CN115534697A

CN115534697A - Emergency device for brake failure of new energy automobile

Info

Publication number: CN115534697A
Application number: CN202211307959.0A
Authority: CN
Inventors: 洪建军
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-09-28
Filing date: 2022-10-24
Publication date: 2022-12-30

Abstract

The invention relates to the technical field of braking, and discloses an emergency device for brake failure of a new energy automobile. The invention has the following advantages and effects: the traction force source comprises a plurality of motors and speed reducers, so that the stepped speed reduction can be realized, and the safety of drivers and passengers can be better ensured under the condition that the brake of the electric automobile fails.

Description

Emergency device for brake failure of new energy automobile

Technical Field

The invention relates to the technical field of electric automobile braking, in particular to an emergency device for brake failure of a new energy automobile.

Background

The electric automobile is a vehicle which takes a vehicle-mounted power supply and the like as power and drives wheels to run by using a motor, and meets various requirements of road traffic and safety regulations. Because the influence on the environment is smaller than that of the traditional automobile, the prospect is widely seen. At present, the electric automobile is frequently exposed to brake failure in the driving process, the life and property safety of drivers and passengers can be greatly threatened when the brake failure occurs, and traffic safety accidents are easily caused. The electric automobile brake system has the following characteristics that because the electric automobile does not have an engine structure of a fuel automobile, vacuum assistance cannot be generated through the work of the engine, and an electronic vacuum pump needs to be designed to provide vacuum. Compared with a mechanical vacuum pump, the electronic vacuum pump structure is more complex in gas circuit design, needs to be added with a software strategy of a vacuum pump control module, hardware circuit design, diagnosis of a control module, interpersonal interaction interface design and the like, is more complex in structure, has higher failure probability, and can not provide assistance once the failure occurs, a driver hardly steps on a brake pedal. Some electric vehicles adopt an electronic power-assisted control brake system, but an electric control system has the possibility of failure, and once the electric vehicle is powered off or a computer of the electric vehicle is halted and the like, the brake system can also completely fail.

Disclosure of Invention

The invention aims to provide an emergency device for brake failure of a new energy automobile, which has the effect of reducing the speed of the automobile when the brake of the electric automobile fails.

The technical purpose of the invention is realized by the following technical scheme: the emergency device for brake failure of the new energy automobile comprises a driven shaft, a combining device, an operating device, a brake shaft and a traction source, wherein the driven shaft is connected with a differential mechanism of the electric automobile, the operating device is used for driving the combining device to combine the driven shaft with the brake shaft, and the traction source is connected with the brake shaft.

Through adopting above-mentioned technical scheme, the driven shaft is connected on differential mechanism, and the driven shaft idle running when electric automobile goes, and the brake shaft does not rotate. After the original brake fails in the running process of the electric automobile, a driver drives the combining device to work through the mechanical operating device, the driven shaft is combined with the brake shaft after the combining device works, and after the driven shaft drives the brake shaft to rotate, the traction force source provides traction force required by braking, so that the electric automobile is decelerated and braked.

The invention is further configured as follows: the source of traction includes one or more motors.

By adopting the technical scheme, the traction force source can be one motor or a plurality of motors. Taking two motors as an example, the power of the two motors is different, the braking effect of the traction force provided by the small motor is equivalent to the deceleration of the domestic small bridge vehicle 5 at the 3-gear level, and the braking effect of the traction force provided by the high-power motor is equivalent to the deceleration of the domestic small bridge vehicle 5 at the 1-gear level. When the electric automobile runs at a high speed, the low-power motor provides traction. When the electric automobile runs at a low speed, a high-power motor provides traction.

The invention is further provided with: the motor includes shell, stator, rotor, a plurality of elastic component, the stator can the shell internal rotation, elastic component elasticity acts on in order to order about the stator return after the rotation on the stator, the shell is equipped with the perforation, the stator articulates there is the moving part, the moving part passes be located behind the perforation the shell is outside, the moving part is connected with wire drawing mechanism, wire drawing mechanism is used for pulling former car brake pedal.

Through adopting above-mentioned technical scheme, when electric automobile's vacuum servo system broke down and can't provide the helping hand, the motor is when providing traction force, and the stator receives resistance back and rotates, and then drives the moving part swing, and the moving part passes through the original car brake pedal of stay wire mechanism pulling and pushes down, plays the effect of providing the brake helping hand.

The invention is further provided with: the movable part comprises a crank hinged to the stator and a connecting rod hinged to the crank, the crank penetrates through the through hole, the wire pulling mechanism comprises a support, a movable seat movably arranged on the support and a first pulling wire, the connecting rod is hinged to the movable seat, one end of the first pulling wire is fixed on the movable seat, and the other end of the first pulling wire is used for driving the brake pedal to move.

The invention is further provided with: the brake pedal is characterized in that a first elastic device is arranged on the first pull wire, the first elastic device comprises a first cylinder, a first piston and a first spring, two ends of the first spring are respectively connected to the first cylinder and the first piston, the first pull wire is connected to the first piston, and the first cylinder is connected to the brake pedal through a first connecting rope.

By adopting the technical scheme, if the first stay wire is directly connected and fixed with the brake pedal, the acting force exerted by the rotation of the brake pedal of the first stay wire may exceed the maximum bearing force of the original master cylinder, so that the master cylinder and other parts are damaged. The first elastic device is arranged on the first pull wire, and the elastic force of the first spring does not exceed the maximum bearing force of the original brake master cylinder, so that the brake master cylinder is prevented from being damaged due to the excessive assistance provided.

The invention is further provided with: the traction source comprises a middle shaft, a small gear and a large gear, the middle shaft is shared by a plurality of motors, the small gear is fixedly arranged on the middle shaft, the large gear is arranged on the brake shaft or a combining device, and the large gear is meshed with the small gear.

The invention is further provided with: the combination device comprises a brake disc fixed on a driven shaft, a casing fixed on the brake shaft, a fixing part, a shifting fork hinged to the fixing part, a bearing and an operating device, wherein the casing is sleeved on the brake disc, a notch is formed in the end face of the casing, a brake pad is arranged in the notch, an inner ring and an outer ring of the bearing are respectively in contact with the shifting fork and the brake pad, and the operating device is used for driving the shifting fork to swing.

Through adopting above-mentioned technical scheme, when needs combination device during operation, operating means orders about the shift fork swing, and the shift fork passes through the bearing and promotes the brake block and leans on tight brake disc, drives the brake block motion when the brake disc is rotatory, and the brake block acts on the notch inner wall and drives the cover shell and rotate, and the cover shell drives the brake shaft and rotates, realizes combining driven shaft and brake shaft.

The operating device drives the shifting fork to swing and to be far away from the brake block, acting force between the brake block and the brake disc is reduced or even disappears, friction force between the brake block and the brake disc is small or even disappears, and the function of removing the combination of the driven shaft and the brake shaft is achieved.

The gearwheel can be mounted on the brake shaft or on the circumferential outer wall of the housing between the release bearings.

The invention is further provided with: first direction inclined plane has been seted up to the notch, the brake block receives behind the brake disc frictional force first direction inclined plane direction the brake disc leans on tightly the brake disc.

Through adopting above-mentioned technical scheme, the brake block motion is driven when the brake disc is rotatory, and first direction inclined plane is unanimous with brake block motion trend, and the direction brake block leans on tight brake disc. Only need the shift fork to keep applying the effort back through the bearing to the brake block, under the effect on first direction inclined plane, the brake block only can lean on more and more tightly the brake disc, hardly separates with the brake disc, guarantees to possess good quick combination effect between driven shaft and the braking axle.

The invention is further provided with: the brake shoe is characterized in that a plurality of notches are formed in two ends of the casing, two shifting forks are arranged on two sides of each casing, a cam is further arranged between the two shifting forks, the shifting forks are abutted to the curved surfaces of the cam, return springs are further connected between the two shifting forks, the operating device drives the cam to rotate to drive the two shifting forks to swing, the bearings are two release bearings, each bearing is located between the shifting forks and the brake pads, and the bearing sleeves are in clearance fit on the brake shafts.

Through adopting above-mentioned technical scheme, notch, brake block distribute in brake disc both sides, and the brake block can combine better with the brake disc, makes driven shaft and brake axle also can realize combining better.

The cam rotates to drive the two pushing bearings to move, and then acting force is applied to the brake block to enable the brake block to be tightly attached to the brake disc. The cam rotates reversely, the two shifting forks reset under the elastic force action of the return springs, the acting force applied to the brake pads is reduced, the friction force between the brake pads and the brake disc is reduced or even disappears, and at the moment, the driven shaft and the brake shaft are disengaged.

The invention is further configured as follows: operating means includes operating portion, second stay wire, second resilient means, the operating portion is in traditional manual brake, straight pull formula manual brake, foot-operated manual brake one kind, second resilient means includes second barrel, second piston, second spring, the second spring both ends are supported respectively on second piston and second barrel, the second stay wire both ends are fixed respectively the operating portion with on the second piston, the second barrel is fixed in through the second connecting rod the cam perhaps on the shift fork.

Through adopting above-mentioned technical scheme, if directly act as go-between the second and connect on the cam, the driver though can drive cam, shift fork motion through the second is acted as go-between, but can have following problem: the driver can not hold the stay wire continuously all the time, the operating device can keep the stay wire after pulling, and in the process, the brake pad can continue to be close to the brake disc under the combined action of friction force and the first guide inclined plane, so that gaps can be formed among the shifting fork, the bearing and the brake pad, and the bearing can shake and collide. According to the invention, the second pull wire is designed to pull the second piston to move, the second piston drives the second cylinder and the second connecting rod to move through the second spring, and then the cam is pulled to rotate, so that even if the brake pad is close to the brake disc under the combined action of friction force and the first guide inclined plane when the pull wire is in a position keeping state, after a gap is formed among the shifting fork, the bearing and the brake disc, the spring which is elastically deformed can release the elastic force to drive the cam and the shifting fork to move, and the formed gap is eliminated.

The invention has the beneficial effects that:

1. the invention works after the manual start when the electric automobile brake fails, the driven shaft and the brake shaft are combined through the combination device, and the traction force required by the brake is provided through the traction force source, so that the speed reduction and the brake of the electric automobile are realized, and the life and property safety of drivers and passengers of the electric automobile is ensured to the greatest extent.

2. When the electric automobile brake system works, the angle of the motor stator of the traction force source is changed, and the brake pedal of the electric automobile is pulled through the movable part and the wire pulling mechanism to provide assistance, so that the original brake system of the electric automobile is restored to normal work. The internal elasticity of the first elastic device in the wire pulling mechanism does not exceed the maximum bearing capacity of the original brake master cylinder, so that the damage of a brake system caused by the excessive assistance is avoided.

3. The combination device enlarges the combination site between the combination device and the brake disc through a plurality of brake pads; the first direction inclined plane of notch inner wall for the shift fork passes through the bearing and applys certain effort for the brake block, and first direction inclined plane receives under the cooperation of frictional force at the brake block, and the brake block can only constantly lean on tight brake disc, makes and keeps very excellent combination effect between brake block and the brake disc.

4. The traction force source comprises a plurality of motors, can realize graded speed reduction, and can better ensure the safety of drivers and passengers under the condition of brake failure of the electric automobile.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural view of example 1.

Fig. 2 is a schematic view of the positional relationship among the driven shaft, the brake shaft, and the housing in embodiment 1.

FIG. 3 is a schematic view showing the structural relationship among the brake pad, the brake disc and the housing in example 1.

Fig. 4 is a schematic structural view of a cam and a second elastic device in embodiment 1.

Fig. 5 is a schematic structural view of the wire pulling mechanism of embodiment 1.

Fig. 6 is a schematic view of the motor structure of embodiment 1.

Fig. 7 is a schematic structural view of the elastic member of embodiment 1.

Fig. 8 is a schematic structural view of a first resilient means and a brake pedal according to embodiment 1.

Fig. 9 is a schematic structural view of a first elastic device according to embodiment 1.

Fig. 10 is a schematic view of the structure of the jacket of embodiment 5.

In the figure, 1, a driven shaft; 11. a bevel gear; 2. a bonding device; 21. a brake disc; 22. a housing; 221. a notch; 222. a first guide slope; 23. a shifting fork; 24. a bearing; 25. an operating device; 251. an operation unit; 252. a second pull wire; 253. a second elastic device; 2531. a second cylinder; 2532. a second piston; 2533. a second spring; 2534. a second connecting rod; 26. a brake pad; 261. a second guide slope; 27. a cam; 28. a return spring; 3. a brake pedal; 4. a brake shaft; 41. a bull gear; 5. a motor; 51. a housing; 511. perforating; 512. a movable groove; 52. a stator; 53. a rotor; 54. an elastic component; 541. a sleeve; 542. a third spring; 543. a piston rod; 544. a connecting spring; 55. a movable member; 551. a crank; 552. a connecting rod; 56. a middle shaft; 561. a pinion gear; 6. a wire pulling mechanism; 61. a support; 62. a movable seat; 63. a first pull wire; 64. a first elastic device; 641. a first cylinder; 642. a first piston; 643. a first spring; 644. a first connecting cord; 7. a differential mechanism; 71. a ring gear.

Detailed Description

The technical solution of the present invention will be clearly and completely described with reference to the specific embodiments. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

Example 1: an emergency device for brake failure of a new energy automobile comprises a driven shaft 1, a combining device 2, a brake shaft 4, a traction source and a fixing part, wherein an electric automobile differential 7 comprises a ring gear 71, and the ring gear 71 of the differential 7 is also called a driven gear, a driven ring gear 71, a driven bevel gear 11 and the like and is meshed with a gear on a power input shaft. A bevel gear 11 is fixed to the driven shaft 1, and the bevel gear 11 meshes with the ring gear 71. The combination device 2 comprises two brake discs 21 fixed on the driven shaft 1, two sleeves 22 fixed on the brake shaft 4, four shifting forks 23, four bearings 24 and an operating device 25, wherein the two brake discs 21 correspond to the two sleeves 22 one by one, and the brake discs 21 are positioned inside the sleeves 22. Two shift forks 23 are distributed on both sides of one of the housings 22, and the remaining two shift forks 23 are distributed on both sides of the remaining housing 22. The middle part of the shifting fork 23 is hinged on the fixing part. A plurality of notches 221 are formed in both end faces of the casing 22, a brake pad 26 is arranged in each notch 221, and the plurality of brake pads 26 on the same end face of the casing 22 are connected together. The brake shaft 4 is arranged in a hollow mode, and the driven shaft 1 is inserted into the brake shaft 4. The four bearings 24 are respectively corresponding to the four shifting forks 23 one by one, the bearings 24 are sleeved on the brake shaft 4, and a gap is formed between the inner ring of each bearing 24 and the brake shaft 4. And the bearing 24 is located between the fork 23 and the brake pad 26. The inner and outer races of the bearing 24 abut against the fork 23 and the brake pad 26, respectively.

The notch 221 is provided with a first guiding inclined surface 222, and the brake pad 26 is provided with a second guiding inclined surface 261, which is attached to the first inclined surface. The inner wall of the notch 221 is further formed with a first matching inclined surface, the brake pad 26 is provided with a second matching inclined surface, and the second matching inclined surface is attached to the first matching inclined surface. After the brake pad 26 receives the friction force of the brake disc 21, the first guide inclined plane 222 guides the brake disc 21 to be close to the brake disc 21, and the elastic parts of the brake pad 26 and the shell 22 are used for returning the brake pad

A return spring 28 is connected between the two shifting forks 23, a cam 27 is arranged between the two shifting forks 23, the cam 27 is rotatably connected to the fixed part, and the two shifting forks 23 are pressed against the curved surface of the cam 27 under the driving of the elastic force of the return spring 28. The operating device 25 includes an operating portion 251, a second pulling wire 252, and a second elastic device 253, the operating portion 251 is a hand brake, the second elastic device 253 includes a second cylinder 2531, a second piston 2532, and a second spring 2533, the second piston 2532 and the second spring 2533 are both located in the second cylinder 2531, and two ends of the second spring 2533 are respectively fixed on the second piston 2532 and the second cylinder 2531. One end of the second wire 252 is fixed to the operation portion 251, and the other end is fixed to the second piston 2532. A second connecting rod 2534 is fixed to the second cylinder 2531, and the second connecting rod 2534 is fixed to the cam 27.

The working principle of the combining device 2 is as follows: when the driven shaft 1 and the brake shaft 4 need to be combined, a driver pulls the second pull wire 252 through the operation portion 251, the second pull wire 252 drives the second piston 2532, the second cylinder 2531 and the second connecting rod 2534 to move, the second spring 2533 generates elastic deformation, the second connecting rod 2534 drives the cams 27 to rotate, each cam 27 drives the two shifting forks 23 to swing, the shifting forks 23 push the bearings 24 and the brake pads 26 to move, the brake pads 26 generate friction force after contacting the brake disc 21, and the brake pads 26 further lean against the brake disc 21 under the guidance of the first guide inclined surface 222. The rotating driven shaft 1 and the brake disc 21 drive the brake shaft 4 to rotate through the brake pad 26 and the sleeve 22, so that the driven shaft 1 and the brake shaft 4 are combined.

When the coupling state of the driven shaft 1 and the brake shaft 4 needs to be released, after the operating part 251 releases the second pull wire 252, the two shift forks 23 swing under the elastic force of the return spring 28, and the cam 27 also returns and rotates after receiving the acting force of the shift fork 23. The swinging fork 23 is far away from the brake pad 26, so that the acting force applied to the brake pad 26 is reduced, and after the acting force between the brake pad 26 and the brake disc 21 is reduced, the friction force between the brake pad 26 and the brake disc is reduced or even disappears, and the combination state of the driven shaft 1 and the brake shaft 4 is released.

The braking shaft 4 is connected with a traction source which comprises a middle shaft 56 and two motors 5, the middle shaft 56 is fixed with a small gear 561, the large gear and the small gear are collectively called a speed reducer, the braking shaft 4 is fixed with a large gear 41, and the large gear 41 is meshed with the small gear 561. The two motors 5 share a central shaft 56 and have different powers. The motor 5 comprises a shell 51, a rotor 53 and a stator 52, wherein the rotor 53 is arranged on a middle shaft 56, the stator 52 is arranged on the shell 51 through a needle bearing 24, and a plurality of elastic assemblies 54 are arranged between the stator 52 and the shell 51. The shell 51 is provided with a movable ball which can rotate on the shell 51, and the movable ball is provided with a through hole 511. The stator 52 is provided with a movable part 55, the movable part 55 comprises a crank 551 and a connecting rod 552, one end of the crank 551 is hinged to the stator 52, and the other end of the crank 551 passes through the through hole 511 and is located outside the housing 51. The movable member 55 is connected to a wire pulling mechanism 6, the wire pulling mechanism 6 includes a bracket 61, a movable base 62 movably disposed on the bracket 61, and a first wire pulling 63, one end of the connecting rod 552 is hinged to the crank 551, and the other end is hinged to the movable base 62. One end of the first wire 63 is fixed to the movable base 62, and the other end is provided with a first elastic device 64, the first elastic device 64 includes a first cylinder 641, a first piston 642 and a first spring 643, the first piston 642 and the first spring 643 are both located in the first cylinder 641, and two ends of the first spring 643 are respectively fixed to the first piston 642 and the first cylinder 641. The first extension is fixed with first piston 642. A first connecting rope 644 is fixed to the first cylinder 641, and the first connecting rope 644 is fixed to the brake pedal 3.

The elastic assembly 54 includes a sleeve 541, a third spring 542 disposed in the sleeve 541, and a piston rod 543 inserted into the sleeve 541, wherein one end of the third spring 542 is fixed on an inner wall of the sleeve 541 and the other end is fixed on the piston rod 543. The housing 51 has a movable groove 512, the sleeve 541 is inserted into the movable groove 512, and the piston rod 543 is hinged to the stator 52. A connection spring 544 is disposed between the sleeve 541 and the housing 51, and the connection spring 544 elastically retains the sleeve 541 in the movable groove 512.

The working principle is as follows: in the normal running process of the electric automobile, the ring gear 71 in the differential 7 drives the driven shaft 1 to idle, and the brake shaft 4 does not rotate.

After the original brake of the electric automobile fails, a driver enables the driven shaft 1 to be combined with the brake shaft 4 through the operating device 25, the driven shaft 1 drives the brake shaft 4 to rotate, the brake shaft 4 drives the middle shaft 56 to rotate, and the rotor 53 on the middle shaft 56 rotates under resistance, so that the motor 5 provides resistance to form traction force, the brake shaft 4, the driven shaft 1 and the differential mechanism 7 are provided with brake resistance, and meanwhile, the original automobile power output is turned off, so that the electric automobile is decelerated.

The stator 52 of the motor 5 rotates after being stressed, the moving seat 62 is driven to move by the crank 551 and the connecting rod 552, the moving seat 62 drives the first piston 642 and the first cylinder 641 to move by the first pull wire 63, the first cylinder 641 drives the brake pedal 3 to press down by the first connecting rope 644, and when the brake fails due to the failure of the electronic power-assisted system, the brake system can provide power assistance and automatic brake, so that the original brake system of the automobile can work normally.

Example 2: the emergency device for the brake failure of the new energy automobile is different from the emergency device in embodiment 1 in that the operating part 251 is a straight pull type hand brake.

Example 3: the emergency device for brake failure of the new energy automobile is different from the emergency device in embodiment 1 in that an operation part 251 is a pedal type hand brake.

Example 4: the difference between the emergency device for the brake failure of the new energy automobile and the embodiment 1 is that the transmission between a crank 551 and a brake pedal 3 can also be realized in a hydraulic mode.

Example 5: an emergency device for brake failure of a new energy automobile is different from the embodiment 1 in that a large gear 41 is not mounted on a brake shaft 4, but on the outer wall of the circumferential surface of a casing 22 between release bearings 24, as shown in fig. 10.

Claims

1. The utility model provides a new energy automobile brake malfunctioning emergency device which characterized in that: the electric vehicle differential mechanism comprises a driven shaft (1), a combining device (2), an operating device (25), a braking shaft (4) and a traction source, wherein the driven shaft (1) is connected with an electric vehicle differential mechanism (7), the operating device (25) is used for driving the combining device (2) to combine the driven shaft (1) with the braking shaft (4), and the traction source is connected with the braking shaft (4).

2. The emergency device for the brake failure of the new energy automobile according to claim 1, characterized in that: the source of traction force comprises one or more electric motors (5).

3. The emergency device for the brake failure of the new energy automobile according to claim 2, characterized in that: the motor (5) comprises a shell (51), a stator (52), a rotor (53) and a plurality of elastic components (54), wherein the stator (52) can rotate in the shell (51), the elastic components (54) elastically act on the stator (52) to drive the stator (52) to return after rotation, the shell (51) is provided with a through hole (511), the stator (52) is hinged with a movable piece (55), the movable piece (55) penetrates through the through hole (511) and then is located outside the shell (51), the movable piece (55) is connected with a wire drawing mechanism (6), and the wire drawing mechanism (6) is used for drawing an original brake pedal (3).

4. The emergency device for the brake failure of the new energy automobile according to claim 3, characterized in that: the movable piece (55) comprises a crank (551) hinged to the stator (52) and a connecting rod (552) hinged to the crank (551), the crank (551) penetrates through the through hole (511), the wire pulling mechanism (6) comprises a support (61), a moving seat (62) movably arranged on the support (61), and a first wire pulling (63), the connecting rod (552) is hinged to the moving seat (62), one end of the first wire pulling (63) is fixed to the moving seat (62), and the other end of the first wire pulling (63) is used for driving the brake pedal (3) to move.

5. The emergency device for the brake failure of the new energy automobile according to claim 2, 3 or 4, characterized in that: the brake pedal is characterized in that a first elastic device (64) is arranged on the first pull wire (63), the first elastic device (64) comprises a first cylinder (641), a first piston (642) and a first spring (643), two ends of the first spring (643) are respectively connected to the first cylinder (641) and the first piston (642), the first pull wire (63) is connected with the first piston (642), and the first cylinder (641) is connected with the brake pedal (3) through a first connecting rope (644).

6. The emergency device for brake failure of the new energy automobile according to claim 2, 3 or 4, characterized in that: the traction source comprises a middle shaft (56), a small gear (561) and a large gear (41), the motors (5) share the middle shaft (56), the small gear (561) is fixedly installed on the middle shaft (56), the large gear (41) is installed on the brake shaft (4) or the large gear (41) is installed on the combining device (2), and the large gear (41) is meshed with the small gear (561).

7. The emergency device for brake failure of the new energy automobile according to claim 1, 2, 3 or 4, characterized in that: combining device (2) including fix brake disc (21) at driven shaft (1), fix cover shell (22), the fixed part in brake shaft (4), articulate in shift fork (23), bearing (24), operating means (25) of fixed part, cover shell (22) cover is in on brake disc (21), notch (221) has been seted up to cover shell (22) terminal surface, be equipped with brake block (26) in notch (221), the outer lane contacts respectively in bearing (24) shift fork (23) with brake block (26), operating means (25) are used for driving shift fork (23) swing.

8. The emergency device for the brake failure of the new energy automobile according to claim 7, characterized in that: the notch (221) is provided with a first guide inclined surface (222), and the brake disc (21) is guided to be close to the brake disc (21) by the first guide inclined surface (222) after the brake disc (26) is subjected to the friction force of the brake disc (21).

9. The emergency device for the brake failure of the new energy automobile according to claim 7 or 8, characterized in that: the brake shoe is characterized in that a plurality of notches (221) are formed in two ends of the casing (22), two shift forks (23) are arranged on two sides of each casing (22), a cam (27) is further arranged between the two shift forks (23), the shift forks (23) are abutted to the curved surface of the cam (27), two return springs (28) are further connected between the two shift forks (23), an operating device (25) drives the cam (27) to rotate to drive the two shift forks (23) to swing, two bearings (24) are separated bearings (24) and are arranged in two quantities, each bearing (24) is located between the two shift forks (23) and the brake pads (26), and the bearing (24) is sleeved on the brake shaft (4) and is in clearance fit.

10. The emergency device for the brake failure of the new energy automobile according to claim 9, characterized in that: the operating device (25) comprises an operating part (251), a second pull wire (252) and a second elastic device (253), the operating part (251) is one of a traditional handbrake, a straight pull type handbrake and a pedal type handbrake, the second elastic device (253) comprises a second cylinder (2531), a second piston (2532) and a second spring (2533), two ends of the second spring (2533) are respectively abutted to the second piston (2532) and the second cylinder (2531), two ends of the second pull wire (252) are respectively fixed on the operating part (251) and the second piston (2532), and the second cylinder (2531) is fixed on the cam (27) or the shifting fork (23) through a second connecting rod (2534).