
4
Refer to chart below for hollow shaft inside dimensions and the recommended
load shaft dimensions.
Attach the load according to load shaft conditions as shown in either figure
above or below. The hollow shaft inside dimension is processed to a
tolerance of H8, and incorporates a key slot for load shaft attachment. A load
shaft tolerance of h7 is recommended. Apply a lubricant such as
molybdenum disulphide grease etc. to the load shaft and to the inner
circumference of the hollow shaft.
Hollow Shaft Inside Dimensions and Recommended Load Shaft Dimensions
After attaching the load, attach the safety cover.
Note • Do not apply excessive force when inserting the load shaft into the
gearhead. Excessive or abrupt force may damage the gearhead
internal bearings.
• When the hollow-shaft gearhead or solid-shaft gearhead with a
low gear ratio (5, 6, 7.5 or 9) is combined with a single-phase
motor, noise (resonance sound) may occur during operation
under no or light load. This noise can be reduced by adding a
frictional load.
Ø4.3
(Ø0.169)
Motor-gearhead assembly screws
(M4 hexagonal socket-head screws)
3. 3 Attaching Load
The shaft of the gearhead has been machined to an outer diameter tolerance
of h7 and is provided with a key slot for connecting the transmission parts.
When connecting the transmission parts, ensure that the shaft and parts
have a clearance fit, and secure with a screw to prevent the parts from
wobbling.
Note Do not use excessive force, or hammer the transmission parts onto the
gearmotor shaft as damage may occur.
3. 4 Disassembling the Motor and Gearhead (For only combination types)
In combination types, motor and gearhead are attached by means of
motor-gearhead assembly screws (hexagonal sockethead screws).
These screws must be removed in order to replace the gearhead.
Once the gearhead has been replaced, reassemble the unit using the screws
included with the gearhead for this purpose.
To install the unit in machinery, use the mounting screws, and follow the
instructions given in section 3. 1 ~ 3. 3.
The screw tightening torque for assembling motor and gearhead is shown in
the below chart.
•BH6G2-, BH8G-, BH6G2-RA
•BH6G2-RH (Hollow shaft type)
When the load shaft is stepped
Load Shaft
Hollow Shaft
Spacer
Flat Washer
Spring Washer
Groove for retaining ring
Screw (M6)
Hollow Shaft
Spacer
Flat Washer
Spring Washer
Groove for retaining ring
Screw (M6)
Spacer
Load Shaft
3. 2 Mounting the capacitor (For only single-phase motors)
Before mounting the provided capacitor, check that the capacitor’s capacitance matches that stated on the motor’s
name plate.
Use M4 screws to mount the capacitor (screws not provided).
∗Dimensions in millimeters (inches).
Note • Do not let the screw fastening torque exceed 1 N·m (8.85 lb-in) to prevent damage to the mounting feet.
• Mount capacitor at least 10 cm (3.94 in.) away from the motor. If it is located closer, the life of the capacitor
will be shortened.
When the load shaft is not stepped
Screw
∗Illustration shows parallel shaft type.
Motor Model Screw size∗1.0 N·m (8.85 lb-in)
10 N·m (88.5 lb-in)
BH6G2-,BH8G-
BH6G2-RH,BH6G2-RA
M4
M8
Tightening torque
∗The number of screws is two for BH6G2-and four with other models.
0
Gearhead Model
Hollow Shaft Inside Dimensions (H8)
Recommended Load Shaft Dimensions (h7)
BH6G2-RH
[Unit: mm(inch)]
Ø25 +0.033
Ø25
0
0(Ø0.9843 +0.0013)
(Ø0.9843
)
0
-
0.021
-
0.0008