Electric power steering gear for automobile

Abstract

The invention discloses an electric power steering gear for an automobile. The steering gear comprises a motor power control module, a speed reducer and the steering gear. The motor power control module regulates and controls a worm and gear transmission speed reducing mechanism in the speed reducer, and the steering gear comprises a steering screw, a steering nut, a gear shaft, a torsion bar, a torque sensor and an input shaft; and the steering screw is in transmission connection with a worm wheel in the worm and gear transmission speed reduction mechanism, one end of the steering screw and the steering nut form a ball screw transmission pair assembly, a rack is arranged outside the steering nut and is in meshing transmission with one end of a gear shaft, the other end of the gear shaft is connected with an input shaft through the torsion bar, and a torque sensor is installed on the gear shaft. Compared with an existing recirculating ball type electric power steering gear, by using the steering gear of the invention, a steering pull rod force can be larger, and therefore the electric power steering gear is suitable for light, medium and heavy full-series automobile types; and compared with an existing gear and rack electric power steering gear, the electric power steering gear has the advantage that a more flexible whole automobile steering arrangement mode can be provided.

Description

Technical field[0001]The present invention belongs to the technical field of automotive parts, and more particularly to an electric power booster for automobiles.Background technique[0002]The current electric power steering is mainly a circulating ball electric power steering gear and gear rack electric power steering.[0003]The circulating spherical electric power steering force is flexible, but since the ratio of the gear index circular radius of the steering arm shaft is generally less than 1: 3, the circulating ball steering is output to the axial force on the steering tensile rod. At the same time, at the same time, at the same time, at the same time, due to the presence of the teeth pressure angle of the steering nut and the steering arm shaft, the screw of the steering force is received by a large radial force when transmitting large torque, the ancestation. Several reasons have led to a large amount of circulation steel balls inside the steering, and the steel ball rolling st...

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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