JPH0730899Y2 - Piston structure of internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston structure of an internal combustion engine having a cutout portion for avoiding interference of an injection nozzle at a lower end portion.

As is well known in the prior art, for example, in an automobile internal combustion engine, lubricating oil is sprayed from below to the inside of the piston during reciprocating motion in the cylinder bore to positively cool the piston to sufficiently reduce the thermal effect on the piston. The device to do is made.

FIG. 2 shows a V-type internal combustion engine 1 provided with such a piston cooling mechanism, which is formed in the lower deck 2a located between the cylinder bores 3, 3 of the cylinder block 2 having a V bank angle, inside the lower deck 2a. Oil main gallery 4
A pair of left and right injection nozzles 5 and 6 communicating with the injection nozzles 5 and 6 bent upward from the lower ends of the cylinder bores 3 and 3 are provided.
Lubricating oil is injected from the injection holes 5a and 6a to positively cool the pistons 7 and 8 in the cylinder bores 3 and 3, respectively.
On the other hand, substantially arched notches 9 and 10 are formed at the lower ends of the skirts 7a and 8a of the pistons 7 and 8, respectively, in the notches 9 and 10 near the bottom dead center of the pistons 7 and 8. The injection nozzles 5 and 6 are accommodated to avoid interference between the injection nozzles 5 and 6 and the piston skirt portions 7a and 8a.

This makes it possible to set the height of the engine as low as possible while ensuring a sufficient stroke range of the pistons 7 and 8 (see Japanese Utility Model Laid-Open No. 61-53517, etc.).

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the V-type internal combustion engine, each injection nozzle
5, 6 are extended from the lower deck 2a between the cylinder bores 3, 3 to the left and right sides in relation to the formation position of the oil main gallery 4 for introducing lubricating oil. Therefore, each piston 7,
The notches 9 and 10 formed in 8 are also formed in different positions of the left and right pistons 7 and 8 corresponding to the positions of the injection nozzles 5 and 6, respectively. Therefore, it is impossible to share the pistons 7 and 8 with each other, and when the pistons 7 and 8 are assembled to the cylinder bores 3 and 3, respectively, check the notches 9 and 10 that match the injection nozzles 5 and 6, respectively. I have to keep it. As a result, the work of assembling the pistons 7 and 8 becomes complicated, which not only lowers the work efficiency but also raises the cost.

Means for Solving the Problems The present invention has been devised in view of the conventional circumstances described above,
On the premise of an internal combustion engine provided with a cylinder block having left and right independent cylinder rows, in particular, notches for interference avoidance are formed at two positions on the lower end of the skirt corresponding to the positions of both the left and right injection nozzles, and each notch is formed. It is characterized in that the reinforcing portion formed around the portion is composed of an alumina-silica fiber composite material.

Action According to the above configuration, it is possible to assemble either piston to the left and right cylinder bores, that is, the piston can be shared, and therefore the assembling workability is improved.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
Since this embodiment is also applied to the V-type internal combustion engine as in the conventional case, the same reference numerals will be given to the common constituent portions for description.

That is, inside the lower end of the lower deck located between the left and right cylinder bores of the V-shaped cylinder block, a pair of left and right injection nozzles that communicate with the oil main gallery are provided, and each of these injection nozzles has an injection hole at the tip of the cylinder bore. It is bent and extends upward from the lower end toward the inside.

And the aluminum alloy piston 7 in each cylinder bore
As shown in FIG. 1 (one piston is shown for convenience), one of the above injection nozzles is provided near the bottom dead center position of the piston 7 at two positions on both sides of the lower end of the skirt 7a sandwiching the boss 7b. Substantially arcuate notches 11 and 12 for accommodating are formed. That is, the notches 11 and 12 are formed at the positions corresponding to any of the injection nozzles in a state where the piston 7 is assembled in either the left or right cylinder bore.
Reinforcing parts 13 and 14 are formed around the notches 11 and 12. The reinforcing portions 13 and 14 are made of an alumina-silica fiber composite material.

Therefore, according to this embodiment, when the piston 7 reaches the vicinity of the bottom dead center position, the tip of the injection nozzle is housed in one of the notches 11 and 12, and the injection nozzle and the skirt 7 are formed.
Not only the interference with a is avoided, but the piston 7
When assembling into the left and right cylinder bores, it can be assembled without considering the compatibility between the injection nozzle and one notch portion in advance as in the conventional case. That is, since one piston 7 can be commonly used, the work of assembling the cylinder bore is facilitated, and the work efficiency can be improved.

Further, since the reinforcing portions 13 and 14 are formed near the notches 11 and 12, and the reinforcing portions 13 and 14 are composed of the alumina-silica fiber composite material, the rigidity is increased and the lateral thrust acting on the skirt portion 7a is increased. The load can be sufficiently countered. Therefore, it is possible to sufficiently prevent the occurrence of cracks or damage near the notches 11 and 12.

The present invention can be applied to not only the V type but also the horizontally opposed type internal combustion engine.

EFFECTS OF THE INVENTION As is clear from the above description, according to the piston structure of the internal combustion engine according to the present invention, the notch is formed at the lower end of the skirt corresponding to both the left and right injection nozzle positions. The left and right cylinder rows can be shared. Therefore, the manufacturing cost of the piston can be reduced, and the assembling work to the cylinder bore can be facilitated, and the work efficiency can be improved and the work cost can be reduced. In particular,
According to the present invention, since the reinforcing portion formed around the cutout portion is formed of the alumina-silica fiber composite material, the rigidity around the cutout portion is increased, and the thrust load can be sufficiently resisted. It is possible to prevent cracks and damages from occurring in the vicinity.

[Brief description of drawings]

FIG. 1 is a front view of a piston showing an embodiment of the present invention, and FIG. 2 is a sectional view of a V-type internal combustion engine to which a conventional piston structure is applied. 1 ... V type internal combustion engine, 2 ... cylinder block, 2a ...
Lower deck, 5,6 …… Injection nozzle, 7,8 …… Piston, 1
1,12 …… Notch part, 13,14 …… Reinforcement part.

Claims (1)

[Scope of utility model registration request] 1. A cylinder block having independent left and right cylinder rows is provided with injection nozzles for respectively injecting lubricating oil to the left and right pistons, and at the bottom end of the skirt of each piston near the bottom dead center position. In the internal combustion engine in which the interference avoiding cutouts of each of the injection nozzles are formed, the cutouts are formed at two positions of the lower end of the skirt corresponding to both the left and right injection nozzle positions, and the cutouts of the respective cutouts are formed. A piston structure for an internal combustion engine, characterized in that a reinforcing portion formed on the periphery is made of an alumina-silica fiber composite material.