DE102005021023A1 - Automotive drive system has supplementary torque applied to two drive shafts via superimposed gear - Google Patents

Abstract

An automotive drive system has a variable speed-range gearbox and a differential driving shafts to two wheels. The output torque applied to the shafts many be varied by inputs from a superimposed gear in accordance with predefined parameters. The superimposed gear operates in conjunction with a supplementary motor.

Description

The The invention relates to a drive device for motor vehicles according to the preamble of claim 1.

A Such a drive device is for example in the Z Technical Review (2003) No. 15, pp. 73-76. The torque shift between the output shafts by means of slip-controlled couplings, those with the superposition gearbox interact.

task The invention is a drive device of the generic type to propose, in terms of efficiency, the function and the constructively possible Degrees of freedom is improved.

These Task is according to the invention with the characterizing features of claim 1. advantageous Further developments of the invention characterize the other claims.

According to the invention, it is proposed that the superposition gearbox with at least one extra Drive motor for feeding in and taking off drive torque the output shafts interact. This first causes the Elimination of slip-controlled couplings and the associated Wear and tear Efficiency losses. Furthermore, an active, improved torque shift achieved, with the drive motor in combination with the superposition gear depending on the design, only low drive and braking power (e.g., up to 5% of the power of the prime mover) must and also structurally cheap can be arranged in the range of the differential. The differential can in a known manner a bevel gear differential or a spur gear be. The efficiency of the drive device is the one Differenziales comparable without regulation, since the tax performance only then added or removed must be when actively redistributing power; the system is hence "fail save " Speed ratio the wheels is so adjustable that in every driving situation a 100% blocking the drive wheels allows is, with simultaneous compensation of the speeds when cornering. This can certainly be a sudden Spinning one of the drive wheels (For example, in aqua planing even when cornering, etc.) can be prevented.

Of the at least one drive motor may preferably be a hydrostatic Hydraulic motor or an electric motor. These engines are trouble free in both directions of rotation and as a drive (power supply) or Brake (power consumption) reversible and robust in its function; In addition, they are special in the required drive performance weight low and relatively easy with possibly required supply connections too Mistake.

A advantageous and self-sufficient torque shifting is achieved when two hydraulic motors arranged parallel to the differential and Control technology are connected to each other in such a way that they alternately as a motor or pump are switchable. Depending on requirements (for example, when driving through a curve) becomes the one hydraulic motor switched as a pump and withdraws the inside of the output shaft Torque, which over the other, connected as a motor hydraulic motor of the outer curve output shaft supplied becomes.

A alternative, advantageous embodiment of the invention proposes that a hydraulic motor as a rotating unit in a parallel is integrated to the differential countershaft and that the countershaft over depending at least one gear set with the output shafts driving connected is. Here, the hydraulic motor acts as in the direction of rotation reversible motor connected to an external, e.g. from the drive unit driven hydraulic pump is supplied with drive power and also shifts the torque on the output shafts accordingly. The hydraulic pump may preferably already in the motor vehicle be existing hydraulic pump, e.g. that of a hydraulic power steering system.

Of others can several different speed ranges of the motor vehicle associated gear sets be provided between the drive motor and the output shafts, the by means of one coupling each (for example a simple dog clutch) are switchable. With that you can using relatively lighter and on low drive power designed drive motors are used, due to the different gear ratios the gear sets high torque shifts at low speeds of the Motor vehicle (= low gears with high drive torque) and low torque relocations enable high speeds.

In Another alternative embodiment of the invention may be a drive motor be provided with a planetary gear on a two-piece and cooperates parallel to the differential countershaft cooperates.

In this case, the planetary gear can be designed as a stationary transmission particularly advantageous, the two sun gears on the sections of Vor are arranged countershaft, while the drive motor is drivingly connected to the planet carrier, meshing with the planetary gears with the two sun gears. With a corresponding transmission ratio of the transmission elements is achieved in addition to the structurally simple design that when driving straight ahead of the motor vehicle (both output shafts have same speed) of the planet and accordingly the rotor of the drive motor do not rotate, so are wear-free and not affect the efficiency of the drive device. Due to the enabled power split, the drive motor can also be designed for a lower drive power.

In further, alternative embodiment of the invention is proposed that the differential gear and the superposition gear as coaxially arranged Planetary gear executed are and that acting on the planetary gear drive motor is used for torque input or output. This can be structurally and functionally advantageous a countershaft or a parallel arrangement of the superposition gearbox be avoided.

there can be used to arrange the superposition gear on only one side of the differential of the one output shaft driving planet carrier of the differential gear via a hollow shaft with the arranged on the opposite output shaft superposition gear be connected by love.

The superposition gearbox can also be preferred as summation with two on the hollow shaft and the corresponding output shaft arranged sun gears, a fixed planet carrier and a rotatably mounted planet carrier, wherein the rotatable planet carrier is drivingly coupled to the drive motor, while the planetary gears of the two planet carriers over one rotatable on the output shaft between the two sun gears stored, third sun gear are coupled together. Here too applies that with appropriate translation interpretation of the overlay or Summierungsgetriebes the rotatably mounted planet carrier and the Rotor of the drive motor when driving straight ahead of the motor vehicle do not turn.

alternative can use the superposition gearbox with a sun gear on the hollow shaft of the differential gear and formed with a sun gear on the corresponding output shaft be with the first sun gear with over a fixed planet carrier with planetary gears and a rotatably mounted outer wheel with a second rotatable mounted planet carrier is drivingly connected, whose planet gears with the outer wheel and combing the second sun gear, and wherein the rotatably mounted planet carrier arranged with the stationary Drive motor cooperates.

Independent of The above embodiments of the invention, the superposition gear structurally advantageous in each case directly to the differential gear grown or integrated into this.

Several embodiments The invention are explained in more detail below with further details. The schematic drawing shows in:

1 a bevel gear differential of a drive device for motor vehicles with a superposition gear and two additional parallel hydraulic motors;

2 the differential according to 1 with a split countershaft of the superposition gear and an integrated, co-rotating hydraulic motor;

3 turn the differential according to 1 with a coaxial with the countershaft planetary gear and a stationary hydraulic motor;

4 a spur gear differential of an alternative drive device for motor vehicles with a coaxial planetary gear as a superposition gear and a Nydraulikmotor; and

5 the differential according to 4 , but with a modified planetary gear as a superposition gear.

The 1 shows the bevel gear differential 10 a drive device for motor vehicles whose drive pinion 12 via a propeller shaft, not shown, a speed change gear and a drive unit, in particular an internal combustion engine, is driven in a known manner.

The drive pinion 12 combs with a ring gear 14 a rotatably mounted in a differential housing (not shown) differential housing 16 , In the differential housing 16 are in a known manner two or more bevel gears 18 and two bevel gears 20 rotatably mounted, wherein the axle bevel gears 20 with output shafts 22 . 24 are connected by love. The output shafts 22 . 24 drive the driven wheels 26 of the motor vehicle.

The differential 10 can be a rear differential and / or a built-in change gear front axle differential of the motor vehicle be.

On the output shafts 22 . 24 are each two gears 28 . 30 respectively. 32 . 34 rotatably arranged, with gears 36 . 38 respectively. 40 . 42 Gear sets form as superposition gear 44 with two axis-parallel to the output shafts 22 . 24 arranged drive motors or hydrostatic hydraulic motors 46 . 48 interact.

The hydraulic motors 46 . 48 , For example, bent axis machines of known type, control technology are coupled together so that they are alternately switchable as a pump or as a motor. The hydraulic motors 46 . 48 may optionally have a unitary housing with correspondingly integrated hydraulic channels.

These are the gears 36 . 38 respectively. 40 . 42 carrying waves 50 . 52 the rotors of the hydraulic motors 46 . 48 by means of jaw clutches 54 each with the gear 36 or 38 and the gear 40 or 42 Coupled to the hydraulic motors 46 . 48 depending on the speed of the motor vehicle or a translation position of the transmission in a higher or lower gear ratio toggle.

In straight-ahead driving of the motor vehicle, the output shafts rotate 22 . 24 with the same speed. The hydraulic motors 46 . 48 are control technology via a not shown, hydraulic control valve switched so that they are in idle mode.

When cornering the motor vehicle, the one output shaft rotates 22 . 24 slower than the other output shaft 24 . 22 , In this case, which can be detected, for example, via the steering angle of the steering of the motor vehicle, via an instantaneous yaw rate, via an occurring lateral acceleration, via wheel sensors, etc., the one with the inside, slower rotating output shaft is detected 22 . 24 motionally connected hydraulic motor 46 . 48 switched as a pump and withdraws this output shaft drive torque. About the same time as the engine connected second hydraulic motor 46 . 48 is the drive power of the faster rotating output shaft via the common hydraulic circuit 22 . 24 increases and thus increases the driving dynamics of the vehicle.

By means of couplings 54 also allows the gear ratio of the superposition gear 44 or gear sets 28 . 36 . 32 . 40 and 30 . 38 . 34 . 42 Depending on the speed of the motor vehicle can be switched from low speed to higher speed and vice versa, the hydraulic motors 46 . 48 at low speed can exert a higher drive torque than at higher speeds of the motor vehicle due to the respective switched ratio.

The 2 shows an alternative embodiment of the superposition gear 56 with a rotating hydraulic motor 58 , Unless described, the drive device according to 1 executed and provided with the same reference numerals.

Here is the hydraulic motor 58 in one in two sections 60a . 60b subdivided countershaft 60 integrated, which countershaft 60 paraxial to the differential 10 is arranged.

The section 60a the countershaft 60 is designed as a hollow shaft and with the housing 58a of the hydraulic motor 58 firmly connected. Further, the section carries 60a the one gear 38 of the left gear set 30 . 38 for driving connection with the output shaft 22 ,

The other section 60b the countershaft 60 carries the gear 42 of the right gear set 34 . 42 for driving connection with the opposite output shaft 24 , In addition, the section 60b fixed to the rotor (without reference numeral) of the hydraulic motor 58 connected.

The hydraulic motor 58 is via lines (generally with 62 designated) and a control valve 64 connected to a hydraulic pump (not shown) and thus can in both directions of rotation of the rotor relative to the housing 58a be operated as a motor. The hydraulic pump may be driven, for example, by the internal combustion engine of the drive unit. However, the hydraulic pump may preferably be on the shaft 12 the drive pinion of the differential 10 be arranged so that technically advantageous the speeds between the shaft 12 and the countershaft 60a . 60b in an always defined relationship to each other.

The supply of hydraulic fluid to the hydraulic motor via a rotary feedthrough, for example, the gear 38 and over into the hollow shaft 60a to the housing 58a laid hydraulic lines 62 ,

Thus, according to parameters as above for 1 in turn described drive torque from the one output shaft (eg 22 ) to the other output shaft (eg 24 ) or the driven drive power of the hydraulic motor 58 be added. Instead of the illustrated simple gear sets 30 . 38 respectively. 34 . 42 can also use the couplings 54 Reversible gear sets 28 . 36 . 30 . 38 respectively. 32 . 40 . 34 . 42 according to 1 be provided.

Another alternative superposition gearbox 66 is in the 3 shown. Functionally over attuned parts with the 1 and 2 are provided with the same reference numerals.

It is in the axis parallel to the differential 10 aligned and shaft sections 60a . 60b having countershaft 60 a coaxially arranged, designed as a stationary transmission planetary gear 68 integrated.

The planetary gear 68 has as gear elements two axially immediately adjacent sun gears 70 . 72 on, the non-rotatable with the sections 60a . 60b the countershaft 60 are connected. Furthermore, on the section 60b the countershaft 60 a planet carrier 74 rotatably mounted, the planetary gears 76 (It's just a planetary gear on the drawing 76 visible) with the two sun gears 70 . 72 comb.

The planet carrier 74 is about gears 78 . 80 with the wave 82a the rotor of a stationary arranged hydraulic motor 82 connected by love. The hydraulic motor 82 is in turn according to the hydraulic motor 58 according to 2 connected to an externally driven hydraulic pump and can be operated in both directions of rotation of its rotor.

The transmission ratio of the described planetary gear 68 and the gear sets 30 . 38 respectively. 34 . 42 is designed so that when driving straight ahead of the vehicle or at the same speed rotating output shafts 22 . 24 the planet carrier 74 not spinning while the sun gears 70 . 72 and the planet wheels 76 roll or rotate accordingly.

By controlling the hydraulic motor 82 in one or the other direction of rotation of the rotor is an additional drive torque via the planetary gear 68 to one or the other section 60a . 60b the countershaft 60 and about the gear sets 30 . 38 or 34 . 42 on the corresponding output shaft 22 . 24 exercised. The control parameters are as above for 1 or 2 described executed.

The differential 10 and the superposition gearing 44 . 56 . 66 are preferably arranged in a unitary housing (not shown) and stored with their shafts and gear elements accordingly. Possibly. can the superposition gearbox 44 . 56 . 66 Also provided with separate housings and to the housing of the Differenziales 10 be grown.

A coaxial arrangement of a differential 84 and a superposition gear 86 a drive device as above shows the 4 , Functionally identical parts are denoted by the same reference numerals as in FIGS 1 to 3 Mistake.

Here is the differential gear 84 designed as a planetary gear with the following gear elements and links:
The drive pinion 12 of the differential 84 drives the ring gear 14 on, with the internally toothed, cup-shaped outer wheel 87 is firmly connected. The outer wheel 87 meshes with radially outer planetary gears 88 and these with radially inner planetary gears 90 attached to a common planet carrier 92 are rotatably mounted. The radially inner planet wheels 90 also comb with the sun gear 94 of the planetary gear or differential 84 ,

The sun wheel 94 is as the one output element with the right output shaft 24 rotatably connected while the planet carrier 92 as the other output element with the left output shaft 22 is firmly connected.

The planet carrier 92 of the differential 84 also has a hollow shaft opposite its output side 92a auf, in a manner to be described with the coaxial adjacent superposition gearing 86 interacts.

The superposition gearbox 86 is as a summation with two planetary gear sets designed as a stationary gear 95 . 96 geared as follows:
There are initially three axially adjacent sun gears 98 . 100 . 102 provided, of which a sun wheel 98 on the hollow shaft 92a rotatably attached, the central sun gear 100 on the output shaft 24 is rotatably mounted and the third sun gear 102 rotatably with the output shaft 24 connected is.

The two sun wheels 98 . 100 comb with planet wheels 104 a rotationally supported planet carrier 106 , Furthermore, the two sun gears 100 . 102 with other planet wheels 108 engaged on a planet carrier 110 are rotatably mounted.

The planet carrier 110 Finally, on the output shaft 24 rotatably mounted and via a gear set 112 . 114 with a hydraulic motor 116 connected as above 3 described in both directions reversible and operable via an external hydraulic pump.

The gear ratios of the summation gear 95 . 96 are in turn designed so that when driving straight ahead of the motor vehicle with the same rotating output shafts 22 . 24 the planet carrier 110 not turning and thus also the hydraulic motor 116 is not subject to wear.

With activated hydraulic motor 116 In one or the other direction of rotation can additional drive torque to one or the other output shaft 22 . 24 be exercised, with the power branching of the summation 95 . 96 only relatively low drive power from the hydraulic motor 116 be applied, so this is low weight interpretable low.

The planetary differential 84 and the superposition gearbox 86 are preferably arranged in a common housing (not shown) and rotatably mounted accordingly.

The 5 shows one opposite the 4 modified superposition gearbox 86 ' , wherein functionally identical parts are again provided with the same reference numerals.

According to 5 are the two planetary gear sets 95 . 96 not a third sun wheel ( 100 ), but via a common, internally toothed outer wheel 118 geared together technically. That means that with the sun gears 98 and 102 meshing planet gears 104 . 108 on the common outer wheel 118 roll off. The outer wheel 118 is in the housing, not shown, of the superposition gear 86 ' via a roller bearing 120 rotatably mounted.

The function of the superposition gearbox 86 '' is with the function of the superposition gear 86 according to 4 comparable; This also applies to the arrangement and control of the hydraulic motor 116 , Due to the omission of the third sun wheel ( 100 ) However, results in an axially shorter and less meshing requiring design for the superposition gearbox 86 '' ,

The invention is not limited to the described embodiments. Thus, instead of the described hydrostatic hydraulic motors or hydraulic machines 46 . 48 . 58 . 82 . 116 Also be used electric motors, as described above, the drive torque to the output shafts 22 . 24 shift accordingly and improve the driving stability and driving dynamics of the motor vehicle depending on predetermined control parameters.

Claims (14)

Drive device for motor vehicles, with at least one drive unit which drives via a speed change gearbox and at least one differential two output shafts connected to driven wheels of the motor vehicle, wherein the output torque is variable at the output shafts by means of an additional superposition gearbox depending on predetermined parameters, characterized in that the superposition gearbox ( 44 ; 56 ; 66 ; 86 ) with at least one additional drive motor ( 46 . 48 ; 58 ; 82 ; 116 ) for the supply and decrease of output torque on the output shafts ( 22 . 24 ) cooperates. Drive device according to claim 1, characterized in that the at least one drive motor is a hydrostatic hydraulic motor ( 46 . 48 ; 58 ; 82 ; 116 ). Drive device according to claim 1, characterized in that the at least one drive motor ( 46 . 48 ; 58 ; 82 ; 116 ) is an electric motor. Drive device according to one or more of the preceding claims, characterized in that two alternately or simultaneously torque-feeding drive motors ( 46 . 48 ) are provided by means of at least two gear sets 30 . 38 . 34 . 42 ) with the output shafts ( 22 . 24 ) are drivingly connected. Drive device according to claim 4, characterized in that the two hydraulic motors ( 46 . 48 ) parallel to the differential ( 10 ) are arranged and control technology connected to each other in such a way that they can be switched alternately as a motor or pump. Drive device according to one or more of the preceding claims, characterized in that a hydraulic motor ( 58 ) as a co-rotating unit in a parallel to the differential ( 10 ) arranged countershaft ( 60 ) and that the countershaft ( 60 ) each have at least one gear set ( 30 . 38 . 34 . 42 ) with the output shafts ( 22 . 24 ) is drivingly connected. Drive device according to one or more of the preceding claims, characterized in that a plurality of different speed ranges of the motor vehicle associated gear sets ( 28 . 36 . 30 . 38 . 32 . 40 . 34 . 42 ) between the drive motor ( 46 . 48 ) and the output shafts ( 22 . 24 ) are provided, which by means of a respective coupling ( 54 ) are switchable. Drive device according to one or more of the preceding claims, characterized in that a drive motor ( 82 ) provided with a planetary gear ( 68 ) on a two-part and parallel to the differential ( 10 ) arranged countershaft ( 60 ) cooperates. Drive device according to claim 8, characterized in that the planetary gear ( 68 ) is designed as a stationary transmission, whose two sun gears ( 70 . 72 ) on the sections ( 60a . 60b ) of the countershaft ( 60 ) are arranged while the drive motor ( 82 ) with the planetary wheel carrier ( 74 ) is drivingly connected, whose planet gears ( 76 ) with the two sun wheels ( 70 . 72 ) comb. Drive device according to one or more of the preceding claims 1 to 3, characterized in that the differential gear ( 84 ) and the superposition gearing ( 86 ) are designed as a coaxially arranged planetary gear and that acting on the planetary gear drive motor ( 116 ) is used for torque supply and removal. Drive device according to claim 10, characterized in that the one output shaft ( 22 ) driving planet carrier ( 92 ) of the differential gear ( 84 ) via a hollow shaft ( 92a ) with the on the opposite output shaft ( 24 ) arranged superimposed gear ( 86 ; 86 ' ) is drivingly connected. Drive device according to Claims 10 and 11, characterized in that the superposition gearing ( 86 ) as a summation gear with two on the hollow shaft ( 92a ) and the corresponding output shaft ( 24 ) arranged sun wheels ( 98 . 102 ), a fixed planet carrier ( 106 ) and a rotatably mounted planet carrier ( 110 ), wherein the rotatable planet carrier ( 110 ) drivingly with the drive motor ( 116 ) while the planet gears ( 104 . 108 ) of the two planet carriers ( 106 . 110 ) via a on the output shaft ( 24 ) between the two sun gears ( 98 . 102 ) rotatably mounted, third sun gear ( 100 ) are coupled together. Drive device according to Claims 10 and 11, characterized in that the superposition gearing ( 86 ' ) with a sun wheel ( 98 ) on the hollow shaft ( 92a ) of the differential gear ( 84 ) and with a sun wheel ( 102 ) on the corresponding output shaft ( 24 ), wherein the first sun gear ( 98 ) with a fixed planet carrier ( 106 ) with planetary gears ( 104 ) and a rotatably mounted outer wheel ( 118 ) with a second rotatably mounted planet carrier ( 110 ) is drivingly connected, the planetary gears ( 108 ) with the outer wheel ( 118 ) and the second sun gear ( 102 ), and wherein the rotatably mounted planet carrier ( 110 ) with the stationarily arranged drive motor ( 116 ) cooperates. Drive device according to one or more of the preceding claims, characterized in that the superposition gearing ( 44 ; 56 ; 66 ; 86 ; 86 ' ) directly to the differential gear ( 10 ; 84 ) is built-in or integrated into this.