Motor with reduction mechanism

Abstract

This speed reduction mechanism-equipped motor GM comprises: a motor M that is housed within a motor housing 1; and a speed reduction mechanism 3 that is housed within a gear housing 2. The speed reduction mechanism 3 is composed of a hypoid gear and is equipped with a pinion P and a ring gear R. The motor housing 1 is equipped with a heat exchanger 5 that performs heat exchange between gear oil 6 introduced from the gear housing 2 side and a refrigerant for the motor. Between the gear housing 2 and the motor housing 1, an oil circulation path is disposed which allows the gear oil 6 introduced from the gear housing 2 side to pass through the heat exchanger 5 and to return to the gear housing 2. The speed reduction mechanism-equipped motor cools the reduction mechanism 3 that is prone to relatively high temperatures.

Description

[Technical Field]

[0001] The present invention relates to a motor with a speed reduction mechanism used as a drive source for an electric vehicle, for example. [Background technology]

[0002] A conventional motor with a speed reduction mechanism is described in Patent Document 1, under the title of drive unit for electric vehicles. The motor with a speed reduction mechanism described in Patent Document 1 includes a through shaft that transmits motor torque to a transmission gear, a pinion shaft that transmits the torque transmitted via the transmission gear to an axle, a drive pinion that rotates in response to rotation of the pinion shaft, and a ring gear that meshes with the drive pinion, and is configured so that rotation of the ring gear rotates the axle shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-61200 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the above-described conventional motor with a speed reduction mechanism is used in an electric vehicle, the speed reduction mechanism and the motor exchange heat with each other depending on the driving conditions, and there is a risk that the speed reduction mechanism side in particular will become too hot.

[0005] The present invention has been made in view of the above-mentioned conventional situation, and has as its object to provide a motor with a speed reduction mechanism that can cool the speed reduction mechanism, which tends to become relatively hot. [Means for solving the problem]

[0006] A motor with a reduction gear according to the present invention includes a motor housed in a motor housing and a reduction gear housed in a gear housing. The reduction gear comprises a hypoid gear and includes a pinion provided on the motor output shaft and a ring gear with which the pinion engages. The motor housing includes a heat exchanger that exchanges heat between gear oil introduced from the gear housing side and a motor coolant that cools the motor. The motor with a reduction gear includes an oil circulation path between the gear housing and the motor housing that passes gear oil introduced from the gear housing side into the motor housing through the heat exchanger and returns it to the gear housing. [Effects of the Invention]

[0007] The motor with a speed reduction mechanism according to the present invention employs the above-described configuration, making it possible to cool the speed reduction mechanism, which tends to become relatively hot. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional explanatory view showing an embodiment of a motor with a reduction mechanism according to the present invention; [Figure 2] FIG. 10 is a cross-sectional view illustrating one of the spiral structures provided in the oil flow passage of the output shaft. [Figure 3] FIG. 2 is a cross-sectional view illustrating a heat exchanger. [Figure 4] FIG. 2 is a perspective view schematically showing a heat exchanger. [Figure 5] FIG. 2 is a plan view schematically showing the inside of the heat exchanger. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment The motor GM with a speed reduction mechanism shown in Figure 1 includes a motor M housed in a motor housing 1 and a speed reduction mechanism 3 housed in a gear housing 2. The speed reduction mechanism 3 is made up of a hypoid gear and includes a pinion P provided on an output shaft 4 of the motor M and a ring gear R with which the pinion P engages.

[0010] The illustrated motor GM with a reduction gear mechanism constitutes the drive source of an electric vehicle. The motor M is oriented with the axis of the output shaft 4 horizontal. The reduction gear 3 is oriented with the axis of the ring gear R horizontal and perpendicular to the axis of the output shaft 4, and transmits the rotation of the motor M to an axle (not shown) via a differential mechanism D (part of which is shown).

[0011] In the above-mentioned reduction gear motor GM, the motor housing 1 is equipped with a heat exchanger 5 that exchanges heat between gear oil introduced from the gear housing 2 side and a motor refrigerant that cools the motor M. Gear oil 6 is stored in the gear housing 2. The above-mentioned reduction gear motor GM has an oil circulation path between the gear housing 2 and the motor housing 1 that passes the gear oil 6 introduced from the gear housing 2 side through the heat exchanger 5 and returns it to the gear housing 2.

[0012] The oil circulation path is provided within the gear housing 2 with a ring gear R, a catch tank 7 that collects gear oil 6 scooped up by the rotating ring gear R, and an oil flow passage 8 that is formed on the axis of the output shaft 4 and returns the gear oil 6 discharged from the heat exchanger 5 to the gear housing 2. Therefore, the heat exchanger 5 exchanges heat between the gear oil 6 introduced from the catch tank 7 and the motor refrigerant.

[0013] 2, the oil flow passage 8 of the output shaft 4 has a circular cross section, is open at both ends of the output shaft 4, and is provided with a helical structure 9 that transfers the gear oil 6 discharged from the heat exchanger 5 to the gear housing 2. This helical structure 9 is a so-called Archimedean screw, and is provided with a shaft 9A disposed at the center of the oil flow passage 8 and a helical plate 9B provided along the axial direction of this shaft 9A, and rotates together with the output shaft 4.

[0014] When viewed from the axial direction of the output shaft 4, the heat exchanger 5 is arranged in at least one of the first and second quadrants centered on the output shaft 4, and as shown schematically in Figures 3 and 4, has a plurality of oil flow paths F1 through which gear oil 6 flows along the axial direction of the output shaft 4, and a plurality of refrigerant flow paths F2 through which motor refrigerant flows also along the axial direction of the output shaft 4. The heat exchanger 5 has a structure in which the oil flow paths F1 and the refrigerant flow paths F2 are arranged in parallel and alternately in the vertical direction.

[0015] The oil flow path F1 and the refrigerant flow path F2 are separated from each other by a partition wall, and for example, fins or the like may be placed on the partition wall to improve heat exchange efficiency. In practice, each of the housings 1, 2 and the motor M may have fluid flow paths integrally formed therewith, such as a water jacket. The motor refrigerant is, for example, water or oil. In the heat exchanger 5, the flow directions of the gear oil 6 and the motor refrigerant may be opposite to each other or may be the same.

[0016] 5, the heat exchanger 5 has an uppermost oil flow path F1 that communicates with the catch tank 7 and a branch path Fb that intersects with the adjacent refrigerant flow path F2 and leads to the lower oil flow path F1. The heat exchanger 5 in the illustrated example has a branch path Fb in the middle of the uppermost oil flow path F1 that leads to the second oil flow path F1 from the top in FIG. 5, and the second oil flow path F1 has a branch path Fb downstream of the branch path Fb (to the right in FIG. 5) that leads to the third oil flow path F1.

[0017] The heat exchanger 5 described above can be manufactured using a three-dimensional modeling device (a so-called 3D printer) because the branch passage Fb has a multi-level intersection structure. In this case, the heat exchanger 5 may be molded as a whole, or each section divided in the thickness direction or into small parts may be molded separately and then assembled. Alternatively, the heat exchanger 5 may be molded as a whole by casting each section divided in the thickness direction or into small parts, and then assembled.

[0018] As a result, the multiple oil flow paths F1 have a structure in which they branch into multiple paths toward the downstream side as a whole. Furthermore, the oil flow path F1 has a structure in which the cross-sectional area increases toward the downstream side. That is, as shown in FIG. 5, the oil flow path F1 has a width W2 at its downstream end that is larger than the width W1 at its upstream end, and the width gradually increases from the upstream end to the downstream end. This facilitates oil flow through the oil flow path F1, which can contribute to improved cooling performance. Furthermore, when the heat exchanger 5 is manufactured by casting as described above, it is advantageous in that the mold forming the oil flow path F1 can be easily removed. The cross-sectional area of ​​the oil flow path F1 may change continuously as shown in the figure, or may change in stages.

[0019] As described above, the reduction gear motor GM having the above-described configuration reduces the rotation of the motor M using the reduction gear 3 and transmits it to the axle. At this time, the reduction gear motor M scoops up gear oil 6 stored in the gear housing 2 with the tooth surface of the rotating ring gear R and collects it in a catch tank 7, as shown by the arrow in Figure 1.

[0020] Furthermore, the reduction gear motor GM introduces the gear oil 6 collected in the catch tank 7 into the heat exchanger 5 via a path not shown. The heat exchanger 5 branches the gear oil 6 introduced into the uppermost oil flow path F1 into multiple paths downstream, and also circulates the motor refrigerant through the refrigerant flow path F2, thereby exchanging heat between the relatively high-temperature gear oil 6 and the relatively low-temperature motor refrigerant.

[0021] Furthermore, the reduction gear motor GM introduces the gear oil 6 discharged from the heat exchanger 5 through a path in the motor housing 1 into the oil flow passage 8 of the output shaft 4. At this time, the reduction gear motor GM transfers the introduced gear oil 6 to the pinion gear P side, i.e., the gear housing 2 side, as the spiral structure 9 provided in the oil flow passage 8 rotates together with the output shaft 4, and then discharges the gear oil 6 from the end of the output shaft 4 and returns it to the gear housing 2.

[0022] In this way, the motor GM with reduction gear mechanism continuously cools and circulates the gear oil 6 as described above while the motor M is rotating, thereby cooling the reduction gear mechanism 3, which tends to become relatively hot. Furthermore, since the motor GM with reduction gear mechanism uses a hypoid gear for the reduction gear mechanism 3, in addition to the cooling function described above, a reduction ratio equivalent to that of a helical gear can be obtained and it can also contribute to space saving.

[0023] In addition, the motor GM with reduction gear mechanism has an oil circulation path formed by the ring gear R, catch tank 7, heat exchanger 5, and oil flow passage 8 of the output shaft 4, so the gear oil 6 can be cooled and circulated without using auxiliary equipment such as an oil pump, which reduces the number of parts and manufacturing costs, and also allows the output shaft 4 to be cooled.

[0024] Furthermore, since the motor GM with reduction gear mechanism is equipped with a spiral structure 9 in the oil flow passage 8, the gear oil 6 can be smoothly transported by the rotation of the output shaft 4 without requiring any other power, thereby further improving the circulation function of the gear oil 6.

[0025] Furthermore, in the motor GM with a reduction mechanism, in the heat exchanger 5 located on the upper side of the motor housing 1, the gear oil 6 introduced from the catch tank 7 into the top oil flow path F1 falls naturally and branches into multiple paths downstream.

[0026] As a result, the motor GM with reduction mechanism can reduce the length dimension (dimension in the flow direction) of the heat exchanger 5, allowing for highly efficient heat exchange.In addition, since the only introduction point for the gear oil 6 from the catch tank 7 is the uppermost oil flow path F1, backflow of the gear oil 6 toward the reduction mechanism 3 can be prevented.

[0027] Furthermore, since the heat exchanger 5 has multiple oil flow paths F1 arranged along the axial direction of the output shaft 4, the gear oil 6 is easily collected at the end of the oil flow passage 8, i.e., the end opposite the pinion P, which can contribute to improving the circulation function of the gear oil 6.

[0028] Furthermore, in the motor GM with a reduction mechanism, the oil flow path F1 in the heat exchanger 5 has a structure in which the cross-sectional area increases toward the downstream side, which allows the flow of the gear oil 6 to be even smoother, thereby further improving the heat exchange rate with the motor refrigerant and the circulation function of the gear oil 6.

[0029] The configuration of the motor with a speed reduction mechanism according to the present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0030] 1 Motor housing 2 gear housing 3 Reduction mechanism 4 output shaft 5 Heat exchanger (oil circulation path) 6. Gear oil 7 Catch tank (oil circulation path) 8 Oil flow passage (oil circulation path) 9 Spiral structure F1 oil flow path F2 refrigerant flow path Fb Fork GM motor with speed reducer Medium motor P Pinion R ring gear

Claims

1. A motor with a reduction mechanism includes a motor accommodated in a motor housing and a reduction mechanism accommodated in a gear housing, the reduction mechanism is made of a hypoid gear and includes a pinion provided on an output shaft of the motor and a ring gear with which the pinion engages, the motor housing includes a heat exchanger that exchanges heat between gear oil introduced from the gear housing side and a motor coolant that cools the motor, A motor with a reduction gear mechanism, characterized in that an oil circulation path is provided between the gear housing and the motor housing, through which the gear oil introduced into the motor housing from the gear housing side passes through the heat exchanger and returns to the gear housing.

2. The gear oil is stored in the gear housing, The oil circulation path is a catch tank disposed within the gear housing for collecting the gear oil scooped up by the rotating ring gear; an oil flow passage formed on the axis of the output shaft and returning the gear oil discharged from the heat exchanger into the gear housing, 2. The motor with a reduction gear mechanism according to claim 1, wherein the heat exchanger exchanges heat between the gear oil introduced from the catch tank and the motor coolant.

3. 3. The motor with a reduction gear mechanism according to claim 2, further comprising a spiral structure within the oil flow passage that transports the gear oil discharged from the heat exchanger to the gear housing side as the output shaft rotates.

4. The heat exchanger is When viewed from the axial direction of the output shaft, the gear is disposed in at least one of a first quadrant and a second quadrant centered on the output shaft, The gear oil is passed through a plurality of oil flow paths along the axial direction of the output shaft, and the motor coolant is passed through a plurality of refrigerant flow paths along the axial direction of the output shaft. The gear oil is passed through a plurality of refrigerant flow paths along the axial direction of the output shaft, and the oil flow paths and the refrigerant flow paths are arranged in parallel and alternately in the vertical direction. The plurality of oil flow paths have an uppermost oil flow path that communicates with the catch tank and has a branch path that intersects with an adjacent refrigerant flow path and leads to a lower oil flow path, 3. The motor with a reduction gear mechanism according to claim 2, wherein the oil flow path has a structure in which the oil flow path is branched into a plurality of paths downstream as a whole.

5. 6. The motor with a reduction gear mechanism according to claim 5, wherein the oil flow path has a structure in which a cross-sectional area increases toward the downstream side.

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