JPH07280061A - Magnetic screw - Google Patents

Abstract

PURPOSE:To surely hold both a shaft and a cylindrical body in a non-contact state and to make a gap between the two very small by using simple structure. To convert rotational or rectilinear movement on one side into the rotational or rectilinear movement on the other side smoothly and surely by using the action of the magnetic force. CONSTITUTION:A shaft 1 and a cylindrical body 5, which encloses or covers the periphery of this shaft l leaving a gap, are manufactured from magnetic material, while magnetic poles are placed spirally on at least one side of the shaft 1 and the cylindrical body 2. In addition, guide rings 3, 4, which hold the shaft 1 in almost coaxial with respect to the cylindrical body 2 and which guide the shaft l in a freely slidable manner, are placed on both sides of the cylindrical body 2 in the direction of the shaft center line.

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 equipment.

[0002]

2. Description of the Related Art For example, as a feeder for machine tools and other various precision instruments, there are a feeder utilizing a slide screw or a ball screw and a feeder utilizing a magnetic screw. A feeder using a sliding screw or a ball screw is disclosed in Japanese Utility Model Publication No. 58-40.
As disclosed in Japanese Laid-Open Patent Application No. 377, Japanese Utility Model Publication No. 60-30511, etc., a screw shaft and a nut are provided, and the screw raceway surface between the screw shaft and the nut makes sliding contact or rolling contact with a ball, thereby screwing the screw. It has a structure that converts the rotational movement of the shaft into the linear movement of the nut.

Further, a feeding device using a magnetic screw is disclosed in JP-A-49-101771, JP-A-54-15695.
As disclosed in Japanese Patent Laid-Open No. 9 and the like, a screw shaft and a tubular body fitted around the outer periphery of the screw shaft with a gap therebetween are made of a magnetic material, and a spiral is provided on at least one of the screw shaft and the tubular body. A magnetic pole having a circular shape is provided, and the magnetic force of this magnetic pole converts the rotational movement of the screw shaft into the linear movement of the cylindrical body.

[0004]

In all of the conventional feeders using a sliding screw or the like, the screw shaft, the nut, etc. are in metal contact with each other, and one movement is transmitted to the other through this metal contact. , There are the following problems. That is, in a feeder using a sliding screw or the like, there is always frictional resistance due to metal contact of the screw raceway surface, so it is necessary to coat the screw raceway surface with a wear resistant material and lubricate it with solid lubricant, grease or lubricating oil. There is.

Moreover, even if such measures are taken, there is a limit to reducing the frictional resistance, and the mechanical accuracy is lowered, such as the linear expansion of the screw shaft due to the heat generation due to the frictional resistance, and at the same time the machine caused by wear is reduced. There is a problem in that the accuracy of the image is lowered and the durability is lowered. Further, there are drawbacks that cause environmental pollution due to the use of lubricants, greases, etc., environmental pollution due to wear powder generated due to wear of metal contact parts, and noise problems caused due to vibration of metal contact parts. .

In the feeding device using a magnetic screw, the rotational motion of the screw shaft is converted into the linear motion of the cylinder by the magnetic force of the magnetic poles, and it is not necessary to directly contact the screw shaft and the cylinder. Not only can it be used without lubrication, but it also has the advantage of being able to prevent environmental pollution due to wear, noise, etc., and improve the durability, etc., and can solve the problems of the feeding device using slide screws or ball screws. .

On the other hand, in this type of magnetic screw, the magnetic force of the magnetic poles between the screw shaft and the cylindrical body, especially the attractive force thereof is utilized, so that the screw shaft and the cylindrical body are always held concentrically. Then, it is necessary to secure a predetermined minute gap over the entire circumference so that they do not come into direct contact, and even if it is local,
If the two come into contact with each other and become in a suctioned state, the cylinder body may become immobile even when the screw shaft is rotated.

However, in the conventional magnetic screw, the cylindrical body is simply fitted around the outer circumference of the screw shaft with a gap.
Since the magnetic screw unit itself does not have a means for holding the screw shaft and the cylinder concentrically with a predetermined gap, when mounting this magnetic screw on a machine tool or other equipment, It must be assembled so that a predetermined minute gap can be secured to the cylindrical body, which requires extremely high processing accuracy and assembly accuracy on the device side.

In addition, even if the accuracy on the device side is improved, in reality, there are variations in shape on the magnetic screw side such as the screw shaft and the cylinder.
Since there are inaccuracies and the like, it is very difficult to manufacture them considering all of them. In view of the above conventional problems, the present invention can reliably hold the shaft and the cylindrical body in a non-contact state with a simple structure, and the gap between the shaft and the cylindrical body can be a minute gap,
An object of the present invention is to provide a magnetic screw capable of smoothly and surely converting one rotational or linear movement into the other linear or rotational movement by the magnetic action of magnetic poles.

[0010]

According to a first aspect of the present invention, a shaft and a cylindrical body fitted around the outer periphery of the shaft with a gap therebetween are made of a magnetic material. A magnetic screw provided with a magnetic pole in a spiral shape on at least one of the guides for guiding the shaft on both sides of the tubular body in the axial direction in a substantially concentric manner with respect to the tubular body to guide the shaft in a slidable manner. It is provided with a ring.

According to a second aspect of the present invention, in the first aspect of the invention, a material having wear resistance and slipperiness is used for each of the guide rings.

According to a third aspect of the present invention, in the invention according to the first or second aspect, a spiral groove is formed in the shaft, and at least one of the guide rings is slidably fitted in the spiral groove. The magnetic screw according to claim 1 or 2, further comprising a protrusion for preventing step-out which is fitted thereto.

The present invention according to claim 4 provides the invention according to claims 1 and 2.
Or in the invention described in 3, the screw is provided on the outer periphery of the shaft, the inner peripheral surface of the cylindrical body is configured to be smooth, and the inner peripheral surface side of the cylindrical body is magnetized corresponding to the screw thread. It was made.

The present invention according to claim 5 provides the following:
In the invention described in 2, 3, or 4, 2 is provided on the outer circumference of the shaft.
Threads are provided, and the north pole and the south pole are provided on the inner peripheral side of the cylindrical body so that the N pole corresponds to one of the two threads and the S pole corresponds to the other thread. It is a thing.

[0015]

According to the first aspect of the present invention, the shaft and the cylinder are held concentrically by the guide rings on both sides of the cylinder, and the two are kept in a non-contact state with a minute gap. During operation, the guide rings slidably guide the shaft while keeping them in a non-contact state with a minute gap.

According to the second aspect of the present invention, a material having wear resistance and slipperiness is used for each of the guide rings, which ensures durability of the guide rings and slidability of the shaft. Dust is suppressed or prevented from entering the cylinder.

According to a third aspect of the present invention, a spiral groove is formed in the shaft, and a step-out prevention projection provided on at least one of the guide rings is slidably fitted in the spiral groove. The step-out between the shaft and the cylinder due to an excessive load is prevented.

According to a fourth aspect of the present invention, a screw thread is provided on the outer periphery of the shaft, the inner peripheral surface of the cylindrical body is made smooth, and the inner peripheral surface side of the cylindrical body is formed into the screw thread. Since the magnets are magnetized correspondingly, the structure is simple and the manufacture is easy, and adhesion of magnetic powder or the like to the shaft can be prevented.

According to a fifth aspect of the present invention, the two threads on the outer circumference of the shaft correspond to the N pole and the S pole provided on the inner circumference side of the cylindrical body. A magnetic circuit is formed between them. Therefore, the magnetic force of each magnetic pole on the cylinder side effectively acts on the screw thread on the shaft side.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 and 2 illustrate a first embodiment of a magnetic screw according to the present invention. As shown in FIG. 1, this magnetic screw includes a screw shaft 1, a cylindrical body 2 fitted around the outer periphery of the screw shaft 1, and a pair of guides provided on both sides of the cylindrical body 2 in the axial direction. Rings 3 and 4, cylinder 2 and guide rings 3 and 4
And a housing 5 for holding.

The housing 5 is made of a stainless material or the like in a tubular shape, and a mounting flange 6 is integrally formed on the outer periphery of the housing 5 at one end side in the axial direction. Inside the housing 5, a cylindrical body fitting recess 7 is formed on the center side in the axial direction, a female screw hole 8 is formed at one end of the cylindrical body fitting recess 7, and a partition wall 9 is formed at the other end. The guide fitting recesses 10 are respectively formed therethrough.

A tubular body 2 is fitted in the tubular body fitting concave portion 7, and the tubular body 2 is fixed by a partition wall portion 9 and a nut 11 which is detachably screwed into the female screw hole 8. 2 cylinders for nut 11
A guide fitting recess 13 is formed on the side so that a partition 12 corresponding to the partition 9 is formed. The guide rings 3 and 4 are fitted concentrically with the tubular body 2 into the nut 11 and the guide fitting recesses 13 and 10 of the housing 5, respectively.
5 is detachably fixed to the partition walls 12 and 9 from the outside in the axial direction.

The screw shaft 1 is made of a magnetic material such as an iron-based metal material or a manganese-aluminum magnetic material containing manganese, aluminum, carbon, etc. as its main components. The two threads 16 and 17 are formed in a spiral shape. The threads 16 and 17 are formed in a square cross section.

The cylindrical body 2 is made of a magnetic material such as an iron-based metal material or a rare earth magnetic material in a cylindrical shape, and the inner peripheral surface of the cylindrical body 2 has a smooth shape with the same diameter over the entire length in the axial direction. Is formed in. Then, as shown in FIG. 2, the magnetic poles 1 of the N pole 18 and the S pole 19 are arranged in the axial direction on the inner circumference of the cylindrical body 2.
It is spirally magnetized so that 8,19 can be alternated at regular intervals. Each N pole 18 and S pole 19 are each screw thread of the screw shaft 1.
Corresponding to 16 and 17, respectively, they are continuously provided in a spiral shape with the same lead angle and pitch as the screw threads 16 and 17.

The cylindrical body 2 is fitted over the outer circumference of the screw shaft 1 and has a small gap between the magnetic poles 18 and 19 on the inner circumference and the threads 16 and 17 on the outer circumference of the screw shaft 1. The guide rings 3 and 4 on both sides of the body 2 are held concentrically with the screw shaft 1 in a non-contact state. Therefore, the cylindrical body 2 and the screw shaft 1 are relatively movable in the axial direction and the circumferential direction.

The N pole 18 of the cylinder 2 is attached to the screw thread 16 of the screw shaft 1,
The S poles 19 correspond to the threads 17 of the screw shaft 1, respectively. Between the screw shaft 1 side and the cylinder body 2 side, the spiral poles 18 and 19 are covered over the entire range. 2 N pole 18 to screw shaft 1 thread
A closed loop magnetic circuit following the S pole 19 of the cylinder 2 through the screw thread 17 and the thread 17 is formed respectively, and the N pole 18 and the S pole 19 of the cylinder 2 side are formed.
Due to the magnetic force of, the screw shaft 1 is attracted to the outside all around.

Each of the guide rings 3 and 4 is made of a non-magnetic material such as a synthetic resin material having wear resistance and slipperiness such as MC nylon and Delrin.
The screw shaft 1 is inserted into 3 and 4 so as to be slidable in the axial direction and the circumferential direction. When this magnetic screw is incorporated into a feeder of a machine tool or the like, for example, the screw shaft 1 is interlocked with a drive source such as a motor, and the flange 6 of the housing 5 is fixed to a slide base or the like.

The screw shaft is driven by a drive source such as a motor.
When 1 is rotated in the forward or reverse direction around the axis,
The magnetic force between the N pole 18 and the S pole 19 on the 2 side is the thread 16,1 of the screw shaft 1.
Since it acts on 7, the cylindrical body 2 moves in the axial direction with the rotation of the screw shaft 1 due to the magnetic force, and the slide base can be moved in the axial direction. At this time, the guide rings 3 and 4 slide on the outer circumference of the screw shaft 1 to
The cylindrical body (2) is guided along the screw shaft (1) in the axial direction while keeping and in a non-contact state with a small gap.

That is, the spiral N pole 18 and S pole 19 on the cylinder 2 side
And the magnetic force of
The magnetic force acts on the top surface of 16,17 from the outside through a small gap, and an attractive force acts between the magnetic poles 18,19 on the cylinder 2 side and the threads 16,17 of the screw shaft 1. The action causes the screw shaft 1 to be constrained in the axial direction.

Then, the screw shaft 1 is rotated to rotate the threads 16,17.
When is rotated in the circumferential direction, the magnetic poles 18 and 19 on the cylindrical body 2 side corresponding to the screw threads 16 and 17 try to follow the rotation,
Move in the axial direction according to the lead angle of the threads 16,17.
For this reason, there is a minute gap between the screw shaft 1 side and the cylindrical body 2 side, and both magnetic poles 18
Using the magnetic force of 9 to rotate the screw shaft 1
Can be converted into a linear motion.

This magnetic screw has the following advantages. In this magnetic screw, the screw shaft 1 and the cylindrical body 2 are held in a non-contact state, and there is no mechanical contact between them, so that all the problems caused by conventional frictional resistance can be solved. That is, since the screw shaft 1 and the cylindrical body 2 are held in a non-contact state and the magnetic force of each magnetic pole 18, 19 on the inner peripheral side of the cylindrical body 2 is used, the conventional friction machine is used. It can be used semi-permanently in a high-precision state without deterioration in accuracy and durability.

Since both the screw shaft 1 and the cylindrical body 2 are in non-contact with each other, there is essentially no need for lubrication, and long-term use without lubrication is possible. There is an advantage that all environmental pollution and noise problems due to vibration can be prevented. Therefore, it is very effective for use in places where lubricants, abrasion powder, etc. are disliked.

Further, in holding the screw shaft 1 and the tubular body 2 in a non-contact state, the guide rings 3, 4 are provided on both sides of the tubular body 2.
With the guide rings 3 and 4, the screw shaft 1
Since they are held concentrically and guided slidably, it is possible to reliably prevent contact between the screw shaft 1 and the cylindrical body 2, and to keep a constant small gap between them in a non-contact state. Can be held.

Further, the tubular body 2 and the guide rings 3 and 4 are fitted into the housing 5, and the guide rings 3 and 4 are used to fit the screw shaft.
Since 1 and the cylindrical body 2 are concentrically held with a slight gap, the entire magnetic screw can be handled as one unit, and it is very easy to handle when incorporating it in a feeder or the like.

In particular, when the magnetic screw is installed in a machine tool or the like, it is not necessary to hold the screw shaft 1 and the cylindrical body 2 concentrically on the device side to secure a minute gap. It is not necessary to pay attention to the gap between the screw shaft 1 and the cylinder 2, and it suffices to assemble it so that the magnetic screw side does not get twisted. The mechanism is simplified, and its precision is not particularly required.

Further, the guide shafts 3 and 4 are used to connect the screw shaft 1 and the tubular body.
2 has a structure that holds it in a non-contact state.
It is possible to make the gap between the cylinder 2 and the cylindrical body 2 a minimum minute gap. For this reason, the magnetic poles 18 and 19 of the cylinder 2 and the screw shaft
The magnetic force between the screw threads 16 and 17 of 1 becomes large, and the torque transmitted from the screw shaft 1 to the cylinder body 2 side can be increased.

Moreover, since the screw shaft 1 and the cylindrical body 2 can be securely held in the non-contact state by the guide rings 3 and 4, the screw shaft 1
Since the threads 16 and 17 of No. 3 do not directly contact the magnetic poles 18 and 19 of the cylinder 2, the cylinder 2 can be reliably moved in the axial direction in conjunction with the rotation of the screw shaft 1. Contact with the cylinder
There is no possibility that the 2 will be incapacitated.

Each of the guide rings 3 and 4 holds the screw shaft 1 and guides it in a slidable manner. The threads 16 and 17 of the screw shaft 1 are spirally continuous, and the guide rings 3 and 4 are MC nylon. , Each of the guide rings 3, 4 since they are made of non-magnetic material such as synthetic resin material having abrasion resistance and slipperiness such as Delrin.
With this, the screw shaft 1 can be smoothly guided, and the durability of the guide rings 3 and 4 can be sufficiently ensured. Since each guide ring 3, 4 is made of a non-magnetic material such as a synthetic resin material, the guide rings 3, 4
The magnetic flux does not pass through the side, and the guide rings 3 and 4 can prevent dust such as iron powder from entering the cylindrical body 2 side.

Since the guide rings 3 and 4 are fitted in the guide fitting recesses 13 and 10 of the housing 5 and are detachably fixed with screws 14 and 15, when the inner circumference side is worn due to long-term use. It can be easily replaced by removing the screws 14 and 15. Since the inner circumference of the cylindrical body 2 is made smooth and the inner circumference side is magnetized to provide the N pole 18 and the S pole 19 in a spiral shape, the magnetic poles 18, 19 are arranged on the cylindrical body 2 side. Despite this, its structure is simple and can be easily manufactured.

Further, each magnetic pole 18, 19 is provided on the cylinder 2 side, the screw shaft 1 is made of a magnetic material, and the same as each spiral magnetic pole 18, 19 on the cylinder 2 side is provided on the outer periphery of this screw shaft 1. Since the threads 16 and 17 are spirally formed with the same lead angle and the same pitch, machining on the screw shaft 1 side can be facilitated and at the same time, other magnetic powder etc. adheres to the surface of the screw shaft 1 from the outside. Nothing.

Moreover, since the magnetic poles 18 and 19 are on the inner circumference of the cylindrical body 2, other magnetic powder or the like does not directly adhere to the magnetic poles 18 and 19 from the outside, and the magnetic poles 18 and 19 on the cylindrical body 2 side. Since most of the magnetic flux of 19 passes through the inside of the screw shaft 1 side, there is almost no leakage magnetic flux leaking from the magnetic poles 18 and 19 to the outside though the magnetic action of the magnetic poles 18 and 19 is utilized. The problem due to the leakage magnetic flux can be made less likely to occur.

Since the magnetic poles 18 and 19 are provided on the cylinder 2 side, the magnetic pole 1 is irrelevant regardless of the stroke when the cylinder 2 makes a linear motion.
The axial range in which 8 and 19 should be provided is determined, and screw shaft 1
The range can be made smaller than when the magnetic poles 18 and 19 are provided on the side.

3 and 4 illustrate a second embodiment of the magnetic screw according to the present invention, in which a step-out preventing projection 20 is spirally provided on the inner circumference of each guide ring 3, 4. . The screw shaft 1 has a semicircular thread groove (spiral groove) between its threads 16 and 17.
22 is formed, and the projection 20 is integrally formed on the inner circumference of the guide rings 3 and 4 so as to slide in the thread groove 22.
The protrusion 20 is formed in a long spiral shape along the spiral direction of the thread groove 22.

As shown in FIG. 4 (A), the protrusions 20 correspond to the two thread grooves 22 on the screw shaft 1 side, respectively.
It may be provided with a thread, or as shown in FIG.
One thread may be provided corresponding to either one of the two thread grooves 22 on the one side. In this embodiment, since the step-out prevention projection 20 is provided spirally on each guide ring 3 and 4, even if an excessive load is temporarily applied in the thrust direction, the projection 20 causes the screw shaft to move. The step-out phenomenon between 1 and the cylinder 2 can be prevented. Therefore, with the threads 16 and 17 of the screw shaft 1 and the magnetic poles 18 and 19 of the cylinder 2 always corresponding,
It is possible to smoothly and reliably transmit the torque from 1 to the cylindrical body 2.

Moreover, since the protrusion 20 has a spiral shape, damage to the protrusion 20 can be prevented as much as possible, and the durability is improved. In addition, although the protrusion 20 has a spiral shape, the guide ring
When 3, 4 are made of synthetic resin, they can be easily integrally molded at the time of molding. In the second embodiment, the projections 20 are provided on the respective guide rings 3 and 4, but they may be provided on either one of the guide rings 3 and 4.

FIG. 5 illustrates the third embodiment of the magnetic screw according to the present invention, in which the step-out prevention projection 20 is formed by a pin. That is, the protrusion 20 is composed of a pin having a spherical tip, and after the guide ring 4 is fitted into the guide fitting recess 10 of the housing 5, the protrusion 20 is inserted into the guide ring 4 from the outside of the housing 5. Then, the spherical portion at the tip thereof is fitted into the screw groove 22.

The step-out prevention projection 20 is thus formed by the pin 31.
You may comprise by. In this case, the protrusion 20 and the thread groove
Since the contact area with 22 can be reduced, the increase in frictional resistance due to the protrusion 20 can be prevented, and the pin 21 can be attached to the housing 5.
Since it penetrates through the guide ring 4 and the guide ring 4, the guide ring 4 can be fixed by this pin 21, and the screws 14 and 15 of the first embodiment can be omitted.

FIG. 6 illustrates a fourth embodiment of the present invention, in which a shaft 23 having no threads on its outer periphery is used, and the outer peripheral side of this shaft 23 is magnetized to provide the N pole 18 and the S pole of the cylindrical body 2. S pole 24 and N corresponding to 19
The pole 25 is provided in a spiral shape, the step-prevention spiral groove 26 is provided, and the step-out prevention projection 20 slidably fitted in the spiral groove 26 is provided on the inner circumference of each guide ring 3, 4. It is provided.

In this embodiment, the magnetic poles 24 and 25 of the shaft 23 and the cylindrical body
Since the different poles of the second magnetic pole 18 and 19 correspond to the inside and outside, a large attractive force acts between the magnetic poles 18 and 19 and the magnetic poles 24 and 25, and the shaft 23 and the cylindrical body 2 There is an advantage that the magnetic restraining force in the axial direction of and can be made very large. In particular, a large attractive force acts between the magnetic poles 18,19 and the magnetic poles 24,25 over the entire length of the magnetic poles 18,19 on the cylindrical body 2 side in the spiral direction. The torque can be increased. Further, since the spiral groove 26 is formed on the shaft 23 side and the projection 20 is fitted into this, the step-out between the shaft 23 and the cylindrical body 2 can be prevented.

FIG. 7 illustrates a fourth embodiment of the magnetic screw according to the present invention. 7 (A) shows a cylindrical body on the outer periphery of the screw shaft 1 side.
Trapezoidal thread 16 corresponding to N pole 18 and S pole 19 of 2 respectively
And a thread 17 are formed respectively, and a V-shaped thread groove 22 is provided between the threads 16 and 17. 7B shows the screw shaft 1
A trapezoidal thread 16 and a thread 17 corresponding to the N pole 18 and the S pole 19 of the cylinder 2 are formed on the outer periphery of the side, respectively.
A V-shaped inverted trapezoidal thread groove 22 is provided between 6 and 17.

Also in these cases, the same effects as those of the above-mentioned respective embodiments can be obtained. Moreover, screw thread 1 of screw shaft 1
6,17 has a trapezoidal shape and its wide top surface is a cylinder 2
Since it corresponds to the N pole 18 and the S pole 19 on the side, the magnetic fluxes of the N pole 18 and the S pole 19 pass perpendicularly to the top surface of the screw thread 16,
A magnetically coupled state can be sufficiently obtained. The threads 16 and 17 have a trapezoidal shape or a shape close to it, and the guide rings 3 and 4 at both ends of the tubular body 2 slide on the top surface of the threads. It is also possible to reduce the damage on the inner peripheral surface of 4, 4.

8 to 10 illustrate a fifth embodiment of the magnetic screw according to the present invention, in which guide rings are provided on both the left and right sides of the cylindrical body 2.
The magnetic poles 27 and 28 of the N pole 27 and the S pole 28 are provided on the outer circumference of the round rod-shaped smooth shaft 32, and the magnetic poles 27 and 28 of the cylindrical body 2 are internally threaded with a magnetic body. It is what

As shown in FIGS. 8 and 9, the outer circumference of the shaft 32 is directly magnetized on the outer circumference so that the N pole 27 and the S pole are formed.
The pole 28 and the spiral are provided. Guide rings 3 and 4 are removably mounted on both sides of the cylinder 2 with screws or the like, and as shown in FIGS. A trapezoidal thread 29 and a trapezoidal, V-shaped or semicircular thread groove 30 are formed.

The thread 29 has the same lead angle and pitch as the magnetic poles 27, 28 of the shaft 32. Further, a housing may be provided on the outer circumference of the cylindrical body 2 and the guide rings 3 and 4. In the magnetic screw of this embodiment, each magnetic pole 27, 28 is provided on the smooth outer periphery of the shaft 32.
Threads 29 are provided on the smooth inner circumference of the cylindrical body 2, respectively, and the inside and outside of the first embodiment and the like have a reverse structure. But the screw shaft 32
Side S pole 28 magnetic force acts on the thread 29 on the cylinder 2 side,
Since 26 is restrained in the axial direction, the rotational movement of the shaft 32 can be converted into the linear movement of the cylindrical body 2.

In this embodiment, the thread 29 is formed on the inner circumference of the cylindrical body 2.
Therefore, the protection is easy. Further, since the round rod-shaped shaft 32 having no threads or grooves is used, the guide rings 3 and 4 are less damaged as compared with the first embodiment, and other magnetic powder, dust, etc. Even if it adheres, its cleaning is very easy. The N pole 27 of the pair of magnetic poles 27, 28 of the shaft 32 may correspond to the screw thread 29 of the cylindrical body 2.

FIG. 11 illustrates a sixth embodiment of the magnetic screw according to the present invention, in which both the outer circumference of the shaft 32 and the inner circumference of the cylinder 2 are made smooth, and the outer circumference of the shaft 32 and the cylinder 2 are formed. Magnetic poles 27, 28, 18 and 19 are provided on both the inner circumference and the inner circumference, respectively. Also in this embodiment, since the outer circumference of the shaft 32 is smooth, each guide ring
The damage of 3,4 can be reduced.

FIG. 12 illustrates a seventh embodiment of the magnetic screw according to the present invention, in which the repulsive force of magnetic force is utilized. That is, as shown in FIG.
And as shown in (B), trapezoidal or mountain-shaped thread 1
6,29 and thread grooves 22,30 are formed respectively, and their respective threads 1
6,29 mesh with a small gap.
The magnetic poles 27,28 are magnetized so that the N poles 27,18 and the S poles 28,19 are formed on both ends in the axial direction of the screw shaft 1 at the tips of the screw threads 16,29. 18,19 are provided and its screw shaft
The magnetic poles 27 and 28 on the first side and the magnetic poles 18 and 19 on the cylindrical body 2 are arranged so that the same poles face each other and repel each other.

Also in this embodiment, between the magnetic poles 27, 28, 18 and 19 on the screw shaft 1 side and the cylindrical body 2 side, that is, the N pole 27, the N pole 18 and the S pole.
The magnetic force between 28 and the S pole 19 acts as a repulsive force, and the screw shaft 1 and the cylindrical body 2 are constrained by the repulsive force in the axial direction in a non-contact state.

Moreover, the screw shaft 1 and the cylindrical body 2 are provided with screw threads 16, 2
9 are formed respectively, and these threads 16 and 29 are magnetized, so that they can be easily magnetized and the magnetic poles 27, 28, 18 and 19 are effective by increasing the height of the threads 16 and 29. There is an advantage that a large area can be taken and the magnetic force between the magnetic poles 18 and 19 can be increased to surely restrain magnetically. Further, since the screw threads 16 and 29 of the screw shaft 1 and the cylindrical body 2 are meshed with each other with a minute gap, it is possible to prevent step-out due to excessive load.

Although the respective embodiments have been described in detail above, the present invention is not limited to the respective embodiments. For example, a protective cylinder made of a non-magnetic material or a weak magnetic material is used, and a small-diameter cylindrical body 2 made of a ferromagnetic material is fitted to the inner circumference of the protective cylinder to magnetize it, or the N pole 18 and A single unit of a permanent magnet having the S pole 19 may be spirally fitted and mounted on the inner circumference of the protective cylinder.

In addition, a strip-shaped magnetic body is formed into a spiral shape,
After magnetizing so that the N pole 18 and the S pole 19 are formed on both sides in the width direction, the spiral magnetic body is press-fitted into the cylindrical body 2, or the spiral magnetic body is molded for the cylindrical body. It may be put in the mold and molded into a cylinder with a synthetic resin material. When the synthetic resin material is used for the tubular body 2 in this way, the tubular body 2 and the guide rings 3 and 4 may be integrally formed.

Further, in each of the embodiments, the case where the rotational movement of the screw shaft 1 or the like is converted into the linear movement of the cylindrical body 2 has been described, but the screw shaft 1 or the like is provided movably in the axial direction and If the body 2 is rotatably provided, it is possible to convert the rotational movement of the tubular body 2 into a linear movement of the screw shaft 1 or the like.

If the lead angle is increased, the linear motion of the screw shaft 1 or the cylinder 2 can be converted into the rotational motion of the cylinder 2 or the screw shaft 1. The magnetic poles 27, 28, 18, 19 may be partially provided at one place, or may be intermittently provided at a predetermined lead angle in the spiral direction, and are not necessarily provided continuously in the spiral direction. Further, when the magnetic pole is provided on the cylindrical body 2, an electromagnet may be used.

[0064]

According to the present invention as set forth in claim 1, the shaft and the cylindrical body fitted around the outer periphery of the shaft with a gap therebetween are made of a magnetic material, and the shaft and the cylindrical body are connected to each other. In a magnetic screw provided with a magnetic pole in a spiral shape on at least one side, guide rings for holding the shaft substantially concentrically with respect to the cylindrical body and slidably guiding the shaft are provided on both sides in the axial direction of the cylindrical body. Since it is provided, the shaft and the cylinder can be securely held in a non-contact state with a simple structure, and the gap between the front shaft and the cylinder can be made a minute gap. Alternatively, the linear motion can be smoothly and surely converted into the other linear or rotary motion, and the device can be easily assembled to another device or the like.

According to the present invention of claim 2, in the invention of claim 1, since each guide ring is made of a material having wear resistance and slipperiness, durability of the guide ring is improved. In addition, the slidability of the shaft can be ensured, and dust and the like can be suppressed or prevented from entering the cylindrical body.

According to the present invention of claim 3, in the invention of claim 1 or 2, a spiral groove is formed in the shaft, and at least one of the guide rings is slidable in the spiral groove. Since the step-out preventing projection that fits into the shaft is provided, it is possible to ensure smooth and reliable operation without step-out between the shaft and the cylinder due to an excessive load.

According to the invention described in claim 4, in the invention described in claim 1, 2 or 3, a screw thread is provided on the outer periphery of the shaft, and the inner peripheral surface of the cylindrical body is configured to be smooth. However, since the inner peripheral surface side of the cylindrical body is magnetized in correspondence with the threads, the structure is simple and the manufacture is easy, and magnetic powder and the like can be prevented from adhering to the shaft.

According to the invention described in claim 5, in the invention described in claim 1, 2, 3, 4 or 5, two threads are provided on the outer circumference of the shaft, and the two threads are provided. N on one side of the mountain
Since the pole is provided with the N pole and the S pole on the inner peripheral side of the cylindrical body so that the S pole corresponds to the other screw thread, the magnetic force of each magnetic pole on the cylindrical side is on the axial side. It effectively acts on the threads, and with a simple structure, it is possible to reduce the leakage magnetic flux and secure a sufficient torque.

[Brief description of drawings]

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

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a partially cutaway front view showing a second embodiment of the magnetic screw according to the present invention.

FIG. 4 is a sectional view showing a second embodiment of the magnetic screw according to the present invention.

FIG. 5 is an enlarged sectional view of a guide ring showing a third embodiment of the magnetic screw according to the present invention.

FIG. 6 is a sectional view showing a fourth embodiment of the magnetic screw according to the present invention.

FIG. 7 is an enlarged cross-sectional view of an essential part showing a fifth embodiment of the magnetic screw according to the present invention.

FIG. 8 is a partially cutaway front view showing a sixth embodiment of the magnetic screw according to the present invention.

FIG. 9 is a front view of a shaft showing a sixth embodiment of the magnetic screw according to the present invention.

FIG. 10 is an enlarged cross-sectional view of essential parts showing a sixth embodiment of the magnetic screw according to the present invention.

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

FIG. 12 is an enlarged cross-sectional view of a main part showing a seventh embodiment of the magnetic screw according to the present invention.

[Explanation of symbols]

 1 Screw shaft 2 Cylindrical body 3,4 Guide ring 5 Housing 9,12 Partition wall part 10,13 Guide fitting recess 16,17 Thread 18,27 N pole 19,28 S pole 20 Protrusion 22 Thread groove (spiral groove) 23 Axis 26 spiral groove

Claims (5)

[Claims] 1. A magnetic screw comprising a shaft and a cylindrical body fitted around the outer periphery of the shaft with a gap made of a magnetic material, and at least one of the shaft and the cylindrical body being provided with a magnetic pole in a spiral shape. 2. A magnetic screw, characterized in that guide rings are provided on both sides in the axial direction of the tubular body so as to slidably guide the shaft in a substantially concentric manner with respect to the tubular body. 2. The magnetic screw according to claim 1, wherein a material having wear resistance and slipperiness is used for each of the guide rings. 3. A step for preventing step-out is formed in the shaft by forming a spiral groove, and at least one of the guide rings is provided with a step-out preventing projection slidably fitted in the spiral groove. Or the magnetic screw according to 2. 4. A screw thread is provided on the outer circumference of the shaft, the inner peripheral surface of the cylindrical body is configured to be smooth, and the inner peripheral surface side of the cylindrical body is magnetized corresponding to the screw thread. Claim 1, characterized in that
The magnetic screw according to 2 or 3. 5. The inside of the cylindrical body is provided with two threads on the outer circumference of the shaft so that the N pole corresponds to one of the threads of the two threads and the S pole corresponds to the other thread. The magnetic screw according to claim 1, 2, 3 or 4, wherein an N pole and an S pole are provided on the circumferential side.