What are the common mechanical failures and solutions for motor automatic rotor spot welding test machine?
Motor automatic rotor spot welding test machine in the process of long-term operation, mechanical parts due to wear and tear, stress and other factors are prone to failure, affecting the normal operation of the equipment and production efficiency. The following are common mechanical failures and corresponding solutions:
I. Transmission system failure
l Failure phenomenon
Belt/chain transmission problems: abnormal noise occurs when the equipment is running, and the transmission belt or chain slips or jumps teeth, resulting in unstable rotor transmission speed or inability to transmit. For example, after the belt slackens, when the rotor is driven to move, there will be slipping between the belt and the pulley, which makes the rotor unable to arrive at the specified position at the predetermined speed.
Gear transmission failure: ear-splitting friction sound at the gear meshing, serious gear wear, broken teeth, resulting in inaccurate transmission ratio, affecting the accuracy of rotor spot welding and testing.
l Cause Analysis
The belt/chain is aged, stretched and deformed after long-term use, and the tension is insufficient; the links of the chain are worn out, resulting in poor meshing with the sprocket.
Insufficient lubrication of gears and long-term dry friction aggravate the wear; insufficient precision of gear installation, the axes of two gears are not parallel or the center distance is inaccurate, resulting in excessive local force; impurities in the working environment enter into the gear meshing parts, accelerating the wear.
l Solution
Regularly check the tension of the belt/chain, use the tensioning device to adjust the tension of the belt, and replace the belt/chain with new parts if it is seriously worn or aged. For the chain, it is also necessary to apply special lubricant regularly to reduce friction and wear.
Re-adjust the installation position of gears to ensure that the axes of the two gears are parallel and the center distance meets the design requirements; strengthen the lubrication management of gears, choose the appropriate gear oil and supplement or replace it on a regular basis; add a protective cover over the gear transmission part to prevent impurities from entering, and replace the gears in time if they are broken or seriously damaged.
Second, positioning and clamping device failure
l Failure phenomenon
Inaccurate positioning: the rotor position is shifted during spot welding and testing, resulting in the wrong position of the welded joints and large deviation of the test data. For example, the axis of the rotor cannot be accurately aligned with the center of the spot welding electrode or test sensor.
Insufficient or uneven clamping force: the rotor loosens during operation, which affects the spot welding quality and test stability, and may even cause the rotor to fly out and cause accidents.
l Cause analysis
The mechanical structure of the positioning device is worn out due to long-term use, such as the positioning pin, the positioning block of the fit gap becomes large; positioning reference surface has bumps, scratches, resulting in a decline in positioning accuracy.
Clamping device cylinder, hydraulic cylinder seals aging, leakage, resulting in insufficient clamping force; clamping mechanism of the connecting rod, lever and other parts of the deformation, so that the distribution of clamping force is not uniform.
l Solution
Repair or replace the worn positioning parts, grind and polish the positioning datum surface, and re-process the positioning parts if necessary; regularly calibrate the positioning device to ensure positioning accuracy.
Replace the aging seals in the clamping device, repair or replace the deformed connecting rod, lever and other parts; adjust the pressure of the cylinder, hydraulic cylinder, so that the clamping force to reach the specified value, and through the pressure sensor and other tools to detect the uniformity of the clamping force, and adjust accordingly.
Third, the guide rail and screw failure
l Fault phenomenon
Guide rail jamming: the moving parts of the equipment do not move smoothly on the guide rail, and there is a jamming phenomenon, resulting in unstable movement speed, or even unable to move, which may be accompanied by abnormal noise.
Deterioration of the precision of the screw drive: when the rotor moves along the direction of the screw, the actual displacement does not match the set displacement, which affects the accuracy of spot welding and testing, and is manifested in the deviation of the position of the welded joints and large fluctuations in the test data.
l Cause analysis
Poor lubrication of the guide rail surface, insufficient lubricant or lubricant deterioration, resulting in increased frictional resistance; iron filings, dust and other impurities on the guide rail, enter between the guide rail and the slider, impeding the movement of the slider.
Screw nut sub-wear, with a larger gap; screw axis and the guideway is not parallel, so that the screw in the movement process of uneven force, accelerating wear; screw support bearing damage, resulting in uneven rotation of the screw.
l Solution
Regularly add the appropriate amount of lubricant for the guide rail, clean the impurities on the surface of the guide rail, you can use brushes, compressed air and other tools to clean; check the installation accuracy of the guide rail, ensure that the guide rail is firmly connected to the base of the equipment, and that the parallelism and straightness are in accordance with the requirements.
Adjust the clearance of the screw nut sub, can be eliminated by adjusting the spacer or the use of double nut preload; recalibrate the parallelism between the screw axis and the guide rail; replace the damaged support bearing, precision testing and repair of the screw, and replace the screw if necessary.
Fourth, spot welding electrode failure
l Fault phenomenon
Electrode wear: The head of spot welding electrode is seriously worn, and the diameter of electrode becomes smaller, resulting in inconsistent diameter of welded joints, decreased welding strength, false welding, desoldering and other problems.
Electrode sticking: In the process of spot welding, the electrode sticks to the rotor surface, causing the electrode surface to be uneven, affecting the welding quality and increasing the frequency of electrode replacement.
l Cause analysis
Poor quality of electrode material, poor wear resistance; spot welding parameters are not set reasonably, such as welding current is too large, welding time is too long, accelerating electrode wear.
The surface of the rotor is not clean, there are impurities such as oil, rust, etc., which adhere to the electrode at high temperatures; the cooling effect of the electrode is not good, and the temperature of the electrode is too high, which leads to the adhesion of the electrode and the rotor material.
l Solution
Choose good quality electrode material with high wear resistance, adjust the spot welding parameters reasonably according to the material of the rotor and welding requirements, such as appropriately reducing the welding current and shortening the welding time; check the electrode wear regularly, and when the electrode is worn to a certain extent, repair or replace it in time.
Before spot welding, clean the surface of the rotor to remove oil, rust and other impurities; optimize the cooling system of the electrode to ensure that the electrode is sufficiently cooled during the welding process, by increasing the flow of cooling water, checking whether the cooling pipe is blocked to improve the cooling effect; if the electrode sticks, clean the surface of the electrode in a timely manner and analyze the reasons for sticking, and take appropriate measures to avoid reoccurrence.
※ If you still can't solve the equipment failure through the above ways and means, please contact the technical specialist of Xinhui Electromechanical Equipment Co.
