Gearbox with integrated power take-off

Abstract

Transmission (10) of a drive train of a motor vehicle, wherein the transmission (10) comprises: a gearbox housing (12); a transmission input shaft (14), a transmission shaft (22) and a first and second transmission output shaft (24), wherein each of the shafts (14, 22, 24) is rotatably mounted through the transmission housing (12), and wherein an axis of the transmission shaft (22) is parallel to an axis of the transmission input shaft (14); a first and second transmission element (16, 20), wherein the first transmission element (16) is connected to the transmission input shaft (14) for common rotation, the second transmission element (20), which may be designed as a driven sprocket or as a driven gear, is formed integrally with the transmission shaft (22) to form a driven transmission element, the second transmission output shaft (24) is arranged coaxially to the transmission shaft (22) and is partially covered by it, and the first transmission output shaft is arranged coaxially with the transmission input shaft (14); a continuous transmission element (30) that engages with each of the first and second transmission elements (16, 20); a hydraulic piston coupling (26) for selectively connecting the transmission shaft (22) to the second transmission output shaft (24); wherein the second transmission output shaft (24) is designed to accommodate an auxiliary assembly (62), wherein the transmission shaft (22) is rotatably mounted through the transmission housing (12) via a roller bearing (32), the second transmission output shaft (24) is rotatably mounted at a first end (25) through the transmission housing (12) via a roller bearing (36) and is rotatably mounted and partially covered at a second end (27) through the transmission shaft (22) and has a serrated inner surface (29) at the first end (25), wherein the hydraulic piston coupling (26) comprises an outer piston housing element (38), an inner piston housing element (40), a compensating piston (42), a hydraulic piston (44), a return spring (46), a ring element (48) and a plurality of interlocking coupling plates (50), wherein the outer piston housing element (38) is integrated into the driven transmission element (20), the inner piston housing element (40) is integrated into the transmission shaft (22),the compensating piston (42) is arranged between the outer piston housing element (38) and the inner piston housing element (40) and forms a piston chamber (52), the hydraulic piston (44) is arranged between the outer piston housing element (38) and the compensating piston (42) and forms a hydraulic fluid actuation chamber (54) with the outer piston housing element (38), the return spring (46) is arranged between the compensating piston (42) and the hydraulic piston (44), thereby providing a return force that pushes the hydraulic piston (44) towards the outer piston housing element (38), the ring element (48) is serrated with the outer piston housing element (38), the plurality of interlocking coupling plates (50) comprises a first set of coupling plates (56) having serrated teeth on the outer circumference of the coupling plates, and a second set of coupling plates (58) having serrated teeth on the inner circumference of the coupling plates,the first set of coupling plates (56) is splined with the ring element (48), the second set of coupling plates (58) is splined with the second transmission output shaft (24) for common rotation, , wherein the transmission (10) further comprises a clutch actuation hydraulic fluid circuit (28) for selectively transmitting hydraulic pressure fluid to the hydraulic fluid actuation chamber (54) of the hydraulic piston clutch (26).

Description

[0001] The present disclosure relates to vehicle powertrains and, more particularly, to transmissions having multiple power delivery means.

[0002] Most transmission types include an input shaft, an output shaft, a plurality of gear assemblies, interconnecting members, shafts, and torque-transmitting mechanisms, among other mechanical elements. The various torque-transmitting mechanisms are employed to selectively transfer torque from one rotating element to another, or from a rotating element to a stationary element, to achieve a specific speed ratio between the input and output shafts. The output shaft drives a final drive assembly, which may further change speed ratios between the transmission output shaft and the axle. The output shaft may also drive a separate drive accessory, such as a power take-off assembly or other type of equipment that requires torque to operate.

[0003] DE 101 52 859 A1 discloses a transmission comprising: a transmission housing, a transmission input shaft, a transmission shaft, and first and second transmission output shafts, each of the shafts being rotatably supported by the transmission housing, and an axis of the transmission shaft being parallel to an axis of the transmission input shaft, a drive gear, and a driven gear, the second output shaft being arranged coaxially with and partially covered by the transmission shaft, and an intermediate gear meshing with the drive gear and the driven gear. The second output shaft is configured to receive an auxiliary assembly. A torque-transmitting mechanism is also provided that selectively connects the transmission shaft to the second output shaft.

[0004] From DE 601 04 011 T2 a transmission is known which comprises: a transmission housing, a transmission input shaft, a transmission shaft and a first and second transmission output shaft, wherein each of the shafts is rotatably supported by the transmission housing, and wherein an axis of the transmission shaft is parallel to an axis of the transmission input shaft, a drive sprocket and a driven sprocket, wherein the second output shaft is arranged coaxially with the transmission shaft and is partially covered thereby, and the first output shaft is arranged coaxially with the transmission input shaft, a chain which engages with the drive sprocket and the driven sprocket, wherein the second output shaft is configured to receive an auxiliary assembly, wherein the second transmission output shaft is rotatably supported at a first end by the transmission housing and is rotatably supported at a second end by the transmission shaft and is partially covered thereby.A torque transmitting mechanism may also be provided that selectively connects the transmission shaft to the second output shaft.

[0005] US 6 854 541 B2 teaches a transmission comprising: a transmission housing, a transmission input shaft, a transmission shaft, and first and second transmission output shafts, each of the shafts being rotatably supported by the transmission housing. A hydraulic piston clutch is used to selectively connect the second transmission output shaft to a first shaft of a two-speed twin-shaft transmission. The second shaft of the twin-shaft transmission is configured to receive an auxiliary assembly. The second transmission output shaft is rotatably supported by the transmission housing via roller bearings, and the first shaft of the twin-shaft transmission is rotatably supported at a first end by the transmission housing via a roller bearing and rotatably supported and partially covered at a second end by the second transmission output shaft.The hydraulic piston clutch includes an outer, cup-shaped piston housing member, a hydraulic piston, a return spring, a ring member disposed on the second transmission output shaft, and a plurality of intermeshing clutch plates. The hydraulic piston is disposed between the outer piston housing member and the first shaft and forms a hydraulic fluid actuation chamber with the outer piston housing member. The return spring is disposed between the ring member and the hydraulic piston.The plurality of intermeshing clutch plates includes a first set of clutch plates having splines on the outer periphery of the clutch plates and a second set of clutch plates having splines on the inner periphery of the clutch plates, the first set of clutch plates being splined to the outer cup-shaped piston housing member, the second set of clutch plates being splined for common rotation with the second output shaft, the transmission further including a hydraulic fluid circuit for selectively communicating pressurized hydraulic fluid to the hydraulic fluid actuation chamber of the hydraulic piston clutch.

[0006] It is the object of the invention to provide an alternative hydraulic piston clutch in a transmission with a second output shaft for receiving an auxiliary assembly.

[0007] This object is achieved by a transmission having the features of claim 1.

[0008] Advantageous developments of the invention are specified in the dependent claims.

[0009] The invention is described below by way of example with reference to the drawing: Fig. 1 is a cross-sectional view of a portion of a transmission according to the principles of the present invention.

[0010] With reference to Fig. 1, a portion of a transmission for a motor vehicle is generally indicated by reference numeral 10. The transmission 10 is generally a part of a vehicle's driveline that includes an engine (not shown) connected to the transmission 10. The engine may be a conventional gasoline, diesel, or flex-fuel internal combustion engine, a hybrid engine, an electric motor, or any other type of prime mover without departing from the scope of the present disclosure. The engine provides drive torque to the transmission 10 through, for example, a flexplate or other interconnecting device, or a launching device such as a hydrodynamic device or launch clutch (not shown).

[0011] The transmission 10 may be a continuously variable transmission with a variable diameter disc or half-disc drive (CVT), a multi-speed planetary gear set automatic transmission, or a manual transmission without departing from the scope of the invention. The transmission 10 includes a typically cast metal housing 12 that encloses and protects the various components of the transmission 10. The transmission housing 12 includes a variety of openings, passageways, shoulders, and flanges that position and support these components. Generally speaking, the transmission 10 includes a transmission input shaft 14 and a first transmission output shaft (not shown).Optionally connected between the transmission input shaft 14 and the first transmission output shaft are a speed change device, a pulley assembly or continuously variable unit, and a torque transfer assembly, which cooperate to provide forward and reverse speed or forward and reverse gear ratios between the transmission input shaft 14 and the first transmission output shaft. The transmission input shaft 14 is operatively connected to the prime mover (not shown) through the starting device (not shown) and receives input torque or power from the prime mover. The transmission output shaft is preferably connected to a final drive unit (not shown). The first transmission output shaft provides drive torque to the final drive unit. The final drive unit may include a differential, axle shafts, and road gears (not shown).

[0012] The transmission 10 further includes an off-axis input and clutch assembly 18. The input and clutch assembly 18 includes a drive sprocket 16, a driven sprocket 20, a transfer shaft 22, a second output shaft 24, a torque-transmitting mechanism or disconnect clutch 26, a clutch actuating hydraulic fluid circuit 28, and a continuous transfer member 30. The driven shaft 22 is rotatably supported by the transmission housing 12 via a first bearing 32. The driven sprocket 20 is connected for common rotation with the driven shaft 22 or, alternatively, is integrated with the driven shaft 22 as a singular rotating member. The driven sprocket 20 is axially aligned with a transmission drive sprocket 16, which is connected for common rotation with the input shaft 14.The continuous transmission member 30 engages each of the driven sprocket 20 and the drive sprocket 16, thereby transmitting torque from the input shaft 14 to the driven shaft 22. As shown in FIG. Fig. 1, the continuous transmission element 30 is a chain or belt. However, without departing from the scope of the invention, the continuous transmission element 30 may also be replaced by an idler gear, and the drive and driven sprockets 16, 20 may be replaced by a drive and driven gear supported by the transmission housing 12 and meshingly engaged with the idler gear.

[0013] The second output shaft 24 is coaxial with the driven shaft 22, is rotatably supported at a first end 25 by the gear housing 12 via a second bearing 36, is partially covered and rotatably supported at a second end 27 by the driven shaft 22 and has a splined inner surface 29 at the first end 25. The hydraulic piston clutch 26 is arranged coaxially with the driven shaft 22 and the second output shaft 24 and selectively connects the driven shaft 22 and the driven sprocket 20 to the second output shaft 24. The hydraulic piston clutch 26 includes a first or outer piston housing member 38, a second or inner piston housing member 40, a balance piston 42, a hydraulic piston 44, a return spring 46, a ring member 48, and a plurality of intermeshing clutch plates 50. More specifically, the outer piston housing member 38 is integrated with the driven sprocket 20.Similarly, the inner piston housing member 40 is integrated with the driven shaft 22. The radial piston housing member or balance piston 42 is disposed between the outer piston housing member 38 and the inner piston housing member 40, forming a piston chamber 52. The hydraulic piston 44 is disposed between the outer piston housing member 38 and the balance piston 42, forming with the outer piston housing member 38 a hydraulic fluid actuation chamber 54. The return spring 46 is disposed between the balance piston 42 and the hydraulic piston 44, providing a return force urging the hydraulic piston 44 toward the outer piston housing member 38.

[0014] The ring member 48 is splined or otherwise connected for common rotation with the outer piston housing member 38. The plurality of intermeshing clutch plates 50 includes a first set of clutch plates 56 having splines on the outer periphery of the clutch plates and a second set of clutch plates 58 having splines on the inner periphery of the clutch plates. The first set of clutch plates 56 is splined to the ring member 48. The second set of clutch plates 58 is splined for common rotation with the second output shaft 24. Upon selective pressurization of the hydraulic fluid actuation chamber 54, the hydraulic piston 44 axially translates to contact and compress the plurality of clutch plates 50, thereby locking the first set of clutch plates 56 into common rotation with the second set of clutch plates 58.The result is a common rotation and torque transmission from the driven sprocket 20 to the second output shaft 24.

[0015] The clutch actuation hydraulic fluid circuit 28 includes a number of hydraulic fluid passages 60 disposed within the transmission housing 12, the driven shaft 22, and the driven sprocket 20. The clutch actuation hydraulic fluid circuit 28 communicates with a hydraulic valve (not shown) and a hydraulic pressure source (not shown) to selectively supply pressurized hydraulic fluid to the hydraulic piston clutch 26.

[0016] The transmission 10 further comprises a torque-absorbing means 62. Fig.1 illustrates a hydraulic fluid pump 62 as the torque-absorbing means 62. However, other torque-absorbing means 62 may be employed without departing from the scope of the invention. For example, a transmission housing having a propeller shaft for driving a mechanical device may be used.

Claims

[1] Transmission (10) of a drive train of a motor vehicle, the transmission (10) comprising: a gear housing (12); a transmission input shaft (14), a transmission shaft (22) and first and second transmission output shafts (24), each of the shafts (14, 22, 24) being rotatably supported by the transmission housing (12), and an axis of the transmission shaft (22) being parallel to an axis of the transmission input shaft (14); a first and second transmission element (16, 20), wherein the first transmission element (16) is connected for common rotation with the transmission input shaft (14), the second transmission element (20), which may be designed as a driven sprocket or as a driven gear, is formed integrally with the transmission shaft (22) to form a driven transmission element, the second transmission output shaft (24) is arranged coaxially with the transmission shaft (22) and is partially covered by it, and the first transmission output shaft is arranged coaxially with the transmission input shaft (14); a continuous transmission element (30) engaging each of the first and second transmission elements (16, 20); a hydraulic piston clutch (26) for selectively connecting the transmission shaft (22) to the second transmission output shaft (24); wherein the second transmission output shaft (24) is configured to receive an auxiliary assembly (62), wherein the transmission shaft (22) is rotatably supported by the transmission housing (12) via a roller bearing (32), the second transmission output shaft (24) is rotatably supported at a first end (25) by the transmission housing (12) via a roller bearing (36) and is rotatably supported and partially covered by the transmission shaft (22) at a second end (27) and has a splined inner surface (29) at the first end (25), wherein the hydraulic piston clutch (26) comprises an outer piston housing member (38), an inner piston housing member (40), a balance piston (42), a hydraulic piston (44), a return spring (46), a ring member (48), and a plurality of intermeshing clutch plates (50), wherein the outer piston housing member (38) is integrated into the driven transmission member (20), the inner piston housing member (40) is integrated into the transmission shaft (22),the balance piston (42) is arranged between the outer piston housing element (38) and the inner piston housing element (40) and forms a piston chamber (52), the hydraulic piston (44) is arranged between the outer piston housing element (38) and the balance piston (42) and forms a hydraulic fluid actuation chamber (54) with the outer piston housing element (38), the return spring (46) is arranged between the balance piston (42) and the hydraulic piston (44), thereby providing a restoring force that urges the hydraulic piston (44) toward the outer piston housing element (38), the ring element (48) is splined to the outer piston housing element (38), the plurality of intermeshing clutch plates (50) comprises a first set of clutch plates (56) having splines on the outer periphery of the clutch plates, and a second set of clutch plates (58) having splines on the inner periphery of the clutch plates,the first set of clutch plates (56) is splined to the ring member (48), the second set of clutch plates (58) is splined for common rotation with the second transmission output shaft (24), , wherein the transmission (10) further comprises a clutch actuation hydraulic fluid circuit (28) for selectively communicating pressurized hydraulic fluid to the hydraulic fluid actuation chamber (54) of the hydraulic piston clutch (26). [2] The transmission (10) of claim 1, wherein the first transmission element (16) is a drive sprocket, the second transmission element (20) is a driven sprocket, and the continuous transmission element (30) is a chain. [3] The transmission (10) of claim 1, wherein the first transmission member (16) is formed integrally with the transmission input shaft (14) to form a drive transmission member. [4] The transmission (10) of claim 1, wherein the first transmission element (16) is a drive gear, the second transmission element (20) is a driven gear, and the continuous transmission element (20) is an idler gear.

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