JP6592203B2 - Power transmission device - Google Patents

Description

  The following disclosure relates to a power transmission device for transmitting torque to an axle in a vehicle in which two or more electric motors or combustion engines are combined.

  In recent years, so-called hybrid vehicles combining two or more power sources have appeared on the market in order to improve energy efficiency. The power source is, for example, a combination of a combustion engine and an electric motor. The output of the combustion engine can be used to drive the axle, or it can be used exclusively for power generation. The motor is driven by the electric power stored in the battery and used to drive the axle. When the vehicle decelerates, the motor may be used as a generator to regenerate inertia energy as electric power. Alternatively, the vehicle may be equipped with a generator independent of the motor.

  Patent Document 1 discloses a related technique.

Japanese Patent Publication No. 2009-072052

  According to FIG. 1 of Patent Document 1, it seems that the combustion engine including the generator is disposed in front of the axle and the motor / generator is disposed in rear of the axle. The generator and the combustion engine are arranged on the right side of the power transmission device, and the motor / generator is arranged on the left side. That is, these devices consume the space in the engine room significantly both vertically and horizontally. Furthermore, since the combustion engine is heavier than the motor / generator, the center of gravity of the vehicle may be biased to the right from the center. As understood from this example, how to arrange a plurality of power sources in a narrow engine room and how to ensure a weight balance are important technical problems in a hybrid vehicle. The apparatus disclosed in the present specification has been devised in view of such a problem.

  According to one aspect, the power transmission device that outputs torque from the first power source and the second power source to the first and second axles has a first side and a first side facing the first side. A casing that surrounds a single space, a differential that is accommodated in the casing and that differentially distributes the torque to the first axle and the second axle, and the first A first port formed on one side and fixedly coupled to the first power source to position the rotor shaft of the first power source coaxially with the rotational axis of the differential; and Parallel to the axle and the second axle, geared to the differential and partially pulled out of the casing from the first side for gearing to the rotor shaft of the second power source. The first shaft and the first shaft A second port fixedly coupled to the second power source, parallel to the first axle and the second axle, and a drive shaft of the second power source A second shaft facing the first side or partially pulled out of the casing from the first side to be coupled to the casing, and accommodated in the casing, wherein the second shaft is used as the differential. And a clutch that is gear-coupled so as to be cut off.

FIG. 1 is a general block diagram of a vehicle. FIG. 2 is a cross-sectional view of a power transmission device according to an embodiment cut along a plane passing through an axle. FIG. 3 is a cross-sectional view showing an enlarged clutch. FIG. 4 is a cross-sectional view of a clutch according to another example. FIG. 5 is a cross-sectional view of a power transmission device according to another embodiment, mainly showing an enlarged view of the first shaft and the clutch. FIG. 6 is a cross-sectional view of a power transmission device according to still another embodiment, mainly showing an enlarged view of the first shaft and the clutch.

  Several exemplary embodiments are described below with reference to FIGS.

  In each figure, F represents the front, A represents the back, R represents the right, L represents the left, U represents the top, and D represents the bottom. These distinctions are merely for convenience of explanation. Embodiments in which left and right are interchanged or front and rear are interchanged are possible.

  The power transmission device according to the present embodiment is used for the purpose of transmitting torque in three directions between the first power source (electric motor), the second power source (combustion engine), and the right and left axles. Applies to hybrid vehicles. The electric motor can also act as a generator, and the generator may be included in the combustion engine, but may include a generator independently of these. Although FIG. 1 shows an example in which the power transmission device is applied to the front axle of a hybrid vehicle, it can of course be applied to the rear axle.

  Referring to FIG. 1, the vehicle generally includes a power transmission device 1 for driving front wheels and a gear box 15 for rear wheels. The gear box 15 includes a differential that allows a differential between the right and left axles, but may further include an electric motor or other device that drives the rear wheels. In addition, an electric control unit (ECU) 11 is connected to each element through a wiring W to be electronically controlled. A battery 13 is connected to the ECU 11, and power is supplied to each element via the wiring W.

  An electric motor 3 and a combustion engine 5 are coupled to the power transmission device 1 as constituent elements or external elements. The generator 7 may be included in the combustion engine 5 or may be drivingly coupled to the combustion engine 5 via the power transmission device 1 as shown. The electric motor 3 is a main power source that drives the vehicle in the present embodiment, and the combustion engine 5 is a sub power source. As will be described in detail later, the electric motor 3 is always coupled to the front axle via a gear set, but the combustion engine 5 is only coupled to the clutch 59 when the clutch 59 is engaged.

  As is well known, a gasoline engine or a diesel engine can be used as the combustion engine 5, but other types of internal combustion engines may be used or, if possible, an external combustion engine. Also good.

  The electric power generated by the electric motor 3 and / or the generator 7 is used for charging the battery 13, and further supplied to the electric motor 3 itself, the generator 7 and various electrical components via the battery 13, and used for driving these. The

  When braking the vehicle, the electric motor 3 can be used for power generation to regenerate energy, and the generator 7 can be powered to drive the vehicle. That is, there is no essential difference in function between the electric motor 3 and the generator 7 except for the problem of capacity and dimensions.

  Referring to FIG. 2, the power transmission device 1 includes a casing 21 that encloses a space therein. The casing 21 extends thinly and long in the vertical direction, and can be distinguished into a right side 21A and a left side 21B. The casing 21 may be divided into these two parts, or may be divided into more parts. Each shaft, each gear, differential, and clutch, which will be described later, are generally accommodated in a space surrounded by the casing 21.

  A port P1 for fixing the electric motor 3 and a port P2 for fixing the combustion engine 5 are formed on the same side with respect to the casing 21, for example, the right side 21A. Of course, both may be formed on the left side 21B. That is, the electric motor 3 and the combustion engine 5 are arranged on the same side with respect to the power transmission device 1. A plurality of bolts can be used for fixing, and the ports P1, P2 can be provided with a plurality of bolt holes therefor, or the fixing can be done by fitting or other methods.

  The power transmission device 1 includes a differential 27 that differentially distributes torque to the right and left axles inside the casing 21. A bevel gear type differential gear set can be applied to the differential 27 as shown in the figure, or any type of differential gear set such as a face gear type or a helical gear type may be used. The rotation shaft OX is directed in the width direction of the power transmission device 1, and the pair of side gears respectively face both sides 21 </ b> A and 21 </ b> B of the casing 21 and are splined to the right and left axles, respectively.

  The port P1 is positioned so that the axis of the rotor shaft 31 of the electric motor 3 is coaxial with the rotation axis OX. That is, when the electric motor 3 is coupled to the port P1 via the bracket 21C, the port P1 is positioned so that the rotor shaft 31 is necessarily coaxial with the differential 27.

  The rotor shaft 31 is hollow, and the axle passes through the rotor shaft 31 and is coupled to the side gear. It should be noted here that the rotor shaft 31 and the differential 27 are not directly coupled to each other, and an appropriate gap is maintained between them so that the axle can rotate independently of the rotor shaft 31. It is.

  An intermediate shaft 33 mediates between the rotor shaft 31 and the differential 27. The intermediate shaft 33 is partially pulled out of the casing 21 from the right side 21A (or the left side 21B) of the casing 21, and includes a ring gear 24 fixedly at the end. Correspondingly, the rotor shaft 31 is fixedly provided with a pinion 22 at one end thereof, and the rotor shaft 31 is gear-coupled to the intermediate shaft 33 by meshing them. The differential 27 includes a ring gear 27C, and the intermediate shaft 33 includes a pinion 26 corresponding to the ring gear 27C, and the intermediate shaft 33 is gear-coupled to the differential 27 by meshing them.

  That is, the rotor shaft 31 is always gear-coupled to the differential 27 via the intermediate shaft 33. Therefore, the torque of the electric motor 3 is always output to the axle. Or what is called a free running differential may be employ | adopted for the differential 27, and torque may be made intermittent.

  The ring gear 24 can have a larger diameter than the pinion 22. That is, the gear coupling among the rotor shaft 31, the intermediate shaft 33 and the differential 27 constitutes a reduction gear set. This makes it possible to operate the electric motor 3 in a higher rotation range, and thus to extract a large thrust from the electric motor 3.

  The casing 21 is not closed around the intermediate shaft 33, and does not prevent the internal lubricating oil from leaking from such a portion unless there is a seal. In the present embodiment, this is rather utilized to circulate the lubricating oil in the casing 21 to the bearings in the bracket 21C and the electric motor 3 to lubricate them. In order to facilitate the circulation of the lubricating oil, the intermediate shaft 33 can be hollow, and the ring gear 24 can have one or more through holes. For the circulation of the lubricating oil, pressurization by a pump 17 which will be described later can be used. However, instead of or in addition to this, other circulation means may be provided.

  The power transmission device 1 includes a drive shaft 37 for drivingly coupling with the combustion engine 5 inside the casing 21. The rotation axis EX is also directed in the width direction of the power transmission device 1, that is, the rotation axes OX and EX can be parallel to each other.

  The port P2 is positioned to align the axis of the drive shaft of the combustion engine 5 with the rotation axis EX. The drive shaft 37 faces the right side 21 </ b> A (or the left side 21 </ b> B) of the casing 21, or is partially pulled out from the casing 21, and is coupled to the drive shaft of the combustion engine 5 at this end. For example, a spline can be used for the connection.

  The drive shaft 37 is not always gear-coupled to the differential 27. The power transmission device 1 includes a clutch 59 so that the drive shaft can be geared to the differential 27 so as to be cut off. That is, the combustion engine 5 participates in driving the axle only when the clutch 59 is engaged. The clutch 59 may be a multi-plate clutch, another appropriate friction clutch, or a clutch such as a spline, dog or synchro cone. An example using a multi-plate clutch will be described below.

  The clutch 59 includes a shaft 53 and first and second ring gears 43 and 41 fitted to the shaft 53. One of them is fixed with respect to the shaft 53, and the other can rotate relative to the other. Here, an example will be described in which the second ring gear 41 can rotate relatively.

  The drive shaft 37 includes a ring gear 28 so as to correspond to the ring gear 41, and the ring gears 28 and 41 mesh with each other. The ring gear 43 is gear-coupled to the ring gear 27C of the differential 27. Thus, when the clutch 59 is engaged, torque from the combustion engine 5 is transmitted to the axle via the differential 27.

  The ring gears 43 and 27C may be meshed directly, but for example, a counter gear 35 may be interposed. The presence of the counter gear 35 is useful for adjusting the distance between the axes EX and OX. Alternatively, if possible, the ring gear 24 or the pinion 26 of the intermediate shaft 33 may be interposed between them instead of or in addition to the counter gear 35.

  The ring gear 28 can be made larger in diameter than the ring gear 41, that is, these gear combinations constitute a speed increasing gear set, and the rotation by the combustion engine 5 can be increased and transmitted to the axle.

  Referring to FIG. 3 in combination with FIG. 2, the clutch 59 includes a clutch drum 55 fixedly coupled to the shaft 53 and a clutch hub 57 fixedly coupled to the ring gear 41, which are coaxial. Is nested. A plurality of clutch plates respectively coupled to the clutch drum 55 and the clutch hub 57 are alternately arranged, and the plurality of clutch plates constitute a multi-plate clutch. When a pressing force is applied to the clutch 59 in the axial direction, a frictional force acts on the multi-plate clutch, and the second ring gear 41 is drivingly coupled to the first ring gear.

  In order to exert a pressing force on the clutch 59, fluid pressure such as hydraulic pressure can be used. The example shown in FIG. 3 is an example in which a pump 17 and a third power source 19 such as an electric motor for driving the pump 17 are provided outside the casing 21 to generate pressurized fluid. May be.

  As the pump 17, any of a gear pump, a vane pump, or a plunger pump can be used. In any case, the protrusion of the pump 17 from the casing 21 can be made sufficiently smaller than the generator 7 and other elements.

  A reservoir 61 can be coupled to one end of the clutch 59 to store the pressurized fluid. A flow path led from the pump 17 is opened inside the reservoir 61 and is filled with the pressurized fluid supplied from the pump 17. Further, the reservoir 61 is further in fluid communication with the clutch drum 55 through, for example, a flow path 64 penetrating the shaft 53, so that the fluid pressure connects the multi-plate clutch. The reservoir 61 may further include an accumulator, which is advantageous for maintaining a constant pressure. This is advantageous in reducing the need for continuously operating the power source for pressurization and thus reducing energy loss.

  The pump 17 can be driven by a third power source such as an electric motor 19. Since the electric motor 19 can be driven at any time using the electric power stored in the battery 13, the clutch 59 can be driven even when the vehicle is stopped or the combustion engine 5 is stalled. This contributes to improving the response of the vehicle to the driver's operation, as the auxiliary power source can be immediately used for driving the vehicle as needed. Further, the driving of the clutch 59 can be directly controlled by turning on / off the electric power to the pump 17 and therefore does not require a valve for controlling the hydraulic circuit.

  Of course, an on / off valve may be used. In particular, when the on / off valve is combined with an accumulator, the operation of the electric motor 19 can be limited to contribute to the suppression of energy loss, and the operation of the clutch 59 can be made quick.

  Of course, the pump 17 may be driven by extracting a part of the torque from any shaft in the casing 21, for example, the shaft 53, regardless of the third power source.

  In the example of FIG. 3, the electric motor 19 and the pump 17 are disposed close to the clutch 59, but may be disposed at other appropriate positions. This makes it easy to select the arrangement of the electric motor 19 and the pump 17 so as to avoid interference by surrounding movable members. As illustrated in FIG. 6, since the power transmission device 1 does not protrude to the left from the clutch 59, the degree of freedom in layout is improved.

  For example, the pump 17 can be disposed at an appropriately low position in the casing 21 and outside or inside the left side 21B. Although the flow path must be extended from the pump 17 to the reservoir 61 for a long time, for example, the pressure loss can be suppressed by making the flow path substantially horizontal.

  Such a position is close to the lowest point in the casing 21 and is therefore an oil reservoir, and since the hydraulic oil after driving the clutch 59 has come down, it is convenient to suck it up by the pump 17. Further, such a position is extremely advantageous for cooling the electric motor 19 and the pump 17 because it can receive an air flow generated when the vehicle travels. The overall durability of the fluid pressure system including these is improved.

  The clutch 59 may be driven by mechanical means such as an electric motor or a cam mechanism, or electromagnetic means such as a solenoid, without using fluid pressure. FIG. 4 shows such an example. The motor 19 exerts a driving force in a direction toward the clutch 59, and this is mediated by a mechanical link (not shown) to connect / disconnect the clutch 59. As shown in the figure, a dog clutch can be used instead of the multi-plate clutch.

  As already described, the generator 7 (which can also be operated as a motor) may be included in the second power source (combustion engine) 5 or may be independent of this. FIG. 5 shows such an example.

  Referring to FIG. 5 in combination with FIGS. 1 and 2, the power transmission device 1 includes a driven shaft 39, one end of which faces, for example, the left side 21 </ b> B and can be coupled to the generator 7. For example, a spline can be provided outside or inside the one end for coupling. The driven shaft 39 includes a pinion 30 as a single body or a separate body so as to correspond to the ring gear 28 of the drive shaft 37, and is gear-coupled to the drive shaft 37. Alternatively, the pinion 30 may mesh with the ring gear 41 if possible. The generator 7 is driven by the second power source 5 to generate electric power, and the electric power is used for charging the battery 13. The generator 7 can also act as a motor by receiving electric power from the battery 13.

  Alternatively, as shown in FIG. 6, the generator 7 may be coaxial with the drive shaft 37 or may be coupled thereto. Further, as shown in FIG. 6, the generator 7 may be disposed on the right side 21 </ b> A in the same manner as the second power source 5. For example, the generator 7 is fixed in the port P <b> 2, and a shaft 71 that can rotate relative thereto is fixedly coupled to the rotor of the generator 7.

  The second power source 5 may drive the shaft 71 directly, but a speed increasing gear set for further speeding up the rotation of the second power source 5 may be interposed. FIG. 6 shows an example of a speed increasing gear set using a combination of a driven shaft and a coaxial shaft. For example, the drive shaft 37 may include a coaxial shaft 73 that is coaxial with the drive shaft 37 and may be rotatable independently of each other. The coaxial shaft 73 includes a pinion 75 fixedly or integrally.

  A driven shaft 39 that is gear-coupled to the drive shaft 37 forms part of the speed increasing gear set, and includes a ring gear 77 in addition to the pinion 30, which meshes with the pinion 75. The ring gear 77 has a diameter larger than that of the pinion 30, so that the rotation of the drive shaft 37 is increased and transmitted to the coaxial shaft 73. Since the coaxial shaft 73 is spline-coupled with the shaft 71 of the generator 7, that is, the rotation of the second power source 5 is accelerated and transmitted to the generator 7, and is used for power generation. Alternatively, when the generator 7 is operated as a motor, the speed increasing gear group acts as a speed reducing gear group and increases its output.

  Regardless of the arrangement of the generator 7, the connection between the second power source 5 and the drive shaft 37 may be via a torque damper 81. Alternatively, a dry clutch or other means may be interposed.

  In any embodiment, since the first power source is arranged coaxially with the axle, even if the second power source is in front of these, the whole is compact in the vertical direction. Moreover, as can be understood from the drawings, the power transmission device has only the same size as the combination of the first power source and the second power source in the vertical direction. Further, since the first power source and the second power source are arranged on the same side with respect to the power transmission device, the whole does not consume space in the lateral direction. Therefore, a relatively small space in the engine room of the vehicle can be used effectively.

  As schematically understood from FIG. 1, if the power transmission device is disposed slightly left (or right) with respect to the vehicle body, the relatively heavy first power source and second power source are It is arranged at the center in the width direction. This is extremely beneficial from the viewpoint of vehicle weight balance.

  Although several embodiments have been described, modifications or variations of the embodiments can be made based on the above disclosure.

  A power transmission device is provided that solves the problem of power source and power transmission layout and weight balance.

Claims (6)

A power transmission device that outputs torque from a first power source and a second power source to first and second axles,
A casing having a first side and a second side facing the first side and surrounding the space inside;
A differential housed in the casing and differentially distributing the torque to the first axle and the second axle;
A first port formed on the first side and fixedly coupled to the first power source to position the rotor shaft of the first power source coaxially with the rotational axis of the differential;
A portion that is parallel to the first axle and the second axle, geared to the differential, and out of the casing from the first side for gearing to the rotor shaft of the first power source. A first shaft pulled out automatically,
A second port formed on the first side and fixedly coupled to the second power source;
Parallel to the first axle and the second axle and facing the first side to be coupled to the drive shaft of the second power source, or a portion outside the casing from the first side A second shaft pulled out automatically,
A clutch housed in the casing and geared so that the second shaft can be cut into the differential;
Power transmission device with   The first shaft includes a pinion gear that is gear-coupled to the differential, and a gear that is larger in diameter than the pinion gear and gear-coupled to the rotor shaft, so that the pinion gear and the gear are decelerated. The power transmission device according to claim 1, constituting a gear set.   The clutch includes a first ring gear that is gear-coupled to the differential and a second ring gear that is gear-coupled to the second shaft, and the first ring gear and the second ring gear; The power transmission device according to claim 1, wherein the power transmission devices are coaxial and are configured to be coupled to each other when the clutch receives an axial pressing force. The said 2nd shaft is provided with a gear larger diameter than the said 2nd ring gear, Therefore The said 2nd shaft and the said 2nd ring gear comprise a speed-up gear set of Claim 3. Power transmission device. A pump that generates fluid pressure;
A flow path for fluidly connecting the pump and the clutch to use the fluid pressure as the pressing force;
The power transmission device according to claim 3, further comprising: A third power source that is independent of the first power source, the second power source, and the clutch and that is disposed outside the casing and is drivingly coupled to the rotary shaft of the pump;
The power transmission device according to claim 5, further comprising:

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