JP7244073B2 - torque limiter - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter used in paper feeders such as copiers, printers and facsimiles, and ATMs.

FIG. 8 shows a multifeed prevention mechanism of a paper feeder used in a copier or the like. In FIG. 8, the friction roller 101 is pressed against the feeding roller 102 with a predetermined pressure. Torque T is applied to the friction roller 101 via a torque limiter 100 in a direction to return the paper 103 . The torque limiter 100 transmits rotation from the driving side, i.e., the shaft 104, to the driven side, i.e., the friction roller 101, within the range of a predetermined torque value Ta. It has the function of blocking transmission. The predetermined torque value Ta is set to a value greater than the frictional force between sheets and less than the rotational force of the feeding roller 102 .

Therefore, as shown in FIG. 8A, when two or more sheets of paper 103 are guided between the feed roller 102 and the friction roller 101, the second and subsequent sheets are separated from the first sheet. The paper 103 is returned in the direction opposite to the traveling direction. However, as shown in FIG. 8B, when the feeding roller 102 and the friction roller 101 are in direct contact or in contact with only one sheet of paper 103 therebetween, the rotation of the friction roller 101 is limited by the torque limiter. Rotation of the shaft 104 is blocked by the function of 100, and the friction roller 101 rotates together with the feeding roller 102. FIG.

In this way, the paper 103 is fed out one by one from the paper feeder. The torque limiter 100 is required to have a stable predetermined torque value Ta in order to reliably feed the sheets 103 one by one from the paper feeder.

Japanese Patent Application Laid-Open No. 6-235447 (Patent Document 1) is known as a torque limiter that utilizes hysteresis torque and is used in such a sheet feeding device. As shown in FIG. 9 , the torque limiter 200 of Patent Literature 1 includes a first rotating body 210 and a second rotating body 220 . First rotating body 210 includes rotating shaft 211 and permanent magnet 212 , and second rotating body 220 includes housing 221 , hysteresis material 222 and lid portion 223 . The lid portion 223 is provided so as to close the opening of the housing 221 . Sliding portions 231 and 232 are provided between the first rotating body 210 and the second rotating body 220 , and the torque limiter 200 has two sliding portions 231 and 232 . Both the diameters of the sliding portions 231 and 232 are smaller than the outer diameter dimension of the permanent magnet 212 .

Further, in Japanese Patent Laying-Open No. 2008-281112 (Patent Document 2) and Japanese Patent Laying-Open No. 10-78043 (Patent Document 3), both the diameters of the sliding portions of the first rotating body and the second rotating body are A torque limiter is disclosed that is smaller than the outer diameter of the permanent magnet of the rotating body.

JP-A-6-235447 JP 2008-281112 A JP-A-10-78043

In Patent Documents 1 to 3, since the diameter of the sliding portion is smaller than the outer diameter of the permanent magnet of the first rotating body, the hysteresis material and the permanent magnet come into contact when the torque limiter rotates, resulting in instability. There is a problem that it becomes a large torque.

SUMMARY OF THE INVENTION An object of the present invention is to provide a torque limiter capable of providing stable torque.

A torque limiter according to an aspect of the present invention is relatively rotatable coaxially with a rotating shaft and a first rotating body including either a permanent magnet or a hysteresis material attached to the outer peripheral surface of the rotating shaft. and a second rotating body attached to the inner peripheral surface of the housing and including one of the permanent magnet and the hysteresis material and the other of the permanent magnet and the hysteresis material facing across a gap, wherein the first rotating body and the housing of the second rotor have a sliding portion that slides in the circumferential direction, and the diameter of the sliding portion is the same as the outer diameter of one of the permanent magnets or the hysteresis material of the first rotor. or greater.

Preferably, the diameter of the sliding portion is the same as or smaller than the inner diameter of the permanent magnet of the second rotating body or the other of the hysteresis material.

Preferably, the radial dimension of the gap between the permanent magnet and the hysteresis material is 0.2 mm or less.

Preferably, a plurality of sliding portions are provided so as to sandwich one of the permanent magnet and the hysteresis material of the first rotating body from both sides in the rotation axis direction.

According to the torque limiter of the present invention, stable torque can be provided.

1 is a cross-sectional view schematically showing a torque limiter according to Embodiment 1 of the present invention; FIG. 1 is a cross-sectional view schematically showing a torque limiter according to Embodiment 1 of the present invention, and is an enlarged view of a portion indicated by II in FIG. 1. FIG. FIG. 6 is a cross-sectional view schematically showing a torque limiter according to Embodiment 2 of the present invention; 4A is an enlarged view of the portion indicated by IV(a) in FIG. 3, and FIG. ) is an enlarged view of the portion indicated by . 2 is a graph showing the relationship between time and torque value for an example and a comparative example, where (a) is a graph showing the torque value of the example when the paper passing operation is not performed, and (b) is a graph showing the torque value when the paper passing operation is performed. 10 is a graph showing torque values of a comparative example when no 2 is a graph showing the relationship between time and torque value for an example and a comparative example, where (a) is a graph showing the torque value of the example after 1,000,000 paper-passing operations, and (b) is 1,000,000 times. 10 is a graph showing torque values of a comparative example after a paper-passing operation; 2 is a graph showing the relationship between time and torque value for an example and a comparative example, where (a) is a graph showing the torque value of the example after 2,000,000 paper-passing operations, and (b) is 2,000,000 times. 10 is a graph showing torque values of a comparative example after a paper-passing operation; FIG. 4 is a diagram showing a specific usage example of the torque limiter, (a) is a schematic diagram when the second and subsequent sheets of paper are returned in the direction opposite to the traveling direction, and (b) is a diagram showing one sheet sandwiched FIG. 4 is a schematic diagram of a case where a friction roller and a feed roller rotate together; 1 is a cross-sectional view schematically showing a general torque limiter; FIG.

Embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same reference numerals are given to the same or corresponding parts in the drawings, and the description thereof will not be repeated.

(Embodiment 1)
First, a torque limiter according to Embodiment 1 of the present invention will be described. FIG. 1 is a sectional view schematically showing a torque limiter 1 according to Embodiment 1 of the present invention. The arrow A1 indicates the rotation axis direction (hereinafter referred to as "axial direction"), the direction indicated by the arrow A1 is called one direction, and the direction opposite to the arrow A1 is called the other direction. Arrow A2 indicates the radial direction.

Referring to FIG. 1, a torque limiter 1 according to the first embodiment includes a first rotor 10 integrally rotated with a drive shaft (not shown) via a set screw, and a first rotor 10. It has a rotating body 10 and a second rotating body 20 that is rotatably provided relative to the rotating body 10 .

First rotating body 10 of the present embodiment has rotating shaft 11 and cylindrical permanent magnet 12 attached to the outer peripheral surface of rotating shaft 11 .

A synthetic resin is preferably used as the material of the rotating shaft 11 . Examples of synthetic resins include polyacetal resin, polybutylene terephthalate resin, polyamide resin, polyolefin resin, polyimide resin, polycarbonate resin, polyetheretherketone resin, polypropylene resin, polyetherimide resin, liquid crystal polymer, polyethernitrile resin, polyether Ketone resins, polyphenylene sulfide resins, polyphenylene oxide resins, phenol resins, epoxy resins, acrylonitrile-butadiene-styrene resins, and the like. As the material of the rotating shaft 11, for example, metal may be used as a material other than the synthetic resin. Examples of metals include aluminum, zinc, brass, stainless steel, and iron.

The rotating shaft 11 includes, for example, a cylindrical first shaft portion 30 extending in the axial direction, a first portion 31 protruding from the outer peripheral surface of the first shaft portion 30 toward the outer diameter side, and the first portion 31. A second portion 32 extending from the outer diameter side end toward one end in the axial direction, a third portion 33 projecting from the one axial end of the second portion 32 toward the outer diameter, and a third A fourth portion 34 extending from the outer diameter side end portion of the portion 33 toward one end side in the axial direction is provided. With such a configuration, the rotary shaft 11 has a stepped protrusion.

The first shaft portion 30 is attached so as to surround the outer circumference of a drive shaft (not shown). The first portion 31 protrudes from the central portion of the first shaft portion 30 in the axial direction. The second portion 32 is provided parallel to and spaced from the first shaft portion 30 . A permanent magnet 12 is attached to the outer peripheral surface of the second portion 32 . The third portion 33 is provided so as to extend to a position protruding from the outer peripheral surface of the permanent magnet 12 . The fourth portion 34 is provided parallel to and spaced from the first shaft portion 30 . The outer diameter of the fourth portion 34 is larger than the outer diameter dimension of the permanent magnet 12 and is the first sliding portion 13 that slides in the circumferential direction with respect to the second rotating body 20 . One end of the fourth portion 34 extends to a position where it abuts on a first side wall portion 41 of the second rotating body 20 , which will be described later, and is located closer to the one end than the one end of the first shaft portion 30 . With such a configuration, the space between the first shaft portion 30 and the second portion 32 and between the first shaft portion 30 and the fourth portion 34 are hollow.

A ferrite magnet, a sintered magnet, a resin magnet, a rare earth magnet, or the like is used as the permanent magnet 12, but it is desirable to use a rare earth magnet from the viewpoint of miniaturization and high torque of the torque limiter. As rare earth magnets, for example, Nd--Fe--B magnets, Sm--Fe--N magnets, Sm--Co magnets, etc. are used.

The second rotating body 20 of the present embodiment is attached to a housing 21 which is relatively rotatable on the same axis as the rotating shaft 11, and the inner peripheral surface of the housing 21, and is separated from the permanent magnet 12 by a gap G. and cylindrical hysteresis members 22 facing each other.

The material of the housing 21 is preferably the same as that of the rotary shaft 11, such as synthetic resin or metal. The housing 21 is attached to, for example, a friction roller and has a cylindrical second shaft portion 40 extending in the axial direction, and a first side wall portion provided so as to extend radially outward from one end of the second shaft portion 40 . 41 , and an outer peripheral portion 42 extending from the outer diameter side end portion of the first side wall portion 41 toward the other end side and provided so as to surround the first rotor 10 .

The second shaft portion 40 is provided so as to be close to one end of the first shaft portion 30 of the rotating shaft 11 . One end surface of the first side wall portion 41 is located on the friction roller side. The other end surface of the first side wall portion 41 contacts one end portion of the fourth portion 34 .

The outer peripheral portion 42 includes, for example, a first outer peripheral portion 43 extending from the outer diameter side end portion of the first side wall portion 41 toward the other side, and an inner diameter dimension smaller than that of the first outer peripheral portion 43 . A second outer peripheral portion 44 further extends from the other end toward the other side. With such a configuration, the outer peripheral portion 42 has a step on the inner peripheral surface.

The inner diameter of the first outer peripheral portion 43 is smaller than the inner diameter dimension of the hysteresis member 22 , and the second sliding portion 23 slides in the circumferential direction with respect to the first sliding portion 13 . A hysteresis member 22 is attached to the inner peripheral surface of the second outer peripheral portion 44 so as to face the permanent magnet 12 .

Housing 21 has an opening at the other end, and lid 24 is provided to close the opening. Outer peripheral portion 42 has a recess for fitting with lid portion 24 at the other end of second outer peripheral portion 44 . As a result, the lid portion 24 is fixed to the second outer peripheral portion 44 by the concave-convex fitting. The material of the lid portion 24 is preferably the same material as that of the rotary shaft 11, such as synthetic resin or metal. The lid portion 24 and the rotating shaft 11 slide in the circumferential direction on the end surfaces 24a and 24b that contact each other.

The hysteresis member 22 is provided at a position facing the permanent magnet 12 of the first rotating body 10 with a gap G therebetween. The hysteresis material 22 is made of a metal material having a high residual magnetic flux density and a certain degree of coercive force. As the hysteresis material 22, for example, an Al--Ni--Co system alloy, Fe--Co system alloy, Fe--Cr--Co system alloy, Fe--Mn system alloy, Fe--Ni system alloy or the like is used.

FIG. 2 is a cross-sectional view schematically showing the torque limiter according to Embodiment 1 of the present invention, and is an enlarged view of the portion indicated by II in FIG. The gap G has a radial dimension of less than 0.3 mm, preferably less than or equal to 0.25 mm. From the viewpoint of improving the torque, it is more preferably 0.2 mm or less, and from the viewpoint that the radial dimension of the gap G is preferably as small as possible, it is much more preferably 0.15 mm or less. The gap G in this embodiment has a radial dimension of 0.15 mm. The radial dimension is the radial dimension of the gap G on one side when the boundary is the axis O indicated by the dashed line in the cross-sectional view shown in FIG. Moreover, the dimension in diameter is a value obtained by combining the dimensions of both gaps G in the radial direction when the axis O is used as a boundary.

Next, the first sliding portion 13 and the second sliding portion 23 will be described. As described above, the rotating shaft 11 of the first rotating body 10 and the housing 21 of the second rotating body 20 have the first and second sliding portions 13 and 23 that slide in the circumferential direction (rotational direction). The first and second sliding portions 13 and 23 are plain bearing portions that rotatably support the rotating portions of the first rotating body 10 and the second rotating body 20 . Sliding means that the rotating shaft 11 and the second rotating body 20 move relatively while being in contact with each other. Note that there may be a slight gap between the first sliding portion 13 and the second sliding portion 23 .

Synthetic resin is used for the material of the first and second sliding parts 13 and 23, and they are part of the rotary shaft 11 and the housing 21, respectively. However, as the material of the first and second sliding portions 13 and 23, a material different from that of the rotating shaft 11 and the housing 21 may be used. The synthetic resin used for the first and second sliding portions 13 and 23 is suitable for those having excellent slidability, heat resistance, dimensional stability, a high grade with a high limit PV value, and excellent strength. In addition, the synthetic resin used for the first and second sliding portions 13 and 23 may further contain a filler in order to improve slidability, rigidity, PV value, and the like. Materials suitable for fillers include, for example, potassium titanate whiskers, tetrafluoride resin (PTFE), solid lubricants (eg, graphite, molybdenum disulfide, etc.), oils, glass beads, and the like.

In the first and second sliding portions 13 and 23, the fourth portion 34 of the rotating shaft 11 and the first outer peripheral portion 43 of the housing 21 are in contact with each other and slide while rubbing against each other. A diameter R1 of the first and second sliding portions 13 and 23 is larger than an outer diameter dimension R2 of the permanent magnet 12 of the first rotor 10 . Moreover, it is desirable that the diameter R1 of the first and second sliding portions 13 and 23 is smaller than the inner diameter dimension R3 of the hysteresis member 22 of the second rotating body 20 . That is, it is preferable that the diameter R1 of the first and second sliding portions 13 and 23 is larger than the outer diameter R2 of the permanent magnet 12 and smaller than the inner diameter R3 of the hysteresis member 22 .

In all conventional torque limiters, the diameter of the sliding portion is smaller than the outer diameter of the permanent magnet. Therefore, there is a problem that the first rotor wobbles during operation of the torque limiter, and the permanent magnet and the hysteresis material come into contact with each other. In the torque limiter 1 according to the present embodiment, since the diameter R1 of the first and second sliding portions 13 and 23 is larger than the outer diameter dimension R2 of the permanent magnet 12 of the first rotating body 10, the torque limiter 1 can be used. Occasional wobbling of the first rotating body 10 can be suppressed. Therefore, since the torque limiter 1 according to the present embodiment can stably rotate the first rotating body 10 and the second rotating body 20, it is possible to prevent the gap G from fluctuating. contact can be prevented. Thereby, torque can be stabilized.

In the torque limiter 1 according to this embodiment, the diameter R1 of the first and second sliding portions 13, 23 is smaller than the inner diameter dimension R3 of the hysteresis member 22 of the second rotor 20. As shown in FIG. That is, in the torque limiter 1 , the hysteresis member 22 of the second rotor 20 does not protrude further to the inner diameter side than the first and second sliding portions 13 and 23 . Therefore, when the first rotating body 10 is accommodated in the second rotating body 20 when manufacturing the torque limiter 1 , the first sliding portion 13 of the first rotating body 10 is not caught by the hysteresis member 22 . As a result, the torque limiter 1 according to the present embodiment can prevent contact between the hysteresis member 22 and the first sliding portion 13 of the first rotor 10, and can be easily assembled.

Further, according to the present embodiment, the radial dimension of the gap G between the permanent magnet 12 and the hysteresis material 22 is 0.2 mm or less. As described above, the torque limiter 1 according to the present embodiment can improve the torque because the dimension of the radius of the gap G is small. Furthermore, in the torque limiter 1, even if the radial dimension of the gap G is small, the permanent magnet 12 and the hysteresis material 22 do not come into contact with each other, so torque can be stabilized.

In this embodiment, the diameter R1 of the sliding portions 13 and 23 of the torque limiter 1 is set to be larger than the outer diameter R2 of the permanent magnet 12 of the first rotor 10, but this is not the only option. The diameter R1 of the sliding portions 13 and 23 may be the same as the outer diameter dimension R2 of the permanent magnet 12 of the first rotor 10 .

(Embodiment 2)
A torque limiter 1A according to the second embodiment will be described with reference to FIGS. A torque limiter 1A of the second embodiment basically has the same configuration as the torque limiter 1 of the first embodiment, but as shown in FIG. differ as to where it is provided.

A torque limiter 1A according to the second embodiment includes a first rotating body 10A and a second rotating body 20A.

The rotating shaft 11A of the first rotating body 10A has a step on its outer peripheral surface. The rotating shaft 11A has a stepped recess 36A with a small outer diameter, and first and second stepped protrusions 35A and 37A with a large outer diameter. The first and second protrusions 35A and 37A are provided so as to sandwich the recess 36A from both sides in the axial direction. That is, the first protrusion 35A is located on one axial end side of the recessed portion 36A, and the second protruding portion 37A is located on the other axial end side of the recessed portion 36A.

A permanent magnet 12 is attached to the outer peripheral surface of the recess 36A. The outer diameters of the first and second protrusions are larger than the outer diameter dimension of the permanent magnet 12 . The outer peripheral surface of the first convex portion 35A is the first sliding portion 15A that slides in the circumferential direction with respect to the second rotating body 20A. The outer peripheral surface of the second convex portion 37A is the first sliding portion 13A that slides in the circumferential direction with respect to the second rotating body 20A.

The first convex portion 35A, the concave portion 36A and the second convex portion 37A of the first rotor 10A are integrally formed. The second convex portion 37A serves as a lid portion of the torque limiter 1A. That is, the torque limiter 1A does not need to prepare a cover, and can have a dust-proof effect without providing a cover on the housing 21A.

The housing 21A of the second rotating body 20A includes a second side wall portion 45A and a second outer wall portion 46A.

One end surface of the second side wall portion 45A is positioned, for example, on the friction roller side. The other end surface of the second side wall portion 45A contacts the one end surface of the rotating shaft 11A. The second outer wall portion 46A has a step on the inner peripheral surface. The second outer wall portion 46A includes a fourth outer peripheral portion 48A having a large inner diameter dimension among the steps, and third and fifth outer peripheral portions 47A and 49A having a smaller inner diameter dimension among the steps. The third and fifth outer peripheral portions 47A and 49A are provided so as to sandwich the fourth outer peripheral portion 48A from both sides in the axial direction. That is, the fourth outer peripheral portion 48A is a concave portion of the inner peripheral surface of the second outer wall portion 46A, the third outer peripheral portion 47A is positioned on one axial end side of the fourth outer peripheral portion 48A, and the fifth outer peripheral portion 49A is positioned on the other axial end side of the fourth outer peripheral portion 48A.

A hysteresis member 22 is attached to the inner peripheral surface of the fourth outer peripheral portion 48A. The inner diameters of the third and fifth outer peripheral portions 47A and 49A are smaller than the inner diameter dimension of the hysteresis member 22 . The inner peripheral surface of the third outer peripheral portion 47A is the second sliding portion 25A that slides in the peripheral direction with the outer peripheral surface (first sliding portion 15A) of the first convex portion 35A. The inner peripheral surface of the fifth outer peripheral portion 49A is the second sliding portion 23A that slides in the circumferential direction with the outer peripheral surface (the first sliding portion 13A) of the second convex portion 37A.

Next, two sliding portions, that is, the first and second sliding portions 13A, 23A and the first and second sliding portions 15A, 25A will be described. The first and second sliding portions 13A and 23A are on the other axial side of the permanent magnet 12 and the hysteresis member 22, and the first and second sliding portions 15A and 25A are on one side of the permanent magnet 12 and the hysteresis member 22 in the axial direction. provided on the side. That is, the first and second sliding portions 13A, 23A and the first and second sliding portions 15A, 25A are provided so as to sandwich the permanent magnet 12 and the hysteresis material 22 from both sides in the axial direction.

The first and second sliding portions 15A and 25A on one side and the first and second sliding portions 13A and 23A on the other side preferably have the same diameter. However, the diameter may be different as long as the dimensions of the gap G are maintained.

The first convex portion 35A and the second convex portion 37A are provided so as to sandwich the permanent magnet 12 from both sides in the axial direction. Furthermore, the diameters of the first convex portion 35A and the second convex portion 37A are larger than the outer diameter dimension of the permanent magnet 12 . In such a configuration, the permanent magnet 12 does not protrude from the first rotating body 10A of the present embodiment. In the torque limiter 1A, the first rotating body 10A and the second rotating body 20A are separately manufactured at the time of manufacture. The permanent magnet 12 is not damaged only by the contact of the first convex portion 35A and the second convex portion 37A. In other words, damage to the permanent magnets 12 can be prevented.

In the first and second embodiments, the permanent magnet 12 is attached to the first rotating body 10 and the hysteresis member 22 is attached to the second rotating body 20, but the reverse is also possible. That is, the hysteresis material 22 may be attached to the first rotating body 10 and the permanent magnet 12 may be attached to the second rotating body 20 .

Further, in Embodiment 2, the first and second sliding portions 13A, 15A, 23A, 25A of the torque limiter 1A are provided at two locations, but may be provided at three or more locations.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these.

(Example)
The torque limiter of the example was the same as that of the first embodiment shown in FIGS. Specifically, the first rotor and the second rotor were made of synthetic resin. An Nd--Fe--B magnet was used as the permanent magnet, and an Fe--Cr--Co alloy was used as the hysteresis material. The inner diameter of the hysteresis material attached to the second rotor was 14.8 mm, the outer diameter of the permanent magnet attached to the first rotor was 14.5 mm, and the dimension at the radius of the gap was 0.15 mm. . The inner diameter of the permanent magnet attached to the first rotor was 11.6 mm, and the thickness of the permanent magnet in the radial direction was 2.9 mm. The permanent magnet had an axial dimension of 7.8 mm, a volume of 0.46 cm ³ , a density of 6.04 g/cm ³ and a weight of 2.78 g.

(Comparative example)
The torque limiter of the comparative example was basically the same as the general torque limiter shown in FIG. 9, but was used with the dimensions of the gap modified. Specifically, the first rotor and the second rotor were made of synthetic resin. An Nd--Fe--B magnet was used as the permanent magnet, and an Fe--Cr--Co alloy was used as the hysteresis material. The inner diameter of the hysteresis material attached to the second rotor was 14.67 mm, the outer diameter of the permanent magnet attached to the first rotor was 14.37 mm, and the dimension at the radius of the gap was 0.15 mm. . The inner diameter of the permanent magnet attached to the first rotating body was 11.47 mm, and the thickness of the permanent magnet in the radial direction was 2.9 mm. The permanent magnet had an axial dimension of 7.9 mm, a volume of 0.46 cm ³ , a density of 6.06 g/cm ³ and a weight of 2.79 g.

The torque limiters used in the examples and comparative examples have the same dimensions in the radius of the gap. Furthermore, the permanent magnets have substantially the same radial thickness, axial dimensions, volume, density, and weight. This made it possible to compare the torque stability of the example and the comparative example.

(Evaluation method)
The relationship between time and torque under each condition was examined for the torque limiters of Examples and Comparative Examples. Table 1 shows the dimensions and torque values of the torque limiters of Examples and Comparative Examples.

Specifically, first, the torque limiter was fixed to a shaft directly connected to the drive source of the durability testing device, and the second rotating body was fixed to the testing device so as to rotate relative to the first rotating body. Next, after starting the paper feeding device with a rotation speed of 650 rpm for 0.6 seconds, the rotation speed was set to 0 rpm, that is, the stopped state was performed for 0.2 seconds. The paper feeding operation can apply a load to the torque limiter when the paper feeding device is started. After performing the paper feeding operation for a predetermined number of times, continuous rotation was performed at 500 rpm for 30 minutes, and the relationship between the torque (mNm) value and the time (minute) was continuously measured.

(Evaluation results)
Torque values were measured using a digital force gauge (manufactured by Imada). The results are shown in Figures 5-7. 5 to 7 are graphs showing the relationship between time and torque value for the example and the comparative example, FIG. (b) shows the torque value of the comparative example when the sheet feeding operation is not performed. FIG. 6(a) shows the torque value of the example after one million times of paper-passing operation, and FIG. 6(b) shows the torque value of the comparative example after one million times of paper-passing operation. there is FIG. 7(a) shows a graph showing the torque value of the example after 2,000,000 paper-passing operations, and FIG. 7(b) shows the torque value of the comparative example after 2,000,000 times. The horizontal axis indicates time (minutes), and the vertical axis indicates torque values (mNm).

As shown in FIG. 5(a), the initial torque value was 38.2 mNm when the paper feeding operation was not performed in the example. As shown in FIG. 5(b), the initial torque value was 37.0 mNm when the sheet feeding operation was not performed in the comparative example. An initial torque value is a torque value immediately after the start of measurement.

As shown in FIGS. 5(a) and 5(b), when the paper-passing operation was not performed, there was no disturbance in the graph shape and the torque was stable in both the example and the comparative example.

As shown in FIG. 6(a), when the sheet feeding operation was performed one million times, the shape of the graph in Example was smooth and free from disturbance, and the torque was stable. However, as shown in FIG. 6B, the graph of the comparative example was disturbed and the torque was unstable. Specifically, after the start of the measurement, a turbulence such as a small zigzag fluctuation was confirmed. This is because the sliding portion is worn in the comparative example, and the permanent magnet and the hysteresis material are in contact during the paper feeding operation.

As shown in FIG. 7(a), when the sheet feeding operation was performed 2 million times, the shape of the graph in Example was smooth and free from disturbance, and the torque was stable. However, as shown in FIG. 7B, in the comparative example, the shape of the graph was greatly disturbed and the torque was unstable. Specifically, after 5 minutes from the start of the measurement, it was confirmed that the torque value increased from the initial torque, and that the torque fluctuated in a zigzag pattern. This is because the sliding portion is worn in the comparative example, and the permanent magnet and the hysteresis material are in contact during the paper feeding operation.

From these results, the torque was stable even after 2,000,000 paper-passing operations were performed in this example. According to this embodiment, since the diameters of the first and second sliding portions are larger than the outer diameter of the permanent magnet of the first rotating body, it is possible to prevent the deviation of the gap. Further, in this example, the permanent magnet and the hysteresis material did not come into contact with each other even after 2,000,000 paper-passing operations. In other words, it was found that the present example is excellent in durability and can stabilize torque. In this example, the gap could be made smaller than in the comparative example. Since the output torque increases as the gap becomes smaller, it was found that this embodiment can improve the torque.

The embodiments disclosed this time are illustrative in all respects and should be considered not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and all meanings and scopes equivalent to the scope of the claims are intended.

Reference Signs List 1, 1A torque limiter 10, 10A first rotating body 11, 11A rotating shaft 12 permanent magnet 13, 13A, 15A first sliding portion 20, 20A second rotating body 21, 21A housing 22 hysteresis Material 23, 23A, 25A Second sliding portion 24 Lid portion 24a, 24b End surface 30 First shaft portion 31 First portion 32 Second portion 33 Third portion 34 Fourth portion 35A Second 1 convex portion 36A concave portion 37A second convex portion 40 second shaft portion 41 first side wall portion 42 outer peripheral portion 43 first outer peripheral portion 44 second outer peripheral portion 45A second side wall portion 46A second second outer wall portion, 47A third outer peripheral portion, 48A fourth outer peripheral portion, 49A fifth outer peripheral portion, 100 torque limiter, 101 friction roller, 102 feeding roller, 103 paper, 104 shaft, 200 torque limiter, 210 first rotating body, 211 rotating shaft, 212 permanent magnet, 220 second rotating body, 221 housing, 222 hysteresis material, 223 lid, 231, 232 sliding portion.

Claims (3)

a rotating shaft; a first rotating body including one of a permanent magnet and a hysteresis material attached to the outer peripheral surface of the rotating shaft;
a housing that is relatively rotatable coaxially with the rotating shaft; and the permanent magnet or the hysteresis material attached to the inner peripheral surface of the housing and facing the permanent magnet or the hysteresis material across a gap. and a second rotating body including the other,
The rotation shaft of the first rotor and the housing of the second rotor have sliding portions that slide in the circumferential direction,
The diameter of the sliding portion is the same as or larger than the outer diameter of one of the permanent magnets or the hysteresis material of the first rotor, and the other of the permanent magnets or the hysteresis material of the second rotor. A torque limiter , characterized in that it is equal to or smaller than the inner diameter of the 2. The torque limiter according to claim 1 , wherein the radial dimension of the gap between said permanent magnet and said hysteresis material is 0.2 mm or less. 3. The torque limiter according to claim 1 , wherein a plurality of said sliding portions are provided so as to sandwich either the permanent magnet or the hysteresis material of said first rotating body from both sides in the rotation axis direction.

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