CN86107704A

CN86107704A - Static pressure steering for vehicle

Info

Publication number: CN86107704A
Application number: CN86107704.0A
Authority: CN
Inventors: 沃纳·蒂舍尔
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 1985-11-19
Filing date: 1986-11-14
Publication date: 1987-07-01
Also published as: DK161505C; DE3638487C2; DK525886A; DE3638487A1; DK161505B; CN1005401B; DK525886D0; SU1544180A3

Abstract

A kind of static pressure steering for vehicle, it is provided with a servopump (3), and the manual pump (5) that a direction of passage dish (6) is handled and one are assigned to the maneuvering valve (1) that turns to (11) two of oil cylinders to work and go in the loop as steering motor with pressure medium.Turn to oil cylinder (11) when center position, to be in blocked state.In the loop that turns to oil cylinder (11) high-pressure pipe (9,10), be provided with the safety device that a spring-loading relief valve device disturbs as moving traffic lane.Relief valve device has a safety valve (24) at least, in its high-pressure pipe (4) that unloads pressure side remittance servopump (3).

Description

Static pressure steering for vehicle

The present invention relates to a kind of static pressure steering of automobile, it has a servopump, and the manual pump that direction of passage dish is handled and one are assigned to the maneuvering valve that goes in two work of the oil cylinder loop that turns to as steering motor with pressure medium.Turn to oil cylinder when center position, to be in blocked state, at this moment be located at a spring-loading relief valve device conduct that turns in the oil cylinder pressure piping loop and prevent the safety device that moving traffic lane disturbs.

When the guiding valve of maneuvering valve when center position oil cylinder oil circuit is blocked, in some static pressure steerings, turn in the high-pressure pipe of each side of oil cylinder all need be provided with even stipulate safety valve will be set.Under the full operation pressure of adjusting, affix produces the manual steering force of difference of pressure in manual pump again, and pressure medium (adopting oil usually) is flowed out through relief valve device.Pressure medium unloads pressure side through safety valve and directly is discharged into fuel tank, or through the oil return pipe oil sump tank.Relief valve device generally includes two safety valves (turning to each piston chamber of oil cylinder to have), if they enter work, i.e. and draining, the sync break between bearing circle and wheel flutter so is because the oil cylinder that links to each other with wheel shaft is no longer followed the bearing circle motion.Under the normal circumstances, if bearing circle, thus manual pump has certain rotation, just makes the piston that turns in the oil cylinder that certain displacement is arranged, and then make wheel produce certain rotation.If moving traffic lane is passed to some bumps by the steering piston bar and turned to oil cylinder, the oil pressure that turns in the oil cylinder is raise, thereby in pipeline, cause corresponding compression shock.Because this moment, pressure medium must be discharged through safety-valve, thus asynchronism produced, that is do not turn on request.This makes wheel shaft or turns to and produces high load capacity on the oil cylinder, thereby may make wheel shaft part, tierod or deflecting bar bending, even fracture.Even these parts are provided with immediately and destroy, also can disturb the travel way of automobile, so that accelerate Tyte Wear.

In addition, also have a problem, promptly when the oil temperature was low, ducted resistance to flow was very big, and above-mentioned in this case shortcoming becomes even more serious.When the low situation of this oil temperature especially occurs in winter driving.

Because being installed in, more existing safety valves turn between oil cylinder high-pressure pipe and the tank drainback, so that their spring must be kept full pressure is poor.Size that thus must corresponding these safety valves of increase.

The objective of the invention is to make the static pressure steering that a kind of this paper begins described type, its necessary relief valve device is simplified greatly, and is safer, and the load of wheel shaft part is little.

The method that reaches this purpose by the present invention is to make relief valve device establish a safety-valve, and its pressure side of unloading is led to the servopump high-pressure pipe.

When maneuvering valve was in center position, the high-pressure pipe of servopump linked to each other through maneuvering valve and tank tube are logical.Therefore turn to the maximum pressure of only keeping in the high-pressure pipe of oil cylinder by the present invention leading to, because the resistance to flow of total system depends on the pressure side of unloading of safety valve fully by the spring force of safety valve.

By the present invention, when convertible valve was in steering position, it was servopump pressure that safety valve unloads pressure side, and this pressure is limited by the operational pressure limitations valve.If under this movable steering state, an effect of impact is arranged on wheel shaft from moving traffic lane, so unnecessary pressure medium will be through manual pump, and then imports oil return pipe through limiting valve.

Unload pressure side with this its of the present invention and import safety valve loop in the servopump high-pressure pipe, no matter convertible valve is in center position (turning to oil cylinder to stop up) or movable steering position, all can make the load that acts on the steering shaft keep identical level, nonsynchronous danger be arranged and can not flow through safety-valve owing to quantitative oil.

In design of the present invention, can in each root that turns to two high-pressure pipes of oil cylinder, adorn a check valve, their back side links to each other with the safety valve arrival end.The safety valve of a band spring need only be arranged in this case, thereby can reduce necessary structural volume, therefore correspondingly reduce the size of steering hardware.

Also can adopt different therewith another kind of schemes, at this moment establish a safety valve in turning to each root high-pressure pipe of oil cylinder, their public relief tube imports the servopump high-pressure pipe.

Though need two safety valves in this case, therefore can save two check valves.

Further specify the principle of work of the embodiment of the invention below by means of accompanying drawing, and further feature and advantage that they have are described.

Wherein:

The hydraulic circuit diagram of Fig. 1 static pressure steering of the present invention;

The local hydraulic circuit diagram of the static pressure steering of the another kind of structural shape of Fig. 2 the present invention.

Represented static pressure steering is the existing design form basically among the figure.It has a maneuvering valve 1 to be used to distribute oil stream, and oil is from fuel tank 2s process servopump 3 and high-pressure pipe 4.The mobile of maneuvering valve 1 realizes that by manual pump 5 manual pump is by bearing circle 6 manipulation work.Manual pump links to each other with maneuvering valve 1 with 8 by handling pipeline 7.

Two high-

pressure pipes

9 and 10 are from maneuvering valve 1, lead to one and turn to oil cylinder 11 as steering motor.The piston rod 12 of hydraulic actuating cylinder 11 pistons 13 links with the mechanics of wheel shaft (not shown).

From maneuvering valve 1, there is an oil return pipe 14 to lead to fuel tank 2.By common mode two inlet valves 15 are housed between two high-

pressure pipes

9 and 10, their purpose is the

piston chamber

16 and 17 that turns to oil cylinder 11 to be full of constantly the space do not occur.There is an oil inlet 18 to lead to fuel tank between two inlet valves.Adorned an existing operational pressure limitations valve 19 between oil inlet 18 or oil return pipe 14 and the high-pressure pipe 4, it generally works when steering position.In addition, be typically provided with an inlet valve 20 between oil return pipe 14 or oil inlet 18 and maneuvering valve 1, its assurance manual steering can reliably be carried out when servopump 3 breaks down.

Have two

check valves

21 and 22 to be used for passing and come up from the presumable bump in steering shaft aspect, these bumps cause piston 13 displacements, thus and generation compression shock.These two check valves are installed between high-

pressure pipe

9 and 10 relatively, open when making it produce compression shock in relevant with it high-pressure pipe.Pick out a public relief tube 23 at the back side of these two

check valves

21 and 22, the safety valve 24 of a band spring 25 is housed in the pipe.When this safety valve 24 is installed, when being opened at the pressure that has overcome spring 25, it unloads pressure side towards high-pressure pipe 4 in relief tube 23.

In the steering hardware loop, also a shutoff valve 26 and a pressure-relief valve 26a have been adorned by common mode.

The service condition of static pressure steering of the present invention is as follows:

Maneuvering valve, 1 when center position, only exists the low pressure that makes oil flow in the system.This means, as one from the bump of wheel shaft aspect with when producing pressure medium flow thus, unnecessary pressure medium can (according to the direction of bump) through high-

pressure pipe

9 or 10,

check valve

21 or 22 and safety valve 24 enter high-pressure pipe 4, pressure medium can flow out through maneuvering valve 1 more therefrom.

When being in steering position, maneuvering valve 1 equally also need not to overcome special difference of pressure.At this moment, unnecessary pressure medium can be through manual pump 5 with through

handling pipeline

7 or 8 and maneuvering valve 1,

pipeline

27 and 28 and right-hand in the drawings pressure-relief valve 26a of expression, enter high-pressure pipe 4, can enter in the fuel tank 2 equally through operational pressure limitations valve 19 therefrom again.

Obviously, the spring 25 of safety valve 24 can design very softly.Its design parameters can for example be 150 crust.Therefore when at the steering position operation pressure being 150 crust, obtained a for example safety device of 150 crust.If in pressing prior art constructions, this safety valve but must be kept the pressure of about 200 crust, because for fear of asynchronism, this safety valve must exceed operation pressure 50 crust at least.

Fig. 2 has represented another kind of structural shape of the present invention, has only represented the key component of loop diagram bottom for the sake of simplicity among the figure.

As seen from the figure, be provided with two in this case respectively with safety valve 24A and the 24B of spring 25A and 25B.The relief tube 23 that flows back to high-pressure pipe 4 also is to draw from two safety valve 24A that install relatively and the pressure side of unloading of 24B.

In this case, though, saved two check valves but then because be provided with two

safety valve

24A and 24B makes some increase of scantling of structure.

Claims

1, automobile static pressure steering, it has a servopump, and the manual pump that direction of passage dish is handled and one are assigned to the maneuvering valve that goes in two work of the oil cylinder loop that turns to as steering motor with pressure medium.Turn to oil cylinder when center position, to be in blocked state, at this moment be located at the safety device that a spring-loading relief valve device turning in the oil cylinder pressure piping loop disturbs as moving traffic lane, it is characterized by: relief valve device has a safety valve (24) at least, its high-pressure pipe (4) that unloads pressure side remittance servopump (3).

2, by the described static pressure steering of claim 1, it is characterized by: impact in order to pass away pressure medium, between high-pressure pipe (4), servopump (3) and fuel tank (2), an operational pressure limitations valve (19) is housed.

3, by claim 1 or 2 described static pressure steerings, it is characterized by: a check valve (21,22) all is housed turning on each root high-pressure pipe (9,10) of oil cylinder (11), its back side links to each other with the arrival end of safety valve (24).

4, by claim 1,2 or 3 described static pressure steerings, it is characterized by: turn to each root high-pressure pipe (9,10) of oil cylinder (11) to be provided with a safety valve (24A and 24B), their public relief tube (23) imports in the high-pressure pipe (4) of servopump (3).