JPH0956146A - Magnet worm gear and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic worm gear which can be made small and light so as to be suitable for a micro-machine and also provide a method for manufacturing gear by using a thin-film formation technology and a fine processing technology which are used in semiconductor processes, etc. SOLUTION: A magnetic worm gear is made by a combination of a worm 1 which has spiral magnetic teeth on its circumferential face and a worm wheel 2 which magnetically gears in with the worm 1. In the magnetic worm gear, motive force is transmitted by magnetic force which works between the magnetic teeth. The spiral magnetic teeth which are formed on the circumferential face of the worm and magnetic teeth which are formed on the circumferential face of the worm wheel in compliance with a magnetic tooth pitch of the worm are made of thin-film magnets 3, 4 which are so magnetized that N poles and S poles may be arranged alternately. The thin-film magnets 3, 4 are made by winding a flexible substrate on which a magnet material-made magnetic thin film is formed around a base body of the worm and the worm wheel and then magnetizing the magnetic thin film into N poles and S poles in accordance with a pattern of the magnetic teeth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes a magnetic force acting between magnetic teeth by combining a worm having spiral magnetic teeth formed on its peripheral surface with a worm wheel that magnetically meshes with the worm. The present invention relates to a magnetic worm gear that transmits power from a worm to a worm wheel with a large reduction ratio, and particularly to an ultra-small size magnetic worm gear applied to a micromachine, and a manufacturing method thereof.

[0002]

2. Description of the Related Art The magnetic worm gear mentioned above has a structure shown in FIG.
ONS ON MAGNETICS, VOL. 29, N
O6, NOVENVER 1993, p2923-29
25, "Design a-nd Character
istis of A New Magneti-c
Worm Gear Using Parmanen
t Magnet ”.

In FIG. 9, 1 is a permanent magnet (for example, SmCo).
Barrel-shaped worm made of ₅ bulk permanent magnets) 1a is the drive shaft of the worm 1, and the magnetic teeth of the permanent magnets magnetized in the N pole and S pole in a spiral shape on the yoke peripheral surface of the worm 1. They are arranged alternately. Further, 2 is a dish-shaped worm wheel made of a permanent magnet magnetically meshed with the worm 1 with a gap therebetween, 2a is a driven shaft provided on the worm wheel, and includes a peripheral surface of the worm 1. As described above, the magnetic teeth of the permanent magnets magnetized to the N pole and the S pole are arranged alternately on the inner peripheral surface of the concave ring formed on the worm wheel 2 according to the pitch of the magnetic pole teeth of the worm 1. There is.

With such a structure, when the worm 1 is rotationally driven, the worm wheel 2 is non-contactly rotated by the magnetic force acting between the magnetic teeth of the worm 1 and the magnetic teeth of the worm wheel 2 to transmit power. It The reduction ratio in that case is determined by the ratio between the number of magnetic teeth of the worm 1 and the number of teeth of the worm wheel 2. Since this magnetic worm gear has no mechanical meshing unlike a normal worm gear, it has an advantage that friction resistance between the worm and the worm wheel is zero, and high power transmission efficiency can be obtained.

[0005]

A driving actuator (motor) incorporated in a micromachine is required to be ultra-miniaturized. However, the microminiature actuator has a small power generation, and it is necessary to operate the micromachine with a small power generation. A gear device for power transmission with a large reduction ratio is required in the power transmission path, and it is effective to employ the above-mentioned magnetic worm gear for this gear device.

However, since the conventional magnetic worm gear described above is constructed by using bulk permanent magnets for the magnetic teeth of the worm and worm wheel, it takes a lot of time and effort to manufacture it, resulting in a high cost. In addition, only large worm gears can be manufactured due to the brittleness of the material of the permanent magnets.For example, it is technically almost impossible to manufacture ultra-small worm gears with an outer diameter of mm order to be incorporated in a micromachine. It is impossible.

The present invention has been made in view of the above points, and by utilizing thin film formation and microfabrication technology used in semiconductor processes, etc., a magnetic type which enables ultra miniaturization for power transmission of micromachines and the like. An object of the present invention is to provide a worm gear and a manufacturing method thereof.

[0008]

To achieve the above object, according to the present invention, a combination of a worm having spiral magnetic teeth formed on its circumferential surface and a worm wheel magnetically meshing with the worm is used. In a magnetic worm gear that transmits power by the magnetic force that acts between the magnetic teeth, the magnetic teeth of the worm and worm wheel shall be formed of thin film magnets. The worm and the worm wheel can be appropriately combined.

1) The spiral magnetic teeth arranged on the circumferential surface of the worm are formed by two thin film magnets magnetized by alternately arranging N poles and S poles on the surface. 2) The spiral magnetic teeth arranged on the peripheral surface of the worm are formed by a single thin film magnet arranged on the magnetic yoke by magnetizing either the N pole or the S pole on the surface. 3) The magnetic teeth of the worm wheel are formed by thin film magnets magnetized by alternately arranging N poles and S poles in accordance with the magnetic tooth pitch of the worm.

4) The magnetic teeth of the worm wheel are formed of thin film magnets magnetized to either N pole or S pole according to the magnetic tooth pitch of the worm. The magnetic worm gear having the above structure is manufactured by the following manufacturing method according to the present invention. a) A magnetic thin film of a magnetic material is formed on a flexible substrate, and the flexible substrate is adhered to the base surface of a worm or a worm wheel. In this state, a pattern corresponding to the magnetic teeth of the worm or the worm wheel is formed. At the same time, the magnetic thin film is magnetized.

B) A magnetic thin film of a magnetic core material and a magnetic thin film of a magnet material are formed in this order on a flexible substrate, and the magnetic thin film of the magnet material corresponds to a magnetic tooth of a worm or a worm wheel. The tooth row of the pattern is formed, and the tooth row is magnetized in this state, and then the flexible substrate is attached to the peripheral surfaces of the worm and the worm wheel.

C) A worm or worm wheel substrate itself is used as a magnetic yoke to form a groove portion in a pattern corresponding to magnetic teeth on its peripheral surface, and a magnetic thin film of a magnetic material is formed on the surface of the substrate so as to fill the groove portion. After forming the film and further removing the magnetic thin film deposited on other than the groove, the magnetic thin film filling the groove is magnetized. Also, in a configuration different from that described above, of the worm and the worm wheel, the magnetic teeth of the worm are formed of thin film magnets, and the magnetic teeth of the worm wheel are formed of electromagnets arranged in accordance with the magnetic tooth pitch of the worm. There is also.

As described above, by forming the worm or worm wheel magnetic teeth with the thin film magnet having a thickness of the order of μm manufactured by using the thin film forming technique and the fine processing technique, the bulk permanent magnet is not used. It is possible to reduce the size and weight of a magnetic worm gear to an ultra-compact size with an outer diameter of several mm.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The above-mentioned magnetic worm gear is a combination of a drum-shaped worm and a spur gear-shaped worm wheel as in the case of an ordinary worm gear, or a barrel-shaped worm and a dish-shaped worm as shown in FIG. Thin-film magnets that correspond to the magnetic teeth of the worm and the worm wheel are thin film forming techniques such as vacuum deposition and sputtering methods used in semiconductor processes, and photolithography. It can be formed by using a fine processing technique such as an etching method. Further, the worm and the worm wheel can be implemented by appropriately combining the structures described in each of the following embodiments. In the drawings of the following respective embodiments, the same members corresponding to FIG. 9 are designated by the same reference numerals.

[Embodiment 1] FIGS. 1A and 1B show an embodiment in which a drum-shaped worm 1 and a spur gear-shaped worm wheel 2 are basically combined. Here, the worm 1, The magnetic teeth of the worm wheel 2 are composed of thin film magnets 3 and 4 in which N poles and S poles are alternately arranged. That is, the thin-film magnet 3 wound around and attached to the peripheral surface of the drum-shaped base (yoke) 1b of the worm 1 has a two-row thin-film magnet whose surface is magnetized as N pole and S pole at a predetermined pitch. Are spirally patterned. On the other hand, the thin film magnet 4 wound around the peripheral surface of the disk-shaped base body 2b of the worm wheel 2 is
It is magnetized in a pattern such that N poles and S poles are alternately arranged according to the magnetic tooth pitch of the worm 1.

The thin film magnets 3 and 4 are manufactured by the following manufacturing method. That is, FIGS. 6A to 6D are explanatory views showing a method of manufacturing the worm 1, and first, FIG.
A worm substrate 1b having a diameter of several mm made of metal or non-metal shown in (a) and a flexible substrate 3a having a thickness of several μm as shown in FIG.
A magnetic thin film 3b having a thickness of several .mu.m to several tens of .mu.m is formed by using a thin film forming technique such as a vacuum deposition method or a sputtering method with an NdFeB type or SmCo type magnetic material. The worm body 1b is shown as a cylindrical shape, but actually it has a drum shape as described in FIG. Next, as shown in FIG. 6 (c), the flexible substrate 3a is wound around the peripheral surface of the worm substrate 1b with the magnetic thin film 3b facing the surface, and is adhered. ), The thin film magnet 3 of the worm 1 is magnetized so that N poles and S poles are alternately arranged in a spiral shape along the axial direction.
Is configured.

Also for the worm wheel 2, a flexible substrate having a magnetic thin film formed thereon is wound around the peripheral surface of a disk-shaped substrate 2b having a diameter of about 10 mm in the same manner as in FIG. It is assumed that the thin film magnet 4 is formed by alternately magnetizing N poles and S poles in a pattern corresponding to the magnetic teeth of the worm wheel 2. In the magnetic worm gear of FIG. 1 manufactured as described above, between the thin film magnet 3 of the worm 1 and the thin film magnet 4 of the worm wheel 2 facing the non-contact type with a small gap therebetween. Has a magnetic force that attracts the N and S poles. Therefore, when the worm 1 is rotationally driven around the drive shaft 1a,
Similar to the magnetic worm gear of FIG. 9, the worm wheel 2 rotates around the driven shaft 2a in a decelerated manner following the rotation of the worm 1, and power is transmitted from the worm 1 to the worm wheel 2.

[Embodiment 2] FIGS. 2 (a) and 2 (b) show an embodiment in which a barrel-shaped worm 1 and a dish-shaped worm wheel 2 are combined, and a spiral shape formed on the peripheral surface of the worm 1 is used. The magnetic teeth and the magnetic teeth formed on the concave ring-shaped peripheral surface of the worm wheel 2 are formed of thin film magnets 3 and 4 in which N poles and S poles are alternately arranged, as in the first embodiment, and the thin film magnets. The magnets 3 and 4 are magnetized so that the N poles and the S poles are alternately arranged according to the patterns corresponding to the magnetic teeth of the worm 1 and the worm wheel 2, respectively. The worm 1 in this embodiment can be manufactured by using the manufacturing method of FIG. 8 described in the first embodiment.

[Embodiment 3] Next, FIG. 3 shows an embodiment of the present invention applied to the worm 1. In this embodiment, the base body 1b of the worm 1 is made of a magnetic core material such as iron or permalloy, and a single spiral groove is formed on the peripheral surface thereof at a predetermined pitch so as to fill the spiral groove. A thin film magnet 3 whose surface is magnetized to have N pole (or S pole) is laid to form worm spiral magnetic teeth.

According to this structure, the thin film magnets 3 which are spirally formed and magnetized have the opposite polarities appearing on the front surface and the back surface (if the front surface is the N pole, the back surface is the S pole). Further, the worm base 1b functions as a magnetic yoke, whereby the pitch of the thin film magnets 3 has a polarity opposite to the surface polarity of the thin film magnets, that is, if the surface of the thin film magnets 3 has an N pole, an S pole between the pitches. Appears and functions in the same manner as the worms of Examples 1 and 2. Therefore, the worm 1 of FIG. 3 can be replaced with the worm of FIG. Although the shapes are different, the magnetic teeth of the hourglass-shaped worm in FIG. 2 can be formed by a single spiral thin film magnet as in FIG.

Next, a method for manufacturing the worm 1 shown in FIG. 3 will be described with reference to FIGS. First, FIG.
As shown in (a), a spiral groove 1c is formed on the peripheral surface of a worm substrate 1b made of a magnetic core material by an etching method.
Next, a magnetic thin film 3b is formed by depositing a magnetic material of NdFeB type or SmCo type, which is a magnetic material, on the peripheral surface of the base body 1b by vacuum deposition or sputtering so as to fill the spiral groove 1c. (FIG. 7B), and the base 1 is left by leaving the portion where the spiral groove 1c is filled by the etching method.
The unnecessary magnetic thin film deposited on the surface of b is removed. This state is shown in FIG. After that, the spiral groove 1
The thin film magnet 3 shown in FIG. 7 (d) is formed by performing pulse magnetization along the surface of the magnetic thin film 3b in which c is filled so that the surface becomes the N pole (the back surface is the S pole). It is needless to say that the magnetic thin film 3b may be magnetized so that the front surface has the S pole and the back surface has the N pole.

Another manufacturing method for manufacturing the worm 1 equivalent to that shown in FIG. 3 will be described with reference to FIGS. That is, in this manufacturing method, as shown in FIG. 8A, first, a thin film forming technique such as a vacuum deposition method or a sputtering method is used on the flexible substrate 3a to form iron, silicon steel, permalloy, etc. to be a magnetic yoke. The magnetic thin film 3c of the magnetic core material is formed, and the magnetic thin film 3b of NdFeB type or SmCo type which is the magnetic material is further formed on the magnetic thin film 3c. Next, a tooth row 3d (FIG. 8B) having a pattern corresponding to the spiral magnetic tooth of the worm 1 is formed on the magnetic thin film 3b by the photolithography method, and then the tooth row is formed by the pulse magnetization method. The surface of 3d is magnetized so that it has an N pole (a back surface is an S pole). In this case, the tooth row 3d is shown in FIG.
The pattern is developed as shown in (c), the flexible substrate 3a is rolled, and both ends of the flexible substrate 3a are joined together.
So that they form a spiral. And the worm base 1
The flexible substrate 3a of the thin-film magnet 3 described above on the peripheral surface of b.
By winding so that the tooth row 3d faces outward,
As shown in FIG. 8 (d), the worm 1 is provided with a spiral thin film magnet whose surface is magnetized to the N pole. The back surface side (S pole) of the spiral tooth row 3d whose surface is magnetized to N pole
The magnetic thin film 3c of the magnetic core material layered on the flexible substrate so as to be in contact with and functions as a magnetic yoke, and the S pole appears between the pitches of the tooth row 3d.

In the manufacturing method of FIG. 8, two spiral tooth rows are formed on the flexible substrate, and one of them is N-shaped.
By magnetizing the S pole to the pole and the other to the S pole, the N pole and the S pole are formed on the peripheral surface of the base body 1b as in the worm 1 of FIG.
It is also possible to form spiral magnetic teeth with alternating poles. [Fourth Embodiment] FIG. 4 shows an application example of the worm wheel 2 corresponding to the worm of the third embodiment. In this embodiment, the base body 2b of the worm wheel 2 is made of a magnetic core material like the worm 1 of FIG. 3, and is arranged on the peripheral surface in a comb-like shape with a pitch aligned with the magnetic tooth row of the worm. A groove is formed, and a thin film magnet 4 whose surface is magnetized to have an N pole is formed so as to fill the groove to form a spur gear-shaped worm wheel. Further, the thin film magnet 4 in this embodiment can be manufactured by applying the manufacturing method of FIG. 7 or 8 described as the manufacturing method of the above-described third embodiment.

According to this structure, like the worm 1 of FIG. 3, the thin-film magnet 4 has opposite polarities appearing on the front surface and the back surface (if the front surface is the N pole, the back surface is the S pole), and the worm wheel. The base body 2b of 1 functions as a magnetic yoke, and as a result, a polarity opposite to the surface polarity of the thin-film magnet 4 between the pitches of the thin-film magnet 4, that is, if the surface of the thin-film magnet 4 is N-pole, an S-pole appears between the pitches. Functions the same as the warm wheel of the first embodiment. Therefore, the worm wheel 2 of FIG. 4 can be replaced with the worm wheel of FIG. 1 or can be implemented in combination with the worm wheel 1 of FIG.

[Fifth Embodiment] FIG. 5 shows still another embodiment of the worm wheel 2 having a spur gear shape.
In this embodiment, the base body 2b of the worm wheel 2 is made of a magnetic core material, and magnetic pole teeth 2c arranged in a comb shape corresponding to the magnetic tooth pitch of the worm are formed on the peripheral surface by an etching method or the like. A thin film coil 2d is wound around the magnetic pole teeth 2c to form an electromagnet 2e. The thin-film coil 2d is connected in series by alternately changing the winding direction, and the N-pole and the S-pole are arranged alternately while the magnetic pole tooth 2c is excited by passing a current through the coil 2d.

The spur gear-shaped worm wheel 2 provided with this electromagnet can be combined with the worm 1 shown in FIG. 1 or FIG. 3 to form a magnetic worm gear. The dish-shaped worm wheel 2 shown in FIG.
Also in this case, the magnetic teeth formed on the concave ring-shaped peripheral surface can be configured by an electromagnet that is a combination of magnetic pole teeth and a thin film coil.

Moreover, according to the worm wheel having the above-mentioned structure, the power transmission ability between the worm and the worm can be adjusted by changing the exciting current of the electromagnet 2e, that is, the magnetic force generated by the electromagnet. Further, by controlling ON / OFF of the exciting current of the coil, the worm gear can be provided with a function as a clutch. The thin-film coil 2d is connected to the magnetic pole teeth 2
If each c is controlled independently and energization is controlled individually,
Energization control is also possible in which only the magnetic pole teeth that are close to the worm are excited and the other magnetic pole teeth are de-excited.

[0028]

As described above, according to the present invention, in the magnetic worm gear, by forming the magnetic teeth of the worm or the worm wheel by using the thin film magnet, a worm gear device having a large reduction ratio can be obtained. Miniaturization and weight reduction can be realized. By using thin film forming technology such as vapor deposition and sputtering method, and microfabrication technology such as photolithography and etching method for manufacturing, ultra-compact magnetic worm gear on the order of mm for micromachines. Can be produced.

[Brief description of drawings]

1A and 1B are configuration diagrams of a magnetic worm gear according to a first embodiment of the present invention in which a drum-shaped worm and a spur gear-shaped worm wheel are combined, FIG. 1A being a front view and FIG. 1B being a side view. Figure

FIG. 2 is a configuration diagram of a magnetic worm gear corresponding to a second embodiment of the present invention in which a barrel-shaped worm and a dish-shaped worm wheel are combined, (a) is a front view, and (b) is a sectional side. View

FIG. 3 is a configuration diagram of an application example of the present invention related to a worm.

FIG. 4 is a configuration diagram of an application example of the present invention related to a warm wheel.

FIG. 5 is a configuration diagram of a different embodiment of the present invention in which a magnetic tooth row of a worm wheel is formed by an electromagnet.

FIG. 6 is an explanatory view of the method for manufacturing the worm in FIGS. 1 and 2, wherein (a) is an outline drawing of the worm base;
(B) is a cross-sectional view of a member constituting a thin film magnet, (c) is a view showing a state in which the member is wound around a worm substrate,
(D) Outline drawing of the worm completed by magnetizing the magnetic thin film

7A and 7B are explanatory views of the method for manufacturing the worm shown in FIG. 3, in which FIG. 7A is a sectional view of the worm substrate, FIG. 7B is a diagram showing a state in which a magnetic thin film is formed on the worm substrate, and FIG. Is a diagram showing a state in which unnecessary magnetic thin film portions are removed, and (d) is an outline drawing of a worm completed by magnetizing a spiral magnetic thin film.

8A and 8B are explanatory views of a method for manufacturing a worm different from FIG. 7, in which FIG. 8A is a cross-sectional view of a flexible substrate on which a magnetic thin film of a magnetic core material and a magnetic material are formed, and FIG. Sectional view of a state in which a tooth row is patterned on the magnetic thin film of
(C) is a plan development view of the dentition, (d) is an outline view of a worm completed by winding the member around a worm base and magnetizing the dentition

9A and 9B are configuration diagrams of a conventional magnetic worm gear that employs a bulk permanent magnet, in which FIG. 9A is a front view and FIG.
Is a cross-sectional side view

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 worm 1a drive shaft 1b base body 1c spiral groove 2 worm wheel 2a driven shaft 2b base body 2c magnetic pole tooth 2d thin film coil 2e electromagnet 3 worm thin film magnet 3a flexible substrate 3b magnetic thin film (magnet material) 3c magnetic thin film (magnetic core material) 3d tooth Row

Claims (9)

[Claims] 1. A magnetic worm which comprises a combination of a worm having spiral magnetic teeth formed on its peripheral surface and a worm wheel which magnetically meshes with the worm, and which transmits power by a magnetic force acting between the magnetic teeth. In the gear, a magnetic worm gear characterized in that the magnetic teeth of the worm and the worm wheel are formed of thin film magnets. 2. A magnetic worm gear according to claim 1, wherein spiral magnetic teeth arranged on the circumferential surface of the worm are magnetized with N and S poles alternately arranged on the surface. A magnetic worm gear characterized by being formed by. 3. The magnetic worm gear according to claim 1, wherein spiral magnetic teeth arranged on the circumferential surface of the worm are magnetized on the surface by magnetizing either N pole or S pole. A magnetic worm gear characterized in that it is formed of an array of thin film magnets. 4. The magnetic worm gear according to claim 1, wherein the magnetic teeth of the worm wheel are formed by thin film magnets magnetized by alternately arranging N poles and S poles according to the magnetic tooth pitch of the worm. Magnetic worm gear characterized by. 5. The magnetic worm gear according to claim 1, wherein the magnetic teeth of the worm wheel are formed by thin film magnets magnetized to either N pole or S pole according to the magnetic tooth pitch of the worm. Magnetic worm gear characterized by. 6. A magnetic thin film of a magnetic material is formed on a flexible substrate, and the flexible substrate is adhered to a base surface of a worm or a worm wheel. In this state, it corresponds to the magnetic teeth of the worm or the worm wheel. The method of manufacturing a magnetic worm gear according to claim 1, wherein the magnetic thin film is magnetized in accordance with the pattern. 7. A magnetic thin film of a magnetic core material to be a yoke and a magnetic thin film of a magnet material are sequentially formed on a flexible substrate,
Further, a worm or a tooth row corresponding to the magnetic tooth pattern of the worm wheel is formed on the magnetic thin film of the magnetic material, and the tooth row is magnetized in this state, and then the flexible substrate is warmed, worm The method for manufacturing a magnetic worm gear according to claim 1, wherein the wheel is attached to the peripheral surface of the base body. 8. A worm or worm wheel substrate itself is used as a magnetic yoke to form groove portions in a pattern corresponding to magnetic teeth on its peripheral surface, and a magnetic thin film of a magnetic material is formed on the surface of the substrate so as to fill the groove portions. 2. The method for manufacturing a magnetic worm gear according to claim 1, wherein the magnetic thin film filling the groove is magnetized after forming the film and further removing the magnetic thin film deposited on other than the groove. 9. A magnetic worm comprising a combination of a worm having spiral magnetic teeth formed on its circumferential surface and a worm wheel magnetically meshing with the worm, and transmitting power by a magnetic force acting between the magnetic teeth. In the gear, a magnetic worm gear characterized in that the magnetic teeth of the worm are formed of thin film magnets, and the magnetic teeth of the worm wheel are formed of electromagnets arranged according to the magnetic tooth pitch of the worm.