JP2005083540A - Torque limiter and rotating member using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque limiter usable for a sheet carrying mechanism and having a small size and high set torque, and to provide a rotating member using the same. <P>SOLUTION: The torque limiter comprises an outer cylinder member 2 having a truncated cone shaped hole portion 1, an internal insertion member 3 to be fitted to the hole portion 1 of the outer cylinder member 2, and a thrust means 4 arranged in a range of the axial length of the outer cylinder member 2 for thrusting the hole portion 1 of the outer cylinder member 2 in the direction of fitting the internal insertion member 3 in close contact therewith. In another aspect, it comprises the outer cylinder member 2 having the pair of truncated cone shaped hole portions 1 whose diameters are gradually reduced along the same center axis as tending inward from both end faces, the pair of internal insertion members 3 fitted to the hole portions 1 of the outer cylinder member 2 at both ends and adapted to be held between the pair of conical faces of the hole portions 1, and the thrust means 4 for thrusting the hole portions 1 of the outer cylinder member 2 in the direction of fitting the pair of internal insertion members 3 in close contact therewith. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a torque limiter, and more particularly to a small and high torque limiter applied to a sheet conveying mechanism of a sheet processing apparatus such as a copying machine or a printer, and a rotating member using the same.

Conventionally, in a sheet conveying mechanism of a sheet processing apparatus such as a copying machine or a printer, a torque limiter may be applied to, for example, a double feed prevention mechanism at the time of paper feeding.
As these torque limiters, for example, they are incorporated into a rotating body such as a transport roll, and friction type or magnet type are usually presented (for example, see Patent Documents 1 to 3).

The friction type (see Patent Document 2) has a driving rotor and a hollow driven rotating body configured to be relatively rotatable on the same axis. For example, a torsion coil spring is wound around the driving rotor. In addition, torque transmission from the driving rotating body to the driven rotating body by the frictional force between the driving rotating body or the driven rotating body and the torsion coil spring may be used.
Moreover, as a magnet type (refer patent document 3), it has a driving | running | working rotary body and a driven rotary body which were comprised rotatably relatively on the same axis | shaft. For example, a permanent magnet is arranged on the outer peripheral surface of the driving rotary body. In this case, a semi-rigid magnetic body is arranged on the peripheral surface of the driven rotating body so that torque is transmitted between both rotating shafts by the hysteresis torque of both magnetic bodies.

JP 2002-303335 A (column of embodiment of the invention, FIG. 2) JP 2000-161380 A (column of embodiment of the invention, FIG. 2) JP-A-6-221341 (Example column, FIG. 1)

Since the above-described friction type torque limiter is configured to incorporate a torsion coil spring inside the rotating body, the axial dimension of the rotating body inevitably has to ensure an accommodation space for the torsion coil spring. The body needs a certain width.
Therefore, in this friction type, it is difficult to incorporate it into a rotating member such as a thin gear or pulley.
Also, in this type of friction type, the degree of winding of the built-in torsion coil spring is adjusted with a handle or knob, and the contact pressure between the driving rotor or driven rotor and the torsion coil spring is set. The desired torque setting is performed.
However, the contact pressure between the torsion coil spring and the driving rotor etc. changes directly according to the operating force to the handle or knob, but there is a limit to the operating force to the handle or knob. Therefore, it is difficult to set the contact pressure sufficiently large, and it is difficult to perform a high set torque.
In addition, since the handle and the knob are arranged so as to protrude from the side of the rotating body, it is an inconvenient factor for the demand for downsizing the torque limiter.

On the other hand, in the above-described magnet type torque limiter, it is necessary to increase the length of the torque limiter or use an expensive magnetic material in order to obtain a high magnetic field in order to secure a hysteresis torque for increasing the set torque. .
In addition, this magnet type requires a process such as magnetization, and it is difficult to adjust the magnetic force, so it is difficult to realize a torque limiter with high accuracy and low cost.

Therefore, in these torque limiters, the application location in the sheet conveying mechanism is limited to application in a location where the set torque is low, such as a torque limiter for preventing double feeding.
For example, in the application example for preventing double feed, the set torque can be applied with a small value of about 98 mN · m (about 1000 gf · cm) or less, but for applications that require higher torque setting, It is difficult to apply.
As described above, the conventional torque limiter is incorporated in a relatively large element such as a transport roll and the set torque is limited to a low torque.
Further, when a torque limiter is incorporated in a drive transmission member such as a gear, the drive transmission member is usually disposed on the side of the torque limiter, which is insufficient for realizing a small drive transmission member.

However, a resin gear train, for example, is used as a drive transmission mechanism in a sheet conveyance mechanism of a sheet processing apparatus such as a copying machine or a printer, but this type of drive transmission mechanism is excessive for some reason. When torque is applied to this gear train, the gears in the gear train may be damaged, resulting in a situation in which the operation of the apparatus stops (it is necessary to replace damaged parts). Assuming this situation, a torque limiter is added to at least one of the gears that make up the gear train, and when excessive torque is applied, the torque limiter is activated to prevent excessive torque from being applied to the gear. In addition, it is required to prevent damage to other gears.
However, as described above, since the conventional torque limiter is relatively large and low in torque, it cannot be used as it is, and there is a strong demand for a torque limiter that is small and has a high set torque.
The present invention has been made to solve the above technical problems, and provides a torque limiter that is small and has a large set torque, and a rotating member that uses the torque limiter.

  In order to realize a rotating member such as a gear having a torque limiter function that is small and has a high set torque, the present inventor has a large conical clutch with a conical friction surface pressed by a relatively small axial direction. Focusing on the ability to transmit torque, we examined the application of this conical clutch to a torque limiter.

  That is, as shown in FIG. 1, the present invention includes an outer cylinder member 2 having a truncated cone-shaped hole 1, an insertion member 3 fitted in the hole 1 of the outer cylinder member 2, and the outer cylinder. And a pressing means 4 that presses in the direction in which the insertion member 3 is closely fitted into the hole 1 of the member 2 and is disposed within the axial length range of the outer cylinder member 2. Is.

In such technical means, the outer surface shape of the outer cylindrical member 2 is preferably a cylindrical shape from the viewpoint of application to a gear or the like, but is not limited thereto, and may be, for example, a quadrangle or the like. .
Further, the material of the outer cylinder member 2 is not limited to metal and may be resin.
On the other hand, the insertion member 3 may be a mode in which the rotating shaft 5 is integrally provided, the shaft 5 may be mounted and fixed to the insertion member 3, or the shaft 5 may be attached to the outside of the insertion member 3. Even if it is an aspect to provide, it does not interfere.
Further, the material of the insertion member 3 is preferably the same as the material of the outer cylinder member 2 from the viewpoint of stabilizing the set torque.

  Further, the pressing means 4 has a fastened portion on the side of the insertion member 3, and includes a fastening member that fastens the insertion member 3 so as to closely fit the outer cylinder member 2. From the viewpoint of this, it is preferable.

  In particular, as a preferred embodiment of the present invention, an outer cylinder member 2 having a pair of frustoconical hole portions 1 that are inward from both end faces and gradually reduce in diameter along the same central axis, and the outer cylinder member 2. A pair of insertion members 3 that can be fitted to the hole 1 from both sides and can be sandwiched between a pair of conical surfaces of the hole 1, and the pair of insertion members 3 in the hole 1 of the outer cylinder member 2, respectively. The aspect provided with the press means 4 pressed in the direction to closely fit is mentioned.

In this case, the pressing means 4 is provided with a fastened portion on one of the pair of insertion members 3 and a fastening member on the other, and the set torque is stabilized by fastening them with a predetermined pressure. Therefore, it is preferable.
Further, the pressing means 4 is provided with a fastened portion on one of the pair of insertion members 3 and a fastening member on the other, and these are fastened via an adjustment member, so that the set torque is further stabilized. This is preferable.

And it is also possible to adjust the set torque by providing a hollow recess on both end faces of the outer cylinder member 2. In addition, the bending rigidity of the outer cylinder member 2 is adjusted by providing this thinning recessed part, and setting torque reduces.
In addition, it is preferable that the hollow recess is provided in a circumferential shape, but a rib or the like may be provided as appropriate from the viewpoint of securing the strength of the rotating member, and a plurality of recesses are provided in the circumferential shape. Including.
Here, from the viewpoint of applying the torque limiter of the present case to a gear or the like, it is preferable to provide a rotation transmission portion around the outer cylindrical member 2. In addition, this rotation transmission part may be comprised integrally with the outer cylinder member 2, and may be comprised separately from the outer cylinder member 2.

According to the present invention, the conical surface of the insertion member is closely fitted to the truncated cone-shaped hole of the outer cylinder member, and the angle of the conical surface is configured within a predetermined angle range (1 to 60 °). As a result, the friction surface with respect to the length in the axial direction is widened, and an effective frictional force due to the wedge effect can be obtained. Therefore, it is possible to provide a torque limiter that is small and has a large set torque.
In particular, in a mode in which the outer cylinder member is sandwiched between the pair of insertion members, the friction surface is further expanded, and thus a larger set torque is obtained. In addition, by fastening the pair of insertion members to each other, the influence of the fastening is only the friction surface, so there is a possibility that the adjustment of the set torque can be simplified. Therefore, it is possible to provide a torque limiter having a small size and a wider range of set torque, which is effective.
Furthermore, by providing a rotation transmitting portion on the outer periphery of the torque limiter, it is possible to provide a rotating member that incorporates a torque limiter that is small and has a large set torque.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 2 is an explanatory diagram showing the sheet conveying mechanism 10 of the sheet processing apparatus to which the first embodiment of the torque limiter according to the present invention is applied.
In the figure, a sheet conveying mechanism 10 is composed of a pair of conveying rolls 11 and 12 (specifically, a driving conveying roll 11 and a driven conveying path roll 12) used for conveying a sheet S and the like. The conveying gear 13 is mounted on the drive conveying roll 11 side and has a gear portion on the outer periphery thereof. The driving gear 30 meshes with the conveying gear 13 and includes a torque limiter 20 inside.
In this example, the drive transmission gear 30 is formed by integrally forming a gear portion 21 a on the outer periphery of the torque limiter 20.
A drive shaft 23 is attached to the center of the torque limiter 20, and the drive transmission gear 30 is rotated via the torque limiter 20 by rotating the drive shaft 23 by a motor 31 as an external drive source. ing.

Here, the torque limiter, which is a feature point of the present case, will be described with reference to FIGS. FIG. 3B is a cross-sectional view taken along D in FIG.
In the figure, a torque limiter 20 includes an outer ring 21 (having a pair of conical surfaces of A and B portions) as an outer cylinder member having a truncated cone-shaped hole, and the pair of cones. A pair of inner rings 22a and 22b is provided as an insertion member having a conical surface to be fitted to the surface.
Each of the pair of inner rings 22a and 22b has a male screw portion or a female screw portion (corresponding to a C portion) so as to be fastened to each other. In this example, the inner ring 22a has a male thread portion, and the inner ring 22b has a female thread portion.
Furthermore, a drive shaft 23 is attached to one inner ring 22a, and a D-cut 23a is provided on a part of the drive shaft 23 to prevent the drive shaft 23 from rotating freely with the inner ring 22a. Yes.

In the torque limiter 20 in this example, the inner ring 22a and the other inner ring 22b to which the drive shaft 23 is attached are inserted from both end surfaces of the outer ring 21, and the conical surfaces (the A and B portions of the outer ring 21 are inserted). The inner rings 22a and 22b are screwed and fastened so that the conical surface of the outer ring 21 and the conical surfaces of the inner rings 22a and 22b are closely fitted to each other.
At this time, a method based on a plastic zone angle method is adopted for this fastening, and after fastening with a predetermined fastening torque, for example, by further fastening an angle of 60 °, the fastening portion exceeds the elastic region and becomes a plastic zone. Therefore, accurate fastening is performed, and variation in the set torque as the torque limiter 20 is reduced.

  For this reason, the torque limiter 20 in this example has the conical surface of the outer ring 21 and the conical surface of the inner ring 22 (22a, 22b) closely fitted, so that the wedge effect is effective and the torque limiter having a large set torque is obtained. 20 can be realized. In addition, since the pair of inner rings 22 are screwed together, the set torque can be easily adjusted, and the adjustment portion can be adjusted within the axial length range of the outer ring 21, so that a small torque can be obtained. The limiter 20 can be realized.

In the torque limiter 20 in this example, when the load applied to the outer ring 21 is equal to or lower than the set torque (less than idling torque), the outer ring 21 also rotates as the inner ring 22 rotates.
Therefore, when a high load exceeding the set torque is applied to the outer ring 21, slippage between the outer ring 21 and the inner ring 22 at the conical surface occurs, and the inner ring 22 rotates idly.

Here, the specific operation of the sheet conveying mechanism 10 according to the present embodiment when the torque limiter 20 described above is used will be described with reference to FIG.
Now, the drive shaft 23 of the torque limiter 20 is rotated by the drive force from the motor 31 of the external drive source, and the inner ring 22 is rotated in the direction of the solid line arrow in the figure.
At this time, no slip occurs on the conical surface between the inner ring 22 and the outer ring 21 due to the set torque of the torque limiter 20, and therefore the rotation direction of the outer ring 21 is the same direction as the inner ring 22 (solid arrow in the figure). Direction).
The rotational direction of the torque limiter 20 is transmitted to the transport gear 13 side by a gear portion 21 a provided on the outer periphery of the outer ring 21 of the torque limiter 20. The drive conveyance roll 11 is rotated by the rotational force transmitted to the conveyance gear 13 to convey the sheet S. The driven transport roll 12 is rotated in conjunction with the drive transport roll 11.

Therefore, when the transport roll is in operation, if an overload is applied to the transport roll due to some trouble, the force is applied to the torque limiter 20 via the transport gear 13, and the outer ring 21 of the torque limiter 20 is applied. The torque indicated by T2 (broken arrow) in the figure is applied.
At this time, when the torque indicated by T2 becomes larger than the set torque of the torque limiter 20 (torque indicated by the broken arrow T1 in the figure), the conical surface between the outer ring 21 and the inner ring 22 of the torque limiter 20 ( (Friction surface) cannot be maintained, and slipping occurs on this surface, and the rotation of the outer ring 21 rotates in a direction different from the rotation direction of the inner ring 22 (when the drive conveyance roll 11 stops, the outer Ring 21 also stops).
Further, when the cause of the overload is eliminated and the operation of the drive transport roll 11 becomes normal, the torque T2 of the outer ring 21 decreases, and the outer ring 21 starts rotating in the same direction as the inner ring 22 again. .
Since such a configuration is adopted, the conveyance gear 13 and the like can be prevented from being damaged, and when the cause of an overload or the like is removed, it can be naturally restored.
Furthermore, since the outer ring 21 having a conical surface is sandwiched and tightened from both sides by the conical surface of the inner ring 22, the gear portion 21a is less likely to be shaken even when the torque limiter 20 of the present embodiment is idle.

As described above, the drive transmission gear 30 according to the present embodiment employs a configuration in which the built-in torque limiter 20 sandwiches the outer ring 21 between the pair of inner rings 22a and 22b. In addition to the need for a means, since the gear portion 21 a is provided on the outer periphery of the outer ring 21, a small drive transmission gear 30 incorporating a small torque limiter 20 can be realized.
In the present embodiment, an example of the drive transmission gear 30 incorporating the torque limiter 20 has been shown. However, the present invention is not limited to the drive transmission gear 30, and for example, the torque limiter 20 of the present invention is applied to a retard roll as a drive roll of a sheet feeding mechanism. In this case, the torque limiter 20 may be disposed on the side end of the retard roll.
Furthermore, the conical surfaces are provided on both sides and arranged so as to push each other in the axial direction, so that a large friction surface can be obtained and the set torque can be increased by the wedge effect. Therefore, it is possible to realize a small torque limiter 20 having a large set torque.
In addition, since the torque limiter 20 in the present embodiment has a small configuration, it can be incorporated into other parts such as a shaft.

Embodiment 2
4 (a) and 4 (b) are explanatory views showing an outline of the embodiment 2 of the drive transmission gear 30 with a built-in torque limiter according to the present invention, wherein (a) is a sectional view and (b) is a partially enlarged view. is there.
In the figure, a torque limiter 20 built in the drive transmission gear 30 in the present embodiment is configured in substantially the same manner as the torque limiter 20 in the first embodiment, but a pair of inner rings 22a and 22b are fastened. A spacer 24 (a plurality of spacers are used in this example) is sandwiched in the space (corresponding to the E portion) at the time, and the two inner rings 22a and 22b are fastened together via the spacer 24. This is different from the first embodiment.

  This space (corresponding to the E portion) is provided to absorb variations in parts processing of the outer ring 21 and the inner ring 22, and the inner rings 22a and 22b are fastened by inserting the spacer 24 therein. The axial lengths of the conical surfaces when mating can be made uniform, the set torque is stabilized, and adjustment of the set torque is facilitated by appropriately selecting the spacer 24.

Embodiment 3
FIG. 5 is an explanatory diagram showing an outline of the third embodiment of the drive transmission gear 30 with a built-in torque limiter according to the present invention.
In the figure, the torque limiter 20 built in the drive transmission gear 30 in the present embodiment is configured in substantially the same manner as the torque limiter 20 in the first embodiment, but is circumferentially formed on both surfaces of the outer ring 21. The point provided with the slit 25 is different from the first embodiment.
The slit 25 is provided to finely adjust the set torque of the torque limiter 20, and by bending the outer ring 21, the bending rigidity changes and deflection occurs, so that the set torque is reduced. It has become.
The torque limiter 20 of this example is easy to realize particularly in the case of resin (preferably polyacetal resin: POM).
Moreover, although the aspect provided with the slit 25 in the circumferential shape was shown in this example, the rib is not limited to the circumferential shape, and a rib can be appropriately provided in the slit 25. Furthermore, it may be a mode in which a concave portion is appropriately provided instead of the slit 25, and it is preferably provided in a circumferential shape.

Embodiment 4
FIG. 6 is an explanatory view showing an outline of the fourth embodiment of the drive transmission gear with a built-in torque limiter according to the present invention.
In the same figure, unlike the torque limiter 20 in the first embodiment, the torque limiter 20 built in the drive transmission gear 30 in the present embodiment has only one conical surface that determines the set torque of the torque limiter 20. (Only one part of part A).
Components similar to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is also omitted.

In the present embodiment, an inner ring 22 having a male threaded portion (corresponding to part C) at one end is fitted to the outer ring 21 having a hole having a conical surface (corresponding to part A). Yes.
Further, in the close fitting of the inner ring 22 and the outer ring 21, a nut 26 is fastened to the male thread portion of the inner ring 22, and this nut 26 is in close contact with the outer ring 21 at the F portion in the figure. . At this time, the nut 26 is fastened within a range not exceeding the axial length of the outer ring 21.
Further, a drive shaft 23 is attached to the inner ring 22 so as to rotate integrally with the inner ring 22.

In the present embodiment, the set torque is determined by the conical surface (corresponding to part A in the drawing) and the contact surface between the nut 26 and the outer ring 21 (corresponding to part E in FIG. 3). Since the area is narrower and there is no wedge effect, the set torque is almost determined by the conical surface.
Therefore, also in the present embodiment, the operation as the torque limiter 20 is possible.

The torque limiter in the present embodiment was implemented by adopting the configuration of FIG. 3, and the following set torque was obtained.
In this embodiment, the inner ring and the outer ring use brass whose surface is barrel-polished, φ20 mm, width 10 mm, conical surface angle 5 ° (relative to the axial direction), and a brass flat washer 0.1 mm as a spacer. A torque limiter using three pieces of thickness was produced.
Then, the two inner rings are fastened by a plastic zone angle method via a spacer to eliminate the influence of the friction coefficient of the screw portion.
As a result, a torque limiter with a set torque (rotational torque) of 980 mN · m (about 10 kgf · cm) was realized.

In this example, if the brass was cut as the inner ring and the outer ring, the friction performance on the cutting surface became unstable, so that barrel-polished ones were used. It is also possible to stabilize the performance by applying a Teflon (registered trademark) coating or by applying a lubricating oil.
In this example, brass is used for the inner ring and the outer ring. However, for example, cast iron may be used, or a resin may be used. The set torque is appropriately set according to the angle of the conical surface (inclination angle from the axial direction), the material, and the like.

It is explanatory drawing which shows the outline | summary of the torque limiter which concerns on this invention. It is explanatory drawing which shows the sheet | seat conveyance mechanism of the sheet processing apparatus with which the torque limiter which concerns on Embodiment 1 to which this invention was applied was applied. (A) (b) is explanatory drawing which shows the structure of the torque limiter of Embodiment 1. FIG. (A) (b) is explanatory drawing which shows the outline of the drive transmission gear which incorporated the torque limiter based on Embodiment 2 to which this invention was applied. It is explanatory drawing which shows the outline of the drive transmission gear which incorporated the torque limiter which concerns on Embodiment 3 to which this invention was applied. It is explanatory drawing which shows the outline of the drive transmission gear which incorporated the torque limiter which concerns on Embodiment 4 to which this invention was applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hole part, 2 ... Outer cylinder member, 3 ... Insertion member, 4 ... Pressing means, 5 ... Shaft

Claims (7)

An outer cylinder member having a frustoconical hole,
An insertion member that fits into the hole of the outer cylinder member;
A torque limiter comprising: pressing means that presses in a direction in which the insertion member is closely fitted into the hole of the outer cylinder member and is disposed within the axial length range of the outer cylinder member. . The torque limiter according to claim 1,
The pressing means has a fastened portion on the insertion member side,
A torque limiter, comprising: a fastening member that fastens the inner insertion member so as to closely fit the outer cylinder member. An outer cylinder member having a pair of frustoconical hole portions that are inward from both end faces and gradually reduce in diameter along the same central axis;
A pair of insertion members fitted into the hole of the outer cylinder member from both sides and sandwiched between the pair of conical surfaces of the hole;
A torque limiter comprising pressing means for pressing the pair of insertion members in close contact with the holes of the outer cylinder member. The torque limiter according to claim 3,
The pressing means is provided with a fastened portion on one of the two insertion members, and a fastening portion that can be fastened on the fastened portion on the other, and fastens them with a predetermined pressure against the conical surface of the insert member. A rotating member with a built-in torque limiter, characterized in that The torque limiter according to claim 3,
The pressing means is characterized in that a fastened portion is provided in one of the two insertion members, a fastening portion that can be fastened to the fastened portion is provided in the other, and these are fastened via an adjusting member. Torque limiter. The torque limiter according to claim 3,
A rotating member with a built-in torque limiter, characterized in that the outer cylinder member has thinned recesses on both end faces thereof.   A rotation member comprising a rotation transmission portion around the outer cylinder member of the torque limiter according to claim 1.

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