How to process the engine conrod?

The structure of the engine conrod

The role of the engine conrod

workpiece material and blank

The process of engine conrod

The structure of the engine conrod

Engine conrods are extremely critical parts for gasoline engines and diesel engines. There are many varieties and huge quantity demands. Among them, the demand for automobile engines is the most. For example, 4420300220 conrod is a common truck part connecting rod. Today, the editor will take you to understand the relevant knowledge of the engine conrod.

1. The structure of the engine conrod

The engine conrod is a slender non-circular rod with variable cross-section, and its shaft cross-section gradually decreases from the big end to the small end to adapt to the drastically changing dynamic load during work. It is composed of a connecting rod big end, a shaft and a connecting rod small end. The big connecting rod end is separated, half is integrated with the shaft, and half is a connecting rod cover. The connecting rod cover is assembled with the crankshaft main journal with bolts and nuts. Together.

2. The role of the engine conrod

The connecting rod connects the piston and the crankshaft, and transmits the force exerted by the piston to the crankshaft, and converts the reciprocating movement of the piston into the rotational movement of the crankshaft. It is one of the main transmission components of the automobile engine. It transmits the pressure of the expanding gas acting on the top of the piston to the crankshaft, so that the reciprocating linear motion of the piston becomes the rotary motion of the crankshaft to output power.

3. Workpiece material and blank

The materials of the engine conrods are mostly selected high-strength 45 steel, 40Dr steel, etc., and are quenched and tempered to improve cutting performance and increase impact resistance. The hardness of 45 steel is HB217-293, and 40Dr is HB223-280. There are also nodular cast iron and powder metallurgy technology, which can reduce the cost of the blank.

The blanks of steel engine conrods are generally produced by forging. There are two blank forms: one is to forge the body and cover separately; the other is to forge the body and cover into one body, and then cut or use it in the process of processing. Expansion break process will break it. In addition, in order to avoid defects in the blank, 100% hardness measurement and flaw detection are required.

4. The process of engine conrod

Take 4420300220 conrod as an example, let’s understand some of the process of engine conrod.

1) The roughing stage of 4420300220 conrod

The roughing stage is also the processing stage before the engine conrod and the cover are merged: mainly the engine conrod reference surface processing, including the auxiliary reference surface processing, the preparation of the connecting rod body and the processing of the cover combination, such as the milling of the two facing surfaces , Grinding, etc.

2) The semi-finishing stage of 4420300220 conrod

The semi-finishing stage is also the processing after the engine conrod and the cover are combined, such as precision grinding of two planes, semi-finished floor large-end holes and orifice chamfering, etc. In short, it is the stage of preparation for finishing large and small head holes.

3) the finishing stage of 4420300220 conrod

The finishing stage is mainly to ensure that all the large and small holes on the main surface of the engine conrod meet the requirements of the drawings, such as honing of large-head holes and fine-boring small-head bearing holes.

The above is the related introduction about the engine conrod. If you have more questions, please contact Guangzhou Hui Yuan Mechanical & Electrical Co., Ltd.!

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