Yanmar 3JH3E Service Manual page 123

Chapter 7 Reduction and Reversing Gear
_l_. _C_on_s_t_r_uc_t_io_n ____________________________
3,4JH3(B)(C)E
Marine Gear Models
KM3A
for Engine Models 3JH3BE
4JH3BE
1 . Construction
1
-1. Construction
This clutch is a cone-type, mechanically operated clutch.
When 1he drive cone (which is connected to the output
shaft by the lead spline}is moved forward or backward,
its taper contacts with the large gear and transfers power
to the output shaft.
The construction is simple when compared with other
types of clutch and if serves to reduce !he number of
components, making for a lighter, more compact unit
which can be operated smoothly. Although it is Small,
the power transmission efficiency is high even under
;;i
heavy load. Its durability is high and it is also reliable
because high grade materials are used for the shaft
and gear, and. a taper roller bearing is incorporated.
Power transmission is smooth because connection with
the engine is made through the damper disc.
• The drive cone is made from special aluminum
bronze which has both higher wear-resistance and
durability. The drive cone is connected with the
output shaft through the thread spline. The taper
c1ngle, diameter of the drive cone, twist angle, and
diameter of the thread spline, are designed to give the
greatest efficiency, thus ensuring that the drive cone
can be readily engaged or disengaged.
• Helical gears are used for greater strength.
The intermediate shaft is supported at 2 points to
reduce deflection and gear noise.
• The clutch case and mounting flange are made
from an aluminum alloy of special composition to
reduce weight.
Printed in Japan
lllNSIII-ll8009
7-1
It
is also anticorrosive against seawater.
• As the damper disc is fitted to the input shaft, power
can be transmitted smoothly.
• There is small clearance between the dipstick and the
inside of the dipstick tube. A small hole in the dip-
stick works as a breather.
• When the load on the propeller is removed, the
engagement of the drive cone and the large gear is
maintained by the shifter and V-groove of the drive
cone. Even when the drive cone's tapered area and
V-groove are worn, this engagement is maintained by
the shift lever device and accordingly no adjustment of
the remote control cable rs required.
• The cup spring on the rear of the larger gear absorbs
rotational fluctualions and stabilizes the engagement
of the drive cone and the larger gear. Thus, the
durability of the cone against wear is enhanced.