JP7421523B2 - transaxle - Google Patents

Description

The present invention relates to a transaxle.

In recent years, hybrid vehicles (series hybrid vehicles), in which the engine drives a power generation motor (MG1) to generate electricity, and the drive motor (MG2) is driven by the electric power supplied to it, have become popular. Electric vehicles that run are provided. Furthermore, a transaxle equipped with a motor is provided as a transaxle used in a hybrid vehicle or an electric vehicle.

In a transaxle equipped with a motor, a gear-side shaft is connected in series to the motor shaft (coaxially connected). For example, as shown in FIG. 4, a motor shaft 117 and a gear shaft 118 are coaxially connected. In this way, another shaft body (gear shaft) is connected in series to the motor shaft.

Bearings are attached to two shaft bodies (motor shaft and gear shaft) connected in series, and these shaft bodies are attached to the transaxle case via the bearings. As a device including such a shaft body and bearing, for example, Patent Document 1 listed below discloses a vehicle drive device in which a rotor shaft is attached to a case via a bearing.

JP2020-28213A

By the way, a conventional transaxle equipped with a motor is provided with a housing portion into which a bearing is fitted, and the motor shaft and gear shaft are attached to the housing portion via the bearing. Further, in the conventional transaxle, when assembling the bearing to the housing part, there was a problem that the bearing interfered with the housing part, making it difficult to assemble it.

In order to deal with such problems, it may be possible to increase the opening diameter of the housing portion. However, if the diameter of the housing portion is increased, there is a concern that the housing portion will be worn out due to the occurrence of creep, and the durability strength will deteriorate. Furthermore, in order to cope with deterioration of durability and strength due to creep, it is also possible to provide an O-ring on the outer diameter of the bearing to prevent rotation. However, there is a problem in that providing an O-ring increases cost.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a transaxle that can suppress the occurrence of creep while suppressing an increase in cost and can cope with the problem of difficulty in assembling a bearing.

Here, in order to solve the above-mentioned problem, the inventors of the present invention first investigated the causes of difficulty in assembling. As a result, when the motor chamber side bearing (first bearing) is press-fitted, the gear chamber side opening of the housing part is deformed, making it difficult to assemble the gear chamber side bearing (second bearing). found.

Specifically, as shown in FIG. 4, a conventional transaxle 100 including a motor 112 is provided with a housing portion 144 into which a bearing 160 is fitted, and the motor shaft 117 and gear shaft 118 It is attached to the housing part 144 via the housing part 144. Further, as shown in FIG. 4, the motor shaft 117 and another shaft body (for example, a gear shaft 118) are coaxially connected, and a gear is located on the back side of the bearing (first bearing 160a) on the motor 112 side. The positional relationship is such that the side bearing (second bearing 160b) is arranged. That is, the bearing 160 (first bearing 160a) on the motor shaft 117 side and the bearing 160 (second bearing 160b) on the gear shaft 118 side are in a back-to-back positional relationship.

Here, when attaching the bearing to the shaft, an inner diameter press-fitting method is generally used in which the shaft is press-fitted into the bearing 160. However, the motor shaft 117 is affected by the magnetic field when assembled. Therefore, in consideration of the influence of the magnetic field, force during press-fitting, and suppression of misalignment, it is convenient to attach the motor shaft 117 to the inner ring of the bearing 160 (first bearing 160a) with a clearance fit. Therefore, on the motor shaft 117 side, the first bearing 160a is first press-fitted (outer diameter press-fitted) into the housing portion 144, and then the motor shaft 117 is inserted into the first bearing 160a with a clearance fit.

On the other hand, on the gear shaft 118 side, the outer ring of the second bearing 160b is fitted into the housing portion 144 with the gear shaft 118 press-fitted into the inner ring of the second bearing 160b. That is, on the gear shaft 118 side, the gear shaft 118 is attached to the second bearing 160b by press-fitting the inner diameter, and the second bearing 160b is a clearance fit with respect to the housing portion 144.

However, when the first bearing 160a (bearing 160 on the motor 112 side) is press-fitted, the housing portion 144 may be deformed and the diameter of the tip of the housing portion 144 on the gear chamber 132 side may be reduced (arrow A in FIG. 4). reference). That is, the housing portion 144 is deformed so that the opening diameter on the motor chamber 131 side is opened by press-fitting the outer ring, and the opening on the opposite side (gear chamber 132 side) is contracted. As a result, the second bearing 160b may get caught on the tip of the housing portion 144, and the second bearing 160b may not be assembled. In this manner, in the conventional transaxle 100, the housing portion 144 is deformed by press-fitting one bearing (the first bearing 160a) to the outer diameter, and the entrance of the other bearing (the second bearing 160b) is narrowed. As a result, it may become difficult to assemble the second bearing 160b.

Upon further investigation, the inventors of the present invention discovered that the problem of difficulty in assembling the bearing can be improved by providing a notch (groove for deformation relief) in the housing. reached.

To explain more specifically, there is a notch (groove) between the part of the housing part in which the first bearing is accommodated (first fitting part) and the part in which the second bearing is accommodated (second fitting part). By inserting the groove, deformation of the housing part (deformation due to outer diameter press-fitting) when the bearing is press-fitted into the housing part can be absorbed by the groove part. That is, deformation of the housing part when the first bearing is press-fitted into the housing part can be absorbed by the groove part, and the opening of the second fitting part can be made difficult to deform. Thereby, interference between the bearing and the housing portion can be suppressed, and the problem of difficulty in assembling the bearing can be improved.

(1) The transaxle of the present invention provided based on the above findings includes at least one electric motor, at least two shaft bodies connected in series, a case body housing the electric motor and the shaft body, of the two shafts, the shaft on the electric motor side is the first shaft, and the other is the second shaft; It has a first bearing, a second bearing attached to the second shaft body, and a housing part formed in the case body and in which the first bearing and the second bearing are housed, the housing part is provided with a first fitting part into which the first bearing is fitted, a second fitting part into which the second bearing is fitted, and a groove formed as a groove in the housing part, and The groove portion is formed on the inner circumferential surface of the housing portion between the first fitting portion and the second fitting portion.

According to the transaxle of the present invention, deformation of the housing portion when the first bearing is press-fitted into the housing portion can be absorbed by the groove portion, and deformation of the opening of the second fitting portion can be suppressed. Thereby, the transaxle of the present invention can suppress interference between the bearing and the housing portion, and can improve the problem of difficulty in assembling the bearing.

Further, according to the transaxle of the present invention, it is not necessary to increase the outer diameter of the housing portion, and deterioration in durability and strength due to creep can be suppressed. Further, according to the transaxle of the present invention, since the occurrence of creep can be suppressed without increasing the outer diameter of the housing portion, it is not necessary to provide an O-ring or the like as a countermeasure against creep. Therefore, it is possible to suppress deterioration in durability and strength due to creep while suppressing an increase in cost.

Furthermore, in the transaxle of the present invention, the groove can function as an oil reservoir. This can be expected to improve lubrication, especially for bearings where oil shortages are a concern. To explain in more detail, there is a concern that oil may decrease between the bearings when the rotation of the motor (electric motor) decreases or stops. In contrast, in the transaxle of the present invention, the groove functions as an oil reservoir. As a result, in the transaxle of the present invention, improved lubrication of the bearing can be expected.

Further, in the transaxle of the present invention, by providing the groove portion, the housing portion can be easily elastically deformed, and generation of abnormal noise due to eccentric rotation of the shaft body can be suppressed.

To explain in more detail, a shaft body made up of two shaft bodies (for example, a motor shaft and a gear shaft) has slight defects in various places, such as the gap between the bearing and the transaxle case, and the spline between the shaft bodies. There is a gap. Therefore, it is difficult for the shaft unit to be configured as a completely straight shaft, and a slight inclination occurs. Furthermore, if the inclination of the shaft unit becomes large, it rotates eccentrically in a dogleg shape, which may generate abnormal noise.

Here, in the transaxle of the present invention, the groove portion provided in the portion that receives the load due to the rotation of the shaft body (between the first fitting portion and the second fitting portion of the housing portion) functions as a buffer portion. . As a result, when the two shaft bodies (for example, the motor shaft and the gear shaft) are tilted in a dogleg shape, resulting in eccentric rotation, the tilt can be absorbed. As a result, the effect of suppressing abnormal noise that occurs when the shaft body rotates in an inclined state can be expected.

(2) In the transaxle of the present invention, the groove portion may be formed in an annular shape on the inner peripheral surface of the housing portion.

According to the above configuration, it is possible to suppress unevenness in the deformation suppressing effect of the housing portion. That is, when the first bearing is press-fitted into the housing part, the deformation of the housing part can be absorbed by the groove substantially uniformly in the circumferential direction.

Here, the inventors of the present invention investigated the size of the groove, and found that when the depth (depth in the radial direction) of the groove is larger than the size in the width direction (gap width), the housing part deforms. It was found that the inhibitory effect was high.

(3) In the transaxle of the present invention, the groove portion has a predetermined depth from the inner peripheral surface of the housing portion, and the depth of the groove portion is preferably larger than the width dimension.

According to the above-described configuration, the effect of suppressing deformation of the housing portion can be enhanced.

(4) In the transaxle of the present invention, the first shaft body is a motor shaft of the electric motor, the first bearing is press-fitted on an outer diameter with an outer ring press-fitted into the housing part, and the first shaft body is a motor shaft of the electric motor. The uniaxial body may be fitted into the first bearing with a clearance fit.

According to the above configuration, when assembling the motor, it is possible to assemble the motor while suppressing misalignment of the motor shaft due to the influence of magnetic force.

According to the present invention, it is possible to provide a transaxle that can suppress the occurrence of creep while suppressing an increase in cost, and can deal with the problem of difficulty in assembling a bearing.

FIG. 1 is a schematic diagram showing a transaxle according to an embodiment of the present invention. FIG. 2 is an enlarged view showing the vicinity of the housing portion of the transaxle shown in FIG. 1; FIG. 2 is a cross-sectional view showing the size of a groove portion of the transaxle in FIG. 1; FIG. 2 is a reference diagram showing the vicinity of a housing portion of a conventional transaxle.

Hereinafter, a transaxle 10 according to an embodiment of the present invention will be described with reference to the drawings.

A transaxle 10 is provided in the vehicle 1. The vehicle 1 is provided with an engine (not shown) and a battery (not shown). The vehicle 1 is capable of running by using an engine as a power source to drive a first electric motor 20, which will be described later, and by driving a second electric motor 30, which will be described later, by driving the first electric motor 20.The vehicle 1 can also run by stopping the engine and turning off the battery. The vehicle is a so-called series hybrid vehicle that is capable of running (EV running) by driving the second electric motor 30 using the second electric motor 30 as a power source.

In addition, although the transaxle 10 used for a hybrid vehicle was shown as an example in this embodiment, the transaxle of the present invention is not limited to a hybrid vehicle, but can also be suitably used as a transaxle for an electric vehicle. .

In the following description, the direction in which the axis L1 of the first motor shaft 22 and the axis L2 of the second motor shaft 32 of the transaxle 10 extend (axial direction) will be simply referred to as "axial direction X". There is.

In addition, in the following explanation, in the input direction (axial direction (rear) may be described as "rear Rr".

As shown in FIG. 1, the transaxle 10 includes two electric motors 12, a differential mechanism 36, and a transaxle case 40 (case body). Note that among the two electric motors 12, one is a first electric motor 20 that serves as a power generation motor, and the other is a second electric motor 30 that serves as a drive motor.

Further, as shown in FIG. 1, the transaxle 10 is provided with an input shaft 14, a first gear shaft 24 (second shaft body), a second gear shaft 34 (second shaft body), and a plurality of bearings 60. ing. Further, the transaxle case 40 is formed with housing parts 43 and 44 that accommodate the bearing 60.

The first electric motor 20 (MG1) consists of a motor generator. A generator controller including an inverter and the like is connected to the first electric motor 20. The AC power output from the first electric motor 20 is converted into DC power by the generator controller, and the DC power is supplied to the battery, thereby charging the battery. The first electric motor 20 is driven by rotational power transmitted by an engine (not shown).

As shown in FIG. 1, the first electric motor 20 includes a first motor shaft 22 (first shaft body, rotor shaft). The first motor shaft 22 (first shaft body) and the first gear shaft 24 (second shaft body) are connected in series (coaxial) so that the axis L1 coincides with each other, and are spline-fitted. are connected by a

As shown in FIG. 1, the first motor shaft 22 and the first gear shaft 24 are attached to the transaxle case 40 via a bearing 60. For example, the first motor shaft 22 has a motor side bearing 61a (first bearing) attached to the end on the front Fr side, and the motor side bearing 61a is fitted into the housing part 43 and attached to the transaxle case 40. ing. Further, the first gear shaft 24 has a gear side bearing 61b (second bearing) attached to the end on the rear Rr side, and the gear side bearing 61b is fitted into the housing part 43 and attached to the transaxle case 40. ing.

The second electric motor 30 (MG2) consists of a motor generator. A motor controller including an inverter and the like is connected to the second electric motor 30. A battery is connected to the motor controller. The DC power output from the battery is supplied to the motor controller, the DC power is converted to AC power by the motor controller, and the AC power is supplied to the second electric motor 30, thereby driving the second electric motor 30. .

As shown in FIG. 1, the second electric motor 30 includes a second motor shaft 32 (first shaft body, rotor shaft). The second motor shaft 32 (first shaft body) and the second gear shaft 34 (second shaft body) are connected in series (coaxial) so that their axes L2 coincide, and are spline-fitted. are connected by a

As shown in FIG. 1, the second motor shaft 32 and the second gear shaft 34 are attached to the transaxle case 40 via a bearing 60. For example, the second motor shaft 32 has a motor side bearing 62a (first bearing) attached to the end on the front Fr side, and the motor side bearing 62a is fitted into the housing part 44 and attached to the transaxle case 40. ing. Further, the second gear shaft 34 has a gear side bearing 62b (second bearing) attached to the end on the rear Rr side, and the gear side bearing 62b is fitted into the housing part 44 and attached to the transaxle case 40. ing.

In this way, the first gear shaft 24 is coaxially connected to the first motor shaft 22 of the first electric motor 20, and the motor-side bearing 61a is connected to the first motor shaft 22, and the first gear shaft 24 is connected to the first gear shaft 24. A gear side bearing 61b is attached to each of the gear side bearings 61b. Further, a second gear shaft 34 is coaxially connected to the second motor shaft 32 of the second electric motor 30, and the second motor shaft 32 has a motor side bearing 62a, and the second gear shaft 34 has a gear Side bearings 62b are attached to each side.

In the following description, the first motor shaft 22, the first gear shaft 24, the second motor shaft 32, and the second gear shaft 34 may be collectively referred to simply as the "shaft body 16." Further, the motor-side bearings 61a, 62a (first bearings) and the gear-side bearings 61b, 62b (second bearings) may be collectively referred to simply as "bearings 60" for explanation.

The differential mechanism 36 is configured to allow differential movement between a pair of left and right drive shafts (not shown) that drive left and right drive wheels, and to transmit rotational power to the pair of left and right drive shafts. . The power of the second electric motor 30 is transmitted to the differential mechanism 36 via a plurality of gears, and from the differential mechanism 36 to drive wheels (not shown). This causes the drive wheels to rotate and the vehicle 1 to travel.

The transaxle case 40 (case body) serves as a housing body that houses the shaft body 16, various gears, the first electric motor 20, the second electric motor 30, and the like. As shown in FIG. 1, the transaxle case 40 is provided with a partition wall 42 and housing parts 43 and 44.

As shown in FIG. 1, the internal space of the transaxle case 40 is divided by the partition wall 42 into a space on the rear Rr side (a space that becomes a motor room R1) and a space on the front Fr side (a space that becomes a gear room R2). It's partitioned off. As shown in FIG. 1, a first electric motor 20 and a second electric motor 30 are housed in the motor room R1. Moreover, the first gear shaft 24, the second gear shaft 34, and various gears are accommodated in the gear chamber R2.

Housing parts 43 and 44 are provided to accommodate bearing 60. As shown in FIG. 1, the housing parts 43 and 44 are formed on the partition wall 42.

As shown in FIG. 1, the transaxle 10 includes a housing portion 43 (a housing portion on the first motor 20 side) in which the motor side bearing 61a of the first motor shaft 22 and the gear side bearing 61b of the first gear shaft 24 are housed. ), and a housing part 44 (housing part on the second electric motor 30 side) in which the motor side bearing 62a of the second motor shaft 32 and the gear side bearing 62b of the second gear shaft 34 are housed. In the following description, the housing portion 44 on the second electric motor 30 side will be described, and detailed description of the housing portion 43 on the first electric motor 20 side will be omitted.

The housing portion 44 is provided to accommodate a motor-side bearing 62a (first bearing) and a gear-side bearing 62b (second bearing). As shown in FIG. 2, the housing part 44 is provided with two fitting parts 46 and a groove part 48. Further, the housing portion 44 is formed with an insertion hole 45 (a through hole penetrating in the axial direction X) into which the second motor shaft 32 and the second gear shaft 34 are inserted.

The fitting portion 46 is provided for fitting the bearing 60 therein. As described above, the housing portion 44 is provided with two fitting portions 46 . More specifically, as shown in FIG. 2, the housing portion 44 is provided with fitting portions 46 on the rear Rr side and the front Fr side, respectively. Further, one of the two fitting portions 46 (on the rear Rr side) is a first fitting portion 46a into which a motor side bearing 62a (first bearing) is fitted. Further, the other of the two fitting portions 46 (front Fr side) is a second fitting portion 46b into which a gear side bearing 62b (second bearing) is fitted.

The groove portion 48 is formed as a groove in the housing portion 44 . The groove portion 48 is formed in an annular shape on the inner circumferential surface 45a of the housing portion 44 (the inner circumferential surface of the insertion hole 45). As shown in FIG. 2, the groove portion 48 is formed to be depressed toward the outer circumferential direction from the inner circumferential surface 45a of the housing portion 44, and has a predetermined depth. Moreover, the groove part 48 is formed in an annular shape so as to go around the inner peripheral surface. In the transaxle 10 of this embodiment, the groove portion 48 has approximately the same depth D1 and approximately the same width D2 at any position on the inner circumferential surface of the housing portion 44 (see FIG. 3(a)). .

Further, in the transaxle 10 of this embodiment, as shown in FIG. 3(a), the groove portion 48 is a groove having a U-shaped cross section. It is advantageous that the groove portion 48 has a U-shaped cross-sectional shape in that processing when forming the groove portion 48 is easy. In the transaxle 10 of this embodiment, an example is shown in which the groove portion 48 has a substantially U-shaped cross-sectional shape, but the transaxle of the present invention is not limited to this embodiment. For example, the cross-sectional shape of the groove portion can be appropriately selected from a circular arc shape (semi-elliptical shape), a dogleg shape, and the like.

As shown in FIG. 2, the groove portion 48 is formed at a position between the two fitting portions 46. To explain in more detail, the groove portion 48 is located at an intermediate position in the housing portion 44 in the axial direction X of the second motor 30 (the axial direction of the second motor shaft 32), and is located between the first fitting portion 46a and the second fitting portion It is formed between the recessed portion 46b.

<About assembly>
Next, a procedure for assembling the bearings 60 (motor side bearing 62a and gear side bearing 62b), shaft body 16 (second motor shaft 32 and second gear shaft 34), etc. to the transaxle case 40 will be described.

In the transaxle 10, after the motor side bearing 62a and the second motor shaft 32 are assembled, the gear side bearing 62b and the second gear shaft 34 are assembled. To explain in more detail, first, the motor-side bearing 62a is press-fitted into the first fitting part 46a so that the outer ring contacts the first fitting part 46a (outer diameter press-fitting). Next, the second motor shaft 32 is advanced from the rear Rr side to the front Fr side, and is inserted into the inside (inner ring) of the motor side bearing 62a. That is, on the second motor shaft 32 side, the motor side bearing 62a is press-fitted into the housing part 44 (first fitting part 46a), and the second motor shaft 32 and the motor side bearing 62a are It is a gap fit.

Next, the second gear shaft 34 is attached to the inner ring of the gear side bearing 62b by press fitting, and the unit of the gear side bearing 62b and the second gear shaft 34 is attached to the housing portion 44 by entering from the front Fr side to the rear Rr side. That is, on the second gear shaft 34 side, the second gear shaft 34 is attached to the gear side bearing 62b by press fit (inner diameter press fit), and the gear side bearing 62b and the housing part 44 (second fitting part 46b) are It is a gap fit.

As described above, in the transaxle 10 of the present embodiment, the motor side bearing 62a (first bearing) has an outer ring press-fitted into the housing part 44, and the second motor shaft 32 (first shaft body) is fitted into the motor side bearing 62a with a clearance fit.

That is, in the transaxle 10 of this embodiment, the housing part 44 is provided with the groove part 48, and in the process of assembling the transaxle 10 (the process of manufacturing the transaxle 10), the motor side bearing 62a (first bearing) is attached. an outer diameter press-fitting step of press-fitting into the housing portion 44; a first-shaft clearance fitting step of fitting the second motor shaft 32 (first shaft body) into the motor-side bearing 62a (first bearing) with a clearance fit; After the outer diameter press-fitting step, a second bearing mounting step is included in which the gear side bearing 62b (second bearing) is mounted to the housing portion 44.

Thereby, when assembling the second motor shaft 32, it is possible to assemble the second motor shaft 32 while suppressing misalignment due to the influence of the force during press-fitting and the magnetic field.

To explain in more detail, when attaching a bearing to a shaft body, the inner diameter press-fit method is often used, in which the shaft body is press-fitted into the bearing. It ends up. Therefore, in the transaxle 10 of this embodiment, the bearing 60 (motor side bearing 62a) on the second motor shaft 32 side has an inner ring side in consideration of the influence of the magnetic field, force during press fitting, and suppression of misalignment. The second motor shaft 32 is attached with a clearance fit. Thereby, when assembling the second motor shaft 32, it is possible to suitably assemble the second motor shaft 32 while suppressing misalignment due to force during press-fitting or the influence of a magnetic field.

Further, as described above, in the transaxle 10, the housing portion 44 is provided with the groove portion 48. Therefore, deformation of the housing part 44 when the motor-side bearing 62a is press-fitted into the housing part 44 can be absorbed by the groove part 48, and deformation of the opening of the second fitting part 46b can be suppressed. Thereby, the transaxle 10 of the present embodiment can suppress interference between the gear side bearing 62b and the housing portion 44, and can improve the problem of difficulty in assembling the gear side bearing 62b.

Further, according to the transaxle 10 of this embodiment, it is not necessary to increase the outer diameter of the housing portion 44, and deterioration in durability and strength due to creep can be suppressed. Furthermore, according to the transaxle 10 of the present embodiment, the occurrence of creep can be suppressed without increasing the outer diameter of the housing portion 44, so it is not necessary to provide an O-ring or the like as a countermeasure against creep. I don't. Therefore, it is possible to suppress deterioration in durability and strength due to creep while suppressing an increase in cost.

Furthermore, in the transaxle 10, the groove portion 48 can function as an oil reservoir. This can be expected to improve lubrication, especially for the bearing 60 where oil shortage is a concern. To explain in more detail, when the rotation of the electric motor 12 decreases or stops, there is a concern that oil may decrease between the bearings. In contrast, in the transaxle 10 of this embodiment, the groove portion 48 functions as an oil reservoir. As a result, improved lubrication of the bearing can be expected.

Note that the transaxle of the present invention may have an oil hole provided in the shaft body. For example, an oil hole may be provided in the peripheral wall of the second motor shaft 32 near the position where the groove portion 48 is provided. With such a configuration, the oil passing inside the second motor shaft 32 is scattered in the circumferential direction of the second motor shaft 32 when the rotation speed of the second electric motor 30 is high, and the oil reaches the groove portion 48. , when the rotational speed of the second electric motor 30 is low (when the amount of oil splashed is reduced and the oil is difficult to reach), oil can be supplied from the groove 48 to the bearing 60. As a result, a further lubrication effect on the bearing can be expected.

Furthermore, in the transaxle 10 of the present embodiment, by providing the groove portion 48, the housing portion 44 can be easily elastically deformed, and generation of abnormal noise due to eccentric rotation of the shaft body 16 can be suppressed.

To explain in more detail, the shaft body constituted by the two shaft bodies 16 (for example, the second motor shaft 32 and the second gear shaft 34) is designed to avoid the gap between the bearing 60 and the transaxle case 40 or between the shaft bodies. There are slight gaps in various places, such as the splines. Therefore, it is difficult for the shaft unit to be configured as a completely straight shaft, and a slight inclination occurs. Furthermore, if the inclination of the shaft unit becomes large, it rotates eccentrically in a dogleg shape, which may generate abnormal noise.

Here, in the transaxle 10 of the present embodiment, the groove portion 48 provided in the portion (between the first fitting portion 46a and the second fitting portion 46b of the housing portion 44) that bears the load due to the rotation of the shaft body is , functions as a buffer part. This makes it possible to absorb the eccentric rotation of the two shaft bodies 16 (the second motor shaft 32 and the second gear shaft 34) in a dogleg shape. As a result, the effect of suppressing abnormal noise that occurs when the shaft body rotates in an inclined state can be expected.

Furthermore, in the transaxle 10 of this embodiment, the groove portion 48 is formed in an annular shape on the inner circumferential surface of the housing portion 44 . Thereby, it is possible to suppress unevenness in the deformation suppressing effect of the housing portion 44. That is, when the motor-side bearing 62a is press-fitted into the housing portion 44, the deformation of the housing portion 44 can be absorbed by the groove portion 48 substantially uniformly in the circumferential direction.

Here, when considering the size of the groove part 48, it was found that when the depth (radial depth D1) of the groove part 48 is larger than the width direction size (gap width D2 of the groove part 48), the housing part 48 It was found that the effect of suppressing deformation is high.

Therefore, it is desirable that the groove portion 48 has a predetermined depth. For example, as shown in FIG. 3(a), the depth D1 of the groove portion 48 is preferably larger than the width dimension (gap width D2). Thereby, the effect of suppressing deformation of the housing portion 44 can be enhanced.

The depth D1 and gap width D2 of the groove portion 48 can be set according to the diameter D5 of the inner circumferential surface 45a and the opening diameter D4 of the fitting portion 46 (the diameter of the bearing 60). Specifically, the depth D1 of the groove 48 can be increased by making the diameter D5 of the inner peripheral surface 45a larger than the diameter D3 of the deepest part of the groove 48. Further, the depth D1 of the groove portion 48 can be set according to the opening diameter D4 of the fitting portion 46 (the diameter of the bearing 60).

Note that the groove portion 48 is more easily bent as the depth D1 is increased, and the effect of suppressing deformation of the housing portion 44 is increased. Moreover, in addition to increasing the depth D1 of the groove portion 48, the effect of suppressing deformation of the housing portion 44 can be obtained by increasing the gap width D2. For example, as shown in FIG. 3(b), the groove portion 48 may have a large gap width D2a. That is, by making the groove portion 48 large in both depth D1 and gap width D2, the effect of suppressing deformation of the housing portion 44 can be obtained.

Although the transaxle 10 according to the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

For example, in the transaxle 10 according to the above-described embodiment, an example was shown in which the groove portion 48 was provided in the housing portion 44 into which the second motor shaft 32 of the second electric motor 30 is inserted, but the present invention is not limited to the above-described embodiment. Not limited. Specifically, in the transaxle of the present invention, a groove may be provided in the housing portion 43 to which the first motor shaft 22 of the first electric motor 20 (MG1) is attached, and to which the input shaft 14 is attached. The housing portion may be provided with a groove portion.

The present invention is not limited to the embodiments shown above, but may have other embodiments within the teaching and spirit of the invention without departing from the scope of the claims. The components of the embodiments described above may be arbitrarily selected and combined. Further, any component of the embodiment and any component described in the means for solving the invention or a component that embodies any component described in the means for solving the invention may be arbitrarily combined. It may be configured as follows.

INDUSTRIAL APPLICATION This invention can be suitably adopted as a transaxle of vehicles, such as a hybrid vehicle and an electric vehicle.

10 Transaxle 12 Electric motor 16 Shaft body 20 First electric motor (electric motor)
22 First motor shaft (first shaft body)
24 First gear shaft (second shaft body)
30 Second electric motor (electric motor)
32 Second motor shaft (first shaft body)
34 Second gear shaft (second shaft body)
40 Transaxle case (case body)
43 Housing part 44 Housing part 46a First fitting part 46b Second fitting part 48 Groove part 60 Bearing 61a Motor side bearing (first bearing, bearing)
61b Gear side bearing (second bearing, bearing)
62a Motor side bearing (first bearing, bearing)
62b Gear side bearing (second bearing, bearing)
D1 Depth D2 Gap width

Claims (2)

A transaxle comprising at least one electric motor, at least two shaft bodies connected in series, and a case body housing the electric motor and the shaft body,
Of the two shafts, when the shaft on the motor side is the first shaft and the other is the second shaft,
a first bearing attached to the first shaft;
a second bearing attached to the second shaft;
a housing part formed in the case body and housing the first bearing and the second bearing;
The housing part includes:
a first fitting portion into which the first bearing is fitted;
a second fitting part into which the second bearing is fitted;
a groove portion formed as a groove in the housing portion;
The groove portion is formed on the inner peripheral surface of the housing portion and expands toward the axis of the first bearing and the second bearing between the first fitting portion and the second fitting portion. The portion formed to protrude is formed to have a predetermined depth from the inner circumferential surface ,
A transaxle , wherein the depth of the groove is greater than the width . The transaxle according to claim 1, wherein the groove portion is formed in an annular shape on the inner circumferential surface of the housing portion.

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