Permanent magnet brushless direct current spindle motor

Abstract

The utility model provides a permanent magnet brushless direct current spindle motor, and relates to the technical field of spindle motors, and a shaft body comprises a first shaft section, a second shaft section and a third shaft section of which the diameters are sequentially increased. And the first shaft section and the second shaft section are transited through a conical surface. A cutter mounting hole is formed in the third shaft section in the axis direction. The stator mounting seat is provided with a through hole used for sleeving the outer side of the shaft body. One end of the stator mounting seat is a mounting end and is mounted on the first shaft section through a first bearing, and the stator part is fixedly mounted on the outer circumference of the mounting end. The end part of the first shaft section is fixedly connected with the rear end cover, the rear end cover is connected with the outer rotor, and the outer rotor sleeves the outer side of the stator part. And one end of the stator mounting seat is a fixed end, and the fixed end is mounted on the second shaft section through a second bearing and is connected with the bearing end cover to fix the second bearing. The shaft body is of a three-section design, and the second shaft section and the first shaft section are in conical surface transition, so that the rigidity of the motor and the shaft body can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of spindle motors, in particular to a permanent magnet brushless DC spindle motor. Background Art

[0002] Permanent magnet brushless motors have the advantages of high efficiency, long life and low noise, so they are widely used in various fields. Existing permanent magnet brushless motors are generally connected to the tool through a mechanical spindle on the machine tool. The mechanical spindle is large and has low precision, making it difficult to use in CNC machine tools. In addition, the existing permanent magnet brushless motors not only do not have mounting holes for fixing the tool on the rotating shaft, but also have insufficient rigidity, making it difficult to directly use them as spindle motors. Utility Model Content

[0003] To solve the above technical problems, this embodiment provides a permanent magnet brushless DC spindle motor, which not only has a mounting hole for fixing a tool on the rotating shaft, but also improves the rigidity of the motor to meet the conditions for directly using it as a spindle motor.

[0004] The technical solution adopted by the utility model is:

[0005] A permanent magnet brushless DC spindle motor comprises: a shaft body, a stator mounting seat, a stator part, an outer rotor, a rear end cover, a first bearing, a second bearing, and a bearing end cover.

[0006] The shaft body comprises a first shaft section, a second shaft section and a third shaft section with successively increasing diameters; a conical surface transition is provided between the first shaft section and the second shaft section; and a tool mounting hole is provided in the third shaft section along the axial direction.

[0007] The stator mounting seat has a through hole arranged along the axis, which is used to be sleeved on the outside of the shaft body; one end of the stator mounting seat is the mounting end, which is mounted on the first shaft section through the first bearing, and the stator part is fixedly mounted on the outer circumference of the mounting end; the end of the first shaft section is fixedly connected to the rear end cover, the rear end cover is connected to the outer rotor, and the outer rotor is sleeved on the outside of the stator part.

[0008] One end of the stator mounting seat is a fixed end, which is mounted on the second shaft section through a second bearing and connected to a bearing end cover to fix the second bearing.

[0009] The beneficial effects of the utility model are:

[0010] The shaft body in the utility model has three shaft sections with increasing diameters in sequence. The diameter of the first shaft section is the smallest and can pass through the stator mounting seat, thereby reducing the overall size of the permanent magnet brushless DC spindle motor. The diameter of the third shaft section is the largest, which is convenient for setting the tool mounting hole, and the rigidity of the shaft body can be increased by increasing the diameter. The second shaft section and the first shaft section are transitioned through a conical surface. Compared with the existing stepped shaft, it can not only further improve the rigidity of the shaft body, but also improve the stress condition of the shaft body, so that the permanent magnet brushless DC spindle motor provided by the utility model can be directly used as a spindle motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a structural schematic diagram of a permanent magnet brushless DC spindle motor in an embodiment of the utility model;

[0012] Figure 2 It is a cross-sectional schematic diagram of a permanent magnet brushless DC spindle motor in an embodiment of the utility model;

[0013] Figure 3 This is a structural schematic diagram of a stator mounting seat in an embodiment of the utility model;

[0014] Figure 4 It is a cross-sectional schematic diagram of a stator mounting seat in an embodiment of the utility model;

[0015] Figure 5 This is a schematic diagram of the structure of the bearing end cover in the embodiment of the utility model;

[0016] Figure 6 For this utility model Figure 5 Schematic diagram of the cross section of the AA section;

[0017] Figure 7 This is a schematic diagram of the connection between the outer rotor and the rear end cover in the embodiment of the utility model;

[0018] Figure 8 It is a schematic structural diagram of the rear end cover in an embodiment of the utility model.

[0019] Among them, 1: shaft body; 2: stator mounting seat; 3: stator part; 4: outer rotor; 5: rear end cover; 6: first bearing; 7: second bearing; 8: bearing end cover; 9: spring washer; 10: copper gasket; 11: first shaft section; 12: second shaft section; 13: third shaft section; 14: tool mounting hole; 15: threaded hole; 16: vent hole; 21: through hole; 22: mounting end; 23: fixed end; 211: first section through hole; 212: second section through hole; 213: third section through hole; 41: rotor housing; 42: permanent magnet; 51: concave-convex structure; 81: metal fixing seat; 82: plastic protective shell; 83: first mounting hole; 84: second mounting hole; 85: cylindrical housing. DETAILED DESCRIPTION

[0020] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. The connection can be a direct connection or an indirect connection.

[0023] In addition, in the present utility model, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0024] See also Figure 1 and Figure 2 , Figure 1 A schematic diagram of the structure of a permanent magnet brushless DC spindle motor provided by an embodiment of the utility model, Figure 2 It is a cross-sectional schematic diagram of a permanent magnet brushless DC spindle motor, which includes: a shaft body 1, a stator mounting seat 2, a stator part 3, an outer rotor 4, a rear end cover 5, a first bearing 6, a second bearing 7, and a bearing end cover 8.

[0025] The split design of the rear end cover 5 and the outer rotor 4 can make the manufacture and installation of the rotor simple and quick, thereby reducing costs.

[0026] The shaft body 1 comprises a first shaft section 11, a second shaft section 12 and a third shaft section 13 with diameters increasing successively; the first shaft section 11 and the second shaft section 12 are transitioned by a conical surface; the third shaft section 13 is provided with a tool mounting hole 14 along the axial direction.

[0027] Among them, in order to be able to install the tool, the shaft body 1 needs to be provided with a tool installation hole 14 in the axial direction. In order to ensure that the shaft body 1 has greater strength, the diameter of the shaft body 1 in the third shaft section 13 needs to be increased. However, the first shaft section 11 needs to pass through the stator mounting seat 2 to connect with the rear end cover 5. If the diameter is too large, the volume of the permanent magnet brushless DC spindle motor will be too large. Therefore, it is necessary to determine the diameter of the first shaft section 11 according to the volume of the permanent magnet brushless DC spindle motor, and set the diameter of the first shaft section 11 to be smaller. The second shaft section 12 is used to connect the first shaft section 11 and the second shaft section 12, and to install the second bearing 7, and its diameter size is between the first shaft section 11 and the second shaft section 12. The first shaft section 11 and the second shaft section 12 are transitioned by a conical surface, and the size of the conical surface can be determined according to the stator mounting seat 2, so that the shaft body 1 and the stator mounting seat 2 will not contact each other. The conical surface used for transition can be one or multiple conical surfaces with different tapers. Multiple conical surfaces are connected and transitioned, which can facilitate design and improve the rigidity of the shaft body 1 as much as possible. Symmetrical flat portions may be provided on the first shaft section 11 to facilitate fixation with the rear end cover 5 .

[0028] The stator mounting seat 2 has a through hole 21 arranged along the axis, which is used to be sleeved on the outside of the shaft body 1; one end of the stator mounting seat 2 is a mounting end 22; the mounting end 22 is mounted on the first shaft section 11 through the first bearing 6, and the stator part 3 is fixedly mounted on the outer circumference of the mounting end 22; the end of the first shaft section 11 is fixedly connected to the rear end cover 5, the rear end cover 5 is connected to the outer rotor 4, and the outer rotor 4 is sleeved on the outside of the stator part 3.

[0029] The stator mounting seat 2 has a through hole 21 arranged along the axis, and the shaft body 1 passes through the through hole 21, so that the end of the third shaft section 13 can be connected to the rear end cover 5. The mounting end 22 of the stator part 3 is cylindrical, the inner side is used to accommodate the shaft body 1, and the outer side is used to install the stator part 3.

[0030] One end of the stator mounting seat 2 is a fixed end 23 , which is mounted on the second shaft section 12 through the second bearing 7 and connected to the bearing end cover 8 to fix the second bearing 7 .

[0031] Among them, the diameter of the through hole 21 of the stator mounting seat 2 at the fixed end 23 can be designed to be larger so as to cooperate with the second shaft section 12. And a wire outlet hole can also be set on the outside of the fixed end 23 for leading out the stator wire harness of the stator part 3. The inner ring of the second bearing 7 is interference fit with the second shaft section 12, and the outer ring of the second bearing 7 is interference fit with the fixed end 23 of the stator mounting seat 2, which reduces the gap between the shaft body 1 and the stator mounting seat 2 and can improve the overall stiffness of the motor. The second bearings 7 can be arranged in pairs, and the second bearings 7 are preferably fitted with interference fit so that the bearings receive axial force, thereby eliminating the gap in the inner ring of the bearing and increasing the rigidity of the bearing, reducing the gap of the permanent magnet brushless DC motor, and improving the overall rigidity of the motor.

[0032] In this embodiment, the shaft body 1 has three shaft sections with increasing diameters in sequence. The diameter of the first shaft section 11 is the smallest and can pass through the stator mounting seat 2, thereby reducing the overall size of the permanent magnet brushless DC spindle motor. The diameter of the third shaft section 13 is the largest, which is convenient for setting the tool mounting hole 14, and the rigidity of the shaft body 1 can be increased by increasing the diameter. The second shaft section 12 and the first shaft section 11 are transitioned through a conical surface. Compared with the existing stepped shaft, it can not only further improve the rigidity of the shaft body 1, but also improve the stress condition of the shaft body 1, so that the permanent magnet brushless DC spindle motor provided in this embodiment can be directly used as a spindle motor.

[0033] like Figure 3 and Figure 4 As shown, Figure 3 This is a schematic diagram of the structure of the stator mounting seat. Figure 4 2 is a cross-sectional schematic diagram of the stator mounting seat. In this embodiment, the through hole 21 forms two stepped holes with different apertures at the mounting end 22 and the fixing end 23, and the two stepped holes are transitioned by a conical surface.

[0034] Among them, the inner diameters of the through hole 21 of the stator mounting seat 2 at the mounting end 22 and the fixed end 23 are different, so that the stepped through hole 21 can be formed with the shaft body 1. The stepped through hole 21 can include three sections. The first section through hole 211 is used to install the first bearing 6, the second section through hole 212 is used to maintain a gap with the shaft body 1, and the third section through hole 213 is used to install the second bearing 7. The transition between the second section and the third section is made through a conical surface, which can not only improve the strength of the stator mounting seat 2, but also provide a larger installation space for the transition area between the first shaft section 11 and the second shaft section 12 of the shaft body 1. There is enough space to adjust the size of the conical surface between the first shaft section 11 and the second shaft section 12 of the shaft body 1, so that the rigidity of the shaft body 1 can be further improved. The outer sides of the mounting end 22 and the fixed end 23 can be transitioned through a conical surface or an arc surface, so as to improve the strength of the stator mounting seat 2 at the connection between the two ends.

[0035] In this embodiment, the first bearing 6 is a deep groove ball bearing, and the end surface of the inner ring of the first bearing 6 is provided with a spring washer 9 and a copper washer 10 .

[0036] Among them, the deep groove ball bearing is cheap, and using it as the first bearing 6 can reduce the manufacturing cost of the permanent magnet brushless DC spindle motor provided by this embodiment. Preferably, the copper gasket 10 can be arranged between the end face of the inner ring of the first bearing 6 and the rear end cover 5, and the spring gasket 9 can be arranged between the first bearing 6 and the mounting end 22 of the stator mounting seat 2. The spring gasket 9 and the copper gasket 10 can eliminate the gap between the inner ring of the first bearing 6 and the two contact surfaces together, and make the axial force of the first bearing 6 more uniform, further improving the overall stiffness of the permanent magnet brushless DC spindle motor.

[0037] like Figure 5 and Figure 6 As shown, Figure 5 is a schematic diagram of the structure of the bearing end cover. Figure 6 for Figure 5 In the present embodiment, the bearing end cover 8 comprises a metal fixing seat 81 and a plastic protective shell 82; the metal fixing seat 81 is provided with a first mounting hole 83 connected to the stator mounting seat 2, and a second mounting hole 84 for mounting the permanent magnet brushless DC spindle motor; the plastic protective shell 82 is wrapped around the outside of the metal fixing seat 81.

[0038] Among them, the bearing end cover 8 can be set to a square shape, and a stepped countersunk hole that docks with the fixed end 23 of the stator mounting seat 2 and the second bearing 7 is set in the middle of the metal fixing seat 81. A mounting hole that cooperates with the first mounting hole 83 is set on the fixed end 23 of the stator mounting seat 2, and the first mounting hole 83 and the second mounting hole 84 can be staggered for easy installation. The second mounting hole 84 is preferably set at the four corners of the metal fixing seat 81 to improve the installation stability of the permanent magnet brushless DC spindle motor on the machine tool. The metal fixing seat 81 is preferably made of aluminum alloy, and the plastic protective shell 82 is preferably hard plastic. The plastic protective shell 82 can prevent processing debris from entering the second bearing 7 and reduce damage to the metal fixing seat 81.

[0039] according to Figure 1 It can be seen that in this embodiment, a threaded hole 15 and a vent hole 16 connected to the tool mounting hole 14 are opened on the third shaft section 13, and the threaded hole 15 and the vent hole 16 are both perpendicular to the tool mounting hole 14. The threaded hole 15 is used to install the top screw for fixing the tool; the vent hole 16 is connected to the bottom of the tool mounting hole 14.

[0040] The gap between the tool mounting hole 14 and the tool is small, and when the tool is installed, a large air pressure is easily generated at the bottom of the tool mounting hole 14, causing the tool to be subjected to outward pressure, affecting the installation stability of the tool. In this embodiment, the top screw is installed through the threaded hole 15 to fix the tool, and the bottom of the tool mounting hole 14 is connected to the outside through the vent hole 16, thereby improving the installation stability of the tool.

[0041] In this embodiment, the dynamic balancing weight removed from the vent hole 16 corresponds to the dynamic balancing weight removed from the threaded hole 15 , so that the shaft body 1 achieves dynamic balance.

[0042] Among them, the threaded hole 15 provided on the shaft body 1 will affect the dynamic balance of the shaft body 1, causing abnormal vibration of the shaft body 1, which may lead to problems such as machine instability, noise and performance degradation. In this embodiment, the threaded hole 15 and the vent hole 16 are arranged relative to each other, and the shaft body 1 can be dynamically balanced by adjusting the dynamic balance weight of the vent hole 16, thereby improving the motion stability of the shaft body 1. The dynamic balance weight mainly includes the weight removal mass and angle, which can be calculated separately according to the dynamic balance formula.

[0043] In this embodiment, the plastic protective shell 82 extends toward the third shaft segment 13 to form a cylindrical shell 85 , and the cylindrical shell 85 covers the vent hole 16 .

[0044] The vent hole 16 may be blocked by processing debris during use, and the plastic protective shell 82 covers it to protect the vent hole 16. A certain gap needs to be set between the plastic protective shell 82 and the third shaft section 13 to facilitate ventilation and prevent the plastic protective shell 82 from affecting the rotation of the shaft body 1.

[0045] like Figure 7 and Figure 8 As shown, Figure 7 This is a schematic diagram of the connection between the outer rotor and the rear end cover. Figure 8 In this embodiment, the outer rotor 4 includes a rotor housing 41 and a permanent magnet 42 , and the rear end cover 5 has an annular flange, which is used to be clamped in the rotor housing 41 , and the annular flange has a concave-convex structure 51 , which is used to fix the permanent magnet 42 .

[0046] Among them, the split structure of the outer rotor 4 and the rear end cover 5 can not only facilitate the installation of the spring washer 9 and the copper gasket 10 on the shaft body 1, but also improve the ability of the permanent magnet brushless DC motor to resist the bending deformation of the rotor during operation. The concave-convex structure 51 of the rear end cover 5 can form a slot with the rotor housing 41. Compared with the technical solution of directly pasting the permanent magnet 42 on the inner wall of the rotor housing in the prior art, the permanent magnet 42 is fixed in the slot in this embodiment, which can prevent the permanent magnet 42 from being displaced and improve the positioning accuracy of the permanent magnet 42.

[0047] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A permanent magnet brushless DC spindle motor, characterized in that: include: A shaft body (1), a stator mounting seat (2), a stator portion (3), an outer rotor (4), a rear end cover (5), a first bearing (6), a second bearing (7), and a bearing end cover (8); The shaft body (1) comprises a first shaft section (11), a second shaft section (12) and a third shaft section (13) whose diameters increase successively; the first shaft section (11) and the second shaft section (12) are transitioned via a conical surface; the third shaft section (13) is provided with a tool mounting hole (14) along the axial direction; The stator mounting seat (2) has a through hole (21) arranged along the axis and used for being sleeved on the outside of the shaft body (1); one end of the stator mounting seat (2) is a mounting end (22), the mounting end (22) is mounted on the first shaft section (11) via the first bearing (6), and the stator part (3) is fixedly mounted on the outer circumference of the mounting end (22); the end of the first shaft section (11) is fixedly connected to the rear end cover (5), the rear end cover (5) is connected to the outer rotor (4), and the outer rotor (4) is sleeved on the outside of the stator part (3); One end of the stator mounting seat (2) is a fixed end (23), and the fixed end (23) is mounted on the second shaft section (12) via the second bearing (7) and is connected to the bearing end cover (8) to fix the second bearing (7).

2. The permanent magnet brushless DC spindle motor according to claim 1, characterized in that: The through hole (21) forms two sections of stepped holes with different hole diameters at the mounting end (22) and the fixing end (23), and the two sections of the stepped holes are transitioned by a conical surface.

3. The permanent magnet brushless DC spindle motor according to claim 1, characterized in that: The first bearing (6) is a deep groove ball bearing, and the end surface of the inner ring of the first bearing (6) is provided with a spring washer (9) and a copper washer (10).

4. The permanent magnet brushless DC spindle motor according to claim 1, characterized in that: The bearing end cover (8) comprises a metal fixing seat (81) and a plastic protective shell (82); the metal fixing seat (81) is provided with a first mounting hole (83) connected to the stator mounting seat (2), and a second mounting hole (84) for mounting the permanent magnet brushless DC spindle motor; the plastic protective shell (82) is wrapped around the outside of the metal fixing seat (81).

5. The permanent magnet brushless DC spindle motor according to claim 4, characterized in that: A threaded hole (15) and a vent hole (16) which are in communication with the tool mounting hole (14) are provided on the third shaft section (13); the threaded hole (15) and the vent hole (16) are both perpendicular to the tool mounting hole (14); the threaded hole (15) is used to install a top screw for fixing the tool; and the vent hole (16) is in communication with the bottom of the tool mounting hole (14).

6. The permanent magnet brushless DC spindle motor according to claim 5, characterized in that: The dynamic balancing weight removed from the vent hole (16) corresponds to the dynamic balancing weight removed from the threaded hole (15), so that the shaft body (1) achieves dynamic balance.

7. The permanent magnet brushless DC spindle motor according to claim 5 or 6, characterized in that: The plastic protective shell (82) extends a cylindrical shell (85) toward the third shaft section (13), and the cylindrical shell (85) covers the vent hole (16).

8. The permanent magnet brushless DC spindle motor according to claim 1, characterized in that: The outer rotor (4) comprises a rotor housing (41) and a permanent magnet (42), the rear end cover (5) has an annular flange, the annular flange is used to be clamped in the rotor housing (41), and the annular flange has a concave-convex structure (51), and the concave-convex structure (51) is used to fix the permanent magnet (42).

Images