JPH0586753U - Telescopic steering shaft - Google Patents

Abstract

(57) [Summary] [Purpose] To provide at low cost a smooth axial movement of the upper shaft and the lower shaft of a telescopic steering column and a circumferentially rotatable structure without play (misalignment). [Structure] A steering shaft is composed of an upper shaft 1 and a lower shaft 5 which extendably engage with each other through axial grooves 3 and 4, and a axial groove 4 is provided on the outer peripheral surface. A disk 8 in which an elastic small diameter shaft portion 6 projecting in the axial direction is provided at the end portion of the lower shaft 5, and an axial groove 7 is formed on the outer peripheral surface at the end portion of the small diameter shaft portion 6.
After the disk 8 is inserted into the sleeve 2 first, the lower shaft 5 is slightly twisted to make the small diameter shaft portion 6
When the line groove 4 is inserted into the line groove 3 of the sleeve 2 by twisting to cause a pitch deviation, the play (misalignment) of the spline or serration engagement disappears and the operation feeling is improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a telescopic steering shaft in a vehicle steering system.

[0002]

[Prior Art]

 The steering shaft, which rotatably supports the steering wheel of an automobile and transmits rotational torque to the steering gear box, has an axially expandable structure, namely a telescopic steering shaft, to ensure the optimum driving posture of the occupant. However, this generally involves forming a male spline or serration shaft axially formed on the outer peripheral surface of one end and a female spline or serration shaft for fitting the spline on the inner peripheral surface of the one end. It consists of the upper shaft and the lower shaft.

Therefore, when adjusting the steering wheel to the optimum position for the occupant, the steering wheel is moved in the front-rear direction by a desired amount to extend and contract the upper shaft from the lower shaft, and rotatably fixedly held in that state. ..

However, when the upper shaft and the lower shaft are engaged by the spline or the serration with the material as it is, the clearance between the splines or the serrations is so large that a so-called rattling (mismatch) occurs, which adversely affects the operation feeling. There are drawbacks. If this clearance is too small, the expansion and contraction performance will decrease.

Therefore, a resin coating is applied to the male spline shaft to absorb the clearance between the splines within a range that does not affect the expansion / contraction performance, which results in smooth axial movement and looseness during rotation in the circumferential direction. I try not to occur.

[0006]

However, it is difficult to improve the machining accuracy of the spline or the serration engagement in order to make the spline or the serration engagement free of rattling, which causes a high cost, and is difficult. The processing work of applying the resin coating to the spline shaft requires the steps of applying and finishing the resin, resulting in an extremely high cost, and as a result, the cost of the steering column is increased.

In view of this, the present invention provides a telescopic steering shaft that can be expanded and contracted in the axial direction with a mechanical structure that does not cause backlash, instead of resin coating.

[0008]

[Means for Solving the Problems]

 The telescopic steering shaft according to the present invention constitutes a steering shaft with an upper shaft and a lower shaft that are elastically engaged with each other through a groove formed in the axial direction, and the axial groove is formed on the outer peripheral surface. An elastic small-diameter shaft portion projecting in the axial direction is provided at the end of one of the shafts, and a disk having axial grooves formed on the outer peripheral surface is fixed to the end of the small-diameter shaft portion. Is characterized by.

[0009]

[Action]

 According to this invention, when one shaft having a groove formed on the outer peripheral surface is inserted into the other shaft having a groove formed on the inner peripheral surface, the disc at the tip of one shaft is inserted into the other shaft. After inserting the shaft, if one shaft is slightly twisted and then inserted into the other shaft, the elastic small diameter shaft part is twisted, and the restoring force gives the other shaft a rotational force. To the groove of the other shaft to eliminate the clearance and eliminate the looseness of the groove engagement.

[0010]

【Example】

 The invention will be described below with reference to the illustrated embodiment. In FIG. 1, a sleeve 2 is connected to an end portion of an upper shaft 1, and a groove 3 made of spline or serration is formed on an inner peripheral surface of the sleeve 2. A lower shaft 5 having an outer peripheral surface formed with a groove 4 that engages with the groove 3 is inserted into the sleeve 2 so as to be movable in the axial direction.

The lower shaft 5 is connected with a small-diameter shaft portion 6 extending axially from the center of the end portion thereof by a predetermined length. A disc 8 having an axially formed groove 7 for engaging with the groove 3 is fixed to the outer peripheral surface of the small diameter shaft portion 6. The groove 7 is kept in phase contrast with the groove 4, or is formed in the same direction.

The small-diameter shaft portion 6 is made of, for example, a torsion bar having elasticity, and oval or prismatic modified cross-section portions 6a, 6a are formed at both ends thereof, and both end portions thereof are formed on the lower shaft 5 and the disk 8. The holes 5a and 8a that have been drilled are fitted and connected to each other. In this connection, in addition to the structure in which the cross-section is engaged in an irregular shape, as shown in FIG. 3, one end connects the lower shaft 5 and the small diameter shaft portion 6A with the pin 9, and the other end uses the serration 10. A structure may be used in which the disk 8A and the small diameter shaft portion 6A are connected.

Further, as shown in FIG. 4, the small-diameter shaft portion 6 is not connected to the lower shaft 5 as a separate body, but as shown in FIG. 4, it is cut by dividing the groove 4a formed at the end portion of the lower shaft 5a into two. The small diameter shaft portion 6A may be formed to form the disk 8A at the end, and the small diameter shaft portion 6A may be quenched so as to have elasticity.

Further, the small diameter shaft portion 6 is projected from the end portion of the lower shaft 5, but as shown in FIG. 3, a hole 11 is bored in the axial direction at the center of the end portion of the lower shaft 5 and One end of the small diameter shaft portion 6 is inserted into the hole 11 and fixed by a pin 9, and the serration 10 formed at the other end of the small diameter shaft portion 6 is projected from the lower shaft 5 and the disc 8 is attached to the serration 10. The structure may be such that they are engaged and fixed.

The operation of the above embodiment will now be described. When the steering shaft is constructed and the lower shaft 5 is inserted into the upper shaft 1, first, the groove 7 of the disk 8 is aligned with the groove 3 and the disk 8 is inserted. Is inserted into the upper shaft 1, and then the lower shaft 5 is twisted about its axis to insert the lower shaft 5 into the upper shaft 1 in a state where the groove 4 is in phase with the groove 3. When the groove 7 and the groove 4 are formed in the same phase, align the groove 7 with the groove 3 and insert the disk 8 into the upper shaft 1. Then, twist the lower shaft 5 about the axial center by one. The lower shaft 5 is inserted into the upper shaft 1 in a state that the groove 4 is coaxial with the groove 3 by giving a pitch. When the groove 7 and the groove 4 are formed in the same phase, the groove 7 is aligned with the lock groove 3, the disc 8 is inserted into the upper shaft 1, and then the lower shaft 5 is twisted about the axial center. The lower shaft 5 is inserted into the upper shaft 1 in a state where the groove 4 is in the same phase as the groove 3 by giving a pitch.

Therefore, since the small-diameter shaft portion 6 has elasticity, a rotational force about the shaft center is given to the disk 8 in the upper shaft 1, so that the groove 7 is formed in the groove 3 as shown in FIG. 5A. On the other hand, while the clearance 20 is biased to one side against the other side, the groove 4 on the small diameter shaft portion 6 is pressed against the groove 3 in the opposite direction, and as shown in FIG. Since 21 is put side by side, there is no backlash during operation. Since the torsional torque applied to the small diameter shaft portion 6 can be adjusted by adjusting the phase difference of the groove 7, the expansion / contraction performance is not hindered.

[0017]

[Effect of the device]

 According to the present invention described above, the steering shaft is composed of the upper shaft and the lower shaft which are extendably and contractably engaged with each other through the groove formed in the axial direction, and the groove formed in the axial direction is formed on the outer peripheral surface. An elastic small shaft portion projecting in the axial direction is provided at the end portion of one of the shafts, and a disc having an axial groove formed on the outer peripheral surface is fixed to the end portion of the small diameter shaft portion. In the other shaft, the disc is constantly given a rotational force by the elasticity of the small diameter shaft part, the groove of the disc is biased to the groove of the other shaft, and the clearance disappears. The looseness (mismatch) between the lower shaft and the lower shaft is eliminated, and the operation feeling is improved. Moreover, the process for forming the groove does not have to be highly precise, and since no resin coating is applied, it can be manufactured at extremely low cost.

[Brief description of drawings]

FIG. 1 is a sectional side view showing an embodiment of the present invention.

FIG. 2 is a partial perspective view of a part of FIG.

FIG. 3 is a sectional side view showing a main part of another embodiment.

FIG. 4 is a sectional side view showing a main part of another embodiment.

5 (a) and 5 (b) are explanatory views of operation, respectively.

[Explanation of symbols]

 1 ... Upper shaft 2 ... Sleeve 3,4,4a, 7 ... Slit groove 5 ... Lower shaft 6,6A ... Small diameter shaft part 8,8A ... Disc

Claims (1)

[Scope of utility model registration request] 1. A steering shaft is composed of an upper shaft and a lower shaft that extendably engage with each other via a groove formed in the axial direction, and one shaft having an axial groove on its outer peripheral surface. A telescopic · characterized in that an elastic small diameter shaft portion projecting in the axial direction is provided at the end portion, and a disk having an axial groove formed on the outer peripheral surface is fixed to the end portion of the small diameter shaft portion. Steering shaft.