JPH0826513A - Torque limiter and paper feeder and business equipment using this torque limiter - Google Patents

Abstract

PURPOSE:To provide a uniform contact surface pressure by stabilizing a contact condition between a slide member and a friction member. CONSTITUTION:A tubular friction member 3 is fixedly mounted on a peripheral part of a rotary member 2. A tubular member 4 is externally fitted to outside the rotary member 2. A slide member 5 is applied to the friction member 3 through a window part 4a of the tubular member 4. A plurality of the slide members 5 is brought into press contact with a peripheral surface of the friction member 3 by a spring member 6. The slide member 5 is locked not in its radial direction movable but in its circumferential direction and axial line direction by the window part 4a. In this way, a contact condition between the slide member 5 and the friction member 3 is stabilized, to obtain a uniform contact surface pressure.

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 interrupting the transmission of torque when a torque of a certain value or more is applied, and a paper feeding device and office equipment using the torque limiter.

[0002]

2. Description of the Related Art Conventionally, in a power transmission mechanism of equipment, machinery, equipment, etc., when torque exceeding a certain value is applied, slippage occurs at a connecting portion using a friction member such as a friction plate. A torque limiter is known which has a function of preventing a force exceeding a permissible limit from acting on the power transmission mechanism and protecting the power transmission mechanism from an excessive load.

As a paper feeding device using such a torque limiter, there is known a roller separating system for separating the paper by reversing the separating roller and the feeding roller (for example, Japanese Patent Publication No. 4-11452). (See the official gazette). That is, in this roller separation type paper feeding device, in order to prevent double feeding of paper, slippage may occur at a connecting portion using a friction member such as a friction plate when torque of a certain value or more is applied. Therefore, a torque limiter is used to prevent a force exceeding an allowable limit from acting on the power transmission mechanism. Such a paper feeding device is used in office equipment such as a copying machine and a printer.

As the above-mentioned torque limiter, specifically, a torque limiter spring clutch (coil spring) having a function of protecting the power transmission mechanism from an excessive load is wound around a separation roller or the like made of a metal material such as iron. , That generates sliding torque while frictionally sliding the spring clutch and separation roller (metal material), or magnet powder is filled in the cylinder, and the sliding torque is generated by the flow resistance of the magnet powder. What is used is used.

[0005]

However, in the former case, it is necessary to interpose lubricating oil at the friction interface, and during use, the lubricating oil runs out and the sliding torque rises sharply.
In addition to the risk of the coil spring rusting and locking, very strict dimensional accuracy is required, and the torque is not stable during manufacturing. On the other hand, the latter is
Since the magnet powder is used, the cost is high, and the magnet powder is attracted to each other, which makes it difficult to handle. In addition, since all of them use a large amount of metal, the weight is considerably large, and it is difficult to reduce the weight of the entire device.

By the way, generally, when two members are brought into contact with each other and slid on each other, the mating members attack each other, and significant wear occurs on either or both of them, and abrasion powder is transferred or adhered to the surface of the member. The state changes and the friction coefficient during sliding changes. Therefore, in order to avoid such a change in the friction coefficient during sliding, a liquid lubricant is interposed at the friction interface to avoid sliding between solids, and the flow resistance against the shear strain rate generated in the liquid I try to generate power. Specifically, when metal members are brought into contact with each other and slide, a lubricant such as molybdenum disulfide or grease is interposed between them, and even when resin members are used, oil-containing resin is used. Then, the oil oozes to the friction interface.

However, even if these methods are used, there is a certain limit in avoiding a change in the friction coefficient during sliding. In other words, the friction coefficient becomes low by interposing a lubricant at the friction interface, so it is necessary to make the pressing force very large, but if the pressing force is made very large in this way, the mechanical strength that can withstand it will be increased. If it is necessary to select the material that has it, and if the lubricant runs out during use, the two members will be in contact with each other with a large pressing force, and the seizure phenomenon will occur in which the sliding torque will rapidly increase. Therefore, peripheral devices may be destroyed.

The present invention has been made in view of the above points, and a torque limiter that stabilizes the contact state between a sliding member and a friction member to obtain a uniform contact surface pressure, a paper feeding device and office equipment using the same. It is intended to provide.

[0009]

The invention according to claim 1 is
Assuming a torque limiter that cuts off the transmission of torque when a torque of a certain value or more is applied, the tubular first member into which the torque is input and the first member are coaxially externally fitted, A tubular second member having a plurality of windows, and the second member
A plurality of sliding members that are fitted into the window portion of the first member and contact the outer surface of the first member, and a plurality of sliding members that are mounted on the sliding members. And a spring member for generating a frictional force therebetween. In the invention according to claim 2, the sliding member is integrally provided with a friction member that comes into contact with the outer surface of the first member.

The invention according to claim 3 is premised on a torque limiter for interrupting the transmission of torque when a torque of a certain value or more acts, and a tubular first member to which torque is input, and the first member. A friction member fixedly attached to the outer peripheral portion of the first member, a tubular second member coaxially fitted to the first member and having a plurality of window portions, and a window of the second member. A plurality of sliding members that are fitted into the friction member and come into contact with the outer surface of the friction member, and a spring that is mounted on the sliding member and that generates a frictional force between the friction member and the sliding member. And a member.

In the invention according to claim 4, the sliding member is made of a thermoplastic resin, and the friction member is made of short fiber compounded rubber in which short fibers are exposed from the outer surface.

In order to obtain stable friction characteristics without using a lubricant such as molybdenum disulfide or grease, it is preferable to use a thermoplastic resin such as PP, ABS, POM, PPS or PES as the sliding member. desirable.

On the other hand, the friction member is a rubber mixed with short fibers, and the short fibers are exposed from the outer surface by polishing the surface after vulcanization. As the rubber used for the friction member, all rubbers such as natural rubber and synthetic rubber can be used, and the material of the short fibers mixed in the rubber is not specified. All synthetic fibers, natural fibers, etc. Can be used.

Further, as the friction member, instead of the rubber in which the short fibers are mixed, it is possible to use a synthetic resin in which the short fibers are mixed, felt, a flocking material, or the like.

According to a fifth aspect of the present invention, a feed roll rotated in the sheet feeding direction, a separation roll rotated in a direction opposite to the feed roll, and a torque applied to the separation roll and having a predetermined value or more act on the separation roll. And a torque limiter that allows the separation roll to rotate in the reverse direction. When the number of sheets is 1, the separation roll is rotated in the reverse direction by the rotational force of the feed roll to feed the sheet. Is premised on a paper feeding device in which only the paper on the feed roll side is fed, and the paper on the separation roll side is returned by the separation roll,
The torque limiter is a tubular first member into which torque is applied to the separation roll, and a cylinder that is coaxially fitted to the first member and is attached to the separation roll and has a plurality of window portions. -Shaped second member, a plurality of sliding members fitted into the window portion of the second member and contacting the outer surface of the first member, and mounted on the sliding member, A spring member for generating a frictional force is provided between the first member and the sliding member.

The invention according to claim 6 is office equipment such as a printer and a copying machine, and is provided with the paper feeding device according to claim 5.

[0017]

According to the first and second aspects of the invention, the plurality of sliding members (friction members) pressed against the outer surface of the first member by the spring force of the spring member are the second members. Of the second member and is restrained in the circumferential direction of the second member, but is movable in the radial direction thereof without being restrained. Therefore, the contact state between the sliding member (friction member) and the first member is stabilized, and a uniform contact surface pressure can be obtained.

According to the third aspect of the invention, the plurality of sliding members which are pressed against the outer surface of the friction member by the spring force of the spring member are fitted into the window portion of the second member, Although it is constrained in the circumferential direction of the member, it is movable in the radial direction without being constrained. Therefore, the contact state between the sliding member and the friction member is stabilized, and a uniform contact surface pressure can be obtained.

According to the fourth aspect of the invention, the short fibers are exposed from the rubber material on the outer surface of the friction member.
The surface of the sliding member corresponding to the surface where the short fibers are exposed is a resin surface made of a thermoplastic resin, whereby the friction interface is composed of the resin surface and the rubber surface where the short fibers are exposed. Therefore, it is not necessary to interpose a lubricant on the friction interface. In addition, short fibers exposed from the rubber material form many gaps (spaces) between the resin surface and the rubber surface, and the worn powder collects in these gaps, eliminating the adhesion and transfer of wear powder, Further, such abrasion powder is positively moved to the outside by the movement of the short fibers during frictional sliding and is discharged. Therefore, it takes a very long time until the abrasion powder is saturated in the gap between the short fibers, and as a result, stable torque is maintained for a long period of time.

According to the fifth and sixth aspects of the present invention, the stable torque is maintained for a long period of time, and the double feeding of the sheet is prevented.

[0021]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 to 4 showing the schematic structure, reference numeral 1 is a torque limiter for interrupting the transmission of torque when a torque of a certain value or more is applied, and a first tubular shape to which the torque is input. A rotary member 2 that is a member, a tubular friction member 3 that is attached and fixed to the outer peripheral portion of the rotary member 2 with an adhesive or the like, and a plurality of substantially rectangular window portions that are externally fitted to the rotary member 2. A plurality of slides that form a frictional interface between the tubular member 4 that is a tubular second member having the four members 4a, ... And the friction member 3 that is fitted into the window portions 4a of the tubular member 4. Moving member 5,
, And a spring member 6 mounted on the sliding members 5, and for generating a frictional force between the outer peripheral surface of the friction member 3 and the inner peripheral surfaces of the sliding members 5 ,. Spring member 6
The other members 2, 3, 4, and 5 except for are made of synthetic resin or rubber to reduce the weight.

The rotating member 2 and the tubular member 4 are fitted coaxially. The rotating member 2 includes a cylindrical portion 2a and a disc-shaped flange portion 2b that is continuously provided at one end of the cylindrical portion 2a.
And a center hole 2c penetrating both parts 2a, 2b is formed. On the outer peripheral portion of the cylindrical portion 2a of the rotating member 2,
A cylindrical friction member 3 is fitted and fixed by a fixing means such as an adhesive means or a spline means not shown so as not to move in the rotational direction.

The friction member 3 is made of short fiber compounded rubber in which short fibers are mixed, and the short fibers are exposed on the outer peripheral surface to which the inner peripheral surface of the sliding member 5 made of a thermoplastic resin is pressed. Has been. Therefore, the frictional interface is constituted by the short fiber compounded rubber surface by the friction member 3 and the thermoplastic resin surface by the sliding member 5, and it is necessary to interpose a lubricant such as molybdenum disulfide or grease at the frictional interface. Absent.

The cylindrical member 4 has a diameter larger than that of the cylindrical portion 2a of the rotating member 2 and is arranged at a constant interval from the cylindrical portion 2a, and the cylindrical portion 4b. Of the section 4b,
The rotary member 2 has a disc-shaped flange portion 4c that is continuously provided at the end opposite to the side where the rotary member 2 is fitted and has a disk-shaped flange portion 4c that has substantially the same diameter as the flange portion 2b of the rotary member 2. The windows 4a, ... Are regularly formed in the circumferential direction in the cylindrical portion 4b, and the flange 4
A center hole 4d corresponding to the center hole 2c is formed in the center of c.

Each of the sliding members 5, ... Is formed into a cylindrical body as a whole in a state of being fitted in the window portions 4a ,. The inner peripheral surface is the inner peripheral surface of the cylindrical member 4. It is located on the inner side and comes into contact with the outer peripheral surface of the friction member 3, and the outer peripheral surface has a diameter larger than the outer diameter of the tubular member 4 and projects outside the outer peripheral surface. Specifically, the outer diameter of the friction member 3 is d1, and the tubular member 4 is
When the outer diameter of the sliding member 5 is d2, the diameter D of the tubular member formed by the entire sliding members 5, ... And the thickness t of each sliding member 5 are determined based on the following equation.

D = d2 + α, α = 1 to 2 mm t = {(d2 + α) -d1} / 2 The sliding members 5, ... Are fitted to the window portions 4a of the tubular member 4. Therefore, the sliding members 5, ... Are constrained immovably in the circumferential direction and the axial direction of the tubular member 4, but are not constrained in the radial direction of the tubular member 4 and are movable.

With the above construction, when the rotating member 2 is rotated by the driving torque from the driving source (not shown), the friction member 3 attached and fixed thereto rotates together. If the driving torque acting on the rotating member 2 is not a torque equal to or more than a certain value, the sliding members 5, ... Are pressed against the outer peripheral surface of the friction member 3 by the spring force of the spring member 6, The driving torque is transmitted to the tubular member 4 via the sliding members 5, ..., The tubular member 4 rotates together with the rotating member 2, and the driving torque is transmitted from the rotating member 2 which is the power input member to the power output member. It is transmitted to a certain tubular member 4. At this time, the sliding members 5, ... Are fitted into the window portions 4a, ... Of the tubular member 4 and are constrained in the circumferential direction and the axial direction, but are movable in the radial direction, so that the sliding members 5 ,. By the spring force of the spring member 6 mounted on the outer side of the moving members 5, ..., The sliding members 5, ... Can be pressed uniformly against the friction member 3 without any restraining force in the radial direction. As a result, the drive torque (rotational torque) of the rotating member 2 is transmitted to the tubular member 4 without variations in torque and without fluctuation.

On the other hand, if the driving torque acting on the rotating member 2 is a torque equal to or more than a certain value, the torque is generated between the friction member 3 and the sliding members 5, ... By the spring force of the spring member 6. The torque due to the existing frictional force is overcome, slippage occurs between the friction member 3 and the sliding members 5, ..., And the transmission of the driving torque is interrupted.

Further, the friction member 3 is made of a rubber containing short fibers, and the short fibers are exposed from the rubber material on the outer peripheral surface against which the sliding members 5, ... Are pressed, while the short fibers are exposed. Since the inner surface of the sliding member 5 corresponding to the outer peripheral surface is the resin surface, the friction interface is composed of the resin surface and the rubber surface where the short fibers are exposed, and it is not necessary to interpose a lubricant. It is advantageous for maintenance. Also, since short fibers exposed from the rubber material form a lot of gaps between the resin surface and the rubber surface, wear powder accumulates in the gaps formed between the short fibers, and the wear powder adheres or moves. In addition to eliminating the possibility of adhesion, such wear particles are positively moved by the movement of the short fibers during frictional sliding and are extruded to the outside. Takes a very long time to be saturated, and as a result, stable torque can be maintained for a long period of time.

In the above embodiment, the cylindrical friction member 3
Is fixed to the outer peripheral portion of the rotating member 2, the friction member 11 is integrally provided on the sliding member 5 as shown in FIGS. It is also possible to make contact with the outer surface to form a friction interface, or, as shown in FIGS. 7 and 8, the friction member may be omitted and the sliding member 12 may be replaced by the rotation member 2 of the sliding member 12. It is also possible to configure so that the portion that comes into contact with the outer surface is the friction portion 12a that functions similarly to the friction members 3 and 12 described above.

Next, a paper feeding device using the above torque limiter will be described with reference to FIG.

In FIG. 9, reference numeral 31 is a stocker for stocking the paper P, and the stocked paper P is placed on a movable plate 33 which is constantly urged upward by a spring 32, and the stocker P is stocked. The paper P in 31 is taken out by the paper feed roll 34. A feed roll 35, which is rotated in the feed direction similarly to the paper feed roll 34, and a separation roll 36, which is rotated in the opposite direction, are arranged vertically opposite to each other on the paper feed roll 34 in the feed direction side. It is set up.

The separating roll 36 is provided with a torque limiter which allows the separating roll 36 to rotate in the reverse direction (rotate in the feeding direction) when a torque of a certain value or more is applied. As a result, when the number of the paper P taken out by the paper feed roll 34 is one, the separation roll 36 is forcibly rotated in the forward direction by the rotational force of the feed roll 35 to feed the paper, while the number of the paper P is two or more. At this time, only the paper P on the feed roll 35 side is fed, and the paper on the separation roll 36 side is returned by the reverse rotation of the separation roll 36.
Therefore, the torque of the torque limiter provided on the separation roll 36 is set to be smaller than the rotational driving force of the feed roll 35 and the frictional force between the sheets P, and larger than the frictional force between the sheets P. That is, if the friction coefficient between the feed roll 35 and the paper P is μF, the friction coefficient between the paper P is μP, and the friction coefficient between the paper P and the separation roll 36 is μR, the relationship of μF>μR> μP is maintained. It is necessary.

A copying machine using a paper feeding device having the above torque limiter will be described with reference to FIG.

In FIG. 10, reference numerals 40a and 40b denote conveyance paths for the recording paper 42 of the copying machine 41, and an electrostatic photographic image forming means 43 is arranged upstream of the conveyance path. The recording paper 42 stacked in the paper feed cassettes 44, 44 is fed to the paper feeding device 4
Then, the sheets are sent to the image forming means 43 one by one.
46 is a paper feed roll, 47 is a feed roll, and 48 is a separation roll provided with a torque limiter, which correspond to the rolls 34, 35 and 36 in FIG. 4, respectively.

In the electrostatographic image forming means 43, the right cylindrical photosensitive member 49 is rotationally driven in the direction of the arrow, the surface of the photosensitive member 49 is charged by the corona discharger 51, and the original document is exposed in the exposed area 52. The image is exposed to form an electrostatic latent image, and the electrostatic latent image is visualized as a toner image by using, for example, a magnetic brush of the developing device 53, and the recording paper 42 conveyed through the conveyance path 40a. The toner image on the photoconductor 49 is transferred by the transfer corona discharger 54, and the recording paper 42 is separated from the photoconductor 49 by the separation corona discharger 55. The recording paper 42 having the toner image transferred in this manner is conveyed by an endless belt 56 such as an aramid film belt provided on the conveying path 41a. The residual toner after the transfer of the photoconductor 42 is cleaned by the cleaning means 57.
Cleaned and removed by.

The original 6 is placed on a transparent plate 59 which is horizontally arranged above the machine body 58 to form an original image on the exposure area 52.
0 is placed and covered by the cover 62. The original 60 is illuminated from below the transparent plate 59 by a light source 63, and the original image is reflected by a reflecting mirror 64, a lens 65 and a reflecting mirror 6.
The light is guided to the exposure area 52 via the optical system 67 including 6. Slit exposure is performed by relatively moving the document 60 and a part of the optical system 67 in the left-right direction in FIG.
The recording paper 42 after transfer is mounted on the endless belt 56,
It is sandwiched between a pressure roll 69 and a heat roll 70 of a fixing device 68 provided on the downstream side in the recording paper conveyance direction, and heat fixed,
The recording paper 42 after the fixing is discharged from the paper discharge roll 71 onto the paper discharge tray 72.

The above embodiment is an example in which a paper feeding device using a torque limiter is used in a copying machine.
In addition, although not specifically shown, the same can be applied to a printer.

The present invention is not limited to the torque limiter of the above-mentioned type, but transmits torque from one member to the other member, and when the transmitted torque exceeds a certain value, slippage occurs. If it is a torque limiter that cuts off the transmission of torque by raising the torque, it can be applied to all torque limiters. In particular, in addition to the above-mentioned office equipment such as copiers and printers, it can be It is suitable for a light load torque limiter used in a double feed prevention or overload protection device for a paper feed section.

[0041]

As described above, the invention according to claims 1 and 2 includes a plurality of sliding members (friction members) which are pressed against the outer peripheral surface of the first member by the spring member, and Since the second member is fitted in the window portion of the member and the movement of the second member is restrained in the circumferential direction and the axial direction, it is possible to move without being restrained in the radial direction thereof.
The contact state between the sliding member (friction member) and the first member is stabilized, a uniform contact surface pressure is obtained, and variations and fluctuations in transmitted torque can be reduced. Further, by exchanging the spring member, the magnitude of the transmitted torque can be arbitrarily adjusted.

According to the third aspect of the present invention, as described above, the plurality of sliding members which are brought into pressure contact with the outer peripheral surface of the friction member by the spring member are fitted into the window portion of the second member, and the second member is fitted. The movement of the member is constrained in the circumferential direction and the axial direction, but it is allowed to move without being constrained in the radial direction, so that the contact state between the sliding member and the friction member is stabilized and uniform. It is possible to obtain a high contact surface pressure and reduce variations and fluctuations in transmitted torque.

In the invention according to claim 4, the sliding member is made of a thermoplastic resin, and the friction member is made of a short fiber compounded rubber in which the short fibers are exposed from the outer surface in contact with the sliding member. Therefore, it is not necessary to use a lubricant such as grease at the friction interface between the sliding member and the friction member, and it can be used for a long period of time without maintenance.

Since the inventions according to claims 5 and 6 use the torque limiter as described above, the torque suitable for preventing the double feeding of the sheet feeding in the sheet feeding device is maintained stably for a long period of time. Therefore, it is possible to prevent double feeding of the sheet for a long period of time. In particular, if the frictional interface of the torque limiter is made up of the resin surface and the rubber surface where the short fibers are exposed, it is not necessary to interpose a lubricant such as grease at the frictional interface, and the contamination of the paper feed by the lubricant is eliminated. You can eliminate the fear.

[Brief description of drawings]

FIG. 1 is a perspective view of a torque limiter.

FIG. 2 is a sectional view of the same.

FIG. 3 is an end view taken along line III-III in FIG.

FIG. 4 is a perspective view of a tubular member.

FIG. 5 is a view similar to FIG. 2 for another embodiment.

6 is an end view taken along line VI-VI of FIG.

FIG. 7 is a view similar to FIG. 2 for yet another embodiment.

8 is an end view taken along the line VIII-VIII in FIG.

FIG. 9 is a schematic explanatory diagram of a paper feeding device.

FIG. 10 is a schematic configuration diagram of a copying machine using a paper feeding device.

[Explanation of symbols]

 1 Torque limiter 2 Rotating member (1st member) 3 Friction member 4 Cylindrical member (2nd member) 4a Window part 5 Sliding member 5 Spring member 11 Friction member 12 Sliding member 12a Friction part 35 Feed roll 36 Separation Roll 41 Copier P Paper

Claims (6)

[Claims] 1. When a torque of a certain value or more is applied,
A torque limiter for interrupting torque transmission, comprising: a tubular first member to which torque is input; and a tubular second member coaxially fitted to the first member and having a plurality of window portions. Member, a plurality of sliding members fitted into the window portion of the second member and contacting the outer surface of the first member, and the sliding member provided to the sliding member. A torque limiter comprising: a spring member that generates a frictional force between the member and the sliding member. 2. The torque limiter according to claim 1, wherein the sliding member is integrally provided with a friction member that comes into contact with the outer surface of the first member. 3. When a torque above a certain value is applied,
A torque limiter for interrupting torque transmission, comprising: a tubular first member to which torque is input; a friction member attached and fixed to an outer peripheral portion of the first member; and a coaxial member to the first member. A tubular second member having a plurality of window portions, and a plurality of sliding members fitted into the window portions of the second member and contacting the outer surface of the friction member, A torque limiter provided to the sliding member, comprising a spring member for generating a frictional force between the friction member and the sliding member. 4. The torque limiter according to claim 3, wherein the sliding member is made of a thermoplastic resin, and the friction member is made of short fiber compounded rubber in which short fibers are exposed from the outer surface. 5. A feed roll which is rotated in a paper feed direction, a separation roll which is rotated in a direction opposite to the feed roll, and a separation roll which is applied to the separation roll when a torque of a certain value or more is applied. A torque limiter that allows reverse rotation is provided. When the number of sheets is one, the separating roll is rotated in reverse by the rotational force of the feed roll to feed the sheet, while when the number of sheets is two or more, the sheet on the side of the feed roll is fed. Sent only,
In the paper feeding device in which the sheet on the separation roll side is returned by the separation roll, the torque limiter is arranged coaxially with the cylindrical first member to which the torque to the separation roll is input, and coaxially with the first member. A tubular second member fitted and attached to the separation roll and having a plurality of windows, and a plurality of second members fitted into the windows of the second member and contacting the outer surface of the first member. Paper using a torque limiter, comprising: a sliding member; and a spring member that is mounted on the sliding member and that generates a frictional force between the first member and the sliding member. Feeder. 6. An office machine using a torque limiter, comprising the paper feeding device according to claim 5.