A recirculating ball power steering machine spool, a screw assembly containing the spool, and a light hand steering machine

Abstract

The invention provides a recirculating ball power steering gear valve element, a screw rod assembly with the valve element and a light hand-power steering gear with the valve element. The shape of a cut of a valve element oil groove cutting edge is a spline curve composed of a plurality of points. A large-diameter penetrating structure screw rod is adopted for the screw rod assembly, and rotating limitation of the valve element and the screw rod is achieved through a limiting pin. Compared with the prior art, input hand power of a driver for a steering wheel is relieved through the light hand-power steering gear, frictional resistance is reduced, the manipulation is gentle and smooth, steering adhesion and blocking do not exist, and the road feel is clear. While the stability of linear driving is guaranteed, hydraulic assisting power can intervene rapidly within a common steering angle, and thus the manipulating force can be effectively relieved. The light hand-power steering gear has very good popularization and application value.

Description

technical field [0001] The invention relates to the technical field of steering gear production, in particular to a recirculating ball power steering gear spool, a screw assembly containing the spool, a light-hand power steering machine and a light-hand power steering gear. Background technique [0002] At present, the widely used recirculating ball hydraulic power steering machine is mainly composed of a shell, a recirculating ball screw nut assembly, and several large structural parts of the gear fan shaft. The control of the hydraulic power is mainly through the steering control valve integrated in the screw assembly. accomplish. Steering control valves are mainly in the form of slide valve and rotary valve. Among them, the slide valve type has been phased out due to its complex structure, and the rotary valve type has been widely used because of its compact structure and high control sensitivity. The structural size and geometric parameters of the related parts of the ...

AI Technical Summary

Problems solved by technology

In the prior art, the design and calculation of the geometric shape of the cutting edge is biased towards theoretical analysis. If the geometric shape of the cutting edge is complex, it is difficult for the conventional grinding process to guarantee the accuracy of the geometric shape. Therefore, the current basic method is to use an inverted corners or several arcs with different radii to form the geometry of the cutting edge, such as the shapes described in patents CN94202303. Obvious, and sudden changes in the process of building pressure that cause steering jerk

For the adjustment of torsion bar stiffness, the structure of existing products mostly adopts non-penetrating screw structure, as described in patent CN201320305563.2, or the rotary valve and screw are separated, as described in patent CN99224497.8, this type of structure Short overall length, making it difficult to reduce stiffness by increasing torsion bar length

It is only possible to reduce the hand force by reducing the diameter of the torsion bar. However, because the diameter of the torsion bar is too small, its strength and stability are also significantly reduced. Excessive reduction of the rod stiffness will affect the automatic return performance of the steering gear, causing the driver to feel that the direction is fluttering and pointing inaccurately when driving in a straight line.

In addition, most of the existing product structures meet the needs of the rotary valve rotation limit mechanism by processing lugs or tapered grooves on the end surface of the screw, as described in the patent CN200720087046. To achieve positioning and reduce friction to the bearing, the bearing bears a large axial force, and it is difficult to further reduce frictional resistance

Therefore, simply relying on reducing the diameter of the torsion bar to reduce the hand force of the steering machine cannot achieve significant results.

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