CN108501712A - A kind of between centers torque universe actively distributes full-time four-wheel drive system - Google Patents

Abstract

The invention discloses a kind of between centers torque universes actively to distribute full-time four-wheel drive system, including：Power input shaft；Front axle；Rear axle；First planetary gear train comprising the first sun gear, the first planetary gear, the dismountable first planet carrier equipped with hollow shaft and the first ring gear equipped with hollow shaft；Second planetary gear train comprising the second sun gear, the second planetary gear, the second planet carrier and the second ring gear；Third planet train comprising third sun gear, the third line star-wheel, third planet carrier and third ring gear；TV controls motor, is equipped with hollow output shaft of the empty set on rear axle, and it is connect by deceleration mechanism with third ring gear；Input sprocket, center and the hollow shaft of the first ring gear are connected；Power transmission is realized by transmission chain between output chain gear, with input sprocket, and it is connected with front axle.Between centers torque universe provided by the invention actively distributes full-time four-wheel drive system, and the function of the arbitrary distribution of torque between antero posterior axis may be implemented.

Description

A full-time four-wheel drive system with global active distribution of inter-axle torque

technical field

The invention belongs to the technical field of drive systems of four-wheel drive vehicles, in particular to a full-time four-wheel drive system with full-range active distribution of inter-axle torque.

Background technique

In recent years, with the improvement of people's living standards and the continuous advancement of technology, people have put forward higher and higher requirements for the quality of cars. The car has gradually transitioned from the initial demand for transportation tools to safety, comfort, In terms of economy and driving pleasure, people's demand for multi-function, multi-road driving and high-performance vehicles is also increasing year by year, such as high-performance four-wheel drive SUVs or high-performance four-wheel drive cars. These models are not only increasingly demanded in the internal combustion engine drive market, such as the Audi Q5 SUV with a sports differential, the Acura TLX mid-size sedan with a SH-AWD four-wheel drive system, etc., even for hybrid or electric vehicles. The mainstream development trend of the market, such as Volvo XC60T8E drive hybrid and Tesla Model S.

According to the number of driving wheels, the driving forms of automobiles mainly include two-wheel drive and four-wheel drive. Four-wheel drive is divided into timely four-wheel drive, full-time four-wheel drive, and part-time four-wheel drive. According to the layout of the transmission system, it can be divided into centralized drive and distributed drive. The former is used in traditional internal combustion engine vehicles and new energy vehicles, while the latter is often driven by hub motors or wheel motors, so it is generally used by new energy vehicles, especially It is used by electric vehicles, which is called electric wheel independent drive vehicles. Distributed in-wheel motor drive can easily realize four-wheel drive, and in-wheel motors generally directly drive the wheels without too many transmission systems, so the structure is simple, the space occupation is small, and the transmission efficiency is high, which is an excellent transmission form. However, at this stage, the technical bottlenecks such as the general low power density of hub motors, the poor reliability of the motor due to the harsh working environment, and the increase in the unsprung mass of the hub motor lead to the reduction of vehicle comfort and other technical bottlenecks seriously affect its large-scale use, so it is currently only some concept cars or small cars. Batch prototypes are in use, and most electric vehicles are still using a centralized drive form similar to internal combustion engine-driven vehicles. Internal combustion engine or centralized hybrid powertrain (Hybrid Powertrain) as a centralized power source is often arranged in the engine compartment of the front axle. This single centralized power source (for hybrid systems, there are generally multiple power sources, but mainstream It is integrated with the internal combustion engine, transmission or coupling device to form a centralized hybrid powertrain) can only use the traditional central centralized transmission system to transmit power to the wheels. As mentioned above, electric vehicles generally use a single motor with a lower development cost to match the traditional drive axle in the form of a central centralized drive axle to drive the wheels. Drive, you need a transfer device or coupling device to transfer part of the power to other drive axles.

According to different four-wheel drive capacity design requirements, for the aforementioned three four-wheel drive forms, the power transfer devices or coupling devices of the above three power models are also different. For example, for timely four-wheel drive vehicles, the transmission output On the shaft side, two identical gears are externally meshed at the same time to transmit power to the front and rear axles, and an electromagnetic multi-disc clutch is added before going to the non-main drive axle (usually the rear axle) to transmit power to the rear axle through the drive shaft in a timely manner. When the electromagnetic clutch is engaged, the rear axle generally gets up to half of the total drive torque. The so-called timely means that the power is not transmitted to the rear axle after the clutch is engaged at all times, but generally the four-wheel drive can only be realized when the front wheels are slipping or when the four-wheel drive is required for a short time; and for the full-time four-wheel drive, the central differential ( That is, the inter-axle differential) connects the transmission shafts of the front and rear axles. The torque distribution of the front and rear axles is generally evenly distributed, and some use unequal distribution. In order to prevent the driving force of the other axle from falling when the wheel of one axle slips, and the passability is reduced, the central differential of this type of full-time four-wheel drive system generally uses a limited slip differential or a differential The central differential with locking function is used to realize the transfer of torque between the front and rear axles; for part-time four-wheel drive, a central differential is often added in the transmission or after the transmission, which is realized by switching the gears in the central differential. Power is transmitted to the non-primary drive axle (typically the front axle). The central differential generally also has a low gear to further amplify the engine torque to meet the requirements of extreme off-road capability. Although the above three four-wheel drive forms use different mechanisms to transmit power to the four wheels, these mechanisms are inherited from the original internal combustion engine four-wheel drive vehicles. Even for electric vehicles, most single-motor electric four-wheel drive vehicles Also all adopt the transfer device or the power coupling device of traditional internal combustion engine four-wheel drive vehicle to realize four-wheel drive, all do not have the electric four-wheel drive system targeted development for the characteristic of electric vehicle and market demand, do not have any novelty at all. In addition, more importantly, the above-mentioned four-wheel drive mechanisms all have such and such shortcomings. For example, because most of the working conditions of a timely four-wheel drive vehicle are driven by a single axle (generally the front axle), occasionally the front wheels enter low adhesion or hang in the air and skid. , The electromagnetic multi-disc clutch is quickly combined to transfer part of the driving torque to another axle (usually the rear axle) attached to drive the vehicle, ensuring the vehicle's power and driving stability, and can also improve the passing performance to a certain extent. The important thing is that it has good economy because it is driven by single shaft most of the time. However, because its transmission mode is gear transmission plus electromagnetic multi-disc clutch, it generally can only transfer and output no more than half of the maximum output torque of the vehicle to the non-main driving wheels in a short time. The passing performance is mediocre, only mild off-road, but the driving economy is the best. Full-time four-wheel drive vehicles are driven by four wheels during the whole driving time, and because they are generally equipped with inter-axle limited-slip differentials or differential locks, the vehicle's power, driving stability and passability are all better than those of other vehicles. Timely four-wheel drive is much stronger, but due to its complex structure and high cost, it is generally only used in mid-to-high-end four-wheel drive SUVs or high-end four-wheel drive cars, and because it is always four-wheel drive, it cannot achieve active torque distribution until single-axis drive way, so the driving economy is poor. Part-time four-wheel drive is generally in the form of rear-wheel drive, and the driving economy is good when driving with a single axle. When the power is transmitted to the front and rear axles at the same time by manipulating the central differential to become four-wheel drive, since it generally does not have a central differential, it cannot drive at high speed on normal paved roads, and can only perform low-speed off-road on non-paved roads. . Moreover, due to the body structure, vehicle weight, no differential, tires, etc., the driving economy and handling stability when combined with four-wheel drive are far from other four-wheel drive vehicles, so it is difficult to apply to high-end four-wheel drive cars and high-performance SUVs. .

On the whole, the full-time four-wheel drive form is relatively good, but because the ordinary differential it adopts has the characteristics of "differential speed and torque", when the road surface adhesion of the front and rear axles of the car is inconsistent, it may cause the axle on the side with low adhesion. The wheels on the car slipped, causing the car to be trapped and unable to move. Or when the car accelerates rapidly, the load is transferred from the front axle to the rear axle, which may also cause the front axle wheels to reach the adhesion limit and slip to cause the car to lose stability. Although various inter-axle limited-slip differentials or inter-axle differential locks in the prior art can partially or completely lock the transmission shafts connected to the front and rear axles, so as to realize the transfer of torque from low-attachment axles to high-attachment axles, avoiding Wheel slipping improves vehicle passability, but the transfer and distribution of torque between axles is unidirectional, and the driving torque can only be transferred from the fast-rotating axle to the slow-rotating axle, which cannot improve the maneuverability of the vehicle under various road conditions performance and drive performance. The central differential on a traditional car can only change the speed of the two axles, but cannot distribute the torque. Although the central differential can realize the distribution of the torque between the axles, it cannot realize the directional distribution of any torque value between the axles. .

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and to meet the performance requirements of four-wheel-drive electric vehicles, four-wheel-drive hybrid vehicles, and four-wheel-drive traditional internal combustion engine vehicles, and provide a full-time four-wheel drive with active distribution of inter-axle torque in the entire domain. Drive system, which uses a motor as the power source of torque distribution between axles, can make the total driving torque of a full-time four-wheel drive vehicle be actively distributed between the front and rear axles in any proportion, and overcomes the existing full-time four-wheel drive system. The drive technology can only passively distribute the total drive torque within a certain proportion, which improves the overall performance of the car.

The technical scheme provided by the invention is:

A full-time four-wheel drive system with global active distribution of inter-axle torque, including:

power input shaft;

front axle;

rear axle;

a first planetary gear train comprising a first sun gear, a first planet gear, a first planet carrier and a first ring gear;

Wherein, the first planet carrier is fixedly connected with the power input shaft, and it is provided with a hollow shaft, and the hollow shaft of the first planet carrier is sleeved on the rear axle; the first sun gear and the The rear shaft is fixedly connected, the first inner ring gear is provided with a hollow shaft, and the hollow shaft of the first inner ring gear is sleeved on the power input shaft;

a second planetary gear train comprising a second sun gear, a second planet gear, a second planet carrier and a second ring gear;

Wherein, the second sun gear is fixedly connected to the hollow shaft of the first planet carrier, and the second ring gear is fixedly connected to the four-wheel drive system housing;

a third planetary gear train, which includes a third sun gear, a third planet gear, a third planet carrier and a third ring gear;

Wherein, the third sun gear is fixedly connected to the rear axle; the third planet carrier is fixedly connected to the second planet carrier;

TV control motor, which is provided with a hollow output shaft, the hollow output shaft is sleeved on the rear axle, and the hollow output shaft is connected with the third ring gear through a reduction mechanism;

an input sprocket, the center of which is fixedly mounted on the hollow shaft of the first inner ring gear;

an output sprocket fixedly connected to the front axle;

Wherein, the input sprocket and the output sprocket perform power transmission through a transmission chain.

Preferably, the second planetary gear train and the third planetary gear train have the same planetary row characteristic parameters and planetary row types.

Preferably, the reduction mechanism includes a fourth planetary gear train, which includes a fourth sun gear, a fourth planetary gear, a fourth planet carrier, and a fourth ring gear;

Wherein, the fourth sun gear is fixedly connected to the hollow output shaft; the fourth planet carrier is fixedly connected to the third ring gear; the fourth ring gear is fixed to the housing of the four-wheel drive system connect.

Preferably, the transmission ratio of the input sprocket to the output sprocket is 1.

Preferably, the first planetary carrier is a detachable planetary carrier, which can be disassembled into several parts, and each part can be assembled separately, and then the parts are assembled and fixed together, so that the first A sun gear is wrapped inside it.

Preferably, the hollow shaft of the first planet carrier is connected to the rear shaft through a bearing.

Preferably, the hollow shaft of the first ring gear is connected to the power input shaft through a bearing.

Preferably, the TV control motor is a hollow shaft inner rotor motor.

Preferably, the hollow output shaft is connected to the rear shaft through a bearing.

Preferably, the stator and casing of the TV control motor are fixedly connected to the casing of the four-wheel drive system.

Preferably, the hollow output shaft of the TV control motor is splined to the central hole of the fourth sun gear.

The beneficial effects of the present invention are:

1. The full-time four-wheel drive system with full-range active distribution of inter-axle torque provided by the present invention overcomes the technical defect that the existing full-time four-wheel drive system can only change the torque distribution ratio of the front and rear axles within a certain range, and can realize the torque distribution ratio between the front and rear axles. The function of arbitrarily distributing the torque between them, and the response is quick; in the extreme case, when the single shaft slips, the entire powertrain output torque is transferred to another shaft with good adhesion, so as to realize the single shaft drive, which can be compared with the hub motor drive. Without reducing the total output power, the power performance of the whole vehicle is guaranteed.

2. The full-time four-wheel drive system that actively distributes the inter-axle torque in the whole area provided by the present invention overcomes that the existing full-time four-wheel drive system can only passively change the torque of the front and rear axles according to the speed difference between the front and rear axles or the internal friction torque of the differential. The technical defect of distribution can realize the function of actively changing the torque distribution ratio between the front and rear axles at any time, and the response is quick.

3. The full-time four-wheel drive system with global active distribution of inter-axle torque provided by the present invention overcomes the fact that the existing full-time four-wheel drive system can only transfer the driving torque from one axis with a fast speed to one-way speed during torque distribution. The technical defect of the other slow shaft can realize the function of actively distributing torque in any direction between the fast and slow shafts, that is, it can be transferred from the fast speed shaft to the slow speed shaft, or from the speed The function of transferring the slow axis to the fast axis.

4. The full-time four-wheel drive system with full-range active distribution of inter-axis torque provided by the present invention, compared with the independent drive of the hub motor, does not need to control each hub motor separately, but only needs to control one motor to adjust each axis. The driving torque, the control system is simple and reliable, and the control is easy to realize.

5. The full-time four-wheel drive system with global active distribution of inter-axle torque provided by the present invention has a compact structure and a reasonable layout. Compared with the independent drive of the hub motor, it is arranged as a sprung mass, which has little impact on the ride comfort of the vehicle.

6. The full-time four-wheel drive system provided by the present invention has the fundamental technical characteristics of active torque distribution in the whole range of the torque, which can improve the power performance, economy, turning maneuverability, handling stability and Through the demand of sex, improve the overall performance of the vehicle.

Description of drawings

Fig. 1 is a schematic structural diagram of a full-time four-wheel drive system with active distribution of inter-axle torque in the entire area according to the present invention (taking the TV control motor placed on the rear axle as an example).

Fig. 2 is a schematic diagram of the torque flow of the full-time four-wheel drive system with inter-axle torque global active distribution according to the present invention when the TV control motor does not work.

Fig. 3 is a schematic diagram of the torque flow of the full-time four-wheel drive system with active distribution of inter-axle torque in the whole area according to the present invention when the TV control motor is active.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings, so that those skilled in the art can implement it with reference to the description.

As shown in Figure 1, the present invention provides a full-time four-wheel drive system with active distribution of inter-axle torque in the entire range, which mainly consists of a central differential 2000, a double planetary row TV coupling mechanism 3000, a TV control motor reduction mechanism 4000 and a TV The control motor 5001 constitutes.

The central differential 2000 is located near the power input end and is mainly composed of a first planetary gear train 2010 , including a sun gear 2011 , three planetary gears 2012 evenly distributed along the circumferential direction, an inner ring gear 2013 and a planetary carrier 2014 . Wherein, the center of the sun gear 2011 and the rear axle 5002 are fixedly connected together by splines. The diameter of the forward extension part of the inner ring gear 2013 becomes smaller and becomes a hollow stepped hollow shaft. The diameter of the middle part of the outer diameter of the hollow shaft is larger than the diameter of the end, and the outer diameter of the end is processed with splines. The power input shaft 5003 runs from the inside of the hollow shaft to After passing through, a pair of bearings are arranged between the two to reduce friction and mutual support during relative rotation between the two. The planetary carrier 2014 is a detachable planetary carrier, which can be disassembled into several parts. During assembly, each part can be carried out separately. The diameter of the rear extension of the planet carrier 2014 becomes smaller and becomes a hollow stepped hollow shaft. The diameter of the middle part of the outer diameter of the hollow shaft is larger than the diameter of the end, and the outer diameter of the end is processed with splines. The rear shaft 5002 passes through the hollow shaft from front to back However, a pair of bearings are arranged between the two to reduce friction and support each other during relative rotation between the two. At the same time, the center of the left end of the planet carrier 2014 is fixedly connected with the power input shaft 5003 through a spline. The power input shaft 5003 is the power input end of the vehicle, which can be provided by a traditional internal combustion engine or other rotating power sources including electric motors. power. When the power source is a traditional internal combustion engine, the power input shaft 5003 is connected to the output end of the power assembly composed of the internal combustion engine and the matching transmission; when the power source is an electric motor, it can be directly connected to the output end of the electric motor, or it can be connected to the electric motor and a transmission with few gears The composed powertrain output terminals are connected.

The double-planet row TV coupling mechanism 3000 mainly includes two single-row planetary gear trains: the second planetary gear train 3020 and the third planetary gear train 3030 . These two single-row planetary gear trains have the same planetary row characteristic parameter and planetary row type, and the characteristic parameter is greater than 1 (the described planetary row characteristic parameter is generally defined in the mechanical field, that is, the ring gear and the planetary row in the planetary row ratio of the number of teeth of the sun gear). The second planetary gear train 3020 includes a sun gear 3021 , three planetary gears 3022 uniformly distributed along the circumferential direction, an inner ring gear 3023 and a planet carrier 3024 . Wherein, the center of the sun gear 3021 is fixedly connected with the end of the hollow shaft extending backward of the planetary carrier 2014 of the first planetary gear train 2010 through splines. The inner ring gear 3023 is fixedly connected with the four-wheel drive system housing 6003 . The third planetary gear train 3030 includes a sun gear 3031 , three planetary gears 3032 uniformly distributed along the circumferential direction, an inner ring gear 3033 and a planet carrier 3034 . Wherein, the sun gear 3031 and the rear shaft 5002 extending from its center to the rear are connected together by splines, and the planet carrier 3034 is fixedly connected with the planet carrier 3024 of the second planetary gear train 3020 .

The TV control motor reduction mechanism 4000 is mainly composed of a fourth planetary gear train 4040 . The fourth planetary gear train 4040 includes a sun gear 4041 , three planetary gears 4042 uniformly distributed along the circumferential direction, an inner ring gear 4043 and a planet carrier 4044 . Wherein, the ring gear 4043 is fixedly connected with the four-wheel drive system housing 6003 , and the planet carrier 4044 is fixedly connected with the ring gear 3033 of the third planetary gear train 3030 . It should be noted that, in this embodiment, the TV control motor reduction mechanism 4000 adopts a single-row planetary gear train, and the reduction mechanism composed of other types of planetary gear trains or multi-row planetary gear trains does not constitute a difference from the present invention. new structure.

The TV control motor 5001 is a hollow-shaft inner rotor motor, the rear axle 5002 connected to the rear drive axle passes through the center hole of the hollow inner rotor shaft without contact, and a pair of bearings are arranged between the two to reduce the two Friction and mutual support between the two when they rotate relative to each other. The outer diameter of the front end of the hollow-shaft inner rotor is processed with splines, and is connected with the center hole of the sun gear 4041 of the fourth planetary gear train 4040 through splines, so that the output torque of the TV control motor 5001 can be transmitted to the fourth planetary gear train 4040. Four planetary gear train 4040. The stator of the TV control motor 5001 and its housing are fixedly connected with the four-wheel drive system housing 6003 , and are supported and fixed by the four-wheel drive system housing 6003 .

The input sprocket 1000 realizes the power transmission between the input sprocket 1000 and the output sprocket 6000 by using the transmission chain 6002 . Compared with the gear meshing transmission mode, this chain transmission mode can realize the parallel arrangement with a certain distance between the front axle 6001 and the rear axle 5002 without increasing the diameter of the gears. The input sprocket 1000 is identical to the output sprocket 6000 in tooth number and diameter. The output sprocket 6000 is splined to the front shaft 6001 through the center hole; at the same time, the front end of the input sprocket 1000 extends forward from the inner ring gear 2013 of the first planetary gear train 2010 and is connected to the front end spline after being installed. Keyed connection, the stepped shaft diameter reducing part of the extension part of the inner ring gear 2013 can play the role of limiting the axial direction of the input sprocket 1000.

In addition, all the planetary gear trains included in the full-time four-wheel drive system with inter-axle torque global active distribution in the present invention have characteristic parameters greater than 1.

The full-time four-wheel-drive system with full-range active distribution of inter-axle torque according to the present invention realizes the integration with the core components by setting the central differential 2000 with unequal torque distribution, the co-frame double planetary row TV coupling mechanism 3000 and the chain transmission The power input shaft 5003 connected to the power assembly of the engine or electric motor is connected to the front axle 6001 and the rear axle 5002. The front axle 6001 then transmits the power to the front axle of the car, and the rear axle 5002 then transmits the power to the rear axle of the car, so the vehicle Realized four-wheel drive work. The forward or reverse torque output of the TV control motor 5001 can control the total drive torque input from the power input shaft 5003 to be arbitrarily distributed on the front axle or the rear axle, and in extreme cases, the total input torque can be all distributed to one drive The bridge realizes single-bridge drive. The above-mentioned structure and connection relationship realize the global active arbitrary directional distribution of the total input torque of the powertrain between the front and rear axles.

The full-time four-wheel drive system with full-range active distribution of inter-axle torque mainly involves four working conditions: the TV control motor 5001 is not activated when driving in a straight line, the TV control motor 5001 is not activated when driving in a turn, the TV control motor 5001 is activated when driving in a straight line, and the TV control motor 5001 is turned on when turning. Travel TV control motor 5001 starts. The four working conditions are described below:

(1) TV control motor 5001 does not start when traveling straight.

When the car is running at a constant speed on a good level road, the driving wheels of the front and rear axles are well attached to the road, and the axle load will not change significantly. Therefore, there is no need for directional distribution of torque between the front and rear axles. At this time, the TV control motor 5001 Without the control electric signal, the TV control motor 5001 does not work, and the torque input by the powertrain through the power input shaft 5003 passes through the center differential 2000 to transmit the power to the sun gear 2011 and the ring gear 2013 of the first planetary gear train 2010 , the sun gear 2011 then transmits the torque to the rear axle 5002, so that the rear axle driving wheels of the automobile can obtain driving torque. At the same time, the inner ring gear 2013 transmits the torque to the input sprocket 1000, and the input sprocket 1000 transmits the torque to the output sprocket 6000 through the transmission chain 6002, and then further transmits the torque to the front axle 6001, so that the front axle of the automobile The drive wheels receive drive torque. At this time, the car is in a full-time four-wheel drive state.

In terms of speed relationship, the rotation direction of the front axle and the rear axle is set to be positive when driving the car forward, and negative when driving backward. Assuming that the speeds of the front and rear axles of the automobile are both n, that is, the speed n _S1 of the sun gear 2011 of the first planetary gear train 2010 and the speed n _R1 of the ring gear 2013 are equal, that is, n _S1 =n _R1 =n. In order to reduce the inertia loss and counter electromotive force energy consumption caused by motor idling as much as possible, the TV control motor 5001 should be avoided from idling, that is, the speed of the sun gear 4041 of the fourth planetary gear train 4040 connected to the hollow inner rotor of the TV control motor 5001 should be avoided. n _S4 =0. Since the ring gear 4043 of the fourth planetary gear train 4040 is firmly connected with the four-wheel drive system housing 6003 and its rotational speed n _R4 =0, the rotational speed n _H4 of the planet carrier 4044 of the fourth planetary gear train 4040 =0. Since the ring gear 3033 of the third planetary gear train 3030 is fixedly connected with the planet carrier 4044 of the fourth planetary gear train 4040 , the rotational speed n _R3 of the ring gear 3033 =0. And because the ring gear 3023 of the second planetary gear train 3020 is firmly connected with the four-wheel drive system housing 6003 , the rotation speed n _R2 of the ring gear 3023 =0. And because the planetary carrier 3024 of the second planetary gear train 3020 is fixedly connected with the planetary carrier 3034 of the third planetary gear train 3030, the rotational speed n _H2 of the planetary gear 3024 is the same as the rotational speed n _H3 of the planetary gear 3034, i.e. n _H2 = n _H3 , and since the second planetary gear system 3020 and the third planetary gear system 3030 have the same planetary row characteristic parameter and planetary row type, the rotational speed n _S2 of the sun gear 3021 of the two planetary gear systems and the speed n S2 of the sun gear 3031 can be obtained The rotational speed n _S3 is the same, ie n _S2 =n _S3 . And because the sun gear 3031 of the third planetary gear train 3030 and the sun gear 2011 of the first planetary gear train 2010 are connected as a whole through the rear axle 5002, so the rotational speeds of the two are the same, that is, n _S1 = n _S3 , then n _S1 = n _S2 . Because the planetary carrier 2014 of the first planetary gear train 2010 is fixedly connected with the sun gear 3021 of the second planetary gear train 3020, the rotational speed n _H1 of the planetary gear train 2014 is the same as the rotational speed n _S2 of the sun gear 3021, i.e. n _H1 =n _S2 , then the rotational speeds of the sun gear 2011 and the planetary carrier 2014 are the same, that is, n _S1 = n _H1 , according to the formula for the rotational speed of a single planetary row, the rotational speeds of the sun gear 2011 and the ring gear 2013 of the first planetary gear train 2010 are exactly the same, That is, n _S1 =n _R1 . In addition, since the transmission ratio of the input sprocket 1000 and the output sprocket 6000 is 1, the rotational speeds of the front and rear axles of the automobile are exactly the same at this time. This is consistent with the conclusion derived above that the front and rear axle speeds are the same when the car is running straight, so it can be ensured that the TV control motor 5001 will not run idling at this time, saving energy.

In terms of torque relationship, assuming that the torque input by the powertrain via the power input shaft 5003 is T ₀ (T ₀ is a positive value), then the torque T _H1 of the planet carrier 2014 of the first planetary gear train 2010 = T ₀ , so according to the torque formula of a single planetary row, the torques of the sun gear 2011 and the ring gear 2013 of the first planetary gear train 2010 are respectively (where k ₁ is the characteristic parameter of _the planetary row of the first planetary gear train 2010, and k ₁ >1), then the input torques T _front and T rear obtained by the front and rear axles are respectively And T _before > T _after , it can be seen that the full-time four-wheel drive system with global active distribution of inter-axle torque according to the present invention is in normal four-wheel drive, and the front axle is the main drive axle. At this time, the flow direction of torque distribution is shown in Fig. 2 .

(2) Turning TV control motor 5001 does not start.

In this working condition, because the distance between the front and rear driving wheels of the car and the instant center of the car's turning is different when the car is turning, that is, the average turning radius of the front and rear axles is not the same, the average speed of the two wheels of the front axle is slightly higher than the average speed of the two wheels of the rear axle. Rotating speed, this causes the front and rear axle rotating speeds in the present invention that connects front and rear axle to also have slight rotating speed difference. The speed difference is realized by the central differential 2000 without changing the torque distribution of the front and rear axles to realize the adaptive differential, that is, the ring gear 2013 of the first planetary gear train 2010 connected to the front axle 6001 and the ring gear 2013 connected to the rear axle 5002 There is a certain speed difference between the two sun gears 2011 of the first planetary gear system 2010, that is, n _R1 ≠ n _S1 , according to the single planetary row speed formula, both the planetary carrier 2014 and the sun gear 2011 of the first planetary gear system 2010 can be obtained The speed has a certain speed difference, that is, n _H1 ≠ n _S1 , because the planet carrier 2014 and the sun gear 2011 of the first planetary gear system 2010 are respectively connected to the sun gear 3021 of the second planetary gear system 3020 and the sun gear of the third planetary gear system 3030 3031 is splined, so at this time, the sun gear 3021 of the second planetary gear train 3020 and the sun gear 3031 of the third planetary gear train 3030 have a very small rotational speed difference, namely n _S2 ≠ n _S3 . And because the characteristic parameters of the second planetary gear train 3020 and the third planetary gear train 3030 are exactly the same and the two planetary carriers 3024 and 3034 are solidly connected as one, that is, the rotational speeds of both are n _H2 =n _H3 , then according to the single planetary row rotational speed formula, It can be obtained that there is a certain speed difference between the ring gear 3023 of the second planetary gear set 3020 and the ring gear 3033 of the third planetary gear set 3030, that is, n _R2 ≠ n _R3 , because the inner gear of the second planetary gear set 3020 The ring 3023 is fixedly connected with the four-wheel drive system housing 6003, so n _R2 =0, then the rotational speed n _R3 ≠0 of the ring gear 3033 of the third planetary gear train 3030 can be obtained. Since the planet carrier 4044 of the fourth planetary gear system 4040 is fixedly connected with the ring gear 3033 of the third planetary gear system 3030, the rotational speed n _H4 =n _R3 of the planet carrier 4044 of the fourth planetary gear system 4040 ≠0, at this time due to The ring gear 4043 of the fourth planetary gear system 4040 is fixedly connected with the four-wheel drive system housing 6003, so the rotational speed n _S4 of the sun gear 4041 of the fourth planetary gear system 4040 ≠0, that is, the TV control of the spline connection with the sun gear 4041 The hollow inner rotor of the motor 5001 will produce a slight idling. However, because the idling speed is extremely small, the energy consumption generated by it is also extremely small, which can basically be ignored. In addition, the frequency and time of the general turning process are relatively less than those of straight-line driving conditions. For the same reason, the rotational speed of the TV control motor 5001 will quickly return to 0, and idling will no longer occur. Therefore, the economy of the whole vehicle will not be affected.

When the turning TV control motor 5001 is not activated, although there is a certain speed difference between the front and rear axles, the torque distribution relationship of the full-range active distribution of inter-axle torque is the same as that of the straight-line driving TV control motor 5001. The working conditions without starting are exactly the same, that is, And T _front > T _rear , at this time the front axle is still the main driving axle. The flow of torque distribution at this time is shown in Fig. 2 .

(3) The TV controls the motor 5001 to start when traveling straight.

When the car is running, if the axle load of the car moves forward, or the adhesion coefficient between the rear axle drive wheel and the ground is small, the rear axle drive wheel may slip due to excessive torque, and the front axle drive wheel may slip due to torque. Insufficient and unable to give full play to the adhesion between the ground and the phenomenon. At this time, in order to improve the power and passability of the vehicle, it is necessary to increase the driving torque of the front axle 6001 and reduce the driving torque of the rear axle 5002 while keeping the total driving torque unchanged. The drive torque distributed by the center differential 2000 to the rear axle 5002 of the vehicle is partially directed to the front axle 6001 of the vehicle. On the contrary, if the axle load moves backward due to the acceleration of the vehicle, or the adhesion coefficient between the front axle drive wheel and the ground is small, which may cause the front axle drive wheel to slip due to excessive torque, at this time, in order to improve the dynamic performance of the vehicle, and passability, it is also necessary to increase the driving torque of the rear axle 5002 and reduce the driving torque of the front axle 6001 while keeping the total driving torque unchanged, that is, to distribute the powertrain to the The drive torque of the front axle 6001 of the vehicle is partly directed to the rear axle 5002 of the vehicle.

In any state, the torque input by the power input shaft 5003 is always distributed to the front axle 6001 and the rear axle 5002 in a certain proportion through the central differential 2000, namely If it is necessary to realize the directional distribution of the torque between the front and rear axles according to the requirements of the above working conditions, it needs to be completed by the TV control motor 5001 at this time. Now take the vehicle axle load moving forward, or the working condition requirements of the rear axle driving wheel and the ground with a small adhesion coefficient to be analyzed as an example, to illustrate the full-time four-wheel drive system of the present invention with the active distribution of inter-axle torque in the straight line of the vehicle. The principle of torque-oriented distribution between the front and rear axles while driving.

When the axle load of the vehicle moves forward, or the adhesion coefficient between the driving wheel of the rear axle and the ground is small, part of the driving torque of the rear axle 5002 of the automobile should be directionally distributed to the front axle 6001 of the automobile. At this time, the electric signal controls the TV control motor 5001 to output a forward torque T (T is a positive value), and then the torque T of the sun gear 4041 of the fourth planetary gear train 4040 spline-connected to the hollow inner rotor of the TV control motor 5001 _S4 =T, according to the single planet row torque formula, the torque T _H4 of the planet carrier 4044 of the fourth planetary gear train 4040 =-(k ₄ +1)T (wherein k ₄ is the planet of the fourth planetary gear train 4040 row characteristic parameters), then the torque output from the planetary carrier 4044 of the fourth planetary gear train 4040 to the ring gear 3033 of the third planetary gear train 3030 is T _R3 =(k ₄ +1)T. Assuming that the planetary row characteristic parameters of the second planetary gear system 3020 and the third planetary gear system 3030 are both k, that is, k ₂ =k ₃ =k, then according to the single planetary gear torque formula, the sun of the third planetary gear system 3030 can be obtained The torques of the wheel 3031 and the planet carrier 3034 are respectively Therefore, the torque output by the sun gear 3031 in the third planetary gear train 3030 is Then the torque increment input to the rear axle 5002 is The torque output by the planet carrier 3034 is Then the input torque of the planet carrier 3024 in the second planetary gear train 3020 is According to the single planet row torque formula, the torque of the sun gear 3021 of the second planetary gear train 3020 is obtained Then the torque output by the sun gear 3021 is Then the torque input to the planetary carrier 2014 of the first planetary gear train 2010 is According to the single planet row torque formula, the torques of the sun gear 2011 and the ring gear 2013 of the first planetary gear train 2010 are respectively Then the output torque of the sun gear 2011 in the first planetary gear train 2010 is Then the torque increment input to the rear axle 5002 is Therefore, the total torque increment T _after the input to the rear axle 5002 is input to the torque increment T of the rear axle 5002 by the sun gear ₃₀₃₁ of the third planetary gear train 3030, and the sun gear of the first planetary gear train 2010 2011 is the sum of the two parts _after the torque increment T input to the rear axle 5002, namely The output torque of the ring gear 2013 is The torque increment input to the input sprocket 1000 is then Therefore, the torque increment transmitted to the front axle 6001 is It can be seen that the torque increment of the TV control motor 5001 input to the front axle and the rear axle through the TV control motor deceleration mechanism 4000, the double planetary row TV coupling mechanism 3000 and the central differential 2000 is reversed (the torque increment The positive and negative signs of the quantity are shown in the positive and negative signs marked on the torque distribution flow from the TV control motor 5001 to the front and rear axles as shown in Figure 3), that is, T _front '=-T _back '. After the above torque increment is synthesized with the torque distributed to the front and rear axles by the powertrain through the central differential 2000, the driving torque of the front axle 6001 at this time can be obtained as The driving torque of the rear axle 5002 becomes It can be seen that, compared with the TV control motor 5001 in the non-working state, the driving torque of the front axle 6001 increases at this time, and the driving torque of the rear axle 5002 decreases. Axis 5002 is assigned to the orientation transfer of front axis 6001. The flow of torque distribution at this time is shown in Fig. 3 . In extreme cases, control the TV to control the output torque of the motor 5001 All the torque distributed to the rear axle 5002 by the powertrain via the central differential 2000 can be transferred to the front axle 6001 to realize single-axle drive, that is, the front drive state.

In the same way, it can be obtained that when the axle load of the vehicle moves backward, or the adhesion coefficient between the driving wheel of the front axle and the ground is small, the driving torque of the front axle 6001 of the vehicle should be distributed to the rear axle 5002 of the vehicle in a directional manner. At this time, the electric signal controls the TV control motor 5001 to output a negative torque, and through the TV control motor deceleration mechanism 4000, the double planetary row TV coupling mechanism 3000, the central differential 2000, and the input sprocket 1000, a negative torque is finally distributed to the front axle 6001. To increase the torque, assign a positive torque increase to the rear axle 5002, and the two are equal in size, that is, the driving torque of the front axle 6001 of the vehicle can be reduced without changing the total driving torque , the driving torque of the rear axle 5002 increases. The working process under this working condition is similar to the working process when the axle load of the vehicle moves forward, or when the adhesion coefficient between the rear axle drive wheel and the ground is small, and will not be repeated here.

(4) The TV control motor 5001 starts when turning.

In this working condition, the relationship between the rotation speed of the full-time four-wheel drive system and the torque distribution of the powertrain distributed to the front axle 6001 and the rear axle 5002 in a fixed ratio through the center differential 2000 The relationship is the same as that of the turning TV control motor 5001 not starting, so it will not be repeated here. The output torque of the TV control motor 5001 is the same as the working condition of the straight-line running TV control motor 5001 for the equal and opposite torque increments of the front and rear axle torques, so it will not be repeated here. The flow of torque distribution at this time is shown in Fig. 3 .

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (9)

1. A full-time four-wheel drive system with active distribution of inter-axle torque in the whole area, characterized in that it includes: power input shaft; front axle; rear axle; a first planetary gear train comprising a first sun gear, a first planet gear, a first planet carrier and a first ring gear; Wherein, the first planet carrier is fixedly connected with the power input shaft, and it is provided with a hollow shaft, and the hollow shaft of the first planet carrier is sleeved on the rear axle; the first sun gear and the The rear shaft is fixedly connected, the first inner ring gear is provided with a hollow shaft, and the hollow shaft of the first inner ring gear is sleeved on the power input shaft; a second planetary gear train comprising a second sun gear, a second planet gear, a second planet carrier and a second ring gear; Wherein, the second sun gear is fixedly connected to the hollow shaft of the first planet carrier, and the second ring gear is fixedly connected to the four-wheel drive system housing; a third planetary gear train, which includes a third sun gear, a third planet gear, a third planet carrier and a third ring gear; Wherein, the third sun gear is fixedly connected to the rear axle; the third planet carrier is fixedly connected to the second planet carrier; Wherein, the second planetary gear set and the third planetary gear set have the same planetary row characteristic parameters and planetary row types; TV control motor, which is provided with a hollow output shaft, the hollow output shaft is sleeved on the rear axle, and the hollow output shaft is connected with the third ring gear through a reduction mechanism; an input sprocket, the center of which is fixedly mounted on the hollow shaft of the first inner ring gear; an output sprocket fixedly connected to the front axle; Wherein, the input sprocket and the output sprocket perform power transmission through a transmission chain. 2. The full-time four-wheel drive system according to claim 1, wherein the full-time active distribution of inter-axle torque is characterized in that the reduction mechanism includes a fourth planetary gear train, which includes a fourth sun gear, a fourth planetary gear, a fourth Four-planet carrier and fourth ring gear; Wherein, the fourth sun gear is fixedly connected to the hollow output shaft; the fourth planet carrier is fixedly connected to the third ring gear; the fourth ring gear is fixed to the housing of the four-wheel drive system connect. 3 . The full-time four-wheel drive system according to claim 1 , wherein the transmission ratio between the input sprocket and the output sprocket is 1. 4. The full-time four-wheel drive system with global active distribution of inter-axle torque according to claim 1, characterized in that, the first planetary carrier is a detachable planetary carrier, which can be disassembled into several parts. Each part can be carried out separately, and then each part is assembled and fixedly connected as a whole, so that the first sun gear is wrapped inside it. 5. The full-time four-wheel drive system according to claim 4, characterized in that the hollow shaft of the first planetary carrier is connected to the rear axle through a bearing, and the first The hollow shaft of the inner ring gear is connected with the power input shaft through a bearing. 6. The full-time four-wheel drive system according to claim 1, characterized in that the TV control motor is a hollow-shaft inner rotor motor. 7 . The full-time four-wheel drive system according to claim 6 , wherein the hollow output shaft is connected to the rear shaft through a bearing. 8 . The full-time four-wheel drive system with global active distribution of inter-axle torque according to claim 7 , wherein the stator and housing of the TV control motor are fixedly connected to the four-wheel drive system housing. 9 . The full-time four-wheel drive system according to claim 8 , characterized in that, the hollow output shaft of the TV control motor is connected to the central hole of the fourth sun gear through a spline.