JP2962101B2 - Honing method of bore - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for honing a bore used in honing a bore provided in a work such as a cylinder bore of an engine.

[0002]

2. Description of the Related Art As described above, for example, when honing a cylinder bore of an engine, the weight of the cylinder block has recently been reduced and the thickness of the cylinder bore portion has become thin and non-uniform. The generated heat tends to cause non-uniform deformation, and it is becoming difficult to improve the accuracy of roundness and cylindricity.

Therefore, a technique for actively cooling the machined surface of the cylinder bore has been developed and employed, and a honing method for actively cooling such as shown in FIG. As shown in FIG.
A coolant flow path 53 is provided inside a horn 51 having an annular arrangement of the coolant 2, and the coolant flow path 53 is opened between the grindstones 52, and the coolant discharged from a coolant discharge unit 60 located above the cylinder bore Bo. Co
Not only from the coolant channel 53 but also from the coolant channel 53.
A technique of honing while supplying and cooling is known.

[0004] Regarding such a honing method, see, for example, "Automotive Technology Handbook Production / Quality / Maintenance Edition".
June 15, 1992 Edited by the Society of Automotive Engineers of Japan
There is some description on page 198 of the publication.

[0005]

However, in the honing method described above, although the coolant Co can be supplied to the processing surface of the cylinder bore Bo, the cylinder bore Bo is cooled to a uniform degree in the circumferential direction. Therefore, when the heat capacity difference of the cylinder bore Bo in the circumferential direction such as the cylinder block having the siamese structure is large, a temperature difference occurs in the cylinder bore Bo being machined in some places, so that the roundness and the cylindricity with high accuracy are obtained. However, there is a problem that it cannot be said that it is sufficient to obtain the above, and it has been a conventional problem to solve this problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is capable of improving the accuracy of both roundness and cylindricity, as well as extending the life of a grindstone. The aim is to provide a bore honing method that can.

[0007]

SUMMARY OF THE INVENTION A method of honing a bore according to the present invention is a method of honing a bore provided in a workpiece by a horn having a plurality of grindstones arranged in an annular shape. A coolant nozzle is provided on the opposite side of the horn, and a cutout is provided between the grinding wheels in the axial direction and at the tip of the horn, and coolant is injected from the coolant nozzle toward a portion having the smallest heat capacity in the bore. The above-described configuration of the honing method for a bore is a means for solving the above-described conventional problem.

[0008]

In the method for honing a bore according to the present invention, the coolant injected from the coolant nozzle is:
The notch in the horn directly hits the inner surface of the bore, and since this portion is the part with the lowest heat capacity on the inner surface of the bore, even if the heat capacity difference of the bore in the circumferential direction is large, There is almost no temperature difference in the bore of the hole, so that the accuracy of the roundness and the cylindricity are respectively improved.

In addition, the life of the grindstone is prolonged because the supply condition of the coolant is improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show one embodiment of a method for honing a bore according to the present invention. In this embodiment, a case where a cylinder bore of an engine is honed is shown.

The horn 1 shown in the figure has a substantially cylindrical shape, and has six grindstones 2 arranged on the outer peripheral surface thereof at an interval of 60 °.
Grindstone holder 3 slidable between the hollow part and the outside
Is attached to each. The horn 1 is configured to connect a small-diameter cylindrical portion 1a formed on the base end side (upper end side in FIG. 1) to a support shaft (not shown) of a honing machine. The rotational force is transmitted via a pin 4 provided on the rim.

The horn 1 has a conical surface 5 in its hollow part.
The distal-side pressing body 5 having a is accommodated, and the distal-side pressing body 5 is connected via a pressure-receiving plate 7 to the distal end of a rod 6 inserted through the small-diameter cylindrical portion 1a. In this hollow portion, a proximal pressing body 8 having the same conical surface 8a located above the distal pressing body 5 is housed, and the proximal pressing body 8 is located near the lower end of the rod 6. It is fitted.

A downward pressing force shown in FIG. 1 is applied to these pressing members 5 and 8 from an extruding compression coil spring 9 which is fitted above the base-side pressing member 8 and accommodated in the rod 6. The pressure receiving slopes 3 provided with the conical surfaces 5a, 8a of these pressing bodies 5, 8 on the hollow part side of the grinding wheel holder 3 and vertically.
a and 3a, respectively.
The grindstone 2 is extruded in the radial direction with a downward pressing force.

A compression coil spring 11 penetrating through the center of the distal end pressing body 5 is provided between the spring receiver 10 for closing the hollow portion and the pressure receiving plate 7, so that the upward force shown in FIG. Extrusion compression coil spring 9 applied to bodies 5 and 8
The pressing force applied to the grindstone 2 is kept constant.

Further, the horn 1 is provided with a plurality of notches 12 which are open in the outer peripheral surface in the axial direction and at the tip (the lower end in FIG. 1), and these notches 12 are provided between the six grinding stones 2. It is.

On the other hand, on the bed 20 on which the cylinder block S is mounted, that is, on the side opposite to the side where the horn 1 of the cylinder bore B is inserted, in this embodiment, two coolant nozzles 21 are provided. , Between the cylinder block S and the horn 1, the coolant discharge ports 22a,
A horn guide 22 having an inner peripheral surface 22a is provided, and the coolant nozzles 21 and 21 of the bed 20 are installed so that the coolant C can be injected into a portion of the cylinder block S where the heat capacity is the smallest in the cylinder bore B. is there.

When honing the cylinder bore B to the cylinder block S on the bed 20 on which the coolant nozzles 21 and 21 are installed by using the horn 1 described above, the horn 1 rotating through the horn guide 22 is used.
Is lowered, and is inserted into the cylinder bore B as shown by a virtual line.

The rotating horn 1 is caused to move up and down while discharging the coolant C from the coolant discharge ports 22a and 22a of the horn guide 22 and ejecting the coolant C upward from the coolant nozzles 21 and 21. The inner surface of the cylinder bore B is machined.

At this time, in addition to the coolant C being supplied from the coolant discharge ports 22a, 22a to the cylinder bore B, the notch 12 is provided in the horn 1, so that the coolant C is injected from the coolant nozzles 21, 21. Since the coolant C directly hits the inner surface of the cylinder bore B, the cylinder bore B is sufficiently cooled.

The portion of the coolant C which is sprayed from the coolant nozzles 21 and 21 hits the cylinder bore B.
Where the heat capacity on the inner surface of the
In the case where machining is performed without injecting the coolant C from the coolant nozzle 21, a portion having a short diameter when an ellipse is formed instead of a perfect circle or a small diameter when a cylinder has an irregular shape such as a truncated cone or a drum shape. Since it is a part, even if the heat capacity difference of the cylinder bore B in the circumferential direction is large, there is almost no temperature difference in the cylinder bore B during processing, so that the accuracy of roundness and cylindricity is improved. It will be.

Further, since the supply amount of the coolant C increases and the supply condition improves, the life of the grindstone 2 is extended.

Then, when the honing method of the cylinder bore B is performed by the above-mentioned honing method, the result that the accuracy of the roundness and the cylindricity is improved more than before, and the life of the grindstone 2 is about 10 % Increase.

In this embodiment, the case where the bore honing method according to the present invention is applied to the honing of a cylinder bore of an engine is exemplified. However, the present invention is not limited to this, and the bore honing method according to the present invention is also applicable. The detailed configuration of the honing method is not limited to the above embodiment.

[0025]

As described above, the method for honing a bore according to the present invention has the above-described structure.
Irrespective of the difference in the characteristics of the work, it is possible to realize both an improvement in the accuracy of the roundness and the accuracy of the cylindricity, and at the same time, a very excellent effect that the life of the grindstone can be extended.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing an embodiment of a method for honing a bore according to the present invention when honing a cylinder bore.

FIG. 2 is an explanatory bottom view of the horn shown in FIG. 1;

FIG. 3 is an explanatory side view showing a conventional method of honing a bore when honing a cylinder bore;

[Explanation of symbols]

 1 Horn 2 Whetstone 12 Notch 21 Coolant nozzle B Cylinder bore (bore) C Coolant S Cylinder block (work)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B24B 33/02 B23Q 11/10 B24B 33/10 B24B 55/02

Claims (1)

(57) [Claims] When honing a bore provided in a workpiece by a horn having a plurality of grindstones arranged annularly, a coolant nozzle is provided on a side of the bore opposite to a side where a horn is inserted, and A honing method for a bore, characterized in that a notch that opens in the axial direction and at the tip of the horn is provided therebetween, and coolant is injected from the coolant nozzle toward a portion having the smallest heat capacity in the bore.