JPH0646684U - Sewing machine parts - Google Patents

Abstract

(57) [Summary] [Object] To provide a sewing machine component having a simple structure and stable wear resistance for a long period of time. [Structure] At least a sliding surface of a metal material 5 formed in a predetermined shape is covered with a coating layer 6 made of diamond-like carbon.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sewing machine component, and more particularly to a sewing machine component suitable for a sliding portion that causes high-speed sliding and fretting wear.

[0002]

[Prior art]

 Generally, in sewing machines for industrial use, during sewing, the rotational movement of the sewing machine main shaft is transmitted to the needle bar mechanism via the balance mechanism to move the needle bar up and down, and at the same time, the looper mechanism that cooperates with the vertical movement of the needle bar is used for chain stitching. It is designed to form a seam. In such an industrial sewing machine, it is known that the vertical movement of the needle bar during sewing causes vibration, wear of the sliding portion of the balance mechanism increases, and noise occurs. .

As one means for solving such a problem, in order to improve the wear resistance of the sewing machine parts used in the sliding part of the sewing machine, the sliding surface of the sewing machine parts is covered with a hard coating. Various types of sewing machine parts have been proposed, which are covered with a layer, for example, ceramics such as TiN (titanium nitride) or CrN (chromium nitride), or a hardened layer is formed by nitriding a metal material.

An example of a conventional method of manufacturing such a sewing machine component will be described below.

A conventional sewing machine component of this type, for example, a so-called upper looper hugging or the like is made of chrome molybden steel (SCM415) as a material, and is appropriately cut to have a predetermined shape, followed by a proper thin film forming method. For example, a finished product is formed by forming a hard coating layer such as a TiN layer on at least the sliding surface of the sewing machine component having the predetermined shape by, for example, ion plating.

In this way, the hard coating layer such as the TiN layer formed on the surface of the sewing machine component has a very high hardness of about Hv1500 to Hv1800, and the wear resistance can be improved.

[0007]

[Problems to be solved by the device]

 However, in the above-mentioned conventional sewing machine parts, although the surface hardness can be increased to improve the wear resistance, the durability as a sewing machine part is still not sufficient, and the above-mentioned base material ( When a hard coating layer such as a TiN layer is formed on chrome molybdenum steel by ion plating, for example, in ion plating using the hollow cathode method, the processing temperature during ion plating is high (about 500 ° C). ), The hardness of the base material is lowered, the mechanical strength of the base material is extremely lowered, and there is a problem that a stable function cannot be maintained for a long period of time.

Further, in the ion plating using the arc discharge method, although the treatment temperature during the ion plating treatment can be lowered (about 200 to 250 ° C.), the surface of the surface on which the TiN layer is formed is reduced. The surface roughness is as high as 1.7S after film formation compared to the surface roughness of 0.4S before film formation, and it is difficult to control the film thickness evenly, which makes it possible to achieve high precision in fitting parts and the like. However, there is a problem that it may not be applicable to those requiring high dimensional accuracy.

In addition, in a sewing machine component in which a hard hardened layer is formed by subjecting the base material to a nitriding treatment, the contact portion of the sliding portion is basically a metal-to-metal contact, resulting in fretting wear, that is, However, there is a problem that it is not possible to avoid the phenomenon that wear particles such as red rust are generated when this wear progresses due to high-frequency fine wear.

The present invention has been made in view of these points, overcomes the problems of the conventional ones described above, has a simple structure, and has a stable wear resistance for a long period of time. The purpose is to provide parts for use.

[0011]

[Means for Solving the Problems] In order to achieve the above-mentioned object, a sewing machine component of the present invention is such that at least a sliding surface of a metal material formed in a predetermined shape is covered with a coating layer made of diamond-like carbon. It is characterized by covering.

[0012]

[Action]

 According to the sewing machine component of the present invention having the above-described configuration, by covering at least the sliding surface of the sewing machine component formed of a metal material in a predetermined shape with the coating layer made of diamond-like carbon, The hardness of the sliding surface can be increased, and the wear resistance and fretting wear resistance can be significantly improved.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a front view of a main part of an embodiment of a sewing machine component according to the present invention.

As shown in FIG. 1, the sewing machine component 1 of this embodiment is used for a sliding shaft 4 of an upper looper holder 3 that slides by swinging back and forth with an upper looper guide 2. The base material part is formed of an appropriate metal material 5 such as a chrome molybdenum steel material (SCM415) having a predetermined shape. The metal material 5 is indicated by the diagonal lines in the figure, and at least on the sliding surface, diamond is used. A coating layer (hereinafter referred to as a DLC layer) 6 made of like carbon is formed.

Next, a method of manufacturing the sewing machine component 1 according to the present invention will be described together with its operation.

First, an appropriate metal material 5 such as a chromium molybdenum steel material is formed into a metal material 5 having a predetermined shape by an appropriate processing method such as press molding or cutting.

Next, the metal material 5 formed into a predetermined shape is subjected to an appropriate heat treatment such as a known carburizing method, and then tempered to obtain a desired temper.

As the heat treatment method, it is desirable to use a method in which the deformation of the metal material 5 is small, for example, a soft nitriding method, but it is not particularly limited to this embodiment.

Next, the DLC layer 6 is formed on at least the sliding surface of the tempered metal material 5 by the plasma CVD method (vapor phase growth method) in which the temperature during film formation is about 200 ° C. By doing so, the sewing machine component 1 is manufactured.

The thickness of the DLC layer 6 of this embodiment is about 0.1 to 50 μm, particularly preferably 0.5 to 0.7 μm.

As a result, an extremely hard DLC layer 6 having a hardness of about Hv4000 is formed on at least the sliding surface of the metal material 5.

The hardness (about Hv4000) of the DLC layer 6 formed on at least the sliding surface of the sewing machine component 1 of the present embodiment is determined by the TiN layer formed on the sliding surface of the conventional sewing machine component (not shown). Hardness (about Hv1600), is very excellent in self-sliding property, has a low friction coefficient, and can maintain wear resistance for a long period of time. This can be backed up by the experimental results that the load bearing load at the high-speed rotating portion of 9500 rpm is about twice as high as that of the conventional sewing machine component having the TiN layer in the sliding portion.

Further, a DLC layer 6 is formed on the slide shaft 4 of the upper looper holder 3 which slides by swinging and reciprocating with the upper looper guide 2 shown in FIG. The feed adjustment cam 8 with which the feed cam 7 that is interlocked with and moves in an elliptical manner with fine vibration to generate fretting wear, which is high-frequency fine motion wear that produces wear powder such as red rust, is hatched in the figure. When the DLC layer 6 is formed on at least the sliding surface of the shaft portion 9 as shown, seizure between the upper looper guide 2 and the upper looper holding 3 which occurs when the DLC layer 6 is not formed, and the feed cam 7 and the feed adjusting cam 8 It is possible to reliably prevent fretting wear that occurs in the fitting part of.

Furthermore, since the DLC layer 6 is a very smooth coating, the dimensional accuracy of the fitting portion can be controlled accurately. Further, the DLC layer 6 has a large thermal conductivity and is used for a conventional sewing machine having a TiN layer in the sliding portion when it is used in a high-speed sliding portion of a sewing machine to which a small amount of oil, for example, about 1 cc / min is applied. Compared to the temperature rise of parts, about 80 ° C, the temperature rise is about 70 ° C, which is low, and the resistance against seizure (seizure resistance), which is the welding of members in sliding parts, can be reliably improved. .

Further, the DLC layer 6 formed on at least the sliding surface of the present embodiment has a larger plastic deformation than the TiN layer of the conventional sewing machine component (not shown), and when a large external pressure is applied, The portion of the carbon layer existing in the DLC layer 6 is plastically flowed and has a form like a rolling bearing. Since the DLC layer 6 has a rolling bearing configuration, it is possible to follow fine vibrations and reliably prevent fretting wear.

Furthermore, since the temperature at the time of forming the DLC layer 6 can be set to a low temperature of about 200 ° C., a metal that cannot be tempered at a high temperature, such as SK (carbon tool steel), SCM, SKS (alloy tool steel). ), SKH (high speed tool steel) or the like can be used as the metal material 5 of the sewing machine component 1. Therefore, the metal material 5 of the sewing machine component 1 can be freely selected from various metals according to the design concept.

Further, the sewing machine component 1 according to the present invention can be used for a sliding portion or a movable portion of a needle drive rod, an upper knife rod, a crank rod, etc., which are not shown.

The sewing machine component of the present invention can be applied to general sewing machines such as household sewing machines.

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

[0031]

[Effect of device]

 As described above, according to the sewing machine component of the present invention, the wear resistance is improved by covering at least the sliding surface of the metal material with the coating layer made of high hardness diamond-like carbon. Can be reliably improved. Improving the wear resistance of the sewing machine parts has the practical effect that the function of the sewing machine can be stably maintained for a long period of time and that the life of the sewing machine can be extended.

[Brief description of drawings]

FIG. 1 is a front view showing a main part of an embodiment in which a sewing machine component according to the present invention is used as a sliding shaft of an upper looper holding body that swings and reciprocates with an upper looper guide.

FIG. 2 is a front view showing a main part of an embodiment in which the sewing machine component according to the present invention is used as a feed cam and a shaft portion of a feed adjusting cam that makes an elliptical motion with slight vibration.

[Explanation of symbols]

 1 Parts for sewing machine 2 Upper looper guide 3 Upper looper holder 4 Sliding shaft 5 Metal material 6 DLC layer 7 Feed cam 8 Feed adjustment cam 9 Shaft part

Claims (1)

[Scope of utility model registration request] 1. A sewing machine component characterized in that at least a sliding surface of a metal material formed in a predetermined shape is covered with a coating layer made of diamond-like carbon.