JPH01190254A - Magnetic actuator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a magnetic actuator, and particularly to a magnetic actuator that allows a movable body to move in a non-contact manner.

``Prior Art'' Actuators, which are widely used as a means of conveying goods or as a power source for various power devices and control devices, include devices that directly actuate pistons and rods using air pressure or hydraulic pressure. In addition to these, magnetic actuators that utilize magnetic force are also known.

FIG. 11 shows an example of such a magnetic actuator. This magnetic actuator uses air pressure or Δ11 pressure to move the driving body disposed inside the cylinder a, thereby moving the annular moving body C disposed outside the cylinder a using magnetic force. The moving body C is used to transport articles, for example, or to be used as a power source for various purposes.

In this magnetic actuator, the driving body is caused to reciprocate in the axial direction of the cylinder a by air or oil supplied from supply pipes d and d connected to both ends of the cylinder a. This driving body has a plurality of magnets f.
... and a yoke e... magnetized thereby, and the movable body C is equipped with a yoke e of its driving body.
A yoke g is provided, which is magnetized by a magnet g, which attracts each other.

Then, as the driving body moves inside cylinder a,
The movable body C is pulled by the attraction force acting between the yokes e, 1g, . . ., so that it is driven by the driving body.

In this conventional magnetic actuator, since the movable body C is configured to slide on the outer surface of the cylinder a, lubricating oil is used to enable the movable body C to slide smoothly.

"Problems to be Solved by the Invention" By the way, in a magnetic actuator such as the one described above in which the moving body C slides on the outer surface of the cylinder a, it is difficult to completely prevent wear of the sliding parts no matter how much lubricant is used. It cannot be prevented. Then, the abrasion powder generated by the wear scatters around the actuator, and the lubricating oil itself also scatters, which inevitably contaminates the area around the actuator. .

Therefore, if such an actuator is installed in a room that requires extremely high cleanliness, such as a clean room, the cleanliness of the room will decrease due to the abrasion powder and lubricating oil. For this reason, the actuator cannot be directly installed in a room where high cleanliness is required.

Note that this problem always occurs not only when using a magnetic actuator but also when an actuator having a sliding portion is used.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetic actuator that does not scatter abrasion powder or lubricating oil to the surroundings and can be used even in a clean room or the like.

"Means for Solving the Problems" This invention provides for a gap between a drive body disposed inside a cylinder and moved in the axial direction of the cylinder by a drive source, and an outer surface of the cylinder on the outside of the cylinder. and a movable body that moves in the axial direction of the cylindrical body by following the drive body, and the drive body and the movable body move the movable body to the drive body by mutual repulsive force. A pair of first magnets to be driven are provided, and a pair of second magnets are provided to ensure the above-mentioned gap between the movable body and the cylindrical body by repelling or attracting each other. It is characterized by

"Operation" The magnetic actuator of the present invention causes the movable body to follow the drive body by the repulsive force of the pair of first magnets provided in the drive body and the movable body. Further, a gap is maintained between the movable body and the outer surface of the cylindrical body by the repulsion or attraction force of the pair of second magnets provided therein, and the movable body is moved in a non-contact state.

``Embodiment'' L119 A first embodiment of the present invention will be described with reference to FIGS. 1 to 6.

These figures schematically show the structure of the magnetic actuator A of this embodiment, and the reference numeral j in the figures indicates a cylinder. This cylinder l is formed of a non-magnetic material and has a circular cross section, and one end (lower end in FIG. 1) is sealed with a cap 2 to maintain an airtight state, and the other end (upper end) is closed. Motor case song 3 is installed in an airtight condition. A motor 4 is disposed inside this motor casing 3, and a rotation shaft 4 of this motor 4 is provided.
A ball screw mechanism 5 is connected to a by a joint 6. The ball screw mechanism 5 consists of a feed screw 5a that is supported at both ends by bearings 7.7 and is rotatably arranged around the cylinder l circle, and a nut 5b that is screwed onto the feed screw 5a. When the feed screw 5a is rotated by the motor 4, the nut 5b is moved in the axial direction of the cylinder 1 (in the vertical direction in FIG. 1).

A driving body 8 is attached to the nut 5b of the ball screw mechanism 5. The drive body 8 consists of a first magnet 9 and two second magnets 10, 10 arranged above and below it. These first and second magnets 9, 10.10 are each formed in an annular shape, and spacers 11. The inner circumferential surfaces of the magnets 9, 10, and 10 are fixed to the nut 5b with a predetermined distance maintained by the magnets II, so that the outer circumferential surfaces of the respective magnets 9, 10, and 10 can slide on the inner surface of the cylinder 1. As shown in detail in FIG. 2, the first magnet 9 is composed of three permanent magnets 9a and two spacers 9b made of a non-magnetic material interposed between them. (More details later). Further, the second magnet to, 10 is
Permanent magnets 10a... and yokes I that sandwich them
These yokes tab... are magnetized to have an N pole, an S pole, and an N pole, respectively. In addition, between the moving body 8 and the cylinder 1, there are permanent magnets 9a...
A groove 8 formed in the vertical direction on the outer peripheral surface of the yoke 10b...
a... and a projection 1a formed on the inner surface of the cylinder 1 so as to fit into the groove 8a (see FIGS. 3 and 4).

Furthermore, a movable body 12 is disposed outside the cylinder 1. The movable body 12 includes a first magnet 14, which is formed in an annular shape and whose inner diameter is larger than the outer diameter of the cylinder I, and a spacer 16, which are attached to the inside of a tubular body 13 at a predetermined interval. The second magnet I5.15 is located on both sides of the upper and lower sides of the magnet 14.

The first magnet! 4 is annular like the first magnet 9 in the drive body 8, and has a configuration in which a spacer +4b made of a non-magnetic material is interposed between three permanent magnets 14a.

Further, the second magnet 15.15 has a configuration in which a permanent magnet and an electromagnet are combined. That is, this second
Magnet 15.15 is shown in detail in Figure 3.

As shown in FIG. 4, there are a plurality of yokes 15a (eight in this embodiment) that protrude inside the tubular body 13 and are attached radially, and the upper and lower portions of the yokes 15a... Permanent magnets fixed at each tip +
5b... and a coil 15 attached around the center of the yoke 15a... and magnetizing the yoke.
It is composed of c... And yoke 15a
... are permanent magnets 15b... and coils 15c.
. . . so that the tips thereof become N poles, S poles, and N poles, respectively, and the magnetic force thereof can be controlled by the coils 15c .

In addition, a second
Two gap sensors 17, 17 are attached to the positions of the magnets 15, 15, respectively. These gap sensors 17.17 are attached at positions such that their central angles are 90 degrees in plan view (third
(see figure). A control device (path shown) is provided which controls the value of the current flowing through the coils 15c based on the detected value of the gap sensor 17.17 to keep the gap constant in the circumferential direction.

The moving body 12 configured as described above has a second magnet 15
．． 15 are arranged to face the second magnets 10 and 10 of the eight examples of drive bodies, respectively, with the cylinder l in between, and the first magnet 14 is arranged to face the first magnet 9 on the drive body 8 side. (See Figure 2)
. As is clear from the polarity shown in FIG. 2, the first magnets 9 and 14 of each magnet provided in the drive body 8 and the movable body I2 repel each other, and
The second magnets t o and t 5 also repel each other.

Here, to explain in detail the permanent magnets 9a and 14a constituting the first magnets 9 and 14, the permanent magnet 9a on the driver 8 side is as shown in FIGS. 5(a) and 5(b). A large number of trapezoidal permanent magnet pieces 9a are connected together with adhesive or the like as necessary to form a ring shape, and the upper and lower surfaces of the ring are held down by fixing plates 9a, 9at made of non-magnetic material via adhesive or the like. The structure is as follows. Permanent magnet piece 9a
, is magnetized in advance so that the bottom side of the trapezoidal shape becomes the north pole and the top side becomes the south pole, and when assembled in a ring shape, the outer circumferential side becomes the north pole. Further, a collar 9a3 is provided inside the fixed plate 9a. This is to prevent each permanent magnet piece 9a from shifting inward due to the repulsive force from the magnet 14a on the moving body side.

On the other hand, the permanent magnet 14a on the moving body 12 side is as shown in FIG. 6(a).
, (b), the structure is almost the same as that of the permanent magnet 9a on the driving body 8 side described earlier. That is, a large number of trapezoidal permanent magnet pieces 14a.

are connected in a ring shape and held down by fixing plates 14a2, 14a2 from both the upper and lower sides. Contrary to the above description, the permanent magnet pieces 14a have the north pole on the head side, and when assembled in a ring shape, all the inner circumferential sides have the north pole. Also, the collar 14aa of the fixed plate 14a1
is provided on the outer circumferential side.

This is because each permanent magnet piece 14a receives a repulsive force that causes it to shift outward from the permanent magnet 9a on the driver 8 side.

In the above example, the permanent magnets 9a, 14a are constructed by connecting a large number of magnetized pieces 9a, 14a, but the permanent magnets are not limited to this, and may be constructed as a single piece. However, if it is made into one piece, a large-scale magnetization device is required, but if it is made into a multi-divided structure as described above, it has the advantage that it can be manufactured easily without using a large-scale device.

Based on the above configuration, this magnetic actuator A is
This allows the moving body I2 to move without contacting the cylinder l.

That is, since the first magnets 9 and 14 repel each other, when the driving body 8 moves upward in the cylinder 1 by the ball screw mechanism 5, the repulsive force causes the movable body 12 to move upward.
follows the driving body 8 and moves upward. Specifically, as shown in Figure 2, since the first magnets 9 and 14 are deviated from each other in the radial and height directions, the repulsive force F of both acts in an oblique direction, and some of them are vertical. The movable body 12 is moved upward by the component F1. On the other hand, when the driving body 8 is lowered, the support due to the repulsive force of the first magnet is lost, and the moving body 1
2 follows the driving body 8 and descends due to its own weight.

Furthermore, since the second magnets 10.15 repel each other, the movable body 12 is urged toward the outside in the radial direction of the cylinder l.
As a result, the axes of the movable body 12 and the cylinder l coincide, and a gap 1 is formed between the movable body 12 and the outer surface of the cylinder at a predetermined interval uniform throughout the circumferential direction of the cylinder l.
8 can always be secured.

When an external force is applied to the movable body 12 and the dimensions of the gap 18 change, the change is detected by the gap sensor 17.17, and based on the detection result, a predetermined coil is By controlling the current value of 15c, the second magnet 15.1 of the moving body I2
The magnetic force or repulsive force of the gap star 8 can be controlled, and therefore the dimensions of the gap star 8 can always be kept at a constant value.

In addition, the magnetic actuator A uses magnets that repel each other to the first magnet that has the function of moving the movable body 12, and the horizontal component F of these repulsive forces is the same as that of the second magnet 10.15. As in the case of , a centripetal action is generated to align the axis of the moving body 12 with respect to the cylinder l.

Therefore, as a result of reducing the burden on the guiding function (magnetic levitation function) of the moving body 12 performed by the second magnet 10.15,
It becomes possible to strengthen the repulsive force of the first magnet, and the driving force due to its component F1 can be increased.

Incidentally, when the first magnets 9 and 14 are of the attraction type, when the moving body 12 shifts from the center of the cylinder l, the attraction force by the first magnets 9 and 14 is such that the magnetic force is equal to the distance. Since it is inversely proportional to the square of the square, it becomes larger in places where the distance becomes shorter, and therefore the attraction force increases even more as the distance approaches. This creates a very unstable situation, but in order to avoid this, the second magnet 1
0.15, a larger and more powerful magnet must be used to overcome the attractive force of the first magnet 9.14, in which case there is a problem that the device itself becomes larger. Furthermore, if the second magnet 10.15 cannot be made very strong for various reasons, the first magnet 9.14 must have a certain degree of weak magnetic force, and in that case, As a magnetic actuator, it becomes impossible to obtain a large driving force.

In contrast, if a repulsive type first magnet is used as described above, the first magnet itself has a centripetal action, so the device itself does not become large and an actuator with a large driving force can be obtained.

As mentioned above, in this magnetic actuator A,
Since there is no part of the moving body 12 that always slides in a non-contact state with the cylinder 1, there is no wear at all. Also,
Therefore, no lubricant is required. Therefore, unlike conventional actuators, wear particles and lubricating oil do not scatter and contaminate the surrounding area. For this reason, it becomes possible to install it even in highly clean rooms such as clean rooms, which could not be installed conventionally.

Note that inside the cylinder 1, the feed screw 5a and the nut 5b, as well as the inner surface of the cylinder 1 and the outer peripheral surface of the driver 8, are in contact with each other, so there is a risk that they will wear out. Although it is necessary to use lubricating oil for these, since the inside of the cylinder 1 is sealed by the cap 2 and the motor casing 3, wear particles and lubricating oil are not scattered to the outside of the cylinder 1.

Although the first embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and the configuration of each magnet and its polarity are limited to the above, and various design changes are possible as follows. It is.

For example, in the above case, the second magnet of the moving body I2! Although No. 5 has a structure in which a permanent magnet and an electromagnet are combined, this may be formed only with an electromagnet without using a permanent magnet.

Moreover, although the second magnets 10.15 are assumed to repel each other in the above description, the gap can be similarly secured even if the second magnets 10.15 are attracted to each other. In this case, one of the second magnets 10.15 (on the driving body side or the movable body side) may be made of a magnetizable material, such as an iron piece, instead of being a magnet.

Furthermore, the shape of the cylinder 1 is not limited to having a circular cross section, but may also have a rectangular cross section, for example, in which case,
The driving body 8 and the movable body 12 may also have shapes corresponding to the shape of the cylinder l. In addition, although a ball screw mechanism is used as the drive source for the drive body in the above example, it is not limited to this, and any suitable means may be used, such as driving with a wire or chain, or using hydraulic pressure or pneumatic pressure. can.

It is of course possible to use the magnetic actuator A with the cylinder vertically to move the movable body 12 up and down, or with the cylinder horizontally or tilted at an arbitrary angle.

Second Example Next, we will discuss the second example in which the magnetic actuator of the present invention is applied to a conveyance device in a clean room.
This will be explained with reference to FIGS. In this transfer device, the magnetic actuator A explained in the first embodiment is used as is, and the explanation of the magnetic actuator A will be simplified by assigning the same reference numerals to the same components as those explained in the first embodiment. become

This conveyance device takes articles in and out of storage shelves installed on both sides of the rail R, and includes a base B running on the rail R, and two shelves installed on both left and right ends of the base B. The magnetic actuator A of the book.

A, a frame F that is moved up and down by the magnetic actuator A, and a slide arm S that is movably provided on the frame in a direction perpendicular to the rail R and that suspends the article G at its tip. It can be moved in three axes by remote control by a human or automatically by a computer program, and each sliding part has a non-contact structure.

The left and right magnetic actuators A, motors 4.4 disposed in the upper motor casings 3.3 of A are interlocked with each other and rotated in synchronization. Furthermore, the frame F is attached to the moving body 12 of the magnetic actuator A.

This frame F has a long side 21 along the longitudinal direction of the base B.
, 21 and short sides 22, 22 connecting both ends thereof, it is formed into a mouth shape in plan view, and is connected to the movable body 12 by a connecting portion 23 protruding from the center of the short sides 22, 22. Note that this frame F has a lightweight and sturdy structure, and its material is selected so as not to exert magnetic influence on the moving body 12 and the like.

A support member 26 consisting of a pair of vertical parts 24, 24 and a horizontal part 25 connecting the upper ends thereof is erected on the upper surface of the long sides 21, 21 of the frame F, and the horizontal part on each long side 2+, 2+ A guide member 27 is installed between 25 and 25. A guide rail 28 having an inverted T-shaped cross section is formed on the lower surface of this guide member 27, and this guide rail 28 has a slide arm having a groove 29 on the upper surface shaped to fit with this guide rail 28. S is attached so as to be movable in a direction perpendicular to the rail R. In this guide member 27 and slide arm S, magnets (shown in the figure) that attract each other are attached to appropriate positions facing the guide rail 28 and groove 29, and the magnetic levitation force prevents contact between the two. method is adopted. A gap sensor (shown in the diagram) is provided to detect the gap between the guide rail 28 and the groove 29, and the attraction force of the magnet is adjusted based on the value. A well-known linear motor (path shown) is used as the drive source. An electromagnet 31 is disposed on the lower surface of the left and right ends of the slide arm S to detachably attract a magnetic piece 30 attached to the upper surface of the stored article G.

The rail R has upper and lower horizontal parts 3 as shown in FIG.
2.33 and the vertical portion 34 to form a single-shaped cross section, and on the other hand, a groove 35 shaped to fit the rail R is formed on the lower surface of the base B. Electromagnets 36, 36 and 37, 37 are installed at the lower bottom and side parts of this 'tli 35, respectively, to support the load of the base B or control its posture by attracting the upper horizontal part 32 of the rail R. The suction force is adjusted based on the detected value of the gap sensor (path shown) to prevent contact between the two. Further, a coil 38 is disposed at the upper bottom of the groove 35, so that the rail R
A linear motor L configured to generate a high current in the upper horizontal portion 32 of the L and generate a magnetic field to move the two relative to each other.
M is placed.

Rail R1 Base B1 Magnetic actuator A as above
Based on the structure consisting of one slide arm S, this conveyance device can take articles G into and out of storage shelves in a state where there are no sliding contact parts.

With this conveyance device, for example, in order to take out an article G from a storage shelf, the base B is moved to the required position with the slide arm S shortened, and then the magnetic actuator A is activated to raise the height of the frame F. After adjusting the slide arm S and positioning the electromagnet 31 slightly above the magnetic piece 30, actuate the magnetic actuator A again and lower the frame F a little to bring the electromagnet 31 into close contact with the magnetic piece 30. Activate the electromagnet 31. Then, the above process is performed in reverse to shorten the slide arm S, the base B is moved to a required position, and the same process is performed to lower the article G, thereby completing the operation.

During this working process, in the magnetic actuator A, the two motors 4.4 rotate synchronously, so that the driving body 8.8 and the movable body 12.12 are always at the same height, so that the frame F parallelism is maintained.

In the above-mentioned conveyance device, since there is no part where the movable body 12 always slides in a non-contact state with the cylinder 1, there is no wear at all, and therefore no lubricating oil is required. Therefore, unlike conventional lifting devices, wear particles and lubricating oil do not scatter and contaminate the surrounding area, and it can be installed in highly clean rooms such as clean rooms, which were previously impossible to install. becomes.

"Effects of the Invention" In the magnetic actuator of the present invention, since the driving body and the movable body are provided with a pair of first magnets that repel each other and a pair of second magnets that repel or attract each other, the movable body It can move while maintaining a non-contact state, and not only does it not scatter abrasion powder unlike conventional actuators, but it also does not require the use of lubricating oil, so the lubricating oil does not scatter. Therefore, this actuator has no fear of contaminating the surrounding area, and therefore can be installed even in highly clean rooms such as clean rooms, which could not be installed in the past.

In particular, as mentioned above, the first pair of magnets is not an attractive type but a repulsive type, and by using a repulsive type magnet in this way, the movable body is shifted from the center of the cylindrical body. In this case, a force (centripetal force) acts to return the movable body to be concentric with the cylindrical body.As a result, magnetic levitation is stabilized and an actuator with a large driving force can be obtained. .

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a cross-sectional view showing the overall schematic structure of a magnetic actuator, FIG. 2 is an enlarged cross-sectional view of the main parts thereof, and FIG. Figure 4, which is a cross-sectional view along line ■-■ in Figure 2, is IV in Figure 2.
5 (a) and (b) are detailed views of the first magnet on the driver side, and FIG. 6 (a) and (b)
is a detailed view of the first magnet on the moving body side. 7 to 10 show a second embodiment of the present invention, in which FIG. 7 is a perspective view showing the entire conveying device, FIG. 8 is a front sectional view thereof, and FIG. 9 is a side sectional view. FIG. 10 is a plan sectional view. Further, FIG. 1I is a sectional view showing an example of a conventional lifting device. A... Lifting device, B... Base, 1...
... Cylinder (cylindrical body), 5 ... Ball screw mechanism (drive source), 8 ...
...Driver, 9.14...First magnet, 10, l 5...Second magnet, I2...
- Moving object, I8...Gap. Applicant Ishikawajima Harima Heavy Industries Co., Ltd. Figure 2 Figure 6 (.) 1.4a Figure 6 (1)) Figure 5 (a) Figure 5 (b) Figure 10 Figure 11

Claims (1)

[Claims] A drive body disposed inside the cylinder and moved in the axial direction of the cylinder by a drive source, and a drive body disposed outside the cylinder with a gap between the outer surface of the cylinder and driven by the drive body. and a movable body that moves in the axial direction of the cylindrical body, and the drive body and the movable body are provided with a pair of first magnets that cause the movable body to follow the drive body by mutual repulsive force. A magnetic actuator comprising a pair of second magnets that secure the gap between the movable body and the cylindrical body by repelling or attracting each other.