Transmission power assisting device

Abstract

The invention discloses a transmission power assisting device which comprises a motor, a coupler, a ball screw, an anti-rotation sleeve, a piston and a cylinder body, the motor further comprises a shell, a bearing, a rotor and a stator, the coupler further comprises a coupler ball socket, a coupler taper sleeve, a coupler pawl and a coupler flexible material pad, the thickness of the coupler flexible material pad is 0.2-0.4 mm, and the elastic modulus of the coupler flexible material pad is 23-32 GPa; the ball screw further comprises a lead screw, a nut and a limiting key. Flexible connection is added between the lead screw of the ball screw and the motor hollow shaft, so that the piston can be better coaxial with the cylinder body in the moving process, lateral force borne by the cylinder body and the leather cup is reduced or eliminated, and therefore abnormal sound is avoided.

Description

Technical Field

[0001] This application relates to automotive transmission technology, and particularly to a transmission assist device. Background Art

[0002] An assist device is a control device in an automobile that uses compressed air, high-pressure oil, etc. to achieve the purpose of easy use. Taking a transmission assist servo braking system as an example, its characteristic is that the control device of the servo system is directly manipulated by the brake pedal mechanism, and its output force acts on the hydraulic master cylinder, pressurizing the hydraulic fluid in the master cylinder together with the pedal force, which is different from the supercharging servo braking system. The characteristic of the supercharging servo braking system is that the brake pedal mechanism controls the brake master cylinder, the hydraulic pressure output by the master cylinder is transmitted to the auxiliary cylinder, and the servo system is controlled. The output force of the servo system and the master cylinder hydraulic pressure act on the auxiliary cylinder together, and the hydraulic pressure output from the auxiliary cylinder to the wheel cylinder is much higher than the master cylinder hydraulic pressure. Therefore, the transmission assist device is quite important for a vehicle. Summary of the Invention

[0003] In view of this, the embodiments of this application are expected to provide a transmission device to solve at least the above technical problems.

[0004] To achieve the above object, the technical solution of this application is realized as follows:

[0005] The embodiments of this application provide a transmission assist device, including a motor, a coupling, a ball screw, an anti-rotation sleeve, a piston and a cylinder block. The motor includes a housing, bearings, a rotor and a stator. The coupling includes a coupling ball socket, a coupling cone sleeve, a coupling pawl and a coupling flexible material pad. The thickness of the coupling flexible material pad is 0.2 - 0.4 mm, and its elastic modulus is 23 - 32 GPa. Among them,

[0006] One end of the screw rod is provided with a rod handle, and the end of the rod handle away from the screw rod body is a ball head; the rod handle of the screw rod passes through the inner ring of the coupling pawl;

[0007] The coupling flexible material pad is installed on the outer ring of the coupling pawl, and the coupling flexible material pad is press-fitted into the coupling cone sleeve with an interference fit; the coupling ball socket matches and connects with the ball head of the screw rod handle, and there is a swing angle between the coupling ball socket and the screw rod handle; the coupling cone sleeve is connected with the coupling ball socket, and the coupling cone sleeve is connected with the rotor of the motor;

[0008] The coupling pawl is provided with 4 first pawls. The lead screw shank passes through the inner ring formed by the central ring of the coupling pawl, and the lead screw shank is connected to the coupling pawl by riveting; at corresponding positions on the inner wall of the coupling flexible material pad, there are provided first pawl grooves with the same number as the first pawls of the coupling pawl, and the shape of the first pawl groove is the same as the shape of the first pawl; on the outer wall of the coupling flexible material pad, there are provided 4 second pawl grooves, and the second pawl grooves and the first pawl grooves are arranged alternately. One side cross-section of the coupling cone sleeve is in a circular ring shape, the inner diameter of the circular ring of the coupling cone sleeve matches the outer diameter of the coupling flexible material pad, and at corresponding positions on the inner wall of the coupling cone sleeve, there are provided second pawls with the same number as the second pawl grooves of the coupling flexible material pad, and the shape of the second pawl is the same as the shape of the second pawl groove.

[0009] In some feasible embodiments, the surface of the coupling flexible material pad is coated with a grease with a thickness not higher than 0.1 mm.

[0010] In some feasible embodiments, the grease is a soap-based grease, a hydrocarbon-based grease, or an inorganic grease, and the penetration of the grease is 2 / 25 mm to 13 / 100 mm.

[0011] In some feasible embodiments, the flexible material of the coupling flexible material pad is one of flexible graphite composite material, silicone rubber, felt, chloroprene rubber, nitrile rubber, glass fiber, and plastic polymer.

[0012] In some feasible embodiments, the first pawl, the first pawl groove, the second pawl, and the second pawl groove are located in the same plane.

[0013] In some feasible embodiments, the coupling ball socket is connected to the ball head of the lead screw shank by riveting, and the coupling cone sleeve is connected to the coupling ball socket by riveting;

[0014] The piston is pressed into the ball screw nut, the anti-rotation sleeve and the cylinder block are fixed on the valve block by riveting, and the limit key of the ball screw nut is installed in the limit groove of the anti-rotation sleeve.

[0015] The transmission assist device provided by the present application, by adding a flexible connection between the lead screw of the ball screw and the hollow shaft of the motor, enables the piston to be better coaxial with the cylinder block during movement, and reduces or eliminates the lateral force received by the cylinder block and the leather cup, thereby avoiding abnormal noise and increasing the service life of the leather cup. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the transmission assist device in the present application;

[0017] Figure 2 This is a schematic diagram of a partial structure of the transmission assist device in this application. Detailed implementation manners

[0018] The technical solutions of this application will be further elaborated in detail below in conjunction with the specification drawings and specific embodiments.

[0019] In the various specific technical features described in the various embodiments of the detailed implementation manners, various combinations can be made without contradiction. For example, different implementation manners can be formed by combining different specific technical features. To avoid unnecessary repetition, various possible combination manners of the various specific technical features in this application will not be described separately.

[0020] As Figure 1 、 Figure 2 shown, this transmission assist device is applicable to a braking system and includes a motor 25, a coupling, a ball screw 27, an anti-rotation sleeve 26, a piston 28, a cylinder block 29, a main leather cup 30, and a sub-leather cup 31. The motor further includes a housing 251, a bearing 252, a rotor 253, and a stator. The coupling further includes a coupling ball socket 21, a coupling taper sleeve 23, a coupling pawl 24, and a coupling flexible material pad 32. The ball screw further includes a screw rod 271, a nut 272, and a limit key 273. The thickness of the coupling flexible material pad 32 is 0.2 - 0.4 mm, and its elastic modulus is 23 - 32 GPa. In the embodiments of this application, the selection of the coupling flexible material pad 32 is crucial for the transmission assist device. For the structure of the transmission assist device in the embodiments of this application, for the selected flexible material pad, the buffering effect of general flexible materials is not good. However, the embodiments of this application select a flexible material with a thickness of 0.2 - 0.4 mm and an elastic modulus of 23 - 32 GPa, which can better achieve buffering of the coupling, thereby protecting the coupling and extending its service life. As an example, the flexible material of the coupling flexible material pad is one of flexible graphite composite material, silicone rubber, felt, neoprene, nitrile rubber, glass fiber, and plastic polymer. Among them, the plastic polymer can be polytetrafluoroethylene (PTFE). In the embodiments of this application, the flexible material needs to have good elasticity and wear resistance to be suitable for shock absorption; considering the application environment of the coupling, the flexible material also needs to be high-temperature resistant, oil resistant, and chemically corrosion resistant.

[0021] The surface roughness of the flexible material pad of the coupling in the embodiments of the present application is in the range of Ra 4.3 to Ra 0.95, and a grease with a thickness not higher than 0.1 mm is coated on the surface of the flexible material pad of the coupling. Among them, the grease can be soap-based grease, hydrocarbon-based grease, or inorganic grease, and the penetration requirement of the grease is 2 / 25 mm to 13 / 100 mm. As an example, the soap-based grease includes calcium-based grease, sodium-based grease, and lithium-based grease. In the embodiments of the present application, the penetration requirement of the grease is that at a temperature of 25 °C, the standard cone penetrates vertically into the filled grease by free fall, and the depth reached after 10 seconds is 2 / 25 mm to 13 / 100 mm. As an example, the penetration of the grease is 9 / 100 mm, 1 / 10 mm, or 3 / 25 mm, etc.

[0022] One end of the lead screw 271 is provided with a shank. The shank of the lead screw is a cylinder with a diameter smaller than that of the lead screw body, and the end of the shank away from the lead screw body is a ball head. The shank of the lead screw passes through the inner ring of the coupling pawl 24. The flexible material pad 32 of the coupling is installed on the outer ring of the coupling pawl 24, and the flexible material pad 32 of the coupling is press-fitted into the coupling cone sleeve 23 with an interference fit. The coupling ball socket 21 matches the shape of the ball head of the lead screw shank and is connected together by riveting. There is a swing angle between the coupling ball socket 21 and the lead screw shank. The coupling cone sleeve 23 is connected to the coupling ball socket 21 by riveting, and the coupling cone sleeve 23 is connected to the rotor 253 of the motor.

[0023] The coupling pawl 24 is provided with 4 first pawls 241. The 4 first pawls 241 are connected into one body through a central ring. The 4 first pawls extend outward from the outer edge of the central ring. A circular hole is provided in the center of the central ring to form the inner ring of the coupling pawl 24. The shank of the lead screw passes through the inner ring of the coupling pawl 24, and the shank of the lead screw and the coupling pawl 24 are connected by riveting. By providing 4 first pawls 241, the pawl structure can be symmetrically arranged, making the transmission assist device in the embodiments of the present application more symmetrical and further improving its stability.

[0024] The cross-section of the flexible material pad 32 of the coupling is in an annular shape. The inner diameter of the annular shape matches the outer diameter of the central ring of the coupling pawl 24. Four first pawl grooves 322 are provided at corresponding positions on the inner wall of the flexible material pad 32 of the coupling, which is the same as the number of the first pawls 241 of the coupling pawl 24. The shape of the first pawl groove 322 is the same as the shape of the first pawl 241. Four second pawl grooves 321 are provided on the outer wall of the flexible material pad 32 of the coupling. The number of the second pawl grooves on the outer wall of the flexible material pad 32 of the coupling is not less than 2. In this embodiment, four second pawl grooves are provided. The second pawl grooves 321 and the first pawl grooves 322 are arranged alternately. One side cross-section of the coupling taper sleeve 23 is in an annular shape. The inner diameter of the annular shape of the coupling taper sleeve 23 matches the outer diameter of the flexible material pad 32 of the coupling. Second pawls 231 with the same number as the second pawl grooves 321 of the flexible material pad 32 of the coupling are provided at corresponding positions on the inner wall of the coupling taper sleeve 23. The shape of the second pawl 231 is the same as the shape of the second pawl groove 321. In this embodiment, after the first pawl, the first pawl groove, the second pawl, and the second pawl groove are installed, the cross-section is in the same plane to facilitate the transmission of torque.

[0025] The coupling taper sleeve 23 and the rotor 253 of the motor 25 are connected together by a lock nut 22. The piston 28 is pressed into the nut 272 of the ball screw 27. The anti-rotation sleeve 26 and the cylinder block 29 are fixed on the valve block by riveting. The limit key of the nut 272 of the ball screw 27 is installed in the limit groove of the anti-rotation sleeve 26. The main leather cup 30 and the auxiliary leather cup 31 are installed in the leather cup groove of the cylinder block 29.

[0026] In the transmission assist device in the above embodiment, by adding a flexible connection between the screw rod of the ball screw and the hollow shaft of the motor, the piston can be better coaxial with the cylinder block during movement, and the lateral force on the cylinder block and the leather cup can be reduced or eliminated, thereby avoiding abnormal noise and increasing the service life of the leather cup.

[0027] During the operation of the transmission assist device, first, when the hollow shaft of the motor rotates, the rotor drives the coupling taper sleeve to rotate together. The coupling taper sleeve drives the coupling pawl and the screw rod to rotate simultaneously through the pawl structure. The flexible material pad of the coupling is between the coupling pawl and the coupling taper sleeve, playing a buffering role and enabling the ball screw to have a certain swing angle.

[0028] Due to the rotation of the screw rod, the nut also moves accordingly. At the same time, due to the limiting effect of the anti-rotation sleeve, the nut cannot rotate and can only move linearly, and pushes the piston to move, generating a braking pressure in the cylinder block.

[0029] During the operation of the transmission assist device, since the ball socket of the coupling and the lead screw can swing relative to each other, and the flexible material pad of the coupling can have a certain amount of compressive deformation, together with the restriction of the master cylinder on the piston, a small or no eccentric wear force can be generated between the piston and the master cylinder. This not only prevents frictional noise from occurring between the piston and the cylinder block, but also enables the leather cup in the leather cup groove of the cylinder block to be evenly stressed, thereby extending its service life.

[0030] The above is only the specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A transmission assist device, characterized in that, It includes a motor, a coupling, a ball screw, an anti-rotation sleeve, a piston and a cylinder block. The motor includes a housing, bearings, a rotor and a stator. The coupling includes a coupling ball socket, a coupling cone sleeve, coupling pawls and a coupling flexible material pad. The ball screw includes a screw rod, a nut and a limit key. The thickness of the coupling flexible material pad is 0.2 - 0.4 mm, and its elastic modulus is 23 - 32 GPa; wherein, One end of the screw rod is provided with a rod handle, and the end of the rod handle away from the screw rod body is a ball head; the rod handle of the screw rod is inserted into the inner ring of the coupling pawl; The coupling flexible material pad is installed on the outer ring of the coupling pawl, and the coupling flexible material pad is press-fitted into the coupling cone sleeve with interference; the coupling ball socket matches and connects with the ball head of the screw rod handle, and there is a swing angle between the coupling ball socket and the screw rod handle; the coupling cone sleeve is connected with the coupling ball socket, and the coupling cone sleeve is connected with the rotor of the motor; The coupling pawl is provided with 4 first pawls, and the rod handle of the screw rod passes through the inner ring formed by the central ring of the coupling pawl, and the rod handle of the screw rod is connected with the coupling pawl by riveting; at the corresponding position on the inner wall of the coupling flexible material pad, first pawl grooves with the same number as the first pawls of the coupling pawl are provided, and the shape of the first pawl grooves is the same as the shape of the first pawls; 4 second pawl grooves are provided on the outer wall of the coupling flexible material pad, and the second pawl grooves are arranged alternately with the first pawl grooves. One side cross-section of the coupling cone sleeve is annular, the inner diameter of the annular shape of the coupling cone sleeve matches the outer diameter of the coupling flexible material pad, and at the corresponding position on the inner wall of the coupling cone sleeve, second pawls with the same number as the second pawl grooves of the coupling flexible material pad are provided, and the shape of the second pawls is the same as the shape of the second pawl grooves.

2. The transmission assist device according to claim 1, wherein, The surface roughness of the coupling flexible material pad is between Ra 4.3 and Ra 0.

95.

3. The transmission assist device according to claim 1, wherein, The surface of the coupling flexible material pad is coated with a lubricating grease with a thickness not higher than 0.1 mm.

4. The transmission assistance device according to claim 1, characterized in that, The lubricating grease is a soap-based grease, a hydrocarbon-based grease, or an inorganic grease, and the penetration of the lubricating grease is 2 / 25 mm - 13 / 100 mm.

5. The transmission assist device according to claim 1, characterized in that The flexible material of the coupling flexible material pad is one of flexible graphite composite material, silicone rubber, felt, neoprene, nitrile rubber, glass fiber, and plastic polymer.

6. The transmission assist device according to claim 1, wherein The first pawls, the first pawl grooves, the second pawls and the second pawl grooves are in the same plane.

7. The transmission assist device according to claim 1, wherein, The coupling ball socket is connected with the ball head of the screw rod handle by riveting, and the coupling cone sleeve is connected with the coupling ball socket by riveting; the piston is pressed into the nut of the ball screw, and the anti-rotation sleeve and the cylinder block are fixed on the valve block by riveting, and the limit key of the ball screw nut is installed in the limit groove of the anti-rotation sleeve.

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