When "FINE U-NUT" is screwed onto a shaft, the friction ring comes into contact with the shaft thread. As the nut is tightened further, the friction ring begins to bend along with the screw thread and presses against the shaft screw threads.A spring effect produced by the friction ring (P), along with a reactionary force that pushes against the screw flank surface (P'), generates prevailing torque (frictional torque) and demonstrates the locking function.
FINE U-NUT
A locknut for use with bearings
Features
- Reusability:
Can be reused - Simple fastening:
Fine adjustment is possible from any position, and torque management is easy - Labor saving and simplified assembly:
Eliminates the need for toothed lock washers and the keyway machining of shafts - Balance:
Improves rotational balance of the shaft - Weight reduction:
Allows for the use of hollow shafts that are thinner than normal - Cost reduction:
Achieves a total cost reduction by eliminating the need for processing, parts, and technology that were previously required - Dedicated tools in a range of sizes, from M10 to M100, are available
General names
Bearing nut, Shaft locknut, Adapter nut, Grooved round nut
Video of features
Applicable markets
- Two-wheeled vehicles
- Four-wheeled vehicles
- Special-equipped vehicles
- Farm equipment
- Conveyers
- Railways
- Marine vessels
- Plants
- Machine tools
- Industrial equipment
- Electronics
- Medical care and welfare
- Infrastructure
- Civil engineering
- Architecture
- Playground equipment
Structure & Function
Structure description video
The FINE U-NUT vs. Conventional Product
FINE U-NUT
- Consists of 3 basic parts.
- Just insert to fasten.
Conventional product
- Consists of 4 basic parts.
- A toothed lock washer and keyway machining are required.
Basic Information
Specs
| Steel friction ring | 270°ring |
|---|---|
| Thread accuracy | JIS6H (JIS Class 2) Face runout (maximum): 0.05 mm (M8 to M50) Face runout (maximum): 0.07 mm (M55 to M120) Face runout (maximum): 0.10 mm (M125 to M150) |
| Sizes | M 8 to M100 (SS Series) M10 to M150 (SC Series) M10 to M100 (SUS Series) *Pitch: Fine thread |
| Shapes | Grooved round nut *Other special shapes |
| Materials | SS400 or equivalent, S45C (thermal refined), SUS304 or equivalent |
Dimensional Charts
FINE U-NUT Dimensional Chart
Thread Accuracy: JIS6H(Class 2) Unit:mm
| Part No. | Designation of Thread (d×p) |
Flange Diameter (φd1) |
Outside Diameter (φd2) |
Overall Height (h) |
Thread Height (m) Approx. |
Width of locknut slot (b) |
Depth of locknut slot (h1) Approx. |
Locknut slot opposite side (g) |
Maximum face runout (max) |
Thread accuracy length ℓmin |
Unit Weight (g) Approx. |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SC Series (S45C-H) |
SS Series (SS400) |
SUS Series (SUS304) |
||||||||||||||||
| ― | FUNM8SS | ― | M 8×0.75 | 12.0 | 0 -0.5 |
16 | 0 -0.5 |
5.3 | ±0.3 | 4.3 | 3 | ±0.2 | 1.5 | 13.0 | 0 -0.5 |
0.05 | 5.8 | 4.1 |
| FUN00SC | FUN00SS | FUN00SUS | M10×0.75 | 13.5 | 18 | 5.2 | 4.0 | 3 | 1.8 | 14.4 | 5.5 | 4.5 | ||||||
| FUN01SC | FUN01SS | FUN01SUS | M12×1 | 17.0 | 22 | 5.4 | 4.0 | 3 | 1.8 | 18.4 | 6.0 | 8.0 | ||||||
| FUN02SC | FUN02SS | FUN02SUS | M15×1 | 21.0 | 25 | 6.5 | ±0.5 | 5.0 | 4 | 1.8 | 21.4 | 7.0 | 12.0 | |||||
| FUN03SC | FUN03SS | FUN03SUS | M17×1 | 24.0 | 28 | 6.4 | 5.0 | 4 | 1.9 | 24.2 | 7.0 | 13.0 | ||||||
| FUN04SC | FUN04SS | FUN04SUS | M20×1 | 26.0 | 32 | 7.7 | 6.0 | 4 | 1.8 | 28.4 | 8.0 | 23.0 | ||||||
| FUN05SC | FUN05SS | FUN05SUS | M25×1.5 | 32.0 | 38 | 9.1 | 7.0 | 5 | 2.0 | 34.0 | 10.0 | 36.0 | ||||||
| FUN06SC | FUN06SS | FUN06SUS | M30×1.5 | 38.0 | 45 | 9.1 | ±0.8 | 7.0 | 5 | 2.0 | 41.0 | 10.0 | 45.0 | |||||
| FUN07SC | FUN07SS | FUN07SUS | M35×1.5 | 44.0 | 52 | 10.2 | 8.0 | 5 | 2.0 | 48.0 | 11.0 | 70.0 | ||||||
| FUN08SC | FUN08SS | FUN08SUS | M40×1.5 | 50.0 | 58 | 11.2 | 9.0 | 6 | 2.5 | 53.0 | 12.0 | 95.0 | ||||||
| FUN09SC | FUN09SS | FUN09SUS | M45×1.5 | 56.0 | 65 | 12.5 | ±1.0 | 10.0 | 6 | 2.5 | 60.0 | 13.0 | 130.0 | |||||
| FUN10SC | FUN10SS | FUN10SUS | M50×1.5 | 61.0 | 70 | 13.5 | 11.0 | 6 | 2.5 | 65.0 | 14.0 | 160.0 | ||||||
| FUN11SC | FUN11SS | FUN11SUS | M55×2 | 67.0 | 75 | 13.5 | 11.0 | 7 | 3.0 | 69.0 | 0.07 | 15.0 | 185.0 | |||||
| FUN12SC | FUN12SS | FUN12SUS | M60×2 | 73.0 | 80 | 13.5 | 11.0 | 7 | 3.0 | 74.0 | 15.0 | 190.0 | ||||||
| FUN13SC | FUN13SS | FUN13SUS | M65×2 | 79.0 | 85 | 15.0 | ±1.5 | 12.0 | 7 | 3.0 | 79.0 | 16.0 | 235.0 | |||||
| FUN14SC | FUN14SS | FUN14SUS | M70×2 | 85.0 | 92 | 15.0 | 12.0 | 8 | 3.5 | 85.0 | 16.0 | 265.0 | ||||||
| FUN15SC | FUN15SS | FUN15SUS | M75×2 | 90.0 | 98 | 15.8 | 13.0 | 8 | 3.5 | 91.0 | 17.0 | 320.0 | ||||||
| FUN16SC | FUN16SS | FUN16SUS | M80×2 | 95.0 | 105 | 18.6 | 15.0 | 8 | 3.5 | 98.0 | 19.0 | 430.0 | ||||||
| FUN17SC | FUN17SS | FUN17SUS | M85×2 | 102.0 | 0 -0.75 |
110 | 19.2 | 16.0 | 8 | ±0.3 | 3.5 | 103.0 | 20.0 | 495.0 | ||||
| FUN18SC | FUN18SS | FUN18SUS | M90×2 | 108.0 | 120 | 20.3 | 16.0 | 10 | 4.0 | 112.0 | 20.0 | 630.0 | ||||||
| FUN19SC | FUN19SS | FUN19SUS | M95×2 | 113.0 | 125 | 21.3 | 17.0 | 10 | 4.0 | 117.0 | 21.0 | 725.0 | ||||||
| FUN20SC | FUN20SS | FUN20SUS | M100×2 | 120.0 | 130 | 22.3 | 18 | 10 | 4.0 | 122.0 | 22.0 | 770.0 | ||||||
| FUN21SC | ― | ― | M105×2 | 126.0 | 140 | 22.3 | 18.0 | 12 | 5.0 | 130.0 | 22.0 | 904.0 | ||||||
| FUN22SC | ― | ― | M110×2 | 133.0 | 145 | 23.3 | 19.0 | 12 | 5.0 | 135.0 | 23.0 | 954.0 | ||||||
| FUN23SC | ― | ― | M115×2 | 137.0 | 150 | 23.3 | 19.0 | 12 | 5.0 | 140.0 | 23.0 | 1,030.0 | ||||||
| FUN24SC | ― | ― | M120×2 | 138.0 | 155 | 24.3 | 20.0 | 12 | 5.0 | 145.0 | 24.0 | 1,080.0 | ||||||
| FUN25SC | ― | ― | M125×2 | 148.0 | 160 | 25.4 | 21.0 | 12 | 5.0 | 150.0 | 0.1 | 25.0 | 1,170.0 | |||||
| FUN26SC | ― | ― | M130×2 | 149.0 | 165 | 25.4 | ±2.0 | 21.0 | 12 | 5.0 | 155.0 | 25.0 | 1,250.0 | |||||
| FUN27SC | ― | ― | M135×2 | 160.0 | 175 | 26.6 | 22.0 | 14 | 6.0 | 163.0 | 26.0 | 1,586.0 | ||||||
| FUN28SC | ― | ― | M140×2 | 160.0 | 180 | 26.6 | 22.0 | 14 | 6.0 | 168.0 | 26.0 | 1,748.0 | ||||||
| FUN29SC | ― | ― | M145×2 | 171.0 | 190 | 28.6 | 24.0 | 14 | 6.0 | 178.0 | 28.0 | 2,000.0 | ||||||
| FUN30SC | ― | ― | M150×2 | 171.0 | 195 | 28.3 | 24.0 | 14 | 6.0 | 183.0 | 28.0 | 2,050.0 | ||||||
Please feel free to contact us for sizes, shapes, and materials that are not listed.
Prevailing Torque
Performance of the prevailing torque and reusability
Prevailing torque is produced by the spring effect when the friction ring touches the bolt threads.
Sample
| FUN04SC M20×1 | |||
|---|---|---|---|
| Maximum Installation torque | Minimum removal torque | ||
| 1cycle | 10cycle | 1cycle | 10cycle |
| 4.7 | 3.5 | 4.3 | 3.3 |
Even re-used 10 times, the prevailing torque shows only a slight decrease.
Test Condition
| Bolt material | SCM435H |
|---|---|
| Thread accuracy | JIS 6g |
| Surface treatment | plain (nut and bolt) |
| Lubricant | penetrating lubricant |
Tests
Axial vibration impact test
In this test, bolts and nuts fastened to a vibration barrel are subjected to repeated impacts in the axial direction of the bolt, and the presence or absence of loosening is examined to determine the anti-loosening performance.Test Condition
| Sample Size | M20×1 |
|---|---|
| Tightening Torque | 53.9N･m｛550kg･cm｝ |
Testing machine specifications
| Frequency | 1,278c.p.m. |
|---|---|
| Excitation stroke | 11mm |
| Impact stroke | 10mm |
| Vibration acceleration of the excitation table |
10G |
| Excitation time | 60 min. |
| Direction of impact | Bolt axial direction |
Test Result
Rotational Life Test
In this test, after fastening a nut to the main shaft of a rotating durability tester, acceleration and stopping are repeated, and inertial force is applied to the nut to check for loosening and determine the locking performance.Test Condition
| Sample aize | M55×2 |
|---|---|
| Number of rotations | 2,300rpm |
| Testing cycles | 1 cycle(forward・stop・reverse・stop) 10 sec. |
| Stopping time | When forward・0.30sec When reverse・0.27sec |
Inertial Force to The Nut when It Stops
| Sample | Inertial force N･m {kgf･cm} | |
|---|---|---|
| forward | reverse | |
| Commercial nut | 0.14｛1.42｝ | 0.15｛1.57｝ |
| FINE U-NUT | 0.15｛1.52｝ | 0.17｛1.69｝ |
Test Result
| Sample | Sample No. |
Test result |
|---|---|---|
| Commercial nut ＋ toothed lock washer |
1 | Washer damaged and nut came off at approx. 110,000 cycles |
| 2 | Washer damaged and nut came off at approx. 330,000 cycles | |
| FINE U-NUT | 3 | No change after 500,000 cycles |
| 4 |
Installation Instructions
-
Thread the bearing through the shaft thread. Check that the tip of the shaft thread has been chamfered (C = 1 pitch or equivalent) before applying lubricant. If the hardness of the shaft thread is low, use a lubricant with especially high lubricating performance.
-
Manually screw the nut on until the friction ring touches the tip of thread portion of the shaft.
-
Use a tightening tool made especially for the FINE U-NUT.
*An impact wrench cannot be used. -
Push down on the axis portion of the ratchet handle and gently turn the ratchet to tighten.
*The nut cannot be screwed on from the friction ring side. -
Check that the inner ring of the bearing is in complete contact with the seat surface of the FINE U-NUT, and that at least two full shaft threads come out of the friction ring.
When removing the nut, use a tightening tool to unscrew it until the friction ring is separated from the tip of the threaded portion of the shaft. -
*A hook wrench can also used to remove the nut.
-
-
Precautions for Use
This product is used for fastening parts that are especially important.
Please observe the following rules when using this product.
-
Clean the threaded portion of the shaft when screwing on or unscrewing the nut.
-
A thread accuracy of ISO6g is recommended for the shaft thread.
Chamfer (C = 1 pitch or equivalent) the tip of the threaded portion of the shaft. -
Be sure that there are no burrs or dents on the chamfer or threaded portion of the shaft.
-
Use lubricant when screwing on or unscrewing the nut. (If there is a risk that chipping may occur, use a lubricant with especially high lubricating performance. )
-
To fully demonstrate the locking function of the FINE U-NUT, make sure that at least two full bolt threads come out of the friction ring.
*Refer to the dimensional chart for extra shaft thread dimensions. -
To prevent the nut from hitting one side, it is necessary to tighten the nut by about twice the prevailing torque or more.
*Please contact us about prevailing torque. -
The nut cannot be used if the threaded portion of the shaft is machined (keyway, etc.).
*If you are using a shaft with a keyway, etc., please consult with us. -
An impact wrench cannot be used.
-
The nut cannot be screwed on from the friction ring side.
-
Stop using the FUJILOK U-NUT if abnormal deformation or other faults occur on the friction ring and clamp.
-
Consult us before using the FUJILOK U-NUT under severe conditions or with low axial force.