Brand: Ringfeder

Ringfeder RfN 7515 Three-Piece Locking Assembly, 60-640 mm

Name: Ringfeder RfN 7515 Locking Assembly – Datasheet & Quote
Brand: Ringfeder
SKU: RfN 7515

Description

Three-piece precision assembly for torque, axial force and bending

The RfN 7515 is a three-piece, self-centring precision locking assembly. RINGFEDER describes it as made for torque, axial force and especially bending loads, in joints with high requirements on the true running of the clamped parts. Long, flat cones carry the load and the relatively wide body gives excellent centring ability. During mounting the assembly and the hub move slightly in the axial direction. Shaft sizes run from 60 to 640 mm, with torque from 4,299 Nm to 1,300,152 Nm.

In the same product paper the RfN 7005 is the three-piece series aimed at the highest torques, while the RfN 7515 is the one to look at when bending moments and true running of the clamped parts are the main requirement.

Technical specifications

Parameter	Specification
Manufacturer	RINGFEDER POWER TRANSMISSION GmbH, Groß-Umstadt, Germany
Series	RINGFEDER RfN 7515 locking assembly, three-piece, self-centring precision type
Shaft diameter d	60 to 640 mm
Hub bore diameter D	95 to 735 mm
Overall length L	58 to 177 mm
Transmissible torque T	4,299 Nm (60 x 95) to 1,300,152 Nm (640 x 735)
Transmissible axial force Fax	143 kN to 4,063 kN
Surface pressure on shaft pW / hub pN	146 to 216 N/mm2 / 118 to 166 N/mm2
Locking screws	M8 x 40 to M22 x 130; 8 to 30 screws depending on size
Screw tightening torque TA	41 Nm to 930 Nm
Weight	1.5 kg to 112 kg
Surface finish	Shaft bore Ra 1.6 um or better, hub bore Ra 3.2 um or better
Tolerances	Shaft h8, hub H8
Ordering example	RfN 7515 150 200 (d = 150 mm, D = 200 mm)

Selected sizes from the tech paper

The table holds 37 sizes, with weights and minimum hub outside diameters for three yield strengths.

d x D (mm)	L (mm)	T (Nm)	Fax (kN)	Screws	TA (Nm)	Weight (kg)
60 x 95	58	4,299	143	9 x M8 x 40	41	1.5
80 x 120	70	10,399	260	10 x M10 x 50	83	2.7
100 x 145	82	18,881	378	10 x M12 x 60	145	4.3
150 x 200	91	42,483	566	15 x M12 x 70	145	7.1
200 x 260	116	92,880	929	18 x M14 x 80	230	15.4
300 x 375	131	263,085	1,754	16 x M20 x 90	690	30.6
400 x 495	177	595,903	2,980	22 x M22 x 130	930	72.7
640 x 735	177	1,300,152	4,063	30 x M22 x 130	930	112.0

Sizing notes

Hub outside diameter must satisfy DN min for the chosen steel. For 150 x 200 the table gives 319, 270 and 250 mm at Rp0.2 of 200, 300 and 400 N/mm2, calculated with factor C3 = 0.6. Weight of that size is 7.1 kg, and it carries 42,483 Nm and 566 kN with 15 M12 x 70 screws at 145 Nm. The largest size, 640 x 735, carries 1,300,152 Nm and 4,063 kN.

The tech paper values apply to oiled assemblies. A reduction of tightening torque lowers contact pressure and transmission values and should be agreed with RINGFEDER specialists; the same goes for combined bending and radial loads, for which the company asks you to contact its technical department. Shaft h8 and hub H8; the shaft bore needs Ra 1.6 um but the hub bore may be Ra 3.2 um. Confirm before ordering: bending moment, hub strength and outside diameter, and available length.

RINGFEDER also provides an online selection tool for locking assemblies. For hub and shaft stress, the calculation chapter of the product paper gives equations for thick-walled cylinders and a factor C3, which is 0.6 for one assembly in a hub at least twice the ring width long, 0.8 for two or more assemblies, and 1.0 where the hub length equals the ring width.

Documents and quotation

The PDF is the RINGFEDER tech paper for the RfN 7515 (05.2024). Related drive items are listed under Electric Motors and Gear Units. Send shaft diameter, loads and hub material for a size proposal.

Datasheets & Documents

Technical Data RINGFEDER RfN 7515 tech paper (EN, 05.2024) Download

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About brand

Ringfeder is a German manufacturer of shaft-hub connections and couplings for mechanical power transmission, headquartered in Groß-Umstadt and part of the Swedish VBG Group. Locking assemblies, shrink discs and locking elements are its core product groups.

Seven Star LLC is an independent supplier in Muscat. We list Ringfeder RfN series from the official tech papers and quote them for machine builders and maintenance teams in Oman and the GCC.

Ringfeder product series

Locking assemblies fit between shaft and hub bore: RfN 7012 for shafts from 19 to 1000 mm, the self-centring RfN 7013.0 and RfN 7003, the heavy torque RfN 7014, RfN 7015.0, the three-piece RfN 7005 and RfN 7515, RfN 7006 with collar, the miniature RfN 7061 and the compact RfN 7110. Shrink discs clamp a hollow hub onto a shaft from the outside: light RfN 4051, standard RfN 4061 and RfN 4071, mini RfN 4073, route-controlled RfN 4161 and heavy-duty RfN 4091 and RfN 4181. RfN 8006 locking elements cover shafts from 6 to 1000 mm.

All of these are keyless friction connections, so there is no keyway to weaken the shaft and no backlash. Each tech paper lists sizes, transmissible torque and axial force, screw tightening torques and tolerances.

Where Ringfeder connections are used

Gear wheels, sprockets, pulleys, couplings and brake discs on shafts; hollow-shaft gear units on conveyors, mills and crushers; and drives in mining, cement, wind energy and general machine building.

Ordering Ringfeder products: what we need

Give the RfN series and size, or the shaft diameter, hub bore and hub outside diameter, the torque and any axial or bending loads, and the material or surface finish required.

Browse Ringfeder products by category: Couplings & Shaft Locking Devices.