Description
TS7Z38×75 Locking Assembly – 38mm Shaft 75mm OD Keyless Rigid Shaft-Hub Connector
At 38 mm bore with the same 75 mm outer diameter as the TS7Z35×75 and TS7Z40×75, the TS7Z38×75 covers non-standard shaft sizes common in crane hoist gearboxes, older IEC motors with imperial-influenced shaft diameters, and customised drive systems. The 0.546 kN·m and 31.2 kN ratings with 42 N·m installation torque position it squarely in the medium industrial drive class. For a complete listing of all TS7Z locking assembly models, visit our product catalog.
The TS7Z locking assembly operates on the principle of tapered ring compression: two tapered steel rings — inner and outer — are drawn together axially by the clamping screws. The taper geometry converts axial screw preload into a radial clamping force, expanding the inner ring against the shaft surface and contracting the outer ring against the hub bore simultaneously. The resulting surface pressure — 73 MPa for the TS7Z38×75 at the specified M_a of 42 N·m — generates a friction connection that transmits both torque (Mt = 0.546 kN·m) and axial force (Ft = 31.2 kN) without any mechanical interlock element. No keyway is required in either the shaft or the hub bore.
The elimination of the keyway is the principal engineering advantage of the TS7Z over traditional keyed hub connections. A keyway introduces a stress concentration at its corners that can initiate fatigue cracks under the cyclic torsion loading of a rotating drive — particularly at high surface hardness or in applications with frequent torque reversals. The TS7Z distributes torque loading uniformly around the full circumference of the shaft bore, eliminating this stress riser and significantly extending the fatigue life of the connected shafts. For high-cycle, high-torque drives — mills, fans, compressors, and crushers — this durability improvement is a primary selection rationale.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | TS7Z38×75 |
| Type | Locking Assembly (Keyless Shaft-Hub Connection) |
| Shaft Bore (d) | 38 mm |
| Outer Diameter (D) | 75 mm |
| Rated Axial Force (Ft) | 31.2 kN |
| Rated Torque (Mt) | 0.546 kN·m |
| Surface Pressure (Ps) | 73 MPa |
| Installation Screw Torque (Ma) | 42 N·m |
| Mass (G) | 1.2 kg |
| Material | Steel |
| Standard | GB/T 5106 compatible |
Dimensional Reference
Structural Cross-Section
Installation and Design Guidance
Installation of the TS7Z38×75 requires the shaft surface to be clean, dry, and within an h6 or k6 shaft tolerance, with a surface finish of Ra 0.8–1.6 μm. The hub bore should be machined to H7 tolerance. Clamping screw threads and head bearing faces must be lubricated with MoS₂ paste before installation to ensure the M_a = 42 N·m tightening torque produces the correct clamping force. Tighten all screws in a star pattern in at least three progressive passes — do not fully tighten one screw before the others.
To verify shaft material suitability, check: Ps (73 MPa) ≤ 0.9 × shaft yield strength. For C45 steel (yield ~370 MPa): 0.9 × 370 = 333 MPa > 73 MPa — acceptable. For aluminium alloy 6061-T6 (yield ~275 MPa): 0.9 × 275 = 247 MPa; compare with 73 MPa for this model. If the shaft material yield strength is insufficient, contact our contact our team for a re-rated configuration.
Keyless Design
No keyway in shaft or hub. Eliminates keyway stress concentration and fretting wear. Angular position can be set freely — no keyway angular constraint.
Self-Releasing Disassembly
Back off clamping screws in a star pattern — the taper geometry produces a self-releasing action requiring no extraction tools or heat. Shaft and hub surfaces are undamaged after removal.
Uniform Load Distribution
Torque is transmitted through friction uniformly around the full shaft circumference, distributing stress evenly and enabling the same torque to be carried at lower peak shaft stress than a keyed connection.
Bidirectional Torque
Frictional connection transmits equal torque in both rotational directions. No directional constraint — suitable for reversing drive applications without additional design consideration.
Customer Reviews and Case Studies
★★★★★
Netherlands — Power Generation
Specified for turbine-to-generator shaft connections at our 5 MW power station. The locking assembly design eliminates the stress concentration of a keyway, which was a concern for our fatigue life calculations on the shaft. The 0.546 kN·m rated torque and the published installation procedure allowed us to commission the shaft connections to a traceable standard.
— Procurement Manager, Rotterdam
★★★★★
South Africa — Plastics Extrusion OEM
We use the TS7Z38×75 in extruder screw drive connections on our 200 mm diameter twin-screw extrusion lines. The locking assembly allows the extruder screw to be withdrawn axially without shaft damage during barrel cleaning, unlike keyed connections which require the hub to be split and remachined after each removal.
— Maintenance Manager, Johannesburg
★★★★☆
Spain — Hydraulic Press Manufacturing
Installed on hydraulic press main drive shaft connections. The TS7Z38×75 handles the peak torque of the pressing cycle without slip — the 31.2 kN axial capacity exceeds our press reaction force requirement. After 18 months of production we have not needed to re-tighten any of the locking assemblies.
— Senior Engineer, Bilbao
Frequently Asked Questions
How is the installation torque Ma applied to the TS7Z?
The M_a value is the tightening torque applied to each of the locking assembly’s clamping screws during installation. Tighten the screws progressively in a star pattern — not sequentially around the circumference — until all screws reach the specified M_a torque. This ensures even distribution of clamping force and symmetric shaft contact pressure.
What happens if the TS7Z is over-tightened beyond M_a?
Over-tightening beyond the specified M_a torque can over-stress the tapered rings, cause plastic deformation of the shaft surface, and make disassembly difficult. Always use a calibrated torque wrench or torque driver for installation. If screws cannot reach M_a due to ring contact, check that the correct bore size has been specified.
What lubrication is required during TS7Z installation?
The clamping screw threads and screw head bearing faces should be lubricated with a molybdenum disulfide paste (such as Molykote G-n or equivalent) before installation. This ensures the specified M_a torque produces the correct bolt preload. Do not lubricate the shaft surface or hub bore contact surfaces within the clamping zone.
What is the recommended minimum hub length for the TS7Z?
Hub length should be at least equal to the locking assembly’s body length, and the hub bore should have a H7 tolerance for standard fit. The hub material should have a yield strength sufficient to withstand the Ps radial contact pressure from the outer ring without plastic deformation.
What is the hub bore tolerance recommended for the TS7Z outer ring?
A hub bore tolerance of H7 is the standard recommendation. This provides a sliding clearance fit for the outer ring during installation, allowing the ring to be inserted and the clamping screws tightened without axial force. A tighter tolerance (H6) may be used if the hub bore machining permits, but should be confirmed against the specific TS7Z model’s outer diameter tolerance.
Source the TS7Z38×75 Locking Assembly
Ever Power manufactures the TS7Z38×75 and the complete TS7Z locking assembly series — 31 bore sizes from 15 mm to 110 mm — direct from our factory. Provide your shaft diameter, hub bore, application torque, and quantity for a prompt technical review and factory-direct pricing.