JPS6360636B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic levitation guide mechanism that maintains a relatively movable reference shaft and an electromagnet fixing body in a non-contact state by magnetic attraction.

Traditionally, storage devices for machine tools and information communication equipment,
For example, a magnetic disk device or an optical disk device uses a guide mechanism for accurate positioning. For this guide mechanism, it is necessary to minimize the frictional force that degrades its performance, and for this reason, systems using bearings that support the movable body without metal contact using hydraulic or air pressure have been put into practical use. .

However, maintenance work on the compressor and piping system is important for bearings in such guide mechanisms, and this is a major factor that affects reliability. This type of guide mechanism is also used in integrated circuit processing equipment that requires highly accurate positioning, but such processing equipment is extremely sensitive to dust, so extreme care must be taken when using lubricating media. Furthermore, since the machining work is carried out in a vacuum, it may not be possible to use a guide mechanism using air bearings.

Therefore, recently, a magnetic levitation guide mechanism shown in FIG. 1 has been proposed as a means to solve this problem. That is, 1 is a movable body, 2 is a guide, and the movable body 1 is provided with, for example, four electromagnets 3 to 6, whose magnetic pole faces are indicated by diagonal lines on the upper and lower surfaces, and the magnetic pole faces are also indicated by diagonal lines on both sides. For example, 2
A total of 12 electromagnets are provided by arranging two electromagnets 7 and 8, respectively. In this case, the electromagnets on the top and bottom surfaces, the left side and the right side are arranged in symmetrical positions, and the individual electromagnets 3, 4,
5... is equipped with a detector 9 (however, only the electromagnet 3 is shown in the figure) for detecting the gap with the guide 2. The coil current of each electromagnet 3, 4, 5... is controlled by the signal from the accompanying detector 9, and the magnetic attraction force at this time supports the movable body 1 with respect to the guide 2 in a non-contact state, and guides the movable body 1. Keep the gap between 2 and 2 constant. The movable body 1 is moved in the direction of the movement axis 10 by a driving force such as a linear motor (not shown).

According to such a magnetic levitation guide mechanism, the movable body 1
can be supported without contacting the guide 2,
The disadvantages of the guide mechanism that uses a lubricating medium as described above can be eliminated, and four electromagnets are arranged symmetrically on the upper and lower surfaces of the movable body 1, that is, the surfaces in the direction of gravity, increasing the bearing rigidity. Even if a disturbance acts in a direction that is restrained in a non-contact manner by the attractive force of the electromagnet, it is possible to suppress fluctuations in the gap with the guide 2 to a small value.

However, such a magnetic levitation guide mechanism has a large number of electromagnets 3, 4, 5, etc., and has four reference guide surfaces: top, bottom, left and right, and each needs to be finished with high precision separately, resulting in increased costs. There was still room for improvement.

Therefore, the present invention simplifies the structure by realizing straight-line guidance for moving straight in one direction and restraining the remaining 5 degrees of freedom in a non-contact manner by magnetic force using the minimum number of magnets, 6. This mechanism was designed to provide a magnetic levitation guide mechanism that can be manufactured at low cost, reliably supports a movable body in a non-contact manner, and can guide the movable body stably. It has a pair of reference shafts, and a total of six branch parts on both sides, and a minimum of two and a maximum of four branch parts are provided on the side of one reference shaft, and these branch parts are connected to one reference shaft. The remaining number of branch parts are provided on the other side, and these branch parts are arranged between the pair of reference shafts so that they sandwich the other reference shaft and face each other from both sides. An electromagnet fixing body is arranged so as to be relatively movable in the axial direction of the reference shaft, and at each tip of this electromagnet fixing body,
six electromagnets each arranged to face a reference axis corresponding to the tip; and six electromagnets arranged independently of each other on both sides of the electromagnet fixing body so as to face each reference axis from the side. The electromagnets are arranged in such a way that they are oriented in the same direction, and are equipped with a total of five displacement detectors for detecting gaps between the electromagnet fixing body and each reference axis, and are arranged on both sides of each reference axis. When viewed from the axial direction of the pair of reference shafts, the magnetic attraction forces intersect with each other and act on the reference shafts so as to attract the corresponding reference shafts to each other, and the coil current of the electromagnet is used to detect the displacement. The pair of reference shafts and the electromagnet fixing body are kept in a non-contact state by controlling them using signals from the device.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 2 shows the first part of the magnetic levitation guide mechanism according to the present invention.
A perspective view showing the embodiment, FIG. 3 is a front view of the same mechanism,
FIG. 4 is a right side view of the mechanism. In these figures, reference axes 20 and 21 are a pair of reference axes having the same cross-sectional shape and each formed into an isosceles triangle or an equilateral triangle, and these reference axes 20 and 21 are parallel to each other with a certain gap in the vertical direction. It is arranged in a fixed body and constitutes a fixed body. The upper reference shaft 20 is arranged upside down so as to face the lower reference shaft 21.

An electromagnet fixing body 22 constituting a movable body is disposed between the pair of reference shafts 20, 21 so as to maintain a non-contact state with the reference shafts 20, 21 by the magnetic attraction force of the electromagnet, which will be described later. This electromagnet fixing body 22 is
It includes three electromagnetic members 24A, 24B, 24C and a pair of left and right coupling members 25A, 25B that integrally couple these electromagnetic members 24A, 24B, 24C, and each electromagnet member 24A, 24B, 24C has a diameter of about V. Yoke 124a, 1 formed into a letter shape
24b, 124c, and these yokes 124a, 12
Excitation coil 26a is installed at both ends of 4b and 124c.
A pair of electromagnets 26 formed by winding ~31a
, 27, 28, 29, 30, and 31, respectively. And each electromagnetic member 24A, 2
4B, 24C are yokes 124a, 124b, 124
The two electromagnet members 24 in the front and rear are overlapped in the moving direction of the electromagnet fixing body 22, that is, in the axial direction (Z direction) of the reference shafts 20 and 21 at the bent part of c.
A, 24C are arranged with the bent portions of the yokes 124a, 124c facing down so as to sandwich the upper reference shafts 20, 21 from below, and the central electromagnet member 24B is arranged so as to sandwich the lower reference shaft 21 from above. The bent portion of the iron 124b is placed upward. In addition, in FIGS. 2 and 4, the connecting member 25 is shown in order to make the configuration easier to understand.
A and 25B are omitted from the illustration.

The pair of electromagnets 26 and 27 and 28 and 29 provided in the electromagnet members 24A and 24C have their magnetic pole faces facing each slope of the reference shaft 20, and the electromagnet members 2
A pair of electromagnets 30 and 31 provided in 4B
has its magnetic pole face facing each slope of the reference shaft 21. For this reason, three electromagnets 27, 29, 31 are placed on the left and right sides when viewed from the front of the reference shafts 20, 21.
, and 26, 28, and 30 are arranged, and the directions 37 and 38 of the magnetic attraction force between the left and right electromagnets 26 and 27, 28 and 29, and 30 and 31 that form a pair intersect at a constant angle as shown in FIG. are doing.

The electromagnet fixing body 22 includes five displacement detectors 32 to 3 in addition to the six electromagnets 26 to 31 described above.
6 are arranged almost symmetrically with the arrangement of these electromagnets 26-31. These five displacement detectors 32
36 are each formed in a cylindrical shape, one displacement detector 32 is placed in the space between the electromagnets 26 and 28, and the remaining four displacement detectors 33 to 36 are placed on both sides of the electromagnets 30 and 31. ing. The coil currents supplied to the excitation coils 26a to 31a of the electromagnets 26 to 31 are controlled by the signals from the displacement detectors 32 to 36 by a control device (not shown), thereby controlling the excitation coils 26a to 31a of the electromagnets 26 to 31. Reference axis 2
0 and 21 is kept constant, and the electromagnet fixing body 22 is supported without contacting the reference shafts 20 and 21.

That is, in the present invention, as shown in FIG. 2, the degrees of freedom of movement in two directions x and y, excluding the moving direction (Z direction) of the electromagnet fixing body 22, and rotation in three directions θ, φ, and Ψ are provided. The function of stably restraining in a non-contact state is achieved using a minimum of six electromagnets 26 to 31. Moreover, since the magnetic levitation guide mechanism of the present invention applies magnetic attraction force both up and down in the direction of gravity, it is possible to support the electromagnet fixing body 22 in a non-contact state regardless of gravity, and therefore, it is possible to support the electromagnet fixing body 22 in a non-contact state regardless of gravity. The non-contact support function will not be impaired in any way even if external force is applied.

Figures 5 to 8 show a second embodiment of the present invention, with Figure 5 being a perspective view, Figure 6 being a front view, Figure 7 being a left side view, and Figure 8 being a right side view. be. In this embodiment, two electromagnetic members 24A and 24C, front and rear, are used.
are placed on the right side of the reference shafts 20, 21, and the central electromagnet member 24B is placed on the left side of the reference shafts 20, 21. Therefore, in this example, 4
Electromagnets 26, 27, 29, 30 and one displacement detector 32 are arranged on the right side of the reference shafts 20, 21, and the remaining two electromagnets 28, 31 and four displacement detectors 33 to 36 are placed as a reference. It is arranged on the left side of the shafts 20 and 21. Note that the directions 37 and 38 of the magnetic attraction forces of the electromagnets 26, 27 and 28 facing each other with the reference shaft 20 in between and the electromagnets 29, 30 and 31 facing each other with the reference shaft 21 in between are constant as in the second embodiment. intersect at an angle. In this case, the electromagnets 26, 29 and the yoke 124a form a pair to constitute an electromagnet member 24A, and similarly the electromagnets 28, 3
1 and the yoke 124b to form an electromagnet member 24B,
The electromagnets 27 and 30 and the yoke 124c each constitute an electromagnet member 24C.

It will be obvious that even in such a configuration, the electromagnet fixing body 22 can be supported in a non-contact manner.

9 and 10 are a perspective view and a front view showing a third embodiment of the present invention. In this embodiment, the pair of reference shafts 20, 21 have different cross-sectional shapes, and the electromagnetic members 24A, 24B, 24C are tilted so that their upper and lower ends are positioned on the left and right sides with respect to the central axis 40 of the reference shafts 20, 21, respectively. It is something.
For this reason, each electromagnetic member 24A, 24B, 24C
The pairs of electromagnets 26 and 30, 28 and 29, and 27 and 31 are located on opposite sides of the reference shafts 20 and 21, respectively, so that three electromagnets 28, 30, 31 are placed on the left and right sides of the central axis 40, respectively. and 2
6, 27, and 29 are arranged, and their magnetic poles face the slopes of the respective reference axes 20, 21. In this case, as shown in FIG. 10, it is necessary to arrange the electromagnet 26 so that the direction 37 of the magnetic attraction force facing the reference axis 20 is not parallel to the direction 41 of the magnetic attraction force of the electromagnet 30 facing the reference axis 21. Therefore, the slope facing the electromagnet 26 of the reference shaft 20 and the reference shaft 21
The electromagnet 30 must not be parallel to the opposing slope.

That is, three electromagnets are arranged facing each other on the reference shafts 20 and 21, and three electromagnets are arranged on each of the left and right sides of the reference shafts 20 and 21.
In the embodiment, a stable floating state cannot be obtained unless the configuration has the above-mentioned restrictions, and this can be theoretically proven. Note that in the first and second embodiments, the electromagnets 26 to 31 are arranged differently, so they are not subject to such restrictions.

FIG. 11 is an enlarged front view of main parts showing a fourth embodiment of the present invention. In this embodiment, a reference shaft 20 is formed by overlapping a plurality of silicon steel plates in the moving direction of the electromagnet fixing body 22, and the surface portion of the reference shaft 20 that is opposed to the inductance type displacement detector 32, that is, A long plate-shaped electrical conductor 42 extending over the entire length of the reference shaft 20 is embedded in a portion of the U-shaped electromagnet 26 facing between the magnetic poles of the yoke.

The electromagnet fixed body 22 as a movable body can be moved by a driving means such as a linear motor or a voice coil motor (not shown).
If is a good conductor such as ordinary iron, then the electromagnet 26
Because the magnetic flux passes through it, when it moves relatively, an eddy current is generated on the surface of the reference shaft 20, and due to this and the magnetic flux, the driving force in the moving direction of the electromagnet fixing body 22 is proportional to the speed. Braking force is generated, which becomes an obstacle to high-speed driving and reduces performance. Therefore, as described above, by making the reference shaft 20 constituting the guide surface of the electromagnet fixing body 22 a laminate of silicon steel plates or a soft magnetic ferrite material, eddy currents can be eliminated and the above-mentioned performance deterioration can be prevented. However, in this case, a relatively inexpensive and easily available inductance variable type displacement detector cannot be used to detect displacement for the magnetic levitation function.To solve this problem, the electrically conductive material 42 is It is provided on the reference axis 20.

FIG. 12 and FIG. 13 are a perspective view and a front view showing a fifth embodiment of the present invention. This embodiment uses a pair of reference shafts 43 and 44 made of cylindrical bodies. The reference shafts 43 and 44 made of cylindrical bodies have the advantage that the diameter and flatness of the generating line can be machined relatively easily and with high precision, and that the distance between the shafts can be accurately determined and assembled.
This structure can be said to be suitable for obtaining a highly accurate magnetic levitation guide mechanism. Note that the electromagnets 26 to 31 and the displacement detectors 32 to 36 are arranged in the same manner as in the first embodiment shown in FIGS. 2 to 4, so a description thereof will be omitted.

FIG. 14 is a perspective view showing a sixth embodiment of the present invention. In this embodiment, a pair of reference shafts 4 each having a cylindrical shape are used.
3 and 44, and electromagnets 26 to 31 and displacement detectors 32 to 36 are arranged similarly to the second embodiment shown in FIGS. 5 to 8.

FIG. 15 is a perspective view showing a seventh embodiment of the present invention, in which a pair of cylindrical reference shafts 43 and 44 are shown.
using the electromagnets 26 to 31 and the displacement detectors 32 to 31 as in the third embodiment shown in FIGS.
36 are arranged.

In addition, in all embodiments of the present invention, the pair of reference shafts 20 and 21 are fixed bodies, and the electromagnet 2
6 to 31 and displacement detectors 32 to 36 is a movable body. Of course, it is possible to obtain exactly the same function by using the electromagnet fixing body 22 as a movable body and using the electromagnet fixed body 22 as a fixed body. In addition, when determining this, by using a relatively complex structure as the fixed body, it is advantageous to be able to reduce weight and remove restrictions on wiring, etc.

As explained above, the magnetic levitation guide mechanism according to the present invention has six electromagnets and a displacement detector that carry the levitation mechanism.
Since it is possible to reduce the number of fixed parts to a minimum of 5 pieces, it is useful for reducing the number of parts and electromagnet current control devices, shortening manufacturing and assembly time, and it is possible to use highly accurate parts shapes, making it stable. Excellent in sex,
A magnetic levitation guide mechanism with high performance can be provided.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing a conventional example of a magnetic levitation guide mechanism, Fig. 2 is a perspective view showing a first embodiment of the magnetic levitation guide mechanism according to the present invention, Fig. 3 is a front view thereof, and Fig. 4 5 to 8 are perspective views, front views, left side views, and right side views showing the second embodiment of the present invention, and FIGS. 9 and 10 are the third embodiment of the present invention. A perspective view and a front view showing an example, 1st
FIG. 1 is an enlarged front view of main parts showing a fourth embodiment of the present invention, FIGS. 12 and 13 are perspective views and front views showing a fifth embodiment of the present invention, and FIG. 14 is a sixth embodiment of the present invention. FIG. 15 is a perspective view showing a seventh embodiment of the present invention. 20, 21... Reference axis, 22... Electromagnet fixing body, 24A to 24C... Electromagnet member, 25A, 2
5B...Coupling member, 26-31...Electromagnet, 26
a~31a... Excitation coil, 32~36... Displacement detector, 37, 38, 41... Direction of magnetic attraction force, 42... Good electrical conductor, 43, 44... Reference axis made of cylindrical body, 124a~ 124c...Yoke.

Claims (1)

[Scope of Claims] 1 A pair of reference shafts arranged in parallel, and a total of six branch parts on both sides, with a minimum of two and a maximum of four branch parts on the side of one reference axis. is established,
These branch parts sandwich one reference axis and face each other from both sides, and the remaining number of branch parts are provided on the other side, and these branch parts sandwich the other reference axis and face each other from both sides. An electromagnet fixing body is disposed between a pair of reference axes so as to be relatively movable in the axial direction of both reference axes, and an electromagnet fixing body is provided at each tip of the electromagnet fixing body to face the reference axis corresponding to the tip. Six electromagnets each arranged as follows,
They are arranged on both sides of the electromagnet fixing body so as to face each reference axis from the side, and are arranged so that they are oriented independently from each other, and detect the gap between the electromagnet fixing body and each reference axis. When viewed from the axial direction of the pair of reference axes, the direction of the magnetic attraction force of the electromagnets, which are arranged on both sides of each reference axis, is as follows:
The pair of reference shafts and the electromagnet fixing body are brought into a non-contact state by acting on the reference axes so as to intersect with each other and attracting the corresponding reference axes to each other, and by controlling the coil current of the electromagnet by the signal of the displacement detector. A magnetic levitation guide mechanism that maintains 2. Claim 1, characterized in that the reference shaft is composed of a laminate of silicon steel plates, and a good electrical conductor is provided along the entire length of the reference shaft in the longitudinal direction on the surface portion corresponding to the displacement detector. Magnetic levitation guide mechanism as described. 3. The magnetic levitation guide mechanism according to claim 1 or 2, wherein the reference axis is a cylindrical body.