JP3299587B2 - Power steering reaction force device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering reaction device for operating a power assist actuator while relatively rotating an input shaft and an output shaft.

[0002]

2. Description of the Related Art In a conventional apparatus, an input shaft and an output shaft are connected via a torsion bar, and a torsional force of the torsion bar when the two shafts are relatively rotated is a pseudo reaction force. .

In the conventional reaction device as described above, the reaction force is uniquely determined by the rigidity of the torsion bar. When running, the steering wheel is too light, and the running stability is impaired. Conversely,
In order to maintain running stability at high speeds, there was a conflicting problem that the reaction force during stationary operation became too large. SUMMARY OF THE INVENTION It is an object of the present invention to provide a device in which a steering reaction force can be freely adjusted to improve the steering characteristics of a vehicle.

[0003]

According to the present invention, an input shaft and an output shaft are provided in a casing, and a power steering device for operating a power assist actuator by relatively rotating the input shaft and the output shaft. Force device is assumed. While assuming the above equipment ,
In the invention according to claim 1, the bellows arranged in parallel with the axis direction of the input shaft and the bellows arranged in parallel with the axis direction of the input shaft allow relative movement only in the axis direction of the input shaft. comprising yoke and, a side bushing which is provided opposite to the yoke fixed to the output shaft, the bellows
Is fixed to a ring whose one end is fixed to the input shaft.
Is fixed to the yoke and the elastic force
The yoke is pressed toward the side bush, and inclined grooves which gradually become shallower in the circumferential direction are formed at the same location on the circumference of the opposing surface of the yoke and the side bush. An electromagnet is fixed to the casing, a permanent magnet is fixed to the yoke, and the two magnets are opposed to each other.The permanent magnet has one polarity on the side facing the electromagnet. Have
A controller for controlling the exciting current of the electromagnet is provided on the opposite side to the opposite surface, and a controller for controlling the exciting current of the electromagnet is provided. The feature is that it is configured to move only in the direction. Further, the second invention is an electromagnetic
When the stone to the exciting current is not applied, the pressing force to the side bush side of the yoke is increased by the elastic force of the bellows itself, the pressing force to the side bush side of the yoke becomes smaller when the excitation current is applied The feature is that it is configured.

[0004]

Since the present invention is configured as described above,
By controlling the exciting current to the electromagnet, the yoke can be moved against the elastic body. If the yoke moves against the elastic body in this manner, the pressing force against the ball interposed between the side bush and the yoke becomes weaker, and accordingly, when the input shaft and the output shaft are relatively rotated, Is small, and eventually the steering reaction force can be reduced.

According to the reaction force device of the present invention, the steering reaction force can be freely adjusted according to the traveling conditions, so that stable traveling can always be realized, and the steerability can be improved. In the present invention, the relative rotation is restricted only by the elastic body.
It can reduce hysteresis of moving parts and reduce the number of parts.
It can be significantly reduced. Further, the present invention provides a yoke
Is placed parallel to the axis of the input shaft to excite the electromagnet.
Magnetic or de-energized allows the yoke to move
The device is compact because it is moved only in the direction
And a single yoke suffices for easy control
There are effects such as

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment shown in FIGS. 1 to 4 rotatably supports an output shaft 2 having a pinion 1 and an input shaft 3 linked to a steering wheel (not shown) in a casing C. are doing. The two shafts 2 and 3 are connected via a torsion bar 4. A rotary sleeve 5 is fixed to the output shaft 2 with pins 6 and a rotary pool 7 is integrally formed with the input shaft 3. The rotary sleeve 5 and the rotary pool 7 form a rotary valve V. Constitute. The output shaft 2 is formed integrally with the pinion 1, and the pinion 1 is engaged with a rack formed on the rack shaft 8. This rack shaft 8
The thrust is exerted by a power cylinder (not shown), and wheels are linked to both ends thereof.

Now, when the input shaft 3 is rotated by turning the steering wheel, the rotational force is transmitted to the output shaft 2 via the torsion bar 4. However, since the ground contact resistance of the wheels acts on the output shaft 2 via the rack shaft 8, the output shaft 2 does not rotate at this time, and the two shafts 2 and 3 are relatively rotated while twisting the torsion bar 4. Rotate. Thus, output shaft 2
When the input shaft 3 and the input shaft 3 rotate relative to each other, the rotary sleeve 5 of the rotary valve V and the rotary spool 7 are switched to supply pressure oil to one of the power cylinders and communicate the other to the tank. As a result, the power cylinder operates and supplies pressure oil to the rack shaft.

When the power cylinder operates, the rack shaft 8 moves accordingly, so that the wheels linked to the rack shaft 8 are steered. When the handle is stopped at a certain operation position, the input shaft 3 also stops, but the output shaft 2 is
Stop when you catch up with. That is, when the output shaft 2 catches up with the input shaft 3, the relative position between the rotary sleeve 5 of the rotary valve V and the rotary pool 7 becomes the same as in the neutral state, so that the operation of the power cylinder stops, and the rack The shaft 8 and the output shaft 2 will also stop. A side bush 9 shown in FIG. 2 is fixed to one end of the rotary sleeve 5 as described above. A yoke 10 is slidably fitted to the input shaft 3, and one side of the yoke 10 faces the side bush 9.

As shown in FIGS. 2 and 3, three inclined grooves 11 and 12 are formed on the opposing surfaces of the side bush 9 and the yoke 10 at predetermined intervals in the circumferential direction. The inclined grooves 11 and 12 have wall surfaces 11 on both sides thereof.
The grooves 12a and 12a are formed, and the depth of the groove at the center thereof is made the deepest, and the depth is gradually reduced toward the circumferential direction. The inclined grooves 11 and 12 of the side bush 9 and the yoke 10 are opposed to each other, and the ball 13 is interposed between the opposed inclined grooves. The yoke 10 as described above is slidable between the input shaft 3 and the input shaft 3 via a bearing 14.
On the side opposite to the side where the above-mentioned inclined groove 12 is formed, a metal
-15 is fixed at one end. The other end of the bellows 15 is fixed to a ring 16, which is fixed to the input shaft 3 with a set screw 17. Therefore, the yoke 10 strongly holds the ball 13 with the side bush 9 by the action of the elastic force of the bellows 15.

Further, a cylindrical portion 1 is provided around the yoke 10.
0a is formed, and a permanent magnet 19 is provided inside the cylindrical portion 10a. In the permanent magnet 19, an N pole appears on the side of the bonding surface with the cylindrical portion 10a, which is the outside, and an S pole appears on the inside opposite thereto. An electromagnet 20 is fixed to the casing C, and the electromagnet 20 is opposed to the S pole side inside the permanent magnet. The electromagnet 20 is connected to a controller 22 via a connector 21. The controller 22 includes a vehicle speed sensor 23, a pressure sensor 24 for detecting a load pressure of a power cylinder, a lateral acceleration sensor 25 for detecting a lateral acceleration of the vehicle, and an adjustment volume 2 for adjusting a steering force gain.
6 are connected.

Next, the operation of the first embodiment will be described.
When the electromagnet 20 is not excited, the movement of the ball 13 in the inclined grooves 11 and 12 is restricted because the yoke 10 is strongly pushed toward the side bush 9 by the elastic force of the bellows 15. Therefore, when the input shaft 3 and the output shaft 2 are relatively rotated, a stronger force is required. In other words, the steering operation feeling becomes heavy and the neutral rigidity is increased. Therefore, during high-speed traveling, the electromagnet 2
If the controller 22 is set so that no current is applied to 0, the running stability during high-speed running will be improved. Conversely, when the vehicle is traveling at a low speed, the controller 22 is operated to increase the current applied to the electromagnet 20.
However, the direction of the applied current is controlled in accordance with the right-hand screw rule of ampere so that the yoke 10 generates a magnetic field that moves against the elastic force of the bellows 15.

Therefore, the lower the vehicle speed, the lower the pressing force of the yoke 10. If the pressing force by the yoke 10 becomes weak in this way, the steering reaction force is only the torsional reaction force of the torsion bar 4, and the steering wheel operation feeling is relatively reduced. Pressing force by the yoke 10
The stronger the ball, the more the ball 1 in the inclined grooves 11 and 12
3 is restricted, so input shaft 3 and output shaft
In order to rotate the 2 relatively, a stronger force is needed
You. In other words, the handle operation feeling becomes heavy
In addition, the neutral rigidity is increased. Therefore, high
The running stability during high-speed running is improved. The second embodiment shown in FIGS. 5 to 8 is of a type in which the inclined walls 11 and 12 formed in the side bush 9 and the yoke 10 do not have the wall surfaces 11a and 12a as in the first embodiment. However, if the side surfaces of the inclined grooves 11 and 12 are opened as described above, the stability of the ball 13 is impaired. Therefore, a plate-shaped retainer 27 for stabilizing the ball 13 is provided. Other configurations are the same as in the first embodiment.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a perspective view of a side bush according to the first embodiment.

FIG. 3 is a perspective view of a yoke according to the first embodiment.

FIG. 4 is a side view of the first embodiment with a ball inserted between a side bush and a yoke.

FIG. 5 is a perspective view of a side bush according to a second embodiment.

FIG. 6 is a perspective view of a retainer according to a second embodiment.

FIG. 7 is a perspective view of a yoke according to a second embodiment.

FIG. 8 is a side view of the second embodiment with a ball inserted between a side bush and a yoke.

[Explanation of symbols]

 C casing 2 output shaft 3 input shaft 4 torsion bar 9 side bush 10 yoke 11 inclined groove 12 inclined groove 13 ball15 Bellow 16 rings  19 permanent magnet 20 electromagnet 22 controller

Claims (2)

(57) [Claims] 1. A power steering reaction device for providing an input shaft and an output shaft in a casing, and operating a power assist actuator by rotating the input shaft and the output shaft relative to each other. a bellows which is arranged parallel to the axial direction of the shaft, arranged parallel to the axial <br/> line direction of the input shaft, a yoke to relatively movable only in the axial direction of the input shaft, the A ring having a side bush fixed to the output shaft and opposed to the yoke, wherein the bellows has one end fixed to the input shaft.
With the other end fixed to the yoke, and
The yoke is pressed toward the side bush by natural force
Further, at the same location on the circumference of the opposing surface of the yoke and the side bush, inclined grooves which gradually become shallower in the circumferential direction are formed, and a ball is interposed between these inclined grooves. An electromagnet is fixed to the yoke, and a permanent magnet is fixed to the yoke, and these two magnets are opposed to each other. The permanent magnet has one polarity on the side facing the electromagnet and is opposite to the opposite face. A controller that controls the exciting current of the electromagnet, and that excites or de-energizes the electromagnet to move the yoke only in the axial direction of the input shaft. A reaction device for power steering, characterized in that: 2. When the exciting current is not applied to the electromagnet, the pressing force on the side bush side of the yoke increases due to the elastic force of the bellows itself, and the exciting current is applied.
The reaction force device for a power steering according to claim 1 , wherein a pressing force of the yoke toward the side bush is reduced.