Power transmission device

Abstract

To supply oil to the inside of a rotor shaft and to supply oil from the inside of the rotor shaft to a motor chamber.SOLUTION: A power transmission device is provided which comprise: a case for housing a motor and a gear mechanism; a rotary shaft extending inside a hollow rotor shaft; an in-shaft space formed between the rotor shaft and the rotary shaft: spiral structure which is disposed in at least one of the inner peripheral part of the rotor shaft and the outer peripheral part of the rotary shaft at one end side of the rotor shaft, and which force feeds oil in the axial direction by relative rotation of the rotor shaft and the rotary shaft and supplies oil into the in-shaft space; and a through-hole penetrating into the rotor shaft in the radial direction, providing communication between the in-shaft space in a motor chamber where the motor is housed, and a shaft outer space where the rotor is arranged, and making oil supplied into the in-shaft space by the spiral structure circulate from the in-shaft space to the shaft outer space. The spiral structure axially extends to a position where the through-hole is disposed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power transmission device. [Background technology]

[0002] Patent Document 1 discloses that a groove is provided between a hollow rotor shaft and a rotating shaft disposed inside the rotor shaft inside a case that houses a motor and a gear mechanism, and the groove pressure-feeds oil in the axial direction due to relative rotation between the rotor shaft and the rotating shaft. In the configuration described in Patent Document 1, oil supplied to one end of the rotor shaft is pressure-fed in the axial direction through the internal space of the rotor shaft by the groove toward the other end of the rotor shaft, making it possible to supply oil to the spline-fit portion between the other end of the rotor shaft and the gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-57758 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration described in Patent Document 1, oil is pressure-fed from one end of the rotor shaft into the interior of the rotor shaft by the groove, passes through the interior of the rotor shaft, and is returned to the gear chamber from the other end of the rotor shaft, and is not supplied from the interior of the rotor shaft to the motor chamber.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a power transmission device that can supply oil to the inside of a rotor shaft and can supply oil from the inside of the rotor shaft to a motor chamber. [Means for solving the problem]

[0006] The present invention provides a power transmission device comprising: a case that houses a motor and a gear mechanism; a rotating shaft that extends inside a hollow rotor shaft that rotates integrally with the rotor of the motor and outputs power transmitted from the gear mechanism; and an intra-shaft space formed between the rotor shaft and the rotating shaft, wherein the device comprises a spiral structure provided on at least one of the inner circumference of the rotor shaft and the outer circumference of the rotating shaft at one end side of the rotor shaft, which pressurizes oil in the axial direction as the rotor shaft and the rotating shaft rotate relative to each other, thereby supplying the oil to the intra-shaft space; and a through hole that penetrates the rotor shaft radially, connects the intra-shaft space to an off-shaft space in which the rotor is disposed within a motor chamber that houses the motor, and allows the oil supplied to the intra-shaft space by the spiral structure to circulate from the intra-shaft space to the off-shaft space, and wherein the spiral structure extends in the axial direction to the position where the through hole is provided. [Effects of the Invention]

[0007] In the present invention, oil can be supplied to the inside of the rotor shaft, and oil can also be supplied from the inside of the rotor shaft to the motor chamber. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram schematically illustrating a power transmission device according to an embodiment. [Figure 2] FIG. 2 is a diagram for explaining the structure of one end of the rotor shaft. [Figure 3] FIG. 3 is a diagram for explaining a case where oil is pumped in the axial direction by a spiral structure. [Figure 4] FIG. 4 is a diagram illustrating the structure of one end of the rotor shaft in the first modified example. [Figure 5] FIG. 5 is a diagram illustrating the structure of one end of the rotor shaft in the second modified example. [Figure 6] FIG. 6 is a diagram illustrating the structure of one end of the rotor shaft in the third modified example. [Figure 7]FIG. 7 is a diagram for explaining a case where the rotor shaft rotates in the reverse direction in the third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a power transmission device according to an embodiment of the present invention will be specifically described, but the present invention is not limited to the embodiment described below.

[0010] FIG. 1 is a diagram schematically illustrating a power transmission device according to an embodiment. The power transmission device 1 is configured with an electric power train such as a single-shaft e-Axle. The power transmission device 1 includes a motor 2, a PCU 3, a gear mechanism, and an intermediate shaft 4. Note that the gear mechanism is not shown in FIG. 1 and other figures.

[0011] The power transmission device 1 is a drive unit that integrates a motor 2, a PCU 3, and a gear mechanism, and is mounted on an electric vehicle. The power transmission device 1 inputs the power output from the motor 2 to the gear mechanism and transmits the power to an intermediate shaft 4 and a drive shaft 5 via the gear mechanism. The gear mechanism includes a planetary gear mechanism and a differential device. The power input from the motor 2 to the planetary gear mechanism is transmitted to the differential device via the planetary gear mechanism. The differential device is connected to the left and right drive shafts 5. The intermediate shaft 4 is a rotating shaft that connects the differential device and one of the drive shafts 5. Power is transmitted to one of the drive shafts 5 via the intermediate shaft 4, and power is transmitted directly from the differential device to the other drive shaft 5. The power transmitted to the drive shafts 5 is transmitted to the wheels.

[0012] In the power transmission device 1, a motor 2, a PCU 3, a gear mechanism, and an intermediate shaft 4 are housed inside a case 10. The case 10 forms a motor chamber 11 that houses the motor 2, a gear chamber 12 that houses the gear mechanism, and a PCU chamber that houses the PCU 3. The PCU chamber is provided above the motor chamber 11 and the gear chamber 12. An oil reservoir 13 is provided at the bottom of the case 10. The oil reservoir 13 stores the oil housed inside the case 10. The oil is a refrigerant that cools the motor 2 and the PCU 3. The oil stored in the oil reservoir 13 is supplied to the motor 2 and the PCU 3 by an oil pump 6. The oil pump 6 discharges the oil drawn from the oil reservoir 13 through a filter and pumps the oil to case oil passages and the like provided in the case 10. In the case 10, the oil supplied to the PCU 3 cools the PCU 3 in the PCU chamber, flows from the PCU chamber into the motor chamber 11 below, and cools the motor 2. After cooling the motor 2, the oil returns to the oil reservoir 13 by gravity.

[0013] The motor 2 includes a rotor 21, a stator 22, and a rotor shaft 23. The rotor 21 rotates integrally with the rotor shaft 23. The stator 22 includes a coil 22a wound around a stator core. The stator 22 is fixed to the case 10. The rotor shaft 23 is a hollow rotating shaft. The rotor shaft 23 is rotatably supported relative to the case 10 by bearings attached to both ends. The rotor shaft 23 is spline-fitted with a sun gear 31 of the planetary gear mechanism. An intermediate shaft 4 is disposed inside the rotor shaft 23.

[0014] The intermediate shaft 4 is a rotating shaft that extends inside the rotor shaft 23 and outputs the power transmitted from the gear mechanism. The intermediate shaft 4 and the rotor shaft 23 rotate relative to each other on the same central rotation axis. One end of the intermediate shaft 4 is connected to the drive shaft 5. An end of the drive shaft 5 is fitted into the inner peripheral portion of the intermediate shaft 4 and is disposed inside the rotor shaft 23. The intermediate shaft 4 and the drive shaft 5 extend axially inside the rotor shaft 23. The power transmission device 1 has an intra-shaft space 14 formed between the rotor shaft 23 and the intermediate shaft 4.

[0015] As shown in FIG. 2, the power transmission device 1 has a helical structure 40 provided on the outer periphery of the intermediate shaft 4 and a through hole 23a that penetrates the rotor shaft 23 in the radial direction. The intermediate shaft 4 has the helical structure 40 provided on the outer periphery on one end side of the rotor shaft 23. The helical structure 40 is formed of a groove or a protrusion. The helical structure 40 is formed of a helical groove or a helical protrusion. As shown in FIG. 3, the helical structure 40 is a structure that supplies oil to the shaft space 14 by pressurizing oil in the axial direction when the rotor shaft 23 and the intermediate shaft 4 rotate relative to each other. The helical structure 40 is effective in sending oil from outside the shaft center into the shaft space 14. The helical structure 40 extends in the axial direction to the position where the through hole 23a is provided. In the axial direction, the helical structure 40 is formed to include the range from one end of the rotor shaft 23 to the through hole 23a of the rotor shaft 23.

[0016] The through hole 23a communicates the in-shaft space 14 with the off-shaft space 15 in which the rotor 21 is disposed within the motor chamber 11. As shown in Fig. 3, the through hole 23a allows oil supplied to the in-shaft space 14 by the spiral structure 40 to flow from the in-shaft space 14 to the off-shaft space 15. When the rotor shaft 23 and the intermediate shaft 4 rotate, centrifugal force causes the oil in the in-shaft space 14 to flow outward in the radial direction from the through hole 23a.

[0017] As shown in FIG. 2 , the rotor 21 is provided with a rotor oil passage 21a through which oil flows axially inside the rotor 21. A guide member 24 is attached to one end of the rotor 21 and guides oil that flows radially outward from the through-hole 23a into the rotor oil passage 21a. The guide member 24 is formed into a shape that includes a portion that faces radially the opening of the through-hole 23a and a portion that faces axially the opening of the rotor oil passage 21a. The guide member 24 rotates integrally with the rotor 21 and rotor shaft 23. In the power transmission device 1, the spiral structure 40 allows oil supplied to the in-shaft space 14 to be supplied from the in-shaft space 14 to the off-shaft space 15, thereby supplying the oil to the rotor oil passage 21a. The oil flowing axially through the rotor oil passage 21a can cool the interior of the rotor 21, improving the cooling performance of the rotor 21.

[0018] As described above, according to the embodiment, oil can be supplied to the axial center of the rotor shaft 23 without increasing the size of the power transmission device 1 having a single-axis type structure, and oil in the intra-axial space 14 can be supplied to the off-axial space 15 of the motor chamber 11.

[0019] In the power transmission device 1 of the embodiment, a structure has been described in which the spiral structure for supplying oil to the shaft space 14 is provided only on the intermediate shaft 4, but the present invention is not limited to this. The spiral structure may be provided on at least one of the rotor shaft 23 and the intermediate shaft 4. Modified power transmission devices 1 can be configured in a number of structures, as shown in FIGS. 4 to 7. A first modified example has a spiral structure only on the rotor shaft 23. A second modified example has a spiral structure on both the intermediate shaft 4 and the rotor shaft 23. A third modified example has a structure in which the spiral structures of the intermediate shaft 4 and the rotor shaft 23 are reversed.

[0020] As shown in FIG. 4 , the power transmission device 1 of the first modified example has a helical structure 50 provided on the inner periphery of the rotor shaft 23. The rotor shaft 23 has the helical structure 50 provided on the inner periphery at one end side of the rotor shaft 23. The helical structure 50 is formed of a groove or a protrusion. The helical structure 50 is formed of a helical groove or a helical protrusion. The helical structure 50 is a structure that pressurizes oil in the axial direction by relative rotation between the rotor shaft 23 and the intermediate shaft 4, thereby supplying the oil to the intra-shaft space 14. The helical structure 50 provided on the inner periphery of the rotor shaft 23 is effective in further sending oil that has entered the intra-shaft space 14 but has stuck to the inner axial wall of the rotor shaft 23 due to centrifugal force, further inward in the axial direction, and in preventing oil from leaking out of the axis in the axial direction.

[0021] 5, the power transmission device 1 of the second modified example has a helical structure 40 provided on the outer periphery of the intermediate shaft 4 and a helical structure 50 provided on the inner periphery of the rotor shaft 23. In the second modified example, the helical structure is provided on both the rotor shaft 23 and the intermediate shaft 4 at one end side of the rotor shaft 23.

[0022] As shown in Figure 6, in the power transmission device 1 of the third modified example, the spiral structure 40 of the intermediate shaft 4 and the spiral structure 50 of the rotor shaft 23 are configured so that their respective spiral structures are in opposite directions. The configuration of the second modified example is effective in supplying oil to the intra-shaft space 14 when the motor 2 is rotating in the forward direction, but acts to expel oil outside the axis when the motor 2 is rotating in the reverse direction. In contrast, the third modified example is compatible with both forward and reverse rotation, as shown in Figures 6 and 7. [Explanation of symbols]

[0023] 1 Power transmission device 2 motors 4 Intermediate shaft 5 drive shaft 10 cases 11 Motor Room 12 Gear room 14 Intraaxial space 15 Off-axis space 21 rotor 23 Rotor shaft 23a Through hole 40 Spiral structure

Claims

[Claim 1] a case that houses the motor and the gear mechanism; a rotary shaft that extends through a hollow rotor shaft that rotates integrally with the rotor of the motor and outputs the power transmitted from the gear mechanism; an intra-shaft space formed between the rotor shaft and the rotating shaft; A power transmission device comprising: a spiral structure provided on at least one of an inner circumferential portion of the rotor shaft and an outer circumferential portion of the rotating shaft at one end side of the rotor shaft, the spiral structure pressurizing oil in the axial direction by relative rotation of the rotor shaft and the rotating shaft to supply the oil to the axial space; a through hole that radially penetrates the rotor shaft, communicates the intra-shaft space with an off-shaft space in which the rotor is disposed within a motor chamber that houses the motor, and allows the oil supplied to the intra-shaft space by the spiral structure to circulate from the intra-shaft space to the off-shaft space; Equipped with The spiral structure extends in the axial direction to a position where the through hole is provided. A power transmission device characterized by:

Images