JP2885663B2 - Torque limiter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter for transmitting a torque by a hysteresis torque generated between a permanent magnet and a semi-hard magnetic material.

[0002]

2. Description of the Related Art A torque limiter utilizing a hysteresis torque is used in a paper feeder of a copying machine, a printer or the like.

For example, FIGS. 7 and 8 show a double feed prevention mechanism of a sheet feeding device.
2) is pressed against the feed roller (33) with a predetermined pressure. The friction roller (32) has a torque limiter (3).
A constant torque (T) is always given in the direction of returning the paper (35) via 4). Then, the feed roller (3
3) and two or more sheets (3) between the friction roller (32).
When (5) is guided, the second and subsequent sheets (35) are separated from the first sheet and returned in the direction opposite to the sheet traveling direction (FIG. 7). However, when the feed roller (33) is in direct contact with the friction roller (32) or in contact with one sheet of paper, the friction roller (32) removes the sheet together with the feed roller (33). It turns around in the feeding direction (Fig. 8). Therefore, in order to reliably feed out the papers (35) one by one, the rotational torque (T) in the reverse direction given to the friction roller (32) by the torque limiter (34) increases the friction between the papers (35). It must be greater than the force but less than the rotational torque of the feed roller (33). And yet, the torque limiter (3
4) must always maintain a constant and stable torque (T).

Conventionally, a torque limiter using a hysteresis torque for a paper feeder as shown in FIG. 9 has been used. That is, two rotating bodies (36), (3) made of synthetic resin and relatively slidably rotatable coaxially.
7), a cylindrical permanent magnet (38) is fixed to one rotating body (36), and a cylindrical semi-rigid opposed to the permanent magnet (38) with a gap to the other rotating body (37). A torque limiter (34) having a structure in which a magnetic body (39) is fixed and a torque is transmitted between the two rotating bodies by a hysteresis torque generated between the permanent magnet (38) and the semi-hard magnetic body (39). This type of torque limiter (34)
The two rotating bodies (36) and (37) come into contact only at the sliding parts (40) and (41), and the permanent magnet (38) and the semi-hard magnetic body (39) that generate torque are non-contact. Contact. For this reason, the permanent magnet (38) and the semi-hard magnetic body (39) do not wear, and can transmit a stable torque for a long period of time.

In the conventional torque limiter (34),
The rotating body (3) to which the cylindrical permanent magnet (38) is fixed
As 6), a rotating body (36) made of a synthetic resin such as a polyacetal resin or a polyamide resin was used, and a cylindrical permanent magnet (38) was adhered to the outer periphery thereof. This is because these synthetic resins are excellent in slidability of the sliding portions (40) and (41).

[0006]

However, high torque,
When used under severe conditions such as high-speed rotation, the conventional torque limiter (34) cannot maintain the adhesion between the rotating body (36) and the permanent magnet (38), and the torque limiter (3)
During use of 4), the permanent magnet (38) falls off from the rotating body (36), or slips at the bonding surface between the permanent magnet (38) and the rotating body (36), thereby functioning as a torque limiter. There was a problem that it would not work.

Further, in the conventional torque limiter (34), when the permanent magnet (38) generates heat due to eddy current during use, the rotating body (3) to which the permanent magnet (38) is fixed by the heat.
6) expands and the permanent magnet (3
8) was broken. In contrast,
It is conceivable to increase the adhesive clearance between the rotating body (36) and the permanent magnet (38) to absorb the expansion of the rotating body (36).
This causes a problem that the surface of the permanent magnet (38) oscillates greatly and the torque value becomes unstable.

To solve these problems, Japanese Patent Application Laid-Open No.
No. 41 proposes that the rotating body is formed of a metal material having excellent dimensional stability and adhesiveness to a permanent magnet. By forming the rotating body from a metal material in this way, a certain effect could be obtained with respect to poor adhesion between the permanent magnet and the rotating body and cracking of the permanent magnet. However, considering the relative motion of the two rotating bodies (36) and (37) in a state where the torque limiter (34) is actually used in the sheet feeding device, the two rotating bodies (36) and (37) It can be seen that the pause state (the state of FIG. 7) and the rotation state (the state of FIG. 8) are frequently repeated. Then, it has been found that under such a use condition that the pause and the rotation are frequently repeated, the torque value becomes unstable in the torque limiter in which the rotating body is formed of a metal material.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and to realize the use of a permanent magnet and a rotating magnet even under severe conditions such as temperature change, high torque, high speed rotation, and frequent repetition of pause and rotation. It is an object of the present invention to provide a torque limiter which does not cause poor adhesion to a body or cracks of a permanent magnet, has excellent slidability of a sliding portion, and can transmit a stable torque.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present inventor has disclosed in Japanese Patent Application Laid-Open No. 6-22134.
The instability of the torque value of the torque limiter described in Japanese Unexamined Patent Publication No. 1 under the use condition in which the pause and the rotation are frequently repeated is considered to be due to the large static friction of the sliding portion. The present invention has been accomplished as a result of repeated studies on suitable materials for the sliding portion and the sliding portion. The present invention has the following contents to solve the above problems.

[0011] First of all, that this invention is applied, the center
A first rotating body in which a shaft is inserted into the hole, and the first rotating body;
A second rotating body that is relatively slidable and rotatable coaxially with the body;
One of the first rotating body and the second rotating body is fixed to one of the rotating bodies.
Attached to the cylindrical permanent magnet and the cylindrical half
It consists of a hard magnetic material, prior to SL and the inner peripheral surface or outer peripheral surface of the outer peripheral surface or inner peripheral surface of the permanent magnet and the semi-hard magnetic material against direction with a gap, between the permanent magnet and the semi-hard magnetic material The first rotating body and the second
This is a type of torque limiter that transmits torque between two rotating bodies .

Here, the shape, size and positional relationship of the two rotating bodies are not particularly limited as long as they can be installed so as to be relatively slidable and rotatable coaxially. On the other hand, it is essential that the permanent magnet and the semi-hard magnetic body are cylindrical bodies having different diameters. The permanent magnet and the semi-hard magnetic body are coaxially placed in a non-contact manner, with one of the insides being the inside and the other being the outside, with the peripheral surfaces facing each other. Preferred embodiments of this type of torque limiter include the following (A) and (B).

(A) A permanent magnet is provided on the outer peripheral surface of the first rotating body.
The semi-hard magnetic material is fixed to the inner peripheral surface of the second rotating body,
The outer peripheral surface of the permanent magnet faces the inner peripheral surface of the semi-hard magnetic material
Aspect it is.

(B) Semi-hard magnetism on the outer peripheral surface of the first rotating body
The body is fixed, and the permanent magnet is fixed to the inner peripheral surface of the second rotating body,
The outer peripheral surface of the semi-hard magnetic body and the inner peripheral surface of the permanent magnet face
Aspect it is.

In the case (A), a hysteresis torque is generated by the relative rotation between the inner permanent magnet and the outer semi-hard magnetic material. Conversely, in the case of (B), a hysteresis torque is generated by the relative rotation between the inner semi-hard magnetic body and the outer permanent magnet.

In addition to the above (A) and (B), for example, each rotating body has a disk shape, and a cylindrical permanent magnet or a cylindrical semi-hard magnetic material is fixed on its surface from the end. Such a mode may be adopted.

According to the present invention, in the torque limiter as described above, the rotating body to which the permanent magnet is fixed is such that at least the permanent magnet fixing portion is made of a metal material and at least the sliding portion is made of a synthetic resin material. The rotating body to which the semi-rigid magnetic body is fixed is characterized in that at least the sliding portion is made of a synthetic resin material.

As described above, in the torque limiter according to the present invention, the permanent magnet fixing portion of the rotating body to which the permanent magnet is fixed is formed of a metal material. Since the metal material is superior in the adhesiveness to the permanent magnet and the dimensional stability as compared with the synthetic resin material, the metal material can firmly adhere the permanent magnet to the rotating body, and is caused by the thermal expansion of the rotating body. Cracking of the permanent magnet can be prevented. Since both sliding parts of the rotating body to which the permanent magnet is fixed and the rotating body to which the semi-hard magnetic material are fixed are both formed of a synthetic resin material, the frictional resistance of the sliding parts, especially the static friction, Can be reduced, and excellent slidability can be obtained.

Next, each component constituting the torque limiter according to the present invention will be described in more detail.

[Permanent Magnet] Ferrite magnets and rare earth magnets (both including sintered magnets and resin magnets) are used as permanent magnets. Rare earth magnets are used from the viewpoint of reducing the size of the torque limiter and increasing the torque. It is desirable to use. Nd-Fe-B based magnets, Sm-Fe
-N-based magnets, Sm-Co-based magnets, and the like.

[Rotating body to which permanent magnet is fixed] The most important component of the present invention is the rotating body to which the permanent magnet is fixed. As described above, the rotating body to which the permanent magnet is fixed is required to have at least the permanent magnet fixing portion made of a metal material and at least the sliding portion made of a synthetic resin material. It is preferable that the rotating body to which the permanent magnet is fixed is configured by one of the following.

A structure in which a rotating body main body including a sliding portion is made of a synthetic resin material, and a permanent magnet fixing portion is made of a metal material.

In this case, the main body of the rotating body is made of a synthetic resin material, but the permanent magnet fixing portion is made of a metal material. The dimensions of the fixed portion are maintained, and cracking of the permanent magnet can be prevented. As described above, the metal material provides excellent adhesiveness to the permanent magnet, and the synthetic resin material provides excellent slidability.

More specifically, such a rotating body includes the following (a) to (c).

(A) A rotating body made of a synthetic resin material in which a metal cylindrical body is press-fitted into a portion serving as a permanent magnet fixing portion. This case is preferable in that a special rotating body can be easily obtained by a press-fitting jig without special skill.

(B) A rotary body made of a synthetic resin material in which a metal material is sprayed on a portion to be a permanent magnet fixing portion. This case is preferable in that a metal coating can be formed at an arbitrary position on the rotating body.

(C) A rotor body made of a synthetic resin material and a permanent magnet fixing portion made of a metal material are integrally formed by injection molding of the rotor body. in this case,
This is preferable because the press-fitting step shown in (a) is unnecessary and a strong connection between the rotating body and the metal material can be obtained.

A structure in which a rotating body main body including a permanent magnet fixing portion is made of a metal material, and a sliding portion is made of a synthetic resin material.

In this case, since the rotating body including the permanent magnet fixing portion is made of a metal material, it has excellent adhesion to the permanent magnet and dimensional stability. Further, since the sliding part is made of a synthetic resin material, the sliding property is excellent. In addition, since the body of the rotating body is made of a metal material, hysteresis heat and frictional heat generated during running of the torque limiter can be released to the outside through a metal material having good heat conductivity, and the temperature rise of the torque limiter can be suppressed. It also has the advantage. For this reason, it is possible to prevent a decrease in the magnetic force of the permanent magnet and a change in the coefficient of friction of the sliding portion due to the temperature rise.

More specifically, such a rotating body includes the following (d) to (f).

(D) A cylindrical body or an annular body made of a synthetic resin is press-fitted into a portion serving as a sliding portion of a rotating body main body made of a metal material. This case is preferable in that no special skill is required and the target rotating body can be easily obtained by the press-fitting jig.

(E) A rotating body made of a metal material, in which a synthetic resin material is applied to a portion serving as a sliding portion. In this case, a thin synthetic resin layer can be formed. It is preferable to reduce the thickness of the synthetic resin layer because it is possible to maximize the dimensional stability and the heat radiation effect of the metal material forming the rotator body.

(F) A rotating body made of a metal material and a sliding portion made of a synthetic resin material are integrally formed by injection molding of the sliding portion. This case is preferable in that the special steps shown in (d) and (e) are not required, and a strong connection between the rotating body main body and the synthetic resin material can be obtained.

As the synthetic resin material, a material excellent in slidability, heat resistance, dimensional stability and strength is suitable. Specifically, polyacetal resin, polyamide resin, polyolefin resin, polyimide resin, polyester resin, fluorine resin, polyphenylene sulfide resin, polyphenylene oxide resin, polycarbonate resin, ABS resin, polyetherimide resin, liquid crystal polymer, phenol resin, epoxy resin And the like. Among them, polyacetal resins, polyolefin resins and fluororesins are particularly preferred. The synthetic resin material may be mixed with a filler such as oil, potassium titanate whisker, graphite, fluororesin powder or the like in order to improve the slidability.

The metal material may be a magnetic metal or a non-magnetic metal. Specific examples include an aluminum alloy, a zinc alloy, stainless steel, a lead alloy, and a copper alloy.

[Semi-hard magnetic material] As the semi-hard magnetic material,
High residual magnetic flux density and a certain degree (10-10000e)
Although a metal material having a coercive force of and having a square hysteresis is used, from the viewpoint of reducing the size and increasing the torque of the torque limiter, it is preferable to use an Fe-Co alloy, an Fe-Cr-Co alloy, or the like. preferable. The semi-rigid magnetic material is conventionally used in a cylindrical shape by curling a plate-like material.However, in the torque limiter according to the present invention, a seamless material having no seams is used. Is preferred. As described above, by using a seamless cylindrical semi-hard magnetic material having no seam, it is possible to prevent disturbance of lines of magnetic force and to suppress minute fluctuations in torque. In addition, a seamless cylindrical semi-hard magnetic material having no seams is also excellent in roundness and cylindricity, so that the gap between the permanent magnet and the semi-hard magnetic material can be set small, and the torque limiter can be set. This is also advantageous from the viewpoint of reducing the size and increasing the torque.

[Rotating Body for Fixing Semi-Hard Magnetic Body] In the rotating body for fixing the semi-hard magnetic body, it is essential that at least the sliding portion is made of a synthetic resin material. That is, the entire portion including the sliding portion may be formed of a synthetic resin material, or portions other than the sliding portion may be formed of another material. As the synthetic resin material forming the rotating body, those described above as the synthetic resin material suitable for the rotating body for fixing the permanent magnet can be directly applied. Further, when a portion other than the sliding portion of the rotating body is formed of a material other than the synthetic resin, the material of the portion is not particularly limited.

[Others] A liquid oil can be added as a lubricating oil to the sliding portion between the two rotating bodies, if necessary, in order to improve sliding characteristics and prevent wear. Examples of the liquid oil include synthetic oils such as silicone oil, naphthenic or paraffinic mineral oils, and hydraulic oils. further,
The mixture of the liquid oil and the solid lubricant may be added to the sliding portion between the two rotating bodies. As solid lubricants,
Powdered fluororesin, molybdenum disulfide, graphite, tungsten disulfide, boron nitride, graphite fluoride, melamine cyanurate resin, polyethylene resin, polypropylene resin, silicone resin, metal soap and the like can be used.

Further, for the purpose of preventing rusting of the permanent magnet and the semi-hard magnetic material and improving the rotational torque, a synthetic oil such as silicone oil, naphthenic or paraffin-based material is provided between the permanent magnet and the semi-hard magnetic material. Viscous liquids such as mineral oil and hydraulic oil may be filled.

[0040]

Next, an embodiment of the present invention will be described.

[Embodiment 1] FIG. 1 is a sectional view when a torque limiter (1) according to Embodiment 1 of the present invention is used for a friction roller (2) for feeding paper. In FIG. 1, a torque limiter (1) is composed of a first rotating body (4) having a cylindrical permanent magnet (3) fixed to an outer peripheral surface, and a second rotating body (5) having a cylindrical semi-hard magnetic body (5) fixed to an inner peripheral surface. It consists of two rotating bodies (6),
Further, the second rotating body (6) includes a bottomed cylindrical body (6a) having a shaft through hole (7) at the bottom center and a lid (6b) having a bearing hole at the center. . The torque limiter (1) is assembled by inserting the first rotating body (4) into the bottomed cylindrical body (6a) of the second rotating body (6), and then attaching the lid (6b). . First
The rotating body (4) is connected to a drive mechanism (not shown) through a metal shaft (8). Also, the second rotating body (6)
Has a notch (9) formed in the bottom in the diameter direction,
The notch (9) is engaged with the protrusion on the end face of the rubber roller (2).

Here, the cylindrical permanent magnet (3) and the cylindrical semi-hard magnetic body (5) face each other with a predetermined gap. In addition, the first rotating body (4) and the second rotating body (6) are installed coaxially, and positioning in the radial direction and the axial direction can be performed by abutment at the sliding portions (10) and (11). It is relatively slidable and rotatable coaxially. (12) is a positioning flange,
The positioning of the permanent magnet (3) fixed to the first rotating body (4) and the positioning of the second rotating body (6) with respect to the first rotating body (4) are performed by the flange (12). Here, when a rotational force is applied to the first rotating body (4) through the metal shaft (8), the second rotating body is rotated by the hysteresis torque generated between the permanent magnet (3) and the semi-hard magnetic body (5). A constant torque is transmitted to the body (6).

FIG. 2 is a sectional view of the first rotating body (4) in FIG. In the first rotating body (4) shown in FIG. 2, the rotating body main body (13) including the permanent magnet fixing portion is made of a metal material, and the sliding portions (10a) and (11a) are made of a synthetic resin material. The first rotating body (4) is obtained by press-fitting polyacetal resin cylindrical bodies (10a) and (11a) into a portion serving as a sliding portion of a rotating body main body (13) made of stainless steel. The polyacetal resin is an oil-containing polyacetal resin mixed with oil.

A cylindrical permanent magnet (3) is fixed to the outer peripheral surface of the first rotating body (4) with an adhesive. This permanent magnet (3) is a Nd-Fe-B resin magnet, and Nd-F
A resin magnet powder composed of an EB-based magnetic powder and an epoxy resin is charged into a predetermined mold, compression-molded, cured by heating, and further coated with a resin for rust prevention, and then magnetized. The outer periphery is multipolar magnetized by using a yoke.

The second rotating body (6) is made of polyacetal resin. This polyacetal resin is the oil-containing polyacetal resin described above. A cylindrical semi-hard magnetic body (5) is fixed to the inner peripheral surface of the second rotating body (6) by press-fitting. This semi-hard magnetic material (5) is made of Fe-Cr
-Co-based alloy. This semi-hard magnetic body (5) is a seamless cylindrical body without any seams.

The sliding parts (10a) and (11a)
Instead of press-fitting the cylindrical body, it may be formed by coating a synthetic resin material. In addition, the sliding part (1
0a) and (11a) by injection molding.
It may be formed integrally with 3).

Further, in this embodiment, the first rotating body (4) may be replaced with, for example, the one shown in FIG.

In the first rotating body (14) shown in FIG. 3, the rotating body (17) including the sliding parts (15a) and (16a) is made of a synthetic resin material, and the permanent magnet fixing part (18) is made of metal. Made of material. The first rotating body (14) is made of a metal cylindrical body (1) by injection molding of a rotating body main body (17).
8) and one in a mold. The rotating body (17) is made of the oil-containing polyacetal resin described above,
The cylindrical body (18) is made of stainless steel. In addition, the cylindrical body (18) is a rotating body main body (1
It may be one that has been pressed into the outer peripheral surface of 7) later. Further, a metal material may be sprayed at a predetermined position on the outer periphery of the rotating body (17).

Embodiment 2 FIG. 4 shows Embodiment 2 of the present invention.
FIG. 7 is a cross-sectional view when a torque limiter (19) is used for a friction roller (2) for feeding paper. In this example,
This embodiment is different from the first embodiment in that a semi-hard magnetic body (21) is fixed to the first rotating body (20) and a permanent magnet (23) is fixed to the second rotating body (22). That is, in FIG. 4, a torque limiter (19) has a first rotating body (20) having a cylindrical semi-hard magnetic body (21) fixed to the outer peripheral surface, and a cylindrical permanent magnet (23) fixed to the inner peripheral surface. Second rotating body (2
2), and the second rotating body (22)
A bottomed cylindrical body (22a) having a shaft through hole (24) at the bottom center, and a lid (2) having a bearing hole at the center.
2b). This torque limiter (19)
Is assembled by inserting the first rotating body (20) into the bottomed cylindrical body (22a) of the second rotating body (22), and then attaching the lid (22b). The first rotating body (20) is connected to a drive mechanism (not shown) through a metal shaft (8). Also, the second rotating body (22)
A notch (25) is formed in the bottom of the rubber roller (2) in the diametric direction, and the notch (25) is engaged with the projection on the end face of the rubber roller (2).

Here, the cylindrical permanent magnet (23) and the cylindrical semi-hard magnetic body (21) are opposed to each other with a predetermined gap, and the first rotating body (20) and the second rotating body (22). Are mounted coaxially, and the sliding parts (26), (27)
The positioning in the radial direction and the axial direction is performed by the abutment in the above, the relative sliding rotation is possible on the same axis, and the torque transmission mechanism and the like are the same as in the first embodiment.

The first rotating body (20) is made of the oil-containing polyacetal resin. A cylindrical semi-hard magnetic body (21) is press-fitted on the outer peripheral surface of the first rotating body (20). This semi-hard magnetic body (21) is made of an Fe-Cr-Co alloy. The semi-hard magnetic body (21) is a seamless cylindrical body without any seams.

On the other hand, on the inner peripheral surface of the second rotating body (22),
A cylindrical permanent magnet (23) is fixed by an adhesive. This permanent magnet (23) is a Nd-Fe-B resin magnet. A resin magnet powder composed of an Nd-Fe-B magnetic powder and an epoxy resin is charged into a predetermined mold, compression-molded, and heated. After hardening and further coating the surface with a resin for rust prevention, multipolar magnetization is performed on the inner circumference using a magnetization yoke.

FIG. 5 shows the second rotating body (22) in FIG.
FIG. In the second rotating body (22) shown in FIG. 5, the bottomed cylindrical body (22a) serving as the rotating body main body having the permanent magnet fixing portion is formed of stainless steel. A ring (27a) made of polyacetal resin is press-fitted into the bottom of the bottomed cylinder (22a) to form one sliding portion. Lid (2) including the other sliding portion (26a)
2b) is made of polyacetal resin. Ring (27
The polyacetal resin forming a) and the lid (22b) is the oil-containing polyacetal resin.

Further, in this embodiment, the second rotating body (22) may be replaced with, for example, the one shown in FIG.

A second rotating body (28) shown in FIG. 6 has a bottomed cylindrical body (28a) as a rotating body having one sliding portion (30a) and a lid having the other sliding portion (29a). Body (2
8b). Both the bottomed cylinder (28a) and the lid (28b) are made of the oil-containing polyacetal resin. On the other hand, the permanent magnet fixing portion (31) formed on the inner peripheral surface of the bottomed cylindrical body (28a) is made of a metal material. The permanent magnet fixing portion (31) is formed by press-fitting a stainless steel cylinder into the inner peripheral surface of the bottomed cylinder (28a). The integration of the bottomed cylindrical body (28a) and the permanent magnet fixing part (31) is not performed by press-fitting, but is performed by metal permanent magnet fixing part (31) at the time of injection molding of the bottomed cylindrical body (28a). And may be integrally formed in a mold.

[0056]

[Comparative test] The "endurance running test" and "heat cycle test" were performed on the torque limiters according to the above-mentioned Examples 1 and 2 as follows. In addition, the torque limiters of the following comparative examples 1 and 2 were used as comparative objects.

COMPARATIVE EXAMPLE 1 The first rotating body (4) was entirely made of the oil-containing polyacetal resin, and the other example was the same as in Example 1.
The same as above.

Comparative Example 2 The first rotary member (4) was entirely made of stainless steel, and the other conditions were the same as in Example 1.

Table 1 shows the structure of the main part of each torque limiter.

[0060]

[Table 1]

[Durability Running Test] For each torque limiter, while the second rotating body was forcibly stopped, only the first rotating body was rotated under the following conditions, and the torque transmitted to the second rotating body was measured. Running conditions : 1000 rpm × 120 ms → 637 rpm
× 720ms → 0rPm × 360ms cycle is 30
Repeated for 0 hours. Measurement method : The torque value was measured every minute for 30 minutes from the start of running, and was used as the initial value. In addition, 30 minutes before the end of traveling,
Similarly, the torque value was measured every minute.

The measurement results are also shown in Table 1. As can be seen from the results of the determination in Table 1, the torque limiter of Comparative Example 1 in which the permanent magnet was adhered to the rotating body made of polyacetal resin, the permanent magnet fell off the rotating body during the running test, and the measurement became impossible. . Further, in the torque limiter of Comparative Example 2 in which the permanent magnet was bonded to the rotating body made of stainless steel, the permanent magnet did not fall off, but the torque value after 300 hours had large dispersion and the torque was unstable. On the other hand, in the torque limiter of the embodiment, the permanent magnet did not fall off, there was no large change between the initial torque value and the torque value after 300 hours, and the torque value after 300 hours passed was extremely low. Was stable.

[Heat cycle test] The rotating body to which the permanent magnet of each torque limiter is fixed, that is, the first rotating body of the working example 1, the comparative examples 1 and 2, and the second rotating body of the embodiment 2. Was placed in a furnace, and the temperature of the furnace was changed under the following conditions to check for cracks in the permanent magnet. Temperature condition: -10 ° C × 2 hours → 23 ° C × 2 hours → 1
10 cycles of 00 ° C x 2 hours → 23 ° C x 2 hours
Repeated times. Table 1 also shows the measurement results.

[0064]

As described above in detail, the torque limiter according to the present invention has a structure in which the permanent magnet fixing portion of the rotating body on which the permanent magnet is fixed is formed of a metal material and the permanent magnet is fixed. Both the sliding part of the rotating body and the rotating body on which the semi-hard magnetic body is fixed are made of a synthetic resin material, so that the temperature change, high torque, high speed rotation, and even pause and rotation Even when used under severe conditions such as frequent repetitions, it does not cause poor adhesion between the permanent magnet and the rotating body or cracks in the permanent magnet, and has excellent sliding properties of the sliding part and stable torque for a long time. Can be transmitted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a torque limiter according to a first embodiment of the present invention is used for a friction roller for feeding paper.

FIG. 2 is a sectional view of a first rotating body used in the first embodiment of the present invention.

FIG. 3 is a sectional view showing another example of the first rotating body used in the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a state in which a torque limiter according to Embodiment 2 of the present invention is used for a friction roller for feeding paper.

FIG. 5 is a sectional view of a second rotating body used in Embodiment 2 of the present invention.

FIG. 6 is a cross-sectional view showing another example of the second rotating body used in Embodiment 2 of the present invention.

FIG. 7 is a diagram illustrating a double feed prevention mechanism of the sheet feeding device.

FIG. 8 is a diagram illustrating a double feed prevention mechanism of the sheet feeding device.

FIG. 9 is a cross-sectional view illustrating a state in which a conventional torque limiter is used for a friction roller for feeding paper.

[Description of Signs] 1,19 Torque limiter 2, Friction roller for feeding paper 3,23 Permanent magnet 4,14,20 First rotating body 5,21 Semi-hard magnetic body 6,22,28 Second rotating body 8 Shaft 10 , 11 Sliding parts 10a, 11a, 15a, 16a (of first rotating body)
Sliding part 13, 17 Rotating body main part (of first rotating body) 18 Permanent magnet fixing part 26, 27 Sliding part 26a, 27a, 29a, 30a (of second rotating body)
Sliding portions 22a, 28a Bottomed cylindrical body serving as rotating body (of second rotating body) 31 Permanent magnet fixing portion

Claims (11)

(57) [Claims] 1. A shaft for inserting a shaft into a center hole.
One rotator (4, 14, 20) and coaxial with the first rotator
The second rotating body (6, 22, 2
8) and the first rotating body and the second rotating body
A cylindrical permanent magnet (3, 23) fixed to one side;
A cylindrical semi-hard magnetic material (5, 21) fixed to the other
Rannahli, before Symbol outer or inner peripheral surface and the inner peripheral surface or outer peripheral surface of the front Symbol semi-hard magnetic material of the permanent magnet and is directed pairs with a gap, hysteresis torque generated between the permanent magnet and the semi-hard magnetic material in the torque limiter to transmit torque between said second rotary member and the first rotating member by, among the first rotary body and the second rotating body, the rotating body of the person which is fixed a permanent magnet, At least the permanent magnet fixing portion is made of a metal material, and at least the sliding portion is made of a synthetic resin material, and the rotating body on which the semi-hard magnetic material is fixed has at least the sliding portion made of a synthetic resin material. Torque limiter. 2. An outer peripheral surface of said first rotating body (4, 14).
The permanent magnet (3) is fixed and the second rotating body (6)
The semi-hard magnetic material (5) is fixed to the inner peripheral surface, and the permanent magnet
The outer peripheral surface of the stone and the inner peripheral surface of the semi-hard magnetic material face each other.
The torque limiter according to claim 1, wherein 3. An outer peripheral surface of the first rotating body (20).
The semi-hard magnetic body (21) is fixed, and the second rotating body (2) is fixed.
The permanent magnet (23) is fixed to the inner peripheral surface of (2, 28),
The outer peripheral surface of the semi-hard magnetic body and the inner peripheral surface of the permanent magnet
The torque limiter according to claim 1, wherein the torque limiter is opposed . 4. The first rotating body and the second rotating body.
Of out, the rotating body of the person which is fixed to the permanent magnet, the sliding portion
(15a, 16a, 29a, 30a)
The torque limiter according to any one of claims 1 to 3 , wherein (17 , 28a) is made of a synthetic resin material, and the permanent magnet fixing portion (18, 31) is made of a metal material. 5. The rotating body to which the permanent magnet is fixed,
The portion to be the permanent magnet fixing part of the rotating body is obtained by press-fitting a metal cylindrical body, the torque limiter according to claim 4. 6. The rotating body to which the permanent magnet is fixed,
The torque limiter according to claim 4 , wherein a metal material is thermally sprayed on a portion of the rotating body that is to be a permanent magnet fixing portion. 7. The rotating body of the person which is fixed to the permanent magnet,
A rotating body and the permanent magnet fixing portion by injection molding of the rotary body are integrally molded, the torque limiter according to claim 4. 8. The first rotating body and the second rotating body.
In the rotating body to which the permanent magnet is fixed, the rotating body (13, 22a) including the permanent magnet fixed portion is made of a metal material, and the sliding portion (10a, 11a, 26a, 27a) is used.
There made of a synthetic resin material, the torque limiter according to any one of claims 1 to 3. 9. Rotation of better to securing said permanent magnet,
A cylindrical body or the annular body made part of synthetic resin which is a sliding portion of the rotary body is obtained by press-fitting, the torque limiter according to claim 8. 10. A rotary body of the person which is fixed to the permanent magnet is obtained synthetic resin material is applied to the portion to be a sliding portion of the rotary body, the torque limiter according to claim 8. 11. Rotation of the person which is fixed to the permanent magnet is obtained by integrally molding by injection molding of the sliding portion and the rotary body and the sliding part, the torque limiter according to claim 8.