JP2009058058A - Electromagnetic clutch, conveyance roller, and image forming device with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and durable electromagnetic clutch capable of restraining delay of a rotation stop time of a rotor when an armature and the rotor are separated. <P>SOLUTION: This electromagnetic clutch 1 comprises a driving shaft 2, a rotating body 3 having driving force transmission means and rotatably fitted with the driving shaft, a tabular armature 4 engaged with a side of the rotating body 3 to rotate integrally with the rotating body, a rotor 5 fixed to the driving shaft 2 and opposed to a side of the armature 4 separatably, and a coil 8 giving a magnetomotive force between the rotor 5 and the armature 4. In this electromagnetic clutch 1, an armature engagement part for engaging the armature 4 is provided to the rotating body 3, and a rotating body engaging part engaged with the armature engaging part is provided in the armature 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic clutch, a conveyance roller, and an image forming apparatus including the same.

  In general, in an image forming apparatus such as a copying machine, a printer, or a facsimile provided with a paper feeding device, an image is directly or indirectly transferred to a recording paper conveyed by a conveying means such as paper feeding or paper discharge. Forming. In many cases, the conveying means uses a conveying roller utilizing the frictional force of a rubber roller. The rotation and stop of the rubber roller are controlled by a driving device having an electromagnetic clutch.

  As an electromagnetic clutch for an image forming apparatus, for example, a spring type electromagnetic clutch having a structure shown in FIG. 11 is well known as a small electromagnetic clutch applied to such an image forming apparatus. When this electromagnetic clutch is described with reference to FIG. 11, a drive shaft 2 is provided, and a load (not shown) such as a registration roller shaft is connected to an end of the drive shaft 2. A rotating body 3 is rotatably fitted to the outside of the drive shaft 2 and a rotor 5 is fitted so as to rotate integrally with the drive shaft 2. The rotating body 3 is provided with a gear portion and is driven by a motor (not shown). Further, a yoke 6 that supports the coil 8 together with the rotor 5 is rotatably fitted to the drive shaft 2. The yoke 6 can slide and maintain a stationary state even when the drive shaft 2 and the rotor 5 rotate.

  The rotor 5 has an outer cylindrical portion, an inner cylindrical portion, and a connecting portion that connects both cylindrical portions. A hollow disk-shaped armature 4 is disposed at a substantially opposite position between the connecting portion of the rotor 5 and the rotating body 3, and one end of a hollow dish-shaped return spring 49 is fixed to the armature 4. The other end of the return spring 49 is fixed to the rotating body 3. Therefore, the armature 4 is fixed to the rotating body 3 and rotates integrally with the return spring 49 and the rotating body 3. However, the return spring 49 can be finely moved in the axial direction.

  The connecting portion of the rotor 5 is formed with magnetic shielding holes at a plurality of locations along the circumferential direction. These magnetic shielding holes are for securing a magnetic resistance so that a magnetic path to an amateur 4 described later can be easily formed.

  The yoke 6 is composed of a large-diameter cylindrical portion, a small-diameter cylindrical portion, and a bottom plate portion that connects both cylindrical portions, and a magnetic pole in which the coupling portion of the rotor 5 and the armature 4 are opposed to each other surrounded by each portion. A bobbin 7 around which a coil 8 for applying a magnetomotive force to the part is wound is housed.

  Stoppers 9 and 10 are disposed at the left and right ends of the drive shaft 2 so that the rotating body 3, the rotor 5, the yoke 6 and the like do not move in the axial direction on the drive shaft. Reference numeral 81 denotes a lead wire connected to the coil 8. The drive shaft 2 is supported by a bearing (not shown), and the yoke 6 is also supported by a casing or frame of the electromagnetic clutch (not shown).

  In the above configuration, when the coil 7 is energized and excited through the lead wire 81, an attractive force is generated in the magnetic pole portion formed by the facing portion of the connecting portion of the rotor 5 and the armature 4, and the two are coupled. As a result, torque is transmitted from the rotating body 3 driven by a motor (not shown) to the rotor 5 via the return spring 49 and the armature 4, and the drive shaft 2 integrally coupled to the rotor 5 is rotated to rotate outside the figure. Is driven. Note that the yoke 6, the coil 8, and the bobbin 7 are slipped and kept stationary even when the rotor 5 and the drive shaft 2 are rotated.

  A magnetic path when the coil 8 is energized is formed around the coil 8, and the large diameter cylindrical portion of the yoke 6 → the outer cylindrical portion of the rotor 5 → the connecting portion of the rotor 5 → the armature 4 → the connecting portion of the rotor 5 → The inner cylindrical portion of the rotor 5 → the outer peripheral portion of the drive shaft 2 → the small diameter cylindrical portion of the yoke 6 → the bottom plate portion of the yoke 5 → the large diameter cylindrical portion of the yoke 5. Then, electromagnetic coupling is formed between the rotor 5 and the armature 4, and the rotor 5 and the armature 4 are in close contact with each other against the spring force of the return spring 49.

  When the coil 8 is turned off and demagnetized, the electromagnetic coupling between the armature 4 and the rotor 5 is released, the armature 5 returns to the rotating body 3 side by the spring force of the return spring 49, and the armature 4 and the rotor 5 are connected. The torque transmission from the armature 4 to the rotor 5 is interrupted.

  Patent Document 1 discloses an electromagnetic clutch that eliminates variations in electromagnetic coupling force between the rotor 5 and the armature 4 and enables stable coupling and separation between the rotor 5 and the armature 4. This electromagnetic clutch forms a magnetic path that goes around the rotor, the hub rotor, the shell, and the rotor by covering the coil with a shell and sandwiching the coil between the rotor and a hub rotor fixed to the drive shaft. The magnetic path from the hub rotor to the shell is set in the thrust direction of the drive shaft, and the gap is reduced to stabilize the magnetic force.

  Patent Document 2 discloses an electromagnetic clutch that does not use a spring. 12 and 13 are a sectional view and an exploded perspective view of the electromagnetic clutch. With respect to this electromagnetic clutch, parts having the same functions as those in FIG. The drive shaft 2, the rotor 5, the yoke 6, the bobbin 7, and the coil 8 are substantially the same as the electromagnetic clutch shown in FIG. In this electromagnetic clutch, the armature 4 is not provided with a spring. The disk-shaped armature 4 is provided with a plurality of protrusions 45 at the periphery. The protrusion 45 has two legs protruding perpendicularly to the disk-shaped surface. On the other hand, on the surface of the rotating body 3 facing the amateur 4, a leg of the protrusion 45 is accommodated, and a locking portion for rotating the armature 4 integrally with the rotating body 3 is provided.

  The amateur 4 is arranged in a space formed by the rotating body 3 and the rotor 5 and can be finely moved in the direction of the drive shaft. For this reason, when an electric current flows through the coil 8, the magnetic force works and the armature 4 is attracted to the rotor 5 side and comes into close contact with the rotor 5. When the amateur 4 and the rotor 5 are in close contact with each other, the driving force of the rotating body 3 is transmitted to the rotor 5 through the amateur 4 and the rotor 5 also rotates. Since the rotor 5 is fixed to the drive shaft, the rotation of the rotating body 3 is finally transmitted to the drive shaft 2. When the current of the coil 8 is interrupted, the contact force between the armature 4 and the rotor 5 is lost, and the rotor 5, that is, the drive shaft 2 is not driven. Here, in order to ensure the separation between the armature 4 and the rotor 5, a device for giving the spring force by making the armature 4 or the rotor 5 corrugated instead of a flat surface or by making it into a dish shape is disclosed. .

Such an electromagnetic clutch does not require a spring, has a merit that the number of parts is reduced and the size can be reduced. Also, the use of a spring as a fatigue component has a positive effect on the life and reliability of the electromagnetic clutch.
JP 2006-258229 A JP 2006-170231 A

  The electromagnetic clutch described in Patent Document 2 is superior to the conventional spring-type electromagnetic clutch. However, when the armature 4 and the rotor 5 are coupled, the projection 45 of the armature 4 and the locking portion 35 of the rotating body 3 are used. It is easy to be shocked between. For this reason, the armature 4 may be cracked, or the portion of the locking portion 35 of the rotating body 3 that is in contact with the foot of the projection 45 of the armature 4 may be damaged or worn. For example, at the moment when the armature 4 and the rotor 5 are coupled and the armature 4 is added, the foot of the protrusion 45 hits the side wall 34 on the rear side in the rotation direction of the rotating body 3 of the locking portion 35 of the rotating body 3. 34 is damaged or worn. If this operation is repeated for a long period of time, the side wall 34 is greatly damaged and a damaged portion 35a is formed. Then, the engagement state of the engagement portion 35 of the rotating body 3 and the projection 45 of the armature 4 as shown in FIG. 14A is the engagement portion 35 as shown in FIG. 14B. Spreads and the feet of the protrusion 45 ride on the damaged portion 35a. If the coil power supply is cut off in such a state and the contact between the armature 4 and the rotor 5 is released, the feet of the protrusions 45 are difficult to move to the back side of the locking portion 35. 4 and the rotor 5 remain in close contact with each other, and the separation becomes insufficient. If the amateur 4 and the rotor 5 are not sufficiently separated from each other, the frictional force between the amateur 4 and the rotor 5 remains, and the rotor 5 may be rotated around the amateur 4. In this way, the stop time of the rotor 5 is delayed.

  When the change in the delay time was confirmed by an endurance test, a result as shown in FIG. 15 was obtained. FIG. 15 is a graph plotting the stop delay time of the rotor 5, that is, the roller when the rotation stop is repeated 2 million times for the above-described four electromagnetic clutches of the same type. As can be seen from FIG. 15, the initial stop delay time of the four electromagnetic clutches was about 7 ms, but became 11 to 14 ms when operated 1 million times, and 12 to 15 ms when operated 2 million times.

  Such a delay in stopping the electromagnetic clutch is a problem when determining the recording paper conveyance position of the image forming apparatus, and is an important problem for accurate printing. In particular, the higher the speed of printing, the greater the misalignment, and the more easily the breakage and wear of the locking portion 35 occur.

  An object of the present invention is based on the above-described problems, and is an electromagnetic clutch that is small and durable, and that suppresses a delay in the rotation stop time of the rotor when the armature and the rotor are separated from each other, and a transport roller including the electromagnetic clutch. An image forming apparatus is provided.

In order to solve the above problems, the present inventors have completed the following invention.
The present invention relates to a drive shaft, a rotating body having a driving force transmission means and rotatably fitted to the drive shaft, and a flat armature engaged with the side surface of the rotating body so as to rotate integrally with the rotating body. An electromagnetic clutch including a rotor fixed to the drive shaft and arranged to face the side surface of the amateur so as to be detachable, and a coil for giving a magnetomotive force between the rotor and the amateur, The electromagnetic clutch is characterized in that an armature engaging portion that engages an amateur is provided, and the armature is provided with a rotating body engaging portion that engages with the armature engaging portion.

  In a preferred aspect of the present invention, the side surface of the armature engaging portion that contacts the armature when the rotating body rotates and the side surface of the rotating body engaging portion that contacts the side surface are in surface contact. The electromagnetic clutch.

  In a preferred aspect of the present invention, the side surface that contacts the armature and transmits the driving force when the rotating body rotates in the armature engaging portion is inclined rearward in the rotating direction of the rotating body as the distance from the rotor side increases. It is an electromagnetic clutch.

  In a preferred aspect of the present invention, the electromagnetic clutch is characterized in that a groove is formed on the side opposite to the rotor side of the side surface that contacts the armature and transmits the driving force when the rotating body rotates in the armature engaging portion.

  In a preferred aspect of the present invention, the electromagnetic clutch is characterized in that the rotor and the armature are formed of a member containing a soft magnetic material.

  In a preferred aspect of the present invention, the rotor and the armature are provided with a portion magnetized so as to repel each other when not magnetized by the coil.

  Preferably, in the electromagnetic clutch according to the present invention, at least one of the rotating body and the armature includes a portion magnetized so as to attract each other when the armature is not magnetized by the coil.

  The present invention is the transport roller characterized in that a roller is disposed on the drive shaft of the electromagnetic clutch.

  The present invention is an image forming apparatus including the transport roller.

  According to the present invention, there is provided an electromagnetic clutch that is small and durable, and that suppresses a delay in the rotation stop time of the rotor when the amateur and the rotor are separated from each other, and a conveyance roller and an image forming apparatus including the electromagnetic clutch. be able to.

  The best mode for carrying out the present invention will be described with reference to the drawings as necessary. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of a preferred embodiment of the present invention, and does not limit the scope of the claims.

(Embodiment 1)
The electromagnetic clutch of Embodiment 1 which concerns on this invention is shown in sectional drawing 1 and exploded perspective view 2. FIG. The electromagnetic clutch 1 includes a drive shaft 2, a rotating body 3, an armature 4, a rotor 5, a yoke 6, a bobbin 7, and a coil 8 as main components, and in addition, stoppers 9 and 10 and a sliding member 11. , 12 and so on. In addition, this electromagnetic clutch 1 is not provided with the return spring like the conventional spring type electromagnetic clutch.

  The configuration of the electromagnetic clutch will be briefly described with reference to FIGS. 1 and 2. A rotating body 3 having a gear on the drive shaft 2 is rotatably fitted, and an armature 4 is attached to a side surface of the rotating body 3. Is fitted so as to rotate integrally with the rotating body 3 via the engaging portion. The armature 4 cannot be freely rotated in the rotation direction by the engagement of the armature engaging portion (the locking portion 35 in this embodiment) and the rotating body engaging portion (the protrusion 41 in this embodiment), but the drive shaft 2 It can move in the axial direction. A rotor 5 is disposed on the opposite side of the armature 4 to the rotating body 3 so as to face the opposite surface, and the rotor 5 is fixed to the drive shaft 2. A yoke 6 that supports the bobbin 7 around which the coil 8 is wound is disposed on the opposite side of the rotor 5 from the rotating body 3. The yoke 6 is rotatably fitted to the drive shaft 2. The rotary body 3 and the yoke 6 are restricted from moving in the axial direction of the drive shaft 2 by stoppers 9 and 10 disposed on both sides of the drive shaft 2.

  Each component will be described with reference to FIGS. The drive shaft 2 is usually a hollow cylinder and is supported by a bearing (not shown). When this electromagnetic clutch is used in an image forming apparatus, a load such as a shaft of a conveyance roller is coupled. Further, a flange 13 projecting radially outward is formed at an intermediate position in the axial direction of the drive shaft 2. The flange 13 fixes the rotor 5 described later to the drive shaft 2, and the rotating body 3 It also serves as a stopper that does not move in the axial direction of the drive shaft 2.

  The rotating body 3 includes a synthetic resin molded product and a metal gear portion 31, is rotatably fitted to the outside of the drive shaft 2, and is given a driving force by a motor and a gear (not shown). On the side surface of the gear portion 31, a crown-shaped cap portion 36 is provided, and a locking portion 35 that locks a projection 41 of an armature 4 to be described later is formed on the outer periphery of the inner bottom surface 32 of the cap portion 36. The number of the locking portions 35 is adjusted to the number of the projections 41 of the amateur 4 and six in the example of this embodiment.

  The amateur 4 is slidably disposed along the axial direction of the drive shaft 2 in the space surrounded by the rotating body 3 and the rotor 5. The amateur 4 has a flat plate shape and a ring shape. On the outer periphery of the amateur 4, planar protrusions 41 are formed at a plurality of locations along the circumferential direction. And this protrusion 41 is engaged with the above-mentioned latching | locking part 35 provided in the rotary body 3. FIG. Accordingly, the armature 5 is locked to the locking portion 35 of the rotating body 2 and rotates integrally with the rotating body 3. However, the armature 5 is not locked by the locking portion 35 with respect to the movement of the drive shaft 2 in the axial direction, and slides along the axial direction of the drive shaft 2 on the side surface of the rotor 5 described later. It can be closely attached or separated. In addition, the armature 4 has magnetic shielding holes 42 formed at a plurality of locations (three locations in the present embodiment) along the circumferential direction of the ring, and the magnetic shielding holes 42 are connected by ribs.

  The rotor 5 includes a cylindrical portion 53, a reduced diameter portion that is reduced in diameter radially inward from the cylindrical portion 53, and a flat portion 51 that connects the cylindrical portion 53 and the reduced diameter portion. Have And in the plane part 51, the magnetic shielding holes 52 formed twice in the radial direction are provided at a plurality of locations along the circumferential direction (three in this embodiment, a total of six magnetic shielding holes), The magnetic shielding holes 52 are connected by ribs. The magnetic shielding holes 52 of the rotor 5 and the magnetic shielding holes 42 of the armature 4 are formed so as to be displaced in the radial direction when arranged opposite to each other. For this reason, in the part which the rotor 5 and the armature 4 oppose, there are four magnetic pole parts. It is also possible to adopt a configuration in which the number of poles is changed by changing the number of magnetic shielding holes of the rotor 5 and the armature 4. The reduced diameter portion is seated on the flange 13 of the drive shaft 2. A locking portion that engages with a protrusion formed on the drive shaft 2 is provided at the inner peripheral end of the reduced diameter portion, and both are engaged. For this reason, the rotor 5 and the drive shaft 2 rotate integrally. It should be noted that recesses are provided at a plurality of locations along the circumferential direction of the flange 13 of the drive shaft 2, and a protrusion that engages with the recesses is provided at the inner peripheral end of the rotor 5 so that both are engaged. Is possible.

  The yoke 6 has a cap shape composed of a large-diameter cylindrical portion, a small-diameter cylindrical portion, and a bottom plate portion connecting the two, like a conventional spring type electromagnetic clutch, and a coil 8 is provided inside the cap. A wound bobbin 7 is stored. The yoke 6 is rotatably fitted to the drive shaft 2 and is supported by a casing or frame of an electromagnetic clutch (not shown) via a support member 71. Reference numeral 81 represents a lead wire serving as a terminal of the coil 8. Sliding members 11 and 12 are disposed between the yoke 6 and the stopper 10 and the drive shaft 2 so that even if the drive shaft 2 and the rotor 5 rotate, the sliding is improved and the yoke 6 is stationary. Can be easily maintained.

  A soft magnetic material is preferably used for each magnetic path forming portion of the drive shaft 2, the armature 4, the rotor 5, and the yoke 6. In particular, since the amateur 4 and the rotor 5 need to be in close contact with each other by magnetic force, it is particularly preferable to use a high-performance soft magnetic material. In addition, when a soft magnetic material is used for the magnetic path forming portions such as the rotor 5, the armature 4, and the yoke 6, a material having a small coercive force with reduced processing strain may be used so that no residual magnetic flux exists after demagnetization. preferable. In order to eliminate this processing distortion, a conventionally known steam treatment or annealing treatment may be performed. In the electromagnetic clutch of this embodiment, a soft magnetic material is used for each of the magnetic path forming members of the drive shaft 2, the armature 4, the rotor 5, and the yoke 6, and the coercive force reduction such as annealing or steam treatment is performed as necessary. Processing is performed to reduce the residual magnetic flux in the magnetic path to reduce the residual attractive force. As the soft magnetic material, for example, a non-oriented electrical steel sheet (JIS C2552) or electromagnetic soft iron (JIS C2504) is applied. When the coil power supply is shut off and demagnetized by the coercive force lowering process, the magnetic pole portion at the opposite portion of the armature 4 and the rotor 5 is immediately demagnetized, the attraction force is lost, and torque transmission from the armature 4 to the rotor 5 is stopped. The rotation of the load roller or the like coupled to the drive shaft 2 is immediately stopped.

  When the residual magnetic flux is small, there is no attractive force when the coil power supply is cut off, so that the attractive gap on the contact surface between the rotor 5 and the armature 4 can be set very small. That is, since the thrust gap, which is the axial gap of the drive shaft 2 when the armature 4 is interposed between the rotor 5 and the rotating body 3, can be set very small, the amount of movement of the armature 4 in the axial direction can be made minute. . As a result, an extra time loss when the armature 4 moves in the axial direction is omitted, the torque transmission start delay time and the torque release delay time are both shortened, and the response of the clutch is improved. Moreover, since the amount of movement of the armature 4 in the axial direction is very small, an impact sound that is generated when the rotor 5 and the armature 4 are attracted during excitation, and an impact that occurs when the armature 4 moves away from the rotor 5 during demagnetization. Both sounds can be reduced. Furthermore, not only the conventional return spring is not used, but the armature 4 is a single flat plate, so that the entire length of the electromagnetic clutch in the axial direction can be shortened and the size can be reduced.

  The operation of this electromagnetic clutch will be described. FIG. 3 conceptually shows a magnetic path during operation of the electromagnetic clutch. When a current is passed through the coil 8 to generate a magnetic force, the magnetic path is connected from the small-diameter cylindrical portion of the yoke 6 at the center of the coil to the bottom plate portion and the large-diameter cylindrical portion (also serving as the shell portion of the coil). Furthermore, it returns from the peripheral part of the rotor 5 to the small diameter cylindrical part of the yoke 6 through the armature 4 and the inner peripheral part of the rotor 5. At this time, the rotor 5 and the armature 4 are magnetized, the armature 4 is attracted to the rotor 5, moves to the rotor 5 side along the axial direction, and the rotor 5 and the armature 4 come into close contact with each other. When the armature 4 is rotated integrally with the rotating body 3 driven by a motor (not shown) in this closely contacted and sucked state, the rotor 5 is also rotated by the frictional force of the contact portion with the armature 4. . If the rotor 5 rotates, the drive shaft 2 fixed to the rotor 5 rotates. In this way, the driving force of the rotating body 3 is transmitted to the drive shaft 2. Further, the drive shaft 2 rotates and a load such as a transport roller (not shown) connected to the drive shaft 2 is driven. The yoke 6, the bobbin 7, and the coil 8 are supported by a casing of an electromagnetic clutch and the like, and even if the rotor 5 and the drive shaft 2 rotate, the yoke 6, the bobbin 7, and the coil 8 are caused to slip by sliding with the sliding members 11, 12 and the like. Maintain state.

  In this case, the distance that the armature 4 moves along the axial direction is small, and since the conventional return spring is not used, it is necessary to overcome the spring force and connect the armature 5 to the rotor 3. For this reason, the movement time of the armature 4 is shortened, and the response of starting torque transmission from the rotating body 3 to the drive shaft 2 is enhanced. In addition, since the response time for starting torque transmission does not vary due to variations in the spring force of the return spring, the torque transmission time is stabilized.

  On the other hand, when the power source of the coil 8 is cut off, the magnetic force formed between the rotor 5 and the amateur 4 is lost, and the attractive force between the rotor 5 and the amateur 4 is lost. Since the amateur 4 is movable in the axial direction of the drive shaft 2, if the attractive force acting between the rotor 5 and the amateur 4 disappears, the rotational direction between the rotor 5 and the amateur 4 The frictional force with respect to is almost lost, and the rotation of the armature 4 is not transmitted to the rotor 5. The rotor 5 and the drive shaft 2 fixed to the rotor 5 stop rotating.

  In order to assemble the electromagnetic clutch of this embodiment, the rotor 5 is inserted into one end side (right side in FIG. 1) of the drive shaft 2, and the reduced diameter portion of the rotor 5 is seated on the flange 13. Next, the armature 4 and the rotating body 3 are inserted into the drive shaft 2 so as to cover the rotor 5 with the projection 41 of the armature 4 engaged with the locking portion 35 of the rotating body 3. Subsequently, the stopper 9 is inserted into one end side of the drive shaft 2, and the position of the rotor 5, the armature 4, and the rotating body 3 in the axial direction is restricted with the flange 13.

  Further, the bobbin 7, the yoke 6, the sliding members 11, 12, and the stopper 10 are sequentially inserted into the other end side (left side in FIG. 1) of the drive shaft 2, and the bobbin 7 is interposed between the stopper 10 and the flange portion 13. The position of the yoke 6 is restricted in the axial direction.

  When the stopper 9 is inserted into one end side (right side in FIG. 1) of the drive shaft 2 and the stopper 9 is inserted too far toward the flange 13, the ring portion of the armature 4 is connected to the connecting portion 51 between the rotating body 3 and the rotor 5. And cannot be moved in the axial direction to serve as a clutch. For this reason, it is necessary to ensure a slight thrust gap between the ring portions of the armature 4 so that they can move between the connecting portion 51 of the rotor 3 and the rotating body 3. In addition, when the rotating body 3 is a resin molded product, expansion due to temperature rise is large, so it is necessary to secure a thrust gap from this point.

(Embodiment 2)
As the second embodiment, there is an electromagnetic clutch obtained by changing the shape of the electromagnetic clutch armature of the first embodiment. FIG. 4A shows an amateur shape of the electromagnetic clutch of the first embodiment. On the other hand, FIG.4 (b) has shown the shape of the amateur of the electromagnetic clutch of Embodiment 2. FIG. The amateur 4 may be a rotating body engaging portion of any shape as long as it is flat. As shown in FIG. 4B, the armature rotating body engaging portion of this form is a locking hole 46. The locking hole 46 is a circular hole in the figure, but may have any shape such as an ellipse, a rectangle, or a hexagon. Although not shown in the drawings, the armature engaging portion formed on the rotating body 3 becomes a protrusion that engages the armature 4 with the engaging hole 46 and engages the armature 4. Also in this case, if the armature 4 is engaged with the rotating body 3, the armature 4 rotates integrally with the rotating body 3 and can move in the drive shaft direction (thrust direction) of the drive shaft 2. The second embodiment is the same as the first embodiment except for the engagement portion between the armature 4 and the rotating body 3, and the operation and action thereof are also the same. As described above, the armature 4 in the electromagnetic clutch 1 of the present invention has a structure in which the strength of the rotating body engaging portion is sufficiently provided by being a flat plate and having a large degree of freedom in the shape of the rotating body engaging portion. In addition, it is easy to make a structure that is durable against damage due to repeated stress of the amateur 4. Furthermore, by making the armature 4 into a flat plate, the interval between the rotating body 3 and the rotor 5 can be narrowed, and the size and weight of the entire electromagnetic clutch 1 can be suppressed.

(Embodiment 3)
The electromagnetic clutch of the third embodiment is also characterized by the engaging portion between the rotating body 3 and the amateur 4. As shown in FIG. 5, the electromagnetic clutch of this embodiment is in contact with the side surface 34 a that transmits the driving force by contacting the armature 4 when the rotating body 3 rotates in the armature engaging portion 35 of the rotating body 3 and the side surface 34 a. The side surface 41a of the rotating body engaging portion 41 is in surface contact. This electromagnetic clutch is the same as the electromagnetic clutch of Embodiment 1 or 2 except for the above points. As already described, a strong stress is applied to the side surface 34 a of the armature engaging portion 35 and the side surface 41 a of the rotating body engaging portion 41 at the start of transmission of the driving force to the rotor 5. For this reason, as shown in FIG. 13, the conventional electromagnetic clutch was a part where the wear was severe. Also in the electromagnetic clutch of the present invention, a strong stress is applied to this portion at the start of driving force transmission. Therefore, the stress is distributed by bringing the side surface to which this strong stress is applied into surface contact. As a result, the wear of the side surfaces 34a and 41a is reduced, and the delay of the stop time as shown in FIG.

(Embodiment 4)
In the electromagnetic clutch according to the fourth embodiment, the side surface 34a that contacts the armature and transmits the driving force when the rotating body 3 rotates in the armature engaging portion 35 moves backward in the rotating direction of the rotating body 3 as it moves away from the rotor 5 side. The side surface 34a is inclined so as to face the rotating body 3 side. As shown in FIG. 6, the side surface 34 a of the armature engaging portion 35 of the rotating body 3 is inclined by more than 90 ° so as to face the back side of the armature engaging portion 35. The rotation direction of the rotator 3 is assumed to be rotating as indicated by the arrow pointing to the right in FIG. 6. When the rotator 3 is rotated, the armature 4 is in contact with the side surface 34 a and pushed in the rotation direction. It is rotated. In this case, a downward force always acts on the amateur 4. In other words, the armature 4 is exerted with force in the direction away from the rotor engaging portion 35, in other words, away from the rotor 5. This force has the same effect as the spring stress of the spring type electromagnetic clutch, and when the power of the coil 8 is cut off and the attractive force due to the magnetic force disappears between the rotor 5 and the armature 4, the rotor 5 and the armature are instantaneously 4 is separated. Thereby, the delay time of the drive shaft 2 stop at the time of interrupting | blocking the power supply of the coil 8 can be shortened.

  Note that the inclination angle of the side surface 34a takes into consideration the rotational speed of the rotating body 3, the strength of the load associated with the electromagnetic clutch, the rotational resistance of the armature 4 when rotating while the clutch is disconnected, and the like. Is preferably determined. If the side surface 34a has a small inclination and is close to vertical, the armature 4 receives only a small downward stress in FIG. 7, and the rotor 5 and the armature 4 are not greatly separated from each other when the magnetic force is interrupted. However, the coupling force at the time of clutch coupling between the rotor 5 and the amateur 4 is hardly weakened. On the contrary, when the side surface 34a has a large inclination, for example, the inclination angle is 60 °, and the side surface 34a is close to the parallel to the bottom surface of the armature engaging portion 35, the mature 4 has a large downward stress. Therefore, there is a possibility that the coupling force at the time of clutch engagement is weakened and sufficient driving force transmission cannot be performed. Usually, when the power of the coil 8 is shut off, the smallest inclination (the side surface 34a is nearly perpendicular to the rotation direction of the rotating body 3) among the inclinations at which the armature 4 can be immediately separated from the rotor 5 is set. preferable. In this embodiment, the other points are the same as already described. Note that the electromagnetic clutch combining the third and fourth embodiments has an inclination angle so that the side surface 41a of the rotating body engaging portion 41 is in surface contact with the side surface 34a. This is also an excellent form in terms of shortening the delay time.

(Embodiment 5)
In the electromagnetic clutch of the fifth embodiment, a groove is formed on the side opposite to the rotor side of the side surface 34a that contacts the armature 4 and transmits the driving force when the rotating body 3 rotates in the armature engaging portion 35. As shown in FIG. 7, a groove 35 a is formed in the back of the side surface 34 a of the armature engaging portion 35. This groove has no effect while the electromagnetic clutch is new. However, when used for a long period of time, as described above, the side surface 34a of the armature engaging portion 35 is worn as shown in FIG. At this time, in the conventional electromagnetic clutch, as shown in FIG. 14B, the rotating body engaging portion 41 is in a state of riding on the wear portion 35 (a), and the armature 4 when the clutch is disengaged There is a risk of preventing the rotor 5 from being separated. In the electromagnetic clutch of this form, since the groove 35a is formed in the back of the side surface 34a of the armature engaging portion 35, the opening side of the side surface 34a of the armature engaging portion 35 is worn as shown in FIG. However, since there is the groove 35a, it is difficult to make a step on the worn side wall 34b so that the rotating body coupling portion 41 rides up. For this reason, the trouble described with reference to FIG. 14 does not occur. The electromagnetic clutch of this embodiment is the same as the electromagnetic clutch of the embodiment described so far except for the points described above.

(Embodiment 6)
The electromagnetic clutch of the sixth embodiment includes a portion where the rotor and the armature are magnetized so as to repel each other when not magnetized by the coil. As shown in FIG. 9A, the electromagnetic clutch of this embodiment has magnetic forces that repel each other on at least part of the surfaces of the armature 4 and the rotor 5 that face each other. This is because the armature 4 and the rotor 5 are magnetized so as to have a holding force, respectively, and when they are not magnetized by the coil 8, they are repelled by their respective magnetic forces. If it does so, the armature 4 and the rotor 5 will repel each other at the same time as the coil power supply is shut off. This repulsive force is much weaker than the attractive force due to the magnetization of the mature 4 and the rotor 5 by the coil. In addition, as shown in FIG.9 (b), a permanent magnet can be used only for the armature 4 and a part of rotor 5, and the repulsive force of this permanent magnet can also be utilized. The electromagnetic clutch of this embodiment is the same as the electromagnetic clutch of the embodiment described so far except for the points described above.

(Embodiment 7)
In the electromagnetic clutch of the seventh embodiment, at least one of the rotating body and the armature includes a portion that is magnetized to attract each other when the armature is not magnetized by the coil. In FIG. 10, the rotary body and amateur of the electromagnetic clutch of this embodiment are shown. The rotating body and the armature shown in FIG. 10 (a) magnetize the entire rotating body 3 and the armature 4 so that the magnetic poles of the opposing surface 32 and the opposing surface 45 are reversed as in S and N, for example. To do. If it does so, the rotary body 3 and the armature 4 will produce the attraction | suction force, and will exhibit the same effect as the spring of a spring type electromagnetic clutch. The rotating body 3 and the armature 4 shown in FIG. 10B give an attractive force to the armature 4 that is a soft magnetic material using only the outer peripheral portion of the rotating body 3 as a magnetic material. Since the distance between the facing surface 32 and the facing surface 45 is small, the rotor 3 attracts the armature 4 when the armature 4 and the rotor 5 (not shown) are not attracted by the strong magnetomotive force of the coil 8. The electromagnetic clutch of this embodiment is the same as the electromagnetic clutch of the embodiment described so far except for the points described above.

(Embodiment 8)
The eighth embodiment is a transport roller including any one of the electromagnetic clutches described in the first to seventh embodiments. In this conveying roller, the roller shaft is coupled to the end of the drive shaft 2 of the electromagnetic clutch, and a conveying portion having an appropriate frictional force and elasticity made of rubber or resin is formed on the outer peripheral portion of the roller. . In this manner, the driving force of the drive shaft 2 can be reliably transmitted to the roller transport section, and transported objects such as recording paper can be transported. The conveyance roller of this form is a conveyance roller for recording paper or the like used in an image forming apparatus or the like, and can convey the recording paper or the like at an accurate speed and can start or stop conveyance at an accurate timing. Due to such characteristics, the transport roller can be used particularly suitably for a registration roller, a paper feed roller, a paper discharge roller, and the like that need to accurately control the timing of transport and stop of recording paper or the like in the image forming apparatus.

  Examples of the image forming apparatus provided with the conveying roller include an electrophotographic copying machine, a printer, a facsimile, and a complex machine that combines these functions. Furthermore, the present invention can also be used for an image forming apparatus that requires a paper transport roller of a printing apparatus such as an inkjet printer or a conventional screen printing or letterpress printing.

Sectional drawing of the electromagnetic clutch which concerns on this invention 1 is an exploded perspective view of the electromagnetic clutch shown in FIG. Magnetic path conceptual diagram during electromagnetic clutch operation Example of electromagnetic clutch amateur according to the present invention FIG. 4 is an engagement diagram of a locking portion of a rotating body of an electromagnetic clutch according to the present invention and an armature projection. Engagement diagram of side of locking part of inclined rotating body and projection of amateur Engagement diagram of improved rotor side and side projection Engagement diagram of the locking member side surface of the rotating body and the armature projection when the locking portion side surface is worn Conceptual diagram of magnetized state of rotor and amateur Conceptual diagram of magnetization state of rotating body and amateur Cross section of spring type electromagnetic clutch Cross section of an improved conventional electromagnetic clutch 12 is an exploded perspective view of the electromagnetic clutch shown in FIG. Engagement diagram of engaging part of rotating body and projection of amateur Change of stop time in endurance test

Explanation of symbols

1: Electromagnetic clutch 2: Drive shaft 3: Rotating body 4: Amateur 5: Rotor 6: Yoke 7: Bobbin 8: Coil 9, 10: Stopper 11, 12: Sliding member 31: Gear portion 32: Armature of the rotating body Opposing surface 34a facing the plane: Side surface 34b for transmitting the driving force of the rotating body to the amateur: Wear portion 35 on the side surface 34a: Locking portion (amateur engaging portion)
35a: Groove 37: Outer peripheral portion 41 of the rotating body: Protrusion (rotating body engaging portion)
41a: Side surface 43 of the rotating body engaging portion in contact with the side surface 34a: Opposing surface 44 facing the rotor of the amateur 45: Outer peripheral portion 45: facing surface facing the rotating body of the arm 46: Locking hole 49: Return spring 54: Rotor The opposite side facing the amateur

Claims (9)

A drive shaft;
A rotating body having a driving force transmission means and rotatably fitted to the driving shaft;
A flat armature engaged on the side surface of the rotating body so as to rotate integrally with the rotating body;
A rotor fixed to the drive shaft and disposed so as to be detachably opposed to the side surface of the amateur;
An electromagnetic clutch comprising a coil for applying a magnetomotive force between the rotor and the amateur,
The rotating body is provided with an amateur engaging portion that engages an amateur,
The electromagnetic clutch according to claim 1, wherein the armature is provided with a rotating body engaging portion that engages with the armature engaging portion.   The side surface that contacts the armature and transmits the driving force when the rotating body rotates in the armature engaging portion, and the side surface of the rotating body engaging portion that contacts the side surface are in surface contact. The electromagnetic clutch as described in.   The side surface which transmits a driving force in contact with the armature when the rotating body rotates in the armature engaging portion is inclined rearward in the rotational direction of the rotating body as it moves away from the rotor side. The electromagnetic clutch described.   The groove | channel is formed in the opposite side to the rotor side of the side surface which contact | connects an amateur at the time of rotation of the rotary body in the said armature engaging part, and transmits a driving force, It is any one of Claims 1-3 characterized by the above-mentioned. The electromagnetic clutch described.   The electromagnetic clutch according to any one of claims 1 to 4, wherein the rotor and the armature are formed of a member containing a soft magnetic material.   The electromagnetic clutch according to any one of claims 1 to 5, wherein the rotor and the armature include a portion magnetized so as to repel each other when not magnetized by the coil.   The at least one of the rotating body and the armature includes a portion magnetized to attract each other when the armature is not magnetized by the coil. The electromagnetic clutch described.   A conveying roller, wherein a roller is disposed on the drive shaft of the electromagnetic clutch according to claim 1.   An image forming apparatus comprising the conveyance roller according to claim 8.

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