JP2016132001A - Rolling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling method by which elongation of a life of a movable round die having thread ridges on an outer peripheral surface can be achieved.SOLUTION: A rolling method in which a rolling apparatus, which comprises a pair of rotatable round dies having thread ridges 22 on an outer peripheral surface thereof and in which one of the pair of round dies is variable in a position for a work-piece, is used, the rotatable round die is pushed onto the work-piece while rotating by the rolling device, whereby rolling of the work-piece is performed. In the movable round die, a curvature radius of an apex 23X of a part 22X of the thread ridges is relatively larger than a curvature radius of an apex 23X of other parts 22Y of thread ridges, and the part 22X of the thread ridges of which the apex has a relatively larger curvature radius is firstly brought into contact with the work-piece 30.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rolling method.

Compared with machining by cutting and grinding, processing by rolling is (1) shorter processing time, (2) can save materials, (3) high product accuracy and beautiful finish, (4) uniformity of finished dimensions High (5) It has advantages such as improved mechanical properties such as tensile strength and surface hardness.
The rolling method is roughly classified into a method using a flat die (flat die type rolling method) and a method using a round die (round die type rolling method).
According to the round die type rolling method, the rolling process can be performed with higher accuracy than the flat die type rolling method, and it is used for the processing of products having threads such as bolts.

In the round die rolling method, a pair of rotatable substantially cylindrical forming tools called round dies are used. Usually, of a pair of round dies, one round die is a fixed round die whose position is fixed, and the other round die is a movable round die whose position relative to the fixed round die is variable.
The pair of round dies are rotated in the same direction while being sufficiently separated from each other, a work piece (work) having a substantially columnar shape or a substantially cylindrical shape is disposed on the outer peripheral surface of the fixed round die, and the movable round die is moved. This is pressed against the workpiece (workpiece) while rotating. By a series of these operations, the workpiece (work) is sandwiched between a pair of round dies, and the workpiece (work) is rolled.
There is also a method in which both of the pair of round dies are movable round dies.
For the conventional general round die rolling method, refer to the section “Prior Art” of Patent Document 1.

JP 2000-051983

  By using a pair of round dies having a thread on the outer peripheral surface, the thread can be rolled on a workpiece. In this case, in the movable round die, the largest load is applied to the part that first contacts the workpiece (work) (contact start part), and the thread in this part is more likely to chip than the thread in the other part. There is a tendency for the lifetime to be shortened.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rolling method capable of extending the life of a movable round die having a thread on the outer peripheral surface.

The rolling processing method of the present invention is
Using a rolling processing apparatus provided with a pair of rotatable round dies having a thread on an outer peripheral surface, wherein at least one of the pair of round dies is a movable round die whose position with respect to a workpiece is variable. A rolling process method for performing a rolling process on the workpiece by pressing the movable round die against an object while rotating the workpiece,
In the movable round die, the radius of curvature of the top of a part of the thread is relatively larger than the radius of curvature of the top of the other part of the thread,
A part of the thread having a relatively large radius of curvature at the top is first brought into contact with the workpiece.

  ADVANTAGE OF THE INVENTION According to this invention, the rolling processing method which can aim at the lifetime improvement of the movable round die which has a thread on an outer peripheral surface can be provided.

It is process drawing (schematic side view) of the rolling method of one embodiment concerning the present invention. It is process drawing (schematic side view) of the rolling method of one embodiment concerning the present invention. They are a partial enlarged view (upper figure) of a part of outer peripheral surface of a movable round die, and a partial enlarged view (lower figure) of the other part of the outer peripheral surface of a movable round die.

  The present invention includes a pair of rotatable round dies having a thread on the outer peripheral surface, and at least one of the pair of round dies is a movable round die whose position relative to a workpiece (workpiece) is variable. The present invention relates to a rolling method for performing a rolling process on a workpiece (work) by pressing the movable round die against the workpiece (work) while rotating the device.

A workpiece (workpiece) is a member in which the outer shape of the cross section of at least a part to be rolled is substantially circular. The workpiece (workpiece) is, for example, a member in which at least a part to be rolled is substantially columnar or cylindrical.
The material of the workpiece (workpiece) is not particularly limited, and examples thereof include metals such as low carbon steel, alloy steel, aluminum alloy, and copper alloy.

  With reference to the drawings, a rolling method according to an embodiment of the present invention will be described.

  1A and 1B are schematic side views showing each step of the rolling method of the present embodiment. 1A shows a state before the movable round die 20 is brought into contact with the workpiece (workpiece) 30, and FIG. 1B shows a state after the movable round die 20 is brought into contact with the workpiece (workpiece) 30. .

2 is a partially enlarged view (upper view) of a part 21X of the outer peripheral surface 21 of the movable round die 20, and a partially enlarged view (lower view) of the other portion 21Y of the outer peripheral surface 21 of the movable round die 20. 2 is an enlarged view of a contact portion with respect to the workpiece (workpiece) 30 when the movable round die 20 is in the state shown in FIG. 1B. The lower view of FIG. 2 is an enlarged view of a contact portion with the workpiece (workpiece) 30 when the movable round die 20 is in the state shown in FIG. 1A.
In the upper and lower views of FIG. 2A, the upper side in the drawing is the workpiece (workpiece) 30 side. Moreover, the illustration right-and-left direction in the upper figure and lower figure of FIG. 2A is the illustration depth direction of FIG. 1A and FIG. 1B.

  As shown in FIGS. 1A and 1B, the rolling processing apparatus 1 includes a pair of round dies 10 and 20. The pair of round dies 10 and 20 are rotatable substantially cylindrical forming tools. Rotating shaft members 51 and 52 are inserted into the hollow portions of the pair of round dies 10 and 20, respectively. The rolling processing apparatus 1 is provided with known rotational drive means such as a motor that rotationally drives the rotary shaft members 51 and 52 (not shown).

In the present embodiment, one of the pair of round dies 10 and 20 is a fixed round die whose position is fixed, and the other round die 20 is a movable round whose position relative to the fixed round die 10 is variable. Dice.
The rolling processing apparatus 1 is provided with known moving means for moving the movable round die 20 (not shown).

  Rotation driving of fixed round die 10 and movable round die 20 (rotation start and end timing, rotation speed, etc.) and movement of movable round die 20 (movement start and end timing, movement direction, and movement speed) Etc.) is controlled by a known control method.

  First, as shown in FIG. 1A, the pair of round dies 10 and 20 are rotated in the same direction in a sufficiently separated state (in the figure, the direction of rotation is indicated by an arrow (in the illustrated example, a counterclockwise direction). Rotation direction))), and the work piece (workpiece) 30 is disposed so as to contact the outer peripheral surface of the fixed round die 10. The workpiece (workpiece) 30 is disposed on a cradle (not shown) called a rest.

Next, as shown in FIG. 1B, while the movable round die 20 is rotated, it is moved in parallel to the fixed round die 10 side (left direction in the illustrated example), and this is pressed against the workpiece (workpiece) 30.
Through the above series of operations, the workpiece (work) 30 is sandwiched between the pair of round dies 10 and 20, and the workpiece (work) 30 is rolled.
As shown in the figure, the rotation direction of the workpiece (workpiece) 30 is opposite to the rotation direction of the pair of round dies 10 and 20.

The fixed round die 10 has a screw thread (screw-like convex portion) (not shown) on the outer peripheral surface 11.
The movable round die 20 has a screw thread (screw-like convex portion) 22 on its outer peripheral surface 21 (see FIG. 2).
In FIG. 1A and FIG. 1B, the screw threads of the fixed round die 10 and the movable round die 20 are formed in a spiral shape from the near side of the drawing to the depth of the drawing like the known round die.

As shown in FIGS. 1A, 1B, and 2, in the movable round die 20, a part 22X of a thread 22 formed on a part 21X of the outer peripheral surface 21 is a top part 23X having a relatively large curvature radius R. The other portion 22Y of the screw thread 22 formed on the other portion 21Y of the outer peripheral surface 21 has a top portion 23Y having a relatively small curvature radius R.
In FIG. 1A and FIG. 1B, a part 21X of the outer peripheral surface 21 is a region surrounded by a broken-line circle, and the other part 21Y of the outer peripheral surface 21 is a remaining region of the outer peripheral surface 21 (a region excluding a part 21X). .

As described above, the movable round die 20 is designed such that the curvature radius R of the top portion 23X of the part 22X of the thread 22 is relatively larger than the curvature radius R of the top part 23Y of the other portion 22Y of the thread 22.
If the curvature radius R of the top portion 23X of the part 22X of the thread 22 is R1, and the curvature radius R of the top portion 23Y of the other part 22Y of the thread 22 is R2, then R1> R2.
The thread of the movable round die 20 forms a thread valley in the workpiece (workpiece) 30. The radius of curvature R of the thread valley formed on the workpiece (workpiece) 30 is R3. The curvature radius R2 of the top portion 23Y of the other portion 22Y of the screw thread 22 is preferably matched with the curvature radius R3 of the thread valley formed on the workpiece (workpiece) 30.
That is, it is preferable that R1> R2 = R3.

In the present embodiment, as shown in FIGS. 1A and 1B, a portion 22X of a screw thread 22 having a relatively large curvature radius R at the top portion is first brought into contact with a workpiece (workpiece) 30 ( Contact start part).
Adopting known control such as NC (Numerical Control) control, the forward speed and the rotational speed of the movable round die 20 are controlled according to the position of the part 22X of the thread 22 having a relatively large curvature radius R at the top. By doing so, it is possible to control the part of the thread 22 having a relatively large curvature radius R at the top part to be in contact with the workpiece (workpiece) 30 first.

  Conventionally, the radius of curvature of the top of the thread of the movable round die is uniform. In this case, in the movable round die, the largest load is applied to the part that first contacts the workpiece (work) (contact start part), and the thread in this part is more likely to chip than the thread in the other part. There is a tendency for the lifetime to be shortened.

  In the present embodiment, the radius of curvature R1 of the top portion 23X of the part 22X of the thread 22 at the contact start portion with respect to the workpiece (workpiece) 30 is made relatively larger than the radius of curvature R2 of the top portion 23Y of the other portion 22Y. Yes. In this case, the contact area of the movable round die 20 that first contacts the workpiece (workpiece) 30 can be relatively increased. As a result, in the movable round die 20, it is possible to reduce the load applied to the contact start portion with respect to the workpiece (workpiece) 30, and to suppress the chipping of the screw thread 22 at this portion, thereby extending its life.

  As described above, in this embodiment, if the curvature radius R of the top portion 23X of the part 22X of the thread 22 is R1, and the curvature radius R of the top portion 23Y of the other part 22Y of the thread 22 is R2, R1> R2. That is, R1 / R2> 1.

  As described above, according to the present embodiment, it is possible to provide a rolling process method capable of extending the life of the movable round die 20 having the thread 22 on the outer peripheral surface 21.

The present invention is not limited to the above-described embodiment, and design changes can be made as appropriate without departing from the spirit of the present invention.
In the above embodiment, one of the pair of round dies 10 and 20 is fixed and the other is movable. However, both of the pair of round dies 10 and 20 may be movable. In this case, with respect to both of the pair of round dies 10, 20, the curvature radius R of the top portion 23X of the part 22X of the thread 22 that first contacts the workpiece (workpiece) 30 is set to that of the top portion 23Y of the other portion 22Y. What is necessary is just to make it relatively larger than the curvature radius R.

DESCRIPTION OF SYMBOLS 1 Rolling processing apparatus 10 Fixed round die 20 Movable round die 21 Outer peripheral surface 21X A part of outer peripheral surface 21Y The other part 22 of an outer peripheral surface 22 Thread 22X A part of a thread 22Y The other part 23X, 23Y of a thread

Claims (1)

Using a rolling processing apparatus provided with a pair of rotatable round dies having a thread on an outer peripheral surface, wherein at least one of the pair of round dies is a movable round die whose position with respect to a workpiece is variable. A rolling process method for performing a rolling process on the workpiece by pressing the movable round die against an object while rotating the workpiece,
In the movable round die, the radius of curvature of the top of a part of the thread is relatively larger than the radius of curvature of the top of the other part of the thread,
A portion of the thread having a relatively large radius of curvature at the top is first brought into contact with the workpiece;
Rolling processing method.

Images