Power transmission unit and power system

Abstract

A power transmission unit and a power system according to one embodiment of the present invention are provided with: an input shaft connected to a drive shaft of an internal combustion engine; an output shaft connected to a driven device so as to be capable of transmitting power; a transmission mechanism connecting the input shaft and the output shaft; and a motor generator having a rotating shaft connected to the input shaft and the output shaft via a transmission mechanism. When viewed from the axial direction of the input shaft, the motor generator is disposed on the outside in the radial direction intersecting the axial direction with respect to the input shaft.

Description

Technical Field

[0001] The invention relates to a power transmission unit and a power system.

[0002] This application claims priority based on Japanese Patent Application No. 2022-166663 filed in Japan on October 18, 2022, and the contents are incorporated herein. Background Art

[0003] As a power system mounted on a hybrid vehicle, there is known a structure including an engine, a motor generator, and a hydraulic pump operated by a driving force (rotational force) of at least one of the engine and the motor generator.

[0004] In a power system described in, for example, Patent Document 1 below, a one-way clutch is provided between the engine and the electric generator and the hydraulic pump. According to this power system, when the input shaft of the drive shaft connected to the engine rotates in one direction, the driving force of the input shaft is transmitted to the hydraulic pump via the one-way clutch. The driving force from the hydraulic pump to the engine that causes the input shaft to rotate in another direction is cut off by the one-way clutch. In a power system described in, for example, Patent Document 2 below, the drive shaft of the engine and the rotating shaft of the electric generator are arranged coaxially with the one-way clutch interposed therebetween.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-133455

[0008] Patent Document 2: Japanese Patent Application Publication No. 2002-103999 Summary of the invention

[0009] 1. Technical issues to be resolved

[0010] However, in the configuration described in Patent Document 2, for example, the drive shaft of the engine and the rotating shaft of the motor generator are coaxially arranged, which leads to an increase in the size of the power system in the axial direction.

[0011] The present invention provides a power transmission unit and a power system capable of suppressing an increase in the size of an output shaft in the axial direction.

[0012] (II) Technical solution

[0013] In order to solve the above-mentioned problems, the present invention adopts the following means.

[0014] (1) A power transmission unit of one embodiment of the present invention comprises: an input shaft connected to a drive shaft of an internal combustion engine; an output shaft connected to a driven device so as to transmit power; a transmission mechanism connecting the input shaft and the output shaft; and an electric generator having a rotating shaft connected to the input shaft and the output shaft via the transmission mechanism, the transmission mechanism comprising: a relay mechanism connecting the rotating shaft and the output shaft; and a one-way clutch that transmits a driving force of the input shaft in one direction to the rotating shaft and the output shaft via the relay mechanism, and at the same time cuts off a driving force that rotates the input shaft in another direction based on the rotating shaft and the output shaft between the relay mechanism and the input shaft, wherein the electric generator is arranged on the outer side of a radial direction intersecting the axial direction relative to the input shaft when viewed from the axial direction of the input shaft.

[0015] According to this scheme, compared with a structure in which the electric generator and the internal combustion engine are arranged axially, the axial enlargement of the power system caused by the addition of the electric generator can be suppressed. As a result, in the existing engine compartment, a hybrid power system can be installed without making the space for the power system with only the engine enlarged in the axial direction. In this case, a hybrid power system can also be provided by installing the electric generator after the existing power system.

[0016] Moreover, in the present embodiment, the input shaft is connected to the output shaft and the rotating shaft by a one-way clutch, which transmits the driving force of the input shaft in one direction to the rotating shaft and the output shaft via a relay mechanism, and at the same time cuts off the driving force that rotates the input shaft in another direction based on the rotating shaft and the output shaft between the relay mechanism and the input shaft.

[0017] According to this structure, the disconnection / connection state between the input shaft, the output shaft and the rotating shaft is switched by the rotation state of the input shaft, the output shaft and the rotating shaft. Therefore, unlike other clutches, power is not required when switching the disconnection / connection state. Thus, energy loss can be suppressed to a minimum.

[0018] (2) In the power transmission unit according to the above-mentioned aspect (1), it is preferable that the input shaft and the output shaft are arranged coaxially.

[0019] According to this aspect, it is easy to ensure a space for arranging the motor generator on the outside in the radial direction with respect to the input shaft and the output shaft.

[0020] (3) In the power transmission unit of the above-mentioned scheme (1) or (2), it is preferred that there is a mechanism accommodating portion for accommodating the transmission mechanism, and the one-way clutch comprises: an inner ring; an outer ring, which surrounds the inner ring and is connected to the output shaft; and an intermediate component, which connects the inner ring and the outer ring as the inner ring rotates in one direction, so that the inner ring and the outer ring rotate as a whole, and releases the connection between the inner ring and the outer ring as the outer ring rotates in the other direction, so that the outer ring and the inner ring rotate relative to each other, and the input shaft is rotatably supported on the mechanism accommodating portion in the middle part of the axial direction, and the input shaft is connected to the drive shaft outside the mechanism accommodating portion, and on the other hand, is connected to the inner ring inside the mechanism accommodating portion.

[0021] According to this aspect, compared with a structure in which both end portions of the input shaft are supported by bearings, the input shaft can be made more compact in the axial direction.

[0022] (4) In the power transmission unit according to the above aspect (3), preferably, the relay mechanism includes: a first gear fixed to the outer ring; and a second gear arranged between the first gear and the rotating shaft.

[0023] According to this aspect, it is possible to provide a relay mechanism that is excellent in reliability and durability of power transmission.

[0024] (5) In the power transmission unit of the above aspect (4), preferably, the first gear is fixed to a first side in the axial direction relative to the outer ring, and the output shaft is fixed to a second side in the axial direction relative to the outer ring.

[0025] According to this aspect, it is possible to transmit power between the outer ring and the motor generator and the driven device while suppressing the complication of the structure.

[0026] (6) In the power transmission unit according to any one of (1) to (5) above, it is preferred that a mechanism housing portion is provided to house the transmission mechanism, and the motor generator is arranged radially outward of the mechanism housing portion.

[0027] According to this aspect, it is possible to prevent the mechanism housing portion and the motor generator from overlapping each other when viewed from the axial direction. As a result, it is possible to reliably prevent the power transmission unit from increasing in size in the axial direction.

[0028] (7) The power system of the present embodiment comprises a power transmission unit according to any one of the above embodiments (1) to (6); an internal combustion engine having a driving shaft connected to the input shaft; and a driven device having a driven shaft connected to the output shaft.

[0029] According to this aspect, it is possible to provide a hybrid power system that is compact in the axial direction.

[0030] (III) Beneficial effects

[0031] According to the above-described aspects, it is possible to provide a power transmission unit and a power system in which an increase in the size of the output shaft in the axial direction can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a perspective view of a power system according to an embodiment.

[0033] Figure 2 It is a cross-sectional view of a power system according to an embodiment.

[0034] Figure 3 It is a rear view of the power system of the embodiment.

[0035] Figure 4 It is a front view of the one-way clutch according to the embodiment.

[0036] Figure 5 It is a cross-sectional view showing a connection portion between a motor case and a casing according to the embodiment.

[0037] Figure 6 This is a structural diagram for explaining a power system in which the one-way clutch is in a first connection operation mode.

[0038] Figure 7 This is a structural diagram for explaining a power system in which the one-way clutch is in the second connection operation mode.

[0039] Figure 8 This is a structural diagram for explaining the power system when the one-way clutch is in the third connection operation mode.

[0040] Fig. 9 This is a structural diagram for explaining a power system in which the one-way clutch is in a first disconnection operation mode.

[0041] Fig.10 This is a structural diagram for explaining a power system in which the one-way clutch is in the second disconnection operation mode. DETAILED DESCRIPTION

[0042] Next, embodiments of the present invention will be described based on the accompanying drawings. In the embodiments or modifications described below, corresponding structures are sometimes marked with the same symbols and the description is omitted. In the following description, expressions such as "parallel" or "orthogonal", "center", "coaxial", etc., which indicate relative or absolute configurations, include not only strict configurations, but also states where angles or distances are relatively displaced to the extent that there is a tolerance or the same function can be obtained. In this embodiment, "face to face" includes not only the situation where the orthogonal directions (normal directions) of the two faces are consistent with each other, but also the situation where the orthogonal directions intersect with each other.

[0043] [Power system 1]

[0044] Figure 1 It is a three-dimensional diagram of the power system 1. Figure 2 is a cross-sectional view of the power system 1 .

[0045] Figure 1 , Figure 2 The power system 1 shown is a hybrid power system mounted on a vehicle (for example, a special vehicle such as a hydraulic excavator, a construction machine such as an aerial work vehicle, a production machine such as a forklift, etc.). The power system 1 includes an engine (internal combustion engine) 2, a first transmission mechanism (transmission mechanism) 3, an electric generator 4, a second transmission mechanism 5, and a hydraulic pump 6. In the following description, the front, back, up, down, left, and right directions are the same as the directions of the vehicle. In this case, UP in the figure indicates the top, FR in the figure indicates the front, and LH in the figure indicates the left. The power transmission unit of this embodiment is composed of the first transmission mechanism 3, the electric generator 4, and the second transmission mechanism 5.

[0046] The first transmission mechanism 3 and the motor generator 4 are arranged in the vertical direction. The engine 2, the first transmission mechanism 3 and the hydraulic pump 6 are arranged in the front-rear direction. The power system 1 is mounted in the engine room of the vehicle with the engine 2 facing forward (and the hydraulic pump 6 facing backward).

[0047] <Engine 2>

[0048] The engine 2 functions as a first driving source. The engine 2 is, for example, an inline four-cylinder internal combustion engine. The engine 2 accommodates a crankshaft 12 in a crank housing 11 (see Figure 2 ).like Figure 2 As shown, the engine 2 makes a protruding shaft (drive shaft) 13 coaxial with, for example, the crankshaft 12 protrude outside the crank housing 11. The protruding shaft 13 rotates in one direction as the engine 2 runs. A flywheel 14 is connected to the protruding shaft 13. The flywheel 14 is formed in a disc shape coaxially arranged with the protruding shaft 13.

[0049] <First transmission mechanism 3>

[0050] like Figure 2 As shown, the first transmission mechanism 3 transmits the driving force from at least one of the driving sources of the engine 2 and the motor generator 4 to the hydraulic pump 6 , or transmits the driving force of the hydraulic pump 6 to the motor generator 4 .

[0051] The first transmission mechanism 3 includes a housing 21, an input shaft 22, a one-way clutch 23, a transmission shaft 24, a relay mechanism 25, and an output shaft 26. In the following description, the direction along the first axis O1 of the input shaft 22 is sometimes referred to as an axial direction, the direction intersecting the first axis O1 when viewed from the axial direction is sometimes referred to as a radial direction, and the direction around the first axis O1 is sometimes referred to as a circumferential direction. In this embodiment, the axial direction coincides with the front-rear direction.

[0052] Figure 3 It is a rear view of the power system 1.

[0053] like Figure 2 , Figure 3 As shown, the housing 21 includes a wheel receiving portion 31 (see Figure 2 ), the mechanism accommodating portion 32, the first supporting piece 33 and the second supporting piece 34.

[0054] The wheel housing portion 31 constitutes the front portion (the first side in the axial direction) of the housing 21 . The wheel housing portion 31 is formed in a bottomed cylindrical shape that is open toward the front. The flywheel 14 is housed in the wheel housing portion 31 .

[0055] The mechanism accommodating portion 32 is integrally formed with the wheel accommodating portion 31 at the rear (the second side in the axial direction) of the wheel accommodating portion 31. The mechanism accommodating portion 32 is larger than the wheel accommodating portion 31 when viewed from the front-rear direction. Specifically, the mechanism accommodating portion 32 includes a clutch accommodating portion 35 and an extension accommodating portion 36. An integral space is formed in the clutch accommodating portion 35 and the extension accommodating portion 36.

[0056] like Figure 2 As shown, the clutch housing portion 35 is a portion that overlaps with the wheel housing portion 31 when viewed from the front-to-back direction. A first communication hole 41a is formed in the partition wall 41 that separates the clutch housing portion 35 and the wheel housing portion 31 in the housing 21. The first communication hole 41a penetrates the portion of the partition wall 41 that is coaxial with the first axis O1 in the front-to-back direction. A second communication hole 42a is formed in the wall portion of the clutch housing portion 35 that faces the partition wall 41 in the front-to-back direction (hereinafter referred to as the opposing wall 42). The second communication hole 42a penetrates the portion of the opposing wall 42 that is coaxial with the first axis O1 in the front-to-back direction.

[0057] The extension housing portion 36 extends upward (outward in the radial direction) relative to the clutch housing portion 35 . Figure 3 In the example of FIG. 1 , the extended accommodation portion 36 extends obliquely upward to the left when viewed in the front-rear direction. Figure 2As shown, the extension accommodation portion 36 includes wall portions (a first wall portion 43 and a second wall portion 44) facing each other in the front-to-back direction. A bearing housing 43a is formed in the first wall portion 43. A bearing housing 44a is formed in the second wall portion 44. A through hole 44b is formed in a portion of the second wall portion 44 located on the inner side relative to the bearing housing 44a. The through hole 44b penetrates the second wall portion 44 in the front-to-back direction.

[0058] like Figure 3 As shown, the first support piece 33 protrudes upward from a portion of the clutch accommodation portion 35 that is located on the right side of the extension accommodation portion 36 .

[0059] The second support piece 34 protrudes upward from the extension housing portion 36. The front ends of the first support piece 33 and the second support piece 34 are located at the same height in the vertical direction.

[0060] like Figure 2 As shown, the input shaft 22 passes through the first connecting hole 41a in the front-to-back direction. Specifically, the input shaft 22 extends in the front-to-back direction coaxially with the first axis O1. The central portion of the input shaft 22 in the front-to-back direction is rotatably supported on the partition wall 41 via a bearing 46 provided in the first connecting hole 41a. The front end portion (the first side end portion in the axial direction) of the input shaft 22 protrudes into the wheel accommodating portion 31. A shock absorber 50 is provided at the front end portion of the input shaft 22. The shock absorber 50 is formed of an elastically deformable material (for example, rubber, etc.). The shock absorber 50 is a disc-shaped component. The flywheel 14 is fixed to the shock absorber 50 in a state of overlapping in the front-to-back direction. The rear end portion (the second side end portion in the axial direction) of the input shaft 22 protrudes into the clutch accommodating portion 35.

[0061] Figure 4 It is a front view of the one-way clutch 23 .

[0062] like Figure 2 , Figure 4 As shown, the one-way clutch 23 transmits the rotation of the input shaft 22 in one direction to the hydraulic pump 6. The one-way clutch 23 restricts the input shaft 22 from rotating in the other direction by the driving force of the hydraulic pump 6 or the motor generator 4. The one-way clutch 23 is, for example, a cam type. The one-way clutch 23 includes an inner ring 51, an outer ring 52, and a roller (intermediate member) 53.

[0063] The inner ring 51 is located at the rear end portion of the input shaft 22 .

[0064] The outer ring 52 is arranged so as to surround the inner ring 51 .

[0065] The roller 53 is configured to be movable between a connection state in which the inner ring 51 and the outer ring 52 are connected and a disconnection state in which the connection between the inner ring 51 and the outer ring 52 is released. A plurality of rollers 53 are provided at intervals in the circumferential direction. Each roller 53 is maintained to be movable individually in a plurality of cam grooves 52a provided in the outer ring 52, for example. The surface of the cam groove 52a facing the inner side in the radial direction (hereinafter referred to as the cam surface) becomes shorter in distance from the outer peripheral surface of the inner ring 51 as it faces one side D1 in the circumferential direction. The roller 53 is urged toward the other side D2 in the circumferential direction by the urging member 54.

[0066] In the one-way clutch 23, when the inner ring 51 rotates in one direction, the roller 53 moves in the cam groove 52a to one side D1 in the circumferential direction due to friction with the inner ring 51. As a result, the roller 53 is sandwiched between the inner ring 51 and the outer ring 52 (cam surface), so that the inner ring 51 and the outer ring 52 are connected via the roller 53 (connected state). In the connected state, the inner ring 51 and the outer ring 52 can rotate in one direction as a whole. In the one-way clutch 23, when the outer ring 52 rotates in one direction, the roller 53 moves in the cam groove 52a to the other side D2 in the circumferential direction. As a result, the roller 53 is in a state where there is a gap between the inner ring 51 and the outer ring 52 (cam surface). That is, the rotation of the outer ring 52 is not transmitted via the roller 53, and the outer ring 52 rotates relative to the inner ring 51 (disconnected state). The roller 53 can be held by the inner ring 51.

[0067] like Figure 2 As shown, the transmission shaft 24 is supported in the extension housing portion 36 so as to be rotatable about the second axis O2 parallel to the first axis O1. Specifically, the front end portion of the transmission shaft 24 is supported so as to be rotatable via a bearing 55 provided in the bearing housing 43a. The middle portion of the transmission shaft 24 in the front-to-back direction is supported so as to be rotatable via a bearing 56 provided in the bearing housing 44a. The rear end portion of the transmission shaft 24 protrudes to the outside of the extension housing portion 36 through the through hole 44b.

[0068] The relay mechanism 25 relays the driving force between the input shaft 22 and the transmission shaft 24. The relay mechanism 25 includes a first gear 61 and a second gear 62.

[0069] The first gear 61 is arranged coaxially with the first axis O1 in the clutch housing portion 35. The first gear 61 is fixed to the outer ring 52 of the one-way clutch 23. Specifically, the first gear 61 is fixed to the outer ring 52 in a state of overlapping with the outer ring 52 from the front. The first gear 61 can rotate integrally with the outer ring 52. The first gear 61 is rotatably supported by the partition wall 41 via a bearing 64 provided in the first communication hole 41a.

[0070] The second gear 62 is disposed coaxially with the second axis O2 in the extension housing portion 36. The second gear 62 is fixed to the transmission shaft 24. The second gear 62 meshes with the first gear 61.

[0071] The output shaft 26 is arranged behind the one-way clutch 23 in the clutch accommodating portion 35. Specifically, the output shaft 26 includes a flange portion 26a and a shaft portion 26b.

[0072] The flange 26a is fixed to the outer ring 52 in a state of overlapping with the outer ring 52 from behind. The first gear 61 and the flange 26a sandwich the outer ring 52 from both sides in the front-rear direction. The first gear 61 and the flange 26a are connected by screws 65. The screws 65 penetrate the outer ring 52 in the front-rear direction.

[0073] The shaft portion 26b protrudes forward from the flange portion 26a. The shaft portion 26b is formed in a hollow shape extending coaxially with the first axis O1. The rear end portion of the shaft portion 26b is rotatably supported by the facing wall 42 via a bearing 66 provided in the second communication hole 42a.

[0074] <Motor generator 4>

[0075] like Figure 1 , Figure 3 As shown, the motor generator 4 is connected to the vehicle-mounted power supply (secondary battery) via the inverter 67. The motor generator 4 functions as a second drive source (motor) that generates driving force based on the power supply from the vehicle-mounted power supply. The motor generator 4 functions as a generator that generates power based on the power transmission from the engine 2. For example, the power generated by the motor generator 4 is charged to the vehicle-mounted power supply. The power exchanged between the motor generator 4 and the vehicle-mounted power supply is adjusted by the inverter 67.

[0076] like Figure 3 As shown, the motor generator 4 is arranged at a position that does not overlap with the first axis O1 when viewed from the front-to-back direction. Specifically, the motor generator 4 is arranged at a portion that is above the clutch housing portion 35 and is located on the right side relative to the extension housing portion 36 in a state of protruding upward from the extension housing portion 36. That is, the motor generator 4 is arranged radially outside relative to the mechanism housing portion 32. In this case, at least a portion of the motor generator 4 overlaps with the engine 2 when viewed from the front-to-back direction. The motor generator 4 preferably overlaps with the engine 2 in its entirety.

[0077] like Figure 2 As shown in FIG. 1 , at least a portion of the motor generator 4 is disposed within the width of the housing 21 in the front-rear direction. Figure 1~Figure 3As shown, the motor generator 4 at least partially overlaps with the wheel housing portion 31 and the clutch housing portion 35 when viewed from the top and bottom. At least partially overlaps with the extension housing portion 36 when viewed from the left and right. The motor generator 4 is preferably entirely disposed within the width of the housing 21 in the front-to-back direction.

[0078] The motor generator 4 includes a motor case 71 and a motor main body (not shown) accommodated in the motor case 71 .

[0079] The motor housing 71 is formed in a cylindrical shape extending in the front-rear direction. Figure 3 As shown in FIG. 1 , the motor housing 71 is formed with a first mounting piece 71 a and a second mounting piece 71 b that extend downward.

[0080] Figure 5 It is a cross-sectional view showing a connection portion between the motor case 71 (first mounting piece 71 a ) and the housing 21 (support piece 33 ).

[0081] like Figure 3 , Figure 5 As shown in FIG. 1 , the first mounting piece 71a extends downward from the portion of the motor housing 71 located on the right side. The first mounting piece 71a is composed of a pair of opposing pieces facing each other in the front-to-back direction. The first mounting piece 71a is arranged so that the pair of opposing pieces sandwich the first support piece 33 from both sides in the front-to-back direction. The first mounting piece 71a and the first support piece 33 are fastened to each other in the axial direction by a fastening member 72 (e.g., a bolt and a nut).

[0082] The second mounting piece 71b extends downward from the portion of the motor housing 71 located on the left side. The second mounting piece 71b is composed of a pair of opposing pieces facing each other in the front-to-back direction, similarly to the first mounting piece 71a. The second mounting piece 71b is arranged so that the pair of opposing pieces sandwich the second support piece 34 from both sides in the front-to-back direction. The second mounting piece 71b and the second support piece 34 are fastened to each other in the front-to-back direction by a fastening member 73 (for example, a bolt and a nut).

[0083] The motor body is housed in the motor case 71 in a state where the axis line of the rotating shaft 75 (hereinafter referred to as the third axis line O3 ) is arranged parallel to the first axis line O1 . The rotating shaft 75 protrudes rearward from the motor case 71 .

[0084] <Second transmission mechanism 5>

[0085] like Figure 1 , Figure 3 As shown, the second transmission mechanism 5 transmits driving force between the motor generator 4 and the transmission shaft 24. The second transmission mechanism 5 includes a first drive pulley 81, a second drive pulley 82, a plurality of driven pulleys 83, a belt 84, and a tensioner 85.

[0086] The first driving pulley 81 is fixed to the rear end portion of the rotating shaft 75. The first driving pulley 81 rotates together with the rotating shaft 75 around the third axis line O3.

[0087] The second drive pulley 82 is fixed to the rear end portion of the transmission shaft 24. The second drive pulley 82 rotates together with the transmission shaft 24 around the second axis line O2.

[0088] The plurality of driven pulleys 83 are located on the left side of the motor generator 4 and are arranged side by side in the vertical direction above the second driving pulley 82. Each driven pulley 83 is supported by the housing 21 so as to be rotatable about an axis along the front-rear direction.

[0089] The belt 84 is hung between the pulleys 81 to 83. The belt 84 moves between the pulleys 81 to 83 as the driving pulleys 81 and 82 on one side rotate with the rotation of the rotating shaft 75 or the transmission shaft 24. Thus, the driving force of one of the rotating shaft 75 and the transmission shaft 24 is transmitted to the other shaft.

[0090] The tensioner 85 includes a pair of tension rollers 85a facing each other with the belt 84 interposed therebetween. The tension rollers 85a are configured to be movable in directions approaching or separating from each other around the third axis O3. The tensioner 85 adjusts the tension of the belt 84 as the tension rollers 85a move.

[0091] <Hydraulic pump 6>

[0092] like Figure 2 As shown, the hydraulic pump 6 generates hydraulic pressure based on the driving force input from at least one of the driving sources of the engine 2 and the motor generator 4. The hydraulic pump 6 is connected to a hydraulic actuator (driven device) mounted on the vehicle. The hydraulic pressure generated by the hydraulic pump 6 is supplied to various hydraulic actuators. The hydraulic pump 6 is installed at the rear of the housing 21. The rotating shaft (driven shaft) 6a of the hydraulic pump 6 passes through the second connecting hole 42a and is fixed to the output shaft 26. Thus, the hydraulic pump 6 is connected to the output shaft 26 so that power can be transmitted. In this embodiment, as the hydraulic actuator, a hydraulic cylinder or a hydraulic motor can be listed.

[0093] The power system 1 includes a control unit 90 as an electronic control unit (ECU). The control unit 90 includes: an operation processing circuit that performs various operation processing related to the driving of the engine 2, etc.; and a storage device that stores programs or data for control. Various detection signals are input to the control unit 90. The detection signals include the rotation speed of the engine 2 (for example, the rotation speed of the crankshaft), various temperatures of the engine 2, the accelerator operation amount (output demand), the vehicle state such as the vehicle speed, the storage amount of the vehicle power supply, etc. The control unit 90 performs operation control of the power system 1 based on the detection signals. The operation control includes the operation control of the engine 2, the control of the traction / regeneration (power generation) of the electric generator 4, etc.

[0094] Next, various operation modes of the power system 1 of the present embodiment are described. The power system 1 switches the possibility of power transmission between the engine 2 and the hydraulic pump 6 and between the engine 2 and the electric generator 4 by disconnecting and connecting the one-way clutch 23. When the one-way clutch 23 is in the connected state, power transmission can be performed between the engine 2 and the hydraulic pump 6 and between the engine 2 and the electric generator 4. When the one-way clutch 23 is in the disconnected state, power transmission cannot be performed between the engine 2 and the hydraulic pump 6 and between the engine 2 and the electric generator 4.

[0095] Figure 6~Figure 8 It is a configuration diagram of the power system 1 for explaining each operation mode when the one-way clutch 23 is in the connected state. Fig. 9 , Fig.10 It is a configuration diagram of the power system 1 for explaining each operation mode when the one-way clutch 23 is in the disconnected state.

[0096] The power system 1 can operate in the first connection operation mode, the second connection operation mode, and the third connection operation mode when the one-way clutch 23 is in the connected state. The power system 1 can operate in the first disconnection operation mode and the second disconnection operation mode when the one-way clutch 23 is in the disconnected state.

[0097] Figure 6 The first connection operation mode shown is a mode in which the hydraulic pump 6 and the motor generator 4 are driven by the engine 2. Specifically, the input shaft 22 is rotated in one direction by the engine 2, and the one-way clutch 23 (inner ring 51 and outer ring 52) is in a connection state. When the one-way clutch 23 is in a connection state, the output shaft 26 rotates with the rotation of the input shaft 22. Thus, the hydraulic pump 6 is driven and the hydraulic pressure can be supplied to the hydraulic actuator. When the one-way clutch 23 is in a connection state, the first gear 61 rotates with the rotation of the input shaft 22. Then, the driving force of the first gear 61 is transmitted to the second gear 62, and the transmission shaft 24 rotates. As a result, the second drive pulley 82 rotates, and the driving force of the input shaft 22 is transmitted to the motor generator 4 via the second transmission mechanism 5. As a result, the motor generator 4 rotates, and the motor generator 4 generates electricity. The electric power generated by the motor generator 4 is charged to the vehicle power supply via the inverter 67.

[0098] Figure 7The second connection operation mode shown is a mode in which only the motor generator 4 is driven by the engine 2. In the second connection operation mode, similarly to the first connection operation mode, the driving force of the input shaft 22 is transmitted to the motor generator 4 via the relay mechanism 25 and the second transmission mechanism 5, so that the motor generator 4 generates electricity. In the second connection operation mode, the supply of hydraulic pressure is cut off between the hydraulic pump 6 and the hydraulic actuator. Therefore, even if the output shaft 26 rotates by the rotation of the input shaft 22, hydraulic pressure is not supplied to the hydraulic actuator.

[0099] Figure 8 The third connection operation mode shown is a mode in which the hydraulic pump 6 is driven by the engine 2 and the motor generator 4. When the engine 2 and the motor generator 4 are driven in a state where the rotation speed of the engine 2 (input shaft 22) is set to be higher than the rotation speed of the motor generator 4 (rotation shaft 75), the inner ring 51 wants to rotate in one direction relative to the outer ring 52. Therefore, the one-way clutch 23 is in a connection state. In this state, the driving force of the input shaft 22 is transmitted to the output shaft 26 via the one-way clutch 23. The driving force of the motor generator 4 is transmitted to the output shaft 26 via the second transmission mechanism 5 and the relay mechanism 25. As a result, the hydraulic pump 6 is operated by the driving force of the engine 2 and the motor generator 4.

[0100] Fig. 9 The first cut-off operation mode shown is a mode in which the hydraulic pump 6 is operated by inertia when the vehicle is traveling on a slope, etc. In this case, when the output shaft 26 rotates in one direction, the outer ring 52 and the first gear 61 are integrated and rotate in one direction. As a result, the driving force of the output shaft 26 is transmitted to the motor generator 4 via the relay mechanism 25 and the second transmission mechanism 5, and the motor generator 4 generates electricity. As the outer ring 52 rotates in one direction, the outer ring 52 and the inner ring 51 maintain a cut-off state. As a result, the outer ring 52 and the inner ring 51 rotate relative to each other, thereby restricting the input shaft 22 from rotating in the other direction due to the rotation of the output shaft 26.

[0101] Fig.10 The second cut-off operation mode shown is a mode in which the hydraulic pump 6 is driven only by the motor generator 4. When only the motor generator 4 is driven with the engine 2 stopped, the outer ring 52 is rotated in one direction via the second transmission mechanism 5 and the relay mechanism 25. When the outer ring 52 rotates in one direction, the one-way clutch 23 maintains the cut-off state. Therefore, only the output shaft 26 rotates with the rotation of the outer ring 52. That is, the hydraulic pump 6 operates with the rotation of the output shaft 26 while the input shaft 22 is restricted from rotating in the other direction.

[0102] As described above, in the power transmission unit of the present embodiment, the motor generator 4 is configured so as to be arranged radially outward with respect to the input shaft 22 when viewed in the axial direction.

[0103] According to this structure, compared with a structure in which the motor generator 4 and the engine 2 are arranged in the axial direction, it is possible to suppress the increase in the axial size (front-rear direction) of the power system 1 caused by the addition of the motor generator 4. As a result, in the existing engine compartment, the power system 1 for hybrid power can be mounted without increasing the size of the space for mounting the power system with only the engine in the front-rear direction. In this case, the motor generator 4 can also be installed after the existing power system to provide the power system 1 for hybrid power.

[0104] Moreover, in the present embodiment, the input shaft 22 and the output shaft 26 and the rotating shaft 75 are connected via a one-way clutch 23, and the one-way clutch 23 transmits the driving force of the input shaft 22 in one direction to the rotating shaft 75 and the output shaft 26 via the relay mechanism 25, and at the same time cuts off the driving force that causes the input shaft 22 to rotate in another direction based on the rotating shaft 75 and the output shaft 26 between the relay mechanism 25 and the input shaft 22.

[0105] According to this structure, the disconnection / connection state between the input shaft 22, the output shaft 26 and the rotating shaft 75 is switched by the rotation state of the input shaft 22, the output shaft 26 and the rotating shaft 75. Therefore, unlike other clutches, power is not required when switching the disconnection / connection state. As a result, energy loss can be suppressed to a minimum.

[0106] The power transmission unit of the present embodiment is configured such that the input shaft 22 and the output shaft 26 are coaxially arranged.

[0107] According to this structure, it is easy to ensure a space for arranging the motor generator 4 on the outer side in the radial direction with respect to the input shaft 22 and the output shaft 26 .

[0108] The power transmission unit of the present embodiment is configured such that the input shaft 22 is connected to the engine 2 outside the mechanism accommodating portion 32 , and is connected to the inner race 51 inside the mechanism accommodating portion 32 .

[0109] According to this structure, compared with a structure in which both end portions of the input shaft 22 are supported by bearings, the input shaft 22 can be made more compact in the axial direction.

[0110] The power transmission unit of the present embodiment is configured such that the one-way clutch 23 and the rotating shaft 75 are connected via the gears 61 and 62 .

[0111] According to this structure, the relay mechanism 25 having excellent reliability and durability in power transmission can be provided. In the power transmission unit of this embodiment, the relay mechanism 25 and the one-way clutch 23 are collectively accommodated in the mechanism accommodation portion 32, so the relay mechanism 25 and the one-way clutch 23 can be lubricated together.

[0112] The power transmission unit of the present embodiment is configured such that the first gear 61 is fixed to the first side (front) in the axial direction relative to the outer ring 52 , and the output shaft 26 is fixed to the second side (rear) in the axial direction relative to the outer ring 52 .

[0113] According to this configuration, motive power can be transmitted between the outer race 52 and the motor generator 4 and the hydraulic pump 6 while suppressing complication of the configuration.

[0114] The power transmission unit of the present embodiment is configured such that the motor generator 4 is arranged radially outwardly with respect to the mechanism accommodating portion 32 .

[0115] According to this structure, it is possible to suppress the mechanism housing portion 32 and the motor generator 4 from overlapping each other when viewed in the axial direction, thereby reliably suppressing an increase in the size of the power transmission unit in the axial direction.

[0116] In the power system 1 of the present embodiment, since the power transmission unit described above is provided, it is possible to provide the hybrid power system 1 which is compact in the axial direction.

[0117] (Other variations)

[0118] The preferred embodiments of the present invention are described above, but the present invention is not limited to these embodiments. Addition, omission, substitution and other changes of the structure can be made without departing from the scope of the present invention. The present invention is not limited by the above description, but only by the attached claims.

[0119] In the above embodiment, the input shaft 22 and the output shaft 26 are arranged coaxially, but the present invention is not limited to this structure. The input shaft 22 and the output shaft 26 may be arranged offset in the radial direction.

[0120] In the above embodiment, the power system 1 is mounted on the vehicle with the axial direction aligned with the front-rear direction, but the present invention is not limited to this structure. The power system 1 may be mounted on the vehicle with the axial direction aligned with the left-right direction, for example.

[0121] In the above-mentioned embodiment, the case where the cam type one-way clutch 23 is used has been described, but the one-way clutch 23 is not limited to the cam type, and a so-called overrunning type or the like may be used.

[0122] In the above embodiment, the relay mechanism 25 includes the first gear 61 and one second gear 62 . However, the relay mechanism 25 is not limited to this structure. The relay mechanism 25 may include a plurality of second gears 62 between the first gear 61 and the rotating shaft 75 .

[0123] In the above embodiment, the relay mechanism 25 is described as using the gears 61 and 62, but the present invention is not limited to this structure. The relay mechanism may also use a belt and a pulley. When a belt and a pulley are used, it is easy to set the reduction ratio between the input shaft 22 and the transmission shaft 24, and it is easy to transmit power even if the distance between the input shaft 22 and the transmission shaft 24 is far away.

[0124] In the above embodiment, the transmission shaft 24 is arranged between the input shaft 22 and the rotating shaft 75 , but the present invention is not limited to this structure. The input shaft 22 and the rotating shaft 75 may be directly connected via the relay mechanism 25 .

[0125] In the above embodiment, the input shaft 22 is described as being supported by the bearing 46 at a single point, but the present invention is not limited to this structure. The input shaft 22 may be supported by the bearing at two points.

[0126] In the above embodiment, the outer ring 52 is sandwiched between the first gear 61 and the output shaft 26, but the present invention is not limited to this structure. The connection structure between the relay mechanism 25 and the output shaft 26 and the one-way clutch 23 can be changed as appropriate.

[0127] In the above embodiment, the motor generator 4 is arranged radially outward relative to the mechanism housing portion 32 , but the present invention is not limited to this structure. The motor generator 4 only needs to be arranged radially outward relative to the input shaft 22 .

[0128] Furthermore, the components in the above-described embodiments may be appropriately replaced with known components without departing from the spirit of the present invention, and the above-described modifications may be appropriately combined.

[0129] Description of reference numerals:

[0130] 1: power system; 4: electric generator; 13: protruding shaft; 22: input shaft; 23: one-way clutch; 25: relay mechanism; 26: output shaft; 32: mechanism accommodating portion; 51: inner ring; 52: outer ring; 61: first gear; 62: second gear; 75: rotating shaft.

Claims

1. A power transmission unit comprising: an input shaft connected to a drive shaft of the internal combustion engine; An output shaft, which is connected to a driven device in a power-transmitting manner; a transmission mechanism connecting the input shaft and the output shaft; and a motor generator having a rotating shaft connected to the input shaft and the output shaft via the transmission mechanism, The transmission mechanism comprises: a relay mechanism connecting the rotating shaft and the output shaft; and a one-way clutch that transmits the driving force of the input shaft in one direction to the rotating shaft and the output shaft via the relay mechanism, and at the same time cuts off the driving force that rotates the input shaft in the other direction based on the rotating shaft and the output shaft between the relay mechanism and the input shaft, The motor generator is arranged on the outer side of the input shaft in a radial direction intersecting the axial direction, relative to the input shaft, when viewed in the axial direction of the input shaft.

2. The power transmission unit according to claim 1, characterized in that: The input shaft and the output shaft are coaxially arranged.

3. The power transmission unit according to claim 1 or 2, characterized in that: A mechanism accommodating portion for accommodating the transmission mechanism is provided, The one-way clutch comprises: Inner circle; an outer ring surrounding the inner ring and connected to the output shaft; and an intermediate member that connects the inner ring and the outer ring as the inner ring rotates in one direction, so that the inner ring and the outer ring rotate together, and releases the connection between the inner ring and the outer ring as the outer ring rotates in the other direction, so that the outer ring and the inner ring rotate relative to each other, The input shaft is rotatably supported by the mechanism housing portion at a middle portion in the axial direction. The input shaft is connected to the drive shaft outside the mechanism housing portion, and is connected to the inner ring inside the mechanism housing portion.

4. The power transmission unit according to claim 3, characterized in that: The relay mechanism has: a first gear fixed to the outer ring; and A second gear is disposed between the first gear and the rotating shaft.

5. The power transmission unit according to claim 4, characterized in that: The first gear is fixed to a first side in the axial direction relative to the outer ring. The output shaft is fixed to a second side in the axial direction relative to the outer ring.

6. The power transmission unit according to claim 1 or 2, characterized in that: A mechanism accommodating portion for accommodating the transmission mechanism is provided, The motor generator is arranged on the outer side in the radial direction relative to the mechanism accommodating portion.

7. A power system comprising: The power transmission unit according to claim 1 or 2; an internal combustion engine having a drive shaft to which the input shaft is connected; and A driven device includes a driven shaft connected to the output shaft.

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