DE102011007455A1 - Axle for motor vehicle, has differential portion which is formed as spur gear in planetary design, while differential gears are arranged at planet wheels of approximately same planetary pitch diameter - Google Patents

Abstract

The axle has differential portion which is in drive connection with two-speed transmission with reverse rotation. Several planetary gears are arranged in the power flow between differential portion and drive unit (A). The differential portion is formed as a spur gear in planetary design, and differential gears are arranged at planet wheels of approximately the same planetary pitch diameter. An independent claim is included for control unit for switching of two-speed gearbox.

Description

Field of the invention

The invention relates to a transaxle for a motor vehicle with a differential in drive connection with a two-speed transmission with reverse rotation, which is arranged in the power flow between the differential and a drive unit and having one or more planetary gear stages. The invention further relates to adjusting means for switching such a two-speed transmission.

Out US 7,703,353 B2 is such a final drive known. There, a drive unit is described in which an output is coupled to an input through a first gear set that selectively rotates with respect to a power transmission output in the forward direction or in the reverse direction, the output being drivably connected via a differential mechanism to two sets of vehicle wheels.

Further describes DE 198 41 159 C2 a drive unit for a motor vehicle with an electric drive in a coaxial arrangement, in which a bevel gear differential is combined with a planetary gear.

In such axle transmissions, the problem is that they are complex and require a lot of space.

Summary of the invention

The invention is therefore based on the object to simplify a transaxle of the aforementioned type in terms of its structure and to make space-saving. The object is solved by the features of claim 1 and alternatively by the features of claim 10.

It is proposed that in a final drive of the aforementioned type, the differential be designed as Stirnraddifferenzial in planetary design and at least one set of differential gears and at least one set of planet gears at least one planetary gear each to the same or approximately the same pitch circle diameter. In this way it is possible compactly to combine one or more planetary gear compactly with a differential gear space to create a simple axle assembly with reversal of direction. In this case, in particular by a large number of identical parts, the construction is greatly simplified and at the same time the manufacturing and assembly costs are significantly reduced.

The construction can be further simplified if at least one set of differential gears is arranged with at least one set of planet gears on common axles. It is also conceivable that at least two sets of planet gears form common axles.

In a particularly preferred embodiment of the invention, the two-speed transmission comprises a first planetary gear with a first set planetary gears, wherein the first set planetary gears and a set of differential gears are each arranged on the same or approximately the same pitch circle diameter.

In an alternative embodiment of the invention, the two-speed transmission on a first planetary gear with a first set of planetary gears and a second planetary gear in a coaxial design. Preferably, in this case, the second planetary gear as Doppelplanetenradstufe in a radial arrangement with a radially inner set planetary gears and with a radially outer set planetary gears formed According to the planetary gear sets and Ausgleichsradsätze are arranged on two pitch diameters. Preferably, a first set of differential gears and the first set planetary gears and the radially outer set planetary gears each on a first pitch circle diameter and the radially inner set planetary gears and the second set differential gears of the differential are each arranged on a second pitch circle diameter.

According to a further particularly preferred embodiment of the invention, a third planetary gear with a third set of planet gears is arranged coaxially with the first and the second planetary gear. Preferably, the first set planetary gears and the radially outer set of planetary gears and a first set of differential gears each on the first pitch diameter and the radially inner set planetary gears and the third set planet gears and a second set of differential gears are each arranged on a second pitch circle diameter.

Preferably, the first planetary gear further comprises a first sun gear and a first ring gear, wherein the first set planetary gears with the first sun gear and with the first ring gear is engaged in the process are preferably the first set of planetary gears from a first Planetenradsteg and the differential gears of the differential of a second Planet wheel carried. Preferably, the first sun gear is drivably connected to the drive unit and by adjusting means alternately the first Planetenradsteg and the first ring gear with the second Planetenradsteg connectable. At the same time, the first ring gear and the first planetary gearwheel may be locked in a rotationally fixed manner at the same time by the adjusting means, for example by fixing the ring gear to a stationary one Gearbox. As a result, the output at the planetary gear stage to the differential gear can be made either via the planetary gear or via the ring gear planetary gear. At the same time a reversal of rotation is achieved at the output of the planetary gear or the drive of the differential. The required for switching actuators of the two-speed transmission can be formed for example by the adjusting means described below.

Preferably, a total ratio of the first planetary gear in the slow of i = number of teeth first ring gear / number of teeth first sun gear is about equal to 3 in reverse and about equal to 4 in forward gear.

Preferably, a total ratio of i = -3.9 in reverse gear and of i = 4.9 in forward gear is provided on the first planetary gear. Preferably, the first planetary gear at the gear pairings in the end section has a profile coverage ε _α , formed by the ratio of engagement distance to Stirneingriffstellung of 1.75 and a jump coverage ε _β due to the inclination of the teeth, formed by the ratio of tooth width to axial pitch of 0.5 on.

Preferably, the second planetary gear (Doppelplanetenradstufe) further comprises a second sun gear and a second ring gear. In this case, the radially inner set of planetary gears with the second sun gear and in each case one planetary gear of the radially inner set of planetary gears engage in pairs with a planetary gear of the radially outer set planetary gears and this with the second ring gear. Preferably, first, radially inner and radially outer set of planetary gears are supported by a common first Planetenradsteg and the differential gears of the differential of a second Planetenradsteg which is drivably connected to the first Planetenradsteg. Preferably, the first sun gear of the first planetary gear and the second sun gear of the second planetary gear are connected to the drive unit. At the same time alternately the first ring gear and the second ring gear are rotatably arrettierbar by adjusting means. As a result, at the common first Planetenradsteg of the first and second planetary gear optionally a direction of rotation reversal based on the direction of rotation of the drive of the first and second sun gear is achieved. Preferably, the first and second Planetenradsteg are arranged coaxially with each other.

Preferably, the first planetary gear with a ratio i = number of teeth ring gear / number of teeth sun gear = 1.6 and the second planetary gear (double planetary gear) with a ratio i = number of teeth ring gear / number of teeth sun = 3.6 formed. The first planetary gear stage preferably has a profile coverage ε _α of 2 and a jump coverage ε _β of 1 and the second planetary gear stage has a jump coverage ε _β of 1.75 and a jump coverage ε _β of 0.5.

Preferably, the third planetary gear stage further comprises a third sun gear and a third ring gear, wherein the third set of planet gears is engaged with the third sun gear and with the third ring gear. Preferably, the third set planetary gears and the differential gear sets of the differential are supported by a common second planetary gear. Preferably, the third sun gear is drivably connected to the first Planetenradsteg. In this case, the differential on the common second Planetenradsteg the third planetary gear stage is driven. By the third planetary gear, the overall ratio can be varied at the two-speed transmission.

Preferably, in this case, the second Planetenradsteg also forms the differential case.

In this case, the difference between the ratio at the second planetary gear stage and the ratio at the third planetary gear stage is approximately 2. In this case, the third planetary gear stage is preferably designed with a ratio i = number of teeth third ring gear / number of teeth third sun = 1.9. The third planetary gear stage preferably has a profile coverage ε _α of 1.75 and a jump coverage ε _α of 0.5. At the two-speed gearbox or at the three planetary gear ratios while the same ratio is achieved in forward and reverse gear. This is preferably about 6 to 8 slow. Preferably, a total ratio of i = 7.5 in forward gear and i = -7.5 in reverse gear is achieved.

According to an independent idea of the invention adjusting means are provided for switching a two-speed transmission. According to the invention the adjusting means are designed as a coupling unit having two rotatably connected components. These are also connected switchable together in the axial direction back and forth. Preferably, the coupling unit is rotatably supported on a first component at the transmission input of the differential back and forth rotatably and alternately rotatably coupled with a Planetenradsteg and with a ring gear of a planetary gear. Preferably, the coupling unit is at the same time on a second component to a transmission range slidably supported back and forth rotationally fixed and alternately rotatably coupled to the ring gear and the Planetenradsteg coupled.

By the coupling unit according to the invention a simply constructed actuator for a two-speed circuit is created, which claimed at the same time little space. It can by means of simply reciprocating the coupling unit alternately 2 × 2 rotary transmission sections are each coupled simultaneously with a rotary or non-rotatable transmission range. Since the components of the coupling unit are arranged rotatably to each other, rotatable and non-rotatable transmission portions can be coupled simultaneously.

The coupling unit and the aforementioned transmission ranges can for interlocking rotationally fixed support and / or coupling toothed elements, for example, a spline having.

Preferably, the coupling unit on the first component back and forth slidably supported rotatably on the differential housing while selectively rotatably coupled to the first Planetenradsteg or with the first ring gear of the first planetary gear. Preferably, the coupling unit is at the same time on the second component back and forth displaceable on a non-rotatable transmission area, in particular a gear housing, rotatably supported and selectively rotatably coupled to the first ring gear or with the first Planetenradsteg. In this case, the differential in any construction, in particular as a spur gear in planetary design or as a bevel gear, executed.

Preferably, a spline is provided in each case on the first component and on the second component of the coupling unit as well as on the first ring gear and on the first planetary gear web. At this preferably the first component and second component is displaceable back and forth alternately on the first Planetenradsteg and the first ring gear rotatably pushed or plugged. At the same time the second component back and forth displaced alternately on the first ring gear and on the first Planetenradsteg pushed or plugged. The spline can be performed for example as external and internal teeth.

It is conceivable to apply sliding sleeve technology for realizing the two-speed shift.

Brief description of the drawings

Further features of the invention will become apparent from the following description and from the drawings, in which two embodiments of the invention are shown in simplified form. Show it:

1 a schematic representation of a transaxle according to the invention in a first embodiment,

2 a schematic representation of adjusting means in the axle drive 1 .

3 a schematic representation of a transaxle according to the invention in a second embodiment,

4 a schematic representation of the actuating means in the final drive 2 ,

Detailed description of the drawings

In 1 is schematically illustrated a transaxle according to the invention in a first example. The axle drive comprises a differential and a two-speed gearbox with reversal of direction of rotation, in this case a first planetary gear stage. Differential and first planetary gear are arranged coaxially and are in drive connection, wherein the planetary gear in turn by a drive unit A can be driven. The first planetary gear consists of a first sun gear 3 a first ring gear 4 and a first planetary gear set extending from a first planetary gear bridge 1 is worn and in the first sun 3 and the first ring gear 4 intervenes. The planetary gear 1 includes the Planetenradbolzen on which the planetary gears are supported by planetary gear bearings, and a box-like carrier on which the Planetenradbolzen are accommodated.

The differential is exemplified here as a spur gear differential planetary design and has two sun gears, each with an axle shaft 11 . 12 are connected, each driving a wheel of the motor vehicle. The sun gears are formed with different diameters and are each in engagement with a set of differential gears. Here, in pairs combing a differential gear of a set of differential gears and a differential gear of the other set of differential gears with each other. At the same time both Ausgleichsradsätze of a common second Planetenradsteg 2 carried, which also forms the differential housing and coaxial with the first Planetenradsteg 1 is arranged. In this case, the first set planet gears of the first planetary gear and a set of differential gears are each arranged on a pitch circle, as indicated schematically, with the same or approximately the same diameter. Here are the bearings of the first set planetary gears and the set of differential gears on the same or approximately the same pitch circle diameter.

At the first planetary gear is the first sun gear 3 drivably connected to the drive unit A. Optionally, via a first brake B1, the first ring gear 4 or via a second brake B2 of the first Planetenradsteg 1 fixable. At the same time are the first Planetenradsteg 1 over a first clutch K1 or the first ring gear 4 via a second clutch K2 with the second Planetenradsteg 2 coupled. Is the first ring gear 4 determined via the first brake B1, the output takes place at the first planetary gear via the first Planetenradsteg 1 , Here is the second Planetenradsteg 2 or the differential housing with the first Planetenradsteg 1 drivably connected by the first clutch K1. Will, however, the first Planetenradsteg 1 determined by the second brake B2, the output at the first planetary gear via the first ring gear 4 , whereby at the output a direction of rotation reversal with respect to the direction of rotation of the first sun gear 3 is reached. Here is the ring gear 4 via the second clutch K2 with the second Planetenradsteg 2 or drivably connected to the differential housing. In this way, the differential on the upstream first planetary gear stage of the drive unit A can be driven either in a forward gear or in the opposite direction in a reverse gear. At the first planetary gear thus two switchable gears are realized with reversal of direction.

Preferably, the difference in the ratio between forward and reverse is equal to one. The overall ratio of the two-speed transmission, here the first planetary gear, is preferably at least three slower. In forward gear, a total ratio of about i = 4 and in reverse a ratio of about i = -3 is provided. In the specific embodiment, the ratio i = number of teeth ring gear / number of teeth sun gear = 3.9 at the first planetary gear stage. In this case, the first planetary gear has a profile coverage ε _α of 1.75 and a jump coverage ε _β of 0.5. The overall ratio is i = -3.9 in reverse and i = 4.9 in forward gear.

The drive unit A can be designed either as an internal combustion engine with gearbox or as an electric motor or as any other type of machine for generating torques. Among other things, stepless concepts are conceivable, such. As a CVT transmission.

2 schematically shows a possible embodiment of the adjusting means for the realization of the two-speed circuit when the vehicle is in an axle drive according to the embodiment in 1 , For this purpose, a coupling unit of two components 9 . 10 intended. The components 9 . 10 are rotatable on a schematically indicated thrust bearing and at the same time together axially displaceable back and forth. The first component 9 is at the second Planetenradsteg 2 or on the differential housing back and forth slidably supported rotationally fixed, and at the same time by axial back and forth shifting alternately with the first Planetenradsteg 1 and with the first ring gear 4 rotatably coupled. This is the second Planetenradsteg 2 or the differential housing optionally through the first Planetenradsteg 1 or by the first ring gear 4 drivable. At the same time, the second component 10 the coupling unit on an indicated rotationally fixed transmission range, such as a housing, slidably supported back and forth rotatably. By moving the coupling unit back and forth also passes the second component 9 . 10 alternately with the first ring gear 4 and with the first Planetenradsteg 1 each rotatably engaged. Here are first and second component 10 rotatably mounted to each other, as indicated schematically by the thrust ball bearing. The first component takes over 9 the coupling unit the function of the axle in 1 indicated clutches K1 and K2, while the function of the there indicated brakes B1 and B2 through the second component 10 the coupling unit is taken over. For coupling the first and second components 9 . 10 with the first Planetenradsteg 1 and the first ring gear 4 For example, in each case a spline can be provided with internal and external teeth.

At the in 3 illustrated second embodiment of an axle according to the invention, the differential upstream two-speed transmission in addition to the first planetary gear includes a coaxial second and a coaxial third planetary gear. The trained as Doppelplanetenradstufe in a radial arrangement second planetary gear has a second sun gear 5 and a second ring gear 6 and a Doppelplanetenradstufe with a radially inner and a radially outer set planetary gears. The planetary gear sets are from the common first Planetenradsteg 1 carried. The planetary gears of the double planetary gear are radially inward with the second sun gear 5 and in pairs with each other and radially outward with the second ring gear 6 engaged. At the same time are the first sun wheel 3 and the second sun wheel 5 drivably connected to the drive unit A.

The third planetary gear includes a third sun gear 7 and a third ring gear 8th as well as a third set of planet gears, from a second planetary gear 2 is worn and with the third sun 7 and with the third ring gear 8th are engaged. Here is the third ring gear 8th relative to an example indicated non-rotatable transmission range, such as a housing set. The third set of planetary gears and the two differential gear sets of the differential are from the common second Planetenradsteg 2 carried. In this way, the differential is over the common second Planetenradsteg 2 drivable. Here, the second Planetenradsteg forms 2 at the same time the differential housing or the differential cage.

According to the invention in the second embodiment, planetary gear sets and Ausgleichsradsätze are arranged on two pitch circle diameters. Here, first and radially outer set of planetary gears and a first set of differential gears are each arranged on a larger pitch circle with the same or approximately the same diameter, as indicated schematically. Radial inner and third set of planet gears and the second set of differential gears each form a smaller circle of equal or approximately equal diameter. As a result, the Planetenradlagerungen from the first and radially outer set planetary gears and the first set of differential gears on a first pitch diameter and the Planetenradlagerungen of radially inner and third set of planetary gears and the second set of differential gears are each on a second pitch circle diameter.

In this case, on the one hand, the first and the radially outer set planetary gears and on the other hand, the third set planetary gears and a set of differential gears each have common axles, d. H. in the first case, the planetary gears or in the second case, the planet gears and the differential gears are arranged in pairs on a common wheel axle.

Drive side is the third sun gear 7 with the first Planetenradsteg 1 connected to the first and second planetary gear stage. At the first and second planetary gear are the first and the second ring gear 4 . 6 optionally lockable via the brakes B1 and B2 to an indicated rotationally fixed transmission range, for example a housing. This is the common output of the first and second planetary gear on the common first Planetenradsteg 1 a direction of rotation reversal with respect to the drive-side rotational direction of the first and second sun gear 3 . 5 reached. The first and second planetary gear thus realize two switchable gears with reversal of direction, while at the third planetary gear an additional translation can be achieved.

Preferably, the difference in the ratio between the second and the third planetary gear is about equal to 2. Preferably, in forward gear is a translation to the slow of about i = 6 to i = 8 and in reverse, a translation of about i = -6 to i = -8 intended. In the specific embodiment, the total ratio of the two-speed transmission is i = 7.5 in forward gear and i = -7.5 in reverse. The ratio at the first planetary gear is i = number of teeth ring gear / number of teeth sun gear = 1.6 and at the second planetary gear (double planetary gear) i = 3.6 and at the third planetary gear i = 1.9. In this case, the first planetary gear have a profile coverage ε _α of 2 and a jump coverage ε _β of 1 and the second and the third planetary gear each have a profile coverage ε _α of 1.75 and a jump coverage ε _β of 0.5.

The axle drive has a clutch unit which is axially displaceably supported in a rotationally fixed manner on an indicated rotationally fixed transmission region, for example a housing ( 4 ). By shifting the coupling unit back and forth, it alternately reaches the first ring gear 4 and the second ring gear 6 rotatably engaged, for example, each at a spline. As a result, either first or second ring gear 4 . 6 fixable on non-rotatable gearbox.

LIST OF REFERENCE NUMBERS

1

Planetenradsteg

2

Planetenradsteg

3

sun

4

ring gear

5

sun

6

ring gear

7

sun

8th

ring gear

9

component

10

component

11

axle shaft

12

axle shaft

A

drive unit

B1

brake

B2

brake

K1

clutch

K2

clutch

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

• US 7703353 B2 [0002]
• DE 19841159 C2 [0003]

Claims (10)

Achsgetriebe for a motor vehicle with a differential in drive connection with a two-speed gearbox with reverse rotation, which is arranged in the power flow between the differential and a drive unit (A) and one or more planetary gear, characterized in that the differential as a spur gear planetary design is formed and arranged at least one set of differential gears and at least one set of planetary gears at least one planetary gear on the same or approximately the same pitch circle diameter. Axle drive according to claim 1, characterized in that at least one set of differential gears and at least one set planetary gears are arranged on common axles. Axle drive according to claim 1 or 2, characterized in that a first planetary gear is provided with a first set planetary gears and this and a set of differential gears are arranged on the same or approximately the same pitch circle diameter. Axle drive according to one of claims 1 to 3, characterized in that a first planetary gear and a second planetary gear in coaxial design are arranged and the first planetary gear a first set of planetary gears and the second planetary gear as Doppelplanetenradstufe in a radial arrangement a radially inner and a radially outer set Planet wheels, wherein the first and the radially outer set planetary gears on a first pitch circle diameter and the radially inner set planetary gears and the second set of differential gears are arranged on a second pitch diameter. Axle drive according to one of claims 1 to 4, characterized in that a third planetary gear with a third set planetary gears is arranged coaxially to the first and second planetary gear and the radially inner set planetary gears, the third set of planetary gears and the second set of differential gears on the same or approximately the same pitch circle diameter are arranged. Axle drive according to one of claims 1 to 5, characterized in that the first planetary gear further comprises a first sun gear ( 3 ) and a first ring gear ( 4 ), wherein the first set of planet gears from a first Planetenradsteg ( 1 ) and the first set of planet gears with the first sun gear ( 3 ) and with the first ring gear ( 4 ), the first sun gear ( 3 ) is drivably connected to the drive unit (A) and the differential gears of a second Planetenradsteg ( 2 ) are supported, wherein by adjusting means alternately the first Planetenradsteg ( 1 ) and the first ring gear ( 4 ) with the second Planetenradsteg ( 2 ) connectable and at the same time alternately the first ring gear ( 4 ) and the first planetary gear ( 1 ) are rotatably durable. Axle drive according to one of claims 1 to 6, characterized in that the first planetary gear further comprises a first sun gear ( 3 ) and a first ring gear ( 4 ), wherein the first set of planet gears with the first sun gear ( 3 ) and with the first ring gear ( 4 ), and the second planetary gear stage further comprises a second sun gear ( 5 ) and a second ring gear ( 6 ) and the radially inner set planetary gears with the second sun gear ( 5 ) and in each case a planetary gear of the radially inner set in pairs with a planetary gear of the radially outer set and this with the second ring gear ( 6 ) is engaged and first, radially inner and radially outer set planetary gears of a common first Planetenradsteg ( 1 ) and the differential gears of a second Planetenradsteg ( 2 ), which is drivably connected to the first Planetenradsteg, and the first sun gear ( 3 ) and the second sun gear ( 5 ) each connected to the drive unit (A) and alternately the first ring gear ( 4 ) and the second ring gear ( 2 ) are rotatably durable by adjusting means. Axle drive according to one of claims 1 to 7, characterized in that the third planetary gear stage further comprises a third sun gear ( 7 ) and a non-rotatably arranged third ring gear ( 8th ), wherein the third set of planetary gears with the third sun gear ( 7 ) and with the third ring gear ( 8th ) and the third set planetary gears and differential gears of a common second Planetenradsteg ( 2 ) and the third sun gear ( 7 ) with the first planetary gear ( 1 ) is drivably connected. Axle drive according to one of claims 1 to 8, characterized in that the second Planetenradsteg ( 2 ) at the same time forms the differential housing. Adjusting means for switching a two-speed transmission with direction reversal in a final drive of a motor vehicle, wherein the two-speed transmission has one or more planetary gear and is in driving connection with a differential, characterized in that a coupling unit is provided, the two rotatable and at the same time together in the axial direction back and forth connected components ( 9 . 10 ), wherein a first component ( 9 ) rotatably supported on the transmission input of the differential back and forth rotatably and alternately with a Planetenradsteg ( 1 ) And with a ring gear of a planetary gear rotatably can be coupled and at the same time a second component ( 10 ) rotatably supported on a non-rotatable transmission area back and forth rotatably and alternately on the ring gear ( 4 ) and at Planetenradsteg ( 1 ) is rotatably coupled, wherein the form-fitting rotationally fixed support and coupling toothed elements are provided.

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