Thrust bearing for screw of ball-nut type steering gear

Abstract

The invention provides a thrust bearing for the screw of a ball-nut type steering gear. The thrust bearing comprises a screw. A thrust ball type thrust bearing is arranged on screw. The thrust ball type thrust bearing comprises a steel ball and a ring. The ring is composed of a left semi-ring and a right semi-ring. The cross section of the thrust ball type thrust bearing raceway is a four point contact type. The left semi-ring and the right semi-ring are both provided with a corresponding arc outer raceway. Two arc inner raceways are arranged on the screw. The radius of two inner raceways is the same as that of two outer raceways. The centers of four arc raceways are in a same circumference, but four arc raceways are non-concentric. The steel ball is arranged between the screw and the ring. Four contact points are formed between the steel ball and two outer raceways and two inner raceways, and thus a four point contact type thrust ball bearing is formed. In assembly, a punching-riveting anti-loosening structure is adopted between an adjusting nut and a valve body. For the bearing, a screw is used to replace a shaft washer, a holder is not needed any more, and the installation becomes convenient. The inner raceway and outer raceway are both composed of two arcs, a four point contact ball bearing is formed and is capable of bearing a large axial / radial force, the wear is reduced, and the service life is prolonged.

Description

technical field [0001] The invention relates to the technical field of automobile steering gear manufacturing, in particular to a thrust bearing used on a screw rod of a recirculating ball steering gear. Background technique [0002] At present, there are two types of thrust bearings used on the screw rod of automobile recirculating ball steering gear: one is needle roller thrust bearing, such as figure 1 As shown, it is generally used for the steering gear of the through-type screw. When in use, it only bears the axial force of the screw 1, and does not limit the radial direction of the screw 1. When assembling, it is installed and adjusted at the tail (or head) of the screw 1. screw (or adjusting screw) to adjust the axial clearance of the screw rod 1. Due to the radial jump of the valve sleeve of the screw rod during the rotation of the screw rod, the radial runout of the bearing of this structure will cause great wear and tear of the three oil seals here, and the service...

AI Technical Summary

Problems solved by technology

[0002] At present, there are two types of thrust bearings used on the screw rod of automobile recirculating ball steering gear: one is needle roller thrust bearing, such as figure 1 As shown, it is generally used for the steering gear of the through-type screw. When in use, it only bears the axial force of the screw 1, and does not limit the radial direction of the screw 1. When assembling, it is installed and adjusted at the tail (or head) of the screw 1. screw (or adjusting screw) to adjust the axial clearance of the screw rod 1. Due to the radial jump of the valve sleeve of the screw rod during the rotation of the screw rod, the radial runout of the bearing of this structure will cause great wear and tear of the three oil seals here, and the service life is short. Finally, internal leakage causes heavy steering; the other is thrust ball bearings, such as figure 2 As shown, it is generally used for the diverter of the non-through screw. When in use, it mainly positions the screw 2 of the diverter axially and bears the axial force of the screw 2 (this force is relatively large). It can perform radial positioning and bear the radial force of the screw 2 (this force is relatively small), and adjust the axial clearance of the screw 2 by installing the adjusting nut 3 at the tail end of the screw 2 during assembly, and by adding a locking ring 4 Anti-loosening treatment is carried out on the adjusting nut 3, so as to indirectly reduce the radial runout of the screw 2 at the valve sleeve, reduce the wear of the three oil seals here, and prolong the life of the oil seal

Commonly used thrust ball bearings are mostly in contact with a single arc surface, with high friction and easy wear, resulting in a large axial clearance in the steering gear. At the same time, thrust ball bearings are mostly pressed into the bearing hole by interference or transition fit , so that the radial clearance of the bearing is very small, when the radial clearance of other parts of the steering gear is also small (in order to ensure a small free clearance of the steering gear, the clearance of the threaded raceway motion pair and the gear pair motion pair are usually reduced as much as possible Clearance), it is easy to cause the radial jump of the valve sleeve of the screw when the screw rotates (due to the misalignment between the rack piston, the shell, and the valve body), resulting in motion interference, and finally the return torque and input torque of the steering gear increase, affecting the steering performance of the car

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