JP2022095217A - Lubrication device of transmission for electric vehicle - Google Patents

Abstract

To provide a lubrication device of a transmission for an electric vehicle which achieves improvement of lubricity of a splined part between an output shaft of an electric motor and an input shaft of the transmission.SOLUTION: A lubrication device of a transmission for an electric vehicle comprises: a motor 10 which generates a driving force of an electric vehicle; a transmission mechanism 20 connected to the motor 10; a motor output shaft 11 of the motor 10 which outputs the driving force of the motor 10 to the transmission mechanism 20; an input shaft 22 which is splined to the motor output shaft 11 and inputs the driving force to the transmission mechanism 20; and a lubrication oil guide ring 50 which supplies a lubrication oil to a splined portion between the motor output shaft 11 and the input shaft 22. The lubrication oil guide ring 50 has lubrication oil guide vanes 52 each of which is formed into a spiral shape extending from the outer periphery side toward the inner periphery side along a normal rotation direction of the splined portion at the radial outer side of the splined portion in a housing 21 of the transmission mechanism 20.SELECTED DRAWING: Figure 3

Description

The present invention relates to a lubrication device for a transmission for an electric vehicle.

In recent years, from the viewpoint of reducing the environmental load, in the field of commercial vehicles such as trucks, electric trucks that are not equipped with an internal combustion engine and are driven only by an electric motor have been developed. As a drive unit of such an electric vehicle, for example, an electric motor and a power transmission mechanism such as a transmission or a differential composed of a plurality of gears are provided, and the driving force of the motor is transmitted to the differential gear to which the drive wheels are connected. Is known (see Patent Document 1).

International Publication No. 2014/148410

The drive unit of the electric vehicle described above is provided with an input shaft of a transmission connected to the output shaft of the electric motor in order to receive the driving force from the electric motor, and the output shaft of the electric motor and the input shaft of the transmission are respectively. Splines are formed and combined. Since the electric motor rotates at high speed, lubrication of the spline coupling portion is very important.

The present invention has been made to solve such a problem, and provides a lubrication device for a transmission for an electric vehicle that improves the lubricity of a spline coupling portion between an output shaft of an electric motor and an input shaft of the transmission. It is a thing.

The present invention has been made to solve such a problem, and can be realized as the following aspects or application examples.

The lubrication device for the transmission for an electric vehicle according to this application example outputs the driving force of the electric motor to the transmission, the electric motor for generating the driving force of the electric vehicle, the transmission connected to the electric motor, and the driving force of the electric motor. Spline coupling between the output shaft of the electric motor, the input shaft of the transmission that is spline-coupled to the output shaft of the electric motor and inputs the driving force to the transmission, and the output shaft of the electric motor and the input shaft of the transmission. It is a lubricating device for a transmission for an electric vehicle composed of a lubricating oil guide portion for guiding lubricating oil to a portion, and the lubricating oil guide portion is the diameter of the spline coupling portion in the casing of the transmission. It is characterized by having a guide vane of lubricating oil formed in a vortex shape approaching from the outer peripheral side to the inner peripheral side along the forward rotation direction of the spline coupling portion on the outer side of the direction.

According to the above configuration, since the guide blades of the lubricating oil are provided on the outer periphery of the output shaft of the spline-coupled electric motor and the input shaft of the transmission, the lubricating oil is provided from the outside of the shaft in the axial direction as the shaft rotates. The lubricating oil is guided, and the lubricating oil is reliably supplied by the spline joint portion. This makes it possible to improve the lubricity of the spline coupling portion between the output shaft of the electric motor and the input shaft of the transmission.

It is a schematic top view of the electric truck provided with the breather device of the drive mechanism in one Embodiment of this invention. It is a plan sectional view of the drive unit of a vehicle. It is a vertical sectional view along the AA line along the axial direction of the input shaft of FIG. It is a perspective view of the lubricating oil guide ring. It is a vertical sectional view along the BB line perpendicular to the axis of the input shaft of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic top view of an electric truck provided with a vehicle drive device according to an embodiment of the present invention.

As shown in FIG. 1, the vehicle 1 according to the present embodiment is an electric truck including a ladder frame 2, a cab 3, a wheel mechanism 4, and a drive unit 5 (drive mechanism).

The ladder frame 2 has a pair of left and right side frames 2a and a plurality of cross members 2b. The side frames 2a extend along the vehicle front-rear direction of the vehicle 1 and are arranged parallel to each other in the vehicle width direction. The plurality of cross members 2b extend in the vehicle width direction and connect a pair of side frames 2a. The ladder frame 2 supports the cab 3, the drive unit 5, and other heavy objects mounted on the vehicle 1.

The cab 3 is a structure including a driver's seat (not shown), and is provided above the front portion of the ladder frame 2.

The wheel mechanism 4 is located at the rear of the vehicle and has two rear wheels 4a arranged on the left and right sides, and a pair of left and right rear axles 4b as axles of the rear wheels 4a. In the vehicle 1 according to the present embodiment, the driving force is transmitted so that the rear wheels 4a function as the driving wheels, and the vehicle 1 can travel. Although not shown, the wheel mechanism 4 also has front wheels provided at the front of the vehicle.

The drive unit 5 has a motor 10, a speed change mechanism 20, and a differential mechanism 30. The motor 10 generates AC power required for traveling of the vehicle 1 by supplying AC power from a battery (not shown) via an inverter. The speed change mechanism 20 of the present embodiment is a speed reducer, includes a plurality of gears, decelerates the rotational driving force input from the motor 10, and outputs the speed to the differential mechanism 30. The differential mechanism 30 distributes the rotational driving force input from the speed change mechanism 20 to the left and right rear wheels 4a. That is, the drive unit 5 reduces the rotational driving force of the motor 10 to a rotational speed suitable for traveling of the vehicle 1 and transmits it to the rear axle 4b via the speed change mechanism 20 and the differential mechanism 30. As a result, the drive unit 5 rotates the rear wheels 4a via the rear axle 4b to drive the vehicle 1.

Next, FIG. 2 is a plan sectional view of the vehicle drive device of FIG. Hereinafter, the internal structure of the drive unit will be described with reference to the figure.

In the speed change mechanism 20, a plurality of gears are housed in the housing 21. Three shafts, an input shaft 22, an intermediate shaft 23, and an output shaft 24, are rotatably supported in the housing 21. The shafts 22, 23, and 24 extend parallel to each other in the vehicle width direction.

One end of the input shaft 22 is connected to the motor output shaft 11 of the motor 10, and a first gear 25a is provided. The intermediate shaft 23 is provided with a second gear 25b that meshes with the first gear 25a and a third gear 25c. The output shaft 24 is provided with a fourth gear 25d that meshes with the third gear 25c and a fifth gear 25e that meshes with the ring gear 31 of the differential mechanism 30. The diameter of each gear is set so that the reduction ratio required for the speed change mechanism 20 can be realized. The speed change mechanism 20 is configured to be able to convert the rotational driving force of high rotation and low torque input from the motor 10 side into low rotation and high torque and output it.

The differential mechanism 30 distributes the rotational driving force input from the fifth gear 25e, which is the final gear of the transmission mechanism 20, from the ring gear 31 to the pair of left and right differential output shafts 34 via the pinion gear 32 and the side gear 33. .. Each differential output shaft 34 is connected to the rear axle 4b.

Lubricating oil is sealed inside the speed change mechanism 20 and the differential mechanism 30. Here, the amount of lubricating oil enclosed in the speed change mechanism 20 is adjusted so that the vicinity of the lower end portion of each gear becomes the liquid level from the viewpoint of reducing the rotational resistance of each gear. Therefore, in the non-operating state of the drive unit 5, the lubricating oil is not supplied to the input shaft 22 of the speed change mechanism 20. However, in the drive unit 5 of the present embodiment, when the drive unit 5 operates and each gear rotates, the lubricating oil is scraped up and each component is lubricated. As a result, in the drive unit 5 of the present embodiment, lubricating oil can be supplied from the inside of the input shaft 22 to the coupling portion between the motor output shaft 11 of the motor 10 and the input shaft 22 of the speed change mechanism 20.

Specifically, FIG. 3 shows a vertical cross-sectional view along the line AA along the axial direction of the input shaft of FIG. 2, FIG. 4 shows a perspective view of the lubricating oil guide ring, and FIG. 5 shows FIG. A vertical cross-sectional view is shown along the BB line perpendicular to the axis of the input shaft. The configuration and action / effect will be described. In addition, in FIGS. 3 and 5, in consideration of the legibility of the drawings, the configurations other than the main parts are omitted.

The motor 10 has a stator and a rotor (not shown) in the motor case 12, and a motor output shaft 11 connected to the rotor protrudes from the motor case 12.

In FIG. 3, the tip portion of the motor output shaft 11 is shown, and the tip portion of the motor output shaft 11 is rotatably supported by the motor case 12 via a bearing 13. Further, the motor output shaft 11 is provided with a sealing material 14 between the motor case 12 and the motor case 12 on the tip side of the portion supported by the bearing 13, and the motor case 12 and the housing 21 of the speed change mechanism 20 are provided with each other. The space is partitioned. The tip portion of the motor output shaft 11 has a cylindrical shape, and internal teeth 11a spline-bonded to the tip portion of the motor output shaft 11 are formed on the inner circumference.

The input shaft 22 of the speed change mechanism 20 has external teeth 22a splined with the internal teeth 11a of the tip portion of the motor output shaft 11 formed on the outer periphery of the tip on the right side in the vehicle width direction. The input shaft 22 is rotatably supported by bearings 40 and 41 at the left side portion of the outer teeth 22a in the vehicle width direction (center side in the rotation axis direction) and the left end portion in the vehicle width direction, respectively. A sealing material is provided on these bearings 40 and 41 to prevent lubricating oil from passing through.

Further, the input shaft 22 is internally formed with a through hole 22b penetrating in the axial direction, and lubricating oil flows from the left side to the right end of the input shaft 22 in the vehicle width direction through the through hole 22b, and the input shaft 22 and the motor. Lubricating oil can be supplied to the spline coupling portion with the output shaft 11.

Further, an annular lubricating oil guide ring 50 (lubricating oil guide portion) for supplying lubricating oil to the spline coupling portion is provided on the radial outer side of the spline coupling portion between the input shaft 22 and the motor output shaft 11. .. The outer circumference of the annular lubricating oil guide ring 50 is fixed to the ring support portion 21a of the housing 21 of the speed change mechanism 20, and the inner circumference and the back surface are fixed to the ring support portion 12a of the motor case 12. The annular lubricating oil guide ring 50 can also be formed on the partition wall of the housing 21 of the speed change mechanism 20.

As shown in FIGS. 4 and 5, the lubricating oil guide ring 50 of the present embodiment has three guide blades 52 formed in the circumferential direction on the front surface (one side surface) of the annular base 51. Each guide blade 52 has a guide surface 52a whose tip is an acute angle while being curved from the inner circumference of the base 51 toward the outer circumference.

As shown in FIG. 5, the guide surface 52a of each guide blade 52 is along the forward rotation direction R (the direction indicated by the white arrow in FIG. 5), which is the rotation direction of the input shaft 22 and the motor output shaft 11 when the vehicle is moving forward. , The shape approaches from the outer peripheral side to the inner peripheral side. That is, the guide surface 52a has a vortex shape along the forward rotation direction of the spline coupling portion. The ring support portion 21a of the housing 21 has an inner circumference along the outer circumference of the lubricating oil guide ring 50, but in the present embodiment, two notched oil flow portions 53a and 53b are formed. Lubricating oil is supplied from the upper oil flow section 53a formed in the ring support portion 21a of the housing 21, and excess lubricating oil is discharged from the lower oil flow section 53b.

As shown by the thick arrow in FIG. 5, the lubricating oil supplied from the upper oil flow section 53a is disturbed and scattered by the rotation of the input shaft 22 and the motor output shaft 11. The scattered lubricating oil hits the inner peripheral surface of the ring support portion 21a of the housing 21 and the guide surface 52a of the guide blade 52, and the airflow generated by the rotation of the input shaft 22 and the motor output shaft 11 and the shape of the guide surface 52a cause the input shaft. It is re-supplied to the spline coupling portion with a centripetal force toward the axial center of 22 and the motor output shaft 11.

As described above, according to the lubrication device of the drive mechanism of the present embodiment, the guide vanes 52 of the lubricating oil are provided on the radial outer side of the motor output shaft 11 of the spline-coupled motor 10 and the input shaft 22 of the transmission mechanism 20. As a result, the lubricating oil is guided from the outside of the shaft in the axial direction as the shaft rotates, and the lubricating oil is reliably supplied by the spline coupling portion. This makes it possible to improve the lubricity of the spline coupling portion between the motor output shaft 11 of the motor 10 and the input shaft 22 of the speed change mechanism 20.

Although the description of the embodiment of the present invention is completed above, the aspect of the present invention is not limited to this embodiment.

For example, in the above embodiment, the lubricating oil guide ring 50 is formed with three guide blades 52, but the number of guide blades and the shape of the guide surface are not limited to this. For example, one, two, or four or more guide blades may be formed, or the guide surface may be a linear surface.

1 Vehicle 4 Wheel mechanism 4a Rear wheel 4b Rear axle 5 Drive unit 10 Motor 11 Motor output shaft 11a Spline engagement output part 12 Motor case 12a Ring support part 20 Speed change mechanism 21 Case body 21a Ring support part 22 Input shaft 23 Intermediate shaft 24 Output shaft 30 Differential mechanism 40, 41 Bearing 50 Lubricating oil guide ring (lubricating oil guide)
51 Base 52 Guide blade 52a Guide surface 53a, 53b Oil flow section

Claims (1)

An electric motor that generates the driving force of an electric vehicle,
The transmission connected to the electric motor and
The output shaft of the electric motor that outputs the driving force of the electric motor to the transmission, and
The input shaft of the transmission, which is spline-coupled to the output shaft of the electric motor and inputs the driving force to the transmission,
A lubricating device for a transmission for an electric vehicle, comprising a lubricating oil guide portion for guiding lubricating oil to a spline coupling portion between the output shaft of the electric motor and the input shaft of the transmission.
The lubricating oil guide portion is formed in a vortex shape that approaches the inner peripheral side from the outer peripheral side along the positive rotation direction of the spline coupling portion on the radial outer side of the spline coupling portion in the casing of the transmission. A lubrication device for a transmission for an electric vehicle, which is characterized by having oil guide blades.

Images