Rotor structure and magnetic field modulation permanent magnet motor

Abstract

The invention belongs to the field of motor technical equipment, and particularly relates to a rotor structure and a magnetic field modulation permanent magnet motor. The rotor structure comprises a rotor iron core, rotor auxiliary teeth and a permanent magnet group arranged in the rotor iron core; the rotor core is located in the stator structure, the multiple permanent magnet groups are arranged at intervals in the circumferential direction of the rotor core, one end of each auxiliary tooth is connected with the side surface of the rotor core, the other end of each auxiliary tooth extends towards the stator structure, a gap is formed between the auxiliary tooth and the stator structure, and the multiple rotor auxiliary teeth are arranged at intervals in the circumferential direction of the rotor core. According to the motor provided by the invention, the torque and the torque density of the magnetic field modulation permanent magnet motor can be improved, and the cogging torque is weakened.

Description

Technical Field

[0001] The present invention belongs to the field of motor technology equipment, and in particular relates to a rotor structure and a magnetic field modulation permanent magnet motor. Background Art

[0002] As we all know, permanent magnet motors, as an electromagnetic energy conversion device, are widely used in industrial production and household appliances, such as electric vehicles, wind power generation, washing machines and hair dryers. In low-speed and high-torque applications such as wind power generation, people hope that permanent magnet motors have high torque density and efficiency to eliminate the shortcomings of intermediate transmission devices such as gearboxes and realize direct drive of loads.

[0003] At present, in order to meet the growing high torque performance requirements of permanent magnet motors in industrial production - high torque, high torque density and low cogging torque, the development and design of different topological structures is still one of the hot topics in the research of magnetic field modulation permanent magnet motors. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a rotor structure to solve the problem of how to increase the torque of a permanent magnet motor.

[0005] To achieve the above purpose, the technical solution adopted in this application is:

[0006] In a first aspect, a rotor structure is provided, which cooperates with a stator structure, and the rotor structure includes: a rotor core, rotor auxiliary teeth, and a permanent magnet group arranged in the rotor core; the rotor core is located in the stator structure, a plurality of permanent magnet groups are arranged, and each permanent magnet group is arranged at intervals around the circumference of the rotor core, one end of the auxiliary tooth is connected to the side surface of the rotor core, and the other end of the auxiliary tooth extends toward the stator structure and has a gap with the stator structure, and a plurality of rotor auxiliary teeth are arranged at intervals around the circumference of the rotor core.

[0007] In some embodiments, the rotor auxiliary teeth are provided between any two adjacent permanent magnet groups.

[0008] In some embodiments, the permanent magnet group is disposed between any two adjacent rotor auxiliary teeth.

[0009] In some embodiments, the number of the rotor auxiliary teeth is twice the number of the permanent magnet groups.

[0010] In some embodiments, the thickness of the rotor core along the radial direction is L1, and the thickness of the rotor auxiliary teeth along the radial direction of the rotor core is L2, and L2 is greater than zero and less than 1 / 3*L1.

[0011] In some embodiments, the cross-sectional shape of the rotor auxiliary teeth is polygonal, semicircular or semi-elliptical.

[0012] In some embodiments, a positioning groove is provided on the side surface of the rotor core, and the permanent magnet group includes two permanent magnets, the two permanent magnets are respectively attached to the two side walls of the positioning groove, there is an angle between the two permanent magnets, and the magnetization directions of the two permanent magnets point inside or outside the angle.

[0013] In some embodiments, the rotor structure further includes a positioning block disposed between the two permanent magnets, and the rotor auxiliary teeth are connected to the positioning block.

[0014] In a second aspect, a magnetic field modulation permanent magnet motor is provided, which includes the rotor structure, and the magnetic field modulation permanent magnet motor also includes the stator structure, the stator structure includes a stator core and a plurality of armature windings arranged on the stator core, each of the armature windings is arranged at intervals along the circumference of the stator core, and the rotor core is located inside the stator core.

[0015] In some embodiments, the stator core is provided with Zs stator slots, each armature winding is arranged in each stator slot according to the number of pole pairs Pw, the number of the rotor auxiliary teeth is Zr, and Pw=|Zs-Zr / 2|.

[0016] The beneficial effects of the present application are as follows: the rotor structure includes a rotor core, rotor auxiliary teeth, and a permanent magnet group arranged in the rotor core. The rotor auxiliary teeth change the flow path of the magnetic field generated by the armature current, significantly enhancing the magnetic field generated by the armature current; the magnetic field of the permanent magnet group is greatly enhanced by the magnetic field concentration effect, thereby improving the torque and torque density of the magnetic field modulation permanent magnet motor. In addition, the introduction of the rotor auxiliary teeth weakens the cogging torque of the magnetic field modulation permanent magnet motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or exemplary technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a structural schematic diagram of a magnetic field modulated permanent magnet motor provided in an embodiment of the present application;

[0019] Figure 2 yes Figure 1 A schematic diagram of the structure of the stator structure of the magnetic field modulation permanent magnet motor;

[0020] Figure 3 yes Figure 1 A schematic diagram of the rotor structure of a magnetic field modulation permanent magnet motor;

[0021] Figure 4 yes Figure 1 Schematic diagram of armature winding connection of magnetic field modulation permanent magnet motor;

[0022] Figure 5 A comparison diagram of the air gap flux density and its harmonic spectrum generated by the armature winding of the magnetic field modulation permanent magnet motor and the magnetic field modulation permanent magnet motor without rotor auxiliary teeth provided in the embodiment of the present application;

[0023] Figure 6 A comparison diagram of the cogging torque of the magnetic field modulation permanent magnet motor and the magnetic field modulation permanent magnet motor without rotor auxiliary teeth provided in the embodiment of the present application;

[0024] Figure 7 This is a comparison chart of the output torque of the magnetic field modulation permanent magnet motor and the magnetic field modulation permanent magnet motor without rotor auxiliary teeth provided in this application.

[0025] Among them, the reference numerals in the figure are:

[0026] 100. Magnetic field modulation permanent magnet motor; 10. Stator structure; 11. Stator core; 12. Armature winding; 20. Rotor structure; 21. Rotor core; 22. Rotor auxiliary teeth; 23. Permanent magnet group; 231. Permanent magnet; 111. Stator teeth; 112. Stator yoke; 113. Stator slot; 25. Positioning slot; 24. Positioning block; DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application 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 application and are not used to limit the present application.

[0028] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "first" and "second" are only used for the purpose of convenience of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0029] See also Figures 1 to 3 The embodiment of the present application provides a rotor structure 20 and a magnetic field modulation permanent magnet motor 100 having the same, and the rotor structure 20 can cooperate with the stator structure 10. It can be understood that the stator structure 10 has an armature winding.

[0030] The rotor structure 20 includes: a rotor core 21, a rotor auxiliary tooth 22, and a permanent magnet group 23 arranged in the rotor core 21; it can be understood that the stator structure 10 has an installation cavity, the rotor core 21 is located in the installation cavity of the stator structure 10, and there is a gap between the rotor core 21 and the inner wall of the installation cavity. The permanent magnet group 23 is arranged in plurality, and each permanent magnet group 23 is arranged at intervals around the circumference of the rotor core 21, one end of the auxiliary tooth is connected to the side surface of the rotor core 21, and the other end of the auxiliary tooth extends toward the stator structure 10 and has a gap with the stator structure 10, and the rotor auxiliary teeth 22 are arranged in plurality at intervals around the circumference of the rotor core 21.

[0031] See also Figures 1 to 3 The rotor structure 20 provided in this embodiment includes a rotor core 21, rotor auxiliary teeth 22 and a permanent magnet group 23 arranged in the rotor core 21. The rotor auxiliary teeth 22 can change the magnetic circuit of the armature magnetic field in the stator structure 10, increase the magnetic field generated by the armature current, and at the same time, the magnetic focusing effect of the permanent magnet group 23 can significantly increase the permanent magnetic field, thereby improving the torque and torque density of the magnetic field modulation permanent magnet motor.

[0032] Optionally, the rotor auxiliary teeth 22 are arranged at equal intervals on the rotor core 21 so that the magnetic field in each magnetic pole region is evenly distributed, which helps to reduce the cogging torque and vibration and improve the stability and operation accuracy of the magnetic field modulation permanent magnet motor.

[0033] See also Figures 1 to 3 It can be understood that the rotor auxiliary teeth 22 can guide and concentrate the magnetic flux generated by the permanent magnet group 23, form a more effective magnetic circuit between the stator structure 10 and the rotor structure 20, and reduce magnetic leakage. More magnetic flux can pass through the air gap into the stator structure 10, thereby increasing the electromotive force of the armature winding 12 on the stator structure 10, and further increasing the torque and output power of the magnetic field modulation permanent magnet motor 100.

[0034] The rotor auxiliary teeth 22 help guide the magnetic flux to better couple with the armature winding 12 of the stator structure 10 and reduce the leakage magnetic loss.

[0035] See also Figures 1 to 3The rotor auxiliary teeth 22 also help to enhance the magnetic field strength in the air gap. A stronger air gap magnetic field will improve the electromagnetic coupling efficiency between the rotor structure 20 and the stator structure 10, so that the magnetic field modulation permanent magnet motor 100 can generate a larger electromotive force under the same input conditions. A higher air gap magnetic field can increase the induced current generated by the armature winding 12 of the stator structure 10 when cutting the magnetic field lines, thereby improving the electromagnetic torque and output power of the magnetic field modulation permanent magnet motor 100.

[0036] See also Figures 1 to 3 The rotor auxiliary teeth 22 can optimize the magnetic field distribution, reduce the torque pulsation caused by the tooth slot effect, enable the magnetic field modulation permanent magnet motor 100 to output power more smoothly, and reduce energy waste during operation.

[0037] See also Figures 1 to 3 In some embodiments, the rotor auxiliary teeth 22 are provided between any two adjacent permanent magnet groups 23 .

[0038] Optionally, the rotor auxiliary teeth 22 are arranged between adjacent permanent magnet groups 23, which can effectively guide the magnetic flux through the air gap to form a more uniform and concentrated magnetic field distribution. The magnetic flux generated by the permanent magnet group 23 is better guided by the rotor auxiliary teeth 22, reducing the diffusion and leakage of the magnetic flux.

[0039] The rotor auxiliary teeth 22 are arranged between two adjacent permanent magnet groups 23, which can also improve the utilization rate of magnetic flux. It can avoid the possibility of magnetic leakage or ineffective magnetic field in the area between the two permanent magnet groups 23, and the rotor auxiliary teeth 22 fill this gap, so that the magnetic flux in this area is more effectively conducted to the stator structure 10.

[0040] The existence of the rotor auxiliary teeth 22 can smooth the change of the magnetic field of the rotor structure 20, reduce the sudden change of the magnetic field caused by the gap between the permanent magnet groups 23, avoid the uneven or discontinuous magnetic field distribution inside the magnetic field modulation permanent magnet motor 100, improve the stability of the output torque of the magnetic field modulation permanent magnet motor 100, and reduce torque pulsation. In some embodiments, the permanent magnet group 23 is provided between any two adjacent rotor auxiliary teeth 22.

[0041] See also Figures 1 to 3 Optionally, the permanent magnet group 23 is arranged between adjacent rotor auxiliary teeth 22, so that the magnetic flux is more effectively concentrated and guided. The rotor auxiliary teeth 22 can effectively limit the diffusion of the magnetic flux and concentrate it in the magnetic field generated by the permanent magnet group 23, thereby enhancing the strength and concentration of the magnetic field.

[0042] The rotor auxiliary teeth 22 around the permanent magnet group 23 can effectively shield and guide the magnetic flux and reduce the leakage of the magnetic field.

[0043] By placing the permanent magnet group 23 between the rotor auxiliary teeth 22, the magnetic flux can be better constrained, thereby minimizing the magnetic leakage phenomenon and enhancing the electromagnetic performance of the motor.

[0044] Please refer to Figures 1 to 3 , in some embodiments, the number of the rotor auxiliary teeth 22 is twice the number of the permanent magnet groups 23. Among them, each permanent magnet group 23 is correspondingly provided with a rotor auxiliary tooth 22.

[0045] Please refer to Figures 1 to 3 , in some embodiments, the thickness of the rotor core along its radial direction is L1, and the thickness of the rotor auxiliary tooth along the radial direction of the rotor core is L2, where L2 is greater than zero and less than 1 / 3 * L1.

[0046] Optionally, 0 < L2 < 1 / 3 * L1, that is, the thickness of the rotor auxiliary tooth 22 being less than one-third of the thickness of the rotor core 21 can optimize the magnetic coupling between the rotor structure 20 and the stator structure 10, and can also effectively reduce the cogging effect.

[0047] Please refer to Figures 1 to 3 , in some embodiments, the cross-sectional shape of the rotor auxiliary tooth 22 is polygonal, semi-circular or semi-elliptical. It can be understood that the polygon can be a quadrilateral or a pentagon, and the shape of the quadrilateral can be a square, a rectangle or a trapezoid. In this embodiment, the cross-sectional shape of the rotor auxiliary tooth 22 is rectangular. In other embodiments, it can be selected according to the actual situation and is not limited here.

[0048] Please refer to Figures 1 to 3 , in some embodiments, a positioning groove 25 is formed on the side surface of the rotor core 21. The cross-sectional shape of the positioning groove 25 is V-shaped. The permanent magnet group 23 includes two permanent magnets 231. The two permanent magnets 231 are respectively attached to the two side walls of the positioning groove 25, so that the two permanent magnets 231 are arranged in a V shape, and an included angle is formed between the two permanent magnets 231.

[0049] Optionally, the range of the included angle is 0 to 180 degrees, that is, the included angle can be 10 degrees, 20 degrees, 30 degrees, 44 degrees, 54 degrees, 97 degrees, 120 degrees, 135 degrees, 154 degrees, 170 degrees, which is not limited here and can be selected according to the actual situation.

[0050] Please refer to Figures 1 to 3 , optionally, the magnetization direction of the permanent magnet 231 is perpendicular to the groove wall of the positioning groove 25, and the magnetization directions of the two permanent magnets 231 can both point into the included angle, that is, point into the positioning groove 25.

[0051] Please refer to Figures 1 to 3Optionally, the magnetizing direction of the permanent magnet 231 is perpendicular to the slot wall of the positioning slot 25 , and the magnetizing directions of the two permanent magnets 231 may both point outside the angle, that is, outside the positioning slot 25 .

[0052] Optionally, the two permanent magnets 231 arranged in a V-shape have a good “magnetic focusing effect”, which can increase the air gap magnetic field generated by the permanent magnets 231 , thereby improving the torque / torque density of the magnetic field modulation permanent magnet motor 100 .

[0053] See also Figures 1 to 3 In some embodiments, the rotor structure 20 further includes a positioning block 24 disposed between the two permanent magnets 231 , and the rotor auxiliary teeth 22 are connected to the positioning block 24 .

[0054] Optionally, two surfaces of the positioning block 24 disposed opposite to each other respectively abut against two permanent magnets 231 , and the positioning block 24 and the corresponding rotor auxiliary teeth 22 are integrally formed to reduce the manufacturing cost and improve the convenience of assembling the rotor structure 20 .

[0055] See also Figures 1 to 3 The present invention also proposes a magnetic field modulation permanent magnet motor 100, which includes a rotor structure 20. The specific structure of the rotor structure 20 refers to the above embodiment. Since the magnetic field modulation permanent magnet motor 100 adopts all the technical solutions of all the above embodiments, it also has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0056] See also Figures 1 to 3 In some embodiments, the magnetic field modulation permanent magnet motor 100 also includes the stator structure 10, the stator structure 10 includes a stator core 11 and a plurality of armature windings 12 arranged on the stator core 11, each of the armature windings 12 is arranged at intervals along the circumference of the stator core 11, and the rotor core 21 is located inside the stator core 11.

[0057] See also Figures 1 to 3 Optionally, the stator core 11 includes a stator yoke 112 and a plurality of stator teeth 111 arranged on the stator yoke 112, any two adjacent stator teeth 111 and the stator yoke 112 together form a stator slot 113, and the armature winding 12 is arranged in the stator slot 113 according to the pole pair number Pw and symmetrical alternating current is passed through it.

[0058] The stator core 11 is formed by axially stacking high-magnetic-permeability silicon steel sheets.

[0059] The rotor core 21 and the rotor auxiliary teeth 22 are integrally formed to simplify the assembly process, and are formed by axially stacking high-magnetic-permeability silicon steel sheets.

[0060] The material of the permanent magnet 231 is a neodymium iron boron permanent magnet material with high magnetic energy product.

[0061] See also Figures 1 to 3 In some embodiments, the stator core 11 has Zs stator slots 113 corresponding to Zs stator teeth 111, and each armature winding 12 is arranged in each stator slot 113 according to the pole pair number Pw. The number of the rotor auxiliary teeth 22 is Zr, and Pw = |Zs-Zr / 2|.

[0062] Optionally, in this embodiment, the number of stator teeth 111 is Zs=12; the number of pole pairs of the armature winding 12 is Pw=2; the number of rotor auxiliary teeth 22 is Zr=20, and the number of permanent magnet groups 23 is Zr / 2=10. The magnetization direction of the permanent magnet 231 is all outward along the V-shaped opening, and the number of magnet pole pairs formed is also Zr / 2=10.

[0063] like Figure 4 As shown, the three-phase armature winding 12 adopts a single-layer winding and is wound and connected according to the pole pair number Pw=2.

[0064] See also Figure 5 , Figure 5 The air gap flux density generated by the armature current of the magnetic field modulation permanent magnet motor 100 in the embodiment of the present application and the magnetic field modulation permanent magnet motor without rotor auxiliary teeth and the harmonic spectrum corresponding to the air gap flux density are compared.

[0065] from Figure 5 (a) It can be seen that under the magnetic field modulation effect of the stator teeth 111 and the rotor auxiliary teeth 22, the air gap magnetic density waveforms of the magnetic field modulation permanent magnet motor 100 provided in the embodiment of the present application and the magnetic field modulation type permanent magnet motor without rotor auxiliary teeth are both non-sinusoidally distributed and both contain many harmonics, but the air gap magnetic density generated by the armature current in the embodiment of the present application is significantly greater than the air gap magnetic density generated by the magnetic field modulation type permanent magnet motor without rotor auxiliary teeth.

[0066] from Figure 5 (b) It can be seen that since the armature winding 12 of the magnetic field modulation permanent magnet motor 100 and the magnetic field modulation permanent magnet motor without rotor auxiliary teeth in the embodiment of the present application are both in accordance with Figure 4 The poles shown are wound and connected, so the number of pole pairs of the fundamental magnetic field generated is 2, which is Figure 5 (b) The place corresponding to the maximum amplitude.

[0067] Continue to refer Figure 5(b), due to the magnetic field modulation effect, the fundamental magnetic field of the armature current 2 pairs of poles is modulated by the 12 stator teeth 111 into the magnetic field harmonics of 10 pairs of poles, that is, the place corresponding to the second largest amplitude. According to the principle of the magnetic field modulation type motor, the fundamental magnetic field of the 2 pairs of poles and the harmonic magnetic field of the 10 pairs of poles both participate in the output of the torque. In this embodiment, the fundamental magnetic field of the 2 pairs of poles and the harmonic magnetic field of the 10 pairs of poles have amplitudes greater than those of the magnetic field modulation type permanent magnet motor without rotor auxiliary teeth. Therefore, the magnetic field modulation permanent magnet motor 100 of this embodiment can significantly increase the magnetic field generated by the armature current by introducing the rotor auxiliary teeth 22, thereby improving the torque of the magnetic field modulation permanent magnet motor 100.

[0068] Figure 6 The cogging torque of the magnetic field modulation permanent magnet motor 100 of this embodiment is compared with that of the magnetic field modulation permanent magnet motor without rotor auxiliary teeth. Figure 6 It can be seen that the magnetic field modulation permanent magnet motor 100 of this embodiment can significantly reduce the cogging torque due to the introduction of the rotor auxiliary teeth 22 .

[0069] Figure 7 The output torque of the magnetic field modulation permanent magnet motor 100 of this embodiment is compared with that of the magnetic field modulation permanent magnet motor without rotor auxiliary teeth under the same speed and the same current. Figure 7 It can be seen that the magnetic field modulation permanent magnet motor 100 of this embodiment has significantly higher output torque than the magnetic field modulation permanent magnet motor without rotor auxiliary teeth.

[0070] This embodiment is only an example for clear explanation and is not a limitation of the implementation method. For those skilled in the art, the number Zs of the stator slots 113 and the number Zr of the rotor auxiliary teeth 22 can be flexibly adjusted to realize the field modulation permanent magnet motor 100 with slot-pole combination.

[0071] In addition, many types of magnetic field modulation permanent magnet motors can be derived according to different winding connection methods. Other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the invention.

Claims

1. A rotor structure, matched with a stator structure, characterized in that: The rotor structure includes: a rotor core, rotor auxiliary teeth and a permanent magnet group arranged in the rotor core; the rotor core is located in the stator structure, a plurality of permanent magnet groups are arranged, each of the permanent magnet groups is arranged at intervals around the circumference of the rotor core, one end of the auxiliary teeth is connected to the side surface of the rotor core, the other end of the auxiliary teeth extends toward the stator structure and has a gap with the stator structure, and a plurality of rotor auxiliary teeth are arranged at intervals around the circumference of the rotor core.

2. The rotor structure according to claim 1, characterized in that: The rotor auxiliary teeth are arranged between any two adjacent permanent magnet groups.

3. The rotor structure according to claim 1, characterized in that: The permanent magnet group is arranged between any two adjacent rotor auxiliary teeth.

4. The rotor structure according to claim 1, characterized in that: The number of the rotor auxiliary teeth is twice the number of the permanent magnet groups.

5. The rotor structure according to claim 1, characterized in that: The thickness of the rotor core along the radial direction is L1, and the thickness of the rotor auxiliary teeth along the radial direction of the rotor core is L2, and L2 is greater than zero and less than 1 / 3*L1.

6. The rotor structure according to any one of claims 1 to 5, characterized in that: The cross-sectional shape of the rotor auxiliary teeth is polygonal, semicircular or semi-elliptical.

7. The rotor structure according to any one of claims 1 to 5, characterized in that: A positioning groove is provided on the side surface of the rotor core, and the permanent magnet group includes two permanent magnets. The two permanent magnets are respectively attached to the two side walls of the positioning groove, and there is an angle between the two permanent magnets, and the magnetization directions of the two permanent magnets point inside the angle or outside the angle.

8. The rotor structure according to claim 7, characterized in that: The rotor structure also includes a positioning block arranged between the two permanent magnets, and the rotor auxiliary teeth are connected to the positioning block.

9. A magnetic field modulation permanent magnet motor, characterized in that: Comprising the rotor structure as described in any one of claims 1-8, the magnetic field modulation permanent magnet motor also includes the stator structure, the stator structure includes a stator core and a plurality of armature windings arranged on the stator core, each of the armature windings is arranged at intervals along the circumference of the stator core, and the rotor core is located inside the stator core.

10. The magnetic field modulation permanent magnet motor according to claim 9, characterized in that: The stator core is provided with Zs stator slots, each armature winding is arranged in each stator slot according to the number of pole pairs Pw, the number of the rotor auxiliary teeth is Zr, and Pw=|Zs-Zr / 2|.

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