阅读说明：本技术 带热敏片的新型自调机构总成 (Novel self-adjusting mechanism assembly with thermosensitive plate ) 是由 黄东方 胡凯 汪永胜 黄伟杰 朱子亨 黄国兴 凌利峰 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种带热敏片的自调机构总成。自调棘轮开设有通孔,自调螺杆穿过自调棘轮通孔后活动套入自调螺套,自调螺杆和自调棘轮的通孔之间通过螺纹连接,自调棘轮和自调螺套之间设置有热敏片,自调棘轮用于和拨板配合啮合连接；同时自调螺杆和自调螺套外套装上回位弹簧,同时上回位弹簧拉紧装配在前置制动蹄总成和后置制动蹄总成的装配孔内。本发明对减少占用空间且结构简单,避免因为自调机构与轮缸间距小、上回位弹簧与轮缸在制动过程中相对摩擦、弹簧断裂产生拖磨及制动失效等问题,解决热过调带来的摩擦片磨损异常问题,提高领从蹄式鼓式制动器的稳定性和可靠性。(The invention discloses a self-adjusting mechanism assembly with a thermosensitive plate. The self-adjusting ratchet wheel is provided with a through hole, the self-adjusting screw rod is movably sleeved into the self-adjusting screw sleeve after penetrating through the self-adjusting ratchet wheel through hole, the self-adjusting screw rod is connected with the through hole of the self-adjusting ratchet wheel through threads, a heat-sensitive sheet is arranged between the self-adjusting ratchet wheel and the self-adjusting screw sleeve, and the self-adjusting ratchet wheel is used for being in meshing connection with the shifting plate in a matching way; and meanwhile, return springs are sleeved outside the self-adjusting screw rods and the self-adjusting screw sleeves, and the upper return springs are tensioned and assembled in assembly holes of the front brake shoe assembly and the rear brake shoe assembly. The invention has the advantages of reducing the occupied space and simple structure, avoiding the problems of drag grinding, brake failure and the like caused by the relative friction between the self-adjusting mechanism and the wheel cylinder in the braking process, the breakage of the spring and the like due to the small distance between the self-adjusting mechanism and the wheel cylinder, solving the abnormal abrasion problem of the friction plate caused by hot over-adjustment and improving the stability and the reliability of the leading shoe type drum brake.)

1. The utility model provides a take self-modulation mechanism assembly of heat-sensitive piece which characterized in that: the self-regulating mechanism assembly comprises a self-regulating screw rod (1), a self-regulating screw sleeve (4) and an upper return spring (3), a through hole is formed in a self-regulating ratchet wheel (2), one end of the self-regulating screw rod (1) penetrates through the through hole of the self-regulating ratchet wheel (2) and then is movably sleeved into one end of the self-regulating screw sleeve (4), the other end of the self-regulating screw rod (1) is connected with a front brake assembly (6), the other end of the self-regulating screw sleeve (4) is connected with a rear brake shoe assembly (8), the through holes of the self-regulating screw rod (1) and the self-regulating ratchet wheel (2) are connected through threads, a heat sensitive sheet (14) is arranged between the self-regulating ratchet wheel (2) and the self-regulating screw sleeve (4), and the self-regulating ratchet wheel (2) is used for being matched, meshed and connected with a shifting plate (9); meanwhile, return springs (3) are sleeved outside the self-adjusting screw rods (1) and the self-adjusting screw sleeves (4), and meanwhile, the upper return springs (3) are tensioned and assembled in assembly holes of the front brake shoe assembly (6) and the rear brake shoe assembly (8).

2. The self-adjusting mechanism assembly with the heat sensitive sheet as claimed in claim 1, wherein:

the front brake shoe assembly (6) and the rear brake shoe assembly (8) are provided with assembly holes, and two ends of the upper return spring (3) are respectively hooked in the assembly holes of the front brake shoe assembly (6) and the rear brake shoe assembly (8) and are tensioned and assembled.

3. The self-adjusting mechanism assembly with the heat sensitive sheet as claimed in claim 1, wherein:

the heat-sensitive sheet (14) is in a V-shaped sheet shape, a through hole is formed in the middle of each of two petals of the V-shaped sheet (14) and is used for the self-adjusting screw rod (1) to penetrate through, and the two petals of the V-shaped sheet (14) have different thermal expansion coefficients; one valve of the V-shaped piece of the heat-sensitive piece (14) is made of a material with a higher expansion coefficient and is in contact connection with the self-regulating ratchet (2), and the other valve of the V-shaped piece of the heat-sensitive piece (14) is made of a material with a lower expansion coefficient and is fixedly connected with the self-regulating thread sleeve (4).

4. The self-adjusting mechanism assembly with the heat sensitive sheet as claimed in claim 3, wherein:

the end face of the self-adjusting threaded sleeve (4) close to the thermosensitive plate (14) is provided with a clamping groove opening for assembling the thermosensitive plate (14), one valve of the thermosensitive plate (14) close to the self-adjusting threaded sleeve (4) is provided with a bulge, and the bulge is embedded in the clamping groove opening, so that the thermosensitive plate (14) is buckled on the end face of the self-adjusting threaded sleeve (4).

5. The self-adjusting mechanism assembly with the heat sensitive sheet as claimed in claim 1, wherein:

self-modulation screw rod (1) be equipped with a lug (A) at the tip of being connected with leading brake assembly (6), dial board (9) middle part articulated installation on leading brake shoe assembly (6), dial board (9) one end to self-modulation ratchet (2) extend and with self-modulation ratchet (2) meshing connection formation ratchet connect, dial board (9) other end and be equipped with the kink that extends to lug (A), lug (A) is used for blockking the rotational position of dialling the spacing dial board (9) of board (9) kink.

6. The self-adjusting mechanism assembly with the heat-sensitive sheet as claimed in claim 1 or 5, wherein:

the shifting plate (9) is hinged and installed on a front brake tendon (12) of the front brake shoe assembly (6) through a cylindrical pin (10), and is elastically connected with the lower part of the front brake tendon (12) through a tensioning spring (11).

7. The self-adjusting mechanism assembly with the heat sensitive sheet as claimed in claim 1, wherein:

the other ends of the self-adjusting screw rod (1) and the self-adjusting screw sleeve (4) are provided with two sunken clamping groove openings, the clamping groove opening at the other end of the self-adjusting screw rod (1) is clamped and connected between the clamping grooves of the rear brake shoe assembly (8), and the clamping groove opening at the other end of the self-adjusting screw sleeve (4) is clamped and connected between the clamping grooves of the front brake shoe assembly (6).

8. The self-adjusting mechanism assembly with the heat sensitive sheet as claimed in claim 1, wherein:

the upper return spring (3) is arranged outside the self-adjusting screw rod (1) and the self-adjusting threaded sleeve (4) in a winding manner.

9. The self-adjusting mechanism assembly with the heat sensitive sheet as claimed in claim 1, wherein:

the self-adjusting screw rod (1) and the self-adjusting screw sleeve (4) are arranged by relatively penetrating the upper return spring (3) from two ends of the upper return spring (3).

Technical Field

The invention relates to a leading shoe type drum brake triggered by hydraulic pressure, in particular to a self-adjusting mechanism assembly with a heat-sensitive sheet.

Background

The hydraulic leading shoe drum brake is mainly used on a car or a pick-up truck, the car is characterized by large amount, the brake of the pick-up truck is relatively large, and the brake is required to be stable in structure, high in reliability and stable in braking.

Before the whole vehicle is assembled, parts of the brake are required to be assembled, transported, equipped with the axle and the brake drum, and the brake is inevitably bumpy in the process of transporting and assembling the axle. Vibration, collision and the like, the two side shoes of the traditional leading shoe drum brake can slide to different degrees:

firstly, the upper return spring is interfered with a wheel cylinder body when the brake is over-shoe sliding, the springs are abraded and broken due to mutual friction in the braking process, the brake shoe cannot return, the shoe and the brake drum are dragged and ground, the friction plate is abnormally abraded, and the service life of the friction plate is greatly shortened;

secondly, the brake over-shoe sliding can cause the interference between an upper return spring and a wheel cylinder shield, the wheel cylinder shield can be guided to break, dust enters a cylinder body, and finally the brake failure is caused;

in the braking process, because the brake drum and the brake are closed spaces and the heat dissipation is poor, the clearance between the brake drum and the brake shoe is too large, the self-adjusting mechanism is adjusted more, the clearance between the brake drum and the brake shoe is small, the brake shoe is dragged and abraded, the friction plate is abraded in advance, and the service life is shortened;

from the market and axle factory feedback, the excessive slipping of the shoes is common, and the situation causes complaints of customers to different degrees, so that the safe space between the return spring and the cylinder and the thermal overshoot are increased and are not easily relieved when the brake is designed.

Disclosure of Invention

In order to solve the problem that the safety space between an upper return spring and a wheel cylinder is increased in the brake in the prior art, the invention aims to provide a self-adjusting mechanism assembly with a heat-sensitive sheet, so that the self-adjusting mechanism is sleeved in the upper return spring, the distance between the upper return spring and the wheel cylinder assembly is greatly increased, the problems of breakage of the upper return spring, breakage of a wheel cylinder shield and the like caused by excessive sliding of a shoe are solved, meanwhile, the structure of the heat-sensitive sheet is increased, the problem of abnormal abrasion of the friction sheet caused by the fact that the gap between a brake drum and related parts of the brake is increased when the brake drum and the related parts of the brake drum pass through the shoe drum is solved, and the stability and the reliability of the brake drum brake are improved.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the self-regulating mechanism assembly comprises a self-regulating screw rod, a self-regulating screw sleeve and an upper return spring, the self-regulating ratchet wheel is provided with a through hole, one end of the self-regulating screw rod penetrates through the through hole of the self-regulating ratchet wheel and then is movably sleeved into one end of the self-regulating screw sleeve, the other end of the self-regulating screw rod is connected with the front brake assembly, the other end of the self-regulating screw sleeve is connected with the rear brake shoe assembly, the self-regulating screw rod is connected with the through hole of the self-regulating ratchet wheel through threads, a heat-sensitive sheet is arranged between the self-regulating ratchet wheel and the self-regulating screw sleeve, and the self-regulating ratchet wheel is used for being in matched meshed connection with the shifting plate; and meanwhile, return springs are sleeved outside the self-adjusting screw rods and the self-adjusting screw sleeves, and the upper return springs are tensioned and assembled in assembly holes of the front brake shoe assembly and the rear brake shoe assembly.

The front brake shoe assembly and the rear brake shoe assembly are provided with assembly holes, and two ends of the upper return spring are respectively hooked in the assembly holes of the front brake shoe assembly and the rear brake shoe assembly and are tensioned and assembled.

The heat-sensitive sheet is in a V-shaped sheet shape, a through hole is formed in the middle of each of two petals of the V-shaped sheet of the heat-sensitive sheet and is used for the self-adjusting screw to penetrate through, and the two petals of the V-shaped sheet of the heat-sensitive sheet have different thermal expansion coefficients; one valve of the V-shaped heat-sensitive piece is made of a material with a higher expansion coefficient and is in contact connection with the self-regulating ratchet wheel, and the other valve of the V-shaped heat-sensitive piece is made of a material with a lower expansion coefficient and is fixedly connected with the self-regulating screw sleeve.

The self-adjusting screw sleeve is provided with a clamping groove opening for assembling the heat-sensitive sheet on the end surface close to the heat-sensitive sheet, the heat-sensitive sheet is provided with a bulge on a flap close to the self-adjusting screw sleeve, and the bulge is embedded in the clamping groove opening, so that the heat-sensitive sheet is buckled on the end surface of the self-adjusting screw sleeve.

The self-adjusting screw rod is provided with a convex block at the end part connected with the front brake assembly, the middle part of the shifting plate is hinged on the front brake shoe assembly, one end of the shifting plate extends towards the self-adjusting ratchet wheel and is meshed with the self-adjusting ratchet wheel to form ratchet connection, the other end of the shifting plate is provided with a bending part extending towards the convex block, and the convex block is used for blocking the rotating position of the shifting plate limited by the bending part of the shifting plate.

The shifting plate is hinged to a front brake tendon of the front brake shoe assembly through a cylindrical pin and is elastically connected with the lower part of the front brake tendon through a tensioning spring.

The other ends of the self-adjusting screw rod and the self-adjusting screw sleeve are provided with two sunken clamping groove openings, the clamping groove opening at the other end of the self-adjusting screw rod is clamped and connected between the clamping grooves of the rear brake shoe assembly, and the clamping groove opening at the other end of the self-adjusting screw sleeve is clamped and connected between the clamping grooves of the rear brake shoe assembly.

The upper return spring is arranged outside the self-adjusting screw rod and the self-adjusting threaded sleeve in a winding mode.

The self-adjusting screw rod and the self-adjusting screw sleeve penetrate into the upper return spring from two ends of the upper return spring oppositely.

The invention reduces the occupied space of brake parts, has simple structure, avoids the problems of drag grinding, brake failure and the like caused by the breakage of the spring due to the relative friction between the upper return spring and the wheel cylinder in the braking process because the distance between the self-adjusting mechanism and the wheel cylinder is small, can solve the problem of abnormal friction plate abrasion caused by thermal overshoot by adding the heat-sensitive plate, and improves the stability and reliability of the leading shoe type drum brake.

The invention has the beneficial effects that:

the invention realizes that the self-adjusting mechanism is sleeved in the upper return spring, avoids the space between the self-adjusting mechanism and the wheel cylinder assembly which is compact, then the upper return spring part is added, avoids the problems of return spring fracture, wheel cylinder shield fracture and the like caused by excessive sliding of a shoe, increases the thermosensitive plate, solves the problem of abnormal abrasion of the friction plate caused by the increase of the clearance of the brake drum and the related parts of the brake due to the heat of the brake drum, and improves the stability and the reliability of the leading shoe type drum brake

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a cross-sectional view of fig. 3.

FIG. 3 is a brake assembly illustration.

Fig. 4 is an exploded view of the present invention.

Fig. 5 is a structural view of a thermal sheet.

Fig. 6 is a schematic view of an operating state after deformation of the heat sensitive sheet.

In the figure: the self-adjusting brake comprises a self-adjusting screw rod 1, a self-adjusting ratchet wheel 2, an upper return spring 3, a self-adjusting screw sleeve 4, a brake drum 5, a front brake shoe assembly 6, a brake wheel cylinder assembly 7, a rear brake shoe assembly 8, a shifting plate 9, a cylindrical pin 10, a tensioning spring 11, a front brake shoe rib 12, a rear brake shoe rib 13 and a heat-sensitive sheet 14. .

In the figure: the self-adjusting brake comprises a self-adjusting screw rod 1, a self-adjusting ratchet wheel 2, an upper return spring 3, a self-adjusting screw sleeve 4, a brake drum 5, a front brake shoe assembly 6, a brake wheel cylinder assembly 7, a rear brake shoe assembly 8, a shifting plate 9, a cylindrical pin 10, a tensioning spring 11, a front brake shoe rib 12, a rear brake shoe rib 13, a heat-sensitive sheet 14 and a convex block A.

Detailed Description

The invention is further described with reference to the accompanying drawings and the detailed description.

As shown in fig. 1 and 4, the self-adjusting mechanism assembly comprises a self-adjusting screw rod 1, a self-adjusting threaded sleeve 4 and an upper return spring 3, a through hole is formed in a self-adjusting ratchet wheel 2, the peripheral surface of the self-adjusting ratchet wheel 2 is of a ratchet wheel structure, one end of the self-adjusting screw rod 1 penetrates through the through hole of the self-adjusting ratchet wheel 2 and then is movably sleeved into one end of the self-adjusting threaded sleeve 4, the self-adjusting screw rod 1 and the self-adjusting threaded sleeve 4 are not in threaded connection, the other end of the self-adjusting screw rod 1 is clamped and connected to a front brake assembly 6, the other end of the self-adjusting threaded sleeve 4 is clamped and connected between grooves of a rear brake shoe assembly 8, the through holes of the self-adjusting screw rod 1 and the self-adjusting ratchet wheel 2 are in threaded connection, a thermosensitive plate 14 is arranged between the self-adjusting ratchet wheel 2 and the self-adjusting threaded sleeve 4, and the self-adjusting ratchet wheel 2 is used for being engaged and connected with a shifting plate 9; meanwhile, return springs 3 are sleeved outside the self-adjusting screw rods 1 and the self-adjusting screw sleeves 4, and the upper return springs 3 are tensioned and assembled in assembly holes of the front brake shoe assembly 6 and the rear brake shoe assembly 8.

The front brake shoe assembly 6 and the rear brake shoe assembly 8 are provided with assembly holes, and two ends of the upper return spring 3 are respectively hooked in the assembly holes of the front brake shoe assembly 6 and the rear brake shoe assembly 8 and are tensioned and assembled.

As shown in fig. 2 and 3, the brake drum 5, the front brake shoe assembly 6, and the rear brake shoe assembly 8 are all disposed on the brake base plate, the front brake shoe assembly 6 includes a front brake tendon 12, and the rear brake shoe assembly 8 includes a rear brake tendon 13. A brake wheel cylinder assembly 7 is arranged between the front brake shoe assembly 6 and the rear brake shoe assembly 8, the brake wheel cylinder assembly 7 is fixedly arranged on the brake bottom plate, and two ends of the brake wheel cylinder assembly are respectively connected with a front brake tendon 12 and a rear brake tendon 13.

As shown in fig. 5, the heat-sensitive sheet 14 is in a V-shaped sheet shape, the bottoms of the two petals of the V-shaped sheet of the heat-sensitive sheet 14 are connected together, a through hole is formed in the middle of each of the two petals of the V-shaped sheet of the heat-sensitive sheet 14 and is used for the self-adjusting screw 1 to pass through, and the thermal expansion coefficients of the two petals of the V-shaped sheet of the heat-sensitive sheet 14 are different; one valve of the heat-sensitive sheet 14V-shaped sheet is made of a material with a higher expansion coefficient and is in contact connection with the self-regulating ratchet 2, and the other valve of the heat-sensitive sheet 14V-shaped sheet is made of a material with a lower expansion coefficient and is fixedly connected with the self-regulating thread sleeve 4.

The material of the V-shaped thermosensitive plate close to the 2 petals of the self-regulating ratchet wheel is a high expansion coefficient material, and the material of the V-shaped thermosensitive plate close to the 4 petals of the self-regulating screw sleeve is a low expansion coefficient material.

Under the natural normal temperature state, two petals of the heat-sensitive piece 14V-shaped piece are folded and attached tightly; in a heated state, the two lobes of the V-shaped piece of the heat sensitive piece 14 are separated and opened.

The end face of the self-adjusting threaded sleeve 4 close to the heat-sensitive sheet 14 is provided with a clamping groove opening for assembling the heat-sensitive sheet 14, the heat-sensitive sheet 14 is provided with a bulge on a part close to the self-adjusting threaded sleeve 4, and the bulge is embedded in the clamping groove opening, so that the heat-sensitive sheet 14 is fixedly connected with the end face of the self-adjusting threaded sleeve 4 in a buckling manner, and the self-adjusting threaded sleeve 4 and the heat-sensitive sheet 14 are kept fixed.

The heat sensitive sheet 14 is heated by heat transfer after the working temperature of the brake rises, the two petals deform and open after the heat sensitive sheet 14 reaches a preset temperature threshold, and the distance between the two petals is increased.

The function of heat-sensitive piece is excessive regulation when preventing to rise along with the stopper temperature, and when the brake drum is under the high temperature condition, produce the deformation, lead to the shoe drum clearance to be greater than the settlement clearance value, the heat-sensitive piece can open along with the rise of temperature this moment, promote self-modulation mechanism assembly motion, compensate the shoe drum clearance value because of warping the production, and the opening power of heat-sensitive piece is greater than the pulling force that dials the plate spring and act on and dial the board simultaneously, so dial the board and can't dial the clearance ratchet, when the temperature descends, the heat-sensitive piece resets to keep the shoe drum clearance of settlement.

As shown in fig. 6, the V-shaped heat-sensitive plate moves toward the self-adjusting ratchet 2 when a thermal expansion coefficient of a part of the heat-sensitive plate close to the self-adjusting ratchet 2 is higher, and then the self-adjusting ratchet 2 and the self-adjusting screw 1 are pushed to move integrally toward the direction close to the front brake shoe assembly 6, and then the convex block on the self-adjusting screw 1 is driven to move toward the outer side, i.e., toward one side of the friction plate, and the shifting plate 9 is pushed to rotate toward the reverse gap adjusting direction, so that the gap adjustment is reduced to eliminate the increased gap of the overheated shoe drum, the self-adjusting mechanism works more stably, and the problem of abnormal abrasion of the friction plate caused by the increased gap of the shoe drum heated by the brake drum and related parts of the brake is solved.

The end part of the self-adjusting screw 1 connected with the front brake assembly 6 is provided with a convex block A, the middle part of a shifting plate 9 is hinged on the front brake shoe assembly 6, one end of the shifting plate 9 extends towards the self-adjusting ratchet 2 and is meshed and connected with the self-adjusting ratchet 2 to form ratchet connection, in the figure 3, one end of the shifting plate 9 is allowed to move downwards to drive the self-adjusting ratchet 2 to rotate, and the self-adjusting ratchet 2 and the self-adjusting screw 1 are driven to axially approach together through the threaded connection of the self-adjusting ratchet 2 and the self-adjusting screw 1. The other end of the shifting plate 9 is provided with a bending part extending towards the convex block A, the convex block A is in contact connection with the bending part of the shifting plate 9, and the convex block A is used for blocking the rotating position of the shifting plate 9 limited by the bending part of the shifting plate 9, namely blocking the clockwise motion of the shifting plate 9 in figure 3.

As shown in fig. 2 and 3, the pulling plate 9 is hinged to a front brake shoe 12 of the front brake shoe assembly 6 through a cylindrical pin 10, and is elastically connected to a lower portion of the front brake shoe 12 through a tension spring 11.

As shown in fig. 1, two recessed slot openings are formed at the other ends of the self-adjusting screw rod 1 and the self-adjusting screw sleeve 4, the slot opening at the other end of the self-adjusting screw rod 1 is connected to the front brake shoe assembly 6 in a clamping manner, a projection a is arranged on the arm part on one side of the slot opening, and the slot opening at the other end of the self-adjusting screw sleeve 4 is connected between the slots of the rear brake shoe assembly 8 in a clamping manner.

In specific implementation, the upper return spring 3 is arranged outside the self-adjusting screw rod 1 and the self-adjusting threaded sleeve 4 in a winding manner. The self-adjusting screw rod 1 and the self-adjusting screw sleeve 4 are oppositely arranged by penetrating the upper return spring 3 from two ends of the upper return spring 3.

The brake wheel cylinder assembly 7 is filled with hydraulic pressure to push a front brake shoe assembly 6 and a rear brake shoe assembly 8 to open, when the front brake shoe assembly 6 and the rear brake shoe assembly 8 open to a pressure-down brake drum 5, the spring force of an upper return spring 3 is smaller than the hydraulic driving force, three parts of a self-regulating ratchet wheel 2, a self-regulating screw rod 1 and a self-regulating screw sleeve 4 are not stressed, meanwhile, a shifting plate 9 is subjected to the F-direction force of a shifting plate tensioning spring 11 to rotate around the center C of a cylindrical pin 10 in the B direction in the circumferential direction, because the self-regulating ratchet wheel 2, the self-regulating screw rod 1 and the self-regulating screw sleeve 4 are not subjected to the clamping force of the upper return spring 3, the shifting plate 9 rotates to drive the self-regulating ratchet wheel 2 to rotate around the self-regulating screw rod 1, the self-regulating ratchet wheel 2 is in threaded fit with the self-regulating screw rod 1, the self-regulating screw sleeve 4 is jacked open, the size of the distance L between the self-regulating screw sleeve 4 and the self-regulating screw rod 1 is increased, the brake hydraulic pressure is removed, the front brake shoe assembly 6 and the rear brake shoe assembly 8 return under the return force of the upper return spring 3, the self-regulating ratchet wheel 2, the self-regulating screw rod 1, the self-regulating screw sleeve and the clamping force of the upper return spring 3 return to a clamping state, and meanwhile, the brake shoes are opened for a certain distance, and self-regulation is completed.

In the braking process of the brake shown in fig. 2 and 3, as the brake drum 5 and the brake are closed spaces and the heat dissipation is poor, the gaps between the brake drum and the front brake shoe assembly 6 and the rear brake shoe assembly 8 are enlarged, the self-adjusting mechanism is adjusted more, the L size is changed greatly, after the braking is finished, the gap between the brake drum is reduced, the brake shoe drags and grinds the brake drum, the friction plates are worn in advance, the service life is shortened, the thermosensitive plate is automatically deformed and opened when the temperature of the brake reaches a certain temperature, the L size is enlarged, the self-adjusting ratchet wheel 2 and the self-adjusting screw rod 1 are pushed to move outwards, the shifting plate 9 is driven to rotate in the opposite direction of the gap adjustment, the self-adjusting mechanism works more stably, and the problem of abnormal abrasion of the friction plates caused by the fact that the gaps between the brake drum and related parts of the brake are heated and the brake drum are enlarged is solved. The enlarged portion of the dimension L is eliminated by the clamping force of the upper return spring 3 after the braking is completed.

When the vehicle is braked in a service mode, a vehicle pedal is stepped down, the support of the brake wheel cylinder assembly 7 moves towards two sides and acts on the front brake shoe rib 12 and the rear brake shoe rib 13, so that the front brake shoe assembly 6 and the rear brake shoe assembly 8 are opened and pressed on the brake drum 5 to generate braking.

The brake device can reduce the occupied space of brake parts, has a simple structure, avoids the problems of drag grinding, brake failure and the like caused by the breakage of the spring due to the relative friction between the upper return spring and the wheel cylinder in the braking process because the distance between the self-adjusting mechanism and the wheel cylinder is small, and improves the stability and reliability of the leading shoe type drum brake.

The forward brake tendon 12 is a component of the forward brake shoe assembly 3 and the rear brake tendon 14 is a component of the rear brake shoe assembly 8.

Therefore, the self-adjusting mechanism assembly with the heat-sensitive sheet disclosed by the invention has the advantages that the self-adjusting ratchet wheel, the self-adjusting screw rod, the self-adjusting screw sleeve and the upper return spring are combined together, the problems of drag wear, brake failure and the like caused by the fact that the upper return spring and the wheel cylinder are relatively rubbed in the braking process due to insufficient space position between the self-adjusting mechanism and the wheel cylinder assembly, the spring is broken and the like are solved, meanwhile, the heat-sensitive sheet is added, the abnormal abrasion problem of a friction plate caused by the fact that the gap between a brake drum and related parts of a brake is increased due to heat of the brake drum is solved, and the stability and the reliability of a leading shoe type drum brake are improved.

The above examples are illustrative of the present invention and are not intended to be limiting, and any simple modification of the present invention is within the scope of the present invention.