External rotor motor structure with eccentric block

Abstract

This utility model discloses an external rotor motor structure with an eccentric block, including an external rotor assembly, an inner stator assembly, and a fixed base. The inner stator assembly is fixedly installed on the fixed base, and the external rotor assembly is sleeved on the inner stator assembly. A motor shaft is fixed on the external rotor assembly, and the motor shaft passes through the inner stator assembly and the fixed base. The motor shaft rotates with the external rotor assembly. An eccentric block located on one side of the fixed base is fixed on the motor shaft. The eccentric block and the motor shaft are integrally formed. By making the eccentric block and the motor shaft an integrally formed structure, the connection structure between the eccentric block and the motor shaft is eliminated, thereby reducing the height of the motor structure with the eccentric block in the direction of the motor shaft axis. This results in a smaller volume when assembled into the machine housing, reducing the machine size. The external rotor motor has a larger rotating area than the inner rotor motor, which facilitates heat dissipation.

Description

Technical Field

[0001] This utility model relates to an electric motor, and more particularly to an external rotor motor structure with an eccentric block. Background Technology

[0002] Currently, in order to achieve the eccentric movement of the tool head, power tools connect an eccentric block to the motor shaft, and then mount the tool head on the eccentric block. The eccentric block drives the tool head to move eccentrically. For example, in dry grinders or sanders, the high-frequency eccentric vibration of the eccentric block drives the grinding disc to move eccentrically for grinding.

[0003] For example, patent CN218194374U discloses a braking structure for a dry grinding mill disc, including a housing, a drive motor installed in the housing, and a grinding disc that vibrates at high frequency driven by the drive motor. The drive motor has a threaded joint on its lower transmission shaft, and an eccentric block has a threaded hole. The eccentric block is threadedly connected to the drive shaft through the threaded hole. The lower inner side of the eccentric block has a mounting hole that is not concentric with the center line of the drive motor transmission shaft. A bearing is fixedly installed inside the mounting hole, and an output shaft is fixedly installed inside the bearing. The grinding disc is fixedly connected to the lower end of the output shaft by screws.

[0004] The existing eccentric block and the motor shaft are two independent components. The connection between the eccentric block and the shaft requires a connection structure between them. For example, a threaded hole is provided on the eccentric block and a threaded connector is provided on the shaft. The eccentric block is threaded to the shaft through the threaded hole. The connection structure between the eccentric block and the shaft will increase the height of the whole assembly of the motor and eccentric block on the motor axis, thus requiring more space to be occupied when the whole assembly is installed in the power tool housing, thereby increasing the size of the machine. Utility Model Content

[0005] Based on the above-mentioned problem that the eccentric block and the motor shaft are two independent parts, and the assembly formed by their connection will increase the height on the motor axis due to the connection structure, thereby increasing the size of the machine, this utility model provides an external rotor motor structure with an eccentric block.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is: an external rotor motor structure with an eccentric block, including an external rotor assembly, an inner stator assembly and a fixed base. The inner stator assembly is fixedly installed on the fixed base, and the external rotor assembly is sleeved outside the inner stator assembly. When the external rotor assembly rotates, an eccentric block located on one side of the fixed base is fixed on the motor shaft. The eccentric block and the motor shaft are integrally formed.

[0007] A further preferred embodiment of this utility model is as follows: a housing is fixedly installed on the fixed base, and a cavity for accommodating the outer rotor assembly and the inner stator assembly is formed between the housing and the fixed base.

[0008] A further preferred embodiment of this utility model is as follows: an adapter is fixedly connected to the outer rotor assembly, and the motor shaft is fixedly connected to the adapter.

[0009] A further preferred technical solution of this utility model is as follows: the adapter is a circular cover installed on the rear side of the outer rotor assembly, the center of the circular cover is provided with a connecting seat, the center of the connecting seat is provided with a first through hole, the motor shaft passes through the first through hole and is fixedly connected to the connecting seat by screws.

[0010] A further preferred technical solution of this utility model is as follows: the connecting seat is provided with a threaded hole opened in its radial direction, the circular cover is provided with an assembly groove opened in its radial direction, one end of the assembly groove penetrates the outer circumferential surface of the circular cover, the threaded hole is located on the other end of the assembly groove, the threaded hole is connected to the first through hole, and the screw threaded in the threaded hole fixes the motor shaft and the connecting seat.

[0011] A further preferred embodiment of this utility model is as follows: the top surface of the circular cover is provided with a plurality of assembly grooves evenly distributed along the circumference, and the connecting seat is provided with the same number of threaded holes as the assembly grooves.

[0012] A further preferred technical solution of this utility model is as follows: the eccentric block is located on the front side of the fixed base, and a raised central cylinder is provided on the rear side of the fixed base. The inner stator assembly has a second through hole at its center. The inner stator assembly is fitted onto the central cylinder through the second through hole. The central cylinder has an axially penetrating channel for the motor shaft to pass through. The channel includes a first channel, a second channel, and a third channel with different diameters. The second channel is located between the first channel and the third channel, and its inner diameter is smaller than that of the first channel and the third channel. The second channel is transitioned to the first channel and the third channel by a step. The third channel located on the front side contains a front bearing. The outer ring of the front bearing is connected to the inner wall of the third channel and abuts against the step. The eccentric block has a first boss on the side facing the channel. The first boss abuts against the inner ring of the front bearing. The first channel located on the rear side contains a rear bearing. The outer ring of the rear bearing is connected to the inner wall of the first channel and abuts against the step. The connecting seat has a second boss on the side facing the channel. The second boss abuts against the inner ring of the rear bearing.

[0013] A further preferred embodiment of this utility model is that the fixed base is provided with several heat sinks on the front side near the eccentric block.

[0014] A further preferred embodiment of this utility model is that the lower end of the eccentric block has a mounting hole that is not concentric with the axis of the motor shaft.

[0015] A further preferred technical solution of this utility model is as follows: an annular groove is provided on the rear end of the motor shaft passing through the first through hole, and a retaining spring is engaged in the annular groove, with the retaining spring limited to the rear side of the connecting seat.

[0016] Compared with the prior art, the advantage of this utility model is that by setting the eccentric block and the motor shaft of the motor as an integrally formed structure, the connecting structure between the eccentric block and the motor shaft is eliminated, thereby reducing the height of the motor structure with the eccentric block in the direction of the motor shaft axis, thus occupying a smaller volume when assembled into the housing and reducing the size of the machine.

[0017] An external rotor motor has a larger rotating area than an internal rotor motor, which facilitates heat dissipation. Attached Figure Description

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the present invention. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ; Figure 3 This is a cross-sectional view of the present invention; Figure 4 This is a schematic diagram showing the separation of the outer casing and the mounting base. Figure 5 This is a structural schematic diagram of the adapter; Figure 6 Schematic diagram of the fixed base Figure 1 ; Figure 7 Schematic diagram of the fixed base Figure 2 .

[0020] In the diagram: 1. Outer shell; 2. Eccentric block; 3. Fixed base; 4. Heat sink; 5. Mounting hole; 6. Axis centerline; 7. Cavity; 8. Outer rotor assembly; 9. Adapter; 10. First through hole; 11. Annular groove; 12. Inner stator assembly; 13. Second through hole; 14. Second boss; 15. First channel; 16. Central cylinder; 17. First boss; 18. Motor shaft; 19. Third channel; 20. Front bearing; 21. Second channel; 22. Rear bearing; 23. Connecting ring; 24. Second connecting protrusion; 25. Connecting bolt; 26. Circular cover; 27. Connecting seat; 28. Assembly groove; 29. ​​Second threaded hole; 30. Step; 31. First connecting protrusion; 32. Through hole. Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that these descriptions are merely descriptive and exemplary and should not be construed as limiting the scope of protection of the present invention.

[0022] It should be noted that similar labels in the following figures indicate similar items; therefore, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

[0023] Figures 1-7 As shown, the external rotor motor structure with eccentric block includes an external rotor assembly 8, an inner stator assembly 12 and a fixed base 3. The inner stator assembly 12 is fixedly installed on the fixed base 3, and the external rotor assembly 8 is sleeved on the inner stator assembly 12. The external rotor assembly 8 can rotate relative to the inner stator assembly 12 to output rotational power. This structure is the conventional structure of existing external rotor motors.

[0024] Figure 3 As shown, a motor shaft 18 is fixed on the outer rotor assembly 8. The motor shaft 18 passes through the inner stator assembly 12 and the fixed base 3. The motor shaft 18 rotates with the outer rotor assembly 8. An eccentric block 2 located on one side of the fixed base 3 is fixed on the motor shaft 18. The eccentric block 2 is integrally formed with the motor shaft 18. The outer rotor assembly 8 outputs power through the motor shaft 18.

[0025] This patent sets the eccentric block 2 and the motor shaft 18 of the motor as an integral structure, eliminating the connection structure between the eccentric block 2 and the motor shaft 18. This reduces the height of the motor structure with the eccentric block 2 connected in the direction of the axis 6 of the motor shaft 18, thereby reducing the space occupied when assembled into the housing and making the machine smaller.

[0026] An external rotor motor has a larger rotating area than an internal rotor motor, which facilitates heat dissipation.

[0027] Figure 2 As shown, the lower end of the eccentric block 2 is provided with a mounting hole 5 that is not concentric with the axis 6 of the motor shaft 18. The mounting hole 5 can be used to install the tool head of the power tool.

[0028] Figure 4As shown, a housing 1 is fixedly installed on the fixed base 3. A cavity 7 is formed between the housing 1 and the fixed base 3 to accommodate the outer rotor assembly 8 and the inner stator assembly 12. The outer rotor assembly 8 and the inner stator assembly 12 are installed in the cavity 7. By combining the housing 1 with the fixed base 3, the outer rotor assembly 8 and the inner stator assembly 12 are both enclosed, so that the outer rotor motor structure is assembled into a whole. When assembling into the housing of the power tool, this whole can be placed directly into the housing of the power tool, without having to assemble the outer rotor assembly 8, inner stator assembly 12 and other components one by one in the housing of the power tool, which facilitates the installation of the outer rotor motor structure.

[0029] Multiple first connecting protrusions 31 are evenly provided on the outer circumferential surface of the fixed base 3, and corresponding second connecting protrusions 24 are provided on the outer circumferential surface of the outer shell 1. The first connecting protrusions 31 are provided with through holes 32, and the second connecting protrusions 24 are provided with first threaded holes. The connecting bolts 25 pass through the through holes 32 and are threadedly connected to the first threaded holes to fix the outer shell 1 and the fixed base 3 together.

[0030] A connecting ring 23 is fitted on the outer side of the outer casing 1. The connecting ring 23 is fixedly connected to each of the second connecting protrusions 24. There is a gap between the connecting ring 23 and the outer side wall of the outer casing 1.

[0031] Several heat sinks 4 are provided on the front side of the fixed base 3 near the eccentric block 2. The heat sinks 4 are used to accelerate the dissipation of heat from the cavity 7. The heat sinks 4 are distributed around the circumference of the fixed base 3.

[0032] An adapter 9 is fixedly connected to the outer rotor assembly 8, and the motor shaft 18 is fixedly connected to the adapter 9.

[0033] The adapter 9 is a circular cover 26 installed on the rear side of the outer rotor assembly 8. The center of the circular cover 26 is provided with a connecting seat 27. The center of the connecting seat 27 is provided with a first through hole 10. The rear end of the motor shaft 18 passes through the first through hole 10 and is fixedly connected to the connecting seat 27 by screws.

[0034] Figure 5 As shown, specifically, the connecting seat 27 is provided with a second threaded hole 29 opened radially therein, and the circular cover 26 is provided with an assembly groove 28 opened radially therein. One end of the assembly groove 28 penetrates the outer circumferential surface of the circular cover 26, and the second threaded hole 29 is located on the other end of the assembly groove 28. The second threaded hole 29 is connected to the first through hole 10. A screw threaded into the second threaded hole 29 fixes the motor shaft 18 and the connecting seat 27 together. The assembly groove 28 is provided to facilitate the insertion of the screw.

[0035] For example, a screw is screwed into the first through hole 10 and pressed against the side wall of the motor shaft 18 to fix the motor shaft 18 and the connecting seat 27 together; or a slot is opened on the motor shaft 18, and a screw is screwed into the first through hole 10 and inserted into the slot to fix the motor shaft 18 and the connecting seat 27 together.

[0036] The top surface of the circular cover 26 is provided with a plurality of mounting grooves 28 evenly distributed along the circumference, and the connecting seat 27 is provided with the same number of second threaded holes 29 as the mounting grooves 28. Preferably, the top surface of the circular cover 26 is provided with three mounting grooves 28 evenly distributed, and the connecting seat 27 is provided with three second threaded holes 29.

[0037] The eccentric block 2 is located on the front side of the fixed base 3. A raised central cylinder 16 is provided on the rear side of the fixed base 3. A second through hole 13 is provided at the center of the inner stator assembly 12. The inner stator assembly 12 is fitted onto the central cylinder 16 through the second through hole 13. The central cylinder 16 has an axially penetrating channel for the motor shaft 18 to pass through. The channel includes a first channel 15, a second channel 21, and a third channel 19. The second channel 21 is located between the first channel 15 and the third channel 19, and its inner diameter is smaller than that of the first channel 15 and the third channel 19. The second channel 21 and the first channel 15... The first and third channels 19 are connected by a step 30. The front bearing 20 is installed in the third channel 19 located on the front side. The outer ring of the front bearing 20 is connected to the inner wall of the third channel 19 and abuts against the step 30. The eccentric block 2 has a first boss 17 on the side facing the channel. The first boss 17 abuts against the inner ring of the front bearing 20. The rear bearing 22 is installed in the first channel 15 located on the rear side. The outer ring of the rear bearing 22 is connected to the inner wall of the first channel 15 and abuts against the step 30. The connecting seat 27 has a second boss 14 on the side facing the channel. The second boss 14 abuts against the inner ring of the rear bearing 22.

[0038] The structure connects the outer rotor assembly 8, the adapter 9, the motor shaft 18, the inner stator assembly 12, and the fixed base together.

[0039] An annular groove 11 is provided on the rear end of the motor shaft 18 that passes through the first through hole 10. A retaining spring is engaged in the annular groove 11. The retaining spring is positioned on the rear side of the connecting seat 27, which helps to limit the axial movement of the connecting seat 27 relative to the motor shaft 18, so as to make the connection structure more stable. It also makes it easier to fix the motor shaft 18 and the connecting seat 27 together with screws during installation.

[0040] The external rotor motor structure with eccentric block provided by this utility model has been described above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand this utility model and its core ideas. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. An external rotor motor structure with an eccentric block, comprising an external rotor assembly, an inner stator assembly, and a fixed base, wherein the inner stator assembly is fixedly mounted on the fixed base, and the external rotor assembly is sleeved around the inner stator assembly, characterized in that, The outer rotor assembly has a motor shaft fixed on it. The motor shaft passes through the inner stator assembly and the fixed base. The motor shaft rotates with the outer rotor assembly. An eccentric block located on one side of the fixed base is fixed on the motor shaft. The eccentric block is integrally formed with the motor shaft.

2. The external rotor motor structure with eccentric block according to claim 1, characterized in that, The fixed base is fixedly mounted with a housing, and a cavity is formed between the housing and the fixed base to accommodate the outer rotor assembly and the inner stator assembly.

3. The external rotor motor structure with eccentric block according to claim 1 or 2, characterized in that, An adapter is fixedly connected to the outer rotor assembly, and the motor shaft is fixedly connected to the adapter.

4. The external rotor motor structure with eccentric block according to claim 3, characterized in that, The adapter is a circular cover installed on the rear side of the outer rotor assembly. The center of the circular cover is provided with a connecting seat, and the center of the connecting seat is provided with a first through hole. The motor shaft passes through the first through hole and is fixedly connected to the connecting seat by screws.

5. The external rotor motor structure with eccentric block according to claim 4, characterized in that, The connecting seat is provided with a threaded hole that is opened radially thereon. The circular cover is provided with an assembly groove that is opened radially thereon. One end of the assembly groove passes through the outer circumference of the circular cover. The threaded hole is located on the other end of the assembly groove and is connected to the first through hole. The screw threaded in the threaded hole fixes the motor shaft and the connecting seat.

6. The external rotor motor structure with eccentric block according to claim 5, characterized in that, The circular cover has multiple mounting slots evenly distributed circumferentially on its top surface, and the connecting seat has the same number of threaded holes as the mounting slots.

7. The external rotor motor structure with eccentric block according to claim 4, characterized in that, The eccentric block is located on the front side of the fixed base. A raised central cylinder is provided on the rear side of the fixed base. The inner stator assembly has a second through hole in its center. The inner stator assembly is fitted onto the central cylinder through the second through hole. The central cylinder has an axially penetrating channel for the motor shaft to pass through. The channel includes a first channel, a second channel, and a third channel. The second channel is located between the first and third channels and has a smaller inner diameter than the first and third channels. The second channel is transitioned to the first and third channels by a step. The front bearing is installed in the third channel located on the front side. The outer ring of the front bearing is connected to the inner wall of the third channel and abuts against the step. A first boss is provided on the side of the eccentric block facing the channel. The first boss abuts against the inner ring of the front bearing. A rear bearing is installed in the first channel located on the rear side. The outer ring of the rear bearing is connected to the inner wall of the first channel and abuts against the step. A second boss is provided on the side of the connecting seat facing the channel. The second boss abuts against the inner ring of the rear bearing.

8. The external rotor motor structure with eccentric block according to claim 1, characterized in that, The fixed base has several heat sinks on the front side near the eccentric block.

9. The external rotor motor structure with eccentric block according to claim 1, characterized in that, The lower end of the eccentric block has a mounting hole that is not concentric with the axis of the motor shaft.

10. The external rotor motor structure with eccentric block according to claim 7, characterized in that, An annular groove is provided on the rear end of the motor shaft that passes through the first through hole. A retaining spring is engaged in the annular groove and is limited to the rear side of the connecting seat.

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