K-Series Helical Gear Reducer

┃ Advantage

● High power density

● Wear-free design

● Long service life

● Multi-stage gear reducers meet low-speed requirements.

● The entire series can deliver low backlash.

┃ K Series (Level 3)

Helical–bevel gear reduction motors are high-efficiency, right-angle shaft reduction motors, ideal for applications requiring high torque and excellent wear resistance. Low-backlash helical–bevel gear reducers can be used for precise positioning control.

┃ We can supply gear reducers in the following specifications:

● Base mounting or flange mounting

● B5 or B14 flange mounting

● Solid shaft or hollow shaft

● Hollow shaft: single key, locking disc, spline, TorqLOC® hollow shaft

┃ SEW K-Series Bevel Gear Reducers

Three-stage helical–bevel gear units deliver high output torque, with options for hollow or solid shafts and mounting configurations including flange, base‑mounted, or torque arm.

Transmission efficiency as high as 98%, compact size, lightweight, low vibration, and low noise.

Output speed: 0.1 rpm – 522 rpm

Output torque/power: 200 Nm – 50,000 Nm / 0.12 kW – 200 kW

Frame size: K37, K47, K57, K67, K77, K87, K97, K107, K127, K157, K167, K187

KS37,KS47,KS57,KS67,KS77,KS87,KS97,KS107,KS127,KS157,KS167,KS187

KA37, KA47, KA57, KA67, KA77, KA87, KA97, KA107, KA127, KA157, KA167, KA187

KF37,KF47,KF57,KF67,KF77,KF87,KF97,KF107,KF127,KF157,KF167,KF187

KAF37,KAF47,KAF57,KAF67,KAF77,KAF87,KAF97,KAF107,KAF127,KAF157,KAF167,KAF187

KAT37,KAT47,KAT57,KAT67,KAT77KAT87,KAT97,KAT107,KAT127,KAT157,KAT167,KAT187,KAZ37,KAZ47

KAZ57,KAZ67,KAZ77,KAZ87,KAZ97,KAZ107,KAZ127,KAZ157,KAZ167,KAZ187

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　　 Types and Mechanisms of Gear Reducers

　　Gear reducers are representative of transmission systems. Based on gear type, shaft arrangement, and gear configuration, currently used reducers can be classified as follows: (1) parallel-axis gear reducers, (2) orthogonal-axis gear reducers, (3) vertical non-intersecting-axis gear reducers, and (4) coaxial gear reducers.

　　 Types and Mechanisms of Parallel-Axis Gear Reducers

　　Parallel-shaft gear reducers employ spur gears, helical gears, or herringbone gears, with the input and output shafts aligned parallel to each other.   The typical reduction ratios are as follows: for single-stage shafts, 1:1 to 1:7; for two-stage shafts, 1:10 to 1:30; and for three or more stages, 1:5 to 1:200. The general characteristics of parallel‑shaft gear reducers are as follows:

　　For high-precision gears, the transmission efficiency is very high (98% to 95% for a single-stage gear reducer).

　　With proper lubrication, it can operate for a long time. Thanks to the use of standardized gears, it can be manufactured relatively inexpensively. A gear reducer with spur gears is used to increase speed.

　　Spur gear reducers are typically larger in size. Compared with worm gear reducers of the same ratio, they have a bulkier external profile, more components, and a less favorable structural design. Consequently, they are employed in machinery where the load-side rotational speed is relatively high, or where the output speed needs to exceed that of the prime mover (for speed increase).

　　Parallel-shaft gear reducers typically use helical gears and are employed in steel‑making equipment, marine vessels, cranes, elevators, conveyors, and more. In automated machinery, they are also referred to as gear motors—reducers that are directly coupled to an electric motor.

　　 Characteristics of Parallel-Axis Gear Reducers

　　Spur gear:

　　The tooth profile is straight, with the teeth parallel to the shaft. It is simple to manufacture and the most widely used; it is often employed to increase speed.

　　Spur gear

　　Helical gear:

　　The tooth profile of a spur gear is helical. It offers higher strength, a higher contact ratio, and lower noise compared to spur gears, but it generates axial thrust. It is primarily used for power transmission.

　　Helical gear

　　Herringbone gear:

　　A type of helical gear consisting of a pair of helical gears arranged symmetrically in opposite directions. Similar to helical gears, it does not generate axial thrust. It is primarily used for high‑load power transmission.

　　Double helical gear

　　 Types and Mechanisms of Orthogonal-Axis Gear Reducers

　　Orthogonal-axis gear reducers, also known as bevel gear reducers, feature input and output shafts that are perpendicular to each other. The gears used include straight bevel gears, helical bevel gears, spiral bevel gears, Zerol bevel gears, face gears, and crown gears. Orthogonal-axis gear reducers are commonly employed in field applications as power‑distribution devices.

　　The accuracy of right-angle gear reducers is lower than that of parallel-axis gear reducers; in particular, the pinion supported on a single side is prone to misalignment, resulting in poor tooth surface contact and slightly reduced transmission efficiency (98%). Right-angle bevel gear reducers are suitable for low-speed operation below 1,000 rpm, with standard reduction ratios of 1:1 and 1:2.

　　In addition, compared with straight‑bevel gear reducers, spiral bevel gear reducers feature a higher contact ratio and are well suited for heavy loads and high rotational speeds. Typically, the reduction ratio for a single stage is limited to 1:6 or less. Table 2.2 lists the gears used in bevel gear reducers.

　　 Types and Mechanisms of Helical Gear Reducers

　　Gear reducers in which the input and output shafts are offset and intersect at right angles typically employ hypoid gears or worm gears. In particular, worm gears have long been used for speed reduction and remain widely employed today. The characteristics of the gears used are shown in Table 2.3. The salient features of these reducers are as follows:

　　High single-stage reduction ratio

　　The reduction range is 1:5 to 1:100. Two worm gear reducers combined can achieve a reduction ratio of 1:10,000.

　　Low noise and vibration

　　Worm gears primarily rely on sliding contact, resulting in low noise and vibration. Leveraging this characteristic, worm gear reducers were once used as drive sources. However, due to their low transmission efficiency, they have now been replaced by reducers employing hypoid gears or other types of orthogonal or parallel-axis gears, as described below.

　　The input shaft and the output shaft are at a right angle,

　　Even when integrated into the gearbox, it features a reduced number of parts and a compact footprint, thereby saving installation space.