CN219345340U - Rear axle adopting mechanical disc brake and capable of guaranteeing constant brake clearance - Google Patents

Abstract

The utility model relates to the technical field of braking, and discloses a rear axle which adopts a mechanical disc brake and can ensure constant braking clearance, comprising a half axle and a braking device, wherein the braking device is fixedly arranged at the tail end of the half axle; the braking device comprises a driving turntable and a compensation piece, the compensation piece comprises a first supporting leg, a compensation groove is formed in the end face of the driving turntable, and the first supporting leg is positioned in the compensation groove; the width of the compensating groove is in the range of 0.5-5mm plus the diameter of the first leg. The problem that the existing rear axle is difficult to stably maintain a brake clearance is solved.

Description

Rear axle adopting mechanical disc brake and capable of guaranteeing constant brake clearance

Technical Field

The utility model relates to the technical field of braking, in particular to a rear axle which adopts a mechanical disc brake and can ensure constant braking clearance.

Background

Compared with a drum brake, the mechanical disc brake has various advantages, mainly comprising the following points: 1. the braking stability is strong, and the braking moment in the braking process is more gentle; 2. the heat fading resistance is good, the disc brake belongs to an external brake system, the heat dissipation is fast, and the influence of the change of the friction coefficient of the disc brake on the braking efficiency is small after the disc brake is heated for a long time; 3. the influence of contact water on the braking performance is small, the disc brake device is easy to throw away when being stained with water under the action of centrifugal force, and the friction plate can quickly restore to normal after the friction plate wipes the brake disc; 4. the friction plate is convenient to maintain, simple in structure, easy to replace and low in maintenance cost. As the hydraulic disc brake of contrast, there is the risk of oil leak after its oil pump live time has been long, and the brake of both sides can't work after the oil pump oil leak, and mechanical disc brake even if the brake of one side is broken, the other side still can work, and the safety in utilization is higher. At present, aiming at the defects of mechanical automatic compensators such as electric vehicles, motorcycles and the like in the market, the applicant applies for an automatic compensating mechanical brake device with the bulletin number of CN207830419U in the 12 th month and 27 th year of 2017. However, the application document does not describe how to stably maintain the braking gap, but only realizes automatic compensation follow-up, but continuous automatic compensation follow-up can reduce the original braking gap and further cause braking locking to bring harm to a user, if the mechanical disc brake can ensure a constant braking gap through automatic compensation, the using time of a rear axle provided with the mechanical disc brake can be greatly prolonged, but the prior automatic compensation rear axle is difficult to stably maintain the original braking gap and is easy to automatically compensate too much or too little, so the inventor proposes a rear axle adopting the mechanical disc brake and capable of ensuring the constant braking gap.

Disclosure of Invention

The utility model aims to provide a rear axle which adopts a mechanical disc brake and can ensure constant brake clearance so as to solve the problem that the prior rear axle is difficult to stably maintain the original brake clearance.

In order to achieve the above purpose, the utility model adopts the following technical scheme: a rear axle adopting a mechanical disc brake and capable of ensuring constant brake clearance comprises a half axle and a brake device, wherein the brake device is fixedly arranged at the tail end of the half axle; the braking device comprises a driving turntable and a compensation piece, the compensation piece comprises a first supporting leg, a compensation groove is formed in the end face of the driving turntable, and the first supporting leg is positioned in the compensation groove; the width of the compensating groove is in the range of 0.5-5mm plus the diameter of the first leg.

The beneficial effect of this scheme is:

1. the rear axle is capable of maintaining a constant original brake clearance, which should remain unchanged after prolonged use, with an original clearance (about 0.3-0.5 mm) between the second friction plate and the brake disc in the stationary state of the vehicle. According to the prior art, when the brake is applied, the rocker arm moves the driving turntable to rotate a certain angle, the rolling body rolls a certain distance in the driving extrusion groove and enables the driving turntable to axially move, because one end of the screw rod is propped against the driving turntable, the connecting rod can drive the piston to move forward, and finally the piston can push the second friction plate, and the first friction plate and the second friction plate clamp the brake disc, so that the brake is realized. In actual use, the first friction plate and the second friction plate are worn and thinned continuously along with use, so that the original gap is widened continuously, and the braking effect is deteriorated.

However, the original gap can be compensated and the constant original brake gap can not be maintained, the width of the compensation groove needs to be limited in a certain range, the compensation groove and the compensation piece can enable the rear axle to maintain the constant brake gap, if the width of the compensation groove is narrower, the first support leg can be driven to rotate for a certain angle when the driving turntable rotates each time even if the friction plate is not worn, the friction plate is compensated when the friction plate does not need to be compensated, and as a result, the second friction plate is clamped continuously, and finally, the brake is locked to bring running danger; if the width of the compensation groove is wider, even if the first friction plate is worn to a certain extent, the side wall of the compensation groove is difficult to contact with the first support leg, the first support leg is not driven to rotate, and the first support leg can not rotate until the first friction plate is worn seriously and the rotation angle of the driving turntable is very large, so that the compensation amount of the compensation groove is difficult to compensate the actual wear amount of the first friction plate. The inventors have found that the width of the compensating groove is set to the diameter of the first leg plus 0.5-5mm, since the angular extent of rotation of the driving turntable is substantially fixed.

2. The mechanical disc brake device is relatively simple in structure, small in size and convenient to replace and maintain; and the automatic compensation disc brake device is configured, so that the service life of the rear axle is prolonged, and the stability and safety of the rear axle are enhanced.

Preferably, as an improvement, the braking device further comprises a clamp body and a screw rod, the clamp body comprises an inner cavity, the screw rod is arranged in the inner cavity, the compensation piece is sleeved on the screw rod and in interference fit with the screw rod, the compensation piece is a first wrapping spring, the screw rod is further sleeved with an anti-rotation mechanism which enables the screw rod to rotate unidirectionally, the anti-rotation mechanism comprises a second wrapping spring and a fixing piece, the second wrapping spring is in interference fit with the screw rod, one end of the second wrapping spring is a second supporting leg, the fixing piece penetrates through the clamp body, one end of the fixing piece is provided with a limiting groove, and the second supporting leg is inserted into the limiting groove.

The beneficial effects are as follows: because screw rod and first tight spring interference fit of wrapping up in during the brake, initiative carousel rotates to the brake direction, and the compensating groove lateral wall promotes the first stabilizer blade of first tight spring and rotates, and first tight spring can not hug tightly the screw rod, but still has interference fit's frictional force probably to drive the screw rod and rotate, in order to avoid the screw rod forward to rotate, consequently set up the second and wrap up in the spring, in the spacing groove is inserted to the second stabilizer blade, the screw rod can be hugged closely to the second tight spring when the screw rod forward rotates, consequently the screw rod is fixed.

Preferably, as an improvement, the brake device is fixed on the rear axle through the fixing mechanism, the fixing mechanism comprises a fixing sleeve, an adapter plate and a U-shaped fixing plate, the fixing sleeve is sleeved on the axle housing and in interference fit with the axle housing, the fixing sleeve and the adapter plate are fixedly connected through bolts, the U-shaped fixing plate is connected with the adapter plate through bolts, the brake device is fixed on the U-shaped fixing plate, and two ends of the U-shaped fixing plate limit the brake device. The beneficial effects are as follows: can guarantee the holistic stability of fixed knot structure through setting up fixed cover, set up the both ends of U type fixed plate and carry out spacingly to arresting gear, place arresting gear in the U type fixed plate on the one hand and block the assembly degree of difficulty when can reducing the installation, on the other hand receives the restriction and can guarantee that arresting gear can not produce the displacement because of receiving vibrations when using.

Preferably, as an improvement, a stop groove is formed on the circumferential surface of the driving turntable, and a stop pin which limits the driving turntable to only rotate unidirectionally is arranged, and the stop pin is clamped into the stop groove through the clamp body.

The beneficial effects are as follows: the arrangement of the stop pin can enable the active turntable to rotate only in one direction, can prevent the brake from reversing under special conditions, avoid safety accidents such as braking locking caused by reverse braking, and improve the use safety.

Preferably, as an improvement, the end face of the driving turntable is provided with a plurality of driving extrusion grooves which are uniformly distributed in the circumferential direction, rolling bodies are arranged in the driving extrusion grooves, each driving extrusion groove comprises a ball groove and a guide groove, each guide groove comprises a first groove and a second groove, the angles between the first groove and the second groove and the end face of the driving turntable are respectively a first inclination angle and a second inclination angle, the angle range of the first inclination angle is 15-50 degrees, and the angle range of the second inclination angle is 5-40 degrees.

The beneficial effects are as follows: the brake device can be ensured to have good braking effect, the braking efficiency of the clamp body can be effectively improved, the use requirement of rapid braking of most electric vehicles, motorcycles and tricycles on the market can be met, and the working efficiency is stable. If the first inclination angle is too large, the force applied to the rocker arm needs to be multiplied, the rotating resistance of the rocker arm is increased, the braking process is not smooth, the braking effect is affected, and in addition, even if the rotating angle of the rocker arm is small, the common braking becomes sudden braking due to more forward travel of the screw rod, and a certain danger is caused, so that the angle of the first inclination angle needs to be limited in a reasonable range; in the later stage of braking, the braking speed has reduced most when the rolling element is located the second groove, and the user can judge to what degree rotates the rocking arm according to the service condition, is used for adjusting braking speed, and second inclination angle scope is less simultaneously, and the user's braking needs the power that uses also less, and the operation is laborsaving and possess good braking effect.

Drawings

FIG. 1 is a schematic structural diagram of embodiment 1 of the present utility model;

FIG. 2 is a three-dimensional view of example 1 of the present utility model;

FIG. 3 is a schematic structural view of a brake device according to embodiment 1 of the present utility model;

FIG. 4 is a schematic view showing the internal structure of a brake device according to embodiment 1 of the present utility model;

fig. 5 is an exploded view showing the internal structure of the brake device according to embodiment 1 of the present utility model;

FIG. 6 is a schematic diagram of an active turntable according to embodiment 1 of the present utility model;

FIG. 7 is an end view of the driving turntable of embodiment 1 of the present utility model;

FIG. 8 is a cross-sectional view of an active extrusion groove according to embodiment 1 of the present utility model;

fig. 9 is a schematic structural view of a brake device according to embodiment 2 of the present utility model.

Detailed Description

The following is a further detailed description of the embodiments:

reference numerals in the drawings of the specification include: the speed reducer 1, the first half shaft 2, the second half shaft 3, the bridge 4, the axle housing 5, the braking device 6, the clamp body 7, the rocker arm 8, the piston 9, the first friction plate 10, the second friction plate 11, the threaded section 12, the connecting rod section 13, the driving turntable 14, the connecting rod 15, the driving extrusion groove 16, the rolling body 17, the first wrapping spring 18, the first supporting leg 19, the compensating groove 20, the second wrapping spring 21, the second supporting leg 22, the fixing piece 23, the limiting groove 24, the strip-shaped groove 25, the driven extrusion plate 26, the driven extrusion groove 27, the second pin body 28, the reset piece 29, the fixing sleeve 30, the adapter plate 31, the U-shaped fixing plate 32, the reinforcing rib 33, the stop groove 34, the stop pin 35, the first groove 36, the second groove 37, the shock absorber seat 38, the lug 39 and the bending part 40.

Example 1

The embodiment 1 is basically shown in fig. 1-8, and as shown in fig. 1 and 2, a rear axle adopting mechanical disc brake and capable of ensuring constant brake clearance comprises a speed reducer 1 and a rear axle body, wherein the rear axle body comprises a first half axle 2, a second half axle 3, a bridge frame 4, an axle housing 5 and two brake devices 6, the first half axle 2 and the second half axle 3 are arranged at two ends of the speed reducer 1, the speed reducer 1 is fixedly arranged on the bridge frame 4 through bolts, the axle housing 5 is arranged at two ends of the bridge frame 4 and sleeved on the first half axle 2 and the second half axle 3, the tail ends of the first half axle 2 and the second half axle 3 are respectively provided with a fixing mechanism and a brake disc, and the brake devices 6 are arranged on the fixing mechanism through bolts; the shock absorber seat 38 and the lug 39 are welded on both sides of the axle housing 5.

As shown in fig. 2, the fixing mechanism comprises a fixing sleeve 30, an adapter plate 31 and a U-shaped fixing plate 32, the fixing sleeve 30 is sleeved on the axle housing 5 and in interference fit with the axle housing 5, the fixing sleeve 30 and the adapter plate 31 are fixedly connected through bolts, the U-shaped fixing plate 32 is connected with the adapter plate 31 through bolts, the braking device 6 is fixed on the U-shaped fixing plate 32, two ends of the U-shaped fixing plate 32 limit the braking device 6, the overall stability of the fixing structure can be guaranteed through the fixing sleeve 30, two ends of the U-shaped fixing plate 32 limit the braking device 6, on one hand, the braking device 6 is placed in the U-shaped fixing plate 32 and clamped, the assembly difficulty during installation can be reduced, and on the other hand, the braking device 6 is limited during use, the braking device 6 can not generate displacement due to vibration. The plurality of reinforcing ribs 33 are arranged at the joint of the bridge 4 and the axle housing 5, so that the stability of the connection of the bridge 4 and the axle housing 5 is improved, and the joint of the bridge 4 and the axle housing 5 is prevented from being broken or deflected.

As shown in fig. 3 and 4, the braking device 6 comprises a caliper body 7, a rocker arm 8 and a piston 9, a first friction plate 10 is installed at the jaw of the caliper body 7, a second friction plate 11 opposite to the first friction plate 10 is installed at the end part of the piston 9, the first friction plate 10 and the second friction plate 11 can clamp a braking flange, the braking device further comprises a screw, a compensation piece and a rotating piece, the screw comprises a thread section 12 and a connecting rod section 13, the thread section 12 is in threaded connection with the piston 9, the rotating piece comprises a driving turntable 14 and a connecting rod 15, the caliper body 7 comprises an inner cavity, the screw and the driving turntable 14 are located in the inner cavity, one end of the connecting rod section 13 abuts against the driving turntable 14, a plurality of driving extrusion grooves 16 (shown in fig. 5) which are uniformly distributed in the circumferential direction are arranged on the end face of the driving turntable 14, and rolling bodies 17 are all installed in the driving extrusion grooves 16, and the rolling bodies 17 in the embodiment are steel balls; the compensation piece is a first wrapping spring 18, the first wrapping spring 18 is sleeved on the connecting rod section 13 and is in interference fit with the connecting rod section, a first supporting leg 19 extends out of one end of the first wrapping spring 18, as shown in fig. 7, a compensation groove 20 is formed in the end face of the driving turntable 14, and the first supporting leg 19 is located in the compensation groove 20; the connecting rod 15 passes through the inner cavity and is connected with the rocker arm 8, and a reset piece 29 is sleeved on the connecting rod 15; the piston 9 is slidably connected with the inner cavity of the pliers body 7, and the width of the compensating groove 20 is set to be the diameter of the first supporting leg 19 plus 0.5-5mm, and in this embodiment, the width of the compensating groove 20 is set to be the diameter of the first supporting leg 19 plus 3mm.

As shown in fig. 5, the connecting rod section 13 is further sleeved with an anti-rotation mechanism for enabling the screw rod to rotate unidirectionally, the anti-rotation mechanism comprises a second tightening spring 21 and a fixing piece 23, the second tightening spring 21 is in interference fit with the connecting rod section 13, one end of the second tightening spring 21 is a second supporting leg 22, the fixing piece 23 penetrates through the clamp body 7, one end of the fixing piece 23 is provided with a limiting groove 24, the fixing piece 23 is in threaded connection with the clamp body 7, and the second supporting leg 22 is inserted into the limiting groove 24. As shown in fig. 6, a passive extrusion plate 26 opposite to the active turntable 14 is further disposed in the inner cavity, a passive extrusion groove 27 matched with the active extrusion groove 16 is disposed on the end surface of the passive extrusion plate 26, the passive extrusion groove 27 has the same structure as the active extrusion groove 16 but opposite arrangement direction, and the active extrusion groove 16 comprises a spherical groove and a guide groove. As shown in fig. 8, the guide groove comprises a first groove 36 and a second groove 37, the angles between the first groove 36 and the second groove 37 and the end surface of the driving turntable 14 are respectively a first inclination angle and a second inclination angle, the angle range of the first inclination angle is 15-50 degrees, and the angle range of the second inclination angle is 5-40 degrees; the angle of the first inclination angle is set in the range, so that the rapid braking in the early stage of braking can be realized and the safety is ensured, if the angle is set too large, the force applied to the rocker arm 8 needs to be multiplied, the rotating resistance of the rocker arm 8 is increased, the braking process is not smooth, the braking effect is affected, in addition, even if the rotating angle of the rocker arm 8 is smaller, the screw rod advancing process is more, the ordinary braking is changed into sudden braking, and a certain danger is caused; the braking speed has been reduced by a large part when the rolling bodies 17 are in the second groove 37, and the user can decide, depending on the use situation, to what extent to turn the rocker arm 8 for adjusting the braking speed.

As shown in fig. 4, the piston is provided with a bar-shaped groove 25, and a first pin body is inserted into the bar-shaped groove through the clamp body and is in threaded connection with the clamp body. As shown in fig. 6, two pin holes are formed on the surface of the passive extrusion plate, which is close to the rocker arm, two second pin bodies 28 are arranged and penetrate through the clamp bodies to be inserted into the pin holes, and the positions of the pin hole openings are positioned between two adjacent passive extrusion grooves, so that the passive extrusion plate is prevented from rotating during use, and the active extrusion grooves and the passive extrusion grooves are prevented from being misplaced, and therefore the second pin bodies 28 are arranged and inserted into the pin holes, and the rotating precision of the disc brake device can be ensured; the arrangement of one second pin 28 also makes it difficult to ensure that the passive extrusion plate cannot shift, so that the insertion of two second pins 28 can ensure the position accuracy of the passive extrusion plate, and can play a role in positioning and installing the passive extrusion plate, thereby improving the assembly efficiency and accuracy.

As shown in fig. 6, a stop groove 34 is formed on the circumferential surface of the driving turntable 14, and a stop pin 35 which limits the driving turntable 14 to rotate only in one direction is arranged, the stop pin 35 passes through the clamp body 7 and is clamped into the stop groove 34, when the driving turntable 14 rotates in the forward direction within a certain range, the stop pin 35 does not influence the rotation of the driving turntable 14, and when the driving turntable 14 rotates in the reverse direction, the stop pin 35 can be blocked in front of a blocking surface of the stop groove 34 to prevent the rotation of the driving turntable 14, so that the driving turntable has a simple structure and good use effect; the stop groove 34 is L-shaped in cross section, so that the stop pin 35 can be ensured not to affect the forward rotation of the driving turntable 14 as much as possible, and the stop pin 35 can not interfere with the driving turntable 14 when the driving turntable 14 rotates forward to a certain range.

The specific implementation process is as follows:

the constant braking gap can be maintained, in this embodiment, a compensating groove 20 is formed in the end face of the driving turntable 14, a first tightening spring 18 is sleeved on the connecting rod section 13, one end of the tightening spring extends out to form a first supporting leg 19, the compensating groove 20 is formed in the end face of the driving turntable 14, and the first supporting leg 19 is located in the compensating groove 20. When the brake pad is not worn, compensation of gaps is not needed, and when the brake pad is braked, the driving turntable 14 is driven by the rocker arm 8 to rotate forward for alpha degrees, the first support leg 19 slides in the compensation groove 20 when the driving turntable 14 rotates forward, and the position of the first support leg 19 is not changed; when the brake pad is worn, the piston 9 needs to advance for a certain distance to compensate, when the brake is finished, the driving turntable 14 rotates forward by an angle of alpha+delta alpha under the drive of the rocker arm 8, at this time, the first supporting leg 19 contacts with the side wall of the compensation groove 20, the side wall of the compensation groove 20 pushes the first supporting leg 19 to rotate forward by an angle of delta alpha, the first tightening spring 18 rotates forward and cannot tightly clamp the connecting rod section 13, but still friction force of interference fit can drive the connecting rod section 13 to rotate, the second tightening spring 21 tightly clamps the connecting rod section 13 to keep the connecting rod section 13 still, the first supporting leg 19 rotates to drive the first tightening spring 18 to slide forward by an angle of delta alpha relative to the connecting rod section 13, after the brake is finished, the reset piece 29 enables the driving turntable 14 to rotate back to the original position, the driving turntable 14 rotates reversely by an angle of alpha+delta alpha, the side wall of the compensation groove 20 drives the first supporting leg 19 to return to the original position, the first supporting leg 19 rotates reversely by an angle of delta alpha, the first tightening spring 18 rotates reversely to tightly clamp the connecting rod section 13, the first tightening spring 18 drives the screw rod to rotate by an angle of delta alpha relative to the piston 9, and the piston 9 is connected with the inner cavity 7 of the pliers 7 and the piston 9 in a sliding mode to the piston 9, and the distance of the piston is further slid forward to the piston 11 is realized. The width of the compensation groove 20 should be limited in a certain range, if the width of the compensation groove 20 is too narrow, even if the friction plate is not worn, the first support leg 19 is driven to rotate by a certain angle every time the driving turntable 14 rotates, so that the friction plate is compensated when the compensation is not needed, and as a result, the second friction plate 11 is continuously clamped, and finally, the running danger is caused by braking locking; if the width of the compensating groove 20 is too wide, even if the first friction plate 10 is worn to some extent, the side wall of the compensating groove 20 is difficult to contact with the first leg 19, and the first leg 19 is not driven to rotate until the first friction plate 10 is worn more seriously and the rotation angle of the driving turntable 14 is very large, and as a result, the first leg 19 is not rotated, and as a result, the compensation amount thereof is difficult to compensate the actual wear amount of the first friction plate 10. The embodiment provides a rear axle body which adopts a mechanical disc brake and can ensure a constant brake clearance, the structure is relatively simple, the volume is small, and the mechanical disc brake device is convenient to replace and maintain; and the automatic compensation disc brake device is configured, so that a brake gap can be kept, the stability and safety of the vehicle are enhanced, and the service life of the rear axle body is prolonged.

Example 2

The embodiment is basically shown in fig. 9, the restoring member 29 shown in fig. 9 is a compression spring, two ends of the compression spring are provided with bending portions 40, as shown in fig. 9, one bending portion 40 close to the clamp body 7 is inserted into the clamp body 7, corresponding blind holes are formed in opposite positions on the clamp body 7 to accommodate the bending portions 40, and the bending portion 40 close to the rocker arm 8 abuts against one side of the rocker arm 8.

The specific implementation process is as follows: when the rocker arm 8 rotates, the distance between the rocker arm 8 and the clamp body 7 is reduced, the pressure spring receives radial pressure, the bending part 40 receives axial pressure due to the rotation of the rocker arm 8, the rocker arm 8 receives radial and axial acting force after braking is completed, the rocker arm 8 can be reset in a short time, the reset effectiveness of the rocker arm 8 is higher than that of the simple pressure spring, and the use safety of the rear axle body is improved.

The foregoing is merely exemplary of the present utility model, and specific technical solutions and/or features that are well known in the art have not been described in detail herein. It should be noted that, for those skilled in the art, several variations and modifications can be made without departing from the technical solution of the present utility model, and these should also be regarded as the protection scope of the present utility model, which does not affect the effect of the implementation of the present utility model and the practical applicability of the patent. The protection scope of the present application shall be subject to the content of the claims, and the description of the specific embodiments and the like in the specification can be used for explaining the content of the claims.

Claims (5)

1. A rear axle adopting a mechanical disc brake and capable of ensuring constant brake clearance is characterized in that: the brake device is fixedly arranged at the tail end of the half shaft; the braking device comprises a driving turntable and a compensation piece, the compensation piece comprises a first supporting leg, a compensation groove is formed in the end face of the driving turntable, and the first supporting leg is positioned in the compensation groove; the width of the compensating groove is in the range of 0.5-5mm plus the diameter of the first leg.

2. A rear axle employing mechanical disc brake and capable of ensuring constant brake clearance as claimed in claim 1, wherein: the braking device still includes the pincers body and screw rod, and the pincers body includes the inner chamber, and the screw rod is in the inner chamber, and the compensator cover is established on the screw rod and rather than interference fit, and the compensator is first tight spring of wrapping up in, and the screw rod still overlaps and is equipped with the rotation preventing mechanism that makes screw rod unidirectional rotation, and rotation preventing mechanism includes second tight spring and mounting of wrapping up in, and second tightly spring and screw rod interference fit, second tightly spring one end are the second stabilizer blade, and the mounting passes the pincers body and one end is opened there is the spacing groove, and the second stabilizer blade inserts in the spacing groove.

3. A rear axle employing mechanical disc brake and capable of ensuring constant brake clearance as claimed in claim 2, wherein: the brake device is fixed on the rear axle through the fixing mechanism, the fixing mechanism comprises a fixing sleeve, an adapter plate and a U-shaped fixing plate, the fixing sleeve is fixedly connected with the adapter plate through bolts, the U-shaped fixing plate is connected with the adapter plate through bolts, the brake device is fixed on the U-shaped fixing plate, and two ends of the U-shaped fixing plate limit the brake device.

4. A rear axle employing mechanical disc brake and capable of ensuring constant brake clearance as claimed in claim 3, wherein: the periphery of the driving turntable is provided with a stop slot, and a stop pin which limits the driving turntable to rotate only in one direction is arranged, and the stop pin passes through the clamp body and is clamped into the stop slot.

5. The rear axle employing mechanical disc brake and capable of ensuring constant brake clearance as claimed in claim 4, wherein: the end face of the driving turntable is provided with a plurality of driving extrusion grooves which are uniformly distributed in the circumferential direction, rolling bodies are arranged in the driving extrusion grooves, each driving extrusion groove comprises a ball groove and a guide groove, each guide groove comprises a first groove and a second groove, the angles between the first groove and the second groove and the end face of the driving turntable are respectively a first inclination angle and a second inclination angle, the angle range of the first inclination angle is 15-50 degrees, and the angle range of the second inclination angle is 5-40 degrees.

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