Constant Torque Springs

Constant torque springs are normally used as the constant torque spring motor, which is consisted of two drums and a prestressed winding flat strip.

Yongsheng produces various constant torque springs and supplies full customization services including design, manufacturing, mounting & assembly.

YongSheng constant torque springs are made of high yield 301 stainless steel, which features anti-rust, high resistance, high hardness. when it be coiled through the springs forming machine, it will generate resistance for uncoiling.

  • Higher output force in limited space.

  • Unlimited useful turns, which is high efficiency.

  • Easy to deploy multiply load, and get the bigger rotational force.

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constant torque spring
constant torque spring motor

YongSheng constant torque springs

  • High life circle, from 5000-25000 times depend on the different environment and product specifications, with special technology, our constant torque springs have a longer life than competitive.
  • Favorable price, based on numerous standard tools, you can get a favorable price, even for the customized products, you will benefit from our rich experience and high efficiency.
  • High quality with strong performance, YongSheng performs stringent quality control criteria throughout the entire production process, just for almost zero defective rates.
  • One-stop service, pre-sales, and after-sales expertise guidance, as well as assembling and adjusting additional service.

Constant Torque Spring design Mechanism

Constant torque spring seems like the constant force spring in appearance, we need to fix it to a shaft as the storage drum when using it, and the spring’s end is connected to another shaft that adheres to a spool as the output drum.

when the force exerted on the spool, which will lead the spring to unwind around the shaft and the storage drum will generate counterpart force, we often use this retractable feature in many applications like cordless window blinds/window shades, automatic retractable devices, and so on.


Standard Constant Torque Springs
Product No.T(mm)W(mm)L(mm)Min.Torque(

T: Thickness W: Width L: Length (Choose a product in the table, you’ll get a favorable price)

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Select one type from the above table, and you will get a favorable price!

Inquiry our expert with your ideas, we will bring it to reality.
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The Constant Torque Spring: The Ultimate Guide

Constant torque springs are a popular choice of spring.

Their small and compact nature makes them mission-critical.

If you are looking up for information about constant torque springs, in this article you will get answered questions to help you make an informed decision.

What are constant torque springs?

Constant torque springs are similar to the constant force springs, they are made of steel stripe, and will generate counterpart force when coiled through the spring forming equipment.

When we use the constant torque springs, we need to fix it to a shaft as the storage drum, and the spring’s end is connected to another shaft that adheres to a spool as the output drum.

when the force exerts to the spool, which will lead the spring to unwind around the shaft and the storage drum will generate counterpart force, we often use this torque force in the applications.


Applications and Functionality of constant torque springs 

You can use constant torque springs across various applications. These include conveyors, medical, imaging devices, retracting cables, wind-up motors, feeders, etc.

Features of Constant torque springs

Constant torque springs the following characteristics.

  1. Smooth operation. Due to minimal inter coil friction.
  2. Efficient output. Due to high torque.
  3. A high number of output cycles with over 50 possible turns
  4. The most life cycles you can get are 35,000 times.

These characteristics ensure that you get substantial advantages.

Some advantages include:

  1. They deliver greater torque in a small package.
  2. The springs have high efficiency, and every turn is useful.
  3. They exert an almost constant torque when entirely turned.

Keypoints in Constant torque springs

When you decide to customize your constant torque springs, there are several key points that should be considered.  They are material, thickness, length, width, natural diameters, and spool diameter.

  1. Material – We make the springs from Type 301 stainless steel or high carbon steel.  Contact us to help you choose the standard size and material.
  2. Lifecycle – Estimating the life of your spring is crucial, cause it’s various from requirement and environment. We provide you with springs with a higher lifecycle ranging ranges from 5000-25000.
  3. End detail – The end detail is what connects your spring to the output drum. End detail designs may vary. In case your application requires a unique end detail, please contact us.
  4. Spring’s environment – Where you place your spring is quite essential. Corrosive environments affect performance negatively. Extreme temperature spaces also adversely affect performance.
  5. Finalizing your spring design – Once we have reviewed your design parameters, we check our standard chart for the best fit.
  6. Load – The load decides your springs most factors like thickness, width, material, etc.
  7. Shaft dimension – The shaft dimension will decide the size of your springs.

We have a professionals R &D team with rich experience who will provide you feasible solutions.   Please consult with us early enough to ensure you get springs optimized for your needs.

Assembly of Constant torque springs

Assembly of the springs requires the use of two drums. A storage drum and an output drum. You can use a shaft and a spool, respectively. First, you need to attach your spring to the storage drum.

The opposite end of the spring is connected to a shaft.  The shaft is then attached to a spool, which now forms the output drum. When a load force is exerted on the spool, the spring is unwound on the storage drum. The action causes the storage drum to produce a corresponding force. YongSheng not just manufacture constant torque springs, but also have the services to assemble the constant torque spring motors


How To Attach a Constant Torque Spring


You open up your constant torque spring, attach the outer end to your storage drum,

Then spread it around on the storage drum until the end of the spring.

Two Types of Constant Torque Springs Assembly

There are two types of constant torque springs assembly, also two types of constant torque spring motors, like the illustration below:


With type A, the spring comes with constant torque (zero gradients), low output torque, and misses the intercoil friction, limited life.

Type B comes with an inner and outer diameter, straight head torque with an extra 10% of operating strength, and a recommended working spring length.