DE102012020674A1 - Method for connecting differential cage with driving wheel of axle differential gear box in passenger car, involves performing training process with rotating load, where amplitudes of load lie below rated load torque during process - Google Patents

Abstract

The method involves coating mating faces of a shaft component i.e. differential housing (200), and a hub component i.e. driving wheel (300), with a thin metal layer (410) before joining the faces to a shaft hub press connection (400). A training process is performed with an alternative rotating load after joining the mating faces to the press connection, where amplitudes of the rotating load lie below a rated load torque transmitted from the press connection during the training process. The shaft component is formed from a malleable cast iron material. An independent claim is also included for a structural unit for an axle differential gear box of a motor vehicle.

Description

The invention relates to a method for connecting a shaft component with a hub component by a shaft-hub press connection, for which at least one of the joining surfaces on the shaft component and / or on the hub component is coated with a thin metal layer before joining and with a training after joining an alternating rotation load is performed to increase the connection strength of the previously generated shaft-hub press connection.

The invention further relates to an assembly produced by such a method, which is in particular a structural unit for a passenger car axle differential. Joining a shaft component to a hub component by inducing a shaft-hub interference fit is common prior art. A shaft-hub press connection is understood to be a press-fit connection between the shaft component and the hub component, via which torques can be transmitted by frictional engagement.

In addition, it is known to provide the joining surfaces on the shaft component and / or on the hub component before joining with a thin metal layer, which forms a metallic intermediate layer (also referred to as solder layer) in the shaft-hub-press connection, the conditionally to a cohesive Connects, so that higher torque can be transmitted due to a higher connection strength (compared to a purely frictional connection). Such compounds are also referred to as press-press solder joints (PPLV).

Further, it is known that in press-press soldering joints, the connection strength and thus the torque transmission capability can be considerably increased by so-called exercising. For training, the already joined components are moved relative to each other (which is done by appropriate devices), which due to several effects, a significant increase in the connection strength of the respective shaft-hub-press connection is achieved.

The prior art is on the DE 10 2005 026 713 A1 the same applicant and, in addition, the DE 10 2008 035 438 A1 pointed.

The invention has for its object to provide a method of the type mentioned that the disadvantages associated with the prior art does not have or at least has a disadvantage only to a reduced extent.

This object is achieved by a method according to the invention with the features of claim 1. With the independent claims, the solution of the problem extends to building units according to the invention, which were prepared by the method according to the invention. Preferred developments and refinements emerge analogously for all subjects according to the invention both from the dependent claims and from the following explanations. Features of the method are thus equally structural features of the assembly of the invention and vice versa.

The inventive method for connecting a shaft component with a hub component by means of a shaft-hub press connection, for which at least one of the joining surfaces on the shaft component and / or the hub component before joining with a thin metal layer (or solder layer) is coated and after the joining is performed at least one training operation with an alternating (on the previously induced shaft-hub press-connection acting) rotational load to increase the connection strength of the generated or existing shaft-hub-press connection, characterized in that in this training process the Amplitudes of the alternating rotational load below and in particular well below a to be transmitted from the shaft-hub press connection nominal torque.

In other words, during the training process, the maximum torques applied to the previously produced shaft-hub press connection for the purpose of increasing strength are lower, and in particular significantly lower, than the maximum occurring later during normal operation of the interconnected components Nominal torque for which the components or components and the shaft-hub press connection are designed constructively.

In conventional training, the torques applied to the shaft-hub interference fit are typically well above the rated torque (where the rated torque may already be several thousand newton meters), which makes the components coupled together more stable (over target load) and thus more expensive and be designed to be heavier than required for operation under normal operating conditions.

Surprisingly, however, it has been shown that even with a training with lower torques, a significant increase in the connection strength of the respective shaft-hub-press connection is achieved (a significant increase in the connection strength can also be achieved if it during training to no discernible relative movement or Shifting between the components comes), bypassing the mentioned disadvantages. It is particularly advantageous that the components or components in terms of training need not be oversized constructively.

The inventive training a shaft-hub-press connection is made with an alternating rotational load, wherein the affected shaft-hub-press connection first in the first direction of rotation, then in the opposite second direction of rotation, then again in the first direction of rotation, and so on. This can be done with a corresponding device. Such an alternating rotational loading for the purpose of training can be carried out according to different time functions, for example according to a sine function, a trapezoidal function, a triangular function, a rectangular function and the like. These time functions can be symmetric or asymmetrical. An axial load of the shaft-hub-press connection for the purpose of training is preferably not provided. However, such an axial training of the affected shaft-hub-press connection, in particular in addition to the rotational load, may also be provided.

It is preferably provided that the amplitudes applied in the first direction of rotation and in the second direction of rotation are equal in magnitude. However, the amplitudes can also differ. Furthermore, it is possible to use time varying amplitudes. In the context of the invention, an amplitude is understood to mean, for the most part, a maximum value of the alternating and thus time-varying rotational load, in particular with respect to an average value of zero Newton meters (0 Nm). Incidentally, it is conceivable to superimpose the alternating rotational load of a static rotational load during training according to the invention.

It is preferably provided that the amplitudes of the alternating rotational load during training are less than 75%, preferably less than 50%, particularly preferably less than 45% and in particular less than 40% of the rated torque.

The alternating rotational load during training is ideally low frequency and is preferably less than 10 Hz and is in particular in the range between 2 Hz and 8 Hz.

Preferably, the wave component and the hub component, which are to be joined or joined with the method according to the invention, at least in the region of their joining surfaces, formed of different materials. Even in this case can be produced with the inventive method a very reliable and thus safe shaft-hub press connection between these components.

It is particularly preferably provided that the shaft component, at least in the region of its joining surface, is formed from a metal casting material, preferably from a cast iron material and in particular from a malleable cast iron (for example a GJMW material). Also in this case can be made with the inventive method a very reliable and thus safe shaft-hub press connection.

An assembly according to the invention comprises a shaft component (first component) and a hub component (second component) which are joined or connected to one another in a rotationally fixed manner by means of a shaft-hub press connection produced or produced by a method according to the invention.

In particular, it is provided that such a structural unit is a structural unit for an axle differential drive of a motor vehicle, in particular a passenger car, wherein this structural unit is a differential housing (first component or first component) and a drive wheel (second component or second component). and the differential housing forming the shaft component and the drive wheel forming the hub component are non-rotatably joined or connected to one another by means of a shaft-hub press connection produced or produced by a method according to the invention.

Accordingly, the invention also includes a method for producing such an assembly (or assembly) for an axle differential, comprising a differential housing (first component) and a drive wheel (second component) which are connected by means of a shaft-hub-press connection, for which at least one of the joining surfaces on the differential housing and / or on the drive wheel is coated with a thin metal layer prior to joining and after the joining a training operation with an alternating rotational load is performed to increase the connection strength of the generated shaft-hub-press connection, is provided in that during this training operation, the amplitudes of the alternating rotational loading are below the rated torque to be transmitted by the shaft-hub interference fit (between the differential housing and the drive wheel).

It is preferably provided that the drive wheel is arranged directly outside on the differential housing, for which purpose both the differential housing and the drive wheel have corresponding joining surfaces. The drive wheel is preferably designed as a ring gear.

The differential housing is preferably formed from a cast iron material and in particular from a malleable cast iron (for example a GJMW material). The drive wheel can, for. B. from a common case steel material (eg. 16MnCr5) may be formed. In such a combination of materials welding of the components for producing a rotationally fixed shaft-hub connection is not or only partially possible, the invention remedy this. Incidentally, the invention proposed producing a shaft-hub press connection compared to the welding offers significant advantages, such as. A smaller structural unit size and mass, a simpler joining process, lower equipment, material, manufacturing and energy costs, a substantial material independence the joining partner and the like more.

The shaft-hub press connection is preferably a so-called transverse press fit or a so-called transverse press connection. Alternatively, it may be a so-called longitudinal compression bandage. Cross press dressings and longitudinal press dressings and their production are known in the art. However, a shaft-hub press connection according to the invention has a metallic intermediate layer between the corresponding joining surfaces, which has to be considered in the production of the shaft-hub press connection. As a metallic coating or as a metallic intermediate layer, for example, zinc, copper, aluminum or nickel come into consideration.

The invention is explained in more detail below by way of example and not by way of limitation with reference to the schematic figures. However, the features shown in the figures and / or explained below may, regardless of specific feature combinations, be general features of the invention.

1 shows a sectional view of an inventive unit for an axle differential with a differential case and a drive wheel.

2 shows in a diagram the temporal torque curve when training the shaft-hub-press connection to the unit from 1 ,

1 shows a total with 100 Designated unit for a axle differential of a car. The construction unit 100 includes a differential case (or a differential cage) 200 and a drive wheel 300 , R denotes the common axis of rotation. Inside the differential case 200 is a pair of bevel gears 221 / 222 and a pair of axle bevel gears 231 / 232 arranged. The bevel gears 221 / 222 are on a common support bolt 210 held. The connected via splines with the Achswellenkegelrädern axle shafts or drive shafts are not shown. The drive wheel 300 is designed as a ring gear or bevel gear and has a wheel body 310 with a toothing formed thereon 320 on. In the differential case 200 it is a one-piece cast component manufactured from a malleable cast iron (eg GJMW). At the crown wheel 300 it is a one-piece forming and / or milling component manufactured from a case hardening steel (eg 16MnCr5).

The differential case 200 and the drive wheel 300 are via a shaft-hub press connection 400 rotatably connected to each other, so that during operation of the axle differential torque from the drive wheel 300 on the differential case 200 (and vice versa) are transferable. The drive wheel 300 is directly on the differential case 200 arranged, including the shaft component forming differential housing 200 and the hub component forming drive wheel 300 are formed with corresponding cylindrical joining surfaces. The shaft-hub press connection is provided with a metallic intermediate layer (solder layer) 410 formed, whereby between the corresponding joining surfaces on the differential housing 200 and at the drive wheel 300 also a conditional substance is given.

For making the shaft-hub press connection 400 Before joining, the joining surface on the differential housing 200 and / or on the drive wheel 300 coated with a thin metal layer. The following are the components 200 and 300 added, for what initially the drive wheel 300 heated and / or the differential case 200 is cooled and then the drive wheel 300 in the axial direction on the differential case 200 is pushed, as shown from right to left, the axial end position by a differential housing 200 trained ring shoulder 205 is predetermined. During the subsequent temperature compensation, a so-called transverse press connection sets in. The components 200 and 300 can also be joined in other ways.

Following and in particular directly after the joining of the components 200 and 300 is a training with a low-frequency alternating rotational load performed to increase the connection strength of the generated shaft-hub press connection 400 to increase. For this purpose, the drive wheel 300 held and over the differential case 200 (For example, by inserting rotary shafts in the Achswellenkegelräder 231 / 232 ) an alternating rotational load on the shaft-hub press connection 400 applied. Alternatively, the differential case 200 detained and the rotational load on the drive wheel 300 be applied. A combination of these two basic approaches is possible. The alternating rotational load during the training process is illustrated by the two arrows A and B arrows.

According to the invention, it is provided that the amplitudes of the alternating rotational load A / B are below that of the shaft-hub press connection 400 to be transmitted during operation nominal torque. This is in 2 illustrated by a diagram. The diagram shows the time torque curve m of the rotary load (m = F _(t) ) during training of the shaft-hub press connection 400 , The horizontal time axis is designated t, the vertical torque value axis is designated M (+ M / -M).

The maximum occurring during operation of the axle differential transmission torque, for both the components 200 and 300 as well as the shaft-hub-press connection 400 , especially taking into account the training process, is the _nominal torque denoted M _Nenn . This nominal torque M _nominal can be transmitted both in the first direction of rotation (A) and in the opposite direction of rotation (B). The training is carried out with a torque curve m whose amplitudes M * are both in one direction of rotation (A) and in the other direction of rotation (B) below the rated torque M _nom . In the diagram shown, the amplitudes M * of the torque curve m are approximately 70% to 75% of the nominal torque M _nominal (relative to M _nominal = 100%). During a load change (from A to B or vice versa), a rotary load with the value of NULL Newtonmeter (0 Nm) is briefly reached, namely when the torque curve m passes through the 0-axis.

The one with 2 illustrated torque curve m for the rotational load when training the shaft-hub-press connection 400 between the differential case 200 and the drive wheel 300 , as well as its amplitudes M * and the number of load changes, are only of a schematic nature and serve for explanation.

LIST OF REFERENCE NUMBERS

100

Assembly, assembly

200

differential case

205

annular shoulder

210

Bolts, spigots

221

pinion

222

pinion

231

side gear

232

side gear

300

drive gear

310

Wheel body, basic body

320

gearing

400

Shaft-hub connection Press

410

metallic intermediate layer

A

first direction of rotation

B

second direction of rotation

M

torque

M _nominal

rated torque

M *

amplitude

R

axis of rotation

m

torque curve

t

Time

0

NULL value

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 102005026713 A1 [0005]
• DE 102008035438 A1 [0005]

Claims (10)

Method for connecting a wave component ( 200 ) with a hub component ( 300 ) by a shaft-hub press connection ( 400 ), for which purpose at least one of the joining surfaces on the shaft component ( 200 ) and / or at the hub component ( 300 ) is coated with a thin metal layer before joining, and after the joining, at least one alternating rotary (A / B) training operation is performed in order to increase the bonding strength of the generated shaft-hub interference fit ( 400 ), characterized in that in the training process, the amplitudes (M *) of the alternating rotational load (A / B) below that of the shaft-hub press connection ( 400 ) to be transmitted nominal torque (M _nominal ). A method according to claim 1, characterized in that the amplitudes (M *) of the alternating rotational load (A / B) less than 75%, preferably less than 50%, more preferably less than 45% and in particular less than 40% of the rated torque (M _nominal ). A method according to claim 1 or 2, characterized in that the alternating rotational load (A / B) is low frequency and preferably less than 10 Hz and in particular in the range between 2 Hz and 8 Hz. Method according to one of the preceding claims, characterized in that the wave component ( 200 ) and the hub component ( 300 ) are formed of different materials. Method according to one of the preceding claims, characterized in that the wave component ( 200 ) is formed from a metal casting material, preferably from a cast iron material and in particular from a malleable cast iron. Assembly ( 100 ) comprising a wave component ( 200 ) and a hub component ( 300 ) produced by a shaft-hub press connection (10) produced by a method according to any one of the preceding claims 1 to 5 ( 400 ) are rotatably connected to each other. Assembly ( 100 ) for an axle differential of a motor vehicle, in particular a passenger car, comprising a differential housing ( 200 ) and a drive wheel ( 300 ), wherein the differential component forming the shaft component ( 200 ) and the hub component forming the drive wheel ( 300 ) produced by a method according to any one of the preceding claims 1 to 5 shaft-hub press connection ( 400 ) are rotatably connected to each other. Assembly ( 100 ) according to claim 7, characterized in that the drive wheel ( 300 ) directly on the outside of the differential case ( 200 ) is arranged. Assembly ( 100 ) according to claim 7 or 8, characterized in that the differential housing ( 200 ) is formed of a cast iron material. Assembly ( 100 ) according to claim 7, 8 or 9, characterized in that it is in the shaft-hub-press connection ( 400 ) is a transverse compression bandage.

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