JPH08135686A - Electromagnetic clutch - Google Patents

Abstract

PURPOSE: To form an overload torque limitter mechanism which has torque fluctuation elimination function, on an electromagnetic clutch. CONSTITUTION: Current is carried to an electromagnetic coil 7 in normal state of a compressor 4, and an armature 11 is attracted to a frictional surface 2a of a rotor 2. Torque from an engine is transmitted to a rotary shaft 14 of the compressor 4 through a pulley 1, the rotor 2, the armature 11, a pin 12 fixed to the armature 11, an elastic ring 13 made of rubber, holding pieces 18, 19, and a hub 15, for operating the compressor 4. In such a normal state the elastic ring 13 serves as a torque fluctuation eliminator. In an overload state such as locking of the compressor 4, the elastic ring 13 is elastically deformed, and slips from a clearance between the holding pieces 18 and 19, for interrupting power transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch having the function of a torque limiter in the event of an abnormality, and is suitable for driving a compressor of a refrigeration cycle of an automobile air conditioner.

[0002]

2. Description of the Related Art Conventionally, a compressor of a refrigeration cycle of an automobile air conditioner is connected to an engine via an electromagnetic clutch, and the power transmission from the engine is interrupted by the electromagnetic clutch. By the way, if the compressor has a failure such as seizure and its rotating shaft is locked, a trouble such as a belt damage of the power transmission device of the engine occurs.
Once this trouble such as belt damage occurs, engine auxiliary equipment such as the engine cooling water circulation water pump and battery charging generator will become inoperable, causing a serious situation of engine operation stop. A device for doing so is required.

In the past, in general, attention has been paid to the phenomenon that the compressor rotation speed decreases when the compressor is locked, and the decrease in the compressor rotation speed is detected by a rotation detection device to interrupt the energization of the electromagnetic clutch. ing. As a result, the power transmission to the compressor is cut off to prevent the occurrence of trouble on the engine side. Also, as another type, Japanese Patent Publication Sho 5
In Japanese Patent Laid-Open No. 8-1294, it is proposed that the electromagnetic clutch itself be provided with a mechanism that acts as a torque limiter that cuts off power transmission when the compressor is locked.

[0004]

However, in the above-mentioned conventional device, the former one requires a rotation detecting device for detecting a decrease in the number of revolutions of the compressor and an electric control device therefor, which causes a problem of cost increase. is there. Further, in the latter one in which the torque limiter mechanism when the compressor is locked is provided in the electromagnetic clutch itself, an auxiliary armature is interposed between the input hub to which the rotation from the drive source (engine etc.) is transmitted and the armature. Between the auxiliary armature and the input hub, there is provided a torque limiter mechanism including a spherical member arranged in the conical recess and a cam mechanism using a plurality of rod-shaped spring members.

Therefore, in the latter case, it is necessary to add a complicated mechanism dedicated to the torque limiter, which causes a problem that the size of the electromagnetic clutch becomes large and the cost increases. Further, since the torque limiter mechanism is composed of the cam mechanism in which the spherical body and the rod-shaped spring member are combined as described above, the cam mechanism itself cannot have the function of absorbing the torque fluctuation of the compressor. Therefore, in order to absorb the torque fluctuation of the compressor, it is necessary to separately install a mechanism for absorbing the torque fluctuation, which causes a problem of further cost increase.

The present invention has been made in view of the above points,
An object of the present invention is to provide an electromagnetic clutch which is an engagement mechanism using a rubber elastic member having a torque fluctuation absorbing action and which can also exert a torque limiter function at the time of overload.

[0007]

In order to achieve the above object, the present invention employs the following technical means. According to the first aspect of the present invention, the drive side rotation member (1, 2) that rotates by receiving the rotational force from the rotary drive source and the driven side rotation connected to the rotation shaft (14) of the driven side device (4). The member (15), the electromagnetic means (7) for generating an electromagnetic attraction force by energization, and the friction surface (2a) of the drive side rotating member (1, 2) are disposed so as to face each other, and The armature (11, 11A, 11B) attracted to the friction surface (2a) of the driving side rotation member (1, 2) by the generated electromagnetic attraction force, the driven side rotation member (15) and the armature (11, 11
A, 11B) are arranged so as to be connected to each other and elastically deformable rubber elastic members (13, 130), and a holding member (1) for holding the elastic members (13, 130).
8, 180, 19, 190), and when the rotational force is within a predetermined value, the elastic member (13, 130) causes the holding member (18, 180, 180) to move when the rotational force is within a predetermined value. 19, 190) are integrally held by the driven side rotating member (15) and the armature (11, 1).
1A, 11B) are integrally connected to each other, and at the time of overload in which the rotational force is increased to a predetermined value or more, the elastic member (1
3, 130) elastic deformation of the elastic member (1
3, 130) and the holding members (18, 180, 19, 1)
90) is released from the integral connection, and the driven side rotating member (15) and the armature (11, 11A, 1) are released.
1B) is characterized by an electromagnetic clutch configured to disconnect the connection.

According to a second aspect of the present invention, the elastic member (1) is acted upon at the time of overload in which the rotational force rises above a predetermined value.
3) The elastic member (13) separates from the holding member (18, 19) due to its own elastic deformation, and the driven side rotating member (15) and the armature (11, 11A, 11).
The electromagnetic clutch according to claim 1, wherein the electromagnetic clutch is configured to disconnect the connection with B).

According to a third aspect of the invention, in the electromagnetic clutch according to the second aspect, the armature (11, 11).
A, 11B) has a pin (12) fixed to the pin, and the elastic member (13) is fitted and fixed to the pin (12), and the holding member (18, 19) is the rotating member. It is characterized by being configured as a cup-shaped member having a gap (A, B) on both the positive side and the negative side of the rotation direction of (1, 2, 15).

According to a fourth aspect of the invention, in the electromagnetic clutch according to the second or third aspect, the elastic member (1
3) is fixed to the armature (11, 11A, 11B), and the holding member is the armature (1).
1, 11A, 11B) fixed to the first holding piece (1
8) and a second fixed to the driven side rotating member (15).
And a holding piece (19).

According to a fifth aspect of the present invention, in the electromagnetic clutch according to any one of the second to fourth aspects, the holding member (18, 19) is provided with the rotating members (1, 2,
15) is configured as a cup-shaped member having a gap (A, B) on both the positive direction side and the negative direction side of the rotation direction, and the gap of the holding member (18, 19) is the rotation direction. It is characterized in that the gap (B) on the negative side is larger than the gap (A) on the positive side in the direction.

According to a sixth aspect of the present invention, in the electromagnetic clutch according to any one of the third to fifth aspects, the holding member (18, 19) has one of the two gaps (A, B). It is characterized in that side walls (18b, 19b) having an arc shape are formed in a gap portion on the side where the elastic member (13) separates from the holding members (18, 19) during the overload.

According to a seventh aspect of the invention, in the electromagnetic clutch according to any one of the second to sixth aspects, the armature is divided into two in the radial direction.
And a second armature (11A, 11B),
This first and second armature (11A, 11B)
And the friction surface (2) of the drive side rotating member (18, 19).
It is characterized in that one of the gaps (G1, G2) with respect to a) is set to be small and the other is set to be large.

According to an eighth aspect of the present invention, in the electromagnetic clutch according to the first aspect, the elastic member (130) is
The driven side rotating member (15) and the armature (1)
1, 11A, 11B) and is formed in a substantially cylindrical shape concentric with the holding member (180, 190),
The driven side rotating member (15) and the armature (1)
1, 11A, 11B) and are formed in a substantially cylindrical shape having a diameter different from that of the elastic member (130), and the elastic member (130) and the holding member (180) having the substantially cylindrical shape. , 190) are crimped while being locked in the rotation direction, and the coupling mechanism is configured to elastically deform the elastic member (130) at the time of overload in which the rotational force rises above a predetermined value. The elastic member (13
0) The holding member (180, 190) slides on the surface, and the driven side rotating member (15) and the armature (1).
1, 11A, 11B) is configured to be cut off.

According to a ninth aspect of the invention, in the electromagnetic clutch according to the eighth aspect, the driven side rotating member (15).
And arranged concentrically with the armatures (11, 11A, 11B) and with the armatures (11, 11A, 1).
1B) a substantially cylindrical first holding piece (180)
And a substantially cylindrical second holding piece coupled to the driven side rotation member (15) and concentrically arranged on the inner peripheral side of the first holding piece (180) with a predetermined gap. (190)
From the above, the holding member is constituted, and the substantially cylindrical elastic member (130) is engaged in the rotational direction between the first holding piece (180) and the second holding piece (190). It is characterized by being crimped while being stopped.

According to a tenth aspect of the invention, in the electromagnetic clutch according to the ninth aspect, the first holding piece (18
0) and at least one of the second holding pieces (190), locking shape portions (180a, 180b, 190) for increasing the locking force in the rotational direction with the elastic member (130).
a, 190b) are formed, and the elastic member (13
0) also has a locking shape part (130) corresponding to the locking shape part.
a, 130b) are formed.

According to an eleventh aspect of the present invention, in the electromagnetic clutch according to the tenth aspect, the engaging shape portions are a plurality of convex portions (130a, 130a, which are alternately and repeatedly formed in the rotational direction).
180a, 190a) and recesses (130b, 180b, 1)
And 90b). According to a twelfth aspect of the present invention, in the electromagnetic clutch according to any one of the first to eleventh aspects, the drive side rotation member (18, 19) is rotated by receiving a rotational force from an automobile engine. It is characterized in that the driven device is a compressor (4) of a refrigerating cycle of an automobile air conditioner.

The reference numerals in parentheses of the above means indicate the correspondence with the concrete means described in the embodiments described later.

[0019]

According to the invention described in claims 1 to 12, since it has the above-mentioned technical means, the elastic member (13) is provided at the time of overload in which the rotational force from the drive source rises to a predetermined value or more. , 130) by elastic deformation of the elastic member (1
3, 130) and holding members (18, 180, 19, 19)
By canceling the integrated connection with 0), the power transmission between the drive source and the driven side device (4) can be cut off, and the torque limiter function at the time of overload can be reliably exerted. It is possible to prevent damage to various devices due to continued load operation.

Moreover, the elastic member (13, 130) made of rubber has a mechanism for exerting the torque limiter function.
And the holding member (18, 180, 19, 190) are combined to make use of the impact absorption characteristics of rubber,
The torque fluctuation of the driven device (4) such as the compressor can be absorbed well. In addition to the above function and effect, in the invention according to claim 3, the pin (12) is fixed to the armature (11, 11A, 11B), and the elastic member (13) is fitted and fixed to the pin (12). , The holding member (18, 19)
Is configured as a cup-shaped member having a gap (A, B) on both the positive direction side and the negative direction side of the rotation direction of the both rotary members, and therefore the pin (12) of the elastic member (13).
Fixing to and elastic members (13) and holding members (18, 1)
It can be easily assembled with 9).

According to the sixth aspect of the invention, the gaps (A, B) of the holding member (18, 19) made of a cup-shaped member.
Among these, since side walls (18b, 19b) having an arc shape are formed in the gap portion on the side where the elastic member (13) separates from the holding member (18, 19) during the overload, Side wall portions (18b, 19) having an arc shape
b), the elastic member (13) causes the holding member (1
8 and 19), the rubber surface of the elastic member (13) can be prevented from being damaged.

According to a seventh aspect of the present invention, the armature is divided into first and second parts in the radial direction.
Of the armatures (11A, 11B), and the gaps (G1, G2) between the first and second armatures (11A, 11B) and the friction surface (2a) of the driving side rotation member (18, 19). 1) is set to be small and the other is set to be large, so that two armatures (11A, 11B) are attracted to the friction surface (2a) in two steps with a time difference when the electromagnetic clutch is activated.

Therefore, since the starting torque can be greatly reduced as compared with the general system in which the armature is adsorbed at once, the elastic member (13) made of rubber and the holding member (1).
8, 19) and a coupling mechanism (torque limiter mechanism)
Can be set within a relatively wide range. As a result, the degree of freedom in designing the coupling mechanism (torque limiter) can be greatly expanded, and by increasing the degree of freedom in design, cost reduction of the product can be facilitated and reliability can be improved at the same time.

Further, in the invention described in claims 8 to 11, the driven side rotating member (15) and the armature (11,
11A, 11B) and a substantially cylindrical elastic member (130) arranged concentrically with the holding member (18).
0, 190) and the substantially cylindrical elastic member (13
0) and the holding members (180, 190) are crimped while being locked in the rotational direction to constitute the connecting mechanism. Therefore, the armature (11, 11A, 11B) according to the invention of claim 3. The structure of the connecting mechanism can be simplified and the cost can be reduced as compared with the case where the pin (12) is fixed.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) In FIGS. 1 and 2, reference numeral 1 denotes a driving pulley, which is rotated by receiving a rotational force from an automobile engine via a belt (not shown). This pulley 1 is a pulley portion 1a having a multiple V groove with which a multiple V belt is engaged.
Are integrally formed and are made of iron-based metal.

Reference numeral 2 denotes a drive side rotor formed in a double ring shape having a U-shaped cross section, which is made of a ferrous metal (ferromagnetic material) and is integrally formed with the pulley 1 by a joining means such as welding. It is joined. A bearing 3 is arranged on the inner peripheral portion of the rotor 2, and the rotor 3 is rotatably supported by the bearing 3 on the cylindrical protrusion 5 a of the front housing 5 of the compressor 4. Here, the compressor 4 is for compressing a refrigerant in a refrigerating cycle of an automobile air conditioner, and may be any known swash plate type, vane type, scroll type or the like.

A fixed magnetic pole member 6 has a U-shaped cross section.
It is made of iron-based metal (ferromagnetic material) in the shape of a heavy ring. Inside the fixed magnetic pole member 6, an electromagnetic coil 7 is insulated and fixed by a resin member 8. Further, the fixed magnetic pole member 6 is fixed to the front housing 5 of the compressor 4 by a stay 9 formed of a ferrous metal in a ring-shaped flat plate shape and a circlip 10 for fixing the stay.

The friction surface 2 extending in the radial direction of the rotor 2
In a, arc-shaped magnetic blocking grooves 2b, 2c extending in the circumferential direction are provided.
And a magnetic cutoff groove 2b radially outwardly formed.
A friction material 2d is arranged at the position of (1) to improve the transmission torque. Reference numeral 11 denotes an armature arranged so as to face the friction surface 2a of the rotor 2, and is formed of a ferrous metal (ferromagnetic material) in the shape of a ring-shaped flat plate. The armature 11 has a friction surface 2 of the rotor 2 when the electromagnetic coil 7 is not energized.
It is designed to be held at a position separated from a by a predetermined minute distance.

Reference numeral 12 is a pin made of an iron-based metal, which is fixed by caulking to holes 11b formed at a plurality of positions (three positions in this example) at the intermediate position between the magnetic blocking grooves 11a of the armature 11. An elastic ring body 13 made of rubber is fitted and fixed to the pin 12. As shown in FIG. 2, the plurality of elastic ring bodies 13 and the pins 12 are arranged on the same circumference X around the center of the armature 11.

As the material of the elastic ring body 13, rubber is used which exhibits excellent characteristics in terms of torque transmission and absorption of torque fluctuations in the operating environment temperature range (-30 ° C to 120 °) of the automobile. It is preferable to use rubber such as chlorinated butyl rubber, acrylonitrile butadiene rubber, and ethylene propylene rubber. Reference numeral 14 is a rotary shaft of the compressor 4, and 15 is a hub, which is made of ferrous metal and is formed into a cylindrical shape having a flange portion 15a. This hub 1
Reference numeral 5 is screwed and fixed to the rotary shaft 14 with bolts 16 and the like.

That is, a screw hole 14a is formed in the central portion of the rotary shaft 14, and the rotary shaft 14 has a spline 14b on the outer peripheral portion thereof. It is fitted with a rotation stopper.
Then, by screwing the external thread portion of the bolt 16 into the screw hole 14a, the annular protrusion 15b of the inner peripheral portion of the hub 15 is clamped between the distal end of the rotary shaft 14 and the axial dimension adjusting shim 17. It is supposed to do. As a result, the hub 15 and the rotary shaft 14 are integrally connected.

Reference numerals 18 and 19 are first and second holding pieces that form a holding member for the elastic ring body 13, and are made of iron-based metal (for example, low carbon steel SPCC) and have a cross section (see FIG. 1) of a substantially J shape. It is formed into a shape. The holding pieces 18, 19 are arranged at equal intervals (three in this example) on the same circumference on the inner circumference side or the outer circumference side of the elastic ring body 13 to form a storage space for the elastic ring body 13. To form a cup-shaped holding member.

The first member located on the outer peripheral side of the elastic ring body 13
The holding piece 18 of the elastic armature 11 is attached to the armature 11.
The second holding pieces 19 located on the inner peripheral side of 3 are integrally joined to the flange portion 15a of the hub 15 by joining means such as welding. The holding pieces 18 and 19 are provided with gaps A and B in both the positive direction and the negative direction with respect to the rotation direction R of the armature 11, that is, the elastic ring body 13.

The gap A in the positive direction of rotation is the elastic ring body 1.
3 is set to be smaller than the outer diameter of the elastic ring body 13 by a predetermined amount, while the gap B in the negative direction of the rotation is set to be larger than the outer diameter of the elastic ring body 13 by a predetermined amount. Therefore, the elastic ring body 13
With respect to the rotation direction R, it can smoothly enter into the negative gap B on the inlet side, while the positive gap A on the outlet side is prevented from moving in the rotational direction R, which results in elasticity. The ring body 13 is integrally held by the holding pieces 18 and 19.

FIG. 3 shows an auxiliary machine drive system for an automobile engine. Reference numeral 20 is a crank pulley of the automobile engine. The rotation of the crank pulley 20 is passed through a belt 21 to a pulley 1 of an electromagnetic clutch for driving a compressor. It is designed to be transmitted to. Reference numeral 22 is a driving pulley of a water pump for circulating cooling water of an engine cooling device, 23 is a driving pulley of a battery charging generator (alternator), and 24 is a driving pulley of a hydraulic pump of a power steering device. The belts 15 to 24 also rotate together with the compressor driving pulley 1 by receiving a rotational force from the belt 15.

Reference numerals 25, 26 and 27 are idle pulleys for giving a predetermined tension to the belt 15. Next, the operation of the first embodiment having the above structure will be described. First, the normal operation of the compressor 4 will be described. The rotation of the crank pulley 20 of the automobile engine is transmitted to the pulley 1 by the belt 21, and the rotor 2 is always rotating integrally with the pulley 1.

In the above state, when the electromagnetic coil 7 is energized in order to operate the automobile air conditioner, a magnetic flux is passed from the fixed magnetic pole member 6 to the fixed magnetic pole member 6 via the rotor 2 and the armature 11. Flowing. As a result, a magnetic attraction force is generated between the friction surface 2a of the rotor 2 and the armature 11, so that the armature 11 resists the axial elastic force of the elastic ring body 13 (force to the left in FIG. 1). The friction surface 2a of the rotor 2 is attracted and adsorbed.

As a result, the rotor 2 and the armature 11 rotate together, and the pin 12 and the elastic ring body 13 also rotate together. At this time, since the outer diameter of the elastic ring body 13 is larger than the gap A in the positive direction of rotation of the cup-shaped holding pieces 18, 19, the elastic ring body 13 is held in the holding members 18, 19. . Therefore, the elastic ring body 13 and the holding pieces 18 and 19 are integrally connected in the rotation direction R, so that the rotation of the pulley 1 is transmitted to the rotation shaft 14 of the compressor 4 via the hub 15. The compressor 4 operates.

Here, during normal operation of the compressor 4, the elastic ring body 13 made of rubber absorbs the torsional vibration due to the operation of the compressor 4, so that a load torque of about 20 Nm is usually applied to the elastic ring body 13. However, at that time, the elastic ring body 13 only slightly deforms at the above-mentioned load torque. The size of the gap A in the positive direction of rotation is set so that the elastic ring body 13 is held in the holding pieces 18 and 19 with this small deformation. , 19 outside. FIG. 4 (a) shows a small deformation state of the elastic ring body 13 in this load torque applied state. The broken line shows the initial state before the load torque is applied to the elastic ring body 13.

Therefore, there is no problem in the power transmission from the drive pulley 1 to the rotary shaft 14 of the compressor 4. Moreover, the compressor 4
By interposing the elastic ring body 13 made of rubber in the power transmission system to the power transmission system, the effect of absorbing the torque fluctuation during the normal operation of the compressor 4 can be exhibited well. FIG. 5 shows a case I of the electromagnetic clutch according to the present invention using the elastic ring body 13 made of rubber.
And the case II of the electromagnetic clutch in which the rubber elastic ring body 13 of the related art is not used are compared to show the torque fluctuation absorbing effect. The horizontal axis of FIG. 5 is the rotation speed of the compressor 4, and the vertical axis is the one-sided amplitude torque with respect to the average value of the load torque fluctuation width generated on the compressor rotation shaft (in other words, 1 / of the load torque fluctuation width).
2).

As can be seen from FIG. 5, in the case I according to the present invention, the peak of the torque shifts to a low rotational speed range as compared with the prior art II, and the peak value can be greatly reduced.
The effect of reducing the vibration of the compressor can be exhibited. On the other hand, when the compressor 4 is locked, an excessive load torque is applied to the elastic ring body 1.
Since the elastic ring body 13 undergoes a large deformation as shown in FIG. 4 (b), it gradually slips out of the gap A between the holding pieces 18, 19 and finally as shown in FIG. 4 (c). To the outside of the holding pieces 18, 19 and the elastic ring body 13
The connection between the holding pieces 18 and 19 is blocked.

However, in the rotating direction of the elastic ring body 13, the following holding pieces 18, 19 are arranged at regular intervals (120 in this example).
The elastic ring body 13
Moves towards the next holding piece 18, 19. here,
Since the gap B in the negative direction of rotation (inlet side) is set to be larger than the gap A in the positive direction of rotation (outlet side), the elastic ring body 13 can easily enter the holding pieces 18, 19. Become.

The movement of the elastic ring body 13 is continued until it is worn or damaged. Therefore, when the compressor 4 temporarily locks due to a slight cause, the elastic ring body 13 and the holding pieces 18, 19 can be automatically returned to the normal coupling state before the elastic ring body 13 is damaged. , The compressor 4 returns to the normal operation state. On the other hand, when the compressor 4 is continuously locked due to a serious failure such as seizure, the elastic ring body 13 is damaged and the power transmission to the compressor 4 is completely cut off. Therefore, in the accessory drive system for the engine shown in FIG. 3, it is possible to prevent serious damage such as damage to the belt 21 and inoperability of other accessories (22, 23, 24) other than the compressor. (Second Embodiment) As shown in FIG. 6, of the holding pieces 18, 19 of the elastic ring body 13, side wall portions having arc portions (corner R) 18a, 19a on the side of the gap A in the positive direction of rotation. 18
b and 19b are formed. These side walls 18b, 19b
By providing the circular arc portions (corner R) 18a and 19a on the elastic ring body 13 when the elastic ring body 13 slips out of the gap A, the elastic ring body 13 moves smoothly, and the side wall portion 1 is provided.
Since 8b and 19b can be elastically deformed outward from each other, the elastic ring body 13 is less likely to be damaged.

Since the side wall portions 18b and 19b can be elastically deformed outwardly, the degree of freedom in designing the dimension of the clearance A is increased. (Third Embodiment) As shown in FIGS. 7 to 9, in this embodiment, the armature 11 is divided into two in the radial direction, and first (outer peripheral side) and second (inner peripheral side) armatures 11A and 11B. Is provided, the gap G1 between the first armature 11A on the outer peripheral side and the friction surface 2a of the rotor 2 is small (for example, 0.3 mm), and the second armature 11B on the inner peripheral side and the friction surface 2a of the rotor 2 are The gap G2 is set to be large (for example, 0.7 mm).

Further, the rubber elastic body 13 is shown in FIG.
As shown in FIG. 5, the shape is formed to be elongated in the radial direction, and the inner and outer peripheral portions thereof have arcuate portions. And
The holding piece 18 located on the outer peripheral side of the elastic body 13 is joined to the first armature 11A to hold the holding piece 1 on the inner peripheral side of the elastic body 13.
9 is joined to the flange portion 15a of the hub 15. The pin 12 is arranged at a position closer to the inner peripheral side than the central portion in the radial length of the rubber elastic body 13, and the shape of the elastic body 13 is preliminarily radiused from the pin insertion hole as shown in FIGS. By forming a shape in which the outer side in the direction is bent toward the friction surface 2a of the rotor 2, the magnitude relationship between the gaps G1 and G2 is set.

Further, as shown in FIGS. 8 and 9, the inner peripheral portion of the second armature 11B is attached to the elastic body 13 by the pin 12 while being in contact with the outer peripheral end portion of the flange portion 15a of the hub 15. There is. According to the third embodiment, the electromagnetic coil 7 is energized and the first and second armatures 11A and 11A are provided.
When an electromagnetic attraction force is generated between B and the friction surface 2a of the rotor 2, the first armature 11 having the small gap G1 is first adsorbed to the friction surface 2a of the rotor 2 and torque is transmitted. It

Then, after a lapse of some time, the second armature 11B having a large gap G2 is attracted to the friction surface 2a of the rotor 2, so that both armatures 11A, 1A,
Torque is transmitted by adsorption of 1B. in this way,
When the electromagnetic clutch is activated, the two armatures 11A, 1
1B is adsorbed in two stages with a slight time difference, and the amount of transmission torque increases in stages, so compared to the case where torque transmission suddenly rises once at the time of startup, which is generally done in the past, the starting torque is increased. Can be significantly reduced.

Explaining in more detail with a numerical example, when the conventional starting torque rapidly increases at one time, the starting torque increases to about 45 Nm. On the other hand, in the engine power transmission system shown in FIG. 3, since the slip generation torque of the belt 21 is usually about 70 Nm, the operation of the coupling mechanism (torque limiter mechanism) including the elastic body 13 made of rubber and the holding pieces 18, 19. The torque (operating torque when the torque transmission is cut off) must be set within a relatively narrow range between 45 and 70 Nm.

On the contrary, according to the third embodiment, since the two-stage torque transmission by the two armatures 11A and 11B is adopted at the time of starting the electromagnetic clutch, the starting torque can be reduced to about 30 Nm. As a result, the settable range of the operating torque can be expanded, so that the degree of freedom in designing the coupling mechanism (torque limiter) can be greatly expanded.
This expansion of the degree of freedom in design facilitates cost reduction of the product and at the same time improves reliability.

In the third embodiment, the gaps G1 and G are
The same effect can be exhibited even if the gap G1 of the first armature 11A on the outer peripheral side is large and the gap G2 of the second armature 11B on the inner peripheral side is small, contrary to the above description. . In each of the above-described first to third embodiments, the elastic body 13 and the three holding pieces 18 and 19 are provided in each three pieces, but this number is merely an example and may be increased or decreased as necessary. Of course.

Alternatively, the first and second holding pieces 18 and 19 may be integrally formed of a metal plate such as iron and integrally joined to the flange portion 15a of the hub 15. Further, instead of using the elastic ring body 13, rubber-made elastic members having various shapes such as a rectangular shape and a disk shape can be used. In this case, the elastic member may be directly bonded and fixed to the armatures 11, 11A, 11B side without using the pin.

Further, although the holding pieces 18 and 19 are formed in the cup-like shape arranged on both inner and outer peripheral sides of the elastic body 13 in the above-mentioned first to third embodiments, the holding pieces 18 and 19 are not limited to this shape. Alternatively, even if the holding pieces 18 and 19 are provided only on the hub 15 side, the functions of the torque transmission and the torque limiter can be exhibited. (Fourth Embodiment) FIGS. 10 to 12 show a fourth embodiment in which a substantially cylindrical first holding piece 180 is arranged concentrically with the armature 11 and the hub 15. The first holding piece 180 is made of aluminum (for example, A5052,
A6061) and the like are formed by pressing a non-magnetic plate material, and the cylindrical portion has a plurality of convex portions 180a and concave portions 18 that are alternately and repeatedly formed in the rotational direction.
0b and a locking shape portion are formed.

Further, an inner circumferential bent portion 180c bent toward the inner circumferential side is formed on one end side in the axial direction of the cylindrical portion of the first holding piece 180 (left side in FIG. 11), and the other end side in the axial direction ( On the right side of FIG. 11, an outer peripheral bent portion 180d bent to the outer peripheral side is formed. Then, the outer peripheral bent portion 180d of the first holding piece 180 has the armature 11
Is connected to the armature 11 by a plurality of rivets 11c that are integrally formed by stamping.

On the inner peripheral side of the first holding piece 180, the second holding piece 19 which is concentrically and substantially cylindrical is formed at a predetermined interval.
0 is arranged. The second holding piece 190 is also formed by pressing a nonmagnetic plate material such as aluminum (for example, A5052, A6061 etc.), and is repeatedly formed in the cylindrical portion alternately in the rotational direction. Further, a locking shape portion including a plurality of convex portions 190a and concave portions 190b is formed.

Further, an inner circumferential bent portion 190c bent toward the inner circumferential side is formed on one end side (the left side in FIG. 11) in the axial direction of the cylindrical portion of the second holding piece 190, and the other end side in the axial direction ( On the right side of FIG. 11, an outer peripheral bent portion 190d bent to the outer peripheral side is formed. The inner peripheral bent portion 190c of the second holding piece 190 is joined to the hub 15 by a plurality of rivets 15c integrally formed on the flange portion 15a of the hub 15.

Incidentally, the first and second holding pieces 180, 190
Is preferably formed of a non-magnetic material such as aluminum, but can be formed of a magnetic material such as cold rolled steel plate (SPCC). The elastic member 130 of this example is formed of rubber into a substantially cylindrical shape as shown in FIG.
The elastic member 130 also includes the first and second holding pieces 180, 1
A locking shape portion corresponding to the locking shape portion 90 is formed. That is, on the cylindrical circumferential surface of the elastic member 130,
A plurality of convex portions 130 that are alternately and repeatedly formed in the rotation direction.
A locking shape portion including a and a recess 130b is formed.

Since the thickness of the elastic member 130 in the radial direction is set to be slightly larger than the distance between the first and second holding pieces 180 and 190, the elastic member 130 has the first and second holding pieces. It is inserted between 180 and 190 so as to be crimped. In this fitted state, as shown in FIG. 10, the plurality of protrusions 130a and the recesses 130b of the elastic member 130 and the plurality of protrusions 180 of the first and second holding pieces 180, 190.
Since a, 190a and the recesses 180b, 190b are fitted and locked with each other, the locking force in the rotational direction between the elastic member 130 and the first and second holding pieces 180, 190 is increased. be able to.

In FIG. 10, the elastic member 130 is hatched to clearly show its shape. In addition, the inner peripheral bent portion 1 of the first holding piece 180
80c and the outer peripheral bent portion 190d of the second holding piece 190
Thus, both ends of the elastic member 130 in the axial direction are pressed to prevent the elastic member 130 from moving in the axial direction.

With the above configuration, the first and second holding pieces 1
Between 80 and 190 (in other words, between the armature 11 and the hub 15) can be integrally connected via the elastic member 130. Therefore, during normal operation of the compressor 4, the rotation of the armature 11 attracted to the friction surface 2a of the rotor 2 due to the energization of the electromagnetic coil 7 causes the rotation of the first holding piece 180,
The rotary shaft 14 of the compressor 4 can be rotated by being transmitted to the hub 15 via the elastic member 130 and the second holding piece 190, and the elastic member 130 serves to absorb the torque fluctuation of the compressor 4. be able to.

On the other hand, when the compressor 4 is locked, an excessive load torque is applied to the connecting mechanism composed of the first holding piece 180, the elastic member 130, and the second holding piece 190.
The elastic member 130 elastically deforms, and the locked state between the inner peripheral surface of the first holding piece 180 and the outer peripheral surface of the elastic member 130 on which the driving force from the engine acts is released. As a result,
The inner peripheral surface of the first holding piece 180 slips on the outer peripheral surface of the elastic member 130, and the first holding piece 180 and the elastic member 13
Since the connection state with 0 is cut off, the power transmission to the compressor 4 is cut off.

In the fourth embodiment, the fixed magnetic pole member 6 and the stay 9 are integrally formed of iron-based metal (ferromagnetic material). Further, a lead wire holding portion 8 a for holding the lead wire of the electromagnetic coil 7 is integrally formed on the resin member 8 that insulates and fixes the electromagnetic coil 7 to the fixed magnetic pole member 6. (Fifth Embodiment) FIG. 13 shows a fifth embodiment in which the shape of the elastic member 130 in the fourth embodiment is modified, and the escape groove 130 is provided at an intermediate position of the convex portion 130a of the elastic member 130.
C is provided to facilitate elastic deformation of the protrusion 130a of the elastic member 130 when the compressor 4 is overloaded, such as when the compressor 4 is locked.

By selecting the size and shape of the escape groove 130C, the operating torque for interrupting the torque transmission can be easily adjusted. In the fourth and fifth embodiments, the first,
The elastic member 130 is fitted between the second holding pieces 180 and 190 and pressure-bonded, but the elastic member 130 is pressure-bonded to only one of the first and second holding pieces 180 and 190. You may make it adhere to the other side. In this case, the convex portion 130a and the concave portion 130b are provided only on the surface of the elastic member 130 on which pressure is applied, and the surface of the elastic member 130 on the side of adhesion may have a circular shape with no irregularities. Similarly, of the first and second holding pieces 180 and 190, the holding piece on the side to be bonded may have a circular shape having no uneven portion.

Further, in the above fourth and fifth embodiments,
Only one of the first and second holding pieces 180 and 190 may be provided and the other may be omitted. For example, the first
Only the holding piece 180 is provided, the second holding piece 190 is abolished, and the elastic member 130 is pressure-bonded to the first holding piece 180.
The two members 130 and 180 may be connected to each other, and the elastic member 130 may be directly bonded to the flange portion 15 a of the hub 15.

[Brief description of drawings]

FIG. 1 is a partially cutaway half sectional view of a first embodiment of the present invention.

FIG. 2 is a front view of a first embodiment in which a main part of FIG. 1 is shown in a sectional view, showing a state before the bolt 16 is assembled.

FIG. 3 is an accessory drive system diagram of an automobile engine to which the first embodiment is applied.

FIG. 4 is an enlarged view of an essential part showing the operation behavior of the elastic ring body in the first embodiment.

FIG. 5 is a characteristic diagram showing a torque fluctuation absorbing effect according to the present invention.

FIG. 6 is a cross-sectional front view of essential parts showing a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of essential parts of a third embodiment of the present invention.

FIG. 8 is a half sectional view of a third embodiment of the present invention.

9 is an enlarged cross-sectional view of the main parts of FIG.

FIG. 10 is a front view of the fourth embodiment of the present invention.

11 is a cross-sectional view taken along line CC of FIG.

FIG. 12 is a front view of a single elastic member according to a fourth embodiment.

FIG. 13 is a front view of a single elastic member showing a fifth embodiment of the present invention.

[Explanation of symbols]

1, 2 ... Pulley, rotor (driving side rotating member), 4 ... compressor, 7 ... electromagnetic coil (electromagnetic means), 11, 11A, 11
B ... Armature, 12 ... Pin, 13 ... Elastic ring body (elastic member), 130 ... Cylindrical elastic member, 14 ... Rotating shaft, 1
5 ... Hub (driven side rotating member), 18, 19 ... Holding piece, 1
8b, 19b ... Side wall part, 180, 190 ... Holding piece.

Claims (12)

[Claims] 1. A drive-side rotating member that receives a rotational force from a rotary drive source to rotate, a driven-side rotating member that is connected to a rotation shaft of a driven-side device, and an electromagnetic means that generates an electromagnetic attraction force by energization. An armature that is disposed so as to face the friction surface of the drive-side rotating member and that is attracted to the friction surface of the drive-side rotating member by the electromagnetic attraction force generated by the electromagnetic means, and the driven-side rotating member and the armature. The elastic member is made of rubber and is elastically deformable, and a connecting mechanism including a holding member that holds the elastic member. The connecting mechanism is configured so that the rotational force is within a predetermined value. In some cases, the elastic member is integrally held by the holding member to integrally connect the driven-side rotating member and the armature, and when the rotational force is increased to a predetermined value or more, the elastic member is Member itself The elastic deformation of the body releases the integral connection relationship between the elastic member and the holding member, and disconnects the connection between the driven-side rotation member and the armature. An electromagnetic clutch to do. 2. At the time of overload in which the rotational force rises to a predetermined value or more, the elastic member separates from the holding member due to elastic deformation of the elastic member itself so that the driven-side rotating member and the armature are separated from each other. The electromagnetic clutch according to claim 1, wherein the electromagnetic clutch is configured to disconnect the connection. 3. A pin fixed to the armature, wherein the elastic member is fitted and fixed to the pin, and the holding member is a positive direction side and a negative direction side of the rotation directions of the both rotary members. The electromagnetic clutch according to claim 2, wherein the electromagnetic clutch is configured as a cup-shaped member having a gap on both sides. 4. The elastic member is fixed to the armature, and the holding member is a first holding piece fixed to the armature and a second holding piece fixed to the driven side rotating member. The electromagnetic clutch according to claim 2, wherein the electromagnetic clutch is formed of 5. The holding member is configured as a cup-shaped member having a gap on both the positive direction side and the negative direction side of the rotation direction of the both rotary members, and the gap of the holding member is 5. The gap on the negative side is larger than the gap on the positive side in the rotation direction, and the gap on the negative side is larger.
One electromagnetic clutch. 6. The holding member includes:
6. A side wall portion having an arc shape is formed in a gap portion on the side where the elastic member separates from the holding member when the overload occurs.
One electromagnetic clutch. 7. The armature comprises first and second armatures that are divided into two in the radial direction, and a gap between the first and second armatures and a friction surface of the drive-side rotating member. 7. One of the two is set to be small and the other is set to be large.
The electromagnetic clutch according to any one of 1. 8. The elastic member is formed in a substantially cylindrical shape concentrically arranged with the driven-side rotating member and the armature, and the holding member is concentric with the driven-side rotating member and the armature. And is formed in a substantially cylindrical shape having a diameter different from that of the elastic member. A mechanism is configured, and at the time of overload in which the rotational force rises above a predetermined value, the elastic member is elastically deformed and the holding member slides on the surface of the elastic member, so that the driven side rotating member and the armature are The electromagnetic clutch according to claim 1, wherein the electromagnetic clutch is configured to disconnect the connection between the electromagnetic clutch and the electromagnetic clutch. 9. A substantially cylindrical first holding piece that is arranged concentrically with the driven side rotating member and the armature and that is connected to the armature; and a first holding piece that is connected to the driven side rotating member. The holding member is composed of a substantially cylindrical second holding piece that is concentrically arranged on the inner peripheral side of the first holding piece with a predetermined gap therebetween, and the substantially cylindrical elastic member is The first holding piece and the second
9. The electromagnetic clutch according to claim 8, wherein the electromagnetic clutch is crimped while being locked in a rotating direction between the holding piece and the holding piece. 10. A locking shape portion is formed on at least one of the first holding piece and the second holding piece to enhance a locking force in a rotation direction with the elastic member, and The electromagnetic clutch according to claim 9, wherein the elastic member is also formed with a locking shape portion corresponding to the locking shape portion. 11. The electromagnetic clutch according to claim 10, wherein the locking shape portion includes a plurality of convex portions and concave portions that are alternately and repeatedly formed in the rotation direction. 12. The drive-side rotating member is configured to rotate by receiving a rotational force from an automobile engine, and the driven-side device is a compressor of a refrigeration cycle of an automobile air conditioner. The electromagnetic clutch according to any one of claims 1 to 11.