Gear, speed reducer and vehicle

Abstract

To provide a gear capable of reducing transmission loss of power due to pumping of lubricating oil when the lubricating oil is supplied from a meshing start side in proper high-speed rotation.SOLUTION: A gear which is used while meshing with another gear and supplied with lubricating oil from a meshing start side has: a base part which has a root circle defining a root circle diameter, a plurality of tooth parts provided at designated intervals in the circumference direction of the root circle of the base part, and a recessed part recessed in the root circle between mutually adjacent tooth parts of the plurality of tooth parts and receiving the lubricating oil from the meshing start side.SELECTED DRAWING: Figure 7B

Description

[Technical Field]

[0001] The present invention relates to a gear, a reducer, and a vehicle. [Background technology]

[0002] For example, motors for electric vehicles (EVs) are becoming faster and faster. The high-speed rotating gears that are driven by the high-speed rotation of the motors are lubricated and cooled by lubricating oil sprayed onto the tooth surfaces.

[0003] There are two typical locations for spraying lubricating oil: from the beginning of meshing and from the disengagement side, toward the meshing point of the gears. When lubricating oil is supplied from the beginning of meshing, a large amount of lubricating oil is generally supplied to the meshing point. If the gears are spur gears, the lubricating oil is discharged in the axial direction of the gears due to the pressure caused by the meshing of the gears. When lubricating oil is sprayed from the disengagement side, there is a gap that continues to the meshing point, but because it is blocked by the teeth, it is necessary to continue spraying with high oil pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-172708 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, in the case of high-speed rotating gears, when lubricating oil is supplied from the beginning of meshing, if a large amount of lubricating oil is supplied to the meshing point, the lubricating oil cannot be discharged in time, resulting in pumping of the lubricating oil, which may result in a loss of power transmission from the drive gear to the driven gear.

[0006] The present invention aims to provide a gear that can reduce power transmission loss due to pumping of lubricating oil when lubricating oil is supplied from the meshing start side during appropriate high-speed rotation, a reducer having such a gear, and a vehicle having such a reducer. [Means for solving the problem]

[0007] According to one aspect of the present invention, a gear that is used in mesh with another gear and to which lubricating oil is supplied from the meshing start side has a base portion having a root circle that defines a root circle diameter, a plurality of tooth portions arranged at a predetermined pitch circumferentially around the root circle of the base, and recesses that are each recessed relative to the root circle between adjacent tooth portions among the plurality of tooth portions and into which the lubricating oil is supplied from the meshing start side. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a gear that can reduce power transmission loss due to pumping of lubricating oil when lubricating oil is supplied from the meshing start side during appropriate high-speed rotation, a reducer having such a gear, and a vehicle having such a reducer. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic block diagram showing a vehicle according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the relationship between a drive source and a reducer. [Figure 3A] FIG. 3 is a schematic perspective view of the driven gear shown in FIG. 2. [Figure 3B] FIG. 3B is a schematic perspective view of the driven gear shown in FIG. 3A. [Figure 4A] FIG. 3C is a side view of the driven gear shown in FIGS. 3A and 3B. [Figure 4B] FIG. 4B is a cross-sectional view taken along line 4A-4A in FIG. 4A. [Figure 4C] FIG. 4C is a cross-sectional view taken along line 4C-4C in FIG. 4A. [Figure 5] 4D is a schematic diagram showing a method for manufacturing the driven gear shown in FIGS. 2 to 4C. FIG. [Figure 6]4D is a schematic diagram showing a method for manufacturing the driven gear shown in FIGS. 2 to 4C. FIG. [Figure 7A] 3 is a schematic diagram showing a state in which lubricating oil is supplied toward a meshing start position between the drive gear and the driven gear shown in FIG. 2. FIG. [Figure 7B] FIG. 7B is an enlarged view of the position indicated by the reference numeral 7B in FIG. 7A. [Figure 8] FIG. 10 is a schematic front view of a driven gear according to a modified example. [Figure 9] FIG. 10 is a schematic cross-sectional view of a driven gear according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] A preferred embodiment will be described with reference to the drawings.

[0011] (First embodiment) A vehicle 10 according to the first embodiment will be described with reference to FIGS. 1 to 7B.

[0012] FIG. 1 shows a schematic diagram of an electric vehicle as a vehicle 10 according to an embodiment.

[0013] As shown in FIG. 1, a vehicle 10 includes a battery 12, an inverter 14, a drive source (e.g., a motor) 16, and a reducer (a reducer for an electric vehicle) 18. The battery 12 is used as a DC power source. The inverter 14 converts the DC power from the battery 12 into AC power to drive the drive source 16, which is driven by AC power. That is, the battery 12 supplies power to drive the drive source 16. A reducer 18, which can be set to an appropriate reduction ratio, is connected to a rotating shaft 16a of the drive source 16. Then, power reduced to a predetermined reduction ratio by the reducer 18 is transmitted to wheels 22 via a drive shaft 20.

[0014] The vehicle 10 may be rear-wheel drive, front-wheel drive, or two-wheel drive.

[0015] FIG. 2 shows the drive source 16 and a part of the gear group 30 of the reducer 18.

[0016] 2, a drive gear (another gear) 32 is fixed to the rotary shaft 16a of the drive source 16. The drive gear 32 is meshed with a driven gear (gear) 34 that is rotatably supported on the rotary shaft 18a of the reducer 18.

[0017] For ease of explanation, the drive gear 32 and the driven gear 34 will be described as spur gears. The drive gear 32 and the driven gear 34 may be other types of gears, such as helical gears.

[0018] The sizes of the drive gear 32 and the driven gear 34 may differ in each drawing, but this is not intended.

[0019] The drive gear 32 has teeth 32a that mesh with teeth 44 of the driven gear 34, which will be described later.

[0020] Fig. 3A shows a schematic perspective view of the driven gear 34 shown in Fig. 2. Fig. 3B shows a schematic perspective view of the driven gear 34 shown in Fig. 3A.

[0021] Fig. 4A shows a side view of the driven gear 34 shown in Fig. 3A and Fig. 3B. Fig. 4B shows a cross-sectional view taken along line 4A-4A in Fig. 4A. Fig. 4C shows a cross-sectional view taken along line 4C-4C in Fig. 4A.

[0022] As shown in Figures 3A to 4C, the driven gear 34 has a base 42 having a root circle 41 that defines a root circle diameter df, and a plurality of teeth 44 arranged at a predetermined pitch around the root circle 41 of the base 42.

[0023] The base 42 has a fitting portion 43 into which a part of the rotation shaft 18a of the reducer 18 that is parallel to the rotation shaft 16a of the drive source 16 is fitted, for example.

[0024] The driven gear 34 has a lubricant oil discharge portion 46 for discharging lubricant oil when lubricant oil is supplied from the meshing start side between the driven gear 34 and the drive gear 32. The lubricant oil discharge portion 46 is provided on the base portion 42.

[0025] In this embodiment, the lubricant oil discharge portion 46 is provided in a concave shape on each of the root circles 41 between the tooth portions 44 that are adjacent to each other in the circumferential direction among the multiple tooth portions 44, and has a recess 52 for receiving lubricant oil supplied from the start of engagement side, and an annular groove 54 that connects the recess 52 to the fitting portion 43.

[0026] The annular groove 54 is formed in the base portion 42. The annular groove 54 is formed in an annular shape that connects the fitting portion 43 and the recessed portion 52. It is preferable that the central axis of the annular groove 54 coincides with the central axis of the driven gear 34.

[0027] In this embodiment, the lubricant oil discharge portion 46, that is, the recessed portion 52 and the annular groove 54, are preferably formed in the center of the driven gear 34 in the thickness direction.

[0028] The outer diameter of the annular groove 54 of the lubricant oil discharge portion 46 may be slightly larger, the same as, or smaller than the diameter of the root circle 41 of the base portion 42. On the other hand, the inner diameter of the annular groove 54 of the lubricant oil discharge portion 46 is preferably formed so as to pass through the fitting portion 43 in an annular shape. Therefore, the fitting portion 43 has an annular recessed groove 43a formed in a radially outward recessed shape and communicating with the annular groove 54.

[0029] A first manufacturing method for the driven gear 34 will be briefly described with reference to FIG.

[0030] As shown in FIG. 5(A), for example, a pair of disk-shaped members 62 and 64 having the same diameter are prepared, and an annular groove 66 is formed on one surface of each of the pair of disk-shaped members 62 and 64.

[0031] 5(B), the pair of disk-shaped members 62, 64 are brought into close contact with each other so that the annular grooves 66 face each other. Then, the pair of disk-shaped members 62, 64 are joined together using, for example, linear friction welding to form an integrated disk member 68. At this time, the pair of annular grooves 66 form an annular groove 54 at the center of the disk member 68 in the thickness direction.

[0032] 5(C), the teeth 44 and the root circle 41 are formed on the disk member 68. At this time, the recess 52 of the lubricant oil discharge portion 46 that communicates with the annular groove 54 of the lubricant oil discharge portion 46 is formed, and the driven gear 34 is obtained.

[0033] The second manufacturing method of the driven gear 34 will be briefly described with reference to FIG.

[0034] 6(A), a disk-shaped member 72 is prepared. Here, it is assumed that the fitting portion 43 has already been formed. Then, for example, while rotating the disk-shaped member 72 around its central axis, an annular groove 54 is formed radially outward in the disk-shaped member 72 using a tool T from the fitting portion 43 side of the disk-shaped member 72 where the rotation shaft 18a is fitted.

[0035] As shown in Fig. 6(B), the tool T is changed as necessary to enlarge the annular groove 54 until it reaches the desired size of the root circle 41. A laser cutter may be used as the tool T, and a disk-shaped member 72 shown in Fig. 6(B) may be obtained by laser processing.

[0036] Then, as shown in FIG. 6(C), the teeth portion 44 is formed to obtain the driven gear 34.

[0037] Thus, the driven gear 34 can be manufactured in a variety of ways.

[0038] In addition, if the outer diameter of the annular groove 54 of the lubricant oil discharge portion 46 is slightly larger than the diameter of the root circle 41 of the base 42, a recess 52 of the lubricant oil discharge portion 46 is automatically formed in the root circle 41 between circumferentially adjacent tooth portions 44 of the base 42 of the driven gear 34.

[0039] When the outer diameter of the annular groove 54 of the lubricant oil discharge portion 46 is the same as or smaller than the diameter of the root circle 41 of the base portion 42, the recess 52 is actively formed so that the recess 52 and the annular groove 54 are connected to each other.

[0040] The reducer 18 according to this embodiment has a lubricating oil supply unit (nozzle) 80 that supplies lubricating oil. The lubricating oil supply unit 80 is disposed so that the lubricating oil is supplied to the meshing start side.

[0041] The operation of the reducer 18 of the vehicle 10 according to this embodiment will be described below with reference to FIGS. 7A and 7B.

[0042] As shown in Figure 7A, when the drive source 16 is driven and the rotating shaft 16a is rotated while lubricating oil L is supplied from the lubricating oil supply unit 80 to the meshing start side of the drive gear 32 and the driven gear 34, the drive gear 32 rotates and the driven gear 34 rotates.

[0043] 7B , when lubricating oil L is supplied from the meshing start side of the drive gear 32 and the driven gear 34 as in this embodiment, lubricating oil L is supplied to the meshing point between the tooth portion 32a of the drive gear 32 and the tooth portion 44 of the driven gear 34. The meshing area between the drive gear 32 and the driven gear 34 becomes narrower as the drive gear 32 and the driven gear 34 mesh, and the pressure in the meshing area between the drive gear 32 and the driven gear 34 increases. Due to the pressure increased as the drive gear 32 and the driven gear 34 mesh, some of the lubricating oil L introduced into the meshing area between the drive gear 32 and the driven gear 34 passes through the gap between the tooth root between the tooth portion 44 of the driven gear 34 and the root circle 41 and is discharged in the axial direction of the driven gear 34.

[0044] In this embodiment, a portion of the lubricating oil L enters recesses 52 between circumferentially adjacent teeth 44 of the driven gear 34 in the meshing region between the drive gear 32 and the driven gear 34. Therefore, the recesses 52 in the meshing region between the drive gear 32 and the driven gear 34 can reduce the pressure generated in the meshing region between the drive gear 32 and the driven gear 34 so that it approaches the pressure at a position away from the meshing region, or can suppress an increase in such pressure.

[0045] As the rotational speeds of the drive gear 32 and the driven gear 34 increase, it becomes more difficult for the lubricating oil L to be discharged along the axial direction of the driven gear 34 in time for the pressure increase in the meshing region between the drive gear 32 and the driven gear 34, which increases the likelihood of a loss in power transmission from the drive gear 32 to the driven gear 34. However, in this embodiment, a recess 52 for receiving the lubricating oil L is formed in the root circle 41 of the driven gear 34, and the lubricating oil L is introduced into the recess 52 in the meshing region, thereby suppressing a pressure increase in the meshing region. Therefore, by using the driven gear 34 having the recess 52 according to this embodiment, it is possible to suppress pumping of the lubricating oil L in the meshing region between the drive gear 32 and the driven gear 34 and thereby suppress a loss in power transmission from the drive gear 32 to the driven gear 34.

[0046] In this embodiment, some of the lubricating oil L that has entered the recess 52 in the meshing region passes through the annular groove 54 that communicates with the recess 52 in the meshing region, and is discharged from the recess 52 where, for example, the teeth 32a of the drive gear 32 and the teeth 44 of the driven gear 34 are not meshed. Depending on the state of engagement, some of the lubricating oil L that has entered the annular groove 54 is discharged from between the recess 43a of the engagement portion 43, which is part of the annular groove 54, and the rotating shaft 18a of the reducer 18.

[0047] In this way, when lubricating oil L is supplied from the meshing start side, a portion of the lubricating oil L enters the recess 52 in the meshing area, and the driven gear 34 of this embodiment reduces the pressure in the meshing area between the drive gear 32 and the driven gear 34, or suppresses the increase in pressure, suppresses the pumping of the lubricating oil L, and reduces the power transmission loss from the drive gear 32 to the driven gear 34.

[0048] Furthermore, the driven gear 34 of this embodiment can ensure a discharge path for the lubricating oil L that has entered the recess 52 in the meshing area, thereby preventing the lubricating oil L from returning to the meshing area, suppressing pumping of the lubricating oil even when the lubricating oil L is supplied from the meshing start side, and reducing the power transmission loss from the drive gear 32 to the driven gear 34.

[0049] In this embodiment, the recesses 52 are provided on all of the root circles 41 between adjacent tooth portions 44. Therefore, regardless of which tooth portion 44 of the driven gear 34 is meshed with the tooth portion 32a of the drive gear 32, the driven gear 34 can ensure a discharge path for the lubricating oil L by the recesses 52 located in the meshing region. Therefore, even if the lubricating oil L is supplied from the meshing start side, pumping of the lubricating oil is suppressed, and the power transmission loss from the drive gear 32 to the driven gear 34 is reduced.

[0050] Furthermore, the driven gear 34 according to this embodiment has an annular groove 54 that communicates with all of the recesses 52, thereby ensuring a discharge path for the lubricating oil L in the rotational and radial directions of the driven gear 34. Therefore, the driven gear 34 according to this embodiment suppresses pumping of the lubricating oil L in the meshing region even when the lubricating oil L is supplied from the meshing start side, and the power transmission loss from the drive gear 32 to the driven gear 34 is reduced.

[0051] Therefore, according to this embodiment, when lubricating oil L is supplied from the start of engagement during appropriate high-speed rotation, it is possible to provide a gear 34 that can reduce power transmission loss due to pumping of lubricating oil L, a reducer 18 having the gear 34, and a vehicle 10 having the reducer 18.

[0052] In this embodiment, an example has been described in which the annular groove 54 communicates with the recess 52. For example, it is preferable to form the recess 52 with an appropriate volume, such as by increasing the size of the recess 52 on the root circle 41 in the thickness direction of the driven gear 34 or by making a larger area of ​​the root circle 41 between the teeth 44 the recess 52. In this case, if the amount of lubricating oil L that can be received in the recess 52 can be increased, the annular groove 54 for discharging the lubricating oil L may not be necessary. The lubricating oil L stored in the recess 52 in the meshing region can be discharged when the drive gear 32 and the driven gear 34 are no longer in mesh with each other.

[0053] In the present embodiment, an example has been described in which the driven gear 34 has the lubricant oil discharge portion 46. For example, it is also preferable that the drive gear (gear) 32 also has the recess 52 (and annular groove 54) of the lubricant oil discharge portion 46 similar to the recess 52 (and annular groove 54) of the lubricant oil discharge portion 46 of the driven gear (gear) 34. Alternatively, there may be a case in which the drive gear (gear) 32 has the recess 52 (and annular groove 54) of the lubricant oil discharge portion 46, but the driven gear (another gear) 34 does not have the lubricant oil discharge portion 46. In this case, when the drive gear 32 supplies the lubricant oil L from the meshing start side in the meshing region between the drive gear 32 and the driven gear 34, for example, during appropriate high-speed rotation, it is possible to reduce power transmission loss due to pumping of the lubricant oil L. That is, for example, when two gears 32, 34 mesh with each other, it is preferable that at least one of the gears 32, 34 has the recess 52 (and the annular groove 54) of the lubricant discharge portion 46.

[0054] (Variation) Fig. 8 shows a cross-sectional view of a driven gear (gear) 34 according to a modified example of the first embodiment. The cross-section shown in Fig. 8 corresponds to the cross-section of the driven gear (gear) 34 shown in Fig. 4C.

[0055] In this modification, a plurality of lubricant oil discharge portions 46 are arranged side by side in the thickness direction of the base portion 42.

[0056] For example, depending on the thickness of the driven gear 34, the expected amount of lubricating oil L, etc., the lubricating oil discharge portion 46 may be formed in this manner.

[0057] 8 of this modified example illustrates an example in which two lubricant oil discharge portions 46 are arranged side by side in the thickness direction of the base 42. Although not illustrated, it is of course also preferable to arrange three or more lubricant oil discharge portions 46 side by side in the thickness direction of the base 42.

[0058] As mentioned above, it is also preferable that the drive gear 32 has a lubricant discharge portion 46 having the structure shown in FIG.

[0059] (Second embodiment) Next, a driven gear 34 according to a second embodiment will be described with reference to Fig. 9. This embodiment is a modified example of the first embodiment including modifications, and the same components as those described in the first embodiment or components having the same functions are denoted by the same reference numerals as much as possible, and detailed descriptions thereof will be omitted.

[0060] As shown in FIG. 9, in this embodiment, an example in which the driven gear 34 is formed as a spur gear will also be described.

[0061] The base 42 is provided with a lubricant discharge portion 46 .

[0062] In this embodiment, the lubricant oil discharge portion 46 is provided in a concave shape on the root circle 41 between circumferentially adjacent tooth portions 44 among the plurality of tooth portions 44, and has a recess 52 that serves as an inlet for lubricant oil supplied from the meshing start side, and a communication passage 56 that connects the circumferentially adjacent recesses 52 within the base 42. The communication passage 56 is provided on the central axis side of the driven gear 34 with respect to the tooth portions 44.

[0063] In this embodiment, the communication passages 56 are formed below the tooth portions 44 at every other tooth portion 44 in the circumferential direction. Therefore, at least some of the recesses 52 communicate with each other through the communication passages 56. The communication passages 56 are alternately formed in positions where they are formed directly below the tooth portions 44 and positions where they are not formed directly below the tooth portions 44.

[0064] The driven gear 34 having the communication passages 56 connecting the recesses 52 together is manufactured, for example, in the same manner as the first manufacturing method described above.

[0065] The operation of the reducer 18 of the vehicle 10 according to this embodiment will be described below.

[0066] The driven gear 34 according to this embodiment is used in place of the driven gear 34 shown in FIG. 7A.

[0067] When lubricating oil L is supplied from the meshing start side of the drive gear 32 and the driven gear 34, the lubricating oil L is supplied to the meshing point between the tooth portion 32a of the drive gear 32 and the tooth portion 44 of the driven gear 34. The space in the meshing region between the drive gear 32 and the driven gear 34 becomes narrower as the drive gear 32 and the driven gear 34 mesh more, and the pressure in the meshing region between the drive gear 32 and the driven gear 34 increases. Some of the lubricating oil L introduced into the meshing region between the drive gear 32 and the driven gear 34 is discharged in the axial direction of the driven gear 34 through the gap between the root of the tooth between the tooth portion 44 of the driven gear 34 and the root circle 41 due to the pressure that increases as the drive gear 32 and the driven gear 34 mesh more.

[0068] In this embodiment, a portion of the lubricating oil L enters the recesses 52 between the circumferentially adjacent teeth 44 of the driven gear 34. As a result, the pressure generated in the meshing region between the drive gear 32 and the driven gear 34 can be reduced to approach the pressure at a position away from the meshing region, or an increase in such pressure can be suppressed.

[0069] As the rotational speeds of the drive gear 32 and the driven gear 34 increase, it becomes more difficult for the lubricating oil L to be discharged along the axial direction of the driven gear 34 in time for the pressure increase in the meshing region between the drive gear 32 and the driven gear 34, which increases the likelihood of power transmission loss. However, in this embodiment, a recess 52 for receiving the lubricating oil L is formed in the root circle 41 of the driven gear 34, and the lubricating oil L is received in the recess 52 in the meshing region between the drive gear 32 and the driven gear 34, thereby suppressing the pressure increase in the meshing region. Therefore, by using the driven gear 34 having the recess 52 according to this embodiment, it is possible to suppress the pumping of the lubricating oil L and suppress the power transmission loss from the drive gear 32 to the driven gear 34.

[0070] 7A, the meshing pressure is lower upstream of the meshing region between the drive gear 32 and the driven gear 34 than in the current meshing region, and the meshing pressure is not higher downstream of the meshing region than in the current meshing region. In other words, the pressure of the lubricating oil L in the meshing region immediately preceding the current meshing region and the meshing region immediately following the current meshing region, both of which are adjacent to the current meshing region, is lower than the pressure of the lubricating oil L in the current meshing region.

[0071] In this embodiment, due to the pressure in the meshing area, a portion of the lubricating oil L that has entered the recess 52 passes through the communication passage 56 that communicates with the recess 52, and is discharged from the recess 52 of the adjacent, immediately preceding meshing area or the immediately succeeding meshing area, which has a lower pressure than the pressure due to the current meshing area.

[0072] In this way, when lubricating oil L is supplied from the meshing start side, a portion of the lubricating oil L enters the recess 52 in the meshing area, and the driven gear 34 of this embodiment reduces the pressure in the meshing area between the drive gear 32 and the driven gear 34, or suppresses the increase in pressure, suppresses the pumping of the lubricating oil L, and reduces the power transmission loss from the drive gear 32 to the driven gear 34.

[0073] Furthermore, the driven gear 34 of this embodiment can ensure a discharge path for the lubricating oil L that has entered the recess 52 in the meshing area, thereby preventing the lubricating oil L from returning to the meshing area, suppressing pumping of the lubricating oil even when the lubricating oil L is supplied from the meshing start side, and reducing the power transmission loss from the drive gear 32 to the driven gear 34.

[0074] In this embodiment, the recesses 52 and the communication passages 56 are provided in all spaces between adjacent tooth portions 44 on the root circle 41. Therefore, regardless of which tooth portion 44 of the driven gear 34 is meshed with the tooth portion 32a of the drive gear 32, the recesses 52 of the driven gear 34 can ensure a discharge path for the lubricating oil L. Therefore, even if the lubricating oil L is supplied from the meshing start side, pumping of the lubricating oil is suppressed, and power transmission loss from the drive gear 32 to the driven gear 34 is reduced.

[0075] Furthermore, the driven gear 34 of this embodiment has an annular groove 54 that communicates with all of the recesses 52, which ensures a discharge path for the lubricating oil L in the rotational and radial directions of the driven gear 34. Therefore, even if the lubricating oil L is supplied from the meshing start side, pumping of the lubricating oil is suppressed, and the power transmission loss from the drive gear 32 to the driven gear 34 is reduced.

[0076] Therefore, according to this embodiment, when lubricating oil L is supplied from the start of engagement during appropriate high-speed rotation, it is possible to provide a gear 34 that can reduce power transmission loss due to pumping of lubricating oil L, a reducer 18 having the gear 34, and a vehicle 10 having the reducer 18.

[0077] The driven gear 34 according to the present embodiment has been described as having an even number of tooth portions 44, with the communicating passages 56 provided immediately below every other tooth portion 44 in the circumferential direction. In the case of an odd number of tooth portions 44, adjacent recesses 52 may be sequentially connected to each other in the circumferential direction by the communicating passages 56, that is, communicating passages 56 may be formed below all of the tooth portions 44, thereby ensuring a discharge path for the lubricating oil L. Alternatively, one or more of the communicating passages 56 adjacent to each other in the circumferential direction may be connected to each other.

[0078] As mentioned above, it is also preferable that the drive gear 32 has a lubricant discharge portion 46 having the structure shown in FIG.

[0079] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0080] 10...vehicle, 12...battery, 14...inverter, 16...drive source, 16a...rotating shaft, 18...reduction gear, 18a...rotating shaft, 20...drive shaft, 22...wheel, 30...gear group, 32...drive gear, 32a...tooth portion, 34...driven gear, 41...root circle, 42...base, 43...fitting portion, 43a...groove, 44...tooth portion, 46...lubricant discharge portion, 52...recess, 54...annular groove, 62, 64...disc-shaped member, 66...annular groove, 72...disc-shaped member, 80...lubricant supply portion (nozzle).

Claims

1. A gear that is used in mesh with another gear and to which lubricating oil is supplied from the meshing start side, a base having a root circle defining a root circle diameter; a plurality of teeth provided at a predetermined pitch in the circumferential direction of the root circle of the base; a recessed portion provided between adjacent tooth portions among the plurality of tooth portions and having a recessed shape with respect to the tooth root circle, into which the lubricating oil is introduced from the meshing start side; A gear having a

2. the recesses are provided on all the root circles between the adjacent teeth, 2. The gear according to claim 1.

3. At least some of the recesses communicate with each other. The gear according to claim 1 or 2.

4. The recess communicates with an annular groove formed in the base around the central axis of the base. The gear according to claim 1 or 2.

5. A plurality of the recesses are arranged side by side in the thickness direction of the base. The gear according to claim 1 or 2.

6. the other gear driven by a drive source; the gear according to claim 1 or 2, which is meshed with the other gear; a lubricant oil supply unit that supplies the lubricant oil from the meshing start side between the other gear and the gear; A reducer having

7. The reducer according to claim 6; the drive source that drives the other gear; a battery that supplies power to drive the drive source; A vehicle having:

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