JP2884048B2 - Honing whetstone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a honing stone. More specifically, the present invention relates to a honing grindstone for plateau processing that can perform plateau processing of a cylinder liner in one step in a short time.

[0002]

2. Description of the Prior Art Periodic repairs are made to internal combustion engines of ships and generators. A cylinder liner of an internal combustion engine wears unevenly due to its use, and its inner surface has no irregularities and becomes a mirror surface. If the cylinder liner wears unevenly, the airtightness with the piston ring decreases, and blow-by occurs,
The risk of the piston ring scratching the cylinder liner surface increases. In addition, if the inner surface of the cylinder liner becomes a mirror surface, the oil retention will deteriorate, the corrosion and friction and wear rates will increase, and the effect of the oil ring slipping over the oil film surface to scrape off unnecessary oil will decrease, and the consumption of lubricating oil will decrease. Increase. For this reason, the internal combustion engine periodically pulls out the piston, uses a honing machine to remove the uneven wear of the cylinder liner, corrects it close to a perfect circle, and makes the inner surface of the cylinder liner uneven to provide an oil retaining effect. Processing must be performed. FIG. 1 is an explanatory diagram of the plateau processing. In plateau processing,
As shown in FIG. 1 (b), the surface of the cylinder liner which has been mirror-finished as shown in FIG. 1 (a) is made relatively rough as shown in FIG. 1 (b) using a roughening grindstone.
As shown in (c), an operation of shaving the tip of a rough convex portion to provide fine irregularities is performed. According to this working method,
Not only takes a long time for machining, especially roughing, but also requires two types of tools, a roughing grinding wheel and a finishing grinding wheel, and it is necessary to change the tool of the honing machine during the work . In addition, a dress of a grindstone is required for each process, and it is necessary to judge the sharpness of the worker. For this reason, there is a need for the development of a tool that can perform plateau processing in one process in a short time without requiring special skills.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a honing stone capable of performing plateau processing of a cylinder liner of an internal combustion engine in one process in a short time by one kind of tool. It is.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have fixed the abrasive layer layer on which the superabrasive particles are fixed and the WA or GC abrasive particles. It has been found that a honing grindstone having an integrated abrasive grain layer portion can perform plateau processing in one step, and based on this finding, completed the present invention. That is, the present invention has an abrasive grain layer portion having superabrasive grains fixed thereto in front with respect to the rotation direction of the honing head, and having an abrasive grain layer portion having WA abrasive grains or GC abrasive grains fixed thereto at the rear. A honing grindstone for plateau processing characterized by the following. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 is a cross-sectional view of one embodiment of the honing stone of the present invention. In FIG. 2, an abrasive grain layer 1 to which superabrasive grains are fixed and an abrasive grain layer 2 to which WA abrasive grains or GC abrasive grains are fixed are joined and fitted to a grindstone table 3. When the honing grindstone of FIG. 2 is attached to the honing head, the honing grindstone moves in the direction of the arrow in the figure, and after the abrasive layer layer on which the superabrasive grains are fixed comes into contact with the inner surface of the cylinder liner, then the WA abrasive grains Alternatively, the abrasive grain layer portion on which the GC abrasive grains are fixed contacts the inner surface of the cylinder liner.

[0005] In the honing stone of the present invention, diamond abrasive grains or CBN abrasive grains are used as super abrasive grains.
There are no particular restrictions on the particle size of the superabrasives used, but JIS
In the standard of B 4130, the particle size is preferably 30 to 200, and more preferably 60 to 120. In the present invention, the method for fixing the superabrasive grains is not particularly limited, and includes a metal bond, a vitrified bond,
It can be fixed by electrodeposition, resin bond, etc. Among them, metal bond, vitrified bond and electrodeposition can be suitably used. In the honing stone of the present invention, WA abrasive grains or GC abrasive grains are used. The particle size of the WA abrasive grains or the GC abrasive grains to be used is not particularly limited, but is preferably from 36 to 220, more preferably from 60 to 120 according to JIS R 6001. In the present invention, there is no particular limitation on the method for fixing the WA abrasive grains or the GC abrasive grains, and the metal grains, the vitrified bond, the electrodeposition, the resin bond, and the like can be used. Can be used for In the honing grindstone of the present invention, there is no particular limitation on the method of joining the abrasive layer layer with the superabrasive particles fixed thereto and the abrasive layer with the WA abrasive particles or the GC abrasive particles fixed thereon. Alternatively, when WA abrasive grains or GC abrasive grains are fixed by metal bond or the like, they can be joined by brazing. Abrasive layer with superabrasives fixed and WA
There is no particular limitation on the method of joining the abrasive layer layer to which the abrasive grains or the GC abrasive grains are fixed, and the abrasive grain layer can be joined with an epoxy adhesive or the like. If they are fixed by a bond or the like, they can be joined by brazing.

[0006] The shape of the honing grindstone of the present invention is not particularly limited. For example, one long honing grindstone can be joined to the grindstone base, or a plurality of short honing grindstones can be formed with a gap therebetween. Can be joined. FIG. 3 is a side view of one embodiment of the honing stone of the present invention. In this figure, three short honing stones 4
Are joined to the grindstone table 3 with a gap. It is preferable that a gap is formed by using a short honing stone because the flow of the coolant and the discharge of the chips become easy, and the plateau processing can be performed efficiently. When performing plateau processing using the honing grindstone of the present invention, a grindstone base to which the honing grindstone of the present invention is joined is attached to the arm of the honing head. The honing grindstone is mounted such that the abrasive layer layer with the superabrasives attached thereto is forward and the abrasive layer with the WA abrasive grains or the GC abrasives attached thereto is backward with respect to the rotation direction of the honing head. The honing head having four honing arms is preferable for correcting uneven wear of the cylinder liner. The honing head is inserted into the cylinder, the honing grindstone is brought into contact with the inner surface of the cylinder liner, and the pressure of the honing grindstone corresponding to the inner surface of the cylinder liner is adjusted by a pressing device using a spring, hydraulic pressure, air pressure, or the like provided on the honing arm. Then, while flowing the coolant over the inner surface of the cylinder liner, the honing head was rotated and moved up and down,
Perform plateau processing on the inner surface of the cylinder liner. The progress of the plateau processing can be determined by visually observing the inner surface of the cylinder liner. After finishing the plateau processing, retract the honing arm,
Pull out the honing head from the cylinder. After the plateau processing is completed, the state of the plateau processing can be confirmed by measuring the unevenness of the inner surface of the cylinder liner with a surface roughness meter. In order to impart sufficient oil retention in the cylinder liner inner surface is preferably unevenness of R _a cylinder liner surface is 2-6 [mu] m, 3
More preferably, it is 5 μm. It is preferable that irregularity of R _max of the cylinder liner surface is 20 to 60 [mu] m, and more preferably 30 to 50 [mu] m. In the conventional plateau processing using a roughing grindstone and a finishing grindstone, for example, plateau processing of one cylinder liner having an inner diameter of 350 mm and a length of about 700 mm required about 30 to 60 minutes. When the honing stone of the present invention is used, the time required for plateau processing of one cylinder liner of the same size is reduced to 3 to 5 minutes.

[0007]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 Width 6 mm, length 75 mm, thickness in the rotating direction 1.5 m, prepared by metal bonding using diamond abrasive grains with a grain size of 35
The abrasive grain layer of m and the abrasive grain layer of width 6 mm, length 75 mm, and thickness 3.5 mm in the rotational direction formed by resin bonding using GC abrasive grains with a grain size of 100 are joined with an epoxy-based adhesive, A honing stone having the shape shown in FIG. 2 was produced. further,
The three honing stones are inserted into the shape shown in FIG.
It was joined to the grindstone stand with an epoxy adhesive at a distance of mm.
Four honing wheels with the same honing grindstone were prepared and attached to the four honing arms of the honing head. Using this honing head, plateau processing was performed on the inner surface of the cylinder liner. The cylinder has an inner diameter of 3
50mm, 700mm long diesel engine cylinder,
Passed two years from the plateau processing previous cylinder liner surface is nearly mirror state, surface roughness meter [Tokyo Seimitsu Co., Ltd., E-30A-type] is R _a of the surface was measured at 0.
58 μm and R _max were 9.36 μm. Insert the honing head into the cylinder and apply a pressure of 7kg / cm ²
Then, the honing stone was pressed against the inner surface of the cylinder liner, the honing head was rotated at a rotation speed of 25 rpm, and a vertical stroke was performed five times in three minutes. The contact surface became 75% in one minute from the start of the rotation of the honing head, and became almost 100% in two minutes. In 3 minutes, the plateau processing was completed. R _a cylinder liner surface after processing
Was 4.46 μm and R _max was 39.76 μm. FIG. 4A is a graph showing the surface roughness of the cylinder liner before processing, and FIG. 4B is a graph showing the surface roughness after processing.

[0008]

According to the honing grindstone of the present invention, the plateau processing of the cylinder liner can be performed in one process in a short time by using only one kind of grindstone without changing the tool.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of plateau processing.

FIG. 2 is a cross-sectional view of one embodiment of the honing stone of the present invention.

FIG. 3 is a side view of one embodiment of the honing stone of the present invention.

FIG. 4 is a graph showing the surface roughness of a cylinder liner before and after processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Abrasive grain layer part to which superabrasive grains were fixed 2 Abrasive grain layer part to which WA abrasive grains or GC abrasive grains were fixed 3 Grindstone table 4 Honing grindstone

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B24B 33/02 B24B 33/08

Claims (1)

(57) [Claims] An abrasive grain layer portion having superabrasive grains fixed thereto in front of a honing head rotating direction and an abrasive grain layer portion having WA abrasive grains or GC abrasive grains fixed thereto are provided rearward. A characteristic honing stone for plateau processing.