JPH038625A - Transport device using linear motor - Google Patents

Abstract

PURPOSE:To prevent the collision of transported matters between themselves by maintaining a distance between both transported matters at more than a fixed value while these adjoining transported matters are being transported simultaneously or about at the same time. CONSTITUTION:In a case in which a transported matter P which is in the middle of being transported at a preset speed between the adjoining work stations on the basis of the operation control of a linear motor 23, has abnormally neared another transported matter which adjoins, due to some reason or other, this is detected by means of a position detection means. On the basis of this detection result, the transport speed of at least one of the adjoining transported matters P is corrected by means of a correction means 41, and the transported matter P is transported on the basis of the this corrected speed. As a result, in a case in which adjoining transported matters are transported simultaneously or the transport of a transported matter on the rear side of a transported direction is commenced when a transported matter on the front side is in the middle of being transported, the collision prevention of transported matters between themselves and the improvement of a transport efficiency are compatibly realized by changing suitably a speed in the middle of transport.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a conveyance device that conveys an object using a linear motor.

(Prior Art) Recently, in production lines of production factories, it has been desired to transport objects quickly and quietly in order to improve production efficiency and improve the working environment. As such a conveyance device, one using a linear motor including a linear motor coil and a reaction member is known. As shown in FIG. 8, for example, a conveyance device using this linear motor includes one of linear motor coils b, b, ... and reaction member c (linear motor coil b in the figure) that constitute linear motor a.
, b, ...) as a stator and a plurality of rollers d, d, ...) as a stator.
The linear motor coils b, b, . The thrust force F generated in the mover (reaction member C) by the electromagnetic action between ... and the reaction member C causes the pallet f and the objects placed thereon to be moved through the mover (reaction member C). configured to be transported.

In a control system of a conveyance device using this linear motor, as disclosed in, for example, Japanese Unexamined Patent Publication No. 56-141215, at least one of the position and speed of the pallet f during conveyance is usually detected, Based on the detection result, the linear motor a is operated (in detail, the linear motor coil b,
b, . . . ) is configured to control the amount of excitation of

(Issue 8 to be solved by the invention) By the way, when conveying objects sequentially to a plurality of work stations using a linear motor, adjacent objects may be conveyed at the same time, or objects on the front side in the conveyance direction may be conveyed simultaneously. If you start transporting the rear object during transport,
Since the distance between adjacent work stationers is short and the conveyance speed of the objects to be conveyed is extremely high, there is a risk that the objects to be conveyed will collide with each other.

On the other hand, in order to prevent such collisions between transported objects,
After the front object is transported and it is confirmed that the object is not present in the transport area of the rear object, the transport of the rear object can be started. be(
(See Japanese Patent Application Laid-Open No. 60-237803). However, in this case, the transport delay of the front side objects is accumulated in the transport of the rear side objects, so the time required for transporting the entire production line becomes considerably long, and the transport efficiency and production efficiency are reduced. The problem is that it's bad.

The present invention has been made in view of these points, and its purpose is to transport adjacent objects at the same time, or to transport objects on the rear side while transporting objects on the front side in the transport direction. Conveyance using a linear motor that can effectively prevent collisions between the conveyed objects and improve conveyance efficiency by appropriately changing the conveyance speed of the conveyed objects during transportation when starting the conveyance of The aim is to provide the equipment.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention as set forth in claim (1) provides a transport device that sequentially transports objects to a plurality of work stations using a linear motor. A control means for controlling the operation of a linear motor so that objects to be transported are transported between adjacent work stations at a preset speed, and a position detection means for detecting the current position of adjacent objects to be transported during transport. and, upon receiving a signal from the position detection means, correct the conveyance speed of at least one of the adjacent conveyed objects under the control of the control means so as to maintain the distance between the adjacent conveyed objects at a predetermined value or more. This configuration includes a correction means.

Here, the adjacent objects to be conveyed are controlled to be conveyed simultaneously after the work at the work station is completed as in claim (2), or during the conveyance of the conveyed object on the front side in the conveyance direction as in claim (3). Then, the conveyance of the rear object is controlled to start.

(Function) With the above configuration, in the present invention, when an object to be transported is transported between adjacent work stations at a preset speed based on the control of the control means that controls the operation of the linear motor, If, for some reason, an adjacent transported object comes abnormally close to another transported object, this is detected by the position detection means, and based on the detection result, the correction means adjusts the position of the adjacent transported object under the control of the control means. The transport speed of at least one of the objects is corrected, and the transported object is transported based on the corrected transport speed. As a result, the distance between adjacent objects to be transported is maintained at a certain value or more, and collisions between the objects to be transported are prevented.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 to 3 show a case in which a conveyance device A using a linear motor is applied to a vehicle assembly line as an embodiment of the present invention, and this conveyance device A carries pallets P as objects to be conveyed, The body B is conveyed between adjacent work stations within a certain period of time with the body B being aired on top of the body B.

The pallet P has a number of rollers 2, 2. ...
It is supported by a roller conveyor 3 consisting of a roller conveyor 3, and is conveyed while sliding on the roller conveyor 3.

Inside the support members 1, 1, a large number of linear motor coils 10.10. Two stator rows 11, 11 consisting of... are arranged in parallel. Each stator row 11 above
Two guide rails 12 extending in the transport direction are provided on both sides of the
．． 12 are arranged to guide a reaction member 14, which will be described later, along each of the stator rows 11.

In addition, guide rails 12.1 on both sides of each stator row 11 are provided.
2, a first plate 13 is movably engaged with and arranged on the lower surface of the first plate 13, and a reaction member 14 as a movable element made of, for example, laminated iron and aluminum in a plate shape is disposed on the lower surface of the first plate 13. It is integrally installed. Further, a second plate 15 extending upward is integrally attached to the upper surface of the first plate 13, and the second plate 15 extends upwardly.
A front and rear cylinder 16 having a piston rod 16a extending toward the front side in the conveyance direction (left side in FIG. 1) is arranged on the plate 15, and the piston rod 16a of the front and rear cylinder 16
A cylindrical member 17 is connected to the tip. The cylindrical member 17 is supported by the second plate 15 so as to be rotatable around a support shaft 18, and has an engagement projection member 19 provided on the back surface of the pallet P inside the cylindrical member 17. The proximal end of a rod 21 having an engaging block 20 at its tip is fitted and supported, and a coil spring 22 is attached to the rod 21.
is fitted externally. The reaction member 14 provided in each stator row 11 is moved along each stator row 11 by the thrust generated by the electromagnetic action between each stator row 11 and each linear motor coil 10. This causes the pallet P to be moved forward in the conveyance direction.
With the engagement block 20 engaged with the engagement projection member 19, the bodies B on the pallet P are sequentially conveyed between adjacent work stations within a certain period of time. Therefore, the linear motor coil 10 and the reaction member 14 constitute a linear motor 23, and one linear motor 23 is provided for each work station.

After the pallet P, which is the object to be transported, is transported to the front work station as described above, the rod 21 is rotated clockwise in FIG. As a result, the engaging state of the engaging block 20 with respect to the engaging projection member 19 is released and retracted diagonally downward, and in this state, the reaction member 14, which is moving forward to the front work station, is moved to the rear work station. It is designed to move backwards to the station.

Furthermore, vertical fluctuations occur when the pallet P moves over each roller 2 of the roller conveyor 3 due to the operation of the linear motor 23, but this fluctuation is absorbed by the coil spring 22 fitted onto the rod 21. This prevents the reaction member 14 from fluctuating in the vertical direction.

FIG. 4 shows a block configuration of a control section that controls the linear motor 23. In the figure, reference numeral 31 denotes speed detection means comprising an encoder for detecting the conveyance speed of each pallet P when the pallet P is conveyed between adjacent work stations;
Reference numeral 32 indicates a position detection means for detecting the current position of each pallet P when the pallet P is transported between adjacent work stations, and 33 indicates an operation thereof (in detail) provided corresponding to the linear motor 23 for each work station. 33 is a controller as a control means for controlling energization switching for each linear motor coil 10, and the controller 33 includes a controller 33 for controlling a pallet P between a corresponding work station and a work station on the front side in the transport direction (on the right side in the figure). A signal from a speed detection means 31 that detects the conveyance speed of the pallet P, and a position detection means 32 that detects the current position of the pallet P between the work station on the front side in the conveyance direction of the corresponding work station and the work station one further ahead in the conveyance direction. The signal from Specifically, as shown in FIG. 5, the position detecting means 32 includes three reflective tapes 34.34. It has three photosensors 36°36.36 provided in the
The conveyance start position (acceleration start position), constant speed conveyance transition position, and deceleration start position of the pallet P are detected at the positions where the light projected from the pallet 6 is reflected by the reflective tape 34, respectively.

Next, the operation control of the linear motor 23 and the conveyance control of the pallet P by the controller 33 will be explained using FIG. 6. Note that when the pallet P is transported between adjacent work stations, the first half of the transport is carried out by the controller 33 corresponding to the work station on the rear side in the transport direction.
In the latter half of the conveyance, the conveyance of the pallets P (operation of the linear motors 23) is controlled by the controllers 33 corresponding to the work stations on the front side in the conveyance direction, but for convenience, the control flow shown in FIG. 33.
- 33 shows the control for transporting the pallet P between adjacent work stations as a series of controls.

In FIG. 6, first, in step S1, the pallet located one front in the conveyance direction (hereinafter referred to as front or side pallet) P
is at the conveyance start position from the position detection means 32.
After a predetermined period of time has passed since the signal was received, the linear motor 2
3 is activated to start transporting the pallet P at a constant acceleration, and at the same time, the counter i is set to "0".

Next, in step S2, it is determined whether the Bl signal from the position detection means 32 indicating that the front pallet P is at the constant speed conveyance transition position is input within the reference time.

When this determination is YES, the conveyance speed of the pallet P is controlled based on the speed setting value set in advance in step S3. In this control, transportation is continued at a constant acceleration for a predetermined period of time when the Bll signal input is interrupted, and thereafter, transportation is performed at a constant speed.

Subsequently, after setting the counter j to "0" in step S4, in step S5 it is determined whether the C1 signal from the position detection means 32 indicating that the front pallet P is at the deceleration start position is input within the reference time. Determine. This judgment is YES
At this time, the conveyance speed of the pallet P is controlled based on the speed setting value set in advance in step S6. This control continues conveyance at a constant speed for a predetermined time after inputting the C1 signal, and thereafter conveys at a constant deceleration.

Then, when the pallet P is transported to a predetermined position of the work station on the front side in the transport direction and the transport speed becomes zero, the operation of the linear motor 23 is stopped in step S7. As described above, when the front pallet P is normally conveyed as specified, the conveyance control of the subsequent pallet P is completed. At this time, the mutual relationship between the transport speed of both the front and rear pallets P and each signal of the position detection means 33 is shown in FIG. 7A. As clearly seen from this figure, the transport speed v2 of the rear pallet P (lower part of the figure) changes with a predetermined time delay in phase with respect to the transport speed vl of the front pallet P (upper part of the figure).

On the other hand, when the determination in step S2 is NO, that is, the conveyance of the front pallet P is delayed, and the Bl from the position detection means 32 is
If the signal is not input within the reference time, the conveyance speed of the pallet P is reduced by 10% in step S8. Next, after counting up the counter l in step S9, it is determined in step S10 whether the counter i is 4 or more. If this determination is NO, step Sll
Determine whether or not the Bl signal is being input at the moment,
If the determination is YES, the conveyance speed of the pallet P is returned to the original speed in step S12, and then the process moves to step S3. On the other hand, if the determination in step S11 is No, the process returns to step S8. Also, the determination in step S10 is YE.
When S, that is, when the count i is 4 or more and the input of the 81 signal is delayed, it is assumed that an abnormality has occurred in the transport device, and the transport speed is reduced in step S13, and when the transport speed becomes zero, In step S14, the operation of the linear motor 23 is stopped. FIG. 7B shows the mutual relationship between the conveying speed of both the front and rear pallets P and each signal of the position detecting means 33 when the B1 signal is input with a delay.

Further, when the determination in step S5 is No, that is, the conveyance of the front pallet P is delayed, and the C1 from the position detection means 32 is
If the signal is not input within the reference time, the conveyance speed of the pallet P is reduced by 10% in step S15. Next, after counting up the counter j in step S16, it is determined in step S17 whether the counter j is 4 or more. If this determination is No, step S
In step S18, it is determined whether or not the CI multiplication signal is being input at the present time, and if the determination is YES, in step S19, a deceleration setting calculation is performed to stop the pallet P at a predetermined position of the work station on the front side in the transport direction. Step 20
Then, the conveyance speed of the pallet P is reduced by the deceleration obtained by the calculation.

Then, when the pallet P is transported to a predetermined position of the work station on the front side in the transport direction and the transport speed becomes zero, the operation of the linear motor 23 is stopped in step S21.

On the other hand, when the determination in step 318 is No, the process returns to step S15. Also, the determination in step S17 is Y.
In the case of ES, that is, when the count j is 4 or more and the input of the C1 signal is delayed considerably, it is assumed that an abnormality has occurred in the transport device, and the transport speed is decelerated in step S22, and when the transport speed becomes zero, In step 823, the operation of the linear motor 23 is stopped. FIG. 7C shows the mutual relationship between the transport speed of both the front and rear pallets P and each signal of the position detecting means 33 when the Ct multiplied signal is input with a delay.

As described above, a series of steps S2. S
8 to S14 and a series of steps S5 and 815 to S23, which also reduce the transport speed of the rear pallet P when the C1 signal is input with a delay, to keep the distance between the adjacent front and rear pallets P constant. A correction means 41 is configured to correct the conveyance speed of the rear pallet P so as to keep it above the value.

Therefore, in the above embodiment, the controller 33
Based on this control, the conveyance of the rear pallet P is started during the conveyance of the front pallet P in the conveyance direction, so the time required for conveyance throughout the production line is shortened, and the conveyance efficiency and production efficiency are improved. can be achieved. Also, both front and rear pallets P.

When conveying P at the same time, that is, the front and rear linear motors 2
Since a very large amount of power is not consumed each time as in the case where the activation times of 3 and 23 coincide, it is possible to save power consumption.

Furthermore, while the rear pallet P is being transported, the front pallet P
If a conveyance delay occurs for some reason and the Bl signal or Ct times signal from the position detecting means 32 for detecting the current position of the front pallet P is input to the controller 33 with a delay, the conveyance speed of the rear pallet P will be delayed. Since the speed is reduced from a preset speed and the distance between the front and rear pallets P is maintained at a certain value or more, collisions between the pallets P and P can be reliably prevented.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications.

For example, in the above embodiment, the present invention is applied to a case where the linear motor 23 is configured with the linear motor coil 10 as a stator and the reaction member 14 as a mover, but the present invention is not limited to this. The present invention can be similarly applied to the case where the linear motor 23 is constructed by disposing the reaction member 14 on the first plate 13 side to serve as a movable member, and by disposing the reaction member 14 along the conveyance line to serve as a stator.

In addition, in the above embodiment, adjacent objects (pallets) P
, P), when the front object is delayed in transport, the correction means 41 adjusts the speed of the rear object in order to keep the distance between the two waves above a certain value. Although the transport speed is configured to be slower than the preset speed, the transport speed of the front transported object may be configured to be increased faster than the preset speed, or the transport speed of the front and rear transported objects may be reduced. Of course, the conveying speed of each of the objects may be accelerated or decelerated.

Further, in the embodiment described above, the case where the conveying device A is applied to a vehicle assembly line is shown, but the present invention is not limited to this, and it goes without saying that the present invention can also be applied to the case of conveying other objects to be conveyed.

(Effects of the Invention) As described above, according to the conveying device using the linear motor of the present invention, while conveying adjacent objects simultaneously or one after the other, the distance between the two waves of objects is maintained at a constant value. Since it is possible to maintain the above value, it is possible to both improve the transport efficiency and prevent collisions between the transported objects.

[Brief explanation of drawings]

1 to 7 show embodiments of the present invention, in which FIG. 1 is a side view of the conveying device, FIG. 2 is a plan view thereof, and FIG. 3 is a cross section taken along the line ■-■ in FIG. 1. Figure 4 is a block configuration diagram of the control unit that controls the linear motor, Figure 5 is a schematic configuration diagram showing the configuration of the position detection means, Figure 6 is a flowchart diagram showing the control flow, and Figure 7 is the adjacent FIG. 6 is a diagram showing the mutual relationship between the conveyance speed of the pallet and each signal of the position detection means. Figure 8 shows a conventional example? ? This is a diagram equivalent to Figure i1. A... Conveyance device, P... Pallet (transferred object), 23... Linear motor, 32... Position detection means, 33... Controller (control means), 41... Correction means. Figure 3 Figure 7A Figure 70 Figure 7B Figure 8

Claims (3)

[Claims] (1) A conveyance device that sequentially transports objects to multiple work stations using linear motors, in which the linear motor is used to transport objects between adjacent work stations at a preset speed. a control means for controlling the operation; a position detection means for detecting the current positions of adjacent objects to be transported during transportation; A conveyance device using a linear motor, comprising: a correction means for correcting the conveyance speed of at least one of the adjacent conveyed objects under the control of the control means so as to maintain the conveyance speed of at least one of the adjacent conveyed objects. (2) Adjacent objects to be transported are controlled to be transported simultaneously after the work at the work station is completed (claim 1)
) Conveyance device using the linear motor described in . (3) Conveyance using the linear motor according to claim (1), wherein adjacent conveyed objects are controlled so that conveyance of the rear conveyed object is started during conveyance of the forward conveyed object in the conveyance direction. Device.