JP5545458B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine, and more particularly to an improvement of a brushless motor.

  Conventionally, as a method of fixing the stator to the motor case of the brushless motor, a method of press-fitting the stator (see, for example, Patent Document 1), a method of shrink-fitting the stator, and the like have been introduced. However, in the fixing method by press fitting or shrink fitting, there is a concern that the stator core, which is a constituent element of the stator, is distorted by stress and the loss torque is deteriorated.

  Therefore, as a structure for fixing a part of the stator core by press-fitting, the stator core is fastened to be inserted into the stator core in the axial direction of the stator core, and one end thereof is fixed to the motor case to fasten the stator core to the motor case. And a contact portion fixed to an axial end portion of the stator core positioned on the opposite side in the axial direction with respect to a side where the fastening portion is fixed to the motor case, and contacting an inner peripheral surface of the motor case A stator fixing structure provided with is proposed. (For example, refer to Patent Document 2).

  In addition, an electric power steering apparatus in which a damping material is inserted between the stator core and the motor case has been introduced in order to prevent the stator core from being distorted when the stator is press-fitted into the motor case. (For example, refer to Patent Document 3).

  In addition, in order to absorb the vibration of the stator and reduce the vibration noise of the motor case, the inner peripheral surface of the motor case and the outer peripheral surface of the stator are formed so as to be in non-contact with each other. A brushless motor in which an elastic member is provided between a peripheral surface and the outer peripheral surface of the stator is also introduced. (For example, refer to Patent Document 4).

  Furthermore, as another fixing method, a method of fixing the motor case and the stator with an adhesive is also introduced.

Japanese Patent No. 3881351 JP 2007-306751 A JP 2007-82378 A JP 2007-189812 A

  However, as described in Patent Document 2, a structure in which a part of the stator core is fixed by press-fitting, and as described in Patent Documents 3 and 4, a gap is provided between the stator and the motor case. In a structure in which an elastic member (damping material) is interposed in the gap, it is desired that the stator be held more securely with respect to the motor case when a reaction force due to rotational torque is applied.

  In addition, the method of fixing the stator and the motor case with an adhesive is to apply a thin adhesive in advance to the outer peripheral surface of the stator or the inner peripheral surface of the motor case, and then insert the stator into the motor case. Since the film pressure is thin, it is necessary to reduce the interval (gap) between the outer peripheral surface of the stator and the inner peripheral surface of the motor case. Therefore, the adhesive is shaved when the stator is inserted into the motor case, and the shaved adhesive is pushed by the stator and moves to the back side (bottom side) of the motor case, and the adhesive applied to the back side. Since the agent is also scraped, the protruding adhesive may be cured and become a foreign substance. For this reason, it is difficult to manage the process including management of the curing time, strength, and coating amount of the adhesive, resulting in an increase in cost.

  The present invention has been made in view of such circumstances. The stator can be reliably positioned in the axial direction with respect to the motor case, and the stator can be securely held in the motor case, and the stator core can be distorted. It is an object of the present invention to provide a rotating electrical machine that can prevent loss of torque and reduce loss torque.

  In order to achieve this object, the present invention provides a rotating electrical machine including a motor case formed in a substantially cylindrical shape, and a stator that is inserted from an insertion port of the motor case and disposed inside the motor case. An inner peripheral step is formed on the inner peripheral surface of the motor case so that the inner diameter on the insertion port side is larger than the inner diameter on the rear side, and the motor case is formed by the inner peripheral step. Provided is a rotating electrical machine having a circumferential step surface, wherein the stator has a contact surface that contacts the inner circumferential step surface, and the inner circumferential surface of the motor case and the outer circumferential surface of the stator are not in contact with each other. Is.

  In the rotating electrical machine having this configuration, the inner circumferential step surface formed on the motor case and the contact surface formed on the stator are in contact with each other. Can be positioned. Furthermore, since the inner peripheral surface of the motor case and the outer peripheral surface of the stator are not in contact with each other, no stress is applied to the stator and no distortion occurs in the stator core. Therefore, loss torque can be reduced.

  As an embodiment of the rotating device according to the present invention, the stator is configured such that an outer peripheral step that is complementary to the inner peripheral step is formed at a position facing the inner peripheral step on the outer peripheral surface of the stator. The surface may include an outer peripheral step surface formed by the outer peripheral step, and the inner peripheral step surface and the outer peripheral step surface may be in contact with each other. Alternatively, the contact surface may be an end surface on the insertion direction side of the stator (an end surface in a direction on the back side of the motor case).

  In the rotating electrical machine according to the present invention, a plurality of the inner circumferential steps are formed on the inner circumferential surface of the motor case at intervals, and the outer circumferential surfaces of the stator are opposed to the respective inner circumferential steps. The structure in which the outer periphery level | step difference was each formed can be provided.

  The rotating electrical machine according to the present invention further includes a bracket disposed on the insertion opening side of the motor case, and a large-diameter portion formed by the inner peripheral step comprises an insertion port side distal end portion of the motor case. The large-diameter portion formed by the outer circumferential step of the stator may be configured to be sandwiched between the insertion port side distal end portion of the motor case and the bracket and fastened together by a fixing member. In the case of this configuration, examples of the fixing member include a screw. When the stator and the motor case are fixed to the bracket with a screw, a screw hole formed in the stator extends along the circumferential direction of the stator. By forming the elongated hole, the stator can be moved (rotated) to some extent in the circumferential direction during assembly. Therefore, the resolver signal and the induced voltage can be easily adjusted.

  In the rotating electrical machine according to the present invention, the adhesive can be interposed between the inner peripheral surface of the motor case and the outer peripheral surface of the stator, closer to the insertion opening than the inner peripheral step surface. . By configuring in this way, the inner peripheral surface of the motor case and the outer peripheral surface of the stator can be fixed with an adhesive, so that the stator can be more reliably positioned and held in the motor case. In addition, since the adhesive is interposed on the insertion opening side of the inner peripheral step surface, even if the adhesive tries to move to the back side when the stator is inserted into the motor case, the inner peripheral The contact between the step surface and the contact surface can prevent the adhesive from moving further back. Therefore, it can prevent that the foreign material resulting from an adhesive agent exists in the back | inner side of a rotary electric machine.

  Furthermore, the rotating electrical machine according to the present invention is provided between an inner peripheral surface of the small diameter portion formed by the inner peripheral step of the motor case and an outer peripheral surface of the small diameter portion formed by the outer peripheral step of the stator. A ring member can be interposed. With this configuration, when the stator is inserted into the motor case, it is easy to ensure the coaxiality between the stator and the motor case, and the stator can be more easily inserted and positioned. In addition, since the ring member is made of an elastic member, the stator can be more easily inserted and positioned, and when vibration is applied to the rotating electrical machine, the ring member can efficiently absorb the vibration. it can.

  Further, in the rotating electrical machine according to the present invention, when the large diameter portion formed by the inner circumferential step is constituted by the insertion port side distal end portion of the motor case, the large diameter portion of the motor case and the stator An elastic member may be interposed between at least one of the large diameter portion and between the large diameter portion of the stator and the bracket. By comprising in this way, it can suppress that the vibration of a stator is propagated to a motor case and / or a bracket.

  In addition, the rotary electric machine concerning this invention can be used as motors, such as an electric power steering apparatus, for example.

It is sectional drawing along the rotating shaft direction of the motor for EPS concerning Example 1 of this invention. It is a bottom view of the motor for EPS concerning Example 1. FIG. 1 is a front view of an EPS motor according to Embodiment 1. FIG. FIG. 4 is an enlarged front view showing a part of the EPS motor shown in FIG. 3. It is sectional drawing which shows the motor case of the motor for EPS shown in FIG. It is sectional drawing which expands and shows a part of motor for EPS shown in FIG. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning other embodiment of this invention. It is sectional drawing which expands and shows a part of EPS motor concerning other embodiment of this invention. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning Example 2 of this invention. FIG. 10 is an enlarged sectional view showing a part of the EPS motor shown in FIG. 9. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning other embodiment of this invention. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning the reference example of this invention.

It is sectional drawing along the rotating shaft direction of the motor for EPS concerning Example 1 of this invention. It is a bottom view of the motor for EPS concerning Example 1. FIG. 1 is a front view of an EPS motor according to Embodiment 1. FIG. FIG. 4 is an enlarged front view showing a part of the EPS motor shown in FIG. 3. It is sectional drawing which shows the motor case of the motor for EPS shown in FIG. It is sectional drawing which expands and shows a part of motor for EPS shown in FIG. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning other embodiment of this invention. It is sectional drawing which expands and shows a part of EPS motor concerning other embodiment of this invention. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning Example 2 of this invention. FIG. 10 is an enlarged sectional view showing a part of the EPS motor shown in FIG. 9. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning other embodiment of this invention. It is sectional drawing along the rotating shaft direction of the motor for EPS concerning other embodiment of this invention.

  Next, a rotating electrical machine according to a preferred embodiment of the present invention will be described with reference to the drawings. In the embodiments described below, an EPS (Electric Power Steering) motor will be described as an example of a rotating electrical machine. Moreover, the Example described below is the illustration for demonstrating this invention, and this invention is not limited only to these Examples. Therefore, the present invention can be implemented in various forms without departing from the gist thereof.

  1 is a cross-sectional view of the EPS motor according to the first embodiment of the present invention along the rotational axis direction, FIG. 2 is a bottom view of the EPS motor according to the first embodiment, and FIG. 3 is according to the first embodiment. FIG. 4 is an enlarged front view showing a part of the EPS motor shown in FIG. 3, FIG. 5 is a sectional view showing a motor case of the EPS motor shown in FIG. FIG. 2 is an enlarged cross-sectional view of a part of the EPS motor shown in FIG. 1. In the drawings, for easy understanding, the thickness, size, enlargement / reduction ratio, etc. of each member are not matched with the actual ones.

  As shown in FIGS. 1 to 6, the EPS motor 1 according to the first embodiment includes a motor case 10 formed in a substantially cylindrical shape, and a rotor 20 disposed in a substantially central portion inside the motor case 10. The stator 30 is inserted from the insertion port 11 (see FIG. 5) of the motor case 10 and disposed between the inner peripheral surface 12 of the motor case 10 and the outer peripheral surface of the rotor 20, and the insertion port 11 of the motor case 10. The bracket 50 is provided on the side, and fixes the EPS motor 1 to an EPS main body (not shown).

  Formed on the bottom surface 13 of the motor case 10 is a bearing housing portion 14 that houses a bearing (bearing) 22 that supports one end of a shaft (rotating shaft) 21 of the rotor 20. A flange 15 directed outward is formed on the end surface of the motor case 10 on the insertion port 11 side. The flange 15 causes the inner peripheral surface 12 of the motor case 10 to have a step (inner peripheral step) in which the inner diameter R (see FIG. 5) of the insertion port 11 is larger than the inner diameter r (see FIG. 5) on the bottom surface 13 side. Is formed. The surface on the insertion port 11 side of the flange 15 is an inner peripheral step surface 16 that comes into contact with an outer peripheral step surface 36 of the large diameter portion 34 of the stator 30 described in detail later. In the first embodiment, the diameter of the flange 15 is the inner diameter R of the motor case 10.

  The rotor 20 includes a shaft 21 rotatably disposed in the motor case 10, an annular rotor core 24 fixed to the outer peripheral surface of the shaft 21, a magnet 26 fixed to the outer peripheral surface of the rotor core 24, and a magnet 26 And an annular rotor cover 28 that covers the magnet 26 and is mounted on the outer peripheral surface of the motor.

  The shaft 21 for transmitting torque is rotatably supported at one end in the axial direction (end on the bottom surface 13 side) by a bearing 22 attached to the bearing housing portion 14 of the motor case 10. Further, the other axial end of the shaft 21 is rotatably supported by a bearing 52 attached to the bracket 50. A resolver rotor 53 is disposed between the bearing 52 and the rotor core 24 of the shaft 21, and a resolver stator 54 is disposed in the vicinity of the resolver rotor 53. The resolver stator 54 is fixed to a terminal block 55, and a power harness 57 inserted into a grommet 56 attached to the bracket 50 is connected to the terminal block 55. In addition, the code | symbol 58 described in FIG.2 and FIG.3 is a sensor harness.

  The stator 30 includes a stator core 31, an insulator 32 disposed on the stator core 31, and a coil 33 wound around the stator core 31 on which the insulator 32 is disposed. Then, when the coil 33 is energized via the power harness 57, a rotating magnetic field for rotationally driving the rotor 20 is formed. The coil 33 is joined to the terminal block 55 by TIG welding or the like.

  The stator 30 has a large-diameter portion 34 at the distal end located on the insertion port 11 side, and a bottom-diameter portion 35 that is smaller in outer diameter than the large-diameter portion 34 on the bottom surface 13 side. ing. That is, the stator 30 has a step (outer peripheral step) formed by the large-diameter portion 34 and the small-diameter portion 35, and this outer peripheral step is opposed to the inner peripheral step formed in the motor case 10. It has a complementary shape. The surface on the bottom surface 13 side of the large diameter portion 34 is an outer peripheral step surface 36 that contacts the inner peripheral step surface 16 of the motor case 10. Further, the outer diameter of the small diameter portion 35 of the stator 30 is smaller than the inner diameter of the small diameter portion of the motor case 10 (that is, a region facing the small diameter portion 35). As a result, a gap is formed between the outer peripheral surface of the small-diameter portion 35 of the stator 30 and the surface of the inner peripheral surface 12 of the motor case 10 that faces the small-diameter portion 35, and both are not in contact (not in direct contact). Structure). Therefore, when the stator 30 is inserted into the motor case 10, no stress is applied to the stator 30, it is possible to prevent the stator core 31 from being distorted, and it is possible to reduce the cause of loss torque and loss torque fluctuation. .

  The stator 30 is inserted from the insertion port 11 of the motor case 10 toward the back side (bottom surface 13 side) of the motor case 10, and the outer circumferential step surface 36 of the large diameter portion 34 is replaced with the inner circumferential step surface 16 of the motor case 10. The motor case 10 is disposed in contact with the motor case 10. Therefore, the stator 30 can be reliably positioned with respect to the motor case 10 in the axial direction.

  Furthermore, a bracket 50 is disposed on the surface of the large-diameter portion 34 opposite to the outer peripheral step surface 36, and the large-diameter portion 34 is sandwiched between the flange 15 of the motor case and the bracket 50. These are fastened together with screws 60. A long hole 38 into which the screw 60 is inserted is formed at a desired position of the large-diameter portion 34 of the stator 30. As shown in FIGS. 3 and 4, the elongated hole 38 has a shape extending (elongating) along the circumferential direction of the large diameter portion 34. Therefore, at the time of assembly, the stator 30 can be moved (rotated) to some extent in the circumferential direction, and the resolver signal and the induced voltage can be easily adjusted.

  In the EPS motor 1 according to the first embodiment, for example, as shown in FIG. 7, an annular groove 61 is formed along the outer peripheral surface of the end portion on the bottom surface 13 side of the stator core 31, and an elastic member is formed in the annular groove 61. 62 (for example, a damping steel plate, a C ring, an O ring, a resin ring, a rubber ring, etc.) is disposed between the outer peripheral surface of the stator 30 and the inner peripheral surface 12 of the motor case 10 so as to be an elastic member. 62 may be interposed. By doing so, it is possible to prevent the stator 30 from vibrating when vibration is applied, and to insert and position the stator 30 with respect to the motor case 10 more easily. At this time, the arrangement position of the elastic member 62 is not particularly limited as long as it is between the small diameter portion 35 and the inner peripheral surface 12 of the motor case 10, but for the EPS according to the first embodiment. Since the motor 1 has a configuration in which the large-diameter portion 34 is sandwiched between the flange and the bracket 50 and this portion is fixed, the elastic member 62 may be disposed at the end of the stator core 31 on the bottom surface 13 side. From the viewpoint of preventing vibration.

  In the EPS motor 1 according to the first embodiment, for example, as shown in FIG. 8, an elastic member 63 is disposed between the flange 15 of the motor case 10 and the large-diameter portion 34 of the stator 30. The elastic member 64 may be disposed between the large-diameter portion 34 of the 30 and the bracket 50. By doing so, it is possible to prevent the excitation force generated in the circumferential direction of the stator core 31 from being transmitted to the motor case 10 during energization, and further reduce noise and vibration generated from the EPS motor 1. be able to. Further, the centering of the stator 30 can be facilitated, and the sealing performance can be improved. In addition, an effect can be acquired only by arrange | positioning any one among the elastic members 63 and 64. FIG.

  Next, an EPS motor according to a second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, the same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 9 is a cross-sectional view taken along the rotational axis direction of the EPS motor according to the second embodiment of the present invention, and FIG. 10 is an enlarged cross-sectional view of a part of the EPS motor shown in FIG. In the drawings, for easy understanding, the thickness, size, enlargement / reduction ratio, etc. of each member are not matched with the actual ones.

  As shown in FIGS. 9 and 10, the EPS motor 2 according to the second embodiment differs from the EPS motor 1 according to the first embodiment in that the structure of the motor case 100, the structure of the stator 130, This is a mounting structure of the stator 130.

  The motor case 100 is formed in a substantially cylindrical shape, and a flange 115 facing outward is formed on the end surface on the insertion port 11 side. Further, on the inner peripheral surface 112 of the motor case 100, a step (inner peripheral step) in which the inner diameter R (see FIG. 9) on the insertion port 11 side is larger than the inner diameter r (see FIG. 9) on the back side (bottom surface 13 side). ) Is formed. The inner circumferential step surface 116 is formed on the inner circumferential surface 112 of the motor case 100 by the inner circumferential step.

  The stator 130 includes a stator core 131, an insulator 32 provided on the stator core 131, and a coil 33 wound around the stator core 131 provided with the insulator 32. On the outer peripheral surface 132 of the stator core 131, a step (outer peripheral step) having a shape complementary to the inner peripheral step is formed at a position facing the inner peripheral step formed in the motor case 100. In other words, the stator 130 has a large-diameter portion 134 that is located on the insertion port 11 side from the substantially central portion in the axial direction, and the bottom surface 13 side is smaller than the large-diameter portion 134 and the outer diameter is smaller than the large-diameter portion 134. A small-diameter portion 135 is formed. The outer peripheral step surface 136 is formed on the outer peripheral surface 132 of the stator core 131 so as to abut on the inner peripheral step surface 116.

  Further, the outer diameter of the small-diameter portion 135 of the stator 130 is smaller than the inner diameter of the small-diameter portion of the motor case 100 (that is, the region facing the small-diameter portion 135), and the outer diameter of the large-diameter portion 134 of the stator 130 is The inner diameter of the large-diameter portion of the motor case 100 (that is, the region facing the large-diameter portion 134) is smaller. With this configuration, a gap is formed between the outer peripheral surface of the small-diameter portion 135 of the stator 130 and the surface of the inner peripheral surface 112 of the motor case 100 facing the small-diameter portion 135. Structure). In addition, a gap is formed between the outer peripheral surface of the large-diameter portion 134 of the stator 130 and the surface of the inner peripheral surface 112 of the motor case 100 that faces the large-diameter portion 134, and the two are not in contact (direct contact). Structure). Therefore, when the stator 130 is inserted into the motor case 100, no stress is applied to the stator 130, distortion of the stator core 131 can be prevented, and loss torque and loss torque fluctuation factors can be reduced. .

  In addition, a gap formed between the outer peripheral surface of the large diameter portion 134 of the stator 130 and the surface of the inner peripheral surface 112 of the motor case 100 facing the large diameter portion 134 is filled with the adhesive 110. The large diameter portion 134 and the motor case 100 are fixed by the adhesive 110. Note that the adhesive 110 can be arbitrarily selected from various materials such as an epoxy-based material, an anaerobic adhesive, and a material containing a foam.

  The stator 130 is inserted from the insertion port 11 of the motor case 100 toward the back side (bottom surface 13 side) of the motor case 100, and the outer circumferential step surface 136 of the large diameter portion 134 is replaced with the inner circumferential step surface 116 of the motor case 100. The motor case 100 is disposed in contact with the motor case 100. Therefore, the stator 130 can be reliably positioned with respect to the motor case 100 in the axial direction. Further, since the adhesive 110 is interposed closer to the insertion opening 11 than the inner circumferential stepped surface 116, the adhesive 110 is temporarily placed on the back side (the bottom surface 13 side) when the stator 130 is inserted into the motor case 100. ), It is possible to prevent the adhesive 110 from moving further back by the contact between the inner circumferential step surface 116 and the outer circumferential step surface 136. Therefore, it is possible to prevent the presence of foreign matter due to the adhesive 110 on the back side of the EPS motor 2.

  The adhesive 110 may be applied to the large diameter portion 134 of the stator 130 or may be applied to the surface of the inner peripheral surface 112 of the motor case 100 that faces the large diameter portion 134. The adhesive 110 may be applied in advance at a predetermined position. After the stator 130 is inserted into the motor case 100, the large diameter portion 134 and the surface of the motor case 100 facing the large diameter portion 134 are arranged. It may be filled in between.

  A bracket 50 is disposed on the flange 15 of the motor case 100 where the stator 130 is disposed. The bracket 50 is fixed to one end of the resolver holder 139 with a screw 70.

Further, the EPS motor 2 according to the reference example of the present invention forms an inner circumferential step so that the end surface on the bottom surface 13 side of the stator 130 contacts the inner circumferential step surface 116 as shown in FIG. May be. In other words, in the case of this configuration, the end surface on the bottom surface 13 side of the stator 130 becomes a contact surface that contacts the inner circumferential step surface 116.

  In the EPS motor 2 according to the second embodiment, for example, as shown in FIG. 12, the inner peripheral step is formed so that the end surface on the bottom surface 13 side of the stator 130 contacts the inner peripheral step surface 116. Good. In other words, in the case of this configuration, the end surface on the bottom surface 13 side of the stator 130 becomes a contact surface that contacts the inner circumferential step surface 116.

  In the second embodiment, the inner peripheral step formed by the flange 115 and the inner peripheral step forming the inner peripheral step surface 116 are described. However, the present invention is not limited to this. For example, a motor case 100 may have a configuration in which only the inner peripheral step forming the inner peripheral step surface 116 is formed without forming the flange 115, and three or more inner peripheral steps may be formed in the motor case 100. Further, it is only necessary to form an outer peripheral step in the stator 130 that faces the inner peripheral step formed in the motor case 100.

  1, 2 ... EPS motor, 10, 100 ... motor case, 11 ... insertion port, 16, 116 ... inner peripheral step surface, 20 ... rotor, 30, 130 ... stator, 31, 131 ... stator core, 34, 134 ... large Diameter part, 35, 135 ... Small diameter part, 36, 136 ... Outer peripheral step surface, 50 ... Bracket, 62, 63, 64, 162, 164 ... Elastic member, 110 ... Adhesive

Claims (3)

A rotating electrical machine comprising: a motor case formed in a substantially cylindrical shape; and a stator that is inserted from an insertion port of the motor case and disposed inside the motor case,
The inner peripheral surface of the motor case is formed with an inner peripheral step that has an inner diameter on the insertion port side larger than the inner diameter on the inner side, and the motor case has an inner peripheral step surface formed by the inner peripheral step. Have
The stator has a contact surface that contacts the inner peripheral step surface,
The inner peripheral surface of the motor case is not in contact with the outer peripheral surface of the stator, and the stator has an outer peripheral step that is complementary to the inner peripheral step at a position facing the inner peripheral step of the outer peripheral surface of the stator. The contact surface is formed of an outer peripheral step surface formed by the outer peripheral step, and the inner peripheral step surface and the outer peripheral step surface are in contact with each other,
Of between the outer peripheral surface of the inner circumferential surface of the motor case stator, only the insertion port side of the inner stepped surface, Ri Na by interposing an adhesive,
A rotating electrical machine in which a ring member is interposed between an inner peripheral surface of a small diameter portion formed by the inner peripheral step of the motor case and an outer peripheral surface of a small diameter portion formed by the outer peripheral step of the stator . Electric rotating machine according to claim 1, wherein said ring member is made of an elastic member. The rotating electrical machine according to claim 1 or 2 , wherein the rotating electrical machine is disposed in an electric power steering device.

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