JP2017227456A - Origin position detection method and origin position detection device of operation mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform origin position detection on a mechanism by a single detector, inexpensively and accurately.SOLUTION: An origin position detection device comprises a movable body 8 which rotates and operates a rotary plate 6 for blocking a light, and which is operated in direct-acting operation along an axial line of the rotary plate 6. A path 7 for transmitting a light is provided on a plate surface of the rotary plate 6. The movable body 8 has a transmission path 14 for transmitting a light to the rotary plate 6. A light source 13 for radiating a light to the transmission path 14 of the movable body 8 is provided on a set portion in a midway of a movement path of the movable body 8. A light detector 11 is provided on the other side of the rotary plate 6 on a side opposite to the movable body 8, and detects a light which is transmitted by the transmission path 14 and passes through the path 7 for transmitting the light of the rotary plate 6. An origin position detection method detects a position where, a position where the light is transmitted by the transmission path 14 and a path where the light is transmitted on the rotary plate 6 match, is detected as an origin position P of the movable body 8.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an origin position detection method and an origin position detection apparatus for an operation mechanism such as a linear motion mechanism and a speed reduction mechanism using a motor.

As a typical positioning mechanism using a motor, a linear motion mechanism using a ball screw as shown in FIG. 6 is known. In this linear motion mechanism, a ball screw shaft 103 is connected to a rotating shaft 101 of a motor 100 via a coupling 102. A ball screw nut attached in a table 104 is screwed onto the ball screw shaft 103. As the motor 100 rotates, the ball screw shaft 103 rotates, and the table 104 is linearly moved along the guide rail 105. Move in the direction.
Such a linear motion mechanism requires an operation for detecting the origin position when the power is turned on. The origin position detection operation is performed by providing the light shielding plate 106 on the table 104 and shielding the sensor 107 (sensor 1) provided at the origin position of the guide rail 105 by the light shielding plate 106. That is, when the table 104 moves in the direction of the origin and reaches the origin position, the sensor 107 is shielded from light by the light shielding plate 106, and this is detected as the origin position.
When the origin position is detected only by the sensor 107 provided on the mechanism, a photoelectric sensor or a magnetic sensor is generally used. In the case of a photoelectric sensor, the position of the moving body is detected by detecting whether light passes or blocks between the light emitting element and the light receiving element. The transition of light passing and blocking changes in an analog manner, and the threshold level for determining ON / OFF of the signal is affected by temperature and other external factors. As a result, when a photoelectric sensor is used for the sensor 107, a detection error of ± 20 μm occurs, and the variation in the origin position detection corresponding to two pulses occurs in the movement amount of the stepping motor. (As an example, a stepping motor having a resolution of 500 pulses on a ball screw shaft with a lead of 10 mm).

When positioning with a linear motion mechanism, a servo motor or a stepping motor is used. When high reliability is required, a servo motor equipped with an encoder is used. For the origin position detection in the linear motion mechanism, accurate origin position detection can be performed by the logical product of the sensor 107 provided on the mechanism and the zero-phase output (Z-phase output) of the encoder output signal.
On the other hand, when realizing highly accurate positioning at low cost, an open loop control stepping motor may be used. For detecting the origin of the rotating shaft 101, a slit rotating plate 108 having a slit in a part of a rotating plate provided on the rotating shaft 101, a photoelectric sensor 109 (sensor 2), and the like are generally used. In this case, the origin position is detected by the logical product of the controller 110 based on the detection values of the sensors 1 and 2 provided on the mechanism for detecting the origin position in the linear motion mechanism.

Japanese Patent Laid-Open No. 02-292190

In such a linear motion mechanism using a ball screw shaft using a stepping motor, in order to perform highly accurate return to origin, the origin position detection sensor 107 (sensor 1) on the mechanism and the origin on the rotation axis of the stepping motor are used. Two sensors of the sensor 109 (sensor 2) for detecting (Z phase) are required.
In order to avoid the influence of detection errors that occur in the origin position detection sensor on the mechanism, it is necessary to take the logical product of the output of the sensor 1 and the output of the sensor 2 that detects the origin (Z phase) on the rotation axis. In addition to the need to calculate the sensor output by using two sensors, the problem of cost and installation space for sensors, mounting man-hours, wiring, etc. is also a problem to be solved.

  The present invention provides an origin position detection method and origin position detection apparatus for an actuation mechanism that can detect the origin position on an actuation mechanism such as a linear motion mechanism and a speed reduction mechanism using a motor with a single detector. With the goal.

In order to solve the above-mentioned problems, the present invention provides a moving body that rotates a rotating plate that shields light and is linearly operated along the axis of the rotating plate, and transmits light to the plate surface of the rotating plate. A transmission path is provided, a transmission path for transmitting light toward the rotating plate is provided in the moving body, and light is irradiated toward the transmission path of the moving body at a set point in the movement path of the moving body. A light source is provided, disposed on the other side of the rotating plate opposite to the moving body, and provided with a light detector that detects light transmitted through the path through which light transmitted by the transmission path passes. It is to detect the position where the position where the light is transmitted through the transmission path and the path where the light of the rotating plate passes is detected as the origin position of the moving body.
In addition, the present invention provides a rotating plate that is rotated, a moving body that is operated in a linear motion, an axial direction of the rotating plate, a path through which light passes, and a light path that is provided in the moving body and transmits light. Disposed on the other side of the rotating plate on the opposite side of the moving body, and a light source for irradiating light toward the transmission path of the moving body. And a light detector that detects light that has passed through a path through which light transmitted through the transmission path passes light, a position for transmitting light through the transmission path, and light from the rotation board. The optical detector is provided that detects the position where the path passing through coincides with the origin position of the moving body.

According to the present invention, a rotating plate that shields light is rotated, a moving body that is linearly operated along the axis of the rotating plate is provided, a path through which light passes is provided on the plate surface of the rotating plate, The moving body is provided with a transmission path that transmits light toward the rotating plate, and a light source that irradiates light toward the transmission path of the moving body is provided at a setting position in the middle of the moving path of the moving body, A light detector is provided which is disposed on the other side of the rotating plate opposite to the moving body and detects light transmitted through the path through which light transmitted through the transmission path passes, and light is transmitted through the transmission path. Since the position where the position where the light is transmitted and the path through which the light of the rotating plate passes is detected as the origin position of the moving body, the origin position can be detected by one light source and a photodetector, respectively. The number of points can be reduced and the size can be reduced.
According to the present invention, the rotating plate that is operated to rotate, the moving body that is operated to move linearly, the axial direction of the rotating plate, the path through which light passes, the moving body that is provided with light A light source that radiates light toward the transmission path of the moving body, and the other side of the rotating plate on the opposite side of the moving body. A light detector that detects light that has passed through a path through which the light transmitted through the transmission path passes, and a position for transmitting the light through the transmission path; and Since the photodetector for detecting the position where the path through which light passes coincides as the origin position of the moving body is provided, the origin position can be detected by one light source and a photodetector, respectively. Reduction and downsizing can be achieved.

It is a perspective view which shows the state away from the origin in embodiment of the rotation axis | shaft and mechanism origin position detection apparatus in case the signal source used for an origin detection is a light emitting element. It is a side view of FIG. FIG. 1 shows a rotating plate used in FIG. 1, (a) is a perspective view, and (b) is a longitudinal sectional view of (a). It is a side view which shows the detection part of FIG. 1A and 1B show a process leading to origin detection of the origin position detection device of FIG. 1, wherein FIG. 1A is a front view of a rotating plate showing a signal path and a position of a receiving unit, and FIG. . 1 shows the process leading to the origin detection of the origin position detection device of FIG. 1, (a) is a front view of the rotating plate in a state where the signal path and the position of the receiving unit are coincident, and (b) is a state of being still away from the receiving unit. It is a side view. (C) is the elements on larger scale of (b). 1 shows a detection position in the process of detecting the origin position of the origin position detection device of FIG. 1, (a) is a front view of the rotating plate in a state where the signal path and the position of the receiving unit are coincident, and (b) is a signal source and a receiving unit. FIG. It is a conceptual diagram which shows the linear motion mechanism using the conventional ball screw.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 5 show an embodiment in which light is used as a detection target in a linear motion mechanism, and a light emitting element such as an LED is used as a signal source.
1 and 2, reference numeral 1 denotes a motor such as a stepping motor. A driver 2 and a controller 3 are electrically connected to the motor 1 via lead wires and the like, and are rotated by the driver 2 at a set speed. A ball screw shaft 5 is directly connected to the rotating shaft of the motor 1 via a coupling 4.
A rotating plate 6 having a plate surface 6 a formed with a hole 7 is attached to the ball screw shaft 5 at the end of the motor 1, and a moving body 8 such as a table screwed to the ball screw shaft 5 is attached. Has been. The moving body 8 includes a ball screw nut 5a screwed onto the ball screw shaft 5, and the moving body 8 moves together with the ball screw nut 5a. The moving body 8 is mounted via a slide block 10 on a traveling guide rail 9 arranged in parallel with the moving direction of the moving body 8. The slide block 10 is a slider block mounted on the lower surface of the moving body 8, and has an opening 10a formed in a U-shaped cross section on the lower surface side. By assembling the opening 10 a to the guide rail 9, the slide block 10 travels along the guide rail 9 and causes the moving body 8 to move linearly.

  As shown in FIGS. 3A and 3B, the rotary plate 6 is fixed concentrically to the ball screw shaft 5 via a cylindrical shaft portion 6b provided at the center portion. It is rotationally driven with the rotation of 5. An optical sensor 11 serving as a detector that detects a light beam that passes through the hole 7 when it coincides with the hole 7 at a position having the same radius as the hole 7 of the rotating plate 6 is attached to the fixed portion. On the other hand, the base plate 12 to which the guide rail 9 is attached has a signal source 13 serving as a light source using a light emitting element such as an LED that emits light toward the moving body 8 when the moving body 8 is at the origin position. Is provided.

  The moving body 8 is provided with a light pipe 14 serving as a light transmission path for irradiating light toward the hole 7 of the rotating plate 6 through the light from the signal source 13. The light pipe 14 is bent in an L shape with one end facing the lower surface and the other end facing the rotating plate 6, and is a pipe that allows light to pass through when it coincides with the signal source 13. The light pipe 14 is set so that the light from the signal source 13 coincides with the light pipe 14 and the hole 7 of the rotating plate 6 when the moving body 8 is at the origin position. The signal path is set so that the light passing through 14 is irradiated to the optical sensor 11 through the hole 7.

Next, a method of detecting the origin position by the origin position detection device will be described with reference to FIGS. 5A to 5C.
FIG. 5A shows a state where the signal path between the signal source 13 of the light emitting element and the optical sensor 11 of the receiving unit is inconsistent with the moving body 8 away from the origin position. That is, since the positions of the signal source 13 and the light pipe 14 are shifted, no light passes through the light pipe 14 (see FIG. 5A (b)). Moreover, since the hole 7 of the rotating plate 6 is also shifted from the optical sensor 11, no light is detected by the optical sensor 11 (see FIG. 5A (a)).
And when the ball screw shaft 5 rotates with rotation of the motor 1 and the moving body 8 is approaching the rotating plate 6 along the guide rail 9, FIG. At this time, the hole 7 of the rotating plate 6 and the optical sensor 11 are in a position where they coincide (FIG. 5B (a)), and can be detected if light strikes. However, since the moving body 8 is away from the origin position, the positions of the signal source 13 and the light pipe 14 are shifted, so that no light passes through the light pipe 14 (FIG. 5B (b)). reference). In FIG. 5B (c), since the signal source 13 and the light pipe 14 do not form a signal path, the hole 7 of the rotating plate 6 cannot be irradiated with light.
Thus, the moving body 8 further moves along the guide rail 9, the positions of the signal source 13 and the light pipe 14 coincide with each other, the light from the signal source 13 is irradiated inside the light pipe 14, and the light from the signal source 13 A signal path to the pipe 14 is formed. Furthermore, when the hole 7 of the rotating plate 6 also coincides with the optical sensor 11 as shown in FIG. 5C (a), the light irradiated through the light pipe 14 reaches the optical sensor 11 through the hole 7. Thus, the light of the signal source 13 matches the signal path, the origin position P is detected by the optical sensor 11, and the origin position P can be confirmed (see FIG. 5C (b)).

  According to the above-described embodiment, the origin position is detected when the moving body approaches the detector installed in the fixed portion, and the position from the origin that can be detected and the position of the signal path provided on the rotary plate or the like match. By setting the origin, it is possible to detect the origin position with a single detector. Therefore, the origin position P can be detected with low cost and high accuracy.

  The present invention is not limited only to the above embodiment. For example, the detection target detects light with a photodetector and guides an optical signal to a light pipe to specify an origin detection range. A mirror such as a reflecting mirror can be used as long as it can guide the light. In addition, a rotating shaft driven by a motor is used for the linear motion mechanism for operating the moving body, but a belt mechanism can also be used. Needless to say you get.

DESCRIPTION OF SYMBOLS 1 Motor 2 Driver 3 Controller 4 Coupling 5 Ball screw shaft 5a Ball screw nut 6 Rotating plate 6a Plate surface 7 Hole (path through which light passes)
8 Moving object 9 Guide rail 10 Slide block 11 Optical sensor (photodetector)
12 Base plate 13 Signal source (light source)
14 Light pipe (optical transmission line)

Claims (3)

A rotating plate that shields light is rotated, and a moving body that is linearly operated along the axis of the rotating plate is provided.
Providing a path through which light passes through the surface of the rotating plate;
In the moving body, a transmission path for transmitting light toward the rotating plate is provided,
A light source that irradiates light toward the transmission path of the moving body is provided at a setting point in the middle of the moving path of the moving body,
A light detector that is disposed on the other side of the rotating plate opposite to the moving body and that detects light transmitted through the path through which the light transmitted by the transmission path passes,
An origin position detection method, wherein a position where a position where light is transmitted through the transmission path and a path where light passes through the rotating plate coincides is detected as an origin position of the moving body. A rotating plate operated to rotate,
The moving body that is operated in direct motion;
A path that is provided in the axial direction of the rotating plate and transmits light;
A transmission path provided on the mobile body for transmitting light;
A light source that is provided at a setting point in the middle of the moving path of the moving body, and irradiates light toward the transmission path of the moving body;
A light detector disposed on the other side of the rotating plate opposite to the moving body, and detecting light transmitted through a path through which light transmitted by the transmission path passes light;
An origin position comprising: the light detector for detecting, as an origin position of the moving body, a position where a position where light is transmitted through the transmission path and a path where light passes through the rotating plate coincides. Detection device.   The origin position detection device for a linear motion mechanism and a speed reduction mechanism according to claim 2, wherein a light pipe or a reflecting mirror is mounted on the moving body as a transmission path.

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