JPH0325743Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a rotary hook for a sewing machine, and more particularly to a structure for eliminating the adverse effects caused by rotational friction between the outer hook and the inner hook of the rotary hook.

Conventional technology In a conventional vertical full-rotation hook, in which the outer hook is rotated with the inner hook inserted into the outer hook raceway, the outer hook and the inner hook are made of iron. The rotation speed of the outer hook is at most 7000RPM
It is. In a structure in which lubricating oil is supplied to the outer hook raceway and the inner hook raceway, the rotational speed of the outer hook is 12,000 RPM at most. In such prior art, although the lubricating oil reduces the sliding resistance, wear of the outer hook raceway and the inner hook raceway occurs. The use of this lubricating oil causes oil to adhere to the thread, making it impossible to proceed with the sewing operation smoothly.

Problems to be Solved by the Invention The purpose of the invention is to provide an improved rotary hook that reduces slip resistance, enables high-speed rotation of the outer hook, and prevents the yarn from being contaminated by lubricating oil. It is to be.

Means for Solving the Problems According to the present invention, a protrusion 11 is formed on the outer circumferential surface of the inner pot 3 and protrudes outward in the radial direction and extends in the circumferential direction. The rail 5 includes a pair of first and second permanent magnet pieces 12 and 14 fixed to both sides of the inner hook 3 in the axial direction, and a third permanent magnet piece 13 fixed to the outer peripheral surface of the protrusion 11. However, on the inner circumferential surface of the outer hook 2, there is a first groove 20 that is recessed outward in the radial direction and extends in the circumferential direction;
A second groove 21 is formed which is further recessed outward in the radial direction than the first groove 20 and extends in the circumferential direction.
A pair of fourth and fifth permanent magnet pieces 8, 10 are fixed to the first and second permanent magnet pieces 12, 14, respectively, facing each other at intervals d1, d3.
A sixth permanent magnet piece 9 facing the third permanent magnet piece 13 at a distance d2 is fixed to the second groove 21 to form a rail 6, and the first, second, and third permanent magnet pieces 1
The rotary hook is characterized in that the permanent magnet pieces 2, 14, 13 and the fourth, fifth, and sixth permanent magnet pieces 8, 10, 9 are magnetized so as to mutually generate magnetic repulsion.

Effect According to the present invention, the first to third permanent magnet pieces and the fourth
~The sixth permanent magnet pieces are arranged facing each other with the rails fitted into the track grooves, and each permanent magnet piece is magnetized so as to mutually generate magnetic repulsion, so the sixth permanent magnet pieces are The first permanent magnet piece and the second permanent magnet piece are spaced apart from each other. This prevents the outer hook raceway and the inner hook rail from coming into contact with each other due to magnetic repulsion, thereby significantly reducing slip resistance and allowing the outer hook to move at high speeds. For example, it is possible to rotate at 20,000 RPM. Furthermore, since the lubricating oil mentioned in connection with the prior art mentioned above is not used in the present invention, problems such as thread staining due to this lubricating oil are solved, and sewing work can proceed smoothly. It becomes like this.

Embodiment FIG. 1 is a sectional view of a vertical full-rotation hook 1 according to an embodiment of the present invention. An inner hook 3 is housed in the outer hook 2, and a bobbin 4 for winding a bobbin thread is attached to the inner hook 3. The inner hook 3 is an inner hook rotation prevention member (not shown) fixed to the body of the sewing machine.
Its rotation is restrained by. Inner pot 3
A rail 5 is formed in the shape of an outward flange on the outer peripheral surface of the shoulder. This rail 5 fits into a rail groove 6 formed on the inner circumferential surface of the outer hook 2. The outer hook 2 is rotationally driven in one direction around its axis by a driving means connected to its rotating shaft 7.

FIG. 2 is an enlarged sectional view of the vicinity of the section in FIG. 1. The outer hook 2 is made of materials such as iron and aluminum, and a first groove 20 is formed on the inner circumferential surface of the outer hook 2 and is recessed outward in the radial direction and extends in the circumferential direction. Another second groove 21 is formed further radially outward than the groove 20. The third to sixth permanent magnet pieces 8, 9, 10 are fixed to these grooves 20, 21, as shown in a perspective view in FIG. The inner surfaces of these permanent magnet pieces 8, 9, and 10 constitute the track groove 6. As mentioned above, the outer hook 2 is made of materials such as iron and aluminum,
Therefore, it becomes possible to have sufficient strength and is prevented from deforming due to the centrifugal force generated when rotating at high speed.

The inner hook 3 is made of a material such as synthetic resin, and the rail 5 includes a protrusion 11 that projects radially outward from the outer peripheral surface of the inner hook 3 and extends in the circumferential direction, and an annular ring fixed to the protrusion 11. permanent magnet pieces 12, 13,
14. The first and second permanent magnet pieces 12 and 14 are fixed to both sides in the axial direction of the inner hook with the protrusion 11 in between, and the third permanent magnet piece 13
is fixed to the outer peripheral surface of the protrusion 11. The mutually opposing permanent magnet pieces 8 and 12 have the same opposing magnetic poles, which are north poles in this embodiment. The mutually opposing poles of the permanent magnet pieces 9 and 13 are the same, and in this embodiment are north poles. Further, the opposing magnetic poles of the permanent magnet pieces 10 and 14 are the same, and are N poles in this embodiment. In this way, magnetic repulsion is generated between the track groove 6 and the track 5, and the permanent magnet pieces 8, 12; 9, 13, 10, 1 facing each other
4 are spaced apart at intervals d1, d2, and d3. This allows the outer hook 2 to rotate without the raceway groove 6 and the raceway 5 almost coming into contact with each other.

FIG. 4 is a sectional view of another embodiment of the present invention. In this embodiment, permanent magnet pieces 8a, 9a, and 10a forming the raceways 6 of the outer hook 2 are fixed to the outer hook 2. One permanent magnet piece 13a is fixed to the protrusion 11 of the inner rotor 3, and thereby the rail 5
is configured. The magnetic pole of the permanent magnet piece 13a has the same polarity as the magnetic pole facing the permanent magnet piece 13a of the permanent magnet pieces 8a, 9a, and 10a. Therefore, magnetic repulsion between the track groove 6 and the track 5 is exerted. The other configurations are similar to those of the previous embodiment.

FIG. 5 is a sectional view of yet another embodiment of the present invention. Although this embodiment is similar to the embodiment shown in FIG. 4, it should be noted that the protrusion 11 of the inner hook 3
A mounting hole 15 is formed in the mounting hole 1.
5 is fixed with a permanent magnet piece 13a fitted therein.
The permanent magnet pieces 8a, 9a, 10a are formed in an arcuate shape, as described in connection with FIG. 3 above. The permanent magnet pieces 13b are rod-shaped and extend in the axial direction of the inner hook 3 (vertical direction in FIG. 5), and are arranged at intervals in the circumferential direction of the inner hook 3. With such a configuration, a magnetic repulsion force between the rail groove 6 and the rail 5 is also generated.

FIG. 6 is a perspective view of a portion of another embodiment of the present invention. In this embodiment, permanent magnet pieces 8b, 9b, and 10b are embedded within the outer hook 2. The permanent magnet piece 13b attached to the inner hook 3 is the fifth
Similar to the illustrated embodiment. In such an embodiment, the permanent magnet piece 13b and the permanent magnet piece 8
Mutual frictional contact can be suppressed by magnetic repulsion with b, 9b, and 10b.

The present invention can be implemented not only in connection with a vertical full-rotation hook, but also in connection with a horizontal full-rotation hook. Furthermore, it can also be implemented in conjunction with a half-rotary hook.

Effects of the invention As described above, according to the invention, the first to third permanent magnet pieces and the fourth to sixth permanent magnet pieces, which are magnetized so as to mutually generate magnetic repulsion, are provided facing each other. Therefore, the rail and the track groove are separated by the magnetic repulsion, which makes it possible to significantly reduce the frictional resistance between the outer hook and the inner hook during sewing. This makes it possible to reduce wear as much as possible. Moreover, since the friction between the rail and the rail groove is reduced, the outer hook can be rotated at high speed, thereby increasing the sewing speed. Moreover, since the friction between the rail and the rail groove is reduced, there is no need to supply lubricating oil between the rail and the rail groove, and it is possible to prevent the yarn from being contaminated by the lubricating oil.

In addition, since the first to third permanent magnet pieces are fixed to the protrusion of the inner hook to form a rail, the rail formed on the existing inner hook can be polished using a polishing device or the like. The protrusion can be formed. In addition, since the fourth to sixth permanent magnet pieces are fixed in the first and second grooves of the outer hook to form a raceway groove, for example, a polishing device or the like can be used in the raceway groove of the existing outer hook. A groove can be formed. Therefore, it is possible to implement the present invention using existing inner and outer hooks, and therefore the present invention can be implemented at low cost and over a wide range of areas.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is an enlarged sectional view of the section in FIG. 1, and FIG. 3 is an exploded view of a portion of the embodiment shown in FIGS. 1 and 2. A perspective view, FIG. 4 is a sectional view of another embodiment of the present invention,
FIG. 5 is a sectional view of still another embodiment of the present invention, and FIG. 6 is a perspective view of a portion of another embodiment of the present invention. 1... Vertical full rotation hook, 2... Outer hook, 3...
Inner hook, 4...Bobbin case, 5...Rail, 6...
...Rail groove, 8, 8b, 9, 9a, 9b, 10, 10
a, 10b, 12, 13, 13a, 13b, 14
... Permanent magnet piece, 11 ... Protrusion, 20, 21 ...
Concave groove.

Claims (1)

[Claims for Utility Model Registration] A protrusion 11 that protrudes outward in the radial direction and extends in the circumferential direction is formed on the outer circumferential surface of the inner hook 3. The rail 5 includes a pair of first and second permanent magnet pieces 12 and 14 fixed to both sides in the axial direction, and a third permanent magnet piece 13 fixed to the outer peripheral surface of the protrusion 11. The inner peripheral surface of the rotary hook 2 includes a first groove 20 that is recessed outward in the radial direction and extends in the circumferential direction;
A second groove 21 is formed which is further recessed outward in the radial direction than the first groove 20 and extends in the circumferential direction.
A pair of fourth and fifth permanent magnet pieces 8, 10 are fixed to the first and second permanent magnet pieces 12, 14, respectively, facing each other at intervals d1, d3.
A sixth permanent magnet piece 9 facing the third permanent magnet piece 13 at a distance d2 is fixed to the second groove 21 to form a rail 6, and the first, second and third permanent magnet pieces 1
2, 14, 13 and the fourth, fifth, and sixth permanent magnet pieces 8, 10, 9 are magnetized so as to mutually generate magnetic repulsion.