Double-piston compressor having a sliding block producing a stroke curve that deviates from a sinusoidal stroke curve

Patent metadata

Field	Value
Publication number	US-11732702-B2
Application number	US-202117342556-A
Country	US
Kind code	B2
Filing date	Jun 9, 2021
Priority date	Dec 8, 2015
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A compressor includes a low pressure stage having a low pressure cylinder, a high pressure stage having a high pressure cylinder, a low pressure piston guided in an axially movable manner in the low pressure cylinder, a high pressure piston guided in an axially movable manner in the high pressure cylinder, a piston rod rigidly connecting the low pressure piston and the high pressure piston, and a sliding block guide. The sliding block guide includes a recess arranged in the piston rod and further includes two substantially parallel sliding block tracks. One of the sliding block tracks has an arc-shaped indentation in a central portion. The sliding block tracks are constructed and such that a movement of the low pressure piston and of the high pressure piston follows a piston stroke curve that deviates from a regular sinusoidal stroke curve.

First claim

What is claimed is:

1. A two-stage compressor of a compressed air supply device, the two-stage compressor comprising:
a low pressure stage having a low pressure cylinder;
a high pressure stage having a high pressure cylinder;
a low pressure piston guided in an axially movable manner in the low pressure cylinder;
a high pressure piston guided in an axially movable manner in the high pressure cylinder;
a piston rod rigidly connecting the low pressure piston and the high pressure piston; and
a sliding block guide, the sliding block guide having a recess arranged in the piston rod, the sliding block guide having two substantially parallel sliding block tracks, one of the sliding block tracks having an arc-shaped indentation in a central portion,
wherein the cylinder of the low pressure stage and the cylinder of the high pressure stage are arranged radially opposite with respect to an axis of rotation of a drive shaft,
wherein the low pressure piston and the high pressure piston are connected to the drive shaft via the sliding block guide,
wherein the two sliding block tracks are aligned in a plane perpendicular to the axis of rotation of the drive shaft,
wherein the drive shaft has a drive interface configured to engage with the recess, an axis of the drive interface being arranged axially parallel to the axis of rotation of the drive shaft, the drive interface being secured on the drive shaft with an eccentricity, and
wherein the sliding block tracks of the sliding block guide are constructed and arranged such that, during operation of the two-stage compressor, a movement of the low pressure piston and of the high pressure piston follows a piston stroke curve that deviates from a regular sinusoidal stroke curve having an amplitude corresponding to the eccentricity of the drive interface.

2. The two-stage compressor as claimed in claim 1 , wherein the arc-shaped indentation is a circular-arc-shaped indentation.

3. The two-stage compressor as claimed in claim 2 , wherein a radius and a depth of the circular-arc-shaped indentation are dimensioned such that a stroke height of the piston rod when the drive interface passes through the indentation is kept constant.

4. The two-stage compressor as claimed in claim 1 , wherein the drive interface includes a crank pin, the crank pin being secured on the drive shaft at a position radially spaced by the eccentricity from the axis of rotation of the drive shaft.

5. The two-stage compressor as claimed in claim 4 , wherein the drive interface further includes a rolling bearing having an inner ring and an outer ring, the inner ring of the rolling bearing lying on the crank pin and the outer ring of the rolling bearing rollably guided on the two parallel sliding block tracks.

6. The two-stage compressor as claimed in claim 4 , wherein the drive interface further includes a rolling bearing and a slide bearing ring,
wherein the rolling bearing has an inner ring and an outer ring, the inner ring of the rolling bearing lying on the crank pin and the outer ring of the rolling bearing lying against an interior of the slide bearing ring, and
wherein the slide bearing ring has an exterior surface that is guided on the two parallel sliding block tracks.

7. The two-stage compressor as claimed in claim 1 , wherein the piston stroke curve and the regular sinusoidal stroke curve have a same stroke width.

8. The two-stage compressor as claimed in claim 1 , wherein the amplitude of the piston stroke curve corresponds to a stroke height of the low pressure piston and of the high pressure piston.

9. The two-stage compressor as claimed in claim 1 , wherein, in the central portion, the sliding block track having the arc-shaped indentation in the central portion is not linear to the other sliding block track of the two sliding block tracks.

10. The two-stage compressor as claimed in claim 9 , wherein the other of the two sliding block tracks includes a linear portion, the linear portion having a length of at least twice the eccentricity and at most a maximum length of the recess.

11. The two-stage compressor as claimed in claim 1 , wherein only one of the sliding block tracks has an arc-shaped indentation in a central portion.

12. The two-stage compressor as claimed in claim 11 , wherein each of the sliding block tracks have a straight portion, the straight portion of one of the sliding block tracks being parallel to the straight portion of the other of the sliding block tracks.

13. The two-stage compressor as claimed in claim 1 , wherein the movement of the low pressure piston and of the high pressure piston follows a piston stroke curve that deviates from the regular sinusoidal stroke curve in that it includes a reduced amplitude in at least one stroke of each of the pistons.

14. The two-stage compressor as claimed in claim 13 , wherein the piston stroke curve that deviates from the regular sinusoidal stroke curve has a constant displacement value over an interval of rotation of the drive shaft.

Assignees

• Zf Cv Systems Hannover Gmbh
• Zf Cv Systems Europe Bv

Inventors

• Meissner Frank
• Seeger Marco

Classifications

• F04B25/005 Primary

  with two cylinders · CPC title

• F04B9/04

  the means being cams, eccentrics or pin-and-slot mechanisms · CPC title

• F04B27/02

  having cylinders arranged oppositely relative to main shaft · CPC title

• F04B27/0428

  Arrangements for pressing or connecting the pistons against the actuated cam · CPC title

• F04B53/144

  Adaptation of piston-rods · CPC title