Built-in motorized spindle permanent magnet synchronous motor structure for horizontal machining center

Abstract

The invention provides a built-in motorized spindle permanent magnet synchronous motor structure for a horizontal machining center. The built-in motorized spindle permanent magnet synchronous motor structure comprises a stator water-cooled jacket, a stator iron core, a rotor iron core, a permanent magnet and a motorized spindle rotating shaft. The motorized spindle motor is actually a shell-free motor, a motorized spindle rotating shaft and a machine tool spindle are combined into a whole, and a motorized spindle shell and a stator water-cooled jacket are combined into a whole. According to the motorized spindle motor structure disclosed by the invention, virtual teeth with unequal widths are additionally arranged on the tooth crests of the stator iron core, and the tooth crests are chamfered with unequal angles; a rotor core adopts non-uniform segmented herringbone skewed poles, magnetic steel included angles are arranged in an equal difference mode, and pole staggering is achieved through installation of auxiliary round holes. The permanent magnet adopts non-uniform blocks with unequal widths and unequal thicknesses; and the magnetic isolation bridge adopts a differentiated shape. The invention has the advantages of compact structure, short transmission chain length, smaller harmonic content, electromagnetic vibration suppression and the like.

Description

Technical Field

[0001] The invention relates to the field of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center, and in particular to a built-in electric spindle permanent magnet synchronous motor structure for a horizontal machining center. Background Art

[0002] The electric spindle motor is the power source of the electric spindle, and its product design performance has a decisive influence on the machining accuracy, machining efficiency and reliability of the parts. In order to ensure the best cutting conditions under any circumstances, the electric spindle is required to maintain high precision regardless of whether it is running at high or low speed. However, the vibration or torque pulsation of the electric spindle will leave machining marks on the surface of the parts. Excessive harmonic content of the motor will produce large losses, aggravate the heat dissipation problem of the high-speed electric spindle motor, and cause heating and deformation of the output shaft end. How to suppress the electric spindle cogging torque, torque pulsation, and harmonics from the perspective of the design of the electric spindle motor body is an urgent problem to be solved. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a built-in electric spindle permanent magnet synchronous motor structure for a horizontal machining center, which can weaken the motor torque pulsation and cogging torque, has a smaller harmonic content, and can suppress electromagnetic vibration. The design of unequal width virtual tooth stator core, non-uniform segmented herringbone skewed pole rotor core, unequal width and thickness non-uniform block permanent magnets, and differentiated magnetic isolation bridge shapes, using complementary structures to offset most of the cogging torque fundamental wave, the total amplitude of spatial harmonics is significantly reduced.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme:

[0005] A built-in electric spindle permanent magnet synchronous motor structure for a horizontal machining center comprises a stator water cooling jacket, an unequal width virtual tooth stator core, a non-uniform segmented herringbone skewed pole rotor core, unequal width, unequal thickness, non-uniform block permanent magnets, and an electric spindle shaft; the unequal width, unequal thickness, non-uniform block permanent magnets are inserted into the non-uniform segmented herringbone skewed pole rotor core, the non-uniform segmented herringbone skewed pole rotor core is sleeved on the electric spindle shaft, the unequal width virtual tooth stator core is pressed into the stator water cooling jacket, the non-uniform segmented herringbone skewed pole rotor core, the unequal width, unequal thickness, non-uniform block permanent magnets, and the electric spindle shaft are integrally installed in the stator water cooling jacket and the unequal width virtual tooth stator core as a whole in the electric spindle housing; the unequal width, unequal thickness, non-uniform block permanent magnets and the electric spindle shaft are integrally installed in the stator water cooling jacket and the unequal width virtual tooth stator core as a whole. The uniformly divided block permanent magnets include multiple groups of N-pole permanent magnets and S-pole permanent magnets, the widths and heights of the multiple groups of N-pole permanent magnets and S-pole permanent magnets are different, and the surfaces of the non-uniformly divided block permanent magnets of unequal width and thickness are coated with adhesive and then inserted into the slots of the stator core of unequal width virtual teeth; the non-uniformly divided segmented herringbone skewed pole rotor core is heat-fitted onto the electric spindle shaft in an interference fit manner, the electric spindle housing and the stator water cooling jacket are integrated, and the stator core of unequal width virtual teeth is heat-pressed into the stator water cooling jacket in an interference fit manner; the stator core of unequal width virtual teeth, the non-uniformly divided segmented herringbone skewed pole rotor core, the non-uniformly divided block permanent magnets of unequal width and thickness, and the differentiated magnetic isolation bridge shapes are complementarily combined to offset the fundamental wave of the tooth slot torque and reduce the total amplitude of the spatial harmonics.

[0006] Furthermore, a semi-elliptical auxiliary slot is opened on the top of the stator teeth of the unequal width virtual tooth stator core, and a π / 4 chamfer is set at one quarter of the two sides of the tooth.

[0007] Furthermore, rectangular auxiliary slots are opened at the tops of adjacent stator teeth, and π / 6 chamfers are set at two-fifths of the sides of the teeth.

[0008] Furthermore, the semi-elliptical auxiliary grooves and the rectangular auxiliary grooves are staggered and evenly distributed in the circumferential direction.

[0009] Furthermore, the non-uniform segmented herringbone skewed pole rotor core is divided into six non-uniform segments in the axial direction, wherein L1=L6>L2=L5>L3=L4, and L1+L3=2L2 satisfies an arithmetic progression relationship, and the six segments of magnetic poles are arranged axially in a herringbone shape; L1-L6 are the axial lengths of each segment of the non-uniform segmented herringbone skewed pole rotor core.

[0010] Furthermore, the angle between two sets of permanent magnets with the same polarity θ1+ θ3=2θ2 satisfies the arithmetic progression relationship, θ 1、 θ 2、 θ3 is the angle formed between the extended lines of the lower edges of two groups of permanent magnets of unequal width and thickness with the same polarity.

[0011] Furthermore, the distance R1+R3=2R2 from the intersection of the lower edges of the two groups of magnets with the same polarity to the center line of the rotating shaft satisfies an arithmetic progression relationship; R1, R2, and R3 are respectively the distances from the intersection of the extended lines of the lower edges of the two groups of permanent magnets with the same polarity to the center line of the rotating shaft.

[0012] Furthermore, the rotor core segment with a length of L1 has an auxiliary circular hole on the center line of the angle of π / 4-α, the rotor core segment with a length of L2 has an auxiliary circular hole on the center line of the angle of π / 4, and the rotor core segment with a length of L3 has an auxiliary circular hole on the center line of the angle of π / 4+α.

[0013] Furthermore, the non-uniform segmented permanent magnets of unequal width and thickness include three segments of permanent magnets, the widths of the three segments of permanent magnets are b1, b2, and b3, and the thicknesses are h1, h2, and h3, respectively; wherein, b1+b2=2b3 satisfies an arithmetic progression relationship, the thickness h1=h3=0.8h2, and the poles of the non-uniform segmented herringbone skew-pole rotor core corresponding to the permanent magnet at a thickness of h1 are arranged with isosceles triangle chamfers.

[0014] Furthermore, the permanent magnets with a thickness of h3 corresponding to the L1 segment of the rotor core are provided with rounded corners at the magnetic isolation bridges, the permanent magnets with a thickness of h3 corresponding to the L2 segment of the rotor core are provided with overhanging triangles at the magnetic isolation bridges, and the permanent magnets with a thickness of h3 corresponding to the L3 segment of the rotor core are provided with inner chamfers at the magnetic isolation bridges.

[0015] The beneficial effects of the present invention compared with the prior art are:

[0016] 1. The unequal width virtual tooth stator core designed by the present invention not only adopts non-traditional unequal width virtual teeth, but also adopts unequal angle chamfering for the tooth tops of different virtual teeth. This structure can reduce the lever effect of the stator teeth and minimize the possibility of converting the tangential torque fluctuation into the radial vibration of the stator yoke. These virtual slots that are not embedded in the windings expand the lowest common multiple of the number of poles and the number of slots, so that the magnetic circuit is more optimized.

[0017] 2. The traditional rotor core segmented skewed poles are axially uniformly segmented and have the same magnet angle, ignoring the existence of the pole edge effect, which will cause the amplitude and phase of each section of the motor tooth torque to deviate from the ideal state, so that after the phase vectors are superimposed, the fundamental and harmonic components cannot be completely offset. The present invention adopts an axially non-uniform six-segment design, changing the axial length and skew angle of each section of the rotor core pole to compensate for the changes in each section of the tooth torque and phase caused by the segmented pole edge effect as much as possible, so that the radial electromagnetic force of the motor is phase-shifted along the axial direction, and the average radial electromagnetic force wave is reduced, thereby weakening the torque pulsation and tooth torque of the motor.

[0018] 3. The present invention adopts a non-traditional permanent magnet structure of unequal width, unequal thickness and non-uniform block structure and isosceles triangle chamfering, and optimizes the air gap flux density by changing the profile of the permanent magnet, which can make the sinusoid higher and the harmonic content smaller.

[0019] 4. The present invention adopts a non-traditional differentiated magnetic isolation bridge shape with unequal width, unequal thickness and non-uniform block permanent magnets to optimize the air gap magnetic field distribution, eliminate specific order high-order harmonics, and effectively reduce the cogging torque while also improving the weak magnetic field speed expansion capability.

[0020] 5. The four structures adopted in the present invention cooperate with each other and are indispensable. Such complementary structures can offset most of the fundamental waves of the cogging torque, and the total amplitude of the spatial harmonics is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center of the present invention;

[0022] Figure 2 This is a schematic diagram of virtual teeth of unequal width in the stator core;

[0023] Figure 3 It is a schematic diagram of the non-uniform segmented herringbone skewed poles of the rotor core;

[0024] Figure 4 This is a comparison diagram of three different rotor core structures;

[0025] Figure 5 This is a diagram of the non-uniform division of permanent magnets with unequal widths and thicknesses.

[0026] Among them, the accompanying drawings are marked as: stator water cooling jacket 1, unequal width virtual tooth stator core 2, non-uniform segmented herringbone skew pole rotor core 3, unequal width, unequal thickness and non-uniform block permanent magnets 4, electric spindle shaft 5, stator tooth top 6, adjacent stator tooth top 7, semi-elliptical auxiliary groove 8, rectangular auxiliary groove 9, chamfered corner 10, overhanging triangle 11, inner chamfer 12, isosceles triangle chamfer 13. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other. The present invention is described in detail below in conjunction with the accompanying drawings.

[0028] The present invention designs a stator core 2 with virtual teeth of unequal width, a non-uniform segmented herringbone skew-pole rotor core 3, non-uniform block permanent magnets of unequal width and thickness 4, and a differentiated magnetic isolation bridge shape, and utilizes a complementary structure to offset most of the fundamental wave of the tooth slot torque, thereby significantly reducing the total amplitude of the spatial harmonics.

[0029] like Figure 1 As shown, the structure of the built-in electric spindle permanent magnet synchronous motor for a horizontal machining center of the present invention includes a stator water cooling jacket 1, an unequal width virtual tooth stator core 2, a non-uniform segmented herringbone skewed pole rotor core 3, unequal width, unequal thickness and non-uniform block permanent magnets 4, and an electric spindle shaft 5.

[0030] The structure of the built-in electric spindle permanent magnet synchronous motor for the horizontal machining center is a housing-free motor, and its installation sequence is: first, insert the non-uniform segmented permanent magnets 4 of unequal width and thickness into the non-uniform segmented herringbone skewed pole rotor core 3, then sleeve the non-uniform segmented herringbone skewed pole rotor core 3 on the electric spindle shaft 5, and then press the unequal width virtual tooth stator core 2 into the stator water cooling jacket 1, and finally install the non-uniform segmented herringbone skewed pole rotor core 3, the unequal width and thickness non-uniform segmented permanent magnets 4, and the electric spindle shaft 5 as a whole into the electric spindle housing which is integrated with the stator water cooling jacket 1 and the unequal width virtual tooth stator core 2.

[0031] The non-uniform block permanent magnets 4 of unequal width and thickness include multiple groups of N-pole permanent magnets and S-pole permanent magnets, and the widths and heights of the multiple groups of N-pole permanent magnets and S-pole permanent magnets are different. Preferably, there are 8 groups, with four groups of N-pole permanent magnets and four groups of S-pole permanent magnets; two groups of N-pole permanent magnets are arranged adjacent to each other, and are symmetrically arranged with respect to the electric spindle shaft 5 with respect to the other two adjacent groups of N-pole permanent magnets; two groups of S-pole permanent magnets are arranged adjacent to each other, and are symmetrically arranged with respect to the electric spindle shaft 5 with respect to the other two adjacent groups of S-pole permanent magnets.

[0032] After the surfaces of the non-uniform segmented permanent magnets 4 with unequal width and thickness are coated with adhesive, they are respectively inserted into the slots corresponding to the 6 sections of the rotor core with lengths L1-L6, and the rotor cores with lengths L1-L6 are installed through auxiliary circular holes to form a non-uniform segmented herringbone skewed pole rotor core 3; the non-uniform segmented herringbone skewed pole rotor core 3 is heat-fitted on the electric spindle shaft 5 in an interference fit manner, the electric spindle housing and the stator water cooling jacket 1 are integrated, and the unequal width virtual tooth stator core 2 is heat-pressed in the stator water cooling jacket 1 in an interference fit manner; the non-uniform segmented herringbone skewed pole rotor core 3, the non-uniform segmented permanent magnets 4 with unequal width and thickness, and the electric spindle shaft 5 are integrally installed in the electric spindle housing, and it is ensured that the electric spindle shaft 5 is located at the center of the stator water cooling jacket 1.

[0033] like Figure 2As shown, a semi-elliptical auxiliary slot 8 is formed on the stator tooth top 6, and a π / 4 chamfer is performed at one-fourth of the tooth sides; a rectangular auxiliary slot 9 is formed on the adjacent stator tooth top 7, and a π / 6 chamfer is performed at two-fifths of the tooth sides. The semi-elliptical auxiliary slots 8 and the rectangular auxiliary slots 9 are evenly distributed in an alternating manner in the circumferential direction.

[0034] Figure 3 As shown, the non-uniform segmented herringbone skewed pole rotor core 3 is divided into six non-uniform segments in the axial direction, where L1=L6>L2=L5>L3=L4, and L1+L3=2L2 satisfies an arithmetic progression relationship, and the six segments of magnetic poles are arranged in a herringbone shape in the axial direction. Among them, L1-L6 refers to the axial length of each segment of the non-uniform segmented herringbone skewed pole rotor core 3, and also refers to the number of each segment.

[0035] like Figure 4 As shown, the angle θ1+ θ3=2θ2 between the two groups of permanent magnets with the same polarity satisfies an arithmetic progression relationship, wherein θ1, θ2, and θ3 are respectively the angles formed between the extension lines of the lower edges of the two groups of permanent magnets with the same polarity; the distance R1+R3=2R2 from the intersection of the extension lines of the lower edges of the two groups of permanent magnets with the same polarity to the center line of the shaft satisfies an arithmetic progression relationship, wherein R1, R2, and R3 are respectively the distances from the intersection of the extension lines of the lower edges of the two groups of permanent magnets with the same polarity to the center line of the shaft; the L1 section rotor core opens an auxiliary circular hole on the center line of the π / 4-α angle ( Figure 4 In the left picture ), the L2 section rotor core opens an auxiliary circular hole on the center line of the π / 4 angle ( Figure 4 In the middle picture ), the L3 section rotor core opens an auxiliary circular hole on the center line of the π / 4+α angle ( Figure 4 In the right picture ), 6 sections of rotor core L1-L6 are installed through auxiliary circular holes Figure 3 Non-uniform segmented herringbone skewed pole rotor core. Figure 4 In the figure, R0 represents the distance from the center of the auxiliary hole to the center line of the shaft.

[0036] like Figure 5 As shown, the non-uniform block permanent magnet 4 of unequal width and thickness includes three sections of permanent magnets, and the widths of the three sections of permanent magnets are b1, b2, and b3, respectively, and the thicknesses are h1, h2, and h3, respectively. b1, b2, and b3 are not equal, and h1, h2, and h3 are not equal. The width b1+b2=2b3 satisfies the arithmetic progression relationship, the thickness h1=h3=0.8h2, and the permanent magnet with a thickness of h1 has an isosceles triangle chamfer 13. The permanent magnet has an unequal width, unequal thickness, non-uniform block structure and an isosceles triangle chamfer. By changing the profile of the permanent magnet to achieve the purpose of optimizing the air gap magnetic flux density, the sinusoidal degree can be higher and the harmonic content can be smaller.

[0037] In order to match the non-uniform block permanent magnet structure with unequal width and thickness, the magnetic isolation bridge is provided with a rounded corner 10 at the permanent magnet with a thickness of h3 corresponding to the L1 segment rotor core, the magnetic isolation bridge is provided with an outward triangle 11 at the permanent magnet with a thickness of h3 corresponding to the L2 segment rotor core, and the magnetic isolation bridge is provided with an inner chamfer 12 at the permanent magnet with a thickness of h3 corresponding to the L3 segment rotor core. The differentiated magnetic isolation bridge shape matched with the non-uniform block permanent magnet with unequal width and thickness can optimize the air gap magnetic field distribution, eliminate high-order harmonics of a specific order, and effectively reduce the cogging torque while also improving the weak magnetic speed expansion capability.

Claims

1. A built-in electric spindle permanent magnet synchronous motor structure for a horizontal machining center, characterized in that: It comprises a stator water cooling jacket, an unequal width virtual tooth stator core, a non-uniform segmented herringbone skewed pole rotor core, unequal width, unequal thickness, non-uniform block permanent magnets, and an electric spindle shaft; the unequal width, unequal thickness, non-uniform block permanent magnets are inserted into the non-uniform segmented herringbone skewed pole rotor core, the non-uniform segmented herringbone skewed pole rotor core is sleeved on the electric spindle shaft, the unequal width virtual tooth stator core is pressed into the stator water cooling jacket, and the non-uniform segmented herringbone skewed pole rotor core, the unequal width, unequal thickness, non-uniform block permanent magnets, and the electric spindle shaft are integrally installed in the stator water cooling jacket and the unequal width virtual tooth stator core as a whole in the electric spindle housing; The non-uniform block permanent magnets with unequal width and thickness include multiple groups of N-pole permanent magnets and S-pole permanent magnets, and the widths and heights of the multiple groups of N-pole permanent magnets and S-pole permanent magnets are different. The surfaces of the non-uniform block permanent magnets with unequal width and thickness are coated with adhesive and then inserted into the slots of the stator core with unequal width virtual teeth. The non-uniform segmented herringbone skewed pole rotor core is heat-fitted on the electric spindle shaft in an interference fit manner, the electric spindle housing is integrated with the stator water cooling jacket, and the stator core with unequal width virtual teeth is heat-pressed in the stator water cooling jacket in an interference fit manner. The unequal width virtual tooth stator core, the non-uniform segmented herringbone skew pole rotor core, the unequal width and thickness non-uniform block permanent magnets, and the differentiated magnetic isolation bridge shapes are complementary to offset the fundamental wave of the tooth slot torque and reduce the total amplitude of the spatial harmonics.

2. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 1, characterized in that: The stator teeth of the unequal width virtual tooth stator core are provided with semi-elliptical auxiliary slots on the tops, and a π / 4 chamfer is provided at one quarter of the sides of the teeth.

3. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 2, characterized in that: Rectangular auxiliary slots are opened on the tops of adjacent stator teeth, and π / 6 chamfers are set at two-fifths of the sides of the teeth.

4. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 3, characterized in that: The semi-elliptical auxiliary grooves and the rectangular auxiliary grooves are staggered and evenly distributed in the circumferential direction.

5. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 1, characterized in that: The non-uniform segmented herringbone skewed pole rotor core is divided into six non-uniform segments in the axial direction, among which L1=L6>L2=L5>L3=L4, and L1+L3=2L2 satisfies the arithmetic progression relationship, and the six segments of magnetic poles are arranged in a herringbone shape in the axial direction; L1-L6 is the axial length of each segment of the non-uniform segmented herringbone skewed pole rotor core.

6. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 5, characterized in that: The angle between two sets of permanent magnets with the same polarity θ1+ θ3=2θ2 satisfies the arithmetic progression relationship, θ 1、 θ 2、 θ3 is the angle formed between the extended lines of the lower edges of two groups of permanent magnets of unequal width and thickness with the same polarity.

7. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 5, characterized in that: The distance R1+R3=2R2 from the intersection of the lower edges of the two sets of magnets with the same polarity to the center line of the rotating shaft satisfies an arithmetic progression relationship; R1, R2, and R3 are respectively the distances from the intersection of the extended lines of the lower edges of the two sets of permanent magnets with the same polarity to the center line of the rotating shaft.

8. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 5, characterized in that: The rotor core segment with a length of L1 has an auxiliary circular hole on the center line of the angle of π / 4-α, the rotor core segment with a length of L2 has an auxiliary circular hole on the center line of the angle of π / 4, and the rotor core segment with a length of L3 has an auxiliary circular hole on the center line of the angle of π / 4+α.

9. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 4, characterized in that: The non-uniform segmented permanent magnets with unequal width and thickness include three segments of permanent magnets, the widths of the three segments of permanent magnets are b1, b2, and b3, and the thicknesses are h1, h2, and h3, respectively; wherein, b1+b2=2b3 satisfies an arithmetic progression relationship, the thickness h1=h3=0.8h2, and the magnetic poles of the non-uniform segmented herringbone skew-pole rotor core corresponding to the permanent magnet at the thickness h1 are arranged with isosceles triangle chamfers.

10. The structure of a built-in electric spindle permanent magnet synchronous motor for a horizontal machining center according to claim 8, characterized in that: The permanent magnets with a thickness of h3 corresponding to the L1 segment of the rotor core are provided with rounded corners at the magnetic isolation bridges, the permanent magnets with a thickness of h3 corresponding to the L2 segment of the rotor core are provided with overhanging triangles at the magnetic isolation bridges, and the permanent magnets with a thickness of h3 corresponding to the L3 segment of the rotor core are provided with inner chamfers at the magnetic isolation bridges.

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