JP2004041304A - Needle bar driving mechanism for sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of a needle driving mechanism in the state of oil-free. <P>SOLUTION: The mechanism is provided with: a needle bar (20) which supports a sewing machine needle at its distal end part and supported by a sewing machine frame (1) in the state of being reciprocative along a longitudinal direction of its own; a needle driving arm (40) for imparting driving force of the reciprocating operation of this needle bar to the needle bar; and a needle bar driving link (50) for connecting the needle bar with the needle driving arm.The needle bar driving link is connected rotatably by pin members (22 and 42a) with respect to either of the needle bar and the needle driving arm. The respective pin members are formed of steel material, and a ceramic coating film consisting of chromium nitride is formed on a sliding face of at least the respective pin members and the needle bar driving link. The needle bar driving link is formed of light metal, and a hard anodization film is formed on a sliding face of at least the needle bar driving link and the respective pin members. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a needle bar drive mechanism of a sewing machine, and more particularly, to a needle drive mechanism of a sewing machine for eliminating oiling around a sewing needle.
[0002]
[Prior art]
Conventional sewing machines generally include a lubrication mechanism of a forced lubrication system. However, a sewing machine provided with such a forced lubrication type lubrication mechanism has a possibility of causing stains on the cloth and around the sewing machine due to oil leakage.
However, lubrication is indispensable in the conventional sewing machine, and if the sewing machine is driven without performing this operation, burning due to frictional heat will occur, and the durability will be reduced to a level that cannot be practically used at all.
Therefore, as a countermeasure against such oil leakage, a minute oil supply method that reduces the amount of oil supply or an oil wick oil supply method that supplies oil to a predetermined portion via a string-shaped oil wick is adopted. Leak prevention measures were taken.
[0003]
[Problems to be solved by the invention]
However, since the lubricating oil is used for both the micro lubrication and the oil wick lubrication, oil leakage is still unavoidable even if the amount of leakage is reduced. Further, since the supply amount of the lubricating oil is reduced, a sufficient effect cannot be obtained for a sewing machine having a high surface pressure portion or a high-speed sliding portion inside a mechanism like a lock sewing machine, for example.
[0004]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a needle bar drive mechanism of a sewing machine which solves the above-mentioned conventional problems, avoids lubricating oil leakage, and sufficiently withstands high speed and high surface pressure.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, a needle bar (20) supported by a sewing machine frame (1) so as to be able to reciprocate along its own length while supporting a sewing needle at its tip end, A needle drive arm (40) for providing a driving force for operation and a needle bar drive link (50) for connecting the needle bar and the needle drive arm are provided, and the needle bar drive link is provided between the needle bar and the needle drive arm. Each of them is rotatably connected by a pin member (22, 42a), and each pin member is formed of a steel material, and at least the sliding surface of each pin member with the needle bar drive link is made of chromium nitride. A configuration is adopted in which a ceramic coating film is formed, the needle bar drive link is formed of light metal, and a hard anodic oxide film is formed on at least the sliding surface of the needle bar drive link with each pin member.
[0006]
The sewing machine is generally performed on the premise that the sewing needle moves up and down. The above-described needle bar, the needle drive arm, and the needle bar drive link always operate to realize the vertical movement of the sewing needle. In order to increase the speed of each operation by the sewing machine, it is a natural premise that the vertical movement of the sewing needle is increased. Furthermore, when the sewing needle penetrates the laid fabric like the lock sewing machine described above, a high surface pressure is generated in each part supporting the sewing needle with the increase in speed. Is required to have durability against fretting wear that may occur.
On the other hand, regarding the configuration for supporting the sewing machine needle, it is usually arranged above the fabric, and as a result of the lubricating oil reaching the sewing machine needle via the needle bar, there are factors that cause the fabric to be stained. Therefore, it was a configuration in which the need for lubrication was particularly desired.
[0007]
Therefore, in the configuration of the first aspect of the present invention, a reciprocating operation of the needle driving arm that generates a constant reciprocating operation and a needle bar that moves up and down together with the sewing machine needle are connected by a needle bar driving link to form a two-bar linkage. In contrast to the configuration in which the reciprocating operation of the needle drive arm can be smoothly transmitted to the needle bar, among these configurations, the connection between the needle bar drive link, which is particularly susceptible to deterioration, and the other two configurations is connected. The durability of each pin member and the part receiving the pin member is improved.
That is, a chromium nitride film is formed on at least a portion of the peripheral surface of the pin member that slides with the needle bar drive link, and a hard anodic oxidation is formed on a portion of the needle bar drive link that slides with the pin member. A coating is formed. These are all ceramics, and have heat resistance, abrasion resistance, and corrosion resistance as characteristics, and exhibit high durability against frictional heat caused by mutual sliding. Therefore, it is sufficiently durable to fretting friction due to oillessness around the sewing needle.
[0008]
Furthermore, in the above configuration, a porous layer is formed by forming a hard anodic oxide film on the sliding surface of the needle bar drive link, and grease can be held in the porous portion of the porous layer. Therefore, when grease is held on such a sliding surface, the sliding between the pin member and the needle bar drive link is made smooth, and deterioration due to heat generation of sliding friction and wear due to sliding can be avoided. On the other hand, unlike the case of liquid lubricating oil, even when grease is used, contamination does not occur due to oil leakage.
[0009]
The invention according to claim 2 has the same structure as the invention according to claim 1, and adopts a structure in which the coating film of each pin member is formed by an ion plating method.
In the above configuration, the durability of the pin member and the portion receiving the pin member is improved as in the first aspect of the invention, and the chromium nitride film is formed by the ion plating method. Compared with the film formation, it is possible to make the film thickness extremely thin, and since high temperature heating is not performed in the thermal spraying process, there is no change in the properties or deterioration of the base material of the pin member.
Further, the film formed by the ion plating method has good adhesion, and has durability against peeling and deterioration due to sliding.
[0010]
According to the third aspect of the present invention, a needle bar supported by a sewing machine frame that supports the sewing machine needle at its tip end and that can reciprocate along its own longitudinal direction, and imparts a driving force to the needle bar for the reciprocating operation. A needle drive arm for connecting the needle bar and the needle drive arm, the needle bar drive link being rotatable by a pin member with respect to both the needle bar and the needle drive arm. Each pin member is formed of a steel material, and a coating film of a ceramic material is formed on at least a sliding surface of each pin member with the needle bar drive link by an ion plating method, and the needle bar drive link is made of light metal. The hard anodized film is formed on at least the sliding surface of the needle bar drive link with each pin member.
[0011]
In the above configuration, for the same reason as the invention described in claim 1, each pin member for connecting the needle bar drive link, which is particularly likely to deteriorate in the sewing machine, and the other two configurations, and The durability of the receiving part is improved.
Therefore, a ceramic film suitable for the ion plating method is formed on a portion where the pin member slides, and a hard anodic oxide film is formed on a portion of the needle bar drive link which slides with the pin member. I have. These are all ceramics, and have excellent heat resistance, abrasion resistance, and corrosion resistance as compared with iron, stainless steel, aluminum alloy, and the like, and have improved durability against frictional heat caused by mutual sliding. . Therefore, improvement in durability against fretting wear due to no lubrication around the sewing needle is achieved.
In addition, since a ceramic suitable for ion plating is employed, if such a film forming method is employed, the film thickness can be reduced, the characteristic change and deterioration of the base material of the pin member can be avoided, and peeling and deterioration of the film occur. To reduce.
[0012]
The invention described in claim 4 has the same configuration as the invention described in claim 1, 2, or 3, and adopts a configuration in which the light metal forming the needle bar drive link is aluminum or an alloy thereof.
In the above configuration, the same operation as that of the first, second, or third aspect of the invention is performed, and the base material of the needle bar drive link is aluminum having a low specific gravity or an alloy thereof. The surface pressure between the pin member and the pin member, which is generated when the motor is driven at high speed, is reduced.
[0013]
The invention described in claim 5 has the same configuration as the invention described in claim 1, 2, 3, or 4, and adopts a configuration in which a steel material forming each pin member is an SKH material.
In the above configuration, the same operation as that of the first, second, third, or fourth aspect of the invention is performed, and among the steel materials, SKH is less likely to change its characteristics or deteriorate even at a high temperature. The strength is maintained even at the time of sliding during use, and the durability is maintained.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
(Overall Configuration of Embodiment of the Invention)
A needle bar drive mechanism 10 of a sewing machine according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view in which a part of a lock sewing machine 100 for performing overlock sewing or overlock sewing to which the needle driving device 10 is applied is cut open, and FIG. 2 is a cross section taken along line ZZ in FIG. FIG. 3 is an explanatory diagram showing a connected state of the needle driving arm 40, the needle bar 20, and the needle bar driving link 50 disclosed in FIG. The following description is based on the premise that the lock sewing machine 100 is mounted on a horizontal plane, in which a vertical direction is defined as a vertical direction, and one direction orthogonal to the vertical direction is defined as a horizontal direction in FIG. A direction (horizontal direction in FIG. 2) orthogonal to both the up-down direction and the left-right direction is referred to as the front-back direction.
[0015]
As shown in FIG. 1, the needle bar drive mechanism 10 supports a sewing needle (not shown) at its tip and a needle bar 20 supported on the sewing machine frame 1 so as to be able to reciprocate along its own longitudinal direction. The needle drive arm 40 is provided with a needle drive arm 40 that applies the driving force of the reciprocating operation to the bar 20, and a needle bar drive link 50 that connects the needle bar 20 and the needle drive arm 40.
[0016]
(Needle bar)
The needle bar 20 has upper and lower ends supported by a needle bar upper metal 2 and a needle bar lower metal 3 mounted on the sewing machine frame 1. Each of these metals 2 and 3 is formed of a cylindrical material having good slippage such as phosphor bronze.
As shown in FIG. 2, the needle bar 20 has a solid middle portion in the longitudinal direction, and the other portion is hollow throughout the entire length. The solid portion of the needle bar 20 is provided with a through-hole 21 in a direction orthogonal to the center line C. The through-hole 21 is used to rotatably connect a needle bar drive link 50 described later. The second pin member 22 is inserted. The second pin member 22 is fixed by a set screw 23 so as to prevent itself from rotating inside the through hole 21. Accordingly, when the needle bar drive link 50 rotates with respect to the needle bar 20, the second pin member 22 does not slide between the needle bar 20 and the sliding portion of the needle bar drive link 50. Will slide between them.
[0017]
(Needle drive arm)
One end 41 of the needle drive arm 40 is fixedly connected to the needle drive shaft 30 supported by the sewing machine frame 1 so as to be rotatable about a rotation axis extending in the front-rear direction. The needle drive shaft 30 is configured to perform high-speed reciprocal rotation drive within a predetermined rotation angle range by a configuration not shown. Therefore, the rotation end 42 of the needle drive arm 40 performs a high-speed swinging movement around the needle drive shaft 30 within the above-described predetermined angle range. Specifically, the turning end 42 of the needle driving arm 40 reciprocates substantially along the vertical direction, and its turning range is between the solid line and the two-dot chain line in FIG.
[0018]
As shown in FIG. 3, the rotating end 42 of the needle drive arm 40 branches into two branches, and the needle bar drive link 50 and the needle bar 20 enter inside the branched end. The rotation end 42 of the needle drive arm 40 is rotated between first ends of the needle bar drive link 50 via first pin members 42a, 42a arranged in the front-rear direction. They are connected so that they can move freely. Each of the first pin members 42a, 42a is fixed by a screw (not shown) so as not to rotate with respect to the needle driving arm 40. Therefore, when the needle bar drive link 50 rotates with respect to the needle bar drive arm 40, each of the first pin members 42a, 42a does not slide between the needle drive arm 40 and the needle bar drive link 50. Sliding is performed between the sliding contact portions of the link 50.
[0019]
(Needle bar drive link)
As described above, the needle bar drive link 50 is connected to the rotation end of the needle drive arm 40 via the first pin members 42a and 42a at one end 51 in the longitudinal direction so as to be rotatable with each other. The other end 52 in the longitudinal direction is connected to the needle bar 20 via the second pin member 22 so as to be rotatable with each other. Each of the pin members 22 and 42a is provided in parallel in the front-rear direction in the same manner as the needle drive shaft 30.
The needle bar drive link 50 has a substantially U-shaped cross section at one end 51 perpendicular to the longitudinal direction, as shown in FIG. The needle bar drive link 50 connects each of the first pin members 42a, 42a so that the substantially U-shaped opening side faces the opening side of the forked portion of the rotating end portion 42 of the needle driving arm 40 described above. The needle bar 20 is connected to the needle drive arm 40 through the needle bar 20 and the needle bar 20 is inserted into the substantially U-shaped inner portion. It is arranged almost along.
[0020]
(Mutual operation of each component of the needle bar drive mechanism)
The needle bar 20, the needle driving arm 40, and the needle bar driving link 50 are connected as described above to form a two-bar linkage.
Explaining these mutual operations, first, the needle driving arm 40 reciprocates the rotating end 42 within the angular range of FIG. 1 with the driving of the needle driving shaft 30. At this time, since the turning end 42 of the needle driving arm 40 draws an arc centered on the needle driving shaft 30, the turning end 42 moves in the vertical direction (more precisely, in the direction of the center line C of the needle bar 20). In the process of generating displacement and reciprocating, displacement occurs in the left-right direction (more precisely, the direction perpendicular to the center line C). The vertical displacement of the rotating end 42 of the needle drive arm 40 is transmitted to the needle bar 20 via the needle bar drive link 50, and the sewing needle moves up and down together with the needle bar 20. Further, the displacement of the rotating end 42 of the needle driving arm 40 in the left-right direction is eliminated by the needle bar driving link 50 constantly rotating with respect to the needle bar 20.
[0021]
(Material and surface treatment of the needle bar drive link and each pin member)
In the lock sewing machine 100 according to the present embodiment, the respective components of the above-described needle bar drive link 10 are made to be oil-free, lubricating oil is transmitted to the sewing machine needle to contaminate the fabric, and leakage around the sewing machine 100 due to lubricating oil leakage. It tries to prevent polluting the environment.
However, in the needle bar drive mechanism 10, since the vertical movement of the rotating end portion 42 of the needle drive arm 40 is transmitted to the needle bar 20 via the needle bar drive link 50, the first and second connecting members are connected. The surface pressure generated between the respective peripheral surfaces of the pin members 22 and 42 a and the sliding portions at the ends 51 and 52 of the needle bar drive link 50 increases due to the inertial force of the needle bar 20. Under these high surface pressures, sliding occurs between the peripheral surfaces of the first and second pin members 22 and 42a and the sliding portions at the ends 51 and 52 of the needle bar drive link 50 constantly. Done.
In such a portion where sliding is constantly performed under a high surface pressure, if no lubrication is carried out without any provision, it is usual that the durability is remarkably reduced, or burning is caused to make it unusable.
[0022]
Therefore, in the needle bar drive mechanism 10, first, the first and second pin members 22, 42a are both formed of SKH51 (high-speed steel), which is a steel material. The first and second pin members 22, 42a are quenched and tempered in the state of a base material, and after strengthening, the entire peripheral surface on which sliding is performed is coated with a ceramic coating made of chromium nitride. To form Such a chromium nitride film is formed at a film pressure of about 2 [μm] on the peripheral surfaces of the pin members 22 and 42a by an ion plating method, which is a kind of physical vapor deposition method.
[0023]
On the other hand, the needle bar drive link 50 is formed of aluminum or a stronger aluminum alloy as the base material. Since the specific gravity of aluminum or its alloy is about one third of that of iron, the weight of the entire needle bar drive link 50 is reduced, and the first and second pin members 22 and This is to reduce the surface pressure between the respective peripheral surfaces of the needle bar 42a and the sliding portions at the ends 51 and 52 of the needle bar drive link 50. In consideration of weight reduction, magnesium or an alloy thereof may be used, but aluminum or an alloy thereof is preferable in terms of strength. The sliding surfaces of the both ends 51, 52 of the needle bar drive link 50 with the respective pin members 22, 42a are formed with an alumina film, which is a hard anodic oxide film. Since a porous layer is formed on the surface of the hard anodic oxide coating, grease can be retained by utilizing the porous structure of the porous layer.
[0024]
As described above, when the chromium nitride film is formed on the outer peripheral surface of each of the pin members 22 and 42a and the hard anodic oxide film is formed on the sliding surface of the needle bar driving link 50, the chromium nitride film is also hard anodic oxide. Each of the coatings is made of ceramic and has heat resistance, abrasion resistance, corrosion resistance, and oxidation resistance as its characteristics, and exhibits high durability against frictional heat caused by mutual sliding. Further, since the hard anodic oxide coating has a low coefficient of friction and the chromium nitride film is particularly excellent in heat resistance among the ceramic coatings, a combination of these is used for the needle bar drive link 50 and the pin members 22 and 42a. It exhibits sufficient durability against fretting wear caused by the vertical movement between the two.
[0025]
FIG. 4 is a comparative test result when the needle bar 20 is moved up and down using the needle bar drive link having the same structure and the first and second pin members having been subjected to various materials and various surface treatments. . As a prerequisite for the test, the endurance time was determined while keeping the rotation speed of the drive source of the needle drive shaft 30 at 6300 [rpm] (the same applies to the vertical vibration frequency of the needle bar 20). (1) shows the case where each pin member is made of SUJ2 (bearing steel) and the needle bar drive link is made of SCM415 (chrome molybdenum steel) without lubrication. WC / C (tungsten carbide / carbon), needle bar drive link is shown as SCM415, when performed without lubrication. (3) shows each pin member as base material SUJ2, CrN (chromium nitride) coating, needle bar drive The case where the link is used as the base material SCM415 and the coating is NiB (nickel / boron) and the coating is performed without lubrication is performed. (4) indicates that each pin member is used as the base material SUS440C (stainless steel) and the sliding surface thereof is ion-nitrided. FIG. 5 shows a case where the needle bar drive link is set as the SCM 415 without lubrication, and {circle around (5)} indicates the respective pin members 22, 42a, the needle, and the needle of the needle bar drive mechanism 10 of the present embodiment. Drive link 50 indicating the (grease used).
As shown in FIG. 4, in the configuration (5) of the needle bar driving mechanism 10, the durability time thereof is 7000 hours, and compared with the other comparative examples (1) to (4), under no lubrication. It can be seen that the durability of this is remarkably excellent. In (5), the endurance time is 7000 hours. However, the endurance test is still ongoing, and the actual endurance time exceeds 7000 hours. A conventional needle bar drive mechanism of a sewing machine that performs refueling generally has a durability time of about 4000 hours, and the continuous operation time of about 5000 hours is the life of the entire sewing machine. According to the configuration of the needle bar drive mechanism 10, it exceeds these values, demonstrating the durability without lubrication.
[0026]
(Other)
The base material of each of the pin members 22 and 42a may be SCM (chromium molybdenum steel), SKD (alloy tool steel), or SUJ (bearing steel). The use of a stable SKH (high speed steel) is more desirable.
As the ceramic film formed on the peripheral surfaces of the pin members 22, 42a, other ceramics capable of forming a film by an ion plating method, for example, TiN (titanium nitride), TiAlN (titanium aluminum nitride), TiCN ( Titanium carbonitride), TiC (titanium carbide) or the like may be used. However, since these ceramics have somewhat lower heat resistance than CrN (chromium nitride), when the surface pressure between the needle bar drive link and each link member is high (for example, 2.0 [MP] or more), It is also desirable to employ a CrN coating.
[0027]
(Other examples of needle bar drive mechanism)
The application of the present invention relating to the material and surface treatment of the above-described needle bar drive link 50 and each of the pin members 22 and 42a is not limited to the mechanical structure of the needle bar drive mechanism 10 described above, As long as the needle driving arm and the needle bar are connected via the link and the first and second pin members, the present invention may be applied to a needle bar driving mechanism having another mechanical structure. The other needle bar drive mechanism 10A will be described with reference to FIG.
[0028]
FIG. 5 is an exploded perspective view of the needle bar drive mechanism 10A. In such a configuration, the same components as those of the needle bar driving mechanism 10 described above are denoted by the same reference numerals, and redundant description will be omitted.
The needle bar drive mechanism 10A supports the sewing machine needle M at the tip end thereof, and reciprocates along its own longitudinal direction. The needle bar 20A is supported by a sewing machine frame (not shown). A needle drive arm 40A for providing a driving force for the operation and a needle bar drive link 50A for connecting the needle bar 20A and the needle drive arm 30A are provided. The needle bar drive link 50A is provided between the needle bar 20A and the needle drive arm 40A. The first and second pin members 22A and 42Aa are rotatably connected to each other.
The needle bar drive mechanism 10A differs from the needle bar drive mechanism 10 mainly in that the needle bar 20A is supported only at the lower side instead of at the upper and lower two places, and the configuration of each part is slightly The difference is.
[0029]
The needle bar 20A is supported by the sewing machine frame so as to be able to reciprocate substantially vertically along only the needle bar lower metal 3 at the middle portion in the longitudinal direction. A sewing machine needle M is attached to the lower end of the needle bar 20A along its longitudinal direction, and the upper end is connected to one end of a needle bar drive link 50A so as to be rotatable mutually via a first pin member 22A. .
The needle drive arm 30A has one end connected to the needle drive shaft 30 in substantially the same manner as the needle drive arm 40 described above, and the other end unlike the needle drive arm 30 does not branch into a forked shape. On the other hand, the needle bar drive link 50A has one end branched in a forked shape, and the upper end of the needle bar 20A is arranged inside the needle bar drive link 50A and connected by the first pin member 22A. Further, the other end of the needle bar drive link 50A is also branched into a forked shape, and the rotating end of the needle drive arm 40A is disposed inside and connected by one second pin member 42Aa. .
[0030]
In such a configuration, when the needle bar drive link 40A reciprocates, the needle bar 20A moves up and down via the needle bar drive link 50A.
Further, the rotation of the first pin member 22A with respect to the needle bar 20A is restricted by a set screw, and the first pin member 22A slides on one end of the needle bar drive link 50A. The rotation of the second pin member 42Aa with respect to the needle drive arm 40A is restricted by a set screw, and the second pin member 42Aa slides on the other end of the needle bar drive link 50A. Each of the first and second pin members 22A and 42Aa is made of SKH51 as a base material and has a chromium nitride film formed on its outer peripheral surface, similarly to the above-described pin members 22 and 42a. Further, the needle bar drive link 50A is made of aluminum or its alloy as a base material, and a hard anodic oxide coating is formed on the sliding contact surface with each of the pin members 22A and 42Aa.
Therefore, even when a high surface pressure is applied between the needle bar drive link 50A and each of the pin members 22A and 42Aa and sliding is performed at a high speed as in the case of the lock sewing machine, the fretting wear is reduced. Demonstrate high durability.
[0031]
【The invention's effect】
According to the first aspect of the present invention, the sliding portion between the pin member and the needle bar drive link is formed by forming a chromium nitride film on the pin member side and forming a hard anodic oxide film on the needle bar drive link side. In addition, heat resistance, abrasion resistance, corrosion resistance, and oxidation resistance are improved, and the durability of parts where wear is likely to occur is improved. Therefore, it is possible to achieve oil-free sewing machine needle drive components, which were difficult to achieve due to its high speed and high surface pressure, even though oil-free was desired. Can be effectively avoided.
In addition, the durability of the lock sewing machine, in which the speed and the surface pressure of the structure for driving the sewing machine needle have been increased, has made it possible to realize lubrication-free due to its durability.
[0032]
Furthermore, since a porous layer is formed by forming a hard anodic oxide coating on the sliding surface of the needle bar drive link, grease is used on such a sliding surface, so that grease is applied to the surface of the porous layer that becomes the porous chamber. It is possible to hold. When the grease is held in the porous layer, the sliding between the pin member and the needle bar drive link can be smoothly performed, and the deterioration due to the heat generated by the sliding friction and the wear due to the sliding can be avoided. It is possible to extend the life of the drive link. Further, even when grease is used, no stain is generated due to oil leakage.
[0033]
According to the second aspect of the present invention, since the chromium nitride film is formed by the ion plating method, the film pressure can be reduced, the smoothing process after the film formation is not required, and the productivity can be improved. It is possible. In addition, since the pin member is not heated to a high temperature unlike the thermal spraying method, it is possible to effectively avoid a change or deterioration in the properties of the base material of the pin member, and to maintain a high durability.
Furthermore, the chromium nitride film formed by the ion plating method has high adhesion to the surface of the pin member, and prevents peeling and deterioration of the film due to sliding, and can further improve durability.
[0034]
According to the third aspect of the present invention, a ceramic film is formed on the sliding portion of the pin member and a hard anodic oxide film is formed on the needle bar drive link, so that the heat resistance and the heat resistance are higher than those of metals such as iron and aluminum. Abrasion, corrosion resistance and durability are improved. Therefore, it is possible to realize oil-free operation of the driving components of the sewing machine needle by the improvement of the durability, and it is possible to effectively avoid the generation of stains on the fabric and the surroundings.
Further, since the ceramics that form the coating are those proposed in the ion plating method, the same effects as those of the invention described in claim 2 can be obtained when the film is formed by the ion plating method. .
[0035]
According to a fourth aspect of the present invention, since the base material of the needle bar drive link is aluminum or its alloy having a low specific gravity, its own weight is reduced, and a pin member generated when the needle drive arm and the needle bar are driven at a high speed. Can be reduced. Therefore, it is possible to reduce the occurrence of deterioration and wear on the sliding surfaces of both the needle bar drive link and the pin member, and to prolong the life thereof even in an oilless environment.
[0036]
According to the fifth aspect of the present invention, since SKH is used as a steel material as a base material of the pin member, its characteristics are hardly changed or deteriorated even at a high temperature, and its strength is maintained even at the time of forming a ceramic film or sliding during use. However, the durability can be maintained even without lubrication.
[Brief description of the drawings]
FIG. 1 is a front view in which a part of a lock sewing machine according to an embodiment of the present invention is cut away.
FIG. 2 is a cross-sectional view taken along line XX of FIG.
FIG. 3 is an explanatory view showing a connected state of a needle drive arm, a needle bar, and a needle bar drive link disclosed in FIG. 1;
FIG. 4 is a diagram showing endurance test results of the present invention and another comparative example with respect to a pin member and a needle bar drive link.
FIG. 5 is an exploded perspective view showing another mechanical configuration example of the needle bar driving mechanism.
[Explanation of symbols]
1 sewing machine frame
Needle drive mechanism of 10,10A sewing machine
20, 20A Needle bar
22, 22A First pin member
40,40A needle drive arm
50,50A Needle bar drive link
51 Connecting part
52 Connecting part
M sewing needle

Claims (5)

A needle bar supported by a sewing machine frame to support a sewing needle at its distal end and reciprocally along its own longitudinal direction; a needle drive arm for applying a driving force for the reciprocating operation to the needle bar; A needle bar drive link connecting the bar and the needle drive arm,
The needle bar drive link is rotatably connected to both the needle bar and the needle drive arm by a pin member,
A ceramic coating film made of chromium nitride is formed on at least the sliding surface of each of the pin members with the needle bar drive link, wherein each of the pin members is formed of a steel material,
A needle bar drive mechanism for a sewing machine, wherein the needle bar drive link is formed of light metal and a hard anodic oxide coating is formed on at least a sliding surface of the needle bar drive link with the pin members. 2. The needle bar driving mechanism for a sewing machine according to claim 1, wherein the coating film of each of the pin members is formed by an ion plating method. A needle bar supported by a sewing machine frame to support a sewing needle at its distal end and reciprocally along its own longitudinal direction; a needle drive arm for applying a driving force for the reciprocating operation to the needle bar; A needle bar drive link connecting the bar and the needle drive arm,
The needle bar drive link is rotatably connected to both the needle bar and the needle drive arm by a pin member,
A coating film of a ceramic material is formed by an ion plating method on at least the sliding surface of each pin member with the needle bar drive link, wherein each pin member is formed of a steel material,
A needle bar drive mechanism for a sewing machine, wherein the needle bar drive link is formed of light metal and a hard anodic oxide film is formed on at least a sliding surface of the needle bar drive link with each of the pin members. 4. The needle bar drive mechanism for a sewing machine according to claim 1, wherein the light metal forming the needle bar drive link is aluminum or an alloy thereof. 5. The needle bar drive mechanism for a sewing machine according to claim 1, wherein a steel material forming each of said pin members is SKH.

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