JPH0813395B2 - Screw forming equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for forming a screw on a pipe material by plastic working.

(Prior art and problems) Conventionally, as one method of screw forming of this kind, a die having a desired forming thread groove is rotated, and a pipe material is adhered and fixed to the die to form a pressure roller with the die. There is a screw forming method in which a screw groove engraved in a mold is transferred to a pipe material by crimping in an axial direction at a relative speed corresponding to the screw pitch engraved in.

In this method, the screw groove engraved in the mold and the axial action of the pressure roller operate via separate drive paths, so the axial error of the pressure roller and the error of the screw groove pitch engraved in the die This causes scratches on the forming threads and causes uneven thickness of the forming threads.

For this reason, even if the pipe material is taken out after screw forming by such a screw forming method, after removing the pressure of the pressure roller against the pipe material, the pipe material or the mold is reversed and taken out. This causes the phenomenon of biting into the mold, causing scratches on the molding screw surface during removal.

In addition, there is a problem that the device becomes complicated and the cycle time until the screw forming is completed often becomes long.

Another method is to engrave a molding thread groove on the inner circumference of the mold and press the crimping roller against the inner circumference of the pipe material that is fixed to the inside of the mold to take out the pipe material. Adopts the method of taking out the pipe material by dividing the die after screw forming.

For this reason, there is a drawback that the mold dividing line for dividing the mold remains as a scratch on the pipe material.

(Means for Solving the Problem) The present invention has been made in view of the above-mentioned problems, and the positions corresponding to the centers of the forming screw thread shapes of the forming roller and the pressure bonding roller are always made to coincide with each other so that no axial deviation occurs. As an integrated structure, it was fixed to a mandrel, and at the same time the mandrel was rotated, and at the same time, the screw was formed by making relative movement in the axial direction corresponding to the screw pitch to be formed.

(Operation) The screw forming apparatus of the present invention fixes the forming roller and the pressure roller so that they can be integrally operated in the axial direction on the mandrel which rotates and makes relative movement in the axial direction so as to obtain a desired forming screw pitch. A screw capable of arbitrarily forming a forming thread to a desired thread height by always matching the position corresponding to the center of the forming thread shape of the pressing roller and changing the pressing amount of the pressing roller against the pipe material. It is a molding device.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an apparatus showing an outline of the present embodiment.
2 shows a sectional view taken along the line II-II, and FIG. 3 shows an enlarged view of the forming roller portion.

F is a frame of this device, M is a motor which is a drive source fixed to the frame, and R is a constant thread forming length and position from the forming start point to the forming completion point of the thread groove to be formed on the pipe material W. Therefore, it is a resolver for controlling the rotation start position and the rotation stop position of the motor.

B is a toothed belt that transmits the rotational force of the motor, and transmits power via the toothed belt B to the pulley 2 that fits into the spline of the mandrel 1 to rotate the mandrel.

A male screw S having the same pitch as the desired forming screw is engraved on a part of the mandrel, and the bush 3 is fixed to the frame.
A female screw that meshes with this male screw is engraved on the inner diameter of the. That is, the mandrel rotates one revolution and moves in the X-axis direction by the screw pitch.

The screw groove formed by the pressure roller 17 and the forming roller 18 is deformed by the spring back of the pipe material W. The screw guide 4 that holds and guides the pipe W formed by forming the pressure roller 17 and the forming roller 18 by estimating the approximate amount of this springback is fixed to the mandrel body by the positioning pin 6 together with the bracket 5, and is always constant. By maintaining the positional relationship of (1), the precision of the forming thread can be improved and the pipe material W can be easily detached from the screw guide 4.

The bracket 5 is provided with a lever support shaft 7, and the cam lever 8 and the crimping lever 11 press the cam follower 12 against the cam 9 with the leaf spring 13 around the support shaft 7 as a pivot.
Is configured to follow the cam shape, and the amount of cam lift is transmitted to the crimp lever 11 via the adjusting screw 10.

The movement of the crimping lever slides a slider 15 provided with an elongated hole that engages with this pin through the pin 14 in the Y-axis direction by the slide guide portion of the bracket 5 to obtain the desired forming screw when the maximum lift amount of the cam is reached. It is designed to be the mountain height.

A pressure roller 17 rotatably supported by a pin 16 is provided at the tip of the slider 15 so as not to give strong friction to the pipe material when the pressure roller is pressed against the pipe material.

Further, a screw guide groove having an outer diameter slightly smaller than the inner diameter of the pipe material W is provided with a screw guide groove, and a forming roller having a cross-sectional shape similar to the screw guide groove is formed at a position where the screw guide groove is integrated with the screw guide groove. 18 is rotatably supported by a pin 19. In addition, the pipe W is clamp lever 21 with the clamp jig 20 with a part of the flange of the pipe being prevented from rotating (not shown).
And the method of crimping and fixing with the eccentric cam 22 is adopted.

A cam gear 27 pivotally supported on the mandrel via a change gears 24 and 26 fixed to an intermediate shaft 25 from a change gear 23 engaged with a mandrel spline transmits a rotation slower than the mandrel rotation by a change gear train. To be done.

The cam 9 fixed to this cam gear is suspended on the bracket 5 by a half hanger 28 so that the cam 9 moves integrally with the bracket 5 in the X-axis direction, and is pivoted on a lever support shaft 7 provided on the bracket 5. Cam lever 8 held
The cam follower 12 provided at is capable of operating in synchronization with the cam 9 in the X-axis direction, and can form a forming thread corresponding to the lift of the cam.

A guide bracket 29 having an inner diameter slightly larger than the outer diameter of the pipe material is provided in order to suppress deformation of the pipe material other than the pressure roller pressing portion during screw forming.

 Next, the operation sequence of screw forming of this device will be described.

First, the clamp jig 20 that is suitable for the flange shape of the pipe W
The direction of rotation of the pipe material is fixed to and the pipe material W is crimped and clamped by the clamp jig by the clamp lever 21 using the eccentric cam.

Next, the mandrel 1 waiting on the Xl side in the X-axis direction is the motor M.
Drives to rotate and move in the Xu direction.

At this time, the rotation of the mandrel is decelerated by the gear train to rotate the cam 9. Thus, the pressure roller regulates the shape of the cam 9 to form a desired thread groove with the tube material sandwiched between the tube and the forming roller, and the resolver stops the motor at the desired screw forming position.

Next, the motor is operated in reverse, the mandrel is operated in the Xl direction, the motor rotation is stopped at the standby position, the thread-formed pipe material is taken out, and one cycle of thread forming is completed.

The present invention is not limited to the above embodiment, and design changes can be made within the scope of the present invention.

For example, instead of the screw guide 4 of the mandrel, there may be no guide groove for the guide, and a mandrel having an outer diameter smaller than the inner diameter of the screw after molding may be used, or a servomotor may be used instead of the resolver to control the rotation of the motor. Or
Design changes such as the use of hydraulic pressure to clamp the pipe material are possible.

In addition, when the axial backlash of the screw engagement between the male screw and the bush 3 is large, if the clamp jig is configured to add a spring or the like so that the amount of this backlash can be corrected in the Xu direction, after the screw is formed. When the mandrel starts reverse rotation in the Xl direction, it is possible to make highly accurate forming screws without giving unnecessary force to the pipe material caused by this backlash.

(Effects) The effect of the present invention is to make the position corresponding to the center of the forming thread shape of the forming roller and the pressure bonding roller coincident with each other by rolling the two rollers of the forming roller and the pressure bonding roller to perform screw forming. In addition, it is possible to perform screw forming without forming scratches with a small amount of power without giving strong friction to the pipe material during screw forming, and by operating the forming roller and pressure roller together with the mandrel,
Since the backlash of the drive system is suppressed to a minimum and the axial positional relationship between the forming roller and the pressure bonding roller is always constant, it is possible to perform thread forming with a uniform thickness on the pipe material with high accuracy and few scratches. I was able to do it.

Further, since the position corresponding to the center of the thread shape of the forming roller and the pressure bonding roller always coincides with each other, even if the pressure roller is reciprocally moved in the X-axis direction while the pressure roller is pressed against the pipe material, the screw thread groove is formed. The screw guide 4 has the effect of suppressing and straightening the spring back of the molding groove without the phenomenon of the displacement of the pressure roller and the sticking of the pipe material to the screw guide part, and it is highly accurate and versatile for pipe materials. It became a molding machine.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the apparatus showing the outline of the present embodiment, showing a state in which the screw forming is completed and the mandrel has moved in the Xu direction. FIG. 2 shows a sectional view taken along the line II-II in FIG. FIG. 3 is an enlarged view of the cross section of the forming roller portion, which is the main part of the apparatus. 1 …… Mandrel, 2 …… Pulley, 3 …… Bush, 4 …… Screw guide, 5 …… Bracket, 6 …… Positioning pin, 7 …… Lever spindle, 8 …… Cam lever, 9 …… Cam, 10 ...... Adjustment screw,
11 …… Crimping lever, 12 …… Cam follower, 13 …… Leaf spring, 1
4,16,19 …… Pin, 15 …… Slider, 17 …… Crimping roller,
18 …… Molding roller, 20 …… Clamp jig, 21 …… Clamp lever, 22 …… Eccentric cam, 23,24,26 …… Replacement gear, 25 …… Intermediate shaft, 27 …… Cam gear, 28 …… Hanger , 29 …… Guide bracket, B …… Toothed belt, F …… Frame, M …… Motor, R …… Resolver, S …… Male thread, W …… Pipe material, X, Xl, Xu, Y…
… Arrow direction

Claims (1)

[Claims] 1. A part of a thread shape of a screw guide for performing a relative rotation in an axial direction and a desired forming screw pitch and for correcting and guiding a deformation of a screw groove formed by being inscribed in an inner diameter of a pipe material. A mandrel with a screw guide that pivotally supports the forming roller is installed at the position where the mandrel is integrated with the mandrel on the outer periphery of the pipe at a position where the center of the pipe and the center of the forming roller can be actuated arbitrarily. A screw forming apparatus for forming a thread groove having a desired forming thread height by operating a mandrel to operate a sandwiched pipe material in a direction of pressing the pressing roller against a forming roller by a pressing roller that operates in relation to each other.