Overview of lead screw backdriving

1.Leadscrew backdriving definition and reasons

(1) Definition
Lead screw backdriving refers to lead screw reverse rotation image due to external load or internal factors in the transmission process.

(2) Reasons
Reverse drive may be caused by a variety of factors,such as excessive load,transmission system clearance,insufficient friction coefficient and so on.

2.Reverse transmission has an impact

(1)Reduced transmission accuracy
The reverse drive will cause the transmission precision of leadscrew to decrease and affect the normal operation of the equipment.

(2)Increase energy consumption
Reverse transmission will increase the energy consumption of the transmission system and reduce the working efficiency of the equipment.

(3)Shorten service life
Long-term reverse transmission will accelerate the wear of lead screw and shorten its service life.

3.The importance of preventing reverse transmission
(1)Improve equipment performance
Preventing reverse transmission can improve the transmission accuracy and work efficiency of the equipment,thereby improving the overall performance of the equipment.

(2)Ensure safe production
Reverse transmission may cause equipment failure or damage,and preventing reverse transmission helps to ensure production safety.

(3)Extend service life
The effective prevention of reverse transmission can reduce the wear of leadscrew,extend its service life and reduce maintenance costs.

 

Method of preventing reverse transmission

1.Structural design optimization
(1) Add a backstop structure
A certain depth and width of the backcheck groove is processed on lead screw.When lead screw is subjected to reverse force,the backcheck groove interacts with the matching part to prevent lead screw from reverse-driving.

(2)Install the backcheck
A backstop is installed at one or both ends of lead screw.When lead screw is subjected to reverse force,the backstop will automatically lock to prevent the lead screw from reverse-driving.

(3)Optimize thread type
●Select appropriate thread type
According to the transmission requirements,select the appropriate thread type,such as trapezoid,sawtooth,etc.,to improve transmission efficiency and self-locking performance.

●Optimized thread parameters
The transmission performance and self-locking performance of lead screw can be improved by optimizing the parameters of thread height, pitch and profile Angle.

 

(4)Improve machining accuracy and surface quality

●Improve machining accuracy
Adopt high-precision processing equipment and technology to ensure the processing accuracy and dimensional stability of lead screw.

●Improve surface quality
By heat treatment,surface spraying and other processes,the surface hardness and wear resistance of lead screw are improved,and the friction coefficient is reduced,so as to improve the transmission efficiency and self-locking performance.

 

2.The stiffness and damping of the transmission system are improved
(1) Enhance the stiffness of the supporting structure
●Choose high strength materials
Such as high-quality alloy steel or composite materials to improve the bearing capacity and deformation resistance of the supporting structure.

●Optimize the shape of the support structure
Design reasonable support structure shape,such as box structure,floor structure, etc.,to improve the overall stiffness of the structure.

●Increase the cross-section size of the support structure
By increasing the cross-section size of the support structure,the flexural and torsional stiffness of the support structure are improved,thus reducing the deformation in the transmission process.

 

(2) Add damping materials or devices

●Use of damping materials
Damping materials,such as rubber and silicone,are added to the transmission system to absorb vibration energy and reduce shock and vibration during the transmission process.

●Mounting damper
Install dampers at key parts,such as hydraulic dampers,gas dampers, etc.,to provide additional damping force and suppress the vibration of the drive system.

●Vibration damping device is used
Damping devices,such as shock absorbers and vibration pads,are added to the transmission system to reduce the vibration and noise generated during the transmission process

 

(3) Optimize the transmission system layout

●Rational arrangement of transmission components
According to the stress and movement characteristics of the transmission system,the transmission elements are rationally arranged to reduce the deformation and vibration in the transmission process. 

●Use a balancing mechanism

Add a balance mechanism in the transmission system,such as a balance wheel,balance block, etc.,to balance the torque and inertial force in the transmission process.

●Optimized transmission path
By optimizing the transmission path,reducing the transmission link and transmission ratio,reducing the energy loss and vibration in the transmission process.

3.Improved friction and lubrication conditions

(1) Choose the right lubricant
● Consider lubricant viscosity
Choose a lubricant with a moderate viscosity to reduce friction and reverse drive risk.

● High and low temperature resistance
Ensure that the lubricant maintains stable performance over the operating temperature range of the keystone screw.

● Wear resistance
Use lubricants with anti-wear properties to extend the service life of lead screw.

 

(2) Optimize the lubrication method

●Periodic lubrication
Formulate a reasonable lubrication cycle to ensure that lead screw is timely and fully lubricated.

●Proper lubrication

Avoid excessive lubrication resulting in lubricant overflow,resulting in resource waste and environmental pollution.

●Lubrication point setting

Set the lubrication point at the key friction part of the trapezoidal lead screw to ensure that the lubricant can accurately reach the friction surface.

(3) Improve the material pairing of friction pairs
●Choose wear-resistant materials
Select a material with excellent wear resistance for lead screw to improve its wear resistance.

●Optimized material mix

According to the working conditions and requirements of lead screw,the friction pair material is reasonably matched to reduce the friction coefficient.

●Consider material compatibility
Ensure that the selected materials maintain good compatibility under the action of lubricants to avoid chemical reactions between materials that lead to performance degradation.

 

4.External factors control and maintenance

(1) Control ambient temperature and humidity
●Maintain a suitable ambient temperature
Avoid lead screw working in high or low temperature environment to reduce the influence of thermal expansion or cold contraction on transmission accuracy.

●Control ambient humidity
Excessive humidity may lead to corrosion or rust on the surface of lead screw,which will affect its transmission performance,so it is necessary to keep the ambient humidity within a reasonable range.

(2) Avoid overload or impact load
●Defined maximum load
According to the design parameters and use requirements of lead screw,the maximum load is reasonably limited to avoid damage or reverse transmission of lead screw caused by overload.

●Mitigation of impact load
A buffer device is added to the transmission system or a flexible connection is adopted to reduce the impact load on lead screw.

 

(3) Regular inspection and maintenance

●Periodic inspection
Regular lead screw for comprehensive inspection,including its surface condition,lubrication,tightness,etc.,to ensure that it is in good condition.

●Maintenance
According to the use of lead screw and maintenance requirements,timely lubrication,cleaning,adjustment and other maintenance work to extend its service life and maintain transmission accuracy.