JP4108190B2 - Actuator fingers for circular knitting machines - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of braiding machines, and particularly relates to actuator fingers for circular knitting machines.
[0002]
[Prior art and problems to be solved by the invention]
In a circular knitting machine, braiding can be performed while forming a desired pattern on an obtained knitted fabric by controlling the movement path of the knitting needle by appropriately bringing an actuator finger into contact with the knitting needle in a needle selection mechanism. Such a movement path of the knitting needle is controlled by engaging each of a large number of actuator fingers with an action portion of the actuator and controlling the actuator in a desired manner by an electronic computer.
[0003]
The actuator finger includes a first part adapted to a tip (acting part) of an actuator using a piezoelectric element that operates in response to an electric signal controlled by an electronic computer and receives a driving force from the acting part, and the first part And a second portion that controls the traveling movement path by appropriately contacting the knitting needle.
[0004]
As a method for producing such an actuator finger, a green molded body having a desired shape corresponding to a mold is formed by molding a molding material obtained by mixing metal powder with a binder containing a thermoplastic plastic with an injection molding machine. Next, a metal injection molding method (MIM method) in which the binder plastic is burned or sublimated by heat-treating the green molded body and the metal powders in the green molded body are sintered can be used. According to this, although there is dimensional shrinkage with respect to the green molded body, it is possible to obtain a product (actuator finger) made of a metal sintered body substantially similar to the green molded body. This method has an advantage that a large amount of product can be manufactured in a short time as compared with a method of machining a bulk metal material by cutting or the like to obtain a desired shape.
[0005]
By the way, since the first portion of the actuator engaging portion that engages with the actuator needs to accurately follow the minute displacement of the acting portion of the actuator, extremely high dimensional accuracy is required. Is not required. On the other hand, the head (knitting needle contact portion) of the second portion that comes into contact with the knitting needle requires high hardness in order to minimize wear and increase the life against frequent abrasion (contact) of the knitting needle. Is done.
[0006]
Thus, when an actuator finger having a plurality of parts with different requirements for hardness and other characteristics is formed of a metal sintered body, if there is a metal material that satisfies all the characteristics required for each part, It is preferable to use it for a part (that is, the entire actuator finger is made of the same material). In reality, however, that is difficult.
[0007]
That is, the high hardness required for the head of the second portion of the actuator finger can be realized by carburizing and quenching the sintered body. However, when the entire actuator finger is made of such a material and carburizing and quenching is performed to make the entire product high in hardness, if the first part is deformed during carburizing and quenching, the correction is corrected. Causes the disadvantage of becoming extremely difficult.
[0008]
Further, the addition of the carburizing and quenching process causes a disadvantage that the manufacturing process is complicated and the cost is increased by increasing the number of steps.
[0009]
Therefore, the present invention provides an actuator finger that can be obtained without requiring a quenching step and includes a second portion having a high hardness and a first portion having a low hardness that can easily achieve high dimensional accuracy. It is intended to do.
[0010]
[Means for Solving the Problems]
According to the present invention, the above object is achieved as follows:
An actuator finger for a circular knitting machine, connected to the actuator operating portion of the needle selection mechanism of the circular knitting machine, for controlling the movement path of the knitting needle in contact with the knitting needle,
A first portion having an actuator engaging portion that engages with the actuator; and a second portion having a knitting needle contact portion that contacts the knitting needle, wherein the first portion is a first metal. The second part is made of a sintered body of a second metal material different from the first metal material, and the second part has a hardness higher than that of the first part. ing,
Actuator fingers for circular knitting machines,
Is provided.
[0011]
In one aspect of the present invention, it has a through hole for receiving a pin, and the through hole is located near the actuator engaging portion between the knitting needle contact portion and the actuator engaging portion. is doing.
[0012]
In one aspect of the present invention, the through hole is provided in the second portion, and the first portion is provided between the through hole of the second portion and the actuator engaging portion of the first portion. A joint portion between the portion and the second portion is interposed.
[0013]
In one aspect of the present invention, the actuator engaging portion is configured to sandwich the action portion of the actuator.
[0014]
In one aspect of the present invention, the first portion has a hardness Hmv of 80 to 250, and the second portion has a hardness Hmv of 600 or more.
[0015]
In one embodiment of the present invention, the first metal material has a carbon content of 0.2% or less, and the second metal material has a carbon content of 0.5% or more.
[0016]
In one aspect of the present invention, the first material is stainless steel or Fe-2 to 8% Ni, and the second material is alloy tool steel, carbon tool steel, or high speed steel.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a side view showing an embodiment of an actuator finger for a circular knitting machine according to the present invention, and FIG. 2 is an XX ′ sectional view thereof.
[0019]
1-2, the code | symbol 2 shows a 1st part and the code | symbol 4 shows a 2nd part. As shown in FIGS. 1 and 2, the first portion 2 has a U-shaped cross section that is open downward and extends along a direction orthogonal to the XX ′ direction (vertical direction). (A groove width is, for example, 2.0 mm) 22, and a pair of legs 24 are formed so as to form the groove 22. The second portion 4 includes a base portion 44 formed with a substantially square through hole (minimum inner diameter is 1.7 mm, for example) 42 extending in parallel with the groove 22, a neck portion 46, and a head portion supported by the neck portion. 48. Reference numeral 6 denotes a joint surface between the first portion 2 and the second portion 4.
[0020]
The first portion 2 is made of a sintered body of a first metal material having a hardness Hmv of 600 or more, and the second portion 4 is made of a sintered body of a second metal material having a hardness Hmv of 80 to 250. The first metal material is, for example, stainless steel (SUS316L, SUS304L, etc.) having a carbon content of 0.2% or less, or Fe-2 to 8% Ni, and the second metal material is, for example, a carbon content of 0.5% or more. Alloy tool steel (such as SKD11), carbon tool steel (such as SK3) or high speed steel (such as SKH3).
[0021]
FIG. 3 is a cross-sectional view showing a usage state of the actuator finger of the present embodiment. A pin 10 having a circular cross section that functions as a rotation center support shaft passes through the through hole 42. The pin 10 is disposed in the needle selection mechanism of the circular knitting machine, and fits with the minimum inner diameter of the through hole 42 and a small clearance. Therefore, the actuator finger can be rotated around the pin 10. On the other hand, the upper end (action part) of the piezoelectric element actuator 12 is inserted into the groove 22 from below with a minute clearance. The lower end of the actuator 12 is fixed to the needle selection mechanism of the circular knitting machine, and is operated by receiving a required electrical signal in association with a number of other actuator fingers under the control of an electronic computer. Thereby, the upper end of the actuator 12 can be displaced in the left-right direction in FIG. Along with this, the foot 24 adapted to sandwich the actuator action part receives a driving force, the actuator finger rotates around the pin 10, and the head 48 is shown in FIG. It can be displaced in the left-right direction. This displacement of the head 48 is equivalent to an expansion of the displacement of the actuator acting part because the distance from the pin 42 is larger than the distance from the pin to the actuator acting part. The maximum displacement of the head 48 is, for example, about 0.5 mm on one side and about 1 mm on both sides.
[0022]
A knitting needle of a circular knitting machine (not shown) can come into contact with the head 48 during the movement, and the movement path after the contact is released is controlled according to the magnitude of the displacement of the head. The foot portion 24 constitutes an actuator engaging portion, and the head portion 48 constitutes a knitting needle contact portion.
[0023]
The actuator fingers as described above are manufactured as follows using a metal injection molding method.
[0024]
First, a first molding material containing a first metal material for the first portion 2 is obtained. This first molding material is, for example, a mixture of SUS316L powder with polyethylene as a binder, paraffin wax and stearic acid. The amount of binder added is, for example, 45% by volume.
[0025]
Apart from this, a second molding material comprising a second metal material for the second part 4 is obtained. This second molding material is, for example, a mixture of SKD11 powder with polyethylene as a binder, paraffin wax and stearic acid. The binder addition amount is, for example, 43% by volume.
[0026]
The first molding material and the second molding material are subjected to a two-color molding machine, and first, the second molding material is molded by injection molding into the cavity for the second portion of the molded body corresponding to the second portion 4. A body second part is formed. Next, the movable mold member of the mold apparatus is moved to form a cavity for the first portion of the molded body corresponding to the first portion 2, and the first molding material is injection-molded therein to form the molded body first. One part is formed. Thereby, the green molded object which consists of a molded object 1st part and a molded object 2nd part is obtained. The above steps are continuously performed in the two-color molding machine with a step of moving the mold apparatus from a position corresponding to the injection port of the second molding material to a position corresponding to the injection port of the first molding material. Done.
[0027]
By heating the green molded body obtained as described above, the binder is removed from the green molded body and the metal powder is sintered to obtain an actuator finger as shown in FIGS. This heat treatment can be performed in a reduced pressure heating furnace, for example, according to a temperature curve as shown in FIG.
[0028]
That is, first, the temperature is raised from room temperature to 100 ° C. over 30 minutes from time 0 to T ₁ , and this temperature is maintained for 4 hours from time T ₁ to T ₂ . During this period, the inside of the heating furnace is depressurized to about 10 ⁻⁵ Torr in order to promote the removal of the paraffin wax from the molded body and its removal outside the system.
[0029]
Next, the temperature is raised to 400 ° C. at a temperature gradient of 0.5 ° C./min from time T ₂ to T ₃ , and this temperature is maintained for 1 hour from time T ₃ to T ₄ .
[0030]
Next, the temperature is raised to 500 ° C. at a temperature gradient of 1 ° C./min from time T ₄ to T ₅ , and this temperature is maintained for 2 hours from time T ₅ to T ₆ .
[0031]
Thus, the binder burns.
[0032]
Next, the temperature is raised to 1100 ° C. at a temperature gradient of 10 ° C./min from time T ₆ to T ₇ , and this temperature is maintained for 1 hour from time T ₇ to T ₈ .
[0033]
Next, the temperature is raised to 1230 ° C. with a temperature gradient of 10 ° C./min from time T ₈ to T ₉ , and this temperature is maintained for 4 hours from time T ₉ to T ₁₀ .
[0034]
Thereby, metal powders are sintered.
[0035]
Next, in a heating furnace, over 4 hours from the time T ₁₀ until T ₁₁ quenched to room temperature.
[0036]
From time T ₂ to T ₁₁ , the inside of the heating furnace is kept under a reduced pressure of about 10 Torr by introducing nitrogen gas.
[0037]
According to the above process, in the first molding material containing the first metal material having a relatively high melting point of about 1400 ° C., the binder content is relatively high at 45% by volume, and the melting point is about 1240 ° C. In the second molding material containing the relatively low second metal material, the shrinkage rate of the first part of the molded body is reduced by sintering heat treatment at a peak temperature of 1230 ° C. by relatively reducing the binder content to 43% by volume. And the contraction rate of the second portion of the molded body are equal, and the residual stress in the vicinity of the joint surface 6 between the first portion 2 and the second portion 4 can be sufficiently reduced.
[0038]
Further, in the heat treatment, from time T ₆ to T _7, by rapidly heating, the occurrence of uneven distribution of heat at the time of sintering and minimized to achieve a uniform contraction (approximately 18% shrinkage) Abnormal deformation can be prevented.
[0039]
The effect of preventing such deformation is that after the first stage for removing the binder (ie, from time 0 to time T ₆ ), the second stage for sintering the metal material powder (ie, from time T _6). It can be obtained by increasing the temperature at a rate of 8 ° C./min or higher at time T ₁₁ ).
[0040]
This effect is particularly effective when it is performed in a range including a temperature of 800 to 1050 ° C. (a range from time T ₆ to time T ₇ in FIG. 4). This is because the compaction of the molded body is most severely contracted within this temperature range. Therefore, it is possible to suppress the generation of a non-uniform distribution of heat as much as possible by performing rapid heating within this range. This is because it is extremely effective in realizing proper shrinkage and preventing abnormal deformation.
[0041]
The first stage is preferably carried out in a range up to a temperature of 550 ° C. or less, and the rate of temperature increase in this first stage is preferably 3 ° C./min or less in order to perform debinding well. .
[0042]
The actuator fingers obtained as described above can be used without carburizing and quenching because the hardness of the second portion 4 is Hmv 720 to 830 (the second portion 4 constituting the second portion 4). Since the metal material 2 has a carbon content of 0.5% or more, the hardness of the second portion 4 is sufficiently improved by the quenching effect in the process of cooling in the furnace). Further, since there is no need for carburizing and quenching, there is no possibility of deformation due to carburizing and quenching work, and the dimensional accuracy of the first portion 2 is good. Furthermore, by performing the heat treatment under reduced pressure and in a nitrogen atmosphere, the first portion 2 has a low carbon and oxygen content and a hardness of Hmv 110 to 140, so that the dimensional accuracy can be further improved as necessary. Even when performing correction (for example, correction of the width of the groove 22), correction work by pressing or cutting is easy (the first metal material constituting the first portion 2 has a carbon content of 0.2% or less). Therefore, the first portion 2 has little improvement in hardness due to the quenching effect in the process of cooling in the furnace. In order to perform correction by pressing deformation, Hmv 150 or less is preferable, and in order to perform correction by cutting, Hmv 250 or less is preferable.
[0043]
In the above embodiment, the through hole 42 for receiving the pin 10 is provided in the second portion 4 near the joint portion with the first portion, and the joint between the first portion and the second portion is provided. The area of the surface 6 can be increased, which is advantageous. However, in the present invention, an embodiment in which the joint surface between the first part and the second part is arranged as indicated by reference numeral 8 in FIG. 2 and the through hole 42 is provided in the first part is also possible. is there.
[0044]
【The invention's effect】
As described above, according to the present invention, there is provided an actuator finger including a high hardness second portion and a low hardness first portion that can easily achieve high dimensional accuracy without a quenching step.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of an actuator finger for a circular knitting machine according to the present invention.
FIG. 2 is a cross-sectional view taken along the line XX ′ of FIG.
FIG. 3 is a cross-sectional view showing a usage state of an embodiment of an actuator finger for a circular knitting machine according to the present invention.
FIG. 4 is a graph showing a temperature curve of heat treatment when manufacturing an embodiment of an actuator finger for a circular knitting machine according to the present invention.
[Explanation of symbols]
2 First portion 4 Second portion 6, 8 Joint surface 22 Groove 24 Foot (actuator engaging portion)
42 Through-hole 44 Base 46 Neck 48 Head (knitting needle contact part)

Claims (7)

An actuator finger for a circular knitting machine, connected to the actuator operating portion of the needle selection mechanism of the circular knitting machine, for controlling the movement path of the knitting needle in contact with the knitting needle,
A first portion having an actuator engaging portion that engages with the actuator and having a hardness Hmv of 80 to 250, and a second portion having a knitting needle contact portion that contacts the knitting needle and having a hardness Hmv of 600 or more. The first portion is made of a sintered body of a first metal material having a carbon content of 0.2% or less , and the second portion has a lower melting point than the first metal material and a carbon content. An actuator finger for a circular knitting machine, comprising a sintered body of a second metal material of 0.5% or more .   It has a through hole for receiving a pin, and the through hole is located near the actuator engaging portion between the knitting needle contact portion and the actuator engaging portion. The actuator finger for circular knitting machines according to claim 1.   The through hole is provided in the second part, and the first part and the second part are between the through hole of the second part and the actuator engaging portion of the first part. An actuator finger for a circular knitting machine according to claim 2, characterized in that a joint portion is interposed.   The actuator finger for a circular knitting machine according to any one of claims 1 to 3, wherein the actuator engaging portion is configured to sandwich an action portion of the actuator. The first metal material is stainless steel or Fe-2 to 8% Ni, and the second metal material is alloy tool steel, carbon tool steel or high speed steel . The actuator finger for circular knitting machines according to any one of 4 above. The circular knitting machine actuator finger includes: a first molding material including the first metal material powder and a binder; and the second metal material powder and a binder having a lower content than the first molding material. By heating the green molded body obtained by molding the second molding material containing two colors, the binder is removed from the green molded body and the powders of the first and second metal materials are sintered. It is what was obtained, The actuator finger for circular knitting machines in any one of Claims 1-5 characterized by the above-mentioned. A method for producing an actuator finger for a circular knitting machine according to any one of claims 1 to 5,
A first molding material containing a powder of the first metal material and a binder, and a second molding material containing a powder of the second metal material and a binder having a lower content than the first molding material. Color molding to obtain a green molded body composed of a molded body second portion corresponding to the second portion and a molded body first portion corresponding to the first portion,
By heating the green molded body, the binder is removed from the green molded body and the powders of the first and second metal materials are sintered.
A method for manufacturing an actuator finger for a circular knitting machine.

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