CN102897633B - Elevator rolling guide shoe with brake function - Google Patents

Abstract

The invention provides an elevator rolling guide shoe with braking function. The device has a rolling guide wheel mechanism, a hydraulic actuator and a stop mechanism. The three guide wheels of the rolling guide wheel mechanism are closely attached to the three working surfaces of the T-shaped guide rail to limit the movement of the elevator car in the horizontal direction; the hydraulic actuator is connected with each guide wheel of the guide shoe, and can be used according to The detected running state of the elevator determines whether to apply pressure to the guide wheel; the stop mechanism is integrated inside the guide wheel. , so that the guide wheel hugs the guide rail to realize emergency braking, wherein the mechanism is composed of the following parts: guide shoe base, long connecting rod, main and secondary swing rods, brake base plate, hydraulic wheel cylinder, brake shoe, brake Brake pads and brake drums covered with wear-resistant rubber.

Description

Elevator rolling guide shoe with braking function

technical field

The invention relates to a rolling guide shoe for an elevator, in particular to an elevator rolling guide shoe with a braking function, which is stopped by the guide wheel of the elevator guide shoe and is connected to the T-shaped guide rail of the elevator under the action of the pressing force provided by the actuator. Hold to realize emergency braking of the elevator car when the elevator stalls.

Background technique

Generally speaking, the rolling guide shoe is between the elevator guide rail and the car, which can make the car move up and down along the guide rail, and replace the sliding friction with rolling friction, so as to reduce the vibration and noise during the operation of the elevator and improve the riding comfort. The comfortable passive vibration reduction device does not have the function of emergency braking of the elevator car. And present elevator is mainly to make elevator emergency brake on guide rail when overspeed, running out of control or suspension device break through speed limiter safety gear system. However, with the increasing popularity of elevators, people's requirements for elevator safety and comfort continue to improve, and a safety device that is different from the speed governor safety gear system has been developed.

As the prior art, for example, the invention patent owned by Xizi Otis Elevator Co., Ltd. is known: an integrated safety device for elevators. The invention provides an elevator integrated safety device, which integrates a plurality of scattered components and arranges them at the bottom of the elevator car. The features include: a safety gear device, and a lifting rod connecting the guide device and the safety gear device. It has the functions of overspeed governor, safety gear and safety gear pulling mechanism, guide shoe guidance and overspeed protection, and saves the speed governor wire rope, overspeed governor tensioning device and safety gear pulling mechanism.

According to the above technology, the guide device is composed of three rollers, the outer edges of the rollers are closely attached to the three guide surfaces of the elevator guide rails, and roll up and down along the guide rail guide surfaces to play the guiding role of the elevator; the safety gear device includes a safety gear and a lifting rod, the lifting rod is a bent rod or a rack, the lifting rod is connected between the ratchet and the safety gear, and when the pulling rod is pulled to a certain extent, the safety gear can clamp the guide rail and brake the elevator, thereby Realize the overspeed protection function of the elevator.

Patent Document 1: Elevator Integrated Safety Device, Patent No. 200810062859.X

As the prior art, for example, the invention patent owned by Hitachi Manufacturing Co., Ltd. of Japan is known: an elevator safety device and an elevator with the elevator safety device. The invention provides an elevator safety device, which has a speed regulating mechanism, a lifting switch mechanism and a lifting mechanism, wherein the speed regulating mechanism is arranged opposite to the guide rails arranged on the walls of the lift passage on both sides of the elevator car along the running direction of the elevator car , and contact with the guide rail to detect the running speed of the elevator car; the lifting switch mechanism operates when the speed exceeds the specified speed through the speed regulating mechanism; the lifting mechanism hugs the guide rail and Lift the lifting rod; the lifting rod is connected with the safety gear, and the safety gear clamps the guide rail and brakes the elevator, so as to realize the overspeed protection function of the elevator. the

According to the above-mentioned technology, the lifting mechanism is composed of the following parts: a rod supported so as to be able to swing around the rod rotation axis as a rotation center, a shoe-shaped member clamping a guide rail provided at the other end of the rod, and the A clamping member of the shoe, a clamping rotating shaft rotatably supporting the clamping member, and a clamping spring providing a rotational force to the clamping member.

Patent Document 2: Elevator Safety Device and Elevator with the Elevator Safety Device, Patent No. 200610142423.2

As the prior art, for example, Feng Yonghui's doctoral dissertation: Research on Active Control of High-Speed Elevator Horizontal Vibration is known. This paper provides an elevator device, creatively applies the hydraulic actuator to the active control of the horizontal vibration of the elevator, uses the hydraulic actuator as the actuator, and designs a hydraulic active guide shoe. Among them, the hydraulic cylinder is used as the actuator, installed between the guide rail bracket and the supporting rocker arm of the guide wheel, and replaces the damping spring in the passive guide shoe.

According to the above technology, each hydraulic oil cylinder in the elevator device is connected with two hydraulic valves, one of which is an oil inlet valve and the other is an oil return valve, and the oil pressure in the oil cylinder is controlled by opening and closing the hydraulic valve. to control. The controller reads the oil pressure value in the oil cylinder through the pressure sensor, executes the control strategy, gives control instructions according to the pressure value and the attitude of the elevator car, and opens or closes the hydraulic valve. The hydraulic cylinder then drives the supporting rocker arm of the guide wheel to actively adjust the interaction force between the guide wheel and the elevator guide rail, and actively eliminate the vibration caused by the unevenness of the elevator guide rail.

Reference 3: Feng Yonghui. Elevator device and elevator device guide device [PhD dissertation]. Shanghai: Shanghai Jiaotong University, 2008.

Among the above three existing technologies, the first two patents are about elevator safety, mainly improving the original speed limiter safety gear protection system of the elevator, and canceling the speed limiter system. The speed of the elevator car is detected by the rotation of the wheel in contact with the guide rail itself, which simplifies the original safety gear protection system of the speed limiter; the third document is about elevator vibration reduction, and the hydraulic actuator is applied to the horizontal vibration of the elevator In the active control, the hydraulic pressure is used to improve the posture state between the elevator car and the guide rail, and the passive vibration reduction is changed to the active vibration reduction. The innovation is to combine the hydraulic actuator to produce a large displacement under a relatively small structural size And the characteristics of large force can realize rapid and effective control.

However, the first two patents still retain the safety gear system. With the current increase in the popularity of elevators, the probability of safety gear not being regularly maintained is also greatly increased, and the problem of failure of the elevator braking mechanism still exists, so it cannot be fundamentally solved. To solve the problem of elevator safety, in addition, the wheels used to detect the speed of the elevator car and contact the guide rail have some functional overlap with the elevator rolling guide shoes, and the two will interfere with each other, resulting in the possibility of both functions The descent, which affects the vibration reduction and emergency braking of the elevator car, also brings maintenance problems. The third patent obviously does not have the function of emergency braking of the elevator car. To some extent, although the hydraulic cylinder can drive the supporting rocker arm of the guide wheel to rotate around the axis of rotation of the rocker arm, to provide a gap between the guide wheel and the guide rail. However, in addition to the friction surface of the guide wheel and the guide rail, there is also the friction surface of the guide wheel and the rotation axis of the guide wheel between the guide wheel and the guide rail. The compression force provided by the hydraulic cylinder is not enough to stop the guide wheel from rotating, that is, This device lacks a practicable guide wheel stopping mechanism.

After searching the Chinese patents, no inventions related to the emergency braking of the elevator car can be found by the elevator rolling guide shoe.

Contents of the invention

Proposed in view of the practical problems existing in the above-mentioned prior art, the object of the present invention is to provide a rolling guide shoe of an elevator with a braking function, which has the function of effectively making the elevator car stall when the elevator car stalls. Action mechanism for emergency braking.

In order to achieve the above object, the idea of the present invention is that the present invention includes: a rolling guide wheel mechanism, a hydraulic actuator and a stop mechanism, and the three guide wheels of the rolling guide wheel mechanism are closely attached to the three working surfaces of the T-shaped guide rail , to limit the movement of the elevator car in the horizontal direction; the hydraulic actuator is connected with each guide wheel of the guide shoe, and can actively adjust the required driving force according to the detected running state of the elevator; the braking mechanism is integrated in the guide Inside the wheel, when the elevator stalls, the stop mechanism acts to stop the guide wheel from rotating, and cooperates with the pressing force provided by the hydraulic actuator to make the guide wheel hug the guide rail to achieve emergency braking.

According to above-mentioned inventive concept, the present invention adopts following technical scheme:

An elevator rolling guide shoe with braking function, comprising: a rolling guide wheel mechanism, a hydraulic actuator and a stop mechanism, characterized in that: the three guide wheels of the rolling guide wheel mechanism are closely attached to the three working parts of the guide rail. On the surface, the hydraulic actuator is connected to each guide wheel of the rolling guide wheel mechanism, and the stop mechanism is integrated inside the guide wheel; Make the guide wheel stop rotating, cooperate with the pressing force provided by the hydraulic actuator, make the guide wheel hug the guide rail to realize emergency stop.

The elevator rolling guide shoe with braking function is characterized in that: the rolling guide wheel mechanism includes a brake drum, wear-resistant rubber, a guide shoe base, a main swing rod, a secondary swing rod, a limit spring, The first connects the long rod, in which the outer layer of the brake drum is inlaid with a layer of wear-resistant rubber to form a guide wheel. The lower ends of the main and secondary swing rods are hinged with the base of the guide shoe. A rotating shaft is installed between the swing rods, and the brake drum is installed on the rotating shaft. The first connecting long rod passes through the main swing rod on the side of the guide wheel and is connected with the fixed vertical column of the guide shoe base. The limit spring is installed on the The first connects the outer end of the long rod.

The elevator rolling guide shoe with braking function is characterized in that: the hydraulic actuator includes a driving hydraulic cylinder, a driving hydraulic cylinder mounting plate, a second and a third connecting rod, wherein the second and the third connecting rod are long The rod passes through the main swing rod and is connected to the fixed vertical column of the guide shoe base, the driving hydraulic cylinder mounting plate is fixed on the second and third connecting long rods by bolts, and the driving hydraulic cylinder is fixed on the driving hydraulic cylinder mounting plate, The outer end of the piston rod driving the hydraulic cylinder is hinged with the main swing rod.

The elevator rolling guide shoe with braking function is characterized in that: the stop mechanism includes a brake base plate, a brake pad, a brake shoe, a support pin, and a hydraulic cylinder, wherein the brake drum and The brake base plate is fastened, and a brake shoe is arranged on the left and right sides of the brake base plate, and both of them are parallel to the brake base plate. The support pin at the lower part of the movable base plate swings, the brake pads are fixed on the brake shoes, and the hydraulic cylinder is located on the upper part of the brake base plate, which conflicts with the upper end points of the two brake shoes; an up and down return spring is installed between the two brake shoes (24, 31) and brake shoe clearance adjustment spring (27).

Compared with the prior art, the present invention has the following obvious outstanding substantive features and significant technical progress: mainly the function of the guide shoe is expanded, and the safety gear system can be omitted at the same time, so that the guide shoe integrates the functions of guidance and emergency braking all in one. According to the needs of elevator operation, the function of the guide shoes can be changed in time, so there will be no mutual interference.

Description of drawings

Fig. 1 is an overall perspective view of an elevator guide shoe device related to an embodiment of the present invention;

Fig. 2 is a perspective view of the working conditions of the forward guide wheel of the elevator guide shoe involved in an embodiment of the present invention;

Fig. 3, 4, represent the exploded view of the guide wheel that contacts with elevator guide rail among Fig. 2;

Fig. 5, 6, represent among Fig. 3, promptly described patent guide wheel inside contained concrete composition figure of the stopping mechanism;

7 and 8 are diagrams showing the assembly relation of the guide wheel of the guide shoe and the swing rod supporting the guide wheel according to an embodiment of the present invention.

Detailed ways

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Embodiment one:

Referring to Figures 1 to 3, the elevator rolling guide shoe with braking function includes: a rolling guide wheel mechanism (I), a hydraulic actuator (II) and a stop mechanism (III), and is characterized in that: the rolling guide The three guide wheels (50) of the wheel mechanism (I) are closely attached to the three working surfaces of the guide rail (1), and the hydraulic actuator is connected with each guide wheel (50) of the rolling guide wheel mechanism. The stop mechanism (Ⅲ) is integrated inside the guide wheel (50); when the elevator stalls, no matter whether it is ascending or descending, the stop mechanism (Ⅲ) can stop the rotation of the guide wheel (50), and cooperate with the hydraulic actuator to provide The pressing force makes the guide wheel (50) hug the guide rail (1) to realize emergency braking.

Embodiment two:

Referring to Figures 1 to 8, this embodiment is basically the same as Embodiment 1, and the special features are as follows:

The elevator rolling guide shoe with braking function is characterized in that: the rolling guide wheel mechanism (I) includes a brake drum (3), wear-resistant rubber (4), guide shoe base (7), main Swing rod (6), secondary swing rod (8), limit spring (10), first connecting long rod (20), wherein the outer layer of brake drum (3) is inlaid with a layer of wear-resistant rubber (4) to form Guide wheel (50), main and minor fork (6,8) lower ends are all hinged with guide shoe base (7), two fork ( A rotating shaft (16) is installed between 6 and 8), the brake drum (3) is installed on the rotating shaft (16), and the first connecting rod (20) passes through the main swing rod on the side of the guide wheel (50) (6) After connecting with the fixed vertical column of the guide shoe base (7), the limit spring (10) is installed on the outer end of the first connecting rod (20).

The elevator rolling guide shoe with braking function is characterized in that: the hydraulic actuator (II) includes a driving hydraulic cylinder (5), a driving hydraulic cylinder mounting plate (13), a second and a third connecting rod (18, 19), wherein the second and third connecting rods (18, 19) pass through the main swing rod (6) and are connected to the fixed vertical column of the guide shoe base (7), driving the hydraulic cylinder mounting plate ( 13) It is fixed on the second and third connecting rods (18, 19) by bolts, the driving hydraulic cylinder (5) is fixed on the mounting plate (13) of the driving hydraulic cylinder, and the outer end of the piston rod of the driving hydraulic cylinder (5) Hinged with main pendulum (6).

The elevator rolling guide shoe with braking function is characterized in that: the stop mechanism (Ⅲ) includes a brake base plate (9), a brake pad (22), a brake shoe (23), a support pin (32), and the hydraulic cylinder (40), wherein the brake drum (3) is fastened with the brake bottom plate (9), and a brake shoe (23) is arranged on the left and right sides of the brake bottom plate (9), and each Parallel to the brake base plate (9), the upper ends of the two brake shoes (23) are hinged to the brake base plate (9) through the support pins (32), so that the brake shoes (23) can be wound around and fixed on the brake base plate (9) The lower support pin (32) swings, the brake pad (22) is fixed on the brake shoe (23), the hydraulic cylinder (40) is on the upper part of the brake bottom plate (9), and the two brake shoes (23) Upper end points conflict; Up and down return springs (24, 31) and brake shoe clearance adjustment springs (27) are housed between the two brake shoes (23).

Embodiment three:

The specific structure of this embodiment is described in detail as follows:

What Fig. 2 shows is the three-dimensional structural view of the forward guide wheel of the elevator guide shoe, and the two lateral guide wheels have the same working structure. The general structure of the rolling guide wheel mechanism (I) in the present invention will be described below with reference to FIG. 2 .

The rolling guide wheel mechanism includes brake drum (3), wear-resistant rubber layer (4), guide shoe base (7), primary and secondary swing bars (6, 8), limit spring (10), connecting rod (20 ). Among them, the guide shoe base (7) is fixed to the elevator car, the brake drum (3) rotates around the guide wheel rotation axis (16), and can swing around the swing lever rotation axis (17) along with the main swing lever (6). The brake drum (3) is covered with wear-resistant rubber (4) and is in contact with the front of the T-shaped guide rail (1). The first connecting long rod (20) passes through the main swing rod (6) and the The columns are connected, the pressure spring (10) passes through the second connecting rod (20) and applies a preload to the main swing rod (6) under the action of the limit bolt (11), and the guide shoe dust cover (2) Be installed on the top of three guide wheels (50).

The general working principle of the rolling guide wheel mechanism (I) in the present invention will be described below with reference to FIG. 2 .

The rolling guide wheel mechanism (Ⅰ) is composed of a brake drum (3) and wear-resistant rubber (4). The rolling guide wheel rotates around the rotating shaft of the guiding wheel (16) and can rotate around the rotating shaft of the swinging rod with the main swinging rod (6). (17) Swing. When the elevator is running normally, the main swing rod (6) swings around the swing rod rotation axis (17) under the elastic support of the spring (10) to maintain the three working positions of the wear-resistant rubber (4) and the T-shaped guide rail (1). There is a good and stable contact on the surface, so that the three guide wheels (50) of the rolling guide wheel mechanism (I) are close to the three working surfaces of the T-shaped guide rail (1), so as to limit the movement of the elevator car in the horizontal direction , can realize the function of reducing the vibration and noise in the elevator running and improving the comfort of the ride that the general rolling guide shoe has.

In addition, the pressure spring (10) also provides a function of limiting the position of the guide wheel (50), preventing the guide wheel from deviating from the guide rail (1) under accidental conditions.

Referring to Fig. 2, the general structure of the hydraulic actuator (II) in the present invention will be described.

The hydraulic actuator (II) includes the driving hydraulic cylinder (5) and its mounting plate (13), the main swing rod (6), the second and third connecting long rods (18, 19). Among them, the second and third connecting long rods (18, 19) pass through the main swing rod (6) and are connected with the vertical column on the guide shoe base (7), and drive the hydraulic cylinder mounting plate (13) on the limit bolt ( 12) is fixed on the second and third connecting rods (18, 19), the drive hydraulic cylinder (5) is installed on the drive hydraulic cylinder mounting plate (13), and the push rod head of the drive hydraulic cylinder (5) A hinged device (14) is installed at the top, and the driving hydraulic cylinder (5) is hinged with the main swing rod (6) through connecting bolts (15).

The general working principle of the hydraulic actuator (II) in the present invention will be described below with reference to FIG. 2 .

When the elevator stalls, the driving hydraulic cylinder (5) fixed on the second and third connecting rods (18, 19) drives the main swing rod (6) to swing around the swing rod rotation axis (17), and then drives the The guide wheel (50) of the rolling guide wheel mechanism (I) formed by the brake drum (3) and wear-resistant rubber (4) is pressed to the three working surfaces of the T-shaped guide rail (1) and hugged therewith.

Referring to the exploded view of the guide wheel (50) shown in Figures 3 and 4, the specific composition diagram of the stop mechanism (Ⅲ) shown in Figures 5 and 6, and the guide wheel (50) and support shown in Figures 7 and 8 The assembly diagram of the fork (6,8) of the guide wheel (50) illustrates the composition and working principle of the stop mechanism (Ⅲ).

The stop mechanism (Ⅲ) includes a brake base plate (9), a brake pad (22), a brake shoe (23), a support pin (32), and a hydraulic wheel cylinder (40). As shown in Figure 3, the brake drum (3) is removed, and the brake bottom plate (9) and the braking mechanism integrated on the brake bottom plate (9) appear. As shown in Figure 4, there is an inspection hole (21) on the brake drum (3) to facilitate inspection of the working conditions of the internal stop mechanism (Ⅲ) of the guide wheel (50). As shown in Fig. 5, it is a support for the brake base plate (9) and a series of brake shoes (23) installed thereon. As shown in Figure 6, the brake base plate (9) is removed to focus on the main components of the brake mechanism. Brake pads (22) and brake shoes (23) constitute a leading-shoe structure similar to automobile drum brakes; brake shoes (23) are supported by brake shoe supports (36,37) and The moving bottom plate (9) keeps a certain distance; the brake shoe (23) can rotate around the support pin (32) under the action of the support pin (32), support pin cover plate (33) and cotter pin (34); adjust The cam (38) rotates around itself under the action of the cam adjustment knob (41), thereby driving the brake shoe (23) to rotate around the support pin (32) to adjust the brake pad (22) and the brake drum (3) The gap between the brake shoe (23) is kept parallel to the brake bottom plate (9) under the action of the brake shoe limit spring (28), limit spring seat (29) and limit screw (30); The brake shoe (23) returns under the action of the upper and lower return springs (24, 31) and remains in rigid contact with the brake hydraulic cylinder (40); 42), it is fixed on the brake base plate (9); a slotted brake shoe spreader (25) is installed between the two brake shoes (23), and the gap between the spreader (25) and the brake shoe is adjusted The block (26) and the brake shoe clearance adjustment spring (27) work together to adjust the force distribution of the brake hydraulic cylinder (40) to the two brake shoes when the two brake shoes are opened and returned, so that the two brake shoes The moving shoe can work well; under the situation of elevator stall, the brake shoe (23) pushes the brake pad (22) to open under the action of the brake hydraulic cylinder (40), and the brake pad (22) ) contact the brake drum (3) and rub against each other to stop the guide pulley.

The assembling relationship of the guide shoes will be described below with reference to Fig. 1 , Fig. 7 and Fig. 8 .

The brake bottom plate (9) is fixed together with the secondary swing rod (8) under the action of the brake bottom plate connecting bolts (43); the brake bottom plate (9) and the secondary swing rod (8) are (16) is connected with the main swing rod (6); the main swing rod (6) and the secondary swing rod (8) are connected with the guide shoe base (7) through the swing rod rotation shaft (17).

The general working principle of the present invention for realizing emergency braking will be described below with reference to FIG. 2 .

In the case of elevator stall, the brake pads (22) contact with the brake drum 3) and rub against each other to brake the guide wheel, and then drive the hydraulic cylinder (5) to drive the main swing rod (6) around the swing rod rotation axis ( 17) Swing, and then drive the guide wheel (50) of the rolling guide wheel mechanism (I) composed of the brake drum (3) and wear-resistant rubber (4) to press against the three working surfaces of the T-shaped guide rail (1) and The friction can realize emergency braking.

According to this embodiment, when the elevator is running normally, the three guide wheels (50) of the rolling guide wheel mechanism (I) are closely attached to the three working surfaces of the T-shaped guide rail, which can limit the movement of the elevator car in the horizontal direction. It can reduce the vibration and noise during the operation of the elevator and improve the comfort of the ride; when the elevator stalls, the stop mechanism (Ⅲ) and the hydraulic actuator (Ⅱ) work together to provide enough force for the guide wheel ( 50) Stop and rub against the elevator guide rail (1), so it can generate enough frictional force, so it can actually make the elevator car emergency brake.

Therefore, the present invention allows the guide shoe to realize the dual functions of guiding and emergency braking, and the function of the guide shoe can be changed in time according to the needs of the elevator operation without mutual interference.

Claims (1)

1. An elevator rolling guide shoe with a braking function, comprising: a rolling guide wheel mechanism (I), a hydraulic actuator (II) and a stop mechanism (III), characterized in that: the rolling guide wheel mechanism (I The three guide wheels (50) of the guide rail (1) are closely attached to the three working surfaces of the guide rail (1), the hydraulic actuator is connected with each guide wheel (50) of the rolling guide wheel mechanism, and the stop mechanism ( Ⅲ) Integrated inside the guide wheel (50); when the elevator stalls, whether it is ascending or descending, the stop mechanism (Ⅲ) can stop the guide wheel (50) from rotating, and cooperate with the pressing force provided by the hydraulic actuator , so that the guide wheel (50) hugs the guide rail (1) to realize an emergency stop; the rolling guide wheel mechanism (I) includes a brake drum (3), wear-resistant rubber (4), guide shoe base (7), The main swing rod (6), the secondary swing rod (8), the limit spring (10), the first connecting long rod (20), wherein the outer layer of the brake drum (3) is inlaid with a layer of wear-resistant rubber (4) The guide wheels (50) are formed, the lower ends of the primary and secondary swing bars (6, 8) are hinged with the guide shoe base (7), and the two swing bars on both sides of each guide wheel (50) in the three guide wheels (50) A rotating shaft (16) is housed between (6, 8), the brake drum (3) is installed on the rotating shaft (16), and the first connecting rod (20) passes through the main pendulum on one side of the guide wheel (50). The rod (6) is connected to the fixed vertical column of the guide shoe base (7), and the limit spring (10) is installed on the outer end of the first connecting long rod (20); the hydraulic actuator (II) includes a drive Hydraulic cylinder (5), driving hydraulic cylinder mounting plate (13), second and third connecting rods (18, 19), wherein the second and third connecting rods (18, 19) pass through the main swing rod (6) Connected with the fixed vertical column of the guide shoe base (7), the driving hydraulic cylinder mounting plate (13) is fixed on the second and third connecting rods (18, 19) by bolts, and the driving hydraulic cylinder (5) Fixed on the mounting plate (13) of the driving hydraulic cylinder, the outer end of the piston rod of the driving hydraulic cylinder (5) is hinged to the main swing rod (6); the stop mechanism (Ⅲ) includes the brake base plate (9), brake Brake pads (22), brake shoes (23), support pins (32), and hydraulic cylinders (40), wherein the brake drum (3) is fastened with the brake bottom plate (9), and the brake bottom plate (9 ) and one brake shoe (23) is arranged on the left and right, and both of them are parallel to the brake bottom plate (9). The movable shoe (23) can swing around the support pin (32) fixed on the lower part of the brake base plate (9), the brake pad (22) is fixed on the brake shoe (23), and the hydraulic cylinder (40) is in the braking position. Base plate (9) top, conflicts with the upper end point of two brake shoes (23); Up and down return spring (24,31) and brake shoe clearance adjustment spring (27) are housed between two brake shoes (23).