New Products Introduction Development of "SANMOTION F" Stepping Motor 2-phase 42mm-sq. 0.9 Masaaki Oohashi Shigenori Miyairi 1. Introduction The stepping motor has features that are not found in other motors such as open loop control and high hit rate, and as a result, it is widely used as a control motor in OA equipment, medical instruments, and semiconductor manufacturing equipment. Each year, this type of equipment faces growing demands for higher precision, more compact sizes, and lower costs, and so stepping motors are also being called on to provide higher accuracy, lower vibrations, compact size with Fig. 1 ''SANMOTION F'' high torque, and lower costs. Previously, applications that required high precision used complexity of the drive circuits in the 5-phase stepping motor This report presents a product overview and features of the 2-phase 42mm sq. 0.9 stepping motor ''SANMOTION F'', means that the system cost was high. Therefore, higher which was newly developed to respond to these needs. the 5-phase stepping motor with its small step angle, but the accuracy has been called for in 2-phase stepping motors which have simple drive circuits and low system cost. 420.25 Lead wire UL3385 AWG24 1.50.76 4-310.25 4-M3x0.5 240.5 +1 15 0 (Effective length) 0 S 22 0.05 0 5 0.013 0 300 MIN. 330.5 5 0.013 151 S R3 MIN. 4.50.15 Cross section S-S 4.50.15 Fig. 2 External dimensions of the 2-phase 42mm Sq. 0.9 stepping motor ''SANMOTION F'' SANYO DENKI Technical Report No.20 Nov. 2005 34 Table 1 Specifications of 2-phase 42mm Square 0.9 Stepping Motor SANMOTION F Holding torque Model Winding Single-ended Dual-ended system spindle spindle Unipolar Bipolar Unipolar Bipolar Unipolar Bipolar Rated current Winding resistance Rotor inductance Rotor inertia Mass Nm MIN. A/phase /phase mH/phase x10-4 kgm2 kg 3.2 0.044 0.24 0.066 0.29 0.089 0.38 At 2-phase excitation SH1421-0441 -0411 0.20 1.2 2.7 SH1421-5041 -5011 0.23 1 3.3 8 SH1421-5241 -5211 0.23 2 0.85 2.1 5.3 SH1422-0441 -0411 0.29 1.2 3.1 SH1422-5041 -5011 0.34 1 4 14 SH1422-5241 -5211 0.34 2 1.05 3.6 5.3 SH1424-0441 -0411 0.39 1.2 3.5 SH1424-5041 -5011 0.48 1 4.7 15 SH1424-5241 -5211 0.48 2 1.25 3.75 2. Product overview Nameplate Lead wire Stator Lead wire outlet 2.1 Motor Dimensions The external view of the motor is shown in Fig. 1, and the external dimensions of the product are shown in Fig. 2. Lead wire holder Inner-diameter spigot joint Resin cover Bearing Bearing Shaft 2.2 Specifications Table 1 shows the product specifications. The typical winding systems are the unipolar type (6 lead wires), which is commonly used in Japan, and the bipolar type (4 lead wires), which is commonly used in Europe and the United States. End bracket Front bracket Rotor In the unipolar type, the drive circuits can be made with a simple design for a low system cost. The bipolar type features a high usage ratio of motor winding for providing a large torque. Fig. 3 Motor Structure 3. Features of the product 3.1 High Resolution More teeth for the rotor and stator were used to enable a high resolution. In this product, the die precision of the rotor Fig. 4 shows a vibration comparison of the basic step angle 1.8 stepping motor and the newly-developed basic step angle 0.9 stepping motor. The superiority of the 0.9 stepping motor is evident in nearly all speed ranges. and stator were improved, and the number of teeth was doubled from before. This enabled the obtaining of a high resolution at a basic step angle of 0.9 compared to the regular basic step angle of 1.8 . 3.3 High Torque A high torque design in the stepping motor enables it to move large loads. Also, if the loads are identical, the smaller motor can be selected. The more compact design takes up less space, 3.2 Low vibration and low noise Fig. 3 shows the motor structure. The brackets used an conservation. The primary factor that contributes to the torque ''inner diameter spigot system'' where they were assembled characteristics of the stepping motor is the magnetic circuit based on the stator inner diameter. In this system, the rotor design of the stator and rotor. This development used new, and stator centers have high-level concentricity that enables innovative methods and various types of simulations to develop better rotational balance for lower vibrations and lower noise. the optimum magnetic circuit design. As a result, the torque The inner diameter spigot system also enabled higher rigidity was improved by 1.5 times from the conventional product. for the stators for lower vibrations and lower noise. 35 has lower cost, and also contributes significantly to resource SANYO DENKI Technical Report No.20 Nov. 2005 Fig. 5 shows a comparison of the torque characteristics of Development of "SANMOTION F" Stepping Motor 2-phase 42mm-sq. 0.9 3 Driver: Sanyo constant current circuit Supply voltage: 24 V DC Excitation current: 1.2 A/phase (Ave.) Excitation system: 2-phase excitation system Tachogenerator: 11TG (7V/1000 min-1) 2.5 2 output (Vrms) Conventional motor: 103H5208-0410 (1.8 step) 1.5 TG Developed motor: SH1422-0411 (0.9 step) 1 0.5 0 0 20 40 60 80 100 120 140 160 180 Number of rotations -1 Fig. 4 Comparison of Speed Fluctuations in Basic Step Angle 0.9 and 1.8 0.5 5 Driver: Sanyo constant current circuit Supply voltage: 24 V DC Excitation current: 1.2 A/phase (Ave.) Excitation system: 2-phase excitation system 0.4 3 2 Torque Torque 4 Load inertia: JL=0.94x10-4kgxm2 (including rubber coupling) 0.3 Developed motor: SH1422-0411 (motor length: 39mm) 0.2 Conventional motor: 103-594-0240 (motor length: 40.2mm) 1 0.1 0 0.0 0.1 1 10 100 Pulse rate 50 100 500 1000 Number of rotations -1 2000 Fig. 5 Comparison of Torque Characteristics this new 0.9 stepping motor and a conventional 0.9 stepping contained within this protrusion because it is difficult to motor. provide space for the connection between the lead wire and motor coil wire inside the motor. However, a smaller device 3.4 Compact Size for Less Space size enables a motor design that takes up less space, and this Many stepping motors have protrusions where the lead wire protrusion of the lead wire outlet can be a hindrance to outlets extend from the motor square body. The connection is developing a compact size. This is why a stepping motor SANYO DENKI Technical Report No.20 Nov. 2005 36 Development of "SANMOTION F" Stepping Motor 2-phase 42mm-sq. 0.9 without any protrusion for the lead wire outlet is desirable. Most conventional stepping motors without protrusions for the lead wire outlet make the connection between the lead wire Masaaki Oohashi Joined Sanyo Denki in 1982. Servo System Division, 3rd Design Dept. Worked on stepping motor development and design and motor coil wire inside the stator slot. However, because the stator slot is a space for storing the motor coil, the connecting of the lead wire and motor coil wire in this space naturally limits the length of the motor coil and reduces the motor characteristics (torque and temperature rise). To resolve this problem, the new ''lead wire holder system'' was devised and implemented. In the lead wire holder system, the resin-made lead wire holder and end bracket structure are designed so that the connection between the lead wire and motor coil wire can be made in less space. Also, because this system does not use a stator slot, the protrusion of the lead wire outlet can be eliminated without sacrificing motor characteristics for enabling a more compact size that takes up less space. 4. Conclusion The 2-phase 42mm square 0.9 stepping motor SANMOTION F has a high resolution, compact size, and high torque and can contribute to higher precision, lower costs, and more compact sizes for OA equipment, medical instruments, and semiconductor manufacturing equipment. We will continue to work to develop motors using other technology for providing even more improved performance in the future. 37 SANYO DENKI Technical Report No.20 Nov. 2005 Shigenori Miyairi Joined Sanyo Denki in 1990. Servo System Division, 3rd Design Dept. Worked on stepping motor development and design