JPH02311262A - Honing process of cylinder - Google Patents

Abstract

PURPOSE:To reduce deformation due to thermal expansion during processing of a cylinder hole, and to perform the process with good accuracy by performing grinding process of a cylinder by a honing grinding stone, letting a fluid cooling medium pass in a tube passage of a cylinder block. CONSTITUTION:During the grinding of a cylinder hole 6 by a honing grinding stone 9, cooling water in a tank 12 is circulated and supplied into a water jacket 7 which is formed in a cylinder block 5 to be ground, by a pump 13 of a circulation device 11. The block 5 is sufficiently cooled thereby, so as to reduce frictional heat caused by the grinding process. Deformation due to thermal expansion is reduced, and the cylinder hole 6 of the cylinder block 5 is ground and processed with a high roundness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for honing a cylinder, for example, for finishing a cylinder block of a water-cooled engine.

(Prior Art) A cylinder block portion of a vehicle engine is shown in FIG. 3, for example. A crankcase section 2 forming the upper part of the crankcase is integrally formed in the lower part of the cylinder block section 1.

During the finishing process of the cylinder hole 3 of the cylinder block portion 1, honing is performed. In this honing process, as shown in FIG. 4, a cylindrical honing wheel 4 is rotated in the circumferential direction and reciprocated along the axis of the cylinder hole 3 to perform spiral grinding.

In such a grinding process, frictional heat is generated between the cylinder hole 3 and the honing wheel 4, resulting in partial thermal expansion of the cylinder block portion 1, which reduces the finishing accuracy of the cylinder hole 3. was there. In addition, the flow of the surface structure and the annealing effect caused by heating are generated.
It was difficult to machine the cylinder hole 3 with highly accurate roundness.

(Problem 8 to be solved by the invention) When honing the cylinder hole of an engine, frictional heat is generated between the honing wheel and the cylinder hole, and this heat causes the cylinder block to deform due to thermal expansion. However, if the cylinder was ground as it was, the cylinder could not be machined with the required accuracy.

The present invention has been made with attention to the above-mentioned problems, and an object of the present invention is to provide a cylinder honing method that can reduce thermal expansion of a cylinder block and grind the cylinder block with high precision.

[Structure of the Invention] (Means and effects for solving the problem) A cylinder hole of a liquid-cooled engine that cools the cylinder block by circulating a liquid cooling medium in a pipe line formed in the cylinder block is formed using a honing wheel. When grinding, by circulating a fluid cooling medium within the pipe line of the cylinder block, heating of the cylinder block due to friction during grinding can be reduced.

(Example) A first example of the present invention will be described with reference to FIG. For example, a cylinder hole 6 is formed in a cylinder block 5 of a water-cooled engine shown in the figure, and a water jacket 7 as a conduit through which cooling water as a fluid cooling medium flows is formed on the wall surface of this cylinder hole 6. has been done.

A grinding device 8 used to grind the cylinder block 5 rotates a cylindrical honing wheel 9 in the circumferential direction, and a drive mechanism 10 that reciprocates in the axial direction.
It is equipped with This grinding device 8 is provided with a cooling water circulation device 11 as a fluid cooling medium. This circulation device 11 is equipped with a cooling water tank 12 and a pump 13 that forcibly circulates water in this cooling water tank 12, and a cooling water circulation path 14 connects the cooling water tank 12 and pump 13. , the cooling water pumped by this pump 13 is transferred to the water jacket 7 of the cylinder block 5.
connected to flow into one end of the The cooling water circulated through the water jacket 7 and discharged from the cylinder block 5 returns to the cooling water tank 12 again.

When performing grinding using the grinding device 8 configured as described above, the honing wheel 9 performs the grinding process, and at the same time, the circulating device 11 circulates cooling water into the cylinder block 5. Thereby, the heat generated by the friction of the honing wheel 9 is exchanged with the cooling water.

Here, in order to perform sufficient heat exchange, the cooling water in the cooling water tank 12 needs to be kept at a constant temperature at all times.

For this reason, it is necessary to increase the capacity of the cooling water tank 12,
It is also conceivable to provide a structure that forcibly cools the water.

By passing cooling water into the water jacket 7 during the grinding process as described above, the cylinder block 5
The material is cooled sufficiently and can be machined with high accuracy and roundness.

Although the fluid cooling medium in this embodiment is water, it is not limited to this, and similar effects can be obtained with cooling oil or the like.

A second embodiment of the present invention will be described below with reference to FIG. The cylinder block 5 shown in the figure is for example a water-cooled engine, and a water jacket 7 as a conduit is formed in the wall surface around the cylinder hole 6.

The grinding device 14 used to grind the cylinder hole 6 of the cylinder block 5 has a cylindrical honing wheel 9, which rotates in the circumferential direction of the cylinder and rotates in the axial direction. A drive mechanism 1 that reciprocates to
0 is set.

The grinding device 14 is also provided with a compressor 15 that pumps air as a fluid cooling medium. A discharge pipe of the compressor 15 is connected to one end of the water jacket 7 of the cylinder block 5, and the air compressed from the compressor 14 is discharged into the atmosphere from the other end of the water jacket 7.

With the grinding device 14 configured in this way, the compressor 15 simultaneously pumps air into the water jacket 7 while the honing wheel 9 is grinding, thereby cooling the cylinder block 5 and reducing the frictional heat caused by the grinding process. Can be reduced.

Then, deformation due to thermal expansion is reduced and grinding with a high degree of roundness can be achieved.

Here, although the fluid cooling medium is air in this embodiment, it is not limited to this, and any gas that can effectively cool the cylinder block 5 is not limited to air. Also,
When using a highly volatile gas, it is conceivable to supply the gas from a gas cylinder instead of the compressor 15.

Note that the present invention is not limited only to the above embodiments. For example, in each of the above embodiments, the cylinder block 5
is for a water-cooled engine, but is not limited to the water-cooled type as long as it is for an engine that cools during operation by passing another liquid cooling medium through the conduit 7 of the cylinder block 5. That is, any method may be used as long as the conduit 7 of the cylinder block 5 used for cooling the engine after completion is used when machining the cylinder hole.

[Effects of the invention] By using the pipe line in the cylinder block used for liquid cooling of the engine after completion as a circulation path for the fluid cooling medium during grinding, thermal expansion deformation during cylinder hole machining is reduced. , high precision machining is possible. This makes it possible to machine cylinder holes with high roundness.

[Brief explanation of drawings]

FIG. 1 is a front sectional view conceptually showing the grinding state of the first embodiment of the present invention, FIG. 2 is a front sectional view conceptually showing the grinding state of the second embodiment of the present invention, and FIG. The figure is a perspective view showing a broken surface of a cylinder block portion of a water-cooled engine, and FIG. 4 is a front sectional view conceptually showing a conventional grinding state. 5... Cylinder block, 7... Water jacket (pipe line), 9... Honing wheel.

Claims (1)

[Claims] In a method for honing a cylinder of a liquid-cooled engine in which a liquid cooling medium is circulated through a pipe line formed in the cylinder block to cool the cylinder block during operation, the fluid cooling medium is passed through the pipe line of the cylinder block. A method for honing a cylinder, the method comprising grinding the cylinder using a honing wheel.