SMC CQE High Power Compact Cylinder: Specs, Part Numbers and CQ2 Replacement Checks
2026-11-04When a compact cylinder is short on force and the machine has no room for the next bore size up, the usual fix means redesigning the mounting. SMC’s CQE Series takes a different route: it keeps the compact cylinder envelope and raises theoretical output to about 1.5 times. This guide summarises the CQE specifications, how to read the part number, and what to check before swapping a CQ2 or CQS for a CQE, using SMC’s official catalogue (CAT.ES20-309) as the only source.
What makes the CQE different: a polygonal piston
A standard CQ2 uses a round piston. The CQE uses a polygonal piston that fills more of the same body, so each size has the piston area of the next larger round bore:
| CQE size | Piston area equivalent to | Same external dimensions as |
|---|---|---|
| 20 | ø25 | CQS series |
| 25 | ø32 | CQS series |
| 32 | ø40 | CQ2 series |
| 40 | ø50 | CQ2 series |
SMC’s headline comparison: at 0.5 MPa a size 32 CQE delivers 603 N on the extend stroke, against 402 N for an existing CQ2 ø32. SMC also notes that, thanks to the polygonal piston, the piston rod does not rotate during normal operation.
Two ways to use it
More force in the same space
For clamping or press-fitting stations (the applications SMC itself highlights) where a compact cylinder has run out of force, the CQE gives you the output of one bore size larger without changing the envelope.
Same force at lower pressure
If the existing force is enough, the CQE can reach it with a lower supply pressure. SMC’s catalogue gives these pairs:
| Theoretical output | CQE pressure needed | Existing CQ2 pressure needed |
|---|---|---|
| 157 N | Size 20: 0.32 MPa | ø20: 0.5 MPa |
| 245 N | Size 25: 0.34 MPa | ø25: 0.5 MPa |
| 402 N | Size 32: 0.33 MPa | ø32: 0.5 MPa |
| 628 N | Size 40: 0.35 MPa | ø40: 0.5 MPa |
For size 32 that is a 0.17 MPa drop in supply pressure, which is worth considering on lines where you want to run a lower-pressure branch. For the force calculation itself, including back pressure, see our cylinder bore sizing guide.
Key specifications
| Item | Specification |
|---|---|
| Sizes | 20, 25, 32, 40 |
| Action | Double acting, single rod |
| Operating pressure | 0.05 to 0.7 MPa |
| Ambient and fluid temperature | −10 to 60 °C (with auto switch) |
| Lubrication | Not required (non-lube) |
| Piston speed | 50 to 500 mm/s |
| Cushion | Rubber bumper |
| Allowable kinetic energy | 0.11 / 0.18 / 0.29 / 0.52 J (sizes 20 / 25 / 32 / 40) |
| Mounting | Through-hole / both ends tapped common (standard) |
| Port size | M5×0.8 (sizes 20, 25), Rc1/8 (sizes 32, 40) |
| Standard strokes | 5 to 50 mm in 5 mm steps; sizes 32 and 40 also 75 and 100 mm |
Theoretical output (N)
| Size | Direction | 0.3 MPa | 0.5 MPa | 0.7 MPa |
|---|---|---|---|---|
| 20 | IN | 124 | 206 | 288 |
| OUT | 147 | 245 | 343 | |
| 25 | IN | 196 | 327 | 458 |
| OUT | 220 | 366 | 513 | |
| 32 | IN | 316 | 526 | 737 |
| OUT | 362 | 603 | 844 | |
| 40 | IN | 488 | 814 | 1139 |
| OUT | 534 | 891 | 1247 |
These are theoretical values, so apply your usual load ratio margin when sizing.
Reading a CQE part number
SMC’s ordering example is CDQEB20-30-M9BW:
- CDQEB: CQE high power type; D means built-in magnet for auto switches; B means through-hole / both ends tapped common mounting (standard).
- 20: size (piston area equivalent to ø25).
- 30: stroke in mm.
- An optional M after the stroke selects a male rod end thread; without it the rod end has a female thread (standard).
- M9BW: auto switch model (omit for no switch). No suffix means two switches, S means one.
Compatible switches are the compact D-M9□ family (M9N, M9P, M9B, the M9□W types with 2-colour diagnostic indication, the water-resistant M9□A types, and their perpendicular-entry versions). Minimum stroke for switch mounting is 5 mm for one switch; for two switches it is 5 mm with D-M9□ and 10 mm with D-M9□W or D-M9□A.
Male rod end threads are M8×1.25 (size 20), M10×1.25 (size 25) and M14×1.5 (sizes 32 and 40).
Intermediate strokes and rod end changes
Strokes are available in 1 mm increments, built in one of two ways with different body lengths:
- Spacer-installed type (no suffix): a spacer inside a standard-stroke body. Range 1 to 49 mm for sizes 20 and 25, 1 to 99 mm for sizes 32 and 40. SMC’s example CDQEB32-57 uses a 75 mm stroke body with an 18 mm spacer, giving a B dimension of 108 mm.
- Exclusive body type (-XB10): a made-to-order body for the exact stroke, so the overall length is shorter. Range 6 to 49 mm for sizes 20 and 25, 6 to 99 mm for sizes 32 and 40. The same 57 mm stroke as CDQEB32-57-XB10 has a B dimension of 90 mm.
Rod end shapes can be changed through SMC’s Simple Specials system (-XA□); the catalogue lists which symbols and dimension limits apply to each size.
Before replacing a CQ2 or CQS with a CQE
- Check which series you are replacing. Sizes 32 and 40 share the CQ2’s external dimensions, but sizes 20 and 25 match the CQS series, not the CQ2. If the existing cylinder is a CQ2 ø20 or ø25, compare the dimension tables before assuming it will bolt in.
- Check the machine can take the extra force. At the same pressure the output rises by about 1.5 times, so review the strength of the fixture, workpiece and mounting.
- Check kinetic energy and lateral load. The CQE has rubber bumpers only; use the allowable kinetic energy above and the catalogue’s lateral load curve for your stroke.
- Respect the rod end tightening limits. SMC asks you to tighten workpieces with the rod fully retracted, holding the rod flats, within 1.7 / 1.7 / 1.9 / 2.0 N·m for sizes 20 / 25 / 32 / 40.
- Re-check speed settings. A larger piston area moves more air per stroke, so existing flow control settings may need adjusting. See our guide to meter-out vs meter-in speed control.
Maintenance: replacing the seals
According to SMC, seal replacement needs no special tools: the stop ring comes out with a watchmaker’s screwdriver or similar. Seal kits are CQEB20-PS, CQEB25-PS, CQEB32-PS and CQEB40-PS, each containing the piston seal, rod seal, tube gasket and stop ring. Grease is not included; order grease pack GR-S-010 (10 g) separately. Avoid putting heavy force on the stop ring during maintenance, as it can deform.
FAQ
Is the CQE a drop-in replacement for the CQ2?
Sizes 32 and 40 have the same external dimensions as the CQ2; sizes 20 and 25 match the CQS. Whether it is a direct swap also depends on ports, rod end thread, switch mounting and how the extra force affects your machine.
Does the CQE have an air cushion?
The catalogue lists a rubber bumper as the cushion type and gives no air cushion option.
What pressure range does it work in?
0.05 to 0.7 MPa. When running at reduced pressure, use the theoretical output table to confirm the force you actually need.
Which sizes are available?
The current catalogue lists sizes 20, 25, 32 and 40; sizes 25 and 40 were added later.
Need help matching a part number?
Send us the full model of your current cylinder, the stroke, the mounting style and your operating pressure, and we will help you check it: doskee@dustry.ltd. You may also find our ISO 6432 mini cylinder cross reference useful.
Sources: SMC catalogue “Compact Cylinder / High Power Type CQE Series” CAT.ES20-309 (features, How to Order, Specifications, Intermediate Strokes, Simple Specials, Specific Product Precautions); SMC new products page for the CQE Series. Always confirm details against the manufacturer’s latest official documentation.