Pump bushings
A pump bushing is lubricated by whatever the pump moves: hydraulic oil in a gear pump, water in a circulating pump, a process fluid in a chemical pump. The bearing material has to run on that fluid, resist it and not contaminate it, at speeds well above those of a greased pivot.
- 12 m/sJBM-BP line speed, CuPb10Sn10
- ≥ 150 MPaBearing-layer shear strength
- 115–150 HBJBM-AP side plate hardness
- > 3 m/sPTFE composite in the fluid
Pump bushings run at shaft speed in the pumped fluid. In hydraulic gear pumps the gear-shaft bearings are steel-backed bimetal bushes (JBM-BP: CuPb10Sn10, CuPb7Sn7Zn3 or CuSn6.5P on steel, up to 10–12 m/s line speed) and the axial faces are aluminium-alloy side plates (JBM-AP). PTFE composite bushings (JBM-10 / JBM-1T) serve as fluid-lubricated bushings in gear, vane and small piston pumps. Water and process pumps use bronze, graphite-plugged bronze with PTFE + MoS₂ plugs, or stainless-backed composite.
- Gear-pump bearing bushes JBM-BP: bearing-alloy layer shear strength ≥ 150 MPa, maximum line speed 12 m/s (CuPb10Sn10) or 10 m/s (CuPb7Sn7Zn3, CuSn6.5P), 60–90 HB, on SAE1010 / Q235B / Q345B steel
- Gear-pump side plates JBM-AP: aluminium alloy 2010 / 2014, surface hardness 115–150 HB, friction ≤ 0.1
- PTFE composite pump bushings run in the fluid at > 3 m/s; bronze or stainless backs for water and chemicals
- Water and seawater pumps: graphite-plugged bronze with PTFE + MoS₂ plugs and a stainless shaft; tin and aluminium bronze
- Bushing MFG supplies the bearing parts; pump housings, gears and seals are not its products
Bushings for pumps
Gear-pump bushes and side plates for hydraulic pumps; PTFE composite, bronze and graphite bronze for whatever else the pump moves.
Bimetal bushings
Steel-backed gear-pump bearing bushes: CuPb10Sn10, CuPb7Sn7Zn3 or CuSn6.5P linings.
JBM-BP
PTFE composite bushings
Fluid-lubricated bushings for gear, vane and small piston pumps; bronze or stainless backs.
JBM-10 / 1T
Graphite bronze bushings
PTFE + MoS₂ plugs for water and seawater pumps against a stainless shaft.
JBM-650
Bronze bushings
Tin and aluminium bronze for water and process pumps with a lubricating fluid.
JBM-600
Gear-pump bearing bushes and side plates
In an external gear pump each gear shaft runs in two bushes pressed into the body or the bearing blocks, lubricated by the hydraulic oil at the pump's own pressure and speed, and the gear faces run against side plates that seal the axial gap. The bushes are steel-backed bimetal bearings: a bearing-alloy layer sintered onto a steel back, with the oil film doing the work at 10–12 m/s line speed. The side plates are aluminium alloy, hard enough to resist the gear faces and light enough to float on the pressure balance.
| JBM-BP bearing-alloy layer | Shear strength | Maximum line speed | Hardness |
|---|---|---|---|
| CuPb10Sn10 | ≥ 150 MPa | 12 m/s | 60–90 HB |
| CuPb7Sn7Zn3 | ≥ 150 MPa | 10 m/s | 60–90 HB |
| CuSn6.5P | ≥ 150 MPa | 10 m/s | 60–90 HB |
Owner-approved JBM-BP table. Steel backings: SAE1010 (≥ 265 MPa, 90–130 HB), Q235B (370–500 MPa, 90–130 HB), Q345B (490–675 MPa, 110–170 HB); the pairing of alloy and backing follows the part drawing.
JBM-AP side plates
Aluminium-alloy plates that take the axial thrust of the gears and seal the tooth ends.
| JBM-AP material label | Surface hardness | Coefficient of friction | Yield strength | Elongation |
|---|---|---|---|---|
| 2010 | 115–135 HB | ≤ 0.1 | ≥ 150 | ≥ 12 |
| 2014 | 125–150 HB | ≤ 0.1 | ≥ 215 | ≥ 13 |
Owner-supplied labels and values as transcribed; the yield-strength unit and test conditions are stated on the controlled drawing.
Fluid-lubricated composite bushings
Where a pump bushing is not a bimetal bearing block, it is usually a steel-backed PTFE composite bushing running in the fluid: JBM-10 or the pump variant JBM-1T. The oil or water lubricates and cools the PTFE layer, so the speed limit rises from 2 m/s dry to more than 3 m/s and the 250 N/mm² static rating is unchanged; the bushing tolerates dry starts and brief cavitation that would score a plain bronze bush. For water, chemicals and food the same layer is supplied on a bronze back (JBM-1B) or a stainless 304 / 316 back (JBM-1S), and the running layer is chosen for the fluid.
Water and process pumps
Water is a poor lubricant and washes grease out. Bushings for circulating, drainage, marine and turbine pumps are tin bronze or aluminium bronze on a stainless shaft, graphite-plugged bronze with the PTFE + MoS₂ plug formulated for water and seawater, or stainless-backed PTFE composite. Sand and silt in the water call for a hard shaft and a bushing that does not embed grit in a soft layer, which favours the plugged bronze.
What to put in the enquiry
Shaft diameter and speed, housing bore and length, pressure at the bearing, the fluid and its temperature, contamination, and quantity; for gear-pump parts the drawing of the bush or plate. Bushing MFG supplies the bearing parts to pump manufacturers and rebuilders; pump housings, gears, shafts and seals are not our products.
Frequently asked questions
What bearings are in a hydraulic gear pump?
Steel-backed bimetal bushes (bearing alloy on steel) in which the gear shafts run in the hydraulic oil, and aluminium-alloy side plates against the gear faces. JBM-BP and JBM-AP are Bushing MFG's parts for these positions.
Can a PTFE bushing run in oil or water?
Yes. The fluid lubricates and cools it; speed rises above 3 m/s and load capacity is unchanged. Bronze or stainless backs are used in water and chemicals.
Which bushing for a seawater pump?
Graphite-plugged bronze with the PTFE + MoS₂ plug and a stainless or hard-chromed shaft, aluminium bronze, or stainless-backed PTFE composite. Plain greased bronze loses its grease to the water.
How fast can a gear-pump bush run?
The JBM-BP bearing alloys are rated to 12 m/s (CuPb10Sn10) and 10 m/s (CuPb7Sn7Zn3, CuSn6.5P) line speed in oil, per the approved table; the combination with pressure and temperature follows the pump design.
Do you make complete gear pumps?
No. Bushing MFG makes the bearing bushes and side plates; housings, gears, shafts and seals are the pump manufacturer's parts.
Send the joint, not just the part.
Pin diameter, load, motion, lubrication and environment: our engineers reply within 12 hours with a material, a size and a quotation. Free samples, no minimum order.