KR100349533B1 - Adjusting device of drum brake - Google Patents

Abstract

The present invention relates to an apparatus for adjusting a brake of a drum brake, and an object thereof is to improve an apparatus for compensating a gap between a drum due to wear of a lining and to reduce manufacturing costs, and to prevent unnecessary frictional damage of the lining and to provide a braking response. It is to improve sex.

In the drum brake adjuster 60 according to the present invention, a nut 66 is connected to an outer circumferential surface of the drum brake rod 63 to maintain a distance between the leading shoe 30 and the trailing shoe 40. The female push rod 61 and the second female push rod 62 are connected. When the linings 31 and 41 are worn, the nut is connected to the nut by a spiral spring 65 provided at the center of the female push rod 63. As the 66 is rotated immediately, the overall length of the adjuster 60 is extended.

Therefore, as soon as the lining 31 and 41 wear occurs, the overall length of the adjuster 60 is linearly expanded, so that the required amount of the wheel cylinder 50 is constant and the braking response of the drum brake is improved. In addition, since the components of the adjusting device 60 are simple, manufacturing cost is reduced, and the guide tube 67 for transmitting the elastic force of the spiral spring 65 to the nut 66 is an outer portion of the spiral spring 65. By being made in a cylindrical shape to surround the there is an advantage that the foreign material inflow is prevented.

Description

Adjusting device of drum brake

The present invention relates to a drum brake, and more particularly, to an apparatus for adjusting a brake of a drum brake, which compensates a gap between a lining and a drum when lining wear occurs due to repeated braking action.

In general, a brake mounted on a vehicle is a device for decelerating or stopping or maintaining a stopped vehicle. A brake that performs this function is a method of converting the kinetic energy during driving into thermal energy by a mechanical friction device to release its frictional heat into the air and braking, such as a drum hydraulic brake and a disk hydraulic brake.

Drum-type hydraulic brakes obtain a braking force by rubbing a cylindrical drum, which rotates with a wheel instead of a disk, with a lining therein. 1 is a front view showing a general structure of such a conventional drum brake.

As shown in the related art, conventional drum brakes have one end contacted and supported outwardly by a drum (1) rotating together with a wheel (not shown) and an anchor block (2a) fixed to the back plate (2). It consists of a pair of semi-circular brake shoes (3,4), a wheel cylinder (5) for operating the brake shoes (3,4) to receive the braking hydraulic pressure.

The brake shoes 3 and 4 are provided with linings 3a and 4a on the outer circumferential surface to exert friction braking force with the inner circumferential surface of the drum 1, which is the rotational direction of the drum 1 forward with respect to the wheel cylinder 5. It is distinguished as the trailing shoe 4 provided by the leading shoe 3 and the opposite side. The leading shoe 3 and the trailing shoe 4 are coupled to the semicircular rims 3b and 4b to which the linings 3a and 4a are attached and the inner circumferential surface thereof, and one end thereof is supported by the wheel cylinder 5 and the other end thereof. It consists of webs 3c and 4c in contact with the anchor block 2a, so that when braking the linings 3a and 4a operate outwardly so as to rub against the inner circumferential surface of the drum 1.

Restoring springs 8 are formed at both ends of the leading shoe 3 and the trailing shoe 4, so that when the braking action is released, the leading shoe 3 and the trailing shoe 4 are originally separated by the elastic restoring force. Return to the position of.

The wheel cylinder 5 is interposed between the leading shoe 3 and one end of the trailing shoe 4 webs 3c and 4c, and has a pair of pistons (not shown) which are advanced by braking hydraulic pressure. . And between the leading shoe (3) and trailing shoe (4) web (3c, 4c) male push rod (6a), female push rod (6b) and lever pwal (6c) There is an adjuster (6) made of a) or the like, which is extended when the nut 6f, which is engaged with the outer peripheral surface of the mail push rod 6a, is rotated.

Accordingly, when the linings 3a and 4a are over-weared by repetitive braking, the distance from the inner circumferential surface of the drum 1 is compensated by the adjuster 6, which will be described in more detail as follows.

First, the female push rod 6b is coupled to one end of the web 3c of the leading shoe 3, and the other end thereof is composed of a hollow portion. The male push rod 6a is composed of a spiral shaft (not shown) having a male thread formed on the outer circumferential surface of one end thereof so as to be freely fitted to the hollow portion of the female push rod 6b, and the other end thereof includes the trailing shoe 4. It is coupled with the parking brake actuating lever 7 provided on the web 4c. The parking brake actuating lever 7 has one end coupled with the trailing shoe 4 and the shaft 7a, and the other end is connected with a parking brake lever (not shown) provided next to the driver's seat through a cable (not shown). Braking is mechanically performed.

A nut 6f is screwed into the spiral shaft (not shown) of the male push rod 6a, so that the spiral shaft (not shown) of the male push rod 6a is further extended to the hollow side of the female push rod 6b. To prevent abnormal entry, gear teeth are formed at regular intervals on the outer circumferential surface thereof.

Then, the lever poles 6c (Lever Pawl) for rotating the nut 6f by using the elastic restoring force of the tension spring 6e when the linings 3a and 4a are over worn are installed. It is configured so that one end is coupled to the leading shoe 3 web 3c below the female push rod 6b using a roll pin 6d, and the other end is engaged with the gear teeth of the nut 6f. . Therefore, the lever pole 6c is rotated downward with respect to the roll pin 6d by the force which the tension spring 6e pulls downward.

That is, one end of the tension spring (6e) is fixed to the lever pole (6c) and the other end is fixed to the lower end of the leading shoe (3), when the lining (3a, 4a) when the braking action in a state of excessive wear The lever pole 6c is pulled downward so that the end portion rotates a predetermined angle in the direction of arrow A about the roll pin 6d.

As a result, the end of the lever pole 6c rotates the nut 6f so that the spiral shaft (not shown) of the male push rod 6a slightly comes out of the hollow portion, and the overall length of the adjuster 6 is extended. Even if the linings 3a and 4a are worn, the spacing from the inner peripheral surface of the drum 1 is kept constant.

However, such a conventional drum brake's adjuster 6 extends the overall length by using a gear gear formed on the outer circumferential surface of the nut 6f, thereby extending the length of the gear 6 with a gear gear, that is, about 2-3 mm of rotation. As a result, the linings 3a and 4a do not react immediately.

That is, it extends with the width | variety of one pitch of the gear tooth engaged with the edge part of the lever pole 6c. As a result, there is a gap change between the linings 3a and 4a corresponding to one pitch (2-3 mm) of the gear gear and the drum 1, and therefore, the required amount of the wheel cylinder 5 corresponding to the gap change amount. Change is needed. This acts as an inconsistent factor in brake responsiveness, reducing the reliability of the overall braking system.

The present invention is to solve this problem, the main object of the present invention is to install the nut that rotates so that the overall length of the adjuster to respond immediately when the wear of the lining using the spiral spring, the wheel cylinder required It is to provide a drum brake adjuster that maintains a constant amount of liquid to improve braking response and to simplify the overall component, thereby reducing manufacturing cost and making it compact.

It is a second object of the present invention to provide a drum brake adjusting device configured to have a guide tube for transferring the loosening force of a spiral spring to a nut to form a cylindrical shape to surround an outer portion of the spiral spring.

1 is a front view showing the overall structure of a conventional drum brake.

2 is a front view showing the overall structure of the drum brake according to the present invention.

3 is an exploded perspective view schematically showing the adjuster according to the present invention.

Figure 4 is a schematic view showing an internal structure and the coupling state of the adjuster device according to the present invention.

5 is a schematic view showing an operating state of the adjuster device according to the present invention during the braking action.

Figure 6 is a schematic diagram showing the operating state of the adjuster device according to the present invention during the braking action in the worn state of the lining.

7 is a schematic view showing a restored state of the adjuster device according to the present invention when the braking action is released.

* Description of the symbols for the main parts of the drawings *

60 .. Just device 61. First email push rod 62. Second email push rod

63..Mail Push Load 64..Disc Spring 65..Spiral Spring

66. Nut 67. Guide tube 69. Spacing spring

In order to achieve the above object, the present invention includes a drum that rotates with a wheel, a lining is attached to maintain a constant distance from the drum inner circumferential surface, and a leading shoe and trail that outwardly acts to exert a braking force by rubbing the inner circumferential surface of the drum during braking operation. When one end is coupled to the ring shoe and the leading shoe and the other end is coupled to the trailing shoe and the braking action is released, both ends between the restoring spring, the leading shoe and the trailing shoe to restore the leading shoe and the trailing shoe so that the lining maintains a constant distance from the drum. In the drum brake with the adjuster which is coupled to compensate the separation gap between the drum and the lining when the wear of the lining occurs,

The adjuster,

One end coupled to the leading shoe and the other end of the first female push rod formed in the insertion hole to a predetermined depth, the other end of the first female push rod axially spaced apart at a predetermined interval and the end is coupled to the trailing shoe One end portion is axially spaced to the insertion hole of the first female push rod to connect the second female push rod, the second female push rod and the first female push rod, and the other end has a spiral shaft. A spiral shaft of the mail push rod and the mail push rod that is inserted into and coupled to one end of the second female push rod gradually escapes from one end of the second female push rod, and is separated from the drum according to the wear of the lining. To compensate for this, one end is fixed on the center of the mail push rod to rotate the nut and the nut is rotated by being screwed to the spiral shaft, and the other end is wound to surround it. Spiral spring weaker than the elastic force of the ring, when the spiral spring loosening action, one end is fixed to the outer periphery of the nut so that the nut is rotated at the other end, the other end is wrapped around the outer space of the spiral spring, the other end of the spiral spring can be axially spaced When the spiral spring is loosened, the tube-shaped guide tube that rotates integrally to rotate the nut and the nut that receives the rotational force through the guide tube closely adhere to one end of the second female push rod when the lining wear does not occur. It is installed on the outer periphery of the mail push rod between the other end of the first push rod rod and the spiral spring side end to prevent the loosening action of the spiral spring so as to maintain the closed state, and they are elastically biased in the opposite direction, and its elastic force is weaker than the restoring spring. Stronger Disc than Spiral Spring It is characterized by including a spring.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. Figure 2 is a front view showing the overall structure of the drum brake according to the present invention, Figures 3 and 4 are combined cross-sectional view showing an exploded perspective view and the internal structure of the adjuster according to the present invention.

The drum brake according to the present invention is configured such that the cylindrical drum 10 rotates together with a wheel (not shown) as shown in the drawing, and outwardly acts on the edge of the back plate 20 to allow the drum 10 to rotate. A pair of brake shoes 30 and 40 with linings 31 and 41 attached to friction with the inner circumferential surface of the wheel, and a pair of pistons (not shown) to operate the brake shoes 30 and 40 under braking hydraulic pressure. Cylinder 50 or the like.

The brake shoes 30 and 40 are configured such that one end thereof is supported by the anchor block 21 and the other end thereof is in contact with the wheel cylinder 50, and that of the drum 10 in the forward rotation direction is the leading shoe 30, and vice versa. The one on the directional side is referred to as the trailing shoe 40. The leading shoe 30 and the trailing shoe 40 have a “T” shape in cross section. The welding means is applied to the inner circumferential surface of the semi-circular rim 32 and the rim 32 to which linings 31 and 41 are attached to the outer circumferential surface thereof. It is coupled through one end is supported by the anchor block 21 and the other end is made of a plate-shaped web (33, 43) in contact with the front end of the piston (not shown) built in the wheel cylinder (50).

On the other hand, when the lining (31, 41) is worn in accordance with the continuous braking action, the separation interval with the inner peripheral surface of the drum 10 increases, the compensation device 60 to compensate for such a constant always maintains the leading interval (Reading shoe ( 30) and the trailing shoe 40 is interposed. The adjuster 60 has a function of compensating the gap between the linings 31 and 41 and the drum 10, and the leading shoe 30 and the trailing shoe 40 are operated outwards, thereby making the parking brake work. Its detailed structure is as follows.

As shown in FIGS. 3 and 4, the adjuster 60 according to the present invention includes a first female push rod 61 having each end contacted with the leading shoe 30 and the trailing shoe 40. The second push rod rod 62 and the screw rod 632 is formed at the end thereof so that the nut 66 is rotatably coupled to the outer circumferential surface thereof. By rotating the nut 66 in one direction is made of a spiral spring 65 and the like to extend the overall length.

The first female push rod 61 has one end 611 in contact with the web 33 of the leading shoe 30, and an insertion hole 613 is formed to have a predetermined depth inside the other end 612. do. One end 631 of the male push rod 63 made of a rod is inserted into the insertion hole 613 to be coupled to the left and the right sliding, the other end 632 of the outer peripheral surface so that the nut 66 is engaged It consists of a spiral shaft machined with male threads.

Then, the second female push rod 62 is coupled to the one end portion 621 so that the mail push rod 63, the spiral shaft 632 portion is freely fitted, the other end 622 is connected to the trailing shoe 40. Shaft 71 is coupled to the parking brake operating lever 70 is coupled.

On the other hand, since the side surface portion of the nut 66 screwed to the outer circumferential surface of the spiral shaft 632 is in close contact with one end portion 621 of the second female push rod 62, this causes the nut 66 to rotate in the direction of arrow A. As a result, the spiral shaft 632 gradually exits the one end portion 621 of the second female push rod 62 so that the overall length of the adjuster device 60 is linearly elongated. same.

First, in order to rotate the nut 66 in the direction of arrow A, a spiral spring 65 is mounted at the center of the male push rod 63. The spiral spring 65 made of a plate has an inner end 651 firmly fixed to the outer circumferential surface of the mail push rod 63 using the fixing rod 633 and wound around the outer circumferential part thereof, so that it is a mail push rod 63. ), The unwinding force acts in the circumferential direction. Fixing rod 633 is fixed to the support portion 634 to be described later to extend in the axial direction on the outer circumferential surface of the mail push rod 63, the inner end 651 of the spiral spring 65 is fitted and coupled firmly installed do. The other end of the spiral spring 65 is connected to the outer circumferential surface of the nut 66 by using a cylindrical guide tube 67.

The cylindrical guide tube 67 of which both ends are hollow is configured so that the inner diameter is the same as the outer diameter of the nut 66, and one end 671 thereof is press-fitted to the outer circumference of the nut 66 to be firmly fixed. And the other end 672 of the guide tube 67 is wrapped around the outside of the spiral spring (65) spaced apart by a predetermined distance and the end thereof is coupled to the play. To this end, the other end of the guide tube (67) is formed with a guide groove (673) extending in a predetermined length in the axial direction, the other end of the spiral spring (65) is bent in the shape of the letter "B" to the coupling space 653 therein Coupling portion 652 is formed is formed.

Accordingly, when the coupling part 652 is inserted into the guide groove 673 through the coupling space 653, the other end 672 of the guide tube 67 may be free from the coupling part 652 of the spiral spring 65. By being coupled and slidable, the nut 66, which is connected through the guide tube 67, also rotates in the direction of arrow A when the spiral spring 65 is released in the direction of arrow A by the elastic force. At this time, since the guide tube 67 is configured to surround the outer circumferential portion of the spiral spring 65, the lining dust generated during the braking action is introduced into the spiral spring 65 and the disc spring 64 to be described later. Suppressed.

And between the other end 612 and the spiral spring 65 of the first female push rod 61 in order to prevent the loosening action of the spiral spring 65, except when the lining (31, 41) is worn On the outer circumferential surface of the male push rod 63, a pair of disk springs 64 which bias them in opposite directions are interposed. In order to install the disk spring 64, a support part 634 protruding in the circumferential direction is formed on the outer circumferential surface of the male push rod 63.

The pair of disk springs 64 formed to have a predetermined elastic force is formed through the central portion and the through hole 641 is fitted through the one end portion 631 of the mail push rod 63 is coupled to the support portion 634, Usually interposed in the compressed state between the other end 612 and the support 634 of the first female push rod (61).

The elastic region of the disk spring 64, that is, the width during the expansion is kept constant so that the gap G between the bottom of the insertion hole 613 and one end 631 of the male push rod 63 is constant. 5, G, which is the difference between the width in the compressed state where the load is applied to both ends of the disk spring 64 and the width in the removed state of the disc spring 64, is a predetermined width (an embodiment of the present invention). Is about 3 mm). As a result, the width in the compressed state is designed to be reduced by about 3 mm than the width without the external force applied to the disk spring 64. The gap of 3 mm is the maximum value at which the leading shoe 30 and the trailing shoe 40 are outwardly operated under normal braking action so that the overall length of the adjusting device 60 can be freely changed.

In addition, among these disk springs 64, spiral springs 65, and restoring springs 80 for restoring the leading shoes 30 and trailing shoes 40, the elastic force of the rest springs 80 is the strongest and then the disks. The spring 64 and the spiral spring 65 are comprised in this order. Therefore, when the braking action is released, since the leading shoe 30 and the trailing shoe 40 are restored by the elastic restoring force of the restoring spring 80, the disk spring 64 is squeezed and the nut by the elastic force of the disk spring 64. (66) The side end portion comes into close contact with one end portion 621 of the second female push rod 62 to prevent loosening of the spiral spring 65.

Next, the braking action of the drum brake according to the present invention configured as described above will be described.

First, before the driver presses the brake pedal (not shown), the disk spring 64 is maintained at the maximum compression state by the elastic force of the restoring spring 80. When the driver presses the brake pedal (not shown) in this state, The braking hydraulic pressure generated in the master cylinder (not shown) is transmitted to the wheel cylinder 50 so that the piston (not shown) is advanced. Therefore, the leading shoe 30 and the trailing shoe 40 are operated outwardly about the anchor block 21, so that the braking force is generated by friction with the inner circumferential surface of the drum 10 on which the linings 31 and 41 rotate.

In addition, when the leading shoe 30 and the trailing shoe 40 are pushed out due to the braking action, one end 611 of the first female push rod 61 and the other end of the second female push rod 62. External force applied to 622 is removed. Accordingly, as shown in FIG. 5, one end 631 of the male push rod 63 is pulled out of the insertion hole 613 of the first female push rod 61 by the expansion force of the disk spring 64. The overall length D2 of the adjuster 60 is extended. At this time, the length D2 of the adjuster device during the braking action is extended than the length D1 of the initial state, and its extension length is 3 mm or less.

Therefore, the expansion of the adjuster 60 is stopped before the pair of disk springs 64 are fully inflated, and the nut 66 side end and the one end 621 of the second female push rod 62 are in close contact with each other. By maintaining the state, the loosening action of the spiral spring 65 does not occur, so that the nut 66 is also not rotated.

That is, the overall length D2 of the adjusting device 60 is slightly extended during the braking operation in which the linings 31 and 41 are not worn, but the rotation of the nut 66 occurs because this occurs within the range of 3 mm. It doesn't work. This action is because the force in the axial direction due to the unwinding force of the spiral spring 65 is smaller than the expansion force of the disk spring 64.

When the braking action is released, the leading shoe 30 and the trailing shoe 40 are restored to their original positions by the elastic force of the restoring spring 80. At the same time, the disk spring 64 is compressed and the end of the mail push rod 63 is closed. The part 631 is inserted into the insertion hole 613 again, and the adjuster 60 also returns to its initial state.

On the other hand, when the linings 31 and 41 gradually wear out due to the repeated braking action, the outward working width of the leading shoe 30 and the trailing shoe 40 increases, in which case the nut 66 moves in the direction of arrow A. As the entire length of the adjuster 60 is extended immediately, the gap between the linings 31 and 41 and the inner peripheral surface of the drum 10 is always kept constant.

That is, when the wear of the linings 31 and 41 occurs, the operating width of the leading shoe 30 and the trailing shoe 40 increases, and the mail pusher is inserted from the insertion hole 613 of the first female push rod 61. By slightly exiting one end 631 of the rod 63, the disk spring 64 is inflated by a sufficiently free distance, the elastic force is no longer reached. In this case, the spiral spring 65 is immediately released by the elastic force to rotate the guide tube 67 and the nut 66 in the direction of arrow A.

Therefore, as shown in FIG. 6, the spiral shaft 632 of the male push rod 63 is pulled out of one end 621 of the second female push rod 62 so that the overall length of the adjuster 60 is reduced. It is slightly expanded, and the expansion force of the disk spring 64 again affects between the other end 612 and the support 634 of the first female push rod 61. At the same time, since the elastic force of the spiral spring 65 is smaller than the expansion force of the disk spring 64, the distance between the bottom of the insertion hole 613 and the one end portion 631 of the male push rod 63 is again maintained at the predetermined width G. No further rotation of the nut 66 occurs.

At this time, since the other end portion 672 of the guide tube 67 is slidably coupled in the axial direction through the coupling portion 652 provided at the end of the spiral spring 65, according to the rotation of the nut 66. Even if the vertical gap between the nut 66 and the spiral spring 65 increases, the other end 672 of the guide tube 67 gradually exits, so that the elastic force of the spiral spring 65 is continuously maintained through the guide tube 67. It extends to the nut 66.

In addition, since the guide tube 67 is formed in a cylindrical shape and surrounds the outer circumferential portion of the spiral spring 65 as described above, lining dust or other foreign matter generated during braking action is wound into the spiral spring 65 which is wound in a plate shape. Inflow is prevented.

And when the driver releases the brake pedal (not shown) and the braking action is released, the leading shoe 30 and the trailing shoe 40 are restored by the elastic restoring force of the restoring spring 80, and as shown in FIG. Likewise, the load is applied to both end portions of the adjuster 60 again, and the disk spring 64 is compressed again to contact the bottom of the insertion hole 613 and one end 631 of the male push rod 63.

At this time, the nut 66 is rotated due to the wear of the linings 31 and 41 so that the other end 632 of the male push rod 63 is slightly at the one end 621 of the second female push rod 62. Since it is in the exited state, the length D3 of the overall adjuster 60 is kept longer than the initial stage, so that the gap between the linings 31 and 41 and the inner peripheral surface of the drum 10 is kept constant.

Therefore, when the lining (31, 41) wear occurs, the length of the adjuster 60 is immediately extended to compensate linearly the gap between the lining (31, 41) and the inner peripheral surface of the drum 10, the next braking action The distance that the wheel cylinder 50 piston (not shown) for contacting the sea linings 31 and 41 to the inner peripheral surface of the drum 10 should be equal to the distance before the linings 31 and 41 wear.

By this operation, even if the drum brake is used for a long time, the same braking response can be felt as in the initial state, thereby improving the reliability of the overall braking system. In addition, the components for rotating the nut 66 is simply made of a spiral spring 65, a guide tube 67, a pair of disk springs 64, etc., and manufacturing cost is also reduced.

As described in detail above, in the drum brake adjuster according to the present invention, a first female push rod and a second female push rod are connected to each other via a male push rod having a nut coupled to an outer circumferential surface thereof. When worn, the nut is immediately rotated by the spiral spring provided at the center of the male push rod, thereby extending the overall length of the adjuster.

Therefore, as soon as lining wear occurs, the overall length of the adjuster is linearly extended, so that the required amount of the wheel cylinder is constant and the braking response of the drum brake is improved. In addition, since the components of the adjuster are simple, the manufacturing cost is reduced, and the guide tube for transmitting the elastic force of the spiral spring to the nut is formed in a cylindrical shape to surround the outer portion of the spiral spring, thereby preventing foreign substances from entering. have.

Claims (2)

The drum 10 rotates with the wheel, and linings 31 and 41 are attached to maintain a constant distance from the inner circumferential surface of the drum 10. The linings 31 and 41 rub against the inner circumferential surface of the drum 10 during braking operation. The outer side of the leading shoe 30, the trailing shoe 40, and the leading shoe 30 coupled to the trailing shoe 30 and the other end is coupled to the trailing shoe 40 to release the braking action. Restoring spring 80, restoring the leading shoe 30 and the trailing shoe 40 so that 31 and 41 maintain a constant distance from the drum 10, the leading shoe 30 and the trailing shoe ( 40, a drum brake having an adjusting device 60 which is coupled between both ends thereof to compensate for the separation distance between the drum 10 and the linings 31 and 41 when the linings 31 and 41 are worn out. , The adjuster 60, One end 611 is coupled to the leading shoe 30 and the first female push rod 61 and the first female push rod 61 having an insertion hole 613 formed at a predetermined depth in the other end 612. The second end of the second end portion 612 and the axial direction spaced apart and the second female push rod 62 is coupled to the trailing shoe 40, the second female push rod 62 and the One end portion 631 is coupled to the insertion hole 613 of the first female push rod 61 in an axial direction so as to connect the first female push rod 61, and the other end thereof is the spiral shaft 632. A mail push rod 63 coupled to one end 621 of the second push rod rod 62 so as to be freely coupled thereto, and a spiral shaft 632 of the mail push rod 63 is formed in the second push rod rod 62. The spiral shaft 632 is gradually removed from one end 621 of the female push rod 62 and the gap between the drum 10 and the drum 10 is compensated by the wear of the linings 31 and 41. The nut 66, which is coupled to the teeth and rotates, one end 651 is fixed on the center of the mail push rod 63 to rotate the nut 66, and the other end 652 is wound to surround the nut 66. The spiral spring 65, which is weaker than the elastic force of the restoring spring 80, and the one end 671 is fixed to the outer circumference of the nut 66 so that the nut 66 is rotated at the same time when the spiral spring 65 is loosened. End portion 672 is wrapped around the outside of the spiral spring 65 by a predetermined interval, but the end of the other end 652 of the spiral spring 65 is axially coupled to the axial direction when the loosening operation of the spiral spring 65 The tubular guide tube 67 which is integrally rotated to rotate the nut 66 and the nut 66 which receives the rotational force through the guide tube 67 are not caused to wear the linings 31 and 41. In the case of the second email push rod (6 2) The other end 612 and the spiral spring 65 side of the first female push rod 61 to prevent the loosening action of the spiral spring 65 by keeping in close contact with one end 621 It is installed on the outer periphery of the male push rod 63 between the ends and elastically biases them in the opposite direction, and its elastic force is weaker than the restoring spring 80 and has a stronger disk spring 64 than the spiral spring 65. Adjusting apparatus for drum brake. The method of claim 1, A coupling part 652 is formed at the end of the other end of the spiral spring 65 and is bent to form a coupling space 653 therein. The other end 672 of the guide tube 67 is provided with a guide groove 673 extending in the axial direction so that the coupling portion 652 is fitted into the play through the coupling space (653). Adjusting device for drum brake.