Worm and gear transmission mechanism

Abstract

One end of a worm is connected with a motor, the other end of the worm is meshed with a worm gear, the worm gear is provided with a through hole for an output shaft to penetrate through, a protection ring is arranged between the worm gear and the output shaft, and in the initial state, the inner circumferential wall of the protection ring is in interference fit with the outer circumferential wall of the output shaft. The outer circumferential wall of the protection ring is in interference fit with the inner circumferential wall of the through hole in the worm gear, the protection ring is made of elastic steel, and when the torque transmitted by the output shaft and the worm gear through the protection ring is larger than a preset torque threshold value, the output shaft rotates relative to the worm gear. Feedback force of the road surface is transmitted to the output shaft through cooperation of the sector gear shaft on the wheels, and the output shaft transmits torque to the worm gear through the protection ring. When the torque transmitted between the output shaft and the worm gear is larger than the preset torque threshold value, the output shaft can overcome the friction force between the output shaft and the torque limiting ring to rotate relative to the worm gear, and therefore it is guaranteed that the overload torque larger than the preset torque threshold value cannot damage the worm gear, and the worm gear is protected.

Description

TECHNICAL FIELD

[0001] The utility model relates to mechanical drive technical field, concretely relates to worm gear drive mechanism. BACKGROUND

[0002] In the steering assist drive mechanism with worm gear drive, the worm bears the driving force of the rotating drive mechanism to rotate, thereby driving the worm gear to rotate, the worm gear is rigidly connected with the output shaft, and the output shaft can drive the fan gear shaft to rotate for steering assist when the worm gear rotates with the worm, the driving torque borne by the worm gear is relatively stable. When the worm gear bears the feedback force from the road surface, the size of the feedback force is mainly affected by the road surface environment, especially when the automobile runs on the road surface with relatively severe bumping, the feedback force from the road surface is particularly severe, and the worm gear is damaged due to the inability of the worm gear and the output shaft to rotate relatively, thereby causing the failure of the steering assist drive structure and even the jamming, which seriously affects the reliability and safety of the automobile. SUMMARY

[0003] In view of the technical problem that the worm gear is damaged due to the inability of the worm gear and the output shaft to rotate relatively, the utility model provides a worm gear drive mechanism, when the torque transmitted between the output shaft and the worm gear is greater than a preset torque threshold, the output shaft can overcome the friction between the output shaft and the torque limiting ring to rotate relative to the worm gear, thereby ensuring that the overload torque greater than the preset torque threshold will not damage the worm gear.

[0004] The technical scheme adopted by the utility model is as follows: a worm gear drive mechanism, comprising a worm gear, a worm, an output shaft and a motor, one end of the worm is connected with the motor, the other end of the worm is engaged with the worm gear, the worm gear is provided with a through hole for the output shaft to pass through, a protective ring is arranged between the worm gear and the output shaft, in the initial state, the inner peripheral wall of the protective ring is in interference fit with the outer peripheral wall of the output shaft, and the outer peripheral wall of the protective ring is in interference fit with the inner peripheral wall of the upper through hole of the worm gear, the material of the protective ring is elastic steel, when the torque transmitted between the output shaft and the worm gear through the protective ring is greater than a preset torque threshold, the output shaft rotates relative to the worm gear.

[0005] Optionally, the protective ring is provided with a first opening, and a plurality of convex strips are arranged on the outer peripheral wall of the protective ring in a circumferential direction.

[0006] Optionally, the output shaft is connected with an input shaft, the input shaft is provided with a torque sensor, and the torque sensor is connected with a controller integrated in the motor.

[0007] Optionally, the utility model further comprises a shell, the shell comprises a first shell and a second shell integrally connected with the first shell, the first shell has a first cavity for accommodating the worm, the second shell has a second cavity for accommodating the worm gear and the output shaft, and the first cavity and the second cavity are communicated.

[0008] Optionally, one end of the worm is connected with the motor, and the other end of the worm is provided with an adjusting assembly, the adjusting assembly comprises a first adjusting piece, a bearing, a second adjusting piece, a spring ring and a flexible pad, the inner circumferential wall of the flexible pad is in contact with the outer circumferential wall of the worm, the outer circumferential wall of the flexible pad is in contact with the inner circumferential wall of the bearing, the inner circumferential wall of the first adjusting piece is in contact with the outer circumferential wall of the bearing, one side of the outer circumferential wall of the first adjusting piece is abutted against the inner wall of the first shell, the end surface of the first adjusting piece is provided with an arc-shaped plate with a second opening on one side, the spring ring is sleeved on the outer circumferential wall of the arc-shaped plate, one end of the second adjusting piece is movably located in the arc-shaped plate, and the other end of the second adjusting piece is abutted against the spring ring; the second opening of the arc-shaped plate is located on the side of the arc-shaped plate away from the worm.

[0009] Optionally, a plurality of notches are arranged on the outer circumferential wall of the arc-shaped plate.

[0010] Optionally, the second adjusting piece comprises a body and a limiting plate, one end of the body is movably located in the arc-shaped plate, and the other end of the body is abutted against the spring ring; the limiting plate extends along the radial direction of the body.

[0011] The utility model discloses the beneficial effect is: in the wheel feedback force of road surface is transmitted to the output shaft through the cooperation of fan tooth shaft, and the output shaft transmits the torque to the worm wheel through the protection ring. When the torque transmitted between the output shaft and the worm wheel is greater than the preset torque threshold, the output shaft can overcome the friction between it and the torque limiting ring and rotate relative to the worm wheel, thereby ensuring that the overload torque greater than the preset torque threshold will not damage the worm wheel, and further realizing the protection of the worm wheel. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The structure diagram of the worm gear transmission mechanism is provided for the embodiment of the utility model;

[0013] Figure 2 The schematic diagram of the protection ring is provided for the embodiment of the utility model;

[0014] Figure 3 The sectional view of the worm gear transmission mechanism is provided for the embodiment of the utility model;

[0015] Figure 4 The schematic diagram of the adjusting assembly is provided for the embodiment of the utility model.

[0016] The marks in each drawing are as follows: 1, worm wheel; 2, worm; 3, output shaft; 4, motor; 5, protection ring; 51, first opening; 52, convex strip; 6, input shaft; 7, torque sensor; 8, shell; 81, first shell; 83, second shell; 9, adjusting assembly; 91, first adjusting piece; 92, second adjusting piece; 921, body; 922, limiting plate; 93, spring ring; 94, arc-shaped plate; 95, notch; 96, flexible pad; 97, bearing. DETAILED DESCRIPTION

[0017] The application will be further described in detail below with reference to the accompanying drawings and examples.

[0018] As shown in the drawings, Figures 1 to 4 The embodiment discloses a worm gear transmission mechanism, which comprises a worm wheel 1, a worm 2, an output shaft 3 and a motor 4. One end of the worm 2 is connected with the motor 4, and the other end of the worm 2 is engaged with the worm wheel 1. The worm wheel 1 is provided with a through hole through which the output shaft 3 passes. A protective ring 5 is arranged between the worm wheel 1 and the output shaft 3. In the initial state, the inner circumferential wall of the protective ring 5 is in interference fit with the outer circumferential wall of the output shaft 3, and the outer circumferential wall of the protective ring 5 is in interference fit with the inner circumferential wall of the upper through hole of the worm wheel 1. The material of the protective ring 5 is elastic steel. When the torque transmitted between the output shaft 3 and the worm wheel 1 through the protective ring 5 is greater than a preset torque threshold, the output shaft 3 rotates relative to the worm wheel 1. The feedback force of the road surface is transmitted to the output shaft 3 through the cooperation of the fan tooth shaft, and the output shaft 3 transmits torque to the worm wheel 1 through the protective ring 5. When the torque transmitted between the output shaft 3 and the worm wheel 1 is greater than the preset torque threshold, the output shaft 3 can overcome the friction between the output shaft 3 and the torque limiting ring and rotate relative to the worm wheel 1, so as to ensure that the overload torque greater than the preset torque threshold will not damage the worm wheel 1, thereby achieving protection of the worm wheel 1.

[0019] In the embodiment, as shown in the drawings, Figure 2 The protective ring 5 is provided with a first opening 51, and the outer circumferential wall of the protective ring 5 is provided with a plurality of convex strips 52 arranged at intervals in the circumferential direction. The first opening 51 is beneficial to the installation of the protective ring 5 on the output shaft 3, and the reinforcing ribs can enhance the strength of the protective ring 5.

[0020] As shown in the drawings, Figure 1 The output shaft 3 is connected with an input shaft 6, the input shaft 6 is provided with a torque sensor 7, and the torque sensor 7 is connected with a controller integrated in the motor 4. The shell 8 comprises a first shell 81 and a second shell 83 integrally connected with the first shell 81. The first shell 81 has a first cavity for accommodating the worm 2, and the second shell 83 has a second cavity for accommodating the worm wheel 1 and the output shaft 3. The first cavity and the second cavity are in communication.

[0021] In the embodiment, as shown in the drawings, Figure 3 and 4As shown, one end of the worm 2 is connected with the motor 4, and the other end of the worm 2 is provided with an adjusting assembly 9, which comprises a first adjusting member 91, a bearing 97, a second adjusting member 92, a spring ring 93 and a flexible pad 96. The inner circumferential wall of the flexible pad 96 is in contact with the outer circumferential wall of the worm 2, the outer circumferential wall of the flexible pad 96 is in contact with the inner circumferential wall of the bearing 97, and the inner circumferential wall of the first adjusting member 91 is in contact with the outer circumferential wall of the bearing 97. The flexible pad 96 can be made of elastic materials such as rubber and silica gel, which provides elastic allowance for gap compensation. The inner circumferential wall of the first adjusting member 91 is sleeved on the outer circumferential wall of the outer ring of the bearing 97, one side of the outer circumferential wall of the first adjusting member 91 is abutted against the inner wall of the first shell 81, the end face of the first adjusting member 91 is provided with an arc-shaped plate 94 with a second opening on one side, the spring ring 93 is sleeved on the outer circumferential wall of the arc-shaped plate 94, one end of the second adjusting member 92 is located in the arc-shaped plate 94, and the other end of the second adjusting member 92 is abutted against the spring ring 93. The second opening of the arc-shaped plate 94 is located on the side of the arc-shaped plate 94 away from the worm wheel 1. The spring ring 93 is wound on the outer circumferential wall of the first adjusting member 91, and always provides a pre-tightening force to the second adjusting member 92, so that the second adjusting member 92 is always pressed towards the side of the arc-shaped plate 94 close to the worm wheel 1 in the radial direction, and then the arc-shaped plate 94 drives the first adjusting member 91 shell 8 to generate a radial force on the worm 2, so that the worm 2 is always in close contact with the worm wheel 1, the gap between the worm 2 and the worm wheel 1 is eliminated, and then the abnormal noise generated by the vehicle when reversing or passing through a bumpy road is eliminated. Here, the radial direction refers to the direction perpendicular to the axial direction of the worm 2.

[0022] As shown in the drawings, Figure 4 As shown, the outer circumferential wall of the arc-shaped plate 94 is provided with a plurality of notches 95. The notches 95 do not penetrate to the inner wall of the arc-shaped plate 94, and the provision of the notches 95 provides the spring ring 93 with more tightening space. The second adjusting member 92 comprises a body 921 and a limiting plate 922, one end of the body 921 is located in the arc-shaped plate 94, the other end of the body 921 is abutted against the spring ring 93, and the limiting plate 922 extends radially along the body 921. The limiting plate 922 is located at the end of the body 921 away from the first adjusting member 91, and the spring ring 93 is clamped between the limiting plate 922 and the first adjusting member 91, which can prevent the spring ring 93 from being axially displaced.

[0023] It can be understood that the specific embodiments described above are only used to explain the related utility model, and are not limited to the utility model. In addition, it should be noted that only the parts related to the utility model are shown in the drawings for convenience of description. The multiple technical solutions in the same embodiment and the multiple technical solutions of different embodiments can be arranged and combined to form new technical solutions without contradiction or conflict. Any equivalent structural transformation, direct or indirect application in other related technical fields, is also included in the protection scope of the utility model.

Claims

1. A worm and gear transmission mechanism, characterized by, The worm gear, the worm, the output shaft and the motor are included, one end of the worm is connected with the motor, the other end of the worm is engaged with the worm gear, the worm gear is provided with a through hole for the output shaft to pass through, a protective ring is arranged between the worm gear and the output shaft, in the initial state, the inner circumferential wall of the protective ring is in interference fit with the outer circumferential wall of the output shaft, the outer circumferential wall of the protective ring is in interference fit with the inner circumferential wall of the upper through hole of the worm gear, the material of the protective ring is elastic steel, when the torque transmitted by the output shaft and the worm gear through the protective ring is greater than a preset torque threshold, the output shaft rotates relative to the worm gear.

2. The worm and gear transmission mechanism according to claim 1, characterized in that, The protective ring is provided with a first opening, and the outer circumferential wall of the protective ring is provided with a plurality of convex strips in the circumferential direction.

3. The worm and gear transmission mechanism according to claim 1, characterized in that, The output shaft is connected with an input shaft, the input shaft is provided with a torque sensor, and the torque sensor is connected with a controller integrated in the motor.

4. The worm and gear transmission mechanism according to claim 1, characterized in that, Further comprising a shell, the shell comprises a first shell and a second shell integrally connected with the first shell, the first shell has a first cavity accommodating the worm, and the second shell has a second cavity accommodating the worm gear and the output shaft, and the first cavity and the second cavity are communicated.

5. The worm and gear drive according to claim 4, characterized in that One end of the worm is connected with the motor, and the other end of the worm is provided with an adjusting assembly, the adjusting assembly comprises a first adjusting piece, a bearing, a second adjusting piece, a spring ring and a flexible pad, the inner circumferential wall of the flexible pad is in contact with the outer circumferential wall of the worm, the outer circumferential wall of the flexible pad is in contact with the inner circumferential wall of the bearing, the inner circumferential wall of the first adjusting piece is in contact with the outer circumferential wall of the bearing, one side of the outer circumferential wall of the first adjusting piece abuts against the inner wall of the first shell, the end face of the first adjusting piece is provided with an arc-shaped plate with a second opening on one side, the spring ring is sleeved on the outer circumferential wall of the arc-shaped plate, one end of the second adjusting piece moves in the arc-shaped plate, and the other end of the second adjusting piece abuts against the spring ring, and the second opening of the arc-shaped plate is located on the side of the arc-shaped plate away from the worm gear.

6. The worm and wheel drive according to claim 5, characterized in that The outer circumferential wall of the arc-shaped plate is provided with a plurality of notches.

7. The worm and gear drive of claim 5 wherein, The second adjusting piece comprises a body and a limiting plate, one end of the body moves in the arc-shaped plate, the other end of the body abuts against the spring ring, and the limiting plate extends in the radial direction of the body.

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