Subaru Legacy/Outback

1999-2003 of release

Repair and car operation

Steering

Design and principle of functioning of elements of the hydrostrengthened steering drive - the general information

The rotornyj operating valve

Design роторного the operating valve

The operating valve consists of a rotor rotating together with steering shaft, the leading gear wheel entered into gearing with a rotor by means of торсионного of a core and rotating together with a gear wheel муфты. The valve design is presented on an illustration.

In a rotor and муфте клапанной assemblages are provided flutes With and D, forming channels through passage with V1 on V4 for a stream of a hydraulic liquid.

The configuration of a backlash of gearing of a gear wheel with a rotor provides possibility of a manual drive рейки in default hydrostrengthening systems.

When торсионный the core is braided under the influence of a twisting moment put to a steering wheel, rotor position rather муфты changes that is accompanied by change of section of channels V1 ч V4 through passage. The given mechanism allows to correlate a pressure of a working body of system to size of the effort put to a steering wheel.

When the steering wheel is released a rotor and муфта channels V1, V2 and V3 are kept in neutral position, in the carburettor, formed by flutes With and D keep identical sections through passage. Thus the stream of a liquid forced by the pump перенаправляется back in tank GUR, and steering рейка remains in a free condition.

Поворачивание a steering wheel to the right leads приоткрыванию channels V1 and V3 while channels V2 and V4 are almost completely blocked. Thus pressure in the chamber And the power cylinder raises proportionally to decrease in the expense of a hydraulic liquid through channels V2 and V4, on the other hand, pressure in the chamber In decreases at the expense of liquid tap in tank GUR on channel V3. Arising difference of pressure from the different parties of the piston leads to displacement рейки in a demanded direction (to the right). At steering wheel rotation to the left the picture changes mirror that the helmsman рейки in a demanded direction leads to displacement.

Infringement of serviceability of functioning of system of hydrostrengthening (for example, as a result of breakage drive a belt) leads to refusal of increase of hydraulic pressure therefore the twisting moment put to a steering wheel starts to be transferred mechanically from a rotor of the operating valve directly to a leading gear wheel of the steering mechanism.

Design and principle of functioning of the steering pump

The drive шиберного the steering pump is carried out from the engine by means of клиновидного a belt.

The tank of a hydraulic liquid is established on кузовном a car element.

Models 2.0 and 2.5 l

The scheme of connection of pump GUR to the steering mechanism is shown on an illustration.

Three valves are included in pump structure: the valve of management of the liquid expense, and also sensitive to change of pressure and редукционный valves.

The valve of management provides with the expense of a working liquid maintenance of the expense of a hydraulic liquid at identical level without dependence from engine turns.

Sensitive to change of pressure the valve provides return of a liquid to tank GUR at the released steering wheel.

The reduktsionnyj valve serves for protection of system against excessive increase of pressure, a cut could occur, for example, as a result поворачивания a steering wheel for all length of a course of its rotation.

Basis of pump assemblage makes placed inside эксцентрикового rings equipped with ten sliding blades (шиберами) a rotor. At rotor rotation freely посажанные шиберные shovels under the influence of centrifugal force aspire to be put forward from the directing grooves in a radial direction, nestling thus on walls having the oval form эксцентриковой chambers. Soaked up through inlet ports in space between shovels the liquid in process of reduction of volume of a cavity is compressed and under a pressure is pushed out through final ports in a working path of system of hydrostrengthening.

The valve of management of the liquid expense consists of the cylindrical zolotnik which is wrung out to the right in process of increase of pressure of a working liquid owing to increase of turns of the engine, - such отжимание a zolotnik is accompanied by narrowing of section of a throttle aperture through passage and, as consequence, to reduction of the expense of a liquid.

The left end of pressure of the valve sensitive to change it is opened towards pump release, and right it is connected to an exit of the valve of management of the expense.

At the released steering wheel passed through the valve of management of the expense towards the power cylinder of the steering mechanism a working liquid перенаправляется in tank GUR around роторного the operating valve that does not allow to raise to pressure on the right side клапанной assemblages. Excess of pressure forced by the pump on the left side of the valve concerning pressure on the right leads to displacement of a zolotnik of the valve to the right and, as consequence, to opening of drain port locked by a zolotnik and a redirection of a liquid forced by the pump in tank GUR and to corresponding pressure decrease in pump assemblage.

Steering wheel rotation in any direction leads to increase in pressure of management passed through the valve the expense to the piston the helmsman рейки a liquid stream. Thus the zolotnik of pressure of the valve sensitive to change during some time continues to be kept by the pressure of a liquid forced by the pump wrung out to the right. At a given time, when pressure on the left side клапанной reaches assemblages of critical value, the zolotnik is wrung out to the left, blocking drain port. As a result pressure in pump assemblage raises that provides adequate increase of a pressure in the working chamber of the steering mechanism.

Basic element редукционного the valve is the control ball propped up by a spring. From the party opposite to a spring the ball is affected by the pressure developed passed through valve of management by the expense and a stream submitted to the steering mechanism of a liquid. Excessive increase of hydraulic pressure leads to compression of a spring and отжиманию a ball to the left therefore the drain channel and surplus of a liquid is slightly opened generated in a body клапанной assemblages is dumped in tank GUR.

L models 3.0

The scheme of functioning of the steering pump on models 3. 0 l it is shown on an illustration.

The expense of a hydraulic liquid in system of hydrostrengthening of a wheel of models 3.0 of l is regulated according to change of turns of the engine that guarantees adequate resistance of a steering wheel to rotation at high speeds of movement.

Basis of a design of pump assemblage makes шиберный the pump of variable productivity providing decrease of quantity of system pushed out in a working path for one turn of a rotor of a hydraulic liquid at increase of turns of the engine. In pump assemblage also are included the managing director and редукционный valves.

The design шиберного the pump is presented on an illustration. The main distinctive feature of the given design is mobile installation эксцентрикового rings which can be displaced concerning a rotor. Such decision allows to carry out updating of productivity of the pump on one turn of a rotor.

Principle of functioning of the steering pump of variable productivity at small turns of the engine (sector А-В of a curve on an illustration)

Owing to the design features, the liquid forced by the pump moves on the operating valve simultaneously from two parties. Thus on a left-hand side клапанной assemblages the liquid moves from noncontrollable final port of the pump while before giving on the right party of the valve it is preliminary passed through the throttle aperture, providing certain decrease in a pressure. Thus, pressure on the left side of the operating valve always is a little above, than from the right.

At work on low turns the pump is provided with a low pressure and a resultant a difference of pressure from the different parties of the valve is insignificant. Thus the valve under the influence of the effort developed by the spring, remains wrung out to the left, and in the chamber And an external cavity of pump assemblage the liquid being under atmospheric pressure from tank GUR arrives. On the other hand, in the chamber In a liquid is under the pressure defined by resistance of a throttle aperture of adjustable final port. As a result, in addition drawn in on the right a spring эксцентриковое a ring remains wrung out to the left and эксцентриситет роторной chambers (and, hence, and productivity of the pump) is supported by the maximum.

Principle of functioning of the steering pump of variable productivity at average and high turns of the engine (sector В-D of a curve on an illustration)

At average and high turns of the engine productivity of the pump increases. Pressure increase before a throttle aperture results отжиманию the operating valve to the right and giving of a liquid from noncontrollable final port of the pump in the chamber And after preliminary дросселирования in the left inlet port клапанной assemblages. The chamber In at displacement of the operating valve to the right incorporates to tank GUR. As a result of adjustable increase of pressure in the chamber And it is provided отжимание эксцентрикового rings to the right on the demanded size with overcoming of counteraction developed by a spring. Ring displacement leads to decrease эксцентриситета роторной to the chamber and corresponding reduction of productivity of the pump.

Operation principle редукционного the valve of the steering pump at sharp increases of working pressure in system GUR

When as a result of a steering wheel reversing the hydraulic contour of the steering mechanism is blocked, pressure in it can raise very considerably. On reaching working pressure in system of certain value occurs отжимание a control ball редукционного the valve which has been built in directly in a zolotnik of the operating valve. As a result of opening of the channel connecting роторную the chamber with tank GUR, dump of superfluous pressure and maintenance of the pressure head characteristic of the pump at the set level is provided.

The steering mechanism with the variable transfer relation (VGR)