Mechanical oil pump device
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MITSUBISHI MOTORS CORP
- Filing Date
- 2023-02-15
- Publication Date
- 2026-08-05
AI Technical Summary
【0009】 本発明に係る機械式オイルポンプ装置によれば、車両が前進、後退のどちらに走行する場合にも機械式オイルポンプを駆動して潤滑油を供給することのできる機械式オイルポンプ装置を提供することが可能となる。
Smart Images
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Abstract
Description
Technical Field
[0003]
[0001] The present invention relates to a mechanical oil pump device, and more particularly to a mechanical oil pump device capable of driving a mechanical oil pump to supply lubricating oil regardless of whether the vehicle is moving forward or backward.
Background Art
[0002] Conventionally, in vehicles such as automobiles, there is a type that stores lubricating oil in a housing that houses rotating members to be lubricated, such as gears and clutches that transmit power, in order to lubricate the rotating members. For example, in a 4WD coupling of a four-wheel drive (4WD) vehicle, lubricating oil is stored in a housing that houses a clutch for interrupting power, and the clutch is immersed in the lubricating oil to prevent seizure of the clutch. When lubricating a rotating member with lubricating oil stored in a housing in this way, it is generally known that the drag resistance of the lubricating oil increases, particularly at low temperatures when its viscosity increases, and the fuel efficiency of the vehicle decreases. Also, as a method of suppressing such a decrease in fuel efficiency, it is known to lubricate the rotating member using a mechanical oil pump. An example of a method of lubricating a rotating member using this mechanical oil pump is disclosed in, for example, Patent Document 1. Specifically, a mechanical oil pump device is disclosed that supplies cooling lubricating oil to gears and the like provided in a power transmission mechanism using a mechanical oil pump in a hybrid vehicle equipped with an engine and a motor.
[0003] This conventional mechanical oil pump device is realized by using a power split mechanism, which is a main mechanism of a power train mounted on a hybrid vehicle. The power split mechanism is composed of a conventionally known planetary gear mechanism. That is, it consists of a central sun gear, pinion gears arranged at predetermined intervals in the circumferential direction thereof, a carrier that holds the pinion gears so as to be able to rotate and revolve around the rotation axis of the sun gear, and a ring gear arranged concentrically with the sun gear and meshing with the pinion gears by internal teeth. In a hybrid vehicle, the ring gear of this power split mechanism is connected to the drive wheels via a gear train to transmit torque, while the carrier is connected to the engine's power output shaft. The sun gear is connected to the rotating shaft of a control motor that controls the engine's output, allowing for intermittent torque transmission via a power interruption mechanism. The rotating shaft of the drive motor that outputs power for the hybrid vehicle's movement is connected to the drive wheels and the ring gear via a gear train to transmit torque. In this mechanical oil pump system, the ring gear is further connected to the pump drive shaft for driving the mechanical oil pump via a first one-way clutch that transmits only forward rotation of the ring gear to transmit drive torque. In this mechanical oil pump system, the rotating shaft of the control motor is further connected to the pump drive shaft for driving the mechanical oil pump via a second one-way clutch that transmits only forward rotation of the motor's rotating shaft to transmit drive torque.
[0004] With this configuration, in this mechanical oil pump system, when the vehicle is moving forward, the ring gear, which is powered by the engine or drive motor, rotates in the forward direction. Therefore, the rotation of this ring gear is transmitted as driving torque to the mechanical oil pump via the first one-way clutch. On the other hand, when the vehicle is moving in reverse, the ring gear, which is powered by the drive motor, rotates in the reverse direction (reverse rotation). Therefore, this reverse rotation of the ring gear is interrupted by the first one-way clutch and is not transmitted. However, when the ring gear rotates in reverse in this way, the sun gear rotates in the forward direction as a result of this rotation, and the rotating shaft of the control motor, which is connected to the sun gear via the power interruption mechanism, rotates in the forward direction. As a result, when the vehicle is moving in reverse, the forward rotation of the rotating shaft of this control motor is transmitted as driving torque to the mechanical oil pump via the second one-way clutch. In conventional mechanical oil pump systems, by driving the mechanical oil pump in this way, lubricating oil can be supplied to the gears of the power transmission mechanism, etc., whether the vehicle is moving forward or backward.
[0005] However, this conventional mechanical oil pump system is designed for hybrid vehicles equipped with a control motor to control engine output. Therefore, if such a motor is not present, torque cannot be transmitted to the mechanical oil pump via the second one-way clutch through the rotating shaft of the control motor when the vehicle is reversing. In other words, the conventional mechanical oil pump system could not be applied to vehicles without a control motor. This point is also true for vehicles equipped with a 4WD coupling, where the clutch within the coupling is lubricated using a mechanical oil pump. [Prior art documents] [Patent Documents]
[0006] [Patent Document 1] Japanese Patent Publication No. 2018-103777 [Overview of the project] [Problems that the invention aims to solve]
[0007] The present invention aims to solve the above problems and to provide a mechanical oil pump device that can drive the mechanical oil pump and supply lubricating oil whether the vehicle is moving forward or backward. [Means for solving the problem]
[0008] The mechanical oil pump device according to the present invention comprises a transmission gear for transmitting the rotation of a differential case, which is provided on the outer circumference of a differential case constituting the differential gear of a vehicle along its rotational direction; a first intermediate gear and a second intermediate gear to which the rotation of the differential case is transmitted via the transmission gear; a first drive gear to which the rotation of the differential case is transmitted from the first intermediate gear, which is configured to allow the transmission of the rotation only when the rotation of the differential case is the rotation when the vehicle is moving forward; and a second drive gear to which the rotation of the differential case is transmitted from the second intermediate gear. The system comprises a second drive gear configured to allow transmission of rotation only when the rotation of the differential case is when the vehicle is moving in reverse, and a mechanical oil pump having a pump gear, which is driven by the transmission of the rotation of the differential case to the pump gear to supply lubricating oil to the lubricating object, wherein the pump gear is configured such that when the rotation of the differential case is when the vehicle is moving in forward, the rotation of the differential case is transmitted from the first drive gear, and when the rotation of the differential case is when the vehicle is moving in reverse, the rotation of the differential case is transmitted from the second drive gear. The first intermediate gear is provided so as to mesh with the transmission gear in the rotational direction of the differential case, and is configured to transmit the rotation of the differential case; the first drive gear is provided so as to have the same axis of rotation as the first intermediate gear, and is configured to rotate together with the first intermediate gear when the transmission of rotation is permitted; the second intermediate gear is provided radially to a counter gear for reversing the direction of rotation, which is provided between the first intermediate gear and the first drive gear so as to have the same axis of rotation as the first intermediate gear, and is configured to mesh with the counter gear; the second drive gear is provided so as to have the same axis of rotation as the second intermediate gear, and is configured to rotate together with the second intermediate gear when the transmission of rotation is permitted; and the pump gear is provided radially to the first drive gear and the second drive gear, and is configured to mesh directly with both of these gears. It is characterized by having the following features. [Effects of the Invention]
[0009] The mechanical oil pump device according to the present invention makes it possible to provide a mechanical oil pump device that can drive the mechanical oil pump and supply lubricating oil whether the vehicle is traveling forward or backward. [Brief explanation of the drawing]
[0010] [Figure 1] This is a schematic diagram of a four-wheel drive vehicle to which a mechanical oil pump device according to one embodiment of the present invention is applied. [Figure 2] This diagram shows the configuration of the 4WD coupling device, including the front differential and coupling, which are the drive components for the front wheels. [Figure 3] This is a configuration diagram of a mechanical oil pump device according to one embodiment of the present invention. [Figure 4]This diagram illustrates the operation of a mechanical oil pump device according to one embodiment of the present invention. [Figure 5] This is a diagram illustrating the configuration of a modified mechanical oil pump device. [Figure 6] This diagram illustrates the operation of a modified mechanical oil pump device. [Figure 7] This figure shows the configuration features of a mechanical oil pump device according to one embodiment of the present invention and a modified mechanical oil pump device. [Modes for carrying out the invention]
[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 is a schematic diagram of a four-wheel drive vehicle to which a mechanical oil pump device according to one embodiment of the present invention is applied. As shown in Figure 1, Vehicle 1 is a front-engine, rear-drive (FR) type part-time four-wheel drive (4WD) vehicle based on two-wheel drive (2WD) with rear wheels 82 and 83. In Vehicle 1, four-wheel drive is achieved by transmitting a portion of the driving force from the engine 2 to the front wheels 80 and 81 via the transfer case 4. In other words, in Vehicle 1, the driving force output from the engine 2 is input to the input shaft 11 of the transfer case 4 via the transmission 3, and within the transfer case 4, it is distributed to the front wheels 80 and 81 and the rear wheels 82 and 83 according to the drive mode. The drive mode (vehicle drive method) of the transfer case 4 can be switched to 2WD, 4WD, etc. by the driver operating a rotary-type drive mode selector switch located on the instrument panel in the vehicle's cabin.
[0012] The driving force distributed to the rear wheels 82 and 83 is output from the rear output shaft 12 of the transfer device 4 and input to the rear differential 5 via the rear propeller shaft connected to the rear output shaft 12. This driving force is then equally distributed to the left and right within the rear differential 5 and transmitted to the left and right rear wheels 82 and 83 via the rear axle shafts 15 and 16. On the other hand, the driving force distributed to the front wheels 80 and 81 is transmitted from the drive sprocket 4A of the transfer device 4 to the driven sprocket 13 via the transfer chain 4B. A front propeller shaft 14 extends from the driven sprocket 13 towards the front wheels, and its tip is connected to the front differential 6. Therefore, the driving force transmitted to the driven sprocket 13 is input to the front differential 6 via the front propeller shaft 14, where it is equally distributed to the left and right within the front differential 6 and transmitted to the left and right front wheels 80 and 81 via the front axle shafts 17 and 18.
[0013] Of the front axle shafts 17 and 18, the front axle shaft 18 connected to the right front wheel 81 is equipped with a coupling 7 between the front differential 6 and the front wheel 81. This coupling 7 allows the vehicle 1 to electronically control the driving force distributed to the front wheels and reduces power loss in 2WD mode. Here, the configuration of the front differential 6 and coupling 7, which are the drive system on the front wheels, will be explained with reference to Figure 2. As shown in Figure 2, the front differential (differential gear) 6 is composed of a ring gear 60, a differential case 61, side gears 62 and 63, differential pinions 64 and 65, etc. The ring gear 60, which meshes with the pinion gear 14A at the tip of the front propeller shaft 14, is fixed to the differential case 61 so as to be able to rotate as a whole. In addition, a differential pinion shaft is held in the hollow part of the differential case 61 in a direction perpendicular to the rotation axis of the differential case 61, and a pair of differential pinions 64 and 65 are pivotally supported at both ends of this differential pinion shaft so as to be able to rotate in a direction opposite to each other. A pair of side gears 62 and 63, which are arranged on the left and right sides of the hollow part of the differential case 61 with the differential pinion shaft as the boundary, mesh with these differential pinions 64 and 65. Furthermore, one end of the front axle shafts 17 and 18, which are inserted through the differential case 61, is connected to these side gears 62 and 63 so that they can rotate as a single unit, that is, the end that is not connected to the front wheels 80 and 81. The operation of the front differential 6 is well known, so its explanation will be omitted.
[0014] Next, the coupling 7 is configured to separate the front axle shaft 18 into two parts, with clutches 72 and 73 at each end, and to engage and disengage the clutches 72 and 73 by actuator 71. The engagement and disengagement of these clutches 72 and 73 is performed by arbitrarily adjusting the position of actuator 71 according to instructions from the ECU (not shown). For example, in 4WD mode, the ECU adjusts the position of actuator 71 according to its instructions so that the clutches 72 and 73 are engaged, thereby connecting the right front wheel 81 and the front differential 6 via the front axle shaft 18. Therefore, in 4WD mode, the driving force input from the front propeller shaft 14 to the front differential 6 is distributed equally to the left and right in the front differential 6 and transmitted to the front wheels 80 and 81 via the front axle shafts 17 and 18. On the other hand, in 2WD mode, the ECU adjusts the position of actuator 71 to release the clutch according to its instructions, thereby releasing the engagement of clutches 72 and 73 by actuator 71, and disengaging the right front wheel 81 from the front differential 6. As a result, the side gear 62 on the left front wheel 80 side of the front differential 6 spins freely, and in 2WD mode, the front drivetrain from the front differential 6 to the drive sprocket 4A of the transfer case 4 stops rotating, thus reducing power loss.
[0015] In the vehicle 1, the front differential 6 and the coupling 7 are housed in the same case 9, and lubricating oil for lubricating rotating members to be lubricated such as the ring gear 60 of the front differential 6 is stored (not shown) in the case 9. Also, in the case 9, a mechanical oil pump device 100 is provided to supply the lubricating oil to the clutches 72, 73 of the coupling 7 mainly using a mechanical oil pump to prevent seizure of the clutches. That is, in the vehicle 1, the mechanical oil pump device 100 can suppress a decrease in the fuel consumption of the vehicle 1 while lubricating the clutches of the coupling 7. Thus, in the vehicle 1, the front differential 6, the coupling 7, the mechanical oil pump device 100, and the case 9 are arranged on the front wheel side of the vehicle, and these constitute a 4WD coupling device 90. Further, the mechanical oil pump device 100 is configured such that the rotation of the differential case 61 is transmitted by a transmission gear 66 provided on the differential case 61, thereby driving the mechanical oil pump of the device 100. The transmission gear 66 is provided on the outer periphery of the differential case 61 along the rotation direction of the differential case.
[0016] Incidentally, the vehicle 1 is a vehicle without a control motor provided in a conventional mechanical oil pump device. However, in this vehicle 1, the mechanical oil pump device 100 is devised so that the mechanical oil pump can be driven to supply lubricating oil regardless of whether the vehicle 1 is traveling forward or backward. Hereinafter, the mechanical oil pump device 100 with this devise will be described with reference to FIG.
[0017] FIG. 3 is a configuration diagram of a mechanical oil pump device 100 according to an embodiment of the present invention with this devise. The mechanical oil pump device 100 includes a first intermediate gear 101, a second intermediate gear 102, a first drive gear 103, a second drive gear 104, a counter gear 105, a pump gear 106A, and a mechanical oil pump 106 driven by the pump gear. The mechanical oil pump 106 is an oil pump such as a mechanically operated gear pump, and is equipped with a drive shaft for driving this oil pump, with the pump gear 106A fixed to the end of this drive shaft. By rotating the pump gear 106A of the mechanical oil pump 106, the mechanical oil pump 106 is driven to draw in lubricating oil stored in the case 9 of the 4WD coupling device 90 and supply the drawn lubricating oil to the lubrication target. The first intermediate gear 101 and the second intermediate gear 102 are spaced apart in a direction perpendicular to the rotation axis of the differential case 61, i.e., in the rotational direction of the differential case 61, and each meshes with the transmission gear 66 of the differential case. The first intermediate gear 101 is fixed to one end of the output shaft 101A for transmitting the rotation of the gear and is configured to rotate integrally with the output shaft 101A. The second intermediate gear 102 is fixed to one end of the output shaft 102A for transmitting the rotation of the gear and is configured to rotate integrally with the output shaft 102A.
[0018] The first drive gear 103 is rotatably mounted on the other end of the output shaft 101A of the first intermediate gear 101. It meshes with the pump gear 106A, which is mounted radially to the first drive gear 103. The first drive gear 103 is equipped with a 1-way clutch 103A that allows rotation only in a predetermined direction. Due to the action of this 1-way clutch 103A, the first drive gear 103 rotates together with the first intermediate gear 101 only when rotated in the predetermined direction, and rotates relative to the first intermediate gear 101 and spins freely when rotated in the opposite direction. The counter gear 105 is mounted radially to the first drive gear 103 and meshes with the pump gear 106A of the mechanical oil pump 106. The second drive gear 104 is rotatably mounted on the other end of the output shaft 102A of the second intermediate gear 102. The second drive gear 104 is meshed with a counter gear 105 that is positioned radially to it. In other words, the second drive gear 104 is meshed with the pump gear 106A of the mechanical oil pump 106 via the counter gear 105, which reverses the direction of rotation. The second drive gear 104 is equipped with a one-way clutch 104A that allows rotation only in a predetermined direction. Due to the action of this one-way clutch 104A, the second drive gear 104 rotates together with the second intermediate gear 102 only when rotated in the predetermined direction, and is configured to rotate freely relative to the second intermediate gear 102 when rotated in the opposite direction.
[0019] In this mechanical oil pump device 100, the first intermediate gear 101, the first drive gear 103, and the 1WAY clutch 103A are provided as rotating members for forward movement. Therefore, the 1WAY clutch 103A, which is a rotating member for forward movement, allows the rotation of the differential case 61 (forward rotation) when the vehicle is moving forward, but is configured to block and not transmit the rotation of the differential case 61 (reverse rotation) when the vehicle is moving backward. Specifically, when the vehicle is moving forward and the differential case 61 rotates in the forward direction, the first intermediate gear 101, which meshes with the transmission gear 66 of the differential case 61, rotates in the reverse direction. In this case, the 1WAY clutch 103A is configured to allow the reverse rotation of the first intermediate gear 101, which is the rotation of the differential case 61 transmitted from the transmission gear 66, that is, the forward rotation of the differential case 61. Due to the action of this 1-way clutch 103A, the reverse rotation of the first intermediate gear 101 is transmitted to the pump gear 106A by the first drive gear 103 which rotates together with the first intermediate gear 101, and as a result the pump gear 106A rotates in the forward direction.
[0020] On the other hand, when the vehicle is moving in reverse and the differential case 61 rotates in the reverse direction, the first intermediate gear 101, which meshes with the transmission gear 66 of the differential case 61, rotates in the forward direction. In this case, the 1-way clutch 103A is configured to block the transmission of the forward rotation of the first intermediate gear 101, which is the rotation of the differential case 61 transmitted from the transmission gear 66, i.e., the reverse rotation of the differential case 61. Due to the action of this 1-way clutch 103A, the first drive gear 103 can rotate relative to the first intermediate gear 101, so the forward rotation of the first intermediate gear 101, which would cause the mechanical oil pump 106 to rotate in the reverse direction, is not transmitted to the pump gear 106A.
[0021] Furthermore, the mechanical oil pump device 100 is provided with a second intermediate gear 102, a second drive gear 104, and a 1-way clutch 104A as rotating members for reverse movement. Therefore, the 1-way clutch 104A, which is a rotating member for reverse movement, is configured to allow the rotation (reverse rotation) of the differential case 61 when the vehicle is moving in reverse, but to block and not transmit the rotation (forward rotation) of the differential case 61 when the vehicle is moving forward. Specifically, when the vehicle is moving in reverse and the differential case 61 rotates in reverse, the second intermediate gear 102, which meshes with the transmission gear 66 of the differential case 61, rotates in the forward direction. In this case, the 1-way clutch 104A is configured to allow the forward rotation of the second intermediate gear 102, that is, the reverse rotation of the differential case 61, as the rotation of the differential case 61 transmitted from the transmission gear 66. Due to the action of this 1-way clutch 104A, the forward rotation of the second intermediate gear 102 is transmitted from the second drive gear 104, which rotates together with the second intermediate gear 102, to the pump gear 106A via the counter gear 105 that meshes with it. In other words, the forward rotation of the second intermediate gear 102 is transmitted to the second drive gear 104 as the forward rotation of that gear, then reversed by the counter gear 105 that meshes with the second drive gear 104 to become reverse rotation, and finally this reverse rotation is transmitted to the pump gear 106A. As a result, the pump gear 106A begins to rotate in the forward direction.
[0022] On the other hand, when the vehicle is moving forward and the differential case 61 rotates in the forward direction, the second intermediate gear 102, which meshes with the transmission gear 66 of the differential case 61, rotates in the reverse direction. In this case, the 1WAY clutch 104A is configured to block the transmission of the reverse rotation of the second intermediate gear 102, which is the rotation of the differential case 61 transmitted from the transmission gear 66, i.e., the forward rotation of the differential case 61. Due to the action of this 1WAY clutch 104A, the second drive gear 104 can rotate relative to the second intermediate gear 102, so the reverse rotation of the second intermediate gear 102, which would cause the mechanical oil pump 106 to rotate in the reverse direction, is not transmitted to the pump gear 106A. Thus, in the mechanical oil pump device 100, the 1-way clutches 103A and 104A are configured such that their permitted directions of rotation are opposite to each other.
[0023] The operation of the mechanical oil pump device 100 according to one embodiment of the present invention will be described below with reference to Figure 4. When vehicle 1 is moving forward, the differential case 61 rotates in the forward direction, and in the mechanical oil pump device 100, the forward rotation of the differential case is transmitted to the first intermediate gear 101 and the second intermediate gear 102, which mesh with the transmission gear 66 of the differential case, via the transmission gear 66 of the differential case. Here, the first intermediate gear 101, which receives this forward rotation, rotates in the opposite direction. Also, the 1-way clutch 103A of the first drive gear 103 is configured to allow the transmission of rotation in that direction (reverse rotation), and therefore this rotation is transmitted to the first drive gear 103. In other words, when vehicle 1 is moving forward, the rotation (forward rotation) of the differential case 61 is allowed by the 1-way clutch 103A, so in this case, both the first intermediate gear 101 and the first drive gear 103 rotate in the opposite direction. Then, the reverse rotation of the first drive gear 103 causes the pump gear 106A, which is meshed with it, to rotate in the opposite direction, thereby driving the mechanical oil pump 106 and causing lubricating oil to be discharged from the pump.
[0024] On the other hand, the second intermediate gear 102, which receives forward rotation via the transmission gear 66 of the differential case 61, also rotates in the opposite direction. Here, the 1WAY clutch 104A of the second drive gear 104 is configured to block and not transmit rotation in that direction (reverse rotation), and therefore this rotation is not transmitted to the second drive gear 104. In other words, when the vehicle 1 is moving forward, the rotation (forward rotation) of the differential case 61 is blocked by the 1WAY clutch 104A. Therefore, in this case, the second intermediate gear 102 rotates (reverse rotation), but the second drive gear 104 rotates freely relative to the second intermediate gear 102 (more precisely, it rotates forward as will be explained below).
[0025] Thus, in the mechanical oil pump device 100, when the vehicle 1 is moving forward, the forward rotation of the differential case 61 is transmitted from the transmission gear 66 of the differential case to the first intermediate gear 101. At this time, the 1-way clutch 103A provided on the first drive gear 103, to which the rotation is then transmitted, is configured to allow the forward rotation of the differential case 61. Due to this allowance, the forward rotation of the differential case 61 transmitted to the first intermediate gear 101 becomes the reverse rotation of the gear 101, and is further transmitted to the pump gear 106A as the reverse rotation of the first drive gear 103, which rotates together with the gear 101. Then, the transmission of this reverse rotation causes the pump gear 106A to rotate forward, which drives the mechanical oil pump 106 and causes lubricating oil to be discharged from the pump. Furthermore, the pump gear 106A of the mechanical oil pump meshes with the counter gear 105, so when the pump gear 106A rotates (forward rotation), the counter gear 105 rotates in the opposite direction (reverse rotation). As a result, the second drive gear 104, which meshes with the counter gear 105, is in a state where it can rotate relative to the second intermediate gear 102 in this case, and therefore rotates forward in response to the reverse rotation of the counter gear 105.
[0026] Furthermore, when vehicle 1 is moving in reverse, the differential case 61 rotates in the reverse direction. In the mechanical oil pump device 100, this reverse rotation of the differential case is transmitted to the second intermediate gear 102 and the first intermediate gear 101, which mesh with the transmission gear 66, via the transmission gear 66 of the differential case. Here, the second intermediate gear 102, which receives this reverse rotation, rotates in the opposite direction. Also, the 1-way clutch 104A of the second drive gear 104 is configured to allow the transmission of rotation in that direction (forward rotation), and therefore this rotation is transmitted to the second drive gear 104. In other words, when vehicle 1 is moving in reverse, the rotation (reverse rotation) of the differential case 61 is allowed by the 1-way clutch 104A, so in this case, both the second intermediate gear 102 and the second drive gear 104 rotate in the forward direction. The forward rotation of the second drive gear 104 causes the counter gear 105, which meshes with it, to rotate in the opposite direction. This reverse rotation is then transmitted to the pump gear 106A, which meshes with the counter gear 105, causing the pump gear to rotate in the opposite direction. As a result of the pump gear 106A rotating in the forward direction, the mechanical oil pump 106 is driven, and lubricating oil is discharged from the pump.
[0027] On the other hand, the first intermediate gear 101, which receives reverse rotation via the transmission gear 66 of the differential case 61, also rotates in the opposite direction. Here, the 1WAY clutch 103A of the first drive gear 103 is configured to block and not transmit rotation in that direction (forward rotation), and therefore this rotation is not transmitted to the first drive gear 103. In other words, when the vehicle 1 is moving in reverse, the rotation (reverse rotation) of the differential case 61 is blocked by the 1WAY clutch 103A. Therefore, in this case, the first intermediate gear 101 rotates (forward rotation), but the first drive gear 103 rotates freely relative to the first intermediate gear 101 (more precisely, it rotates in the opposite direction as will be explained below).
[0028] Thus, in the mechanical oil pump device 100, when the vehicle 1 is moving in reverse, the reverse rotation of the differential case 61 is transmitted from the transmission gear 66 of the differential case to the second intermediate gear 102. At this time, the 1-way clutch 104A provided on the second drive gear 104, to which the rotation is then transmitted, is configured to allow the reverse rotation of the differential case 61. Due to this allowance, the reverse rotation of the differential case 61 is transmitted to the second intermediate gear 102 as the forward rotation of the gear, and then to the pump gear 106A as the forward rotation of the second drive gear 104 which rotates together with the gear 102, and further as the reverse rotation of the counter gear 105. Then, the pump gear 106A rotates forward due to the transmission of this reverse rotation, which drives the mechanical oil pump 106 and causes lubricating oil to be discharged from the pump. Furthermore, the pump gear 106A of the mechanical oil pump is also meshed with the first drive gear 103. In this case, the first drive gear 103 is in a state where it can rotate relative to the first intermediate gear 101. As a result, the first drive gear 103, which meshes with the pump gear 106A, rotates in the reverse direction in response to the forward rotation of the pump gear 106A. By using a mechanical oil pump device 100 with this configuration, the mechanical oil pump can be driven and lubricating oil supplied to the object being lubricated regardless of whether the vehicle is moving forward or backward.
[0029] Incidentally, when a vehicle is moving, the load on the vehicle is generally greater when moving forward than when moving backward. Therefore, it is preferable to increase the amount of lubricating oil discharged by the mechanical oil pump when moving forward. To address this, it is necessary to increase the rotational speed of the pump gear when moving forward. In the mechanical oil pump device 100, as described above, the pump gear 106A is driven via the first intermediate gear 101 and the first drive gear 103 when the vehicle 1 is moving forward, and via the second intermediate gear 102 and the second drive gear 104 when it is moving backward. Therefore, by changing the gear ratio between the pump gear 106A, the first drive gear 103, and the second drive gear 104, or the gear ratio between the transmission gear 66, the first intermediate gear 101, and the second intermediate gear 102, the rotational speed of the pump gear 106A can be increased when the vehicle is moving forward. More specifically, the rotational speed of the pump gear 106A during forward movement can be increased by setting the gear ratios between these gears such that the rotational speed of the first drive gear 103 required for the rotation of the pump gear 106A (for example, one rotation) is smaller than the rotational speed of the second drive gear 104, or the rotational speed of the first intermediate gear 101 is smaller than the rotational speed of the second intermediate gear 102. In other words, the rotational speed of the pump gear 106A during forward movement can be increased by setting the gear ratios between these gears such that the gear ratio between the pump gear 106A and the first drive gear 103 is smaller than the gear ratio between the pump gear 106A and the second drive gear 104, or the gear ratio between the transmission gear 66 and the first intermediate gear 101 is smaller than the gear ratio between the transmission gear 66 and the second intermediate gear 102.
[0030] Next, a modified example of the mechanical oil pump device 100 described above will be explained with reference to Figure 5. Figure 5 is a diagram showing the configuration of a modified mechanical oil pump device 200. The mechanical oil pump device 200 includes a first intermediate gear 201, a second intermediate gear 202, a first drive gear 203, a second drive gear 204, a counter gear 205, a pump gear 206A, and a mechanical oil pump 206 driven by the pump gear. Similar to the mechanical oil pump device 100 described above, the mechanical oil pump device 200 is configured such that the rotation of the differential case is transmitted by a transmission gear 66 on the outer circumference of the differential case 61, thereby driving the mechanical oil pump 206 of this device 200.
[0031] The first intermediate gear 201 is mounted in a direction perpendicular to the rotation axis of the differential case 61, i.e., in the direction of rotation of the differential case 61, and meshes with the transmission gear 66 of the differential case. This first intermediate gear 201 is fixed to one end of the output shaft 201A for transmitting the rotation of the gear and is configured to rotate integrally with the output shaft 201A. The first drive gear 203 is rotatably mounted on the other end of the output shaft 201A and meshes with the pump gear 206A of the mechanical oil pump 206. This first drive gear 203 is equipped with a 1-way clutch 203A that allows rotation only in a predetermined direction. Due to the action of this 1-way clutch 203A, the first drive gear 203 rotates together with the first intermediate gear 201 only when rotated in the predetermined direction, and is configured to rotate relative to the first intermediate gear 201 and spin freely when rotated in the opposite direction.
[0032] The counter gear 205 is fixed on the output shaft 201A of the first intermediate gear 201, between the first intermediate gear 201 and the first drive gear 203. That is, the first intermediate gear 201 and the counter gear 205 are configured to rotate together. The second intermediate gear 202 is provided in a direction perpendicular to the axis of the output shaft 201A of the first intermediate gear 201, i.e., in the radial direction of the counter gear 205, and meshes with the counter gear 205. In other words, in the mechanical oil pump device 200, the rotation of the differential case 61 is transmitted to the second intermediate gear 202 via the counter gear 205, which reverses the direction of rotation. Furthermore, the second intermediate gear 202 is fixed to one end of the output shaft 202A for transmitting the rotation of the gear, and is configured to rotate together with the output shaft 202A. The second drive gear 204 is rotatably mounted on the other end of the output shaft 202A of the second intermediate gear 202 and meshes with the pump gear 206A of the mechanical oil pump 206. The second drive gear 204 is equipped with a one-way clutch 204A that allows rotation only in a predetermined direction. Due to the action of this one-way clutch 204A, the second drive gear 204 rotates together with the second intermediate gear 202 only when rotated in the predetermined direction, and is configured to rotate freely relative to the second intermediate gear 202 when rotated in the opposite direction.
[0033] In this mechanical oil pump device 200, the first intermediate gear 201, the first drive gear 203, and the 1WAY clutch 203A are provided as rotating members for forward movement. Therefore, the 1WAY clutch 203A, which is a rotating member for forward movement, is configured to allow the rotation (forward rotation) of the differential case 61 when the vehicle is moving forward, but to block and not transmit the rotation (reverse rotation) of the differential case 61 when the vehicle is moving backward. Specifically, when the vehicle is moving forward and the differential case 61 is rotating in the forward direction, the first intermediate gear 201, which meshes with the transmission gear 66 of the differential case 61, rotates in the reverse direction. In this case, the 1WAY clutch 203A is configured to allow the reverse rotation of the first intermediate gear 201, which is the rotation of the differential case 61 transmitted from the transmission gear 66, that is, the forward rotation of the differential case 61. Due to the action of this 1-way clutch 203A, the reverse rotation of the first intermediate gear 201 is transmitted to the pump gear 206A by the first drive gear 203 which rotates together with the first intermediate gear 201, resulting in the pump gear 206A rotating in the forward direction.
[0034] On the other hand, when the vehicle is moving in reverse and the differential case 61 rotates in the reverse direction, the first intermediate gear 201, which meshes with the transmission gear 66 of the differential case 61, rotates in the forward direction. In this case, the 1-way clutch 203A is configured to block the transmission of the forward rotation of the first intermediate gear 201, which is the rotation of the differential case 61 transmitted from the transmission gear 66, i.e., the reverse rotation of the differential case 61. Due to the action of this 1-way clutch 203A, the first drive gear 203 can rotate relative to the first intermediate gear 201, so the forward rotation of the first intermediate gear 201, which would cause the mechanical oil pump 206 to rotate in the reverse direction, is not transmitted to the pump gear 206A.
[0035] Furthermore, the mechanical oil pump device 200 is provided with a second intermediate gear 202, a second drive gear 204, and a 1-way clutch 204A as rotating members for reverse movement. Therefore, the 1-way clutch 204A, which is a rotating member for reverse movement, allows the differential case 61 to rotate (reverse rotation) when the vehicle is moving in reverse, but is configured to block and not transmit the rotation (forward rotation) of the differential case 61 when the vehicle is moving forward. Specifically, when the vehicle is moving in reverse and the differential case 61 rotates in reverse, the first intermediate gear 201, which meshes with the transmission gear 66 of the differential case 61, rotates in the forward direction, and the counter gear 205 fixed on the output shaft 201A of the first intermediate gear 201 also rotates in the forward direction. Then, this forward rotation of the counter gear 205 causes the second intermediate gear 202, which meshes with it, to rotate in reverse. In this case, the 1WAY clutch 204A is configured to allow the reverse rotation of the second intermediate gear 202, which is the rotation of the differential case 61 transmitted from the transmission gear 66, i.e., the reverse rotation of the differential case 61. Due to the action of the 1WAY clutch 204A, the reverse rotation of the second intermediate gear 202 is transmitted from the second drive gear 204, which rotates (in the opposite direction) with the second intermediate gear 202, to the pump gear 206A that meshes with it, and as a result the pump gear 206A rotates in the forward direction.
[0036] On the other hand, when the vehicle is moving forward and the differential case 61 rotates in the forward direction, the first intermediate gear 201, which meshes with the transmission gear 66 of the differential case 61, rotates in the reverse direction, and the counter gear 205 fixed on the output shaft 201A of the first intermediate gear 201 also rotates in the reverse direction. This reverse rotation of the counter gear 205 causes the second intermediate gear 202, which meshes with it, to rotate in the forward direction. In this case, the 1WAY clutch 204A is configured to block the transmission of the forward rotation of the second intermediate gear 202, which is the rotation of the differential case 61 transmitted from the transmission gear 66, thus preventing the transmission of the forward rotation of the differential case 61. Due to the action of the 1WAY clutch 204A, the second drive gear 204 can rotate relative to the second intermediate gear 202, so the forward rotation of the second intermediate gear 202, which would cause the mechanical oil pump 206 to rotate in the reverse direction, is not transmitted to the pump gear 206A. Thus, in the mechanical oil pump device 200, the 1-way clutches 203A and 204A are configured such that they allow the same direction of rotation for the rotation transmitted from the intermediate gear, that is, they allow opposite directions of rotation for the rotation of the differential case 61.
[0037] The operation of the modified mechanical oil pump device 200 will be explained below with reference to Figure 6. When vehicle 1 is moving forward, the differential case 61 rotates in the forward direction, so the mechanical oil pump device 200 transmits the forward rotation of the differential case to the first intermediate gear 201 which meshes with the transmission gear 66 via the transmission gear 66 of the differential case. Here, the first intermediate gear 201, which has received this forward rotation, rotates in the opposite direction. Also, the 1-way clutch 203A of the first drive gear 203 is configured to allow the transmission of rotation in that direction (reverse rotation), and therefore this rotation is transmitted to the first drive gear 203. In other words, when vehicle 1 is moving forward, the rotation (forward rotation) of the differential case 61 is allowed by the 1-way clutch 203A, so in this case, both the first intermediate gear 201 and the first drive gear 203 rotate in the opposite direction. Then, the reverse rotation of the first drive gear 203 causes the pump gear 206A, which is meshed with it, to rotate in the opposite direction, thereby driving the mechanical oil pump 206 and causing lubricating oil to be discharged from the pump.
[0038] On the other hand, when the first intermediate gear 201 rotates in the reverse direction as described above, the counter gear 205, which is fixed to the output shaft 201A and configured to rotate integrally with the first intermediate gear 201, also rotates in the reverse direction. Furthermore, when the counter gear 205 rotates in the reverse direction, the second intermediate gear 202, which meshes with it, rotates in the opposite direction (forward rotation). Here, the 1WAY clutch 204A of the second drive gear 204 is configured to block and not transmit rotation in that direction (forward rotation), and therefore this rotation is not transmitted to the second drive gear 204. In other words, when the vehicle 1 is moving forward, the rotation (forward rotation) of the differential case 61 is blocked by the 1WAY clutch 204A. Therefore, in this case, the second intermediate gear 202 rotates (forward rotation), but the second drive gear 204 rotates freely relative to the second intermediate gear 202 (more precisely, it rotates in the reverse direction as described below).
[0039] Thus, in the mechanical oil pump device 200, when the vehicle 1 is moving forward, the forward rotation of the differential case 61 is transmitted from the transmission gear 66 of the differential case to the first intermediate gear 201. At this time, the 1-way clutch 203A provided on the first drive gear 203, to which the rotation is then transmitted, is configured to allow the forward rotation of the differential case 61. Due to this allowance, the forward rotation of the differential case 61 transmitted to the first intermediate gear 201 becomes the reverse rotation of the gear 201, and is further transmitted to the pump gear 206A as the reverse rotation of the first drive gear 203, which rotates together with the gear 201. Then, the transmission of this reverse rotation causes the pump gear 206A to rotate forward, which drives the mechanical oil pump 206 and causes lubricating oil to be discharged from the pump. Furthermore, the pump gear 206A of the mechanical oil pump is also meshed with the second drive gear 204. Therefore, when the pump gear 206A rotates (forward), the second drive gear 204 rotates in the opposite direction (reverse). As a result, the second drive gear 204, which meshes with the pump gear 206A, is in a state where it can rotate relative to the second intermediate gear 202 in this case, and thus rotates in the reverse direction in response to the forward rotation of the pump gear 206A.
[0040] Furthermore, when vehicle 1 is moving in reverse, the differential case 61 rotates in the reverse direction. In the mechanical oil pump device 200, this reverse rotation of the differential case is transmitted to the first intermediate gear 201, which meshes with the transmission gear 66, via the transmission gear 66 of the differential case. The first intermediate gear 201, upon receiving this reverse rotation, rotates in the opposite direction. When the first intermediate gear 201 rotates in the forward direction, the counter gear 205, which is fixed to the output shaft 201A and configured to rotate integrally with the first intermediate gear 201, also rotates in the forward direction. When the counter gear 205 rotates in the forward direction, the second intermediate gear 202, which meshes with it, rotates in the opposite direction (reverse rotation). The 1-way clutch 204A of the second drive gear 204 is configured to allow the transmission of rotation in that direction (reverse rotation), and therefore this rotation is transmitted to the second drive gear 204. In other words, when vehicle 1 is moving in reverse, the rotation (reverse rotation) of the differential case 61 is permitted by the 1-way clutch 204A, so in this case, both the second intermediate gear 202 and the second drive gear 204 rotate in opposite directions. Then, this reverse rotation of the second drive gear 204 causes the pump gear 206A, which is meshed with it, to rotate in the opposite direction, thereby driving the mechanical oil pump 206 and causing lubricating oil to be discharged from the pump.
[0041] On the other hand, as described above, the first intermediate gear 201 rotates in the forward direction, but the 1-way clutch 203A of the first drive gear 203 is configured to block and not transmit rotation in that direction (forward rotation). Therefore, this rotation (forward rotation) is not transmitted to the first drive gear 203. In other words, when the vehicle 1 is moving in reverse, the rotation (reverse rotation) of the differential case 61 is blocked by the 1-way clutch 203A. Therefore, in this case, the first intermediate gear 201 rotates (forward rotation), but the first drive gear 203 rotates freely relative to the first intermediate gear 201 (more precisely, it rotates in the reverse direction as described below).
[0042] Thus, in the mechanical oil pump device 200, when the vehicle 1 is moving in reverse, the reverse rotation of the differential case 61 is transmitted from the transmission gear 66 of the differential case to the first intermediate gear 201 as the forward rotation of the gear 201. When the first intermediate gear 201 rotates in the forward direction as a result of this transmission, the counter gear 205 fixed on the output shaft 201A of the gear also rotates in the forward direction in the same direction, and the second intermediate gear 202 that meshes with it rotates in the reverse direction. At this time, the 1-way clutch 204A provided on the second drive gear 204, which then receives the rotation, is configured to allow the reverse rotation of the differential case 61, that is, the reverse rotation of the second intermediate gear 202 as a result of the transmission of the differential case's rotation. With this allowance, the reverse rotation of the differential case 61 is transmitted to the pump gear 206A as the reverse rotation of the second drive gear 204, which rotates together with the second intermediate gear 202. Then, this reverse rotation transmission causes the pump gear 206A to rotate in the forward direction, which drives the mechanical oil pump 206 and causes lubricating oil to be discharged from the pump.
[0043] Furthermore, the pump gear 206A of the mechanical oil pump is also meshed with the first drive gear 203. In this case, the first drive gear 203 is in a state where it can rotate relative to the first intermediate gear 201. As a result, the first drive gear 203, which meshes with the pump gear 206A, rotates in the reverse direction in response to the forward rotation of the pump gear 206A. By using a mechanical oil pump device 200 with this configuration, the mechanical oil pump can be driven and lubricating oil supplied to the object being lubricated regardless of whether the vehicle is moving forward or backward.
[0044] The configuration features of a mechanical oil pump device 100 and a modified mechanical oil pump device 200 according to one embodiment of the present invention will be described below with reference to Figure 7. In the mechanical oil pump device 100 according to one embodiment of the present invention, when viewed in a direction perpendicular to the rotation axis of the gears, the transmission gear 66 of the differential case 61, the first intermediate gear 101 and the second intermediate gear 102 are arranged in the first row. In the second row adjacent to the first row in the direction of the rotation axis of the gears, the first drive gear 103, the pump gear 106A, the counter gear 105 and the second drive gear 104 are arranged. On the other hand, in the modified mechanical oil pump device 200, when viewed similarly, the transmission gear 66 of the differential case 61 and the first intermediate gear 201 are arranged in the first row. In the second row adjacent to the first row in the direction of the rotation axis of the gears, the second intermediate gear 202 and the counter gear 205 are arranged. Next to it, in the third row, are the second drive gear 204, the pump gear 206A, and the first drive gear 203. In other words, the mechanical oil pump device 100 has one fewer gear row than the mechanical oil pump device 200, and therefore has a more compact configuration in the direction of the rotation axis (or vehicle width direction) compared to device 200.
[0045] On the other hand, the mechanical oil pump device 200 has a configuration in which the counter gear 105 is moved and integrated from the second row of four gears in device 100 to the middle of the output shaft 201A, which is equipped with the first intermediate gear 201 and the first drive gear 203. In other words, the mechanical oil pump device 200 has a configuration in which the counter gear 205, the first intermediate gear 201, and the first drive gear 203 are coaxially mounted on one output shaft 201A. As a result, the mechanical oil pump device 200 has one less gear than the second row of four gears in the mechanical oil pump device 100, and the remaining three gears form a third row. Therefore, the mechanical oil pump device 200 has a configuration in which the maximum number of gears arranged in a row is less than that of device 100 when viewed in the direction perpendicular to the rotation axis of the gears, i.e., in the radial direction of the gears, resulting in a compact configuration in the radial direction of the gears (or in the longitudinal direction of the vehicle).
[0046] The above description focuses on an embodiment of a part-time four-wheel drive vehicle of the FR (front-engine, rear-drive) type. However, the mechanical oil pump device according to the present invention is also applicable to FF (front-engine, front-drive) type part-time four-wheel drive vehicles. Furthermore, the mechanical oil pump device according to the present invention can be applied not only to vehicles powered by an engine, but also to vehicles powered by an electric motor. [Explanation of Symbols]
[0047] 1 vehicle, 4. Transfer device, 17,18 Front axle shaft, 6. Front differential (differential gear), 61 Differential case, 66 transmission gears, 7 couplings, 72,73 Clutch, 9 cases, 90 4WD coupling device, 100,200 Mechanical oil pump devices, 101,201 First intermediate gear, 101A, 201A output shaft, 102,202 Second intermediate gear, 102A, 202A output shaft, 103,203 First drive gear, 103A, 203A 1WAY clutch, 104,204 Second drive gear, 104A, 204A 1WAY clutch, 105,205 counter gear, 106A, 206A pump gear, 106,206 Mechanical oil pumps
Claims
1. A transmission gear for transmitting the rotation of the differential case is provided on the outer circumference of the differential case, which constitutes the differential gear of the vehicle, along its rotational direction, The rotation of the differential case is transmitted via the transmission gear to a first intermediate gear and a second intermediate gear, A first drive gear to which the rotation of the differential case is transmitted from the first intermediate gear, the first drive gear configured to allow the transmission of the rotation only when the rotation of the differential case is the rotation when the vehicle is moving forward, A second drive gear to which the rotation of the differential case is transmitted from the second intermediate gear, the second drive gear is configured to allow the transmission of the rotation only when the rotation of the differential case is the rotation when the vehicle is moving in reverse, A mechanical oil pump having a pump gear, which is driven by the rotation of the differential case transmitted to the pump gear to supply lubricating oil to the object to be lubricated, Equipped with, The pump gear is configured such that when the rotation of the differential case is the rotation of the vehicle moving forward, the rotation of the differential case is transmitted from the first drive gear, and when the rotation of the differential case is the rotation of the vehicle moving backward, the rotation of the differential case is transmitted from the second drive gear. The first intermediate gear is provided so as to mesh with the transmission gear in the rotational direction of the differential case, and is configured to transmit the rotation of the differential case. The first drive gear is provided with the same axis of rotation as the first intermediate gear and is configured to rotate together with the first intermediate gear when the transmission of rotation is permitted. The second intermediate gear is provided radially to a counter gear for reversing the direction of rotation, which is provided between the first intermediate gear and the first drive gear with the same axis of rotation so as to rotate together with the first intermediate gear, and is configured to mesh with the counter gear. The second drive gear is provided with the same axis of rotation as the second intermediate gear and is configured to rotate together with the second intermediate gear when the transmission of rotation is permitted. The pump gear is provided in the radial direction of the first drive gear and the second drive gear, and is configured to mesh directly with both of these gears. A mechanical oil pump device characterized by the following features.
2. A transmission gear for transmitting the rotation of a differential case, which is provided on the outer circumference of a differential case constituting a differential device of a vehicle, along its rotational direction, The rotation of the differential case is transmitted via the transmission gear to a first intermediate gear and a second intermediate gear, A first drive gear to which the rotation of the differential case is transmitted from the first intermediate gear, the first drive gear configured to allow the transmission of the rotation only when the rotation of the differential case is the rotation when the vehicle is moving forward, A second drive gear to which the rotation of the differential case is transmitted from the second intermediate gear, the second drive gear is configured to allow the transmission of the rotation only when the rotation of the differential case is the rotation when the vehicle is moving in reverse, A mechanical oil pump having a pump gear, which is driven by the rotation of the differential case transmitted to the pump gear to supply lubricating oil to the object to be lubricated, Equipped with, The pump gear is a mechanical oil pump device configured such that when the rotation of the differential case is the rotation of the vehicle moving forward, the rotation of the differential case is transmitted from the first drive gear, and when the rotation of the differential case is the rotation of the vehicle moving backward, the rotation of the differential case is transmitted from the second drive gear. A coupling having a clutch capable of controlling a tightened state that transmits the driving force caused by the rotation of the differential case to one side of the axle shaft to the wheels, and a released state that interrupts the transmission of the driving force to the other side, A case housing the coupling and the mechanical oil pump device, Equipped with, The mechanical oil pump device is configured to supply lubricating oil stored in the case to the clutch of the coupling. A 4WD coupling device characterized by the following.
3. In the 4WD coupling device according to Claim 2, The aforementioned mechanical oil pump device is, The first intermediate gear and the second intermediate gear are spaced apart so as to mesh with the transmission gear in the rotational direction of the differential case, and are configured to transmit the rotation of the differential case. The first drive gear is provided with the same axis of rotation as the first intermediate gear and is configured to rotate together with the first intermediate gear when the transmission of rotation is permitted. The second drive gear is provided with the same axis of rotation as the second intermediate gear and is configured to rotate together with the second intermediate gear when the transmission of rotation is permitted. The pump gear is provided radially to the first drive gear and the second drive gear, and is configured to mesh directly with the first drive gear and with the second drive gear via a counter gear for reversing the direction of rotation. A 4WD coupling device characterized by the following.
4. In the 4WD coupling device according to Claim 2, The aforementioned mechanical oil pump device is, The first intermediate gear is provided so as to mesh with the transmission gear in the rotational direction of the differential case, and is configured to transmit the rotation of the differential case. The first drive gear is provided with the same axis of rotation as the first intermediate gear and is configured to rotate together with the first intermediate gear when the transmission of rotation is permitted. The second intermediate gear is provided radially to a counter gear for reversing the direction of rotation, which is provided between the first intermediate gear and the first drive gear with the same axis of rotation so as to rotate together with the first intermediate gear, and is configured to mesh with the counter gear. The second drive gear is provided with the same axis of rotation as the second intermediate gear and is configured to rotate together with the second intermediate gear when the transmission of rotation is permitted. The pump gear is provided in the radial direction of the first drive gear and the second drive gear, and is configured to mesh directly with both of these gears. A 4WD coupling device characterized by the following.
5. In the 4WD coupling device according to claim 3, The aforementioned mechanical oil pump device is, The gear ratios between these gears are set such that the gear ratio between the pump gear and the first drive gear is smaller than the gear ratio between the pump gear and the second drive gear, or the gear ratio between the transmission gear and the first intermediate gear is smaller than the gear ratio between the transmission gear and the second intermediate gear. A 4WD coupling device characterized by the following.