Shindengen Rotary DC Solenoids Technical Guide
Visit our webpage for Shindengen Rotary DC Solenoids to view all available models and for access to datasheets.
Rotary Solenoid Design
The rotary solenoid’s design starts from a standard flat face push-pull solenoid. The rotary solenoid then incorporates the mechanical design principle of an inclined plane to convert linear motion to rotary motion. There are three uniform inclined planes (spiral grooves) that are stamped into both the case and the armature, called “ball races”. These provide both a means of converting linear motion to rotary motion and a secondary bearing system to support this rotary motion. (See Fig.1)
- Ball races are specially designed to provide a constant torque output over the complete angle of rotation at 25% duty cycle.
- The rotary solenoid uses an enclosed coil and therefore provides maximum magnetic efficiency.
- The magnetic circuit is very short so high efficiencies in terms of torque output can be obtained, and energization / response times are very quick.
The starting torque shown in our product catalog pages is the gross value output at 20°C. With the addition of the return spring, the solenoid’s net output is the gross starting torque minus the return spring torque.
Rotation Angle Direction of Rotation
A. Use of an External Stopper (see Fig 2).
The angle and direction of rotation are predetermined (and fixed) by the manufacturing process of the three ball races that are in the case and armature.
The degree of rotation can be reduced (example: a 35° right-hand (RH) rotation solenoid reduced to 30° RH rotation), by the use of an external stopper. However, to assure that the solenoid operates properly it is imperative that the solenoid armature always be allowed to return to 0° or unenergized position.
B. Direction of Rotation (see Fig. 3)
The normally accepted convention to describe the rotation of the rotary solenoid is that the direction of rotation is viewed from the armature plate (top) of the solenoid. Clockwise rotation is right-hand (RH) rotation, and counter clockwise rotation is left-hand (LH) rotation.
C. Rotation Angle Available
The rotation angles are available as follows:
|Size301||25°, 35°, 45°||RH & LH|
|Size341||25°, 35°, 45°, 67.5°||RH & LH|
|25°, 35°, 45°, 67.5°, 95°||RH & LH|
In Shindengen’s design for rotary solenoids linear motion is converted into rotary motion. The use of the inclined plane (ball races) also generate a small axial stroke; about 0.7 to 2.6 mm depending upon the amount of rotation and the size of the solenoid.
|SIZE||301||341||401||490, 491||590, 591||700||870,874|
|Axial travel (mm), approx.||0.7||0.9||1.2||1.5||1.6||2.3||2.6|
Standard Available Accessories
The standard rotary solenoid is available with different accessories to meet your application requirements. (See Fig. 5)
A: Shaft extension on the armature plate
B: Shaft extension on the base plate
D: Dust cover over armature plate
R: Return spring provided
T: Tapped holes in armature plate
The coil data of rotary solenoids shows the values at ambient temperature 20°C and with a standard heat sink. When a solenoid is used at the ratings mentioned in the coil data, it is designed so that the coil temperature rises and reaches equilibrium at approximately 85″C. In applications where the ambient temperature is higher than 20°C or the heat sink is smaller than indicated in the catalog, possible thermal damage can occur. Temperature rise tests should be performed by the customer to assure that the coil does not reach 120°C. Custom coils can be constructed to operate at temperatures higher than 120°C without thermal damage. Please consult our sales staff for further details.
B. Shaft Modifications
It is not recommended that the customer modify the shaft, as the shafts are fabricated before assembly. Special configurations can be supplied. Please consult our sales staff for further details.
C. How to Use the “T” Feature (tapped armature plate)
The rotary solenoid does have axial movement in the armature plate position during energization and de-energization. When directly attaching a mechanism to the armature plate, the load must allow for free movement in the axial direction. Also, the attaching screws cannot be longer than the thickness of the armature plate or interference in the rotary motion will occur.
|Insulation class:||Class E (120°C), Lead wire class A (105°C)|
|Dielectric strength:||AC 1000V 50/60 Hz 1 min. (at normal temp. and normal humidity)|
|Insulation resistance:||More than 100 Mohm at DC 500V megger (at normal temp. and normal humidity)|
|Expected life:||Standard life: 2 million cycles Extended life: 10 million cycles Long life: 50 million cycles|
How to Select a Rotary Solenoid
Before selecting a rotary solenoid, the following information must be determined:
The actual torque required in the application should be increased using a safety factor multiplier of 1.5 to arrive at the torque value that should be used in your specification.
B. Duty Cycle
Use the following formula to calculate duty cycle. Also note the maximum on time.
Duty Cycle (%) = On Time + Off Time x 100
C. Rotation Angle
Rotation angle is determined by application requirements.
D. Rotation Direction
Rotation direction is determined by application requirements (note direction of armature plate).
E. Operating Voltage
Operating DC voltage is determined by the application and voltage available.
After determining the specifications listed above the correct solenoid for the application can be selected using the torque characteristics tables. Coil data is also provided in tables that use American Wire Gauge (AWG) for magnet wire. If the exact operating voltage is not in the coil data table use the nearest voltage shown in the table.
Note: When the operating voltage falls between 2 coil sizes, always use the higher AWG numbered coil to prevent potential thermal damage. To determine the torque output of the solenoid after temperature rise, please use the amp-turn gross torque tables located at the end of this technical guide after calculating the amp-turns.
When ordering a rotary solenoid, the correct part number needs to be determined, from the following combination of characteristics (1-5):
- M-Metric Thread
- Solenoid Size (example: 490)
- Coil Wire Size (AWG no.)
- Angle of rotation, direction of rotation and accessories (see Table 3)
- Expected life (determined by selection of bearing type)
R = Standard Life Bearing
RE = Extended Life Bearing
RL = Long Life Bearing
Example of a complete part number:
The part number above distinguishes a rotary solenoid with  SAE threads;  size 490;  26 AWG coil wire;  35°right-hand rotation with accessories of armature side shaft extension and return spring provided;  standard life bearings.
For standard rotary solenoids (no modifications) the solenoid label will include the part number and date code. The date code identifies the year and week of manufacture.
Example part number: F 490 26 141 R 9401
|SAE Thread||Solenoid Size||Coil Wire|
|Rotation & Accessories||Rotary & Bearing Life||Date Code|
(year and week)
Accessories Definition Table
|Accessories||Clockwise Rotation (RH)||Counter Clockwise Rotation (RH)|
Use the links below to access performance charts for Rotary DC Solenoids.
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