The proper concept of gearboxes adopted by the manufacturer’s designing department has been developed with the help of computer-aided technology and high-quality computing programs. The computer-aided design technology (CAD) has also developed the drawing and accompanying documentation. The result is a product of optimum dimensions and function parameters.

Integrated gearing has made it possible to reduce the gearbox dimensions. Accurate gearing machining reduces vibrations and ensures silent operation.

Large number of combinations of inlet and outlet shafts and flanges make it possible to use the TOS gearboxes for almost all of the required modes of drives.

The gearbox form makes easier the attachments to all types of devices.

Configuration of gears and their fine graduation from i = 5,9 enable the accurate selection of the required outlet revolutions.

Gearboxes are normally provided with motors made by SIEMENS Company.

The gearboxes are provided with priming coat and sprayed polyurethane varnish. In KTM gearboxes the varnish spraying unifies the color of the motor attached.

The gearbox gearings are lubricated with synthetic oil. The standard oil filling has been provided in cooperation with ÖMV.

If smooth change of revolutions, steady speed or steady torque are required, the KTM gearboxes should be fitted with frequency converters.

The gearbox is univocally specified with the type designation. Therefore, the order must include the complete designation with the numerical code as shown in the pattern. When ordering, it is possible to use the order form included in the chapter 12 where even the requirements differing from the standard supplied may be stated. 

KTM is a designation of the spur bevel gearboxes manufactured by TOS ZNOJMO

the gearbox form and style make it possible to use the gearboxes in different operating positions, as shown in Table 2.2. Code numbers 1 to 6 specify the position.

Table 2.2

1. with the pin at the outlet
2. with an electric motor attached.
3. without flanged electric motor IM 3641 FT** (IM B14 FT** ) – smaller flange B14 A
4. without flanged electric motor IM 3641 FT** attached ( IM B14 FT** ) – bigger flange B14 B
5. without flanged electric motor IM 3041 ( IM B5 )attached
6. Flange dimensions and their combinations with gearboxes are included in Tables 8.2 and 8.3.

1. Massive shaft to the left version, chapter 7.1
2. Massive shaft to the right version, chapter 7.1
3. Hollow shaft basic version, chapter 7.2
4. Massive shaft and outlet flange to the left version, chapter 7.3
5. Massive shaft and outlet flange to the right version, chapter 7.3
6. Hollow shaft and outlet flange to the left version, chapter 7.4
7. Hollow shaft and outlet flange to the right version, chapter 7.4

in conformity with the individual types specified in the output table

conforming with Table 8.1. or the electric motor output P₁ conforming with Table 6.1. (see Output parameters)

Spur bevel gearboxes KTM are supplied with the electric motor required by the customer or as
a free shaft-end version or inlet hollow-shaft version, in dimensions meeting the IEC stipulations. 
In case a KTM version without motor attached is required, the electric motor shaft diameter shall be specified in the buying order together with the flange dimension (pitch circle of attaching holes). For selecting the motor, the user should consult the chapter „Electric motors“ where combinations of output, speed, axis height conforming with IEC and other dimensions of electric motors. For detailed information on electric motors see the self-standing catalogue provided by the of electric motor manufacturer.

For the correct selection of the gearbox and driving electric motor the following data must be known: Required total torque M ₂, gearbox output speed n₂, loading mode and corresponding operational coefficient S_m. On the basis of these values, it is then possible to fix the corresponding gearbox size, power and gear ratio „i“.

Torque M₂depends on the required gearbox load and it may be expressed as the force F ₂, which actuates at certain distance on the arm r₂.

M₂ [Nm] = F₂ [N] x r₂ [m]

In order to ensure the gearbox optimum service life at different operating load modes, when selecting the gearbox size, we use so called operating coefficient S _m, which is the product of partial factors, reflecting the individual conditions.

S_m = S₁ x S₂ x S₃ x S₄

When selecting propre gearbox, it is cecessary to see that the operation factor S_m be smaller than service factor of gearbox S_f.

Gearbox service factor S_f determines the approximate ratio of the maximum torque at the gearbox output, which can permanently burden the gearbox, to the actual total torque, which the selected electric motor is able to provide.

M_2max
S_f = ——————— [-]
M₂

Maximum torque M_2maxis fixed for the operating coefficient S_m = 1, as specified in Table 5.1. Values of service factors for the various variants of sizes, gears, and assignment of electric motors are specified in Table 6.1.

For fixing the necessary output of the electric motor P₁the following relation shall be used:

M₂[Nm] x N₂[min^-1] x 100 
P₁= ————————————————- [kW]
9550 x [%]

A portion of the output is consumed for overcoming the gearbox mechanical resistance. This ratio expresses the efficiency  , which is the ratio of the power at the output P₂ to the power at the input P₁.

P₂   
= ————– x 100 [%] 
P₁   

The gear ratio is the gearbox inlet-to-outlet speed ratio

n₁
i = ———– [-]
n₂

n₁[min^-1] – electric motor nominal speed
n₂[min^-1] – gearbox outlet speed

The spur bevel gearboxes KTM are furnished with output shaft with cylindrical pin fitted with a keyway. The values of admissible radial load values are specified in Table 6.1. The admissible shaft load is rated for inlet speed n ₁= 1400 [min^-1], for the given gear and motor output.

For determining this values, as the point of application of the radial force F_radthe shaft half-free end has been taken (see the following figure).

Calculated F_rad may not exceed the maximum admissible radial load of the shaft specified in Table 6.1. 
In case a pulley, chain wheel, toothed wheel and the like are put on the outlet shaft, the actual radial load can be calculated with the help of the following formula:

M₂x k x 2000
F_r= ————————— [N]
D

The admissible axial load of a hollow shaft is determined with the relation

F_r
F_{a max} = —————- [N]
3

When actuating simultaneously, the axial and radial forces may not exceed the load of the shaft

F_ra= F _r– 3 x F_a [N]

The table includes gearboxes ordered conforming the gear ratio for the given output of the driving electric motor. For nominal power and electric motor speed n₁=1400 r.p.m. the torque M₂ and output speed n₂, service factor S_f and admissible output hollow shaft load F_r.

Motor mounting position – terminal board standard location in position 1. Another position of the terminal board shall be indicated in the order, specified as a special requirement.
The chapter of electric motors involves basic technical and dimensional data of the motors of 56 to 160 axis height supplied by Siemens Mohelnice electric motor manufacturer. For additional or more detailed technical information ask for a self-contained motor manufacturer’s catalogue.

Table 8.1 Electric motors

Shape– flange type IM 3041 (IM B5), IM 3641 FT^**, IM 3641 FT^**)- foot-flange type IM 2081 (IM B35)- all assembly shapes according too IEC 34-7 code I/II 

Mounting dimensions– in compliance with IEC 72 / DIN 42673 

Protection– IP 55

Lubrication of gear sets and bearings is indispensable for ensuring reliable gearbox operation along its whole service life. Suitable lubrication provides for high efficiency, essential wear restriction, and silent operation. The KTM gearboxes are normally filled with high-quality synthetic oil as a service-life filling. Therefore, the gearbox housings must not be fitted with filling, checking, and drain holes. Informative quantity of lubricating fillings for the various sizes are specified in Table 10.1.

Use of synthetic lubricants we normally supply, is recommended, nevertheless the use of mineral oils is also possible. Suitable lubricating fillings (equivalents from different manufacturers) are specified in Tab. 10.2.

For medium and light operation and lower surrounding temperature, the mineral oils specified are included in ISO-VG 220 viscosity class; for heavy duty and higher surrounding temperatures, they are included in ISO-VG 320 viscosity class.

Lubricating fillings should be exchanged, in the case of mineral oils, after the first 400 operating hours and then after every 4000 hours of operation.

Synthetic and mineral lubricants may not be mixed. Even mixing synthetic products of different manufacturers may be problematic. In case of passing to another type or mark of lubricant, the gearbox must be cleaned unconditionally.

Single or double sided output shaft may be inserted into the hollow shaft.

The KTM gearboxes may be provided – on special customer’s request – with a suitable type of shaft slip coupling at the output (or the input) for compensating the radial, axial, and angular misalignment of the shaft for limiting the transmission torque, or with an overrunning clutch, or with combination of elastic coupling with slid coupling and of elastic coupling with the overrun clutch.

When dispatched from the manufacturer’s, the external functional surfaces are protected against atmospheric corrosion with a short-term preserving spray coating. Should the gearbox be stored for a longer period of time remaining out of operation, it is indispensable – depending on the environmental conditions – to reapply the preservation. In the case of a long-term storage, the gearbox must be filled with oil in the amount stated in chapter “ lubrication„.

The storage compartment has to be dust-free as far as possible and dry. The storage compartment should not exceed the limits of 0 to 40 ^°C. It is recommended to rotate the outlet shaft through at least one turn every 3 to 4 months. 
The gearboxes have to be transported and stored in the mounting position.