JP2002070883A - Revolution transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a revolution transmission device which is small-sized and in which reduction of transmission torque is very little, with simple construction and with low cost. SOLUTION: An axial length of a half rigid magnetic body 5 which rotates along with a second rotating shaft 6 is formed to be equal to or be shorter than an axial length of a permanent magnet 3 which rotates along with a first rotating shaft 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation transmitting device used for a paper feeding device such as a copying machine or a printer.

[0002]

2. Description of the Related Art For example, Japanese Utility Model Publication No. 7-3082 discloses
A conventional rotation transmitting device used as a torque limiter in a paper feeding device of a copying machine is disclosed. FIG. 9 is an axial sectional view of this conventional rotation transmitting device.

The rotation transmitting device 1 includes a first rotating shaft 2, a cylindrical permanent magnet 3 disposed on the first rotating shaft 2, and one of the permanent magnets 3 via a washer or a sliding film 4. A second rotating shaft 6 arranged so as to abut on the side end face;
A cylindrical hiss plate 5 made of a semi-hard magnetic material fixed to the inner peripheral surface of the second rotating shaft 6 by press fitting so as to face the permanent magnet 3, and fixed to the outer periphery of the second rotating shaft 6 by bonding. Rubber roller 7. The first rotation shaft 2 and the second rotation shaft 6 are coaxially arranged so as to be rotatable with each other.

When the second rotating shaft 6 is in contact with one end face of the permanent magnet 3 via the washer 4, both ends of the hiss plate 5 in the axial direction are separated from both ends of the permanent magnet 3 in the axial direction. Is also protruding. In this state, the axially protruding length α at one end of the hiss plate 5 is larger than the axially protruding length β at the other end. Due to the difference in the protruding length, the hiss plate 5 is magnetically attracted by the permanent magnet 3 toward the other side (the side with the smaller protruding length).

That is, the magnetic attraction force always acts so as to maintain the contact state between the second rotating shaft 6 and the permanent magnet 3 via the sliding film 4, and the first and second rotating shafts 2, 6 Can be maintained in a predetermined positional relationship. At this time, the permanent magnet 3 is sandwiched between the washer 4 and the annular convex portion 2d formed integrally with the first rotating shaft 2 to prevent the permanent magnet 3 from being displaced in the axial direction during operation.

To separate the first rotating shaft 2 and the second rotating shaft 6 from each other, the first rotating shaft 2 is slid to the right and the second rotating shaft 6 is slid to the left. By doing so, it can be easily removed manually.

In the above configuration, when the first rotating shaft 2 is driven to rotate by a sheet feeding motor (not shown), the permanent magnet 3 fixed to the first rotating shaft 2 rotates, and the permanent magnet 3 and the hiss plate 5 are rotated.
The second rotation shaft 6 is rotated by the hysteresis torque between. As a result, the rubber roller 7 rotates and sends out the copy sheet.

[0008]

As described above, when the second rotating shaft 6 is in contact with one end surface of the permanent magnet 3 via the washer 4, one end of the hiss plate 5 in the axial direction is provided. Protrudes from the axial end of the permanent magnet 3 by a length α, and the other end protrudes by a length β. For this reason, it is necessary to form an expensive semi-hard magnetic material, which is a material of the His plate, for a long time, and there is a problem that the entire apparatus becomes expensive. Further, since the length of the semi-rigid magnetic hiss plate is lengthened, the overall length of the device becomes longer and the device becomes larger.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotation transmitting device which is small in size and hardly reduces transmission torque with a simple structure and at low cost.

[0010]

In order to achieve the above object, the invention according to claim 1 comprises a first rotating shaft, a cylindrical permanent magnet disposed on the first rotating shaft, A second part of which abuts one end face of the first rotating shaft or one of the permanent magnets
And a cylindrical semi-hard magnetic body disposed on the second rotation axis and facing the peripheral surface of the permanent magnet. The first semi-hard magnetic body is provided with a hysteresis torque between the permanent magnet and the semi-hard magnetic body.
In the rotation transmitting device for transmitting rotation between the rotating shaft and the second rotating shaft, the axial length of the semi-hard magnetic material is equal to or shorter than the axial length of the permanent magnet. It is characterized by the following.

As described above, since the axial length of the semi-hard magnetic body is formed to be equal to or shorter than the axial length of the permanent magnet, a low-cost and small-sized rotation transmission device is provided. Can be provided.

In the invention according to claim 2, the semi-hard magnetic material is arranged so that the entire peripheral surface thereof faces the peripheral surface of the permanent magnet. With this arrangement, it is possible to prevent a decrease in the hysteresis torque between the semi-hard magnetic body and the permanent magnet.

In the invention according to claim 3, the axial displacement of the permanent magnet is regulated by a pair of sandwiching means provided opposite to both ends of the permanent magnet in the axial direction. With this configuration, the axial position of the permanent magnet is suppressed from being fluctuated by the pair of holding means, so that stable torque transmission can be achieved.

In the invention according to claim 4, the length of the axial displacement between one end of the permanent magnet and the one end of the semi-hard magnetic material, and the axial displacement between the two ends at the other end. The length of the displacement is made equal. In this configuration, since no magnetic force is generated to displace the semi-hard magnetic body in the axial direction, the friction torque between the end face of the permanent magnet or the end face of the first rotating shaft and the second rotating shaft becomes substantially zero. That is,
Only the hysteresis torque between the semi-hard magnetic body and the permanent magnet acts as the transmission torque. The friction torque is usually easy to change, and may be a cause of fluctuation of the transmission torque. On the other hand, the hysteresis torque is stable. In the above configuration, the unstable friction torque is reduced to almost zero,
Since only the stable hysteresis torque is used, a rotation transmission device with stable transmission torque can be provided.

In the invention according to claim 5, the length of the axial misalignment between the permanent magnet and the semi-hard magnetic body on the side where the second rotating shaft contacts the first rotating shaft or the permanent magnet. Is shorter than the length of the axial displacement between them at the other end. As a result, the permanent magnet is attracted by a strong attraction force in one direction so as to reduce the difference between the lengths of the misalignment at both ends, and the permanent magnet end face or the end face of the first rotating shaft and the second rotating shaft are separated from each other. , A relatively large friction torque is generated. In this case, since the hysteresis torque and the friction torque are used together, a high torque value can be obtained.

In the invention according to claim 6, a projection is formed on at least one end in the axial direction of the permanent magnet so as to project toward the semi-hard magnetic body. With this configuration, a new hysteresis torque is generated between the protrusion of the permanent magnet and the semi-hard magnetic material, and the overall hysteresis torque increases.

In the invention according to claim 7, the ratio Ln / Lr of the length Ln in the axial direction of the permanent magnet to the length Lr in the axial direction of the semi-hard magnetic material is adjusted to be 1.00 to 1.25. did. If the length ratio Ln / Lr is in the range of 1.00 to 1.25, the reduction of the hysteresis torque is hardly observed, and a small and low-priced rotation transmission device can be provided with a simple configuration.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals in each drawing including the conventional apparatus shown in FIG. 9 indicate the same or corresponding elements, and thus the duplicated description will be omitted.

In the rotation transmitting device 1 shown in FIG. 1, the second rotating shaft 6 is composed of a cylindrical body 6a having a bottomed cylindrical shape and a lid 6b having a cylindrical portion 6c. Cylindrical body 6a and lid 6
Before fitting with b, the cylindrical hiss plate 5, which is a semi-hard magnetic material, is pressed into the inner peripheral surface of the cylindrical body 6a. Since the press-fitting machine has a position adjusting stopper, the press-fitting position of the hiss plate 5 can be arbitrarily determined. The inner diameter of the cylindrical portion 6c of the lid 6b is set to be larger than the outer diameter of the hiss plate 5, so that when the lid 6b is press-fitted into the cylindrical body 6a, the hiss plate 5
Does not occur. Note that a positioning stopper may be provided on the inner diameter portion of the cylindrical portion 6c of the lid 6b so that the hiss plate 5 can be reliably positioned.

The first rotating shaft 2 has an annular flange portion 2a.
Are formed integrally, and the permanent magnet 3 is sandwiched between the flange portion 2a and the sliding film 4 so that the permanent magnet 3
Is prevented from shifting in the axial direction. Note that a flange portion may be prepared separately from the first rotating shaft, and the flange portion may be fixed to the first rotating shaft by fitting or bonding. Alternatively, as shown in FIG. 2, a step 2 b is formed on the rotating shaft 2, and the step 2 b and the sliding film 4 form a permanent magnet 3.
May be sandwiched.

The axial length of the cylindrical hiss plate 5 is equal to the axial length of the cylindrical permanent magnet 3. Therefore, the price of the hiss plate is reduced, and a small and low-priced rotation transmission device can be provided.

Further, the entire inner peripheral surface of the hiss plate 5 is
Since the mounting position of the hiss plate 5 is adjusted so as to face the outer peripheral surface, the decrease in the hysteresis torque between the hiss plate 5 and the permanent magnet 3 is small and negligible.
Further, the second rotating body 6 is in contact with one end surface of the permanent magnet 3 via the washer or the sliding film 4. Therefore, for example, when an external biasing force acts on the rotating shaft in the axial direction, a sliding torque (friction torque) is generated in the sliding film 4. This sliding torque is used for transmitting the torque in addition to the hysteresis torque between the hysteresis plate 5 and the permanent magnet 3, so that the overall torque hardly decreases.

FIG. 3 is a cross-sectional view of the permanent magnet 3, and FIG.
FIG. 3 is a cross-sectional view of the first rotating shaft 2. As shown in FIG. 3, the permanent magnet 3 is formed in a cylindrical shape, and has a flat portion 3 on its inner surface.
a are formed to face each other. As shown in FIG. 4, a flat portion 2 c is formed on the outer surface of the first rotating shaft 2.
It is formed so as to correspond to a. By attaching the permanent magnet 3 formed as described above to the first rotating shaft 2, the permanent magnet 3 is prevented from being displaced in the circumferential direction. The permanent magnet 3 may be fixed to the first rotating shaft 2 by bonding or the like.

FIG. 5 is a half sectional view in the axial direction of a rotation transmitting device according to another embodiment of the present invention. In FIG. 5, the length of the hiss plate 5 in the axial direction is shorter than the length of the permanent magnet 3 in the axial direction. The hiss plate 5 is arranged substantially at the center of the permanent magnet 3 in the axial direction. Therefore, the length γ of the axial displacement between one end of the permanent magnet 3 and the one end of the hiss plate 5 and the length δ of the axial displacement between the two at the other end. They are equal (γ = δ). With this arrangement, the sliding torque between the permanent magnet 3 and the second rotating shaft 6 becomes substantially zero. Although the magnitude of the sliding torque slightly fluctuates, in this embodiment, the sliding torque becomes almost zero, so that almost the hysteresis torque acts as the transmission torque, and stable torque transmission can be achieved.

The length of the hiss plate 5 in the axial direction is Lr, and the permanent magnet 3
Is Ln, Ln / Lr is 1-1.
It is set to fall within the range of 25. Within this setting range, the decrease in hysteresis between the hiss plate 5 and the permanent magnet 3 is very small and can be almost ignored. This is a finding obtained by a measurement test performed by the present inventor.

The inventor of the present application measured the relationship between the magnet surface length difference and the torque using the apparatus having the structure shown in FIG. FIG. 6 shows the result. The vertical axis of the graph in FIG. 6 indicates the magnitude of the torque, and the horizontal axis indicates the difference (Lr) between the axial length (surface length) Lr of the hiss plate 5 and the axial length (surface length) Ln of the permanent magnet 3. -L
n).

In FIG. 6, the difference in surface length is -4 mm (Ln /
In a range of Lr = 1.25) to 0 mm (Ln / Lr = 1.00), the torque is about 375 gf · cm to about 420 gf.
-The value is cm, which means that there is no practical problem. In particular, the surface length difference is -2 mm (Ln / Lr = 1.11)
It can be seen that in the range of ０0 mm (Ln / Lr = 1.00), the decrease in torque is so small as to be almost negligible.

FIG. 7 is a half sectional view in the axial direction of a rotation transmitting device according to still another embodiment of the present invention. Also in this embodiment, Ln / Lr is set to fall within the range of 1 to 1.25. When assembling, slide film 4
The fixing position of the hiss plate 5 is adjusted such that the distance γ between the end face of the hiss plate 5 on the side and the end face of the permanent magnet 3 is shorter than the distance δ between the respective end faces on the opposite side. By such adjustment, during operation, the permanent magnet 3 is attracted to the second rotating shaft 6 side through the sliding film 4 with a strong attractive force,
Strong sliding torque is generated. Since this strong sliding torque is added to the hysteresis torque, a high torque value can be obtained without substantially reducing the total torque.

[0029]

[Table 1]

Table 1 shows that the axial length Lr of the hiss plate 5 is longer than the axial length Ln of the permanent magnet 3 (for example, the prior art of FIG. 9), equal (for example, the embodiment of FIG. 1), and short. The second rotating body 6 in the case (for example, the embodiment of FIG. 7)
The drawing shows the attraction force of the permanent magnet 3 toward the side (sliding film 4 side). As is clear from Table 1, when the axial length Lr of the hiss plate 5 is shorter than the axial length Ln of the permanent magnet 3,
The attractive force for attracting the permanent magnet 3 toward the second rotating shaft 6 is 17
It can be seen that the maximum is 0 g. This means that, during the operation of the rotation transmitting device, a strong attractive force acts on the permanent magnet 3 to be attracted to the second rotating shaft 6 side, and a strong sliding torque is generated, as described above. .

Further, this tendency is caused by the distance γ between the end face of the hiss plate 5 and the end face of the permanent magnet 3 on the sliding film 4 side.
However, if the position of the hiss plate 5 is adjusted so as to be shorter than the distance δ between the respective end faces on the opposite side, the strength becomes stronger.

If γ = δ, the friction torque becomes zero theoretically. Suction is a different concept from friction. If the hiss plate 5 is longer than the permanent magnet 3, the hiss plate 5 can receive the magnetic force from the permanent magnet 3 with a margin. That is, the magnetic line density at the end is small. On the other hand, when the hiss plate 5 is shorter than the permanent magnet 3, the short hiss plate attempts to receive the total magnetic force from the permanent magnets, and thus the magnetic line density increases. It is considered that this line density of magnetic force corresponds to the pull-out force. When the length of the hiss plate 5 is equal to or shorter than that of the permanent magnet 3, the arrangement relationship is γ.
= Δ is slightly larger than in the case of the prior art, so that a friction torque is easily generated.

FIG. 8 is an axial sectional view of a rotation transmitting device according to still another embodiment of the present invention. In this example,
The length of the hiss plate 5 in the axial direction is shorter than the length of the permanent magnet 3 in the axial direction.
A protruding portion (flange portion) 3a protruding toward the hiss plate 5 is formed on the end portion of the main body. Although the hysteresis torque is reduced due to the short length of the hysteresis plate 5, the hysteresis torque is newly generated between the flange portion 3a and the hysteresis plate 5, so that the reduction can be sufficiently compensated for.

In this embodiment, the flange 3a is formed at one axial end of the permanent magnet 3, but may be formed at the opposite end or both ends.

Although some embodiments have been described with reference to the drawings, they have been described by way of example only to specifically illustrate the invention. Therefore, many modifications and changes can be made to the embodiments described herein within the scope of the invention.

[0036]

As described above, according to the present invention, the axial length of the semi-hard magnetic body that rotates together with the second rotating shaft is set to the first length.
Since the length of the permanent magnet that rotates together with the rotating shaft is equal to or shorter than the axial length, a small and inexpensive rotation transmitting device can be provided with a simple configuration.

Further, by arranging the entire peripheral surface of the semi-hard magnetic body so as to face the peripheral surface of the permanent magnet, a decrease in the hysteresis torque can be suppressed.

If the displacement of the permanent magnet in the axial direction is restricted by the pair of holding means, stable torque transmission can be achieved.

If the length of the axial displacement between one end of the permanent magnet and the one end of the semi-hard magnetic material is equal to the length of the axial displacement between the two at the other end,
A rotation transmission device with stable transmission torque can be provided.

On the other hand, the length of the axial misalignment between the permanent magnet and the semi-hard magnetic material on the side where the second rotating shaft is in contact with the first rotating shaft or the permanent magnet is determined by the length of both ends at the other end. If the length is smaller than the length of the axial displacement between them, a relatively large friction torque is generated between the end surface of the permanent magnet or the end surface of the first rotating shaft and the second rotating shaft, so that the hysteresis torque and the friction torque are reduced. , A high torque value can be obtained.

The ratio Ln / Lr of the axial length Ln of the permanent magnet to the axial length Lr of the semi-hard magnetic material is 1.00 to 1.0.
If the configuration is set to be 25, a reduction in the hysteresis torque is hardly observed, and a small-sized and low-priced rotation transmission device can be provided with a simple configuration.

If a protrusion protruding toward the semi-hard magnetic body is formed on at least one end in the axial direction of the permanent magnet, a new hysteresis torque is generated between the semi-hard magnetic body and the protrusion. , The overall hysteresis torque increases.

[Brief description of the drawings]

FIG. 1 is an axial half-sectional view of a rotation transmission device according to an embodiment of the present invention.

FIG. 2 is an axial half-sectional view of a rotation transmission device according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a permanent magnet included in the rotation transmitting device shown in FIG.

FIG. 4 is a cross-sectional view of a first rotation shaft that forms the rotation transmission device shown in FIG.

FIG. 5 is an axial half-sectional view of a rotation transmission device according to still another embodiment of the present invention.

FIG. 6 is a diagram showing a magnitude of torque with respect to a difference between a surface length of a hiss plate and a surface length of a permanent magnet according to the present invention.

FIG. 7 is an axial half-sectional view of a rotation transmission device according to still another embodiment of the present invention.

FIG. 8 is an axial half-sectional view of a rotation transmission device according to still another embodiment of the present invention.

FIG. 9 is an axial sectional view showing a conventional rotation transmission device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Torque limiter 2 ... 1st rotating shaft 3 ... Permanent magnet 3a ... Projection 4 ... Sliding film 5 ... Semi-hard magnetic material 6 ... 2nd rotating shaft In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (7)

[Claims] 1. A first rotating shaft, a cylindrical permanent magnet disposed on the first rotating shaft, and a part of the first rotating shaft or one end face of the permanent magnet abuts on the first rotating shaft. A second rotating shaft, and a cylindrical semi-hard magnetic body disposed on the second rotating shaft and facing the peripheral surface of the permanent magnet; In a rotation transmitting device that transmits rotation between the first rotation shaft and the second rotation shaft by a hysteresis torque, an axial length of the semi-hard magnetic body is equal to an axial length of the permanent magnet. Or a rotation transmission device formed shorter than that. 2. The rotation transmitting device according to claim 1, wherein the semi-hard magnetic body is arranged so that an entire peripheral surface thereof faces a peripheral surface of the permanent magnet. 3. The permanent magnet according to claim 1, wherein a pair of sandwiching means provided opposite both ends of the permanent magnet in the axial direction regulates the displacement of the permanent magnet in the axial direction. Rotation transmission device. 4. A length of axial displacement between one end of the permanent magnet and one end of the semi-hard magnetic body, and a length of axial displacement between the two at the other end. 4. The method according to claim 1, wherein
The rotation transmission device according to item. 5. The length of the axial displacement between the permanent magnet and the semi-hard magnetic body on the side where the second rotating shaft contacts the first rotating shaft or the permanent magnet,
The rotation transmission device according to any one of claims 1 to 3, wherein a length of the axial displacement between the two at the other end is shorter than a length of the displacement. 6. The permanent magnet according to claim 1, wherein the permanent magnet has a protrusion protruding toward the semi-hard magnetic body on at least one end in the axial direction. The rotation transmission device according to claim 1. 7. A ratio Ln / Lr of an axial length Ln of the permanent magnet to an axial length Lr of the semi-hard magnetic body is defined as:
2. The ratio is 1.00 to 1.25.
The rotation transmission device according to any one of claims 6 to 6.