JP2002048151A - Electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic clutch which is small-sized, inexpensive, has superior durability, and can simplify an assembly process. SOLUTION: The electromagnetic clutch comprises a shaft 13 rotatable about its axis and provided at least with magnetic substance body 15, a gear 17 and a rotor 16 outwardly engaged with the shaft 13, an excitation coil part 12 outwardly engaged with the shaft 13 and provided with a protrusion 21 on the surface thereof, and a field 11 surrounding the excitation coil part 12, wherein the field 11 has a recess 114 engaged with the protrusion 21 formed on the surface of the excitation coil part 12 and is formed not to contact with the magnetic substance body 15 of the shaft 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch which electrically connects a shaft rotatable around an axis and an input-side rotating body rotatably fitted to the shaft.

[0002]

2. Description of the Related Art Recently, information industry equipment such as copiers and printers have been increasingly reduced in size and cost, and electromagnetic clutches, which are components thereof, are required to be small, inexpensive, and hard to cause failure. It has become.

Conventionally, this type of electromagnetic clutch is, for example,
It is configured as shown in FIG. This electromagnetic clutch is applied to a paper feeding mechanism of a copying machine or the like, and includes a field 51 formed of a double-bottomed cylindrical body having a tubular fitting portion 50 at the center, and a fitting portion in the field 51. A ring-shaped exciting coil portion 52 externally fitted to the
And a shaft 53 rotatably penetrated therethrough.
The shaft 53 has a slit-shaped through hole 5 in the circumferential direction.
The rotor 55 formed with 4 is externally fitted and fixed at a position close to the exciting coil section 52.

A gear 56 to which a rotational force is applied from the outside is rotatably fitted at a position on the opposite side of the excitation coil portion 52 across the rotor 55 of the shaft 53, and is opposed to the rotor 55 of the gear 56. The armature 57 is attached to the side to be connected via a leaf spring 58.

At both ends of the shaft 53, locking ring grooves 61, 62 are formed, and the ring-shaped locking members 63, 64 are fitted therein so that the field 51 and the gear 56 do not come off the shaft 53. It has become. Note that among these components, at least the field 51 (including the fitting portion 50), the shaft 53, the rotor 55, and the armature 57 are made of a magnetic material such as an iron-based metal.

In the electromagnetic clutch constructed as described above,
When the excitation coil section 52 is energized, the field 51 (including the fitting section 50) made of a magnetic material, the shaft 5
3. Magnetic fluxes M1 and M around rotor 55 and armature 57
2 are formed. The armature 57 is a leaf spring 58
As a result, the rotation of the gear 56 is transmitted to the rotor 55 to rotate the shaft 53 (FIG. 7B). Further, when the power supply to the excitation coil section 52 is cut off, the magnetic flux disappears, the magnetic attraction to the arches 57 is eliminated, and the elastic force of the leaf spring 58 causes the rotor 5 to rotate.
As a result, the rotation of the shaft 53 is stopped (FIG. 7A).

[0007]

In the above-described configuration, the fitting portion 50 of the field 51 and the shaft 53 are in contact with each other, so that the exciting coil portion 5 and the shaft 53 are in contact with each other.
At the time of energization to 2, the opposing surfaces are rubbed and a magnetic attraction force is generated by the magnetic flux M1 traversing these surfaces, so that a large load is applied to the rotation of the shaft 53. As a result, the rotation of the shaft becomes unstable,
The shaft vibrates in the direction of the contact surface to generate noise, or the wear of the rubbing surface is abnormally worn, thereby shortening the life of the clutch or causing the frictional heat to easily cause seizure. There was a problem of becoming. Here, there is a method using a ball bearing instead of the fitting portion 50 (for example, Japanese Utility Model Publication No. Hei 7-24666), but this leads to an increase in the size and cost of the clutch.

Further, in the clutch shown in FIG. 7, since it is necessary to energize the exciting coil section 52, a lead wire (lead wire) 65 covered with an insulating material passes from a magnetic generating section through a notch 66 in which a part of the field 51 is cut out. A terminal 67 that can be drawn out and connected to a terminal on the power supply side is attached to an end thereof.
Here, since the field 51 is made of a sheet metal such as an iron-based metal, the lead wire coating is rubbed in the notch when the clutch is assembled or mounted on a copying machine or the like, so that the coating is damaged and the field is damaged. There was a case of short circuit. When the lead wire is drawn out as a guard of the lead wire through a cylindrical protrusion integrally formed on the bobbin (made of resin) of the exciting coil portion 52, the lead wire is passed through the cylindrical protrusion. There was a problem that it became complicated.

The present invention has been made in view of the above circumstances, and has as its object to provide an electromagnetic clutch which is small, inexpensive, has excellent durability, and can simplify the assembly process.

[0010]

In order to achieve the above object, an object of the present invention is to provide a shaft rotatable around an axis and having at least a magnetic member, and an input-side rotator externally fitted to the shaft. And an output-side rotator, the excitation coil portion externally fitted to the shaft and having a projection on the surface thereof, and a field surrounding the excitation coil portion, wherein the field is formed on the surface of the excitation coil portion. It is characterized in that it has a notch that engages with the projection and that it is not in contact with the magnetic part of the shaft.

According to this structure, the shaft, which is the magnetic material constituting the magnetic flux path, is set so as not to contact the field, so that the magnetic materials do not come into direct sliding contact with each other at the time of excitation, and the rotation of the shaft is stabilized. As a result, generation of vibration and noise is suppressed, and as a result, excellent durability without abnormal wear and seizure is obtained. In addition, since the projection formed on the surface of the exciting coil portion and the cutout portion of the field are engaged, the exciting coil in contact with the shaft does not rotate when the shaft rotates.

According to a second aspect of the present invention, in the first aspect, a gap holding member made of a non-magnetic material is interposed between the field and the magnetic portion of the shaft. .

According to this structure, the shaft, which is a magnetic material constituting the magnetic flux path, and the field can be held more stably so as not to come into contact with each other, so that the magnetic materials do not directly come into sliding contact with each other during excitation, and the rotation of the shaft is reduced. As a result, the generation of vibration and noise is further suppressed, and as a result, superior durability without abnormal wear and seizure is obtained.

[0014] The invention of claim 3 is the invention of claims 1 and 2
Wherein the exciting coil section includes at least a bobbin for holding the coil, and a gap holding member interposed between the field and a magnetic body of the shaft is a part of the bobbin.

According to this structure, since the bobbin made of a non-magnetic material and placed in contact with the magnetic material of the field and the shaft is used as the gap holding member, there is no need to add any special components, and the device is small and inexpensive. An electromagnetic clutch can be provided.

Further, the invention of claim 4 provides the invention according to claims 1 to 3
Wherein the exciting coil portion has a flange portion to which a lead wire is connected, and a groove communicating from the flange portion to a tip end of a protrusion formed on the surface of the exciting coil portion. It is characterized by the fact that a lead wire is laid.

According to this configuration, since the projection serving as a detent for the exciting coil part also serves as a guard for the lead wire, there is no need to provide another detent. In addition, since the notch of the field which engages with the projection also serves as a lead-out port for the lead wire, there is no need to provide another lead-out port, and these can make the electromagnetic clutch more compact and less expensive.

According to a fifth aspect of the present invention, in the fourth aspect, the groove in which the lead wire of the protrusion is laid is provided.
A protrusion for locking the lead wire is provided along the line.

According to this configuration, since the lead wire can be fixed to the projection only by fitting it between the protrusions, the assembly is completed in a very short time. In addition, since no additional fixtures or parts are required, the skill of the assembling work is not required, resulting in low cost.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The electromagnetic clutch of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view (a) and a side view (b) of an electromagnetic clutch according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. In these figures, the electromagnetic clutch 10 has a through hole 112 at the bottom 111.
And a housing (field) 11 having a single-sided opening, which forms a bottomed double tubular body 117 together with an inner tubular portion 115 forming an opening 112 and an outer tubular portion 116. The bottom portion 111 is fixedly provided with a rotation preventing portion 113 protruding outward, and the housing 11 is formed by the rotation preventing portion 113 and the bottomed double cylindrical body 117.
Is composed. The housing 11 is made of a magnetic material such as an iron-based metal, and has a notch 114 formed on an opening side thereof for drawing out a lead wire 127 of the excitation coil portion 12 described later to the outside. In the housing 11, the detent part 113 and the bottomed double cylindrical body 117 are separately manufactured by subjecting a sheet metal material to pressing, drawing, or the like, and then the two are joined and fixed by caulking or the like. You.

The excitation coil portion 12 is housed in the double cylindrical body 117 with a bottom of the housing 11. The excitation coil section 12 includes three flanges 121, 122, 123
A coil is formed by winding a wire between the flanges 122 and 123 of the bobbin 124 having
An insulating sheet 126 is wound around the outer periphery of the coil 25, and the lead wires 127 at both ends of the coil 125 are sandwiched and fixed between the flanges 121 and 122. On the outside of the flange 121 of the bobbin 124, the projection 21 is provided integrally with the bobbin 124. And the projection 21
Are protrusions 2 provided on the bottom 111 of the housing 11.
1 is fitted into a notch 114 having substantially the same shape as the cross section of the projection 1, and the tip of the projection 21 is slightly projected from the bottom 111. The lead wire 127 is drawn out of the notch 114 of the housing 11 to the outside through a groove of the protrusion described later.

The cylindrical portion 22 (gap holding member) between the through hole 128 formed in the axial direction of the bobbin 124 and the concave portion 129 formed on the right surface (FIG. 1A) of the bobbin 124 is a resin bobbin 124. Is formed integrally with the bobbin with the same material as the above, and the outer diameter of the cylindrical portion 22 is
2 is substantially equal to the inner diameter of the inner cylindrical portion 115 forming
The inner diameter of 2 is substantially equal to the outer diameter of the outer fitting cylinder 15 of the shaft 13 described below. Then, the through hole 128
The right end side of the inner cylinder portion 115 of the housing 11 has a recess 129.
Is arranged and held coaxially with the through-hole 112.

The shaft 13 is rotatably inserted into a through hole 128 of the exciting coil section 12 housed in the housing 11. The shaft 13 includes a central shaft body 14 formed by resin molding, and an outer fitting cylindrical body 15 formed of a magnetic material such as an iron-based metal and externally fitted to the central shaft body 14.

The central shaft 14 has a through hole 141 through which an external shaft is inserted in the axial direction, a flange 142 formed at one end to be in contact with the outer surface of the bottom 111 of the housing 11, and an outer periphery at the other end. And a ring-shaped groove 143 into which the ring-shaped locking member 20 such as a washer is fitted. The center shaft body 14 has a D-shaped cross-section on the left end side of the through hole 141 in the drawing, and
The outer peripheral surface from the position where the flange 142 is formed to a position closer to the other end than the center is a regular decagonal cross section, and the part having the regular decagonal cross section is the outer fitting cylinder 15 and the rotor 16. Constitute a fitting portion 144 to which the outside is fitted.

The inner peripheral surface of the outer fitting cylinder 15 is the center shaft 1.
4 is formed so as to have a regular decagonal cross section that matches the cross sectional regular decagonal shape of the outer peripheral surface of the fitting portion 144 at a position where the other end of the central shaft body 14 contacts the flange 142 at one end. And is prevented from rotating by the fitting portion 144 of the central shaft body 14. The outer fitting cylinder 15 is set so that its length dimension is substantially equal to the sum of the thickness dimension of the bottom 111 of the housing 11 and the length dimension of the bobbin 124. The dimensions of the bobbin 12 are set to be substantially the same as the diameter of the through hole 128 of the bobbin 124, and include the outer peripheral surface of the outer fitting cylinder 15 and the inner peripheral surface of the cylindrical portion 22.
4 and the inner peripheral surface form a rubbing surface so that they can be rotatably held together.

On the other hand, the inner cylinder 115 of the housing 11
The outer diameter of the outer fitting cylinder 15 is slightly larger than the inner diameter of the outer fitting cylinder 15, and a slight gap is provided so as not to contact the outer peripheral surface of the outer fitting cylinder 15. Part 1
15 faces the inner peripheral surface at a slight distance, and the housing 1
A portion of the inner cylinder portion 115 inserted into the concave portion 129 of the bobbin 124 is configured to hold a gap between the inner cylinder portion 115 and the outer fitting cylinder 15 with the cylinder portion 22 of the bobbin 124 interposed therebetween.
The thickness of the interposed cylindrical portion 22 is substantially equal to the distance of the gap between the housing 11 and the outer fitting cylindrical body 15.
When it is larger than 1 mm, the magnetic resistance in the magnetic flux passage increases, which tends to hinder the clutch operation at the time of energization. When it is smaller than 0.05 mm, the outer periphery of the cylindrical body 15 and the through hole are reduced. In addition to the need for high surface accuracy on the inner circumference of the
2 becomes too thin to maintain strength, resulting in an increase in cost. More specifically, in the range of 0.1 mm to 0.5 mm, sufficient strength and performance can be obtained at low cost.

Various resin polymers, non-magnetic metals, non-magnetic ceramics, and the like can be used as the constituent material of the gap holding member interposed between the outer fitting cylinder 15 and the housing 11, and the material is impregnated with oil. And those containing solid oil. In this embodiment, which is formed integrally with the bobbin (the cylindrical portion 22)
In this case, the material may be selected from those using a resin as a base material. Further, in order to reduce the frictional resistance with the outer peripheral surface of the outer fitting cylinder 15, the inner peripheral surface of the cylindrical portion 22 that slides on the outer peripheral surface of the outer fitting cylinder 15 may be coated with a sliding material such as a fluororesin. Good.

On the opening side of the housing 11, a rotor 16 as an output side rotating body is fitted at a position facing the exciting coil section 12 of the shaft 13. The rotor 16 is made of a magnetic material such as an iron-based metal, and has a small diameter formed with a through hole 161 through which the shaft 13 is inserted at the center and a concave portion 162 formed on a surface opposite to the exciting coil 12. And a plurality (three in the present embodiment) of slits formed so as to be externally fitted into the annular body 163 by press-fitting and to surround the through hole 161 of the annular body 163 inside the outer peripheral edge. And a large-diameter annular body 166 in which a concave portion 165 is formed on the surface opposite to the exciting coil 12.
The inner peripheral surface of the through hole 161 of the small-diameter annular body 163 has a regular decagonal cross section substantially similar to the decagonal shape of the outer peripheral surface of the fitting portion 144 of the central shaft body 14. The hole 161 is externally fitted to the fitting portion 144 of the central shaft body 14 and is attached to the shaft 13 in a detented state.

The large-diameter annular body 16 of the rotor 16
The outer peripheral surface of the housing 6 is opposed to the surface of the cutting portion 118 formed on the inner peripheral front surface of the outer cylindrical portion 116 of the housing 11 with a slight gap. This is for the following reason.
Although it is necessary that the annular body 166 and the outer cylinder portion 116 of the housing 11 be close to each other so that a magnetic path is formed at the time of excitation, the annular body 166 rotates with respect to the housing 11. If they come into contact with each other, problems such as seizure occur. For this reason, it is necessary to provide a small gap such that the two do not contact each other. This magnetic path will be described later.
Specifically, the gap between the annular body 166 and the outer cylindrical portion 116 of the housing 11 can be set in the range of 0.05 mm to 1 mm. If the gap is larger than 1 mm, the magnetic resistance in the magnetic flux path increases, so Clutch operation is likely to be hindered, and if it is smaller than 0.05 mm, high surface precision of the outer peripheral surface of the annular body 166 and the surface of the housing 11 cutting portion 118 is required, which increases costs. More specifically, in the range of 0.1 mm to 0.5 mm, sufficient performance can be obtained at low cost.

A gear 17 which is an input-side rotating body is externally fitted to the shaft 13 at a position opposite to the exciting coil 12 with respect to the rotor 16 so as to be rotatable around the shaft 13. The gear 17 is formed by, for example, resin molding. A plurality of teeth 171 are formed at an equal pitch on an outer peripheral surface, and a cylindrical portion 172 through which the shaft 13 is inserted is formed at a radially central portion so as to protrude toward the rotor 16. The end of the cylindrical portion 172 on the rotor 16 side is arranged in a state of contact with the bottom surface of the concave portion 162 of the rotor 16.

A plurality of (three in this embodiment) position regulating portions 175 composed of a pair of position regulating protrusions 173 and 174 formed in the circumferential direction are provided on the outer periphery of the cylindrical portion 172.
They are formed at equal intervals in the circumferential direction so as to protrude from the seven surfaces. The position regulating projections 173 and 174 are set such that the thickness dimension in the axial direction of the shaft 13 is slightly larger than the plate thickness dimension of the armature 18 described later. Is set to a value slightly larger than a width dimension of a later-described convex portion 182 of the armature 18.

Further, on the outer periphery of the cylindrical portion 172, a retaining projection 176 is formed at a tip end thereof and corresponding to a position between the adjacent position regulating portions 175, which protrudes in the radial direction. In the present embodiment, since three sets of the position restricting portions 175 are formed, three retaining projections 176 are formed. The retaining projection 176 and the position regulating projections 173, 17
4 is set to a value substantially equal to a thickness dimension of the ring body 19 described later. Also,
The retaining projection 176 is an inclined surface that is separated from the rotor 16 as the surface on the rotor 16 side is separated radially outward from the peripheral surface of the cylindrical portion 172.

On the surface of the gear 17 on the rotor 16 side,
In the center, a through hole 181 having a diameter larger than the outer diameter of the cylindrical portion 172
An annular armature 18, which is a transmission body formed with, is arranged so that the through hole 181 is inserted into the cylindrical portion 172. The armature 18 is made of a magnetic material such as an iron-based metal, has an outer diameter set to a size substantially equal to the outer diameter of the rotor 16, and has a plurality of (three in this embodiment) at predetermined intervals around the periphery of the through hole 181. The projections 182 are formed so as to protrude inward in the radial direction. Each projection 182 is held by the gear 17 in a state where it is fitted between the pair of position regulating projections 173 and 174 and is prevented from rotating. 17 and rotates together.

A ring body 19 formed of an elastic polymer material such as synthetic resin such as polyester or rubber, or an elastic metal material such as stainless steel is fitted on the cylindrical portion 172. The ring body 19 is set so that the inner diameter is slightly larger than the outer diameter of the cylindrical portion 172 and the outer diameter is smaller than the through hole 181 of the armature 18, and the position regulating protrusions 173 and 174 and the retaining protrusion 176. And is arranged so as to be fitted outside. Then, even if the armature 18 moves in a direction away from the gear 17,
The armature 18 is prevented from coming off the gear 17 by contacting with the ring body 19. In addition, for example, after the ring body 19 is placed on the radially inclined surface of each of the retaining protrusions 176, a pressing force is applied to the gear 17 side to be stretched in the radial direction along the inclined surface of the retaining projections 176, and By moving over the protrusion 176, the cylindrical portion 172 is formed.
Is fitted to the outside.

The ring-shaped groove 1 at the other end of the central shaft 14
A ring-shaped locking member 20 such as a washer, which is a locking means, is fitted into 43. As a result, the central shaft 1 is formed by the flange 142 of the central shaft 14 and the ring-shaped locking member 20.
Positioning of each component on 4 is performed.

FIG. 3 shows the bobbin 124 of the exciting coil 12.
FIG. 5 is an enlarged perspective view of a protrusion 21 provided in the projection 21. The protrusion 2
The reference numeral 1 denotes a bobbin 124 which stands on a side surface near the peripheral surface of the flange 121 in a vertical direction (a direction parallel to the axis of the bobbin) from the side surface, and is integrally molded with the bobbin 124 by resin.
The protrusion has a substantially rectangular cross-sectional shape in which one side on the outer peripheral side of the flange 121 has an arc shape, and has a protrusion length slightly larger than the sheet metal thickness of the bottom portion 111 of the housing 11. Protrusion 21
A slit-shaped groove 211 is opened from the flange 121 to the tip of the protrusion at the center of the arc side of the groove 21.
Reference numeral 1 denotes a deep section in the center direction of the bobbin axis, which has a cross-sectional shape that expands in a T-shape in the longitudinal direction of the cross section of the projection 21. In other words, the sheath 212 has a shape in which the slit 212 communicating with the inside of the sheath extends along the length of the sheath. A total of four protrusions 213 are formed in the groove 211 inside the protrusion 21 so as to protrude from the top of the right and left heads of the T-shape so as to be opposed from the top and bottom, along the groove 211. In other words, this projection 2
Due to the inner protrusion of the groove 1, the left and right sides of the cross-section T-shaped head of the groove 211 have a narrowed bifurcated root.

The lead wires 127 at both ends of the coil 125 sandwiched and fixed between the flanges 121 and 122 are covered with a vinyl tube or the like and housed in a groove 211 opened from the flange 121 to the protrusion 21. It is pulled out from the tip. FIG. 3 shows a stored state of one of the two covered lead wires. Slit 2
The lead wires inserted into the groove 211 along the line 12 are distributed to each of the left and right branched grooves, and are stored and provided one by one in the storage portion 214 that is half-partitioned by the protrusion 213.
Here, the width of the T-shaped portion of the slit 212 and the groove is larger than the coating diameter of the lead wire 217, and the width of the portion narrowed by the protrusion 213 is set smaller than the coating diameter. It is housed and does not come off because it is locked by the protrusion 213.

The electromagnetic clutch 10 constructed as described above
Is a central shaft 1 in which an external shaft such as a paper feed mechanism in an image forming apparatus such as a copying machine forms a shaft 13.
4 is inserted into the through hole 141, and the rotation preventing portion 113 attached to the housing 11 is fixed to a fixing member inside a device such as an image forming apparatus, and is attached so that the housing 11 does not rotate. In this state, when a rotational force is applied to the gear 17 from an external drive source, the gear 17 rotates around the shaft 13 together with the armature 18.

In this state, when the excitation coil section 12 is energized, the housing 11, the outer fitting cylinder 15 and the rotor 1
The magnetic flux generated by the exciting coil unit 12 is generated in the magnetic path formed by the magnetic field 6. However, since the magnetic resistance of the rotor 16 increases due to the presence of the through hole 164, the magnetic flux is generated by the armature located near the rotor 16. 18 will be generated. Therefore, a magnetic attraction force for attracting the armature 18 to the rotor 16 is generated, and as shown in FIG. 4, the armature 18 moves toward the rotor 16 against the elastic force of the ring body 19 and is attracted to the rotor 16. Will be. In addition, the code | symbol M in FIG. 4 has shown the magnetic flux produced | generated via the armature 18. FIG.

That is, the armature 18 is
Is pulled toward the rotor 16 by the magnetic attraction force, the pressing force is applied by the convex portions 182 of the armature 18 to the portion of the ring member 19 corresponding to the area between the adjacent retaining projections 176. As a result, the armature 18 is attracted to the rotor 16 against the elastic force of the ring body 19. Therefore, as a result of the rotation of the rotor 16 together with the armature 18, the rotational force of the gear 17 is transmitted to the shaft 13, and the shaft 13 rotates according to the rotation of the gear 17.

On the other hand, when the energization to the exciting coil section 12 is cut off, the magnetic attraction force on the rotor 16 disappears because the magnetic flux M disappears.
The pressing force applied to 9 is released. For this reason, the armature 18 is returned to the original position separated from the rotor 16 by the return force of the ring body 19 that has been deformed and deformed to return to the original state without bending, and the rotational force of the gear 17 to the shaft 13 is reduced. The transmission is interrupted, and the rotation of the shaft 13 is stopped.

Next, the state of opposition between the housing 11 and the external fitting cylinder 15 and the density of the magnetic flux M when the excitation coil portion 12 is energized will be described with reference to FIG. As described above, the magnetic flux M is generated by the excitation through the armature 18 located in the vicinity of the rotor 16, and the armature 18 is drawn toward the rotor 16. As a result, the driving force of the gear 17 is reduced through the armature 18 to the rotor 16 and the rotor 16. The power is transmitted to the shaft 13 stopped by the rotor 16. Here, the greater the magnetic flux M, the greater the density of the rotor 1
As a result, the magnetic attraction between the armature 6 and the armature 18 is increased, so that the slip is less likely to occur and the transmitted driving force is increased.

However, as described above, there is a small gap between the housing 11 and the outer fitting cylinder 15, and the magnetic flux M crossing the gap has a small magnetic area when the opposing areas of the two are small. The density of the generated magnetic flux M decreases, and the driving force is not sufficiently transmitted. For example, in the electromagnetic clutch according to the present embodiment, the facing width a in the axial direction which affects the facing area.
(A confronting portion between the housing 11 and the outer fitting cylinder 15)
It suffices if it is 1.2 mm or more, preferably 2 mm or more.

The electromagnetic clutch 10 according to the embodiment of the present invention
As described above, the outer fitting cylinder 15 of the shaft 13 rotates in contact with the bobbin 124 to rotate the housing 11 and the outer fitting cylinder 15.
Between the magnetic material and the magnetic material constituting the magnetic flux path (the externally fitted cylindrical body 15 of the shaft and the housing 11) do not come into direct sliding contact with each other at the time of excitation, and the rotation of the shaft 11 is stabilized. As a result, generation of vibration and noise is suppressed, and as a result, excellent durability without abnormal wear and seizure is obtained. Further, since the projection 21 of the exciting coil portion 12 is engaged with the cutout portion 114 of the housing 11, the exciting coil portion 12 that comes into contact with the shaft 13 does not rotate when the shaft 13 rotates.

Further, since the cylindrical portion 22 of the bobbin 124 is interposed between the housing 11 and the outer fitting cylindrical member 15 like a so-called spacer, the gap is stably held, so that the magnetic flux is reduced. Magnetic material composing the passage (shaft 13
The outer fitting cylinder 15 and the housing 11) do not directly contact with each other at the time of excitation, and the state is stabilized. Therefore, the rotation of the shaft 13 is further stabilized, and the generation of vibration and noise is further suppressed, and as a result, superior durability without abnormal wear or seizure is obtained.

Further, since the cylindrical portion 22 is formed integrally with the bobbin 124 of the exciting coil portion 12, there is no need to increase the number of parts, and a small and inexpensive electromagnetic clutch can be provided.

Further, a groove 211 is formed in the projection 21 of the exciting coil section 12 in which the lead wires 127 at both ends of the exciting coil are disposed, and the lead wire is drawn out of the housing 11 through the groove. Leader 1 in notch 114
The cover 27 is not directly rubbed, so that the cover is not damaged at the time of assembling the clutch or assembling to a copying machine or the like, and the housing 11 does not leak. In addition, since the projection 21 also serves as a detent and a guard for the lead wire 127, there is no need to provide another detent, and the notch 114 of the housing that engages with the projection 21 makes the outlet of the lead wire 127 an outlet. Since they are also used, there is no need to provide additional outlets, and these can further reduce the size and cost of the electromagnetic clutch.

Furthermore, since the protrusion 213 that supports the lead line so as not to be displaced is provided along the groove 211 in which the lead line 127 of the protrusion is provided, the lead line is formed by the protrusion 21.
3 and 213, it can be fixed to the projections, and the assembly is completed in a very short time. Also, since no additional fixtures or parts are required, skill in assembly work is not required, and as a result, cost reduction is facilitated.

It should be noted that the electromagnetic clutch of the present invention is not limited to the above-described embodiment, but may adopt various modifications as described below.

(1) In the above embodiment, the exciting coil unit 1
Although the second lead wire 127 is taken out on the bottom 111 side of the housing 11 (in the axial direction of the electromagnetic clutch 10), it can be taken out on the outer peripheral surface of the housing as needed. In FIG. 5, the approaching flange 32 for pinching and fixing the lead wire to the rotor 316 side of the bobbin 324 is shown.
2, 323 are provided, and a projection 321 is integrally formed on the flange 322 side on the outer periphery of the flange 323. In this case, the flange 323 is formed separately from the bobbin 324, and after the coil is wound around the bobbin, the flange 323 is connected to the bobbin 32.
4, it may be assembled simultaneously with the work of holding and fixing the lead wire. Also, the projection 3 of the outer peripheral cylinder of the housing 311
A notch 314 having a width slightly larger than the protrusion 321 is provided from the projecting position 21 to the right end (gear side) of the outer peripheral cylinder. When the exciting coil portion is assembled to the housing, the exciting coil portion with the protrusion 321 can be inserted from the right side of the housing. It has become. The protrusion 321 is provided with a groove and a protrusion for providing a lead wire as in FIG. Also in this embodiment, protection of the rotation preventing lead wire of the exciting coil portion and simplification of taking out the lead wire are sufficiently possible.

(2) In the above embodiment, the housing 11
The gap holding member for holding the gap between the outer fitting cylindrical body 15 and the shaft is formed in a ring shape like the cylindrical portion 22. However, it is not necessary to separately provide one circumference of the ring, and it is divided into two or more along the circumference. There may be a notch to divide into. Further, the inner or outer circumference of the ring does not need to be a perfect cylindrical surface, and may be a shape in which concave portions are periodically present.
The point is that the difference in distance from the center of the shaft between the outermost part of the gap holding member from the center of the shaft and the innermost closest part matches the desired distance between the housing and the shaft external fitting cylinder. I just need. Further, although the cylindrical portion 22 is formed integrally with the bobbin 124, the cylindrical portion 22 may be independent as a separate ring. In this case, it is possible to use a different material from the bobbin.

(3) In the above embodiment, the projection 21 of the bobbin 124 has a substantially rectangular cross-sectional shape, but is not limited to this shape. Any shape, such as a circle, an ellipse, and a polygon, can be used as long as it can form a detent. Further, the tip of the projection may be tapered slightly so that the projection can be easily inserted into the notch 127 of the housing 11 when the exciting coil portion 12 is inserted into the housing 11. In the embodiment shown in FIG. 5, a groove in the axial direction of the bobbin is provided in a protruding portion facing the outer peripheral cylindrical portion of the housing, and when the exciting coil portion is inserted into the housing, the edge of the cutout of the housing sandwiches the groove. The insertion direction may be guided.

(4) In the above embodiment, the groove 21 for attaching the lead wire 127 provided on the projection 21 of the bobbin 124 is provided.
1 has a T-shaped cross section, but is not limited to this shape.
For example, the groove may be L-shaped as shown in FIG. 6A, or the groove may be made independent for each lead line as shown in FIGS. Also, although the wire storage portions 214 are separated from each other,
(A) It does not have to be separated as in (b). The protrusions 213 for locking the lead wire are provided at a total of four places at the entrance of the groove, but if the storage parts are not separated as in (a) and (b), only two positions are possible. (E)
It is also possible to reduce the number by providing a high protrusion on only one side as shown in FIG. The point is that all the lead lines are stored in the back of the slit 212, and a locking portion having a smaller gap than the lead wire covering may be provided somewhere between the slit and the storage portion.

(5) In the above embodiment, the exciting coil unit 1
Notch 114 on housing 11 side receiving second projection 21
Communicates with the through hole 112, but the housing 11
May be communicated from the outer periphery side, and even if the communication is not performed, the effect of the present invention is not reduced. When the notch is inserted into the housing after the terminal is attached to the end of the lead wire, the notch may be simply set to a size through which the terminal passes.

[0055]

As described above, according to the first aspect of the present invention, since the field forming the magnetic flux path and the magnetic portion of the shaft are not in contact with each other, there is no direct sliding contact when the exciting coil is excited. And the generation of vibration and noise is suppressed, and as a result, excellent durability without abnormal wear and seizure is obtained. In addition, since the field has a notch that engages with a projection formed on the surface of the exciting coil portion, the exciting coil portion that comes into contact with the shaft does not rotate when the shaft rotates.

According to the second aspect of the present invention, since the gap between the field and the shaft is stably maintained, the rotation of the shaft is further stabilized, and the generation of vibration and noise is further suppressed. Superior durability without excessive wear and seizure is obtained.

According to the third aspect of the present invention, since the non-magnetic material for holding the gap is formed integrally with the bobbin of the exciting coil portion, there is no need to increase the number of special components, and the electromagnetic clutch is small and inexpensive. Can be provided.

According to the fifth aspect of the present invention, the bobbin has a flange portion to which a lead wire is connected, and a groove communicating from the flange portion to a tip end of a projection formed on the surface of the bobbin. Since the lead wire is laid in this groove, the projection serving as a detent for the exciting coil part also serves as a guard for the lead wire, and there is no need to provide another detent. In addition, the notch of the field which engages with the projection also serves as the lead-out opening of the lead wire, so that there is no need to provide another lead-out opening, and these can make the electromagnetic clutch more compact and less expensive.

According to the sixth aspect of the present invention, the protrusion in which the lead line of the protrusion is laid is provided along the protrusion for supporting the lead line so as not to come off. The assembly can be completed in a very short time because it can be fixed to the projection only by fitting. In addition, since no additional fixtures or parts are required, the skill of the assembling work is not required, resulting in low cost.

[Brief description of the drawings]

FIG. 1A is a sectional view of an electromagnetic clutch according to an embodiment of the present invention, and FIG.

FIG. 2 is an exploded perspective view of the electromagnetic clutch shown in FIG.

FIG. 3 is an enlarged perspective view of a projection provided on an exciting coil unit applied to the electromagnetic clutch shown in FIG.

FIG. 4 is a cross-sectional view for explaining the operation of the electromagnetic clutch shown in FIG.

FIG. 5 shows an electromagnetic clutch A according to another embodiment of the present invention.
-A sectional view (a) and side view (b).

FIG. 6 is a partially enlarged view of a main part of an electromagnetic clutch according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a configuration of a conventional electromagnetic clutch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electromagnetic clutch 11 Housing (field) 12 Exciting coil part 13 Shaft 15 Externally fitted cylindrical body (magnetic body part) 16 Rotor (output side rotating body) 17 Gear (input side rotating body) 21 Projection 22 Tube part (gap holding member) 114 Notch 121, 122, 123 Flange 124 Bobbin 127 Leader 211 Groove 213 Projection

Claims (5)

[Claims] 1. A shaft rotatable around an axis and having at least a magnetic body, an input-side rotator and an output-side rotator externally fitted to the shaft, and a projection mounted on the shaft and externally fitted to the shaft. And a field surrounding the excitation coil part, the field having a notch that engages with a projection formed on the surface of the excitation coil part, and a magnetic body part of the shaft. Is a non-contact electromagnetic clutch. 2. The electromagnetic clutch according to claim 1, wherein a gap holding member made of a non-magnetic material is interposed between the field and the magnetic portion of the shaft. 3. The device according to claim 2, wherein the exciting coil portion includes at least a bobbin for holding a coil, and a gap holding member interposed between the field and a magnetic body of a shaft is a part of the bobbin. Item 3. The electromagnetic clutch according to Item 1 or 2. 4. The exciting coil section has a flange section to which a lead wire is connected, and a groove communicating from the flange section to a tip end of a projection formed on the surface of the exciting coil section. The electromagnetic clutch according to any one of claims 1 to 4, wherein a lead wire is laid. 5. The groove in which the lead wire of the projection is laid,
The electromagnetic clutch according to claim 5, wherein a protrusion for locking the lead wire is provided along the line.