Patent Description:
Moving engine accessories to the low speed spool requires a speed converting transmission to take a large speed ratio and turn it into a tighter speed ratio band. One method of doing this is the use of a shifting transmission consisting of clutches that selectively engage different gear ratios. These clutches need to be selectively open or closed such that they can transmit or not transmit torque on a command.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved clutch assemblies. The present disclosure provides a solution for this need. <CIT> relates to a wet clutch power output device and tractor. <CIT> relates to a starter device. <CIT> relates to a clutch assembly. <CIT> relates to a vehicle drive device. <CIT> relates to a transmission with a hydraulic control device.

In an example, a hydraulic clutch assembly can include a shaft defining a shaft channel, one or more hydraulic ports defined through the shaft, and one or more lubrication holes defined through the shaft. A porting manifold according to the claimed invention is disclosed in claim <NUM>.

According to a preferred embodiment of the claimed invention, the control pressure path can include a central axial channel defined partially along an axial length of the porting manifold from a control pressure inlet of the porting manifold, and one or more radial channels defined radially from the central axial channel to a respective control pressure outlet of the porting manifold. According to another preferred embodiment of the claimed invention, the shaft can include a control pressure annulus in fluid communication with the one or more control pressure outlets of the one or more radial channels. The one or more hydraulic ports can be in fluid communication with the control pressure annulus.

According to a further preferred embodiment of the claimed invention, the lubrication flow path can include one or more axial lubrication channels defined at least partially along an axial length of the porting manifold from a lubrication flow inlet of the porting manifold, and one or more radial lubrication channels defined radially from a respective axial lubrication channel to a respective lubrication flow outlet of the porting manifold. According to a last preferred embodiment, the shaft can include a lubrication flow annulus in fluid communication with the one or more lubrication flow outlets of the one or more radial channels. One or more lubrication holes of the one or more lubrication holes can be in fluid communication with the lubrication flow annulus.

The porting manifold can include one or more drive tabs configured to limit insertion into the shaft. The porting manifold can include a plurality of seal grooves. The assembly can include a plurality of manifold seals disposed within the seal grooves and configured to fluidly isolate the control pressure from the lubrication flow within the shaft.

According to the claimed invention, the assembly includes a backstop and a piston disposed on the shaft. The backstop can be fixed to the shaft and the piston can be slidably engaged to the shaft to move relative to the shaft and the backstop. According to the claimed invention, the backstop and the piston define a hydraulic cavity therebetween in fluid communication with the one or more hydraulic ports of the shaft. The piston can be configured to move between a retracted position and an engaged position wherein the piston engages a clutch pack. The piston can be slidably sealed to an outer diameter of the backstop.

According to the claimed invention, the assembly includes a balance dam fixed to the piston and disposed around a portion of the backstop to define a lubrication cavity between a back side of the backstop and the balance dam. A spring can be disposed between the back side of the backstop and the balance dam to bias the piston to the retracted position. According to the claimed invention, at least one lubrication hole of the one or more lubrication holes is defined through the shaft and through the backstop to fluidly communicate with the lubrication cavity.

The assembly can include an inner clutch basket rotationally fixed to the shaft to turn with the shaft, an outer clutch basket rotatably mounted on the shaft to rotate relative to the shaft, and a clutch pack disposed between the inner clutch basket and the outer clutch basket. The clutch pack can be configured to be compressed by the piston in the engaged position to engage the inner clutch basket to the outer clutch basket to cause the outer clutch basket to rotate with the inner clutch basket and the shaft.

In accordance with at least one aspect of this claimed invention, a porting manifold is provided in claim <NUM> and can be configured to be at least partially disposed within a shaft channel of a transmission shaft. The porting manifold can include any embodiment of a manifold disclosed herein (e.g., as described above). According to the claimed invention, the manifold includes a control pressure path configured to be in fluid communication with one or more hydraulic ports of the shaft, and a lubrication flow path configured to be fluid communication with one or more lubrication holes of the shaft. The control pressure path and the lubrication path is fluidly isolated in the porting manifold.

So that those skilled in the art to which the claimed invention appertains will readily understand how to make and use the devices of the present invention without undue experimentation, embodiments thereof will be described in detail herein below with reference to certain figures, wherein:.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features of the present invention. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a hydraulic clutch assembly in accordance with the claimed invention is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments of the present invention are shown in <FIG>.

Referring to <FIG> generally, a hydraulic clutch assembly <NUM> can include a shaft <NUM> defining a shaft channel <NUM>, one or more hydraulic ports <NUM> defined through the shaft <NUM>, and one or more lubrication holes <NUM> defined through the shaft <NUM>. Any other suitable holes and/or construction is contemplated herein.

As shown in <FIG>, a porting manifold <NUM> can be disposed at least partially within the shaft channel <NUM>. The porting manifold <NUM> can include a control pressure path <NUM> in fluid communication with the one or more hydraulic ports <NUM> and a lubrication flow path <NUM> in fluid communication with the one or more lubrication holes <NUM>. As shown, the control pressure path <NUM> and the lubrication path <NUM> can be fluidly isolated in the porting manifold <NUM>.

<FIG> shows another embodiment of a porting manifold <NUM> that is similar to manifold <NUM>, except that the lubrication flow path <NUM> does not pas all the way through the manifold <NUM> (e.g., such an embodiment can be fed lubrication oil from the shaft, left of the manifold as shown). Any other suitable paths and/or arrangement thereof are contemplated herein.

Referring additionally to <FIG> and <FIG>, the control pressure path <NUM> can include a central axial channel 111a defined partially along an axial length of the porting manifold <NUM>, <NUM> from a control pressure inlet 111b of the porting manifold <NUM>, <NUM>. The control pressure path <NUM> can include one or more radial channels 111c defined radially from the central axial channel 111a to a respective control pressure outlet 111d of the porting manifold <NUM>, <NUM>. The shaft <NUM> can include a control pressure annulus <NUM> in fluid communication with the one or more control pressure outlets 111d of the one or more radial channels 111c. The one or more hydraulic ports <NUM> can be in fluid communication with the control pressure annulus <NUM>.

The lubrication flow path <NUM>, <NUM> can include one or more axial lubrication channels 113a, 213a defined at least partially along an axial length of the porting manifold <NUM>, <NUM> from a lubrication flow inlet 113b, 213b of the porting manifold <NUM>, <NUM>. The lubrication flow path <NUM>, <NUM> can include one or more radial lubrication channels 113c, 213c defined radially from a respective axial lubrication channel 113a, 213a to a respective lubrication flow outlet 113d, 213d of the porting manifold <NUM>, <NUM>. The shaft <NUM> can include a lubrication flow annulus <NUM> in fluid communication with the one or more lubrication flow outlets 113d, 213d of the one or more radial channels 213c. One or more lubrication holes <NUM> of the one or more lubrication holes can be in fluid communication with the lubrication flow annulus <NUM>.

The porting manifold <NUM>, <NUM> can include one or more drive tabs <NUM> configured to limit insertion into the shaft <NUM>, for example, and/or to connect the manifold <NUM>, <NUM> to the shaft <NUM>. The porting manifold <NUM>, <NUM> can include a plurality of seal grooves <NUM>. Referring additionally to <FIG>, the assembly <NUM> can include a plurality of manifold seals <NUM> disposed within the seal grooves <NUM> and configured to fluidly isolate the control pressure from the lubrication flow within the shaft <NUM>. The assembly <NUM> can include any other suitable seals to isolate lubrication flow and control pressure (e.g., as shown in <FIG>).

The assembly <NUM> , according to the claimed invention, includes a backstop <NUM> and a piston <NUM> disposed on the shaft <NUM>.

The backstop <NUM> can be fixed to the shaft <NUM> and the piston <NUM> can be slidably engaged to the shaft <NUM> to move relative to the shaft <NUM> and the backstop <NUM>. The backstop <NUM> and the piston <NUM> , according to the claimed invention, define a hydraulic cavity <NUM> therebetween in fluid communication with the one or more hydraulic ports <NUM> of the shaft <NUM>.

As shown in <FIG>, the assembly <NUM> can include a housing <NUM> configured to provide separate connections for the control pressure path <NUM> and the lubrication flow path <NUM>. Any other suitable components are contemplated herein (e.g., a stem <NUM> as shown for connecting to the housing <NUM>).

Referring to <FIG>, <FIG>, the piston <NUM> can be configured to move between a retracted position (e.g., as shown in <FIG>) and an engaged position (e.g., as shown in <FIG>) wherein the piston <NUM> engages a clutch pack <NUM>. As shown, the piston <NUM> can be slidably sealed to an outer diameter of the backstop <NUM> (e.g., via sliding seal <NUM>).

The assembly <NUM> can include a balance dam <NUM> fixed to the piston <NUM> and disposed around a portion of the backstop <NUM> to define a lubrication cavity <NUM> between a back side of the backstop <NUM> and the balance dam <NUM>. A spring <NUM> can be disposed between the back side of the backstop <NUM> and the balance dam <NUM> to bias the piston <NUM> to the retracted position. The spring <NUM> can be any suitable biasing member (e.g., a coil spring, a wavy washer spring). The spring <NUM> can push on the backstop <NUM> and the pressure dam <NUM> with any suitable force configured to be overcome by a suitable control pressure in the hydraulic cavity <NUM>.

At least one lubrication hole <NUM> of the one or more lubrication holes <NUM> is defined through the shaft <NUM> and through the backstop <NUM> to fluidly communicate with the lubrication cavity <NUM>. The lubrication flow can be ported to the cavity <NUM> because control pressure can be intermittent and lubrication flow can be constant to prevent movement of the piston <NUM> toward the engaged position. Any other suitable lubrication holes are contemplated herein.

The assembly <NUM> can include an inner clutch basket <NUM> rotationally fixed to the shaft <NUM> to turn with the shaft <NUM>. The assembly <NUM> can include an outer clutch basket <NUM> rotatably mounted on the shaft <NUM> to rotate relative to the shaft <NUM>. The assembly <NUM> can include a clutch pack <NUM> disposed between the inner clutch basket <NUM> and the outer clutch basket <NUM>. The clutch pack <NUM> can be configured to be compressed by the piston <NUM> in the engaged position (e.g., as shown in <FIG>) to engage the inner clutch basket <NUM> to the outer clutch basket <NUM> to cause the outer clutch basket <NUM> to rotate with the inner clutch basket <NUM> and the shaft <NUM>.

The clutch pack <NUM> can include a plurality of separator discs <NUM> slidably connected to the inner clutch basket <NUM> and a plurality of friction discs <NUM> connected to the outer clutch basket <NUM>. The separator discs <NUM> can be pressed by the piston <NUM> to slide and contact the friction discs <NUM> to engage the separator discus <NUM> to the friction discs <NUM>. It is contemplated that the friction discs <NUM> can be connected to the outer clutch basket <NUM> and the separator discs <NUM> can be connected to the inner clutch basket <NUM>. Any other suitable arrangement and/or clutch pack type is contemplated herein.

The control pressure fluid and/or the lubrication fluid can be an oil, for example. Any other suitable fluid (e.g., hydraulic fluid) is contemplated herein.

In accordance with the claimed invention, a porting manifold, e.g., <NUM>, <NUM> can be configured to be at least partially disposed within a shaft channel of a transmission shaft. The porting manifold can include any embodiment of a manifold disclosed herein (e.g., as described above). According to the claimed invention, the manifold includes a control pressure path configured to be in fluid communication with one or more hydraulic ports of the shaft, and a lubrication flow path configured to be fluid communication with one or more lubrication holes of the shaft. The control pressure path and the lubrication path can be fluidly isolated in the porting manifold.

Referring additionally to <FIG>, any suitable embodiment of an assembly, e.g., <NUM> can be utilized in a transmission <NUM>. For example, transmission <NUM> can be attached to a low spool of a turbomachine engine. The transmission <NUM> can include any suitable number of stages (e.g., <NUM> stages as shown).

In certain embodiments, when control pressure is low (e.g., less than the lubrication flow pressure), the clutch can be open and the outer clutch basket and inner clutch basket can rotate at different speeds. In certain embodiments, when control pressure is high (e.g., above lubrication flow pressure), the clutch can be closed and the outer clutch basket and inner clutch basket rotate at the same speed. Torque is then transmitted between the inner and outer clutch baskets.

Embodiments can utilize a clutch/piston arrangement in a low spool transmission on a jet engine accessory drive. Embodiments use hydraulic power to clamp and unclamp a clutch pack which selectively transmits torque between the inner and outer clutch bell. In certain embodiments, a piston return spring and a centrifugal pressure balance disc/dam ensures predictable operation across a wide operating speed band.

Embodiments include a suitable rotating clutch seal arrangement. Because control pressure and lubrication flow must be directed to the appropriate locations for proper operation, seals can be used to isolate the flow paths needed for proper clutch operation and to prevent unwanted leakage. As disclosed above, embodiments of a seal arrangement isolate two paths of flow/pressure. Embodiments allow for the movement of the clutch piston while sealing.

Claim 1:
A porting manifold (<NUM>, <NUM>) configured to be at least partially disposed within a shaft channel of a transmission shaft, comprising
a control pressure path (<NUM>) configured to be in fluid communication with one or more hydraulic ports (<NUM>) of the shaft (<NUM>);
a lubrication flow path (<NUM>) configured to be in fluid communication with one or more lubrication holes (<NUM>) of the shaft (<NUM>),
wherein the control pressure path (<NUM>) and the lubrication flow path (<NUM>) are fluidly isolated in the porting manifold (<NUM>, <NUM>); characterized in that
the one or more hydraulic ports (<NUM>) of the shaft (<NUM>) are in fluid communication with a hydraulic cavity (<NUM>) defined between a backstop (<NUM>) and a piston (<NUM>) disposed on the shaft (<NUM>); and
wherein the lubrication flow path : (<NUM>) is in fluid communication,via at least one lubrication hole (<NUM>) of the one or more lubrication holes (<NUM>) defined through the shaft (<NUM>) and through the backstop (<NUM>), with a lubrication cavity (<NUM>) between a back side of the backstop (<NUM>) and a balance dam (<NUM>) fixed to the piston (<NUM>) and disposed around a portion of the backstop (<NUM>).