JPS6320228A - Four wheel drive device - Google Patents

Abstract

PURPOSE:To improve maneuverability and driveability by arranging a multi-plate clutch between a rear wheel side drive shaft and a planetary gear device so that different torque distributions can be selected. CONSTITUTION:A multi-plate clutch 8 is arranged between a rear wheel side drive shaft 4 and a planetary gear device 7 via a gear mechanism. When this clutch 8 becomes a disengaged condition, a drive torque from a transmission is transmitted to both front wheels and rear wheels respectively via the planetary gear device 7. The distribution of the drive torque during driving in this case becomes such that a front torque TF is greater than a rear torque TR according to a gear ratio of a gear 7a to a gear 7d. When the clutch 8 is engaged on the other hand, the drive shaft 4 is directly connected to a ring gear of the planetary gear device 7 and it becomes TF=TR. Accordingly, the torque distribution can be continuously changed by continuously changing hydraulic pressures to the clutch 8. As a result, maneuverability and driveability can be improved.

Description

【発明の詳細な説明】[Detailed description of the invention]

［産業上の利用分野］ この発明は、センターデフとしてプラネタリギヤ装置を
備えるフルタイム式４輪駆動車において、前、後輪の駆
動トルク配分を任意に制御して、操縦性、安定性および
走行性能を、目的または好みに応じて変化させることが
可能なトルク配分制御装置に関する。 ［従来の技術］ 従来、センターデフ付の４輪駆動車に関しては、例えば
特開昭５５−７２４２０号公報に示されるように、レン
ターデフ装置にディファレンシャルギヤを用い、その作
動制限用としてセンターデフ装置をロックするドッグク
ラッチを設（づたものがある。[Industrial Field of Application] The present invention is a full-time four-wheel drive vehicle equipped with a planetary gear device as a center differential, by arbitrarily controlling drive torque distribution between the front and rear wheels to improve maneuverability, stability, and driving performance. The present invention relates to a torque distribution control device that can change the torque distribution according to purpose or preference. [Prior Art] Conventionally, with respect to four-wheel drive vehicles equipped with a center differential, a differential gear is used for a rental differential device, and the center differential device is used to limit the operation of the differential gear, as shown in Japanese Patent Laid-Open No. 55-72420, for example. Some are equipped with a locking dog clutch.

【発明が解決しようとする問題点１ ところで、上記先行技術の構成のものにあっては、セン
ターデフ装置のディフｉ’　Ｉノンシャルギへ７は機構
上２つのサイドギヤの径が同一になっているため、前、
後輪のトルク配分ＧＪ常に略等分になる。従って、その
トルク配分を積極的に変化させることはできなかった。 またドッグクラッチは、前、後輪の一方が空転した場合
の緊＠脱出用として、デイファレンシャルギψを一体的
にロックするデフロック機能を右づるにすぎなかった、
１ここＣ４輪駆動車で・は、前、１ν輪のトルク配分を
各種走行条件に基づいて変化させると、走行性能以外に
旋回性、安定性などの操縦安定性も向上させ得ることが
知られている。そこでセンターデフ付のフルタイム式４
輪駆動車においても、トルり配分を積極的に制御して、
操縦性、安定性および走行性能の向上を図ることが望ま
れている。 この発明は、このような点に鑑みてなされたもので、積
極的に前、後輪のトルク配分を変えて、操縦性、安定性
および走行性能を、目的または好みに応じて変化させる
ことができる４輪駆動装置を提供することを目的とする
。 【問題点を解決するための手段】 上記した目的を達成するため、この発明は、センターデ
フとしてプラネタリギヤ装置を用いた４輪駆動車におい
て、後輪側駆動軸と上記プラネタリギヤ装置との間にギ
ヤ機構を介して油圧式多板クラッチを設け、リヤトルク
がフロントトルクよりも小さい状態と、両トルクがほぼ
等しい状態とを選択できるようにしたものである。 【作　　　用１ 上記構成に基づき、油圧式多板クラッチがオフの状態で
は、トランスミッションからの駆動トルクはセンターデ
フとしてのプラネタリギヤ装置を介して前、後輪へそれ
ぞれ伝達され、その駆動力配分は、フロントトルクＴＦ
がリヤトルクＴＲよりも大きな走行状態（ＴＦ　〕・Ｔ
Ｒ）となる。一方、油圧式多板クラッチに油圧を加えて
オンとした状態では、後輪側駆動軸とプラネタリギヤ装
置のリングギヤとは直結され、前、後輪の駆動力配分は
、ＴＦ　４ＴＲとなる。この場合、油圧式多板クラッチ
への油圧を連続的に変化させれば、トルク配分を連続的
に変化させることができ、操縦性、安定性および走行性
能を、目的または好みに応じて選択することが可能とな
る。 【実　施　例１ 以下、この発明の一実施例を図面に基づいて説明する。 図において、符号１はトランスミッションケース、２は
トランスミッションからの中空状の出力軸、３は前輪側
駆動軸で、出力軸２の中空部内に軸受１ａ、１ｂを介し
て軸承されている。４は後輪側駆動軸で、軸受１ｃ、　
１ｄに軸承されている。 ５はプロペラ軸、ＧはりＡ７デフ、７はセンターデフで
あるプラネタリギヤ装置で、サンギヤ７ａ、１ヤリヤ７
１）に軸支された複数個の遊星ビニオン７Ｃおよびリン
グギヤ７ｄからなり、キャリヤ７ｂは出力軸２に直結さ
れている。８は油圧式多板クラッチで、後輪側駆動軸４
に固着されたドラム８ａとクラッチハブ８ｂとからなる
。９はサンギヤ７ａと一体の第１歯車、１０は後輪側駆
動軸４に固着された第２歯車で、第１ｍ車９と噛合う。 １１はキャリヤ７ｂに固着された第３歯車で、第１歯車
９と同径である。１２はクラッチハブ８ｂと一体の第４
６１ｉＩ車である。１３は油圧ポンプ、１４は制御バル
ブ、１５はトルク配分制御回路である。 次に、このように構成されたトルク配分制御装置の動作
について説明する。先ず、トルク配分制御回路１５から
の信号で油圧ポンプ１３を駆動して油圧Ｐａを発生させ
るが、制御バルブ１４にオフ信号を与えてその出力油圧
Ｐを略零にすると、油圧が印加されないので油圧式多板
クラッチ８はオフ状態となる。この状態では、トランス
ミッションからの出力軸２の駆動力Ｔは、キャリヤ７ｂ
を介して遊星ビニオン７Ｇを、サンギヤ７ａとリングギ
ヤ７ｄとの間でそれぞれ噛合いながら転動させ、小径の
サンギャ７ａと大径のリングギヤ７ｄとのギヤ比により
、前輪側駆動軸３の駆動トルクＴＦと第１歯車９゜第２
＃ｌ車１０を介して伝達される後輪側駆動軸４の駆動ト
ルクＴＲとの比は、Ｔｐ　＞ＴＲとなり、前輪寄りの走
行状態となり、高速安定性重視となる。 一方、トルク配分制御回路１５からのオフ信号で制御バ
ルブ１４から油圧Ｐを油圧式多板クラッチ８に印加する
と、クラッチハブ８ｂはドラム８ａに接触し、遊星ビニ
オン７ｃ、サンギヤ７ａ、第１歯車９．第２歯車１０．
後輪側駆動軸４を介するドラム８ａへのトルクと、第３
歯車１１．第２歯車１０を介してのクラッチハブ８ｂ経
由のトルク、即ちクラップ−トルクＴＣにより、後輪側
の駆動トルクは（ＴＲ＋Ｔｃ　）に、前輪側の駆動トル
クは（ＴＦ　−Ｔｃ　）になり、油圧を高めることによ
り（ＴＲ−１−ＴＣ）　ｓ　（ＴＦ−Ｔｃ　）となる。 このように前、後輪のトルク配分が略等しい４輪駆動状
態では、走破性を最大限に発揮することができる。この
場合、油圧式多板クラッチ８へ印加する油圧Ｐを連続的
に変化させれば、トルク配分も連続的に変化するので、
任意の配分比を選択づることができると共に、前輪駆動
寄りの走行状態から等トルク配分の４輪駆動への切換え
に伴うシコックを緩和することができる。 また、油圧式多板クラッチ８を使ってオフまたはオン制
御するので、従来のドッグクラッチのような作動の不円
滑や遅れなどの現象は発生せず、ボタン式制陣も可能と
なる。 さらに、油圧式多板クラッチ８に最大油圧を印加して前
、後輪側駆動軸３，４を直結した状態で急制動をかけた
場合でも、制御バルブ１４の切換えで油圧Ｐを瞬間的に
下げて油圧式多板クラッチ８をオフし、従来のドッグク
ラッチでは不確実であったが、直ちに向結状態を解放し
て車両の安定性を確保することができる。 なお、上記実施例では、油圧式多板クラッチ８を用いて
前、後輪のトルク配分を制御するようにしていたが、油
圧式に限定するものではなく、電磁クラッチまたは電動
クラッチあるいは空気圧式多板クラッチを用いても、同
様な効果を行ることができる。 【発明の効果） 以上の説明から明らかなように、この発明の４輪駆動装
置によれば、センターデフとしてのプラネタリギヤ装置
に油圧式多板クラッチ〜を付加して、前、後輪のトルク
配分を積極的に変えるようにしたので、操縦性、安定性
および発進性・走行性を、目的または好みに応じて変化
させることができる。 また制動時には、油圧を瞬間的に下げて油圧式多板クラ
ッチをオフすることができるので、車両の安定性を確保
できる。[Problem to be Solved by the Invention 1] By the way, in the configuration of the prior art described above, the diameter of the two side gears of the center differential device is the same due to the mechanism. ,Before,
Torque distribution GJ to the rear wheels is always approximately equal. Therefore, it was not possible to actively change the torque distribution. In addition, the dog clutch was simply a right-handed differential lock function that integrally locked the differential gear ψ in case one of the front or rear wheels spun.
In 1C four-wheel drive vehicles, it is known that by changing the torque distribution between the front and 1ν wheels based on various driving conditions, it is possible to improve not only driving performance but also handling stability such as turning performance and stability. ing. Therefore, full-time type 4 with center differential
Even in wheel drive vehicles, torque distribution is actively controlled,
It is desired to improve maneuverability, stability, and running performance. This invention was made in view of these points, and it is possible to actively change the torque distribution between the front and rear wheels to change maneuverability, stability, and driving performance according to the purpose or preference. The purpose is to provide a four-wheel drive device that can. [Means for Solving the Problems] In order to achieve the above object, the present invention provides a four-wheel drive vehicle using a planetary gear device as a center differential, in which a gear is provided between the rear wheel drive shaft and the planetary gear device. A hydraulic multi-disc clutch is provided via the mechanism, allowing selection between a state in which the rear torque is smaller than the front torque and a state in which both torques are approximately equal. [Operation 1] Based on the above configuration, when the hydraulic multi-plate clutch is off, the driving torque from the transmission is transmitted to the front and rear wheels via the planetary gear device as a center differential, and the driving force distribution is as follows: front torque TF
is a driving condition where the rear torque TR is larger than the rear torque TR (TF )・T
R). On the other hand, when the hydraulic multi-plate clutch is turned on by applying hydraulic pressure, the rear wheel drive shaft and the ring gear of the planetary gear device are directly connected, and the driving force distribution between the front and rear wheels becomes TF 4TR. In this case, by continuously changing the oil pressure to the hydraulic multi-disc clutch, the torque distribution can be changed continuously, allowing you to select maneuverability, stability, and driving performance according to your purpose or preference. becomes possible. [Embodiment 1] An embodiment of the present invention will be described below based on the drawings. In the figure, numeral 1 is a transmission case, 2 is a hollow output shaft from the transmission, and 3 is a front wheel drive shaft, which is supported within the hollow portion of the output shaft 2 via bearings 1a and 1b. 4 is the rear wheel side drive shaft, bearing 1c,
1d. 5 is a propeller shaft, G beam A7 differential, 7 is a planetary gear device which is a center differential, sun gear 7a, 1 gear rear 7
1), and a carrier 7b is directly connected to the output shaft 2. 8 is a hydraulic multi-plate clutch, which is connected to the rear wheel drive shaft 4.
It consists of a drum 8a and a clutch hub 8b, which are fixed to the drum 8a and the clutch hub 8b. Reference numeral 9 indicates a first gear integral with the sun gear 7a, and reference numeral 10 indicates a second gear fixed to the rear drive shaft 4, which meshes with the first m-wheel 9. A third gear 11 is fixed to the carrier 7b and has the same diameter as the first gear 9. 12 is a fourth unit integrated with the clutch hub 8b.
It is a 61iI car. 13 is a hydraulic pump, 14 is a control valve, and 15 is a torque distribution control circuit. Next, the operation of the torque distribution control device configured as described above will be explained. First, the hydraulic pump 13 is driven by a signal from the torque distribution control circuit 15 to generate hydraulic pressure Pa. However, when an off signal is given to the control valve 14 to make its output hydraulic pressure P approximately zero, no hydraulic pressure is applied, so the hydraulic pressure The multi-disc clutch 8 is turned off. In this state, the driving force T of the output shaft 2 from the transmission is transmitted to the carrier 7b.
The planetary pinion 7G is caused to roll while meshing with the sun gear 7a and the ring gear 7d, respectively, and the drive torque TF of the front wheel drive shaft 3 is controlled by the gear ratio of the small diameter sun gear 7a and the large diameter ring gear 7d. and 1st gear 9° 2nd
The ratio of the drive torque TR of the rear wheel drive shaft 4 transmitted through the #l vehicle 10 is Tp>TR, and the vehicle is driven closer to the front wheels, placing emphasis on high-speed stability. On the other hand, when hydraulic pressure P is applied from the control valve 14 to the hydraulic multi-disc clutch 8 in response to an off signal from the torque distribution control circuit 15, the clutch hub 8b contacts the drum 8a, and the planetary pinion 7c, sun gear 7a, and first gear 9 ．． Second gear 10.
Torque to the drum 8a via the rear wheel side drive shaft 4 and the third
Gear 11. Due to the torque transmitted via the clutch hub 8b via the second gear 10, that is, the clamp torque TC, the drive torque on the rear wheel side becomes (TR + Tc) and the drive torque on the front wheel side becomes (TF - Tc), which increases the hydraulic pressure. By increasing it, (TR-1-TC) s (TF-Tc) is obtained. In this four-wheel drive state where the torque distribution between the front and rear wheels is approximately equal, it is possible to maximize the running performance. In this case, if the hydraulic pressure P applied to the hydraulic multi-disc clutch 8 is continuously changed, the torque distribution will also be continuously changed.
It is possible to select an arbitrary distribution ratio, and it is also possible to alleviate the shock caused by switching from a front-wheel drive driving state to four-wheel drive with equal torque distribution. In addition, since the hydraulic multi-plate clutch 8 is used for off/on control, phenomena such as unsmooth operation or delays that occur with conventional dog clutches do not occur, and button-type control is also possible. Furthermore, even if the maximum oil pressure is applied to the hydraulic multi-disc clutch 8 and sudden braking is applied with the front and rear drive shafts 3 and 4 directly connected, the oil pressure P can be changed instantaneously by switching the control valve 14. By lowering the hydraulic multi-plate clutch 8, the hydraulic multi-disc clutch 8 is turned off, and, unlike the conventional dog clutch, which was uncertain, it is possible to immediately release the cross-coupled state and ensure the stability of the vehicle. In the above embodiment, the hydraulic multi-disc clutch 8 was used to control the torque distribution between the front and rear wheels, but it is not limited to the hydraulic type, and an electromagnetic clutch, an electric clutch, or a pneumatic multi-disc clutch may be used. A similar effect can be achieved by using a plate clutch. [Effects of the Invention] As is clear from the above description, according to the four-wheel drive device of the present invention, a hydraulic multi-disc clutch is added to the planetary gear device as a center differential to distribute torque between the front and rear wheels. Since the characteristics of the vehicle are actively changed, the maneuverability, stability, starting performance, and running performance can be changed according to the purpose or preference. Furthermore, during braking, the hydraulic pressure can be instantly lowered and the hydraulic multi-disc clutch can be turned off, ensuring vehicle stability.

【図面の簡単な説明】[Brief explanation of drawings]

図面はこの発明の一実施例を示す４輪駆動装置のスプル
１〜ン図である。 ２・・・トランスミッションからの出力軸、３・・・前
輪側駆動軸、４・・・後輪側駆動軸、７・・・プラネタ
リギヤ装置、８・・・油圧式多板クラッチ、９〜１２・
・・歯車、１４・・・制御バルブ、１５・・・トルク配
分制御回路。The drawings are sprue diagrams 1 to 1 of a four-wheel drive device showing an embodiment of the present invention. 2... Output shaft from transmission, 3... Front wheel side drive shaft, 4... Rear wheel side drive shaft, 7... Planetary gear device, 8... Hydraulic multi-plate clutch, 9-12.
...Gear, 14...Control valve, 15...Torque distribution control circuit.

Claims (1)

【特許請求の範囲】 　センターデフとしてプラネタリギヤ装置を用いた４輪
駆動車において、 後輪側駆動軸と上記プラネタリギヤ装置との間にギヤ機
構を介して油圧式多板クラッチを設け、リヤトルクがフ
ロントトルクよりも小さい状態と、両トルクがほぼ等し
い状態とを選択できるようにしたことを特徴とする４輪
駆動装置。[Claims] In a four-wheel drive vehicle using a planetary gear device as a center differential, a hydraulic multi-plate clutch is provided via a gear mechanism between the rear wheel drive shaft and the planetary gear device, so that the rear torque is equal to the front torque. A four-wheel drive device characterized in that it is possible to select between a state in which the torques are smaller than 1 and a state in which both torques are substantially equal.