JPS6344448B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) A roll forming device according to the present invention continuously bends and forms a strip-shaped metal plate (workpiece) fed in the length direction across the width direction to form a piston ring or the like. Used to make various edge metals, precision parts for OA equipment, etc.

(Background of the Invention) For example, a piston ring spacer having an annular shape as shown in FIG. 1 and a cross-sectional shape as shown in FIG. 2 is manufactured by bending a metal plate having a shape as shown in FIG. It will be done. The workpiece 2, which is a metal plate, is first bent into a cross-sectional shape as shown in FIG. 2 before being formed into an annular shape as shown in FIG. Each set is carried out continuously using a plurality of rolls arranged in series with each other.

To briefly explain such a roll forming operation with reference to FIG. 4 showing an embodiment of the present invention,
Workpiece 2 being fed from the right end of the diagram to the left
is formed into a cross-sectional shape as shown in FIG. 5 while passing through the first set of rolls 3a, 3b and the second set of rolls 4a, 4b, and then passed through the third set of rolls 5a, 5.
b. While passing through the fourth set of rolls 6a and 6b, it is formed into a cross-sectional shape as shown in FIG. This workpiece 2 is further formed into a cross-sectional shape as shown in FIG. 7 while passing through the fifth set of rolls 7a and 7b.
Furthermore, the cross-sectional shape as shown in FIG. 8 formed by the sixth set of rolls 8a and 8b, and the seventh set of rolls 9
The cross-sectional shape shown in FIG. 9 is formed by rollers a and 9b, and then the cross-sectional shape shown in FIG. 10 is formed by the eighth set of rolls 10a and 10b. The workpiece having the cross-sectional shape shown in FIG.
Furthermore, the ninth set of rolls 11a, 11b, the tenth set of rolls 12a, 12b, and the eleventh set of rolls 13a, 1
3b, the workpiece is formed into the cross-sectional shape shown in FIG. 2 by each of the 9th to 11th sets of rolls and a set of two side rolls 15, 15a that press the workpiece from the lateral direction.

However, when a workpiece is simply bent between two or more sets of rolls as in the past, the following problems occur. In other words, when a workpiece is bent and formed by roll forming, the surface that does not come into contact with any roll surface unless the cross-sectional shape after forming is an L-shape or a simple shape such as a semicircular arc. It is inevitable that this will occur. For example, when a workpiece having a cross-sectional shape as shown in FIG. 10 is further roll-formed into a cross-sectional shape as shown in FIG. 2, the side rolls 15 and 15a are The metal plate 2 is pressed from the left and right sides, and the surface drawn with thick lines in FIG. 10 does not come into contact with any of the roll surfaces, leaving a cavity inside the thick lines. Therefore, when a set of rolls presses the workpiece 2 in the direction of the arrow in FIG. 10 and attempts to bend the workpiece 2 into the cross-sectional shape shown in FIG. causing deformation to escape towards the inside of the cavity,
It becomes difficult to perform accurate bending that matches the surface shape of the roll. This amount of deformation is not that large and does not pose much of a problem under normal circumstances, but in the case of piston ring spacers and other precision parts, even a slight distortion in the cross-sectional shape will result in a defective product, so it is subject to damage during molding. Parts of the workpiece must be prevented from escaping into the cavity. For this reason, a core material called a mandrel has conventionally been used to prevent the workpiece from escaping into the cavity. However, conventional mandrels are of a fixed type, and the workpiece formed by rolls is fed while slidingly contacting the surface of the mandrel, so that a frictional force is generated between the workpiece and the mandrel. This frictional force increases in proportion to the force applied from both sides by the rolls, so when the pressing force from the rolls is increased in order to perform precision machining, the frictional force that acts between the mandrel and the workpiece increases. becomes excessive, causing damage to the mandrel, failure of the roll drive mechanism, and even abnormal deformation of the workpiece.

(Object of the Invention) An object of the present invention is to provide a roll forming device that can eliminate the above-mentioned disadvantages and smoothly perform precise roll forming without friction between the mandrel and the workpiece. It is said that

(Structure of the Invention) The roll forming apparatus of the present invention has an endless ring-shaped mandrel that prevents deformation of a metal plate during roll forming of the metal plate as a workpiece, and a hollow space in the metal plate between the forming rolls. The structure is such that the mandrel entering the inside of the metal plate can move together with this metal plate.

For this reason, the mandrel can completely prevent the metal plate from deforming inward when it is formed by rolls, and since the mandrel and the metal plate do not rub against each other, the mandrel No excessive force is applied to the rollers or rollers.

(Embodiments of the Invention) Next, the present invention will be explained in more detail while explaining the illustrated embodiments.

FIG. 4 shows an apparatus for forming a belt-shaped workpiece into a predetermined cross-section by roll forming, and then coiling the entire workpiece into an annular shape. 1st set roll 3
The workpiece is pressed in the vertical direction in FIG. 4 by the eighth set of rolls 10a, 10b starting from
The parts up to the cross-sectional shape shown in the figure are the same as those of the conventional device. In the roll forming apparatus of the present invention, the workpiece 2, which has a cross-sectional shape as shown in FIG. Side rolls 15, 15a and the ninth set of rolls 11 to be formed into
a, 11b, 10th set of rolls 12a, 12b, 1st roll
A direct portion of the elliptical and endless mandrel 14 is located in the area between the 11 sets of rolls 13a and 13b. That is, two or more sets of guide rollers 1 are provided with flexible mandrels 14 whose cross section almost corresponds to the cross section of the cavity inside the workpiece after roll forming.
6 and 16, and has an oval shape in which two semicircular arc portions and two direct portions are alternately continued, and one straight portion of this mandrel 14 is supported by the ninth set of rolls 11a and 11b. Between,
Between the 10th set of rolls 12a and 12b, the
It is sandwiched between 11 sets of rolls 13a and 13b, and between each side roll 15, 15a. The lower side of this endless mandrel 14 is
It is fed from right to left in FIG. 4 and enters the inner cavity of the workpiece from the opening side (upper side of FIG. 10) of the workpiece whose cross section is formed into a substantially U-shape.
It moves together with the metal plate which is moved to the left in FIG. 4 by the side rolls 15, 15a and the 9th to 11th sets of rolls.

In the illustrated example, among the two sets of side rolls 15, 15a, the first set of side rolls (the right side roll in FIG. 4) 15, 1
5a to form the cross-sectional shape shown in FIG. 10 to the cross-sectional shape shown in FIG.
5 and 15a to form the cross-sectional shape shown in FIG. The cross-sectional shape shown in FIG.
This corresponds to the cross-sectional shape of the piston ring spacer 1 shown in the figure. When forming the workpiece 2 into the cross-sectional shape shown in FIG. Because the mandrel 14 has entered inside, the workpiece 22
The wall surface of the workpiece 2 is not deformed toward the inside of the cavity, and the cross-sectional shape of the workpiece 2 can be formed accurately as desired. Further, as the workpiece 2 moves, the mandrel 14 supported by the guide rollers 16, 16 circulates clockwise in FIG. 4 as shown by the arrow in the figure. The workpiece 2 does not rub strongly against each other, and no excessive force is applied to any part of the molding device. After forming the workpiece 2 into a predetermined shape, the mandrel 14
is pushed out from the cavity of the workpiece 2 by a peeling shoe 28 provided behind the eleventh set of rolls 13a, 13b, and only the workpiece 2 is sent to a coiling device to be described later. Also, in Figure 12, 29
The upper guide 30 enters the upper end of the cavity of the workpiece 2 being fed between the rolls and prevents the workpiece 2 from shifting in the lateral direction. This is a lower guide that prevents the workpiece from shifting downward.

The workpiece 2 whose cross section has been formed into a predetermined shape is then formed into an annular shape as shown in FIG. 1 to be used as a spacer for a piston ring, but in the embodiment shown in FIG. 4, it is roll formed. Rear part of the device (4th
A coiling device is provided at the left end (in the figure) for forming a workpiece into an annular shape to form a spacer for a piston ring. This coiling device is the 13th
As shown in the enlarged figure, a pair of upper and lower rolls 1
7, 18, a bending ring 19 (slightly smaller diameter than the piston ring spacer after completion) that rotates between the rolls 17, 18, and a bending shoe 20 that deforms the workpiece toward the bending ring 19. , rollers 21 and 21 that press the workpiece 2 after passing through the bending shoe 20 onto the outer peripheral surface of the bending ring 19, and rollers 21, 21 that press the workpiece 2 that has passed through the bending shoe 20 onto the outer peripheral surface of the bending ring 19; Scraper 2 for removal
It consists of 2. A pair of upper and lower rolls 17,1
As shown in FIG. 14, a convex portion 23 is formed in the center portion of the outer circumferential surface of the upper roll 17 of the rolls 8, and this convex portion 23 is engaged with a groove 24 formed on the inner circumferential surface of the bending ring 19. This bending ring 19 is prevented from shifting in the lateral direction (front and back directions in FIG. 4, left and right directions in FIG. 14). Further, the workpiece 2 is placed on the outer periphery of the bending ring 19.
A convex portion 25 is formed into the cavity which is open to the inner circumferential side. On the other hand, the outer peripheral surface of the lower roll 18 has a groove 26 into which the workpiece 2 can just freely enter.
is formed. The bending shoe 22 is the bending ring 1
9 and the roll 18, the workpiece 2 is pressed against the outer peripheral surface of the bending ring 19, and the workpiece 2 is formed into an annular shape that matches the outer diameter of the bending ring 19. The surface 20a facing the outer peripheral surface of the bending ring 19 is an arcuate surface. Since the bending of the workpiece 2 is insufficient with only this bending shoe 22, the rollers 21, 21 press the workpiece 2 after passing through the bending shoe against the bending ring 19 to reduce the inner diameter of the workpiece 2. It serves to bring the outer diameter of the bending ring 19 closer to the outside diameter. scraper 22
The piston ring spacer, which has been bent into an annular shape and wrapped around the bending ring 19, is peeled off from the outer periphery of the bending ring 19 and dropped onto a product receiver or the like. In the drawing, 27 indicates the 11th set of rolls 13a, 27 when the workpiece is short.
Feed roll for smoothly feeding the workpiece after passing through 13b to the coiling device; 31 is a bending ring 1 pushed to the left in the drawing by rollers 21, 21;
This is a receiving roll that holds down 9 from the right side.

(Effects of the Invention) As described above, the roll forming apparatus of the present invention is provided with a mandrel that enters the cavity inside the workpiece and moves together with the workpiece, so that it can be used for precision workpieces. Molding work can be easily performed without friction with the workpiece unlike with conventional fixed mandrels, and the durability of the equipment is also improved because no excessive force is applied to any part of the molding equipment. It will be a win. In addition, low-cost mass production is possible by roll forming, even with precision cross-sections that were conventionally considered impossible.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a piston ring spacer as an example of a workpiece formed by the forming apparatus of the present invention, Fig. 2 is a sectional view of this spacer, and Fig. 3 is a metal before bending. Partial plan view of the board,
FIG. 4 is a schematic side view showing the overall configuration of the roll forming apparatus of the present invention, FIGS. 5 to 12 are end views of a workpiece showing the state in which metal plates are sequentially formed by this forming apparatus, and FIG. FIG. 4 is an enlarged view of part A, and FIG. 14 is an enlarged cross-sectional view taken along line B--B of FIG. 13. 1: Piston ring spacer, 2: Workpiece, 3a, 3b: Roll, 4a, 4b: Roll,
5a, 5b: roll, 6a, 6b: roll, 7
a, 7b: roll, 8a, 8b: roll, 9a,
9b: Roll, 10a, 10b: Roll, 11
a, 11b: roll, 12a, 12b: roll,
13a, 13b: Roll, 14; Mandrel, 1
5, 15a: side roll, 16: guide roller,
17: roll, 18: roll, 19: bending ring, 2
0: Bending shoe, 20a: Surface, 21: Roller, 2
2: Scraper, 23: Convex portion, 24: Groove, 25:
Convex portion, 26: Groove, 27: Feed roll, 28:
Peeling shoe, 29: upper guide, 30: lower guide.

Claims (1)

[Claims] 1 In a roll forming device in which two workpieces are passed between multiple sets of rolls to form the cross section into a desired shape, an endless roller is placed between the latter rolls located near the end of the forming process. A part of the mandrel, which is annular and flexible and has a cross-sectional shape that allows it to just enter into the cavity inside the molded workpiece, is held in between, and this mandrel is moved as the workpiece is fed by rolls. A roll forming device characterized by free circulation.