JP2020150732A - Motor actuator - Google Patents

Abstract

To provide a motor actuator capable of obtaining a high driving force without increasing a motor shape and a motor rotational number, and having a small size as a whole.SOLUTION: A motor actuator 1 includes: a pair of motors 10a and 10b; a pair of power gears 11a and 11b; and a pair of transmission gears 20a and 20b. The power gear 11a and the transmission gear 20a are engaged, the power gear 11b and the transmission gear 20b are engaged, and the transmission gears 20a and 20b are also engaged. The transmission gear 20b is provided with a worm gear 22 that has a same rotational axis with the transmission gear 20b, and drives an output axis 31 by being engaged with a worm wheel 30. The motors 10a and 10b are arranged in parallel while directing both output surfaces to the same direction, and are rotated to an opposite direction.SELECTED DRAWING: Figure 4

Description

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

In this type of motor actuator, the rotation of one motor serving as a power source is decelerated by a plurality of gears to drive the output shaft. At this time, some use a worm gear and a worm wheel to increase the reduction ratio.

The configuration of the motor actuator 70 in the conventional example is shown in FIG. The motor 71 includes a rotatable shaft 72, and a worm gear 73 is press-fitted into the shaft 72, and the worm gear 73 meshes with the worm wheel 74. The rotation of the worm wheel 74 is transmitted while decelerating the output gear 75, and the required drive torque is generated in the output shaft 76.

In a motor actuator having such a structure, when it is desired to increase the output torque, 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 a drawback that the shape of the motor becomes large and the vibration increases accordingly. Further, the latter method has a drawback that the rotation speed of the motor needs to be increased by the amount that the reduction ratio is increased, and the frequency of noise is increased, which makes the user uncomfortable.

Therefore, as a method of preventing the motor from becoming large and increasing the output torque without increasing the rotation speed of the motor, it has been proposed to use a plurality of motors in combination.

The motor actuator described in Patent Document 1 has a plurality of motors, each output gear provided at each output of the motor, and a final gear directly or indirectly connected to the output gear, and depends on each output gear. The motor is controlled so that the rotational force is in the same direction and at the same speed immediately before being transmitted to the final gear. Therefore, it is said that the overall thinness and miniaturization can be achieved while finally securing the required output torque.

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

Japanese Patent No. 4989441 JP-A-2007-215303

However, in the motor actuator described in Patent Document 1, since the motor, the output gear, and the output shaft are aligned in a straight line, the shape of the motor actuator as a whole, particularly in the axial direction of the motor, becomes large. Further, since all the gears are composed of spur gears, there is no self-locking mechanism, and there is a problem that a mechanism such as a brake or a clutch is required when it is desired to keep the driven object in a predetermined position.

Further, in the actuator described in Patent Document 2, since the two worm gears are directly meshed with the worm wheel serving as the output shaft, it is difficult to arrange the motors in close proximity to each other, and the motors are placed in opposite directions with the output shafts interposed therebetween. Since it is installed, the shape of the motor in the axial direction becomes large. Further, in general, the transmission of the rotational force in the worm gear is low in efficiency and has a large variation, so that the transmission of the rotational force from the two worm gears to one worm wheel tends to cause an imbalance, which reduces the efficiency and causes inoperability. There is a problem that it may lead to stability.

Therefore, the present invention provides a motor actuator that uses two motors to increase the rotational force of the output shaft, but does not increase the shape or noise frequency of the motor actuator as a whole.

One embodiment of the present invention is
A pair of motors having rotatably held shafts, a pair of power gears fixed to the shafts one by one, a pair of transmission gears meshing with the pair of power gears, and the pair of transmission gears. A worm gear provided in one of the transmission gears and having the same rotation axis as the transmission gear, a worm wheel meshing with the worm gear, an output shaft driven by the worm wheel, and a case for accommodating these. , Equipped with
The pair of motors are arranged in parallel so that the output surfaces face in the same direction.
The pair of transmission gears are toothed together
The pair of motors are motor actuators characterized in that the rotation directions are opposite to each other.

Since the motor actuator of the present invention has a structure in which the rotational forces of the two motors are added together and then transmitted to the worm gear, and the output shaft is driven by the worm wheel meshed with the worm gear, the rotational forces of the two motors are transferred. It is possible to add them stably and to reduce the size of the actuator as a whole.

A finished product of the motor actuator 1 according to the embodiment of the present invention, (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 of FIG. 1 (a), and FIG. 2 (b) is a perspective view of FIG. 2 (a) further provided with an upper case. FIG. 2A is a perspective view in which a transmission gear, a worm gear, a worm wheel, and an output shaft are further provided in FIG. 2B, and FIG. 2B is a perspective view of a top cover. (A) is a perspective view showing the rotation direction of various gears in FIG. 3 (a), and (b) is a front view. The other embodiment of the present invention is illustrated, and is a top perspective view excluding covers covering various gears. It is a front view which showed the other structure in embodiment of this invention schematicly. It is a top view which showed the structure of the conventional motor actuator.

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

Hereinafter, embodiments of the present invention will be described exemplary with reference to the drawings.

The structure of the motor actuator according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3. 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 a motor can be installed, a side plate 41b erected from the peripheral edge of the bottom plate 41a, and an open end portion formed by the side plate 41b. The bottom plate 41a is provided with an output shaft through hole 42 for penetrating the output shaft 31.

The pair of motors 10a and 10b are installed in parallel in the lower case 41 with the output surfaces facing in the same direction, and have rotatable shafts 12a and 12b, respectively. The power gears 11a and 11b are fixed to the shafts 12a and 12b, respectively, 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 below the peripheral edge of the upper plate 43a, and an open end portion formed by the side plate 43b. The open end of the upper case 43 is incorporated 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 for penetrating the output shaft 31.

The upper surface side of the upper case 43 is also partially open, and a pair of transmission gears 20a and 20b are housed around the 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 the transmission gear bearing groove 44 and the worm gear bearing groove 45, respectively. The transmission gears 20a and 20b are meshed with the power gears 11a and 11b, respectively, and the transmission gears 20a and 20b are also meshed with each other.

One transmission gear 20b is provided with a worm gear 22 formed from the transmission gear 20b toward the counter-output direction of the motor 10b, both of which are held with the shaft 21b as a rotation shaft.

The worm wheel 30 is housed in the worm wheel housing recess 46 provided in the upper plate 43a of the upper case 43. The bearing 32 in which the output shaft 31 is press-fitted into the center of the worm wheel 30 and is 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 in FIGS. 2A and 2B). (Fig.) Is projected from the bottom surface of the motor actuator 1.

The top cover 47 is installed in the opening of the upper case 43. A transmission gear bearing convex portion 48a and a worm gear bearing convex portion 48b are provided below the upper surface 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 convex portion 49 is provided underneath to rotatably hold the output shaft 31.

The 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 in opposite directions at the same rotation speed. Therefore, 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 almost the same shape and the same characteristics and having almost the same output, and it is desirable that the motor has the same standard in design.

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

The added rotational force is transmitted to the worm wheel 30 from the worm gear 22 provided on the transmission gear 20b and having the same rotation axis. The added rotational force is output from the worm wheel 30 through the output shaft 31 to drive the driven object. Further, by using the worm gear, a self-locking mechanism can be obtained, and it is possible to prevent the driven object from operating unnecessarily.

With this configuration, the rotational forces of the pair of motors 10a and 10b are efficiently added together, using a smaller motor and without increasing the motor rotation speed, that is, the shape and noise of the motor actuator as a whole. The driving force of the motor actuator can be increased without increasing the frequency.

Further, in the above-described embodiment, the flat surface portions 13 of the motor yoke are provided above and below the pair of motors 10a and 10b, but with such a configuration, the space required is smaller than that of using a substantially cylindrical motor. Can be installed. Specifically, by forming the upper and lower surfaces of each motor into a planar shape, it is possible to easily secure an installation space for the worm gear 22 arranged on the upper portion of one of the motors, and it is possible to suppress the height of the entire actuator.

Further, in the above-described embodiment, the power gears 11a and 11b and the transmission gears 20a and 20b are all spur gears. In this way, the rotational force can be efficiently transmitted and added, and unnecessary protrusions are not generated in the output direction of the motor, which contributes to the miniaturization of the actuator as a whole. Further, when the power gears 11a and 11b and the transmission gears 20a and 20b are made into helical gears, the effect of miniaturization can be similarly obtained, and in addition, it contributes to the improvement of quietness and gear durability.

Further, in the above-described embodiment, the worm gear 22 has a structure formed from the transmission gear 20b in the counter-output direction of the motor. In this way, unnecessary protrusions are not 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 has a structure for passing 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 shaft shake when an excessive stress is applied to the output shaft can be reduced without increasing the shape of the motor actuator as a whole. ..

Further, in the above-described embodiment, the case has a housing shape for accommodating the entire motor, but the present invention is not limited to this. For example, as shown in FIG. 5, the motor is housed in a gearbox 50 accommodating all gears. It may be configured to partially accommodate. Further, although the output shaft is provided on the worm wheel, there may be several reduction gears between the worm wheel and the output shaft. In this case, the reduction ratio can be further increased. Further, although each gear and the shaft are separate members and are locked by press fitting, they may be integrally molded. Further, as shown in FIG. 6, the shapes of the motor, the power gear, and the transmission gear may be different from each other. In this case, if the rotation directions of the transmission gear 20a and the transmission gear 20b are controlled to be opposite to each other and the peripheral speeds are the same, the rotational forces are 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 the above can be carried out within a range not deviating from the gist thereof.

1 Motor actuator 10a, 10b Motor 11a, 11b Power gear 12a, 12b Shaft 13 Motor yoke flat surface 20a, 20b Transmission gear 21a, 21b Shaft 22 Warm gear 30 Warm wheel 31 Output shaft 32 Bearing 41 Lower case 41a Bottom plate 41b Side plate 42 Case side output shaft through hole 43 Upper case 43a Upper plate 43b Side plate 44 Transmission gear bearing groove 45 Warm gear bearing groove 46 Warm wheel accommodation recess 46a Upper case side output shaft through hole 47 Top cover 48a Transmission gear bearing convex part 48b Warm gear bearing convex part 49 Worm Wheel Bearing Convex 50 Gear Box 70 Conventional Motor Actuator 71 Motor 72 Shaft 73 Warm Gear 74 Warm Wheel 75 Output Gear 76 Output Shaft

Claims (6)

A pair of motors with rotatably held shafts,
A pair of power gears, one fixed to each of the shafts,
A pair of transmission gears that are in mesh with the pair of power gears,
A worm gear provided in one of the pair of transmission gears and having the same rotation axis as the transmission gear.
A worm wheel that meshes with the worm gear,
The output shaft driven by the worm wheel and
With a case to accommodate these,
The pair of motors are arranged in parallel so that the output surfaces face in the same direction.
The pair of transmission gears are toothed together
The pair of motors are characterized in that they rotate in opposite directions.
Motor actuator. The motor actuator according to claim 1, wherein the pair of motors have the same characteristics, the pair of power gears have the same shape, and the pair of transmission gears have the same shape. The motor actuator according to any one of claims 1 and 2, wherein the motor has a flat shape on a part of the outer periphery of the motor yoke. The motor actuator according to any one of claims 1 to 3, wherein the power gear and the 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 toward the counter-output direction of the motor. The motor actuator according to claim 5, wherein the output shaft is located between the pair of motors.

Images