JP5573253B2 - Motor with built-in sensor - Google Patents

Description

  The present invention relates to a sensor built-in motor provided with a sensor for controlling a rotation angle of an output shaft.

  As a motor for opening / closing control of a gas flow rate control valve and the like and driving control of various devices such as a mirror mounted on a vehicle, a motor provided with a control device for controlling the rotation angle of an output shaft is used. In such a motor, it is required to accurately control the rotation angle of the output shaft based on the input signal.

Therefore, conventionally, for example, when a DC motor is used as the motor, a positioning sensor as shown in FIGS. 5 and 6 is used to control the rotation angle.
The positioning sensor 1 includes a contact 3 that rotates synchronously with the output shaft 2 of the motor, and a carbon film resistor 4 formed on a circular locus of the contact 3.

  Then, by utilizing the fact that the resistance Ra between the terminals 5 and 6 and the resistance Rb between the terminals 6 and 7 change as the contact 3 rotates, the contactor is detected by detecting the voltage difference Ra / Rb. 3 is detected, and when the detected value of Ra / Rb reaches a value corresponding to the preset rotation angle of the output shaft 2, the motor is stopped.

  Incidentally, a motor using this type of positioning sensor is also disclosed in, for example, Patent Document 1 below.

  When a stepping motor is used as the motor, the stepping motor can control the rotation angle with high accuracy by the number of energized pulses. Therefore, first, the stepping motor is rotated to the origin side. Thus, a method is adopted in which the origin is detected (initialization control) in order to abut against a predetermined position and then a preset number of pulses are energized.

  Since the above-described control is an open loop control in which only a set number of pulses are energized, when more accurate position control is required, the one shown in FIGS. 5 and 6 is used. The same positioning sensor is used in combination, and closed loop control for feedback from the positioning sensor is performed.

JP 7-280506 A

  By the way, in the motor using the conventional positioning sensor 1, the actual rotation angle of the output shaft 2 depends on the variation in the resistance in the circumferential direction of the carbon film resistance, the width of the contact portion in the contact 3, and the like. There is a drawback that an error of about ± 1 ° occurs between the rotation angle obtained from the detected Ra / Rb.

  For this reason, although it can be used as it is for driving an object for which strict angle control is not required, for example, a high feedback angle control such as a fuel gas flow control valve is required. It is necessary to perform closed loop control provided with the above, and there is a problem that the control system becomes complicated.

  In addition, when the stepping motor is used, a large load is applied to the reduction gear train every time initialization control is performed. Therefore, a control method with a lighter load is desired from the viewpoint of extending the service life. It was.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the motor with a built-in sensor which can perform high rotation angle control with a simple structure.

In order to solve the above problem, the motor with a built-in sensor according to claim 1 detects a rotation angle of a stepping motor, a reduction gear train meshed with a rotation shaft of the stepping motor, and an output shaft of the reduction gear train. And a control means for controlling the rotation of the stepping motor. The sensor is formed in advance on a plurality of contacts fixed to the output shaft and a rotation trajectory of these contacts. A plurality of conductive patterns that are electrically connected to the contact at a set angle θ, and the control means is configured to perform initialization when the angle θ ₁ for rotating the output shaft is smaller than the minimum angle of θ. After carrying out the origin of the output shaft, the number of pulses corresponding to the angle θ ₁ is energized to the stepping motor and the angle θ ₂ for rotating the output shaft is When greater than each of the theta is energized the pulse to the stepping motor rotates the output shaft, and at the theta ₂ within the said sensor and the SL conduction of the contact of the maximum angle of the theta After receiving the signal, the stepping motor is energized with the number of pulses corresponding to the angle (θ ₂ −θ).

  According to the motor with a built-in sensor according to claim 1, since a conductive pattern that conducts the contact at the set angle θ is used as the sensor, an error caused by a resistance variation or the like as in a conventional positioning sensor. Will not occur. In addition, since a stepping motor is used as the motor, only the angle equal to or larger than the set angle θ needs to be pulse-controlled. Therefore, the rotation angle of the output shaft can be controlled with high accuracy by open loop control.

Moreover, since the set angle θ can be used as the conventional origin position, the conventional initialization control is necessary only when the stepping motor is rotated by an angle θ ₁ that is less than the set angle θ. When the rotation control is performed up to the angle θ ₂ exceeding the angle θ, the above initialization control can be made unnecessary. As a result, the load acting on the reduction gear train can be reduced, and the life can be further extended.

1 is a perspective view showing a state in which an output shaft and a contact are disassembled, which is an embodiment of a sensor built-in motor according to the present invention. It is a perspective view which shows the state which assembled the output shaft etc. of FIG. It is a top view which shows typically the sensor part of FIG. FIG. 4 is a development view of the conductive pattern of FIG. 3. It is a top view which shows the conventional positioning sensor typically. FIG. 6 is a principle diagram when the position detection of FIG. 5 is performed.

  1 to 4 show an embodiment of a motor with a built-in sensor according to the present invention, and reference numeral 10 in the figure denotes a casing of the motor with a built-in sensor. For the sake of visual convenience, the upper half of the casing 10 is omitted.

  The inside of the casing 10 is divided into upper and lower spaces by a partition plate 10a. A stepping motor 11 is incorporated in the lower space, and a reduction gear train 12 is provided in the upper space. Here, an opening is formed in the plate 10a at a position above the stepping motor 11, and the first stage gear 12a in the reduction gear train 12 is fixed to the rotating shaft 11a of the stepping motor 11 protruding from the opening. ing.

  Further, the second and subsequent gears 12b to 12d are rotatably supported by the partition plate 10a. And the sensor board | substrate 14 is arrange | positioned under the output shaft 13 with which the gear 12d of the last stage was integrally molded.

  The sensor substrate 14 is formed with a circular opening 14a into which the output shaft 13 is inserted at the center, and an arc-shaped first having the output shaft 13 and the center axis aligned with the outer periphery of the opening 14a. The conductive pattern 15 is formed. The first conductive pattern 15 is formed in a continuous arc shape.

  A rectangular second conductive pattern is provided at two locations on the outer peripheral side of the first conductive pattern 15 and at a position where the output shaft 13 is rotated 90 ° from the reference position and a position rotated 180 °. 16a and 16b are formed. Here, the second conductive patterns 16 a and 16 b are formed so that the output shaft 13 and the central axis coincide with each other and are positioned on an arc having a larger diameter than the first conductive pattern 15.

  Further, the second conductive patterns 16a and 16b are arranged on the outer peripheral side, and the output shaft 13 is rotated at 90 ° with respect to the reference position, and at a position rotated at 270 °, the rectangular third Conductive patterns 17a and 17b are formed. The third conductive patterns 17a and 17b are also formed so that the output shaft 13 and the central axis coincide with each other and are positioned on an arc having a larger diameter than the second conductive patterns 16a and 16b.

The second and third conductive patterns 16a, 16b, 17a, and 17b are formed on the surface of the sensor substrate 14 with a continuous arc-shaped conductive pattern similar to the first conductive pattern 15, in which the conductive patterns 16 a, 16b, 17a, are places excluding portions of 17b formed by being covered with the resist film. As a result, the second conductive patterns 16a and 16b and the third conductive patterns 17a and 17b are electrically connected. Lead lines 18, 19, and 20 to a control board (control means) (not shown) are connected to the first to third conductive patterns 15, 16a, and 17a, respectively.

  On the other hand, a conductive piece 21 made of a conductive metal is attached to the end face of the gear 12d formed integrally with the output shaft 13 facing the sensor substrate 14. The conductive piece 21 is formed by integrating three contacts 22 a, 22 b, and 22 c, and the position where the contact 22 a is the same distance as the first conductive pattern 15 with respect to the central axis of the output shaft 13. Further, the contact 22b is fixed at the same distance as the arc of the second conductive patterns 16a and 16b, and the contact 22c is fixed at the same distance as the arc of the third conductive patterns 17a and 17b.

  The sensor substrate 14, the first to third conductive patterns 15, 16a, 16b, 17a and 17b, and the first to third conductive patterns 15, 16a, 16b, 17a and 17b are arranged so as to be in contact with each other. A sensor for detecting the rotation angle of the output shaft 13 is configured by the conductive piece 21 having the contactors 22a to 22c.

  In the motor with a built-in sensor having the above-described configuration, when the contacts 22a to 22c of the conductive piece 21 are electrically connected to the first conductive pattern 15, the second conductive pattern 16a, and the third conductive pattern 17a, respectively, the control device A signal indicating that the rotation angle of the output shaft 13 is 90 ° is generated. Further, when the contacts 22a and 22b of the conducting piece 21 are conducted to the first conductive pattern 15 and the second conductive pattern 16b, respectively, a signal that the rotation angle of the output shaft 13 is 180 ° is generated.

  Further, when the contacts 22a and 22c of the conductive piece 21 are electrically connected to the first conductive pattern 15 and the third conductive pattern 17b, respectively, a position detection signal indicating that the rotation angle of the output shaft 13 is 270 ° is sent to the control device. Be emitted.

When a signal for rotating the output shaft 13 by a predetermined angle θ ₁ is input to the control device by the stepping motor 11, if the angle θ ₁ <90 ° is _first satisfied, the output shaft 13 by initialization is used. Then, the stepping motor 11 is energized with the number of pulses corresponding to the angle θ ₁ . Thereby, the output shaft 13 can be rotated by the angle θ ₁ with a high accuracy of one step angle in the stepping motor 11.

In contrast, the output shaft 13 the angle theta ₂ is 90 ° to rotate the, is greater than 180 ° or 270 ° is energized the pulse to the stepping motor 11 to rotate the output shaft 13, each said conductive strip After the contacts 22a to 22c are connected to each other, the control device receives the position detection signal of 90 °, 180 ° or 270 °, and then the angle (θ ₂ −90 °), (θ ₂ −180 °) Alternatively, the stepping motor 11 is energized with the number of pulses corresponding to (θ ₂ −270 °).

As described above, according to the sensor built-in motor, the sensor for detecting the position of the output shaft 13 is incorporated in the casing 10, and the contacts 22 a to 22 c are set as the sensor at the setting angles of 90 °, 180 °, and 270 °. Since the first to third conductive patterns 15, 16 a, 16 b, 17 a, and 17 b to be conducted are used, an error caused by resistance variation or the like does not occur unlike the conventional positioning sensor.

  In addition, since a stepping motor is used as the motor, it is only necessary to perform pulse control only on the set angles of 90 °, 180 °, and 270 ° or more, so that the control device can be configured by a digital circuit and open. Even with a simple control device based on loop control, the rotation angle of the output shaft can be controlled with high accuracy.

In addition, since the set angles 90 °, 180 °, and 270 ° can be used as the conventional origin position, the initialization control is not required when the rotation is controlled to the angle θ ₂ that exceeds the set angle. be able to. As a result, the load acting on the reduction gear train 12 can be reduced, and the life can be further extended.

  In the above embodiment, the first to third conductive patterns 15, 16 a, 16 b, 17 a, and 17 b are formed on the sensor substrate 14, and the set angles are 90 °, 180 °, and 270 °. Although only this was demonstrated, it is not restricted to this, The position and angle of a setting angle can be changed suitably by increasing / decreasing the number and position of a conductive pattern.

DESCRIPTION OF SYMBOLS 11 Stepping motor 12 Reduction gear train 13 Output shaft 14 Sensor board 15 1st conductive pattern 16a, 16b 2nd conductive pattern 17a, 17b 3rd conductive pattern 21 Conductive piece 22a-22c Contactor

Claims (1)

A stepping motor, a reduction gear train meshed with the rotation shaft of the stepping motor, a sensor for detecting the rotation angle of the output shaft of the reduction gear train, and a control means for controlling the rotation of the stepping motor. Become
The sensor includes a plurality of contacts fixed to the output shaft, and a plurality of conductive patterns formed on a rotation locus of the contacts and electrically connected to the contacts at a preset angle θ. ,
When the angle θ ₁ for rotating the output shaft is smaller than the minimum angle of θ, the control means performs the origination of the output shaft by initialization and then sets the number of pulses corresponding to the angle θ ₁ with energizing the stepping motor, when the angle theta ₂ which rotates the output shaft is greater than each of the theta is energized the pulse to the stepping motor rotates the output shaft, said from the sensor theta ₂ And the stepping motor is energized with the number of pulses corresponding to the angle (θ ₂ −θ) after receiving the conduction signal of the contact with the maximum angle of θ and motor.

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