Descriptions of NKX 25 bearings

The needle roller bearing without inner ring is suitable for the parts of which the radial size is limited.
Because of no inner ring, the surface of shaft journal fitted with it is acted directly as rolling surface. It is requested that the surface hardness be no less than HRC60, surface roughness, no more than 0.63μm. This kind of bearing does not limit the axial shift of shaft and housing and has high limiting rotational speed.

The inner ring has no shoulder in this bearing. For this purpose, the inner ring, outer ring, complete set of needles and cage can be mounted respectively. This bearing does not limit the axial shift of shaft and outer housing. Since the cage separates the needles so as to reduce friction. It can be used for the parts with high rotational speed.

Needle bearings use a roller style rolling element to reduce friction of rotating surface and are more compact as the clearance has been reduced. Typically, the needle bearings consist of inner race, needle shaft, which orients the needle roller and an outer race. Needle bearings are primarily used in engine components, such as rocker arm pivots, pumps, compressors and transmissions.

Needle roller and cage type bearings use a roller style rolling element however, they do not include inside and outside races to maximize allotted space. Needle roller and cage type bearings have a larger surface area that is in contact with the bearing outer surface compared to traditional ball bearings. Typically, the needle roller bearings consist of needle cage, which orients and contains the needle rollers, and the needle rollers themselves. Needle roller and cage type bearings are predominantly used in engine components.

Drawn cup needle roller clutches have a small radial section height and are also commonly known as One Way Bearings or Anti-Reverse Bearings. This design uses the same small radial section as drawn cup needle roller bearings which make better use of available space. The units are compact, lightweight and operate directly on a shaft; they are also suitable for transmitting high torque.

One Way Bearings are designed to transmit torque between the shaft and housing in one direction and allow free motion in the opposite direction. Proper mounting is easily accomplished with a simple press fit in the housing. Clutches and clutch and bearing assemblies are offered both in inch and metric series. One Way Bearings without bearing assemblies are indicated by suffix: HF/FC/RC. One Way Bearings with bearing assemblies are indicated by suffix: HFL/FCB/RCB.

Specifications of  NKX 25 bearings

Classification and Characteristics of NKX 25 bearings 

SPECIAL NOTES

• HFL series has two integral radial bearings arranged on both sides of needle roller clutch. They can therefore support radial forces in particularly space-saving bearing arrangements. 
• Plastic springs (HFL...KF) are available for some sizes. 
• Partially knurled outer ring (HFL...R) is available upon request. 
• A special tool is suggested when assembling the clutch and bearing assembly. For details please contact our engineers. 
• Only after the clutch and bearing assembly has been pressed into the hole of the housing, the drawn thin-walled outer ring could then obtain its final dimension and geometric accuracy. 
• The transmissible torque and the stresses which can be taken by the housing are subject to the material and the wall thickness of the housing, and such data is needed upon enquiry. 
• The clutch and bearing assembly can be normally used in temperature range from -30°C to 120°C. For the working environment above 70°C, oil lubrication is recommended.

ONE WAY BEARING DESIGN FEATURES

• Torque can be transmitted by either the housing or the shaft.
• Torque is positively transmitted by rollers that wedge against interior ramps.
• Transition from free motion to lock occurs with minimal backlash or lost motion.
• Available as clutch-only or as a clutch and bearing assembly.
• Clutch-only units should be used with external radial support to hold the shaft and housing.

ONE WAY BEARING APPLICATIONS

• Paper moving for copiers, fax machines, paper towel dispensers, etc.
• Exercise equipment
• Appliances
• Two-speed gearboxes
• Rack indexing drives
• Converters, non-return devices and transcendental clutches. 
• Fishing Reels, RC Cars, RC Helis, RC Engines

INSPECTION OF ONE WAY BEARINGS

Although the outer cup of the clutch is accurately drawn from strip steel, it can go slightly out of round during heat treat. When the assembly is pressed into a ring gage or properly prepared housing of correct size and wall thickness, it becomes round and properly sized. Direct measurement of the outside diameter of a drawn cup assembly is an incorrect procedure. The proper inspection procedure is as follows:

1. Press the assembly into a ring gage of the proper size as given in the tabular data.
2. Gage the bore with the specified plug gages of the proper size, as given in the tables of dimensions.

- The locking plug is rotated to insure lockup when the clutch is operated at low limit shaft and is mounted in a high limit housing strong enough to properly size the clutch. 
- The overrun plug is rotated to ensure free over-running when the clutch is operated on a high limit shaft and is mounted in a low limit housing. 
- The go plug and no go plug insure proper size of the bearings in the clutch and bearing assemblies.

INSTALLATION OF ONE WAY BEARINGS

Simplicity of installation promotes additional cost savings. The drawn cup roller clutch, or the clutch and bearing assembly, must be pressed into its housing. The unit is pressed into the bore of a gear hub or pulley hub, or housing of the proper size, and no shoulders, splines, keys, screws or snap rings are required. Installation procedures are summarized in the following sketches:

Use an arbor press or hydraulic ram press which will exert steady pressure. Never use a hammer or other tool requiring pounding to drive the clutch into its housing.

Make sure that the housing bore is chamfered to permit easy introduction of the clutch and bearing or the clutch unit. Press unit slightly beyond the chamfer in the housing bore to assure full seating. Through-bored housings are always preferred. If the housing has a shoulder, never seat the clutch against the shoulder.

IMPORTANT: The mounted clutch or clutch and bearing assembly engages when the housing is rotated relative to the shaft in the direction of the arrow and LOCK marking stamped on the cup. Make sure that the unit is oriented properly before pressing it into its housing.

Use an installation tool as shown in the diagram below. If clutch is straddled by needle roller bearings, press units into position in proper sequence and preferably leave a small clearance between units. When assembling the shaft, it should be rotated in the overrun direction during insertion. The end of the shaft should have a large chamfer or rounding.

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Company Profile

Jinan Kelunte Bearing Co.,Ltd was established in 2010 which is located in Fenghuangshan Electricity Industrial Park,Tian Qiao Distirct,Jinan city.Our company is a modern enterprise which combines bearing marketing and production.Our factory covers an area of 10,000 square metres and our plant covers more than 5000 square meters.Our company initroduced our own brand CLUNT.Equiped with modern prodution equipment and advanced inspection equipment, our products are mainly for the high-end market.Our main products:pillow block bearings,deep groove ball bearings,taper roller bearings,linear bearings,cylinderical roller bearings,precision machine tool spindle bearings,spherical roller bearings,ect.Our products are widely used in autombiles,high presion motors,speed reducer,vibrating screen,crusher,railway,etc.

Jinan Kelunte Bearing Co.,Ltd takes specialization as core strategy,promoting internationalizion and diversification.Our company devotes to achive domestic and international advanced level.

Jinan Kelunte Bearing C.,Ltd has been a respected and excellet enterprise in bearing industry.We will keep moving forward.