PISTON HAVING TWO CENTER BORES WITH DIFFERENT SIZES

Abstract

A piston may include a first center bore and a second center bore configured to receive a piston pin. The first center bore and the second center bore may have different diameters. An axis of the first center bore may extend parallel to an axis of the second center bore.

Claims

1. A piston, comprising: a first center bore and a second center bore configured to receive a piston pin, wherein: the first center bore and the second center bore have different diameters; and an axis of the first center bore extends parallel to an axis of the second center bore.

2. The piston as claimed in claim 1, further comprising the piston pin, wherein, in a fitted state, the piston pin is arranged to form a positive interlock in the first center bore and the second center bore.

3. The piston as claimed in claim 2, wherein the piston pin has at least two different outside diameters.

4. The piston as claimed in claim 1, wherein the axis of the first center bore is offset from the axis of the second center bore in a stroke direction.

5. The piston as claimed in claim 1, wherein the axis of the first center bore is offset from the axis of the second center bore in a direction extending transversely to a stroke direction.

6. The piston as claimed in claim 1, wherein the axis of the first center bore is offset from the axis of the second center bore in a stroke direction and in a direction extending transversely to the stroke direction.

7. The piston as claimed in claim 1, wherein the axis of the first center bore and the axis of the second center bore are offset from one another by an offset distance of 0.2 mm to 3 mm.

8. A piston pin for the piston as claimed in claim 1, comprising: a first cylindrical longitudinal end area having a first outside diameter and a first cylinder axis; a second cylindrical longitudinal end area having a second outside diameter and a second cylinder axis; wherein the first outside diameter and the second outside diameter are different from one another; and wherein the first cylinder axis and the second cylinder axis are offset from one another.

9. The piston pin as claimed in claim 8, wherein the first cylinder axis and the second cylinder axis are offset from one another by an offset distance of 0.2 mm to 3 mm.

10. An oil-free compressor, comprising a piston as claimed in claim 1.

11. The oil-free compressor as claimed in claim 10, further comprising a piston pin including: a first cylindrical longitudinal end area having a first outside diameter; and a second cylindrical longitudinal end area having a second outside diameter.

12. The oil-free compressor as claimed in claim 11, wherein: the first outside diameter of the piston pin substantially corresponds to a diameter of the first center bore; and the second outside diameter of the piston pin substantially corresponds to a diameter of the second center bore.

13. The oil-free compressor as claimed in claim 10, further comprising a piston pin including: a first cylindrical longitudinal end area having a first cylinder axis; a second cylindrical longitudinal end area having a second cylinder axis; and the first cylinder axis and the second cylinder axis are offset from one another.

14. The oil-free compressor as claimed in claim 13, wherein the axis of the first center bore is offset from the axis of the second center bore.

15. The oil-free compressor as claimed in claim 14, wherein an offset between the axis of the first center bore and the axis of the second center bore is complimentary to an offset between the first cylinder axis and the second cylinder axis.

16. The oil-free compressor as claimed in claim 14, wherein: the axis of the first center bore is offset from the axis of the second center bore by an offset distance; the first cylinder axis is offset from the second cylinder axis by the offset distance; and the offset distance is 0.2 mm to 3 mm.

17. The oil-free compressor as claimed in claim 10, further comprising a piston pin including: a first cylindrical longitudinal end area having a first outside diameter and a first cylinder axis; and a second cylindrical longitudinal end area having a second outside diameter and a second cylinder axis; wherein the first cylinder axis and the second cylinder axis are offset from one another; and wherein the axis of the first center bore and the axis of the second center bore are offset from one another.

18. The oil-free compressor as claimed in claim 17, wherein: the first outside diameter of the piston pin substantially corresponds to a diameter of the first center bore; the second outside diameter of the piston pin substantially corresponds to a diameter of the second center bore; and an offset between the axis of the first center bore and the axis of the second center bore is complimentary to an offset between the first cylinder axis and the second cylinder axis such that the piston pin is only insertable into the first center bore and the second center bore when the piston pin is arranged in a fitting position.

19. The oil-free compressor as claimed in claim 18, wherein the piston pin is disposed in the fitting position and is arranged within the first center bore and the second center bore forming a positive interlocking connection therewith.

20. The piston as claimed in claim 1, wherein: the axis of the first center bore is a central longitudinal axis of the first center bore; and the axis of the second center bore is a central longitudinal axis of the second center bore.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The figures schematically show:

[0021] FIG. 1 shows a sectional representation of a piston according to the invention,

[0022] FIG. 2 shows a sectional representation of the piston according to the invention transversely to the stroke direction,

[0023] FIG. 3 shows a front view of a piston pin according to the invention,

[0024] FIG. 4 shows a longitudinal sectional representation of the piston pin according to the invention.

DETAILED DESCRIPTION

[0025] According to FIGS. 1 and 2 a piston 1 comprises a first center bore 2 and a second center bore 3 for receiving a piston pin 4. The first center bore 2 and the second center bore 3 have different diameters A, B. An axis 5 of the first center bore 2 runs parallel to an axis 6 of the second center bore 3. A stroke direction 7 of the piston 1 is represented by the direction of the arrow in FIG. 1. As is illustrated in FIG. 1, the axis 5 is offset by an offset V relative to the axis 6 in the stroke direction 7. Without departing from the scope of the present invention, the axis 5 may be offset by an offset V relative to the axis 6 transversely to the stroke direction 7. It is equally possible for the axis 5 to be offset by an offset V in the stroke direction 7 and transversely to the stroke direction 7. Since the axis 5 and the axis 6 in FIGS. 1 and 2 are offset only in the stroke direction 7, the offset V can be represented only in FIG. 1, since the axis 5 and the axis 6 lie parallel one on top of the other and for this reason can be represented only as one line in FIG. 2. In FIG. 2 an offset V can be represented only if the axis 5 and the axis 6 have an offset V transversely to the stroke direction.

[0026] In the assembled state, the piston pin 4, not represented in FIGS. 1 and 2, is arranged to form a positive interlock in the first center bore 2 and in the second center bore 3.

[0027] According to FIGS. 3 and 4 the piston pin 4 has a first outside diameter 10 on a first cylindrical longitudinal end area 8 and a second outside diameter 11 on a second cylindrical longitudinal end area 9. The first outside diameter 10 and the second outside diameter 11 are of different sizes. As is illustrated in FIGS. 3 and 4, the cylinder axes 12 are arranged offset relative to one another by an offset V. Without departing from the scope of the present invention, the cylinder axes 12 may be offset relative to one another in a manner different from that represented in FIGS. 3 and 4. The offset of the cylinder axes 12 (cf. FIGS. 3 and 4) here must be complementary to the relative offset V of the axis 5 of the first center bore 2 and the axis 6 of the second center bore 3 (cf. FIGS. 1 and 2.). The cylinder axes 12 in FIG. 3 run into the viewing plane and are accordingly represented as points.

[0028] The piston according to the invention 1 and the piston pin 4 according to the invention are in particular used in an oil-free compressor 13 not represented in FIGS. 1 to 4. The piston pin 4 serves to connect a connecting rod to the piston 1. The connecting rod is introduced into the piston 1 and the piston pin 4 is then likewise introduced into the piston 1, in such a way that the connecting rod is fixed in the piston 1 by the piston pin 4 and the piston pin 4 is supported by positive interlock in the first center bore 2 and in the second center bore 3.

[0029] The offset V serves to prevent a rotation of the piston pin 4 in the piston 1 by virtue of a geometric shaping, so that the wearing of the piston pin 4 and the piston 1 during operation of the compressor 13 is at least reduced. A rotation of the piston pin 4 in the piston 1 leads to a gentle jamming of the piston pin 4 in the piston 1. Without departing from the scope of the present invention, the piston pin 4 may be supported with a slight play in the piston 1.

[0030] The first outside diameter 10, the second outside diameter 11, the diameter B of the first center bore 2 and the diameter A of the second center bore 3 are of different sizes, the diameter B of the first center bore 2 being formed to complement the first outside diameter 10 and the diameter A of the second center bore 3 to complement the second outside diameter 11. This prevents an incorrect fitting of the piston pin 4, since it is possible to fit the piston pin 4 into the piston 1 in only one direction, in such a way that the first cylindrical longitudinal end area 8 is arranged in the first center bore 2 complementing the first outside diameter 10 and the second cylindrical longitudinal end area 9 is arranged in the second center bore 3 complementing the second outside diameter 11.