KR102228615B1 - Position detecting device - Google Patents

Abstract

At the time the position detection device 10 is started, the arithmetic processing unit 30 corresponds to the first to third angles of rotation that are individually detected by the first to third rotation angle detectors 24 to 28. The absolute position of the rotating shaft 14 is calculated at the start time based on the first to third analog signals. During the rotation of the rotating shaft 14, the current position counter 54 takes as a standard the number of total pulses (TP) corresponding to the absolute position of the rotating shaft 14 at the start time and tells the first rotation angle detector 24. The current absolute position of the rotating shaft 14 is detected by counting the number of forward rotation pulses or reverse rotation pulses corresponding to the first angle of rotation detected by.

Description

Position detection device {POSITION DETECTING DEVICE}

The present invention relates to a position detection device adapted to detect the rotation angle of the rotation shaft and the rotation angle of the output shaft of the speed reduction mechanism when the speed reduction mechanism is connected to the rotation shaft of the rotation body.

Previously, a position detection device for detecting the absolute position of the rotating shaft of the rotating body has been installed on an electric actuator or the like provided with a rotating body such as a motor or the like. This type of position detection device is, for example, Japanese Unexamined Patent Publication No. 2013-164316, Japanese Unexamined Patent Publication No. 2012-145380, Japanese Unexamined Patent Publication No. 2007-078459, Japanese Unexamined Patent Publication No. 2002-513923 (PCT), It is disclosed in Japanese Unexamined Patent Application Publication No. 64-023107 and Japanese Unexamined Patent Application Publication No. 2003-161641.

In Japanese Unexamined Patent Publication No. 2013-164316, Japanese Unexamined Patent Publication No. 2012-145380, and Japanese Unexamined Patent Publication No. 2007-078459, a planetary gear is used in a speed reduction mechanism connected to a rotating shaft of a rotating body. -Rotation-angle detection type position detection devices are disclosed. In Japanese Laid-Open Patent Publication No. 2002-513923 (PCT) and Japanese Laid-Open Patent Laid-Open No. 64-023107, a code recording medium is attached to a rotating shaft of a rotating main body and attached to the output shaft of a speed reduction mechanism connected to the rotating shaft together -Position detection devices attached to the rotation angle detector are disclosed. Japanese Laid-Open Patent Publication No. 2003-161641 discloses a position detecting device in which the data of the detected rotation angle of the rotating shaft is converted into an absolute position after the disclosed orthogonal coordinates are converted into polar coordinates.

However, in the position detection devices of JP 2013-164316, JP 2012-145380, and JP 2007-078459, magnets are attached to the shafts of a plurality of driven gears. And a plurality of sets of rotation angle detectors are attached thereto at relative positions. Therefore, in such position detection devices, there is a disadvantage of increasing the size in the radial direction of the rotating shaft.

Moreover, in the position detection devices of Japanese Laid-Open Patent Publication No. 2002-513923 (PCT) and Japanese Laid-Open Patent Laid-Open No. 64-023107, the code recording medium attached to the rotating shaft serves as an absolute position disk and a specialized scannable thereon The code is deposited by vapor deposition or similar. Therefore, high accuracy is required, and such position detection devices tend to be expensive.

Moreover, in the position detection device of Japanese Laid-Open Patent Application No. 2003-161641, a high-speed arithmetic processing unit is required in order to enable the absolute position to be output in real time.

The present invention was devised from the viewpoint of solving the above-mentioned problems, and provides a position detection device capable of performing an arithmetic process for calculating an absolute position using a small size and low cost, and a low speed arithmetic processing device. Have a purpose.

The present invention provides a position configured to detect the absolute position of the rotating shaft based on the angle of rotation of the rotating shaft and the angle of rotation of the output shaft of the speed reducing mechanism when the speed reducing mechanism is connected to the rotating shaft of the rotating body. It relates to a detection device.

In addition, in order to achieve the above-mentioned object, the position detection device according to the present invention includes first to third rotation angle detectors, an arithmetic processing unit, and a current position detection unit.

The first rotation angle detector is configured to detect a first angle of rotation at pitch intervals of gears substantially coaxially attached to the rotation shaft. The second rotation angle detector is configured to detect a second angle of rotation within one rotation of the rotation shaft. The third rotation angle detector is configured to correspond to a plurality of rotations of the rotation shaft and to detect a third angle of rotation within one rotation of the output shaft.

The arithmetic processing unit is based on the first to third angles of the rotation individually detected by the first to third rotation angle detectors at the start time, the absolute of the rotation shaft at the start time of the position detection device. It is configured to calculate the location. The current position detection unit rotates the rotation shaft when the rotation body is driven based on the first angle of rotation detected by the first rotation angle detector, and the absolute position of the rotation shaft at the start time. While being configured to detect the current absolute position of the rotating shaft.

The gear according to the above configuration, the speed reduction mechanism, and the output shaft are arranged along the axial direction of the rotation shaft, and the first to third rotation angle detectors are arranged around the rotation shaft and the output shaft. As a result, in the position detecting device, the size of the rotating shaft in the radial direction can be reduced.

Moreover, the first rotation angle detector detects a first angle of rotation at a pitch interval of spur gears attached to the rotation shaft. Therefore, there is no need to provide a code recording medium carrying specialized codes as disclosed in Japanese Laid-Open Patent Publication No. 2002-513923 (PCT) and Japanese Laid-Open Patent Laid-Open No. 64-023107. Thus, the position detection device can be produced at reduced cost.

Moreover, only at the start time, based on the first to third angles of the rotation, the arithmetic processing unit calculates the absolute position of the rotation shaft in the start time stop state. Consequently, during the rotation of the rotation shaft, the current position detection unit takes the absolute position of the rotation shaft at the start time as a standard, and the rotation from the first angle of the rotation detected by the first rotation angle detector. It is possible to determine the current absolute position of the shaft in a pseudo manner.

More specifically, the position detection device only functions as an absolute type of rotary encoder at the start time, and then as an incremental type of rotary encoder. In other words, at the start time, the absolute position of the rotary shaft in a stationary state is detected, and then, during rotation of the rotary shaft, of the rotary shaft with respect to its absolute position at the start time. The first angle of rotation corresponding to the amount of motion is detected. In addition, the position of the first angle of rotation with respect to the absolute position at the start time may be determined as the current absolute position of the rotating shaft. As a result, it becomes unnecessary to calculate the absolute position in real time as in Japanese Laid-Open Patent Publication No. 2003-161641, and it is possible to use a low-speed and low-cost calculation processing unit (CPU).

Moreover, in a typical incremental rotary encoder, it is necessary to perform a magnetic pole detection operation and an origin point return operation each time the power supply is turned on and off. On the contrary, in the present invention, since the absolute position of the rotating shaft in a stopped state is detected at the start time, the individual operations described above are unnecessary. As a result, if the position detection device is installed on the electric actuator, it becomes possible to shorten the tact time.

In the above manner, according to the present invention, it is possible to realize a reduction in the cost of the position detection device and to a smaller scale, and to perform arithmetic processing of calculating the absolute position using a low speed computing device with this. .

In this case, the first to third rotation angle detectors are preferably configured in the manner described below.

Initially, the first rotation angle detector is a spur gear attached substantially coaxially with the rotation shaft and composed of a magnetic material, when the spacing between the tooth ends of the spur gear is defined as one cycle. It includes two first magnetic detection elements, which have phases shifted by 90[deg.] to each other and arranged in a face-to-face relationship with the spur gear, and a first bias magnet. In this case, the first magnetic detection elements are individually configured to output first analog signals corresponding to the first angle of rotation and their phases are mutually shifted by 90°.

Thus, when the magnetic field generated by the first bias magnet in the region containing the individual first magnetic detection elements undergoes a change due to the rotation of the spur gear, each of the first magnetic detection elements is a separate first As analog signals, they individually output a change in the magnetic field. Since the individual first analog signals are signals corresponding to the first angle of rotation, the absolute position of the rotating shaft at the start time is based on the first analog signals, etc. In response to the position of ), the operation processing unit can more accurately determine. Moreover, since a commercially available spur gear can be used, compared to the configurations of Japanese Laid-Open Patent Publication No. 2002-513923 (PCT) and Japanese Laid-Open Patent Publication No. 64-023107, a further reduction in the cost of the position detection device Can be realized.

Next, the second rotation angle detector is a ring-shaped second bias magnet attached substantially coaxially with the rotation shaft, when one rotation of the rotation shaft is defined as one cycle, shifted by 90° to each other. And two second magnetic detection elements that have phases and are disposed in opposing relationship to the second bias magnet. In this case, the second magnetic detection elements are individually configured to output second analog signals corresponding to the second angle of rotation, and their phases are shifted from each other by 90°.

Thus, when the magnetic field generated by the second bias magnet undergoes a change in the region containing individual second magnetic detection elements, each of the second magnetic detection elements is individually applied to the magnetic field as separate second analog signals. Print the change. Since the individual second analog signals are signals corresponding to the second angle of rotation, the absolute position of the rotating shaft at the start time is determined by a certain angle within one rotation of the rotating shaft based on the second analog signals, etc. Corresponding to, the arithmetic processing unit can be easily determined.

Moreover, the third rotation angle detector includes a ring-shaped third bias magnet attached substantially coaxially with the output shaft, a phase shifted by 90° to each other when one rotation of the output shaft is defined as one cycle. And two third magnetic detection elements disposed in a facing relationship with the third bias magnet. According to this feature, the third magnetic detection elements are individually configured to output third analog signals corresponding to the third angle of rotation, the phases of which are mutually shifted by 90°.

Thus, when the magnetic field generated by the third bias magnet undergoes a change in the region containing individual third magnetic detection elements, each of the third magnetic detection elements is individually applied to the magnetic field as separate third analog signals. Print the change. In this case, the speed reduction mechanism reduces the rotational speed of the rotating body at a predetermined speed reduction ratio and rotates the output shaft. Therefore, based on the individual third analog signals, the absolute position of the rotating shaft at the start time corresponds to a certain angle within a plurality of rotations of the rotating shaft, so that the arithmetic processing unit can easily determine. .

The position detection device further comprises an interpolator configured to convert the individual first analog signals individually outputted by each of the first magnetic detection elements into two-phase first pulse signals. In this case, the arithmetic processing unit calculates the absolute position of the rotating shaft at the start time based on each of the first to third analog signals individually output by the first to third rotation angle detectors. And outputs a second pulse signal corresponding to the calculated absolute position.

As a result, the current position detection unit easily detects the current absolute position of the rotating shaft based on the first pulse signals output from the interpolator and the second pulse signal output from the arithmetic processing unit. It is possible. Moreover, regardless of the forward or reverse rotation of the rotating shaft, it is possible to ignore the effect of any backlash on the speed reduction mechanism.

In this case, the operation processing unit is configured to transmit the second pulse signal to the current position detection unit as a serial signal including the number of pulses corresponding to the absolute position of the rotating shaft at the start time. I can. According to this feature, a relatively low speed operation processing unit can be used as the operation processing unit, and by transmitting the serial signal to the current position detection unit in the manner of serial communication, it is possible to further reduce the cost of the position detection device. It is possible.

The position detection device further comprises a multiplication circuit configured to generate a multiplication pulse signal obtained by multiplying each of the first pulse signals and output the multiplication pulse signal to the current position detection unit. Can include. In this case, the current position detection unit is configured to preset the number of pulses corresponding to the serial signal at a start time, and during rotation of the rotating shaft, corresponding to the multiplication pulse signal from the preset number of pulses. It may be a current position counter configured to detect the current absolute position of the rotating shaft by counting the number of pulses to be rotated.

According to this feature, using a preset number of pulses as a reference, the current position counter counts the number of pulses corresponding to the multiplication pulse signal, so that the current absolute position of the rotating shaft is easily and very efficient. It is possible to decide. Moreover, by supplying the multiplication pulse signal from the multiplication circuit to the current position counter, the resolution of the current absolute position of the rotating shaft to the current position counter is improved, and the absolute position can be obtained with high accuracy. have.

In this case, the multiplication circuit determines a forward rotation or a reverse rotation of the rotation shaft by comparing the individual first pulse signals, and the multiplied pulse of the determined forward rotation or reverse rotation It can be configured to generate a signal. As a result, the current position counter can accurately determine the current absolute position of the rotating shaft.

The position detection device may further include a rotating body drive control unit configured to rotate the rotating shaft by driving the rotating body when the number of pulses corresponding to the serial signal is preset in the current position counter. Because of that, the rotating body can be operated after such a preset setting, and the absolute position of the rotating shaft during rotation of the rotating shaft can be obtained reliably.

Moreover, in the position detection device according to the present invention, the above-mentioned configuration (also referred to as the basic configuration) can be interchanged with the following configurations.

That is, in order to achieve the above-mentioned object, the position detection device according to the present invention includes, as another first configuration, a first rotation angle detector, a second rotation angle detector, an arithmetic processing unit, and a current position detection unit. do.

The first rotation angle detector is configured to detect a first angle of rotation within one rotation of the rotation shaft. The second rotation angle detector is configured to correspond to a plurality of rotations of the rotation shaft and to detect a second angle of rotation within one rotation of the output shaft. The arithmetic processing unit is the start time of the position detection device based on the first angle of the rotation and the second angle of the rotation individually detected by the first rotation angle detector and the second rotation angle detector at a start time. It is configured to calculate the absolute position of the rotating shaft. The current position detection unit rotates the rotation shaft when the rotation body is driven based on the first angle of rotation detected by the first rotation angle detector, and the absolute position of the rotation shaft at the start time. While being configured to detect the current absolute position of the rotating shaft.

In this case, the first rotation angle detector includes a cylindrical bias magnet substantially coaxially attached to the rotation shaft, and a magnetic detection element arranged in a face-to-face relationship with the bias magnet. The magnetic detection element outputs a serial signal corresponding to the first angle of the rotation to the arithmetic processing unit 30, and the phases of the two-phase corresponding to the first angle of rotation are shifted by 90° to each other. It is further configured to output pulse signals to the current position detection unit.

In this first configuration, the magnetic detection element has both a function of outputting the serial signal to the arithmetic processing unit and a function of outputting the two-phase pulse signals to the current position detection unit as interpolation processing. Moreover, the arithmetic processing unit calculates the absolute position of the rotating shaft at the start time based on the serial signal and the second angle of the rotation detected by the second rotation angle detector. Therefore, according to the first configuration, the position detection device can be produced at a reduced cost because the number of parts of the position detection device is reduced, and the computational load in the operation processing unit is reduced. Moreover, since the cylindrical bias magnet is adopted, the detection accuracy of the first angle of rotation can be improved.

Also in the first configuration, the following beneficial effects can be achieved in a manner similar to the case of the position detection device having the basic configuration described above.

That is, the speed reducing mechanism and the output shaft are disposed along the axial direction of the rotation shaft, and the first rotation angle detector and the second rotation angle detector are arranged around the rotation shaft and the output shaft. As a result, the size of the rotating shaft in the radial direction can be reduced.

Moreover, only at the start time, based on the first angle of rotation and the second angle of rotation, the arithmetic processing unit calculates the absolute position of the rotation shaft in the start time stop state. As a result, during the rotation of the rotating shaft, the current position detection unit takes the absolute position of the rotating shaft at the start time as a standard, thereby facilitating the current absolute position of the rotating shaft from the two-phase pulse signals. It is possible to make decisions in a way and in a pseudo manner. Moreover, regardless of the forward or reverse rotation of the rotating shaft, it is possible to ignore the effect of any backlash on the speed reduction mechanism.

More specifically, the position detection device only functions as an absolute type of rotary encoder at the start time, and then as an incremental type of rotary encoder. As a result, it becomes unnecessary to calculate the absolute position in real time, and it is possible to use a low speed and low cost CPU. If such a position detection device is installed on an electric actuator or similar, it becomes possible to shorten the tact time.

As a result, according to the first configuration, it is possible to realize a reduction in cost and a smaller scale of the position detection device, and to perform arithmetic processing of calculating the absolute position using a low-speed arithmetic processing device at the same time. .

The position detection device may comprise a rotation transmission mechanism configured to transmit a rotational force of the rotational shaft to an input shaft of the speed reduction mechanism, wherein the rotational shaft, the input shaft, and the output shaft are substantially coaxially. Can be arranged. Although the position detection device may be slightly larger in the direction of the direction due to the rotation transmission mechanism, the number of parts of the position detection device is reduced because the first rotation angle detector with the interpolation function is used. Can be. Thus, it is possible to realize a reduction in the cost of the entire device. As the rotation transmission mechanism, various types of rotation transmission mechanisms such as rotation transmission means using belts or other speed reduction mechanisms having a speed reduction ratio of 1 can be preferably adopted.

That is, in order to achieve the above-mentioned object, the position detection device according to the present invention is another second configuration, including first to third rotation angle detectors, a first speed reduction mechanism, a second speed reduction mechanism, A calculation processing unit, and a current position detection unit.

The first rotation angle detector is configured to detect a first angle of rotation within one rotation of the rotation shaft. The first speed reducing mechanism is configured to output and reduce the rotational speed of the rotating shaft. The second speed reduction mechanism is connected to the first speed reduction mechanism, and further reduces the rotation speed of the rotation shaft reduced by the first speed reduction mechanism and transfers the further reduced rotation speed to the output shaft. And an input shaft configured to output. The second rotation angle detector is configured to correspond to a plurality of rotations of the rotation shaft and to detect a second angle of rotation within one rotation of the input shaft. The third rotation angle detector is configured to correspond to a plurality of rotations of the rotation shaft and to detect a third angle of rotation within one rotation of the output shaft.

The arithmetic processing unit is based on the first to third angles of the rotation individually detected by the first to third rotation angle detectors at the start time, the absolute of the rotation shaft at the start time of the position detection device. It is configured to calculate the location. The current position detection unit rotates the rotation shaft when the rotation body is driven based on the first angle of rotation detected by the first rotation angle detector, and the absolute position of the rotation shaft at the start time. While being configured to detect the current absolute position of the rotating shaft.

In this case, the first rotation angle detector includes a cylindrical bias magnet substantially coaxially attached to the rotation shaft, and a magnetic detection element arranged in a face-to-face relationship with the bias magnet. The magnetic detection element outputs a serial signal corresponding to the first angle of the rotation to the arithmetic processing unit 30, and the phases of the two-phase corresponding to the first angle of rotation are shifted by 90° to each other. It is further configured to output pulse signals to the current position detection unit.

In this second configuration compared to the aforementioned position detection device provided with the first and second rotation angle detectors, the position detection device comprises three rotation angle detectors (first to third rotation angle detectors), And two speed reduction mechanisms (a first speed reduction mechanism and a second speed reduction mechanism). Therefore, compared with the first configuration, the number of parts is large and the calculation load in the calculation processing unit is large, resulting in high cost.

However, the second rotation angle detector and the third rotation angle detector individually detect the second angle of rotation and the third angle of rotation corresponding to a plurality of rotations of the rotation shaft, and the calculation processing unit It is possible to calculate the absolute position of the rotating shaft at the start time with high precision using the detected second and third angles of rotation and the like. As a result, compared with ordinary position detection devices, the absolute position can be calculated with high precision and the cost can be reduced. Moreover, since the cylindrical bias magnet is adopted, the detection accuracy of the first angle of rotation can be improved.

Also in the second configuration, the following beneficial effects can be achieved in a manner similar to the position detection device having the basic configuration described above because of the first to third rotation angle detectors.

The above objects, features and advantages of the present invention and other objects, features, and advantages are more apparent from the following description when preferred embodiments of the present invention are considered together with the accompanying drawings shown in the manner of illustrative examples. Will become.

1 is a block diagram of a position detection device according to this embodiment;
Fig. 2 is a schematic configuration diagram of the rotation angle detection mechanism of Fig. 1;
Fig. 3 is an explanatory diagram of the first rotation angle detector of Figs. 1 and 2;
4A is a waveform diagram of output voltage waveforms output from a first magnetic detection element;
4B is a waveform diagram of two-phase first pulse signals transformed by an interpolator from output voltage waveforms;
5A is a waveform diagram of output voltage waveforms output from second and third magnetic detection elements;
5B is a diagram showing the in-phase change lying within one rotation;
6 is a waveform diagram of first pulse signals and forward rotation pulses;
7 is a waveform diagram of first pulse signals and reverse rotation pulses;
8 is a sequence diagram for explaining operations of the position detection device of FIG. 1;
9 is a sequence diagram for explaining operations of the position detection device of FIG. 1;
10 is a block diagram of a position detection device according to a first modified example;
Fig. 11 is a schematic configuration diagram of the rotation angle detection mechanism of Fig. 10;
12A is a waveform diagram of two-phase first pulse signals output from a magnetic detection element;
12B is a waveform diagram of a serial signal output from a magnetic detection element;
13 is a block diagram of a position detection device according to a second modified example; And
14 is a schematic configuration diagram of the rotation angle detection mechanism of FIG. 13.

Preferred embodiments of the position detection device according to the present invention will be described in detail below with reference to the accompanying drawings.

[Configuration of this embodiment]

1 is a block diagram of a position detection device 10 according to this embodiment.

The position detection device 10 includes a rotation angle detection mechanism 16 that detects the rotation angle of the rotation shaft 14 of the rotation body 12, such as a motor or the like, and a controller 18 that controls the drive of the rotation body 12. ).

A speed reducing mechanism 20 is connected to the rotating shaft 14. The speed reduction mechanism 20 reduces the rotational speed of the rotating shaft 14 by 1/N, and causes the output shaft 22 to rotate at this reduced speed. N is the rate of speed reduction of the speed reduction mechanism 20.

The rotation angle detection mechanism 16 includes first to third rotation angle detectors 24 to 28, an arithmetic processing unit 30, and an interpolator 32.

As shown in Figures 1 to 3, the first rotation angle detector 24 with respect to the spur gear 34, spur gear 34 attached substantially coaxially with the rotation shaft 14 Two first magnetic detection elements 36a, 36b arranged facing each other, and a first bias arranged behind the first magnetic detection elements 36a, 36b (on the outer surface in the radial direction of the spur gear 34) It is an angle detector for spur gears composed of magnets 38.

For the spur gear 34, a commercially available spur gear capable of being attached to the rotating shaft 14 can be used. When the spacing (pitch spacing) between the tooth ends of the spur gear 34 is defined as one cycle 360°, the two first magnetic detection elements 36a, 36b are in the circumferential direction of the spur gear 34 It is arranged in a face-to-face relationship with the spur gear 34 with the phases of the spur gears shifted from each other by 90°. The first bias magnet 38 has its N-pole on the radially inner side and its S-pole on the radially outer side of the spur gear 34, respectively, with the first magnetic detection elements 36a, 36b. ) On the rear side.

In addition, with the first rotation angle detector 24, when the magnetic field is generated by the first bias magnet 38 in the region containing the individual first magnetic detection elements 36a, 36b, the magnetic field is the magnetic body. When the spur gear 34 rotates accompanying the rotational motion of the rotating shaft 14, the magnetic field undergoes a change. Each of the first magnetic detection elements 36a, 36b detects a change in the magnetic field as a voltage change, and outputs the detected voltage as a first analog signal.

4A is a waveform diagram of first analog signals (output voltage waveforms) output from the first magnetic detection elements 36a, 36b. In Fig. 4A, the A-phase represents a first analog signal (sine wave signal) output from one first magnetic detection element 36a, and the B-phase represents the first output from the other first magnetic detection element 36b. Represents an analog signal (cosine wave signal). Furthermore, it should be noted that in Fig. 4A, the horizontal axis shows the angle of rotation of the spur gear 34 over time.

As mentioned earlier, since the two first magnetic detection elements 36a and 36b are arranged in a state in phase shifted by 90°, a phase difference of 90° occurs between the A-phase and B-phase. . Moreover, in the A-phase and B-phase, a rotation angle of 360° corresponds to one cycle between the tooth ends of the one cycle spur gear 34. In other words, one cycle corresponds to an electrical angle of 360°. As a result, if the spacing between the tooth ends of the spur gear 34 is defined as one cycle, the first rotation angle detector 24 is at any position (rotation) of the spur gear 34 in one cycle. 1st angle) is detected, and an arbitrary position is output to the arithmetic processing unit 30 and the interpolator 32 as a first analog signal.

Interpolator 32 is an analog voltage comparison type phase interpolation circuit in which a resistor network is used. With respect to the individual first analog signals shown in FIG. 4A, by performing an interpolation method on the predetermined number of divisions S, the first analog signals have a phase difference of 90° output to the controller 18 and shown in FIG. 4B. It is converted into the illustrated two-phase first pulse signals. Compared to the transmission of the second pulse signals from the arithmetic processing unit 30 to the controller 18 in the manner of serial communication, described below, the two-phase The transmission of the first pulse signals takes place at a higher transmission rate.

As shown in Figures 1 and 2, the second rotation angle detector 26 is a ring-shaped second bias magnet 40, a second bias magnet 40 attached substantially coaxially with the rotation shaft 14. ) Is a one-turn rotation angle detector composed of two second magnetic detection elements 42a, 42b arranged in a face-to-face relationship.

The second bias magnet 40 is mounted on the rotating shaft 14 at a position between the spur gear 34 and the speed reduction mechanism 20. In this case, in the ring-shaped second bias magnet 40, one semicircular part of it is assigned to the N-pole, while the other semicircular part of it is assigned to the S-pole. The two second magnetic detection elements 42a, 42b are the rotating shaft 14 and the second bias when one rotation of the rotating shaft 14 and the second biasing magnet 40 is defined as one cycle 360°. These are Hall elements arranged in a face-to-face relationship with the second bias magnet 40 with phases shifted from each other by 90° in the direction of the circumference of the magnet 40.

In addition, with the second rotation angle detector 26, when the magnetic field is generated by the second bias magnet 40 in the region containing the individual second magnetic detection elements 42a, 42b, the rotation shaft 14 When the second bias magnet 40 rotates along with the rotation operation of ), the magnetic field undergoes a change. Each of the second magnetic detection elements 42a, 42b detects a change in the magnetic field as a voltage change, and outputs the detected voltage as a second analog signal.

5A is a waveform diagram of second analog signals output from the second magnetic detection elements 42a and 42b. In Fig. 5A, the letter "A" represents a second analog signal (cosine wave signal) output output from one second magnetic detection element 42a, and the letter "B" is from another second magnetic detection element 42b. It represents the outputted second analog signal (sine wave signal). Moreover, in Fig. 5A, the horizontal axis represents the rotation angle of the rotation shaft 14 and the second bias magnet 40 over time.

5B shows the change in the angle of rotation that lies within one rotation of the rotation shaft 14 and the second bias magnet 40. In this case, the rotation in the counterclockwise direction with respect to 0° (when the B-phase lags with respect to the A-phase) is rotated in a forward rotation, while rotation in the clockwise direction is It is defined as reverse rotation (when the A-phase lags with respect to the B phase).

As mentioned above, since the two second magnetic detection elements 42a and 42b are arranged in a state in phase shifted by 90°, a phase difference of 90° occurs between the A waveform and the B waveform. Moreover, in the A and B waveforms, 360° corresponds to one cycle of the rotating shaft 14 and the second bias magnet 40. In other words, one cycle corresponds to an electrical angle of 360°. Consequently, in the case where one rotation of the rotating shaft 14 and the second bias magnet 40 is defined as one cycle, the second rotation angle detector 26 can be used to determine the rotation shaft 14 and the second bias magnet ( 40) of the arbitrary position (the second angle of rotation) is detected, and the arbitrary position is output to the arithmetic processing unit 30 as a second analog signal.

As shown in Figures 1 and 2, the third rotation angle detector 28 includes a ring-shaped third bias magnet 44, a third bias magnet 44 attached substantially coaxially with the output shaft 22. ) Is a multi-rotational rotation angle detector composed of two third magnetic detection elements 46c and 46d arranged in a face-to-face relationship. In the ring-shaped third bias magnet 44, one semicircular part of it is assigned to the N-pole, while the other semicircular part of it is assigned to the S-pole. The two third magnetic detection elements 46c, 46d are the direction of the circumference of the output shaft 22 and the third bias magnet 44 when one rotation of the output shaft 22 is defined as one cycle 360°. These are Hall elements arranged in a face-to-face relationship with the third bias magnet 44 in a state of having phases shifted from each other by 90°.

In addition, with the third rotation angle detector 28, when the magnetic field is generated by the third bias magnet 44 in the region containing the respective third magnetic detection elements 46c, 46d, the output shaft 22 The magnetic field undergoes a change when the third bias magnet 44 rotates along with the rotational operation of ). Each of the third magnetic detection elements 46c and 46d detects a change in the magnetic field as a voltage change, and outputs the detected voltage as a third analog signal.

Accordingly, as shown in Fig. 5A, the waveforms of the third analog signals output from the third magnetic detection elements 46c and 46d are waveforms having characteristics similar to those of the second analog signals. In addition, in Fig. 5A, the letter "C" represents a third analog signal (cosine wave signal) output output from one third magnetic detection element 46c, and the letter "D" represents another third magnetic detection element 46d. It represents the third analog signal (sine wave signal) output from ). Moreover, since the two third magnetic detection elements 46c and 46d are arranged in a state in phase shifted by 90°, a phase difference of 90° occurs between the C waveform and the D waveform. Moreover, in the C and D waveforms, an electrical angle of 360° corresponds to one cycle of the output shaft 22 and the third bias magnet 44.

However, the speed reducing mechanism 20 reduces the rotational speed of the rotating shaft 14 by 1/N, and causes the output shaft 22 to rotate at this reduced speed. As a result, in the case where one rotation of the output shaft 22 and the third bias magnet 44 is defined as one cycle, the third rotation angle detector 28 outputs an output corresponding to a number of rotations of the rotation shaft 14 An arbitrary position (the third angle of rotation) of the shaft 22 and the third bias magnet 44 is detected, and an arbitrary position is output to the arithmetic processing unit 30 as a third analog signal. Thus, the maximum amount of rotation of the rotating shaft 14 corresponds to the amount within one rotation of the output shaft 22.

The arithmetic processing unit 30 is constituted by a relatively low speed and small scale arithmetic processing device (CPU). The arithmetic processing unit 30 is in the stop state at the start time based on the first to third analog signals from the first to third rotation angle detectors 24 to 28 at the start time of the position detection device 10. Calculate the absolute position of the rotating shaft 14. In addition, when a request from the controller 18 for transmitting the absolute position is made, the arithmetic processing unit 30 transmits a serial signal corresponding to the absolute position to the controller 18 in the manner of serial communication.

The processing occurring in the computational processing unit 30 will now be described in detail. Initially, the arithmetic processing unit 30 converts the output voltage of the first to third analog signals from rectangular coordinates to polar coordinates.

In this case, with respect to the first analog signal, the distance between the tooth ends of the spur gear 34 defines one cycle 360°, and one cycle is divided into S individual segments. Moreover, with respect to the second analog signal, one rotation of the rotating shaft 14 and the second bias magnet 40 defines one cycle 360°, and one cycle is divided into T individual segments. Regarding the third analog signal, one rotation of the output shaft 22 defines one cycle 360°, and one cycle is divided into N individual segments. Moreover, the maximum amount of rotation of the rotating shaft 14 is provided to correspond to the amount within one rotation of the output shaft 22. In addition, with regard to the conversion of rectangular coordinates to polar coordinates to the conversion process (dividing process), a known type of interpolation method can be applied, for example as disclosed in Japanese Laid-Open Patent Publication No. 2002-513923 (PCT).

In this case, if the position of the spur gear 34 is specified by P1 (the first angle of rotation), the number of divisions in the spur gear 34 is specified by S, and the second bias magnet 40 The position is designated by P2 (the second angle of rotation), the number of divisions in the second bias magnet 40 is designated by T, and the position of the third bias magnet 44 is P3 (the third angle of rotation). ), and the number of divisions in the third bias magnet 44 is designated by N, then the amount of rotation TA of the rotating shaft 14 can be expressed by the equation (1) below.

TA = (P1 ÷ T) + INT(P2 × T ÷ 360) × (360 ÷ T)+ (P3 × N)… (One)

The term INT(P2 × T ÷ 360) includes rounding off the decimal places of the calculation result of P2 × T ÷ 360 and makes it in the form of an integer. Moreover, the number of divisions T is the number T of teeth of the spur gear 34, and the number of divisions N is the speed reduction ratio N.

In addition, in the case where the absolute position is transmitted in the manner of serial communication from the arithmetic processing unit 30 to the controller 18, it is assumed that the number of pulses is expressed by PP when the rotating shaft 14 is rotated once. Thus, then the number of pulses (the total number of pulses) TP corresponding to the rotation amount TA is given by the following equation (2).

TP = TA ÷ (360 ÷ PP)… (2)

Therefore, when the calculation result of the number TP of all pulses is rounded to an integer by discarding the fractional part, the following equation (3) is obtained.

TP = INT(TA × PP ÷ 360)… (3)

Using equations (1) and (3), the arithmetic processing unit 30 determines the total number of pulses TP corresponding to the absolute position of the rotating shaft 14 in the stationary state at the start time, and the calculation below it is A serial signal (second pulse signal) corresponding to the calculated number of total pulses TP is transmitted to the controller 18.

In this case, for example, for T = 25, N = 150, P1 = 55°, P2 = 175°, P3 = 156°, PP = 200, and S = 8, then TA = 23575° and TP = 13097.

The controller 18 includes a serial communication unit 50, a multiplication circuit 52, a current position counter (current position detection unit) 54, and a rotating body drive control unit 56.

The serial communication unit 50 performs serial communication with the arithmetic processing unit 30. For example, a transmission request of the total number of pulses TP is transmitted to the arithmetic processing unit 30, and a serial signal (a second pulse signal of the total number of pulses TP) is received in response to the transmission request.

The multiplication circuit 52 multiplies the first pulse signals received from the interpolator 32, and outputs the first pulse signals (multiplication pulse signal) to the current position counter 54 according to the multiplication thereof. In this case, as shown in Figures 6 and 7, for example, by examining the voltage level of the B-phase at a time when the A-phase rises, the multiplication circuit 52 is It discriminates between the forward rotation or the reverse rotation of the pulse signals (corresponding to the rotation shaft 14), thus generating a multiplying pulse signal of the determined forward rotation or reverse rotation.

In the case of Fig. 6, since the voltage level of the B-phase has a low level (L level) at the times when the A-phase rises, the multiplication circuit 52 rotates the first pulse signals of the two-phase forward. A multiplication pulse signal (forward rotation pulse signal) that is determined to be represented by and multiplied by four times by forward rotation is generated. In the case of Fig. 7, since the voltage level of the B-phase has a high level (H level) at the times when the A-phase rises, the multiplication circuit 52 rotates the first pulse signals of the two-phase in the reverse direction. It is discriminated to represent and generates a multiplication pulse signal (reverse rotation pulse signal) multiplied by four times by reverse rotation.

Figures 6 and 7 show that the multiplication circuit 52 generates a multiplication pulse signal multiplied by a single (× 1), a double (× 2), or a quadruple (× 4) multiplying pulse signal from the two-phase first pulse signals. Illustrate one possible example. Moreover, the multiplication circuit 52 is capable of changing (four times multiplied by quadruple -> double multiplied -> multiplication by multiplication) from a multiplication pulse signal having a high scaling factor to a multiplication pulse signal having a low scaling factor.

At the start time of the position detection device 10, the current position counter 54 presets the number TP of the total number of pulses acquired by the serial communication unit 50. Moreover, during the rotation of the rotary shaft 14, a multiplication pulse signal from the multiplication circuit 52 is input to the current position counter 54. Therefore, using the preset total number of pulses TP as a reference, the current position counter 54 counts the number of pulses corresponding to the multiplication pulse signal, whereby the current absolute position of the rotating shaft 14 is pseudo-type. It is detected in a (pseudo manner).

When the total number of pulses TP is preset in the current position counter 54, by supplying the rotating body operation signal to the rotating body 12, the rotating body drive control unit 56 drives the rotating body 12 and rotates Let the shaft 14 rotate.

[Operations of this embodiment]

Next, operations of the position detection device 10 according to the present embodiment will be described with reference to the sequence diagrams shown in Figures 8 and 9. In the description of the operations, if necessary, the descriptions will also be made with reference to the figures 1 to 7.

First, in step S1, the operator turns on the power supply of the controller 18 of the position detection device 10. As a result, in step S2, the controller 18 starts to supply power to the rotation angle detection mechanism 16. As a result, in step S3, the rotation angle detection mechanism 16 receives the supply of power from the controller 18 and starts. In this case, the rotation angle detection mechanism 16 activates only the first to third rotation angle detectors 24 to 28 and the arithmetic processing unit 30.

In the next step S4, the first to third rotation angle detectors 24 to 28 detect the first to third angles of rotation at the current time (at the start time of the position detection device 10), and First to third analog signals corresponding to the first to third angles are output to the arithmetic processing unit 30.

Next, in step S5, the arithmetic processing unit 30 at the start time of the position detection device 10 with the above-described equations (1) and (3) and based on the input first to third analog signals. Calculate the total number of pulses TP corresponding to the absolute position of the rotating shaft 14 at rest. In step S6, the arithmetic processing unit 30 converts the total number of pulses TP into a serial signal (second pulse signal).

In the next step S7, the arithmetic processing unit 30 checks whether or not a transmission request for a serial signal has been issued from the controller 18 or not. If there is no such transfer request, the routine returns to step S4, and the processes of steps S4 to S7 are executed again. Thus, until a notification of the transmission request is received from the controller 18, the rotation angle detection mechanism 16 sequentially executes the detection process for the absolute position of the rotation shaft 14 in the stationary state.

On the other hand, in step S8, if the serial communication unit 50 of the controller 18 has made a transmission request for the serial signal to the arithmetic processing unit 30, then the arithmetic processing unit 30 sends a transmission request (step S7: A notification of YES) is received, and transmission of the serial signal is started to the serial communication unit 50 (step S9). Until a notification of completion of reception of the serial signal is received from the serial communication unit 50 (step S9, step S10: NO), the arithmetic processing unit 30 continues the serial signal transmission process.

When reception of the serial signal is started, in step S11, the serial communication unit 50 performs a judgment process as to whether or not reception of the serial signal has ended. If the reception of the serial signal has not yet been completed (step S11: NO), step S8 is executed again, and a transmission request for the serial signal is performed to the arithmetic processing unit 30.

On the other hand, if the reception of the serial signal is finished (step S11: YES), the serial communication unit 50 outputs a serial signal to the current position counter 54, and in step S12, the current position counter 54 ) Presets the total number of pulses TP corresponding to the input serial signal.

In step S13, when confirming that the total number of pulses TP is set in advance, the serial communication unit 50 transmits a notification of completion of reception to the arithmetic processing unit 30. When the notification of completion of reception is received, the arithmetic processing unit 30 determines whether transmission of the serial signal has ended (step S10: YES), and switches to the operation mode for driving the rotation of the rotating main body 12 (Fig. Step S14 of 9). In the operating mode, the rotation angle detection mechanism 16 operates only the first rotation angle detector 24 and the interpolator 32.

In step S15, when it is confirmed that the total number of pulses TP is preset, the rotating body drive control unit 56 supplies a rotating body operation signal to the rotating body 12 for driving the rotation of the rotating body 12. The rotating body 12 is driven based on the supply of the rotating body operation signal, as a result of which the rotating shaft 14 is rotated (step S16).

In step S17, the first magnetic detection elements 36a, 36b of the first rotational angle detector 24 generate first analog signals corresponding to the first angle of rotation of the rotational shaft 14 during its rotation, individually. And output to the interpolator 32. The first angle of rotation is the rotation of the angle representing the amount of movement of the rotating shaft 14 (the amount of rotation) with respect to the absolute position of the rotating shaft 14 in the stationary state, and the individual first analog signals correspond to the amount of this movement. These are the corresponding analog signals. The interpolator 32 converts the individual first analog signals into two-phase first pulse signals, and outputs each of the converted first pulse signals to the multiplication circuit 52 of the controller 18.

Next, in step S18, the rotation angle detection mechanism 16 determines whether or not the power supply from the power controller 18 has been stopped. If the supply of power has not been interrupted (step S18: NO), the processes of steps S16 to S18 are executed again. More specifically, until the supply from the power controller 18 is stopped (step S18: YES), the rotation angle detection mechanism 16 performs a detection operation of the first angle of rotation, and the control of the two-phase. One pulse signal output operation is repeatedly performed.

On the other hand, in step S19, if the individual first pulse signals are input to the multiplication circuit 52, the multiplication circuit 52 compares the first pulse signals of two-phase, and the first pulse of two-phase Determine whether the signals indicate forward or reverse rotation. Based on this determination result, the multiplication circuit 52 generates a forward rotation multiplication pulse signal (forward rotation pulses) or a reverse rotation multiplication pulse signal (reverse rotation pulses) in which the first pulse signals are multiplied, and The rotation pulses or reverse rotation pulses are output to the current position counter 54.

Using the preset number of total pulses TP as a reference, the current position counter 54 counts the number of pulses of forward rotation pulses or reverse rotation pulses from the total number of pulses TP. More specifically, the current position counter 54 takes the absolute position of the rotating shaft 14 in the stopped state at the start time as the origin point, and the rotation angle of the rotating shaft 14 during its rotation (the amount of movement , The current absolute position corresponding to the amount of rotation) is detected in a pseudo manner, which corresponds to the total number of pulses TP.

Next, in step S20, the controller 18 checks whether or not the power supply of the controller 18 should be turned off. If the power supply is not turned off (step S20: NO), the controller 18 again executes the processes of steps S15, S19, and S20. More specifically, in the position detecting device 10, the process of detecting the absolute position of the rotating shaft 14 is sequentially executed until the power supply of the controller 18 is turned off.

In step S20, if the operator turns off the power supply of the controller 18 (step S20: YES), the individual components inside the controller 18 are stopped (step S21), and the rotation angle detection mechanism 16 ) To stop the power supply (step S18: YES). As a result, the individual components inside the rotation angle detection mechanism 16 are also stopped (step S22).

[Effects of this embodiment]

As described above, according to the position detection device 10 according to this embodiment, the spur gear 34, the speed reduction mechanism 20, and the output shaft 22 are arranged along the axial direction of the rotating shaft 14. Arranged, and by arranging the first to third rotation angle detectors 24 to 28 around the rotation shaft 14 and the output shaft 22, the position detection device 10 in the radial direction of the rotation shaft 14 Can be reduced in size.

Moreover, the first rotation angle detector 24 detects the first angle of rotation at pitch intervals of the spur gears 34 attached to the rotation shaft 14. Therefore, there is no need to provide a code recording medium carrying specialized codes as disclosed in Japanese Laid-Open Patent Publication No. 2002-513923 (PCT) and Japanese Laid-Open Patent Laid-Open No. 64-023107. Thus, the position detection device 10 can be produced at reduced cost.

Moreover, the arithmetic processing unit 30 is based on the first to third angles of rotation at only the start time of the position detection device 10, the absolute position of the rotary shaft 14 in the stationary state at the start time. Calculate As a result, during the rotation of the rotating shaft 14, the current position counter 54 is the current absolute position of the rotating shaft 14 from the first angle of rotation detected by the first rotation of the first rotation angle detector 24. It is possible to determine in a pseudo manner, and the absolute position of the rotating shaft 14 in the stationary state at the start time is taken as standard.

More specifically, the position detection device 10 only functions as an absolute type of rotary encoder at the start time, and then as an incremental type of rotary encoder. In other words, with the position detection device 10, at the start time, the absolute position of the rotating shaft 14 in the stationary state is detected, and then, during the rotation of the rotating shaft 14, its absolute at the start time. The first angle of rotation corresponding to the amount of movement of the rotating shaft 14 with respect to the position (the amount of rotation) is detected. In addition, the position of the first angle of rotation relative to the absolute position at the start time is currently determined as the absolute position of the rotating shaft 14. As a result, it becomes unnecessary to calculate the absolute position in real time as in Japanese Laid-Open Patent Publication No. 2003-161641, and it is possible to use a low-speed and low-cost calculation processing unit (CPU) as the calculation processing unit 30.

Moreover, in a typical incremental rotary encoder, it is necessary to perform a magnetic pole detection operation and an origin return operation each time the power supply is turned on and off. On the other hand, with the position detecting device 10, since the absolute position of the rotating shaft 14 can be detected at the start time, the aforementioned operations are unnecessary. As a result, if the position detection device 10 is installed on an electric actuator or similar, it becomes possible to shorten the tact time.

In the above manner, according to the position detection device 10 according to this embodiment, it is possible to realize a reduction in the cost of the position detection device 10 and a smaller scale, and use a low speed operation processing device with this. Then, it performs arithmetic processing to calculate the absolute position.

Moreover, in the first rotation angle detector 24, the magnetic field generated by the first bias magnet 38 in the region containing the individual first magnetic detection elements 36a, 36b is caused by the rotation of the spur gear 34. In the case of undergoing a change due to, each of the first magnetic detection elements 36a, 36b outputs a change in the magnetic field individually, as individual first analog signals. The individual first analog signals are signals corresponding to the first angle of rotation. Thus, based on the individual first analog signals, the arithmetic processing unit 30 determines that the absolute position of the rotating shaft 14 at the start time corresponds to the position of some numbered tooth of the spur gear 34. It is possible to determine with precision. Moreover, since a commercially available spur gear 34 can be used, compared to the configurations of Japanese Laid-Open Patent Publication No. 2002-513923 (PCT) and Japanese Laid-Open Patent Publication No. 64-023107, the position detection device 10 A further reduction in the cost of can be realized.

Moreover, in the second rotation angle detector 26, when the magnetic field generated by the rotation of the second bias magnet 40 in the region containing the individual second magnetic detection elements 42a, 42b is subjected to a change , Each of the second magnetic detection elements 42a, 42b outputs a change in the magnetic field, individually as separate second analog signals. The individual second analog signals are signals corresponding to the second angle of rotation. Therefore, based on the individual second analog signals, the arithmetic processing unit 30 can easily determine that the absolute position of the rotating shaft 14 at the start time corresponds to a certain angle within one rotation of the rotating shaft 14. It is possible.

Moreover, in the third rotation angle detector 28, when the magnetic field generated by the rotation of the third bias magnet 44 in the region containing the individual third magnetic detection elements 46c, 46d undergoes a change. , Each of the third magnetic detection elements 46c, 46d outputs a change in the magnetic field, individually as separate third analog signals. In this case, since the speed reduction mechanism 20 rotates the output shaft 22 by decelerating the rotational speed of the rotating body 12 at a predetermined reduction ratio N, based on the individual third analog signals, arithmetic processing The unit 30 is capable of easily determining the absolute position of the rotating shaft 14 at the start time corresponding to a certain angle within a number of rotations of the rotating shaft 14.

In addition, since the rotating shaft 14 passes through and transmits through the second bias magnet 40, whereas the output shaft 22 passes through and transmits through the third bias magnet 44, the second rotation angle detector 26 And there is a possibility that the detection accuracy of the second angle of rotation and the third angle of rotation in the third rotation angle detector 28 may be lowered. However, according to the position detection device 10, the first angle of rotation is detected with high precision by the first rotation angle detector 24 using the spur gear 34. As a result, since lowering the detection accuracy of the second angle of rotation and the third angle of rotation is compensated by the high detection accuracy of the first angle of rotation, on the process of calculating the absolute position in the arithmetic processing unit 30 Any effect of it can be suppressed.

Moreover, the interpolator 32 converts the individual first analog signals into two-phase first pulse signals, and the arithmetic processing unit 30 at the start time based on the individual first to third analog signals. The absolute position of the rotating shaft 14 is calculated, and a second pulse signal corresponding to the calculated absolute position is output. As a result, the current position counter 54 is based on the individual first pulse signals output from the interpolator 32, and the second pulse signals output from the arithmetic processing unit 30. It is possible to detect the absolute position easily. Moreover, regardless of the forward or reverse rotation of the rotating shaft 14, it is possible to ignore the effect of any backlash on the speed reduction mechanism 20.

The backlash of the speed reduction mechanism 20 is preferably in the angular range of 360°/(2×n). Moreover, as discussed above, correction of any backlash can be processed according to the software processing performed by the interpolator 32 and the current position counter 54. In this embodiment, by providing a mechanism such as a helical spring that applies torque in a fixed direction with respect to the output shaft 22 of the speed reduction mechanism 20, correction processing by software may be made unnecessary.

Moreover, in the position detection device 10, the arithmetic processing unit 30 serializes the second pulse signals in the form of a serial signal indicating the total number of pulses TP corresponding to the absolute position of the rotating shaft 14 at the start time. Since it is transmitted to the current position counter 54 via the communication unit 50, it is possible to further reduce the cost of the position detection device 10.

Moreover, at the start time of the position detection device 10, the current position counter 54 presets the total number of pulses TP. Moreover, during rotation of the rotating shaft 14, the multiplication circuit 52 generates a multiplication pulse signal based on the first pulse signals. Therefore, using the preset total number of pulses TP as a reference, the current position counter 54 counts the number of pulses corresponding to the multiplication pulse signal, whereby the current absolute position of the rotating shaft 14 is detected. . As a result, the absolute position of the rotating shaft 14 can now be determined easily and very efficiently. Moreover, by supplying a multiplication pulse signal from the multiplication circuit 52 to the current position counter 54, the resolution of the current absolute position of the rotary shaft 14 to the current position counter 54 is improved, and the absolute position is It can be obtained with high accuracy.

Moreover, the multiplication circuit 52 determines the forward or reverse rotation of the rotating shaft 14 by comparing the two-phase first pulse signals, and generates a multiplication pulse signal of the determined forward or reverse rotation. Thus, the current position counter 54 is able to accurately determine the current absolute position of the rotating shaft 14.

Moreover, when the total number of pulses TP is preset in the current position counter 54, the rotating body drive control unit 56 drives the rotating body 12 and causes the rotating shaft 14 to rotate, thereby rotating the rotating shaft. In the meantime, the absolute position of the rotating shaft 14 can be obtained reliably.

[Modifications of this embodiment]

Next, modifications of the position detection device 10 according to the present embodiment (position detection device 10A according to the first modification and position detection device 10B according to the second modification) are shown in Figs. This will be explained with reference to 14. With respect to the position detecting devices 10A, 10B, the constitutional elements thereof which are identical to the constitutional elements of the position detecting device 10 described with reference to the drawings 1 to 9 are indicated by the same drawing numbers, and Detailed descriptions of these features are omitted.

<First modification>

First, the position detection device 10A according to the first modification as a first configuration will be described with reference to figures 10 to 12b.

The position detection device 10A includes a rotation angle detection mechanism 16 comprising a first speed reduction mechanism 60, a second speed reduction mechanism 62, a first rotation angle detector 64, and a second rotation angle detector 66. It differs from the position detection device 10 shown in Figures 1 to 9 as a basic configuration in that it includes ).

The first speed reduction mechanism 60 is a rotation transmission mechanism capable of reducing the rotation speed of the rotation shaft 14 of the rotation body 12 and a second speed reduction mechanism 60 also serves as an output shaft of the first speed reduction mechanism 60. It transmits the reduced rotational speed to the input shaft 68 of the speed reduction mechanism 62. It should be noted that in the first variant, the speed reduction ratio of the first speed reduction mechanism 60 is 1 (one), so that the rotation speed (rotation force) of the rotation shaft 14 is output to the input shaft 68 as it is. .

The first speed reduction mechanism 60 is substantially parallel to the first speed reduction unit 60a provided on one side of the rotation shaft 14, the rotation shaft 14, the input shaft 68, and the output shaft 22. An intermediate shaft 60b extended to, one end of which is connected to the first speed reduction unit 60a, is connected to the other end of the intermediate shaft 60b, and is provided on one side of the input shaft 68 ( 60c) is provided.

The first speed reduction unit 60a meshes with a first gear 70a attached substantially coaxially to the rotating shaft 14 on the input side, and the first gear 70a, and an intermediate shaft 60b on the output side. It is composed of a second gear 72a attached substantially coaxially to one end side of the. The second speed reduction unit 60c meshes with a third gear 70b and a third gear 70b attached substantially coaxially to the other end of the intermediate shaft 60b on the input side and the input shaft 68 on the output side. ) Is substantially coaxially attached to the fourth gear 72b. As described above, since the speed reduction ratio of the first speed reduction mechanism 60 is 1, the respective speed reduction ratios n of the first speed reduction unit 60a and the second speed reduction unit 60c are n Is set to = 1.

The second speed reduction mechanism 62 has substantially the same configuration as the speed reduction mechanism 20 of the position detection device 10. The second speed reduction mechanism 62 is arranged substantially coaxially with the rotary shaft 14 and the rotational force of the rotary shaft 14 is transmitted through the first speed reduction mechanism 60, the input shaft 68, the rotation An output shaft 22 is provided that is arranged substantially coaxially with the shaft 14 and the input shaft 68 and rotates at a rotational speed reduced from the rotational speed of the input shaft 68 by a speed reduction ratio N. Therefore, in the first modification, the total speed reduction ratio of the first speed reduction mechanism 60 and the second speed reduction mechanism 62 is N (= 1 × N).

The first rotation angle detector 64 is a cylindrical bias magnet 74 attached substantially coaxially to the front end side of the rotation shaft 14, arranged in a relationship facing the center of the bias magnet 74. It consists of a magnetic detection element 76. In the bias magnet 74, one semicircular part of it is assigned to the N-pole, while the other semicircular part of it is assigned to the S-pole. Accordingly, the first rotation angle detector 64 is a one-rotation rotation angle detector for detecting a first angle of rotation within one rotation of the rotation shaft 14. The magnetic detection element 76 outputs a serial signal (a signal of the rotation angle data shown in Fig. 12B) corresponding to the first angle of rotation to the arithmetic processing unit 30 in a serial communication manner. Further, the magnetic detection element 76 corresponds to the first angle of rotation and the two-phase digital pulse signals (A-phase and B-shown in Fig. 12A) whose phases are shifted from each other by 90°. Phase first pulse signals) to the multiplication circuit 52.

In other words, according to the first modified embodiment, the magnetic detection element 76 has a function of outputting a serial signal to the arithmetic processing unit 30 and a multiplication circuit ( 52) has both functions. That is, the position detection device 10A according to the first modified embodiment includes the first rotation angle detector 24 and the second rotation angle detector 26 in the position detection device 10 with the first rotation angle detector 64. Exchange. 12B illustrates a case in which the magnetic detection element 76 transmits a serial signal to the arithmetic processing unit 30 during a predetermined time period (serial transmission period).

The second rotation angle detector 66 has a configuration similar to the third rotation angle detector 28 of the position detection device 10 (see Figures 1 and 2). The second rotation angle detector 66 determines a second angle of rotation within one rotation of the output shaft 22 corresponding to a plurality of rotations of the rotation shaft 14 to the third magnetic detection elements 46c, 46d. And outputs analog signals (similar to the third analog signal) corresponding to the detected second angle of rotation to the arithmetic processing unit 30.

The arithmetic processing unit 30 performs sampling of the serial signal from the magnetic detection element 76 at predetermined sampling intervals shown in Fig. 12B. Moreover, the arithmetic processing unit 30 converts the output voltages of analog signals from the third magnetic detection elements 46c and 46d from rectangular coordinates to polar coordinates. Then, the arithmetic processing unit 30 calculates the absolute position of the rotating shaft 14 at the start time based on the output voltages converted into polar coordinates and the serial signal obtained by sampling.

In this case, the arithmetic processing unit 30 calculates the amount of rotation TA of the rotating shaft 14 based on the following equation (4).

TA = P1 + (P3 × N)… (4)

It should be noted that in the first variant, since the spur gear 34 is not used, P1 in equation (4) represents the angle of the rotating shaft 14 (the first angle of rotation).

Moreover, in the first variant, the total number of pulses TP is calculated by the following equation (5).

TP = INT(TA × PP ÷ 360)… (5)

The position detection device 10A according to the first modification can also operate according to the sequence diagrams shown in Figures 8 and 9. In this case, with respect to steps S4, S5, and S17, the two-phase first pulse signals are output directly from the magnetic detection element 76 to the multiplication circuit 52, and the serial signal is the magnetic detection element ( 76) to the arithmetic processing unit 30, analog signals are output from the third magnetic detection elements 46c, 46d to the arithmetic processing unit 30, and the total number of pulses TP is the equations (4) The position detection device 10A operates similarly to the position detection device 10 except that it is calculated by the arithmetic processing unit 30 based on and (5). Therefore, a detailed description of the operation will be omitted.

As described above, in the position detection device 10A according to the first modification, the magnetic detection element 76 of the first rotation angle detector 64 outputs a serial signal to the arithmetic processing unit 30 and performs interpolation processing. It has both functions of outputting two-phase first pulse signals to the multiplication circuit 52 of the controller 18 as. Moreover, the arithmetic processing unit 30 is based on the serial signal, the absolute position of the rotation shaft 14 and the second rotation angle detector 66 (the third magnetic detection elements 46c, 46d) at the start time. The second angle of rotation detected by is calculated. Therefore, in the first modification, the position detection device 10A can be produced at a reduced cost because the number of parts of the position detection device 10A is reduced, and the computational load in the arithmetic processing unit 30 is reduced. Moreover, since the cylindrical bias magnet 74 is adopted, the decrease in magnetic flux density compared to the ring magnet is suppressed, and the detection accuracy of the first angle of rotation can be improved.

Moreover, in the position detection device 10A according to the first modification, also, the following advantages can be obtained in a similar manner in the case of the position detection device 10.

That is, the second speed reduction mechanism 62 and the output shaft 22 are arranged along the axial direction of the rotation shaft 14, and the first rotation angle detector 64 around the rotation shaft 14 and the output shaft 22 ) And the second rotation angle detector 66, the size of the rotation shaft 14 in the radial direction can be reduced.

Moreover, the arithmetic processing unit 30 only calculates the absolute position of the rotating shaft 14 in the stationary state at the start time based on the first and second angles of rotation at the start time. As a result, during the rotation of the rotating shaft 14, the controller 18 (of the current position counter 54) easily calculates the current absolute position of the rotating shaft 14 from the two-phase first pulse signals and It is possible to determine in a pseudo manner, taking the absolute position of the rotating shaft 14 at the start time as a standard.

More specifically, the position detection device 10A only functions as an absolute type of rotary encoder at the start time, and then as an incremental type of rotary encoder. Thus, it becomes unnecessary to calculate the absolute position in real time, and it is possible to use a low speed and low cost CPU. As a result, if such a position detection device 10A is installed on an electric actuator or similar, it becomes possible to shorten the tact time.

Therefore, also according to the first variant, it is possible to realize a reduction in the cost and a smaller scale of the position detection device 10A together with performing the arithmetic processing to calculate the absolute position using the low speed arithmetic processing device. It is possible.

Moreover, also according to the first variant, regardless of the forward or reverse rotation of the rotating shaft 14, the effect of any backlash on the first speed reduction mechanism 60 and the second speed reduction mechanism 62 It is possible to ignore The backlash of the first speed reduction mechanism 60 is preferably in the angular range of 360°/(4×n×n). In the first variant, n = 1. Therefore, it is desirable for the backlash to exist within an angular range of 90°.

The position detection device 10A further comprises a first speed reduction mechanism 60 for transmitting the rotational force of the rotation shaft 14 to the input shaft 68 of the second speed reduction mechanism 62, and the rotation shaft 14 ), the input shaft 68, and the output shaft 22 are arranged substantially coaxially. Although the position detection device 10A becomes slightly larger in the radial direction due to the first speed reduction mechanism 60, the number of parts of the position detection device 10A is used by the first rotation angle detector 64 with an interpolation function. Because it becomes, it is reduced. Thus, it is possible to realize a reduction in the cost of the entire device. In the above description, the case where the first speed reduction mechanism 60 having a speed reduction ratio of 1 is used is described. Alternatively, instead of the first speed reduction mechanism 60, rotation transmission means using various types of rotation transmission mechanisms such as belts can be preferably employed.

<Second Modified Example>

Next, the position detection device 10B according to the second modification as the second configuration will be described with reference to the drawings 13 to 14.

The position detection device 10B includes a rotation angle detection mechanism 16 comprising first to third rotation angle detectors 64,78,80 and a first speed reduction unit 60a of the first speed reduction mechanism 60 And the configuration of the position detection device 10A (see Figs. 10 and 11) according to the first modification in that the respective speed reduction ratio n of the second speed reduction unit 60c is greater than 1. Therefore, the total speed reduction ratio of the first speed reduction mechanism 60 and the second speed reduction mechanism 62 is n × n × N (first speed reduction unit 60a: n; second speed reduction unit 60c) : n; becomes the second speed reduction mechanism 62: N). As a result, the rotational speed of the output shaft 22 becomes a rotational speed reduced from the rotational speed of the rotational shaft 14 by (1/n) × (1/n) × (1/N).

The second rotation angle detector 78 has a configuration substantially similar to the second rotation angle detector 26 (see Figures 1 and 2) of the position detection device 10. However, it should be noted that a second rotation angle detector 78 is provided for the input shaft 68 instead of the rotation shaft 14. That is, in the second variant, a first speed reduction mechanism 60 having a speed reduction ratio n×n is provided between the rotary shaft 14 and the input shaft 68. Thus, the second magnetic detection elements 42a, 42b of the second rotation angle detector 78 correspond to a number of rotations of the rotation shaft 14 and the second rotation within one rotation of the input shaft 68 The angle can be detected.

The third rotation angle detector 80 has a configuration similar to the second rotation angle detector 66 (see Figures 10 and 11) of the position detection device 10A. The third magnetic detection elements 46c, 46d of the third rotation angle detector 80 correspond to a number of rotations of the rotation shaft 14 and determine a third angle of rotation within one rotation of the output shaft 22. Can be detected.

The arithmetic processing unit 30 performs sampling of the serial signal from the magnetic detection element 76 at predetermined sampling intervals shown in Fig. 12B. Moreover, the arithmetic processing unit 30 includes individual analog signals (similar to the second analog signal) and third magnetic detection elements (similar to the second analog signal) corresponding to the second angle of rotation from the second magnetic detection elements 42a, 42b. 46c, 46d), the output voltages of the analog signals (similar to the third analog signal) corresponding to the third angle of rotation from rectangular coordinates to polar coordinates. Then, the arithmetic processing unit 30 calculates the absolute position of the rotating shaft 14 at the start time based on the output voltages converted into polar coordinates and the serial signal obtained by sampling.

In this case, the arithmetic processing unit 30 calculates the amount of rotation TA of the rotating shaft 14 based on the equation (6) below.

TA = P1 + (P2 × n × n) + (P3 × N × n × n)… (6)

In the second variant, since the spur gear 34 is not used, and because the second rotation angle detector 78 is arranged relative to the input shaft 68, in equation (6), P1 is the rotation shaft 14 It should be noted that) represents the angle of (the first angle of rotation) and P2 represents the angle of the input shaft 68 (the second angle of rotation). Moreover, in the second variant, the total number of pulses TP is calculated by equation (5) described above.

In a similar manner in the case of the position detecting device 10A, the position detecting device 10B according to the second modification can also operate according to the sequence diagrams shown in Figures 8 and 9. Also in this case, with respect to steps S4, S5, and S17, the two-phase first pulse signals are output directly from the magnetic detection element 76 to the multiplication circuit 52, and the serial signal is the magnetic detection element. Output from 76 to the processing unit 30, analog signals are output from the second magnetic detection elements (42a, 42b) and the third magnetic detection elements (46c, 46d) to the processing unit 30 The position detection device 10B is similar to the position detection device 10 except that, and the total number of pulses TP are calculated by the arithmetic processing unit 30 based on the equations (5) and (6). Works well. Therefore, a detailed description of the operation will be omitted.

As described above, compared to the position detection device 10A according to the first modification, the position detection device 10B according to the second modification includes three rotation angle detectors (first to third rotation angle detectors). S (64,78,80)), and two speed reduction mechanisms (first speed reduction mechanism 60 and second speed reduction mechanism 62) each having a speed reduction ratio n, N greater than 1 It is equipped. Therefore, compared with the position detection device 10A, the number of parts is large and the computational load in the arithmetic processing unit 30 is large, resulting in high cost.

However, in the second variant, the second rotation angle detector 78 and the third rotation angle detector 80 are provided with a second angle of rotation and a third angle of rotation corresponding to a number of rotations of the rotation shaft 14. It is possible to individually detect and the arithmetic processing unit 30 to calculate the absolute position of the rotating shaft 14 at the start time with high precision using the detected second and third angles of rotation or the like. As a result, compared with ordinary position detection devices, the absolute position can be calculated with high precision and the cost can be reduced. Moreover, in the second modification, since the cylindrical bias magnet 74 is adopted, a decrease in magnetic flux density compared to the ring magnet is suppressed, and the detection accuracy of the first angle of rotation can be improved.

Moreover, since the position detection device 10B according to the second modification is also equipped with the first to third rotation angle detectors 64,78,80, similar beneficial effects to the position detection device 10 can be obtained. I can.

It goes without saying that the present invention is not limited to the embodiments described above, and that various modifications or additional configurations may be adopted therein without departing from the essence and spirit of the present invention disclosed in the appended claims.

Claims (12)

It includes a speed reduction mechanism 20 connected to the rotation shaft 14 of the rotation body 12, and the rotation angle of the rotation shaft 14 and the rotation angle of the output shaft 22 of the speed reduction mechanism 20 A position detecting device 10 configured to detect an absolute position of the rotating shaft 14 on the basis of,
A first rotation angle detector (24) configured to detect a first angle of rotation at pitch intervals of gears (34) substantially coaxially attached to the rotation shaft (14);
A second rotation angle detector (26) configured to detect a second angle of rotation within one rotation of the rotation shaft (14);
A third rotation angle detector (28) configured to correspond to a plurality of rotations of the rotation shaft (14) and to detect a third angle of rotation within one rotation of the output shaft (22);
Of the position detection device 10 based on the first to third angles of the rotation individually detected by the first to third rotation angle detectors 24 to 28 at a time of initiation. An arithmetic processing unit (30) configured to calculate the absolute position of the rotating shaft (14) at a start time; And
The rotation when the rotation body 12 is driven based on the first angle of the rotation detected by the first rotation angle detector 24, and the absolute position of the rotation shaft 14 at the start time. A position detection device (10), comprising a current position detection unit (54), configured to detect a current absolute position of the rotating shaft (14) during rotation of the shaft (14). The method according to claim 1,
The first rotation angle detector 24 is attached substantially coaxially with the rotation shaft 14 and comprises a spure gear 34 made of a magnetic material, a tooth end of the spur gear 34 ) Two first magnetic detection elements arranged in a face-to-face relationship with the spur gear 34 with phases shifted by 90° to each other when the interval between them is defined as one cycle S 36a, 36b, and a first bias magnet 38; And
The first magnetic detection elements 36a, 36b are configured to output, individually, first analog signals corresponding to the first angle of rotation, in which the phases are shifted from each other by 90°, the position detection device 10 . The method according to claim 2,
The second rotation angle detector 26 defines a ring-shaped second bias magnet 40 attached substantially coaxially with the rotation shaft 14, and one rotation of the rotation shaft 14 as one cycle. Two second magnetic detection elements (42a, 42b) arranged in opposing relationship to the second bias magnet (40), with phases shifted by 90[deg.] to each other, if so; And
The second magnetic detection elements 42a, 42b are configured to output, individually, second analog signals corresponding to the second angle of rotation, in which the phases are shifted by 90° with each other, the position detection device 10 . The method of claim 3,
The third rotation angle detector 28 defines a ring-shaped third bias magnet 44 attached substantially coaxially with the output shaft 22, and one rotation of the output shaft 22 as one cycle. Two third magnetic detection elements 46c and 46d disposed in a face-to-face relationship with the third bias magnet 44, with phases shifted by 90° to each other when they are; And
The third magnetic detection elements 46c, 46d are configured to output, individually, third analog signals corresponding to the third angle of rotation, in which the phases are shifted by 90° with each other, the position detection device 10 . The interpolator according to claim 4, configured to convert the individual first analog signals individually outputted by each of the first magnetic detection elements (36a, 36b) into two-phase first pulse signals ( 32);
The operation processing unit 30 is based on each of the first to third analog signals output individually by the first to third rotation angle detectors 24 to 28, the rotation shaft ( 14) and outputs a second pulse signal corresponding to the calculated absolute position; And
The current position detection unit 54 of the rotation shaft 14 based on the first pulse signals output from the interpolator 32 and the second pulse signal output from the arithmetic processing unit 30. Position detection device 10, configured to detect a current absolute position. The method according to claim 5, wherein the operation processing unit 30 receives the second pulse signal as a serial signal including the number of pulses corresponding to the absolute position of the rotating shaft 14 at a start time. Position detection device 10, configured to transmit to detection unit 54. The multiplication circuit according to claim 6, configured to generate a multiplication pulse signal obtained by multiplying each of the first pulse signals, and to output the multiplication pulse signal to the current position detection unit (54). ) Further comprises (52);
The current position detection unit 54 is configured to preset the number of pulses corresponding to the serial signal at a start time, and during rotation of the rotary shaft 14, the multiplication pulse signal from the preset number of pulses Position detection device 10, which is a current position counter configured to detect the current absolute position of the rotating shaft 14 by counting the number of pulses corresponding to. The method of claim 7, wherein the multiplication circuit (52) determines a forward rotation or a reverse rotation of the rotation shaft (14) by comparing the individual first pulse signals, and the determined forward rotation or Position detection device (10), configured to generate the multiplied pulse signal of reverse rotation. The rotating body drive according to claim 7, configured to rotate the rotating shaft 14 by driving the rotating body 12 when the number of pulses corresponding to the serial signal is preset in the current position counter 54. Position detection device (10), further comprising a control unit (56). It includes a speed reduction mechanism 62 connected to the rotation shaft 14 of the rotation body 12, and the rotation angle of the rotation shaft 14 and the rotation angle of the output shaft 22 of the speed reduction mechanism 62 On the basis of, as a position detection device 10A configured to detect an absolute position of the rotating shaft 14,
A first rotation angle detector (64) configured to detect a first angle of rotation within one rotation of the rotation shaft (14);
A second rotation angle detector (66) configured to correspond to a plurality of rotations of the rotation shaft (14) and to detect a second angle of rotation within one rotation of the output shaft (22);
Based on the first angle of rotation and the second angle of rotation individually detected by the first rotation angle detector 64 and the second rotation angle detector 66 at a start time, the position detection device ( An arithmetic processing unit 30 configured to calculate the absolute position of the rotating shaft 14 at the start time of 10A); And
The rotation when the rotation body 12 is driven based on the first angle of the rotation detected by the first rotation angle detector 64, and the absolute position of the rotation shaft 14 at the start time. A current position detection unit 54 configured to detect a current absolute position of the rotating shaft 14 during rotation of the shaft 14,
The first rotation angle detector 64 includes a cylindrical bias magnet 74 attached substantially coaxially to the rotation shaft 14, and a magnetic detection element 76 arranged in a face-to-face relationship with the bias magnet 74. Including, and
The magnetic detection element 76 outputs a serial signal corresponding to the first angle of rotation to the arithmetic processing unit 30, and two corresponding to the first angle of rotation in which phases are shifted by 90° to each other. The position detecting device 10A, further configured to output pulse signals of pseudo-phase to the current position detecting unit 54. 11. The method of claim 10, further comprising a rotation transmission mechanism (60) configured to transmit the rotational force of the rotation shaft (14) to the input shaft (68) of the speed reduction mechanism (62),
The position detection device (10A), wherein the rotating shaft (14), the input shaft (68), and the output shaft (22) are arranged substantially coaxially. It includes a speed reduction mechanism 62 connected to the rotation shaft 14 of the rotation body 12, and the rotation angle of the rotation shaft 14 and the rotation angle of the output shaft 22 of the speed reduction mechanism 62 On the basis of, as a position detection device 10B configured to detect the absolute position of the rotating shaft 14,
A first rotation angle detector (64) configured to detect a first angle of rotation within one rotation of the rotation shaft (14);
A first speed reduction mechanism (60) configured to output and reduce the rotational speed of the rotation shaft (14);
It is connected to the first speed reduction mechanism 60, further decelerates the rotational speed of the rotational shaft 14 decelerated by the first speed reduction mechanism 60, and the further reduced rotational speed. A second speed reduction mechanism 62 comprising an input shaft 68 configured to output to the output shaft 22;
A second rotation angle detector 78 configured to correspond to a plurality of rotations of the rotation shaft 14 and detect a second angle of rotation within one rotation of the input shaft 68;
A third rotation angle detector 80 configured to correspond to a plurality of rotations of the rotation shaft 14 and detect a third angle of rotation within one rotation of the output shaft 22;
Based on the first to third angles of the rotation individually detected by the first to third rotation angle detectors 64,78,80 at the start time, the start time of the position detection device 10B An arithmetic processing unit (30) configured to calculate the absolute position of the rotating shaft (14); And
The rotation when the rotation body 12 is driven based on the first angle of the rotation detected by the first rotation angle detector 64, and the absolute position of the rotation shaft 14 at the start time. A current position detection unit 54 configured to detect a current absolute position of the rotating shaft 14 during rotation of the shaft 14,
The first rotation angle detector 64 includes a cylindrical bias magnet 74 attached substantially coaxially to the rotation shaft 14, and a magnetic detection element 76 arranged in a face-to-face relationship with the bias magnet 74. Including, and
The magnetic detection element 76 outputs a serial signal corresponding to the first angle of rotation to the arithmetic processing unit 30, and two phases corresponding to the first angle of rotation are shifted by 90° to each other. -Position detection device 10B, further configured to output pulse signals of phase to the current position detection unit 54.

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