JPS6174745A - Manufacture of piston ring made of steel - Google Patents

Abstract

PURPOSE:To improve the quality and accuracy of a ring by forming a ring material from a steel wire rod having circular sectional form, giving desired sectional form by press work and making work after tempering. CONSTITUTION:A wire rod 1 is coiled to true circular form using a jig 2 or a forming guide. The coiled wire rod is cut by a milling cutter to obtain a separate ring material 4a. The ring material 4a is die forged by a press 5 and a ring material 4b having desired sectional form is obtained. Then, after making tempering of quenching and tempering, final work is performed. By this method, no torsional deformation takes place, and the deformation of sectional form in press work is wholly corrected. Accordingly, both the quality and accuracy of the steel ring are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a steel piston ring (including a sight rail of a steel combination oil ring).

(Prior Art) Piston ring materials used in internal combustion engines, compression engines, etc. are currently being replaced by various steel materials instead of conventional cast iron materials. This trend started with combination oil rings and has now expanded to include compression rings.

Currently, the common manufacturing method for this steel piston ring is
A strip-like wire rod formed by drawing is prepared in advance, coiled, and then cut to obtain each ring material. Next, tempering is performed, and then the upper and lower surfaces f! Post-processing such as FWJ, cutting of the inner and outer circumferences, smoothing of the joints, wear-resistant surface treatment, and finishing of the outer circumferential surface are performed to create a finished product.

(Problems to be Solved by the Invention) However, the above-mentioned current method for manufacturing steel piston rings has many problems in the process of producing quality, which is also important in terms of function of the piston ring. That is, since twist occurs when coiling a +11 band-shaped wire, it is necessary to correct f1 in the heat refining process and post-processing.

(2) When coiling a strip-shaped wire rod, the cross section is deformed (the outer circumferential side becomes thinner and the inner circumferential side becomes thicker).
It will be necessary to make corrections in post-processing.

(3) Since twisting occurs when coiling a strip-shaped wire, it is difficult to get a ring with the same shape because it does not come into complete contact with the coiling jig.

The present invention has been made in view of the above points, and provides a method for manufacturing a steel piston ring that solves the above problems, is easy to manufacture, and can obtain a steel piston ring with excellent precision and quality. The purpose is to provide

(Means for Solving the Problems) The structure of the present invention for achieving the above object includes a step of coiling a steel wire rod having a circular cross section, a step of cutting the coiling wire rod to obtain a ring material, A step of pressing the ring material to give the ring material a desired cross-sectional shape, a step of refining the ring material after the press working, and a post-processing of the ring material after the annealing. It consists of a process.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

(11 wire (see Figures 3 and 4) JISG4309 stainless steel wire 1 (SOS42
0J2, wire diameter 2.6mmφ) (2) Coiling (see Figures 5 and 6) The above wire rod 1 is coiled into a perfect circle (inner diameter 71.9mm
Coil to φ).

At this time, since the wire rod 1 is a round wire rod, it can be brought into close contact with the jig 2 to obtain a perfect circular coiling wire rod 3.

(3) Cutting (see Figure 7) Cut the coiling wire 3 using a milling cutter.
Each book of ring material 4a is obtained.

(4) Press (see Figures 1 and 2) The rolling reduction rate, number of presses, etc. are selected as appropriate. In this embodiment, after coating the ring material 4a thinly with graphite powder,
Cold pressed with a die forging press 5 at a pressure of 105 T, 77.8φ×1゜6 (B) X3.3 (T)
A ring material 4b of mm was obtained.

This pressing process corrects cross-sectional deformation during coiling, haggle h (deviation in dimension B caused in the ring material due to coiling, see FIG. 8), etc. that occurs during coiling.

Further, the cross-sectional shape can be any suitable shape such as a barrel shape.

(5) Heat refining (see Figure 9) Heat refining includes self-tensioning properties in the case of perfectly circular ring products. Quenching is preferably 980 to 1040°C, and tempering is preferably 150 to 650°C. In this example, quenching was performed at 980°C and tempering was performed at 650°C. At this time, distance 6 was set at the abutment part to make the free abutment gap 7.5 mm.

(6) Post-processing Perform normal final processing for piston rings.

Namely, shape processing such as chamfering, edge adjustment, wear resistance treatment (
Chrome plating, thermal spraying, nitriding, par-rising, etc.), outer surface finishing (grinding, turning, lapping, etc.).

In this example, the upper and lower surfaces were polished, the inner and outer peripheries were cut, the joints were smoothed, and the outer periphery was plated with hard chrome. Complete dimensions as a compression ring are 77.5φX1.5 (B)
X3.0 (T) ta, and the surface pressure was 1.69 kg/c&.

In the above embodiments, the case of a perfectly circular ring was explained, but in the case of an elliptical ring, a notch with a size corresponding to the free abutment gap is made in the cutting process, and self-tensioning is not performed in the tempering process.

(Effects of the Invention) As explained above, according to the present invention, since a steel wire rod having a circular cross section is coiled, torsional deformation does not occur during coiling, and therefore, modification of the ring material in post-processing as in the conventional method is not required. becomes unnecessary. Further, since a steel wire rod having a circular cross section is coiled, the steel wire rod is brought into close contact with the coiling jig during coiling, so that an ideal perfect circular or elliptical shape can be obtained. Furthermore, although the cross section of the steel wire is deformed during coiling, it is corrected during the pressing process, so there is no need to correct the ring material in post-processing as in the past. Furthermore, in the press process, for example, piston rings with a curved cross-sectional shape, polygonal piston rings (for example, undercaustic piston rings, etc.), and piston rings with partially different cross-sectional shapes around the entire circumference. Rings with various cross-sectional shapes (for example, inscribed shapes) can be easily obtained with excellent accuracy and quality. The size of the ring can also be adequately adjusted by adjusting the diameter of the steel wire.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the pressing process, Figure 2 is a perspective view of the ring material manufactured in the pressing process, Figure 3 is a perspective view of the wire, Figure 4 is a sectional view of the wire, and Figure 5 is a perspective view of the ring material manufactured in the pressing process. FIG. 6 is a perspective view showing the coiled wire rod, FIG. 7 is a plan view showing the ring material obtained by cutting the coiling wire rod, and FIG. 8 is the ring material produced by coiling. FIG. 9 is a perspective view showing a stack of ring materials in a heat refining process. 1... Steel wire rod 3... Coiling wire rod 4a,
4b...Ring material 5...Press agent Patent attorney Ken Okabe - Figure 1 Figure 4 Figure 6 Figure 8 Figure 9

Claims (1)

[Claims] a step of coiling a steel wire with a circular cross section, a step of cutting the coiling wire to obtain a ring material, a step of applying a press to the ring material to give the ring material a desired cross-sectional shape, and the pressing. A method for manufacturing a steel piston ring, which comprises the steps of: heat-refining a processed ring material; and post-processing the heat-refined ring material.