Basic informationsBasic informationsVariators in the basic design solve all requirements for infinitely variable gears from 0.85 to 21 kW outputs, with control range up to max. 1:6 and with optional output speed. All this is achieved by a purposeful division of the variable speed gearbox sizes and by a suitable connection with countershafts of unit-construction design on input and output sides.
Variable speed gear-boxes hold the speed at an optional value even at a variable load, as the power transmission is without slip. The advantage of these machines is the minimum requirements for space.
The output of the basic variable speed gear-box may be increased up to 55 kW by connecting a differential countershaft on the variable speed gear-box input side with the simultaneous reduction of the control range.
The output speed range may be increased, further, by connecting a satellite or movable layshaft on the variable speed gear-box output side.
Basic elements of the infinitely variable speed change variable by the speed gear-boxes are two pairs of conical grooved disks and a plate-link chain. Grooved disks are fitted on driving and driven shafts and are axially movable on the same. Between these two pairs of disks there is directed and endless platelink chain which connects both pairs of disks - it changes the rotary motion of driving disks to the rectilinear one and on driven disks to the rotary motion again. The endless plate-link chain consists of a number of links which are mutually connected with pins; crosswise slidable plates are arranged inside the links.
The gear ratio may be changed so that disks of one pair are forced together, disks of the other pair are removed in dependence upon the first pair. In the pair of disks forced to each other, the chain gets moved to a larger diameter, in the opposite pair of disks, it gets moved to a smaller diameter. The required gear ratio is set up by means of two-armed levers being pivoted on a centric bolt.
The values of outputs and torques stated in the tables apply to a normal single-shift operation and for not too frequent starting. In case of other operating conditions, an equivalent output must be ascertained for the determination of the variable speed gear-box size. To this effect the coefficients stated in the following table should be applied:
| Operating conditions | Coefficient | ||
|---|---|---|---|
| Number of
starts in a hour |
10 | 1 | ks |
| above 10 | 1,3 | ||
| Number of operating hours |
up to 8 | 1 | kh |
| from 8 up 16 | 1,3 | ||
| from 16 up 24 | 1,5 | ||
| Character of load |
permanent | 1 | kz |
| intermittent | 1,3 | ||
| impact | 1,5 | ||
Example:
The determination of the variable speed gear-box size for driving a machine
with following requirements:
| Infinitely variable speed control within ............... | 420-1250 | |
| Output Ns | at nmin ........................... | approx. 0,75kW |
| at nmax .......................... | approx. 1kW | |
| Number of startings ..................................... | up to 10/hour | |
| Character of operation ................................. | continuous | |
| Load .................................................... | impact | |
Determination of equivalent output:
| Nmin | = Ns x ks x kh x kz |
| = 0,75 x 1 x 1,5 x 1,5 | |
| = 1,68 kW | |
| Nmax | = Ns x ks x kh x kz |
| = 1 x 1 x 1,5 x 1,5 | |
| = 2,25 kW |
On the basis of calculated values, there should be chosen "2" variable speed gear-box with following values according to tables:
| Driving speed | n | = 720 r.p.m. |
| Output speed | nmin | = 415 r.p.m. |
| nmax | = 1245 r.p.m. | |
| Output | Nmin | = 1,9 kW |
| Nmax | = 2,6 kW |
The control range of the variable speed gear-box is understood the ratio of the minimum and maximum output speeds. The maximum control range variable speed gear-boxes is 1:6.
Typified control ranges with which the variable speed gear-boxes are currently delivered rate 1:3, 1:4.5 and 1:6. Upon the buyer's wish, the variable speed gear-box may be adjusted for any control range up to 1:6.
The upper limit recommended for the variable speed gear-box output shaft speed is 1800 r.p.m. and the recommended lower limit is 200 r.p.m.
The typified variable speed gear-boxes (with driving speeds specified in tables)
includes the optimum number of gear ratio kinds mutually tuned up with output.
The values of output and torques are stated with respect to the efficiency of
gears on the countershaft.
Every basic variable speed gear-box type has several variants according to the
selected control way and position of the control system, according to the arrangement
of input and output shafts and according to the cover position in vertical variable
speed gear-boxes.
The shaft ends are designed according to the ISO. Standards at k7 and provided with tapped pits according to Czechoslovak State Standard LSN 01 4917. Keys according to Czechoslovak State Standard ESN 02 2562. The axial height of shafts is within
tolerance of ± 1/600 H
The indicator and the control wheel must be situated on the same side of the variable speed gear-box. In the place of the control wheel there may be used the mechanical or electrical remote control.
The upper cover may be on A or B sides.
The variable speed gear-box should be situated so that the upper cover may be accessible for the reason of adjusting the variable speed gear-box or replacing the chain and oil. The mentioned oil quantity and mass are average values. A part view of the control part of the variable speed gear-box shows the design with pin control. The control by the regulating pin is not self-locking.
| Size | Transmission ratio | Regulating screw | Regulating pin | ||
|---|---|---|---|---|---|
| Output speed | Torque | Adjusting Angle | Torque | ||
| 0 | 1:3 | 9 | 0,5 | 41° | 1 |
| 1:4,5 | 10,25 | 51° | |||
| 1:6 | 12 | 60° | |||
| 1 | 1:3 | 8,15 | 0,7 | 48° | 2 |
| 1:4,5 | 9,45 | 57° | |||
| 1:6 | 10,75 | 66° | |||
| 2 | 1:3 | 8,2 | 0,85 | 39° | 4 |
| 1:4,5 | 10 | 47° | |||
| 1:6 | 10,8 | 51° | |||
| 3 | 1:3 | 10,5 | 1 | 45° | 6 |
| 1:4,5 | 12,65 | 52° | |||
| 1:6 | 13,25 | 56° | |||
| 4 | 1:3 | 12,2 | 1,3 | 42° | 10 |
| 1:4,5 | 14,7 | 57° | |||
| 1:6 | 17,4 | 63° | |||
| 5 | 1:3 | 15,3 | 1,5 | 48° | 18 |
| 1:4,5 | 18,3 | 54° | |||
| 1:6 | 19,6 | 58° | |||
| 6 | 1:3 | 15 | 2 | 48° | 30 |
| 1:4,5 | 18,6 | 53° | |||
| 1:6 | 19,6 | 59° | |||
Supplied flange electromotors for sizes 0-6:
| Size | Motor | kW | V | Hz |
|---|---|---|---|---|
| "0" | 4 AP 80-4 | 0,75 | 380/220 | 50 (60) |
| "1" | 4 AP 90 L-4 | 1,5 | 380/220 | 50 (60) |
| "2" | 4 AP 100 L-4 | 3 | 380/220 | 50 (60) |
| "3" | 4 AP 112 M-4 | 5,6 (4) | 380/220 | 50 (60) |
| "4" | 4 AP 132 M-4 | 7,5 | 380/220 | 50 (60) |
| "5" | VC 160 L-4 | 15 | 380/220 | 50 (60) |
| "6" | VC 180 L-4 | 22 | 380/220 | 50 (60) |
