JPS60261625A - Forming method of wheel rim - Google Patents

Abstract

PURPOSE:To improve the deflection accuracy of a rim by executing initial forming by approaching both forming rolls at a very low speed, and subsequently, approaching both the forming rolls at a high speed. CONSTITUTION:When a work 22 is installed onto a bottom roll 9, a servovalve 30 is operated by a signal of an electronic control unit 35, and the hydraulic pressure is supplied to a cylinder chamber 14a. Therefore, the roll 9 rises at a high speed, and when the work 22 contacts an upper roll 8, it is decelerated to a very low speed of 0-10mm./sec by a signal of a potentiometer 34. The roll 9 which is rising at a very low speed executes initial forming of the work 22 between the roll 8 and itself. Subsequently, the regular forming is executed by controlling the valve 30 and accelerating the rising speed of the roll 9. According to this method, the centering accuracy of the work is raised, and accordingly, the deflection accuracy of a rim is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for forming a wheel rim that significantly improves the so-called run-out accuracy of the rim when forming the wheel rim using a roll forming machine. .

[Conventional technology]

FIG. 4 is a perspective view of a roll forming machine widely used for forming wheel rims, with parts cut away and removed.

Here, a shaft 8 rotatably supported by the main body 1 via a fixed block 2 is projected toward the front side of the main body l, and a shaft 5 rotatably supported by the main body l via an elevating block 4. These shafts 8 and 5 are offset from each other, and the shafts 8 and 5 are synchronously driven in opposite directions by a hydraulic motor 6.7 installed on the back side of the main body 1. And @8
An Atsuhar roll 8 is attached to the shaft 5, a bottom roll 9 is attached to the shaft 5ilv, and the bottom roll 9 is replaceable.

Here, the lifting block 4 is slidably supported by the main body 1 so as to move up and down along a vertical plane passing through the center line of the shaft 8.5.This lifting block 4 has a link IOK, a torque accelerator Spindle 11vc butt, lever 12
connected to. On the other hand, this torque accelerator spindle 1
1 is pivotally supported by the main body 1 and connected to a spindle lifting cylinder 14 via a lever 18 protruding from the main body 1.

Therefore, the Uvindle lifting cylinder 14. When the piston rod is retracted by actuation of , the lifting block 4 and the shaft 5 are lowered under the action of the levers 12.18 which are out of phase with each other, and conversely when the piston rod is advanced,
Lifting block 4 and shaft 5 are raised.

Also, here, a pair of side guide rolls 15° 15 (0 in the figure only shows one side guide roll 15) are provided on both sides of the vertical plane passing through the center of the shaft 8.5. is rotatably supported by a hydraulic cylinder 17 by a bottle 16, and blocks 2, 4
In addition, the hydraulic cylinder 17it, which is located near the
The ends on which the roll 15 is attached are inclined towards the vertical plane, and their actuation moves the roll 15 towards or away from the vertical plane. Further, the pair of side guide rolls 15.15 moved in this manner are arranged in the vertical plane as follows:
The ring-shaped workpiece is always in a symmetrical position and thus rolls into contact with the surface of the ring-shaped workpiece mounted on the bottom roll 9, so that the workpiece is positioned so that its center line, 1, is located within the vertical plane during roll forming. Guide. 1 Also 18.19 in the figure
20 and 21 respectively indicate tessellation valves for raising and lowering the shaft 5 and the bottom roll 9, which are provided in association with the spindle lifting cylinder 14, and 20 and 21 respectively indicate a solenoid valve and a manually variable flow control valve. Figure 5 shows spindle lifting cylinder 1
4 is a hydraulic circuit diagram showing the connection state of each of these valves to 1.4, and this hydraulic circuit includes cylinder side chambers 14a and 1. .

and the rod side chamber 14b respectively with the solenoid valve 20.
The ascending and descending deceleration valves 18 and 19 are connected in series between the solenoid valve 20 and the cylinder side chamber 14a, and the flow control valve 21 is connected in series.

It is connected in parallel to the rising deceleration valve 18.

In roll forming using such a forming machine, the ring-shaped work 22 is first mounted on the bottom roll 9, and then the spindle lifting cylinder 14 is moved.

(8) During this raising operation of the bottom roll 9, the bottom roll 9 and the wall 22 are raised toward the upper roll 8 by the extension operation.
are rotated in opposite directions by hydraulic moders 6.7, and the workpiece 22 is formed into the desired final shape while being rotated by both rolls 8.9. Also work 2
2 is guided along its multiple circumferential surfaces by side guide rolls 15, 15 and positioned so that the center of the workpiece is within a vertical plane +1. passing through the centers of the shafts 8, 5.

After the roll forming is completed, the bottom roll 9 is lowered from its upper limit position to its lower limit position by the contraction operation of the spindle lifting cylinder 14, where the formed workpiece z
2 is removed from the bottom roll 9, and then the next workpiece is roll-formed in the same manner as described above.

[Problem that the invention seeks to solve]

However, in such a conventional technique, the elongation speed of the spindle lifting cylinder 14, or in other words, the lifting speed of the bottom roll 9, is equal to the lifting deceleration speed, as is clear from FIG. (It is controlled by the action of the valve 18 and the manual variable flow control valve 21, and the rising speed changes as shown in Fig. 6, so there is a problem that the so-called runout accuracy of the rim is low. In other words, the bottom roll 9 is raised at a relatively high speed by the action of the lifting deceleration valve 18 until it reaches the position just before the bottom roll 9 contacts the workpiece 22. In the manually variable Although the rising speed of the bottom roll 9 is reduced by the action of the flow control valve 21, the minimum allowable flow rate of the flow control valve 21 is determined by the variable throttle reed in the deceleration valve 18 for the purpose of increasing molding efficiency. ,.

Catechism to sufficiently reduce the rising speed of the bottom roll 9 because it is set thicker than that of 18b;
However, since the flow control valve 21 is manually variable, it is not possible to finely adjust the rising speed of the bottom roll 9, in other words, the flow rate, so the rising speed of the bottom roll 9 at the start of forming the workpiece 22 is Due to the rapid collision of the workpiece 22 with the upper roll 8 due to excessive speed and subsequent initial forming at a relatively high speed, the specific portion 1 in the circumferential direction of the workpiece 22
・Since a large plastic deformation occurs inward in the radial direction, and this local deformation is not completely corrected even at the end of roll forming, ・Furthermore, accurate centering of the workpiece 22 is not performed. Therefore, there was one problem in that it was not possible to improve the silence and dynamic balance of the rim.

[Purpose of the invention]

, :1 This invention provides a method for forming a wheel rim that advantageously solves the problems of the prior art,
Based on the new forming emulsion, 4°, of forming rolls that have a pair of opposite sides, when roll forming wheel rims, we can sufficiently improve the run-out accuracy of the rim and effectively reduce the drop in forming work efficiency. It is intended to prevent

[Means and effects for solving the problems] The method for forming a wheel rim of the present invention particularly involves performing initial forming while bringing a pair of forming rolls close to each other at a slow speed of, for example, 0 to 10 mm/seb. After the initial forming is completed, the forming roll is sped up, for example, 1. so that the load on the forming roll becomes a predetermined constant value. .

It consists of forming a lower heap.

An advantage of this forming method is that the rapid collision of the workpiece with the forming roll is prevented by reducing the approaching speed of the forming roll at the time of initial forming on the workpiece, more preferably from the point just before the start of initial forming, and the workpiece is formed after forming. - Since the workpiece is gradually pressed against the workpiece, local deformation does not occur at a specific position in the circumferential direction of the workpiece.

Moreover, since the deceleration and proximity of the forming rolls is maintained until the initial forming is completed, uniform initial forming is performed over the entire circumference of the workpiece, and accurate centering of the workpiece with respect to the forming rolls is performed. □Furthermore, since the approaching speed of the forming roll increases after uniform initial forming of the workpiece is completed, the efficiency of the forming operation does not decrease.

〔Example〕 The present invention will be explained below based on the drawings.

FIG. 1 is a graph showing an embodiment of the present invention, and this graph is related to forming force and emotion, with time on the horizontal axis and displacement of the bottom roll 9 on the vertical axis. Now, let's talk about Tameni, which provides compatibility with conventional technology.
Although the bottom roll 9 is displaced in the direction of the upper roll 8, the present invention is not limited to a method for displacing the upper roll 8, a method for displacing both rolls 8.9, and a pair of openings. In the figure, a is the point where the workpiece 22 and the upper roll 8 come into contact, b is the end point of the initial forming of the workpiece 22, and C is the initial point. d indicates the end point of the main forming 2.1 following the forming, and d indicates the end point of processing the workpiece 22.

In this example, bottom roll 9 is located just before contact point a.
is raised at a relatively high speed, for example, 100 mm/sec, and then the bottom roll 9 starts to fully decelerate, and the rising speed of the bottom roll 9 is increased from θ to the contact point (a) and the initial forming end point (bt). l Q mm/
The speed is 5f30.

As a result, the contact between the workpiece 22 and the upper roll 8 is made very gently, so that the word roll 22 is often locally severely deformed inward in the radial direction. During this slow rise that continues for .5 to 1.08 ec, the workpiece 22 is moved by the side guide roll 15. Accurately centered under '150 action.

Therefore, the runout accuracy of the wire 22 after molding is significantly improved.

Then, after the initial forming of the workpiece 22 is finished, the rising speed of the bottom roll 9 is increased during the time at the one-piece forming end point 0, in other words, until the bottom roll 9 reaches its upper limit position. This brings about an improvement in molding efficiency. Note that if the rising speed of the bottom roll 9 during this period is controlled so that its rotational speed is within a predetermined range, the roll load, or in other words, the external forming force applied to the workpiece 22 during this main forming, will be approximately constant. Therefore, the workpiece 22 can be uniformly molded over its entire circumference without local deformation of the workpiece 22.

Furthermore, from the end of the main forming to the processing end point) d, the bottom roll 9 is maintained at its upper limit position 1... and both rolls 8 and 9 are maintained in a rotating state to form the workpiece 22. Note that the appropriate time from the main forming end point ○ to the machining end point cl varies depending on the size of the workpiece 2z and other factors, but is, for example, 1° 0.8 to 1. It can be OSeC.

After the required roll forming of the workpiece 22 is completed in the above manner, the rotation of the rolls 8 and 9 is stopped (), and the bottom roll 9 is lowered to the lower limit position. The descending speed of 2,.

In the vicinity of the lower limit position, the impact is reduced to □ as shown in the figure to alleviate the impact. Figure 2 shows an example of a control circuit for producing the above-mentioned forming motion, and the broken line in the figure indicates an electric signal circuit, and a solid line indicates a hydraulic circuit. Here, the cylinder side chamber 14a of the spindle lifting cylinder 14 and the working rod side chamber 14b are arranged in parallel to each other using a servo pulp 80 and a solenoid pulp for moving down. 81 to a hydraulic power source 82, and an electronic control unit) B5i to a tachometer 88 provided in connection with the bottom roll 9 and a potentiometer 84 provided in connection with the spindle lifting cylinder 14. An electronic control unit 85 is connected to the solenoid 1 of each pulp 80,81.

Here, this electronic control unit 85 controls the pulp 80 based on the signals from the tachometer 88 and the potentiometer 84.
．． 81. In such a control circuit, the bottom roll 9 is operated to control the operation of the bottom roll 9.

When the workpiece 22 is mounted, the servo pulp 80 is activated by a signal from the electronic control unit 85.
Hydraulic pressure from a hydraulic source 82 is supplied to the cylinder side chamber 14a of the spindle lifting cylinder 14 via the servo pulp 80. Due to this, the bottom roll 9 is, for example, 10011m/S6! The bottom roll 9 will be raised at a high speed of about 0. This high-speed raising of the bottom roll 9 will continue until just before the work 22 contacts the upper roll 8, and when the work 22 reaches the position just before that, the bottom roll 9 will be raised at 11. The signal from the potentiometer 84 is input to the electronic control unit 85, and the electronic control unit 85 outputs a deceleration signal to the servo pulp 80. As a result, the rising speed of the bottom roll 9 is such that the workpiece 22 is lower than the upper roll 8. Immediately before contact with
This slow speed increase of the bottom roll 9 becomes a minute speed of ~10 mm/sec. In other words, the bottom roll 9 increases at a minute speed until the initial forming of the workpiece 22 is completed, under the action of a timer built in the electronic control unit 85, for example...0. 5-1.
Oseo maintained tel.

After the initial forming of the workpiece 22 is completed, the electronic control unit 85 causes the servo pulp 81 to be made 11b to increase the rising speed of the bottom roll 9, and also controls the rotation of the bottom roll 9 in response to a signal from the tachometer 88. The operation of the servo pulp 80 is controlled so that the number falls within a predetermined range. When the bottom roll 9 reaches its upper limit position, this is also controlled by a timer built in the electronic control unit 85, for example, 0. 8-1. OfE8c between 1・
” After this period of time has passed, the electronic control unit 85 moves the servo pulp 80 to the closed port position shown in the figure, and turns the lowering solenoid pulp 81
is activated to start discharging oil from the cylinder side chamber 14a of the spindle lifting cylinder 14. As a result, the bottom roll 9 starts descending at a relatively high speed as shown in FIG. The high-speed descent continues until the bottom roll 9 reaches a portion near its lower limit position.Then, when the bottom roll 9 reaches a portion near its lower limit position, the electronic control unit 8
5 places the lowering solenoid valve 81 in the closed boat position shown by the signal from the potentiometer 84 and again activates the servo pulp 80, resulting in a significant reduction in the lowering speed of the bottom roll 59.

FIG. 8 is another control circuit diagram, and in this example, the cylinder side chamber 14a and the rod side chamber L4b of the spindle lifting cylinder 14 are connected to a proportional control valve 8 disposed in series with each other.
6 Solenoid pulp 111B7 are sequentially connected to a hydraulic power source 82, and a potentiometer 84 provided in association with the lifting block number is connected to an electronic control unit 85 connected to a proportional control valve 86.

The electronic control unit 85 here controls the operation of the proportional control valve 86 based on the comparison result between the signal from the votentometer 84 and the preferred molding motion inputted to the control unit 85 in advance. 11.
, Yo, □, Nio 7, ka.

If the processing motion is previously input to the electronic control unit 85, the four-dimensional forming processing motion will be produced according to each position of the lifting block 4 and thus of the bottom roll O.

According to this example, although it is not possible to directly control the rotation speed of the bottom roll 9, when the rotation speed of the bottom roll 9 is specified, its increasing speed can be determined based on the relationship between the rotation speed of the bottom roll 9 and the displacement amount of the bottom roll 9. By inputting the information to the electronic control unit 85 below, the rotation speed can be indirectly controlled.

This invention has been explained above based on the illustrated examples. 1. The bottom roll rising speed during initial forming on the workpiece, the initial forming time, the bottom roll rotation speed during the main forming, etc. [Effects of the Invention] Therefore, according to the present invention, when the workpiece is initially formed, the approaching speed of the pair of forming rolls is set to a very slow speed, so that the workpiece is formed at a very low speed. It is possible to prevent local deformation of the workpiece in the radial direction due to sudden collision with the forming roll, and
Centarin of the work,.

In addition, by increasing the approaching speed of the forming rolls during main forming after the initial forming,
Decrease in molding work efficiency can be sufficiently prevented. In addition, if the roll rotation speed during main forming is maintained within a specified range, more uniform roll forming can be performed all around the workpiece◇

[Brief explanation of the drawing]

Fig. 1 is a graph illustrating the forming motion according to the present invention, Fig. 2.8 is a control circuit diagram for realizing the processing motion shown in Fig. 1, and Fig. 4 is a known roll forming method. 5 is a conventional control circuit diagram, and FIG. 6 is a graph showing the molding motion brought about by the control circuit shown in FIG. 5. 8...Top roll 9...Bottom roll 10...
Link 12.18... Lever 14... Spindle lifting cylinder 22... Work 80... Servo valve □81.
・・Lowering solenoid pulp 82 ・・Hydraulic pressure source 88 ・・Tachometer 85 ・・Electronic control unit 86 ・・Proportional control valve 87
...Solenoid valve a...Contact point b...Initial molding end point C...Main molding end point) (1...Processing end point. Patent applicant Nissan Motor Co., Ltd.

Claims (1)

[Scope of Claims] When forming a ring-shaped workpiece attached to one of the forming rolls, the forming rolls are brought close to each other at a very slow speed by the close operation of forming rolls that form a pair and are driven to rotate. A method for forming a wheel rim characterized by 1. Performing initial forming while moving, and then performing main forming by rapidly bringing both forming rolls close to each other.