Steering device for motor vehicle

Abstract

There is disclosed a steering apparatus for a vehicle in which a steering power of a steering shaft is assisted by a column-assist type electric power steering apparatus so that the steering power is transmitted to steer the wheels by means of a steering mechanism, in which a telescopic shaft with a male shaft and a female shaft fitted to each other to be mutually unrotatable and slidable is interposed between an output shaft of said column-assist type electric power steering apparatus and an input shaft of the steering mechanism.

Description

technical field [0001] The present invention relates to a steering device for a vehicle, wherein the steering force of the steering shaft is assisted by a column assist type electric steering device so that the steering force with increased torque is transmitted through a telescopic intermediate shaft so that when turning The wheels are steered by the steering mechanism. Background technique [0002] In Japanese Patent Application Laid-Open No. 1-145670, an intermediate shaft is interposed between the output shaft of the column-assisted electric steering device and the pinion shaft of the steering gear. A shock absorber for reducing the reaction force from the road surface is provided on the intermediate shaft. However, the intermediate shaft is not lengthened and / or shortened axially. [0003] Figure 9 to Figure 12 A steering device for a vehicle according to the prior art is shown. According to the prior art, an intermediate shaft that is collapsible in a secondary col...

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Problems solved by technology

[0034] In these structures, since the leaf springs with different curvatures are arranged in the grooves of the male or female shafts with curvature, it is difficult to obtain a large deflection amount of the leaf springs

Therefore, it is difficult to provide a leaf spring having an amount of deflection that can allow fluctuations in machining accuracy of the male and female shafts

[0035] When the torque is input, the male shaft, the leaf spring, the ball and the female shaft contact each other (crowd together) to transmit the torque, so that the point of contact with the ball has a very high surface pressure, and the steering shaft may not be able to meet the needs of the vehicle Torque transmission performance and life (especially when the steering shaft is combined with column assist electric power steering that needs to transmit high torque)

[0036] Since the external leaf spring tends to slip relative to the female shaft and is prone to lag when transmitting torque, there is a structural problem of not being able to control the magnitude of this lag

[0037] However, in the above-mentioned prior art, even considering Japanese Patent Application No. 1-145670, Fig. 9 to Figure 12 The prior art shown, the above-mentioned European Patent Application Publication No. EP1078843A1 and the above-mentioned German Patent No. DE3730393C2, do not provide telescoping shafts with properties that can be combined with column-assisted electric steering

Therefore, it is difficult to obtain a steering system with excellent performance satisfying the above items

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