Brand: Ringfeder

Ringfeder RfN 7007 Locking Assembly with Collar, 19-200 mm

Name: Ringfeder RfN 7007 Locking Assembly – Datasheet & Quote
Brand: Ringfeder
SKU: RfN 7007

Description

Two-piece locking assembly with a collar for axial positioning

The RfN 7007 is a two-piece, self-centering RINGFEDER locking assembly that RINGFEDER describes as similar to the RfN 7004. The product paper calls it a modification of the RfN 7004 that keeps all of its positive features but, like the RfN 7006, averts the axial displacement of the hub during mounting. A collar on the assembly fixes the hub axially during assembly and gives a high level of axial run-out accuracy, which is why the series suits exactly positioned parts such as impellers and thin-walled hubs with a short extension length.

As a keyless connection it transmits torque and axial force through friction: tightening the screws drives the taper rings together, clamping shaft and hub in one operation without a keyway. The tech paper covers shafts from 19 to 200 mm and torques from 320 Nm to 48,800 Nm.

Technical specifications

Parameter	Specification
Manufacturer	RINGFEDER POWER TRANSMISSION GmbH, Groß-Umstadt, Germany
Series	RINGFEDER RfN 7007 locking assembly, two-piece, self-centering, collar version of the RfN 7004
Shaft diameter d	19 to 200 mm
Outer diameter D	47 to 260 mm
Collar diameter DB1	53 to 259 mm
Transmissible torque T	320 Nm (19 x 47) to 48,800 Nm (200 x 260)
Axial force Fax	33 kN (19 x 47) to 488 kN (190 x 250 and 200 x 260)
Surface pressure	Shaft pW 100 to 180 N/mm2; hub pN 60 to 110 N/mm2 (tabulated sizes)
Locking screws	M6 to M14, 6 to 15 screws depending on size
Tightening torque TA	17 Nm (M6) to 230 Nm (M14)
Tolerances	Shaft h8, hub bore H8; surface finish Ra 1.6 um or better
Ordering example	RfN 7007 110 155 (d = 110 mm, D = 155 mm)

Selected sizes from the tech paper

d x D (mm)	Collar DB1 (mm)	L (mm)	L4 (mm)	T (Nm)	Fax (kN)	pW / pN (N/mm2)	Screws	TA (Nm)
19 x 47	53	45	31	320	33	180 / 70	6 x M6	17
30 x 55	61	45	31	500	33	115 / 60	6 x M6	17
40 x 65	71	45	31	890	44	110 / 70	8 x M6	17
50 x 80	86	55	36	2,020	81	145 / 90	8 x M8	41
60 x 90	96	55	36	2,430	81	120 / 80	8 x M8	41
80 x 120	126	72	46	5,230	131	110 / 70	8 x M10	83
100 x 145	151	89	52	9,780	196	115 / 80	8 x M12	83
120 x 165	171	89	52	14,660	244	115 / 85	10 x M12	145
150 x 200	206	98	59	30,340	405	140 / 105	12 x M14	230
200 x 260	259	98	59	48,800	488	130 / 100	15 x M14	230

L4 is the installation length up to the collar; the tech paper also tabulates the overall length without screws L1 and the ring width L3 (26 to 51 mm) for each size, and marks further sizes as available on request.

Where the 7007 differs from the 7004

Compared with the 7004 in the same d x D size, the RfN 7007 carries less torque but holds the pressure on shaft and hub lower. For a 50 x 80 assembly the 7004 lists 3,365 Nm with 240 / 150 N/mm2 on shaft and hub, while the 7007 lists 2,020 Nm with 145 / 90 N/mm2. RINGFEDER notes that the low surface pressure makes the series suitable for thin-walled hubs. Concentricity and easy dismantling carry over from the self-centering family, because the flange is reinforced at the critical point and prevents the inner ring lifting during installation. The assemblies remain true-to-form on mounting, so higher rotational speeds and high radial loads are within scope.

Fit and finish follow the tech paper: shaft h8, hub bore H8 and Ra 1.6 um on both. Confirm before ordering: torque with a shock factor, shaft and bore tolerances, hub wall thickness, the collar diameter DB1 against your hub design, and the available installation length L4.

Documents and quotation

The attached PDF is the RINGFEDER RfN 7007 tech paper (05.2024). Related locking devices are listed under Couplings & Shaft Locking Devices. Send shaft diameter, hub dimensions and torque for a size check.

Datasheets & Documents

Technical Data RINGFEDER RfN 7007 tech paper (EN, 05.2024) Download

Reviews (0)

Reviews

There are no reviews yet.

How would you rate this product?

About brand

RINGFEDER is a German maker of power transmission components and vehicle couplings, founded in 1922 in Krefeld to exploit patents for the ring spring, a friction spring first used in railway buffers. The same friction-ring principle later led to keyless locking devices and shrink discs. RINGFEDER POWER TRANSMISSION is part of the Swedish VBG Group, with its commercial office and R&D in Krefeld.

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 company profile

Founded	1922, Krefeld, Germany
Origin	Patent exploitation of the ring (friction) spring for railway buffers
Headquarters	Krefeld, Germany
Ownership	VBG Group, Vänersborg, Sweden
Acquisitions	TSCHAN shaft couplings (Neunkirchener Tschan GmbH)
Product families	Locking assemblies and shrink discs, TNM, TND and POSIMIX couplings, damping springs and friction springs, trailer couplings for trucks and agricultural vehicles

Milestones

1922: RINGFEDER is founded in Krefeld around the ring spring patent.
Later: The friction-ring principle is applied to keyless shaft-hub connections (locking assemblies and shrink discs).
Today: RINGFEDER operates within the VBG Group, with TSCHAN couplings added to its range.

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.

Ringfeder products we list

Family	Examples
Couplings & Shaft Locking Devices	RfN 4051 Light Shrink Disc, RfN 4061 Standard Shrink Disc, RfN 4091 Heavy-Duty Shrink Disc, RfN 7003 Self-Centring Locking Assembly, RfN 7005 Three-Piece Locking Assembly, RfN 7006 Locking Assembly with Collar, RfN 7012 Locking Assembly, RfN 7013.0 Self-Centring Locking Assembly and 5 more

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.

Facts checked against RINGFEDER catalogues, VBG Group information and German trade press, October 2026.

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

FAQ

Questions about the Ringfeder RfN 7007 Locking Assembly with Collar,

Answers from our engineering team on installation, compatibility and integration.

01How does the RfN 7007 relate to the RfN 7004?

The product paper calls it a modification of the RfN 7004 in which the axial displacement of the hub during mounting is averted.

02Which shaft diameters are covered?

19 to 200 mm, with 320 to 48,800 Nm in the tech paper.

03What is the collar for?

It fixes the hub axially during assembly and gives high axial run-out accuracy.

04Is it suitable for thin-walled hubs?

RINGFEDER states that its low surface pressure suits thin-walled hubs with a small extension length and exactly positioned impellers.

05Which tolerances are required?

Shaft h8 and hub bore H8, with surface finish Ra 1.6 um or better.