JPH10318292A - Torque transmitting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a clutch from a fly wheel when the number of revolution is lowered so as to prevent the generation of overload of a prime mover at the time of starting and stopping by forming a rotary shaft and a fly wheel freely to be rotated relative to each other, and interposing a centrifugal clutch between the rotary shaft and the fly wheel so as to form a unit. SOLUTION: Since a centrifugal clutch is interposed between a rotary shaft 1 and a fly wheel 7 so as to form a unit, at the time of raising the number of revolution, driving force is gradually transmitted to the fly wheel by the centrifugal force, as the rotating speed is increased. When the number of revolution exceeds the predetermined value (prescribed number of revolution or less), the friction force of the clutch is increased so that the fly wheel and the shaft are rotated at the same rotating speed (locked). Lowering of the number of revolution is prevented by the fly wheel effect till the number of revolution becomes the predetermined number of revolution (specified umber of revolution or less). In the case where the number of revolution is less than the predetermined value, the clutch is removed from the fly wheel so as to prevent the generation of overload of a prime mover at the time of starting and a stopping the prime mover.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant-speed rotating mechanism using a flywheel to move a rotating body having a load variation at a constant rotational speed, because the flywheel is directly connected to a rotating shaft. The present invention relates to a constant-speed rotation mechanism configured to prevent overload of a prime mover at the time of startup and stoppage that occurs.

[0002]

2. Description of the Related Art Among a rotating body and a rotating mechanism used in an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile, a rotating body having a load variation such as a photosensitive drum (a rotating photosensitive body shaft). Conventionally, a flywheel is directly connected to a rotating shaft in order to stably rotate the mechanism at a constant rotational speed. The same configuration of the constant-speed rotation mechanism is also employed in a primary transfer belt shaft rotation mechanism, a paper transfer shaft rotation mechanism, and the like.

[0003]

However, in the conventional constant-speed rotating mechanism, the flywheel is directly connected to the rotating shaft, so that an overload occurs in the prime mover when starting and stopping. The present invention has been made in view of the above, and the invention of claim 1 does not directly connect the rotating shaft and the flywheel,
Since the two units are unitized via a centrifugal clutch, when the rotation speed increases, the centrifugal clutch operates by the centrifugal force as the rotation speed increases, and the driving force is gradually transmitted to the flywheel. When the rotation speed is equal to or higher than the predetermined rotation speed, the flywheel and the shaft are brought to the same rotation speed (locked state) because the frictional force of the clutch increases. In addition, at the time of deceleration, the flywheel effect prevents a sharp decrease in the rotational speed until the rotational speed falls below a certain rotational speed (below the specified rotational speed), and at the time when the rotational speed falls below that, the clutch disengages from the flywheel, An object of the present invention is to prevent an overload of a prime mover at the time of starting and stopping. According to a second aspect of the present invention, in the constant-speed rotation mechanism of the first aspect, a plurality of centrifugal clutches having different intermittent rotation speeds of the driving force are arranged, and the transmission torque is changed in a stepwise manner. Since the speed change at the time of descent is made smoother, the occurrence of overload of the prime mover at the time of starting and stopping is more effectively prevented. According to a third aspect of the present invention, in the constant-speed rotating mechanism of the first and second aspects, the contact portion of the centrifugal clutch with the flywheel is made of a rotating body (roller), so that the shock at the time of intermittent transmission torque is reduced. Prevents the overload of the prime mover when starting and stopping. According to a fourth aspect of the present invention, in the constant-speed rotation mechanism of the second aspect, the impact at the time of the intermittent transmission torque is changed by changing a friction coefficient of a member at a contact portion of the centrifugal clutch with a flywheel having a different intermittent rotation speed of the driving force. This prevents overloading of the prime mover when starting and stopping.

[0004]

Means for Solving the Problems In order to achieve the above object, an invention according to claim 1 comprises a rotating shaft driven by a prime mover, a centrifugal clutch attached to the rotating shaft, and a rotating shaft. In a rotating force transmission mechanism including a flywheel rotatably and coaxially arranged and configured to be able to contact and separate from the rotating shaft by the centrifugal clutch, a bracket that rotates integrally with the rotating shaft , A plurality of fulcrums provided at a fixed circumferential interval at the outer diameter end of the bracket, an arm whose one end is rotatably supported by each fulcrum, and each arm is urged in the inner diameter direction. And a friction member formed on an outer surface of each arm. According to a second aspect of the present invention, when the rotation speed of the rotating shaft increases, the arm gradually moves in the outer diameter direction due to centrifugal force as the rotation speed increases, thereby transmitting a driving force to the flywheel. When the number exceeds a predetermined value, the friction member of the arm locks to the flywheel and the flywheel and the shaft have the same rotation speed, and the rotation speed decreases due to the flywheel effect until the rotation speed of the rotation speed falls below a certain rotation speed The arm is detached from the flywheel when the number of rotations falls below the certain number of rotations, thereby preventing an overload of the prime mover at the time of starting and stopping. According to a third aspect of the present invention, there is provided the torque transmitting mechanism according to the first or second aspect, wherein the plurality of arms constituting the centrifugal clutch are transmitted stepwise by varying the urging force of a spring for urging the arms in an inner diameter direction. It is characterized in that the torque is changed to smoothly change the rotation speed when the rotation speed increases and decreases. The invention according to claim 4 is a rotating shaft driven by a motor, a centrifugal clutch attached to the rotating shaft, and a rotatable and coaxially disposed relative to the rotating shaft. In the rotational force transmission mechanism comprising a flywheel configured to be able to contact and separate, the centrifugal clutch,
A bracket that is integrated with the rotating shaft and rotates, a plurality of fulcrums provided at a constant circumferential interval at an outer diameter end of the bracket, and an arm one end of which is rotatably supported by each fulcrum, A roller rotatably supported at the other end of the arm. The invention of claim 5 is characterized in that the plurality of friction members or the plurality of rollers have different friction coefficients.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIGS. 1 (a) and 1 (b) are views showing the configuration of a constant-speed rotation mechanism according to a first embodiment of the present invention, wherein reference numeral 1 denotes a rotating shaft which is rotationally driven by a prime mover (not shown); A bracket that rotates integrally with the
Reference numeral 3 denotes a fulcrum provided at the outer diameter end of the bracket, 4 denotes an arm whose one end is rotatably supported by the fulcrum, 5 denotes a spring (elastic member) for urging the arm in the inner diameter direction, and 6
Is a friction member formed on the outer side surface of the arm 4, and 7 is a flywheel that is arranged so as to be rotatable relative to the rotation shaft 1 and can be connected to the rotation shaft 1 when the friction member 6 of the arm 4 comes into contact with the flywheel. . Bracket 2, fulcrum 3, arm 4,
The spring 5 and the friction member 6 constitute a centrifugal clutch. In FIG. 1 (a), when the rotating shaft 1 starts rotating, the bracket 2 integral with the rotating shaft also starts rotating, and the arm 4 on the bracket is supported by the fulcrum 3 by the rotating force.
It gradually spreads while opposing the spring 5 around. Next, when the number of rotations exceeds a certain level, the friction member 6 on the arm 4 comes into contact with the flywheel 7 as shown in FIG. The rotation and the flywheel become the same rotation speed by the time of transmission and reaching the steady rotation speed. As described above, the constant speed rotation mechanism of the present invention is unitized by interposing the centrifugal clutch between the rotating shaft 1 and the flywheel 7, so that when the rotation speed increases, the centrifugal force gradually increases as the rotation speed increases. The driving force is transmitted to the flywheel, and when the rotation speed exceeds a certain rotation speed (not more than a specified rotation speed), the frictional force of the clutch increases, so that the flywheel and the shaft have the same rotation speed (lock). Also a certain number of rotations (below the specified rotation number)
The lowering of the rotation speed is prevented by the flywheel effect until the engine speed becomes lower than that, and below that, the clutch is disengaged from the flywheel, so that the overload of the prime mover at the time of starting and stopping can be prevented.

FIG. 2 is a diagram showing a comparison of the output rotation speed variation with respect to the load variation between the embodiment of the present invention and the conventional direct connection type, using a flywheel having the same load, the same motor, and the same moment of inertia. This is an example. First, in the conventional direct connection type in which the rotating body and the flyhole are directly connected as described above, when the load F is applied at t1 to the rotating shaft in a steady rotation state, the rotation speed immediately decreases and then increases. And
Converges (returns to a steady rotation state) once the steady rotation speed is exceeded (overshoot). On the other hand, in the non-direct connection type such as the present invention, even if a load is applied to the rotating shaft 1 in the steady rotation state, the rotation speed does not immediately decrease, and after a delay of the backlash of the centrifugal clutch, the direct connection is completed. As in the case of the mold, the number of revolutions decreases, then increases, and once exceeds the steady number of revolutions (overshoot), converges (returns to the steady state of rotation). At this time, the lock by the centrifugal clutch is released, and the load becomes only the idling torque, so that the load can converge faster than that of the direct connection type. Next, in the conventional direct connection type, the load F is applied to the rotating shaft 1 in the steady rotation state at t2.
Is released, in the case of the direct connection type, the rotational speed immediately rises, then decreases, and converges after once exceeding the steady rotational speed (overshoot). On the other hand, in the present invention, as in the case of the direct connection type, the rotation speed decreases after the rotation speed increases, and once converges after exceeding the steady rotation speed (overshoot), the convergence time c at this time is Since the clutch is disengaged from the flywheel and the load is only idling torque, the rotation speed decreases and converges faster than in the direct connection type.

FIGS. 3 (a), 3 (b) and 3 (c) show an example of the configuration of a constant-speed rotating mechanism according to another embodiment of the present invention. The same parts as those in the embodiment of FIG. However, this embodiment is characterized in that the springs (elastic members) 10 and 11 for urging the four arms 4 in the inner diameter direction (non-locking direction) have different strengths. Although the shape of the bracket 2 and the number of the arms 4 are different from those in FIG. 1, the urging force of each spring may be different in a type having two arms as shown in FIG. Next, the operation of the embodiment of FIG. 3 will be described. In this embodiment, similarly to the case of FIG. 1, when the rotation shaft 1 starts rotating, each arm 4 on the bracket 2 gradually spreads in the outer diameter direction while opposing each spring 10 and 11 about the fulcrum. go. Next, when the rotation speed exceeds a certain level, as shown in FIG. 3B, the friction member 6 on the arm with the weak spring 10 comes into contact with the flywheel 7 and slips to reduce the rotational force of the rotary shaft 1. The transmission to the flywheel 7 starts gradually. Then, as the rotation speed increases, the friction member 6 on the arm 4 with the strong spring 11 comes into contact with the flywheel 7 as shown in FIG. And the rotating shaft and the flywheel have the same rotational speed until the steady rotational speed is reached. The arm 4 supported by the weak spring 10 and the other arm 4 supported by the strong spring 11 constitute centrifugal clutches having different intermittent rotation speeds, respectively, in which the urging forces of all the springs are set to be constant. As compared with the case of 1, there is provided an advantage that the transmission torque can be changed stepwise. That is, in this embodiment, since a plurality of centrifugal clutches having different intermittent rotation speeds of the driving force are arranged between the rotary shaft 1 and the flywheel 7, the transmission torque is changed stepwise, By making the speed change at the time of number rise and fall smoother, it is possible to effectively prevent the occurrence of overload of the prime mover at the time of starting and stopping.

Next, FIG. 4 is a view showing another embodiment of the constant-speed rotating mechanism according to the present invention. In this embodiment, since the contact portion of the centrifugal clutch with the flywheel is a roller 15, the transmission is performed. It is possible to relieve an impact at the time of intermittent torque and prevent an overload of the prime mover at the time of starting and stopping. Specifically, a roller 15 is rotatably supported at the tip of an arm 4 whose one end is rotatably supported by a fulcrum 3, and the arm 4 (roller 15) is supported by a spring 5 in the radial direction (the inner circumference of the flywheel). (In the direction opposite to the outer diameter direction in contact with). Roller 15
Of course, the friction coefficient is set to be equal to or more than a predetermined value so as to be lockable with the flywheel. Further, the spring 5 is bent in the outer diameter direction by the centrifugal force and
Is also the same as in the above-described embodiment.

Next, FIG. 5 is a view showing another embodiment of the constant-speed rotation mechanism according to the present invention. In this embodiment, low friction is provided on the arm with the weak spring 10 in the embodiment of FIG. The member 20 and the high friction member 21 are arranged on the arm with the strong spring 11 respectively. That is, in this embodiment, similarly to the embodiment of FIG.
And a plurality of centrifugal clutches with different intermittent rotation speeds of the driving force are arranged between them, so that the transmission torque is changed stepwise to make the speed change at the time of rotation speed increase and decrease more smooth. Thereby, at the time of starting and stopping, it is possible to effectively prevent occurrence of overload of the prime mover, while the arm having the weak spring 10 is provided with the low friction member 20 and the arm having the strong spring 11 is provided with the low friction member 20. Since the high friction member 21 is arranged, the friction coefficient of the member at the contact portion of the centrifugal clutch with the flywheel having different intermittent rotation speeds of the driving force becomes different. In addition, it is possible to effectively prevent occurrence of overload of the prime mover at the time of stoppage. In other words, the low friction member 20 is used as the friction member of the arm on the side of the weak spring 10 which operates first and starts sliding contact with the flyhole when the rotation speed of the rotary shaft 1 reaches a certain number or more. The occurrence of overload can be suppressed by reducing the contact resistance with the wheel.
Further, the rotation speed is increased, and the arm on the side of the strong spring 11 contacts the flywheel, so that the contact with the flywheel is performed stepwise and smoothly, and a smooth transition to the locked state with the flywheel is achieved. it can.

Note that the plurality of rollers in the embodiment shown in FIG. 4 may have different friction coefficients. In the above-described embodiment, an example in which two or four arms or rollers are provided in one bracket is shown. However, this is an example, and three, five,.
-The number can be arbitrarily set. However, in any case, the circumferential interval between each arm and roller must be set to be constant. In this specification, a centrifugal clutch is a bracket integrated with a rotating shaft, a plurality of arms supported by the bracket, a plurality of springs, a plurality of friction members, a plurality of rollers, etc. A unit consisting of individual arms, springs and friction members (rollers) also constitutes a centrifugal clutch.

[0011]

According to the first aspect of the present invention, the constant-speed rotating mechanism is configured so that the rotary shaft and the flywheel can be relatively rotated (in a non-direct connection state), while a centrifugal clutch is provided between the rotary shaft and the flywheel. As the unit is unitized, when the rotation speed of the drive shaft increases, the clutch operates gradually by centrifugal force as the rotation speed increases, and the drive force is transmitted to the flywheel. Then, the flywheel and the shaft are locked by the increase in the frictional force of the clutch, and the rotation speed becomes the same. At the time of deceleration, the flywheel effect prevents a sharp decrease in the rotational speed until the rotational speed falls below a certain rotational speed (below the specified rotational speed), and when the rotational speed becomes lower than that, the clutch disengages from the flywheel, thereby starting up. Further, it is possible to prevent an overload of the prime mover at the time of stoppage. According to a second aspect of the present invention, there is provided a constant-speed rotating mechanism according to the first aspect, wherein a centrifugal clutch (a weak spring and a strong spring, respectively) having different driving force intermittent rotation speeds between the rotating shaft and the flywheel. Arm), the transmission torque is changed step by step, and the speed change at the time of rotation speed rise and fall is made smoother, thereby preventing the overload of the prime mover at the start and stop. can do. The constant-speed rotating mechanism according to claim 3 is based on claim 1,
In the constant-speed rotation mechanism of No. 2, since the contact portion of the centrifugal clutch with the flywheel is made of a roller, the shock when the transmission torque is interrupted can be reduced, and the overload of the prime mover at the time of starting and stopping can be prevented. The constant-speed rotating mechanism according to claim 4 is different from the constant-speed rotating mechanism according to claim 2 in that the frictional coefficient of the member at the contact portion with the flywheel of the centrifugal clutch having different intermittent rotation speeds of the driving force is changed. The shock at the time of intermittent operation can be reduced, and the occurrence of overload of the prime mover at the time of starting and stopping can be prevented.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a configuration of a constant-speed rotation mechanism according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a comparison of output rotation speed variation with respect to load variation between the embodiment of the present invention and the conventional direct connection type.

3 (a), (b) and (c) are views showing a configuration example of a constant speed rotation mechanism according to another embodiment of the present invention.

FIG. 4 is a diagram showing another embodiment of the constant speed rotation mechanism according to the present invention.

FIG. 5 is a view showing another embodiment of the constant speed rotation mechanism according to the present invention.

[Explanation of symbols]

1 rotation axis, 2 brackets, 3 fulcrums, 4 arms,
5 spring (elastic member), 6 friction member, 7 flywheel, 10, 11 spring (elastic member), 1
5 rollers, 20 low friction members, 21 high friction members.

Claims (5)

[Claims] A rotating shaft driven by a prime mover, a centrifugal clutch attached to the rotating shaft, and a rotatable and coaxially disposed relative to the rotating shaft; The centrifugal clutch includes a bracket that rotates integrally with the rotating shaft and a fixed circumferential interval at an outer diameter end of the bracket. A plurality of fulcrums provided, an arm whose one end is rotatably supported by each fulcrum, a spring for urging each arm in the radial direction, and a friction member formed on the outer surface of each arm. A rotational force transmission mechanism characterized by having: 2. When the rotation speed of the rotary shaft increases, the arm gradually moves in the outer diameter direction due to centrifugal force as the rotation speed increases, thereby transmitting a driving force to the flywheel.
When the rotation speed exceeds a predetermined value, the friction member of the arm locks to the flywheel, and the flywheel and the shaft have the same rotation speed. 2. The motor according to claim 1, wherein the arm is detached from the flywheel when the rotational speed falls below the certain number of rotations, thereby preventing an overload of the prime mover when starting and stopping. Torque transmission mechanism. 3. The torque transmitting mechanism according to claim 1, wherein the transmission torque is gradually increased by varying the urging force of a spring for urging the plurality of arms constituting the centrifugal clutch in an inner diameter direction. A rotational force transmission mechanism characterized in that the rotational speed change at the time of increasing and decreasing the rotational speed is smoothed by changing the rotational speed. 4. A rotary shaft rotatably driven by a prime mover, a centrifugal clutch attached to the rotary shaft, and a rotatable and coaxially disposed relative to the rotary shaft. The centrifugal clutch includes a bracket that rotates integrally with the rotating shaft and a fixed circumferential interval at an outer diameter end of the bracket. A rotational force transmitting mechanism comprising: a plurality of fulcrums provided; an arm rotatably supported at one end by each fulcrum; and a roller rotatably supported at the other end of the arm. 5. The torque transmitting mechanism according to claim 1, wherein the plurality of friction members or the plurality of rollers have different friction coefficients.