JPH06193653A - Electromagnetic clutch - Google Patents

Abstract

PURPOSE:To decrease any torque fluctuation by contracting either one volume of a first volume chamber and a second volume chamber while expanding the other volume according to the elastic deformation of a rubber hub. CONSTITUTION:When the relative rotation is generated between an inner hub 13 and an outer hub 12, either one volume in a first volume chamber 18a and a second volume chamber 18b is contracted, while the other volume is expanded because an elastic deformation in the rotational direction is generated on a rubber hub 14. At this time, viscous fluid sealed in a variable volume chamber 18 flows in the variable volume chamber 18 according to the contraction and expansion of the first volume chamber 18a and the second volume chamber 18b. This viscous fluid to flow in the variable volume chamber 18 passes through a communicating passage 18c when it is moved to the volume chamber side wherein the volume is expanded from that wherein the volume is contracted. At this time, flow resistance is produced according to the cross-sectional area of the communicating passage 18c and the viscosity of viscous fluid, this flow resistance acts as damping force. Thereby the torque fluctuation can be decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch that interrupts transmission of rotational power.

[0002]

2. Description of the Related Art Conventionally, in an electromagnetic clutch mounted on a refrigerant compressor of a vehicle refrigeration cycle, a rubber hub is interposed between an inner hub fixed to a rotary shaft of the refrigerant compressor and an outer hub fixing an armature. By making the rubber hub displaceable in the torque transmitting direction, it has an effect of reducing torque fluctuation on the refrigerant compressor side.

[0003]

However, since the damping effect of the rubber hub is limited, the effect of reducing the torque fluctuation cannot be said to be sufficient. Therefore, in the frequency range near the torsional resonance point of the vibration system of the electromagnetic clutch and the refrigerant compressor, the torque fluctuation increases, and when the resonance range is close to the resonance point of the vehicle, the synergistic effect increases noise, There was a problem that noise was transmitted to the passenger compartment. The present invention has been made based on the above circumstances, and an object thereof is to provide an electromagnetic clutch that reduces torque fluctuations.

[0004]

In order to achieve the above-mentioned object, the present invention provides an exciting coil which generates a magnetic force when energized, a driving member which is rotationally driven by a power source, and an exciting coil. When energized, it is attracted to the drive member
A rotary member that rotates integrally with the drive member, a driven member that rotates integrally with the driven shaft, and a rotary member that is interposed between the rotary member and the driven member and is elastically deformable between them. A rubber hub that transmits the rotational force of the rotating member to the driven member when the exciting coil is energized and returns the rotating member to the initial position when the exciting coil is de-energized; Side and the driven member side, the torque fluctuation reducing means for reducing torque fluctuation is provided, and the torque fluctuation reducing means is formed at different positions in the rotation direction between the rotating member and the driven member, and A variable volume including a first volume chamber and a second volume chamber that change in volume due to elastic deformation of the rubber hub in the rotation direction, and a communication passage that connects the first volume chamber and the second volume chamber in the rotation direction. A chamber and a viscous fluid enclosed in the variable volume chamber, the volume of the first volume chamber contracts or expands as the rubber hub elastically deforms in the rotational direction, and the volume of the second volume chamber expands. Is provided so as to expand or contract as technical means.

[0005]

In the electromagnetic clutch of the present invention having the above structure, the rotating shaft is rotated by transmitting the rotational force of the rotating member to the driven member via the rubber hub. When the torque fluctuation on the rotated shaft side is transmitted to the electromagnetic clutch at the same time as the rotation of the rotated shaft, a relative torsional vibration is generated between the rotating member and the driven member. As a result, the rubber hub interposed between the rotating member and the driven member elastically deforms in the rotation direction, and the elastic deformation of the rubber hub causes the volume of the first volume chamber to contract or expand, resulting in the second volume. The volume of the chamber expands or contracts. As a result, the viscous fluid enclosed in the variable volume chamber flows in the variable volume chamber according to the contraction and expansion of the first volume chamber and the second volume chamber. The viscous fluid flowing in the variable volume chamber passes through the communication passage when moving from the volume chamber side where the volume contracts to the volume chamber side where the volume expands. At this time, a flow resistance is generated according to the flow passage cross-sectional area of the communication passage and the viscosity of the viscous fluid, and the flow resistance acts as a damping force to reduce the torque fluctuation.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electromagnetic clutch of the present invention will be described below with reference to FIGS. 1 is a sectional view of the electromagnetic clutch, and FIG. 2 is a sectional view taken along the line AA of FIG. The electromagnetic clutch 1 of the present embodiment is mounted on a refrigerant compressor (not shown) of a vehicle refrigeration cycle and transmits the rotational power of the engine to the drive shaft 2 of the refrigerant compressor as needed. This electromagnetic clutch 1 is roughly classified into an exciting coil 3, a stator housing 4 that holds the exciting coil 3, a clutch rotor 5 that rotates by transmitting rotational power of the engine, and a clutch rotor 5 when the exciting coil 3 is energized. An armature 6 that is attracted to one end surface side (the left surface side in FIG. 1), a hub assembly that supports this armature 6 (described later),
And a torque fluctuation reducing means (described later) for reducing the torque fluctuation transmitted from the refrigerant compressor.

The exciting coil 3 is a well-known one in which a conductive wire coated with an insulating coating is wound around the resin bobbin 7 and generates a magnetic force when energized. The stator housing 4 forms a magnetic path of the exciting coil 3 together with the clutch rotor 5 and the armature 6. The clutch rotor 5 is
The refrigerant compressor has an annular U-shaped cross section (an inverted U-shape in FIG. 1) that covers the exciting coil 3 supported by the stator housing 4 from one end side, and a refrigerant compressor via a ball bearing 8 arranged on the inner periphery thereof. Is rotatably supported by the housing 9. The clutch rotor 5 has a pulley 10 fixed to the outer circumference in the radial direction and is rotated by the rotational power of the engine transmitted via a multi-stage V-belt (not shown) that is wound around the pulley 10. Also, the clutch rotor 5
Is provided with a smooth friction surface at one end surface in the axial direction (left surface in FIG. 1), and blocks the magnetism acting on the clutch rotor 5 at the time of energization of the exciting coil 3 near the inner circumference and the outer circumference in the radial direction. A long hole 5a for circumventing the magnetic flux flowing in the radial direction is formed over almost the entire circumference.

The armature 6 is in the shape of a hollow disk and has a predetermined gap in the axial direction and is arranged to face the friction surface of the clutch rotor 5. This armature 6
The other end surface facing the friction surface of the clutch rotor 5 is a smooth friction surface, and when the exciting coil 3 is energized, it is attracted to the clutch rotor 5 side, and the friction surface of the clutch rotor 5 is engaged with the friction surface of the clutch rotor 5. Rotate together. Further, as in the clutch rotor 5, the armature 6 is provided with a long hole 6a for cutting off the magnetism acting on the armature 6 when the exciting coil 3 is energized and circumventing the magnetic flux flowing in the radial direction. It is formed over. A ring shield 11 sandwiched between the clutch rotor 5 and the ball bearing 8 is provided on the inner peripheral side between the friction surface of the clutch rotor 5 and the friction surface of the armature 6. This ring shield 11
Is provided so as to extend in the axial direction from the clutch rotor 5 side to the armature 6 side, and when the clutch rotor 5 rotates, oil, lubricant, etc. scatter and adhere to the friction surface of the clutch rotor 5 and the friction surface of the armature 6. To prevent this. The stator housing 4, the clutch rotor 5, and the armature 6 are each made of a magnetic material such as iron or low carbon steel.

The hub assembly includes an outer hub 12 for fixing the armature 6, an inner hub 13 arranged coaxially with the outer hub and arranged on the inner peripheral side of the outer hub 12, and a rubber hub 1 for connecting the outer hub 12 and the inner hub 13.
4 and. The outer hub 12 has an annular shape with an L-shaped cross section (inverted L-shaped in FIG. 1), and
Is fixed to the outer peripheral portion of the rivet 15 with three rivets 15. The inner hub 13 is provided in a stepped cylindrical shape and is fixed to the drive shaft 2 of the refrigerant compressor. As shown in FIG. 2, the inner hub 13 is provided with three protrusions 16 integrally formed with the inner hub 13 on the outer peripheral side thereof.
The rubber hub 14 is interposed between the inner peripheral surface of the outer hub 12 and the outer peripheral surface of the inner hub 13 in the radial direction, and is adhesively fixed to the both, and the friction surface of the clutch rotor 5 and the armature 6 are secured.
It is set so that a gap of about 0.5 mm is maintained between the friction surface and the friction surface when the energization of the exciting coil 3 is stopped.
When the exciting coil 3 is energized, the rubber hub 14
Since the armature 6 is attracted to the clutch rotor 5 side, the outer hub 12 that moves integrally with the armature 6
And an inner hub 13 fixed to the drive shaft 2 of the refrigerant compressor.
When elastically deforms in the axial direction between and, and when the energization to the exciting coil 3 is stopped, the elastic force causes the armature 6 to return to the initial position (the position shown in FIG. 1). As shown in FIG. 2, the rubber hub 14 has an inner hub 1
The depressions 14a are formed at three locations in the circumferential direction so that a space is formed around the protrusion 16 formed integrally with the protrusion 3.

The torque fluctuation reducing means is a variable volume chamber 18 (see FIG. 2) formed by sealing the recess 14a formed in the rubber hub 14 with a sealing member 17 (see FIG. 1).
And a viscous fluid (for example, silicone oil, grease-like fluid, etc.) enclosed in the variable volume chamber 18. The sealing member 17 is fixed by tightening the screw 20 in the screw holes 19 provided in the protrusions 16, respectively. The variable volume chamber 18 is, as shown in FIG.
4 are formed between the first volume chamber 18a and the second volume chamber 18b formed on both sides of the protrusion 16 in the circumferential direction of 4, and the outer hub 12 on the tip side of the protrusion 16, and the first volume chamber 18 is formed.
communication passage 18c that connects a and the second volume chamber 18b in the circumferential direction
Consists of First volume chamber 18a and second volume chamber 18b
Is formed by sealing the recess 14a of the rubber hub 14, so that its volume changes as the rubber hub 14 elastically deforms. In particular, the inner hub 13 and the outer hub 12
When a relative rotation occurs between and, the rubber hub 14 is elastically deformed in the rotation direction, so that the volumes on both sides of the protrusion 16 change. That is, either one of the first volume chamber 18a and the second volume chamber 18b contracts, and the other volume expands. At this time, the viscous fluid sealed in the variable volume chamber 18 is not included in the first volume chamber 18a and the second volume chamber 18a.
It flows in the variable volume chamber 18 according to the contraction and expansion of b.

Next, the operation of this embodiment will be described. The armature 6 is attracted to the clutch rotor 5 side against the elastic force of the rubber hub 14 by the magnetic force generated by the energization of the exciting coil 3. As a result, the friction surface of the clutch rotor 5 and the friction surface of the armature 6 are in close contact with each other and frictionally engage with each other, so that the rotational power of the engine transmitted through the pulley 10 is transmitted through the hub assembly to the drive shaft of the refrigerant compressor. Two
Be transmitted to. Here, when the load torque applied to the drive shaft 2 of the refrigerant compressor fluctuates due to the compression action of the refrigerant, the torque fluctuation is transmitted from the drive shaft 2 to the electromagnetic clutch 1. As a result, a relative torsional vibration is generated between the inner hub 13 and the outer hub 12, and the rubber hub 1 interposed between the inner hub 13 and the outer hub 12 is generated.
4 elastically deforms in the direction of rotation. With the elastic deformation of the rubber hub 14, for example, when the first volume chamber 18a contracts and the second volume chamber 18b expands, the variable volume chamber 18
A part of the viscous fluid sealed in is moved from the first volume chamber 18a to the second volume chamber 18b through the communication passage 18c. Needless to say, when the first volume chamber 18a expands and the second volume chamber 18b contracts, the behavior opposite to the above is exhibited. When the viscous fluid flows through the communication passage 18c, flow resistance occurs depending on the flow passage cross-sectional area of the communication passage 18c and the viscosity of the viscous fluid. The flow resistance acts as a damping force to reduce the torque fluctuation transmitted from the refrigerant compressor. The effect of reducing this torque fluctuation is shown in FIG.
The graph of FIG. 3 shows the relationship between the one-sided amplitude torque and the frequency of the torque fluctuation, where ΔT represents the excited one-sided amplitude torque of the refrigerant compressor, and the frequency of the torque fluctuation is the rotational speed of the refrigerant compressor and 1 :. There is a relationship of 1. The electromagnetic clutch 1 of this embodiment is shown by a solid line graph, and the conventional electromagnetic clutch is shown by a broken line graph.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 is a cross-sectional view of the electromagnetic clutch 1, and FIG. 5 is a B view of FIG. Electromagnetic clutch 1 of this embodiment
Is different from the first embodiment in the structure of the hub assembly and the torque fluctuation reducing means, which will be described below. In addition,
Parts having the same name are assigned the same numbers as in the first embodiment. As shown in FIG. 6 (disassembled perspective view of the hub assembly), the hub assembly includes an inner hub 13, an outer hub 12,
It comprises a plate 21 and a rubber hub 14. The inner hub 13 has an inner peripheral wall 13b forming an annular space 13a.
And the outer peripheral wall 13c, and the protrusion 13d in the space 13a.
Are provided in three places. The outer hub 12 includes a ring portion 12a having a hollow ring shape and a leg portion 12b extending from an outer peripheral edge of the ring portion 12a. A rivet 15 is provided on the outer peripheral portion of the armature 6 via the leg portion 12b. Fixed. The plate 21 is adhesively fixed to the annular portion 12a of the outer hub 12, and has an annular adhesive portion 21a along the annular portion 12a and three protruding portions 21b. The protrusion 21 b is provided in the space 13 of the inner hub 13.
It has a size that can be stored in a.
It is provided continuously with a. The rubber hub 14 is sandwiched between the inner hub 13 and the plate 21 in such a manner that the protrusion 13d of the inner hub 13 and the protrusion 21b of the plate 21 mesh with each other, and is housed in the space 13a of the inner hub 13. As shown in FIG. 6, the rubber hub 14 is provided with six thick portions 14b which are sandwiched between the protrusion 13d of the inner hub 13 and the protrusion 21b of the plate 21 in the circumferential direction. The thick portions 14b are alternately connected by arcuate flat plate portions 14c on both sides in the axial direction so that the protrusions 13d of the inner hub 13 and the protrusions 21b of the plate 21 are inclined. In the rubber hub 14, in the state of the hub assembly, between the protrusions 13d and 21b of the inner hub 13 and the plate 21 and the flat plate portion 14c connecting the pair of thick portions 14b sandwiching the protrusions 13d and 21b, the exciting coil is provided. 3 is provided so as to have a constant clearance even when the armature 3 is energized (the armature 6 is attracted to the clutch rotor 5 side) (see FIG. 7 and C- in FIG. 5).
(C sectional view)).

The torque fluctuation reducing means includes a rubber hub 14, an inner hub 13, and a plate 21 in a hub assembly state.
And a variable volume chamber 18 (see FIG. 7) formed between the variable volume chamber 18 and the variable volume chamber 18, and a viscous fluid enclosed in the variable volume chamber 18. The variable volume chamber 18 includes a first volume chamber 18a and a second volume chamber 18b formed on both sides of the protrusion 13d of the inner hub 13 and the protrusion 21b of the plate 21, respectively, and the protrusions 13d and 21b and the flat plate portion 14c. And a communication passage 18c formed between the first volume chamber 18a and the second volume chamber 18b. First volume chamber 18a and second
The volume of the volume chamber 18b changes as the rubber hub 14 elastically deforms. Therefore, when relative rotation occurs between the inner hub 13 and the outer hub 12, the rubber hub 14
Since elastic deformation occurs in the rotation direction, each protrusion 13d,
The volume on both sides of 21b changes. That is, the first volume chamber 1
Either the volume of 8a or the second volume chamber 18b contracts, and the volume of the other expands. At this time, the viscous fluid enclosed in the variable volume chamber 18 moves from the contracting volume chamber side to the expanding volume chamber side through the communication passage 18c.
As a result, as in the first embodiment, the flow resistance generated when the viscous fluid passes through the communication passage 18c acts as a damping force, so that the torque fluctuation transmitted from the refrigerant compressor is reduced.

[Modification] In the first embodiment, the protrusion 1
An example in which 6 is formed integrally with the inner hub 13 has been shown.
As shown in FIG. 8, the protrusion 16 may be formed integrally with the outer hub 12. In addition, in the second embodiment, each thick wall portion 14b is formed by the inner hub 13 and each projection portion 1 of the plate 21.
Although the case where there is an inclination (see FIG. 7) sandwiching 3d and 21b is shown, as shown in FIG. 9, it may have an opposite inclination.

[0015]

In the electromagnetic clutch of the present invention, when a relative torsional vibration is generated between the rotating member and the driven member, the viscous fluid flowing in the variable volume chamber along with the elastic deformation of the rubber hub communicates with the communicating passage. Flow resistance when passing through acts as a damping force. As a result, the torque fluctuation transmitted from the rotated shaft side can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an electromagnetic clutch according to a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a graph showing a torque fluctuation reducing effect (first embodiment).

FIG. 4 is a sectional view of an electromagnetic clutch according to a second embodiment.

5 is a view from B of FIG. 4. FIG.

FIG. 6 is an exploded perspective view of a hub assembly according to a second embodiment.

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

FIG. 8 is a sectional view of a hub assembly including a variable volume chamber according to a modified example of the first embodiment.

FIG. 9 is a sectional view of a hub assembly including a variable volume chamber according to a modification of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electromagnetic clutch 2 Drive shaft (rotated shaft) 3 Excitation coil 5 Clutch rotor (driving member) 6 Armature (rotating member) 12 Outer hub (rotating member) 13 Inner hub (driven member) 14 Rubber hub 18 Variable volume chamber 18a First volume chamber 18b Second volume chamber 18c Communication passage

Claims (1)

[Claims] 1. An exciting coil that generates a magnetic force by being energized, a driving member that is driven to rotate by a power source, and is attracted to the driving member when the exciting coil is energized to be integrated with the driving member. A rotating member that rotates, a driven member that rotates integrally with the rotated shaft, and an elastically deformable member that is interposed between the rotating member and the driven member and that is elastically deformable between them. A rubber hub that transmits the rotational force of the rotating member to the driven member when energized and returns the rotating member to the initial position when the energization of the exciting coil is stopped; the rotating member side and the driven member side. Torque fluctuation reducing means for reducing torque fluctuations between the rubber hub and the rubber hub, the torque fluctuation reducing means being formed at different positions in the rotational direction between the rotating member and the driven member. A variable volume chamber including a first volume chamber and a second volume chamber that change in volume due to elastic deformation that occurs in the rotation direction of the first volume chamber, and a communication passage that connects the first volume chamber and the second volume chamber in the rotation direction. And a viscous fluid enclosed in the variable volume chamber, the volume of the first volume chamber contracts or expands as the rubber hub elastically deforms in the rotation direction, and the volume of the second volume chamber increases. An electromagnetic clutch characterized by being provided so as to expand or contract.