Low-speed direct-drive permanent magnet synchronous motor for cement mixer

Abstract

The utility model discloses a cement mixer used low speed direct drive permanent magnet synchronous motor, comprising a housing, a main shaft, a permanent magnet rotor, a stator, a front end cover, a rear end cover, a fan housing and a fan, the rotating joint of the main shaft and the front end cover and the rotating joint of the main shaft and the rear end cover are respectively provided with a first bearing, and the two sides of the first bearing are respectively provided with a sealing gland. The sealing glands on the two sides are connected with the front end cover / the rear end cover in a penetrating mode through first bolt assemblies, and sealing rings are arranged at the rotating connecting positions of the sealing glands and the main shaft. According to the utility model, through the arrangement of the sealing glands and the sealing rings, the main shaft and the two ends of the bearing are sealed, external dust or moisture can be effectively prevented from entering the motor along a gap between the main shaft and the bearing, and further through the arrangement of the positioning plate, the permanent magnet rotor is sealed, so that the service life of the motor is prolonged. Therefore, the dustproof and moistureproof performance of the motor is obviously improved, the working stability of the motor is improved, and the service life of the motor is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a low-speed direct-drive permanent magnet synchronous motor for cement mixers. Background Technology

[0002] Currently, the drive units used in cement mixers generally consist of ordinary AC motors and reducers, sometimes requiring additional gears, chains, or belts for transmission. For example, the drive structure disclosed in patent CN219902729U, a cement mixer for construction engineering, includes a motor, a reduction gear, a drive gear, and a gear ring. This drive structure suffers from drawbacks such as complex structure, high power consumption, and poor dust and moisture resistance. Construction site conditions are typically harsh, and ordinary AC motors are prone to dust and moisture ingress, causing varying degrees of damage.

[0003] 1. When the inside of the motor gets damp, the insulation material will be damaged, which increases the risk of short circuit and damage to the motor. When it rotates, it may cause the circuit to smoke or even burn, resulting in a serious accident.

[0004] Second, moisture can cause the magnets of a motor to rust, leading to a decrease in magnetic force, which in turn affects the motor's power output and power consumption.

[0005] Third, dust entering the motor bearing will accelerate bearing wear, leading to poor lubrication, increased friction, and increased noise;

[0006] Fourth, dust can also accumulate on the surface of the heat sink and cooling fan, reducing heat dissipation efficiency and causing the motor to overheat.

[0007] Fifth, dust will further absorb moisture, causing the insulation material to become damp and increasing the risk of short circuits.

[0008] To solve the above problems, the applicant tried different types of motors and finally found that permanent magnet synchronous motors have significant advantages such as low speed and high torque, simple structure, low power consumption, low noise and high reliability. They are very suitable as the drive device for cement mixers. Furthermore, due to the low speed and high torque characteristics of permanent magnet synchronous motors, there is no need to set up additional transmission structures such as reducers, gears, belts or chains, and direct drive of cement mixers can be achieved.

[0009] In addition, considering the working conditions of cement mixers, the permanent magnet synchronous motor also needs to be dustproofed and moisture-proofed to solve the problems of motor working stability and service life. Utility Model Content

[0010] To achieve the above objectives, this utility model discloses a low-speed direct-drive permanent magnet synchronous motor for a cement mixer, comprising a housing, a main shaft, a permanent magnet rotor, a stator, a front end cover, a rear end cover, a fan shroud, and a fan. The main shaft is axially disposed within the housing, and the permanent magnet rotor is coaxially disposed outside the main shaft. The stator is disposed on the inner wall of the housing and located outside the permanent magnet rotor. The front end cover and the rear end cover are respectively radially disposed at the front and rear ends of the housing. The two ends of the main shaft extend to the outer sides of the front end cover and the rear end cover, respectively. The fan shroud is disposed on the rear side of the housing, and the fan is disposed inside the fan shroud and coaxially connected to the main shaft. A first bearing is provided at the rotational connection between the main shaft and the front end cover and the rear end cover. Sealing caps are provided on both sides of the first bearings. The sealing caps on both sides are connected to the front end cover / rear end cover through a first bolt assembly. Sealing rings are provided at the rotational connection between the sealing caps and the main shaft.

[0011] Furthermore, the outer wall of the main shaft and the inner wall of the permanent magnet rotor are provided with multiple keyways along the axial direction. The multiple keyways are equidistantly distributed along the circumferential direction, and each keyway is provided with a key block.

[0012] Furthermore, a front positioning plate is provided radially on the main shaft at the position in front of the permanent magnet rotor, and a rear positioning plate is provided radially on the main shaft at the position behind the permanent magnet rotor. The center hole of the rear positioning plate is threaded to the outer wall of the main shaft, and the front positioning plate and the rear positioning plate are connected by a second bolt assembly.

[0013] Furthermore, both the front positioning plate and the rear positioning plate are provided with several ventilation holes.

[0014] Furthermore, a second bearing is provided inside the sealing cap on one side of the rear end cover. The second bearing is sleeved on the outside of the main shaft and is arranged adjacent to the first bearing.

[0015] Furthermore, the outer wall of the housing is provided with multiple oil inlets at positions corresponding to the sealing cap, each oil inlet is provided with an oil inlet pipe, the sealing cap is provided with an oil inlet channel, and the end of the oil inlet pipe is threadedly connected to the oil inlet channel.

[0016] Furthermore, the oil injection pipe has a movable groove at one end outside the housing, a limiting groove inside the movable groove, a ball inside the movable groove, and a spring inside the limiting groove. The spring extends into the movable groove and presses the ball against the opening of the oil injection pipe.

[0017] Furthermore, the first bearing is a deep groove ball bearing, and the second bearing is a thrust roller bearing.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] This invention seals both ends of the main shaft and bearings by using a sealing cap and sealing ring, effectively preventing external dust or moisture from entering the motor through the gap between the main shaft and bearings. Furthermore, the permanent magnet rotor is sealed by the positioning plate, which significantly improves the motor's dustproof and moisture-proof performance, enhances the motor's working stability, and helps extend its service life. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0022] Figure 2 This is an axial structural cross-sectional view of the present invention;

[0023] Figure 3 This is a schematic diagram of the internal end face structure of this utility model;

[0024] Figure 4 for Figure 2 Enlarged view of the local structure at point A;

[0025] Figure 5 for Figure 2 Enlarged view of the local structure at point B.

[0026] Figure label:

[0027] 1-House, 2-Main shaft, 3-Permanent magnet rotor, 4-Stator, 5-Front end cover, 6-Rear end cover, 7-Fan shroud, 8-Fan, 9-First bearing, 10-Sealing gland, 11-First bolt assembly, 12-Sealing ring, 13-Second bearing, 14-Key block, 15-Front positioning plate, 16-Rear positioning plate, 17-Second bolt assembly, 18-Ventilation hole, 19-Oil inlet, 20-Oil inlet pipe, 21-Oil inlet channel, 22-Moving groove, 23-Limiting groove, 24-Ball bearing, 25-Spring. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0029] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0030] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0031] In the description of the embodiments, unless otherwise expressly specified and limited, the terms "set," "connect," etc., should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or a connection through an intermediate medium, or it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] like Figure 1-2 As shown, the cement mixer in this embodiment uses a low-speed direct-drive permanent magnet synchronous motor, which includes a housing 1, a main shaft 2, a permanent magnet rotor 3, a stator 4, a front cover 5, a rear cover 6, a fan shroud 7, and a fan 8. The main shaft 2 is axially arranged inside the housing 1, the permanent magnet rotor 3 is coaxially arranged outside the main shaft 2, the stator 4 is arranged on the inner wall of the housing 1 and located outside the permanent magnet rotor 3, the front cover 5 and the rear cover 6 are respectively radially arranged at the front and rear ends of the housing 1, the two ends of the main shaft 2 extend to the outside of the front cover 5 and the rear cover 6, the fan shroud 7 is arranged on the rear side of the housing 1, and the fan 8 is arranged inside the fan shroud 7 and coaxially connected to the main shaft 2.

[0033] The main shaft 2 is provided with a first bearing 9 at the rotational connection between the front end cover 5 and the rear end cover 6. The first bearing 9 is provided with a sealing cover 10 on both sides. The sealing cover 10 on both sides is connected to the front end cover 5 / rear end cover 6 through the first bolt assembly 11. The sealing cover 10 is provided with a sealing ring 12 at the rotational connection between the main shaft 2 and the sealing cover 2.

[0034] By setting the sealing gland 10 and the sealing ring 12, the two ends of the main shaft 2, the first bearing 9 and the second bearing 13 are sealed, which can effectively prevent external dust or moisture from entering the motor through the gap between the main shaft 2 and the bearing. This significantly improves the motor's dustproof and moisture-proof performance, enhances the motor's working stability, and helps extend its service life.

[0035] A second bearing 13 is also provided inside the sealing cover 10 on one side of the rear end cover 6. The second bearing 13 is sleeved on the outside of the main shaft 2 and is arranged adjacent to the first bearing 9.

[0036] Among them, the first bearing 9 is a deep groove ball bearing, and the second bearing 13 is a thrust roller bearing.

[0037] Multiple keyways are provided along the axial direction on the outer wall of the main shaft 2 and the inner wall of the permanent magnet rotor 3. The multiple keyways are equidistantly distributed along the circumferential direction. Each keyway is provided with a key block 14. Through the cooperation of the key block 14 and the keyway, the permanent magnet rotor 3 and the main shaft 2 are positioned in the circumferential direction. The permanent magnet rotor 3 can drive the main shaft 2 to rotate.

[0038] A front positioning plate 15 is provided radially on the main shaft 2 at the front side of the permanent magnet rotor 3, and a rear positioning plate 16 is provided radially on the rear side of the main shaft 2 at the rear side of the permanent magnet rotor 3. The center hole of the rear positioning plate 16 is threaded to the outer wall of the main shaft 2. The front positioning plate 15 and the rear positioning plate 16 are connected by a second bolt assembly 17. By setting the front positioning plate 15 and the rear positioning plate 16, the permanent magnet rotor 3 and the main shaft 2 can be positioned in the axial direction.

[0039] like Figure 3 As shown, both the front positioning plate 15 and the rear positioning plate 16 are provided with several ventilation holes 18. The front positioning plate 15 and the rear positioning plate 16 have certain dustproof and waterproof effects, while the ventilation holes 18 can also ensure the ventilation and heat dissipation of the permanent magnet rotor 3.

[0040] Multiple oil inlets 19 are provided on the outer wall of the housing 1 at positions corresponding to the sealing gland 10, and each oil inlet 19 is provided with an oil inlet pipe 20, such as... Figure 4 As shown, the sealing gland 10 is provided with an oil injection channel 21, and the end of the oil injection pipe 20 is threadedly connected to the oil injection channel 21. Lubricating oil can be injected into the sealing gland 10 through the oil injection pipe 20. After the lubricating oil enters the sealing gland 10, it contacts the main shaft 2, the first bearing 9, and the second bearing 13 inside it, thereby achieving rotational lubrication.

[0041] like Figure 5 As shown, the oil injection pipe 20 has a movable groove 22 at one end located outside the housing 1. A limiting groove 23 is provided inside the movable groove 22. A ball bearing 24 is provided inside the movable groove 22. A spring 25 is provided inside the limiting groove 23. The spring 25 extends into the movable groove 22 and presses the ball bearing 24 against the opening of the oil injection pipe 20.

[0042] When lubrication is required, the ball 24 is pressed inward by the oil injector to open the pipe opening, and the lubricating oil can enter the sealing gland 10 along the oil injection pipe 20. After the oil injection is completed, the ball 24 is re-blocked by the spring 25, so as to achieve the injection of lubricating oil without damaging the seal.

[0043] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope claimed by this utility model.

Claims

1. A low-speed direct-drive permanent magnet synchronous motor for a cement mixer, comprising a housing, a main shaft, a permanent magnet rotor, a stator, a front cover, a rear cover, a fan shroud, and a fan, wherein the main shaft is axially disposed within the housing, the permanent magnet rotor is coaxially disposed outside the main shaft, the stator is disposed on the inner wall of the housing and located outside the permanent magnet rotor, the front cover and the rear cover are respectively radially disposed at the front and rear ends of the housing, the two ends of the main shaft extend to the outer sides of the front cover and the rear cover, respectively, the fan shroud is disposed on the rear side of the housing, and the fan is disposed inside the fan shroud and coaxially connected to the main shaft, characterized in that: The main shaft is provided with a first bearing at the rotatable connection between the main shaft and the front and rear covers. A sealing cover is provided on both sides of the first bearing. The sealing cover on both sides is connected to the front / rear cover through a first bolt assembly. A sealing ring is provided at the rotatable connection between the sealing cover and the main shaft.

2. The low-speed direct-drive permanent magnet synchronous motor for a cement mixer according to claim 1, characterized in that: The outer wall of the main shaft and the inner wall of the permanent magnet rotor are provided with multiple keyways along the axial direction. The multiple keyways are equidistantly distributed along the circumferential direction, and each keyway is provided with a key block.

3. The low-speed direct-drive permanent magnet synchronous motor for a cement mixer according to claim 1, characterized in that: A front positioning plate is provided radially on the main shaft at the position in front of the permanent magnet rotor, and a rear positioning plate is provided radially on the main shaft at the position behind the permanent magnet rotor. The center hole of the rear positioning plate is threaded to the outer wall of the main shaft, and the front positioning plate and the rear positioning plate are connected by a second bolt assembly.

4. The low-speed direct-drive permanent magnet synchronous motor for a cement mixer according to claim 3, characterized in that: Both the front and rear positioning plates are provided with several ventilation holes.

5. The low-speed direct-drive permanent magnet synchronous motor for a cement mixer according to claim 1, characterized in that: A second bearing is also provided inside the sealing cover on one side of the rear end cover. The second bearing is sleeved on the outside of the main shaft and is arranged adjacent to the first bearing.

6. The low-speed direct-drive permanent magnet synchronous motor for a cement mixer according to claim 1, characterized in that: The outer wall of the housing is provided with multiple oil inlets corresponding to the sealing cap. Each oil inlet is provided with an oil inlet pipe. The sealing cap is provided with an oil inlet channel. The end of the oil inlet pipe is threadedly connected to the oil inlet channel.

7. The low-speed direct-drive permanent magnet synchronous motor for a cement mixer according to claim 6, characterized in that: The oil injection pipe has a movable groove at one end outside the housing. A limiting groove is provided inside the movable groove. A ball is provided in the movable groove. A spring is provided in the limiting groove. The spring extends into the movable groove and presses the ball against the opening of the oil injection pipe.

8. The low-speed direct-drive permanent magnet synchronous motor for a cement mixer according to claim 5, characterized in that: The first bearing is a deep groove ball bearing, and the second bearing is a thrust roller bearing.

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