KR102566306B1 - Motor cooling structure with selectively opening and closing cooling channels - Google Patents

Abstract

A motor cooling structure having a cooling passage that is selectively opened and closed according to an embodiment of the present invention includes a diffuser for diffusing compressed air passing through an impeller, and a bearing housing disposed on a lower surface of the diffuser and accommodating a bearing therein. wherein, in the diffuser, at least one first through hole is formed along a circumferential direction to pass through the diffuser, and in the bearing housing, at least one second through hole along a circumferential direction corresponds to the first through hole. It is formed to penetrate the bearing housing at a position, and the space above the diffuser is configured to communicate with the motor disposed at the rear of the bearing housing through the first through hole and the second through hole, and the lower surface of the diffuser or the second through hole. A band-shaped space is formed along the circumferential direction on the upper surface of the bearing housing so that both the first through hole and the second through hole communicate with each other, and a diffuser ring including a ring member and an opening/closing protrusion is disposed in the space. The protrusion is made of a bimetal and is configured to closely close the first through hole or the second through hole in a low temperature environment and to open the first through hole or the second through hole in a high temperature environment.

Description

Motor cooling structure with selectively opened and closed cooling channels {MOTOR COOLING STRUCTURE WITH SELECTIVELY OPENING AND CLOSING COOLING CHANNELS}

The present invention relates to a motor cooling structure having a cooling passage that is selectively opened and closed. In particular, a cooling passage is formed in a diffuser and a bearing housing to directly supply compressed air from a compressor wheel to a motor housing through the cooling passage. is a motor cooling structure in which a cooling passage is formed which can be selectively opened and closed according to the temperature of the motor by a diffuser ring having a bimetal structure.

To cool the motor of the air compressor, a water cooling method by circulation of cooling water and an air cooling method using circulation of cooling air are adopted. In the water cooling method, a cooling water jacket is provided inside the housing to be adjacent to the motor to cool heat generated during operation of the motor. The coolant flowing through the coolant jacket cools the motor by exchanging heat with the motor. On the other hand, the air cooling method uses compressed air that has passed through the rear surface of the compressor wheel of the impeller to cool it. Float bearings and journal bearings. And, some of the compressed air flows directly into the motor housing through the diffuser hole to cool the motor. A flow path of compressed air through the diffuser hole is referred to as a secondary flow path for convenience. Here, there is an advantage of high motor cooling efficiency as a part of the air that has passed through the diffuser hole is used for direct cooling of the motor, but pressure leakage occurs as a part of the compressed air is directly used for motor cooling through the secondary passage. , there is a problem that the efficiency of the compressor is lowered.

Accordingly, there is a need for an optimized cooling structure capable of satisfying both motor cooling and compressor efficiency.

The present invention was created to solve the above-mentioned problems, and an object of the present invention is to close the cooling passage in the low temperature region using a bimetal, and to open the cooling passage only at the maximum output at which the heat generation of the motor increases, thereby reducing unnecessary performance and provide a cooling structure capable of additionally cooling the motor only when necessary.

A motor cooling structure having a cooling passage that is selectively opened and closed according to an embodiment of the present invention for achieving the above object is a diffuser for diffusing compressed air passing through an impeller, and disposed on the lower surface of the diffuser to A bearing housing accommodating a bearing, wherein at least one through hole is formed in the diffuser and the bearing housing along a circumferential direction to pass through the diffuser and the bearing housing, and on the lower surface of the diffuser or the upper surface of the bearing housing A band-shaped space is formed along the circumferential direction so that the through-holes communicate with each other, and a diffuser ring is disposed in the space, and the diffuser ring is made of bimetal to closely close the through-hole in a low-temperature environment and to It is configured to open a through hole.

In addition, the through hole is composed of a first through hole formed in the diffuser and a second through hole formed in the bearing housing at a position corresponding to the first through hole, and the space above the diffuser is formed between the first through hole and the through hole. It may be configured to communicate with a motor disposed behind the bearing housing through the second through hole.

In addition, the diffuser ring includes a circular ring member and a plurality of opening and closing protrusions, each opening and closing protrusion protrudes to the inside of the ring member, and the opening and closing protrusion is made of a bimetal, and in a low-temperature environment, the first through-hole or It may be configured to closely close the second through-hole and open the first through-hole or the second through-hole in a high-temperature environment.

In addition, the space is composed of a seating space recessed in the upper surface of the bearing housing and accommodating the diffuser ring, and an entry allowing space recessed in the lower surface of the diffuser to allow entry of the opening and closing protrusion, and the ring member A position is fixed between the diffuser and the bearing housing, the opening/closing protrusion is positioned to cover the second through hole, and the opening/closing protrusion may be configured to open the second through hole by bending toward the entry allowance space in a high temperature environment. .

In addition, the diffuser ring is made of a combination of two metal plates having different thermal expansion coefficients, and the thermal expansion coefficient of the second member on the bearing housing side is greater than that of the first member on the diffuser side.

On the other hand, a motor cooling structure having a cooling passage that is selectively opened and closed according to another embodiment of the present invention includes a diffuser for diffusing compressed air passing through an impeller, and a diffuser disposed on a lower surface of the diffuser to accommodate a bearing therein. It includes a bearing housing, the diffuser has at least one first through hole formed along a circumferential direction to pass through the diffuser, and the bearing housing has at least one second through hole formed along a circumferential direction along the first through hole. It is formed to penetrate the bearing housing at a position corresponding to, and the space above the diffuser is configured to communicate with a motor disposed at the rear of the bearing housing through the first through hole and the second through hole, and the bearing housing An opening and closing member for individually opening and closing each of the second through holes is installed on the upper surface of, and the opening and closing member has one end coupled to the upper surface of the bearing housing as a fixed end and the other end covering the second through hole as a free end, , The opening and closing member is made of a bimetal so as to closely close the second through-hole in a low-temperature environment and open the second through-hole in a high-temperature environment.

According to an embodiment of the present invention, when the motor operates at low power, the cooling passage is blocked to optimize aerodynamic performance, thereby reducing power consumption of the motor.

In addition, when the air temperature rises when the motor operates at high power output, the diffuser ring is automatically deformed to open the cooling passage and additionally supply cooling air for cooling the motor.

1 is a conceptual diagram for explaining the overall structure of an air compressor.
2 is a conceptual diagram illustrating a motor cooling structure having a cooling passage that is selectively opened and closed according to an embodiment of the present invention.
Figure 3 is a cross-sectional view of Figure 2;
4A and 4B are enlarged cross-sectional perspective views of the motor cooling structure in FIG. 2 .
5 is a perspective view of a motor cooling structure according to still another embodiment of the present invention.
6 is a perspective view of a diffuser ring used in the cooling structure of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in many different forms, and the scope of the present invention is as follows It is not limited to the examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the invention to those skilled in the art.

In addition, in the following drawings, the thickness or size of each layer is exaggerated for convenience and clarity of explanation, and the same reference numerals refer to the same elements in the drawings. As used herein, the term "and/or" includes any one and all combinations of one or more of the listed items. In addition, the meaning of "connected" in the present specification means not only when member A and member B are directly connected, but also when member A and member B are indirectly connected by interposing member C between member A and member B. do. Terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Also, when used herein, “comprise, include” and/or “comprising, including” refers to a referenced form, number, step, operation, member, element, and/or group thereof. presence, but does not preclude the presence or addition of one or more other shapes, numbers, operations, elements, elements and/or groups.

In this specification, terms such as first and second are used to describe various members, components, regions, layers and/or portions, but these members, components, regions, layers and/or portions are limited by these terms. It is self-evident that These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described in detail below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

Space-related terms such as “beneath,” “below,” “lower,” “above,” and “upper” are associated with an element or feature shown in a drawing. It can be used for easy understanding of other elements or features. Terminology related to this space is for easy understanding of the present invention according to various process conditions or use conditions of the present invention, and is not intended to limit the present invention. For example, if an element or feature in a figure is turned over, an element or feature described as "lower" or "below" becomes "above" or "above." Accordingly, "below" is a concept encompassing "upper" or "below".

1 is a conceptual diagram for explaining the overall structure of an air compressor, FIG. 2 is a conceptual diagram showing a motor cooling structure having a cooling passage that is selectively opened and closed according to an embodiment of the present invention, FIG. 3 is a cross-sectional view of FIG. 4a and 4b are enlarged sectional perspective views of the motor cooling structure in FIG. 2, and FIG. 6 is a perspective view of a diffuser ring used in the cooling structure of the present invention. Hereinafter, a motor cooling structure having a cooling passage that is selectively opened and closed according to an embodiment of the present invention will be described.

Referring to FIG. 1 , the air compressor compresses air sucked in from the outside using an impeller (see FIG. 2 ) and then discharges the compressed air through an exhaust port. In the case of hydrogen cell vehicles, compressed air is sent to the fuel cell stack. At this time, the air-cooling method uses air that has passed through the rear surface of the compressor wheel of the impeller to cool the heating part. The air that has passed through the rear surface of the compressor wheel passes through the diffuser and thrust bearing, then through the front journal bearing to the rear of the shaft. It moves and passes through the rear journal bearing and flows to the rear of the housing.

Motor cooling structure 100 according to an embodiment of the present invention is a combination of a diffuser 110 and a bearing housing 130, the diffuser 110 for diffusing compressed air passing through the impeller, and the lower surface of the diffuser 110 It is arranged to include a bearing housing 130 for accommodating the bearing therein. At least one through hole is formed in the diffuser 110 and the bearing housing 130 in a circumferential direction to penetrate the diffuser 110 and the bearing housing 130 . These through holes are composed of a first through hole 111 formed in the diffuser and a second through hole 131 formed in the bearing housing at a position corresponding to the first through hole 111 .

The space above the diffuser is configured to communicate with a motor disposed behind the bearing housing through the first through hole and the second through hole,

Specifically, the diffuser 110 is a circular plate-shaped member, and at least one first through hole 111 is formed along the circumferential direction of the diffuser 110 to penetrate the diffuser 110 in an axial direction. In addition, a front bearing housing 130 accommodating and supporting a thrust bearing and a journal bearing installed in front of the shaft is coupled to the rear of the diffuser 110, and the bearing housing 130 includes at least one second bearing along its circumferential direction. The through hole 131 is formed to penetrate the bearing housing 130 in the axial direction. At this time, the second through hole 131 is formed at a position corresponding to the first through hole 111 . As shown, the bearing housing 130 has a flat cylindrical space for accommodating a bearing therein, and the second through hole 131 is formed along the outer circumference of the cylindrical space. Thus, the compressed air passing through the second through hole 131 exists independently of the receiving space of the thrust bearing or journal bearing.

In this way, by processing the first through hole 111 and the second through hole 131 at corresponding positions and combining the diffuser 110 and the bearing housing 130, the first and second through holes 131 are mutually connected. As a result, some of the compressed air passing through the compressor wheel and entering the diffuser 110 passes through the first through hole 111 of the diffuser 110 and the second through hole 131 of the bearing housing 130. It is introduced to the rear through and enters the inside of the motor housing located at the rear of the bearing housing 130. A flow path of compressed air through the first and second through holes is referred to as an auxiliary cooling passage (secondary passage) for convenience.

Meanwhile, according to the present invention, the auxiliary cooling passage has a structure that is selectively opened and closed by the diffuser ring 170 .

First, as shown in FIG. 6 , the diffuser ring 170 may adopt a circular frame shape having a thin overall thickness. The diffuser ring 170 includes a circular ring member 173 and a plurality of opening/closing protrusions 174, which may be integrally formed of the same material. As shown in FIG. 3, the circular ring member 173 is sandwiched between the diffuser 110 and the bearing housing 130, and its position is fixed due to the fastening between the diffuser 110 and the bearing housing 130. A plurality of opening and closing protrusions 174 may be provided, and the plurality of opening and closing protrusions 174 protrude into the circular ring member 173 . One end of the opening/closing protrusion 174 is coupled integrally with the ring member 173 as a fixed end, but the other end is a free end and can be bent in one direction up and down.

At this time, the diffuser ring 170 according to the present invention is composed of a combination of two metal plates having different coefficients of thermal expansion, that is, a bimetal. Bimetal refers to a material made by attaching two metals having different properties. In the present invention, the diffuser ring 170 is formed by attaching two different metal plates having different coefficients of thermal expansion by welding. A metal with a high coefficient of thermal expansion expands more than the other metal, causing warping toward the metal with a lower coefficient of thermal expansion. In the present invention, since one side of the opening and closing protrusion 174 is a free end, bending occurs in only one direction depending on the surrounding temperature environment due to the difference in thermal expansion coefficient described above.

Next, a space formed between the diffuser 110 and the bearing housing 130 in relation to the arrangement of the diffuser ring 170 will be described. On the lower surface of the diffuser 110 or the upper surface of the bearing housing 130, a strip-shaped space is formed along the circumferential direction so that both the first through hole 111 and the second through hole 131 communicate with each other. For example, referring to FIGS. 4A and 4B , a seating space having a circular track shape is formed on the upper surface of the bearing housing 130 . The seating space extends from the upper surface of the bearing housing 130 in the circumferential direction and has a shape that is recessed inward by recess processing, and the diffuser ring 170 includes a ring member 173 and an opening/closing protrusion 174 in the corresponding space. this is accepted The recessed depth is preferably corresponding to the height of the diffuser ring 170, specifically, the ring member 173 of the diffuser ring 170 in terms of fixing the diffuser ring 170. Meanwhile, on the lower surface of the diffuser 110, an entry allowance space 113 is formed in an area corresponding to the opening/closing protrusion 174. That is, when the diffuser ring 170 is disposed in a space composed of the seating space of the bearing housing 130 and the entry allowance space 113 of the diffuser 110, the entry allowance space 113 opens and closes the diffuser ring 170. It exists above the protrusion 174. As described above, the diffuser ring 170 is made of bimetal, and the thermal expansion coefficient of the second member 172 on the side of the bearing housing 130 is greater than that of the first member 171 on the side of the diffuser 110. big. Accordingly, in a high temperature environment, the opening and closing protrusion 174 is bent toward the diffuser 110, and the entry allowance space 113 exists above the opening and closing protrusion 174, so that the opening and closing protrusion 174 of the diffuser ring 170 Unaffected by bending

According to the structure described above, the position of the ring member 173 of the diffuser ring 170 is fixed between the diffuser 110 and the bearing housing 130, and the opening/closing protrusion 174 is second through the bearing housing 130. Cover the hole 131. At this time, when the environment around the opening and closing protrusion 174 becomes a high temperature environment, the opening and closing protrusion 174 is bent upward toward the entry allowance space 113, and accordingly, the second through hole 131 covered by the opening and closing protrusion 174 ) is opened. Conversely, when the environment around the opening/closing protrusion 174 becomes a low-temperature environment, the opening/closing protrusion 174 closely closes the second through hole 131 .

In the above, a seating space is formed on the upper surface of the bearing housing 130 to accommodate the diffuser ring 170, and the opening/closing protrusion 174 of the diffuser ring 170 passes through the second through hole 131 of the bearing housing 130. The second member 172 on the side of the bearing housing 130 is closed, and the opening and closing protrusion 174 is made of a metal having a higher thermal expansion coefficient than the first member 171 on the side of the diffuser 110, so that the second penetrating at high temperature. The structure of opening the hole 131 has been described.

A mechanism for selectively opening and closing the cooling passage in this structure will be described. The impeller and the diffuser 110 rotate together with the shaft, and the shaft rotates by driving the motor 150. When the motor 150 operates at a low speed, the power consumption is small and the temperature of the motor 150 is low, so that the motor ( 150) does not require cooling air for cooling. Conversely, when the motor 150 rotates at a high speed, a lot of power is consumed, and thus the temperature of the motor 150 rises. Accordingly, additional cooling air for cooling the motor is required.

When the motor 150 operates at a low speed, the temperature of the motor 150 is low and the opening/closing protrusion 174 of the diffuser ring 170 does not cause thermal deformation. Accordingly, the second through hole 131 is closed as it is. When the second through hole 131 is blocked, the pressure loss of the compressor decreases and the efficiency of the entire system increases, so unnecessary power consumption can be suppressed. Meanwhile, when the motor 150 operates at a high speed, the motor 150 is in a high-temperature state, so the surrounding environment of the opening/closing protrusion 174 of the diffuser ring 170 is in a high-temperature state. Then, the opening/closing protrusion 174 made of bimetal opens the second through hole 131 covered while bending upward. Thereafter, the first through hole 111 and the second through hole 131 communicate with each other so that air for cooling the motor 150 flows through the first through hole 111 and the second through hole 131 from above the diffuser 110. ) to enter the motor housing.

Accordingly, depending on the output value of the motor 150, the opening/closing state of the cooling passage is automatically set, so that cooling air can be selectively introduced into the motor side only when cooling the motor is necessary. Accordingly, there is an advantage in that it is possible to automatically control whether cooling air is introduced or not, and unnecessary performance degradation (power consumption) can be prevented.

Meanwhile, as another embodiment, a seating space is formed on the lower surface of the diffuser 110 to accommodate the diffuser ring 170, and the opening/closing protrusion 174 of the diffuser ring 170 forms a first through hole of the diffuser 110 ( 111), and the opening and closing protrusion 174 is made of a metal having a higher coefficient of thermal expansion than the second member 172 on the side of the bearing housing 130 so that the first member 171 on the side of the diffuser 110 is used in a high-temperature environment. It is also possible to transform the structure into a structure in which the opening and closing protrusion 174 is bent downward to selectively open the first through hole 111 .

Second embodiment

5 is a perspective view of a motor cooling structure according to still another embodiment of the present invention. The motor cooling structure 100 according to the second embodiment includes a diffuser 110 for diffusing compressed air passing through an impeller, and a bearing housing 130 disposed on a lower surface of the diffuser 110 and accommodating a bearing therein. In the diffuser 110, at least one first through hole 111 is formed to pass through the diffuser 110 along the circumferential direction, and the bearing housing 130 has at least one second through hole along the circumferential direction. A hole 131 is formed to pass through the bearing housing 130 at a position corresponding to the first through hole 111 . Accordingly, the space on the diffuser 110 is configured to communicate with the motor 150 disposed behind the bearing housing 130 through the first through hole 111 and the second through hole 131 . The configuration above is the same as that of the first embodiment.

However, according to the second embodiment, an opening and closing member 180 that individually opens and closes each of the second through holes 131 is installed on the upper surface of the bearing housing 130 . That is, one end of the opening/closing member 180 is coupled to the upper surface of the bearing housing 130 as a fixed end and the other end covers the second through hole 131 as a free end. The fixed end may be coupled to the bearing housing 130 using a method such as bolt fastening.

Meanwhile, similar to the first embodiment, the opening/closing member 180 is made of bimetal, so that the second through hole 131 is tightly closed in a low temperature environment and the second through hole 131 is opened in a high temperature environment.

In the first embodiment, one seating space for accommodating the diffuser ring 170 was formed on the upper surface of the bearing housing 130 along the circumferential direction on the upper surface of the bearing housing 130, but in the structure of the second embodiment, the diffuser The ring 170 is not employed, and instead, individual opening and closing members 180 are configured to individually open and close the corresponding second through holes 131 . Accordingly, individual seating spaces accommodating the opening/closing member 180 are required, and one seating space extending in the circumferential direction is not employed.

What has been described above is only one embodiment for implementing a diffuser having a cooling passage that is selectively opened and closed according to the present invention, and the present invention is not limited to the above-described embodiment, and claims in the following claims As such, anyone skilled in the art in the field to which the present invention pertains without departing from the gist of the present invention will say that the technical spirit of the present invention exists to the extent that various changes can be made.

100: motor cooling structure 110: diffuser
111: first through hole 130: bearing housing
131: second through hole 150: motor
170: diffuser ring 173: ring member
174: opening and closing protrusion 180: opening and closing member

Claims (6)

A diffuser for diffusing compressed air passing through the impeller, and a bearing housing disposed on a lower surface of the diffuser to accommodate bearings therein,
At least one through hole is formed in the diffuser and the bearing housing along a circumferential direction to pass through the diffuser and the bearing housing,
A strip-shaped space is formed along the circumferential direction so that the through holes communicate with each other on the lower surface of the diffuser or the upper surface of the bearing housing,
Characterized in that a diffuser ring is disposed in the space, and the diffuser ring is made of bimetal to tightly close the through-hole in a low-temperature environment and to open the through-hole in a high-temperature environment.
A motor cooling structure having a cooling passage that is selectively opened and closed. According to claim 1,
The through hole is composed of a first through hole formed in the diffuser and a second through hole formed in the bearing housing at a position corresponding to the first through hole,
The space above the diffuser is configured to communicate with a motor disposed behind the bearing housing through the first through hole and the second through hole,
A motor cooling structure having a cooling passage that is selectively opened and closed. According to claim 2,
The diffuser ring includes a circular ring member and a plurality of opening and closing protrusions, and each opening and closing protrusion protrudes to the inside of the ring member,
Characterized in that the opening and closing protrusion is composed of a bimetal, configured to closely close the first through hole or the second through hole in a low temperature environment and open the first through hole or the second through hole in a high temperature environment.
A motor cooling structure having a cooling passage that is selectively opened and closed. According to claim 3,
The space is composed of a seating space recessed in the upper surface of the bearing housing and accommodating the diffuser ring, and an entry allowing space recessed in the lower surface of the diffuser to allow entry of the opening and closing protrusion,
The position of the ring member is fixed between the diffuser and the bearing housing, the opening/closing protrusion is positioned to cover the second through hole, and the opening/closing protrusion is bent toward the entry allowance space in a high-temperature environment to open the second through hole. which is composed of,
A motor cooling structure having a cooling passage that is selectively opened and closed. According to claim 4,
The diffuser ring is made of a combination of two metal plates having different thermal expansion coefficients, and the thermal expansion coefficient of the second member on the bearing housing side is greater than the thermal expansion coefficient of the first member on the diffuser side.
A motor cooling structure having a cooling passage that is selectively opened and closed. A diffuser for diffusing compressed air passing through the impeller, and a bearing housing disposed on a lower surface of the diffuser to accommodate bearings therein,
At least one first through hole is formed along a circumferential direction of the diffuser to pass through the diffuser, and at least one second through hole is formed in the bearing housing along a circumferential direction at a position corresponding to the first through hole. It is formed to penetrate the bearing housing,
The space above the diffuser is configured to communicate with the motor disposed at the rear of the bearing housing through the first through hole and the second through hole, and individually open and close each of the second through holes on the upper surface of the bearing housing. An opening and closing member is installed,
The opening and closing member has one end coupled to the upper surface of the bearing housing as a fixed end and the other end as a free end to cover the second through hole,
Characterized in that the opening and closing member is composed of a bimetal and configured to closely close the second through-hole in a low-temperature environment and open the second through-hole in a high-temperature environment.
A motor cooling structure having a cooling passage that is selectively opened and closed.