JP6202891B2 - In-wheel motor drive device - Google Patents

Description

  The present invention relates to an in-wheel motor drive device, and more particularly to an in-wheel motor drive device incorporating an oil pump that supplies lubricating oil in synchronization with the rotation of the motor.

  The in-wheel motor drive device is installed in an inner space portion of a wheel of an automobile, and as shown in FIG. 5, a motor 1 that generates a driving force, and a speed reducer that decelerates and outputs the rotation of the motor 1. 2 and a wheel hub 3 for transmitting the output from the speed reducer 2 to the wheel. The motor 1 and the speed reducer 2 are accommodated in a housing 4.

  The housing 4 is provided with an oil tank 5 for lubricating oil at the lower portion, and the lubricating oil in the oil tank 5 is sucked by the oil pump 6 and supplied to the motor 1 and the speed reducer 2 to perform lubrication and cooling. (Patent Document 1).

  An oil supply passage 7 for supplying lubricating oil to the inside of the speed reducer 2 extends rearward along the inside of the housing 4 from the discharge port of the oil pump 6 driven in synchronization with the rotation of the motor 1, and From the end, through the internal passage 9, the internal passage 11 of the input shaft 10 of the speed reducer 2, and the input shaft oil supply holes 12 a and 12 b provided in the input shaft 10 in the radial direction so as to communicate with the internal passage 11. The

The return passage 13 for the lubricating oil is constituted by a discharge port 14 provided at the bottom of the housing 4 of the speed reducer 2 and a passage that reaches the suction port of the oil pump 6 through the oil tank 5.
The flow of the lubricating oil is indicated by broken arrows.

JP 2009-63043 A

  By the way, in the in-wheel motor drive device that supplies the lubricating oil by the oil pump 6 that is driven in synchronization with the rotation of the motor 1 as described above, the oil pump 6 sucks up the lubricating oil when starting or running at a low speed. Since it takes time to supply to the speed reducer 2, there is a possibility that the supply of lubricating oil is small at the start of running or low speed running, resulting in insufficient lubrication and seizure.

  Accordingly, an object of the present invention is to enable a sufficient amount of lubricating oil to be supplied to the speed reducer at the start of running or low speed running, and to prevent seizure due to lack of lubricating oil.

  In order to solve the above-described problems, the present invention provides an in-wheel drive device including an oil pump that is operated by a rotational force of a motor and supplies lubricating oil to a lubricating oil supply passage. A second oil tank is provided in the upper part of the speed reducer, and lubricating oil is supplied from the second oil tank to the speed reducer at the start of running or at a low speed.

  An opening / closing valve is provided at the bottom of the second oil tank, and the lubricating oil in the second oil tank can be supplied to the speed reducer by opening the opening / closing valve.

  By providing a flow direction control valve in the oil supply passage of the oil pump and switching the flow direction control valve, the lubricating oil discharged from the discharge port of the oil pump can be introduced into the second oil tank.

  A heater is installed in the second oil tank, and the oil temperature can be increased when the temperature of the lubricating oil in the second oil tank is low and the viscosity is high.

  By providing the second oil tank on the outer periphery of the housing of the speed reducer, the second oil tank can be easily installed, and oil cooling is also effective.

  As described above, according to the present invention, a sufficient amount of lubricating oil can be supplied to the speed reducer at the start of running or low speed running, and seizure prevention due to lack of lubricating oil can be achieved.

It is sectional drawing which shows embodiment of the in-wheel motor drive device which concerns on this invention. It is a figure which shows the control flow of the on-off valve of a 2nd oil tank. It is a figure which shows the control flow of a flow direction control valve. It is a figure which shows the control flow of ON-OFF of a heater. It is sectional drawing of the in-wheel motor drive device of a prior art example.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the in-wheel motor drive device according to the present invention includes a motor 21 that generates a driving force, a speed reducer 22 that decelerates and outputs the rotation of the motor 21, and an output from the speed reducer 22 as a wheel. The motor 21 and the speed reducer 22 are accommodated in the housing 24. The housing 24 includes a motor housing 24a and a reduction gear housing 24b. The wheel hub 23 is composed of an outer ring held by the speed reducer housing 24b, an inner ring on the inner periphery thereof, and a double-row angular ball bearing composed of double-row balls between the outer rings and the inner ring.

  The reduction gear housing 24b is provided with a first oil tank 25 for lubricating oil at the lower portion, the lubricating oil in the first oil tank 25 is sucked by the oil pump 26, and the lubricating oil is supplied to the motor 21 and the reduction gear 22. Lubricating and cooling.

  An oil supply passage 27 that supplies lubricating oil to the inside of the speed reducer 22 extends rearward along the inside of the motor housing 24 a from the discharge port of an oil pump 26 that is driven in synchronization with the rotation of the motor 21. An internal passage 31 of the input shaft 30 of the speed reducer 22 through the internal passage 29 from the rear end, and input shaft oil supply holes 32a and 32b provided in the input shaft 30 in a radial direction so as to communicate with the internal passage 31 Is done.

  The lubricating oil return passage 33 is constituted by a discharge port 37 provided at the bottom of the speed reducer housing 24 b and a passage through the first oil tank 25 to the suction port of the oil pump 26. The flow of the lubricating oil is as indicated by the dashed arrows.

  In the in-wheel motor drive device according to the present invention, the second oil tank 34 is installed on the top of the speed reducer housing 24b.

  An opening / closing valve 35 is provided at the bottom of the second oil tank 34, and by opening the opening / closing valve 35, the lubricating oil in the second oil tank 34 can be supplied to the speed reducer 22.

  The lubricating oil discharged from the discharge port of the oil pump 26 can be introduced into the second oil tank 34 by switching the flow direction control valve 36 provided in the oil supply passage 27 to the second oil tank 34.

  The on-off valve 35 at the bottom of the second oil tank 34 is opened when the supply of lubricating oil from the first oil tank 25 is difficult to be supplied to the speed reducer 22, such as when starting to run or running at a low speed. Lubricating oil in the tank 34 is supplied to the speed reducer 22. As a result, the lubricating oil is supplied to the speed reducer 22 at the start of running or running at a low speed, and seizure prevention due to lack of lubricating oil can be achieved.

  The volume and the amount of oil of the first oil tank 25 and the second oil tank 34 are such that the first oil tank 25> the second oil tank 34.

  The relationship between the oil supply time to the second oil tank 34 and the oil discharge time for discharging the second oil tank 34 by opening the on-off valve 35 is longer for the oil discharge time. As a guideline, it can be designed on the assumption that the oil supply time until the second oil tank 34 becomes full takes 10 seconds, and that the oil drain time from the full state to the empty state takes about 1 minute.

  The on-off valve 35 at the bottom of the second oil tank 34 is opened and closed according to the control flow shown in FIG. 2, and lubricating oil is supplied from the second oil tank 34 to the speed reducer 22.

  As shown in FIG. 2, first, as shown in step S5, when the vehicle speed is 0 km / h, that is, when the vehicle stops, the control flow returns to the start point of the control flow, and the control of the on-off valve 35 at the bottom of the second oil tank 34 is performed. Start, as in step S1, it is determined whether the vehicle speed at which the vehicle moves forward, the vehicle speed at which the vehicle moves backward, that is, the absolute value of the vehicle speed is 0 km / h, and is determined to be 0 km / h or more. Is started, the on-off valve 35 at the bottom of the second oil tank 34 is opened, and lubricating oil is supplied from the second oil tank 34 to the speed reducer 22 (step S2).

  Thereafter, as shown in step S3, when the on-off valve 35 is opened for 15 seconds and the vehicle speed exceeds 25 km / h, the on-off valve 35 is closed as in step S4.

  The 15 seconds of step S3 is merely an example, but it is desirable to supply the lubricating oil by opening the on-off valve 35 for at least a fixed time from the start of traveling, assuming rapid acceleration. Further, although vehicle speed ≧ 25 km / h is an example, the lubricating oil is replenished from the second oil tank 34 to the speed reducer 22 at the time of low speed traveling from the start of traveling.

  As in step S5, in step S4, the on / off valve 35 of the second oil tank 34 is closed until the vehicle speed reaches 0 km / h, that is, until the vehicle stops. When the vehicle stops, Return to the starting point.

  Next, replenishment of lubricating oil to the second oil tank 34 is performed by switching the flow direction control valve 36 provided in the oil supply passage 27 by the control flow of FIG.

  The conditions for setting the flow direction control valve 36 to ON, changing the flow path of the oil supply passage 27 to the second oil tank 34 side, and storing the lubricating oil in the second oil tank 34 are as follows.

  As shown in FIG. 3, first, as in step S6, it is determined whether the vehicle speed at which the vehicle moves forward, the vehicle speed at which the vehicle moves backward, that is, the absolute value of the vehicle speed is 0 km / h, and is determined to be 0 km / h or more. The process proceeds to step S7.

  In step S7, it is determined whether or not the amount of lubricating oil in the second oil tank 34 is the maximum amount, and if it is not the maximum amount, the process proceeds to step S8.

  In step S8, it is determined whether the amount of lubricating oil in the second oil tank 34 is 2/3 or more of the maximum capacity. If the amount of oil is less than 2/3 of the maximum capacity, the process proceeds to step S12. The flow direction control valve 36 is turned ON, the flow path of the oil supply passage 27 is changed to the second oil tank 34 side, and lubricating oil is stored in the second oil tank 34. The threshold value 2/3 of the maximum capacity is merely an example.

  After the flow direction control valve 36 is turned on and the oil supply passage 27 is changed to the second oil tank 34 side, the oil amount in the second oil tank 34 is full (in the second oil tank 34) in step S13. (Oil amount = MAX) or after 10 seconds, the flow direction control valve 36 is turned OFF to stop the supply of lubricating oil to the second oil tank 34. In step S13, the 10 seconds during which the supply of the lubricating oil to the second oil tank 34 is stopped is merely an example. However, if the oil pump 26 rotates at 100 rpm when traveling at 10 km / h, the first operation is performed in about 10 seconds. This is to prevent the lubricating oil from being stored in the oil tank 34 and prevent the lubricating oil from being supplied for a long time to the motor 21 side, thereby protecting the motor 21 side.

  If it is determined in step S8 that the amount of lubricating oil in the second oil tank 34 is 2/3 or more of the maximum capacity, the process proceeds to step S9, where it is determined whether the acceleration is greater than 0, If the acceleration is 0 or less, the process proceeds to step S10, where it is determined whether the vehicle speed is 15 km / h or more (vehicle speed ≧ 15 km / h), and if it is determined that the vehicle speed is less than 15 km / h, The direction control valve 36 is turned ON, the flow path of the oil supply passage 27 is changed to the second oil tank 34 side, and lubricating oil is stored in the second oil tank 34.

  If it is determined in step S10 that the vehicle speed is 15 km / h or more (vehicle speed ≧ 15 km / h), the acceleration is 0 or less in step S9. In order to prevent repetition, the flow direction control valve 36 is kept OFF.

  If it is determined in step S11 that the vehicle speed is 35 km / h or more (vehicle speed ≧ 35 km / h), the vehicle speed is 35 km / h or more during acceleration. The control valve 36 is kept OFF.

  Next, when the vehicle travels back, the flow direction control valve 36 is preferably turned off. The reason is to prevent the oil in the second oil tank 34 from becoming negative due to the reverse rotation of the oil pump, and the oil being sucked up.

  Also, when the on-off valve 35 at the bottom of the second oil tank 34 is opened and the lubricating oil is supplied to the speed reducer 22, if the temperature of the lubricating oil in the second oil tank 34 is low, the viscosity of the lubricating oil increases. , Lubricating oil is difficult to be supplied.

  For this reason, a heater may be installed in the second oil tank 34 to increase the temperature of the lubricating oil, thereby reducing the viscosity of the lubricating oil and facilitating the supply of the lubricating oil.

  The heater in the second oil tank 34 is O-OFF, for example, by the control flow shown in FIG.

  When the amount of lubricating oil in the second oil tank 34 is less than ¼ of the capacity of the second oil tank 34, as shown in step S17, the oil temperature of the lubricating oil does not rise too much. Turn off the heater.

  In step S15, when the amount of lubricating oil in the second oil tank 34 is ¼ or more of the capacity of the second oil tank 34, the process proceeds to step S16, and whether or not the oil temperature is equal to or higher than a threshold value. If the oil temperature is lower than the threshold, the heater is turned on in step S18. If the oil temperature is higher than the threshold, the heater is turned off in step S17.

  Note that the oil temperature threshold is changed depending on the season and region.

  In the first embodiment described above, the example in which the oil supply passage 27 is provided inside the motor housing 24a has been shown. However, the present invention is not limited to this, and for example, a circulation oil passage is provided outside the in-wheel motor drive device. May be.

  Moreover, although the example of the cycloid pump was shown as the oil pump 26, not only this but the rotary pump driven using the rotation of the motor 21 is employable.

  Moreover, although the example which employ | adopted the radial gap motor as the motor 21 was shown, the motor of arbitrary structures is applicable not only to this. For example, it may be an axial gap motor including a stator fixed to the housing and a rotor disposed at a position facing the inner side of the stator with a gap in the axial direction.

  Moreover, although the example of the in-wheel motor drive device which employ | adopted the cycloid reduction mechanism as the reduction gear 22 was shown, arbitrary reduction mechanisms can be employ | adopted not only to this. For example, a planetary gear reduction mechanism, a parallel shaft gear reduction mechanism, or the like is applicable.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

DESCRIPTION OF SYMBOLS 21 Motor 22 Reduction gear 23 Wheel hub 24 Housing 24a Motor housing 24b Reduction gear housing 25 1st oil tank 26 Oil pump 27 Oil supply passage 28 Motor shaft 29 Internal passage 30 Input shaft 31 Internal passage 32a, 32b Input shaft oil supply hole 33 Feedback passage 34 Second oil tank 35 On-off valve 36 Flow direction control valve 37 Discharge port

Claims (3)

An in-wheel provided with a motor, a speed reducer, a wheel hub, and a housing that holds these, and an oil pump that is operated by the rotational force of the motor and supplies lubricating oil to the speed reducer through a lubricating oil supply passage In the drive device, a first oil tank is provided below the rotation shaft of the in-wheel drive device, a second oil tank is provided around the speed reducer and above the rotation shaft, and a flow direction control valve is provided in the oil supply passage of the oil pump. By switching this flow direction control valve, the lubricating oil discharged from the discharge port of the oil pump is introduced into the second oil tank, and an opening / closing valve is provided at the bottom of the second oil tank, and this opening / closing valve is opened. by, characterized in that the lubricating oil in the second oil tank, when beginning run and low-speed running, and to supply the lubricating oil to the reducer from the second oil tank In-wheel drive unit for. The in-wheel drive device according to claim 1 , wherein a heater is installed in the second oil tank. In-wheel drive unit according to claim 1 or 2, characterized in that a second oil tank on the outer periphery of the housing of the speed reducer.

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