JPH0928961A - Total rotation shuttle of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a total rotation shuttle which can be adapted to a high speed rotation of a sewing machine without feeding a lubricant, and in addition, which can totally eliminate the staining of a thread. SOLUTION: At least a track belt 17 of a rotating hook bobbin case holder 16 is formed of a heat resistant resin material, and at least on the surface of a track belt groove 14 of a rotating hook 5, a film 40 of a diamond like carbon is formed, to reduce a sliding resistance between the rotating hook 5 and the rotating hook bobbin case holder 16, and by this method, a total rotation shuttle can be adapted to a high speed rotation of a sewing machine without staining a thread.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full rotary hook of a sewing machine in which an outer hook is supported on an end portion of a lower shaft of a sewing machine, and an inner hook is housed inside the outer hook so as to be relatively rotatable. In particular, it relates to a full rotary hook suitable for an industrial sewing machine having a high rotational speed.

[0002]

2. Description of the Related Art In the above-mentioned industrial sewing machine, the needle reciprocates up to about 5,500 times per minute, so that each position performing an operation related to the operation of this needle rotates up to about 11,000 times. Therefore, unless the lubricating oil is forcibly supplied to the bearings at such high-speed rotating locations by a pump, the members may overheat and seize or wear. By the way,
Generally, it is for hooking the bobbin thread on the needle thread through which the needle is inserted, so the metal inner pot that houses the bobbin wound with the bobbin thread reciprocates the needle. While stationary, the outer hook, which is also made of metal and has a hook for hooking the upper thread, rotates at high speed in association with the reciprocating motion of the needle.

Therefore, conventionally, lubricating oil is also supplied to a substantially annular gage which is a sliding portion of an inner kettle that slides relatively to an approximately annular gage groove formed in the outer kettle. It was

A conventional full rotary hook, which supplies the lubricating oil as described above, will be described with reference to FIG.

In FIG. 5, the sewing machine is provided with a lower shaft 1 which can be rotated at a high speed by a driving means such as a motor (not shown), and the lower shaft 1 is arranged at intervals in the axial direction. It is supported by a thrust bearing 3 incorporated in a pair of metals 2 (only one of which is shown) so that movement in the axial direction is restricted. A first lubricating oil passage 4 that extends in the axial direction is formed along the center of the lower shaft 1. Inside the first lubricating oil passage 4, a base of the lower shaft 1 (not shown) is formed. The lubricating oil can be supplied from the end side.

An outer hook 5 is fixed to the tip of the lower shaft 1. The outer pot 5 has a disc-shaped base 6 fitted to the outer periphery of the tip of the lower shaft 1, and a substantially cylindrical outer pot main body 10 that is connected to the tip of the base 6. The base 6 has a central hole 7 into which the tip of the lower shaft 1 can be inserted relatively densely. Further, the base portion 6 is formed with a radial screw hole 8 that communicates from the outer peripheral surface 6a to the central hole 7, and a screw 9 is screwed into the screw hole 8 so that the tip of the screw 9 is attached. The outer hook 5 can rotate integrally with the lower shaft 1 by being pressed against the outer peripheral surface 1 a of the lower shaft 1.

The outer pot main body 10 is provided with a substrate 11 having a diameter larger than that of the base 6 concentrically provided on the tip of the base 6, and a substantially cylindrical outer peripheral wall 12 connected to the tip of the substrate 11. A relatively thin hook member 13 is attached to the outer peripheral surface 12a of the outer peripheral wall 12 by a screw (not shown). Further, on the inner peripheral surface 12b of the outer peripheral wall 12 of the outer hook 5, a substantially annular guide groove 14 which is a guide groove is formed.

The inner pot storage chamber 1 inside the outer peripheral wall of the outer pot 5.
An inner pot 16 which is rotatable relative to the outer pot 5 is provided in the inside 5. The inner pot 16 is formed in a substantially cylindrical shape as a whole, and the outer peripheral surface 16a of the inner pot 16 is
A rail 17 that fits in the rail groove 14 of the outer hook 5 and is a substantially annular guide protrusion that can slide relatively in the circumferential direction.
Is laid around except for the part where the thread comes out. A support plate 18 is attached integrally to the base end portion of the inner pot 16 in the diametrical direction, and the axial direction of the inner pot 16 is at the center of the support plate 18 in the longitudinal direction. A support pin 19 extending in the axial direction is coaxially projected. This support pin 19
A bobbin (not shown) in which a lower thread is wound is attached to this.

A circular concave portion 20 communicating with the central hole 7 and having a diameter larger than that of the central hole 7 is formed in the substrate 11 of the outer hook main body 10 of the outer hook 5. A second lubricating oil passage 21 that extends inside the shuttle 5 is communicated. The second lubricating oil passage 21 is formed in the substrate 11 so as to extend substantially in the radial direction, and communicates with the radial passage 22 communicating with the circular recess 20 and the outer end of the radial passage 22. And an axial passage 23 formed so as to extend substantially axially from the substrate 11 to the outer peripheral wall 12.

The tip of the axial passage 23 reaches the vicinity of the guide groove 14, and the guide groove 14 and the axial passage 23 are provided in the outer peripheral wall 12 at this portion.
A circular filtration chamber 24 communicating with each of the above is formed. The filtration chamber 24 is open to the outer peripheral surface 12a of the outer peripheral wall 12 and is openably / closably covered by a lid (not shown). A filtration member 25 made of fibers made of felt or the like hardened like a nonwoven fabric is housed in the filtration chamber 24.

On the other hand, at the tip of the lower shaft 1, a holding sleeve 27 holding a filtering member 26 for limiting the amount of oil.
Is to be mounted. This holding sleeve 27
Is a sleeve main body 28 having a threaded portion formed on the outer peripheral surface to be screwed with a threaded portion (not shown) formed on the inner peripheral surface forming the first lubricating oil passage 4 of the lower shaft 1, and the sleeve main body 28.
And a flange 2 that has a diameter larger than that of the first lubricating oil passage 4
9, the flange 29 is formed with a communication hole 30 that communicates the inside of the sleeve body 28 and the circular recess 20. The sleeve body 2
At the inner end of 8, there is formed a recess 31 communicating with the communication hole 30 and having a small-diameter frustoconical shape on the communication hole 30 side.

According to the above-described conventional structure, the lower shaft 1 rotates at a high speed together with the outer hook 5 and the needles (not shown) are sewn in the first lubricating oil passage 4 of the lower shaft 1. The lubricating oil is supplied at a high pressure by a pump (not shown).

By the way, the high-pressure lubricating oil is directly supplied to the outer pot 5.
Although the cloth or the like being sewn will be contaminated with the lubricating oil when sprayed from the guide groove 14 of the above, the filtering member 26 is disposed in the first lubricating oil passage 4, and the filtering member 26 is Due to the resistance of the filtering member 26 when the lubricating oil passes, the lubricating oil passing through the filtering member 26 has its hydraulic pressure and oil amount reduced. Then, when passing through the radial passage 22 of the outer hook main body 10 rotating at a high speed, the lubricating oil is accelerated to some extent by centrifugal force, so that the girth groove 14 of the outer hook 5 is accelerated.
From this, an appropriate amount of lubricating oil is supplied to the rail 17 of the inner pot 16.

[0014]

By the way, as described above, the lubricating oil is applied to the sliding surface of the outer hook 5 and the inner hook 16 (the rail groove 14,
When the frictional resistance is reduced by supplying to the railroad track 17 etc., even if the speed of the lubricating oil is reduced by the filter member 26, there is no possibility that the lubricating oil will be scattered around and the thread will be contaminated with the lubricating oil. I couldn't do that. Especially when dealing with high-speed rotation of the sewing machine, a large amount of lubricating oil is required,
There was a risk that the thread would become contaminated.

The present invention overcomes the above-mentioned problems with the conventional ones, can cope with high-speed rotation of the sewing machine without supplying lubricating oil, and has no thread stains on the sewing machine. The purpose is to provide.

[0016]

The features of the full rotary hook of the sewing machine according to the present invention are that at least the rails of the inner hook are made of a heat-resistant resin material, and the diamond-like surface is formed on at least the surface of the rail groove of the outer hook. -The point is that a carbon film is formed. By adopting such a configuration, the present invention can reduce the sliding resistance between the outer hook and the inner hook without supplying the lubricating oil, and can cope with the high speed rotation of the sewing machine without soiling the thread. You can

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. The same or corresponding components as those of the above-described conventional device are denoted by the same reference numerals in the drawings, and description thereof will be omitted.

1 and 2 show two types of embodiments of an inner pot of a full-rotary pot according to the present invention, and FIGS. 3 and 4 show an embodiment of an outer pot. ing.

In FIG. 1, the inner pot 16 is
It is formed of a heat resistant resin such as liquid crystal polymer type, polyimide type, polyamide imide type, phenol type and polyether ether ketone type.

Further, as shown in FIG. 2, the parts of the inner pot 16 other than the rail 17 are made of normal metal, and only the rail 17 is covered with the liquid crystal polymer, polyimide, polyamideimide, or phenol. Alternatively, it may be formed of a heat-resistant resin such as polyether ether ketone.

On the other hand, in the outer hook 5 shown in FIGS. 3 and 4, the inner peripheral surface 12b of the inner hook storage chamber 15 which is in sliding contact with the inner hook 16 is shown.
Is a diamond with a low coefficient of friction of about 0.2.
A like carbon coating 40 is formed. Further, a diamond-like carbon coating may be formed on the back surface 13b of the hook member 13. The diamond-like carbon coating 40 is formed to a thickness of about 0.1 to 5 μm by plasma CVD, for example.

The diamond-like carbon coating 40 is a hard carbon film which has characteristics similar to diamond in hardness and electrical characteristics, and has a crystallographically amorphous structure. And, its smoothness and lubricity are superior to those of the diamond film. Compositionally, the diamond-like carbon film 40 normally forms an alloy with hydrogen similarly to the amorphous silicon film, and a-C: H
Also described as a membrane. The hydrogen concentration of the diamond-like carbon coating 40 depends on the manufacturing conditions,
It is 40 at%. As described above, the diamond-like carbon film 40 contains a large amount of hydrogen, but becomes softer as the hydrogen content increases to about 50 at%. Therefore, the diamond-like carbon coating 40 may be described as i-C: H.

Next, regarding the electronic structure, carbon in the diamond-like carbon coating 40, which is a hard film, is S.
Mainly bound at p ³ . On the other hand, carbon in the soft film is mainly bonded by Sp ² .

The coefficient of friction between the diamond-like carbon film 40 and the polyimide resin used in the present invention was about 0.1 to 0.13, which was found to be quite small. Further, the amount of wear of the diamond-like carbon coating 40 itself due to friction and the attacking property against the opponent are very small, the releasability is also very excellent, and the non-adhesiveness to the resin is also very good. Because of this feature,
Since the abrasion powder of the resin forming the inner hook 16 does not adhere to the surface of the diamond-like carbon coating 40, the thread slips easily and can pass through the gap between the inner hook 16 and the outer hook 5, eliminating the sewing trouble. can do. The hardness of the diamond-like carbon coating 40 is 200
It has a wear resistance of about 0 to 4000 HV.

According to the above-mentioned structure, the sliding surface of the inner hook 16 is made of resin, and the sliding surface of the outer hook 5 is made of diamond-like carbon. The sliding between the outer pot 5 and the outer pot 5 is sliding between the resin and diamond-like carbon. Therefore, the coefficient of friction between these resins and diamond-like carbon is 0.1 or less, and since diamond-like carbon has a low adhesive property with the resin, not only can seizure be prevented. In addition, wear can be reduced, and heat generation, which is a very important factor in eliminating oil supply, can be suppressed to be small. Furthermore, since the resin and diamond-like carbon have high surface smoothness and the friction coefficient between them is small as described above, the frictional force with the thread is reduced, and the thread tightness during sewing is reduced. Will get better.

As a result, since high-speed rotation can be performed without oil supply, the full-rotary hook of the present invention can be applied to an industrial sewing machine that performs high-speed rotation of 4000 rotations or more, and thread stains caused by lubricating oil can be prevented. No sewing can be done.

The present invention is not limited to the above-described embodiment, but various modifications can be made if necessary. For example, a diamond-like carbon coating may be formed on the outer hook spring to improve thread slippage and improve sewing quality.

[0028]

As described above, according to the present invention, it is possible to cope with the high speed rotation of the sewing machine without supplying the lubricating oil, the thread is not contaminated at all, and the sewing is performed without the trouble of sewing. be able to.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of an inner hook in a full-rotary hook according to the present invention.

FIG. 2 is a vertical cross-sectional view of a main portion showing a second embodiment of an inner hook of a full-rotary hook according to the present invention in a state of being engaged with an outer hook.

FIG. 3 is a front view showing an embodiment of an outer pot in the full-rotary pot of the present invention.

FIG. 4 is a vertical cross-sectional view of essential parts showing an engaged state between the outer hook and the inner hook in FIG.

FIG. 5 is a vertical sectional view of a conventional full rotary hook.

[Explanation of symbols]

 1 Lower shaft 5 Outer kettle 14 Gauge groove 15 Inner kettle storage chamber 16 Gauge 40 Diamond-like carbon coating

Claims (1)

[Claims] 1. An outer hook which is supported by an end portion of a lower shaft which is rotationally driven and has a substantially annular girder groove formed on an inner peripheral surface of an inner hook storage chamber, and a gauge of the outer hook which accommodates a bobbin. A full rotary hook of a sewing machine having an inner hook housed in an inner hook storage chamber of the outer hook so as to be capable of relative rotation with respect to the outer hook, and having a substantially annular railroad band that can slide along the band groove, At least the rail of the inner hook is formed of a heat-resistant resin material, and a diamond-like carbon coating is formed on at least the surface of the rail groove of the outer hook.