Transmission unit and powertrain

Abstract

The clutch unit (20) includes a coupling element (23) that drivingly couples an output shaft (13) of an engine (10) and an input shaft (16) of a hydraulic pump (15) that is driven by driving force of the engine (10), and a motor generator (18) that generates driving force independently of the engine (10), the motor generator (18) being disposed away from the coupling element (23) as viewed in an axial direction of the output shaft (13).

Description

Technical Field

[0001] This invention relates to a transmission unit and a power system. This application claims priority based on Japanese Patent Application No. 2020-210699, filed on December 18, 2020, the contents of which are incorporated herein by reference. Background Technology

[0002] For example, patent documents 1 and 2 disclose a technology in which a hydraulic clutch 14 is provided between the engine 10 and the electric motor 15 in the drive system of a hybrid vehicle, and the switching between engine driving mode and EV driving mode is made smooth by controlling the disconnection of the clutch 14. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-093638 Patent Document 2: Japanese Patent Application Publication No. 2020-093639 Summary of the Invention (a) Technical problems to be solved

[0004] In the aforementioned prior art, the installation of a second drive source, such as an electric motor, on top of a first drive source, such as an engine, is not disclosed. However, if a second drive source can be installed on an existing first drive source to achieve hybridization, a highly versatile power system can be constructed.

[0005] Therefore, the present invention provides a transmission unit and power system that can efficiently integrate a second drive source by setting a first drive source on top of a second drive source. (II) Technical Solution

[0006] A first aspect of the present invention is a transmission unit comprising: a connecting element that connects in a transmissive manner to an output shaft of a drive source and an input shaft of a driven device driven by the driving force of the drive source; and a second drive source that generates a driving force independently of the drive source, wherein the second drive source is disposed away from the connecting element when viewed from the axial direction of the output shaft.

[0007] Regarding the second aspect of the present invention, in the first aspect described above, the second driving source is an electric generator having a second output shaft offset relative to the output shaft, and a transmission mechanism is provided between the output shaft and the second output shaft, the transmission mechanism being capable of increasing the driving force of the output shaft and transmitting it to the second output shaft.

[0008] Regarding the third aspect of the present invention, in the second aspect described above, a transmission mechanism capable of transmitting power is provided between the output shaft and the second output shaft, and a transmission housing for housing the transmission mechanism is provided. A rotating body cover for housing a rotating body that rotates integrally with the output shaft is provided at the drive source side of the transmission housing, and the second drive source is disposed at the drive source side of the transmission housing away from the rotating body cover.

[0009] Regarding the fourth aspect of the present invention, in the third aspect described above, the transmission housing includes a flat housing portion, which is formed such that the width in the axial direction is narrower than the width in the orthogonal direction orthogonal to the axial direction, and is disposed in the axial direction between the drive source and the driven device.

[0010] Regarding the fifth aspect of the present invention, in the fourth aspect described above, the rotating body cover and the second driving source are disposed at the drive source side of the flat housing portion.

[0011] Regarding the sixth aspect of the present invention, in any of the second to fifth aspects described above, the connecting element includes a clutch that disconnects the power transmission between the drive source and the driven device, wherein the second drive source is the electric generator, which is connected to the drive source in a transmissive manner via the clutch, and the second drive source is not connected to the driven device in a transmissive manner via the clutch.

[0012] The seventh aspect of the present invention is a power system comprising the transmission unit, the drive source, and the driven device described in any of the first to sixth aspects. (III) Beneficial Effects

[0013] According to the first and seventh embodiments of the present invention, by offsetting the second drive source relative to the connecting element of the drive source and the driven device, the increase in the axial width of the transmission unit and the power system having the transmission unit can be suppressed compared to the case where the second drive source and the drive source are coaxially arranged. In addition, compared to the case where the second drive source is clamped between the output shaft of the drive source and the input shaft of the driven device, the second drive source is easier to access from the outside, which improves maintainability.

[0014] According to a second aspect of the present invention, since the driving force of the driving source can be increased and transmitted to the second driving source, the power generation of the electric generator can be increased. In addition, since the driving force of the electric generator is reduced and transmitted to the driving source and the driven device, the output of the electric generator can be suppressed. Therefore, it is possible to achieve miniaturization and lightweighting of electric generators.

[0015] According to the third aspect of the present invention, the rotating body cover and the second drive source can be efficiently configured at the drive source side of the transmission housing, thereby enabling miniaturization of the transmission unit.

[0016] According to a fourth aspect of the present invention, the transmission housing has a flat housing portion that has a suppressed axial width and is disposed between the drive source and the driven device, so that the transmission unit can be configured without significantly separating the drive source and the driven device.

[0017] According to the fifth aspect of the present invention, the rotating body cover and the second drive source are concentrated in the drive source side of the flat housing portion, thus making the transmission unit more compact compared to the case where the rotating body cover and the second drive source are respectively arranged on both sides of the axial direction of the flat housing portion.

[0018] According to a sixth aspect of the present invention, if the clutch is engaged, the driven device can be driven by the drive source, and the electric generator can be driven to generate electricity. In this case, if the electric generator is put into operation, the drive source can be assisted by the electric generator. Furthermore, if the clutch is disengaged and the electric generator is in operation, the driven device can be driven solely by the electric generator even when the drive source is stopped. Attached Figure Description

[0019] Figure 1 This is an explanatory diagram showing a cross-section of a power system according to an embodiment of the present invention. Figure 2 This is a three-dimensional diagram of the aforementioned power system. Figure 3 This is a perspective view of the transmission unit between the engine and the hydraulic pump in the aforementioned power system, viewed from the hydraulic pump side. Figure 4 This is a three-dimensional view of the aforementioned transmission unit viewed from the engine side. Figure 5 This is a cross-sectional view of the aforementioned transmission unit. Figure 6 This is a perspective view of the part of the engine that connects to the transmission unit. Figure 7 This is a perspective view of the part of the transmission unit that connects to the hydraulic pump. Figure 8 It is equivalent to Figure 5 The sectional view is an explanatory diagram showing the connection structure between the transmission unit, the engine, and the hydraulic pump. Detailed Implementation

[0020] The first embodiment of the present invention will now be described with reference to the accompanying drawings.

[0021] (Powertrain) like Figure 1 , Figure 2 As shown, the power system 1 of this embodiment includes: an engine 10 (drive source), a hydraulic pump 15 (driven device), and a clutch unit 20 (transmission unit). Engine 10 is, for example, an inline four-cylinder internal combustion engine. Engine 10 houses crankshaft 12 (drive shaft) within crankcase 11. Engine 10 causes output shaft 13, for example, coaxial with crankshaft 12, to protrude outside crankcase 11. Output shaft 13 outputs rotational driving force as engine 10 operates.

[0022] A hydraulic pump 15 is connected to the output shaft 13 via a hydraulic clutch 24 (transmission device) provided in the clutch unit 20. The hydraulic pump 15 is driven by receiving rotational power from at least one of the engine 10 and the electric generator 18 (described later). The hydraulic pump 15 generates hydraulic pressure for external supply by means of the drive. The hydraulic pressure generated by the hydraulic pump 15 is supplied to hydraulic actuators of, for example, construction machinery and industrial machinery.

[0023] The hydraulic clutch 24 is engaged by supplying hydraulic pressure, enabling the transmission of rotational driving force between the output shaft 13 of the engine 10 and the input section 16 (input shaft) of the hydraulic pump 15. Hereinafter, the output shaft 13 will be referred to as the engine output shaft 13, the input section 16 as the input shaft 16, and the hydraulic clutch 24 as the clutch 24. In the diagram, line C1 represents the rotation center axis of the coaxial output shaft 13 and input section 16. The axial direction of the output shaft 13 (along axis C1, in the direction of arrow F11 in the diagram) is taken as the horizontal direction for the vehicle-mounted power system 1. Arrow F12 in the diagram represents the width direction, which is orthogonal to the axial direction F11 and becomes horizontal when mounted in a vehicle. Arrow F13 in the diagram represents the up-down direction, which is orthogonal to both the axial direction F11 and the width direction and becomes vertical when mounted in a vehicle.

[0024] Power system 1 is installed in special vehicles such as engineering machinery like hydraulic excavators and industrial machinery like forklifts. These vehicles are equipped with hydraulic actuators such as hydraulic cylinders and hydraulic motors. Power system 1 generates hydraulic pressure to supply the hydraulic actuators of the vehicles.

[0025] Clutch unit 20 is disposed between the output shaft 13 of engine 10 and the input section 16 of hydraulic pump 15. Clutch unit 20 is smaller in size than engine 10 and is easily replaceable with different engines 10. The input section 16 of hydraulic pump 15 is a rotating element coaxially disposed with the output shaft 13 of engine 10. Clutch unit 20 includes a clutch 24 that disconnects the power transmission between the output shaft 13 of engine 10 and the input section 16 of hydraulic pump 15. Clutch 24 switches whether power transmission between the output shaft 13 of engine 10 and the input section 16 of hydraulic pump 15 is permitted.

[0026] The clutch unit 20 includes a transmission housing 30 that houses the clutch 24 and the like. The transmission housing 30 is disposed between the engine 10 and the hydraulic pump 15 on the axial direction F11 of the output shaft 13. Refer to together Figures 3-5 The transmission housing 30 includes: a cylindrical housing portion 31, which is cylindrical and houses the output shaft 13 of the engine 10 and a rotating element coaxial therewith; a wheel cover 32, which has a larger diameter than the cylindrical housing portion 31 and is disposed on the engine 10 side of the cylindrical housing portion 31, and houses the flywheel 13a disposed on the output shaft 13; and a flat housing portion 33, which is disposed on the hydraulic pump 15 side of the cylindrical housing portion 31 and is flat in shape, with the width of the axial direction F11 being narrower than the widths of the width direction F12 and the vertical direction F13.

[0027] Viewed axially from F11, the flat housing portion 33 extends vertically and outwards towards one side in the width direction. Viewed axially from F11, the flat housing portion 33 is approximately triangular in shape. The portion of the flat housing portion 33 on the width direction side protrudes further into the width direction than the wheel cover 32 when viewed axially. This protruding portion is referred to as the protrusion 34. Furthermore, the side of the flat housing portion 33 facing the engine 10 in the axial direction is referred to as the first side surface 35, and the side of the flat housing portion 33 facing the hydraulic pump 15 in the axial direction is referred to as the second side surface 36. For example, the first side surface 35 and the second side surface 36 are planar shapes orthogonal to the axial direction.

[0028] Along the axial direction F11, at least a portion (in this embodiment, it is integral) of the wheel cover 32 is disposed on the engine 10 side of the flat housing portion 33 (closer to the engine 10 side than the first side 35). Along the axial direction F11, at least a portion (in this embodiment, it is integral) of the electric generator (second drive source) 18 is disposed on the engine 10 side of the protrusion 34 of the flat housing portion 33 (closer to the engine 10 side than the first side 35). Along the axial direction F11, on the engine 10 side of the flat housing portion 33 (closer to the engine 10 side than the first side 35), the hydraulic regulator 60 of the oil supply control device 50 (described later) and the oil circuit switching valve 70 are also disposed.

[0029] The electric generator 18 is configured as, for example, an MR electric motor. The electric generator 18 is connected to the vehicle's power supply (secondary battery) via an inverter (not shown). The electric generator 18 functions as an electric motor that generates a second driving force independently of the engine 10, corresponding to the power supply from the vehicle's power source. The electric generator 18 also functions as a generator that produces electricity in response to the power transmission from the engine 10. For example, the electricity generated by the electric generator 18 charges the vehicle's power source. The power transmitted between the electric generator 18 and the vehicle's power source is regulated by an inverter (not shown).

[0030] The power system 1 includes a control unit 17, which is an electronic control unit (ECU). The control unit 17 includes: an arithmetic processing circuit that performs various arithmetic processing related to the driving of the engine 10; and a storage device that stores control programs and data.

[0031] Various detection signals are input to the control unit 17. These detection signals include: engine speed (e.g., crankshaft speed), various temperatures of the engine 10, throttle input (output requirement), vehicle speed and other vehicle status, and the amount of power stored in the on-board power supply. Based on these detection signals, the control unit 17 performs operation control of the power system 1. This operation control includes: engine 10 operation control, power operation and regeneration (power generation) control of the electric generator 18, and solenoid valve control of the fuel supply control device 50.

[0032] The electric generator 18 is connected to the engine 10 in a driveable manner via a clutch 24. The electric generator 18 can transmit power to the engine 10 when the clutch is engaged, and cannot transmit power to the engine 10 when the clutch is disengaged. The electric generator 18 is always connected to the hydraulic pump 15 in a driveable manner without using the clutch 24.

[0033] The power system 1 switches between transmitting power between the engine 10 and the hydraulic pump 15, and between the engine 10 and the electric generator 18, by disengaging the clutch 24. When the clutch 24 is engaged, power can be transmitted between the engine 10 and the hydraulic pump 15, and between the engine 10 and the electric generator 18. When the clutch 24 is disengaged, power cannot be transmitted between the engine 10 and the hydraulic pump 15, or between the engine 10 and the electric generator 18.

[0034] The power system 1 can operate in the following first, second, and third operating modes by controlling the disengagement of the clutch 24. The clutch unit 20 switches the power transmission path so that power to drive the hydraulic pump 15 is transmitted from at least one of the engine 10 and the electric generator 18.

[0035] In the first operating mode (engine-driven mode (charging mode)), clutch 24 is engaged, and the hydraulic pump 15 is driven by the engine 10, which in turn drives the electric generator 18. That is, the engine 10 can simultaneously drive the electric generator 18 to generate electricity and the hydraulic pump 15 to generate hydraulic pressure. Thus, the vehicle's power supply can be charged while the output of the hydraulic pump 15 is used for vehicle operation. Furthermore, if the structure allows the vehicle's kinetic energy to be input from the output shaft 13 to the electric generator 18, then the first operating mode is also a regeneration mode that regenerates the vehicle's kinetic energy into electricity.

[0036] In the second operating mode (engine + electric motor drive mode (engine-assisted mode)), clutch 24 is engaged, and the hydraulic pump 15 is driven by both the engine 10 and the electric generator 18. That is, the hydraulic pump 15 can be driven to generate hydraulic pressure using the power of both the engine 10 and the electric motor. Thus, the electric generator 18 can assist the engine 10 in driving the hydraulic pump 15, and high output can be obtained.

[0037] In the third operating mode (electric motor drive mode), clutch 24 is disengaged, the engine 10 is stopped, and only the electric generator 18 is driven. The electric generator 18 drives the hydraulic pump 15. That is, the engine 10 can be stopped, and hydraulic pressure can be generated by driving the hydraulic pump 15 solely through the electric generator 18. Thus, hydraulic pressure can be obtained by driving the hydraulic pump 15 using the electric generator 18 while the engine 10 is stopped.

[0038] (Clutch unit) like Figures 1-5 As shown, the clutch unit 20 includes: a clutch 24 that operates by supplying hydraulic pressure; and an oil supply control device 50 that controls the supply of working oil to the clutch 24. Reference Figure 5The clutch unit 20 includes: a first connecting shaft 21 rotatably connected to the output shaft 13 of the engine 10; and a second connecting shaft 22 rotatably connected to the input section 16 of the hydraulic pump 15. The first connecting shaft 21 is coaxially configured with the output shaft 13 of the engine 10 and rotates integrally with the output shaft 13. The second connecting shaft 22 is coaxially configured with the input section 16 of the hydraulic pump 15 and rotates integrally with the input shaft. The first connecting shaft 21 and the second connecting shaft 22 are coaxially configured with each other, and a clutch 24 is provided between these first connecting shafts 21 and the second connecting shaft 22. The first connecting shaft 21 and the second connecting shaft 22 are connected via the clutch 24 in a manner that allows for the disconnection of power transmission.

[0039] Clutch 24 operates by receiving hydraulic pressure from an external source (oil pump 14). Clutch 24 is a normally open hydraulic clutch. Clutch 24 is engaged (capable of power transmission between engine 10 and hydraulic pump 15) due to the external hydraulic supply. Clutch 24 is disengaged (unable to transmit power between engine 10 and hydraulic pump 15) when the external hydraulic supply ceases. For example, clutch 24 is a multi-plate clutch with multiple circular friction plates (clutch plates) coaxial with output shaft 13.

[0040] The oil supply control device 50 controls (regulates) the oil (hydraulic pressure) discharged by the oil pump 14, which is linked to the engine 10, to a constant pressure for output. When the clutch is engaged, the oil supply control device 50 supplies the regulated, constant hydraulic pressure to the clutch 24. The oil pump 14 is integrated with the engine 10. The oil pump 14 is driven along with the engine 10. The oil pump 14 is always driven in conjunction with the crankshaft 12 after the engine starts. The engine speed of 10 increases as output demand increases. The oil pump 14 increases its discharge volume as the engine speed increases. The flow rate of oil returning from the oil supply control device 50 to the upstream side of the oil pump 14 increases as the engine speed increases.

[0041] When hydraulic pressure is supplied to clutch 24 from oil supply control device 50, clutch 24 is engaged, and first connecting shaft 21 and second connecting shaft 22 are connected in a power-transmitting manner. When the hydraulic pressure supply to clutch 24 is removed, clutch 24 is disengaged, releasing the power-transmitting connection between first connecting shaft 21 and second connecting shaft 22 (i.e., power cannot be transmitted).

[0042] Refer to together Figure 3 , Figure 4Viewed from the axial direction F11, the flat housing portion 33 of the transmission housing 30 extends vertically and outwards towards the width direction. Viewed from the axial direction F11, the flat housing portion 33 is approximately triangular in shape. The shape of the flat housing portion 33 as viewed along the axial direction F11 will be described below. The flat housing portion 33 has the following: a first circular portion 37 centered on the output shaft 13; and a second circular portion 38 and a third circular portion 39 arranged vertically at a position separated from the first circular portion 37 in the width direction. The outer periphery of the flat housing portion 33 has the following: an upper side portion 41 along a tangent connecting the first circular portion 37 and the second circular portion 38 from above; a lower side portion 42 along a tangent connecting the first circular portion 37 and the third circular portion 39 from below; and a side portion 43 along a tangent connecting the second circular portion 38 and the third circular portion 39 from the width direction.

[0043] Reference Figure 5 A cylindrical housing portion 31, which protrudes towards the engine 10 side from the first side surface 35, is provided on the engine 10 side, opposite to the width direction of the flat housing portion 33. Clutch fluid, i.e., clutch operating oil, is stored inside the transmission housing 30. The transmission housing 30 also serves as an oil tank 30a for storing clutch fluid.

[0044] The electric generator 18 has an output shaft (second output shaft, hereinafter sometimes referred to as the motor output shaft) 19 parallel to the output shaft 13 of the engine 10. The electric generator 18 generates a second driving force independently of the engine 10. The motor output shaft 19 of the electric generator 18 is offset radially relative to the output shaft 13 of the engine 10. For example, in the illustrated example, the motor output shaft 19 is offset radially upward relative to the output shaft 13. Viewed axially from each output shaft 13, 19, the motor output shaft 19 and the electric generator 18 are positioned to avoid the connecting element 23 and the connecting housing portion 48 described later.

[0045] A transmission gear train (transmission mechanism) 44 is configured between the electric generator 18 and the hydraulic pump 15. The transmission gear train 44 transmits power between the output shaft 13 of the engine 10 and the output shaft 19 of the electric motor. The transmission gear train 44 increases the rotational speed of the output shaft 13 of the engine 10 and transmits it to the output shaft 19 of the electric motor. The transmission gear train 44 can also decrease the rotational speed of the output shaft 19 of the electric motor and transmit it to the output shaft 13 of the engine 10. The transmission gear train 44 includes: a first gear shaft 45 coaxial with the output shaft 19 of the electric motor; a second gear shaft 46 coaxial with the input section 16 of the hydraulic pump 15; and a relay gear shaft 47 disposed between the first gear shaft 45 and the second gear shaft 46.

[0046] A first transmission gear 45a is integrally mounted on a first gear shaft 45. A second transmission gear 46a is integrally mounted on a second gear shaft 46. A first relay gear 47a, meshing with the first transmission gear 45a, and a second relay gear 47b, meshing with the second transmission gear 46a, are integrally mounted on a relay gear shaft 47 in a rotatable manner. The first transmission gear 45a has a smaller diameter than the first relay gear 47a. The second relay gear 47b has a smaller diameter than the second transmission gear 46a.

[0047] Therefore, the driving force of the electric generator 18 is decelerated between the first transmission gear 45a and the first relay gear 47a, and also decelerated between the second relay gear 47b and the second transmission gear 46a, and transmitted to the hydraulic pump 15. When the clutch is engaged, the driving force of the engine 10 is accelerated between the second transmission gear 46a and the second relay gear 47b, and also accelerated between the first relay gear 47a and the first transmission gear 45a, and transmitted to the electric generator 18.

[0048] The connecting element 23 is a rotating element that can connect the output shaft 13 of the engine 10 and the input section 16 of the hydraulic pump 15 in an integral rotatable manner. The connecting element 23 includes: first and second connecting shafts 21 and 22, and a clutch 24 that disconnects the power transmission between these connecting shafts 21 and 22. The connecting element 23 is housed in the connecting housing portion 48. Unlike the connecting element 23, the output shaft 13, and the input portion 16, the connecting housing portion 48 is a non-rotating element that does not rotate relative to the main body (body) of the engine 10 and the hydraulic pump 15. The connecting housing portion 48 includes: a first circular portion 37 of the transmission housing, a cylindrical housing portion 31, and a wheel cover 32.

[0049] As described above, the clutch unit 20 having the above component configuration includes: a connecting element 23 that is transmissively connected to the output shaft 13 of the engine 10 and the input shaft 16 of the hydraulic pump 15 driven by the driving force of the engine 10; and an electric generator 18 that generates driving force independently of the engine 10, wherein the electric generator 18 is disposed away from the connecting element 23 when viewed from the axial direction of the output shaft 13. The power system 1 of this embodiment includes: the clutch unit 20, the engine 10, and the hydraulic pump 15.

[0050] According to this structure, by offsetting the electric generator 18 relative to the connecting element 23 of the engine 10 and the hydraulic pump 15, the increase in the axial width of the transmission unit and the power system having the transmission unit can be suppressed compared to the case where the electric generator 18 is coaxially arranged with the engine 10. In addition, compared to the case where the electric generator 18 is clamped between the output shaft 13 of the engine 10 and the input shaft 16 of the hydraulic pump 15, the electric generator 18 is more easily accessible from the outside, which improves maintainability.

[0051] In the aforementioned clutch unit 20, the electric generator 18 has a motor output shaft 19 offset relative to the output shaft 13, and a transmission mechanism 44 is provided between the output shaft 13 and the motor output shaft 19, which can increase the driving force of the output shaft 13 and transmit it to the motor output shaft 19. According to this structure, the driving force of the engine 10 can be increased and transmitted to the electric generator 18, thereby increasing the power generation of the electric generator 18. In addition, by slowing down the driving force of the electric generator 18 and transmitting it to the engine 10 and the hydraulic pump 15, the output of the electric generator 18 can be suppressed. Therefore, it is possible to achieve a small size and lightweight design for the electric generator 18.

[0052] In the clutch unit 20 described above, a transmission mechanism 44 capable of transmitting power is provided between the output shaft 13 and the motor output shaft 19, and a transmission housing 30 for housing the transmission mechanism 44 is provided. A wheel cover 32 for housing a flywheel 13a that rotates integrally with the output shaft 13 is provided on the motor side of the transmission housing 30. The electric generator 18 is disposed on the motor side of the transmission housing 30 away from the wheel cover 32. According to this structure, the wheel cover 32 and the electric generator 18 can be efficiently configured on the engine 10 side of the transmission housing 30, and the clutch unit 20 can be miniaturized.

[0053] In the clutch unit 20 described above, the transmission housing 30 has a flat housing portion 33, which is formed such that the width of the axial direction F11 is narrower than the width of the orthogonal direction (width direction F12 and vertical direction F13) orthogonal to the axial direction F11, and is disposed on the axial direction F11 between the engine 10 and the hydraulic pump 15. According to this structure, the transmission housing 30 has a flat housing portion 33 that is flat and disposed between the engine 10 and the hydraulic pump 15, which suppresses the width of the axial F11. Therefore, the capacity of the oil tank 30a can be ensured as much as possible, and the clutch unit 20 can be disposed without causing the engine 10 to be significantly separated from the driven part.

[0054] In the clutch unit 20 described above, the wheel cover 32 and the electric generator 18 are disposed on the engine 10 side of the flat housing portion 33. According to this structure, the wheel cover 32 and the electric generator 18 are concentrated in the part of the flat housing 33 on the engine 10 side. Therefore, compared with the case where the wheel cover 32 and the electric generator 18 are respectively arranged on both sides of the axial direction of the flat housing 33, the clutch unit 20 can be made more compact.

[0055] In the clutch unit 20 described above, the connecting element 23 includes a clutch 24 that disconnects the power transmission between the engine 10 and the hydraulic pump 15. The electric generator 18 is connected to the engine 10 in a driveable manner via the clutch 24, and the electric generator 18 is connected to the hydraulic pump 15 in a driveable manner without via the clutch 24. According to this structure, if the clutch 24 is engaged, the engine 10 can be used to drive the hydraulic pump 15 and the electric generator 18 can be used to generate electricity. At this time, if the electric generator 18 is put into operation, the electric generator 18 can be used to assist the drive of the engine 10. Furthermore, if the clutch 24 is disengaged and the electric generator 18 is powered to operate, the hydraulic pump 15 can be driven solely by the electric generator 18 while the engine 10 is stopped.

[0056] The following is for reference Figures 6-8 The connection structure of the engine 10, clutch unit 20, and hydraulic pump 15 according to the second embodiment of the present invention will be described. For ease of illustration, Figures 1-5 Structure and Figures 6-8 The structure has different parts.

[0057] A flywheel 13a is provided at the outer axial end of the output shaft 13 of the engine 10. A first connecting part 11a is provided at the outer axial part of the flywheel 13a. The first connecting part 11a is a connecting part for connecting a mating part (e.g., input shaft 16) that transmits driving force from the output shaft 13 to the output shaft 13.

[0058] A second connecting part 15a is provided on the axial outer side of the input part 16 of the hydraulic pump 15, which can be connected to the first connecting part 11a. The second connecting part 15a is a connecting part for connecting a mating part (e.g., output shaft 13) that transmits driving force to the input shaft 16 to the input shaft 16.

[0059] The output shaft 13 of the engine 10 and the input shaft 16 of the hydraulic pump 15 can be directly connected using the first and second connecting parts 11a and 15a. The first and second connecting parts 11a and 15a are connected in a detachable manner using multiple fasteners such as bolts and nuts. Through the connection of the first and second connecting parts 11a and 15a, power can be transmitted between the output and input shafts 13 and 16.

[0060] In this embodiment, a connecting element 23 of the clutch unit 20 is sandwiched between the first and second connecting portions 11a and 15a. The first and second connecting portions 11a and 15a are indirectly connected via the connecting element 23. Using this connection, rotational power can be transmitted between the input and output shafts 13 and 16 via the connecting element 23.

[0061] A drive-side connecting portion 23a is provided on one axial end of the connecting element 23 (the outer end of the first connecting shaft 21 on the engine 10 side) for connection to the first connecting portion 11a of the flywheel 13a. For example, the drive-side connecting portion 23a has the same shape as the second connecting portion 15a of the input shaft 16. The first connecting portion 11a and the drive-side connecting portion 23a are connected in a detachable manner using multiple fasteners such as bolts and nuts. Figure 8 As shown, the first connecting shaft 21 can be composed of multiple components that are splined together.

[0062] At the other axial end of the connecting element 23 (the outer end of the second connecting shaft 22 on the side of the hydraulic pump 15), a driven-side connecting portion 23b is provided, which can be connected to the second connecting portion 15a of the input shaft 16. For example, the driven-side connecting portion 23b has the same shape as the first connecting portion 11a of the flywheel 13a. The second connecting portion 15a and the driven-side connecting portion 23b are connected in a detachable manner using multiple fasteners such as bolts and nuts. Figure 8 As shown, the second connecting shaft 22 can be composed of multiple components that are splined together. Figure 7 As shown, a wheel portion 23c, identical to that of the flywheel 13a, may also be provided around the driven side connecting portion 23b.

[0063] Each connecting portion 23a, 23b of the connecting element 23 sandwiched between the first and second connecting portions 11a, 15a has the following structure: the driving-side connecting portion 23a of the connecting element 23 connected to the first connecting portion 11a has the same shape as the second connecting portion 15a, and the driven-side connecting portion 23b of the connecting element 23 connected to the second connecting portion 15a has the same shape as the first connecting portion 11a.

[0064] This simplifies the design of the connection structure between the connecting element 23 and the input / output shafts 13 and 16, and also simplifies the connection operation between the connecting element 23 and the input / output shafts 13 and 16. Furthermore, the connecting portions 23a and 23b are not limited to the aforementioned identical shapes. Each connecting portion 23a and 23b can be any structure that connects to the first and second connecting portions 11a and 15a in a transmissible manner.

[0065] A drive-side housing connection portion 48a is provided at one axial end of the connection housing portion 48 that houses the connection element 23 (the outer periphery of the open end on the engine 10 side of the wheel cover 32). The drive-side housing connection 48a is formed as a flange extending along the outer periphery of the open end of the wheel cover 32.

[0066] A first body connection portion 11c is provided around the first connection portion 11a of the output shaft 13 on the outer side of the engine body (e.g., crankcase 11). The first body connection portion 11c is located on the outer periphery of the closure plate 11b that intersects the axial direction. The first body connection portion 11c is connected to the drive-side housing connection portion 48a in a detachable manner using multiple fasteners such as bolts and nuts.

[0067] A cover 15b, identical to the wheel cover 32, is provided around the second connecting portion 15a of the input portion 16 on the body (pump body) of the hydraulic pump 15. When the hydraulic pump 15 is directly connected to the engine 10, the cover 15b internally houses the flywheel 13a. A second body connecting portion 15c is provided on the outer periphery of the open end of the cover 15b on the engine 10 side. The second body connecting portion 15c is a flange extending along the outer periphery of the open end of the cover 15b. For example, the second body connecting portion 15c has the same shape as the drive-side housing connecting portion 48a of the connecting housing portion 48.

[0068] A driven-side housing connection portion 48c is provided at the other axial end of the connecting housing portion 48 (the end on the side of the hydraulic pump 15). A sealing plate 48b, identical to the sealing plate 11b of the engine 10, is provided at the other axial end of the connecting housing portion 48. The driven-side housing connection portion 48c is located on the outer periphery of the sealing plate 48b. The driven-side housing connection portion 48c is connected to the second body connection portion 15c in a detachable manner using multiple fasteners such as bolts and nuts. For example, the driven-side housing connection portion 48c has the same shape as the first body connection portion 11c of the engine 10.

[0069] The first body connection portion 11c of the engine 10 and the second body connection portion 15c of the hydraulic pump 15 can be directly connected. In this embodiment, a connecting housing portion 48 of the clutch unit 20 is sandwiched between the first and second body connection portions 11c and 15c. The first and second body connection portions 11c and 15c are indirectly connected via this connecting housing portion 48.

[0070] Each connecting portion 48a, 48c of the connecting housing portion 48 has the following structure. That is, in the connecting housing portion 48, the drive-side housing connecting portion 48a connected to the first body connecting portion 11c of the engine 10 has the same shape as the second body connecting portion 15c of the hydraulic pump 15, and the driven-side housing connecting portion 48c connected to the second body connecting portion 15c of the hydraulic pump 15 has the same shape as the first body connecting portion 11c of the engine 10.

[0071] This simplifies the design of the connection structure between the housing 48 and the body of the engine 10 and hydraulic pump 15, and also simplifies the connection operation between the housing 48 and the engine 10 and hydraulic pump 15. Furthermore, the connecting parts 48a and 48c are not limited to the aforementioned identical shapes. Each connecting part 48a and 48c can be integrally connected to the first and second body connecting parts 11c and 15c.

[0072] As described above, the clutch unit 20 having the above-described connection structure includes: a connection element 23 that is connected in a driveable manner to the output shaft 13 of the engine 10 and the input shaft 16 of the hydraulic pump 15 driven by the driving force of the engine 10; and an electric generator 18 that generates driving force independently of the engine 10. The connection element 23 includes: a drive-side connection portion 23a that is connected to a first connection portion 11a provided on the output shaft 13; and a driven-side connection portion 23b that is connected to a second connection portion 15a provided on the input shaft 16 and capable of being connected to the first connection portion 11a. The power system 1 of the embodiment includes: the clutch unit 20, the engine 10, and the hydraulic pump 15.

[0073] According to this structure, when a clutch unit 20 with an electric generator 18 is installed between the engine 10 and the hydraulic pump 15, the clutch unit 20 can be installed without changing the interconnecting parts of the engine 10 and the hydraulic pump 15, and without installing other components. Therefore, by utilizing the interconnecting parts of the engine 10 and the hydraulic pump 15, the clutch unit 20 can be installed, enabling efficient hybridization of existing power systems.

[0074] In the clutch unit 20 described above, the driven side connecting part 23b has the same shape as the first connecting part 11a. According to this structure, the driven-side connection portion 23b of the clutch unit 20 has the same shape as the first connection portion 11a of the engine 10. Therefore, the clutch unit 20 can be installed without changing the second connection portion 15a of the hydraulic pump 15 or by clamping other components. As a result, existing power systems can be efficiently hybridized.

[0075] The clutch unit 20 described above includes a connecting housing portion 48 for housing the connecting element 23. The connecting housing portion 48 includes: a drive-side housing connecting portion 48a, which is connected to a first body connecting portion 11c provided on the body of the engine 10; and a driven-side housing connecting portion 48c, which is connected to a second body connecting portion 15c, which is provided on the body of the hydraulic pump 15 and can be connected to the first body connecting portion 11c. According to this structure, the connecting housing 48 of the clutch unit 20 can be connected without changing the connecting parts 11c and 15c of the engine 10 and the hydraulic pump 15, and without clamping other components. As a result, the existing power system can be efficiently hybridized.

[0076] In the clutch unit 20 described above, the driven side housing connection portion 48c has the same shape as the first body connection portion 11c. According to this structure, the driven-side housing connection portion 48c of the clutch unit 20 has the same shape as the first body connection portion 11c of the engine 10. Therefore, the clutch unit 20 can be installed without changing the second body connection portion 15c of the hydraulic pump 15 or by clamping other components. As a result, the existing power system can be efficiently hybridized.

[0077] In the clutch unit 20 described above, the connecting element 23 includes a clutch 24 that disconnects the power transmission between the engine 10 and the hydraulic pump 15. The electric generator 18 is connected to the engine 10 in a driveable manner via the clutch 24, and is connected to the hydraulic pump 15 in a driveable manner without via the clutch 24. According to this structure, if the clutch 24 is engaged, the engine 10 can be used to drive the hydraulic pump 15 and the electric generator 18 can be used to generate electricity. At this time, if the electric generator 18 is put into operation, the electric generator 18 can be used to assist in driving the engine 10. In addition, if the clutch 24 is disengaged and the electric generator 18 is put into operation, the hydraulic pump 15 can be driven solely by the electric generator 18 when the engine 10 is stopped.

[0078] Furthermore, the present invention is not limited to the embodiments described above. For example, the drive source is not limited to engine 10 (internal combustion engine) and may also be an electric motor. The clutch 24 may be a normally open type that is not connected by supplying hydraulic pressure, or a normally closed type that is disconnected by supplying hydraulic pressure. The transmission device is not limited to the clutch 24 that disconnects power transmission, but may also be a clutch that controls the gear shifting operation of a transmission. In addition, the transmission device may also be a transmission that performs gear shifting operation by supplying hydraulic pressure. Furthermore, the structure described above is an example of the present invention. Without departing from the spirit of the present invention, various modifications can be made, such as replacing the constituent elements of the above embodiments with known constituent elements. Industrial applicability

[0079] According to the transmission unit of the present invention, by offsetting the second drive source relative to the connecting element of the drive source and the driven device, the increase in axial width of the transmission unit and the power system having the transmission unit can be suppressed compared to the case where the second drive source is coaxially arranged with the drive source. In addition, compared to the case where the second drive source is clamped between the output shaft of the drive source and the input shaft of the driven device, the second drive source is easier to access from the outside, which improves maintainability. Explanation of reference numerals in the attached figures

[0080] 1-Power system; 10-Engine (drive source); 13-Output shaft; 13a-Flywheel (rotating body); 15-Hydraulic pump (driven device); 16-Input section (input shaft); 18-Electric generator (second drive source); 19-Electric motor output shaft (second output shaft); 23-Connecting element; 24-Clutch; 30-Transmission housing; 32-Wheel cover (rotating body cover); 33-Flat housing section; 44-Transmission mechanism; F11-Axial direction; F12-Width direction (orthogonal direction); F13-Up and down direction (orthogonal direction).

Claims

1. A transmission unit comprising: A connecting element that connects the output shaft of a drive source and the input shaft of a driven device driven by the driving force of the drive source in a transmissive manner; and The second driving source generates driving force independently of the aforementioned driving source. Viewed axially from the output shaft, the second drive source is configured to bypass the connecting element. The second drive source has a second output shaft offset relative to the output shaft. A transmission mechanism capable of transmitting power is provided between the output shaft and the second output shaft, and a transmission housing is provided to house the transmission mechanism. The transmission housing has a rotating body cover on the drive source side along the axial direction, the rotating body cover housing a rotating body that rotates integrally with the output shaft. The second drive source is located on the drive source side of the axial direction in the transmission housing, and is positioned obliquely above the output shaft in the radial direction, avoiding the rotating body cover.

2. The transmission unit according to claim 1, characterized in that, The transmission housing includes: A cylindrical housing portion, which is cylindrical in shape, houses the output shaft and the coaxial connecting element therewith; and A flat housing portion, disposed on the driven device side of the cylindrical housing portion, is formed into a flat shape with a narrow axial width.

3. The transmission unit according to claim 2, characterized in that, The connecting element includes a hydraulic clutch that disconnects the power transmission between the drive source and the driven device. An oil supply control device is provided on the drive source side of the flat housing portion, and the oil supply control device controls the supply of working oil to the hydraulic clutch.

4. The transmission unit according to claim 3, characterized in that, The second drive source is an electric generator, which is connected to the drive source in a transmissive manner via the hydraulic clutch. The second drive source is not connected to the driven device in a reversible manner via the hydraulic clutch.

5. A power system comprising: The transmission unit, the drive source, and the driven device as described in any one of claims 1 to 4.

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