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Freewheel Overrunning Clutch RIZ RINZ

The RIZ and RINZ series are centrifugal lift-off sprag type overrunning clutches with inner race rotation. Designed for high-speed overrunning, backstopping, and indexing, this overrunning clutch fully disengages as speed increases, minimizing friction and wear. Fully interchangeable with Stieber modular system units. Pre-greased, bearing-supported, and sealed for horizontal or vertical mounting.

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Product Detail

Freewheel Overrunning Clutch RIZ RINZ

Feature

Types RIZ, RINZ are centrifugal lift off sprag type freewheels with the inner race rotating. Suitable for backstop, or overrunning clutch applications. Only the inner race is designed for freewheeling.

These units are part of the Stieber modular system. They are bearing supported using series 60.. bearings, grease lubricated and fitted with ZZ seals. Units are delivered as standard lubricated with grease and ready to install in either a horizontal or vertical position. Types RIZ, RINZ are designed to be used with G series covers. The following pages give further inportant information for use of this type unit.

If the unit is to be installed inside a housing where oil lubrication is available, please specify type RIW, RIWN. The F series covers from type GFR, GFRN are then used without shaft seals.

Different types of Freewheel Overrunning Clutch RIZ RINZ

Type	Size		Speeds				Number				Weight
RIZ RINZ	d^H7	T_KN¹⁾	n_max²⁾	n_imin³⁾	n_imax⁴⁾	D_h7	z	L ₁	L	t
	[mm]	[Nm]	[min-1 ]	[min-1 ]	[min-1 ]	[mm]		[mm]	[mm]	[mm]	[kg]
	30	375	290	700	9000	100	6	68	43	10	2.3
	35	550	280	670	8500	110	6	74	45	12	3.2
	40	800	260	630	7500	125	6	86	53	14	4.8
	45	912	255	610	6700	130	8	86	53	14	5
	50	1400	235	560	6000	150	8	94	64	14	7.5
	60	2350	210	510	5300	170	10	114	78	16	12.7
	70	3050	195	470	4000	190	10	134	95	16	14.5
	80	5800	155	375	4000	210	10	144	100	16	19
	90	8700	145	350	3000	230	10	158	115	20	29.5
	100	16000	140	340	2400	270	10	182	120	24	42.5
	130	23000	130	320	2400	310	12	212	152	24	70

NOTES
1) T _max= 2 × T _KN
» Refer to Selection page 10 to 13
2) This maximum allowable torque transmission speed
n max must not be exceeded when transmitting torque
3) This minimum allowable overrunning speed n imin
should not be reduced under continuous operation.
Possible reduction of this minimum speed on request
4) Inner race overruns
Keyway to DIN 6885.1
» Refer to mounting and maintenance instructions
page 16 to 19

MOUNTING EXAMPLE

Typical Applications

High-Speed Overrunning – Inner race overrunning speed up to 9,000 min⁻¹ (size 30). Used in centrifuges, high-speed fans, textile machinery.

Backstopping – Prevents reverse rotation on inclined belt conveyors and bucket elevators during power loss or emergency stop.

Indexing – Provides precise positioning in packaging and printing machinery.

Product display

FAQs

Q1: What is the difference between RIZ and RINZ Freewheel Overrunning Clutch?

A: The main difference is overall length (L) and torque capacity. For the same bore size, RINZ has a longer body and higher torque rating. Check the parameter table or contact us with your specific model for confirmation.

Q2: Can Suma RIZ/RINZ directly replace Stieber units?

A: Yes. Our RIZ/RINZ series Freewheel Overrunning Clutches are designed to be fully interchangeable with Stieber modular system clutches. Mounting dimensions, torque, and speed ratings match. Send us your Stieber part number for cross-verification.

Q3: What if I need oil bath lubrication instead of grease?

A: Please specify the RIW/RIWN series. These units have no shaft seals and are designed for oil bath lubrication, used with GFR/GFRN covers.

Q4: Why is there a minimum overrunning speed (n imin)? What happens if I go below it?

A: Centrifugal lift-off clutches rely on speed to fully disengage the sprags. Below n imin, sprags do not lift off completely, causing continuous friction, temperature rise, and rapid wear. Prolonged operation below n imin will damage the clutch.

Q5: What is your price and lead time?

A: Suma is a factory direct overrunning clutch supplier. Standard sizes are typically in stock or 15-20 working days. Custom bores or special coatings require 25-30 days. Please provide your model, quantity, and any special requirements for a competitive quote.

Q6: Can RIZ/RINZ overrunning clutch be mounted vertically?

A: Yes. This series is pre-greased and sealed for both horizontal and vertical mounting. No additional modification is required.