Bosch Roller Screw Calculator
Estimate Bosch PLSA life and verify fit limits.
Published 7 October 2026 · Last reviewed 7 October 2026
Open life estimatorKey Engineering Takeaways
Published PLSA family maxima
Bosch Rexroth publishes maximum ratings of 544 kN dynamic and 1,496 kN static for its planetary screw assembly family. These are family maxima, not ratings for every size or part number.
Match the complete interface
The PLSA family spans 20–75 mm nominal diameters and 5–20 mm leads. A shared diameter or lead does not establish interchangeability; verify the exact nut, mounting, preload, and end machining.
Speed & Accuracy Limits
Bosch publishes a family d₀ × n maximum of 150,000 and speeds up to 50 m/min. PLSA accuracy grades include T5, T7, and T9; the applicable limit depends on the specific configuration.
Confirm lead time by configuration
Published family data does not establish stock status or delivery dates. Request a current quote for the exact assembly and assess any alternative against its own verified drawings and ratings.
Bosch PLSA Nominal Life Estimator
Estimate nominal service life from the dynamic rating and equivalent load for a specific catalog configuration. This is a screening calculation, not a machine safety or selection check.
Use the catalog rating C and equivalent load Fm for the selected part and duty cycle. The calculation assumes a constant equivalent load and does not account for static safety, buckling, critical speed, preload details, lubrication, temperature, or reliability adjustments.
Enter a catalog rating, equivalent load, lead, diameter, and average speed to see a preliminary estimate.
How the nominal life estimate works
The estimator uses the PLSA catalog relationship for nominal service life. Its result is only as useful as the entered catalog rating and equivalent load.
L = (C / Fm)3 × 106 revolutions
Lh = L / (nm × 60)
- C
- Dynamic rating for the exact catalog configuration.
- Fm
- Equivalent dynamic axial load for the duty profile.
- nm
- Average screw speed in revolutions per minute.
For changing loads and speeds, derive Fm and nm using the catalog procedure. The estimator does not calculate those values from a motion profile or add application correction factors.
Formula source: Bosch Rexroth screw assemblies catalog R999001185/2025-11, page 271. The catalog calculates equivalent loads separately for changing duty profiles on pages 272–273.
Load Distribution: Bosch Roller Screw vs Ball Screw
Conceptual contact geometry only; this diagram is not to scale and does not compare rated load or life. Select using the manufacturer's ratings for the exact assembly.
Published PLSA Family Envelope
These are product-family ranges and maxima published by Bosch Rexroth, not values for every size or a substitute for checking a configured part. Per-size ratings must be taken from the current catalog.
| Measure | Published family value | How to use it |
|---|---|---|
| Diameter / lead | 20–75 mm / 5–20 mm | Confirm that the exact pair exists in the catalog. |
| Accuracy grades | T5, T7, T9 | Choose to match the application tolerance. |
| Dynamic load rating C | Up to 544 kN | Use the rating for the exact model in the life estimator. |
| Static load rating C₀ | Up to 1,496 kN | Check separately against peak and shock loads. |
| d₀ × n | Up to 150,000 | Family maximum; the selected assembly may be lower. |
| Linear speed | Up to 50 m/min | Family maximum; verify for the actual lead and duty. |
Source: Bosch Rexroth screw drives overview and PLSA catalog R999001185. Values checked 7 October 2026; the English catalog edition is dated 1 November 2025.
Evidence Basis & Boundaries
Calculation boundaries and data sourcing for our roller screw evaluations.
| Source | Application | Known Boundary |
|---|---|---|
| Bosch Rexroth screw drives overviewAccessed 2026-10-07 | Lists the PLSA family ranges, accuracy grades, and maximum published dynamic, static, and d₀ × n values. | Family maxima are not per-size ratings or a substitute for checking a configured part. |
| Bosch Rexroth PLSA product release2024-06-24 | Confirms the PLSA family speed up to 50 m/min and dynamic load capacity up to 544 kN. | The release describes family maxima and does not give operating limits for every configuration. |
| Bosch Rexroth screw assemblies catalog R999001185Active English edition dated 2025-11-01 | Primary source for configuration-specific ratings, selection, mounting, and the PLSA nominal service-life method. | Use the rating and equivalent load for the exact part and duty profile; this page does not reproduce the full catalog calculation. |
| ISO 3408-5:2006ISO page checked 2026-10-07 | Defines load-rating and operational-life calculation schemes for ball screws. It is not cited here as the PLSA life-calculation method. | The standard title and scope refer to ball screws; use the Bosch PLSA catalog for planetary screw assembly calculations. |
Common Retrofit Risks
- Incorrect lead accuracy specification: Confirm the required accuracy class and its tolerance over the application travel. Bosch PLSA family grades are T5, T7, and T9; do not assume a substitute matches without a measured or documented tolerance.
- End-journal machining mismatch: Compare the end machining drawing, bearing journals, and coupling interface. A nominal screw size alone cannot confirm bearing or motor fit.
- Lubrication interface or interval mismatch: Confirm port location, lubricant, quantity, and relubrication interval against the selected nut and machine duty cycle before connecting an existing system.
- Treating family speed maxima as a safe operating point: The published 150,000 d₀ × n and 50 m/min values are family maxima, not simultaneous or model-specific approvals. Check the exact part and application in the current catalog or selector.
- Operating Outside Temperature Boundaries: Temperature, lubrication, contamination, and duty cycle affect service life. Confirm the permitted conditions for the exact assembly and lubricant with the manufacturer.
Frequently Asked Questions
What makes a Bosch roller screw different from a ball screw?
A Bosch PLSA planetary screw assembly uses threaded rollers between the screw and nut, while a ball screw uses recirculating balls. The contact geometry and catalog ratings differ, so compare the manufacturers’ ratings and application limits for the exact sizes rather than assuming a fixed load or life multiplier.
Can I calculate the exact life of a Bosch PLSA?
No. The estimator applies the nominal catalog relationship to the entered dynamic rating and equivalent axial load. A correct Fm must represent the operating load profile; preload, mounting, lubrication, temperature, contamination, and reliability requirements need separate consideration.
Are there direct drop-in equivalents for Bosch roller screws?
A matching diameter and lead are not enough to establish a drop-in replacement. Check the full part number, nut dimensions, flange or cylindrical mounting, preload, lubrication interface, end machining, accuracy, and load/speed ratings against drawings.
How do I compare a non-OEM alternative?
Compare current quotations and documented technical data for the exact configuration. Ask for dimensional drawings, dynamic and static ratings, accuracy, preload method, lubrication details, and delivery date; validate the substitute in the application before release.
What should I provide for an engineering or sourcing review?
Send the full Bosch Rexroth part number, assembly and end-machining drawings, nut style, required accuracy, load/speed duty cycle, mounting details, lubrication conditions, and target delivery date. This lets the supplier verify fit and rating rather than infer them from diameter and lead.
Looking for a Bosch Roller Screw Alternative?
Send the Bosch part number, drawings, mounting details, and duty cycle. Our engineering team can review a proposed alternative against those requirements and identify any items that still need verification. Delivery time is confirmed by quote.
Inquiry Email
Include force, stroke, speed, duty cycle, life target, quantity, and delivery country.
Send actuator specs to [email protected] or WhatsApp WhatsApp Engineering Support for an engineering review.