JPH03256664A - Honing method for cylinder bore for aluminum cylinder block - Google Patents

Abstract

PURPOSE:To prevent the occurrence of one-side wear of the inner surface of a piston ring and a cylinder bore during running of an assembled engine by applying a honing work as substantially the same axial tension as that in a state to mount a cylinder head is exerted on a screw part for mounting a cylinder head. CONSTITUTION:A honing work is applied as substantially the same axial tension as that in a state to mount a cylinder head is exerted on a screw part 1b for mounting a cylinder head. The honing work is applied on the inner surface of the cylinder bore in a state that the peripheral part of a cylinder bore 1a is microdeformed by the axial tension substantially to the same extent as that in a state to mount the cylinder head and along with the microdeformation, the shape of the inner surface of the cylinder bore is microdeformed. Thereby, by increasing roundness by the honing work, roundness is reproduced even in a state that the cylinder head is mounted on an aluminum cylinder block 1, and during running of an assembled engine, one-sided wear of a piston ring and the inner surface of the cylinder bore is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a honing method suitable for use in honing the inner surface of a cylinder bore of an aluminum alloy cylinder block used in an engine, that is, a so-called aluminum cylinder block. This relates to processing methods.

(Prior Art) When honing the inner surface of the cylinder bore of an aluminum cylinder block, conventionally, as shown in Fig. 3, the lower end of the cylinder block l is fixed on the bed 3 of the honing machine 2, and the cylinder bore is honed. The honing tool 4 is inserted into the bore from the upper end opening of Ia, and the honing tool 4 is rotated and raised.

(Problem to be Solved by the Invention) However, since aluminum cylinder blocks have lower rigidity than cast iron cylinder blocks, it is necessary to reduce the circularity of the inner surface of the cylinder bore by, for example, 5 μm using the conventional honing method described above.
Even if the cylinder head is mounted on the top surface of the cylinder block 1 as shown in FIG. When the head is installed, the peripheral portion of the cylinder bore 1a is slightly deformed due to the axial force acting on the peripheral portion of the screw hole 1b, and the roundness of the inner surface of the cylinder bore is thereby reduced to, for example, about 8 to 20μ. As a result, when the engine is operated, uneven wear occurs on the piston ring and the inner surface of the cylinder bore, and the tightness of the piston ring to the inner surface of the cylinder bore is also impaired, resulting in increased oil consumption. there were.

The present invention provides a honing method that advantageously solves these problems.

(Means for Solving the Problems) The method for honing the cylinder bore of an aluminum cylinder block according to the present invention is based on the condition that the cylinder head is attached to the threaded portion for attaching the cylinder head when honing the inner surface of the cylinder bore of the aluminum cylinder block. The honing process is performed while applying substantially the same axial force.

(Function) According to this method, due to the axial force, the peripheral part of the cylinder bore is slightly deformed to the same extent as the cylinder head is attached, and the shape of the inner surface of the cylinder bore is also slightly deformed accordingly. Since the inner surface of the cylinder bore is honed, if the honing process increases the roundness, that high roundness can be reproduced even when the cylinder head is attached to the aluminum cylinder block. During engine operation, it is possible to prevent uneven wear on the piston ring and the inner surface of the cylinder bore, and to improve the adhesion of the piston ring to the inner surface of the cylinder bore, reducing oil consumption. .

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of the cylinder bore honing method for an aluminum cylinder block of the present invention.
In the figure, 1 is an aluminum cylinder block, 2 is a honing machine,
3 indicates the bed of the honing board 2.

Here, first, the cylinder bore 1a of the cylinder block 1 is
For mounting the cylinder head of the cylinder block 1, a jig 5 having a tool hole 5a with an inner diameter slightly larger than the bore inner diameter and a bolt hole 5b arranged similarly to the screw hole 1b for mounting the cylinder head of the cylinder block 1 is used. , bolts 6 arranged on the upper surface of the cylinder block 1 and inserted into each of its bolt holes 5b.
For each cylinder head installation of the cylinder block L, screw them into the screw holes 1b, tighten the bolts 6 with the same tightening torque as when installing the cylinder head, for example, using a torque wrench, and then attach the jig 5 to the cylinder block 1. adheres to the top surface of the

In this state, substantially the same axial force as when the cylinder head is installed is applied to the peripheral portion of the screw hole 1b for each cylinder head installation, and therefore the cylinder bore 1a
The peripheral part of the cylinder is slightly deformed to the same extent as the cylinder head is attached, and as a result, the cylinder bore 1a
The shape of the inner surface of the jig 5 is also slightly deformed, and the lower end of the fixed cylinder block 1 of the jig 5 is here fixed on the bed 3 of the honing machine 2 and inserted into the tool hole a of the jig 5. Insert the honing tool 4 through the cylinder bore la from the upper end opening into the bore, and rotate and raise and lower the honing tool 4 to open the cylinder bore la.
The inner surface is honed to achieve high roundness.

After the honing process is completed, the bolts 6 are loosened, the jig 5 is removed from the cylinder block 1, and the cylinder block 1 is used for engine assembly.

According to this method, with the cylinder head attached to the aluminum cylinder block 1, the shape of the inner surface of the cylinder bore 1a is slightly deformed again to the same shape as that during the honing process described above, thereby reproducing the high roundness during the honing process. Therefore, when the assembled engine is operated, it is possible to prevent uneven wear of the piston ring and the inner surface of the cylinder bore 1a, and also to improve the adhesion of the piston ring to the inner surface of the cylinder bore 1a, thereby improving the oil flow. Consumption can be reduced.

FIG. 2 is an explanatory diagram showing another embodiment of the cylinder bore honing method for an aluminum cylinder block according to the present invention, in which the same parts as shown in FIG. 1 are designated by the same reference numerals.

In this embodiment, the cylinder bore 1 of the cylinder block 1 is
A tool hole 7a with an inner diameter slightly larger than the inner diameter of the bore, which is arranged similarly to a, and a tool hole 7a, which is arranged similarly to the cylinder head mounting screw hole 1b of the cylinder block 1, and which has the same shape as the threaded part of the bolt. An axial force applying device 7 having a screw shaft 7b and a drive mechanism (not shown) having a structure similar to a DC nut runner capable of rotationally driving each of the male screw shafts 7b with a predetermined torque, and the axial force applying device 7 are mounted on a bed. A lifting device 8 that raises and lowers the cylinder block above 3,
Provided on the honing machine 2.

However, here, after fixing the lower end of the cylinder block 1 to a predetermined position on the bed 3 of the honing machine 2, first, the axial force applying device 7 is lowered to the cylinder block l on the bed 3 by the lifting device 8. While rotating, the male threaded shaft 7b is rotated in the screwing direction by the drive mechanism of the axial force applying device 7, and the male threaded shaft 7b is screwed into each cylinder head mounting screw hole 1b of the cylinder block.
Tighten these male threaded shafts 7b with the same tightening torque as when installing the cylinder head, and then tighten the axial force adding device 7b.
is fixed on the top surface of the cylinder block l.

Next, the honing tool 4 passed through the tool hole a of the axial force applying device 7 is inserted from the upper end opening of the cylinder bore 1a into the bore, and the honing tool 4 is rotated and raised and lowered to Then, honing is performed to obtain a high degree of roundness.

After the honing process is completed, the axial force adding device 7
While rotating the male threaded shaft 7b in the loosening direction using the driving mechanism, the lifting device 8 raises the axial force applying device W7 relative to the cylinder block l, and removes the axial force applying device 7 from the cylinder block l. 1
used in engine assembly.

This method can also bring about the same effects as the previous embodiment, and according to this embodiment, in particular, the application of axial force can be performed automatically and with high precision.

Although the present invention has been described above based on the illustrated example, the present invention is not limited to the above-mentioned example. can be applied to bring about the above-mentioned effects.

(Effects of the Invention) Thus, according to the cylinder bore honing method for an aluminum cylinder block of the present invention, the high roundness achieved by honing can be reproduced even when the cylinder head is attached to the aluminum cylinder block. During engine operation, it is possible to prevent uneven wear of the piston ring and the inner surface of the cylinder bore, and to improve the adhesion of the piston ring to the inner surface of the cylinder bore, reducing oil consumption. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the cylinder bore honing method for an aluminum cylinder block of the present invention, Fig. 2 is an explanatory diagram showing another embodiment of the invention, and Fig. 3 is an explanatory diagram showing a conventional cylinder bore honing method. FIG. 4 is a plan view showing a cylinder head mounting screw hole 1b provided on the upper surface of the cylinder block. 1... Aluminum cylinder block 1a... Cylinder bore

Claims (1)

[Scope of Claims] 1. When honing the inner surface of the cylinder bore of an aluminum cylinder block, while applying substantially the same axial force to the cylinder head mounting screw portion as when the cylinder head is attached, A method for honing the cylinder bore of an aluminum cylinder block, which is characterized by performing honing.