CN106143115B

CN106143115B - Electric automobile and in-wheel motor driving system

Info

Publication number: CN106143115B
Application number: CN201510127877.1A
Authority: CN
Inventors: 张小林; 章俊杰
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2015-03-23
Filing date: 2015-03-23
Publication date: 2021-03-09
Anticipated expiration: 2035-03-23
Also published as: CN106143115A

Abstract

The invention relates to an electric vehicle and an in-wheel motor drive system. The in-wheel motor drive system includes a hub-side rotary member connected to the hub, a support shaft connected to the axle, the support shaft being coupled to the hub-side rotary member, a housing, and a housing rear cover. The shell and the shell rear cover define a motor cavity for mounting a motor, and the shell and the support shaft define a reducer cavity for mounting a reducer. The in-wheel motor driving system further comprises a pressure balancing device, a motor cavity opening and/or a speed reducer cavity opening are/is formed in the shell, the pressure balancing device is respectively communicated with the corresponding cavities through the motor cavity opening and/or the speed reducer cavity opening, and gas can respectively enter and exit the corresponding cavities from the pressure balancing device. The pressure balancing device can balance the internal and external pressures of the motor cavity and/or the speed reducer cavity when the temperature changes in the working process.

Description

Electric automobile and in-wheel motor driving system

Technical Field

The invention relates to an electric automobile, in particular to an in-wheel motor driving system of the electric automobile.

Background

With the development of electric vehicles, in-wheel motor drive systems have been developed. The in-wheel motor driving system is a motor built in a wheel, can independently control each wheel, has high power transmission efficiency and responsiveness, and does not need parts such as a transmission shaft, a differential gear and the like. Therefore, the in-wheel motor drive system not only improves the degree of freedom in vehicle body design, but also can increase the in-vehicle space.

Fig. 1 shows an example of a prior art in-wheel motor drive system. As shown in fig. 1, the in-wheel motor drive system includes a hub-side rotating member 100 'connected to a hub (not shown), a support shaft 200' connected to an axle (not shown), a housing 300 ', and a housing rear cover 400'. The hub-side rotating member 100' is fixedly connected to the axle, and a hub bearing (not shown) is mounted on the radially inner side thereof. The support shaft 200 'is coupled to the hub-side rotating member 100' and connected to an output of the motor rotor through a reducer, and an outer side (left side in the drawing) thereof is connected to a rim (not shown in the drawing). The case 300 ' and the case back cover 400 ' define a motor chamber 1 ' for mounting the motor, the case 300 ' and the support shaft 200 ' define a decelerator chamber 2 ' for mounting the decelerator, and the decelerator chamber 2 ' is filled with oil for lubricating the decelerator gears. The housing rear cover 400 'and the hub-side rotary member 100' also define a space for mounting the wheel brake. In the in-wheel motor driving system, a first decelerator oil seal 20 ' and a second decelerator oil seal 40 ' are provided between a housing 300 ' and a support shaft 200 ', a motor chamber 1 ' and a decelerator chamber 2 ' are sealed by a motor decelerator oil seal 50 ', and a housing rear cover 400 ' is hermetically connected to the housing 300 ' by a first motor oil seal 60 ' and a second motor oil seal 70 '. In fig. 1, the second motor oil seal 70' is in the form of an O-ring.

During the operation of the in-wheel motor driving system, the oil-gas pressure in the reducer chamber 2' changes due to thermal expansion and contraction. In order to balance the air pressure in the decelerator chamber 2 'to protect the first and second decelerator oil seals 20', 40 'and the motor decelerator oil seal 50' from thermal fatigue, an opening communicating with the decelerator chamber 2 'is provided in the housing 300' near the support shaft 200 ', and a breather valve 10' is installed in the opening. In this way, when the gas pressure inside the decelerator chamber 2 'is excessive due to the temperature increase, the gas can be discharged to the outside through the vent valve 10'. However, when the gas pressure decreases due to a decrease in temperature, the gas pressure in the retarder chamber 2' cannot be kept in equilibrium.

Moreover, in actual conditions, the in-wheel motor drive system needs to meet the waterproof standard above IP 6. In this case, the entire wheel will be submerged in the water for a period of time. When the water level is higher than the vent valve 10 ', water will flow into the retarder chamber 2 ', which will cause damage to the first and second retarder oil seals 20 ', 40 ' and the motor retarder oil seal 50 ' and thus corrode the retarder.

In addition, the motor chamber 1 ' is always in a sealed state, and when the temperature rises, the internal pressure of the motor chamber 1 ' will be higher than the external pressure, thereby generating pressure to the first and second motor oil seals 60 ', 70 ' and the motor reducer oil seal 50 ', which forces gas to flow into the reducer chamber 2 ' or to the outside, and shortening the service life of the first and second motor oil seals 60 ', 70 ' and the motor reducer oil seal 50 '. On the other hand, when the temperature suddenly decreases, the external pressure of the motor chamber 1 'will be higher than the internal pressure, thereby generating pressure to the first and second motor oil seals 60', 70 'and the motor reducer oil seal 50', which forces external air or water to flow into the motor chamber 1 ', and shortens the service life of the first and second motor oil seals 60', 70 'and the motor reducer oil seal 50'.

All of which can cause damage to the in-wheel motor drive system. Accordingly, there is a need for an improved in-wheel motor drive system.

Disclosure of Invention

In a first aspect, the present invention provides an in-wheel motor drive system including a hub-side rotating member, a support shaft, a housing, and a case back cover, the hub-side rotating member being connected to a hub, the support shaft being connected to an axle, the support shaft being coupled to the hub-side rotating member. The shell and the shell rear cover define a motor cavity for mounting a motor, and the shell and the support shaft define a reducer cavity for mounting a reducer. The difference from the in-wheel motor driving system of the prior art shown in fig. 1 is that the in-wheel motor driving system of the present invention further includes a pressure balancing device, a motor chamber opening and/or a reducer chamber opening is provided on the housing, the pressure balancing device is respectively communicated with the corresponding chambers through the motor chamber opening and/or the reducer chamber opening, and gas can respectively enter and exit the corresponding chambers from the pressure balancing device.

According to the present invention, the rest of the in-wheel motor drive system is sealed except for the motor chamber opening and/or the retarder chamber opening.

Preferably, the pressure equalisation means is mounted on the housing to maintain pressure equalisation of the motor chamber and/or the retarder chamber under operating conditions.

According to an embodiment of the invention, a circumferential groove is provided on the outer surface of the housing, the pressure equalizing device being fitted in the circumferential groove. Preferably, the pressure balancing device is fixed in the circumferential groove by a bead.

The pressure compensation device is designed as a closed hollow structure, for example like a bicycle inner tube. Preferably, the pressure equalizing device is made of a deformable material, for example a flexible rubber material. In this way, gas can freely flow into and out of the motor chamber and/or the retarder chamber.

Preferably, the pressure equalizing device is filled with a gas under pressure in an initial state. The pressure is less than the maximum possible gas pressure in the motor chamber and the retarder chamber, and may be determined by the thermal expansion of the gas in the retarder chamber and the motor chamber from normal temperature to maximum temperature.

According to an embodiment of the invention, the pressure balancing means comprises a motor pressure balancing means and a retarder pressure balancing means separated from each other and communicating with the motor chamber opening and the retarder chamber opening, respectively. Preferably, the motor pressure compensation device and the reduction gear pressure compensation device are each configured in the form of a semi-ring. In this way, motor pressure balance device and reduction gear pressure balance device can design alone, prevents that the oil gas in the reduction gear cavity from flowing into the motor cavity.

According to the invention, the motor pressure balancing device forms the motor chamber as a relatively closed unit, which relatively isolates the motor chamber from the outside. Likewise, the retarder pressure equalization means makes the retarder chamber a relatively closed unit, which relatively isolates the retarder chamber from the outside. Also, the motor pressure balancing device can ensure a normal pressure in the motor chamber regardless of a temperature rise or fall in the in-wheel motor drive system. Under the condition of no internal and external pressure difference, the compression requirement on the motor oil seal is reduced, and the service life of the motor oil seal is effectively prolonged. Also, the retarder pressure equalizing device can ensure normal pressure in the retarder chamber regardless of temperature rise or fall in the in-wheel motor drive system. Under the condition of no internal and external pressure difference, the compression requirement on the oil seal of the speed reducer is reduced, and the service life of the oil seal of the speed reducer is effectively prolonged.

Therefore, the motor pressure balancing device relatively isolates the motor space (including the motor chamber and the motor pressure balancing device) from the outside, and protects components in the motor chamber from damage due to external corrosion. Also, the retarder pressure equalization means relatively isolates the retarder space (including the retarder chamber and the retarder pressure equalization means) from the outside, protecting the components within the retarder chamber from damage due to external corrosion.

In a second aspect, the present invention provides an electric vehicle including the in-wheel motor drive system described above.

The in-wheel motor drive system of the invention has the following advantages.

1. Can design motor pressure balancing unit and reduction gear pressure balancing unit alone, effectively prevent that the interior oil gas of reduction gear cavity from flowing into the motor cavity and leading to motor corrosion damage.

2. The motor pressure balancing device and the reducer pressure balancing device do not need to change the layout and the installation arrangement of the existing in-wheel motor driving system, and the axial space of the in-wheel motor driving system is not increased.

3. The motor pressure balancing device and the reducer pressure balancing device have simple structures, low cost and easy installation and replacement.

Drawings

These and other aspects and advantages of the present invention will be apparent to and understood by those skilled in the art from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings. In the figure:

fig. 1 is a partial cross-sectional view of a prior art in-wheel motor drive system without a pressure balancing device.

Fig. 2 is a plan view of the in-wheel motor drive system with a pressure balancing device of the present invention.

Fig. 3 is a cross-sectional view taken along line Z2-Z2 of fig. 2.

Fig. 4 is a cross-sectional view taken along line Z3-Z3 of fig. 2.

List of reference numerals

1' Motor Chamber

2' speed reducer chamber

10' vent valve

20' first speed reducer oil seal

40' second reducer oil seal

50' motor reducer oil seal

60' first motor oil seal

70' second motor oil seal

100' hub-side rotating member

200' support shaft

300' outer casing

400' rear cover of shell

1 Motor Chamber

2 speed reducer chamber

Pressure balancing device of 3 speed reducer

4 motor pressure balancing device

5 motor cavity opening

6 reducer cavity opening

20 first speed reducer oil seal

40 second reducer oil seal

50 motor reducer oil seal

60 first motor oil seal

70 second motor oil seal

100 hub side rotating member

200 support shaft

300 outer casing

400 casing back cover

Detailed Description

In the following detailed description of exemplary embodiments, various features and aspects of the present invention will be described with reference to fig. 2-4.

Fig. 2 shows an in-wheel motor drive system according to an embodiment of the present invention, which has a reducer pressure equalizing device 3 and a motor pressure equalizing device 4. Both pressure equalising means 3 and 4 are hollow structures made of flexible rubber, similar to bicycle inner tubes. A motor chamber opening 5 and a reducer chamber opening 6 are provided on the housing 300, and are respectively communicated with the motor chamber 1 and the reducer chamber 2. In this example, the pressure-equalizing

devices

3 and 4 are each configured in a semi-annular shape, and a circumferential groove is provided on the outer surface of the housing 300 for mounting the pressure-equalizing

devices

3 and 4.

Fig. 3 shows a sectional view along the line Z2-Z2 of fig. 2, in which the retarder pressure equalizing device 3 is shown. As shown in fig. 3, the in-wheel motor drive system includes a hub-side rotating member 100 connected to a hub (not shown), a support shaft 200 connected to an axle (not shown), a housing 300, and a housing rear cover 400. The hub-side rotating member 100 is fixedly connected to the axle, and a hub bearing (not shown) is mounted radially inward thereof. The support shaft 200 is coupled to the hub-side rotating member 100 and connected to an output of the motor rotor through a speed reducer, and an outer side (left side in the drawing) thereof is connected to a rim (not shown in the drawing). The housing 300 and the case back cover 400 define a motor chamber 1 for mounting the motor, the housing 300 and the support shaft 200 define a decelerator chamber 2 for mounting the decelerator, and the decelerator chamber 2 is filled with oil for lubricating the decelerator gears. The housing back cover 400 and the hub-side rotating member 100 also define a space for mounting a wheel brake. In the in-wheel motor driving system, a first decelerator oil seal 20 and a second decelerator oil seal 40 are provided between a housing 300 and a support shaft 200, a motor chamber 1 and a decelerator chamber 2 are sealed by a motor decelerator oil seal 50, and a housing rear cover 400 is hermetically connected to the housing 300 by a first motor oil seal 60 and a second motor oil seal 70. In this example, the second motor oil seal 70 is in the form of an O-ring.

In fig. 3, the retarder chamber 2 communicates with the retarder pressure equalization means 3 via the retarder chamber opening 6. The retarder pressure equalization means 3 ensure that the retarder chamber 2 is sealed against the outside. In the initial phase, the retarder pressure equalization device 3 is filled with a gas at a pressure which is less than the maximum possible pressure in the retarder chamber 2 and which is determined by the thermal expansion of the gas in the retarder chamber 2 from the normal temperature to the maximum temperature. When the temperature in the retarder chamber 2 rises, the gas thermally expands and the gas in the retarder chamber 2 flows through the retarder chamber opening 6 to the retarder pressure balancing device 3, thereby balancing the pressure in the retarder chamber 2 (because the retarder pressure balancing device 3 is made of a flexible material, the pressure variations of the retarder pressure balancing device 3 are negligible). On the other hand, when the temperature in the retarder chamber 2 drops, the gas contracts and the gas in the retarder pressure balancing device 3 flows through the retarder chamber opening 6 to the retarder chamber 2, thereby balancing the pressure in the retarder chamber 2.

Fig. 4 shows a cross-sectional view along line Z3-Z3 of fig. 2, in which the motor pressure balancing device 4 is shown.

In fig. 4, the motor chamber 1 communicates with the motor pressure balancing device 4 via a motor chamber opening 5. The motor pressure balancing device 4 ensures that the motor chamber 1 is sealed against the outside. Similarly, in the initial phase, the motor pressure balancing device 4 is filled with a gas at a pressure that is less than the maximum possible pressure in the motor chamber 1 and is determined by the thermal expansion of the gas in the motor chamber 1 from the normal temperature to the maximum temperature. When the temperature in the motor chamber 1 rises, the gas thermally expands and the gas in the motor chamber 1 flows through the motor chamber opening 5 to the motor pressure balancing means 4, thereby balancing the pressure in the motor chamber 1 (since the motor pressure balancing means 4 is made of a flexible material, the pressure variations of the motor pressure balancing means 4 are negligible). On the other hand, when the temperature in the motor chamber 1 drops, the gas contracts and the gas in the motor pressure balancing device 4 flows through the motor chamber opening 5 to the motor chamber 1, thereby balancing the pressure in the motor chamber 1.

The invention has been described above with reference to illustrative embodiments. However, other modifications and alterations will occur to others upon reading and understanding the specification and the annexed drawings. The invention is therefore not limited to the embodiments described above, but may be modified and varied within the scope of the claims. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. The in-wheel motor driving system is characterized in that the in-wheel motor driving system further comprises a pressure balancing device, a motor cavity opening and/or a speed reducer cavity opening are formed in the shell, the pressure balancing device is respectively communicated with corresponding cavities through the motor cavity opening and/or the speed reducer cavity opening, gas can enter and exit the corresponding cavities from the pressure balancing device respectively, and the pressure balancing device is of a closed hollow structure.

2. The in-wheel motor drive system according to claim 1, wherein a circumferential groove is provided on an outer surface of the housing, and the pressure equalizing device is fitted in the circumferential groove.

3. The in-wheel motor drive system according to claim 2, wherein the pressure balancing device is fixed in the circumferential groove by a bead.

4. The in-wheel motor drive system according to claim 1, wherein the pressure equalizing device is made of a deformable material.

5. The in-wheel motor drive system according to claim 1, wherein the pressure balancing means is filled with a gas of a certain pressure in an initial state.

6. An in-wheel motor drive system according to any one of claims 1 to 5, wherein the pressure equalizing device includes a motor pressure equalizing device and a decelerator pressure equalizing device that are separate from each other, and that communicate with the motor chamber opening and the decelerator chamber opening, respectively.

7. The in-wheel motor drive system according to claim 6, wherein the motor pressure equalizing device and the reducer pressure equalizing device are each configured in a semi-annular shape.

8. An electric vehicle characterized by comprising the in-wheel motor drive system according to any one of claims 1 to 7.