A structure for internal ventilation of an electric machine and protection of rotor bearings

Abstract

The application relates to a kind of ventilation and rotor bearing protection structure for motor inside, including the end cover being arranged in the one side of base, the middle part of the end cover is equipped with opening, the lower part of the opening is used to install rotor bearing, the rotor bearing is matched with the end part of rotor shaft, the base is further provided with exhaust mechanism, the exhaust mechanism is used to discharge hot air in the inside of base from the air outlet on the base;Bearing protection cover is installed in the inside of the base, one side of the bearing protection cover is connected with the end cover, the other side of the bearing protection cover is provided with the perforation sealed with the rotor shaft, the middle part of the bearing protection cover forms bearing accommodating cavity, the part of rotor bearing located in the inside of end cover is accommodated in the bearing accommodating cavity, the bearing accommodating cavity is communicated with the outside of motor.Thereby, the influence of hot air in motor on rotor bearing is reduced, and the design requirement of ventilation structure in the inside of motor is reduced.

Description

Technical Field

[0001] This invention relates to the field of motor structure technology, and in particular to a structure for internal ventilation and rotor bearing protection in motors. Background Technology

[0002] The design of the motor fan structure and rotor bearings is crucial. An inadequate fan ventilation structure can cause hot air to re-enter the core cavity, leading to poor heat dissipation. When the bearings are exposed to hot air, the bearing temperature can become excessively high, triggering an alarm and causing the motor to shut down.

[0003] With increasingly stringent cost requirements in motor design, the increased power density of motors leads to higher temperatures of the cooling gas passing through the fan. Since a significant portion of the rotor bearing is typically embedded deep within the motor, this part of the structure is subjected to hot air blowing from inside the motor, causing a sharp rise in bearing temperature that is difficult to mitigate even with forced lubrication structures. Summary of the Invention

[0004] In response to the shortcomings of the existing production technology, the applicant provides a structure for internal ventilation and rotor bearing protection in motors, thereby reducing the impact of hot air inside the motor on the rotor bearings and reducing the design requirements of the internal ventilation structure of the motor.

[0005] The technical solution adopted in this invention is as follows:

[0006] A structure for internal ventilation and rotor bearing protection of an electric motor includes an end cover disposed on one side of the motor base. The end cover has an opening in the middle, and the lower part of the opening is used for mounting a rotor bearing, which mates with the end of a rotor shaft.

[0007] The base is also provided with an exhaust mechanism, which is used to exhaust the hot air inside the base to the air outlet on the base.

[0008] The base is equipped with a bearing protective cover. One side of the bearing protective cover is connected to the end cover. The other side of the bearing protective cover is provided with a through hole that seals with the rotor shaft. The middle part of the bearing protective cover forms a bearing receiving cavity. The part of the rotor bearing located inside the end cover is accommodated in the bearing receiving cavity. The bearing receiving cavity is connected to the outside of the motor.

[0009] Its further technical solution lies in:

[0010] The bearing protective cover includes a cover body with a rotating housing structure. One end of the cover body is open and connected to the end cap. The other end of the cover body is closed and has the through hole in the center. The center of the through hole is located on the axis of the cover body. The exhaust mechanism is installed on the rotor shaft. The exhaust mechanism is a centrifugal fan. The through hole is located between the rotor bearing and the exhaust mechanism.

[0011] The cover includes a straight pipe section with a circular cross-section. One end of the straight pipe section is provided with a folded edge, which is detachably connected to the end cap by fasteners. The other end of the straight pipe section is closed by a flat plate. The center of the flat plate is provided with a sealing part with an annular structure. The inner ring of the sealing part is the through hole. The flat plate cooperates with the side of the exhaust mechanism.

[0012] An outlet baffle is provided inside the base. One side of the outlet baffle cooperates with the exhaust mechanism, and the other side of the outlet baffle cooperates with the outer periphery of the stator coil inside the base. The outlet baffle is used to prevent hot air from the air outlet from returning to the inside of the base.

[0013] The exhaust mechanism has an air inlet baffle on its air inlet side. The air inlet baffle has a cylindrical structure and is concentrically arranged with the exhaust mechanism. The outer circumferential surface of the air inlet baffle is matched with the end of the outlet baffle. The outlet baffle and the air inlet baffle are used to prevent hot air at the air outlet from returning to the machine base.

[0014] The axial distance between the exhaust mechanism and the end of the outlet baffle is greater than the allowable axial movement distance of the rotor bearing.

[0015] The outlet wind deflector is made of insulating material.

[0016] An exhaust baffle is provided on the leeward side of the exhaust mechanism. The exhaust baffle is a cylindrical structure and is sleeved on the outer periphery of the straight pipe section. The inner diameter of the exhaust baffle is larger than the outer diameter of the straight pipe section.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention has a compact and reasonable structure and is easy to operate. By installing a bearing protective cover inside the base, the rotor bearing is separated from the hot air flowing by the exhaust mechanism, thereby reducing the impact of hot air inside the motor on the rotor bearing and reducing the design requirements of the internal ventilation structure of the motor.

[0019] Furthermore, the present invention also has the following advantages:

[0020] (1) The bearing protective cover separates the internal space of the machine base into a bearing housing cavity that is isolated from the hot air inside the machine base. This eliminates the cover plate installed on the bearing in the prior art to block the opening. The bearing housing cavity is connected to the outside of the motor through the upper space of the rotor bearing. The bearing housing cavity is used for heat dissipation of the rotor bearing, avoiding the direct blowing of hot air on the rotor bearing, reducing the bearing temperature, reducing the possibility of bearing oil leakage, and facilitating the maintenance of the rotor bearing. Even if an oil leakage problem occurs, it will be blocked outside the machine base 1 by the bearing protective cover, avoiding contamination of the core iron core and coil of the motor and causing problems with the whole machine.

[0021] (2) The outer wall of the rotating shell structure serves as a guide structure, which helps the hot air to be discharged from the air outlet under the centrifugal force of the exhaust mechanism.

[0022] (3) The end of the outlet baffle plate is radially matched with the inlet baffle plate to avoid the problem of large axial clearance in the original structure, which causes hot air to return to the machine base from the axial clearance, thus improving the working efficiency and heat dissipation effect of the exhaust mechanism.

[0023] (4) The exhaust baffle works in conjunction with the straight pipe section to block the hot air from the exhaust side of the exhaust mechanism from entering the airless cavity, thereby reducing the pressure change and heat radiation inside the airless cavity and reducing the impact on the sealing effect of the perforation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the bearing protective cover of the present invention.

[0026] Figure 3 This is a schematic diagram of the exhaust mechanism, air inlet baffle, and exhaust baffle of the present invention.

[0027] The components include: 1. Base; 101. Air outlet; 2. End cover; 201. Opening; 3. Rotor bearing; 4. Rotor shaft; 5. Exhaust mechanism; 501. Inlet baffle; 502. Exhaust baffle; 6. Bearing protective cover; 601. Perforation; 602. Straight pipe section; 603. Flat plate; 604. Sealing part; 605. Folded edge; 7. Motor top cover; 8. Outlet baffle; 9. Stator coil;

[0028] A. Receiving cavity; B. Airless cavity; C. Heat exchange cavity; D. Exhaust cavity. Detailed Implementation

[0029] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0030] Example 1:

[0031] like Figure 1 , Figure 2 As shown, the internal ventilation and rotor bearing protection structure of this embodiment includes an end cover 2 disposed on one side of the base 1. The end cover 2 has an opening 201 in the middle. The lower part of the opening 201 is used to install the rotor bearing 3. The rotor bearing 3 is engaged with the end of the rotor shaft 4.

[0032] The base 1 is also equipped with an exhaust mechanism 5, which is used to exhaust the hot air inside the base 1 to the air outlet 101 on the base 1.

[0033] The base 1 is equipped with a bearing protective cover 6. One side of the bearing protective cover 6 is connected to the end cover 2. The other side of the bearing protective cover 6 is provided with a through hole 601 that seals with the rotor shaft 4. The middle part of the bearing protective cover 6 forms a bearing receiving cavity A. The part of the rotor bearing 3 located inside the end cover 2 is accommodated in the bearing receiving cavity A. The bearing receiving cavity A is connected to the outside of the motor.

[0034] Specifically, the conventional frame 1 has a removable end cover 2 on its side. The end cover 2 serves as the mounting reference for the rotor shaft 4 and is used to mount the rotor bearing 3. The rotor bearing 3 rotatably supports the rotor shaft 4. Typically, the rotor bearing 3 can be an oil-cooled bearing or a grease-lubricated rolling bearing. A large part of the bearing extends deep into the motor, i.e., ... Figure 1 As shown, the part of the rotor bearing 3 located inside the end cover 2 is located inside the end cover 2; the exhaust mechanism 5 is used to draw the cold air from the motor top cover 7 into the machine base 1, and to make the cold air exchange heat with the stator and rotor of the motor to form hot air that is discharged from the air outlet 101, thereby reducing the temperature of the motor body.

[0035] In this embodiment, a bearing protective cover 6 is provided to separate the internal space of the base 1 into a bearing receiving cavity A that is isolated from the hot air inside the base 1. This eliminates the cover plate installed on the bearing in the prior art to block the opening 201. The bearing receiving cavity A is connected to the outside of the motor through the upper space of the rotor bearing 3. The bearing receiving cavity A is used for heat dissipation of the rotor bearing 3, avoiding direct blowing of hot air onto the rotor bearing 3, reducing the temperature of the bearing, reducing the possibility of bearing oil leakage, and facilitating the maintenance of the rotor bearing 3. Even if an oil leakage problem occurs, it will be blocked outside the base 1 by the bearing protective cover 6, preventing the core iron core and coil of the motor from being contaminated and causing problems with the whole machine.

[0036] In the prior art, the conventional exhaust mechanism 5 is a centrifugal fan installed on the rotor shaft 4. The fan's air intake direction is along the fan axis, and the fan's exhaust direction is along the tangential direction of the fan's outer periphery. In this embodiment, after setting the bearing protective cover 6 to separate the rotor bearing 3 from the hot air, the exhaust mechanism 5 can be a fan installed on the base 1 to draw out the hot air from the air outlet 101. The exhaust mechanism 5 can also be an axial flow fan installed on the rotor shaft 4, which expands the selection range of the exhaust mechanism 5 and reduces the requirements for the fan in the ventilation structure.

[0037] By installing a bearing guard 6 inside the base 1, the rotor bearing 3 is separated from the hot air flowing by the exhaust mechanism 5, thereby reducing the impact of the hot air inside the motor on the rotor bearing 3 and reducing the design requirements of the internal ventilation structure of the motor.

[0038] Example 2:

[0039] Based on Embodiment 1, the exhaust mechanism 5 is selected as a centrifugal fan. In order to make the gas flow path inside the base 1 more reasonable, this embodiment further improves the ventilation inside the motor and the rotor bearing protection structure.

[0040] It should be pointed out first that for the centrifugal fan type exhaust mechanism 5, the air intake side of the fan is the air intake side of the exhaust mechanism 5, and the opposite side is the leeward side. Due to centrifugal force, the air drawn into the fan is discharged from the outer periphery of the fan, which is the exhaust side.

[0041] like Figure 1 , Figure 2 As shown, the bearing protective cover 6 includes a cover body with a rotating shell structure. One end of the cover body is open and connected to the end cover 2, and the other end of the cover body is closed and has a through hole 601 in the center. The center of the through hole 601 is located on the axis of the cover body. An exhaust mechanism 5 is installed on the rotor shaft 4. The exhaust mechanism 5 is a centrifugal fan. The through hole 601 is located between the rotor bearing 3 and the exhaust mechanism 5.

[0042] Specifically, the open end of the cover can be welded to the end cap 2 or detachably connected, such as with a stop fit; the outer wall of the cover with the rotating shell structure serves as a guide structure, which helps the hot air to be discharged from the air outlet 101 under the centrifugal force of the exhaust mechanism 5.

[0043] Furthermore, such as Figure 1 , Figure 2 As shown, the cover includes a straight pipe section 602 with a circular cross-section. One end of the straight pipe section 602 is provided with a folded edge 605. The folded edge 605 is detachably connected to the end cap 2 by fasteners. The other end of the straight pipe section 602 is closed by a flat plate 603. The center of the flat plate 603 is provided with a sealing part 604 with an annular structure. The inner ring of the sealing part 604 is a perforation 601. The flat plate 603 cooperates with the side of the exhaust mechanism 5.

[0044] Specifically, the combination of the circular straight pipe section 602 and the flat plate 603 makes the structure of the bearing protective cover 6 more compact. The side of the flat plate 603 corresponds to the leeward side of the exhaust mechanism 5, and the distance between the side of the flat plate 603 and the leeward side of the exhaust mechanism 5 can be closer, making the volume of the windless cavity B formed between the small bearing protective cover 6 and the exhaust mechanism 5 smaller.

[0045] Furthermore, such as Figure 1 As shown, an outlet baffle 8 is provided inside the base 1. One side of the outlet baffle 8 cooperates with the exhaust mechanism 5, and the other side of the outlet baffle 8 cooperates with the outer periphery of the stator coil 9 inside the base 1. The outlet baffle 8 is used to prevent hot air at the air outlet 101 from returning to the inside of the base 1.

[0046] Specifically, the outlet baffle 8 forms a ring-shaped structure with a central opening inside the base 1. The central opening corresponds to the air inlet side of the exhaust mechanism 5 and is used to prevent hot air from the air outlet side of the exhaust mechanism 5 from returning to the base 1.

[0047] Typically, the rotor bearing 3 uses an oil-cooled bearing or a grease-lubricated rolling bearing. This type of bearing structure generally has an axial runout dimension of 10mm-20mm. Therefore, the exhaust mechanism 5 and the outlet baffle 8 cannot be designed too close together, otherwise friction will occur. This will inevitably cause some air to re-enter the core cavity, affecting the heat dissipation effect and the working efficiency of the exhaust mechanism 5.

[0048] Furthermore, such as Figure 1 , Figure 3 As shown, an air inlet baffle 501 is provided on the air inlet side of the exhaust mechanism 5. The air inlet baffle 501 has a cylindrical structure and is concentrically arranged with the exhaust mechanism 5. The outer circumferential surface of the air inlet baffle 501 is matched with the end of the outlet baffle 8. The outlet baffle 8 and the air inlet baffle 501 are used to prevent hot air at the air outlet 101 from returning to the machine base 1.

[0049] Specifically, as the exhaust mechanism 5 rotates, the end of the outlet baffle 8 has a certain gap with the outer circumferential surface of the inlet baffle 501. The end of the outlet baffle 8 is radially fitted with the inlet baffle 501, avoiding the problem of large axial clearance in the original structure, which caused hot air to return to the machine base 1 through the axial clearance, thus improving the working efficiency and heat dissipation effect of the exhaust mechanism 5.

[0050] Furthermore, such as Figure 1 As shown, the axial distance between the exhaust mechanism 5 and the end of the outlet baffle 8 is greater than the allowable axial movement distance of the rotor bearing 3.

[0051] Based on the structure of the radial fit between the ends of the air inlet baffle 501 and the outlet baffle 8, sufficient design margin can be set for the axial distance between the exhaust mechanism 5 and the ends of the outlet baffle 8.

[0052] Furthermore, the export wind deflector 8 is made of insulating material.

[0053] Specifically, the outlet baffle 8 of the insulating material can be closer to the motor coil to reduce the size of the motor, while allowing as much of the air drawn in by the exhaust mechanism 5 as possible to pass through the coil, forcing the cooling gas to pass through the gaps between the coils and improving the heat dissipation effect.

[0054] Furthermore, such as Figures 1-3 As shown, an exhaust baffle 502 is provided on the leeward side of the exhaust mechanism 5. The exhaust baffle 502 is a cylindrical structure and is sleeved on the outer periphery of the straight pipe section 602. The inner diameter of the exhaust baffle 502 is larger than the outer diameter of the straight pipe section 602.

[0055] Specifically, the exhaust baffle 502 works in conjunction with the straight pipe section 602 to prevent hot air from the exhaust side of the exhaust mechanism 5 from entering the interior of the airless cavity B, thereby reducing pressure changes and heat radiation inside the airless cavity B, reducing the impact on the sealing effect at the perforation 601, and thus reducing the sealing requirements for the sealing part 604. The sealing part 604 can be selected from sealing structures such as skeleton seals and oil seals.

[0056] In the above structure: the outlet baffle 8, the inlet baffle 501, and the air inlet side of the exhaust mechanism 5 form a heat exchange chamber C with the inside of the base 1; the outlet baffle 8, the inlet baffle 501, the exhaust baffle 502, and the exhaust side of the exhaust mechanism 5 form an exhaust chamber D with the inside of the base 1. The hot air in the heat exchange chamber C is discharged from the exhaust chamber D to the air outlet 101 after passing through the exhaust mechanism 5. The windless chamber B has basically no hot air entering it. The bearing housing chamber A is isolated from the windless chamber B and the exhaust chamber D by the bearing protective cover 6, so that the rotor bearing 3 is not affected by the hot air in the base 1.

[0057] The working principle of this embodiment is as follows:

[0058] like Figure 1 The diagram shown is an overall structural schematic of the motor internal ventilation and rotor bearing protection structure used in this embodiment, as well as an airflow schematic.

[0059] After the cold air enters the motor base 1, it forms hot air in the heat exchange chamber C inside the base 1. The hot air enters the exhaust chamber D through the exhaust mechanism 5 and enters the motor top cover 7 on the upper part of the base 1 through the air outlet 101.

[0060] The outlet baffle 8 and the inlet baffle 501 work together to prevent hot air from re-entering the heat exchange chamber C;

[0061] The exhaust baffle 502 works in conjunction with the straight pipe section 602 to prevent hot air from entering the windless chamber B, so that the windless chamber B is not affected by wind pressure, ensuring the isolation effect of the bearing protective cover 6 on the bearing housing cavity A, thereby preventing the bearing housing cavity A from being affected by wind pressure and heat, avoiding the direct blowing of hot air on the rotor bearing 3, and reducing the heat generation problem of the rotor bearing 3.

[0062] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A structure for internal ventilation and rotor bearing protection of an electric motor, comprising an end cover (2) disposed on one side of a base (1), wherein the end cover (2) has an opening (201) in the middle, and the lower part of the opening (201) is used for mounting a rotor bearing (3), wherein the rotor bearing (3) cooperates with the end of a rotor shaft (4), characterized in that: The base (1) is also provided with an exhaust mechanism (5), which is used to exhaust the hot air inside the base (1) to the air outlet (101) on the base (1). The base (1) is equipped with a bearing guard (6). One side of the bearing guard (6) is connected to the end cover (2). The other side of the bearing guard (6) is provided with a through hole (601) that seals with the rotor shaft (4). The middle part of the bearing guard (6) forms a bearing receiving cavity (A). The part of the rotor bearing (3) located inside the end cover (2) is accommodated in the bearing receiving cavity (A). The bearing receiving cavity (A) is connected to the outside of the motor. The bearing protective cover (6) includes a cover body with a rotating housing structure. One end of the cover body is open and connected to the end cap (2). The other end of the cover body is closed and the perforation (601) is provided in the center. The center of the perforation (601) is located on the axis of the cover body. The exhaust mechanism (5) is installed on the rotor shaft (4). The exhaust mechanism (5) is a centrifugal fan. The perforation (601) is located between the rotor bearing (3) and the exhaust mechanism (5). The cover includes a straight pipe section (602) with a circular cross-section. One end of the straight pipe section (602) is provided with a folded edge (605). The folded edge (605) is detachably connected to the end cap (2) by fasteners. The other end of the straight pipe section (602) is closed by a flat plate (603). The center of the flat plate (603) is provided with a sealing part (604) with an annular structure. The inner ring of the sealing part (604) is the perforation (601). The flat plate (603) cooperates with the side of the exhaust mechanism (5). An outlet baffle (8) is provided inside the base (1). One side of the outlet baffle (8) cooperates with the exhaust mechanism (5), and the other side of the outlet baffle (8) cooperates with the outer periphery of the stator coil (9) inside the base (1). The outlet baffle (8) is used to block the hot air at the air outlet (101) from returning to the inside of the base (1). The exhaust mechanism (5) is provided with an air inlet baffle (501) on the air inlet side. The air inlet baffle (501) is a cylindrical structure. The air inlet baffle (501) is concentrically arranged with the exhaust mechanism (5). The outer circumferential surface of the air inlet baffle (501) is matched with the end of the outlet baffle (8). The outlet baffle (8) and the air inlet baffle (501) are used to block the hot air at the air outlet (101) from returning to the machine base (1).

2. The structure for internal ventilation and rotor bearing protection of an electric motor as described in claim 1, characterized in that: The axial distance between the exhaust mechanism (5) and the end of the outlet baffle (8) is greater than the allowable axial movement distance of the rotor bearing (3).

3. The structure for internal ventilation and rotor bearing protection of an electric motor as described in claim 1, characterized in that: The outlet wind deflector (8) is made of insulating material.

4. The structure for internal ventilation and rotor bearing protection of an electric motor as described in claim 1, characterized in that: The exhaust mechanism (5) has an exhaust baffle (502) on its leeward side. The exhaust baffle (502) is a cylindrical structure and is sleeved on the outer periphery of the straight pipe section (602). The inner diameter of the exhaust baffle (502) is larger than the outer diameter of the straight pipe section (602).

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