motor

Abstract

To appropriately adjust a supply distribution amount of a coolant to a plurality of components of a motor according to rotation speed of the motor by using a cooling structure of a simple configuration.SOLUTION: A motor includes: a rotor having a shaft; a stator provided around the rotor; a main flow path formed to extend in the axial direction inside the shaft and configured to allow a coolant to flow in one direction in the axial direction; a first branch flow path that is formed so as to extend in a direction intersecting the axial direction inside the shaft and branches from the main flow path; a first spiral structure that is provided on one side in the axial direction of the first branch flow path of an inner peripheral surface of the main flow path; and a second spiral structure provided on the other side in the axial direction of the first branch flow path of the inner peripheral surface of the main flow path so as to be separated from the first spiral structure. A spiral direction of the first spiral structure is opposite to that of the second spiral structure.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] Conventionally, in a rotating electric machine such as a motor for a vehicle, cooling of a stator and a rotor is performed by cooling oil. By changing the temperature of a permanent magnet attached to a rotor by cooling of the cooling oil according to the rotational speed of the rotating electric machine, the output torque characteristics of the rotating electric machine can be improved.

[0003] For example, Patent Document 1 discloses providing supply destination changing means for changing the supply destination of cooling oil to a stator winding or a permanent magnet of a rotor according to the rotational speed of the rotating electric machine. By changing the supply destination of the cooling oil, the temperature of the permanent magnet attached to the rotor can be changed according to the rotational speed of the rotating electric machine.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a motor for a vehicle, for example, at low rotation (high torque) of the motor, the stator coil becomes high temperature, while at high rotation (low torque), the rotor magnet becomes high temperature. Therefore, it is preferable to appropriately switch the supply and distribution amount of the coolant to a plurality of parts to be cooled according to the rotational speed of the motor, and supply a large amount of the coolant to the high-temperature parts for cooling.

[0006] However, the rotating electric machine described in Patent Document 1 has a supply destination changing mechanism for switching the supply destination of the cooling oil, which is provided on the cylindrical member of the rotor. This has the problem of increasing the number of parts in the rotating electric machine and making the rotating electric machine larger.

[0007] Therefore, the present invention aims to provide a motor that uses a simple cooling structure and can appropriately adjust the amount of coolant supplied to multiple components of the motor according to the motor's rotational speed. [Means for solving the problem]

[0008] To solve the above problems, the motor of the present invention is: A rotor having a shaft, A stator is provided around the rotor, A main channel is formed inside the shaft so as to extend axially, and configured so that the coolant flows in one direction in the axial direction, A first branch channel is formed inside the shaft so as to extend in a direction intersecting the axial direction and branching off from the main channel, A first helical structure is provided on the inner circumferential surface of the main channel on one side in the axial direction of the first branch channel, A second helical structure is provided on the inner circumferential surface of the main flow channel, on the side in the axial direction opposite to the first branch flow channel, and is spaced apart from the first helical structure. Equipped with, The first helical structure is provided on the inner circumferential surface of the main flow channel, on the upstream side of the coolant flow than the first branch flow channel. The second helical structure is provided on the inner circumferential surface of the main flow channel, downstream of the first branch flow channel in the flow of the coolant. The helical direction of the first helical structure is opposite to the helical direction of the second helical structure. the law of nature , The spiral direction of the first helical structure is the positive direction, which is aligned with the rotational direction of the shaft. The helical direction of the second helical structure is opposite to the forward direction. The first branch channel is a channel for supplying the coolant to the stator. . [Effects of the Invention]

[0009] According to the present invention, it is possible to appropriately adjust the amount of coolant supplied to multiple components of a motor according to the motor's rotational speed using a simple cooling structure. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram showing the configuration of the vehicle. [Figure 2] Figure 2 is a schematic cross-sectional view showing the configuration of the cooling mechanism of the motor according to this embodiment at low rotation speeds. [Figure 3] Figure 3 is a schematic cross-sectional view showing the configuration of the cooling mechanism of the motor according to this embodiment during high-speed rotation. [Figure 4] Figure 4 is a schematic cross-sectional view showing the configuration of the cooling mechanism of the motor according to this modified example at low rotation speeds. [Figure 5] Figure 5 is a schematic cross-sectional view showing the configuration of the cooling mechanism of the motor according to this modified example at high rotational speeds. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described in detail below with reference to the attached drawings. The specific dimensions, materials, numerical values, etc., shown in these embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0012] Figure 1 is a schematic diagram showing the configuration of the vehicle 100 according to this embodiment. In this embodiment, the vehicle 100 is an electric vehicle equipped with a motor as a drive source. However, it is not limited to this, and the vehicle 100 may be a hybrid vehicle equipped with an engine and a motor as power sources. The vehicle 100 of this embodiment is capable of both 4WD (four-wheel drive) driving, where both the front and rear wheels are driven, and 2WD (two-wheel drive) driving, where only the front wheels are driven.

[0013] Vehicle 100 includes a motor 110, an inverter 112, a battery 114, a transmission 116, an electronic control unit (hereinafter simply referred to as ECU) 118, a propeller shaft 120, a front differential gear 122, a front drive shaft 124, front wheels 126, an electronically controlled coupling 128, a rear differential gear 130, a rear drive shaft 132, rear wheels 134, a transmission case 136, and a cooling device 200.

[0014] The motor 110 obtains driving force by the electric power supplied from the battery 114 via the inverter 112, and transmits the obtained driving force to the transmission 116. Further, the motor 110 also functions as a generator at the timing when it is not receiving power supply. The electric power generated by the motor 110 is stored in the battery 114 via the inverter 112. Also, the inverter 112 is connected to the ECU 118, and the supply power, that is, the driving force of the motor 110 is adjusted based on the control command of the ECU 118.

[0015] The driving force output from the motor 110 is transmitted to the propeller shaft 120 after the torque, rotational speed, and rotational direction are adjusted by the transmission 116, and further transmitted to the front wheels 126 via the front differential gear 122 and the front drive shaft 124.

[0016] Also, during 4WD driving, the driving force output from the transmission 116 is also transmitted to the rear wheels 134 via the electronically controlled coupling 128, the rear differential gear 130, and the rear drive shaft 132. Here, the front wheels 126 obtain the driving force directly from the transmission 116, and the rear wheels 134 obtain the driving force via the electronically controlled coupling 128. However, it is also possible to transmit the driving force directly from the transmission 116 to the rear wheels 134 and transmit the driving force to the front wheels 126 via the electronically controlled coupling 128.

[0017] The transmission case 136 houses the motor 110, the transmission 116, and the cooling device 200. The transmission case 136 has an oil pan (not shown), which stores transmission oil (hereinafter simply referred to as oil) for cooling and lubricating the components inside the transmission case 136.

[0018] The cooling system 200 includes a cooling mechanism 210 and an electric oil pump (hereinafter simply referred to as EOP) 250. The cooling mechanism 210 in this embodiment is installed inside the motor 110. In other words, the motor 110 is equipped with the cooling mechanism 210 of this embodiment. The EOP 250 supplies oil (coolant) stored in the oil pan of the transmission case 136 to the cooling mechanism 210.

[0019] The EOP250 is connected to the ECU118 and adjusts the oil volume and pressure supplied to the cooling mechanism 210 based on control commands from the ECU118. The ECU118 controls the EOP250 so that, for example, the oil volume and pressure increase as the rotational speed of the motor 110 increases.

[0020] Figure 2 is a schematic diagram showing the configuration of the cooling mechanism 210 of the motor 110 at low rotational speed according to this embodiment. As shown in Figure 2, the motor 110 has a stator 140 and a rotor 160.

[0021] The stator 140 is positioned around the rotor 160. The stator 140 comprises a stator core 142 and a coil 144. When power is supplied to the coil 144, the stator 140 generates a magnetic field that rotates the rotor 160.

[0022] The stator core 142 is formed in a cylindrical shape and is located radially outward of the rotor 160. The central axis of the stator core 142 is positioned at the same location as the rotational axis of the rotor 160. Here, "equal" includes cases where they are perfectly equal and cases where they deviate from the perfectly equal case within the range of tolerances (machining accuracy, assembly errors, etc.). Hereafter, "equal" or "same" includes cases where they are perfectly equal or the same and cases where they deviate from the perfectly equal or the same case within the range of tolerances (machining accuracy, assembly errors, etc.).

[0023] Teeth (not shown) are arranged at equal intervals in the circumferential direction on the inner surface of the stator core 142. A coil 144 is wound around several of these teeth. A portion of the coil 144 wound around the teeth protrudes from both ends of the stator core 142 in the direction of the central axis of the stator core 142. Hereinafter, the portion of the coil 144 that protrudes from both ends of the stator core 142 is referred to as the coil end 144a (first object to be cooled).

[0024] The rotor 160 comprises a shaft 162 and a rotor core 164. The shaft 162 has a holding portion 162a for holding the rotor core 164. The rotor core 164 is formed in a cylindrical shape, and its inner diameter side is held by the holding portion 162a of the shaft 162. The rotor core 164 has a magnet 164a (second object to be cooled) inside. The magnet 164a is, for example, a permanent magnet.

[0025] The rotor core 164 faces the stator core 142 in the radial direction. The rotor core 164 is rotated by the magnetic field generated by the coils 144 of the stator 140, and the shaft 162 rotates integrally with the rotor core 164.

[0026] The cooling mechanism 210 is provided on the shaft 162 of the rotor 160 and is a mechanism that supplies oil supplied from the EOP 250 to at least one of the coil end 144a and magnet 164a, which are to be cooled, thereby providing cooling.

[0027] When the motor 110 is operating at high torque, i.e., at low rotational speeds, a large current flows through the coil 144, causing the coil 144 to become hot. Therefore, it is necessary to prioritize cooling the coil 144 over the magnet 164a. On the other hand, when the motor 110 is operating at high rotational speeds, the temperature rise of the magnet 164a increases significantly with increasing rotational speed. Therefore, it is necessary to prioritize cooling the magnet 164a over the coil 144.

[0028] Therefore, the cooling mechanism 210 of this embodiment is configured to appropriately adjust the amount of oil supplied to the coil ends 144a and magnets 164a, which are multiple components of the motor 110, according to the rotational speed of the motor 110. In other words, the cooling mechanism 210 of this embodiment is configured to change the destination of the oil supply according to the rotational speed of the motor 110. The cooling mechanism 210 has a main flow path 212, a first branch flow path 214, a second branch flow path 216, a first helical structure 218, and a second helical structure 220.

[0029] The main flow path 212 is formed in the shaft 162. An opening O1 is formed at one axial end of the shaft 162, and an opening O2 is formed at the other end. The main flow path 212 is formed to extend axially from opening O1 to opening O2 inside the shaft 162. The main flow path 212 is a through hole that penetrates the shaft 162 axially from opening O1 to opening O2.

[0030] Oil supplied from the EOP250 is supplied to the opening O1 of the main flow path 212. The main flow path 212 allows the oil supplied from the EOP250 to flow from opening O1 to opening O2. In this way, the main flow path 212 is configured so that the oil supplied from the EOP250 flows in one direction axially.

[0031] The first branch passage 214 is a branch passage that branches off from the main passage 212. A portion of the oil flowing through the main passage 212 flows into the first branch passage 214. The first branch passage 214 is formed to extend in a direction intersecting the axial direction inside the shaft 162. Specifically, the first branch passage 214 is formed to extend in the radial direction of the shaft 162 and is formed by a through hole that penetrates the shaft 162 radially.

[0032] The first branch passage 214 is formed in the portion of the shaft 162 that is radially opposite to the coil end 144a of the stator 140. The oil flowing through the first branch passage 214 is injected from the outer surface of the shaft 162 toward the coil end 144a of the stator 140. The coil end 144a is cooled by the oil coming into contact with it. Thus, the first branch passage 214 is a passage for supplying oil to the coil end 144a of the stator 140.

[0033] The first branch channel 214 is located upstream of the oil flow in the main channel 212 compared to the second branch channel 216. The first branch channel 214 is located downstream of the oil flow in the main channel 212 compared to the first helical structure 218. The first branch channel 214 is located upstream of the oil flow in the main channel 212 compared to the second helical structure 220. In other words, the first branch channel 214 is located between the first helical structure 218 and the second helical structure 220.

[0034] The second branch passage 216 is a branch passage that branches off from the main passage 212. A portion of the oil flowing through the main passage 212 flows into the second branch passage 216. The second branch passage 216 is formed to extend in a direction that intersects the axial direction within the shaft 162. Specifically, the second branch passage 216 is formed to extend in the radial direction of the shaft 162 and is formed by a through hole that penetrates the shaft 162 radially.

[0035] The second branch channel 216 is formed in the portion of the shaft 162 that is radially opposite to the rotor core 164. The oil flowing through the second branch channel 216 is injected from the outer surface of the shaft 162 toward the inner surface of the rotor core 164.

[0036] Here, the rotor core 164 has a magnet cooling channel 166 that opens in a portion radially opposite to the second branch channel 216. The magnet cooling channel 166 has a supply channel 166a that extends radially from the inner circumferential surface of the rotor core 164 to the magnet 164a inside the rotor core 164, and a discharge channel 166b that extends axially along the inner circumferential surface of the magnet 164a.

[0037] The oil injected from the second branch channel 216 flows into the supply channel 166a of the magnet cooling channel 166, and is discharged to the outside from the side of the rotor core 164 through the supply channel 166a and the discharge channel 166b. As the oil flows through the discharge channel 166b, the magnets 164a inside the rotor core 164 are cooled. Thus, the second branch channel 216 is a channel for supplying oil to the magnets 164a inside the rotor core 164.

[0038] The second branch channel 216 is located downstream of the oil flow in the main channel 212 compared to the first branch channel 214. The second branch channel 216 is located downstream of the oil flow in the main channel 212 compared to the first helical structure 218 and the second helical structure 220.

[0039] The first helical structure 218 is composed of projections that protrude from the inner circumferential surface of the shaft 162 into the main flow path 212. The projections are formed, for example, in a helical or propeller shape. The helical shape is, for example, a three-dimensional curve that rises in a direction perpendicular to the plane of rotation while rotating. The propeller shape is, for example, a wing shape such as multiple blades provided on an aircraft to generate lift. However, the first helical structure 218 may also be composed of grooves that are recessed from the inner circumferential surface of the shaft 162 toward the outer circumferential surface. The grooves are formed, for example, in a helical or propeller shape.

[0040] The first helical structure 218 is located on the inner surface of the main flow path 212, on the side of the opening O1 that is closer to the first branch flow path 214. In other words, the first helical structure 218 is located on the inner surface of the main flow path 212, on the upstream side of the oil flow that is closer to the first branch flow path 214. To put it another way, the first helical structure 218 is located on the inner surface of the main flow path 212, on one side of the axial direction that is closer to the first branch flow path 214.

[0041] The spiral direction of the first helical structure 218 is the same as the rotation direction of the shaft 162 (hereinafter referred to as the positive direction). In other words, the spiral direction of the first helical structure 218 is the positive direction, which is aligned with the rotation direction of the shaft 162. The spiral direction refers to the winding direction of the helical structure (for example, clockwise or counterclockwise) when viewed from the upstream side of the coolant flow. For example, when viewed from the upstream side of the coolant flow, if the rotation direction of the shaft 162 is clockwise, then the spiral direction of the first helical structure 218 is also clockwise. Figure 2 shows the shaft 162 rotating clockwise when viewed from the upstream side of the coolant flow.

[0042] The second helical structure 220 is composed of projections that protrude from the inner circumferential surface of the shaft 162 into the main flow path 212. The projections are formed, for example, in a helical or propeller shape. However, it is not limited to this, and the second helical structure 220 may also be composed of grooves that are recessed from the inner circumferential surface of the shaft 162 toward the outer circumferential surface. The grooves are formed, for example, in a helical or propeller shape.

[0043] The second helical structure 220 is located on the inner circumferential surface of the main flow path 212, on the side of the opening O2 that is closer to the first branch flow path 214. In other words, the second helical structure 220 is located on the inner circumferential surface of the main flow path 212, downstream of the first branch flow path 214. To put it another way, the second helical structure 220 is located on the inner circumferential surface of the main flow path 212, on the other side of the axial direction that is closer to the first branch flow path 214.

[0044] The second helical structure 220 is provided at an axial distance from the first helical structure 218. The second helical structure 220 is provided on the inner circumferential surface of the main flow path 212, upstream of the second branch flow path 216 in the oil flow.

[0045] The spiral direction of the second helical structure 220 is opposite to the rotation direction of the shaft 162. In other words, the spiral direction of the second helical structure 220 is opposite to the forward direction. For example, when viewed from the upstream side of the coolant flow, if the rotation direction of the shaft 162 is clockwise, the spiral direction of the second helical structure 220 is counterclockwise. Thus, the spiral direction of the first helical structure 218 is opposite to the spiral direction of the second helical structure 220.

[0046] The oil introduced into the main channel 212 from the opening O1 passes through the first helical structure 218 as it flows through the main channel 212. The flow velocity of the oil flowing through the main channel 212 is reduced as it collides with the protrusions of the first helical structure 218 as it passes through it.

[0047] Here, since the first helical structure 218 has a forward-facing helical shape that matches the rotational direction of the shaft 162, the lower the rotational speed of the shaft 162, the more likely the oil is to collide with the protrusions of the first helical structure 218. As a result, it becomes more difficult for the oil to flow through the first helical structure 218. In other words, the lower the rotational speed of the shaft 162, the greater the reduction in flow velocity before and after the oil passes through the first helical structure 218.

[0048] According to Bernoulli's theorem and the continuity equation, the greater the reduction in flow velocity, the higher the pressure of the oil after passing through the first helical structure 218, making it easier for oil to be injected from the first branched passage 214 formed downstream of the first helical structure 218. As a result, the amount of oil injected from the first branched passage 214 is greater than that from the second branched passage 216.

[0049] Thus, at low rotational speeds of the motor 110, most of the oil circulating in the main passage 212 is injected from the first branch passage 214, and almost no oil is injected from the second branch passage 216. Therefore, the cooling mechanism 210 of this embodiment can prioritize cooling the coil end 144a over the magnet 164a at low rotational speeds of the motor 110.

[0050] Figure 3 is a schematic diagram showing the configuration of the cooling mechanism 210 of the motor 110 according to this embodiment at high rotation speed. As shown in Figure 3, the oil introduced into the main flow path 212 from the opening O1 passes through the first helical structure 218 in the process of flowing through the main flow path 212. The flow velocity of the oil flowing through the main flow path 212 is reduced as it collides with the protrusions of the first helical structure 218 in the process of passing through the first helical structure 218.

[0051] Here, since the first helical structure 218 has a forward-facing helical shape that matches the rotational direction of the shaft 162, the higher the rotational speed of the shaft 162, the less likely the oil is to collide with the protrusions of the first helical structure 218. As a result, the oil flows more easily within the first helical structure 218. In other words, the higher the rotational speed of the shaft 162, the smaller the reduction in flow velocity before and after the oil passes through the first helical structure 218.

[0052] According to Bernoulli's theorem and the equation of continuity, the smaller the reduction in flow velocity, the lower the pressure of the oil after passing through the first helical structure 218, making it more difficult for oil to be injected from the first branched flow path 214 formed downstream of the first helical structure 218.

[0053] Meanwhile, oil that passes through the first helical structure 218 and is not injected from the first branched flow path 214 passes through the second helical structure 220. The flow velocity of the oil circulating in the main flow path 212 is reduced as it passes through the second helical structure 220 by colliding with the protrusions of the second helical structure 220.

[0054] Here, the second helical structure 220 has a helical shape that is opposite to the direction of rotation of the shaft 162. Therefore, in the second helical structure 220, unlike the first helical structure 218, the higher the rotational speed of the shaft 162, the more likely the oil is to collide with the protrusions of the second helical structure 220, making it more difficult for the oil to flow through the second helical structure 220. In other words, the higher the rotational speed of the shaft 162, the greater the reduction in flow velocity of the oil before and after passing through the second helical structure 220.

[0055] According to Bernoulli's theorem and the continuity equation, the greater the reduction in flow velocity, the higher the pressure of the oil after passing through the second helical structure 220, making it easier for oil to be injected from the second branched passage 216 formed downstream of the second helical structure 220. As a result, the amount of oil injected from the second branched passage 216 is greater than that from the first branched passage 214.

[0056] Thus, when the motor 110 is rotating at high speed, most of the oil circulating in the main passage 212 is injected from the second branch passage 216, and almost no oil is injected from the first branch passage 214. Therefore, the cooling mechanism 210 of this embodiment can prioritize cooling the magnet 164a over the coil end 144a when the motor 110 is rotating at high speed.

[0057] As described above, in the cooling mechanism 210 of this embodiment, the spiral direction of the first helical structure 218 is in the positive direction, which is aligned with the rotation direction of the shaft 162. Therefore, as the rotational speed of the rotor 160 increases, the amount of deceleration of the oil flow by the first helical structure 218 decreases. On the other hand, the spiral direction of the second helical structure 220 is in the opposite direction to the rotation direction of the shaft 162. Therefore, as the rotational speed of the rotor 160 increases, the amount of deceleration of the oil by the second helical structure 220 increases.

[0058] In this way, by changing the axial flow velocity of the oil circulating inside the shaft 162 according to the rotational speed of the motor 110, the destination of the oil can be changed to the coil end 144a or the magnet 164a. The cooling mechanism 210 of this embodiment can be formed by machining the inside of the shaft 162, without increasing the size of the shaft 162 or requiring any additional parts. Therefore, using a cooling structure with a simple configuration, the amount of coolant supplied to multiple parts of the motor 110 can be appropriately adjusted according to the rotational speed of the motor 110.

[0059] Furthermore, at least one of the pitch number, blade angle, and axial length of the first helical structure 218 is set so that the amount of deceleration of the oil flow by the first helical structure 218 is a desired amount. Similarly, at least one of the pitch number, blade angle, and axial length of the second helical structure 220 is set so that the amount of deceleration of the oil flow by the second helical structure 220 is a desired amount.

[0060] Figure 4 is a schematic diagram showing the configuration of the cooling mechanism 310 according to this modified example. Components that are substantially the same as those in the cooling mechanism 210 of the above embodiment are denoted by the same reference numerals and their descriptions are omitted. In the above embodiment, oil flowed into the main passage 212 from opening O1, whereas in this modified example, the oil flows into the main passage 212 from opening O2, which is different from the above embodiment. Also, the positions of the first branch passage 314 and the second branch passage 316 within the shaft 162 in this modified example are different from those in the above embodiment. Furthermore, the positions of the first helical structure 318 and the second helical structure 320 within the shaft 162 are different from those in the above embodiment. Figure 4 shows the shaft 162 rotating in the same direction as in Figure 2.

[0061] As shown in Figure 4, the first branch passage 314 is a branch passage that branches off from the main passage 212. A portion of the oil flowing through the main passage 212 flows into the first branch passage 314. The first branch passage 314 is formed to extend in a direction intersecting the axial direction inside the shaft 162. Specifically, the first branch passage 314 is formed to extend in the radial direction of the shaft 162 and is formed by a through hole that penetrates the shaft 162 radially.

[0062] The first branch channel 314 is formed in the part of the shaft 162 that is radially opposite to the magnet cooling channel 166 of the rotor core 164. The oil flowing through the first branch channel 314 is injected from the outer surface of the shaft 162 toward the magnet cooling channel 166 of the rotor core 164. In this way, the first branch channel 314 is a channel for supplying oil to the magnets 164a of the rotor core 164.

[0063] The first branch channel 314 is located upstream of the oil flow in the main channel 212 compared to the second branch channel 316. The first branch channel 314 is located downstream of the oil flow in the main channel 212 compared to the first helical structure 318. The first branch channel 314 is located upstream of the oil flow in the main channel 212 compared to the second helical structure 320. In other words, the first branch channel 314 is located between the first helical structure 318 and the second helical structure 320.

[0064] The second branch passage 316 is a branch passage that branches off from the main passage 212. A portion of the oil flowing through the main passage 212 flows into the second branch passage 316. The second branch passage 316 is formed to extend in a direction intersecting the axial direction within the shaft 162. Specifically, the second branch passage 316 is formed to extend in the radial direction of the shaft 162 and is formed by a through hole that penetrates the shaft 162 radially.

[0065] The second branch passage 316 is formed in the portion of the shaft 162 that is radially opposite to the coil end 144a of the stator 140. The oil flowing through the second branch passage 316 is injected from the outer surface of the shaft 162 toward the coil end 144a. The coil end 144a is cooled when the oil comes into contact with it. In this way, the second branch passage 316 is a passage for supplying oil to the coil end 144a.

[0066] The second branch channel 316 is located downstream of the oil flow in the main channel 212 compared to the first branch channel 314. The second branch channel 316 is located downstream of the oil flow in the main channel 212 compared to the first helical structure 318 and the second helical structure 320.

[0067] The first helical structure 318 is composed of projections that protrude from the inner circumferential surface of the shaft 162 into the main flow path 212. The projections are formed, for example, in a helical or propeller shape. However, it is not limited to this, and the first helical structure 318 may also be composed of grooves that are recessed from the inner circumferential surface of the shaft 162 toward the outer circumferential surface. The grooves are formed, for example, in a helical or propeller shape.

[0068] The first helical structure 318 is located on the inner circumferential surface of the main channel 212, on the side of the opening O2 that is closer to the first branch channel 314. In other words, the first helical structure 318 is located on the inner circumferential surface of the main channel 212, on the side of the first branch channel 314 that is further upstream. To put it another way, the first helical structure 318 is located on the inner circumferential surface of the main channel 212, on one side of the axial direction that is closer to the first branch channel 314.

[0069] The spiral direction of the first helical structure 318 is opposite to the rotational direction of the shaft 162. In other words, the spiral direction of the first helical structure 318 is opposite to the forward direction of rotation of the shaft 162.

[0070] The second helical structure 320 is composed of projections that protrude from the inner circumferential surface of the shaft 162 into the main flow path 212. The projections are formed, for example, in a helical or propeller shape. However, it is not limited to this, and the second helical structure 320 may also be composed of grooves that are recessed from the inner circumferential surface of the shaft 162 toward the outer circumferential surface. The grooves are formed, for example, in a helical or propeller shape.

[0071] The second helical structure 320 is located on the inner surface of the main flow path 212, on the side of the opening O1 that is closer to the first branch flow path 314. In other words, the second helical structure 320 is located on the inner surface of the main flow path 212, downstream of the first branch flow path 314. To put it another way, the second helical structure 320 is located on the inner surface of the main flow path 212, on the other axial side that is closer to the first branch flow path 314.

[0072] The second helical structure 320 is provided at an axial distance from the first helical structure 318. The second helical structure 320 is provided on the inner circumferential surface of the main flow path 212, upstream of the second branch flow path 316. In other words, the second helical structure 320 is provided on the inner circumferential surface of the main flow path 212, between the first branch flow path 314 and the second branch flow path 316.

[0073] The spiral direction of the second helical structure 320 is opposite to that of the first helical structure 318. In other words, the spiral direction of the second helical structure 320 is the positive direction, which is aligned with the rotational direction of the shaft 162.

[0074] The oil introduced into the main channel 212 from the opening O2 passes through the first helical structure 318 as it flows through the main channel 212. The flow velocity of the oil flowing through the main channel 212 is reduced as it collides with the protrusions of the first helical structure 318 as it passes through it.

[0075] Here, since the first helical structure 318 has a helical shape in the opposite direction to the rotation direction of the shaft 162, the lower the rotational speed of the shaft 162, the less likely the oil is to collide with the protrusions of the first helical structure 318. As a result, the oil flows more easily within the first helical structure 318. In other words, the lower the rotational speed of the shaft 162, the smaller the reduction in flow velocity before and after the oil passes through the first helical structure 318.

[0076] According to Bernoulli's theorem and the continuity equation, the smaller the flow velocity reduction, the lower the pressure of the oil after passing through the first helical structure 318, making it more difficult for oil to be injected from the first branched channel 314 formed downstream of the first helical structure 318. As a result, the amount of oil injected from the first branched channel 314 is less than that from the second branched channel 316.

[0077] Thus, at low rotational speeds of the motor 110, most of the oil circulating in the main passage 212 is injected from the second branch passage 316, and almost no oil is injected from the first branch passage 314. Therefore, the cooling mechanism 310 of this modified example can prioritize cooling the coil end 144a over the magnet 164a at low rotational speeds of the motor 110.

[0078] Figure 5 is a schematic diagram showing the configuration of the cooling mechanism 310 of the motor 110 according to this modified example at high rotation speed. As shown in Figure 5, the oil introduced into the main flow path 212 from the opening O2 passes through the first helical structure 318 in the process of flowing through the main flow path 212. The flow velocity of the oil flowing through the main flow path 212 is reduced as it collides with the protrusions of the first helical structure 318 in the process of passing through the first helical structure 318.

[0079] Here, since the first helical structure 318 has a helical shape in the opposite direction to the rotation direction of the shaft 162, the higher the rotational speed of the shaft 162, the more likely the oil is to collide with the protrusions of the first helical structure 318. As a result, it becomes more difficult for the oil to flow through the first helical structure 318. In other words, the higher the rotational speed of the shaft 162, the greater the reduction in flow velocity of the oil before and after passing through the first helical structure 318.

[0080] According to Bernoulli's theorem and the equation of continuity, the greater the reduction in flow velocity, the higher the pressure of the oil after passing through the first helical structure 318, making it easier for oil to be injected from the first branched flow path 314 formed downstream of the first helical structure 318.

[0081] Meanwhile, oil that passes through the first helical structure 318 and is not injected from the first branched flow path 314 passes through the second helical structure 320. The flow velocity of the oil circulating in the main flow path 212 is reduced as it passes through the second helical structure 320 by colliding with the protrusions of the second helical structure 320.

[0082] Here, unlike the first helical structure 318, the second helical structure 320 has a forward-facing helical shape that matches the rotational direction of the shaft 162. Therefore, the higher the rotational speed of the shaft 162, the less likely the oil is to collide with the protrusions of the second helical structure 320. As a result, the oil flows more easily through the second helical structure 320. In other words, the higher the rotational speed of the shaft 162, the smaller the reduction in flow velocity before and after the oil passes through the second helical structure 320.

[0083] According to Bernoulli's theorem and the equation of continuity, the smaller the reduction in flow velocity, the lower the pressure of the oil after passing through the second helical structure 320, making it more difficult for oil to be injected from the second branched passage 316 formed downstream of the second helical structure 320. As a result, the amount of oil injected from the second branched passage 316 is less than that from the first branched passage 314.

[0084] Thus, when the motor 110 is rotating at high speed, most of the oil circulating in the main passage 212 is injected from the first branch passage 314, and almost no oil is injected from the second branch passage 316. Therefore, the cooling mechanism 210 of this embodiment can prioritize cooling the magnet 164a over the coil end 144a when the motor 110 is rotating at high speed.

[0085] As described above, in the modified cooling mechanism 310, the spiral direction of the first helical structure 318 is opposite to the rotation direction of the shaft 162. Therefore, as the rotation speed of the rotor 160 increases, the amount of deceleration of the oil flow by the first helical structure 318 increases. On the other hand, the spiral direction of the second helical structure 320 is the forward direction opposite to the rotation direction of the shaft 162. Therefore, as the rotation speed of the rotor 160 increases, the amount of deceleration of the oil by the second helical structure 320 decreases.

[0086] In this way, by changing the axial flow velocity of the oil circulating inside the shaft 162 according to the rotational speed of the motor 110, the destination of the oil can be changed to the coil end 144a or the magnet 164a. The cooling mechanism 310 of this modified example can be formed by machining the inside of the shaft 162, without increasing the size of the shaft 162 or requiring any additional parts. Therefore, using a cooling structure with a simple configuration, the amount of coolant supplied to multiple parts of the motor 110 can be appropriately adjusted according to the rotational speed of the motor 110.

[0087] Embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

[0088] In the embodiments and modifications described above, an example was given in which both the first branch channels 214, 314 and the second branch channels 216, 316 are provided on the shaft 162. However, the invention is not limited to this, and the shaft 162 may be provided with only one of the first branch channels 214, 314 and the second branch channels 216, 316.

[0089] For example, in the above embodiment, the second branching channel 216 may not be formed in the shaft 162, and only the first branching channel 214 may be formed. In that case, the rotor core 164 having the magnet 164a may be cooled indirectly via air by the oil that has passed through the second helical structure 220 in the shaft 162.

[0090] Furthermore, in the above modified example, the second branching channel 316 may not be formed in the shaft 162, and only the first branching channel 314 may be formed. In that case, the coil end 144a may be indirectly cooled via air by the oil that has passed through the second helical structure 320 inside the shaft 162. [Explanation of Symbols]

[0091] 100 vehicles 110 Motor 140 stator 142 Stator Core 144 coils 144a Coil End 160 rotors 162 Shaft 162a Holding part 164 Rotor Core 200 Cooling device 210 Cooling mechanism 212 Main channel 214 First branch channel 216 Second branch channel 218 First helical structure 220 Second spiral structure 250 EOP 310 Cooling mechanism 314 First branch channel 316 Second branch channel 318 First helical structure 320 Second spiral structure

Claims

1. A rotor having a shaft, A stator is provided around the rotor, A main channel is formed inside the shaft so as to extend axially, and configured so that the coolant flows in one direction in the axial direction, A first branch channel is formed inside the shaft so as to extend in a direction intersecting the axial direction and branching off from the main channel, A first helical structure is provided on the inner circumferential surface of the main flow channel on one side in the axial direction of the first branch flow channel, A second helical structure is provided on the inner circumferential surface of the main flow channel, on the side in the axial direction opposite to the first branch flow channel, and is spaced apart from the first helical structure. Equipped with, The first helical structure is provided on the inner circumferential surface of the main flow channel, upstream of the first branch flow channel in the flow of the coolant. The second helical structure is provided on the inner circumferential surface of the main flow channel, downstream of the first branch flow channel in the flow of the coolant. The helical direction of the first helical structure is opposite to the helical direction of the second helical structure. The spiral direction of the first helical structure is the positive direction, which is aligned with the rotational direction of the shaft. The helical direction of the second helical structure is opposite to the forward direction. The first branch channel is a channel for supplying the coolant to the stator. Motor.

2. The shaft further comprises a second branch channel formed to extend in a direction intersecting the axial direction and branching off from the main channel, The second branch channel is provided downstream of the second helical structure in the flow of the coolant. The second branch channel is a channel for supplying the coolant to the magnet of the rotor. The motor according to claim 1.

3. A rotor having a shaft, A stator is provided around the rotor, A main channel is formed inside the shaft so as to extend axially, and configured so that the coolant flows in one direction in the axial direction, A first branch channel is formed inside the shaft so as to extend in a direction intersecting the axial direction and branching off from the main channel, A first helical structure is provided on the inner circumferential surface of the main flow channel on one side in the axial direction of the first branch flow channel, A second helical structure is provided on the inner circumferential surface of the main flow channel, on the side in the axial direction opposite to the first branch flow channel, and is spaced apart from the first helical structure. Equipped with, The helical direction of the first helical structure is opposite to the helical direction of the second helical structure. As the rotational speed of the rotor increases, the amount of deceleration of the coolant flow by the first helical structure decreases, and the amount of deceleration of the coolant flow by the second helical structure increases. Motor.

4. A rotor having a shaft, A stator is provided around the rotor, A main channel is formed inside the shaft so as to extend axially, and configured so that the coolant flows in one direction in the axial direction, A first branch channel is formed inside the shaft so as to extend in a direction intersecting the axial direction and branching off from the main channel, A first helical structure is provided on the inner circumferential surface of the main flow channel on one side in the axial direction of the first branch flow channel, A second helical structure is provided on the inner circumferential surface of the main flow channel, on the side in the axial direction opposite to the first branch flow channel, and is spaced apart from the first helical structure. Equipped with, The helical direction of the first helical structure is opposite to the helical direction of the second helical structure. At least one of the pitch number, blade angle, and length of the first helical structure is set so that the amount of deceleration of the coolant flow by the first helical structure becomes a desired amount of deceleration. At least one of the pitch number, blade angle, and length of the second helical structure is set so that the amount of deceleration of the coolant flow by the second helical structure becomes a desired amount of deceleration. Motor.

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