JP3039222B2 - Honing method of cylinder block 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 cylinder block bore in which a piston slides.

[0002]

2. Description of the Related Art Conventionally, as a surface property in a cylinder block bore in which a piston slides, a surface roughness as small as possible is effective in reducing friction loss and fuel consumption, and a piston skirt slides. It is said that roughening the surface roughness of the cylinder block bore to increase the oil holding amount is more effective for seizure resistance.

In order to enhance these effects, the surface characteristics of the inner surface of a conventional cylinder block bore are, for example, as shown in Japanese Utility Model Application Laid-Open No. 58-2343, etc. It is known that the surface roughness of the inner surface is made smaller than the surface roughness of the inner surface of the cylinder block bore on which the piston skirt slides.

[0004]

However, in the above-described surface properties of the inner surface of the cylinder block bore, in the vicinity of the piston top dead center where the load is high, the surface roughness becomes rough in order to satisfy the scuff resistance. And the load is large,
Friction is also large. Further, the amount of retained oil is large, and the amount of oil consumed by the combustion temperature is large.

[0005] The surface roughness of the inner surface of the bore other than the top dead center is fine, the thrust load is small, the friction effect is small, the combustion temperature is low, and the oil consumption effect is small.
From the above, it is difficult to obtain a sufficient effect.

SUMMARY OF THE INVENTION An object of the present invention is to improve the scuff resistance, reduce friction and reduce oil consumption of a cylinder block bore at the same time in order to improve the above-mentioned problems. It is to provide a method.

[0007]

[0008]

[0009]

In order to achieve the above-mentioned object, a method for honing a cylinder block bore according to the present invention is performed by a grindstone provided on the outer periphery of the tip of a rotatable and reciprocally movable honing head. When honing the inner surface of the cylinder block bore in which the water jacket is formed, a rigid reinforcing member is fitted into the water jacket corresponding to the thrust and anti-thrust portions where the piston acts in the circumferential direction of the cylinder block bore. It is characterized in that honing is performed with increased rigidity.

[0010] In the honing method,
It is preferable that the rigid reinforcing member is composed of a first reinforcing member having an inclined portion facing outward and downward, and a second reinforcing member engaging with the inclined portion of the first reinforcing member. .

[0011]

By adopting the method for honing a cylinder block bore of the present invention, when the inner surface of the cylinder block bore is honed by a grindstone provided on the outer periphery of the tip of a rotatable and reciprocally movable honing head, In the circumferential direction of the cylinder block bore where the water jacket is formed, the honing process is performed with the rigidity enhanced by fitting a rigid reinforcing member in the water jacket corresponding to the thrust where the piston acts and the anti-thrust part. By doing so, the surface roughness of the thrust and anti-thrust portion is formed relatively coarse, and the thrust,
The surface roughness of portions other than the anti-thrust portion is formed finely. As a result, in the entire cylinder block bore, improvement in scuff resistance, reduction in friction, and reduction in oil consumption are simultaneously achieved.

[0012]

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

Referring to FIG. 2, when the crankshaft 5 is rotated, for example, clockwise in FIG. 2 inside the bore 3 of the cylinder block 1, the piston 9 is reciprocated vertically via the connecting rod 7. Will be. As a result, as shown in FIG. 3, when the piston 9 acts on the inner surface of the bore 3 in the left-right direction 3A, 3B, it receives thrust and anti-thrust.

As shown in FIG. 1, the surface roughness of the thrust portion 3A and the anti-thrust portion 3B on the inner surface of the bore 3 is increased, and the surface roughness of portions other than the thrust portion 3A and the anti-thrust portion 3B is reduced. It is made to be small.

As a result, the surface roughness of the thrust portion 3A and the anti-thrust portion 3B, which have the greatest influence on the scuff, is made coarser than those of the other portions, and as shown in FIG. 3 The amount of oil retained on the inner surface is increased, and the scuff resistance can be improved. At the same time, by reducing the surface roughness other than the thrust portion 3A and the anti-thrust portion 3B, the oil holding amount of the entire bore 3 is reduced,
As shown in FIG. 4B, the oil consumption can be reduced, and the friction coefficient can be reduced as shown in FIG. 4C, so that the friction torque can be reduced.

Here, the surface roughness of the thrust portion 3A and the anti-thrust portion 3B is preferably Ra = 0.3 to 0.6 μ ,
This means that below 0.3 μ , the oil retention properties will be extremely reduced,
On the other hand, if it exceeds 0.6 μ , the friction is greatly increased. The surface roughness of the portion other than the thrust portion 3A and the anti-thrust portion 3B is preferably less than Ra = 0.3 μm . This is because, when it is less than 0.3 μm , the oil holding amount is significantly reduced, and the oil consumption can be greatly reduced.

As means for making the surface roughness of the thrust portion 3A and the anti-thrust portion 3B on the inner surface of the bore 3 larger than the surface roughness of the other portions, as shown in FIGS. A water jacket 11 is formed in the circumferential direction of the block 1. In the circumferential direction of the water jacket 11, a thrust portion 13A and an anti-thrust portion 13B acting when the piston slides are provided.
1 and 2, a first reinforcing member 15 as a rigid reinforcing member having an inclined portion 15S is fitted downwardly and outwardly, and furthermore, the rigidity engaged with the inclined portion 15S is fitted. The second reinforcing member 17 as a reinforcing member is fitted. As a result, the rigidity of the thrust portion 13A and the anti-thrust portion 13B in the water jecket 11 is higher than the other portions.

In this state, the well-known honing head is rotated and reciprocated up and down, so that the inner surface of the bore 3 of the cylinder block 1 is honed by a grindstone provided on the outer periphery of the tip of the honing head. . As a result, the water jacket 11
Since the thrust portion 13A and the anti-thrust portion 13B have higher rigidity than other portions, during the honing process,
The inner surface of the bore 3 in the thrust portion 13A and the anti-thrust portion 13B is honed in a state in which the surface pressure of the grindstone is higher than the inner surface of the bore 3 in other portions.

Therefore, according to the relationship shown in FIG. 7, the thrust portion 13A and the anti-thrust portion 13B
The surface roughness of the inner surface of the bore 3 can be formed to be larger than the surface roughness of the inner surface of the bore 3 in other portions.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

[0022]

As will be understood from the above description of the embodiment, according to the present invention, in the circumferential direction of the cylinder block bore, the water jacket corresponding to the thrust and anti-thrust portions where the piston acts is provided. Since the honing process is performed with the rigidity reinforcing member fitted to increase the rigidity, the thrust acting on the piston, the surface roughness of the anti-thrust portion can be formed to be coarser than the roughness of the other portions, and thus the cylinder block can be formed. In the whole bore,
It is possible to simultaneously improve scuff resistance, reduce friction, and reduce oil consumption.

[Brief description of the drawings]

FIG. 1 is a view showing a main part of the present invention and showing surface roughness from a thrust position where a bore peripheral surface is developed to an anti-thrust position.

FIG. 2 is a schematic front view in which a piston is reciprocated within an inner surface of a bore of a cylinder block.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a diagram showing the relationship between the surface roughness of the inner surface of the bore, scuff resistance, oil consumption, and friction.

FIG. 5 is a plan view showing an example of a cylinder block.

FIG. 6 is a front sectional view of FIG.

FIG. 7 is a diagram showing a relationship between a thrust and an anti-thrust portion and surface roughness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 3 Bore 3A Thrust part 3B Anti-thrust part 9 Piston 11 Water jacket 13A Thrust part 13B Anti-thrust part 15 1st reinforcement member (rigid reinforcement member) 17 2nd reinforcement member (rigid reinforcement member)

Claims (2)

(57) [Claims] When a honing process is performed on an inner surface of a cylinder block bore in which a water jacket is formed with a grindstone provided on an outer peripheral portion of a front end of a rotatable and reciprocally movable honing head, a circumferential direction of the cylinder block bore is used. A method of honing a cylinder block bore, characterized in that a stiffening member is fitted in a water jacket corresponding to a thrust and an anti-thrust portion on which a piston acts, and the stiffness is increased to improve stiffness. 2. The rigid reinforcing member includes a first reinforcing member having an inclined portion facing outward and downward, and a second reinforcing member engaging with the inclined portion of the first reinforcing member. The honing method for a cylinder block bore according to claim 1, wherein: