JPH0522445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conveyance device used in a factory or the like, and particularly to a position detection device that detects the position of a moving object at a predetermined stop position on a conveyance path.

BACKGROUND ART Conventionally, as a means for transporting objects in a product assembly transport line, etc., a LIM type transport device using a single-sided linear induction motor (hereinafter abbreviated as LIM) as a power source has been known. This LIM type conveyance device has multiple LIM stators (hereinafter referred to as stators) arranged at predetermined intervals along the conveyance path.
, a movable body having a secondary conductor (hereinafter referred to as a reaction plate) as a movable element of the LIM attached to the lower surface; The movable body is moved to a predetermined position by appropriately controlling the excitation of the stator, and is thereby placed on the movable body. It is designed to transport objects.

By the way, in this type of LIM type conveyance device, the moving object can be moved at a relatively wide range of speeds (0.1 to 5 m/
sec) to move in a straight line. As a method for positioning and stopping this moving body at a predetermined stop position on the conveyance path, a position detection device that detects the position of the movable body is provided at a predetermined stop position, and the LIM is detected based on the detection signal of this position detection device. A method has been adopted in which the excitation of the stator is controlled and the movable body is thereby positioned and stopped. FIG. 1 is a diagram showing an example of the configuration of a LIM type conveyance device equipped with such a position detection device. Note that this figure shows a cross section when the conveyance device is cut along the width direction of the conveyance path at a predetermined stop position of the moving body. In this figure, reference numeral 1 denotes a rail having a concave cross-section, and is fixed to the floor surface with its protrusion facing upward. As a result, a straight conveyance path is formed in a direction perpendicular to the plane of the paper. A stator 2 is attached to the top surface of the bottom of the rail 1. A plurality of stators 2 are arranged at predetermined intervals along the conveyance path. 3 is a moving body, and rollers 4a, which are attached to this moving body 3,
4b, side rollers 5a, 5b, and cam followers 6a, 6b. In this case, the movable body 3 is movable along the conveyance path, with displacement in the width direction and vertical direction of the conveyance path being almost completely restricted. Reference numeral 7 denotes a reaction plate attached to the lower surface of the moving body 3, and is arranged to face the stator 2 vertically. 8 is a position detection device;
As shown in the figure, it is composed of a slit plate 9 and a transmission type photo sensor (hereinafter simply referred to as a photo sensor) 10. This slit plate 9 has a plurality of slits 9a, 9a, . . . formed at equal intervals along its longitudinal direction. (See Figure 1). Also,
The photo sensor 10 is disposed at a predetermined stopping position of the movable body 3 on the conveyance path, and is placed on the inner surface of the rail 1 so that the slit plate 9 passes through the gap G between the light emitter 10a and the light receiver 10b. is attached to. When the movable body 3 moving on the rail 1 approaches a predetermined stop position, the slit plate 9 attached to the lower surface of the movable body 3 passes through the gap G of the photo sensor 10, thereby detecting the position of the movable body 3. be done. Next, the movable body 3 is positioned and stopped by appropriately controlling the excitation of the stator 2 based on the position detection result.

Now, in the conventional positioning device 8 described above, the gap G is set to 2 in order to detect the position with high accuracy.
A photo sensor 10 of about 3 mm is used. As a result, the slit plate 9 is attached to the photo sensor 10.
In order to prevent contact with the light emitting part 10a or the light receiving part 10b, displacement in the direction perpendicular to the moving direction of the moving body 3, in other words, lateral vibration of the moving body 3 must be almost completely prevented with high precision. It won't happen. Therefore, it is necessary to provide the movable body 3 with a lateral vibration prevention mechanism such as side rollers 5a, 5b, etc., which has the drawback of complicating the structure of the entire conveying device.

In view of the above-mentioned circumstances, the present invention eliminates the need to provide a lateral vibration prevention mechanism for preventing lateral vibration of a moving body with high precision, and even when the lateral vibration of a mobile body occurs within a predetermined range, the mobile body It provides a position detection device that can detect the position of
A position detection device for detecting the position of a movable body moving along a conveyance path includes: a slit plate attached to the movable body and having a large number of slits formed along the traveling direction of the movable body; It consists of a light projecting part and a light receiving part which are arranged at a predetermined interval in a direction transverse to the traveling direction of the moving body, and when the slit plate passes through the space between the light projecting part and the light receiving part, the movement of the moving body is A photo sensor that outputs a detection signal for detecting a position from the light receiving section, and a photo sensor that faces the light projecting section and the light receiving section on the entry and exit sides of the slit plate so as to sandwich the slit plate therebetween. The attached guide members each have a gap gradually extending from the entrance side or the exit side of the slit plate to between the light emitting part and the light receiving part in order to smoothly guide the slit plate to the photo sensor. a guide member formed to have a narrow width; a slider mounted with the photo sensor and the guide member; and a slider mounted on the conveyance path, the slider being movable in a direction transverse to the traveling direction of the movable body. and a plate spring that is inserted between the slide base and the slider and biases the slider so that the slider is always located at the center of the slide base. It is said that

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram showing the configuration of a LIM type conveyance device equipped with a position detection device according to an embodiment of the present invention, and similarly to FIG. A cross section cut along the width direction of the conveyance path is shown. Further, in this figure, parts corresponding to those in FIG. 1 are given the same reference numerals. In this figure, reference numeral 19 denotes a long plate-shaped base arranged along the conveyance path and fixed to the floor surface. This base 19
Frames 20a and 20b each having a U-shaped cross section are vertically fixed to both ends of the frame in the width direction by bolts 21a and 21b, respectively. These frames 20a
and rollers 22a and 2 at the upper end of 20b.
2b is rotatably mounted on shafts 23a and 23b, and side rollers 24a and 24b are rotatably mounted on shafts 25a and 25b. In this case, the roller 22
a and 22b are each arranged toward the inside of the conveyance path, and rollers 24a and 24b are each arranged toward the upper side. In addition, on the top surface of the base 19
LIM stator 2 is attached. A conveyance path is formed by the above configuration. Note that a plurality of stators 2 and frames 20a, 20b are each arranged at predetermined intervals along the conveyance path. On the other hand, a flat moving body 26 is placed on the rollers 22a and 22b. This movable body 26 has rollers 22a and 22b on the lower surfaces of both ends in the width direction.
The movement in the width direction is restricted within a predetermined range by side rollers 24a and 24b. Further, a reaction plate 7 and a slit plate 9 are respectively attached to the lower surface of the movable body 26. In this case, the reaction plate 7 is disposed at a position vertically facing the stator 2, as in the conventional case, and the slit plate 9 is also arranged with its longitudinal direction aligned with the moving direction of the moving body 26, as in the conventional case. installed. Furthermore, an L-shaped support member 30 is attached by bolts 31 to the inner surface of the pedestal 21a at a predetermined stop position of the movable body 26. A sensor device 32 shown in FIGS. 4A and 4B is attached to the upper surface of the horizontal portion of the support member 30 by bolts 33, 33, . . . . In Figure 4 A and B, 34
is a slide base composed of a square plate body, and a groove 34a is formed on the upper surface of the slide base in a direction that corresponds to the width direction of the conveyance path (direction of arrow Y shown in the figure). Convex portions 34b and 34c that are parallel to each other are formed sandwiching 34a. A permanent magnet 35 is attached to the center of this groove 34a. In addition, the slide base 34
A slider 37 made of a rectangular plate is placed on the upper surface of the slider 37 with four steel balls 36, 36, . . . interposed therebetween. At the center of the lower surface of the slider 37, there is a convex portion 37a extending in a direction coinciding with the width direction of the conveyance path.
is formed, and convex portions 37b and 37c are formed in parallel to the convex portion 37a at both ends of the lower surface in the transport direction (direction of arrow X shown in the figure). The slider 37 has convex portions 37b and 37c formed on its lower surface and the slide base 3.
The steel balls 36, 36, . Convex portion 37a formed on the lower surface
is attracted by a permanent magnet 35 attached to the slide base 34, thereby preventing upward movement. Further, the center portions of substantially V-shaped leaf springs 38 are attached to the center portions of the side surfaces of both ends of the slider 37 in a direction that coincides with the width direction of the conveyance path, respectively, by screws 39, 39. . The tips of the leaf springs 38, 38 abut the heads of the bolts 33, 33, . . . at the four corners of the slide base 34, thereby holding the slider 37 at the center of the slide base 34. Further, a photo sensor 10 is attached to the center of the upper surface of the slider 37 with screws 40, 40. In this case, the photo sensor 10 is arranged with its light projecting section 10a, gap G, and light receiving section 10b sequentially aligned with the width direction of the conveyance path. Also, the slider 37
Guide members 41a to 41d are respectively attached to the four corners of the upper surface by screws 42, 42, . . . . These guide members 41a and 41b form a guide groove 43a that guides the front edge of the slit plate 9 to the gap G of the photo sensor 10, and
A similar guide groove 43b is formed by the guide members 41c and 41d. These guide members 4
1a to 41d are made of synthetic resin so as not to damage the slit plate 9. In addition, the guide groove 4
3a is formed to be larger than the gap G of the photo sensor 10 at the entrance where the slit plate 9 enters (gap G ₁ ), and is formed so that the gap gradually narrows as it approaches the photo sensor 10. Further, the guide groove 43a is slightly smaller than the gap G between the photo sensor 10 near the photo sensor 10 (gap G ₂ ), and the gap widens as it approaches the photo sensor 10.
0, the gap is formed to be the same as the gap G of the photo sensor. Further, the guide groove 43b is also formed in the same manner as the guide groove 43a. The above-described sensor device 32 and slit plate 9 constitute a position detection device 45.

Next, the operation of detecting the position of the moving body 26 by the above-mentioned position detection device 45 will be explained with reference to FIG. 3 and FIGS. 4A and 4B. First, in FIG. 3, the side rollers 24a and 24b correct the lateral vibration of the movable body 26, which has moved toward the front in the drawing, to within a predetermined range. here,
The predetermined range is the gap at the entrance of the guide groove 43a formed by the guide members 41a and 41b.
It is the same value as G ₁ . (See FIG. 4A) Next, the moving object 26 approaches the sensor device 32, and the moving object 26 approaches the sensor device 32.
The front edge of the slit plate 9 attached to the lower surface of the sensor device 32 reaches the guide groove 43a of the sensor device 32. Next, the front edge of the slit plate 9 is guided by the guide groove 43a, reaches the gap G of the photo sensor 10, and is further guided by the guide groove 43b, passing through the sensor device 32. At this time, for example, if the slit plate 9 is displaced in the direction of the arrow Y shown in FIG. As a result, the slider 37 moves in the direction of arrow Y against the biasing force of the plate springs 38, 38. As a result, the slit plate 9 always passes through the gap G of the photo sensor 10. Further, after the slit plate 9 passes the sensor device 32, the slider 37 returns to its initial position, that is, to the center of the upper surface of the slide base 34.

As explained above, according to the present invention, in a position detection device that detects the position of a moving body moving along a conveyance path, a large number of slits are attached to the moving body and arranged along the traveling direction of the moving body. A light emitting part and a light receiving part are arranged at a predetermined distance apart from each other in a direction transverse to the traveling direction of the moving body, and the distance between the light emitting part and the light receiving part is defined by the above. a photo sensor that outputs a detection signal for detecting the position of the moving object when the slit plate passes from the light receiving unit; and a photo sensor that outputs a detection signal from the light receiving unit to detect the position of the moving object when the slit plate passes therethrough; Guide members are mounted oppositely to each other so as to sandwich the slit plate, and each guide member extends from the entrance side or the exit side of the slit plate to between the light emitting part and the light receiving part. a guide member formed so as to gradually narrow the gap to guide the photo sensor smoothly; a slider on which the photo sensor and the guide member are mounted; a slider attached to the conveyance path; a slide base that supports the movable body so as to be movable in a direction transverse to the direction in which the movable body moves; Since a biasing plate spring is provided, the position of the moving body can be detected even if the moving body lateral shakes within a predetermined range, and therefore, the position of the moving body can be detected to prevent lateral shake of the moving body. The lateral vibration prevention mechanism, such as the side rollers, is simplified, which provides an advantage in that the configuration of the entire conveying device is simplified.

[Brief explanation of the drawing]

Figure 1 shows a conventional position detection device installed.
FIG. 2 is a cross-sectional view showing an example of the configuration of a LIM type conveyance device, FIG. 2 is a perspective view showing the configuration of the conventional position detection device shown in FIG. 1, and FIG. 3 is a position detection device according to an embodiment of the present invention. FIGS. 4A and 4B are a plan view and a front view showing the structure of the position detection device shown in FIG. 3. FIGS. 9... Slit plate (detected element), 10... Transmissive photo sensor (detection means), 34... Slide base, 35... Permanent magnet, 36... Steel ball, 3
7... Slider, 38... Leaf spring, 41a-41
d...Guiding member.

Claims (1)

[Claims] 1. A position detection device for detecting the position of a moving body moving along a conveyance path, which is attached to the moving body and has a large number of slits formed along the traveling direction of the moving body. It consists of a slit plate, and a light projecting part and a light receiving part that are arranged at a predetermined distance apart from each other in a direction transverse to the traveling direction of the moving body, and the slit board passes between the light projecting part and the light receiving part. A photo sensor that outputs a detection signal for detecting the position of the moving object from the light receiving section; and a slit plate on the side where the slit plate enters and the side where the slit plate leaves the light projecting section and the light receiving section, respectively. guide members installed opposite to each other so as to sandwich the slit plate from the entrance or exit side of the slit plate to between the light emitting part and the light receiving part, respectively, to smoothly guide the slit plate to the photo sensor. a guide member formed to gradually narrow the gap for guiding; a slider mounted with the photo sensor and the guide member;
a slide base that supports the movable body so as to be movable in a direction transverse to the traveling direction of the movable body; and a slide base that is inserted between the slide base and the slider, and that is attached to the slider so that the slider is always located at the center of the slide base. 1. A position detection device for a movable body in a conveyance device, comprising a biasing plate spring.