Torsion rod spring adjusting arm assembly

Abstract

The invention relates to the technical field of automobiles, and discloses a torsion bar spring adjusting arm assembly which comprises a torsion bar spring, a connecting assembly is arranged at the front end of the torsion bar spring, a mounting sleeve is rotationally connected to the rear end of the torsion bar spring, a buffer box is fixedly connected to the front end of the mounting sleeve, a shaft ring is arranged in the buffer box, and a spring is arranged in the shaft ring. The middle of the shaft ring is fixedly connected with a torsion rod spring through a connecting rod, the shaft ring is symmetrically sleeved with a set of buffering bent pipes, the buffering bent pipes are fixedly connected with a buffering box, pistons are slidably connected into the buffering bent pipes, and the two pistons are fixedly connected with the shaft ring. And the piston divides the interior of the buffer bent pipe into an upper air chamber and a lower air chamber. The service life of the torsion bar spring is prolonged by adding a buffer structure to the torsion bar spring, fatigue cracks are reduced, the vehicle comfort is improved, meanwhile, the design of combining spline teeth and concave hexagonal grooves is adopted, the machining cost and difficulty are reduced, the abrasion condition is improved, and assembling and torque transmission are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of automobiles, in particular to a torsion bar spring adjusting arm assembly. Background Art

[0002] Torsion bar springs, as an elastic element, are widely used in the suspension of modern cars, and are used in cars, trucks and off-road vehicles. Compared with leaf springs, torsion bar springs have a series of advantages: the torsion bar spring has a high energy storage per unit mass, which can reduce the weight of the car and save materials; because the torsion bar spring is fixed to the frame, the unsprung mass is reduced, which is conducive to improving the driving smoothness of the car; when used in the front suspension of front-drive cars, the torsion bar spring can be arranged longitudinally to leave space for the swing half-axle of the front drive axle.

[0003] One end of the torsion bar spring is fixed to the frame, and the other end is connected to the wheel through a swing arm. When the wheel jumps upward after encountering a ground obstacle, the wheel will drive the swing arm to rotate a certain angle around the axis of the torsion bar, causing the torsion bar to twist and deform. At the same time, the elastic deformation energy stored in the torsion bar's twisting deformation will be released when the wheel is free from the obstacle, causing the force transmission mechanism and the wheel to return to their original position quickly.

[0004] However, there are many shortcomings in traditional torsion bar springs. When a vehicle passes through bumps and potholes, the impact force on the wheel is transmitted to the torsion bar spring through the suspension system. The instantaneous large impact will cause the torsion bar spring to produce large stress, and there is a risk of instantaneous overload damage. The vibration during vehicle driving directly acts on the torsion bar spring, which will make it work under high-frequency vibration. In addition, the uneven force on the torsion bar spring under frequent steering, braking and other working conditions will not only easily cause fatigue cracks in the torsion bar spring, but also greatly shorten its fatigue life. Moreover, when subjected to large external forces, the elastic deformation of traditional torsion bar springs is prone to sudden changes, affecting the smoothness of vehicle driving. In addition, if the torsion bar spring lacks buffering during rotation, friction and collision between components will generate noise. The end of the torsion bar spring usually adopts an internal hexagonal structure and a spline structure. When transmitting torque, due to the vibration, impact and repeated torsion of the torsion bar spring during driving, the spline teeth and the internal hexagonal structure are prone to wear. Especially in the case of high load, frequent start and stop or poor road conditions, the wear will be more serious. Once the tooth surface is worn, the fitting clearance of the spline or hexagonal structure will increase, further affecting the fixing effect and force transmission performance of the torsion bar spring. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a torsion bar spring adjusting arm assembly, which solves the problems that the traditional torsion bar spring may be overloaded and damaged, produce fatigue cracks, shorten its service life, affect the ride comfort, produce noise, and the hexagonal and spline structures are easily worn when the car is running and the spring is twisted, thereby affecting its fixing effect and force transmission performance.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a torsion bar spring adjustment arm assembly, including a torsion bar spring, a connecting component is provided at the front end of the torsion bar spring, and a mounting sleeve is rotatably connected to the rear end of the torsion bar spring, a buffer box is fixedly connected to the front end of the mounting sleeve, an axial ring is provided inside the buffer box, the middle part of the axial ring is fixedly connected to the torsion bar spring through a connecting rod, a group of buffer bent pipes are symmetrically sleeved on the axial ring, the buffer bent pipes are fixedly connected to the buffer box, the interior of the buffer bent pipes are slidably connected with pistons, and the two pistons are fixedly connected to the axial rings, and the pistons divide the interior of the buffer bent pipes into an upper air chamber and a lower air chamber, the upper air chamber on the left side is connected to the lower air chamber on the right side through a front connecting pipe, and the lower air chamber on the left side is connected to the lower air chamber on the right side through a rear connecting pipe, and the upper air chamber and the lower air chamber are both filled with compressed air.

[0007] Preferably, the connecting assembly includes an upper control arm, a connecting arm is fixedly connected to the rear side of the upper control arm, a spline groove is provided on the rear side of the connecting arm, a convex hexagonal block is fixedly connected to the inner middle part of the spline groove, a plurality of spline teeth are equidistantly arranged at the front end of the outer wall of the torsion bar spring, a concave hexagonal groove is provided in the front middle part of the torsion bar spring, the plurality of spline teeth are respectively engaged with the corresponding spline grooves, and the concave hexagonal groove is engaged with the convex hexagonal block.

[0008] Preferably, a box cover is provided on the front side of the buffer box, the middle part of the box cover is rotatably connected to the torsion bar spring, and a plurality of side ears are equidistantly provided on the front side of the outer wall of the buffer box and around the box cover, and the corresponding side ears are fixed by fixing bolts.

[0009] Preferably, an adjusting arm bracket is fixedly connected to the mounting sleeve, an adjusting bolt is provided on the adjusting arm bracket, and a cushion block is sleeved on the adjusting bolt.

[0010] Preferably, the tops of the two buffer elbows are connected through a long air pipe, an air valve is provided on one side of the outside of the buffer box, and the inner end of the air valve is connected to the long air pipe.

[0011] Preferably, a pressure chamber is provided on the other side of the outside of the buffer box, the pressure chamber is connected with the long air pipe through the short air pipe, and a tire pressure sensor is provided in the pressure chamber.

[0012] Preferably, the outer wall of the torsion bar spring is provided with a dust cover, and fixing ears are fixedly connected to the corresponding positions of the two sides of the dust cover and the connecting arm, and the corresponding fixing ears are fixed in two phases by fixing bolts, and a sealing plate is fixedly connected to the front side of the dust cover, and the sealing plate is abutted against the notch of the spline groove.

[0013] Preferably, the front connecting tube, the rear connecting tube and the long air tube are all arc-shaped, the outer side of the front connecting tube is fixedly connected to the inner wall of the box cover, and the outer sides of the rear connecting tube and the long air tube are fixedly connected to the inner wall of the buffer box.

[0014] Working principle: Compressed air is injected into the two buffer elbows through the valve mouth and the long air pipe. The compressed air entering the two buffer elbows flows to the upper air chamber and the lower air chamber separated by the piston. When the torsion bar spring is twisted, the connecting rod drives the shaft ring to rotate in the buffer elbow. At this time, the piston connected to the shaft ring slides along the inner wall of the buffer elbow, squeezing the compressed air in the upper air chamber and the lower air chamber to generate elastic reaction force, thereby providing support and buffering for the torsion bar spring. Spline teeth and concave hexagonal grooves are arranged at the front end of the torsion bar spring, and convex hexagonal blocks and spline grooves are arranged at the connection of the connecting arm to allow double engagement and connection between the connecting arm and the torsion bar spring.

[0015] The present invention provides a torsion bar spring adjusting arm assembly, which has the following beneficial effects:

[0016] 1. The present invention arranges a buffer box on the torsion bar spring, utilizes two buffer bends connected by the front connecting pipe and the rear connecting pipe, cooperates with the shaft ring, the piston and the compressed air to realize rotational buffering. When the torsion bar spring faces a momentary large impact, it absorbs a part of the energy, reduces the impact force directly acting on the torsion bar spring, and reduces the risk of damage to the torsion bar spring due to momentary overload. When the vehicle is driving on a bumpy road, the buffer structure can weaken the high-frequency vibration from the road surface, so that the torsion bar spring is in a relatively stable stress environment, and its service life is extended. When the vehicle turns, the buffer structure can adjust the stress angles at both ends of the torsion bar spring to avoid local stress concentration, thereby reducing the fatigue cracks caused by long-term uneven stress and improving the fatigue life of the torsion bar spring. At the same time, the rotational buffer structure cooperates with the torsion bar spring to make the response of the suspension system more linear and smooth, and assists the torsion bar spring to better adjust the suspension stiffness, so that the vehicle can maintain good comfort under various load conditions and reduce the bumpy feeling felt by the occupants of the vehicle.

[0017] 2. The front end of the torsion bar spring of the present invention adopts a design combining spline teeth and concave hexagonal grooves. Compared with simple high-precision splines, the precision requirements of some non-critical dimensions can be appropriately relaxed, because the hexagonal part can play a certain role in auxiliary positioning and force transmission, thereby reducing the overall processing cost and difficulty to a certain extent, and the combined structure can improve the wear condition. The convex hexagonal block part can share part of the axial and circumferential loads and reduce the pressure on the spline tooth surface. The convex hexagonal block and the concave hexagonal groove part provide a relatively easy-to-center reference structure. Compared with simple splines, it is easier to align the torsion bar spring with the frame or control arm during assembly. Moreover, during the assembly process, the hexagonal structure can be used as a preliminary positioning and insertion guide to make the spline assembly smoother. During the dynamic working process, when some tooth surfaces of the spline teeth are unevenly stressed, the convex hexagonal block can balance the torque and reduce the situation of excessive local stress caused by uneven torque transmission. At the same time, the rotation buffer structure can further reduce the wear of the end. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 It is a schematic diagram of the rear structure of the buffer box of the present invention;

[0020] Figure 3 It is a schematic diagram of the explosion structure of the buffer box of the present invention;

[0021] Figure 4 It is a schematic diagram of the internal structure of the buffer box of the present invention;

[0022] Figure 5 It is a schematic diagram of the internal cross-sectional structure of the buffer box of the present invention;

[0023] Figure 6 It is a schematic diagram of the split structure of the connection component of the present invention.

[0024] Figure 7 It is a schematic diagram of the front end structure of the torsion bar spring of the present invention.

[0025] Among them, 1. torsion bar spring; 2. buffer box; 3. box cover; 4. dust cover; 5. upper control arm; 6. connecting arm; 7. adjusting arm bracket; 8. mounting sleeve; 9. valve; 10. pressure chamber; 11. side ear; 12. adjusting bolt; 13. pad; 14. fixing bolt one; 15. buffer elbow; 1501, upper air chamber; 1502, lower air chamber; 16. front connecting pipe; 17. shaft ring; 18. connecting rod; 19. short air pipe; 20. rear connecting pipe; 21. long air pipe; 22. tire pressure sensor; 23. piston; 24. convex hexagonal block; 25. spline groove; 26. spline teeth; 27. fixing bolt two; 28. concave hexagonal groove; 29. ​​fixing ear; 30. sealing plate. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Please refer to the attached Figure 1 -Attached Figure 5The embodiment of the present invention provides a torsion bar spring adjustment arm assembly, including a torsion bar spring 1, a connection component is provided at the front end of the torsion bar spring 1, a mounting sleeve 8 is rotatably connected to the rear end of the torsion bar spring 1, an adjustment arm bracket 7 is fixedly connected to the mounting sleeve 8, so as to adjust the buffer range of the torsion bar spring 1 in two rotation directions, an adjusting bolt 12 is provided on the adjustment arm bracket 7, a cushion block 13 is sleeved on the adjusting bolt 12, a buffer box 2 is fixedly connected to the front end of the mounting sleeve 8, the adjustment arm bracket 7 can adjust the angle of the buffer box 2, a collar 17 is provided inside the buffer box 2, the middle part of the collar 17 is fixedly connected to the torsion bar spring 1 through a connecting rod 18, a group of buffer elbows 15 are symmetrically sleeved on the collar 17, the buffer elbow 15 is fixedly connected to the buffer box 2, the interior of the buffer elbow 15 is slidably connected to a piston 23, and the outer wall of the piston 23 is close to the buffer elbow The inner wall of the tube 15, the two pistons 23 are fixedly connected to the shaft ring 17, the piston 23 divides the interior of the buffer elbow 15 into an upper air chamber 1501 and a lower air chamber 1502, the upper air chamber 1501 on the left side is connected with the lower air chamber 1502 on the right side through the front connecting tube 16, the lower air chamber 1502 on the left side is connected with the lower air chamber 1502 on the right side through the rear connecting tube 20, the upper air chamber 1501 and the lower air chamber 1502 of the left and right buffer elbows 15 are connected through the front connecting tube 16 and the rear connecting tube 20, which plays a role in stabilizing and balancing the air pressure, and at the same time allows the supplementary compressed air to flow to all air chambers, the upper air chamber 1501 and the lower air chamber 1502 are filled with compressed air, the tops of the two buffer elbows 15 are connected through the long air pipe 21, and the valve mouth 9 is arranged on the outer side of the buffer box 2, and the inner end of the valve mouth 9 is connected with the long air pipe 21.

[0028] When the torsion bar spring 1 is twisted, the connecting rod 18 drives the collar 17 to rotate in the buffer elbow 15. At this time, the piston 23 connected to the collar 17 slides along the inner wall of the buffer elbow 15, squeezing the compressed air in the upper air chamber 1501 and the lower air chamber 1502, generating an elastic reaction force, thereby providing support and buffering for the torsion bar spring 1, which is referred to as the rotating buffer structure below. The effect is as follows:

[0029] Reduce instantaneous impact: When the vehicle passes over bumps, potholes and other road conditions, the impact force on the wheel will be transmitted to the torsion bar spring 1 through the suspension system. The traditional torsion bar spring 1 may produce greater stress when facing a large instantaneous impact. The rotating buffer structure can absorb part of the energy at the moment of impact and reduce the impact force directly acting on the torsion bar spring 1. For example, when the vehicle passes over a speed bump at high speed, the buffer structure can reduce the peak impact force on the torsion bar spring 1, thereby reducing the risk of damage to the torsion bar spring 1 due to instantaneous overload.

[0030] Alleviate vibration transmission: If the vibration during vehicle driving is directly transmitted to the torsion bar spring 1, it will cause the torsion bar spring 1 to frequently work under high-frequency vibration, accelerating its fatigue. The rotating buffer structure can play a filtering role and filter out some high-frequency vibrations. For example, when driving on a bumpy road, the buffer structure can weaken the high-frequency vibration from the road surface, so that the torsion bar spring 1 is in a relatively stable force environment, extending its service life.

[0031] Uniform force distribution: During the rotation of the torsion bar spring 1, especially under frequent steering, braking and other working conditions, the force on the torsion bar spring 1 may be uneven. The rotation buffer structure can make the force on the torsion bar spring 1 more uniform during rotation. For example, when the vehicle turns, the buffer structure can adjust the force angles at both ends of the torsion bar spring 1 to avoid local stress concentration, thereby reducing the fatigue cracks caused by long-term uneven force, and improving the fatigue life of the torsion bar spring 1.

[0032] Protect the end connection: The end of the torsion bar spring 1 is prone to wear or loosening due to frequent twisting and stress during operation. The rotation buffer structure adds buffering and protection measures at the end connection position. Ensure the stability of the end connection of the torsion bar spring 1, and further improve the overall reliability and service life.

[0033] Optimize suspension response: When a traditional torsion bar spring 1 is subjected to a large external force, its elastic deformation may suddenly change, affecting the smoothness of the vehicle's ride. The rotation buffer structure cooperates with the torsion bar spring 1 to make the response of the suspension system more linear and smooth. For example, when the vehicle carries different weights (such as fully loaded and unloaded), the buffer structure can assist the torsion bar spring 1 to better adjust the suspension stiffness, so that the vehicle can maintain good comfort under various load conditions and reduce the bumpy feeling felt by the occupants.

[0034] Reduce noise generation: If there is no buffer during the rotation of the torsion bar spring 1, noise may be generated due to friction and collision between components. The rotation buffer structure can effectively reduce the noise generated by the operation of the torsion bar spring 1 and improve the quietness of the vehicle.

[0035] A box cover 3 is provided on the front side of the buffer box 2, and the middle part of the box cover 3 is rotatably connected to the torsion bar spring 1. A plurality of side ears 11 are equidistantly provided on the front side of the outer wall of the buffer box 2 and around the box cover 3, and the corresponding side ears 11 are fixed by fixing bolts 14 to seal the buffer box 2.

[0036] Please see attached Figure 1 , Figure 6 -Attached Figure 7The connection component includes an upper control arm 5, a connecting arm 6 is fixedly connected to the rear side of the upper control arm 5, a spline groove 25 is provided on the rear side of the connecting arm 6, a convex hexagonal block 24 is fixedly connected to the inner middle part of the spline groove 25, a plurality of spline teeth 26 are equidistantly arranged at the front end of the outer wall of the torsion bar spring 1, a concave hexagonal groove 28 is provided in the middle part of the front end of the torsion bar spring 1, a plurality of spline teeth 26 are respectively engaged with the corresponding spline grooves 25, and the concave hexagonal groove 28 is engaged with the convex hexagonal block 24, so that the connecting arm 6 and the torsion bar spring 1 are double engaged and connected.

[0037] Compared with a simple high-precision spline, the precision requirements can be appropriately relaxed, because the hexagonal part can play a certain auxiliary positioning and force transmission role, thereby reducing the overall processing cost and processing difficulty to a certain extent, and the convex hexagonal block 24 and the concave hexagonal groove 28 can share part of the axial and circumferential loads and reduce the pressure on the spline tooth 26 surface. For example, in the initial assembly and under low load conditions, the convex hexagonal block 24 and the concave hexagonal groove 28 can be used as the main force transmission structure to reduce the wear of the spline tooth 26 surface. For fatigue damage, due to the dispersion of the load, the stress concentration at the root of the spline tooth 26 will be reduced, and it is easier to align the torsion bar spring 1 with the connecting arm 6 during assembly. During the assembly process, the convex hexagonal block 24 and the concave hexagonal groove 28 can be used as a preliminary positioning and insertion guide to make the assembly of the torsion bar spring 1 smoother. In terms of torque transmission, the combined structure can make the torque transmission more uniform. In the combined structure, since the convex hexagonal block 24 and the concave hexagonal groove 28 are not the only force transmission and assembly structures, the problem of edge wear can be alleviated to a certain extent. In terms of tool matching, this structure can cooperate with the hexagonal part without affecting the spline part, and has higher adaptability.

[0038] An adjusting arm bracket 7 is fixedly connected to the mounting sleeve 8, an adjusting bolt 12 is provided on the adjusting arm bracket 7, a pad 13 is sleeved on the adjusting bolt 12, a pressure chamber 10 is provided on the other side of the outside of the buffer box 2, the pressure chamber 10 is connected to the long air pipe 21 through a short air pipe 19, and a tire pressure sensor 22 is provided in the pressure chamber 10 for monitoring the air pressure in the buffer bend 15.

[0039] The front connecting tube 16, the rear connecting tube 20 and the long air tube 21 are all arc-shaped. The outer side of the front connecting tube 16 is fixedly connected to the inner wall of the box cover 3, and the outer sides of the rear connecting tube 20 and the long air tube 21 are fixedly connected to the inner wall of the buffer box 2. Fixing the front connecting tube 16 and the rear connecting tube 20 can prevent the pipeline from interfering with the torsion of the torsion bar spring 1, and also protect the front connecting tube 16 and the rear connecting tube 20 from being worn.

[0040] The outer wall of the torsion bar spring 1 is provided with a dust cover 4, and the two sides of the dust cover 4 and the corresponding positions of the connecting arm 6 are fixedly connected with fixing ears 29, and the corresponding fixing ears 29 are fixed by fixing bolts 27. The front side of the dust cover 4 is fixedly connected with a sealing sheet 30, and the sealing sheet 30 is abutted against the notch of the spline groove 25 to prevent dust from entering the connection between the torsion bar spring 1 and the connecting arm 6.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A torsion bar spring adjusting arm assembly, comprising a torsion bar spring (1), characterized in that: The front end of the torsion bar spring (1) is provided with a connection assembly, the rear end of the torsion bar spring (1) is rotatably connected with a mounting sleeve (8), the front end of the mounting sleeve (8) is fixedly connected with a buffer box (2), the buffer box (2) is provided with an axial collar (17), the middle part of the axial collar (17) is fixedly connected with the torsion bar spring (1) through a connecting rod (18), a group of buffer elbows (15) are symmetrically sleeved on the axial collar (17), the buffer elbows (15) are fixedly connected with the buffer box (2), and the interior of the buffer elbows (15) are slidably connected with movable The two pistons (23) are fixedly connected to the shaft ring (17), and the pistons (23) divide the interior of the buffer elbow (15) into an upper air chamber (1501) and a lower air chamber (1502). The upper air chamber (1501) on the left is connected to the lower air chamber (1502) on the right through the front connecting pipe (16), and the lower air chamber (1502) on the left is connected to the lower air chamber (1502) on the right through the rear connecting pipe (20). The upper air chamber (1501) and the lower air chamber (1502) are both filled with compressed air.

2. The torsion bar spring adjusting arm assembly according to claim 1, characterized in that: The connection assembly comprises an upper control arm (5), the rear side of the upper control arm (5) is fixedly connected to a connecting arm (6), the rear side of the connecting arm (6) is provided with a spline groove (25), the inner middle part of the spline groove (25) is fixedly connected to a convex hexagonal block (24), the front end of the outer wall of the torsion bar spring (1) is equidistantly provided with a plurality of spline teeth (26), the front middle part of the torsion bar spring (1) is provided with a concave hexagonal groove (28), the plurality of spline teeth (26) are respectively engaged with the corresponding spline grooves (25), and the concave hexagonal groove (28) is engaged with the convex hexagonal block (24).

3. The torsion bar spring adjusting arm assembly according to claim 1, characterized in that: A box cover (3) is arranged on the front side of the buffer box (2), the middle part of the box cover (3) is rotatably connected to the torsion bar spring (1), and a plurality of side ears (11) are equidistantly arranged on the front side of the outer wall of the buffer box (2) and around the box cover (3), and the corresponding side ears (11) are fixed by fixing bolts (14).

4. The torsion bar spring adjusting arm assembly according to claim 1, characterized in that: The mounting sleeve (8) is fixedly connected to an adjustment arm bracket (7), an adjustment bolt (12) is provided on the adjustment arm bracket (7), and a cushion block (13) is sleeved on the adjustment bolt (12).

5. The torsion bar spring adjusting arm assembly according to claim 1, characterized in that: The tops of the two buffer elbows (15) are connected via a long air pipe (21), an air valve (9) is arranged on one side of the outside of the buffer box (2), and the inner end of the air valve (9) is connected to the long air pipe (21).

6. The torsion bar spring adjusting arm assembly according to claim 5, characterized in that: A pressure chamber (10) is provided on the other side of the outside of the buffer box (2), the pressure chamber (10) is connected to the long air pipe (21) via a short air pipe (19), and a tire pressure sensor (22) is provided in the pressure chamber (10).

7. The torsion bar spring adjusting arm assembly according to claim 2, characterized in that: The outer wall of the torsion bar spring (1) is provided with a dust cover (4), and the two sides of the dust cover (4) and the corresponding positions of the connecting arm (6) are fixedly connected with fixing ears (29), and the corresponding fixing ears (29) are fixed by fixing bolts (27). The front side of the dust cover (4) is fixedly connected with a sealing sheet (30), and the sealing sheet (30) abuts against the notch of the spline groove (25).

8. The torsion bar spring adjusting arm assembly according to claim 3, characterized in that: The front connecting pipe (16), the rear connecting pipe (20) and the long air pipe (21) are all arc-shaped; the outer side of the front connecting pipe (16) is fixedly connected to the inner wall of the box cover (3); and the outer sides of the rear connecting pipe (20) and the long air pipe (21) are fixedly connected to the inner wall of the buffer box (2).

Images