JP2018200093A - Power transmission device including parking brake - Google Patents

Abstract

To provide a power transmission device capable of realizing both of intermittent connection of a second power source and parking lock, despite a simple and compact structure.SOLUTION: A power transmission device for outputting torque from a first power source and a second power source to an axle, comprises: a differential gear configured to differentially distribute torque to the axle; a first gear set drivingly connected to the first power source and the differential gear; a second gear set drivingly connected to the second power source; a stationary parking gear; and a clutch configured to selectively realize a first state of releasing the first gear set, a second state of connecting the first gear set to the second gear set, or a third state of connecting the first gear set to the parking gear.SELECTED DRAWING: Figure 2

Description

  The following disclosure relates to a power transmission device including a parking brake that is used to transmit torque to an axle in a vehicle in which two or more electric motors or combustion engines are combined.

  In recent years, vehicles that combine two or more power sources have appeared on the market in order to improve energy efficiency. A typical example is a so-called hybrid vehicle. The output of the combustion engine is used not only for driving the axle but also for charging the battery. In this case, the motor acts as a generator, and receives a part of the output of the combustion engine to generate electric power. In many cases, when the vehicle decelerates, the motor acts as a generator and regenerates the vehicle's inertia energy as electric power. That is, the torque needs to be exchanged in three directions via the clutch between two or more power sources and the axle. When trying to enable such power transmission, the device tends to be complex and large. Such a power transmission device preferably also includes a park lock mechanism. Since electric components for controlling these clutches and park lock mechanisms are also required, the power transmission device tends to be more complicated and large-scale.

  Patent Documents 1 and 2 disclose related techniques.

JP 2010-247786 A Japanese Patent Laying-Open No. 2015-054670

  Provided is a power transmission device capable of realizing both intermittent and park lock of a second power source in spite of being simple and compact.

  A power transmission device for outputting torque from the first power source and the second power source to the axle is drivably coupled to the differential for distributing torque differentially to the axle, and to the first power source and the differential. A first gear set, a second gear set drivingly coupled to a second power source, a fixed parking gear, a first state for freeing the first gear set, a first And a clutch configured to selectively realize a second state in which the gear set is connected to the second gear set and a third state in which the first gear set is connected to the parking gear.

  Preferably, the power transmission device further includes an actuator including a shift fork that is movable in the axial direction, and the shift fork realizes the first state at the first position and moves in the axial direction from the first position. The shift fork and the clutch are coupled so that the second state is realized at the second position and the third state is realized at the third position opposite to the second position with respect to the first position. ing. Also preferably, the clutch is movable in the axial direction by being splined to the hub, the hub drivingly connected to the first gear set, the teeth drivingly connected to the second gear set, and the shaft And a coupling sleeve that can mesh with either the tooth or the parking gear by moving in the direction. More preferably, the power transmission device further comprises a casing that encloses a single space and is dimensioned to accommodate the first and second gear sets, the differential, and the clutch in the space, and the actuator comprises: A cylinder disposed outside the casing is provided, and the shift fork extends from the cylinder, passes through the casing, and is coupled to the coupling. Further preferably, such a clutch further comprises a synchronizer interposed between the teeth and the hub to synchronize the teeth with the hub, but no synchronizer is interposed between the parking gear and the hub.

  In spite of being simple and compact, there is provided a power transmission device capable of realizing both intermittent and park lock of the second power source.

FIG. 1 is a general block diagram of a vehicle. FIG. 2 is a cross-sectional view of the power transmission device. FIG. 3 is a cross-sectional view of the power transmission device showing the vicinity of the clutch in an enlarged manner. 4A and 4B are cross-sectional views respectively showing (a) a state where the shaft is free from the ring gear and the parking gear, (b) a state where the shaft is connected to the ring gear, and (c) a state where the shaft is connected to the parking gear. It is.

  Several exemplary embodiments are described below with reference to the accompanying drawings.

  In each figure, F represents the front, A represents the rear, R represents the right, and L represents the left. However, these distinctions are merely for convenience of explanation, and the left and right are interchanged, or the front and rear are interchanged. Embodiments are possible.

  The power transmission device according to the present embodiment is used for transmitting torque in three directions between a first power source (electric motor), a second power source (combustion engine including a generator), and an axle. Applies to cars. 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, a vehicle generally includes a power transmission device 1 for driving front wheels and a gear box 13 for rear wheels. The power transmission device 1 includes a clutch 9 for controlling transmission of torque, and includes an actuator 11 for driving the clutch 9. The gear box 13 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) 15 is connected to each element via a wiring W to be electronically controlled. A battery 17 is connected to the ECU 15 to supply power to each element via the wiring W.

  An electric motor 3, a generator 5, and a combustion engine 7 are coupled to the power transmission device 1 as its constituent elements or external elements. The electric motor 3 is a main power source for driving the vehicle in this embodiment, and the combination of the combustion engine 7 and the generator 5 is a sub power source. As will be described in detail later, the electric motor 3 is always drivingly coupled to the front axle via a gear set, but the combination of the combustion engine 7 and the generator 5 is driven only when the clutch 9 is connected. Join.

  The combustion engine 7 is an auxiliary power source as described above, and drives the generator 5 to generate electric power. As is well known, a gasoline engine or a diesel engine can be used as the combustion engine 7, 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 generator 5 is used for charging the battery 17, and further supplied to the generator 5 itself, the electric motor 3, and various electrical components via the battery 17 and used for driving these. Further, power can be supplied to the generator 5 and used for starting the combustion engine 7.

  When the vehicle is braked, the electric motor 3 can be used for power generation to regenerate energy, or the generator 5 can be powered to drive the vehicle. That is, there is no essential difference in function between the electric motor 3 and the generator 5 except for the problem of capacity and dimensions.

  For example, the electric motor 3 and the generator 5 can be arranged on the same side with respect to the casing 21 of the power transmission device 1, and the combustion engine 7 can be arranged on the opposite side. These axes can also be parallel to each other. The actuator 11 for operating the clutch 9 can be disposed, for example, on the same side as the electric motor 3 and the generator 5 and below it, but is not necessarily limited thereto. Of course, these arrangements can be variously modified in place of the illustrated ones.

  Referring to FIG. 2, the power transmission apparatus 1 generally includes a first gear set 45 that is drivingly coupled to the electric motor 3, and a differential 47 that differentially distributes torque to the right and left front axles. And a second gear set 49 that is drivingly coupled to the combustion engine 7 and the generator 5, and a clutch 9 that severably connects the second gear set 49 to the differential 47.

  All of these are housed in the casing 21 in a liquid-tight manner. The casing 21 can be divided into two or more and can be coupled to each other by bolts or the like. When coupled, the casing 21 encloses a single space, in which each shaft, the differential 47, the gear sets 45 and 49, and the clutch 9 are accommodated and rotatably supported. There are several openings for coupling with the axle and the power source, but these can be sealed in a liquid-tight manner by appropriate sealing means so that the internal lubricating oil does not leak. The actuator 11 may be inside the casing 21, or may protrude to the outside and only the shift fork 33 for operating the clutch 9 extends from the actuator 11, penetrates the casing 21, and is recessed into the inside. .

  The side gears of the differential 47 respectively face both sides of the casing 21 of the power transmission device 1 and are splined to the right and left front axles, respectively. In FIG. 2, the differential 47 is a bevel gear type differential gear set, but may be any type of differential gear set, such as a face gear type or a helical gear type, or instead of the differential gear set, left and right axles may be used. A clutch pack that can be controlled independently may be used.

  Referring to FIG. 3, the clutch 9 generally includes a shaft 23 rotatably supported by the casing 21, a hub 25 that rotates integrally with the shaft 23, and a ring gear that is rotatable relative to the shaft 23. 41, a pinion 43 that rotates together with the shaft 23, and a parking gear 31 that is fixed or prevented from rotating around the casing 21.

  The ring gear 41 is always drivingly connected to the second gear set 49, and the pinion 43 is always drivingly connected to the differential 47 and the first gear set 45, but the clutch 9 connects the hub 25 to the ring gear. Unless connected to 41, the first gear set 45 is free from the second gear set 49. When the clutch 9 connects the hub 25 to the ring gear 41, the second gear set 49 (that is, the combination of the combustion engine 7 and the generator 5) is drivingly coupled to the differential 47. On the other hand, when the clutch 9 connects the hub 25 to the parking gear 31, the differential 47 cannot be rotated via the shaft 23, that is, the vehicle is parked.

  That is, the clutch 9 has a first state in which the first gear set 45 is free, a second state in which the first gear set 45 is connected to the second gear set 49, and the first gear set 45. The third state of being connected to the parking gear 31 is selectively realized. Such a clutch 9 may have various modes. For example, according to the illustrated example, the clutch 9 further includes a coupling sleeve 27 splined to the outer periphery of the hub 25. Since the spline is cut parallel to the axial direction of the shaft 23, and the shift fork 33 is engaged with the coupling sleeve 27 so as to allow the rotation thereof, the coupling sleeve is operated according to the operation of the actuator 11. 27 moves in the axial direction. As shown in FIG. 4A, the shaft 23 is free from the ring gear 41 and the parking gear 31 when the coupling sleeve 27 is in the neutral position.

  In this specification and the appended claims, unless otherwise specified, the axial direction means the axial direction of the shaft 23, and as will be described later, the axial direction of each shaft including the shaft 23 Can be substantially identical to each other.

  The ring gear 41 comprises a cone 29 which is integral or separate and fixed thereto, for example by spline coupling, which cone 29 comprises teeth 29a. The teeth 29 a are spline teeth so as to mesh with the spline teeth of the coupling sleeve 27. As shown in FIG. 4B, when the shift fork 33 moves the coupling sleeve 27 to the cone 29 side, the coupling sleeve 27 meshes with the teeth 29a, so that the hub 25 is connected to the ring gear 41.

  Since both the hub 25 and the ring gear 41 are rotating members and there is a difference in peripheral speed between them, a synchronizer ring 35 is interposed between the hub 25 and the cone 29 so as to absorb the difference in peripheral speed. Good. The synchronizer ring 35 generates friction in both the hub 25 and the cone 29 in accordance with the movement of the coupling sleeve 27 and prior to meshing with the teeth 29a, and synchronizes by absorbing the difference in peripheral speed between the two. That is, the combination of the sleeve 27, the hub 25, the ring 35, and the cone 29 constitutes a synchronizer that connects the hub 25 and the cone 29 after synchronizing them. The synchronizer may be a single cone type or, of course, a double cone type. Alternatively, the hub 25 and the cone 29 may be synchronized by another appropriate configuration.

  The parking gear 31 is fixed to the casing 21 or prevented from rotating as described above. Preferably, the parking gear 31 is coaxial with the shaft 23 and is fitted to the outer periphery of a race that supports one bearing of the shaft 23, for example. Further, the parking gear 31 includes teeth 31 a, which are substantially symmetrical with the teeth 29 a with respect to the hub 25, and can be engaged with the coupling sleeve 27. As shown in FIG. 4C, when the shift fork 33 moves the coupling sleeve 27 to the parking gear 31 side, the coupling sleeve 27 meshes with the teeth 31a, so that the hub 25 cannot rotate. Synchronizer ring may be interposed as described above, but can be omitted. When the vehicle is parked, the differential 47 and the shaft 23 are normally stopped, so the peripheral speed difference does not become a problem.

  One or both of the connection between the hub 25 and the ring gear 41 and the connection between the hub 25 and the parking gear 31 may be performed by dog teeth independent from the spline, engagement by a latch or ratchet, or friction instead of meshing by the spline teeth. Also good. In any case, the coupling sleeve 27 or a component corresponding to the coupling sleeve 27 moves in the axial direction shown in FIGS. To realize.

  Only in the state shown in FIG. 4B, the combustion engine 7 is drivingly connected to the differential 47, and its torque is used for both driving of the vehicle and power generation. In the state shown in FIG. 4 (a) or (c), the combustion engine 7 is free from the differential 47, and its torque is exclusively used for power generation by the generator 5, or can be stopped regardless of the traveling of the vehicle.

  Returning to FIG. 2, the cylinder 19 can be used to drive the actuator 11. The cylinder 19 may be arranged inside the casing 21, but can be arranged outside the casing 21. Further, the casing 21 can be disposed on the opposite side of the combustion engine 7 and can be disposed on the same side as the electric motor 3 and the generator 5 and below them. Even if the position is outside the casing 21, it is relatively difficult to interfere with an external device, and the layout is rarely restricted. Of course, other arrangements can be selected.

  The cylinder 19 includes a mechanism such as a ball screw, a crank, or a cam coupled to an electric motor, for example, and generates a linear motion in the shift fork 33 in response to the application of electric power. Alternatively, instead of such a mechanism, an electric motor such as a linear motor that directly generates linear motion may be used, or a hydraulic cylinder such as hydraulic pressure or pneumatic pressure may be used. In any case, the shift fork 33 moves forward or backward in the axial direction according to the input of electric power.

  According to the combination of the clutch 9 and the actuator 11 described above, both intermittent and parked power transmission can be realized only by the forward and backward movements of the single cylinder 19. This makes it possible to simplify the structure of the power transmission device 1. Further, since it is not necessary to prepare a control device for the clutch and a control device for the park lock independently, it is possible to simplify the electrical components for the control. Further, since the cylinder 19 can be driven at any time using the electric power stored in the battery 17, the clutch 9 can be driven even when the vehicle is stopped or the combustion engine 7 is stalled. Further, the clutch 9 does not unintentionally cancel the park lock in order to maintain the state even when the power is cut off.

  The actuator 11 does not need to be driven only by the operation of the cylinder 19 and may be returned to a specific position by using a projectile such as a coil spring or a leaf spring. For example, if a projectile is arranged to urge the shift fork 33 toward the neutral position, the clutch 9 automatically returns to the state shown in FIG. Alternatively, if a projectile is arranged to return to the state of FIG. 4C, it can be expected that a park lock is always made when the power is turned off.

  A ring gear 41 is fitted to the shaft 23 so as to be able to rotate relative thereto, and a bearing such as a needle bearing may be interposed therebetween. The ring gear 41 meshes with the second gear set 49. Further, a pinion 43 that meshes with the ring gear 48 of the differential 47 is splined to the shaft 23, and this may be arranged so as to be adjacent to the ring gear 41 in the axial direction. The pinion 43 meshes with a ring gear 48 included in the differential 47 or the first gear set 45.

  The shaft 23 can be made hollow for the purpose of weight reduction, for example. In order to utilize such a cavity for supplying lubricating oil to the bearing, one or more through holes may extend radially from the cavity toward the bearing. Lubricating oil is supplied to the bearing using the centrifugal force generated by the shaft 23.

  The power transmission device 1 includes a first drive shaft 51 that is drivingly coupled to the electric motor 3, and one end thereof faces the outside of the casing 21. Such one end may be provided with a spline for coupling. The first drive shaft 51 also includes the pinion 52 as a single body or as a separate body, and is drivingly coupled to a ring gear 48 included in the differential 47. Between them, an intermediate shaft 55 provided with a ring gear 56 and a pinion 50 may be interposed. These gears engaged with each other constitute a first gear set 45. Helical gears can be applied to these gears, or other types such as spur gears may be used.

  In order to operate the electric motor 3 in a higher rotation range, the first gear set 45 can be a reduction gear. The first gear set 45 rotates the differential 47 via the ring gear 48, so that the torque of the electric motor 3 is differentially distributed to the right and left front axles.

  The power transmission device 1 also includes a second drive shaft 57, one end of which is drawn out of the casing 21 and coupled to the combustion engine 7. Such one end may be provided with a spline for coupling. Other devices such as a dry clutch and a torque damper may be interposed between the combustion engine 7 and the shaft 57.

  The generator 5 is coupled to the second drive shaft 57 directly or to a driven shaft 59 that is separate from the second drive shaft 57. The driven shaft 59 may also have a spline at one end thereof. The drive shaft 57 includes a ring gear 58 as a single body or as a separate body, and the driven shaft 59 includes a pinion 60 that meshes with the ring gear 58, which constitute a second gear set 49. Helical gears or other types can be applied to these gears.

  In order to operate the generator 5 in a higher rotation range, the second gear set 49 can also be a reduction gear when viewed from the generator 5. When viewed from the combustion engine 7, the second gear set 49 can be a constant speed or a speed increasing gear.

  All these shafts can be parallel to each other and the gears can be arranged near a plane perpendicular to these shafts. Therefore, the entire power transmission device 1 can be made extremely small in the width direction. Further, it is not necessary to arrange these shafts on a single horizontal plane. For example, the first drive shaft 51 and the second drive shaft 57 are arranged on the upper side, and the differential 47 and the shaft 23 of the clutch 9 are arranged on the lower side. be able to. As a result, the shafts 51 and 57 are brought close to each other, so that the entire power transmission device 1 can be reduced both in the front-rear direction and in the vertical direction.

  According to the above-described embodiment, a large oil pump is not required to operate the clutch, and an oil path for introducing the hydraulic pressure into the clutch is not required. Therefore, the power transmission device 1 is simple and compact. Yes, especially around the clutch can be made compact. This significantly improves the design freedom on the vehicle side.

  Further, according to the power transmission device 1 described above, the second power source (for example, the combustion engine and the generator) is also changed from the state shown in FIG. 4 (a) in which only the first power source (for example, the electric motor) drives the vehicle. It is possible to shift to the state shown in FIG. 4B in which driving is performed by simply driving the actuator 11 in the axial direction, and further by driving the actuator 11 in the reverse direction, the park lock shown in FIG. It is also possible to transition to the state. Since these three states can be realized by only one actuator and it is not necessary to prepare a park lock mechanism separately, the apparatus can be made simple and compact. Further, since only one actuator needs to be controlled, electrical components for control can be simplified, and the power transmission device can be further simplified and compact.

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

  In spite of being simple and compact, there is provided a power transmission device capable of realizing both intermittent and park lock of the second power source.

DESCRIPTION OF SYMBOLS 1 Power transmission device 3 Electric motor 5 Generator 7 Combustion engine 9 Clutch 11 Actuator 13 Gear box 15 Electric control unit (ECU)
17 Battery 19 Electric cylinder 21 Casing 23 Shaft 25 Hub 27 Coupling sleeve 29 Cone 29a Teeth 31 Parking gear 31a Teeth 33 Shift fork 35 Synchronizer ring 41 Ring gear 43 Pinion 45 First gear set 47 Differential 48 Ring gear 49 Second gear set 50 Pinion 51 First drive shaft 52 Pinion 55 Intermediate shaft 56 Ring gear 57 Second drive shaft 58 Ring gear 59 Driven shaft 60 Pinion F Front A Rear R Right L Left W Wiring

Claims (5)

A power transmission device that outputs torque from a first power source and a second power source to an axle,
A differential that differentially distributes the torque to the axle;
A first gear set drivingly coupled to the first power source and the differential;
A second gear set drivingly coupled to the second power source;
A fixed parking gear,
A first state in which the first gear set is free; a second state in which the first gear set is connected to the second gear set; and the first gear set is connected to the parking gear. A clutch configured to selectively implement the third state of
Power transmission device with An actuator having a shift fork movable in the axial direction;
The first state is realized at the first position of the shift fork, the second state is realized at the second position moved in the axial direction from the first position, and the shift fork is related to the first position. 2. The power transmission device according to claim 1, wherein the shift fork and the clutch are coupled to achieve the third state at a third position opposite to the second position.   The clutch includes a hub drivingly coupled to the first gear set, a tooth drivingly coupled to the second gear set, a spline coupled to the hub, and is movable in an axial direction. The power transmission device according to claim 2, further comprising a coupling sleeve capable of meshing with either the tooth or the parking gear by moving in a direction. Further comprising a casing dimensioned to enclose a single space and to accommodate the first and second gear sets, the differential, and the clutch in the space;
The actuator includes a cylinder disposed outside the casing, and the shift fork extends from the cylinder, passes through the casing, and is coupled to the coupling sleeve.
The power transmission device according to claim 3.   The clutch further includes a synchronizer that is interposed between the teeth and the hub to synchronize the teeth with the hub, and no synchronizer is interposed between the parking gear and the hub. Power transmission device.

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