JP7630308B2 - Stator, method of manufacturing stator, method of manufacturing AC rotating electric machine, induction motor and blower - Google Patents

Description

This application relates to a stator, a method for manufacturing a stator, a method for manufacturing an AC rotating electric machine, an induction motor, and a blower.

In an electric motor, the coil ends outside the stator core are not linked to the magnetic circuit. As a result, the magnetic flux generated by the coil ends becomes leakage flux, which not only reduces the power factor but also increases the coil circumference and increases resistance. Therefore, it is important to reduce the number of coil ends.

In typical electric motors, the coil is inserted between the slots using an insert method, so there needs to be some margin in the coil circumference, which is known to result in large coil ends. To lower the coil ends, there is a method in which the stator core is divided into an outer ring yoke section and an inner ring magnetic pole section, and the coil is wound directly around the insulating material of the inner ring magnetic pole section (see, for example, Patent Document 1).

In addition, by using a stator core divided into partial circles that form part of the stator core, it is possible to apply it to lap windings with lower coil ends (see, for example, Patent Document 2).

Japanese Patent Application Publication No. 6-6959 JP 2009-254133 A

As mentioned above, in distributed winding motors, the fixed core can be divided into an inner ring and an outer ring to create lap winding with low coil ends, but it is difficult to further reduce the height and circumference of the coil ends. In addition, because the teeth are separate, there is the issue that handling is difficult, including determining the position of each one.

This application has been made to solve the problems described above, and aims to provide a stator that allows the coil ends to be made low-profile, a method for manufacturing a stator, a method for manufacturing an AC rotating electric machine, an induction motor, and a blower.

The stator disclosed in the present application is
The coil is arranged so that the distance between a first coil end protruding from one surface of the inner core and the one surface is longer than the distance between a second coil end protruding from the opposite surface of the inner core and the opposite surface, and the coil is inserted into a slot formed between adjacent inner core pieces, and a ring-shaped outer core connecting the outer diameters of the multiple inner core pieces, the coil being arranged so that the distance between a first coil end protruding from one surface of the inner core and the one surface is longer than the distance between a second coil end protruding from the opposite surface of the inner core and the opposite surface ,
a space between one surface of the inner core and the first coil end has a length that allows the inner core to be bent toward the outer diameter side, and the second coil end is disposed linearly along the opposite surface of the inner core;
a portion of the second coil end is disposed inside an inner diameter of the annular inner core,
The first coil end is characterized in that it is bent toward the outer diameter side of the inner core so as not to hinder axial insertion of the rotor, and is positioned outside the inner diameter of the annular inner core .

The stator disclosed in this application allows the coils to be arranged so that the distance between the first coil end protruding from one surface of the inner core and that surface is longer than the distance between the second coil end protruding from the opposite surface of the inner core and the opposite surface, thereby making it possible to reduce the height of the coil ends.

FIG. 2 is a top view of the stator core. 2 is a top view of the inner core and the outer core that constitute the stator core. FIG. 4 is a side view of the linear inner core according to the first embodiment. FIG. 4 is a diagram showing two adjacent inner cores according to the first embodiment as viewed from the inner diameter side. FIG. 5A to 5C are diagrams illustrating the shape of a coil according to the first embodiment. 5A to 5C are diagrams illustrating the insertion of a coil into a linear inner core in accordance with the first embodiment. 5A to 5C are diagrams illustrating the insertion of a coil into a linear inner core in accordance with the first embodiment. 6A to 6C are diagrams illustrating a process for forming a linear inner core into an annular shape in accordance with the first embodiment. 5A to 5C are diagrams illustrating the arrangement of coils relative to an inner core in the first embodiment. 10A to 10C are diagrams illustrating the coil insertion process after the inner core in the first embodiment is formed into a circular ring shape. 3 is a diagram showing a configuration of a stator according to the first embodiment; FIG. 4 is a diagram showing the coil in the slot according to the first embodiment as viewed from both sides of the annular inner core. FIG. 5A to 5C are diagrams illustrating the relationship between the stator, an inner diameter jig, and a coil according to the first embodiment. 5A to 5C are diagrams illustrating a configuration in which a coil end according to the first embodiment is tilted toward the outer diameter side of an inner core. 2 is a top view of the rotor according to the first embodiment. FIG. 2 is a diagram showing a state in which a rotor is inserted into a stator according to the first embodiment, as viewed from above. FIG. 4 is a diagram showing a die layout for a stator core and a rotor core according to the first embodiment; FIG. 5A to 5C are diagrams illustrating a state in which a stator core and a rotor core according to the first embodiment have been punched together. 1 is a diagram illustrating a configuration of an induction motor using a stator according to a first embodiment. FIG. FIG. 2 is a side view of a blower using the stator according to the first embodiment. 10A to 10C are diagrams illustrating the configuration of a linear outer core according to a second embodiment. 13 is a view showing two adjacent outer cores according to a second embodiment as viewed from the inner diameter side. FIG. 13 is a diagram illustrating a die layout for a linear outer core according to the second embodiment. FIG. 13 is a diagram illustrating a die layout for a linear inner core according to the second embodiment. FIG. 10A and 10B are diagrams illustrating the structure of the inner diameter side of an outer core in accordance with embodiment 2. FIG. 11 is a top view of a stator according to a second embodiment. 13A and 13B are diagrams illustrating the shape of teeth of an inner core according to a second embodiment. 13 is a diagram illustrating the layout of a mold for a linear inner core and an outer core divided into four parts in accordance with embodiment 3. FIG. 13A to 13C are diagrams illustrating the positions of holes formed in an outer core divided into four parts according to embodiment 3. 13 is a diagram illustrating the stacking of the outer core divided into four parts according to the third embodiment. FIG. FIG. 11 is a top view of a stator according to a third embodiment.

Below, a preferred embodiment of the stator according to the present application will be described with reference to the drawings. Note that the same reference numerals are used for the same contents and corresponding parts, and detailed explanations thereof will be omitted. Similarly, in the following embodiments, redundant explanations of configurations with the same reference numerals will be omitted.

First embodiment
Fig. 1 shows a stator core 3 which is divided into an inner core 1 and an outer core 2. That is, as shown in Fig. 2(a) and (b), this core structure is formed by inserting a preformed coil into the inner core 1 by dropping it from the outer diameter side or the inner diameter side, or by winding the coil directly onto the inner core 1, and then connecting the annular outer core 2 to the inner core 1 to form the stator core 3 shown in Fig. 1.

In contrast, the inner core 4 of the stator shown in Figure 3 is arranged in a straight line with adjacent inner core pieces 4a connected by a thin-walled portion 5 at the tip end on the inner diameter side. With this structure, a slot 6 is formed between adjacent inner core pieces 4a into which a coil is inserted. The inner core 4 is punched out of a roll of electromagnetic steel sheet using a die press. The grade of the electromagnetic steel sheet is not limited here.

Figure 4 shows two adjacent inner core pieces 4a viewed from the inner diameter side. The inner core 4 is formed by stacking thin plates 7 of electromagnetic steel. The thin-walled portion 5 connecting adjacent inner core pieces 4a may be formed from one or more of the stacked thin plates 7, and may be formed from any layer of the stack. The thickness of the thin plates is not limited here. Methods such as crimping or adhesive are known for fixing the thin plates 7 between the stacks, but are not limited here.

Next, the shape of the coil 8 to be inserted into each slot 6 will be explained with reference to Figure 5. The coil 8 is formed in advance by winding magnet wire around a reel or the like. In this embodiment, round copper wire is used as the magnet wire. Various types and wire diameters of magnet wire can be used depending on the size of the stator, the type of electric motor, etc.

As shown in FIG. 6, in this embodiment, the coil 8 is inserted into a predetermined slot 6 from the right side of the figure so as to form a lap winding in a 16-slot stator. Here, for ease of explanation, the coil 8 is shown with one turn of winding between the slots. For convenience, this representation may also be used in other figures.

As shown in FIG. 7, each of the inner core pieces 4a is arranged in a straight line and perpendicular to the coil 8, making insertion easy. As mentioned above, the inner core pieces 4a are also connected by the thin-walled portion 5, making it easy to manipulate the inner core 4 during insertion.

Next, with coils 8 inserted into all slots 6, as shown in Figure 8, the inner diameter side of the inner core 4 is aligned with the outer periphery of the inner diameter jig 11 from the side where one layer of coils 8 is inserted (the left side of Figure 6), and the inner core 4 connected by the thin-walled portion 5 is rotated around the inner diameter jig 11. During rotation, the thin-walled portion 5 bends and moves along the inner diameter jig 11, connecting and rotating each inner core piece 4a. For this reason, it is necessary for the thin-walled portion 5 to have a width large enough that it will not break due to the stress of a single bend.

When the inner core 4 is rotated, the coils 8 inserted in each slot 6 shown in FIG. 9(a) are pulled to one side by applying a force in the direction of arrow A (perpendicular to one surface of the inner core 4) in the cylindrical axial direction (height 9 direction) of the inner diameter jig 11 as shown in FIG. 9(b). As a result of being pulled, the coils 8 are deformed, and the length of the coils 8 in the circumferential direction 10 also changes according to the pulling force in the direction of arrow A.

In other words, the coil 8 sticks to the inner core piece 4a, and the length of the coil end on the side being pulled in the direction of arrow A becomes longer than the opposite side, forming a gap 12 between the inner core piece 4a and the coil 8. In order to pull the coil 8, when the coil 8 is formed in advance on the winding frame, it is necessary to form the length of the coil 8 with a margin larger than the sum of the circumferential direction 10 and height 9 of the multiple inner core pieces 4a into which the coil 8 is inserted.

As shown in FIG. 8, when the inner core 4 is rotated along the inner diameter jig 11, the coil 8 overlaps above the inner diameter jig 11, so the height of the inner diameter jig 11 must be equal to or lower than the axial height 9 of the inner core 4 laminated with thin plates 7. Also, although not shown in the figure, it is sufficient that the support portion, which is the axis of rotation of the rotating inner diameter jig 11, does not come into contact with the coil 8. Here, we will not go into detail about the support portion of the inner diameter jig 11.

When the inner core 4 is shaped into a ring along the inner diameter jig 11, the inner core pieces 4a that are not connected by the thin-walled portion 5 shown in FIG. 4 come into contact with each other, forming a joint 13 as shown in FIG. 10. The joint 13 is joined to complete the ring-shaped inner core 4. The method for joining the inner core pieces 4a together is not limited here.

When the inner core 4 becomes annular, the coils 8 not yet inserted in the slots 6 shown on the right side of FIG. 6 are inserted as shown by the arrows in FIG. 10 into the slots 6 where only one layer of coils 8 was inserted as shown on the left side of FIG. 8, until all of the coils 8 are inserted into the slots 6. Next, the outer core 14 is pressed into the outer diameter side of the annular inner core 4, forming a stator 15 as shown in FIG. 11. In FIG. 11, the windings in the direction connecting the slots of the coils 8 are omitted.

In the stator 15 thus formed, the side of the coil 8 shown in FIG. 9(b) on which the coil end protruding from one side of the inner core 4 is longer is shown in FIG. 12(a) as the side 16 on which the core bar or rotor is inserted, and the opposite side is shown in FIG. 12(b) as the side 17 on which the rotor is not inserted. In FIG. 12(a), the coil ends passing through the inner diameter side in the slot are arched, and the coil ends are located with a gap 12 from one side of the inner core 4. In contrast, in FIG. 12(b), the coil ends passing through the inner diameter side in the slot on the side 17 on which the rotor is not inserted are arranged in a straight line along the opposite side of the inner core 4. However, in both the side 16 on which the rotor is inserted and the side 17 on which the rotor is not inserted, the coil ends are present on the inner diameter side of the slot, that is, above the inner diameter jig 11, as shown in FIG. 13, so the inner diameter jig 11 cannot be removed in this state.

As shown in FIG. 14, the coil end on the rotor insertion side 16 is tilted toward the outer diameter side of the stator 15, making it possible to remove the inner diameter jig 11. That is, each of the coil ends of the coil 8 on the rotor insertion side 16 that has been pulled toward the outer diameter side of the inner core 4 is bent. The force required to bend the coil ends varies depending on the size of the gap 12 between the coil ends and the inner core 4, so appropriate adjustments are required. When bending the coil ends, a mirror finish is applied to the bending jig used to bend the coils 8 without destroying their insulating coating, and the bending speed must also be adjusted, but this is not limited to this and will not be described in detail here.

In this way, compared to when all of the coil ends on both sides of the stator 15, the side 16 where the rotor is inserted and the side 17 where the rotor is not inserted, are arranged above the inner core 4 with a certain amount of gap, the coil ends on the side 17 where the rotor is not inserted are arranged in a straight line passing through the inner diameter side within the slot, and only the coil ends on the side 16 where the rotor is inserted are arranged above the inner core 4 with a gap, which shortens the circumference of the coil 8, leading to a shorter axial length of the motor and a reduction in weight due to a reduction in the amount of copper.

In this embodiment, the outer core 14 is pressed into the inner core 4 with the inner diameter jig 11 placed inside the stator 15, but it is also possible to tilt the coil end before pressing in the outer core 14, remove the inner diameter jig 11 once, and then insert a dedicated core bar that supports the inner diameter of the inner core 4 to increase the pressing accuracy or to divide the process, and then press in the outer core 14.

In addition, when rotating the inner core 4 connected by the thin-walled portion 5 while aligning the inner diameter side of the inner core 4 with the inner diameter jig 11, the coil ends may be tilted toward the outer diameter side while pulling the coils 8 inserted in each slot 6 to one side in the axial direction 9 of the coil, as shown in FIG. 9(b).

With the coil end on one side in the axial direction tilted, the rotor 18 shown in FIG. 15 is inserted into the stator 15. The rotor 18 is made by forming an aluminum bar by aluminum die casting into a cage-shaped rotor core 19, pressing the shaft 20 into it, and attaching bearings to both ends of the shaft, but the detailed structure of the rotor 18 is not limited here.

As shown in FIG. 16, after inserting the rotor 18, the frame and bracket that cover the stator 15 and the rotor 18 are attached, but depending on the structure of the frame and bracket, the coil end on one side that is tilted to the outer diameter side may be returned to above the rotor 18. In addition, the coil end on the side 16 where the rotor is inserted may be fixed with varnish or lacing as necessary to prevent it from moving. The coil end on the side 17 where the rotor is not inserted is straight with little slack on the inner diameter side, but may also be fixed with varnish or lacing as necessary to prevent it from moving. In addition, although not described in detail in this embodiment, an insulating member for insulating the electromagnetic steel plate and the coil 8 may be attached to each inner core piece 4a before inserting the coil 8.

The inner core 4 and the outer core 14 are formed by punching out rolled electromagnetic steel sheet material with a die. As shown in Fig. 17, the outer core 14, the annular inner core 4, and the rotor core 19 are punched together. This punching improves the fit between the outer core 14 and the inner core 4 when they are press-fitted together. After punching, as shown in Fig. 18, one location of the thin-walled portion 5 of the annular inner core 4 is cut off and aligned in a straight line, and the coil 8 is inserted or directly wound.
In addition, since the inner cores 1 shown in FIG. 1 have gaps between adjacent inner cores on the inner diameter side, after inserting the coils and forming the stator core 3, the work of inserting wedges to prevent the inserted coils from leaking out to the inner diameter side is required. However, in this embodiment, the inner cores 4 are connected by thin-walled portions 5, so that the coils 8 will not leak out to the inner diameter side, and therefore the work of inserting wedges is not required.

By mounting the stator 15, it is possible to provide an induction motor 31 that has a low coil end, is highly efficient, lightweight, and easy to manufacture, as shown in FIG. 19. By mounting this induction motor 31 on a blower 32, for example, as shown in FIG. 20, it is possible to provide an energy-saving ventilation fan.

Embodiment 2
The stator structure and manufacturing method according to embodiment 2 will be described below. In embodiment 1, the outer core 14 was an annular one-piece body, but in embodiment 2, as shown in Fig. 21, like the inner core 4 in embodiment 1, divided outer core pieces 21a are arranged in a straight line in the same number as the inner core pieces 4a, and each outer core piece 21a is connected by a thin portion 22 at the tip part on the outer diameter side. As shown in Fig. 22, like the inner core pieces 4a, the outer core pieces 21a are formed by laminating thin electromagnetic steel sheets 23.

As shown in Figures 23 and 24, the inner core 24 and outer core 21 are punched out using a die press, and the inner core 24 and outer core 21 connected in a daisy chain are separated at the thin-walled portions 22 as many as necessary and stacked to form the inner core 24 and outer core 21. The thin-walled portions 22 connecting adjacent outer core pieces 21a need only be formed from one or more of the stacked thin plates 23, and may be formed from any of the stacked layers. The thickness of the thin plates 23 is not limited here. Methods such as caulking and adhesive are known for fixing the thin plates 23 between the layers, but are not limited here.

After the inner core 24 is shaped into a ring, the outer core 21, which is also arranged in a straight line, is formed into a ring. When shaping the outer core 21 into a ring, the position is determined by the contact surfaces between the outer core pieces 21a, so the jig used to shape the inner core 24 into a ring is not required, but may be used depending on the desired accuracy.

The inner core 24 and the outer core 21 are made into an annular shape, and the parts that are not connected by the thin-walled parts 22 are joined together. If the joints of the inner core 24 and the outer core 21 are at the same circumferential position, the mechanical strength may be reduced. Therefore, the circumferential positions of the inner core 24 and the outer core 21 are determined so that the joints of the inner core 24 and the outer core 21 are at different positions. In addition, as shown in Figures 25(a) and (b), a positioning groove may be provided on the inner diameter of the outer core 21 at the part where the outer diameter side of the inner core 24 and the inner diameter side of the outer core 21 contact, or as shown in Figure 25(c), a concave-convex groove may be provided in which the inner core 24 and the outer core 21 fit together. The annular inner core 24 and the outer core 21 are pressed into each other to form a stator 25 as shown in Figure 26. The coil insertion and coil end bending are the same as those described in the first embodiment.

As described above, when the outer core 21 and the inner core 24 of the second embodiment are punched out by a die press, their shapes are linear, and the outer core 21 is positioned parallel to the rolling direction of the electromagnetic steel sheet as shown in FIG. 23. Also, the inner core 24 is positioned perpendicular to the rolling direction of the electromagnetic steel sheet as shown in FIG. 24.

This is because the electromagnetic steel sheet used is oriented electromagnetic steel sheet, which has extremely excellent magnetic properties only in the rolling direction. As a result, magnetic flux flows in the circumferential direction of the outer core 21 when it is made into a ring shape, so by arranging it in a straight line and parallel to the rolling direction, it is possible to obtain excellent magnetic properties in the circumferential direction of the outer core 21 when it is made into a ring shape.

Similarly, when the inner core 24 is formed into a ring shape, a large amount of magnetic flux flows through each of the teeth 26 shown in FIG. 27. Therefore, by arranging them in a line and perpendicular to the rolling direction, excellent magnetic properties can be obtained in the teeth 26 of each inner core 24 when formed into a ring shape, and the leakage magnetic flux flowing through the thin-walled portion 27 of the inner core 24 can be reduced, making it possible to further improve the efficiency of an induction motor equipped with the stator 25 of this embodiment. In addition, the inner core 24 and outer core 21 are arranged in a line, and there are few gaps between them, making it possible to arrange them in a mold, resulting in extremely high yields.

Embodiment 3
The stator structure and manufacturing method according to embodiment 3 will be described below. While outer core 14 in embodiment 1 is an annular one-piece body, embodiment 3 uses outer core pieces 28a obtained by dividing an annular outer core into four as shown in Fig. 28. In this embodiment, the grade of the electromagnetic steel sheet is not limited.

By dividing the outer core 28 into four parts, the outer core pieces 28a can be positioned in the die with fewer gaps, and the inner core 29 can also be positioned in the die with fewer gaps, resulting in a high yield. The outer core pieces 28a can be connected to each other by providing them with matching grooves as described in embodiment 2, and then positioning them for connection.

Also, since the annular outer core 28 is divided into four parts as shown in FIG. 29, holes or outer circumferential grooves are provided at 45 degrees from the center of each outer core piece 28a, and the four outer core pieces 28a can be connected together by alternately stacking them every 45 degrees as shown in FIG. 30 and fixing the holes with rivets, welding to the outer circumferential grooves, or fixing with strap rivets. The four outer core pieces 28a are formed into an annular shape, and the coils are inserted into the inner core 29 and the coil ends are bent in the same manner as described in embodiment 1. The outer core 28 is pressed into the inner core as shown in FIG. 31 to form a stator.

Although the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.
Therefore, countless modifications not exemplified are assumed within the scope of the technology disclosed in the present specification, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

1, 4, 24, 29: Inner core, 2, 14, 21, 28: Outer core, 3: Stator core, 4a: Inner core piece, 5, 22, 27: Thin section, 6: Slot, 7, 23: Thin plate, 8: Coil, 11: Inner diameter jig, 12: Gap, 13: Joint, 15, 25: Stator, 18: Rotor, 19: Rotor core, 20: Shaft, 21a, 28a: Outer core piece, 26: Teeth section, 31: Induction motor, 32: Blower

Claims (12)

the coil is arranged such that a distance between a first coil end protruding from one surface of the inner core and the one surface is longer than a distance between a second coil end protruding from the opposite surface of the inner core and the opposite surface ,
a space between one surface of the inner core and the first coil end has a length that allows the inner core to be bent toward an outer diameter side, and the second coil end is disposed linearly along an opposite surface of the inner core,
a portion of the second coil end is disposed inside an inner diameter of the annular inner core,
A stator characterized in that the first coil end is bent toward the outer diameter side of the inner core so as not to interfere with axial insertion of the rotor, and is positioned outside the inner diameter of the annular inner core . 2. The stator according to claim 1 , wherein the outer core is formed by laminating thin electromagnetic steel sheets and connecting a plurality of outer core pieces via thin portions. A method for manufacturing a stator, comprising stacking thin sheets of electromagnetic steel, linearly arranging a plurality of inner core pieces connected to each other via thin portions, inserting a coil formed by winding a predetermined number of turns into a slot formed between adjacent inner core pieces, and before joining the linearly arranged inner core pieces at both ends to form an annular inner core, pulling the coil in a direction perpendicular to one face of the inner core to deform the coil so that the distance between a first coil end protruding from one face of the inner core and the one face is longer than the distance between a second coil end protruding from the opposite face of the inner core and the opposite face. 4. The method for manufacturing a stator according to claim 3 , further comprising press-fitting an annular outer core into outer diameter ends of the inner core pieces extending in the radial direction of the annular inner core. 5. The method for manufacturing a stator as described in claim 4, characterized in that the outer core is formed by stacking thin electromagnetic steel sheets, and the same number of outer core pieces as the inner core pieces are connected in a straight line via thin-walled portions, and the outer core pieces at both ends of the straight line are joined to form a circular ring shape. 6. The method for manufacturing a stator according to claim 5 , wherein the joint portion of the annular inner core and the joint portion of the annular outer core are disposed at different positions in the circumferential direction. The method for manufacturing a stator as described in claim 5, characterized in that the electromagnetic steel sheets forming the inner core pieces and the outer core pieces are oriented electromagnetic steel sheets, and when the inner core pieces are formed by die pressing, they are arranged in a straight line perpendicular to the rolling direction and punched out, and when the outer core pieces are formed by die pressing, they are arranged in a straight line parallel to the rolling direction and punched out. 5. The method for manufacturing a stator as described in claim 4, characterized in that the annular outer core is formed by punching out four arc-shaped outer core pieces using a die press and stacking them, and connecting portions are formed to connect the four arc-shaped outer core pieces to each other. A method for manufacturing an AC rotating electric machine, comprising stacking thin sheets of electromagnetic steel, linearly arranging a plurality of inner core pieces connected to each other via thin-walled portions, inserting a coil formed by winding a predetermined number of turns into a slot formed between adjacent inner core pieces, and before joining the linearly arranged inner core pieces at both ends to form an annular inner core, pulling the coil in a direction perpendicular to one face of the inner core to deform the coil, making the distance between a first coil end protruding from one face of the inner core and the one face longer than the distance between a second coil end protruding from the opposite face of the inner core and the opposite face, and bending the first coil end toward the outer diameter of the inner core when inserting a rotor into the annular inner core. 10. The method for manufacturing an AC rotating electric machine according to claim 9 , further comprising the step of: bending the first coil end bent toward the outer diameter side of the inner core toward the inner diameter side of the inner core after inserting a rotor. An induction motor equipped with the stator according to claim 1 or 2 . A blower equipped with the induction motor according to claim 11 .

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