JP2006149101A - Motor and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor of simple and inexpensive construction whose rotation can be swiftly stopped or reversed, and a control method for the motor. <P>SOLUTION: The motor (geared motor) 1 having a worm gear 2 is provided with a microswitch 8 opposed to the end face of the rotating shaft 1a of the motor 1. The state of displacement of the rotating shaft 1a of the motor 1 under overload is detected with this microswitch 8. The rotation of the motor 1 is stopped or reversed based on the resulting detection signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor and a control method thereof, and more particularly to a motor having a worm gear attached to a rotation shaft of the motor and a control method thereof.

  2. Description of the Related Art Conventionally, a geared motor in which a small DC motor and a gear reduction mechanism are integrated to obtain a large torque with low power and high rotation is known. In addition, in this type of geared motor, a worm gear is attached to the rotating shaft of the motor and a position detecting device for detecting the position of the rotating shaft in the axial direction is integrated (Japanese Patent Laid-Open No. 2000-51122). : Patent Document 1).

  The geared motor according to Patent Document 1 is applied to an automatic opening / closing device for a toilet seat / toilet lid, and the above-described position detection device quietly stops the motor when the toilet seat / toilet lid is opened / closed by the geared motor. Therefore, it is provided to suppress the impact sound of the toilet seat and toilet lid.

In addition, if the opening / closing operation of the toilet seat / toilet lid is suppressed by hand or goods while the toilet seat / toilet lid is being opened / closed by the geared motor, the geared motor will be destroyed due to overload exceeding the specified level In order to prevent this, a geared motor in which a position detection device for the motor rotation shaft is integrated to stop or reversely rotate the motor is also known.
JP 2000-51122 A

  However, the conventional motor rotation shaft position detection device uses an encoder having a Hall element and a rotor magnet, a circuit board on which a predetermined wiring pattern is formed, a coil spring and a leaf spring, and the circuit configuration and software are complicated. The cost is high, and it takes about 200 to 300 ms to stop or reversely rotate the motor.

  The present invention has been made under such a background, and an object of the present invention is to provide a motor that can quickly stop or reversely rotate with a simple and inexpensive configuration, and a control method thereof.

  In order to achieve the above object, according to the present invention, in a motor having a worm gear, a micro switch is provided so as to face an end surface of the rotating shaft of the motor.

  According to the present invention, since the micro switch is provided opposite to the end surface of the rotating shaft of the motor, it is possible to provide a motor that can quickly stop or reversely rotate with a simple and inexpensive configuration, and a control method thereof. It becomes.

[First Embodiment]
FIG. 1 is a perspective view showing a schematic configuration of a geared motor to which the motor according to the first embodiment of the present invention is applied. This geared motor is used as a motor for opening and closing the toilet lid and toilet seat.

  The geared motor is housed in a case 6, and a worm gear 2 is attached to a rotating shaft 1 a of the motor 1. That is, the worm gear 2 is composed of a worm wheel 2b having a worm 2a fixed to the rotating shaft 1a of the motor 1 and a helical gear 2ba meshed with the worm 2a.

  The worm wheel 2b is integrally formed with a helical gear 2ba and a small-diameter spur gear 2bb, and the spur gear 2bb, the first gear 3, the second gear 4, and the output gear 5 are sequentially connected. The first gear 3 is formed by coaxially and integrally forming a large-diameter spur gear 3a and a small-diameter spur gear 3b, and the second gear 4 is coaxially and integrally formed by a large-diameter spur gear 4a and a small-diameter spur gear 4b. Is formed. The large-diameter spur gear 3a of the first gear 3 is meshed with the spur gear 2bb of the worm wheel 2b, and the small-diameter spur gear 3b of the first gear 3 is engaged with the large-diameter spur gear 4a of the second gear 4. The small-diameter spur gear 4 b of the second gear 4 is meshed with the output gear 5.

  In other words, a reduction gear train is connected to the rotating shaft 1a of the motor 1, and the high-speed rotation / small torque output of the motor 1 is converted into the low-speed rotation / large torque output and output. The motor 1 is constituted by a DC motor (including a stepping motor), and is actually mounted on a motor mounting plate 7 fixed to the case 6 as shown in FIG.

  A micro switch 8 is disposed at a position facing the end surface (cut surface) of the rotating shaft 1 a of the motor 1. That is, the microswitch 8 is fixed to the extending portion 7a of the motor mounting plate 7, and the pushbutton actuator 8a of the microswitch 8 is in contact with the tip of the rotating shaft 1a of the motor 1 or forms a minute gap. Thus, the microswitch 8 is provided.

  As is well known, the micro switch 8 presses the actuator 8a, so that the movable contact instantaneously moves to the fixed contact by an internal snap action mechanism (configured by a tension spring and a compression spring: not shown) to open and close the circuit. It operates and is easier to handle than position detectors such as encoders, and can detect the position quickly and inexpensively.

  This micro switch 8 detects the overload state of the motor 1 by detecting the position of the rotary shaft 1a displaced by the thrust of the worm gear 2 fixed to the rotary shaft 1a of the motor 1, and the motor is detected by detecting the overload. 1 is provided to prevent the motor 1 and the gear train from being destroyed by stopping the rotation of the motor 1 or rotating it in the reverse direction.

  That is, when the teeth of the worm 2a are twisted in the direction as shown in FIG. 3, as shown in FIG. 3A, the motor 1 is rotated clockwise as seen from the direction of the worm gear 2 from the motor 1 side. In this case, the teeth of the worm 2a act to rotate the worm wheel 2b counterclockwise. As a reaction, the worm 2a (the rotating shaft 1a) has a thrust in a direction away from the motor 1, that is, in a direction approaching the microswitch 8. Will work. On the contrary, as shown in FIG. 3B, when the motor 1 rotates counterclockwise, the teeth of the worm 2a act to rotate the worm wheel 2b to the right, and the worm 2a (rotation) acts as a counter-action. A thrust in the direction approaching the motor 1, that is, the direction away from the microswitch 8 is applied to the shaft 1a).

  The amount of displacement (thrust) of the rotating shaft 1a is the clearance of the bearing of the motor 1, the clearance between the teeth of the worm 2a and the teeth of the worm wheel 2b, the bearing of the gear shaft 12 of the worm wheel 2b (pressed into the worm wheel 2b). Is determined by the clearance (not shown), and the torque is constant while the motor 1 is rotating at a constant speed. Therefore, the displacement (thrust) of the rotating shaft 1a is constant, and the rotating shaft 1a moves from a predetermined position. Disappear.

  However, when the motor 1 is rotating at a constant speed (that is, when the toilet lid / toilet seat is opened / closed), for example, when the user presses the toilet lid / toilet seat and the motor 1 (worm wheel 2b) is overloaded. The displacement amount (thrust) of the rotating shaft 1a increases, and the rotating shaft 1a pushes the actuator 8a of the microswitch 8 or moves away from the actuator 8a.

  In the present embodiment, the micro switch 8 is a single contact type (make contact type), and as shown in FIG. 3A, when the motor 1 is rotating forward (when the toilet lid / toilet seat is opened, or (When closed), the thrust of the rotating shaft 1a acts in the direction of the micro switch 8, and when the motor is rotating at a constant speed, the rotating shaft 1a does not contact the actuator 8a of the micro switch 8 and there is a small separation distance (micro) The switch 8 is in an open (OFF) state. When an overload is applied, the rotary shaft 1a presses the actuator 8a of the microswitch 8 so that the microswitch 8 is in a short (ON) state. And the deployment position is set.

  However, according to the contact method (open / close switching contact, break contact, make contact, etc.), the micro switch 8 is short-circuited during constant motor rotation (when not pressed) and open when overloaded (pressed). It is also possible to make it.

  As shown in FIG. 3B, the motor 1 is overloaded so that the thrust of the rotating shaft 1a works away from the micro switch 8 when the motor 1 is reversely rotated (when the toilet lid / toilet seat is closed or opened). In such a case, it is necessary to slide the rotating shaft 1a in a rotating state on the actuator 8a of the micro switch 8 for a long time when rotating at a constant motor speed, and the sliding resistance of the sliding portion is required. Although there is a problem in dynamics and it is not practical, although not shown in the present embodiment, the rotating shaft 1a is extended on the left side of the motor 1 in FIG. 1, and another microswitch is provided at the opposite position. (The same applies to other embodiments).

  In other words, the case where the toilet lid and the toilet seat are opened and closed by a complicated and expensive method of using one micro switch and adding a mechanism for reversing the rotation of the output gear 5 while keeping the rotation direction of the motor 1 constant. In this embodiment, instead of dealing with both overload conditions, a simple and inexpensive method is provided in which a microswitch is separately provided in the vicinity of both ends of the rotating shaft 1a to rotate the motor 1 forward / reversely. Thus, both overloading states in both cases of opening and closing the toilet lid / toilet seat are supported.

[Second Embodiment]
In the first embodiment, the actuator 8a of the microswitch 8 is directly pressed by the rotating shaft 1a of the motor 1. However, when the actuator 8a of the micro switch 8 is directly pressed by the rotating shaft 1a of the motor 1, the pressing stroke and pressing force for causing the micro switch 8 to snap action, the thrust and the displacement amount of the rotating shaft 1a of the motor 1, etc. In consideration of the relationship, it is necessary to properly adjust the clearance between the rotating shaft 1a of the motor 1 and the actuator 8a of the micro switch 8, which makes assembly work difficult.

  Therefore, in the second embodiment, as shown in FIG. 4, a leaf spring 17 is provided between the rotating shaft 1 a of the motor 1 and the actuator 8 a of the microswitch 8.

  In FIG. 4, the motor 1 is fixed to the motor mounting plate 9 with screws, and the motor mounting plate 9 is fixed to the lower resin case 10b joined to the upper resin case 10a with screws 11.

  A worm 2a is fixed to the output shaft 1a of the motor 1 by press-fitting, bonding, screwing or the like. A worm gear 2 is configured by meshing with the worm 2a a large-diameter helical gear 2ba (not visible in the worm 2a in FIG. 4) of the worm wheel 2b supported by the gear shaft 12. Further, the small-diameter spur gear 2bb of the worm wheel 2b is engaged with the output gear 5 supported by the output gear shaft 13. Bearing parts 12a and 12b for press-fitting and fixing the gear shaft 12 and bearing parts 13a and 13b for inserting the output gear shaft 13 are formed in the upper and lower resin cases 10a and 10b, respectively. The rotation of the output gear shaft 13 is transmitted to a toilet lid and toilet seat opening / closing mechanism (not shown).

  The circuit board 14 is attached to a mounting plate 15, and the mounting plate 15 is fixed to the lower resin case 10 b with screws 16. On the circuit board 14, a micro switch 8 is attached by soldering or the like at a position facing the tip of the rotating shaft 1 a of the motor 1, and a “U” -shaped leaf spring 17 is attached.

  The output terminal of the microswitch 8 is connected to a control circuit that stops or reversely rotates the motor 1 based on the output signal (overload detection signal) of the microswitch 8, and this control circuit is connected to the circuit board 14. Formed on top.

  As shown in FIG. 5, the leaf spring 17 is attached to the circuit board 14 and the mounting plate 15 by caulking with a rivet 18 so as to urge the push button type actuator 8a of the micro switch 8 in the pressing direction. It has been. Note that the urging force of the leaf spring 17 with respect to the actuator 8a of the micro switch 8 is set in a range where the micro switch 8 does not cause a snap action operation.

  Thus, by biasing the actuator 8a of the micro switch 8 in advance by the leaf spring 17, the movable contact of the micro switch 8 can be moved even if the thrust of the worm gear 2 is small. Further, the movable contact of the micro switch 8 can be moved even if the displacement amount of the worm gear 2, that is, the rotating shaft 1a is small by the thickness of the plate spring 17.

  In other words, the microswitch 8 can be operated without strictly managing the clearance between the rotating shaft 1a of the motor 1 and the actuator 8a of the microswitch 8, and the assembling work becomes easy. Further, the load and stroke amount for detecting the overload state can be reduced by the micro switch 8, and the motor 1 and the gear can be quickly stopped by detecting the overload state and quickly stopping or reversely rotating. It becomes possible to prevent the destruction of the columns.

[Third Embodiment]
In the second embodiment shown in FIG. 4, in the motor 1, the microswitch 8 is mounted on mounting plates 9 and 15 fixed to the lower resin case 10b, respectively, and a gear shaft 12 and an output gear shaft 13 are mounted. Are supported by bearing portions 12a and 12b and bearing portions 13a and 13b formed in the upper and lower resin cases 10a and 10b, respectively. Therefore, the meshing accuracy of the gears and the coaxiality of the gear shaft 12 and the output gear shaft 13 depend on the dimensional accuracy of the upper and lower resin cases 10a and 10b.

  However, considering shrinkage and deformation due to resin molding, it is difficult to improve the meshing accuracy of the gears and the accuracy of the coaxiality of the gear shaft 12 and the output gear shaft 13, and the gears and the gear shaft bearing portions 12a, 12b, 13a and 13b increase the loss load, increasing the power consumption of the motor 1 and shortening its service life. Further, when the motor output or the reduction ratio is increased in order to obtain a high output, when a great radial load is applied to the output gear shaft 13, the bearing portions 12a, 12b formed on the resin cases 10a, 10b, In 12b, 13a, and 13b, there exists a problem in the intensity | strength as a bearing part. Furthermore, in order to properly operate the microswitch 8 without depending on the dimensional accuracy of the resin cases 10a and 10b, it is necessary to adjust the positional relationship between the rotating shaft 1a of the motor 1 and the microswitch 8, and assembling workability Becomes worse.

  Therefore, in the third embodiment, as shown in FIG. 6, the motor 1, the gear shaft 12, the output gear shaft 13, the circuit board 14 and the like are integrally attached to a metal main chassis (base plate) 19. ing.

  That is, the metal main chassis 19 is formed with a mounting hole for the motor 1, a press-fitting hole for the gear shaft 12, an insertion hole for the output gear shaft 13, a mounting hole for the leaf spring 17 and the circuit board 14, and the like. Manufactured by. The motor 1 is fixed to the main chassis 19 with screws 20a and 20b, a speed reduction gear train is incorporated, the leaf spring 17 and the circuit board 14 are attached and integrated with rivets 18, and both ends of the gear shaft 12 are connected to the resin cases 10a and 10b. The entire geared motor is covered with the upper and lower resin cases 10a and 10b by press-fitting into the bearing portions 21a and 21b.

  The size and shape of the main chassis 19 are determined by the design of each mechanism, but depending on whether the bearing for the output gear shaft 13 is attached to the main chassis 19 or the diameter of the output gear 5 is increased. It is also possible to change the shape (see FIG. 7).

  In this way, the motor 1, gear reduction mechanism, microswitch 8, leaf spring 17, and circuit board 14 are integrally mounted on the metal main chassis 19, so that the coaxiality of the bearings of the gear shaft 12 and the output gear shaft 13 is achieved. Thus, the loss load can be reduced, the power consumption of the motor 1 can be reduced, and the life can be extended. In addition, since the bearing portion is formed on the metal main chassis 19 and the strength of the bearing portion is increased, the motor output and the reduction ratio can be increased, and the load in the radial direction can be increased. Further, the microswitch 8 can be properly operated without strictly defining the positional relationship between the rotating shaft 1a of the motor 1 and the microswitch 8, and the assembly workability is improved.

[Fourth Embodiment]
As in the second and third embodiments, if the leaf spring 17 is only provided, the micro switch 8 is appropriately set due to an error in the mounting position of the leaf spring 17, an error in spring pressure, insufficient thrust of the worm gear 2, and the like. There is a risk that it cannot be operated.

  Therefore, in the fourth embodiment, as shown in FIG. 8, a screw hole is formed at the position of the main chassis 19 with which the plate spring 17 contacts, and the adjusting screw 22 is screwed into this screw hole, whereby the plate spring 17. The fulcrum, the point of action and the bending angle are displaced. This displacement increases the biasing force of the leaf spring 17 against the actuator 8a of the microswitch 8, and the microswitch 8 can be reliably operated even if the thrust of the worm gear 2 is small during overload.

  In addition, this invention is not limited to said embodiment, For example, it is also possible to apply to motors other than a geared motor. Further, the present invention can be applied to a motor in which a load in the axial direction is applied by a mechanism other than the worm gear, or can be applied to a drive motor other than a drive for opening / closing the toilet lid / toilet seat.

1 is a perspective view showing a schematic configuration of a geared motor to which a motor according to a first embodiment of the present invention is applied. It is a figure which shows the attachment state of the motor in the geared motor of FIG. It is a figure for demonstrating the thrust of a worm gear. It is sectional drawing which shows schematic structure of the geared motor to which the motor based on the 2nd Embodiment of this invention is applied (plate spring addition). It is a figure which shows the attachment state of the leaf | plate spring in the geared motor of FIG. It is sectional drawing which shows schematic structure of the geared motor to which the motor based on the 3rd Embodiment of this invention is applied (metallic main chassis). It is a figure which shows the modification of metal main chassis. It is a figure which shows the attachment state of the leaf | plate spring in the geared motor which concerns on the 4th Embodiment of this invention (adjustment screw addition).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Motor, 2 ... Worm gear, 2a ... Worm, 2b ... Worm wheel, 3 ... 1st gear, 4 ... 2nd gear, 5 ... Output gear, 8 ... Microswitch, 8a ... Microswitch actuator, 17 ... Leaf spring , 19 ... Main chassis (made of metal), 22 ... Adjustment screw

Claims (13)

In a motor having a worm gear,
A motor characterized in that a micro switch is provided opposite to an end face of the rotating shaft of the motor.   The motor according to claim 1, wherein the output terminal of the microswitch is connected to a control circuit that stops or reverses the motor based on an output signal of the microswitch.   The motor according to claim 2, wherein the microswitch is attached to a circuit board on which the control circuit is formed.   4. The micro switch according to claim 1, wherein the micro switch is in an OFF state when the actuator of the micro switch is not pressed by the rotating shaft of the motor, and is turned ON when the micro switch is pressed. Motor.   The motor according to any one of claims 1 to 4, wherein the microswitch is individually provided on both ends of the rotating shaft of the motor.   The motor according to claim 1, wherein the worm gear is connected to a reduction gear train.   The motor according to claim 1, further comprising a spring member that applies a biasing force to the actuator of the microswitch.   The motor according to claim 7, wherein the spring member is configured by a leaf spring.   The motor according to claim 7, further comprising an adjustment member that adjusts the urging force by the spring member.   The motor according to claim 9, wherein the motor, the worm gear, the reduction gear train, the micro switch, the circuit board, the spring member, and the adjustment member are integrally attached to a metal base plate.   The motor according to claim 10, wherein the metal base plate is housed in a resin case.   The motor according to any one of claims 1 to 11, wherein the motor is a DC motor used to open and close a toilet lid and a toilet seat. In a method for controlling a motor having a worm gear,
A motor control method comprising a control step of stopping or reversing the motor on the basis of an output signal of a microswitch provided to face an end surface of a rotation shaft of the motor.

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