JPH05312224A - Electromagnetic connecting device - Google Patents

Abstract

PURPOSE:To provide a device which can improve close contact between a friction face of a rotor and a friction face of an armature, restrain generation of noise such as rattling or attracting noise and reduce the size of the device. CONSTITUTION:A plurality of ark-state slits 38 are provided with almost an equal interval on almost the same circumference of a plate-state armature 34. Straight slits 39 are provided extending from one ends of these ark-state slits 38 in the radial direction of the armature 34. By providing both the slits 38 and 39, arc pieces 40 are formed surrounded by both the slits 38 and 39.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic coupling device such as an electromagnetic clutch for connecting / disconnecting rotation transmission of a rotating body by exciting or non-exciting an electromagnetic coil and an electromagnetic brake for braking rotation of the rotating body.

[0002]

2. Description of the Related Art For example, a crank pulley of a vehicle engine and a pulley provided in an auxiliary machine (hereinafter referred to as an auxiliary machine) such as a compressor for an air conditioner or a pump for a power steering (hereinafter referred to as an auxiliary machine) are belt devices equipped with a transmission. In the case of an auxiliary machine that is drive-connected with the auxiliary machine that does not require the auxiliary machine to rotate at a speed higher than the appropriate rotational speed, an electromagnetic clutch is provided between the pulleys of the transmission and the electromagnetic clutch is turned on. The OFF speed is controlled so that the speed of the auxiliary machine does not exceed the appropriate speed, and the engine power is saved, the noise of the auxiliary machine is reduced, and the size and weight are reduced.

A transmission equipped with this type of electromagnetic clutch has conventionally been constructed as follows. That is, on the cylindrical housing supported by the rotating shaft on the machine body side, the rotor connected to the engine and the belt and the armature hub connected to the compressor as the auxiliary machine and the belt are freely rotatable via bearings. And, the annular field core supported by the flange of the housing via a mounting plate is provided in the annular groove provided in the rotor of the rotors, the movement of which is restricted in the axial direction. It is engaged. An electromagnetic coil is internally provided in the annular groove of the field core, and the armature hub is bolted to a disc-shaped coupling fixed to the protruding portion of the rotary shaft from the housing, so that An armature supported on the plane of the armature hub via a leaf spring is interposed between the planes facing the armature hub.

With such a configuration, when the electromagnetic coil is excited while the engine is rotating and the rotor connected to the engine is rotating, a magnetic flux that bypasses the rotor and the armature is formed. By being
Since the armature is attracted to the frictional surface of the rotor against the spring force of the leaf spring and the armature and rotor are integrated, the armature hub integrated with the armature rotates in the rotation direction, and the compression of the armature hub and the belt connection The machine rotates. If the electromagnetic coil is demagnetized from this state,
The restoring force of the leaf spring causes the armature to move away from the friction surface of the rotor to stop the armature hub, and the compressor connected to the armature hub to stop.

[0005]

In the electromagnetic clutch operating in this way, there has been a problem in the structure of the rotor and the armature. FIG. 10 is a longitudinal sectional view of a conventional rotor, and FIG. 11 is a front view of the same. A rotor 1 has an inner pole member 2 formed in an annular shape having an L-shaped cross section, and an annular outer pole welded to an outer peripheral portion thereof. The outer pole member 3 is integrally formed with the member 3, and the V-groove 5 for abutting the belt 4 drivingly connecting the engine and the rotor 1 is provided on the peripheral surface of the outer pole member 3, as described above. The friction surface 6 for adsorbing the armature (not shown) is formed with three slits 7 concentrically formed and divided in the circumferential direction by press punching.

A belt 4 is attached to the rotor 1 constructed as described above.
Rotor friction surface 6 as a result of a test in which
When the tension BT of the belt 4 is set to 100 kg, the distortion of No. 2 has the results shown in FIGS. That is,
12 is a diagram showing the position of the rotor 1 in the diametrical direction on the horizontal axis and the magnitude of strain t on the vertical axis, and FIG. 13 is a longitudinal sectional view of the rotor showing the state of strain. Friction surface 6
A section a ₁ -a ₂ and B section b ₁ -on a straight line passing through the center of
The distributions of the distortions at b ₂ and are curved as shown by symbols L _{1 and} L ₂ in FIG. Here, L ₁ is the belt 4 in FIG.
3 shows a curve when applied only to the V groove on the side of the friction surface 6 shown by reference numeral 4A, and L ₂ is the belt 4,
FIG. 13 shows a curve when it is applied only to the V groove on the side opposite to the friction surface 6 shown by reference numeral 5B. A curved line shown in FIG. 12 and a chain line 6 exaggeratingly showing the strained state of the friction surface 6 in FIG.
As is clear from A, the frictional surface 6 of the rotor 1 has different wavy distortions on the inner diameter side and the outer diameter side.

FIG. 14 is a longitudinal sectional view of a conventional armature, and FIG. 15 is a front view of the same. The armature 8 is formed into a disc shape by punching a steel plate, and its friction surface 11 is formed. In this case, two slits 9 which are concentrically formed and divided in the circumferential direction are formed by press punching. Reference numeral 10 designates a rivet hole for rivets which is provided at three equally divided positions in the circumferential direction as shown by reference numeral R for fixing the leaf spring. Since such an armature 8 is punched by a press, a strain that gradually increases from the inner peripheral side to the outer peripheral side is generated during this processing.

As described above, in the conventional electromagnetic clutch, the rotor 1 and the armature 8 constitute a magnetic circuit depending on the above-mentioned use conditions and manufacturing conditions, and the hot-rolled mild steel plate and the mechanical structure. The friction surface 6 of the rotor 1 and the friction surface 11 of the armature 8 are distorted due to being formed of a material having relatively low rigidity such as carbon steel for use.

Accordingly, when the friction surface 11 of the armature 8 is magnetically attracted to the friction surface 6 of the rotor 1 and the torque rises, the friction surface 11 of the armature 8 partially sticks to the friction surface 6 of the rotor 1. When a so-called stick-slip phenomenon of slipping occurs, there is a problem that the rotor 1 and the armature 8 are easily vibrated, and this phenomenon is prominent when abrasion powder adheres to the friction surfaces 6 and 11. .. Further, in the case of a disc-shaped disc or the like, if the weight in the circumferential direction is made uniform or the members are attached at equal intervals, a resonance waveform due to equal division in the circumferential direction is likely to occur, and there is a problem that a squeal is generated. ..

Further, FIGS. 16 to 19 show the test results of the same structure other than the electromagnetic coupling device according to the present invention and the armature, without the radial slit of the armature.
6 is a diagram showing the frequency analysis result, FIG. 17 is a diagram showing the radio wave waveform of the microphone, FIG. 18 is a diagram showing the operating characteristics of the electromagnetic clutch, and FIG. 19 is a diagram showing the suction sound evaluation result. According to the frequency analysis result by the FFT analyzer of FIG. 16, the sound pressure level DB is 113 dB when the number of times of attachment and detachment is 2000. Further, looking at the operation characteristics of FIG. 18, the suction time of the armature is 37.90 ms. FIG. 19 shows the adsorption sound when the electromagnetic clutch is attached to the car air-conditioning compressor, that is, the sound of the armature hitting the rotor for each attachment / detachment. It has been shown.

Further, the problem of the generation of abnormal noise due to such vibration is, as disclosed in US Pat. No. 3,368,657, US Pat. No. 3,307,669 and US Pat. No. 3,727,736, the problem of armature. Although measures such as dividing the vibration part to attenuate audible vibration or setting the natural frequency of vibration to outside the audible range have been proposed, there is a problem that a satisfactory effect cannot be expected.

[0012] Further, Japanese Utility Model Publication No. 2-1541 discloses that a rubber as a damping material is brought into contact with an armature or a rotor to reduce the occurrence of abnormal noise due to vibration. However, there is a problem in that the damping effect of rubber is reduced and the vibration damping action is reduced.

The present invention has been made in view of the above points. By changing the vibration mode of the resonance frequency and improving the adhesion of the friction surface, abnormal noise such as squeaking noise or suction noise is generated. It is an object of the present invention to provide an electromagnetic coupling device that enables suppression and downsizing of the device.

[0014]

In order to achieve such an object, according to the present invention, in an electromagnetic coupling device in which a friction surface of an armature is attracted to a friction surface of a rotor to transmit power, the armature is almostゞ Provide a plurality of arc-shaped slits arranged on the same circumference to bypass the magnetic flux, and linear slits that extend in the radial direction of the armature from one end of the arc-shaped slit and open to the inner or outer circumference of the armature. An arc piece surrounded by the arc slit and the linear slit was formed.

[0015]

When the electromagnetic coil is excited, a magnetic flux that bypasses the slit of the rotor and the slit of the armature is formed, and the friction surface of the armature is magnetically attracted to the friction surface of the rotor. Power is transmitted between the rotating body on the armature side, but when the armature is magnetically attracted to the rotor and the torque rises, the arc surface surrounded by the slit is provided on the armature, and the friction surface The rotors and armatures are hard to vibrate because they are in close contact with each other, and a resonance waveform due to equal division in the circumferential direction is unlikely to occur and no squeaking noise is generated.

[0016]

1 to 7 show an example in which the electromagnetic coupling device according to the present invention is applied to an electromagnetic clutch of a compressor for a car air conditioner, FIG. 1 is a front view of the electromagnetic clutch, and FIG. 2 is FIG.
II-II sectional view of FIG. 3, FIG. 3 is a front view of the armature as seen from the friction surface side of FIG. 2, FIG. 4 is a front view of the rotor as seen from the friction surface side of FIG. 2, and FIG. 5 is a frequency corresponding to FIG. Is a diagram showing the analysis result of FIG. 6, FIG. 6 is a diagram showing a radio wave waveform of the microphone corresponding to FIG. 17, and FIG. 7 is a diagram showing operation characteristics of the electromagnetic clutch corresponding to FIG.

1 to 3, a field core 22 having an annular groove 22a is fixed to an end surface of a housing 21 of the compressor by a plurality of bolts 23, and a power source is connected to the annular groove 22a. A ring-shaped electromagnetic coil 24 is provided inside, and a cylindrical portion 21a of the housing 21 is provided at the center of the field core 22 so as to project from the housing body. The reference numeral 25 indicates a rotor rotatably supported by the cylindrical portion 21 a of the housing 21 via a bearing 26, and the annular groove 2 of the rotor 25.
An annular portion of the field core 22 in which an electromagnetic coil 24 is installed is engaged with 5a, and a rotor 25
A V-belt groove 25b is formed on the outer periphery of the V-belt groove 25b by which the V-belt 27 stretched and abutted on the V-belt groove on the engine side is abutted.

On the other hand, in the inner hole of the cylindrical portion 21 of the housing 21, the rotary shaft 2 of the compressor formed concentrically therewith.
8 is engaged, and at the engaging end of the rotary shaft 28,
An armature hub 29, which is formed in a cylindrical shape with a collar, is spline-fitted, and is fixed by a bolt 31 together with a regular triangular plate-shaped stopper plate 30 that is studded to the armature hub 29 at a distance from the rotor 25. Has been done. Reference numeral 32 is a thin bottomed cylindrical shape and is three damper covers fixed to the triangular vertex of the stopper plate 30. A compressible damper rubber 33 is loaded in each of the damper covers 32. There is.

34 is a disk-shaped damper rubber 33
An armature supported by a pin 35 integrated with the rotor 25 and disposed between the rotor 25 and the damper cover 32. The armature includes a friction surface 34a facing the friction surface 25c of the rotor 25. At the time of excitation, the damper rubber 33
The frictional surfaces 25c and 34a are arranged to face each other with an air gap G in FIG. Further, when the electromagnetic coil 24 is excited, the damper rubber 33
The friction surface 34a is configured to be adsorbed to the friction surface 25c against the elastic force of.

As shown in FIG. 4, the flat plate portion serving as the friction surface of the rotor 25 is provided with a plurality of concentric rods having different diameters and arranged at equal intervals. The magnetic flux detouring arcuate slits 36 and 37 are punched through the front and back surfaces of the flat plate portion of the rotor 25 by press punching. Further, the armature 34 has a plurality of magnetic flux detour arcuate slits 38 formed in an arcuate shape and arranged at substantially equal intervals on the same circumference, punched through the front and back sides,
From one end of each arcuate slit 38, the armature 34
A straight slit 39 extending in the radial direction of the armature 34 and opening to the inner circumference of the armature 34 is punched through the front and back by press punching. By providing both slits 38 and 39 in this manner, the armature 34 is formed with an arc piece 40 surrounded by both slits 38 and 39.
Further, between adjacent slits 38, split slits 41 extending in the radial direction of the armature 34 and opening to the inner circumference and outer circumference of the armature 34 are punched out. 42 is a pin hole for fixing the pin 35 by caulking.

The operation of the electromagnetic clutch constructed as above will be described. When the engine rotates while the electromagnetic coil 24 is in the demagnetized state, the rotor 25 belt-connected to the engine rotates, but at this time, the friction surface 34 a of the armature 34 is changed by the restoring force of the damper rubber 33 to the friction surface 25 c of the rotor 25. Since a predetermined air gap G is formed between the friction surfaces 34a and 25c away from the armature 34 and the stopper plate 30 integral with the armature 34, the rotating shaft 28 fixed via the armature hub 29 does not rotate, and Rotation is not transmitted to the compressor.

From this state, when the electromagnetic coil 24 is energized and excited, the armature 34 moves to the V-belt 2
Rotor 25 to which the rotation of the engine is transmitted via
In addition, since the magnetic attraction is exerted against the elastic force of the damper rubber 33, the rotation of the engine is transmitted to the rotary shaft 28 of the compressor equipped with the armature assembly including the armature 34, the stopper plate 30 and the armature hub 29. It

By exciting the electromagnetic coil 24 as described above, the friction surface 34a of the armature 34 is rotated by the rotor 25.
When the torque rises after being magnetically attracted to the friction surface 25c of the armature, the slits 38, 39 are formed in the armature 34.
By providing the arc piece 40 surrounded by these slits 38 and 39, the friction surfaces 25c and 34a are in close contact with each other, the rotor 25 and the armature 34 are less likely to be vibrated, and the circumferential direction is increased. Resonance waveform due to equal division is less likely to occur and no squeaking noise occurs.

FIG. 5 is a diagram showing the frequency analysis result of this apparatus corresponding to the analysis result of the conventional apparatus shown in FIG. 16. The frequency analysis result by the FFT analyzer is the 2000th number of attachment / detachment times. Conventionally 113 dB
The sound pressure level was 8 dB in this device, and the frequency characteristic has no peak.

Further, FIG. 6 is a diagram showing the appearance of the radio wave waveform of the microphone in the present device corresponding to the appearance of the conventional device shown in FIG. It will be small and will not give a driver discomfort.

Further, FIG. 7 is a diagram showing the operating characteristics of this apparatus in correspondence with the operating characteristics of the conventional apparatus shown in FIG. 18. Looking at the operating characteristics of this apparatus, the armature suction time is 37. Although it will be somewhat longer from 90 ms to 39.90 ms, since the rising of the waveform within the actual torque rising time does not rise slightly wavy like in the conventional case, the connection is performed smoothly and the rigidity of the armature is reduced. Impact is small and durability does not decrease.

FIG. 19 is a diagram showing the number of times of attachment and detachment on the horizontal line and the sound pressure level dB on the vertical axis. Curve A shows the curve of the conventional device, and curve B shows the curve of the device of the present application. ing. As is apparent from the figure, the difference in the suction sound in the device of the present application is about 15 dB except the initial stage of attachment / detachment, and no noise that causes a driver of the vehicle to feel uncomfortable. Further, in FIG. 3, the arc piece 42 surrounded by the slits 38 and 39 is formed, and the friction surface 3 of the armature 34 is formed.
Although the adhesion between 4a and the friction surface 25c of the rotor 25 is improved to reduce the diameters of the friction surfaces 34c and 25c, the transmission torque does not decrease. Furthermore, from the processing side,
All you have to do is change the type of press that punches the slit.
The price does not increase significantly.

FIGS. 8 and 9 are front views of an armature as another embodiment of the present invention.
In the embodiment shown in, the armature 51 has a plurality of magnetic flux bypass slits 52 formed in an arc shape and arranged at substantially equal intervals on the same circumference, punched through the front and back, From one end of each slit 52, linear slits 53 that extend to both sides in the radial direction of the armature 51 and open to the inner circumference of the armature 51 are punched through the front and back sides by press punching. By doing so, the armature 51 is formed with three arc pieces 54 surrounded by both slits 52 and 53. Further, the armature 5 is provided at the end of each slit 52 on the side opposite to the slit 53.
A slit 55 that extends to both sides in the radial direction of 1 and does not open to the inner circumference of the armature 51 is punched out by press. The function and effect of this armature 51 are the same as those in the above-mentioned embodiment.

Next, in the embodiment shown in FIG. 9, the armature 61 has a plurality of magnetic flux diverting slits 62 formed in an arc shape and arranged at equal intervals on the same circumference. The slits 63 are punched out, and from one end of each slit 62, slits 63 that extend to both sides in the radial direction of the armature 61 and open to the inner circumference of the armature 61 are punched through the front and back sides by press punching. By doing this, the armature 61 has both slits 62, 6
Three arc pieces 64 surrounded by 3 are formed. A slit 65 extending in the radial direction of the armature 61 and opening to the outer periphery of the armature 61 is punched between adjacent slits 62. The function and effect of this armature 61 are the same as those in the above-mentioned embodiment.

In each of the above-mentioned embodiments, the electromagnetic coupling device according to the present invention is applied to the electromagnetic clutch of the car air conditioner compressor, but the devices to which the electromagnetic coupling device is applied are not limited to the electromagnetic clutch. Can be applied and the same effect can be obtained. Further, a linear slit extending from one end of the arcuate slit in the radial direction of the armature and opening to the outer periphery of the armature may be provided, and the arcuate piece may be formed outside.

[0031]

As is apparent from the above description, according to the present invention, in the electromagnetic coupling device in which the friction surface of the armature is attracted to the friction surface of the rotor to transmit power, the armature is substantially the same circle. A plurality of arc-shaped slits arranged on the circumference to bypass the magnetic flux and a linear slit extending from one end of the arc-shaped slit in the radial direction of the armature and opening to the inner circumference or the outer circumference of the armature are provided,
By forming an arc piece surrounded by both of these slits, the adhesion between the friction surfaces of the rotor and armature becomes good, vibration of the rotor and armature during suction is suppressed, and Since the resonance waveform due to the equal division is unlikely to occur, the suction noise and the squeal noise are reduced, and the environment is improved. Further, even if the diameters of the rotor and the armature are reduced, a large torque transmission force can be secured, so that the device can be downsized.

[Brief description of drawings]

FIG. 1 is a front view of an electromagnetic clutch.

2 is a sectional view taken along line II-II of FIG.

3 is a front view of the armature as seen from the friction surface side of FIG. 2. FIG.

FIG. 4 is a front view of the rotor seen from the friction surface side of FIG.

5 is a diagram showing a result of frequency analysis corresponding to FIG.

FIG. 6 is a diagram showing a radio wave waveform of a microphone corresponding to FIG.

[Figure 7]
． FIG. 19 is a diagram showing the operating characteristics of the electromagnetic clutch corresponding to FIG. 18.

FIG. 8 is a front view of an armature as another embodiment of the present invention.

FIG. 9 is a front view of an armature as another embodiment of the present invention.

FIG. 10 is a vertical sectional view of a conventional rotor.

FIG. 11 is a front view of a conventional rotor.

FIG. 12 is a conventional relational diagram between the radial position of the rotor and the magnitude of strain.

FIG. 13 is a vertical sectional view of a rotor showing a conventional strain state.

FIG. 14 is a vertical cross-sectional view of a conventional armature.

FIG. 15 is a front view of a conventional armature.

FIG. 16 is a diagram showing a conventional frequency analysis result.

FIG. 17 is a diagram showing a radio wave waveform of a conventional microphone.

FIG. 18 is a diagram showing operating characteristics of a conventional electromagnetic clutch.

FIG. 19 is a diagram showing a suction sound evaluation result showing a comparison between the conventional device and the device of the present invention.

[Explanation of symbols]

 24 electromagnetic coil 25 rotor 25c friction surface 34 armature 34a friction surface 38 arcuate slit 39 linear slit 40 arcuate piece 41 split slit 51 armature 52 arcuate slit 53 straight slit 54 arcuate piece 55 split slit 61 armature 62 arcuate slit 63 Linear slit 64 arc piece 65 split slit

Claims (1)

[Claims] 1. An electromagnetic coupling device for exciting a magnetic coil to adsorb the friction surface of an armature to the friction surface of a rotor in which the electromagnetic coil is installed to transmit power, wherein the armature has substantially the same circumference. A plurality of arcuate slits arranged on the upper side to bypass the magnetic flux, and linear slits extending from one end of the arcuate slits in the radial direction of the armature and opening to the inner circumference or the outer circumference of the armature are provided. An electromagnetic coupling device characterized in that an arc piece surrounded by and a linear slit is formed.