WO2014168092A1

WO2014168092A1 - In-wheel motor drive device

Info

Publication number: WO2014168092A1
Application number: PCT/JP2014/059988
Authority: WO
Inventors: 黒田優; 山田航; 鈴木健一
Original assignee: Ntn株式会社
Priority date: 2013-04-12
Filing date: 2014-04-04
Publication date: 2014-10-16
Also published as: JP2014206207A

Abstract

This in-wheel motor drive device is provided with an electric motor (1) for driving a wheel, a wheel bearing (5) for supporting the wheel, and a reduction gear (2) for reducing the rotation of the electric motor (1) and transmitting the reduced rotation to the wheel bearing (5). Further provided is a lubricant reservoir (29) for storing a lubricant, a lubricant supply means (JK) for resupplying the lubricant stored in the lubricant reservoir (29) to the reduction gear (2), and an oil amount detection sensor (40) for detecting the amount of the lubricant, the sensor being provided in the bottom-most part of the lubricant storage part (29). This configuration allows the in-wheel motor drive device to be made more compact and the amount of the lubricant to be detected easily.

Description

In-wheel motor drive device

Related applications

This application claims the priority of Japanese Patent Application No. 2013-083484, filed on April 12, 2013, and is hereby incorporated by reference in its entirety as a part of this application.

The present invention relates to an in-wheel motor driving device used for driving wheels of, for example, an electric vehicle.

In an in-wheel motor drive device, a technique has been proposed in which a pump for circulating lubricating oil is arranged in the middle of a lubricating oil path (Patent Document 1). In this in-wheel motor drive device, a mechanism for detecting the amount of lubricating oil is not disclosed. As a mechanism for detecting the amount of lubricating oil, for example, a so-called float type oil amount detecting mechanism may be provided in the lubricating oil reservoir. In addition, it is conceivable to insert a level gauge or the like into the reservoir when the vehicle is stopped, or to measure the oil amount visually through an inspection window.

JP 2009-63043 A

In the in-wheel motor drive device, the amount of lubricating oil is smaller than that of a general internal combustion engine in order to reduce the unsprung weight while reducing the size. For this reason, in the conventional in-wheel motor drive device, when the amount of lubricating oil decreases excessively during operation and the lubrication of each part is not sufficiently performed, wear or abnormal heat generation may occur in each part. .

When a float type oil amount detection mechanism is provided in the reservoir, it is necessary to increase the volume of the reservoir, resulting in an increase in the size of the device, making the in-wheel motor drive device compact and reducing the unsprung weight. . In addition, the structure becomes complicated and the manufacturing cost increases. When measuring the amount of oil visually, it takes time to measure the amount of oil. For example, when an in-wheel motor drive device is provided for each of the left and right drive wheels, the amount of oil must be measured for each in-wheel motor drive device, which further takes time.

An object of the present invention is to provide an in-wheel motor drive device that can make the in-wheel motor drive device compact and can easily detect the amount of lubricating oil.

An in-wheel motor drive device according to the present invention includes an electric motor that drives a wheel, a wheel bearing that supports the wheel, and a speed reducer that decelerates the rotation of the electric motor and transmits the rotation to the wheel bearing. In the in-wheel motor drive device, a lubricating oil storage unit that stores lubricating oil, a lubricating oil supply unit that supplies the lubricating oil stored in the lubricating oil storage unit to the speed reducer and returns the lubricating oil, and the lubricating oil storage unit An oil amount detection sensor is provided at the lowermost portion to detect the amount of lubricating oil.

According to this configuration, the lubricating oil is temporarily stored in the lubricating oil reservoir. During operation of the vehicle, the lubricating oil supply means supplies the lubricating oil stored in the lubricating oil storage unit to the reduction gear. For example, when the vehicle is stopped, the oil amount of the lubricating oil in the lubricating oil reservoir is detected using the oil amount detection sensor. Since this oil amount detection sensor is provided at the lowermost portion of the lubricating oil reservoir, even if the oil amount is excessively reduced, the oil amount can be detected accurately and easily. Thus, when the amount of oil is excessively reduced, the driver can recognize that fact and take necessary measures such as towing the vehicle and moving it to a repair shop or the like. Thereby, abnormalities, such as excessive wear of a reduction gear, can be prevented beforehand. In addition, since the oil level detection sensor can be easily installed, for example, in the drain plug at the bottom of the lubricating oil reservoir, the in-wheel motor drive device can be made more compact and the unsprung weight can be reduced while improving versatility. Can do.

The oil amount detection sensor may be a pressure sensor or a weight sensor. The relationship between the amount of lubricating oil and the pressure or weight is stored in, for example, a table, and the amount of oil is calculated by comparing the detected value detected by the pressure sensor or weight sensor with the table. Accordingly, it is not necessary to store a relatively large mechanism such as a float type oil amount detection mechanism in the lubricating oil reservoir, and the apparatus can be prevented from being enlarged. In addition, the amount of lubricating oil in the lubricating oil reservoir can be easily detected.

When the oil amount detection sensor is a pressure sensor, the pressure sensor is one of an electronic control unit that performs overall control of the entire vehicle and a motor control device that controls the electric motor via a signal line. It may be connected to. The electric motor has a sensor for detecting a rotation angle of a rotor, and a signal line connected to the pressure sensor, the electronic control unit, and the motor control device is coaxial with a connection cable of the sensor of the electric motor. It may be arranged. You may provide a connection part in the longitudinal direction middle part of the signal wire | line which connects the said oil amount detection sensor, the said electronic control unit, and the said motor control apparatus.

The lubricating oil supply means is provided along a lubricating oil flow path provided in a motor housing of the electric motor and a shaft center in a motor rotating shaft of the electric motor, and is connected to the lubricating oil flow path. An oil path, a speed reducer oil path that is provided in the speed reducer, communicates with the motor rotation shaft oil path and the lubricating oil reservoir, and supplies lubricating oil to the speed reducer, and is stored in the lubricating oil reservoir. An axial oil supply mechanism having a pump that sucks up the lubricating oil and circulates it through the lubricating oil flow path to the motor rotation shaft flow path and the speed reducer oil path may be used. In this case, the lubricating oil is forcibly circulated by the pump through the lubricating oil passage to the motor rotation shaft passage and the speed reducer oil passage. Thereby, lubricating oil can be stably supplied over the whole reduction gear.

After the vehicle stops, there may be provided an arithmetic means for measuring the oil amount of the lubricating oil in the lubricating oil reservoir part a plurality of times by the oil amount detection sensor for a predetermined fixed time and calculating an average value thereof. The “determined fixed time” can be appropriately determined by a test, simulation, or the like. After the vehicle stops, the lubricating oil existing in the oil passage flows into the lubricating oil reservoir. The calculating means can stably determine the oil amount of the lubricating oil by calculating an average value of the oil amounts measured a plurality of times by the oil amount detection sensor in a certain time. When the vehicle is in operation, the lubricating oil is circulated and the sensor output of the oil amount detection sensor is not stable. Therefore, measurement is performed by the oil amount detection sensor after the vehicle stops.

The lubricating oil reservoir may have a mortar-shaped bottom, and the oil amount detection sensor may be provided at the bottom of the mortar-shaped bottom. In this case, the lubricating oil stored in the lubricating oil storage part flows into the lowermost part of the mortar-shaped bottom by the weight of the lubricating oil. For this reason, the amount of lubricating oil can be detected stably.

An abnormality reporting means is provided for outputting abnormality information of the lubricating oil supply means when the oil amount detected by the oil amount detection sensor deviates from a predetermined setting range when the vehicle is stopped when the vehicle is powered on. May be. When the abnormality information of the lubricating oil supply means is output by the abnormality reporting means, the vehicle driver recognizes that fact and takes necessary measures such as towing the vehicle and moving it to a repair shop, for example. Can do. Thereby, abnormalities, such as excessive wear of a reduction gear, can be prevented beforehand. You may provide the said oil amount detection sensor in all the in-wheel motor drive devices mounted in a vehicle, respectively. One or both of a warning display means for receiving a visually checkable warning and a voice output means for outputting sound may be provided in response to the abnormality information output from the abnormality report means.

When the oil amount detected by the oil amount detection sensor is out of a predetermined setting range, output limiting means for limiting the motor torque and the rotation speed of the electric motor may be provided. The output restricting means restricts the output of the electric motor when the detected oil amount is out of the predetermined setting range, thereby preventing the lubricating oil from being insufficiently supplied. Abnormalities such as excessive wear can be prevented.

The output limiting means may be configured to gradually decrease the motor torque of the electric motor and stop driving the electric motor when the oil amount detected by the oil amount detection sensor is out of a predetermined setting range. good. By forcibly limiting the output of the electric motor in this way, it is possible to reliably prevent excessive wear and abnormal heat generation of the reduction gear. Therefore, the abnormality of the in-wheel motor drive device due to excessive reduction of the lubricating oil can be prevented in advance, and the sudden stop while the vehicle is running can be prevented.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or drawings is included in the present invention. In particular, any combination of two or more of each claim in the claims is included in the present invention.

The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same reference numerals in a plurality of drawings indicate the same or corresponding parts.
It is a longitudinal cross-sectional view of the in-wheel motor drive device which concerns on 1st Embodiment of this invention. It is an expanded sectional view of the lubricating oil storage part of the same in-wheel motor drive device. It is a block diagram of a control system of the in-wheel motor drive device. It is a figure which shows the relationship between the weight detected by the weight sensor of the in-wheel motor drive device, and the amount of oil. It is a figure which shows roughly the electric vehicle carrying the same in-wheel motor drive device.

An in-wheel motor drive device according to a first embodiment of the present invention will be described with reference to FIGS. The following description also includes a description of the control method of the in-wheel motor drive device. As shown in FIG. 1, the in-wheel motor drive device includes an electric motor 1 that drives wheels, a speed reducer 2 that decelerates the rotation of the electric motor 1, and an output that is coaxial with the input shaft 3 of the speed reducer 2. A wheel bearing 5 rotated by the member 4 and a lubricating oil supply means Jk are provided. The reduction gear 2 is interposed between the wheel bearing 5 and the electric motor 1, and the wheel hub, which is a driving wheel supported by the wheel bearing 5, and the motor rotating shaft 6 of the electric motor 1 are coaxially arranged. It is connected.

A suspension (not shown) in the vehicle is connected to the reduction gear housing 7 that houses the reduction gear 2. In this specification, the side closer to the outside in the vehicle width direction of the vehicle with the in-wheel motor drive device supported by the vehicle is called the outboard side, and the side closer to the center of the vehicle is called the inboard side. .

The electric motor 1 is a radial gap type IPM motor (so-called embedded magnet type synchronous motor) in which a radial gap is provided between a motor stator 9 fixed to a motor housing 8 and a motor rotor 10 attached to the motor rotating shaft 6. . The motor housing 8 is provided with

bearings

11 and 12 spaced apart in the axial direction, and the motor rotating shaft 6 is rotatably supported by the

bearings

11 and 12. The motor rotating shaft 6 transmits the driving force of the electric motor 1 to the speed reducer 2. A flange portion 6 a extending radially outward is provided in the vicinity of the intermediate portion in the axial direction of the motor rotating shaft 6, and the motor rotor 10 is attached to the flange portion 6 a via a rotor fixing member 13.

The input shaft 3 of the speed reducer 2 has one axial end extending into the motor rotating shaft 6 and is splined to the motor rotating shaft 6. A bearing 14a is fitted in the cup portion 4a of the output member 4, and a bearing 14b is fitted in a cylindrical connecting member 26 connected to the cup portion 4a via an inner pin 22. The input shaft 3 is rotatably supported by these

bearings

14a and 14b. Therefore, the input shaft 3 and the motor rotating shaft 6 of the speed reducer 2 are supported by the

bearings

11, 12, 14a, and 14b so as to be integrally rotatable.

Eccentric portions

15 and 16 are provided on the outer peripheral surface of the input shaft 3 in the speed reducer housing 7. These

eccentric portions

15 and 16 are provided with a 180 ° phase shift so that the centrifugal force due to the eccentric motion is canceled out from each other.

The reduction gear 2 may have a reduction ratio of 6 or more, for example. The speed reducer 2 is a cycloid speed reducer including an inner housing Ih, curved

plates

17 and 18, a plurality of outer pins 19, a motion conversion mechanism 20, and a counterweight 21. The

curved plates

17 and 18 are curved (waveform) shapes whose outer periphery curves alternately inward and outward in the radial direction, and are respectively provided rotatably in the

eccentric portions

15 and 16. An inner housing Ih is connected to the reducer housing 7, and the output member 4 and the connecting member 26 are rotatably supported on the inner periphery of the inner housing Ih via

bearings

27a and 27b.

The inner housing Ih is provided with a plurality of outer pins 19 at regular intervals in the circumferential direction via needle roller bearings. The outer periphery of the

curved plates

17 and 18 is configured to be able to make rolling contact with these outer pins 19. When the

curved plates

17 and 18 revolve, the corrugated portions on the outer periphery of the

curved plates

17 and 18 and the respective outer pins 19 engage with each other to cause the

curved plates

17 and 18 to rotate. Yes.

The motion conversion mechanism 20 is a mechanism that transmits the rotational motion of the

curved plates

17 and 18 to the output member 4. The motion conversion mechanism 20 includes a plurality of inner pins 22 provided in the output member 4 and through holes provided in the

curved plates

17 and 18. The plurality of inner pins 22 are arranged at equal intervals in the circumferential direction around the rotation axis of the output member 4. Counterweights 21 and 21 are provided at axial positions adjacent to the

eccentric portions

15 and 16 of the input shaft 3 of the speed reducer 2, respectively.

The wheel bearing 5 includes an outer member 23 having a double-row raceway surface formed on the inner periphery, an inner member 24 having a raceway surface facing the respective raceway surfaces on the outer periphery, and the outer member 23 and the inner member. And the double row rolling elements 25 interposed between the raceway surfaces of the side members 24. The inner member 24 also serves as a hub for mounting the drive wheel. The wheel bearing 5 is a double-row angular ball bearing, and the rolling elements 25 are formed of balls and are held by a cage for each row. The outer member 23 is a stationary raceway and has a flange attached to the end of the reducer housing 7 on the outboard side.

Lubricating oil supply means Jk is an axial oil supply mechanism that supplies lubricating oil used for both the lubrication of the speed reducer 2 and the cooling of the electric motor 1. The lubricating oil supply means Jk includes a lubricating oil passage 30, a motor rotation shaft oil passage 32, a reduction gear oil passage 31, and a pump 28. The lubricating oil passage 30 is provided in the motor housing 8, and the motor rotation shaft oil passage 32 is provided along the axis within the motor rotation shaft 6 of the electric motor 1 and communicates with the lubricating oil passage 30. The speed reducer oil path 31 is provided in the speed reducer 2 and communicates with the motor rotation shaft oil path 32 and the lubricating oil reservoir 29 to supply the lubricating oil to the speed reducer 2.

The reduction gear oil passage 31 has an input shaft oil passage 36, an oil supply port 37, and an oil discharge port 38. The input shaft oil passage 36 communicates with the motor rotation shaft oil passage 32 and extends in the axial direction from the inboard side end inside the input shaft 3 to the outboard side. The oil supply port 37 extends radially outward from the axial position where the

eccentric portions

15 and 16 are provided in the input shaft oil passage 36. The reduction gear housing 7 is provided with an oil discharge port 38 for discharging the lubricating oil used for lubricating the reduction gear 2 to the lubricating oil reservoir 29.

The pump 28 sucks up the lubricating oil stored in the lubricating oil reservoir 29 from the suction port 29b in the lubricating oil reservoir 29 and passes through the lubricating oil passage 30 to the motor rotation shaft oil passage 32 and the speed reducer oil passage 31. To circulate. The pump 28 has, for example, an inner rotor (not shown) that rotates by rotation of the output member 4, an outer rotor that rotates following rotation of the inner rotor, a pump chamber, a suction port, and a discharge port. It is a cycloid pump. When the inner rotor is rotated by the rotation of the inner member 24, the outer rotor is driven to rotate. At this time, the inner rotor and the outer rotor rotate about different rotation centers, so that the volume of the pump chamber changes continuously.

Thereby, the lubricating oil stored in the lubricating oil storage unit 29 is sucked up, flows in from the suction port, and is pumped to the lubricating oil flow path 30 from the discharge port. The lubricating oil is guided from the lubricating oil passage 30 to the motor rotation shaft oil passage 32. A part of the lubricating oil is led from the motor rotation shaft oil passage 32 to the annular gap δ1 through the through hole 6b of the motor rotation shaft 6 to be used for cooling the electric motor 1. The lubricating oil used for this cooling is discharged from the slit between the flange of the rotor fixing member 13 and both end faces of the motor rotor 10, moves downward by centrifugal force and gravity, and falls to the lower part of the motor housing 8. Thereafter, the oil is stored in the lubricating oil reservoir 29 that communicates with the lower portion of the motor housing 8.

The lubricating oil introduced from the motor rotation shaft oil passage 32 to the oil supply port 37 lubricates the inside of the speed reducer 2. That is, the centrifugal force acts on the lubricating oil discharged from the outer diameter side opening end of the oil supply port 37, so that the lubricating oil lubricates each part in the speed reducer 2 while radially outside the speed reducer housing 7. Move towards. Thereafter, the lubricating oil moves downward due to gravity and is stored in the lubricating oil reservoir 29 from the oil discharge port 38.

FIG. 2 is an enlarged cross-sectional view of the lubricating oil reservoir of this in-wheel motor drive device. As shown in the figure, the lubricating oil reservoir 29 is a so-called oil tank provided in the lower part of the speed reducer housing 7. When the vehicle is stopped, the lubricating oil reservoir 29 is filled with the lubricating oil in a full state (initial oil amount height indicated by an arrow). The bottom 29a of the lubricating oil reservoir 29 is provided in a mortar shape having a smaller diameter as it goes downward, and a drain plug 39 and an oil amount detection sensor 40 are provided at the bottom of the mortar-shaped bottom 29a. In this example, an oil amount detection sensor 40 for detecting the oil amount of the lubricating oil is fitted into the tip end portion of the drain plug 39 exposed in the lubricating oil reservoir 29.

As the oil amount detection sensor 40, a pressure sensor or a weight sensor is applied. Among these, the pressure sensor includes, for example, at least one of a diaphragm, a bellows, a capacitive pressure sensor, a semiconductor pressure sensor, and a piezoelectric pressure sensor. However, it is not limited to these sensors. The diaphragm is a thin disk with a fixed outer peripheral edge, and lubricating oil acts on the disk. Accordingly, the disk is elastically deformed in proportion to the pressure difference between the one surface and the other surface of the disk, and the pressure can be detected from the magnitude of the deformation. When the disk is relatively elastically deformed, the pressure can be converted into an electric signal using various displacement sensors. When the elastic deformation of the disk is slight, the magnitude of the disk distortion can be detected by, for example, a strain gauge, and the pressure can be converted into an electric signal. The relationship between the oil amount and the pressure of the lubricating oil is stored in, for example, a table to be described later, and the calculation means 41 (FIG. 3) calculates the oil amount by comparing the detected pressure with the table (the same applies hereinafter). ).

The bellows includes a thin cylindrical portion provided with a bellows-like pleat around the cylindrical portion, and the cylindrical portion expands and contracts in the axial direction according to a pressure difference between the inside and the outside of the cylindrical portion. The end surface of the cylindrical portion is displaced by the expansion and contraction of the cylindrical portion. The amount of displacement of this end face is proportional to the pressure difference. The displacement amount can be converted into an electric signal by a displacement sensor or the like. The capacitive pressure sensor utilizes the fact that the diaphragm or the bellows is elastically deformed by pressure. That is, the movable plate is displaced with respect to the fixed plate, and the pressure is electrically detected by utilizing the change in capacitance between the plates.

The semiconductor pressure sensor is an integrated diaphragm and strain gauge, and a pressure receiving diaphragm is formed of a silicon single crystal, and a strain gauge is formed by diffusing impurities in a part of the pressure receiving diaphragm. When pressure is applied to the pressure receiving diaphragm, a part of the pressure receiving diaphragm is deformed to change the resistance of the strain gauge, and an electric signal proportional to the pressure is obtained by the bridge circuit. The piezoelectric pressure sensor can convert a pressure change into an electric signal by applying pressure to the piezoelectric element and amplifying a voltage generated by the piezoelectric effect. As the weight sensor, for example, a load cell that measures the weight proportional to the amount of lubricating oil in the lubricating oil reservoir 29 by the strain of the elastic body, or a magnetostrictive force sensor that magnetically detects the weight can be applied. As shown in FIG. 4, the relationship between the amount and weight of lubricating oil is stored in, for example, a table 41a (FIG. 3), and the calculation means 41 (FIG. 3) illuminates the detected weight against the table. Calculate the oil amount.

The control system will be described with reference to FIG. FIG. 3 is a block diagram of a control system of the in-wheel motor drive device. As shown in the figure, the control device includes a VCU 42 that is an electric control unit that controls the entire automobile, and an inverter device 43 that controls the drive motor 1 in accordance with a command from the VCU 42. The VCU 42 and the inverter device 43 are mounted on the vehicle body. The VCU 42 includes a computer, a program executed on the computer, various electronic circuits, and the like.

The inverter device 43 includes a power circuit unit 44 provided for each electric motor 1 and a motor control unit 45 (motor control device) that controls the power circuit unit 44. The motor control unit 45 may be provided in common for each power circuit unit 44 or may be provided separately. The motor control unit 45 has a function of outputting information such as detection values and control values relating to the in-wheel motor drive device of the motor control unit 45 to the VCU 42.

The power circuit unit 44 includes an inverter 47 that converts the DC power of the battery 46 into three-phase AC power that is used to drive the electric motor 1, and a PWM driver 48 that controls the inverter 47. The inverter 47 is composed of a plurality of semiconductor switching elements (not shown), and the PWM driver 48 performs pulse width modulation on the input current command and gives an on / off command to each of the semiconductor switching elements.

The motor control unit 45 includes a computer, a program executed on the computer, and an electronic circuit, and has a motor drive control unit 49 as a basic control unit. The motor drive control unit 49 is a unit that converts the current command into a current command in accordance with an acceleration / deceleration command by a torque command or the like given from the VCU 42 that is a host control unit, and gives a current command to the PWM driver 48 of the power circuit unit 44. The motor drive control unit 49 obtains a motor current value to be passed from the inverter 47 to the electric motor 1 from the current detection unit 35 and performs current feedback control. The motor drive control unit 49 obtains the rotation angle of the motor rotor 10 (FIG. 1) of the electric motor 1 from the angle sensor 50 and performs control according to the rotation angle such as vector control.

In this embodiment, the motor control unit 45 configured as described above is provided with the calculation means 41, the determination unit 51, the abnormality control means 52, and the abnormality report means 53, and the VCU 42 is provided with the abnormality display means 54. The in-wheel motor drive device includes these calculation means 41, determination unit 51, abnormality control means 52, abnormality report means 53, and abnormality display means 54. The oil amount detection sensor 40 is connected to the calculation means 41 via a signal line L1. The signal line L1 is disposed coaxially with the connection cable L2 of the angle sensor 50. A connecting portion Cn such as a connector or a terminal block is provided in the middle in the longitudinal direction of the signal line L1 connecting the oil amount detection sensor 40 and the calculating means 41.

The computing means 41 computes the amount of lubricating oil when the vehicle is powered on, while the detected value is illuminated against the table 41a for a certain period of time after the vehicle is stopped. The above-mentioned “when the vehicle is turned on when the vehicle is turned on” refers to a state where the VCU 42 of the electric vehicle is turned on and the vehicle is completely stopped. For example, (1) a driver or the like When the VCU 42 is turned on by operating the starting means such as the key and the start button from the “OFF” position to the “accessory power supply” position before supplying power to the electric motor 1, or (2) the VCU 42 is powered on. Is turned on to turn on the starting means, but the VCU 42 does not generate an acceleration command to the electric motor 1. When the vehicle is in operation, the lubricating oil is circulated and the sensor output of the oil amount detection sensor 40 is not stable. Therefore, the measurement by the oil amount detection sensor 40 is performed after the vehicle stops.

The determination unit 51 determines whether or not the oil amount calculated by the calculation means 41 is out of the set range. The setting range in this case is appropriately determined by experiment, simulation, or the like. For example, from an experimental result or the like, an oil amount of a minimum level or more that does not cause excessive wear in each part of the speed reducer 2 can be determined as the “set range”. When the determination unit 51 determines that the oil amount is out of the set range, that is, less than the minimum level, the abnormality control unit 52 outputs a signal indicating that the oil amount is out of the set range (abnormal). Control in response to. The setting range can be arbitrarily rewritten. When the oil amount is not outside the set range, a signal indicating that the oil amount is normal is input to the motor drive control unit 49 from the normal time control means 55. In this case, the motor drive control unit 49 performs the above-described control.

In response to the output of the signal indicating that the oil amount is out of the set range, the abnormal time control means 52 outputs, for example, information indicating that the lubricating oil supply means Jk (FIG. 1) is abnormal. Alternatively, a command for limiting the output of the electric motor 1 is input to the motor drive control unit 49. The motor drive control unit 49 limits the motor torque and the number of rotations of the electric motor 1 based on a command from the abnormality control unit 52 as an output limiting unit. As a specific example of output restriction, the motor drive control unit 49 gradually decreases the motor torque of the electric motor 1 to stop driving the electric motor 1, for example. Further, in a state where a command for limiting the output of the electric motor 1 is input to the motor drive control unit 49, the rotation start of the electric motor 1 is not permitted.

The abnormality reporting unit 53 receives the information from the abnormality control unit 52 and outputs the abnormality occurrence information to the VCU 42. The abnormality display means 54 of the VCU 42 alerts the driver by causing the display device to display information indicating that the lubricating oil supply means Jk (FIG. 1) is abnormal.

The effect will be described with reference to FIG. Lubricating oil is temporarily stored in the lubricating oil storage unit 29. During the operation of the vehicle, the pump 28 sucks up the lubricating oil stored in the lubricating oil reservoir 29 and forcibly circulates it through the lubricating oil passage 30 to the motor rotation shaft oil passage 32 and the reduction gear oil passage 31. . A part of the lubricating oil is sequentially led from the motor rotation shaft oil passage 32 to the through hole 6b and the annular gap δ1 to be used for cooling the electric motor 1. The lubricating oil supplied for cooling is stored in the lubricating oil reservoir 29 through the lower part of the motor housing 8. The lubricating oil introduced from the motor rotation shaft oil passage 32 to the oil supply port 37 moves radially outward in the speed reducer housing 8 while lubricating each part in the speed reducer 2 by the action of centrifugal force. Thereafter, the lubricating oil moves downward due to gravity and is stored in the lubricating oil reservoir 29 from the oil discharge port 38.

When the amount of oil detected by the oil amount detection sensor 40 deviates from a predetermined setting range when the vehicle is stopped when the vehicle is powered on, the abnormal time control means 52 (FIG. 3) generates a signal indicating abnormality. In response, information indicating that the lubricating oil supply means Jk is abnormal is output, and a command for limiting the output of the electric motor 1 is input to the motor drive control unit 49 (FIG. 3).

Since the oil amount detection sensor 40 is provided at the lowermost part of the lubricating oil reservoir 29, the oil amount can be detected accurately and easily even if the oil amount is excessively reduced. In this way, when the oil amount is excessively reduced, the driver recognizes the fact from the abnormality information output from the abnormality reporting means 53 and, for example, pulls the vehicle by a tow truck or the like and moves it to a repair shop or the like. The necessary measures can be taken. Thereby, abnormalities, such as excessive wear of the reduction gear 2, can be prevented beforehand. Further, the oil amount detection sensor 40 is fitted into the tip end portion of the drain plug 39 at the lowermost portion of the lubricating oil reservoir 29. As described above, the oil amount detection sensor 40 can be easily provided at the lowermost portion of the lubricating oil reservoir 29, so that the in-wheel motor drive device can be made compact and the unsprung weight can be reduced while improving versatility. .

When the float type oil amount detection mechanism is provided in the storage unit, the volume of the storage unit needs to be increased. In this embodiment, the calculation means 41 displays the detection value detected by the pressure sensor or the weight sensor in the table 41a. Calculate the oil quantity in light of Accordingly, it is not necessary to store a relatively large mechanism such as a float type oil amount detection mechanism in the lubricating oil reservoir, and the apparatus can be prevented from being enlarged. In addition, the amount of lubricating oil in the lubricating oil reservoir 29 can be easily detected.

Also, a shaft center oil supply mechanism (lubricant supply means Jk) is provided, and the lubricant is forcibly circulated to the motor rotation shaft oil passage 32 and the speed reducer oil passage 31 via the lubricant oil passage 30 by the pump 28. Thus, the lubricating oil can be stably supplied over the entire speed reducer. The lubricating oil reservoir 29 has a mortar-shaped bottom 29a, and the oil amount detection sensor 40 is provided at the bottom of the mortar-shaped bottom 29a. Therefore, the lubricating oil stored in the lubricating oil reservoir 29 is The oil flows into the bottom of the mortar-shaped bottom 29a due to the weight of the oil. For this reason, the amount of lubricating oil can be detected stably.

The motor drive control unit 49 shown in FIG. 3 limits the motor torque and the rotational speed of the electric motor 1 based on the command from the abnormal time control means 52, thereby preventing the lubricating oil from being insufficiently supplied. In addition, it is possible to prevent abnormalities such as excessive wear from occurring in the speed reducer 2 and the like. In this case, the motor drive control unit 49 gradually decreases the motor torque of the electric motor 1 and stops driving the electric motor 1. By forcibly limiting the output of the electric motor 1 in this manner, excessive wear and abnormal heat generation of the speed reducer 2 can be reliably prevented. Therefore, the abnormality of the in-wheel motor drive device due to excessive reduction of the lubricating oil can be prevented in advance, and the sudden stop while the vehicle is running can be prevented.

A modification will be described. Instead of the calculation means 41 shown in FIG. 3, a calculation means 41A having the table may be provided in the VCU 42, and the calculation means 41A and the oil amount detection sensor 40 may be connected by a signal line L3 indicated by a two-dot chain line. In that case, the output of the calculation means 41 </ b> A is input to the determination unit 51 of the motor control unit 45. The calculating means 41 or 41A may measure the oil amount of the lubricating oil in the lubricating oil reservoir 29 a plurality of times by the oil amount detecting sensor 40 after the vehicle stops, and calculate an average value thereof. good. In this case, the amount of lubricating oil can be determined stably. You may provide the oil amount detection sensor 40 in all the in-wheel motor drive devices mounted in a vehicle, respectively. An audio output unit that receives the abnormality information output from the abnormality report unit 53 and outputs a sound may be provided.

FIG. 5 is a diagram schematically showing an electric vehicle equipped with an in-wheel motor drive device. This electric vehicle is a four-wheeled vehicle in which the wheels 56 that are the left and right rear wheels of the vehicle body are drive wheels, and the wheels 57 that are the left and right front wheels are driven wheels. The front wheel 57 is a steering wheel. The electric vehicle of this example includes drive units that drive the left and

right wheels

56 and 56 serving as drive wheels by independent

electric motors

1 and 1, respectively. The rotation of the electric motor 1 is transmitted to the wheel 56 via the speed reducer 2 and the wheel bearing 5. The drive unit constitutes an in-wheel motor drive device including the electric motor 1, the speed reducer 2, and the wheel bearing 5, in which part or the whole of the electric motor 1 is disposed in the wheel 56. Since the in-wheel motor drive device according to any one of the above-described embodiments is mounted on this electric vehicle, it is possible to prevent an abnormality of the in-wheel motor drive device due to excessive reduction of lubricating oil, and to stop suddenly while the vehicle is running Can be prevented from triggering.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily assume various changes and modifications within the obvious scope by looking at the present specification. Accordingly, such changes and modifications are to be construed as within the scope of the invention as defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Reduction gear 5 ... Wheel bearing 28 ... Pump 29 ... Lubricating oil storage part 29a ... Bottom part 30 ... Lubricating oil flow path 31 ... Reduction gear oil path 32 ... Motor rotating shaft oil path 40 ... Oil quantity detection sensor 53 ... Abnormality reporting means 56 ... Wheel Jk ... Lubricating oil supply means

Claims

An in-wheel motor drive device comprising: an electric motor that drives a wheel; a wheel bearing that supports the wheel; and a speed reducer that decelerates the rotation of the electric motor and transmits the reduced speed to the wheel bearing;
A lubricating oil reservoir for storing lubricating oil;
Lubricating oil supply means for supplying the lubricating oil stored in the lubricating oil storage unit back to the reduction gear; and
An oil amount detection sensor that is provided at the lowermost portion of the lubricating oil reservoir and detects the amount of lubricating oil;
The in-wheel motor drive device which provided.
2. The in-wheel motor drive device according to claim 1, wherein the oil amount detection sensor is a pressure sensor or a weight sensor.
The in-wheel motor drive device according to claim 1 or 2, wherein the lubricating oil supply means includes:
A lubricating oil passage provided in a motor housing of the electric motor;
A motor rotation shaft oil passage provided along an axis in a motor rotation shaft of the electric motor and communicating with the lubricating oil passage;
A speed reducer oil path provided in the speed reducer and communicating with the motor rotation shaft oil path and the lubricating oil reservoir and supplying lubricating oil to the speed reducer;
A pump that sucks up the lubricating oil stored in the lubricating oil reservoir and circulates it through the lubricating oil flow path to the motor rotation shaft flow path and the speed reducer oil path;
An in-wheel motor drive device which is an axial oil supply mechanism having
The in-wheel motor drive device according to any one of claims 1 to 3, wherein the lubricating oil storage portion has a mortar-shaped bottom portion, and the oil amount detection is provided at a lowermost portion of the mortar-shaped bottom portion. An in-wheel motor drive device provided with a sensor.
5. The in-wheel motor drive device according to claim 1, wherein an oil amount detected by the oil amount detection sensor is determined when the vehicle is stopped while the vehicle is powered on. An in-wheel motor drive device provided with an abnormality report means for outputting abnormality information of the lubricating oil supply means when out of a set range.