Why Does The Planetary Roller Screw Have Greater Thrust?

The reasons why the planetary roller screw has greater thrust are as follows:

1. Linear contact design

The planetary roller screw uses a linear contact method between the rollers and the screw and the nut. Compared with the point contact of the ball screw, the contact area is significantly increased. According to the Hertz contact theory, linear contact can more evenly distribute the load and reduce the stress per unit area, thereby significantly enhancing the capacity. Under the same outer diameter， the rated dynamic load of the planetary roller screw can reach 2-3 times that of the ball screw， or even higher.

2. Multi-point bearing structure

The rollers of the planetary roller screw are arranged circumferentially along the screw， usually with 6-20 rollers， and each roller forms multiple contact points with the screw and the nut. This multi-point bearing structure disperses the load onto more contact surfaces， further enhancing the overall bearing capacity， enabling the screw to withstand greater thrust.

3. Multi-threaded design

The screw of the planetary roller screw adopts multi-threaded design， without increasing the lead， it can accommodate more rollers， and at the same time improve the transmission efficiency and bearing capacity. The design of multi-threaded screw makes the contact between the rollers and the screw more stable during revolution， reducing local stress concentration， and helping to enhance the thrust.

4. High rigidity and impact resistance

The linear contact structure and multi-point bearing design of the planetary roller screw make it have higher axial rigidity and impact resistance. When bearing large thrust or impact loads， the deformation of the screw is smaller， enabling it to transfer thrust more stably and avoiding thrust loss due to deformation.

5. Optimized tooth profile design

The cross-section of the rollers' thread adopts Gothic arc tooth profile， which cooperates with the trapezoidal thread of the screw and the nut， forming an elliptical contact band close to a line. This tooth profile design has a "self-centering" effect， making the load distribution more uniform， and further enhancing the bearing capacity and thrust. In summary， the planetary roller screw achieves greater thrust than the ball screw through linear contact， multi-point bearing， multi-threaded design， high rigidity and optimized tooth profile design， making it more advantageous in heavy-load， high-precision and long-life application scenarios.

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