JPH045775Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electromagnetic clutch used as a power switching means in printers and the like.

[Prior Art] An electromagnetic clutch is used as a mechanism for controlling the output of power input to a clutch gear to an electromagnetic plate.

The configuration of the electromagnetic clutch will be explained below based on the drawings. FIG. 1 is an exploded perspective view showing the structure of a general electromagnetic clutch. As shown in the figure, a plate spring 2 and an electromagnetic plate 3 are loosely fitted onto a rotating shaft 1a connected to a clutch gear 1, and an electromagnetic yoke 5 is further press-fitted therein. The electromagnetic yoke 5 is open downward and has a substantially cup-shaped shape with a convex portion 5a formed in the center, and the rotating shaft 1a is press-fitted into a through hole formed in the central convex portion 5a. There is. The electromagnetic coil 4 is inserted into the hollow part of the electromagnetic yoke 5, and the lower end surface 5b is connected to the electromagnetic plate 3.
It faces the top surface of. Further, the plate spring 2 serves to press the electromagnetic plate 3 against the electromagnetic yoke 5 side. Therefore, when a motor (not shown) rotates, the rotational force of the motor is input to the clutch gear 1 through a transmission mechanism consisting of gears, etc., and the electromagnetic yoke 5 rotates together with the clutch gear 1, but the electromagnetic plate 3 only receives frictional force. Does not have large rotational force. However, when the electromagnetic coil 4 is energized, the electromagnetic yoke 5 is magnetized and attracts the electromagnetic plate 3. Therefore, the rotational force of the electromagnetic yoke 5 is transmitted to the electromagnetic plate 3, and the electromagnetic plate 3 rotates.

As described above, in the electromagnetic clutch, the output of the power input to the clutch gear 1 to the electromagnetic plate 3 is controlled by controlling the energization to the electromagnetic coil 4.

However, the above-described electromagnetic clutch has the disadvantage that the lower end surface of the electromagnetic yoke 5 is worn out due to repeated adsorption with the electromagnetic plate 3, and the adhesion strength is reduced due to the abrasion powder.

In order to solve these drawbacks, electromagnetic yoke 5
Oil is applied to the lower end surface of the product to prevent wear due to repeated adsorption, but when such a configuration is used at low temperatures, the viscosity of the oil increases and the adsorption power decreases. There are drawbacks.

Further, during use, a phenomenon of adhesion occurs between the yoke and the plate, and there may be a delay in separating the yoke and the plate even after the electromagnetic coil is de-energized. To solve this problem, some devices have grooves provided on the opposing surfaces of the yoke and plate. (Jitsukai 1977
-86132 publication or Utility Model Application Publication No. 57-124629. ) [Problems that the inventions aim to solve] However, since the cut grooves provided in these inventions are all formed radially, it is difficult to process the grooves, resulting in high processing costs. The drawback was that it became a thing.

[Means for Solving the Problems] In order to solve the above drawbacks, the present invention includes a clutch gear, an electromagnetic yoke that rotates integrally with the clutch gear, an electromagnetic plate, and a pressing member that presses the electromagnetic plate against the electromagnetic yoke. The electromagnetic clutch is characterized in that the attracting surface of the electromagnetic yoke with the electromagnetic plate is ring-shaped, and a ring-shaped groove is formed in the attracting surface along the shape.

[Effect] The above means works as follows.

The abrasion powder and oil generated on the adsorption surface of the electromagnetic yoke 5 and the electromagnetic plate 3 are taken into the groove, and the abrasion powder and excess oil are always kept away from the adsorption surface, and by forming the ring-shaped groove, Grooves can be easily processed using a lathe or the like.

[Embodiment] FIG. 2 shows an embodiment of the electromagnetic yoke used in the electromagnetic clutch of the present invention. As shown in the figure, a ring-shaped groove 5c that follows the shape of the attraction surface 5b of the electromagnetic yoke 5 with respect to the electromagnetic plate 3 is machined using a lathe. An electromagnetic clutch is constructed using such an electromagnetic yoke 5. With this configuration, the electromagnetic yoke 5 and the electromagnetic plate 3
Abrasion powder and excess oil generated by repeated adsorption are captured into the grooves, and the adsorption surface is always kept coated with only the appropriate amount of oil.

[Effects] As described above, in this invention, the shape of the attraction surface of the electromagnetic yoke with the electromagnetic plate is ring-shaped, and by forming a ring-shaped groove along the shape of this attraction surface, Since the suction surface can be maintained in good condition, the suction strength does not decrease even when used for long periods of time or at low temperatures, and stable output can be controlled. etc., and as a result, an inexpensive electromagnetic clutch can be provided.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the structure of an electromagnetic clutch, and FIG. 2 is a perspective view of an electromagnetic yoke used in the present invention. 1...Clutch gear, 2...Plate spring, 3
...Electromagnetic plate, 4...Electromagnetic coil, 5...Electromagnetic yoke, 5c...Groove.

Claims (1)

[Scope of utility model registration request] In an electromagnetic clutch consisting of a clutch gear, an electromagnetic yoke that rotates integrally with the clutch gear, an electromagnetic plate, and a pressing member that presses the electromagnetic plate against the electromagnetic yoke, the shape of the attraction surface of the electromagnetic yoke to the electromagnetic plate is An electromagnetic clutch characterized in that it is ring-shaped and has a ring-shaped groove formed on the attracting surface along the shape.