JPS62208831A - Production of non-circular piston ring - Google Patents

Abstract

PURPOSE:To produce a high-precision piston ring with high efficiency at a low cost by performing a ring inner periphery forming process, a ring outer periphery forming process, and an abutment machining process in sequence in producing the non-circular piston ring of an internal combustion engine. CONSTITUTION:An endless-ring raw material 4 with an elliptical shape or similar to it and having parallel and flat planes on upper and lower end faces 5 is formed by casting or press machining, many of them are stacked and inserted on a clamp jig, and the peripheral face 6 is formed and machined by the broach 13 of a broaching machine. Next, a supporting jig 15 with the same cross section shape as this peripheral face 6 is inserted, and they are fitted to the table of a machining center 14 at the tip section of a works over arm 21 via a clamp washer 19 at the top of a clamp member 18. A milling cutter 24 supported by an over arm 23 is fed in the direction X, the work 4 is machined after the shape of the outer periphery 6 by an NC or profile control while being rotated around a shaft A, and finally an abutment 8 is formed by a slotting milling cutter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a piston for internal combustion IarIA whose cross-sectional shape is a non-circular long shape drawn by a smooth leap line such as an oval shape or an ellipse. The present invention relates to a method of manufacturing a non-circular piston ring to be fitted into a certain piston.

In a normal internal combustion engine, the cross-sectional shape of the piston is circular, so the outer periphery of the piston ring can be cut simply by applying a knife to the circumferential surface of the ring material and cutting it while rotating the ring material. The surface can be formed into a cylindrical surface of the required dimensions, and machining of the screw ring that fits into the piston is relatively simple.

(11) However, in internal combustion engines in which the cross section of the piston is formed into a non-circular elongated shape in order to increase the frontage area of the intake and exhaust valves of multi-cylinder internal combustion engines and improve the engine intake and exhaust efficiency, the ring material is Simply rotating the ring material makes it impossible to cut the ring material into the required non-circular elongated shape, making it impossible to efficiently produce piston rings.

The present invention relates to a piston ring manufacturing method that overcomes these difficulties, and involves broaching the inner circumferential surface of an endless ring material to form the ring inner circumferential surface. After that, with a jig fitted to the inner circumferential surface of the endless ring material and the endless ring material fixed, the outer circumferential surface of the endless ring material is cut, and the endless ring N material is cut. Make a cut in the direction of the generatrix,
By forming an abutment, a non-circular piston ring can be formed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention illustrated in FIGS. 1 to 10 will be described.

The piston 1 has a cross section whose outer periphery follows a curve obtained by taking a base circle with continuous curvature changes as a base t, It curve and connecting points separated by a certain distance from the base curve in the normal direction thereof. Several piston ring vortices 2 are formed in parallel on its circumferential surface, and piston rings 3 are fitted into these piston ring grooves 2, respectively.

Further, as shown in FIGS. 5 and 8, the endless ring material 4 whose upper and lower end surfaces 5 are parallel planes and have an ellipse or a shape similar to an ellipse is formed by VI construction or press working.

Furthermore, a large number of endless ring materials 4 are sequentially fitted into the clamping jig 10 whose inner circumferential surface is elliptical or approximating an ellipse using a loading wheel, and this is placed on the table 12 of the broaching machine 11 via the contact plate 28. The broach 13 is placed in the endless ring material 4 from above, and the broach 13 is pulled down by a hydraulic cylinder (not shown) to perform broaching.

Note that the contact plate 28 supports the endless ring cord material 4 in the clamp jig 10 and is cut together with the endless ring material 4 by lowering the broach 13, thereby preventing the generation of cutting burrs due to cutting of the endless ring material 4. It looks like this.

Next, as shown in FIGS. 6, 9 and 10,
Inner peripheral surface 6 of endless ring material 4 subjected to broaching
The endless ring material 4 is fitted into the support jig 15 which has the same cross-sectional shape as , and is fixed integrally to the turntable 16 with the pins 1 to 17, so that the top of the support jig 15 and the clamp member 18 A clamp washer 19 having a U-shaped notch is fitted to the top, the clamp hydraulic cylinder 20 is put into a non-operating state, and the clamp member 18 is pulled downward by the spring force of the disc spring 29 via a bearing (not shown). An endless ring material 4 is held and held by a support jig 15 and a clamp washer 19. Further, the work over arm 21 is pulled down and the tip pivot portion 22 is attached to the clamp member 18.
By engaging the four upper ends of the four layers of the MOW-shaped resilling material, the four-layer MOW-shaped resilling material is assembled to the vertical machining center (a vertical NC milling machine may be used) 14.

After assembling in this way, the milling cutter 24, which is rotatably supported at both ends by the overarm 23 of the machining center 14, is rotated and moved appropriately in the X direction perpendicular to the center of rotation to adjust the position of the milling cutter 24 in the X direction. By appropriately turning the turntable 16 around the center line A of the clamp member 18 in accordance with the above, the outer circumferential surface 7 of the yM end-shaped ring material 4 can be formed into a shape approximating a predetermined ellipse. .

The cutting edge of the groove milling cutter 25 is applied to the long axis end on the enlarged side of the endless ring material 4 which has been formed with the inner circumferential surface 6 and the outer circumferential surface 7 and is fitted in a laminated manner on the support jig 15, and then By moving the endless ring material 4 in the generatrix direction, the abutment 8 is formed.
form.

In this way, a large number of endless ring materials 4 having the required dimensions and shapes can be manufactured at one time through the process.

Furthermore, when forming the inner circumferential surface 6 of the piston ring 3, the processing reaction force associated with broaching acts on the endless ring material 4 as tension, and the reaction force that tries to expand the endless ring material 4 is suppressed. Since the piston ring 3 is restrained by the clamp jig 1o, the processing accuracy of the inner circumferential surface 6 of the piston ring 3 is high. Moreover, since the inner peripheral surfaces 6 of a large number of endless ring materials 4 can be formed at once by one broaching process, productivity is extremely high.

Furthermore, after forming the inner peripheral surface 6 of the endless ring material 4, a support jig 15 is fitted to the inner peripheral surface 6 to restrain the endless ring material 4, and the outer peripheral surface 7 of the endless ring material 4 is Because it is formed, the processing accuracy is high.

Moreover, the angle of the support jig 15 around the A axis and the position of the milling cutter 24 in the X direction are determined by NC control or copying control so as to match the shape of the outer peripheral surface 7 of the piston ring 3, and the turntable 16 is rotated and the milling cutter 24 is driven, even if the outer circumferential surface 7 of the piston ring 3 deviates from a circular shape, the outer circumferential surface 7 of the piston ring 3 can be formed into a shape approximating a desired ellipse.

Furthermore, the long axis end of the enlarged side of the endless ring material 4, in which the inner circumferential surface 6J3 and the outer circumferential surface 7 of the piston ring 3 have been formed into the required accurate shape, is cut to a constant width with a groove milling cutter 25 to form an abutment 8. Because of this, the circumferential length of the piston ring 3 can be made to accurately match the required length.

In the embodiments shown in FIGS. 1 to 16, the outer peripheral surface 7 of the bismine ring 3 is formed in a surface parallel to the central axis of the piston 1, that is, a surface perpendicular to the end surface 5 of the piston ring 3. As shown in FIG. 11 or 12,
A spacer 26 of a constant thickness may be interposed between the endless ring materials 4, and the outer circumferential surface 7 of the endless ring materials 4 may be formed using a milling cutter 27 whose cutting edge is inclined with respect to the rotation axis. If a milling cutter 27 such as
It can be formed on a surface that forms an angle other than a right angle with the end surface 5 of the ring 3.

Further, in the embodiment, the endless ring wood 4 has upper and lower end surfaces 5
was formed into a parallel thin ring shape, but after forming the endless ring material 9 into a hollow cylindrical shape and forming the inner peripheral surface 6 of the endless ring material 4 by broaching, the hollow cylindrical endless ring was formed. The cable material 9 may be divided into thin pieces along its axial direction.

According to the present invention, since the inner peripheral surface of the endless ring wood is first broached, the tension applied to the ring material due to broaching can be borne by the endless ring material itself. Screw 1 - The inner peripheral surface of the shilling can be processed efficiently with high precision.

In addition, in the present invention, the outer circumferential surface of the ring thread material was cut while the jig was fitted and fixed on the inner circumferential surface of the endless ring material whose inner circumferential surface had been processed. The cutting reaction force directed toward the center of the ring material due to this can be borne by the jig, and the outer circumferential surface of the piston ring can be easily machined with high precision.

Furthermore, in the present invention, the abutment process is performed by making cuts oriented in the generatrix direction of the endless ring material whose inner and outer peripheral surfaces have been processed, so that the entire circumference of the ring can be accurately adjusted to a predetermined length. Matched non-circular piston rings can be produced.

As described above, according to the present invention, a non-circular piston ring can be efficiently manufactured with high precision, productivity can be improved, and costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is an 8% side view of an engine in which a piston is fitted with a non-circular piston ring manufactured according to the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 The figure is a schematic plan view thereof, FIG. 4 is a plan view of the non-circular piston ring, and FIG. 5 is a schematic diagram of the inner circumferential surface forming step in an embodiment of the manufacturing method for the non-circular piston ring of the present invention. 6 is a perspective view illustrating an outline of the outer circumferential surface forming process, FIG. 7 is a perspective view illustrating an outline of the abutment processing process, and FIG. 8 is a perspective view illustrating the inner circumferential surface forming process. FIG. 9 is a vertical cross-sectional side view, FIG.
FIG. 2 is a side view illustrating the outer circumferential surface forming process of another embodiment. 1... Piston, 2... Piston ring groove, 3...
・Piston ring, 4... Endless ring material, 5...
・End face, 6...Inner peripheral surface, 7...Outer circumferential surface, 8...Abutment, 9...Endless ring material, 10...Clamp jig, 11...Broaching machine, 12. ...Table, 13
...Brooch, 14...Machining center, 15
...Support jig, 16...Turntable, 17...
・Bolt nut, 18... Clamp member, 19...
Clamp washer, 20...Hydraulic cylinder, 21...
・Work over arm, 22... Pivotal part, 23...
Over arm, 24... Milling cutter, 25...
- Groove milling cutter, 26... Spacer, 27... Milling cutter, 28... Back plate, 29... Belleville spring. Agent: Patent attorney, Ebara, 2 other people z3 Figure 4 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] A method for manufacturing a non-circular piston ring, which includes the steps of forming a ring inner circumferential surface by broaching the inner circumferential surface of an endless ring material, and fitting a jig onto the inner circumferential surface of the endless ring material to form a broaching process. A ring outer peripheral surface forming step of cutting the outer peripheral surface of the endless ring material while the endless ring material is fixed, and an abutment processing step of forming a cut oriented in the generatrix direction of the endless ring material are sequentially performed. A method of manufacturing a non-circular piston ring, characterized in that: