JPH0548067B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conveyance device using a linear step motor used in a processing assembly line or the like, and particularly to a conveyance device having an XY positioning function within a processing assembly station.

Devices that use linear step motors for conveyance can only move in one direction, like conveyor conveyance. The whole thing is always sent at a constant speed. Even with intermittent feeding, it is difficult to stop and locate the transported object. In addition, it is impossible to position the transported object unlike transport using a linear induction motor. There is also no drawback that it is difficult to control the deceleration and stop of the conveyed object.

The inventor of the present invention focused on these characteristics of the linear step motor, arranged windings only in the station section on the track side, provided a secondary section on the conveyed cart, and realized that the linear step motor can perform processing.・We have developed a transport device that precisely positions the cart at the assembly station, and uses inertia from acceleration at the station to move between stations. (Japanese Patent Application No. 56-104035) The present invention further improves the above-mentioned invention and aims to provide a conveying device that can also position and convey a truck in a direction perpendicular to the direction of travel of the truck.

A detailed explanation will be given below with reference to the drawings.

In the previously disclosed conveyance device, workpieces or semi-assembled products are fixed or placed on pallet trucks and are moved on guide tracks disposed across the processing and assembly line.

In a station where processing and assembly work is performed, as shown in FIG. 1, an appropriate number, for example, eight linear step motor windings 3 are arranged between tracks 2 having lateral guides 1. . This winding part 3 consists of a magnetic core 5 having a winding 4 in the center and is arranged at right angles to the track 2.

The pallet truck 6 runs on the track 2 with a car 7, and on its lower surface, grooves 8 of equal pitch are provided at a position facing the magnetic core 5 and serve as the secondary side of the linear step motor. 9 is a lateral guide wheel.

Normally, in linear step motors, the winding side moves, but in this device,
Conversely, by fixing the windings to the track side, there is no need to supply power to the bogie, allowing the bogie to move over long distances.

The handling of the bogie becomes easier, such as the ability to freely remove the bogie from the track.

You can freely increase or decrease the number of carts running on the line.

In a processing assembly line, the intervals between stations are not very large, so if the stations are moved by inertia, the windings only need to be placed on the stations, so the equipment cost will not be that high and the number of carts handled will be reduced. The more the value increases, the more advantageous it becomes.

It has the following advantages.

Furthermore, as is well known, in a linear step motor, the carriage moves by sequentially switching the excited windings. If this switching of the excitation phase is performed according to a predetermined program using so-called open-loop drive using on/off commands from an external oscillator or computer, the positioning of the cart within the station can be performed by numerical control. Since this process is easy, the cart can be used like a processing/assembly table. The positioning accuracy in this case is determined by the structure of the linear step motor, particularly the pitch of the grooves 8 and the number of phases of the windings. In the simplest case, the carriage rests at a position where one tooth of the groove 8 faces the excited magnetic core 5, so the resting position of the cart will be at discrete positions depending on the pitch between the magnetic core 5 and the groove 8. By adjusting the balance of the excitation currents of the adjacent magnetic cores 5 accordingly and exciting them simultaneously, it becomes possible to position the magnetic cores 5 at any position between the adjacent magnetic cores 5.

By energizing the magnetic core in this manner, it is possible to obtain a force for holding the cart at the set position at the same time as positioning. When some strong external force such as processing force is applied, the position of the cart can be detected and used as a feedback signal to prevent the cart from shifting.

FIG. 2 has almost the same structure as FIG. 1, and instead of providing a cart 6 with a wheel 7, the pallet 10 has only a groove 8, and the pallet is moved by rollers 11 distributed in the passage. This is an example. The lateral guidance is also not by the guide wheel 9 but by the guide rollers 12 that abut against the side surfaces of the pallet. Other parts having the same structure as in FIG. 1 are given the same reference numerals. Such a device operates in exactly the same manner as the example shown in FIG. 1, and can be controlled in the same manner. In the present invention, the term pallet truck is not limited to this, and is used in a sense that includes many variations.

The pallet truck controlled by the linear step motor as described above moves in the direction of its movement (arrow A
However, in the direction perpendicular to this direction (direction of arrow B), the winding portion 3 has almost no position-holding force.

Therefore, in order to guide the pallet truck within the station in the lateral direction shown by arrow B, position it accurately, and hold it, a bearing or the like is generally installed between the reference surface of the station and the side surface of the pallet truck. A method has been adopted in which the pallet truck is guided in the lateral direction via the pallet truck. In order to maintain the position against external forces, a method is used in which one side of the pallet truck is pressed against the reference surface of the station by some method after it comes to rest. However, such a lateral guiding and holding method has disadvantages such as a complicated structure of the station and energy loss when accelerating the cart or pallet within the station.

The pallet truck of the present invention maintains the above-mentioned advantages while also obtaining lateral guidance and position holding force within the station by the electromagnetic force of the driving electromagnet. For this purpose, grooves 8' and the magnetic core 5' of the winding section 3, which serve as the secondary side of the linear step motor, are provided with grooves cut parallel to the traveling direction, as shown in FIG.

By doing this, based on the principle that the magnetic flux from each electromagnet forms a magnetic path with as little magnetic resistance as possible, if the pallet truck tries to shift laterally within the station, the groove 8' A restoring force acts so that the convex portions of the magnetic core 5' face directly. As a result, the translational shift of the pallet truck and the restoring force at the fixed position can be obtained in a non-contact manner without adding a special guide mechanism.

This lateral restoring force can be set to an appropriate value depending on the number of grooves cut parallel to the traveling direction and the ratio of the width of the groove to the convex portion formed by the grooves.
However, by forming grooves in the direction perpendicular to the groove 8, which was provided to obtain the propulsive force necessary for the original conveyance, the groove 8' of the present invention has a propulsive force corresponding to the reduced tooth area. Although it is conceivable that the width of the groove may be reduced, if it is used only as a substitute for the guide bearing 12 for lateral guidance, there is no risk of this because the width of the groove can be sufficiently narrow even if it is quite narrow.

As described above, the pallet truck of the present invention provides an elastic restoring force due to electromagnetic force in any direction in the horizontal plane at the station, so that articles on the pallet truck can be assembled and
When performing work such as processing, it is possible to prevent damage to the product by allowing the trolley to escape even if excessive force is applied, and it also has advantages such as being able to automatically adjust slight deviations during assembly work. It produces a positive effect.

The conveying device of the invention yields further advantages. In other words, if the lattice-shaped grooves provided in the groove portion 8' of the pallet truck are made the same in two orthogonal directions to produce a square tooth row, the result will be exactly the same even when the pallet truck is rotated 90 degrees in the horizontal plane. transport and position control is possible. This not only means that the degree of freedom in processing and assembly at the station is increased, but also allows for many functions that are not possible with the embodiments described above.

The station shown in FIG. 4 is combined with the pallet truck having the square tooth row described above. In the station shown in FIG. 4, the primary winding section 3 of the linear step motor is composed of two sets of winding sections 3' and 3'', which mutually provide vertical thrust. It is divided into four parts, and two sets of winding portions 3' and 3'' are arranged axially symmetrically.

With this combination, the pallet truck can be moved and positioned in two directions within the station, and can be used as a branch point for transportation, as well as being used as a high-precision X and Y table. It becomes possible. It is also possible to apply rotational force by applying thrust in opposite directions to each half of the pallet truck.

In the above embodiment, if the pallet truck does not need to be rotated 90 degrees for use, the pitch of the grooves does not necessarily have to be the same in the two vertical directions, and the pitch of the grooves can be adjusted to form a linear step motor in each direction. Needless to say, it is only necessary that the winding portion is configured. Note that 13 in FIG. 4 is a spherical roller that allows the pallet 10 to rotate freely, and the lateral guide of the orbit outside the station is omitted.

[Brief explanation of drawings]

1 and 2 are a side view and a cross-sectional view of a conveying device having a unidirectional linear step motor, FIG. 3 is a cross-sectional view for explaining part of the principle of the conveying device of the present invention, and FIG. The figure is a plan view of a station portion according to an embodiment of the present invention. 1: Guide, 2: Track, 3: Winding part, 4: Winding,
5: Magnetic core, 6: Trolley, 7: Car, 8: Secondary gutter,
9: Lateral guide wheel, 10: Pallet, 11: Roller, 12: Lateral guide roller, 13: Spherical roller.

Claims (1)

[Claims] 1. A station comprising a plurality of station parts arranged at intervals to apply driving force to the pallet truck, and a track element connecting the station parts to each other, the station part and the pallet truck. In the conveying device, a linear step motor is formed, the driving winding of the linear step motor excites the magnetic pole teeth of the station, and the pallet truck is provided with only the magnetic pole teeth. The magnetic pole teeth on the station side are arranged on the upper surface of the magnetic core arranged in the driving direction of the pallet truck and extending in a direction perpendicular to the driving direction. It is formed by notches provided to form a plurality of grooves extending in the direction, and is excited only by the drive winding. A multifunctional conveyance device using a linear step motor, characterized in that a groove is formed that corresponds to the plurality of windings and cooperates with the plurality of windings to apply a driving force in a direction perpendicular to the driving direction.