JP2008095704A - Electromagnetic coupling device - Google Patents

Abstract

An electromagnetic coupling device that is inexpensive and can reliably suppress the generation of vibration and sound.
A damping member 43 is interposed in a gap 4 between the armature 2 and a worm wheel 3 that supports the armature 2. The damping member 43 is formed in a ring shape from a viscoelastic material having a damping function and a vibration damping function, and is fixed to the armature 2 with an adhesive or a double-sided adhesive tape. Further, the damping member 43 has a plate thickness larger than the gap 4 in a natural state, and is interposed between the armature 2 and the worm wheel 3 in a compressed state, whereby the armature 2 is attached to the rotor 6. Pressed.
[Selection] Figure 1

Description

  The present invention relates to an electromagnetic coupling device such as an electromagnetic clutch or an electromagnetic brake, and in particular, a gapless type electromagnetic coupling device in which the friction surfaces of the rotating members on the driving side and the driven side are in contact with each other even after the energization to the exciting coil is cut off. It is about improvement.

  Among the electromagnetic coupling devices, an electromagnetic clutch includes an armature, an armature hub (armature support member) that supports the armature so as to be movable in the axial direction, and a rotor in which the friction surface faces the friction surface of the armature through a predetermined air gap. And an elastic member made of a leaf spring or a damper rubber for supporting the armature on the armature hub, and an exciting coil, etc., and the armature has a magnetic attractive force of magnetic flux generated by energization excitation to the exciting coil. The armature and the rotor are configured to rotate together when magnetically attracted to the friction surface of the rotor against the elastic restoring force. Further, since the magnetic attractive force disappears when the energization of the exciting coil is cut off, the armature is configured to be separated from the friction surface of the rotor by the elastic restoring force of the elastic member.

  Among the electromagnetic clutches that operate in this way, in order to increase the responsiveness of the operation by increasing the suction time of the armature, or to provide a lightweight, small and inexpensive electromagnetic clutch by reducing the number of parts and assembly steps A so-called gapless type electromagnetic clutch is also put to practical use in which the armature return elastic member is removed and the friction surface of the armature and the friction surface of the rotor maintain the contact state even in the non-excitation state where the energization to the excitation coil is cut off. (For example, see Patent Documents 1, 2, and 4).

  The electromagnetic clutch described in Patent Document 1 is used as a power transmission device of a vehicle door opening / closing drive device. An output shaft to which rotation of a motor is transmitted, and a rotor fixed to the output shaft. (Driven-side rotating member), and an output drum as an output member fixed to the output shaft, and a clutch as a friction engagement mechanism provided with a reduction gear structure provided between the output drum and the motor A brake mechanism is provided. In addition to the reduction gear structure, the clutch brake mechanism includes an armature (drive side rotating member), an excitation coil, and the like. The reduction gear structure is composed of a worm and a worm wheel. The worm is fixed to the drive shaft of the motor, and the worm wheel supports the armature so as to be movable in the axial direction so as to contact the rotor. The clutch is configured.

  FIG. 2 shows a conventional example of such a gapless type electromagnetic clutch (see, for example, Patent Document 4). In this electromagnetic clutch 1, a stainless steel wave washer 5 is interposed in a gap 4 between the armature 2 and the worm wheel 3, thereby pressing the armature 2 to contact the rotor 6. The wave washer 5 has an annular portion 5A in which corrugated convex portions and concave portions are alternately formed in the circumferential direction, and a plurality of protruding portions 5B protruding from the inner peripheral surface of the annular portion 5A toward the center. Then, the annular portion 5A is compressed in the axial direction by being interposed in the gap 4, and the inner edge of the protruding portion 5B is brought into contact with the outer peripheral surface of the annular protrusion 3a of the worm wheel 3, whereby the wave washer 5 Is aligned with the axis of the worm wheel 3 to prevent the wave washer 5 from moving in the radial direction. Reference numeral 7 denotes an exciting coil, 8 denotes an output shaft, 9 denotes a motor driving shaft, 10 denotes a worm, and 12 denotes a housing.

  In such a conventional gapless type electromagnetic clutch 1, in the non-excited state where the energization to the exciting coil 7 is cut off, the friction surface 2 a of the armature 2 is caused by a slight pressing force (elastic return force) of the wave washer 5. Is pressed against the friction surface 6a. In such a contact state (connected state), when a driven member (not shown) that is manually connected to the output shaft 8 instead of the driving force of the motor, for example, the electromagnetic clutch 1 is used for a vehicle door opening / closing drive device, When the sliding door constitutes a driven member, and the sliding door is opened and closed, the rotor 6 rotates integrally with the output shaft 8 and relative rotation occurs between the rotor 6 and the armature 2. That is, the rotor 6 performs slip rotation with respect to the armature 2. In addition, since the friction surface 6a of the rotor 6 slides relative to the friction surface 2a of the armature 2 by this relative rotation, a stick-slip phenomenon that causes noise generation (microscopically between the friction surfaces in the clutch and brake). A sliding friction phenomenon when stopping or moving) occurs.

  Further, the armature 2 vibrates against the pressing force of the wave washer 5 due to the stick-slip phenomenon. When the vibration due to the stick-slip phenomenon matches the natural frequency of the armature 2, there is a possibility that a loud sound is generated.

JP 2002-327576 A Japanese Utility Model Publication 5-35033 Japanese Patent Laid-Open No. 11-190369 JP 2004-324171 A

  As described above, in the conventional gapless type electromagnetic clutch 1, the friction surface 2a of the armature 2 and the friction surface 6a of the rotor 6 are in contact with each other even when the excitation coil 7 is not excited. When the armature 2 is operated, there is a problem that the armature 2 vibrates against the pressing force of the wave washer 5 due to the stick-slip phenomenon, and a sound is generated.

  Accordingly, the present inventors have conducted various tests to solve such problems, and as a result, have found that there is a difference in sound generation depending on the flatness of the friction surface 2a of the armature 2 and the friction surface 6a of the rotor 6. It was. That is, it has been found that the stick-slip phenomenon easily occurs and the sound is generated as the flatness of the friction surfaces 2a and 6a of the armature 2 and the rotor 6 is reduced.

  For this reason, the experiment was performed with intentionally increasing the flatness of the friction surface 2a of the armature 2 within a range that does not hinder the frictional engagement between the armature 2 and the rotor 6. As a means for increasing the flatness, in the last step of manufacturing the armature 2, the last step was corrugated in the circumferential direction by press working, and convex portions and concave portions were alternately formed at intervals of 90 °. The maximum height difference between the convex part and the concave part was set to a slight dimension. However, it has been found that simply increasing the flatness of the friction surface 2a as described above cannot completely suppress the generation of vibration and sound, and is insufficient as a measure for preventing vibration and sound.

  For example, an electromagnetic clutch device described in Patent Document 2 is known as a prior art that takes measures to prevent noise. This electromagnetic clutch device is used in an electric power steering device. By using at least one of a driving-side power transmission member and a driven-side power transmission member as a low friction material, the biting between both members is smooth. Therefore, chattering and stick-slip phenomenon are less affected and power can be transmitted smoothly. As the low friction material, an oil-containing sintered material or a member having a friction surface coated with a fluororesin is used.

  If such a low friction material is used to reduce the frictional resistance at the time of relative rotation, it is considered that the generation of sound due to the stick-slip phenomenon can be suppressed to some extent. However, when applied to an electromagnetic clutch used in a vehicle door opening and closing drive device, the oil that oozes out from the oil-containing sintered material is adopted because the rotation sensor and the electronic control device are arranged around the rotor. Scattering and adhering to electronic parts is not preferable because it may cause malfunction.

  On the other hand, when the friction surface is coated with fluororesin, a demagnetizing part is formed on the magnetic circuit of the exciting coil, so the armature's attraction time becomes longer and the operation timing to transmit the motor driving force to the output shaft A new problem arises. For this reason, it is necessary to increase the magnetomotive force of the exciting coil, but this increases power consumption and heat generation. In addition, adding a coating process to the manufacturing process is not preferable because the manufacturing cost increases accordingly, and it becomes impossible to provide it at a low cost.

  As another means for damping the vibration, for example, an electromagnetic clutch described in Patent Document 3 is known. This electromagnetic clutch is used in an image forming apparatus, and viscoelastic members are interposed between a rotor and an armature and between a leaf spring and a gear that elastically support the armature. As the viscoelastic member, foamable EPDM, thermoplastic elastomer, thermoplastic resin, or the like is used. And according to such a structure, the adsorption sound when an armature is magnetically adsorbed by a rotor and the collision sound when an armature collides with a gear by the elastic return force of a leaf | plate spring can be reduced effectively. It is said.

  However, in such an electromagnetic clutch, it is necessary to provide a leaf spring that elastically supports the armature in addition to the viscoelastic member, or it is necessary to form an annular groove for housing the viscoelastic member in the rotor. In addition, there is a problem that the manufacturing cost increases due to an increase in the number of processing steps.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide an electromagnetic coupling device that is inexpensive and can reliably suppress generation of vibration and sound. There is.

  In order to achieve the above object, a first invention comprises a support member, an armature supported by the support member so as to be movable only in the axial direction, and a friction surface facing the friction surface of the armature, A magnetic circuit forming member that is a magnetic circuit of the magnetic circuit member, and a vibration damping member that is interposed between the armature and the support member to bring the friction surface of the armature into contact with the friction surface of the magnetic circuit member, The damping member is formed of a viscoelastic material having a damping function and a vibration damping function, and is interposed between the armature and the support member in a compressed state, and is fixed to the armature. is there.

  2nd invention fixes the said armature and the said damping member with any one of an adhesive agent, a double-sided adhesive tape, or baking.

  In a third aspect of the invention, circumferential frictional machining is applied to the friction surface of the armature.

  In the first invention, since the damping member made of a viscoelastic material having the damping function and the damping function is interposed between the armature and the supporting member, the wave washer is used. Compared to the case, the vibration damping effect due to the stick-slip phenomenon is great, and the generation of sound can be reliably prevented. Moreover, since it is not necessary to use a leaf spring, the number of parts can be reduced, and it can be manufactured and provided at low cost.

  Further, since the vibration damping member is fixed to the armature, it is possible to exert a greater vibration damping effect and vibration damping effect on the armature than when the vibration damping member is fixed to the support member side.

  In the second invention, double-sided pressure-sensitive adhesive tape, adhesive, or baking can be considered as the fixing means, so that it is inexpensive and easy to obtain, and it is not necessary to add any processing to the armature.

  In the third invention, since the flatness of the armature is increased by wave processing, the generation of sound can be further suppressed.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of an electromagnetic coupling device according to the present invention.
The present embodiment shows an example applied to a gapless type electromagnetic clutch used as a power transmission device of a vehicle door opening and closing device, similarly to the electromagnetic clutch shown in FIG. Further, the present embodiment is completely the same except that a vibration damping member made of a viscoelastic material is used instead of the wave washer 5 shown in FIG. For this reason, the same components and parts are denoted by the same reference numerals.

  In FIG. 1, a vehicle door opening / closing device generally designated by reference numeral 20 includes an output shaft 8 rotatably disposed in a housing 12 via a bearing 21, a motor drive shaft 9 not shown, And an electromagnetic clutch 23 provided between the output member 22 and the output member 22. The output member 22 is for transmitting the rotation of the motor to the vehicle sliding door via the output shaft 8, and is fixed to a protruding end portion 8 a protruding from the housing 12 of the output shaft 8. The output member 22 includes an output drum and is wound with a wire (not shown) that opens and closes the slide door.

  The electromagnetic clutch 23 decelerates the rotation of the armature 2 as a driving side rotating member and the rotor 6 as a driven side rotating member, which are disposed opposite to each other on the output shaft 8, and the driving shaft 9 of the motor. The worm wheel 3 as a support member constituting the reduction gear 25 that transmits to the armature 2, the exciting coil 7 that magnetically attracts the armature 2 and the rotor 6, and the magnetic circuit of the exciting coil 7 together with the armature 2 and the rotor 6 are formed. And the field core 26.

  The armature 2 is formed in a disk shape from a magnetic material, and is disposed on the output shaft 8 via a bearing 27 so as to be rotatable and movable in the axial direction. The rotation of the drive shaft 9 is reduced by a reduction gear 25. It is comprised so that it may be transmitted via. The surface of the armature 2 facing the rotor 6 forms a friction surface 2a. The friction surface 2a is subjected to wave machining in order to increase the flatness within a range that does not hinder the frictional engagement with the rotor 6. Wave processing is performed in order to prevent vibration and sound due to the stick-slip phenomenon. By corrugating in the circumferential direction, convex portions and concave portions are alternately formed at intervals of 90 °. The maximum height difference between the convex part and the concave part is a slight dimension.

  The reduction gear 25 includes a worm 10 fixed to the drive shaft 9 and a worm wheel (support member) 3 that meshes with the worm 10. The worm wheel 3 is rotatably disposed on the output shaft 8 via a bearing 27, and the rotation of the worm 10 is decelerated and transmitted to the armature 2, and the armature 2 is supported so as to be movable in the axial direction. is doing. For this reason, a plurality of connecting portions 30 made of protrusions are formed concentrically and integrally on the surface of the worm wheel 3 that faces the armature 2, and the tip portion of the connecting portion 30 is formed in a through hole 31 provided in the armature 2. Each is inserted so that relative sliding is possible. On the other hand, the movement of the worm wheel 3 in the axial direction is restricted by one side surface 27 a of the bearing 27 and the facing surface 3 b of the housing 12. Reference numeral 32 denotes a grease-removal seal member. The grease-removal seal member 32 is fixed in the housing 12 and is interposed in the gap 4 between the armature 2 and the worm wheel 3.

  The rotor 6 is press-fitted to the output shaft 8 so that the friction surface 6 a faces the friction surface 2 a of the armature 2. On the other hand, an annular recess 34 is formed on the surface of the rotor 6 opposite to the friction surface 6 a, and the exciting coil 7 is inserted into the annular recess 34.

  The exciting coil 7 is accommodated in an annular recess 36 of a field core 26 fixed to the inner wall of the housing 12 via a coil bobbin 37, and is inserted into the annular recess 34 of the rotor 6 together with the field core 26. A gap is formed between the inner peripheral surface of the annular recess 34 and the outer peripheral surface of the field core 26, and this field core 26 and the rotor 6 form a magnetic circuit member that becomes a magnetic circuit of the exciting coil 7. ing.

  An annular magnet 40 is fixed to the outer peripheral surface of the rotor 6. The magnet 40 has S poles and N poles alternately formed in the circumferential direction on the surface, and one end portion projects from the friction surface 6 a of the rotor 6 in the axial direction and surrounds the outer periphery of the armature 2. An annular recess 41 is formed on the armature side end surface of the magnet 40. The recess 41 is formed by a recess formed on the outer peripheral surface side of the rotor 6, and the depth is set to be larger than the distance from the armature side end surface of the magnet 40 to the friction surface 6 a of the rotor 6. In other words, the friction surfaces 2 a and 6 a which are friction engagement surfaces between the armature 2 and the rotor 6 face the recess 41. The recess 41 is for receiving wear powder from the armature 2 and the rotor 6 accompanying the operation of the electromagnetic clutch 23 and preventing the powder from being scattered in the housing 12. That is, when the armature 2 and the rotor 6 rotate relative to each other, the friction surfaces 2a and 6a are worn to generate wear powder. The wear powder is attracted by the magnetic force of the magnet 40 and accumulated in the recess 41, thereby preventing scattering into the housing 12.

  A damping member 43 is interposed in the gap 4 formed between the armature 2 and the worm wheel 3. The damping member 43 is formed in a ring shape from a viscoelastic material such as rubber having a damping function and a vibration damping mechanism, for example, an EPDM rubber foam, and has a plate thickness slightly larger than the gap 4 in a natural state. ing. For this reason, the damping member 43 is compressed by the armature 2 when interposed in the gap 4, and by the restoring force, the armature 2 is urged toward the rotor 6 to cause the friction surface 2 a to become the friction surface 6 a of the rotor 6. Pressed. The thickness of the damping member 43 is about 5 mm and is compressed to about 3 to 4 mm. The degree of compression is set by the hardness of the damping member 43 itself and the pressing force for holding the armature 2. The damping member 43 is fixed to the surface of the armature 2 that faces the worm wheel 3 by fixing means. As the fixing means, a double-sided pressure-sensitive adhesive tape, an adhesive, or baking can be considered.

Next, the operation of the electromagnetic clutch 23 having the above structure will be described.
When the electromagnetic clutch 23 is not used, that is, when the sliding door of the vehicle is not automatically opened and closed and the exciting coil 7 is not energized, the armature 2 is applied to the friction surface 6 a of the rotor 6 by the restoring force of the damping member 43. A gapless type electromagnetic clutch is configured by being pressed with a pressing force of.

  When the exciting coil 7 is not excited, the friction surface 2a of the armature 2 and the friction surface 6b of the rotor 6 are in contact with each other. Therefore, when the sliding door as a driven member is manually opened and closed, the output shaft 8 and the rotor 6 Rotate together. On the other hand, the armature 2 does not rotate unless the motor is driven because the reduction gear 25 is the worm 10 and the worm wheel 3. For this reason, relative rotation occurs between the rotor 6 and the armature 2. That is, the rotor 6 performs slip rotation with respect to the armature 2. When the rotor 6 slips and rotates, the armature 2 and the friction surfaces 2a and 6a of the rotor 6 slide, so that a stick-slip phenomenon that causes sound generation occurs.

  In this case, in the present invention, since the damping member 43 made of a viscoelastic material such as rubber is interposed in the gap 4 between the armature 2 and the rotor 6 in a compressed state, the damping function of the damping member 43 is Further, the vibration damping function is larger than that of a conventional metal wave washer, so that the vibration of the armature 2 can be effectively attenuated, and the generation of sound can be reliably suppressed and prevented.

  Further, when the degree of sound generation was examined, in the present embodiment in which the flatness of the friction surface 2a was increased within a range not affecting the frictional engagement between the armature 2 and the rotor 6, the flatness was reduced. It was confirmed that there was little sound generation compared to the case.

  Further, since the damping member 43 is fixed to the armature 2 by the fixing means, it is possible to prevent the generation of sound more reliably. That is, when the damping member 43 is fixed to the worm wheel 3 that is the support member of the armature 2, if the contact state between the armature 2 and the damping member 43 is insufficient, the vibration damping effect is reduced. In the present invention, since the damping member 43 is fixed to the armature 2, the contact state between the armature 2 and the damping member 43 is good, the vibration of the armature 2 is suppressed, Generation | occurrence | production can be prevented effectively.

  Next, when the sliding door is opened and closed while the armature 2 and the rotor 6 are frictionally engaged, the exciting coil 7 is energized to excite it. When the exciting coil 7 is excited, the armature 2 is magnetically attracted to the friction surface 6a of the rotor 6 and the electromagnetic clutch 23 is connected. When the motor is driven in this connected state, the rotation of the drive shaft 9 is decelerated by the worm 10 and the worm wheel 3 and transmitted to the armature 2. For this reason, the armature 2 and the rotor 6 rotate integrally, and the rotation is finally transmitted to the sliding door via the output shaft 8, whereby the sliding door is opened and closed.

  When the sliding door is opened and closed, if a load greater than the frictional engagement force between the armature 2 and the rotor 6 is applied to the sliding door, the rotation of the output shaft 8 and the rotor 6 stops and the frictional engagement between the armature 2 and the rotor 6 occurs. The armature 2 is forcibly released, and the armature 2 slips and rotates with respect to the rotor 6. Accordingly, transmission of power from the motor to the slide door is interrupted, thereby preventing the vehicle door opening / closing device 20 from being damaged. At this time, the armature 2 may vibrate and generate sound. However, as described above, the vibration damping member 43 made of a viscoelastic material is interposed in the gap 4 between the armature 2 and the worm wheel 3, which is likely to occur. There is no.

In the above-described embodiment, the electromagnetic clutch 23 used in the vehicle door opening / closing device 20 has been described. However, the present invention is not limited to this, and the electromagnetic brake in which the armature is magnetically attracted to the field core and the armature is magnetic. The present invention can also be applied to an electromagnetic coupling device that performs power transmission or braking by friction engagement, such as a coil rotation type electromagnetic clutch in which an adsorbed field core is rotated by a slip ring and a brush.
For this reason, in this invention, the magnetic circuit formation member arrange | positioned facing the friction surface of an armature includes what comprises not only a rotor but a field core.

It is sectional drawing which shows one Embodiment which applied this invention to the gapless type electromagnetic clutch used for a vehicle door opening / closing apparatus. It is sectional drawing which shows the conventional gapless type electromagnetic clutch used for the door opening / closing apparatus for vehicles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Armature (drive side rotation member), 3 ... Worm wheel (support member), 4 ... Clearance, 6 ... Rotor (driven side rotation member), 7 ... Excitation coil, 8 ... Output shaft, 9 ... Drive shaft, 10 ... Worm, 23 ... electromagnetic clutch, 43 ... damping member.

Claims (3)

A support member;
An armature supported by the support member so as to be movable only in the axial direction;
A magnetic surface forming member formed with a friction surface opposite to the friction surface of the armature and serving as a magnetic circuit of the exciting coil;
A damping member that is interposed between the armature and the support member to bring the friction surface of the armature into contact with the friction surface of the magnetic circuit member;
The vibration damping member is formed of a viscoelastic material having a vibration damping function and a vibration damping function, and is interposed between the armature and the support member in a compressed state, and is fixed to the armature. An electromagnetic coupling device. The electromagnetic coupling device according to claim 1.
An electromagnetic coupling device, wherein the armature and the damping member are fixed by any one of an adhesive, a double-sided adhesive tape, and baking. The electromagnetic coupling device according to claim 1 or 2,
An electromagnetic coupling device, wherein the friction surface of the armature is subjected to circumferential wave machining.

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