JPS61146674A - Steering-force controller of car in two-pump system - Google Patents

Abstract

PURPOSE:To reduce the dimension of the whole constitution and stabilize the operation by installing a means for reducing the relative angle shift between the input and output shafts through a torsion bar according to the car-speed on the output-shaft side, in the control of hydraulic pressure according to said relative angle shift. CONSTITUTION:In a hydraulic power steering apparatus, an input shaft 1 connected to a steering wheel and a pinion 3 engaged with the rack 2 of the output shaft on the steering-wheel side are connected through a torsion bar 4. The supply of pressurized oil into the right and left cylinders 10 and 11 is controlled by the relative-angle shift between the valve body 6 of a rotary valve and the input shaft 1. In this case, the through holes 15. in the radial direction are formed at a part of the pinion 3, and a plunger 16 is fitted, and the spherical head part 16a is engaged with the V-groove 1a in the axial direction which is formed onto the input shaft 1. The plunger 16 is urged by the pressurized oil supplied from a subpump 23 integrally installed with a main pump 22 through a control valve 25 which is controlled according to the output of a car-speed sensor 26.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a steering force control device for an automobile using a main pump for power steering and a sub-pump for steering reaction force.

(Prior Art) As shown in FIG. 5, a conventional steering force control device for an automobile controls the rotation of a rotating shaft 32 of an engine 31 by a pulley 33.
．． 34. It is transmitted to the main pump 36 by the belt 35, and oil from the oil tank 37 is supplied to the power steering device 38 to assist the steering force.Meanwhile, the mission counter shirt 839 rotations of the engine 31 are transmitted to the small pump 40, and the oil from the oil tank 37 is transmitted to the main pump 36. The oil from 37 is returned to the oil tank 37 via the throttle valve 41, and the pressure oil is introduced into the reaction force chamber 42 between the discharge port of the small pump 40 and the throttle valve 41 to generate a steering reaction force according to the vehicle speed. However, the off-the-shelf mission countershaft had the disadvantage that the discharge volume and pressure of the small pump could not be sufficiently increased, and the mission countershaft, oil tank, and reaction chamber were located far apart, so piping was required. The problem is that the space becomes large and when the vehicle speed is slow, the discharge amount from the small pump is insufficient, causing pulsation and pressure fluctuations.

In addition, as previously shown in Japanese Patent Publication No. 54-9368, the tip of a torsion bar, one end of which is fixed to an input shaft connected to a steering wheel, is fixed to a pinion shaft engaged with an output shaft connected to a steering wheel. A hydraulic power steering device is known in which the power assist force is controlled by controlling the hydraulic pressure by the relative angular displacement between the formed inner valve member and the outer valve member engaged with the pinion shaft, but a large hydraulic reaction force acts on the hydraulic power steering device. When this happens, an excessive load is applied to the pin that engages the outer valve member and the pinion shaft, causing play in the pin portion and causing damage, which is a major problem.

(Purpose) The present invention integrates a main pump for power steering and a small pump that obtains pressure oil for the hydraulic reaction chamber, and by driving the engine, the small pump can obtain sufficient discharge volume and oil pressure, and there is no sense of discontinuity. In addition to making it possible to obtain the desired pressure characteristics, the installation space is reduced to reduce the overall size, and even if a large hydraulic reaction force is applied, there is no excess load on the pin that engages the outer valve member and the pinion shaft. The purpose is to prevent the occurrence of backlash and damage to the pin portion due to no action, and to stabilize the operation of the valve itself.

(Structure) In order to achieve the above object, the present invention fixes the tip of a torsion bar, one end of which is fixed to an input shaft connected to a steering wheel, to a pinion shaft engaged with an output shaft connected to a steering shaft. In a hydraulic power steering device, the hydraulic power is controlled by the relative angular displacement between the inner valve member formed in the inner valve member and the outer valve member engaged with the output shaft fitted with the outer valve member with a small gap, thereby controlling the power assist force. , a plurality of through holes are provided in the radial direction in a part of the output shaft (pinion shaft) that engages with the outer valve member, and a plunger is slidably inserted into each hole, and the tip of the plunger is inserted into the vertical groove on the outer circumference of the input shaft. At the same time, a sealing material is placed on both sides of the plunger (in the direction of the pinion axis) to form a hydraulic reaction chamber, and the main pump for power steering and the sub-pump for steering reaction force have a common drive shaft. The main pump's discharge port is connected to the power steering input of the rotary valve, and a control valve is installed between the sub-pump's discharge port and the hydraulic reaction chamber passage, and the control valve is controlled by the signal from the vehicle speed sensor to adjust the vehicle speed. The plunger is pressed inward by supplying pressurized oil corresponding to the pressure into the hydraulic reaction chamber, thereby reducing the relative angular displacement between the input shaft and the output shaft, thereby reducing the power assist force. be. A detailed explanation will be given below based on examples.

An input shaft 1 connected to a handle (not shown) is fixedly integrated at each end by a pinion 3 and a torsion bar 4 that mesh with a rack 2 of the output shaft. A drive pin 5 is press-fitted into the large end of the pinion 3, and
The valve body 6, which is the outer member of the rotary valve, is engaged with and integrated with a groove 7 without play in the rotational direction. The inner side of the valve body 6 is fitted with the outer diameter part of the input shaft with a slight clearance, forming a known rotary valve, and the torsional action of the torsion bar 4 causes a gap between the input shaft 1 and the pinion 3. produces a relative angular displacement.

- Two seal rings 12.1 are installed on the pinion head.
3 are provided to form a hydraulic reaction force chamber 14. The hydraulic reaction chamber 14 is provided with four holes in the radial direction perpendicular to the pinion axis, and one hole 15 for the plunger. It is now able to move. The tip of the plunger 16 has a spherical head 16a, and a V groove 1a extends in the axial direction at one end of the input shaft.
It is designed to come into contact with. a plurality of V grooves 1a of the input shaft;
The positional relationship between the plunger hole and the 15° drive pin 5 is precisely aligned so that the reaction force is zero at the valve neutral position of the rotary valve (valve body 6, input shaft 1). 21 is the main pump 22 and sub pump 2
This is a compound pump consisting of 3 and 3, which share a common drive shaft 24 and are driven by an engine (not shown). Pressure oil discharged from the main pump 22 is supplied to the import 8 of the rotary valve. On the other hand, a control valve 25 is disposed in the passage between the sub-pump 23 and the hydraulic reaction chamber 14.

The control valve 25 is controlled by an electronic control device 27 operated by a signal from a vehicle speed sensor 26.

Next, the effect will be explained. When the engine operates, the drive shaft 24 of the compound pump 21 rotates, and the pressure oil discharged from the main pump 22 is supplied to the rotary valve import 19 and selectively supplied to the right cylinder 10 or the left cylinder 11. In this example, when steering to the right, the pinion 3 does not rotate due to the rotation of the input shaft 1 because it is engaged with the rack 2 which does not move due to the turning resistance, and therefore causes a torsional displacement to the torsion bar 4. This causes a displacement between the valve bodies 6, and pressure oil from a pump (not shown) is supplied from the import 8 to the right cylinder 10 for power assist. On the other hand, the return oil from the left cylinder 11 is returned to the return port 9→tank (not shown). At this time, the electronic control unit 27 supplies pressurized oil from the import 19 to the hydraulic reaction force chamber 14 in accordance with the vehicle speed, thereby pushing the plunger 16 inward. The input shaft 1 is displaced as shown in Fig. 4, and a portion of the plunger 16 is fitted into the pinion side hole, so the input shaft 1 moves upward while contacting the left slope 1a of the input shaft 1, and the reaction force Since it is loaded radially inward due to pressure, it receives a downward load. That is, it functions to return the V-groove 1a to the zero point.

Therefore, the driver receives a conventional torsion bar reaction force and a vehicle speed-sensitive hydraulic reaction force when steering the vehicle, so that the driver can receive a steering sensation that corresponds to the vehicle speed.

In addition, even when the steering wheel is in a neutral state (straight ahead state) when driving at high speed, when reaction pressure oil is applied to the hydraulic reaction force chamber 14, the plunger moves the pressure load radially inward at the initial position as shown in Figure 3. In response to this, the pinion 3 and input shaft 1 are integrated via the plunger 16, and the power assist force is removed and normal manual steering is performed, increasing the neutral rigidity of the steering wheel and allowing safe steering without wobbling. .

(Effects) According to the present invention, the tip of the torsion bar, one end of which is fixed to the input shaft connected to the steering wheel, is fixed to the pinion shaft engaged with the output shaft connected to the steering shaft, and the inner valve is formed as a part of the input shaft. In a hydraulic power steering device that controls power assist force by controlling oil pressure by relative angular displacement between a member and an outer valve member engaged with an output shaft that fits with the outer valve member with a small gap, the outer valve member and A plurality of through holes are provided in a part of the engaged output shaft (pinion shaft) in the radial direction, and a plunger is slidably inserted into each hole, and the tip of the plunger is fitted into a longitudinal groove on the outer circumference of the input shaft. Seal material is provided on both sides of the plunger (pinion axis direction) to form a hydraulic reaction chamber, and the main pump for power steering and the sub-pump for steering reaction force have a common drive shaft.
The main pump's discharge port is connected to the power steering input of the rotary valve, and a control valve is installed between the sub-pump's discharge port and the hydraulic reaction chamber passage, and the control valve is controlled by the vehicle speed and signals from the sensor. Pressure oil corresponding to the vehicle speed is supplied to the hydraulic reaction chamber to push the plunger inward, reducing the relative angular displacement between the input shaft and output shaft and reducing the power assist force, resulting in a large hydraulic reaction. Even when force is applied, no extra load is applied to the pin that engages the outer valve member and the pinion shaft, preventing rattling and damage to the pin part and stabilizing the operation of the valve itself. . -In addition, the sub-pump can obtain sufficient discharge volume and oil pressure due to the engine drive, and pressure characteristics with no sense of discontinuity can be obtained.In addition, the installation space has been reduced to reduce the overall size, and the input signals from various sensors have been reduced. Controlled by an electronic control device, it is possible to accurately control the pressure oil to the pressure chamber and obtain the correct steering force.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of an embodiment of the present invention including an oil passage system, Fig. 2 is a plane sectional view taken along the line A-A in Fig. 1, and Fig. 3 is an enlarged plan view of the main parts of Fig. 2; Figure 4 is a plan view of main parts during operation in Figure 3, and Figure 5.
The figure is an oil path diagram of a conventional device. 1...Input shaft, 1a...V groove, 3...Pinion. 4... Torsion bar, 5... Drive pin, 6...
... Valve body, 7... Groove, 14... Hydraulic reaction chamber, 15... Plunger hole, 16... Plunger, 16a... Spherical head of plunger, 21... Compound pump, 22...Main pump, 23...Sub pump, 24...Drive shaft, 25...Control valve, 26...Vehicle speed sensor, 27...Electronic control device patent applicant Koyo Automatic Machinery Co., Ltd. Co., Ltd. Figure 2 I9 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] The tip of the torsion bar, one end of which is fixed to the input shaft connected to the steering wheel, is fixed to the pinion shaft engaged with the output shaft connected to the steering wheel, and the inner valve member formed in a part of the input shaft and a small gap between this In a hydraulic power steering device, a power assist force is controlled by controlling oil pressure by relative angular displacement between an outer valve member engaged with an output shaft fitted with a pinion. A plurality of through holes are provided in the radial direction in a part of the input shaft, and a plunger is slidably inserted into each hole, and the tip of the plunger is fitted into a vertical groove on the outer circumference of the input shaft. The main pump for power steering and the sub-pump for steering reaction force have a common drive shaft, and the discharge port of the main pump is used for power steering of the rotary valve. A control valve is connected to the import and installed in the passage of the sub-pump discharge port and the hydraulic reaction chamber, and the control valve is controlled by the signal from the vehicle speed sensor to supply pressurized oil to the hydraulic reaction chamber according to the vehicle speed. A steering force control device for an automobile using a two-pump system that presses a plunger inward to reduce relative angular displacement between an input shaft and an output shaft, thereby reducing power assist force.