JPH0245111Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) This invention transmits the movement of the steering wheel to the rotary valve via the input shaft and torsion bar, and selectively supplies and discharges pressurized oil from the oil pump to the power cylinder to provide power for steering. The present invention relates to a hydraulic reaction force control device for a steering device.

(Prior technology) Conventionally, the power assist force of the power steering device is reduced at high speeds to make the steering wheel heavier and to eliminate wobbling, and to improve safety, pressurized oil is applied to the piston in the reaction force chamber according to the vehicle speed, etc. A hydraulic reaction force device that applies a reaction force to the input shaft by acting on the input shaft is well known, but in order to obtain a large reaction force, it is necessary to increase the oil pressure considerably, and this oil pressure increases the seal resistance of each seal part. It became larger, and had the disadvantage that there was a feeling of friction when steering, especially near the center position, making it difficult to return.

Also, a spring reaction force device that applies a central preset preload and reaction force to the input shaft using an elastic body such as a spring is well known, but it is not possible to obtain a large reaction force due to stress, space, etc. The drawback was that it could not be done.

It is also possible to arrange a cylindrical spring instead of the torsion bar to lower the hydraulic pressure applied to the cam follower and to make it easier to change the steering force. The manufacturing of cylindrical springs is extremely difficult because the spring constant must be as high as the torsion bar, requiring a large spring, and the spring constant requires strict precision in order to determine the valve characteristics. The problem was that it was difficult to

(Purpose) The present invention lowers the oil pressure supplied to the reaction force chamber to reduce seal resistance, reduces friction especially near the center during steering, improves the return of the steering wheel, and further obtains the necessary reaction force. It is an object.

(Function) According to the hydraulic reaction force control device of the present invention, the reaction force and the reaction force from the coil spring are both applied to the plunger using hydraulic pressure, and the oil pressure supplied to the reaction force chamber is reduced accordingly.

(Structure) The present invention is a rotary valve in which one end of a torsion bar is fixed to an input shaft connected to a handle, the other end of the torsion bar is fixed to an output shaft connected to a steering wheel, and the rotary valve is engaged with an outer circumferential groove at the center of the input shaft and an output shaft. The hydraulic pressure from the pump is controlled by the relative displacement with the groove to control the power auxiliary force, and a plurality of radial through holes are provided in a part of the output shaft, and the plunger is slidably inserted into each hole. In a hydraulic reaction force control device for a power steering system, a recess is provided outside the plunger, and the plunger is inserted into the input shaft in the recess. It is characterized by the inclusion of a coil spring that presses it to the side.

Next, a first embodiment of the present invention shown in FIGS. 1 and 2 will be described in detail.

The input shaft 1 is connected to a worm shaft 3 via a torsion bar 2, and one end of the torsion bar 2 is fixed to the worm shaft 3 by press-fitting it into the worm shaft 3 with a serration 4. After determining the neutral position of the valve, the pin 5 is fixed to the input shaft 1. The valve is composed of a groove 6 formed in the input shaft 1 and a groove 8 formed in the inner diameter part of the rotary valve 7.
When the input shaft 1 is twisted through the steering wheel, a relative displacement occurs between the input shaft 1 and the worm shaft 3 according to the reaction force from the road surface. occurs, and by switching the oil path of the valve, the pressure oil from the supply port 11 of the valve housing 10 is distributed to the cylinders 12, 13, the rack piston 14 is moved, and the sector shaft 15 is rotated.

FIG. 2 shows an embodiment of the hydraulic reaction force control device of the present invention, in which four hydraulic reaction chambers 49a to 49d are provided in the radial direction of the worm shaft 3 at one end of the worm shaft 3, and plungers 51a to 49d are provided inside the chambers. 51d is arranged to be slidable in the radial direction, and the plungers 51a to 51d
Coil springs 53a to 53d are compressed and inserted by band 52 into recesses 54a to 54d provided on the outside of are in pressure contact with the V-grooves 50a to 50d.

In addition, the recesses 54a of the hydraulic reaction force chambers 49a to 49d
-54d, hydraulic pressure is introduced in accordance with the vehicle speed and other signals by appropriate means, as in the configuration described in Japanese Patent Laid-Open No. 49-110037.

When relative torsion occurs between input shaft 1 and output shaft 2,
Plungers 51a to 51d have V grooves 50a to 50
d, the input shaft 1 receives pressure from the reaction hydraulic pressure and the springs 53a to 53d, thereby restricting relative torsion with the output shaft 2.

(Effects) According to the present invention, one end of the torsion bar is fixed to the input shaft connected to the handle, the other end of the torsion bar is fixed to the output shaft connected to the steering shaft, and the rotary bar is connected to the outer circumferential groove in the center of the input shaft and the output shaft. The power auxiliary force is controlled by controlling the hydraulic pressure from the pump by the relative displacement with the valve groove, and a plurality of radial through holes are provided in a part of the output shaft, and plungers are slidably inserted into each hole. In a hydraulic reaction force control device for a power steering device in which the tip fits into the input shaft tip groove and the outside of the plunger is a hydraulic reaction force chamber, a recess is provided outside the plunger, and the plunger is input into the recess. Since a coil spring is inserted that presses the shaft toward the shaft, it reduces the oil pressure supplied to the reaction force chamber, reduces seal resistance, reduces friction during steering, especially near the center, and improves the return of the steering wheel. In addition, the necessary reaction force can be obtained. In addition, by switching the valves using a torsion bar, the coil spring used to increase the stiffness near the neutral steering position only needs to be preloaded as shown in Figure 3, and the spring constant can be small, so a small coil spring can be used. Usable. Further, a coil spring that presses the plunger toward the input shaft can be compactly provided in the recess provided outside the plunger.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of an embodiment of the present invention, Fig. 2 is a side sectional view of the spring reaction device shown in Fig. 1, Fig. 3 is an explanatory diagram of the operation of the present invention, and Fig. 4 is the operation of the conventional device. It is an explanatory diagram. 1...Input shaft, 2...Torsion bar, 3...
Worm shaft, 7...Rotary valve, 49a~
49d...Hydraulic reaction force chamber, 50a-50d...V groove formed on the outer periphery of the input shaft 1, 51a-51d...Plunger, 54a-54d...Recessed portion.

Claims (1)

[Scope of utility model registration request] One end of the torsion bar is fixed to the input shaft connected to the handle, and the other end of the torsion bar is fixed to the output shaft connected to the steering wheel.The pump is activated by the relative displacement between the outer circumferential groove in the center of the input shaft and the rotary valve groove engaged with the output shaft. The power assist force is controlled by controlling the hydraulic pressure from the output shaft, and a plurality of radial through holes are provided in a part of the output shaft, and a plunger is slidably inserted into each hole, and the plunger tip is inserted into the input shaft tip groove. In a hydraulic reaction force control device for a power steering device in which the outside of the plunger is a hydraulic reaction chamber, a recess is provided outside the plunger, and a coil spring is placed in the recess to press the plunger toward the input shaft. A hydraulic reaction force control device for a power steering device, characterized in that it is equipped with an interposed device.