JPH0620945U - Torque limiter - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a torque limiter that can obtain a sufficient torque even if it is downsized. A first rotating shaft 1, a permanent magnet 3 fixed to the first rotating shaft 1, a semi-hard magnet 4 attracted to the permanent magnet 3 with a gap, and a semi-hard magnet 4 The combined second rotating shaft 2 is provided, and the permanent magnet 3 is composed of a rare earth magnet. The permanent magnet 3 is covered with a viscous liquid material. The first rotating shaft is made of polyamide resin and the second rotating shaft is made of polyolefin resin. [Effect] Sufficient torque can be obtained even with a small size. The sliding parts are less worn and rotational runout is less likely to occur. It is possible to prevent a decrease in torque due to rust. It is less likely that the permanent magnet will come off or seizure between the first rotating shaft and the second rotating shaft will occur.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a torque limiter, and more particularly to a torque limiter that uses hysteresis torque to generate high torque.

[0002]

[Prior art]

 Known torque limiters utilizing hysteresis torque are disclosed in, for example, Japanese Utility Model Publication No. 59-42535 and Japanese Utility Model Publication No. 61-193937. In such a conventional torque limiter, a ferrite magnet is used as a permanent magnet.

[0003]

[Problems to be solved by the device]

 In conventional torque limiters, ferrite magnets are used as permanent magnets, but there is a limit to miniaturization if the required torque is obtained due to the magnetic characteristics of ferrite magnets. For example, the size of a torque limiter used for a paper feed roller of a printer or the like has an outer diameter of 25 to 30 mm and a length of 30 to 60 mm, but there is a problem that the required torque cannot be obtained if the size is made smaller than this. In addition, since the ferrite magnet is manufactured by sintering, the dimensional accuracy is low, and there is a problem that rotational run-out easily occurs.

Therefore, an object of the present invention is to provide a torque limiter that can obtain a sufficient torque even when it is downsized and that is less likely to cause rotational runout.

[0005]

[Means for Solving the Problems]

 The torque limiter of the present invention relates to a first rotating shaft, a permanent magnet fixed to the first rotating shaft, a semi-hard magnet attracted to the permanent magnet with a gap, and a semi-hard magnet. A second rotating shaft combined with the permanent magnet, wherein the torque limiter between the permanent magnet and the semi-hard magnet transmits the rotation between the first rotating shaft and the second rotating shaft. Is a rare earth magnet. Examples of rare earth magnets include Nd-Fe-B based magnets, Sm-Fe-N based magnets and Sm-Co based magnets.

In the above structure, it is preferable that the permanent magnet is covered with a viscous liquid material. Examples of viscous liquids include liquid polymers such as silicone oil, glycerin, mineral oil and hydraulic oil.

In the above structure, it is preferable that the first rotating shaft is made of polyamide resin and the second rotating shaft is made of high molecular polyolefin resin. This polyolefin resin is a generic term for homopolymers of olefins such as ethylene, propylene and butene, or copolymers with different polyolefins, and typical examples thereof include polyethylene resin, polypropylene resin, polybutane resin and the like. As the polyamide resin, there are 6 nylon, 6,6 nylon, 12 nylon and the like.

[0008]

[Action]

 In the torque limiter of this invention, a rare earth magnet is used as the permanent magnet.However, since the rare earth magnet has stronger magnetic characteristics than the ferrite magnet, even if it is made smaller than the case where the ferrite magnet is used, a sufficient torque can be obtained. Can be obtained. In addition, since the rare earth magnet is manufactured by pressing, the dimensional accuracy is high, and rotational runout is less likely to occur.

By the way, although rust is not a problem in ferrite magnets, rust is likely to occur in rare earth magnets, and deterioration of magnetic force characteristics due to rust, that is, reduction of torque becomes a problem. If the rare-earth magnet is coated with a viscous liquid material there, rusting can be prevented, and torque reduction due to rusting can be prevented. If the gap between the rare earth magnet (permanent magnet) and the semi-hard magnet is filled with the viscous liquid, the viscosity can improve the torque.

Further, conventionally, the first rotary shaft and the second rotary shaft are made of, for example, polyacetal resin, but when continuously rotated under high torque, the permanent magnet comes off due to heat generation of the first rotary shaft, or the first rotary shaft. However, if the first rotary shaft is made of a polyimide resin and the second rotary shaft is made of a polyolefin resin, the first rotary shaft has excellent adhesiveness and heat resistance. Since the permanent magnet is unlikely to come off, the sliding property with the second rotary shaft is excellent, so that abrasion and seizure are less likely to occur.

[0011]

【Example】

 The present invention will be further described below with reference to the embodiments shown in the drawings. However, this does not limit the invention. FIG. 1 is an end view of a paper feed roller using a torque limiter 10 according to an embodiment of the present invention. In the torque limiter 10, the first rotating shaft 1 has a drum shape and is made of polyamide resin. In addition to the polyamide resin, polyphenylene sulfide resin (PPS), polyphenylene oxide resin (PPO) or the like may be used. A metal shaft 1a is fitted in the center of the first rotating shaft 1, and a cylindrical permanent magnet 3 is fixed to the outer peripheral surface by an adhesive.

The permanent magnet 3 is composed of Nd-Fe-B based magnet powder (MQ powder; manufactured by General Motors, Inc.) and a thermosetting resin (for example, epoxy resin or phenol resin), which is a predetermined bond magnet powder. After being placed in a mold, compression molded, heated and cured, the surface was coated with resin for rust prevention, and the outer circumference was magnetized using a magnetizing yoke. In addition to the Nd-Fe-B based magnet, an Sm-Fe-N based magnet, an Sm-Co based magnet, or the like may be used.

The second rotating shaft 2 has a sleeve shape and is made of a polyolefin resin. A cylindrical semi-hard magnet 4 is fixed to the inner peripheral surface of the second rotating shaft 2 by a shrinkage fitting method, and a lid 2a is attached after the first rotating shaft 1 is inserted. . A rubber roller G is fitted on the outer peripheral surface. The semi-hard magnet 4 is made of a Fe-Cr-Co based magnetic material. In order to effectively use the magnetic force of the permanent magnet 3, it is preferable to make the both ends of the semi-hard magnet 4 longer than the both ends of the permanent magnet 3.

The first rotating shaft 1 and the second rotating shaft 2 are positioned in the radial direction by abutting on the sliding portions 6a and 6b, and are positioned in the axial direction by abutting via the washers 7a and 7b. Has been done. The washers 7a and 7b are disc-shaped films made of polyimide resin. Note that polyamide resin, unsaturated polyester resin, polyethylene resin, etc. may be used. When the first rotary shaft 1 and the second rotary shaft 2 are positioned, a predetermined gap is formed between the permanent magnet 3 and the semi-hard magnet 4. Silicon oil 8 is filled in this gap. The silicone oil 8 also covers the end surface of the permanent magnet 3 and prevents the permanent magnet 3 from rusting together with the resin coating. In addition to preventing rusting, the silicone oil 4 applies viscous torque, which also contributes to the improvement of torque. Instead of the silicone oil 4, glycerin, mineral oil, hydraulic oil, etc. may be used.

FIG. 2 is a comparison table of example data of the present invention and conventional example data using an anisotropic ferrite magnet as the permanent magnet 3. According to the embodiment data of this invention, the torque is 1.48 to 1.80 times that of the conventional data. The size of the torque limiter thus obtained has an outer diameter of 20 mm and a length of 25 mm, but the torque required for the paper feed roller is obtained.

FIG. 3 is a comparison table of wear resistance test results of materials used for the first rotary shaft 1 and the second rotary shaft 2. The lid 2a is made of the same material as the second rotating shaft 2. POM is a polyacetal resin and OL-10 is an oil-containing polyacetal resin. Use of 6,6 nylon for the first rotary shaft 1 and Polyfine (trade name; manufactured by Tokuyama Soda Co., Ltd .; polypropylene resin) for the second rotary shaft 2 (and lid 2a) has the best wear resistance. You can see that

[0017]

[Effect of device]

 Since the torque limiter of the present invention has the above-mentioned configuration, it is small in size and high in torque can be obtained. Also, rotational runout is less likely to occur. In addition, the viscous liquid substance can prevent a decrease in torque due to rust of the rare earth magnet (permanent magnet). Further, the viscosity can improve the torque. Further, by making the first rotating shaft made of polyamide resin and the second rotating shaft made of polyolefin resin, the permanent magnet is less likely to come off, seize, and wear.

[Submission date] February 15, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

In the above structure, it is preferable that the permanent magnet is covered with a viscous liquid material. The viscous liquid material, liquid material polymers, such as silicone over N'oiru, glycerin, mineral oil, and the like hydraulic oil.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007] In the above structure, the first rotation shaft is made of a polyamide resin, to the second rotation shaft made of Po Li olefin resin. The polyolefin resin is ethylene emissions, propylene, a general term of a copolymer of an olefin homopolymer or different polyolefin emissions of butene as a typical example, polyethylene resins, polypropylene resins, polybutylene te down resin are mentioned To be Polyamide resins include 6 nylon, 6,6 nylon and 12 nylon.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The first rotating shaft 1 and the second rotating shaft 2 are positioned in the radial direction by abutting on the sliding portions 6a, 6b, and are positioned in the axial direction by abutting via the washers 7a, 7b. Has been done. The washers 7a and 7b are disc-shaped films made of polyimide resin. Note that polyamide resin, unsaturated polyester resin, polyethylene resin, etc. may be used. When the first rotary shaft 1 and the second rotary shaft 2 are positioned, a predetermined gap is formed between the permanent magnet 3 and the semi-hard magnet 4. This gap, silicone over N'oiru 8 is filled. Silicone over N'oiru 8, the end face of the permanent magnet 3 also covers, and prevents rusting of the permanent magnet 3 with the resin coating. Silicone over N'oiru 8, outside to prevent rusting, for applying viscous torque, which contributes to the improvement of the torque. Instead of the silicone over N'oiru 8, glycerin, mineral oil, may be used hydraulic oil.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

FIG. 3 is a comparison table of wear resistance test results of materials used for the first rotary shaft 1 and the second rotary shaft 2. The lid 2a is made of the same material as the second rotating shaft 2. POM is a polyacetal resin, and CF-POM is a carbon fiber-containing polyacetal resin (manufactured by Polyplastics Co., Ltd.). Further, OL-1 0 is a oil-impregnated polyacetal resin (manufactured by Polyplastics Co., Ltd.). Using 6,6 nylon first rotary shaft 1, the second rotary shaft 2 (and the lid 2a) in polypropylene resin (trade name Poly Fine; manufactured by Tokuyama Soda Co., Ltd.) most wear resistance to use It turns out that it is excellent.

[Brief description of drawings]

FIG. 1 is a sectional view of a sheet feeding roller using a torque limiter according to an embodiment of the present invention.

FIG. 2 is a comparison chart of the example data of the present invention and the conventional example data.

FIG. 3 is a comparative chart of wear resistance test results according to materials used for the first rotating shaft and the second rotating shaft.

[Explanation of symbols]

 10 Torque limiter 1 1st rotating shaft 2 2nd rotating shaft 2a Lid 3 Permanent magnet 4 Semi-hard magnet 8 Silicon oil

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[Procedure amendment]

[Submission date] February 15, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

3. A torque limiter as claimed in claim 1 or claim 2, the first rotating shaft is made of a polyamide resin, a torque limiter, characterized in that the second rotary shaft is made of port re olefin resin. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 15, 1993

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Reference Numerals] 10 torque limiter 1 first rotary shaft 2 second rotary shaft 2a lid 3 permanent magnet 4 semirigid magnet 8 silicone over N'oiru

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure Amendment 8]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (3)

[Scope of utility model registration request] 1. A first rotary shaft, a permanent magnet fixed to the first rotary shaft, a semi-hard magnet attracted with a gap to the permanent magnet, and a second semi-hard magnet engaged with the semi-hard magnet. In a torque limiter having a rotating shaft and transmitting rotation between the first rotating shaft and the second rotating shaft by a hysteresis torque between the permanent magnet and the semi-hard magnet, the permanent magnet is a rare earth magnet. A torque limiter characterized in that 2. The torque limiter according to claim 1, wherein the permanent magnet is covered with a viscous liquid material. 3. The torque limiter according to claim 1, wherein the first rotating shaft is made of polyamide resin and the second rotating shaft is made of high molecular polyolefin resin.