Patent Description:
A drive module used for a hybrid vehicle has a structure configured to transmit a force of a motor and a force of an engine to a transmission. A hybrid drive module includes an input member configured to receive the force of the engine, a motor, an engine clutch configured to connect the input member and the motor, an output member configured to receive the force of the motor and/or the engine and transmit the force to the transmission, and a power transmission part configured to connect the motor and the output member. The power transmission part may be structured to directly connect the motor and the output member or structured to include a torque converter and a lock-up clutch.

The motor may include a stator and a rotor, and the rotor may be installed on a rotor hub. A space in which the clutch and the like are installed is provided in a radial internal space of the rotor defined by the rotor hub. After the clutch and the like are installed in the space, a cover or a hub ridge is installed to cover the space. The hub ridge is installed to rotate integrally with the rotor hub.

The stator is installed in a housing. Further, the input member, the rotor hub, the output member, and the like, which may rotate relative to one another, are installed to be rotatable relative to the housing.

The torque converter and the lock-up clutch, which are included in the power transmission part and connected in parallel between the motor and the output member, are accommodated in a space filled with a fluid for operating the torque converter. Further, a piston plate, which serves to press or release the lock-up clutch, is also accommodated in the space.

Typically, fluid pressure in the space is greatly increased by an operational principle of the torque converter. Therefore, pressure in an operation chamber of the piston plate installed to press the piston plate toward the lock-up clutch needs to be higher than pressure of the fluid in the space. For example, in case that the pressure in the space is about <NUM> bar, the pressure of the operation chamber needs to be about <NUM> bar so that torque applied to the lock-up clutch may be about <NUM> bar.

That is, pressure around the piston plate, which is disposed in the space in which the piston plate for pressing the lock-up clutch is installed, may be referred to as pressure in the compensation chamber of the piston plate. In case that the pressure in the compensation chamber is formed by the fluid for operating the torque converter, the pressure, which needs to be applied to the operation chamber to that extent, needs to be high. For this reason, there is a problem in that fuel economy inevitably deteriorates.

<CIT> provides a torque converter and electric motor configuration in a hybrid module. <CIT> provides an assembly for driveably connecting an internal combustion (IC) engine and an electric machine to a transmission input.

The present invention has been made in an effort to solve the above-mentioned problem, and an object of the present invention is to provide a hybrid drive module, which is capable of ensuring sufficient pressure to be applied to a lock-up clutch even though pressure in an operation chamber in which a piston plate presses a lock-up clutch is set to be low under a condition of fluid pressure in a space in which a torque converter (fluid clutch) is embedded.

Another object of the present invention is to provide a hybrid drive module that may be simply assembled and minimize an increase in number of components.

According to the present invention, a hybrid drive module disposed between an engine and a transmission of a power system and having a motor configured to provide power to the transmission is provided as defined by independent claim <NUM>.

The hybrid drive module includes a housing in which the stator is fixed, and a rotor hub disposed in the housing so that the rotor of the motor is installed on the rotor hub.

A power transmission part is connected to the rotor hub.

The power transmission part includes a fluid clutch connected to the rotor hub, and a first clutch pack connected to the rotor hub.

The fluid clutch may be a torque converter. That is, the fluid clutch may include an impeller and a turbine facing each other and having a half torus shape, and a reactor disposed between the impeller and the turbine and connected to a fixed end through a one-way clutch.

The rotor hub has a first accommodation space configured to accommodate the fluid clutch and the first clutch pack. The first accommodation space is filled with a fluid for operating the fluid clutch and cooling the first clutch pack.

A first piston plate configured to press or release the first clutch pack is installed in the first accommodation space.

The first piston plate has a shape extending in the radial direction and has a first surface directed toward any one side in the axial direction, and a second surface directed toward a side opposite to one side. That is, the first surface and the second surface are opposite to (face away from) each other.

Therefore, the first surface faces the first compensation chamber filled with the fluid with the pressure lower than the pressure of the fluid in the first accommodation space. As the first compensation chamber is provided as described above, it is possible to further reduce operating pressure for operating the first piston plate in comparison with a case in which the first compensation chamber is not present.

The second surface faces the first operation chamber filled with the fluid with the pressure for moving the first piston plate to the first clutch pack. The presence of the first compensation chamber reduces the pressure of the fluid stored in the first operation chamber.

The first compensation chamber is disposed between the rotor hub and the first piston plate in the axial direction.

The first compensation chamber is defined by the first surface and a first guide cylinder disposed to face the first surface in the axial direction.

The first guide cylinder is connected to the rotor hub.

In this case, a radial inner end of the first guide cylinder is connected to the rotor hub at a side positioned radially inward of the first clutch pack.

A first return spring may be installed in the first compensation chamber. The first return spring provides elasticity in the axial direction. One side of the first return spring may be supported by the first guide cylinder, and the other side of the first return spring may be supported by the first piston plate. That is, the first return spring may elastically press the first piston plate in a direction in which the first piston plate moves away from the first guide cylinder in the axial direction.

The first piston plate is disposed between the rotor hub and the first operation chamber in the axial direction.

The first operation chamber is defined by the second surface and a support cylinder disposed to face the second surface in the axial direction.

The support cylinder may be connected to the rotor hub.

In this case, a radial inner end of the support cylinder may be connected to the rotor hub at a side positioned radially inward of the first clutch pack.

The rotor hub has a rotor holder extending in the axial direction so that the rotor is fixed to the rotor holder, and a hub plate extending from the rotor holder to the radial inner side.

The hub plate extends in the radial direction while traversing an internal space of the hybrid drive module and divide the internal space of the hybrid drive module into the first accommodation space and the second accommodation space in the axial direction.

The first piston plate may be disposed so that the first surface faces the hub plate.

A second clutch pack is accommodated in the second accommodation space. The fluid for cooling the second clutch pack fills the second accommodation space and flow.

The fluid in the second accommodation space fills the first compensation chamber through the rotor hub. With the above-mentioned configuration, the first compensation chamber is filled with the fluid with pressure lower than pressure in the first accommodation space only by simply supplying the fluid in the second accommodation space to the first compensation chamber through the first compensation hole provided in the rotor hub without adding a separate flow path or component.

A second piston plate configured to press or release the second clutch pack may be installed in the second accommodation space.

The second piston plate may have a third surface facing the second clutch pack in the axial direction, and a fourth surface opposite to the third surface in the axial direction.

The third surface may face a second compensation chamber filled with the fluid in the second accommodation space.

The fourth surface may face a second operation chamber filled with the fluid that generates pressure for moving the second piston plate toward the second clutch pack.

A hub ridge is connected to a front side of the rotor holder, and the second piston plate may be slidably installed on the hub ridge in the axial direction.

The hub ridge and the fourth surface may define the second operation chamber.

A second guide cylinder may be connected to the hub ridge, and the second piston plate may be disposed between the hub ridge and the second guide cylinder in the axial direction.

The third surface and the second guide cylinder may define the second compensation chamber.

A second return spring may be installed in the second compensation chamber. The second return spring provides elasticity in the axial direction. One side of the second return spring may be supported by the second guide cylinder, and the other side of the second return spring may be supported by the second piston plate. That is, the second return spring may elastically press the second piston plate in a direction in which the second piston plate moves away from the second guide cylinder in the axial direction.

The hybrid drive module may have an output member configured to transmit an output of the motor or the engine to the transmission.

The rotor hub may be connected to the first clutch pack at a radial inner side of the first clutch pack. The output member may be connected to the first clutch pack at a radial outer side of the first clutch pack. Therefore, it is possible to further simplify the structure and method of assembling the first compensation chamber, the first operation chamber, and the first piston plate.

The impeller may be connected to the rotor hub, and the turbine may be connected to the output member.

The output member may be connected to the first clutch pack through the turbine.

The first clutch pack may constitute the lock-up clutch configured to directly couple or decouple the rotor hub and the output member.

The second clutch pack may constitute the engine clutch configured to connect or disconnect the engine and the rotor hub.

According to the hybrid drive module of the present invention, it is possible to reduce the pressure in the operation chamber of the piston plate for pressing the lock-up clutch installed in a fluid condition such as the torque converter (fluid clutch), thereby reducing an unnecessary loss of power and improving fuel economy.

According to the present invention, the compensation chamber of the piston plate for pressing the lock-up clutch installed in a fluid condition such as the torque converter (fluid clutch) may be separately provided, thereby reducing the pressure of the operation chamber, minimizing an increase in number of components, and simplifying an assembling process.

The specific effects of the present invention, together with the above-mentioned effects, will be described along with the description of specific items for carrying out the present invention.

The terms including ordinal numbers such as "first," "second," and the like may be used to describe various constituent elements, but the constituent elements are not limited by the terms. These terms are used only to distinguish one constituent element from another constituent element.

When one constituent element is described as being "coupled" or "connected" to another constituent element, it should be understood that one constituent element can be coupled or connected directly to another constituent element, and an intervening constituent element can also be present between the constituent elements. When one constituent element is described as being "coupled directly to" or "connected directly to" another constituent element, it should be understood that no intervening constituent element is present between the constituent elements.

When one constituent element is described as being "disposed above" or "disposed below" another constituent element, it should be understood that one constituent element can be disposed directly on another constituent element, and an intervening constituent element can also be present between the constituent elements.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application.

Because a hybrid drive module according to an embodiment is symmetrical with respect to an axis, only the half of the hybrid drive module based on the axis is illustrated for the convenience of illustration. In addition, for the convenience of description, a direction along a longitudinal direction of an axis defining a center of a rotation of the hybrid drive module is defined as an axial direction. That is, a forward/backward direction or an axial direction is defined as a direction parallel to a rotation axis. A front (forward) means any one direction of a power source, e.g., a direction toward an engine. A rear (backward) means the other direction, e.g., a direction toward a transmission. Therefore, a front surface means a surface facing forward, and a rear surface means a surface facing backward.

A radial direction means a direction toward or away from a center of the rotation axis along a straight line passing through the center of the rotation axis on the plane perpendicular to the rotation axis. A direction radially away from the center is referred to as a centrifugal direction, and a direction toward the center is referred to as a centripetal direction.

A peripheral direction or a circumferential direction means a direction surrounding a periphery of the rotation axis. An outer periphery means an outer circumference, and an inner periphery means an inner circumference. Therefore, an outer peripheral surface is a surface facing away from the rotation axis, and an inner peripheral surface is a surface facing the rotation axis.

A circumferential surface means a surface, a normal line of which is directed in a circumferential direction.

A hybrid drive module of the present invention is disposed between an engine and a transmission of a power system.

The hybrid drive module includes a motor <NUM> configured to provide power to a transmission. The motor <NUM> may include a stator <NUM> and a rotor <NUM>.

The stator <NUM> is fixed to a housing <NUM> of the hybrid drive module. Further, the rotor <NUM> is accommodated in the housing <NUM> at a side positioned radially inward of the stator <NUM>. The rotor <NUM> may be fixed to a rotor hub <NUM> disposed in the housing <NUM>.

An input member <NUM> is provided at a front center of the housing <NUM> and connected to an engine to receive power of the engine. The input member <NUM> is supported to be rotatable relative to the housing <NUM> by means of a first bearing B1.

The input member <NUM> further protrudes forward than the housing <NUM>, and a spline <NUM> is formed on an outer peripheral surface of the protruding portion. A torsional damper <NUM> is connected to the spline <NUM>. An input side of the torsional damper <NUM> is connected to the engine, and an output side of the torsional damper <NUM> is connected to the input member <NUM>.

A sealing member S1 is disposed forward of the first bearing B1 and interposed between an inner peripheral surface of the housing <NUM> and an outer peripheral surface of the input member <NUM>. That is, a space, which is filled with a fluid supplied from the transmission, is disposed rearward of the sealing member S1, and the sealing member S1 and the housing <NUM> define a boundary of the space filled with the fluid. That is, the torsional damper <NUM> may be a dry spring damper.

The rotor hub <NUM> may include a rotor holder <NUM> configured to fix the rotor <NUM>, and a hub plate <NUM> extending radially inward from the rotor holder <NUM>. The rotor holder <NUM> has a shape similar to a cylinder extending in an axial direction.

The hub plate <NUM> is connected to an approximately central portion in the axial direction of the rotor holder <NUM>.

A central axis extension portion <NUM>, which extends in the axial direction, is provided at a radial inner end of the hub plate <NUM>. The central axis extension portion <NUM> is disposed rearward of the input member <NUM> in the axial direction. A partial section in the axial direction of the central axis extension portion <NUM> overlaps the input member <NUM>. A third bearing B3 is interposed in a section in which the input member <NUM> and the central axis extension portion <NUM> overlap each other. The third bearing B3 supports the input member <NUM> and the central axis extension portion <NUM> so that the input member <NUM> and the central axis extension portion <NUM> rotate relative to each other.

A hub ridge <NUM> is connected to a front end of the rotor holder <NUM>. The hub ridge <NUM> is fitted with the rotor holder <NUM> in a way that the hub ridge <NUM> is accommodated in the radial internal space of the rotor holder <NUM> from a location disposed forward of the rotor holder <NUM>. In this case, a hub coupling portion <NUM> provided at a radial outer end of the hub ridge <NUM> may engage with the rotor holder <NUM> to restrict a rotation. In addition, a snap ring is fitted with the rotor holder <NUM> to prevent the hub ridge <NUM> from separating from the rotor holder <NUM>.

A piston installation portion <NUM>, which extends rearward, is provided at the radial inner end of the hub ridge <NUM>, and a radial inner end of the housing <NUM> also extends rearward at a side positioned radially inward of the hub ridge <NUM>. A second bearing B2 is interposed between these components. That is, the hub ridge <NUM> is rotatably supported on the housing <NUM>.

The rotor hub <NUM> is rotatably supported on the housing <NUM> by means of the second bearing B2 and rotatably supported on the housing <NUM> by means of the third bearing B3, the input member <NUM>, and the first bearing B1.

A back cover <NUM> is connected to a rear end of the rotor holder <NUM>. The back cover <NUM> is integrally fixed to a rear end of the rotor holder <NUM> by means of a fastening means such as a bolt.

A radial internal space of the rotor holder <NUM> of the rotor hub <NUM> defines a space filled with a fluid such as transmission oil. The space may be divided into a first accommodation space R1 and a second accommodation space R2 by the hub plate <NUM>. The first accommodation space R1 may be defined as a space between the hub plate <NUM> and the back cover <NUM> in the axial direction. The second accommodation space R2 may be defined as space between the hub ridge <NUM> and the hub plate <NUM> in the axial direction. That is, the second accommodation space R2 is disposed forward of the first accommodation space R1.

The input member <NUM> is disposed at a side of the second accommodation space R2. The input member <NUM> and the rotor hub <NUM> are connected through an engine clutch <NUM>. The engine clutch <NUM> is also disposed in the second accommodation space R2. The engine clutch <NUM> has a second clutch pack <NUM> in which a plurality of friction plates is disposed in the axial direction.

A radial outer side of the second clutch pack <NUM> is fixed to an inner peripheral surface of the rotor holder <NUM> of the rotor hub <NUM>, and a radial inner side of the second clutch pack <NUM> is fixed to an input plate <NUM> extending from a rear end to a radial outer side of the input member <NUM>.

A second piston plate <NUM> is disposed forward of the second clutch pack <NUM>. The second piston plate <NUM> is disposed between the hub ridge <NUM> and the second clutch pack <NUM> in the axial direction. An outer peripheral surface of the second piston plate <NUM> slidably adjoins the hub ridge <NUM>, and an inner peripheral surface of the second piston plate <NUM> also slidably adjoins the hub ridge <NUM>. A space between the second piston plate <NUM> and the hub ridge <NUM> defines a second operation chamber <NUM>.

The hub ridge <NUM> has a second operation hole <NUM> connected to communicate with the second operation chamber <NUM>.

A second guide cylinder <NUM> is disposed forward of the second clutch pack <NUM> and rearward of the second piston plate <NUM>. An outer peripheral surface of the second guide cylinder <NUM> adjoins the second piston plate <NUM>. A radial inner end of the second guide cylinder <NUM> is fixed to the hub ridge <NUM>. Therefore, the second piston plate <NUM> slidably adjoins the second guide cylinder <NUM>. A space between the second piston plate <NUM> and the second guide cylinder <NUM> defines a second compensation chamber <NUM>. A second return spring <NUM> is accommodated in the second compensation chamber <NUM>. The second return spring <NUM> is interposed between the second piston plate <NUM> and the second guide cylinder <NUM> and elastically presses the second piston plate <NUM> in a direction in which the second piston plate <NUM> moves away from the second guide cylinder <NUM>. That is, the second return spring <NUM> is elastically biased in a direction in which the second piston plate <NUM> releases the second clutch pack <NUM>.

The hub ridge <NUM> has a second compensation hole <NUM> connected to communicate with the second compensation chamber <NUM>.

The housing <NUM> has a first flow path A1 that communicates with the second operation hole <NUM>. That is, as illustrated in <FIG>, the fluid to be supplied to the second operation chamber <NUM> is supplied to the second operation chamber <NUM> through the first flow path A1 and the second operation hole <NUM>.

The housing <NUM> has a second flow path A2 that communicates with the second accommodation space R2. Further, the second compensation hole <NUM> communicates with the second accommodation space R2. Therefore, as illustrated in <FIG>, the fluid to be supplied to the second compensation chamber <NUM> is supplied to the second compensation chamber <NUM> through the second flow path A2, the second accommodation space R2, and the second compensation hole <NUM>.

In the housing <NUM>, the first flow path A1 and the second flow path A2 do not communicate with each other.

In the second accommodation space R2, the first bearing B1, the second bearing B2, and the third bearing B3 are disposed, and the second clutch pack <NUM> is also disposed. A first flow path hole <NUM> and a second flow path hole <NUM> may be respectively formed in the input member <NUM> and the input plate <NUM> so that the fluid, which is stored in the second accommodation space R2, smoothly flows through the second flow path A2. Therefore, as illustrated in <FIG>, the fluid supplied through the second flow path A2 fills the second accommodation space R2 and lubricates and cools the bearings B1, B2, and B3 and the second clutch pack <NUM>. That is, it can be seen that the second clutch pack <NUM> is a wet clutch.

When the pressure of the fluid supplied through the first flow path A1 overcomes the pressure of the fluid supplied through the second flow path A2 and the elastic force of the second return spring <NUM>, the second piston plate <NUM> presses the second clutch pack <NUM>. Otherwise, the second piston plate <NUM> releases the second clutch pack <NUM>.

A power transmission part may be accommodated in a first accommodation space of the rotor hub <NUM>.

The power transmission part may include a fluid clutch <NUM> connected to the rotor hub <NUM>, and a first clutch pack <NUM> connected to the rotor hub <NUM>.

The fluid clutch <NUM> may be a torque converter. That is, the fluid clutch may include an impeller <NUM> and a turbine <NUM> facing each other and having a half torus shape, and a reactor <NUM> disposed between the impeller <NUM> and the turbine <NUM> and connected to a fixed end <NUM> through a one-way clutch <NUM>.

The impeller <NUM> may be provided on the back cover <NUM>. Therefore, the rotation of the impeller <NUM> relative to the rotor hub <NUM> is restricted.

A pump drive hub <NUM> is provided at a radial inner side of the back cover <NUM> and extends rearward. When the rotor hub <NUM> rotates, a rotational force of the rotor hub <NUM> operates the pump by means of the back cover <NUM> and the pump drive hub <NUM>. Therefore, the transmission oil is supplied to the first accommodation space R1. Therefore, the first accommodation space R1 is filled with the fluid for operating the fluid clutch <NUM> and cooling the first clutch pack <NUM>.

The turbine <NUM> is disposed forward of the impeller <NUM> while facing the impeller <NUM>. A radial inner side of a turbine plate <NUM>, on which the turbine <NUM> is installed, is connected to an output member <NUM>. The output member <NUM> is connected to an input side of the transmission.

The reactor <NUM> is disposed between the impeller <NUM> and the turbine <NUM>. The reactor <NUM> is installed at the fixed end <NUM> by means of the one-way clutch <NUM>. The reactor <NUM> rotates relative to the back cover <NUM> and rotates relative to the output member <NUM>. A fourth bearing B4 is interposed between the reactor <NUM> and the back cover <NUM> and a fifth bearing B5 is interposed between the reactor <NUM> and the output member <NUM> in order to allow and support the relative rotation between the back cover <NUM> and the reactor <NUM> and the relative rotation between the output member <NUM> and the reactor <NUM>. That is, the output member <NUM> and the back cover <NUM> are rotatably supported on the fixed end <NUM>.

In the second accommodation space R2, a lock-up clutch <NUM> is disposed forward of the turbine plate <NUM>. The lock-up clutch <NUM> has a first clutch pack <NUM> in which a plurality of friction plates is disposed in the axial direction.

The first clutch pack <NUM> is disposed between the rotor hub <NUM> and the output member <NUM> and connects or disconnects the rotor hub <NUM> and the output member <NUM>.

A radial inner side of the first clutch pack <NUM> is connected to the rotor hub <NUM>. Specifically, a lock-up input member <NUM> is provided at a radial inner side of the first clutch pack <NUM>, and the lock-up input member <NUM> is connected to the hub plate <NUM> of the rotor hub <NUM>.

A radial outer side of the first clutch pack <NUM> is connected to the output member <NUM>. Specifically, a lock-up output member <NUM> having a drum shape is provided at the radial outer side of the first clutch pack <NUM>, and the lock-up input member <NUM> is fixed to the turbine plate <NUM> connected to the output member <NUM>.

That is, an input side of the first clutch pack <NUM> is disposed at a radial inner side thereof, and an output side of the first clutch pack <NUM> is disposed at a radial outer side thereof.

A first piston plate <NUM> configured to press or release the first clutch pack <NUM> is installed in the first accommodation space R1.

The first piston plate <NUM> has a shape extending in the radial direction and has a first surface directed toward any one side in the axial direction, and a second surface directed toward a side opposite to one side. That is, the first surface and the second surface are opposite to (face away from) each other.

The first surface is disposed to face the hub plate <NUM> and disposed to face the first clutch pack <NUM>. Further, the second surface is disposed to be directed toward the torque converter.

A radial inner end of the first piston plate <NUM> faces and adjoins, in the radial direction, an outer peripheral surface of an axial extension portion <NUM> that is a portion in which the hub plate <NUM> extends rearward in the axial direction between the rotor holder <NUM> and the central axis extension portion <NUM>. A radial inner end of the first piston plate <NUM> slidably adjoins a portion thereof that faces the hub plate <NUM>.

A first guide cylinder <NUM> is disposed forward of the first piston plate <NUM>. The first guide cylinder <NUM> is disposed between the first piston plate <NUM> and the first clutch pack <NUM>. A radial inner end of the first guide cylinder <NUM> is fixed to the hub plate <NUM> of the rotor hub <NUM>, and a radial outer end of the first guide cylinder <NUM> adjoins the first piston plate <NUM>. The radial inner end of the first guide cylinder <NUM> is connected to the rotor hub <NUM> at a side positioned radially inward of the first clutch pack <NUM>. The first piston plate <NUM> slidably adjoins a radial outer end of the first guide cylinder <NUM>.

The first guide cylinder <NUM> and the first piston plate <NUM> define a first compensation chamber <NUM> for the first piston plate <NUM>. The first surface of the first piston plate <NUM> faces the first compensation chamber <NUM>.

A first return spring <NUM> is installed in the first compensation chamber <NUM>. The first return spring <NUM> is interposed between the first guide cylinder <NUM> and the first piston plate and elastically presses the first piston plate <NUM> in a direction in which the first piston plate <NUM> moves away from the first guide cylinder <NUM>. That is, the first return spring <NUM> elastically biases the first piston plate <NUM> in a direction in which the first piston plate <NUM> presses or releases the first clutch pack <NUM>.

A support cylinder <NUM> is disposed rearward of the first piston plate <NUM>. A radial inner end of the support cylinder <NUM> is fixed to the hub plate <NUM> of the rotor hub <NUM> at a side positioned radially inward of the first clutch pack <NUM>. Further, a radial outer end of the first piston plate <NUM> slidably adjoins the support cylinder <NUM>.

The support cylinder <NUM> and the first piston plate <NUM> define a first operation chamber <NUM> for the first piston plate <NUM>. The second surface of the first piston plate <NUM> faces the first operation chamber <NUM>.

A first compensation hole <NUM> is formed in the hub plate <NUM> and disposed between the portion where the hub plate <NUM> is connected to the first guide cylinder <NUM> and the portion where the hub plate <NUM> adjoins the first piston plate <NUM>. Further, the first compensation hole <NUM> is formed such that the first compensation chamber <NUM> and the second accommodation space R2 communicate with each other. Therefore, as illustrated in <FIG>, the fluid, which fills the second accommodation space R2 through the second flow path A2, may be introduced into the first compensation chamber <NUM>.

A first operation hole <NUM> is formed in the hub plate <NUM> and disposed between the portion where the hub plate <NUM> adjoins the first piston plate <NUM> and the portion where the hub plate <NUM> is connected to the support cylinder <NUM>.

The output member <NUM> has a hollow shaft shape. Further, a spline is formed on an inner peripheral surface of the hollow shaft shape and connected to the input side of the transmission. The hollow portion of the output member <NUM> defines a third flow path A3 through which the fluid is supplied to the first operation chamber <NUM>.

The axial extension portion <NUM> of the hub plate <NUM> adjoins the output member <NUM> so that the axial extension portion <NUM> may rotate relative to the output member <NUM>. An inner peripheral surface of the rear end of the axial extension portion <NUM> adjoins the output member <NUM> with a sealing member interposed therebetween.

The first operation hole <NUM> is formed such that the first operation chamber <NUM> and the hollow portion of the output member <NUM> communicate with each other. Therefore, as illustrated in <FIG>, the transmission oil supplied through the third flow path A3 may be introduced into the first operation chamber <NUM> through the first operation hole <NUM>.

Meanwhile, a space of the first accommodation space R1, in which oil flows to supply the fluid to the torque converter, may be divided into a first space between the hub plate <NUM> and the first guide cylinder <NUM>, a second space between the support cylinder <NUM> and the turbine plate <NUM>, and a third space disposed in the torus.

Further, a first circulation flow path hole <NUM> is formed in the hub plate <NUM> and connected so that the first space and the second space communicate with each other. In addition, a second circulation flow path hole <NUM> is formed in the output member <NUM> and connected so that the second space and the third space communicate with each other.

A space between the fixed end <NUM> and the output member <NUM> may define a fourth flow path A4 for supplying the fluid from the transmission to the torque converter.

As illustrated in <FIG>, when the fluid is supplied through the fourth flow path A4, the fluid may flow to the second space through the second circulation flow path hole <NUM> of the output member <NUM> and flow from the second space in a centrifugal direction. In addition, a part of the fluid, which has flown to the second space through the second circulation flow path hole <NUM>, may flow to the first space through the first circulation flow path hole <NUM> and flow from the first space in the centrifugal direction.

The fluid, which has flown from the first space and the second space in the centrifugal direction, may be introduced into a third space at a radial outer side of the torus. Although not illustrated, a part of the fluid supplied through the fourth flow path may, of course, be introduced directly to the third space through the space between the output member <NUM> and the reactor <NUM>.

The oil introduced into the third space may be discharged to the transmission through the space between the reactor <NUM> and the back cover <NUM>.

During the circulation process of the fluid, the first clutch pack <NUM>, the one-way clutch <NUM>, the fourth bearing B4, and the fifth bearing B5 may be lubricated and cooled.

The pressure of the fluid stored in the first accommodation space R1 is maintained as high pressure because of the characteristics of the torque converter. In contrast, the pressure of the fluid stored in the first compensation chamber <NUM> just corresponds to the pressure of the fluid stored in the second accommodation space R2. The fluid stored in the second accommodation space R2 has the pressure that generates a flow of fluid that cools or lubricates the bearings B1, B2, and B3 and the second clutch pack <NUM>.

Therefore, the first surface of the first piston plate <NUM> faces the first compensation chamber <NUM> filled with the fluid with the pressure lower than the pressure of the fluid in the first accommodation space R1. Further, the second surface faces the first operation chamber <NUM> filled with the fluid with the pressure for moving the first piston plate <NUM> to the first clutch pack <NUM>.

Therefore, according to the present invention, it is possible to further reduce operating pressure for operating the first piston plate <NUM> in comparison with a structure in which the first compensation chamber <NUM> is not present. That is, the presence of the first compensation chamber <NUM> may further increase the pressure of the first piston plate <NUM> applied to the first clutch pack <NUM> even in a case in which the pressure of the fluid stored in the first operation chamber <NUM> is further lowered.

In addition, according to the present invention, it is not necessary to configure a separate oil flow path or add a separate component to configure the first compensation chamber <NUM> and fill the first compensation chamber <NUM> with oil. Further, it is possible to fill the first compensation chamber <NUM> with the oil in the second accommodation space R2 only by simply forming the first compensation hole <NUM> in the hub plate <NUM> that defines the boundary with the first compensation chamber <NUM>.

Claim 1:
A hybrid drive module, which is disposed between an engine and a transmission of a power system and includes a motor (<NUM>) configured to provide power to the transmission, the hybrid drive module comprising:
a rotor hub <NUM> having a rotor holder (<NUM>) to which a rotor (<NUM>) of the motor (<NUM>) is fixed and a hub plate <NUM> extending from the rotor holder (<NUM>) to a radial inner side;
a fluid clutch (<NUM>) connected to the rotor hub (<NUM>);
a first clutch pack (<NUM>) connected to the rotor hub (<NUM>);
a first piston plate (<NUM>) configured to press or release the first clutch pack (<NUM>);
a first accommodation space (R1) and a second accommodation space (R2) in the axial direction into which internal space of the hybrid drive module is divided by the hub plate (<NUM>), wherein the first accommodation space (R1) is provided in the rotor hub (<NUM>), configured to accommodate the fluid clutch (<NUM>), the first clutch pack (<NUM>) and the first piston plate (<NUM>), and configured to allow a fluid for operating the fluid clutch (<NUM>) and cooling the first clutch pack (<NUM>) to flow and fill the first accommodation space (R1); and
a second clutch pack (<NUM>) accommodated in the second accommodation space (R2),
wherein the first piston plate (<NUM>) has a first surface directed toward the first clutch pack (<NUM>) in an axial direction, and a second surface opposite to the first surface in the axial direction,
wherein the second surface faces a first operation chamber (<NUM>) filled with a fluid that generates pressure for moving the first piston plate (<NUM>) toward the first clutch pack (<NUM>), and
wherein a fluid for cooling the second clutch pack (<NUM>) fills the second accommodation space (R2) and flows, characterized in that
the first surface faces a first compensation chamber (<NUM>) filled with a fluid with pressure lower than pressure of the fluid in the first accommodation space (R1), and the hub plate (<NUM>), and
the fluid in the second accommodation space (R2) fills the first compensation chamber (<NUM>) through the rotor hub (<NUM>).