Assembly comprising a pin and a crank and turbocharger having such an assembly

Abstract

The invention relates to an assembly (1, 2) comprising a pin (2) and a crank (1), in particular for a turbocharger, the crank (1) having a bore (12) in which a connecting portion (21) of the pin (2) for connecting the pin (2) with the crank (1) is fixed by an interference fit, wherein the bore (12) has a substantially circular cross-section and the connecting portion (21) has a circular cross-section, the cross-section of the bore (12) deviating from the circular shape at at least one location (121) and being larger than the cross-section of the connecting portion (22) at this location (121).

Description

TECHNICAL FIELD

[0001] The invention relates to an assembly comprising a pin and a crank, in particular for a turbocharger, the crank having a bore, a connecting portion of the pin for connecting the pin and the crank being press-fitted in the bore, the bore having a substantially circular cross-section and the connecting portion having a circular cross-section. BACKGROUND

[0002] From the document EP 2 663 754 B1 a turbocharger is known which has at least one air charge valve comprising an air flow regulating element, an actuator for regulating the air charge valve and an assembly of the above-mentioned type. The force generated by the actuator is transmitted to the air flow regulating element via the assembly of the crank and the pin. Between the crank and the pin there is a press-fit connection. For this purpose, the pin is pressed into the bore of the crank. The bore is slightly smaller in size relative to the region of the pin which is intended to be connected. The pin and the crank of this turbocharger are each made of steel.

[0003] Due to tolerances, the force required to insert the pin into the bore of the crank can be large. The greater the force required for the press-fit connection, the greater the risk of damaging the crank or the pin when establishing the connection. This risk exists in particular if the diameter of the bore is at the lower end of the tolerance interval for the diameter and the diameter is at the upper end of the tolerance interval for the diameter of the pin.

[0004] This is where the invention comes into play. SUMMARY

[0005] The invention is based on the problem of improving the assembly of the aforementioned type such that even in the case of an opposite tolerance deviation, a too great press-in force is not required to establish the connection between the pin and the crank.

[0006] According to the invention, this problem is solved by the fact that the cross-section of the bore deviates from the circular shape at at least one location and is larger at this location than the cross-section of the connecting region. This deviation of the cross-section of the bore from the cross-section of the connecting region of the pin (with opposite tolerance positions) can serve to reduce the press-fit force required to produce the press-fit connection between the pin and the crank. This can be explained by the fact that the pin deforms when being pressed into the bore such that material from the pin flows into the region of the cross-section of the bore which lies outside the circular shape of the remaining portion of the cross-section of the bore. A supplementary or alternative explanation is that the at least one point in the cross-section of the bore which lies outside the circular shape of the remaining portion of the cross-section makes it possible to widen the bore in the crank. Each of these effects and possibly other effects, alone or in combination, can lead to a reduction in the press-in force to be achieved.

[0007] In the assembly according to the invention, the cross-section of the hole can deviate from the circular shape at at least two opposite points and be larger than the cross-section of the connecting area at these points. Thus, the occurrence of the effect can be simplified and its effect enhanced.

[0008] The at least one deviation of the hole from the circular shape can be formed by a recess in the material of the crank around the hole in the crank.

[0009] The crank can be designed such that, apart from at least one location at which the cross-section of the hole deviates from the circular shape, the wall of the crank delimiting the hole in the crank follows a circular line. The wall of the pin delimiting the hole must be free of corners and edges. The change in direction of the wall of the pin delimiting the hole can be free of edges and corners.

[0010] The turbocharger according to the invention comprises at least one air charge valve having a gas flow regulating element, an actuator for regulating the air charge valve and an assembly according to the invention, the actuator and the regulating element being connected to one another via the assembly, such that the actuator can drive the regulating element via the assembly to regulate the air charge valve or the gas flow by the actuator. The actuator can have an output shaft, which is connected to the crank of the assembly of the invention and by which the crank can be driven. The pin of the assembly of the invention can be connected to a lever or a link and the lever or the link can be driven by the pin. The lever or the link can be connected to the gas flow regulating element to drive the element. BRIEF DESCRIPTION OF DRAWINGS

[0011] The invention is explained further below on the basis of the drawings. Thus in the drawings:

[0012] Figure 1 A perspective view of the pin and the crank before assembly to form the assembly according to the invention is shown,

[0013] Figure 2 A perspective view of the assembly of the journal and the crank is shown,

[0014] Figure 3 A view of a portion of the bottom of the crank is shown; and

[0015] Figure 4 A perspective view of the actuator and its assembly is shown. DETAILED DESCRIPTION

[0016] The crank 1 of the shown assembly 1, 2 is formed from a flat metal piece in which two holes 11, 12 are provided. The first hole 11 is used to fix the crank 1 to the output shaft 31 of the actuator 3. The fixing to the shaft 31 can be realized in different known ways. The second hole 12 is used to connect the crank 1 and the pin 2. The pin 2 has a first connection area 21 which is circular in cross section and is used to connect the pin 2 with the crank 1. The pin 2 also has a second connection area 22 which is circular in cross section and is used to connect the pin 2 to a mechanism by which elements for adjusting the air inflation valve can be connected to the assembly. The mechanism can have a lever or a link which is connected to the second connection area 22. Between the first connection area 21 of the pin 2 and the second connection area 22 of the pin 2, the pin 2 has a collar 20.

[0017] The second hole 12 has a region 120 which is circular in cross section. Following this region 120 are two opposite recesses 121. Due to these recesses 121, the cross section of the entire second hole 12 deviates from the circular shape. The cross section of the entire second hole 12 is larger than the region 120 which has a circular cross section.

[0018] The diameter of the cross section of the first connection area 21 of the pin 2 which is inserted into the second hole 12 is slightly larger than the diameter of the region 120 of the second hole 12 which has a circular cross section. If the second hole 12 did not have the recesses 121 beyond the circular section 120 and if the first connection area 21 of the pin 2 was inserted into the second hole 12 which then is circular in cross section, there would be an interference fit caused by the second hole 12 being too small or the first connection area 21 being too large. Depending on the position of the dimensions in the tolerance interval, this can result in a large force being required to press the first connection area 21 of the pin 2 into the second hole 12. By the recesses 121 by which the second hole 12 deviates from the circular shape and extends beyond the circular region 120 of the second hole 12 and also beyond the circular cross section of the first connection area 21, the force required to press the first connection area 21 into the second hole 12 can be reduced.

[0019] List of reference signs

[0020] 1 crank rocker

[0021] 11 first hole

[0022] 12 second hole

[0023] 120 circular region of the second hole

[0024] 121 recess

[0025] 2 pin

[0026] 20 collar

[0027] 21 first connection area

[0028] 22 second connection region

[0029] 3 actuator

[0030] 31 output shaft

Claims

1. An assembly (1, 2) comprising a pin (2) and a crank (1), the crank (1) having a bore (12), a connecting portion (21) of the pin (2) for connecting the pin (2) and the crank (1) being press-fitted in the bore, wherein, The hole (12) has a substantially circular cross-section and the connecting portion (21) has a circular cross-section, characterized in that the cross-section of the hole (12) deviates from the circular shape at at least one location and is larger than the cross-section of the connecting portion (21) at said location; the diameter of the cross-section of the connecting portion (21) of the pin (2) inserted into the hole (12) is larger than the diameter of the area (120) of the hole (12) having a circular cross-section.

2. The assembly (1, 2) according to claim 1, characterized in that The cross-section of the hole (12) deviates from the circular shape at at least two opposite locations and is larger than the cross-section of the connecting portion (21) at these locations.

3. Assembly (1, 2) according to claim 1 or 2, characterized in that The at least one deviation of the hole from the circular shape is formed by a recess (121) in the material of the crank (1) surrounding the hole (12) in the crank (1).

4. Assembly (1, 2) according to claim 1 or 2, characterized in that In addition to the at least one location at which the cross-section of the hole (12) deviates from the circular shape, the wall of the crank (1) defining the hole (12) in the crank (1) follows a circular line.

5. Assembly (1, 2) according to claim 4, characterized in that The wall of the crank (1) defining the hole (12) has no corners or edges.

6. The assembly (1, 2) according to claim 5, characterized in that The change in direction of the wall of the crank (1) defining the hole (12) has no edges and corners.

7. The assembly (1, 2) according to claim 1, characterized in that The assembly (1, 2) is used in a turbocharger.

8. A turbocharger comprising at least one air charge valve having a flow regulating element, an actuator (3) for regulating the air charge valve and an assembly (1, 2) according to any one of claims 1 to 7, wherein, The actuator (3) and the airflow regulating element are connected to each other via the assembly (1, 2) so that the actuator (3) can drive the airflow regulating element via the assembly (1, 2) to regulate the air charge valve or the airflow.

9. The turbocharger of claim 8 wherein, The actuator has an output shaft connected to the crank (1) of the assembly (1, 2) and the crank (1) can be driven by the output shaft.

10. The turbocharger of claim 9 wherein, The pin (2) of the assembly (1, 2) is connected to a lever or a link and the lever or the link can be driven by the pin (2).

11. The turbocharger of claim 10 wherein, The lever or the link is connected to the airflow regulating element of the air charge valve to drive the airflow regulating element of the air charge valve.

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