JP2017131078A - Cooling structure of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure of a motor, capable of efficiently cooling a coil of a stator by cooling oil diffused from a rotary shaft of a rotor and capable of improving output of the motor.SOLUTION: The coil of a stator 9 is composed of a plurality of individual coils 33 formed on respective tooth portions of a stator core. Each individual coil 33 is composed of a coil bobbin 34 surrounding an outer periphery of the tooth portion and a winding 35 wound around the coil bobbin 34. A shaft center oil feeding passage 56 for feeding cooling oil through a shaft center of a rotary shaft 6 and a discharge oil passage 60 connected to the shaft center oil feeding passage 56 to discharge the cooling oil to an inner space S of a housing 8 are formed. The coil bobbin 34 has a protrusion 34ba protruded to an outer diameter end of a motor diameter direction at least in a motor shaft direction as compared with a winding diameter of the winding 35, and a repelling face 37 for repelling the cooling oil discharged from the discharge oil passage 60 and diffused to the outer diameter side of the motor diameter direction through the inner space S to the winding 35 is formed on the protrusion 34ba.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling structure for a motor such as an in-wheel motor.

  Motors are widely used in vehicles, industrial machines, etc., and are required to be small, light, high efficiency, and high output. On the other hand, the output of the motor is limited by the temperature of the motor. Therefore, in order to improve the output of the motor, it is important to suppress the temperature rise of the motor, in particular, the temperature rise of the stator coil as a heat source.

The following proposals have been made as a method for cooling the coil.
(1) Patent Document 1
In this proposal, a notch portion is provided in an insulating bobbin that covers the periphery of the stator core and is wound with a winding ("conductor" in Patent Document 1), and the winding exposed in the notch and the winding surface of the insulating bobbin The impregnating material is dropped in between. Instead of cooling with oil, the cooling performance is improved by spreading the impregnating material over the entire coil.

(2) Patent Document 2
In this proposal, a through hole for passing cooling oil through a bobbin (“supply hole” in Patent Document 2) is provided so that the cooling oil supplied from the outside is spread over the entire coil.

(3) Patent Document 3
In this proposal, cooling oil ("oil" in Patent Document 3) diffused in the radial direction from the axis of the rotor is guided to a stator (particularly a coil) by a guide surface provided on the inner wall of the casing, and the coil is Cooling.

JP 2010-213391 A JP 2010-239775 A JP 2010-172069 A

  In Patent Document 1, it is described that a varnish is spread over the entire stator including the gap of the coil by providing a groove in an insulating bobbin and utilizing a capillary phenomenon. However, there is no mention of cooling using a cooling medium such as oil or water.

  Patent Document 2 describes that a coil is efficiently cooled with cooling oil supplied from the outside of a motor by providing a through-hole in a bobbin. However, there is no mention of cooling the coil using cooling oil supplied from the inside of the motor.

  In general, in order to improve the cooling performance of the motor, a sufficiently cooled cooling medium may be supplied to the motor. However, when the motor is an in-wheel motor used for the undercarriage of the vehicle, it is indispensable to reduce the size and weight, and it is difficult to install a pipe for guiding a cooling medium to the motor outside the motor.

  Therefore, in-wheel motors employ an internal circulation system in which a cooling medium is circulated inside the motor. For example, as shown in FIG. 12, the internal circulation system cools the stator core 30 and the coil 31 of the stator 9 by diffusing a cooling medium from the rotating shaft 6 of the rotor 10 into the housing 8 of the motor 1. In addition, as an internal circulation system, there is a configuration in which the stator core 30 and the coil 31 of the stator 9 are cooled by scraping or splashing the cooling medium with a centrifugal force accompanying the rotation of the rotor 10. In any configuration, it is unclear whether all of the cooled or splashed cooling medium or the diffused cooling medium reaches the stator core 30 and the coil 31 of the stator 9. FIG. 12 shows a motor drive device in which the motor 1, the speed reducer 2, and the wheel bearing 5 are combined.

  Patent Document 3 is a proposal in which an internal circulation system is applied to an in-wheel motor. Cooling oil supplied from the outside of the motor is discharged from an oil passage provided on the rotating shaft of the rotor to the inside of the casing. It is described that the stator is uniformly cooled by guiding the cooled cooling oil to a coil along a concave curved guide surface provided on the inner wall of the casing. This patent document 3 is applied to a motor that does not use a bobbin for winding a coil around a stator core.

  When the coil winding method is concentrated winding, a coil bobbin is used to provide insulation between the coil and the stator core. When the configuration of Patent Document 3 is applied to a motor using a coil bobbin in this way, the path of the cooling oil guided by the guide surface of the inner wall of the casing is obstructed by the coil bobbin, so that the cooling oil does not reach the coil well, and the stator There is a concern that the cooling of the water cannot be sufficiently performed.

  An object of the present invention is applied to a motor using a coil bobbin, and can cool a stator coil efficiently with cooling oil diffused from a rotating shaft of the rotor, thereby cooling the motor capable of improving the output of the motor. Is to provide a structure.

A cooling structure for a motor of the present invention includes a stator including a stator core and a coil, a housing that covers and fixes the stator, a rotating shaft that is rotatably supported by the housing via a plurality of bearings, and a rotating shaft. The stator includes an integrally fixed rotor and an oil cooling type cooling device, the stator core has a plurality of teeth arranged radially around the axis of the rotating shaft, and the coils are provided on the teeth. A plurality of individual coils, and these individual coils are a cooling structure for a motor including a coil bobbin that surrounds the outer periphery of the tooth portion, and a winding wound around the coil bobbin.
The oil cooling type cooling device includes a shaft center oil supply passage that supplies cooling oil through an axis of the rotating shaft, and a discharge that discharges the cooling oil to an internal space of the housing in communication with the shaft center oil supply passage. An oil passage,
Each of the coil bobbins has an overhang portion that protrudes at least in the motor axial direction from the winding diameter of the winding at the outer diameter end in the motor radial direction, and is discharged from the discharge oil passage to the overhang portion. A repellent surface is formed that repels the cooling oil diffused in the inner space of the housing toward the outer diameter side in the motor radial direction toward the winding.

  According to this configuration, the cooling oil is discharged into the internal space of the housing through the axial oil supply passage and the discharge oil passage. The cooling oil discharged to the internal space is diffused to the outer diameter side in the motor radial direction by the centrifugal force accompanying the rotation of the rotor, and then rebounds at the repellent surface at the projecting portion of the coil bobbin and hits the winding. Thereby, since the winding of each individual coil is efficiently cooled, the output of the motor can be improved.

In this invention, the cooling oil is discharged from the discharge oil passage at an angle inclined with respect to the motor shaft direction on the outer diameter side in the motor radial direction and away from the rotor in the motor shaft direction. The discharge oil passage is preferably provided.
As described above, the cooling oil discharged from the discharge oil passage to the internal space of the housing is diffused to the outer diameter side by the centrifugal force accompanying the rotation of the rotor. When the cooling oil is discharged from the discharge oil passage at an angle with respect to the motor axial direction, the cooling oil diffuses smoothly to the outer diameter side in the internal space of the housing.

In the present invention, the coil bobbin includes a central portion around which the winding is wound, and an outer diameter side that protrudes in the motor axial direction from an outer diameter end of the central portion in the motor radial direction and insulates the housing and the winding. A convex portion and an inner diameter side convex portion that protrudes in the motor axial direction from the inner diameter end of the central portion in the motor radial direction and insulates the rotor and the winding, and a part of the outer diameter side convex portion is the It may be an overhang part.
When the coil bobbin has the above-described configuration, the outer diameter side convex portion and the inner diameter side convex portion can prevent the displacement of the winding wound around the central portion of the coil bobbin toward the outer diameter side and the inner diameter side. The housing and the winding can be insulated from each other by the radial convex portion, and the rotor and the winding can be insulated from each other by the radial convex portion.

In the case where the coil bobbin has the above-described configuration, it is preferable that the outer diameter-side convex portion protrudes larger in the motor axial direction than the inner diameter-side convex portion.
If the outer diameter convex part protrudes larger in the motor axial direction than the inner diameter convex part, the cooling oil discharged from the discharge oil passage and diffusing to the outer diameter side is not blocked by the inner diameter side convex part. Since it reaches the radial convex part, the cooling oil can be efficiently guided to the winding of each individual coil.

A cross-sectional shape obtained by cutting the repellent surface of the projecting portion along a plane passing through the axis of the rotating shaft is inclined so as to be positioned on the inner diameter side in the motor radial direction as the distance from the winding in the motor axial direction increases. May be.
In this case, the cooling oil diffused in the inner space of the housing to the motor outer diameter side can be directly repelled by the repellent surface and guided to the winding of each individual coil.

When the overhanging portion has the above-described configuration, the motor radial direction position of the overhanging portion in the motor axial direction is the position of the outer diameter side convex portion side end of the winding wound around the central portion of the coil bobbin. It may be the same as the position in the motor radial direction or on the outer diameter side.
When the motor axial direction front end of the overhanging portion and the outer diameter side convex portion side end of the winding are in the above positional relationship, the overhanging portion does not get in the way when winding the winding around the central portion of the coil bobbin.

In addition, a cross-sectional shape obtained by cutting the repellent surface of the projecting portion along a plane passing through the axis of the rotating shaft is positioned on the outer diameter side in the motor radial direction as the distance from the winding in the motor axial direction increases. It may be inclined.
In this case, the cooling oil that has been diffused into the internal space of the housing and changed its direction upon striking the wall surface of the housing can be repelled by the repellent surface and guided to the winding of each individual coil.

  A cooling structure for a motor of the present invention includes a stator including a stator core and a coil, a housing that covers and fixes the stator, a rotating shaft that is rotatably supported by the housing via a plurality of bearings, and a rotating shaft. The stator includes an integrally fixed rotor and an oil cooling type cooling device, the stator core has a plurality of teeth arranged radially around the axis of the rotating shaft, and the coils are provided on the teeth. These individual coils have a cooling structure comprising a plurality of coil bobbins surrounding the outer periphery of the tooth portion and windings wound around the coil bobbins. An axial oil supply passage for supplying cooling oil through an axial center of the shaft; and a discharge oil passage for discharging the cooling oil to the internal space of the housing in communication with the axial oil supply passage. Has an overhanging portion that protrudes at least in the motor axial direction beyond the winding diameter of the winding at the outer diameter end in the motor radial direction, and is discharged from the discharge oil passage to the overhanging portion of the housing. Since a repelling surface is formed to repel the cooling oil diffused from the inner space to the outer diameter side in the motor radial direction toward the winding, the stator coil is formed by the cooling oil diffused from the rotating shaft of the rotor. Can be efficiently cooled, and the output of the motor can be improved.

It is sectional drawing of the motor drive device which concerns on one Embodiment of this invention. It is the elements on larger scale of FIG. It is sectional drawing of the reduction gear used as the III-III line cross section of FIG. FIG. 4 is a partially enlarged view of FIG. 3. It is the figure which looked at the stator of the motor of the motor drive device from the direction parallel to the motor axis. It is a front view of the individual coil of the stator. It is a perspective view of the same individual coil. It is sectional drawing of the motor drive device which concerns on other embodiment of this invention. It is the elements on larger scale of FIG. It is a front view of the individual coil of the motor of the motor drive device. It is a perspective view of the same individual coil. It is sectional drawing of the conventional motor drive device.

A motor drive apparatus having a motor cooling structure according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the motor drive device includes a motor 1 that drives wheels, a speed reducer 2 that decelerates the rotation of the motor 1, and an input shaft 3 of the speed reducer 2 (referred to as a speed reducer input shaft 3). And a wheel bearing 5 rotated by a coaxial output member 4 and an oil-cooled cooling device R. A reduction gear 2 is interposed between the wheel bearing 5 and the motor 1, and a wheel hub, which is a driving wheel supported by the wheel bearing 5, and the rotating shaft 6 of the motor 1 are connected coaxially. is there. This motor drive device is an in-wheel motor drive device that is partly or wholly disposed in a wheel.

  A suspension (not shown) in the vehicle is connected to the reduction gear housing 7 that houses the reduction gear 2. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle with the motor drive device provided in the vehicle is referred to as the outboard side, and the side closer to the center in the vehicle width direction of the vehicle is referred to as the inboard side. Call it.

  The motor 1 is an IPM motor (so-called embedded magnet type synchronous motor) in which a radial gap is provided between a stator 9 fixed to a motor housing 8 and a rotor 10 fixed to a rotating shaft 6. The motor housing 8 is provided with rolling bearings 11 and 12 that are spaced apart in the axial direction, and the rotating shaft 6 is rotatably supported by the rolling bearings 11 and 12.

  The rotating shaft 6 transmits the driving force of the motor 1 to the speed reducer 2. The rotor 10 includes a rotor core 10 a, a magnet (not shown) disposed in an opening inside the rotor core 10 a, and a fixed body 13 that fixes the rotor core 10 a to the rotating shaft 6. The fixed body 13 is formed integrally with the rotary shaft 6, and has a flange portion 13 a extending radially outward from a portion near the axial center of the rotary shaft 6, and an outboard side from the outer diameter end of the flange portion 13 a. It consists of a cylindrical portion 13b extending to the inboard side and a pair of flange portions 13c, 13c extending from the outboard side end and the inboard side end of the cylindrical portion 13b to the outer diameter side. The rotor core 10a is fixed between the pair of flange portions 13c, 13c of the fixed body 13.

  One end of the reduction gear input shaft 3 extends in the rotation shaft 6 and is spline-fitted with the rotation shaft 6 (including serration fitting; the same applies hereinafter). A rolling bearing 14a is fitted in the cup portion of the output member 4, and the rolling bearing 14b is fitted in a cylindrical connecting member 4a connected via an inner pin 22 fixed to the cup portion. The reduction gear input shaft 3 and the rotary shaft 6 are supported by the rolling bearings 11, 12, 14a, and 14b so as to be rotatable integrally and concentrically. Eccentric portions 15 and 16 are provided on the outer peripheral surface of the speed reducer input shaft 3. These eccentric portions 15 and 16 are provided with a 180 ° phase shift so that the centrifugal force due to the eccentric motion cancels each other. The speed reducer 2 is a cycloid speed reducer having curved plates 17 and 18, a plurality of outer pins 19, and a counterweight 21.

  3 is a cross-sectional view of the speed reducer portion taken along the line III-III in FIG. In the speed reducer 2, two curved plates 17 and 18, each of which is formed by a wavy trochoid curve having a gentle outer shape, are mounted on the eccentric portions 15 and 16 via rolling bearings 85, respectively. A plurality of outer pins 19 for guiding the eccentric movements of the curved plates 17 and 18 on the outer peripheral side are respectively provided inside the reduction gear housing 7, and the plurality of inner pins 22 are provided inside the curved plates 17 and 18. The plurality of circular through holes 89 provided are engaged with each other in an inserted state.

  As shown in an enlarged view in FIG. 4, needle roller bearings 92 and 93 are attached to each outer pin 19 and each inner pin 22. The outer pins 19 are supported at both ends by needle roller bearings 92, the outer rings 92a of these needle roller bearings 92 are fixed to the reducer housing 7, and the outer pins 19 are rotatably supported. In contact with the outer peripheral surface of the curved plates 17 and 18, respectively, to reduce the contact resistance with the outer periphery of each of the curved plates 17, 18. In each inner pin 22, the outer ring 93 a of the needle roller bearing 93 reduces the contact resistance between the inner periphery of each through-hole 89 of each curved plate 17 and 18 and each inner pin 22.

  Therefore, as shown in FIG. 1, the eccentric motion of the curved plates 17 and 18 can be smoothly transmitted to the inner member (rotating wheel) 5a of the wheel bearing 5 as a rotational motion. When the rotating shaft 6 rotates, the curved plates 17 and 18 provided on the speed reducer input shaft 3 that rotates integrally with the rotating shaft 6 perform an eccentric motion. At this time, the outer pin 19 is engaged so as to be in rolling contact with the outer peripheral surfaces of the curved plates 17 and 18 that are eccentrically moved, and the curved plates 17 and 18 are connected to the inner pin 22 and the through hole 89 (FIG. 4). Due to the engagement, only the rotational motion of the curved plates 17 and 18 is transmitted as rotational motion to the output member 4 and the inner member 5a of the wheel bearing 5. The rotation of the inner member 5a is decelerated with respect to the rotation of the rotating shaft 6.

  The wheel bearing 5 is a double-row angular contact ball bearing in which a ball is incorporated between the inner member 5a and the outer member 5b. The outer member 5b is bolted to the speed reducer housing 7 by a flange 5c. The inner member 5a is spline-fitted (including serration fitting) to the output member 4. The rotational motion transmitted to the inner member 5a is transmitted to the tire from a wheel mounting flange 5d provided on the outer peripheral surface of the inner member 5a on the outboard side.

  FIG. 5 is a view of the stator 9 of the motor as viewed from a direction parallel to the motor axis. As shown in FIG. 5, the stator 9 includes a stator core 30 and a coil 31. The stator core 30 is made of a magnetic material such as an iron-based material, and a plurality of tooth portions 30b protrude from the annular portion 30a toward the inner diameter side. The plurality of tooth portions 30b are arranged radially around the axis of the rotary shaft 6 (FIG. 1). The shape of the cross section obtained by cutting the tooth portion 30b along a plane perpendicular to the radial direction is, for example, a rectangle. The stator core 30 has an annular portion 30a fitted to the inner peripheral surface of the motor housing 8 (FIG. 1), and the annular portion 30a is fastened and fixed in the axial direction by a bolt (not shown).

  The coil 31 has a concentrated winding type and includes a plurality of individual coils 33 wound around the respective tooth portions 30 b of the stator core 30. 6 is a front view of each individual coil, and FIG. 7 is a perspective view thereof. Each individual coil 33 includes a plurality of coil bobbins 34 provided so as to surround the outer periphery of the tooth portion 30 b and a winding 35 wound around the coil bobbin 34. The coil bobbin 34 is made of an insulating material such as a resin material. 6 and 7 also show the teeth 30b of the stator core 30.

  The coil bobbin 34 includes a cylindrical central portion 34a having a through-hole 36 (shown in FIG. 6) having a rectangular cross section into which the tooth portion 30b of the stator core 30 is inserted, and an outer diameter end of the central portion 34a in the motor radial direction. Two outer-diameter-side convex portions 34b projecting from both sides in the motor axial direction (upper end in FIG. 6), and both ends in the motor axial direction from the inner diameter end (lower end in FIG. 6) of the central portion 34a in the motor radial direction. It consists of two inner diameter side convex portions 34c each projecting. The outer-diameter side convex portion 34b projects larger in the motor shaft direction than the inner-diameter side convex portion 34c, and the projecting portion is an overhang portion 34ba. The overhang portion 34ba projects at least in the motor axial direction from the winding diameter of the winding 35.

  The projecting portion 34ba of the coil bobbin 34 has a shape that is inclined so as to be positioned on the inner diameter side in the motor radial direction as it goes to the tip side. A flat repellent surface 37 is formed on the inner diameter surface of the overhang portion 34ba. An inclination angle θ1 (FIG. 6) of the repellent surface 37 with respect to the motor axis is, for example, 15 ° or less. Thus, the overhanging portion 34ba is inclined so as to be positioned on the inner diameter side in the motor radial direction as it goes away from the winding 35, that is, away from the winding 35, but at the base end of the overhanging portion 34ba 38, the motor radial direction position of the overhang portion 34ba in the motor axial direction tip P is the motor radial direction of the outer diameter side convex portion side end of the winding 35 wound around the central portion 34a of the coil bobbin 34. It is the same as the position or on the outer diameter side. In the case of the example in the figure, the motor radial direction position of the motor axis direction tip P of the overhang portion 34ba is substantially the same as the motor radial direction position of the outer diameter side convex portion side end of the winding 35.

  The coil bobbin 34 includes two bobbin divided bodies 34A and 34B that are divided into two in the motor axial direction and are symmetrical to each other. The central portion 34a is formed in a cylindrical shape by combining two bobbin divided bodies 34A and 34B. One outer diameter side convex portion 34b and one inner diameter side convex portion 34c are provided on each of the bobbin divided bodies 34A and 34B.

  By dividing the coil bobbin 34 into the two bobbin divided bodies 34A and 34B in this way, as shown in FIG. 5, a plurality of individual coils 34 may be arranged side by side without opening a wide gap in the circumferential direction. The coil bobbin 34 can be attached so as to surround the outer periphery of the tooth portion 30b of the stator core 30. Specifically, the tooth portions 30b of the stator core 30 are sandwiched between the two bobbin divided bodies 34A and 34B from both sides in the motor axial direction, and the tooth portions 30b are disposed in the through holes 36 (FIG. 6) of the center portion 34a. Thereafter, the two bobbin divided bodies 34A and 34B are fixed to each other by fixing means (not shown) such as screws.

  After the coil bobbin 34 is attached to the tooth portion 30b of the stator core 30 as described above, the winding 35 is wound around the central portion 34a of the coil bobbin 34 as shown in FIGS. As described above, the motor radial direction position of the motor axis direction tip P of the overhang portion 34ba is the same as the motor radial direction position of the outer diameter side convex portion side end of the winding 35 or on the outer diameter side. When the winding 35 is wound, the overhang portion 34ba does not get in the way.

Next, the oil-cooled cooling device R will be described with reference to FIG.
The oil-cooled cooling device R serves as both cooling of the motor 1 and the speed reducer 2 and lubrication of the bearings 11, 12, 14 a and 14 b that support the speed reducer 2 and the rotating shaft 6. The oil cooling type cooling device R includes a pump 50 provided at the boundary between the reduction gear housing 7 and the motor housing 8, an oil sump 51 provided at the bottom of the reduction gear housing 7, and each part of the motor 1 and the reduction gear 2. It is comprised with the oil paths 52-60 provided in this.

  The pump 50 is, for example, a cycloid pump, and sucks the cooling oil of the oil reservoir 51 through the suction oil passage 52 and sends it out to the delivery oil passage 53. The delivery oil passage 53 is provided in the motor housing 8 and extends upward. The upper end of the delivery oil passage 53 communicates with the outboard side end of the axial oil passage 54 that extends in the motor housing 8 along the axial direction. The inboard side end of the axial oil passage 54 communicates with the upper end of a communication oil passage 55 provided in the motor cover 8 a of the motor housing 8. The lower end of the communication oil passage 55 extends to the position of the motor shaft center, and the lower end thereof communicates with the motor shaft oil supply passage 56. The motor shaft oil supply path 56 extends from the inboard side to the outboard side along the axis of the rotating shaft 6. The lower end of the communication oil passage 55 communicates with the inboard side of the motor shaft center oil supply passage 56.

  The motor shaft center oil supply passage 56 communicates with the speed reducer shaft center oil supply passage 57 in the reducer input shaft 3 at the outboard side end, and also communicates with the discharge oil passage 60 at the axial intermediate portion thereof.

  The reduction gear shaft center oil supply passage 57 will be described. The reducer shaft center oil supply passage 57 is provided in the reducer input shaft 3 along the shaft center, and extends from the inboard side to the outboard side. A speed reducer supply oil path 58 extends into the speed reducer housing 7 from the axial position where the eccentric portions 15 and 16 are provided in the speed reducer axial center oil supply path 57. Further, the inside of the reduction gear housing 7 and the oil reservoir 51 are communicated with each other through a drain oil passage 59.

  As shown in FIG. 2, which is a partially enlarged view of FIG. 1, the discharge oil passage 60 includes the following radial holes 61, gaps 62, oil grooves 63, and oil holes 64. The radial hole 61 is provided in the motor radial direction across the rotating shaft 6 and the flange portion 13a of the fixed body 13, the inner diameter end communicates with the motor shaft center oil supply passage 56 (FIG. 1), and the outer diameter end is a gap. 62 is open. The gap 62 is a gap portion formed between the cylindrical portion 13b of the fixed body 13 and the inner peripheral surface of the rotor core 10a. The oil groove 63 is provided along the inner surface of the flange 13c of the fixed body 13 that is in contact with the end surface of the rotor core 10a, and the inner diameter end in the motor radial direction communicates with the gap 62. The oil hole 64 extends obliquely from the outer diameter end of the oil groove 63 in the motor radial direction toward the outer side in the motor axial direction and the outer diameter side in the motor radial direction, and the tip opens into the internal space S of the motor housing 8. .

  In FIG. 1, an oil drain groove 65 is provided at the bottom of the motor housing 8 which is the lower end of the internal space S. The oil drain groove 65 communicates with the oil reservoir 51.

  The cooling oil fed from the pump 50 flows through the delivery oil passage 53, the axial oil passage 54, and the communication oil passage 55 in order, and then flows to the motor shaft oil supply passage 56. A part of the cooling oil flowing through the motor shaft oil supply passage 56 flows into the reduction gear shaft oil supply passage 57, and the rest flows into the discharge oil passage 60.

  The cooling oil that has flowed into the reduction gear shaft center oil supply passage 57 is supplied to the inside of the reduction gear housing 7 through the reduction gear supply oil passage 58 by the pressure of the pump 50 and the centrifugal force accompanying the rotation of the reduction gear input shaft 3. The Each part in the speed reducer 2 is lubricated and cooled by this cooling oil. The cooling oil used for lubrication and cooling moves downward due to gravity and is returned to the oil sump 51 via the discharge oil passage 59.

  As shown in FIG. 2, the cooling oil that has flowed into the discharge oil passage 60 passes through the radial hole 61, the gap 62, the oil groove 63, and the oil hole 64 in this order and is discharged into the internal space S of the motor housing 8. . When the cooling oil passes through the gap 62 and the oil groove 63 in contact with the rotor core 10a, the rotor core 10a is cooled.

  The cooling oil discharged from the oil hole 64 diffuses the inner space S of the motor housing 8 to the outer side in the motor axial direction and the outer diameter side in the motor radial direction according to the inclination of the oil hole 64. The diffused cooling oil hits the overhang portion 34ba of the coil bobbin 34. The cooling oil that has hit the overhanging portion 34ba of the coil bobbin 34 is repelled by the repellent surface 37, hits the winding 35 of the individual coil 33, and cools the individual coil 33 efficiently.

  The position and angle of the oil hole 64 are determined so that the cooling oil discharged from the oil hole 64 hits the overhanging portion 34ba of the coil bobbin 34 when the motor 1 rotates at the rated rotation speed. Further, the inclination angle θ1 (FIG. 6) of the repellent surface 37 is determined so that the cooling oil repelled by the repellent surface 37 is guided to the winding 35 of the individual coil 33. Thus, the output of the motor 1 can be improved by efficiently cooling the individual coil 33 with the cooling oil.

  The oil used for cooling the motor 1 by the motor housing 8 is collected in the drain oil groove 65 at the bottom of the motor housing 8, and returned to the oil reservoir 51 from the oil drain groove 65.

  8 to 11 show different embodiments of the present invention. This motor drive device differs in the shape of the coil bobbin 34 of the individual coil 33 compared with the previous embodiment shown in FIGS. That is, as shown in FIG. 10, the repellent surface 37 ′ formed on the inner diameter surface of the protruding portion 34 ba of the outer diameter side convex portion 34 b of the coil bobbin 34 goes toward the tip side, that is, as it moves away from the winding 35. It inclines so that it may be located in the outer diameter side of a motor radial direction. The outer diameter surface of the overhang portion 34ba is along the motor shaft direction. That is, the overhang portion 34ba becomes thinner as it goes to the tip side in the motor shaft direction.

Further, as shown in FIG. 9 which is a partially enlarged view of FIG. 8, the oil hole 64 of the discharge oil passage 60 has an outer diameter in the motor radial direction as compared with the oil hole 64 (see FIG. 2) of the previous embodiment. The inclination angle to the outer diameter side with respect to the motor axial direction is gentle.
Except for the above points, the configuration is the same as that of the previous embodiment shown in FIGS. Parts having the same configuration are denoted by the same reference numerals in the drawings, and description thereof is omitted.

  By determining the position and the inclination angle of the oil hole 64 as described above, the cooling oil discharged from the oil hole 64 is sprayed toward the wall surface F of the motor housing 8. The cooling oil is repelled by the wall surface F and hits the repellent surface 37 ′ of the overhang portion 34 ba of the coil bobbin 34. Further, the repelling surface 37 ′ is repelled and hits the winding 35 of the individual coil 33 to cool the individual coil 33 efficiently.

  When the motor 1 rotates at the rated rotational speed, the position and angle of the oil hole 64 are such that the cooling oil discharged from the oil hole 64 hits the wall surface F of the motor housing 8 and then hits the overhanging portion 34ba of the coil bobbin 34. Is stipulated. Further, an inclination angle θ2 (FIG. 10) of the repellent surface 37 ′ with respect to the motor axis is determined so that the cooling oil repelled by the repellent surface 37 ′ is guided to the winding 35 of the individual coil 33. . Also in this case, the output of the motor 1 can be improved by efficiently cooling the individual coil 33 with the cooling oil.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Motor 6 ... Rotary shaft 8 ... Motor housing 9 ... Stator 10 ... Rotor 11, 12 ... Bearing 30 ... Stator core 30b ... Tooth part 31 ... Coil 33 ... Individual coil 34 ... Coil bobbin 34a ... Central part 34b ... Outer diameter side convex part 34c ... Convex part 34ba ... Overhang part 35 ... Winding 37, 37 '... Repellent surface 56 ... Motor shaft oil supply path 60 ... Discharge oil path R ... Oil cooling type cooling device S ... Internal space

Claims (7)

A stator including a stator core and a coil, a housing that covers and fixes the stator, a rotary shaft that is rotatably supported by the housing via a plurality of bearings, a rotor that is integrally fixed to the rotary shaft, and an oil The stator core has a plurality of teeth arranged radially around the axis of the rotating shaft, and the coil is composed of a plurality of individual coils provided on each of the teeth. The individual coil is a cooling structure for a motor including a coil bobbin that surrounds the outer periphery of the tooth portion, and a winding wound around the coil bobbin.
The oil cooling type cooling device includes a shaft center oil supply passage that supplies cooling oil through an axis of the rotating shaft, and a discharge that discharges the cooling oil to an internal space of the housing in communication with the shaft center oil supply passage. An oil passage,
Each of the coil bobbins has an overhang portion that protrudes at least in the motor axial direction from the winding diameter of the winding at the outer diameter end in the motor radial direction, and is discharged from the discharge oil passage to the overhang portion. A motor cooling structure, wherein a repellent surface is formed to repel the cooling oil diffused in the inner space of the housing toward the outer diameter side in the motor radial direction toward the winding.   2. The motor cooling structure according to claim 1, wherein the cooling oil from the discharge oil passage is inclined with respect to the motor axial direction on the outer diameter side in the motor radial direction and away from the rotor in the motor axial direction. A motor cooling structure in which the discharge oil passage is provided so that the discharge oil passage is provided.   3. The motor cooling structure according to claim 1, wherein the coil bobbin protrudes in a motor axial direction from a central portion around which the winding is wound and an outer diameter end of the central portion in the motor radial direction. An outer-diameter-side convex portion that insulates the housing and the winding; and an inner-diameter-side convex portion that projects in the motor axial direction from the inner diameter end of the central portion in the motor radial direction and insulates the rotor and the winding. The cooling structure of the motor, wherein a part of the outer-diameter-side convex portion is the protruding portion.   The motor cooling structure according to claim 3, wherein the outer-diameter-side convex portion protrudes more in the motor axial direction than the inner-diameter-side convex portion.   5. The motor cooling structure according to claim 1, wherein a cross-sectional shape obtained by cutting the repellent surface of the projecting portion along a plane passing through the axis of the rotation shaft is the winding. The cooling structure of the motor which inclines so that it may be located in the internal diameter side of a motor radial direction as it distances from a motor axial direction.   6. The motor cooling structure according to claim 5, wherein a motor radial direction position of a tip of the overhang portion in a motor axial direction is on the outer diameter side convex portion side of the winding wound around the central portion of the coil bobbin. The cooling structure of the motor which is the same as the end of the motor in the radial direction or the outer diameter side.   5. The motor cooling structure according to claim 1, wherein a cross-sectional shape obtained by cutting the repellent surface of the projecting portion along a plane passing through the axis of the rotation shaft is the winding. The cooling structure of the motor which inclines so that it may be located in the outer-diameter side of a motor radial direction as it distances from a motor axial direction.

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