JPH0744360U - Electromagnetic clutch - Google Patents

Abstract

(57) [Summary] [Purpose] By not arranging ribs in a row in the radial direction,
By increasing the torque transmission by reducing the leakage magnetic flux, the bending stress is evenly distributed by gradually increasing the rib width toward the radial center. The electromagnetic clutch rotor has an axial end plate with a plurality of concentric rings, each concentric ring being defined by alternating arcuate slits and ribs.
The arcuate slits form magnetic poles on the opposite side so that the magnetic flux passes through the zigzag path between the axial end plate and the armature. The ribs on adjacent concentric rings are not aligned in a radial direction, which reduces the amount of magnetic flux leaking through the axial end plates. In addition, the ribs gradually increase in size toward the radial center in order to absorb the bending stress that increases toward the center of the axial end plate.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic clutch, and more particularly to a clutch rotor designed to reduce the amount of magnetic flux leaking through the rotor and a structure of the clutch rotor designed to evenly distribute the driving force across the rotor radius. It is about.

[0002]

[Prior art]

 Electromagnetic clutches are well known in the art and can be used to control power transfer from an automobile engine to a refrigerant compressor of an automobile air conditioner. The structure of the electromagnetic clutch of a general automobile air conditioner is disclosed in U.S. Pat. Nos. 3,044,594 and 3,082,933.

The structure of the electromagnetic clutch is shown in FIG. The clutch assembly is arranged on the outer peripheral edge of the circular tubular extension 2 projecting from the end face of a compressor housing (not shown) arranged so as to surround the drive shaft 3. The clutch assembly comprises a rotor 5 rotatably mounted on the tubular extension 2 by bearings 6. The rotor 5 is driven by a belt connected to a motor vehicle engine (not shown). As shown in FIG. 2, the axial end plate 5d 'of the rotor 5 has a plurality of concentric rings 50', 52 ', 54'. The concentric rings 50 ', 52', 54 'are defined by alternating a plurality of arcuate slits 5a', 5b ', 5c' and ribs 200 ', 202', 204 '. . That is, the inner ring 50 'is defined by alternately arranging a plurality of arcuate slits 5a' and ribs 200 ', and the intermediate ring 52' defines a plurality of arcuate slits 5b 'and ribs 202'. Alternately defined, the outer peripheral ring 54 'is similarly defined by alternating multiple arcuate slits 5c' and ribs 204 '. The slits 5a 'and 5b'5c' form magnetic poles on the axial end plate 5d 'of the rotor 5.

The axial end plate 5d 'of FIG. 2 forms a 6-pole clutch part. In this configuration, the three concentric rings 50 ', 52', 54 'pass less magnetic flux than the rest of the rotor. One pole face is defined by the annular portion of the disk located radially inward of the inner ring 50 '. The two pole faces are defined by the annulus between the inner ring 50 'and the intermediate ring 52'. Further, the two pole faces are defined by an annulus between the intermediate ring 52 'and the outer ring 54'. The sixth pole face is defined by an annulus located outside the outer ring 54 '.

The hub 7 is fixed to the outer end of the drive shaft 3 extending beyond the tubular extension 2. The armature 8 is fixedly connected to the hub 7 by a plurality of leaf springs 9. The leaf spring 9 is fixed to the outer surface of the armature 8 by a rivet 11. The axial end face of the armature 8 faces the axial end plate 5d of the rotor with a constant axial gap G. The axial end surface of the armature 8 has concentric arcuate slits 8a and 8b forming a polar surface 8c. The slit 8a is located so as to face the midpoint between the slits 5b and 5c on the axial end plate 5d, and the slit 8b faces the midpoint between the slits 5b and 5a on the axial end plate 5d. Is located as.

The electromagnet 10 is mounted on the compressor housing concentrically with the drive shaft 3. The excitation coil 101 is arranged in the annular space 5e of the rotor 5 and is surrounded by a gap. When the exciting coil 101 of the electromagnet 10 is energized, the pole face 8c is attracted to the axial end plate 5d. As a result, the drive shaft 3 rotates when the rotor 5 is rotated by the engine. When the energization of the exciting coil 101 of the electromagnet 10 is stopped, the pole face 8c of the armature 8 is separated from the axial end plate 5d by the restoring force of the leaf spring 9. The rotor 5 rotates as it is according to the engine output, but the drive shaft 3 does not rotate.

A magnetic flux M generated by energizing the exciting coil 101 so as to surround the electromagnet 10 passes through a magnetic path formed in the electromagnet 10, the rotor 5 and the armature 8. Since the magnetic flux M tends to flow along the shortest path through the magnetic path, the magnetic flux M passes through the rotor 5 and the armature 8 in a zigzag manner as shown by the wavy line in FIG.

[0008]

[Problems to be solved by the device]

 However, in the conventional axial endplate structure of FIG. 2, all ribs 200 ', 202', 204 'are aligned in line along the same radius R'. In addition, the angle θ1 ′ between the ribs 200 ′ on the inner ring 50 ′ is the same as the angle θ2 ′ between the ribs 202 ′ on the intermediate ring 52 ′, and the ribs 204 ′ on the outer ring 54 ′ are the same. The angle θ3 ′ between them is the same as the angle θ1 ′ and the angle θ2 ′. As a result, some magnetic flux passes through the ribs 200 ', 202', 204 'arranged in the radial direction. In the conventional electromagnetic clutch, the leakage amount of the magnetic flux passing through the ribs 200 ', 202', 204 'arranged in the radial direction may be 25% or more of the total magnetic flux generated by the electromagnet. As a result, the suction force between the axial end plate and the armature is reduced. To compensate for this flux leakage, the number of turns in the electromagnet coil must be increased in proportion to the size of the compressor.

In addition, the rotor of FIG. 1 has a plurality of V-grooves for connecting with a plurality of belts. Therefore, a large bending moment is applied to the rotor by the belt. The bending moment is alternately transmitted to the ribs 200 ', 202', 204 ', and the bending stress is expressed by the following equation. Bending stress: S = M / Z (1) Bending moment: M = W * l (2) Section coefficient: Z = (b * h ₂ ) / 6 (3) S is bending stress, M is bending moment, W is belt load, l is rib length from position of load W, Z is section coefficient, and b is The rib width, h is the thickness of the friction surface portion of the rotor.

For example, referring to FIG. 3, a diagram of a rotor having relative radial positions of ribs is shown. If the load W of the belt is 10 kg and the length l of the ribs 204 ', 202', 200 'from the position of the load W is 1 cm, 2 cm, 4 cm, respectively, the ribs 204' will produce The bending moment M is 10 Kg-cm, 20 Kg-cm for the rib 202 'and 40 Kg-cm for the rib 200'. Therefore, when the bending moment in the above equation (1) is applied, the bending stress of each rib 204 ', 202'200' becomes as follows. S204 '= 10 / Z S202' = 20 / Z S200 '= 40 / Z

If the ribs have the same section modulus (ie, if the widths between the ribs are all equal, W1 '= W2' = W3 '), the maximum bending stress occurs in the rib 200'. As a result, the ribs must have a maximum width at their radially innermost positions, if designed to evenly distribute their bending moments. Therefore, the ribs 200 'must have a maximum width. However, all ribs of a conventional rotor are identical in vertical size, regardless of their relative radial position on the rotor. As a result, the ribs on the inner circumference are more susceptible to metal fatigue than the ribs on the outer circumference.

[0012]

[Means for Solving the Problems]

 According to the present invention, the at least first radial inner circumferential concentric ring and the second radial outer circumferential concentric ring are supported by the first bearing and are made of a magnetic material. A first rotating member having an axial end plate having a plurality of concentric slits arranged on one ring, a plurality of magnetic poles defined by the concentric ring, and a second rotating member rotatably supported by the main shaft. Magnetic member that is connected to the second rotatable member so as to be movable in the constant axial direction and that faces the axial end plate of the first rotatable member with a constant axial gap. An annular armature comprising: and an electromagnetic means cooperating with the axial end plate for attracting the armature so that rotational force may be transmitted to the second rotatable member. One rotating member An electromagnetic clutch is characterized in that ribs are arranged between adjacent slits on the respective concentric rings, and the width of the ribs of the first concentric ring is larger than the width of the ribs of the second concentric ring. can get.

Further, according to the present invention, the axial end plate of the first rotatable member has a radial direction so that bending stress is evenly distributed with respect to the radius of the axial end plate. An electromagnetic clutch is obtained which has ribs that gradually widen toward the center.

Furthermore, according to the present invention, none of the ribs of the inner peripheral concentric ring are radially aligned with the ribs of the middle concentric ring, and the middle concentric ring is aligned with the ribs on the outer peripheral concentric ring. An electromagnetic clutch is obtained which is not arranged in a line in the radial direction.

[0015]

【Example】

 The same elements as in the past are denoted by the same reference numerals without a dash. The structure of the electromagnetic clutch according to the embodiment is substantially the same as that shown in FIG. However, the electromagnetic clutch carries a rotor with axial end plates 5d as shown in FIG.

According to an embodiment, the axial end plate 5d is formed with a plurality of concentric rings 50, 52, 54 shown in FIG. However, rotors with only two or more than four concentric rings are also possible embodiments. The concentric ring is defined by a plurality of alternating arcuate slits 5a, 5b, 5c and ribs 200, 202, 204. For example, the inner circumferential concentric ring 50 is defined by a plurality of alternating arcuate slits 5a and ribs 200. The intermediate concentric ring 52, on the other hand, is defined by a plurality of alternating arcuate slits 5b and ribs 202. The outer peripheral concentric ring 54 is defined by a plurality of alternating arcuate slits 5c and ribs 204. The spaces created by the slits 5a, 5b, 5c form air gaps that resist the flow of magnetic flux, thus creating magnetic poles on the opposite sides of the individual slits. For example, the hexapole is formed on the axial end plate of FIG. In particular, one magnetic pole surface is defined by an annular portion located radially inward of the inner peripheral ring 50, and two magnetic pole surfaces are defined by an annular portion between the inner peripheral ring 50 and the intermediate ring 52. Two magnetic pole faces are defined by an annular portion between the intermediate ring 52 and the outer peripheral ring 54, and a sixth magnetic pole face is defined by an annular portion located outside the outer peripheral ring 54. .

The width of the ribs on each individual concentric ring is desirably substantially the same as the width of the other ribs on the same concentric ring. For example, all ribs 200 on inner ring 50 have a width of W1, all ribs 202 on middle ring 52 have a width of W2, and all ribs 204 on outer ring 54 have a width of W3. have. However, there may be some deviation between the widths of the ribs on the same concentric ring. Similarly, the arc lengths of arcuate slits on individual concentric rings are substantially the same as the arc lengths of other arcuate slits on the same concentric ring. However, some deviations may exist between arc lengths of arcuate slits on the same concentric ring. Instead of maintaining substantially equal arcuate slit arc lengths and rib widths on the same concentric ring, the significant rib-to-arc slit relationship is between them on different concentric rings. .

For example, in FIG. 4, the width W1 of the rib 200 on the inner circumferential concentric ring 50 is designed to be larger than the width W2 of the rib 202 on the intermediate concentric ring 52. Similarly, the width W2 of the rib 202 on the intermediate concentric ring 52 is designed to be larger than the width W3 of the rib 204 on the outer peripheral concentric ring 54. These different widths cause different bending stresses that occur along the radius of the axial end plate 5d. In particular, the ribs 200 of the inner peripheral concentric ring 50 are farthest from the application of the belt load, so that the ribs generate the largest bending stress. As a result, the rib 200 of the inner peripheral concentric ring 50 needs to be maximized. On the other hand, the ribs 204 of the outer peripheral concentric ring 54 are closest to the application of belt load. As a result, the ribs 204 of the outer peripheral concentric ring 54 need a minimum width. By gradually increasing the rib width toward the radial center of the axial end plate 5d, the bending stress is more evenly distributed along the radius of the axial end plate.

In addition, the ribs 200 on the inner concentric ring 50 are not radially aligned with the ribs 202 on the intermediate concentric ring 52, and the ribs 202 on the intermediate concentric ring 52 are It does not line up with the upper rib 204 in the radial direction. As a result, the magnetic flux is passed through the zigzag passage between the slits 5a, 5b, 5c on the axial end plate 5d and the slits 8a, 8b on the armature plate 8. By not arranging the ribs in the radial direction, the magnetic flux leaking through the ribs is reduced, so that the attractive force of the electromagnetic clutch is increased. For example, when read in connection with FIG. 5, Table 1 shows that all ribs in the axial end plate are radial with respect to the amount of magnetic flux leaking when the axial end plate is designed according to this embodiment. It shows the amount of magnetic flux that leaks when it is designed to be arranged in. In FIG. 5, the leakage magnetic flux ML is shown by a broken line, and the main magnetic flux M is shown by a solid line. Table 1 Positioning Conventional Example A _{22.7% 17.6%} B _{28.3% 10.6%} C _{21.0% 17.6%}

As a result, at the point A, the leakage magnetic flux (the magnetic flux not contributing to the attraction between the rotor and the armature) due to the conventional axial end plate is equal to the total magnetic flux._22.7%On the other hand, the leakage magnetic flux in this embodiment is_17.6%(Compared to conventional_5.1%Decrease). At point B, the leakage flux due to the conventional axial end plate is about the original flux._28.3%On the other hand, the leakage magnetic flux in this embodiment is_10.6%(Compared to conventional_17.7%Decrease). Finally, at point C, the leakage flux due to the conventional axial end plate is about the original flux._{twenty one .0%} On the other hand, the leakage magnetic flux in this example is_17.6%(Compared to conventional_3.4%Decrease). In the axial end plate of FIG. 4, the inner concentric ring 50 has more ribs and arcuate slits than the intermediate concentric ring 52 or the outer concentric ring 54. However, the ribs 200 of the inner circumferential concentric ring 50 are not aligned with the ribs 202 of the middle concentric ring 52 in the radial direction, and the ribs 200 of the inner circumferential concentric ring 50 are wider than the ribs of the middle concentric ring 52. As long as the inner concentric ring 50 and the intermediate concentric ring 52 can be manufactured with the same number of ribs. This is illustrated by the relationship between the intermediate concentric ring 52 and the outer concentric ring 54. In particular, the intermediate concentric ring 52 and the outer concentric ring 54 have the same number of ribs. However, the ribs 202 of the intermediate concentric ring 52 are not radially aligned with the ribs 204 of the outer concentric ring 54, and the ribs 202 on the intermediate concentric ring 52 are wider than the ribs 204 on the outer concentric ring 54. Has become.

In order to maintain the relationship of the formula defined in the background of the invention, by designing the axial end plate 5d with an appropriate number of ribs on each concentric ring, the axial direction according to the present embodiment The end plate is manufactured with an angle θ1 between the centers of adjacent ribs 200 on the inner circumferential concentric ring 50 that is less than the angle θ3 between the centers of the ribs 204 on the outer circumferential concentric ring 54. In the embodiment, the center-to-center angle θ2 of the ribs 202 on the intermediate concentric ring 52 is the same as the center-to-center angle θ3 of the ribs 204 on the outer peripheral concentric ring 54. However, it is within the scope of the invention to have five slits 5b on the intermediate concentric ring 52, instead of the four slits 5d shown in FIG. In that case, the center-to-center angle θ2 of the rib 202 on the intermediate concentric ring 52 is smaller than the center-to-center angle θ3 of the rib 204 on the outer peripheral concentric ring 54. The center-to-center angle of ribs on any concentric ring will be equal to or less than the center-to-center angle of all adjacent outer concentric rings. This relationship ensures that the bending stress is evenly distributed across the radius of the axial end plate.

[0022]

[Effect of device]

 By arranging the arcuate slits formed on the axial end plate of the rotor of the electromagnetic clutch so that they are not aligned in the radial direction, it is possible to reduce the amount of electromagnetic flux that leaks through the rotor and armature. As a result, the torque transmission of the electromagnetic clutch can be increased.

Further, the axial end plate of the rotor has ribs that gradually widen toward the center in the radial direction, and the ribs of the inner peripheral concentric ring are arranged in a line in the radial direction with the ribs of the intermediate concentric ring. Since they are arranged side by side, the bending stress from the belt is evenly distributed with respect to the radius of the axial end plate.

The present invention has been described in detail according to the embodiments, but is not limited to the embodiments. It will be readily understood by those skilled in the art that other modifications can be easily made within the scope of the embodiments.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional electromagnetic clutch.

FIG. 2 is a plan view of a conventional axial end plate on an electromagnetic clutch rotor.

FIG. 3 is a diagram of a clutch rotor showing the application of driving force and the relative distance between the ribs on the rotor.

FIG. 4 is a plan view of a rotor according to a preferred embodiment.

FIG. 5 is a partial cross-sectional view of an electromagnetic clutch showing a magnetic flux of an electromagnet.

[Explanation of symbols]

 5a, 5b, 5c slit 8 armature 8a, 8b slit 50 inner peripheral concentric ring 52 intermediate concentric ring 54 outer peripheral concentric ring 200, 202, 204 rib

Claims (1)

[Scope of utility model registration request] 1. A first bearing supported on the first bearing, and
An axial end plate made of a magnetic material and having a plurality of concentric slits arranged on at least two rings defining at least a first radial inner peripheral concentric ring and a second radial outer peripheral concentric ring. A first rotating member, a plurality of magnetic poles defined by the concentric ring, a second rotating member rotatably supported by a main shaft, and a second rotatable member movably in a constant axial direction. And an annular armature made of a magnetic material facing the axial end plate of the first rotatable member with a constant axial gap, and the rotational force is transmitted to the second rotatable member. And an electromagnetic means cooperating with the axial end plates for attracting the armature so that the first rotating member has ribs between adjacent slits on individual concentric rings. And An electromagnetic clutch, wherein the width of the rib of the first concentric ring is larger than the width of the rib of the second concentric ring.