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Method for testing preload of engine connecting rod bolt and special tool thereof

A technology of bolt pre-tightening force and engine connecting rod, which is applied in the direction of measuring torque/torsion force, measuring device, force/torque/work measuring instrument during tightening, etc. , The strain gauge requirements are very high, affecting the normal operation of the friction pair, etc., to achieve the effect of easy operation, low difficulty, and easy lead

Inactive Publication Date: 2011-03-23
CHONGQING CHANGAN AUTOMOBILE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the structural characteristics of the connecting rod group itself: the polished rod part of the connecting rod bolt and the connecting rod body are interference fit, so the bolt itself is under a certain pressure, and the strain is attached to the polished rod part of the connecting rod bolt, which requires high requirements for machining and strain gauges. In addition, the measurement results will be affected to a certain extent; if a strain gauge is attached to the threaded part of the connecting rod bolt, the thread will be damaged and the normal operation of the friction pair will be affected.
Therefore, it is difficult to directly measure the pretightening force of connecting rod bolts

Method used

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  • Method for testing preload of engine connecting rod bolt and special tool thereof
  • Method for testing preload of engine connecting rod bolt and special tool thereof
  • Method for testing preload of engine connecting rod bolt and special tool thereof

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Embodiment Construction

[0032] Using the method of the invention to test the pretightening force of the engine connecting rod bolts includes two testing processes: the first process is a torque test; the second process is a pressure test.

[0033] First step: torque test, such as figure 1 As shown, the process includes:

[0034] Step 1: Paste strain gauges on the outer side of the connecting rod cover, and there is a strain gauge 7 on the intake side and exhaust side respectively.

[0035] Step 2: The strain gauge 7 is connected to an external strain measuring device.

[0036] Step 3: Place the connecting rod horizontally on the support block 3, and fix the small head 2 of the connecting rod with the support block with bolts.

[0037] Step 4: Use a torque wrench to tighten the connecting rod bolts and nuts 1 according to the assembly process requirements, and read the strain and ε of the connecting rod cover under the specified tightening torque through the strain measuring device C .

[0038] ε ...

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Abstract

The invention provides a method for testing the preload of an engine connecting rod bolt and a special tool thereof. The method comprises two steps of torque test and pressure test and is in particular as follows: sticking a strain gage on the parting surfaces at the two sides of a connecting rod cap, measuring the strain and preload of the connecting rod cap and further obtaining the preload of the connecting rod bolt. The special tool comprises a force transfer part and a support part, which transmits the external force to the connecting rod cap by using a pressure method to test. By adopting the method in the invention, changes are hardly carried out on the connecting rod, thus being capable of measuring the actual strained condition of the connecting rod bolt with accurate test and easy operation.

Description

technical field [0001] The invention relates to a method for testing the pretightening force of engine connecting rod bolts and a special tool used in the method. Background technique [0002] The pretightening force of engine connecting rod bolts is a parameter that must be strictly controlled in engine design and manufacture. When the engine is assembled, after the connecting rod bolts are tightened according to the design requirements and the torque specified in the assembly specifications, the pretightening force of the connecting rod bolts can generally meet the static strength design requirements. In the actual assembly process, due to various factors such as insufficient tightening torque and changes in the friction coefficient between friction pairs, the pre-tightening force of the connecting rod bolts is insufficient, resulting in loosening of the connecting rod bolts, and even damage to the working engine in severe cases. Therefore, it is very necessary to measure...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01L5/00G01L5/24
Inventor 杨金利刘祖国余涛吴顺洪贾健科江宝宇
Owner CHONGQING CHANGAN AUTOMOBILE CO LTD
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