JP2870004B2 - Electromagnetic clutch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic clutch that transmits and disconnects rotational power.

[Related Art] As an example of an electromagnetic clutch, an electromagnetic clutch used in a refrigerant compressor of a refrigeration cycle used in an automobile will be described.

 FIG. 9 shows an example of a conventional electromagnetic clutch.

The exciting coil 101 of the electromagnetic clutch 100 has an annular shape. The pulley 102 (first rotating body) includes an outer magnetic path member 103 and an inner magnetic path member 104 that sandwich the exciting coil 101 from the inner circumference and the outer circumference.
And a first friction material 105 connecting the outer magnetic path member 103 and the inner magnetic path member 104. The pulley 102 is rotatably supported by a rolling bearing 106 disposed inside the inner peripheral magnetic path member 104. The rolling bearing 106 is mounted on the refrigerant compressor 1
Inner housing 109 fixed to housing 108 of 07
(Components of the support member). The inner housing 109 also supports a stator housing 110 (a component of a support member) that supports the exciting coil 101.

Then, when the excitation coil 101 is energized, a magnetic path is formed in the magnetic material around the excitation coil 101 by the magnetic force generated by the excitation coil 101 as shown by a broken line C in the figure. Then, the second friction material 111 (a component of the second rotating body) is attracted to the pulley 102, and the first friction material 10 of the pulley 102 is
5 and the second friction material 111 are frictionally engaged. As a result, the pulley
The rotational power of the engine transmitted to 102 is transmitted to drive shaft 112 of refrigerant compressor 107.

[Problem to be Solved by the Invention] A refrigerant compressor 107 is generally installed in an engine room of an automobile, and performs suction, compression, and discharge of refrigerant by rotational power transmitted through a belt and an electromagnetic clutch 100. .

In recent years, refrigerant compressors have been
There is a request to downsize 107. When the size of the refrigerant compressor 107 is reduced, the capacity of the refrigerant compressor 107 is reduced. Refrigerant compressor 1
Even if the capacity of 07 becomes small, in order to generate the same capacity as the conventional one, the rotational speed of the refrigerant compressor 107 may be increased.

Therefore, it is conceivable to reduce the diameter of the pulley 102 and increase the rotation speed of the refrigerant compressor 107.

However, when the diameter of the pulley 102 is reduced, the thickness of the magnetic material on the inner and outer circumferences of the exciting coil 101 is reduced. Then, the magnetic resistance increases, and the amount of magnetic flux generated when the excitation coil 101 is energized decreases. In addition, there is a problem that an engagement torque required for engaging the first friction material 105 and the second friction material 111 cannot be obtained.

That is, when the diameter of the electromagnetic clutch 100 is reduced, there is a problem that the engagement torque decreases due to an increase in magnetic resistance.

[Purpose] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic clutch capable of suppressing a decrease in engagement torque and reducing the diameter.

[Means for solving the problem]

In order to achieve the above object, the present invention employs the following technical means.

The electromagnetic clutch is an annular exciting coil that generates a magnetic force when energized, and is disposed on the inner circumference of the exciting coil, has a substantially cylindrical shape, and has an inner circumference made of a magnetic material supported by a bearing. A first rotating body including a magnetic path member and a first friction material having a ring shape and made of a magnetic material; and a first rotating member disposed opposite to the first friction material, having a ring shape, and having friction with the first friction material. A rotatable second rotator provided with a second friction material made of a magnetic material capable of being engaged, and the exciting coil supported on the inner periphery of the bearing and on a side of the second friction material opposite to the bearing. And a support member made of a magnetic material for supporting the above.

The support member is fixed with a bypass magnetic path material made of a magnetic material that forms a minute gap between the bearing and the inner peripheral surface of the first rotating body on the second friction material side with respect to the bearing. .

[Action]

Next, an operation when the excitation coil having the above configuration is energized will be described.

When the excitation coil is energized, the excitation coil generates a magnetic force. With this magnetic force, a magnetic path passing through the inner peripheral magnetic path member on the outer periphery of the bearing is formed, and a magnetic path passing through the support member on the inner peripheral side of the bearing (the magnetic path passing through the support member, the bypass magnetic path member, and the first rotor) Path) is formed.

〔The invention's effect〕

Even if the inner circumferential magnetic path member is provided thinner to reduce the diameter of the electromagnetic clutch, magnetic paths are formed in the inner circumferential magnetic path member on the outer periphery of the bearing and the support member on the inner circumference of the bearing, respectively. Can be suppressed, and as a result, the diameter of the electromagnetic clutch can be reduced without weakening the engagement torque.

Next, an embodiment in which the electromagnetic clutch of the present invention is applied to a refrigerant compressor of a vehicle refrigeration cycle will be described.

1 to 4 show a first embodiment of the present invention. FIG. 1 is a side sectional view of an electromagnetic clutch attached to a refrigerant compressor. FIG. 2 is a front view of the electromagnetic clutch.

When rotational power is transmitted to the drive shaft 2, the refrigerant compressor 1 has a well-known structure that sucks, compresses, and discharges the refrigerant by the rotational power. The refrigerant compressor 1 of the present embodiment is a conventional refrigerant compressor. It has a smaller volume than the machine 1.

An electromagnetic clutch 3 for transmitting or interrupting the rotation output of an engine (not shown) is mounted on a drive shaft 2 of the refrigerant compressor 1. The electromagnetic clutch 3 is roughly composed of a support member 5 that supports the exciting coil 4, a first rotating body 6, and a second rotating body 7.

First, the excitation coil 4 and the support member 5 will be described.

The exciting coil 4 is a known coil formed by winding a conductive wire coated with an insulating film around a resin bobbin 8, and generates a magnetic force when energized. The exciting coil 4 is molded and fixed around the support member 5 using a resin 9 such as an epoxy resin.

The support member 5 is fixed to the housing 10 of the refrigerant compressor 1. In this embodiment, the support member 5 is configured by combining a stator housing 11 and an inner housing 12.

The stator housing 11 has an annular shape and is press-fitted and fixed around the inner housing 12. The material of the stator housing 11 is made of a magnetic material such as iron. The stator housing 11 is disposed close to the inner periphery of the exciting coil 4 and the rear of the exciting coil 4 (the right side in FIG. 1, the refrigerant compressor 1 side).

The inner housing 12 is a housing of the refrigerant compressor 1.
It is made of a magnetic material such as iron fixed to the bolts 10 via bolts 13. This inner housing 12 has an annular shape,
A cylinder portion 14 that covers the drive shaft 2 is provided on the inner periphery. A shaft seal 15 is mounted on the inner periphery of the cylindrical portion 14 so as to prevent the lubricating oil and the refrigerant on the refrigerant compressor 1 side from leaking to the second rotating body 7 side.

 Next, the first rotating body 6 will be described.

The first rotating body 6 of the present embodiment is a pulley around which a multi-stage V-belt (not shown) is wound, and is rotated by the rotational power of the engine transmitted via the multi-stage V-belt.
The material of the first rotating body 6 is made of a magnetic material such as iron.
The shape of the first rotating body 6 has an annular shape with a U-shaped cross section that covers the exciting coil 4 from the front. Specifically, a cylindrical outer magnetic path member 16 covering the outer circumference of the exciting coil 4, a cylindrical inner magnetic path member 17 disposed on the inner circumference of the exciting coil 4, and the outer magnetic path member 16 and the inner circumferential The first friction member 18 is connected to the magnetic path member 17.

A multistage groove 19 around which the multistage V-belt is stretched is formed around the outer peripheral magnetic path member 16. The portion where the multi-stage V-belt is stretched may be formed separately and fixed to the first friction material 18.

The inner circumferential magnetic path member 17 of the present embodiment is provided with a smaller thickness (radial thickness) as compared with the related art. And the first
The rotating body 6 is provided with a smaller diameter dimension by the thinner inner circumferential magnetic path member 17. An outer ring 20a of a rolling bearing 20 for rotatably supporting the first friction member 18 is press-fitted and fixed to the inner periphery of the inner magnetic path member 17. The inner ring 20b of the rolling bearing 20 is mounted on the outer periphery of the cylindrical portion 14 of the support member 5, and is fixed to the outer periphery of the cylindrical portion 14 by a bypass magnetic path member 21 described below.

The front surface of the first friction material 18 is a ring-shaped and smooth first friction surface.
It is 22. Further, the first friction material 18 has a first magnetic blocking slot 23 formed on the inner circumference side and the outer circumference side over substantially the entire circumference.

Next, the bypass magnetic path member that has fixed the rolling bearing 20
21 will be described with reference to FIGS. 3 and 4. FIG.

The bypass magnetic path member 21 includes a cylindrical boss 24. A male screw 24a is formed around the boss 24.
The male screw 24a is screwed into a female screw 14a (see FIG. 1) formed on the inner periphery of the distal end of the cylindrical portion 14 of the support member 5.

The bypass magnetic path member 21 includes a large-diameter large-diameter portion 25 via a step 25a. When the bypass magnetic path member 21 is fixed to the support member 5 by screwing, the step 25a of the large-diameter portion 25 comes into contact with the inner ring 20b (see FIG. 1) of the rolling bearing 20 to fix the rolling bearing 20. Things.

Around the large diameter portion 25, a cylindrical smooth surface 25b forming a minute gap 26 (see FIG. 1) is formed between the large diameter portion 25 and the inner periphery of the first friction material 18. This cylindrical smooth surface 25b is
(See FIG. 1) to perform the transfer of magnetism.

Inner peripheral surface 25c outside the front surface (left side in FIG. 4) of large diameter portion 25
Are provided in a tapered shape. This is the first friction material
When transferring magnetism between 18 and the bypass magnetic path member 21,
This is to prevent the magnetism from leaking to other members.

Further, on the front surface of the large diameter portion 25, as shown in FIG.
A groove 25d is formed. The groove 25d is used to apply a torsional force to the bypass magnetic path member 21 when the bypass magnetic path member 21 is screwed into the cylindrical portion 14 (see FIG. 1) of the support member 5 or when the bypass magnetic path member 21 is removed. Things.

 Next, the second rotating body 7 will be described.

The second rotator 7 receives rotation power from the first rotator 6, rotates, and rotates integrally with the drive shaft 2. The second rotating body 7 is
It mainly comprises an inner hub 27, a leaf spring 28, and a second friction material 29.

The inner hub 27 is mounted around the end of the drive shaft 2 and is fixed to the drive shaft 2 by a bolt 31 via a large diameter washer 30.

The second friction material 29 is connected to the inner hub 27 via a leaf spring 28. The leaf spring 28 and the second friction material 29 are fixed by rivets 32, and the leaf spring 28 and the inner hub 27 are fixed by rivets 33. By the action of the leaf spring 28, the second friction material 29 acts in a direction away from the first friction material 18. The second friction material 29 has a ring shape. Second
The material of the friction material 29 is made of a magnetic material such as iron. Second
The rear surface of the friction material 29 is a smooth second friction surface 34.
The second friction surface 34 frictionally engages with the first friction surface 22 by the magnetic force generated by the exciting coil 4. The second friction material 29 has a second magnetic blocking slot 35 formed over substantially the entire circumference.

Rivets 33 for fixing leaf spring 28 and inner hub 27
Is plate-shaped, and a plate hub 36 for balancing rotation is fixed. A stopper cushion 37 made of an elastic member such as a rubber material is fixed to the plate hub 36 by press-fitting. This stopper cushion 37 is a second friction material.
29 is forcibly displaced rearward to position the second friction material 29. With this positioning, the gap between the first friction surface 22 and the second friction surface 34 when the energization of the excitation coil 4 is stopped is about 0.5 mm.

 Next, the operation of the above embodiment will be briefly described.

During operation of the refrigeration cycle, when the exciting coil 4 is energized by the operation of a control device (not shown), the exciting coil 4 generates a magnetic force.

At this time, the first magnetic path A and the second magnetic path B are formed in the magnetic material covering the exciting coil 4 by the magnetic force generated by the exciting coil 4. The first magnetic path A is a magnetic path passing through the inner peripheral magnetic path member 17 on the outer periphery of the rolling bearing 20. The second magnetic path B is a magnetic path that bypasses the inner peripheral magnetic path member 17 and passes through the bypass magnetic path member 21 and the cylindrical portion 14 on the inner periphery of the rolling bearing 20.

In this embodiment, the thickness of the inner peripheral magnetic path member 17 is reduced,
Even if the magnetic resistance of the magnetic path A increases, the magnetic resistance is reduced by the second magnetic path B, so that the total magnetic resistance is the same as that of the related art (the inner peripheral magnetic path member is thicker). That is,
Even if the diameter of the first rotating body 6 is reduced, the engagement force between the first friction material 18 and the second friction material 29 can be made equal to the conventional one.

As a result, the magnetic force generated by the exciting coil 4 causes the second
The friction material 29 is displaced toward the first friction material 18 against the holding force of the leaf spring 28 so that the first friction surface 22 and the second friction surface 34 are in close contact with each other, and the rotational power of the engine is reduced by the refrigerant compressor 1. To the drive shaft 2.
Since the diameter of the first rotating body 6 is smaller than that of the conventional rotating body, the rotational power transmitted to the drive shaft 2 is increased by the pulley ratio.

As described above, the refrigerant compressor 1 having a small diameter and a small volume is provided.
However, the same performance as the conventional large-sized refrigerant compressor 1 can be exhibited.

When the energization of the exciting coil 4 is stopped, the magnetic force generated by the exciting coil 4 disappears. Then, the second friction material 29 is separated from the first friction material 18 by the return force of the leaf spring 28,
The rotational power transmitted to the first rotating body 6 is the second rotating body 7,
And it is not transmitted to the drive shaft 2 of the refrigerant compressor 1.

On the other hand, the gap 26 between the first rotating body 6 and the bypass magnetic path member 21
Is desirably set as small as possible for the purpose of reducing the magnetic resistance. Then, it becomes difficult for dust, water, and the like to enter the rolling bearing 20, and the initial performance of the rolling bearing 20 can be maintained for a long time.

 FIG. 5 shows a second embodiment of the present invention.

In this embodiment, an oil holding groove 38 is formed on the inner peripheral surface of the bypass magnetic path member 21.

Even if oil leaks from the refrigerant compressor 1 side to the first friction surface 22 and the second friction surface 34 via the shaft seal 15, the leaked oil accumulates in the oil holding groove 38 of the bypass magnetic path member 21. Therefore, even if oil leaks from the shaft seal 15, the engaging force of the electromagnetic clutch 3 does not decrease.

 FIG. 6 shows a third embodiment of the present invention.

In the present embodiment, the rear end of the bypass magnetic path member 21 restricts the shaft seal 15 from moving forward.

According to this embodiment, without removing the electromagnetic clutch 3 from the refrigerant compressor 1, the second rotor 7 and the bypass magnetic path member can be removed.
The shaft seal 15 can be replaced only by attaching and detaching the shaft 21.

 FIG. 7 shows a fourth embodiment of the present invention.

In this embodiment, the support member 5 is provided integrally.
That is, the stator housing and the inner housing (see the first embodiment) shown in the above embodiment are integrally provided.

 FIG. 8 shows a fifth embodiment of the present invention.

In the present embodiment, the front end of the cylindrical portion 14 is extended to form a male screw 39 on the outer periphery thereof, and the female screw 40 is formed on the inner circumference of the bypass magnetic path member 21, and the bypass magnetic path member 21 is formed around the cylindrical portion 14.
Are screwed together and fixed.

(Modification) In the present embodiment, an example is shown in which the bypass magnetic path member is fixed to the support member by screwing, but it may be fixed by another joining method.

Although an example in which the present invention is applied to a refrigerant compressor of a refrigeration cycle for a vehicle has been described, a refrigerant compressor of a household or commercial refrigeration cycle, as well as a supercharger or an automatic transmission, may be used.
The present invention can be applied to all electromagnetic clutches that transmit and cut off rotational power.

[Brief description of the drawings]

1 to 4 show a first embodiment of the present invention. FIG. 1 is a side sectional view of an electromagnetic clutch, FIG. 2 is a front view of the electromagnetic clutch, and FIG. FIG. 4 is a side sectional view of the bypass magnetic path member. FIG. 5 is a side sectional view of an electromagnetic clutch showing a second embodiment. FIG. 6 is a side sectional view of an electromagnetic clutch showing a third embodiment. FIG. 7 is a side sectional view of an electromagnetic clutch showing a fourth embodiment. FIG. 8 is a side sectional view of an electromagnetic clutch showing a fifth embodiment. FIG. 9 is a side sectional view of a conventional electromagnetic clutch. In the figure, 3 ... Electromagnetic clutch, 4 ... Exciting coil 5 ... Support member, 6 ... First rotating body 7 ... Second rotating body, 17 ... Inner magnetic path member 18 ... First friction material, 20: Rolling bearing 21: Bypass magnetic path member 26: Minute gap, 29: Second friction material

Claims (1)

(57) [Claims] (A) an annular exciting coil that generates a magnetic force when energized; and (b) a substantially cylindrical shape disposed on the inner periphery of the exciting coil, the inner periphery being supported by a bearing. A first rotating body having an inner peripheral magnetic path member made of a magnetic material and a ring-shaped first friction material made of a magnetic material; and (c) a ring-shaped member arranged opposite to the first friction material. A rotatable second rotator provided with a second friction material made of a magnetic material capable of frictionally engaging with the first friction material; and (d) supporting the bearing from an inner periphery thereof, and And a support member made of a magnetic material that supports the exciting coil on the side opposite to the second friction material, wherein the support member comprises the first friction member on the second friction material side relative to the bearing. Form a small gap between the inner peripheral surface of the rotating body Electromagnetic clutch, characterized in that the bypass magnetic flux path member made of a sex material is secured.