PLANETARY TRANSMISSION WITH DIFFERENTIAL

Abstract

A planetary transmission (1) with a differential (3) and at least one set of planetary gears (6) and with a common planetary carrier (9) for the differential (3) and the set of planetary gears (7) and with at least one set of planet journals (18). The planet journals (7) and first differential gears (11) of the differential (3) are seated so as to follow one another axially on in each case one planet journal (18) and, here, are axially separated from one another by way of the intermediate web (20). The intermediate web (20) which extends in radial directions runs axially between a first toothing plane (I) and a second toothing plane (II).

Claims

1. A planetary transmission, comprising: a differential; at least one set of planetary gears; a common planetary carrier for the differential and the set of planetary gears; at least one set of planet journals; the differential has a set of first differential gears, a set of second differential gears, a first sun gear and a second sun gear, the first differential gears are each in mesh with the first sun gear in a first toothing plane and the second differential gears are each in mesh with the second sun gear in a second toothing plane, and one of the first differential gears is in mesh with at least one of the second differential gears; each of the first and second toothing planes is a radial plane which is perpendicular to a central axis and centrally intersects either respectively the meshing of the first differential gears with the first sun gear or the meshing of the second differential gears with the second sun gear; the planetary carrier comprises a first carrier web, a second carrier web and an intermediate web formed axially between the first and second carrier webs; and in each case one planetary gear of the set of planetary gears and a one of first differential gear of the first set of differential gears is seated to follow one another axially on a planet journal and are axially separated from one another by the intermediate web, and the intermediate web extends in radial directions running axially between the first toothing plane and the second toothing plane.

2. The planetary transmission according to claim 1, wherein planetary gears of a further set of the planetary gears are in mesh with at least one further gear in a third toothing plane, and the third toothing plane is a radial plane extending perpendicular to the central axis and centrally intersecting a meshing of the planetary gears of the further set and the at least one further gear.

3. The planetary transmission according to claim 2, wherein the intermediate web extends axially between the first toothing plane and the third toothing plane.

4. The planetary transmission according to claim 2, wherein the individual toothing planes are axially separated from one another in an axial direction.

5. The planetary transmission according to claim 1, wherein the planet journal is axially supported at one end in the first carrier web, extends axially through the intermediate web to the second carrier web, and is supported at another end in the second carrier web.

6. The planetary transmission according to claim 1, wherein a radial plane centrally intersecting the meshing of the differential gears runs parallel to the toothing planes.

7. The planetary transmission according to claim 6, wherein one of the meshes of the differential gears lies in the radial plane which centrally intersects the meshes of the differential gears and which lies in the first toothing plane.

8. The planetary transmission according to claim 6, wherein one of the meshes of the differential gears lies in the radial plane which centrally intersects the meshes of the differential gears and which extends axially between the first toothing plane and the second toothing plane.

9. The planetary transmission according to claim 1, wherein each of the planetary gears is a first planetary gear of a double planet, and a respective one of the double planets is formed by one of the first planetary gears and a second planetary gear.

10. The planetary transmission according to claim 9, wherein the planet journal has first and second journal steps in a diameter thereof, the first journal step is larger in diameter than the second journal step, and the first differential gears are each seated on the first journal step and each of the double planets is seated on the second journal step.

11. A planetary transmission, comprising: a differential; a set of planetary gears; a common planetary carrier for the differential and the set of planetary gears; a set of planet journals; the differential has a set of first differential gears, a set of second differential gears, a first sun gear and a second sun gear, the first differential gears are each in mesh with the first sun gear in a first toothing plane and the second differential gears are each in mesh with the second sun gear in a second toothing plane, and one of the first differential gears is in mesh with at least one of the second differential gears; the first and second toothing planes are radial planes that extend perpendicular to a central axis and centrally intersect respectively a meshing area of the first differential gears with the first sun gear and a meshing area of the second differential gears with the second sun gear; the planetary carrier comprises a first carrier web, a second carrier web and an intermediate web formed axially between the first and second carrier webs; and one planetary gear of the set of planetary gears and one first differential gear of the set of first differential gears are located on a same one of the planet journals, axially separated from one another by the intermediate web.

12. The planetary transmission according to claim 11, wherein planetary gears of a further set of the planetary gears are in mesh with at least one further gear in a third toothing plane, and the third toothing plane is a radial plane extending perpendicular to the central axis and centrally intersecting a meshing area of the planetary gears of the further set and the at least one further gear.

13. The planetary transmission according to claim 12, wherein the intermediate web extends axially between the first toothing plane and the third toothing plane.

14. The planetary transmission according to claim 12, wherein the first, second, and third toothing planes are axially separated from one another in an axial direction.

15. The planetary transmission according to claim 11, wherein the planet journals are each axially supported at one end in the first carrier web, extend axially through the intermediate web to the second carrier web, and are supported at another end in the second carrier web.

16. The planetary transmission according to claim 11, wherein a radial plane centrally intersecting the meshing area of the differential gears extends parallel to the first and second toothing planes.

17. The planetary transmission according to claim 16, wherein one of the meshing areas of the differential gears lies in the radial plane which centrally intersects the meshing area of the differential gears and which lies in the first toothing plane.

18. The planetary transmission according to claim 16, wherein one of the meshing areas of the differential gears lies in the radial plane which centrally intersects the meshing area of the differential gears and which extends axially between the first toothing plane and the second toothing plane.

19. The planetary transmission according to claim 11, wherein each of the planetary gears is a first planetary gear of a double planet, and a respective one of the double planets is formed by one of the first planetary gears and a second planetary gear.

20. The planetary transmission according to claim 19, wherein the planet journals each have first and second journal steps in a diameter thereof, the first journal step is larger in diameter than the second journal step, and the first differential gears are each seated on the first journal step and each of the double planets is seated on the second journal step.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a longitudinal section view of an embodiment of the planetary transmission;

[0020] FIG. 2 shows another exemplary embodiment of a planetary transmission, the design of which essentially corresponds to that of the planetary transmission shown in FIG. 1; and

[0021] FIG. 3 schematically shows the meshing between a first and second gears.

DETAILED DESCRIPTION

[0022] FIG. 1 shows a planetary transmission 1 in a longitudinal section along the central axis 22 of the planetary transmission 1.

[0023] The planetary transmission 1 consists of a load step 2 and a differential 3. The load step 2 has a third sun gear 4, which is the power input for the planetary transmission 1. The third sun gear 4 is in mesh with planetary gears 7 of double planets 6. In FIG. 1, only one double planet 6 is visible due to the sectional view. Each double planet 6 has a second planetary gear 8 which is connected in a non-rotatable manner to the first planetary gear 7 of the double planet 6 and is rotatably mounted with the latter about the respective journal axis 17 by means of planetary bearings 27 on a planet journal 18. A ring gear 5 is another component of load step 2. The ring gear 5 is in mesh with the second planetary gears 8 of the double planet 6.

[0024] The differential 3 comprises a first set of first differential gears 11 and a second set of second differential gears 16, a first sun gear 12 and a second sun gear 13. Of the set of first differential gears 11, only one differential gear 11 is visible in the illustration of FIG. 1 (above the central axis 22). Another differential gear 11 is hinted at by a dashed line below the central axis 22, because in this view it is hidden by a second differential gear 16 of the second set of differential gears 16. Of the second differential gears 16 of the set of second differential gears 16, only this one is visible. The first sun gear 12 in the image on the left is in mesh with the first differential gears 11 but is not in contact with the second differential gears 16. A radial distance therefore remains between the teeth of the first sun gear 12 and the teeth of the respective second differential gears 16 without coming into contact. The second sun gear 13 is in mesh with the second differential gears 16 but is not in contact with the first differential gears 11 because they cannot come into contact with the second sun gear 13 due to their small axial width. A first differential gear 11 is in mesh with a second differential gear 16. The first differential gears 11 are what are termed the narrow planetary gears of the differential 3. Their axial width is narrower by about half compared to the axial width of the second differential gears 16, which are referred to as wide planetary gears.

[0025] The meshing in the planetary transmission 1 can be divided into 4 toothing planes I to IV. In general, toothing planes are understood to be the position of the meshing of intermeshing gears in the respective imaginary radial plane perpendicularly penetrated by the central axis 22. The imaginary radial planes run perpendicularly into the representation and/or also perpendicularly out of it.

[0026] The toothing planes I and II are assigned to the meshes of the differential gears 11 and 16 respectively. The first toothing plane I is characterized by the meshing of the first sun gear 12 with the first differential gears 11. At the same time, the radial plane R characterized by the meshing of the first differential gears 11 with the second differential gears 16 lies in the same radial plane. The second differential gears 16 are axially wide enough to mesh with the second sun gear 13 in the second toothing plane II. The second toothing plane II is accordingly characterized by the meshing of the second sun gear 13 with the second differential gears 16. The radial plane R, which lies in the toothing plane I, is assigned to the meshing of the differential gears 11 and 16, which are in mesh with one another in pairs, as already mentioned previously. The meshes in the radial plane R are designed with a radial and tangential (to the circumferential direction around the central axis) distance to the meshes of the first sun gear 12 with the first differential gears 11.

[0027] The toothing planes III and IV are assigned to the meshing of the planetary gears of load step 2. The third toothing plane III is characterized by the meshing of the second planetary gears 8 of the double planet 6 with the ring gear 5. The fourth toothing plane IV results from the meshing of the first planetary gears 7 of the double planet 6 with the third sun gear 4.

[0028] The planetary transmission 1 is provided with a planetary carrier 9, which is provided with a carrier web 10 axially on the outer left in the image and with a carrier web 21 on the outer right in the image, as well as an intermediate web 20 according to the disclosure. The intermediate web 20 divides the differential 3 and runs axially between the first toothing plane I and the second toothing plane II.

[0029] The planetary transmission 1 has two sets of planet journals. In the illustration according to FIG. 1, only one planet journal 18 of one of the sets is visible. The planet journal 18 extends axially from the carrier web 10 through the intermediate web 20 to the carrier web 21 and is permanently supported in the carrier webs 10 and 21, and at least under load also in the intermediate web 20, and is fastened there with fastenings 19, for example by flanging, preferably by caulking or stamping.

[0030] The first differential gears 11 are arranged axially between the first carrier web 10 and the intermediate web 20. The second differential gears 12 extend axially through the intermediate web 20 (see the lower end 26 of the intermediate web 20) or alternatively laterally past the intermediate web (not shown) and are mounted at one end in the first carrier web 10 and at the other end in a wall section of the planetary carrier 9 not visible in FIG. 1.

[0031] A first differential gear 11 and a double planet 6 are each seated on a common planet journal 18. The respective differential gear 11 is axially separated from the second planetary gear 8 of the double planet 6 by the intermediate web 20. The double planet 6 is rotatably mounted on the planet journal 18 by means of planetary bearings 27. The differential gears 16 are each mounted on a different planet journal or supported by means of pins in the planetary carrier 9 so that they can rotate about their own planetary axis (not shown in the drawing). The planetary carrier 9 is rotatably mounted by means of rolling bearings 14 and 15 in a housing not shown, for example in a housing of a vehicle axle of an electric vehicle.

[0032] FIG. 2 shows another exemplary embodiment of a planetary transmission 28, the design of which essentially corresponds to that of the planetary transmission 1 shown in FIG. 1. The difference lies in the design of the planet journals 18 and in the position of the radial plane R. The radial plane R with the tooth contacts of the differential gears 11 and 16 runs axially between the toothing planes I and II. The differential gears 16 are not visible due to the partial section shown in FIG. 2.

[0033] While the planet journals 18 in the differential 3 have the same diameter throughout, the planet journals 30 in the planetary transmission 28 are designed to have two steps with regard to the diameter. The first journal step 24 arranged in the differential 29 is larger in diameter than the second journal step 23 in load step 2. The inner diameter of the through hole in the intermediate web 20 corresponds in nominal dimension to the diameter of the second journal step 23. Since the diameter of the first journal step 24 is larger than that of the second journal step 23, the first journal step 24 will not fit axially through the through hole in the intermediate web 20 and will strike axially against the intermediate web 20. A fastening 19 of the planet journal 30 is optionally only necessary as shown on the right side of the second carrier web 21. Alternatively, only one fastening of the planet journal 30 to the first carrier web 10 can be provided (not shown). The planet journal 30 can be mounted in the carrier web 10 in an axially floating manner without the fastening or can only be pressed in. The same applies alternatively to a floating mounting of the planet journal 30 in the second carrier web 21.

[0034] FIG. 3 schematically shows the meshing between a first gear 31 and a second gear 32. The illustration generally serves to describe the position of a toothing plane V in the meshing of the gears 31 and 32. The two gears 31 and 32 are in mesh with one another via their helical toothing 34 and 35. The flank lines of the helical toothing 34 run curved in space and are marked with the reference numeral 39 in their projection into the image plane in FIG. 3. The imaginary extension of this projection 39 and the gear axis 35 of the first gear enclose a helix angle alpha of the helical toothing 34 or 35 between them. The center 37 of the meshing of both gears 31 and 32 lies in the toothing plane V. In the ideal case under consideration, the center 37 lies at half the width B/2 of the tooth width B or gears 31 and 32. It is therefore assumed that the tooth contact moves along the flank lines over the entire width B of the gears 31 and 32.

TABLE-US-00001 Reference Symbols 1 Planetary transmission 2 Load step 3 Differential 4 Third sun gear 5 Further gear, ring gear 6 Double planet 7 First planetary gear of the double planet 8 Second planetary gear of the double planet 9 Planetary carrier 10 Carrier web 11 First differential gear of the differential 12 First sun gear 13 Second sun gear 14 Rolling bearing 15 Rolling bearing 16 Second differential gear of the differential 17 Journal axis 18 Planet journal 19 Fastening 20 Intermediate web 21 Carrier web 22 Central axis of the differential or planetary transmission 23 Second journal step 24 First journal step 25 Fastening 26 Lower end of the intermediate web 27 Planetary bearing 28 Planetary transmission 29 Differential 30 Planet journal 31 First gear 32 Second gear 33 Helical toothing of the first gear 34 Helical toothing of the second gear 35 Gear axis of the first gear 36 Gear axis of the second gear 37 Center 38 Imaginary extension of the flank line 39 Projection of the flank line I First toothing plane II Second toothing plane III Third toothing plane IV Fourth toothing plane alph Helix angle B Width of the gear B/2 Half of the width of the gear R Radial plane V Toothing plane