DE102014203948A1 - Axial positioning of a sun gear in a lightweight differential - Google Patents

Abstract

The invention relates to a planetary gear (1) having at least one sun gear (2), which has a toothed region (4) with external teeth (5), with at least one coaxial and rotatable to the sun gear (2) planet carrier (6), wherein between Planet carrier (6) and the sun gear (2) a sliding sleeve (13) is arranged, on the one hand an axial stop surface (15) for limiting an axial displacement of the sun gear (2) and on the other a hollow cylindrical radial stop surface (14) for limiting a radial displacement of the Sun gear (2), wherein at the sun gear (2) an axial stop (16) comes into contact with the axial stop surface (15) of the sliding sleeve (13) as needed, wherein the axial stop (16) in the axial direction of the toothed region (4) of the Sun gear (2) is spaced away.

Description

Field of the invention

The invention relates to a planetary gear with at least one sun gear, which has a toothed region with external teeth, with at least one coaxial and rotatable to the sun gear arranged planet carrier, between the planet carrier and the sun gear, a sliding sleeve is arranged, on the one hand a stop surface for limiting a Axialverlagerung of the sun gear has and on the other hand has a hollow cylindrical radial stop surface for limiting a radial displacement of the sun gear, wherein further on the sun gear an axial stop to come in contact with the axial stop surface of the sliding sleeve is available.

Usually planetary gear are stored on a stationary housing. In one embodiment of a planetary gear as a differential, so-called O-arrangements have been proven in recent years. These have advantages in terms of stability over previously used classical X-arrays.

Planetary gear are, for example, from the DE 10 2009 032 286 A1 known. The planetary gear disclosed therein has two sun gears, each of which sun gear meshes with a set of planet gears carried by a planet carrier. In this case, the sun gears are radially centered by the forces acting during operation with the planetary gears tooth forces. A disadvantage of this embodiment is that the centering is not or only insufficiently ensured in the load-free state, so that the position of the sun gears can get very far from the radial center position. In addition, in spite of the effective tooth forces imbalances may occur on the sun gears during operation. In addition, misalignment between the sun and planet carrier are possible. All this leads to increased wear and increased noise. This is all the more true when large forces between planetary gears and sun gears are transmitted, as in particular in a differential.

Similar gear combinations are, for example, from the DE 10 2008 027 992 A1 known. There, a drive device for motor vehicles with four-wheel drive is disclosed. This drive device is provided for the transverse installation, in which an axle differential and an intermediate differential are structurally combined formed in a transmission housing, wherein the differentials are designed as a helical planetary gear, with a first land as input element of the Zwischenachsdifferenzials, via the planet gears to the sun gear which abrades an output element and an outer wheel on the axle differential as the other output element, wherein the outer wheel abrades on the web of the axle differential and the planet gears on output elements to the axle shafts. This document advocates that the two differentials are geared so that they have a common bridge. A spur gear differential and a planetary gear as a superposition stage are thus combined. However, torque is derived from a front axle to a rear axle differential of the motor vehicle via the superposition stage.

Another planetary gear is also from the US 4574658 However, in which a planetary gear is combined with a spur gear stage. A sun gear of the planetary gear is driven by an additional spur gear section by a separate pinion from the planetary gear.

Also the pamphlets DE 2031654 A1 and GB 1212630 A disclose gearbox combinations in which different gear stages are interconnected. In particular, inter alia, a torsionally rigid connection is disclosed, which represents a gear stage, with two cooperating transmission elements, each carrying a ring member having an axially extending cylindrical extension and which produces a torsionally rigid coupling with the ring element of the other transmission element, wherein the ring elements made of sheet metal are made and have in their cylindrical extension axially extending, tooth-like indentations, which are in the manner of a partial toothing in mutual engagement.

That parts of planetary carriers can also be welded together, is also from the pamphlets DE 103 33 880 A1 and DE 103 33 879 A1 known.

A similar transfer case for motor vehicles is also from the DE 10 2007 017 185 B4 known, in which a transfer case for motor vehicles, is disclosed with a driven differential, which abrades on balancing elements on two output shafts, wherein the output torque to the output shafts by means of a planetary gear formed by the output shafts indirectly or directly drivably connected via superposition gear and a coupled drive machine is changeable and wherein the translation of the superposition gear is designed such that when synchronizing the output shafts, the prime mover is stationary. To improve the redistribution in terms of precision and faster response with respect to the output torques in a structurally favorable construction of the Superposition gear and the prime mover is proposed in this document that the superposition gear at least one interacting with the differential torque reducing epicyclic gear is connected upstream.

However, the previously known planetary gear and gear combinations have the disadvantage that they consist of many components and require a relatively large amount of space. The production is relatively expensive and the installation relatively expensive.

The currently favored, current design of lightweight differentials is designed so that the main storage has a so-called O-arrangement, i. a differential housing is fixed to outer rings of a rolling bearing, wherein the sun gears are axially guided via separate support sleeves. This is certainly not a disadvantage, but from today's perspective is an optimum dar. However, there are still requirements for classic X-arrangements, despite certain disadvantages in terms of friction and stiffness.

It is the object of the present invention to minimize or even eliminate friction disadvantages and stiffness loss, in particular in the case of a classic X-bearing arrangement, that is to say when installing roller bearings, in particular angular ball bearings or tapered bearings in an X arrangement.

An alternative construction with appropriate support of the sun as previously known is desired. It should be found storage locations to achieve maximum support width, and axially spaced as far as possible from each other. As a result, the axial positioning of the sun gears / suns becomes problematic, so that a new solution can be found right here. This is the problem underlying the invention.

Disclosure of the invention

This object is achieved in a generic planetary gear transmission according to the invention in that the axial stop of the sun gear in the axial direction of the toothed portion of the sun gear is spaced away. Such a design of an axial starting geometry is found, which means no high weight gain. The sun wheel can still build very easily.

If the weight does not play a major role, a simple paragraph in the sun can also be provided in general. However, this inevitably leads to more weight on the sun gear, which is, however, avoidable in this invention case shown here. An axial support of a sun gear in a differential with a spur gear teeth and a main bearing in X-arrangement is thus targeted.

Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

Thus, it is advantageous if the distance of the axial stop from the rolling bearing nearest portion of the outer toothing of the sun gear is more than the tooth length in the region of the outer toothing of the sun gear, preferably 1.5, 1.8, 2.0, 2.2, 2.5 up to 3.0 times bigger. It is also advantageous if the said distance corresponds approximately to the inner diameter of the sun gear in the region of the shaft of the sun gear.

It is also advantageous if the planet carrier is composed of two planetary carrier halves, which are preferably designed symmetrically to each other, so are configured mirror-symmetrical to a transverse plane and has an at least partially extending in the axial direction transition region between a connection region on a spur gear and a bearing region for the rolling bearing , The transition region may be formed obliquely to the radial and axial directions.

It is also of particular advantage, if the sliding sleeve is made of case hardening steel and / or case hardened. The wear can be minimized.

Furthermore, it is advantageous if the sliding sleeve is designed as a deep-drawn sheet metal part manufactured in particular without cutting. The production times can be reduced thereby, which has a positive effect on the manufacturing costs.

Thus, even with frequent rotation of the shaft of the sun gear relative to the planet carrier, especially in the case of a differential, no great wear occurs, it is advantageous if the radial stop surface has friction bearing properties for low-friction bearings of a shaft portion of the sun gear.

It is advantageous if a lubricant reservoir or more lubricant reservoirs on the shaft of the sun gear facing side of the radial stop surface forming sliding sleeve end portion is / are present. The friction between the friction partners can then be reduced.

It is also advantageous for the lubricant reservoirs to be designed as blind holes or preferably non-cutting through holes or at least partially grooves / notches extending in the axial direction, such as meandering slots are. Oil pockets and oil reservoirs can then be maintained. The through holes can also be designed as bores.

The sliding properties can be further improved if a Kunststoffgleithohlzylinder is present radially between the sliding sleeve and the shaft of the sun gear, as in the manner of a Gleitringeinsatzes.

The assembly is simplified if the axial stop is formed by the shaft of the sun gear (preferably integral or monolithic). Alternatively, in particular to save weight, it is advantageous if the axial stop of one of the sun gear e.g. Substitute same or differently designed separate or separate (distance) ring is provided.

A batch-wise matching of the individual components is facilitated if the (distance) ring which can be formed as a tuning ring rests without clearance on a shoulder (on the shaft) of the sun gear.

In particular, the invention also relates to the case where the planetary gear is designed as a (lightweight) spur gear differential.

It is advantageous if the lubrication recesses extend without interruption from a starting region to an axially offset end region or are interrupted by a reinforcing web.

If the lubricating recesses are formed as a continuous groove or a plurality of reinforcing webs is present, which divide the lubricating recesses into individual lubrication pockets, so a further advantageous embodiment can be provided.

It is also advantageous if the sliding sleeve is produced without cutting, in particular a (metal) sheet-metal component, e.g. made of case-hardening steel, is.

It has proven to be expedient if the lubricating recess is formed as a through hole, since it extends from a radially inner surface to a radially outer surface.

The lubrication recess may also be attached as a through hole from the inside out.

The sliding sleeve is also used in the planet carrier / differential cage non-positively and / or positively, preferably pressed.

It is advantageous if the planet carrier is connected to a spur gear, for example on the radially outer side.

The lubrication pocket or lubrication pockets may extend substantially circumferentially.

The construction is also characterized by the non-cutting or machining of the (spacer) ring, which is pressed onto the cylindrical part of the sun gear, so the shaft.

The bearing sleeve, which is mounted inside the bearing seat of the housing, thus serves as a radial and axial sliding bearing. Therefore, the bearing sleeve is also referred to as a sliding sleeve.

The side surface of the sun gear and the position of the (spacer) ring are axially spaced at least about 5mm, 7.5mm, 10mm or 12.5mm apart.

It can be used as a differential with a main bearing in X-arrangement. In the embodiment as differential gear / differential gear, in particular as Stirnraddifferenzialgetriebe, two sun gears can be arranged directly next to each other, wherein the balancing teeth preferably has two toothing planes. That is, the outer teeth of the one sun gear is radially outward than the outer teeth of the other sun gear, but the same gear module is present in both external gears. The toothed contact between the planetary gears acting as differential gears is preferably present radially above the smaller sun.

The invention ultimately relates to a differential gear, in particular a lightweight differential. It is further developed classic X-arrangement of a conventional lightweight differential so that a lightweight axial start-up geometry is made possible. The starting geometry is designed as a ring, which is arranged on the cylindrical part of the sun.

The invention will be explained in more detail with the aid of a drawing. Here, a first embodiment is considered in more detail. Show it:

1 a longitudinal section through an inventive, designed as Leichtbaustirnraddifferenzial planetary gear,

2 an increase in the area II 1 .

3 a perspective view of the in the 1 and 2 used sliding sleeve between a planet carrier half and a shaft of a sun gear, in particular radially in between, and

4 in the axial stop with the sliding sleeve 3 rung (distance) ring in singular perspective representation.

The figures are merely schematic in nature and are only for the understanding of the invention. The same elements are given the same reference numerals.

In 1 is a first planetary gear according to the invention 1 shown. The planetary gear has at least one sun gear 2 on. To be precise, there are two sun gears 2 available. Each sun gear meshes with a planetary gear 3 of which one in 1 is shown. Depending on a planetary gear of one for the one sun gear 2 provided planetary gear meshes with another planetary gear of the other planetary, which come into contact with the other sun gear 2 is provided. The respective planet wheels 3 touch each other in a transverse plane through the circumferentially smaller sun gear 2 ,

Each of the sun wheels 2 has a gearing area 4 on. In the gearing area 4 is an external toothing 5 available. The sun wheels 2 are coaxial and rotatable within a planetary carrier 6 arranged. The planet carrier 6 has a first planet carrier half 7 and a second planet carrier half 8th on. Through both planet carrier halves 7 and 8th protrudes a hollow bolt 9 on which the planetary gears 3 are stored. The hollow bolt 9 is through a bearing sleeve 10 in the respective planet carrier half 7 respectively. 8th stored. The planet carrier 6 has a transition region indicated by the reference numeral 11 is marked. This transition area 11 is an axial extension of the planet carrier 6 ,

Every sun wheel 2 has a shaft 12 on, in contact with a sliding sleeve 13 stands. The sliding sleeve 13 has an inner radial stop surface 14 on. The sliding sleeve 13 but also has an axial stop surface 15 on. This axial stop surface 15 the sliding sleeve 13 is to come into contact with an axial stop 16 intended.

The axial stop 16 is as a (distance) ring 17 educated. The (distance) ring 17 can also be designed as a tuning ring, so have different thicknesses. This facilitates a batch-wise tuning. The contact of the radial stop surface 14 the sliding sleeve 13 from the peripheral surface of the shaft 12 of the sun wheel 2 is also in 2 clearly visible. There is also seen that the (distance) ring 17 on a heel 18 of the shaft 12 of the sun wheel 2 without play. The non-cutting manufactured, deep-drawn sliding sleeve 13 is normally spaced from the contact surface 19 on the sliding sleeve 13 facing side of the (distance) ring 17 ,

The (distance) ring can be made by cutting or cutting and on the shaft 12 be pressed on. Between the sun wheel / the sun 2 and the (distance) ring 17 there is a press federation.

In 3 is the hollow design of the sliding sleeve 13 easy to see, as well as the radial stop surface 14 and the axial stop surface 15 ,

In 4 is the solid manufactured (distance) ring 17 to recognize with a predetermined thickness. It is possible that the thickness is kept variable, but is preferably a constant thickness.

Coming back to 1 is the distance of the axial stop 16 from the gearing area 4 with the reference number 20 characterized.

LIST OF REFERENCE NUMBERS

1

 planetary gear

2

 sun

3

 planet

4

 toothed area

5

 external teeth

6

 planet carrier

7

 first planet carrier half

8th

 second planet carrier half

9

 hollow pin

10

 bearing sleeve

11

 Transition region of the planet carrier

12

 Shaft of the sun wheel

13

 sliding sleeve

14

 Radial stop surface of the sliding sleeve

15

 Axial stop surface of the sliding sleeve

16

 axial stop

17

 (Distance) Ring

18

 paragraph

19

 Contact surface of the (distance) ring

20

 distance

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 102009032286 A1 [0003]
• DE 102008027992 A1 [0004]
• US 4574658 [0005]
• DE 2031654 A1 [0006]
• GB 1212630 A [0006]
• DE 10333880 A1 [0007]
• DE 10333879 A1 [0007]
• DE 102007017185 B4 [0008]

Claims (10)

Planetary gear ( 1 ) with at least one sun gear ( 2 ), which has a gearing area ( 4 ) with an external toothing ( 5 ), with at least one coaxial and rotatable to the sun gear ( 2 ) arranged planet carrier ( 6 ), whereby between planet carriers ( 6 ) and the sun wheel ( 2 ) a sliding sleeve ( 13 ) is arranged, which on the one hand an axial stop surface ( 15 ) for limiting an axial displacement of the sun gear ( 2 ) and on the other hand, a hollow cylindrical radial abutment surface ( 14 ) for limiting a radial displacement of the sun gear ( 2 ), wherein at the sun gear ( 2 ) an axial stop ( 16 ) come into contact, if necessary, with the axial stop surface ( 15 ) of the sliding sleeve ( 13 ), characterized in that the axial stop ( 16 ) in the axial direction of the toothed area ( 4 ) of the sun wheel ( 2 ) is spaced away. Planetary gear ( 1 ) according to claim 1, characterized in that the sliding sleeve ( 13 ) consists of case-hardened steel and / or case-hardened. Planetary gear ( 1 ) according to one of claims 1 or 2, characterized in that the sliding sleeve ( 13 ) Is designed as a chipless manufactured deep-drawn sheet metal part. Planetary gear ( 1 ) according to one of claims 1 to 3, characterized in that the radial stop surface ( 14 ) Sliding bearing properties for the low-friction bearing of a shank region ( 12 ) of the sun wheel ( 2 ) having. Planetary gear ( 1 ) according to claim 4, characterized in that a lubricant reservoir or a plurality of lubricant reservoirs on the shaft ( 12 ) of the sun wheel ( 2 ) facing side of the radial stop surface ( 14 ) forming sliding sleeve section is / are present. Planetary gear ( 1 ) according to claim 5, characterized in that the lubricant reservoirs are formed as blind holes or through holes or in the axial direction extending grooves / notches / slots. Planetary gear ( 1 ) according to one of claims 1 to 6, characterized in that radially between the sliding sleeve ( 13 ) and the shaft ( 12 ) of the sun wheel ( 2 ) a Kunststoffgleithohlzylinder is present. Planetary gear ( 1 ) according to one of claims 1 to 7, characterized in that the axial stop ( 16 ) from the shaft ( 12 ) of the sun gear or is provided by a separate from the sun / isolated (distance) ring. Planetary gear ( 1 ) according to claim 8, characterized in that the formable as a tuning ring (spacer) ring on a paragraph ( 18 ) of the sun wheel ( 2 ) without play. Planetary gear ( 1 ) according to one of claims 1 to 9, characterized in that the planetary gear ( 1 ) is designed as a (lightweight) spur gear differential.

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