Rear end dust-proof sealing motor for heat dissipation of radio transmitter

Abstract

This invention discloses a rear-end dustproof sealed motor for heat dissipation in a radio transmitter, comprising a housing, a main shaft, a rotor, and a stator. The housing has a front end cover and a rear end cover, respectively. The front end of the main shaft extends forward beyond the front end cover, and the rear end of the main shaft is rotatably connected to the rear end cover via a rear bearing. A dustproof sealing device for sealing the bearing chamber is provided on the front side of the rear end cover. The dustproof sealing device of this invention adopts a structure combining a double-lip skeleton oil seal and a shaped oil seal seat. It serves as a dustproof barrier for the bearing of the cooling fan in the transmitter's heat dissipation system, preventing grease contamination and providing double dust protection for the motor. This extends the motor's service life, improves fan utilization, and ensures the reliable operation of the transmitter's heat dissipation system.

Description

Technical Field

[0001] This invention belongs to the field of radio transmitter technology, and specifically relates to a dustproof and sealed motor for heat dissipation of a radio transmitter. Background Technology

[0002] As LEDs and electronic devices develop towards higher power, integration, and miniaturization, the heat generated by these power devices is increasing significantly. Therefore, heat dissipation is a primary challenge. If the heat generated by these materials is not dissipated in time, the junction temperature of the devices will rise, severely impacting their operational stability and lifespan. Polymer-based thermally conductive insulating materials can be applied between heat-generating and heat-dissipating devices, making them a key component in thermal management.

[0003] As the "heart" of a radio transmission system, the transmitter generates a significant amount of heat during operation due to its internal electrical components. Temperature has a substantial impact on the performance of these components; studies have shown that the reliability of power transistors decreases by 60% for every 10-degree Celsius increase in temperature. For high-power radio transmitters, the impact of temperature on performance is even more pronounced. The purpose of a broadcast transmitter cooling system is to achieve thermal reliability, ensuring that the system operates reliably and efficiently according to predetermined parameters.

[0004] The DX series medium-wave transmitters are the main application models of high-power medium-wave transmitters in my country. Based on the cooling method, they can be divided into water-cooled and air-cooled models. Although air cooling is less efficient than water cooling, it has advantages such as simple system structure, stability and reliability, economical operation, and easy maintenance, and has now become the mainstream model. The air-cooled DX series transmitters expand the heat dissipation area through field-effect power transistors and heat sinks, forcing air convection to remove the heat dissipated by the system body; it is a heat transfer process that involves both conduction and convection.

[0005] In an air-cooled heat dissipation system, the air source for cooling the transmitter is a cooling fan (a fan installed on the extension end of the motor spindle). The cooling fan is installed inside the transmitter. Both its front and rear end covers are designed as ventilation end covers with ventilation grilles. During operation, the fan located at the shaft extension end of the motor spindle draws cooling air into the transmitter through a filter to cool the internal components. At the same time, the motor also generates heat during operation. The fan blades installed inside the motor and located on the front side of the spindle can reverse the flow of the cool air drawn into the transmitter and draw it back into the motor to cool it down. The air is then discharged through the ventilation grille on the rear end cover. The bearings exposed in the bearing chamber of the rear end cover are blown in by the circulating air. Although the dust protection for the grease inside the bearings relies on the dust covers on both sides of the bearings, there is a gap between the dust covers and the bearing end faces. As the operating time increases, this gap will gradually increase. With the external strong air pressure cooling method, dust, oil fumes, water mist, steam, etc. will be carried into the transmitter by the airflow, which will greatly increase the probability that the grease inside the bearings will be contaminated by the dust contained in the circulating air.

[0006] The bearings are usually deep groove ball bearings, which do not have their own cleaning function and are particularly sensitive to the cleanliness of the circulating air. Once dust enters the grease, it will remain inside the grease. Contamination of the grease will greatly reduce the service life of the bearing, increase the bearing clearance, and generate vibration. This will cause radial runout and axial movement of the motor spindle during rotation, disrupting the normal working state of the fan. Consequently, the airflow speed and volume of the cooling air will decrease, affecting the normal heat dissipation of the transmitter, changing the stable temperature rise of the transmitter, and eventually leading to high-temperature failure.

[0007] Currently, the main technologies used in domestic and international air-cooled transmitter heat dissipation systems to address the dust prevention issue of the cooling fan drive motor include:

[0008] 1. Domestic transmitter manufacturers mostly use external rotor asynchronous motors. The overall structure of this type of motor is relatively sealed. The bearing between the main shaft and the end cover is sealed with a rubber seal ring. Since this technology does not have a forced lubrication device, dust in the heat dissipation circulating air can easily adhere to the surface of the rubber seal ring, accelerating the wear of the rubber seal ring. Dust will then enter the bearing chamber from the worn part of the rubber seal ring, contaminating the bearing grease and reducing the service life of the motor.

[0009] 2. Foreign transmitter manufacturers mostly use asynchronous motors with ventilation grilles on both the front and rear end covers. Their dust prevention is achieved by adding a dust filter sponge mesh to the rear end of the motor mounting bracket. The circulating air is drawn into the transmitter by the fan through the sponge filter mesh. However, the defect of the sponge filter mesh is that if the mesh is too thick, it will affect ventilation, and if it is too thin, it will not be conducive to dust prevention. Moreover, after long-term use, the elasticity of the sponge mesh decreases, and it can no longer filter the fine dust in the circulating air, thereby contaminating the grease of the motor bearings and reducing the service life of the motor. Summary of the Invention

[0010] In order to overcome the shortcomings of the prior art, the present invention provides a dustproof and sealed motor for heat dissipation of a radio transmitter that is simple in structure, tightly sealed, highly reliable, and not easily damaged.

[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a dustproof and sealed motor for heat dissipation of a radio transmitter, comprising a housing, a main shaft, a rotor, and a stator. The housing is cylindrical and open at both the front and rear ends. The front and rear ends of the housing are respectively provided with a front cover and a rear cover. Both the front cover and the rear cover are ventilation grille structures. The front end of the main shaft is rotatably connected to the front cover through a front bearing. The front end of the main shaft extends forward beyond the front cover. The rear end of the main shaft is rotatably connected to the rear cover through a rear bearing. The rotor is mounted on the main shaft. The stator is mounted on the inner wall of the housing and located outside the rotor. The main shaft is provided with fan blades located between the front cover and the rotor. The center of the rear cover is provided with a bearing chamber with an open front side. The outer circle of the rear bearing is assembled in the bearing chamber. The front side of the rear cover is provided with a dustproof and sealing device for sealing the bearing chamber.

[0012] The dustproof sealing device includes a shaped oil seal seat, a double-lip skeleton oil seal, and a sealing gasket. The shaped oil seal seat is pressed against the front opening of the bearing housing. The shaped oil seal seat is fixedly connected to the rear end cover by two bolt assemblies located outside the bearing housing. The sealing gasket is pressed between the rear side of the shaped oil seal seat and the front annular surface of the bearing housing. The shaped oil seal seat has a stepped hole that is open at the front and back in the center. The main shaft passes through the stepped hole coaxially. The double-lip skeleton oil seal is interference-fitted into the stepped hole and rotates and seals with the outer circle of the main shaft.

[0013] The irregularly shaped oil seal seat includes a ring-shaped seat body. An inner ring is provided on the rear side of the inner circle of the seat body to form the stepped hole in the center of the seat body. The outer circle of the seat body is provided with a first arc plate and a second arc plate. A first mounting hole for a bolt assembly is opened on the first arc plate, and a second mounting hole for a bolt assembly is opened on the second arc plate. The first mounting hole and the second mounting hole are symmetrical about the center line of the stepped hole in the center of the seat body. A positioning ring that mates with the outer circle of the front end of the bearing chamber is integrally provided on the rear side of the irregularly shaped oil seal seat.

[0014] The irregularly shaped oil seal seat is made of H62 brass, and the sealing gasket is made of asbestos board.

[0015] The rotor has several heat dissipation and ventilation holes that are open from left to right, and all the heat dissipation and ventilation holes are evenly arranged along the circumference of the main shaft.

[0016] Using the above technical solution, the working principle of this invention is as follows: A fan for cooling the internal components of the transmitter is installed at the front end of the main shaft extension. The fan blows air from back to front to cool the components in front of the motor. The rotation of the main shaft drives the fan blades inside the housing to rotate. The fan blades blow air from front to back. Air from outside the housing enters through the ventilation grille structure on the front cover, then flows backward through the heat dissipation vents inside the rotor, and finally exits through the ventilation grille structure on the rear cover. The process of airflow circulating inside the housing carries away the heat generated inside the motor, thereby cooling the motor.

[0017] To prevent dust contained in the cooling circulating air from threatening the rear bearing inside the motor and to extend the service life of the circulating cooling fan, a dustproof sealing device is installed on the exposed bearing surface on the front side of the rear end cover, so that the bearing chamber where the rear bearing is installed forms a sealed space.

[0018] The lip size of the double-lip skeleton oil seal in the dustproof sealing device is required to be coupled with the outer diameter of the spindle. It is installed in the stepped hole of the special-shaped oil seal seat, and together with the special-shaped oil seal seat, it covers the front side of the rear bearing and is fixed to the rear end cover with bolt assembly. The external structure of the special-shaped oil seal seat (the first arc plate and the second arc plate that are not connected) will not cover the original ventilation grille structure of the end cover, and will not affect the ventilation and heat dissipation of the motor. During installation, grease is applied between the two lips of the double-lipped oil seal, forming an oil film between the spindle and the seal lips. This improves the wear resistance of both the spindle and the seal, increasing their service life. However, the thick rubber skeleton wall hinders heat dissipation. To address this issue, the shaped oil seal seat is made of H62 brass, which is machinable, corrosion-resistant, and has good heat dissipation properties. This enhances its heat dissipation performance and prevents excessively high temperatures in the bearing chamber during motor operation, which could cause the grease inside the bearing to age and fail due to high temperatures. A sealing gasket made of asbestos board is placed at the mating surface between the shaped oil seal seat and the front annular surface of the bearing chamber. Asbestos board is heat-resistant and expands after being coated with grease, further improving the sealing of the mating surface and thus enhancing dust prevention.

[0019] Since the fan blades on the main shaft are located behind the front bearing, the circulating air inside the casing flows from front to back. Therefore, the circulating air passes through the front bearing in the opposite direction, so the front bearing does not need to be tightly sealed.

[0020] In summary, the dustproof sealing device of this invention adopts a structure combining a double-lip skeleton oil seal and a special-shaped oil seal seat. As a dustproof seal for the bearing of the cooling fan in the transmitter's heat dissipation system, it effectively solves the following problems: 1. When using an "O"-ring rubber seal for dustproof sealing, there are defects such as easy wear and short service life. 2. When using a sponge dustproof mesh, the sponge filter is prone to aging and damage, thus causing dustproof failure. The dustproof sealing device of this invention can effectively prevent dust from entering the bearing, avoid grease contamination, provide double dust protection for the motor, improve fan utilization, and ensure the reliable operation of the transmitter's heat dissipation system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0023] Figure 3 This is a plan view of an irregularly shaped oil seal seat;

[0024] Figure 4 yes Figure 3 BB section view. Detailed Implementation

[0025] like Figure 1-4 As shown, the dustproof sealed motor for heat dissipation of a radio transmitter of the present invention includes a housing 1, a main shaft 2, a rotor 7, and a stator 8. The housing 1 is cylindrical and open at both ends. The front and rear ends of the housing 1 are respectively provided with a front cover 3 and a rear cover 4. Both the front cover 3 and the rear cover 4 are ventilation grille structures 5. The front end of the main shaft 2 is rotatably connected to the front cover 3 through a front bearing 6. The front end of the main shaft 2 extends forward beyond the front cover 3. The rear end of the main shaft 2 is rotatably connected to the rear cover 4 through a rear bearing 9. The rotor 7 is mounted on the main shaft 2. The stator 8 is mounted on the inner wall of the housing 1 and located outside the rotor 7. The main shaft 2 is provided with fan blades 10 located between the front cover 3 and the rotor 7. The rear cover 4 has a bearing chamber 11 with an open front side at its center. The outer circle of the rear bearing 9 is assembled in the bearing chamber 11. The front side of the rear cover 4 is provided with a dustproof sealing device 12 for sealing the bearing chamber 11.

[0026] The dustproof sealing device 12 includes a shaped oil seal seat 13, a double-lip skeleton oil seal 14, and a sealing gasket 15. The shaped oil seal seat 13 is pressed onto the front opening of the bearing chamber 11. The shaped oil seal seat 13 is fixedly connected to the rear end cover 4 by two bolt assemblies 16 located outside the bearing chamber 11. The sealing gasket 15 is pressed between the rear side of the shaped oil seal seat 13 and the front annular surface of the bearing chamber 11. The shaped oil seal seat 13 has a stepped hole 17 that is open at the front and back. The main shaft 2 passes through the stepped hole 17 coaxially. The double-lip skeleton oil seal 14 is interference-fitted into the stepped hole 17 and rotates and seals with the outer circle of the main shaft 2.

[0027] The irregular oil seal seat 13 includes a ring-shaped seat body 18. An inner ring 24 is provided on the rear side of the inner circle of the seat body 18 so that the central hole of the seat body 18 forms the stepped hole 17. The outer circle of the seat body 18 is provided with a first arc plate 19 and a second arc plate 20. The first arc plate 19 has a first mounting hole 21 for passing through a bolt assembly 16, and the second arc plate 20 has a second mounting hole 22 for passing through a bolt assembly 16. The first mounting hole 21 and the second mounting hole 22 are symmetrical about the center line of the central stepped hole 17 of the seat body 18. The rear side of the irregular oil seal seat 13 is integrally provided with a positioning ring 23 that mates with the outer circle of the front end of the bearing chamber 11.

[0028] The irregularly shaped oil seal seat 13 is made of H62 brass, and the sealing gasket 15 is made of asbestos board.

[0029] The rotor 7 has several heat dissipation and ventilation holes 24 that are open from left to right, and all the heat dissipation and ventilation holes 24 are evenly arranged along the circumference of the main shaft 2.

[0030] The working principle of this invention is as follows: A fan for cooling the internal components of the transmitter is installed at the front end of the main shaft 2. The fan blows air from back to front to cool the components in front of the motor. The rotation of the main shaft 2 drives the fan blades 10 inside the housing 1 to rotate. The fan blades 10 blow air from front to back. The air outside the housing 1 enters through the ventilation grille structure 5 on the front cover 3, then flows backward through the heat dissipation vents 24 inside the rotor 7, and finally exits through the ventilation grille structure 5 on the rear cover 4. The process of airflow circulating inside the housing 1 carries away the heat generated inside the motor, thereby cooling the motor.

[0031] In order to prevent the dust contained in the cooling circulating air from threatening the rear bearing 9 inside the motor and to improve the service life of the circulating cooling fan, a dustproof sealing device 12 is installed on the exposed bearing surface on the front side of the rear end cover 4, so that the bearing chamber 11 where the rear bearing 9 is installed forms a sealed space.

[0032] The lip size of the double-lip skeleton oil seal 14 in the dustproof sealing device 12 is required to be coupled with the outer diameter of the spindle 2. It is installed in the stepped hole 17 of the irregular oil seal seat 13, and together with the irregular oil seal seat 13, it covers the front side of the rear bearing 9 and is fixed to the rear end cover 4 with bolt assembly 16. The external structure of the irregular oil seal seat 13 (the first arc plate 19 and the second arc plate 20 that are not connected) will not obstruct the original ventilation grille structure 5 of the end cover, and will not affect the ventilation and heat dissipation of the motor. During installation, grease is applied between the two lips of the double-lipped skeleton oil seal 14, forming an oil film between the spindle 2 and the oil seal lips. This improves the wear resistance of the spindle 2 and the oil seal, increasing their service life. However, the thick wall of the rubber skeleton hinders heat dissipation. To address this issue, the shaped oil seal seat 13 is made of H62 brass, which is machinable, corrosion-resistant, and has good heat dissipation properties. This enhances its heat dissipation performance and prevents the bearing chamber 11 from overheating during motor operation, which could cause the grease inside the bearing to age and fail due to high temperatures. A sealing gasket 15 made of asbestos board is placed at the mating surface between the shaped oil seal seat 13 and the front annular surface of the bearing chamber 11. Asbestos board is heat-resistant and expands in volume after being coated with grease, further enhancing the sealing of the mating surface and improving dust prevention.

[0033] Since the fan blades 10 on the main shaft 2 are located behind the front bearing 6, the circulating air inside the housing 1 flows from front to back. Therefore, the circulating air passes through the front bearing 6 in the opposite direction, so the front bearing 6 does not need to be tightly sealed.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dustproof sealed motor for heat dissipation of a radio transmitter, comprising a housing, a main shaft, a rotor, and a stator. The housing is cylindrical with openings at both the front and rear ends. A front cover and a rear cover are respectively provided at the front and rear ends of the housing. Both the front and rear covers are ventilation grille structures. The front end of the main shaft is rotatably connected to the front cover via a front bearing, and the front end of the main shaft extends forward beyond the front cover. The rear end of the main shaft is rotatably connected to the rear cover via a rear bearing. The rotor is mounted on the main shaft, and the stator is located on the inner wall of the housing and outside the rotor. Fan blades are provided on the main shaft between the front cover and the rotor. The motor is characterized by: The rear end cover has a bearing chamber with an open front side at its center. The outer circle of the rear bearing is assembled in the bearing chamber. The front side of the rear end cover has a dustproof sealing device for sealing the bearing chamber. The dustproof sealing device includes a special-shaped oil seal seat, a double-lip skeleton oil seal, and a sealing gasket. The special-shaped oil seal seat is pressed onto the front opening of the bearing housing. The special-shaped oil seal seat is fixedly connected to the rear end cover by two bolt assemblies located outside the bearing housing. The sealing gasket is pressed between the rear side of the special-shaped oil seal seat and the front annular surface of the bearing housing. The special-shaped oil seal seat has a stepped hole that is open at the front and rear. The main shaft passes through the stepped hole coaxially. The double-lip skeleton oil seal is interference-fitted into the stepped hole and rotates and seals with the outer circle of the main shaft. The irregularly shaped oil seal seat includes a ring-shaped seat body. An inner ring is provided on the rear side of the inner circle of the seat body to form the stepped hole in the center of the seat body. The outer circle of the seat body is provided with a first arc plate and a second arc plate. A first mounting hole for a bolt assembly is opened on the first arc plate, and a second mounting hole for a bolt assembly is opened on the second arc plate. The first mounting hole and the second mounting hole are symmetrical about the center line of the stepped hole in the center of the seat body. A positioning ring that mates with the outer circle of the front end of the bearing chamber is integrally provided on the rear side of the irregularly shaped oil seal seat.

2. The dustproof sealed motor for heat dissipation of a radio transmitter according to claim 1, characterized in that: The irregularly shaped oil seal seat is made of H62 brass, and the sealing gasket is made of asbestos board.

3. The dustproof sealed motor for heat dissipation of a radio transmitter according to claim 1 or 2, characterized in that: The rotor has several heat dissipation and ventilation holes that are open from left to right, and all the heat dissipation and ventilation holes are evenly arranged along the circumference of the main shaft.

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