DE102020200168B4 - Gearbox concept of a manual transmission for electrically powered commercial vehicles as well as agricultural and construction machinery - Google Patents

Abstract

The present invention relates to a method for connecting a drive shaft (1) of an electric motor (30) to an output shaft (11), the method comprising the following steps: connecting a first gear wheel (2) firmly connected to the drive shaft (1) to a an intermediate shaft (4) firmly connected second gear wheel (5); Connecting a third (7) and a fourth (8) gear wheel, which are arranged on opposite sides of the second gear wheel (5) and are permanently connected to the intermediate shaft (4), with a fifth (9) and a sixth (10) gear wheel which are rotatably arranged on the output shaft (11); wherein the output shaft (11) is alternately firmly connected to the fifth (9) and the sixth (10) gear wheel. In addition, the present invention describes a switching device which can carry out said method.

Description

TECHNICAL PART

The present invention relates to the technical field of manual transmissions, in particular to the technical field of manual transmissions used in electric motors.

STATE OF THE ART

In commercial vehicles as well as agricultural and construction machinery with central drive, shiftable drive gears are used (mostly automated), which lead the drive power of a diesel engine to the differential of one or more driven axles. By choosing different gears, the diesel engine can be operated over a wide speed range with minimal fuel consumption.

In the course of the electrification of drive trains in vehicles, more and more electric motors with speeds> 10,000 rpm are used. In contrast to internal combustion engines, these high-speed electric motors can be operated over a much larger speed range with a high degree of efficiency.

This in turn makes it possible, for example, to replace a conventional diesel-powered automatic truck transmission with 8-16 gears (e.g. ZF-AS Tronic) with an electrically driven transmission with only two gears and a simple dog clutch.

The synchronization when changing gears is actively carried out by the electric motor, so that no synchronizer rings are required. The larger gear step with only two gears, however, requires an optimal arrangement of gears and clutch in the drive train in order to achieve the most compact possible design.

It is therefore an object of the present invention to provide a gearbox which is as simple and compact as possible and which can be used as a gearbox in an electrically driven motor vehicle.

DE 10 2015 205 905 A1 and WO 2014/086281 are the closest state of the art.

SHORT VERSION

The present invention is based on the idea that the two-speed connection between a drive shaft of an electric motor and an output shaft enables a compact and efficient connection.

In this publication, the term “firmly connected” is used to describe both the term “rotationally fixedly connected” and the term “integrally connected”

According to one embodiment of the present invention, a method for connecting a drive shaft of an electric motor to an output shaft is provided, the method comprising the following steps: connecting a first gear wheel fixedly connected to the drive shaft to a second gear wheel fixedly connected to an intermediate shaft; Connecting a third and a fourth gear wheel, which are arranged on opposite sides of the second gear wheel and are firmly connected to the intermediate shaft, with a fifth and a sixth gear wheel, which are rotatably arranged on the output shaft, the output shaft alternating with the fifth and the sixth gear is firmly connected.

According to one embodiment of the present invention, there is provided a drive assembly comprising an electric motor and a gearbox, the gearbox comprising: a first shaft including a first gear wheel directly connected to the electric motor; an intermediate shaft comprising a second, a third and a fourth gear wheel which are fixedly connected to the intermediate shaft; the second gear being engaged with said first gear, the third and fourth gears being disposed on opposite sides of the second gear; a third shaft including fifth and sixth gears, the fifth and sixth gears being rotatably disposed on the output shaft, and the fifth and sixth gears meshing with the third and fourth gears, respectively; a fastening device which is arranged between the fifth and the sixth gear wheel along the third shaft and is fixedly connected to the third shaft; wherein the fastening device is configured to alternately non-rotatably connect the third shaft to the fifth and sixth gearwheels.

Figure list

• 1 zeigt ein Getriebeschema eines Schaltgetriebes gemäß einer Ausführungsform der vorliegenden Erfindung;
• 2 zeigt eine dreidimensionale Darstellung des Schaltgetriebes gemäß einer Ausführungsform der vorliegenden Erfindung;
• 3 zeigt eine dreidimensionale schematische Schnittdarstellung des Schaltgetriebes, das entlang der Abtriebswelle geschnitten ist, gemäß einer Ausführungsform der vorliegenden Erfindung.

The present invention is described with reference to the accompanying figures, wherein like reference characters refer to like parts and / or to like parts and / or to corresponding parts of the system. To the figures:

• 1 shows a transmission diagram of a manual transmission according to an embodiment of the present invention;
• 2 shows a three-dimensional representation of the manual transmission according to an embodiment of the present invention;
• 3 shows a three-dimensional schematic sectional illustration of the gearbox, which is cut along the output shaft, according to an embodiment of the present invention.

DETAILED DESCRIPTION

In the following, the present invention will be described with reference to specific embodiments as shown in the accompanying figures. Nevertheless, the present invention is not limited to the particular embodiments described in the following detailed description and shown in the figures, but the described embodiments merely illustrate some aspects of the present invention, the scope of which is defined by the claims.

Other changes and variations of the present invention will be apparent to those skilled in the art. The present description thus includes all changes and / or variations of the present invention, the scope of which is defined by the claims.

Even if the advantages of this invention are described in relation to an application in an electric drive, it is clear to the person skilled in the art that similar advantages can also be achieved with a different type of drive.

1 shows a transmission diagram of a two-stage gearbox 100 with two gears according to an embodiment of the present invention.

The manual transmission 100 includes a first shaft 1 (from now on simply drive shaft 1 called), which is a first gear wheel 2 includes that with the drive shaft 1 is firmly connected.

It also includes the manual transmission 100 an intermediate shaft 4th , which comprises a second 5, a third 7 and a fourth 8 gear wheel connected to the intermediate shaft 4th are firmly connected. In particular, in this example are the gears 5 and 7th with the intermediate shaft 4th non-rotatably connected (shaft-hub connection). In contrast, the fourth is gear 8th with the intermediate shaft 4th so connected that the fourth gear wheel 8th integral with the intermediate shaft 4th is provided. It is clear to a person skilled in the art that, in an alternative embodiment, all three gear wheels with the intermediate shaft 4th can be connected non-rotatably.

In particular, the term “firmly connected” is used in this publication to describe both “non-rotatably connected” and “integrally connected”

The third gear 7th and the fourth gear 8th are on opposite sides of the second gear 5 arranged.

The manual transmission also includes 100 a third wave 11 (from now on simply output shaft 11 called), which comprises a fifth 9 and a sixth 10 gear wheel, the fifth 9 and the sixth 10 gear wheel rotatable on the output shaft 11 are arranged.

In addition, there is a fastening device 13th arranged between the fifth 9 and the sixth 10 gear wheel and the fastening device 13th is on the output shaft 11 is rotatably connected (preferably in one piece). The function of the fastening device 13th will be explained in detail in the course of the description.

The drive shaft 1 is about rolling bearings 3a , 3b stored in a housing. The rolling bearings 3a , 3b are preferably designed as employed angular contact ball bearings in an X-arrangement. The intermediate shaft 4th is also about rolling bearings 6a , 6b stored in the housing. The rolling bearings 6a , 6b are preferably designed as adjusted tapered roller bearings in an X-arrangement.

The output shaft 11 is also about rolling bearings 14a , 14b stored in the housing and via a rotary seal 15th sealed against the housing. The rolling bearings 14a , 14b are preferably designed as adjusted tapered roller bearings in an X-arrangement. The rotary seal 15th is preferably designed as a radial shaft seal.

The manual transmission 100 is by an electric motor 30th driven. The electric motor 30th drives the drive shaft 1 with the first gear wheel 2 that stuck to the drive shaft 1 connected. Preferably the first gear is 2 integral with the drive shaft 1 intended.

The first gear wheel 2 drives this non-rotatably with the intermediate shaft 4th connected second gear wheel 5 on. It is particularly advantageous that the second gear wheel 5 between the third and fourth gearwheels 7th , 8th is arranged to create a compact and symmetrical structure.

The one with the intermediate shaft 4th connected third and fourth gears 7th , 8th drive the fifth and sixth gearwheels, respectively 9 , 10 the output shaft 11 on.

The fifth and sixth gear wheels 9 , 10 are about needle rings 12a , 12b rotatable on the output shaft 11 stored. Thus, the fifth and sixth gear wheels 9 , 10 can be viewed as idler gears.

The output shaft 11 is alternated with the fifth 9 and the sixth 10 gear through the fastening device 13th non-rotatably connected.

The fastening device 13th includes a clutch hub 13th axially along the axis of the output shaft 11 is displaceable, but at the same time non-rotatably with the output shaft 11 connected is.

Depending on the gear selected, one of the two idler gears becomes 9 and 10 with the coupling hub 13th non-rotatably connected. The power transmission between the idler gears 9 and 10 and the clutch hub 13th takes place via a form-fitting, axially separable connection 17th . When connecting 17th can it be B. be a tooth clutch, a dog clutch or a synchronizer unit. A “Curvic Coupling” arranged at the end is preferably used.

On a distal section of the output shaft 11 is a gear flange 16 arranged, which enables the non-rotatable connection to a connecting structure, preferably to a cardan shaft.

The drive shaft 1 can optionally be fitted with a rotary seal 18th be fitted between the electric motor 30th and the first gear 2 is arranged. This rotary seal 18th not applicable if the electric motors already have their own rotary seal and the gear wheel is offered as a drive unit together with the electric motor.

The output shaft 11 can be optional (see dashed line of 1 ) with a rotary seal on both shaft ends 15th and a gear flange 16 be equipped. This is e.g. B. advantageous if both axles of a vehicle are to be driven.

2 shows a three-dimensional representation of the gearbox 100 . As in 2 shown, includes the manual transmission 100 furthermore two speed sensors 19th , 21 configured, the rotating speed of the intermediate shaft 4th and the output shaft 11 capture. The detected rotational speed can be used to actively change the speed of the electric motor 30th control when changing gears, so that the speed of the engaged idler gear 9 or. 10 with the speed of the output shaft 11 is synchronized.

It is not necessary to have the speed sensors 19th , 21 are arranged at the gearboxes. In an alternative embodiment, a person skilled in the art could also set the speeds on the engine 30th and on the output shaft 11 measure up. What is important, however, is that two speed signals are always required for synchronization.

3 shows a three-dimensional schematic sectional view of the gearbox 100 that runs along the output shaft 11 is cut. As in 3 can be seen is the coupling hub 13th driven by a dog clutch. In particular, the clutch hub 13th along the axis of the output shaft 11 by a switching device 20th driven so that the clutch hub connects to the fifth or sixth gear wheel 9 , 10 connects. The switching device comprises a servomotor, a spindle and a shift fork.

As in 3 can be seen, the power is transmitted between the idler gears 9 and 10 and the clutch hub 13th in this particular case by the toothing of a "Curvic Coupling" arranged on the face.

While the present invention has been described with reference to the above-described embodiments, it will be apparent to those skilled in the art that it is possible to implement various modifications, variations, and improvements of the present invention in light of the above-described teaching and within the scope of the appended claims without departing from the scope of the invention.

In addition, in order not to unnecessarily obscure the invention described, the areas that would be skilled in the art have not been described here.

Accordingly, it is intended that the invention not be limited by the specific illustrative embodiments, but rather by the scope of the appended claims.

Claims (9)

A method for connecting a drive shaft (1) of an electric motor (30) to an output shaft (11), the method comprising the following steps: connecting a first gear wheel (2) firmly connected to the drive shaft (1) to one on an intermediate shaft (4) firmly connected second gear wheel (5); Connecting a third (7) and a fourth (8) gear wheel, which are arranged on opposite sides of the second gear wheel (5) and are permanently connected to the intermediate shaft (4), with a fifth (9) and a sixth (10) gear wheel , which are rotatably arranged on the output shaft (11), wherein the output shaft (11) is alternately firmly connected to the fifth (9) and the sixth (10) gear wheel. A drive arrangement comprising an electric motor (30) and a gearbox (100), the gearbox (100) comprising: a first shaft (1) comprising a first gear wheel (2) directly connected to the electric motor (30); an intermediate shaft (4) which comprises a second (5), a third (7) and a fourth (8) gear wheel which are firmly connected to the intermediate shaft (4); said second gear wheel (5) engaging said first gear wheel (2), the third (7) and fourth (8) gear wheels being located on opposite sides of the second gear wheel (4); a third shaft (11) which comprises a fifth (9) and a sixth (10) gear wheel, wherein the fifth (9) and the sixth (10) gear wheel are rotatably arranged on the output shaft (11), and wherein the fifth ( 9) and the sixth (10) gear are in engagement with the third (7) and fourth (8) gear, respectively; a fastening device (13) which is arranged between the fifth (9) and the sixth (10) gear wheel along the third shaft (11) and is firmly connected to the third shaft (11); wherein the fastening device (13) is configured to connect the third shaft (11) alternately to the fifth (9) and the sixth (10) gear wheel. Drive arrangement according to Claim 2 , wherein each of said gear wheels (2, 5, 7, 8, 9, 10) of the gearbox (100) is a spur gear. Drive arrangement according to one of the Claims 2 or 3 wherein the fastening device (13) is a coupling hub which is axially displaceable and fixed in rotation with the third shaft (11). Drive arrangement one of the Claims 2 until 4th , wherein the gearbox (100) is a two-speed gearbox. Drive arrangement according to one of the Claims 2 until 5 wherein the manual transmission (100) comprises a switching device (20). Drive arrangement according to Claim 6 , wherein the gearbox (100) comprises two speed sensors (19, 21) which are configured to detect the speed of the first shaft (1) or the intermediate shaft (4) and the third shaft (11), wherein by means of the detected speeds, preferably by actively changing the speed of an electric motor, during the switching process of said switching device (20), the speed of the connected gear wheel (9 or 10) can be synchronized with the speed of the third shaft (11). Drive arrangement according to one of the Claims 2 until 7th , wherein a gear flange (16) is firmly connected to the third shaft (11) so that the third shaft (11) of the drive arrangement enables a non-rotatable connection to a connecting structure. Drive arrangement according to one of the Claims 2 until 8th , wherein the first shaft (1), the intermediate shaft (4) and the third shaft (11) are each supported in a housing by at least two roller bearings (3a, 3b, 6a, 6b, 14a, 14b).

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