JPS6222833B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a power steering device in which the reaction force for a steering operation of an automobile is provided by a torsion bar disposed within a worm shaft.

In general, this type of power steering device is required to provide a moderate reaction force to steering, that is, a moderate response to steering operation, and in integral type or semi-integral type power steering devices, The reaction force is applied by a torsion bar disposed within the worm shaft so as to pass through the rotary valve.

Therefore, since the reaction force exerted by the torsion bar is determined by the spring constant of the torsion bar, the steering force of the steering wheel is set to a predetermined force.

However, fatigue caused by a driver's steering operation is caused by the difference between the steering force most suitable for the driver's steering operation and the predetermined steering force actually required for the steering operation. Since the most suitable steering force for operation differs depending on each driver, if such a steering force can be adjusted according to each driver, the degree of fatigue caused by the driver's steering operation can be reduced. is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power steering device that can adjust the steering force to suit each driver and reduce the driver's fatigue due to steering operations.

Therefore, in the power steering device of the present invention, in which the reaction force of the steering operation is applied by a torsion bar disposed within the worm shaft, the power steering device further includes a slider fixed to the tip of the torsion bar. A spring plate having a split, a spring bar fixed to one end of the worm shaft and passed through the long hole, slot, etc. with the tip facing outward; It includes a pressing plate arranged so as to be in contact with the tip, and a plate lifter that drives the pressing plate so as to press the spring bar against the worm shaft side.

Preferred specific examples of the power steering device according to the present invention will be described below with reference to the drawings.

1 and 2 show a tenth embodiment of the power steering device of the present invention.

The power steering device 10 is of an integral type, and includes a worm shaft 13 built into a cylinder chamber 12 of a power steering casing 11;
A torsion bar 14 is disposed within the worm shaft 13 and connected to the yoke 19, and a torsion bar 14 is connected to the worm shaft 13 by a ball screw, with a large number of balls 16 placed in opposed screw grooves, and the cylinder chamber 12 is connected to the worm shaft 13. A power piston 15 is arranged to be able to reciprocate and slide within the power piston 15, a sector shaft 17 is meshed with the rack of the power piston 15, and a power steering casing 11 on the yoke 19 side thereof.
Rotary valve integrated within (not shown)
The torsion bar 14 is fixed to the tip of the torsion bar 14 and has slots 22 and 2 on both sides.
A spring plate 20 having a slot 2 fixed to one end of the worm shaft 13 and having a slot 2 with the tip facing outward.
Spring bars 24, 25 passed through 2, 23
, a pressing plate 26 arranged so as to be in contact with the tips of the spring bars 24 and 25, and a pressing plate 26 arranged so as to press the spring bars 24 and 25 against the worm shaft 13 side. The plate lifter 27 drives the plate lifter 27.

That is, the spring plate 2 described above
0, spring bars 24, 25, pressing plate 26 and plate lifter 27
The power steering casing 11
It is built into one end of the.

Therefore, one end of the power steering casing 11 is extended outward to a length that allows the plate 20, spring bars 24, 25, pressing plate 26 and plate lifter 27 to be incorporated therein. A partition wall 28 that rotatably supports the distal end of the worm shaft 13 is screwed into an appropriate position inside one end of the power steering casing 11 thus extended.

The distal end of the worm shaft 13 is threaded and penetrates the partition wall 28 from the inside at approximately the center thereof, and the threaded distal end is provided with a material that restrains the movement of the worm shaft 13 in the axial direction. A ring 29 for
The ring 29 is tightened by a nut 32.

Of course, thrust bearings 30 and 31 are arranged on both sides of the ring 29, and the ring 29
and its thrust bearings 30, 31 are
It is housed in a threaded bore formed on the outside of the partition wall 28 and is further tightened by threading a locking ring 33 into the bore.

Spring bars 24 and 25 are fixed to the tip of the worm shaft 13, which is rotatably supported by the partition wall 28 in this manner.

The spring bars 24 and 25 are bent into a substantially L shape from spring steel wire, with one end of each facing outward, and the other end connected to the tip of the worm shaft 13 through a nut 34. It is attached to.

Also, considering the strong installation of the spring bars 24 and 25, the spring bars 2
4 and 25 are made by bending and forming a single spring steel wire into a so-called open leg shape, and furthermore, in the center part,
It is desirable to form a ring-shaped part that is fitted into the tip of the worm shaft 13. In that case, the ring-shaped part is fitted into the tip of the worm shaft 13 and fixed by tightening the nut 34. Ru.

Furthermore, a spring plate 20 is fixed to the tip of the torsion bar 14 that projects outward from the tip of the worm shaft 13.

The spring plate 20 has a length that allows it to rotate within the power steering casing 11, and has a hole 21 at approximately the center and slots 22 and 23 at both ends. It is formed.

The spring plate 20 thus formed has the above-mentioned spring bars 24, 25.
are received in the slots 22 and 23, respectively, and the hole 21 is fitted into the tip of the torsion bar 14, and is fixed by tightening the nut 35.

Of course, the hole 2 of the spring plate 20
1, and the portion at the tip of the torsion bar 14 into which the hole 21 is fitted is knurled to prevent the spring plate 20 from rotating due to loosening of the nut 35. ing.

In addition, power steering casing 1
A pressing plate 26 is located inside one end of 1.
are arranged so as to be in contact with the tips of the spring bars 24 and 25 mentioned above.

The pressing plate 26 is formed from a steel plate into a disc shape and is arranged in the power steering casing 11 so as to be able to slide back and forth.

The pressing plate 26 thus arranged is driven by a plate lifter 27.

The plate lifter 27 is connected to the operating rod 36
and a lift plate 37 integrally formed at one end of the operating rod 36.

The plate lifter 27 is powered by a power source to drive the pressing plate 26.
The operating rod 36 is disposed inside one end of the steering casing 11, and the other end of the operating rod 36 projects outward from the end surface of the power steering casing 11.

Furthermore, the lift of the plate lifter 27
Plate 37 and its pressing plate 26
A thrust bearing 40 is disposed between the power steering casing 11 and the operating rod 36, and a rubber boot 39 seals the end surface of the power steering casing 11 and the operating rod 36.

The plate lifter 27 is operated by a hydraulic or pneumatic actuator (not shown) that can be operated by a driver, or via a link mechanism (not shown) or a cable (not shown). The operating rod 36 is reciprocated in the axial direction.

Of course, the power steering device 1 of this invention
Power steering casing 1 at 0
1 has the above-mentioned partition wall 28, spring bars 24, 25, and spring plate 2.
0. In order to incorporate the pressing plate 26, plate lifter 27, etc., it is desirable that the end face thereof be used as a cover and bolted.

Next, power steering device 1 of this invention
The operation of 0 will be explained.

When the above-mentioned spring bars 24, 25 are in the normal position, that is, when the pressing plate 26 is not lifted by the plate lifter 27, as shown in FIG. 24 and 25 are located near the fixed part with the worm shaft 13,
Slots 22, 23 in spring plate 20
are sandwiched between each.

That is, from the fixed part of the spring bars 24, 25 and the worm shaft 13 to the slots 22, 2 of the spring plate 20.
3, the amount of deflection of the spring bars 24, 25 and the spring plate 20 is small. small spring bars 24, 25
The deflection of the spring plate 20 provides a predetermined reaction force to the steering operation. Of course, if the amount of deflection of the spring bars 24, 25 and the spring plate 20 is extremely small, the reaction force of the steering operation will be under almost the same conditions as the reaction force provided by the existing torsion bar alone. The steering wheel can then be rotated with a predetermined operating force.

In addition, the actuator can be
Plate lifter 27 via a link mechanism etc.
is driven toward the worm shaft 13 side, the pressing plate 26 is lifted, and the tips of the spring bars 24 and 25 are pushed outward while contacting the pressing plate 26, and further, the pressing plate 26 is lifted.・Plate 2
6 is lifted to the extent that it almost touches the spring plate 20, the spring bar 2
4 and 25 are placed in the state shown by the two-dot chain line in FIG.

That is, the spring bars 24 and 25 are respectively held in the slots 22 and 23 of the spring plate 20 at positions near their tips, and are separated from the fixed portion between the spring bars 24 and 25 and the worm shaft 13. Since the respective distances to the parts sandwiched by the slots 22 and 23 are longer, the spring bar 2
4, 25 and the spring plate 20, and therefore the torsion bar 14
The torsion can be small. Therefore, the reaction force to the steering operation becomes small, and the steering wheel can be rotated with a smaller operating force than the predetermined operating force in the above case.

Furthermore, although the plate lifter 27 has been described as being driven by the driver's operation, the actuator that drives the plate lifter 27 detects the load of the automobile and sends an input signal corresponding to the load. By connecting a load detection mechanism configured in this way, the reaction force of steering operation will be automatically adjusted according to the load of the vehicle, especially for vehicles such as trucks and buses where the total weight of the vehicle changes significantly. , the reaction force of the steering operation, which changes depending on the load, can be kept almost constant at all times.

According to the present invention configured as described above, it is possible to obtain a power steering device in which the steering force of the steering wheel can be adjusted to suit each driver, and the degree of fatigue caused by the driver's steering operation can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing a specific example of the power steering device according to the present invention, FIG. 2 is a partially enlarged cross-sectional view showing one end of the power steering device shown in FIG. 1, and FIG. It is a front view of a plate. 10...Power steering device, 13...
Worm shaft, 14... Torsion bar, 20... Spring plate, 22, 23
...Slot, 24,25...Spring bar, 26...Pressing plate, 27...
plate lifter.

Claims (1)

[Scope of Claims] 1. In a power steering device in which the reaction force of a steering operation is applied by a torsion bar disposed within a worm shaft, the torsion bar is further fixed to the tip thereof and has a slot. a spring bar fixed to one end of the worm shaft and passed through the slot with the tip facing outward; A power steering device comprising: a pressing plate disposed as shown in FIG.