JPH09184556A - Magnetic screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the invasion of dust in a magnetic nut body as well as the damage of a guide ring and others and further facilitate a handling in assembly. SOLUTION: This magnetic screw is provided with a shaft 1 consisting of a magnetic material and a screw shaft 1 on whose outer periphery surface threads 17, 18 and screw grooves 19, 20 are formed and a magnetic nut body 6, fitted on the outer periphery of this screw shaft l at some intervals, in which the magnetic pole is attached spirally in response to the threads 17, 18 of the screw shaft 1 in an inner periphery surface side. A non-magnetic material 21 is built in the screw grooves 19, 20 of the screw shaft 1 and the outer periphery surface of the screw shaft 1 is constituted flatly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic screw used for machine tools and other various devices.

[0002]

2. Description of the Related Art Conventionally, a screw shaft made of a magnetic material and having a screw thread and a screw groove formed on the outer peripheral surface thereof, and a screw shaft which is fitted on the outer peripheral surface of the screw shaft with a gap and is provided on the inner peripheral surface side. A magnetic nut body having magnetic poles spirally magnetized corresponding to the screw thread of the shaft, and by utilizing the magnetic action of the magnetic poles of this magnetic nut body, one of the straight line of the screw shaft and the magnetic nut body Alternatively, various magnetic screws configured to convert a rotational movement into another rotational or linear movement have been proposed.

[0003]

This magnetic screw converts the linear or rotational movement of one of the screw shaft and the magnetic nut body into the rotational or linear movement of the other by the magnetic action of the magnetic nut body. Since it is not necessary to directly contact the screw shaft and the magnetic nut body, it can be used without lubrication, and it is possible to prevent pollution of the environment due to wear, generation of noise, etc.
There are advantages such as improved durability.

However, since the conventional magnetic screw has a screw thread and a screw groove on the outer peripheral surface of the screw shaft, dust adheres to the inside of the screw groove of the screw shaft or the dust passes through the screw groove depending on the operating environment. There is a possibility that the magnetic nut may enter the inside of the magnetic nut body and adhere or be damaged on the inner peripheral side of the magnetic nut body.

In the case of a normal sliding screw or the like, since the nut body slides along the outer peripheral surface of the screw shaft, even if there is an adhered substance on the screw groove, the nut body slides along the screw groove. It is possible to remove the deposits with a nut body when moving, but in the case of a magnetic screw, there is a gap between the outer peripheral surface of the screw shaft and the inner peripheral surface of the magnetic nut body. It is difficult to remove the deposit attached to the groove by the magnetic nut body.

Moreover, when used in an environment where magnetic powder such as iron powder is liable to be generated, if the magnetic powder adheres to the thread groove due to the residual magnetism of the magnetic nut body, the outer periphery of that portion will be the magnetic nut body. There is also a problem that magnetic powder is adsorbed by the magnetic force of the magnetic pole on the inner peripheral surface of the magnetic powder and adheres to the magnetic nut body and the inner peripheral surface when the magnetic powder passes, and the magnetic powder increases the leakage magnetic flux of the magnetic pole.

Further, since the size of the gap between the outer peripheral surface of the screw shaft and the inner peripheral surface of the magnetic nut body directly affects the magnitude of the thrust force of the magnetic screw itself, the gap is generally made minute. Once the dust enters the magnetic nut body, it is difficult to remove the dust, and the dust and other deposits that have accumulated in the magnetic nut body are located between the magnetic nut body and the threads of the screw shaft. Problems such as biting into the area may occur.

Further, in the case where guide rings for holding the screw shaft in a substantially concentric manner with respect to the magnetic nut body and guiding slidably are provided on both sides in the thrust direction of the magnetic nut body, the angle of the screw thread is However, there is a drawback that the inner circumference side of the guide ring is damaged. In particular, if the screw thread of the screw shaft is a square screw structure, the area of the outer peripheral surface of the screw thread facing the magnetic pole on the magnetic nut body side can be increased, and the magnetic flux leakage can be reduced as much as possible. There is a problem that the guide ring is greatly damaged by the corner of the mountain.

Further, since there are threads on the outer periphery of the screw shaft, the worker is injured at the corners of the screw threads or the screw shaft comes into contact with other members even when the magnetic screw is installed in a required portion. Then, there is a problem that other members or the corners of the screw thread are damaged. In view of such conventional problems, the present invention can prevent dust and the like from entering the body of the magnetic nut, prevent damage to the guide ring and the like, and further facilitate handling when assembling. The purpose is to provide.

[0010]

According to a first aspect of the present invention, there is provided a screw shaft made of a magnetic material and having a screw thread and a screw groove formed on the outer peripheral surface thereof, and a gap is provided on the outer periphery of the screw shaft. And a magnetic nut body having a magnetic pole spirally magnetized on the inner peripheral surface side corresponding to the screw thread of the screw shaft, wherein the magnetic screw is non-magnetic in the screw groove of the screw shaft. A material is embedded and the outer peripheral surface of the screw shaft is made smooth.

According to a second aspect of the present invention, in the first aspect of the invention, the screw shafts are held substantially concentrically with the magnetic nut body on both sides in the thrust direction of the magnetic nut body. A guide ring is provided to guide the slide.

According to a third aspect of the present invention, in the invention according to the first or second aspect, sealing means is provided on both sides of the magnetic nut body in a thrust direction to prevent dust from entering the magnetic nut body. It is provided.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, an air sealing means for sealing with air is used as the sealing means.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 4 illustrate a first embodiment of a magnetic screw according to the present invention. As shown in FIG. 1, the magnetic screw is provided with a screw shaft 1, a magnetic cylinder 2 fitted around the outer periphery of the screw shaft 1 with a gap, and on both sides of the magnetic cylinder 2 in the thrust direction. A pair of guide rings 3 and 4 are provided, and a housing 5 that holds the magnetic cylinder 2 and the guide rings 3 and 4 is provided. The magnetic cylinder 2,
The guide nuts 3, 4 and the housing 5 constitute a magnetic nut body 6.

The housing 5 is made of stainless steel or the like in a tubular shape, and a mounting flange 7 is integrally formed on the outer periphery of the housing 5 on one end side in the thrust direction. Inside the housing 5, a cylindrical body fitting portion 8 is formed on the center side in the thrust direction, a female screw hole 9 is formed on one end side of the cylindrical body fitting portion 8, and a partition wall portion is formed on the other end side.
Guide fitting portions 11 are formed concentrically with the tubular body fitting portion 8 via the respective members.

The magnetic cylinder 2 is a cylinder fitting portion 8 of the housing 5.
It is inserted into and removed from the inner wall of the housing and is fixed by a partition wall 10 and a nut 12 that is detachably screwed into the female screw hole 9. nut
The reference numeral 12 denotes a partition wall portion that presses the magnetic cylindrical body 2 toward the partition wall portion 10 side of the housing 5 when screwed into the female screw hole 9 of the housing 5.
A partition 13 and a guide fitting portion 14 formed outside the partition wall 13 in the thrust direction are provided.

The guide rings 3 and 4 are fitted in the nut 12 and the guide fitting portions 11 and 14 of the housing 5 concentrically with the magnetic cylinder 2, and are circumferentially thrust by a plurality of screws 15 and 16 in the thrust direction. It is detachably fixed to each partition wall portion 10 and 13 from the outside.

The screw shaft 1 is made of a magnetic material having a predetermined mechanical strength. On the outer periphery of the screw shaft 1, there are two threads 17 and 18 and screw grooves 19 and 20 having the same lead angle and the same pitch. They are alternately formed in a spiral shape. Thread 17,18 and thread groove 1
9,20 has a square cross section and its thread grooves 19,20
A non-magnetic material 21 such as a synthetic resin is embedded in this so as to have the same diameter as the outer peripheral surfaces of the threads 17, 18.

That is, as shown in FIGS. 4A to 4F, the screw shaft 1 has a large-diameter shaft portion 22 and small-diameter shaft portions 23, 24 at both ends in the thrust direction of the large-diameter shaft portion 22. And a connecting shaft portion 26 provided at the tip of one of the small diameter shaft portions 23, 24 via a screw portion 25. The large-diameter shaft portion 22 has circumferential grooves 27 and 28 formed at both ends in the thrust direction, and both circumferential grooves are formed.
Between threads 27 and 28, the threads 17 and 18 and the grooves 19 and 20 alternate.
The strips are formed in a spiral shape. Then, the non-magnetic material 21 is embedded in the circumferential grooves 27, 28 and the screw grooves 19, 20 so that the large-diameter shaft portion 22 has a smooth, perfect circular shape. Small diameter shaft 2
Bearings are fitted in 3, 24, nuts for fixing bearings are screwed in the screw portion 25, and a coupling for power transmission is fitted in the connecting shaft portion 26 via a key. Has become.

The threads 17,18 and the thread grooves 19,20 are
The cross section is formed in a square shape. The non-magnetic material 21 is preferably a synthetic resin material having abrasion resistance and slidability such as epoxy resin, Teflon resin, nylon, polyacetal, or fluororesin, but other non-magnetic material 21 may be used.

The magnetic cylinder 2 is made of a magnetic material such as a magnetic metal material or a rare earth magnet material. That is, in this embodiment, as shown in FIG. 2, the magnetic cylindrical body 2 is composed of an outer cylindrical body 29 for a cylindrical yoke and an inner cylindrical body 30 fitted inside the outer cylindrical body 29. The inner and outer double structures are formed, and the inner peripheral surface of the inner cylindrical body 30 is machined into a smooth shape so as to have substantially the same inner diameter over the entire length in the thrust direction.

An iron-based metallic material such as mild steel is used for the outer cylinder 29, and a rare earth magnet material, especially a neodymium magnet material containing neodymium, iron and boron is used for the inner cylinder 30. The inner tubular body 30 includes a plurality of ring bodies 31 made of a neodymium magnet material, and is fitted inside the outer tubular body 29 in a state where end faces of the ring bodies 31 in the thrust direction are abutted with each other.

When the magnetic cylinder 2 is manufactured, a plurality of ring bodies 31 made of a neodymium magnet material are prepared, and either the outer peripheral surface of the ring body 31 or the inner peripheral surface of the outer cylindrical body 29 is prepared. After applying the adhesive to one or both of them, each ring body 31 is fitted in the outer cylinder body 29 and fixed with the adhesive, and then the inner peripheral surface of each ring body 31 is smoothed by machining. It may be processed into a shape.

As shown in FIG. 3, the inner cylindrical body 30 has a spiral shape so that the magnetic poles 32 and 33 of the north pole 32 and the south pole 33 can be alternately arranged on the inner peripheral surface side in the thrust direction at regular intervals. It is continuously magnetized. Each N pole 32 and S pole 33 has each thread of the screw shaft 1
The threads 17 and 18 are spirally continuous with the same lead angle and pitch to correspond to threads 17 and 18, respectively.

The magnetic cylinder 2 is composed of magnetic poles 32, 33 on the inner circumference and a screw shaft.
The guide ring on both sides is fitted onto the outer circumference of the screw shaft 1 so that a minute gap is created between the outer circumference of the screw thread 17 and the screw threads 17 and 18.
It is held concentrically with the screw shaft 1 by 3, 4 in a non-contact state. Therefore, the magnetic cylinder 2 and the screw shaft 1 are relatively movable in the thrust direction and the circumferential direction.

The N pole 32 of the magnetic cylinder 2 is the screw thread 1 of the screw shaft 1.
7, 18 and the S pole 33 correspond to the threads 17 and 18 of the screw shaft 1, respectively. Between the screw shaft 1 side and the magnetic cylinder 2 side, the spiral magnetic poles 32 and 33 are N pole of magnetic cylinder 2 over the entire range
32 to thread 17 of screw shaft 1 and thread 18 to magnetic cylinder 2
Closed loop magnetic circuits following the S pole 33 of
The screw shaft 1 is attracted to the outside over the entire circumference by the magnetic action of the N pole 32 and the S pole 33 on the magnetic cylinder 2 side.

Each of the guide rings 3 and 4 is made of a non-magnetic material such as a synthetic resin material having abrasion resistance and sliding property such as nylon, polyacetal, fluororesin, etc. The shaft 1 is slidably inserted in the thrust direction and the circumferential direction.

When manufacturing the screw shaft 1, the large-diameter shaft portion 22
Prepare a material with threads 17,18, thread grooves 19,20 and peripheral grooves 27,28 respectively, set this material in a mold, etc., and then synthesize the non-magnetic material 21 in the mold. A resin material is injected to fill the thread grooves 19, 20 and the peripheral grooves 27, 28 with a synthetic resin material. Then, take out the material from the mold and
After turning 22, the threads 17 and 18 and the non-magnetic material 21 may be ground so that they have the same diameter, and the entire large-diameter shaft portion 22 may be finished to be smooth.

When the magnetic screw is used by incorporating it into a feeder of a machine tool or the like, for example, the connecting shaft portion 26 side of the screw shaft 1 is interlockingly connected to a drive source such as a motor through a coupling or the like, and the housing 5 Fix the flange 7 of to the sliding base.
When the screw shaft 1 is rotated in the forward or reverse direction by the drive source, the magnetic forces of the N pole 32 and the S pole 33 on the magnetic cylinder 2 side act on the tops of the threads 17, 18 of the screw shaft 1. Because
Due to the magnetic force, the magnetic cylinder 2 is rotated with the rotation of the screw shaft 1.
Moves in the thrust direction, and the slide base moves in the thrust direction. At this time, the guide rings 3 and 4 slide on the outer circumference of the screw shaft 1 to keep the screw shaft 1 and the magnetic cylinder 2 out of contact with each other with a minute gap, while the magnetic cylinder 2 is moved to the screw shaft 1. Guide along the thrust direction.

That is, the spiral N pole 32 and S on the magnetic cylinder 2 side
The magnetic force with the pole 33 acts on the top of each screw thread 17, 18 of the screw shaft 1 from the outside through a small gap over the entire range, and each magnetic pole 32, 33 on the magnetic cylinder 2 side and the screw shaft 1 Screw thread 1
Since a suction force acts between 7,18, the magnetic force causes the screw shaft 1 to be constrained in the thrust direction. Therefore, when the screw shaft 1 is rotated to rotate the screw threads 17 and 18 in the circumferential direction, the magnetic poles 32 and 33 on the magnetic cylinder 2 side corresponding to the screw threads 17 and 18 try to follow the rotation, Thread 17,1
Move in the thrust direction according to the lead angle of 8.

Guide rings 3 and 4 are provided on both sides of the magnetic cylinder 2, and the guide rings 3 and 4 slide on the screw shaft 1 in the thrust direction while holding the screw shaft 1 and the magnetic cylinder 2 concentrically. Since they move, the screw shaft 1 and the magnetic cylindrical body 2 can be reliably prevented from contacting each other, and both can be always held in a non-contact state with a constant minute gap.

Moreover, since the screw grooves 19 and 20 of the screw shaft 1 are filled with the non-magnetic material 21 and the outer peripheral surface of the screw shaft 1 including the screw threads 17 and 18 is made smooth, the outer peripheral surface of the screw shaft 1 is Even if the guide rings 3 and 4 slide, the inner rims of the guide rings 3 and 4 are not damaged by the threads 17 and 18, and the guide rings 3 and 4 can be guided along the outer peripheral surface of the screw shaft 1. It can slide smoothly and the durability of the guide rings 3 and 4 is significantly improved.

Further, the thread grooves 19 and 20 of the screw shaft 1 are connected to the non-magnetic material 21.
Since it is embedded with, there is no problem of dust etc. adhering to the inside of the screw grooves 19, 20 unlike in the past, and that dust etc. does not enter the magnetic cylinder 2 through the screw grooves 19, 20. ,
It is possible to reliably prevent dust such as dust from entering the magnetic cylinder 2.

Furthermore, the outer peripheral surface of the screw shaft 1 is smooth,
Even if the gap between the inner peripheral surface of the guide rings 3 and 4 and the outer peripheral surface of the screw shaft 1 is extremely small, the guide rings 3 and 4 can slide smoothly on the outer peripheral surface of the screw shaft 1, so It is possible to prevent dust from entering the magnetic cylindrical body 2 from between the inner peripheral surfaces of the rings 3 and 4 and the outer peripheral surface of the screw shaft 1 as much as possible. Since the outer peripheral surface of the screw shaft 1 is smooth, the corners of the screw threads 17 and 18 of the screw shaft 1 may be injured or damaged by contact with other objects during assembly, inspection, etc. There is no problem such as damage, and the appearance of the entire screw shaft 1 is improved.

In addition, the non-magnetic material 21 is embedded in the thread grooves 19 and 20 to form a smooth outer peripheral surface.
Since there is no damage, etc. 4, the cross-sectional shape of the threads 17 and 18 can be made rectangular so that the magnetic flux leakage from the magnetic poles 32 and 33 on the magnetic nut body 6 side can be minimized. In other words, in other words, the shapes of the screw threads 17, 18 can be freely selected and determined only from the viewpoint of reducing the leakage magnetic flux, and it is easy to secure the thrust force of the magnetic screw.

FIG. 5 illustrates a second embodiment of the present invention,
The inner cylindrical body 30 of the magnetic cylindrical body 2 is formed as an integral structure over the entire length in the thrust direction. Also in this case, the same effect as that of the first embodiment can be obtained by filling the thread grooves 19 and 20 of the screw shaft 1 with the non-magnetic material 21 to form a smooth shape.

6 to 8 exemplify a third embodiment of the present invention, in which the thread grooves 19, 20 of the screw shaft 1 are filled with a non-magnetic material 21 to form a smooth shape, while the guide rings 3, 4 is provided with air seal means 34. As shown in FIGS. 6 and 7, each of the guide rings 3 and 4 is provided with an air seal means 34 therein, and the air ejected from the air seal means 34 causes the air into the magnetic nut body 6. It is designed to prevent the intrusion of dust and the like.

As shown in FIG. 8 on the guide ring 3 and 4 side, each air seal means 34 has an air inlet 35 opened from the outer end surface of each guide ring 3 and 4 toward the inner side in the thrust direction. And an air guide groove 36 formed circumferentially around the inner peripheral surface of each of the guide rings 3 and 4, and a communication hole 37 for diametrically communicating between the air introduction port 35 and the air guide groove 36.
And an air ejection portion 38 formed on the entire inner circumference of the guide rings 3 and 4 so as to eject air from the air guide groove 36 toward the outer side in the thrust direction. ing.

The air guide groove 36 is formed by the guide ring 3,
In order not to reduce the contact area with the screw shaft 1 on the inner peripheral side of 4, it is provided so as to be offset from the center in the thrust direction. In this embodiment, when low-pressure air from an air source is supplied to the air introduction port 35 of the air seal means 34 via a flexible hose or the like, the air is sent to the air guide groove 36 side through the communication hole 37. Go. Air guide groove 36
The air supplied to the air blows around the screw shaft 1 along the air guide groove 36 and the air blower 38 along the entire circumference of the screw shaft 1 because the air blower 38 on the outside is in a throttled state. Spouts outward from the thrust direction.

For this reason, an air curtain flowing outward in the thrust direction is formed on the entire circumference between the inner peripheral surfaces of the guide rings 3 and 4 and the outer peripheral surface of the screw shaft 1, and the magnetic curtain is formed by this air curtain. It is possible to prevent dust from entering the body 6. Also, while air from the air seal means 34 blows off dust and the like on the outer circumference of the screw shaft 1, the guide rings 3 and 4 slide thereafter, so that the magnetic nut body 6 is simply
Not only can dust be prevented from entering inside, but damage to the guide rings 3 and 4 is also reduced.

In particular, the thread grooves 19 and 20 of the screw shaft 1 are connected to the non-magnetic material 21.
Since the outer peripheral surface of the screw shaft 1 is made smooth by embedding with, it is possible to obtain a sufficient air sealing effect while reducing the air ejection amount compared to the case without the non-magnetic material 21. Therefore, there is an advantage that the air seal means 34 can be easily and miniaturized.

In addition, since the air seal means 34 is provided on the guide rings 3 and 4, the guide rings 3 and 4 and the air seal means 34 can be used in common, and the structure is simplified and the number of parts can be reduced. Further, the guide rings 3 and 4 are the guide fitting portion 1
Since it fits inside 1,14 and is protected by the housing 5 from the outside, the guide ring 3,4, air seal means 34
Can be easily made of a synthetic resin material or the like, and even if it is made of a synthetic resin, it is not necessary to separately provide a cover.

FIGS. 9 and 10 illustrate a fourth embodiment of the present invention, in which the guide rings 3 and 4 and the air seal means 34 are separated from each other, and the air seal means 34 is provided outside the guide rings 3 and 4 in the housing. It is provided on both sides in the thrust direction of No. 5. The air seal means 34 has an air guide groove on the ring body 39.
36, the air jet part 38, etc. are formed, and the ring body 39
Is removably attached to the housing 5 with screws 40. In this way, the guide rings 3 and 4 and the air seal means
By separating 34 from each other, it is possible to sufficiently secure the area of the inner peripheral surface of the guide rings 3 and 4 that comes into contact with the screw shaft 1.

11 and 12 illustrate the fifth embodiment of the present invention, in which the first magnetic nut body 6a and the second magnetic nut body 6a provided with the guide rings 3 and 4 with the air seal means 34 in the housing 5. The nut body 6b is arranged side by side in the thrust direction, and the second magnetic nut body 6b is rotated in the circumferential direction within a range of 90 degrees so that the thrust force of the entire magnetic screw can be adjusted.

The second magnetic nut body 6b is provided with an operating portion 44 on the outer periphery of the flange portion 41 and is rotatably fitted in the housing 5. The flange portion 41 has a long hole 42 in the circumferential direction.
Is formed, and the magnetic nut body 6 is fixed to the housing 5 at an arbitrary adjustment position by the screw 43 inserted through the elongated hole 42.

The first magnetic nut body 6a is fitted in the housing 5, and the flange portion 45 thereof is screwed into the housing 5.
It is fixed to. In this embodiment, the second magnetic nut body 6b is rotated in the circumferential direction so that the first magnetic nut body 6a and the second magnetic nut body 6b
By adjusting the relative position with respect to the magnetic nut body 6b in the circumferential direction, either one of the magnetic poles 32, 33 of both magnetic nut bodies 6a, 6b or both of the magnetic nut bodies 6a, 6b and the screw of the screw shaft 1 is screwed. Mountain
The phase between 17 and 18 changes, and the thrust force can be adjusted.

That is, in the adjustment, first, the screw 43 is loosened to release the fixation of the second magnetic nut body 6b to the housing 5, and then the operation portion 44 on the outer periphery of the flange portion 41 is grasped to make the second adjustment.
The magnetic nut body 6b is rotated in the circumferential direction. Then, the second magnetic nut body 6b rotates about the axis in the housing 5, and then the screw 43 is tightened to fix the second magnetic nut body 6b to the housing 5 at the adjustment position. This makes the first
Since the relative positions of the magnetic nut body 6a and the second magnetic nut body 6b are displaced in the circumferential direction, between the magnetic poles 32 and 33 or both of the magnetic nut bodies 6a and 6b and the screw threads 17 and 18 of the screw shaft 1. A phase difference occurs in the magnetic field, and the thrust force of the entire magnetic screw changes.

In this case as well, the outer peripheral surface of the screw shaft 1 is made smooth and the air seal means 34 is provided, so that the same operation as described above can be performed. Note that FIG. 12 shows the second magnetic nut body.
6b shows a state in which the thrust force is adjusted by rotating 6b about the axis of the screw shaft 2 by 45 °.

FIGS. 13A to 13F show the sixth embodiment of the present invention.
The screw shaft 1 is a two-thread screw type in which a small diameter shaft portion 24 and a screw portion 25 are provided on one end side of the large diameter shaft portion 22. In this case, the screw shaft 1 is
It can be used by supporting 1 in a cantilevered manner.

14A to 14F show the seventh embodiment of the present invention.
The screw shaft 1 is a single-thread screw type in which a thread 17 and a thread groove 19 are provided in the large-diameter shaft portion 22 one by one, and a non-magnetic material 21 is embedded in the thread groove 19. It is made smooth. Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments.

For example, the guide rings 3 and 4, the housing 5
The air seal means 34 and the like may be integrally formed of a synthetic resin material. In this case, the magnetic cylinder 2 may be molded in the housing 5 by inserting the magnetic cylinder 2 into a mold for molding the housing 5 and injecting a synthetic resin material.

Threads 17, 18 and thread grooves 19, 20 of the screw shaft 1
The shape may be trapezoidal, mountain-shaped, etc. in addition to the rectangular shape. However,
If the threads 17 and 18 and the thread grooves 19 and 20 are formed in a chevron shape, for example, provide recesses or protrusions in the thread grooves 19 and 20, and use resin molding or the like to attach the nonmagnetic material 21 to the thread grooves 19 and 20. If the non-magnetic material 21 is engaged with the concave portion or the convex portion at the time of embedding, the non-magnetic material 21 can be prevented from falling off. In an embodiment,
Although the air seal means 34 is illustrated as the seal means, other means may be adopted.

[0053]

According to the present invention as set forth in claim 1, there is provided a screw shaft made of a magnetic material and having a thread and a thread groove formed on the outer peripheral surface thereof, and a gap is provided on the outer periphery of the screw shaft. In a magnetic screw equipped with a magnetic nut body that is fitted and has a magnetic pole spirally magnetized corresponding to the screw thread of the screw shaft on the inner peripheral surface side, a non-magnetic material is provided in the screw groove of the screw shaft. embedded,
Since the outer peripheral surface of the screw shaft is configured to be smooth, it is possible to prevent the intrusion of dust such as dust into the magnetic nut body, and to make the shape of the screw thread square to reduce leakage magnetic flux, The guide ring and other damages can be prevented, the handling at the time of assembly etc. can be facilitated, and the appearance is improved.

According to the invention of claim 2, in the invention of claim 1, the screw shafts are arranged substantially concentrically to the magnetic nut body on both sides in the thrust direction of the magnetic nut body. Since the guide ring for holding and guiding slidably is provided, the magnetic nut body and the screw shaft can be held substantially concentrically with a minute gap, and the guide ring can be prevented from being damaged by a screw thread.

According to the present invention of claim 3, in the invention of claim 1 or 2, seals are provided on both sides of the magnetic nut body in the thrust direction to prevent dust from entering the magnetic nut body. Since the means is provided, the intrusion of dust into the magnetic nut body can be prevented more reliably, and since the outer circumference of the screw shaft is smooth, the sealing can be performed more reliably with a simple sealing means.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, since the air sealing means for sealing with air is used as the sealing means, the structure of the sealing means is used. Can be easily and easily sealed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a magnetic screw according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the magnetic cylinder of the magnetic screw according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a magnetic pole in a magnetized state according to the first embodiment of the present invention.

FIG. 4 shows the screw shaft of the first embodiment of the present invention,
(A) is a front view, (B) is a bottom view, (C) is a plan view,
(D) is a rear view, (E) is an enlarged left side view, and (F) is an enlarged right side view.

FIG. 5 is a partially cutaway front view of a magnetic screw according to a second embodiment of the present invention.

FIG. 6 is a partially cutaway front view of a magnetic screw according to a third embodiment of the present invention.

FIG. 7 is a side view of the magnetic screw according to the third embodiment of the present invention.

FIG. 8 is a side view of an essential part showing a third embodiment of the present invention.

FIG. 9 is a partially cutaway front view of a magnetic screw according to a fourth embodiment of the present invention.

FIG. 10 is a side view of a magnetic screw according to a fourth embodiment of the present invention.

FIG. 11 is a partially cutaway front view of a magnetic screw according to a fifth embodiment of the present invention.

FIG. 12 is a side view of a magnetic screw according to a fifth embodiment of the present invention.

FIG. 13 shows a screw shaft according to a sixth embodiment of the present invention,
(A) is a front view, (B) is a bottom view, (C) is a plan view,
(D) is a rear view, (E) is an enlarged left side view, and (F) is an enlarged right side view.

FIG. 14 shows a screw shaft according to a seventh embodiment of the present invention,
(A) is a front view, (B) is a bottom view, (C) is a plan view,
(D) is a rear view, (E) is an enlarged left side view, and (F) is an enlarged right side view.

[Explanation of symbols]

 1 Screw shaft 2 Magnetic cylinder 3,4 Guide ring 5 Housing 6,6a, 6b Magnetic nut body 17,18 Thread 19,20 Thread groove 21 Non-magnetic material 32 N pole 33 S pole 34 Air seal means

Claims (4)

[Claims] 1. A screw shaft made of a magnetic material and having a screw thread and a screw groove formed on the outer peripheral surface thereof, and a screw shaft which is fitted around the outer peripheral surface of the screw shaft with a gap and is provided on the inner peripheral surface side of the screw shaft. In a magnetic screw including a magnetic nut body in which magnetic poles are spirally magnetized corresponding to a screw thread, a non-magnetic material is embedded in the screw groove of the screw shaft to smooth the outer peripheral surface of the screw shaft. A magnetic screw characterized by being constructed. 2. A guide ring is provided on both sides of the magnetic nut body in the thrust direction so as to slidably guide the screw shaft in a substantially concentric manner with respect to the magnetic nut body. The magnetic screw according to claim 1. 3. The magnetic screw according to claim 1, wherein sealing means is provided on both sides of the magnetic nut body in the thrust direction to prevent dust from entering the magnetic nut body. 4. The air sealing means for sealing with air is used as the sealing means.
The magnetic screw according to any one of 1 to 3.