JPH0260555B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering system used in a vehicle, and more particularly to a speed-sensitive power steering system equipped with a hydraulic reaction chamber.

In this type of power steering, the reaction force chamber is connected to the suction side of the oil pump, and a reaction force adjustment valve adjusts the amount of pressure oil released from the reaction force chamber to the suction side of the oil pump. The reaction force adjustment valve is also controlled to open and close by a control unit that changes the current flowing to the reaction force adjustment valve according to a signal from the vehicle speed sensor. As a result, in today's world where so many car types are manufactured, sold, and used, each control unit has a memory circuit for each car type. , a read-only memory ROM was required, and the manufacturing and data writing operations were complicated.

An object of the present invention is to write control data for a plurality of different vehicle types in advance in a read-only storage circuit, that is, a memory, provided in a control unit, and select and use the vehicle type control data from the memory according to the vehicle type. An object of the present invention is to provide a power steering system for use in a vehicle, which facilitates the memory fabrication and data writing operations.

With these issues in mind, the power steering used in the vehicle of this invention includes an oil pump,
The control valve includes a hydraulic reaction type control valve having a reaction force chamber, and a power cylinder to be steered, and a reaction force adjustment passage adjusts the reaction force chamber of the control valve to its oil.
communicating with the suction side of the pump, the reaction force regulating valve is arranged in the reaction force regulating passage so as to regulate the pressure in the reaction chamber of the control valve, and the control unit includes an input and an output circuit;
A read-only memory circuit ROM that includes writing of a plurality of different vehicle type control data, a vehicle control data selection circuit, an arithmetic circuit, and a control circuit that selects vehicle type control data in the memory circuit ROM corresponding to the vehicle type and makes it usable. is electrically connected to the vehicle speed sensor, and based on the selected vehicle type control data, calculates according to the input signal from the vehicle speed sensor, opens and closes the reaction force adjustment valve, and adjusts the reaction force in the reaction force chamber. It is configured to control the pressure.

Hereinafter, preferred specific examples of the power steering system used in a vehicle according to the present invention will be described with reference to the drawings.

Figures 1 and 2 schematically show an embodiment 10 of a power steering system for use in a vehicle according to the invention applied to a truck.

In order to steer the front wheels, the power steering 10 uses a speed-sensitive reaction force and is embodied in a linkage type, including a knuckle arm (not shown), a drag, and a link (not shown). , link lever (not shown), steering wheel (not shown), manual steering wheel
Gear box (not shown), Pitman arm (not shown), Compensating rod (not shown), Oil pump 11, Flow control valve 12, Control valve 1
3. A power cylinder 14, a reaction force adjustment passage 15, and a reaction force adjustment valve 16 disposed between the link lever and the compensating rod.
, a control unit 17 that drives and controls the reaction force regulating valve 16, and a vehicle speed sensor 18.

The oil pump 11 is driven by an internal combustion engine (not shown) mounted on the truck, is arranged in a hydraulic line 19 in the hydraulic circuit of the power cylinder 14, and is connected to an oil reservoir (not shown). The internal combustion engine is configured to suck up the oil in the internal combustion engine and obtain a discharge amount of pressure oil that is approximately proportional to the rotational speed of the internal combustion engine. Of course, the oil pump 11 is constructed similarly to the oil pump used in existing power steering systems, and a description of its construction will be omitted.

Flow control valve 12 is arranged in hydraulic piping 19, 20 in the hydraulic circuit of power cylinder 14.

The flow control valve 12 includes a pump port 21 connected to the discharge side of the oil pump 11, a control valve port 22 connected to the pressure port 32 side of the control valve 13, and a control valve port 22 connected to the pressure port 32 side of the control valve 13.・Pump 1
Suction port 2 connected to the suction side of 1
3 and an oil return control spool disposed so as to be able to slide back and forth within the casing, and adjust the flow rate of the pressure oil sent to the pump port 21 side, A predetermined flow rate is sent to the control valve port 22 side, and a surplus flow rate is returned to the suction side of the oil pump 11 from the suction port 23. Of course, the flow control valve 12 is the flow control valve 12 that has been used in existing power steering systems.
It is configured similarly to a control valve, so
A detailed explanation of its configuration will be omitted.

The control valve 13 is configured as a speed-sensitive type equipped with a reaction force chamber that changes the reaction force according to the vehicle speed, and is incorporated into the power cylinder 14, and is installed in the compensating rod, pitman arm, and manual steering. - The valve is operated by the steering wheel via the gear box, and in the hydraulic circuit of the power cylinder 14, it is arranged in the hydraulic piping 19, 20, and the oil is discharged from the oil pump 11, and the flow control valve The pressure oil whose flow rate is adjusted at 12 is supplied to the power cylinder 14, and the power cylinder 14 is
It returns the pressure oil worked in the cylinder 14 to the suction side of the oil pump 11, and has a valve body 24 and a control chamber with a reaction chamber 39 inside.
Valve spool 25, spool shaft 2
6, a pair of reaction plungers 27, 28, a pair of plunger stoppers 29, and a reaction spring 30.

The valve body 24 is assembled into the cylinder body of the power cylinder 14, and has a spool bore 31 formed therein.

The valve body 24 also includes a pressure port 32 opened to the spool bore 31, a pair of cylinder ports 33 and 34, and a pair of tank ports
The pressure port 32 is provided with ports 35, 36 and a reaction port 37, and the pressure port 32 is provided with the pressure oil whose flow rate is regulated by the flow control valve 12 to the cylinder chambers 54, 55 of the power cylinder 14. The cylinder ports 33 and 34 are connected to the supply side of the hydraulic piping 19, and the cylinder ports 33 and 34 are connected to the hydraulic piping 19.
Furthermore, on the cylinder side of 9 and 20, the tank
Ports 35 and 36 are connected to the hydraulic piping 20, respectively.

The control valve spool 25 forms a reaction chamber bore 38 that is open at both ends so as to form a reaction chamber 39 inside, and is disposed in the spool bore 31 so as to be able to reciprocate and slide.

Also, the control valve spool 2
5 has a large diameter plunger at one end of the reaction force chamber bore 38.
A small-diameter plunger bore 41 is formed at the other end of the bore 40 and the reaction force chamber bore 38, and a pressure communication port 42 that connects the reaction force chamber 39 to the pressure port 32, and a pressure communication port 42 that connects the reaction force chamber 39 to the reaction force port 37. It is provided with a reaction force release port 43 that communicates with the reaction force chamber 39.

Furthermore, the control valve spool 25 is provided with ring grooves 44, 45 forming a spool oil chamber for switchingly connecting the pressure port 32 to the cylinder ports 33, 34.

The spool shaft 26 has one end passed through the control valve spool 25, and
Moreover, the spool 25 is configured to slide back and forth within the spool bore 31.
A pair of spool stoppers 46 are provided at both ends of the spool 25 to fix the spool 25, and the other end is connected to a compensating rod.

Furthermore, to explain the fixing structure of the spool 25 in detail, the spool shaft 26 has a sleeve-shaped spacer fitted to one end side of the spool shaft 26 so as to be positioned between the spool stoppers 46. 47 and a nut 48 threaded to one end of the spool shaft 26.
Spool stopper 46 fixed to one end side of 6
The spool 25 is sandwiched between them and the spool 25 is fixed.

The spool stoppers 46 are formed in a plate shape, and have two small holes 49 opened in the stopper surface at predetermined positions and spaced apart from each other by a predetermined distance.

The reaction force plungers 27 and 28 are of large diameter,
The large diameter reaction plunger 27 is reciprocally slidably fitted into the large diameter plunger bore 40 and the spacer 47 on the spool shaft 26, and the small diameter reaction plunger 28 is formed with a small diameter. It is reciprocally slidably fitted into the small diameter plunger bore 41 and a spacer 47 on the spool shaft 26 to close a reaction chamber 39 formed within the control valve spool 25 thereof.

In this way, the reaction force plungers 27 and 28 are designed to have a large diameter and a small diameter.
In this power steering 10, when the power cylinder 14 retracts, the driver feels that the steering is heavy, and when the power cylinder extends, the driver feels
Since the steering feels soft, in other words, there is a difference in the left and right operating forces, so it is necessary to equalize the steering forces for right and left turns.

A pair of plunger stops 29 are provided on both inner end surfaces of the spool bore 31, respectively.
The pins pass through the small holes 49 of the spool stopper 46, abut their tips on the corresponding large-diameter and small-diameter reaction force plungers 27, 28, and extend toward the inner end surface of the spool bore 31. The movement of the reaction force plungers 27 and 28 is regulated, and as the spool shaft 26 moves, the reaction force spring 30 cooperates to give a pumping action to the reaction force plungers 27 and 28. The oil filled in the force chamber 39 is compressed to change the reaction force felt on the spool shaft 26.

The reaction spring 30 is disposed between the reaction plungers 27, 28 and around the spool shaft 26, i.e., the spacer 47, to impart a pumping action to the reaction plungers 27, 28, and to provide a pumping action to the reaction plungers 27, 28. In other words, it functions as a centering spring.

The power cylinder 14 includes a cylinder body 50 pivotally connected to a link lever, and a pair of cylinder chambers 54 and 55 formed within a cylinder bore 53 of the cylinder body 50.
It consists of a power piston 51 disposed in the cylinder bore 53 so as to be able to slide back and forth, and an operating rod 52 whose one end is fixed to the power piston 51 and the other end is pivotally connected to the chassis side. 57 is connected to hydraulic pipes 19 and 20, and is driven by pressure oil controlled by the control valve 13.

The reaction force adjustment passage 15 consists of a pipe that connects a reaction force port 37 formed in the valve body 24 of the control valve 13 to the hydraulic piping 20, and a reaction force relief port 43 is connected to the reaction force port 37. At this time, the pressure oil in the reaction force chamber 39 is released to the suction side of the oil pump 11, and the amount of oil released is also controlled by the reaction force adjustment valve 16.

The reaction force regulating valve 16 includes a valve body 58 having a spool chamber (not shown) and a pair of ports 60, 61 connected to the spool chamber, and a valve body 58 that slides reciprocally within the spool chamber. a spool (not shown) disposed such that the spool changes a passage cross-sectional area within its spool chamber in response to its reciprocating sliding; and an electric servo motor 59 for driving the spool; Depending on the speed, the spool is slid back and forth within the spool chamber, the passage cross-sectional area within the spool chamber is changed, and the flow rate of the pressure oil flowing between the ports 60 and 61 is adjusted;
It is configured to change the reaction force generated by the pressure oil in the reaction force chamber 39 of the control valve 13.

To be more specific, this reaction force adjustment valve 16 is designed to widen the cross-sectional area of the passage when the truck is traveling at low speed, and to narrow the cross-sectional area of the passage when the truck is traveling at high speed.
The servo motor 59 drives the spool. Of course, the servo motor 59 is controlled by the control unit 1 based on the signal from the vehicle speed sensor 18.
7.

The control unit 17 has an input side electrically connected to the vehicle speed sensor 18 and an output side electrically connected to the electric servo motor 59 of the reaction force regulating valve 16, and receives the signal from the vehicle speed sensor 18. an output signal to its servo motor 59 in response to
That is, it controls the output current and is mainly composed of an input and output circuit 62, a memory circuit 63, a central processing circuit 64, and a power supply circuit (not shown). It consists of a vehicle type control data selection circuit 66 and a control circuit 67, and is also provided with an address bus, a data bus, and a control line, as well as a storage circuit 63 and an interface circuit for external equipment.

The storage circuit 63 is a read-only memory.
In the ROM, in addition to the data necessary for the power steering 10, several different vehicle type control data, such as front engine, front
Drive-type passenger car, front engine, rear engine,
Vehicle type control data for drive-type passenger cars, two-axle trucks, three-axle trucks, buses, etc. is 68, 69,
70, 71, 72,... have been written. That is, it is stored.

Further, the vehicle type control data selection circuit 66 selects control data corresponding to the vehicle type from a plurality of vehicle type control data 68, 69, 70, 71, 72, . . . written in the storage circuit 63. It includes a selection signal generation circuit 73 equipped with a switch. Of course, the selection signal generation circuit 73 can also be configured to selectively connect the contacts of these switches with jumper wires on the board, and if configured in this way, the selection signal generation circuit 73 Circuit 73 becomes simpler.

The vehicle speed sensor 18 detects the traveling speed of the truck, and is disposed on the output shaft of a transmission mounted on the truck.

The vehicle speed sensor 18 is, of course, electrically connected to the input circuit 62 of the control unit 17 as described above, and sends a signal for controlling the opening and closing of the reaction force regulating valve 16 to the control unit 1.
Send to 7.

Next, to describe front wheel steering of the truck by the above-mentioned power steering 10 when the truck is running, first, for the control unit 17, in the selection signal generation circuit of the vehicle type control data selection circuit 66, The switch is operated to select usable vehicle type control data for the truck from among the vehicle type control data 68, 69, 70, 71, 72, . . . written in the memory circuit 63.

Thus, once the vehicle type control data for that truck has been selected, the control unit 17 receives a signal from the vehicle speed sensor 18 and provides an output signal to the electric servo motor 59 of the reaction force regulating valve 16. , ready to adapt to steering wheel operations.

Furthermore, the flow rate of pressurized oil from the oil pump 11 is adjusted by a flow control valve 12.
A predetermined flow rate is sent to the pressure port 32 of the control valve 13.

If the control valve spool 25 is placed in the neutral position, as shown in FIG. ，
36 to the suction side of the oil pump 11, but the steering wheel is steered and the manual steering box, pitman
If the spool shaft 26 is pushed or pulled in either direction via the arm, compensating rod, and the control valve spool 25 is slid in the direction of movement of the spool shaft 26, According to the movement of the control valve spool 25, the pressure oil is supplied to either one of the cylinder chambers 54, 55 of the power cylinder 14 and the reaction force chamber 39 via the cylinder side of the hydraulic piping 19, 20. .

The reaction force against the steering is given by the pressure in the reaction force chamber 39 adjusted by the reaction force adjustment valve 16 and the reaction force spring 30.

In such operation of the power steering 10, if the truck is driven at low speed,
The control unit 17 is the vehicle speed sensor 1
8, and the output signal, that is, the output current, which is compared and calculated based on the input signal, is sent to the electric servo motor 59 of the reaction force adjustment valve 16. is slid and the passage within the spool chamber is opened relatively wide.

Therefore, the pressure oil in the reaction force chamber 54 flows to the reaction force relief port 43 and the reaction force port 37, and further flows to the suction side of the oil pump 11 via the reaction force adjustment passage 15 and the hydraulic piping 31. , its reaction chamber 3
The pressure oil in the vehicle 9 does not provide a large resistance to the sliding of the reaction plunger 27 or 28, and steering during low-speed running is performed with a small operating force.

Of course, if the truck is steered when stopped, the traveling speed is zero and the passage of the reaction force regulating valve 16 is opened to the maximum, so the pressure in the reaction force chamber 39 is close to atmospheric pressure. This allows for cutting, width closing, turning back, etc. with a small amount of operating force.

Furthermore, if the truck is running at high speed, the control unit 17 inputs a signal from the vehicle speed sensor 18, and adjusts the reaction force by adjusting the output signal, that is, the output current, which is compared and calculated based on the input signal. Electric servo motor 59 of valve 16
Therefore, the spool is slid in the reaction force regulating valve 16, and the passage in the spool chamber is opened narrowly.

Therefore, the pressure oil in the reaction force chamber 39 becomes more difficult to return to the suction side of the oil pump 11 due to the throttling effect of the reaction force adjustment valve 16.
The pressure oil in the reaction force chamber 39 is transferred to the reaction force plunger 27.
Alternatively, there will be a large resistance to the sliding movement of 28, and as a result, steering during high-speed running is performed with a relatively large operating force. In this way, a relatively large operating force is required for steering during high-speed running, and running stability is improved.

Furthermore, when the truck is running at low speed, at high speed, or when the truck is stationary, the power steering 10 is operated as described above, and the reaction force plungers 27 and 28 are of a large diameter and a small diameter. Therefore, in the power steering 10, when the power cylinder performs a retracting operation and an extending operation, the difference between the right-hand turning operation force and the left-hand turning operation force becomes extremely small. In other words, Right-hand and left-hand steering forces are equalized. As a result, this power steering 1
0 relieves the driver from physical fatigue caused by truck steering.

According to the above invention, control data for a plurality of different vehicle types are written in advance in the read-only storage circuit, that is, the memory, provided in the control unit, and the control data for a plurality of different vehicle types are written in advance by the vehicle type control data selection circuit. Therefore, it becomes possible to select and use vehicle type control data from the memory, and it is not necessary to manufacture the memory for each car type and write the data, and as a result, the work of manufacturing the memory and writing the data is facilitated. This reduces manufacturing costs.

As mentioned above, from the specific examples of the present invention explained with reference to the drawings, it is difficult for those who have ordinary knowledge in the technical field to which the invention pertains to understand the following:
Various design modifications and changes can be easily made, and furthermore, it is possible that the content of this invention satisfies essentially the same problems and achieves the same effects as that invention. It may be readily replaced by embodiments that are essentially the same as the invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a specific example of the power steering system of the present invention, which is embodied as a linkage type and is applied to a truck, and FIG. 2 shows the power steering system shown in FIG. 1. FIG. 2 is a schematic diagram of the control unit used. 10...Power steering, 11...Oil pump, 12...Flow control valve, 13...Control valve, 14...
Power cylinder, 15...Reaction force adjustment passage, 16
... Reaction force adjustment valve, 17 ... Control unit, 18 ... Vehicle speed sensor.

Claims (1)

[Claims] 1. Hydraulic reaction type control system equipped with an oil pump, a flow control valve, and a reaction chamber.
In a steering device that includes a valve and a power cylinder, the reaction force adjustment passage connects the reaction force chamber of the control valve to the suction side of the oil pump, and the reaction force adjustment valve adjusts the reaction force of the control valve. The control unit is arranged in the reaction force adjustment passage to adjust the pressure of the chamber, and the control unit has input and output circuits, a read-only memory circuit ROM containing the writing of control data for a plurality of different vehicle types, corresponding to the vehicle type. It is electrically connected to the vehicle speed sensor, and is electrically connected to the vehicle speed sensor to select and use the vehicle type control data in the memory circuit ROM. A power steering system used in a vehicle is characterized in that the power steering system calculates based on the input signal from the vehicle speed sensor, opens and closes the reaction force adjustment valve, and controls the pressure in the reaction force chamber.