Spline Shaft Transmission Component For 7mm Cordless Electric Drills

Spline Shaft Transmission Component For 7mm Cordless Electric Drills

I. Basic Functions —— “Power Transmission Shaft” of the Electric Drill
The spline shaft is a key transmission component between the gearbox and the chuck/output shaft of the electric drill, undertaking three core tasks:
1.Power Transmission
The high - speed rotation output by the electric drill motor is transmitted to the chuck through the meshing of spline teeth, driving the drill bit to rotate. With multi - tooth contact, compared with single - key transmission, the torque - carrying capacity is increased by 3 - 5 times (matching the 10 - 50N·m torque requirement of a 7mm electric drill).
2.Torque Adaptation
The involute spline tooth profile (or rectangular spline) of the spline shaft can optimize the tooth profile to make the torque distribution more uniform and avoid local stress concentration. During frequent start - stop and load changes of the electric drill, it reduces the wear of shaft teeth and prolongs the service life.
3.Precision Guiding
The coaxiality accuracy of the spline shaft ensures the transmission concentricity between the motor and the chuck, making the rotation runout of the drill bit ≤ 0.1mm, improving the drilling accuracy, and avoiding the deviation and breakage of the drill bit.

II. Coordination with the Electric Drill Mechanism —— “Rotation + Impact” Dual Modes
If the electric drill has an impact function, the spline shaft needs to cooperate with an impact block/clutch to realize the “rotary cutting + axial impact” composite action:
1.Pure Rotation Mode (e.g., Drilling Wood, Plastic)
The spline shaft directly meshes with the output gear of the gearbox, uniformly transmits the motor torque, and drives the chuck to drive the drill bit to rotate. The rotation speed is adjusted by the gearbox to match the drilling requirements of different materials.
2.Impact Rotation Mode (e.g., Drilling Concrete, Brick Wall)
The spline shaft is linked with an impact block (with bevel teeth). During rotation, the spline teeth push the impact block to move axially and collide with the fixed impact block, generating high - frequency impact. The high - strength material of the spline shaft can withstand the impact load and ensure the stable operation of the impact function.

III. Key Design —— “Miniaturization + High Reliability” for Electric Drills
To meet the compact space and high reliability of 7mm cordless electric drills, the spline shaft has these special designs:
1.Size and Precision
▶Small shaft diameter (matching a 7mm drill chuck, the outer diameter of the spline shaft ≤ 10mm), using a small - diameter centering rectangular spline, with a tooth width of 2 - 4mm, ensuring the torque - carrying capacity in a small size.
▶The spline tooth are processed by hobbing + grinding, with a tooth profile accuracy of grade 7 - 8 and a surface roughness Ra ≤ 0.8μm, reducing meshing noise and improving transmission efficiency.
2.Material and Heat Treatment
Medium - carbon alloy steel is selected. After quenching and tempering, the spline teeth are induction - hardened, and the core remains tough, resisting torsion and breakage while being wear - resistant.
3.Anti - loosening and Assembly
The spline shaft and the output end of the gearbox adopt an interference fit + retainer ring positioning. After assembly, the axial runout ≤ 0.1mm, avoiding the loosening of the spline shaft caused by the vibration of the electric drill; when matching with the spline sleeve of the chuck, elastic retainer rings or thread locking are used to ensure transmission reliability.

IV. Failure Modes and Service Life Guarantee
The common failures of the spline shaft of the electric drill include tooth surface wear, tooth root fracture, and spline slip, which can be avoided through design optimization:
1.Tooth Surface Wear: Adopting hard chrome plating or nitriding treatment, the tooth surface hardness is increased to HRC60 - 65, and the wear - resistant service life is extended by 2 times.
2.Tooth Root Fracture: Optimizing the fillet of the spline tooth root, reducing the stress concentration factor, and avoiding tooth root cracking under impact load.
3.Spline Slip: Controlling the interference of the tooth side and cooperating with the elastic expansion of the spline sleeve to prevent load - induced slip.

This set of spline shafts is the “power backbone” of 7mm cordless electric drills: it transmits torque through multi - tooth meshing, adapts to both pure rotation and impact rotation modes, and with miniaturized and high - precision design, ensures the drilling accuracy and reliability of the electric drill in a narrow space and variable loads. The coordinated optimization of its material, process, and precision enables the small - sized shaft to carry large torque, supporting the full - scenario application of the electric drill from home DIY to light industrial operations —— A small shaft drives great energy and is the core transmission foundation for the efficient operation of the electric drill.

DINGSCO Precision Gear Solutions — Pioneering Force in Equipment Transmission

Core Advantages: Cutting-Edge Equipment × Digitalized Processes × Full-Cycle Services

As a leading precision gear manufacturer, DINGSCO specializes in customized production of micro high-precision spiral bevel gears and hypoid gears through our multiple CNC seven-axis five-linkage spiral bevel gear grinding/milling machines and Gleason spiral bevel cutter technology. With DIN 6 precision class (tooth profile error ≤ ±5μm), 95%+ transmission efficiency, and ultra-high reduction ratios, we deliver reliable transmission solutions for robotics, motor drives, new energy vehicles, and more.

Why Choose DINGSCO?
✅ High Precision: Achieving DIN 6 grade accuracy, leading the industry in controlling tooth profile errors.
✅ High Efficiency: With a single - stage reduction ratio of up to 300:1, and a transmission efficiency of over 95%.
✅ Durability: 40% lower lifecycle cost, <0.5% failure rate.
✅ Fast response: The digital process can shorten the delivery cycle to 20 working days.

Contact Us Soon for gear optimization proposals and 3D meshing simulations!

Our company was formerly known as Changsha Double Star Gear Industrial Co., Ltd, which was established in 1994. It is a directly affiliated university-run enterprise founded by Central South University Professor Zeng Tao, the leading expert on spiral bevel gears in China. It was later renamed as Changsha Senjie Gear Co., Ltd (abbreviated as "CSG") in 2016. CSG is a production R&D base specializing in professional design, reserch, manufacture and sales of high-quality small module spiral bevel gears and high reduction hypoid gears and cylindrical gears. In 2023, Hunan Dinghan New Material Technology Co., Ltd. was established as a specialized international export business department. CSG has strong scientific research and development capabilities and is also equipped a full set of advanced equipment including seven-axis five-linkage CNC spiral bevel gear grinding machines and gear milling machines. By making the best use of the scientific and technological achievements and equipment of the Gear Research Institute of Central South University, machanical processing, heat treatment and testing. We have developed high-quality products featuring high reduction, high speed, heavy load, low noise and less teeth for users.

With the quality policy of "scientific and technological innovation, quality first, being first-class firm and customer‘s satisfaction", we have won the trust of well-known domestic and abroad enterprises with stable and excellent quality. It is committed to be a pioneer of the industry of China's small-module spiral bevel gears, and is dedicated to providing service for any related industry requiring industrial robots, CNC turning and milling compound power tool turrets, industrial sewing machines, reducers, bicycles, power tools and aeromodelling. We sincerely look forward to your cooperation!