JPH0366519A - Internal thread forming method in press-fit flange of drum can or the like and internal theread forming composite tap used therefor - Google Patents

Abstract

PURPOSE:To surely perform forming and to prevent the state where the content of a drum can is contaminated by chips by cutting the inner peripheral wall for tapping of a cylindrical workpiece such as a press-fit flange of a drum can or the like to form an internal thread, and then further performing finish forming by rolling. CONSTITUTION:When a pressing ram 26 is advanced by the operation of a pressing drum driving cylinder to press a flange raw material 3A to a composite tap 1 in such a manner as to be fitted and coated, first an internal thread by a thread cutting edge 4 is formed on the peripheral wall 32 for tapping of the wall thickness of the flange raw material 30A. After forming the internal thead by the cutting edge 4, the flange raw material 30A is continuously pressed by the pressing ram 26. Whereupon, the internal thread portion is pressed by a helical projecting portion 10 for thread rolling of a finish rolling portion 3 at this time to smooth the surface and form an internal thread. The pressing ram 26 is reciprocated by the operation of the driving cylinder to repeat internal thread forming operation for a press-fit flange raw material 30 supplied from a chute 25 of a feed portion 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for forming an internal thread in a press-fit flange of a drum can, and a composite tap for forming an internal thread used in the method.

Conventional technology Conventionally, in order to form the internal thread of a press-fit flange of a drum can, the inner circumferential wall for tapping of the steel press-fit flange material was
Female threads were formed by cutting with a lathe or drill press equipped with a screw tap, or by cutting with a lathe equipped with a cutting tool.

Problems to be Solved by the Invention However, the surface roughness of the female thread formed by any of the above methods is rough and not smooth, and chips (chips) may adhere to the surface. When a press-fit flange is attached to the cylindrical mouth of a drum, when the plug is opened or closed, chips adhering to the surface of the female thread may fall into the drum, or otherwise the surface of the female thread may Since the roughness is rough and not smooth, there is a problem in that chips are generated when the plug is opened and closed, and the contents of the drum are contaminated by these chips.

An object of the present invention is to solve the above-mentioned problems of the prior art, to be able to reliably form a female thread in a cylindrical workpiece such as a press-fit flange, so that the surface of the female thread is very smooth, and the plug In [1], there is no generation of chips at all, and it is possible to prevent the contents of the drum from being contaminated by the chips. An object of the present invention is to provide a method for forming a female thread in a press-fit flange of a drum, etc., and a composite tap for forming the female thread used in the method, which can supply products with female threads to the market at low cost.

Means for Solving the Problems In order to achieve the above-mentioned object, a method for forming an internal thread in a press-fit flange of a drum can, etc. according to the present invention provides a method for forming an internal thread for threading of a cylindrical workpiece such as a press-fit flange of a drum can. This is characterized in that it is cut from one end to form a female thread, and then further finished formed by rolling.

Further, in the female thread forming method according to the present invention, the inner circumferential wall for tapping of a cylindrical workpiece such as a press-fit flange of a drum can is first cut from one end using a thread cutting device equipped with a cutting tap to form a female thread. Thereafter, this is further passed through a thread finish rolling device equipped with a thread rolling tap for final forming by rolling.

Further, the composite tap for forming a female thread used in the method for forming a female thread according to the present invention is capable of thread cutting in which a female thread is formed by cutting the inner circumferential wall for tapping of a cylindrical workpiece such as a press-fit flange of a drum from one end thereof. It consists of a thread cutting part equipped with a blade, and a thread finishing rolling part which is integrally connected to the rear end of the thread cutting part and has a substantially spiral convex part for thread rolling.

Example Next, embodiments of the present invention will be described based on the drawings.

The drawings show a case in which the present invention is applied to forming a female thread in a press-fit flange of a drum can.

In FIGS. 1 to 7 showing the first embodiment of this invention,
In the female thread forming method according to the present invention, after cutting the internal peripheral wall for tapping (32) of a press-fit type flange (cylindrical workpiece) (30A) of a drum from one end thereof to form a female thread (40), This is further finished formed by rolling.

The entire internal thread forming apparatus for carrying out the method of this invention is shown in FIG. This female thread forming device mainly includes a female thread forming section (15) equipped with a compound tap (1>), a feed section (16) that supplies a press-fit flange material (30A) to the female thread forming section (15), and a formed flange (30). It is composed of a flange holding part (17) that holds the flange and sequentially sends it forward, and a rotary shaft drive part/formed flange discharge part (18).

For details of the composite tap for female thread forming (1), see Figures 2 to 5.
As shown in the figure.

In the same figure, the composite tap (1) for forming a female thread is located inside the tapping circumference FI4 of the press-fit type flange (30^) of the drum can.
Cut the wall (82) from one end of the wall (82) to create a female thread (40〉).
Thread cutting part (2) that has been repaired with thread cutting blade (4) that forms
and a thread finish rolling part (3) integrally connected to the rear end thereof and having a substantially spiral convex part (10) for thread rolling.

The outer peripheral surface of the thread cutting part (2) of the compound tap (1) has a convex part (5) in which thread cutting blades (4) are lined up at predetermined intervals.
and chip relief recesses (6) are provided alternately so as to have a predetermined twist angle. Thread cutting part (2)
A through hole (7) is bored inside the bolt, and a recess (8) for fitting a bolt head is provided at the tip thereof.

There are also key grooves (9) on both sides of the other end of the threaded part (2).
is provided.

On the other hand, on the outer circumferential surface of the thread finish rolling part (3) of the compound tap (1>), grooves (11>) extending in the length direction of the thread finish rolling part (3) are arranged at predetermined intervals in the circumferential direction. The generally spiral convex portion (10) for thread rolling is a so-called fly screw.

This minimizes frictional resistance during rolling,
This is to prevent heat generation. Thread finish rolling part (3
) is provided with a through hole (12), and a key 03 that fits into the keyway (9>) of the threaded part (2) is provided on both sides of the tip, and Keyways (14) are provided on both sides.

In the female thread forming part (15), the compound tap (1
) is attached by fitting over the small diameter mounting part (21) at the tip of the rotating shaft (20), and the thread finishing rolling part ( The key (13) of 3) is fitted, and the key (22) provided on the step near the tip of the rotating shaft (20) is fitted into the keyway (14) of the thread finish rolling part (3). The screw hole (23) provided in the small diameter attachment part (21) of the rotating shaft (20) is located from the recess (8) for fitting the bolt head at the tip of the thread cutting part (2) of the compound tap (1). ni bolt (24
> is screwed in and tightened, the thread cutting part (2) and thread finish rolling part (3) of the compound tap (1) are screwed in and tightened.
is firmly fixed to the small diameter attachment part (21) at the tip of the rotating shaft (20) (see Figures 82 and 4).

In addition, the feed portion (16) has a press-fit type flange material (
30A) from above, a pressing ram (2B) horizontally arranged below this, and a drive cylinder (as shown) for the pressing ram (2B). There is a flange material (30) at the tip of the pressing ram (26).
A notch (27) into which A) fits is provided.

Here, as shown in FIG. 2, the press-fit flange material (30^) has a substantially cylindrical shape, and a collar (31) having an octagonal outer peripheral edge when viewed from above is provided at the lower end thereof, and the lower part An inner circumferential wall (32) for tapping a screw within the thickness is provided, and an inclined surface portion (33) for contacting the packing is provided inside between the inner circumferential wall (32) for tapping the screw within the thickness and the thin upper portion. It is being The notch (27) at the tip of the pressing ram (2B) is
It opens upward, and the both side walls and bottom wall portion of the notch (27>) are shaped to follow the octagonal outer periphery of the collar (31>), and the notch (27>) has a flange material (30A). Tsuba (Tsuba)
31) is fitted.

Further, the flange holding part (17) is provided with a holding body (28) for horizontally holding the rotating shaft (20> on which a large number of molded flanges <30> are fitted). The holding body (28) has a pre-formed flange (30).
A flanged rotating shaft insertion hole (29) with a circular cross section with an eye slightly larger than the octagonal outer edge of the tsuba (31) is provided,
Inside this insertion hole (29) are a number of pre-formed flanges (
The rotating shaft (20), on which the screws 30) are continuously fitted, is inserted, and the rotating shaft (20>) is held by these molded flanges (30>) so that it can rotate freely.

The formed flange (30) is sequentially extruded forward as the flange material (30A) is formed into a female thread by the operation of the pressing ram (26).

The rotating shaft drive unit and formed flange discharge unit (18) is a rotating shaft (20) that holds a formed flange (30).
An L-shaped bar (34) having a horizontal part (34a) attached to the central part of the front end and a hanging part (34b) continuous to the tip of the bar (34);
3B> and a pulley (35) attached to the side surface of the lever rotation member (35) on the holding body 28> side and around which a belt (38) is wound. 37), a pulley (37) and a lever rotation member integrated therewith (
35> (as shown).

During rotation, the tip of the hanging portion (34b) of the L-shaped bar (34) fits inside the right end of the formed flange discharge opening (36) of the substantially circular lever rotation member (35>). A notch (39) for insertion is provided.

Function In the above female thread forming device, the thread cutting part (2) and the thread finishing rolling part (3) of the compound tap (1) are connected to the small diameter mounting part ( 2
1) is firmly fixed. When the motor of the rotary shaft drive unit (path shown) is operated in this state, the belt <3
8) and a pulley (37), a substantially circular lever rotation member (35) is rotated, and the L-shaped bar (3
4) The tip of the hanging part (34b) is the discharge opening (3B>
The L-shaped bar (34) is fitted into the notch (39) at the side end and is rotated together with the lever rotation member (35).

On the other hand, the press-fit flange material (30A) is supplied from above by the hanging chute (25) of the feed section (lB), and is fitted into the notch (27) at the tip of the press ram (26), and in this state, When the press ram (2B) moves forward by the operation of the press ram drive sill (path shown) and presses the flange material (30A) overlying the compound tap (t), first the thick wall of the flange material (30A) is pressed. A female thread (4
o> is formed. In this case, the completion rate of the female thread (40) is 80 to 90%. After the cutting blade (4) forms the female thread (4o), when the pressing ram (26) continues to press the flange material (30A), this female thread (40) part becomes the thread finishing rolled part ( 3)
Pressed by the thread rolling spiral convex part (10) of
The surface is smooth and a perfect female thread (4o) can be formed with a completion rate of 80 to 90%. Thereafter, the press ram (26) is reciprocated by the operation of the drive cylinder, and the chute (25) of the feed section (16>)
The above-mentioned operation of forming the female thread (4o) on the press-fit flange material (30A) supplied by the above-described method is repeated.

In this way, the rotating shaft (20〉) has many pre-formed flanges (
30> are successively fitted and covered in order. The rotating shaft (20) having these molded flanges (30) is inserted into the octagonal flanged rotating shaft insertion hole (29) of the holder (28).
) and held horizontally, as a result,
The rotating shaft (20) is held for free rotation by a molded flange (30). The formed flange (30) is sequentially extruded forward as the flange material (30A) is formed into a female thread by the operation of the suppression ram (26).

One of the molded flanges (30) is attached to the rotating shaft (2
When reaching the front end of 0), 1 due to the operation of the pressing ram (2G)
When thread forming is completed, the flange material (30A) falls from the front end of the rotating shaft (20>) by being pushed by the suppression ram (26).
〉The tip of the hanging portion (34b) of the L-shaped bar (34) at the front end is fitted into the notch (39〉).
(See Figure 6 and the dashed-dotted line in Figure 7), rotation axis (
20) can rotate freely only by being held by a large number of molded flanges (30>), so when the opening (36>) of the substantially circular lever rotation member (35) faces downward (7th (see figure), fallen formed flange (3
0) pushes away the hanging part (84b) of the L-shaped bar (34) so as to come out of the notch (39) by its weight, and as a result, the hanging part (34b) of the L-shaped bar (34>)
is facing downward, and the formed flange (3o) passes through this hanging part (34b) and naturally falls onto the discharge conveyor (path shown) arranged below, and is automatically It is something that is discharged.

As shown in Figures 10 and 11, the top E (
41) is provided with a rising cylinder part (42) for fixing the flange.
) is provided in an upwardly projecting shape, and an annular step portion (43) is provided at the center of the height of this rising cylinder portion (42).

The flange (
30> is press-fitted into this rising cylinder part (42) from below,
Its upper edge (30a) is bent outward and wound around the upper edge (42a) of the rising tube part (42). The flange (30) has an octagonal outer circumferential edge at the lower edge.
31〉, the same-shaped anti-rotation hem below the stepped portion (43) (
42b). Note that a fixed gasket (44) is filled between the annular step portion (43) of the rising cylinder portion (42) and the collar portion (31) of the flange (30>).

8 and 9 show a second embodiment of the invention.

In the figure, the method according to the present invention is performed on the inner circumference r for tapping of the press-fit type flange (30A) of the drum can! ! (32)
is first cut from one end using a thread cutting device equipped with a cutting tap (2 people) to form a female thread (40〉), and then this is further passed through a thread finish rolling device equipped with a thread rolling tap (3A). Finish forming is performed by rolling.

Here, the thread cutting device converts the composite tap (1) in the female thread forming device shown in FIG. 1 into a cutting tap (2A).
The rolling device has the same configuration as the beam by simply replacing the compound tap (1) with the rolling screw tap (8A). Therefore, the same reference numerals are given to the same parts in the drawings.

Note that the cutting tap (for two people) of the thread cutting device has a protrusion (5) in which the thread cutting blades (4) are lined up at predetermined intervals on its outer circumferential surface, and a recess for chip release (6) in a predetermined manner. The same point as in the case of the thread cutting part (2) of the compound tap (1) is that they are provided alternately so as to have a twist angle of
It is longer than the thread cutting part (2) of the compound tap (1).It is also longer than the thread cutting part (2) of the compound tap (1).
) is different from the compound tap (1) in that it has a substantially spiral convex portion (10) for thread rolling in the circumferential direction and a groove (11) extending in the length direction on its outer peripheral surface. Thread finish rolled part (
Although it is the same as in case 3), it is made considerably longer than the thread finish rolling part (3) of the composite tap (1).

Although not shown in the figure, a female thread (
In order to supply the press-fit flange (30A) after forming 40) to a thread rolling device for the next finishing forming,
This may be done manually by an operator, or may be done automatically by placing an appropriate conveyor between the two devices.

The method of the present invention and the composite tap for forming female threads used in the method are applicable not only to press-fit flanges of drums, but also to all other types of workpieces in which female threads are formed by cutting the inner peripheral wall for tapping of cylindrical workpieces. It is applicable in the case.

Effects of the Invention As described above, the method for forming a female thread in a press-fit flange of a drum can, etc. according to the present invention involves cutting the inner circumferential wall for tapping of a cylindrical workpiece such as a press-fit flange of a drum can from one end thereof. After the female thread is formed, this is further finished formed by rolling, so the female thread can be reliably formed in a cylindrical workpiece such as a press-fit flange, and the resulting press-fit flange, etc. The surface of the internal thread is very smooth, and there is no generation of chips when the plug is opened or closed, which can prevent the contents of the drum from being contaminated by chips. This effect is achieved.

Further, the composite tap for forming an internal thread used in the method of forming an internal thread in a press-fit flange of a drum can, etc. of the present invention is as follows:
As mentioned above, there is a thread cutting part equipped with a thread cutting blade that cuts the inner circumferential wall for tapping a cylindrical workpiece such as a press-fit flange of a drum from one end to form a female thread, and Since it consists of a thread finish rolling part that is integrally connected to the end and has a spiral convex part for thread rolling, it is possible to form an internal thread on a cylindrical workpiece such as a press-fit flange in one step.
It is extremely simple and reliable, and therefore equipment and operating costs are extremely low, and it is suitable for mass production, which greatly reduces the manufacturing cost of press-fit flanges, etc., and improves quality. This has the effect of supplying excellent female threaded products such as press-fit flanges to the market at low cost.

[Brief explanation of drawings]

1 to 7 show a first embodiment of this invention,
Fig. 1 is a longitudinal sectional view of the entire apparatus for implementing the method of the present invention, Fig. 2 is an enlarged partially cutaway perspective view of the main part showing the composite tap portion of Fig. 1, and Fig. 3 is an enlarged sectional view of the composite tap. , Fig. 4 is a sectional view taken along line ■-■ in Fig. 3, Fig. 5 is a sectional view taken along line V-v in Fig. 3, and Fig. 6 is a sectional view taken along line Vl-Vl in Fig. 1. , shows a state where a female thread is being formed in the press-fit flange material. FIG. 7 is a view taken along the same arrow, showing a state in which the female thread-formed flange is dropped. Figure 8 and W
9 shows a second embodiment of the present invention, FIG. 8 is a longitudinal sectional view of the entire thread cutting device in the method of the invention, and FIG. 9 is a longitudinal sectional view of the entire thread finishing and rolling device in the method of the invention. FIG. FIG. 10 is an enlarged cross-sectional view of main parts showing the state before the flange thread-formed by the method of the present invention is attached to the upright cylindrical part of the top plate of a drum;
The figure is an enlarged sectional view of the main part showing the state after the same is installed. (1>...Composite tap for female thread forming, (2)...Thread cutting part, (8>...Thread finishing rolling part, (2^>・
... Cutting tap, (3A) ... Thread finishing and rolling tap, (4) ... Thread cutting blade, (5) ... Spiral convex part for thread rolling, (10) ... Thread rolling A roughly spiral convex part, (
15)...Female thread forming part, (16)...Feed part, (17)...Flange holding part, (18)...Rotary shaft drive part and formed flange discharge part, (20>...・Rotating shaft, (21)...small diameter mounting part, (26>...pressing ram, (27)...notch, (28>...holding body)
(29)...Rotary shaft push-through hole with flange, (SO)
...Pre-formed flange, (30a)...Top edge, (3
0A)...Press-fit flange material (cylindrical workpiece),
(32)...Inner circumferential wall for tapping screws, (34)...L-shaped bar (35)...Lever rotation member, (36>...
...Molded flange discharge opening, (39>...notch, (40>...female thread, (41)...top plate, (
42)...Rising cylinder part. that's all

Claims (1)

[Claims] (1) Cylindrical workpieces such as press-fit flanges of drums (3
A press-fit type flange for a drum can, etc., characterized in that the inner circumferential wall for tapping (32) of 0A) is cut from one end to form a female thread (40), and then this is further finished formed by rolling. female thread forming method. (2) The inner circumferential wall (32) for tapping of a cylindrical workpiece (30A) such as a press-fit flange of a drum can is first cut from one end using a thread cutting device equipped with a cutting tap (2A) to create a female thread. The press-fit type flange of a drum can, etc. according to claim 1, characterized in that after forming (40), this is further subjected to a thread finish rolling device equipped with a thread rolling tap (3A) for finishing forming by rolling. female thread forming method. (3) Cylindrical workpieces such as press-fit flanges of drums (3
A thread cutting part (2) equipped with a thread cutting blade (4) for cutting the internal peripheral wall (32) for tapping a screw from one end thereof to form a female thread (40); A composite tap for forming an internal thread, which is used in a method for forming an internal thread in a press-fit flange of a drum can, etc., comprising a thread finishing rolling part (3) connected to the thread rolling part and having a substantially spiral convex part (10) for thread rolling.