JP3617038B2 - Manufacturing method of grooved plug - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a method for manufacturing a grooved plug that is detachably screwed to a bottom of an oil tank and plugged.
[0002]
[Prior art]
This type of grooved plug has a solid shaft portion having a screw on the outer periphery, a polygonal head portion provided at one end of the shaft portion, and a boundary portion between the head portion and the shaft portion. In use, the circumferential groove is provided with a gasket for preventing oil leakage and is screwed to the bottom of the oil tank in this state.
And as a manufacturing method thereof, a member comprising a solid shaft portion and a polygonal head portion provided at one end of the shaft portion is formed by forging, and then the head portion and the shaft portion are formed by cutting. A peripheral groove was formed at the boundary portion of this and a screw was formed at the outer periphery of the solid shaft portion.
[0003]
[Problems to be solved by the invention]
However, according to the manufacturing method described above, that is, when the circumferential groove is formed by cutting, it is very difficult to accurately form the circumferential groove between the head and the solid shaft portion. Since the width of the tool is narrow, a tool formed by cutting the tool has a thin blade edge. Therefore, the tool is easily broken or worn, which causes a reduction in work efficiency and an increase in cost. In addition, according to the cutting process, the fiber flow is cut at the circumferential groove portion, and the strength of the circumferential groove portion is lowered, and there is a disadvantage that the fracture is easily caused.
[0004]
Therefore, an object of the present invention is to provide a method for manufacturing a grooved plug that is easy to manufacture, has sufficient strength in the peripheral groove portion, and does not cause breakage of the tool during manufacturing .
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 of the present application includes a solid shaft portion having a screw on the outer periphery, a head portion having an outer periphery provided at one end of the shaft portion, and the head portion. As a method of manufacturing a grooved plug having a peripheral groove with a right-angled concave cross section provided at the boundary between the shaft and the shaft , first, one end of the cylindrical material is compressed by forging at the former forging station. Form an intermediate molded product with an outer diameter smaller than that of the other part, and then split the large diameter base of the intermediate molded product and the proximal end of the smaller diameter part at the subsequent forging station. The die is constrained in its shape, and only the remaining tip side of the intermediate molded product is forged with a punch with a molding hole to expand the diameter under the constrained state. A continuous groove having a concave shape with a right-angled cross section is formed.
[0007]
The invention described in claim 2 is characterized in that when the head is formed by forging, the outer periphery of the head is formed into a polygonal shape.
Furthermore, the invention described in claim 3 is characterized in that after the head is temporarily formed by forging, the outer periphery of the temporary head is forged into a polygonal shape in the next step.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention are described below. FIG. 1 and FIG. 2 show a grooved plug for drain provided on the bottom of an oil pan (container) for draining water. As shown in FIG. A solid shaft portion 2 having a screw 2a that can be screwed into a discharge port C with a screw hole B formed at the bottom of A on the outer periphery, and a hexagonal head that is provided at one end of the shaft portion 2 A portion 3 and a peripheral groove having a right-angled concave section formed by plastic working by forging at the boundary between the head 3 and the shaft portion 2 are provided. The shape of the head 3 may be other polygonal shapes such as a gear shape and a serration shape in addition to the hexagonal shape.
[0009]
Moreover, in FIG. 1, the code | symbol 5 is exhibiting the ring shape with packing made from aluminum or copper etc. with which the said circumferential groove 4 is mounted | worn. Here, when the packing 5 is fitted and attached to the circumferential groove 4, for example, an appropriate press-type fitting machine (not shown) that press-fits the circumferential groove 4 while holding the packing 5 is used.
[0010]
An example of use of the grooved plug 1 will be described. As shown in FIG. 1, a discharge port C formed at the bottom of the oil pan A indicated by an imaginary line in a state in which a packing 5 is mounted in the circumferential groove 4 in advance. The solid shaft portion 2 having the screw 2a on the outer periphery is screwed into the screw hole B and used. In that case, since the packing 5 is tightly fitted in the circumferential groove 4, the packing 5 is shifted or moved to the screw 2 a side or inadvertently when the plug 1 is attached to the oil pan A by screwing. It can be easily and easily tightened without falling.
[0011]
In the case of this grooved plug, the circumferential groove 4 is formed not by cutting but by plastic working by forging. As a result, the manufacturing is easier than in the case of cutting, and there is no breakage of the tool at the time of manufacturing.In addition, the fiber flow of the material is not cut at the circumferential groove portion, and the circumferential groove portion is not cut. It suppresses strength reduction and is difficult to break.
[0012]
In the above-described embodiment, the drain grooved plug provided in the oil pan A has been described. However, the drain grooved plug is not limited to the drain grooved plug. Of course, it can be used for plugs for various purposes such as replacement plugs.
[0013]
Next, a manufacturing method of the grooved plug will be described.
FIG. 3 is a plan view showing a schematic configuration of the multi-stage forging machine used in this embodiment. The molding machine 10 has a die block on one surface of a work space 12 provided in the center of the main body 11. 13, a plurality of die units 14 a to 14 d are disposed on the die block 13, and a ram 15 that approaches and separates from the die block 13 is disposed on a surface facing the die units 14 a to 14 d. The punch units 16a to 16d are arranged so as to face the die units 14a to 14d respectively, and the die units 14a to 14d and the punch units 16a to 16d facing each other are provided with a plurality of forging stations S1 to S4. It is configured.
[0014]
And the cutter apparatus 17 is provided in the end of the said die block 13, and the raw material b shown in FIG. 4 is formed by cut | disconnecting the wire a to a predetermined dimension by this cutter apparatus 17. FIG. The raw material b is sequentially supplied to the forging stations S1 to S4 and subjected to a predetermined forging process, and then the outer peripheral surface of the solid shaft portion 2 is threaded, as shown in FIGS. Such a grooved plug 1 is formed.
[0015]
Among them, the first forging station S1 performs end face correction on the columnar material b as shown in FIG. 4 to form an intermediate molded product 1A as shown in FIG. Further, the second forging station S2 performs shaft drawing while turning the intermediate molded product 1A by 180 degrees in the horizontal direction to form the intermediate molded product 1B as shown in FIG. Further, the third forging station S3 turns the intermediate molded product 1B by 180 degrees in the horizontal direction to change the direction, thereby forming the intermediate molded product 1C as shown in FIG. Further, the fourth forging station S4 forge-molds the intermediate molded product 1C, and has a solid shaft portion 2 as shown in FIG. 8 and a hexagonal head 3 provided at one end of the shaft portion 2. And the final molded product 1D provided with the peripheral groove 4 formed in the boundary part of this head part 3 and the axial part 2 is formed.
[0016]
Next, among the stations of the forging machine 10, the fourth forging station S4 that constitutes a characteristic part of the present invention will be described in more detail.
[0017]
In the fourth forging station S4, a solid shaft portion 2 as shown in FIG. 8 is obtained from an intermediate molded product 1C having a shaft portion 2 ′ at one end and a small diameter shaft portion 3 ′ at the other end as shown in FIG. And a head 3 having a hexagonal outer periphery provided at one end of the shaft 2, and a peripheral groove having a right-angled concave cross section provided at the boundary between the head 3 and the shaft 2. The final molded product 1D is formed.
[0018]
As shown in FIG. 9, as the structure of the die unit 14d of the fourth forging station S4, a substantially cylindrical die case 22 is inserted and fixed to the die block 13 via a pressure receiving member 21 that receives a load from the front. A first support member 23 and a second support member 24 are fitted and fixed to the back side in the die case 22, and a pair of split dies 25 and 25 are moved forward and backward in the front portion of the die case 22. Is inserted to be movable. The second support member 24 is provided with a third support member 26. A ring-shaped fourth support member 27 is slidably inserted back and forth on the front side of the support member 26. Yes.
[0019]
The rear surfaces of the split dies 25, 25 are supported by a substantially cylindrical stripper 28 slidably fitted to the die case 22, and the rear surface of the stripper 28 having a large diameter is a ring. The fourth support member 27 is urged forward by a plurality of coil springs 29 housed in the third support member 26. A center pin 31 is inserted into the stripper 28, the rear end of the center pin 31 is supported by the second support member 24, and the front end thereof extends toward the divided dies 25 and 25. In this case, the forward movement of the divided dies 25, 25 is regulated at the position shown in FIG. 9 by the stopper plate 32 fixed to the front surface of the die unit 22 with bolts. Further, the center pin 31 is pushed forward through the push pin 33 and the second support member 24 by the operation of a knockout mechanism (not shown) when the final molded product 1D is discharged.
[0020]
Next, as a structure of the punch unit, a punch holder 34 is fixed to the ram 15, and a punch 35 is fitted and fixed in the holder 34, and a center portion of the punch 35 can be slid in the front-rear direction. A pin 36 is inserted into the.
[0021]
10 and 11 show the configuration of the die case 22 and the divided dies 25 and 25 that are opened in the case 22. That is, the pair of split dies 25, 25 is a solid composed of two surfaces whose outer shapes are parallel to each other and two inclined surfaces which are orthogonal to these surfaces and the distance between them becomes narrower toward the back side. The inner surface of the die case 22 is divided into two parts in a cross-section perpendicular to the two parallel planes, corresponding to the above three-dimensional body, the two parallel planes 22a and 22a, and perpendicular to these planes and on the far side. It fits in the space comprised by slope 22b, 22b from which a mutual space | interval becomes narrow so that it reaches.
[0022]
At the center of the parallel two surfaces 22a and 22a on the inner surface of the die case 22, the guide protrusions 37 and 37 each having both sides in a triangular shape parallel to the two inclined surfaces 22b and 22b on the inner surface of the die case 22 are provided. Is provided. On the other hand, on the surfaces 25a and 25a facing the parallel two surfaces 22a and 22a of the inner surface of the die case 22 of the divided dies 25 and 25, guide recesses 25b and 25b that fit into the guide protrusions 37 and 37, respectively, are provided. Thus, the divided dies 25, 25 can be moved back and forth in the axial direction along the inner surface thereof without rotating within the die case 22.
[0023]
Further, the split surfaces of the split dies 25, 25 are formed with recesses 25c, 25c facing each other, so that the split dies 25, 25 are separated in the direction of the two inclined surfaces 22b, 22b of the inner surface of the die case 22. Energizing coil springs 38 and 38 are respectively provided. In addition, on the split surfaces of the split dies 25 and 25, molding recesses 25d and 25d having shapes corresponding to the final molded product 1D are provided, respectively.
[0024]
Next, a process in which the intermediate product 1C shown in the fourth forging station S4 is formed into a final molded product 1D shown in FIG. 8 will be described.
As shown in FIG. 9, when the ram 15 moves forward with the intermediate product 1C being fed in front of the die unit 14d of the fourth forging station S4 by a material transfer device (not shown), first, the punch The tip of the pin 36 of the unit 16d pushes the intermediate product 1C toward the die unit, so that the intermediate product 1C is at the tip of the center pin 31 positioned at the center of the two divided dies 25, 25 in the die unit 14d. It is inserted so that it may contact.
[0025]
Further, as the ram 15 further advances, as shown in FIG. 12, the tip of the punch 35 comes into contact with the split dies 25, 25, and the split dies 25, 25, the stripper 28, and the fourth supporter 27 are resisted against the coil spring 29. Then, it is pushed into the back side of the die case 22. At this time, since the outer peripheral surface of each of the divided dies 25 and 25 and the inner periphery of the front end of the die case 22 are each a pyramidal surface whose diameter decreases toward the back side, each of the divided dies 25 and 25 is attached to the coil springs 38 and 38. The two die halves 25 and 25 are gathered together while being guided by the pyramid surface of the die case 22 against the force. Thereby, as shown in FIG. 12, the outer peripheral surface of the intermediate product 1C in contact with the center pin 31 is fastened by the inner peripheral surfaces of the divided dies 25, 25, and these divided dies 25, 25, punch 35 and pin Thus, a final finished product 1D having a solid shaft portion 2, a head portion 3 and a circumferential groove 4 is manufactured as shown in FIG.
[0026]
In this case, the head 3 and the circumferential groove 4 are formed by expanding the diameter of the distal end portion while restraining the proximal end portion of the small diameter portion of the intermediate product 1C by the projections 37, 37 on the inner surfaces of the split dies 25, 25. Therefore, the fiber flow of the material is not cut in the range from the solid shaft portion 2 to the head portion 3 via the circumferential groove 4.
[0027]
When the final molded product 1D as described above is manufactured in the cavity, the punch unit 16d moves backward from the die block side together with the ram 15, so that the divided dies 25 and 25 in the die case 22 are moved by the coil spring 29. While being pushed forward through the fourth support 27 and the stripper 28, they are separated from each other by the coil springs 38, 38 shown in FIG. 10, and the entire diameter is expanded, and the final molding 1D is released. Then, when the center pin 31 moves forward thereafter, the final molding 1D is discharged out of the die case 22. Thereafter, in a subsequent step, the screw 2a is formed on the outer periphery of the solid shaft portion 2, and thereby the grooved plug 1 as the final product shown in FIGS. 1 and 2 is formed.
[0028]
In the above-described embodiment, the die of the fourth forging station S4 is composed of two surfaces 25a and 25a whose outer shapes are parallel to each other and two inclined surfaces that are orthogonal to these surfaces and the distance between them becomes narrower toward the back side. And a recess 25c for forming the final molded product at the center of both divided dies 25, 25. , 25c, and the inner surface of the space of the die case 22 in which the divided dies 25, 25 are accommodated, corresponding to the solid, the two parallel surfaces 22a, 22a and the surfaces 22a, 22a are orthogonal to each other, In addition, since it is configured by two inclined surfaces 22b and 22b whose intervals become narrower toward the back side, both divided dies 25 and 25 are held in a predetermined direction in the die case 22.
[0029]
Further, the mold opening means of the divided dies 25, 25 is provided at the center of two parallel surfaces 22a, 22a constituting the inner surface of the space of the die case 22, and both sides constitute the inner surface of the space of the die case 22. The guide projections 37, 37 each having a triangular shape parallel to the two inclined surfaces, and the guides provided on the surfaces of the divided dies 25, 25 facing the two parallel surfaces of the die case 22 are fitted to the projections 37, 37. Since it comprises the hollow parts 25b and 25b for use, when the division | segmentation dies 25 and 25 are extruded, it can be made to open | release reliably.
[0030]
In the described embodiment, the final molded product 1D is immediately molded from the intermediate molded product 1C at the fourth station A4. However, the present invention is not limited to this structure. For example, as shown in FIG. In the fourth forging station (not shown), an intermediate molded product 1C ′ having a temporary head 3 ″ and a circumferential groove 4 ″ is formed on one end side of the shaft portion 2 ″, and then the fifth forging station. The final molded product 1D may be formed in several stages by forging the outer periphery of the temporary head 3 ″ into a polygonal head 3 (not shown).
[0031]
As described above, according to the present invention, the solid shaft portion having a screw on the outer periphery, the outer periphery provided at one end of the shaft portion is a polygonal head portion, and the boundary portion between the head portion and the shaft portion. A grooved plug provided with a circumferential groove having a right-angled cross section provided can be manufactured by forging , and a cutting tool with a thin blade edge for forming the circumferential groove as in the prior art becomes unnecessary, and the tool Thus, a reduction in work efficiency due to breakage of the steel or early wear is avoided. In addition, in the production thereof, in particular, at the former-side forging station, one end of the cylindrical material is reduced in diameter by forging to form an intermediate molded product having an outer diameter smaller than that of the other part. At the forging station, the large-diameter base portion of the intermediate molded product and the proximal end side of the subsequent small-diameter portion are constrained to the shape by a split die, and the remaining part of the intermediate molded product is maintained under the restraint condition. Only the tip side is forged with a punch with a forming hole to expand the diameter, so that the head and the peripheral groove with a right-angled concave section following it are formed on the tip side. A groove with a right-angled concave cross-section can be formed with high precision by plastic working. As a result, a grooved plug is obtained in which the fiber flow of the material is not cut in the circumferential groove with a right-angled cross-section. Actively suppresses the decrease in strength Rukoto can.
[Brief description of the drawings]
FIG. 1 is a front view of a grooved plug according to an embodiment of the present invention.
FIG. 2 is a plan view showing a usage state of the grooved plug.
FIG. 3 is a schematic plan view of a multistage forging machine used in the method for manufacturing a grooved plug according to the embodiment of the present invention.
FIG. 4 is a side view showing the shape of a material processed by the molding machine.
FIG. 5 is a side view showing the shape of an intermediate molded product molded at the first forging station of the molding machine.
FIG. 6 is a side view showing the shape of an intermediate molded product molded at the second forging station of the molding machine.
FIG. 7 is a side view showing the shape of an intermediate molded product molded at the third forging station of the molding machine.
FIG. 8 is a side view showing the shape of the final molded product molded at the fourth forging station of the molding machine.
9 is a cross-sectional view showing the configuration of a fourth forging station for carrying out the method of the present invention of the molding machine of FIG.
FIG. 10 is a front view of the main part of the die unit as seen along the line of FIG.
11 is a cross-sectional view of the main part of the die unit taken along the line II in FIG. 10;
FIG. 12 is a cross-sectional view showing a molding state when the punch unit is advanced in the molding machine.
FIG. 13 is a side view showing the shape of an intermediate molded product showing another embodiment.
[Explanation of symbols]
1 Slotted plug 2 Solid shaft portion 2a Screw 3 Head 3 "Temporary head 4 Circumferential groove 25 Split die

Claims (3)

A solid shaft portion having a screw on the outer periphery, a head portion having a polygonal outer periphery provided at one end of the shaft portion, and a circumferential groove having a right-angled concave section provided at a boundary portion between the head portion and the shaft portion As a manufacturing method of a grooved plug equipped with an intermediate part, first, an intermediate molded product is formed by reducing one end of a cylindrical material by forging at the former side of the forging station so that the outer diameter is smaller than other parts. Next, at the subsequent forging station, the large-diameter side base portion of the intermediate molded product and the base end side of the small-diameter portion that follows it are constrained to the shape by the split die, and the intermediate state is maintained under the constrained state. A groove characterized in that only the remaining tip side of the molded product is formed by forging with a punch with a molding hole to expand the diameter, thereby forming a head and a concave groove with a right-angled cross section at the tip. Method of manufacturing a plug. The method for manufacturing a grooved plug according to claim 1, wherein when the head is formed by forging, the outer periphery of the head is formed into a polygonal shape. 3. The method for manufacturing a grooved plug according to claim 2, wherein after the head is temporarily formed by forging, the outer periphery of the temporary head is forged into a polygonal shape in the next step .

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