Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
  • G01P13/00—Indicating or recording presence, absence, or direction, of movement
  • G01P13/02—Indicating direction only, e.g. by weather vane
  • G01P13/04—Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
  • G01P13/045—Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement with speed indication
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
  • G01P13/00—Indicating or recording presence, absence, or direction, of movement
  • G01P13/02—Indicating direction only, e.g. by weather vane
  • G01P13/04—Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/142—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices
  • G01D5/147—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
  • G01D5/245—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
  • G01D5/2451—Incremental encoders

Definitions

• the present invention relates to a method for detecting the direction of rotation of a wheel by means of Hall probes, which are arranged in the circumferential direction of the wheel, by means of evaluation signals which are phase-shifted from one another.
• phase information is required, which can be provided by two Hall sensors offset by 90 ° to one another, as will be explained below with reference to FIGS. 5 and 6.
• DE 41 04 902 AI discloses a method and an arrangement for detecting a direction of movement, in particular one.
• Direction of rotation known.
• two signals which are phase-shifted by 90 ° and which are derived from two receivers offset in the direction of movement of a signal source are formed by adding and subtracting the output signals.
• the direction of rotation can be clearly determined from the sign of the 90 ° phase shift between the sum and difference signals.
• this method is very sensitive to DC magnetic fields. So there is an offset of the sum signal compared to
• the method should be insensitive to constant magnetic fields.
• a first, a second and a third Hall probe are arranged so that the second Hall probe is positioned between the first and the third Hall probe.
• Two evaluation signals shifted by 90 ° are obtained from the output signals of the first to third Hall probes, with one change the direction of rotation preferably results in a change of sign of the second evaluation signal in relation to the first evaluation signal.
• the second Hall probe is advantageously located exactly in the middle between the first and the third Hall probe, since the vibration amplitudes of the evaluation signals are then maximum.
• This method therefore only requires three Hall probes, which can be accommodated in a Hall sensor.
• the direction of rotation for example of a gearwheel, can be reliably determined from a change in the sign of the second evaluation signal.
• Figure 1 is a schematic representation of a sensor already known according to the prior art.
• Fig. 2 output signals of the Hall probes of this known sensor
• FIG. 3 and 4 are circuit diagrams of the evaluation electronics for obtaining the evaluation signals according to the method described here;
• Fig. 5 shows an arrangement with two Hall sensors according to the prior art, and
• Fig. 6 output signals of the Hall probes of these known Hall sensors.
• FIG. 1 shows a known Hall sensor 13 which has Hall probes 14, 15 and 16 which are arranged in the direction of rotation of the gear wheel 8, the Hall probe 15 in the middle is provided between the Hall probes 14 and 16.
• the Hall probes 14 to 16 deliver output signals S1 to S3 (see FIG. 2), which are approximately sinusoidal and are therefore also treated in the following. Hall sensor 14 thus delivers this
• Output signal Sl which has a maximum value when the tooth 7 passes through the Hall sensor 14, while a gap between the teeth 7 results in a minimum value for the output signal Sl.
• the output signals S1 to S3 can be easily digitized with the aid of a comparator, so that the signals S1 to S3 assume a course corresponding to the output signals 9 and 10 in FIG. 6. In the following, however, it should be assumed that the signals are processed further in an analog manner.
• Evaluation signal A obtained from the subtraction of the output signal S3 from the output signal S1.
• a second evaluation signal B is obtained from the addition of the output signal S3 to the output signal S1 and the subtraction of the double output signal S2 from this sum.
• the method is not limited to the sampling at the zero crossing of the signal A.
• the sampling can also take place at other values of the signal A.
• the direction detection can take place by evaluating the tendency of the second evaluation signal B for the sample value.
• sampling at the zero crossing of signal A in conjunction with direction detection using the sign of signal B represents a particularly preferred method.
• one of the evaluation signals (A, B) can be used to generate switching edges and the respective other evaluation signal (A, B) can be sampled with these switching edges, the direction of rotation being determined from the relationship between the samples of the edges.
• the method therefore enables reliable detection of the reversal of the direction of rotation of a gearwheel with only three Hall probes on one Hall sensor.
• evaluation signals A and B For the generation of evaluation signals A and B, operational amplifier circuits can be used per se without further notice. However, transistor circuits are also possible, as shown in FIGS. 3 and 4. 3 and 4, Slp and Sin mean the output signals of the Hall probe 14,
• ERS ⁇ T2BLAT ⁇ (RULE 26) S2p and S2n the output signals of the Hall probe 15 and S3p and S3n the output signals of the Hall probe 16.
• the output signal A is obtained in the circuit of FIG. 3 with the output connections 17 and 18, while the evaluation signal B is obtained with the circuit of FIG. 4 with the output connections 19 and 20.
• the Hall probes 14, 15, 16 are connected to the respective differential amplifiers of these circuits in such a way that only differential fields are used for the control, while a large superimposed magnetic bias only causes a common mode shift that is effective and is suppressed without any significant side effects.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Transmission And Conversion Of Sensor Element Output (AREA)
• Indicating Or Recording The Presence, Absence, Or Direction Of Movement (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (2)

Family

ID=7827645

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (18)

Citations (3)

Family Cites Families (6)

• 1997
  • 1997-04-24 DE DE19717364A patent/DE19717364C1/de not_active Expired - Fee Related
• 1998
  • 1998-04-23 JP JP54474098A patent/JP2001521630A/ja active Pending
  • 1998-04-23 CN CN98804477A patent/CN1260879A/zh active Pending
  • 1998-04-23 WO PCT/DE1998/001140 patent/WO1998048284A2/de not_active Application Discontinuation
  • 1998-04-23 EP EP98931990A patent/EP0977997A2/de not_active Withdrawn
  • 1998-04-23 KR KR1019997009771A patent/KR20010020194A/ko not_active Application Discontinuation
  • 1998-04-23 CA CA002287182A patent/CA2287182A1/en not_active Abandoned

Patent Citations (3)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events