JPH01122303A - Positioning device for linear motor transporting apparatus - Google Patents

Abstract

PURPOSE:To enable a truck to be exactly positioned at a fixed position even if the speed and weight of the truck are changed, by setting a buffer which can be transferred to a position for stopping the truck and a position for getting rid of the truck when the truck passes. CONSTITUTION:When a truck 3 is applied for a linear motor for a stop station, then by a thrust in the counter direction of the linear motor, the truck 3 is decelerated. When it is detected that the truck is run at a low speed, then the linear motor is switched to a weak thrust in the positive direction. When the projection 4 of the truck 3 is struck against a buffer 13, then the truck 3 stops at the final end of the buffer 13 for balancing the weak thrust of the linear motor with the working force of the buffer 13. In this case, the buffer 13 of a station where the truck 3 is started or passed is switched toward a retreating position. As a result, the truck can be exactly stopped at high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a positioning device at a station of a conveying device using a linear induction motor.

O Prior Art FIG. 11 shows an example of the prior art, which includes a pair of pneumatically driven levers 1 and 2, and a protrusion 4 integrated with a trolley 3.
The stopper mechanism is configured to stop the cart 3, which has been slowed down by motor voltage control or the like, at a fixed position.

That is, when traveling from point P to point Q and stopping at point Q, when the trolley 3 reaches the first sensor 5 in front of the fixed position, the linear motor generates a reverse thrust to decelerate the trolley 3 to a low speed. ,
Furthermore, when the second sensor 6 immediately before the home position is activated, the cylinder 7
is actuated to raise levers 1 and 2, pinching the protrusion 4 of the trolley 3 and stopping it at the fixed position (if the trolley 3 is to be passed through without stopping at point Q, leave the levers 1 and 2 down).

O Disadvantages of the Prior Art In the above-mentioned prior art, when the stopper mechanism stops the cart at a fixed position, if the arrival speed changes due to load fluctuations, the impact becomes large. That is, referring to FIG. 12, the speed curve at the time of stopping is as follows:
It is accelerated by the rear lever 1, and further forward the second lever 2
When it hits the object, it is pushed back by inertia and once it passes the normal position, it returns to the normal position and stops. If the speed is too high, it collides with the second lever 2 in the front, and the energy is absorbed mainly by the compression of the air in the cylinder 7 and stops, but as the air expands, it is pushed back, and after repeating this reciprocating movement, it stops. In either case, there is a drawback that the impact is large, and since the cart stops after repeated reciprocating movements, it lacks smoothness, and it takes time for the cart to stop, which is an impediment to improving conveyance capacity.

OObject of the Invention In order to eliminate the above-mentioned drawbacks of the prior art, the present invention aims to eliminate the above-mentioned drawbacks of the prior art. It is an object of the present invention to provide a positioning device for a linear motor conveying device that can smoothly stop and position a fixed position without repeating back and forth movements.

OMeans for achieving the above object The present invention provides a shock absorber that can be changed to a position where it can be avoided when a bogie passes, and uses the weak thrust of the shock absorber and a linear motor. , bidirectional buffering and high-precision positioning and stopping.

EXAMPLE 0 The present invention will be described in detail below with reference to FIGS. 1 to 10.

A linear motor 11 is installed at each of stations I, II, and III, and a turntable 12 that can change direction is installed, and a buffer 13 is installed on the turntable 12.
By attaching the buffer and turning the turntable, the buffer 1
3 is freely movable to stop running to the right (position A), to stop running to the left (position B), and to a retracted position when passing (position C). In FIGS. 1 and 2, 14 is a rail.

Next, the dimensions of the protrusion 4 of the truck 3 are set as follows.

The length is twice the dimension β1 from the center of the turntable 12 when the shock absorber 13 is fully compressed, and the trolley 3 will stop at the center even if it is stopped from either the left or right direction.

The relationship between the width W and the dimension 12 from the center of the turntable 12 when the l1ilIi device 13 is fully extended is β,>W/2
The dimensions are such that the projection 4 and the stopper 15 do not interfere with each other in the retracted position.

Note that, referring to FIGS. 4 and 5, the turntable 12 is rotationally driven by a motor 16 and gears 17 and 18, and is configured to rotate as appropriate to positions A, B, and C. There is. Further, the turntable can also be rotated by a linear motor.

Next, the positioning operation according to the present invention will be explained.

We will explain the case of traveling from station ■ to ■ (passing I+).

Before starting at station I, change the direction of the buffer 13 (
Since the direction was the running direction in the previous cycle, this is converted to the retracted position. At this time, the linear motor 11
The shock absorber 13 is stopped, and as the shock absorber 13 changes direction, its restoring force (a force weaker than the running resistance of the trolley) restores it to the extended position.

On the other hand, on the restraining side steel section ■, the buffer 13 is moved to the seventh
Convert to the position shown in the figure (position A) and prepare for stopping.

When the operation is completed, the linear motor 11 of station I is driven to accelerate the trolley 3 (as shown in FIG. 3).

When the trolley 3 passes the linear motor 11, it enters a coasting state (from the opening to the bottom in FIG. 3). In this explanation, station (2) is passed through, so the buffer 13 of station II is at the position shown in FIG. 8 (position B).

When applied to the linear motor 11 of station (3), the speed is decelerated by the reverse thrust of the linear motor 11 (the position of the cart is detected by a sensor (not shown)) (C→2 in FIG. 3).

When the speed detecting device installed at each station detects that the speed has become low, the linear motor 11 is switched to a weak thrust in the forward direction, and the speed remains low until it hits the buffer 13 (2 → H in Figure 3). Run with

When the load changes, the speed curve from C → 2 → E and the low speed change, but when it hits the shock absorber, the energy of the truck 3 is absorbed (from Ho to Ho in Figure 3), and then the linear motor 11 After running for a short time at a slow speed that balances the weak thrust of the shock absorber 13, the operating force of the shock absorber 13, and the rolling resistance of the bogie 3, it stops at the end of the shock absorber 13.

This position is set in advance with high precision, and the trolley 3 is maintained at that position while being pushed by the weak thrust of the linear motor while working at the same station (toyuchi in FIG. 3).

When the next command is issued, it repeats the same action again and moves to the next station.

Since the operation is performed as explained above, the trolley 3 will not go too far, and furthermore, regarding smooth operation when stopped, the two extreme cases, that is, the speed when arriving at the shock absorber 13 is slow and the moving weight is light. We will explain when the residual energy is small and it stops immediately, and when the speed is fast and the moving weight is large.

Generally, the shock absorber 13 used for this exhibits the same repulsive force during the stroke, but in the device of the present invention, the shock absorber 1 has a characteristic that the repulsive force increases as it contracts, as shown in FIG.
3 gives good results. That is, FIG. 9(a) shows the case of arriving at an underspeed, (b) shows the case of arriving at an appropriate speed, and FIG. 9(C) shows the case of arriving at an excessive speed. It is within the capacity, and if it bounces, it will not come back and stop smoothly in the fixed position.

Effects of the Invention According to the present invention, even if a change in the weight of the cart (moving object) or an error in speed control occurs, the cart can be stopped at the station reliably and with high precision.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a positioning device for a linear motor conveyance device showing an embodiment of the present invention, and FIG. 2 is a side view of the same. FIG. 3 is an operation explanatory diagram showing the positioning operation of the present invention. 4 to 8 show the shock absorber and turntable, which are the main parts of the present invention. It is also a plan view, and Fig. 6 is a front view at the time of positioning and stop, and Fig. 7 is a plan view.
The figure is also a plan view, and FIG. 8 is a plan view with the buffer in position B. FIG. 9 is an explanatory diagram showing the effects of the present invention, and shows changes in the speed of the protrusion with respect to changes in the approach speed. FIG. 1O is a graph showing the characteristics of a preferred buffer. FIG. 11 is a schematic diagram showing a prior art positioning device. FIG. L2 is an explanatory diagram showing the operation corresponding to FIG. 10. 3...Carriage 4...Protrusion 11...Positioning device 12...Turntable 13...Buffer Fig. 10 Stroke Fig. 4 Figure 5

Claims (1)

[Claims] In a device that controls the direction and strength of the thrust of a linear motor to obtain high and low speeds to drive a bogie, a shock absorber that can be changed to a position where the bogie is stopped in the forward and reverse directions, and a position where the bogie can be avoided when passing. 1. A positioning device for a linear motor conveyance device, characterized in that it is equipped with a shock absorber and uses the weak thrust of the linear motor to perform bidirectional buffering and high-precision positioning and stopping.