Hybrid transmission with dual drive pumps

Abstract

A hybrid electric transmission with a dual drive pump is disclosed. In the pump system of the hybrid electric transmission, the pump is alternately driven by the faster rotating one of the input shaft and the output shaft. The input shaft and the output shaft are coaxial. A sprocket and chain transfer power from the axis of the input shaft and the output shaft to the axis of the pump. The drive sprocket is selectively coupled to the input shaft by a first one-way clutch and selectively coupled to the output shaft by a second one-way clutch. Two optional one-way clutch and bearing arrangements are disclosed.

Description

Technical Field

[0001] The present disclosure relates to the field of hybrid electric vehicles. More specifically, the present disclosure relates to an engine driven off-axis pump drive system designed to maintain pump drive while the vehicle is electrically propelled. Background Art

[0002] Many vehicles are used over a wide range of vehicle speeds, including both forward and reverse motion. However, certain types of engines can only operate efficiently over a narrow speed range. Therefore, transmissions that can efficiently transmit power at various speed ratios are often employed. When the vehicle is at low speeds, the transmission is typically operated at a high speed ratio, thereby multiplying the engine torque to improve acceleration. At high vehicle speeds, operating the transmission at a low speed ratio allows for engine speeds that are associated with quiet, fuel-efficient cruising.

[0003] Transmission components such as gears and bearings require lubrication. Typically, the transmission housing contains a supply of lubricating fluid, which tends to collect in the lowest part of the housing, known as the sump. A pump can be used to distribute the lubricating fluid from the sump to each component that requires lubrication.

[0004] To reduce fuel consumption, some vehicles include hybrid powertrains that utilize energy storage to supplement the power produced by the internal combustion engine. These powertrains allow the vehicle to operate with the engine off for a portion of the time, and operate the vehicle at the engine's more efficient torque level for the remainder of the time. Hybrid powertrains are also able to capture and subsequently use energy that would otherwise be consumed by the braking system. Summary of the invention

[0005] A hybrid power transmission includes an input shaft, an output shaft, a motor, a drive sprocket, a driven sprocket, a chain and a pump. The input shaft is adapted to be fixed to an internal combustion engine. The output shaft is coaxial with the input shaft and is drivably connected to a differential. The motor is configured to propel the output shaft when the input shaft is stationary. The drive sprocket is selectively coupled to the input shaft through a first one-way clutch and selectively coupled to the output shaft through a second one-way clutch. The drive sprocket may be supported by the input shaft via a combined bearing and one-way clutch assembly. In some embodiments, the second one-way clutch may act on a radially outer surface of the drive sprocket and a radially inner surface of the output shaft. In some embodiments, the drive sprocket may include an internal member splined to an external member. The internal member may be selectively coupled to the input shaft while the external member is selectively coupled to the output shaft. The chain engages both the drive sprocket and the driven sprocket. The pump is drivably connected to the driven sprocket.

[0006] In some embodiments, a hybrid power transmission includes a first sprocket, a second sprocket, a first motor, and a pump. The first sprocket and the second sprocket are drivably connected to each other by a chain. The first sprocket is selectively coupled to an input shaft by a first one-way clutch and selectively coupled to an output shaft by a second one-way clutch. The first motor is configured to propel the output shaft when the input shaft is stationary. The pump is driven by the second sprocket. The hybrid power transmission may also include a simple planetary gear set having a sun gear fixedly coupled to the second motor, a gear carrier fixedly coupled to the input shaft, and a ring gear drivably coupled to the output shaft and drivably coupled to the first motor.

[0007] A pump system for a hybrid power transmission includes a first sprocket, a second sprocket and a pump. The first sprocket and the second sprocket are drivably connected to each other by a chain. The first sprocket is selectively coupled to an input shaft by a first one-way clutch and selectively coupled to an output shaft by a second one-way clutch. The first sprocket may be supported by the input shaft via a combined bearing and one-way clutch assembly. In some embodiments, the second one-way clutch may act on a radially outer surface of the first sprocket and a radially inner surface of the output shaft. In some embodiments, the first sprocket may include an internal member splined to an external member. The internal member may be selectively coupled to the input shaft while the external member is selectively coupled to the output shaft. The input shaft is adapted to be connected to an internal combustion engine and the output shaft is adapted to drive wheels. The pump is driven by the second sprocket. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a cross-sectional view of a hybrid vehicle powertrain.

[0009] Figure 2 Suitable for use in Figure 1 Schematic diagram of the pump drive mechanism in a hybrid vehicle powertrain.

[0010] Figure 3 yes Figure 2 sectional view of a first embodiment of a pump drive mechanism.

[0011] Figure 4 yes Figure 2 sectional view of a second embodiment of a pump drive mechanism. DETAILED DESCRIPTION

[0012] As required, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the present invention that may be implemented in various and alternative forms. The drawings are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to utilize the present invention in various ways.

[0013] Figure 1 is a cross-sectional view of a hybrid transmission. Mechanical power from an internal combustion engine is supplied at an input shaft 10. The input shaft 10 is fixedly coupled to a gear carrier of a simple planetary gear set 12. The rotor 14 of the first electric machine is fixedly coupled to the sun gear of the planetary gear set 12. The output shaft 16 is fixedly coupled to the ring gear of the planetary gear set 12. Power is transmitted from the output shaft 16 to the differential 18 via an intermediate shaft 20. The rotor 22 of the second electric machine is coaxially located with the input shaft 10 and the output shaft 16 and also drives the intermediate shaft 20, but drives the intermediate shaft 20 at a different gear ratio than the output shaft 16.

[0014] The stator of each of the two motors is electrically connected to an inverter. The inverter controls the current so that the desired level of torque is applied to the corresponding rotor. In some operating modes, the motor absorbs electricity and produces mechanical power. In other operating modes, the motor absorbs mechanical power and produces electricity. Any net electricity generated by the two motors is stored in the battery. In other operating modes, the battery provides electricity. In some operating modes, the internal combustion engine can be turned off and all power is provided by driving the second motor through the battery.

[0015] Bearings and meshing gears require lubrication to operate efficiently and avoid accelerated wear. Lubricants also absorb heat from components. Lubricants naturally drain to the lowest area of ​​the transmission housing (which is called the sump). Some lubricant can be distributed from the sump to the various components by splashing. However, it is preferred to distribute the lubricant to the components in a systematic manner. Typically, the lubricant is distributed by a pump driven by the input shaft. However, when the internal combustion engine is not running, the input shaft does not rotate. Unless the lubricant can be effectively distributed during the pure battery operating mode, the controller must limit the operating duration in this mode, which reduces the fuel economy potential of the powertrain.

[0016] Figure 2 Shows Figure 1The invention relates to a pump drive mechanism of a transmission device. When the input shaft 10 rotates faster than the output shaft 16, the drive sprocket 24 is driven by the input shaft via the first one-way clutch 26. When the output shaft 16 rotates faster than the input shaft 10, the drive sprocket 24 is driven by the output shaft via the second one-way clutch 28. The drive sprocket 24 is supported to rotate on the same axis as the rotation axis of the input shaft 10 and the output shaft 16. The driven sprocket 30 is supported to rotate about another axis. The chain 32 is wound around the drive sprocket 24 and the driven sprocket 30, engaging with the teeth on each sprocket so that the rotational speeds of the two sprockets are proportional. The pump 34 is fixedly coupled to the driven sprocket 30.

[0017] Figure 3 A cross-sectional view of a drive sprocket support of a first embodiment of a pump drive mechanism is shown. One end of the output shaft 16 is supported by the transmission housing 40 via a ball bearing 42. One end of the input shaft 10 is supported by the output shaft 16 via a ball bearing 44. A cover 46 and a seal 48 enclose the input end of the transmission at the input shaft. The drive sprocket 24 is radially supported by the input shaft 10 via a combined bearing and one-way clutch assembly 50. The combined bearing and one-way clutch assembly 50 includes three sets of balls. The outer race is a ring around the outer balls, which acts as a bearing. The outer race has an inclined surface around the middle set of balls, so that whenever the sprocket 24 rotates slower than the input shaft 10 instantaneously, the balls are squeezed between the shaft and the outer race. After a slight relative displacement, this squeezing combines the sprocket 24 with the shaft 10 so that they rotate at the same speed. Positive rotation of the drive sprocket 24 relative to the input shaft 10 relieves the squeezing, thereby allowing unrestricted relative rotation in this direction. The drive sprocket 24 is axially located by the sleeve 52. The one-way clutch 54 is configured similarly to the interior of the assembly 50 to allow the drive sprocket 24 to rotate faster than the output shaft 16 and to couple them together in response to slight relative rotation in opposite directions.

[0018] Figure 4 A cross-sectional view of a drive sprocket support of a second embodiment of a pump drive mechanism is shown. The drive sprocket 24' is radially supported by the output shaft 16 via a combined bearing and one-way clutch assembly 56. The sprocket hub 58 is radially supported by the input shaft 10 via a combined bearing and one-way clutch assembly 50. The sprocket hub 58 and sprocket 24' are splined together, which forces them to rotate at the same speed but accommodates slight differences in the axis of rotation. In this way, concentricity tolerances are less critical.

[0019] Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the present invention. More specifically, the words used in the specification are descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of the present invention. In addition, the features of the embodiments of each implementation may be combined to form further embodiments of the present invention.

Claims

1. A hybrid power transmission device, comprising: an input shaft adapted to be secured to an internal combustion engine; an output shaft, coaxial with the input shaft and drivably connected to the differential; a motor configured to propel the output shaft when the input shaft is stationary; a drive sprocket selectively coupled to the input shaft via a first one-way clutch and selectively coupled to the output shaft via a second one-way clutch; Driven sprocket; a chain engaging both the drive sprocket and the driven sprocket; A pump is provided to which the driven sprocket is drivably connected.

2. The hybrid power transmission device according to claim 1, wherein: The drive sprocket is supported by the input shaft via a combined bearing and one-way clutch assembly.

3. The hybrid power transmission device as claimed in claim 2, wherein: The second one-way clutch acts on the radially outer surface of the drive sprocket and on the radially inner surface of the output shaft.

4. The hybrid power transmission device as claimed in claim 1, wherein: The drive sprocket includes an inner member splined to an outer member, the inner member selectively coupled to the input shaft by a first one-way clutch, and the outer member selectively coupled to the output shaft by a second one-way clutch.

5. The hybrid power transmission device as claimed in claim 4, wherein: The inner member is supported by the input shaft via a first combined bearing and one-way clutch assembly.

6. The hybrid power transmission device as claimed in claim 4, wherein: The outer member is supported by the output shaft via a second combined bearing and one-way clutch assembly.

7. A hybrid power transmission device comprising: a first sprocket and a second sprocket driveably connected to each other by a chain, the first sprocket being selectively coupled to the input shaft by a first one-way clutch and selectively coupled to the output shaft by a second one-way clutch; a first electric machine configured to propel the output shaft when the input shaft is stationary; Pump, driven by the second sprocket.

8. The hybrid powertrain of claim 7, further comprising: A simple planetary gear set has a sun gear fixedly coupled to the second electric machine, a carrier fixedly coupled to the input shaft, and a ring gear drivably connected to the output shaft and drivably connected to the first electric machine.

9. The hybrid power transmission device as claimed in claim 7, wherein: The first sprocket is supported by the input shaft via a combined bearing and one-way clutch assembly.

10. The hybrid powertrain of claim 9, wherein: The second one-way clutch acts on the radially outer surface of the first sprocket and on the radially inner surface of the output shaft.

11. The hybrid powertrain of claim 7, wherein: The first sprocket includes an inner member splined to an outer member, the inner member selectively coupled to the input shaft via a first one-way clutch, and the outer member selectively coupled to the output shaft via a second one-way clutch.

12. A pump system for a hybrid power transmission, comprising: a first sprocket and a second sprocket driveably connected to each other by a chain, the first sprocket being selectively coupled to an input shaft by a first one-way clutch and selectively coupled to an output shaft by a second one-way clutch, the input shaft being adapted to be connected to an internal combustion engine and the output shaft being adapted to drive wheels; Pump, driven by the second sprocket.

13. The pump system for a hybrid powertrain according to claim 12, wherein: The first sprocket is supported by the input shaft via a combined bearing and one-way clutch assembly.

14. The pump system for a hybrid powertrain according to claim 13, wherein: The second one-way clutch acts on the radially outer surface of the first sprocket and on the radially inner surface of the output shaft.

15. The pump system for a hybrid powertrain according to claim 12, wherein: The first sprocket includes an inner member splined to an outer member, the inner member selectively coupled to the input shaft via a first one-way clutch, and the outer member selectively coupled to the output shaft via a second one-way clutch.

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