Description
TS7Z24×55 Locking Assembly – 24mm Shaft 55mm OD Keyless Rigid Shaft-Hub Connector
At 24 mm bore and 55 mm OD, the TS7Z24×55 covers mid-range motor shafts in the 1–3 kW power class. The 0.302 kN·m torque rating and 25.2 kN axial capacity make it suitable for direct coupling of IEC frame 112 motors to driven equipment hubs without shaft modification. 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 — 95 MPa for the TS7Z24×55 at the specified M_a of 17 N·m — generates a friction connection that transmits both torque (Mt = 0.302 kN·m) and axial force (Ft = 25.2 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 | TS7Z24×55 |
| Type | Locking Assembly (Keyless Shaft-Hub Connection) |
| Shaft Bore (d) | 24 mm |
| Outer Diameter (D) | 55 mm |
| Rated Axial Force (Ft) | 25.2 kN |
| Rated Torque (Mt) | 0.302 kN·m |
| Surface Pressure (Ps) | 95 MPa |
| Installation Screw Torque (Ma) | 17 N·m |
| Mass (G) | 0.73 kg |
| Material | Steel |
| Standard | GB/T 5106 compatible |
Dimensional Reference
Structural Cross-Section
Installation and Design Guidance
Installation of the TS7Z24×55 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 = 17 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 (95 MPa) ≤ 0.9 × shaft yield strength. For C45 steel (yield ~370 MPa): 0.9 × 370 = 333 MPa > 95 MPa — acceptable. For aluminium alloy 6061-T6 (yield ~275 MPa): 0.9 × 275 = 247 MPa; compare with 95 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
★★★★★
Belgium — Industrial Fan Manufacturing
Used in industrial fan impeller hub connections in our power station forced-draft fan installations. The TS7Z24×55’s even radial preload distribution minimises hub distortion under the fan’s rotor dynamic loading, which is important for maintaining the dynamic balance quality of the assembled fan rotor.
— Technical Manager, Ghent
★★★★★
Argentina — Pump & Compressor OEM
Installed on compressor crankshaft to flywheel connections on our reciprocating gas compressors. The locking assembly’s keyless connection distributes torque through friction over the full bore surface rather than concentrating load at a key, which our fatigue analysis showed extended shaft service life by an estimated 40% under our operating cycle.
— Engineering Manager, Buenos Aires
★★★★☆
Chile — Sugar Mill Engineering
The TS7Z24×55 is used in cane crusher roll drive connections at our sugar milling facility. The locking assembly handles the high sustained torque and occasional shock loading of cane crushing without slip or fretting. The keyless design allows roll removal during the crushing season’s maintenance shutdowns without shaft re-machining.
— Senior Engineer, Santiago
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.
Does the TS7Z locking assembly require a keyway in the shaft?
No. This is a primary advantage of the locking assembly design. The shaft requires only a plain, ground cylindrical surface within the bore tolerance — no keyway machining is required. This eliminates the keyway stress concentration and simplifies shaft manufacturing.
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 is the Ps (surface pressure) parameter and how is it used?
Ps is the radial contact pressure between the inner ring and the shaft surface at the specified installation torque. It is used to verify that the shaft material’s yield strength is not exceeded. The design rule is: Ps must be less than 0.9 × yield strength of the shaft material. For mild steel shafts (yield ~250 MPa), Ps must be below 225 MPa.
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.
Source the TS7Z24×55 Locking Assembly
Ever Power manufactures the TS7Z24×55 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.