MJB-EGR
Flexible Coupling – Jaw – type (Bushing)
Dimension Drawing
Dimensions/Specifications/CAD
| Part Number | A | L | W | B | C | M | Number of bolts | M’ | Wrench Torque (N･m) |
|---|---|---|---|---|---|---|---|---|---|
| MJB-40-EGR | 40 | 25 | 66 | 12 | 2 | M4 | 6 | M4 | 4 |
| MJB-55-EGR | 55 | 30 | 78 | 14 | 2 | M5 | 4 | M5 | 8.5 |
| MJB-65-EGR | 65 | 35 | 90 | 15 | 2.5 | M5 | 8 | M5 | 8.5 |
| MJB-80-EGR | 80 | 45 | 114 | 18 | 3 | M6 | 8 | M6 | 14 |
| MJB-95-EGR | 95 | 50 | 126 | 20 | 3 | M8 | 8 | M8 | 35 |
| Part Number | Max. Bore Diameter (mm) | Rated Torque* (N・m) | Max. Torque* (N・m) | Max. Rotational (min-1) | Static Torsional Stiffness (N・m/rad) | Max. Lateral Misalignment (mm) | Max. Angular Misalignment (?) | Max. Axial Misalignment (mm) | Sleeve Hardness | Mass** (g) |
|---|---|---|---|---|---|---|---|---|---|---|
| MJB-40-EGR | 20 | 4.9 | 9.8 | 23000 | 380 | 0.15 | 1 | 0～+1.2 | A80 | 400 |
| MJB-55-EGR | 28 | 17 | 34 | 17000 | 1400 | 0.2 | 1 | 0～+1.4 | A80 | 800 |
| MJB-65-EGR | 38 | 46 | 92 | 14000 | 2800 | 0.2 | 1 | 0～+1.5 | A80 | 1100 |
| MJB-80-EGR | 45 | 95 | 190 | 11000 | 3200 | 0.2 | 1 | 0～+1.8 | A80 | 2300 |
| MJB-95-EGR | 50 | 130 | 260 | 10000 | 3600 | 0.2 | 1 | 0～+2.0 | A80 | 4000 |
* Correction of rated torque and max. torque due to load fluctuation is not required.
However, if ambient temperature exceeds 30?, be sure to correct the rated torque and max. torque with temperature correction factor shown in the following table. The allowable operating temperature of MJB is -20? to 60?.
** These are values with max. bore diameter
.
| Part Number | Stock Bores D1-D2 | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 8 | 9.525 | 10 | 11 | 12 | 14 | 15 | 16 | 18 | 19 | 20 | 22 | 24 | 25 | 28 | 30 | 32 | 35 | 38 | 40 | 42 | 45 | 48 | 50 | |
| MJB-40-EGR | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | – | – | – | – | – | – | – | – | – | – | – | – | – |
| MJB-55-EGR | – | – | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | – | – | – | – | – | – | – | – | – |
| MJB-65-EGR | – | – | – | – | – | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | – | – | – | – | – |
| MJB-80-EGR | – | – | – | – | – | – | – | – | – | – | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | – | – |
| MJB-95-EGR | – | – | – | – | – | – | – | – | – | – | – | – | – | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
All products are provided with hex socket head cap screw.
Recommended dimensional allowances of applicable shaft diameter are h6 and h7.
Material/Finish
| MJB | |
|---|---|
| Hub | S45C Ferrosoferric oxide film |
| Outer ring | S45C Ferrosoferric oxide film |
| Sleeve | Polyurethane |
| Hex Socket Head Cap Screw | SCM435 Ferrosoferric oxide film |
Structure
Bushing type
MJB >> MJB-BL , MJB-GR , MJB-RD , MJB-WH , MJB-EBL , MJB-EGR , MJB-ERD , MJB-EWH
Characteristics
- Applicable motors
Tight fit Easy Fit Servomotor ◎ ○ Stepping Motor ◎ ◎ General-purpose motor ◎ ◎ ?: Excellent : Very good
- Property
Tight fit Easy Fit High torque ◎ ◎ Allowable Misalignment ○ ○ Vibration absorption ◎ ◎ Electrical insulation ◎ ◎ Assembling ○ ◎ Allowable operating temperature -20℃ to 60℃ -20℃ to 60℃ ?: Excellent : Very good
- This is a jaw type flexible coupling.
- This superior high torque transmission is the most appropriate for the spindle of a machine tool.
- Excellent flexibility allows eccentricity, and angular misalignment and vibration to be accepted.
- It has electrical insulation. Resistance value: not less than 2 M?.
- There are four types of sleeve hardness. Please select desirable units according to usage conditions including torque and misalignment.
- Since the sleeve’s vibration absorption can raise the gain of a servomotor, tight fit can achieve high responsive operation exceeding the Disk coupling.
- Easy fit allows you to assemble and partition the hub and sleeve smoothly. This allows you to reduce the time of assembling the unit and maintenance.
- Sleeve type
Application
Machine tool / Spindle
Selection
The area bounded by the shaft diameter and rated torque indicates is the selection size.
Selection example
In case of selected parameters of shaft diameter of ? 18 and load torque of 16 N•m, the selection size for MJB-**-BL,MJB-**-EBL is MJB-55-BL,MJB-55-EBL
Ambient Temperature / Temperature Correction Factor
| Ambient temperature | Temperature correction factor |
|---|---|
| -20℃ to 30℃ | 1.00 |
| 30℃ to 40℃ | 0.80 |
| 40℃ to 60℃ | 0.70 |
Sleeve Details
Mounting / Removing
Mounting
1.Clean up the fitting surfaces of hub, outer ring and shaft.
2.Apply light oil thinly on the surfaces. Avoid molybdenum base oil as it reduces the fastening power seriously.
3.Insert the shaft to the dimension L.?Table 1
4.Tighten the hexagon socket head bolts with 50% of the tightening torque inTable 1, each for once, following the sequence in Fig.1
5.In the same sequence as in?, tighten the hexagon socket head bolts with 100% of the tightening torque inTable 1, each for once.
6.Tighten all hexagon socket head bolts with the tightening torque inTable 1, following the sequence in Fig.2
7.Repeat ?until all hexagon socket head bolts get securely fixed.
As a guide, the rotation of a hexagon socket head screw, when tightened, should be less than 20 degrees.
Table 1
| Part Number | L | Hex Socket Head Cap Screw | Screw Tightening Torque（N・m） | |
|---|---|---|---|---|
| Diameter of Thread | Number of bolts | |||
| MJB-40 | 25 | M4 | 6 | 4 |
| MJB-55 | 30 | M5 | 4 | 8.5 |
| MJB-65 | 35 | M5 | 8 | 8.5 |
| MJB-80 | 45 | M6 | 8 | 14 |
| MJB-95 | 50 | M8 | 8 | 35 |
Removal
1.Disassemble the hub and the sleeve.
2.Confirm that there is no torque or thrust load, then loosen all hexagon socket head bolts completely and remove them.
3.Insert one of the removed bolts in ?to a forcing tap, and tighten little by little, avoiding uneven clamping.
4.Repeating 3.makes the tightening torque will get very small. Remove the coupling from the shaft, as the fastening force from the tapered surface is reduced.
!!! Use a torque wrench to tighten bolts.
Slip Torque
Concerning the sizes shown in the following table, please note that the shaft’s slip torque is smaller than the max. torque of MJB .
| Part Number | Bore（mm） | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 10 | 11 | 12 | 14 | 15 | 16 | 18 | 19 | 20 | 22 | 24 | 25 | 28 | 30 | 32 | 35 | 38 | 40 | 42 | 45 | 48 | 50 | |
| MJB-55 | 32.8 | 54 | 75.2 | 117 | 138 | |||||||||||||||||
| MJB-65 | 161 | 171 | 181 | 202 | 212 | 222 | 243 | 264 | 274 | 305 | 325 | 346 | 377 | |||||||||
| MJB-80 | 285 | 335 | 385 | 411 | 486 | 500 | 500 | 500 | 500 | 500 | 500 | 500 | ||||||||||
| MJB-95 | 500 | 500 | 500 | 500 | 500 | 500 | 500 | 500 | 500 | 500 | 500 | |||||||||||
These are test values based on the condition of shaft’s dimensional allowance: h7, hardness: 34 – 40 HRC, and screw tightening torque of the values described in MJB Dimension table.
Change in static torsional stiffness due to temperature
This is a value under the condition where the static torsional stiffness at 20?C is 100%.
The change of torsional stiffness within the range of allowable operating temperature is as shown in the graph.
Before using the unit, be aware of the deterioration of responsiveness.
Eccentric Reaction Force
