JPS61291270A - Hydraulic pressure reaction controlling device for power steering device - Google Patents

Abstract

PURPOSE:To enable a reaction torque to vary smoothly by configurating a device in such a way that a fixed restrictor is provided for a pinion shaft, on which the plural number of reaction chambers is formed to the radial direction, and hydraulic return pressure is allowed to act on the end surface of a planger in the reaction chamber through the said restrictor. CONSTITUTION:A power steering device is provided with a reaction pressure control valve 22 equiped with a solenoid 24 which is electrically controlled depending on a car speed, on a hydraulic line from an oil pump to both a main valve 21 and a pressure chamber 31 so as to feed oil pressure proportional to a steering force while the car is running at a high speed, to the pressure chamber 31. The plural number of the reaction chambers 31 is formed to the radial direction around a pinion shaft 30 which is fitted onto the circumference of an input shaft 29, and a planger 32 is slidably fitted onto the circumference of an input shaft 29, and a planger 32 is slidably fitted in each of the pressure chamber 31. In this case, the pinion shaft 30 is provided with an orifice 33 made of synthetic resin having a large coefficient of linear thermal expansion to form a fixed restrictor of a small hole 33a in the orifice 33.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a hydraulic reaction force control device that presses the input shaft of a power steering device with hydraulic pressure at high speeds to obtain rigidity.

(Prior Art) FIGS. 4 and 5 show a conventional hydraulic reaction force control device for a power steering device. Pressure oil from the oil pump 1 is guided to the import 2a of the reaction pressure control valve 2. 3 is a main spool of the reaction pressure control valve 2, 4 is a sub spool, and the sub spool 4 is formed with a fixed throttle 4a connecting the reaction chamber side and the return outlet 2b, and the main spool 3 and the sub spool are When the variable throttle 5 on the reaction force chamber side is closed due to the relative displacement with respect to the variable throttle 5, the reaction pressure is prevented from rising due to pressure oil leaking from the gap between the rain spools. Pinion shaft 7 on the outer periphery of the input shaft 6
The plunger 9 in the reaction force chamber 8 is pressurized to press the concave groove 6a on the outer periphery of the input shaft 6 to obtain a steering reaction force.

However, in such a conventional hydraulic reaction force control device, the variable throttle 10 is closed to cut the reaction pressure when the vehicle is stopped or at low speed, but the reaction pressure control valve in particular performs hydraulic control. If the main valve is installed away from the main valve, the structure is not such that the pressure Pf inside the reaction force chamber is always greater than the pressure Pr2 on the input shaft side due to differences in the length of the return circuit and pipe resistance, so Pr2 When it is larger than Pf, the plunger protrudes outward, creating a gap between it and the concave groove of the input shaft, causing the plunger to come into contact with the reaction force chamber wall during steering, causing a catch, and the reaction force chamber side being variable. When the aperture opened, the plunger collided with the input shaft, making it impossible to obtain smooth changes in steering force. Furthermore, when the oil temperature rises and the viscosity of the hydraulic oil falls, there is a problem in that the amount of leakage from the fixed throttle 4a increases and the reaction pressure characteristics change.

(Purpose) The present invention has been made by focusing on the above-mentioned conventional problems.
The objective is to eliminate the fixed throttle formed on the sub spool of the conventional reaction force pressure control valve and provide a fixed throttle on the pinion shaft in the reaction chamber to eliminate the drawbacks of the conventional valve.

(Structure) In order to achieve the above object, the present invention cuts reaction pressure in the oil path from the oil pump to the main valve and reaction chamber when the vehicle is low or at low speed, and provides return pressure in the reaction chamber. At high speeds, the power steering system is equipped with a reaction pressure control valve that directs hydraulic pressure corresponding to the steering force to the reaction force chamber, and a fixed throttle is installed on the pinion shaft. It is characterized in that return pressure is applied to the rear end surface of the jar through the fixed throttle. A detailed explanation will be given below based on the embodiment shown in FIGS. 1 to 3. 21 is a main valve, and 22 is a reaction pressure control valve. Pressure oil from the oil pump flows into the import 23a of the valve housing 23, operates the solenoid 24 according to the vehicle speed, and controls the main spool 2.
5 and the auxiliary spool 26, it is selectively guided to the boat 27 on the power steering side or the port 28 on the reaction force chamber side.

Reference numeral 29 denotes an input shaft, which has four radial reaction force chambers 31 formed on the pinion shaft 30 on its outer periphery, a plunger 32 is slidably fitted therein, and the pinion shaft 30 is made of synthetic resin with a large coefficient of linear expansion. An orifice 33 is provided, and a fixed aperture consisting of a small hole 33a is formed in the orifice 33.

Next, the effect will be explained. When the vehicle is stopped or at low speed, the sub spool 26 is pulled to the left by the solenoid 24 as shown in Figure 3, and the variable throttle 34 on the reaction chamber side is closed, and only the variable throttle 35 on the main valve side is open. Since all the pressure oil from the oil pump 1 passes through the boat 27 and flows to the main valve 21 side, the reaction pressure does not increase and a light steering force can be obtained. At this time, since oil is not supplied into the reaction force chamber 31, a return pressure Pr2 acts on the input shaft side surface 32a of the plunger 32, and a reaction pressure Pf lower than Pr2 acts on the reaction force chamber side 32b. act. Then, oil at the return pressure Pr flows into the reaction chamber side through the small hole 33a of the orifice 33, so that both surfaces 32a and 32b of the plunger 32
The hydraulic pressures are balanced, and the plunger 32 is not displaced outside the reaction force chamber 31. Therefore, at high speed, solenoid 2
4, the sub spool 26 moves to the right, the variable throttle 34 on the reaction force chamber side opens, and when pressure oil acts on the rear surface of the plunger 32, the reaction torque changes smoothly.

Furthermore, if the orifice 33 is made of a material such as synthetic resin with a large coefficient of linear expansion, the diameter of the small hole 33a becomes small at high temperatures, so even if the viscosity of the oil decreases, the amount of oil leaking from the small hole 33a will be small. Changes in performance such as reaction force characteristics are kept small.

(Effects) The present invention cuts the reaction pressure in the oil path from the oil pump to the main valve and the reaction chamber when the vehicle is low or at low speeds, so that only return pressure acts on the reaction chamber. At high speeds, the system is installed in a power steering system equipped with a reaction pressure control valve that guides hydraulic pressure according to the steering force to the reaction force chamber, and a fixed throttle is installed on the pinion shaft, which is fixed to the rear end surface of the plunger in the reaction force chamber. Since the return pressure is applied through the throttle, it is possible to reliably prevent the plunger from being pushed outward and getting caught on the side wall of the reaction chamber, and when the reaction pressure is applied, the plunger The reaction torque can be changed smoothly without colliding with the input shaft.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of an embodiment of the present invention, FIG. 2 is a plan sectional view of the reaction force chamber shown in FIG. 1, FIG. 3 is a front sectional view of the reaction pressure control valve shown in FIG. The figure is a plan sectional view of a conventional reaction force chamber, and FIG. 5 is a front sectional view of a conventional reaction pressure control valve. 21... Main valve 22... Reaction pressure control valve 23... Valve housing 23a... Import 24... Solenoid 25... Main spool 2
6... Vice spool 27, 28... Boat 2
9...Input shaft 30...Pinion shaft 31
... Reaction force chamber 32 ... Plunger 33
... Orifice 33a ... Small hole 34 ...
Variable throttle 35 on the reaction force chamber side... Variable throttle procedure amendment on the main valve side (voluntarily submitted) August 12, 1985 Michibe Uga, Commissioner of the Patent Office 1, Indication of the case 1985 Patent application No. 132975 2, Name of the invention Hydraulic reaction force control device for power steering device 3, Relationship with the person making the amendment Patent applicant address 2, 333 Toichi-cho, Kashihara City, Nara Prefecture Name
Koyo Jidoki Co., Ltd. 4, Agent address: 2-2-5-5 Shinbashi, Minato-ku, Tokyo, Date of amendment order: 6, Subject of amendment: Specification and drawings 7, Contents of amendment (1) Specification, page 2 Line 13: “I’m here.” and R person axis 6
Insert and correct "Pressure oil from oil pump 1" between "...". (2) Correct "1o" on the 19th line of the second page to "5". (3) In the 6th line of the 3rd page of the same page, "with the groove" is corrected to ``with the groove 6a''. wall 8
Correct it with "a". (5) Amend Figure 4 of the drawings as shown in the attached sheet.

Claims (2)

[Claims] (1) In the oil path from the oil pump to the main valve and reaction chamber, cut off the reaction pressure when the car is low or at low speeds, and only allow return pressure to act on the reaction chamber, and when driving at high speeds, cut the reaction pressure. It is placed in a power steering device equipped with a reaction pressure control valve that guides hydraulic pressure according to the force to the reaction chamber, and a fixed throttle is installed on the pinion shaft, and the hydraulic pressure is returned through the fixed throttle on the rear end face of the plunger in the reaction force chamber. A hydraulic reaction force control device for a power steering device that allows pressure to act. (2) A hydraulic reaction force control device for a power steering device according to claim 1, wherein the fixed throttle is made of synthetic resin or the like having a large coefficient of linear expansion.