JPH09266996A - Bearing structure of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bearing from seizure by heat generation at a sliding face and wearing of a sliding face, by applying electroless nickel plating containing boron on at least one sliding face of both of a bearing member and borne member of a sawing machine bearing structure comprising the bearing member and the borne member. SOLUTION: An outer shuttle 5 is fixed to the tip part of a lower shaft rotated in a high speed by a motor and has a disc like base part 6 fit on the tip part periphery of the lower shaft and an almost cylindrical outer shuttle main body 10 connected to the tip side of the base part 6. The outer shuttle main body 10 has an almost cylindrical outer periphery wall 12 concentrically protruded at the tip of the base part 6 and connected to the tip side of a base board with a diameter larger than that of the base part 6, and a circular guide groove 14 is formed on the periphery face 12b without periphery wall 12. As such a bearing structure of an outer shuttle structure 5, electroless nickel plating containing boron 12b is applied to the whole surface of the outer shuttle 5 or only the guide groove 5 on which a guide protrusion of the inner shuttle slides to realize a oilless bearing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supports an outer hook on the end of a lower shaft in a sewing machine, and allows an inner hook containing a bobbin to be stationary inside the outer hook while the outer hook is rotating. A bearing structure used in a hook of a sewing machine that is rotatably supported relative to each other, a needle bar device including a needle bar that vertically reciprocates and a bearing member that supports the needle bar, and the like.
The present invention relates to a bearing structure for a sewing machine suitable for use in an industrial sewing machine having a high rotation speed.

[0002]

2. Description of the Related Art In a conventional industrial sewing machine, a needle reciprocates at a maximum of about 5,500 times per minute, so that each part performing an operation related to the operation of the needle has a maximum of 11,000 times per minute. It will rotate about a degree. Therefore, unless the lubricating oil is forcibly supplied to the bearings at such high speeds by the pump, the parts may be overheated and seized or worn.

For example, since a hook in a sewing machine is generally for hooking a lower thread on an upper thread through which a needle is inserted, an inner hook containing a bobbin wound with the lower thread is a needle. Although it remains stationary despite the reciprocating movement of the needle, the outer hook having the hook for hooking the upper thread rotates at a high speed in association with the reciprocating movement of the needle.

Therefore, it is necessary to reduce the sliding resistance as the sliding surface of the inner hook that slides relatively to the outer hook. For this reason, however, the lower shaft that has conventionally supported lubricating oil on the outer hook. The lubricating oil passage formed in the inner pot is supplied to the race surface of the inner pot via another lubricating oil passage formed in the outer pot.

First, a conventional hook of such a sewing machine will be described with reference to FIG.

In FIG. 5, there is provided a lower shaft 1 which can be rotated at a high speed by a driving means such as a motor (not shown). The lower shaft 1 is arranged at an interval in the axial direction.
Axial movement is regulated and supported by a thrust receiver 3 incorporated in a pair of metals 2 (only one is shown). A first lubricating oil passage 4 extending in the axial direction is provided at the center of the lower shaft 1.
Is formed, and the lubricating oil can be supplied into the first lubricating oil passage 4 from the base end side of the lower shaft 1 (not shown).

An outer hook 5 is fixed to the tip of the lower shaft 1. The outer pot 5 has a disk-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 connected to the tip side 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 concentrically provided on the tip of the base 6 and having a diameter larger than that 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, an annular guide groove 14 is formed on the inner peripheral surface 12b of the outer peripheral wall 12 of the outer hook 5.

An inner pot 16 which is rotatable relative to the outer pot 5 is provided in the inner space 15 of the outer pot 5.
The inner pot 16 is formed into a substantially cylindrical shape as a whole, and the outer peripheral surface 16a of the inner pot 16 is fitted in the guide groove 14 of the outer pot 5 and is relatively circumferentially arranged. A substantially ring-shaped guide protrusion 17 that can slide on the outer circumference is provided around the thread except for the portion where the thread comes out. The outer peripheral surface of the guide protrusion 17 is called a race surface. 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. A bobbin (not shown) in which a lower thread is wound is attached to the support pin 19.

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 base plate 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, a holding sleeve 27 for holding a filtering member 26, which is an oil amount limiting member for limiting the amount of oil, is attached to the tip of the lower shaft 1. This holding sleeve 27 is a sleeve main body having an outer peripheral surface formed with a screw portion to be screwed into a screw portion (not shown) formed on the inner peripheral surface forming the first lubricating oil passage 4 of the lower shaft 1. 28 and a flange 29 connected to the sleeve body 28 and having a diameter larger than that of the first lubricating oil passage 4. The flange 29 has an inner side of the sleeve body 28 and the circular shape. A communication hole 30 that communicates with the recess 20 is formed. The inner end of the sleeve body 28 communicates with the communication hole 30, and the communication hole 30 side has a recess 3 formed in a truncated cone shape having a small diameter.
1 is formed. The filter member 26 mounted in the sleeve body 28 is made by solidifying the fibers made of felt or the like as a non-woven fabric into the sleeve body 28.
It has a cylindrical shape that is almost equal to the inner diameter of the.

The material of the sleeve main body 28 may be polyester, sintered material or the like having a relaxation effect.

Next, the operation of the conventional one having the above-mentioned structure will be described.

While the lower shaft 1 is rotating at a high speed together with the outer hook 5 and sewing is performed by a needle (not shown), the lubricating oil at a high pressure is supplied to the first lubricating oil passage 4 of the lower shaft 1 by a pump (not shown). It is being supplied.

If the high-pressure lubricating oil is directly injected from the guide groove 14 of the outer hook 5, the cloth or the like being sewn will be contaminated with the lubricating oil. However, the filtering member 26 is provided in the first lubricating oil passage 4. Is provided, and the oil pressure and the amount of the lubricating oil passing through the filtering member 26 are reduced by the resistance of the filtering member 26 when the lubricating oil passes through the filtering member 26. Then, when passing through the radial passage 22 of the outer pot main body 10 which is rotating at a high speed, the lubricating oil is accelerated to some extent by centrifugal force, and an appropriate amount of lubricating oil is supplied from the guide groove 14 of the outer pot 5 to the inner pot. 16 will be supplied to the guide protrusions 17.

By the way, foreign matter such as cloth waste of sewing products and various abrasion powders may be mixed in the lubricating oil. However, since these foreign matter are filtered by the filter member 26, the filter member 26 is not used. If you continue to use it for a long time,
The filtering member 26 will be clogged, and the lubricating oil will not be supplied to the guide protrusion 17 of the inner pot 16.
Then, the outer pot 5 and the inner pot 16 may generate heat, burn, or may be worn to cause rattling.

Therefore, when such an accident occurs, the outer pot 5, the inner pot 16 and the filtering member 26 must be replaced. To replace the filtering member 26, the holding sleeve 27 is removed. Since it is necessary and troublesome, the user often replaces only the outer pot 5 and the inner pot 16 without replacing the filtering member 26. Then, even if the operation is restarted, since the filter member 26 is still in the clogging state, the accidents of the outer pot 5 and the inner pot 16 may occur again in a short period of time.

Therefore, a so-called oil-free rotary hook has been conventionally developed which enables high-speed rotation of the sewing machine without supplying lubricating oil.

One of the conventional oil-free rotary hooks as described above
As an example, as a material of the pot, there is one in which a filler such as a fluororesin is added to the liquid crystal polymer or high density polyethylene.

However, in such a conventional pot, when the outer pot rotates at a rotational speed of about 8000 revolutions per minute, the outer pot and the inner pot may generate heat or seize. Or, in the case of a hook that does not cause wear and rattle, but the needle rotates up to 11000 times per minute like the outer hook of a high-speed industrial sewing machine in which the needle reciprocates up to 5500 times per minute, the outer hook , The inner pot may generate heat, seize, or wear to cause looseness.

In the case of a kettle that rotates about 11,000 times per minute, the temperature at the sliding parts of the outer kettle and the inner kettle reaches 200 ° C. or higher, but a polymer material such as liquid crystal polymer is used in a high temperature oxygen atmosphere. It is presumed that this is due to the occurrence of oxidative deterioration.

[0023]

Further, as another example of the conventional oil-free rotary hook, the sliding parts of the outer hook 5 and the inner hook 16 are electrolytic chrome plated or electroless nickel-plated to prevent wear. Some are phosphor-plated.

However, although the electrolytic chromium plating has a hardness of about 900 Hv and a considerable wear resistance, the thickness of the deposited film becomes non-uniform and the dimensional accuracy cannot be obtained. there were.

When electroless nickel-phosphorus plating is applied, the hardness of the film is about 400 Hv, and it is necessary to perform heat treatment at about 400 ° C. to improve wear resistance. When the heat treatment is performed, the hardness of the electroless nickel-phosphorus plating film is 900 to 1000 Hv.
However, if the base of the outer pot 5 and the inner pot 16 is carburized and hardened, the hardness of the base itself is lowered or deformed, and the base of the outer pot 5 and the inner pot 16 is When the resin is a resin, the resin component is decomposed and deformed, so that even if the hardness of the electroless nickel-phosphorus plating is improved, the wear of the outer pot 5 and the inner pot 16 is finally reduced. There was a problem of not being connected.

Although wear can be reduced by increasing the hardness of plating by compounding nickel-phosphorus with ceramics or metal oxides, the wear of the mating material can be reduced by the composite material ceramics or metal oxides. There was a problem of increasing.

Also, in the bearing structure of the needle bar device in which the needle bar made of a metal material and reciprocating in the vertical direction is slidably held by using a metal bearing member, the bearing structure slides at a high speed of the sewing machine. The moving surface generates heat, and this heat generation may cause seizure damage (the needle bar may be seized with the bearing and the needle bar may not operate), wear, or heat may be generated. In order to prevent damage and wear, even in the needle bar device, a structure has been used in which an oil supply means is provided on the sliding surface of the bearing structure to forcibly supply the lubricating oil.

However, providing the lubricating means for forcibly supplying the lubricating oil to the sliding surface of the needle bar device of the conventional industrial sewing machine complicates the sewing machine structure and increases the number of parts, resulting in cost reduction. In addition to increasing the amount, it is difficult to properly control the amount of lubricating oil supplied to the sliding surface (lubrication amount). If the amount of lubricating oil supplied to the sliding surface is large, the sewn product is contaminated with lubricating oil. There was a problem that there are cases. On the contrary, when the amount of oil supplied to the sliding surface is reduced by a small amount of oil using an oil core or oil mist, or grease is supplied, it may not be possible to reliably prevent seizure damage, wear, and heat generation.

In view of the above, the present invention is suitable for application to a high-speed sewing machine in which the outer hook rotates up to about 11,000 times per minute, and the hook of the sewing machine does not need to be supplied with lubricating oil. An object of the present invention is to provide a highly durable bearing structure for a sewing machine that can completely prevent the sliding surface of a needle bar device, etc. from generating heat, seizing, or causing rattling. To do.

[0030]

In order to achieve the above object, a bearing structure for a sewing machine according to claim 1 of the present invention is an electroless electroless device containing boron on at least one sliding surface of a bearing member and a supported member. It is characterized by being plated with nickel.

According to the bearing structure of the sewing machine of the present invention as defined in claim 1, it is possible to obtain a film having a high hardness without lowering the hardness of the material or deforming the shape of the member itself. The sliding surface plated with electroless nickel containing boron can reduce the wear of the member.

Further, in the bearing structure of the sewing machine according to claim 2 of the present invention, at least the sliding surface of one of the bearing member and the bearing member is plated with electroless nickel containing boron. At least the sliding surface of the other member is formed of a heat resistant resin.

According to the bearing structure of the sewing machine of the second aspect of the present invention, the sliding surface formed of the heat resistant resin has a low deterioration rate in a high temperature oxygen atmosphere, and a film having high hardness can be obtained. The sliding surface plated with electroless nickel containing boron can reduce wear of the plated member.

According to a third aspect of the present invention, there is provided a bearing structure for a sewing machine, which has a substantially cylindrical shape in which an annular guide groove is formed on an inner peripheral surface of an outer peripheral wall at an end of a lower shaft which is driven to rotate or swing. The outer hook is shaped like a circular ring and is provided on the outer peripheral surface of the outer hook with a guide ring that fits in the guide groove of the outer hook and that can slide relatively in the circumferential direction. In a bearing structure of a sewing machine in which a substantially cylindrical inner hook is supported so as to be rotatable relative to the outer hook, the guide groove of the outer hook is plated with electroless nickel containing boron. The guide protrusions are formed of heat resistant resin.

According to the bearing structure of the sewing machine according to the third aspect of the present invention, in the sewing machine hook, the guide protrusion of the inner hook formed of the heat-resistant resin has a low deterioration rate in a high temperature oxygen atmosphere and has a high hardness. The guide groove plated with electroless nickel containing boron, which can obtain a high film,
The wear of the plated member can be reduced, and even if the guide projection and the guide groove slide, they can be prevented from generating heat or burning due to friction.

In the bearing structure of the sewing machine according to a fourth aspect of the present invention, in the needle bar device of the sewing machine, a needle bar having a sliding surface and arranged so as to be vertically movable, and the needle bar in the vertical direction. In a bearing structure of a sewing machine including a pair of upper and lower needle bar bearings having a sliding surface for supporting reciprocating slidability, a sliding surface of the needle bar is plated with electroless nickel containing boron. And the sliding surface of the needle bar bearing is formed of a heat resistant resin.

According to the bearing structure of the sewing machine of the fourth aspect, in the needle bar device of the sewing machine, as in the bearing structure of the sewing machine of the preceding paragraph, the sliding surface of the needle bar bearing made of heat resistant resin is A needle bar plated with electroless nickel containing boron, which has a low deterioration rate in a high-temperature oxygen atmosphere and can obtain a film with high hardness, reduces wear of the sliding surface subjected to the plating treatment. Even if the sliding surface of the needle bar bearing and the sliding surface of the needle bar slide, it is possible to prevent them from generating heat or burning due to friction.

A bearing structure for a sewing machine according to a fifth aspect is the bearing structure for a sewing machine according to any one of the first to fourth aspects, wherein the electroless nickel plating containing boron is nickel-boron or nickel. -Tungsten-boron or nickel-phosphorus-boron.

According to the bearing structure of the sewing machine of the fifth aspect, since the friction coefficient is particularly small, the wear resistance can be further improved.

A sewing machine bearing structure according to a sixth aspect of the present invention is the sewing machine bearing structure according to any of the second to fifth aspects, wherein the heat-resistant resin is polyimide.

According to the bearing structure of the sewing machine of the sixth aspect, the strength is not particularly reduced at a high temperature, and even if the sliding surface and the sliding surface of the bearing structure slide, heat is generated due to friction. It is possible to prevent burning or burning.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows an outer hook main body 10 formed in a substantially cylindrical shape of an outer hook 5 having a bearing structure for a sewing machine according to the present invention.

The outer pot 5 is fixed to the tip of the lower shaft 1 which can be rotated at a high speed by a driving means such as a motor (not shown), and has a disk shape fitted to the outer periphery of the tip of the lower shaft 1. 1 and a substantially cylindrical outer pot main body 10 connected to the tip side of the base 6.

The outer pot main body 10 is provided with a substrate 11 having a diameter larger than that of the base 6 and 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. And the inner peripheral surface 12b of the outer peripheral wall 12 of the outer hook 5.
An annular guide groove 14 is formed in the groove.

FIG. 2 is an enlarged sectional view showing the guide groove 14 of the outer hook 5.

In the present embodiment, the outer pot 5 is made of metal such as iron or stainless steel (shown by diagonal lines in FIG. 2).
And electroless nickel-boron plating (indicated by a mesh in FIG. 2) is applied to the entire surface. The electroless nickel-boron plating may be applied only to the guide groove 14 of the outer pot 5 that slides on the guide protrusions 17 of the inner pot 16. Also,
The electroless nickel-boron plating may be electroless nickel plating containing boron, such as electroless nickel-phosphorus-boron plating or electroless nickel-tungsten-boron plating. Here, the reason why the nickel plating contains boron is that attention is paid to the sliding characteristics of boron. In this embodiment, the content of boron is more than 0 and less than 1%. And
Plating containing these boron is, for example, 1 minute per minute.
Even when the temperature of the sliding portion of the outer pot 5 and the inner pot 16 of the pot that rotates about 1000 times reaches 200 ° C. or higher, it exhibits excellent characteristics that it does not undergo oxidative deterioration in the high temperature oxygen atmosphere. It will be.

An inner pot 16 which is rotatable relative to the outer pot 5 is provided in the inner space 15 of the outer pot 5. As shown in FIG. 3, the inner pot 16 is generally formed in a substantially cylindrical shape.
Reference character 1a is a substantially annular guide projection 1 which is fitted in the guide groove 14 of the outer hook 5 and can slide relatively in the circumferential direction.
7 is provided around the thread except for the part where the thread comes off.

FIG. 4 is an enlarged sectional view showing the guide protrusion 17 of the inner hook 16.

In this embodiment, the guide protrusion 17 of the inner hook 16 which slides in the guide groove 14 of the outer hook 5.
Is made of polyimide as a heat resistant resin (shown by meshes in FIG. 4). The guide protrusions 17 may be formed by using a heat resistant resin as a base material and adding a reinforcing material such as carbon fiber to the base material.

As this material, 1. Polyimide as a heat-resistant resin as a base material, to which 20 to 30% by weight of carbon fiber is added as a reinforcing material. Polyimide as a heat resistant resin is used as a base material, and 20 to 30% by weight of carbon fiber is added as a reinforcing material to the base material, and at least one of graphite and polytetrafluoroethylene is added at 5 to 10% by weight in order to further improve lubrication characteristics. What was added 3. 3. A base material of polyether / etherketone as a heat resistant resin, to which 20 to 30% by weight of carbon fiber is added as a reinforcing material. Polyether / etherketone is used as a heat resistant resin as a base material, and 20 to 30% by weight of carbon fiber is added as a reinforcing material to the base material, and at least one of graphite and polytetrafluoroethylene is added to improve lubrication characteristics. Four kinds of -10% by weight can be exemplified.

Since these heat-resistant resins contain carbon fibers, they exhibit the characteristic of low sliding resistance.

A support plate 18 is attached integrally to the base end portion of the inner pot 16, and the support plate 18 is extended in the diametrical direction. The inner pot 16 is provided at the center of the support plate 18 in the longitudinal direction.
A support pin 19 extending in the axial direction is coaxially projected. A bobbin (not shown) in which a lower thread is wound is attached to the support pin 19.

The inner pot 1 excluding the guide protrusions 17
In the present embodiment, the other portions of 6 are made of metal such as iron or stainless steel (indicated by diagonal lines in FIG. 4), but the entire inner pot 16 is made of heat resistant resin. Needless to say, it is okay. The structure of the hook portion of the other sewing machine is substantially the same as the structure described in the conventional example, and the description thereof will be omitted.

With the above construction, when the sewing machine having the bearing structure of the present invention operates and the outer hook 5 is rotated by the driving means such as a motor (not shown), the guide for the outer hook 5 shown in FIGS. The groove 14 and the guide protrusion 17 shown in FIGS. 3 and 4 slide.

At this time, in the present embodiment, the surface of the outer pot 5 including the guide groove 14 is electroless nickel-boron plated. Since the electroless nickel plating containing boron can be processed at a low temperature of about 60 ° C., the hardness of the material forming the base of the outer pot 5 is not lowered, and the outer pot 5 is not deformed, so that the hardness of the outer pot can be improved. A high film can be obtained. The hardness of the film is 750.
Since it has a wear resistance of up to 900 Hv, the wear of the outer pot 5 can be reduced. Moreover, since nickel-boron plating and nickel-phosphorus-boron plating have a small coefficient of friction, wear resistance can be further improved.

As described above, even if the heat treatment at a high temperature that affects the hardness and the shape of the outer pot 5 itself is not performed, the wear resistance is better than that of the conventional nickel-phosphorus plating and the high temperature heat treatment. Obtainable. Further, since nickel-phosphorus is not combined with ceramics or metal oxides, wear of the mating material is not increased.

Further, the nickel-boron plating has a hardness of 1000 or higher due to heat treatment at a low temperature (around 300 ° C.), a friction coefficient is lowered, and wear resistance is further improved, as compared with nickel-phosphorus plating. By using a high temperature tempered (400 ° C. or higher) material such as SKD (alloy tool steel material) or SKH (high speed tool steel material) as the base material, there is no deformation and no deformation of the base material hardness, which is more effective.

Further, in the present embodiment, a heat resistant resin such as polyimide is used as a mating material that slides on the nickel-boron plating applied to the outer pot 5, but the heat resistant resin such as polyimide is high temperature oxygen. The deterioration rate in the atmosphere is slow, and when carbon fiber is added as a reinforcing material, the rigidity at high temperature can be secured.

Therefore, the outer pot 5 has a maximum of 1100 per minute.
An inner hook 16 having the guide projections 17 formed of these materials is applied to a high-speed rotating sewing machine that rotates about 0 times, and an outer hook 5 having a nickel-plated guide groove 14 containing boron. If it is applied, it becomes possible to smooth the sliding and to completely prevent the sliding portions of the outer pot 5 and the inner pot 16 from generating heat or burning without supplying the lubricating oil. The sewing speed can also be improved.

The present invention is not limited to the above-mentioned embodiment, but various modifications can be made if necessary.

For example, in the embodiment described above, the electroless nickel plating containing boron is applied to the outer pot. However, only the entire surface of the inner pot or only the guide projection portion which is the sliding surface of the inner pot is subjected. Electroless nickel plating containing boron may be applied, or electroless nickel plating containing boron may be applied to both the outer pot and the inner pot.

Further, in the above-mentioned embodiment, the full rotary hook is explained, but the present invention is also applicable to the half rotary hook. In the case of this half-turn hook, the lower shaft swings. Further, the bearing structure of the sewing machine of the present invention is not limited to use only in the hook portion of the sewing machine described above, and for example, a needle bar or a presser bar made of a metal material of the sewing machine and vertically reciprocating is made of metal. It is also possible to use it for a bearing structure in which it is slidably held using the above bearing member.

[0064]

As described above, according to the bearing structure of the sewing machine of the present invention, the wear of the electroless nickel-plated member containing boron can be surely reduced, and the wear of the sewing machine can be improved. If a heat-resistant resin is used as the mating material that slides with the electroless nickel-plated member containing boron, the sliding surface can be prevented even if lubricating oil is not supplied. It is possible to reliably prevent the heat generation and the seizure, and it is possible to improve the durability of the industrial sewing machine in which the number of rotations of the shuttle is high.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of an outer hook having a bearing structure for a sewing machine according to the present invention.

FIG. 2 is an enlarged sectional view showing a guide groove of the outer hook of FIG.

FIG. 3 is a front view showing an embodiment of an inner hook having a bearing structure for a sewing machine according to the present invention.

4 is an enlarged cross-sectional view showing a guide protrusion of the inner pot of FIG.

FIG. 5 is a vertical cross-sectional view showing a structure of a hook portion of a conventional sewing machine.

[Explanation of symbols]

 5 Outer hook 10 Outer hook main body 12 Outer peripheral wall 12b Inner peripheral surface 14 Guide groove 16 Inner hook 16a Outer peripheral surface 17 Guide protrusion

Claims (6)

[Claims] 1. A bearing structure of a sewing machine comprising a bearing member and a bearing member, wherein at least one sliding surface of the bearing member and the bearing member is plated with electroless nickel containing boron. The bearing structure of the sewing machine, which is characterized in that 2. A bearing structure of a sewing machine comprising a bearing member and a supported member, wherein an electroless nickel plating containing boron is formed on a sliding surface of one of the bearing member and the supported member. The bearing structure of the sewing machine is characterized in that the sliding surface of the other member is formed of a heat resistant resin. 3. A substantially cylindrical outer pot having an annular guide groove formed on an inner peripheral surface of an outer peripheral wall is supported at an end portion of a lower shaft which is rotated or rocked, and the inner pot of the outer pot is supported. A substantially cylindrical inner pot having an outer circumferential surface fitted with a guide groove of the outer pot and provided with a substantially annular guide protrusion capable of relatively sliding in the circumferential direction, relative to the outer pot. In a bearing structure of a sewing machine rotatably supported, the guide groove of the outer hook is plated with electroless nickel containing boron, and the guide protrusion of the inner hook is made of heat-resistant resin. The bearing structure of the sewing machine. 4. A needle bar device of a sewing machine, which is arranged so as to be vertically movable, has a needle bar having a sliding surface, and a vertical plane having a sliding surface for supporting the needle bar so that it can reciprocate vertically. In a bearing structure of a sewing machine composed of a pair of needle bar bearings, the sliding surface of the needle bar is plated with electroless nickel containing boron, and the sliding surface of the needle bar bearing has a heat-resistant resin. A bearing structure for a sewing machine, characterized in that 5. The electroless nickel plating containing boron is any one of nickel-boron, nickel-tungsten-boron and nickel-phosphorus-boron. 2. A bearing structure for a sewing machine according to item 1. 6. The bearing structure for a sewing machine according to claim 2, wherein the heat resistant resin is polyimide.