Mazda CX-5 Service & Repair Manual: Connecting Rod, Connecting Rod Bearing

Mazda CX-5 Service & Repair Manual / Engine / Engine Assembly / Piston Assembly / Connecting Rod, Connecting Rod Bearing

Purpose, Function

Connecting rod

The connecting rod transmits the reciprocating movement of the piston to the crankshaft by engaging the piston pin and crank pin.

Connecting rod bearing

The connecting rod bearing forms an oil film on the outer surface of the crank pin to prevent wear due to sliding.

Construction

Connecting rod

The connecting rod is installed between the piston pin and crank pin.
High-strength, forged carbon steel has been adopted for weight reduction.
A cracking method*1 for breaking off and separating the connecting rod from the connecting rod cap has been adopted for improved accuracy.
Weight has been reduced by optimizing the shape from the I shaft to the large end.
Reciprocating inertial weight, including the piston, has been reduced with the use of a full-float type for the connection with the piston and further tapering of the small end shape.
With the adoption of the plastic region tightening*2 method for the connecting rod bolt, the stability of the axial force has been improved.

*1 Method of breaking off the large end proportion of the connecting rod after it has been integrally molded to separate the connecting rod from the connecting rod cap. When assembling the connecting rod and connecting rod cap, dowel pins are required to use the mating surface shape which was created during breaking process.

*2 Plastic region tightening is a method of controlling the tightening using the rotation angle of a bolt. By tightening to the region (plastic tightening region) in which bolt deformation does not become irreversible, variation in axial force is suppressed.

Connecting rod bearing

The connecting rod bearing is installed on the outer surface of the crank pin.
The upper and lower connecting rod bearing are made of aluminum alloy.

Piston Assembly

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Piston, Piston Ring, Piston Pin

Purpose, Function Piston The piston in the cylinder of the cylinder block moves reciprocally by the pressure received when the air-fuel mixture combusts. Piston ring The piston ...

Other materials:

Oil Control Valve (OCV)
Purpose, Function The OCV switches the oil passage to the hydraulic variable valve timing actuator to control the opening/closing period of the exhaust valve. Construction The OCV is installed to the exhaust camshaft cap (No.1). The OCV consists of a spool valve wh ...

Discharge Headlight Control Module
Purpose Converts DC voltage from the battery to AC voltage and outputs the stabilized voltage to the discharge headlight. Function The discharge headlight control module controls the voltage from the battery to illuminate the discharge headlight. The discharge headl ...

Crankshaft, Main Bearing
Purpose, Function The crankshaft converts the reciprocating movement of the piston to a rotational movement via the connecting rod. The main bearing forms an oil film on the outer surface of the crankshaft journal to prevent wear due to sliding. Construction Crankshaft ...