JP3428943B2 - Rotary body position detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the position of a rotating body.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting the rotational position of a rotating body, a method using an encoder that calculates a signal according to the rotation of the rotating body is known. In this case, for example, the encoder detects the rotation position (rotation angle from the reference rotation position) of the rotating body by counting the signal according to the rotation of the rotating body. By the way, for example, a drive device is known in which a rotating body driven by a drive means such as a motor is connected to a slide device to slide the device by the rotation of the rotating body. In such a drive device, for example, the device is slid in the vertical direction between the upper limit position and the lower limit position by rotating the rotating body for several hundreds to several thousand revolutions. In this case, in order to detect the current position of the device from the rotation amount of the rotating body, it is necessary to detect the number of rotations and the rotating position of the rotating body from the reference position.

Here, the meaning of the terms used in this specification will be explained. The term “rotational position” is used to indicate the rotational position (rotational angle from the reference rotational position) of the rotating body during one rotation. The term "reference position" is used to indicate the "rotation position" at the end when the rotating body is rotated in one direction or the other direction. For example, the rotating body and the slide device are connected to slide the device. In the case of a driving device that moves, it indicates the "rotation position" of the rotating body when the device is located at the origin position (moving end or the like). Further, the term "position of the rotating body" means the rotational movement distance of the rotating body from the "reference position", that is, the number of rotations after which the rotating body is located from the "reference position" of the rotating body. Is used to indicate. For example, in the case of a drive device that slides an apparatus by connecting a rotating body and a slide device, the current position with respect to the origin of the apparatus is shown.

[0004]

In such a drive device, when the power source is cut off in a state in which the rotating body is located at a position other than the "reference position", the "position of the rotating body" is detected when the power source is turned on again. There is a need. In this case, the "position of the rotating body" can be detected by returning the rotating body to the "reference position". However, the method of returning the rotating body to the “reference position” and detecting the “position of the rotating body” takes time. Therefore, conventionally, the memory of the encoder or the like holds the position data indicating the “position of the rotating body”. Here, when a memory that requires a power source to hold data is used, the position data stored in the memory is erased when the voltage of an auxiliary power source such as a battery or a capacitor drops. Even if a non-volatile memory is used to prevent the position data from being erased due to a drop in the auxiliary power supply, when the rotating body rotates while the power is cut off, the "rotary body position" and the non-volatile memory are retained when the power is turned on again. An error occurs with the stored position data. In this case, position control cannot be performed accurately. Therefore,
It is an object of the present invention to provide a position detecting device for a rotating body that can reliably detect the “position of the rotating body” in a short time.

[0005]

A first invention of the present invention for solving the above-mentioned problems is a position detecting device for a rotating body as described in claim 1. In the position detecting device for a rotating body according to claim 1, the rotating body rotates in conjunction with the rotation of the rotating body,
Set so that the rotation ratio of the rotating body to the rotation is different.
At least two rotating members, and each rotating member
Rotation position detecting means for detecting the rotation position of
A body position detecting device, wherein each rotating member is positioned at a predetermined position.
The rotation position detection means has a rotation detector
It has steps, and each rotating member rotates in conjunction with the rotation of the rotating body.
After stopping, the detection means is rotated and
The position of the rotating body is detected by detecting the rotational position of the position detection unit of the rolling member.
To detect. In the position detecting device for a rotating body according to claim 1, the "reference position" of at least two rotating members that are set to rotate in association with the rotation of the rotating body and have different rotation ratios with respect to the rotation of the rotating body, respectively. “Rotation position” is detected. With this, it is not necessary to perform the process of returning the rotating body to the “reference position”, so that the “position of the rotating body” can be detected in a short time. Further, since the current position of the rotating body is detected, the position data is not erased and an error does not occur between the current position of the rotating body and the position data as in the case where the position data is held in the memory. The "position of the rotating body" can be detected.
Further, rotation position detection means for may be detected "rotational position" in the one rotation of the rotating member, it is possible to detect the "position of the rotary body" in shorter time. A second aspect of the present invention is a position detecting device for a rotating body as described in claim 2. Position of the rotating body according to claim 2.
In the detection device, the rotational position detection means is the rotation of the detection means.
It has a signal output means for outputting a signal according to the rotation. this
According to the configuration of the rotation position detecting means it can be simplified.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment of a position detecting device 1 for a rotating body of the present invention. Figure 2
FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 for explaining the relationship between the rotating members 2c-4c and the position detectors 7A-7C. A first rotating member 2c is provided on the rotating shaft 2 that is a rotating body to be detected in a direction perpendicular to the longitudinal direction of the rotating shaft 2. A first tubular member 30 is rotatably supported on the rotary shaft 2 via a bearing 3d. The first tubular member 30 has a first tubular portion 3a. The first tubular portion 3a is provided at one end of the first tubular portion 3a.
A first disk portion 3b is provided in a direction perpendicular to a. A second rotating member 3c is provided on the circumferential portion of the first disc portion 3b in a direction perpendicular to the first disc portion 3b. The gear 5f for the first tubular member 30 of the reduction gear 50 is attached to the other end of the first tubular portion 3a. In addition, the first cylindrical member 30 has a bearing 4d.
The second tubular member 40 is rotatably supported via. The second tubular member 40 has a second tubular portion 4a. A second disc portion 4b is provided at one end of the second tubular portion 4a in a direction perpendicular to the second tubular portion 4a. A third rotating member 4c is provided on the circumferential portion of the second disc portion 4b in a direction perpendicular to the second disc portion 4b. The gear 5e for the second tubular member 40 of the reduction gear 50 is attached to the other end of the second tubular portion 4a. First rotating member 2c and second rotating member 3
Position detecting portions 7A to 7C are provided at predetermined positions on the end faces of the c and the third rotating member 4c (on the left side in the drawing), as shown in FIG. In the present embodiment, the position detectors 7A to 7C of the first to third rotating members 2c to 4c.
Are formed of a reflective material having a higher light reflectance than other portions.

The first rotating member 2c and the second rotating member 3
c, a rotation position detecting means 12 is provided at a position facing the third rotation member 4c. Rotational position detection means 12
Has a third tubular member 60, photoelectric sensors 8A to 8C, a motor 9, and a first encoder 10. The third tubular member 60 is rotatably supported by the rotary shaft 2 via a bearing 6d. The third tubular member 60 has a third tubular portion 6a. A position detection arm 6b is provided at one end of the third tubular portion 6a, and the third tubular portion 6a is provided.
A gear 6c is provided at the other end of the. Gear 6c
Mesh with a gear 9b connected to the motor shaft 9a of the motor 9. The motor 9 is provided with a first encoder 10. The position detection arm 6b includes
The photoelectric sensor 8A is located at a position where it can face the position detectors 7A to 7C provided on the end faces of the first to third rotating members 2c to 4c.
~ 8C are provided. The photoelectric sensors 8A to 8C are composed of a light emitting device and a light receiving device, and detect the position detecting units 7A to 7C when the light receiving level of the light receiving device becomes high.

The reduction gear 50 is mounted with a support shaft 5a rotatably supported by a bearing 5d and a predetermined space in a direction perpendicular to the longitudinal direction of the support shaft 5a about the support shaft 5a. Gear 5b and gear 5
have c. One of the support shafts 5a (on the left side in the drawing) has a longitudinal groove formed on the surface of the support shaft 5a by a predetermined length, and engages with the second tubular member gear wheel 5e. In addition, the gear 5c is the first tubular member 3
It meshes with the 0 gear 5f. The gear 5b is the rotary shaft 2
It meshes with the gear 11 attached to the. The gear 11 meshes with the gear 15 on the other hand. Gear 15
Is connected to the second encoder 14 via the shaft 13. The reduction gear 50 allows the first rotating member 2c,
The rotation ratios of the second rotary member 3c and the third rotary member 4c with respect to the rotation of the rotary shaft 2 are set to be different.

Normally, the rotary shaft 2 is driven by a drive motor or the like, and an output signal is output from the second encoder 14 according to the rotation of the rotary shaft 2. Second encoder 14
The position of the rotary shaft 2 is detected by the output signal of. Then, the drive motor and the like are controlled so that the position of the rotary shaft 2 becomes a predetermined position. After turning off the power of the drive motor,
When the power is turned on again, the current position of the rotary shaft 2 is detected by the rotational position detector 12.

Next, the operating principle of the position detecting device 1 for the rotating body will be described. In the following, the reduction gear 50
The gear ratio of the gear 5f to the gear 11 is 1/10, and the gear ratio of the gear 5e to the gear 11 is set to 1/100. That is, the first rotating member 2c rotates at the same speed as the rotating shaft 2. The second rotation member 3c rotates once when the reduction gear 50 rotates the first rotation member 2c 10 times. The third rotating member 4c is
When the second rotation member 3c makes 10 rotations by the reduction gear 50, it makes one rotation. The "reference position" is 0 degree. The position detectors 7A to 7C provided on the first rotating member 2c, the second rotating member 3c, and the third rotating member 4c change as shown in FIG. 4, for example. Here, 0 degrees to less than 36 degrees is "0 area", 36 degrees to less than 72 degrees is "1 area", 72 degrees to less than 108 degrees is "2 area", 108 degrees to 144 degrees. "3 areas" between 1 and 1
"4 areas" between 44 degrees and less than 180 degrees, 180 degrees-
"5 area" between less than 216 degrees, "6 area" between 216 degrees and less than 252 degrees, "7 area" between 252 degrees and less than 288 degrees, "8 areas between 288 degrees and less than 324 degrees" Area "The area between 324 degrees and less than 360 degrees is defined as" 9 area ". FIG. 4A shows the case where the rotary shaft 2 rotates 180 degrees after one rotation from the “reference position”. At this time,
The position detector 7A is located at a position of 180 degrees. In addition, the position detection unit 7B is "1 area" between 36 degrees and less than 72 degrees.
It is in. The position detector 7C is in the "0 area" between 0 degree and less than 36 degrees. Therefore, it can be determined that the position of the rotary shaft 2 is the position of 180 degrees (1.5 rotations) after one rotation. Similarly, in FIG. 4B, the position of the rotary shaft 2 is as follows because the position detector 7A is in 180 degrees, the position detector 7B is in "9 area", and the position detector 7C is in "0 area". It can be determined that the position is 180 degrees (9.5 rotations) after 9 rotations. In FIG. 4C, the position detector 7A is 180 degrees, the position detector 7B is "1 area",
Since the position detector 7C is in the "1 area", the position of the rotary shaft 2 is 180 degrees after 11 rotations (11.
It can be determined that it is 5 rotations. In FIG. 4D, the position of the rotary shaft 2 is rotated 98 times because the position detecting unit 7A is in 180 degrees, the position detecting unit 7B is in "8 area", and the position detecting unit 7C is in "9 area". It can be determined that the position is 180 degrees behind. In this way, the position detector 7A-
The position of the rotary shaft 2 can be determined by detecting the "rotation position" of 7C.

Next, a method of determining the "rotational position" of the rotational position detecting means 12 will be described with reference to FIG. Below, the case where the position detection units 7A to 7C are in the state shown in FIG. 2 will be described. With the rotating shaft 2 stopped, the position detection arm 6b, that is, the photoelectric sensor 8 is driven by the motor 9.
A-8C is rotated to detect the "rotation position" of the position detection units 7A-7C. Here, it is assumed that the first encoder 10 outputs 100 pulses per one rotation as shown in FIG. This means that one cycle of pulse output corresponds to the rotational movement of the photoelectric sensors 8A to 8C by 3.6 degrees. The photoelectric sensor 8 for detecting the position detecting units 7A to 7C when the position detecting units 7A to 7C are at the positions shown in FIG.
The output signals of A to 8C have the waveforms shown in FIG. Since the position detection units 7A to 7C are reflection units, photoelectric sensors 8A to 8C are provided.
When C detects each of the position detecting units 7A to 7C, the light receiving level of C becomes high. When the light receiving level exceeds a predetermined value, the output signals of the photoelectric sensors 8A to 8C are turned on. When the light receiving level becomes equal to or lower than a predetermined value, the output signals of the photoelectric sensors 8A to 8C are turned off. The rotational position detecting means 12 includes photoelectric sensors 8A to 8A.
Until the output signal of 8C turns on (position detection units 7A to 7C
By counting the number of pulses of the first encoder 10 (until is detected) by a counter (built in the first encoder 10), the "rotational position" of the position detection units 7A to 7C is calculated, and the position detection unit The position of the rotary shaft 2 is calculated from the "rotation position" of 7A to 7C. Position detector 7A
2 to 7C are in the state shown in FIG. 2, the position detector 7A detects 21.6 degrees from the signal waveform shown in FIG.
Is 32.4 degrees, and the position detection unit 7C detects that it is in the "rotation position" of 349.2 degrees. That is, the position detector 7
B is “0 area” (32.4 degrees is 0 degree or more and less than 36 degrees), and the position detection unit 7C “9 area” (349.2 degrees is
324 degrees or more and less than 360 degrees) is detected. As a result, it is determined that the position of the rotary shaft 2 is “the position of 21.6 degrees after 90 rotations”. First encoder 10
Outputs a position signal corresponding to the calculated position of the rotary shaft 2.

In the present embodiment, the "position of the rotating body" is calculated by the first encoder 10, but a means for calculating the "position of the rotating body" based on the signal from the first encoder 10 is separately provided. It may be provided. Further, the rotational position detecting means 12 is not limited to the reflective type as in the present embodiment, but may be a translucent type. In this case, the position detectors 7A to 7C
Is a light transmitting part. Further, the rotational position detecting means 12 uses a photoelectric switch, and the position detecting portions 7A to 7A are optically detected.
Although C is detected, it is sufficient that the “rotation position” of the rotating member can be detected by a magnetic detection method, a contact detection method, or the like.
Further, the shape of the rotating member is not limited to the disk shape. Further, the connecting means for connecting the rotating body and the rotating member is not limited to the gear. Further, the connection ratio (rotation ratio) of the connecting means is not limited to the above description. Further, the shape of each member is not limited to the shape shown in FIG. 1, and may be the shape shown in FIG. 3, for example. In FIG. 3, the first rotating member 2c is shown at 102c and the second rotating member 2c is shown at 102c.
Of the rotating member 3c of 103 and 1 of the third rotating member 4c.
It corresponds to 04c. Further, the position detection arm 6b is 106
In b, the photoelectric sensors 8A to 8C correspond to 108A to 108C. In this case, the rotating members 102c to 104c can be formed in a disc shape. Therefore, for example, the rotating members 102c to 104c can be formed of a reflective material, and a non-reflective material or a hole can be provided in the position detection unit. At this time, the photoelectric sensors 108A to 108C detect the position detection unit due to the low light reception level. Further, the case where the rotating member has three stages has been described, but any number of stages may be used as long as it has two or more stages. In addition, in the present embodiment, the position of the rotary shaft 2 during normal operation is detected by the second encoder 14, but it can also be detected by the first rotary member 2c and the rotary position detector 12. For example, a plurality of position detecting portions are arranged in a circle at a predetermined interval on the inner peripheral side of the position detecting portion 7A of the first rotating member 2c. In addition, a photoelectric sensor is provided at a position of the position detection arm 6b on the inner peripheral side of the photoelectric sensor 8A, facing the plurality of position detection units, and, for example, pulse output is counted based on the output signal of the photoelectric sensor. Then, the position of the rotary shaft 2 is calculated. In this case, the second encoder 14 can be omitted. In addition, in the present embodiment, as the auxiliary signal generation means for detecting the "rotational position" of the position detection units 7A to 7C, the first
Although the encoder 10 is used, the auxiliary signal generating means may be constituted by the first rotating member 2c and the rotational position detecting means 12. For example, a plurality of position detection units are arranged in a circle on the inner peripheral side of the position detection unit 7A of the first rotating member 2c. The photoelectric sensor is provided on the position detection arm 6b on the inner peripheral side of the photoelectric sensor 8A, at a position facing the plurality of position detection units. Then, based on the output signal of the photoelectric sensor and the output signals of the photoelectric sensors 8A to 8C, for example, the pulse output is counted to detect the "rotational position" of the position detection units 7A to 7C. In this case, the first encoder 10 can be omitted.

[0013]

As described above, according to the first and second aspects of the invention, the "position of the rotating body" can be easily detected.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

2 is a cross-sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view of another embodiment of the present invention.

FIG. 4 is a diagram illustrating the operating principle of the present invention.

FIG. 5 is a diagram showing a signal waveform of each part.

[Explanation of symbols]

1 Rotating body position detector 2 rotation axes 2c First rotating member 3c Second rotating member 4c Third rotating member 9 motors 10 First encoder 12 Rotational position detection means 14 Second encoder 30 First tubular member 40 Second tubular member 50 reduction gear 60 Third tubular member

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Claims (2)

(57) [Claims] 1. At least two rotating members that rotate in association with rotation of the rotating body and are set to have different rotation ratios with respect to the rotation of the rotating body, and a rotation position for detecting a rotating position of each rotating member. Position of the rotating body with detection means
In the position detection device, each rotating member has a position detecting portion at a predetermined position, and the rotational position detecting means has rotatable detecting means,
The member has stopped after rotating in conjunction with the rotation of the rotating body
In this state, the detection means is rotated to detect the position of each rotating member.
Rotating body that detects the rotational position of the part to detect the position of the rotating body
Position detection device. 2. The rotating body detecting device according to claim 1 , wherein the rotational position detecting means is a signal according to the rotation of the detecting means.
Position detecting device for rotating body having signal output means for outputting
Place