improve the positional accuracy of the plug 13 when the plug 13 is fixed in the retaining state by the fixing member 14, but also pulls the plug 13 so as to be pulled out from the fixing member 14. Therefore, the work of fixing the plug 13 has to be performed, and at this time, it is necessary to pull it with a considerably strong force, which is a drawback that the workability is very poor.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. The present invention allows a stopper member for restricting the return position of the handbrake lever to be easily fixed to a stopper hole formed in the back plate, thereby improving reliability and reliability. Another object of the present invention is to provide a drum brake capable of improving not only position accuracy and the like, but also greatly improving workability when fixing a stopper member.

[Means for solving problems]

In order to solve the above-mentioned problems, the features of the configuration adopted by the present invention are: a stopper hole formed in the back plate, a stopper member attached to the stopper hole, and the stopper member positioned in the stopper hole. A fixing member, the stopper hole is formed from a wide insertion hole portion and an attachment hole portion that is continuous with the insertion hole portion and is narrower than the insertion hole portion; A stopper portion that regulates the return position of the handbrake lever, and when the stopper portion is inserted into the insertion hole portion of the stopper hole and is slid toward the mounting hole portion side, the stopper member is locked to the mounting hole portion. And a fixing member that fits into the insertion hole portion of the stopper hole via the stopper member,
The stopper member is fixed to the stopper hole of the back plate in a state where the stopper portion of the stopper member is locked to the mounting hole portion.

[Action]

With the above structure, when the stopper portion of the stopper member is inserted into the insertion hole portion of the stopper hole and then slid to the mounting hole portion side, the stopper retaining portion of the stopper member is kept in the retaining state around the mounting hole portion. Lock. Then, in this state, if the fixing member is fitted into the insertion hole portion of the stopper hole via the stopper member, the stopper member is positioned in the stopper hole by the fixing member, and the stopper portion of the stopper member holds the hand. The return position of the brake lever can be reliably regulated.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. Incidentally, in the embodiment, the above-mentioned FIGS.
The same components as those of the conventional technique shown in the figure are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 21 indicates a back plate fixed to a non-rotating portion of the vehicle,
Although the back plate 21 is formed in substantially the same manner as the back plate 1 described in the prior art, the back plate 21 faces the contact portion 9A of the hand brake lever 9 and the like, and a stopper hole 22 described later is formed. A flat portion whose portion is substantially parallel to the plate surface of the handbrake lever 9
It is 21A. Reference numeral 22 denotes a stopper hole formed in the flat portion 21A of the back plate 21 so as to face the contact portion 9A of the hand brake lever 9, and the stopper hole 22 is inserted through a stopper 23B of a stopper member 23 described later. The insertion hole 22A is formed in a wide rectangular shape, and the stopper 23B is formed in a narrow rectangular shape that is continuous with the insertion hole 22A and should regulate the return position of the handbrake lever 9. The mounting hole 22B is designed to have
It is formed in a letter shape.

23 is to regulate the return position of the handbrake lever 9,
A stopper member attached to the stopper hole 22 is shown. The stopper member 23 is formed of a resin material as shown in FIG. 5, and is formed in a rectangular shape wider than the stopper hole 22 and having a long length dimension. , A flange portion 23 which comes into contact with the upper surface of the flat portion 21A of the back plate 21 to cover the stopper hole 22
A, a stopper portion 23B projecting downward from a central portion of the lower surface of the flange portion 23A in a rectangular plate shape with a width dimension corresponding to the insertion hole portion 22A of the stopper hole 22, and the stopper portion 23B.
And a thick engaging portion 23C integrally formed on the lower surface side of the flange portion 23A with a shape corresponding to the mounting hole portion 22B of the stopper hole 22 on the upper side of the Part 23C
From the base end side and the tip end side of the back plate 21, the plate-like protrusions are provided in the left, right, and length directions of the back plate 21, respectively. The stopper portions 23D, 23D, 23E, the retaining portion 23E, the reinforcing portion 23F of a substantially right-angled triangle which is erected between the lower surface of the engaging portion 23C and the stopper portion 23B, and the reinforcing portion 23F and the like. Stopper on the opposite side
It is formed in the flange part 23A so as to contact with 23B, and the insertion hole part
The fitting hole 23G formed in a rectangular shape narrower than 22A and the upper surface of the flange portion 23A spaced apart in front of and behind the fitting hole 23G (left and right in FIGS. 1 and 3). And a pair of locking claw portions 23H, 23H projecting upward from.

Here, when the stopper member 23 is attached to the stopper hole 22, first, the stopper portion 23B is brought into contact with one side surface 22A ₁ (see FIG. 2) of the insertion hole portion 22A, and the stopper portion 23B and each retaining portion. Insert 23D, 23E, etc. into the stopper hole 22. Then, the flange portion 23A of the stopper member 23 is attached to the back plate 21.
The stopper member 2 is brought into contact with the upper surface of the flat portion 21A of the
3 is slid to the mounting hole 22B side along the flat portion 21A, the stopper 23B is brought into contact with the other side surface 22A ₂ of the insertion hole 22A, and the engaging portion 23C is fitted into the mounting hole 22B. To engage. As a result, each retaining portion 23D, 23E is first
As shown in FIGS. 4 and 5, the stopper member 23 is adapted to engage with the lower surface of the flat portion 21A of the back plate 21 around the mounting hole portion 22B.
Do not remove. Next, if the stopper member 23 is fixed as shown by a fixing member 24, which will be described later, the retaining portion 23D,
23E is fixed in a locked state, and the stopper portion 23B abuts on the abutting portion 9A of the hand brake lever 9 so that the torque lever 9
To regulate the position of.

Reference numeral 24 denotes a fixing member that positions the stopper member 23 in the stopper hole 22 of the back plate 21, and the fixing member 24 is formed of a resin material as shown in FIG. 6, and is substantially the same as the flange portion 23A of the stopper member 23. Flat plate portion 24A which is formed in a rectangular plate shape and is brought into contact with the upper surface of the flange portion 23A.
And a downwardly projecting shape having a shape corresponding to the fitting hole 23G of the stopper member 23 from the center of the lower surface of the flat surface portion 24A, and fitted into the insertion hole portion 22A of the stopper hole 22 via the stopper portion 23B of the stopper member 23. The projecting portion 24B to be fitted, and the projecting portion 24B is first
A pair of locking holes 24C, 24C, which are respectively formed in the flat plate portion 24A at positions separated left and right in the drawing, and through which the respective locking claw portions 23H of the stopper member 23 are inserted, and the respective locking holes 24C. The locking portions 24D, 2 which are formed around the periphery of the flat plate portion 24A so that the upper surface of the flat plate portion 24A is padded, and each locking claw portion 23H locks in a retaining state.
It is composed of 4D and.

The fixing member 24 is a stopper portion of the stopper member 23.
23B is inserted into the stopper hole 22 and slid, and the retaining portions 23D and 23E are locked around the mounting hole portion 22B as shown in FIG. Through hole
By fitting into 22A, each locking claw portion 23H is inserted into each locking hole 24C to lock each locking claw portion 23H to each locking portion 24D on the upper surface of the flat plate portion 24A, Stopper member 23
Is fixed to the stopper hole 22. Further, the fixing member 24 is provided with each locking claw portion 2 locked to each locking portion 24D.
The stopper member 23 is prevented from coming off by 3H.

The drum brake according to the present embodiment has the above-mentioned structure, and its basic operation is not different from that of the prior art.

However, in this embodiment, the contact portion of the hand brake lever 9 is
A substantially T-shaped stopper hole 22 including an insertion hole portion 22A and a mounting hole portion 2B is formed in a flat portion 21A of the back plate 21 facing 9A.
By inserting the stopper portion 23B of the stopper member 23 into the stopper hole 22 and sliding the stopper portion 23B toward the mounting hole portion 22B, the stopper portions 23D and 23E of the stopper member 23 are provided around the mounting hole portion 22B. It is designed to be locked in a state where it cannot be pulled out.

Then, in this state, the protruding portion 24B of the fixing member 24 is fitted into the insertion hole portion 22A via the fitting hole 23G of the stopper member 23, and each locking claw portion 23H of the stopper member 23 is locked into each locking hole 24C. Since the stopper member 23 is positioned and fixed in the stopper hole 22 by being locked to each locking portion 24D via the stopper member 23, the stopper member 23 can be reliably fixed in the stopper hole 22 and reliability can be improved. Further, the positional accuracy of the stopper portion 23B can be improved, and the return position of the hand brake lever 9 can be regulated at an accurate position.

That is, when the stopper member 23 is fixed by the fixing member 24, the stopper portion 23B of the stopper member 23 comes into contact with the other side surface 22A ₂ of the insertion hole portion 22A shown in FIG. ₂ , and the engaging portion 23C also has the attachment hole portion. 22B is engaged in the fitted state in 22B, and the mounting hole 2
The flat portion 21A of the back plate 21 located around 2B is the stopper member 2
Since it comes to be sandwiched between the flange portion 23A of 3 and the respective retaining portions 23D and 23E, the stopper portion 23B of the stopper member 23
Can be accurately positioned at a predetermined position.

Further, the stopper member 23 is fixed by inserting the stopper portion 23B and the like into the stopper hole 22 and sliding the stopper member 23B,
By simply pushing the fixing member 24 into the fitting hole 23G from above 23, the projection 24B of the fixing member 24 is fitted into the insertion hole 22A through the fitting hole 23G, and each locking claw portion Since 23H comes to be locked to each locking portion 24D through each locking hole 24C in a retaining state,
All the fixing work of the stopper member 23 can be easily performed only by linear movement, and the workability can be greatly improved.

Further, since the load at the time of returning the handbrake lever 9 is received by the stopper member 23, the load is not substantially applied to the fixing member 24, and the locking with each locking claw portion 23H is in the disengaged state. It is sufficient to hold the fixing member 24 and the stopper member 23, and the workability of attaching / detaching the fixing member 24 and the stopper member 23 can be greatly improved, and various effects can be obtained.

[Effect of device]

As described above in detail, according to the present invention, the back plate is provided with the stopper hole including the wide insertion hole portion and the narrow mounting hole portion,
Insert the stopper part of the stopper member into the stopper hole,
The stopper member is retained by the retaining portion by sliding it to the mounting hole side, and while keeping this retaining state,
Since the fixing member is fitted into the insertion hole portion of the stopper hole via the stopper member and the stopper member is fixed to the stopper hole of the back plate, not only can the fixing work of the stopper member be greatly simplified, The stopper member can be securely retained in the stopper hole of the back plate, and reliability can be improved. In addition, the return position of the handbrake lever can be accurately regulated by the stopper portion of the stopper member, and the positional accuracy can be improved, and other various effects are achieved.

[Brief description of drawings]

1 to 6 show an embodiment of the present invention, FIG. 1 is a longitudinal sectional view of an essential part of a drum brake, FIG. 2 is a plan view of an essential part of a back plate showing stopper holes, and FIG. 1 is a plan view of essential parts showing a back plate, a stopper member, a fixing member, etc. in FIG. 1, FIG. 4 is a rear view of FIG. 3, a back view, FIG. 5 showing the back plate, the stopper member, a fixing member, etc. in FIG. Is a perspective view showing a stopper member,
FIG. 6 is a perspective view showing a fixing member, FIGS. 7 to 9 show a conventional technique, FIG. 7 is a front view of a drum brake, and FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. FIG. 9 and FIG. 9 are enlarged views of the main parts in FIG. 4 ... Brake shoe, 9 ... Hand brake lever,
9A …… Abutting part, 11 …… Cable, 21 …… Back plate, 22 …… Stopper hole, 22A …… Insertion hole part, 22B …… Mounting hole part, 23 ……
Stopper member, 23A ... Flange part, 23B ... Stopper part, 23D, 23E ... Detachment prevention part, 23G ... Mating hole, 23H ... Locking claw part, 24 ... Fixing member, 24A ... Plate part , 24B ... Projection, 24C ... Locking hole, 24D ... Locking part.

Claims (1)

[Scope of utility model registration request] 1. A back plate, a pair of brake shoes mounted on the back plate and frictionally engaged with the brake drum to provide a braking action, and each brake shoe is pressed against the brake drum during operation of a parking brake. Accordingly, in a drum brake including a hand brake lever connected to a parking brake operating means via a cable, a stopper hole formed in the back plate, a stopper member attached to the stopper hole, and the stopper member. And a fixing member for positioning the stopper hole in the stopper hole, wherein the stopper hole has a wide insertion hole portion,
The stopper member is formed of an attachment hole portion that is continuous with the insertion hole portion and has a width narrower than the insertion hole portion. The stopper member controls the return position of the handbrake lever, and the stopper portion is the stopper portion. The fixing member is configured to include a retaining portion that engages with the attachment hole portion to prevent the stopper member from retaining when the insertion member is inserted into the insertion hole portion of the hole and slid to the attachment hole portion side, and the fixing member includes: A configuration in which the stopper member is fitted into the insertion hole portion of the stopper hole through the stopper member, and the stopper member is fixed to the stopper hole of the back plate in a state where the stopper portion of the stopper member is locked to the mounting hole portion. The drum brake characterized by