DE102012216418A1 - unbalanced shaft - Google Patents

Abstract

A lightweight unbalanced shaft (1, 1 ') is proposed to compensate for inertial forces and / or moments of inertia of an internal combustion engine. The unbalanced shaft comprises a carrier shaft designed as a hollow profile (2, 2 ') and one or more unbalanced masses (3, 3') joined to the carrier shaft in the area of the hollow profile. The hollow profile should have a non-circular profile cross section, the hollow profile and the unbalanced masses being joined to one another at their outer circumference.

Description

The invention relates to an imbalance shaft to compensate for inertial forces and / or moments of inertia of an internal combustion engine, comprising an at least partially formed as a hollow profile carrier shaft and one or more in the region of the hollow profile with the carrier shaft joined imbalance masses.

Background of the invention

Built unbalanced shafts with a trained as a hollow shaft carrier shaft and attached imbalance masses are for example from the DE 100 24 768 A1 and the DE 103 20 747 A1 known. In both cases, the carrier shaft is hollow cylindrical and the circumference of which is enclosed by the imbalance masses mounted thereon.

A disadvantage of these known designs is the limited lightweight potential, i. the ability to reduce the shaft mass at given unbalance.

Object of the invention

The present invention has for its object to provide a built lightweight shaft of the type mentioned.

Summary of the invention

The solution to this problem arises from the features of claim 1, while advantageous developments and refinements of the invention are the dependent claims. Accordingly, the hollow profile should have a non-circular profile cross-section, wherein the hollow profile and the imbalance masses are joined to each other at their outer periphery.

Compared to the cited prior art, the high lightweight potential of the imbalance shaft according to the invention results from the fact that the carrier shaft is not completely enclosed by the imbalance mass or masses, so that the imbalance mass counteracting the imbalance of the imbalance is kept small on the shaft peripheral portion facing away from the imbalance direction. Starting from a known imbalance shaft, this leads to a shift of the overall center of gravity in the direction of the wave imbalance, so that a shaft according to the invention can be executed with unchanged imbalance with significantly lower mass and correspondingly lower weight.

The carrier shaft expediently has a center of gravity which extends beyond the longitudinal axis with respect to the imbalance direction of the imbalance shaft. In this center of gravity distribution of the wave components of the center of gravity of the imbalance masses of the shaft longitudinal axis in favor of the space occupied by the rotating shaft space (envelope of imbalance masses) are kept small, while the wave imbalance counteracting carrier wave component due to the small absolute mass due to the hollow profile is also small.

The hollow profile is particularly preferably produced by hydroforming, hereinafter referred to as IHU for short. The imbalance masses may be provided with undercuts, in which the hollow profile is formed to form the joint connection with the imbalance masses. As an alternative or in addition to this purely positive connection, it is also possible to provide a material connection, for example produced by a welded connection, between the carrier shaft and the imbalance masses.

The unbalanced shaft should also be mounted radially on one or more journal, wherein a first part of the circumference of the bearing pin is formed by the carrier shaft and a second part of the circumference of the bearing journal by the imbalance masses. The shape of the bearing pin is preferably carried out by means of the hydroforming process.

The journals are preferably formed fully cylindrical. Alternatively, however, also part-cylindrical bearing journals may be provided, the bearing race extending over a circumferential angle of less than 360 °, the raceway interruption facing away from the imbalance, i. load-free peripheral portion of the imbalance shaft runs.

In the case of a radial roller bearing of the imbalance shaft and a non-rolling material structure of the support shaft, the unbalanced shaft may comprise mounted on the bearing pin rolling bearing inner rings.

The imbalance masses should each extend over a circumferential angle of at most 180 ° and thus have no mass counteracting the imbalance in favor of the low shaft mass on the other side of the shaft longitudinal axis.

Brief description of the drawings

Further features of the invention will become apparent from the following description and from the drawings, in which embodiments of unbalanced shafts according to the invention are shown in simplified form. Unless otherwise stated, the same or functionally identical features or components are provided with the same reference numbers. Show it:

1 a first imbalance shaft in side view;

2 a second imbalance shaft in side view;

3 the cross-section II according to 1 in a first embodiment;

4 the cross-section II according to 1 in a second embodiment;

5 the cross section II according to 1 in a third embodiment;

6 the cross section II according to 1 in a fourth embodiment.

Detailed description of the drawings

In the 1 shown imbalance wave 1 serves to compensate for free mass forces of second order of an internal combustion engine in four-cylinder in-line construction. In this known as Lancaster compensation balancing two unbalanced shafts rotate with double crankshaft speed in opposite directions.

The imbalance wave 1 is made up of individual components, namely a carrier shaft 2 and two imbalance masses joined together 3 , The carrier shaft is formed substantially as a hollow profile, in the end a massive drive part 4 made of cast steel for receiving a thrust bearing and a drive wheel (not shown) is firmly inserted. The radial bearing of the imbalance shaft takes place on two journals 5 , which are formed here as an inner race for the needles of a needle sleeve (not shown). A first partial extent 6 Each journal is formed by the carrier shaft and extends with respect to the arrow through the 7 symbolized unbalance direction beyond the longitudinal axis 8th the imbalance wave. A second subset 9 Each trunnion is formed by the unbalanced mass consisting of the bearing steel 100Cr6 and complements the trunnion with a circumferential angle α of about 160 ° to a solid cylinder (see 3 ). Due to the unbalance point loading of the journals, the first part circumference 6 only slightly or not at all loaded by the needle bearing and can therefore with lower demands on the rolling resistance of the material structure and also significantly narrower than the opposite second part of the circumference 9 with the in imbalance direction 7 extending load zone be executed on the journal.

The hollow profile of the carrier shaft 2 is made by means of the known hydroforming process and has - from the joint with the drive part 4 apart - over its entire length a non-circular profile cross-section, which in the area of the journals 5 is substantially semicircular. It goes through the point 10 symbolized center of gravity of the carrier wave with respect to the unbalance direction 7 the imbalance wave 1 beyond its longitudinal axis 8th , The joint connection of the carrier shaft with the imbalance masses 3 runs in each case on the outer circumference of the hollow profile and the imbalance masses.

As in the 3 and 4 shown simplified, the joint connection can be made by positive engagement by the carrier shaft 2 during the hydroforming process in undercuts of the imbalance masses inserted in the hydroforming die 3 is formed. The undercuts are according to 3 through a footbridge 11 the imbalance mass with a recess extending therein 12 and according to 4 through a footbridge 13 formed the imbalance mass, which opposes the unbalance direction 7 (please refer 1 ) widened.

As in the 5 and 6 shown, the joint connection can also cohesively and here by welding 14 the carrier wave 2 with the imbalance masses 3 be prepared.

The in 5 illustrated journal 5 is in addition with an attached rolling bearing inner ring for increased rolling resistance 15 Mistake.

In the 2 shown imbalance wave 1' differs from the imbalance wave 1 according to 1 essentially only in that the carrier shaft 2 ' with only one continuous imbalance mass 3 ' is added.

LIST OF REFERENCE NUMBERS

1

 unbalanced shaft

2

 carrier wave

3

 unbalanced mass

4

 driving part

5

 pivot

6

 first partial circumference of the trunnion

7

 unbalance direction

8th

 Longitudinal axis of the imbalance shaft

9

 second partial circumference of the journal

10

 Mass center of the carrier wave

11

 web

12

 deepening

13

 web

14

 welding

15

 Bearing inner ring

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10024768 A1 [0002]
• DE 10320747 A1 [0002]

Claims (8)

Imbalance shaft ( 1 . 1' ) for compensating for mass forces and / or moments of inertia of an internal combustion engine, comprising a carrier shaft (at least in regions) designed as a hollow profile ( 2 . 2 ' ) and one or more in the region of the hollow profile with the carrier shaft ( 2 . 2 ' ) attached imbalance masses ( 3 . 3 ' ), characterized in that the hollow profile has a non-circular profile cross-section, wherein the hollow profile and the imbalance masses ( 3 . 3 ' ) are joined to each other at the outer periphery thereof. Imbalance shaft ( 1 . 1' ) according to claim 1, characterized in that the carrier shaft ( 2 . 2 ' ) a mass focus ( 10 ), which with respect to the unbalance direction ( 7 ) of the imbalance shaft ( 1 . 1' ) beyond its longitudinal axis ( 8th ) runs. Imbalance shaft ( 1 . 1' ) according to claim 1, characterized in that the hollow profile is made by hydroforming. Imbalance shaft ( 1 . 1' ) according to claim 3, characterized in that the imbalance masses ( 3 . 3 ' ) with undercuts ( 11 . 12 . 13 ) are provided, in which the hollow profile to form the joint connection with the imbalance masses ( 3 . 3 ' ) is formed. Imbalance shaft ( 1 . 1' ) according to claim 1, characterized by one or more bearing journals ( 5 ) for the radial bearing of the imbalance shaft ( 1 . 1' ), with a first subset ( 6 ) of the journals ( 5 ) through the carrier shaft ( 2 . 2 ' ) and a second subset ( 9 ) of the journals ( 5 ) by the imbalance masses ( 3 . 3 ' ) is formed. Imbalance shaft ( 1 . 1' ) according to claim 5, characterized in that the bearing journals ( 5 ) are fully cylindrical. Imbalance shaft ( 1 . 1' ) according to claim 5 or 6, characterized in that the imbalance shaft ( 1 . 1' ) on the bearing journal ( 5 ) fixed roller bearing inner rings ( 15 ). Imbalance shaft ( 1 . 1' ) according to claim 1, characterized in that the imbalance masses ( 3 . 3 ' ) each extend over a circumferential angle (α) of a maximum of 180 °.

Images