JPH09303515A - Magnetic screw device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic screw device which has a large thrust in the axial direction, and can improve the positioning accuracy. SOLUTION: This magnetic screw device consists of a male screw member 1 formed cyrindrically of a permanent magnet material, and composed by providing spiral N and S poles on its outer peripheral surface in the axial direction alternately; and a female screw member 2 formed of a permanent magnet material, having a cylindrical inner peripheral surface where the male screw member 1 can be inserted, and composed by providing spiral N and S poles with the same pitch as those provided on the outer peripehral surface of the male screw member 1, on its inner peripheral surface in the axial direction alternately; and while the male screw member 1 and the female screw member 2 are combined in order to make their outer peripheral surface and inner peripheral surface coaxial, both members are formed rotatable relatively, and movable in the axial direction relatively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a male screw member formed in a cylindrical shape and provided with a spiral magnetic pole on its outer peripheral surface, and a spiral magnetic pole on a cylindrical inner peripheral surface into which this male screw member can be inserted. The present invention relates to a magnetic screw device which is magnetically combined with a female screw member provided with.

[0002]

2. Description of the Related Art A screw generally comprises a male rod-shaped screw and a female screw having a hole adapted to the male screw. The outer circumferential surface of the male screw and the inner circumferential surface of the female screw are formed with corresponding spiral grooves. There is. The male screw can be held by the female screw by screwing the male screw into the hole of the female screw and contacting the sides of the groove with each other.

Such screws as mechanical elements are widely used not only for fastening, fixing and adjusting the positions of the constituent members, but also for transmitting power and transferring articles. In addition to directly screwing male and female screws, a ball screw with a steel ball in the groove is also used for the purpose of reducing friction loss due to direct contact, improving power transmission efficiency. Have contributed.

[0004]

However, in the conventional screw, since the side surfaces of the groove are in direct contact with each other or the side surfaces of the groove are in direct contact with the balls, friction loss naturally occurs. In order to reduce this friction, it is customary to supply lubricating oil, grease, etc. to the contact portion. Then, it is periodically disassembled to remove fine powder generated by friction, dust that has been mixed in, and replacement of lubricating oil and the like, so that the male screw and the female screw can be screwed smoothly.

On the other hand, recent semiconductor manufacturing equipment, electronics-related equipment, etc. are operated in a clean room free from dust, and therefore, even for a screw as a power transmission means, means for suppressing generation of fine powder due to wear as much as possible is required. It is devised from various directions. However, the conventional screw has a problem in that it is not possible to eliminate environmental pollution due to generation of fine powder, scattering of lubricating oil, etc., because it is a screwing mode involving direct mechanical contact.

A magnetic screw has been proposed as a means for solving the above problems and keeping the environment clean (see, for example, Japanese Unexamined Patent Publication No. 6-204031). This magnetic screw has a round bar-shaped insertion portion, a male screw member having a magnetic pole extending spirally along the axis on the outer peripheral surface of this insertion portion, and a hole having an inner diameter through which this male screw member can be inserted. And a female screw member having a magnetic pole formed on its inner peripheral surface capable of forming a magnetic field with the magnetic pole formed on the outer peripheral surface of the male screw member. .

With the above structure, the male screw member and the female screw member are engaged in a non-contact state, so that the screw members are not damaged or worn, the environment can be kept clean, and an abnormal load is applied. It is said that there is an effect that damage to the screw member can be avoided even when applied.

However, in the above magnetic screw, the female screw member is provided with only one pair of permanent magnets, and the axial length of the female screw member is formed on the male screw member. Since the helical magnetic poles are formed to have substantially the same size as one pitch, the thrust force in the axial direction is small. For example, when a female screw member is incorporated in a table and used as a device for moving an article, There is a problem that the loading weight on the table is limited. There are also problems such as insufficient positioning accuracy and increased manufacturing costs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic screw device which solves the above problems existing in the prior art, has a large axial thrust, and can improve the positioning accuracy.

[0010]

In order to solve the above problems, according to the present invention, a cylindrical NS magnetic pole is formed by a permanent magnet member in a cylindrical shape, and spiral NS magnetic poles are alternately provided on the outer peripheral surface in the axial direction. And a cylindrical inner peripheral surface formed of a permanent magnet material, through which the male screw member can be inserted, and the inner peripheral surface of which has the same pitch as that provided on the outer peripheral surface of the male screw member. And a female screw member in which NS magnetic poles are alternately provided in the axial direction. The male screw member and the female screw member are combined so that their outer peripheral surface and inner peripheral surface are coaxial, and both are relatively rotatable and axially relative to each other. We adopted the technical means of making it movable.

In the present invention, a hollow cylindrical spacer made of a non-magnetic material can be provided between the male screw member and the female screw member. Further, in the above invention, at least two pairs of male screw members and female screw members formed so that the advance of the NS magnetic poles with respect to the rotation in the same direction are opposite to each other are arranged such that their axes are parallel to each other. The female screw member can be integrally formed via the holding member.

[0012]

FIG. 1 and FIG. 2 are a partial vertical sectional front view and a principal part lateral sectional view, respectively, showing a first embodiment of the present invention. 1 and 2, 1 is a male screw member, for example, ferrite (MO.nFe ₂ O ₃ , where M is at least one of Ba, Sr, and Pb, n = 5 to 6),
It is formed into a hollow cylindrical shape by a permanent magnet material such as Mn-Al-C system and R-Fe-B system (where R is at least one of rare earth elements such as Nd or Pr), and its outer peripheral surface is formed. Are formed by alternately providing spiral NS magnetic poles in the axial direction.

Next, 2 is a female screw member, which is made of a permanent magnet material similar to that of the male screw member 1 and is formed into, for example, a hollow cylinder having an inner peripheral surface through which the male screw member 1 can be inserted. On the inner peripheral surface of the female screw member 2, a spiral N having the same pitch as that provided on the outer peripheral surface of the male screw member 1 is formed.
S magnetic poles are provided alternately in the axial direction.

As shown in FIG. 1, the male screw member 1
Magnetic poles having different polarities are always formed on the outer peripheral surface and the inner peripheral surface, which are opposite to each other via the axis of the female screw member 2.

If the male screw member 1 and the female screw member 2 formed as described above are combined so that the outer peripheral surface and the inner peripheral surface thereof are coaxial, a pair of male screw member 1 formed on the outer peripheral surface is formed. Magnetic fields are formed between the magnetic poles and the pair of magnetic poles formed on the inner peripheral surface of the female screw member 2. in this case,
Magnetic poles having different polarities are always formed on the outer peripheral surface and the inner peripheral surface, which are opposite to each other with respect to the axis of the male screw member 1 and the female screw member 2, as described above.
The spiral NS magnetic poles formed on the inner and outer peripheral surfaces of 2 have the same pitch.

Therefore, as a result of the magnetic fields having mutually opposite lines of magnetic force and having the same magnetic force, the male screw member 1 is held coaxially with the inner peripheral surface of the female screw member 2. Further, since the inner diameter of the inner peripheral surface of the female screw member 2 is formed to be slightly larger than the outer diameter of the male screw member 1, both screw members 1, 2
The inner and outer peripheral surfaces of are formed in a non-contact state.

Further, since the magnetic poles formed on the inner and outer peripheral surfaces of the screw members 1 and 2 are spirals extending in the same direction along the axis, the screw members 1 and 2 are relatively rotated about the axis. Then, the magnetic field formed between the screw members 1 and 2 moves spirally, so that the screw members 1 and 2 can be relatively moved in the axial direction. Similarly, the relative movement of the two screw members 1 and 2 in the axial direction causes the two screw members 1 and 2 to move.
Relative rotation can be generated in between.

FIG. 3 is a perspective view of an essential part showing a second embodiment of the present invention. In FIG. 3, 1a and 1b are male screw members and 2a and 2b are female screw members, respectively, which are formed similarly to those shown in FIGS. 1 and 2. In this case, those with the subscripts a and b are formed so that the advance of the spiral NS magnetic poles with respect to the rotation in the same direction are opposite to each other, and the axes of the NS magnetic poles are parallel to each other. To do. In FIG. 3, the suffix a is formed into a left-handed spiral, and the suffix b is formed into a right-handed spiral. The female screw members 2a and 2b are integrally connected via the holding member 3.

With the above structure, the male screw members 1a and 1b are provided.
By synchronizing each in the opposite direction and rotating the same,
The holding member 3 including the internal thread members 2a and 2b can be moved in the axial direction of the external thread members 1a and 1b. In this case, since the rotation directions of the male screw members 1a and 1b are opposite to each other, the twisting moment acting on the holding member 3 can be eliminated. If this holding member 3 is used as, for example, an article moving means, it can be used as a moving means that holds a horizontal state and has a large thrust, and the loaded weight can be increased.

FIG. 4 is an explanatory view schematically showing an example of the method of magnetizing the male screw member in the present invention. In FIG. 4, 4
Is a magnetizing yoke, is provided with openings 5a and 5b through which the male screw member 1 can be inserted in the axial direction through a gap, and a magnetizing coil 6 is wound. A magnetizing power source 7 is connected to both ends of the magnetizing coil 6. The thickness of the magnetizing yoke 4 is substantially the same as the axial dimension (inter-pole pitch) between the NS magnetic poles in FIG.

With the above structure, when a current is passed through the magnetizing coil 6, a magnetic field is formed between the openings 5a and 5b, so that the outer peripheral surface of the male screw member 1 interposed between the openings 5a and 5b is formed. A magnetic pole can be formed. In this case, the male screw member 1 is rotated, and the male screw member 1 is moved relative to the magnetizing yoke 4 by a distance twice the pitch between the magnetic poles shown in FIG. Thereby, a spiral NS magnetic pole can be formed on the outer peripheral surface of the male screw member 1.

FIG. 5 is an explanatory view schematically showing an example of the method of magnetizing the female screw member according to the present invention. In FIG. 5, 8
Is a support member, which is formed of, for example, pure iron in a round bar shape, and has two coil members 9 supported on its outer circumference in a spiral pattern having a predetermined pitch. The coil member 9 is formed of a magnetically soft material, for example, pure iron, electromagnetic steel plate, spring steel, into a rectangular cross section, and is wound around the support member 8 via an insulating material. A spiral groove may be provided on the outer peripheral surface of the support member 8 and the coil member 9 may be embedded in the spiral groove. 1
Reference numeral 0 denotes a terminal, which is connected to a magnetizing power source (not shown).

With the above structure, after the female screw member 2 is inserted and positioned, a pulse current of about several thousand amperes is applied to the two coil members 9 to momentarily magnetize the spiral magnetic poles. You can

[0024]

【Example】

(Example 1) A male screw member having an outer diameter of 18 mm, an inner diameter of 10 mm and a length of 500 mm was produced from an isotropic hard ferrite magnet (YBM-3 manufactured by Hitachi Metals), and a spiral shape having an NS magnetic pole pitch of 15 mm was formed on the outer peripheral surface thereof. Formed the magnetic pole. The peak magnetic flux density of these magnetic poles was 950G. On the other hand, the female screw member was formed of the same material as described above to have an outer diameter of 28 mm, an inner diameter of 20 mm, and a length of 50 mm, and a spiral NS magnetic pole having the same pitch as the above was formed on the inner peripheral surface thereof. The above screw members are coaxially combined, and the male screw member has a peripheral speed of 100 mm / sec (106 r.p.
The thrust force against the female screw member when rotated at m.) is approx.
It was 1.6 kgf.

(Embodiment 2) An apparatus of the embodiment shown in FIG. 3 is manufactured by using male screw members and female screw members having the same dimensions as those in the above Embodiment 1, and the male screw members 1a and 1b are rotated in opposite directions in synchronization with each other. As a result, a torsional moment did not act on the holding member 3, and a linear thrust of about 3.2 kgf was obtained in the axial direction of the male screw members 1a and 1b.

(Third Embodiment) In the first and second embodiments, a pipe spacer made of stainless steel having a thickness of 0.5 mm is fitted on the inner peripheral surface of the female screw member to form a male screw member and a female screw member. When both screw members were rotated relative to each other with the gap filled, there was no change in the linear thrust characteristics with respect to the relative movement of the male screw member in the axial direction.

In the above-described embodiments and examples, the spiral N formed on the male screw member and the female screw member.
Although the description is given for the case where the S magnetic pole is two, the number of spirals can be 2n (n is a positive integer of 1 or more).
The spacer filling the gap between the two screw members may be, for example, an O-ring or the like other than the hollow cylindrical member. Further, the one in the second embodiment can be expanded to have three or more pairs of screw members. The male screw member may be formed into a solid round bar shape.

[0028]

Since the present invention has the configuration and operation as described above, the following effects can be obtained. (1) Since the male screw member and the female screw member are capable of relative rotation and axial relative movement in a non-contact state, there is no damage or wear, and there is no environmental pollution due to generation of fine powder, scattering of lubricating oil, etc. It is extremely effective as a transportation means in a clean room. (2) By providing spiral NS magnetic poles having the same pitch between the magnetic poles on the male screw member and the female screw member, all the magnetic poles are magnetically engaged, so that the thrust in the axial direction can be improved. (3) By engaging a plurality of magnetic poles, it is possible to improve the magnetizing accuracy and improve the stopping accuracy to 50 μm or less. (4) Since the female screw member having a small axial dimension can be integrally magnetized, the manufacturing cost can be reduced. (5) By providing a spacer in the gap between both screw members, a partition state can be secured when used in vacuum or in a non-atmospheric fluid.

[Brief description of drawings]

FIG. 1 is a partial vertical sectional front view showing a first embodiment of the present invention.

FIG. 2 is a lateral cross-sectional view of a main part showing the first embodiment of the present invention.

FIG. 3 is a perspective view of an essential part showing a second embodiment of the present invention.

FIG. 4 is an explanatory view schematically showing an example of a method for magnetizing a male screw member in the present invention.

FIG. 5 is an explanatory view schematically showing an example of a method for magnetizing a female screw member according to the present invention.

[Explanation of symbols]

 1, 1a, 1b Male screw member 2, 2a, 2b Female screw member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H01F 41/02 H01F 41/02 G H01L 21/02 H01L 21/02 D

Claims (3)

[Claims] 1. A male screw member formed of a permanent magnet member in a cylindrical shape and having spiral NS magnetic poles alternately provided on its outer peripheral surface in the axial direction, and the male screw member formed of a permanent magnet material, which can be inserted therethrough. A female screw member having a cylindrical inner peripheral surface and axially alternating helical spiral magnetic poles having the same pitch as those provided on the outer peripheral surface of the male screw member on the inner peripheral surface thereof. A magnetic screw device characterized in that a member and a female screw member are combined such that their outer peripheral surface and inner peripheral surface are coaxial with each other, and both are relatively rotatable and relatively movable in the axial direction. 2. The magnetic screw device according to claim 1, wherein a hollow cylindrical spacer made of a nonmagnetic material is provided between the male screw member and the female screw member. 3. At least two pairs of male screw members and female screw members formed so that the advance of the NS magnetic poles with respect to the rotation in the same direction are opposite to each other are arranged such that their axes are parallel to each other. The magnetic screw device according to claim 1, wherein the female screw member is integrally formed via a holding member.