JPH0633420Y2 - Rotation direction detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a rotation direction detecting device using an electromagnetic pickup sensor.

(Prior Art) A rotation detection device using an electromagnetic pickup sensor has a rotating body composed of gears, and the electromagnetic pickup sensor arranged near the peripheral surface of the rotating body is configured by winding a coil around a permanent magnet. ing. Since this device is relatively inexpensive and has the strength to withstand severe conditions such as vibration, it is widely used to detect the number of rotations and the rotation angle in vehicles, but it can detect the direction of rotation. There was nothing.

(Problems to be solved by the invention) Therefore, the development of a device capable of detecting the rotation direction using an electromagnetic pickup sensor has been awaited. A rotation detecting device using an optical sensor is disclosed in JP-A-60-171466.

(Means for Solving Problems) The present invention has been made in order to meet the above-mentioned demand, and its gist is (a) at least one pair of N-pole magnetized regions, S
A rotor having polar magnetized regions and angular intervals Θ ₁ , Θ ₂ from one magnetized region to the other magnetized region being different in the clockwise direction and the counterclockwise direction; The corrugated portion, which is arranged near the peripheral surface of the rotating body, outputs a corrugated portion having one polarity as viewed from the reference level corresponding to the N-pole magnetized region as the rotating body rotates, and continuously outputs the corrugated portion having the other polarity. From the electromagnetic pickup sensor for outputting the waveform portion having the other polarity corresponding to the S pole magnetized area and subsequently outputting the waveform portion having the other polarity. A waveform shaping section that shapes a waveform section of either polarity in the detected wave into a rectangular pulse, and (d) a time interval of at least two pairs of three consecutive pulses received from the waveform shaping section. Measuring unit for measuring the distance Ta, Tb, (e)
Based on the information of the pulse time intervals Ta and Tb from the measuring unit, it is determined which of the two different angular intervals Θ ₁ and Θ ₂ the time interval Ta of the adjacent pulse corresponds to. Based on the discrimination information from the first discriminating unit and (e) the discriminating information from the first discriminating unit and the pulse time intervals Ta and Tb from the measuring unit, the previously specified angle between the two different angular intervals Θ ₁ and Θ _2. pulse time interval T ₁ corresponding to the interval Θ ₁
(G) a second calculation part for calculating a time ₁ ′ required for the specified angular interval Θ ₁ to pass through the electromagnetic pickup sensor, and (h) a first calculation part. The rotation of the rotor is compared by comparing the pulse time interval T ₁ corresponding to the specific angular interval Θ ₁ calculated in step _{1 with} the transit time T ₁ ′ of the specific angular interval Θ ₁ calculated by the second calculating section. The rotation direction detecting device is provided with a second determining unit that determines a direction.

(Operation) At least a pair of N-pole magnetized region and S-pole magnetized region is arranged on the peripheral surface of the rotating body, and the angular intervals Θ ₁ , Θ ₂ from one magnetized region to the other magnetized region are Since the rotation direction and the counterclockwise direction are different, pulses formed by shaping the detection wave from the electromagnetic pickup sensor are not output at equal time intervals.

In the measuring section, at least 2 out of 3 consecutive pulses
The time intervals Ta and Tb of the pair of pulses are measured. Then, the first discriminating unit discriminates which of the angular intervals Θ ₁ and Θ ₂ the time interval Ta of the adjacent pulses corresponds to.

In the first calculation unit, based on the determination information of the first determination section, the two different angular intervals theta _1, theta pulse time interval T ₁ corresponding to the angular spacing eg theta ₁ identified in advance of ₂
Is calculated.

On the other hand, in the second calculation unit, the specified angular interval Θ ₁
Time it takes for the object to pass the electromagnetic pickup sensor
Calculate T ₁ ′.

The pulse time interval T ₁ is dependent direction of rotation of the rotating body, the passage 'less than, the transit time T ₁ when the other rotational direction' time T ₁ is greater than when the one rotational direction. Therefore, the second discriminating unit can discriminate the rotation direction by comparing T ₁ and T ₁ ′.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings from FIG. 1 to FIG. In FIG. 1, 10 is a rotating body, and this rotating body 10 is fixed to a shaft 11 whose rotation is to be detected. A plurality of recesses 10a are formed on the peripheral surface of the rotating body 10, and U-shaped permanent magnets 12 are formed in the recesses 10a at both ends 12a, 1a.
It is housed in a state in which 2b is projected from the peripheral surface of the rotating body 10. The N and S poles of both ends 12a and 12b of the permanent magnet 12 respectively constitute a pair of different magnetized regions in the rotating body 10.

The permanent magnets 12 are arranged at equal intervals at angular intervals Θ ₀ . Further, the angular spacing Θ ₁ between the N and S poles of each permanent magnet 12 and the angular spacing Θ ₂ between the N and S poles of the adjacent permanent magnets 12 are different from each other. The angle interval Θ ₁ is the angle interval from _one magnetic pole, for example, the N pole, to the S pole in the clockwise direction, and the angle interval Θ ₂ is the angle from the N pole to the S pole in the counterclockwise direction. It is an interval. In this embodiment, Θ ₁ is set sufficiently smaller than Θ ₂ .

An electromagnetic pickup sensor 20 is arranged near the peripheral surface of the rotating body 10. The electromagnetic pickup sensor 20 is configured by winding a coil 22 around an iron core 21.

The detected wave from the electromagnetic pickup sensor 20 is processed by the circuit shown in FIG. 2 to detect the rotating direction of the rotating body 10, that is, the shaft 11.

More specifically, every time the permanent magnet 12 passes through the electromagnetic pickup sensor 20 as the rotor 10 rotates, an electromotive voltage, that is, a detection wave is generated in the coil 22 of the electromagnetic pickup sensor 20. The detected wave is output in different modes depending on the rotating direction of the rotating body 10. Clockwise direction (hereinafter referred to as A direction)
In the case of the rotation, the S pole of each permanent magnet 12 first passes through the electromagnetic pickup sensor 20, and then the N pole passes. Therefore, for example, as shown in FIG. 3, the detected wave first has a waveform that changes from negative to positive corresponding to the S pole, and then has a waveform that changes from positive to negative corresponding to the N pole. On the other hand, when the rotating body 10 rotates in the counterclockwise direction (hereinafter referred to as the B direction), the N pole of each permanent magnet 12 passes through the electromagnetic pickup sensor first, and then the S pole passes through. Therefore, for example, as shown in FIG. 4, the detected wave first has a waveform that changes from positive to negative corresponding to the N pole, and then has a waveform that changes from negative to positive corresponding to the S pole.

The detection wave generated by the electromagnetic pickup sensor 20 is shaped into a rectangular pulse by the waveform shaping section 30 as shown in FIGS. 3 and 4. Since this pulse is obtained by shaping the positive side portion of the detected wave, one pulse is generated each time each magnetic pole passes through the electromagnetic pickup sensor 20, and in the case of the S pole, it is delayed in the case of the N pole. It occurs early. It should be noted that this time difference is important for the later-described rotation direction determination. Further, since the angular intervals Θ ₁ and Θ ₂ are different, the time interval between adjacent pulses is not constant even if the rotation speed of the rotating body 10 is constant, and two values are alternately taken. This difference in pulse time interval is also important.

The pulse is sent to the measuring unit 31, where the time interval Ta between adjacent pulses and the time interval Tb between every other pulse are measured every time a pulse is input. Specifically, while measuring the time interval Ta from the rising time point of the specific pulse to the rising time point of the next pulse, the time interval from the rising time point of the pulse of the specific pulse to the rising time point of the next pulse Measure Tb.

The above-mentioned every other pulse time interval Tb always represents a time interval corresponding to the angular interval Θ ₀ between the adjacent permanent magnets 12. However, the pulse time interval Ta differs depending on how the specific pulse is selected, which of the angular intervals Θ ₁ and Θ _{2 in} FIG. ₁ is represented.

Therefore, the first discriminating unit 32 receives the information of the pulse time intervals Ta and Tb from the measuring unit 31 and discriminates which of the angular intervals Θ ₁ and Θ ₂ the pulse time interval Ta corresponds to. That is, the first discriminating unit 32 compares Ta and Tb / 2, and when Ta <Tb / 2, discriminates that Ta corresponds to the angular interval Θ ₁ and Ta> Tb. In the case of / 2, it is determined to correspond to the angular interval Θ ₂ .

The discrimination information of the first discriminator 32 is sent to the first calculator 33. When the first calculation unit 33 receives the determination information that the pulse time interval Ta corresponds to the angular interval Θ _1, it calculates T ₁ = Ta. Here, T ₁ represents the pulse time interval corresponding to the angular interval Θ ₁ . Further, the pulse time interval Ta is equal to the angular interval Θ ₂
When it receives the discrimination information that it corresponds to T _1,
= Tb-Ta is calculated.

On the other hand, the second calculating unit 34 receives the pulse time interval Tb from the measuring unit 31 and calculates the angular velocity ω.

ω = Θ ₀ / Tb The second calculation unit 34 further performs the following calculation based on the angular velocity ω.

T ₁ ′ = Θ ₁ / ω Note that the above Θ ₀ and Θ ₁ are input as constants to the second calculation unit 34 in advance.

T ₁ ′ obtained by the above equation represents the time required for the angular interval Θ ₁ between the N and S poles of each permanent magnet 12 to pass through the electromagnetic pickup sensor 20, in other words, FIG. At the zero crossing point of the detected wave corresponding to the S pole passage and N
The time interval between the zero cross point of the detected wave corresponding to the pole passage is shown. Moreover, the passage time T ₁ ′ of is constant even if the rotating direction of the rotating body 10 is different, if the rotating speeds are equal.

The pulse time interval T ₁ corresponding to the angular interval Θ ₁ takes different values depending on the rotation direction even if the rotation speed is the same. That is, in the case of rotation in the A direction, the pulse corresponding to the first S pole is delayed and the pulse corresponding to the next N pole is generated earlier, so that the pulse time interval T ₁ is shorter than the passage time T ₁ ′. . On the other hand, in the case of rotation in the B direction, the pulse corresponding to the first N pole occurs earlier and the pulse corresponding to the next S pole occurs later, so that the pulse time interval T ₁ is equal to the passage time T ₁ ’Longer than.

Therefore, the second discriminating unit 35 discriminates the rotation direction by comparing the pulse time interval T ₁ from the first arithmetic unit 33 and the time T ₁ ′ from the second arithmetic unit 34, and displays the discriminating signal on the display unit. Or output to various control devices.

The configuration of the measuring unit 31, the first discriminating unit 32, the first arithmetic unit 33, the second arithmetic unit 34, and the second discriminating unit 35 in the above embodiment is replaced by a microcomputer 40 as shown by the imaginary line in FIG. be able to. In this case, the microcomputer 40 executes the interrupt routine shown in FIG. More specifically, first, the pulse time intervals Ta and Tb are measured using a free running counter (step 100). Next, Ta and Tb / 2
(Step 101), and if Ta <Tb / 2, T ₁
= Computes a Ta (step 102), in the case of Ta> Tb / 2 performing the calculation of T ₁ = Tb-Ta (step 103).

Next, the angular velocity ω is calculated (step 104), and the passage time T ₁ ′ is calculated based on this angular velocity ω (step 10).
Five).

In the next step 106, T ₁ and T ₁ ′ are compared and T ₁ <T ₁ ′
In the case of, the rotation direction is judged to be the A direction and a discrimination signal is output to the display device or the like (step 107). In the case of T ₁ > T ₁ ′, it is judged that the rotation direction is the B direction. A discrimination signal is output (step 108).

The first calculation unit 33 calculates the pulse time interval T ₂ corresponding to the angular interval Θ ₂ between the N and S poles of the adjacent permanent magnets 12,
The second computing unit 34 computes the time T ₂ ′ required for the angular interval Θ ₂ to pass through the electrode pickup sensor 20, and the second discriminating unit 35 compares these T ₂ and T ₂ ′ to rotate them. The direction may be determined.

Further, in the measuring unit 31, among the three consecutive pulses, the first and second pulse time intervals and the second and third pulse time intervals
The pulse time interval with the second pulse may be measured. in this case,
The first discriminating unit 32 compares both pulse time intervals. Also,
Since the sum of both pulse time intervals is constant as long as the rotation speed is constant, the angular speed ω is calculated based on this sum and the passage time corresponding to one angular interval is calculated.

The present invention is not limited to the above-mentioned embodiment and various modes are possible. For example, the rotating body may be provided with only one permanent magnet. Further, instead of the U-shaped permanent magnet, each magnetized region may be configured by attaching one or multiple permanent magnet pieces such as magnet rings magnetized in the radial direction of the rotating body to the rotating body.

In the above device, a function of calculating the rotation speed from the angular velocity ω and outputting the calculation result may be added. Further, every other pulse may be used as a signal for calculating the rotation angle or a timing signal for control.

Further, in the second calculation unit, information such as the angular velocity ω and the rotation speed necessary for the calculation of T ₁ ′ may be obtained from another rotation detection means.

(Effect of the Invention) As described above, in the rotation direction detecting device of the present invention,
The rotation direction can be detected without impairing the advantages of the inexpensive and permanent electromagnetic pickup sensor.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a front view of a rotation detecting device, FIG. 2 is a circuit block diagram of the device, and FIGS. FIG. 5 is a time chart of a detection wave and a shaping pulse when the rotating body rotates in different directions, and FIG. 5 is a flowchart of an interrupt routine executed by a microcomputer in another embodiment. 10 ... Rotating body, 12a, 12b ... Magnetic region (both ends of permanent magnet), 20 ... Electromagnetic pickup sensor, 21 ... Iron core, 22
…… Coil, 30 …… Waveform shaping section, 31 …… Measuring section, 32 ……
1st discrimination | determination part, 33 ... 1st calculation part, 34 ... 2nd calculation part, 35
...... Second discriminating unit, 40 ... Microcomputer.

Claims (1)

[Scope of utility model registration request] (A) At least a pair of N-pole magnetized regions and S-pole magnetized regions are arranged on the peripheral surface, and the angular intervals Θ ₁ , Θ ₂ from one magnetized region to the other magnetized region are (B) It is arranged near the peripheral surface of the rotating body and the rotating body that is different in the clockwise direction and the counterclockwise direction. As the rotating body rotates, it is viewed from the reference level corresponding to the N-pole magnetized region. The waveform portion having one polarity is output and the waveform portion having the other polarity is subsequently output, and the waveform portion having the other polarity is output corresponding to the S-pole magnetized region and the one polarity is continuously output. An electromagnetic pickup sensor that outputs a waveform section having a waveform, (c) a waveform shaping section that shapes a waveform section of either polarity in a detected wave from the electromagnetic pickup sensor into a rectangular pulse, and (d) a waveform shaping section Receiving the pulse At least two sets of pulse interval Ta of the three pulses continue, Tb
(E) Based on the information of the pulse time intervals Ta and Tb from the measurement unit, the time interval Ta of the adjacent pulse is one of the two different angular intervals Θ ₁ and Θ ₂ . And (f) based on the discrimination information from the first discrimination unit and the pulse time intervals Ta and Tb from the measurement unit, the two different angular intervals Θ _{A first} calculation unit that calculates a pulse time interval T ₁ corresponding to a previously specified angular interval Θ ₁ of ₁ and Θ ₂ , and (g) the specified angular interval Θ ₁ passes through the electromagnetic pickup sensor. Second time to calculate time T ₁ ′ required for
A calculation unit, and (h) a pulse time interval T ₁ corresponding to the specific angular interval Θ ₁ calculated by the first calculation unit, and a transit time T of the specific angular interval Θ ₁ calculated by the second calculation unit. And a second discriminating unit for discriminating the rotational direction of the rotating body by comparing ₁ 'with the rotational direction detecting device.