Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D15/00—Steering not otherwise provided for
  • B62D15/02—Steering position indicators ; Steering position determination; Steering aids

Definitions

• the invention relates to a device for detecting a rotary movement according to the preamble of claim 1 and a steering system equipped therewith according to
• DE 100 37 211 A1 describes a device for detecting a rotary movement of a steering handle of a vehicle steering system.
• An axially displaceable element arranged on a steering shaft forms a movement screw on the steering shaft with a gear connection formed as a thread.
• the axially displaceable element is axially guided in a longitudinal guide, consisting of a push rod on the element and a guide channel for the push rod.
• a magnetic irregularity on the axially displaceable element is detected by a galvano-magnetic sensor and the longitudinal movement of the axially displaceable element is detected. This enables absolute detection of the rotary movement of the steering handle, but the device described is not exact because of the inevitable play of the longitudinal guide.
• EP 1 114 765 A2 describes a device for detecting a rotational movement in a vehicle steering system, the rotational movement of the shaft to be detected being translated into a rotational movement of a screw shaft via a backlash-free gear.
• the rotational movement of the screw shaft is detected in a manner similar to that of the shaft described in DE 100 37211 A1, it being possible for the axially displaceable element to be spring-loaded in the radial direction of the shaft.
• the device described in EP 1 114 765 A2 is complex to manufacture and requires a relatively large amount of space.
• the longitudinal guide of the axially displaceable element is not completely free of play. The measuring accuracy of the device is affected.
• the invention has for its object to provide a device for detecting a rotational movement in a vehicle steering system, which allows a very high measurement accuracy with a simple structure and minimal space requirements.
• a steering system equipped with it is to be proposed.
• the object is achieved with a device with the features of claim 1 and with a steering system with the features of the independent claim.
• a shaft is rotatably mounted in a frame, on which an element which is axially displaceable in the direction of the shaft is arranged and which is connected to the shaft via a gear connection which transforms the rotary movement of the shaft into a longitudinal movement.
• the axially displaceable element is guided in the axial direction with a longitudinal guide prestressed in the radial direction of the shaft, a detection device being provided which detects the longitudinal movement of the axially displaceable element.
• a frame-side component of the longitudinal guide is seated on the axially displaceable element on first inclined surfaces which extend obliquely to one another and in the axial direction of the axially displaceable element.
• the axially displaceable element and the shaft engage in one another without play via second inclined surfaces of the geared connection, the first inclined surfaces and the second inclined surfaces having the same inclination directions with respect to one another.
• the invention is therefore based on the knowledge that both the first and second inclined surfaces are formed uniformly, wherein they have the same, preferably trapezoidal, inclination directions.
• the first inclined surfaces provided for the axial guidance are shaped in the same way as the second inclined surfaces along the circumferential direction of the geared connection. This has the advantage that a radially oriented pressure exerted on the first inclined surfaces via the frame-side component in the geared connection causes the second inclined surfaces there to be axially pressed on and thus ensures sufficient backlash that ensures effective positive locking.
• the gear connection between the shaft and the axially displaceable element is preferably screw-like or thread-like and has corresponding (second) inclined surfaces on the shaft and / or (first) inclined surfaces on the axially displaceable element, which abut one another.
• the Inclined surfaces of the gear connection and the inclined surfaces between the frame-side component and the axially displaceable element each have the same directions of their inclinations.
• the frame-side component is preferably a pressure piece that is prestressed, for example, by spring force or hydraulic pressure.
• the displaceable element is preferably designed as a nut which is axially guided on the shaft designed as a thread.
• first inclined surfaces on the axially displaceable element in an axially guided recess directed radially from the lateral surface of the element to its longitudinal axis.
• the depression preferably has a trapezoidal cross section.
• the axially displaceable element is preferably annular or cylindrical or sleeve-shaped or angular around the shaft, the gear connection between the shaft and the axially displaceable element being designed as a thread, forming a movement screw.
• the thread is preferably formed as a trapezoidal thread or as a ball recirculation.
• the frame-side component of the longitudinal guide is accommodated in the recess of the axially displaceable element.
• the rotational movement of the shaft is via the gear connection between the Shaft and the axially displaceable element in a longitudinal movement of the same.
• the longitudinal displacement of the axially displaceable element is recorded via the detection device with an evaluation circuit.
• a sensor or a signal transmitter is arranged on the circumference of the axially displaceable element, each communicating with a signal transmitter or sensor which is arranged adjacent to this on the frame or frame-side component of the longitudinal guide.
• the sensor can be a magnetoresistive sensor which is essentially formed from one or more meandering conductor tracks made of a ferromagnetic nickel-cobalt alloy which is vapor-deposited on a silicon substrate and is passivated by a silicon-nitride protective layer.
• the resistance of the ferromagnetic nickel-cobalt alloy shows a strong dependence on a magnetic field in relation to the magnetic field direction.
• the signal transmitter can be a bar magnet, which is preferably a greater axial extension than the structurally predetermined measuring range of the longitudinal movement of the axially displaceable element, in order to enable an installation tolerance of the signal transmitter or of the axially displaceable element relative to the sensor. It can also be expedient to design the signal transmitter as a ring magnet.
• the axially displaceable element as a nut which is arranged to be axially movable on a shaft designed as a steering spindle.
• This arrangement is " particularly suitable for detecting the steering angle in the area of the steering handle (steering wheel).
• the displaceable element as a threaded nut
• the shaft being designed as a threaded piece on which the threaded nut is arranged to be axially movable.
• the threaded piece is in turn attached to a steering nut, which is attached to a ball screw
• Fig. 1 shows a schematic cross section of a device for detecting a rotational movement on a steering spindle
• Fig. 2 shows a schematic longitudinal section along the line I-1 through the measuring device shown in Fig. 1
• Fig. 3 shows a schematic cross section of a differently designed device for detecting a rotational movement on a rack.
• FIG. 1 shows a schematic cross section through a device 1 for detecting a rotary movement of a shaft 3 in a vehicle steering system.
• the shaft 3, designed as a steering shaft, is rotatably mounted in the frame 2.
• the device 1 is intended to record the rotational movement and the rotational position of the shaft 3 absolutely.
• a detection device 7 is provided, which consists of a signal transmitter 14, which is designed as a bar magnet 17, and a sensor 15, which is designed as a magnetoresistive sensor or sensor surface 16.
• FIG. 2 shows in a longitudinal section along the line II in FIG. 1 through the device 1 for detecting a rotary movement
• the bar magnet 17 extends over an axial region 18 of an axially displaceable element 4 which is arranged on the shaft 3 and is on this element 4 set.
• the sensor 15 is arranged opposite the bar magnet 17 with a small radial distance.
• the sensor 15 is fixed on the frame 2. It may also be expedient to arrange the sensor on the axially displaceable element 4 and to arrange the bar magnet 17 fixed to the frame.
• the gear connection 5 is shown in the Embodiment as a thread 12, in particular as a trapezoidal thread 13 with
• the cylindrical, sleeve-shaped, axially displaceable element 4 forms a movement screw with the trapezoidal thread 13 and the shaft 3.
• the magnetoresistive sensor 16 is flooded by the field lines of the bar magnet 17 and a signal - planar Hall voltage or change in resistance - is generated in the sensor 16.
• the signal can be evaluated by a control and / or regulating unit of the vehicle steering system and used to control a servo motor of the vehicle steering system.
• the axially displaceable element 4 can also be arranged on a steering nut instead of on a steering shaft, the detection device detecting the longitudinal movement of a rack.
• the frame-side component 8 of the longitudinal guide 6 is brought to bear against the axially displaceable element 4 on first inclined surfaces 9, 9 'which run obliquely to one another and in the direction of the longitudinal axis 19.
• the frame-side component 8 of the longitudinal guide 6 has (first) inclined surfaces 9 and the axially displaceable element 4 (first) inclined surfaces 9 '.
• The, inclined surfaces 9 'on the axially displaceable element 4 are designed as trapezoidal approximating surfaces.
• the frame-side, spring-loaded component 8 of the longitudinal guide 6 protrudes into the depression 11 thus formed in the axially displaceable element 4 and lies with its inclined surfaces 9 against the inclined surfaces 9 'of the recess 11 without play.
• the space requirement of the device 1 is minimized in that the frame-side component 8 of the longitudinal guide 6 is kept flat and protrudes with its predominant part of its radial extent into the recess 11 of the axially displaceable element 4.
• the gear connection 5 can be a thread or a helical link guide or a ball recirculation.
• the rod magnet 17 or signal transmitter 14 is larger in its axial extension 18 than is required by the design measuring range of the longitudinal movement of the axially displaceable element 4.
• FIG. 3 shows a measuring device 1 'as the second exemplary embodiment of the invention.
• the arrangement of the measuring device on a rack 129 in an electric steering system is shown there.
• This is provided with a ball screw thread 135 which interacts with a steering nut 128.
• the steering nut 128 is mounted in the housing 100 by a bearing with rolling elements 111 and is driven by an electric motor 126 via a gear designed as a belt drive 127, whereby the rack 129 or push rod can be deflected to assist manual deflection via a steering pinion (not shown).
• the steering nut 128 is provided with a threaded piece 133 on which a threaded nut 136 is arranged so as to be axially movable.
• the threaded piece 133 and the threaded nut 136 represent the components designed according to the invention, namely the rotatably mounted shaft or the axially displaceable element, which have inclined surfaces of identical design (not shown here, but see FIG. 2).
• the sensor components 130 and 131 for detecting the axial movement 137 of the threaded nut 136 are arranged thereon.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
• Power Steering Mechanism (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=33521184

Family Applications (1)

Country Status (5)

Families Citing this family (13)

Family Cites Families (8)

• 2003
  • 2003-06-30 DE DE10329293A patent/DE10329293A1/de not_active Withdrawn
• 2004
  • 2004-06-18 US US10/562,510 patent/US20060170415A1/en not_active Abandoned
  • 2004-06-18 CN CN200480018480.9A patent/CN1812908A/zh active Pending
  • 2004-06-18 EP EP04740019A patent/EP1638833A1/de not_active Withdrawn
  • 2004-06-18 WO PCT/EP2004/006565 patent/WO2005000663A1/de not_active Application Discontinuation

Non-Patent Citations (2)

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