JPH0249214Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transport device for sequentially stopping and starting a moving body at one or more stations.

For example, when assembling work is performed sequentially at multiple stations on a product assembly transport line, high-speed transport of moving objects (pallets, trolleys, etc.) is required to minimize loss time, and when robot work is performed at the stations. requires high precision positioning.

Therefore, conventional conveyance devices of this type use induction linear motors as high-speed conveyance means.
This linear motor does not have accurate positioning ability. In particular, in a configuration in which the primary side is placed on the ground, there is no room for power supply to the movable side and the inertia is low, so it is often used for high acceleration/deceleration and high-speed conveyance, but when positioning after conveying a predetermined distance. In order to obtain high accuracy, forced positioning is performed by mechanical means such as a locate pin after sufficient deceleration. However, positioning using such locating pins requires mechanical equipment, and the durability and
There were problems with maintainability, etc.

On the other hand, there is a general method using a direct current motor and speed (rotation speed) feedback method, which is a purely electrical method.
Although the DC servo system has high precision and high performance, it has the drawback that the control system is quite complex and expensive, while the linear pulse motor system allows open loop control and high precision. However, due to the small overload capacity, it is easy to step out, making it unsuitable for applications requiring high-speed conveyance. For this reason, a system has been considered in which closed-loop control drive is performed using the position signal of the cart to prevent step-out, but linear A pulse motor cannot follow this.

The purpose of the present invention is to eliminate the conventional drawbacks in positioning by adding a linear pulse motor to a moving object conveying means based on an induction linear motor with its scale side fixed to the moving object. It is an object of the present invention to provide a high-speed, high-precision conveyance device based on non-contact drive that is durable and easy to maintain without causing impact.

The illustrated embodiment will be specifically described below. FIG. 1, FIG. 2, and FIG. 3 are a plan view, a perspective view showing the main parts, and an external view, respectively, showing the principle of the configuration in which the present invention is implemented. In each figure, reference numeral 1 denotes a free roller conveyor, which is laid in the direction of conveyance of a moving body (in this embodiment, a pallet), which will be described later. Stations 2a and 2b each perform their own work process. 3 is a pallet, which is guided by the free roller conveyor 1 and can move freely. 4a1 and 4b1 are moving magnetic field generating inductors of linear motors arranged in tandem in the transport direction with the center of the station 2a as a boundary. Numerals 4a2 and 4b2 are inductors for generating a moving magnetic field, and they are arranged equally with the inductors 4a1 and 4b1 for the station 2a and the station 2b adjacent to the station 2a. For these inductors 4a1, 4b1, 4a2, and 4b2, a conductor 4c shown in FIG. 4b1 etc. constitute a linear motor. 5a and 5b are magnetic flux generators forming the primary side of the linear pulse motor;
The pallet 3 is arranged at a position that can be positioned so that a desired location, for example, the center position, faces each of the stations 2a and 2b. That is, during the movement process of the pallet 3, a linear pulse motor scale 5c is placed on the bottom surface of the pallet 3 facing the magnetic flux generators 5a and 5b of the linear pulse motor.
is fixed, and the magnetic flux generators 5a or 5b and the scale 5c constitute a linear pulse motor to accurately position the pallet 3 to the stations 2a and 2b.

In the above configuration, the pallet 3 located to the left of the station 2a is loaded with conveyed objects (not shown) that are being sequentially manufactured into products in assembly line work and is conveyed at high speed in the direction of arrow A1 on the free roller conveyor 1. The robot advances to the station 2a. In this process, when the dielectric 4a1 reaches a state opposite to the conductor 4c arranged at the bottom of the pallet 3,
A deceleration effect is brought about with the generation of a moving magnetic field of the inductor 4a1 in the direction of arrow A2.

Next, when the scale 5c attached to the pallet reaches a specific position within the range where it faces the magnetic flux generator 5a and obtains the required drive, the moving magnetic field of the linear motor 4a1 disappears due to the action of a limit switch, etc., and the pallet 3 A linear pulse motor consisting of a linear pulse motor scale 5c fixed to a magnetic flux generator 5a is operated. At this time, the number of pulses corresponding to the amount of movement from the start of operation of the linear pulse motor consisting of the scale 5c and the magnetic flux generating device 5a to the desired stopping position of the pallet 3 is given to the magnetic flux generating device 5a. 3 is driven in principle in a step-like manner at a low speed in the transport direction A1, and the pallet 3 is positioned at the station 2a. The series of operations of the linear pulse motor described above are all automatically performed by known means such as operation commands of required steps and limit switches. The pallet 3 thus positioned with respect to the station 2a undergoes work such as assembly of objects to be transported placed thereon at the station 2a. Next, when the work at the station 2a is completed, based on a command from the operator, a moving magnetic field is generated for the linear motor inductor 4b1 in the direction of movement of the pallet 3 (direction of arrow A1), and the conductor in the pallet 3 is Based on the electromagnetic interaction with station 4c, the pallet 3 is transported toward the next station 2b. When the pallet 3 accelerated by the inductor 4b1 reaches a certain appropriate position, a position detecting means such as a limit switch is operated to stop the operation of the inductor 4b1 and at the same time operate the inductor 4a2. Accurate positioning of the pallet 3 to the station 2b, which is slowed down by a strong braking action by the inductor 4a2, is performed by the magnetic flux generator on the same principle as the operation at the station 2a. This is accomplished by driving a linear pulse motor consisting of scale 5b and scale 5c in the required steps. After the pallet 3 has been positioned at the station 2b, it performs the same operation as the station 2a. This station 2b
After the work is completed, the pallet 3 is inductor 4b2
The station is then sent to the next station (not shown). In the above operation, station 2
The relationship between the position and speed of the pallet 3 from a to the station 2b is shown in FIG. 4. That is, the pallet 3 is accelerated by the inductor 4b1 until it reaches a point X0 which is an appropriate distance from the station 2a, and from the point X near the station 2b.
1, deceleration control is performed based on the thrust of the inductor 4a2, and when a sufficiently low speed is reached, a limit switch is activated, and the magnetic speed generator 5b placed on the ground and the conductor 4c provided on the pallet 3 It is driven at a low constant speed by the required steps by a linear pulse motor, and is correctly positioned at the station 2b. The thrust-speed characteristic C1 of the linear motor provided by the inductors 4b1 and 4a2 during the transfer of the pallet 3 from the station 2a to the station 2b, and the magnetic flux generator 5b.
The relationship between the thrust-speed characteristic C2 of the linear pulse motor operating with the scale 5c and the load characteristic C3 of the pallet 3 is as shown in FIG.
The conveyance performance achieved by the high-speed response of the linear motor and the high-accuracy positioning characteristics of the linear pulse motor with its high thrust and low speed are clearly demonstrated.

Note that the above configuration in which the inductor and conductor constituting the linear motor are placed on the ground side and the pallet side, respectively, can also be arranged with the inductor placed on the pallet side and the conductor on the ground side. The acceleration linear motor can also be used in common with means for switching the direction of generation of the moving magnetic field. On the other hand, the arrangement of the magnetic flux generators 5a, 5b and the scale 5c can also be changed.

As described above, the conveying device according to the present invention skillfully utilizes each action of the linear motor and linear pulse motor when moving a positioning controlled moving object such as a pallet from one station to an adjacent station in the conveying direction. It is possible to utilize the features of each motor organically to achieve high-speed and highly accurate conveyance control. In other words, in moving body drive control using only linear motor action, noise is generated due to the requirement for a mechanical stopper.
Further, in the prior art in which positioning control is performed by mechanical coupling with a linear pulse motor during movement, there are problems with accuracy and durability due to repetition of the mechanical coupling. On the other hand, the shortcomings of moving object drive control using only linear pulse motors, such as the inability to perform high acceleration/deceleration and high-speed travel, have been improved, and the cycle time in which the moving object is transported while performing its own work at the station has been shortened. This frees up work time (product assembly, etc.), and since there is no room for using mechanical engagement, it not only eliminates noise during positioning, but also has excellent features such as easy maintenance. has.

[Brief explanation of the drawing]

Fig. 1 is a plan view, Fig. 2 is a perspective view of main parts, Fig. 3 is an external view showing the relationship between the pallet and its running path,
FIG. 4 is a graph showing the speed characteristics between each station of the moving body, and FIG. 5 is a graph showing the speed-torque relationship of the linear motor, linear pulse motor, and load. 1...Free roller conveyor, 2a, 2b...
Station, 3... Palette, 4a1, 4b
1, 4a2, 4b2...inductor for linear motor,
4c...Linear motor secondary conductor, 5a, 5b
...Magnetic flux generator for linear pulse motor, 5c...
...Scale for linear pulse motor.

Claims (1)

[Scope of utility model registration request] An inductor forming the primary side of the linear motor or a conductor forming the secondary side is provided at an appropriate position on a surface along the traveling direction of the moving body in a direction that applies at least one of a braking force and a driving force to the moving body, Each station is equipped with an electric conductor or inductor that constitutes a linear motor at a position opposite to the linear motor inductor or electric conductor provided on the moving body, and after the moving body enters a low speed region before positioning, One of the primary magnetic flux generator and the secondary scale, which constitute a linear pulse motor for positioning drive, is installed at an appropriate position on a surface along the moving direction of the moving body, and the other is placed on the traveling path of the moving body. A conveyance device characterized in that it is provided so as to face a primary side magnetic flux generator or a secondary side scale provided on a moving body.