JP3153459B2 - Magnetic screw - Google Patents

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 thread and a thread groove formed on an outer peripheral surface thereof, a screw shaft fitted over the outer periphery of the screw shaft with a gap therebetween, and a screw screwed on an inner peripheral surface side. A magnetic nut body in which magnetic poles are helically magnetized corresponding to the thread of the shaft, and utilizing the magnetic force of the magnetic poles of the magnetic nut body, one of the screw shaft and the magnetic nut body, Alternatively, various types of magnetic screws have been proposed that are configured to convert a rotational motion into a rotational or linear motion.

[0003]

According to this magnetic screw, one of the screw shaft and the magnetic nut is converted into a linear or rotational motion into the other rotational or linear motion by the magnetic force of the magnetic nut. Since it is not necessary to directly contact the screw shaft and the magnetic nut body, it can be used without lubrication and can prevent environmental pollution and noise from being worn out.
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 screw groove of the screw shaft or the dust passes through the screw groove depending on the use environment. The magnetic nut body may enter the magnetic nut body and adhere to or be damaged on the inner peripheral side of the magnetic nut body.

In the case of a normal sliding screw or the like, the nut body slides along the outer peripheral surface of the screw shaft. Therefore, even if there is an adhering substance on the screw groove, the nut body slides along the screw groove. When moving, it is possible to remove the deposits with a nut body, but in the case of a magnetic screw, since 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 deposits adhering to the grooves by the magnetic nut body.

In addition, when the magnetic powder is used in an environment where magnetic powder such as iron powder is likely to be generated, if the magnetic powder adheres to the thread groove due to the residual magnetism of the magnetic nut, the outer periphery of the portion is covered with the magnetic nut. When passing through, there is also a problem that the magnetic powder is attracted by the magnetic force of the magnetic pole on the inner peripheral surface and adheres to the magnetic nut body and the inner peripheral surface, 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 small. Once dust invades the magnetic nut, it is difficult to remove the dust. At the same time, the dust and other deposits that have accumulated in the magnetic nut have formed between the magnetic nut and the thread of the screw shaft. There is also a possibility that problems such as biting into the body may occur.

Further, in the case where a guide ring is provided on both sides of the magnetic nut body in the thrust direction in such a manner that the screw shaft is held substantially concentrically with respect to the magnetic nut body and is guided in a slidable manner. However, there is a disadvantage that the inner peripheral side of the guide ring is damaged. Particularly, if the screw thread of the screw shaft is formed into 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 there is an advantage that the leakage magnetic flux can be reduced as much as possible. There is a problem that the damage of the guide ring due to the corner of the mountain becomes large.

Further, since there is a thread on the outer periphery of the screw shaft, an operator may be injured at the corner of the screw thread or the screw shaft may come into contact with another member even when the magnetic screw is assembled into a required part. As a result, there is a problem that another member or the corner of the thread is damaged. In view of such conventional problems, the present invention can prevent the entry of dust and the like into the magnetic nut body, prevent the guide ring and other damage, and further facilitate the handling of the magnetic screw during assembly and the like. The purpose is to provide.

[0010]

According to the present invention, there is provided a screw shaft made of a magnetic material and having a thread and a thread groove formed on an outer peripheral surface thereof. A magnetic screw having a magnetic nut body spirally magnetized corresponding to the screw thread of the screw shaft on the peripheral surface side, wherein a non-magnetic material is embedded in the screw groove of the screw shaft. The outer peripheral surface of the shaft is formed in a smooth shape, and guide rings are provided on both sides in the thrust direction of the magnetic nut body so as to hold the screw shaft substantially concentrically with respect to the magnetic nut body and slidably guide the screw shaft. , the respective guide ring, provided an air sealing means for preventing dust from entering into the magnetic nut body, the air
The sealing means is provided around the entire inner peripheral surface of the guide ring.
Air guide groove formed in
The air guide groove is formed in the circumferential direction all around the circumferential surface.
Air ejection section that ejects air outward in the thrust direction
It is provided with .

[0011]

[0012]

[0013]

[0014]

Reference Example FIGS. 1 to 4 show a first reference example of a magnetic screw.
Show. This magnetic screw is, as shown in FIG.
A magnetic cylinder 2 fitted around the outer periphery of the screw shaft 1 with a gap; a pair of guide rings 3 and 4 provided on both sides of the magnetic cylinder 2 in the thrust direction; And a housing 5 for holding the guide rings 3 and 4.
The magnetic cylinder 2, the guide rings 3, 4 and the housing 5
The magnetic nut body 6 is constituted by the above.

The housing 5 is formed in a cylindrical shape from a stainless material or the like. A flange 7 for mounting is integrally formed on the outer periphery of one end of the housing 5 in the thrust direction. Inside the housing 5, a cylindrical fitting portion 8 is formed at the center in the thrust direction, a female screw hole 9 is formed at one end of the cylindrical fitting portion 8, and a partition wall portion is formed at the other end.
Guide fitting portions 11 are formed concentrically with the cylindrical body fitting portions 8 via the respective 10.

The magnetic cylinder 2 is a cylinder fitting portion 8 of the housing 5.
And is fixed by a nut 12 which is detachably screwed into the partition wall portion 10 and the female screw hole 9. nut
The partition wall 12 presses the magnetic cylinder 2 toward the partition wall 10 of the housing 5 when screwed into the female screw hole 9 of the housing 5.
13 and a guide fitting portion 14 formed on the outside of the partition 13 in the thrust direction.

The guide rings 3, 4 are fitted to the nut 12 and the guide fitting portions 11, 14 of the housing 5 concentrically with the magnetic cylinder 2, and are provided in the circumferential direction by a plurality of screws 15, 16 in the thrust direction. Are detachably fixed to the partition portions 10 and 13 from 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, two threads 17, 18 and thread grooves 19, 20 having the same lead angle and the same pitch are provided. It is formed in a spiral shape alternately. Thread 17, 18 and thread groove 1
9 and 20 have square cross sections, and their thread grooves 19 and 20
A non-magnetic material 21 such as a synthetic resin is embedded therein so as to have the same diameter as the outer peripheral surfaces of the threads 17 and 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 of the large-diameter shaft portion 22 in the thrust direction. And a connecting shaft portion 26 provided at the tip of one of the small-diameter shaft portions 23 and 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.
Between 27 and 28, threads 17, 18 and thread grooves 19, 20 alternately
It is formed helically one by one. The non-magnetic material 21 is embedded in the circumferential grooves 27 and 28 and the screw grooves 19 and 20 so that the entire large-diameter shaft portion 22 becomes a smooth perfect circle. Small diameter shaft 2
Bearings are fitted to 3, 24, a nut for fixing the bearing is screwed to the screw part 25, and a coupling for power transmission is fitted to the connecting shaft part 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 nonmagnetic material 21 is preferably a synthetic resin material having abrasion resistance and slipperiness, such as an epoxy resin, a Teflon resin, nylon, polyacetal, and a fluororesin, but other nonmagnetic materials 21 may be used.

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

The outer cylinder 29 is made of an iron-based metal material such as mild steel, and the inner cylinder 30 is made of a rare earth magnet material, especially a neodymium magnet material containing neodymium, iron and boron. The inner cylindrical body 30 includes a plurality of ring bodies 31 made of neodymium magnet material, and is fitted inside the outer cylindrical body 29 with the end faces of the respective ring bodies 31 in the thrust direction abutting each other.

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

As shown in FIG. 3, the inner cylindrical body 30 is spirally formed on the inner peripheral surface thereof so that the magnetic poles 32 and 33 of the N pole 32 and the S pole 33 can be alternately arranged at regular intervals in the thrust direction. It is magnetized continuously. Each N pole 32 and S pole 33 is a screw thread of the screw shaft 1.
In order to correspond to 17,18, respectively, it is spirally continuous at the same lead angle and the same pitch as the threads 17,18.

The magnetic cylinder 2 has inner magnetic poles 32 and 33 and a screw shaft.
1 is screwed on the outer circumference of the screw shaft 1 so that a small gap is formed between the outer peripheral threads 17 and 18 and the guide rings on both sides.
It is held concentrically with the screw shaft 1 in a non-contact state by 3 and 4. 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 thread 1 of the screw shaft 1.
7 and 18, the S pole 33 corresponds to the threads 17 and 18 of the screw shaft 1, respectively. Between the screw shaft 1 side and the magnetic cylinder 2 side, each of the helical magnetic poles 32 and 33 is provided. N pole of magnetic cylinder 2 over the entire range
From 32, through the thread 17 and thread 18 of the screw shaft 1, the magnetic cylinder 2
A closed loop magnetic circuit following the S pole 33 is formed,
The screw shaft 1 is attracted outward over the entire circumference by the magnetic force of the N pole 32 and the S pole 33 on the side of the magnetic cylinder 2.

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

When the screw shaft 1 is manufactured, the large-diameter shaft portion 22 is used.
A material having threads 17,18, thread grooves 19,20 and circumferential grooves 27,28 formed on each other is prepared, and after setting this material in a mold or the like, a synthetic material for the non-magnetic material 21 is placed in the mold. A resin material is injected, and a synthetic resin material is embedded in the screw grooves 19 and 20 and the circumferential grooves 27 and 28. Then, the material is taken out of the mold and the large-diameter shaft
After turning the 22, the threads 17, 18 and the non-magnetic material 21 may be polished so as to have exactly the same diameter, and the entire large-diameter shaft portion 22 may be finished in a smooth shape.

When the magnetic screw is used by being incorporated in a feeder of a machine tool, for example, the connection shaft 26 side of the screw shaft 1 is operatively connected to a drive source such as a motor via a coupling or the like, and The flange 7 is fixed to a slide table or the like.
When the screw shaft 1 is rotated in the forward or reverse direction by the driving source, the magnetic force of the N pole 32 and the S pole 33 on the magnetic cylinder 2 acts on the tops of the threads 17, 18 of the screw shaft 1. Because
Due to the magnetic action, the magnetic cylinder 2
Moves in the thrust direction, and the slide moves in the thrust direction. At this time, each of the guide rings 3 and 4 slides on the outer periphery of the screw shaft 1 to keep the magnetic cylinder 2 on the screw shaft 1 while keeping the screw shaft 1 and the magnetic cylinder 2 in a non-contact state with a small gap. Along the thrust direction.

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

Guide rings 3, 4 are provided on both sides of the magnetic cylinder 2, and the guide rings 3, 4 slide on the screw shaft 1 in the thrust direction while holding the screw shaft 1 and the magnetic cylinder 2 concentrically. Therefore, the contact between the screw shaft 1 and the magnetic cylinder 2 can be reliably prevented, and the two can always be kept in a non-contact state with a constant small gap.

Further, since the screw grooves 19 and 20 of the screw shaft 1 are embedded with the non-magnetic material 21 to make the outer peripheral surface of the screw shaft 1 including the threads 17 and 18 smooth, the outer peripheral surface of the screw shaft 1 is formed. Even when the guide rings 3 and 4 slide, the threads 17 and 18 of the guide rings 3 and 4 do not damage the inner peripheral side of the guide rings 3 and 4, and the guide rings 3 and 4 move along the outer peripheral surface of the screw shaft 1. In addition to smooth sliding, the durability of the guide rings 3 and 4 is significantly improved.

The screw grooves 19 and 20 of the screw shaft 1 are
In this way, there is no problem that dust and the like adhere to the screw grooves 19 and 20 unlike the conventional case, and the dust and the like do not enter the magnetic cylinder 2 through the screw grooves 19 and 20. ,
Dust such as dust can be reliably prevented from entering the magnetic cylinder 2.

Further, the outer peripheral surface of the screw shaft 1 is smooth,
Even if the gap between the inner peripheral surfaces 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 on the outer peripheral surface of the screw shaft 1 smoothly. Intrusion of dust into the magnetic cylinder 2 from between the inner peripheral surfaces of the rings 3 and 4 and the outer peripheral surface of the screw shaft 1 can be prevented as much as possible. In addition, since the outer peripheral surface of the screw shaft 1 is smooth, even when handling during assembly, inspection, etc., the screw shaft 1 may be injured at the corners of the threads 17, 18 or may be damaged by contact with other objects. There is no problem such as damage, and the aesthetic appearance of the entire screw shaft 1 is also 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 or the like, the cross-sectional shape of the threads 17 and 18 can be made square, and the leakage magnetic flux of each of the magnetic poles 32 and 33 on the magnetic nut body 6 side can be reduced as much as possible. In other words, in other words, the shape of the 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 shows a second embodiment of the magnetic screw, in which the inner cylindrical body 30 of the magnetic cylindrical body 2 is integrally formed over the entire length in the thrust direction. Again, by forming a smooth shape to fill the screw groove 19, 20 of the screw shaft 1 with a non-magnetic material 21, the same effects as the first embodiment.

[0037]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
It will be described based on. FIGS. 6 to 8 illustrate a first embodiment of the present invention, in which the magnetic screw is formed by screw grooves 19,
20 is filled with a non-magnetic material 21 to form a smooth shape, while each of the guide rings 3 and 4 is provided with an 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.
The air blown out from the air sealing means 34 prevents dust and the like from entering the magnetic nut body 6.

As shown in the guide rings 3 and 4 in FIG. 8, each air seal means 34 has an air inlet 35 opened from the outer end surface of each guide ring 3 and 4 inward in the thrust direction. And an air guide groove 36 formed in the circumferential direction on the entire inner peripheral surface of each of the guide rings 3 and 4, and a communication hole 37 for diametrically communicating between the air inlet 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 outside in the thrust direction. ing.

It should be noted that the air guide groove 36 is formed in the guide ring 3,
In order not to reduce the contact area with the screw shaft 1 on the inner peripheral side of 4, an offset is provided outside the center in the thrust direction. In this embodiment, when low-pressure air from an air source is supplied to the air inlet 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 jetting portion 38 is turned around the entire circumference of the screw shaft 1 along the air guide groove 36 because the air jetting portion 38 on the outer side is in a throttle state, and the air jetting portion 38 is formed along the entire circumference of the screw shaft 1. 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 air curtain is formed by the air curtain. Dust can be prevented from entering the body 6. In addition, since the dust from the outer periphery of the screw shaft 1 is blown off by the air from the air sealing means 34, the guide rings 3 and 4 slide thereafter.
In addition to preventing dust from entering inside, damage to the guide rings 3 and 4 is reduced.

In particular, the screw grooves 19 and 20 of the screw shaft 1 are
And the outer peripheral surface of the screw shaft 1 is configured to be smooth, so that a sufficient air sealing effect can be obtained while reducing the amount of air ejection compared to the case where the non-magnetic material 21 is not provided. Therefore, there is an advantage that the air seal means 34 can be simplified and reduced in size.

Further, since the air seal means 34 is provided on the guide rings 3, 4, the guide rings 3, 4 can be used as the air seal means 34, and the structure is simplified and the number of parts can be reduced. Furthermore, guide rings 3 and 4 are
1, 14 and are protected from outside by the housing 5, so that the guide rings 3, 4 and the air sealing means 34
Can be easily manufactured using a synthetic resin material or the like, and there is no need to separately provide a cover even if the cover is made of synthetic resin.

[0043]

FIGS. 9 and 10 illustrate a second embodiment of the present invention, in which a first magnetic nut body 6a having guide rings 3, 4 with air seal means 34 in a housing 5 and a second magnetic nut body 6a.
The magnetic 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 to adjust the thrust force of the entire magnetic screw. .

The second magnetic nut body 6b has an operation portion 44 provided 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.
The magnetic nut 6 is fixed to the housing 5 at an arbitrary adjustment position by a screw 43 inserted into the elongated hole 42.

The first magnetic nut body 6 a is fitted inside the housing 5, and its flange 45 is screwed to 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 is
By adjusting the relative position with respect to the magnetic nut body 6b in the circumferential direction, one of the magnetic poles 32, 33 of the two magnetic nut bodies 6a, 6b or both of the magnetic nut bodies 6a, 6b and the screw of the screw shaft 1 are screwed. Mountain
The phase between 17, 18 changes, and the thrust force can be adjusted.

That is, in the adjustment, first, the screw 43 is loosened to release the fixing of the second magnetic nut body 6b to the housing 5, and then the operating portion 44 on the outer periphery of the flange portion 41 is grasped to perform the second
The magnetic nut body 6b is rotated in the circumferential direction. Then, the second magnetic nut body 6b rotates around the axis inside the housing 5, so that 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 shifted in the circumferential direction, the gap between one or both of the magnetic poles 32, 33 of the magnetic nut bodies 6a, 6b and the threads 17, 18 of the screw shaft 1 is increased. Causes a phase difference, and the thrust force of the entire magnetic screw changes.

In this case as well, the outer peripheral surface of the screw shaft 1 can be formed in a smooth shape and the air seal means 34 can be provided to implement the same as described above. FIG. 10 shows the second magnetic nut body.
6B shows a state in which the thrust force is adjusted by rotating the shaft 6b around the axis of the screw shaft 1 by 45 °.

[0049] (A) to the FIG. 11 (F) the third of the present invention
The screw shaft 1 is of a double thread type in which a small-diameter shaft portion 24 and a screw portion 25 are provided at one end of a large-diameter shaft portion 22. In this case, the screw shaft 1 is
1 can be used in a cantilevered manner.

[0050] to 12 of (A) (F) the fourth of the present invention
The screw shaft 1 is a single-threaded screw type in which a large-diameter shaft portion 22 is provided with a thread 17 and a thread groove 19 one by one, and a non-magnetic material 21 is embedded in the thread groove 19. It has been smoothed. As mentioned above, although each Example of this invention was described in detail, this invention is not limited to these Examples.

For example, the guide rings 3, 4 and the housing 5
The air sealing means 34 and the like may be integrally formed of a synthetic resin material. In this case, the magnetic cylinder 2 may be put into a mold for molding the housing 5, a synthetic resin material is injected, and the magnetic cylinder 2 may be molded into the housing 5 or the like.

The screw threads 17 and 18 and the screw grooves 19 and 20 of the screw shaft 1
May have a trapezoidal shape, a mountain shape, or the like in addition to a square shape. However,
When the screw threads 17, 18 and the screw grooves 19, 20 are formed in a mountain shape, etc., a concave portion or a convex portion is provided in the screw grooves 19, 20, and the nonmagnetic material 21 is formed in the screw grooves 19, 20 by resin molding or the like. When the nonmagnetic material 21 is configured to be engaged with the concave or convex portion when embedding, the nonmagnetic material 21 can be prevented from falling off.

[0053]

According to the present invention, a screw shaft made of a magnetic material and having a thread and a thread groove formed on the outer peripheral surface, and is fitted over the outer periphery of the screw shaft with a gap therebetween and has an inner peripheral surface. A magnetic nut body having a magnetic pole helically magnetized corresponding to the screw thread of the screw shaft, a non-magnetic material is embedded in the screw groove of the screw shaft, Since the outer peripheral surface is configured to be smooth, it is possible to prevent intrusion of dust such as dust into the magnetic nut body, and to reduce the leakage flux, even if the shape of the thread is square in cross section, the guide ring, etc. Damage can be prevented, and handling during assembly and the like can be facilitated, and the appearance is also improved.

Also, guide rings are provided on both sides of the magnetic nut body in the thrust direction so as to guide the screw shaft substantially concentrically with respect to the magnetic nut body and to guide them slidably. The body and the screw shaft can be held substantially concentrically with the minute gap, and the guide ring can be prevented from being damaged by the thread.

In addition , on both sides of the magnetic nut body in the thrust direction, dust is prevented from entering the magnetic nut body.
Since the air sealing means is provided, intrusion of dust into the magnetic nut body can be more reliably prevented, and since the outer periphery of the screw shaft is smooth , sealing can be more reliably and simply performed with a simple air sealing means. .

[0056]

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a magnetic screw showing a first reference example .

FIG. 2 is a sectional view of a magnetic cylinder of a magnetic screw showing a first reference example ;

FIG. 3 is a cross-sectional view illustrating a magnetized state of a magnetic pole according to a first reference example .

4A and 4B show a screw shaft of the first reference example , where FIG. 4A is a front view, FIG. 4B is a bottom view, FIG. 4C is a plan view, FIG. 4D is a rear view, and FIG. FIG. 7F is an enlarged right side view.

FIG. 5 is a partially cutaway front view of a magnetic screw showing a second reference example .

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

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

FIG. 8 is a side view of a main part showing the first embodiment of the present invention.

FIG. 9 is a partially cutaway front view of a magnetic screw showing a second embodiment of the present invention.

FIG. 10 is a side view of a magnetic screw showing a second embodiment of the present invention.

FIG. 11 shows a screw shaft according to a third 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. 12 shows a screw shaft according to a fourth 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 (2)

(57) [Claims] 1. A screw shaft made of a magnetic material and having a thread and a screw groove formed on an outer peripheral surface thereof, and fitted around an outer periphery of the screw shaft with a gap therebetween and having the inner peripheral surface side of the screw shaft. A magnetic nut body having a magnetic pole helically magnetized corresponding to the screw thread, wherein 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 guide ring is provided on each side of the magnetic nut body in the thrust direction, the guide ring holding the screw shaft substantially concentrically with respect to the magnetic nut body and slidably guiding the screw shaft. Air seal means for preventing dust from entering the magnetic nut body is provided , and the air seal means
An air plan formed in the circumferential direction all around the inner peripheral surface of the drilling
Formed in the circumferential direction on the entire circumference of the inner groove and the inner peripheral surface of the guide ring
And from the air guide groove outward in the thrust direction
A magnetic screw, comprising: an air ejection section for ejecting air . 2. The magnetic screw according to claim 1, wherein the guide ring is made of a synthetic resin having wear resistance and slipperiness.