CN115156604A - Piston ring opening milling cutter and opening processing method - Google Patents

Abstract

The application provides a piston ring opening milling cutter, it has at least one row of cutting edges around installation axle circumference range, the cutting face that the cutting edge formed includes radial growth's main cutting face, main cutting face both sides are first shaping surface and second shaping surface respectively, first shaping surface, the second shaping surface all is perpendicular to the installation axle; the cutting surface formed by the cutting edge further includes a first side cut surface extending obliquely from the first forming surface outside the first forming surface and a second side cut surface extending obliquely from the second forming surface outside the second forming surface. The utility model provides a piston ring opening milling cutter replaces original CBN emery wheel finish grinding through using saw bit milling cutter, has reduced the design requirement to slewing mechanism to overcome the problem of processing burr, realized processing when opening clearance and chamfer, thereby realize the optimization promotion of process when promoting the process velocity.

Description

Piston ring opening milling cutter and opening processing method

Technical Field

The invention relates to the technical field of cutting machining, in particular to a piston ring opening milling cutter and an opening machining method.

Background

A typical piston ring has an open configuration that allows the ring to be expanded for installation into a ring groove during installation and then returned to a nearly closed position after installation into the ring groove. For a commonly used piston ring product with a simple opening, the size of the opening gap will affect the sealing performance of the piston ring to the cylinder body. In order to avoid scratching the inner wall by the outer edge of the opening when the piston ring rubs against the inner wall of the cylinder sleeve, the outer edge of the opening of the piston ring is also provided with a chamfer.

In the conventional piston ring machining technology, the opening is usually finished on the basis of a rough piston ring semi-finished product. One way of finishing is to pass the piston ring in the contour cavity to squeeze the piston ring to the desired diameter and finish the sides of the opening with a CBN grinding wheel as the piston ring passes the machining site in the contour cavity. However, the adoption of the accurate grinding mode can generate burrs with the height of more than 0.02mm on the opposite unscrewing side of the CBN grinding wheel of the opening of the piston ring, so that an additional process is needed for removing the burrs; on the other hand, the openings are finely ground by using the CBN grinding wheel, so that the required opening shapes cannot be machined at one time, and subsequent chamfering is required. For example, an invention patent application with the publication number of CN108772757, named as "an automatic machine for chamfering the outer edge of the piston ring opening", of the same applicant discloses a chamfering device for the piston ring opening, which is used for chamfering the piston ring with the opening already ground.

Disclosure of Invention

In view of the problems of edge burrs, incapability of forming chamfers at one time, more additional processes caused by the chamfers and long processing time in the prior art, the application provides a piston ring opening milling cutter and an opening processing method.

The application provides a piston ring opening milling cutter, the piston ring opening milling cutter has at least one row of cutting edges around installation axle circumference range, characterized in that, the cutting face that the cutting edge formed includes radial growth's main cutting face, main cutting face both sides are first shaping surface and second shaping surface respectively, first shaping surface, second shaping surface and the median plane become angle beta and set up; beta is in the range of 5-10 degrees;

the cutting surface formed by the cutting edge further includes a first flank surface extending obliquely from the first molding surface 1A2 outside the first molding surface and a second flank surface extending obliquely from the second molding surface outside the second molding surface.

Specifically, the piston ring opening milling cutter comprises a first chamfering saw blade, a middle cutting saw blade and a second chamfering saw blade which are sequentially attached along an installation shaft;

the intermediate cutting saw blade has a circumferential array of gullet teeth for forming the primary cutting face, the first forming face and the second forming face;

the first chamfering saw blade is provided with first cutting teeth which are arranged in the circumferential direction and are used for forming the first side section;

the second chamfer saw blade is provided with a second cutting tooth which is arranged circumferentially and is used for forming the second side section.

Specifically, the rake angle γ of each of the first cutting tooth and the second cutting tooth is in the range of 5 to 10 °, and the relief angle α of each of the first cutting tooth and the second cutting tooth is in the range of 8 to 18 °.

Specifically, the radius of the cutting edge of the piston ring opening milling cutter is 40mm. The number of teeth is between 100 and 200.

Specifically, a piston ring is grooved by using a piston ring slotting cutter according to any one of claims 1 to 4, the rotation speed of the piston ring slotting cutter is 200 to 600RPM, the piston ring passes through a milling position along the tangential direction of the piston ring slotting cutter, and the feeding speed of the piston ring W is 10 to 20cm/min.

The application provides a piston ring opening milling cutter replaces original CBN emery wheel finish grinding process through using saw bit milling cutter, can reduce the 3000RPM of original use CBN emery wheel to below the 600RPM that uses milling cutter, consequently lower to slewing mechanism's designing requirement, is favorable to improving slewing mechanism's life and energy saving. Meanwhile, through reasonable design of process parameters and cutter parameters, the problem of burrs of the original fine grinding process can be solved, and an additional deburring process is omitted. The piston ring opening milling cutter realizes simultaneous processing of the opening of the piston ring and the outer edge of the opening through the cutting surface matched with the shape design of the opening of the piston ring, so that an additional chamfering process can be omitted. And the saw blade milling cutter has lower processing resistance and sharper cutting edge compared with the CBN grinding wheel, so that the material feeding speed of the piston ring can be increased to 10-20 cm/min from 5-15 cm/min when the fine grinding process is used. Thereby the production takt time of a single procedure can be improved by nearly 50 percent.

Drawings

Fig. 1 is a schematic view of a cutting face of a saw blade milling cutter 1 of the present application;

FIG. 2 is a schematic view of the arrangement of the slotting teeth 12A of the present application;

FIG. 3 is an enlarged partial view of the slotted tooth 12A;

FIG. 4 is a schematic view of the notched tooth 12A taken along the direction B-B;

fig. 5 is a schematic view of the machining of the saw blade milling cutter 1 of the present application;

fig. 6 is an operation diagram of the piston ring opening processing method of the present application.

1, a saw blade milling cutter 11, a first chamfer saw blade 12, a middle cutting saw blade 13, a second chamfer saw blade 1A, a cutting edge 1A1, a main cutting surface 1A2, a first molding surface 1A3, a second molding surface 1A4, a first side cutting surface 1A5, a second side cutting surface S, a middle surface O, a mounting shaft 12A, a grooving tooth 11A, a first cutting tooth 13A, a second cutting tooth W, a piston ring FW, a windward surface BW, a leeward surface P, a cutting edge R, a rotating direction 12AA, a first tooth 12AB, a second tooth G, a piston ring channel N, a piston ring feeding direction

Detailed Description

The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, in this specification, the dimensional ratios of the drawings do not represent actual dimensional ratios, and are only used for embodying the relative positional relationships and the connection relationships between the components, and the components having the same names or the same reference numbers represent similar or identical structures and are only used for illustrative purposes.

The application provides a piston ring opening milling cutter mainly used solves the high-efficient automated processing problem to piston ring W's opening clearance. The piston ring opening milling cutter uses the saw blade milling cutter 1 to cut and process the piston ring W so as to obtain the piston ring W with the opening size meeting the quality requirement. As shown in fig. 1, the saw blade 1 is mounted around a mounting shaft O, and a cutting edge 1A for cutting a piston ring W is provided in a circumferential direction of the saw blade 1. The definition of the cutting surface of the cutting edge 1A is the envelope surface formed after one complete revolution of the cutting edge 1A, and it can also be considered that the blade milling cutter 1 will cut a cutting edge in line with the cutting surface when it rotates.

Specifically, the cutting surface of the cutting edge 1A of the present application is adapted to the opening shape of the piston ring W, the cutting surface formed by the cutting edge 1A includes a radially-grown main cutting surface 1A1, the two sides of the main cutting surface 1A1 are respectively a first molding surface 1A2 and a second molding surface 1A3, the first molding surface 1A2 and the second molding surface 1A3 are disposed at an angle β with a symmetrical middle plane S of the cutting edge 1A, β is in a range of 5 to 10 °, so that the width of the main cutting surface (1A 1) is slightly larger than other positions of the middle cutting saw blade 12, when the middle cutting saw blade 12 is fed, the cut opening is determined by the width of the main cutting surface 1A1, and the other positions of the middle cutting saw blade 12 are slightly smaller than the main cutting surface 1A1 and therefore cannot contact with the machined surface of the piston ring W, thereby avoiding the formation due to friction between the first molding surface 1A2, the second molding surface 1A3 and the machined surface of the piston ring W; the value of beta should not be too large so as to avoid affecting the performance of the main cutting surface 1A1 and prevent the main cutting surface 1A1 from frequently breaking teeth. The main cutting surface 1A1 is a main cutting surface for cutting an opening of the piston ring W, and the first molding surface 1A2 and the second molding surface 1A3 are respectively used for molding a side edge of the opening of the piston ring W, so that the first molding surface 1A2 and the second molding surface 1A3 are perpendicular to the mounting shaft O, and when the saw blade milling cutter 1 processes the piston ring W, the side edge of the opening gap of the piston ring W molded by the first molding surface 1A2 and the second molding surface 1A3 can be ensured to be perpendicular to the piston ring.

The opening of the piston ring W needs to be chamfered in order to avoid scratching the inner wall of the cylinder liner during operation, and for this purpose, a first side cut surface 1A4 extending obliquely from the first molding surface 1A2 is provided on the side of the first molding surface 1A2, and a second side cut surface 1A5 extending obliquely from the second molding surface 1A3 is provided on the side of the second molding surface 1 A3. The first side cut surface 1A4 and the second side cut surface 1A5 are used for forming chamfers on both sides of the outer edge of the opening gap of the piston ring W, respectively, and thus the angles thereof are set corresponding to the chamfer angles of the piston ring W, accordingly, since negative chamfers are not possible, it is obvious to those skilled in the art that the inclination directions of the first side cut surface 1A4 and the second side cut surface 1A5 should be inclined to extend from the first forming surface 1A2 to the direction of the mounting shaft O, and the second forming surface 1A3 should be inclined to extend from the second forming surface 1A3 to the direction of the mounting shaft O. I.e. the orientation shown in fig. 1. The angle of which is determined as required.

The present application provides a specific embodiment of a blade milling cutter 1 formed by combining a plurality of blade milling cutters, specifically, the blade milling cutter 1 includes a first chamfer saw blade 11, a middle cutting saw blade 12 and a second chamfer saw blade 13, which are arranged along a mounting shaft O in an abutting manner in sequence; the first 11, intermediate 12 and second 13 chamfering blades may form a rotating whole in a reasonably fixed arrangement. Wherein the middle cutting saw blade 12 is provided with circumferentially arranged slotting teeth 12A, and the slotting teeth 12A are used for forming a main cutting surface 1A1, a first molding surface 1A2 and a second molding surface 1A3; that is, the opening gap of the piston ring W will be accurately cut out at the cutting of the intermediate cutting saw blade 12, and the opening gap is substantially equal in size to the distance between the first molding surface 1A2 and the second molding surface 1A3, regardless of the cutting error. Since the end face of the piston ring W enters the cutting area perpendicular to the tangential direction of the saw blade cutter 1 during cutting, the opening direction of the piston ring W perpendicular to the end face of the piston ring W is ensured without inclination by the parallel first and second molding surfaces 1A2 and 1 A3.

In particular, no special requirements are imposed on the tooth shape of the intermediate cutting blade 12, and tool steel or other alloy steel, which is generally used for cutting metal, and tooth portions, may be acceptably hardened by using ceramic materials or other high hardness materials. Fig. 2 is a side view of the intermediate cutting blade 12 of the present application in the direction of the mounting axis O, and shows the distribution of the gullet teeth 12A of the intermediate cutting blade 12. The arrangement of the slotted teeth 12A will now be described in detail with a close-up view at a in the slotted teeth 12A (i.e., fig. 3). The grooving teeth 12A are arranged along the edge circumference of the middle cutting saw blade 12, the cutting edges P of the grooving teeth 12A are all arranged along the same circumferential direction, and when the grooving teeth 12A cut the piston ring W along the direction of the rotation direction R, the cutting edges of the grooving teeth 12A will form a positive cutting effect on the surface of the piston ring W in contact, so as to realize cutting grooving. The leeward surface BW faces away from the uncut surface and is recessed to form a cavity for receiving swarf generated by cutting.

The side cross-section of the grooved teeth 12A is the same as that in fig. 3, but it is not always required to have a uniform cross-sectional design in the direction of the mounting axis O so that the cutting edge P is a straight portion parallel to the mounting axis O to cut the piston ring W uniformly. However, in fact, considering that the main cutting surface 1A1 cut and formed by the cutting edge P does not remain on the piston ring W, but penetrates through the inner and outer edges of the piston ring W and is completely cut off by the forming surface acted by the main cutting surface 1A1, the shape of the cutting edge P does not need to be particularly required, so that the present application preferably provides a design scheme of the slotting tooth 12A, which is schematically shown in the direction B-B in fig. 3 as shown in fig. 4. The adjacent slotting teeth 12A are respectively a first tooth 12AA and a second tooth 12AB, and the cutting edges P corresponding to the first tooth 12AA and the second tooth 12AB are alternately arranged obliquely as shown in the figure. Then, in the machining diagram shown in fig. 5 (in the drawing, the gap on both sides of the cutting edge 1A is merely used for convenience, and the gap is not present in the actual cutting process, and b, and the cutting edge 1A is a virtual surface configured for convenience of description, and is not actually present), the piston ring W is fed down the paper surface, and the saw blade mill 1 rotates its cutting teeth upward from the paper surface at the illustrated position where the cutting action with the piston ring W is generated. In the process of cutting the piston ring W by the main cutting surface 1A1, because the tooth form of the grooving teeth 12A is alternately arranged as shown in figure 4, when the piston ring W is not completely cut off, a middle dent as shown in figure 5 is inevitably formed on the surface formed by cutting at the main cutting surface 1A1, and because the dent has a better attenuation effect on the left-right vibration of the saw blade milling cutter 1, because the left-right vibration of the saw blade milling cutter 1 is reduced, the periodic impact of the windward surface FW on the edge of the gap of the piston ring W when the cutting edge 1A enters and exits the gap of the piston ring W is reduced, and the problem of overlarge burrs caused by the periodic impact can be well solved.

For the first and second chamfering blades 11 and 13, the circumferentially arranged first cutting teeth 11A for cutting the outer peripheral surface chamfer forming the piston ring W, i.e., the first chamfering blade 11, are used to cut the piston ring W to form the first side cut surface 1A4 when rotating, and the circumferentially arranged second cutting teeth 13A for the second chamfering blade 13 are used to cut the blade cutter 1 to form the second side cut surface 1A5 when rotating.

In addition, the following experimental data of table 1 were obtained by customizing a saw blade milling cutter for experiments with a saw blade supplier and performing test runs:

therefore, it is preferable that the rake angle γ of each of the first cutting tooth 11A and the second cutting tooth 13A is in the range of 5 to 10 °, and the relief angle α of each of the first cutting tooth 11A and the second cutting tooth 13A is in the range of 8 to 18 °.

The radius of the cutting edge 1A in the application is 40mm, the number of teeth is controlled in the range of 100 to 200 teeth, and the number of teeth in the embodiment of the application is 168 teeth. Fig. 6 is a schematic view of the saw blade mill 1 and the other side surface of the piston ring W according to the present invention, and the step of automatically machining the opening gap of the piston ring W using the saw blade mill 1 will be described with reference to the drawings. Piston ring W self-drawing piston

TABLE 1 trial data of tooth profile effect on burrs

The channel formed by the ring channel G passes through the position of the saw blade milling cutter 1 along the feeding direction N of the piston ring, the saw blade milling cutter 1 is arranged by invading the interior of the piston ring channel G according to the preset position, and the distance in the interior of the piston ring channel G is greater than the height difference of the inner edge and the outer edge of the piston ring W so as to ensure that the opening gap of the piston ring W can be completely processed when the piston ring W passes. The piston ring channel G provides a channel for feeding the piston ring W, and also serves to shape the piston ring W, i.e., to press the piston ring W, which is moderately opened due to elasticity, to an installation dimension in the cylinder liner, so as to prevent a machining dimension error of the opening gap. On the basis, the rotation speed of the saw blade milling cutter 1 is set to be 200-600 RPM, preferably 400RPM, so that the processing surface quality of the opening gap of the piston ring W can be ensured and the generation of processing burrs can be avoided under the condition that the piston ring W passes through the piston ring channel G at the speed of 10-20 cm/min. In the prior art, because the CBN grinding wheel is adopted to process the opening gap of the piston ring W, the friction surface is required to have higher linear velocity to obtain the required grinding effect, the rotating speed of the grinding wheel cannot be lower than 3000RPM, and meanwhile, in order to ensure the grinding time of a single piston ring, the feeding speed of the piston ring can only be controlled to be 5-10 cm/min. The feed rate of the piston ring W actually determines the production rate of the piston ring W, and the tact of the piston ring W can be basically improved by about 50% due to the increase of the feed rate. In addition, in the processing mode of fig. 6, the piston ring W may enter in a single piece or pass through the piston ring channel G in a multi-piece or continuous manner, so that the production efficiency is improved while the automatic processing is realized.

The above description is only for the purpose of describing the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention are intended to fall within the protection scope defined by the claims of the present invention.

Claims (5)

1. A piston ring slotting cutter having at least one row of cutting edges (1A) arranged circumferentially around a mounting axis (O), characterized in that the cutting surfaces formed by the cutting edges (1A) comprise a radially growing main cutting surface (1A 1), on either side of which main cutting surface (1A 1) there is a first (1A 2) and a second (1A 3) profiled surface, respectively, the first (1A 2) and the second (1A 3) profiled surface being arranged at an angle β to the median plane (S); beta is in the range of 5-10 degrees;

the cutting surface formed by the cutting edge (1A) further comprises a first side cutting surface (1A 4) extending obliquely from the first molding surface 1A2 outside the first molding surface (1A 2) and a second side cutting surface (1A 5) extending obliquely from the second molding surface (1A 3) outside the second molding surface (1A 3).

2. The piston ring opening mill as claimed in claim 1, characterized in that it comprises a first chamfer saw blade (11), an intermediate cutting saw blade (12) and a second chamfer saw blade (13) arranged in abutment in succession along the mounting axis (O);

the intermediate cutting saw blade (12) has a circumferential array of grooving teeth (12A), the grooving teeth (12A) being used to form the primary cutting surface (1A 1), the first forming surface (1A 2) and the second forming surface (1A 3);

the first chamfering blade (11) has a circumferential row of first cutting teeth (11A), the first cutting teeth (11A) are used for forming the first side section (1A 4);

the second chamfer saw blade (13) has a second cutting tooth (13A) arranged circumferentially, the second cutting tooth (13A) being used to form the second side cutting surface (1A 5).

3. The piston ring slotting cutter according to claim 2, wherein the rake angle γ of each of the first cutting tooth (11A) and the second cutting tooth (13A) is in the range of 5-10 °, and the relief angle α of each of the first cutting tooth (11A) and the second cutting tooth (13A) is in the range of 8-18 °.

4. Piston ring slotting cutter according to claim 1, wherein the cutting edge (1A) of the piston ring slotting cutter has a radius of 40mm. The number of teeth is between 100 and 200.

5. A piston ring split machining method, characterized in that a piston ring (W) is grooved using the piston ring split milling cutter according to any one of claims 1 to 4, the rotation speed of the piston ring split milling cutter is 200 to 600RPM, the piston ring (W) passes through a milling position in a tangential direction of the piston ring split milling cutter, and the feed speed of the piston ring W is 10 to 20cm/min.

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