№ 5 (86)
май, 2021 г.
32
A mechanism installed on a two-roll technological
machine, for example, on a machine for squeezing wet
leather, consisting of two working shafts 1 and 2 (Figure
2.1) on the surface of which tires 3 and 4 are put on,
where both working shafts have the ability to rotate
around their own axes O1 and О4 and move using levers
15, 16, 17 and 18, in a straight line passing through the
axes of rotation (О1 and О4) of the working shafts (1, 2)
consists of: driven and driving gears 5 and 6 rigidly
mounted at the output ends of the working shafts 1 and
2 and pivotally mounted levers 7 and 8, which are sup-
ports for axes 9 and 10. On axes 9 and 10, intermediate
gears 11 and 12 are installed. The axes of rotation of the
intermediate gears are kinematically interconnected by
a lever 13, which is located parallel to the line passing
along the axis of rotation of the working shafts 1, 2. The
lever 13 in its middle is rigidly fixed with the slider 14
at a right angle.
The mechanism works as follows: the torque from
the working shaft 1 to the working shaft 2 is transmitted
by means of the gear wheels of the drive 6, intermediate
11, 12 and driven 5. When the processed material with
variable thickness passes between the working shafts 1
and 2, the center distance О1О4 changes (Fig. .one). In
this case, the slider 14 provides the lever 13 (O2O3) with
a movement perpendicular to the line passing through
the axes of rotation (O1 and O4) of the working shafts 1
and 2. The system of levers and gear wheels provide
synchronous movement and rotation of the working
shafts 1 and 2, since the axes of rotation of the interme-
diate gears (O2 and O3 i.e. 9 and 10) will receive a rel-
ative speed equal in magnitude and parallel in direction,
and intermediate gears will receive angles of rotation
equal in magnitude and opposite in direction, thereby
compensating for the angles of rotation of each other.
Consequently, with a change in the center distance
O1O4, there is no difference in the angles of rotation of
the gear wheels of the driven 5 and the driving 6, and the
synchronization of rotation of these gears is ensured.
Since the gear wheels, driven 5 and driven 6, are rigidly
fixed at the output ends of the working shafts 1 and 2,
these working shafts will also rotate synchronously.
The kinematic analysis of the above-described
mechanism is carried out in order to determine the an-
gular and linear velocities and accelerations of the links
of the mechanism depending on the angular speed and
acceleration of the driving link (gear 5 or 6) and the lin-
ear speed and acceleration of the centers of rotation of
the driven links (gear 5 or 6), and also to prove the equal-
ity of the linear velocities of the surfaces of the working
shafts at the points of contact of these shafts with the
material being processed.
Figure 2.2 shows the design diagram of the kinemat-
ics of the mechanism under consideration, figure 2.3
shows the design diagram of the kinematics of the lever
contour of this mechanism.
In the considered mechanism, the diameters of the
driving and driven gears and parasitic gears are equal in
pairs or the diameters of all gears are equal to each other.
Thus, the transmission mechanism we are considering
are special cases of some generalized transmission
mechanism. Synchronous rotation of the driven and
driving gears (working shafts 1 and 2) at the time of
changing the center distance of the working shafts is per-
formed under the condition
1
4
d
d
=
,
2
3
d
d
=
(2.1)
or
1
4
2
3
d
d
d
d
d
=
=
=
=
(2.2)
and with a plane-parallel movement of the lever rel-
ative to the line passing through the points and (Figure
2.1).
1, 4 - driving and driven gear wheels; 2, 3 - intermediate gear wheels; 5, 6, 8, 9 - levers; 7 - slider.
Do'stlaringiz bilan baham: