unit

Abstract

To suppress the increase in the number of parts. [Solution] The unit has a duct section which includes a gear, an inlet into which airflow generated by the rotation of the gear is introduced, and a supply section which supplies the airflow introduced from the inlet.

Description

Technical Field

[0001] The present invention relates to a unit.

Background Art

[0002] Patent Document 1 discloses a configuration in which air is blown into a gear box using a blower (air blowing unit).

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Providing a blower (air blowing unit) increases the number of parts. This leads to an increase in the overall size of the unit and an increase in cost. Therefore, it is required to suppress an increase in the number of parts.

Means for Solving the Problems

[0005] A unit according to an aspect of the present invention includes a gear, a duct unit having an inlet through which an air flow generated by the rotation of the gear is introduced, and a supply unit that supplies the air flow introduced from the inlet.

Effects of the Invention

[0006] According to an aspect of the present invention, an increase in the number of parts can be suppressed.

Brief Description of the Drawings

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a unit. [Figure 2]Figure 2 is a diagram illustrating the unit. [Figure 3] Figure 3 is a diagram illustrating the power transmission mechanism. [Figure 4] Figure 4 illustrates the behavior of air around the power transmission mechanism. [Figure 5] Figure 5 is a diagram illustrating the duct section. [Figure 6] Figure 6 is a diagram illustrating the first duct. [Figure 7] Figure 7 is a diagram illustrating the first duct. [Figure 8] Figure 8 is a diagram illustrating the first duct. [Figure 9] Figure 9 is a diagram illustrating the first duct. [Figure 10] Figure 10 is a diagram illustrating the first duct. [Figure 11] Figure 11 is a diagram illustrating the second duct. [Figure 12] Figure 12 is a diagram illustrating the second duct. [Figure 13] Figure 13 is a diagram illustrating the second duct. [Figure 14] Figure 14 is a diagram illustrating the third duct. [Figure 15] Figure 15 is a diagram illustrating the third duct. [Figure 16] Figure 16 is a diagram illustrating the third duct. [Figure 17] Figure 17 is a diagram illustrating the third duct. [Figure 18] Figure 18 is a diagram illustrating the unit related to Modification Example 1. [Figure 19] Figure 19 is a diagram illustrating a unit relating to Modification Example 1. [Figure 20] Figure 20 is a diagram illustrating the unit related to Modification Example 2. [Figure 21] Figure 21 is a diagram illustrating the unit related to Modification Example 2. [Figure 22] Figure 22 is a diagram illustrating the unit related to Modification Example 3.

Best Mode for Carrying Out the Invention

[0008] First, the definitions of the terms used in this specification will be explained. A "unit" is also called a "motor unit", a "power transmission device", etc. A motor unit is a unit having at least a motor. A power transmission device is a device having at least a power transmission mechanism, and the power transmission mechanism is, for example, a gear mechanism and / or a differential gear mechanism, etc. A unit which is a device having a motor and a power transmission mechanism belongs to both the concepts of a motor unit and a power transmission device.

[0009] A "housing" is what houses a motor, gears, and an inverter. The housing is composed of one or more cases.

[0010] A "motor" is a rotating electric machine having an electric motor function and / or a generator function.

[0011] When it is described that element B (component, part, etc.) is connected to element A (component, part, etc.), element B (component, part, etc.) is connected downstream of element A (component, part, etc.), or element B (component, part, etc.) is connected upstream of element A (component, part, etc.), it means that element A and element B are connected so as to be able to transmit power. The power input side is the upstream, and the power output side is the downstream. Also, element A and element B may be connected via other elements (clutch, other gear mechanisms, etc.).

[0012] "Overlap in a predetermined direction view" means that a plurality of elements are arranged in a predetermined direction, and is synonymous with the case of being described as "overlap in a predetermined direction". The "predetermined direction" is, for example, the axial direction, the radial direction, the gravitational direction, the vehicle traveling direction (vehicle forward direction, vehicle reverse direction), etc. When it is illustrated on the drawing that a plurality of elements (components, parts, etc.) are arranged in a predetermined direction, in the description of the specification, it may be regarded that there is a sentence explaining that they overlap in the predetermined direction view.

[0013] "Not overlapping in a given direction" and "offset in a given direction" mean that multiple elements are not aligned in a given direction, and are equivalent to writing "not overlapping in a given direction" and "offset in a given direction." "Given direction" can be, for example, the axial direction, radial direction, direction of gravity, or vehicle travel direction (vehicle forward direction, vehicle reverse direction). If a drawing shows that multiple elements (parts, sections, etc.) are not aligned in a predetermined direction, it may be assumed that the description in the specification includes a statement explaining that they do not overlap when viewed in that predetermined direction.

[0014] The statement "In a given direction of view, element A (part, etc.) is located between element B (part, etc.) and element C (part, etc.)" means that when observed from a given direction, element A can be observed to be located between element B and element C. The "given direction" is, for example, the axial direction, radial direction, direction of gravity, vehicle travel direction (vehicle forward direction, vehicle reverse direction), etc. For example, if elements B, A, and C are arranged in this order along the axial direction, then in a radial view, element A can be said to be located between elements B and C. If the drawing shows that element A is located between elements B and C in a given direction, then it can be assumed that there is a sentence in the specification explaining that element A is located between elements B and C in a given direction.

[0015] When two elements (parts, components, etc.) overlap in an axial view, the two elements are coaxial.

[0016] "Axial direction" refers to the axial direction of the rotation axis of the components that make up the unit. "Radial direction" refers to the direction perpendicular to the rotation axis of the components that make up the unit. Examples of components include motors, gear mechanisms, differential gear mechanisms, etc.

[0017] The following describes this embodiment. In this embodiment, a unit 1 mounted on a vehicle will be used as an example. Figure 1 is a schematic diagram showing the general configuration of Unit 1. Figure 2 is a diagram illustrating unit 1. Figure 2 is a schematic diagram of cross-section AA in Figure 1. In Figure 2, cross-hatching is applied to the mating surface of the motor case 11 with the gear case 12. Here, "vertical direction" in the drawings refers to the direction of the vertical line VL, relative to the state in which Unit 1 is mounted on the vehicle. Therefore, when it is written as "upper side," it means the "upper side" in the direction of the vertical line VL, and when it is written as "lower side," it means the "lower side" in the direction of the vertical line VL. Also, "front-rear direction" refers to the front-rear direction of the vehicle, relative to the state in which Unit 1 is mounted on the vehicle. Therefore, when it is written as "front side," it means the "front side" in the front-rear direction, and when it is written as "rear side," it means the "rear side" in the front-rear direction.

[0018] As shown in Figure 1, unit 1 has a housing HS that houses the motor 2 and the power transmission mechanism 3. The housing HS consists of a motor case 11 that houses the motor 2 and a gear case 12 that houses the power transmission mechanism 3.

[0019] In unit 1, the rotational driving force of motor 2 is transmitted to power transmission mechanism 3. Power transmission mechanism 3 includes an input shaft 4 that rotates integrally with motor 2, an intermediate shaft 5 that transmits the rotation of input shaft 4 to differential mechanism 6, and drive shafts 7 (7A, 7B) that output the rotation of differential mechanism 6 to the left and right drive wheels WH, WH.

[0020] The input shaft 4 has a shaft 40 that is mounted coaxially with the motor shaft 20 of the motor 2, and an input gear 41 formed on the outer circumference of the shaft 40. The shaft 40 is spline-fitted with the motor shaft 20 and rotates together with the motor shaft 20 around the rotation axis X1.

[0021] The intermediate shaft 5 has a shaft 50 that runs along a rotation axis X2 parallel to the rotation axis X1, and a gear portion 55 provided on the outer circumference of the shaft 50. The gear portion 55 rotates integrally with the shaft 50 around the rotation axis X2.

[0022] The gear section 55 consists of two gears of different diameters (a large-diameter gear 51 and a small-diameter gear 52). In the direction of the rotation axis X2, the large-diameter gear 51 is located closer to the motor 2 than the small-diameter gear 52. The large-diameter gear 51 of the intermediate shaft 5 meshes with the input gear 41 of the input shaft 4. The small-diameter gear 52 of the intermediate shaft 5 meshes with the final gear 61 of the differential mechanism 6.

[0023] For example, if the final gear 61 is a gear, then the gear section 55, which is another gear that meshes with the final gear 61, constitutes the first gear. Furthermore, the input gear 41, which is yet another gear that meshes with the gear section 55, constitutes the second gear. Furthermore, when the input gear 41 is considered a gear, the gear section 55, which is another gear that meshes with the input gear 41, constitutes the first gear. In addition, the final gear 61, which is yet another gear that meshes with the gear section 55, constitutes the second gear.

[0024] The final gear 61 is fixed to the outer circumference of the differential case 60 and rotates together with the differential case 60 around the rotation axis X3. The rotation axis X3 is parallel to the rotation axes X1 and X2. The differential case 60 is connected to the drive shafts 7 (7A, 7B) via bevel gears 62 and side gears 63. Therefore, the drive shafts 7 (7A, 7B) rotate together with the final gear 61 around the rotation axis X3.

[0025] In unit 1, the rotation axis X1 of the motor shaft 20 and input shaft 4, the rotation axis X2 of the intermediate shaft 5, and the rotation axis X3 of the drive shaft 7 are arranged in this order from front to rear in the front-to-back direction.

[0026] These rotating shafts X1 to X3 are oriented along the width of the vehicle. In the following, these rotating shafts X1 to X3 will be collectively referred to as rotating shaft X, as needed.

[0027] The motor case 11 has a support wall portion 111 surrounding the rotating shaft X1. The support wall portion 111 is oriented along the rotating shaft X1. The motor 2 is housed inside the support wall portion 111. A gear case 12 is connected to one end 111a of the support wall portion 111 by bolts (not shown).

[0028] The support wall 111 is provided with a wall portion 112 that extends inward between the motor 2 and the power transmission mechanism 3. The wall portion 112 is oriented perpendicular to the rotation axis X1.

[0029] The space formed inside the motor case 11 and the gear case 12 is divided into two by a wall 112. The space on the motor 2 side from the wall 112 (upper side in the figure) is the motor chamber Sa that houses the motor 2. The space on the power transmission mechanism 3 side from the wall 112 (lower side in the figure) is the gear chamber Sb that houses the power transmission mechanism 3.

[0030] In the wall portion 112, a cylindrical wall portion 113 is provided in the region where the rotation axis X1 intersects, surrounding the rotation axis X1. A bearing Bm is provided on the inner circumference of the cylindrical wall portion 113 on the motor chamber Sa side. The motor shaft 20 is supported by the cylindrical wall portion 113 via the bearing Bm. A bearing B4 is provided on the inner circumference of the cylindrical wall portion 113 on the gear chamber Sb side. The shaft 40 of the input shaft 4 is supported by the cylindrical wall portion 113 via the bearing B4.

[0031] On the side of the wall portion 112 facing the power transmission mechanism 3 (lower side in the figure), a cylindrical wall portion 114 is provided behind the rotating shaft X1. The cylindrical wall portion 114 is cylindrical in shape and surrounds the rotating shaft X2. A bearing B5 is provided on the inner circumference of the cylindrical wall portion 114. The bearing B5 supports the shaft 50 of the intermediate shaft 5.

[0032] The motor case 11 has a bulging wall portion 15 that extends rearward from the support wall portion 111 on the rear side (left side in the figure) of the vehicle. The bulging wall portion 15 is formed by enlarging a part of the motor case 11 in order to accommodate the differential mechanism 6, which is located on the rear side of the vehicle as viewed from the motor 2.

[0033] The bulging wall portion 15 has a wall portion 151 that protrudes from the outer circumference of the support wall portion 111 toward the rear side of the vehicle, and a wall portion 152 provided at the rear end of the wall portion 151. The wall portion 151 is provided in a direction perpendicular to the rotation axis X3.

[0034] In the wall portion 151, a cylindrical differential case support portion 151a is provided in the region where the rotation axis X3 intersects. The support cylinder 601 of the differential case 60 penetrates the differential case support portion 151a in the direction of the rotation axis X3.

[0035] A bearing B6 is supported on the inner circumference of the differential case support portion 151a. The support cylinder 601 of the differential case 60 is supported by the differential case support portion 151a via the bearing B6.

[0036] The wall portion 152 is oriented along the rotation axis X3. One end 152a of the wall portion 152 in the direction of the rotation axis X3 is flush with one end 111a of the support wall portion 111. The gear case 12 is connected to one end 152a of the wall portion 152 by bolts (not shown).

[0037] The gear case 12 has a bottom wall portion 120 provided in a direction perpendicular to the rotation axes X1 to X3, and a peripheral wall portion 121 that surrounds the outer edge of the bottom wall portion 120 over its entire circumference. The front end surface 121a of the peripheral wall portion 121 is joined to one end 111a of the support wall portion 111 in the front region in the vehicle's longitudinal direction (the region on the right in Figure 1), and to one end 152a of the wall portion 152 of the bulging wall portion 15 in the rear region (the region on the left in Figure 1).

[0038] In the bottom wall portion 120, a bearing B4 is provided in the region where the rotating shafts X1 intersect. The bearing B4 supports the shaft 40 of the input shaft 4. As a result, the input shaft 4 is supported at both ends in the direction of the rotation axis X1 by the motor case 11 and the gear case 12, and is provided to be rotatable around the rotation axis X1.

[0039] In the bottom wall portion 120, a bearing B5 is provided in the region where the rotating shafts X2 intersect. The bearing B5 supports the shaft 50 of the intermediate shaft 5. As a result, the intermediate shaft 5 is supported at both ends in the direction of the rotation axis X2 by the motor case 11 side and the gear case 12 side, and is provided to be rotatable around the rotation axis X2.

[0040] In the bottom wall portion 120, the support cylinder 602 of the differential case 60 penetrates in the direction of the rotation axis X3 in the region where the rotation axis X3 intersects. The bottom wall portion 120 is provided with a cylindrical differential case support portion 122 that surrounds the support cylinder 602. A bearing B6 is supported on the inner circumference of the differential case support portion 122. The support cylinder 602 of the differential case 60 is supported by the differential case support portion 122 via the bearing B6. As a result, the differential case 60 is supported at both ends in the direction of the rotation axis X3 by the motor case 11 side and the gear case 12 side, and is provided to be rotatable around the rotation axis X3.

[0041] Drive shafts 7A and 7B are inserted through the inner circumferences of the support cylinders 601 and 602 of the differential case 60. The rotation of the differential case 60 is transmitted to the drive shafts 7A and 7B via the bevel gear 62 and the side gear 63. Therefore, in conjunction with the rotation of the differential case 60, the drive shafts 7A and 7B also rotate around the rotation axis X3.

[0042] Motor 2 includes a motor shaft 20, a cylindrical rotor 21 fitted onto the motor shaft 20, and a stator 22 that surrounds the outer circumference of the rotor 21 at intervals. The stator 22 is inserted into the inner circumference of the support wall 111. Bearing Bm is externally fitted to the motor shaft 20. Although not shown in the diagram, bearing Bm is provided at both ends of the motor shaft 20 in the direction of the rotation axis X1. The motor shaft 20 is rotatably supported by the motor case 11 via bearing Bm.

[0043] The stator 22 of motor 2 is supplied with power from a battery (not shown) via an inverter (not shown). When power is supplied to the stator 22, a magnetic field is generated around the stator 22. This causes the rotor 21 and the motor shaft 20 to rotate around the rotation axis X1, driving the motor 2. The rotation of the motor shaft 20 is transmitted in the order of the input shaft 4, intermediate shaft 5, and differential mechanism 6 of the power transmission mechanism 3, and is finally output from the drive shafts 7A and 7B.

[0044] As shown in Figure 2, when the vehicle is moving forward, the input shaft 4 rotates clockwise (CW) when viewed from the direction of the rotation axis X1. The large-diameter gear 51 of the intermediate shaft 5, which meshes with the input gear 41 of the input shaft 4, rotates counterclockwise (CCW) when viewed from the direction of the rotation axis X2. The small-diameter gear 52, which rotates integrally with the large-diameter gear 51, also rotates counterclockwise (CCW) when viewed from the direction of the rotation axis X2. The final gear 61 of the differential mechanism 6, which meshes with the small-diameter gear 52, rotates clockwise (CW) when viewed from the direction of the rotation axis X3.

[0045] Here, the input gear 41 of the input shaft 4 has teeth 411 and tooth grooves 412 arranged alternately around the entire circumference in the circumferential direction around the rotation axis X1. The large diameter gear 51 of the intermediate shaft 5 has teeth 511 and tooth grooves 512 arranged alternately around the entire circumference in the circumferential direction around the rotation axis X2. The small diameter gear 52 also has teeth 521 and tooth grooves 522 arranged alternately around the entire circumference in the circumferential direction around the rotation axis X2. The final gear 61 of the differential mechanism 6 has teeth 611 and tooth grooves 612 arranged alternately around the entire circumference in the circumferential direction around the rotation axis X3.

[0046] Each gear in the power transmission mechanism 3 (input gear 41, large diameter gear 51, small diameter gear 52, final gear 61) stirs up air in the gear chamber Sb as its teeth (teeth 411, teeth 511, teeth 521, teeth 611) rotate. At this time, air resistance acts on each gear. Therefore, the air resistance acting on each gear of the power transmission mechanism 3 results in wind loss, and the rotational driving force output from the drive shaft 7 is attenuated compared to the rotational driving force input from the motor 2.

[0047] Here, the input gear 41 of the input shaft 4, the large-diameter gear 51 and small-diameter gear 52 of the intermediate shaft 5, and the final gear 61 of the differential mechanism 6 are all helical gears (see Figure 3). Through diligent research, the inventors of this invention discovered that in a helical gear, the air stirred up by rotation flows in a directional manner. Therefore, in the unit 1 according to this embodiment, a duct section 8 through which air flows is provided so that the airflow generated by the rotation of the helical gear can be used to reduce windage losses.

[0048] As shown in Figure 1, the duct section 8 consists of three ducts (first duct 81, second duct 82, and third duct 83). The first duct 81 to the third duct 83 are cylindrical members with one end and the other end open in the longitudinal direction. The first duct 81 to the third duct 83 are made of resin or the same material as the constituent material of the housing HS. The first duct 81 to the third duct 83 are each fixed to the walls 112 and 151 (see Figure 2) of the motor case 11 via bolts B (see Figure 2).

[0049] As will be explained in more detail later, as shown in Figure 2, the first duct 81 takes in the airflow generated by the rotation of the final gear 61 and blows it onto the input gear 41. The second duct 82 takes in the airflow generated by the rotation of the input gear 41 and blows it onto the final gear 61. The third duct 83 takes in the airflow generated by the rotation of the large-diameter gear 51 and blows it onto the same large-diameter gear 51.

[0050] Figure 3 is a diagram illustrating the power transmission mechanism 3. In Figure 3, the input shaft 4, intermediate shaft 5, and differential mechanism 6 are positioned spaced apart in the front-rear direction to make the positional relationship between the input shaft 4, intermediate shaft 5, and differential mechanism 6 shown in Figure 1 easier to understand. In addition, different types of hatching are used to make the positions of the teeth 411, 511, 521, and 611 of the gears (input gear 41, gear section 55, final gear 61) of the input shaft 4, intermediate shaft 5, and differential mechanism 6 easier to understand. Figure 4 illustrates the behavior of air Ar around the power transmission mechanism 3. As an example, Figure 4 shows the behavior of air Ar generated around the meshing portion of the final gear 61 and the small-diameter gear 52. In Figure 4, the air velocity is shown in stages using different hatching patterns. The faster the air velocity, the narrower the spacing of the hatching pitch.

[0051] The following describes the airflow generated by each gear (input gear 41, gear section 55, final gear 61).

[0052] [Input Gear 41] As shown in Figure 3, the input gear 41 is a helical gear (a left-handed helical gear). Viewed from the radial direction of the rotation axis X1, the input gear 41 has teeth 411 and tooth grooves 412 on its outer circumference that are inclined with respect to the rotation axis X1. The teeth 411 and tooth grooves 412 extend from one end 411a to the other end 411b of the input gear 41 along a straight line Lm1 that is inclined with respect to the rotation axis X1.

[0053] One end 411a and the other end 411b of the tooth portion 411 are offset in the rotational direction of the input gear 41 (left-right direction in the figure). The tooth portion 411 and the tooth groove portion 412 are positioned such that the end 411a is located further forward of the vehicle than the other end 411b in the direction of the rotation axis X1.

[0054] In the case of Figure 3, when the vehicle equipped with Unit 1 is moving forward, the input gear 41 rotates in one direction (clockwise CW) around the rotation axis X1. When the input gear 41 rotates clockwise (CW) around the rotation axis X1, a flow of air Ar is generated between adjacent teeth 411, 411 in the circumferential direction (tooth groove 412), along the teeth 411.

[0055] The inventors of this application have found the following points through diligent study. (a) The direction in which air Ar flows between the teeth 411, 411 is along the straight line Lm1, from one end 411a to the other end 411b of the teeth 411 (see the thick arrow in Figure 3), and at the other end 411b of the input gear 41, air is blown out from the tooth groove portion 412. (b) The amount of air Ar blown out from the tooth groove portion 412 increases as the rotational speed of the input gear 41 increases. (c) Around the input gear 41, the wind speed is stronger in the region R that is offset towards the motor case 11, rather than the region that overlaps with the input gear 41 when viewed from the radial direction of the rotation axis X1 (for example, directly above the input gear 41), and is on the outer diameter side of the input gear 41 when viewed from the direction of the rotation axis X1.

[0056] Here, when the input gear 41 is viewed from the radial direction of the rotation axis X1, the teeth 411 of the input gear 41 have one end 411a (gear case 12 side) that is the side where meshing with the teeth 511 of the large diameter gear 51 begins, relative to the intermediate line C1.

[0057] Furthermore, the teeth 411 of the input gear 41 have their engagement with the teeth 511 of the large-diameter gear 51 ending on the other end 411b side (motor case 11 side) relative to the intermediate line C1. The intermediate line C1 is a straight line that passes through the center of the input gear 41 in the direction of the rotation axis X1 and is perpendicular to the rotation axis X1. In the following explanation, the region on one end 411a of the tooth portion 411, as viewed from the median line C1, will be simply referred to as "end 411a side," and the region on the other end 411b side will be simply referred to as "other end 411b side."

[0058] In other words, while the input gear 41 is rotating around the rotation axis X1, an airflow Ar is generated in the input gear 41, moving from the side where meshing with the large-diameter gear 51 begins (one end 411a) to the side where meshing ends (the other end 411b).

[0059] The intermediate shaft 5 is equipped with a large-diameter gear 51 and a small-diameter gear 52. The large-diameter gear 51 and the small-diameter gear 52 are helical gears (right-handed helical gears). [Large diameter gear 51] Viewed from the radial direction of the rotation axis X2, the teeth 511 and tooth grooves 512 on the outer circumference of the large-diameter gear 51 are inclined with respect to the rotation axis X2. The teeth 511 and tooth grooves 512 extend from one end 511a to the other end 511b of the large-diameter gear 51 along a straight line Lm2 that is inclined with respect to the rotation axis X2.

[0060] One end 511a and the other end 511b of the tooth portion 511 are offset in the rotational direction (left-right direction in the figure) of the large-diameter gear 51. The tooth portion 511 and the tooth groove portion 512 are positioned such that the end 511a is located further rearward on the vehicle than the other end 511b in the direction of the rotation axis X2.

[0061] In the case of Figure 3, when the vehicle equipped with unit 1 is moving forward, the large-diameter gear 51 rotates in the opposite direction (counterclockwise, CCW) around the rotation axis X2. When the large-diameter gear 51 rotates counterclockwise (CCW) around the rotation axis X2, an airflow Ar is generated between adjacent teeth 511, 511 in the circumferential direction (tooth groove 512), along the teeth 511.

[0062] The inventors of this application have found the following points through diligent study. (a) The direction in which air Ar flows between the teeth 511, 511 is along the straight line Lm2, from one end 511a to the other end 511b of the teeth 511 (direction of the thick arrow in Figure 3), and at the other end 511b of the large diameter gear 51, air Ar is blown out from the tooth groove portion 512. (b) The amount of air Ar blown out from the tooth groove portion 512 increases as the rotational speed of the large-diameter gear 51 increases. (c) Around the large-diameter gear 51, the wind speed is stronger in the region R that is offset toward the motor case 11 side (end of meshing side) than the region that overlaps with the large-diameter gear 51 when viewed from the radial direction of the rotation axis X2 (for example, directly above the large-diameter gear 51), and is on the outer diameter side of the large-diameter gear 51 when viewed from the direction of the rotation axis X2.

[0063] Here, when the large-diameter gear 51 is viewed from the radial direction of the rotation axis X2, the teeth 511 of the large-diameter gear 51 are such that one end 511a (towards the gear case 12) is the side where meshing with the teeth 411 of the input gear 41 begins, relative to the intermediate line C2.

[0064] Furthermore, the teeth 511 of the large-diameter gear 51 have their engagement with the teeth 411 of the input gear 41 ending on the other end 511b side (motor case 11 side) relative to the intermediate line C2. The intermediate line C2 is a straight line that passes through the center of the large-diameter gear 51 in the direction of the rotation axis X2 and is perpendicular to the rotation axis X2. In the following explanation, the region on one end 511a of the tooth portion 511, as viewed from the median line C2, will be simply referred to as "end 511a side," and the region on the other end 511b side will be simply referred to as "other end 511b side."

[0065] In other words, while the large-diameter gear 51 is rotating around the rotation axis X2, an airflow Ar is generated from the side where meshing with the input gear 41 begins (one end 511a) to the side where meshing ends (the other end 511b).

[0066] [Small diameter gear 52] Viewed from the radial direction of the rotation axis X2, the teeth 521 and tooth grooves 522 on the outer circumference of the small-diameter gear 52 are inclined with respect to the rotation axis X2. The teeth 521 and tooth grooves 522 extend along a straight line Lm2' from one end 521a to the other end 521b of the small-diameter gear 52.

[0067] One end 521a and the other end 521b of the tooth portion 521 are offset in the rotational direction (left-right direction in the figure) of the small diameter gear 52. The tooth portion 521 and the tooth groove portion 522 are positioned such that the end 521a is located further rearward on the vehicle than the other end 521b in the direction of the rotation axis X2.

[0068] In the case of Figure 3, when the vehicle equipped with unit 1 is moving forward, the small-diameter gear 52 rotates together with the large-diameter gear 51 in the opposite direction (counterclockwise, CCW) around the rotation axis X2. When the small-diameter gear 52 rotates counterclockwise (CCW) around the rotation axis X2, an airflow Ar is generated between adjacent teeth 521, 521 in the circumferential direction (tooth groove 522), along the teeth 521.

[0069] The inventors of this application have found the following points through diligent study. (a) The direction in which air Ar flows between the teeth 521, 521 is along the straight line Lm2', from one end 521a to the other end 521b of the teeth 521 (direction of the thick arrow in Figure 3), and at the other end 521b of the small diameter gear 52, air Ar is blown out from the tooth groove portion 522. (b) The amount of air Ar blown out from the tooth groove portion 522 increases as the rotational speed of the small diameter gear 52 increases. (c) Around the small diameter gear 52, the wind speed is stronger in the region R that is offset towards the motor case 11, rather than the region that overlaps with the small diameter gear 52 when viewed from the radial direction of the rotation axis X2 (for example, directly above the small diameter gear 52), and is on the outer diameter side of the small diameter gear 52 when viewed from the direction of the rotation axis X2.

[0070] Here, when viewing the small-diameter gear 52 from the radial direction of the rotation axis X2, the teeth 521 of the small-diameter gear 52 are such that one end 521a (gear case 12 side) is the side where meshing with the teeth 611 of the final gear 61 begins, relative to the intermediate line C2'.

[0071] Furthermore, the teeth 611 of the final gear 61 have their engagement end on the other end 521b side (motor case 11 side) relative to the intermediate line C2'. The intermediate line C2' is a straight line that passes through the center of the small diameter gear 52 in the direction of the rotation axis X2 and is perpendicular to the rotation axis X2. In the following explanation, the region on one end 521a of the tooth portion 521, as viewed from the median line C2', will be simply referred to as "end 521a side," and the region on the other end 521b side will be simply referred to as "other end 521b side."

[0072] In other words, while the small-diameter gear 52 is rotating around the rotation axis X2, an airflow Ar is generated in the small-diameter gear 52, moving from the side where meshing with the final gear 61 begins (one end 521a) to the side where meshing ends (the other end 521b).

[0073] [Final Gear 61] The final gear 61 of the differential mechanism 6 is a helical gear (a left-handed helical gear). Viewed from the radial direction of the rotation axis X3, the teeth 611 and tooth grooves 612 on the outer circumference of the final gear 61 are inclined with respect to the rotation axis X3. The teeth 611 and tooth grooves 612 extend from one end 611a to the other end 611b of the final gear 61 along a straight line Lm3 that is inclined with respect to the rotation axis X3.

[0074] One end 611a and the other end 611b of the tooth portion 611 are offset in the rotational direction of the input gear 41 (left-right direction in the figure). The tooth portion 611 and the tooth groove portion 612 are positioned so that the end 611a is located further forward of the vehicle than the other end 611b in the direction of the rotation axis X1.

[0075] In the case of Figure 3, when the vehicle equipped with Unit 1 is moving forward, the final gear 61 rotates in one direction (clockwise CW) around the rotation axis X3. When the final gear 61 rotates clockwise (CW) around the rotation axis X3, an airflow Ar is generated between adjacent teeth 611, 611 in the circumferential direction (tooth groove 612), along the teeth 611.

[0076] The inventors of this application have found the following points through diligent study. (a) The direction in which air Ar flows between the teeth 611, 611 is along the straight line Lm3, from one end 611a to the other end 611b of the teeth 611 (see the thick arrow in Figure 3), and at the other end 611b of the final gear 61, air is blown out from the tooth groove 612. (b) The amount of air Ar blown out from the tooth groove portion 612 increases as the rotational speed of the final gear 61 increases. (c) Around the final gear 61, the wind speed is stronger in the region R that is offset towards the motor case 11, rather than the region that overlaps with the final gear 61 when viewed from the radial direction of the rotation axis X3 (for example, directly above the final gear 61), and is on the outer diameter side of the final gear 61 when viewed from the direction of the rotation axis X3.

[0077] Here, when viewing the final gear 61 from the radial direction of the rotation axis X3, the teeth 611 of the final gear 61 have one end 611a (gear case 12 side) that engages with the teeth 521 of the small diameter gear 52 at the end relative to the intermediate line C3.

[0078] Furthermore, the teeth 611 of the final gear 61 have their engagement with the teeth 521 of the small-diameter gear 52 ending on the other end 611b side (motor case 11 side) relative to the intermediate line C3. The intermediate line C3 is a straight line that passes through the center of the final gear 61 in the direction of the rotation axis X3 and is perpendicular to the rotation axis X3. In the following explanation, the region on one end 611a of the tooth portion 611, as viewed from the median line C3, will also be simply referred to as "the 611a side of the tooth portion 611," and the region on the other end 611b will also be simply referred to as "the 611b side of the tooth portion 611."

[0079] In other words, while the final gear 61 is rotating around the rotation axis X1, an airflow Ar is generated in the final gear 61, moving from the side where the meshing with the small diameter gear 52 begins (one end 611a) to the side where the meshing ends (the other end 611b).

[0080] Thus, the inventors of this application have found that when a helical gear rotates, the air inside the housing HS, which is stirred up by the rotation of the helical gear, moves in a directional manner toward the end of the meshing between the gears. Therefore, in this embodiment, an inlet for the duct section 8 (see, for example, the inlet 810a of the first duct 81 in Figure 6) is provided in the region R (see Figure 4) on the outer diameter side of each gear (input gear 41, large diameter gear 51, final gear 61) when viewed from the direction of the rotation axis X, at the end of the meshing of each gear (input gear 41, large diameter gear 51, final gear 61), so that the air Ar that is stirred up by the rotation of each gear can be actively taken in.

[0081] The following describes an example of the arrangement of the duct section 8. Figure 5 is a diagram illustrating the duct section 8. Figure 5 corresponds to the positional relationship between the power transmission mechanism 3 and the duct section 8 shown in Figure 1. In Figure 5, the final gear 61 is partially omitted, and one end 82a of the second duct 82 is exposed. Figure 6 is a diagram illustrating the first duct 81. Figure 6 is a perspective view of the final gear 61 in Figure 2, taken from the direction of arrow AA. Figure 7 is a diagram illustrating the first duct 81. Figure 7 is a perspective view of the final gear 61 and the first duct 81 in Figure 6, seen from the front. Figure 8 is a diagram illustrating the first duct 81. Figure 8 is an enlarged view of area B in Figure 2. Figure 9 is a diagram illustrating the first duct 81. Figure 9 is a schematic diagram of the AA section in Figure 8. Figure 10 is a diagram illustrating the first duct 81. Figure 10 is a schematic diagram of the AA section in Figure 5.

[0082] (First duct) As shown in Figure 2, when viewed from above, the first duct 81 is a cylindrical member in which a first passage 811 and a second passage 812 are connected in series. As shown in Figure 5, the inside of the first duct 81 is a hollow section 810 that connects one end 81a and the other end 81b.

[0083] Viewed from above, the first duct 81 is positioned along a straight line Ln1 perpendicular to the rotation axis X. Straight line Ln1 is a straight line along the longitudinal direction of the vehicle and, viewed from above, overlaps with the large-diameter gear 51 and the input gear 41. Furthermore, viewed from above, straight line Ln1 is located closer to the motor case 11 (upper side in the figure) than the final gear 61.

[0084] One end 81a of the first duct 81 is provided to the side of the final gear 61, with its opening facing in the direction of the straight line Ln1. The other end 81b of the first duct 81 is provided above the input gear 41, with its opening facing in the direction of the straight line Ln1.

[0085] Viewed from above, the first duct 81 is provided in a straight line along the straight line Ln1. The first duct 81 is provided so as to cross the upper side of the large diameter gear 51 from the final gear 61 side (rear of the vehicle) to the input gear 41 side (front of the vehicle).

[0086] As shown in Figure 2, when viewed from the direction of the rotation axis X, the first duct 81 is located above the final gear 61 (differential mechanism 6), the large-diameter gear 51 (intermediate shaft 5), and the input gear 41 (input shaft 4), and is oriented along the longitudinal direction of the vehicle.

[0087] Viewed from the direction of the rotation axis X, the first passage 811 of the first duct 81 is formed in an arc shape along the outer circumference of the final gear 61. Viewed from the direction of the rotation axis X, the second passage 812 is formed in a straight line. The second passage 812 is inclined so that its vertical position becomes lower as it approaches the input gear 41 (vehicle front side).

[0088] As shown in Figure 6, one end 81a of the first duct 81 is located on the outer diameter side (upper side in the figure) of the teeth 611 of the final gear 61, and is located away from the other end 611b of the final gear 61 in the direction of the rotation axis X3 (left side in the figure).

[0089] As shown in Figure 8, when viewed from the direction of the rotation axis X, one end 81a of the first duct 81 is located on the rearward side of the rotation axis X3 and above the rotation axis X3. Viewed from the direction of the rotation axis X, one end 81a of the first duct 81 is a flat surface along the diameter line Lr3 passing through the rotation axis X3. The diameter line Lr3 is perpendicular to the virtual circle Im1 (outer circle) along the outer surface 611c of the final gear 61.

[0090] The opening (inlet 810a) that serves as the entrance to the hollow section 810 of the first duct 81 is oriented in a direction along the tangent line L61a that is tangent to the virtual circle Im1. Viewed from the direction of the rotation axis X3, the inlet 810a opens facing upstream of the rotation direction (clockwise CW) of the final gear 61 when the vehicle equipped with unit 1 is traveling forward. Here, the opening direction of the inlet 810a can be said to be opposite to the rotation direction (clockwise CW) of the final gear 61 when the vehicle equipped with unit 1 is traveling forward.

[0091] Here, when the final gear 61 rotates clockwise (CW) in Figure 8, as shown in Figure 9, an airflow Ar is generated along the tooth groove 612 of the outer circumference of the final gear 61, moving from one end 611a to the other end 611b of the tooth portion 611 (see arrow in the figure).

[0092] In this case, the direction of air movement is the direction of vector Fa, which is the result of combining vector Fx, which is in the direction along the tooth groove 612, and vector Fcw, which is in the direction along the rotational direction of the final gear 61. Therefore, when the vehicle equipped with unit 1 is moving forward, the rotation of the final gear 61 generates an airflow Ar (airflow AC1) in the direction of vector Fa in the aforementioned region R to the side of the final gear 61.

[0093] Here, the vector Fcw in the direction along the rotational direction of the final gear 61 is greater than the vector Fx in the direction along the tooth groove 612. Therefore, the airflow (airflow AC1) generated by the rotation of the final gear 61, when viewed from the direction of the rotation axis X3, is in the direction along the tangent line L61a, as shown in Figure 8. The airflow AC1 flowing along the tangent line L61a then moves across the diameter line Lr3 from bottom to top.

[0094] Therefore, by setting the opening direction of the inlet 810a to align with the tangent L61a of the virtual circle Im1, and oriented in the opposite direction to the clockwise direction CW of the final gear 61, the airflow AC1 can be efficiently drawn into the hollow section 810 of the first duct 81 from the inlet 810a (see the white arrow in Figure 9).

[0095] As shown in Figures 5 and 7, the airflow AC1 taken into the hollow section 810 from one end 81a of the first duct 81 is pushed by the airflow AC1 flowing in sequentially from the end 81a side, moves from the first passage 811 to the second passage 812, and is discharged from the other end 81b.

[0096] As shown in Figures 5 and 7, the other end 81b of the first duct 81 is located above the input gear 41. As shown in Figure 10, when viewed from the direction of the rotation axis X, the other end 81b of the first duct 81 is located on the rearward side of the vehicle relative to the rotation axis X1 and above the rotation axis X1.

[0097] Viewed from the direction of the rotation axis X, the other end 81b of the first duct 81 faces the input gear 41 from the direction of the tangent L41a of the virtual circle Im2 along the outer circumferential surface 411c of the input gear 41. The other end 81b of the first duct 81 is a flat surface along the straight line La. The straight line La intersects the tangent L41a at a predetermined angle θ1.

[0098] The opening (discharge port 810b) that serves as the outlet from the hollow section 810 of the first duct 81 is positioned to face downstream in the direction of rotation (clockwise direction CW) of the input gear 41 when the vehicle equipped with unit 1 is traveling forward. Here, the opening direction of the discharge port 810b can be said to be the same direction as the rotation direction (clockwise CW) of the input gear 41 when the vehicle equipped with unit 1 is traveling forward. Viewed from the tangential L41a direction, the discharge port 810b overlaps with the teeth 411 of the input gear 41.

[0099] Therefore, the airflow AC1 discharged from the outlet 810b is blown onto the teeth 411 of the input gear 41 from the tangential L41a direction. The direction of the airflow AC1 is aligned with the clockwise direction CW of the input gear 41. As a result, the clockwise rotation CW of the input gear 41 is assisted by the airflow AC1 discharged from the first duct 81. Thus, the effect of air resistance can be reduced, and windage losses generated when the input gear 41 rotates can be reduced.

[0100] Here, as shown in Figure 10, the other end 81b of the first duct 81 is a flat surface along a straight line La that is inclined by a predetermined angle θ1 with respect to the tangent L41a. The angle θ1 between the tangent L41a and the straight line La is acute. As a result, the discharge port 810b can be brought closer to the input gear 41 in the vertical direction than, for example, if the angle θ1 were a right angle or an obtuse angle. This allows the airflow AC1 to be blown onto the input gear 41 more effectively.

[0101] In this way, by utilizing the airflow AC1 generated by the rotation of the final gear 61, it becomes possible to eliminate the need for a separate blower or other device to generate airflow. This helps to suppress an increase in the number of parts.

[0102] (Second duct) As shown in Figure 5, when viewed from above, the second duct 82 is a cylindrical member in which the first passage 821, the third passage 823, and the second passage 822 are connected in series. The inside of the second duct 82 is a hollow section 820 that connects one end 82a and the other end 82b.

[0103] Viewed from above, the first passage 821 of the second duct 82 is located on the motor case 11 side (upper side in the figure) of the input gear 41 and is oriented along the straight line Ln2. The other end 82b of the second duct 82 is provided with an opening facing the direction of the straight line Ln2.

[0104] Viewed from above, the second passage 822 of the second duct 82 is positioned to overlap with the final gear 61 and the small-diameter gear 52, and is oriented along the straight line Ln3. One end 82a of the second duct 82 is provided with an opening facing in the direction of the straight line Ln3.

[0105] Here, lines Ln1, Ln2, and Ln3 are parallel to each other. These lines Ln1, Ln2, and Ln3 are perpendicular to the axes of rotation X1, X2, and X3. Line Ln2 is located on the motor case 11 side (upper side in the diagram) when viewed from line Ln1. Line Ln3 is located on the gear case 12 side (upper side in the diagram) when viewed from line Ln1.

[0106] Viewed from above, the first passage 821 and the second passage 822 are offset in the direction of the rotation axis X. The first passage 821 and the second passage 822 are connected to each other via the third passage 823. Viewed from above, the third passage 823 is inclined with respect to the straight line Ln1. The third passage 823 is provided so as to diagonally cross the region where the small-diameter gear 52 and the large-diameter gear 51 are located.

[0107] As shown in Figure 2, when viewed from the direction of the rotation axis X, the second duct 82 is located below the input gear 41 (input shaft 4), the large-diameter gear 51 and the small-diameter gear 52 (intermediate shaft 5), and the final gear 61 (differential mechanism 6), and is oriented along the longitudinal direction of the vehicle.

[0108] Viewed from the direction of the rotation axis X, the second passage 822 of the second duct 82 is formed in a straight line along the horizontal line HL. One end 82a of the second passage 822 is inserted into the area below the final gear 61 from the input gear 41 side (right side in the figure) of the final gear 61. The range from the second passage 822 to the first passage 821 is formed in an arc shape, with the vertical position increasing as it moves towards the input gear 41 (front of the vehicle).

[0109] In this embodiment, the outer diameter decreases in the order of final gear 61, large diameter gear 51, and input gear 41. Therefore, the other end 82b of the first passage 821 is formed in an arc shape in order to position the opening of the other end 82b closer to the input gear 41.

[0110] Figure 11 is a diagram illustrating the second duct 82. Figure 11 is an enlarged view of area C in Figure 2. Figure 12 is a diagram illustrating the second duct 82. Figure 12 is a schematic diagram of the AA section of Figure 11. Figure 13 is a diagram illustrating the second duct 82. Figure 13 is a schematic diagram of the BB cross section in Figure 5.

[0111] As shown in Figure 12, the region on the other end 82b side of the first passage 821 is provided in a direction perpendicular to the rotation axis X1. As shown in Figure 11, when viewed from the direction of the rotation axis X1, the other end 82b of the second duct 82 is located on the vehicle front side of the rotation axis X1 and below the rotation axis X1. When viewed from the direction of the rotation axis X1, the first passage 821 of the second duct 82 is located on the outer diameter side of the teeth 411 of the input gear 41. The first passage 821 curves toward the outer circumferential surface 411c of the input gear 41 as it moves toward the front side of the vehicle (right side in the figure).

[0112] Viewed from the direction of the rotation axis X1, the other end 82b of the second duct 82 is a flat surface along the diameter line Lr1 passing through the rotation axis X1. The diameter line Lr1 is perpendicular to the virtual circle Im2 along the outer surface 411c of the input gear 41.

[0113] The opening (inlet 820b) that serves as the entrance to the hollow section 820 of the second duct 82 is oriented in a direction along the tangent line L41b that is tangent to the virtual circle Im2. Viewed from the direction of the rotation axis X1, the inlet 820b opens facing the upstream side of the rotation direction (clockwise CW) of the input gear 41 when the vehicle equipped with unit 1 is traveling forward. Here, the opening direction of the inlet 820b can be said to be opposite to the rotation direction (clockwise CW) of the input gear 41 when the vehicle equipped with unit 1 is traveling forward.

[0114] Here, when the input gear 41 rotates clockwise (CW) in Figure 11, as shown in Figure 12, an airflow Ar is generated along the tooth groove 412 of the outer circumference of the input gear 41, from one end 411a to the other end 411b of the tooth portion 411 (see arrow in the figure).

[0115] In this case, the direction of air Ar's movement is the direction of vector Fb, which is the result of combining vector Fx, which is in the direction along the tooth groove 412, and vector Fcw, which is in the direction along the rotational direction of the input gear 41. Therefore, when the vehicle equipped with unit 1 is moving forward, the rotation of the input gear 41 generates an airflow (airflow AC2) in the direction of vector Fb in the aforementioned region R to the side of the input gear 41.

[0116] Here, the vector Fcw in the direction along the rotational direction of the input gear 41 is greater than the vector Fx in the direction along the tooth groove 412. Therefore, the airflow (airflow AC2) generated by the rotation of the input gear 41, when viewed from the direction of the rotation axis X1, is in the direction along the tangent line L41b, as shown in Figure 11. The airflow AC2 moving along the tangent line L41b then moves across the diameter line Lr1 from top to bottom.

[0117] Therefore, by setting the opening direction of the inlet 820b to align with the tangent L41b of the virtual circle Im2, and oriented in the opposite direction to the clockwise direction CW of the input gear 41, the airflow AC2 can be efficiently drawn into the hollow portion 820 of the first passage 821 from the inlet 820b (see thick arrow in the figure).

[0118] As shown in Figures 5 and 7, the airflow AC2 taken into the hollow section 820 from the other end 82b of the second duct 82 is pushed by the airflow AC2 flowing in sequentially from the other end 82b, and moves through the first passage 821, the third passage 823, and the second passage 822 in order before being discharged from one end 82a.

[0119] As shown in Figure 13, one end 82a of the second duct 82 is positioned to overlap with the final gear 61 in the vertical direction. Furthermore, one end 82a of the second duct 82 is located on the vehicle-front side of the rotation axis X3 and below the rotation axis X3.

[0120] Viewed from the direction of the rotation axis X3, one end 82a of the second duct 82 faces the final gear 61 from the direction of the tangent L61b of the virtual circle Im1 along the outer surface 611c of the final gear 61. The one end 82a of the second duct 82 is a flat surface along the straight line Lb. The straight line Lb intersects the tangent L61b at a predetermined angle θ2.

[0121] The opening (discharge port 820a) that serves as the outlet from the hollow section 820 of the second duct 82 is positioned to face downstream in the direction of rotation (clockwise CW) of the final gear 61 when the vehicle equipped with unit 1 is traveling forward. Here, the opening direction of the discharge port 820a can be said to be the same direction as the rotation direction (clockwise CW) of the final gear 61 when the vehicle equipped with unit 1 is traveling forward. Viewed from the tangential L61b direction, the outlet 820a overlaps with the teeth 611 of the final gear 61.

[0122] Therefore, the airflow AC2 discharged from the outlet 820a is blown onto the teeth 611 of the final gear 61 from the tangential L61b direction. The direction of the airflow AC2 is aligned with the clockwise rotation CW of the final gear 61. As a result, the clockwise rotation CW of the final gear 61 is assisted by the airflow AC2 discharged from the second duct 82. Thus, the effect of air resistance can be reduced, and windage losses generated when the final gear 61 rotates can be reduced.

[0123] Here, as shown in Figure 13, one end 82a of the second duct 82 is a flat surface along a straight line Lb that is inclined by a predetermined angle θ2 with respect to the tangent L61b. The angle θ2 between the tangent L61b and the straight line Lb is acute. This allows the outlet 820a to be brought closer to the final gear 61 in the front-rear direction than, for example, if the angle θ2 were a right angle or an obtuse angle. This allows the airflow AC2 to be blown onto the final gear 61 more effectively.

[0124] In this way, by utilizing the airflow AC2 generated by the rotation of the input gear 41, it becomes possible to eliminate the need for a separate blower or other device to generate airflow. This helps to suppress an increase in the number of parts.

[0125] (Third duct) As shown in Figure 5, when viewed from above, the third duct 83 is a cylindrical member in which the first passage 831, the third passage 833, and the second passage 832 are connected in series. The inside of the third duct 83 is a hollow section 830 that connects one end 83a and the other end 83b.

[0126] Viewed from above, the first passage 831 of the third duct 83 is located on the motor case 11 side (upper side in the figure) of the large-diameter gear 51 and is oriented along the straight line Ln2. One end 83a of the third duct 83 is provided with an opening facing the straight line Ln2.

[0127] Viewed from above, the second passage 832 of the third duct 83 is located on the gear case 12 side (lower side in the figure) of the large-diameter gear 51 and is oriented along the straight line Ln4. The straight line Ln4 is inclined with respect to the straight line Ln1. The other end 83b of the second passage 832 is positioned to move closer to the straight line Ln1 as it moves away from the input gear 41 and towards the rear of the vehicle. Viewed from above, the other end 83b of the second passage 832 is positioned to overlap with the small diameter gear 52, and a portion of the other end 83b is positioned to overlap with the large diameter gear 51. The other end 83b of the third duct 83 is positioned to face the straight line Ln1.

[0128] Viewed from above, the first passage 831 and the second passage 832 are connected to each other via a third passage 833 that bypasses the input gear 41 side (front of the vehicle). Viewed from above, the third passage 833 is formed by connecting in series the following: a connection area 833a with the first passage 831; a first bypass area 833b extending in the vehicle longitudinal direction on the motor case 11 side (upper side in the figure) of the second duct 82; a second bypass area 833c extending in the direction of the rotation axis X1 on the vehicle front side of the second duct 82 and the input gear 41; and a third bypass area 833d extending in the vehicle longitudinal direction on the gear case 12 side (lower side in the figure) of the input gear 41.

[0129] The aforementioned first passage 831 is positioned close to the large-diameter gear 51. The first bypass region 833b is positioned far away from the input gear 41 toward the motor case 11 in order to avoid interference with the second duct 82 located to the side of the input gear 41. Therefore, when viewed from above, the connection region 833a is inclined to move closer to the motor case 11 as it moves toward the front of the vehicle, in order to connect the first passage 831, which is positioned offset in the direction of the rotation axis X1, with the first bypass region 833b.

[0130] The third bypass region 833d is located on the gear case 12 side of the input gear 41 and is oriented along the straight line Ln1. When viewed from above, the third bypass region 833d overlaps with the small-diameter gear 52 and connects to the second passage 832. Therefore, the third passage 833, which consists of the connection region 833a, the first bypass region 833b, the second bypass region 833c, and the third bypass region 833d connected in series, has a significantly curved shape when viewed from above, which bypasses the input gear 41 and the second duct 82.

[0131] In this embodiment, the third passage 833 of the third duct 83 is provided to bypass the front of the vehicle, rather than the lower or upper side of the input gear 41 and the second duct 82. The third duct 83 is provided in such a way that it avoids interference with the input gear 41 and the first duct 81 located above the second duct 82, and the second duct 82 located below it, while also preventing the unit 1 from becoming larger in the vertical direction.

[0132] As shown in Figure 2, when viewed from the direction of the rotation axis X2, the third duct 83 has a first passage 831 at one end 83a located below the large-diameter gear 51, and a second passage 832 at the other end 83b located above the large-diameter gear 51. Therefore, the third passage 833 of the third duct 83 is provided to cross the vehicle front side of the input gear 41 in the vertical direction.

[0133] Figure 14 is a diagram illustrating the third duct 83. Figure 14 is an enlarged view of area D in Figure 2. Figure 15 is a diagram illustrating the third duct 83. Figure 15 is a schematic diagram of the AA section of Figure 14. Figure 16 is a diagram illustrating the third duct 83. Figure 16 is an enlarged view of area C in Figure 5. Note that only the large-diameter gear 51, the small-diameter gear 52, and the third duct 83 are shown in Figure 16. Figure 17 is a diagram illustrating the third duct 83. Figure 17 is a schematic diagram of the AA section of Figure 16.

[0134] As shown in Figure 14, when viewed from the direction of the rotation axis X2, the first passage 831 of the third duct 83 is located on the outer diameter side of the teeth 511 of the large diameter gear 51.

[0135] One end 83a of the third duct 83 is a flat surface along the diameter line Lr2 passing through the rotation axis X2. The diameter line Lr2 is perpendicular to the virtual circle Im3 along the outer circumferential surface 511c of the large-diameter gear 51. The opening (inlet 830a) that serves as the entrance to the hollow section 830 of the third duct 83 is oriented in a direction along the tangent line L51a that is tangent to the virtual circle Im3.

[0136] Viewed from the direction of the rotation axis X2, the inlet 830a opens facing the upstream side of the rotation direction (counterclockwise, CCW) of the large-diameter gear 51 when the vehicle equipped with unit 1 is traveling forward. Here, the opening direction of the inlet 830a can be said to be opposite to the direction of rotation (counterclockwise, CCW) of the large-diameter gear 51 when the vehicle equipped with unit 1 is traveling forward.

[0137] Here, when the large-diameter gear 51 rotates counterclockwise (CCW), as shown in Figure 15, an airflow Ar is generated along the tooth groove 512 of the large-diameter gear 51, moving from one end 511a to the other end 511b of the tooth portion 511 (see arrow in the figure).

[0138] In this case, the direction of air Ar's movement is the direction of vector Fc, which is the result of combining vector Fx, which is in the direction along the tooth groove 512, and vector Fccw, which is in the direction along the rotational direction of the large-diameter gear 51. Therefore, when the vehicle equipped with unit 1 is moving forward, the rotation of the large-diameter gear 51 generates an airflow (airflow AC3) in the direction along the vector Fc in the aforementioned region R to the side of the large-diameter gear 51.

[0139] Here, the vector Fccw along the rotational direction of the large-diameter gear 51 is greater than the vector Fx along the tooth groove 512. Therefore, the airflow (airflow AC3) generated by the rotation of the large-diameter gear 51, when viewed from the direction of the rotation axis X2, is in the direction of the tangent line L51a, as shown in Figure 14. The airflow AC3 moving along the tangent line L51a then moves across the diameter line Lr2 from the rear to the front of the vehicle.

[0140] Therefore, by setting the opening direction of the inlet 830a to align with the tangent L51a of the virtual circle Im3, and oriented in the opposite direction to the counterclockwise direction CCW of the large-diameter gear 51, the airflow AC3 can be efficiently drawn into the hollow portion 830 of the first passage 831 from the inlet 830a (see hatched arrow in the figure).

[0141] As shown in Figures 5 and 7, the airflow AC3 taken into the hollow section 830 from one end 83a of the third duct 83 is pushed by the airflow AC3 flowing in sequentially from the end 83a side, and moves in order through the first passage 831, the third passage 833, and the second passage 832 before being discharged from the other end 83b.

[0142] As shown in Figure 16, the other end 83b of the third duct 83 is positioned to overlap with one end 511a of the teeth 511 of the large-diameter gear 51 in the vertical direction.

[0143] The second passage 832 is oriented along the straight line Ln4. The straight line Ln4 is inclined with respect to the straight line Ln1 and is perpendicular to the straight line Lm2 that runs along the teeth 511 of the large-diameter gear 51. Therefore, the discharge port 830b opens perpendicular to the teeth 511.

[0144] As shown in Figure 17, the second passage 832 on the other end 83b side of the third duct 83 is provided in a position that overlaps with the large-diameter gear 51 in the vertical direction. The other end 83b of the third duct 83 is located on the vehicle-front side of the rotation axis X2 and above the rotation axis X2.

[0145] Viewed from the direction of the rotation axis X2, the other end 83b of the third duct 83 faces the large-diameter gear 51 from the direction of the tangent L51b of the virtual circle Im3 along the outer circumferential surface 511c of the large-diameter gear 51. The other end 83b of the third duct 83 is a flat surface along the straight line Lc. The straight line Lc intersects the tangent L51b at a predetermined angle θ3.

[0146] The opening (discharge port 830b) that serves as the outlet from the hollow section 830 of the third duct 83 is positioned to face downstream in the direction of rotation (counterclockwise, CCW) of the large-diameter gear 51 when the vehicle equipped with unit 1 is traveling forward. Here, the opening direction of the discharge port 830b can be said to be the same as the rotation direction (counterclockwise, CCW) of the large-diameter gear 51 when the vehicle equipped with unit 1 is traveling forward. Viewed from the tangential L51b direction, the discharge port 830b overlaps with the teeth 511 of the large-diameter gear 51.

[0147] Therefore, the airflow AC3 discharged from the outlet 830b is blown onto the teeth 511 of the large-diameter gear 51 from the tangential L51b direction. The direction in which the airflow AC3 is blown is along the counterclockwise direction CCW of the large-diameter gear 51. As a result, the counterclockwise (CCW) rotation of the large-diameter gear 51 is assisted by the airflow AC3 discharged from the third duct 83. Therefore, the effect of air resistance can be reduced, and wind loss generated when the large-diameter gear 51 rotates can be reduced.

[0148] Here, as shown in Figure 17, the other end 83b of the third duct 83 is a flat surface along a straight line Lc that is inclined by a predetermined angle θ3 with respect to the tangent L51b. The angle θ3 between the tangent L51b and the straight line Lc is acute. This allows the outlet 830b to be brought closer to the large-diameter gear 51 in the vertical direction than, for example, if the angle θ3 were a right angle or an obtuse angle. This allows the airflow AC3 to be blown onto the large-diameter gear 51 more effectively.

[0149] Furthermore, as shown in Figure 16, in the third duct 83, the outlet 830b opens perpendicular to the straight line Lm2, which is the extending direction of the teeth 511. Therefore, the airflow AC3 discharged from the outlet 830b is blown onto the teeth 511 from a direction perpendicular to it. This allows the air pressure of the airflow AC3 to act effectively on the teeth 511.

[0150] In this way, by utilizing the airflow AC3 generated by the rotation of the large-diameter gear 51, it becomes possible to eliminate the need for, for example, a separate blower or other device to generate airflow. This helps to suppress an increase in the number of parts.

[0151] In this embodiment, as shown in Figure 9, the entire inlet 810a of the first duct 81 is offset from (does not overlap with) the final gear 61 when viewed from the radial direction of the rotation axis X3, but the embodiment is not limited to this. It is sufficient that at least a part of the inlet 810a is offset. Furthermore, since the air velocity Ar is higher in the region R offset from the final gear 61 (see Figure 4), it is preferable to offset a larger area of ​​the inlet 810a from the final gear 61.

[0152] Furthermore, as shown in Figure 12, the entire inlet 820b of the second duct 82 is offset from (does not overlap with) the input gear 41 when viewed from the radial direction of the rotation axis X1, but the configuration is not limited to this. It is sufficient that at least a part of the inlet 820b is positioned to be offset. Furthermore, since the air velocity Ar is higher in the region R offset from the input gear 41, it is preferable to offset a larger area of ​​the inlet 820b from the input gear 41.

[0153] Furthermore, as shown in Figure 15, an example is shown in which the entire inlet 830a of the third duct 83 is offset (does not overlap) with the large-diameter gear 51 when viewed from the radial direction of the rotation axis X2, but the configuration is not limited to this. It is sufficient that at least a part of the inlet 830a is offset. Furthermore, since the air velocity Ar is higher in the region R offset from the large-diameter gear 51, it is preferable to offset a larger area of ​​the inlet 830a from the large-diameter gear 51.

[0154] The following are examples of Unit 1 in a certain aspect of the present invention. (1-1) Unit 1 is, The device includes a first duct 81 (duct section) which has an inlet 810a through which an airflow AC1 generated by the rotation of the final gear 61 (gear) of the differential mechanism 6 is introduced, and a hollow section 810 (supply section) through which the airflow AC1 introduced from the inlet 810a flows (is supplied).

[0155] With this configuration, the airflow AC1 generated by the rotation of the final gear 61 can be utilized using the first duct 81. Therefore, a separate blower for generating airflow can be eliminated. This helps to suppress an increase in the number of parts.

[0156] (1-2) Unit 1 is, The second duct 82 (duct section) has an inlet 820b through which an airflow AC2 generated by the rotation of the input gear 41 (gear) of the input shaft 4 is introduced, and a hollow section 820 (supply section) through which the airflow AC2 introduced from the inlet 820b flows (is supplied).

[0157] With this configuration, the airflow AC2 generated by the rotation of the input gear 41 can be utilized using the second duct 82. Therefore, a separate blower for generating airflow can be eliminated. This helps to suppress an increase in the number of parts.

[0158] (1-3) Unit 1 is, The duct section 8 has a third duct 83 (duct section) which includes an inlet 830a through which an airflow AC3 generated by the rotation of a large-diameter gear 51 of the gear section 55 (gear) of the intermediate shaft 5 is introduced, and a hollow section 830 (supply section) through which the airflow AC3 introduced from the inlet 830a flows (is supplied).

[0159] With this configuration, the airflow AC3 generated by the rotation of the large-diameter gear 51 can be utilized using the third duct 83. Therefore, a separate blower for generating airflow can be eliminated. This helps to suppress an increase in the number of parts.

[0160] (2-1) In the above (1-1), Final Gear 61 is a gear. The inlet 810a of the first duct 81 is located on the other end 611b side of the teeth 611 of the final gear 61 (the end of the meshing of the helical gear).

[0161] Through diligent research, the inventors have discovered that in the final gear 61, which is a helical gear, an airflow AC1 is generated that flows from one end 611a (meshing start side) of the tooth portion 611 toward the other end 611b (meshing end side). Therefore, by configuring it as described above and positioning the inlet 810a of the first duct 81 on the other end 611b side of the toothed portion 611, the airflow AC1 can be taken in more efficiently.

[0162] (2-2) In the above (1-2), The input gear 41 is a helical gear. The inlet 820b of the second duct 82 is located on the other end 411b side of the teeth 411 of the input gear 41 (the end of the meshing of the helical gear).

[0163] Through diligent research, the inventors have discovered that in the input gear 41, which is a helical gear, an airflow AC2 is generated that flows from one end 411a (meshing start side) of the tooth portion 411 toward the other end 411b (meshing end side). Therefore, by configuring it as described above and positioning the inlet 820b of the second duct 82 on the other end 411b side of the toothed portion 411, the airflow AC2 can be taken in more efficiently.

[0164] (2-3) In the above (1-3), The large-diameter gear 51 and small-diameter gear 52 of the gear section 55 are helical gears. The inlet 830a of the third duct 83 is located on the other end 511b side of the teeth 511 of the large-diameter gear 51 (the end of the meshing of the helical gear).

[0165] Through diligent research, the inventors have discovered that in a large-diameter gear 51, which is a helical gear, an airflow AC3 is generated that flows from one end 511a (meshing start side) of the tooth portion 511 toward the other end 511b (meshing end side). Therefore, by configuring it as described above and positioning the inlet 830a of the third duct 83 on the other end 511b side of the toothed portion 511, the airflow AC3 can be taken in more efficiently.

[0166] (3-1) In the above (1-1) or (2-1), Viewed from the direction of the rotation axis X3 (in axial view), The opening direction of the inlet 810a of the first duct 81 is set to be aligned with the direction of the tangent L61a of the virtual circle Im1 (outer circle) that is aligned with the outer surface 611c of the teeth 611 of the final gear 61.

[0167] The airflow AC1 has a strong vector in the tangential L61a direction. Therefore, by configuring it as described above, the airflow AC1 can be taken into the first duct 81 more efficiently.

[0168] (3-2) In the above (1-2) or (2-2), Viewed from the direction of the rotation axis X1 (in axial view), The opening direction of the inlet 820b of the second duct 82 is set to be aligned with the direction of the tangent L41b of the virtual circle Im2 (outer circle) along the outer surface 411c of the teeth 411 of the input gear 41.

[0169] The airflow AC2 has a strong vector in the tangential L41b direction. Therefore, by configuring it as described above, the airflow AC2 can be taken into the second duct 82 more efficiently.

[0170] (3-3) In the above (1-3) or (2-3), Viewed from the direction of the rotation axis X2 (in axial view), The opening direction of the inlet 830a of the third duct 83 is set to be aligned with the direction of the tangent L51a of the virtual circle Im3 (outer circle) that is aligned with the outer surface 511c of the teeth 511 of the large diameter gear 51.

[0171] The airflow AC3 has a strong vector in the tangential L51a direction. Therefore, by configuring it as described above, the airflow AC3 can be taken into the third duct 83 more efficiently.

[0172] (4-1) In any of the above (1-1) to (3-1), Viewed from the radial direction of the rotation axis X3 (in radial view), The inlet 810a of the first duct 81 has a portion that does not overlap with the teeth 611 of the final gear 61.

[0173] Through diligent research, the inventors discovered that, when viewed from the radial direction of the rotation axis X3, the wind speed in the region R that does not overlap with the final gear 61 is stronger than the portion that overlaps with the final gear 61 (see Figure 4). Therefore, by configuring it as described above and placing at least a portion of the inlet 810a of the first duct 81 in a region R (see Figure 9) that does not overlap with the final gear 61 when viewed from the radial direction of the rotation axis X3, the airflow AC1 can be taken into the first duct 81 more efficiently.

[0174] (4-2) In any of the above (1-2) to (3-2), Viewed from the radial direction of the rotation axis X1 (in radial view), The inlet 820b of the second duct 82 has a portion that does not overlap with the teeth 411 of the input gear 41.

[0175] Through diligent research, the inventors have discovered that, when viewed from the radial direction of the rotation axis X1, the wind speed in the region R that does not overlap with the input gear 41 is stronger than the wind speed in the region that does not overlap with the input gear 41. Therefore, by configuring it as described above and placing at least a portion of the inlet 820b of the second duct 82 in a region R (see Figure 12) that does not overlap with the input gear 41 when viewed from the radial direction of the rotation axis X1, the airflow AC2 can be taken into the second duct 82 more efficiently.

[0176] (4-3) In any of the above (1-3) to (3-3), Viewed from the radial direction of the rotation axis X2 (in radial view), The inlet 830a of the third duct 83 has a portion that does not overlap with the teeth 511 of the large-diameter gear 51.

[0177] Through diligent research, the inventors have found that, when viewed from the radial direction of the rotating shaft X2, the wind speed in the region R that does not overlap with the large-diameter gear 51 is stronger compared to the region that overlaps with the large-diameter gear 51. Therefore, by configuring it as described above and placing at least a portion of the inlet 830a of the third duct 83 in a region R (see Figure 15) that does not overlap with the large-diameter gear 51 when viewed from the radial direction of the rotation axis X2, the airflow AC3 can be taken into the third duct 83 more efficiently.

[0178] (5-1) In any of the above (1-1) to (4-1), The opening direction of the inlet 810a of the first duct 81 is set to be opposite to the clockwise direction CW (direction of rotation) of the final gear 61.

[0179] The airflow AC1 has a vector Fx that travels from one end 611a (meshing start side) to the other end 611b (meshing end side) of the teeth 611 (see Figure 9). Therefore, for example, even if the opening direction of the inlet 810a of the first duct 81 is perpendicular to the rotation direction of the final gear 61 (for example, along the rotation axis X3), it is still possible to take in the airflow AC1 from the first duct 81. However, the airflow AC1 has a strong vector Fcw in the clockwise direction CW of the final gear 61 (see Figure 9). Therefore, by configuring it as described above and setting the opening direction of the inlet 810a of the first duct 81 to be opposite to the clockwise direction CW of the final gear 61, the airflow AC1 can be taken in more efficiently.

[0180] (5-2) In any of the above (1-2) to (4-2), The opening direction of the inlet 820b of the second duct 82 is set to be opposite to the clockwise direction CW (direction of rotation) of the input gear 41.

[0181] The airflow AC2 has a vector Fx that travels from one end 411a (meshing start side) to the other end 411b (meshing end side) of the teeth 411 (see Figure 12). Therefore, for example, even if the opening direction of the inlet 820b of the second duct 82 is perpendicular to the rotation direction of the input gear 41 (for example, along the rotation axis X1), it is still possible to take in the airflow AC2 from the second duct 82. However, the airflow AC2 has a strong vector Fcw in the clockwise direction CW of the input gear 41 (see Figure 12). Therefore, by configuring it as described above and setting the opening direction of the inlet 820b of the second duct 82 to be opposite to the clockwise direction CW of the input gear 41, the airflow AC2 can be taken in more efficiently.

[0182] (5-3) In any of the above (1-3) to (4-3), The opening direction of the inlet 830a of the third duct 83 is set to be opposite to the counterclockwise direction (CCW) (direction of rotation) of the large-diameter gear 51.

[0183] The airflow AC3 has a vector Fx that travels from one end 511a (meshing start side) to the other end 511b (meshing end side) of the teeth 511 (see Figure 15). Therefore, for example, even if the opening direction of the inlet 830a of the third duct 83 is perpendicular to the rotation direction of the large-diameter gear 51 (for example, along the rotation axis X2), it is still possible to take in the airflow AC3 from the third duct 83. However, the airflow AC3 has a strong counterclockwise vector Fccw of the large-diameter gear 51. Therefore, by configuring it as described above and setting the opening direction of the inlet 830a of the third duct 83 to face the counterclockwise direction CCW of the large-diameter gear 51, the airflow AC3 can be taken in more efficiently.

[0184] (7-1) In any of the above (1-1) to (5-1), The final gear 61 (gear) meshes with the small-diameter gear 52 of the other gear, which is the gear section 55 (first gear). The large-diameter gear 51 of the gear section 55 (first gear) meshes with another gear, the input gear 41 (second gear). Airflow AC1 is supplied from the hollow section 810 of the first duct 81 to the input gear 41. The outlet 810b (supply port) of the hollow section 810 of the first duct 81 opens in a direction aligned with the clockwise direction CW (direction of rotation) of the input gear 41.

[0185] When the input gear 41 rotates, windage loss occurs due to air resistance. However, since the airflow AC1 discharged from the first duct 81 is blown in a direction that reduces the air resistance acting on the input gear 41, windage loss of the input gear 41 can be reduced. Furthermore, since the rotation direction of the final gear 61 and the input gear 41 is the same clockwise direction (CW), the overall length of the first duct 81 can be shortened. For example, if we were to attempt to blow the airflow AC1 generated by the rotation of the final gear 61 onto a gear section 55 (large-diameter gear 51 or small-diameter gear 52) that rotates in the opposite direction to the final gear 61, we would need to devise a way to route the first duct 81 so that the direction of the airflow AC1 is aligned with the rotation direction of the gear section 55. This would involve routing the first duct 81 far to the front (see Figure 2, for example), and then making a U-turn to bypass the input gear 41. In this case, the overall length of the first duct 81 would likely increase. As a result of the increased length of the first duct 81, the force of the airflow AC1 would be more easily reduced. Therefore, by configuring it as described above, it becomes easier to maintain the momentum of the airflow AC1 when it is taken into the first duct 81, and windage loss can be effectively reduced.

[0186] (7-2) In any of the above (1-2) to (5-2), The input gear 41 meshes with the large-diameter gear 51 of the gear section 55 (first gear), which is another gear. The small-diameter gear 52 of the gear section 55 (first gear) meshes with another gear, the final gear 61 (second gear). Airflow AC2 is supplied from the hollow section 820 of the second duct 82 to the final gear 61. The outlet 820a (supply port) of the hollow section 820 of the second duct 82 opens in a direction aligned with the clockwise direction CW (direction of rotation) of the final gear 61.

[0187] When the final gear 61 rotates, windage losses occur due to air resistance. However, by configuring it as described above, the airflow AC2 discharged from the second duct 82 is blown in a direction that reduces the air resistance acting on the final gear 61, thereby reducing the windage loss of the final gear 61. Furthermore, since the rotation direction of the final gear 61 and the input gear 41 is the same clockwise direction (CW), the overall length of the second duct 82 can be shortened. For example, if we were to attempt to blow the airflow AC2 generated by the rotation of the input gear 41 onto a gear section 55 (large-diameter gear 51 or small-diameter gear 52) that rotates in the opposite direction to the input gear 41, we would need to devise a way to route the second duct 82 so that the direction of the airflow AC2 is aligned with the rotation direction of the gear section 55. This would involve routing the second duct 82 far to the rear (see, for example, Figure 2), and then making a U-turn to bypass the final gear 61. In this case, the overall length of the second duct 82 would likely increase. As a result of the increased length of the second duct 82, the force of the airflow AC2 would be more easily reduced. Therefore, by configuring it as described above, it becomes easier to maintain the momentum of the airflow AC2 when it is taken into the second duct 82, and windage loss can be effectively reduced.

[0188] (8) In any of the above (1-3) to (5-3), Airflow AC3 is supplied from the hollow section 830 (supply section) of the third duct 83 to the large-diameter gear 51 of the gear section 55 (gear). The outlet 830b (supply port) of the hollow section 830 of the third duct 83 opens in a direction aligned with the counterclockwise direction (CCW) (direction of rotation) of the large-diameter gear 51.

[0189] In this case, it is necessary to make a U-turn in the third duct 83, but by making a U-turn and placing another component such as an adjacent gear (for example, input gear 41) in the enclosed area, the loss due to the air resistance of the gear section 55 itself can be reduced by the airflow AC3 generated by the rotation of the gear section 55 itself, without interference with other components.

[0190] (Variation 1) In the embodiments described above, as shown in Figure 5, an example was given in which one end 81a of the first duct 81 and one end 83a of the third duct 83 open in directions perpendicular to the rotation axes X3 and X2, respectively. Also, as shown in Figure 12, an example was given in which the other end 82b of the second duct 82 opens in a direction perpendicular to the rotation axis X2. However, the opening direction of each inlet is not limited to the embodiments described above. For example, the inlet may open in a direction along a vector obtained by combining the vector in the direction along the tooth groove and the vector in the direction along the rotation direction of the gear.

[0191] Figure 18 is a diagram illustrating unit 1A according to modified example 1. In Figure 18, the teeth 511 below the rotation axis X2 (towards the back of the page) are shown with a dashed line to make it easier to understand the positional relationship. Figure 19 is a diagram illustrating unit 1A according to modified example 1. Figure 19 is a schematic diagram of cross-section AA in Figure 18. In Figure 19, the vertical direction corresponds to the vertical line direction. In the following description, components similar to those in the embodiment will be denoted by the same reference numerals, and detailed explanations will be omitted.

[0192] As shown in Figure 18, the duct section 8A of unit 1A according to modified example 1 is composed of three ducts (first duct 81A, second duct 82A, and third duct 83A). The first duct 81A to the third duct 83A are cylindrical members with one end and the other end open in the longitudinal direction.

[0193] Viewed from above, the first passage 811A of the first duct 81A is provided on the motor case 11 side (upper side in the figure) of the final gear 61, oriented along the straight line Ln5. The straight line Ln5 is oriented along the vector Fa, which is the result of combining the vector Fx in the direction along the tooth groove 612 and the vector Fcw in the direction along the rotational direction of the final gear 61.

[0194] Straight line Ln5 is inclined with respect to straight line Ln3. One end 81a of the first passage 811A is positioned to approach straight line Ln3 as it moves from the second passage 812 towards the rear of the vehicle. When viewed from above, a portion of one end 81a of the first passage 811A is positioned to overlap with the other end 611b of the teeth 611 of the final gear 61.

[0195] Viewed from the radial direction of the rotation axis X3, the inlet 810a of the first duct 81A opens in a direction opposite to the airflow (airflow AC1) in the direction along vector Fa. In other words, the inlet 810a of the first duct 81A opens in a direction opposite to the clockwise direction CW (direction of rotation) of the final gear 61, and also opposite to the direction from one end 611a to the other end 611b of the teeth 611 of the final gear 61 (direction of the rotation axis X3).

[0196] In this way, by opening the inlet 810a in a direction opposite to the airflow (airflow AC1) along the vector Fa, the inlet 810a can be set at an angle to the clockwise direction CW and the rotation axis X3 direction of the final gear 61. This allows for more efficient intake of the airflow AC1 (see the white arrow in Figure 18). Note that one end 81a of the first passage 811A may be offset from the other end 611b of the tooth portion 611.

[0197] Viewed from above, the first passage 831A of the third duct 83A is located on the motor case 11 side (upper side in the figure) of the large-diameter gear 51 and is oriented along the straight line Ln6. The first passage 831A is connected to the first bypass region 833b described above. The straight line Ln6 is oriented along the vector Fc, which is a combination of the vector Fx oriented along the tooth groove 512 described above and the vector Fccw oriented along the rotational direction of the large-diameter gear 51.

[0198] The straight line Ln6 is inclined with respect to the straight line Ln1. One end 83a of the first passage 831A is positioned to approach the straight line Ln1 as it moves from the first bypass region 833b toward the rear of the vehicle. Viewed from above, one end 83a of the first passage 831A is offset from the other end 511b of the teeth 511 of the large-diameter gear 51.

[0199] Viewed from the radial direction of the rotation axis X2, the inlet 830a of the third duct 83A opens in a direction opposite to the airflow (airflow AC3) in the direction along vector Fc. In other words, the inlet 830a of the third duct 83A opens in a direction opposite to the counterclockwise direction CCW (direction of rotation) of the large-diameter gear 51, and also opposite to the direction from one end 511a to the other end 511b of the teeth 511 of the large-diameter gear 51 (direction of the rotation axis X2).

[0200] In this way, by opening the inlet 830a in a direction opposite to the airflow (airflow AC3) in the direction along vector Fc, the inlet 830a can be set at an angle to the counterclockwise direction CCW and the rotation axis X2 direction of the large-diameter gear 51. This allows for more efficient intake of the airflow AC3 (see hatched arrow in Figure 18). Note that, when viewed from above, a portion of one end 83a of the first passage 831A may overlap with the other end 511b of the tooth portion 511.

[0201] Furthermore, as shown in Figure 19, when viewed from the radial direction of the rotation axis X1, the first passage 821A of the second duct 82A has a bent portion 825 at the other end 82b that bends toward the input gear 41. The bent portion 825 is provided in a direction along the straight line Ln7. The straight line Ln7 is in the direction along the vector Fb, which is the result of combining the vector Fx in the direction along the tooth groove portion 412 and the vector Fcw in the direction along the rotation direction of the input gear 41.

[0202] The straight line Ln7 is inclined with respect to the straight line VLa that runs in the vertical direction. The bent portion 825 is positioned to approach the input gear 41 as it moves upward. When viewed from the radial direction of the rotation axis X1, a portion of the other end 82b of the bent portion 825 is positioned to overlap with the other end 411b of the teeth 411 of the input gear 41.

[0203] Viewed from the radial direction of the rotation axis X1, the inlet 820b of the second duct 82A opens in a direction opposite to the airflow (airflow AC2) in the direction along vector Fb. In other words, the inlet 820b of the second duct 82A opens in a direction opposite to the clockwise direction CW (direction of rotation) of the input gear 41, and also opposite to the direction from one end 411a to the other end 411b of the teeth 411 of the input gear 41 (direction of the rotation axis X1).

[0204] In this way, by opening the inlet 820b in a direction opposite to the airflow (airflow AC2) along the vector Fb, the inlet 820b can be set at an angle to the clockwise direction CW and the rotation axis X1 direction of the input gear 41. This allows for more efficient intake of the airflow AC2 (see the thick arrow in Figure 19). Note that the other end 82b of the bent portion 825 may be offset from the other end 411b of the tooth portion 411.

[0205] Furthermore, as shown in Figure 18, when viewed from above, the second passage 822A of the second duct 82A is located on the gear case 12 side of the straight line Ln3. The second passage 822A has a bent portion 826 at one end 82a, which is bent from the gear case 12 side (lower side in the figure) toward the final gear 61. The bent portion 826 is provided in a direction along the straight line Ln8. The straight line Ln8 is perpendicular to the straight line Lm3 which is along the extending direction of the teeth 611 (see dashed line in the figure) in the region below the rotation axis X3 (backward side in the figure). Therefore, the outlet 820a of the second duct 82A opens in a direction perpendicular to the teeth 611.

[0206] The exhaust port 820a is positioned to overlap with the final gear 61 in the vertical direction. Therefore, the airflow AC2 discharged from the exhaust port 820a is blown onto the teeth 611 from a direction perpendicular to it. This allows the air pressure of the airflow AC2 to act effectively on the teeth 611.

[0207] The unit 1A relating to the modified example 1 has the following configuration. (6-1) The opening direction of the inlet 810a of the first duct 81A is opposite to the clockwise direction CW (direction of rotation) of the final gear 61, and is opposite to the rotation axis X3, which is the direction from one end 611a (meeting start side) to the other end 611b (meeting end side) of the teeth 611 of the final gear 61.

[0208] The direction of movement of the airflow AC1 is along the vector Fa, which is the result of combining the vector Fcw in the clockwise direction CW of the final gear 61 and the vector Fx in the direction along the tooth groove 612 (see Figure 18). Therefore, by configuring it as described above, the inlet 810a can be opened in a direction along the vector Fa. In this way, by setting the inlet 810a at an angle to the clockwise direction CW and the rotation axis X3 direction of the final gear 61, the airflow AC1 can be taken in more efficiently.

[0209] (6-2) The opening direction of the inlet 820b of the second duct 82A is opposite to the clockwise direction CW (direction of rotation) of the input gear 41, and is opposite to the rotation axis X1, which is the direction from one end 411a (meshing start side) to the other end 411b (meshing end side) of the teeth 411 of the input gear 41.

[0210] The direction of movement of the airflow AC2 is along the vector Fb, which is the result of combining the vector Fcw in the clockwise direction CW of the input gear 41 and the vector Fx in the direction along the tooth groove 412 (see Figure 19). Therefore, by configuring it as described above, the inlet 820b can be opened in a direction aligned with the vector Fb. In this way, by setting the inlet 820b at an angle to the clockwise direction CW and the rotation axis X1 direction of the input gear 41, the airflow AC2 can be taken in more efficiently.

[0211] (6-3) The opening direction of the inlet 830a of the third duct 83A is opposite to the counterclockwise direction CCW (direction of rotation) of the large diameter gear 51, and is opposite to the rotation axis X2, which is the direction from one end 511a (meshing start side) to the other end 511b (meshing end side) of the teeth 511 of the large diameter gear 51.

[0212] The direction of movement of the airflow AC3 is along the vector Fc, which is the result of combining the vector Fccw in the counterclockwise direction CCW of the large-diameter gear 51 and the vector Fx in the direction along the tooth groove 512 (see Figure 18). Therefore, by configuring it as described above, the inlet 830a can be opened in a direction aligned with the vector Fc. In this way, by setting the inlet 830a at an angle to the counterclockwise direction CCW and the rotation axis X2 direction of the large-diameter gear 51, the airflow AC3 can be taken in more efficiently.

[0213] (Modification 2) In the embodiments and modified example 1 described above, we have illustrated a configuration in which airflows AC1 to AC3 flow through the duct section 8 (first duct 81 to third duct 83), respectively. In the modified version 2, unit 1B utilizes the airflow AC1 to AC3 passing through the first duct 81 to the third duct 83 for power generation.

[0214] Figure 20 is a diagram illustrating unit 1B according to modified example 2. In Figure 20, a portion of the first duct 81 to the third duct 83 is cut out to expose the internal components 911 to 931. Figure 21 is a diagram illustrating unit 1B related to modified example 2. Figure 21 is a schematic diagram of the AA cross-section of Figure 20.

[0215] As shown in Figure 20, in the modified example 2, unit 1B is provided in the duct section 8, and the power generation section 9 includes a first generator 91 (generator) provided in the first duct 81, a second generator 92 (generator) provided in the second duct 82, and a third generator 93 (generator) provided in the third duct 83.

[0216] The first generator 91 includes a power generation coil 910 and a turbine 911 that generates an induced current in the coil 910. The coil 910 is electrically connected to the battery BT via the wiring Ha.

[0217] The turbine 911 has a shaft portion 912 with one end inserted into the coil 910 and a blade portion 913 provided at the other end of the shaft portion 912. The blade portion 913 is located within the hollow portion 810 of the first duct 81. The shaft portion 912 penetrates the first duct 81 from the outside to the inside. The shaft portion 912 is rotatably supported by the first duct 81. Therefore, an air current AC1 passing through the first duct 81 is supplied to the blade portion 913 of the turbine 911.

[0218] The second generator 92 includes a power generation coil 920 and a turbine 921 that generates an induced current in the coil 920. The coil 920 is electrically connected to the battery BT via the wiring Hb.

[0219] The turbine 921 has a shaft portion 922 with one end inserted into the coil 920 and a blade portion 923 provided at the other end of the shaft portion 922. The blade portion 923 is located within the hollow portion 820 of the second duct 82. The shaft portion 922 penetrates the second duct 82 from the outside to the inside. The shaft portion 922 is rotatably supported by the second duct 82. Therefore, an air current AC2 passing through the second duct 82 is supplied to the blade portion 923 of the turbine 921.

[0220] The third generator 93 includes a power generation coil 930 and a turbine 931 that generates an induced current in the coil 930. The coil 930 is electrically connected to the battery BT via the wiring Hc.

[0221] The turbine 931 has a shaft portion 932 with one end inserted into the coil 930, and a blade portion 933 provided at the other end of the shaft portion 932. The blade portion 933 is located within the hollow portion 830 of the third duct 83. The shaft portion 932 penetrates the third duct 83 from the outside to the inside. The shaft portion 932 is rotatably supported by the third duct 83. Therefore, the blade portion 933 of the turbine 931 is supplied with the air flow AC3 passing through the third duct 83.

[0222] The turbines 911 of the first generator 91, the turbines 921 of the second generator 92, and the turbines 931 of the third generator 93 have the same configuration. In the following description, taking the turbine 911 of the first generator 91 as an example, the configuration of each part of the turbine 911 will be described.

[0223] As shown in FIG. 21, the blade portion 913 of the turbine 911 is provided on the outer peripheral surface 912a of the shaft portion 912. The blade portions 913 are provided over the entire circumference of the outer peripheral surface 912a of the shaft portion 912 at intervals in the circumferential direction around the axis C91 of the shaft portion 912. The blade portions 913 are provided so as to be integrally rotatable with the shaft portion 912.

[0224] The plurality of blade portions 913 are provided radially from the axis C91 of the shaft portion 912. In the direction of the straight line L91 along the radial direction, the blade portion 913 has a concave portion 913b in which the region between the outer peripheral surface 913a and the shaft portion 912 is recessed on one side in the circumferential direction around the axis C91.

[0225] Therefore, when the air flow AC1 passing through the first duct 81 contacts the blade portion 913 of the turbine 911, the pressure of the air flow AC1 acts on the concave portion 913b of the blade portion 913. As a result, the blade portion 913 and the shaft portion 912 rotate in one direction (the clockwise direction CW in FIG. 21) in the circumferential direction around the axis C91.

[0226] Here, as shown in Figure 20, a magnet (not shown) is provided in the region of the shaft portion 912 that is inserted into the coil 910. When the magnet rotates in accordance with the rotation of the shaft portion 912, the magnetic field inside the coil 910 changes, and an electric current is generated in the coil 910. The electric current generated in the coil 910 moves to the battery BT side via the wiring Ha. As a result, the battery BT is charged.

[0227] As shown in Figure 20, the same applies to turbine 921 in the second duct 82 and turbine 931 in the third duct 83. That is, the rotation of turbines 921 and 931 generates current in coils 920 and 930. The current generated in coils 920 and 930 moves to the battery BT side via wiring Hb and Hc. This charges the battery BT.

[0228] In this way, by providing the first generator 91 to the third generator 93 in the first duct 81 to the third duct 83, the airflow AC1 to AC3 generated by the rotation of each gear can be used for power generation.

[0229] The unit 1B relating to the modified example 2 has the following configuration. (9-1) Airflow AC1 is supplied from the first duct 81 (duct section) to the turbine 911 of the first generator 91 (generator).

[0230] This configuration makes it possible to generate electricity using airflow AC1 (wind power).

[0231] (9-2) Airflow AC2 is supplied from the second duct 82 (duct section) to the turbine 921 of the second generator 92 (generator).

[0232] This configuration makes it possible to generate electricity using airflow AC2 (wind power).

[0233] (9-3) Airflow AC3 is supplied from the third duct 83 (duct section) to the turbine 931 of the third generator 93 (generator).

[0234] This configuration makes it possible to generate electricity using airflow AC3 (wind power).

[0235] (Variation 3) Figure 22 is a diagram illustrating unit 1C related to modified example 3. Furthermore, in the above-described embodiments and modifications 1 and 2, examples were given in which the first ducts 81, 81A to the third ducts 83, 83A are integrally formed cylindrical members. However, the invention is not limited to this embodiment.

[0236] For example, as shown in Figure 22, the first duct 81B may be formed by combining two case members 818 and 819. In this case, for example, case member 818 can be fixed to the motor case 11 (see Figure 1), and case member 819 can be fixed to the gear case 12 (see Figure 1). As a result, the first duct 81B is formed by assembling the case members 818 and 819 together with the joining of the motor case 11 and the gear case 12. This reduces the effort required to assemble the first duct 81B to the motor case 11 as a separate process. Although not shown in the diagram, the second duct 82 and the third duct 83 can also be similarly composed of two case members.

[0237] Furthermore, in the above-described modified example 3, the first duct 81B is provided separately from the housing HS, but the invention is not limited to this embodiment. For example, recesses corresponding to the shapes of the case members 818 and 819 of the first duct 81B may be formed on the opposing surfaces of the motor case 11 and the gear case 12, respectively. By joining the motor case 11 and the gear case 12 in this way, a hollow portion 810 is formed by the recesses on the motor case 11 side and the recesses on the gear case 12 side.

[0238] In addition, in the above-described embodiments and Modifications 1 to 3, the case where the first duct 81 to the third duct 83 are cylindrical members having a constant flow path cross-sectional area over the entire length has been exemplified. However, it is not limited to this aspect. For example, in order to increase the discharge speed (spraying speed) of the airflow from the discharge port, a throttle for narrowing the flow path cross-sectional area may be provided in the duct.

[0239] The above-described Modifications 1 to 3 can be applied not only to the embodiment but also at least part of each content can be applied to the embodiment and other modifications. It is also possible.

[0240] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to only the aspects shown in these embodiments. It can be appropriately changed within the scope of the technical idea of the invention.

Explanation of Reference Numerals

[0241] 1, 1A, 1B, 1C: Unit 2: Motor 3: Power transmission mechanism 4: Input shaft 5: Intermediate shaft 6: Differential mechanism 7, 7A, 7B: Drive shaft 8, 8A: Duct part 9: Power generation part 41: Input gear 411: Tooth part 412: Tooth groove part 411a: One end (meshing start) 411b: The other end (meshing end) 51: Large-diameter gear 511: Tooth part 512: Tooth groove part 511a: One end (meshing start) 511b: The other end (meshing end) 52: Small-diameter gear 55: Gear part 61: Final gear 611: Tooth part 612: Tooth groove part 611a: One end (start of engagement) 611b: Other end (end of engagement) 81, 81A, 81B: First duct 810: Hollow part (supply part) 810a: Inlet 810b: Discharge port (supply port) 82, 82A: Second duct 820: Hollow part (supply part) 820a: Discharge port (supply port) 820b: Inlet 83, 83A: Third duct 830: Hollow part (supply part) 830a: Inlet 820b: Discharge port (supply port) 91: First Generator 92: Second Generator 93: Third Generator 911: Turbine 921: Turbine 931: Turbine AC1: Airflow (wind power) AC2: Airflow (wind power) AC3: Airflow (wind power) Ar: air CW: Direction of rotation CCW: Direction of rotation In1: Virtual circle (outer circle) In2: Virtual circle (outer circle) Im3: Virtual circle (outer circle) L61a: Tangent L41b: Tangent L51a: Tangent X, X1, X2, X3: Rotation axis

Claims

1. Gears and A unit having a duct section which includes an inlet into which airflow generated by the rotation of the gear is introduced, and a supply section which supplies the airflow introduced from the inlet.

2. In claim 1, The aforementioned gear is a helical gear, The aforementioned inlet is a unit located on the end of the meshing of the helical gear.

3. In claim 2, In an axial view, the opening direction of the inlet is set to be aligned with the tangential direction of the outer circumference of the helical gear.

4. In claim 2, In a radial view, the inlet has a portion that does not overlap with the helical gear, in the unit.

5. In claim 2, The opening direction of the inlet is set to be opposite to the rotation direction of the helical gear in the unit.

6. In claim 2, The opening direction of the inlet is set to be opposite to the rotation direction of the helical gear and opposite to the direction from the meshing start side to the meshing end side of the helical gear.

7. In claim 1, It has a first gear that meshes with the aforementioned gear, and a second gear that meshes with the aforementioned first gear, Airflow is supplied from the supply section of the duct to the second gear. The supply port of the supply section of the duct section is open in a direction along the rotational direction of the second gear, in the unit.

8. In claim 1, Airflow is supplied from the supply section of the duct to the gear. The supply port of the supply section of the duct section is open in a direction along the rotation direction of the gear, in the unit.

9. In claim 1, A unit in which airflow is supplied from the aforementioned duct section to the turbine of a generator.

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