Subaru of Legasi, Autbek
+ Cars Subaru Legacy, Outback
+ Operation manual
+ Routine maintenance
+ Cooling systems, heating
+ Power supply system and release
+ Electric equipment of the engine
+ Manual box and differential
+ Automatic transmission
+ Brake system
- Suspension bracket and steering
+ Forward suspension bracket
+ Back suspension bracket
Design and the principle of functioning of elements of the hydrostrengthened steering drive - the general information
Adjustable safety steering column - the general information
Removal and installation of a steering wheel
Removal, check of a state and installation of the cardan hinge of a steering column
Removal, service and installation of a steering column
Removal, service and installation of the steering mechanism
Removal, installation and check of a condition of elements of a hydraulic path of GUR
Removal, service and installation of the steering pump
Removal and installation of the tank of GUR liquid
Check and replacement of GUR liquid, removal of air from a hydraulic path
+ Wheel assemblies, suspension bracket geometry
+ Onboard electric equipment
Design and the principle of functioning of elements of the hydrostrengthened steering drive - the general information
Function chart of system of GUR on l models 2.0 and 2.5
Function chart of system of GUR on models of 3.0 l
Organization of hydrostrengthening of the steering mechanism
The drive of the steering pump is carried out directly from the engine by means of a driving belt.
At the rectilinear movement of the car the valve switch of pump assembly, sensitive to changes of pressure, remains open, providing dumping of hydraulic liquid back in the tank of system of GUR.
The function chart of hydraulic system of strengthening of the steering drive is presented on illustrations.
Due to use of the valve of adjustment of an expense pressure of hydraulic liquid is supported almost constant at any turns of the engine. Under an adjustable pressure hydraulic liquid moves on a hose And to the rotor operating valve.
When turning a steering wheel the rotor valve connected to shaft of the leading gear wheel opens a hydraulic contour in the direction corresponding to the direction of turn travel about hydraulic liquid on a tube And or In moves in corresponding (And or In) a working chamber.
Increase of pressure in a working chamber leads to emergence of the auxiliary effort influencing the piston of a steering rack in the direction of movement of the last that in an essential measure reduces resistance of a steering wheel to rotation.
Shift of a lath leads to replacement of hydraulic liquid from the second working chamber in the GUR tank through tube A/V, the rotor valve and a hose of Century.
Restriction of the maximum pressure of hydraulic liquid is carried out due to inclusion in pump assembly of the reducing valve.
As the steering shaft via the rotor operating valve mechanically connects to shaft of the leading gear wheel, loss of management does not happen even in case of refusal systems of hydrostrengthening.
Design and principle of functioning of the steering mechanism
The basis of hydraulic part of the steering mechanism is made united in the general assembly by the rotor operating valve and the power cylinder of rack transfer. The rod of a steering rack in the used design plays a piston role in the power cylinder, through the rotor valve the shaft of the leading gear wheel is passed. Working chambers of the cylinder and the rotor valve are connected among themselves by means of two hydraulic tubes.
The rotor operating valve
Design of the rotor managing director of the valve
The scheme of functioning of the rotor valve at the released steering wheel
The scheme of functioning of the rotor valve at rotation of a steering wheel to the right
Scheme of connection of the steering pump (l models 2.0 and 2.5)
Scheme of functioning of the steering pump (l models 2.0 and 2.5)
Design of the shiberny pump (l models 2.0 and 2.5)
Principle of functioning of the valve of management of an expense (l models 2.0 and 2.5)
Scheme of connection of the valve pressure, sensitive to change (l models 2.0 and 2.5)
The scheme of functioning of the valve pressure, sensitive to change, at the released steering wheel (l models 2.0 and 2.5)
The scheme of functioning of the valve pressure, sensitive to change, at rotation of a steering wheel (l models 2.0 and 2.5)
Principle of functioning of the reducing valve of the pump GUR (l models 2.0 and 2.5)
The operating valve consists of the rotor rotating together with a steering in bulk, the leading gear wheel entered into gearing with a rotor by means of the torsion core and rotating together with a coupling gear wheel. The design of the valve is presented on an illustration.
The flutes of C and D forming channels through passage from V1 on V4 for a stream of hydraulic liquid are provided in a rotor and the coupling of valvate assembly.
The configuration of a gap of gearing of a gear wheel with a rotor provides possibility of the manual drive of a lath in case of refusal of system of hydrostrengthening.
When the torsion core is twisted under the influence of the torque enclosed to a steering wheel, the provision of a rotor concerning the coupling changes that is followed by change of the section through passage of V1 ÷ V4 channels. This mechanism allows to correlate a pressure of a working body of system to the size of the effort enclosed to a steering wheel.
When the steering wheel is released a rotor and the coupling keep in neutral situation, in the carburetor the V1, V2 and V3 channels formed by flutes of C and D keep identical sections through passage. Thus the stream of the liquid forced by the pump will be redirected back in the GUR tank, and the steering rack remains in a free state.
Turning of a steering wheel leads to the right to a priotkryvaniye of V1 and V3 channels while V2 and V4 channels are almost completely blocked. Thus pressure in the camera A of the power cylinder increases in proportion to decrease in a consumption of hydraulic liquid via V2 and V4 channels, on the other hand, pressure in the camera B decreases due to removal of liquid in the GUR tank on the V3 channel. the arising difference of pressure from the different parties of the piston leads to shift of a lath in the demanded direction (to the right). At rotation of a steering wheel to the left the picture changes specularly that leads to shift of a steering rack in the demanded direction.
Violation of serviceability of functioning of system of hydrostrengthening (for example, as a result of break of a driving belt) leads to refusal of increase of hydraulic pressure therefore the torque enclosed to a steering wheel starts being transferred mechanically from a rotor of the managing director of the valve directly to the leading gear wheel of the steering mechanism.
Design and principle of functioning of the steering pump
The drive of the shiberny steering pump is carried out from the engine by means of a wedge-shaped belt.
The tank of hydraulic liquid is installed on a body element of the car.
L models 2.0 and 2.5
The scheme of connection of the pump GUR to the steering mechanism is shown on an illustration.
The structure of the pump switched on three valves: valve of management of a liquid consumption and also sensitive to change of pressure and reducing valves.
The valve of management of a consumption of working liquid provides maintenance of a consumption of hydraulic liquid at the identical level regardless of engine turns.
The valve, sensitive to change of pressure, provides return of liquid to the GUR tank at the released steering wheel.
The reducing valve serves for protection of system against excessive increase of pressure, a cut could result, for example, from turning of a steering wheel at all length of the course of its rotation.
The basis of pump assembly is made placed in an eccentric ring by the rotor equipped with ten sliding blades (shiber). At rotation of a rotor freely put shiberny shovels under the influence of centrifugal force seek to move forward from the directing grooves in the radial direction, nestling thus on walls of the eccentric chamber having an oval form. The liquid which is soaked up through inlet ports in space between shovels in process of reduction of volume of a cavity compresses and under a pressure is pushed out through final ports to the working highway of system of hydrostrengthening.
The valve of management of a consumption of liquid consists of the cylindrical zolotnik which is wrung out to the right in process of increase of pressure of working liquid owing to increase in turns of the engine, - such push-up of a zolotnik is followed by narrowing of the section through passage of a throttle opening and, as a result, to reduction of a consumption of liquid.
The left end of pressure of the valve, sensitive to change, it is open towards release of the pump, and right it is connected to an exit of the valve of management of an expense.
At the released steering wheel the working liquid passed via the valve of management of an expense towards the power cylinder of the steering mechanism will be redirected in the GUR tank bypassing the rotor managing director of the valve that does not allow to raise to pressure on the right side of valvate assembly. Excess of pressure forced by the pump on the left side of the valve concerning pressure leads to shift of a zolotnik of the valve to the right and, as a result, to opening of the drain port locked by a zolotnik and the redirection to the liquid forced by the pump in the GUR tank and to the corresponding pressure decrease in pump assembly on the right.
Rotation of a steering wheel in any direction leads to increase in pressure of the management of an expense missed via the valve to the piston of a steering rack of a stream of liquid. Thus the zolotnik of the valve pressure, sensitive to change, continues to be kept by the pressure of the liquid forced by the pump which is wrung out to the right for some time. At some point, when pressure on the left side of valvate assembly reaches critical value, the zolotnik is wrung out to the left, blocking drain port. As a result pressure in pump assembly increases that provides adequate increase of a pressure in a working chamber of the steering mechanism.
Basic element of the reducing valve is the control ball which is propped up by a spring. From the party opposite to a spring on a ball pressure developed by the expense passed via the valve of management and the liquid stream given to the steering mechanism makes impact. Excessive increase of hydraulic pressure leads to compression of a spring and push-up of a ball to the left therefore the drain channel created in a body of valvate assembly is slightly opened and excess of liquid is dumped in the GUR tank.
Models of 3.0 l
The scheme of functioning of the steering pump on models 3. 0 l it is shown on an illustration.
Design of the shiberny pump (model of 3.0 l)
The scheme of functioning of the pump of variable productivity at small turns of the engine
The scheme of functioning of the pump of variable productivity at averages and high turns of the engine
The scheme of operation of the reducing valve of the pump of variable productivity sharp increase of working pressure in a hydraulic path of the steering amplifier
The consumption of hydraulic liquid in system of hydrostrengthening of a wheel of models of 3.0 l is regulated according to change of turns of the engine that guarantees the adequate resistance of a steering wheel to rotation at high speeds of the movement. The pump of variable productivity changes the account characteristic thanks to adjustment to a form of an eccentric chamber depending on engine turns. Nature of dependence is given in an illustration.
The basis of a design of pump assembly is made by the shiberny pump of variable productivity providing decrease in quantity of the system which is pushed out to the working highway for one turn of a rotor of hydraulic liquid at increase in turns of the engine. Pump assembly switched also on the managing director and reducing valves.
The design of the shiberny pump is presented on an illustration. The main distinctive feature of this design is mobile installation of an eccentric ring which can be displaced concerning a rotor. Such decision allows to carry out adjustment of productivity of the pump on one turn of a rotor.
The principle of functioning of the steering pump of variable productivity at small turns of the engine (sector In a curve on an illustration)
Owing to design features, the liquid forced by the pump moves on the operating valve along with two parties. Thus on the left side of valvate assembly liquid moves from unregulated final port of the pump while before giving on the right side of the valve it is passed previously through a throttle opening, providing a certain decrease in a pressure. Thus, pressure on the left side of the operating valve is always a little higher, than from the right.
During the work on low turns the pump is provided by a low pressure and the resulting difference of pressure from the different parties of the valve is small. Thus the valve under the influence of the effort developed by the spring remains wrung out to the left, and the liquid which is under atmospheric pressure from the GUR tank comes to the camera A of an external cavity of pump assembly. On the other hand, In liquid is in a chamber under pressure determined by resistance of a throttle opening of adjustable final port. As a result, the eccentric ring which is in addition drawn in on the right by a spring remains wrung out to the left and eccentricity of a rotor chamber (and, therefore, and pump productivity) is supported maximum.
The principle of functioning of the steering pump of variable productivity at averages and high turns of the engine (curve V-D sector on an illustration)
At averages and high turns of the engine productivity of the pump increases. Increase of pressure before a throttle opening brings to push-up of the managing director of the valve to the right and supply of liquid from unregulated final port of the pump into the camera A after a preliminary drosselirovaniye in the left inlet port of valvate assembly. The camera B at removal of the managing director of the valve connects to the GUR tank to the right. As a result of adjustable increase of pressure in the camera A push-up of an eccentric ring to the right at the demanded size with overcoming of the counteraction developed by a spring is provided. Shift of a ring leads to decrease in eccentricity to a rotor chamber and the corresponding reduction of productivity of the pump.
Degree of a priotkryvaniye of the operating valve is defined by a difference of pressure ahead of and behind a throttle opening of working final port of pump assembly.
The principle of operation of the reducing valve of the steering pump at sharp increases of working pressure in system of GUR
When as a result of a reversing of a steering wheel the hydraulic contour of the steering mechanism is blocked, pressure in it can increase very much considerably. On reaching working pressure in system of a certain value there is a push-up of a control ball of the reducing valve which is built in directly in a zolotnik of the operating valve. As a result of opening of the channel connecting a rotor chamber to the GUR tank dumping of excessive 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)
On the Outback models the steering mechanism with the variable transfer relation is used. At the rectilinear provision of the operated wheels the transfer relation of rack assembly is maintained equal 1:19 that provides high course stability of the car at high speeds of the movement. At the maximum reversing of a steering wheel to the right or to the left the transfer relation decreases, providing higher sensitivity of the steering drive.