330 results about "Hydraulic brake" patented technology

The application discloses an intelligent electric chassis configuration and a fault-tolerant control method of the intelligent electric chassis, and relates to the technical field of electric chassis. The chassis configuration comprises a front axle centralized motor drive assembly, a rear axle distributed motor drive assembly, a front axle electronic hydraulic brake system, a rear axle electronic mechanical brake system and a chassis domain controller. The front axle centralized motor drive assembly comprises a centralized drive motor, a front wheel speed reducer and a drive half shaft which are sequentially connected. The rear axle distributed motor drive assembly comprises a left rear wheel end drive motor and a left rear wheel speed reducer which are sequentially connected, and a right rear wheel end drive motor and a right rear wheel speed reducer which are sequentially connected. The front axle electronic hydraulic brake system comprises a first main brake unit and a redundant brake unit. The rear axle electronic mechanical brake system comprises a second main brake unit. The chassis domain controller is used for controlling the centralized drive motor, the left and right rear wheel end drive motors, the first main brake unit, the redundant brake unit, the second main brake unit, a front axle steer-by-wire system, an intelligent suspension system and an intelligent tire. The application can improve the chassis safety and fault-tolerant capability to support high-level automatic driving functions.

The invention discloses a braking energy distribution method and system based on braking noise prediction and electronic equipment. The method comprises the steps that braking noise time sequence data, vehicle speed time sequence data, hydraulic braking torque time sequence data and pedal travel time sequence data of a current vehicle are obtained; inputting the braking noise time sequence data, the hydraulic braking torque time sequence data and the pedal travel time sequence data into a pre-trained braking noise prediction model to obtain a braking noise prediction value of the current vehicle after a preset time step; determining a corresponding braking noise threshold value according to the current working condition and the current driving mode of the current vehicle; and when the braking noise prediction value is larger than the braking noise threshold value, the braking energy distribution proportion is adjusted, so that the energy recovery torque is increased, and the hydraulic braking torque is reduced. According to the method, the braking noise of the vehicle is maintained below the threshold value through dynamic distribution of the braking energy, interference to users in the vehicle is avoided, the driving comfort of the vehicle is improved, and the method can be applied to the technical field of vehicle control.

An oil pressure brake with a double-sealing structure comprises a brake pump body, a brake handle and an oil pipe assembly. The brake pump body is provided with a pressure cylinder and an oil storage cylinder, a piston push rod assembly acted by the brake handle is arranged in the pressure cylinder, and the pressure cylinder is communicated with the oil storage cylinder through an oil pressure adjusting hole. The piston push rod assembly comprises a front piston rod and a rear piston rod, a pushing cavity is formed in the rear piston rod, and the front piston rod can enter the pushing cavity; the front piston rod is provided with an oil guide cavity and an oil overflow hole; the front piston rod is further sleeved with a one-way piston oil seal, the one-way piston oil seal abuts against the inner wall of the pressure cylinder, and the one-way piston oil seal is located on the front side of the oil overflow hole. The hydraulic brake has the advantages that a new oil way is formed through the oil guide cavity and the oil overflow hole formed in the front piston rod, so that only one oil pressure adjusting hole is reserved between the pressure cylinder and the oil storage cylinder, only one one-way piston oil seal is used on the piston push rod assembly, and the brake use function can be achieved.

This invention relates to the field of vehicle technology, specifically providing a control method for a vehicle EPB system, aiming to solve the problem that existing vehicles struggle to brake according to different deceleration requirements when malfunctions or hydraulic braking modules fail. To this end, the vehicle EPB system of this invention includes a braking mechanism configured to clamp and release the vehicle's wheels; the control method includes: acquiring the vehicle's deceleration request; determining a target clamping force based on the acquired deceleration request; and controlling the braking mechanism to incrementally increase the clamping force until the clamping force reaches the target clamping force. The control method of this invention can brake the vehicle regardless of whether a malfunction occurs or the hydraulic braking module fails, with good braking effect, thus improving vehicle safety.

The invention discloses a parking braking mechanism of an electronic mechanical braking system. The parking braking mechanism comprises a valve block (1), a flange plate (2), a speed reducing mechanism module (3), a hydraulic cylinder body module (4), a simulator cylinder body (5), an ECU controller (6), a driving motor module (7) and a liquid storage tank (8). According to the parking braking mechanism of the electronic mechanical braking system, modular design is adopted, the machining difficulty of a single assembly is greatly reduced, the process assemblability is optimized, the assembly flexibility of a production line is improved, and the assembly process is simpler and more reliable.

Method for estimating the coefficient of friction of a hydraulic brake system with axle-specific pressure build-up of a motor vehicle, comprising the steps: a) Adjusting a braking torque on a wheel of a first axle or on a first axle of the motor vehicle via an actuator system which has a higher positioning accuracy than the hydraulic braking system; b) Measurement of the deceleration of the wheel or axle or motor vehicle caused by the braking torque; c) Determination of the transmission behavior between braking torque and deceleration of the wheel or axle or motor vehicle; d) Applying a target braking torque to the wheel or axle of the motor vehicle via the hydraulic braking system; e) Measurement of the deceleration of the wheel or axle or motor vehicle caused by the braking torque; f) Estimating the actual braking torque via the inverse of the transmission behavior between braking torque and deceleration of the wheel or axle or motor vehicle determined in step c); (g) Calculation of the coefficient of friction of the hydraulic brake system with axle-specific pressure build-up for the first axle of the motor vehicle, wherein the method also includes the determination of the coefficient of friction of the hydraulic brake system with axle-specific pressure build-up for at least one further axle of the motor vehicle.

Brake caliper (1) for a hydraulic disc brake, designed to enable the production of both radially and axially mounted hydraulic disc brakes for passenger cars, commercial vehicles and armored vehicles using a general forming pattern and general machining equipment, comprising the following: - an inner brake caliper half (1.1) configured to allow both radial and axial connection by machining hydraulic brake discs (1) with a radial connection; - Connection points ( 1.1.1) having an elliptical shape, which enables the machining of the inner brake caliper half (1.1) for both a radial and an axial connection from the same forming part; - rear extensions of connecting elements (1.1.6) that extend from the connecting elements (1.1.1) and structurally connect the inner brake caliper half (1.1) to the piston housings (1.1.2) and the connecting bolt extensions (1.1.3) through the forming surfaces.

The utility model discloses a floating type hydraulic brake, which relates to the field of hydraulic brakes and comprises a main mounting plate, the top surface of the main mounting plate is vertically, downwards and symmetrically welded with supporting vertical rods, the top ends of the supporting vertical rods are horizontally and fixedly welded with an auxiliary top plate, and the top surfaces of the main mounting plate and the auxiliary top plate are symmetrically provided with mounting through holes. Fixed top blocks are symmetrically welded to the top face of the main mounting plate, an overturning arc rod is vertically arranged on the side edge between the fixed top blocks, a fixed paired block is in butt joint with the inner side edge of the overturning arc rod, a brake pad is fixedly arranged on one side edge of the fixed paired block, and a limiting top rod is fixedly connected to the top end of the overturning arc rod. Auxiliary side rods are horizontally and symmetrically arranged on the two side edges of the overturning arc rod, multiple limiting and guiding structures are adopted, so that the situation of deflection and dislocation is not likely to be formed when the overturning arc rod is used for braking, and the situation of shaking is avoided when the overturning arc rod is installed and used for braking through the fixing and limiting structures on the upper face and the lower face.

Brake lever arrangement for a hydraulic brake device (1) with a brake lever (2) for actuating a hydraulic piston (20), with a pivot axis (4) via which the brake lever (2) can be pivotably attached to a housing (6), with an actuator (10) which can be pivotably attached to the housing (6) about the pivot axis (4), wherein the actuator (10) is designed and arranged such that the piston (20) can be actuated by the brake lever (2) via this actuator, and can be supported on the housing (6) or on the piston (20) by a torsion spring (16) which is mounted on the pivot axis (4) and acts on the brake lever (2) with a spring force in the direction of actuation.

The application relates to a ship auxiliary berthing method and system based on video monitoring and a terminal, and relates to the field of ship berthing technology. The application comprises the following steps: acquiring initial ship berthing information of a ship; controlling a tugboat to assist the ship to berth according to the initial ship berthing information; acquiring real-time ship berthing speed information; judging whether the real-time ship berthing speed information exceeds a corresponding berthing speed of preset reference berthing speed information; if the real-time ship berthing speed information does not exceed the reference berthing speed information, continuously acquiring the real-time ship berthing speed information; and if the real-time ship berthing speed information exceeds the reference berthing speed information, outputting brake information and starting a preset hydraulic brake device to brake the ship according to the brake information. The application has the effect of reducing the risk of ship collision with a wharf.

Hydraulic unit of an electronically controlled brake system, comprising a modulator block (80) with several receiving bores (164, 181 to 185) in which several valves (64, 81 to 84) and pressure sensors (85a, 85b) coupled to a master cylinder (20) are installed to control hydraulic brake pressure supplied to vehicle wheels, wherein passages (180) connecting the receiving bores are formed in the modulator block (80) and the passages (180) are formed such that they are divided into two layers (P1, P2), wherein the receiving bores (164, 181 to 185), in which an inlet valve (81), an outlet valve (82), a start valve (83), a simulation valve (64), a pressure sensor (85a, 85b) and a switching valve (84) are installed, are formed in one surface of the modulator block (80) and the receiving bore (186), in which a shut-off valve (86) is installed, is formed in the other surface of the modulator block (80), wherein the multiple receiving bores (164, 181 to 185) formed in a surface of the modulator block (80) have installed the inlet valve (81), the outlet valve (82), the start valve (83), the simulation valve (64), the pressure sensors (85a, 85b) and the switching valve (84) in this order.

The present application relates to hydraulic valve, disclose a kind of liquid-filled valve, including energy accumulator (1) and the working oil path connected with inlet (P) and working oil port (A), the working oil path is provided with check valve (2), the energy accumulator (1) is connected with the reverse oil port of check valve (2), further comprising hydraulic control reversing valve (3) and hydraulic bridge path, the hydraulic control reversing valve (3) includes the first oil port (B1) connected with the inlet (P), the second oil port (B2) connected with return oil port (T) and the third oil port (B3) connected with the hydraulic bridge path, the energy accumulator (1) and the hydraulic bridge path are respectively connected with the hydraulic control port of the hydraulic control reversing valve (3), to control the switching of the hydraulic control reversing valve (3).The present application also discloses a kind of running hydraulic brake system and running hydraulic steering system.The liquid-filled valve of the present application increases the width of energy accumulator working pressure interval, with wide-range pressure maintaining function.

A drawworks brake performance assessment system (115, 215, 315) comprising a drawworks (116, 216, 316) comprising a rotatable spool (220, 320); a braking system comprising a rotor (232, 332) associated with the rotatable spool and at least one hydraulic disc brake (234,334) comprising a master cylinder assembly (236, 336) and a caliper assembly comprising a caliper (242, 342) and opposing brake pads, wherein the master cylinder assembly is operable with the caliper assembly to manipulate one of the opposing brake pads to apply a clamping force to the rotor; and a brake sensor system (160, 260, 360) comprising a sensor (264, 364) and an operations module (272, 372), the sensor being operable to measure a displacement distance between one of the opposing brake pads and a surface of the rotor, and to output corresponding sensor data to the operations module that is operable to receive and process the sensor data and to determine one or more performance characteristics of the braking system based on the sensor data.

This application relates to a hydraulic brake cylinder pressure control system and its control method. The control system includes a pressure generation module and a pressure control module. The pressure generation module includes a check valve, an external accumulator, and an accumulator sensor. The check valve is connected to an oil tank. The pressure control module includes a proportional solenoid valve connected to the external accumulator and the brake cylinder; a pressure-holding solenoid valve located at the overflow port of the proportional solenoid valve, which is connected to the oil tank via the pressure-holding solenoid valve; a brake cylinder sensor collecting and outputting the brake cylinder pressure; and a brake cylinder pressure switch electrically connected to the brake cylinder sensor. During the relief condition, the proportional solenoid valve is de-energized and the pressure-holding solenoid valve is energized. During coasting or braking conditions, the proportional solenoid valve is energized, and the pressure-holding solenoid valve is de-energized after a delay. This application reduces the usage rate of the proportional solenoid valve and improves system reliability through the coordinated control of the proportional solenoid valve and the pressure-holding solenoid valve.

The utility model relates to the technical field of hydraulic brakes, and discloses a split type monorail crane speed reducer mounting seat which comprises a mounting seat body, a fixing disc is fixedly mounted on one side of the mounting seat body, clamping blocks are fixedly mounted on the two sides of the fixing disc, and an elastic clamping seat is correspondingly and fixedly mounted on one side of the fixing disc. A speed reducer body is arranged on one side of the mounting base body, a connecting disc is rotationally connected to the surface of the speed reducer body, the connecting disc makes contact with the fixing disc and is connected with the elastic clamping base in a clamped mode, concave plates are fixedly mounted on the two sides of the connecting disc and are in sliding connection with the clamping blocks, and two bolts are connected to one side of the connecting disc in a penetrating mode; the bolts are in threaded connection with the fixing disc, the pressing piece is correspondingly installed on one side of the connecting disc and makes contact with the elastic clamping base, pre-positioning of the speed reduction motor body can be achieved through the concave plate and the clamping block, the number of the bolts is reduced, a quick disassembling structure is adopted, the installation difficulty is reduced, and the installation efficiency and maintenance convenience of the monorail crane speed reducer body are improved.

The application discloses a mountain rail vehicle enhanced braking system and relates to the technical field of rail vehicle braking control. The system comprises the following steps: collecting a rail position vector and an arc length, calculating rail curvature and rail slope, combining a current vehicle speed with a target speed to solve a braking demand acceleration value, generating a slope parameter and a curve parameter; adjusting a wheel-rail hydraulic braking torque value according to a braking force distribution ratio, controlling a rack rail brake engagement depth and a vibration frequency through a rack rail action instruction, generating a wheel-rail system state report and a rack rail working log; extracting a slope parameter, an actual value of adhesion force and a rack rail engagement efficiency in a braking process from the wheel-rail system state report and the rack rail working log, and combining a terrain braking curve to perform closed-loop optimization. The application performs self-learning and self-adaptive adjustment on the braking process through closed-loop feedback and parameter optimization, so that the energy utilization efficiency and the service life of key components are improved while the braking efficiency is ensured.

The utility model relates to a kind of hydraulic braking system for engineering machinery, including hydraulic pump, brake liquid filling valve, front axle running brake, rear axle running brake, brake foot valve and hydraulic oil tank, brake liquid filling valve includes pressure oil port and first oil outlet;The input port of hydraulic pump is fluidly connected with the hydraulic oil tank, and the output port of hydraulic pump is fluidly connected with the pressure oil port of brake liquid filling valve;First oil outlet is fluidly connected with front axle running brake and rear axle running brake respectively via brake foot valve;Hydraulic braking system further includes energy accumulator and brake direction control valve, energy accumulator is fluidly connected with first oil outlet, brake direction control valve is arranged between brake liquid filling valve and brake foot valve and has first position, when being in first position, hydraulic fluid from energy accumulator and first oil outlet can be supplied to front axle running brake and rear axle running brake via brake direction control valve and brake foot valve.The utility model further relates to a kind of engineering machinery.

The invention provides a load self-adaptive constant tension winch control system, which comprises a PLC (Programmable Logic Controller), a hydraulic motor, a hydraulic winch, a winch steel wire rope, a fixed pulley, a working boat, a rotary encoder, a shaft pin type sensor and a constant tension loop consisting of three loops, and is characterized in that the first loop comprises a preset oil tank, a main control valve and the hydraulic motor; the second loop comprises a preset oil tank, a main control valve, a shuttle valve, a pressure reducing valve, a hydraulic control reversing valve and a hydraulic brake; the third loop comprises a shuttle valve, an electromagnetic switch valve, a hydraulic control switch valve, an electric proportional overflow valve and a hydraulic motor, the system controls the electromagnetic switch valve and the electric proportional overflow valve at the same time through the PLC according to detection data of the rotary encoder and the shaft pin type sensor, accurate control over the tension of the winch steel wire rope is achieved, and when waves rise, the winch steel wire rope is driven to rotate. The system controls the hydraulic winch to actively lift; and when the waves descend, the system controls the hydraulic winch to descend passively, so that the tension of the winch wire rope is always kept within a preset range, and stable operation of the working boat is ensured.

To reduce power consumption when a vehicle is stopped. [Solution] A brake control device 80 is applied to a vehicle 10 equipped with a hydraulic braking device 50 and an electric parking device 60. A processing circuit 81 of the brake control device 80 includes a stop control unit 113 that activates the hydraulic braking device 50 so that the vehicle 10 is stopped by applying hydraulic braking force, a hold control unit 115 that executes stop hold control, including activating the electric parking device 60 so that the parking braking force increases toward a holding braking force that is greater than the hydraulic braking force at the time the vehicle 10 is stopped, and activating the hydraulic braking device 50 so that the hydraulic braking force decreases to 0 (zero), and a setting unit 117 that sets at least one of the increase rate of the parking braking force and the holding braking force when the stop hold control is being executed, based on the required braking force.

The application discloses an electro-hydraulic brake system for controlling vehicle wheel group braking, comprising a parking brake system and a service brake system, and specifically comprising an oil tank, a motor pump group, a two-position two-way electromagnetic reversing valve, a pump outlet pressure gauge, an accumulator liquid charging valve, a two-position three-way electromagnetic reversing valve, a parking brake accumulator, a parking brake pressure gauge, a pressure reducing valve, a service brake accumulator, a pressure sensor, a service brake proportional valve, a motor parking brake, a speed reducer service brake, a vehicle wheel group, a wheel group driving motor, a hydraulic pipeline and an electrical control module. The parking brake system and the service brake system of the electro-hydraulic brake can independently or cooperatively operate, can control the brakes of four wheel groups of the vehicle in real time, can ensure the absolute stop of each wheel group of the vehicle, can maintain the parking of the vehicle under any working conditions such as slopes, can avoid the vehicle from tilting, vibrating and slipping when running due to road conditions, can meet the demand of efficient braking of heavy vehicles, and can improve the safety of the vehicle.

The invention provides a commercial vehicle disc brake electric control mechanical brake air chamber which comprises an air chamber side wall, an air chamber body is formed in the air chamber side wall, and a lead screw nut is rotationally arranged in the air chamber body; the driving motor is arranged at one end of the side wall of the air chamber, and an output shaft of the driving motor and the lead screw nut are coaxially arranged and are in driving connection; the electromagnetic clutch is arranged between the side wall of the air chamber and the output shaft and is used for locking or separating the output shaft and the side wall of the air chamber; a lead screw is in threaded connection with the interior of the lead screw nut, the lead screw is in non-rotating fit with the side wall of the air chamber, an avoiding cavity used for avoiding the lead screw is formed in the output shaft, braking is carried out in an electronic control mode, the effects that the braking response speed is high, and braking force is more accurate are achieved, and the braking efficiency is improved. And the integrated control with a whole vehicle chassis system and a whole vehicle controller is easier, and the volume of the whole device can be reduced by arranging the avoiding strong cavity for avoiding the lead screw on the output shaft.

1. Name of the product in this design: Electric bicycle hydraulic brake (XD-L4). 2. Application of this design: This design is used for bicycle hydraulic brakes. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: 3D view 1.

The utility model relates to power device technical field, concretely is a kind of multifunctional hydraulic cycloid motor, its compact structure, small space occupation, low use cost, it includes motor body, hydraulic brake and hydraulic valve group, its characterized in that, the motor body with the hydraulic brake is integrated structure, the output shaft of the motor body passes through the hydraulic brake and end portion is equipped with output gear, hydraulic valve group is fixed on the motor body, the oil port on the motor body is directly with the oil port of hydraulic valve group butt joint, the hydraulic valve group is also connected the hydraulic brake by oil pipe, two working oil ports are set up on the hydraulic valve group.

The utility model relates to the technical field of train hydraulic brake clamps, and discloses an intercity train hydraulic brake clamp with a multi-sealing structure, which comprises a mounting seat, the left side of the mounting seat is fixedly connected with a hydraulic rod body, and an inner cavity of the hydraulic rod body is movably connected with a piston rod. A second placing cavity is formed in the top of the left side of the inner surface of the mounting seat. According to the inter-city train hydraulic braking clamp with the multi-sealing structure, a reset spring recovers deformation when losing the influence of force, extends upwards and drives a movable rod to move upwards, the movable rod drives a first pressing rod to move upwards to press a first sealing gasket, meanwhile, a threaded rod drives a threaded sleeve to move downwards under the action of threads in the rotating process, and the first sealing gasket is tightly pressed; the thread sleeve drives the second pressing rod to move downwards through the connecting plate to press the second sealing gasket, the first sealing gasket and the second sealing gasket are positioned through the different limiting assemblies on the two sides, loosening is avoided, and the overall sealing effect is effectively improved.

The application discloses an intelligent driving throttle override control method, a control system, a vehicle and a storage medium. The control method comprises the following steps: issuing a throttle override signal; issuing a deceleration request; issuing a negative torque capability signal; performing electro-hydraulic brake distribution and controlling the vehicle to execute braking; wherein the deceleration request exit curve and the negative torque capability exit curve are both S-shaped curves. The intelligent driving control system comprises: a hybrid power controller; an intelligent driving controller; a brake distributor. The vehicle comprises: a memory; a processor; a runnable program, the runnable program being stored in the memory, and the runnable program being executed by the processor to implement an intelligent driving throttle override control method according to any one of the above. The storage medium stores computer executable instructions, and the computer executable instructions are used for making a computer execute an intelligent driving throttle override control method. The exit strategy of the scheme simulates human driving characteristics and optimizes driving smoothness.

The present application relates to the field of new energy vehicle control, in particular to a new energy vehicle electronic hydraulic brake system failure processing system and method, real-time monitoring of the state signal and fault message of the electronic hydraulic brake system EHB; hierarchical response according to the monitored fault type; when it is determined that the electronic hydraulic brake system EHB has the highest level fault of losing basic braking capability, the first degradation strategy is triggered, when it is detected that the electronic hydraulic brake system EHB communication is completely lost but the highest level fault is not reported in advance, the second degradation strategy is triggered, solving the problem of how to ensure that the vehicle can still maintain the basic braking capability and safely limp when the electronic hydraulic brake system EHB of the new energy vehicle at the present stage has a serious fault leading to the failure of its hydraulic backup function, so as to avoid the complete paralysis of the vehicle and secondary safety accidents.

A braking system (1) for a motor vehicle, comprising a hydraulically actuated wheel brake (8-11) for each of several wheels of the motor vehicle, wherein each of the wheel brakes (8-11) is assigned a hydraulic brake actuator (12-15) for its actuation, which includes a hydraulic pump (P) and a drive motor (M) for the hydraulic pump (P). The braking system (1) is provided to include a master brake cylinder (6) which is hydraulically connected to the wheel brakes (8-11) for their actuation, wherein a controllable first isolating valve (T8-T11) is interposed between the master brake cylinder (6) and each respective wheel brake (8-11).

The invention discloses an integrated braking system and a detection method. The integrated braking system comprises a liquid storage pot; the liquid storage pot is connected with the pedal simulation unit and the pressurizing unit, and the pedal simulation unit is connected with the braking unit through a first hydraulic loop and performs hydraulic braking control on the braking unit; the pressurizing unit is connected with the first hydraulic loop through a second hydraulic loop and is used for loop detection; the first hydraulic loop and the second hydraulic loop which are connected through the pedal simulation unit and the pressurization unit are used for detecting the hydraulic loop of the integrated braking system, whether the pressure buildup capacity, the air amount and the sealing performance of the integrated braking system meet preset threshold values or not is judged, a vehicle with problems can be detected in a whole vehicle manufacturing plant, and the integrated braking system can also be used for an after-sale maintenance end. And detecting the brake system after the brake system is maintained.

The utility model relates to the field of connectors, in particular to a hydraulic brake hose assembly which comprises a connecting pipe, one end of the connecting pipe is further provided with a first protruding part, and the first protruding part and the end of the connecting pipe are integrally formed. The section size of the first protruding part is smaller than that of the connecting pipe. A first connector; the two ends of the connecting pipe are connected with the first connector and the second connector respectively; and the quick release assembly is arranged on the first protruding part of the connecting pipe and is matched with the first connector. According to the utility model, the advantages of convenience in use, disassembly and assembly and high practicability can be realized by effectively utilizing the self structural configuration.

The utility model relates to hoisting equipment technical field provides the special explosion -proof hoisting machinery transport hoist and mount equipment of limited space, including hoist frame, set up the mobile seat of hoist frame crossbeam and set up the lifting trolley of mobile seat, lifting trolley includes base and brake wheel, be equipped with the slide block of slidable on base, the hydraulic brake cylinder is hinged to have on slide block, base still be equipped with the screw rod of by motor drive, screw rod is connected with slide block drive connection, to drive slide block and the hydraulic brake cylinder hinged to its on mobile, be used for compensating the wear clearance of brake shoe.