WO2015058754A1

WO2015058754A1 - Lightweight differential with parking lock gearing

Info

Publication number: WO2015058754A1
Application number: PCT/DE2014/200487
Authority: WO
Inventors: Franz Kurth; Harald Martini; Thorsten Biermann
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2013-10-21
Filing date: 2014-09-19
Publication date: 2015-04-30
Also published as: DE102013221254A1

Abstract

The invention relates to a lightweight differential (1) with an input gear (3) for introducing torque and two output gears (27) for transmitting torque, wherein the output gears (27) are at least in part rotatably arranged inside a differential cage (5), at least one rolling bearing (13) engages the differential cage (5) in order to set the axial and/or radial position of the latter, and a ring provided for contacting the rolling elements (16) of the rolling bearing (13) comprises parking lock gearing (20) in at least one section.

Description

Name of the invention

Lightweight differential with parking lock toothing

description

Field of the invention

The invention relates to a lightweight differential with an input gear provided for torque introduction and two provided for torque output output gears, wherein the output gears at least partially se within a differential cage, such as a differential housing, which is also formed as a planet carrier rotatably, at least one roller bearing for axial and / or radial position determination of the differential cage acts on these.

The invention ultimately also relates to lightweight baudifferentials developed as spur gear differentials.

Vehicle transmissions are already known from the prior art, which are designed as differentials. For example, DE 101 31 735 A1 discloses a parking brake device for vehicle transmissions, which are arranged outside of the actual transmission on and in the region of the differential gear. For this purpose, a parking lock gear is mounted on a differential gear housing, in the gear gaps can engage an activated by an actuator locking lever. This is a different approach than is followed in, for example, DE 10 2009 036 986 B4, where a differential gear comprising a differential housing with an integrally formed axle drive wheel is disclosed there, further comprising a first part of the differential housing with a flange. see, by means of which the first part is locked or locked to the Achsantriebsrad on a second part of the differential gear housing comprising the Achsantriebsrad and a bearing, wherein it is particularly found that at least one window and at least one Schöpfrille radially in Achsantriebsrad adjacent to Storage are arranged.

While in DE 10 2009 036 986 B4 thus a parking lock toothing is disclosed in one piece with the differential, in a further document, namely DE 10 201 1 081 883 A1, a separate component is provided with a parking lock toothing and then fixed to the differential basket. Thus, for example, this latter publication discloses a differential for a motor vehicle, with a Drehmomenteinleitorgan, which is in operative relationship with a driven by the Drehmomenteinleitorgan transmission gear, which in turn is in engagement with a Drehmomentableitorgan, wherein a locking member, such as a pawl, with a separate at Drehmomenteinleorggan fixed parking lock gear to lock the difference can be brought. In this case, the parking lock gear is designed as a chipless manufactured sheet metal component. The differential is integrated in a drive train of a motor vehicle. Such a drive train is also the subject of the present invention.

In bevel gear differentials, parking locks are usually integrated in a cast housing of the differential. However, such an implementation is not feasible in the case of "lightweight differentials." It is the object of providing a particularly light-weighting, that is, weight-optimized, differential with a parking-gear toothing as cost-effectively as possible.

Disclosure of the invention

This object is achieved in that a provided for contact with rolling elements of the bearing ring on at least one section has a parking lock teeth to come into contact with a pawl. In other words, the ring thus has a running surface for the rolling elements of the rolling bearing. The running surface of the rolling elements is thus in integrated external ring having a ring, wherein the external toothing is designed to come into contact with a pawl in Parkfall / Park state. Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

Thus, it is advantageous if the ring is designed as a bearing outer ring or bearing inner ring of the rolling bearing. As a result, a submodule, comprising bearing elements and parking brake elements, can be used specially adapted to different vehicles in a drive train.

Particularly light / weight-optimized, a differential can be performed when the ring is formed as an integral component of the differential basket, such as a support member. Of course, the support member can also be used as a separate component, i. separated from the differential cage, be formed, whereby the adaptability is increased in terms of different requirements.

It is useful if the ring non-positively and / or positively and / or cohesively with the Differenzialkorb rotationally fixed and / or axially fixed. Sufficient torque transmission can then be ensured.

An advantageous embodiment is also characterized in that a press fit is combined with a positive connection.

The differential then builds particularly compact when the ring is formed as an integral part of a shaft portion or the support member.

If the carrier part is mounted non-rotatably on the bearing ring, assembly is simplified.

The combination of the individual components is simplified if a pin or a bolt transmits torque into the bearing outer ring and the carrier part and the differential cage is introduced. Such a pin or bolt can then be inserted without play in the said three components.

It is also advantageous if a projection extending in the axial direction or a plurality of projections is / are positively inserted into a recess or in recesses of the carrier part.

A further advantageous embodiment is characterized in that the circumferentially as equally distributed projections on an end face of the differential cage are formed as nubs with preferably convex or even circular outer contour, which engage in mutual holes, such as blind holes or through holes of the support member.

The invention not only relates to a lightweight differential designed as a spur gear differential, but may also relate to a lightweight differential made up as a bevel gear differential.

The invention provides a parking lock arrangement in which the toothing is formed on a bearing ring of a roller bearing. The bearing ring is integrally formed a component of a transmission, such as a shaft portion or a preferably carrier part-like component of a differential cage. The parking lock toothing can be produced without cutting, for example. Forming technology, such as deep drawing operations. With the bearing ring a support member of a differential cage is firmly connected, wherein the support member is seated on the bearing ring.

The lightweight differential has an additional flange bearing, the outer ring is produced without cutting drawing. In the tool sequence, the toothing on the outer diameter of the flange is produced by means of an additional punching process. The toothing is not ground again after hardening. Only the bearing track and the seat are rebuilt beitet. There are basically steel alloys. It is an advantage if the non-cutting ring is made of 16MnCr5 or 100Cr6.

Also advantageous are tapered roller bearings with non-cutting produced outer ring. Parklosverzears produced without locking can be incorporated in the outer ring of the bearing.

It is also possible to enter into an additional form-locking connection with the differential housing / differential cage via a connection having an undercut.

The lightweight differential can be provided with a solid bearing and an integrated parking lock toothing. The bearing outer ring of the solid bearing, but possibly also a bearing inner ring of the solid bearing, can be designed as a tapered roller bearing in the present case. It is provided on the bearing outer ring a parking lock teeth. The bearing outer ring is connected not only via a press fit, but in addition via a positive connection with the actual differential case / differential cage. The massive bearing outer ring is manufactured using conventional forging processes.

The teeth are not reworked after a fine forging and calibration process. Only the bearing seat and the bearing track are reworked and sanded accordingly. The parking lock gearing itself can consist of 100Cr6.

While at Kegelraddifferenzialen otherwise usual cast iron housing unfortunately only have a maximum tensile strength in the range of 600 MPa, an improvement is achieved here. The low hardness of the material up to now combined with high hertzian pressure in the parking brake has resulted in a short service life. The integration of the parking brake can also be done at the cone wheel differential on the camp. Since the bearing is usually installed here in X-arrangement, the teeth would have to be housed on the inner ring. This measure would also work well, provided that the interference fit between the inner ring and the housing is carried out so strong that the forces can be transferred from the parking brake. In addition, an additional positive connection could also be realized here.

High-strength bearing steel is advantageous for the ring having the pawl toothing. The lightweight differential can be unobtrusively retrofitted with an additional parking lock teeth / equipped in particular.

The invention will be explained in more detail with the aid of a drawing. In this case, different embodiments are described. Show it:

1 shows a first embodiment of a lightweight differential constructed as a spur gear differential with two tapered roller bearings installed in an O arrangement, wherein the respective outer bearing rings have a parking lock gear,

2 is an enlargement of the area II of FIG. 1,

3 shows one of the roller bearing outer rings in a side view,

4 shows the roller bearing outer ring of FIG. 3 in a perspective view,

5 shows a second exemplary embodiment of a lightweight construction element according to the invention, wherein a materially separated from a differential cage

Carrier part has a tread for rolling elements of a rolling bearing,

6 is an enlargement of the area VI of FIG. 5, 7 shows a third exemplary embodiment in which the differential cage with projections has a form-fitting manner in diametrically opposite recesses of a carrier part having a running surface for the rolling elements of the rolling bearing,

8 is an enlargement of the area VIII of FIG. 7,

Fig. 9 is a side view of the carrier part, as it is used in the embodiments of FIGS. 7 and 8, and

10 is a perspective view of the carrier part of FIG. 9th

The figures are merely schematic in nature and are only for the understanding of the invention. The same elements are provided with the same reference numerals. Such features, which are not shown as essential, are purely optional. The individual features of the individual embodiments can also be interchanged. In Fig. 1, a first embodiment of a lightweight differential 1 according to the invention is shown. The lightweight differential 1 is formed as Stirnraddifferenzi- al 2. It has an input gear 3 in the manner of a spur gear 4. It is torque-transmitting connected to a differential cage / differential housing 5. This differential cage 4 is designed in the manner of a two-part planet carrier 6.

In the planet carrier 6, two sets of planet wheels 8 are rotatably supported by hollow pins 7. The planet gears of the one planetary gear set engage in a torque transmitting manner on a first sun gear 9. The planet wheels of the other planetary gear set engage in a second sun gear 10 to transmit torque. The respective planet gears of one planetary gear set are in meshing engagement with the planet gear of the other planetary gear set. The respective sun gears 9 and 10 are connected to output shafts. This is not shown in the figures. Shown, however, is an internal toothing 1 1, via which a toothing with the output shafts is created. Between the hollow pin 7 and the planet carrier 6, a sleeve 12 is present.

Two rolling bearings 13, which are designed as a tapered bearing, store the differential alkorbus 5. For this purpose, each of the two rolling bearings 13, which are arranged in O arrangement to each other, a bearing outer ring 14 and a bearing inner ring 15. Between the two bearing rings 14 and 15 rolling elements 16, for example in the form of cones 17 are present.

The rolling elements 16 run on an inner running surface 18 of the bearing outer ring 14 and on an outer running surface of the bearing inner ring 15. The bearing outer ring 14 thus provides a contact surface for the rolling elements 16, namely on the inner race 18. The bearing outer ring 14 has at its radially outer periphery a parking lock toothing 20. A ring-like carrier part 21 is pressed between the bearing outer ring 14 and one half of the planet carrier 6. In addition, a bolt 22 is driven through these three components and ensures in all three components via a form and adhesion that rotation in addition to the positive fit between the planet carrier half and the support member 21 and the support member 21 and the bearing outer ring 14 does not take place can. A radially inner end region 23 of the carrier part 21 is so assembled and deep-drawn that, on the one hand, the respective sun gear 9 or 10 is supported radially, but also axially. This can be clearly seen in an enlarged view in Fig. 2. The parking lock toothing 20 is produced without cutting and the carrier part 21 is a deep-drawn part made of sheet metal. In FIGS. 3 and 4, it can be clearly seen that the parking lock toothing 20 is formed in a radially protruding flange region of the bearing outer ring 14. In Fig. 5, a second embodiment is shown, which differs in particular in that the support member 21 forms the bearing outer ring 14. The parking lock toothing 20 is thus formed on a radially projecting flange portion 24. Between the carrier part 21 and the respective half of the planet carrier 6, a press fit is present. This interference fit can serve as the sole torque transmission connection, but it can also be added / inserted form and / or cohesive connection types. In the enlarged view from FIG. 6, it can again be seen that the radially inner end region 23 of the carrier part 21 is dimensioned and positioned for the radial and at the same time axial positioning of the sun gear 9.

FIG. 7 shows a third embodiment of a lightweight differential 1 designed as a spur gear differential 2. They differ in particular in the region of the connection between the carrier part 21 to the respective planet carrier half 6 of the second embodiment.

As can also be clearly seen in FIG. 8, the planetary carrier 6 has an axially extending projection 25 which engages in a hole 26 of the carrier part 21. This creates a positive connection, in particular by using a press fit in this and an adjacent area. The holes 26 are formed as through-holes, as shown in FIG. 9, with 3, 4, 5, 6, 7, 8 or 9 holes distributed around the circumference and extending in the axial direction on the support part 21. They are distributed equally over the circumference. FIGS. 9 and 10 clearly show the uniform distribution of the holes. The two sun gears 9 and 10 may also be referred to as output gears. The peg ring having the peg ring is, for example, conceivable as a bearing outer ring 14 or as a carrier part 21.

LIST OF REFERENCE NUMBERS

1 lightweight differential

2 spur gear differential

3 input gear

4 spur gear

5 differential cage / differential housing

6 planet carriers

7 hollow pins

8 planetary gear

9 first sun wheel

10 second sun wheel

internal gearing

12 sleeve

13 rolling bearings

14 bearing outer ring

15 bearing inner ring

16 rolling elements

17 cones

18 inner tread

19 outer tread

20 parking lock teeth

21 carrier part

22 bolts

23 radially inner end region

24 flange area

25 advantage

26 holes

27 output gear

Claims

claims

1 . Lightweight differential (1) with an input gear (3) provided for the introduction of torque, and two output gears (27) provided for output of torque, the output gears

(27) at least partially within a differential cage (5) are rotatably arranged, wherein at least one rolling bearing (13) for axial and / or radial position determination of the differential cage (5) acts on this, characterized in that a for contact with rolling elements (16) of the rolling bearing (13) provided ring on at least one portion of a parking lock toothing (20).

2. Lightweight differential (1) according to claim 1, characterized in that the ring as a bearing outer ring (14) or bearing inner ring (15) of the rolling bearing (13) is formed.

3. Lightweight differential (1) according to claim 1 or 2, characterized in that the ring is designed as a separate or integral component of the differential cage (5), for example as a carrier part (21).

4. Lightweight differential (1) according to one of claims 1 to 3, characterized in that the ring non-positively and / or positively connected to the differential cage (5) rotationally fixed and / or axially fixed.

5. Lightweight differential (1) according to claim 4, characterized in that a press fit is combined with a positive connection.

6. Lightweight differential (1) according to one of claims 3 to 5, characterized in that the ring is formed as a one-piece part of a shaft lenabschnitt or the support member (21).

7. Lightweight differential (1) according to one of claims 3 to 6, characterized in that the carrier part (21) rotationally fixed on the bearing ring (14, 15) is placed.

8. Lightweight differential (1) according to claim 7, characterized in that a pin or a bolt (22) is introduced to transmit torque in the bearing outer ring (14) and the carrier part (21) and the differential cage (5).

9. Lightweight differential (1) according to one of claims 3 to 8, characterized in that axially extending projections (25) are positively inserted in recesses of the support part (21).

Lightweight differential (1) according to claim 9, characterized in that the equally distributed in the circumferential direction projections (25) on one end face of the differential cage (5) are formed as knobs which engage in opposite holes (26) of the support part (21).