JP2004080843A - Motor with limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor equipped with a limiter which can break the current supply to itself with simple mechanical structure. <P>SOLUTION: A first switching-on terminal 40 follows the rotation of an inner housing 31, and a part on the rotation trajectory of this first switching-on terminal 40 is provided with a second switching-on terminal 42, and this second switching-on terminal 42 is fixed to an outer housing 30 on fixing side. In such a motor 1, the power supply to a coil 33 is required in stationary state, so the first switching-on terminal 40 of the inner housing 31 is kept abutted on the second switching-on terminal 42 on fixing side, and at this point, the inner housing 31 keeps its static state. As against this, the inner housing 31 rotates in the opposite direction to the rotational direction of a rotary shaft 3 by the cooperation between a coil 33 and a magnet 32, the instant the rotation of the rotary shaft 3 is stopped compulsively by some reason. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention particularly relates to a motor with a limiter for adapting to a field where a small precision motor is required in a copier, a game machine, an AV machine, or the like.
[0002]
[Prior art]
Conventionally, a geared motor described in JP-A-6-200988 is a motor in which a gear box is screwed to a motor body, and a planetary gear mechanism is provided in this gear housing, and the planetary gear mechanism is used. In the output shaft, a large reduction ratio and a large output torque can be generated. If the rotation of the output shaft is forcibly stopped for some reason, each gear in the planetary gear mechanism generates an instantaneous impact force at the time of stoppage, which causes the gears to deform. Or the teeth of the gear may be broken, and in some circumstances, the coil of the motor itself may burn out. Therefore, in order to appropriately prevent such situations, a slip torque mechanism may be employed in the planetary gear mechanism of the motor, or an excessive current that is continuously supplied to the motor may be detected, and the power supply to the coil may be interrupted by a fuse or the like. Needed a current limiter.
[0003]
[Problems to be solved by the invention]
In a conventional motor, a control circuit for interrupting a current supplied to a coil when an output shaft is overloaded is separately provided. However, it is necessary to set a large current difference between the current in the steady state and the current in the abnormal state (overcurrent) in order to prevent the power supply to the motor from being stopped in the steady state. When the difference is increased, the load on the motor is increased at the time of abnormality. On the other hand, if the current difference is reduced, the motor may malfunction. As described above, the current limiter applied to the conventional motor currently depends on a control circuit that needs to consider an appropriate current difference.
[0004]
It is an object of the present invention, in particular, to provide a motor with a limiter that cuts off power supply to the motor with a simple mechanical structure.
[0005]
[Means for Solving the Problems]
A motor with a limiter according to the present invention is a motor having a configuration in which a rotation shaft rotates at a predetermined rotation speed by cooperation of a coil and a magnet, while accommodating the coil and the magnet, and the rotation shaft protruding from an end. A movable inner housing that is rotatable in a circumferential direction about a rotation axis, a fixed outer housing that surrounds the inner housing, and an integral housing that is protruded from the inner housing and electrically connected to the coil. A first energizing terminal provided on the outer housing and electrically connected to an external power source, and positioned at a part of a rotation locus of the first energizing terminal and in contact with the first energizing terminal; And a flexible second energizing terminal.
[0006]
This motor with a limiter has a double housing structure in which the inner housing rotates in the circumferential direction within the outer housing on the fixed side, and such a special housing structure mechanically configures the current limiter. That is, in the present invention, the first energizing terminal is caused to follow the rotation of the inner housing, and the second energizing terminal is provided on a part of the rotation locus of the first energizing terminal, and the second energizing terminal is fixed. Side to the outer housing. In such a motor, power supply to the coil is required in a steady state, so that the first energizing terminal of the inner housing is kept in contact with the second energizing terminal on the fixed side. , The inner housing remains stationary. On the other hand, at the moment when the rotation of the rotating shaft is forcibly stopped for some reason, the inner housing rotates in the direction opposite to the rotating direction of the rotating shaft due to the cooperation of the coil and the magnet. Then, when the inner housing rotates in the circumferential direction, the first conductive terminal of the inner housing moves in a direction away from the second conductive terminal of the outer housing, and at that moment, over-feeding to the coil is cut off. As described above, since the motor itself has the mechanical current limiter, a limiter that does not depend on the circuit configuration can be achieved with a simple configuration, and the handleability of the motor itself is improved.
[0007]
The first energizing terminal is provided integrally with a terminal support that protrudes in the axial direction of the rotation shaft from a bottom plate provided at a rear end of the inner housing, and the second energizing terminal is provided at a rear end of the outer housing. It is preferable to have an external power supply connecting portion projecting from the bottom plate provided in the portion in the axial direction of the rotating shaft, and a lead portion extending in a cantilevered manner from the external power supply connecting portion to the first energizing terminal. Such a configuration takes into consideration the workability of assembling the motor.
[0008]
In addition, a terminal receiving recess for receiving the second energizing terminal is provided on the bottom surface of the outer housing, and the terminal receiving recess is formed with an opening extending in the circumferential direction to insert the terminal support, The lead portion is formed of an elastic material and is housed in the terminal housing recess. The tip of the lead portion has a V-shaped bent contact portion and is fixed to the inner surface side of the terminal support portion. It is preferable that a recessed engaging portion into which the contact portion is fitted is provided at the tip of the one energizing terminal. By providing elasticity to the lead portion, when the contact portion is resiliently pressed against the first energizing terminal, the stationary state of the inner housing can be appropriately maintained in the steady state. Moreover, since the V-shaped contact portion of the lead portion fits into the concave engagement portion of the first energizing terminal, the inner housing can be more reliably held in a steady state.
[0009]
In addition, a stopper portion is provided on the rear surface of the front plate provided at the front end of the outer housing, and the stopper protrudes in the axial direction of the rotating shaft.The front plate provided at the front end of the inner housing extends in the circumferential direction. It is preferable that a rotation regulating groove into which the stopper portion is fitted is provided. At the moment when the rotation of the rotating shaft is forcibly stopped for some reason or when an excessive load is applied to the rotating shaft, the inner housing starts rotating in the circumferential direction. At this time, when the rotation restricting groove moves with the rotation of the inner housing and the stopper abuts against the end of the rotation restricting groove, the rotation of the inner housing is forcibly stopped at a predetermined position. That is, even after the power supply to the coil is cut off, the inner housing, which tries to keep rotating by the inertial force, can be stopped at an appropriate position.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a motor with a limiter according to the present invention will be described in detail with reference to the drawings.
[0011]
As shown in FIG. 1, the motor 1 with a limiter includes a motor body A composed of a small-sized cored motor, and a gear box C containing a planetary gear mechanism B for predetermined reduction. A gear box C is fixed to the motor main body A via screws 2, and the rotating shaft 3 of the motor main body A protrudes into the gear box C. A drive gear 4 is provided on the rotating shaft 3, and the drive gear 4 is meshed with a transmission gear 7 composed of upper and lower two stages, and the transmission gear 7 is supported by a support shaft erected from a bottom surface 6 of a gear box C. 8 rotatably supported. The upper stage 7a of the transmission gear 7 is connected to the planetary gear mechanism B.
[0012]
The planetary gear mechanism B has a first-stage sun shaft 9 arranged on the axis L of the rotating shaft 3. The sun shaft 9 is rotatably supported by a support shaft 11 erected from the bottom surface 6 and extending on the axis L of the rotating shaft 3. On the lower side of the sun shaft 9, a connection gear 9a meshing with the upper portion 7a of the transmission gear 7 is integrally formed. On the upper side of the sun shaft 9, a sun gear 9b is integrally formed. , Three planetary gears 13 mesh with each other.
[0013]
Each of the planetary gears 13 is rotatably mounted on the carrier 14 and is meshed with a lower fixed ring gear 15 fixed to the inner surface of the gear box C. The carrier 14 is rotatably supported by a shaft 9 c provided at the tip of the sun shaft 9. A second stage sun shaft 16 located on the axis L is formed integrally with the carrier 14, and a sun gear 16 a is integrally formed with the second stage sun shaft 16. , Three planetary gears 18 mesh with each other. Each planetary gear 18 is rotatably mounted on a carrier 19 and is meshed with an upper fixed ring gear 20 fixed to the inner surface of the gear box C.
[0014]
The carrier 19 is integrally provided with a shaft mounting portion 22 extending in the direction of the axis L, and the base end of the output shaft 23 whose front end is exposed from the gear box C is fixed to the shaft mounting portion 22. The output shaft 23 is rotatably supported by a shaft 16 b provided at the tip of the sun shaft 16. Further, the output shaft 23 is supported by a radial bearing 24 fixed to the cover 21 of the gear box C. Therefore, when the rotation shaft 3 of the motor body A rotates at a predetermined rotation speed, the output shaft 23 rotates at a low speed by the planetary gear mechanism B having a predetermined reduction ratio.
[0015]
Here, in order to mechanically configure the current limiter, the motor main body A has a double housing structure in which the inner housing 31 can rotate in the circumferential direction within the outer housing 30 on the fixed side. A magnet 32 having N and S poles is fixed to an inner wall surface of the inner housing 31, and a rotor 35 having a coil 33 wound around an iron core 34 is accommodated inside the inner housing 31. The rotating shaft 3 supported by a bearing 36 is fixed to the center of the rotor 35, and the tip of the rotating shaft 3 extends to penetrate the front end portion of the inner housing 31. Further, a commutator 37 is fixed to the rear end of the rotating shaft 3 in the inner housing 31, and a pair of brushes 38 slidably contact the commutator 37, and the brushes 38 and the coil 37 33 is supplied. Further, the distal end side of each brush 38 made of a leaf spring is in sliding contact with the surface of the commutator 37, and the proximal end side of each brush 38 is fixed to the bottom plate 39 of the inner housing 31.
[0016]
As shown in FIGS. 1 to 3, the motor main body A has an outer housing 30 made of metal such as steel and having a circular cross section. The outer housing 30 rotates around the rotation shaft 3 in the circumferential direction. A freely movable inner housing 31 is accommodated. A first metal terminal 40 connected to the brush 38 and extending in the direction of the axis L is integrally provided with a resin bottom plate 39 provided in the inner housing 31. One end is connected to the base end of the brush 38, and the other end protrudes from the bottom plate 39 in the direction of the axis L. A plate-shaped terminal supporting portion 41 protruding in the direction of the axis L is formed integrally with a bottom plate 39 provided at the rear end of the inner housing 31. The leading end of one of the conducting terminals 40 is buried. Note that the number of the terminal support portions 41 and the number of the first energizing terminals 40 correspond to the number of the brushes 38.
[0017]
On the other hand, as shown in FIGS. 2 to 4, the outer housing 30 is provided with two second energizing terminals 42 made of metal. Each second power supply terminal 42 projects from the bottom plate 43 of the outer housing 30 in the direction of the axis L to facilitate connection with an external power supply, and is orthogonal to the external power supply connection 44. It has a plate-shaped seating portion 45 and a lead portion 46 that extends substantially linearly from the external power supply connection portion 44 to the first power supply terminal 40 in a cantilevered manner. The lead portion 46 is formed of an elastic material, and a contact portion 46a bent in a V-shape is provided at the tip thereof. The second energizing terminal 42 is fixed to the bottom plate 43 by eyelets 48 after aligning the insertion hole 45a of the seat 45 with the insertion hole 43a of the bottom plate 43 (see FIG. 1). The resin bottom plate 43 is fixed at the rear end of the outer housing 30 by the claw pieces 30b.
[0018]
The current-carrying terminal 42 having such a shape is advantageous in assembling work, but is preferably not exposed to the outside as much as possible in consideration of handling of the motor 1 itself. Therefore, each second energizing terminal 42 is accommodated in a terminal accommodating recess 50 provided on the bottom plate 43 of the outer housing 30. In the terminal accommodating concave portion 50, the lead portion 46 and the external power supply connecting portion 44 of the second energizing terminal 42 are accommodated in a state of being set up in the direction of the axis L, and the seat 45 is in a state of being orthogonal to the direction of the axis L. Housed in. Then, only the external power supply connection portion 44 protrudes from the bottom plate 43 in a state where the second power supply terminal 42 is housed in the terminal housing recess 50. Further, an opening 51 is formed in the terminal accommodating concave portion 50 on the contact portion 46a side, and the terminal support portion 41 is inserted into the opening 51 from inside. The opening 51 draws an arc centered on the axis L, and allows the terminal support 41 to move in the circumferential direction.
[0019]
In this manner, the second energizing terminal 42 is fixed to the bottom plate 43 of the outer housing 30, and the first energizing terminal 40 is rotatable in the circumferential direction along the opening 51. Therefore, the contact portion 46a of the second energizing terminal 42 is located at a part on the rotation locus of the movable first energizing terminal 40, and can freely contact the first energizing terminal 40 (see FIG. 5). ).
[0020]
Further, as shown in FIG. 5, a concave engaging portion for fitting a contact portion 46a formed by bending into a V-shape is fitted to the tip of the first energizing terminal 40 fixed to the terminal supporting portion 41. A part 53 is provided. Accordingly, since the lead portion 46 has elasticity, the contact portion 46a is resiliently pressed against the first energizing terminal 40, and in the steady state (at the time of normal use of the motor 1), The stationary state can be maintained properly. In addition, since the V-shaped contact portion 46a fits into the concave locking portion 53 of the first energizing terminal 40, the inner housing 31 can be more reliably held in a steady state.
[0021]
Further, as shown in FIGS. 3 and 6, a cylindrical stopper 55 projecting in the direction of the axis L is provided on the back surface of the front plate 30 a provided at the front end of the outer housing 30. On the other hand, the front plate 31a provided at the front end of the inner housing 31 is provided with a rotation regulating groove 56 in which the stopper 55 is fitted so as to extend in the circumferential direction. Therefore, when the rotation regulating groove 56 moves with the rotation of the inner housing 31 and the stopper portion 55 abuts against one end of the rotation regulating groove 56, the rotation of the inner housing 31 is forcibly stopped at that position.
[0022]
Therefore, even when the inner housing 31 rotates in the abnormal state, the contact portion 46a of the second energizing terminal 42 separates from the first energizing terminal 40, and tries to rotate by the inertial force even after the power supply to the coil 33 is cut off. The inner housing 31 can be forcibly stopped at an appropriate position. The two stopper portions 55 provided opposite to each other are provided with screw holes 57 for screwing the screws 2 used for connecting the motor body A and the gear box C, so that space efficiency is improved. I'm trying.
[0023]
Next, the operation of the motor 1 will be briefly described based on the configuration of the motor 1 described above.
[0024]
First, when a current is supplied from the external power supply connection portion 44 of the second power supply terminal 42 in a state where the first power supply terminal 40 and the second power supply terminal 42 are electrically connected (see FIG. 4). Then, the power supply to the coil 33 is started, and the output shaft 23 continues to rotate. In such a steady state, the state where the first energizing terminal 40 of the inner housing 31 is in contact with the contact portion 46a of the second energizing terminal 42 on the fixed side is maintained. At this time, the inner housing 31 is stationary. Continue to maintain state.
[0025]
However, at the moment when an abnormal situation occurs in which the rotation of the output shaft 23 is forcibly stopped for some reason, the terminal support portion 41 of the inner housing 31 is rotated by the cooperation of the coil 33 and the magnet 32. In the direction R opposite to the rotation direction F (see FIG. 7). Thus, the first conductive terminal 40 of the inner housing 31 moves in a direction away from the contact portion 46a of the second conductive terminal 42. At this time, over-feeding to the coil 33 is cut off, and burning of the motor body A is avoided. In addition, as shown in FIG. 8, when the rotating shaft 3 is rotating in the direction of arrow P, the terminal support 41 of the inner housing 31 moves in the direction of arrow Q.
[0026]
As described above, since the motor 1 itself has a mechanical current limiter, a limiter that does not depend on the circuit configuration can be achieved with a simple configuration, and the handleability of the motor 1 itself is improved. When the motor 1 is returned, the terminal support portion 41 is picked up with a jig or the like and returned to the original position (see FIG. 4).
[0027]
The motor 1 according to the present invention is not limited to the embodiment described above. For example, instead of the second energizing terminal 42 formed of a leaf spring, a contact portion provided at the tip of the compression coil spring may be elastically pressed against the first energizing terminal 40. In this case, the urging force of the compression coil spring may be changed by using an adjustment screw.
[0028]
【The invention's effect】
Since the motor with limiter according to the present invention is configured as described above, the following effects are obtained. That is, in a motor having a configuration in which a rotating shaft rotates at a predetermined rotation speed by cooperation of a coil and a magnet, the motor accommodates the coil and the magnet, and the rotating shaft protrudes from an end portion to rotate around the rotating shaft. An inner housing on the movable side rotatable in the direction, an outer housing on the fixed side surrounding the inner housing, a first energizing terminal that is provided integrally with and protrudes from the inner housing, and that is electrically connected to the coil; A second energizing terminal that is provided on the outer housing and is electrically connected to an external power source and that is located on a part of the rotation path of the first energizing terminal and that can freely contact the first energizing terminal; With this configuration, power supply to the motor can be cut off with a simple mechanical structure.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a motor with a limiter according to an embodiment of the present invention, taken along line II of FIG.
FIG. 2 is an exploded perspective view of a motor main body in the motor according to the present invention.
FIG. 3 is an exploded perspective view of a motor main body in the motor according to the present invention.
FIG. 4 is a bottom view of the motor according to the present invention.
FIG. 5 is an enlarged sectional view of a main part showing a state in which the second energizing terminal is in contact with the first energizing terminal.
FIG. 6 is a front view of a motor body of the motor according to the present invention.
FIG. 7 is a bottom view showing a state where the first energizing terminal is separated from the second energizing terminal when an abnormality occurs during normal rotation of the motor.
FIG. 8 is a bottom view showing a state where the first energizing terminal is separated from the second energizing terminal when an abnormality occurs during the reverse rotation of the motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Motor with a limiter, 3 ... Rotating shaft, 30 ... Outer housing, 30a ... Front plate of outer housing, 31 ... Inner housing, 31a ... Front plate of inner housing, 32 ... Magnet, 33 ... Coil, 39 ... Inner housing Bottom plate, 40: first energizing terminal, 41: terminal support portion, 42: second energizing terminal, 43: bottom plate of outer housing, 44: external power supply connection portion, 46: lead portion, 46a: contact portion, 50 ... Terminal accommodating concave portion, 51: opening portion, 53: locking portion, 55: stopper portion, 56: rotation regulating groove, L: axis.

Claims (4)

In a motor having a configuration in which a rotation shaft rotates at a predetermined rotation speed by cooperation of a coil and a magnet,
While accommodating the coil and the magnet, the rotating shaft protrudes from an end portion, a movable inner housing that is rotatable in a circumferential direction around the rotating shaft,
A fixed outer housing surrounding the inner housing;
A first energizing terminal that is provided integrally with and protrudes from the inner housing and is electrically connected to the coil;
A second power supply terminal provided on the outer housing and electrically connected to an external power supply, and located on a part of the rotation path of the first power supply terminal and capable of abutting on the first power supply terminal. A motor with a limiter, comprising: The first energizing terminal is provided integrally with a terminal support that protrudes in the axial direction of the rotation shaft from a bottom plate provided at a rear end of the inner housing,
The second energizing terminal is
An external power supply connection portion projecting in the axial direction of the rotation shaft from a bottom plate provided at a rear end of the outer housing;
The motor with a limiter according to claim 1, further comprising a lead portion extending in a cantilevered support state from the external power supply connection portion to the first power supply terminal. A terminal accommodating recess for accommodating the second energizing terminal is provided on the bottom surface of the outer housing, and an opening is formed in the terminal accommodating recess to extend in the circumferential direction and to insert the terminal support. And
The lead portion is formed of an elastic material and is accommodated in the terminal accommodating recess, and a tip of the lead portion has a V-shaped contact portion,
The motor with a limiter according to claim 2, wherein a concave engaging portion into which the contact portion is fitted is provided at a tip of the first energizing terminal fixed to an inner surface of the terminal supporting portion. . On the back surface of the front plate provided at the front end of the outer housing, provided is a stopper portion projecting in the axial direction of the rotation shaft,
The front plate provided at a front end portion of the inner housing is provided with a rotation regulating groove which extends in a circumferential direction and into which the stopper portion is fitted. Motor with limiter according to item.

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