JPH0714102Y2 - Steering shaft coupling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a vehicle steering shaft coupling structure.

[Prior Art] Generally, a steering shaft in a steering apparatus for a vehicle includes an upper shaft formed of a rod having a steering wheel axially attached to an upper end thereof and a lower shaft formed of a tube into which the upper shaft is axially fitted. An intermediate shaft is connected to the lower shaft via a universal joint, and the intermediate shaft is connected to the steering gear box. It is composed of two parts, the upper shaft and the lower shaft, in order to reduce or mitigate the impact of the secondary collision of the occupant in a vehicle collision accident as much as possible. It is well known that this is because the column adopts a structure that contracts in the axial direction when a load is input in the axial direction. Therefore, the upper shaft and the lower shaft are slidably coupled in the axial direction, and a clearance allowing the sliding is formed between the both.
If there is a clearance, there is a problem that abnormal noise is apt to occur due to vibration when the vehicle is running or idling, and that an occupant feels discomfort during steering.

Therefore, in order to prevent abnormal noise and rattling of the steering shaft, a conventional example of the connecting structure of the upper shaft and the lower shaft will be described with reference to FIGS. 7 and 8, and FIGS. ), (C), a polygonal shaft portion 2 processed into a so-called oval cross section is formed at one end of the upper shaft 1, and a lower shaft 3 into which the polygonal shaft portion 2 is inserted has a polygonal hole with an oval cross section. 4 are formed. Shallow peripheral grooves 5 and 5 are formed at appropriate intervals on the polygonal shaft portion 2 of the upper shaft 1, and the peripheral grooves 5 and 5 have the same thickness as the depth of the peripheral grooves 5 and 5, respectively. Clips 6,6 formed by bending an elastic plate into a U-shape are embedded, and the clearance 7 formed between the upper shaft 1 and the lower shaft 3 is eliminated by the spring force of the clips 6,6. In addition, in FIGS. 8 (A), (B), and (C),
In the upper shaft 1 and the lower shaft 3 having the same structure as described above, a spring 9 made of an elastic plate elongated in the axial direction is provided on one of the flat surfaces 8 of the polygonal shaft portion 2 of the upper shaft 1. One end is fixed to the flat surface 8 of the upper shaft 1 by caulking connection 9a, and the spring 9 is interposed in the clearance 7 so that the upper shaft 1 is biased to one side of the lower shaft 3.

[Problems to be Solved by the Invention] However, according to the conventional steering shaft coupling structure described above, in the structure shown in FIG. 7, the peripheral grooves 5, 5 must be cut on the upper shaft 1, The cutting process is also the process of cutting the flat surface 8,8 and the arc surface 8a, 8a
Since two types of steps for cutting are required, the work is troublesome and the cost is high. Also, the eighth
In the one shown in the figure, the peripheral grooves 5, 5 are not machined in the upper shaft 1, but the spring 9 is interposed in the clearance 7, so a large torque is applied to the upper shaft 1 during steering operation such as stationary steering. Is input, the spring 9 is compressed and deformed into a completely flat shape, so that the stress of the spring 9 becomes excessive and there is a problem in durability.
Further, the so-called play amount is a as shown in FIG. 8 (C).
Since it becomes − (c + t), it is affected by the processing accuracy of the three parts a, c, and t, so there is a tendency that the amount of backlash inevitably becomes large, and there is the drawback of poor steering stability.

Therefore, the present invention was made for the purpose of improving the steering shaft.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a steering shaft in which at least two shafts are axially slidably fitted through a hole and a shaft having a polygonal cross section. A groove having a width smaller than the width of the flat surface of the hole in the axial direction is formed in the hole, and the groove is formed of a corrugated elastic body having a thickness smaller than the groove depth, and at least one end Insert and lock the wave leaf spring with the hook formed,
A steering shaft connecting structure is formed by being pressed against the shaft.

[Operation] According to the present invention having the above-mentioned configuration, the wave leaf spring presses the shaft of the polygonal shaft portion against the inner surface of the polygonal hole of the other shaft to eliminate the clearance formed between the two, so that there is no play. It is possible to prevent abnormal noise from being generated from the steering shaft while the vehicle is traveling or idling, and to prevent discomfort caused by backlash in the twisting direction during steering.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. First
Figure is an exploded perspective view, Figure 2 is a vertical plan view, and Figure 3 is Figure 2.
It is a III-III sectional view taken on the line. In the figure, the same parts as those in FIGS. 7 and 8 are designated by the same reference numerals.

The upper shaft 1 is formed with a polygonal shaft portion 2 having an oval cross section, and the lower shaft 3 is formed with a polygonal hole 4 into which the polygonal shaft portion 2 is fitted. The flat surfaces 4a, 4a of the polygonal hole 4 have grooves 10, 10 facing the flat surfaces 8, 8 of the upper shaft 1, respectively.
Is formed in a predetermined length in the axial direction, and a wave leaf spring 11 of a predetermined length formed in a corrugated shape with a wall thickness smaller than the depth of the groove 10 is inserted into either or both of the grooves 10, 10. ing. The grooves 10, 10 are flat surfaces 12, 12 of the lower shaft 3.
The protrusions 13, 13 are formed by molding, and the width W _{1 of the} grooves 10, 10 is smaller than the width W of the flat surfaces 4a, 4a of the polygonal hole 4. The wave leaf spring 11 has a hook portion 14 at one end and is engaged with the end portion of the lower shaft 3 to connect the upper shaft 1 to the lower shaft 3.
When it is inserted into the lower shaft 3, the lower shaft 3 is held so as not to fall, and the upper shaft 1 is inserted so that the flat surface 8 of the upper shaft 1 can be pressed against the lower shaft 3. This wave leaf spring 11 is the lower shaft 3
The configuration shown in FIG. 4 to FIG. 6 may be adopted so as not to fall off from it. That is, the protrusion 1 of the lower shaft 3
The protrusion 13 in both or either
A through hole 15 is formed at the end of the
Hook portions 14 and 14 are formed at both ends of a. While fitting the hook portion 14 at one end of the wave leaf spring 11a into the through hole 15,
The hook portion 14 at the other end is locked to the end portion of the lower shaft 3. Therefore, the lower shaft 3 has a wave leaf spring 11
When a is attached, the wave leaf spring 11a does not fall off when the upper shaft 1 is inserted into the lower shaft 3 or when the upper shaft 1 slides in the direction of coming out of the lower shaft 3.

Explaining the operation of the above embodiment, the wave leaf spring
11 and 11a are respectively interposed between the upper shaft 1 and the lower shaft 3 and press the lower shaft 3 against the inner surface of the upper shaft 1, so that the clearance 7 therebetween is removed. However, since the wave leaf springs 11 and 11a are each made of a corrugated elastic body, they do not elastically contact the upper shaft 1 and prevent the upper shaft 1 from moving in the axial direction. Also, in steering operation such as stationary steering, if an excessive torque is input to the steering shaft, the flat surface 8,8 of the upper shaft 1
And the flat surfaces 4a, 4a of the polygonal hole 4 of the lower shaft 3 are pressed against each other by metal contacts, and the wave leaf springs 11 and 11a are housed in the groove 10 and are not subjected to pressure. Therefore, there is no inconvenience that the wave leaf springs 11 and 11a are deformed into a flat shape.

[Advantages of the Invention] According to the invention described above, in a steering shaft in which at least two shafts are axially slidably fitted through a shaft having a polygonal cross-section and a hole, A groove having a width smaller than the width of the flat surface of the hole is formed in the axial direction, and the groove is made of a corrugated elastic body having a wall thickness smaller than the groove depth, and a hook portion is formed at least at one end thereof. Since the steering shaft has a connecting structure in which a wave leaf spring is inserted and locked and brought into pressure contact with the shaft, it is inexpensive to form a groove in the lower shaft in which the wave leaf spring can intervene, so the cost is low. In addition to this, when inputting an excessive torque, both shafts transmit torque by the metal contact of the polygonal shaft part and the polygonal hole, and the wave leaf spring is accommodated in the groove and receives a force enough to deform it. Since it does not exist, durability is improved. Furthermore, since the amount of play between the shafts is determined by the dimensional accuracy of the polygonal shaft portion, it can be kept small by increasing the processing accuracy of the polygonal shaft portion. In addition, since the wave leaf spring has a hook portion and is locked to the end portion of one shaft, it is possible to confirm whether or not the wave leaf spring is attached from the outside, and product inspection can be performed.
And so on.

[Brief description of drawings]

1 is an exploded perspective view, FIG. 2 is a vertical sectional plan view, FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a vertical sectional plan view showing another embodiment, FIGS. The figure is a partial perspective view, FIGS. 7 and 8 show a conventional example, and FIG. 7 (A) is an exploded perspective view.
8B and 8C are cross-sectional views of the shaft, FIG. 8A is an exploded perspective view, FIG. 8B is a vertical plan view of the shaft, and FIG. 8C is a cross-sectional view. 2 ... Polygonal shaft part, 4 ... Polygonal hole, 4a, 12 ... Flat surface, 7
...... Clearance, 10 ... groove, 11,11a ... Wave leaf spring, 14 ... Hook part.

Claims (1)

[Scope of utility model registration request] 1. A steering shaft comprising at least two shafts axially slidably fitted to a shaft having a polygonal cross section through a hole, wherein the hole has an axial direction.
Also, a wave leaf spring is formed in which a groove having a width smaller than the width of the flat surface of the hole is formed, and the groove is made of an elastic body formed in a corrugated shape with a thickness smaller than the groove depth, and a hook portion is formed at least at one end. A steering shaft coupling structure characterized by being inserted, locked, and pressed against the shaft.