JPH058382Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a support structure for a piston, and more specifically, to attenuate the high frequency component of the combustion explosive force applied to the piston so as not to transmit it to the connecting rod. The present invention relates to a piston support structure configured as described above.

[Prior art]

Generally, a piston support structure for an internal combustion engine such as a diesel engine is such that a piston is connected and supported via a piston pin to a fitting hole formed at the small end of a connecting rod, for example.

By the way, in the above-mentioned diesel engine, the vibration component of combustion (explosion) pressure due to combustion in the engine is transmitted almost undamped to the piston → piston pin → connecting rod, and then further to the connecting rod. There was a problem in that vibrations were transmitted from the rod via the crankshaft to the cylinder block, cylinder head, auxiliary equipment, etc., producing noise typical of diesel engines.

Therefore, in the past, in order to attenuate the high frequency component generated when the vibration component due to the combustion pressure of the engine is transmitted from the piston to the piston pin to the connecting rod as described above, the
As disclosed in Publication No. 12656, the fitting hole formed at the small end of the connecting rod into which the piston pin fits is filled with an organic material such as tetrafluoroethylene (Teflon), oil-resistant, and heat-resistant. It has been proposed that an elastic member made of hard rubber is provided and the high frequency vibrations are attenuated by the elastic force of the elastic member.

However, in such conventional systems, when the piston is displaced a lot due to the combustion pressure of the engine, the piston and cylinder head or supply/discharge valve interfere with each other due to the elastic force of the elastic member, so this cannot be achieved in a diesel engine. It was hot.

That is, it is well known that if the clearance between the piston and the cylinder head changes by 0.1 mm, the performance will change drastically.

Furthermore, in the conventional type, lubricating oil cannot be used, and problems such as seizure may occur.

On the other hand, Utility Model Application Publication No. 57-164229 discloses a structure in which a layer of sintered alloy impregnated with an organic elastic material such as nylon or polyester is integrally formed around the outer periphery of a metal cylinder, and this is fixed in the fitting hole of the piston. It is proposed in the official gazette. However, during engine operation, this piston receives heat from the combustion chamber and reaches a high temperature, and the gap between the fitting hole of the piston and the fitting part of the piston pin widens due to thermal expansion. Even if provided, high frequency vibrations cannot be damped and engine vibration noise cannot be reduced.

Furthermore, in this known technique, there is a tendency for the piston and cylinder head or supply/discharge valve to interfere with each other due to large deformation of the elastic member due to combustion pressure.
This cannot be applied to diesel engines that operate at high temperatures and pressures.

[Purpose of invention]

This idea was devised by focusing on the conventional problems, and its purpose is to attenuate the high frequency component of the combustion explosive force applied to the piston so that it is not transmitted to the connecting rod. The present invention similarly provides a piston support structure that significantly reduces vibration noise during engine combustion.

[Structure of the idea]

In order to achieve the above object, this invention involves fitting a cylindrical laminated body into a fitting hole formed at the small end of the connecting rod, and inserting a piston pin into the hole of this cylindrical laminated body into a piston. In the fixed piston support structure, the cylindrical laminate is composed of a conrod metal located in an inner layer and a plurality of thin-walled cylindrical members that can mutually slide concentrically. It is.

[Example of idea]

Embodiments of this invention will be described below based on the accompanying drawings.

The attached drawing shows a sectional view of a piston 1 in which this invention is implemented, 2 is a connecting rod, 3 is a connecting rod, and 3 is a connecting rod.
indicates a piston pin, and the piston 1 is connected and supported in a fitting hole 4 formed in the small end 2a of the connecting rod 2 via the piston pin 3.

The inner wall surface of the fitting hole 4 formed in the small end 2a is provided with a plurality of layers of thin cylindrical members (in this embodiment, a conrod metal 7 located in the inner layer and a plurality of thin cylindrical members that can mutually slide concentrically). A cylindrical laminated body composed of three layers (6a, 6b, 6c) is fitted, and the piston pin 3 is inserted into the hole of this cylindrical laminated body, and the piston pin 3 is fixed to the piston 1.

Note that 8 is a snap spring, which has grooves 1b formed at both ends of the boss portion 1a to prevent the piston pin 3 from coming out of the boss portion 1a of the piston 1.
is embedded in.

Next, the action will be explained. Now, when the combustion explosion pressure F of the engine acts on the top of the piston 1 from the direction of the arrow, this pressure becomes
It acts on the inner wall surface of the fitting hole 4 formed in the small end 2a of the connecting rod 2.

At this time, since there is a slight clearance between the front and back surfaces of each thin-walled cylindrical member 6a, 6b, 6c with a multilayer structure that is press-fitted into the fitting hole 4, the thin-walled cylindrical member 6
a, 6b, and 6c are slightly deformed in the direction in which the combustion explosion pressure F acts. At this time, each thin cylindrical member 6a,
Coulomb friction acts on the front and back surfaces of 6b and 6c, and damps relatively high-frequency vibrations caused by combustion explosive force.

As a result, the combustion explosion pressure F acting on the piston 1 is not transmitted to the connecting rod 2.
Therefore, the vibrations generated by being transmitted from the connecting rod 2 to the cylinder block, cylinder head, auxiliary equipment, etc. via the crankshaft (not shown) are attenuated, and the noise peculiar to diesel engines can be effectively prevented. It is possible.

[Effect of idea]

This idea is based on a piston support structure in which a cylindrical stack is fitted into a fitting hole formed at the small end of the connecting rod, and a piston pin inserted through the hole in the cylindrical stack is fixed to the piston. In,
The cylindrical laminate is a piston support structure composed of a conrod metal located in the inner layer and a plurality of thin-walled cylindrical members that can mutually slide concentrically, and has the following effects. can. In other words, the combustion explosive force applied to the piston due to the mutual sliding movement of the cylindrical laminated bodies is attenuated by the subtle movement and friction between the cylindrical laminated bodies, and the combustion explosive force is reduced. High frequency vibrations are hardly transmitted to the small end of the connecting rod. As a result, vibration noise generated by high-frequency vibrations during engine operation can be significantly reduced, and a quiet engine can be provided.

Furthermore, there is no interference between the piston and the cylinder head or the supply/exhaust valve, and it can be effectively used as a support structure for the piston of a diesel engine in particular. In addition, the multiple layers of thin-walled cylindrical members are constantly cooled by engine oil and are provided between the low-temperature connecting rod fitting hole and the piston pin fitting part, so the piston temperature It is possible to attenuate high-frequency vibrations without being affected by the vibrations of the engine, and it is possible to reduce vibrations of the engine.

[Brief explanation of the drawing]

The drawing is a sectional view of this invention. 2... Connecting rod, 2a... Small end, 3... Piston pin, 3a... Fitting part, 4...
...Fitting hole, 6a, 6b, 6c...thin cylindrical member.

Claims (1)

[Scope of utility model registration request] In a piston support structure in which a cylindrical laminate is fitted into a fitting hole formed in a small end of a connecting rod, and a piston pin inserted through the hole in the cylindrical laminate is fixed to the piston, the cylindrical The shaped laminate is a piston support structure consisting of a conrod metal located in the inner layer and multiple layers of thin-walled cylindrical members that can mutually slide concentrically.