JP2007015412A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device capable of simply reducing the relative rotational resistance of an input shaft and an output shaft. <P>SOLUTION: The steering device is equipped with the input shaft 1 having a bar inserting hole 1a, a torsion bar 2 with one end fixed to the hole 1a, and the output shaft 3 coupled with the other end of the torsion bar 2 and having a fit-in hole 3a in which the other end of the input shaft 1 is fitted, wherein a film layer 9 of fluoro-resin to decrease the relative rotational resistance of the input shaft 1 and output shaft 3 is provided on either of the fit-in hole 3a and the fit-in part 1b of the input shaft 1 into the fit-in hole 3a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steering apparatus including an input shaft and an output shaft connected by a torsion bar.

As a steering device, there are known a steering device including a hydraulic control valve for supplying and discharging pressure oil supplied to a steering assist hydraulic cylinder, and a steering device including a steering assist electric motor. In any steering device, an input shaft having a bar insertion hole, a torsion bar having one end fixed to the bar insertion hole, the other end of the torsion bar, and the other end of the input shaft are fitted. An output shaft having a fitting hole and a fitting cylinder fitted between the fitting hole and the fitting portion of the input shaft into the fitting hole (see, for example, FIG. 5 of Patent Document 1).
Japanese Utility Model Publication No. 6-37063

  By the way, the fitting cylinder of patent document 1 reduces the relative rotational resistance of an input shaft and an output shaft by suppressing the inclination with respect to the output shaft of an input shaft. However, the fitting cylinder has a configuration in which the peripheral surface of the metal cylinder is coated with fluororesin, and if the roundness is not high, the metal cylinder of the fitting cylinder does not move around the input shaft or the output shaft. Contact with the surface increases the contact resistance of the portion in contact with the metal cylinder, and thus the relative rotational resistance of the input shaft and the output shaft. As means for reducing this rotational resistance, the roundness by processing the fitting hole and the fitting portion is increased by eliminating the fitting cylinder, and at least one peripheral surface of the fitting hole and the fitting portion, It is described in FIGS. 1 to 3 of Patent Document 1 that an oil reservoir groove communicating with the oil passage of the hydraulic control valve is provided.

  However, in the case where the oil reservoir groove is provided as in Patent Document 1, the rigidity of the portion provided with the oil reservoir groove is lowered, and an improvement measure has been demanded.

  The present invention has been made in view of such circumstances, and the main object is to reduce the relative rotational resistance between the input shaft and the output shaft or torsion bar without reducing the rigidity of the fitting hole of the output shaft and the fitting portion of the input shaft. An object of the present invention is to provide a steering device that can be easily reduced.

  A steering device according to a first aspect of the present invention has a bar insertion hole, one end of which is connected to an operation member, a rotatable input shaft, one end fixed to the bar insertion hole, and the other end of the torsion bar And an output shaft having a fitting hole into which the other end of the input shaft is fitted, and at least one of the fitting hole and the fitting portion of the input shaft into the fitting hole, or the At least one of the fitting portion and the outer peripheral portion of the torsion bar has a coating layer of a fluororesin or a hard carbon-based material that should reduce the relative rotational resistance between the input shaft and the output shaft or the torsion bar. To do.

  A steering device according to a second aspect of the present invention has a bar insertion hole, one end of which is connected to an operating member, a rotatable input shaft, one end fixed to the bar insertion hole, and the other end of the torsion bar And an output shaft having a fitting hole into which the other end of the input shaft is fitted, and between the fitting hole and the fitting portion of the input shaft into the fitting hole, or the fitting And a bush made of a fluororesin or a graphite-based material that should reduce the relative rotational resistance between the input shaft and the output shaft or the torsion bar. It is characterized by that.

  In the steering device according to a third aspect of the invention, the bush has a slit in the axial length direction.

  In the first invention, since the coating layer of the fluororesin or the hard carbon material is provided at the relative rotation portion between the input shaft and the output shaft or the torsion bar, the rigidity of the relative rotation portion is not lowered. The relative rotational resistance can be reduced, and the relative rotational resistance can be easily reduced without increasing the number of parts, thereby reducing the cost of the steering device.

  In the second invention, since the bush of fluororesin or graphite material is provided at the relative rotation portion between the input shaft and the output shaft or the torsion bar, both the input shaft and the output shaft or the torsion bar are made of fluorine. The resin or graphite-based material can be brought into contact with the bush, and the relative rotational resistance can be reduced without reducing the rigidity of the relative rotational portion.

  In the third invention, since the bush can be reduced in diameter and enlarged even when the dimensional accuracy of the portion rotating relative to the input shaft and output shaft or torsion bar is rough, the input shaft and output shaft or torsion bar And processability can be improved.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
Embodiment 1
FIG. 1 is a cross-sectional view showing a configuration of a main part of a steering device according to the present invention, FIG. 2 is a cross-sectional view showing a configuration of a hydraulic control valve portion of the steering device, and FIG. 3 is a schematic diagram of the entire steering device.

  The steering device has a bar insertion hole 1a, one end of which is connected to a steering wheel A as an operation member, a torsion bar 2 whose one end is fixed to the bar insertion hole 1a, and other torsion bars 2 An output shaft 3 coupled to the end, a cylindrical valve body 4 connected to one end of the output shaft 3, and a valve body 4 fitted into the valve body 4 so as to be capable of relative angular displacement, and integrated with the outer peripheral portion of the input shaft 1 And a valve housing 6 in which the valve body 4 is accommodated. The valve body 4, the valve spool 5 and the valve housing 6 constitute a hydraulic control valve.

  The input shaft 1 includes a shaft body 11 having one end connected to the steering wheel A, and a cylindrical body 12 coupled to the other end of the shaft body 11. The cylindrical body 12 has a bar insertion hole 1a in the center, and a torsion bar 2 is inserted into the bar insertion hole 1a, and one end of the torsion bar 2 is connected to the base end of the cylindrical body by a dowel pin 7. In addition, a fitting portion 1b to be fitted into a fitting hole 3a described later is provided at the tip of the cylindrical body 12.

  The output shaft 3 has a fitting hole 3a at one end and a fitting hole 3b connected to the fitting hole 3a, and a pinion 8 at the other end. A fitting portion 1b is fitted into the fitting hole 3a so as to be relatively rotatable, and the other end of the torsion bar 2 is connected to the fitting hole 3b by spline fitting.

  On one of the peripheral surface of the insertion hole 3a and the outer peripheral portion of the insertion portion 1b, a coating layer 9 of a fluororesin or a hard carbon material that should reduce the relative rotational resistance between the input shaft 1 and the output shaft 3 is provided. . The coating layer 9 is made of a fluororesin which is a synthetic resin material having a small friction coefficient, or is formed by a diamond-like carbon (DLC) formed by a plasma CUD method, a sputtering method, an ion beam deposition method, a plasma ion implantation method, or the like. ), A coating layer of a hard carbon material that is either metal-containing DLC or carbon nitride, and is on the entire circumferential surface.

  The valve body 4 has a cylindrical shape integrally connected to one end of the output shaft 3 by a connecting pin 10, and can be displaced relative to the valve spool 5 within the range of torsion of the torsion bar 2. . The amount of this relative angular displacement is about 5 ° at the maximum.

  Inside the valve body 4, a plurality of first oil grooves 4 a each having an equal width are arranged in parallel in the circumferential direction, and each of the outer circumferences of the valve spool 5 is similarly arranged. A plurality of second oil grooves 5a having equal widths are arranged in parallel in the circumferential direction.

  The first and second oil grooves 4a and 5a are staggered in the circumferential direction in a neutral state where the torsion bar 2 is not twisted, and each of the first oil grooves 4a is between the second oil grooves 5a. Each of the second oil grooves 5a is opposed to the land between the first oil grooves 4a, and the first oil groove 4a is disposed on the fitting periphery of the valve body 4 and the valve spool 5. The oil chambers on the inner side and the oil chambers on the outer side of the second oil groove 5a are alternately arranged, and the communication portions between the oil chambers, that is, the widths of the first and second oil grooves 4a and 5a The groove edges on both sides in the direction act as throttle portions 4b and 5b that increase or decrease the respective communication areas (throttle areas) according to the relative angular displacement.

  Further, the valve body 4 has an oil supply hole 4c communicating with the discharge side of the hydraulic pump P serving as a hydraulic source, a first oil supply hole 4d communicating with one cylinder chamber of the hydraulic cylinder S, and the other of the hydraulic cylinder S. The valve spool 5 has a drain oil hole 5c that communicates with an oil tank T as a drain destination.

  The valve housing 6 is provided with ports 6a, 6b, 6c, 6d corresponding to the oil supply hole 4c, the first and second oil supply holes 4d, 4e, and the oil discharge hole 5c, respectively. , 6b, 6c, 6d and hydraulic pump P, hydraulic cylinder S, and hydraulic tank T are connected by oil pipes 20-23.

  In the steering device configured as described above, the torsion bar 2 is twisted via the input shaft 1 and the valve body 4 and the valve spool 5 are relatively moved when the steering wheel A is operated from the steering neutral position. Angular displacement occurs, and the pressure oil supplied from the hydraulic pump P to the first oil chamber 4a through the oil pipe 20, the port 6a and the oil supply hole 4c is controlled in flow rate by the throttle part 4b or 5b, and one oil supply hole 4d Alternatively, pressure oil is supplied from 4e to one cylinder chamber of the hydraulic cylinder S, the rack shaft R connected to one end of the piston of the hydraulic cylinder S moves in the axial direction, and the rack shaft R and the other end of the piston are connected to each other. A pair of connected wheels are turned.

  When the torsion bar 2 is twisted, the cylinder 12 of the input shaft 1 rotates with respect to the output shaft 3. One of the insertion hole 3a of the output shaft 3 and the insertion portion 1b of the cylindrical body 12 is provided with a coating layer 9 of a fluororesin or a hard carbon material, and this coating layer 9 is formed between the insertion hole 3a and the insertion portion 1b. Since it is in contact with the other, the rotational resistance of the input shaft 1 can be reduced without increasing the number of parts, and the cost of the steering device can be reduced.

Embodiment 2
FIG. 4 is a cross-sectional view illustrating a configuration of a main part of the second embodiment of the steering device. In this steering device, a bushing 24 made of a fluororesin or a graphite material whose relative rotational resistance between the input shaft 1 and the output shaft 3 is to be reduced is inserted between the insertion hole 3a and the insertion portion 1b.

  The bush 24 is a tube made of a graphite material formed by mixing a fluororesin material or graphite and a copper-based metal by a method such as sintering, and is externally fitted to the outer peripheral surface fitted in the fitting hole 3a and the fitting portion 1b. It has a cylindrical shape having an inner peripheral surface, and is fitted and held in one of the insertion hole 3a and the insertion portion 1b.

In the second embodiment, since the bush 24 is provided at the relative rotation portion between the input shaft 1 and the output shaft 3, both the input shaft 1 and the output shaft 3 are made of a fluororesin or graphite-based bush 24. The rotational resistance of the input shaft 1 can be reduced.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.

Embodiment 3
FIG. 5 is a perspective view of a main part showing the configuration of the third embodiment of the steering device. In this steering device, a bush 24 is provided with a slit 24a in the axial direction.
Since other configurations and operations are the same as those in the first and second embodiments, the same components are denoted by the same reference numerals, and the detailed description and description of the operations and effects are omitted.

Embodiment 4
This steering device loosely fits the bush 24 between the fitting hole 3a and the fitting portion 1b, and between the outer peripheral surface of the bush 24 and the fitting hole 3a, and between the inner peripheral surface of the bush 24 and the fitting portion 1b. There is a slight gap.

  In the fourth embodiment, since the gap and the bush 24 are provided in the relative rotation portion between the input shaft 1 and the output shaft 3, the rotational resistance of the relative rotation portion can be further reduced.

  In the first embodiment described above, the coating layer 9 is provided in one of the insertion hole 3a and the insertion portion 1b. However, the coating layer 9 may be provided in both the insertion hole 3a and the insertion portion 1b.

  FIG. 6 is a cross-sectional view showing a configuration of a main part of another embodiment of the steering device. In the first embodiment described above, the coating layer 9 is provided in at least one of the insertion hole 3a and the insertion portion 1b. In addition, the coating layer 9 is formed in the outer peripheral portion of the insertion portion 1b and the torsion bar 2 as shown in FIG. You may provide in one or both of these.

  Moreover, in Embodiment 2 demonstrated above, although the bush 24 was provided between the insertion hole 3a and the insertion part 1b, this bush 24 is other than the insertion part 1b and the outer peripheral part of the torsion bar 2 similarly to FIG. It may be provided between them.

  Further, the steering device according to the present invention may be a steering device provided with an electric motor in addition to a steering device provided with a hydraulic control valve.

It is sectional drawing which shows the structure of the principal part of the steering apparatus which concerns on this invention. It is sectional drawing which shows the structure of the hydraulic control valve part of the steering device which concerns on this invention. 1 is an overall schematic view of a steering apparatus according to the present invention. It is sectional drawing of the principal part which shows the structure of Embodiment 2 of the steering device which concerns on this invention. It is a perspective view of the principal part which shows the structure of Embodiment 3 of the steering device which concerns on this invention. It is sectional drawing of the principal part which shows other embodiment of the steering device which concerns on this invention.

Explanation of symbols

1 Input shaft 1a Bar insertion hole 1b Insertion section 2 Torsion bar 3 Output shaft 3
3a Insertion hole 9 Film layer 24 Bush 24a Slit

Claims (3)

  An input shaft having a bar insertion hole and having one end connected to the operation member and capable of rotation; a torsion bar fixed at one end to the bar insertion hole; and the other end of the torsion bar; In a steering apparatus comprising an output shaft having a fitting hole into which the other end is fitted, at least one of the fitting hole and the fitting portion of the input shaft into the fitting hole, or the outer peripheral portion of the fitting portion and the torsion bar At least one of them has a coating layer of fluororesin or hard carbon material which should reduce the relative rotational resistance between the input shaft and the output shaft or the torsion bar.   An input shaft having a bar insertion hole and having one end connected to the operation member and capable of rotation; a torsion bar fixed at one end to the bar insertion hole; and the other end of the torsion bar; In a steering device comprising an output shaft having a fitting hole into which the other end is fitted, between the fitting hole and the fitting portion of the input shaft into the fitting hole, or between the fitting portion and the outer peripheral portion of the torsion bar A steering device, wherein a bushing made of a fluororesin or a graphite material for reducing a relative rotational resistance between the input shaft and the output shaft or the torsion bar is inserted therebetween. The steering device according to claim 2, wherein the bush has a slit in an axial length direction.

Images