Brushless motor

Abstract

The utility model discloses a brushless motor, which comprises a shell, a rear cover, a central shaft and a circuit board, and is characterized in that the shell is cylindrical around an axis, and a coil is mounted on the inner wall of the shell. The rear cover is connected with the bottom end of the shell, and the top surface of the rear cover is provided with an installation protrusion. The center shaft is located in the shell, a magnet is installed outside the center shaft, the top end of the center shaft is rotationally connected with the shell, and the bottom end of the center shaft is rotationally connected with the rear cover. The circuit board is provided with an installation gap sleeved on the installation protrusion, the circuit board is provided with a Hall element patch, and the Hall element patch is located below the magnet and matched with the magnet to detect rotation of the center shaft.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a brushless motor. Background Technology

[0002] Existing brushless motors include a central shaft, magnets, coils, and a housing, with the magnets connected to the central shaft and the coils connected to the housing. The magnets and coils work together to drive the central shaft to rotate.

[0003] To detect the rotation angle of the central shaft, a Hall element is also needed to detect the central shaft. However, the Hall element needs to be precisely aligned with the magnet of the central shaft, otherwise it will easily affect the detection results. This places higher demands on the assembly of the brushless motor, leading to increased assembly costs. Summary of the Invention

[0004] The purpose of this invention is to provide a brushless motor to solve the problems of the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides a brushless motor, the brushless motor comprising:

[0006] The outer casing is cylindrical about an axis and has coils installed on its inner wall;

[0007] The rear cover is connected to the bottom end of the outer shell and has a mounting protrusion on its top surface;

[0008] A central shaft, located inside the housing and externally fitted with a magnet, the top end of the central shaft being rotatably connected to the housing and the bottom end being rotatably connected to the rear cover; and

[0009] The circuit board has a mounting notch that fits onto the mounting protrusion, and the circuit board has a Hall element patch located below the magnet and cooperating with the magnet to detect the rotation of the central shaft.

[0010] In one embodiment, the brushless motor further includes an insulating plate located between the rear cover and the circuit board and having a clearance notch for avoiding the mounting protrusion.

[0011] In one embodiment, the mounting protrusion is located at the edge of the rear cover;

[0012] The mounting notch opens radially outward toward the circuit board.

[0013] In one embodiment, the two mounting protrusions are symmetrical with respect to the axis.

[0014] The circuit board has two mounting notches that respectively engage with the two mounting protrusions.

[0015] In one embodiment, the radially outer side of the rear cover is further provided with a protruding annular step;

[0016] The bottom end of the outer shell abuts against the top end of the annular step and is connected to the annular step.

[0017] In one embodiment, the top end of the central shaft is rotatably connected to the housing via a bearing, and the bottom end is rotatably connected to the rear cover via another bearing.

[0018] In one embodiment, the brushless motor further includes two counterweights located inside the housing and connected to the bottom and top ends of the central shaft, respectively.

[0019] In one embodiment, the brushless motor further includes:

[0020] An inner magnetic yoke, wherein the inner magnetic yoke is looped around the radially outer side of the central axis and located radially inside the magnet;

[0021] An outer magnetic yoke is connected to the inner wall of the outer casing and is located radially outside the coil.

[0022] In one embodiment, the inner magnetic yoke comprises multiple layers of silicon steel sheets stacked along the axial direction of the central axis.

[0023] In one embodiment, the outer magnetic yoke comprises multiple layers of silicon steel sheets stacked along the axial direction of the central axis. Attached Figure Description

[0024] Figure 1 This is an assembly diagram of a brushless motor and transmission mechanism according to an embodiment of this utility model.

[0025] Figure 2 yes Figure 1 Assembly diagram of the brushless motor in the illustrated embodiment.

[0026] Figure 3 yes Figure 2 Top view of the brushless motor in the illustrated embodiment.

[0027] Figure 4 yes Figure 3 A cross-sectional view of the brushless motor along line AA in the embodiment shown.

[0028] Figure 5 , Figure 6 and Figure 7 They are Figure 3 An exploded view of the brushless motor in the illustrated embodiment.

[0029] Figure 8 yes Figure 5The assembly diagram of the back cover, insulating plate and circuit board in the embodiment shown.

[0030] Figure 9 and Figure 10 They are Figure 5 A perspective view of the back cover in the illustrated embodiment.

[0031] Figure 11 yes Figure 1 An exploded view of the brushless motor in the illustrated embodiment.

[0032] Figure 12 yes Figure 1 A perspective view of the outer casing and front cover in the illustrated embodiment.

[0033] Reference numerals: 100, brushless motor; 1, housing; 11, coil; 12, outer yoke; 13, front cover; 14, first mounting slot; 2, rear cover; 21, second mounting slot; 22, mounting protrusion; 23, wire hole; 24, rounded corner structure; 25, step; 26, annular gap; 3, central shaft; 31, magnet; 32, inner yoke; 4, circuit board; 41, mounting notch; 42, clearance hole; 43, Hall element patch; 5, insulating plate; 51, clearance notch; 6, counterweight; 7, bearing; 8, transmission mechanism; Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this utility model to facilitate a better understanding of this application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0035] Unless the context requires otherwise, throughout the specification and claims, the word “comprising” and its variations, such as “including” and “having”, shall be understood to have an open, inclusive meaning, that is, to be interpreted as “including, but not limited to”.

[0036] The embodiments of this utility model will be described in detail below with reference to the accompanying drawings to provide a clearer understanding of the purpose, features, and advantages of this utility model. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of this utility model, but are merely illustrative of the essential spirit of the technical solution of this utility model.

[0037] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0038] The singular forms “a” and “the” used in this specification and the appended claims include plural references unless otherwise expressly stated herein. It should be noted that the term “or” is generally used to mean “and / or” unless otherwise expressly stated herein.

[0039] In the following description, in order to clearly demonstrate the structure and working method of this utility model, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and not as limiting terms.

[0040] This utility model relates to a brushless motor 100, such as Figure 1-6 As shown, the brushless motor 100 includes a housing 1, a rear cover 2, a central shaft 3, a circuit board 4, a magnet 31 ringed around the outside of the central shaft 3, a coil 11 installed on the inner wall of the housing 1, an inner magnetic yoke 32, an outer magnetic yoke 12, an insulating plate 5, two counterweights 6 and two bearings 7. The housing 1 is a cylindrical shape extending around an axis. A front cover 13 is installed at the top of the housing 1, and the bottom end is connected to the rear cover 2 to form a receiving space.

[0041] The central shaft 3 extends along the axial direction and is located within the receiving space. The top end of the central shaft 3 is rotatably connected to the front cover 13 and extends to the outside of the front cover 13, where it is connected to an external transmission mechanism 8. The bottom end of the central shaft 3 is rotatably connected to the rear cover 2. In a specific embodiment, the front cover 13 has a first mounting groove 14 for mounting one of the bearings 7, while the rear cover 2 has a second mounting groove 21 for mounting the other bearing 7. The top and bottom ends of the central shaft 3 are respectively connected to the two bearings 7.

[0042] In addition, the top surface of the back cover 2 is provided with a protruding mounting protrusion 22. The circuit board 4 is stacked on the top surface of the back cover 2 and is provided with a mounting notch 41 that fits into the mounting protrusion 22. The circuit board 4 is provided with a Hall element patch 43, which is located below the magnet 31 and cooperates with the magnet 31 to detect the rotation angle of the central axis 3.

[0043] In other words, the mounting protrusion 22 is fitted into the mounting notch 41 to ensure that the Hall element patch 43 is aligned with the magnet 31. The mounting protrusion 22 and the mounting notch 41 serve a positioning function to ensure the positioning and installation of the circuit board 4.

[0044] The insulating plate 5 is located on the top surface of the back cover 2 and the bottom surface of the circuit board 4, that is, it is sandwiched between the back cover 2 and the circuit board 4, and the insulating plate 5 serves as insulation. The insulating plate 5 and the circuit board 4 are respectively provided with clearance holes 42 to avoid the central shaft 3, and the clearance holes 42 are aligned with the second mounting groove 21.

[0045] The insulating plate 5 is also provided with a clearance notch 51 to avoid affecting the positioning and assembly of the mounting protrusion 22 and the mounting notch 41.

[0046] exist Figure 3 and Figure 4 In the illustrated embodiment, two mounting protrusions 22 are respectively disposed at the edge of the rear cover 2, that is, on the radially outer side near the top surface of the rear cover 2, and the two mounting protrusions 22 are symmetrically arranged with respect to the center of the rear cover 2, that is, axially symmetrically arranged as described above. The circuit board 4 is provided with two mounting notches 41, which are respectively open to the radially outer side of the circuit board 4, and the two mounting protrusions 22 are respectively located within the two mounting notches 41.

[0047] Two clearance notches 51 are also provided at the edge of the insulating plate 5, which respectively avoid two mounting protrusions 22.

[0048] In a preferred embodiment, the rear cover 2 is further provided with a protruding annular step 25 on its radially outer side. The annular step 25 surrounds the radially outer side of the rear cover 2, and the top surface of the annular step 25 is lower than the top surface of the rear cover 2. The bottom end of the outer shell 1 abuts against the radially outer side of the rear cover 2 and against the top end of the annular step 25. The bottom end of the outer shell 1 and the annular step 25 can be fixedly connected by adhesive.

[0049] Both counterweights 6 are located inside the outer casing 1. One counterweight 6 is looped around the top of the central shaft 3 and located between the front cover 13 and the magnet 31, with the counterweight 6 spaced apart from the front cover 13. The other counterweight 6 is looped around the bottom of the central shaft 3 and located between the circuit board 4 and the magnet 31, with the counterweight 6 spaced apart from the circuit board 4 and the Hall element patch 43 on it.

[0050] The inner magnetic yoke 32 is looped around the radially outer side of the central shaft 3 and located radially inside the magnet 31. The inner magnetic yoke 32 fits against the radially outer side of the central shaft 3, while the magnet 31 wraps around the radially outer side of the inner magnetic yoke 32. Preferably, the inner magnetic yoke 32 comprises multiple layers of silicon steel sheets stacked along the axial direction of the central shaft 3. Each silicon steel sheet is annular and has the same inner and outer diameters. The multiple layers of silicon steel sheets, after being stacked, form a cylindrical shape that fits around the central shaft 3.

[0051] The outer magnetic yoke 12 is connected to the inner wall of the outer casing 1 and is located radially outside the coil 11. The outer magnetic yoke 12 extends around the radial inner wall of the outer casing 1 to form a ring, while the coil 11 extends around the radial inner side of the outer magnetic yoke 12. Preferably, the outer magnetic yoke 12 comprises multiple layers of silicon steel sheets stacked along the axial direction of the central axis 3.

[0052] A connection line is provided between the circuit board 4 and the coil 11, and the coil 11 is powered through the connection line. After the coil 11 is powered, the magnet 31, the inner yoke 32 and the central shaft 3 rotate to drive the brushless motor 100.

[0053] To ensure monitoring effectiveness, the position of the Hall element patch 43 needs to be aligned with the position of the magnet 31 during assembly. Specifically, the rising or falling edge of the U-phase Hall output signal needs to be aligned with the starting point of the back EMF of the U-phase coil 11. Therefore, the position of the Hall element patch 43 needs to be adjusted during assembly. A mounting notch 41 is provided on the edge of the circuit board 4. An insulating plate 5 is provided between the circuit board 4 and the back cover 2. The insulating plate 5 has a clearance notch 51 corresponding to the mounting notch 41. A mounting protrusion 22 corresponding to the mounting notch 41 is provided at the top of the back cover 2.

[0054] During installation, first install the circuit board 4 and insulating board 5 on the outside of the central shaft 3. Then, slowly insert the rear cover 2 into the bottom part of the outer casing 1, while simultaneously inserting a portion of the mounting protrusion 22 into the mounting notch 41. Then, rotate the rear cover 2. Under the action of the mounting protrusion 22, the rear cover 2 drives the circuit board 4 and the Hall element patch 43 to rotate. At the same time, observe the oscilloscope. Stop rotating when the three-phase back voltage is aligned with the Hall reference point. At this point, apply glue between the bottom of the rear cover 2 and the outer casing 1, and fully insert the top of the rear cover 2 into the outer casing 1 to achieve a stable connection between the rear cover 2 and the outer casing 1.

[0055] The structure between the back cover 2 and the circuit board 4 enables the positioning and adjustment of the circuit board 4, which facilitates the assembly of the motor.

[0056] In addition, the back cover 2 is provided with a wire hole 23 to avoid the connection lines between the circuit board 4 and the outside. At the same time, the top of the back cover 2 is provided with a rounded corner structure 24. An annular gap 26 is formed between the rounded corner structure 24 and the bottom of the mounting protrusion 22 with an angular structure. When the back cover 2 and the outer shell 1 are bonded together with glue, the glue will enter into the annular gap 26, increasing the amount of glue stored and the contact area, thereby improving the stability of the connection structure between the back cover 2 and the outer shell 1.

[0057] The preferred embodiments of the present invention have been described in detail above, but it should be understood that, if necessary, aspects of the embodiments can be modified to utilize aspects, features, and concepts from various patents, applications, and publications to provide other embodiments.

[0058] In light of the detailed description above, these and other changes can be made to the embodiments. Generally, the terminology used in the claims should not be considered limited to the specific embodiments disclosed in the specification and claims, but should be understood to include all possible embodiments together with the full scope of equivalents enjoyed by these claims.

[0059] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A brushless electric motor characterized by, The brushless motor includes: The outer casing is cylindrical about an axis and has coils installed on its inner wall; The rear cover is connected to the bottom end of the outer shell and has a mounting protrusion on its top surface; A central shaft, located inside the housing and externally fitted with a magnet, the top end of the central shaft being rotatably connected to the housing and the bottom end being rotatably connected to the rear cover; and The circuit board has a mounting notch that fits onto the mounting protrusion, and the circuit board has a Hall element patch that is located below the magnet and cooperates with the magnet to detect the rotation of the central shaft.

2. The brushless motor of claim 1, wherein, The brushless motor also includes an insulating plate, which is located between the rear cover and the circuit board and has a clearance notch to avoid the mounting protrusion.

3. The brushless motor of claim 1, wherein, The mounting protrusion is located at the edge of the rear cover; The mounting notch opens radially outward toward the circuit board.

4. The brushless motor of claim 1, wherein, The two mounting protrusions are symmetrical with respect to the axis. The circuit board has two mounting notches that respectively engage with the two mounting protrusions.

5. The brushless motor of claim 1, wherein, The rear cover is also provided with a protruding annular step on its radial outer side; The bottom end of the outer shell abuts against the top end of the annular step and is connected to the annular step.

6. The brushless motor of claim 1, wherein, The top end of the central shaft is rotatably connected to the outer casing via a bearing, and the bottom end is rotatably connected to the rear cover via another bearing.

7. The brushless motor of claim 1, wherein, The brushless motor also includes two counterweights, which are located inside the housing and are respectively connected to the bottom and top of the central shaft.

8. The brushless motor of claim 1, wherein, The brushless motor also includes: An inner magnetic yoke, wherein the inner magnetic yoke is looped around the radially outer side of the central axis and located radially inside the magnet; An outer magnetic yoke is connected to the inner wall of the outer casing and is located radially outside the coil.

9. The brushless motor according to claim 8, characterized in that, The inner magnetic yoke comprises multiple layers of silicon steel sheets stacked along the axial direction of the central axis.

10. The brushless motor of claim 8, wherein, The outer magnetic yoke comprises multiple layers of silicon steel sheets stacked along the axial direction of the central axis.

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