JP7311879B2 - motor actuator - Google Patents

Description

The present invention relates to a motor actuator, for example for operating a miniature massage machine.

This type of motor actuator drives an output shaft by decelerating the rotation of a single motor, which is a power source, using a plurality of gears. At this time, some use a worm gear and a worm wheel to increase the reduction ratio.

FIG. 7 shows the configuration of a conventional motor actuator 70. As shown in FIG. The motor 71 has a rotatable shaft 72 , a worm gear 73 is press-fitted on the shaft 72 , and the worm gear 73 meshes with a worm wheel 74 . Rotation of the worm wheel 74 is transmitted through the output gear 75 while being decelerated, and the required driving torque is generated in the output shaft 76 .

In order to increase the output torque of the motor actuator having such a structure, a method of increasing the rotational force of the motor itself and a method of increasing the reduction ratio between gears are adopted. However, the former method has the disadvantage that the shape of the motor becomes large and the vibration increases accordingly. Further, in the latter method, it is necessary to increase the number of revolutions of the motor to compensate for the increase in the speed reduction ratio.

Therefore, as a method of preventing an increase in the size of the motor and increasing the output torque without increasing the number of rotations of the motor, a proposal has been made to use a combination of a plurality of motors.

The motor actuator described in Patent Document 1 has a plurality of motors, each output gear provided for each output of the motor, and a final gear directly or indirectly connected to the output gear. The motor is controlled so that the rotational force is in the same direction and at the same speed just before it reaches the final gear. Therefore, it is said that it is possible to reduce the overall thickness and size while securing the final required output torque.

In the actuator described in Patent Document 2, one rotary shaft is formed by meshing worm gears provided on the output shafts of two motors with one worm wheel, which is the final output (rotary shaft). are driven and controlled by two motors. Therefore, it is said that it can be used stably without increasing the size of the actuator and gear, and that brake control can be easily performed by using one of them for braking.

Japanese Patent No. 4989441 Japanese Patent Application Laid-Open No. 2007-215303

However, in the motor actuator disclosed in Patent Document 1, the motor, the output gear, and the output shaft are arranged in a straight line. In addition, since the gears are all spur gears, there is no self-locking mechanism, so there is a problem that a mechanism such as a brake or a clutch is required to keep the driven object in a predetermined position.

In addition, in the actuator disclosed in Patent Document 2, the two worm gears are directly meshed with the worm wheel serving as the output shaft. Since it is installed, the shape in the axial direction of the motor becomes large. In general, worm gears transmit rotational force with low efficiency and large fluctuations, so an imbalance is likely to occur in the transmission of rotational force from two worm gears to one worm wheel, which reduces efficiency and impairs operation. There is a problem that it may lead to stability.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a motor actuator that uses two motors to increase the rotational force of the output shaft without increasing the overall shape and noise frequency of the motor actuator.

One embodiment of the present invention is
a pair of motors having shafts held rotatably; a pair of power gears fixed to the shafts; a pair of transmission gears meshing with the pair of power gears; a worm gear provided only on one of the transmission gears and having the same rotation axis as that of the one transmission gear; a worm wheel meshing with the worm gear; and an output shaft driven by the worm wheel; and a case for accommodating them,
The pair of motors are arranged in parallel so that their output surfaces face the same direction,
The pair of transmission gears are meshed with each other,
The pair of motors rotate in opposite directions ,
One of the transmission gears transmits the drive torque of one of the motors directly to the worm gear, and the other transmission gear transmits the drive torque of the other motor to the worm gear via the one of the transmission gears. , the combined drive torque of the pair of motors is transmitted to the worm gear;
A motor actuator characterized by:

The motor actuator of the present invention has a structure in which the rotational forces of the two motors are added together before being transmitted to the worm gear, and the worm wheel meshing with the worm gear drives the output shaft. The sum can be stably added, and the miniaturization of the actuator as a whole can be realized.

1 is a finished product of a motor actuator 1 according to an embodiment of the present invention, in which (a) is a top perspective view and (b) is a bottom perspective view. (a) is a perspective view showing only the lower case, the motor, and the power gear in FIG. 1(a), and (b) is a perspective view showing the upper case in FIG. 2(a). (a) is a perspective view in which a transmission gear, a worm gear, a worm wheel, and an output shaft are further provided in FIG. 2(b), and (b) is a perspective view of a top cover. (a) is a perspective view showing rotation directions of various gears in FIG. 3 (a), and (b) is a front view. Fig. 10 is a top perspective view of another embodiment of the present invention with the cover covering the various gears removed; It is the front view which showed roughly the other structure in embodiment of this invention. FIG. 3 is a plan view showing the structure of a conventional motor actuator;

In this specification, in FIGS. 2(a) and 4(a), the direction in which the shaft of the motor protrudes is called the "output direction", and the opposite direction is called the "counter-output direction". is called the "output surface". Further, in FIG. 4B, the upward direction is simply called "upward direction", and the opposite direction is simply called "downward direction".

An embodiment of the present invention will be exemplified below based on the drawings.

A structure of a motor actuator according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. The motor actuator 1 includes a pair of motors 10a and 10b, a pair of power gears 11a and 11b, a pair of transmission gears 20a and 20b, a worm gear 22, a worm wheel 30, an output shaft 31, a lower case 41 and an upper case 43. and an upper cover 47 .

The lower case 41 has a bottom plate 41a molded so that the motor can be installed, side plates 41b erected from the periphery of the bottom plate 41a, and an open end formed by the side plates 41b. The bottom plate 41a is provided with an output shaft through hole 42 for passing the output shaft 31 therethrough.

The pair of motors 10a and 10b are installed in parallel in the lower case 41 with their output surfaces directed in the same direction, and have rotatable shafts 12a and 12b, respectively. Power gears 11a and 11b are fixed to shafts 12a and 12b by a method such as press fitting. The power gears 11a and 11b have the same shape.

The upper case 43 has an upper plate 43a, a side plate 43b provided downward from the peripheral edge of the upper plate 43a, and an open end formed by the side plate 43b. The open end of the upper case 43 is assembled into the open end of the lower case 41 to form a housing having a predetermined internal space. The upper plate 43a is provided with an output shaft through hole 46a through which the output shaft 31 is passed.

The upper surface side of the upper case 43 is also partially opened, and a pair of transmission gears 20a and 20b are housed around shafts 21a and 21b, respectively. The transmission gears 20a and 20b have the same shape. The shafts 21a and 21b are fixed to the transmission gears 20a and 20b by a method such as press fitting, and are held in transmission gear bearing grooves 44 and worm gear bearing grooves 45, respectively. Transmission gears 20a and 20b mesh with power gears 11a and 11b, respectively, and transmission gears 20a and 20b also mesh.

One of the transmission gears 20b is provided with a worm gear 22 formed in a direction opposite to the output of the motor 10b from the transmission gear 20b, and both are held with a shaft 21b as a rotation axis.

The worm wheel 30 is housed in a worm wheel housing recess 46 provided in the upper plate 43 a of the upper case 43 . The output shaft 31 is press-fitted into the center of the worm wheel 30, and bearings 32 are press-fitted into the output shaft through-hole 46a of the upper case 43 and the output shaft through-hole 42 of the lower case 41 (not shown in FIGS. 2A and 2B). ) through the bottom of the motor actuator 1 .

An upper cover 47 is installed in the opening of the upper case 43 . A transmission gear bearing projection 48a and a worm gear bearing projection 48b are provided below the top cover 47, and are inserted into the transmission gear bearing groove 44 and the worm gear bearing groove 45, respectively, to sandwich the shafts 21a and 21b. Further, a worm wheel bearing projection 49 is provided below to hold the output shaft 31 rotatably.

Operation of the motor actuator 1 will be described with reference to FIG. The two motors 10a and 10b have the same characteristics and rotate at the same speed in opposite directions. Accordingly, the power gears 11a and 11b also rotate in opposite directions. The motor having the same characteristics means a motor having a stator and a rotor having substantially the same shape and characteristics and having substantially the same output.

The transmission gears 20a and 20b meshing with the power gears 11a and 11b also rotate in opposite directions. At this time, the pair of transmission gears 20a and 20b have the same peripheral speed, and since the transmission gears 20a and 20b are also meshing with each other, the rotational forces of the two motors are added together.

The combined rotational force is transmitted to the worm wheel 30 from the worm gear 22 provided in the transmission gear 20b and having the same rotational axis. The combined rotational force is output from the worm wheel 30 through the output shaft 31 to drive the driven object. Also, the use of a worm gear provides a self-locking mechanism to prevent unnecessary movement of the driven object.

With this configuration, the rotational forces of the pair of motors 10a and 10b are efficiently added together, and a smaller motor can be used without increasing the number of motor rotations. The driving force of the motor actuator can be increased without increasing the frequency.

In the above-described embodiment, the flat portions 13 of the motor yokes are provided above and below the pair of motors 10a and 10b. can be installed. Specifically, by making the upper and lower surfaces of each motor flat, it is possible to easily secure an installation space for the worm gear 22 arranged above one of the motors, and to reduce the height of the entire actuator.

Further, in the above-described embodiment, the power gears 11a, 11b and the transmission gears 20a, 20b are all spur gears. In this way, the torque can be efficiently transmitted and added, and an unnecessary projecting portion is not formed in the output direction of the motor, which contributes to miniaturization of the actuator as a whole. Also, when the power gears 11a, 11b and the transmission gears 20a, 20b are helical gears, the effect of downsizing is similarly obtained, and in addition, it contributes to the improvement of silence and gear durability.

Further, in the above-described embodiment, the worm gear 22 is configured to extend from the transmission gear 20b toward the counter-output direction of the motor. With this configuration, no unnecessary projecting portion is generated in the output direction of the motor, which contributes to miniaturization of the actuator as a whole.

Further, in the above-described embodiment, the output shaft 31 is configured to pass between the pair of motors 10a and 10b. In this way, the distance between the bearings of the output shaft can be increased, so that the vibration of the output shaft when an excessive stress is applied to the output shaft can be reduced without enlarging the shape of the motor actuator as a whole. .

Further, in the above-described embodiment, the case has a housing shape that accommodates the entire motor, but the present invention is not limited to this. For example, as shown in FIG. It may be configured to partially accommodate. Also, although the output shaft is provided on the worm wheel, there may be several stages of reduction gears between the worm wheel and the output shaft. In this case, the speed reduction ratio can be further increased. Further, although each gear and shaft are separate members and are engaged by press fitting, they may be integrally molded. Alternatively, as shown in FIG. 6, the motor, power gear, and transmission gear may have different shapes. In this case, if the rotational directions of the transmission gears 20a and 20b are opposite to each other and the peripheral speeds are controlled to be the same, the rotational forces can be added in the same manner as shown in FIG. 4(b). can be done.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above, and various modifications other than those described above can be made without departing from the gist of the present invention.

Reference Signs List 1 motor actuator 10a, 10b motor 11a, 11b power gear 12a, 12b shaft 13 plane portion of motor yoke 20a, 20b transmission gear 21a, 21b shaft 22 worm gear 30 worm wheel 31 output shaft 32 bearing 41 lower case 41a bottom plate 41b side plate 42 lower Case-side output shaft through-hole 43 Upper case 43a Upper plate 43b Side plate 44 Transmission gear bearing groove 45 Worm gear bearing groove 46 Worm wheel housing recess 46a Upper case-side output shaft through-hole 47 Top cover 48a Transmission gear bearing projection 48b Worm gear bearing projection 49 worm wheel bearing convex portion 50 gear box 70 conventional motor actuator 71 motor 72 shaft 73 worm gear 74 worm wheel 75 output gear 76 output shaft

Claims (7)

a pair of motors having shafts rotatably held;
a pair of power gears, one each secured to the shaft;
a pair of transmission gears meshing with the pair of power gears;
a worm gear provided only on one of the pair of transmission gears and having the same rotational axis as the one transmission gear;
a worm wheel meshing with the worm gear;
an output shaft driven by the worm wheel;
and a case for accommodating them,
The pair of motors are arranged in parallel so that their output surfaces face the same direction,
The pair of transmission gears are meshed with each other,
The pair of motors rotate in opposite directions ,
One of the transmission gears transmits the drive torque of one of the motors directly to the worm gear, and the other transmission gear transmits the drive torque of the other motor to the worm gear via the one of the transmission gears. , the combined drive torque of the pair of motors is transmitted to the worm gear;
characterized by
motor actuator. 2. A motor actuator according to claim 1, wherein said pair of motors have the same characteristics, said pair of power gears have the same shape, and said pair of transmission gears have the same shape. 3. The motor actuator according to claim 1, wherein a part of the outer periphery of the motor yoke of the motor is planar. A motor actuator according to any one of claims 1 to 3, wherein said power gear and said transmission gear are spur gears or helical gears. The motor actuator according to any one of claims 1 to 4, wherein the worm gear is formed from the transmission gear in a counter-output direction of the motor. 6. The motor actuator according to claim 5, wherein the pair of motors are arranged such that the respective motor yokes are arranged in parallel with a gap therebetween, and the output shaft is provided in the gap . The worm gear and the worm wheel are arranged above the pair of motors arranged in parallel, the output shaft extends downward from above the pair of motors through the gap, and the case 7. The motor actuator according to claim 6, wherein the power is output to the outside from the bottom plate of the motor actuator.

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