Hofmann Snap-on Y2k Service Manual Download

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Remove a corresponding number of 0.2-mm thick washers from the main shaft, to get
a clearance between stator and brake disc of 0.5

+/- 0,1

mm.

Check that tie rod, clamping bolt and nut are sufficiently greased.
CAUTION! Use ball bearing grease Klüberplex BEM34-132 (HOFMANN Mat-Nr.
1317060).

k) Assemble all parts in reverse order and check the clearance.
l)

Switch on machine and check the function of the solenoid brake with code C73. Make
sure that the brake disc is fully clear of the stator when the brake current is switched
off. Otherwise, the unbalance result will be falsified.

m) Carry out adjustment of the unbalance measurement using codes C83 and C84.

If problems with the solenoid brake arise, exchange stator and brake disc at the same time.

15.6 The power-clamping device

The power-clamping device, moving the tie rod comprises of the following components:

a) The axially bored main shaft with the tapered end, the MZV-

adaptor is fitted on and

tightened axially by two hexagon screws (13 mm across the flats) to the to bayonet
disc.

b) The tie-rod with a spline shaft as part of it, so axial moveable in the bore of the main

shaft.
A short piece left-handed thread of 8-mm pitch is fitted spring loaded to the left-hand
end of the tie-rod.

c) The big pulley at the left-hand end of the main shaft supported by ball bearings.
d) The clamping nut of 8-mm pitch is flange-mounted to the big pulley with the thread of

the tie-rod engaged in it.

e) The incremental encoder B9 to determine tie rod travel and angular position of the

drive disc.

f) Solenoid brake Y2. The stator is fastened to the welded part and the brake disc to the

main shaft.

g) The pedal unit with two micro-switches S4 and S5 for actuating clamping action and

the main shaft lock.

The Power Interface board providing the following functions:

The high voltage brake driver with brake ammeter

The AC controller for various motor torque

The motor ammeter

Inputs for polling the pedal micro switches and the proximity detector.

Functioning of the power-clamping device

Once the clamping operation has been initiated, the solenoid brake Y2 is switched on and the
motion of the brake disk is monitored via incremental encoder B9. The brake locks the main
shaft. The motor M1 is switched on in the direction of rotation as during the measurement
run. The multi-vee belt conveys the motor torque to the big pulley and clamping nut. As the
tie rod cannot rotate inside the main shaft, the rotary motion of the clamping nut is converted
into longitudinal motion of the tie rod and later pulled to the left (max. travel is 76-mm). Via
the yoke with the two clamping jaws and the clamping sleeve, the motion is transferred to the
clamping head pulling the wheel on the cone and against the adaptor flange. With the wheel
pressed to the adaptor flange, longitudinal movement and the motor come to a stop. The stop
of the motion is detected via encoder B9. The drive and shortly afterwards the brake are
switched off.

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