Mitsubishi Electric RH-FRH Series Instruction Manual page 128

5 Maintenance and Inspection
6) Remove the timing belt <4> from the top of the shaft
If using the optional hand internal wiring and piping set, temporarily remove the hand input cable connector
<11> and air hoses <12> of solenoid valve side. And remove the timing belt to upward.
7) Install the new timing belt in reverse procedure of removal.
Install the new belt to the timing pulley (on the motor) <5> and timing pulley B <6> securely.
Fix the shaft fixing plate <8> by fastening the original fixing screws securely.
If using the hand input cables <11> and air hoses <12>, connect them as before.
8) Install the J3 axis motor <3> by tightening lightly the J3 axis motor fixing screw <2> (two screws)
9) The nut which is fixing tension adjustment screw <1> is loosened, turn tension adjustment screw <1>, and
adjust the tension of timing belt <4>.
When the screw is turned to the right, the belt will be stretched, and when turned to the left, will loosen.
Adjust the belt tension slack to within the range as shown in
Before the tension measurement, rotate the timing pulley at least three times in each direction so that the
timing belt fits in the pulley. Check the tension measurement method in
measurement".
If the belt is loosened too much when adjusting the tension causing it to come off the timing pulley A <5> and
the timing pulley B <6>, or if the belt and pulley teeth engagement is deviated, the machine system's origin will
deviate.
10) Fasten the two J3 axis motor fixing screws <2> certainly (M4 screw: tightening torque is 4.51 Nm). Moreover,
also fasten the nut of tension adjustment screw <1> certainly. Improper tightening can cause the belt to loosen
with vibration.
11) Install the No.2 arm cover U securely as before.
12) Reset the origin of J3 and J4 axis with referring to the
13) When the maintenance forecast function is valid, reset the accumulation data about the belt. Reset by the
dedicated screen or parameter MFBRST of RT ToolBox3. Refer to "RT ToolBox3/RT ToolBox3 mini User's
Manual" for operation of RT3 and refer to "Instruction Manual/Detailed Explanation of Functions and
Operations" for the parameter.
Replacement of the J3 axis timing belt is completed.
Maintenance and inspection procedures
5-115
Remove to upward
<4> Timing belt
Page 125, "(12) Timing belt
Page 111, "(2) Timing belt tension
Page 142, "5.6 Resetting the origin"
<11> Hand input cable con -
nector
Remove temporarily
<12> Air hoses
Remove temporarily
tension".