Focusing on the design, manufacturing processes, heat treatment techniques, and key quality control points for all types of standard and non-standard gears.
| Parameter | Specification |
| Spline Standard | DIN, ISO, GB, etc. |
| Module | Customizable |
| Pressure Angle | Customizable |
| Bore Diameter | Customizable |
An involute internal spline sleeve is a shaft-hub connection component with an involute tooth profile. It normally mates with an external spline shaft to transmit torque through multiple tooth flanks. It also provides axial positioning and a reliable mechanical connection.
Compared with conventional keyed connections, involute splines use multiple teeth to share the transmitted load. They offer good load capacity, balanced load distribution, and stable centering. The spline design can be adapted to different standards, tooth counts, modules, and fit requirements. It is suitable for medium- to high-torque and continuous-duty transmission systems.
Different materials and heat treatment processes can be selected according to the application. The sleeve can also be customized based on customer drawings, samples, and technical specifications.
The bore of an involute internal spline sleeve features an involute spline tooth profile. The spline teeth are evenly distributed around the bore. They engage with a matching external spline shaft to transmit torque.
Tooth geometry can be designed according to the applicable spline standard, number of teeth, module, pressure angle, and fit requirements. This helps maintain dimensional accuracy and proper mating performance within the spline pair.
Compared with triangular splines, involute splines offer a higher degree of standardization, good load capacity, and better interchangeability. They are suitable for higher-torque and continuous-duty transmission applications.
An involute internal spline sleeve normally forms a spline pair with an external spline shaft. Multiple tooth flanks share the transmitted load to provide stable torque transmission.
Depending on the connection design, the spline pair can be used for either fixed or axial sliding connections. This allows the assembly to meet different requirements for positioning and axial movement.
Involute splines distribute the transmitted load across multiple teeth. With proper design, accurate fitting, and suitable lubrication, they can provide stable transmission performance.
Appropriate material selection and heat treatment can further improve spline flank wear resistance and fatigue performance. These measures also help support reliable operation over long service periods.
Involute internal spline sleeves offer good load capacity, stable mating performance, interchangeability, and broad application versatility. They are commonly used in automotive transmissions, construction machinery, agricultural machinery, gear reducers, machine tools, and industrial transmission equipment.
Depending on the operating conditions, spline dimensions, fit tolerances, materials, and heat treatment can be customized to meet specific transmission and connection requirements.
| Parameter | Standard Mass-Production Model (General Service) | High-Precision Custom Model (Precision Transmission) |
| Core Connection Specifications | ||
| Spline Type | Straight cylindrical involute internal spline | Precision involute spline; non-standard designs available |
| Spline Standard | Specified according to drawing and mating spline standard | DIN, ISO, GB, and non-standard requirements supported |
| Pressure Angle | Determined according to the applicable standard | Optimized for the mating external spline and accuracy requirements |
| Number of Teeth | Designed according to shaft diameter, torque, and structural requirements | Optimized for load, service life, and fit accuracy |
| Module | Customized according to spline specifications and transmission requirements | Optimized for load capacity and precision fit |
| Bore Diameter | Designed to match the mating external spline shaft | Precision control of bore diameter and fit tolerance |
| Outside Diameter | Designed according to installation space and structure | Optimized for wall thickness, rigidity, and load requirements |
| Spline Length | Designed according to connection length and application requirements | Optimized for load and fit accuracy |
| Fit Type | Fixed or axial sliding connection | Precision fixed or sliding fit |
| Fit & Accuracy Specifications | ||
| Centering Method | Determined according to the applicable standard and mating structure | Precision control of centering accuracy and clearance |
| Accuracy Grade | Determined according to product structure and application requirements | High-precision dimensional and fit control available |
| Tooth Profile Accuracy | Standard precision machining | Optimized tooth profile, tooth thickness, and fit accuracy |
| Fit Accuracy | Standard spline fit control | Precision control of flank clearance, concentricity, and fit consistency |
| Materials & Manufacturing Capabilities | ||
| Material Selection | 45 Steel, 40Cr, 42CrMo, stainless steel, and other materials | 42CrMo, 20CrMnTi, 20CrMo, and other alloy steels |
| Heat Treatment | Quenching and tempering, induction hardening | Carburizing and hardening, nitriding, and other surface treatments |
| Machining Processes | Broaching, shaping, sizing, and other processes | Precision shaping, grinding, sizing, and finishing |
| Surface Treatment | Black oxide, phosphating, and rust prevention | Precision corrosion protection and special surface treatments |
| Remarks | The above are standard machining parameter ranges for our involute internal spline sleeves. Special sizes and non-standard structures can be custom-made according to your drawings or samples. For a quotation, please provide the spline standard, pressure angle, number of teeth, module, bore diameter, material, accuracy requirements, and quantity. | |
High-quality blanks are forged and normalized to eliminate internal stress and stabilize material structure.
Turning, milling and hobbing/shaping are applied to form the target tooth profile with strict accuracy control.
Carburizing quenching or tempering processes to improve tooth surface hardness and core toughness.
Grinding of tooth flanks, bores and datum faces to correct deformation and enhance meshing precision.
Full-dimensional verification by gear measuring center and CMM to qualify products before release.
Professional anti-rust and protective packaging to keep products intact during storage and transit.
High-precision gear grinding delivers tooth surface roughness as low as Ra 0.4, with tight meshing, low vibration and noise for smoother equipment operation.
Premium materials matched with precise heat treatment ensure wear-resistant tooth surfaces and impact-resistant core, cutting maintenance and replacement costs.
Custom solutions for high-speed heavy load, corrosion resistance and food-grade scenarios, eliminating trial-and-error costs in product selection.
Scaled production supports tiered pricing for bulk orders with consistent quality; full-process control guarantees stable lead time and complete after-sales support.
Representative Grade: 45 Steel / C45
45 steel offers a good balance of strength, toughness, and machinability at a moderate cost. Quenching and tempering or surface hardening can improve spline flank wear resistance. It is suitable for fixed or sliding spline connections in general machinery, agricultural equipment, and medium-load applications.
Representative Grades: 40Cr, 42CrMo
40Cr and 42CrMo provide high strength, toughness, and fatigue resistance. Quenching and tempering or induction hardening can improve spline flank hardness and wear resistance. They are suitable for automotive transmissions, construction machinery, gear reducers, and medium- to high-load industrial drive systems.
Representative Grades: 20CrMnTi, 20CrMo
20CrMnTi and 20CrMo develop a hard surface layer and tough core after carburizing and hardening. They provide good wear resistance, fatigue strength, and impact resistance, making them suitable for automotive transmissions, heavy-duty machinery, and high-load spline connections for continuous operation.
Representative Grade: 38CrMoAl
38CrMoAl can achieve high surface hardness, wear resistance, and dimensional stability after nitriding while retaining good core toughness. It is suitable for precision gear reducers, machine tools, automation equipment, and other high-precision transmission systems.
Representative Grades: 304, 316, 420
Stainless steel offers good corrosion resistance and environmental durability. 304 and 316 are suitable for humid and corrosive environments, while 420 can achieve higher hardness and wear resistance through heat treatment. It is commonly used in food, pharmaceutical, chemical, and other corrosion-sensitive transmission equipment.
Representative Grades: QT450, QT500
Ductile iron combines good strength, wear resistance, and vibration damping. It is suitable for larger spline sleeves operating at low speeds and under medium loads, and can be used in general machinery, agricultural equipment, and industrial systems. High-load applications are typically better suited to alloy steel.
Involute internal spline sleeves are widely used in transmissions, drive shafts, clutches, and other automotive components. They provide reliable connections between shafts, gears, and sleeves while transmitting torque and providing axial positioning. They are suitable for both mass production and replacement applications.
In construction machinery, tractors, harvesters, and other agricultural equipment, involute internal spline sleeves connect drive shafts, gears, and transmission components. They can handle substantial torque and fluctuating loads, making them suitable for demanding conditions and long-term operation.
Involute internal spline sleeves connect shafts with transmission components in gear reducers, transmission boxes, and other power transmission equipment. They provide stable torque transmission and component positioning, making them suitable for medium- to high-load and continuous-duty industrial transmission systems.
In CNC machine tools, automation equipment, and precision transmission mechanisms, involute internal spline sleeves provide accurate fits and consistent assembly performance. Precise control of spline dimensions, tolerances, and machining accuracy helps improve positioning accuracy and operating stability.
In hydraulic pumps, hydraulic motors, and other power transmission equipment, involute internal spline sleeves connect input and output shafts for reliable torque transmission. Proper material selection and heat treatment can improve spline flank wear resistance and extend service life.
In industrial robots, automated actuators, and precision motion equipment, involute internal spline sleeves connect drive shafts with actuating components. Precise control of spline dimensions, fit tolerances, and concentricity supports repeatable motion, reliable positioning, and stable power transmission.
Inner VCI vacuum anti-rust process fully seals tooth flanks and critical machined surfaces, effectively resisting salt spray and moisture during ocean and air freight to keep precision gears corrosion-free throughout long-distance transit.
We select cost-effective logistics channels with stable transit time and controlled costs. Full logistics tracking is available with real-time status updates to ensure reliable and punctual delivery.
All products are covered by a 1-year warranty. Quality defects caused by non-human factors are fully guaranteed, removing your procurement concerns.
Our professional technical and after-sales team is always available to respond quickly to inquiries and after-sales needs, and efficiently resolve issues during installation and operation.
We support full-parameter OEM/ODM customization based on 2D/3D drawings or physical samples, including module, tooth profile, material and heat treatment specifications. You only need to provide core gear parameters, detailed drawings or physical samples to start the customization process.
You can send physical samples to us via international courier. Upon receipt, we will complete full-dimensional measurement and parameter verification, then arrange sample production after confirming the solution, ensuring the finished product fully matches the original in installation dimensions and transmission performance.
Prototype orders usually ship within 15–25 days, subject to heat treatment and grinding scheduling. Lead time for bulk orders will be confirmed after process finalization, with stable and well-managed production schedules.
We adopt a tiered pricing policy — the larger the order quantity, the more favorable the unit price. All orders follow the same production and quality inspection standards with strict accuracy control. Quality will never be compromised for larger order volumes.
We can include dimensional inspection reports, hardness test records and material certificates with each shipment. For high-precision key projects, professional inspection data from CMM and gear measuring centers is also available.
All products come with a 1-year warranty covering material defects and manufacturing quality issues under normal use. We also have a professional technical team to provide full-process consultation and selection support.
Spur gears feature a simple structure and no axial load, ideal for medium-low speed general transmission with higher cost-effectiveness. Helical gears run smoother with lower noise and higher load capacity, suitable for high-speed heavy-duty applications. We can recommend the optimal solution based on your actual requirements.
+86 184 3796 0706 
info@destinytrans.com 
