JPS6311423A - Power transmission device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the reduction of transmission torque and improve durability by specifying the shape of a variable orifice so that the opening degree of the variable orifice increases according to the increase of the differential revolution between a plurality of driving shafts, thus eliminating the state where the differential revolution is large, in a short time. CONSTITUTION:A power transmission device 7 is equipped with a hydraulic clutch 14 for connecting a plurality of driving shafts 8 and 11, viscous coupling 33 for generating the torque corresponding to the differential revolution between the both driving shafts 8 and 11, variable orifice 34 which varies the opening degree according to the torque, and a hydraulic source 30 for supplying the working hydraulic pressure to the hydraulic clutch 14. In this case, the shape on the sectional surface in the direction crossing at right angles with the axis line of a slit 36a in one axial direction of the variable orifice 34 is formed so that the dimension in the radial direction increases with the separation in the peripheral direction from a slit 35a in the other axial direction. As the differential revolution between the both driving shafts 8 and 11 increases, the opening degree of the variable orifice 34 increases.

Description

【発明の詳細な説明】 （産業上の利用分野） この発明は、車両用動力伝達装置に関するものであり、
特には、四輪駆動車の前輪用駆動軸と後輪用駆動軸との
間で動力伝達を行う動力伝達装置や差動装置を介して連
結する左右の駆動軸間で動力伝達を行なう動力伝達装置
に関するものである。[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a power transmission device for a vehicle,
In particular, power transmission devices that transmit power between the front wheel drive shaft and rear wheel drive shaft of four-wheel drive vehicles, and power transmission devices that transmit power between the left and right drive shafts connected via a differential device. It is related to the device.

（従来の技術） 従来のかかる動力伝達装置としては、例えば、ビスカス
・カップリング（株式会社二玄社昭和６１年４月１日発
行のカーグラフィック１９８６゜５月号中第８５頁〜第
９１頁参照）が知られている。(Prior Art) As a conventional power transmission device, for example, a viscous coupling (see pages 85 to 91 of the May issue of Car Graphic 1986, published by Nigensha Co., Ltd. on April 1, 1986) It has been known.

ビスカス・カップリングは、二軸にそれぞれ結合した多
数の円板を交互に配置して、それらの円板の間に粘性流
体を介在させ、粘性流体を介して円板間、ひいては、二
軸間で、それらの軸の間の相対回転に応じた動力伝達を
行うように構成したものであり、このことから、例えば
、後輪用駆動軸にエンジンの駆動力を直接的に伝達する
型式の四輪駆動車（以下、ＦＲベースの四輪駆動車と呼
ぶ）の、前輪用駆動軸と後輪用駆動軸との間に介装され
たビスカス・カップリングは、第８図に示Ｊように、そ
れらの駆動軸の間の差動回転の増加、すなわち、前輪用
駆動軸の回転数（以下、ＮＦと呼び、前進時の回転方向
への回転を正とする）と、後輪用駆動軸の回転数（以下
、ＮＲと呼び、前進時の回転方向への回転を正とする）
との差ΔＮ（−Ｎｐ　−ＮＦ　）の増加に応じ、その差
動回転の方向のトルク下を増加さゼて伝達すべく機能す
る。A viscous coupling consists of alternately arranging a large number of disks each connected to two axes, and interposing a viscous fluid between the disks. It is configured to transmit power according to the relative rotation between these axes, and for this reason, for example, a type of four-wheel drive that transmits the driving force of the engine directly to the drive shaft for the rear wheels. The viscous coupling installed between the front wheel drive shaft and the rear wheel drive shaft of a vehicle (hereinafter referred to as an FR-based four-wheel drive vehicle) is An increase in the differential rotation between the drive shafts of number (hereinafter referred to as NR, rotation in the direction of rotation when moving forward is considered positive)
In response to an increase in the difference ΔN (-Np - NF) between the differential rotation direction and the differential rotation direction, the torque in the direction of the differential rotation is increased.

従って、このビスカス・カップリングを用いた四輪駆動
車によれば、後輪にスリップが生じた場合に、後輪用駆
動軸と前輪用駆動軸との間の差動回転に基づき、後輪用
駆動軸から前輪用駆動軸に駆動力を伝達して、車両の駆
動力を確保することができる。Therefore, according to a four-wheel drive vehicle using this viscous coupling, when slip occurs in the rear wheels, the rear wheels are activated based on the differential rotation between the rear wheel drive shaft and the front wheel drive shaft. The driving force of the vehicle can be ensured by transmitting the driving force from the front wheel drive shaft to the front wheel drive shaft.

（発明が解決しようとする問題点） しかしながら、このビスカス・カップリングにあっては
、回転数差ΔＮの増加に対応する伝達トルク下の増加の
割り合いが、ΔＮの増加に従って減少する特性、すなわ
ち、王の、ΔＮに対する二階微分値が負（ｄ　２Ｔ／ｄ
　　（ΔＮ）２〈０）となる特性を有することから、上
述した四輪駆動車を荒地や泥障地にて走行させ、あるい
はスタック状態から脱出させる場合の如く、回転数差Δ
Ｎが比較的大きくなる（特に、ΔＮ　＞　１１００ｒｐ
となる）場合には、ΔＮが増加しても伝達トルクＴがそ
れほど増加せず、このことのゆえに、前輪用駆動軸に十
分大きな駆動力を伝達できずして、ΔＮが大きい状態を
持続させる傾向があり、従って、粘性流体が高温となっ
て、伝達トルクＴの低下や、粘性流体の劣化を引き起こ
すという問題があった。(Problem to be Solved by the Invention) However, this viscous coupling has a characteristic that the rate of increase in the transmitted torque corresponding to an increase in the rotational speed difference ΔN decreases as ΔN increases. , King's second derivative with respect to ΔN is negative (d 2T/d
(ΔN)2<0), so when the above-mentioned four-wheel drive vehicle is driven on rough terrain or muddy terrain, or when escaping from a stuck state, the rotational speed difference Δ
N becomes relatively large (especially ΔN > 1100rp
), even if ΔN increases, the transmitted torque T does not increase that much, and because of this, a sufficiently large driving force cannot be transmitted to the front wheel drive shaft, and ΔN continues to be large. Therefore, there is a problem that the viscous fluid becomes high temperature, causing a decrease in the transmission torque T and deterioration of the viscous fluid.

さらに、このビスカス・カップリングにあっては、上述
した粘性流体の高温化が、円板の熱変形による相互接触
、いわゆるハンプ現象を生じさせて、耐久性を低下させ
ることがあるという他の問題もあった。Furthermore, another problem with this viscous coupling is that the above-mentioned high temperature of the viscous fluid can cause mutual contact due to thermal deformation of the discs, a so-called hump phenomenon, which may reduce durability. There was also.

この発明は、差動回転が大きい状態をｙｒｉ時間で解消
することを可能として、上述した問題点を有利に解決し
た動力伝達装置を提供するものである。The present invention provides a power transmission device that advantageously solves the above-mentioned problems by making it possible to eliminate a state in which the differential rotation is large in yri time.

（問題点を解決するための手段） この発明の車両用動力伝達装置は、第１駆動軸と第２駆
動軸とを適宜に駆動結合する油圧クラッチと、前記第１
駆動軸と前記第２駆動軸との間の差Ｗｈ回転に応じたト
ルクを発生する粘性カップリングと、前記トルクに応じ
て開度変化する可変オリフィスと、前記可変オリフィス
を経て前記油圧クラッチに作動油圧を供給する油圧源と
を具え、前記第１駆動軸および前記第２駆動軸の間で、
前記差動回転に応じた動力伝達を行う動力伝達装置にお
いて、 前記可変オリフィスの形状を、前記差動回転の増加に対
応する前記可変オリフィスの開度の増加の割り合いが前
記差動回転の増加に応じて増加する形状とすることを特
徴とする。(Means for Solving the Problems) The vehicle power transmission device of the present invention includes a hydraulic clutch that drives and connects a first drive shaft and a second drive shaft as appropriate;
a viscous coupling that generates a torque according to the rotational difference Wh between the drive shaft and the second drive shaft; a variable orifice whose opening degree changes according to the torque; and a variable orifice that operates the hydraulic clutch through the variable orifice. a hydraulic source for supplying hydraulic pressure, between the first drive shaft and the second drive shaft,
In the power transmission device that transmits power according to the differential rotation, the shape of the variable orifice is such that the rate of increase in the opening degree of the variable orifice corresponding to the increase in the differential rotation is determined by the increase in the differential rotation. It is characterized by having a shape that increases according to.

（作　用） かかる装置にあっては、第１駆動軸と第２駆動軸との間
に差動回転が生ずると、これに応じて粘性ノ」ツブリン
グがトルクを生じ、このトルクに応じて、可変オリフィ
スが開度変化して、油圧源から油圧クラッチに供給する
作動油圧を変化させ、そして、この作動油圧の変化に応
じて、油圧クラッチが、第１駆動軸と第２駆動軸との間
での伝達トルクを変化させる。(Function) In such a device, when differential rotation occurs between the first drive shaft and the second drive shaft, the viscous ring generates torque, and in response to this torque, The variable orifice changes the opening degree to change the working oil pressure supplied from the hydraulic source to the hydraulic clutch, and in response to the change in the working oil pressure, the hydraulic clutch moves between the first drive shaft and the second drive shaft. Change the transmitted torque at .

しかもここでは可変オリフィスの、作動回転の増加に対
応するその開度の増加の割り合いが、差動回転の増加に
応じて増加するので、差動回転が増加する程、油圧クラ
ッチによる伝達トルクの増加率が上昇する。Moreover, here, the rate at which the opening degree of the variable orifice increases in response to an increase in operating rotation increases in accordance with an increase in differential rotation, so the more the differential rotation increases, the more the torque transmitted by the hydraulic clutch increases. Increase rate of increase.

従って、この装置によれば、第１駆動軸と第２駆動軸と
の間にスリップが生じた場合には、第１駆動軸と第２駆
動軸との間の差動回転に基づき、スリップの生じた方の
車軸に駆動力を伝達して車両の駆動力を確保することが
でき、さらには、差動回転が大きくなると、伝達トルク
を極めて大きなものとして、車両を充分なる駆動力で駆
動し、これによって差動回転が大きい状態を短時間で解
消し冑て、粘性カップリング内の粘性流体および油圧ク
ラッチの発熱を効果的に防止し、ひいては、伝達トルク
の低下を防止するとともに、耐久性を向上させることが
できる。Therefore, according to this device, when a slip occurs between the first drive shaft and the second drive shaft, the slip is eliminated based on the differential rotation between the first drive shaft and the second drive shaft. It is possible to secure the vehicle's driving force by transmitting the driving force to the generated axle, and furthermore, when the differential rotation becomes large, the transmitted torque is extremely large and the vehicle can be driven with sufficient driving force. This quickly resolves the situation where the differential rotation is large, effectively preventing the viscous fluid in the viscous coupling and the heat generation of the hydraulic clutch, which in turn prevents a decrease in transmission torque and improves durability. can be improved.

（実施例） 以下に、この発明の実施例を図面に基づき詳細に説明す
る。(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

第１図はこの発明の車両用動力伝達装置を四輪駆動車用
動力伝達装置として用いた場合の一実施例を示す断面図
であり、第２図は、この例の装置全３Ｍ用したＦＲベー
スの四輪駆動車の動力伝達経路を示す。FIG. 1 is a sectional view showing an embodiment of the vehicle power transmission device of the present invention used as a four-wheel drive vehicle power transmission device, and FIG. The power transmission path of the base four-wheel drive vehicle is shown.

第２図中１はエンジン、２は変速機、３は歯車装置をそ
れぞれ示し、ここでは、エンジン１の出力軸を変速１ｆ
ｔｌ１２の入力軸に、変速ｖｓ２の出力軸を歯車装置３
の後輪用出力軸４の一端部にそれぞれ駆動結合する。In Fig. 2, 1 is an engine, 2 is a transmission, and 3 is a gear device. Here, the output shaft of the engine 1 is shifted to 1f.
Connect the output shaft of shift vs2 to the input shaft of tl12 and gear device 3.
The drive shafts are each coupled to one end of the output shaft 4 for the rear wheels.

歯車装Ｍ３は、後輪用出力軸４と、この後輪用出力軸４
に歯車結合した、出力軸４と逆方向へそれと同速度で回
転する中間軸５と、この中間軸５と軸線方向へ整列する
前輪用出力軸６と、それらの軸５，６の間に介装した、
後述するこの例の動力伝達装置７とを具えてなり、ここ
では、その後輪用出力軸４の他端部に、後輪用駆動軸８
（第１駆動軸）および差動歯車装置９を介して左右後輪
１０、１０を駆動結合する一方、前輪用出力軸６に、前
輪用駆動軸１１（第２駆動軸）および差動歯車装置１２
を介して左右前輪１３．１３を駆動結合する。The gear system M3 includes a rear wheel output shaft 4 and a rear wheel output shaft 4.
An intermediate shaft 5 which is gear-coupled to the output shaft 4 and rotates at the same speed as the output shaft 4 in the opposite direction, a front wheel output shaft 6 which is aligned with the intermediate shaft 5 in the axial direction, and an intermediate shaft 5 interposed between the shafts 5 and 6. dressed,
Here, a rear wheel drive shaft 8 is connected to the other end of the rear wheel output shaft 4.
The left and right rear wheels 10, 10 are drive-coupled via a (first drive shaft) and a differential gear device 9, while a front wheel drive shaft 11 (second drive shaft) and a differential gear device are connected to the front wheel output shaft 6. 12
The left and right front wheels 13.13 are drive-coupled via.

従って、ここでは、後輪用駆動軸８と前輪用駆動軸１１
との間の差動回転の増加に応じて、中間軸５と前輪用出
力軸６との間の相対回転が増加し、かつ、駆動軸８．１
１間の差動回転の方向の変化に応じて、軸５，６間の相
対回転の方向も変化する。Therefore, here, the rear wheel drive shaft 8 and the front wheel drive shaft 11 are
According to an increase in the differential rotation between the intermediate shaft 5 and the front wheel output shaft 6, the relative rotation between the intermediate shaft 5 and the front wheel output shaft 6 increases.
According to a change in the direction of differential rotation between shafts 5 and 1, the direction of relative rotation between shafts 5 and 6 also changes.

これらの軸５，６間に位置する動力伝達装置７は、第１
図に示すように、軸５，６間、ひいては、駆動軸８．１
１間を駆動結合可能な油圧クラッチ１４を有しており、
この油圧クラッチ１４は、クラッチドラム１５を、中間
軸５に結合するとともに前輪用出力軸６に回転自在に支
持して具える。A power transmission device 7 located between these shafts 5 and 6 is a first
As shown in the figure, between the shafts 5 and 6, and therefore the drive shaft 8.1
It has a hydraulic clutch 14 that can drive and connect between
The hydraulic clutch 14 includes a clutch drum 15 coupled to the intermediate shaft 5 and rotatably supported by the front wheel output shaft 6.

クラッチドラム１５内にはクラッチハブ１６を配設し、
ここでは、このクラッチハブ１６を前輪用出力軸６に一
体的に結合する。そして、クラッチドラム１５の外部筒
状部分１５ａとクラッチハブ１６の筒状部分１６ａとの
間には、外部筒状部分１５ａにスプライン結合したクラ
ッチプレート１７と、筒状部分１６ａにスプライン結合
したクラッチプレート１８とを数枚づつ交互に配置し、
また、クラッチドラム１５の外部筒状部分１５ａと内部
筒状部分１５ｂとの間には、クラッチプレート１７．１
８を相互に抑圧可能なピストン１９を摺動自在に嵌め合
わせる。A clutch hub 16 is disposed within the clutch drum 15,
Here, this clutch hub 16 is integrally coupled to the front wheel output shaft 6. Between the outer cylindrical portion 15a of the clutch drum 15 and the cylindrical portion 16a of the clutch hub 16, there are a clutch plate 17 spline-coupled to the outer cylindrical portion 15a, and a clutch plate spline-coupled to the cylindrical portion 16a. 18 and placed several sheets at a time alternately,
Further, between the outer cylindrical portion 15a and the inner cylindrical portion 15b of the clutch drum 15, a clutch plate 17.1 is provided.
8 and a piston 19 which can be mutually suppressed are slidably fitted together.

このピストン１９は、リターンスプリング２０によって
図では右方へ常時付勢されており、ピストン１９とクラ
ッチドラム１５との間に画成された油室２１内の作動油
圧が十分低い場合にはクラッチの締結を無くし、油室２
１内の作動油圧が上昇すると、リターンスプリング２０
に抗して図では左方へ移動し、クラッチプレート１７．
１８の相互の押圧をもたらすことにて、作動油圧の上昇
に応じて油圧クラッチ１４の締結力を増加させるべく機
能する。This piston 19 is always urged to the right in the figure by a return spring 20, and when the working oil pressure in an oil chamber 21 defined between the piston 19 and the clutch drum 15 is sufficiently low, the clutch is activated. Eliminate fastening, oil chamber 2
When the working oil pressure in 1 increases, the return spring 20
Clutch plate 17.
18, it functions to increase the engagement force of the hydraulic clutch 14 in accordance with the increase in the working oil pressure.

かかる油室２１内の作動油圧の制御のために、ここでは
、ピストン１９に、小径の貫通孔である固定オリフィス
２２を設けるとともに、油室２１を、内部筒状部分１５
ｂに設けた貫通孔２３、前輪用出力軸６に形成した外周
条溝２４および半径方向孔２５、前輪用出力軸６とその
内部に配置したトーションバー２６との間の環状通路２
７、そして、同じく前輪用出力軸６に形成した半径方向
孔２８および外周条溝２９を介して、油圧源３０に連通
させる。ここで、この油圧源３０は、オイルポンプ３１
および定圧弁３２からなり、条溝２９に一定油圧を供給
すべく機能する。In order to control the hydraulic pressure in the oil chamber 21, the piston 19 is provided with a fixed orifice 22, which is a small-diameter through hole, and the oil chamber 21 is connected to the inner cylindrical portion 15.
b, a through hole 23 provided in the front wheel output shaft 6, an outer circumferential groove 24 and a radial hole 25 formed in the front wheel output shaft 6, and an annular passage 2 between the front wheel output shaft 6 and the torsion bar 26 disposed therein.
7, and communicates with a hydraulic pressure source 30 via a radial hole 28 and an outer circumferential groove 29, which are also formed in the front wheel output shaft 6. Here, this hydraulic power source 30 is an oil pump 31
and a constant pressure valve 32, which functions to supply a constant hydraulic pressure to the grooves 29.

またここでは、トーションバー２６の一端部を前輪用出
力軸６に駆動結合する一方、他端部を、ラビリンス構造
の粘性カップリング３３を介してクラッチドラム１５、
従って中間軸５に駆動連結する。Further, here, one end of the torsion bar 26 is drive-coupled to the front wheel output shaft 6, while the other end is connected to the clutch drum 15 via a viscous coupling 33 having a labyrinth structure.
Therefore, it is drivingly connected to the intermediate shaft 5.

ここにおける粘性カップリング３３は、その内部に封入
された粘性油を介して、周知の作用により、中間軸５と
前輪用出力軸６との間の相対回転に応じたトルクを発生
させるものであり、粘性７Ｊツブリング３３が発生させ
た］ヘルツは、トーションバー２６に、上述の相対回転
に応じた捩れを生じさゼる。The viscous coupling 33 here generates torque in accordance with the relative rotation between the intermediate shaft 5 and the front wheel output shaft 6 through a well-known action via viscous oil sealed therein. , generated by the viscous 7J twisting 33] causes the torsion bar 26 to twist in accordance with the above-mentioned relative rotation.

尚、ここで、粘性カップリング３３は、相対回転がいず
れの方向であっても、その相対回転方向のトルクを発生
させ、従って、トーションバー２６は、相対回転の方向
に応じて、その方向へ捩じられる。Here, the viscous coupling 33 generates a torque in the direction of the relative rotation regardless of the direction of the relative rotation, and therefore the torsion bar 26 moves in that direction depending on the direction of the relative rotation. Twisted.

このトーションバー２６の捩れに基づいて、油室２１内
の作動油圧を制御すべく、ここではさらに、環状通路２
７内に、可変オリフィス３４を設ける。In order to control the working oil pressure in the oil chamber 21 based on the torsion of the torsion bar 26, the annular passage 2
A variable orifice 34 is provided within 7.

可変オリフィス３４は、前輪用出力軸６に対して相対回
転可能にトーク」ンバー２６に結合した環状Ａリフイス
ブツシュ３５と、トーションバー２６に対して相対回転
可能に前輪用出力軸６に結合した環状オリフィスブツシ
ュ３６とを互いに摺接させて構成し、ブツシュ３５．３
６の内周部分には、軸方向スリット３５ａ　、　３６ａ
を、トーシミンバ−２６が捩じれていない状態で、第３
図（ａ　）に示すように互いに円周方向へずれる位置に
て、それぞれ形成する。The variable orifice 34 includes an annular A-refrigerated bush 35 coupled to the token bar 26 so as to be rotatable relative to the output shaft 6 for the front wheels, and an annular orifice coupled to the output shaft 6 for the front wheels so as to be rotatable relative to the torsion bar 26. The bushings 35.3 are constructed by slidingly contacting each other.
Axial slits 35a and 36a are provided in the inner peripheral portion of 6.
, when the Toshimin bar 26 is not twisted, the third
As shown in Figure (a), they are formed at positions offset from each other in the circumferential direction.

尚ここでは、軸方向スリット３５ａの、軸線と直交する
方向の断面形状を、その半径方向寸法が周方向へ一定と
なるものとし、一方、軸方向スリット３６ａの、軸線と
直交する方向の断面形状を、その半径方向寸法が軸方向
スリン１〜３５ａから周方向へ離間するに従って増加す
るものとする。Here, the cross-sectional shape of the axial slit 35a in the direction orthogonal to the axis is assumed to have a constant radial dimension in the circumferential direction, while the cross-sectional shape of the axial slit 36a in the direction orthogonal to the axis is assumed to be constant in the circumferential direction. Assume that the radial dimension increases as the distance from the axial liners 1 to 35a in the circumferential direction increases.

かかる可変オリフィス３４にあっては、前輪用出力軸６
に対して中間軸５、ひいてはクラッチドラム１５が、第
３図（ｂ）、（ｃ）に矢印で示すように、中間軸５側か
ら見て時計方向へ相対回転すると、ｉ−一ションバー２
６の捩れにＪ：す、ブツシュ３５がブッシコ３６に対し
て相対回動じて、軸方向スリン１〜３５ａ　、　３６ａ
のオーバーラツプが生じ、このオーバーラツプの周方向
幅が、」＝述した相対回転の増加に応じて増加する。In such a variable orifice 34, the front wheel output shaft 6
When the intermediate shaft 5, and therefore the clutch drum 15, relative to each other, rotate clockwise when viewed from the intermediate shaft 5 side, as shown by the arrows in FIGS. 3(b) and 3(c),
6, the bushing 35 rotates relative to the bushing 36, and the axial rings 1 to 35a, 36a
An overlap occurs, and the circumferential width of this overlap increases as the relative rotation increases.

ここで、軸方向スリット３５ａ　、　３６ａのオーバー
ラツプは、それらのスリット３５ａ　、　３６ａおよび
、ブッシコ３５の相対回動角θを直交座標上に置換して
示す第４図中に斜線部分で示すように、オリフィス開口
部３４ａを画威し、このオリフィス間口部３４ａの断面
＃ｉＳは、上述した軸方向スリット３５ａ。Here, the overlap between the axial slits 35a and 36a is as shown by the hatched area in FIG. The cross section #iS of the orifice opening 34a is the above-mentioned axial slit 35a.

３６ａの断面形状に基づき、断面積Ｓの、回動角θに対
する二階微分値が正（ｄ　２　Ｓ／ｄθ２〉Ｏ）となる
特性にて、オーバーラツプ幅の増加に応じて増加する。Based on the cross-sectional shape of 36a, the second-order differential value of the cross-sectional area S with respect to the rotation angle θ is positive (d 2 S/dθ2>O), and increases as the overlap width increases.

従って、この可変オリフィス３４のオリフィス開度は、
第５図に示すように、その増加の割り合いが、後輪用駆
動軸８と前輪用駆動軸１１との間の差動回転の増加、す
なわちここでは、ΔＮの増加に従って増加するものとな
る。Therefore, the orifice opening degree of this variable orifice 34 is
As shown in FIG. 5, the rate of increase increases as the differential rotation between the rear wheel drive shaft 8 and the front wheel drive shaft 11 increases, that is, in this case, as ΔN increases. .

そして、この断面積Ｓの拡大は、油圧［３０から油室２
１内へ供給される作動油量を油室２１がら固定Ａリフイ
ス２２を通って排出される作動油量よりも増加させて、
油室２１内の作動油圧の一ト昇をもたら４゜ 以上の如くに構成した四輪駆動車にあっては、後輪１０
のスリップがそれほど大きくなく、接輪用駆動軸８と前
輪用駆動軸１１との間の差動回転が小さい（ΔＮ≦１１
００ｒｐどなる）場合には、可変オリフィス３４の開度
がそれほど増加せず、従って、油圧クラッチ１４内の作
動油圧も第６図に示すように、低く保たれ、このことに
より、前輪用駆動軸１１への伝達トルク丁も、第７図に
示すように低く保たれる。The expansion of this cross-sectional area S is due to the increase in the oil pressure [30] to the oil chamber 2.
increasing the amount of hydraulic oil supplied into the interior of the oil chamber 21 from the amount of hydraulic oil discharged from the fixed A refit 22,
In a four-wheel drive vehicle configured such that the hydraulic pressure in the oil chamber 21 is increased by 4° or more, the rear wheel 10
The slip is not so large, and the differential rotation between the contact wheel drive shaft 8 and the front wheel drive shaft 11 is small (ΔN≦11
00 rpm), the opening degree of the variable orifice 34 does not increase that much, and therefore the working oil pressure in the hydraulic clutch 14 is kept low as shown in FIG. The torque transmitted to is also kept low as shown in FIG.

この一方、後輪１０のスリップが大きくなって、後輪用
駆動軸８と前輪用駆動軸１１との間の差動回転が比較的
大きくなる（ΔＮ　＞　１００ｒｒｌｌｌｌとなる）場
合には、ΔＮの増加に対して可変オリフィス３４の聞度
が大幅に増加し、従って、油圧クラッチ１４内の作動油
圧が大幅に上昇して、伝達トルクＴも極めて大きなもの
となる。On the other hand, when the slip of the rear wheels 10 increases and the differential rotation between the rear wheel drive shaft 8 and the front wheel drive shaft 11 becomes relatively large (ΔN > 100rrllll), ΔN In response to the increase, the depth of the variable orifice 34 increases significantly, and therefore the working oil pressure within the hydraulic clutch 14 increases significantly, and the transmitted torque T also becomes extremely large.

このことから、この例の四輪駆動車用動力伝達装置によ
れば、−上述の四輪駆動車を通常の路面上にて走行させ
る場合には、後輪１０のスリップがそれほど大きくなら
ないことから、操舵性がほとんど変化しない程度に、前
輪に駆動力を伝達して走行性能を向上させることができ
、この一方、上述の四輪駆動車を、荒地や泥淳地等の摩
擦係数の低い場所で走行させ、あるいはスタック状態か
ら脱出させる場合には、後輪１０のスリップが大きくな
ることから、前輪に極めて大きな駆動力を伝達して、車
両を充分な駆動力で駆動し、これによって、差動回転が
大きい状態を短時間で解消し得て、粘性カップリング３
３内の粘性油および油圧クラッチ１４のクラッチプレー
ト１７．１８の発熱を有効に防止し、ひいては、動力伝
達装置の、伝達トルクの低下防止と耐久性の大幅な向上
をもたらすことができる。From this, according to the power transmission device for a four-wheel drive vehicle of this example, - When the above-mentioned four-wheel drive vehicle is run on a normal road surface, the slip of the rear wheels 10 does not become so large. , it is possible to improve driving performance by transmitting driving force to the front wheels with almost no change in steering performance.On the other hand, the above-mentioned four-wheel drive vehicle can be used in places with a low coefficient of friction such as rough ground or muddy ground. When the vehicle is driven at a high speed or when the vehicle is to escape from a stuck state, the slip of the rear wheels 10 increases, so an extremely large amount of driving force is transmitted to the front wheels to drive the vehicle with sufficient driving force. The viscous coupling 3 can eliminate the situation of large dynamic rotation in a short time.
This effectively prevents heat generation in the viscous oil in the hydraulic clutch 14 and the clutch plates 17, 18 of the hydraulic clutch 14, thereby preventing the transmission torque from decreasing and significantly improving the durability of the power transmission device.

以上、四輪駆動車用の動力伝達装置の例を示したが、本
案の適用はこれに限定されるものではなく、二輪駆動車
用の動力伝達装置としても適用可能である。特に口承は
しないが、具体的には差動装置を介して連結する左右の
駆動軸間に本装置を１胃すれば良い。本質的な作用は先
に述べた実施例と同様であり、通常の旋回時には左右輪
の差動を許容すると共に、片輪がスタックした場合には
クラッチ１４が締結し、スタック脱出性を向上させる。Although an example of a power transmission device for a four-wheel drive vehicle has been shown above, the application of the present invention is not limited thereto, and can also be applied to a power transmission device for a two-wheel drive vehicle. Although it has not been passed down orally, specifically, this device may be installed between the left and right drive shafts connected via a differential device. The essential operation is the same as that of the previously described embodiment, allowing differential movement between the left and right wheels during normal turning, and in the event that one wheel gets stuck, the clutch 14 is engaged to improve the ability to escape the stuck. .

〈発明の効果） かくしてこの発明の装置によれば、車両を、荒地や泥淳
地その他の摩擦係数の低い場所で走行させる場合、ある
いは、スタック状態から脱出させる場合に、前輪用駆動
軸と後輪用駆動軸との間の差動回転または左右駆動軸間
の差動回転が大きい状態を短時間で解消し得て、動力伝
達装置の、伝達トルクの低下防止と、耐久性の向上とを
もたらすことができる。<Effects of the Invention> Thus, according to the device of the present invention, when the vehicle is driven on rough ground, muddy ground, or other places with a low coefficient of friction, or when the vehicle is released from a stuck state, the front wheel drive shaft and the rear A state where the differential rotation between the wheel drive shafts or the left and right drive shafts is large can be resolved in a short time, and the transmission torque of the power transmission device is prevented from decreasing and the durability is improved. can bring.

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

第１図はこの発明の車両用動力伝達装置の一実施例を示
す断面図、 第２図はこの例の装置を適用した四輪駆動車の動力伝達
経路を示す路線図、 第３図はこの例における可変オリフィスの作動状態を第
１図の■−■線に沿う断面で示す断面図、第４図はこの
例における可変オリフィスの軸方向スリットを直交座標
系に置換して示す模式図、第５図はこの例における駆動
軸間差動回転−可変オリフィス開度の関係線図、 第６図はこの例における駆動軸間差動回転−クラッチ作
動油圧の関係線図、 第７図はこの例における駆動軸間差動回転−伝達トルク
の関係線図、 第８図は従来の動力伝達装置の駆動軸間差動回転−伝達
トルクの関係線図である。 ５・・・中間軸　　　　　６・・・前輪用出力軸７・・
・動力伝達装置　　８・・・後輪用駆動軸１１・・・前
輪用駆動軸　　１４・・・油圧クラッチ２２・・・粘性
カップリング ３０・・・油圧源　　　　　３４・・・可変オリフィス
第５図 第７図 囲周１改、喀ｔ〔タヒΔＮ（ＲＰｆｉクツ回転数：！ｚ
ｉｕｔＲＰｓ）Fig. 1 is a sectional view showing one embodiment of the vehicle power transmission device of the present invention, Fig. 2 is a route diagram showing the power transmission path of a four-wheel drive vehicle to which the device of this example is applied, and Fig. 3 is this FIG. 4 is a schematic diagram showing the operating state of the variable orifice in this example along the line ■-■ in FIG. Figure 5 is a relationship diagram between the differential rotation between drive shafts and variable orifice opening degree in this example, Figure 6 is a relationship diagram between differential rotation between drive shafts and clutch operating oil pressure in this example, and Figure 7 is a relationship diagram in this example. FIG. 8 is a diagram showing the relationship between the differential rotation between the drive shafts and the transmitted torque in a conventional power transmission device. 5... Intermediate shaft 6... Output shaft for front wheels 7...
- Power transmission device 8... Drive shaft for rear wheels 11... Drive shaft for front wheels 14... Hydraulic clutch 22... Viscous coupling 30... Hydraulic source 34... Variable orifice Fig. 5 7 Figure circumference 1 modification,
iutRPs)

Claims (1)

【特許請求の範囲】 １、第１駆動軸と第２駆動軸とを適宜に駆動結合する油
圧クラッチと、前記第１駆動軸と前記第２駆動軸との間
の差動回転に応じたトルクを発生する粘性カップリング
と、前記トルクに応じて開度変化する可変オリフィスと
、前記可変オリフィスを経て前記油圧クラッチに作動油
圧を供給する油圧源とを具え、前記第１駆動軸および前
記第２駆動軸の間で、前記差動回転に応じた動力伝達を
行う動力伝達装置において、 前記可変オリフィスの形状を、前記差動回転の増加に対
応する前記可変オリフィスの開度の増加の割り合いが前
記差動回転の増加に応じて増加する形状とすることを特
徴とする車両用動力伝達装置。[Claims] 1. A hydraulic clutch that appropriately drives and connects a first drive shaft and a second drive shaft, and a torque that corresponds to differential rotation between the first drive shaft and the second drive shaft. a viscous coupling that generates a viscosity coupling, a variable orifice whose opening degree changes according to the torque, and a hydraulic pressure source that supplies working pressure to the hydraulic clutch via the variable orifice, the first drive shaft and the second drive shaft. In a power transmission device that transmits power between drive shafts according to the differential rotation, the shape of the variable orifice is set such that the rate of increase in the opening degree of the variable orifice corresponding to the increase in the differential rotation is A power transmission device for a vehicle, characterized in that the power transmission device has a shape that increases as the differential rotation increases.