DE202018104581U1 - Balance shaft and balance shaft and bearing system - Google Patents

Abstract

Balancing shaft (1) for balancing mass forces and / or moments of inertia, in particular for balancing mass forces and / or moments of inertia of a reciprocating internal combustion engine, comprising: - an elongate base body (2); - at least one bearing area (10) formed on the base body (2) on the outer circumference of the balance shaft (1), via which the balancer shaft (1) can be mounted for rotation about an axis of rotation (R) by means of a bearing (50); and - at least a first imbalance section (11) whose center of gravity lies outside the axis of rotation (R) of the balancing shaft (1), the longitudinal direction of the bearing area (10) forming the reduced bearing surface of the bearing (50) on the bearing area (10). LR) of the base body (2) seen against an inner side (IS) of the bearing (50) arched and seen in the transverse direction (QR) first curvature (K1) of the storage area (10) smaller than a second curvature (K2) of the inside ( IS) of the bearing (50).

Description

The present invention relates to a balance shaft and a balance shaft and bearing system.

Balancing shafts are well known from the prior art, for example from the DE 10 2015 218 277 A1 , Such balance shafts are used to compensate for inertial forces and / or inertial moments, which are caused in an internal combustion engine by a crankshaft during its rotation. As a result, operating noise and vibrations of the internal combustion engine can be reduced. To compensate for the inertial forces, unbalance portions are specifically formed on an elongated base body, which provide compensating counter-forces to the forces emanating from the crankshaft during the rotation of the balance shaft. The balance shafts are driven, for example via gears or belts synchronously to the crankshaft. Depending on the design of the internal combustion engine one or two balance shafts are used or the balance shaft is driven at a speed or a double speed of the crankshaft.

Due to the in operation, d. H. During the rotation of the balancing shaft about a rotation axis, occurring forces, the balance shaft deforms or bends. This bending typically leads to a tilting of a bearing area, via which the balance shaft is mounted in rotation about the axis of rotation by means of a bearing. As a result, the balancer shaft and the bearing are loaded unevenly in the bearing area and wear occurs.

It is thus an object of the present invention to provide a balance shaft with which a load and thus a wear for the balance shaft and the bearing parts can be reduced.

This object is achieved by a balance shaft according to claim 1, as well as a system according to claim 11. Further advantages and features of the invention will become apparent from the subclaims and the description and the accompanying figures.

• - einen länglichen Grundkörper;
• - zumindest einen am Grundkörper ausgebildeten Lagerbereich am äußeren Umfang der Ausgleichswelle, über den die Ausgleichswelle zur rotierenden Lagerung um eine Rotationsachse mittels eines Lagers lagerbar ist; und
• - zumindest einen ersten Unwuchtabschnitt, dessen Masseschwerpunkt außerhalb der Rotationsachse der Ausgleichswelle liegt; wobei zur Ausbildung eines reduzierten Auflagebereichs des Lagers am Lagerbereich
• - der Lagerbereich in Längsrichtung des Grundkörpers gesehen gegenüber der Innenseite des Lagers gewölbt und
• - eine in Querrichtung des Grundkörpers gesehen erste Krümmung des Lagerbereichs kleiner als eine zweite Krümmung einer Innenseite des Lagers ist.

According to the invention, a balancing shaft is provided for compensating mass forces and / or moments of inertia, in particular for balancing mass forces and / or mass moments of a reciprocating internal combustion engine, comprising:

• - an elongated body;
• - At least one formed on the base body bearing area on the outer circumference of the balancer shaft, via which the balancer shaft for rotating support about an axis of rotation by means of a bearing can be stored; and
• - At least a first unbalance portion whose center of gravity is outside the axis of rotation of the balance shaft; wherein to form a reduced contact area of the bearing in the storage area
• - The storage area seen in the longitudinal direction of the body arched over the inside of the bearing and
• - A viewed in the transverse direction of the base body first curvature of the storage area is smaller than a second curvature of an inner side of the bearing.

Compared to the prior art, in addition to the curvature in the longitudinal direction, the bearing area is specifically dimensioned such that the first curvature in the bearing area of the balancing shaft is smaller than a second curvature of the inside of the bearing. As a result, the bearing surface between bearing and bearing area is reduced in two directions or dimensions, so that in the theoretical ideal case, the bearing contacted only one support point the bearing area and cant tilt freely in two different directions without additional load, instead of only in the longitudinal direction, when the storage area would be arched or cambered only in the longitudinal direction.

Preferably, the transverse direction is perpendicular to the longitudinal direction of the balance shaft. A reduced contact area is preferably to be understood as meaning that the inside of the bearing does not make contact with the entire area of the bearing area when the bearing is mounted on the balancing shaft. The reduced bearing or support area can, for example, also take the form of a line, a strip or another two-dimensional shape. The curvature in the longitudinal direction is preferably assigned to a third curvature. In particular, it is provided that the balance shaft, in particular the bearing area, by the first curvature in addition to a crowning or crowning by the third curvature receives an additional crown in the transverse direction, in which it is already curved to support the bearing. As a result, a kind of ball support for the bearing can be realized.

The term "warehouse" in particular, all parts are to be understood, which are part of a warehouse, we z. B. an inner ring or a race. The second curvature is preferably determined by the inner diameter of the bearing or the inner ring or the raceway. In particular, the design of the storage area with the curvature and the first curvature allows a free tilting of the storage area relative to the Camp. A "free tilting" is preferably to be understood as meaning that the storage area can tilt without encountering load-bearing resistance or coming into contact with it. Preferably, the storage area has a width dimensioned in the longitudinal direction of 10 mm to 25 mm, preferably from 13 mm to 23 mm and particularly preferably from 16 to 19 mm.

Preferably, it is provided that the first curvature and / or the second curvature are dimensioned such that, taking into account manufacturing tolerances for the bearing area and the bearing, the first curvature is smaller than the second curvature. As a result, it can be advantageously ensured that the first curvature is always smaller than the second curvature, regardless of the respective error tolerances. In particular, it is provided that not only the size of the curvature or the inner diameter of the bearing is considered in the determination of the first curvature, but also the manufacturing tolerances when forging the balance shaft or making the bearing. For example, a first curvature averaged over a plurality of different balance shafts is smaller than a second curvature averaged over a plurality of different balance shafts, the value being greater than a sum, preferably greater than a double sum or more preferably greater than a threefold sum. from the error tolerances for the first curvature and the second curvature. For example, an inner diameter defining the second curve for the bearing within the manufacturing tolerances may assume a value between 9.5 and 10.5 mm. It is then preferably provided that the balancing shaft or the bearing area is dimensioned such that, within the expected tolerance limits, a diameter associated with the first curvature assumes a value between 8.5 and 9.5. In other words, it is preferably provided that the smallest value for the second curvature within the scope of the manufacturing tolerances is smaller than the largest value for the first curvature within the scope of the manufacturing tolerances.

For example, a manufacturing tolerance for the first curvature is between 5 to 20 .mu.m, while the manufacturing tolerance for the second curvature can be up to 5 .mu.m. Preferably, grinding can reduce the manufacturing tolerance of the first curvature to a value of up to a maximum of 5 μm.

In a further embodiment of the present invention, it is provided that a ratio between a first radius of curvature associated with the first curvature and a second radius of curvature associated with the second curvature has a value between 0.8 and 0.98, preferably between 0.9 and 0, 98 and more preferably between 0.95 and 0.98.

It is preferably provided that the storage area is post-processed for setting the first curvature, preferably coated or ground. As a result, the desired first curvature can be adjusted in an advantageous manner, in particular with a desired manufacturing tolerance. For example, the post-processing is done by a non-cutting or machining of the forged storage area. In particular, the storage area is ground during post-processing. A coating can additionally protect the positional area. For example, the bearing area is provided with a corresponding coating for protection against corrosion. It is also conceivable, for example, an elastic deformable coating that allows free tilting of the bearing.

It is expediently provided that the first radius of curvature varies in the direction of rotation. As a result, the shape of the storage area can be further optimized to support the free tilting of the bearing. The different first radii of curvature are preferably distributed uniformly or symmetrically along the direction of rotation. Preferably, the first radius of curvature along the direction of rotation does not deviate more than 10% from a maximum first radius of curvature. It is also conceivable that the first curvature is at least partially parabolic and / or elliptical.

Furthermore, it is conceivable that a largest first radius of curvature is smaller than the second radius of curvature. In other words, the second radius of curvature is always larger than the first radius of curvature at each position of the running area seen in the direction of rotation. As a result, it can be ensured with advantage that the bearing and the bearing area can tilt freely anywhere in the direction of rotation.

It is expediently provided that the bearing area has a strut element which extends in the longitudinal direction, wherein the largest first radius of curvature is realized on the side opposite the strut element. The largest first radius of curvature on the same side is the first unbalance section. In other words, the first radius of curvature is formed in the direction of rotation in the section of the bearing area which is subjected to the greatest load during operation.

In a further embodiment of the present invention, it is provided that the first curvature and / or a third curvature is elliptical.

• - der weitere Lagerbereich in Längsrichtung gesehen gewölbt und
• - ein in Querrichtung gesehen bzw. bemessene weitere erste Krümmung des weiteren Lagerbereichs kleiner als eine weitere zweite Krümmung einer Innenseite des weiteren Lagers ist.

Preferably, it is provided that the balance shaft has a further storage area over which the balance shaft for rotating support about an axis of rotation by means of another bearing can be stored, wherein to form a reduced bearing surface of the other bearing in the further storage area

• - The further storage area seen in the longitudinal direction arched and
• a further first curvature, seen in the transverse direction or dimensioned, of the further bearing region is smaller than a further, second curvature of an inner side of the further bearing.

In particular, it is provided that the first curvature differs from the further first curvature. By way of example, the first curvature is assigned the first curvature radius and the further first curvature is a further first curvature radius, the first curvature radius being different from the further first curvature radius, in particular if the second curvature and the further second curvature correspond to one another. As a result, it can be advantageously taken into account that the storage area and the further storage area can tilt to different degrees. For example, a degree of potential tilt depends on which end a power transmission is to drive the balance shaft.

It is preferably provided that the curvature has a third radius of curvature in the longitudinal direction of the bearing area and that the curvature of the bearing area has a further third radius of curvature seen in the longitudinal direction. In this case, the third radius of curvature preferably differs from the first radius of curvature in order to take account in each case of a different tilting of the balancing shaft in the bearing area and the further bearing area. For example, the third radius of curvature is 9000 mm, d. H. the contour of the storage area is only slightly curved in the longitudinal direction.

Another object of the present invention is a system of a balance shaft according to the invention and a bearing. All features described for the balance shaft according to the invention and their advantages can be analogously also transferred to the system according to the invention and vice versa.

Further advantages and features will become apparent from the following description of preferred embodiments of the subject invention with reference to the accompanying figures. Individual features of the individual embodiments can be combined with each other within the scope of the invention.

• 1: schematische Darstellung einer Ausgleichswelle gemäß einer beispielhaften Ausführungsform der vorliegende Erfindung und
• 2: Darstellung der Ausgleichswelle aus 1 im Betrieb und
• 3a und 3b Schnittansichten durch den Lagerbereich in Längsrichtung (3b) und Querrichtung (3a) gesehen.

It shows:

• 1 FIG. 2 is a schematic representation of a balance shaft according to an exemplary embodiment of the present invention and FIG
• 2 : Representation of the balance shaft 1 in operation and
• 3a and 3b Section views seen through the storage area in the longitudinal direction (3b) and transverse direction (3a).

In 1 is schematically a balance shaft 1 according to an exemplary embodiment of the present invention. Such balance shafts 1 are used in particular to compensate for inertial forces and / or moments of inertia, in particular to compensate for inertial forces and / or mass moments of a reciprocating internal combustion engine, to reduce operating noise and vibration and thus to increase ride comfort. These are targeted unbalance sections 11 . 12 . 21 and 22 at the balance shaft 1 designed, preferably forged, the mass forces or mass moments generate, which counteract those of a crankshaft of the internal combustion engine.

In the example shown in FIG 1 includes the balance shaft 1 an elongated body 2 at which a first imbalance section 11 and a second imbalance section 21 , are formed. Between the first unbalance section 11 and the second imbalance section 12 is a storage area 10 intended. The storage area 10 is provided as a contact area over which the balance shaft 1 by means of a warehouse 50 (in 1 and 2 not shown), for example a radial bearing, such as a needle bearing, is rotatable about an axis of rotation storable. For example, the storage area becomes 10 seen in the axial direction by a first collar element 16 and a second collar element 17 limited to prevent axial displacement of the bearings. Furthermore, a third imbalance section 21 and a fourth unbalance section 22 provided between which another storage area 20 is arranged.

The further storage area 20 becomes longitudinal LR or axial direction of the balance shaft 1 through a third collar element 26 and a fourth collar element 27 limited to avoid axial displacement of the other bearing. Compared to the storage area 10 is the further storage area 20 designed in the illustrated embodiment such that a width B a tread L the further storage area 20 seen in the direction of rotation U varies, in particular in a load section of the other storage area 20 is wider than a less stressed section of the further storage area 20 , Preferably, the width of the tread tapers continuously and / or discontinuously in the direction of rotation U seen. It would also be conceivable that the storage area 10 and the further storage area 20 each have running surfaces with a constant width or varying width.

In order to save material and thus weight, it is conceivable that the balance shaft in the storage area 10 and / or in the further storage area 20 is hollow, ie, a hollow area 30 having. Alternatively, it is also conceivable that a web element 15 or rib element in the longitudinal direction LR the balance shaft extends.

The balance shafts 1 for example, by gears 31 , Chains or timing belt synchronously driven by the crankshaft. In the illustrated embodiment is on the other storage area 20 facing the end of a power transmission area 40 provided on the example, a gear 31 is mounted or on which a belt is applied. For example, can a gear 31 on the the other storage area 20 Pull up facing end and frictionally and / or positively with the power transmission area 40 connect. Depending on the design of the internal combustion engine, one usually uses one or two balance shafts 1 that run at single or double crankshaft speed.

The 2 further shows the balance shaft 1 during operation, ie in a state in which the balance shaft 1 about the rotation thing R rotates. For example, the balance shaft 1 rotated at 5400 or more revolutions per minute. As a result of this rotation occur through the forces occurring during rotation bending in the balance shaft 1 on that in the 1 are greatly exaggerated for better understanding. According to this tilting the storage area 10 and / or the further storage area 20 tilted relative to the bearings, so that an uneven load or support between the bearing or the other bearing and the balance shaft 1 is caused. The different shades of gray show different local loads. To counteract a wear caused thereby and so to increase the life of the system of balance shaft and bearing, it is envisaged that the storage area 10 longitudinal LR is arched or cambered, so that the load on the bearing is reduced by the tilted storage area. In particular, it is according to 3 provided that in addition one in the transverse direction QR measured first curvature K1 of the storage area 10 smaller than a second curvature K2 an inside IS of the camp 50 is. This can be realized in an ideal manner in the ideal case, a punk-shaped support surface or ball support and on the camp 50 acting and tilted storage area 10 Outgoing loads can be advantageously reduced.

In the 3a is the storage area 10 in a sectional view along the transverse direction QR and in the 3b in a sectional view along the longitudinal direction LR the balance shaft 1 shown. In the 3b is also a warehouse 50 located. For example, it is in the illustrated part of the camp 50 around an inner ring of a rolling or ball bearing. For purposes of illustration, the contours of the storage area 10 ie a curvature or third curvature K3 along the longitudinal direction and the difference between the first curvature K1 and the second curvature K2 exaggerated. Preferably, one of the third curvature K3 associated third radius of curvature has a value of 9000 mm.

Furthermore, the first curvature can be K1 of the storage area 10 assign a first radius of curvature and the second curvature K2 a second radius of curvature. It is conceivable that the first radius of curvature varies seen in the circumferential direction U, while the second radius of curvature K2 remains constant.

LIST OF REFERENCE NUMBERS

1

balancer shaft

2

body

10

storage area

11

first unbalance section

12

second unbalance section

16

first collar element

17

second collar element

15

web element

20

additional storage area

21

third imbalance section

22

fourth unbalance section

26

third collar element

27

fourth collar element

30

hollow area

31

gear

40

Power transmission area

50

camp

L

tread

LR

longitudinal direction

QR

transversely

R

axis of rotation

B

width

IS

inside

K1

first curvature

K2

second curvature

K3

third curvature

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 102015218277 A1 [0002]

Claims (11)

Balancing shaft (1) for balancing mass forces and / or moments of inertia, in particular for balancing mass forces and / or mass moments of a reciprocating internal combustion engine, comprising: - An elongated body (2); - At least one on the base body (2) formed bearing region (10) on the outer periphery of the balance shaft (1) through which the balance shaft (1) for rotating support about a rotation axis (R) by means of a bearing (50) can be stored; and - At least a first unbalance portion (11) whose center of gravity is outside the axis of rotation (R) of the balancing shaft (1); wherein for forming the reduced bearing surface of the bearing (50) at the bearing area (10) - The bearing area (10) in the longitudinal direction (LR) of the base body (2) seen against an inner side (IS) of the bearing (50) arched and - A seen in the transverse direction (QR) first curvature (K1) of the storage area (10) is smaller than a second curvature (K2) of the inside (IS) of the bearing (50). Balance shaft (1) according to Claim 1 wherein the first curvature (K1) and / or the second curvature (K2) are dimensioned such that, taking into account manufacturing tolerances for the bearing area (10) and the bearing (50), the first curvature (K1) is smaller than the second curvature (K2). Balancing shaft (1) according to one of the preceding claims, wherein a ratio between a first curvature radius associated with the first curvature (K1) and a second curvature radius associated with the second curvature (K2) assumes a value between 0.8 and 0.98, preferably between 0 , 9 and 0.98, and more preferably between 0.95 and 0.98. Balance shaft (1) according to one of the preceding claims, wherein the bearing region (10) for adjusting the first curvature (K1) is post-processed, preferably coated and / or ground. Balancing shaft (1) according to one of the preceding claims, wherein the first radius of curvature varies in the direction of rotation (U). Balance shaft (1) according to Claim 5 wherein a largest first radius of curvature is smaller than the second radius of curvature. Balance shaft (1) according to Claim 6 in that the bearing area (10) has a strut element (15) which extends in the longitudinal direction (LR), the largest second radius of curvature being realized on the side opposite the strut element (15). Balancing shaft (1) according to one of the preceding claims, wherein the first curvature (K1) and / or a third curvature (K3) formed in the longitudinal direction (LR) at the bearing area for its curvature is elliptical. Balancing shaft (1) according to one of the preceding claims, wherein the balancing shaft (1) has a further bearing region (20), via which the balancing shaft can be mounted for rotation about an axis of rotation (R) by means of a further bearing, wherein to form a reduced Bearing surface of the further bearing at the further storage area (20) - The further storage area (20) viewed in the longitudinal direction arched and - A further first curvature of the further storage area (20) seen in the transverse direction (QR) is smaller than a further second curvature of an inner side of the further storage. Balance shaft (1) according to Claim 9 , wherein the first curvature (K1) differs from the further first curvature. Balancing shaft system (1) according to one of the preceding claims and a bearing (50).

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