JP3228548U - Closing plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plug for closing a plug so as to obtain a geometrical tolerance flatness for preventing oil bleeding without cutting at a bottom surface portion of a hexagonal head integrally formed with a shaft portion. SOLUTION: A shaft portion 2 having a screw on the outer circumference and a head portion 3 integrally provided at one end of the shaft portion having a hexagonal outer circumference are provided, and a central shaft portion 31 and a center thereof are provided on the upper surface of the head portion. A geometry for preventing oil bleeding is formed on the bottom surface of the head while forming a driving recess 32 having a small hexagonal shape that matches the contour shape of the head in the remaining portion excluding the shaft portion. An annular flat seat surface 33 having a tolerance flatness was formed. [Selection diagram] Fig. 4

Description

The present invention mainly relates to a plug that can be detachably closed to the bottom of an oil tank.

Conventionally, this type of plug is provided at, for example, a shaft portion having a screw on the outer circumference, a head portion provided at one end of the shaft portion having a hexagonal outer circumference, and a boundary portion between the head portion and the shaft portion. A plug body with a peripheral groove is formed, and when in use, a packing for preventing oil leakage, which is made of a separate member, is attached to the peripheral groove and screwed to the bottom of the oil tank to close the plug. It has been done.
In addition, as a manufacturing method of the plug main body, a rod-shaped blank is press-molded by a multi-stage pressure forming machine to integrally form a plug molded body consisting of a shaft portion and a hexagonal head in order to mass-produce the plug. By cutting, a peripheral groove for mounting the packing was formed at the boundary between the head and the shaft of the plug molded body, and a screw was further formed on the outer periphery of the shaft.

By the way, as described above, in the case of a plug molded body in which the shaft portion and the hexagonal head are simply pressed according to the contour shape by the multi-stage pressure forming machine, the hexagonal head is formed during the pressing. The bottom surface (seat surface) of the portion will be wavy due to sink marks after molding. As a result, the geometrical tolerance flatness for preventing oil bleeding cannot be obtained at the bottom surface portion of the head, and there is a problem that oil oozes out from the wavy bottom surface portion.

Therefore, conventionally, after the pressure forming as described above, a peripheral groove for mounting a packing for preventing oil bleeding is formed at the boundary between the head and the shaft by special cutting, and the peripheral groove is formed. After the packing is fitted and attached, the plug is screwed onto the bottom of the oil tank to close the plug, and the packing prevents oil from seeping.

However, in the case of a plug that forms a peripheral groove and attaches a packing in this way, it is complicated and troublesome to form a peripheral groove at the boundary between the head and the shaft as a post-process after the pressure molding of the plug molded body. There is a problem that a cutting process is required, and a troublesome fitting operation of the packing into the peripheral groove is required.

In addition, as another means of preventing oil bleeding from the bottom part that undulates due to the sink mark on the head, a thin flat washer made of copper or aluminum is sandwiched between the oil tank and the drain plug to form the oil tank and the drain plug. It is known that the oil is prevented from bleeding by eliminating the gap.
However, even in this case, the adhesion at the bottom surface is deteriorated due to the wavy sink marks, and due to this, the phenomenon that the oil oozes even when tightened with a strong torque still remains, and it is difficult to adopt.
Therefore, as a means of resolving oil bleeding, it is necessary to remove the wavy sink marks on the seat surface on the bottom surface. Therefore, after the plug molding, the bottom surface portion on the hexagonal head is specially used as a post-process. The current situation is that it is necessary to perform complicated and time-consuming high-precision cutting on the seat surface.

Therefore, in order to solve the above-mentioned problem, the present invention devises the upper surface shape of the polygonal head to prevent oil bleeding on the bottom surface of the polygonal head integrally formed with the shaft portion. Providing a high-quality, inexpensive plug that is formed so that flatness can be obtained, eliminates the need for special cutting as in the past, and has the function of preventing oil from seeping out only by pressure molding. Make it an issue.

The invention according to claim 1 of the present application includes a shaft portion having a screw on the outer periphery and a head portion integrally provided at one end of the shaft portion having a polygonal outer circumference, while the upper surface of the head portion has a center. A shaft portion and a recessed portion having a small polygonal shape that matches the contour shape of the outer circumference of the head are formed in the remaining portion excluding the central shaft portion, and the bottom surface portion of the head is formed. It is characterized in that an annular flat seat surface having a geometrical tolerance flatness for preventing oil bleeding is formed.

In the invention according to claim 2 of the present application, in addition to the configuration according to claim 1, the central shaft portion on the upper surface of the head is formed in a circular shaft shape, and the driving recess portion is the outer circumference of the central shaft portion. It is characterized in that it is formed from near the outer periphery of the head, and is formed in a tapered shape so that the central axis side of the driving recess is deeper and gradually becomes shallower toward the outer periphery of the head.

The plug of the present invention has a small hexagonal shape similar to the hexagonal shape of the outer circumference of the head, for example, with the central shaft portion on the upper surface of the head having a hexagonal shape and the central shaft portion removed as described above. In addition to the formation of the driving recessed portion, the bottom surface of the head is formed with an annular flat flat seat surface having a geometrical tolerance flatness for preventing oil bleeding. While it is possible to eliminate the need for special cutting processing, it is possible to reliably prevent oil from seeping out on the annular flat seat surface formed on the bottom surface of the head. In addition, mass production by a multi-stage pressure forming machine is easy and easy, and can be manufactured at low cost.

Further, the central shaft portion on the upper surface of the head is formed in a circular shaft shape, the driving recess portion is formed from the outer periphery of the central shaft portion to the vicinity of the outer circumference of the head, and the central shaft portion side of the driving recess portion is formed. If the structure is formed in a tapered shape so as to be deeper toward the outer peripheral side of the head, for example, when a hexagonal driven recess is formed on the upper surface of the hexagonal head by driving, the center is formed. The thick portion around the shaft portion can be effectively escaped to the outer peripheral side and plastically deformed smoothly without difficulty to perform heading molding with high accuracy. As a result, it is possible to remarkably improve the geometrical tolerance flatness of the bottom surface portion that becomes the flange of the head, that is, the annular flat seat surface, due to this hexagonal driving process, and it is possible to reliably prevent oil from seeping out. it can.

It is a front view which shows the closing plug which concerns on this invention. It is the same plan view. It is the same bottom view. FIG. 2 is a sectional view taken along line AA of FIG. FIG. 2 is a cross-sectional view taken along the line BB of FIG. It is a cross-sectional explanatory view which shows the molding state of the intermediate molded product of the plug which is molded by a multi-stage pressure forming machine. It is a cross-sectional explanatory view which shows the molding state of the final molded product of the plug closing plug molded by the multi-stage pressure forming machine.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 3 show a plug according to the present invention, and the plug (drain plug) 1 can be screwed into a screw holed outlet formed at the bottom of an oil tank (not shown). It includes a bottomed tubular shaft portion 2 having a screw 21 on the outer circumference, and a head portion 3 integrally provided at one end of the shaft portion 2 and having a hexagonal outer circumference.

Then, on the upper surface of the head 3, as shown in FIGS. 2 to 5, a circular central shaft portion 31 and a small portion that matches the contour shape of the head 3 on the remaining portion excluding the central shaft portion 31. A hexagonal driven recess 32 is formed, and an annular flat seat surface 33 having a geometrical tolerance flatness for preventing oil bleeding is formed on the bottom surface portion serving as a flange of the head 3. Has been done. In that case, the annular flat seat surface 33 is arranged so as to substantially correspond to the driving recessed portion 32 in the vertical direction so as to be formed at the same time when the driving recessed portion 32 is formed by driving.

The driving recess 32 is formed from the outer periphery of the central shaft portion 31 to the vicinity of the outer periphery of the head 3, and the central shaft 31 side of the driving recess 32 is deeper and gradually shallower toward the outer periphery of the head 3. It is formed in a tapered shape so as to be.

In the figure, reference numerals 34 ... 34 are angular edge portions that rise upward around the hexagonal outer circumference of the head.

As shown in FIGS. 6 and 7, the closing plug configured as described above has the central shaft portion and the head integrally integrated from one blank by a plurality of consistent pressing processes by the horizontal multi-stage pressure forming machine 10. Manufactured by molding.

Specifically, as shown in FIG. 6, in the first squeezing station S1 provided with the die 12 having the forming pin 11 at the center and the columnar punch 13 in the horizontal multi-stage squeezing molding machine 10, the columnar punch 13 An intermediate molded product A in which a columnar material (not shown) is pressure-molded by driving into the die 12 and a bottomed hole A1 is formed on the bottom by a molding pin 11 as shown in FIG. Form.

Next, as shown in FIG. 7, at the final stamping station S2 provided with the die 15 having the forming pin 14 at the center and the upper surface forming punch 16, the columnar punch 16 is driven into the die 15 to be intermediate. A molded product A is forged and molded, and has a bottomed tubular shaft portion 2 as shown in FIG. 7 and a head portion 3 integrally provided at one end of the shaft portion 2 and having a hexagonal outer circumference. The final molded product B is formed.

In that case, when the upper surface forming punch 16 is driven, a small hexagon that matches the contour shape of the circular shaft-shaped central shaft portion 31 on the upper surface of the head 3 and the remaining head portion 3 excluding the central shaft portion 31 portion. A driving recess 32 having a shape is formed. By driving to form the driving recess 32 having a hexagonal shape, the annular flat seat surface 33 having a geometrical tolerance flatness to prevent oil bleeding is simultaneously formed on the bottom surface of the head 3. It is formed with high precision.

Here, the driving recessed portion 32 is formed from the outer periphery of the central shaft portion 31 to near the outer periphery of the head portion 3, and the central shaft portion side of the driving recessed portion 32 becomes deeper and gradually reaches the outer peripheral side of the head portion 3. It is formed in a tapered shape so as to be shallow. By forming the tapered shape that gradually becomes shallower toward the outer peripheral side in this way, when the hexagonal driven recess portion 32 is formed on the upper surface of the hexagonal head 3, the wall thickness around the central shaft portion 31 is formed. The portion can be effectively released to the outer peripheral side, and the square edge portions 34 ... 34 around the hexagonal outer circumference of the head 3 can be plastically deformed smoothly and reasonably so as to rise upward, and can be forged with high accuracy. As a result, in order to prevent oil from seeping into the bottom surface of the head 3, that is, the annular flat seat surface 33 due to the driving process of the hexagonal driving recess 32 on the upper surface of the hexagonal head 3. The geometrical tolerance flatness can be improved.

After that, in the final molded product C, a screw 21 is formed on the outer periphery of the shaft portion 2 by rolling or cutting in a post-process, whereby the plug 1 as a product shown in FIGS. 1 to 5 is formed.

Next, the operation of the closing plug according to the present invention configured as described above will be described.

According to the plug according to the present invention, the central shaft portion 31 on the upper surface of the hexagonal head 3 and the central shaft portion 31 portion are removed to resemble the hexagonal shape of the outer periphery of the head as described above. A small hexagonal driven recess 32 is formed, and an annular flat flat seat surface 33 having a geometrical tolerance flatness for preventing oil bleeding is formed on the bottom surface of the head 3. Therefore, it is possible to reliably prevent oil bleeding on the annular flat seat surface formed on the bottom surface of the head, while eliminating the need for special cutting as in the conventional case. In addition, mass production by a multi-stage pressure forming machine is easy and easy, and can be manufactured at low cost.

Further, the central shaft portion 31 on the upper surface of the head portion 3 is formed in a circular shaft shape, the driving recess portion 32 is formed from the outer periphery of the central shaft portion 31 to the vicinity of the outer circumference of the head 3, and the driving recess portion is formed. Since the central shaft portion 31 side of the 31 is formed in a tapered shape so as to be deeper and gradually becomes shallower toward the outer peripheral side of the head portion 3, the driving recess portion 32 having a hexagonal shape is formed on the upper surface of the head portion 3 having a hexagonal shape. Is formed by driving, the thick portion around the central shaft portion 31 is effectively released to the outer peripheral side, and the square edge portions 34 ... 34 around the hexagonal outer circumference of the head 3 are reasonably smooth so as to rise upward. It can be plastically deformed to be forged with high precision. As a result, the geometrical tolerance flatness of the bottom surface portion of the head portion 3, that is, the annular flat seat surface 33 can be remarkably improved by the hexagonal driving process, and oil bleeding can be reliably prevented.

In the above-described embodiment, the shape of the head 3 of the plug 1 has a hexagonal shape, but the shape is not limited to the hexagonal shape, and is not limited to the hexagonal shape, for example, a square shape, a pentagonal shape, or an octagonal shape. It may have a polygonal shape such as. In addition, although the drain plug provided in the oil tank has been described, it is not limited to the drain tank plug, and is used for various purposes such as an oil pan plug and a cooling water replacement plug. Of course, it can be widely used for closing plugs.

Further, according to the plug 1 of the present invention, the annular flat washer surface 33 itself formed on the bottom surface of the head 3 can sufficiently exert a function of directly preventing oil bleeding, but in use. Of course, a thin flat washer made of copper or aluminum may be sandwiched between the oil tank and the closing plug.

1 Closing plug 2 Shaft 21 Screw 3 Head 31 Central shaft 32 Driving recess 33 Circular flat seat surface

Claims (2)

A shaft portion having a screw on the outer circumference and a head portion integrally provided at one end of the shaft portion having a polygonal shape are provided, while the central shaft portion and the central shaft portion are excluded from the upper surface of the head portion. The remaining part is formed with a driving recess having a small polygonal shape that matches the contour shape of the outer circumference of the head, and the bottom surface of the head has a geometrical tolerance to prevent oil bleeding. A closing plug characterized in that an annular flat seat surface having flatness is formed. The central shaft portion on the upper surface of the head is formed in a circular shaft shape, the driving recess portion is formed from the outer periphery of the central shaft portion to the vicinity of the outer periphery of the head, and the central axis of the driving recess portion is formed. The plug according to claim 1, wherein the plug is formed in a tapered shape so that the portion side is deep and becomes gradually shallower toward the outer peripheral side of the head.

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