JPS6145087B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an electromagnetic clutch/brake device, and a clutch friction plate or a brake friction plate in an electromagnetic clutch/brake device used in a motor with an electromagnetic clutch/brake. A flexible cork with internal pores and an appropriately regulated surface roughness is impregnated with a specific oil, and the same type of oil as this impregnated oil is used as a solid lubricant with an appropriately regulated particle size. The clutch plate or brake plate is made of cork material whose surface is coated with grease mixed with an anti-corrosion agent, and the metal material of the clutch plate or brake plate is carbon steel, and the electromagnetic plate has an appropriately selected roughness of the friction surface. This relates to a clutch/brake device.

[Conventional technology]

The friction plates in conventional electromagnetic clutch/brake devices have been completely dry friction, completely wet friction submerged in oil, or in rare cases only immersed in oil.

[Problem that the invention seeks to solve]

The clutch/brake friction plate in a general friction clutch/brake device has a friction coefficient of 1 to 1.
It is about 4×10 ^-7 cm ³ /Kgm, and in general, the amount of work on the surface, that is, the energy consumed by the surface, wears out linearly, and due to the wear of the friction plate, the work is transferred from the primary side to the secondary side. It will be transmitted to

However, if the friction plate were to wear out linearly due to the accumulation of work on the surface, it would be a problem as a machine. This is because the magnetic attraction surface, magnetic flux path, and friction surface are structurally integrated on both the clutch side and the brake side, and the magnetic attraction gap and friction surface gap cannot be independently adjusted in dimension in the operating direction. Moreover, in a machine designed so that the metal surfaces of the magnetically attracting surfaces do not come into contact with each other when the friction surfaces are pressed together to transmit torque, a significantly longer life than that of a general friction plate is required.

When such a machine, that is, a motor with an electromagnetic clutch and brake (see Figure 1 below), is used as a drive motor for an industrial sewing machine, for example, the motor output will be 400 to 500 W, and considering the marketability of the motor, Friction plates are generally required to have a lifespan of two years or more. Calculating this backwards from the workload of the sewing machine, which starts and stops approximately 10,000 times a day, the wear rate of the friction plate is 0.3.
It needs to be better than ×10 ^-7 cm ³ /Kg.

In addition, market demands for sewing work include operating noise of electromagnetic clutch/brake devices, odor when the temperature of the friction plate rises, clutch noise caused by the friction plate and its mating member, the clutch plate or brake plate, and the squeal that occurs during brake operation. Sound and the like particularly reduce the commercial value of the motor.

Furthermore, a motor with an electromagnetic clutch/brake device for driving a sewing machine is equipped with a controller to excite the clutch and brake coil to perform continuously variable speed or program speed control, and when the friction plate wears out, the clutch , in braking action,
The initially set acceleration/deceleration characteristics become distorted, making it impossible to achieve smooth continuously variable speed or programmed speed control.

Friction materials that satisfy long life requirements and other characteristic requirements for friction materials related to these friction plates cannot be found in organic friction materials using asbestos or the like or inorganic friction materials using sintered materials. This is because there is a limit to dry friction. Therefore, it is necessary to actively move the friction surface toward boundary friction and fluid friction. There is a need to move towards so-called wet friction clutches and brakes.

However, such a wet process requires a complex structure and lacks productivity.

In other words, for wet friction clutches and brakes that are completely submerged in oil such as lubricating oil,
Although it is expected that the lifespan of the electromagnetic clutch/brake device will be longer than that of the dry type described above, this is due to the fact that it is difficult to configure the electromagnetic clutch/brake device to operate completely in oil, and it is configured to drip oil. However, the structure is very complicated and the manufacturing cost is high.

The present invention solves the drawbacks of the prior art, and uses a flexible cork with internal holes and an appropriately regulated surface roughness impregnated with a specific oil to serve as a friction plate. In addition, it is made of cork material whose surface is coated with grease containing a mixture of the same type of oil as this impregnated oil and a solid lubricant with a specific particle size distribution, and the metal material related to the clutch plate or brake plate is By using carbon steel with a rough surface, it is easy to manufacture, and the life of the clutch friction plate or brake friction plate, clutch plate or brake plate is extended, and the noise and odor of the clutch and brake operation are reduced. The object of the present invention is to provide an electromagnetic clutch/brake device which can reduce squealing noise, improve usability for the user, and have a long life.

[Means for solving problems]

To achieve the above object, the electromagnetic clutch/brake device according to the present invention has a structure including a clutch plate attached to a flywheel attached to the shaft of the motor, and a brake plate fixed to the frame of the motor. In between, a clutch armature provided with a clutch friction plate facing the clutch plate and a brake armature provided with a brake friction plate opposed to the brake plate are moved to a spline integrated with the output shaft. A yoke containing a clutch coil and a brake coil is disposed on the outer periphery of the clutch plate and brake plate, and the magnetic flux generated by energizing the clutch coil moves and attracts the clutch plate. The clutch friction plate of the clutch armature transmits the rotation of the motor to the output side via the flywheel, and the brake friction plate of the brake armature, which is attracted to the brake plate by energizing the brake coil, outputs the motor rotation. In an electromagnetic clutch/brake device that applies a brake to a shaft, the clutch friction plate or brake friction plate described above is made of a flexible material with a surface roughness of 3 to 3 with holes inside.
A cork sized to 50μ is impregnated with paraffin-based mineral oil, and the same type of oil as this impregnated oil is used.
It is composed of a cork material whose surface is coated with a grease made of a mixture with a solid lubricant containing particles in which 50% or more of the particle size distribution is regulated to 3μ or less, and the metal related to the clutch plate or brake plate mentioned above. The material is carbon steel, and the surface roughness of the friction surface is in the range of 0.5 to 3μ.

[Effect]

As a solution to the above problem, although it is not a completely wet method, a third substance is actively interposed on the friction surface of the dry friction method, and the external structure is similar to the dry friction structure, creating a mechanism with good productivity. Research on this method has been progressing. As a result, instead of using commonly used hard materials such as asbestos, molded materials, or sintered materials, the friction material is made of cork, nonwoven fabric, etc., which have pores inside and can be impregnated with liquids such as oil. It has been found that materials with high flexibility are effective.

In other words, when these materials are used dry without any treatment, the wear rate is 5 to 15 × 10 ^-7
cm ³ /Kg, and is more abrasive and less practical than the general materials mentioned above, but by taking advantage of its impregnable property, it is impregnated with non-volatile mineral oil or silicone oil, and these oily content and graph The wear rate can be dramatically improved by applying grease mixed with a solid lubricant such as Aite or molybdenum to the surface of the friction material and using it as the third substance on the friction surface.

Furthermore, with the above configuration, it is easy to manufacture and can ensure a high coefficient of friction, and at the same time, the compatibility is improved by using a mixture of the same type of oil as the impregnating oil as the grease applied to the cork surface.
We have developed a clutch friction plate or brake friction plate that maintains the desired performance for many years without scattering or peeling, as well as a long service life of the clutch plate or brake plate. The present invention provides an electromagnetic clutch/brake device that reduces operating noise, odor, squealing noise, etc. during operation.

〔Example〕

Embodiments of the present invention will be described with reference to the respective figures. That is, FIG. 1 shows the upper half of a motor with an electromagnetic clutch and brake equipped with an electromagnetic clutch and brake device according to an embodiment of the present invention. It is a partially omitted vertical cross-sectional view.

In the figure, 1 is a motor shaft, 2 is a flywheel, 3 is a clutch plate, 4 is an output shaft, 5 is a spline, and 6 is a clutch armature.
7 is a clutch friction plate, and 8 is a clutch friction surface. Also, 9 is the brake armature, 10
is a brake friction plate, 11 is a brake friction surface,
12 is a brake plate. Note that 13 is a yoke, 14 and 15 are a clutch coil and a brake coil, 16 and 17 are a clutch magnetic flux and a brake magnetic flux, and 19 is a magnetic attraction surface.

That is, between a clutch plate 3 attached to a flywheel 2 attached to a motor shaft 1 and a brake plate 12 fixed to a motor frame (not shown), there is a clutch plate 3 facing the clutch plate 3. Clutch armature 6 equipped with friction plate 7
and a brake armature 9 provided with a brake friction plate 10 facing the brake plate 12 are movably placed side by side on the spline 5 integrated with the output shaft 4, and the clutch plate 3 and the brake plate 12 are A yoke 13 containing a clutch coil 14 and a brake coil 15 is disposed on the outer peripheral side of the yoke 13.

With the above configuration, the clutch coil 1
The clutch friction plate 7 having the clutch friction surface 8 and the clutch plate 3 provided on the clutch armature 6 which moves along the spline 5 of the output shaft 4 and is attracted by the clutch magnetic flux 16 caused by the energization of the clutch plate 3 The rotation of the motor is transmitted to the output shaft 4 via the flywheel 2 provided on the motor shaft 1, and the brake magnetic flux 17 generated by energizing the brake coil 15 causes the motor to move along the spline 5 of the output shaft 4. A brake is applied to the output shaft 4 by a brake friction plate 10 having a brake friction surface 11 and a fixed brake plate 12 provided on a brake armature 9 that is attracted.

As the friction material for the clutch friction plate 7 or the brake friction plate 10, as mentioned earlier, the following material was used on flexible cork with internal holes and a surface roughness of 3 to 50μ. A cork material that is impregnated with oil and whose surface is coated with a grease made of a mixture of the same type of oil as the impregnated oil and a solid lubricant containing particles in which 50% or more of the particle size distribution is regulated to 3μ or less. The impregnating oil is paraffinic mineral oil, and the solid lubricant is, for example, kraftite.

Further, the metal material of the clutch plate 3 or brake plate 12, which is the mating metal of the clutch friction plate 7 or brake friction plate 10, is made of carbon steel whose friction surface has a surface roughness in the range of 0.5 to 3μ. .

This is a surface roughness that does not pose any problem in actual machining.
In addition, it specifies the material and surface roughness of the clutch plate or brake plate that can be used as a partner for cork to maintain wear resistance and friction coefficient.
Regarding the suitability of 0.5 to 3 μ, please refer to Section 4 to
The experimental results shown in FIG. 6 will be described later.

In addition, the flexibility of the cork related to the above friction plate is
The flexibility that ordinary cork has, i.e.
It has a JIS shore hardness of about 50 to 100, and compared to hard asbestos, it can be expected to reduce operating noise during a collision, and has a surface roughness of 3 to 50μ. The practical limits of normal surface roughening processing and polishing of cork are taken as the range of surface roughness.

In the above, the cork itself, which is the friction material for the clutch friction plate 7 or the brake friction plate 10, is impregnated with a lubricating oil such as paraffin-based mineral oil from the outside, and a lubricating oil of the same type as the lubricating oil and a solid lubricant are also added. A good form of wear can be obtained by applying a mixture of grease to the surface.If the same type of lubricant is not used as above, the affinity between the internal impregnating oil and the surface grease will be poor, making it difficult to use. After that, scattering and peeling occur immediately, making it impossible to achieve the intended purpose.

Next, the adoption of these configurations will be explained in detail.

Here, Figure 2 shows the relationship between the amount of wear (%) of friction plates such as clutch friction plates and brake friction plates and the number of device operations (%) related to electromagnetic clutch/brake devices based on experimental results. This is a diagram explaining the characteristics of conventional materials belonging to well-known technology and related to the above-mentioned dry friction clutches/brakes. The electromagnetic clutch/brake device will wear out linearly, and the life of the electromagnetic clutch/brake device will come to an end within a short period of time. In other words, it is explained that the _b1 region (initial dimensional compression) is extended as it is, leading to wear and tear, and wear occurs in a short period of time compared to the intended lifespan (100%).

Furthermore, as mentioned above, the magnetic attraction gap has the disadvantage that the friction plates are subject to large changes due to wear, causing the speed change control characteristics to become erroneous.

On the other hand, solid line B represents the ideal wear condition sought by the inventors.

If a third substance such as impregnating oil or surface coating agent is actively interposed in the cork as in the above case, the range will change from _b1 area to _b2 area (dimensional stability period).
For long-term operation, power is transmitted while protecting the friction surface of the friction plate with impregnated oil and surface-applied grease. Thereafter, as the impregnated oil and grease disappear, the wear pattern becomes similar to that of the conventional material (dry type) described above, and this shows a change in the amount of wear of the friction plate that satisfies the predetermined life span.

As shown by line B in the figure, at the beginning of the range where the number of operations is small, friction plate wear is measured as shown in _b1 , but this is essentially dimensional compression of the cork material. , not wear. and,
When the compression of the material settles down, the third substance scatters,
As long as there is no wear, the dimensional change of the friction plate becomes almost zero, as shown by b ₂ in the figure.

Its long life depends on the amount and quality of the oil impregnated into the cork, how it seeps out, the quality and amount of the grease applied to the surface, the mating metal, other environment, load conditions, etc. Direct friction between the cork friction material and the mating metal begins due to the complete consumption of the impregnating oil and the scattering and abrasion of the surface coating agent, that is, the disappearance of the third substance, resulting in the friction material shown in the figure.
As shown in b ₃ , the wear ends in a straight line at the point where it begins.

The number of times the device operates (%) above is
It means a relative comparison of the number of operations, and 100
% is the resulting lifespan of the device, this is an illustration to explain that wear is extremely low on the way to that end.

In such a life characteristic, in the range b ₁ and b ₂ along line B in the figure, the gap in magnetic attraction is
Almost constant and stable shifting characteristics are obtained, and the friction coefficient of the friction plate is 0.3 ×
A value of 10 ^-7 cm ³ /Kgm or better can be obtained and is suitable for the intended use.

From the above, it is important to determine how long the b ₂ area mentioned above is, and the factors contributing to this are the particle size of the solid lubricant in the grease and the surface roughness of the mating metal surface that engages with the friction plate. .

Therefore, it has been experimentally found that there is a particle size range of the solid lubricant and a range of surface roughness of the mating metal surface that are most suitable for the intended purpose.

That is, FIG. 3 is an example showing the particle diameter distribution of solid lubricants such as molybdenum disulfide, Teflon, and graphite.
More than 80% of the particles have a particle size of 1μ or less.

FIG. 4 shows an example of the coefficient of kinetic friction when a cork friction material is treated using graphite having such a particle size distribution as the solid lubricant and paraffinic mineral oil as the oil. The horizontal axis in FIG. 4 indicates the surface roughness of carbon steel when carbon steel is used as the mating friction surface. According to this experiment, it can be seen that the coefficient of friction decreases when the surface of the mating metal becomes 0.3μ.

That is, Fig. 4 shows the relationship between the friction coefficient of a wet friction plate obtained by mixing the solid lubricant illustrated in Fig. 3 with paraffinic mineral oil and applying it to a dry friction plate, and the surface roughness of the mating metal surface. The important point here is that when the surface roughness of the mating metal is 0.3 μ or less, the coefficient of friction decreases.

In general, in friction between hard materials, surface roughness does not significantly affect the coefficient of friction. No. 2, February 1971), it has become publicly known.

However, as mentioned above, in a friction material made of cork impregnated with oil and coated with a surface coating agent, a mirror surface that is too finished deteriorates the friction characteristics.

As is well known, the generation of so-called frictional force is said to be due to the mechanism of excavation of surface irregularities and the adhesion mechanism of materials on the contact surface. Wear is caused by the destruction of the material due to the above two mechanisms.
This is due to withdrawal.

As is well known, carbon, which is in the form of graphite, is a crystalline solid consisting of layers of hexagonal ring network planes made only of carbon atoms, and the bond between the layers is weak, making it difficult to resist shearing forces. When subjected to such damage, it tends to slip or peel off, resulting in a scaly appearance. Chemically, it is also an extremely stable substance and has high heat resistance. Molybdenum disulfide and Teflon are also substances with similar but slightly different properties.

As is well known, these substances are used as solid lubricants, but the friction material of the present invention has the contradictory effect of contributing to longer life through its lubricity while not impairing the high friction coefficient characteristics unique to cork. It is based on the dual existence of matters to be carried out.

In this case, the oil is the retention of the solid lubricant in powder form and contributes to its strong adhesion to the cork surface, so the consumption of oil is due to the restoration of the solid lubricant to the powder form, the dispersion, As a result, as explained in FIG. 2, linear wear of the friction material occurs.

Now, in such a friction surface, as shown in Fig. 4, if the surface roughness of the mating metal surface is small, the friction coefficient decreases because the mechanism of friction force generation is due to the upheaval and adhesion. However, these are thought to be influenced by the surface roughness of the cork, the presence of oil, and solid lubricant.

As experimental results related to this, the results shown in FIGS. 5 and 6 will be explained.

Figure 5 shows the surface roughness of cork after friction operation for a certain period of time under the conditions described above in connection with Figure 2, and the surface roughness before the test is 55μ. . This indicates that when the average surface roughness of cork significantly exceeds this value, a phenomenon of peeling of cork particles occurs, resulting in a shortened lifespan.

In other words, Figure 5 shows how the surface roughness of the dry friction material (cork), which had an initial temperature of 55 μm, changed after operation when a dry friction material (cork) with an initial temperature of 55 μm was tested using a dry friction material whose friction surface had not been treated in any way and a mating metal. This indicates whether the value has changed. When the surface roughness of the mating metal is small (0 to 3
In the metal surface roughness region of μ), the cork surface roughness is 42
When the surface roughness of ~32μ is close to the initial surface roughness of 55μ, and the surface roughness of the mating metal is large (more than 3μ), the initial surface roughness of cork of 55μ changes significantly from 20 to 10μ compared to the initial surface roughness. In other words, when the surface roughness of the mating metal is large, the surface of the dry friction plate (cork) is ground, and the surface roughness of the cork and the metal surface are similar, and the surface roughness of the mating metal surface is If it is small, it means that the ratio of grinding the opposing cork surface is small. In other words, it is shown that cork wear is less likely to occur in a region where the surface roughness of the mating metal surface is 3μ or less. According to FIG. 5, the smaller the surface roughness of the mating metal surface shown on the horizontal axis, the closer the cork surface is to the surface roughness before the test. That is, it can be seen that the cork surface is not ground by the surface of the mating metal.

Considering the results in FIGS. 4 and 5, it can be seen that there is a range of metal surface roughness in which the coefficient of friction is maintained and cork wear is small.

Next, FIG. 6 shows the results of testing the wear rate of the cork material under the conditions described in FIGS. 4 and 5 and further changing the graphite particle size distribution.

In other words, in Figure 6, the horizontal axis shows the surface roughness of the mating metal surface, and the vertical axis shows the wear rate (the value obtained by dividing the amount of wear by the unit work), and the parameters are:
This is the particle size of the solid lubricant applied to the dry friction material. In other words, the particle distribution shown in Figure 3 is 50%
Data are shown for P, Q, and R materials with particle diameters of 1 μ or less, 3 μ or less, and 5 μ or less. As is clear from the figure, the P material (solid lubricant with particle size distribution of 1μ or less is 50% or more)
The wear is the smallest, and the wear increases in order of P, Q, and R. Further, the wear rate is constant for P, Q, and R until the surface roughness of the mating metal exceeds 2μ, but the wear rate increases rapidly when the surface roughness exceeds 2μ.

In other words, the larger the particle diameter, the higher the wear rate, but as the surface roughness of the mating metal surface increases, this difference disappears, indicating that wear increases in both cases. Further, although not shown, even if the particle size of graphite was increased, the characteristics of lowering the coefficient of friction with low surface roughness as shown in FIG. 4 remained the same.

In addition, molybdenum disulfide other than graphite,
The test results for Teflon solid lubricants are also very similar.
It has similar characteristics as shown in Figures 4-6.

The following conclusions can be drawn from the experimental results shown in FIGS. 1 to 6 above.

(1) If the surface roughness of the mating metal surface is 0.3μ or less,
The coefficient of friction decreases, causing problems with gear shifting characteristics, etc.

(2) If the surface roughness of the mating metal is 2μ or more, the wear rate of the surface-treated friction material will be high.

From these (1) and (2), the roughness of the mating metal surface is 0.3μ to 2μ, but considering mass production, 0.5μ to 3μ is appropriate as the surface roughness of the mating metal surface.

(3) Also, the optimum particle size of the solid lubricant is 1μ or less, but if 50% or more of the particle size is 3μ or less (Q or less in Figure 6), the surface roughness of the mating metal surface The wear rate of the 5μ (R in FIG. 6) is twice as high as that of the 3μ. If it is about 3μ (or less), mass production can be ensured.

(4) Furthermore, if the mating metal is 3μ or less, even cork without any surface treatment will experience little wear. The surface roughness of cork is kept within the range of 3 to 50 microns, which is the practical limit of normal surface roughening processing and polishing of cork.

As described above, in the present invention, the optimal regulation conditions were determined through numerous experiments, and it is only through the interaction of all regulation conditions that a high-performance device can be provided. be.

That is, as described above, a clutch friction plate or a brake friction plate is made by impregnating a flexible cork with internal pores and a surface roughness of 3 to 50 μm with paraffinic mineral oil, and then impregnating it with an oil of the same type as this impregnated oil. , more than 50% of the particle size distribution is 3μ
It is made of cork material whose surface is coated with a grease made from a mixture of solid lubricant containing particles regulated below, and the metal material for the clutch plate or brake plate is carbon steel, and the surface roughness of the friction surface is is in the range of 0.5 to 3μ.

As a result of the above, a product with the characteristics shown in Figure 2B was obtained, and it was easy to manufacture and ensure a high coefficient of friction. At the same time, it was possible to use the same type of impregnating oil as the grease to be applied to the cork surface. Clutch or brake friction plates, clutch plates or brake plates that have improved affinity and can maintain the desired performance over many years without scattering or peeling. The present invention provides an electromagnetic clutch/brake device that has a longer service life and reduces operating noise, odor, squealing noise, etc. during clutch and braking.

〔Effect of the invention〕

Taking all the points mentioned above into consideration, the present invention makes it possible to provide an electromagnetic clutch/brake device comprising a high-performance friction material and a mating metal material that works inseparably from the friction material. Therefore, it can be said to be an outstanding invention that has excellent effects and is based on new knowledge and new technical ideas.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted longitudinal sectional view of a motor with an electromagnetic clutch and brake, which is an embodiment of the present invention.
Figure 2 is an explanatory diagram of friction plate wear characteristics, Figure 3 is an explanatory diagram of solid lubricant particle size distribution, and Figures 4, 5, and 6 are surface roughness, friction coefficient, surface roughness, and lining surface roughness, respectively. FIG. 3 is an experimental result curve diagram of surface roughness, surface roughness, and wear rate. 3...Clutch plate, 6...Clutch armature, 7...Clutch friction plate, 9...Brake armature, 10...Brake friction plate, 12...Brake plate.

Claims (1)

[Claims] 1. A clutch armature that is provided with a clutch friction plate facing the clutch plate between a clutch plate attached to a flywheel attached to the shaft of the motor and a brake plate fixed to the frame of the motor. A brake armature provided with a brake friction plate facing the brake plate is movably placed side by side on a spline integrated with the output shaft, and a clutch coil is disposed on the outer periphery of the clutch plate and the brake plate. A yoke with a built-in brake coil is arranged, and the clutch friction plate of the clutch armature, which is moved and attracted to the clutch plate by the magnetic flux generated by energizing the clutch coil, outputs rotation of the motor via the flywheel. In an electromagnetic clutch/brake device that applies a brake to the output shaft by the brake friction plate of the brake armature, which is transferred to the shaft and moved to the brake plate by energization of the brake coil, the brake friction plate or The brake friction plate is made by impregnating a flexible cork with internal holes and a surface roughness of 3 to 50 μm with paraffin-based mineral oil, and using the same type of oil as this impregnated oil and its particle size distribution. It is composed of a cork material whose surface is coated with a grease made of a mixture with a solid lubricant containing particles whose size is 50% or more regulated to 3μ or less, and the metal material related to the clutch plate or brake plate is carbon steel, An electromagnetic clutch/brake device characterized in that the friction surface has a surface roughness in the range of 0.5 to 3μ.