Power spring
A spring motor (clock spring) is a component made by winding a strip of spring material into a spiral; it extracts the elastic energy stored by winding as rotational torque. The main types are the spiral springs and clock springs that are assembled onto a shaft or case to obtain rotational force, and the spring motor units that are housed in a case and pull out and rewind a take-up cord or string. Materials include hard steel wire, carbon tool steel, and stainless steel. Applications include automotive parts, motor start assistance, lift mechanisms for furniture, and automatic take-up of cords and strings, in situations where a return force or rotational force is needed without using a power supply.
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Power spring
Spiral Spring
Hard-drawn steel wire spiral springs for automotive and motor applications. Maximum torque 1.09 to 12.0 N・m.
Spring net
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Power spring
Clock Spring (Free Size)
Carbon tool steel and stainless steel clock springs available with outer diameters of 50 to 112 mm. Strip thickness 0.2 to 0.8 mm.
Spring net
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Power spring
Spring Return Cord Reel Unit
A case-type spring return unit that pulls out a cord and retracts it. Output force 2.45 to 9.8 N.
Spring net
How to choose Power spring
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1. Check the required maximum torque
For spiral springs and clock springs alone, check whether the rotational force needed to operate the mechanism is satisfied using the maximum torque. Listed products range from 1.09 to 12 N·m. Since torque varies with the amount of winding, check that the required torque is not below the listed value across the range of rotation angles used.
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2. Select an outer diameter that fits the storage space
Outer diameter D is the outer diameter of the spring in its wound state, and determines whether it fits within the inner diameter of the case or housing it is installed in. Listed products range from 42 to 100 mm, and some free-size products can be manufactured to a specified outer diameter. Also allow for the extra space the spring occupies when unwound.
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3. Adjust torque and dimensions with thickness and width
Even with the same outer diameter, the generated torque increases as the strip thickness t gets thicker and the strip width b gets wider. As thickness increases, the number of turns tends to decrease, reducing the rotation angle. Listed products have a strip thickness of 0.2 to 0.8 mm and a strip width of 5 to 16 mm, so also confirm that the strip width fits within the axial mounting width.
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4. Select units by cord output and stroke
For spring motor units, the selection criteria are the cord output, which is the force pulling the cord, and the stroke, which is the length over which the cord can be pulled out. Listed products have a cord output of 2.45 to 9.8 N and a stroke of 1500 mm. Check that the output is sufficient to reliably return the object during rewinding and that the stroke is long enough for the required pull-out length.
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5. Review service life against cycle count
Spring motors suffer breakage and loss of force from fatigue when repeatedly wound and unwound. For listed products, the guideline service life is 200,000 cycles. Estimate the required number of cycles from the expected usage frequency and service life of the equipment, and if this exceeds the guideline, determine a replacement interval.
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6. Choose a material suited to the operating environment
Hard steel wire (such as SWRH 62A) and carbon tool steel are for general applications, and rust must be watched for in humid or wet environments. Where corrosion is a concern, consider stainless steel. Surface treatment and the presence or absence of grease also affect friction and corrosion resistance.
This guide was written by AI based on the listed products' documents and specification items. Check each manufacturer's documents before adopting.