JPH08112733A - Transport positioning device - Google Patents

Abstract

PURPOSE: To provide a transport positioning device which cuts off the mechanical coupling between a shaft and a movable stand by means of magnetic screws and improves the precision of a stop position even when outer force is exerted. CONSTITUTION: This device possesses a movable stand 2 on which a transport object is to be mounted; a shaft 3 provided in parallel with the movement direction of the movable stand 2; an outer pipe magnet that is fixed at the shaft 3 and has spiral magnetization on its inner surface; an inner pipe magnet that is provided on the outer surface of the shaft 3 and is positioned in penetration of the outer pipe magnet and at the same time has spiral magnetization on its outer surface; a step motor 8 that is provided at one end of the shaft 3 and rotates the shaft 3; and a stopper 9 that can protrude into the movement passage of the movable stand 2. When the movable stand 2 butts against the stopper 9 and stops, overrun control in which the step motor 8 is further operated by a predetermined delivery amount and stoppage is made, is conducted, and the positioning of the movable stand 2 is carried out by means of the reaction of the magnetic screws.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transport positioning device for stopping an object to be transported at a target position, and more particularly to a transport positioning device using a spring of a magnetic screw to improve positioning accuracy. Things.

[0002]

2. Description of the Related Art In an assembly plant, an apparatus for transporting articles such as product parts between processes is used. Some of the transporting devices are intended to position and stop at a specific place in order to process the transporting object. FIG. 12 shows an example of such a transport positioning device that has been conventionally used. The transport positioning device includes a screw shaft 51 having a surface formed with a screw, and a movable table 52 formed through a screw hole screwed into the screw.
And have. A step motor 53 is provided at one end of the screw shaft 51 so that the screw shaft 51 can be rotated. Further, on both sides of the screw shaft 51, receiving shafts 54, 54 are provided in parallel with the screw shaft 51,
The movable table 52 is slidable with respect to the receiving shafts 54, 54.

In such a transport positioning device, when an object to be transported is placed on a movable table 52 and a screw shaft 51 is rotated by a step motor 53, the movable table 52 is screwed to transport the object to a desired position. it can. And at that place,
The stop position of the movable base 52 is held by the braking force of the step motor 53. Further, since the weights of the movable table 52 and the object to be conveyed are carried by the weight receiving shafts 54, 54 and do not apply to the screw shaft 51, the rotation of the screw shaft 51 by the step motor 53 is smooth. This transport positioning device is provided with a step motor 53 capable of controlling the rotation angle with high accuracy by using pulses.
Is used as the driving means of the screw shaft 51 to improve the positioning accuracy of the movable table 52. Usually, this transport positioning device is used by providing a stopper in a moving passage of the movable table 52, and stops the movable table 52 by contacting the movable table 52 with the stopper. At this time, step-out occurring in the step motor 53 is detected, and the operation of the step motor 53 is stopped to be in a holding state.

An example of another conventional transport positioning device is shown in FIG.
Shown in This transport positioning device utilizes magnetic screws instead of mechanical screws. The transport positioning device shown in FIG. 13 has a magnetic screw shaft 6 whose surface is spirally magnetized.
0 and a movable base 63 having a spirally magnetized magnetic screw hole 61 on its inner surface, and the magnetic screw shaft 60 has a magnetic screw hole 6
1 with a certain gap. Further, a slide shaft 62 is provided in parallel with the magnetic screw shaft 60, and holds the movable base 63 slidably and carries a load. Further, a motor 64 is provided as a driving means of the magnetic screw shaft 60, and the rotational drive is transmitted to the shaft core 66 of the magnetic screw shaft 60 via the belt 65.

In this transport positioning device, the magnetic screw shaft 6
A magnetic screw is constituted by 0 and the magnetic screw hole 61, and the movable table 63 is screwed by rotating the magnetic screw shaft 60 by the motor 64. In this transport positioning device, the magnetic screw shaft 60 and the magnetic screw hole 61 are not mechanically coupled to each other and form a magnetic screw having a spring property.
3 has the feature that the movement is flexible.

[0006]

However, since the screw shaft 51 and the movable base 52 are mechanically connected to each other by the screw mechanism in the transfer positioning device shown in FIG. 12, the following problems are encountered. I was First, the screw shaft 51 and the movable base 52
There is inevitably a backlash in the mechanical screw mechanism. Therefore, even when the movable table 52 is brought into contact with the stopper and stopped, the backlash causes
The stop position 2 has a variation of about ± 0.05 mm. For this reason, the required positional accuracy cannot be obtained.

Further, when the transfer positioning device is used in an assembly factory, an external force may be applied to the movable table 52. In particular, when an external force acts on the screw shaft 51 in the axial direction, the external force is transmitted to the step motor 53 via the screw shaft 51. However, since the braking force of the step motor is generally weak, the step motor 53 easily steps out due to an external force. In that case, the step motor 53 must be once rotated in the reverse direction and then reset to the predetermined position again, which is complicated. In the transfer positioning device shown in FIG. 13, since the magnetic screw is used, the problem caused by the mechanical screw connection is solved, but the positional accuracy when the movable table 63 is stopped is insufficient.

The present invention has been made to solve the above-mentioned problems of the prior art. The mechanism of the magnetic screw is used to cut off the mechanical coupling between the shaft and the movable base, and An object of the present invention is to provide a transport positioning device that uses spring properties to improve the accuracy of the stop position even when an external force is applied.

[0009]

In order to achieve this object, a transport positioning device according to the present invention comprises a movable table on which an object to be transported is mounted, a rotating shaft provided in parallel to the moving direction of the movable table, and a movable table. A first cylindrical magnet fixed to the base and having a helical magnetization on the inner surface, and a second cylinder provided on the outer surface of the rotating shaft and positioned through the first cylindrical magnet and having a helical magnetization on the outer surface What is claimed is: 1. A transport positioning device comprising: a magnet; and a driving unit provided at one end of a rotating shaft for rotating the rotating shaft. Overrun control means for stopping the driving means by driving it by a predetermined feed amount when the driving means stops.

[0010] Further, according to the present invention, there is provided the transport positioning device, wherein the predetermined feed amount is 0.5.
The pitch is equal to or less than the pitch. Further, the transport positioning device of the present invention is the transport positioning device, wherein the drive means is a step motor or a DC.
It is configured to be a motor.

[0011]

In the transport positioning device of the present invention having the above-mentioned structure, when the rotating shaft is rotated by the driving means, the first cylindrical magnet provided on the rotating shaft also rotates. Therefore, the movable table is advanced by the magnetic action of the helical magnetization on the outer surface of the first cylindrical magnet and the helical magnetization on the inner surface of the second cylindrical magnet. As a result, the transport target placed on the movable base is transported to a desired position. When the stop means is projected into the moving passage of the movable table and the movable table comes into contact with this, the overrun control means causes the drive means to further rotate the rotary shaft by a predetermined angle. As a result, a reaction force is generated in the magnetic screws of the first cylindrical magnet and the second cylindrical magnet, and the movable table is pressed against the stopping means by the reaction force.
Positioned.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the configuration of the transport positioning device 1. The transport positioning device 1 shown in FIG. 1 basically includes a long rectangular base 10 on which a shaft 3 and two slide rods 4, 4 are provided in parallel with each other, and a movable base 2 movable along these shafts. And the shaft 3
And the movable table 2 constitute a magnetic screw mechanism described later.
The shaft 3 is rotatably held at both ends by bearings 22, 22. A step motor 8 is provided at one end of the shaft 3 so that the shaft 3 can be rotated. A stopper 9 is provided on the side of the base 10 so as to protrude the movable iron core 23 into the movement passage of the movable base 2 to restrict the movement of the movable base 2 and perform positioning. Further, the step motor 8 is provided with a controller 16 described later.

FIG. 4 shows a sectional view of the portion AA 'in FIG. The movable base 2 is a substantially rectangular parallelepiped member, on which an object to be transported (not shown) is placed. Bushings 21, 21 for reducing sliding friction with the slide rods 4, 4 are attached to the lower surface of the movable base 2. Further, a cylindrical outer cylinder magnet 5 is fixedly attached to the movable base 2 via a jacket 7. The shaft 3 having the core rod 11 and the inner cylinder magnet 6 is provided inside the outer cylinder magnet 5.
Has penetrated. The inner cylinder magnet 6 of the shaft 3 and the outer cylinder magnet 5 of the movable base 2 constitute a magnetic screw. The two slide rods 4 and 4 are fixedly attached to the upper surface of the base 10. The slide rods 4 carry the load of the movable base 2 and the object to be conveyed placed thereon, and have a role of guiding the movable base 2 to move in the axial direction.

Here, the outer cylinder magnet 5, which constitutes a magnetic screw,
The inner cylinder magnet 6 will be described. A cross-sectional perspective view of the outer cylinder magnet 5 is shown in FIG. The outer cylinder magnet 5 is a cylindrical magnet,
The inner surface has an even number of magnetized bands 17 formed in a spiral shape. Adjacent magnetized bands 17 have opposite magnetization polarities. That is, if the N pole is magnetized in a certain magnetizing band 17, the S pole is magnetized in the adjacent magnetizing band 17. And, on the outer peripheral surface of the outer cylinder magnet 5,
The engaging portion 12 is formed in a ridge shape. This is to prevent the outer cylinder magnet 5 from shifting in the direction around the axis with respect to the jacket 7 of the movable base 2.

FIG. 6 shows a perspective view of the inner cylinder magnet 6. The inner cylindrical magnet 6 is a cylindrical magnet substantially similar to the outer cylindrical magnet 5, but a magnetized band 18 is formed on the outer surface. In addition, the outer magnet 5 has an outer diameter slightly smaller than the inner diameter. And
Engagement portions 13 are formed in a ridge shape on the inner peripheral surface of the inner cylindrical magnet 6. This is to prevent the inner cylindrical magnet 6 from being displaced in the direction around the axis with respect to the core rod 11. The azimuth angle θ of the spiral magnetization and the width of the magnetized body are adjusted so that the magnetized bands of opposite polarities are opposed to each other between the outer cylinder magnet 5 and the inner cylinder magnet 6, and the two constitute a magnetic screw. In addition, both the outer cylinder magnet 5 and the inner cylinder magnet 6 may be configured such that the height of the cylinder (indicated by h in FIGS. 5 and 6) is short, and a large number of these cylinders are arranged vertically. As a result, the degree of freedom in designing the outer tubular magnet 5 and the inner tubular magnet 6 can be increased.

In the magnetic screw formed by inserting the inner cylinder magnet 6 inside the outer cylinder magnet 5, when no external force is applied, the magnetized bands of opposite polarities attract each other as shown in FIG. ,
It is located opposite. FIG. 9 is a conceptual diagram showing a state in which the magnetized bands of the outer cylinder magnet 5 and the inner cylinder magnet 6 face each other. FIG.
As shown by p in the figure, the width of one magnetized band in the axial direction is called one pitch. When the inner cylindrical magnet 6 is rotated around the axis, the magnetized band 18 advances. Therefore, in order to maintain the facing state between the magnetized band 17 and the magnetized band 18, the outer cylindrical magnet 5 is also advanced by that amount. I do. For this reason, it is called a magnetic screw. On the other hand, when an external force is applied in the axial direction, the outer cylinder magnet 5 and the inner cylinder magnet 6 are not mechanically coupled, so that the positional relationship between the magnetized bands 17 and 18 is deviated, As a result, a reaction force is generated by the magnetic force. That is, the magnetic screw has a spring property. Details of the spring property of the magnetic screw will be described later.

Next, the shaft 3 will be described with reference to FIG. The shaft 3 is a substantially cylindrical core rod 1
1, the inner cylinder magnet 6 is fitted. The core rod 11 is formed in a round rod made of a magnetic material such as iron by a groove 14 in an axial direction.
14 is formed. The reason for using the magnetic material is to effectively use the magnetic force of the inner cylindrical magnet 6. Grooves 14, 1
Reference numeral 4 is used to prevent the core rod 11 and the inner cylindrical magnet 6 from being displaced from each other around the axis by engaging with the engaging portions 13 on the inner peripheral surface of the inner cylindrical magnet 6. When assembling the shaft 3, one or two or more inner cylinder magnets 6 before magnetizing are fitted to the core rod 11, and then spiral magnetizing is performed. The shaft 3 is rotatably held at both ends by bearings 22 and 22, and is rotated by a step motor 8.

Next, attachment of the outer cylinder magnet 5 to the movable table 2 will be described with reference to FIG. The outer cylinder magnet 5 is fixedly attached to the movable base 2 via the jacket 7 as described above. The jacket 7 is a magnetic member for effectively and effectively using the magnetic force of the outer cylinder magnet 5. The jacket 7 is provided with grooves 15, 15 for engaging with the engaging portions 12, 12 on the outer peripheral surface of the outer cylindrical magnet 5 and preventing the magnets from shifting from each other. The movable base 2 holds the outer cylindrical magnet 5 together with the jacket 7.

Next, the stopper 9 will be described. The stopper 9 is a solenoid device that protrudes the movable iron core 23 into the moving passage of the movable base 2 to restrict the movement of the movable base 2 and perform positioning. The stopper 9 is provided on a rail 28 provided in parallel with the base 10, and can be moved to the left or right while keeping a constant distance from the base 10. The stopper 9 includes a solenoid 25, a movable iron core 23 movably provided with respect to the solenoid 25, and a solenoid 2.
5 and a fixed iron core 24 fixed to No. 5. A disk-shaped flange 26 is attached to the tip of the movable iron core 23. A return spring 27 is interposed between the bobbin around which the solenoid 25 is wound and the flange 26, and the return spring 27 is separated from the bobbin, that is, in the direction in which the movable core 23 is separated from the fixed core 24. It is energizing.

When the solenoid 25 is not energized, the movable core 23 is not attracted to the fixed core 24.
The movable core 23 is fixed to the fixed core 2 by the urging force of the return spring 27.
It is separated from 4 and protrudes into the moving passage of the movable table 2. When the solenoid 25 is energized, the movable core 23 and the fixed core 24
Since a magnetic attraction force exceeding the biasing force of the return spring 27 is generated between and, the movable iron core 23 is attracted to the fixed iron core 24,
The movable base 2 is retracted from the moving passage.

Next, the controller 16 will be described with reference to the block diagram of FIG. The controller 16
A pulse drive 29 for generating a drive pulse, a CPU 31 for performing various arithmetic processes, a RAM 32 for temporarily storing arithmetic data,
ROM 3 for storing control programs and numerical tables
3. An interface 30 connecting them. The CPU 31 performs various calculations based on the contents stored in the ROM 33, etc., and the pulse drive 29
Transmits a drive pulse to the step motor 8, and the step motor 8 is driven. A representative one of the programs stored in the ROM 33 is an overrun program 34.

Next, the operation of the transport positioning device 1 having the above configuration will be described. The transport positioning device 1 is intended to move the movable table 2 in the axial direction by rotating the shaft 3 with a step motor 8. When the shaft 3 is rotated by the step motor 8, the inner cylindrical magnet 6 is rotated accordingly. Therefore, the movable base 2 holding the outer cylinder magnet 5 moves in the axial direction by the screwing action of the magnetic screw. In the transport positioning device 1, since the step motor 8 is used as the rotation driving means of the shaft 3, the rotation angle can be controlled by the drive pulse control performed by the controller 16, and the movable table 2 is moved and mounted as desired. The transport target can be transported.

When the stop position of the movable base 2 is precisely positioned, the stopper 9 is used. That is, the stopper 9 is moved on the rail 28 so that the movable base 2 is stopped. When the stopper 9 moves, the solenoid 25 is energized, and the movable iron core 23 is retracted from the moving passage of the movable base 2. When the solenoid 25 is de-energized at that position, the distal end of the movable iron core 23 projects into the movement passage of the movable base 2 by the urging force of the return spring 27, and the movement of the movable base 2 is restricted. In this state, when the stepping motor 8 is driven to move the movable base 2 and abut on the tip of the movable iron core 23, the movable base 2 stops at that position. This state is shown in Figure 2.
Shown in

When the step motor 8 is further driven slightly, the shaft 3 rotates a little while the movable table 2 is stopped, so that the positional relationship between the magnetized bands of the outer cylinder magnet 5 and the inner cylinder magnet 6 is slightly shifted. Becomes FIG. 10 shows this state. FIG. 10 shows a state in which the magnetized bands oppose each other when the outer cylinder magnet 5 shown by the solid line is not stopped by the stopper 9, and the outer cylinder magnet 5 shown by the broken line is stopped by the movable iron core 23, and the displacement Δx Shows the state in which the occurrence has occurred. In this state, it can be considered that the movable iron core 23 applies an external force in the axial direction to the movable table 2 to cause a deviation Δx. In the state where the displacement Δx is generated, the reaction force F is generated due to the spring property of the magnetic screw, and the movable table 2 is pressed against the movable iron core 23 by the reaction force F and becomes immobile. Therefore,
By placing the stopper 9 in the correct position, the movable table 2 can be precisely positioned.

FIG. 1 shows the relationship between the displacement Δx and the reaction force F.
This will be described with reference to the graph of FIG. FIG. 11 is a graph in which the displacement Δx is plotted on the horizontal axis and the reaction force F is plotted on the vertical axis. As shown in this graph, near the origin, the reaction force F acts in the opposite direction to the shift Δx, and its magnitude increases with the shift Δx. That is, it shows the spring property of the magnetic screw. And
When the magnitude of the displacement Δx reaches 0.5p, the magnitude of the reaction force F becomes maximum. Therefore, the magnetic screw exerts the spring property when the displacement Δx is within the range of ± 0.5p. Recognize. The maximum value Fmax of the reaction force F can be arbitrarily selected by a combination of the outer cylinder magnet 5 and the inner cylinder magnet 6. In this embodiment, the maximum value Fmax is set to about 3.8 kgf.

In the transport positioning device 1, the controller 1
6 executes the overrun program 34 of the ROM 33 to obtain such a state. That is, the movable base 2 is
, The shaft 3 is overrun by a predetermined angle by the step motor 8. The amount of overrun is preferably set to 0.5p or less. As an example, if the step motor 8 has 200 pulses / rotation, such overrun can be realized by operating about 20 to 30 pulses.
As a result, the magnitude of the deviation Δx becomes about 0.25p, and the movable table 2 is pressed against the movable iron core 23 by the reaction force Fs of about 2 kgf (indicated by point Q in FIG. 11).

In this state, even if there is a slight error due to the stop accuracy of the step motor 8 itself, the error is deviated Δ.
x means the variation of the reaction force F. If the reaction force F is about 0.5 kgf or more, it hardly affects the stop position of the movable table 2. If the amount of overrun is about 30 ° or more, a sufficient reaction force F can be obtained. Therefore, an accuracy of about 0.001 mm is obtained as the stop position, and the positioning is reliable. On the other hand, the upper limit of the amount of overrun is a range that does not exceed the maximum value of the magnitude of the reaction force F (see FIG.
If it is 0.5p) in the graph of 1, there is no problem. However,
When the angle exceeds 60 °, the reaction force F becomes large, so that the rigidity of the movable table 2 and the stopper 9 and the braking force of the step motor 8 need to be increased.

Since the inner cylinder magnet 6 and the outer cylinder magnet 5 are not mechanically connected, the step motor 8 itself does not lose synchronism. Therefore, there is no need to perform operations such as resetting. In addition,
Since the movable table 2 is supported by the two slide rods 4, 4, only one side of the movable table 2 is movable as shown in FIG.
Even when the movable table 2 abuts on the movable table 2, the movable table 2 is not twisted.

As described in detail above, according to the transport positioning device 1 of the above-described embodiment, the movable table is formed by using the magnetic screw constituted by the spirally magnetized outer cylinder magnet 5 and inner cylinder magnet 6. Since the screw 2 is made to advance, the movable table 2 can be moved to a desired position by rotating the shaft 3 by the step motor 8, and the object to be conveyed can be conveyed. Further, since the movable iron core 23 of the stopper 9 is made to protrude into the moving passage of the movable base 2 and is brought into contact with the movable base 2 to stop, the movable base 2 is stopped by the reaction force of the magnetic screw having a spring property.
Is pressed against the movable iron core 23, and high stop position accuracy is obtained. Furthermore, even if external force is applied to the movable table 2,
Since the movable base 2 and the shaft 3 are not mechanically connected to each other, the force is transmitted to the stepping motor 8 and no step-out occurs. Here, outer cylinder magnet 5, inner cylinder magnet 6
Since the engaging portions 12 and 13 are respectively provided in the above to engage with the groove 15 of the jacket 7 and the groove 14 of the core rod 11, the outer cylindrical magnet 5 and the inner cylindrical magnet 6 do not shift in the axial direction.

The above embodiment does not limit the present invention in any way, and it goes without saying that various modifications and improvements are possible without departing from the gist of the present invention. For example, the step motor 8 is used as the drive means for the shaft 3, but any other motor may be used as long as it has a holding function, such as a DC motor. Further, the stopper 9 may be one that operates with compressed air instead of a solenoid. Also, ridge-shaped engaging portions 12 and 13 are provided on the outer cylinder magnet 5 and the inner cylinder magnet 6, and instead of engaging with the jacket 7 and the grooves 15 and 14 of the core rod 11, grooves are formed on the outer cylinder magnet 5 and the inner cylinder magnet 6. And a ridge-shaped engaging portion may be provided on the jacket 7 and the core rod 11.

[0031]

As is apparent from the above description, according to the transport positioning apparatus of the present invention, the movable table is screwed by the rotating shaft using the mechanism of the magnetic screw.
The movable table can be moved to a desired position by driving the driving means. Further, since the rotating shaft and the movable base are not mechanically coupled, the external force applied to the movable base is not transmitted to the driving means. In addition, a stop means that can protrude is provided in the moving passage of the movable table, so that the movable table is brought into contact with the stop means and the rotating shaft is slightly overrun, so that the movable table is pressed against the stop means by the reaction force of the magnetic screw. , High stopping position accuracy can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a transport positioning device according to the present embodiment.

FIG. 2 is a diagram showing a state in which a movable table is brought into contact with a stopper in the transport positioning device shown in FIG. 1;

FIG. 3 is a block diagram illustrating a control system of the transport positioning device.

FIG. 4 is a cross-sectional view showing a configuration of the transport positioning device shown in FIG.

FIG. 5 is a sectional perspective view of an outer cylinder magnet.

FIG. 6 is a perspective view of an inner cylinder magnet.

FIG. 7 is a diagram illustrating a configuration of a shaft.

FIG. 8 is a diagram showing an outer cylinder magnet and a jacket.

FIG. 9 is an explanatory diagram showing a facing relationship of magnetized bands in a magnetic screw.

FIG. 10 is a diagram illustrating a state in which displacement occurs in a magnetic screw.

FIG. 11 is a graph showing a relationship between displacement and force of a magnetic screw.

FIG. 12 is a plan view showing a configuration of a conventional transport positioning device.

FIG. 13 is a diagram showing a configuration of another conventional transport positioning device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conveying positioning apparatus 2 Movable stand 3 Shaft 5 Outer cylinder magnet 6 Inner cylinder magnet 8 Step motor 9 Stopper 10 Base 16 Controller 17, 18 Magnetization zone

Claims (3)

[Claims] 1. A movable table on which an object to be conveyed is placed, a rotating shaft provided in parallel with the moving direction of the movable table, and a first cylinder fixed to the movable table and having a spiral magnetization on an inner surface. A second magnet provided on the outer surface of the rotating shaft and penetrating the first cylindrical magnet and having a helical magnetization on the outer surface;
In a transport positioning device having a cylindrical magnet and a drive unit that is provided at one end of a rotary shaft and rotates the rotary shaft, a stop unit that can project into a moving path of the movable base, and the movable base contacts the stop unit. Stop when
Overrun control means for operating the drive means for a predetermined feed amount and stopping the drive means. 2. The transport positioning device according to claim 1, wherein the predetermined feed amount is 0.5 pitch or less. 3. The transport positioning device according to claim 1, wherein the driving unit is a step motor or a DC motor.