JPH10259816A - Flexible shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible shaft which has large torsional rigidity and can transmit large torque without increasing the number of turns of wire. SOLUTION: In a flexible shaft 10, a spiral plate 14 is arranged spirally around a core wire 12. A left-hand wound wire 22A and a right-hand wound wire 22B are spirally wound around the spiral plate 14 such that they are crossing each other. When a large torsional force is applied to the flexible shaft 10, a fastening force in the radial direction of the left-hand wound wire 22A and the right-hand wound wire 22B is increased but is received by the spiral plate 14 to keep the radii of wind of the left-hand wound wire 22A and the right-hand wound wire 22B, whereby torque can be transferred reliably. The number of turns of the left-hand wound wire 22A and that of the right-hand wound wire 22B are not increased and hence the outer diameter of the flexible shaft 10 is not increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flexible shaft suitable for use as a steering shaft of a vehicle such as an automobile.

[0002]

2. Description of the Related Art There are various types of steering shafts for connecting a steering wheel for a vehicle such as an automobile to a steering gear box, and a steering device using a flexible shaft as a steering shaft has been proposed. (As an example, Japanese Utility Model Application Laid-Open No. 59-89768).

In the steering apparatus disclosed in the above publication, the steering shaft and the input shaft of the steering gear box are connected by a flexible shaft, and no conventional joint or the like for connecting the shaft is required. Is extremely simple, and the cost can be reduced.

However, on the other hand, in the steering device, the flexible shaft connected to the input shaft of the steering gear box is basically configured to operate the hydraulic control valve of the power steering device (power steering device). Therefore, this configuration is applicable only when it is not necessary to cope with a large transmission torque. In other words, the flexible shaft of the steering device may not be able to transmit a large torque due to insufficient torsional rigidity. And there was room for improvement in this regard.

[0005] In this case, by increasing the number of steel wires (the number of turns of the wire) constituting the flexible shaft,
A flexible shaft having a high torsional rigidity and capable of transmitting a large torque has been proposed (for example, Japanese Patent Application Laid-Open No. 3-177610).

However, if the torsional rigidity is increased simply by increasing the number of steel wires as in the flexible shaft disclosed in the above-mentioned publication, the shaft diameter of the flexible shaft itself becomes large, and for example, a steering shaft to which this is applied is used. The size of the device is increased.

[0007]

SUMMARY OF THE INVENTION In consideration of the above fact, the present invention has a high torsional rigidity and can transmit a large torque, and realizes this without increasing the number of turns of a wire. It is an object of the present invention to obtain a flexible shaft.

[0008]

According to a first aspect of the present invention, there is provided a flexible shaft spirally wound so as to intersect a flexible core wire and a predetermined outer diameter position around the core wire. A right and left winding and the left and right windings around the core wire are provided in a row at predetermined intervals along the axial direction, and a radial tightening force of the left and right windings caused by the tension of the left and right windings. And a space member for receiving the left and right windings to maintain the winding diameter of the left and right windings.

The flexible shaft according to the first aspect transmits the torque inputted from one end to the other end.
In this case, the load around the axis of the flexible shaft (radial tightening force of the left and right windings) is received by the space member,
The core wire receives the load in the axial direction.

Here, when a large torque (torsional force) acts on the flexible shaft, both ends of the flexible shaft try to approach each other, and the tensile stress of the left and right windings increases, so that the radial direction of the left and right windings increases. Increases the clamping force. However, the radial fastening force of the left and right windings is received by the space member, and the winding diameter of the left and right windings is maintained.

As described above, even if a large torque (torsional force) acts on the flexible shaft, the space members maintain the winding diameters of the left and right windings, so that the torsional rigidity of the flexible shaft decreases. And a large torque can be transmitted. Further, since the configuration is not such that the torsional rigidity is improved by increasing the number of turns of the left and right windings, the outer diameter of the flexible shaft does not increase.

Therefore, the flexible shaft according to claim 1 can be suitably used as a steering shaft of a steering device for a vehicle. In this case, the operating force of the steering wheel is reliably transmitted to the steering gear box via the flexible shaft, and the wheel can be steered by operating the steering wheel.

As described above, in the flexible shaft according to the first aspect, it is possible to transmit a large torque with high torsional rigidity, and to realize this without increasing the number of turns of the strand. it can.

The space member may be a spiral plate provided in the shape of a spiral around the core wire along the axial direction, or at predetermined intervals along the axial direction around the core wire. An arranged space disk can be used.

[0015]

FIG. 2 shows an overall configuration of a vehicle steering apparatus 30 in which a flexible shaft 10 according to a first embodiment of the present invention is applied as a steering shaft.

The steering device 30 includes a steering gear box 34 for turning a wheel 32.
One end of the flexible shaft 10 is connected to the steering gear box 34. The other end of the flexible shaft 10 is connected to a steering wheel 36. Thus, the operation force of the steering wheel 36 is transmitted via the flexible shaft 10 and the wheels 32 are steered.

FIG. 1 is a sectional view of a main part of the flexible shaft 10. The flexible shaft 10 has a core wire 12. Core wire 12
Has flexibility.

A spiral plate 14 is disposed around the core wire 12 as a space member. The spiral plate 14
It is made of a plate material, is spirally arranged around the core wire 12, and is provided in several lines. This spiral plate 14
It has flexibility.

Further, around the spiral plate 14, the left winding 2
2A and a right winding 22B are provided. Left winding 22A
The right winding 22B is spirally wound so as to cross each other. Note that, in this case, the left winding 22A positioned radially inward is wound in a spiral direction opposite to the direction of the spiral of the spiral plate 14, whereby the left winding 22A is wound around the spiral groove of the spiral plate 14. Is prevented from entering.

Next, the operation of the first embodiment will be described. In the steering device 30 to which the flexible shaft 10 having the above configuration is applied, the load around the axis of the flexible shaft 10 (radial tightening force of the left winding 22A and the right winding 22B) during normal operation of the steering wheel 36. Is received by the spiral plate 14, and the load in the axial direction is received by the core wire 12. Therefore, the steering wheel 36
Is operated, this operating force is applied to the left winding 22A and the right winding 2
The wheels 32 are transmitted to the steering gear box 34 via the 2B and the spiral plate 14, and the wheels 32 are steered.

Here, when a large torsional force acts on the flexible shaft 10 from the wheel 32 (for example, when the wheel 32 rides on a curb), both ends of the flexible shaft 10 tend to approach each other. Therefore, the tensile stress of the left winding 22A and the right winding 22B and the compressive stress of the core wire 12 increase, and the left winding 22A and the right winding 22
The tightening force in the radial direction of B increases. However, the radial tightening force of the left winding 22A and the right winding 22B is
The winding diameter of the left winding 22A and the right winding 22B is maintained by being received by the spiral plate 14.

As described above, even if a large torque (torsional force) acts on the flexible shaft 10, the spiral plate 14 maintains the winding diameters of the left winding 22A and the right winding 22B. Large torque can be transmitted without lowering the torsional rigidity. In addition, since the number of turns of the left winding 22A and the right winding 22B is not increased or the outer diameter of the shaft is increased to improve the torsional rigidity, the outer diameter of the flexible shaft 10 does not increase.

As described above, in the flexible shaft 10 according to the present embodiment, it is possible to transmit a large torque with high torsional rigidity, and to realize this without increasing the number of turns of the strand. Can be.

Next, FIG. 3 is a sectional view of a main part of a flexible shaft 40 according to a second embodiment of the present invention.

In the flexible shaft 40, the space disk 4 as a space member is provided around the core wire 12.
2 are arranged. The space disks 42 are arranged in rows around the core wire 12 at predetermined intervals along the axial direction. A left winding 22A and a right winding 22B are spirally wound around the space disk 42 so as to cross each other.

Also in the flexible shaft 40 having the above-described structure, the space disk 42 receives the load around the axis of the flexible shaft 40 (the radial tightening force of the left winding 22A and the right winding 22B), and the axial load. Is received by the core wire 12. Therefore, when the steering wheel 36 is operated, this operating force is transmitted to the steering gear box 34 via the left winding 22A, the right winding 22B and the space disk 42, and the wheels 32 are steered.

When a large torsional force acts on the flexible shaft 40, the flexible shaft 4
The two ends of 0 try to approach each other. Therefore, the tensile stress of the left winding 22A and the right winding 22B and the compressive stress of the core wire 12 increase, and the tightening force in the radial direction of the left winding 22A and the right winding 22B increases. However, the left winding 22
The radial clamping force of A and the right winding 22B is received by the space disk 42, and the winding diameter of the left winding 22A and the right winding 22B is maintained.

As described above, even if a large torque (torsion force) is applied to the flexible shaft 40, the winding diameter of the left winding 22A and the right winding 22B is maintained by the space disk 42, so that the flexible shaft 40 Large torque can be transmitted without lowering the torsional rigidity. Further, since the configuration is not such that the number of turns of the left winding 22A and the right winding 22B is increased or the outer diameter of the shaft is increased to improve the torsional rigidity, the flexible shaft 4
The outer diameter of 0 does not increase.

As described above, in the flexible shaft 40 according to the second embodiment, the torsional rigidity is high and a large torque can be transmitted, and this can be performed without increasing the number of turns of the strand. Can be realized.

In the flexible shaft 40 according to the second embodiment, the space disks 42 arranged in a row may be filled with a resin material such as rubber or urethane. In this case, it is possible to prevent the space disk 42 from inclining (falling) with respect to the core wire 12, which is more effective.

[0031]

As described above, the flexible shaft according to the present invention has a high torsional rigidity and can transmit a large torque, and can realize this without increasing the number of turns of the strand. It has an excellent effect of being able to perform

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a flexible shaft according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an entire configuration of a steering device to which the flexible shaft according to the embodiment of the present invention is applied.

FIG. 3 is a sectional view of a main part of a flexible shaft according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flexible shaft 12 Core wire 14 Spiral plate (space member) 22A Left winding 22B Right winding 30 Steering device 32 Wheel 34 Steering gear box 36 Steering wheel 40 Flexible shaft 42 Space disk (Space member)

(72) Inventor Masahiko Asano 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (1)

[Claims] 1. A flexible core wire, left and right windings spirally wound so as to cross each other at predetermined outer diameter positions around the core wire, and the left and right windings around the core wire. A space member that is provided in a row at a predetermined interval along the axial direction and receives the radial tightening force of the left and right windings caused by the tension of the left and right windings and maintains the winding diameter of the left and right windings. And a flexible shaft comprising: