What is a direct drive encoder? Direct drive principle and features introduced

In traditional drive technology, the motor drives mechanical equipment through various mechanical devices such as screw, gear box, pulley and coupling to increase the final drive torque.

However, mechanical transmissions often have gaps and inevitably cause misalignment. In addition, mechanical wear and tear can lead to energy loss, and sometimes it can generate huge noise and require regular maintenance.

Direct drive system

In recent years, the trend of direct drive systems can be clearly seen in the field of electric drives. The direct drive system has no mechanical parts such as belts or gear boxes, and it is characterized by high accuracy and high reliability, which greatly improves the performance of the equipment.

On the one hand, this makes it easier to manufacture and integrate the equipment. On the other hand, the cost of maintenance and use is greatly reduced.

With the direct drive system, complex mechanical transmission components are no longer needed, simplifying the overall mechanical design and making the entire system very compact.

Direct drive system

Advantage

1. Longer life without wearing parts such as gears and belts

2. Less maintenance Regular maintenance components such as screwless, gearbox, etc.

3. Higher energy efficiency No wear, reduce energy loss

4. Faster response No coupling required, direct connection

5. More accurate, almost no backlash

6. Compact design No mechanical transmission components

7. Smooth running No wear, no noise

Equipment manufacturers may often think that the cost of direct-drive motors is high, but in the long-term (such as design, use and maintenance, etc.), direct-drive systems have a lower total cost of ownership.

Direct drive motor

Direct-drive torque motors evolved from synchronous servo motors. They usually have more magnetic pole pairs and higher power density, so they have a large output torque at low speeds. It is mainly composed of components such as the motor housing, windings, permanent magnets, bearings and feedback encoders.

The direct drive linear motor is equivalent to a synchronous servo motor cut from the center and tiled. The stator of the motor is composed of permanent magnets, and the rotor is a winding coil and is connected to the driver.

Direct drive encoder

As the core feedback element of a direct drive motor, the choice of encoder plays a crucial role in the performance and structure of the entire direct drive system. As an innovative provider of industrial automation products, SICK recognized early on the trends in the use of direct-drive systems and developed a series of custom servo feedback encoders:

1. Servo feedback encoder for torque motor and turntable applications

SES/SEM70, SES/SEM90 and SEK160

2. Servo feedback encoder for linear motor

TTK50 and TTK70

These servo feedback encoders are equipped with the industry-standard HIPERFACE® interface and are compatible with the world's leading transmission systems.

SES/SEM70

Motor Feedback Solution for Precision Hollow Shaft Motors and Direct Drive Motors.

With the SES/SEM70 rotary motor feedback system using the HIPERFACE® industry-standard interface, SICK offers a new choice for hollow shaft motors and direct drive motors. The motor feedback system works in an integral scanning manner and can be directly mounted on the drive shaft without additional installation tools, eliminating the need for racks or connectors and other transmission components. In addition, a mechanical multi-turn function can be used to record the number of revolutions of the rotation, eliminating the need for additional components such as an external buffer battery. The small size configuration saves space and weight, and is sturdy, reliable and never worn due to the use of bearingless technology.

SES/SEM70

Features

1. Single-turn and multi-turn variants with 25 mm/50 mm hollow shafts

2. 32/64 cycles of pos/cosine per circle and 4,096 cycles per circle

3. HIPERFACE® Interface and Expansion Tags

4. Maximum speed: 8,500 rpm/3,000 rpm

5. Easy to install without special installation tools

6. High shock and vibration resistance

TTK70

High-accuracy position and velocity measurement scheme for linear motors.

Accuracy, speed, and dynamic performance play a particularly important role in linear motion measurement. The TTK70 compact linear measuring system with HIPERFACE® or SSI interface meets all these characteristics. Magnetic working principle, long measuring length and very high resolution provide a variety of application options for absolute position and speed detection. The non-contact measuring system consists of a compact read head and a magnetic stripe. The read head is responsible for detecting the position value. The magnetic strip is an inductive scale with magnetic graduations using incremental orbits and absolute orbits.

TTK70

Features

1. Non-contact absolute position and speed detection without reference operation

2. Use HIPERFACE® or SSI interface

3. Measurement length up to 4 m

4. Suitable for high moving speeds up to 10 m/s

5. Reliable measurement even when the magnetic stripe is contaminated or condensed

6. Reliable measurement even when the magnetic stripe is contaminated or condensed

Speaking of so many principles and features of direct drive, what are the applications of direct drive?