JPS5889469A - Power steering - Google Patents

Abstract

PURPOSE:To simplify the piping and to improve the mountability by integrating a control valve to be controlled by a microcomputer with a pump. CONSTITUTION:A hydraulic pump 20 is integrated with a flow control valve 21 and a reservoir 23. A PS control valve including a solenoid 35 to be controlled by a microcomputer is further integrated and conducted through a piping to a power cylinder. Since the control valve is integrated with the pump the piping is simplified to a improve the mountability and the assembling.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device for an automobile that uses hydraulic pressure to reduce steering force.

Normal power steering device = 1 on the steering wheel
It has a control pulp that mechanically detects the rotation of the connected input shaft and switches, and the switching operation of this valve selectively applies pressure oil to the power cylinder installed at the tip of the input shaft. The input shaft is supplied with a steering link so that the direction of the wheels is changed in proportion to the rotation of the input shaft.

In particular, in automobile power steering systems, in order to ensure safety, the tip of the input shaft is positioned so that the tip of the input shaft is aligned with the piston of the power cylinder so that steering operations can be performed even if hydraulic assist force cannot be obtained due to a failure of the hydraulic system. Mechanically interconnected via a ball and screw assembly.

By the way, the control valve that controls the direction of the pressure oil sent to the power cylinder by the rotation of the input shaft is
Since the movement of the input shaft is linked to the actual movement of the piston on the output side, and feedback control is performed, there are significant restrictions on its installation, and it is usually installed at the connection part of the input shaft to the power cylinder. are placed in a limited manner. In addition, in order to carry out such mechanical feedback control, the structure of the control valve is extremely complex, and in particular, the hydraulic pressure is controlled in response to the ground resistance of the wheels, which changes depending on the traveling speed, and the control valve is constantly controlled. In a speed-sensitive power steering system designed to obtain optimal steering force, the structure of the control valve has to be even more elaborate, resulting in poor maintainability, poor safety, and increased costs. There was a drawback that it also became.

On the other hand, control to obtain the optimum steering force according to various driving conditions is more important than intervention from the perspective of pursuing comfort and safety of automobiles.
Therefore, the present applicant developed a power steering system that uses a microcomputer to always obtain the optimum steering force under all driving conditions.
It is proposed as No. 96.

To explain this based on FIG. 1, an input shaft 2 connected to a handle 1 is connected to a piston 4 of a power cylinder 3 as a hydraulic actuator.

-3- In this case, the piston 4 is connected to the input shaft 2 and a ball (not shown).
The piston 4 is connected to the cylinder 3 depending on the rotational direction and speed of the input shaft 2.
slide inside.

A rack 5 is provided on the side surface of the piston 4, and a Hifter gear 6 is engaged with this rack 5, and a Pit 1-man arm 7 is interlocked with the sector gear 6 as the screw 1-4 moves.
A steering link (not shown) is driven through the link.

The piston 4 moves due to the input rotation of the input shaft 2, and in order to assist this movement with hydraulic pressure, a pump P Pressure oil is selectively controlled and supplied.

The control valve 9 is an electromagnetic valve whose operation is controlled by a microcomputer 10 to which the rotational direction and rotational force or rotational speed of the input shaft 2 are input, and the control load on the output side is fed back.

Here, 11 is the 0-domain attached to the shoe input shaft 2.
4 - A sensor consisting of a strain gauge or the like that detects the rotational force and direction of rotation by detecting the torsion of the input shaft 2. 12 is a magnetic pickup for similarly detecting the rotational speed of the input shaft 2.

These detected signals are input to the arithmetic control unit 15 of the microcomputer 10 via input interfaces 14 each having amplification and signal waveform processing functions.

The calculation control unit (CPU) 15 performs calculations based on these inputs, selects the stored value from the storage unit (ROM) 16 which stores the optimum value corresponding to the operating conditions in advance,
It outputs to the control valve 9 via the output interface 17.

The control valve 9 is composed of a solenoid valve, and the switching direction and switching amount are controlled based on an input signal, and mills the amount of pressure oil sent to the left and right oil chambers 8A and 8B of the power cylinder 3.

When operating the handle 1 to rotate the input shaft 2 in either direction, a reaction force proportional to the operating load applied to the piston 4 of the power cylinder 3 is generated on the input shaft 2! This is transmitted to the driving system as a steering wheel operating force, but this operating force (rotational force and direction of rotation) is detected by the n-drive sensor 11 attached to the input shaft 2, and is also input at the same time. The rotational speed is detected by the pickup 12 and inputted to the microcomputer 10 manually.

Since the optimum value corresponding to the input signal is preset in the storage unit 16, the input control unit 15 reads this value, performs predetermined signal waveform processing and amplification at the output interface 17, and then outputs the control valve. Enter 9.

Therefore, the control valve 9 is
The required plow pressure oil is sent into the oil chamber 8Δ or 8B of the power cylinder 3 in proportion to the size and direction of the oil chamber 3 (at this time, the other oil chamber 8A, 88G is connected to the tank T side).

) In this case, when the vehicle speed is low and the turning resistance of the wheels is large, the zero-drive sensor 11 detects that the torsion angle of the input shaft 2 is large, so the hydraulic pressure supplied to the power cylinder 3 is
When turning the handle or when the handle rotation speed is high, use this.
6 - The micro combi coater 10 controls the output value so that the switching amount of the control valve 9 increases so as to correspondingly increase the amount of pressure oil fed.

As a result, an operation to move the piston 4 using the input shaft 2 is performed in the oil chamber 8A or 8B corresponding to the operating load.
The steering wheel is assisted by hydraulic pressure, so the steering wheel can be operated easily and with an appropriate operating feel.

On the other hand, when the handle 1 is fixed, the reaction force that tries to twist the input shaft 2 according to the operating load decreases, so the output value of the load sensor 11 decreases, and the control valve 9 moves to the neutral position accordingly. is returned via the microcomputer 10, and the supply of pressure oil to the power cylinder 3 is thereby started.

In other words, you can also get feedback input at the same time.
When the input shaft 2 stops, the power cylinder 3 also stops operating, and the wheels are held at that switching angle.

By the way, with this power steering device, -7- PS Control Pulp 9 can be installed freely.
Because it was installed independently from other parts, the piping became long and a means of installation on the vehicle body was required.
There were actual equipment problems.

The present invention aims to solve these problems, namely, to simplify the piping and improve the ease of installation of PS control pulp.
At the same time, the aim is to achieve light phase reduction.

The present invention provides hydraulic piping that connects the pump and the control valve by fixing the valve housing of the electromagnetic PS control valve to the body of the hydraulic pump or the flow control valve body and interconnecting the hydraulic passages inside the housing. This is to reduce the time and effort required to install the control valve.

Hereinafter, embodiments will be described based on the drawings.

In FIGS. 2 and 3, 20 is a hydraulic cylinder 1 that supplies pressure oil to the power cylinder 3, and its discharge oil is
While the flow is controlled by the control valve 21, the oil is sent to the oil chamber 8A or 8B of the power cylinder 3 via the PS control pulp 22, and the returned oil is returned to the reservoir 23, and the oil is returned to the hydraulic pump 20
be sucked into.

The reservoir 23 is integrally attached to the upper part of the hydraulic pump 20, and the D-1 control valve 21 has a valve body 25 formed integrally with a part of the pump body 24 by casting or the like.

The housing 26 of the electromagnetic PST unit 1 to roll valve 22 controlled by the microcomputer 10 is
The valve body 25 is fixed to a hollow bolt 28 having a discharge passage 27 from the flow control valve 21 therein.

Further, a return vibe 31 of the reservoir 23 is inserted into a torsion passage 30 formed in the housing 26 and leading to the reservoir 23 through a seal 32 from the same axis as the hollow bolt 28 .

A valve spool 33 is slidably inserted into the valve housing 26, and a solenoid 35 to which a control output from the microcombination 1-10 is applied is connected to the end of the spool 33. Therefore, the valve spool 33 is displaced by the excitation of the solenoid 35, and the operating boat (passage) 37 or 38 connected to the oil chamber 8A or 8B of the power cylinder 3 is connected to the discharge passage 27.
The pump boat 36 is connected to the pump boat 36 or the tank boat 39 is connected to the return passage 30.

The hollow bolt 28 passes through the valve housing 26 from a direction perpendicular to the axis of the valve spool 33 and is screwed into the valve body 25. 27B, and communicate through an annular groove 40 on its outer periphery.

Seals 41 and 42 are fitted to the hollow bolt 28 on both sides of the annular W440.

Therefore, in this way, the PS control valve 2
2 to the valve body 25 of the flow control valve 21
By connecting the PSTIS control valve 22 with the hollow bolt 28, the PSTIS control valve 22 (1) is simplified, and the oil discharged from the flow control valve 21 is directly passed through the internal passage 36 of the valve housing 10-26 to the PS control pulp. 22, and at the same time, the return oil is returned to the reservoir 23 via the passage 30, so there is no need for piping to connect these.

Note that the PS control valve 22 is operated by the output of the microcomputer 10 in the same way as the control valve 9 in FIG. Obtaining steering force is the same as in Figure 1.

FIG. 4 shows a rack and binion power steering actuator.

In this case, said working boats 37 and 38 are connected to boats 44 and 45 of cylinder 43, respectively.

The rod 47 of the piston 46 inside the cylinder 43 has both protruding ends 47A and 47B connected to the φ-axis side, but a rack (not shown) is carved in the middle of the rod 47, and a rack (not shown) of the input shaft 2 (not shown) ) are meshed with each other.

Therefore, the piston 46 is moved to either side by the supply of hydraulic pressure -11- from the working boat 37,38.
The piston rod 47 is lowered and the direction of the wheel changes.

In this case, hydraulic assist may not be available when the hydraulic power source fails (
However, by rotating the input shaft 2, the rack can be displaced via the pinion, and the direction of the wheels can be changed.

In the above embodiment, the housing 26 of the PS control valve 22 is connected to the control valve body 25 by the hollow bolt 28, but the two may be integrally molded during casting, and the solenoid 35 may be of a proportional type or It is also possible to provide bush-pull types at two locations on both ends.

As described above, according to the present invention, the PS control valve is integrally connected or formed with the hydraulic pump body or the valve body of the flow control pulp, and the oil passage between the pulp body and the housing is communicated. Therefore, P
This simplifies the piping structure of the S control valve, eliminates the need for any brackets, etc. for its installation, and has the effect of simplifying the overall system.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the conventional @ position, Fig. 2 is a sectional view centered on the control pulp part, which is the main part of the present invention, Fig. 3 is a sectional view taken along line A-A, and Fig. 4 is a hydraulic pressure It is a sectional view showing other examples of an actuator. 2...Input shaft, 3...Power cylinder, 10...
Microcomputer, 11...Load cell, 12.
... Rotation speed pickup 20 ... Hydraulic pump, 21.
...Flow control pulp, 22...PS control pulp, 23...Reservoir, 24...Pump body, 25...Pulp body, 26...Pulp housing, 27...Discharge passage, 28... ...Hollow bolt, 30...Return passage, 31...Return pipe, 3
3...Pulp spool, 35...Solenoid, :1・-1-13-

Claims (1)

[Claims] A hydraulic actuator that operates in conjunction with an input shaft connected to the handle; a means for detecting the load transmitted to the input shaft and its rotational direction; and a microcomputer that calculates optimum steering values based on the detected values. In a power steering device equipped with an electromagnetic control valve that is switched by the output of a microcomputer to control hydraulic pressure from a hydraulic pump supplied to a hydraulic actuator, a pulp housing of the control valve is attached to a pump body of the hydraulic pump. A power steering device characterized by being integrally installed.