EP2505838B1 - Piston compressor - Google Patents

Description

The invention relates to a reciprocating compressor.

It is common practice to drive reciprocating compressors via a crank mechanism. In this case, the movement coupling of a piston of the reciprocating compressor with a crankshaft takes place via a connecting rod mounted on a crankpin of the crankshaft. The connecting rod bearing is usually designed as an oil-lubricated slide bearing.

In dry-running reciprocating compressors, the use of such oil-lubricated plain bearings is not possible. Here instead rolling bearings must be used as a rod bearing. In order to mount these, the crankshaft can be made in several parts, i. be designed as a so-called built crankshaft. After mounting the bearings, the individual parts of the crankshaft are assembled into the complete crankshaft. In this context, it is known to press the parts of the crankshaft together, but this has the disadvantage that it is then no longer easily possible to disassemble the crankshaft again, e.g. if necessary, replace a bearing mounted on a plug. Furthermore, it is known to form-fit the parts of a multi-part crankshaft by means of a Hirth toothing. In this case, it is possible to easily separate the parts of the crankshaft from each other again, z. B. to replace a mounted on the Hupzapfen defective rolling bearing against a new one. However, the disadvantage is the relatively large production cost and the associated relatively high costs in the production of a Hirth toothing.

Out CH 93365 A a crankshaft is known, is connected to a crank pin with a crank arm characterized in that a tapered in the direction of the crank arm portion of the pin engages in a formed on an end portion of the crank arm recess which tapers corresponding to the taper of the end portion of the crank pin, wherein the crank pin is clamped by means of a screw connection between crank pin and crank arm. In order to prevent a rotation of the crank arm relative to the journal, the end section of the crank pin and the recess on the crank arm have a non-circular cross-section.

In FR 610 596 A is a built-crankshaft described, are connected to the crank pin and a crank arm by means of a conical connection. In order to prevent a rotational movement of the crank arm relative to the crank pin, a pin lock is provided, wherein a locking pin engages in a bore formed on the crankshaft, which is arranged such that it has a recess for receiving an end portion of the crank pin and in the recess located tangent tangent end portion of the crank pin.

Against this background, the invention has for its object to provide a reciprocating compressor with a multi-part crankshaft whose parts can be releasably connected to each other in a simple and cost-effective manner.

This object is achieved by a reciprocating compressor having the features specified in claim 1. Advantageous developments of this piston compressor will become apparent from the dependent claims, the following description and the drawings. In this case, according to the invention, the features specified in the dependent claims in each case, but also in a technically meaningful combination, the inventive solution according to claim 1 further. The reciprocating compressor according to the invention has at least one piston that is moved by a crankshaft. The crankshaft is formed at least in two parts. In this case, such a division of the crankshaft is expediently provided, wherein at least a first part of the crankshaft in the unassembled state of the crankshaft forms a free end of a crank pin of the crankshaft, while on the second part of the crankshaft an angrerizende crank pin crank web is formed. All parts of the crankshaft may be formed, for example, as cast or forged parts. The free end of the first part of the crankshaft makes it possible to arrange a rolling bearing on the crankpin before assembling the crankshaft.

According to the invention, the at least two parts of the crankshaft are connected to each other by means of a conical connection. Accordingly, manufacturing technology simply the end of one of the parts to be joined together conical or frustoconical design and the other part correspondingly provided with a hollow cone-shaped recess. To connect the two parts, the first part is simply inserted with the conical end in the hollow cone-shaped recess of the second part and the two parts then clamped together, with the two parts center in the axial direction itself and only one component to the other component in terms the required angular orientation of the two adjoining the Hupzapfen crank webs must be aligned. The inventive design of the crankshaft not only allows a quick and easy initial assembly of the crankshaft but also later disassembly for maintenance or repair purposes.

According to the invention it is provided that a crank pin and a crank arm of the crankshaft are connected by means of the conical connection. As a result, one end of a first part of the crankshaft is formed by a crank pin, while a crank arm forms one end of a second part of the crankshaft. To form a conical connection between the first and the second part of the crankshaft or between the crank pin and the crank arm, the free end of the crank pin preferably tapers conically, while on the crank arm, which forms an end of the second part of the crankshaft, a conical outside Recess is formed, which extends transversely to the longitudinal extent of the crank arm.

Particularly favorable, the first and the second part of the crankshaft can be screwed together. Thus, it is advantageously provided that the conical connection forming areas of crank pin and crank arm are braced by means of a screw. This screw is expediently arranged and aligned in such a way that it pulls the conical end of the crank pin into the design formed on the crank cheek during a screwing movement for bracing the conical connection.

In a tensioned by screw conical connection between crank pin and crank arm an embodiment is preferred in which the screw engages through the crank arm in the axial direction of the crank pin and engages in an end portion of the crank pin. That is, in the crank pin, a threaded blind hole is preferably formed, while in the crank arm, a through hole is formed, which extends completely through the crank arm in the axial direction of the crank pin and transverse to the longitudinal extent of the crank arm. As soon as the conical end of the crank pin engages in the conical recess formed on the crank web, the through hole formed on the crank web and the threaded blind hole formed on the crank pin are in alignment, so that a screw guided through the through bore of the crank web can now be screwed into the threaded blind hole of the crank pin , Where a head of the screw coming to rest on the crank arm presses the crank arm against the crank pin and braces the crank arm with the crank pin. The through-hole preferably has a larger diameter than the screw, so that it has play in the through hole and centering takes place via the conical connection.

In a further development of this embodiment, the screw preferably engages centrally in the crank pin. Accordingly, a center axis of the crank pin and a center axis of the threaded bolt hole formed on the crankpin coincide. The screw forms an axis of rotation about which the second part of the crankshaft with the crank arm can be rotated relative to the first part of the crankshaft with the crank pin and vice versa for the exact alignment of the first part relative to the second part with not yet completely screwed screw. Once the two parts of the crankshaft have the required orientation, the screw can be completely screwed, ie firmly clamped the end of the crank pin in the crank arm become. In this case, a first fixation of the angular position is achieved by the frictional engagement in the conical connection. Instead of a central arrangement of the screw and a decentralized arrangement in the crank pin is possible.

After this alignment of the second part of the crankshaft has taken place relative to the first part of the crankshaft, the position of the second part of the crankshaft with respect to the first part of the crankshaft typically should not change any more. For this purpose, the connection of crank arm and crank pin is secured by means of an additional rotation. The rotation lock is expediently formed by positive locking elements, which engage at the same time in the crank arm and the crank pin substantially, transversely to a possible direction of rotation of the second part of the crankshaft relative to the first part.

The invention provides that at least one locking pin penetrating the crank arm and engaging in the crank pin forms the security against rotation. Here, a bore is formed on the crank web and formed on the crank pin a blind hole, wherein the blind hole on the crank pin with proper alignment of the first part of the crankshaft relative to the second part in direct extension to the bore on the crank arm, i. Is arranged coaxially with the bore of the crank arm.

It is further provided that the at least one locking pin radially spaced from the screw axially parallel to the crank pin engages through the crank arm and engages in the crank pin. Accordingly, the locking pin is guided in a bore extending from the side facing away from the crankpin side of the crank arm laterally next to the screw for bracing the two parts of the crankshaft and parallel to a longitudinal axis of this screw and extending parallel to the central axis of the crank pin through the crank arm and into the crank pin adjacent thereto. By the locking pin is arranged axially parallel to the crank pin, it is also arranged axially parallel to a rotational axis of the crankshaft. This is advantageous in that the locking pin is aligned transversely to the moments to be transmitted.

In order to reduce the torque load acting on the locking pin during operation of the crankshaft, two locking pins are preferably provided. These two locking pins are advantageously aligned axially parallel to the crank pin and preferably arranged such that they engage in the crank pin diametrically opposite one another. Thus, the leading through the crank arm in the crank pin holes for receiving the locking pins both extend in a plane in which the central axis of the crank pin lies, wherein the two locking pins are arranged on two opposite sides of the central axis of the crank pin and preferably each one same Distance from the central axis of the journal.

In terms of manufacturing technology, the bore for receiving the at least one securing pin is preferably made after the assembly of the conical connection, i. formed after the alignment of the two parts of the crankshaft and their tension with each other. Thus, the bore in the crank arm and the blind hole in the crank pin can be formed simultaneously aligned with each other. The bore or holes for receiving the locking pin or the locking pins are thus prepared when the two parts of the crankshaft have their final position to each other. Advantageously, they can then each be made quickly and easily in one drilling operation.

According to a further advantageous embodiment, adjusting surfaces are to each of the parts to be interconnected with the crankshaft relative alignment of these parts formed to each other. These adjusting surfaces are each flat surfaces on an outer side of these parts of the crankshaft, which are arranged so that the parts of the crankshaft to be joined together, when the Justierflächen rest on a flat reference surface, exactly the required orientation to each other.

Fig. 1

in perspektivischer Darstellung einen Kolbenverdichter und

Fig. 2

in perspektivischer, teilgeschnittener Darstellung eine Kurbelwelle des Kolbenverdichters nach Fig. 1.

The invention is explained in more detail with reference to an embodiment shown in the drawings. In the drawings shows

Fig. 1

in perspective view of a reciprocating compressor and

Fig. 2

in perspective, partially sectioned view of a crankshaft of the reciprocating compressor after Fig. 1 ,

At the in Fig. 1 The reciprocating compressor is a two-stage, dry-running reciprocating compressor with two cylinders 3 and 5. To drive the piston arranged in these cylinders 3 and 5, the latter are each connected via an unillustrated connecting rod with the In Fig. 2 shown crankshaft motion coupled.

The outer ends of these are formed by shaft journals 2 and 4, which define an axis of rotation A of the crankshaft. Between the shaft journals 2 and 4, the crankshaft has two cranks 6 and 8. The first crank 6 of the crankshaft directly adjoining the shaft journal 2 is formed by two crank webs 10 and 12 projecting radially outwards with respect to the shaft journals 2 and 4, which are connected via a crank pin 14 whose central axis B radially from the common center axis A of the shaft journal 2 and 4 is spaced apart, are interconnected. The second crank 8 is from the crank arm 12, a further parallel to the crank arm 12 aligned crank arm 16 and a crank webs 12 and 16 connecting crank pin 18 is formed. A central axis C of the crank pin 18 is radially spaced in the opposite direction to the central axis B of the crank pin 14 from the central axis A of the shaft journals 2 and 4.

The crankshaft is formed in three parts. Thus, the shaft journal 2 and the crank arm 10 form a first part of the crankshaft, the crank pin 14 with the crank arm 12 and the crank pin 18 a second part of the crankshaft and the crank arm 16 and the shaft journal 4, a third part of the crankshaft. The three parts of the crankshaft are each connected by means of conical connections. The three-part design of the crankshaft makes it possible to mount roller bearings on the crank pins 14 and 18.

To form a conical connection between the first and the second part of the crankshaft, an end portion 20 of the crank pin 14 tapers conically. Corresponding thereto, a recess 22 is formed on the crank arm 10 on the side remote from the shaft journal 2, which also tapers conically. The crank pin 14 engages with its end portion 20 in the formed on the crank arm 10 recess 22 a. In this position, the crank pin 14 is clamped to the crank arm 10 with a screw 24.

Starting from the side facing the shaft journal 2, this screw 24 extends through the crank web 10 and engages in the crank pin 14 at the front side. For this purpose, a bore 26 is formed on the crank web 10, which extends transversely to the longitudinal extent of the crank arm 10 through the crank web 10 therethrough. At the crank pin 14 extends from the end face a threaded blind hole 28 in the direction of the central axis B of the crank pin 14. A shaft 2 facing the end portion 29 of the bore 26 is formed radially widened and serves to receive a screw head of the screw 24 designed as a hexagon socket screw.

In order to ensure that the first part of the crankshaft has the required alignment with the second part of the crankshaft, alignment surfaces 30 and 32 are formed on the crank webs 10 and 12, respectively, on an outer side aligned substantially transversely to the central axis B of the crank pin 14. With proper alignment of the first and second parts of the crankshaft, the alignment surfaces 30 and 32 lie flat on a flat, not shown, reference surface.

The connection of the crank pin 14 with the crank arm 10 is secured by means of a rotation. The anti-rotation is formed by two locking pins 34 and 36, which is arranged in each case in a crank arm 10 by breaking and engaging in the crank pin 14 bore. Thus, the locking pin 34 is disposed in a bore 38 and the locking pin 36 in a bore 40. The central axes of the holes 38 and 40 are in a common plane with the central axis B of the crank pin 14, wherein the holes 38 and 40 on opposite sides of the screw 24 and radially spaced from the screw 24 are arranged diametrically opposite one another. In a particularly simple manner, the bores 38 and 40 are formed for receiving the locking pins 34 and 36 in the assembled, shown in the drawing state of the crankshaft, ie when the second part of the crankshaft with the crank pin 14 with the first part of the crankshaft with the Crankshaft 10 are clamped together by means of the screw 24 and the first and the second part of the crankshaft have the required relative orientation to each other. As a result, the portions of the bores 38 and 40 provided in the crank web 10 and in the crank pin 14 can each be formed jointly in one drilling operation. The conical connection between the second and the third part of the crankshaft substantially corresponds to the conical connection between the first and the second part of the crankshaft. A side facing away from the crank arm 12 end portion 42 of the crank pin 18 tapers conically. Corresponding to the conical end portion 42 of the crank pin 18, a hollow cone-shaped recess 44 is formed on the crank arm 16 on the side remote from the shaft journal 4, in which engages the conical end portion 42 of the crank pin 18.

By means of a screw 46 which, like the screw 24, is designed as a hexagon socket screw, the second part of the crankshaft is clamped to the third part of the crankshaft. To receive the screw 46, a bore 48 is formed on the crank web 16 and a threaded blind hole 50 is formed on the crank pin 18 on the face side. A common center axis of bore 48 and threaded blind hole 50 coincides with the central axis C of the crank pin 18. For receiving a screw head of the screw 46, an end portion 52 of the bore 48 facing away from the crank pin 18 is radially widened.

The connection of the crank pin 18 with the crank arm 16 is secured by means of a rotation in the form of locking pins 54 and 56 against unwanted rotational movement of the two parts relative to each other. The locking pin 54 is in a bore 58 and the locking pin 56 is disposed in a bore 60. The holes 58 and 60 are arranged at a radial distance on opposite sides of the screw 46 diametrically opposite one another. The center axes of the holes 58 and 60 lie in a common plane with the central axis C of the crank pin 18. Also, the holes 58 and 60 are suitably formed in the assembled state of the crankshaft, namely, when the third part of the crankshaft is connected to the second part ,

LIST OF REFERENCE NUMBERS

2 -

shaft journal

4 -

shaft journal

6 -

cranking

8th -

cranking

10 -

crank web

12 -

crank web

14 -

crank pins

16 -

crank web

18 -

crank pins

20 -

end

22 -

recess

24 -

screw

26 -

drilling

28 -

Threaded blind hole

30 -

adjustment surface

32 -

adjustment surface

34 -

safety pin

36 -

safety pin

38 -

drilling

40 -

drilling

42 -

end

44 -

recess

46 -

screw

48 -

drilling

50 -

Threaded blind hole

52 -

end

54 -

safety pin

56 -

safety pin

58 -

drilling

60 -

drilling

A -

Rotary axis, central axis

B -

central axis

C -

central axis

Claims (5)

1. A piston compressor with at least one piston which is coupled in movement to a crankshaft, said crankshaft being designed in an at least two-part manner and comprising a crank pin (14, 18) and a crank web (10, 16) which are connected by way of a cone connection, wherein the regions of the crank pin (14, 18) and of the crank web (10, 16) which form the cone connection are clamped by way of a screw (24, 26) which engages through the crank web (10, 16) in the axial direction of the crank pin (14, 18) and engages into an end-section (20, 42) of the crank pin (14, 18) and wherein the connection of the crank web (10, 16) and the crank pin (14, 18) is secured by way of a rotation lock formed by at least one securing pin (34, 36, 54, 56) which engages through the crank web (10, 16) and engages into the crank pin (14, 18), characterised in that the securing pin (34, 36, 54, 56) engages through the crank web (10, 16) in a manner radially distanced to the screw (24, 46) and axially parallel to the crank pin (14, 18), and engages into the crank pin (14, 18).
2. A piston compressor according to claim 1, characterised in that the screw (24, 46) engages centrally into the crank pin (14, 18).
3. A piston compressor according to one of the preceding claims, characterised in that two securing pins (34, 36, 54, 56) are provided, which are arranged in a manner such that they engage into the crank pin (14, 18) in a manner lying diametrically opposite one another.
4. A piston compressor according to one of the preceding claims, characterised in that a bore (38, 40, 58, 60) is provided in the crank pin (14, 18) and the crank web (10, 16), for receiving the at least one securing pin (34, 36, 54, 56), said bore having been formed after the assembly of the cone connection.
5. A piston compressor according to one of the preceding claims, characterised in that adjustment surfaces (30, 32) are formed on each of the parts of the crankshaft which are to be connected to one another, for the relative alignment of these parts to one another.

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