JPH01224569A - Manufacturing method for non-circular piston rings - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a piston ring for an internal combustion engine, and in particular to a method for manufacturing a piston ring for an internal combustion engine, and particularly for a non-circular piston that is fitted into a piston whose cross-sectional shape is elliptical or oval. The present invention relates to a method of manufacturing a ring.

BACKGROUND ART Multi-cylinder internal combustion engines are known that employ cylinder bores and pistons having an elliptical or oval cross-sectional shape in order to increase the opening areas of intake and exhaust valves to improve intake and exhaust efficiency. The non-circular piston ring that is fitted into the piston is difficult to machine due to its special shape.Compared to circular piston rings, it requires higher dimensional accuracy and is difficult to machine, resulting in longer machining time. (For example, Utility Model Application No. 59-70046, Utility Model Application No. 59-70046
(See Publication No. 24950). Conventionally, a non-circular piston ring has been obtained by cutting an annular cast product using a step-by-step NC milling machine, but this has been extremely uneconomical due to the high operating cost per unit time of the NC milling machine.

The purpose of the present invention is to improve the chewability mainly through plastic forming when manufacturing non-circular piston rings, and to reduce the time required to use an NC milling machine for finishing. The goal is to keep it short.

This objective is achieved by plastically deforming a linear piston ring material with a rectangular cross section using a forming roll that imitates and follows a master cam to give it an elliptical or oblong curved shape.

Hereinafter, the specific contents of the present invention will be explained based on examples.

A long linear piston ring material 1 having a rectangular cross section with a thickness of t9 and a width of W is prepared (Fig. 1). Examples of the shape of a piston ring obtained by curve-molding the piston ring material 1 are shown in FIGS. 2 and 3. The piston ring 2 is an elliptical body, and the piston ring 3 is an oblong body.

(2) A forming device 4 (FIG. 4) is used to plastically deform (curve forming) the piston ring material 1. The forming device 4 passes the linear piston ring material 1 sent by the wire feeding roll 5 between the master cam 7 and the forming roll 15 and sends it by a predetermined length, and then immobilizes the piston ring material 1 with a gripper 6. This is a device for gripping and rotating the cylindrical rotary arm 11 to move the forming roll 15 along the outer periphery of the master cam 7 in an immobile position, thereby imparting the outer periphery shape of the master cam 7 to the piston ring material 1. . The outer peripheral contour shape (more precisely, the contour shape of the groove bottom of the circumferential groove 8) of the master cam 7, which has a circumferential groove 8 for receiving the piston ring material 1 on its outer periphery, can be arbitrarily selected. 4
In the figure, the shape of the master cam 7 is selected so that the elliptical piston ring 2 shown in FIG. 2 can be formed.

The drive shaft 10 passes through the master cam 7 in an immovable position so as to be relatively rotatable, and is connected to the base end of the cylindrical rotary arm 11 so as not to be relatively rotatable. Therefore, when the drive shaft 10 is rotated, the cylindrical rotary arm 11 is rotated.

The cylindrical rotating arm 11 is formed as a cylindrical body with a square cross section,
The tip is closed with an end wall 12, and a vertically divided window 13 is formed in the front wall. Inside the cylindrical rotary arm 11, a first slider 14, which is a block-like hexahedron that supports the forming roll 15, and a compression coil spring 17 that biases the slider 14 toward the drive shaft 10 are stored. ing. The forming roll 15 supported by a support shaft 16 passing through the slider 14 has a vertically divided window 13
It protrudes to the outside of the cylindrical rotary arm 11 through the cylindrical rotary arm 11. The forming roll 15 is urged by the elastic force of the compression coil spring 17 and moves along the outer periphery of the master cam 7 while pressing the linear piston ring material 1 (Figs. 5 and 6).
figure).

Note that a notch 9 is formed at a longer diameter position on the outer periphery of the master cam 7 and is deeper than the groove depth of the circumferential groove 8, and this notch 9 is used to remove the piston ring material wrapped around the outer periphery of the master cam 7. 1 can be made (FIG. 4).

(2) The forming roll 15 before the linear piston ring material 1 is fed to the master cam 7 side by the wire feeding roll 5 is in contact with the outer periphery of the master cam 7 as shown in FIG. When the wire feed roll 5 is rotated to feed the piston ring material 1 in this state, the tip of the piston ring material 1 enters the circumferential groove 8 of the master cam 7 while resisting the elastic force of the compression coil spring 11. The forming roll 15 is pushed up and moved forward linearly while being sandwiched between the master cam 7 and the forming roll 15. When the length from the tip of the piston ring material 1 to the notch 9 position of the master cam 7 matches the circumference of the product piston ring, the wire feed roll 5 stops, and the gripper 6 immobilizes the piston ring material 1. Grasp (4th
figure).

■When the cylindrical rotary arm 11 is rotated by the rotation of the drive shaft 10, the forming roll 15 is biased by the compression coil spring 17.
moves along the contour of the master cam 7 while pressing the piston ring material 1 into the circumferential groove 8 of the master cam 7. FIG. 8 shows a state in which the cylindrical rotary arm 11 has been rotated by an angle of about 90 degrees from its initial position (FIG. 4), and FIG.
1 shows a rotated state.

■ Just before the rotation angle of the cylindrical rotary arm 11 from the initial position reaches about 270 degrees and the tip of the piston ring material 1 interferes with the proximal end portion (A) of the piston ring material 1, the drive shaft 10 is rotated. Stop it once. Next, the rotary cutter 18 is moved to cut the piston ring material 1 using the notch 9 formed on the outer periphery of the master cam 7. Thereafter, the cylindrical rotating arm 11 is rotated again to complete the curve forming of the piston ring material 1, thereby obtaining a piston ring having the shape shown in FIG. 2. In addition, when rotating the cylindrical rotating arm 11 again,
Piston ring material 1 toward master cam 7 at position B
Piston ring material 1 until the molding is completed by pressing
It is preferable to prevent misalignment.

Thereafter, the operations ① to ② are repeated to continuously form piston rings.

According to the method of this embodiment, piston rings can be obtained continuously by winding the long σ linear piston ring material 1 around the outer periphery of the master cam 7. Since it is only necessary to perform NG milling, the productivity is extremely high compared to the conventional method of applying NG milling to a cast product, and the yield is good because the piston ring material 1 is used as a wire rod. It is possible to plan for a significant reduction in manufacturing costs.

Note that the slider 14 may be biased using hydraulic pressure instead of the compression coil spring 17 in the embodiment described above.

Support 1” Shadow 2 ■Using the long linear piston ring material 1,
The point of obtaining elliptical or oval piston rings like the piston rings 2 and 3 shown in the figures is the same as in Example 1.

(2) A forming device 19 is used to plastically deform (curve forming) the piston ring material 1 (FIG. 10). Molding device 19
The piston ring material 1 fed by the wire gripper 22 is bent by a forming roll 29 that is linearly displaced along the slit 28 of the roll holding member 26 while being transferred in contact with the outer periphery of the rotating master cam 23. The piston ring material 1 has a predetermined piston ring shape.
This is a device for imparting. The drive rod 20 that supports the wire gripper 22 is equipped with a rack 21 at its tip.
It reciprocates in the direction of arrow C. Rack 21 is master cam 2
The reciprocating movement of the rack 21 causes the pinion 24 and the master cam 23, which are supported by the rotating shaft 25, to rotate reversibly. Note that the circumferential length of the binion 24 matches the circumferential length of the product piston ring.

The roll holding member 26 is a rotating plate-shaped master cam 2.
3 is sandwiched therebetween (FIG. 11), and the support shaft 30 engages with the linear slit 28 formed in the plate-like bodies 27 along the slit 28. The forming roll 29 is configured to be freely movable, and the forming roll 29 moves forward and backward as the master cam 23 rotates.

The fixed bins 31 and 32 have the function of stably feeding the piston ring material 1 and cooperating with the forming rolls 29 to curve-form the piston ring material 1.

■The piston ring material 1 gripped by the wire gripper 22 is sent along the fixed pin 31 as the drive rod 20 moves forward, and is guided along the tip guide piece 33 whose tip is movable and sent to the D position. It will be done. In this state, the movement of the drive rod 20 is stopped, the grip of the piston ring material 1 by the wire gripper 22 is released, and the drive rod 20 is moved in the backward direction. This operation causes the rack 21. master cam 23.
Forming roll 29 is set to the starting position shown in FIG.

■When the drive rod 20 is moved forward with the piston ring material 1 held by the wire gripper 22, the binion 24 that engages with the rack 21 rotates, and the master cam 23 also rotates at the same time, causing contact with the moving piston ring material 1. In this connection, the forming roll 29 is pressed against the outer periphery of the master cam 23, and the forming roll 29 is displaced along the slit 28 in accordance with the contour of the master cam 23. The displacement of the forming roll 29 determines the curvature of the piston ring material 1 to be formed, and when the curvature is large, the displacement of the forming roll 29. Due to the cooperation of the fixed bins 31, 32, the forming rolls 29. when the curvature is small. The piston ring material 1 is curved by the cooperation of the fixing pin 31. In addition, since the piston ring material 1 advances while being sandwiched between the two plate-like bodies 27 during the curved shape, the piston ring material 1 is unlikely to fall down due to deformation.

When the master cam 23 makes one revolution, the drive rod 20 is stopped and the piston ring material 1 is cut at the D portion, thereby obtaining a piston ring having a shape as shown in FIG. 2 or 3.

According to the method of this embodiment, an elliptical or oblong piston ring can be continuously obtained from a long linear piston ring material 1, and the piston ring can be subjected to short-time NC milling as necessary. NC is applied to the cast product.
The productivity is extremely high compared to the conventional method of milling, and since the piston ring material 1 can be used as a wire rod, the yield is good, and manufacturing costs can be significantly reduced.

In addition, in the above embodiment, the drive rod 20. Rack 21. Binion 24. Although the movement of the wire rod feed and the forming roll 29 were mechanically synchronized by a mechanism consisting of the master cam 23 and the wire gripping tool 22, the movement of the forming roll 29 was electrically synchronized with the wire rod feed using N CIQ 'IfJ, sequence control, etc. 29 may be moved.

As is clear from the above description, according to the present invention, a linear piston ring material is plastically deformed by a forming roller that imitates and follows a master cam to give an elliptical or oblong curved shape. It is possible to obtain piston rings efficiently, and the piston rings obtained by this molding can be subjected to short-time NC milling as necessary, which is superior to the conventional method of performing NC milling on cast products. Since the piston ring material is used as a wire rod, productivity is high, and the yield is good because the piston ring material is used as a wire rod, so it is possible to significantly reduce manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the tip of a linear piston ring material used to carry out the method of the present invention, FIGS. 2 and 3 are views showing examples of the shape of the piston ring obtained by the present invention, FIG. 4 is a schematic diagram showing a molding device as an example used to carry out the method of the present invention, FIG. 5 is a front view of a cylindrical rotary arm that is a component of the molding device, and FIG. 6 is a sectional view of the main part thereof. 7 is a front view of the main parts of the molding apparatus before the start of molding, FIGS. 8 and 9 are views showing the operation mode of the molding apparatus before the start of molding, and FIG. 10 is a front view of the main parts of the molding apparatus before the start of molding. FIG. 11 is a schematic view showing another molding apparatus used for carrying out the process, and FIG. 11 is a sectional view of a main part thereof. DESCRIPTION OF SYMBOLS 1... Piston ring material, 2, 3... Piston ring, 4... Forming device, 5... Wire feed roll, 6
... Gripping tool, 7... Master cam, 8... Circumferential groove,
9... Notch, 10... Drive shaft, 11... Cylindrical rotating arm, 12... End wall, 13... Vertical split window, 14...
・Slider, 15... Forming roll, 16... Support shaft, 1
7... Compression coil spring, 18... Rotary cutter, 1
9... Molding device, 20... Drive rod, 21... Rack, 22... Wire gripper, 23... Master cam,
24... Binion, 25... Rotating shaft, 26... Roll holding member, 27... Plate-shaped body, 28... Slit, 29... Forming roll, 30... Support shaft, 31 .32
...Fixed bottle, 33...Tip guide piece.

Claims (1)

[Claims] A method for producing a non-circular piston ring, which comprises plastically deforming a linear piston ring material having a rectangular cross section using a forming roll that imitates and follows a master cam to give it an elliptical or oblong curved shape.