Testing rotary movement-electrical signal transducer system, particularly for vehicle wheel anti-block transducer systems

• US 4,092,853 A
• Filed: 10/18/1976
• Issued: 06/06/1978
• Est. Priority Date: 10/25/1975
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Fleischer, Helmut, Schneider, Erich, Schnaibel, Eberhard
• Primary Examiner(s): Ruehl, Charles A.
• Application Number:
  US05/733,125
• Time in Patent Office: 596 Days
• Field of Search: 73/2, 73/5, 73/121, 303/92, 340/52 B, 324/186
• US Class Current: 73/121
• CPC Class Codes: B60T 2270/406 Test-mode; Self-diagnosis
• CPC Class Codes: B60T 2270/416 Wheel speed sensor failure
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: G01P 21/02 of speedometers
• CPC Class Codes: G01P 3/60 by measuring or comparing frequency of generated currents or voltages frequency comparators H03K5/26

Abstract

The time duration of output pulses from the transducer, including wave-shaping circuits, if used, is measured and compared with respect to predetermined time limits. Two sequential pulses are measured and stored. If both pulses are shorter than a predetermined time interval, no alarm signal is generated; if the first pulse is longer than a predetermined time interval and the second also longer than a predetermined time interval, an alarm signal generation circuit, otherwise activated by the second, longer signal, is inhibited (since acceleration or deceleration of the wheel is indicated); if, however, the time duration of the second sequential pulse is longer than a predetermined time interval, but the time duration of the preceding pulse is shorter than its time duration threshold value, the malfunction signal is not inhibited, indicative of malfunction, loose contacts, or the like.

Claims

1. Method of testing a rotary movement -- electrical signal transducer system providing pulses in synchronism with rotation of a rotary device having widely varying speeds, such as the wheel of an automotive vehicle, comprising the steps of

measuring the time duration of two successive pulses;

comparing the time duration of a first occurring pulse with a first predetermined time interval and having a first limited time duration with respect to a fixed longest time interval;

generating a first evaluation signal if the measured time duration of the first pulse exceeds said first limited time duration;

comparing the time duration of the second occurring pulse with a second predetermined time interval which is longer than said first predetermined time interval and having a second limited time duration with respect to said fixed longest time interval;

generating a second evaluation signal and forming a preliminary error, or malfunction signal if the measured time duration of the second occurring pulse exceeds said second limited time duration;

logically combining said first and second evaluation signals and

(a) inhibiting generation of the preliminary error signal if

the first pulse is shorter than the first interval, and the second pulse is shorter than the second interval;

(b) inhibiting transmission of the preliminary error signal if

the first pulse is longer than said first interval;

the first pulse is longer than the first interval and the second pulse is also longer than said second interval, indicative of deceleration of the wheel; and

(c) transmitting said preliminary error signal if the first pulse is shorter than said first predetermined interval and the second pulse is longer than said second predetermined time interval.

2. Method to test a vehicle wheel anti-block system

wherein the rotary device is a vehicle wheel and rotary movement is rotation of the wheel, said method comprising the steps of claim 1.

3. Method according to claim 2, wherein the second predetermined time interval is longer than the signal period of the maximum permissible temporal change of the last pulse before stopping of the wheel;

5. Method according to claim 3, including the steps of

continuously storing the time duration of pulses for the duration of the respective pulses until occurrence of the next subsequent pulse.

7. Vehicle wheel anti-block system, including the testing system claimed in claim 5,

4. and the first time interval is shorter than the signal period of the last pulse before stopping of the wheel.

6. System to test a rotary movement -- electrical signal transducer system providing pulses in synchronism with rotation of a rotary device having widely varying speeds, such as a wheel of an automotive vehicle comprising

a counter (20), a clock generator (22) connected to step the counter in accordance with generation of the clock pulses;

first decoding means (31) and second decoding means (30), each decoding count outputs from the counter at discrete count stage positions;

a memory (40) connected to one of the decoding means (31);

and a blocking gate (50) having the output from the second of the decoding means (30) and from said memory (40) applied thereto and having an output providing an evaluation signal representative of the pulse lengths of successive pulses, one derived from the second of the decoding means (30) and the other from said memory (40), the transducer (10) of said transducer system providing input pulses to said counter to cause the counter to count, at the rate determined by the clock (22) upon first occurrence of any one pulse, the first decoding means (31) being connected to the counter to decode counting to lower numbered count stages (e, f), said second decoding means (30) providing an output to the blocking gate (50) from a count stage which is higher, and thus representative of a time interval which is longer than time interval decoded by said first decoding means (31) whereby the memory (40) will store a signal representative of the time duration of the first of two successively occurring pulses, the blocking gate (50) inhibiting generation of an output signal derived from said second decoding means (30) if said first decoding means (31) has decoded the preceding signal to have a longer time duration than said first time interval required for the counter (20) to reach the count stage at which said first decoding means (31) responds, but transmitting an output signal from the second decoding means (30) indicative of the second pulse being in excess of the time interval for the counter to reach the count stage at which the second decoding means (30) responds if said first decoding means (31) has decoded the preceding signal to have a shorter time duration than the time interval required for the counter (20) to reach the count stage at which said first decoding means (31) responds.

8. wherein said device comprises a vehicle wheel and the rotary movement is rotation of the wheel.

9. System to test a rotary movement -- electrical signal transducer (10,11,12) for an automotive vehicle wheel (W) in a brake anti-block system (70) providing a train of successive pulses upon rotation of the wheel comprising

a counter (20), a clock generator (22) connected to the counter and causing stepping of the counter to thereby provide predetermined time intervals;

two decoding means (30,

     31) connected to the output of the counter (20) to derive a malfunction signal and an inhibit signal, respectively, the malfunction signal decoding means (30) being connected to a higher count stage of the counter than the inhibit signal decoding means (31), whereby the malfunction signal decoding means will determine a longer time interval than the inhibit signal decoding means;

a blocking gate (50) and an evaluation output signal processing means (60,

     70) connected to the blocking gate (50);

a memory (40) connected to the output of the inhibit decoding means (31) and storing the output signal from the inhibit decoding means (31) until a next subsequent pulse from the transducer (10, 11,

     12), the output of the memory (40) being connected to the blocking gate (50), the blocking gate further having the output from the malfunction decoding means (30) applied thereto to provide an indication to the evaluation means (60,

     70) if;

(a) a pulse from the transducer (10, 11,

     12) subsequent to a preceding prior pulse therefrom has a longer time duration than the time interval necessary for the counter to count to the count stage at which the malfunction logic means (30) will respond, and

(b) the preceding pulse, as stored in the memory (40), has a time duration which is shorter than the time duration taken by the counter (20) to count to the count stage at which the inhibit logic means (31) will respond to inhibit an output from the blocking gate unless two subsequently occurring pulses each have respective pulse time durations which are both longer than the respective time intervals determined by the respective inhibit signal decoding means (31) and by the malfunction signal decoding means (30).