JPH0767910B2 - Hydraulic reaction type power steering - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic reaction type power steering used in an automobile.

BACKGROUND ART In this type of hydraulic reaction type power steering, when the vehicle is stationary, the steering force is maximized in proportion to the maximum pressure of the hydraulic pressure generated in the power cylinder. The handle got heavy.

Further, Japanese Patent Application Laid-Open No. 57-7762 discloses a power steering equipped with relief valves V ₁ and V ₂ that allow pressure oil to escape from the reaction force chambers R ₁ and R ₂ , and is disclosed in Japanese Patent Publication No. 45-8367. In the official gazette,
A reaction force control valve for a power steering system has been disclosed which allows pressure oil to escape from the reaction chambers A ', B'.

In the former, since the relief valve is built in the power piston, the set pressure of the relief valve cannot be adjusted after it is assembled in the power steering, and in the latter, the valve structure becomes complicated and accordingly The hydraulic circuit becomes complicated.

An object of the present invention is to make it possible to adjust a set pressure from the outside in a state where a relief valve for setting a hydraulic pressure fed back from a power cylinder to a control valve is incorporated in a power steering, so that a general automobile can be adjusted. When driving, steering force is normally fed back to the steering wheel,
When the vehicle is stationary, the steering force is reduced and the steering wheel is fed back to the steering wheel.
The purpose is to provide a hydraulic reaction type power steering that makes the steering wheel lighter.

SUMMARY OF THE INVENTION FOR PROBLEM: Claimed Invention Content In connection with the above-mentioned problems, the hydraulic reaction force type power
In steering, the control valve directionally controls the pressure oil flowing from the oil pump to the power cylinder, and guides the hydraulic pressure generated in the power cylinder in response to the steering force to the reaction chamber of the control valve. The steering wheel is steered by
A ball valve formed in the valve body of the valve to connect its reaction chamber to the oil reservoir side, and a relief valve for opening and closing the inlet, a pressure setting spring for pressing the ball valve against the inlet, and Assembled with a plug that is externally screw-operably exposed to allow adjustment of the set pressure of its pressure setting spring, and is located in its relief passage, and its relief valve is integrated into the power steering In that state, the set pressure can be adjusted from the outside, and when the vehicle is traveling normally, the relief valve is closed, the steering force is normally fed back to the steering wheel, and the vehicle is stationary. In that case, the relief valve is opened to allow high pressure oil to escape from the reaction chamber to the oil reservoir, and to operate it. Force is feet back on the handle been reduced, in that way, there is to be lightly the handle.

DESCRIPTION OF SPECIFIC EXAMPLES Specific examples of the hydraulic reaction force type power steering according to the present invention will be described with reference to the drawings.

The figure shows a tenth embodiment of the hydraulic reaction type power steering of the present invention applied to a truck.

The power steering 10 is manufactured as a linkage type that steers a pair of front wheels (not shown), and includes a knuckle arm (not shown), a drag link (not shown), and a link lever (not shown). , Compensating rod (not shown) Pitman arm (not shown),
Steering gear box (not shown), handle shaft (steering shaft not shown), handle (steering wheel not shown), pair of cylinder chambers 25, 26 Power cylinder 11, control valve 12 with reaction chamber 48,
An oil pump 13 connected to the control valve 12 by a supply hydraulic line 70, an oil reservoir 14 connected to the control valve 12 by a return hydraulic line 71,
A flow control valve 15 disposed in the supply-side hydraulic pipe 70 between the oil pump 13 and the control valve 12, and a reaction force chamber 48 of the control valve 12 in the oil reservoir 14 Is configured to include a relief valve 16 disposed in a passage 47 that communicates with, in particular, the relief valve 16 is closed when the truck is generally driven and when the truck is stationary. Is pressure set to open.

The power cylinder 11 is the control valve
A cylinder body 20 having a cylinder bore 21 incorporating 12 and opening oil ports 27, 28 connected to the cylinder ports 42, 43 of the control valve 12;
A piston 23 that is fitted in the cylinder bore 21 so as to be reciprocally slidable and that divides a pair of cylinder chambers 25, 26 corresponding to the oil ports 27, 28 into the cylinder bore 21. , A piston rod 24 that is fixed to the piston 23 and extends outwards in a rod cover (not shown) of the cylinder body 20 so that it can be inserted and removed, and the cylinder body 20 is The levers have their piston rods 24 rotatably connected to a chassis frame (not shown).

Also, the oil port 27 of the cylinder body 20
Is formed on the head cover 22 of the
Connected to the cylinder port 42 of the valve 12, while its oil port 28 is formed in its rod cover,
Then, it is connected to the cylinder port 43 of the control valve 12 through a bypass pipe 29.

In the power cylinder 11 having such a configuration, the movement of the piston 23 becomes the movement of the cylinder body 21 and the piston rod 24 to move the link lever, the drag link, and the knuckle arm. Is transmitted to a pair of front wheel shafts (not shown) vibratably connected to both ends of a front axle shaft (not shown), so that the power cylinder 11 is rotatable to the front wheel shafts. Steering the pair of supported front wheels.

The control valve 12 has a valve body 30 and
Hollow spool 31, spool shaft 32, a pair of reaction pistons 33, 34, and a pair of spool stoppers 35, 36
And a pair of reaction force piston stoppers 37 and 38, and a reaction force spring 39, which is a hydraulic reaction force type structure. The spool shaft 32 is pivotally connected to an input shaft (not shown), It is switched by the handle. Of course, the input shaft is connected to the compensating rod.

A valve bore 40 is formed in the valve body 30,
In the head cover 22 of the power cylinder 11,
A pump port 41, a pair of cylinder ports 42,43, a pair of tank ports 44,45, and a relief that are assembled to the cylinder body 20 and open into the valve bore 40 in place. -Has port 46.

And those pump port 41, cylinder port 4
2,43, link ports 44,45, and relief port 46
The openings in the inner peripheral surface of the valve bore 40 are cut into ring grooves.

In addition, the pump port 41 is connected to the supply side hydraulic pipe 70.
Connected to its oil pump 13, its cylinder port 42 connected to its oil port 27, its cylinder port 43 connected to its oil port 28 by its bypass pipe 29, its tank Ports 44, 45 are connected to their oil reservoir 14 by their return hydraulic line 71, and their relief port 46 is a relief passage
At 47, the tank ports 44, 45 were contacted.

The hollow spool 31 is reciprocally slidably disposed in the valve bore 40 formed in the valve body 30 to form a reaction chamber 48 inside, and the reaction chamber 48 is formed in the pump chamber. Communication port 49 on the pressure intake side that communicates with port 41
It is manufactured in a structure with.

Further, the hollow spool 31 has piston bores 51, 52 formed at both ends of the reaction force chamber 48, and a pump port 41 and tank ports 44, 45 formed in the valve body 30 thereof are provided in the cylinder. The ring grooves 53 and 54 forming the spool oil chambers that are switched and connected to the ports 42 and 43 are cut on the outer peripheral surface.

In addition, its hollow spool 31 has its valve body 30
The pressure relief side communication port 50 connecting the reaction force chamber 48 to the relief port 46 formed in the above is provided. Of course, the pressure relief side communication port 50 is machined into the ring groove 55 on the outer peripheral surface of the hollow spool 31, so that it can be maintained in the state always aligned with the relief port 46 of the valve body 30. There is.

The spool shaft 32 has one end penetrated into the hollow spool 31 and the spool 31 is inserted into the valve bore.
A pair of spools that are located at both ends of the spool 31 and fix the spool 31 so that the spool 31 slides back and forth.
Stoppers 35 and 36 are provided, and the other end is pivotally connected to the input shaft. That is, its spool shaft
32 is connected to its input shaft via a ball joint.

Furthermore, if the detailed fixing structure of the spool 31 is described,
The spool shaft 32 is positioned between the spool stoppers 35 and 36 and is fitted to one end of the spool shaft 32 by a sleeve-like spacer 56, and is screwed to one end of the spool shaft 32. Nut 57
The spool 31 is fixed by sandwiching the spool 31 between the spool stoppers 35 and 36 which are fixed to one end side by using.

The spool stoppers 35 and 36 are manufactured in a plate shape, and two small holes 58 are formed in the spool stoppers 35 and 36 at predetermined intervals on the stopper surface and are opened at predetermined positions. It has been done.

The pair of reaction force pistons 33, 34 are connected to the piston bore 5
1, 52 and a spacer 56 on the spool shaft 32 are reciprocally slidably fitted to close a reaction force chamber 48 formed inside the hollow spool 31.

The pair of reaction force piston stoppers 37, 38 is composed of two pins projecting from the surfaces of the head cover 22 and the shaft cover 59, which close the ends of the valve bore 40, respectively. , Its spool stopper 35,36
Through the small hole 58 of the spool, and strike the tip against the corresponding reaction force piston 33, 34, and then the piston bore 51, 5 of the spool 31.
The movement of the reaction force pistons 33 and 34 in 2 is restricted, and along with the movement of the spool shaft 32, the reaction force springs 39 cooperate to give a pumping action to the reaction force pistons 33 and 34. , Compresses the oil filled in the reaction force chamber 48, and changes the hydraulic reaction force that is fed back to the spool shaft 32.

The reaction spring 39 connects the spacer 56 on the spool shaft 32 between the reaction pistons 33, 34.
Is arranged around to provide pumping action to its reaction pistons 33, 34, and also for the neutral
It functions as a spring.

Further, in the control valve 12, the reaction force pistons 33, 34 and the piston bores 51, 52 in which the reaction force pistons 33, 34 are fitted so as to be capable of reciprocating sliding are made to have the same size, but Since the power cylinder 11 is manufactured as a single-sided rod-type double-acting cylinder, the reaction force pistons 33 and 34 are formed into a large diameter one and a small diameter one, and their piston bores 51 and 52 are also formed. Correspondingly, if it is formed with a large diameter bore and a small diameter bore, when the power steering 10 contracts, the driver feels heavy steering, and when the power steering 10 extends. It is possible to prevent the driver from feeling light steering, in other words, to make a difference between the left and right steering forces. That is, with such a simple change, it is possible to equalize the steering forces for right-turn and left-turn. Of course, if the power steering 10 is manufactured as an integral type, the control valve in that case is manufactured like the control valve 12.

The oil pump 13 is driven by a diesel engine (not shown) mounted on the truck and is connected to the pump port 41 of the control valve 12 to supply pressure oil to the power cylinder 11. It is arranged in the supply side pressure oil pipe 70 where the oil reservoir 14 is connected, sucks up and pressurizes the oil in the oil reservoir 14, and the discharge amount of the pressure oil that is almost proportional to the rotation speed of the diesel engine is It is made available. Of course, the oil pump 13 is manufactured in the same structure as the oil pump used in the existing power steering, and therefore the description of the structure will be omitted.

The flow control valve 15 is located in the supply hydraulic line 70 between the control valve 12 and the oil pump 13 and the control valve bypass 72 provides its return hydraulic line 71. Connected to.

This flow control valve 15 is
Pump port 61 connected to the discharge side of pump 13, control valve port 62 connected to pump port 41 of its control valve 12, and return connected to the suction side of its oil pump 13. ·port
Structure including a valve casing 60 having 63, and an oil return control spool (not shown) slidably disposed in a valve bore (not shown) of the valve casing 60 And its pump port
Adjust the flow rate of pressure oil sent to the 61 side, send a predetermined flow rate to the control valve port 62 side, and
Excess flow of pressure oil from its return port 63 to its oil reservoir 14 its control valve bypass
I am trying to return after 72. Of course, the flow control valve 15 is manufactured in the same structure as the flow control valve used for the existing power steering, so the description of the structure will be omitted. Ball to open and close port 65
Assembled with a valve 67, a pressure setting spring 68 that presses the ball valve 67 against the inlet port 65, and a plug 69 that is externally screw-operably exposed to allow adjustment of the set pressure of the pressure setting spring 68, Then, it is arranged in the relief passage 47 formed in the valve body 30 of the control valve 12 and connecting the reaction force chamber 48 to the oil reservoir 14 side. As such, the relief valve 16 is manufactured with a structure in which the valve body also serves as the valve body 30 of the control valve 12.

The relief valve 16 has an inlet port 65 formed in its valve body 30 and opened in its relief passage 47.
And a valve bore 64 with an outlet port 66, a ball valve 67 arranged in the valve bore 64 to open and close its inlet port 65, and a ball valve 67 arranged in the valve bore 64. Consists of a pressure setting spring 68 that presses against its inlet port 65, and a plug 69 that is screwed into its valve bore 64 to close the valve bore 64 and allow the set pressure of the pressure setting spring 68 to be adjusted. The reaction chamber 48 of the control valve 12
When the oil pressure rises above the set pressure, its inlet port 65, which was closed by its ball valve 67, is opened and pressure oil flows from its reaction chamber 48 to its tank port 45 via its relief passage 47. Further, the oil is stored in the oil reservoir 14 via the return side hydraulic pipe 71. That is, the relief valve 16 is a reaction force chamber of the control valve 12 when the truck is stationary.
It is opened only when the hydraulic pressure of 48 becomes high, that is, when it reaches a so-called preset relief pressure, allowing pressure oil to escape from its reaction force chamber 48 to its oil reservoir 14, suppressing the rise of hydraulic pressure, At the time of stationary steering, the hydraulic pressure generated in the power cylinder 11 becomes the maximum pressure, and in the power steering 10 having the control valve 12 that guides the hydraulic pressure to the reaction force chamber 48, The steering force is maximized in proportion to the maximum hydraulic pressure to prevent the steering wheel from becoming heavier, and it is closed when the truck is in general driving, and its power steering 10 normally operates the steering force. Pressure is set to occur.

Next, to explain the operation of the power steering 10 described above in correspondence with the running state of the truck, the diesel engine is operating, so the oil pump 13 is driven to・ The pressure oil discharged from the pump 13 is the flow control valve.
The flow rate is adjusted at 15, and a predetermined flow rate of the pressure oil flows through the supply side hydraulic pipe 70 and is sent to the pump port 41 of the control valve 12.

The pressure oil sent to the pump port 41 is returned from the tank port 44, 45 through the return hydraulic pipe 71 if the hollow spool 31 is in the neutral position as shown in the figure. Returned to its oil reservoir 14, its steering wheel is steered, its steering shaft, steering gear box,
Pitman arm, compensating rod,
And through the input shaft, the spool shaft 32 is pushed or pulled in either direction, the hollow spool 31 is slid in the direction of movement of the spool shaft 32, and in response to the movement of the hollow spool 31 The pressure oil is the cylinder
Power cylinder 11 from either port 42 or 43
Of the cylinder chamber 25, 26.

At the same time, since a part of the pressure oil sent to the pump port 41 is supplied to the reaction force chamber 48 via the pressure intake side communication port 49, the reaction force corresponding to the steering, so-called steering force. Is provided by the hydraulic and reaction force springs 39 in its reaction force chamber 48.

Now, if the truck is stationary, the pressure of the pressure oil supplied to the power cylinder 11 becomes the maximum pressure,
Along with this, a part of the pressure oil is supplied from the pressure intake side communication port 49 to the reaction force chamber 48, so that the pressure oil in the reaction force chamber 48 becomes higher than the relief pressure, and as a result, The relief valve 16 is opened, and a part of the pressure oil in the reaction force chamber 48 is transferred to the oil reservoir 14 via the pressure relief communication port 50, the relief port 46, the relief passage 47, and the return side pressure oil pipe 71. Missed.

In that way, the hydraulic pressure of the reaction chamber 48 is released,
The oil pressure in the reaction force chamber 48 is maintained at the relief pressure, and the increase in oil pressure is suppressed, and as a result, the increase in steering force is suppressed, that is, the steering force is reduced.

As such, when the truck is stationary, the hydraulic pressure generated in the power cylinder 11 becomes the maximum pressure, and the hydraulic pressure of the maximum pressure is guided to the reaction force chamber 48, but the hydraulic pressure is changed by the relief valve 16. Since it is escaped, the rise of the hydraulic pressure of the reaction force chamber 48 is suppressed, and the steering force becomes maximum in the power cylinder 11 in proportion to the maximum hydraulic pressure, but the control valve 12 Then, the maximum steering force is suppressed, in other words, the steering force foot-backed to the steering wheel is suppressed to the relief pressure, and as a result, the steering wheel is operated lightly.

Also, if the truck is traveling normally, the hydraulic pressure generated in the power cylinder 11 is lower than the relief pressure, so the hydraulic pressure in the reaction chamber 48 is the relief valve 16
This power steering 10 normally produces steering force without being missed by the present invention, as will be apparent from the specific embodiments of the invention described above with reference to the drawings. For those with ordinary knowledge in the field of technology,
The subject matter of this invention is readily embodied in alternative forms which are derived from the nature and substance of the invention and which are objectively admitted to incorporate them. Of course, the contents of the present invention are commensurate with the subject of the invention and are essential to the establishment of the invention.

Benefits of the Invention As can be understood from the above, the hydraulic reaction type power steering of the present invention has the
The relief passage is where the pressure oil flowing from the pump to the power cylinder is directionally controlled, and the hydraulic pressure generated in the power cylinder corresponding to the steering force is guided to the reaction chamber of the control valve for steering. A ball valve that is formed in the valve body of the control valve and connects its reaction chamber to the oil reservoir side, and a relief valve opens and closes the inlet, and a pressure setting spring that presses the ball valve against the inlet. , And a plug that is externally screw-operably exposed to allow adjustment of the set pressure of its pressure setting spring and is located in its relief passage, so that the hydraulic reaction power steering of this invention is Now, with the relief valve built into the power steering, the set pressure is externally adjusted. The power steering can be adjusted very easily, and when the vehicle is traveling normally, the hydraulic pressure generated in the power cylinder is low, the relief valve is closed, and the steering When force is normally fed back to the steering wheel and when the car is stationary, the hydraulic pressure generated in the power cylinder becomes the highest pressure, and the highest hydraulic pressure enters the reaction chamber. Even if guided, the relief valve is opened by the hydraulic pressure, the high hydraulic pressure is escaped from the reaction force chamber, the rise of the hydraulic pressure in the reaction force chamber is suppressed, and in the power cylinder, the hydraulic pressure reaches the maximum pressure. The steering force is maximized in proportion to, but the control valve suppresses the steering force fed back to the steering wheel to the relief pressure and feeds back to the bundle. The steering force is reduced, the steering wheel is lightly operated, and the driver's fatigue is alleviated. In addition, it is possible to manufacture without expensive means, and the complexity of the entire device is suppressed, As a result, it is very useful and practical for automobiles.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a specific example of the hydraulic reaction force type power steering of the present invention applied to a truck. 11 …… power cylinder, 12 …… control valve, 13 …… oil pump, 14 …… oil reservoir,
15 …… Flow control valve, 16 …… Relief valve.

Continuation of the front page (56) Reference JP-A-57-7762 (JP, A) JP-A-62-88663 (JP, A) JP-A-56-21971 (JP, A) JP-A-52-109231 (JP , A) JP 47-10860 (JP, A) JP 53-47636 (JP, A) JP 45-8368 (JP, A) JP 51-109628 (JP, A) 53-120036 (JP, U) Actually open 61-38275 (JP, U) Special public 45-8367 (JP, B1) Special public 49-39458 (JP, B1) Actual public 40-24323 (JP, Y1) Actual public Sho 49-38222 (JP, Y1)

Claims (1)

[Claims] 1. A control valve controls the direction of pressure oil flowing from an oil pump to a power cylinder, and hydraulic pressure generated in the power cylinder in response to a steering force is applied to a reaction force chamber of the control valve. In the case of steering by guiding to the
A ball valve formed in the body connects the reaction chamber to the oil reservoir side, and a relief valve has a ball valve that opens and closes the inlet, a pressure setting spring that presses the ball valve against the inlet, and an external screwdriver. A hydraulic reaction type power steering characterized by being operably exposed, assembled with a plug allowing adjustment of the set pressure of its pressure setting spring, and arranged in its relief passage.