JPH08257895A - Lap structure for lapping tool - Google Patents

Abstract

PURPOSE: To provide a lap structure for a lapping tool excellent in wearing resistance to long maintain a lap shape and to eliminate necessity for correction work. CONSTITUTION: In a wet lapping tool of applying lapping to a surface of a workpiece through an abrasive grain to finish the surface of the workpiece, a particle holding layer 11, in which a particle holding material 12 softer than the abrasive grain 14 holds a hard particle 13 buried in an almost uniform dispersed condition, is formed in a lap surface, to polish a surface of the particle holding layer 11, and a flat surface of the hard particle 13 polished together is exposed, to hold the abrasive grain in a surface of the particle holding material 12 mutually between the exposed hard particles 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet lapping tool for lapping a work surface through abrasive grains, and more particularly to a lapping structure.

[0002]

2. Description of the Related Art Wet lapping tools perform surface processing by interposing a mixture of abrasive grains and lapping liquid between a workpiece and a lap. Conventionally, the abrasive grains have a moderate hardness like cast iron. It had a wrap structure that digs into the surface of itself and holds it.

[0003]

However, since the holding material such as cast iron that holds the abrasive grains is a softer material than the abrasive grains, the holding material itself wears due to lapping and cannot maintain a predetermined shape. If surface accuracy is required, it is necessary to modify the tool as needed to perform modification. Therefore, the cost is high when performing a special shape of lapping, which requires a high cost for the correction process.

[0004] The present invention has been made in view of such a point,
The purpose thereof is to provide a lap structure of a lapping tool which is excellent in abrasion resistance, has a long lap shape, and does not require correction.

[0005]

In order to achieve the above object, the present invention provides a wet lapping tool for lapping a surface of a workpiece through the abrasive grains to finish the surface of the workpiece. A soft particle-holding material also forms a particle-holding layer in which hard particles are embedded and held in a substantially uniform dispersed state on the lap surface, and the surface of the particle-holding layer is polished and the flat surface of the hard particles is ground together. It is a wrap structure of a lapping tool in which abrasive grains are held between the exposed hard particles and on the surface of a particle holding material between the exposed hard particles.

Since the flat surface of the hard particles embedded in a dispersed manner is scattered and exposed on the surface of the particle holding layer, the abrasive particles wear away the particle holding materials other than the hard particles in the initial stage to form a space between the hard particles. A concave portion is formed, and the abrasive grain enters the concave portion and bites into and is held by the particle holding material. The held abrasive grain laps the surface of the workpiece.

Since the hard particles expose a flat surface on the lap surface, the lap shape is maintained for a long period of time with excellent abrasion resistance. Therefore, even in the processing requiring surface accuracy, it is possible to reduce the cost without the need for the correction processing in which the tool is corrected at any time during the operation.

Nickel is used as the particle holding material and diamond is used as the hard particles, so that the workpiece is made of iron, in particular, the base material of the SUS material is Cr-plated or the SUS material is nitrided. Suitable for other cast iron workpieces.

When the lapping tool is for lapping the surface of a non-circular work piece, it is impossible to perform reciprocal lapping while sequentially rotating a conventional lap. Since it is always maintained, high precision machining can be performed only by reciprocating motion without rotation, and correction machining is not required.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in FIGS. 1 to 4 will be described below. This embodiment is applied to a lapping tool 1 for finishing the outer peripheral surface of a piston ring, and as shown in FIGS. 1 and 2, the inner peripheral surface of an elliptic cylindrical lapping machine 2 forms a lapping surface 3. are doing.

A flat elliptic cylinder-shaped holder 5 is fixed to the lower end of a support shaft 4 which is inserted into the lapping plate 2 from above, and three strips are formed on the outer peripheral surface of the holder 5 in the circumferential direction. Piston rings 6, which are workpieces, are fitted and held in the respective groove shapes. The piston ring 6 is made of wear-resistant cast iron formed in an elliptical annular shape, and the outer peripheral surface of this elliptical shape is lapped. In addition, a SUS base material plated with Cr or a SUS material subjected to a nitriding treatment is suitable as a workpiece.

There is a slight gap between the outer peripheral surface of the holder 5 and the inner peripheral surface of the lapping machine 2, and the piston ring 6 fitted on the outer peripheral surface of the holder 5 is protruded to the outside to provide a predetermined lapping. It is pressed against the inner peripheral surface of the lapping machine 2, that is, the lapping surface 3 by pressure. The holder 5 moves up and down with the central axis aligned with the lapping machine 2 to slide the outer peripheral surface of the piston ring 6 onto the lapping surface 3 for lapping.

The lapping surface 3 of the lapping machine 2 is enlarged and shown in FIG. Particle holding layer 11 on the surface of base material 10 of lapping machine 2
In this embodiment, the particle holding layer 11 is diamond particles in which nickel 12 which is a particle holding material softer than SiC (commonly known as carborundum) 14 which is an abrasive grain is hard particles.
13 are embedded and held in a substantially uniform dispersed state.

The diamond particles 13 are exposed by polishing the surface to a flat plane, the exposed surfaces of the diamond particles 13 are substantially flush with each other, and SiC 14 enters into the worn recesses between the diamond particles 13. It bites into and is held in nickel 12. Here, the diamond particles 13 have a particle size of 150 to 250 μm and an average of about 200 μm, and SiC14 as an abrasive has a particle size of around 30 μm or less, and the particle size of the abrasive is the lapping process step. Select according to.

The process of forming the lap surface 3 having such a structure is shown in FIG. First, as shown in FIG. 4 (1), soft nickel 12 in which diamond particles 13 are substantially uniformly dispersed and mixed is electrodeposited on the surface of a substrate 10 by a generally industrialized method, and the particle holding layer 11 is formed. To form.

Next, as shown in FIG. 4 (2), the surface of the particle holding layer 11 is polished to a particle holding layer 11 having a thickness of about 100 μm.
And By this polishing, the diamond particles 13 are also polished to form a flat surface and are exposed on the surface.
The ratio of the total area of the exposed planes of diamond particles 13 to the total surface area of 11 (diamond density) is about 60 to 80.
Account for%.

The lapping process is started with the surface condition of such a lap. The piston ring 6 fitted and held in the holder 5 is fitted into the cylinder of the lapping machine 2, and the piston ring 6 is reciprocated up and down by interposing a mixture of SiC14 and lapping liquid between the piston ring 6 and the lapping surface 3. When moving and starting the lapping process, soft nickel 12
Are gradually abraded by the SiC14 to form recesses between the diamond particles 13, and as shown in FIG. 4 (3), the SiC14 enter and are held in the recesses, and at the same time the SiC
14 penetrates into and is retained by nickel 12, which is the bottom of the recess.

Thereafter, the lap surface 3 is maintained in the state shown in FIG. 4C, and the outer peripheral surface of the piston ring 6 is lapped by the SiC 14 which has entered the recess between the diamond particles 13.

Since the flat surface of the diamond particles 13 is exposed on the lap surface 3, it is excellent in abrasion resistance and the lap shape is maintained for a long period of time. Therefore, it is not necessary to perform further correction processing after finishing the outer peripheral surface of the piston ring 6, and the productivity can be improved. It is suitable for mass production and can reduce the cost.

By the way, if the machining surface of the workpiece is a circumferential surface, the surface pressure accuracy can be easily maintained by performing the reciprocal lapping while successively rotating the lap as in the conventional case. Piston ring 6 which is a work piece as an example
If it has an elliptical shape or other special shape, it is difficult to perform the reciprocal lapping process involving the rotation of the lap, and it is difficult to maintain the surface pressure accuracy.

That is, when lapping is performed without turning the lap, if there is a locally high lapping surface pressure, a tool with low wear resistance will wear only in that portion in a short time and the shape of the tool will change. It will change, and the processing cost will increase even if it is reprocessed to oversize.

The lapping tool 1 of this embodiment has a lapping surface 3
Since the diamond particles 13 exposed to the inside maintain the lap shape and are excellent in abrasion resistance, the surface processing of the non-circular work piece as described above can be accurately performed only by the reciprocating movement of the lap. When the piston ring 6 of the present embodiment has an elliptical shape, the entire elliptical shape is lapped at once as in the lapping tool 1 of the present embodiment to shorten the processing time and improve productivity. Can be raised.

[0023]

Industrial Applicability According to the present invention, since hard particles expose a flat surface on the lap surface, abrasion resistance is excellent and the lap shape is maintained for a long period of time. However, it is not necessary to perform the correction process, and the cost can be reduced.

By using nickel for the particle holding material and diamond for the hard particles, a workpiece made of iron, in particular, a base material of SUS material plated with Cr or a SUS material subjected to nitriding treatment Suitable for other cast iron workpieces.

When the lapping tool is for lapping the surface of a non-circular work piece, the lap shape is always maintained by the hard particles, so that high precision machining can be performed by sliding other than rotation, and correction machining is also possible. do not need.

[Brief description of drawings]

FIG. 1 is a top view of a lapping tool according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the same.

FIG. 3 is an enlarged cross-sectional view showing the structure of the lap surface of the same example.

FIG. 4 is an enlarged cross-sectional view of the lap surface showing a process of forming the same lap surface structure.

[Explanation of symbols]

1 ... Lapping tool, 2 ... Lapping machine, 3 ... Lapping surface, 4 ...
Support shaft, 5 ... Holder, 6 ... Piston ring, 10 ... Base material,
11 ... Particle holding layer, 12 ... Nickel, 13 ... Diamond particles, 14 ... SiC.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Onimaru 1-4-1 Chuo, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute

Claims (3)

[Claims] 1. A wet lapping tool for finishing a workpiece surface by lapping the surface of the workpiece through abrasive grains, wherein a particle holding material softer than the abrasive grains holds hard particles embedded in a substantially uniform dispersed state. Formed a particle holding layer on the lap surface, the surface of the particle holding layer is polished to expose the flat surface of the hard particles polished together, and the surface of the particle holding material is abraded between the exposed hard particles. Lapping structure of lapping tool characterized by holding grains. 2. The lapping structure for a lapping tool according to claim 1, wherein nickel is used for the particle holding material and diamond is used for the hard particles. 3. The lapping structure for a lapping tool according to claim 1, wherein the lapping tool is for lapping a surface of a non-circular work piece.