JP2017198304A - clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the remarkable lowering of a magnetic suction force between a rotor and an armature when reducing a clutch in size.SOLUTION: A clutch comprises a rotor 10 and an armature 20. A first slit 13c as an external peripheral side magnetism block part, and a third slit 13d as an internal peripheral side magnetism block part arranged at a rotation center side rather than the first slit 13c are formed at a contact face 13a of the rotor 10. A second slit 20c as an armature side magnetism block part arranged at a rotation center side rather than the first slit 13c is formed at a contact face 20a of the armature 20. Furthermore, a friction material 41 having a circular disc shape, and continuing over the whole area in a circumferential direction is arranged at the contact face 20a of the armature 20. The friction material 41 is arranged in a position which is overlapped on the second slit 20c in an axial line direction of a rotation center line O.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a clutch.

  In the dry single-plate electromagnetic clutch, when the armature is attracted to the rotor by magnetic force, the contact surface of the rotor and the contact surface of the armature come into contact with each other. The transmission torque of the electromagnetic clutch is represented by the product of the coefficient of friction between the contact surface of the rotor and the contact surface of the armature, the magnetic attraction force between the rotor and the armature, and the effective friction radius. For this reason, in the conventional clutch, a friction material is disposed on the contact surface of the rotor in order to increase the friction coefficient of the entire contact surface and improve the transmission torque (see, for example, Patent Document 1). The friction material is made of a material having a higher friction coefficient with the contact surface of the armature than the magnetic material portion of the contact surface of the rotor made of a magnetic material. The friction material is made of a nonmagnetic material and has an annular shape.

  Here, in order to effectively improve the transmission torque, it is desirable to increase the effective friction radius of the friction material as much as possible. Furthermore, it is desirable to suppress the deterioration of magnetic efficiency as much as possible by reducing the area of the magnetic material portion that is a path of magnetic flux on the contact surface by the friction material that is a nonmagnetic material.

  For this reason, in the conventional clutch, a position that overlaps with the outermost magnetic shield portion of the plurality of magnetic shield portions formed on the contact surface of the rotor in the axial direction of the rotation center line of the rotor Had been placed in. The plurality of magnetic blockers are for forming a magnetic circuit between the rotor and the armature. The plurality of magnetic shielding portions are formed concentrically around the rotation center line. In other words, the plurality of magnetic shielding portions have an annular shape centered on the rotation center line and have different radii. The band width of the friction material, that is, the width in the radial direction of the friction material is larger than the width in the radial direction of the magnetic shielding portion on the outer peripheral side. For this reason, the area of the magnetic material part in the contact surface of a rotor is reducing by installation of a friction material compared with the case where a friction material is not installed.

JP 2014-159873 A

  By the way, in the electromagnetic clutch mounted in a vehicle, the need for the weight reduction of an electromagnetic clutch, ie, size reduction, is increasing with the recent fuel efficiency regulation. Here, the miniaturization of the electromagnetic clutch means a reduction in the diameter of the electromagnetic clutch.

  However, when the electromagnetic clutch is reduced in size, the area of the contact surface of the rotor and the contact surface of the armature is reduced as compared with that before the size reduction. For example, if the outer diameter is changed smaller without changing the inner diameter of the contact surface of the rotor, the area of the contact surface of the rotor is reduced. For this reason, the area of the magnetic material portion on the contact surface of the rotor is reduced. When the area of the magnetic material portion is reduced, the magnetic efficiency is deteriorated, and the magnetic attractive force between the rotor and the armature is reduced.

  At this time, similarly to the above-described conventional electromagnetic clutch, an annular friction material made of a non-magnetic material is placed at a position overlapping with the magnetic shielding portion on the outer peripheral side of the contact surface of the rotor in the axial direction. It is possible to arrange. The width dimension in the radial direction of the friction material is larger than the width dimension in the radial direction of the magnetic shielding portion. In this case, the area of the magnetic material portion on the contact surface of the rotor is further reduced. As a result, the miniaturized electromagnetic clutch has a problem that the magnetic attractive force is greatly reduced and a desired transmission torque cannot be obtained as compared with the conventional electromagnetic clutch before miniaturization.

  In order to suppress the reduction of the area of the magnetic material part due to the installation of the friction material, it is considered to reduce the width of the annular friction material in the radial direction while keeping the same location as the conventional electromagnetic clutch. It is done. The radial width of the friction material is the distance in the radial direction between the inner peripheral side end and the outer peripheral side end of the friction material. However, when the width of the friction material in the radial direction is reduced, the strength of the friction material is reduced, and there is a possibility that the friction material may be cracked when the friction material is transported or assembled during manufacture of the electromagnetic clutch. For this reason, it is not preferable to simply reduce the width of the annular friction material in the radial direction.

  An object of this invention is to provide the clutch which can suppress the significant fall of the magnetic attraction force between a rotor and an armature at the time of reducing a clutch in size.

In order to achieve the above object, the clutch according to the first aspect of the present invention provides:
A rotor (10) made of a magnetic material, which receives a rotational driving force from a driving source and rotates around a rotation center line (O);
An armature (20) that is made of a magnetic material and is attracted to the rotor by a magnetic force to transmit a rotational driving force;
Each of the rotor and the armature has a contact surface (13a, 20a) that comes into contact with the other side when the armature is attracted to the rotor,
The contact surface (13a) of the rotor has a shape along the circumferential direction centering on the rotation center line, and rotates more than the outer peripheral side magnetic blocker (13c) that blocks the magnetic flux flow and the outer peripheral side magnetic blocker. It is arranged on the center side and has a shape along the circumferential direction centering on the rotation center line, and is formed with inner circumferential side magnetic shielding portions (13d, 13e) that block the magnetic flux flow,
The armature contact surface (20a) is disposed closer to the center of rotation than the outer periphery side magnetic shield, and has a shape along the circumferential direction centering on the rotation center line, and interrupts the magnetic flux flow. Part (20c, 20d) is formed,
Furthermore, the contact surface of the armature is provided with a friction material (41, 45) made of a non-magnetic material in an annular shape continuous over the entire circumferential direction,
The friction material is disposed at a position overlapping the armature-side magnetic shielding portion in the axial direction of the rotation center line.

  In the present invention, the friction material is arranged at a position overlapping in the axial direction with respect to the armature-side magnetic shielding portion arranged closer to the rotation center than the outer peripheral-side magnetic shielding portion. Thereby, compared with the case where the friction material is arrange | positioned in the position which overlaps with an outer peripheral side magnetic interruption | blocking part in an axial direction, the outer diameter of a friction material can be made small and the area of a friction material can be made small. For this reason, the contact area between the magnetic material portion of the contact surface of the rotor and the magnetic material portion of the contact surface of the armature can be increased, and the magnetic attractive force between the rotor and the armature can be increased.

  Therefore, according to the present invention, compared with the case where the friction material is arranged at the position overlapping the outer peripheral side magnetic shielding portion in the axial direction, the gap between the rotor and the armature when the electromagnetic clutch is reduced in size. A significant decrease in the magnetic attractive force can be suppressed.

The clutch according to the invention of claim 2 is
A rotor (10) made of a magnetic material, which receives a rotational driving force from a driving source and rotates around a rotation center line (O);
An armature (20) that is made of a magnetic material and is attracted to the rotor by a magnetic force to transmit a rotational driving force;
Each of the rotor and the armature has a contact surface (13a, 20a) that comes into contact with the other side when the armature is attracted to the rotor,
The contact surface (13a) of the rotor has a shape along the circumferential direction centering on the rotation center line, and rotates more than the outer peripheral side magnetic blocker (13c) that blocks the magnetic flux flow and the outer peripheral side magnetic blocker. It is arranged on the center side and has a shape along the circumferential direction centering on the rotation center line, and is formed with inner circumferential side magnetic shielding portions (13d, 13e) that block the magnetic flux flow,
The armature contact surface (20a) is disposed closer to the center of rotation than the outer periphery side magnetic shield, and has a shape along the circumferential direction centering on the rotation center line, and interrupts the magnetic flux flow. Part (20c, 20d) is formed,
Furthermore, the contact surface of the rotor is provided with a friction material (43, 47) made of a non-magnetic material, which is an annular shape continuous over the entire circumferential direction,
The friction material is disposed at a position overlapping the inner circumferential side magnetic shielding portion in the axial direction of the rotation center line.

  In the present invention, the friction material is disposed at a position overlapping in the axial direction with respect to the inner circumferential side magnetic shielding portion disposed closer to the rotation center than the outer circumferential side magnetic shielding portion. Thereby, compared with the case where the friction material is arrange | positioned in the position which overlaps with an outer peripheral side magnetic interruption | blocking part in an axial direction, the outer diameter of a friction material can be made small and the area of a friction material can be made small. For this reason, the contact area between the magnetic material portion of the contact surface of the rotor and the magnetic material portion of the contact surface of the armature can be increased, and the magnetic attractive force between the rotor and the armature can be increased.

  Therefore, according to the present invention, compared with the case where the friction material is arranged at the position overlapping the outer peripheral side magnetic shielding portion in the axial direction, the gap between the rotor and the armature when the electromagnetic clutch is reduced in size. A significant decrease in the magnetic attractive force can be suppressed.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a figure which shows the cross-sectional structure of the whole electromagnetic clutch in 1st Embodiment. It is a top view of the friction surface of the rotor in FIG. It is a top view of the friction surface of the armature in FIG. It is an enlarged view of the part in which the friction material is installed among the armatures in FIG. 6 is a plan view of a friction surface of a rotor of an electromagnetic clutch in Comparative Example 1. FIG. It is a figure which shows the cross-sectional structure of the whole electromagnetic clutch in 2nd Embodiment. It is a top view of the friction surface of the rotor in FIG. It is an enlarged view of the part in which the friction material is installed among the rotors in FIG. It is a top view of the friction surface of the rotor of the electromagnetic clutch in 3rd Embodiment. It is a top view of the friction surface of the armature of the electromagnetic clutch in 3rd Embodiment. It is a top view of the friction surface of the rotor of the electromagnetic clutch in 4th Embodiment. It is a top view of the friction surface of the armature of the electromagnetic clutch in 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
An electromagnetic clutch 1 according to the first embodiment shown in FIG. 1 is used for a drive mechanism of a compressor 2 that obtains a rotational drive force from an engine as a drive source that outputs a vehicle travel drive force and rotates the compression mechanism. Is. Therefore, in this embodiment, an engine is a drive source and the compressor 2 is a driven device.

  The compressor 2 sucks and compresses the refrigerant, and is decompressed by a radiator that dissipates the refrigerant discharged from the compressor 2, an expansion valve that decompresses and expands the refrigerant flowing out of the radiator, and an expansion valve. A refrigerating cycle device for a vehicle air conditioner is configured together with an evaporator that evaporates the refrigerant and exerts an endothermic effect.

  The electromagnetic clutch 1 includes a rotor 10 that constitutes a driving side rotating body that rotates around a rotation center line O when receiving a rotational driving force from an engine, and a driven side rotation that is coupled to a rotating shaft 2 a of the compressor 2. And an armature 20 constituting the body. By connecting or disconnecting the rotor 10 and the armature 20, the transmission of the rotational driving force (ie, torque) from the engine to the compressor 2 is interrupted. FIG. 1 shows a state where the rotor 10 and the armature 20 are separated from each other.

  That is, when the electromagnetic clutch 1 connects the rotor 10 and the armature 20, the rotational driving force of the engine is transmitted to the compressor 2 and the refrigeration cycle apparatus operates. On the other hand, when the electromagnetic clutch 1 disconnects the rotor 10 and the armature 20, the rotational driving force of the engine is not transmitted to the compressor 2, and the refrigeration cycle apparatus does not operate. The operation of the electromagnetic clutch 1 is controlled by a control signal output from an air conditioning control device that controls the operation of various components of the refrigeration cycle apparatus.

  Hereinafter, a specific configuration of the electromagnetic clutch 1 will be described. As shown in FIG. 1, the electromagnetic clutch 1 includes a rotor 10, an armature 20, and a stator 30.

  The rotor 10 has a double-cylindrical structure with a U-shaped cross section that is open on the side opposite to the armature 20 that is away from the armature 20. That is, the rotor 10 connects the outer cylindrical portion 11, the inner cylindrical portion 12 disposed on the inner peripheral side of the outer cylindrical portion 11, and the end portions on the armature 20 side of the outer cylindrical portion 11 and the inner cylindrical portion 12. Thus, it has the end surface part 13 which spreads in the direction orthogonal to the rotation center line O. The outer cylindrical portion 11, the inner cylindrical portion 12, and the end surface portion 13 are made of a steel material as a magnetic material.

  The outer cylindrical portion 11 and the inner cylindrical portion 12 are arranged coaxially with respect to the rotation shaft 2 a of the compressor 2. That is, the rotation center line O shown in FIG. 1 is a rotation center line of the outer cylindrical portion 11 and the inner cylindrical portion 12, and also a rotation center line of the rotation shaft 2a. A pulley portion 14 is joined to the outer peripheral side of the outer cylindrical portion 11. The pulley portion 14 is formed with a V groove 14a on which a V belt is hung. An outer race of the ball bearing 15 is fixed to the inner peripheral side of the inner cylindrical portion 12.

  The ball bearing 15 fixes the rotor 10 to the housing forming the outer shell of the compressor 2 so as to be rotatable. Therefore, the inner race of the ball bearing 15 is fixed to the housing boss portion 2 b provided in the housing of the compressor 2.

  The end surface portion 13 is a wall portion facing the armature 20. The end surface portion 13 has one surface 13a on the armature 20 side and another surface 13b on the non-armature side. In other words, the end surface portion 13 has one surface 13a and another surface 13b arranged on one side and the other side in the axial direction of the rotation center line O, respectively, and the one surface 13a and the other surface 13b are axes of the rotation center line O. Each extends in a direction orthogonal to the direction. One surface 13 a of the end surface portion 13 faces the armature 20, and when the armature 20 is connected to the rotor 10, it becomes a contact surface 13 a that contacts the counterpart armature 20. The contact surface 13a is also a friction surface that generates friction upon contact with the armature 20. Hereinafter, one surface 13a of the end surface portion 13 is referred to as a friction surface 13a. Hereinafter, the axial direction of the rotation center line O is simply referred to as an axial direction.

  The armature 20 is made of a steel material as a magnetic material. The armature 20 is a disk-shaped member that extends in a direction perpendicular to the rotation center line O and that has a through hole that penetrates the front and back in the axial direction at the center. The rotation center of the armature 20 is disposed coaxially with the rotation shaft 2 a of the compressor 2. That is, the rotation center line of the armature 20 coincides with the rotation center line O.

  The armature 20 has one surface 20a on the rotor 10 side and another surface 20b on the side opposite to the rotor. In other words, the armature 20 has one surface 20a and another surface 20b arranged on one side and the other side in the axial direction of the rotation center line O, respectively, and the one surface 20a and the other surface 20b are in a direction orthogonal to the axial direction. Each is extended. One surface 20 a of the armature 20 faces the rotor 10, and when the armature 20 is connected to the rotor 10, it becomes a contact surface 20 a that contacts the counterpart rotor 10. The contact surface 20a is also a friction surface that generates friction upon contact with the rotor 10. Hereinafter, one surface 20a of the armature 20 is referred to as a friction surface 20a.

  A substantially disc-shaped outer hub 21 is fixed to the other surface 20 b of the armature 20. The outer hub 21 constitutes a connecting member that connects the armature 20 and the rotating shaft 2a of the compressor 2 together with an inner hub 22 described later. The outer hub 21 and the inner hub 22 have cylindrical portions 21 a and 22 a that extend in the axial direction of the rotation center line O, respectively, and the inner peripheral surface of the cylindrical portion 21 a of the outer hub 21 and the cylindrical portion 22 a of the inner hub 22. Cylindrical rubber 23 is vulcanized and bonded to the outer peripheral surface. The rubber 23 is an elastic member made of an elastic material (that is, an elastomer).

  The inner hub 22 is fixed by being tightened by a bolt 24 in a screw hole provided in the rotary shaft 2 a of the compressor 2. That is, the inner hub 22 is configured to be connectable to the rotary shaft 2 a of the compressor 2.

  Thereby, the armature 20, the outer hub 21, the rubber 23, the inner hub 22, and the rotating shaft 2a of the compressor 2 are connected. When the rotor 10 and the armature 20 are connected, the armature 20, the outer hub 21, the rubber 23, the inner hub 22, and the rotation shaft 2 a of the compressor 2 rotate together with the rotor 10.

  The rubber 23 applies an elastic force to the outer hub 21 in a direction away from the rotor 10. Due to this elastic force, in a state where the rotor 10 and the armature 20 are separated, a predetermined gap is formed between the friction surface 20a of the armature 20 connected to the outer hub 21 and the friction surface 13a of the rotor 10. Is done.

  The stator 30 is disposed in the internal space of the rotor 10 surrounded by the outer cylindrical portion 11, the inner cylindrical portion 12 and the end surface portion 13 of the rotor 10. For this reason, the stator 30 faces the other surface 13 b of the end surface portion 13. The stator 30 is made of a steel material as a magnetic material, and houses an electromagnetic coil 35 therein.

  The stator 30 has a double cylindrical structure with a U-shaped cross section having an opening 30a on the end face 13 side. Specifically, the stator 30 includes an outer cylindrical portion 31, an inner cylindrical portion 32 disposed on the inner peripheral side of the outer cylindrical portion 11, and the friction surface 13a of the rotor 10 of the outer cylindrical portion 31 and the inner cylindrical portion 32. And an end surface portion 33 extending in a direction perpendicular to the rotation center line O so as to connect the end portions on the side away from the center.

  An annular coil spool 34 is accommodated in the internal space of the stator 30. The coil spool 34 is formed from a resin material such as polyamide resin. An electromagnetic coil 35 is wound on the coil spool 34.

  Further, a resin member 36 such as a polyamide resin for sealing the electromagnetic coil 35 is provided on the opening 30 a side of the stator 30. As a result, the opening 30 a of the stator 30 is blocked by the resin member 36.

  A stator plate 37 is fixed to the outside (right side in FIG. 1) of the end surface portion 33 of the stator 30. The stator 30 is fixed to the housing of the compressor 2 via the stator plate 37.

  As shown in FIG. 2, a plurality of first slits 13 c and a plurality of third slits 13 d are formed on the friction surface 13 a of the rotor 10. The plurality of first slits 13c constitutes a first magnetic shielding part for forming a magnetic circuit X described later. The plurality of third slits 13d are arranged on the radially inner side of the rotor 10 (that is, the rotation center side of the rotor 10) than the plurality of first slits 13c. The plurality of third slits 13d constitutes a third magnetic shielding part for forming a magnetic circuit X described later. The first magnetic interrupter and the third magnetic interrupter interrupt the magnetic flux flow in the radial direction of the friction surface 13 a of the rotor 10.

  One first slit 13c is formed in an arc shape. The plurality of first slits 13c are arranged in an annular shape in a discontinuous state. Therefore, the first magnetic shield is formed in a shape along the circumferential direction with the rotation center line O as the center. Similarly, one third slit 13d is formed in an arc shape. The plurality of third slits 13d are arranged in an annular shape in a discontinuous state. Therefore, the third magnetic shield is formed in a shape along the circumferential direction with the rotation center line O as the center. In this embodiment, the 1st slit 13c which comprises a 1st magnetic shielding part corresponds to an outer peripheral side magnetic shielding part, and the 3rd slit 13d which comprises a 3rd magnetic shielding part corresponds to an inner peripheral side magnetic shielding part. For this reason, in this embodiment, one inner peripheral side magnetic shielding part is formed.

  As shown in FIG. 1, one first slit 13 c passes through the end surface portion 13 in the axial direction. One first slit 13c is constituted by a first slit forming surface 13c1. One third slit 13d penetrates the end surface portion 13 in the axial direction. Similarly, one third slit 13d is constituted by a second slit forming surface 13d1.

  As shown in FIG. 3, a plurality of second slits 20 c are formed on the friction surface 20 a of the armature 20. The plurality of second slits 20c constitutes a second magnetic shielding part for forming a magnetic circuit X described later. The second magnetic blocker blocks the magnetic flow in the radial direction of the friction surface 20a of the armature 20. One second slit 20c is formed in an arc shape. The plurality of second slits 20c are annularly arranged in a discontinuous state in the circumferential direction. Therefore, the 2nd magnetic interruption | blocking part is formed in the shape in alignment with the circumferential direction. In this embodiment, the 2nd slit 20c which comprises a 2nd magnetic shielding part is equivalent to an armature side magnetic shielding part. For this reason, in this embodiment, one armature side magnetic shielding part is formed.

  As shown in FIG. 1, one second slit 20c penetrates the armature 20 in the axial direction. One second slit 20c is constituted by a slit forming surface 20c1. The plurality of second slits 20 c are arranged at positions between the plurality of first slits 13 c and the plurality of third slits 13 d in the radial direction of the rotor 10. Therefore, the first magnetic shielding part, the second magnetic shielding part, and the third magnetic shielding part are sequentially arranged from the outer side to the inner side in the radial direction of the rotor 10.

  As shown in FIG. 3, a friction material 41 is provided on the friction surface 20 a of the armature 20. The friction material 41 has an annular shape centering on the rotation center line O, and has a shape continuous over the entire circumferential direction. The friction material 41 is disposed in a portion of the friction surface 20a where a plurality of second slits 20c are formed. In other words, the friction material 41 is disposed at a position overlapping the plurality of second slits 20c in the axial direction on the friction surface 20a. The width dimension in the radial direction of the friction material 41 is larger than the width dimension in the radial direction of the second slit 20c. For this reason, the friction material 41 covers all of the plurality of second slits 20c.

  The friction material 41 is a member for increasing the friction coefficient of the friction surface 20 a of the armature 20 with respect to the friction surface 13 a of the rotor 10. The friction material 41 is made of a material having a higher friction coefficient with the friction surface 13a of the rotor 10 than the magnetic material portion of the friction surface 20a of the armature 20 made of a magnetic material. The friction material 41 is made of a nonmagnetic material. Examples of the material constituting the friction material 41 include a material obtained by solidifying alumina powder with a resin material, and a sintered material of metal powder such as aluminum.

  As shown in FIG. 4, the friction material 41 is held in a groove 42 as a holding portion provided on the friction surface 20 a of the armature 20. The groove 42 is formed at a position overlapping the second slit 20c in the axial direction. The width of the groove 42 in the radial direction of the armature 20 is larger than the width of the second slit 20c. The groove 42 has a bottom surface 42a and a side surface 42b. A second slit 20c is formed in a part of the bottom surface 42a, and the internal space of the groove 42 and the second slit 20c are connected. The friction material 41 is bonded to the bottom surface 42a of the groove 42 through an adhesive.

  Next, the operation of the electromagnetic clutch 1 having the above configuration will be described. When the electromagnetic coil 35 is energized, a magnetic flux flows from the stator 30 to the magnetic circuit X that returns to the stator 30 through the rotor 10 and the armature 20 as indicated by a one-dot chain line in FIG. At this time, the magnetic flux meanders and flows between the end face portion 13 of the rotor 10 and the armature 20 by the first, second, and third magnetic blockers. Thereby, a magnetic force is generated between the rotor 10 and the armature 20. Therefore, when the electromagnetic coil 35 is energized, the armature 20 is attracted to the friction surface 13a of the rotor 10 by the magnetic force generated by the electromagnetic coil 35, and the rotor 10 and the armature 20 are connected. Thereby, the rotational driving force from the engine is transmitted to the compressor 2.

  On the other hand, when the energization of the electromagnetic coil 35 is interrupted, that is, when the electromagnetic coil 35 is not energized, the above-described magnetic force is not generated, and the armature 20 is separated from the friction surface 13a of the rotor 10 by the elastic force of the rubber 23. It is. Thereby, the rotational driving force from the engine is not transmitted to the compressor 2.

  Next, the effect which the electromagnetic clutch 1 of this embodiment has is demonstrated.

  First, the electromagnetic clutch 1 of this embodiment and the electromagnetic clutch J1 of the comparative example 1 shown in FIG. 5 are compared. In the electromagnetic clutch J1 of Comparative Example 1, the annular friction material 40 is disposed at a position where it overlaps with the first slits 13c of the friction surface 13a of the rotor 10 in the axial direction. The width L0 in the radial direction of the friction material 40 in the comparative example 1 is larger than the width L1 in the radial direction of the friction material 41 in the present embodiment. Other configurations are the same as those of the present embodiment. For example, the outer diameter and inner diameter of the friction surface 13a of the rotor 10 in Comparative Example 1 and the outer diameter and inner diameter of the friction surface 20a of the armature 20 are the same as in this embodiment. That is, the contact area between the entire contact surface of the rotor 10 and the entire contact surface of the armature 20 in Comparative Example 1 is the same as that of the present embodiment.

  On the other hand, in the electromagnetic clutch 1 of the present embodiment, the friction material 41 is disposed at a position overlapping the second slit 20c disposed on the rotational center side of the friction surface 20a of the armature 20 with respect to the first slit 13c. ing. For this reason, the friction material 41 of this embodiment has a smaller diameter (that is, the outer diameter) than the friction material 40 of Comparative Example 1. In an annular friction material, when compared with the same width dimension in the radial direction of the friction material, the smaller the friction material diameter, the smaller the friction material area. Therefore, the friction material 41 of this embodiment has a smaller area than the friction material 40 of Comparative Example 1.

  Therefore, according to the electromagnetic clutch 1 of the present embodiment, the contact between the magnetic material portion of the friction surface 13a of the rotor 10 and the magnetic material portion of the friction surface 20a of the armature 20 as compared with the electromagnetic clutch J1 of Comparative Example 1. The area can be increased. The larger the contact area, the greater the magnetic attractive force between the rotor 10 and the armature 20. Therefore, according to the electromagnetic clutch 1 of this embodiment, compared with the electromagnetic clutch J1 of the comparative example 1, magnetic attraction force can be enlarged.

  Here, as described in the problem to be solved by the invention, when the electromagnetic clutch is reduced in size, the magnetic material portion on the friction surface 13a of the rotor 10 and the magnetism of the friction surface 20a of the armature 20 are smaller than before the size reduction. The contact area of the material part is reduced. At this time, when the friction material is disposed as in the electromagnetic clutch J1 of Comparative Example 1, the contact area is further reduced. As a result, the miniaturized electromagnetic clutch has a problem that the magnetic attractive force is greatly reduced and a desired transmission torque cannot be obtained as compared with the electromagnetic clutch before miniaturization. Since the conventional electromagnetic clutch is not designed for the purpose of downsizing, the contact area between the friction surface 13a of the rotor 10 and the friction surface 20a of the armature 20 is sufficiently large. For this reason, even if the area of the friction material is large, the contact area between the magnetic material portions is sufficiently ensured, and the necessary magnetic attractive force is obtained. However, if the outer diameter of each of the rotor 10 and the armature 20 is changed to be small in order to reduce the size of the electromagnetic clutch, the contact area between the magnetic material portions decreases. For this reason, in order to obtain a required magnetic attraction force, it is necessary to secure a contact area between the magnetic material portions.

  On the other hand, according to the electromagnetic clutch 1 of this embodiment, compared with the electromagnetic clutch J1 of the comparative example 1, it can suppress the reduction of the contact area of the magnetic material parts by installation of a friction material. For this reason, when the electromagnetic clutch is downsized, it is possible to suppress a significant decrease in the magnetic attractive force between the rotor 10 and the armature 20.

  Further, the friction material 41 of this embodiment has a smaller diameter than the friction material 40 of Comparative Example 1. The smaller the diameter of the annular member, the higher the rigidity. For this reason, the width L1 in the radial direction of the friction material 41 can be reduced while providing the friction material 41 with a necessary strength. For example, the width L1 in the radial direction of the friction material 41 can be made smaller than the width L0 in the radial direction of the friction material 40 in Comparative Example 1 while maintaining the same strength as that of the friction material 40 in Comparative Example 1. Thereby, the reduction | decrease of the contact area of the magnetic material parts by installation of a friction material can be suppressed more.

(Second Embodiment)
This embodiment differs from the first embodiment in the location of the friction material, and the other configuration of the electromagnetic clutch 1 is the same as that of the first embodiment.

  As shown in FIGS. 6 and 7, in the present embodiment, the friction material 43 is disposed in a portion of the friction surface 13 a of the rotor 10 where the plurality of third slits 13 d are formed. In other words, the friction material 43 is disposed on the friction surface 13a at a position overlapping the plurality of third slits 13d in the axial direction. The material and shape of the friction material 43 are the same as those of the friction material 41 of the first embodiment.

  As shown in FIG. 8, the friction material 43 is held in a groove 44 as a holding portion provided on the friction surface 13 a of the rotor 10. The groove 44 is formed at a position overlapping the third slit 13d in the axial direction. The width of the groove 44 in the radial direction of the rotor 10 is larger than the width of the third slit 13d. The groove 44 has a bottom surface 44a and a side surface 44b. A third slit 13d is formed in a part of the bottom surface 44a, and the internal space of the groove 44 and the third slit 13d are connected. The friction material 43 is bonded to the bottom surface 44a of the groove 44 through an adhesive.

  In the electromagnetic clutch 1 in the present embodiment, the friction material 43 is disposed at a position overlapping the third slit 13d disposed on the rotation center side of the plurality of first slits 13c in the friction surface 13a. For this reason, the friction material 43 of this embodiment has a smaller diameter and a smaller area than the friction material 40 of Comparative Example 1. Therefore, also in this embodiment, the same effect as the first embodiment can be obtained. In addition, since the diameter of a friction material can be made smaller than the 1st embodiment and the area of a friction material can be made smaller than this Embodiment, the higher effect than 1st Embodiment is acquired.

(Third embodiment)
The present embodiment is different from the first embodiment in the number of magnetic blocking portions and the location of the friction material. Other configurations of the electromagnetic clutch 1 are the same as those in the first embodiment.

  As shown in FIG. 9, a plurality of fifth slits 13e are formed on the friction surface 13a of the rotor 10 in addition to the plurality of first slits 13c and the plurality of third slits 13d. The plurality of fifth slits 13e are arranged on the radially inner side of the rotor 10 (that is, the rotation center side of the rotor 10) than the plurality of third slits 13d. The plurality of fifth slits 13e constitutes a fifth magnetic shielding part for forming a magnetic circuit. One fifth slit 13e is formed in an arc shape. The plurality of fifth slits 13e are arranged in an annular shape in a discontinuous state. Therefore, the fifth magnetic shielding part is formed along the circumferential direction. In the present embodiment, the third slit 13d constituting the third magnetic shielding part and the fifth slit 13e constituting the fifth magnetic shielding part correspond to the inner peripheral side magnetic shielding part. For this reason, in this embodiment, two inner peripheral side magnetic shielding parts are formed.

  As shown in FIG. 10, a plurality of fourth slits 20d are formed on the friction surface 20a of the armature 20 in addition to the plurality of second slits 20c. The plurality of fourth slits 20d are arranged on the radially inner side of the armature 20 (that is, the rotation center side of the armature 20) than the plurality of second slits 20c. The plurality of fourth slits 20d constitutes a fourth magnetic cutoff part for forming a magnetic circuit. In the present embodiment, the second slit 20c constituting the second magnetic shielding part and the fourth slit 20d constituting the fourth magnetic shielding part correspond to the armature-side magnetic shielding part. For this reason, in this embodiment, two armature-side magnetic shields are formed.

  The plurality of fourth slits 20 d are arranged at positions between the plurality of third slits 13 d and the plurality of fifth slits 13 e in the radial direction of the rotor 10. Therefore, in this embodiment, from the outer side in the radial direction of the rotor 10 toward the inner side, the first magnetic blocking unit, the second magnetic blocking unit, the third magnetic blocking unit, the fourth magnetic blocking unit, and the fifth magnetic blocking unit. Are arranged in order.

  Then, as shown in FIG. 10, the friction material 45 is located at a position overlapping the plurality of fourth slits 20 d arranged on the rotation center side of the plurality of first slits 13 c in the friction surface 20 a of the armature 20 in the axial direction. Has been placed. The material and shape of the friction material 45 are the same as those of the friction material 41 of the first embodiment. For this reason, the friction material 45 of this embodiment has a smaller diameter and a smaller area than the friction material 40 of Comparative Example 1. Therefore, also in this embodiment, the same effect as the first embodiment can be obtained. In addition, since the diameter of a friction material can be made smaller than this Embodiment and the area of a friction material can be made smaller than 2nd Embodiment, the higher effect than 2nd Embodiment is acquired.

(Fourth embodiment)
This embodiment is different from the third embodiment in the place where the friction material is installed. Other configurations of the electromagnetic clutch 1 are the same as those of the third embodiment.

  As shown in FIG. 11, a plurality of first slits 13c, a plurality of third slits 13d, and a plurality of fifth slits 13e are formed on the friction surface 13a of the rotor 10 as in the third embodiment. ing. As shown in FIG. 12, a plurality of second slits 20c and a plurality of fourth slits 20d are formed on the friction surface 20a of the armature 20 as in the third embodiment.

  In the present embodiment, as shown in FIG. 11, the friction surface 13 a of the rotor 10 is overlapped in the axial direction with the plurality of fifth slits 13 e arranged closer to the rotation center than the plurality of first slits 13 c. The friction material 47 is arranged. The material and shape of the friction material 47 are the same as those of the friction material 41 of the first embodiment. For this reason, the friction material 47 of this embodiment has a smaller diameter and a smaller area than the friction material 40 of Comparative Example 1. Therefore, also in this embodiment, the same effect as the first embodiment can be obtained. In addition, since the diameter of a friction material can be made smaller than this Embodiment and the area of a friction material can be made smaller than 3rd Embodiment, the higher effect than 3rd Embodiment is acquired.

(Other embodiments)
(1) As for the number and layout of the plurality of slits 13c, 13d, 13e, 20c, and 20d that constitute the magnetic shielding portion in each of the above-described embodiments, the respective slits 13c, 13d, 13e, 20c, and 20d are shown. You may change to a different number or layout.

  (2) In each of the above-described embodiments, the magnetic shielding portion is configured by the plurality of slits 13c, 13d, 13e, 20c, and 20d, that is, the space. However, the present invention is not limited to this. The magnetic shielding part may be made of a nonmagnetic material. For example, in the first embodiment, the armature 20 is divided into an inner peripheral portion and an outer peripheral portion, and the inner peripheral portion and the outer peripheral portion sandwich one annular nonmagnetic material. May be.

  (3) In each of the above embodiments, the present invention is applied to an electromagnetic clutch that attracts the armature 20 to the rotor 10 by the magnetic force generated by the electromagnetic coil. However, the present invention can also be applied to a clutch that uses a permanent magnet. It is. A clutch that uses a permanent magnet maintains, for example, the connection state between the rotor and the armature by the magnetic force of the permanent magnet, and the same direction as the flow direction of the magnetic flux by the permanent magnet with respect to the magnetic circuit formed by the permanent magnet. Alternatively, the rotor and the armature are switched between connection and disconnection by generating a magnetic flux with an electromagnetic coil so as to give a magnetic flux in the reverse direction.

  (4) The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope described in the claims, and includes various modifications and modifications within the equivalent range. Further, the above embodiments are not irrelevant to each other, and can be combined as appropriate unless the combination is clearly impossible. In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily essential unless explicitly stated as essential and clearly considered essential in principle. Yes. Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is clearly limited to a specific number when clearly indicated as essential and in principle. The number is not limited to the specific number except for the case. In each of the above embodiments, when referring to the material, shape, positional relationship, etc. of the constituent elements, etc., unless otherwise specified, or in principle limited to a specific material, shape, positional relationship, etc. The material, shape, positional relationship, etc. are not limited.

(Summary)
According to the 1st viewpoint shown by one part or all part of said each embodiment, the friction material is arrange | positioned in the position which overlaps with the armature side magnetic shielding part in the axial direction of a rotation centerline.

  Moreover, according to the 2nd viewpoint, the friction material is arrange | positioned in the position which overlaps with the axial direction of a rotation center line with respect to an inner peripheral side magnetic shielding part.

  Moreover, according to the 3rd viewpoint, the inner peripheral side magnetic interruption | blocking part is one. There is one armature-side magnetic shield. The armature-side magnetic shielding part is disposed on the outer side in the radial direction of the armature with respect to the inner peripheral side magnetic shielding part. Thus, it is preferable to employ a configuration in which one inner peripheral side magnetic shielding portion and one armature side magnetic shielding portion are formed.

10 Rotor 13a Friction surface of rotor (contact surface of rotor)
13c 1st slit (periphery side magnetic shielding part)
13d 3rd slit (inner magnetic shield)
20 Armature 20a Friction surface of armature (armature contact surface)
20c 2nd slit (armature side magnetic shielding part)
41 Friction material 43 Friction material

Claims (3)

A rotor (10) made of a magnetic material, which receives a rotational driving force from a driving source and rotates around a rotation center line (O);
An armature (20) that is made of a magnetic material and is attracted to the rotor by a magnetic force to transmit the rotational driving force;
Each of the rotor and the armature has a contact surface (13a, 20a) that comes into contact with a counterpart when the armature is attracted to the rotor,
The contact surface (13a) of the rotor has a shape along a circumferential direction centering on the rotation center line, and an outer peripheral side magnetic shielding portion (13c) that blocks a magnetic flux flow, and the outer peripheral side magnetic shielding portion Are arranged on the rotation center side, and have a shape along the circumferential direction centering on the rotation center line, and are formed with inner circumference side magnetic shielding portions (13d, 13e) that block the magnetic flux flow,
The armature contact surface (20a) is disposed closer to the rotation center than the outer peripheral magnetic shield, and has a shape along a circumferential direction centering on the rotation center line, and blocks the magnetic flux flow. Side magnetic shields (20c, 20d) are formed,
Further, the contact surface of the armature is provided with a friction material (41, 45) made of a non-magnetic material in an annular shape continuous over the entire circumferential direction,
The clutch is disposed at a position where the friction material overlaps with the armature-side magnetic shielding portion in an axial direction of the rotation center line. A rotor (10) made of a magnetic material, which receives a rotational driving force from a driving source and rotates around a rotation center line (O);
An armature (20) that is made of a magnetic material and is attracted to the rotor by a magnetic force to transmit the rotational driving force;
Each of the rotor and the armature has a contact surface (13a, 20a) that comes into contact with a counterpart when the armature is attracted to the rotor,
The contact surface (13a) of the rotor has a shape along a circumferential direction centering on the rotation center line, and an outer peripheral side magnetic shielding portion (13c) that blocks a magnetic flux flow, and the outer peripheral side magnetic shielding portion Are arranged on the rotation center side, and have a shape along the circumferential direction centering on the rotation center line, and are formed with inner circumference side magnetic shielding portions (13d, 13e) that block the magnetic flux flow,
The armature contact surface (20a) is disposed closer to the rotation center than the outer peripheral magnetic shield, and has a shape along a circumferential direction centering on the rotation center line, and blocks the magnetic flux flow. Side magnetic shields (20c, 20d) are formed,
Furthermore, the contact surface of the rotor is provided with a friction material (43, 47) made of a non-magnetic material in an annular shape that is continuous over the entire circumferential direction,
The clutch is disposed at a position where the friction material overlaps with the inner peripheral magnetic shielding portion in the axial direction of the rotation center line. The inner circumference side magnetic shielding part (13d) is one,
The armature side magnetic shielding part (20c) is one,
3. The clutch according to claim 1, wherein the armature-side magnetic cutoff portion is disposed on a radially outer side of the armature with respect to the inner peripheral side magnetic cutoff portion.

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