JPH075190A - Rotation detector for motor - Google Patents

Abstract

PURPOSE:To enhance the resolution of pulse in the detection of rotation while allowing decision of the rotational direction through a simple structure. CONSTITUTION:When the armature 26 of a motor 14 rotates, a pulse is generated from each Hall IC 40, 42 fixed oppositely to a magnet 38 on the armature 26. Two Hall ICs 40, 42 are arranged at an angular interval of 90 deg. and the pulses generated therefrom have a phase difference of a quarter of period. Consequently, the number of pulses per single revolution of the armature 26 is doubled as compared with a case employing a single Hall IC. Furthermore, rotational direction of the armature 26 can be decided by detecting the generation order of pulses from the Hall ICs 40, 42 which is reversed when the rotational direction of the armature 26 is reversed. In the case of a jam protection power window, the count (n) of pulses entering into a dead band can be increased to ensure normal closure of window glass even upon occurrence of lock current and thereby the dead band is halved as compared with the case employing only one Hall IC. This structure positively prevents even a small foreign matter from being caught.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device for an electric motor used for a power window, for example.

[0002]

2. Description of the Related Art A power window includes a so-called jam protection power window which prevents foreign matter from being caught.

In this power window, the window glass rises (moves in the closing direction) and descends (moves in the opening direction) due to normal rotation and reverse rotation of the armature of the DC motor serving as a drive source. When foreign matter is caught between the window glass and the upper edge of the window frame while the window glass is rising, a lock current is generated in the electric motor. Due to the generation of this lock current, the window glass stops rising and immediately descends to prevent foreign matter from being caught.

By the way, when the window glass is completely closed, a lock current is generated in the electric motor. Therefore, at the time of closing the window glass, it is necessary to complete the closing as it is without performing the pinching prevention operation even if the lock current is generated.

Therefore, the motor output shaft of the armature of the electric motor is provided with a magnet having a plurality of poles in which different poles are alternately arranged in the rotation direction, and a Hall IC is mounted on the fixed side of the electric motor in correspondence with the magnet. With the rotation of the armature, a pulse from the Hall IC is transmitted to the ECU (or CP
U).

According to the ECU, the pulse signal is up-counted as the armature rotates in the ascending direction of the window glass,
Conversely, the armature is down-counted as the window glass descends and rotates, and the position of the window glass is detected by the pulse count number.

When a lock current is generated due to the rise of the window glass and the pulse count number does not reach the preset pulse count number n, the pinch prevention operation is performed due to the generation of the lock current, and the pulse is generated. The count number is
After reaching the preset pulse count number n, the trapping prevention operation is not performed even if the lock current is generated. That is, after the pulse count number n, the dead zone is set in which the pinch prevention operation is not performed and the window glass can be normally closed.

[0008]

Here, the larger the pulse count number n is, the narrower the dead zone is, and the prevention of trapping can be optimized.

Therefore, it is conceivable to increase the number of poles of the magnet corresponding to the Hall IC to improve the pulse resolution. However, increasing the number of poles makes the structure complicated,
This also causes an increase in manufacturing cost.

Further, since the foreign matter is trapped only during the ascending of the window glass, the trapping prevention operation may be performed in the ascending process of the window glass, and the trapping prevention operation is not necessary in the descending process of the window glass. Therefore, it is convenient to be able to determine whether the window glass is rising or falling.

Further, in order to obtain the correspondence between the pulse count number and the ascending / descending position of the window glass with respect to the window frame with high accuracy,
It is necessary to reset the pulse count at the upper limit position or lower limit position of the window glass. For this purpose, it is necessary to determine whether the window glass is moving up or down.

[0012] In order to determine whether the window glass is moving up or down, it is necessary to provide a separate means for that. However, providing such means separately complicates the structure and increases the manufacturing cost.

In consideration of the above facts, an object of the present invention is to provide a rotation detecting device for an electric motor, which has a simple structure, improves pulse resolution in rotation detection, and can judge the rotation direction.

[0014]

According to a first aspect of the present invention, there is provided a rotation detecting device for an electric motor corresponding to a plurality of magnets provided on an armature of the electric motor and having different poles alternately arranged in the rotating direction. Then, each magnetic sensor has a plurality of magnetic sensors provided on a fixed portion of the motor, and each magnetic sensor emits a pulse as the armature rotates, and the magnetic sensors are arranged to generate a phase difference between the magnetic sensors. And pulse generating means arranged at intervals in the rotation direction of the armature.

[0015]

In the rotation detecting device for an electric motor according to the first aspect of the present invention, a pulse is emitted for each magnetic sensor as the armature of the electric motor rotates.

Since there is a phase difference in the pulses between the magnetic sensors, the number of pulses with respect to the amount of rotation of the armature is twice the number of magnetic sensors as compared with a single magnetic sensor. For example, with two magnetic sensors. If so, the number of pulses will be doubled,
Increases pulse resolution.

Further, the order of pulse generation in the magnetic sensor differs depending on whether the armature is forward or reverse.
When there are two magnetic sensors, the magnetic sensor and the second magnetic sensor, if the pulse is generated in the first magnetic sensor after the pulse is generated in the first magnetic sensor due to the normal rotation of the armature, the second is generated depending on the reverse rotation of the armature. A pulse is generated in the first magnetic sensor after the pulse is generated in the magnetic sensor, and the generation order is different, so that it is possible to determine whether the armature is forward or reverse.

Further, the enhancement of the pulse resolution can be achieved without increasing the number of poles of the magnet, and the determination of the armature as to whether the armature is normal or reverse can be achieved without providing a separate means for that, and has a simple structure. I'm done.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a motor rotation detection device according to the present invention applied to a jam protection power window of an automobile will be described with reference to FIGS.

As shown in FIG. 2, in the jam protection power window 10, a DC motor 14 is provided inside the vehicle door 12. A drum 16 rotatably driven by the DC motor 14 is connected to the DC motor 14.
Both ends of the wire 18 are spirally wound around. A carrier plate 20 is fixed to an intermediate portion of the wire 18, and the forward and backward rotation of the drum 16 causes the carrier plate 20 to move up and down the guide rail 22 to raise a window glass 24 attached to the carrier plate 20 (door. It moves in the closing direction) and descends (moves in the door opening direction).

In the electric motor 14, as shown in FIG. 1, in the intermediate portion of the motor output shaft 28 of the rotor (armature) 26,
A worm 30 is formed, a helical gear 32 meshes with the worm 30, and these are housed in a housing 34 (FIG. 3) that constitutes a fixed portion of the electric motor. An output gear 36 is provided coaxially with the helical gear 32 and protrudes outside the housing 34.
Are engaged and connected, and the normal rotation (rotation in the direction of arrow A) and the reverse rotation (rotation in the direction of arrow B) of the armature 26 cause the drum to rotate normally (rotation in the direction of arrow A) and reverse rotation (rotation in the direction of arrow B). To do.

At the base end of the motor output shaft 28, an annular magnet 38 is provided on the outer periphery thereof. Magnet 38
Are different poles alternately arranged in the rotating direction of the armature 26,
There are multiple poles. In this embodiment, the number of poles is two.

Corresponding to the magnet 38, two Hall ICs constituting a magnetic sensor are provided outside the housing 34 in the radial direction of the motor output shaft 28 (first Hall IC).
40, second hall IC 42). Hall IC 40, 42
Embedded in the substrate 50, as shown in FIG.
Is built in the case 44. As shown in FIGS. 4, 7, and 8, the case 44 is fixed to the outer surface of the housing 34, and one end of the case 44 has the female screw portion 4 on the wall of the housing 44.
7 is screwed and fastened with screws 48, and projections 45 (shown in FIG. 7) of the wall of the housing 44 are inserted into the crimping holes 46 on the one end side and the other end side to be heat crimped.

As shown in FIG. 4, the first hall IC 40 is located at an angular interval θ with respect to the second hall IC 42 in the reverse direction of the armature 26. In this embodiment, the angular interval θ is 90 °. As shown in FIG.
When the first Hall IC 40 emits a pulse along with the normal rotation of the armature 26, the second Hall IC 40 is delayed by a quarter cycle of this pulse and
Hall IC 42 emits a pulse, and Hall IC 40, 4
Pulses are emitted one after another every two, and the emitted pulses are sent from the terminal 52 (FIG. 4) on the substrate 50 to an ECU (or CPU; control device) not shown. EC
As shown in FIG. 3, the electric motor 14 is connected to U together with the Hall ICs 40 and 42 via a relay connector 56. Reference numeral 54 in FIG. 3 denotes a pulse signal line 54, and 58
Is a motor power supply line.

When the armature 26 reverses, the order of pulse generation is reversed, and after the second Hall IC 42 issues a pulse, the first Hall IC 40 issues a pulse with a delay of 1/4 cycle of this pulse.

That is, at the time of normal rotation of the armature 26,
The pulse of the first Hall IC 40 rises first, then
The pulse of the second Hall IC 42 rises. Also, the first
The pulse of the Hall IC 40 falls first, then the second
The pulse of the Hall IC 42 falls.

When the armature is reversed, the second hall IC
42 pulse rises first, then the first Hall IC
40 pulses rise. In addition, the second hall IC42
Pulse falls first, then the first Hall IC 40
Pulse falls.

In the ECU, the pulse of the first Hall IC 40 and the pulse of the second Hall IC 42 are added together,
It is counted up in accordance with the rotation of the armature 26 in the closing direction of the window glass or the rotation of the armature 26 in the ascending direction (normal rotation), and the counting is down in the rotation of the armature 26 in the opening direction of the window glass or the rotation of the window glass descending direction (reverse rotation). That is, the pulse counts of the pulses emitted by the first hall IC 40 are 1, 3, 5, ...
The pulse count number of the pulse generated by C42 is 2,
4, 6, ...

The pulse count number is as shown in FIG.
It corresponds to the ascending / descending position of the window glass 24.

The control of the ECU when the window glass 24 is raised will be described. The pulse count number at the lower limit position of the window glass 24 is 0, and the pulse count number at the upper limit position of the window glass 24 is n + 1.

When a lock current (overcurrent) is generated in the electric motor 14 in the process of raising the window glass 24, if the pulse count number does not reach n, the lock current is generated.
The window glass 24 stops the ascent and immediately descends to perform a trapping prevention operation. Foreign matter such as fingers is caught in the window glass 24 and the upper edge 2 of the window frame.
When it is sandwiched between the motor 5 and the motor 5, a lock current is generated in the electric motor 14, but the foreign matter can be removed without difficulty by the above-mentioned clamping operation. In addition, the trapping prevention operation can be performed in various operations such as only stopping the rise of the window glass 24.

When a lock current is generated in the electric motor 14 in the ascending process of the window glass 24, if the pulse count number reaches n, the window glass 24 does not perform the trapping prevention operation even if the lock current is generated. . At the time of closing the window glass 24, the window glass 24 receives resistance between the window glass 24 and the upper edge 25 of the window frame to generate a lock current, but the closing operation of the window glass 24 is normally performed. That is, after the pulse count number n, the dead zone 60 is set such that the pinch prevention operation is not performed and the closing operation is normally performed even if the lock current flows.

The ECU detects the order of pulse generation to determine whether the armature 26 is rotating normally or reversely. Since it is not necessary to perform the trapping prevention operation when the window glass 24 is descending, the circuit for the trapping prevention operation can be omitted when it is determined to be reverse, which is convenient. Furthermore, whether the window glass 24 has reached the rising limit end by judging whether the armature 26 is rotating normally or reversely,
It is possible to determine whether the lower limit end has been reached, and the pulse count number can be reset at the upper limit position and the lower limit position. For example, even if the pulse count number does not reach n + 1 when the window glass 24 is completely closed, or even if the pulse count number exceeds n + 1, the pulse count number is reset to n + 1 at the rising limit position of the window glass 24. Thereby, the correspondence between the pulse count number and the ascending / descending position of the window glass 24 with respect to the window frame can be accurately obtained.

Next, the operation of the above embodiment will be described. With the rotation of the armature 26 of the electric motor 14, the Hall IC 40,
Every 42, a pulse is emitted. Hall IC 40, 42
There is a phase difference between the pulses, and the number of pulses with respect to the rotation amount of the armature 26 is twice as large as that of a single Hall IC, and the pulse resolution is high.

Therefore, the dead zone 60 is reduced to ½ when the number of Hall ICs is two, compared to when it is one. By making the dead zone 60 smaller, it is possible to guarantee the normal closing and closing of the window glass by that amount, and it is possible to reliably perform the pinch prevention operation even for smaller foreign matter.

Further, since the pulse generation order of the Hall ICs 40 and 42 is different depending on whether the armature 26 is normal or reverse, it is possible to judge whether the armature 26 is normal or reverse by detecting this difference.

Further, the improvement of the pulse resolution can be achieved without increasing the number of poles of the magnet 38, and the determination of the forward or reverse rotation of the armature 26 can be achieved without providing a separate means for that, which is simple. The structure is enough.

Further, when the Hall IC element is exposed in the housing, foreign matter such as conductive brush powder or flying solder may be attached between the leads to cause malfunction or failure. If this happens, the service life will be shortened. According to the above configuration, the Hall ICs 40, 4
The element of No. 2 is shielded from the inside of the housing 34 (inside the electric motor) by the wall of the case 44 and the wall of the housing 34 and is not exposed in the housing 34, and such a problem does not occur.

In the above embodiment, as shown in FIG. 5, the pulse phase difference between the Hall ICs 40 and 42 corresponds to 50% of the pulse width, which is particularly preferable. There is no limitation as long as the 42 pulses are not synchronized. The phase difference can be changed by changing the angle interval θ. However, if you consider the assembly error of each part, the pulse width is 5% to 95%.
A phase difference within the range is preferable.

In the above embodiment, the number of poles of the magnet 38 is two, but the number of poles is not limited to two, and an even number of poles such as four poles and six poles is also possible. The angular interval θ that makes the phase difference of the pulse between the Hall ICs 1/4 cycle is 45 in the case of 4 poles.
Is 60 °, and in the case of 6 poles, it is 30 °. That is, the angular interval θ = 180 / the number of poles (even number).

Further, although the number of Hall ICs is two in the above embodiment, the number of Hall ICs is not limited to this, but only the angular interval θ.
2 to place Hall ICs on each side
More than one is possible. In this case, the pulse count number is twice the number of Hall ICs, and the pulse resolution is further enhanced.

Next, a second embodiment will be described with reference to FIGS. 9 and 10. In this embodiment, two Hall ICs 40 and 42 are used.
The case 70 with a built-in unit is fixed to the outer surface of the housing 74 by a stopper 72. One end of the stopper 72 is fixed to the outer surface of the housing 34, and the other end of the stopper 72 sandwiches the case 70 with the wall of the housing 74.

If the stopper 72 is made of a magnetic material such as Fe, the magnetic lines of force of the magnet 38 act outward in the radial direction of the magnet 38 toward the stopper 72, and between the stopper 72 and the magnet 38. Intervening Hall ICs 40, 42
Ensures the detection of the magnetic field of the magnet 38 even if the wall of the case 70 and the wall of the housing 74 block the magnet 38 in the housing 74.

Other constitutions and effects are similar to those of the first embodiment. The present invention is not limited to the above embodiments, but various modifications can be made. For example, in each of the above-described embodiments, the rotation detection device of the electric motor applied to the jam protection power window has been described. Instead, it can be applied to other devices that detect a rotational position, a rotational angle, a rotational speed, and the like. Further, the electric motor is not limited to the DC electric motor, and may be another electric motor.

Further, in the above embodiment, the pulse generating means is composed of the Hall IC and the magnetic sensor and the signal processing circuit are made into a single component. However, the present invention is not limited to this, and the magnetic sensor and the signal processing circuit are provided. Can be configured as a separate part. Also, various magnetic sensors are possible.

Further, in the above embodiment, the Hall IC is built in the case and mounted outside the housing. However, even if the Hall IC is provided inside the housing, the function and effect of the present invention are not reduced. Various mounting means can be used.

[0047]

As is apparent from the above, the present invention has a simple structure and improves the pulse resolution in rotation detection.
It is also possible to determine the rotation direction.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts showing a rotation detection device for an electric motor according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a power window to which the rotation detection device for an electric motor according to the first embodiment is applied.

FIG. 3 is an overall perspective view of an electric motor.

4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is a time chart of pulses.

FIG. 6 is a diagram showing a vertical position of a window glass corresponding to a pulse count number.

FIG. 7 is a plan view showing the electric motor with no Hall IC attached.

FIG. 8 is a plan view showing the electric motor with a Hall IC attached.

FIG. 9 is a perspective view showing an electric motor according to a second embodiment without a Hall IC attached.

FIG. 10 is a perspective view showing a motor with a Hall IC mounted according to a second embodiment.

[Explanation of symbols]

 14 electric motor 26 armature 38 magnet 34 housing (fixed part) 40, 42 hall IC (magnetic sensor)

Claims (1)

[Claims] 1. A magnet having a plurality of poles provided on an armature of an electric motor and having different poles alternately arranged in the rotating direction, and a plurality of magnetic sensors provided on a fixed portion of the electric motor corresponding to the magnets, each magnetic Each sensor emits a pulse in accordance with the rotation of the armature, and a pulse generation means is provided in which the magnetic sensors are arranged at intervals in the armature rotation direction in order to generate a phase difference in the pulses between the magnetic sensors. A rotation detection device for an electric motor, characterized in that