A kind of electric power steering gear for automobile

Abstract

The invention discloses an electric power steering gear for automobiles, which includes a motor power control module, a reducer and a steering gear, the motor power control module regulates the worm gear transmission deceleration mechanism in the reducer, and the steering gear includes a steering screw, a steering nut, and a gear shaft , torsion bar, torque sensor and input shaft; the steering screw is connected with the worm gear in the worm gear reduction mechanism, one end of the steering screw and the steering nut form a ball screw transmission sub-assembly, and the outer part of the steering nut is provided with a rack, the rack It is engaged with one end of the gear shaft for transmission, and the other end of the gear shaft is connected with the input shaft through a torsion bar, and a torque sensor is installed on the gear shaft. The present invention can provide a larger steering rod force than the existing recirculating ball electric power steering device, so it is suitable for all models of light, medium and heavy vehicles; compared with the existing rack and pinion electric power steering device, the present invention can Provide a more flexible vehicle steering arrangement.

Description

technical field [0001] The invention belongs to the technical field of auto parts, and in particular relates to an electric power steering gear for automobiles. Background technique [0002] Current electric power steering mainly includes recirculating ball electric power steering and rack and pinion electric power steering. [0003] The layout of the recirculating ball electric power steering is flexible, but since the ratio of the radius of the gear index circle of the steering arm shaft to the center distance of the drop arm is usually less than 1:3, the axial force output from the recirculating ball steering to the steering rod It is less than 1 / 3 of the axial force of the steering nut. At the same time, due to the existence of the pressure angle of the tooth shape of the steering nut and the steering arm shaft, the screw of the steering gear is subjected to a large radial force when transmitting a large torque. Several reasons lead to the large force on the circulating...

AI Technical Summary

Problems solved by technology

[0003] The layout of the recirculating ball electric power steering is flexible, but since the ratio of the radius of the gear index circle of the steering arm shaft to the center distance of the drop arm is usually less than 1:3, the axial force output from the recirculating ball steering to the steering rod It is less than 1 / 3 of the axial force of the steering nut. At the same time, due to the existence of the pressure angle of the tooth shape of the steering nut and the steering arm shaft, the screw of the steering gear is subjected to a large radial force when transmitting a large torque. Several reasons lead to the large force on the circulating steel ball inside the steering gear, and the stress on the ball raceway, which will lead to early damage to the steering gear, so the steering force that can be provided to the steering rod system of the car is small, which is not suitable for heavy duty vehicle

[0004] Rack-and-pinion electric power steering is limited to the strength of the tie rod of the steering gear, and it is not suitable for heavy-duty vehicles

At the same time, due to the rack and pinion steering gear, the steering tie rod is directly connected to the rack, so it is difficult to apply to the model of the steering straight rod

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