Power transmission mechanism

Abstract

To reduce a load on a bearing member in a power transmission mechanism of a vehicle.SOLUTION: A power transmission mechanism 5 comprises: a first rotating shaft 51 to be rotated and driven by a travel motor 3; a first speed change mechanism T1 for decelerating rotation of the first rotating shaft 51, and transmitting it to a second rotating shaft 52; and a second speed change mechanism T2 for decelerating rotation of the second rotating shaft 52, and transmitting it to a third rotating shaft 53 connected to a drive wheel 6 of a vehicle V. The first speed change mechanism T1 comprises a first gear 11 fixed to the first rotating shaft 51; a second gear 12 supported via a bearing member B1 by the second rotating shaft 52 so as to be relatively rotatable with the second rotating shaft 52, and transmitting power with the first gear 11; and a first clutch C1 for regulating or allowing relative rotation of the second gear 12 and the second rotating shaft 52.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power transmission mechanism.

Background Art

[0002] Patent Document 1 discloses an electric vehicle including an internal combustion engine, a power generation motor disposed to be able to generate power by receiving the power of the internal combustion engine, and a traveling motor disposed to be able to be driven by the power generated by the power generation motor.

[0003] In the electric vehicle described in Patent Document 1, there are a series hybrid mode in which the power generation motor is driven by the power of the internal combustion engine and the traveling motor is operated by the power generated by the power generation motor, and a direct engine connection mode in which the power of the internal combustion engine and the power of the power generation motor are transmitted to the drive wheels to travel, which are configured to be switchable.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The electric vehicle described in Patent Document 1 is configured to decelerate the rotation of the traveling motor by a two-stage speed change mechanism and transmit it to the drive wheels. Further, in the electric vehicle described in Patent Document 1, when traveling in the direct engine connection mode, the clutch is released to cut off the power transmission between the traveling motor and the drive wheels.

[0006] When the vehicle is running in direct-drive mode, the rotation of the drive wheels is accelerated by a two-stage transmission mechanism and transmitted to the drive motor. At this time, the clutch is disengaged and the drive motor's rotating shaft is stopped, so the difference in rotational speed between the drive motor's rotating shaft and the gear of the transmission mechanism that is spinning freely relative to the drive motor's rotating shaft becomes large. When the difference in rotational speed between the drive motor's rotating shaft and the gear of the transmission mechanism that is spinning freely relative to the drive motor's rotating shaft becomes large, the load on the bearing member provided between the drive motor's rotating shaft and this gear becomes large.

[0007] The objective of this invention is to reduce the load on bearing members in a vehicle's power transmission mechanism. [Means for solving the problem]

[0008] According to one aspect of the present invention, the power transmission mechanism includes a first rotating shaft that is rotationally driven by a motor, a first transmission mechanism that reduces the rotation of the first rotating shaft and transmits it to a second rotating shaft, and a second transmission mechanism that reduces the rotation of the second rotating shaft and transmits it to a third rotating shaft connected to the drive wheels of a vehicle. The first transmission mechanism includes a first gear fixed to the first rotating shaft, a second gear supported on the second rotating shaft via a bearing member so as to be rotatable relative to the second rotating shaft and transmitting power to the first gear, and a first clutch that restricts or allows relative rotation between the second gear and the second rotating shaft. The power transmission mechanism further comprises a fourth rotating shaft driven by an engine, and a third speed transmission mechanism that reduces the rotation of the fourth rotating shaft and transmits it to the second rotating shaft. The first rotating shaft and the fourth rotating shaft are provided coaxially, the second rotating shaft is provided below the plane passing through the axes of the first and third rotating shafts, and the third rotating shaft is provided below the first rotating shaft. [Effects of the Invention]

[0009] According to the above embodiment, the load on the bearing members in the vehicle's power transmission mechanism can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram of the drive system of a vehicle according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram of the power transmission mechanism of a vehicle according to an embodiment of the present invention. [Figure 3]Figure 3 is an external front view of a vehicle power transmission mechanism according to an embodiment of the present invention. [Figure 4] Figure 4 is a schematic diagram of the power transmission mechanism of a vehicle in a comparative example. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the attached drawings.

[0012] Figure 1 is a schematic diagram of the drive system S of a vehicle V according to an embodiment of the present invention.

[0013] As shown in Figure 1, the drive system S according to this embodiment is mounted on a vehicle V and constitutes the propulsion system of the vehicle V. The drive system S comprises an engine 1, an electric motor for power generation (hereinafter referred to as "power generation motor") 2, an electric motor for driving (hereinafter referred to as "driving motor") 3, a battery 4, a power transmission mechanism 5, and a controller 9.

[0014] Engine 1 is, for example, an internal combustion engine that uses gasoline as fuel. The crankshaft 1a of engine 1 is connected to the rotating shaft 2a of the generator motor 2 via a transmission mechanism 7 consisting of multiple gears. The torque of engine 1 is transmitted to the generator motor 2 through the transmission mechanism 7 at a predetermined gear ratio, and operates the generator motor 2.

[0015] The generator motor 2 is configured, for example, as a three-phase AC permanent magnet synchronous motor. When the generator motor 2 receives rotational power from the engine 1, it functions as a generator. Furthermore, when the generator motor 2 receives power from the battery 4, it can function as a starter motor for the engine 1 or as a motoring motor to rotate the engine 1.

[0016] The electric power generated by the power generation motor 2 is charged into the battery 4. Also, the electric power generated by the power generation motor 2 can be directly supplied to the driving motor 3. The power generation by the power generation motor 2 is controlled according to the charge state of the battery 4, the driving state of the vehicle V, etc.

[0017] The driving motor 3 is constituted by, for example, a three-phase AC permanent magnet synchronous motor. The driving motor 3 is driven by the electric power supplied from the battery 4 via an inverter (not shown). The rotational power by the driving motor 3 is transmitted to the drive wheels 6 via a plurality of speed change mechanisms described later. Also, the driving motor 3 has a regeneration function of generating the electric power for charging the battery 4 by receiving the rotational power from the drive wheels 6 when the vehicle V decelerates or brakes.

[0018] The battery 4 is constituted by, for example, a lithium ion battery. The battery 4 is charged with the electric power generated by the power generation motor 2 and the electric power regenerated by the driving motor 3, and supplies the charged electric power to the power generation motor 2 and the driving motor 3.

[0019] The SOC (state of charge) of the battery 4 is detected by an SOC sensor (not shown) and transmitted to the controller 9. The controller 9 performs charge control of the battery 4 based on the SOC (state of charge). When the SOC of the battery 4 drops to the lower limit value of the charge control, the controller 9 drives the engine 1. Thereby, the power generation motor 2 is driven, the electric power generated by the power generation motor 2 is supplied to the battery 4, and the battery 4 is charged. On the contrary, when the SOC of the battery 4 rises to the upper limit value of the charge control, the controller 9 stops the engine 1. Thereby, the power generation motor 2 stops, and the power generation by the power generation motor 2 stops.

[0020] The controller 9 controls the operations of the engine 1, the power generation motor 2, the driving motor 3, and the power transmission mechanism 5. The controller 9 is constituted by, for example, a microcomputer including a central processing unit (CPU), various storage units such as a ROM and a RAM, an input / output interface, etc.

[0021] Various parameter information indicating the driving state of the vehicle V is input to the controller 9. Specifically, signals indicating the operation amount of the accelerator pedal by the driver, signals indicating the traveling speed of the vehicle V, signals indicating the rotational speed of the engine 1, signals indicating the rotational speed of the power generation motor 2, signals indicating the rotational speed of the traveling motor 3, signals indicating the SOC of the battery 4, etc. are input to the controller 9.

[0022] Based on the various input signals, the controller 9 executes a predetermined calculation to control the operations of the engine 1, the power generation motor 2, the traveling motor 3, and the power transmission mechanism 5.

[0023] Next, referring to FIGS. 1 to 3, the specific configuration of the power transmission mechanism 5 will be described.

[0024] The power transmission mechanism 5 decelerates the rotational power of the engine 1 and the traveling motor 3 and transmits it to the drive wheels 6. The power transmission mechanism 5 includes a first rotating shaft 51 connected to the rotating shaft 3a of the traveling motor 3 and rotating integrally with the rotating shaft 3a of the traveling motor 3, a second rotating shaft 52 to which the rotation of the first rotating shaft 51 is transmitted, a third rotating shaft 53 that performs power transmission with the drive wheels 6 via a drive shaft and a differential mechanism 8, a fourth rotating shaft 54 that is rotationally driven by the engine 1, a first speed change mechanism T1 that decelerates the rotation of the first rotating shaft 51 and transmits it to the second rotating shaft 52, a second speed change mechanism T2 that decelerates the rotation of the second rotating shaft 52 and transmits it to the third rotating shaft 53, and a third speed change mechanism T3 that decelerates the rotation of the fourth rotating shaft 54 and transmits it to the second rotating shaft 52. The axis center of the first rotating shaft 51 and the axis center of the fourth rotating shaft 54 are arranged to be the same.

[0025] As shown in FIG. 2, the first speed change mechanism T1 includes a first gear 11 fixed to the first rotating shaft 51, a second gear 12 that is supported by the second rotating shaft 52 via a bearing member B1 so as to be relatively rotatable with respect to the second rotating shaft 52 and performs power transmission with the first gear 11, and a first clutch C1 that regulates or permits the relative rotation between the second gear 12 and the second rotating shaft 52. As the bearing member B1, for example, a roller bearing is used.

[0026] The number of teeth on the first gear 11 is set to be fewer than the number of teeth on the second gear 12. As a result, the rotation of the travel motor 3 (first rotating shaft 51) is reduced and transmitted to the second rotating shaft 52. Conversely, the rotation of the second rotating shaft 52 is increased in speed and transmitted to the travel motor 3 (first rotating shaft 51).

[0027] The first clutch C1 is composed of, for example, a sleeve 10 that moves axially along the outer circumferential surface of the second rotating shaft 52, a hub 10a fixed to the second rotating shaft 52, and a clutch gear 12a provided on the second gear 12. The sleeve 10 rotates integrally with the second rotating shaft 52 via the hub 10a and is supported by the hub 10a so as to be movable in the axial direction of the second rotating shaft 52. The movement of the sleeve 10 is controlled by an actuator (not shown). When the sleeve 10 engages with the clutch gear 12a provided on the second gear 12, the relative rotation between the second gear 12 and the second rotating shaft 52 is restricted, and the second gear 12 and the second rotating shaft 52 rotate as a single unit. This enables power transmission between the first rotating shaft 51 and the second rotating shaft 52 by the first transmission mechanism T1. In contrast, when the engagement between the sleeve 10 and the clutch gear 12a is released, the second gear 12 becomes capable of relative rotation with respect to the second rotating shaft 52; in other words, the second gear 12 spins freely relative to the second rotating shaft 52. This interrupts the power transmission between the first rotating shaft 51 and the second rotating shaft 52 by the first transmission mechanism T1.

[0028] The second transmission mechanism T2 includes a third gear 21 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52, a fourth gear 22 fixed to the third rotating shaft 53 and transmitting power to the third gear 21, a fifth gear 23 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52, a sixth gear 24 fixed to the third rotating shaft 53 and transmitting power to the fifth gear 23, and a second clutch C2 that restricts or allows the relative rotation between the third gear 21 and the second rotating shaft 52, and the relative rotation between the fifth gear 23 and the second rotating shaft 52.

[0029] The third gear 21 has fewer teeth than the fourth gear 22. As a result, in power transmission via the third gear 21 and the fourth gear 22, the rotation of the second rotating shaft 52 is reduced in speed and transmitted to the third rotating shaft 53. Conversely, the rotation of the third rotating shaft 53 is accelerated and transmitted to the second rotating shaft 52.

[0030] The fifth gear 23 has fewer teeth than the sixth gear 24. As a result, in power transmission via the fifth gear 23 and the sixth gear 24, the rotation of the second rotating shaft 52 is reduced and transmitted to the third rotating shaft 53. Conversely, the rotation of the third rotating shaft 53 is accelerated and transmitted to the second rotating shaft 52. In this embodiment, the gear ratio between the fifth gear 23 and the sixth gear 24 is set to be smaller than the gear ratio between the third gear 21 and the fourth gear 22.

[0031] The second transmission mechanism T2 allows for two-stage gear changes by switching the second clutch C2: a high-speed gear consisting of the third gear 21 and the fourth gear 22, and a low-speed gear consisting of the fifth gear 23 and the sixth gear 24.

[0032] The second clutch C2 is composed of, for example, a sleeve 20 that moves axially along the outer circumferential surface of the second rotating shaft 52, a hub 20a fixed to the second rotating shaft 52, a clutch gear 21a provided on the third gear 21, and a clutch gear 23a provided on the fifth gear 23. The sleeve 20 rotates integrally with the second rotating shaft 52 via the hub 20a and is supported by the hub 20a so as to be movable in the axial direction of the second rotating shaft 52. The movement of the sleeve 20 is controlled by an actuator (not shown). When the sleeve 20 engages with the clutch gear 21a provided on the third gear 21, the relative rotation between the third gear 21 and the second rotating shaft 52 is restricted, and the third gear 21 and the second rotating shaft 52 rotate as a single unit. This enables power transmission between the second rotating shaft 52 and the third rotating shaft 53 through the power transmission path via the third gear 21 and the fourth gear 22 in the second transmission mechanism T2. In contrast, when the engagement between the sleeve 20 and the clutch gear 21a provided on the third gear 21 is released, the third gear 21 becomes capable of relative rotation with respect to the second rotating shaft 52; in other words, the third gear 21 spins freely relative to the second rotating shaft 52. This interrupts the power transmission between the second rotating shaft 52 and the third rotating shaft 53 through the power transmission path via the third gear 21 and the fourth gear 22 in the second transmission mechanism T2.

[0033] Furthermore, when the sleeve 20 engages with the clutch gear 23a provided on the fifth gear 23, the relative rotation between the fifth gear 23 and the second rotating shaft 52 is restricted, causing the fifth gear 23 and the second rotating shaft 52 to rotate as a single unit. This enables power transmission between the second rotating shaft 52 and the third rotating shaft 53 through the power transmission path via the fifth gear 23 and the sixth gear 24 in the second transmission mechanism T2. Conversely, when the engagement between the sleeve 20 and the clutch gear 23a provided on the fifth gear 23 is released, the fifth gear 23 becomes capable of relative rotation with respect to the second rotating shaft 52; in other words, the fifth gear 23 spins freely relative to the second rotating shaft 52. This interrupts power transmission between the second rotating shaft 52 and the third rotating shaft 53 through the power transmission path via the fifth gear 23 and the sixth gear 24 in the second transmission mechanism T2.

[0034] The third transmission mechanism T3 includes a seventh gear 31 fixed to the fourth rotating shaft 54, an eighth gear 32 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52 and transmitting power to the seventh gear 31, a ninth gear 33 fixed to the fourth rotating shaft 54, a tenth gear 34 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52 and transmitting power to the ninth gear 33, and a third clutch C3 that restricts or allows the relative rotation between the eighth gear 32 and the second rotating shaft 52, and between the tenth gear 34 and the second rotating shaft 52.

[0035] The number of teeth on the seventh gear 31 is less than the number of teeth on the eighth gear 32. As a result, in power transmission via the seventh gear 31 and the eighth gear 32, the rotation of the fourth rotating shaft 54 ​​is reduced in speed and transmitted to the second rotating shaft 52. Conversely, the rotation of the second rotating shaft 52 is increased in speed and transmitted to the fourth rotating shaft 54.

[0036] The number of teeth on the ninth gear 33 is less than the number of teeth on the tenth gear 34. As a result, in power transmission via the ninth gear 33 and the tenth gear 34, the rotation of the fourth rotating shaft 54 ​​is reduced and transmitted to the second rotating shaft 52. Conversely, the rotation of the second rotating shaft 52 is reduced and transmitted to the fourth rotating shaft 54. In this embodiment, the gear ratio between the ninth gear 33 and the tenth gear 34 is set to be smaller than the gear ratio between the seventh gear 31 and the eighth gear 32.

[0037] The third transmission mechanism T3 allows for two-stage gear changes by switching the third clutch C3: a low-speed gear consisting of the seventh gear 31 and the eighth gear 32, and a high-speed gear consisting of the ninth gear 33 and the tenth gear 34.

[0038] The third clutch C3 is composed of, for example, a sleeve 30 that moves axially along the outer circumferential surface of the second rotating shaft 52, a hub 30a fixed to the second rotating shaft 52, a clutch gear 32a provided on the eighth gear 32, and a clutch gear 34a provided on the tenth gear 34. The sleeve 30 rotates integrally with the second rotating shaft 52 via the hub 30a and is supported by the hub 30a so as to be movable in the axial direction of the second rotating shaft 52. The movement of the sleeve 30 is controlled by an actuator (not shown). When the sleeve 30 engages with the clutch gear 32a provided on the eighth gear 32, the relative rotation between the eighth gear 32 and the second rotating shaft 52 is restricted, and the eighth gear 32 and the second rotating shaft 52 rotate as a single unit. This enables power transmission between the fourth rotating shaft 54 ​​and the second rotating shaft 52 through the power transmission path via the seventh gear 31 and the eighth gear 32 in the third transmission mechanism T3. In contrast, when the engagement between the sleeve 30 and the clutch gear 32a provided on the eighth gear 32 is released, the eighth gear 32 becomes capable of relative rotation with respect to the second rotating shaft 52; in other words, the eighth gear 32 spins freely relative to the second rotating shaft 52. This interrupts the power transmission between the fourth rotating shaft 54 ​​and the second rotating shaft 52 through the power transmission path via the seventh gear 31 and the eighth gear 32 in the third transmission mechanism T3.

[0039] Furthermore, when the sleeve 30 engages with the clutch gear 34a provided on the tenth gear 34, the relative rotation between the tenth gear 34 and the second rotating shaft 52 is restricted, causing the tenth gear 34 and the second rotating shaft 52 to rotate as a single unit. This enables power transmission between the fourth rotating shaft 54 ​​and the second rotating shaft 52 through the power transmission path via the ninth gear 33 and the tenth gear 34 in the third transmission mechanism T3. Conversely, when the engagement between the sleeve 30 and the clutch gear 34a provided on the tenth gear 34 is released, the tenth gear 34 becomes capable of relative rotation with respect to the second rotating shaft 52; in other words, the tenth gear 34 spins freely relative to the second rotating shaft 52. This interrupts power transmission between the fourth rotating shaft 54 ​​and the second rotating shaft 52 through the power transmission path via the ninth gear 33 and the tenth gear 34 in the third transmission mechanism T3.

[0040] In this embodiment, as shown in Figure 3, the third rotation shaft 53 is provided below the first rotation shaft 51, and the second rotation shaft 52 is provided below the plane P that passes through the axes of the first rotation shaft 51 and the third rotation shaft 53. With this configuration, a space A can be secured between the first rotation shaft 51 and the third rotation shaft 53 for installing actuators that control the sleeves 10, 20, and 30 provided on the second rotation shaft 52. As a result, the actuators can be provided as far below the vehicle V as possible, thereby preventing the passenger compartment from becoming narrower.

[0041] In this configuration, vehicle V can switch between two driving modes: series hybrid mode and direct engine drive mode. In series hybrid mode, vehicle V is driven by the power of the drive motor 3. In direct engine drive mode, vehicle V is basically driven by the power of engine 1.

[0042] In series hybrid mode, the first clutch C1 and the second clutch C2 are engaged, and the third clutch C3 is released. Specifically, the first clutch C1 is engaged with the second gear 12, and the second clutch C2 is engaged with either the third gear 21 or the fifth gear 23. This allows the torque of the drive motor 3 to be transmitted to the drive wheels 6 through the first transmission mechanism T1, the second transmission mechanism T2, and the drive shaft. At the same time, the engagement of the third clutch C3 with the eighth gear 32 and the tenth gear 34 is released. This interrupts the power transmission between the fourth rotating shaft 54 ​​and the second rotating shaft 52 through the third transmission mechanism T3. In other words, the torque of the engine 1 is prevented from being transmitted to the drive motor 3 and the drive wheels 6 through the third transmission mechanism T3.

[0043] In series hybrid mode, by controlling the first clutch C1, second clutch C2, and third clutch C3 in this manner, the vehicle V drives the drive wheels 6 solely by the torque of the drive motor 3. In series hybrid mode, the engine 1 is driven as needed to generate electricity with the generator motor 2. At this time, power transmission between the engine 1 and the drive wheels 6 is interrupted by the third transmission mechanism T3, so the torque of the engine 1 is not transmitted to the drive wheels 6. The drive motor 3 functions as a generator when the rotational power of the drive wheels 6 is transmitted through the drive shaft, the second transmission mechanism T2, and the first transmission mechanism T1. The electricity generated by the drive motor 3 is supplied to the battery 4 and used to charge the battery 4.

[0044] In engine direct-drive mode, the first clutch C1 is released, and the second clutch C2 and third clutch C3 are engaged. Specifically, the third clutch C3 is engaged with either the eighth gear 32 or the tenth gear 34, and the second clutch C2 is engaged with either the fourth gear 22 or the sixth gear 24. This allows the torque of the engine 1 to be transmitted to the drive wheels 6 through the third transmission mechanism T3, the second transmission mechanism T2, and the drive shaft. At the same time, the engagement between the first clutch C1 and the second gear 12 is released. This interrupts the power transmission between the first rotating shaft 51 and the second rotating shaft 52 through the first transmission mechanism T1. In other words, the torque of the drive motor 3 is prevented from being transmitted to the engine 1 and the drive wheels 6 through the first transmission mechanism T1.

[0045] In engine direct drive mode, by controlling the first clutch C1, second clutch C2, and third clutch C3 in this manner, the vehicle V drives the drive wheels 6 solely by the torque of the engine 1. In addition, in engine direct drive mode, power generation can be performed by the generator motor 2 as needed. If the generator motor 2 is configured as a motor generator, it is also possible to transmit the torque of the generator motor 2, as well as the engine 1, to the drive wheels 6 through the third transmission mechanism T3, the second transmission mechanism T2, and the drive shaft.

[0046] The switching between series hybrid mode and direct engine drive mode in the power transmission mechanism 5 is controlled by the controller 9. The controller 9 switches the engagement and disengagement states of the first clutch C1, the second clutch C2, and the third clutch C3 by controlling actuators (not shown) that drive sleeves 10, 20, and 30 according to the driving mode.

[0047] Incidentally, for example, when vehicle V is running in engine direct-drive mode, the first clutch C1 is released as described above. Therefore, the second gear 12 rotates freely relative to the second rotating shaft 52. At this time, the bearing member B1 absorbs the difference in rotational speed between the second gear 12 and the second rotating shaft 52. Now, the operation of the power transmission mechanism 5 of the present invention will be explained with reference to the comparative example shown in Figure 4.

[0048] First, the configuration of the comparative example shown in Figure 4 will be described. In the power transmission mechanism 105 of the comparative example shown in Figure 4, the first transmission mechanism T11 and the third transmission mechanism T31 differ from the first transmission mechanism T1 and the third transmission mechanism T3 of the embodiment shown in Figures 1 and 2. Specifically, in the first transmission mechanism T1 of the embodiment, the first clutch C1 is provided on the second rotating shaft 52, whereas in the first transmission mechanism T11 of the comparative example, the first clutch C11 is provided on the first rotating shaft 51. Also, in the third transmission mechanism T3 of the embodiment, the third clutch C3 is provided on the second rotating shaft 52, whereas in the third transmission mechanism T31 of the comparative example, the third clutch C31 is provided on the fourth rotating shaft 54. Note that in the power transmission mechanism 105 of the comparative example shown in Figure 4, the same numbers are used for components that are identical to those in the power transmission mechanism 5 of the above embodiment.

[0049] The first transmission mechanism T11 includes a first gear 111 supported on a first rotating shaft 51 via a bearing member B1 so as to be rotatable relative to the first rotating shaft 51, a second gear 112 fixed to a second rotating shaft 52 and transmitting power to the first gear 111, and a first clutch C11 that restricts or allows relative rotation between the first gear 111 and the first rotating shaft 51.

[0050] The first gear 111 has fewer teeth than the second gear 112. As a result, the rotation of the travel motor 3 (first rotating shaft 51) is reduced in speed and transmitted to the second rotating shaft 52. Conversely, the rotation of the second rotating shaft 52 is increased in speed and transmitted to the travel motor 3 (first rotating shaft 51).

[0051] The configuration and operation of the first clutch C11 are the same as those of the first clutch C1, so a detailed explanation will be omitted.

[0052] The third transmission mechanism T31 includes a seventh gear 131 supported on the fourth rotating shaft 54 ​​via a bearing member B1 so as to be rotatable relative to the fourth rotating shaft 54, an eighth gear 132 fixed to the second rotating shaft 52 and transmitting power to the seventh gear 131, a ninth gear 133 supported on the fourth rotating shaft 54 ​​via a bearing member B1 so as to be rotatable relative to the fourth rotating shaft 54, a tenth gear 134 fixed to the second rotating shaft 52 and transmitting power to the ninth gear 133, and a third clutch C31 that restricts or allows the relative rotation between the seventh gear 131 and the fourth rotating shaft 54, and the relative rotation between the ninth gear 133 and the fourth rotating shaft 54.

[0053] The number of teeth on the seventh gear 131 is less than the number of teeth on the eighth gear 132. As a result, in power transmission via the seventh gear 131 and the eighth gear 132, the rotation of the fourth rotating shaft 54 ​​is reduced in speed and transmitted to the second rotating shaft 52. Conversely, the rotation of the second rotating shaft 52 is increased in speed and transmitted to the fourth rotating shaft 54.

[0054] The ninth gear 133 has fewer teeth than the tenth gear 134. As a result, in power transmission via the ninth gear 133 and the tenth gear 134, the rotation of the fourth rotating shaft 54 ​​is reduced and transmitted to the second rotating shaft 52. Conversely, the rotation of the second rotating shaft 52 is reduced and transmitted to the fourth rotating shaft 54.

[0055] The configuration and operation of the third clutch C31 are the same as those of the third clutch C3, so a detailed explanation will be omitted.

[0056] In the comparative example shown in Figure 4, which is configured in this way, for example, when the vehicle V is moving (the drive wheels 6 are rotating) in the direct-drive engine mode, the rotation of the third rotating shaft 53 connected to the drive wheels 6 is accelerated by the second transmission mechanism T2 and transmitted to the second rotating shaft 52. The rotation of the second rotating shaft 52 is further accelerated by the first transmission mechanism T11 and transmitted to the first gear 111.

[0057] In engine direct-drive mode, the first clutch C11 is released, so the first gear 111 rotates freely relative to the stationary first rotating shaft 51. At this time, the difference in rotational speed between the first rotating shaft 51 and the first gear 111 is equal to the difference in rotational speed resulting from the two-stage speed increase of the third rotating shaft 53 by the second transmission mechanism T2 and the first transmission mechanism T11. As a result, the bearing member B1 provided between the first rotating shaft 51 and the first gear 111 is subjected to a large load because it is affected by the rotational speed difference resulting from the two-stage speed increase of the third rotating shaft 53 by the second transmission mechanism T2 and the first transmission mechanism T11.

[0058] In contrast, in the power transmission mechanism 5 of this embodiment, when the drive wheel 6 is rotating, the rotation of the third rotating shaft 53 connected to the drive wheel 6 is accelerated by the second transmission mechanism T2 and transmitted to the second rotating shaft 52. However, since the first clutch C1 is released, the rotation of the second rotating shaft 52 is not transmitted to the first rotating shaft 51.

[0059] In engine direct drive mode, the drive motor 3 is stopped, so the second gear 12 is also stopped. Furthermore, since the first clutch C1 is released, the second gear 12 rotates relative to the rotating second rotating shaft 52 (freewheeling). At this time, the difference in rotational speed between the second rotating shaft 52 and the second gear 12 is equal to the difference in rotational speed of the third rotating shaft 53 increased by the second transmission mechanism T2. In other words, according to the power transmission mechanism 5 of this embodiment, the difference in rotational speed between the rotating shaft and the freewheeling gear can be reduced by the amount of speed increase by the first transmission mechanism T1 compared to the comparative example shown in Figure 4. As a result, the load on the bearing member B1 can be reduced, and thus the lifespan of the bearing member B1 can be improved.

[0060] Furthermore, in the comparative example shown in Figure 4, when the vehicle V is moving in series hybrid mode (the drive wheels 6 are rotating), the rotation of the third rotating shaft 53 connected to the drive wheels 6 is accelerated by the second transmission mechanism T2 and transmitted to the second rotating shaft 52. The rotation of the second rotating shaft 52 is further accelerated by the third transmission mechanism T31 and transmitted to the seventh gear 131 and the ninth gear 133.

[0061] In series hybrid mode, the fourth rotating shaft 54 ​​rotates because engine 1 is driven to generate electricity, but the third clutch C31 is disengaged, so the seventh gear 131 and the ninth gear 133 rotate relative to the fourth rotating shaft 54 ​​(freewheeling). As a result, the difference in rotational speed between the fourth rotating shaft 54 ​​and the seventh and ninth gears 131 and 133 is the difference between the rotational speed of the third rotating shaft 53, which has been accelerated by two stages by the second and third transmission mechanisms T2 and T31, and the rotational speed of the fourth rotating shaft 54. Consequently, the bearing member B1 provided between the fourth rotating shaft 54 ​​and the seventh and ninth gears 131 is subjected to a large load because it is affected by the difference in rotational speed between the rotational speed of the third rotating shaft 53, which has been accelerated by two stages by the second and third transmission mechanisms T31, and the rotational speed of the fourth rotating shaft 54.

[0062] In contrast, in the power transmission mechanism 5 of this embodiment, when the drive wheel 6 is rotating, the rotation of the third rotating shaft 53 connected to the drive wheel 6 is accelerated by the second transmission mechanism T2 and transmitted to the second rotating shaft 52. However, since the third clutch C3 is released, the rotation of the second rotating shaft 52 is not transmitted to the fourth rotating shaft 54.

[0063] Furthermore, in series hybrid mode, the engine 1 is driven to generate electricity, so the fourth rotating shaft 54 ​​is rotating. In the power transmission mechanism 5 of this embodiment, the rotation of the fourth rotating shaft 54 ​​is transmitted to the eighth gear 32 and the tenth gear 34 through the seventh gear 31 and the ninth gear 33, causing the eighth gear 32 and the tenth gear 34 to rotate. At this time, since the third clutch C3 is released, the eighth gear 32 and the tenth gear 34 rotate relative to the second rotating shaft 52 (freewheeling). The difference in rotational speed between the second rotating shaft 52 and the eighth gear 32 and the tenth gear 34 is the difference between the rotational speed of the third rotating shaft 53 increased by the second transmission mechanism T2 and the rotational speed reduced by the fourth transmission mechanism T4. In other words, according to the power transmission mechanism 5 of this embodiment, the difference in rotational speed between the rotating shaft and the freewheeling gear can be reduced by the amount of the speed increase by the third transmission mechanism T3, compared to the comparative example shown in Figure 4. This reduces the load on bearing member B1, thereby improving the lifespan of bearing member B1.

[0064] Thus, according to the power transmission mechanism 5 of this embodiment, the rotational speed difference absorbed by the bearing member B1 provided between the free-spinning gears (second gear 12, eighth gear 32, tenth gear 34) and the second rotating shaft 52 can be reduced, thereby reducing the load acting on the bearing member B1. This improves the lifespan of the bearing member B1.

[0065] Furthermore, in the comparative example power transmission mechanism 105 shown in Figure 4, the first clutch C11, the second clutch C2, and the third clutch C31 are located on different rotating shafts, so it is necessary to secure separate spaces for the actuators that control them. In contrast, in the power transmission mechanism 5 of this embodiment, the first clutch C1, the second clutch C2, and the third clutch C3 are located on the second rotating shaft 52, so the space for installing the actuators can be consolidated.

[0066] In the above embodiment, the second transmission mechanism T2 and the third transmission mechanism T3 were configured to perform two-stage gear shifting, but they may be configured to perform one-stage gear shifting. In this case, it is not necessary to provide either the second clutch C2 or the third clutch C3. Alternatively, one gear train in the second transmission mechanism T2 and the third transmission mechanism T3 may be configured to reduce speed, and the other gear train to increase speed.

[0067] In the above embodiment, only the series hybrid mode and the direct-drive engine mode were described as driving modes for the vehicle V. However, a parallel hybrid mode in which the vehicle is driven by the power of both the engine 1 and the drive motor 3 may also be included.

[0068] Furthermore, although a roller bearing was used as an example of bearing member B in the above embodiment, bearing member B may be a ball bearing or the like.

[0069] The configuration, operation, and effects of the embodiment of the present invention configured as described above will be explained in summary.

[0070] The power transmission mechanism 5 includes a first rotating shaft 51 that is rotationally driven by a travel motor 3, a first transmission mechanism T1 that reduces the rotation of the first rotating shaft 51 and transmits it to a second rotating shaft 52, and a second transmission mechanism T2 that reduces the rotation of the second rotating shaft 52 and transmits it to a third rotating shaft 53 connected to the drive wheels 6 of the vehicle V. The first transmission mechanism T1 includes a first gear 11 fixed to the first rotating shaft 51, a second gear 12 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52 and transmits power to the first gear 11, and a first clutch C1 that restricts or allows relative rotation between the second gear 12 and the second rotating shaft 52.

[0071] In this configuration, when the second gear 12 spins freely relative to the second rotating shaft 52, the rotational speed difference absorbed by the bearing member B1 provided between the second gear 12 and the second rotating shaft 52 can be reduced, thereby reducing the load acting on the bearing member B1. This improves the lifespan of the bearing member B1.

[0072] In the power transmission mechanism 5, the second transmission mechanism T2 includes a third gear 21 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52, a fourth gear 22 fixed to the third rotating shaft 53 and transmitting power to the third gear 21, and a second clutch C2 that restricts or allows relative rotation between the third gear 21 and the second rotating shaft 52.

[0073] In this configuration, the second clutch C2 can interrupt the power transmission between the second rotating shaft 52 and the third rotating shaft 53, thereby preventing unnecessary power transmission between the second rotating shaft 52 and the third rotating shaft 53.

[0074] In the power transmission mechanism 5, the second transmission mechanism T2 further includes a fifth gear 23 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52, and a sixth gear 24 fixed to the third rotating shaft 53 and transmitting power to the fifth gear 23. The second clutch C2 restricts or allows the relative rotation between the fifth gear 23 and the second rotating shaft 52.

[0075] In this configuration, the rotational speed of the second rotating shaft 52 can be changed in two stages using a single second clutch C2.

[0076] The power transmission mechanism 5 further comprises a fourth rotating shaft 54 ​​that is rotationally driven by the engine 1, and a third transmission mechanism T3 that reduces the rotation of the fourth rotating shaft 54 ​​and transmits it to the second rotating shaft 52. The third transmission mechanism T3 has a seventh gear 31 fixed to the fourth rotating shaft 54, an eighth gear 32 that is supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52 and transmits power to the seventh gear 31, and a third clutch C3 that restricts or allows relative rotation between the eighth gear 32 and the second rotating shaft 52.

[0077] In this configuration, by providing the components related to the third clutch C3 in addition to the first clutch C1 on the second rotating shaft 52, the installation locations of the actuators that control the first clutch C1 and the third clutch C3 can be consolidated. Furthermore, since the eighth gear 32, which rotates relative to the second rotating shaft 52, is supported on the second rotating shaft 52, when the rotation from the drive wheel 6 is accelerated by the second transmission mechanism T2 and transmitted to the second rotating shaft 52, the rotational speed difference between the eighth gear 32 and the second rotating shaft 52 can be reduced. This reduces the load on the bearing member B1.

[0078] In the power transmission mechanism 5, the third gear shift mechanism T3 further includes a ninth gear 33 fixed to the fourth rotating shaft 54, and a tenth gear 34 supported on the second rotating shaft 52 via a bearing member B1 so as to be rotatable relative to the second rotating shaft 52, and which transmits power to the ninth gear 33. The third clutch C3 restricts or allows the relative rotation between the tenth gear 34 and the second rotating shaft 52.

[0079] In this configuration, the rotational speed of engine 1 can be changed in two stages using a single third clutch C3.

[0080] In the power transmission mechanism 5, the first rotating shaft 51 and the fourth rotating shaft 54 ​​are provided on the same axis. The second rotating shaft 52 is provided below the plane P that passes through the axes of the first rotating shaft 51 and the third rotating shaft 53.

[0081] In this configuration, space can be secured between the first rotating shaft 51 and the third rotating shaft 53 for installing actuators that control the first clutch C1, the second clutch C2, and the third clutch C3. This allows the actuators to be positioned as low as possible, thus preventing the vehicle interior from becoming cramped.

[0082] In the power transmission mechanism 5, the third rotating shaft 53 is located below the first rotating shaft 51.

[0083] In this configuration, the third rotation axis 53 is positioned at the lowest point, allowing the actuator to be positioned even lower. This helps to minimize the reduction in the size of the passenger compartment.

[0084] It goes without saying that the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the technical idea described in the claims.

[0085] In the above embodiment, the first to third gear shifting mechanisms T1, T2, and T3 were described as having a configuration in which two gears mesh to change speed, but the invention is not limited to this, and a configuration in which three or more gears mesh may also be used. [Explanation of symbols]

[0086] 1...Engine, 2...Generator motor, 3...Driving motor, 4...Battery, 5...Power transmission mechanism, 6...Drive wheels, 9...Controller, 11...First gear, 12...Second gear, 21...Third gear, 22...Fourth gear, 23...Fifth gear, 24...Sixth gear, 31...Seventh gear, 31...Seventh clutch, 32...Eighth gear, 33...Ninth gear, 34...Tenth gear, 51...First rotating shaft, 52...Second rotating shaft, 53...Third rotating shaft, 54...Fourth rotating shaft, T1...First transmission mechanism, B1...Bearing member, C1...First clutch, C2...Second clutch, C3...Third clutch

Claims

1. A first rotating shaft that is driven to rotate by a motor, A first speed change mechanism that reduces the rotation of the first rotating shaft and transmits it to the second rotating shaft, The vehicle comprises a second gearbox that reduces the rotation of the second rotating shaft and transmits it to a third rotating shaft connected to the drive wheels of the vehicle, The first gear shift mechanism is, A first gear fixed to the first rotating shaft, The second gear is supported on the second rotating shaft via a bearing member so as to be rotatable relative to the second rotating shaft, and transmits power to the first gear, It has a first clutch that restricts or allows relative rotation between the second gear and the second rotating shaft, A fourth rotating shaft driven by the engine, The system further comprises a third speed control mechanism that reduces the rotation of the fourth rotating shaft and transmits it to the second rotating shaft, The first rotation axis and the fourth rotation axis are provided on the same axis. The second rotation axis is located below the plane passing through the axes of the first and third rotation axes. The third rotating shaft is a power transmission mechanism located below the first rotating shaft.

2. A power transmission mechanism according to claim 1, The second transmission mechanism is, A third gear is supported on the second rotating shaft via a bearing member so as to be rotatable relative to the second rotating shaft, A fourth gear is fixed to the third rotating shaft and transmits power to the third gear, A power transmission mechanism having a second clutch that restricts or allows relative rotation between the third gear and the second rotating shaft.

3. A power transmission mechanism according to claim 2, The second transmission mechanism is, A fifth gear is supported on the second rotating shaft via a bearing member so as to be rotatable relative to the second rotating shaft, It further comprises a sixth gear fixed to the third rotating shaft and transmitting power to the fifth gear, The second clutch is a power transmission mechanism that restricts or allows relative rotation between the fifth gear and the second rotating shaft.

4. A power transmission mechanism according to any one of claims 1 to 3, The third gear shift mechanism is, A seventh gear fixed to the fourth rotating shaft, An eighth gear is supported on the second rotating shaft via a bearing member so as to be rotatable relative to the second rotating shaft, and transmits power to the seventh gear, A power transmission mechanism having a third clutch that restricts or allows relative rotation between the eighth gear and the second rotating shaft.

5. A power transmission mechanism according to claim 4, The third gear shift mechanism is, The ninth gear fixed to the fourth rotating shaft, The device further comprises a 10th gear which is supported on the second rotating shaft via a bearing member so as to be rotatable relative to the second rotating shaft and transmits power to the 9th gear, The third clutch is a power transmission mechanism that restricts or allows relative rotation between the tenth gear and the second rotating shaft.

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