Dual function apparatus for clutch feed and system retention

This Application claims the benefit of U.S. Provisional Application 60/613,557, filed Sep. 27, 2004, which is hereby incorporated by reference in its entirety.

This invention relates to a dual function apparatus for a hybrid electro-mechanical vehicular transmission.

A hybrid electro-mechanical vehicular transmission utilizes interactive planetary gear arrangements that are operatively connected to an engine and two motor/generators. Selective utilization of torque transfer devices such as a clutch enable power transfer via the planetary gear arrangements from the engine and/or motor/generators to the output member of the transmission.

A power transmission in an electro-mechanical transmission is described in commonly owned U. S. Provisional Application entitled Electrically Variable Transmission with Selective Fixed Ratio Operation, Ser. No. 11/071406, Holmes et al., filed Mar. 3, 2005, and hereby incorporated by reference in its entirety.

An improved hybrid transmission including two electric motor/generator modules and a plurality of planetary gear sets operatively connectable to the motor/generators and to an engine is provided. Novel structural and packaging schemes enhance the function and efficiency of the transmission. More precisely, the present invention relates to an improved apparatus for retaining a clutch hub and providing hydraulic fluid to actuate a clutch.

The apparatus of the present invention includes a fluid source in fluid communication with a pump adapted to draw fluid therefrom. A housing member defines a first flow passage in fluid communication with the pump. A center support is disposed within the housing member and defines a second flow passage in fluid communication with the first flow passage. A clutch hub is attached to the center support and a clutch is disposed within the clutch hub. A plurality of fasteners attach the center support to the clutch hub. At least one of the fasteners is a hollow fastener defining a third flow passage in fluid communication with both the second flow passage and the clutch such that the clutch may be actuated by fluid from the fluid source.

In one aspect of the present invention, the apparatus of the present invention includes a valve body disposed between the pump and the first flow passage to selectively allow fluid from the fluid source to be transferred to the clutch.

In another aspect of the present invention, the plurality of fasteners include a plurality of threaded fasteners adapted to attach the center support and the clutch hub.

In yet another aspect of the present invention, the plurality of fasteners include five fasteners evenly distributed in a circular pattern.

The above features and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

FIG. 1 is a schematic cross-sectional illustration in fragmentary view of a hybrid electrical/mechanical transmission; and

FIG. 2 is a schematic cross-sectional illustration in fragmentary view of a portion of the hybrid electrical/mechanical transmission of FIG. 1 .

Referring to the drawings wherein like reference numbers refer to like components, FIG. 1 shows a vehicle 10 having an electro-mechanical transmission 11 . An input shaft 12 is disposed about a center axis 14 and is operable for transferring power from an engine (not shown) to the transmission 11 . A main shaft 16 is longitudinally disposed and rotatable about the center axis 14 and is engageable with the input shaft 12 . The engagement of one or more of a plurality of clutches such as clutch 15 interconnects one or more of a plurality of planetary gear sets such as planetary gear set 17 to transfer power at varying ratios to an output member 18 . Two electric motor/generators 20 A and 20 B are coaxially oriented about the center axis 14 . Each motor/generator 20 A, 20 B is operatively connectable to a member of one of the planetary gear sets to provide a range of continuously variable speed ratios between the input shaft 12 and the output member 18 , as will be readily understood by those skilled in the art. Each of the motor/generators 20 A, 20 B includes a generally ring-shaped stator 22 A, 22 B, respectively, and a generally ring-shaped rotor 24 A, 24 B rotatable with respect to the respective stator 22 A, 22 B. An end cover 26 is mounted with respect to the main shaft 16 to partially encase the motor/generators 20 A, 20 B within and partially define an interior space 28 . The end cover 26 cooperates with a first portion 30 of a housing member (i.e., an upper portion of a transmission case) and a second portion 32 of the housing member (i.e., a lower portion of the transmission case) to further encase the motors/generators 20 A, 20 B within the interior space 28 .

Referring now to FIG. 2 , a valve body 34 is in fluid communication with a fluid source 35 and a pump 37 , and is capable of delivering pressurized fluid. The fluid source 35 and pump 37 may be located anywhere on the vehicle and fluidly connected with the valve body 34 , as will be understood by those skilled in the art.

A center support 36 is rigidly supported with respect to the main shaft 16 about the center axis 14 and preferably supports the stator 22 A. A first flow passage 38 and a second flow passage 40 are formed within the center support 36 and are in fluid communication with the valve body 34 through a third flow passage 42 formed in the first portion 30 of the transmission case.

The clutch 15 is disposed within a housing or clutch hub 44 adapted to rotate about the center axis 14 . The clutch hub 44 is mounted to the center support 36 by a plurality of fasteners 46 . One or more of the fasteners 46 includes a fourth flow passage 48 disposed therein. In a preferred embodiment there are five fasteners 46 evenly distributed in a circular pattern. Four of the fasteners 46 are preferably solid fasteners 46 a and one of the fasteners 46 is a hollow fastener 46 b defining a flow passage 48 which is in fluid communication with the flow passage 40 and the clutch 15 . The four solid fasteners 46 a each preferably include a threaded end portion 47 to maintain engagement between the clutch hub 44 and the center support 36 , whereas the hollow fastener 46 b is preferably press fit into position between the clutch hub 44 and the center support 36 . While the number and configuration of fasteners 46 have been described in the context of a preferred embodiment, it should be appreciated that alternate quantities and configurations of the fasteners 46 may be envisioned, and that the fasteners 46 may include different combinations of fasteners 46 a and/or 46 b.

Having described the structure of the present invention, it should be appreciated by one skilled in the art that the clutch 15 may be actuated by hydraulic fluid from the fluid source 35 in the following manner. Fluid from the fluid source 35 is delivered by the pump 37 through valve body 34 , then through flow passages 42 , 38 , 40 and 48 , and finally to the clutch 15 for the actuation thereof. Accordingly, the fasteners 46 serve a dual purpose. More precisely, the solid fasteners 46 a serve to retain the clutch hub 44 to the center support 36 and the hollow fastener 46 b provides pressurized hydraulic fluid for the actuation of the clutch 15 .

While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.