CN115189518A

CN115189518A - Bridge driving system with cooling structure

Info

Publication number: CN115189518A
Application number: CN202110370795.5A
Authority: CN
Inventors: 欧阳鹏; 宋志强; 刘磊
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2022-10-14

Abstract

The invention provides a bridge driving system with a cooling structure, which comprises a motor (M) and a transmission (G) which are connected in an axial direction (A), wherein a motor shaft (S1) of the motor (M) and a transmission shaft (S2) of the transmission (G) are in power connection with each other, the bridge driving system is provided with a cooling liquid flow passage (C) for flowing cooling liquid, the cooling liquid flow passage (C) comprises a motor shaft flow passage (Cs 1) and a transmission shaft flow passage (Cs 2), the motor shaft flow passage (Cs 1) penetrates through the motor shaft (S1) in the axial direction (A), the transmission shaft flow passage (Cs 2) penetrates through the transmission shaft (S2) in the axial direction (A), and the motor shaft flow passage (Cs 1) is communicated with the transmission shaft flow passage (Cs 2). The bridge driving system has good cooling effect.

Description

Bridge driving system with cooling structure

Technical Field

The present invention relates to the field of vehicles, and more particularly to a bridge drive system having a cooling structure.

Background

For electric vehicles, including pure electric vehicles and hybrid (hybrid electric and oil) vehicles, the electric driving modes include central motor driving and hub motor driving. One common arrangement of a central motor drive system is also known as an electric bridge (eexle) drive system.

In order to increase the power density of the bridge drive system, for example, it is possible to control the temperature of the bridge drive system to have a cooling structure without the temperature being too high.

US2012/0153718A1 discloses a heat dissipation system for an electric machine that cools a stator and an inverter of the electric machine using a coolant, and a coolant flow passage surrounds the periphery of the stator. This cooling method does not allow efficient heat dissipation from the output shaft of the motor and the input shaft of the transmission.

US7579725B2 discloses a cooling system for a rotor of an electric machine, in which a cooling fluid channel is formed in the shaft of the machine, the inlet and outlet of the channel being located at the same end of the rotor shaft. This cooling method cannot effectively cool down the entire area of the motor shaft in the axial direction, which makes it impossible to effectively cool down the bearing provided at the end of the motor shaft, for example, which adversely affects the life of the bearing.

Chinese utility model patent CN208180750U discloses a power drive assembly and electric automobile, and the reduction gear setting in this power assembly is between motor and controller, and motor cooling channel sets up the periphery at the motor. Although the motor cooling channel is communicated with the speed reducer cooling channel, the motor shaft cannot be effectively cooled, and the sealing device between the motor and the speed reducer cannot be effectively cooled.

Disclosure of Invention

The present invention is directed to overcome or at least alleviate the above-mentioned disadvantages of the prior art, and to provide a bridge driving system with a cooling structure having a good cooling effect.

The invention provides a bridge drive system with a cooling structure, which comprises a motor and a transmission which are connected in an axial direction, wherein a motor shaft of the motor and a transmission shaft of the transmission are in power connection with each other,

the bridge drive system is provided with a cooling liquid flow passage for flowing cooling liquid, the cooling liquid flow passage comprises a motor shaft flow passage and a transmission shaft flow passage,

the motor shaft flow channel penetrates through the motor shaft in the axial direction, the transmission shaft flow channel penetrates through the transmission shaft in the axial direction, and the motor shaft flow channel is communicated with the transmission shaft flow channel.

In at least one embodiment, the electric machine includes a motor housing portion, the transmission includes a transmission housing portion,

the cooling liquid runner also comprises a motor part runner and a transmission part runner, the motor part runner is formed on the wall of the motor shell part, the transmission part runner is formed on the wall of the transmission shell part, and the motor part runner is communicated with the transmission part runner.

In at least one embodiment, the motor portion flow passage extends in a circumferential direction of the motor while extending in the axial direction.

In at least one embodiment, the bridge drive system further comprises a motor end cap disposed at an end of the motor housing portion distal from the transmission housing portion in the axial direction,

a cover part flow passage is formed in the motor end cover, and two ends of the cover part flow passage are respectively communicated with the motor part flow passage and the motor shaft flow passage.

In at least one embodiment, the transmission shaft flow passage communicates with the transmission portion flow passage.

In at least one embodiment, the transmission section flow passages include a transmission section first flow passage and a transmission section second flow passage respectively located at both ends of the transmission case portion in the axial direction,

the transmission part first flow passage is communicated with the transmission shaft flow passage, and the transmission part second flow passage is communicated with the motor part flow passage.

In at least one embodiment, the coolant flow passage further includes a manifold cavity formed in the transmission case portion, the manifold cavity being located below the internal cavity of the transmission case portion.

In at least one embodiment, the manifold chamber is located at a lowermost portion of the coolant flow channel.

In at least one embodiment, the outlet of the coolant flow channel communicates with the manifold chamber.

In at least one embodiment, the coolant flow passage further includes an inverter flow passage through which an inverter flows, the inverter flow passage being located upstream of the motor shaft flow passage and communicating with an inlet of the coolant flow passage.

The bridge driving system with the cooling structure has good cooling effect.

Drawings

FIG. 1 is a schematic, broken-away schematic diagram of a bridge drive system having a cooling configuration, according to one embodiment of the present invention.

Description of reference numerals:

an M motor; an Mr rotor; an Ms stator; a G transmission; an Iv inverter;

s1, a motor shaft; s2, a transmission shaft;

a Hm motor housing; a Hg transmission case portion; a Hc motor end cover;

c, a cooling liquid flow passage; a C01 inlet; a C02 outlet;

cm motor part flow channel; cc cap section flow channel; cg1 variator portion first flow path; cg2 variator part second flow path; a Cg3 sink chamber; a Cs1 motor shaft flow channel; a Cs2 transmission shaft flow channel; and Ci inverter flow channel.

Detailed Description

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the detailed description is intended only to teach one skilled in the art how to practice the invention, and is not intended to be exhaustive or to limit the scope of the invention.

Referring to fig. 1, a indicates an axial direction of the bridge drive system, which axis direction a coincides with an axial direction of the motor in the bridge drive system, unless otherwise specified; r denotes the radial direction of the bridge drive system, which corresponds to the radial direction of the motor in the bridge drive system.

The bridge drive system according to the present invention includes a motor M, a transmission G, and an inverter Iv.

Preferably, the motor M is arranged coaxially (including coincident and parallel) with the variator G. As shown in fig. 1, a motor shaft S1 provided at the middle of the motor M is coaxially disposed with a transmission shaft S2 provided at the middle of the transmission G. The motor shaft S1 is connected to the rotor Mr of the motor so as not to rotate relative thereto. The motor shaft S1 is also non-rotatably connected to a transmission shaft S2 to transmit power between the motor M and the transmission G.

The present invention is not limited to a specific form of the inverter Iv, and may be integrated with the motor M or provided separately from the motor M, for example.

The housing of the motor M and the housing of the transmission G may be separately manufactured and assembled together, or may be integrally formed. A housing portion corresponding to a region where the motor M is located is referred to as a motor case Hm, and a housing portion corresponding to a region where the transmission G is located is referred to as a transmission case Hg. And a motor end cover Hc is arranged at the end part of the motor shell Hm far away from the transmission G in the axial direction A.

The stator Ms of the motor M is located at the outer periphery of the rotor Mr, and the stator Ms is fixed to the motor casing Hm.

The bridge drive system has a coolant flow passage C for flowing a coolant.

An inlet C01 of the coolant flow passage C is located at the inverter Iv, and is close to the motor end cover Hc in the axial direction a. The outlet C02 of the coolant flow channel C is located at the transmission housing Hg. The coolant can flow into the coolant flow channel C from the inlet C01 and flow out of the coolant flow channel C from the outlet C02. For example, a pump for pumping the cooling liquid may be provided between the inlet C01 and the outlet C02 to promote the flow of the cooling liquid, or a pump may be provided upstream of the inlet C01 or downstream of the outlet C02.

The coolant flow channel C includes two main paths, hereinafter referred to as a first path and a second path. The coolant flowing through the first path is mainly used for cooling the motor shaft S1 and the transmission shaft S2, and the coolant flowing through the second path is mainly used for cooling the motor casing Hm, the transmission casing Hg and the stator Ms.

The first path and the second path are connected in parallel. The coolant flow passage C further includes a path located at the inverter Iv upstream of the first path and the second path and downstream of the inlet C01 to cool down the inverter Iv.

The general course of the first path is shown in fig. 1 by a dot-dash arrow, and the general course of the second path is shown by a dashed arrow.

Referring to fig. 1, a portion of the coolant flow passage C located in the inverter Iv is an inverter flow passage Ci, which is formed, for example, in a housing of the inverter Iv or is formed as a separate pipe from the housing of the inverter Iv, and the inverter flow passage Ci is close to a power component in the inverter Iv, thereby providing efficient cooling for the inverter Iv.

The outlet of the inverter flow passage Ci is connected to the inlet of the coolant flow passage C on the motor casing Hm, thereby delivering the coolant to the first path and the second path.

First, a section of the coolant flow passage C in the first path is described, which includes the cover portion flow passage Cc, the motor shaft flow passage Cs1, the transmission shaft flow passage Cs2, and the transmission portion first flow passage Cg1.

The cover flow passage Cc is formed inside the motor head cover Hc for further conveying the coolant flowing into the system to the motor shaft flow passage Cs1.

The motor shaft flow passage Cs1 and the transmission shaft flow passage Cs2 are respectively formed as passages that penetrate the motor shaft S1 and the transmission shaft S2 in the axial direction a. The motor shaft flow passage Cs1 is communicated with the transmission shaft flow passage Cs2, so that the cooling liquid can flow through the motor shaft S1 and the transmission shaft S2 in sequence, and the cooling of the motor shaft S1 and the transmission shaft S2 is sufficiently realized.

Preferably, a seal ring is provided on the outer periphery of the motor shaft flow passage Cs1 and/or the transmission shaft flow passage Cs2 at the boundary position between the motor shaft S1 and the transmission shaft S2.

Preferably, a seal ring is provided between the motor cover Hc and the motor shaft S1 at the outer periphery of the motor shaft flow passage Cs1.

The coolant flowing through the transmission shaft S2 flows out from the end of the transmission shaft S2 that is away from the motor shaft S1 in the axial direction a, and further flows to the transmission portion first flow passage Cg1.

The transmission section first flow passage Cg1 is formed in the transmission case portion Hg, specifically, inside an end wall of the transmission case portion Hg that is distant from the motor M in the axial direction a.

A sealing ring is preferably arranged on the outer circumference of the transmission shaft flow channel Cs2 between the transmission shaft S2 and an end wall of the transmission housing Hg remote from the electric machine M.

The lower portion of the transmission housing Hg is further formed with a collecting chamber Cg3, and the collecting chamber Cg3 is located below an inner cavity of the transmission housing Hg for accommodating components such as a transmission shaft S2 and gears, so as to facilitate cooling of the inner cavity of the transmission housing Hg, particularly the oil in the inner cavity. The downstream end of the transmission-portion first flow passage Cg1 is connected to the manifold chamber Cg3, so that the coolant flowing through the first path can flow into the manifold chamber Cg3. The coolant in the manifold Cg3 dynamically accumulates a certain volume of coolant, and "dynamic" herein means that the coolant continuously flows into and out of the manifold Cg3, and the coolant in the manifold Cg3 in stages has a good cooling effect on the engine oil in the transmission G.

Preferably, the confluence chamber Cg3 is further formed as the lowest region of the coolant flow channel C to facilitate the confluence of the coolant to the confluence chamber Cg3 by gravity.

Next, a section of the coolant flow passage C in the second path, which includes the motor portion flow passage Cm and the transmission portion second flow passage Cg2, will be described.

The motor section flow channel Cm is formed in a wall of the motor housing section Hm and is conducted from one end of the motor housing section Hm close to the motor end cover Hc to one end of the transmission G in the axial direction a. The upstream end of the motor part flow channel Cm is connected to the downstream end of the inverter flow channel Ci, and the downstream end of the motor part flow channel Cm is connected to the upstream end of the transmission part second flow channel Cg2. The downstream end of the transmission-section second flow passage Cg2 is connected to the manifold chamber Cg3, so that the coolant flowing through the second path can also be merged into the manifold chamber Cg3.

It should be understood that the machine portion flow channel Cm may be a channel formed between the cooling jacket and the machine housing that is nested outside the cooling jacket; or may be formed separately in the wall of the cooling jacket, for example by investment casting, or in the wall of the motor casing. In the case where the motor section flow passage Cm is formed in whole or in part in the cooling jacket, the motor section Hm referred to in the present application is considered to include the cooling jacket.

The motor part flow channel Cm is very close to the stator Ms in the radial direction R, so that the cooling liquid flowing through the motor part flow channel Cm can have a good cooling effect on the motor stator Ms. The motor part flow channel Cm extends in the axial direction a and also extends in the circumferential direction of the motor casing part Hm, so that the motor part flow channel Cm has a large surface area and a large volume in the motor casing part Hm, and the cooling effect on the stator Ms is enhanced. For example, the motor part flow channel Cm extends along a spiral line in the motor casing Hm, or extends along a U-shape or a C-shape in a zigzag manner, and the specific shape of the motor part flow channel Cm is not limited by the present invention. It should be understood that the machine section flow channel Cm in fig. 1 is schematic and does not show the specific structure of the flow channel circumferentially surrounding the machine casing Hm.

In the present embodiment, the coolant flowing through the inverter flow channel Ci flows into the motor section flow channel Cm first, and then is divided into two parts, one of which flows along the first path, and the other of which flows into the lid section flow channel Cc and flows along the second path.

Preferably, a sealing ring is provided between the motor cover Hc and the motor case Hm at the inner and outer circumferences of the motor part flow passage Cm.

It should be understood that the present invention is not limited to the specific location of the connection point of the inverter flow passage Ci, the motor portion flow passage Cm and the cover portion flow passage Cc with each other, for example, the downstream end of the inverter flow passage Ci may be directly connected to the upstream end of the cover portion flow passage Cc, and the upstream end of the motor portion flow passage Cm is connected to the middle region of the cover portion flow passage Cc, so that the cooling liquid flowing out of the inverter flow passage Ci flows into the cover portion flow passage Cc first and then into the motor portion flow passage Cm; for another example, the downstream end of the inverter flow channel Ci is connected to the upstream end of the cover flow channel Cc and the upstream end of the motor section flow channel Cm at the same position, so that the coolant flowing out of the inverter flow channel Ci simultaneously flows into the cover flow channel Cc and the motor section flow channel Cm, respectively.

The invention has at least one of the following advantages:

(i) According to the invention, the communicated motor shaft flow passage Cs1 and the transmission shaft flow passage Cs2 can enable cooling liquid to traverse the motor shaft S1 and the transmission shaft S2, so that the motor shaft S1 and the transmission shaft S2 are well cooled, and a bearing and a sealing ring sleeved outside the shaft cannot be rapidly aged or even fail due to overhigh temperature.

(ii) According to the bridge driving system, the cooling liquid flow channel in the shell can cool the shell and the stator of the motor, so that the power density and the torque density of the motor can be improved, and the service life of an insulating part can be prolonged.

(iii) The manifold Cg3 formed in the lower portion of the transmission case Hg effectively cools the engine oil in the inner cavity of the transmission G.

Of course, the present invention is not limited to the above-described embodiments, and those skilled in the art can make various modifications to the above-described embodiments of the present invention without departing from the scope of the present invention under the teaching of the present invention. For example:

(i) Although in the above embodiment, the regions of the coolant flow passage C other than the motor shaft flow passage Cs1 and the transmission shaft flow passage Cs2 are substantially integrated in the wall of the housing of the system, so that the sealing between the sections of the coolant flow passage C is good and the components of the system are compact. However, in other possible embodiments, a partial section of the coolant flow duct C (in addition to the motor shaft flow duct Cs1 and the transmission shaft flow duct Cs 2) can also be provided separately from the housing of the system (including the motor housing Hm, the transmission housing Hg and the motor cover Hc), for example as a duct separate from the housing.

(ii) The parallel first path and the parallel second path in the above embodiments may also form other connection manners, for example, the first path and the second path may be parallel but not connected to each other, that is, they have respective inlets and outlets; alternatively, the first path and the second path may be connected in series, for example, the downstream end of the inverter flow passage Ci is connected only to the first path, and the downstream of the first path is connected to the second path, in such a scheme that the flow direction of the coolant in the motor portion flow passage Cm is opposite to the flow direction of the coolant in the motor portion flow passage Cm shown in fig. 1, and the outlet C02 is located at the same end of the motor M as the inlet C01 in the axial direction a, which requires a pump for pumping the coolant to have a greater pumping capacity.

(iii) Although the outlet C02 is provided on the side of the transmission G closer to the motor M in the axial direction a in the embodiment shown in fig. 1, this is not essential, and for example, the outlet C02 may be provided on the side of the transmission G farther from the motor M in the axial direction a, or the outlet C02 may be provided at the lower portion of the confluence chamber Cg3.

Claims

1. Bridge drive system with cooling structure, comprising an electric motor (M) and a transmission (G) connected in an axial direction (A), a motor shaft (S1) of the electric motor (M) and a transmission shaft (S2) of the transmission (G) being in power connection with each other,

the bridge drive system has a coolant flow channel (C) for flowing a coolant, the coolant flow channel (C) including a motor shaft flow channel (Cs 1) and a transmission shaft flow channel (Cs 2),

the motor shaft flow channel (Cs 1) penetrates through the motor shaft (S1) in the axial direction (A), the transmission shaft flow channel (Cs 2) penetrates through the transmission shaft (S2) in the axial direction (A), and the motor shaft flow channel (Cs 1) is communicated with the transmission shaft flow channel (Cs 2).

2. The bridge drive system with cooling structure according to claim 1, wherein the electric machine (M) includes an electric machine case portion (Hm), the transmission (G) includes a transmission case portion (Hg),

the coolant flow channel (C) further includes a motor part flow channel (Cm) formed at a wall of the motor casing part (Hm) and a transmission part flow channel (Cm) formed at a wall of the transmission casing part (Hg), the motor part flow channel (Cm) being communicated with the transmission part flow channel.

3. Bridge drive system with cooling structure according to claim 2, characterized in that the motor section flow channel (Cm) extends in the circumferential direction of the motor (M) while extending in the axial direction (a).

4. Bridge drive system with cooling structure according to claim 2, further comprising a motor end cap (Hc) disposed at an end of the motor housing part (Hm) remote from the transmission housing part (Hg) in the axial direction (A),

a cover part flow channel (Cc) is formed in the motor end cover (Hc), and two ends of the cover part flow channel (Cc) are respectively communicated with the motor part flow channel (Cm) and the motor shaft flow channel (Cs 1).

5. The bridge drive system with a cooling structure according to claim 2, wherein the transmission shaft flow passage (Cs 2) communicates with the transmission section flow passage.

6. The bridge drive system with a cooling structure according to claim 5, wherein the transmission portion flow passage includes a transmission portion first flow passage (Cg 1) and a transmission portion second flow passage (Cg 2) respectively located at both ends of the transmission case portion (Hg) in the axial direction (A),

the transmission portion first flow passage (Cg 1) communicates with the transmission shaft flow passage (Cs 2), and the transmission portion second flow passage (Cg 2) communicates with the motor portion flow passage (Cm).

7. The bridge drive system with a cooling structure according to claim 2, wherein the coolant flow passage (C) further includes a manifold chamber (Cg 3) formed in the transmission case portion (Hg), the manifold chamber (Cg 3) being located below an inner cavity of the transmission case portion (Hg).

8. Bridge drive system with cooling arrangement according to claim 7, characterized in that the junction chamber (Cg 3) is located at the lowest of the cooling liquid channels (C).

9. Bridge drive system with cooling arrangement according to claim 7, characterized in that the outlet (C02) of the cooling liquid channel (C) communicates with the manifold chamber (Cg 3).

10. The bridge driving system with the cooling structure according to any one of claims 1 to 9, wherein the cooling liquid flow passage (C) further includes an inverter flow passage (Ci) through which an inverter (Iv) flows, the inverter flow passage (Ci) being located upstream of the motor shaft flow passage (Cs 1) and communicating with an inlet (C01) of the cooling liquid flow passage (C).