WO2008064871A1

WO2008064871A1 - Automatic planetary transmission

Info

Publication number: WO2008064871A1
Application number: PCT/EP2007/010305
Authority: WO
Inventors: Thomas Listner
Original assignee: Daimler Ag
Priority date: 2006-12-01
Filing date: 2007-11-28
Publication date: 2008-06-05
Also published as: DE102006056753A1

Abstract

The invention relates to an automatic planetary transmission having only five shift elements (K1, K2, K3, B1, B2). Said transmission (K1, K2, K3, B1, B2) has a structurally simple design since the shift elements (K1, K2, K3, B1, B2) are arranged upstream and downstream of the planetary gear sets (4, 5, 6). Here, it is possible for an electric motor to be provided, so as to generate an automatic planetary transmission with a hybrid function and CVT mode.

Description

planetary automatic transmission

The invention relates according to the one-part claim 1 a planetary gear.

From DE 101 62 880 Al a planetary gear is already known, which has six switching elements in addition to three planetary gear sets. It is undifferentiated mentions that on each shaft an electric machine can be attached as a generator or as a prime mover, which is provided in addition to the six switching elements. Disadvantageously, four switching elements are open in each of the seven possible forward gears and the two reverse gears, resulting in high drag losses.

The object of the invention is to provide a low-cost hybridizable planetary automatic transmission with good efficiency.

This object is achieved with the features of claim 1.

According to an advantage of the invention, only five switching elements are provided. In addition, an electric motor can be designed as a generator and Drive machine is operable. Thus, hybrid vehicle transmissions and purely internal combustion engine driven six-speed automatic planetary gear can be manufactured with a very large component equality. Here, according to the invention, a concrete wheel set with three planetary gear sets is specified. With this wheel set, six forward gears, one reverse gear and gear ratios of 6.0 to 8.0 can be achieved without the speed factors - and thus the speeds - on the rotating components of the planetary gear in one of the gears are too high.

As a result, the planetary automatic transmission is hybridizable. For this purpose, it is particularly advantageous to couple the rotor of the electric motor at the given wheelset with the planet carrier of the rear planetary gear set. The stator of the electric motor is fixed to the housing. This arrangement allows even in a particularly advantageous manner, a CVT mode of the planetary gear, in which the planetary gear in a certain driving range allows a stepless ratio change, with part of the drive power is either output from an energy storage or cached in the energy storage. Such an energy store may in particular be a battery, a capacitor or a fuel cell.

In a particularly advantageous manner, the planetary automatic transmission according to the invention in the aisles basically only three switching elements are open, which compared to the four open switching elements according to DE 101 62 880 Al means lower drag losses. Such drag losses are particularly negative for carrying when the switching elements are designed with multi-plate clutches. But conical friction clutches have such drag losses. In this case, the five switching elements can be arranged in a particularly advantageous manner in front of and behind the three planetary gear sets. In particular, three switching elements can be arranged in front of the three planetary gear sets, whereas two switching elements are arranged behind the three planetary gear sets. Since thus no switching elements between the planetary gear sets are available, a particularly compact and lightweight construction of the planetary gear is possible. It is also easy in this case to integrate the electric motor for the hybrid drive in the transmission.

Further advantages of the invention will become apparent from the other claims, the description and the drawings.

The invention is explained below with reference to several embodiments.

Showing:

1 is a planetary gear,

FIG. 2 is a table showing, on the one hand, the shift pattern of the planetary automatic transmission of FIG. 1 and, on the other hand, the gear ratios and increments of a specific transmission design, FIG.

Fig. 3 is a table with the speed factors n, which at the rotating components of the

Planetary automatic transmission according to FIG. 1 can be achieved if this is carried out with the already mentioned for Fig. 2 concrete transmission design,

Fig. 4 in a table relative speeds at

Switching elements of the planetary automatic transmission according to FIG. 1, Fig. 5 for three alternative total spreads of

Planetary automatic transmission according to FIG. 1 associated with the six possible forward gears

Translations Fig. 6 for these three alternative total spreads according to

Fig. 5, the spreads over the associated

Gear steps, Fig. 7 shows the power flow of the planetary gear according to

Fig. 1 in the first forward gear, Fig. 8, the power flow of the planetary gear according to

Fig. 1 in the second forward gear, Fig. 9, the power flow of the planetary gear according to

Fig. 1 in the third forward gear, Fig. 10, the power flow of the planetary gear according to

Fig. 1 in the fourth forward gear, Fig. 11, the power flow of the planetary gear according to

Fig. 1 in the fifth forward gear, Fig. 12, the power flow of the planetary gear according to

Fig. 1 in the sixth forward gear and Fig. 13 in a drawing a plurality of variations

Planetary automatic transmission, which as

Hybrid transmission is executed.

1 shows a planetary automatic transmission with a transmission input shaft 1 and a transmission output shaft 2, which are arranged in a housing 3. The transmission input shaft 1 is coupled by means of a starting element 20 and optionally a torsional vibration damper with an internal combustion engine, not shown. The starting element 20 may in particular be a hydrodynamic torque converter, a hydrodynamic clutch or a wet or dry starting clutch. There are three successively arranged without interposition of a switching element planetary gear sets 4, 5, 6 are provided.

The switching elements are arranged before and after the planetary gear sets 4, 5, 6 and comprise two brakes Bl, B2 and three clutches Kl, K2 K3, so that a total of five switching elements are provided. By means of these five switching elements, a selective switching of six forward gears Vl to V6 and a reverse gear Rl can be realized. The planetary gearbox has in addition to the transmission input shaft 1 and the transmission output shaft 2, five further rotatable shafts, which

a front hollow shaft 7,

a rear hollow shaft 9,

a first middle hollow shaft 10,

- A second middle hollow shaft 11 and

- Include a third middle hollow shaft 12.

The drive can be done via the front hollow shaft 7, which is rotatably connected to the sun gear 13 of the first planetary gear set 4, so that the output can be done via the transmission output shaft 2, which is connected to the planet carrier 14 of the second planetary gear set 5, wherein planet gears 25 on this planet carrier 14 are rotatably arranged. The rear hollow shaft 9 is rotatably connected to the sun gear 15 of the second planetary gear set 5 and the sun gear 16 of the third planetary gear set 6. The second central hollow shaft 11 constantly connects the planet carrier 17 of the first planetary gearset 4 in a rotationally fixed manner to the ring gear 18 of the third planetary gearset 6. Planetary gears 23 of the forwardmost planetary gearset 4 are rotatably mounted on this planet carrier 17. The third middle hollow shaft 12 is front rotatably connected to the ring gear 22 of the first planetary gear set 4. The first middle hollow shaft 10 connects the planet carrier 19 of the third planetary gear set 6 with the ring gear 20 of the second planetary gear set 5, wherein on the planet carrier 19 planet gears 24 are rotatably arranged.

The rear hollow shaft 9 is frictionally connected by means of the brake B2 and rotatably connected to the housing 3. The third middle hollow shaft 12, however, by means of the brake Bl frictionally and rotatably connected to the housing 3 can be connected. This is also the non-rotatably coupled to the third middle hollow shaft 12 ring gear 22 of the frontmost planetary gear set 4 with the brake Bl relative to the housing 3 can be fixed. By means of the clutch K2, the front hollow shaft 7 with the first central hollow shaft 10 frictionally and rotatably connected. The third middle hollow shaft 12 and the first middle hollow shaft 10 are frictionally connected by means of the clutch K3 and rotationally fixed.

The shaft 13 and the shaft 17 are frictionally coupled with each other by means of the clutch Kl.

2, a circuit diagram of the planetary automatic transmission is shown. This shift pattern can also be taken as an example from the respective ratios i of the individual gear stages and the incremental steps φ to be determined therefrom and the total spread φ _{λ / 6} .

Furthermore, it can be seen from the circuit diagram that double circuits are avoided in the case of a sequential shift, since in the case of two adjacent gear stages, one common shift element is engaged in each case. In addition, the circuit diagram of FIG. 2 can be seen that in any circuit between the first forward gear Vl and the fourth forward gear V4 and

- Between the fourth forward gear V4 and the sixth forward gear V6 only one switching element must be additionally engaged. Another advantage is that so-called double high and double reverse can be performed from each forward speed. They allow switching, for example, from the first forward gear Vl to the third forward gear V3 by means of skipping the second forward gear V2, wherein the shifting sequence can be carried out identically to a single gearshift. Only one switching element has to be additionally indented.

In switching operations between the first forward gear Vl and the fourth forward gear V4 thus the brake B2 is engaged in each case, wherein the brake B1 in the first forward gear, the clutch K3 in the second forward gear V2, the clutch Kl in the third forward gear V3, and the fourth forward gear V4 Clutch K2 is additionally engaged.

In switching operations between the fourth forward gear V4 and the sixth forward gear V6, the clutch K2 is engaged in each case and in addition, the clutch Kl is engaged in the fifth forward gear V5 in the sixth forward gear V6, the brake Bl.

In the first reverse gear, the clutch K3 and the brake Bl are engaged.

FIGS. 7 to 12 show the power flows for the six forward gears V 1 to V 6. The power flow is shown as a hatched line. In the following, a concrete interpretation of the three planetary gear sets 4, 5, 6 is shown.

In this case, the front-most planetary gear set 4 on the ring gear 22 has one hundred teeth. By contrast, its sun gear has sixty-four teeth. The associated planet gears 23 each have eighteen teeth.

The middle planetary gear set 5 has ninety teeth on the ring gear 20. By contrast, its sun gear 15 has thirty-four teeth. The associated planet gears 25 each have twenty-seven teeth.

The rear planetary gear set 6 has seventy-one teeth on the ring gear 18. By contrast, its sun gear 16 has thirty-three teeth. The associated planet gears 24 each have nineteen teeth.

With this design, the values for the individual forward gears V1 to V7 shown in FIG

Translations i, the increments φ and the total spread φi _/ 6 reached.

The table according to FIG. 3 shows the rotational speed factors n, which are achieved at the rotating components of the planetary automatic transmission, if it is designed with the concrete number of teeth shown above. The six forward gears Vl to V6 and the reverse gear Rl are shown in the rows of the table. On the other hand, in the columns, the rotational speed factors n are successive:

the ring gear 22 of the front planetary gear set 4,

the planet carrier 17 of the front planetary gear set 4,

- Sonnerads 13 of the front planetary gear set 4, the ring gear 18 of the rear planetary gear set 6,

the planetary carrier 19 of the rear planetary gearset 6 or of the ring gear 20 of the middle planetary gearset 5 that is non-rotatably coupled to this planet carrier 19,

the Sonnerads 16 of the rear planetary gear set 6,

- The transmission output shaft 2 and

- Sonnerads 15 of the central planetary gear set 5, for rotation about a central axis 30 of the

Planetary automatic transmission shown. Subsequently, in the columns, the rotational speed factors n are consecutive:

the planet gears 23 of the front planetary gear set 4,

- The planet gears 25 of the rear planetary gear set 5 and

- The planet gears 24 of the central planetary gear set 6 for rotation about their own axis of rotation 31 and 32 and 33, respectively. It can be seen that the speed factors n have acceptable values. Thus, the highest speed factors occur in the sixth forward gear V6 and are only at 2.312.

Fig. 4 shows in a table, the relative speeds n _re i to the switching elements. The six forward gears Vl to V6 and the reverse gear Rl are shown in the rows of the table. In contrast, the relative speeds are shown in columns n _rel at clutches Kl to K3 and the brakes Bl and B2 illustrated. It can be seen here that the relative speeds have n _rel on the switching elements acceptable values so that the losses are kept low.

Fig. 5 shows three alternative total spreads φ _{x / 6,} each of the six possible forward gears Vl to V6 associated translations i. It represents the middle Total spreads φi _{/ 6 represent} the previously described planetary automatic transmission. These three alternative total spreads are approximately φi _{/ 6} = 7.0, φi _{/ 6} = 8.1 and ψi _{/ 6} = 6.1. In FIG. 6, the spreads over the associated gear jumps V1 → V2, V2 → V3, V3 → V4, V4 → V5, V5 → V6 are shown for these three alternative total spreads φ _1/6 .

Fig. 13 shows in a drawing several alternative embodiments of a planetary gear, which is designed as a hybrid transmission. In this case, an electric motor is provided with respect to Fig. 1, which is illustrated by five possible installation locations of the electric motors El to E5. The remaining components are unchanged from the planetary automatic transmission according to FIG. 1, so that the components provided with the same reference numerals are only partially discussed.

The electric motor comprises a stator 100a or 100b or 100c or 10Od or 10Oe and a rotor 101a or 101b or 101c or 101d or 101e. Each of these rotors can be coupled by means of a clutch KHyI or KHy2 or KHy3 or KHy4 or KHy5 to a transmission element of the planetary automatic transmission.

In the first hybrid transmission, the rotor 101a of the electric motor El by means of the coupling KHyI with the hollow shaft 9 rotatably coupled.

In the second hybrid transmission, the rotor 101b of the electric motor E2 can be coupled in a rotationally fixed manner to the planet carrier 19 by means of the clutch KHy2. In the third hybrid transmission, the rotor 101c of the electric motor E3 can be coupled in a rotationally fixed manner to the third middle hollow shaft 12 by means of the coupling KHy3.

In the fourth hybrid transmission, the rotor 101d of the electric motor E4 can be coupled in a rotationally fixed manner to the frontmost planet carrier 17 by means of the clutch KHy4.

In the fifth hybrid transmission, the rotor 101e of the electric motor E5 can be coupled in a rotationally fixed manner to the transmission input shaft 1 by means of the clutch KHy5.

The stator 100a or 100b or 100c or 10Od or 10Oe, however, is rotatably connected to the housing 3. In the coupling KHyI or KHy2 or KHy3 or KHy4 or KHy5 may be provided in alternative embodiments, a torsionally elastic torsion damper, which allows a certain rotational play.

In the first hybrid transmission starting the engine with the electric motor El is not possible. For example, a conventional starter motor may be provided. A purely electric drive - ie without an internal combustion engine - is possible. A boost operation in which the drive power is boosted by means of the internal combustion engine is not possible. A recuperation is limited. The electric motor El makes it possible to operate the hybrid transmission in the so-called CVT mode. Both electric power can be introduced into the electric motor El in internal combustion engine operation, and electrical power can also be taken. As a result, the torque output at the transmission output shaft 2 can also be varied, which in turn has a retroactive effect on its rotational speed and thus the vehicle speed. Due to the wide band of maximum dischargeable power and maximum removable power lets the transmission continuously adjusted in a set by means of the switching elements gear over a wide band.

In the second hybrid transmission starting of the internal combustion engine with the electric motor E2 is possible. There is no need for a starter motor. The clutches KHy2 and K2 are engaged and thus the electric motor E2 drives the engine 1: 1.

A purely electric ride - i. without combustion engine - is possible. In a first electric driving range, the clutches KHy2, K2 and K3 are engaged and thus the electric motor E2 drives the transmission output shaft 2 1: 1. In a second electric driving range, the clutches KHy2, B3 are engaged and thus the electric motor E2 drives the transmission output shaft 2 at a transmission ratio i = 1.378 at a slow.

A boost operation in which the drive power is boosted by means of the internal combustion engine is possible. Thus, in particular in the first forward gear Vl or in the third forward gear V3, the electric motor E2 feed electrical power.

A recuperation is possible in all courses.

The electric motor E2 makes it possible to operate the hybrid transmission analogous to the previous example in the CVT mode. In this CVT mode, the couplings KHy2 and Kl are engaged. In the case of the number of teeth mentioned for the embodiment of FIG. 1, an overdrive with a ratio of i = 0.557 results when the electric motor E2 rotates at 1.5 times the speed of the internal combustion engine. By shifting the rotational speeds of the electric motor E2 and / or the internal combustion engine can be in the overdrive area arbitrary translations. In the third hybrid transmission starting the engine with the electric motor E3 is not possible. For example, a conventional starter motor may be provided. A purely electric drive - ie without an internal combustion engine - is possible. A boost operation, in which the drive power is boosted by means of the internal combustion engine is limited possible. Recuperation is possible. The electric motor E3 makes it possible to operate the hybrid transmission analogous to the previous example in the CVT mode.

The fourth hybrid transmission has a similarly good range of functions as the second hybrid transmission. Thus starting of the internal combustion engine with the electric motor E4 is possible. There is no need for a starter motor. The clutches KHy4 and Kl are engaged and thus the electric motor E2 drives the engine 1: 1.

A purely electric ride - i. without combustion engine - is possible. In a first electric driving range, the clutches KHy4, Kl and K3 are engaged and thus the electric motor E4 drives the transmission output shaft 2 1: 1. In a second electric driving range, the clutches KHy4 and B2 are engaged, and thus the electric motor E2 drives the transmission output shaft 2 at a gear ratio i = 2.018.

A boost operation in which the drive power is boosted by means of the internal combustion engine is possible. Thus, limited in the first forward gear Vl, but especially in the third forward gear V3, the electric motor E4 feed electrical power.

A recuperation is possible in all courses. The electric motor E4 makes it possible to operate the hybrid transmission analogous to the previous example in the CVT mode. In this CVT mode, similar to the power flow of the second forward gear V2, the clutches K3 and B2 are engaged. In addition, the clutch Khy4 of the electric motor E4 is engaged.

In the fifth hybrid transmission starting of the internal combustion engine with the electric motor E5 is possible. There is no need for a starter motor. A purely electric ride - i. without combustion engine - is possible. A boost operation in which the drive power is boosted by means of the internal combustion engine is possible. Recuperation is possible. An operation is CVT mode but is not possible.

Thus, the second and the fourth hybrid transmission offer the largest range of functions.

In all embodiments, the respective clutch KHyI or KHy2 or KHy3 or KHy4 or KHy5 of the electric motor can also be dispensed with. This brings with it the restriction that the electric motor El or E2 or E3 or E4 or E5 always rotates.

The rearmost and the central sun gear of the transmission according to FIG. 1 and FIG. 13 can also be designed in an alternative embodiment by means of exclusively an axially very wide toothed wheel. Consequently, then both sun gears inevitably have the same number of teeth. This is a cost-effective and structurally simple design.

The described embodiments are only exemplary embodiments. A combination of the described features for different embodiments is also possible. Further, in particular not described features of the device parts belonging to the invention are to be taken from the geometries of the device parts shown in the drawings.

Claims

claims

1. Planetary automatic transmission with only five

Switching elements, in which a sun gear (13) of a first planetary gear set (4)

- rotatably connected to a transmission input shaft (1) is connected,

- Can be coupled by means of a first switching element (Kl) with a planet carrier (17) of this first planetary gear set (4), the planet gears (23) with a ring gear (22), which by means of the second switching element (Bl) frictionally engaged with a housing (3 ), and

- By means of the third switching element (K2) rotatably coupled to a ring gear (20) of a second planetary gear set (5), said ring gear (20) rotatably connected to a planet carrier (19) of a third planetary gear set (6) whose planet gears (24 )

- On the one hand with a sun gear (16) mesh, which is rotatably coupled to a sun gear (15) of the second planetary set (5) and by means of the fourth switching element (B2) frictionally coupled to the housing (3) and - On the other hand with a ring gear (18) mesh, which is rotatably connected to the planet carrier (17) of the first planetary gear set (4), by means of the fifth switching element (K3) rotatably coupled to the ring gear (22) of the first planetary gear set (4) , wherein a planet carrier (14) of the planet wheels (25) of the second planetary gear set (5) rotatably with the

Transmission output shaft (2) is coupled.

2. Planetary automatic transmission according to claim 1, characterized in that an electric motor (El or E2 or E3 or E4 or E5 or E5) is provided, which at standstill of the transmission input shaft (1) can drive them.

3. Planetary automatic transmission according to one of the preceding claims, characterized in that a CVT mode is provided.

4. Planetary automatic transmission according to claim 3, characterized in that the planet carrier (19) of the third planetary gear set (6) for operation in the CVT mode with an electric motor (E2) can be coupled.

5. Planetary automatic transmission according to claim 4, characterized in that the first switching element (Kl) is engaged in the CVT mode

6. Planetary automatic transmission according to claim 1, characterized in that a total spread (φi _{/ 6} ) is about seven.

7. Planetary automatic transmission according to one of the preceding claims, characterized in that three switching elements (Kl, K2, Bl) in front of the three planetary gear sets (4, 5, 6) are arranged, whereas two switching elements (K3, B2 / E1) behind the three planetary gear sets (4, 5, 6) are arranged.