JP2002137035A - Method of form rolling with variable lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of form rolling which can apply form rolling on an outer circumference of a hollow tube and also change lead angle and/or depth of thread in process. SOLUTION: When applying form rolling on the outer circumference of the hollow material 13 using a round die 12a with a single rolling tooth 3, movement of the hollow material 13 in its axial direction is kept free, while the material 13 moves reciprocally by rotating the die 12a in normal and reverse directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable lead rolling method for manufacturing a feed screw, a worm gear or the like by rolling using a rolling round die.

[0002]

2. Description of the Related Art In general, a rolled round die used for rolling a screw has a plurality of thread shapes formed on an outer peripheral surface of the die, and is used for a work held by a center base or the like. The work is plastically worked by rotating and approaching and pushing a screw thread into the outer peripheral surface of the work to form a spiral screw on the outer peripheral surface of the work.

[0003]

However, in a rolled round die having a plurality of thread forms as described above, the rolling pressure increases when the rolled round die is pressed into the outer peripheral surface of the work. Even when trying to roll a deep groove shaped screw, there is a problem that the hollow pipe is crushed by the rolling pressure.

Further, in the above-described rolled round dies, since a plurality of thread forms have the same lead, the lead angle of the screw formed on the outer peripheral surface of the work and the depth of the thread groove are changed on the way. Could not be processed.

Accordingly, an object of the present invention is to provide a variable lead rolling method that enables thread rolling on the outer peripheral surface of a hollow pipe and allows the lead angle of a screw and the depth of a thread groove to be changed on the way. To provide.

[0006]

SUMMARY OF THE INVENTION The inventor of the present invention uses a rolled round die having a single thread shape to suppress the rolling pressure applied to a work and to rotate the rolled circular die forward and backward. Is repeated to form a thread groove having a predetermined depth. More specifically, the variable lead rolling method according to claim 1 is free from movement in the axial direction of the work when machining a screw on the outer peripheral surface of the work using a rolling tool having a single thread shape. And the work is reciprocated by rotating the rolling tool forward and reverse.

According to the present invention, since a single thread is formed on the rolling tool, the pressure for pushing the work is small, and the hollow pipe is not crushed. Further, when the work is reciprocated and the rolling is repeated, the forward / reverse rotation of the rolling tool is controlled with high precision, thereby preventing the displacement of the thread groove and forming a deep groove screw.

According to a second aspect of the present invention, there is provided a variable lead rolling method, wherein a thread is formed on an outer peripheral surface of a work by using a rolling tool having a single thread form. The lead angle of the screw is controlled by tilting.

According to the present invention, by changing the axis inclination of the rolling tool during the rolling process, it is possible to form a screw having an irregular lead angle on the outer peripheral surface of the work.

In the variable lead rolling method according to the third aspect, when a screw is formed on an outer peripheral surface of a work using a single rolled tool having a thread form, an axial distance between the rolled tools is reduced. The depth of the thread groove is controlled by changing the depth of the thread groove.

According to the present invention, by changing the inter-axis distance of the rolling tool during rolling, it is possible to form a screw in which the depth of the thread groove is not constant on the outer peripheral surface of the work.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rolling method according to the present invention will be described below in detail with reference to the accompanying drawings. 1 to 6 show an embodiment of the present invention. Among them, FIG. 1 is a conceptual diagram of a rolling device for carrying out the variable lead rolling method of the present invention, and FIGS. 2 and 3 are enlarged views showing a thread shape of a rolling round die used in the present invention. is there. Also,
FIG. 4 is a sectional view taken along the line AA of FIG.
Is a front view of a workpiece clamping mechanism, and FIG. 6 is a plan view showing a part of the clamping mechanism.

First, a round-die rolling device for carrying out the rolling method of the present invention will be described with reference to FIGS. This round die type rolling device 11 includes a rolled round die 12a having a single screw thread formed on both sides of a hollow material 13 used as a work, and a plain die 1 having a smooth outer peripheral surface.
2b, the spindles 14a and 14b of the dies approach each other while rotating, and the rolled round die 12a and the plain die 1
2b, the hollow member 13 is interposed therebetween, and a screw is rolled on the outer peripheral surface thereof. A pair of spindles 14a, 14b
Are rotatably supported by the die holders 15a and 15b so as to be parallel to each other. One die holder 15a is
The first die moving table 16a is provided on the inner surface of the first die moving table 16a, and the other die holder 15b is provided on the opposite inner surface of the second die moving table 16b. In particular, these die holders 15a, 15b are provided so that the spindles 14a, 14b can be tilted in a plane (vertical plane) orthogonal to the direction of movement of the dice movers 16a, 16b.
6b so as to be rotatable. Main shafts 14a, 14b
Are set such that the rolling position of the hollow member 13 is located on a line S connecting the two.

The single thread form formed on the outer peripheral surface of the rolled round die 12a is either a case where only the forming teeth 3 are formed as shown in FIG. 2 or a case where the forming teeth 3 are formed as shown in FIG. There are cases where biting teeth 4 and 5 are provided on both sides of the tooth 3. The bite teeth 4 and 5 are not limited to one mountain, but are equal leads in this case. The rolled round die 12a shown in FIG. 2 is useful when the lead angle is changed or the depth of the thread groove is changed during rolling, and the rolled round die shown in FIG. 12a is useful when it is not necessary to change the lead angle or the depth of the thread groove because the thread processing is facilitated by the bite teeth 4 and 5.
By using the plain die 12b, the contact length with the hollow material 13 is increased and the transmission torque from the rolled round die 12a is correspondingly increased. However, instead of the plain die 12b, the same rolled round die as described above is used. Dice 12a can also be used. The number of the rolled round dies 12a and the plane dies 12b is not limited to two.

The inclination conversion of the die holders 15a and 15b is executed by the spindle inclination mechanisms 17a and 17b. The main shaft tilting mechanisms 17a and 17b are composed of a tilt conversion gear provided on each of the die holders 15a and 15b, and a pinion gear meshing with the tilt conversion gear, and a shaft tilting servomotor 18 having a pinion gear attached to a tip thereof.
Reference numerals a and 18b are disposed on the side surfaces of the die moving tables 16a and 16b.

In controlling the tilt conversion of the die holder 15a, as shown in FIG. 4, the pinion gear is first rotated by driving the shaft tilt servo motor 18a, and the shaft is tilted to the die holder 15a via the tilt conversion gear. The torque is transmitted. As a result, the die holder 15a is pivoted about the tilt center 19a as a fulcrum.
Rotate by the amount corresponding to the rotation of. Therefore, the main shaft 14a, which maintains the parallelism, can be inclined + α ° (indicated by a two-dot chain line in the figure) upward and −α ° (indicated by a two-dot chain line in the figure) downward in the vertical plane. Specifically, encoders (not shown) for measuring the inclination angles for detecting the inclination angles of the spindles 14a and 14b are attached to the ends of the spindles 14a and 14b, and the inclination angles measured by the encoders are fed back. Thus, the rotation angles of the spindle inclination servomotors 18a and 18b are numerically controlled. Thereby, the tilt angle can be controlled with high accuracy. The other die holder 1
Similar control is performed for 5b.

As described above, by inclining the main shafts 14a and 14b with high precision, the hollow member 13 can be made to walk at a constant speed, and the rolled round die 12a is formed.
And the hollow material 13 while rotating the plane die 12b.
, The hollow member 13 is given a propulsive force in the axial direction. Further, since the rotation speeds and the forward and reverse rotation directions of the main shafts 14a, 14b are controlled by the servo motors 21a, 21b, the hollow member 13 for repetitive rolling can be reciprocated in the axial direction, and the outer peripheral surface is formed. Thus, a thread groove having a predetermined depth can be machined.

The mechanism for moving the rolled round dies 12a and the plane dies 12b is performed by a die moving table moving mechanism 24, as shown in FIG. The die moving table moving mechanism 24 is provided with the above-described die holders 15a and 15b.
The first die moving table 16a and the second die moving table 16b provided on the inner surface, respectively, and the second die moving table 1
6b. These die moving tables 16a, 16b and pressure plate 2
As shown in FIG. 4, each of the reference numerals 6 is attached to a pair of slide rails 28a and 28b fixed on the base 27 so as to be slidable in the left-right direction. Further, between the first die moving table 16a and the pressure plate 26, four beam shafts 2 having the same cross-sectional shape are provided at the four corners of the inner surfaces facing each other.
9, the both ends of the beam shaft 29 are fixed to the first die moving table 16a and the pressure plate 26, respectively.
Therefore, the first die moving table 16a and the pressure plate 2
6 slides integrally on the slide rails 28a and 28b without changing the relative position.

The second die moving table 16b is slidably mounted on the slide rails 28a and 28b between the first die moving table 16a and the pressure plate 26, and allows the four beam shafts 29 to pass therethrough. Through holes are provided at the four corners of the side surface. A pushing mechanism 30 such as a hydraulic cylinder is fixed to the pressure plate 26. The pushing mechanism 30 includes a cylinder shaft 31 that expands and contracts in the same direction as the die moving table 16b, and the tip of the cylinder shaft 31 is fixed to the outer surface of the second die moving table 16b.

A pair of racks and pinions are provided between the second die moving table 16b and the pressure plate 26 (not shown). The pinion is fixed to the upper surface of the base 27. One rack is fixed to the lower end of the pressure plate 26, and the other rack is fixed to the lower end of the second die moving base 16b, and each is engaged with the pinion.

When the pushing mechanism 30 is operated, the cylinder shaft 31
When the second die moving table 16b is pushed, the second die moving table 16b is pushed toward the hollow member 13 and slides on the slide rails 28a and 28b as shown in FIG.
Slide to the left of. On the other hand, since a rack and pinion is provided between the second die moving table 16b and the pressure plate 26, the pressure plate 26 slides in a direction opposite to the moving direction of the second die moving table 16b. . The moving distance is the same as that of the second die moving table 16b. At this time, the first die moving table 16a connected to the pressure plate 26 by the four beam shafts 29 also moves by the same distance toward the hollow member 13 in the same direction as the pressure plate 26, that is, rightward in FIG. I do. Therefore, the first die moving table 16a and the second die moving table 16b slide toward each other toward the hollow member 13 by the same distance and approach each other.

FIGS. 5 and 6 show a clamping mechanism of the hollow member 13. FIG. The hollow member 13 is a stop center 35.
And between the tailing center 36 in the axial direction. The stop center 35 is fixed to one center base 37a, and the centering center 36 is slidably mounted on the other center base 37b. A pneumatic or hydraulic cylinder 38 is fixed to the center table 37b, and the centering center 36 moves in the axial direction (X direction in the figure) of the hollow member 13 by the operation of the cylinder 38. In addition, a span adjusting rack 39 for adjusting the span and a pinion 40 are provided below the center stands 37a and 37b. Center stand 37a, 37b
Is slidably mounted on a center base slide rail 41 provided in the axial direction of the hollow member 13,
The movement in the axial direction 3 is free.

Next, a rolling method of the present invention using the above-mentioned round die rolling device will be described. First, after the hollow member 13 is clamped in the axial direction, the rolled round dies 12a and the plane dies 12b are set to a predetermined inclination angle by using the shaft inclination mechanisms 17a and 17b, and the lead angle of the screw is determined. Next, the hollow material 1 is rotated while operating the pushing mechanism 30 to rotate the rolled round die 12a and the plain die 12b with each other.
3 and rolled round die 12a and plain die 1
2b is sandwiched between the hollow member 13. Rolled round die 12
a and the plane die 12b are inclined,
By the pressing of the rolled round die 12a and the plain die 12b, the hollow material 13 starts to walk by receiving the propulsion force in the axial direction, and a spiral screw groove is formed on the outer peripheral surface thereof. The step distance of the hollow member 13 is determined by the rotation amount of the rolled round die 12a and the plane die 12b. When the rolled round die 12a and the plain die 12b rotate by a predetermined amount, the servo motors 21a and 21b rotate in the reverse direction, and the hollow member 13 moves by a predetermined amount in the reverse direction.
Each time, the main shafts 14a and 14b of the dies gradually approach the hollow material 13, and the thread groove can be formed gradually deeper by the amount of pushing from the rolled round die 12a.

FIG. 7 shows conditions for forming a screw groove having the same lead angle on the outer surface of the hollow member 13. Here, in the drawing, the solid line represents the number of revolutions and the direction of rotation of the rolled round die 12a, and the hollow material 13 is rotated twice in the normal direction and once in the reverse direction to make the hollow material 13 reciprocate one and a half times. I have. In the figure, the dashed line indicates the main shaft 14a of the rolled circular die 12a.
The position of the main shaft 14a approaches the hollow material 13 every time the rotation direction of the rolled round die 12a changes, and the cut amount of the thread groove increases. The dotted line indicates the inclination angle of the rolled round die 12a, and the inclination angle θ (5 °) in FIG. 5 is constant during the rolling. FIG. 8 shows the hollow member 1.
The thread groove 6 is machined on the outer peripheral surface of the roller 3 under the above-described rolling condition, and the cut amount of the thread groove and the lead are constant.

FIG. 9 shows conditions for forming a thread groove having an irregular lead angle on the outer surface of the hollow member 13. In the drawing, the solid line represents the number of rotations and the direction of rotation of the rolled round die 12a, and the hollow member 13 is rotated once in the normal rotation direction and in the reverse rotation direction so that the hollow material 13 walks one round trip. In the figure, the dashed line indicates the position of the main shaft 14a of the rolled round die 12a, and approaches the hollow material 13 when the rotation direction of the rolled round die 12a changes from normal rotation to reverse rotation. The dotted line indicates the inclination angle θ of the rolled round die 12a,
3 gradually increases from both ends toward the center (3 ° → 5 ° → 3 °). The same applies to the reverse rotation of the rolled round die 12a. FIG. 10 is a view in which the thread groove 7 is machined on the outer peripheral surface of the hollow material 13 under the above-described rolling conditions. The cut amount of the thread groove 7 is constant, but the lead angle is the largest at the center of the hollow material 13. , Gradually decreasing toward both ends.

FIG. 11 shows conditions for forming a thread groove in which both the cut amount and the lead angle are not constant on the outer surface of the hollow member 13. In the drawing, the solid line represents the number of rotations and the direction of rotation of the rolled round die 12a, and the hollow member 13 is rotated once in the normal rotation direction and in the reverse rotation direction so that the hollow material 13 walks one round trip. In the figure, the dashed line indicates the rolled round die 12a.
In the same manner as described above, when the rotation direction of the rolled round die 12a shifts from normal rotation to reverse rotation, the rotation direction of the rolled die 12a approaches the hollow material 13 and the spindle 14a also moves in the middle of cutting.
a is moved closer to or farther away from the hollow member 13 to control its position. In this embodiment, the central portion is closer to the main shaft 14a than both ends of the hollow member 13, and as a result, the depth of the thread groove is deeper in the central portion. The dotted line indicates the inclination angle θ of the rolled round die 12a, and conversely, the center portion of the hollow material changes from 5 ° to 3 ° to 5 ° from both ends. The same applies to the reverse rotation of the rolled round die 12a.
FIG. 12 shows the threaded groove 8 machined on the outer peripheral surface of the hollow material 13 under the above-described rolling conditions. The cut amount of the threaded groove 8 is the deepest at the center of the hollow material and gradually decreases toward both ends. Also, the lead angle is also the smallest at the center of the hollow material,
It gradually becomes larger toward both ends. Thus, by controlling the distance between the spindles 14a and 14b between the rolled round die 12a and the plane die 12b, the thread groove depth of the feed screw can be easily controlled.

[0027]

As described above, according to the variable lead rolling method according to the present invention, when a thread is machined on the outer peripheral surface of a work using a rolling tool having a single thread form.
By controlling the forward / reverse rotation of the rolling tool, thread rolling to a hollow material became possible.

According to the variable lead rolling method according to the present invention, the screw lead formed on the outer peripheral surface of the hollow material can be controlled by changing the inclination angle of the spindle of the rolling tool during rolling. it can. Also, by changing the distance between the spindles of the rolling tool during rolling, the depth of the thread groove formed on the outer peripheral surface of the hollow material can be controlled.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a round-die rolling device for carrying out a rolling method of the present invention.

FIG. 2 is an enlarged view showing a thread shape of a rolled round die used in the present invention.

FIG. 3 is an enlarged view showing another embodiment of the rolled round die used in the present invention.

FIG. 4 is a cross-sectional view taken along the line AA of FIG. 1 showing the main shaft tilting mechanism.

FIG. 5 is a side view showing a work clamping mechanism.

FIG. 6 is a plan view showing a part of the clamp mechanism shown in FIG. 5;

FIG. 7 is a graph showing rolling conditions when a thread groove having the same lead angle is formed on the outer surface of a work.

FIG. 8 is a work diagram in which a thread groove is machined according to the rolling condition.

FIG. 9 is a graph showing a rolling condition when a thread groove having an irregular lead angle is formed on the outer surface of a work.

FIG. 10 is a view of a work in which a thread groove is machined according to the rolling condition.

FIG. 11 is a graph showing rolling conditions when a thread groove in which both the cut amount and the lead angle are not constant is formed on the outer surface of the work.

FIG. 12 is a work diagram in which a thread groove is machined according to the rolling condition.

[Explanation of symbols]

 3 Molded tooth (single thread shape) 12a Round die (rolling tool) 13 Hollow material (work)

Claims (3)

[Claims] When a screw is formed on an outer peripheral surface of a work by using a rolling tool in which a single thread shape is formed, the work in the axial direction of the work is made free and the rolling tool is rotated forward and backward. A variable lead rolling method characterized by reciprocally moving a work. 2. When a screw is formed on the outer peripheral surface of a work using a rolling tool having a single thread shape, a lead angle of the screw is controlled by inclining the rolling tool with respect to the work. A variable lead rolling method, comprising: 3. When a screw is formed on an outer peripheral surface of a work using a rolling tool having a single thread form, the depth of a thread groove is controlled by changing a center distance between the rolling tools. A variable lead rolling method, characterized in that: