JPH10217989A - Power steering device for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To tighten an inner cable when it becomes loose and suppress its tensile force within a fixed scope so as to prevent the reduction of steering characteristics by turning a screw shaft in one direction by utilizing force by which a cylindrical terminal tool moves due to elastic force of a spring when tensile force of the inner cable is reduced. SOLUTION: When the elongation of an inner cable 6 and the wear of an outer tube 5 occur due to the use for a long time, a steering wheel is moved to one direction to turn a drum on steering wheel side 7 and loosen the inner cable 6, and a cylindrical terminal tool 3 is pressed in the direction in which it slip off out of a case 30 due to elastic force of a compression coil spring 39. At this time, a protrusion 50 of a screw shaft 40 comes into contact with or leaves a drive plate 37 and comes in and out of a guide groove. When the inner cable 6 is loosened furthermore, the protrusion 50 enters an engaging groove, the screw shaft 40 rotates by a fixed angle, and a male screw part 41 is screw-fitted in a nut 42. Consequently, a tensile force providing member 43 moves in the direction of the drum on steering wheel side 7 to give tensile force to the inner cable 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering apparatus for an automobile using two control cables and a power cylinder for applying a tensile force to an inner cable, and more particularly to a power steering apparatus for maintaining a constant tension applied to the inner cable. The present invention relates to a power steering device for an automobile.

[0002]

2. Description of the Related Art The applicant of the present application discloses a power cylinder having a piston rod connected to a front wheel via a steering link mechanism at both ends, and is supplied to the power cylinder and simultaneously discharged from the power cylinder. A rotary control valve for controlling the direction of pressurized oil, a valve-side drum connected to the rotor of the control valve, a handle-side drum connected to the handle, and a freely sliding inside the flexible outer tube. Patent application for a power steering apparatus for an automobile, wherein the inner cable inserted includes two control cables wound around both drums so that tensile force acts alternately when the handle side drum is rotated in an alternate direction. And
The application was published as JP-A-8-2431.

[0003]

However, according to the present invention, the inner cable is gradually elongated by use for a long time or the liner of the outer tube is worn, so that the tension of the inner cable is reduced and the handle of the handle is reduced. There is a problem that play is increased and steering characteristics are reduced.

[0004]

As means for solving the above-mentioned problems, a first aspect of the present invention provides a case for separately accommodating both drums and a spring elasticity fixed to the ends of both outer tubes. Two cylindrical terminal devices attached to at least one case so as to apply tension to the inner cable, and a screw shaft freely supported only by rotation between the two cylindrical terminal devices in the case, A nut screwed into a male screw portion of the screw shaft, and an engagement provided at a distal end portion of an arm extending on both sides of a fitting portion into which the nut is relatively freely movable only in a direction orthogonal to the center axis. A tension applying member having a member engaged with both inner cables routed between the cylindrical terminal device and the drum so that the inner cables are bent in a direction to separate or approach each other; Screw shaft turning means for turning the screw shaft in one direction by using the force of the cylindrical terminal device being pushed and moved by the spring elasticity when the tension of the screw becomes small. Then, when the inner cable is loosened, the cylindrical terminal is pushed by the spring elasticity to rotate the screw shaft in one direction, so that the tension applying member in which the nut fitted to the screw shaft is fitted is in the direction of the drum or the cylindrical shape. There is an effect that the steering characteristic is improved by moving in the direction of the terminal device to increase the bending of the inner cable, increase the tension thereof, and reduce the play of the steering wheel, and the steering characteristic is improved. Since the engagement member is a roller in the invention, it rotates with the movement of the inner cable, and the frictional force between the inner cable and the tension applying member is reduced to operate smoothly,
There is an effect that durability is improved, and the invention of claim 3 is the invention according to claim 1 or 2, wherein the screw shaft rotating means is a driving plate made of a spring plate fixed to a cylindrical terminal and a driving plate for the driving plate. An engagement groove that forms an oblique angle in the axial direction of the formed cylindrical terminal device, and a projection that is formed at equal intervals around the screw axis and rotates the screw shaft by a fixed angle by engagement with the engagement groove. When one of the inner cables is loosened, the cylindrical terminal moves in the direction of coming out of the case by spring elasticity, and the projection engages with the engagement groove forming an oblique angle, thereby causing the screw shaft to move. When the inner cable is rotated by a certain angle and the tension applying member moves to apply tension to the loosened inner cable, and the inner cable is no longer loose due to the reversal of the handle, the tubular terminal is retracted against the spring elasticity. When retreating, Maseru A than passing projections by, there is surely conducted can effect the invention of claim 1.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a handle, which is rotatably supported by a case 30 attached to a vehicle body.

A casing 2 is disposed at a steering position in front of the vehicle body, and two flexible control cables 4 fixed to a tubular terminal 3 at the terminal are provided between the two cases 30 and 2. Are being routed.

[0010] As shown in FIG. 2, the case 30 on the handle 1 side is formed by adding a press-formed portion 32 to a cast-formed portion 31.
The handle-side drum 7 is rotatably supported on the casting portion 31 around the rotation shaft 8, and the inner cable 6 is inserted into the outer tube 5 so as to be freely slidable. Cylindrical terminal 3 crimped to the end of outer tube 5 of control cable 4
Is a through hole 3 formed in the press-formed portion 32 of the case 30.
4 and the through-hole 35 formed in the casting part 31 is slidably inserted into the through-hole 35 to be mounted.

A male screw 36 is formed on the distal end side of the cylindrical terminal device 3, and a drive plate 37 having an L-shaped spring plate bent between the male screw 36 is sandwiched between two front and rear nuts 38 at an arbitrary position. And a compression coil spring 39 is mounted between the front nut 38 and the cast molding 31 to urge the cylindrical terminal 3 in the direction of pushing it out of the case 30. I have.

The inner cable 6 that has entered the casing 30 from the tubular terminal 3 is wound around the handle-side drum 7. As shown in FIGS. 4A and 4B, the winding directions of the two inner cables 6 around the handle-side drum 7 are opposite to each other, and the terminals are fixed to the handle-side drum 7.

A screw shaft 40 is freely supported for rotation only between the two cylindrical terminal devices 3 of the case 30, and a square nut 42 is provided at one end of the male screw portion 41 as shown in FIG. It is screwed.

As shown in FIGS. 2 and 3, the nut 42 is relatively slidably fitted into a box-shaped fitting portion 44 formed at the center of the tension applying member 43. 4
0 is formed, and an engaging member 47 made of a roller is rotatably supported at the tip of an arm 46 extending on both sides of the fitting portion 44, so that a cylindrical terminal device is formed. An engaging member 47 is hooked on the two inner cables 6 between the handle 3 and the handle-side drum 7 so as to draw the two inner cables 6 together.

A flange 49 is formed on the other end of the screw shaft 40, and projections 50 are formed on the outer periphery thereof at regular intervals. As shown in FIGS. An engagement groove 52 is formed at an oblique angle with a guide groove 51 parallel to the screw shaft 40 corresponding to the above.

On the steering position side, the end of the outer tube 5 is attached to the case 2 by a tubular terminal 3 in a direction perpendicular to the rotation axis of a drum (not shown).
Is wound around the drum similarly to the handle 1 side.

The rotating shaft of the drum at the steering position protrudes from one surface of the case 2 and is connected to a rotor 10 of a rotary valve 9 described later.

Reference numeral 14 denotes a cylinder tube 15 and a piston 1
6 is a power cylinder in which the piston 6 is slidably fitted, a rack 18 is formed by extending one side of a piston rod 17 fixed to the piston 16, and tie rods 20 are connected to both ends via ball joints 19. The tie rod 20 is connected to a front wheel a via a knuckle arm (not shown).

In the present invention, the tie rod 20, the knuckle arm and the like are collectively referred to as a steering link mechanism.

A pinion 21 is fixed to the rotor 10 of the rotary valve 9 and meshes with the rack 18.

The supply port 22 of the rotary valve 9 is connected to a hydraulic pump (not shown), and the discharge port 23 is connected to a tank (not shown).
5 is connected to two ports 26, 27 of the cylinder tube 15 by pipes 28, 29,
When 0 rotates in one direction, pressure oil is supplied to one side of the piston 16 and is discharged from the other side, and when rotated in the other direction, pressure oil is supplied to the other side of the piston 16 and discharged from one side. , The piston 16 operates together with the piston rod 17.

Next, the operation of this embodiment will be described.

When the handle 1 is rotated in one direction, the handle-side drum 7 rotates by an angle corresponding to that of the handle 1, and the inner portions of the two control cables 4 wound around the handle-side drum 7 and the drum at the steering position. One of the cables 6 is wound around the drum 7 on the handle 1 side to generate tension, and the inner cable 6 is paid out from the drum on the steering position side, and the drum and the rotating shaft rotate in one direction. At this time, the inner cable 6 of the other control cable 4 is drawn out from the handle-side drum 7 and wound up on the drum at the steering position.

When the handle 1 is rotated in the other direction, the drum on the steering position side and its rotating shaft rotate in the other direction by the same operation.

When the rotation shaft of the drum at the steering position rotates in one direction, the rotor 10 connected thereto rotates in the same direction, and the engagement between the pinion 21 and the rack 18 causes the piston rod 17 to operate in one direction. At this time, pressure oil is supplied from one of the ports 24 and 25 of the rotary valve 9 to one of the ports 26 and 27 of the power cylinder 14 by the rotation of the rotor 10 and the piston rod 1
7 operates in the same direction as above, and the wheel a faces one side via the steering link mechanism.

When the rotation center shaft 8 of the drum 7 at the steering position rotates in the other direction, the same operation causes the wheel a to face the other direction.

By using the inner cable 6 for a long time,
When the inner cable 6 on the side on which tension acts is loosened, or when the liner of the outer tube 5 is worn out, then when the handle 1 is turned over, there is play on the handle until tension is applied to the inner cable 6. In this embodiment, the steering characteristic is reduced, but the steering wheel 1 is turned in one direction and the handle-side drum 7 rotates in the direction of the arrow in FIG. The inner cable 6 on the upper side in the figure is loosened, and the upper cylindrical terminal 3 is pushed in the direction of coming out of the case 30 by the elastic force of the compression coil spring 39, so that tension is applied to the inner cable 6, and the handle 1 Are alternately reversed so that the upper and lower tubular terminal devices 3 alternately advance and retreat, and at this time, the protrusions 50 of the screw shaft 40 are moved as shown in FIG. Although the guide cable 51 relatively moves toward and away from the drive plate 37 and enters and exits the guide groove 51, when the inner cable 6 is further loosened, as shown in FIG. The screw shaft 40 relatively enters the mating groove 52 and rotates by a certain angle.

Then, the tension applying member 43 is moved in the direction of the handle side drum 7 by the screwing of the male thread portion 41 of the screw shaft 40 and the nut 42, and tension is applied to the inner cable 6.

When the upper cylindrical terminal 3 is retracted by reversing the handle 1, the protrusion 50 is
7 are relatively retreated while being elastically deformed.

By repeating the above operation, the inner cable 6 is tightened in accordance with its looseness, the tension of the inner cable 6 is kept within a certain range, and the deterioration of the steering characteristics is prevented.

In the above embodiment, the tension applying member 43 may be moved toward the cylindrical terminal 3 by the rotation of the screw shaft 40, and the engaging member 47 pushes the inner cables 6 on both sides. You may also do,
This tension maintaining device may be provided on the steering side.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of one embodiment of the present invention.

FIG. 3 is a partially cutaway front view of a tension applying member.

FIG. 4 is a perspective view showing a state in which an inner cable is wound around a drum.

FIG. 5 is a front view of the screw shaft rotating means.

FIG. 6 is a side view of the screw shaft rotating means.

FIG. 7 is an operation explanatory view of the screw shaft rotating means.

[Explanation of symbols]

 1: Handle 3: Cylindrical terminal 4: Control cable 5: Outer tube 6: Inner cable 7: Handle side drum 9: Control valve 10: Rotor 14: Power cylinder 17: Piston rod 20: Tie rod 30: Case 36: Male screw 37: drive plate 39: compression coil spring 40: screw shaft 41: male screw portion 42: nut 43: tension applying member 44: fitting portion 46: arm 47: engaging member 48: screw shaft rotating means 50: projection 52: engagement Groove a: Front wheel

Claims (3)

[Claims] 1. A power cylinder having a piston rod connected at both ends to a front wheel via a steering link mechanism, and a direction control of pressure oil supplied to the power cylinder and simultaneously discharged from the power cylinder. A rotary control valve, a valve drum connected to a rotor of the control valve, a handle drum connected to a handle, and an inner cable slidably inserted into a flexible outer tube. A power steering apparatus for an automobile including two control cables wound around the two drums so that a tensile force is applied alternately in the rotation of the handle-side drum in an alternate direction. A case, fixed to the ends of the outer tubes, and the inner casing Two tubular terminals attached to at least one of the cases so as to apply tension to the case, and a screw shaft freely supported only by rotation by the case between the two cylindrical terminals, A nut screwed into a male screw portion of the screw shaft; and an engagement provided at a distal end portion of an arm extending on both sides of a fitting portion into which the nut is relatively freely movable only in a direction perpendicular to the center axis thereof. A tension applying member in which a member is engaged with the inner cables arranged between the cylindrical terminal and the drum to bend in a direction to separate or approach the inner cables from each other; Screw shaft turning means for turning the screw shaft in one direction by utilizing the force of the cylindrical terminal device being pushed and moved by the spring elasticity when the tension of the inner cable becomes small. Self characterized by Power steering device for moving vehicles. 2. The power steering apparatus according to claim 1, wherein said engaging member is a roller. 3. The screw shaft rotating means, comprising: a driving plate formed of a spring plate fixed to the cylindrical terminal; and a member forming an oblique angle in an axial direction of the cylindrical terminal formed on the driving plate. 3. A mating groove, and a projection formed at equal intervals around the screw shaft and configured to rotate the screw shaft by a predetermined angle by engagement with the engaging groove. Automotive power steering device.