SPLINE CONNECTION
A motor vehicle 10 includes a hydromechanical powersplit transmission 11 having a hydraulic pump motor unit drive shaft 44 and a gear 76. The shaft 44 and gear 76 are drivingly connected together with a spline connection 160. The spline connection 160 includes an internal spline connector 161 and an external spline connector 162. Each spline connector 161, 162 includes a spline portion 166, 174 and a generally smooth portion 168, 175 adjacent its spline portion. During assembly, generally smooth portion 168 of the internal spline connector 160 engages and guides spline portion 174 of the external spline connector 162 to longitudinally and circumferentially align the spline portions 174 and 166. After assembly, the spline portions 166, 174 and the generally smooth portions 168 and 175 are radially aligned with and engage one another to form a rigid driving connection.
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The present patent application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61/641,467 filed May 2, 2012, the disclosure of which is incorporated herein by reference in its entirety. The present patent application also cross references related patent applications filed of even date herewith by the assignee of the present patent application and titled “Hydromechanical Transmission and Assemblies,” “Hydromechanical Transmission With Double Sump Gear Unit Housing,” “Method of Assembly for Hydromechanical Transmission,” “Splash Gear Lubrication System,” and “Park Pawl With Actuator.”
TECHNICAL FIELDThis invention relates generally to a hydromechanical transmission, and more specifically to a hydromechanical powersplit transmission for a hydraulic hybrid vehicle, and to components and assemblies and methods that may be used with such transmissions and elsewhere.
BACKGROUND OF THE INVENTIONHydromechanical transmissions, including hydromechanical powersplit transmissions, are used in hydraulic hybrid vehicles. Such vehicles may include a vehicle prime mover such as an internal combustion engine, at least one hydraulic pump motor unit, a gear set such as a planetary gear set, and an output shaft connecting the planetary gear set to a drive shaft of the vehicle. The internal combustion engine and the hydraulic pump motor unit are connected to the gear set, and the gear set splits power from the internal combustion engine and from the hydraulic pump motor unit in a motoring mode to rotate the drive shaft and propel the vehicle. The pump motor unit may also be used in a pumping mode to capture energy under certain conditions such as braking the vehicle, and the captured energy may be stored in an energy storage device such as a hydraulic accumulator to power the hydraulic pump motor unit in the motoring mode.
Various prior art configurations for hydromechanical powersplit vehicle transmissions may be used in off-highway vehicle applications such as agricultural tractors and wheel loaders or in on-highway applications such as delivery trucks. The ability of the powersplit transmission to provide infinitely variable speed allows the engine to run at its optimum efficiency conditions, while transmission of most power through the mechanical power path rather than through the hydraulic power path may result in relatively high transmission efficiency when hydraulic power is limited or not being used. Smooth and seamless control with uninterrupted transfer of torque from the prime mover and/or the hydraulic pump motor unit to the vehicle drive shaft may result in good performance when compared to manual and automatic transmissions having discrete gear ratios, while elimination of a hydrodynamic torque converter may help achieve efficiency when compared to automatic transmissions.
In transmissions of this type, and in hydromechanical components and assemblies and methods for use in such transmissions and elsewhere, technical problems include difficulties with system complexity, efficiency, size, weight, flexibility, lubrication of components, sump oil fill levels and heat build-up, assembly, repair, transmission of forces and torque in relatively large weight vehicles, and parking lock requirements. More specifically, these technical problems include alignment with other components of a vehicle such as the prime mover engine and the differential, ease of assembly, ease of installation in a vehicle and removal from the vehicle, space availability of the vehicle, space requirements of the transmission and within the transmission, weight of the transmission, smooth operation, transmission control, ease of disassembly and repair, and flexibility to change for use in a variety of different vehicles and different applications. Still more specifically, these technical problems include difficulty assembling and attaching and integrating the hydraulic components, including the hydraulic pump motor units and the controls and drive shafts for the hydraulic pump motor units and the hydraulic flow passages and ports for the hydraulic pump motor units, with the planetary gear set, including the drive gears and planetary gear set components, and assembling those components to the prime mover and differential of the vehicle. Further technical problems include lubrication of gear components, including size and complexity and efficiency of lubrication fluid pumps, and assembly and alignment of spline connections. Further technical problems include complexity of, and forces and stresses imposed on, parking lock mechanisms in relatively large weight vehicles.
SUMMARY OF THE INVENTIONThe present invention addresses certain of the aforementioned technical problems and provides a hydromechanical vehicle transmission and assemblies for use in such transmissions, including spline connection assemblies, and elsewhere. The transmission and assemblies according to the present invention may be used in a motor vehicle in place of a conventional manual or automatic transmission, connected directly to a conventional vehicle prime mover engine drive shaft and differential drive shaft, and situated between typical vehicle frame rails, while providing a configuration that is modular, compact, and capable of kinetic brake energy recovery, with good efficiency.
More specifically, the invention provides a spline connection that includes an internal spline connector and an external spline connector. Each of the spline connectors has a spline portion, and at least one of the spline connectors has a substantially smooth centering portion longitudinally substantially adjacent its spline portion. The spline connectors have a first partially assembled configuration in which the spline portion of one of the spline connectors is radially aligned with the smooth centering portion of the other spline connector for longitudinal and rotational sliding contact. The spline connectors have a second partially assembled configuration in which the spline portions of each of the spline connectors are at least partially radially aligned with one another.
According to one embodiment of the invention, the spline connectors have a fully assembled configuration in which the entire longitudinal extend of the spline portion of the one of the spline connectors may be radially aligned with at least a portion of the longitudinal extent of the spline portion of the other spline connector. Each of the spline connectors may have a substantially smooth generally cylindrical centering portion adjacent its spline portion. The centering portions are only partially radially aligned and the spline portions are only partially radially aligned when the spline connection is in its second partially assembled configuration.
According to one embodiment of the invention, the one spline connector may be the internal spline connector. The substantially smooth centering portion of the internal spline connector may guide the spline portion of the external spline connector into circumferential and longitudinal alignment with the spline portion of the internal spline connection as the spline connectors are displaced from a disassembled configuration to the first partially assembled configuration. The internal spline connector may have a longitudinal extent, and the spline portion of the internal spline connector may have a longitudinal extent of at least about 30%, and preferably 50% to 80%, of the longitudinal extent of the internal spline connector. The internal spline connector may be on a bore in a gear, the external spline connector may be on a shaft, and the gear and the shaft may be in a sump in a hydromechanical transmission in a vehicle.
The invention further provides the combinations set out in the accompanying claims. This Summary is not intended to identify key features or essential features of the claimed subject matter, and these and other features of the invention are more fully described and particularly pointed out in the description and claims set out below. The following description and claims and the annexed drawings set forth in detail certain illustrative embodiments of the invention, and these embodiments indicate but a few of the various ways in which the principles of the invention may be used.
Embodiments of this invention will now be described in further detail with reference to the accompanying drawings, in which:
Referring now to the drawings in greater detail,
Headings are provided in the description below to assist the reader. However, descriptions under all headings relate to the descriptions under each individual heading, so that the complete description below is to be used to understand the description under each individual heading.
Overall Structure and OperationThe object 10 can be any object that uses a transmission for transmitting energy or converting energy to rotational movement. In the preferred embodiment described below, the object 10 is a wheeled land vehicle such as an on-highway truck. The vehicle 10 includes a prime mover 13, which in the preferred embodiment is a conventional internal combustion engine such as a gasoline or diesel or natural gas engine, and an engine drive shaft 14. The vehicle 10 further includes drive wheels 15, a differential 16, and a differential drive shaft 17. The vehicle 10 also includes frame rails 18, which are longitudinally extending beams, which may be steel or other suitable structural material, to which the body (not shown), prime mover 13, drive shaft 14, vehicle suspension components (not shown), differential 16 and other components of the vehicle 10 are mounted in a conventional well know manner.
As best shown in
The hydraulic unit housing 26 includes a longitudinally extending prime mover input shaft or mechanical drive shaft 41 connected to engine drive shaft 14 through a suitable torsional vibration dampening coupling 14a. Input shaft 41 (
As best illustrated in
As illustrated schematically in
More specifically, as illustrated in
Referring to
Referring now to
The connecting plate 25 of the connecting assembly 84 provides a hydraulic manifold and further includes fluid flow passages that include high pressure fluid flow passages 89a and 89b and pilot signal passages 90. The high pressure fluid outlet side of each hydraulic pump motor unit 42 and 43 includes a high pressure fluid outlet or flow tube 91 (
In this manner, the connecting plate 25 is a component of a connecting assembly 84 and provides a mounting platform for the pump motor units 42 and 43 and for the valves 52, 53, 54, and 55; provides support and bearings for the pump motor unit shafts 44 and 45; provides bearings for the transfer shaft 62 and support for the transfer shaft 62 and input shaft 41; provides a mounting platform for the planetary gear components 71; provides a wall for the hydraulic unit internal chamber 36 and for the planetary gear unit internal chamber 37; combines the hydraulic unit 23 and the planetary gear unit 24 into an integral unit; and provides a high pressure hydraulic manifold for the fluid connections between and among the high pressure accumulator 46, valves 52, 53, 54, and 55, setting pistons 48, 49, 50 and 51, and pump motor units 42 and 43 and their associated rotating piston groups and high pressure flow tubes 91, 92. The illustrated components in the hydraulic unit 23, such as for example the pump motor units 42 and 43, may be replaced with different components and used with the gear unit 24 or with a different gear unit. Similarly, the illustrated components in the gear unit 24, such as for example the planetary gear components 71 and drive gears, may be replaced with different components and used with the hydraulic unit 23 or with a different hydraulic unit. This enables the transmission 11 to be used in a wide variety of vehicles and applications.
As best illustrated in
Once the transmission 11 is assembled in the configuration illustrated in the drawings and described above, the transmission 11 is installed in the vehicle 10 in the lateral space between the frame rails 18 and in the longitudinal space between the prime mover drive shaft 14 and the differential drive shaft 17 (
Turning now the operation of the transmission 11, the transmission 11 operates in various modes under a wide variety of conditions. For example, the transmission 11 operates in various modes in response to vehicle operator accelerator pedal input to transmit power from the prime mover 13 and/or from stored energy in the high pressure accumulator 46 to the differential drive shaft 17 to propel the vehicle 10. Further, the transmission 11 operates in various modes in response to vehicle operator brake pedal input to capture energy from the vehicle 10 during braking of the vehicle 10 and to transmit the captured energy to the high pressure accumulator storage device 46 for later use. Still further, the transmission 11 operates in response to vehicle operator input to start the prime mover 13 using stored energy in the accumulator storage device 46 when the vehicle 10 is stationary.
To select among a virtually infinite array of the above described operating modes of the transmission 11, the displacement and pump or motor operating mode of pump motor units 42 and 43 may be changed and the isolation valves 54 and 55 may be opened or closed. For example, when the secondary unit 43 is to be used in a pumping mode during braking to charge the accumulator 46, an input provided to the pilot valve 55a may allow the isolation valve 55 to close. In this mode of operation, the isolation valve 55 for the secondary pump motor unit 43 may act as a check valve, so that the isolation valve 55 opens when pressure in the outlet tube 92 exceeds the pressure in the high pressure accumulator 46 to allow pressure from unit 43 to charge accumulator 46. The isolation valve 54 for the primary pump motor unit 42 may be generally opened when the vehicle 10 is moving, except closed when the secondary unit 43 is pumping during braking to prevent supply of fluid from the secondary unit 43 to the primary unit 42.
When the vehicle 10 is stationary, the isolation valve 54 for the primary unit 42 may be closed, to prevent unintended flow to the secondary unit 43 and unintended movement of the vehicle 10. The transmission 11 may also be used to start the engine 13, to eliminate the need for a conventional starter. For this mode, hydraulic fluid from accumulator 46 is supplied to primary pump motor unit 42 and isolated from secondary pump motor unit 43, so that unit 43 and its drive shaft 44 rotate to rotate gears 76, 77, 72 and 74 to rotate planet carrier 75 and transfer shaft 62 and input shaft 41 and drive shaft 14 to rotate and start prime mover engine 13 (
Further, the proportional control valves 52 and 53 adjust the displacement of the units 42 and 43 during both pumping and motoring modes. For example, when movement of vehicle 10 is initially started from a stopped position, fluid is supplied from accumulator 46 to secondary unit 43 and displacement of unit 43 is gradually increased to accelerate vehicle 10. As speed of the vehicle 10 increases and displacement of unit 43 increases, fluid pressure from accumulator 46 decreases and less stored energy is available to unit 43 to continue to drive vehicle 10. As the speed of the vehicle further increases, more power is transmitted mechanically directly from the engine 13 to driveshaft 17 through the planetary gearset 71, while less power is transmitted by the hydraulic pump motor units. By reducing the hydraulic power transmitted at higher vehicle speeds, the overall transmission efficiency is increased. Additionally, the displacements of pump motors 42 and 43 are steplessly adjusted to achieve a desired output shaft speed for a given input prime mover input shaft speed. The adjusting of displacement provides for an infinitely variable or stepless transmission ratio, which allows the prime mover 13 to be operated at its most efficient operating speed regardless of output shaft speed. Additionally, since there is no gear shifting, there is no interruption in power. Under this condition, displacement of units 42 and 43 may be set to zero, to minimize any drag or inefficiency caused by units 42 and 43. When vehicle 10 is to brake, secondary unit 43 is operated in a pumping mode and displacement of unit 43 is increased to pump more fluid into accumulator 46 and cause further braking resistance to the drive wheels 15 until the desired slower speed or stopped condition for the vehicle 10 is achieved. During operation of the transmission 11, the sealed hydraulic unit chamber 36 is maintained at a positive pressure of at least about 2 bar and preferably in the range of about 2 bar to about 6 bar, to prevent cavitation in the pump motor units 42 and/or 43 during pumping, while the sealed gear unit chamber 37 is maintained at about atmospheric pressure. Because the pump motor units 42 and 43 are disposed in chamber 36 which is the low pressure reservoir, separate low pressure conduits and connections between the low pressure reservoir and the pump motor units 42 and 43 are not required.
In this manner, the transmission 11 provides a hydromechanical powersplit transmission that captures and stores energy as high pressure fluid in accumulator 46 during vehicle braking and that uses that stored energy to propel the vehicle 10 or to start engine 13. Further, when the vehicle 10 is to be propelled when stored energy in accumulator 46 is depleted, a direct variable speed mechanical connection is provided from engine 14, through hydraulic unit 23 but without pumping or motoring displacement of the units 42 and 43, through the planetary gear set 71 and to the drive wheels 15.
Gear Unit Double SumpReferring now to FIGS. 1 and 7-9, the planetary gear unit housing 29 includes a front gear unit housing 29a and a rear gear unit housing 29b. The sealed interior chamber or sump 37 of the planetary gear unit 24 includes a front chamber or front sump 37a and a rear chamber or rear sump 37b. The primary hydraulic pump motor unit drive shaft 44 extends from the hydraulic side 25a, through the connecting plate 25, to the front chamber 37a, where its associated gear 76 is drivingly connected to the sun gear 72 through gear 77 (
Gear unit front housing 29a includes a longitudinally extending housing portion or wall 93 and a laterally extending generally planar housing portion or wall 94. Housing portion 94 provides a wall that separates sumps 37a and 37b and provides a common or shared wall for each sump 37a and 37b. An output drive shaft opening 95 extends longitudinally through housing portion or wall 94, and a bearing 96 in opening 95 supports output drive shaft 63. Gear unit rear housing 29b includes a longitudinally extending housing portion or wall 97 and a laterally extending generally planar housing portion or wall 98. The output drive shaft opening 63a extends longitudinally through housing portion or wall 98, and a bearing 100 in opening 63a supports output drive shaft 63.
When the motor vehicle 10 is not moving, the output shaft 63 and gears 79 and 78 and secondary pump motor unit drive shaft 45 are in a stationary condition and are not rotating. In this condition, the fluid level in the chambers or sumps 37a and 37b is approximately at a level indicated by dotted line 101a in
As illustrated in
Accordingly, the walls 93 and 94 of the front or first housing 29a define the front or first sump 37a. The rear or second housing 29b is connected to the first housing 29a and includes walls 97 and 98 that cooperate with the common wall 94 of the first housing 29a to define the rear or second sump 37b. A first set of rotatable gears 71 is disposed in the first sump 37a and has a stationary condition and a rotating condition. A second set of rotatable gears 78, 79 is disposed in the second sump 37b and has a stationary condition and a rotating condition. An input drive shaft 62 extends longitudinally into the first sump 37a and is rotatably connected to the first set of rotatable gears. An output drive shaft 63 extends longitudinally out of the second sump 37b and is rotatably connected to the second set of gears. The longitudinal axes 22 of the input and output drive shafts are substantially coaxial. A first hydraulic pump motor unit drive shaft 44 extends into the first sump 37a and is driving connected with the first set of rotatable gears. A second hydraulic pump motor unit drive shaft 45 extends longitudinally from end to end through the first sump 37a and into the second sump 37b and is drivingly connected with the second set of rotatable gears. The first and second hydraulic pump motor unit drive shafts are supported by bearings in walls 25, 94 and 98.
Spline ConnectionsThe gears and shafts described above are preferably secured together using a spline connection 160 illustrated in
The spline connection 160 includes an internal spline connector 161 on the gear 76 and a mating external spline connector 162 on the shaft 44. As best shown in
As best shown in
Continued movement of the gear 76 onto the shaft 44 to a second partially assembled position or configuration illustrated in
In this manner, the spline connection 161 includes an internal spline connector 161 and an external spline connector 162. At least one of the spline connectors 161 or 162, and preferably both, include a spline portion and a smooth centering portion. During assembly, the smooth centering portion of one of the spline connectors 161 or 162 cooperates with the spline portion of the other spline connector to align the connectors 161 and 162 while permitting rotating movement between the spline connectors 161 and 162. In the fully assembled configuration, the smooth centering portion of the one spline connector moves into registry with the smooth centering portion of the other spline connector to continue to maintain alignment and reduce relative movement between the spline connectors.
CONCLUSIONThe principles, embodiments and operation of the present invention are described in detail herein with reference to the accompanying drawings but are not to be construed as being limited to the particular illustrative forms disclosed. It will thus become apparent to those skilled in the art that various modifications of the principles, embodiments and operation herein can be made without departing from the spirit or scope of the invention.
Claims
1. A spline connection (160) comprising an internal spline connector (161) and an external spline connector (162),
- each of the spline connectors having a spline portion (166, 174),
- at least one of the spline connectors having a substantially smooth centering portion (168) longitudinally substantially adjacent its spline portion,
- the spline connectors having a first partially assembled configuration in which the spline portion (174) of one of the spline connectors is radially aligned with and engages with sliding contact the smooth centering portion (168) of the other spline connector,
- the spline connectors having a second partially assembled configuration in which the spline portions of each of the spline connectors are at least partially radially aligned with one another.
2. A spline connection as set forth in claim 1, wherein the spline connectors have a fully assembled configuration in which the entire longitudinal extent of the spline portion of the one of the spline connectors is radially aligned with at least a portion of the longitudinal extent of the spline portion of the other spline connector.
3. A spline connection as set forth in any of preceding claims 1-2, wherein each of the spline connectors includes a substantially smooth generally cylindrical centering portion substantially adjacent its spline portion.
4. A spline connection as set forth in claim 3, wherein the centering portion of the internal spline connector is on one side of its spline portion when the spline connectors are in the first and second partially assembled positions, and the centering portion of the external spline connector is on the same side of its spline portion when the spline connectors are in the first and second partially assembled positions.
5. A spline connection as set forth in any of preceding claims 3-4, wherein the centering portions are only partially radially aligned and the spline portions are only partially radially aligned when the spline connection is in its second partially assembled configuration.
6. A spline connection as set forth in any of preceding claims 1-5, wherein each of the spline portions is generally cylindrical.
7. A spline connection as set forth in any of preceding claims 1-6, wherein the one spline connector is the internal spline connector.
8. A spline connection as set forth in claim 7, wherein the substantially smooth centering portion of the internal spline connector guides the spline portion of the external spline connector into circumferential and longitudinal alignment with the spline portion of the internal spline connection as the spline connectors are displaced from a disassembled configuration to the first partially assembled configuration.
9. A spline connection as set forth in any of preceding claims 7-8, wherein the internal spline connector has a longitudinal extent, and the spline portion of the internal spline connector has a longitudinal extent of at least about 30% of the longitudinal extent of the internal spline connector.
10. A spline connection as set forth in claim 9, wherein the spline portion of the internal spline connector has a longitudinal extent of between about 50% and 80% of the longitudinal extent of the internal spline connector.
11. A spline connection as set forth in any of preceding claims 7-10, wherein the centering portion of the internal spline connector has a longitudinal extent, and the longitudinal extent of the centering portion of the internal spline connector is at least about 10% of the longitudinal extent of the internal spline connector.
12. A spline connection as set forth in claim 11, wherein the centering portion of the internal spline connector has a longitudinal extent of between about 20% and 60% of the longitudinal extent of the internal spline connector.
13. A spline connector as set forth in any of preceding claims 7-12, wherein the other spline connector is an external spline connector having a spline portion and a generally smooth substantially cylindrical portion adjacent its spline portion.
14. A spline connection as set forth in any of preceding claims 1-13, wherein the internal spline connector is on a bore (164) in a gear (76), the external spline connector is on a shaft (44), and the gear and the shaft are in a sump (37) in a hydromechanical transmission (11).
Type: Application
Filed: Jan 25, 2013
Publication Date: Nov 7, 2013
Applicant: PARKER-HANNIFIN CORPORATION (Cleveland, OH)
Inventors: John Michael Loeffler (Olive Branch, MS), Daniel James Paisley (Lexington, KY), Matthew James Rommel (Independence, KY)
Application Number: 13/749,746
International Classification: F16D 1/06 (20060101);