JPH03102007A - Positioning device for linear transport dolly - Google Patents

Abstract

PURPOSE:To realize the correct and speedy positioning in noncontact form by installing a linear induction motor primary side in a station part and installing a positioning electromagnet at a regular stop position and an approach sensor on the both sides of the positioning electromagnet and installing a reaction plate and an iron piece for magnetization on the dolly side. CONSTITUTION:When a dolly 4 advances in the direction of arrow, a sensor 2A operates to energize the linear induction motor primary side 3 in the direction for brake-applying the dolly 4. At the same time, also a positioning electromagnet 8 is energized. While, the speed of the dolly 4 is detected by the detection signals of the sensors 2A-2C, and it is judged if the speed of the dolly 4 is the speed at which the dolly 4 is stopped at a regular position by the attractive force of the positioning electromagnet 8. When stop is enabled, the excitation of the linear induction motor primary side 3 is cut off, and the dolly 4 is advanced with inertia. When an iron piece 10 passes through the electromagnet 8, the dolly 4 is stopped by the attractive force. The stop position is corrected by the shift in the second time if necessary. Thus, the speedy and correct stop is realized in noncontact form.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention enables a linear transport vehicle driven by a linear motor to stop accurately and quickly at a stop position.

[Conventional technology]

A method for stopping a trolley in a fixed position using a linear conveyance device using linear induction motors ■ The thrusts of the two linear induction motors in the stop station are made to face each other, and the trolley is stopped at a point where the thrusts received by the trolley are balanced. let

■ When the truck goes too far past the stopping point, the linear induction motor generates thrust in the opposite direction to the direction of travel, causing it to go back.

■ There are methods such as running the trolley at low speed within the station, capturing the trolley with a mechanical stopper at the stop position, and mechanically locking it.

[Problem to be solved by the invention]

The conventionally adopted methods in items ■ and ■ are non-contact stopping methods, but it is difficult to control the thrust of the motor to stop the cart, and moreover, the cart repeatedly moves back and forth around the stop position before stopping. The disadvantage is that it takes a long time to stop because it stops while the machine is moving.

In addition, since the method described in section (■) is a contact type, it can be reliably stopped in a fixed position, but since the stopper is forced to stop mechanically with the moving cart, the stopper absorbs a large amount of energy when stopping on large transport carts. It cannot be done and will be destroyed immediately. Additionally, there are drawbacks such as noise being generated when the cart is captured.

An object of the present invention is to quickly and accurately position a cart without electrical contact.

[Means to solve the problem]

The present invention has been made to achieve the above object, and has one of the primary side and the secondary side of a linear motor installed at a trolley stop station on the conveyance path side, and the other at the trolley side, and which stops the trolley at a predetermined position. In order to hold the position, either a magnetic pole around which the coil of the holding electromagnet is wound or a positioning iron piece that receives an attractive force in opposition to the magnetic pole is installed on the conveyance path side of the stop position, and the other side is installed on the cart side. In addition, when the cart comes to the station, the linear motor decelerates the cart, and the holding electromagnet's attraction force stops and holds the cart at a predetermined position. A stop position detection sensor and re-movement speed of the dolly that detects the location when the dolly stops short of the stop position or stops too far and controls the re-movement speed of the dolly according to the distance to the predetermined stop position. A control device is provided to accurately and quickly stop the truck at a fixed position.

[For production]

A holding electromagnet captures a trolley running at low speed,
In order to stop the cart at a fixed position, the speed after the cart enters the stopping station and is decelerated should be equal to or less than the speed commensurate with the cart capturing force of the electromagnet. However, the speed of the cart after deceleration varies depending on the weight of the transport path, the resistance between the cart and the transport path, the deceleration force of the linear motor, etc., so the cart is not always at the appropriate speed at the holding electromagnet. . Also, the vehicle may stop before the stop position, or may stop after going too far. In such a case, if the cart is moved to the electromagnet again at a proper speed, it will stop correctly.

However, if the initial stopping place is far from the regular stopping position, it will take time to move it again at the proper acquisition speed, so move quickly at first and then return to the stopping place so that it reaches the proper speed as it approaches the electromagnet. Since the re-movement speed is controlled accordingly, the trolley can be accurately stopped at a fixed position.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

In the figure, reference numeral 1 denotes a conveyance path along which a trolley is moved by a linear induction motor.The conveyance path 1 is arranged along the route for conveying the trolley to other predetermined locations within the factory. .2 is provided.

In the transport path 1, the linear induction motor primary side 3 is disposed at an appropriate position and is also provided at the stop position of the trolley 4, and the trolley 4 running on the rails 2 of the transport path 1 has running wheels 5.
A secondary side reaction plate 6 is provided which receives thrust on the primary side 3 of the linear induction motor.

Further, a stop station S is set at a predetermined position on the conveyance path l, and a mounting plate 7 is provided protrudingly at or near the center of this fixed position, for example, the stop station S, and a positioning electromagnet 8 is attached to this mounting plate 7. In addition, a plurality of proximity sensors IA, IB, IC and 2A, 2B, 2 are located within the stop station S at regular or arbitrary intervals in the front and back of the transport direction around the electromagnet 8.
Arrange C.

An electromagnet iron piece 10 is provided on the side surface of the truck 4 either directly or via the sensor mounting plate 9, so that the electromagnet iron piece 10 and the positioning electromagnet 8 face each other when the truck 4 stops at a fixed position.

Next, the operation and effect of the present invention will be explained. Trolley 4
When the bogie enters in the direction of the arrow in FIG. 1, the sensor 2A detects its progress and the linear induction motor is energized so as to brake the bogie. At the same time, the positioning electromagnet is also excited. On the other hand, the speed of the cart is detected, and if the speed is such that it can be stopped at the correct position by the attractive force of the positioning electromagnet, the excitation of the primary side of the linear induction motor is cut off, and the cart coasts. As a method of speed detection, there is a method of calculating the speed using a speed calculator built in the traveling control device shown in FIG. 4 from the time difference when two sets of adjacent sensors sequentially detect the bogie and the distance between the sensors.

When the iron piece for the electromagnet provided on the cart passes the teeth of the positioning electromagnet shown in FIG. 2 while the cart is coasting, the iron piece of the cart tends to be attracted by the attractive force of the electromagnet. The attractive force at this time acts as a braking force to stop the cart, and the position of the cart is maintained by the attractive force acting between the electromagnet and the iron piece. Therefore, the cart can continue to stop without contacting the electromagnet. However, in reality, due to changes in the friction coefficient between the wheels and rails due to the size of the load on the bogie and the dirt on the rail surface during use, the bogie may come to a spontaneous stop before the normal stop position during coasting. In other cases, the vehicle may not decelerate to a predetermined speed with a predetermined deceleration force and may come to a natural stop after passing through a normal stop position. In such a case, the trolley is moved again to the normal stop position using the linear induction motor. The re-movement speed at this time is set to be a speed that is sufficiently slow so that the cart can be stopped by the attractive force of the positioning electromagnet. However, if you move again at a slow speed from the beginning, it will take time to stop at the normal position, so sensors IA to IC detect the natural stop position. For example, when the natural stop occurs far away from the normal position, The motor thrust is increased during re-movement to move the cart again at high speed, and as the cart approaches the normal stop position, the thrust is reduced to reduce the speed. FIG. 3 shows the motor thrust characteristics when the truck moves again from the natural stop position and the motor thrust is reduced according to the distance to the normal stop position to bring the truck to a predetermined low speed.

FIG. 3 shows that the degree of change in thrust varies depending on which of the sensors IA to IC detects the bogie stop position. For example, do this at 1C when the trolley is close to its normal position.
When it comes to a natural stop at the sensor, the I
This is because the thrust for moving again is not needed as much as when stopped by sensor A.

FIG. 4 shows the control block. To explain the operation with reference to the figure, sensor A detects that the cart has entered the station, and the positioning electromagnet for normal positioning is energized in accordance with instructions from the cart controller that receives the signal output.

As the truck enters, the speed is calculated by the speed calculator of the re-movement speed control device using the sensors 2A to 2C, and according to the results, a deceleration force instruction is sent to the inverter from the truck controller.The output of the inverter is controlled.

Using the output of the inverter, a deceleration force suitable for the approach speed is output from the primary side of the linear motor, and the bogie is decelerated. Next, when the speed of the truck is reduced to a predetermined value or less, the near motor excitation is turned off in response to an instruction from the truck controller, and the truck moves forward. When the iron piece for the electromagnet of the cart is captured by the attraction force of the positioning electromagnet in this coasting width, the cart will stop at the normal position, but if it passes through the normal position, it will come to a natural stop at a certain position. For example, if the position is at the sensor IA, the stop position determiner informs the re-movement controller of the stop position according to the sensor output of IA, and the controller instructs the output of the inverter according to the information. The inverter causes the linear motor to generate re-moving thrust according to the instructions.

Furthermore, since the inverter controls the thrust according to the characteristics shown in FIG. 3, the cart does not go too far after moving again and stops at the normal stop position due to the attraction force of the electromagnet.

In addition, in the above embodiment, a rail track was used for the conveyance path, but a floating traveling type can also be applied, and the linear motor is not limited to an induction motor, and other motors can also be used. Furthermore, it is also possible to provide the primary side of the motor on the moving side.

〔Effect of the invention〕

According to the present invention, the cart can be easily stopped in a mechanical non-contact manner by combining the cart detection sensor and the controller that controls the motor thrust, and the stopping position can be accurately determined, and the structure is more convenient than the mechanical stopping and holding method. Since it is simple and has no moving parts, it has advantages such as improved reliability of operation.

[Brief explanation of drawings]

Fig. 1 is an external perspective view of the main parts, Fig. 2 is a plan view, Fig. 3 is a graph, Fig. 4 is a block diagram of the operation of the present invention, Fig. 5
The figure is a flowchart. 1 is a transport path, 2 is a rail, 3 is a linear induction motor primary side, 4 is a trolley, 6 is a reaction plate, 8 is a positioning electromagnet, IO is an iron piece for the electromagnet, S is a stop station, IA, IB, IC. 2A, 2B,
2C is a sensor. (1 other person)

Claims (1)

[Claims] (1) A linear induction motor primary side is installed in the station section of the conveyance path, and positioning electromagnets are installed at locations corresponding to the normal stop position of the cart, and on both sides of the magnet, when the cart enters the station and stops, In order to detect the position, a plurality of proximity sensors are provided to cover the range of the stop position, and the trolley is provided with an iron piece for electromagnets corresponding to the linear motor secondary reaction plate and the regular positioning electromagnet. A positioning device for a linear transport vehicle, which is characterized by: