TWI513151B - Motor with air cleaning apparatus - Google Patents

Description

Motor with air purifying device

The present invention relates to a motor having an air purifying device, and more particularly to a motor having an air purifying device capable of diffusing air purifying particles generated by the air purifying device into a surrounding air via an air flow passage.

Referring to FIG. 1 , a fan 9 having an air purifying device includes a fan body 91 and an negative ion device 92. The fan body 91 is provided with a chamber 911 for the negative ion device 92. The fan body 91 is provided with an air outlet 912 that communicates with the chamber 911. The air outlet 91 is formed in the same direction as the airflow blown by the fan body 91. Thereby, the negative ions generated by the negative ion device 92 can be sent out by the air outlet 912, and the air outlet 912 is formed in the same direction as the airflow blown by the fan body 91, so that the negative ions generated by the negative ion device 92 can be affected. The airflow blown by the fan body 91 is driven to spread and spread to achieve the effect of purifying the air. An embodiment of the fan 9 having an air purifying device has been disclosed in the Patent Case No. M242591 of the Republic of China, "Electric Fan with Negative Ion Device".

The negative ions generated by the negative ion device 92 of the fan 9 having the air purifying device must be driven by the airflow blown by the fan body 91 to be effectively diffused and propagated into the air. In other words, the negative ion device 92 must be matched with the fan body 91. Can work. The fan body 91 includes a conventional motor for driving a fan wheel to rotate to generate airflow and blow through an air outlet. However, the application of the conventional motor is extensive, and the conventional motor is not connected to the fan wheel in many applications, for example, in an elevator, an electric car, an iron door or an optical disk drive. The motor in the motor does not need to be connected to the fan wheel, so that the negative ion device 92 cannot be used with the motor in the above various situations, so that the application range of the negative ion device 92 is narrow.

Furthermore, in order for the negative ions generated by the negative ion device 92 to be sent out from the air outlet 912 of the fan body 91, the negative ion device 92 must be disposed adjacent to the air outlet 912 of the fan body 91, thereby causing the negative ion device 92. The setting location is limited. In fact, a commercially available fan having a negative ion generating function must be disposed at a position adjacent to the fan wheel of the fan to ensure that the negative ions generated by the negative ion device 92 can be propagated through the airflow driven by the fan wheel. . However, since the air flowing near the position of the fan wheel is relatively fast, the negative ion device 92 can ionize the nearby airflow to form a negative ion. Therefore, the efficiency of generating a negative ion by a fan having a negative ion generating function is not satisfactory.

In summary, the negative ion device 92 of the fan 9 having the air purifying device must be operated in conjunction with the motor connected to the fan wheel, and the negative ion device 92 must be disposed adjacent to the fan wheel, resulting in the negative ion device 92 being generated. The efficiency of negative ions is low, and the effect of purifying air is poor. In view of the above, there is a need to provide a motor having an air purifying device to solve the above problems of "narrow application range" and "poor air purification effect" of the negative ion device 92, by integrating air purification functions such as negative ion generation or ozone generation. Among the motors, the motor can be connected to the fan wheel to achieve the effect of purifying the air, thereby effectively improving the functional diversity and practicability of the motor.

An object of the present invention is to provide a motor having an air purifying device, by using a rotor to provide a guide vane, and providing an air flow passage connecting the inner space and the outer space of the motor, and using the guide vane to the motor The internal space drives the airflow to discharge the negative ions generated by an air purifying device or the ozone molecules to the external space of the motor through the airflow passage, so that the motor has an air purifying function, and has the effect of improving the utility of the motor.

Another object of the present invention is to provide a motor having an air purifying device, by disposing a transmitting end of the air purifying device in an inner space of the motor, which can avoid the air purifying when the motor is connected to a fan wheel The action of the negative ions or ozone molecules generated by the device is affected by the airflow driven by the fan wheel to ensure the efficiency of the negative ion or ozone molecules generated by the air purifying device, and has the effect of improving the effect of purifying the air.

In order to achieve the foregoing object, the technical means used in the present invention include: a motor having an air purifying device, comprising: a certain subgroup, the stator assembly is coupled to a base; and a rotor rotatably coupled to the stator The rotor is provided with a guide vane, and the base and the rotor surround an internal space. The stator assembly is disposed in the internal space. The rotor includes a casing, and the casing is rotatably coupled to the casing. a stator assembly, the housing and the base surround the inner space, the guide vane has a first end edge and a second end edge, the first end edge of the guide vane is coupled to the housing; An air flow passage connecting the inner space of the motor and an outer space; and an air purifying device coupled to the base or the stator group, and the air purifying device is provided with a transmitting end, The transmitting end is disposed in the internal space.

The present invention has a motor for an air purifying device, wherein the air flow passage includes a through hole, the through hole is defined in the base, and the through hole is penetrated through the base to respectively communicate with the inner space and the outer space of the motor.

The present invention has a motor of an air purifying device, wherein an emitting end of the air purifying device is disposed toward the through hole.

The motor of the present invention has an air purifying device, wherein the air flow passage includes a gap formed between the housing of the rotor and the base to respectively communicate the internal space and the external space of the motor.

The present invention has a motor of an air purifying device, wherein an emitting end of the air purifying device is disposed toward the gap.

The motor of the present invention further includes a circuit board, the circuit board is coupled to the base, the air purifying device is electrically connected to the circuit board, and the guide vane is directed from the first end edge The direction of the board extends to the second end edge.

The invention has a motor of an air purifying device, wherein the casing opens a vent opening through the inner space, and the first end edge of the guide vane is connected to the periphery of the vent.

The motor of the present invention further includes a circuit board, the circuit board is coupled to the base, the air cleaning device is electrically connected to the circuit board, and the guide vane is along the first end edge Extending from one of the boards to the second end edge.

The present invention has a motor of an air purifying device, wherein the stator assembly includes an iron core, the iron core is received in a casing of the rotor, and the iron core has a through hole penetrating the iron core so that the inner core Airflow in the space can flow from the guide vanes of the rotor to the airflow passage via the perforations.

The motor of the present invention has an air purifying device, wherein the air flow passage includes a through hole, the through hole is defined in the base, and the through hole is penetrated through the base to respectively communicate with the inner space and the outer space of the motor, A perforation extends through the core such that airflow in the interior space can flow from the guide vanes of the rotor through the perforations to the through hole.

The motor of the present invention further includes a circuit board, the circuit board is coupled to the stator set, the air purifying device is electrically connected to the circuit board, and the emitting end of the air purifying device is oriented toward the guide Flow blade setting.

The motor of the present invention has an air purifying device, wherein the air purifying device is an negative ion generator for generating negative ions at the emitting end, and the guiding vane can be rotated with the rotor to drive in the inner space of the motor. An air flow is generated that will drive the negative ions to exit the outer space of the motor via the air flow passage.

The motor of the present invention has an air purifying device, wherein the air purifying device is an ozone generator for generating ozone molecules at the emitting end, and the guiding vanes can follow the turn The sub-rotation is driven to generate an air flow in the inner space of the motor, and the air flow will drive the ozone molecules to be discharged to the outer space of the motor via the air flow passage.

〔this invention〕

1‧‧‧Base

2‧‧‧stator group

21‧‧‧ iron core

211‧‧‧Perforation

22‧‧‧Exciting coil

3‧‧‧Rotor

31‧‧‧Shell

311‧‧‧ vents

32‧‧‧Permanent magnet set

33‧‧‧Guide vanes

33a‧‧‧First edge

33b‧‧‧second edge

4‧‧‧Air passage

41‧‧‧through hole

42‧‧‧ gap

5‧‧‧Air purification device

51‧‧‧transmitter

6‧‧‧Circuit board

R‧‧‧Internal space

[study]

9‧‧‧Use a fan with an air purifier

91‧‧‧Fan body

911‧‧ ‧ room

912‧‧‧ outlet

92‧‧‧ Negative ion device

Fig. 1 is a cross-sectional view showing the structure of a conventional fan having an air purifying device.

Fig. 2 is a perspective exploded view of the first embodiment of the present invention.

Figure 3 is a cross-sectional view showing the structure of a first embodiment of the present invention.

Figure 4 is a cross-sectional view showing the structure of a second embodiment of the present invention.

Figure 5 is a cross-sectional view showing the structure of a third embodiment of the present invention.

Figure 6 is a cross-sectional view showing the structure of a fourth embodiment of the present invention.

Fig. 7 is a schematic view showing the appearance of an iron core according to a fourth embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt; A motor having an air purifying device according to a first embodiment of the present invention. In the embodiment, the motor having the air purifying device is an outer rotor motor, but the motor having the air purifying device may also be an inner rotor. The motor is not limited by the invention. The motor having the air purifying device of the first embodiment comprises a base 1, a certain subgroup 2, a rotor 3, an air flow passage 4 and an air purifying device 5, and the stator assembly 2 is fixedly coupled to the base 1, the The rotor 3 is rotatably coupled to the stator assembly 2, the air flow passage 4 is connected to an inner space R of the motor and an outer space, and the air cleaning device 5 is coupled to the base 1 or the stator assembly 2. The internal space R of the motor refers to a space formed by the base 1 and the rotor 3, and the stator set 2 is disposed in the internal space R; the external space of the motor generally refers to the internal space of the motor. Space other than R.

The base 1 can be combined by various conventional methods such as locking, splicing, screwing or snapping. The method combines the stator assembly 2 directly or indirectly such that the stator assembly 2 and the base 1 are fixedly coupled to each other.

The stator assembly 2 includes an iron core 21, and an exciting coil 22 can be wound around the outer circumference of the iron core 21. The rotor 3 includes a housing 31 rotatably coupled to the stator assembly 2, and the housing 31 and the base 1 surround the internal space R for receiving a permanent magnet group 32 and The stator set 2. The permanent magnet group 32 is preferably disposed on the inner peripheral wall of the casing 31. The permanent magnet group 32 is disposed toward the iron core 21, and the permanent magnet group 32 and the iron core 21 have an air gap therebetween. Since the stator set 2 and the rotor 3 are well-known technologies that can be easily understood by those skilled in the art, the detailed structure and operation principle are not described herein.

The rotor 3 is provided with a guide vane 33 which can be coupled to the housing 31 and which extends towards the internal space R. Thereby, when the stator group 2 drives the rotor 3 to operate, the rotation of the casing 31 of the rotor 3 will simultaneously drive the guide vane 33 to rotate, and then the guide vane 33 is driven to generate a flow toward the internal space R of the motor. Airflow.

The air flow generated by the rotation of the guide vanes 33 of the rotor 3 can be discharged to the outer space of the motor via the air flow passage 4. In this embodiment, the air flow channel 4 includes a through hole 41. The through hole 41 is defined in the base 1. The through hole 41 extends through the base 1 to respectively communicate with the internal space R and the external space of the motor. .

The air purifying device 5 can be a negative ion generator or an ozone generator electrically connected to a transmitting end 51. The air cleaning device 5 can be coupled to the base 1 or the stator assembly 2, and the transmitting end 51 is disposed in the internal space R of the motor. More specifically, the motor of the first embodiment having the air purifying device may further include a circuit board 6 coupled to the base 1 , and the air purifying device 5 is connected via an electrical connection line (not shown) And the circuit board 6 is electrically connected to the base 1 and the air purifying device 5 can obtain power from the circuit board 6 to control its operation.

Thereby, when the air purifying device 5 is a negative ion generator, the air purifying The device 5 can convert the low voltage into a DC negative high voltage by using a conventional boosting element such as a pulse circuit and an oscillator, and then deliver it to the transmitting end 51 to ionize the nearby airflow to form a negative ion; or, when the air purifying device 5 is ozone generating The air purifying device 5 converts the low voltage into an alternating high voltage through a transformer, so that a high voltage electric field region is formed near the emitting end 51 for ionizing oxygen molecules in the air to form oxygen ions, and the oxygen ions will be Oxygen molecules in the air combine to form ozone molecules.

With the above structure, the emitting end 51 of the air cleaning device 5 can generate negative ions or ozone molecules in the internal space R of the motor, and at the same time, the guiding vane 33 can be in the internal space of the motor as the rotor 3 rotates. The drive in R generates a gas flow that will drive the negative ions or the ozone molecules to exit the outer space of the motor via the gas flow passage 4. In other words, in the present embodiment, the negative ions or the ozone molecules can be driven by the airflow driven by the guide vanes 33 to be discharged to the external space of the motor through the through holes 41 opened in the base 1 to spread and spread. To the surrounding air. Therefore, the negative ions can cause negative charges (electrostatic) in the air such as dust, pollen, smoke, etc., and thus are easily attracted by the ground to precipitate, thereby purifying the air; or the ozone molecules can be in the air. It achieves the effect of purifying air such as sterilization and deodorization.

It should be noted that the guide vane 33 has a first end edge 33a and a second end edge 33b. The first end edge 33a is coupled to the housing 31, and the guide vane 33 is preferably The one end edge 33a extends toward the circuit board 6 to the second end edge 33b. Thereby, the guiding vane 33 can drive the airflow flowing toward the circuit board 6 as the rotor 3 rotates. Since the air purifying device 5 is electrically connected to the circuit board 6, the airflow can effectively drive the airflow. The negative ions or ozone molecules generated by the air purifying device 5 are discharged to the external space of the motor through the air flow path 4, and the air current flowing toward the circuit board 6 can collectively dissipate the circuit board 6.

Furthermore, the emitting end 51 of the air cleaning device 5 preferably faces the air flow passage 4 is arranged such that negative ions or ozone molecules formed in the vicinity of the emitting end 51 are easily discharged to the outer space of the motor via the air flow path 4. In the present embodiment, the air flow channel 4 includes a through hole 41 formed in the base 1 , and thus the transmitting end 51 is preferably disposed toward the through hole 41 .

Further, when the concentration of negative ions or ozone molecules in the vicinity of the emitting end 51 rises, the efficiency of generating negative ions or ozone molecules by the air purifying device 5 is drastically lowered due to a relative decrease in the number of electrically neutral molecules or oxygen molecules. Accordingly, the housing 31 of the rotor 3 can open through a vent 311 of the internal space R. The first end edge 33a of the guide vane 33 is connected to the periphery of the vent 311, so that the guide vane 33 rotates. Air can be introduced into the internal space R from outside the casing 31 via the vent 311, and air introduced from the outside of the casing 31 can effectively supplement the electrically neutral molecules or oxygen molecules in the internal space R of the motor. To ensure that the air purification device 5 continues to generate negative ions or ozone molecules.

Referring to FIG. 4, a motor having an air purifying device according to a second embodiment of the present invention is different from the foregoing first embodiment in that, in the embodiment, the air flow passage 4 includes a gap 42. The gap 42 is formed between the casing 31 of the rotor 3 and the base 1 to communicate with the internal space R of the motor and the external space, respectively. Therefore, the airflow generated by the rotation of the guide vanes 33 of the rotor 3 can drive the negative ions or ozone molecules generated by the air cleaning device 5 to be discharged to the external space of the motor via the gap 42. Therefore, in this embodiment, The transmitting end 51 is preferably disposed toward the gap 42.

On the other hand, the motor of the second embodiment having the air purifying device is an inner rotor motor, and the permanent magnet group 32 of the rotor 3 is rotatably coupled to the stator group 2, and the housing 31 can directly or indirectly combine the permanent magnets. The magnet group 32 and the permanent magnet group 32 are also disposed toward the core 21 of the stator assembly 2. Thereby, when the motor of the second embodiment having the air purifying device is started, the stator group 2 will drive the permanent magnet group 32 to drive the rotor 3 to operate, so that the casing 31 rotates around the iron core 21, and The rotor motor is similar to the first embodiment. In other words, the motor of the present invention having an air purifying device can be an outer rotor motor or an inner rotor motor.

Referring to FIG. 5, a motor having an air purifying device according to a third embodiment of the present invention is different from the foregoing first embodiment in that the guide vane 33 is coupled to the housing 31 and faces away from the internal space. R extends in one direction. In detail, the housing 31 of the rotor 3 opens through a vent 311 of the internal space R. The first end edge 33a of the guide vane 33 is connected to the periphery of the vent 311, and the guide vane 33 is The first end edge 33a extends in a direction away from the circuit board 6 to the second end edge 33b.

Accordingly, when the stator assembly 2 drives the rotor 3 to operate, the rotation of the casing 31 of the rotor 3 will simultaneously drive the guide vanes 33 to rotate, and the air outside the casing 31 is transmitted through the rotation of the guide vanes 33. The vent 311 is introduced into the casing 31 to form an air flow flowing toward the internal space R of the motor. Compared with the foregoing first preferred embodiment, in the present embodiment, the guide vanes 33 are connected to extend away from one of the internal spaces R, thereby ensuring that the airflow generated by the rotation of the guide vanes 33 is all The housing 31 is externally introduced to maintain the number of electrically neutral molecules or oxygen molecules in the internal space R of the motor, thereby effectively increasing the efficiency of the air purification device 5 to generate negative ions or ozone molecules.

Referring to Figures 6 and 7, wherein FIG. 6 is a motor having an air purifying device according to a fourth embodiment of the present invention, and FIG. 7 is a schematic view showing the appearance of the iron core 21 of the motor having the air purifying device according to the fourth embodiment. . The difference from the foregoing first embodiment is that the iron core 21 of the stator assembly 2 defines a through hole 211 which penetrates the iron core 21 so that the air flow in the inner space R of the motor can be from the rotor 3 The guide vane 33 flows through the through hole 211 to the through hole 41 of the base 1. Thereby, the airflow generated by the guide vane 33 can pass through the through hole 211 of the iron core 21 to be discharged to the outer space of the motor through the through hole 41, and the airflow can be prevented from being received by the iron core 21 or the motor. The remaining members of the internal space R are hindered from flowing to the air flow passage 4.

In addition, in the embodiment, the circuit board 6 can be coupled to the stator assembly 2, and the air cleaning device 5 is electrically connected to the circuit board 6 to be coupled to the stator assembly 2, so that The emitting end 51 of the air cleaning device 5 can be disposed toward the guiding vane 33. Accordingly, the negative ions or ozone molecules formed in the vicinity of the emitter end 51 are driven by the airflow generated by the guide vanes 33 to pass through the through holes 211 of the core 21 and the through holes formed in the base 1 respectively. 41 is discharged to the external space of the motor.

According to the structural features disclosed above, the main features of the motor having the air purifying device of the first, second, third and fourth embodiments of the present invention are as follows: by coupling an air purifying device 5 to a base 1 or a stator Group 2, a guide vane 33 is disposed on a rotor 3, and an inner space R communicating with the motor and an air flow passage 4 of the outer space are provided, and the air flow passage 4 may include a through hole 41 opened in the base 1; or The inclusions are formed in a gap 42 between the base 1 and the rotor 3. The air purifying device 5 can generate negative ions or ozone molecules in the internal space R of the motor, and when the stator group 2 drives the rotor 3 to operate, the guiding vane 33 can rotate with the rotor 3 to the inside of the motor. The space R drives a flow of air that will drive the negative ions or the ozone molecules to exit the outer space of the motor via the air flow passage 4.

Therefore, it can be seen that the negative ion device 92 of the fan 9 having the air purifying device must be operated in conjunction with the motor connected to the fan wheel. The motor having the air purifying device of the present invention is provided with the guide vane 33 by the rotor 3. And providing an inner space R connecting the motor and an air flow passage 4 of the outer space, wherein the guide vane 33 can be used to drive the airflow in the inner space R of the motor to generate the negative ions generated by the air cleaning device 5. Or the ozone molecules are discharged to the outer space of the motor via the air flow passage 4. Accordingly, the motor having the air purifying device of the present invention does not need to be connected to the fan wheel, so that the negative ions generated by the air purifying device or the ozone molecules can be effectively diffused and propagated into the surrounding air to achieve the effect of purifying the air, so the motor is not required to be connected. The fan wheel can achieve the effect of purifying the air. It is suitable for various motor applications, effectively improving the functional diversity of the motor, and indeed has the effect of improving the practicality of the motor.

Furthermore, the negative ion loading of the fan 9 having the air purifying device is similar to that described above. The position 92 must be disposed at a position adjacent to the fan wheel of the fan, and is easily affected by the air flow at a position adjacent to the fan wheel, which causes the negative ion device 92 to ionize the nearby airflow to form a negative ion. The invention has an air purifying device. The air purifying device 5 of the motor may be coupled to the base 1 or the stator assembly 2, and the transmitting end 51 of the air purifying device 5 is disposed in the internal space R of the motor. According to this, even if the rotor 3 is connected to a fan wheel, the air in the outer space of the motor flows faster, and the transmitting end 51 located in the inner space R of the motor is still unaffected, and the negative electrode of the air purifying device 5 can be prevented from being generated. Or the action of the ozone molecules is affected by the airflow in the external space of the motor, ensuring that the efficiency of the negative ion or ozone molecules generated by the air purifying device 5 is stable, and indeed has the effect of enhancing the effect of purifying the air.

In summary, the motor with the air purifying device of the present invention can achieve the effects of improving the utility of the motor and improving the air purifying effect of the air purifying device.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

1‧‧‧Base

2‧‧‧stator group

21‧‧‧ iron core

22‧‧‧Exciting coil

3‧‧‧Rotor

31‧‧‧Shell

311‧‧‧ vents

32‧‧‧Permanent magnet set

33‧‧‧Guide vanes

33a‧‧‧First edge

33b‧‧‧second edge

4‧‧‧Air passage

41‧‧‧through hole

5‧‧‧Air purification device

51‧‧‧transmitter

6‧‧‧Circuit board

R‧‧‧Internal space

Claims (13)

A motor having an air purifying device, comprising: a certain subgroup, the stator assembly is coupled with a base; a rotor rotatably coupled to the stator assembly, the rotor is provided with a guide vane, and the base and the base The rotor surrounds an internal space, the stator assembly is disposed in the internal space, the rotor includes a housing rotatably coupled to the stator assembly, the housing and the base surround the internal space The guide vane has a first end edge and a second end edge, and the first end edge of the guide vane is coupled to the casing; an air flow passage connecting the internal space of the motor and a An external space; and an air purifying device coupled to the base or the stator assembly, and the air purifying device is provided with a transmitting end, and the emitting end is disposed in the inner space. The motor of the air purifying device of claim 1, wherein the air flow channel comprises a through hole, the through hole is defined in the base, and the through hole is penetrated through the base to respectively communicate with the motor Internal space and external space. A motor having an air purifying device according to claim 2, wherein the emitting end of the air purifying device is disposed toward the through hole. The motor having an air purifying device according to claim 1, wherein the air flow passage includes a gap formed between the housing of the rotor and the base to respectively communicate with the inside of the motor Space and exterior space. A motor having an air purifying device according to claim 4, wherein the emitting end of the air purifying device is disposed toward the gap. A motor having an air purifying device according to claim 1 of the patent application, wherein a circuit board is coupled to the base, the air purifying device is electrically connected to the circuit board, and the guide vane extends from the first end edge toward the circuit board to the second end edge . The motor having an air purifying device according to claim 1, wherein the casing opens a vent opening through the inner space, and the first end edge of the guide vane is connected to a periphery of the vent. The motor having an air purifying device according to claim 7, wherein the motor further comprises a circuit board, the circuit board is coupled to the base, and the air purifying device is electrically connected to the circuit board, and the guide vane is The first end edge extends in a direction away from one of the circuit boards to the second end edge. The motor having an air purifying device according to claim 1, wherein the stator assembly comprises an iron core, the iron core is received in a casing of the rotor, and the iron core has a through hole, and the through hole penetrates The iron core enables airflow in the interior space to flow from the guide vanes of the rotor to the airflow passage via the perforations. The motor of the air purifying device of claim 9, wherein the air flow channel comprises a through hole, the through hole is defined in the base, and the through hole is penetrated through the base to respectively communicate with the motor The inner space and the outer space penetrate the iron core such that airflow in the inner space can flow from the guide vane of the rotor to the through hole via the through hole. The motor having an air purifying device according to claim 9, wherein the motor further comprises a circuit board, the circuit board is coupled to the stator group, the air purifying device is electrically connected to the circuit board, and the air purifying device is The transmitting end is disposed toward the guiding vane. The motor having an air purifying device according to any one of claims 1 to 11, wherein the air purifying device is an negative ion generator for the transmitting end An negative ion is generated, and the guide vane is rotatable with the rotor to drive an air flow in the inner space of the motor, and the air flow will drive the negative ions to be discharged to the outer space of the motor via the air flow passage. The motor having an air purifying device according to any one of claims 1 to 11, wherein the air purifying device is an ozone generator for generating ozone molecules at the emitting end, the guiding vanes being capable of The rotor rotates to drive an air flow in the internal space of the motor, which will drive the ozone molecules to be discharged to the external space of the motor via the air flow passage.