Piston pump

• US 6,217,300 B1
• Filed: 01/19/2000
• Issued: 04/17/2001
• Est. Priority Date: 01/20/1999
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schuller, Wolfgang, Eckstein, Ursula
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): FASTOVSKY, LEONID M
• Application Number:
  US09/487,320
• Time in Patent Office: 454 Days
• Field of Search: 92/78, 303/116.4, 417/454, 417/549, 417/541
• US Class Current: 417/549
• CPC Class Codes: B60T 8/4031 Pump units characterised by their construction or mounting pump units in combination with valve blocks B60T8/36
• CPC Class Codes: F04B 53/166 Cylinder liners
• CPC Class Codes: F04B 53/20 Filtering

Abstract

A piston pump with a piston that is displaceable in a bush. In order to keep the piston in the bush for retention therein a hollow-cylindrical filter, mounted on the bush, with yielding fingers that engage a groove of the piston keep the piston in the bush until the bush has been inserted into a pump housing.

Claims

1. A piston pump, comprising a piston that is driven to execute a reciprocating stroke motion and is axially displaceably received, over at least part of its length, in a bush that is inserted into a pump housing, and a retention means for the piston is mounted on the bush, the retention means engages an undercut of the piston, and the undercut is made on the piston inside a piston circumference, the piston pump (10) has a tubular filter (80);

the filter (80) is mounted, lengthening the bush (12), on an open face end of the bush (12);

the retention means (92) is embodied to yield in the radial direction and automatically comes into engagement with the undercut (96) of the piston (20);

the retention means (92) is mounted on the filter (80); and

the filter (80) is mounted in clamping fashion on the bush (12).

2. The piston pump according to claim 1, in which the retention means (92) is integral with the filter (80).

3. The piston pump of claim 1, in which the filter (80) and the bush (12) are adjoined together in the manner of a tight fit, and that the filter (80) for the clamping fastening to the bush (12) has a press fit relative to the bush (12).

4. The piston pump of claim 1, in which the piston (20), over part of its length, protrudes axially out of the bush (12) and both inside the bush (12) and outside the bush (12), has a weighted diameter that corresponds to an inside diameter of the bush (12).

5. The piston pump of claim 1, in which the undercut (96) of the piston (20) is formed by a groove side (96) of a groove (34) made encompassing the circumference of the piston.

6. The piston pump of claim 1, in which the retention means (92) has a curved, yielding finger (92), extending inward relative to a circumferential direction, on an inside of the bush (12).

7. The piston pump of claim 1, in which the filter (80) forms a guide for the piston (20), which keeps the piston (20) oriented axially, or at least approximately axially, in the bush (12).