JPH03324A - Small electromagnetic clutch mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is used as an intermittent power transmission mechanism for mechanical parts of small printing devices installed in electronic office equipment such as calculators, cash registers, and typewriters. This article relates to a small electromagnetic clutch mechanism that is often used.

[Prior art] In recent years, electromagnetic clutch mechanisms used for these applications are
For the purpose of ensuring reliability, reducing power consumption during operation, and simplifying the mechanism, a small electromagnetic clutch mechanism using a cup-shaped yoke is preferably used. This is achieved by keeping the suction plate in constant contact with the constantly rotating yoke while the printing device is in operation, and by energizing the electromagnetic coil, a suction force is generated between the yoke and the suction plate, which reduces the frictional force on the contact surface. This is a type of power transmission system.

A conventional electromagnetic clutch mechanism of this type uses a yoke having a shape as shown in FIG. 8, and in order to obtain the shape of the yoke, a round bar material is used and lathed. Incidentally, the manufacturing cost of the yoke component accounts for more than half of the component cost of this type of electromagnetic clutch mechanism.

[Problem to be solved by the invention] However, in the above-mentioned conventional technology, the time required for parts processing,
In other words, the cycle time is very long (approximately 1°5 minutes), and in order to ensure the accuracy of the air gap δ in the 8th country, it is difficult to manage tools when machining the yoke. The cost was high. Furthermore, when operating a device that incorporates this small electromagnetic clutch, it attracts the clutch and rotates as a unit only when switching operations is required.
Normally, the yoke and the suction plate are in sliding contact with each other, which has the drawback of being easily worn out and reducing reliability. In many cases, efforts are made to reduce wear by applying high-hardness plating to the yoke and suction plate and using lubricating oil, but due to the required characteristics of the lubricating oil, if the viscosity is increased, the suction plate will rotate around and malfunction. This necessitated the use of low-viscosity lubricating oil, which resulted in the problem of poor oil retention due to scattering.

The present invention has been made in view of these drawbacks, and its purpose is to provide a compact electromagnetic clutch that is much lower in cost. Another purpose is to prevent deterioration in reliability due to wear and ensure durability over time.

[Means for Solving the Problems] Firstly, in order to provide a low-cost small electromagnetic clutch, the present invention uses deep drawing processing instead of cutting processing for the yoke processing, and also reduces the air gap d after assembling the electromagnetic clutch. A jig is used to ensure accuracy when joining the yoke and cylindrical member,
Furthermore, a flange portion is integrally provided on the outer periphery of the yoke.

In addition, in order to ensure durability and reliability, the yoke or suction plate is characterized by having minute pitch grooves carved by coining on the contact surface between the yoke and the suction plate.

[Function] According to the above configuration of the present invention, the yoke can be machined by deep drawing instead of cutting to produce a component shape in a short cycle time, and the air gap d after assembling the electromagnetic clutch can be reduced. Tool management is simplified because ensuring accuracy does not depend on accuracy control during lathe machining, and the flange provided on the outer periphery of the yoke significantly increases the sliding and suction area with the suction plate, reducing contact surface pressure. , the surface treatment of the yoke and suction plate can be greatly simplified. In addition, on the contact surface between the yoke and the suction plate, grooves with a minute pitch are carved in the yoke or the suction plate by coining processing, and these grooves greatly improve the oil retention effect, thereby preventing a decrease in reliability due to wear. I can do it.

[Embodiment] FIG. 1 is a perspective view showing the configuration of a small electromagnetic clutch in an embodiment of the present invention, and FIG. 2 is a sectional view of the same content. In FIG. 1, reference numeral 5 denotes a drive body which is rotated by power, and the yoke 1 is fixed to this by being crimped after the pin 5-a passes through the hole 1-a. As shown in the figure, the yoke l has a thin cup shape with a flange portion 1-b formed on the outer periphery, and a single flange surface 1-c is in contact with the suction plate 4 (the manufacturing process of the yoke 1 will be described later). .

A cylindrical member (so-called iron core) coaxially arranged inside the yoke 1 is joined at one end as shown in FIG.

The yoke 1 and the cylindrical member 2 may be joined by any method such as press-fitting, adhesion, or sealing. During this joining, use a jig to
Define the gap δ shown in the figure. The gap δ is a step between the flange end face of the yoke 1 and the end face of the cylindrical member 2, and means an air gap between the suction plate 4 and the cylindrical member 2. An electromagnetic coil 3 is loosely fitted around the outer periphery of the cylindrical member 2 and is disposed within a space formed by the yoke 1 and the suction plate 4. As shown in FIG. 4, the suction plate 4 has a starfish shape and is configured to maintain stable contact with the flange end face 1-c of the yoke by being supported at three points. Moreover, this suction plate shape also has the meaning that the power line 3-a of the electromagnetic coil 3 can be drawn out. The suction plate 4 has a first
As shown in the figure, several holes 4-a are formed and fit into the pins 6-a formed in the driven body 6. Therefore, the suction plate 4 is restricted in the rotational direction with respect to the driven body 6, but is movable in the thrust direction. Between the suction plate 4 and the driven body 6,
As shown in Figure 2, a gap is provided in the assembled state, and the compression spring 8
The suction plate 4 energized by the yoke is always in contact with the flange end face of the yoke. By the way, a plurality of grooves are formed in the flange end face 1-C of the yoke, as shown in an enlarged view in FIG. In the case of this embodiment, the depth of this groove portion is set to about 0.1 degrees, and the pitch between each groove is set to about 0.2 degrees. Note that this groove may be composed of a plurality of concentric grooves or a single spiral groove, but either of these grooves is possible.

These grooves are formed between the yoke flange end face 1-C and the suction plate 4.
It is provided to store lubricating oil (not shown) that is applied to the contact and sliding surfaces of the bearing. The driven body 6 has a boss portion 6-b formed at the other end to which the driven shaft 7 is fixed. Further, restoring torque is applied to the driven shaft 7 by a torsion coil spring (not shown) in order to change the angle to the illustrated phase.

Here, a method for manufacturing the yoke 1 will be described. As mentioned above, since the conventional yoke shape was an integral shape as shown in FIG. 8, the only option was to machine the yoke from a round bar material by lathe processing. However, in this embodiment, the yoke 1 has a cup shape with a thin wall (approximately 0.4 mm), and can be formed by simple deep drawing and pressing as shown in FIG. 7th
The figure is a process diagram showing the forming process of this yoke 1.
The parts are machined in the process order of (a) → (b) → (C1 → (d) in the figure. Also, in the process ('b) in Figure 7, the above-mentioned Yoke flange end face 1-
A coining pattern is carved in c to form a minute groove, and the pattern of the mold is transferred by a press, forming the groove as shown in FIG. Since these steps are performed by a progressive press machine, the processing cycle time per part is short, and in the case of this embodiment, it takes about 1 second.

Furthermore, since the processing method is different from the conventional one, the cylindrical member that was at the center of the yoke 1 is inevitably made into a separate piece. However, unlike the yoke 1, this cylindrical member 2 has no mating member with which it contacts or slides, so it can function satisfactorily with only simple and low-cost rust prevention treatment. In addition,
The accuracy required for the cylindrical member 2 is the air gap δ shown in FIG. 3, but since this accuracy is ensured using a jig when joining with the yoke 1, there is little control over the accuracy of the individual parts. Therefore, the cylindrical member 2 can be simply cut from a round bar material and subjected to simple anti-rust treatment (such as application of anti-rust oil), and the processing cycle time in this embodiment is only about 5 seconds. Although the cylindrical member 2 is used in this embodiment, it would not depart from the gist of the present invention even if the cylindrical member 2 had a pipe shape.

Next, the operation of the mechanism configured as above will be explained.

In FIG. 2, the driver 5 is driven in the α direction,
It rotates at a speed of about 1100 Orp.

Further, the yoke 1 fixed thereto and the cylindrical member 2 joined to the yoke 1 are also rotating at the same speed. The electromagnetic coil 3 within the yoke is stationary without being affected by the rotation of the yoke 1, and the power line 3-a is connected to an energization control section (not shown). When the electromagnetic coil 3 is not energized, no electromagnetic action occurs between the yoke 1, the cylindrical member 2, and the suction plate 4, and the suction plate 4 is not attracted to the yoke 1. Although a frictional torque due to the weak biasing force of the compression spring 8 is constantly acting on the contact surface between the yoke 1 and the suction plate 4, a restoring torque larger than this frictional torque is applied to the driven shaft 7. In this state, the suction plate 4 does not rotate with the yoke 1. By the way, in this actual flow meeting, the biasing force of the compression spring 8 is 5 gf, and this biasing force causes the yoke's flange single surface 1-c and the suction plate 4 to
The frictional torque generated at the contact surface is approximately 1 gf-Cm
-The restoring torque applied to the force driven shaft 7 is 5g.
f-cm or more.

When the electromagnetic coil 3 is energized, magnetic lines of force 9 are generated in the magnetic circuit composed of the yoke 1, the attraction plate 4, and the cylindrical member 2, as shown in FIG. It is attracted in the direction shown by . As a result, frictional force is generated at the contact portion A between the yoke 1 and the suction plate 4 due to attraction. Drive torque from the yoke l is transmitted to the suction plate 4 by this frictional force, and the driven body 6 and driven shaft 7 rotate.

Specifically, this embodiment assumes operation as an intermittent transmission clutch employed in a small printing device, and the angle at which the driven shaft 7 rotates by one energization to the electromagnetic coil 3 is at most 30 degrees. degree.

That is, by applying current to the electromagnetic coil, the suction plate 4 moves to the yoke l.
After the driven shaft 7 is driven by a predetermined angle by the power from the driver 5, the power line 3 of the electromagnetic coil returns to the original phase by the restoring torque of the torsion coil spring mentioned above.
-a will not become entangled with the suction plate 4 or the driven body 6.

Furthermore, this mechanism must ensure a durable torque transmission ability as a clutch under usage conditions that require intermittent operation several million times. Therefore, changes in the coefficient of friction between the yoke 1 and the suction plate 4 due to durable wear are not allowed. The groove carved into the yoke's flange end surface 1-c described above retains lubricating oil to prevent abnormal durability wear due to lack of oil, and on the other hand, improves the oil film's removal on contact surfaces that slide at high speed. It also has the effect of preventing contact separation due to the oil film of lubricating oil (so-called hydroplaning phenomenon). Furthermore, as shown in Fig. 6, since the yoke 1 and the suction plate 4 contact each other at the flange end face, the contact area is significantly increased compared to the conventional yoke end face shown in Fig. 8. surface pressure is decreasing. Therefore, for the surface treatment applied to the yoke 1 and the suction plate 4, it is possible to use low-cost materials with lower wear resistance.

[Effects of the Invention] As described above, according to the present invention, it is possible to produce a part shape in a short cycle time by using deep drawing processing instead of cutting processing for yoke processing, and it is possible to produce a part shape in a short cycle time. Tool management is simplified because ensuring the accuracy of the air gap d does not depend on accuracy control during lathe machining. Furthermore, the flange portion provided on the outer periphery of the yoke significantly increases the sliding/adsorption area with the suction plate and reduces the contact surface pressure, so the surface treatment of the yoke and suction plate can be greatly simplified. In addition, on the contact surface between the yoke and the suction plate, grooves with a minute pitch are carved into the yoke or the suction plate by coining, which greatly improves the oil retention effect and prevents reliability from decreasing due to wear. .

Therefore, it is a very effective technique for providing a small electromagnetic clutch with guaranteed durability and reliability at an extremely low cost, and has great technical and industrial significance.

FIG. 5 is a detailed sectional view of the flange end face of the yoke, FIG. 6 is a diagram showing the lines of magnetic force when the electromagnetic coil is energized, FIG. 7 is a diagram showing the machining process of the yoke, and FIG. FIG. 2 is a diagram illustrating a prior art.

yoke cylindrical member electromagnetic coil suction board

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of a small electromagnetic clutch mechanism according to the present invention, FIG. 2 is a cross-sectional view of the same content as FIG. 1, and FIG. 3 is a yoke, a suction plate, and a cylindrical member. A cross-sectional view showing a magnetic circuit portion consisting of

Claims (1)

[Claims] 1) Consisting of a cup-shaped yoke, a suction plate in contact with the opening side of the yoke, and an electromagnetic coil placed in a space formed by the yoke and the suction plate, In an electromagnetic clutch mechanism that transmits power by generating an attractive force between the yoke and the suction plate by energizing a coil,
A small electromagnetic clutch mechanism characterized in that the yoke is formed from a plate-shaped electromagnetic material by deep drawing and has a flange on its outer periphery. 2) In the clutch mechanism, a cylindrical member made of an electromagnetic material is provided on the inner periphery of the yoke, one end of which is joined to the yoke, and the other end of the cylindrical member is slightly larger than the flange end surface of the yoke. 2. The compact electromagnetic clutch mechanism according to claim 1, wherein the small electromagnetic clutch mechanism is recessed. 3) In the clutch mechanism, a groove with a minute pitch is carved by coining on the end face of the flange portion of the yoke or the end face of the suction plate according to claim 1.
The small electromagnetic clutch mechanism described.