JP7170021B2 - Power transmission with parking brake - Google Patents

Description

The following disclosure relates to a drivetrain with parking brake used to transmit torque to axles in vehicles combining two or more electric motors or combustion engines.

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 to drive the axle, but also to charge the battery. At this time, the motor acts as a generator and receives part of the output of the combustion engine to generate electricity. Also, in many cases, the motor acts as a generator even when the vehicle decelerates, regenerating the inertial energy of the vehicle as electric power. That is, torque must be exchanged in three directions through clutches between two or more power sources and axles. Devices that attempt to enable such power transmission tend to be complex and bulky. Such drivetrains also preferably include a park lock mechanism. Since electrical components for controlling these clutches and parking lock mechanisms are also required, the power transmission system tends to be more complicated and larger in scale.

Patent Documents 1 to 3 disclose related techniques.

JP 2010-247786 A JP 2015-054670 A JP 2013-129329 A

To provide a power transmission device capable of realizing both the intermittent operation of a power source and a parking lock in spite of being simple and compact.

A power transmission device for outputting torque from a power source to an axle, comprising: a differential for differentially distributing the torque to the axle; a first gear set drivingly coupled to the differential; a second gear set drivingly coupled; a fixed parking gear; a first condition disengaging said first gear set from said second gear set; a clutch configured to selectively achieve a second state of coupling with a second gear set and a third state of coupling said first gear set with said parking gear; and axially movable. wherein the first state is realized at a first position, the second state is realized at a second position axially displaced from the first position, and the first state is realized at a second position. a shift fork coupled to the clutch to achieve the third condition at a third position opposite in position to the second position.

Preferably, said clutch has a hub drivingly connected to said first set of gears, teeth drivingly connected to said second set of gears, and splined to said hub for axial movement. and a coupling sleeve that is axially movable to engage either the teeth or the parking gear. More preferably, the power transmission device further includes an actuator configured to drive the shift fork axially from the first position to either the second position or the third position. More preferably, the power transmission device further comprises a casing that surrounds a single space and is sized to accommodate the first and second gear sets, the differential, and the clutch in the space, The actuator includes a cylinder located outside the casing, and the shift fork extends from the cylinder, penetrates the casing, and is coupled to the coupling sleeve. Also preferably, the clutch further includes a synchronizer interposed between the teeth and the hub for synchronizing the teeth with the hub, and no synchronizer is interposed between the parking gear and the hub.

Provided is a power transmission device that is simple and compact, yet can realize both the intermittent operation of a power source and the parking lock.

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 an enlarged view of the vicinity of the clutch. FIG. 4 is a sectional view showing (a) a state in which the shaft is free from the ring gear and the parking gear, (b) a state in which the shaft is connected to the ring gear, and (c) a state in which the shaft is connected to the parking gear. is.

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

In each figure, F indicates the front, A indicates the rear, R indicates the right, and L indicates the left. Embodiments are possible.

The power transmission device according to the present embodiment is used to transmit 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 also be applied to the rear axle.

Referring to FIG. 1, the vehicle generally comprises a power transmission 1 for driving the front wheels and a gearbox 13 for the rear wheels. The power transmission device 1 incorporates a clutch 9 for controlling transmission of torque, and is provided with an actuator 11 for driving it. Gearbox 13 includes a differential to allow differential between the right and left axles, but may also include an electric motor or other device to drive the rear wheels. An electric control unit (ECU) 15 is connected via wiring W to each element for electronic control. A battery 17 is connected to the ECU 15 and supplies electric power to each element through wiring W.

An electric motor 3 , a generator 5 and a combustion engine 7 are connected to the power transmission device 1 as its components or as external elements. The electric motor 3 is the main power source for driving the vehicle in this embodiment, and the combination of the combustion engine 7 and the generator 5 is the auxiliary power source. Although the electric motor 3 is always drivingly connected to the front axle via a gear set, the combination of the combustion engine 7 and the generator 5 is driven only when the clutch 9 is engaged. physically connect.

The combustion engine 7 is a secondary power source as already described, and drives the generator 5 to generate electricity. Combustion engine 7 may, as is well known, be a gasoline engine or a diesel engine, but may also utilize other types of internal combustion engines, or possibly external combustion engines. good too.

The electric power generated by the generator 5 is used to charge the battery 17, is supplied to the generator 5 itself, the electric motor 3 and various electrical components via the battery 17, and is used to drive them. It is also possible to supply electric power to the generator 5 and use it to start the combustion engine 7 .

When the vehicle is braked, the electric motor 3 is used for power generation to regenerate energy, and it is also possible to supply power to the generator 5 to drive the vehicle. That is, aside from capacity and size issues, there is no essential difference between the electric motor 3 and the generator 5 in terms of function.

The electric motor 3 and the generator 5 can, for example, be arranged on the same side with respect to the casing 21 of the transmission 1 and the combustion engine 7 can be arranged on the opposite side. Also, these axes can be parallel to each other. The actuator 11 for operating the clutch 9 can be arranged, for example, on the same side as the electric motor 3 and the generator 5 and below them, but it is not necessarily limited to this. Of course, these arrangements can be modified in various ways in place of what is illustrated.

Referring to FIG. 2, the driveline 1 generally includes a first set of gears 45 drivingly coupled to the electric motor 3 and a differential 47 differentially distributing torque to the right and left front axles. , a second gear set 49 drivingly connected to the combustion engine 7 and the generator 5 , and a clutch 9 disconnectably connecting the second gear set 49 to the differential 47 .

All of these are housed in a casing 21 in a liquid-tight manner. The casing 21 can be divided into two or more parts, which can be joined together by bolts or the like. When coupled, casing 21 encloses a single space in which each shaft, differential 47, gear set 45, 49, and clutch 9 are housed and rotatably supported. Although there are several openings for connection with axles and power sources, these can be sealed in a liquid-tight manner by suitable sealing means so that the lubricating oil inside does not leak. The actuator 11 may be inside the casing 21, or may protrude outside thereof, and only the shift fork 33 for operating the clutch 9 may extend from the actuator 11, penetrate the casing 21, and be recessed inside thereof. .

The side gears of the differential 47 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 it may be a differential gear set of any type such as a face gear type or a helical gear type. independently controllable clutch packs may be utilized.

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

Ring gear 41 is permanently drivingly connected to second gear set 49, and pinion 43 is permanently drivingly connected to differential 47 and first gear set 45, while clutch 9 engages hub 25 with ring gear. The first gear set 45 is free from the second gear set 49 as long as it is not connected to 41 . A second gear set 49 (i.e., combustion engine 7 and generator 5 combination) is drivingly coupled to differential 47 when clutch 9 couples hub 25 to ring gear 41 . On the other hand, when the clutch 9 connects the hub 25 to the parking gear 31, the differential 47 cannot rotate through the shaft 23, that is, the vehicle is park-locked.

That is, the clutch 9 is in a first state in which the first gear set 45 is free, in a second state in which the first gear set 45 is connected to the second gear set 49, and in the first gear set 45. It is configured to selectively realize a third state in which the parking gear 31 is connected. Although such a clutch 9 can take various forms, for example according to the example shown, the clutch 9 further comprises a coupling sleeve 27 splined to the outer periphery of the hub 25 . 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 its rotation. 27 moves axially. As shown in FIG. 4(a), 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 scope of 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, integrally or separately and fixed thereto, for example by a splined connection, such cone 29 being provided with teeth 29a. The teeth 29a are spline teeth to mesh with the spline teeth of the coupling sleeve 27. As shown in FIG. When the shift fork 33 moves the coupling sleeve 27 toward the cone 29 as shown in FIG.

Both the hub 25 and the ring gear 41 are rotating members, and there is a peripheral speed difference therebetween. good. The synchronizer ring 35 generates friction between the hub 25 and the cone 29 as the coupling sleeve 27 moves and prior to meshing with the teeth 29a, and absorbs the peripheral speed difference between them to synchronize them. That is, the combination of the sleeve 27, hub 25, ring 35, and cone 29 constitutes a synchronizer that synchronizes the hub 25 and cone 29 and then connects them. The synchronizer may be of a single cone type or of course a double cone type. Alternatively, hub 25 and cone 29 may be synchronized by any other suitable configuration.

The parking gear 31 is fixed or detented to the casing 21 as already described. Parking gear 31 is preferably coaxial with shaft 23 and fits, for example, on the outer periphery of a race supporting one bearing of shaft 23 . The parking gear 31 is also provided with teeth 31 a , similar to the ring gear 41 and substantially symmetrical to the teeth 29 a with respect to the hub 25 , and is meshable with the coupling sleeve 27 . As shown in FIG. 4(c), when the shift fork 33 moves the coupling sleeve 27 toward the parking gear 31, the coupling sleeve 27 meshes with the teeth 31a, thereby rendering the hub 25 unrotatable. A synchronizer ring may be interposed as described above, but may be omitted. When the vehicle is park-locked, the differential 47 and the shaft 23 are normally stopped, so the circumferential speed difference does not matter.

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 can be replaced by engagement by dog teeth independent of the splines, engagement by a latch or ratchet, or by friction instead of engagement by spline teeth. good too. In any event, the coupling sleeve 27 or equivalent component is moved in the axial direction shown in FIGS. Realize

Only in the state shown in FIG. 4(b) is the combustion engine 7 drivingly coupled to the differential 47 and its torque is used both to drive the vehicle and to generate electricity. 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 running of the vehicle.

Referring back to FIG. 2, cylinder 19 may be utilized to drive actuator 11 . The cylinder 19 may be arranged inside the casing 21 , but can also be arranged outside the casing 21 . It can also be arranged on the opposite side of the casing 21 from the combustion engine 7 or on the same side as the electric motor 3 and the generator 5 but below them. Even if such a position is outside the casing 21, it is relatively unlikely to interfere with external devices, and the layout is less restricted. Of course other arrangements can be chosen.

Cylinder 19 has a mechanism such as a ball screw, crank or cam coupled to an electric motor, and causes shift fork 33 to move linearly in response to application of electric power. Alternatively, instead of such a mechanism, an electric motor such as a linear motor that directly produces 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 advances or retreats in the axial direction according to the power supply.

According to the combination of the clutch 9 and the actuator 11 described above, it is possible to realize both the intermittent power transmission and the parking lock only by the forward and backward movements of the single cylinder 19 . This enables simplification of the structure of the power transmission device 1 . In addition, since it is not necessary to prepare a control device for the clutch and a control device for the parking lock independently, it is possible to simplify the electrical components for their control. Furthermore, since the cylinder 19 can be driven at any time by using the electric power stored in the battery 17, the clutch 9 can be driven even if the vehicle is stopped or the combustion engine 7 is stalled. Further, the clutch 9 maintains its state even when the power is cut off, so that the parking lock is not released unintentionally.

The actuator 11 need not be driven only by the operation of the cylinder 19, and may be returned to a specific position using an elastic body such as a coil spring or leaf spring. For example, if an elastic body is arranged to urge the shift fork 33 toward the neutral position, the clutch 9 automatically returns to the state shown in FIG. 4(a) when the power is turned off. Alternatively, if an elastic body is arranged to return to the state shown in FIG.

A ring gear 41 is fitted to the shaft 23 so as 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 . Also splined to shaft 23 is a pinion 43 that meshes with ring gear 48 of differential 47 , which may be positioned axially adjacent ring gear 41 . The pinion 43 meshes with a ring gear 48 of a differential 47 or with a first gear set 45 .

The shaft 23 can be hollow, for example for weight reduction purposes. One or more through holes may extend radially from the cavity toward the bearing so that the cavity may be used to supply lubricating oil to the bearing. The lubricating oil is supplied to the bearings using the centrifugal force of the shaft 23 .

The power transmission device 1 includes a first drive shaft 51 drivingly coupled to the electric motor 3 , one end of which faces the outside of the casing 21 . Such one end may include splines for coupling. First drive shaft 51 also includes pinion 52 , either integrally or separately, drivingly coupled to ring gear 48 provided by differential 47 . Intermediate shaft 55 with ring gear 56 and pinion 50 may be interposed therebetween. These mutually meshing gears constitute a first gear set 45 . These gears may be helical gears, or may be of other types such as spur gears.

In order to operate the electric motor 3 in a higher rotation range, the first gear set 45 can be a reduction gear. A first gear set 45 rotates a differential 47 via a 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 pulled out of the casing 21 and coupled to the combustion engine 7 . Such one end may include splines for coupling. Other devices such as dry clutches and torque dampers may be interposed between combustion engine 7 and shaft 57 .

The generator 5 is coupled directly to the second drive shaft 57 or to a separate driven shaft 59 . Driven shaft 59 may also have a spline at one end thereof. The drive shaft 57 is provided with a ring gear 58 integrally or separately, and the driven shaft 59 is provided with a pinion 60 meshing therewith to form the second gear set 49 . Helical gears or other types can be applied to these gears as well.

In order to operate the generator 5 in a higher speed 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 an increasing speed gear.

All these shafts can be parallel to each other and each gear can be arranged about a plane perpendicular to the shafts. Therefore, the entire power transmission device 1 can be made extremely small in the width direction. Also, it is not necessary to arrange these shafts in a single horizontal plane, for example placing the first drive shaft 51 and the second drive shaft 57 higher and the shaft 23 of the differential 47 and clutch 9 lower. be able to. As a result, the shafts 51 and 57 are brought closer together, so that the entire power transmission device 1 can be made smaller both in the longitudinal direction and in the vertical direction.

According to the above-described embodiment, a large oil pump is not required for operating the clutch, nor is an oil path for introducing the hydraulic pressure into the clutch, so the power transmission device 1 is simple and compact. Yes, especially around the clutch can be made compact. This significantly increases the design freedom on the part of the vehicle.

Further, according to the power transmission device 1 described above, from the state shown in FIG. 4A in which only the first power source (eg, electric motor) drives the vehicle, the second power source (eg, combustion engine and generator) The state shown in FIG. 4(b), in which the actuator 11 participates in the drive, can be shifted to the state shown in FIG. 4(b) simply by driving the actuator 11 in the axial direction. It is also possible to transition to a state. These three states can be achieved by only one actuator, and there is no need to prepare a separate parking lock mechanism, so the device can be made simple and compact. In addition, since it is sufficient to control only one actuator, electrical components for control can be simplified, so that the power transmission device can be made simpler and more compact.

Although several embodiments have been described, modifications and variations of the embodiments are possible based on the above disclosure.

Provided is a power transmission device that is simple and compact, yet can realize both the intermittent operation of a power source and the parking lock.

1 power transmission device 3 electric motor 5 generator 7 combustion engine 9 clutch 11 actuator 13 gearbox 15 electric control unit (ECU)
17 Battery 19 Electric Cylinder 21 Casing 23 Shaft 25 Hub 27 Coupling Sleeve 29 Cone 29a Tooth 31 Parking Gear 31a Tooth 33 Shift Fork 35 Synchronizer Ring 41 Ring Gear 43 Pinion 45 First Gear Group 47 Differential 48 Ring Gear 49 Second Gear Group 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 power source to an axle,
a differential that differentially distributes the torque to the axles;
a first set of gears drivingly coupled to the differential;
a second set of gears drivingly coupled to the power source;
a fixed parking gear;
a first state in which the first gear set is freed from the second gear set; a second state in which the first gear set is connected to the second gear set; and the first gear. a clutch configured to selectively achieve a third state that couples the set to the parking gear;
An axially movable shift fork that achieves the first state at a first position and achieves the second state at a second position axially moved from the first position. a shift fork coupled to said clutch to achieve said third state at a third position opposite said second position with respect to said first position;
A power transmission device with a further comprising an actuator with an axially movable shift fork,
The first state is realized when the shift fork is at the first position, the second state is realized at the second position where the shift fork is axially moved from the first position, and the shift fork is at the first position. 2. The power transmission device of claim 1, wherein said shift fork and said clutch are coupled to achieve said third condition at a third position opposite to said second position. The clutch has a hub drivingly connected to the first set of gears, teeth drivingly connected to the second set of gears, and is splined to the hub and axially movable, 3. The power transmission of claim 2, comprising a coupling sleeve engageable with one of said teeth and said parking gear by moving in a direction. further comprising a casing enclosing a single space and dimensioned to house said first and second gear sets, said differential and said clutch in said space;
The actuator includes a cylinder arranged outside the casing, and the shift fork extends from the cylinder, penetrates the casing, and is coupled to the coupling sleeve.
4. A power transmission device according to claim 3. 5. The clutch further comprises a synchronizer interposed between the teeth and the hub for synchronizing the teeth with the hub, and no synchronizer is interposed between the parking gear and the hub. power transmission device.

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