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Contribution to Innovative Manufacturing


Miki Pulley was established in 1939 by Yoshiharu Miki as a comprehensive manufacturer of power transmission and control equipment. At the time of its founding, MIKI invented the belt-type continuously variable speed PULLEY and played a major role in technological innovation in Japan. Since then, we have continued to develop, manufacture, and sell speed control, position control, and

rotation transmission devices.

Our products, represented by couplings, clutches, and brakes, are used in all kinds of industrial equipment, including machine tools, semiconductor manufacturing equipment, industrial robots, AGVs, medical equipment, and packaging machines. In addition, we have been actively expanding overseas business from early stage, promoting technical partnerships with top manufacturers in the United States, Germany, Italy, Switzerland, Sweden, etc., and continuing to expand our business domain.

Various product lineup

Miki Pulley handles the following products.

Speed control: belt type continuously variable speed PULLEY, inverter, geared motor

Position control: electromagnetic clutch/brake, brake motor

Rotation transmission equipment: couplings, shaft-hub friction fasteners, torque limiters


Industrial machinery generally adopts many shaft-to-shaft connection structure, and our couplings play an important role there. Completely centering two different axes is a very difficult task. Maintaining centering becomes even more difficult due to deflection of the shaft by operation of the machine, thermal expansion of the shaft, distortion of the support base and bearing wear out after long-term use. Those problems can be solved by selecting the suitable coupling for the application.

There are many different types of couplings, Miki Pulley was one of the first to adopt a leaf spring type, and developed the SF (Servoflex Series) couplings that are ideal for high-precision control of servo & stepper motors. High-rigidity coupling SFC/SFS/SFF models ideal for NC lathes/ machining centers/ chip mounters/linear actuators/scalar robots/electric discharge machines/semiconductor manufacturing equipment. SFM model for CNC machine main spindles that can handle a maximum speed of 24,000 rpm. We have a lineup of SFH models that are ideal for equipment that requires large torque, such as gantry machining centers, printing machines, testing machines, and wind power generators, and we boast the top share of adoption by machine tool manufacturers in Japan.

In addition, we have another choice for servo & stepper motor, STF model with high damping performance rubber coupling. The newly developed laminated rubber element (HNBR) achieves high damping and low reaction force. Absorbs vibrations more quickly than the SF series, which uses metal for its elastic parts. Servo & stepper motors are capable of highprecision position and rotation control, but resonance may occur depending on the operating conditions. Resonance can be avoided in a wide range of operating speeds by electrical control, as well as by installing an STF coupling to realize stable high-speed control.

Even in the same drive system, the coupling selection depends on the required control method and application. Miki Pulley can offer more than 33 models that can be selected according to the type of motor and the mechanism of the driven side. You can select suitable one for your application. The torque range can be covered from 0.25 to 18,000Nm.


Electromagnetic clutch/brake

In addition to couplings, clutches and brakes also play an important role in industrial machinery. Electromagnetic clutches and brakes control power and rotational motion using electromagnetic force generated by energizing coils. Clutches connect and disconnect power, and brakes control and hold rotational motion. Electromagnetically actuated type clutch/brake operates by energizing the coil, and non-excitingly actuated type brake operates with the force of a spring when the coil is de-energized, such as during a power outage. Moreover, we have an extensive lineup of products, including electromagnetic tooth clutches, brake motors, and unit products that combine those items. Particularly, nonexcitation actuated brakes represented by the BX series is ideal product for various industrial robots and AGVs. Demand for those items is expected to increase further more in booming robot market.


BXR-LE series (ultra-compact)

There are two types of robot stop control: servo motor control and physical control using electromagnetic brakes. Servo motor control can be divided into dynamic braking and regenerative braking, but both are intended for braking to stop the motion, and must be powered. Electrical control alone cannot keep the device in a stopped condition when there is no power. Therefore, a non-excitation type brake is required when the power shut down.

For example, when a collaborative robot detects an abnormal approach by a human worker, it is stopped by servo motor control and the servo lock is activated. If the abnormality continues and the power of the robot is turned off, the non-excitation brake will be activated. In addition, in an emergency when the power supply is shut down for some reason, the non-excited brake also works to stop the motion and keep same position of the equipment. In this way, the combination of servo motor control and BXR-LE can ensure safety and security.

Non-excitation brakes are necessary for the safety of robots, but they also need to be “downsized” and “energy-saving.” Collaborative robots are moving closer to human workers, downsized is essential in order to secure a working environment. Furthermore, the demand for energy saving is increasing due to the social background of realizing a de-carbonized society.

The BXR-LE series achieves long-time operation of battery-powered equipment through its energy- saving design. Normally, an applied voltage of 24V is required to operate a non-excitation brake, but the BXR-LE lowers the voltage to 7V after 0.2s of 24V application, making it possible to greatly reduce power consumption during operation. In addition, the minimum thickness of the brake body is 14 mm, BXR-LE model is widely used in various type of robot system.

New Thai office established

In July 2022, Miki Pulley (Thailand) was newly established. Furthermore, we have opened a representative office in Malaysia from January 2023. Southeast Asian countries are positioned as important production bases for electronics-related products and auto parts. With the establishment of an office in Thailand, which is the geographical center, it is now possible to cover the entire Southeast Asian country. In addition, Malaysia and Singapore where the development of robots and cutting-edge technology focused on semiconductor manufacturing equipment, is also active. Miki Pulley’s products and services will continue to evolve along with the growth of these markets.

Mr. Kenji Hayasaka

Mr. Calvin Lok

For more detailed information, please refer to the QR code below


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