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 Type | Straight-Sided Internal Spline |
| Spline Standard | GB, ISO, and other standards |
| Number of Teeth | Customizable |
| Bore Diameter | Customized to the mating external spline shaft |
A rectangular internal spline sleeve is an internal spline component featuring straight-sided rectangular teeth. It normally works with a matching external spline shaft to form a spline connection, where multiple tooth flanks share the transmitted load to provide torque transmission, axial positioning, and a reliable shaft-to-hub connection.
Compared with conventional key connections, rectangular splines distribute the load across multiple tooth flanks, providing more uniform load distribution and reliable connections. They are suitable for applications requiring higher torque transmission, fixed connections, or axial sliding connections. Depending on the design and applicable standard, tooth count, tooth width, bore and outside diameters, spline length, fit tolerances, and accuracy requirements can be customized.
Rectangular internal spline sleeves can be manufactured from materials such as 45 steel, 40Cr, and 42CrMo according to the load and operating environment. Heat treatments such as quenching and tempering or induction hardening can further improve the wear resistance of the spline tooth flanks and extend service life. They are widely used in mechanical transmission systems, construction machinery, agricultural machinery, machine tools, and industrial equipment.
A rectangular internal spline sleeve uses a straight-sided rectangular tooth profile, with multiple spline teeth evenly distributed around the bore. Torque is transmitted through the tooth flanks in contact with the mating external spline shaft. The relatively simple tooth geometry facilitates manufacturing and mating, while tooth count, tooth width, bore and outside diameters, spline length, and fit tolerances can be designed according to application requirements.
Compared with a conventional single-key connection, rectangular splines distribute the transmitted load across multiple tooth flanks, helping reduce localized stress and providing a reliable shaft-to-hub connection within a limited space.
A rectangular internal spline sleeve normally forms a spline pair with an external spline shaft, transmitting rotational torque through tooth flank contact. Depending on the equipment design, it can be used for either fixed or axial sliding connections to meet different requirements for power transmission and axial movement.
Rectangular splines provide good torsional strength and connection rigidity, making them suitable for medium-low-speed and medium-load transmission applications. Proper control of spline dimensions, fit clearance, material, and heat treatment can improve tooth flank wear resistance, connection stability, and service life.
Rectangular internal spline sleeves offer a simple structure, mature manufacturing processes, reliable power transmission, and easy assembly and disassembly. They are suitable for shaft-to-hub connections in mechanical transmission systems, construction machinery, agricultural machinery, machine tools, and industrial equipment. Spline dimensions, fit tolerances, materials, and heat treatment can be customized according to the operating conditions.
| Parameter | Standard Mass-Production Model (General Service) | High-Precision Custom Model (Precision Transmission) |
| Core Connection Specifications | ||
| Spline Type | Straight-Sided Internal Spline | Precision internal spline; non-standard designs available |
| Spline Standard | Specified according to drawing and mating spline standard | GB, ISO, and non-standard requirements supported |
| Number of Teeth | Designed according to torque and structural requirements | Optimized for load, service life, and fit accuracy |
| Tooth Width | Designed according to spline size and load requirements | Optimized for load capacity and fit accuracy |
| Bore Diameter | Designed to match the 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 capacity |
| Spline Length | Designed according to connection length and application requirements | Optimized according to load and accuracy requirements |
| Fit Type | Fixed or axial sliding fit | 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 application and applicable standard | High-precision dimensional and fit control available |
| Profile Accuracy | Standard spline machining | Optimized tooth profile and width accuracy |
| Fit Accuracy | Standard fit control | Precision control of tolerance, concentricity, and clearance |
| 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, induction hardening, and other surface hardening treatments |
| Machining Processes | Broaching, shaping, sizing, and other processes | Broaching, shaping, sizing, precision finishing, and other processes |
| Surface Treatment | Black oxide, phosphating, rust prevention | Precision corrosion protection and special surface treatments |
| Remarks | The above are standard machining parameter ranges for our straight-sided 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, number of teeth, bore diameter, spline length, 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.
Steel (Representative Grades: 45 Steel / C45
45 steel offers a good balance of mechanical properties, machinability, and cost. After quenching and tempering, it provides good strength and toughness, making it suitable for 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 tooth flank hardness and wear resistance, making them suitable for construction machinery, gear reducers, and medium- to high-load transmission systems.
Representative Grades: 20CrMnTi, 20CrMo
20CrMnTi and 20CrMo develop a hard surface layer and tough core after carburizing and hardening, providing good wear resistance, fatigue strength, and impact resistance. They are suitable for automotive transmissions, heavy-duty machinery, and long-term operating spline connections.
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. Typical applications include food, pharmaceutical, and chemical equipment.
Representative Grade: 38CrMoAl
38CrMoAl has good nitriding characteristics and can achieve high surface hardness, wear resistance, and dimensional stability after nitriding while retaining good core toughness. It is suitable for precision transmission systems and high-accuracy spline connections.
Representative Grades: QT450, QT500
Ductile iron combines good strength, wear resistance, and vibration damping, making it suitable for larger spline sleeves operating at low speeds and under medium loads. It can be used in general machinery, agricultural equipment, and industrial transmission systems.
Rectangular internal spline sleeves connect shafts with gears, couplings, and other rotating components, providing reliable torque transmission and axial positioning. Their compact design and easy assembly make them suitable for various power transmission applications in automotive and vehicle systems.
In construction machinery, tractors, harvesters, and other agricultural equipment, rectangular internal spline sleeves are used to connect drive shafts, transmission shafts, and actuating components. With materials such as 40Cr and 42CrMo and suitable heat treatment, they can support long-term operation under medium and fluctuating loads.
Rectangular internal spline sleeves are used to connect shafts with gears, sleeves, and other components in machine tools and general transmission equipment. Proper control of spline dimensions and fit tolerances provides reliable positioning and power transmission for both fixed and axial sliding connections.
In automation equipment, conveyors, gear reducers, and industrial transmission systems, rectangular internal spline sleeves connect input shafts, output shafts, and other drive components. Spline dimensions, materials, and fit accuracy can be customized according to torque, installation space, and assembly requirements.
In gear reducers, transmission boxes, and power transmission systems, rectangular internal spline sleeves connect shafts with gears, couplings, and other drive components. Multiple spline teeth help distribute the load, while spline dimensions and fit can be designed according to torque and installation requirements.
In industrial robots, automated actuators, and precision motion equipment, rectangular internal spline sleeves connect drive shafts with actuating components. Precise control of spline dimensions, fit tolerances, and concentricity helps meet requirements for repeatable motion, accurate 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 
