JP2687457B2 - Electromagnetic clutch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is provided between a driving device and a driven device,
The present invention relates to an electromagnetic clutch suitable for, for example, a compressor used in an air conditioner for a vehicle, in which transmission of rotation from the driving device to a driven device is intermittently performed.

[Conventional technology]

Conventionally, a general dry single-plate electromagnetic clutch includes a stator that generates a magnetic force, a rotor that is supported by a bearing so as to be rotated by a rotational force from a drive source, and an armature that is axially slidable by the magnetic force of the stator. (See Japanese Utility Model Publication No. 51-14998).

When the electromagnetic clutch having such a structure is mounted and used in a compressor of an air conditioner for a vehicle, for example, it is rotatably mounted on the compressor through a stator that generates magnetic force and a compressor. And a hub mounted on the compressor and having an armature slidable in the axial direction by the magnetic force of the stator. The friction surface of the armature provided facing the friction surface of the rotor is the magnetic force generated by the stator. The torque sucked by the rotor and transmitted from the drive device is transmitted to the driven side compressor.

[Problems to be solved by the invention]

In the above electromagnetic clutch, the friction surfaces of the rotor and the armature are circular flat surfaces, and the transmission torque T by this friction surface is T = μFR (where μ: friction coefficient, F: attractive force, R: average). Radius).

Here, μ is as small as 0.2 in the case of soft iron comrades,
In order to generate a high torque, a high suction force or a large average radius is required, which has been a factor that hinders downsizing of a dry single plate clutch.

In view of the above points, the present invention is to provide a dry single-plate electromagnetic clutch that can be downsized while generating high torque.

[Means for solving the problem]

According to the present invention, the above-mentioned problems can be solved by arranging the pin attached to the armature and the hole provided in the rotor to be engaged when the rotation is transmitted to the driven body. That is, the structure of the present invention as a means for solving the above-mentioned problems is a stator having an exciting coil, a rotor which is rotated by a rotational force from a drive source and has a friction surface on one side, An armature slidably attached to the rotary shaft with a predetermined gap between the friction surface and the rotor, the friction surface of the armature being moved by the excitation coil. In an electromagnetic clutch adapted to contact a friction surface to transmit the rotation of the rotor to the rotary shaft, a pin of a magnetic material biased away from the friction surface of the rotor is attached to the armature, The friction surface has a pin hole corresponding to the pin, and the pin is fitted into the pin hole when the exciting coil is actuated.

(Operation)

In the present invention having the above-mentioned structure, when the rotation from the rotor is transmitted to the rotary shaft, when the exciting coil is energized, the armature attracts and moves in the axial direction and comes into close contact with the rotor. This close contact reduces the resistance of the magnetic circuit and increases the amount of magnetic flux, so that the pin attached to the armature overcomes its urging force and is attracted to the rotor side. When the rotor is rotated and the pin hole on the rotor side is aligned with the position of the pin due to the rotation of the rotor, the pin fits into this pin hole, the armature is firmly connected to the rotor, and the rotational force from the rotor causes the pin hole on the rotor side , Is transmitted to the rotating shaft via the armature.
Therefore, a large torque can be transmitted without increasing the attraction force of the exciting coil or the radius of the friction surface, and the electromagnetic clutch can be downsized.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 and 2, 100 is a compressor housing, and 103 is a rotary shaft of the compressor. Reference numeral 1 denotes a stator housing made of a magnetic material, in which an exciting coil 2 is embedded with an epoxy resin 20. The exciting coil 2 is connected to an external power source by a lead wire (not shown). A mounting flange 1a is joined to the stator housing 1, and the stator housing 1 is fixed to the compressor housing 100 by a circlip 101 via the mounting flange 1a. 3 is a pulley 3a
Is a magnetic rotor integrally formed with the compressor and is rotatably mounted on the compressor housing 100 via a bearing 7.
The outer ring 7a of the bearing 7 is fixed to the rotor 3 by press fitting, and the inner ring 7b
Is fitted in the compressor housing 100 and fixed to the housing 100 by a circlip 102. The friction surface 3b of the rotor 3 has elongated holes 3c and 3d for magnetically cutting, a hole 3e in which a pin (described later) is inserted, and a flat portion for guiding the pin.
3f and a concave portion 3g (Fig. 3) for adjusting the magnetic flux density are provided.

The armature 4 is arranged to face the rotor friction surface 3b with a minute gap. The armature 4 is made of a magnetic material and formed in an annular shape. The armature 4 is connected to the rotary shaft 103 of the compressor by a bolt 104 via a plurality of leaf springs 6 which are spring means fixed to the armature 4 by a plurality of lippets 5. The hub 7 and the rivets 8 are fixed to each other. As shown in FIG. 4, the armature 4 is provided with three magnetic shielding oblong holes 4a and three circular holes 4b having the same center as the center line of the oblong holes 4a along the circumferential direction. This round hole
A pin 9 is fitted in 4b. The pin 9 is composed of a suction portion 9a made of a high magnetic material and a pin body 9b made of a non-magnetic material, and they are joined together by press fitting (FIG. 6).

The pin 9 is held in place by a stopper 10 and a spring 11 that biases the pin 9 away from the rotor 3. The stopper 10 is made of a non-magnetic material and is fixed to the armature 4 with a plurality of bolts 12.

When the exciting coil 2 is energized when the compressor is started, a magnetic flux is generated as shown by a broken line i in FIG. 2, and the armature 4 is immediately applied with a force to be attracted to the rotor 3. As a result, the leaf spring b elastically bends, and the armature 4 moves in the axial direction and comes into close contact with the rotor friction surface 3b of the rotor 3 by suction.

The close contact between the armature 4 and the rotor 3 reduces the resistance of the magnetic circuit and further increases the amount of magnetic flux. As a result, the magnetic flux flowing through the pin attracting portion 9a increases, and a suction force that exceeds the spring biasing force of the spring 11 that holds the pin 9 works.

Here, the pin hole 4b of the armature 4 and the pin hole of the rotor
If the positions of 3e do not match, the tip of the pin body 9b contacts the guide plane portion 3f of the rotor 3, and the pin 9 does not adhere to the armature 4. When the rotation further progresses and the pin hole 4b on the armature side matches the pin hole 3e on the rotor side, the pin body 9b
Fits into the pin hole 3e, and the pin 9 comes into close contact with the armature 4.

Then, the driving force transmitted from the rotor 3 driven by a vehicle engine (not shown) via a belt is transmitted to the compressor shaft 103 via the rotor pin hole 3e, the pin body 9b, the armature 4, the leaf spring 6, and the hub 7. .

When the operation of the compressor is stopped, the energization of the exciting coil 2 is stopped and the magnetic flux disappears. As a result, the pin 9 is separated from the armature 4 by the restoring force of the spring 11, and the armature 4 is separated from the rotor 3 so that the driving force is not transmitted.

Here, the gap between the armature 4 and the rotor 3 is about 0.5 mm, which is the minimum value in consideration of operability and vibration resistance. On the other hand, the gap between the armature 4 and the pin 9 is set to about 2 mm, which is determined from the allowable surface pressure of the pin and rotor 3 after the operation. The spring force is determined from the vibration resistance and operability of each. The spring constant of the leaf spring 6 holding the armature 4 is about 10 kg / mm, and the spring constant of the spring 11 holding the pin 9 is about 0.3 kg / mm. is there.

As shown in FIG. 5, the rotor 3 has a pin body 9b.
In order to facilitate smooth fitting into the rotor pin hole 3e, the rotor flat surface portion 3f is chamfered 3g, and as shown in FIG. 6, a radius R is provided at the tip of the pin body 9b. Flat part 3f
Is not necessarily flat. When the relative rotation difference between the rotor 3 and the armature 4 is large, the front side of the rotor pin hole 3e is raised so that it is hard to operate, or the pin body 9b is fitted early so as to avoid wear between the rotor 3 and the armature 4 It may be an inclined surface that is gentle toward the hole 3e.

Since the pin main body 9b has a smaller friction part area than the rotor 3, it is desirable that the pin body 9b be less worn than the rotor, and a high carbon steel quenching material, bearing steel, or the like is used.

Further, when the residual magnetism of the pin 9 becomes a problem, a non-magnetic stainless material, a ceramic material or the like is used.

7 and 8 show a second embodiment of the present invention, in which rubber is used as a member that allows the armature 4 to move in the axial direction, and a triangular hub 7 is used. A rubber damper 14 is attached to the outer peripheral edge of the armature 4 and is connected to the armature 4 via a holding plate 13 and a rivet 5 on the peripheral edge. Further, the stopper 10 is fixed to the armature 4 by spot welding 10a, but it can be fixed similarly by a fixing means such as a rivet or an adhesive.

9 and 10 show a third embodiment of the present invention,
The holding plate 13 on the periphery of the rubber damper 14 in the embodiment is further expanded to integrally form a stopper 13a for the pin suction portion 9a.

11 and 12 show a fourth embodiment of the present invention, in which the stopper for positioning the pin 9 is omitted. That is, the enlarged stepped portion 9c is formed at the tip of the pin body 9b, and the stepped recess where the stepped portion 9c is fitted to the armature 4 is formed.
4c is provided, and the pin 9 is prevented from being separated from the armature 4 by a certain distance or more by fitting the stepped portion 9c and the recess 4c. The pin hole 3e on the rotor 3 side is a stepped portion.
Needless to say, it should have a hole of approximately the same diameter as this to fit 9c.

〔The invention's effect〕

Since the present invention has the configuration and operation as described above,
When transmitting rotation to the driven body, the pin attached to the armature fits into the pin hole provided on the rotor side, and the engagement between the armature and rotor becomes firm, so frictional force as in the conventional The torque can be transmitted through the pin without depending only on the suction force, and thus a large torque can be transmitted. Therefore, it is not necessary to increase the size of the excitation coil or the diameter of the armature for torque transmission, and it is possible to reduce the size of the electromagnetic clutch as a whole. Therefore, when this electromagnetic clutch is applied to a vehicle, it is particularly advantageous. Will be things.

[Brief description of the drawings]

1 is a front view of the first embodiment of the present invention, FIG. 2 is a sectional view taken along the line EE of FIG. 1, FIG. 3 is a front view of the rotor as seen from the arrow B of FIG. 2, Fourth
FIG. 5 is a front view of the armature as seen from the arrow C in FIG. 2, FIG. 5 is an enlarged sectional view taken along the line D-D in FIG. 3, and FIG. 6 is an enlarged vertical sectional view of the pin in the above embodiment. 7 is a front view of the second embodiment of the present invention, FIG. 8 is a sectional view taken along the line FF of FIG. 7, and FIG. 9 is a front view of the third embodiment of the present invention.
9 is a sectional view taken along the line GG of FIG. 9, FIG. 11 is a front view of the fourth embodiment of the present invention, and FIG. 12 is a sectional view taken along the line HH of FIG. 1 ... Stator housing, 2 ... Excitation coil, 3 ... Rotor, 3b ... Rotor friction surface, 3e ... Pin hole, 4 ... Armature, 4a ... Magnetic blocking slot, 4b ... Pin round Hole, 9 ... pin, 10 ... stopper, 11 ... spring, 103 ... rotating shaft.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takemoto Takeshi 1-1, Showa-cho, Kariya city, Aichi Japan Denso Co., Ltd. (56) Reference JP-A-1-303323 (JP, A) 6815 (JP, Y1)

Claims (1)

(57) [Claims] 1. A stator having an exciting coil, a rotor rotated by a rotational force from a drive source and having a friction surface on one side, and a rotor having a friction surface facing the friction surface of the rotor. An armature slidably attached to the rotating shaft with a predetermined gap therebetween, and by operating the exciting coil, the friction surface of the armature is brought into contact with the friction surface of the rotor to rotate the rotor. In the electromagnetic clutch adapted to transmit to the rotating shaft, a pin of a magnetic material biased away from the friction surface of the rotor is attached to the armature, and a pin corresponding to the pin is attached to the friction surface of the rotor. An electromagnetic clutch, characterized in that a hole is provided so that the pin fits into the pin hole when the exciting coil is actuated.