WO2021000988A1

WO2021000988A1 - Drive unit having coolant guidance system for supplying and distributing a fluid flow between two gearbox input shafts

Info

Publication number: WO2021000988A1
Application number: PCT/DE2020/100465
Authority: WO
Inventors: Oliver Nöhl
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2019-07-04
Filing date: 2020-06-04
Publication date: 2021-01-07
Also published as: CN113939667A; KR20220029583A; DE102019118079A1; DE102019118079B4; EP3994369A1

Abstract

The invention relates to a drive unit (1) for a motor vehicle drivetrain, having a double clutch (2), two gearbox input shafts (4, 5), which are arranged coaxially relative to each other and mounted rotatably relative to each other via a rolling bearing (3), wherein a first partial clutch (6a) of the double clutch (2) is operatively connected to a first gearbox input shaft (4) and a second partial clutch (6b) of the double clutch (2) is operatively connected to a second gearbox input shaft (5), which is slid onto the first gearbox input shaft (4) radially from the outside, and having a coolant guidance system (8), which is implemented in part by a radial gap (7) reserved radially between the two gearbox input shafts (4, 5). The coolant guidance system (8) is designed such that a first partial flow (9a), which leads axially to the rolling bearing (3), and a second partial flow (9b), which is axially opposed to the first partial flow (9a) and is larger than the first partial flow (9a), are generated during operation. The two gearbox input shafts (4, 5) and the rolling bearing (3) are designed such that a fluid flow (11) flowing radially inward through an input opening (10) of the second gearbox input shaft (5) is divided into the first and second partial flow (9a, 9b) during operation within the radial gap (7).

Description

Drive unit with coolant control system for supplying and dividing a fluid flow between two transmission input shafts

The invention relates to a drive unit for a motor vehicle drive train, d. H. a drive train of a motor vehicle, such as a car, truck, bus or other commercial vehicle, with a double clutch, two coaxially arranged transmission input shafts rotatably mounted relative to each other via a roller bearing, a first partial clutch of the double clutch being operatively connected to a first transmission input shaft and a second partial clutch of the double clutch is operatively connected to a second transmission input shaft arranged radially outside the first transmission input shaft, as well as to a coolant control system which is partially implemented by a radial gap between the two transmission input shafts, the coolant control system being designed such that a first partial flow, which leads axially to the roller bearing, and a second partial flow, which axially opposes the first partial flow and is larger than the first partial flow, are generated.

Prior art of the generic type is known from CN 104061319 B, for example. The division of different partial flows takes place through two axially spaced through bores in the second transmission input shaft and through a separate seal between the transmission input shafts.

A disadvantage of the designs known from this prior art is, however, that an additional / relatively high drag torque acts on the driven transmission input shaft between the two transmission input shafts for dividing the partial flows. In addition, the manufacture and assembly of one of the two transmission input shafts are relatively complex.

It is therefore the object of the present invention to remedy the disadvantages known from the prior art and to provide a drive unit provided with a coolant control system, which is further improved in terms of its efficiency and has lower assembly and manufacturing costs. This is achieved according to the invention in that the two transmission input shafts and the roller bearing are designed (and coordinated with one another) in such a way that a division of a fluid flow flowing radially inward through an input opening of the second transmission input shaft during operation into the first and the second partial flow within the radial gap he follows.

With this design of the coolant control system, two axially spaced apart input openings in the transmission input shaft are no longer required. The number of holes to be implemented and consequently the manufacturing effort are reduced as a result. Furthermore, the number of seals used is reduced because it is no longer necessary to seal the partial flows within the radial gap, between the two transmission input shafts, which are split up before penetrating the second transmission input shaft. This also reduces the manufacturing effort. The assembly effort is also made easier because the seal does not have to be applied and pushed in.

Further advantageous embodiments are claimed with the subclaims and explained in more detail below.

Accordingly, it is also advantageous if the two transmission input shafts are axially spaced apart radially from one another, extending from the roller bearing to a free axial end of the second transmission input shaft. The radial gap formed between the Wälzla ger and the free end of the second transmission input shaft is thus implemented axially continuously. The existing drag torque is thereby further reduced.

In addition, it is useful if a first section of the radial gap located axially between the inlet opening and the roller bearing has a smaller (minima len) flow cross-section than a second sub-section of the radial gap located axially between the inlet opening and the free axial end of the second transmission input shaft. This cleverly divides the two partial flows. It is also advantageous if at least one radial shoulder that narrows the first partial section is formed on the first transmission input shaft and / or on the second transmission input shaft. This radial shoulder is particularly preferably implemented on the radial outside of the first transmission input shaft. This further reduces the manufacturing effort.

In this regard, it is also expedient if a first radial shoulder is formed / arranged towards an (axial) end of the first partial section facing the inlet opening. This first radial shoulder is further preferably implemented (with the implementation of a gap seal) directly by a radial shoulder.

In addition, it is advantageous if a second radial shoulder (in addition to or as an alternative to the first radial shoulder) is formed / arranged at an (axial) end of the first section facing the roller bearing. The second radial shoulder is also preferably implemented as a radial shoulder. As a result, the corresponding flow cross-section is again skillfully set.

Furthermore, it is expedient if a slave cylinder of a hydraulic actuating device which interacts with at least one of the partial clutches is supported radially from the outside on the second transmission input shaft. This makes the drive unit particularly compact.

If, in addition, a cylinder housing of the slave cylinder forms a supply channel of the coolant control system leading to the inlet opening, the coolant control system is still particularly cleverly integrated into the already existing components of the drive unit.

Accordingly, it is also advantageous if two seals are arranged axially adjacent to the input opening radially between the slave cylinder and the second transmission input shaft. A first seal is preferably arranged to a first axial side of the inlet opening, while a second seal to one of the first axial side facing away from the second axial side of the inlet opening is arranged towards.

In other words, according to the invention, a supply and distribution of a cooling oil between the transmission input shafts is realized. It is proposed to make the distribution of the cooling oil volume storm in the gap between the transmission input shafts. This eliminates the previous division across different total cross-sectional areas of different bores.

The invention will now be explained in more detail below with reference to figures, in which context different exemplary embodiments are also illustrated.

Show it:

Fig. 1 is a longitudinal sectional view of a drive unit according to the invention according to a first embodiment, in which the entire structure of the drive unit can be clearly seen,

FIG. 2 shows a detailed longitudinal sectional view of the drive unit of FIG. 1 in an area of a radiator gap designed to split a fluid flow between two existing transmission input shafts, and FIG

Fig. 3 is a detailed longitudinal sectional view of a drive unit according to the invention according to a second embodiment in the area as it was already selected in Fig. 2, wherein the radial gap is implemented in a slightly different way compared to the first embodiment.

The figures are only of a schematic nature and are used exclusively for understanding the invention. The same elements are provided with the same reference numerals.

In Fig. 1, a drive unit 1 according to the invention is shown according to a preferred first embodiment. The drive unit 1 is typically in one Drive train of a motor vehicle and thus used in operation in the direction of torque transmission between an internal combustion engine and a transmission.

The drive unit 1 is provided with a double clutch 2. The double clutch 2 is inserted between an input / input shaft 23 of the drive unit 1 and two transmission input shafts 4, 5. A first partial clutch 6a of the double clutch 2 is used between the input shaft 23 and a first transmission input shaft 4 of a transmission, not shown here for the sake of clarity, and a second partial clutch 6b of the double clutch 2 is effective between the input shaft 23 and a second transmission input shaft 5 used. The transmission input shafts 4, 5 are arranged coaxially to one another and consequently have a common axis of rotation 26 about which they can be driven. The directions used axially, radially and in the circumferential direction relate to this axis of rotation 26, so that with axial a direction along / parallel to the axis of rotation 26, with radial a direction normal to the axis of rotation 26 and with the circumferential direction a direction tangential to one about the axis of rotation 26 coaxial circular line is meant ge.

The respective partial clutch 6a, 6b is implemented as a friction disk clutch and is actuated via a hydraulic actuating device 19. The hydraulic actuator 19 has a slave cylinder 18. This slave cylinder 18 is implemented as a concentric slave cylinder 18. The slave cylinder 18 has two sub-units, each sub-unit having an actuating effect on one of the two sub-clutches 6a, 6b via its corresponding piston.

The respective partial clutch 6a, 6b has a friction disk set 24a, 24b due to its design as a friction disk clutch. The first partial clutch 6a is arranged with its (first) friction plate set 24a radially outside of a (second) friction plate set 24b of the second partial clutch 6b. A coolant control system 8 is provided to cool different constituent parts of the drive unit 1, in particular the friction disk packs 24a, 24b and a (first) roller bearing 3 inserted between the two transmission input shafts 4, 5. The coolant control system 8 is partially formed in a cylinder housing 20 of the slave cylinder 18. In Fig. 1, a part of a feed channel 21 can be seen radially between the cylinder housing 20 and the second transmission input shaft 5. This zuleitkanal 21 opens on its radial inside directly into an inlet opening 10 of the coolant control system 8. The inlet opening 10 is implemented here by a radial through hole in the second transmission input shaft 5 designed as a hollow shaft. In practice, there are typically a plurality of inlet openings 10 which are distributed in the circumferential direction and which are connected to the feed channel 21 which is set as an annular gap.

The supply channel 21 is sealed on a first axial side of the inlet opening 10 with a first seal 22a and on a second axial side of the inlet opening 10 opposite the first axial side with a second seal 22b, which seals 22a, 22b between the cylinder housing 20 and the second transmission input shaft 5 are arranged.

As can be seen in detail from FIG. 2, a radial gap 7 of the coolant control system 8 directly adjoins the inlet opening 10 radially inside the inlet opening 10. The radial gap 7 is that gap which is located radially between the first transmission input shaft 4 formed as a solid shaft and the second transmission input shaft 5 arranged radially outside the first transmission input shaft 4 and designed as a hollow shaft. The two transmission input shafts 4, 5 are, as already mentioned, arranged coaxially to one another, the second transmission input shaft 5 with its hollow section being pushed onto the first transmission input shaft 4 from the outside. The first roller bearing 3, which here is a needle bearing, is used to support the two transmission input shafts 4, 5 relative to one another.

In this context, it can also be seen from FIG. 1 that the first transmission input shaft 4 also accommodates a further second roller bearing 25. The second roller bearing 25, which serves to support the input shaft 23 relative to the first transmission input shaft 4, is arranged on the first transmission shaft 4 on an axial side facing the input shaft 23. The second roller bearing 25 is also implemented here as a needle bearing. The radial gap 7, as again shown in Fig. 2, is divided into two sections 13, 14 un. The two subsections 13, 14 run from the inlet opening 10 in mutually opposite axial directions. Accordingly, a first section 13 of the radial gap 7 is implemented axially between the inlet opening 10 and the first Wälzla ger 3. A second section 14, which connects to the first section 13, is implemented axially between the input opening 10 and a (free) end 12 of the second transmission input shaft 5. The second section 14 extends beyond the free end 12 and occurs from there radially outward in corresponding areas of the partial couplings 6a, 6b. The free end 12 typically protrudes axially so far towards the friction plate packs 24a, 24b that, during operation, the centrifugal force effect that occurs, the fluid conveyed through the second section 14 of the radial gap 7 automatically radially outwards from the second section 14 becomes.

According to the invention, the two transmission input shafts 4, 5 and the roller bearing 3 are designed and coordinated with one another in such a way that a division of a fluid flow 11, which flows radially inwardly through the input opening 10 of the second transmission input shaft 5 during operation, into the first and second partial flows 9a, 9b directly within of the radial gap 7 takes place. For this purpose, the two subsections 13, 14 are specifically implemented with different flow cross-sections. A (minimal) first flow cross section of the first subsection 13 is smaller than a (minimal) second flow cross section of the second subsection 14.

In the first exemplary embodiment, the first transmission input shaft 4 has, on its radial outer side, a first set 15 which forms a radial shoulder. This first shoulder 15 tapers the radial gap 7 / the cross section of the radial gap 7 in such a way that a type of gap seal is formed radially between the transmission input shafts 4, 5. The first shoulder 15 is arranged at a first axial end 17 a of the first partial section 13 facing the inlet opening 10. Furthermore, it can be seen from FIG. 2 that a further second shoulder 16 is present at a second axial end 17b of the first partial section 13 which is axially opposite the first end 17a. This second paragraph 16 is also called radial Shoulder realized and tapered in turn the radial gap 7 / the cross section of the Ra dialspalts 7. The second paragraph 16 directly forms an axial stop surface for the first roller bearing 3. By targeted provision of the two paragraphs 15, 16 on the first transmission input shaft 4, it comes in the first embodiment for setting the flow cross-section and for dividing the amount conveyed by the fluid flow 11 into the first partial flow 9a (through the first partial section 13) and the second partial flow 9b (through the second partial section 14).

In this context, in connection with FIG. 3, it should be pointed out that the setting of the flow cross section and the division of the partial flows 9a, 9b can also take place in a different manner. Accordingly, the first paragraph 15 can also be designed to be smaller than the second paragraph 16 or even be omitted in other embodiments. Furthermore, in further embodiments, the first roller bearing 3 can be held as a flow barrier and even both paragraphs 15, 16 can be omitted.

In other words, one idea of the invention is that the distribution of the cooling oil volume flow to supply the clutch (second partial flow 9b) and to supply the bearings 3 (first partial flow 9a) between the transmission input shafts 4, 5 in the gap 7 between the second transmission input shaft 5 and the first Ge transmission input shaft 4 takes place. This eliminates the previous division over different total cross-sectional areas of the bores in the second transmission input shaft 5.

As an example, a current division has been made as follows: Supply to clutch 2 (via second partial flow 9b): 6 x 06 mm; Supply of bearings 3 (via the first part of current 9a): 1 x 02.5; ie the flow resistance differs approximately by the factor 200 and thus approx. 0.075 l / min arrive at bearing 3 from 15 l / min total volume flow 11. The distribution of the volume flow 11 for the bearing 3 (via the first part of the current 9a) can be done via: 1. Locking effect via the bearing 3 due to small passage cross-sections and / or speed difference between the first transmission input shaft 4 and the second transmission input shaft 5 one narrow radial gap 7 (through second paragraph 16) between the first transmission input shaft 4 and the second transmission input shaft 5 (gap seal) close to the bearing 3. The gap should roughly be approx. 5 mm long (axial extension) and an outer diameter of 25, 5 mm and an inside diameter of 25.06 mm, so that approx. 0.075 l / min flow to bearing 3. 3. Locking effect via a narrow radial gap 7 (through first paragraph 15) between the first transmission input shaft 4 and the second transmission input shaft 5 (gap seal) close to the feed bores 10. In addition, the total cooling oil volume flow is directed to the second transmission input shaft 5 via the CSC housing 20 and sealed to the second transmission input shaft 5 by means of two seals 22a, 22b.

Reference list

Drive unit

Double coupling

first roller bearing

first transmission input shaft

second transmission input shaft

a first partial coupling

b second partial coupling

Radial gap

Coolant control system

a first substream

b second partial flow

0 entrance opening

1 fluid flow

2 free end

3 first section

4 second section

5 first paragraph

6 second paragraph

7a first end

7b second end

8 slave cylinders

9 actuating device

0 cylinder housing

1 supply channel

2a first seal

2b second seal

3 input shaft

4a first friction plate pack

4b second friction plate pack

5 second roller bearing

Claims

1. Drive unit (1) for a motor vehicle drive train, with a double clutch (2), two coaxially arranged transmission input shafts (4, 5) which are rotatably mounted relative to one another via a roller bearing (3), a first partial clutch (6a) of the double clutch ( 2) is operatively connected to a first transmission input shaft (4) and a second partial clutch (6b) of the double clutch (2) is operatively connected to a second transmission input shaft (5) arranged radially outside the first transmission input shaft (4), as well as to ei nem partially implemented by a radial gap (7) provided radially between the two transmission input shafts (4, 5), the coolant control system (8) being designed in such a way that, during operation, a first partial flow (9a) which is axially connected to the Rolling bearing (3) leads out, and a second partial flow (9b), which is axially opposite to the first partial flow (9a) and is larger than the first partial flow (9a), are generated thereby indicates that the two transmission input shafts (4, 5) and the roller bearing (3) are designed such that a division of an input opening (10) of the second transmission input shaft (5) during operation radially inwardly flowing through fluid flow (11) in the first and second partial flow (9a, 9b) takes place within the radial gap (7).

2. Drive unit (1) according to claim 1, characterized in that the two transmission input shafts (4, 5) axially continuously from the roller bearing (3) to a free axial end (12) of the second transmission input shaft (5) towards ra dial from each other are spaced.

3. Drive unit (1) according to claim 1 or 2, characterized in that an axially between the inlet opening (10) and the roller bearing (3) located first subsection (13) of the radial gap (7) has a smaller flow cross-section than an axially between the input opening (10) and the free axial end (12) of the second transmission input shaft (5) located second part section (14) of the radial gap (7).

4. Drive unit (1) according to claim 3, characterized in that on the first transmission input shaft (4) and / or on the second transmission input shaft (5) at least one the first section (13) narrowing radial offset (15, 16) is formed is.

5. Drive unit (1) according to claim 4, characterized in that a first radial shoulder (15) is formed on one of the inlet opening (10) facing end (17a) of the first section (13).

6. Drive unit (1) according to claim 4 or 5, characterized in that a second radial shoulder (16) is formed on an end (17b) of the first section (13) facing the roller bearing (3).

7. Drive unit (1) according to one of claims 1 to 6, characterized in that on the second transmission input shaft (5) radially from the outside a slave cylinder (18) with at least one of the partial clutches (6a, 6b) cooperating hydraulic actuating device ( 19) is supported.

8. Drive unit (1) according to claim 7, characterized in that a cylinder housing (20) of the slave cylinder (18) forms a feed channel (21) of the coolant control system (8) leading to the inlet opening (10).

9. Drive unit (1) according to claim 7 or 8, characterized in that axially adjacent to the input opening (10) two seals (22a, 22b) are arranged radially between the slave cylinder (18) and the second transmission input shaft (5).