IP Library › Granted Patent US 12662996
Granted Patent B2
US 12662996 · App. 19/035,638 · Granted Jun 23, 2026

Double acting two stage piston type pump

Inventors: Simon Warner (Pontefract, GB); Paul Wellings (Pontefract, GB); Rahman Basheer (Chennai, IN)
Assignee: ZF CV Systems Europe BV
F04B35/01F04B25/005F04B53/147F04B37/14
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 12662996
App. No.
19/035,638
Granted
Jun 23, 2026
Kind
B2
Abstract

A double acting two stage piston type pump includes a pump housing having a piston arrangement connected to a driving shaft which, when driven, sets the piston arrangement into movement. The piston arrangement has at least two primary stage pistons, the primary stage pistons being slidably seated in respective primary stage cylinders formed in the pump housing. The piston arrangement also includes at least two secondary stage pistons slidably seated in respective secondary stage cylinders formed in the primary stage pistons. The primary stage pistons and the secondary stage pistons are mounted on, and directly driven by, eccentrics mounted on the driving shaft.

Claims (40)

1 . A piston type pump comprising:

a pump housing having a piston arrangement connected to a driving shaft which, when driven, sets said piston arrangement into movement;

said piston arrangement including a first primary stage piston, a first secondary stage piston, a second primary stage piston, and a second secondary stage piston;

said first primary stage piston being slidably seated in a first primary stage cylinder formed in said pump housing;

said first secondary stage piston being slidably seated in a first secondary stage cylinder formed in said first primary stage piston;

said second primary stage piston being slidably seated in a second primary stage cylinder formed in said pump housing;

said second secondary stage piston being slidably seated in a second secondary stage cylinder formed in said second primary stage piston;

said driving shaft including a first eccentric and a second eccentric which are phase shifted by 180°;

said first secondary stage piston including a first secondary stage piston rod and said second secondary stage piston including a second secondary stage piston rod;

said first primary stage piston and said second secondary stage piston rod being configured to be mounted on and directly driven by said second eccentric; and,

said first secondary stage piston rod and said second primary stage piston being mounted on, and directly driven by, said first eccentric, wherein said driving shaft includes a stud, said first eccentric and said second eccentric being mounted on said stud, and said driving shaft and said stud are separate components.

2 . The piston type pump of claim 1 , wherein at least one of said first eccentric and said second eccentric is fixedly mounted on said stud.

3 . The piston type pump of claim 1 , wherein at least one of said first eccentric and said second eccentric is in threaded engagement with said stud.

4 . The piston type pump of claim 1 , wherein said first eccentric is provided with a first torque-transmitting and aligning arrangement configured to engage in a predetermined angular way with a second torque-transmitting and aligning arrangement provided on said second eccentric.

5 . The piston type pump of claim 4 , wherein said first torque-transmitting and aligning arrangement provided on said first eccentric has a first protrusion and a second protrusion; and, said second torque-transmitting and aligning arrangement provided on said second eccentric has at least a third protrusion configured to fit with said first protrusion and said second protrusion provided on said first eccentric.

6 . The piston type pump of claim 5 , wherein said third protrusion is coaxial to a bore for insertion of said stud.

7 . The piston type pump of claim 1 , further comprising a nut disposed on said stud; and, said nut being in threaded engagement with said stud and in contact force transmitting engagement with said second eccentric.

8 . A vehicle comprising the piston type pump of claim 1 .

9 . The vehicle of claim 8 , wherein the vehicle is a passenger car or a commercial vehicle.

10 . A piston type pump comprising:

a pump housing having a piston arrangement connected to a driving shaft which, when driven, sets said piston arrangement into movement;

said piston arrangement including a first primary stage piston, a first secondary stage piston, a second primary stage piston, and a second secondary stage piston;

said first primary stage piston being slidably seated in a first primary stage cylinder formed in said pump housing;

said first secondary stage piston being slidably seated in a first secondary stage cylinder formed in said first primary stage piston;

said second primary stage piston being slidably seated in a second primary stage cylinder formed in said pump housing;

said second secondary stage piston being slidably seated in a second secondary stage cylinder formed in said second primary stage piston;

said driving shaft including a first eccentric and a second eccentric which are phase shifted by 180°;

said first secondary stage piston including a first secondary stage piston rod and said second secondary stage piston including a second secondary stage piston rod;

said first primary stage piston and said second secondary stage piston rod being configured to be mounted on and directly driven by said second eccentric; and,

said first secondary stage piston rod and said second primary stage piston being mounted on, and directly driven by, said first eccentric, wherein said driving shaft includes a cap screw; and, said first eccentric and said second eccentric are mounted on said cap screw, wherein said driving shaft and said cap screw are separate components.

11 . The piston type pump of claim 10 , wherein at least one of said first eccentric and said second eccentric is in threaded engagement with said cap screw.

12 . The piston type pump of claim 10 , wherein said second eccentric is provided with a flange configured to fit with a recess provided on said first eccentric.

13 . The piston type pump of claim 12 further comprising a pin configured to fixedly secure said flange provided on said second eccentric with said recess provided on said first eccentric.

14 . A vehicle comprising the piston type pump of claim 10 .

15 . A method for mounting a piston type pump, the method comprising:

mounting a first secondary stage piston rod and a second primary stage piston on a first eccentric;

interference mounting a driving shaft into the first eccentric;

inserting the first secondary stage piston rod, the second primary stage piston, the first eccentric and the driving shaft into a pump housing;

mounting a second eccentric on the driving shaft and aligning it with the first eccentric; and,

mounting the first primary stage piston and the second secondary stage piston rod on the second eccentric, wherein said driving shaft includes a stud, said first eccentric and said second eccentric being mounted on said stud, and said driving shaft and said stud are separate components or wherein said driving shaft includes a cap screw; and, said first eccentric and said second eccentric are mounted on said cap screw, wherein said driving shaft and said cap screw are separate components.