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GB2069429A - A hydraulic steering apparatus - Google Patents

A hydraulic steering apparatus Download PDF

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Publication number
GB2069429A
GB2069429A GB8103945A GB8103945A GB2069429A GB 2069429 A GB2069429 A GB 2069429A GB 8103945 A GB8103945 A GB 8103945A GB 8103945 A GB8103945 A GB 8103945A GB 2069429 A GB2069429 A GB 2069429A
Authority
GB
United Kingdom
Prior art keywords
steering
electric motor
pressure
pump
steering wheel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB8103945A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of GB2069429A publication Critical patent/GB2069429A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
    • B62D5/065—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
  • Servomotors (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)

Abstract

The steering apparatus has a hydraulic pump (11) which is driven by an electric motor (10). The latter is only switched in when a steering operation takes place at the steering wheel (21) and indeed through an electrical switch (23) which is formed as a torque switch or as a tilt switch. The pump (11) then delivers pressure medium through a multi-way valve, likewise actuated from the steering wheel to the steering cylinder. <IMAGE>

Description

SPECIFICATION A hydraulic steering apparatus State of the Art The invention originates from a hydraulic steering apparatus according to the preamble to the main claim. One known steering apparatus of that kind has the disadvantage that the pump is continually driven, that is to say even when not steering. For this reason, unnecessary energy is used up.
Furthermore, a steering apparatus is known in which the pump is only switched in when steering and a particular switching pressure is reached in the hydraulic system. Then the electric motor is switched in by a pressure switch. That has the advantage that less energy is required but also has the disadvantage that not only must the said switching pressure be applied but when using the servo assistance a torque jump occurs whereby an accurate steering is impaired. Moreover, the switching in dynamics are bad since the switching pressure must be applied manually whereupon the electric motor is only switched in when the desired servo assistance takes place against pressure with the starting delay inherent in the system.
Advantages of the Invention As opposed to this, the steering apparatus in accordance with the invention comprising the characterising features of the main claim has the advantage that the energy expenditure is low since the steering apparatus operates intermittently. The starting dynamic is very favourable since the signal pick-off takes place at the steering wheel and the starting characteristic of the electric motor is matched to the requirements of the steering system, that is to say an electric motor with the shortest possible starting up time can be used. Steering shocks and torque jumps at the steering wheel when using the servo assistance are thus avoided. Moreover, a predetermined switching pressure previously applied manually need not be applied.
Advantageous further developments and improvements of the features set forth in the main claim are made possible by the measures set forth in the sub-claims.
Drawing An embodiment of the invention is illustrated in the drawing and is described in detail in the following specification. It shows a hydraulic steering apparatus in diagrammatic representation.
Description of the Embodiment A pump 11 which withdraws pressure medium from a reservoir 1 2, is driven by a permanently energised electric motor 1 0. The pressure medium arrives in a pressure line 13 which leads to a multi-way valve 14. From the multi-way valve 14, two lines 15, 1 6 lead to a double-acting steering cylinder 17 in which a piston 1 8 with piston rods 1 9 is sealingly slidingly guided. The piston rods actuate the steering member for the wheels.
The multi-way valve 14 is actuated from a steering wheel 21 through a linkage 20. An electrical switch 23 is also actuated by the steering wheel or from the steering column and which, for example, is formed as a tilt switch or a torque switch. As a tilt switch it responds as soon as the steering wheel is rotated, as a torque switch it responds when a predetermined torque is reached, which can be adjusted.
From the multi-way valve 14, a line 24 leads to a line 25 which is arranged parallel to the pressure line 13. A pressure limiting valve 26 is arranged in the line 25. The line 25 leads to a return line 27 in which is arranged a filter 28. An hydraulic motor 30 from which two lines 31, 32 lead to the multiway valve 14, is driven by the steering wheel or by a power source. The multi-way valve 14 is a component of the steering valve.The multi-way valve can take up three switching positions l, ll and Ill wherein ll is the neutral position where all pressure medium delivered by the pump 11 flows back to the reservoir whilst positions I and Ill are working positions in which pressure medium either flows to the pressure chamber 33 or to the pressure chamber 34 in the steering cylinder 1 7 or flows back to the reservoir 1 2.
When the vehicle is travelling on a straight line, that is to say it is not being steered, the pump 11 is switched out. As soon as the steering wheel 21 is rotated, the electrical switch 23 is actuated either directly by the steering wheel or through the steering column and as a result the electric motor 10 which drives the pump 11 is immediately switched in. Then the steering can occur in known manner. At the end of a steering operation, that is to say when the steering wheel is again brought to the initial position, the switch 23 switches the electric motor 10 off. Thus, there is a guarantee that the pump 11 only operates when steering is actually occurring.
The starting dynamic of the steering apparatus amounts, for example, to only 60 m/sec with full delivery flow and Pmax 2
CLAIMS 1. A hydraulic steering apparatus which is supplied from a pump driven by an electric motor and which controls pressure medium through a multi-way valve to the steering cylinder which is brought into an operating position by actuating the steering wheel, characterised in that the electric motor and with it the pump is only switched in on actuation of the steering wheel by an electrical switch actuated through the steering wheel or the steering column.
2. Steering apparatus according to claim 1 characterised in that the electrical switch is formed as a torque switch.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    SPECIFICATION A hydraulic steering apparatus State of the Art The invention originates from a hydraulic steering apparatus according to the preamble to the main claim. One known steering apparatus of that kind has the disadvantage that the pump is continually driven, that is to say even when not steering. For this reason, unnecessary energy is used up.
    Furthermore, a steering apparatus is known in which the pump is only switched in when steering and a particular switching pressure is reached in the hydraulic system. Then the electric motor is switched in by a pressure switch. That has the advantage that less energy is required but also has the disadvantage that not only must the said switching pressure be applied but when using the servo assistance a torque jump occurs whereby an accurate steering is impaired. Moreover, the switching in dynamics are bad since the switching pressure must be applied manually whereupon the electric motor is only switched in when the desired servo assistance takes place against pressure with the starting delay inherent in the system.
    Advantages of the Invention As opposed to this, the steering apparatus in accordance with the invention comprising the characterising features of the main claim has the advantage that the energy expenditure is low since the steering apparatus operates intermittently. The starting dynamic is very favourable since the signal pick-off takes place at the steering wheel and the starting characteristic of the electric motor is matched to the requirements of the steering system, that is to say an electric motor with the shortest possible starting up time can be used. Steering shocks and torque jumps at the steering wheel when using the servo assistance are thus avoided. Moreover, a predetermined switching pressure previously applied manually need not be applied.
    Advantageous further developments and improvements of the features set forth in the main claim are made possible by the measures set forth in the sub-claims.
    Drawing An embodiment of the invention is illustrated in the drawing and is described in detail in the following specification. It shows a hydraulic steering apparatus in diagrammatic representation.
    Description of the Embodiment A pump 11 which withdraws pressure medium from a reservoir 1 2, is driven by a permanently energised electric motor 1 0. The pressure medium arrives in a pressure line 13 which leads to a multi-way valve 14. From the multi-way valve 14, two lines 15, 1 6 lead to a double-acting steering cylinder 17 in which a piston 1 8 with piston rods 1 9 is sealingly slidingly guided. The piston rods actuate the steering member for the wheels.
    The multi-way valve 14 is actuated from a steering wheel 21 through a linkage 20. An electrical switch 23 is also actuated by the steering wheel or from the steering column and which, for example, is formed as a tilt switch or a torque switch. As a tilt switch it responds as soon as the steering wheel is rotated, as a torque switch it responds when a predetermined torque is reached, which can be adjusted.
    From the multi-way valve 14, a line 24 leads to a line 25 which is arranged parallel to the pressure line 13. A pressure limiting valve 26 is arranged in the line 25. The line 25 leads to a return line 27 in which is arranged a filter 28. An hydraulic motor
    30 from which two lines 31, 32 lead to the multiway valve 14, is driven by the steering wheel or by a power source. The multi-way valve 14 is a component of the steering valve.The multi-way valve can take up three switching positions l, ll and Ill wherein ll is the neutral position where all pressure medium delivered by the pump 11 flows back to the reservoir whilst positions I and Ill are working positions in which pressure medium either flows to the pressure chamber 33 or to the pressure chamber 34 in the steering cylinder 1 7 or flows back to the reservoir 1 2.
    When the vehicle is travelling on a straight line, that is to say it is not being steered, the pump 11 is switched out. As soon as the steering wheel 21 is rotated, the electrical switch 23 is actuated either directly by the steering wheel or through the steering column and as a result the electric motor
    10 which drives the pump 11 is immediately switched in. Then the steering can occur in known manner. At the end of a steering operation, that is to say when the steering wheel is again brought to the initial position, the switch 23 switches the electric motor 10 off. Thus, there is a guarantee that the pump 11 only operates when steering is actually occurring.
    The starting dynamic of the steering apparatus amounts, for example, to only 60 m/sec with full delivery flow and Pmax 2
    CLAIMS 1. A hydraulic steering apparatus which is supplied from a pump driven by an electric motor and which controls pressure medium through a multi-way valve to the steering cylinder which is brought into an operating position by actuating the steering wheel, characterised in that the electric motor and with it the pump is only switched in on actuation of the steering wheel by an electrical switch actuated through the steering wheel or the steering column.
  2. 2. Steering apparatus according to claim 1 characterised in that the electrical switch is formed as a torque switch.
  3. 3. Steering apparatus according to claim 1 characterised in that the electrical switch is formed as a tilt switch.
  4. 4. Steering apparatus according to one of claims 1 to 3 characterised in that the electric motor is formed as a permanently energised motor.
  5. 5. A hydraulic steering apparatus substantially as herein described with reference to the accompanying drawing.
GB8103945A 1980-02-20 1981-02-09 A hydraulic steering apparatus Withdrawn GB2069429A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19803006297 DE3006297A1 (en) 1980-02-20 1980-02-20 HYDRAULIC STEERING DEVICE

Publications (1)

Publication Number Publication Date
GB2069429A true GB2069429A (en) 1981-08-26

Family

ID=6095064

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8103945A Withdrawn GB2069429A (en) 1980-02-20 1981-02-09 A hydraulic steering apparatus

Country Status (5)

Country Link
JP (1) JPS56135371A (en)
DE (1) DE3006297A1 (en)
FR (1) FR2476010A1 (en)
GB (1) GB2069429A (en)
IT (1) IT1135458B (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0053429A2 (en) * 1980-11-03 1982-06-09 Clark Equipment Company Power steering system
EP0090697A2 (en) * 1982-03-30 1983-10-05 Nissan Motor Co., Ltd. Rack and pinion steering arrangement including an improved neutral position sensor
GB2119326A (en) * 1982-03-25 1983-11-16 Cam Gears Ltd Vehicle steering systems
US4457132A (en) * 1981-11-05 1984-07-03 Trw Inc. Control apparatus
GB2147256A (en) * 1983-09-28 1985-05-09 Trw Cam Gears Ltd Power steering system
GB2154189A (en) * 1984-02-15 1985-09-04 Trw Cam Gears Ltd Power assistance steering system
EP0153805A2 (en) * 1984-02-15 1985-09-04 Trw Cam Gears Limited A power assistance steering system for a vehicle
FR2721574A1 (en) * 1994-06-27 1995-12-29 Daimler Benz Ag Hydraulic power steering comprising a servovalve device between the discharge side and the suction side of a hydraulic pump.

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3843893A1 (en) * 1988-10-04 1990-04-05 Teves Gmbh Alfred Hydraulic servopower steering system for motor vehicles

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0053429A2 (en) * 1980-11-03 1982-06-09 Clark Equipment Company Power steering system
EP0053429A3 (en) * 1980-11-03 1984-02-15 Clark Equipment Company Power steering system
US4457132A (en) * 1981-11-05 1984-07-03 Trw Inc. Control apparatus
GB2119326A (en) * 1982-03-25 1983-11-16 Cam Gears Ltd Vehicle steering systems
EP0090697A2 (en) * 1982-03-30 1983-10-05 Nissan Motor Co., Ltd. Rack and pinion steering arrangement including an improved neutral position sensor
EP0090697A3 (en) * 1982-03-30 1984-08-29 Nissan Motor Co., Ltd. Rack and pinion steering arrangement including an improved neutral position sensor
GB2147256A (en) * 1983-09-28 1985-05-09 Trw Cam Gears Ltd Power steering system
FR2555538A1 (en) * 1983-09-28 1985-05-31 Trw Cam Gears Ltd POWER ASSISTED STEERING SYSTEM FOR VEHICLE USING PRESSURIZED FLUID SELECTIVELY CONTROLLED BY TWO SINGLE-SINGLE VALVES
GB2156752A (en) * 1983-09-28 1985-10-16 Trw Cam Gears Ltd A power assistance steering system for a vehicle
GB2154189A (en) * 1984-02-15 1985-09-04 Trw Cam Gears Ltd Power assistance steering system
EP0153805A2 (en) * 1984-02-15 1985-09-04 Trw Cam Gears Limited A power assistance steering system for a vehicle
EP0153805A3 (en) * 1984-02-15 1986-12-30 Trw Cam Gears Limited A power assistance steering system for a vehicle
FR2721574A1 (en) * 1994-06-27 1995-12-29 Daimler Benz Ag Hydraulic power steering comprising a servovalve device between the discharge side and the suction side of a hydraulic pump.

Also Published As

Publication number Publication date
JPS56135371A (en) 1981-10-22
FR2476010A1 (en) 1981-08-21
IT1135458B (en) 1986-08-20
DE3006297A1 (en) 1981-08-27
IT8119722A0 (en) 1981-02-13

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)