JP2579078Y2 - Internal combustion engine piston - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a piston of an internal combustion engine.

[Conventional technology]

In response to the trend toward higher engine speeds in response to the trend toward higher engine output in recent years, there has been an increasing demand for improved accuracy in weight variation of main motion components in each cylinder, which greatly affects the reduction of engine vibration.

Conventionally, as shown in FIG. 3, a weight adjustment pedestal B (shown by hatching) is provided below a pin boss A in order to control the weight variation accuracy of the piston which is the main motion system component. By adjusting the allowance for each cylinder, the accuracy of variation in the absolute weight of the piston is controlled.

[Problems to be solved by the invention] However, in such a conventional example, a pedestal for weight adjustment is provided below the pin boss of the piston,
Since the allowance for weight adjustment is within the range of the length of the skirt in the axial direction of the piston pin and the minimum thickness of the pin boss portion, there is a problem that the allowance for weight adjustment required for precision control of weight variation cannot be secured. Was.

This is particularly noticeable when an oil jet escape cutout C is provided below the piston skirt in a piston cooling oil jet engine. That is, in forming the notch C, in order to secure the strength of the skirt D of the piston, the length of the skirt D in the axial direction of the piston pin is reduced, and the size of the oil jet escape notch C in the skirt D is reduced. Although it is necessary to minimize the length of the skirt D, the length of the skirt D also reduces the weight adjustment allowance.

An object of the present invention is to solve such a conventional problem and to reduce the length of the skirt in the axial direction of the piston pin, and to secure a weight adjustment allowance required for the accuracy control of the weight variation. It is to provide a piston.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, a notch (8) of a piston cooling oil jet (7) is formed in a skirt (2) below a pin boss (3) supporting a piston pin (4). In a piston of an internal combustion engine, a weight adjustment pedestal (9) is provided below the pin boss (3), the weight adjustment pedestal (9)
The pin boss (3) and the skirt (2) are formed so as to be connected to each other, so that the lower portion of the pin boss (3) and the lower end surface of the skirt (2) are integrally connected, and the piston pin (4) is formed. And protrudes from the lower end surface of the skirt (2) in the axial direction to a position at which it does not interfere with the counterweight of the crankshaft.

[Action]

According to the present invention, the weight adjustment pedestal is provided to protrude from the lower end surface of the skirt in the axial direction of the piston pin. Therefore, the adjustment allowance can be sufficiently taken, and the adjustment of the weight variation can be surely performed by cutting off a necessary portion.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 and 2 are views showing an embodiment of the present invention.

In the drawing, 1 is a piston, 2 is a skirt formed below the piston 1, 3 is a pin boss supporting a piston pin 4, 5 is a skirt provided on the skirt 2 in accordance with the lower position height of the pin boss 3. It is a reinforcing rib. A slipper 6 is provided below the skirt reinforcing rib 5 in a direction orthogonal to the axis of the piston pin in a plan view of the piston 1, and a cutout 8 is formed in the slipper 6 to allow a piston cooling oil jet 7 to escape. ing. The slipper 6 has a shorter length in the axial direction of the piston pin 4 so that the notch 8 becomes smaller (coincides with the lower end surface of the skirt 2). The weight adjustment pedestal 9 includes the pin boss 3 and the skirt 2 The lower part of the pin boss 3 and the lower end face of the skirt 2 are integrally connected to each other so that the lower end face of the skirt 2 in the axial direction of the piston pin 4 interferes with the counterweight of the crankshaft. It is projected to a position where it is not sized (indicated by hatching with a two-dot chain line).

In the present embodiment having the above-described configuration, when adjusting the weight variation of the piston 1 for each cylinder, a dimension position where the lower end surface of the skirt 2 in the axial direction of the piston pin 4 does not interfere with the counterweight of the crankshaft. The weight adjustment pedestal protruding up to this may be cut off within a range up to the minimum thickness required for the strength of the pin boss 3. Thus, it is possible to shorten the length of the skirt in the axial direction of the piston pin while securing the weight adjustment allowance required for accuracy control of the weight variation of the piston, and the notch 8 for the oil jet escape becomes smaller, and the slipper 6 The strength of the skirt 2 can be secured.

[Effect of the invention]

As described above, according to the present invention, the notch (8) of the piston cooling oil jet (7) is formed in the skirt (2) below the pin boss (3) supporting the piston pin (4). In addition, in the piston of the internal combustion engine in which a weight adjustment pedestal (9) is provided below the pin boss (3), the weight adjustment pedestal (9) includes the pin boss (3) and the skirt (2). So that the lower part of the pin boss (3) and the lower end surface of the skirt (2) are integrally connected,
Since it protrudes from the lower end surface of the skirt (2) in the axial direction of the piston pin (4) to a position that does not interfere with the counterweight of the crankshaft, it is possible to secure a weight adjustment allowance required for accuracy control of piston weight variation. The length of the skirt, and thus the overall height of the piston, can be shortened, which can cope with a high engine speed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, FIG. 2 is a low elevation view of the same, and FIG. 3 is a sectional view showing a conventional example. 2 ... skirt, 3 ... pin boss, 4 ... piston pin, 9 ... weight adjustment base.

Claims (1)

(57) [Scope of request for utility model registration] 1. A notch (8) of a piston cooling oil jet (7) is formed in a skirt (2) below a pin boss (3) supporting a piston pin (4), and said pin boss (3) is formed. A weight adjustment pedestal (9) is provided at a lower portion of the piston, and the weight adjustment pedestal (9) is formed so as to connect the pin boss (3) and the skirt (2). The lower portion of the pin boss (3) and the lower end surface of the skirt (2) are integrally and continuously connected, and the lower end surface of the skirt (2) in the axial direction of the piston pin (4) is connected to the counterweight of the crankshaft. A piston for an internal combustion engine, wherein the piston protrudes to a position where it does not interfere.