JP2008141864A - Wheel drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel drive which can efficiently restrain the temperature of a motor from rising due to transmission of frictional heat, at operation of a disc brake. <P>SOLUTION: A wheel drive 1, which is equipped with a case 3 which is attached to a vehicle via a suspension system 130, a motor 20 which includes a stator 21 and a rotor 22, an output shaft 80 whose one end is connected to a rotor 22 via a speed reducer 30 and whose other end is connected with a wheel 120 via a wheel hub 85, a disc brake 90 which is attached adjacent to the case 3, and a brake rotor disc 87 which is coupled with the wheel hub 85, is equipped with an oil cooler which cools oil, an oil pump 50 which supplies the cooled oil to the motor-side end face 80a of an output shaft 80 and an oil path 79 for cooling of the output shaft, and an oil quantity adjusting means which increases the quantity of oil supplied to the oil path 79 for cooling of the output shaft at operation of the disc brake 90. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel driving device that drives a wheel by a motor including a stator and a rotor, and more particularly to an improvement in cooling performance of the motor.

  2. Description of the Related Art Conventionally, a case attached to a vehicle via a suspension device, a motor provided in the case and including a stator and a rotor, and rotatably provided in the case, one end of the rotor via a speed reducer And the other end of the output shaft connected to the wheel via a wheel hub, a disc brake mounted adjacent to the case, and the wheel hub and clamped by a brake pad of the disc brake There is known a wheel drive device that includes a brake rotor disk that is provided so as to drive the wheel by the motor.

  Generally, since the efficiency of a motor changes with temperature, it is desirable to maintain the temperature of the motor near the most efficient temperature. However, since the motor used in the wheel driving device generates heat when a current flows through a stator coil provided in the stator, cooling is required to maintain the temperature.

Usually, the cooling of the motor is performed by the oil combined with the lubricating oil. Patent Document 1 discloses a wheel drive device (in-wheel motor) in which the cooling efficiency of the motor is improved by devising the oil circulation path.
JP 2005-73364 A

  However, the temperature of the motor does not necessarily increase due to heat generated by the motor (particularly the stator) itself, and may increase due to heat transfer from the outside.

  A typical example is when a disc brake is activated. As is well known, a disc brake is a device in which a brake rotor disc that rotates integrally with a wheel is strongly held by a brake pad, and a braking force is obtained by the frictional force thereof. When the disc brake is activated, a large amount of frictional heat is generated along with the frictional force. Since the wheel drive device is provided close to the brake rotor disk due to its layout, friction heat during braking is transmitted from the brake rotor disk to the motor via the wheel hub, output shaft, reducer, etc. There is a risk of temperature rise.

  In view of the circumstances as described above, an object of the present invention is to provide a wheel drive device capable of efficiently suppressing an increase in motor temperature due to the transmission of frictional heat when a disc brake is operated.

  The invention according to claim 1 for solving the above-mentioned problems includes a case attached to a vehicle via a suspension device, a motor provided in the case and including a stator and a rotor, and rotatable in the case. An output shaft having one end connected to the rotor via a reduction gear and the other end connected to the wheel via a wheel hub, a disc brake attached adjacent to the case, and the wheel And a brake rotor disk coupled to a hub and provided so as to be clamped by a brake pad of the disk brake. In a wheel driving device that drives the wheel by the motor, oil injected into the case, and oil An oil cooler for cooling the oil, and the oil cooled by the oil cooler to the motor side end of the output shaft An oil pump and the output shaft cooling oil passage for supplying the, characterized in that it comprises an oil amount adjusting means for increasing the amount of oil supplied to the output shaft cooling oil passage upon actuation of the disc brake.

  The invention according to claim 2 is the wheel drive device according to claim 1, further comprising a rotor shaft that is rotatably supported by the case and is inserted into the inner peripheral side of the rotor and connected to the rotor. The output shaft cooling oil passage includes a rotor shaft oil passage provided at a shaft center portion in the rotor shaft.

  According to a third aspect of the present invention, in the wheel drive device according to the second aspect, the output shaft and the rotor shaft are arranged side by side in the axial direction, and are opened on the motor side end surface of the output shaft on the rotor shaft side. A recess is formed, and the outlet of the output shaft cooling oil passage is located at an inner peripheral portion of the recess.

  The invention according to claim 4 is the wheel drive device according to any one of claims 1 to 3, further comprising a stator cooling oil passage that connects the oil pump and the stator, and is cooled by the oil cooler. The oil is configured to be supplied to the stator via the stator cooling oil passage.

  According to a fifth aspect of the present invention, in the wheel drive device according to any one of the first to fourth aspects, the oil amount adjusting means includes a movable body that is movable in the vehicle front-rear direction, and the movable body is arranged in the rear of the vehicle. A switching valve having a biasing means for biasing to the side, and the output shaft cooling oil when the moving body is switched to the vehicle front side compared to when the moving body is switched to the vehicle rear side. The oil supplied to the road is configured to be increased.

  According to the first aspect of the present invention, as will be described below, it is possible to efficiently suppress an increase in the motor temperature due to the transmission of frictional heat when the disc brake is operated.

  The wheel drive device of the present invention increases the amount of oil supplied to the output shaft cooling oil passage when the disc brake is operated by the oil amount adjusting means. As a result, the cooling performance for the output shaft, which is the transmission path of the frictional heat, is enhanced, so that the amount of heat transmitted to the motor is reduced and the increase in the motor temperature is suppressed. Moreover, since the oil is oil cooled by an oil cooler, a high cooling effect can be obtained.

  Note that “increase” the amount of oil supplied to the output shaft cooling oil passage when the disc brake is operating does not supply oil to the output shaft cooling oil passage when the disc brake is not operating, Some of them sometimes do this, and some supplies oil to the output shaft cooling oil passage to some extent when the disc brake is not operated, and increases the amount when the disc brake is operated.

  Regardless of the operating state of the disc brake, a high cooling effect can be obtained even if oil corresponding to the above increase is always supplied to the oil passage for cooling the output shaft. However, when the disc brake that does not generate frictional heat is not operating, the cooling of the output shaft, which is the intrusion route, is a wasteful consumption of cooling oil, resulting in improper oil distribution and an increase in the size of the oil cooler. There is a risk of increasing the capacity. The present invention promotes the cooling of the disc brake when the output shaft must be actively cooled, so that the cooling oil is consumed efficiently, the oil distribution is optimized, and the oil cooler is compact. Downsizing and capacity reduction.

  According to the second aspect of the present invention, since the oil passage for cooling the output shaft passes through the rotor, the effect of cooling the rotor from the inside can be obtained, and the cooling performance of the motor can be further improved.

  According to the invention of claim 3, the recess formed in the motor side end surface of the output shaft acts like a saucer that receives the oil supplied from the output shaft cooling oil passage, so that the oil tends to stay there. The cooling performance of the output shaft can be further enhanced. That is, the cooling performance of the motor can be further improved.

  According to the invention of claim 4, since the oil cooled by the oil cooler cools the stator via the stator cooling oil passage, the temperature rise of the motor due to heat generation of the stator can be effectively suppressed.

  Further, the structure of the wheel drive device can be simplified by combining the oil pump that supplies oil to the output shaft cooling oil passage and the oil pump that supplies oil to the stator cooling oil passage.

  Furthermore, the oil amount adjusting means can increase the oil supply ratio to the stator cooling oil passage when the disc brake is not operated, and increase the oil supply ratio to the output shaft cooling oil passage when the disc brake is operated. , Efficient oil distribution can be performed.

  According to the fifth aspect of the present invention, the switching valve that is the oil amount adjusting means can be switched using the inertial force (so-called deceleration G) that accompanies vehicle deceleration when the disc brake is activated. Therefore, the oil amount adjusting means can have a simple structure.

  The switching valve may be of any type, but for example, a spool valve is suitable. At this time, the moving body becomes a spool. When the disc brake is not in operation (equivalent to steady running or acceleration), the moving body of the switching valve is switched to the vehicle rear side by the urging force of the urging means. Accordingly, the amount of oil supplied to the output shaft cooling oil passage is not increased. When the disc brake is activated and the deceleration G acts on the vehicle, the deceleration G also acts on the moving body of the switching valve. When the deceleration G overcomes the urging force of the urging means, the moving body is switched to the vehicle front side. . Then, the amount of oil supplied to the output shaft cooling oil passage is increased, and cooling of the output shaft is promoted.

  The switching timing of the switching valve can be appropriately set by adjusting the mass of the moving body and the biasing force of the biasing means in consideration of the amount of frictional heat generated when the disc brake is operated and the magnitude of the deceleration G.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a wheel drive device 1 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the wheel drive device 1. In FIG. 1, the upper part of the figure indicates the upper part of the vehicle, and in FIG. 2, the upper part of the figure indicates the front part of the vehicle. 1 and 2 show the left front wheel, the same configuration is provided for all the drive wheels.

  The wheel drive device 1 includes a case 3 attached to a vehicle via a suspension device 130 (an upper strut assembly 131 and a lower lower arm 132 shown in FIG. 1 and a rear tie rod 133 shown in FIG. 2), And one end of which is connected to the rotor 22 via the planetary gear 30 (reduction gear) and the other end is connected to the wheel 120 via the wheel hub 85. The output rotor 80, a disc brake 90 (shown in FIG. 2) mounted adjacent to the case 3, and a brake rotor connected to the wheel hub 85 and provided so as to be clamped by a brake pad 93 of the disc brake 90 A disk 87.

  The motor 20 mainly includes a stator 21 and a rotor 22. The stator 21 is formed by winding a coil around a substantially cylindrical stator core, and is fixed to the case 3. The rotor 22 is a substantially cylindrical member provided on the inner peripheral side of the stator 21. A rotor shaft 25 that is rotatably supported by the case and is inserted into the inner peripheral side of the rotor 22 and connected to the rotor 22 is provided. A rotor shaft oil passage 27 penetrating the rotor shaft 25 in the axial direction is formed in the axial center portion of the rotor shaft 25. By passing a predetermined current through the coil of the stator 21, the rotor 22 is rotated by electromagnetic force, and the driving force is output from the rotor shaft 25.

  The planetary gear 30 is a speed reducer that decelerates the rotation of the rotor 22 (rotor shaft 25) and transmits it to the output shaft 80. The main structure of the planetary gear 30 includes a sun gear 31 provided at the center, pinion gears 32 meshed with the sun gear 31 and arranged at a plurality of radial equidistant positions from the sun gear 31, and a ring-shaped member coaxial with the sun gear 31. The ring gear 33 meshes with the pinion gears 32 on the inner peripheral surface thereof, and the carrier 34 that supports the pinion gears 32 while maintaining their relative positions.

  The sun gear 31 is connected to the rotor shaft 25. The carrier 34 is connected to the output shaft 80. The ring gear 33 is fixed to the case 3.

  The output shaft 80 is provided on the opposite side of the motor 20 with the planetary gear 30 interposed therebetween. The output shaft 80 and the rotor shaft 25 are juxtaposed in the axial direction. The base end side (motor side) of the output shaft 80 is enlarged in diameter, and a concave portion 80a that opens to the rotor shaft 25 side is formed on the end surface. And the front-end | tip of the rotor shaft 25 enters into the recessed part 80a, and it arrange | positions so that the exit of the rotor shaft oil path 27 may be located in the inner periphery of the recessed part 80a.

  The front end side of the output shaft 80 protrudes from the case 3 and is connected to the wheel 120. Specifically, the distal end side of the output shaft 80 is fitted into a substantially cylindrical wheel hub 85 having a flange portion, and is fixed by a nut 81. A wheel disc 121 is fixed to a flange portion of the wheel hub 85 by a bolt / nut 103 together with a substantially disc-shaped brake rotor disc 87. The outer periphery of the wheel disc 121 is fitted into the inner peripheral surface of the tire 122. The wheel disc 121 and the tire 122 are integrated to form the wheel 120. With the above configuration, the output shaft 80, the wheel hub 85, the brake rotor disk 87, and the wheel 120 rotate integrally.

  As shown in FIG. 2, a disc brake 90 is provided at the front portion of the brake rotor disc 87. The disc brake 90 includes a brake pad 93 that holds the brake rotor disc 87 from both the front and back surfaces, a brake caliper 91 that supports the brake pad 93, and a brake piston 92 that moves the brake pad 93 via the brake caliper 91.

  Next, the lubrication and cooling system of the wheel drive device will be described. A predetermined amount of oil is injected into the case 3. The oil forms an oil sump at the bottom of the case 3.

  An oil pump 50 is provided on the side opposite to the planetary gear 30 across the motor 20. The oil pump 50 sucks up the oil from the oil reservoir by the rotation of the oil pump rotor connected to the rotor shaft 25, boosts the oil, and discharges it to the oil passage for lubrication or cooling.

  FIG. 3 is a right side view of FIG. In the illustrated state, the right side is the front of the vehicle. An oil passage 57 extending downward in the case 3 is connected to the suction port 58 of the oil pump 50, and an oil strainer 55 that opens near the bottom of the oil reservoir is attached to the lower end of the oil passage 57.

  One end of an oil passage 62 (pipe) led out of the case 3 is connected to the discharge port 61 of the oil pump 50, and an introduction port 63 a of an oil cooler 63 is connected to the other end of the oil passage 62. . The oil cooler 63 is a device for cooling the oil by heat exchange, and a thin tube is disposed between the oil inlet 63a and the outlet 63b. While the oil passes through the narrow tube, heat exchange between the oil and the outside air is performed on the wall surface of the narrow tube. The oil cooler 63 is disposed in front of the case 3 where the traveling wind W is likely to hit when the vehicle moves forward so that heat exchange is promoted.

  One end of an oil passage 64 (pipe) is connected to the outlet 63 b of the oil cooler 63, and the other end of the oil passage 64 is connected to a switching valve 70 housed in the case 3. Although the detailed structure of the switching valve 70 will be described in detail later, the switching valve 70 of this embodiment is an alternative switching type, and the oil supplied from the oil passage 64 is oil passage 65 (pipe) or oil passage 78. It is a valve which leads to either one of these.

  One end of the oil passage 65 is connected to the switching valve 70, and the other end is connected to the oil passage 66 at the top of the case 3. As shown in FIG. 1, the oil passage 66 extends inside the case 3 in the axial direction above the stator 21. The case 3 is formed with oil holes 67 and 68 having one end opened to the oil passage 66 and the other end opened to the inside of the case 3. The oil hole 67 allows communication between the oil passage 66 and the upper portion of the stator core of the stator 21, and the oil hole 68 allows communication between the oil passage 66 and the upper portion of the coil of the stator 21. The oil passage 62 from the discharge port 61 of the oil pump 50 to the stator 21, the oil cooler 63, the oil passage 64, the switching valve 70, the oil passages 65 and 66, and the oil holes 67 and 68, as a whole, form the stator cooling oil passage 69. Form. The stator cooling oil passage 69 is an oil supply oil passage for preferentially cooling the stator 21.

  On the other hand, as shown in FIG. 2, the oil passage 78 has one end connected to the switching valve 70 and the other end connected to the rotor shaft oil passage 27 via the case 3. The oil passage 62, the oil cooler 63, the oil passage 64, the switching valve 70, the oil passage 78, and the rotor shaft oil passage 27 extending from the discharge port 61 of the oil pump 50 to the vicinity of the recess 80 a of the output shaft 80 are for cooling the output shaft as a whole. An oil passage 79 is formed. The output shaft cooling oil passage 79 is an oil supply oil passage for preferentially cooling the output shaft 80. Of the output shaft cooling oil passage 79, the passage from the discharge port 61 of the oil pump 50 to the switching valve 70 is shared with the stator cooling oil passage 69.

  4A and 4B are diagrams schematically showing the structure of the switching valve 70 and the oil passage around the switching valve 70. FIG. 4A shows a state when the disc brake is not operated, and FIG. 4B shows a state when the disc brake is operated. . Hereinafter, the structure of the switching valve 70 will be described with reference to FIG. In addition, about the switching valve 70 shown in FIG. 4, the upper part of a figure shows a vehicle front, and the downward direction of a figure shows a vehicle rear.

  The switching valve 70 is a spool and mainly includes a cylinder portion 71 (a part of the case 3), a spool 72, a spring 73, and a retainer 74. The cylinder portion 71 has a bottomed cylindrical shape with the vehicle longitudinal direction as an axis. A first port 75 communicating with the oil passage 64 and a second port 76 communicating with the oil passage 65 are provided on the side surface of the cylinder portion 71. A third port 77 communicating with the oil passage 78 is provided on the rear end surface of the cylinder portion 71.

  A spool 72 as a moving body is provided in the cylinder portion 71 so as to be movable back and forth. The spool 72 mainly includes a land portion 72a that is substantially the same diameter as the inner diameter of the cylinder portion 71 and that is in sliding contact with the inner peripheral portion of the cylinder portion 71, a shaft portion 72b that projects forward from the land portion 72a and has a smaller diameter than the land portion 72a. Consists of. The shaft portion 72b serves as a guide for a spring 73, which will be described later, and also serves as a stopper when the spool 72 moves forward.

  The front opening of the cylinder portion 71 is closed by a retainer 74. Between the land portion 72a of the spool 72 and the retainer 74, there is provided a spring 73 (biasing means) that constantly biases the spool 72 rearward.

  When the disk brake shown in FIG. 4 (a) is not operated (corresponding to the steady running or acceleration of the vehicle, the same applies hereinafter), the spool 72 is switched to the vehicle rear side as shown in the figure by the urging force of the spring 73. Yes. At this time, the third port 77 is closed by the rear end of the land portion 72a, and the first port 75 and the second port 76 communicate with each other.

  On the other hand, since the vehicle decelerates when the disc brake shown in FIG. 4B is operated, the deceleration G is applied to the spool 72. That is, a forward inertial force G1 acts. The mass of the spool 72 and the urging force of the spring 73 are set so that the inertial force G1 overcomes the urging force of the spring 73 when the deceleration is greater than a predetermined value, and the spool 72 is switched to the front side of the vehicle as shown in the figure. (In this specification, “when the disc brake is activated” is also used to mean that the disc brake is operated with such a strong braking force). When the spool 72 is switched to the vehicle front side, the communication between the first port 75 and the second port 76 is blocked by the land portion 72a, and the first port 75 and the third port 77 are connected.

  As described above, the switching valve 70 automatically determines whether or not the disc brake 90 is operated depending on whether or not the inertial force G1 of a predetermined value or more is applied, and determines the balance between the inertial force G1 and the biasing force of the spring 73. The spool 72 is automatically switched. Therefore, no other actuator such as a sensor or a solenoid valve is required, and the structure is simple.

  Next, the oil supply mode when the spool 72 is switched to the vehicle rear side (FIG. 4A) will be described. The oil 11 in the oil reservoir 10 is sucked up by the oil pump 50 via the oil strainer 55 and the oil passage 57. At this time, foreign matter or the like is captured by the oil strainer 55, and the oil 11 is purified. The oil 11 pressurized and discharged by the oil pump 50 is cooled by the oil cooler 63 via the oil passage 62. The cooled oil 11 is guided to the second port 76 from the first port 75 of the switching valve 70 through the oil path 64 and further to the oil path 65. That is, the oil 11 is supplied to the stator cooling oil passage 69. The oil is not supplied to the rotor shaft oil passage 27 from the switching valve 70, but is slightly supplied due to a leak from the oil pump 50 or the like.

  On the other hand, when the spool 72 is switched to the vehicle front side (FIG. 4B), the oil supply mode is as follows. The process from the oil reservoir 10 to the first port 75 of the switching valve 70 is the same as in FIG. The oil 11 guided to the first port 75 is guided to the third port 77 and further guided to the rotor shaft oil path 27 via the oil path 78. That is, the oil 11 is supplied to the output shaft cooling oil passage 79.

  Next, the operation of the wheel drive device 1 will be described. First, the rotation operation of each axis will be described with reference to FIG. The rotor shaft 25 of the motor 20 rotates counterclockwise when viewed from the wheel 120 side when moving forward. The sun gear 31 of the planetary gear 30 connected to the rotor shaft 25 also rotates counterclockwise. Since the pinion gear 32 meshes with the sun gear 31, the pinion gear 32 rotates clockwise around the axis. However, since the ring gear 33 is fixed to the case 3, the shaft position rotates counterclockwise. That is, the carrier 34 rotates counterclockwise. At this time, the rotation speed of the carrier 34 is lower than the rotation speed of the rotor shaft 25, and the torque is amplified (deceleration action). The output shaft 80 and the wheel 120 integral with the carrier 34 also rotate counterclockwise, and the vehicle moves forward. When the vehicle moves backward, the rotation direction of each part is opposite to the above-mentioned directions by rotating the rotor 22 in the reverse direction (right rotation).

  Next, the operation of the disc brake 90 will be described with reference to FIG. When the driver steps on the foot brake (not shown), the brake piston 92 is activated, and the brake pad 93 supported by the brake caliper 91 sandwiches and presses the brake rotor disk 87. Although the brake rotor disk 87 rotates integrally with the wheel 120, a strong frictional force is generated by being sandwiched and pressed by the brake pad 93, and a braking force that suppresses the rotation of the wheel 120 is obtained by the frictional force.

  Next, the flow of oil and lubrication / cooling of each part will be described. FIG. 5 is an explanatory diagram showing the flow of oil with arrows when the disc brake is not in operation, with the switching valve 70 in the state of FIG. At this time, the oil that has passed through the switching valve 70 as described above is supplied to the oil passage 65 of the stator cooling oil passage 69. Thereafter, the oil passes through the oil passage 66 and falls from the oil holes 67 and 68 to the stator 21 to cool it. Therefore, the temperature rise of the motor 20 due to the heat generation of the stator 21 is effectively suppressed. The oil that has cooled the stator 21 subsequently drops while being dispersed in each part, and after cooling the other members and lubricating the rotating member, the oil is finally returned to the oil reservoir at the bottom of the case 3.

  FIG. 6 is an explanatory diagram showing the flow of oil and the state of transmission of frictional heat generated by the disc brake 90 when the disc brake is activated, with arrows, when the switching valve 70 is in the state of FIG. The oil flow is indicated by a solid line (partially hidden line), and the state of frictional heat transfer is indicated by a broken line. At this time, the oil that has passed through the switching valve 70 as described above is supplied from the oil passage 78 of the output shaft cooling oil passage 79 to the rotor shaft oil passage 27. Then, the oil is ejected from the tip of the rotor shaft oil passage 27 and hits the recess 80 a of the output shaft 80 to cool the output shaft 80. The recess 80a acts like a tray that receives the oil, and the oil easily stays there, so that the cooling performance is further improved. The oil that has cooled the output shaft 80 subsequently drops while being dispersed in each part, and after cooling the other members and lubricating the rotating member, the oil is finally returned to the oil reservoir at the bottom of the case 3.

  On the other hand, the frictional heat generated between the brake pad 93 and the brake rotor disk 87 is distributed and transmitted to each part, but a part thereof is transmitted to the output shaft 80 via the wheel hub 85 and directed to the motor 20. . However, since the recess 80a is actively cooled by the oil supplied from the rotor shaft oil passage 27, the heat transfer toward the motor 20 side is greatly suppressed. Therefore, the temperature rise of the motor 20 due to the transmission of frictional heat is effectively suppressed.

  In addition, since the rotor shaft oil passage 27 is formed inside the rotor 22, the oil flowing through the rotor shaft oil passage 27 also cools the rotor 22 itself. Thereby, the cooling property of the motor 20 is further enhanced.

  Next, another embodiment will be described. In the following embodiments, descriptions of common parts with the first embodiment are omitted, and differences from the first embodiment are mainly described. In FIGS. 7 and 8 referred to in the following embodiment, the same or equivalent members as those in the first embodiment referring to FIGS. .

  7A and 7B are diagrams schematically showing the structure of the switching valve 70a and the oil passage around the switching valve 70a in the second embodiment, where FIG. 7A is a state when the disc brake is not operated, and FIG. Indicates the state of the hour.

  In the first embodiment, the switching valve 70 is an alternative switching type, whereas the present embodiment is different in that the switching valve 70a is an add-on type. That is, the switching valve 70a always supplies oil to the stator cooling oil passage 69 regardless of whether or not the disc brake 90 is operated, and distributes a part thereof to the output shaft cooling oil passage 79 when the disc brake is operated. It is configured as follows.

  A shallow groove 71a that connects the first port 75 and the second port 76 is formed in the cylinder portion 71 of the switching valve 70a.

  The supply form of the oil 11 when the disc brake is not shown in FIG. 7A is the same as that of the first embodiment, and the oil 11 cooled by the oil cooler 63 is supplied to the stator cooling oil passage 69.

  The supply form of the oil 11 when the disc brake shown in FIG. 7B is operated is as follows. As in the first embodiment, when the spool 72 is switched forward, the first port 75 and the third port 77 communicate with each other, and oil is supplied to the output shaft cooling oil passage 79. On the other hand, the communication path from the first port 75 to the second port 76 is largely blocked by the land portion 72 a of the spool 72. However, since communication is ensured in the groove 71a, a certain amount of oil is supplied to the stator cooling oil passage 69.

With this configuration, the stator 21 can be continuously cooled while giving priority to the cooling of the output shaft 80 when the disc brake is operated. The oil distribution ratio between the stator cooling oil passage 69 and the output shaft cooling oil passage 79 at this time can be set to an appropriate ratio by appropriately adjusting the width and depth of the groove 71a.

  FIG. 8 is a diagram schematically showing the structure of the switching valve 70b and the oil passage around the switching valve 70b in the third embodiment, where (a) is a state when the disc brake is not operated, and (b) is a disc brake operation. Indicates the state of the hour.

  While the switching valve 70 is an alternative switching type in the first embodiment and an add-on type in the second embodiment, the present embodiment is different in that the switching valve 70b is a flow rate adjustment type. That is, the switching valve 70b always supplies oil to the stator cooling oil passage 69 and the output shaft cooling oil passage 79 regardless of whether or not the disc brake 90 is operated, and when the disc brake is operated, the output shaft cooling oil passage is supplied. 79 is configured to increase the flow distribution to 79.

  A shallow groove 71a that connects the first port 75 and the second port 76 is formed in the cylinder portion 71 of the switching valve 70b (similar to the second embodiment). The cylinder portion 71 is formed with a shallow groove portion 71 b that communicates the first port 75 and the third port 77.

  The supply form of the oil 11 when the disc brake shown in FIG. 8A is not operated is as follows. As in the first embodiment, when the spool 72 is switched rearward, the first port 75 and the second port 76 communicate with each other, and the oil 11 is supplied to the stator cooling oil passage 69. On the other hand, the communication path from the first port 75 to the third port 77 is largely blocked by the land portion 72 a of the spool 72. However, since communication is ensured in the groove 71b, a certain amount of oil is supplied to the output shaft cooling oil passage 79.

  8 (b) is the same as that of the second embodiment shown in FIG. 7 (b) when the disc brake is operated, and the oil is mainly supplied to the output shaft cooling oil passage 79. However, a certain amount of oil is supplied to the stator cooling oil passage 69.

  By configuring in this way, cooling of the output shaft 80 can be continued while giving priority to cooling of the stator 21 when the disc brake is not operated, and priority is given to cooling of the output shaft 80 when the disc brake is operated, The stator 21 can also be continuously cooled. The oil distribution ratio between the stator cooling oil passage 69 and the output shaft cooling oil passage 79 at this time can be set to an appropriate ratio by appropriately adjusting the width and depth of the groove 71a and the groove 71b. .

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said each embodiment, It can change suitably in a claim.

  For example, in each of the above-described embodiments, the switching valves 70, 70a, and 70b provided with the moving body (spool 72) and the urging means (spring 73) are used as the oil amount adjusting means. Other mechanical switching valves such as a valve type may be used. A ball or the like may be used as the moving body in that case.

  Further, as the means for moving the moving body, in each of the above embodiments, the inertial force G1 at the time of operating the disc brake is used. However, this is not always necessary, and other sensors (brake sensors, etc.), actuators (solenoid valves), etc. are used. May be. When the inertia force G1 at the time of disc brake operation is not used, the installation posture of the oil amount adjusting means can be freely set without being limited to the vehicle front-rear direction.

  In the above embodiments, the separate oil cooler 63 is provided, but the present invention is not necessarily limited thereto. For example, a simple oil cooler that is cooled by the traveling wind W between the oil reservoir of the case 3 and the case wall surface may be used.

It is a longitudinal cross-sectional view of the wheel drive device which concerns on one Embodiment of this invention. It is a cross-sectional view of the wheel drive device. It is a right view of FIG. It is a figure which shows typically the structure of a switching valve, and the oil path around a switching valve, Comprising: (a) shows the state at the time of disc brake non-operation, (b) shows the state at the time of disc brake operation. It is explanatory drawing which shows the flow of the oil at the time of a disc brake non-operation by the arrow. It is explanatory drawing which shows the flow of the oil at the time of a disc brake action | operation, and the transmission state of the frictional heat which generate | occur | produced with the disc brake by the arrow. It is a figure which shows typically the structure of the switching valve in 2nd Embodiment, and the oil path around a switching valve, Comprising: (a) shows the state at the time of disc brake non-operation, (b) shows the state at the time of disc brake operation. . It is a figure which shows typically the structure of the switching valve in 3rd Embodiment, and the oil path around a switching valve, Comprising: (a) shows the state at the time of disc brake non-operation, (b) shows the state at the time of disc brake operation. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel drive device 3 Case 11 Oil 20 Motor 21 Stator 22 Rotor 25 Rotor shaft 27 Rotor shaft oil path 30 Planetary gear (reduction gear)
50 Oil pump 63 Oil cooler 69 Oil passage for stator cooling 70 Switching valve (oil amount adjusting means)
72 Spool (moving body)
73 Spring (biasing means)
79 Output shaft cooling oil passage 80 Output shaft 80a Recess 87 Brake rotor disc 90 Disc brake 93 Brake pad 85 Wheel hub 120 Wheel

Claims (5)

A case attached to the vehicle via a suspension,
A motor provided in the case and including a stator and a rotor;
An output shaft provided rotatably in the case, one end of which is connected to the rotor via a speed reducer and the other end of which is connected to a wheel via a wheel hub;
A disc brake mounted adjacent to the case;
A brake rotor disk connected to the wheel hub and provided to be clamped by a brake pad of the disk brake;
In the wheel driving device that drives the wheel by the motor,
Oil injected into the case,
An oil cooler for cooling the oil;
An oil pump for supplying the oil cooled by the oil cooler to the motor side end surface of the output shaft and an oil passage for cooling the output shaft;
An oil amount adjusting means for increasing the amount of oil supplied to the output shaft cooling oil passage when the disc brake is operated. The rotor is rotatably supported by the case, and includes a rotor shaft that is inserted into the inner peripheral side of the rotor and connected to the rotor.
2. The wheel drive device according to claim 1, wherein the output shaft cooling oil passage includes a rotor shaft oil passage provided at a shaft center portion in the rotor shaft. The output shaft and the rotor shaft are arranged side by side in the axial direction, and a recess opening to the rotor shaft side is formed on the motor side end surface of the output shaft,
The wheel driving device according to claim 2, wherein an outlet of the oil passage for cooling the output shaft is located at an inner peripheral portion of the recess. A stator cooling oil passage connecting the oil pump and the stator;
4. The structure according to claim 1, wherein the oil cooled by the oil cooler is configured to be supplied to the stator via the stator cooling oil passage. 5. Wheel drive device. The oil amount adjusting means is a switching valve including a moving body that is movable in the vehicle front-rear direction and an urging means that urges the moving body toward the vehicle rear side.
When the moving body is switched to the vehicle front side, the amount of oil supplied to the output shaft cooling oil passage is increased compared to when the vehicle is switched to the vehicle rear side. The wheel drive device according to any one of claims 1 to 4, wherein

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