JP6545575B2 - In-wheel motor drive - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an in-wheel motor drive device, and more particularly to a technology for determining the oil level of lubricating oil using a plurality of coil temperature detection means.

Various techniques for detecting the oil level of lubricating oil in vehicles have been proposed.
(1) Abnormality detection device for fueling device of internal combustion engine (Patent Document 1)
In this abnormality detection device, a first sensor that outputs a signal at a first height or more and a second sensor that outputs a signal when the oil level is a second height different from the first height are output. And an abnormality determination unit that determines that the combination of the output levels of the first and second sensors is abnormal when the combination of the output levels of the first and second sensors can not normally occur.

(2) Lubricant oil consumption measuring device for internal combustion engine (Patent Document 2)
In this lubricating oil consumption measuring device, a sub tank having a sub tank forming a pillar of lubricating oil having an oil level substantially equal to that of the lubricating oil in the crankcase, and a sub tank having a reflective surface reflecting light on the upper surface The floating float floats on the oil surface of the lubricating oil inside, and the laser light is emitted above the float and emits laser light downward, and the laser light reflected by the reflection surface of the float is taken in, and the distance to the float is the oil surface And an oil level detection unit for detecting a level.

(3) Wheel drive device (Patent Document 3)
In this wheel drive device, in order to make the temperature detection means of the motor coil less susceptible to the influence of the lubricating oil, it is proposed to be disposed above the motor central axis and between the coils adjacent in the circumferential direction. ing.

Patent No. 2884627 Patent No. 3205173 JP, 2015-63266, A

In the prior art of (1), it is necessary to judge the liquid level of the amount of lubricating oil in the oil pan of a normal engine with two different types of sensors (water temperature sensor and liquid level sensor). Therefore, the structure is complicated and expensive.
In the prior art of (2), the oil level of the lubricating oil is directly measured. However, since a configuration capable of emitting and receiving laser light is required, the apparatus becomes large and the cost becomes high.
In the prior art of (3), in order to make it hard to receive the influence of lubricating oil, it is proposed about the arrangement place of one motor coil temperature detecting means, but the oil level height and lubricating oil level of lubricating oil from the one motor coil temperature detecting means It is not possible to determine an abnormality in the oil level.

  An object of the present invention is to provide an in-wheel motor drive device capable of determining an abnormality in the oil level of lubricating oil and achieving downsizing of the device and cost reduction.

In the in-wheel motor drive device according to the present invention, an electric motor 1 for driving a wheel, a wheel bearing 5 for rotatably supporting the wheel, and a reduction gear for reducing the rotation of the electric motor 1 and transmitting it to the wheel bearing 5 In wheel equipped with a motor 2, a lubricating oil supply mechanism Jk for supplying lubricating oil used for both the lubrication of the reduction gear 2 and the cooling of the electric motor 1, and a control device 44 for controlling the electric motor 1 In the motor drive,
The lubricating oil supply mechanism Jk includes an in-motor lubricating oil reservoir 31 for sealing the lubricating oil to be supplied to the electric motor 1 at an oil level defined in the electric motor 1. The first coil temperature detection means Sa for detecting the temperature of the motor coil 78 not immersed in the lubricating oil and the second coil temperature detection means Sb for detecting the temperature of the motor coil 78 immersed in the lubricating oil Provided
The control device 44 is configured such that the lubricating oil in the electric motor 1 is sealed at the determined oil level based on the temperatures detected by the first and second coil temperature detection means Sa and Sb, respectively. It is characterized in that it has determination means 41 for determining whether or not it is present.
The defined oil level is determined by the result of a test, a simulation, or the like.

  According to this configuration, the first coil temperature detection means Sa detects the temperature of the motor coil 78 not immersed in the lubricating oil at the start of the vehicle or the like, and the second coil temperature detection means Sb is immersed in the lubricating oil The temperature of the motor coil 78 is detected. The judging means 41 determines the oil level at which the lubricating oil to be sealed in the in-motor lubricating oil reservoir 31 is determined based on the temperatures detected by the first and second coil temperature detecting means Sa and Sb respectively. To determine if it is enclosed.

  For example, a constant current is supplied from the control device 44 to the electric motor 1, and the temperature rise degree detected by the first coil temperature detection means Sa and the temperature rise detected by the second coil temperature detection means Sb By comparing the degree with the degree, it is determined whether the lubricating oil is sealed at a predetermined oil level. This is because, in the case where each motor coil 78 has the same calorific value, the first coil temperature detection means Sa, the periphery of which is not filled with lubricating oil, reacts hypersensitively to the heat generation of the motor coil 78. In the second coil temperature detection means Sb whose periphery is filled with lubricating oil, the heat generation of the motor coil 78 transfers heat to the surrounding lubricating oil by heat transfer and heat conduction, and the periphery is filled with lubricating oil The temperature of the motor coil 78 is hard to rise. For this reason, it utilizes that the temperature rise degree with respect to time of coil temperature detection means Sa and Sb differs.

  The coil temperature detection means Sa, Sb can be obtained inexpensively and easily from commercially available products etc. The first coil temperature detection means Sa whose periphery is not filled with lubricating oil detects an overload of the electric motor 1 originally It is often provided to By adding a second coil temperature detection means Sb whose periphery is filled with lubricating oil to the configuration provided with such a first coil temperature detection means Sa, the judgment means 41 compares the degree of increase in these temperatures It can be used for the judgment. Therefore, the apparatus can be miniaturized and the cost can be reduced as compared with the prior art or the like which requires a space for emitting and receiving laser light.

  The first coil temperature detection means Sa is disposed above the central axis L1 of the electric motor 1, and the second coil temperature detection means Sb is disposed below the central axis L1. As well. In this case, the first coil temperature detection means Sa is less susceptible to the influence of lubricating oil, and can detect the heat generation of the motor coil 78 to be detected with high sensitivity. In the second coil temperature detecting means Sb, heat generation of the motor coil 78 to be detected is transferred to the surrounding lubricating oil by heat transfer and heat conduction, and the temperature of the motor coil 78 is made more difficult to rise. Can.

A vehicle speed detection means Sd for detecting the vehicle speed is provided, and the determination means 41 is determined when the vehicle is started, or when the vehicle speed detected by the vehicle speed detection means Sd is less than a predetermined fixed value, or after the vehicle is stopped. The determination may be performed after the elapsed time has passed.
The predetermined time or less is determined by the result of the test, the simulation, or the like.

  Immediately after the operation of the vehicle, the oil level of the lubricating oil is stored in the lubricating flow passage, adheres to the wall surface in the in-wheel motor drive device, etc., and the oil level of the lubricating oil before the start of the operation of the vehicle There is a difference in the oil level of the lubricating oil immediately after operation. Therefore, it is desirable that the determination unit 41 make the determination after a predetermined time has elapsed after the drive stop of the vehicle or immediately before the drive of the vehicle. Alternatively, it may be determined as one of the abnormality check items at the time of vehicle start of the entire vehicle, which is performed when the start switch of the vehicle is input. As described above, by performing the determination by the determination means 41 at the timing when the difference in the oil level height hardly occurs, it is possible to always obtain the stable determination result.

  The control device 44 outputs abnormality occurrence information to the upper control means 43 of the control device 44 when it is determined by the determination means 41 that the lubricating oil is not enclosed at the defined oil level height. The abnormality reporting means 50 may be included. When the abnormality reporting means 50 outputs the abnormality occurrence information to the upper control means 43, the driver of the vehicle can be alerted to take action such as moving the vehicle to a repair shop or the like at an early stage.

The control device 44 has abnormal time control means 49 for limiting the current of the electric motor 1 when it is determined by the determination means 41 that lubricating oil is not enclosed at the defined oil level height. As well.
Limiting the current also includes zeroing the current.
In this case, when the abnormality control means 49 limits the current of the electric motor 1, it is possible to prevent an overload of the electric motor 1 and to prevent the reduction gear 2 from becoming a lubrication failure in advance. .

  The in-wheel motor drive device according to the present invention comprises an electric motor for driving a wheel, a wheel bearing for rotatably supporting the wheel, and a reduction gear for reducing the rotation of the electric motor and transmitting it to the wheel bearing. An in-wheel motor drive system comprising: a lubricating oil supply mechanism for supplying lubricating oil used for both lubrication of a reduction gear and cooling of the electric motor; and a control device for controlling the electric motor, wherein the lubricating oil supply mechanism The motor coil further includes an in-motor lubricating oil storage portion for sealing the lubricating oil supplied to the electric motor at an oil level defined in the electric motor, and a motor coil not immersed in the lubricating oil in the electric motor. A first coil temperature detecting means for detecting the temperature of the motor, and a second coil temperature detecting means for detecting the temperature of the motor coil immersed in the lubricating oil; The apparatus determines, based on the temperatures respectively detected by the first and second coil temperature detecting means, whether or not the lubricating oil in the electric motor is enclosed at the predetermined oil level height. It has a judgment means. For this reason, while being able to determine the abnormality of the oil level height of lubricating oil, size reduction of an apparatus can be achieved and cost reduction can be achieved.

It is a sectional view of an in-wheel motor drive concerning an embodiment of this invention. FIG. 2 is a cross-sectional view of a reduction gear portion taken along line II-II in FIG. It is the elements on larger scale of FIG. It is sectional drawing of the motor part used as the IV-IV line cross section of FIG. It is the elements on larger scale which expand and show the A section of FIG. It is a block diagram of the control system of the in-wheel motor drive device. It is a figure which shows the example of temperature change by the 1st and 2nd coil temperature detection means of the in-wheel motor drive device of the same. It is sectional drawing of the motor part of the in-wheel motor drive device which concerns on other embodiment of this invention. It is sectional drawing of the motor part of the in-wheel motor drive device based on further another embodiment of this invention. It is sectional drawing of the motor part of the in-wheel motor drive device based on further another embodiment of this invention. It is sectional drawing of the motor part of the in-wheel motor drive device based on further another embodiment of this invention. It is a figure which shows schematic structure of the vehicle carrying the same in-wheel motor drive device.

  An in-wheel motor drive device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7. As shown in FIG. 1, the in-wheel motor drive device includes an electric motor 1 for driving wheels, a reduction gear 2 for reducing the rotation of the electric motor 1, and an input shaft 3 of the reduction gear 2 (reduction gear input And a wheel bearing 5 rotated by an output member 4 coaxial with the shaft 3). The electric motor 1, the reduction gear 2, and the bearing 5 for a wheel constitute an in-wheel motor drive which is an assembly part with each other, and the in-wheel motor drive is partially or entirely disposed in the wheel Ru. The in-wheel motor drive further includes a lubricant oil supply mechanism Jk and a control device 44 (FIG. 6).

A reduction gear 2 is interposed between the wheel bearing 5 and the electric motor 1, and a hub (not shown) of a wheel which is a driving wheel supported by the wheel bearing 5, a motor rotation shaft 6 of the electric motor 1, and a reduction gear. The machine input shaft 3 and the output member 4 are connected coaxially.
A suspension (not shown) of the vehicle is connected to a reduction gear housing 7 that houses the reduction gear 2. In this specification, when the motor drive device is provided in a vehicle, the side that is closer to the outside in the vehicle width direction of the vehicle is called the outboard side, and the side that is closer to the center in the vehicle width direction is the inboard side Call.

  The electric motor 1 is an IPM motor (so-called embedded magnet 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 a motor rotation shaft 6. The motor housing 8 is provided with bearings 11 and 12 separated in the axial direction, and the motor rotation shaft 6 is rotatably supported by these bearings 11 and 12.

  The motor rotation shaft 6 transmits the driving force of the electric motor 1 to the reduction gear 2. A radially outwardly extending flange portion 6 a is provided in the vicinity of the axially middle portion of the motor rotation shaft 6. The rotor fixing member 13 is provided on the flange portion 6 a, and the motor rotor 10 is attached to the rotor fixing member 13.

  One end of the reduction gear input shaft 3 in the axial direction extends into the motor rotation shaft 6 and is spline-fitted to the motor rotation shaft 6. The bearing 14 a is fitted in the cup portion 4 a of the output member 4, and the bearing 14 b is fitted in the cylindrical connecting member 26 connected to the cup portion 4 a via the inner pin 22. An integral shaft of the reduction gear input shaft 3 and the motor rotation shaft 6 is rotatably supported by bearings 14 a, 14 b, 11, 12. Eccentric portions 15 and 16 are provided on the outer peripheral surface of the reduction gear input shaft 3 in the reduction gear housing 7. These eccentric parts 15 and 16 are provided 180 degrees out of phase so that the centrifugal force by eccentric movement may mutually negate.

The reduction gear 2 is a cycloid reduction gear having an outer pin housing Ih, a reduction gear input shaft 3, curved plates 17 and 18, a plurality of outer pins 19, an inner pin 22, and a counterweight 21.
FIG. 2 is a cross-sectional view of the reduction gear portion taken along line II-II in FIG. In the reduction gear 2, two curved plates 17 and 18 each formed of a smooth wavelike trochoid curve having a smooth outer shape are attached to the eccentric portions 15 and 16 via the bearings 85 respectively. A plurality of outer pins 19 for guiding the eccentric movement of the curved plates 17 and 18 on the outer peripheral side are respectively provided on the outer pin housing Ih (FIG. 1) inside the reduction gear housing 7 and attached to the cup portion 4a (FIG. 1) The plurality of inner pins 22 are engaged with the plurality of circular through holes 89 provided in the interiors of the curved plates 17 and 18 in an inserted state.

  Needle bearings 92, 93 are mounted on the outer pins 19 and the inner pins 22, respectively, as shown enlarged in FIG. Each outer pin 19 is supported at its both ends by needle roller bearings 92 and is in rolling contact with the outer peripheral surface of each curved plate 17, 18. In each inner pin 22, the outer ring 93 a of the needle roller bearing 93 is in rolling contact with the inner periphery of each through hole 89. Needle roller bearings 92 and 93 reduce the contact resistance with the outer periphery of each curved plate 17 and 18, and the contact resistance with each inner pin 22 and the inner periphery of each through hole 89, respectively. The outer ring 93a of the needle roller bearing 92 is fitted and fixed to the outer pin housing Ih.

  Therefore, as shown in FIG. 1, the eccentric movement of the curved plates 17 and 18 can be smoothly transmitted to the inward member 5 a of the wheel bearing 5 as rotational movement. When the motor rotation shaft 6 rotates, the curved plates 17 and 18 provided on the outer periphery of the eccentric portions 15 and 16 of the reduction gear input shaft 3 that rotates integrally with the motor rotation shaft 6 perform eccentric movement. At this time, the outer pin 19 is engaged in rolling contact with the outer peripheral surface of each of the curved plates 17 and 18 in an eccentric movement. At the same time, only the rotational movement of each of the curved plates 17, 18 is rotated relative to the output member 4 and the inner member 5a by the engagement of the inner pin 22 with the through hole 89 (FIG. 3). It is transmitted as The rotation of the inward member 5 a is decelerated relative to the rotation of the motor rotation shaft 6.

  The lubricating oil supply mechanism Jk is an axial center oiling mechanism that supplies lubricating oil used for both the lubrication of the reduction gear 2 and the cooling of the electric motor 1 from the inside of the motor rotation shaft 6. The lubricating oil supply mechanism Jk has a lubricating oil passage 29, an oil supply passage 30, an in-motor lubricating oil storage portion 31, a discharge oil passage 38, and a pump 28. The lubricating oil passage 29 is an oil passage in the reduction gear housing 7 of the reduction gear 2, and the lubricating oil passage 29 includes a lubricating oil tank 29a. The lubricating oil tank 29 a is provided in the lower part of the reduction gear housing 7 and stores lubricating oil, and communicates with the in-motor lubricating oil storage part 31 provided in the lower part of the motor housing 8.

  The supply oil passage 30 is an oil passage that supplies lubricating oil to the electric motor 1 and the reduction gear 2 from the lubricating oil tank 29a. The supply oil passage 30 includes a suction side oil passage 30a, a discharge side oil passage 30b, a housing outer peripheral side oil passage 30c, a communication passage 30d, a motor rotation shaft oil passage 30e, and a reduction gear oil passage 30f. The suction side oil passage 30 a communicates with the suction port in the lubricating oil tank 29 a and the suction port of the pump 28, and is configured by the lower portion of the reduction gear housing 7 and the lower portion of the motor housing 8. The discharge side oil passage 30 b communicates with the discharge port of the pump 28 and extends substantially radially outward in the motor housing 8.

  The housing outer peripheral side oil passage 30 c communicates with the discharge side oil passage 30 b and extends in the axial direction from the outboard side to the inboard side in the motor housing 8. The communication passage 30d is formed at the inboard end of the motor housing 8. The inlet of the communication passage 30d communicates with the outer peripheral oil passage 30c, and the outlet of the communication passage 30d is connected to the motor rotation shaft oil passage 30e. It communicates.

  The motor rotation shaft oil passage 30 e is provided along the axial center in the motor rotation shaft 6. A part of the lubricating oil led from the communication passage 30d to the motor rotary shaft oil passage 30e is formed inside the rotor fixing member 13 via a radially outward extending through hole of the motor rotary shaft 6 and the flange portion 6a. The motor rotor 10 is cooled by passing through the radially outward extending oil passage. Further, the motor coil 78 is cooled by injecting lubricating oil from the oil outlet of the oil passage to the inner peripheral surface of each coil end 78a by the centrifugal force of the motor rotor 10 and the pressure of the pump 28.

The reducer oil passage 30 f is provided in the reducer 2 and supplies lubricating oil to the reducer 2. The reducer oil passage 30 f has an input shaft oil passage 36 and an oil supply port 37. The input shaft oil passage 36 communicates with the motor rotation shaft oil passage 30 e and axially extends from the inboard end of the reduction gear input shaft 3 to the outboard side. The oil supply port 37 extends radially outward from an axial position of the input shaft oil passage 36 where the eccentric portions 15 and 16 are provided.
The reduction gear housing 7 is provided with a discharge oil passage 38 for discharging the lubricating oil supplied to the reduction gear 2 to the lubricating oil tank 29a.

  The pump 28 sucks up the lubricating oil stored in the lubricating oil tank 29a from the suction port in the lubricating oil tank 29a via the suction side oil passage 30a and sequentially discharges the oil passage 30b and the oil passage 30c on the housing outer side. The fluid is circulated to the motor rotary shaft oil passage 30e and the reduction gear oil passage 30f via the communication passage 30d. The pump 28 is disposed between the electric motor 1 and the reduction gear 2 coaxially. The pump 28 is, for example, an inner rotor (not shown) rotated by the rotation of the output member 4, an outer rotor driven to rotate with the rotation of the inner rotor, a pump chamber, a suction port, and a discharge port Not shown).

  When the inner rotor is rotated by the rotation of the output member 4 driven by the electric motor 1, the outer rotor is driven to rotate. At this time, the volume of the pump chamber is continuously changed by rotating the inner rotor and the outer rotor about different rotation centers. Thus, the lubricating oil stored in the lubricating oil tank 29a is sucked from the suction port via the suction side oil passage 30a and flows in from the suction port, and the discharge side oil passage 30b from the discharge port, the housing outer peripheral side The oil passage 30c and the communication passage 30d are sequentially pumped.

  The lubricating oil is led from the communication passage 30d to the motor rotary shaft oil passage 30e. After cooling the motor rotor 10 and the motor coil 78 as described above, part of the lubricating oil moves downward by gravity and is stored in the in-motor lubricating oil reservoir 31 and the lubricating oil tank 29a. In this in-wheel motor drive device, the lubricating oil stored and sealed in the in-motor lubricating oil storage portion 31 is adjusted to have a defined oil level H. The determined oil level height H is a height that falls within a certain range between the oil level upper limit and the oil level lower limit. As shown in FIG. 4, the height of the oil surface H is such that the motor coil 78 located on the lowermost side in the vertical direction and the motor coils 78, 78 adjacent to the circumferential direction on the motor coil 78 are immersed in lubricating oil. It is determined by the results of tests and simulations.

  As shown in FIG. 1, the lubricating oil guided from the motor rotation shaft oil passage 30e to the oil supply port 37 via the input shaft oil passage 36 is discharged from the outer diameter side open end of the oil supply port 37. . The centrifugal force and the pressure of the pump 28 act on the lubricating oil so that the lubricating oil moves radially outward in the reduction gear housing 7 while lubricating the components in the reduction gear 2. Thereafter, the lubricating oil moves downward by gravity, and is stored in the lubricating oil tank 29 a from the oil outlet 38.

A coil temperature detection means etc. are demonstrated.
The in-wheel motor drive device is provided with first and second coil temperature detection means Sa, Sb for detecting the temperature of the motor coil 78 of the electric motor 1, and a rotational speed detection sensor Sc described later. The first coil temperature detection means Sa detects the temperature of the motor coil 78 not immersed in the lubricating oil in the electric motor 1. The second coil temperature detection means Sb detects the temperature of the motor coil 78 immersed in the lubricating oil in the electric motor 1. The first and second coil temperature detection means Sa and Sb have the same configuration. For example, a thermistor is used for each coil temperature detection means Sa and Sb.

FIG. 4 is a cross-sectional view of the motor portion taken along line IV-IV in FIG.
The motor rotor 10 of the electric motor 1 has, for example, a core portion (not shown) made of a soft magnetic material and a permanent magnet (not shown) built in the core portion. For example, a neodymium magnet is used for this permanent magnet.

  The motor stator 9 of the electric motor 1 has, for example, a stator core portion 77 made of a soft magnetic material, a motor coil 78, and an insulating member 79. The stator core portion 77 has a ring shape whose outer peripheral surface is circular in cross section, and a plurality of teeth 77 a protruding to the inner diameter side are formed in a row in the circumferential direction on the inner peripheral surface. The motor coil 78 is wound around each tooth 77 a of the stator core portion 77.

  The first coil temperature detection means Sa is disposed above the central axis L1 of the electric motor 1, and the second coil temperature detection means Sb is disposed below the central axis L1. Of the motor coil 78 wound around each tooth 77a, the lubricating oil supply mechanism Jk (FIG. 1) is provided to the coil end 78a (FIG. 1) that protrudes inboard and outboard than the width of the stator core 77 Lubricating oil is injected and sprayed from the

  FIG. 5 is a partially enlarged view showing a portion A of FIG. 4 in an enlarged manner. As shown in FIG. 4 and FIG. 5, the gap .delta. Between the motor coils 78, 78 adjacent to each other in the circumferential direction is made close to the motor coil 78 between the teeth 77a, 77a adjacent to each other in the circumferential direction. The coil temperature detecting means Sa and Sb are disposed. The motor coils 78, 78 adjacent to each other are covered with an insulating member 79 made of an insulating material together with the coil temperature detecting means Sa (Sb).

  As shown in FIG. 1, the rotational speed detection sensor Sc is provided in the motor housing 8 and detects the rotational speed of the electric motor 1. A motor drive control unit 48 (FIG. 6) described later obtains the rotation angle of the motor rotor 10 from the rotation speed detection sensor Sc and performs vector control. As this rotational speed detection sensor Sc, for example, a resolver or a GMR sensor can be applied.

The control system will be described.
FIG. 6 is a block diagram of a control system of this in-wheel motor drive device. The vehicle is provided with an ECU 43 that is an electric control unit that controls the entire vehicle. The control device is an inverter device 44 that controls the traveling electric motor 1 in accordance with a command from the ECU 43, which is an upper control means of the control device. The inverter device 44 has a power circuit unit 45 provided for each of the electric motors 1 and a motor control unit 46 that controls the power circuit unit 45. The motor control unit 46 has a function of outputting, to the ECU 43, pieces of information such as detection values and control values regarding the in-wheel motor drive device possessed by the motor control unit 46.

  The power circuit unit 45 includes an inverter 45a that converts DC power of the battery 47 into three-phase AC power used to drive the electric motor 1, and a PWM driver 45b that controls the inverter 45a. The inverter 45a is composed of a plurality of semiconductor switching elements (not shown). The PWM driver 45 b pulse-width modulates the input current command and gives an on / off command to each of the semiconductor switching elements.

  The motor control unit 46 is configured by a computer, a program executed by the computer, and an electronic circuit, and includes a motor drive control unit 48 as a control unit that is a basis of the computer. The motor drive control unit 48 is a means for converting the current command into a current command in accordance with an acceleration / deceleration command by a torque command or the like given from the ECU 43 and giving the current command to the PWM driver 45b. The motor drive control unit 48 obtains the motor current flowing from the inverter 45a to the electric motor 1 from the current detection unit 35, and performs current feedback control. Further, as described above, the motor drive control unit 48 performs vector control by obtaining the rotation angle of the motor rotor 10 (FIG. 1) from the rotation speed detection sensor Sc.

  The motor control unit 46 is provided with an oil level abnormality detection unit 41 as a determination unit, an abnormality control unit 49, and an abnormality report unit 50. The oil level height abnormality detecting means 41 is a lubricating oil in the electric motor 1 (i.e., based on the temperatures detected by the first and second coil temperature detecting means Sa and Sb, respectively, when the vehicle state is determined. It is determined whether or not the in-motor lubricating oil reservoir 31 (FIG. 1) is sealed at a defined oil level H (FIG. 1).

  The oil level height abnormality detection means 41 includes a vehicle state determination unit 41a, a detection unit 41b, and an operation comparison unit 41c. The vehicle state determination unit 41a determines whether or not the current vehicle state is a defined vehicle state. The determined vehicle state means that the time when the vehicle is started, or when the vehicle speed detected by the vehicle speed detection means Sd provided in the vehicle is equal to or less than a predetermined speed, or the time determined after the vehicle stops And at least one of them.

  When determining whether or not the vehicle is starting, the vehicle state determination unit 41a determines that the vehicle is starting by detecting that the power supply 51 of the vehicle is switched from off to on. When it is determined whether or not a predetermined time has passed after the vehicle is stopped, the vehicle state determination unit 41a uses the fact that the vehicle speed detected by the vehicle speed detection unit Sd becomes zero as a trigger for starting the time measurement. Thereafter, it is determined whether the elapsed time has been reached while the vehicle speed is zero.

By the way, with respect to the oil level H of the lubricating oil (FIG. 1), immediately after the operation of the vehicle, lubrication before the operation of the vehicle is started by storage in the lubricating flow passage, adhesion to the wall surface in the in-wheel motor drive device, etc. There is a difference between the oil level of the oil and the oil level of the lubricating oil immediately after operation. Therefore, it is desirable that the above-described determination of the oil level H (FIG. 1) is performed after a predetermined time has elapsed after the driving of the vehicle is stopped or immediately before the driving of the vehicle. Alternatively, it may be determined as one item of an abnormality check item at the time of start of the vehicle of the entire vehicle, which is performed when the power supply 51 of the vehicle is input. In addition, it may be judged independently instead of one item of the abnormality check item of the whole vehicle. At that time, the oil level may be determined by sending a signal from an external switch (not shown).
By performing the determination of the oil level height H (FIG. 1) at such a timing that a difference in the oil level does not easily occur, it is possible to always obtain a stable determination result.

  When it is determined by the vehicle state determination unit 41a that the current vehicle state is a determined vehicle state, the motor drive control unit 48 controls the inverter 45a to supply a constant current to the motor coil 78, and the detection unit 41b Respectively detect the temperatures of the first and second coil temperature detection units Sa and Sb. The constant current supplied to the motor coil 78 is preferably supplied so that no torque is generated. Specifically, when the motor drive control unit 48 performs vector control, it is desirable to perform control so that only the d-axis current flows. This is because when the driving torque by the electric motor 1 is generated, the oil level may adversely affect the determination of the corrugated oil level.

  The arithmetic and comparison unit 41c determines the lubricating oil by comparing the degree of increase in temperature detected by the first coil temperature detection means Sa with the degree of increase in temperature detected by the second coil temperature detection means Sb. It is determined whether the oil level H (FIG. 1) is sealed. This is because, in the case where each motor coil 78 has the same calorific value, the first coil temperature detection means Sa, the periphery of which is not filled with lubricating oil, reacts hypersensitively to the heat generation of the motor coil 78. In the second coil temperature detection means Sb whose periphery is filled with lubricating oil, the heat generation of the motor coil 78 transfers heat to the surrounding lubricating oil by heat transfer and heat conduction, and the temperature of the motor coil 78 rises. It is a difficult condition. For this reason, it utilizes that the temperature rise degree with respect to time of coil temperature detection means Sa and Sb differs.

  FIG. 7 is a diagram showing an example of temperature change by the first and second coil temperature detection means. Hereinafter, description will be made with reference to FIG. 6 as appropriate. The degree of increase in temperature detected by the first coil temperature detection means Sa is the detection value T1 of the first coil temperature detection means Sa when a predetermined time Δt has elapsed after the start of temperature detection, and the second The degree of increase in temperature detected by the coil temperature detection means Sb is the detection value T2 of the second coil temperature detection means Sb when a predetermined time Δt has elapsed after the start of temperature detection. The temperature detection start time of the first and second coil temperature detection means Sa and Sb is the same time. In this embodiment, regardless of the temperatures of the first and second coil temperature detection means Sa and Sb at the start of the temperature detection, the first and second at the time when the determined time Δt has passed after the start of the temperature detection. The detection values T1 and T2 of the temperatures of the coil temperature detection means Sa and Sb are detected.

The operation comparison unit 41c is configured such that the detection value T1 of the first coil temperature detection means Sa is larger than the detection value T2 of the second coil temperature detection means Sb, and the difference ΔT obtained by subtracting the detection value T2 from the detection value T1. Determines that the lubricating oil is enclosed at a defined oil level and is normal when the condition that the first threshold value or more is satisfied is satisfied. The first threshold is determined by the results of tests and simulations.
The calculation comparison unit 41c satisfies the condition that the detected value T1 is larger than the detected value T2 and the difference ΔT obtained by subtracting the detected value T2 from the detected value T1 is less than the first threshold, or When the value T1 is equal to or less than the detection value T2, it is determined that the lubricating oil is in an abnormal state in which the lubricating oil is not sealed at a predetermined oil level.

As shown in FIG. 6, when it is determined that the abnormality is occurring, the operation comparison unit 41c sends the abnormality occurrence information to the abnormality reporting means 50 and the abnormality time control means 49, respectively.
The abnormality control unit 49 instructs the power circuit unit 45 via the motor drive control unit 48 to limit the current of the electric motor 1 when it is determined by the operation comparison unit 41 c that an abnormality occurs. In this case, the abnormal state control means 49 may reduce the motor current at a fixed rate with respect to the motor current when the vehicle is traveling, or may decrease the set value. When it is determined that the operation comparison unit 41c is in the abnormal state and then returns to the normal state, the output restriction to the electric motor 1 is released.

  The abnormality report means 50 outputs the abnormality occurrence information to the ECU 43 when the abnormality occurrence information is given from the operation comparison unit 41 c. The abnormality display means 52 provided in the ECU 43 receives the abnormality occurrence information outputted from the abnormality report means 50, and causes the display device 27 provided on the console panel of the vehicle or the like to display an indication of the abnormality, for example. This alerts the driver. Therefore, it is possible to take measures such as moving the vehicle to a repair shop etc. at an early stage.

  According to the in-wheel motor drive described above, when it is determined that the vehicle state is determined by the vehicle state determination unit 41a, the motor drive control unit 48 controls so as to supply a constant current to the motor coil 78 and detects it. The unit 41 b detects the temperatures of the first and second coil temperature detection units Sa and Sb, respectively. The arithmetic and comparison unit 41c determines the oil level at which the lubricating oil to be sealed in the in-motor lubricating oil storage portion 31 is determined based on the temperatures detected by the first and second coil temperature detection means Sa and Sb respectively. It is determined whether it is enclosed by height.

  This is because, in the case where each motor coil 78 has the same calorific value, the first coil temperature detection means Sa, the periphery of which is not filled with lubricating oil, reacts hypersensitively to the heat generation of the motor coil 78. In the second coil temperature detection means Sb whose periphery is filled with lubricating oil, the heat generation of the motor coil 78 transfers heat to the surrounding lubricating oil by heat transfer and heat conduction, and the temperature of the motor coil 78 rises. It is a difficult condition. For this reason, it utilizes that the temperature rise degree with respect to time of coil temperature detection means Sa and Sb differs.

  The coil temperature detection means Sa, Sb can be obtained inexpensively and easily from commercially available products etc. The first coil temperature detection means Sa whose periphery is not filled with lubricating oil detects an overload of the electric motor 1 originally It is often provided to By adding a second coil temperature detection means Sb whose periphery is filled with lubricating oil to the configuration provided with such a first coil temperature detection means Sa, the arithmetic and comparison unit in the oil level height abnormality detection means 41 41c can compare the degree of increase in temperature and use it for determination. Therefore, the apparatus can be miniaturized and the cost can be reduced as compared with the prior art or the like which requires a space for emitting and receiving laser light.

The first coil temperature detection means Sa is disposed above the central axis L1 of the electric motor 1, and the second coil temperature detection means Sb is disposed below the central axis L1. For this reason, the first coil temperature detection means Sa is less susceptible to the influence of lubricating oil, and can detect the heat generation of the motor coil 78 to be detected with high sensitivity. In the second coil temperature detecting means Sb, heat generation of the motor coil 78 to be detected is transferred to the surrounding lubricating oil by heat transfer and heat conduction, and the temperature of the motor coil 78 is made more difficult to rise. Can.
When it is determined by the arithmetic and comparison unit 41c that the lubricating oil is not sealed at the defined oil level height, the abnormal time control means 49 limits the current of the electric motor 1 to thereby overload the electric motor 1 It becomes possible to prevent and to prevent the reduction gear 2 from becoming a lubrication failure beforehand.

Another embodiment will be described.
In the following description, the portions corresponding to the items described in the preceding embodiments are given the same reference numerals, and the redundant description will be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding embodiment unless otherwise stated. The same function and effect can be obtained from the same configuration. Not only the combination of the portions specifically described in the embodiments but also the embodiments may be partially combined if any problem does not occur in the combination.

  As shown in FIG. 8, a plurality of (two in this example) first coil temperature detection means Sa may be provided, and a plurality (two in this example) second coil temperature detection means Sb may be provided. The plurality of first coil temperature detection means Sa which are not immersed in the lubricating oil have teeth 77a located vertically above the central axis L1 of the electric motor 1 in the vertical direction, and both sides of the teeth 77a in the circumferential direction. It is arrange | positioned between teeth 77a and 77a, respectively. The plurality of second coil temperature detection means Sb immersed in the lubricating oil have teeth 77a located vertically below the central axis L1 in the vertical direction, and teeth 77a on both sides in the circumferential direction of the teeth 77a. , 77a, respectively.

  In this case, the detection unit 41b (FIG. 6) detects the temperatures of the plurality of first coil temperature detection means Sa and the temperatures of the plurality of second coil temperature detection means Sb. The arithmetic comparing unit 41c (FIG. 6) detects the average value of the temperatures detected by the plurality of first coil temperature detection means Sa not immersed in the lubricating oil and the plurality of second coil temperature detections immersed in the lubricating oil. The average value of the temperature detected by means Sb is compared. In this case, the value to be averaged may be a detected temperature after a predetermined time or a temperature change (differential value) after a predetermined time.

When all the following conditions are satisfied, the arithmetic comparison unit 41c (FIG. 6) determines that the lubricating oil is sealed at a defined oil level and that it is normal.
(T1ave = (T1a + T1b) / 2)> (T2ave = (T2a + T2b) / 2)
ΔT = (T1ave−T2ave) ≧ first threshold (T2a−T2b) ≦ second threshold

  However, T1a: temperature detected by one first coil temperature detection means Sa, T1b: temperature detected by the other first coil temperature detection means Sa, T1ave: average value of T1a and T1b, T2a: one T2ave: temperature detected by the second coil temperature detection means Sb, temperature detected by the other second coil temperature detection means Sb, T2ave: average value of T2a and T2b, ΔT: T1ave subtracted from T2ave It is a difference. The same applies to the following conditions at the time of abnormality, immediately before notification of abnormality, and conditions of other embodiments. The first and second threshold values are respectively determined by the results of tests and simulations.

When all the following conditions are satisfied, the arithmetic comparison unit 41c (FIG. 6) determines that the lubricating oil is in an abnormal state where it is not enclosed at a defined oil level.
(T1ave = (T1a + T1b) / 2)> (T2ave = (T2a + T2b) / 2)
ΔT = (T1ave−T2ave) <first threshold value, or T1ave ≦ T2ave

  In the case where a plurality of second coil temperature detection means Sb are provided as in the present embodiment, the arithmetic and comparison unit 41c (FIG. 6) is in the normal state at the present, but when it reaches the abnormal state in a little more Information as a warning is given to the abnormality reporting means 50 (FIG. 6). This information is output to the ECU 43 (FIG. 6), and the abnormality display means 52 provided in the ECU 43 receives the information output from the abnormality report means 50 and, for example, the display device 27 is reached a little more abnormal. Make warning display.

When all the following conditions are satisfied, the operation comparison unit 41c (see FIG. 6) gives information as a primary warning to the abnormality reporting unit 50 (see FIG. 6). The conditions are milder than the above-described abnormal conditions.
T1ave> T2ave
ΔT = (T1ave−T2ave) ≧ first threshold (T2a−T2b)> second threshold

  When the average value is compared in this manner, it can be more accurately determined whether normal or abnormal than the embodiment shown in FIG. 4 etc. described above. In addition, by providing a plurality of second coil temperature detection means Sb, it is possible to judge the level of the liquid level to some extent, and it is now normal but when it is a little more abnormal, information as a primary alert As it can be obtained, the driver of the vehicle can be alerted early.

As shown in FIG. 9, a plurality of (in this example, three) second coil temperature detection means Sb may be provided. Note that only one first coil temperature detection means Sa is provided. According to the configuration of FIG. 9, substantially the same function and effect as the example of FIG. 8 can be obtained.
In the example of FIG. 9, when all the following conditions are satisfied, the operation comparison unit 41c (FIG. 6) determines that the operation is normal.
T1> (T2ave = (T2a + T2b + T2c) / 3)
ΔT = (T1−T2ave) ≧ first threshold (T2a−T2b) ≦ second threshold, or (T2a−T2c) ≦ second threshold However, T2c is a third second coil temperature detection It is the temperature detected by means Sb.

When all the following conditions are satisfied, the operation comparison unit 41c determines that an abnormality has occurred.
T1> (T2ave = (T2a + T2b + T2c) / 3)
ΔT = (T1−T2ave) <first threshold or T1 ≦ T2ave

When all the following conditions are satisfied, the operation comparison unit 41c (see FIG. 6) gives information as a primary warning to the abnormality reporting unit 50 (see FIG. 6).
T1> (T2ave = (T2a + T2b + T2c) / 3)
ΔT = (T1−T2ave) ≧ first threshold value (T2a−T2b)> second threshold value or (T2a−T2c)> second threshold value In FIG. The oil level height at the time of giving the first warning is low, and the oil level height at the time of abnormality is lower than the oil level at the first warning.

  As shown in FIG. 10, the first coil temperature detection means Sa is provided on the outer peripheral surface of the coil end 78a of the motor coil 78 located on the uppermost side in the vertical direction, and the second coil temperature detection means Sb is in the vertical direction It may be provided on the outer peripheral surface of the coil end 78a of the motor coil 78 located at the lowermost position. In this case, the coil temperature detection means Sa and Sb can be installed more easily than installing between so-called slots. This can further reduce the cost.

  As shown in FIG. 11, the second coil temperature detection means Sb may be provided more than the example of FIG. In this example, the calculation comparison unit 41c determines whether or not the detection of the normal value is performed on the measurement values of the coil temperature detection means Sa and Sb arranged at six places. Each coil temperature detection means Sa, Sb detects a change in resistance value with temperature by a change in voltage and current given in advance. In order to apply a constant voltage to each coil temperature detection means Sa and Sb, in the case of disconnection or resistance abnormality, a value outside the specified value is detected. As a result, the calculation comparison unit 41c (see FIG. 6) determines whether or not the measured values of the coil temperature detection means Sa and Sb are normal values. After determining that the measured value is a normal value, the operation comparison unit 41 c compares the measured value.

  The calculation comparison unit 41c compares the temperature detection values after a predetermined time after the start of measurement, and determines the oil level height (oil level). In the example of FIG. 11, among the plurality of coil temperature detection means Sb arranged below the central axis L1 of the electric motor 1, the average value (first detected value) of the upper two measured values and the lower one The oil level is determined from the average value of the two measured values (second detected value).

Within a defined range of the first and second detection values, the smaller the difference between the first detection value and the second detection value, the higher the oil level. As the second detection value is lower than the first detection value and the difference between the two detection values is larger, the oil level is lower. As the value used to determine the oil level, not only the temperature detection value after a predetermined time but also the slope of the detection value after a predetermined time may be used.
By performing the calculation as described above, the first and second detection values can be obtained even when the vehicle is stopped at a steady position, when the vehicle is stopped on a road surface having a slope, and when the oil level changes. It is possible to determine the oil level using

The calculation comparison unit 41c (see FIG. 6) compares the differential values of the detection values when a predetermined time has elapsed after the start of temperature detection by the first and second coil temperature detection means Sa and Sb. Also good.
In this case, for example, when each of the first and second coil temperature detection means Sa and Sb is provided, the operation comparison unit 41c determines that the normal condition is satisfied when all the following conditions are satisfied. Do.

dT1 / dt> dT2 / dt
However, T1 / dt is a measurement temperature of the first coil temperature detection means Sa, and T2 / dt is a measurement temperature of the second coil temperature detection means Sb. same as below.
When all the following conditions are satisfied, the operation comparison unit 41c determines that an abnormality has occurred.
dT1 / dt ≦ dT2 / dt

When one first coil temperature detection means Sa is provided and two second coil temperature detection means Sb are provided, it is determined that the calculation and comparison unit 41c is normal when all the following conditions are satisfied. judge.
dT1 / dt> (dT2ave / dt = (dT2a / dt + dT2b / dt) / 2)
(DT1 / dt−dT2ave / dt) ≧ first threshold (dT2b / dt−dT2a / dt) ≦ second threshold where T2a / dt: measurement temperature a of one second coil temperature detecting means Sb, T2b / Dt: measurement temperature b of the other second coil temperature detection means Sb

In the case where one first coil temperature detection means Sa is provided and two second coil temperature detection means Sb are provided, the arithmetic comparison section 41c determines that it is an abnormal state when all the following conditions are satisfied. judge.
dT1 / dt> (dT2ave / dt = (dT2a / dt + dT2b / dt) / 2)
(DT1 / dt−dT2ave / dt) <first threshold, or dT1 / dt ≦ dT2ave / dt

In the case where one first coil temperature detection means Sa is provided and two second coil temperature detection means Sb are provided, the arithmetic comparison section 41 c generates a first warning when all the following conditions are satisfied. Information to the anomaly report means 50.
dT1 / dt> (dT2ave / dt = (dT2a / dt + dT2b / dt) / 2)
(DT1 / dt−dT2ave / dt) ≦ first threshold (dT2b / dt−dT2a / dt)> second threshold

FIG. 12 is a view showing a schematic configuration of a vehicle equipped with this in-wheel motor drive device. In this vehicle, left and right rear wheels 53, 53 are driven by independent electric motors 1, respectively. Each electric motor 1 constitutes an in-wheel motor drive device. In the in-wheel motor drive device of this embodiment, rear wheel drive is shown, but front wheel drive or four wheel drive may be used.
Although a cycloid reducer is applied as a reducer of the in-wheel motor drive device, a planetary reducer, a parallel two-axis reducer, and other reducers are applicable.

  As mentioned above, although the form for implementing this invention was demonstrated based on embodiment, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Decelerator 5 ... Wheel bearing 31 ... In-motor lubricating oil storage part 41 ... Oil level height abnormality detection means (determination means)
43: ECU (upper control means)
44: Inverter device (control device)
49: Abnormality control means 50: Abnormality report means Jk ... Lubricating oil supply mechanism Sa, Sb: First, second coil temperature detection means Sd: Vehicle speed detection means

Claims (5)

An electric motor for driving a wheel, a wheel bearing for rotatably supporting the wheel, a reduction gear for decelerating the rotation of the electric motor and transmitting the rotation to the wheel bearing, lubrication of the reduction gear, and cooling of the electric motor In the in-wheel motor drive provided with a lubricating oil supply mechanism for supplying lubricating oil used in both of the above and a controller for controlling the electric motor,
The lubricating oil supply mechanism includes an in-motor lubricating oil storage portion for sealing the lubricating oil supplied to the electric motor at an oil level defined in the electric motor, and the lubricating oil is provided in the electric motor. A first coil temperature detection means for detecting the temperature of the motor coil not immersed and a second coil temperature detection means for detecting the temperature of the motor coil immersed in the lubricating oil;
The control device determines whether or not the lubricating oil in the electric motor is sealed at the determined oil level based on the temperatures respectively detected by the first and second coil temperature detecting means. An in-wheel motor drive characterized by having judgment means for judging.   The in-wheel motor drive device according to claim 1, wherein the first coil temperature detection means is disposed above the central axis of the electric motor, and the second coil temperature detection means is connected to the central axis. The in-wheel motor drive is also located below.   The in-wheel motor drive device according to claim 1 or 2, further comprising: a vehicle speed detection means for detecting a vehicle speed, wherein the determination means determines the vehicle speed detected by the vehicle start time or by the vehicle speed detection means. The in-wheel motor drive device which performs determination, when it is less than the fixed value, or after predetermined time passes after a vehicle stop.   The in-wheel motor drive device according to any one of claims 1 to 3, wherein the control device is determined by the determination means that the lubricating oil is not enclosed at the predetermined oil level height. The in-wheel motor drive device which has an abnormality report means which outputs abnormality occurrence information to the high-order control means of the said control apparatus. The in-wheel motor drive device according to any one of claims 1 to 4, wherein the control device is determined by the determination means that the lubricating oil is not enclosed at the predetermined oil level height. The in-wheel motor drive device which has an abnormal-time control means to limit the electric current of the said electric motor when it was.

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