行业组件数据 · 2026

主轴承盖

Main bearing caps are precision-engineered components that secure crankshaft bearings within engine cylinder blocks, ensuring proper alignment and load distribution.

技术定义与适配语境
典型 主轴承盖 会按材料、尺寸公差、适配关系和失效风险在 汽车制造 中评估。

Main bearing caps are structural components bolted to the cylinder block's main bearing saddles to retain the crankshaft main bearings. They provide precise alignment for the crankshaft, maintain bearing clearances, and distribute combustion and inertial loads throughout the engine block. These caps are critical for maintaining crankshaft concentricity, minimizing vibration, and ensuring proper oil film formation in hydrodynamic bearings.

组件规格

定义
Main bearing caps are structural components bolted to the cylinder block's main bearing saddles to retain the crankshaft main bearings. They provide precise alignment for the crankshaft, maintain bearing clearances, and distribute combustion and inertial loads throughout the engine block. These caps are critical for maintaining crankshaft concentricity, minimizing vibration, and ensuring proper oil film formation in hydrodynamic bearings.
工作原理
Main bearing caps function by clamping the upper half of main bearings against the cylinder block's bearing saddles, creating a circular housing for the crankshaft journals. When torqued to specification, they maintain precise bearing clearance (typically 0.0005-0.0025 inches) for hydrodynamic lubrication. The caps transfer crankshaft loads into the cylinder block structure while preventing bearing rotation and maintaining oil pressure in the lubrication system.
材料
Typically forged or cast steel (SAE 11414140or 4340 alloy steel) for high-strength applicationsductile iron (ASTM A536) for cost-effective solutionsaluminum alloys (A356-T6) in some lightweight designs. Heat treatment includes quenching and tempering to achieve 28-32 HRC hardness.
Bolt Torque
80-120 ft-lbs (108-163 Nm)
Weight Range
0.5-3.0 kg per cap
Surface Finish
16-32 μin Ra (0.4-0.8 μm Ra)
Bearing Clearance
0.0008-0.0020 inches (0.020-0.051 mm)
Dimensional Tolerance
±0.0005 inches (±0.013 mm)
标准
ISO 286-2DIN 3760SAE J429ASTM A536

行业分类与别名

主轴承盖 的常用贸易名称、技术标识和检索关键词。

上级产品

该组件会出现在以下整机或工业产品中。

FMEA · 风险与缓解

诱因 → 失效模式 → 工程缓解

Insufficient bolt torque or uneven tightening sequence->Bearing cap movement leading to bearing spin and engine seizure->Use calibrated torque wrenches and follow manufacturer tightening patterns
Material fatigue from cyclic loading->Crack propagation through cap cross-section->Regular inspection for stress cracks and proper material selection
Improper bearing clearance during assembly->Insufficient oil film causing bearing overheating and scoring->Precision measurement of bearing clearances using plastigage

工业生态与工程逻辑

0
Bearing bore distortion
1
Improper bearing clearance
2
Fatigue cracking
3
Bolt thread stripping
4
Oil leakage from cap interfaces

合规与检测

tolerance
Bearing bore diameter tolerance: H7/h6 fit; Bolt hole positional tolerance: ±0.002 inches
test method
Dye penetrant inspection for cracks; Coordinate measuring machine (CMM) verification; Ultrasonic testing for material integrity

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采购评估维度

不是客户评论,也不是实时热度。以下维度用于前期 RFQ 准备和供应商评估。

技术文档
4/5
制造能力
4/5
可检验性
5/5
供应商透明度
3/5

这些分值是采购评估维度示例,不代表真实客户评分、具体国家买家反馈或实时询盘。

相关组件

常见问题

What happens if main bearing caps are over-torqued?

Over-torquing can distort bearing bores, causing improper crankshaft alignment, reduced bearing clearance, and potential bearing failure due to insufficient oil film thickness.

Can main bearing caps be reused after engine disassembly?

Yes, if undamaged and properly torqued in original positions. They must be kept with their original cylinder block and installed in the same orientation and sequence.

What causes main bearing cap walk?

Cap walk occurs from insufficient bolt torque, worn bolt threads, or excessive crankshaft end play, allowing lateral movement that damages bearing surfaces and oil seals.

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CNFX Industrial Component Index · 汽车制造

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URN:CNFX:ME:UNIT:MAIN_BEARING_CAPS