JP2001056033A - Electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic clutch having a small number of parts, reducing volume of rubber of a rubber damper for armature movement and low in cost. SOLUTION: The neighbourhood of each apex angle of a roughly triangular boss 4 screwed in an axis of rotation of a compressor, etc., is formed in a circular arc protruded part 4A. Circular arc recessed parts 5A are formed at three points on an inner peripheral surface of a drilled disc type armature 5, and each of the recessed parts is fitted in each of the protruded parts of the boss with a certain clearance. When a magnetizing device of an electromagnetic clutch is magnetized, the armature slightly moves in a direction orthogonal with a paper surface against the boss and it makes contact with a rotor such as a pulley, etc. When the rotor rotates in the arrow direction, the armature also moves in the same direction. Consequently, the armature slightly idles at the first stage of rotation, and after each of the recessed parts makes contact with each of the protruded parts, the boss is rotated by the armature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electromagnetic clutch used for a power transmission mechanism for transmitting power from a rotor such as a pulley to a rotating shaft such as a compressor.

[0002]

2. Description of the Related Art First, a first conventional electromagnetic clutch will be described with reference to FIGS.

An inner ring of a ball bearing 21 is fixed to a front nose (not shown) of the compressor, and an inner peripheral surface of a pulley 22 is fixed to an outer ring of the ball bearing 21. An excitation device 23 is housed inside.

A circular boss 24 is fitted to a rotary shaft (not shown) of the compressor by splines or serrations, and is fixed by a nut so as not to move in the axial direction. A perforated disk-shaped armature 25 is arranged on one side of the pulley 22 so as to face the armature 25. The armature 25 can be slightly moved in the direction of the rotation axis of the compressor by the excitation demagnetization of the excitation device 23. it can. Three places on one side of the armature 25 and three places on one side of the boss 24 are connected by three leaf springs 26 and six rivets 27.

A substantially triangular plate 28 is fixed to one side surface of the boss 24 by three rivets 29. A rubber damper 30 is mounted near each vertex of the plate 28. Each rubber damper 30
Is a rivet 30A and a thick shaft portion 30A of the rivet 30A.
2 and a ring-shaped rubber 30B that fits into the ring.
Each rivet 30A has a head 30A1 and a thick shaft 30A2.
And a thin shaft portion 30A3 and an armature suppressing portion 30A4. The cuts 30B1 formed on the outer peripheral surface of each rubber 30B are inserted into holes 28A provided near each apex angle of the plate 28, and the fine shaft portion 30A3 of each rivet 30A is inserted into each hole 25 provided in the armature 25.
Inserted into A. Furthermore, the thick shaft portion 30 of each rivet 30A
The armature 25 is clamped between A2 and the armature holding portion 30A4.

FIG. 7A shows that the excitation device 23 is demagnetized,
This shows a state where a slight clearance exists between the left side surface of the pulley 22 and the right side surface of the armature 25. When the exciting device 23 is excited, the armature 25 is attracted to the exciting device 23, so that each of the three leaf springs 26 bends. Therefore, the armature 25 has the boss 2
The armature 25 slightly moves to the right with respect to 4, and the right side surface of the armature 25 and the left side surface of the pulley 22 come into contact with each other. At this time, the rubber 30B is compressed between the plate 28 and the head 30A1 of the rivet 30A.

When the pulley 22 rotates, as shown in FIG. 8, the armature 25 also rotates in the same direction as the pulley 22 by frictional force. Further, the armature 25 pulls the boss 24 by three leaf springs 26 and rotates the boss 24 in the same direction. Therefore, the rotating shaft of the compressor also rotates, and the compressor performs its intended operation.

When the exciting device 23 is demagnetized, the armature 25 is not attracted to the exciting device 23, and thus slightly moves leftward with respect to the boss 24 by the restoring force of the rubber 30B. Therefore, the right side surface of the armature 25 and the left side surface of the pulley 22 are separated from each other.
Even if 2 rotates, power is not transmitted.

Next, a second conventional electromagnetic clutch will be described with reference to FIG. However, description of the same portions as those of the first electromagnetic clutch of the related art will be omitted. In addition,
This type of technique is described in Japanese Utility Model Laid-Open No. 61-89526.

A substantially triangular plate 45 is provided on the boss 44.
Are fixed by three rivets 46. Near each apex angle of the plate 45, a rubber damper 47 is provided.
Is installed. Each rubber damper 47 includes a rivet 47A, a head 47A1 of the rivet 47A, and a thick shaft portion 4.
A ring-shaped rubber 47B that fits into 7A2 and a rubber 47
B holding member 47C. Each rivet 47
A is a head portion 47A1, a thick shaft portion 47A2, and a thin shaft portion 47A.
A3 and an armature suppressing portion 47A4. Each holding member 47C is fixed to the plate 45, and the thick shaft portion 47A2 of each rivet 47A passes through the hole 47C1 of each holding member 47C and each hole 45A of the plate 45. Holes 4 provided at three places of perforated disk-shaped armature 48
8A fits into the narrow shaft portion 47A3 of each rivet 47A, and the armature 48 is clamped between the thick shaft portion 47A2 of each rivet 47A and the armature pressing portion 47A4.

When the exciting device (not shown) is excited, the armature 48 moves slightly rightward in FIG. 9A, so that each rubber 47B is attached to the head 4 of each rivet 47.
It is pressed by 7A1 and compressed in each holding member 47C.
When a rotor (not shown) such as a pulley rotates, the armature 48 also rotates in the same direction, and the rotational force is transmitted from the armature 48 via each rivet 47A, each rubber 47B, each holding member 47C, the plate 45, and each rivet 46. It is transmitted to the boss 44.

When the excitation device is demagnetized, the armature 4
8 returns to the position shown in FIG. 9A by the restoring force of each rubber 47B, so that no rotational force is transmitted thereafter.

[0013]

The first conventional electromagnetic clutch has the following disadvantages. That is, a plurality of leaf springs and a plurality of rivets are required for connecting the armature and the boss. Therefore, the number of parts is large, the cost is high, and assembly and disassembly are complicated.

The second conventional electromagnetic clutch has the following disadvantages. That is, in order to transmit a large rotational force from the armature to the boss, the volume of the rubber must be increased, and the cost of the rubber damper increases. Furthermore, when the volume of rubber increases,
Since the spring constant increases, the attraction voltage of the excitation device also increases.

Therefore, the present invention is to improve the drawbacks of the conventional electromagnetic clutches, to provide an electromagnetic clutch having a small number of parts, a small rubber volume of a rubber damper for moving an armature, and a low cost. It is assumed that.

[0016]

The present invention employs the following means to solve the above-mentioned problems.

1. Protrusions or depressions are formed at a plurality of locations on the outer peripheral surface of the boss, and depressions or projections corresponding to the projections or the depressions are formed at a plurality of locations on the inner peripheral surface of the armature,
A clearance exists between the convex or concave portion of the boss and the concave or convex portion of the armature so as not to hinder the movement of the armature at the time of excitation and demagnetization of the electromagnetic clutch. An electromagnetic clutch transmitted from the concave portion or the convex portion of the armature to the convex portion or the concave portion of the boss.

2. 2. The electromagnetic clutch according to claim 1, wherein at least the convex portion or the concave portion of the boss and at least the concave portion or the convex portion of the armature are subjected to heat treatment to improve hardness.

3. 2. The electromagnetic clutch according to claim 1, wherein the protrusion or the recess of the boss and the recess or the protrusion of the armature are provided with a wear-resistant coating.

4. 2. The electromagnetic clutch according to claim 1, wherein the convex portion or the concave portion of the boss and the concave portion or the convex portion of the armature are formed of separate parts having wear resistance.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electromagnetic clutch according to five embodiments of the present invention will be described.

First, a first embodiment of the present invention will be described with reference to FIGS.

An inner ring of a ball bearing 1 is fixed to a front nose (not shown) of the compressor, and an inner peripheral surface of a pulley 2 is fixed to an outer ring of the ball bearing 1. The excitation device 3 is housed inside.

A substantially triangular boss 4 is fitted to a rotating shaft (not shown) of the compressor by splines or serrations, and is fixed by a nut so as not to move in the axial direction. The vicinity of each apex angle of the boss 4 is formed in an arc-shaped convex portion 4A. A perforated disk-shaped armature 5 is disposed on one side of the pulley 2 so as to face the armature 5, and the armature 5 can slightly move in the direction of the rotation axis of the compressor due to the excitation demagnetization of the excitation device 3. it can.
At three places on the inner peripheral surface of the armature 5, arc-shaped concave portions 5 are provided.
A is formed, and each concave portion 5A is fitted in each convex portion 4A of the boss 4 with a slight clearance.

An approximately triangular plate 6 is fixed to one side surface of the boss 4 by three rivets 7. A rubber damper 8 is mounted near each vertex of the plate 6. Each rubber damper 8 is a rivet 8A
And a ring-shaped rubber 8B that fits into the thick shaft portion 8A2 of the rivet 8A. Each rivet 8A has a head 8
A1, a thick shaft portion 8A2, a thin shaft portion 8A3, and an armature suppressing portion 8A4. The cut 8B1 formed on the outer peripheral surface of each rubber 8B is inserted into a hole 6A provided near each vertex of the plate 6, and each rivet 8
The fine shaft portion 8A3 of A is provided with each hole 5 provided in the armature 5.
B is inserted. Furthermore, the thick shaft portion 8A2 of each rivet 8A
Between the armature holding portion 8A4 and the armature 5
Are pinched.

FIG. 1A shows a state in which the exciting device 3 is demagnetized and a slight clearance exists between the left side surface of the pulley 2 and the right side surface of the armature 5. When the exciting device 3 is excited, the armature 5 is slightly attracted to the exciting device 3 and moves slightly to the right with respect to the boss 4.
The right side surface of the armature 5 and the left side surface of the pulley 2 are in contact with each other. At this time, the rubber 8B is compressed between the plate 6 and the head 8A1 of the rivet 8A.

When the pulley 2 rotates, as shown in FIG. 2, the armature 5 also rotates in the same direction with the pulley 2 by frictional force. The armature 5 slightly idles at the beginning of the rotation, and the boss 4 is rotated by the armature 5 after the three concave portions 5A come into contact with the three convex portions 4A of the boss 4. Therefore, the rotating shaft of the compressor also rotates, and the compressor performs its intended operation.

When the exciting device 3 is demagnetized, the armature 5 is not attracted to the exciting device 3, so that the rubber 8B
Moves slightly to the left with respect to the boss 4 due to the restoring force. Therefore, the right side of the armature 5 and the pulley 2
Because it is separated from the left side surface, even if the pulley 2 rotates,
Power is not transmitted.

Next, a second embodiment of the present invention will be described with reference to FIG. In the following embodiment, description of the same parts as those in the first embodiment will be omitted.

In the second embodiment, a substantially circular boss 9 having serrated projections 9A formed at 12 places on the outer peripheral surface is provided.
A perforated disk-shaped armature 10 having serrated concave portions 10A formed at 12 places on the inner peripheral surface is employed. As described above, when the contact area between the boss 9 and the armature 10 is increased as compared with the first embodiment, wear of both parts is reduced.

Next, a third embodiment of the present invention will be described with reference to FIG.

In the third embodiment, a substantially square boss 11 having arc-shaped projections 11A formed at four corners, and a hole having arc-shaped recesses 12A formed at four locations on the inner peripheral surface. And a disk-shaped armature 12. Boss 1 like this
When the contact area between the armature 1 and the armature 12 is slightly increased as compared with the first embodiment, the friction between both parts is slightly reduced.

Further, a fourth embodiment of the present invention will be described with reference to FIG.

In the fourth embodiment, a substantially rhombus-shaped boss 13 having two arc-shaped convex portions 13A is formed, and a perforated hole having two arc-shaped concave portions 14A formed in the inner peripheral surface. A disk-shaped armature 14 is employed. With this configuration, the structure of both parts is simplified as compared with the first embodiment.

Further, a fifth embodiment of the present invention will be described with reference to FIG.

In the fifth embodiment, a boss 15 having a long-diameter / long-peripheral projection 15A formed at three locations on the outer peripheral surface and a hole having a long-diameter / long-peripheral recess 16A formed at three locations on the inner peripheral surface are provided. A bright disk-shaped armature 16 is employed. With this configuration, a strong rotational force can be transmitted from the armature 16 to the boss 15.

In each of the embodiments of the present invention, the convex portion is formed on the boss and the concave portion is formed on the armature, but the design is changed so that the concave portion is formed on the boss and the convex portion is formed on the armature. Can be.

Further, the following method can be adopted to prevent abrasion of the contact portion between the boss and the armature.

1. Heat treatment is performed on at least the convex portions or concave portions of the boss and at least the concave portions or convex portions of the armature to improve the hardness.

2. A wear-resistant coating is applied to the projections or depressions of the boss and the depressions or projections of the armature.

3. The projections or depressions of the boss and the depressions or projections of the armature are composed of separate parts having wear resistance.

[0042]

As is apparent from the above description, the present invention has the following advantages.

1. Since the rotational force of a rotor such as a pulley is transmitted directly from an armature to a rotating shaft of a compressor or the like via a boss, conventional leaf springs and fixing rivets can be eliminated. Therefore, the number of parts is reduced, and an electromagnetic clutch with low cost can be obtained.

2. The reduction in the number of parts makes assembly and disassembly of the electromagnetic clutch simple and convenient.

3. Since the rubber damper is used only for the movement of the armature during excitation demagnetization and is not used for transmitting the rotational force, the volume of the rubber is reduced, and the attraction voltage of the excitation device is also reduced.

4. In the first, third, fourth, and fifth embodiments, the rotational force can be transmitted from the armature to the boss in any direction.

[Brief description of the drawings]

FIG. 1 shows an electromagnetic clutch according to a first embodiment of the present invention, wherein (a) is a sectional view and (b) is a front view.

FIG. 2 is a front view of a main part of the electromagnetic clutch according to the first embodiment of the present invention.

FIG. 3 is a front view of a main part of an electromagnetic clutch according to a second embodiment of the present invention.

FIG. 4 is a front view of a main part of an electromagnetic clutch according to a third embodiment of the present invention.

FIG. 5 is a front view of a main part of an electromagnetic clutch according to a fourth embodiment of the present invention.

FIG. 6 is a front view of a main part of an electromagnetic clutch according to a fifth embodiment of the present invention.

7A and 7B show a first conventional electromagnetic clutch, in which FIG. 7A is a sectional view and FIG. 7B is a front view.

FIG. 8 is a front view of a main part of a first conventional electromagnetic clutch.

9 (a) is a sectional view and FIG. 9 (b) is a front view of a main part of a second conventional electromagnetic clutch.

[Description of Signs] 1 Ball bearing 2 Pulley 3 Exciting device 4 Boss 4A Convex part 5 Armature 5A Concave part 5B Hole 6 Plate 6A Hole 7 Rivet 8 Rubber damper 8A Rivet 8A1 Head 8A2 Thick shaft part 8A3 Fine shaft part 8A4 8B Rubber 8B1 Cut 9 Boss 9A Convex portion 10 Armature 10A Concave portion 11 Boss 11A Convex portion 12 Armature 12A Concave portion 13 Boss 13A Convex portion 14 Armature 14A Concave portion 15 Boss 15A Convex portion 16 Armature 16A Concave portion

Claims (4)

[Claims] 1. A boss or a recess is formed at a plurality of locations on an outer peripheral surface of a boss, and a recess or a projection corresponding to the projection or the recess is formed at a plurality of locations on an inner peripheral surface of an armature. A clearance exists between the protrusion or the recess and the recess or the protrusion of the armature so as not to hinder the movement of the armature at the time of excitation and demagnetization of the electromagnetic clutch. The electromagnetic clutch is transmitted from the concave portion or the convex portion to the convex portion or the concave portion of the boss. 2. The electromagnetic clutch according to claim 1, wherein the hardness is improved by performing a heat treatment on at least the convex portion or the concave portion of the boss and at least the concave portion or the convex portion of the armature. 3. An electromagnetic clutch according to claim 1, wherein said convex portion or said concave portion of said boss and said concave portion or said convex portion of said armature are provided with a wear-resistant coating. 4. The electromagnetic clutch according to claim 1, wherein said convex portion or said concave portion of said boss and said concave portion or said convex portion of said armature are constituted by separate parts having wear resistance. .