JPH0596540U - Engine assembly - Google Patents

Abstract

(57) [Summary] [Purpose] In an engine assembly in which an aluminum rocker arm 10 is swingably supported on a rocker shaft 12 while leaving a radial gap 14 therebetween, the radial gap 14 is a temperature of a diesel engine. It expands or contracts with changes to prevent slack, seizure, and galling from occurring between rocker arm 10 and rocker shaft 12. [Structure] The rocker shaft 12 is made of austenitic stainless steel.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an engine assembly, and more particularly to an engine assembly including aluminum parts.

[0002]

[Prior Art]

 In engines such as diesel engines, aluminum is used as a material for various parts in order to reduce the weight. In a conventional engine assembly, an aluminum part and a part made of a material other than aluminum such as steel are assembled together.

[0003]

[Problems to be solved by the device]

 The difference in linear expansion coefficient between aluminum and steel is large, and due to the large temperature difference between low temperature and high temperature in the engine, looseness may occur between aluminum parts and steel parts at high temperatures, and However, problems such as seizure and galling occur at low temperatures.

An object of the present invention is to provide an engine assembly which can overcome the above-mentioned problems caused by a temperature difference between an aluminum part and an assembled part to be assembled with each other.

[0005]

[Means for Solving the Problems]

 The invention will be described using the reference numerals of the drawings corresponding to the embodiments. In the engine assembly of the present invention, the aluminum parts (10, 18, 30, 40, 42) and the assembly parts (12, 26, 34, 50) that are mutually assembled are made of stainless steel.

[0006]

[Action]

 Aluminum parts (10,18,30,40,42) and stainless steel assembly parts (12,26,34,50) have a large temperature difference between low temperature and high temperature of the engine. The (10,18,30,40,42) and the assembling parts (12,26,34,50) expand and contract with a substantially equal linear expansion coefficient as the temperature changes.

[0007]

【Example】

 The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 2 is a structural diagram of a range of a rocker arm 10 without a bush of a camshaft type valve opening / closing mechanism in a diesel engine. The rocker arm 10 is made of aluminum, and the rocker shaft 12 is made of an austenitic stainless material having a linear expansion coefficient almost equal to that of the rocker arm 10. The rocker shaft 12 penetrates the rocker arm 10 and swingably supports the rocker arm 10. FIG. 1 is an enlarged view of a through portion of the rocker shaft 12 of FIG. The outer diameter of the rocker shaft 12 is slightly smaller than the inner diameter of the insertion hole of the rocker arm 10, the bush is not installed in the insertion hole of the rocker arm 10, and the radial gap 14 is the outer circumference of the insertion hole of the rocker arm 10 and the outer circumference of the rocker shaft 12. Formed between and to guide the lubricating oil.

Although a large temperature difference occurs between a low temperature and a high temperature of the diesel engine, the rocker arm 10 and the austenitic stainless steel expand and contract with a linear expansion coefficient almost equal to each other, and the radial gap 14 is larger than that of the diesel engine. Despite the large temperature change, the size change is suppressed. The conventional rocker shaft 12 is made of steel, and at a low temperature of the diesel engine, the radial gap 14 is reduced to cause seizure and galling between the rocker arm 10 and the rocker shaft 12, and the diesel engine At high temperature, the radial gap 14 was expanded to promote wear, but in this embodiment, since the radial gap 14 is maintained at an appropriate size, wear, seizure, and galling are prevented. ..

FIG. 3 is a vertical cross-sectional view of one side half of the piston 16 in the diesel engine. The piston body 18 is made of aluminum, and has a recess 20 at the top center that opens to the top surface. The plurality of annular grooves 22 are formed in the circumferential portion of the piston main body 18 side by side in the axial direction, and a piston ring (not shown) is mounted therein. The piston pin through hole 24 radially penetrates the skirt portion of the piston body 18. The cylindrical bush 26 is made of an austenitic stainless steel material, the surface of which is subjected to a nitriding treatment as a load-bearing portion to have enhanced wear resistance, and is press-fitted into the piston pin through hole 24. The piston pin (not shown) is made of steel and is rotatably fitted into the piston pin through hole 24 at its end. The piston 16 undergoes a large temperature difference between a low temperature and a high temperature of the diesel engine, but the cylindrical bush 26 made of austenitic stainless steel expands and contracts with a linear expansion coefficient almost equal to that of the piston body 18 made of aluminum. In the conventional piston 16, the cylindrical bush 26 is made of an iron-based material, and when press-fitting into the piston pin through hole 24, consider looseness between the piston bush through hole 24 and the piston pin through hole 24 at high temperature. In contrast to the necessity, in the embodiment, the cylindrical bush 26 can be press-fitted into the piston pin through hole 24 without considering the looseness.

FIG. 4 is a structural diagram of a range of a rocker arm 28 with a bush 34 of a camshaft type valve opening / closing mechanism in a diesel engine. The rocker arm body 30 has a cylindrical hole 32 that passes through a rocker shaft (not shown) and is made of aluminum. The bush 34 is made of an austenitic stainless steel material, the surface of which is subjected to a nitriding treatment as a load-bearing portion to enhance wear resistance, and is press-fitted into the cylindrical hole 32. The rocker arm 28 undergoes a large temperature difference between a low temperature and a high temperature of the diesel engine, but the bush 34 made of austenitic stainless steel expands and contracts with a coefficient of linear expansion almost equal to that of the rocker arm body 30 made of aluminum. In the conventional rocker arm 28, the bush 34 is made of an iron-based material, and when press-fitting into the piston pin through hole 24, it is necessary to consider looseness between the bush 34 and the piston pin through hole 24 at high temperature. On the other hand, in the embodiment, the bush 34 can be press-fitted into the piston pin through hole 24 without considering looseness.

FIG. 5 is a structural diagram of the large end portion 38 of the connecting rod 36. At the large end 38, an aluminum connecting rod body 40 and a cap 42, both of which are made of aluminum, are joined to each other and fastened to each other by a nut 44. The two semicircular metals 46 are fixed to the inner peripheral surface of the large end portion 38 as the cap 42 is joined to the connecting rod body 40. A crank pin portion (not shown) of the crank shaft is fitted on the inner circumference side of the metal 46 and slides in the inner circumference of the metal 46 in the circumferential direction. FIG. 6 is a perspective view of the metal 46. The backing metal 50 is made of stainless steel (SUS304 or the like) and has a bright plating layer 52 on the surface. The lubricating oil groove 48 is formed on the inner peripheral side of the metal 46, and the lubricating oil is introduced therein. The connecting rod 36 undergoes a large temperature difference between low temperature and high temperature of the diesel engine, but the metal 46 having the stainless steel backing 50 expands with a linear expansion coefficient almost equal to that of the aluminum connecting rod body 40 and the cap 42. Contract. In the conventional connecting rod 36, the backing metal 50 of the metal 46 is made of an iron plate such as SPCC, and when the metal 46 is fixed to the insertion hole of the large end 38, the back stress of the metal 46 is reduced at high temperature and the metal While it was necessary to consider looseness between the 46 and the insertion hole of the large end 38, in the embodiment, it is possible to fix the metal 46 to the insertion hole of the large end 38 without considering them. it can.

[0012]

[Effect of the device]

 In this invention, since the assembly parts to be assembled to the aluminum parts in the engine assembly are made of stainless steel, the aluminum parts can be manufactured despite the large temperature difference between the low temperature and the high temperature of the engine. Also, the stainless steel assembly parts expand and contract with substantially equal linear expansion coefficients, and can prevent loosening, seizure, and galling that occur between the aluminum parts and the assembly parts due to a large temperature difference.

[Brief description of drawings]

FIG. 1 is an enlarged view of a through portion of the rocker shaft of FIG.

FIG. 2 is a structural diagram of a range of a rocker arm without a bush of a camshaft type valve opening / closing mechanism in a diesel engine.

FIG. 3 is a vertical cross-sectional view of one half of a piston of a diesel engine.

FIG. 4 is a structural diagram of a range of a rocker arm with a bush 34 of a camshaft type valve opening / closing mechanism in a diesel engine.

FIG. 5 is a structural diagram of a large end 38 of the connecting rod.

FIG. 6 is a perspective view of a metal.

[Explanation of symbols]

 10 Rocker Arm (Aluminum Component) 12 Rocker Shaft (Assembled Component) 18 Piston Body (Aluminum Component) 26 Cylindrical Bush (Assembled Component) 30 Rocker Arm Body (Aluminum Component) 34 Bush (Assembled Component) 40 Connecting Rod Body (Aluminum parts) 42 Cap (aluminum parts) 50 Back metal (assembly parts)

Claims (1)

[Scope of utility model registration request] 1. An assembly for an engine, characterized in that aluminum parts (10, 18, 30, 40, 42) and assembly parts (12, 26, 34, 50) which are mutually assembled are made of stainless steel. body.