JP2005073382A - Motor driving unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driving unit which easily detects the oil leakage caused by the deterioration of a seal member, and also prevents the oil contamination of a motor room due to oil leakage. <P>SOLUTION: In the motor driving unit 100 where a motor chamber S12 to house the stator 78 and the rotor 79 of a motor and a reduction gear chamber S10 to house a reduction gear are coupled directly with each other and which decelerates the rotation of a motor rotary shaft 76 by the reduction gear and outputs it from an output shaft 71, the motor rotary shaft 76 is provided with a seal member 86 which seals lubricating oil filled in the reduction gear chamber S10 and a seal member 84 which is mounted apart on the side of the motor chamber S12, Then, a discharge port 85 connects the space S11 made between the seal member 86 and the seal member 84 with the outside of the motor drive unit 100. The lubricating oil leaked out from the reduction gear S10 to the space S11 is discharged outside by the discharge port 85, and it is visually checked easily. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor drive unit used for vehicle travel.

  As a vehicle driving motor, an inverter, a motor, and a speed reducer are integrated by using a coaxial mechanism (for example, see Patent Document 1). In this coaxial mechanism, the motor rotation shaft has a hollow structure, and the output shaft is disposed so as to penetrate the motor rotation shaft. An output shaft that rotates in conjunction with the motor rotation shaft extends from both ends of the motor rotation shaft to the outside, and has a structure that drives both the left and right wheels of the vehicle.

  In such a coaxial mechanism, it is common to provide a separate oil supply mechanism for each bearing that rotatably supports the motor rotation shaft and the output shaft, or to use a grease-filled bearing for each bearing. It was.

  In the case of individually supplying oil to each bearing, an oil chamber is provided and the lubricating oil is sealed with an oil seal or the like. Generally, a rubber material is used for the oil seal used as the seal member of the rotating shaft, and the sealing performance is maintained between the seal member and the rotational sliding portion on the rotating shaft side.

JP 7-298552 A

  However, the sealing performance may be deteriorated due to deterioration of the rubber material with the passage of time or mixing of foreign matters into the rotational sliding portion. In such a case, the lubricating oil may leak from the sealing member and enter the adjacent motor chamber, and as a result, the lubricating oil may adhere to electrical parts such as windings, leading to deterioration of the insulating properties. It was. Further, the intrusion of the lubricating oil into the motor chamber due to such deterioration of the seal member is difficult to detect visually from the outside, and thus has a problem that it is difficult to notice until a malfunction occurs.

According to the first aspect of the present invention, an electric motor and a speed reducer that decelerates and outputs the rotation of the electric motor are directly connected, and a seal that prevents the lubricant of the speed reducer from entering the electric motor is provided with a motor rotation of the electric motor. It is applied to the motor drive unit provided on the shaft. The seal is composed of a pair of seal members provided at an interval, and a gap space is formed between the pair of seal members. A discharge hole communicating with the external space of the motor drive unit is formed in the clearance space, and the lubricating oil leaking into the clearance space is discharged from the discharge hole to the external space.
According to a third aspect of the present invention, an electric motor and a differential reducer that decelerates the rotation of the electric motor and distributes it to the left and right drive shafts are directly connected, and are provided on the opposite side of the differential reducer across the electric motor. A lubricating oil chamber for oil lubrication of one of the driving shafts, and a seal that is attached to the motor rotating shaft of the electric motor and prevents the lubricating oil in the differential reduction gear and the lubricating oil chamber from entering the electric motor. And is applied to a motor drive unit including The seal is composed of a pair of seal members provided at an interval, and a gap space is formed between the pair of seal members. A discharge hole communicating with the external space of the motor drive unit is formed in the clearance space, and the lubricating oil leaking into the clearance space is discharged from the discharge hole to the external space.

  According to the present invention, when an oil leak occurs in the seal member sealing the lubricant, the leaked lubricant enters the space adjacent to the seal member and is discharged from the discharge hole to the outside of the motor drive unit. Is done. Therefore, the oil leakage of the seal member can be easily detected by visually confirming the discharge of the lubricating oil. Further, since the space where the lubricating oil has leaked and the motor chamber are separated from each other by the sealing member, the intrusion of the lubricating oil from the space into the motor chamber is prevented.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
-First embodiment-
FIG. 1 is a sectional view of a motor drive unit 1 according to the present invention. The motor drive unit 1 is used in a vehicle drive device, and is mounted horizontally on the vehicle 2 as shown in FIG. In the example shown in FIG. 2, the motor drive unit 1 is used to drive the left and right wheels 3 and 4, and power is supplied from the battery 5.

  As shown in FIG. 1, the motor drive unit 1 is provided with a motor unit 6 at the center, a differential reducer unit 7 on the left side, and an inverter unit 8 on the right side. Although not shown, an oil-tight seal is provided at the attachment portion between the motor unit 6 and the differential reduction gear unit 7. In FIG. 1, the left-right direction matches the horizontal direction, and the up-down direction matches the top-bottom direction.

  The motor unit 6 is provided with a stator 10 provided with a winding 9 and a rotor 12 fixed to the motor rotating shaft 11, and the stator 10 and the rotor 12 constitute an electric motor. The rotor 12 and the stator 10 are each made by laminating electromagnetic steel plates in the axial direction, and are fixed to the motor rotating shaft 11 and the casing 13 by shrink fitting or the like. The motor rotation shaft 11 is a hollow shaft, and is rotatably supported by a bearing 14 provided in the central casing 13 and a bearing 16 provided in the right casing 15.

  Reference numeral 17 denotes a drive shaft that drives the right wheel 3 and is disposed so as to penetrate the hollow portion of the motor rotating shaft 11 from side to side. The left and right ends of the drive shaft 17 extend to the outside of the motor rotating shaft 11, and the right end thereof is rotatably supported by a bearing 18 provided in the casing 15. On the other hand, the left end portion of the drive shaft 17 extending from the left end of the motor rotating shaft 11 into the casing 19 of the differential reduction gear unit 7 is rotatably supported by a bearing 20 provided in the casing 19.

  The right end portion of the motor rotating shaft 11 protrudes to the right from the bearing 16, and the protruding amount is set so that the right end of the motor rotating shaft 11 is in the vicinity of the installation position of the bearing 18. On the other hand, the left end portion of the motor rotating shaft 11 extends into the casing 19 of the differential reduction gear unit 7, and a sun gear constituting a planetary gear reduction mechanism is formed on the outer peripheral surface thereof. A plurality of planetary gears 21 mesh with the sun gear, and each planetary gear 21 meshes with a ring gear 22 fixed to the casing 19. The planetary gear 21, the ring gear 22, and the sun gear formed on the motor rotation shaft 11 constitute a planetary gear reduction mechanism.

  The revolution shaft output of the planetary gear 21 is taken out by a planetary carrier 24 that is rotatably supported by a bearing 23. The planetary carrier 24 also serves as a differential case, and the differential gear mechanism 25 is rotated by the rotation of the planetary carrier 24. One output shaft of the differential gear mechanism 25 constitutes a drive shaft 26 for driving the left wheel 3, and the other output shaft constitutes a drive shaft 17 for driving the right wheel 4. The bearing 20 described above is provided on the planetary carrier 24. The drive shaft 26 is rotatably supported by a bearing 27 provided on the casing 19 of the differential reduction gear unit 7 and a bearing 28 provided on the planetary carrier 24.

  A cover 29 is provided on the outer periphery of the casing 15 of the inverter unit 8, and the electric motor is controlled and driven in a space S7 (hereinafter referred to as an inverter chamber S7) formed by the cover 29 and the casing 15. An inverter unit 30 is provided. The DC power from the battery 5 described above is converted into a drive voltage necessary for the electric motor by a switching element or the like provided in the inverter unit 30 and is fed to the winding 9 of the stator 10.

  The casing 19 is filled with a lubricating oil 31 for oil-lubricating gears and bearings. The lubricating oil 31 is an oil seal or the like provided in a gap between the casing 19 and the drive shaft 26 and the motor rotating shaft 11. Sealed by seal members 40 and 41. The right casing 15 is also filled with lubricating oil 31 for the bearings 16 and 18 and is lubricated by seal members 42 and 43 provided in the gap between the casing 15 and the drive shaft 17 and the motor rotating shaft 11. The oil 31 is sealed.

  The space S <b> 1 in the casing 19 and the space S <b> 3 in the casing 15 communicate with each other by a gap space S <b> 4 between the motor rotating shaft 11 and the drive shaft 17. The lubricating oil 31 in the casing 19 and the lubricating oil 31 in the casing 15 are connected to each other to form an oil reservoir made of the common lubricating oil 31.

  Further, seal members 44 and 45 are also provided between the motor chamber S <b> 2 where the stator 10 is provided and the seal members 41 and 43. The seal member 41 and the seal member 44 are disposed with an interval in the axial direction, and the space S5 sandwiched between the seal members 41 and 44 communicates with the external space through a hole 50 penetrating vertically downward. . Similarly, the seal members 43 and 45 are also arranged at intervals in the axial direction, and the space S6 sandwiched between the seal members 43 and 45 communicates with the external space through a hole 51 penetrating vertically downward. .

  The motor drive unit 1 shown in FIG. 1 is mounted so that the vertical direction in the figure matches the vertical direction of the vehicle 2 as described above. Therefore, in the unlikely event that the seal members 41 and 43 deteriorate and oil leakage occurs, the lubricating oil leaked into the spaces S5 and S6 drops onto the ground through the holes 50 and 51. As a result, the user can easily detect the oil leakage visually by observing the dripping of the lubricating oil.

  In general, since the motor drive unit 1 is disposed at a relatively low position of the vehicle 2, for example, the motor drive unit 1 itself may be submerged when traveling on a submerged channel. In such a case, water permeates into the holes 50 and 51. However, since the seal members 44 and 45 are also provided between the spaces S5 and S6 and the motor chamber S2, the motor chamber S2 and the differential deceleration are provided. It is possible to prevent water from entering the space S1 of the machine part 7.

  The motor chamber S2 communicates with the inverter chamber S7 through a through hole 52 formed in the casing 15. Further, a hole 53 penetrating vertically upward is formed in the cover 29 of the inverter chamber S7. A resin tube 55 is connected to the hole 53 by a piping component 54. Similarly, a hole 56 penetrating vertically upward is also provided in the casing 19 of the differential reduction gear unit 7, and a resin tube 58 is connected to the hole 56 by a piping component 57.

  The other end of each resin tube 55, 58 is fixed at a relatively high position of the vehicle, and the spaces S1, S2, S7 are opened to the atmosphere. As a result, the pressure before and after sandwiching the seal members 40 to 45 is atmospheric pressure in any case. Normally, a seal member such as an oil seal has a specified value that can ensure a sealing property with respect to the differential pressure across the front and back, and is generally about “specified differential pressure before and after = 0.1 MPa≈1 atm”. In the present embodiment, as described above, the front-rear differential pressure is set to be zero, so that oil leakage due to the front-rear differential pressure can be avoided.

  As described above, since the motor drive unit 1 may be submerged, fixing the other end of the air release tubes 55 and 58 to a high position of the vehicle 2 prevents water from entering the motor drive unit. It is preventing. In this case, the motor chamber S2 and the inverter chamber S7 are communicated with each other through the through-hole 52, and the air release tube 58 is provided only in the inverter chamber S7. Therefore, the number of air release tubes can be reduced. .

  Note that the through hole 52 between the motor chamber S2 and the inverter chamber S7 is not necessarily formed as a dedicated hole as described above. For example, the casing 15 is formed with a hole through which the power supply line from the inverter unit 30 to the winding 9 is passed. The diameter of the hole is larger than the thickness of the power supply line so that the through hole 52 is also used. Also good.

  FIG. 3 is a view showing a modification of the motor drive unit 1 shown in FIG. In the modification shown in FIG. 3, a through hole 60 is formed in the casing 13 of the motor unit 6 so that the space S1 of the differential reduction gear unit 7 and the motor chamber S2 communicate with each other. Therefore, the three spaces S1, S2, and S7 can be opened to the atmosphere simply by providing the inverter chamber S7 with the tube 55 for opening to the atmosphere. As a result, the cost can be reduced by reducing the number of parts, and the layout can be improved when the motor drive unit 1 is mounted on a vehicle.

  The through hole 60 is provided with a filter 61 for preventing the lubricating oil or the lubricating oil mist from entering the motor chamber S2. As the filter 61, for example, a resin-based porous sheet that is a sheet-like filter that allows air to pass but does not allow liquid such as oil to pass therethrough is used. The hole shape may be a labyrinth structure so that the lubricating oil does not enter the through hole 60 directly.

-Second Embodiment-
FIG. 4 is a view showing a second embodiment of the seal structure according to the present invention. A motor drive unit 100 shown in FIG. 4 includes a motor unit 101 and a speed reducer unit 102, and a rotational driving force is supplied by an output shaft 71. The motor rotation shaft 76 is rotatably supported by a bearing 87 provided on the casing 77 and a bearing 82 provided on the end plate 81. The rotor 79 and the stator 78 are made by laminating electromagnetic steel plates in the axial direction in the same manner as the rotor 12 and the stator 10 described above. Reference numeral 80 denotes a winding provided on the stator 78.

  A sun gear 88 constituting a planetary gear speed reducer is formed at the speed reducer side end of the motor rotation shaft 76, and a plurality of planetary gears 74 are engaged with the sun gear 88. Each planetary gear 74 is fixed to the planetary carrier 91 and meshes with a ring gear 89 fixed to the casing 72. The planetary gear 74, the ring gear 89, the planetary carrier 91, and the sun gear 88 formed on the motor rotating shaft 76 constitute a planetary gear reduction mechanism. That is, the rotation of the motor rotation shaft 76 is decelerated and output from the planetary carrier 91. The output shaft 71 described above is connected to the planetary carrier 91, and these are rotatably supported by bearings 92 and 93 provided on the casing 72.

  A gap between the output shaft 71 and the casing 72 is sealed by a seal member 94 such as an oil seal. Further, the gap between the motor rotating shaft 76 and the casing 77 is sealed by seal members 84 and 86. The reduction gear chamber S10 formed by the casing 77 is filled with lubricating oil for lubricating gears and bearings, and the sealing members 94, 86, and 84 are filled with lubricating oil filled in the reduction gear chamber S10. Leakage to the outside of the drive unit 100 and the motor chamber S12 is prevented.

  The seal members 84 and 86 are disposed with an interval in the axial direction, and a space S11 formed between the seal members 84 and 86 communicates with the outside through a through hole 85 formed in a vertically downward direction. Yes. The casing 72 is formed with a through hole 73 for opening the reduction gear chamber S10 to the atmosphere, and the end plate 81 is formed with a through hole 83 for opening the motor chamber S12 to the atmosphere. Tubes 103 and 104 for opening to the atmosphere are connected to the respective through holes 73 and 83 by piping parts 105 and 106, and the other ends of the tubes 103 and 104 are fixed at a relatively high position of the vehicle.

  Also in the second embodiment, when the lubricating oil leaks into the space S11 due to the deterioration of the sealing member 86, it can be visually observed that the lubricating oil drops from the through hole 85, so that the oil from the sealing member 86 Leakage can be easily detected. Further, by providing another seal member 84 closer to the motor chamber S12 than the seal member 86, it is possible to prevent the leaked lubricating oil from entering the motor chamber 12. Further, even when the motor drive unit 100 is submerged and water enters the space S11, the seal member 84 can prevent water from entering the motor chamber S12. Further, since the front and rear pressures of the seal members 84, 86, and 94 are all atmospheric pressure and the differential pressure becomes zero, it is possible to avoid lubricating oil leakage due to the front and rear differential pressure of the seal members.

  In the above-described embodiment, the drive shaft 17 is connected to the right wheel 4 and the drive shaft 26 is connected to the left wheel 3. However, the drive shaft 17 may be mounted on the vehicle 2 so as to be connected in the opposite direction. The oil lubrication structure of the present invention can be applied to any similar coaxial mechanism, not limited to the motor drive unit shown in FIG. In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired.

  In the correspondence between the embodiment described above and the elements of the claims, the planetary gear 74, the ring gear 89 and the planetary carrier 91 are reduction gears, the spaces S5, S6 and S11 are clearance spaces, and the holes 50, 51 and 85 are The discharge holes, the holes 53, 56, 73 and 83 are through holes, the space S1 is a differential reduction gear chamber, the drive shafts 17 and 26 are left and right drive shafts, the space S4 is a gap, and the space S3 is a lubricating oil chamber. The hole 52 constitutes the communication hole of claim 5 and the first communication hole of claim 6, and the hole 60 constitutes the second communication hole.

It is sectional drawing of the motor drive unit 1 provided with the seal structure by this invention. FIG. 2 is a plan view showing a motor drive unit 1 mounted on a vehicle 2. It is a figure which shows the modification of the motor drive unit. It is a figure which shows 2nd Embodiment of the seal structure by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Motor drive unit 2 Vehicle 3, 4 Wheel 5 Battery 6,101 Motor part 7 Differential reduction part 8 Inverter part 9, 80 Winding 10,78 Stator 11,76 Motor rotating shaft 12,79 Rotor 13,15 , 19, 72, 77 Casing 14, 16, 18, 20, 23, 27, 28, 82, 87, 92, 93 Bearing 17, 26 Drive shaft 21, 74 Planetary gear 22, 89 Ring gear 24, 91 Planetary carrier 25 Differential Gear mechanism 30 Inverter unit 40-45, 84, 86, 94 Seal member 50, 51-53, 56, 60, 73, 83, 85 Hole 61 Filter 71 Output shaft 102 Reduction gear part S2, S12 Motor chamber S1, S3 S6, S11 Space S7 Inverter room S10 Reducer room

Claims (6)

An electric motor and a speed reducer that decelerates and outputs the rotation of the electric motor are directly connected, and a seal that prevents the lubricant of the speed reducer from entering the electric motor is provided on the motor rotation shaft of the electric motor. In the motor drive unit,
The seal consists of a pair of seal members provided at intervals,
A gap hole formed between the pair of seal members communicates with an external space of the motor drive unit, and a discharge hole for discharging the lubricating oil leaked into the gap space to the external space is provided. A motor drive unit characterized by that. The motor drive unit according to claim 1,
A reducer chamber in which the reducer is accommodated and filled with lubricating oil;
A motor chamber in which the electric motor is accommodated;
A motor drive unit, comprising: a through hole provided separately in the reduction gear chamber and the motor chamber and communicating with the external space to open the reduction gear chamber and the motor chamber to the atmosphere. An electric motor and a differential reducer that decelerates the rotation of the electric motor and distributes it to the left and right drive shafts are directly connected, and is provided on the opposite side of the differential reducer across the electric motor, and one of the left and right drive shafts A lubricating oil chamber that performs oil lubrication of the drive shaft, and a seal that is attached to the motor rotation shaft of the electric motor and prevents the lubricating oil in the differential reduction gear and the lubricating oil chamber from entering the electric motor. In the motor drive unit with
The seal consists of a pair of seal members provided at intervals,
A gap hole formed between the pair of seal members communicates with an external space of the motor drive unit, and a discharge hole for discharging the lubricating oil leaked into the gap space to the external space is provided. A motor drive unit characterized by that. In the motor drive unit according to claim 3,
A differential reducer chamber in which the differential reducer is housed;
A motor chamber in which the electric motor is accommodated,
The motor rotation shaft is constituted by a hollow shaft, and one of the left and right drive shafts is passed through the hollow portion of the motor rotation shaft with a gap, and the differential reduction gear chamber and the lubricating oil chamber are separated by the gap. A motor drive unit characterized in that the seal is provided on the differential reduction gear chamber side and the lubricating oil chamber side of the motor rotation shaft, respectively. In the motor drive unit according to claim 4,
An inverter chamber that is provided adjacent to the motor chamber and accommodates an inverter unit that drives the electric motor;
A communication hole communicating the motor chamber and the inverter chamber;
A motor drive unit comprising a through hole that opens the differential reduction gear chamber and the inverter chamber to the atmosphere. In the motor drive unit according to claim 4,
A first communication hole communicating the motor chamber and the inverter chamber;
A second communication hole communicating the differential reduction gear chamber and the motor chamber;
A filter that is provided in the second communication hole and prevents the lubricant or lubricant mist from entering the motor chamber from the differential reduction gear chamber;
A motor drive unit comprising: the motor chamber, a differential reduction gear chamber, and a through hole that opens the inverter chamber to the atmosphere.

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