JPH10311453A - Motor-driven actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate strain of stopper parts, and accurately regulate a rotary range of an output shaft by arranging an engaging part in a gear fitted to and installed on the output shaft, and arranging the stopper parts in a gear casing so as to regulate the rotary range of the output shaft by locking the engaging part so as to be locked and released. SOLUTION: When an electric motor 4 is started, its torque is transmitted to an output shaft 12 through speed reduction gears 7 to 11 from a main gear 6. The output shaft 12 is rotated in one direction against a spring 15, and a valve interlocking with the output shaft 12 is put in a valve opening condition. In this case, an engaging part 17 is protrusively arranged on an under surface of the gear 11 in a gear casing 1, on the one hand, stopper parts 18a and 18b are protrusively arranged in a lower case 2 of the gear casing 1. When the engaging part 17 is locked on one of the stopper parts 18a and 18b at rotating time of the gear 11, rotation of the output shaft 12 is stopped. These stopper parts 18a and 18b do not strain at locking time of the engaging part 17 since a height is low, a rotary range of the output shaft 12 can be accurately regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric actuator for controlling the opening and closing of a valve provided, for example, in a fluid flow path of an air conditioner, and more particularly to an electric actuator having improved means for restricting rotation of a valve control system output shaft. It is.

[0002]

2. Description of the Related Art FIG. 6 is a longitudinal sectional view showing a conventional electric actuator, and FIG. 7 is a view taken along line AA of FIG. In FIG. 6, reference numeral 1 denotes a gear casing of an electric actuator. The gear casing 1 includes a lower case 2 having a bottomed dish shape, and a cover 3 that covers an open end of an upper surface of the lower case 2.
And consists of

Reference numeral 4 denotes an electric motor mounted on the cover 3. A driving gear 6 composed of a small-diameter pinion gear is fitted on a rotating shaft 5 of the electric motor 4, and a plurality of reduction gears are mounted on the driving gear 6. The output shaft 12 of the valve opening / closing control system is linked via 7, 8, 9, 10, 11.

The gears 6, 7, 8, 9, 10, 11
Are meshed and arranged in the gear casing 1 in a state where they are pivotally supported over the lower case 2 and the cover 3. Among the gears 6, 7, 8, 9, 10, 11 other than the main driving gear 6 and the final reduction gear 11, other gears 7,
8, 9, 10 are coaxially provided with small-diameter gears 7a, 8
a, 9a and 10a.

A first reduction gear 7 meshes with the main driving gear 6, a second reduction gear 8 meshes with the small diameter gear 7a, and a third reduction gear 9 meshes with the small diameter gear 8a. 9a, a fourth reduction gear 10 is provided with a small-diameter gear 10a.
The final reduction gears 11 mesh with each other, and this reduction gear 11 is fitted on the output shaft 12.

Reference numeral 13 denotes a one-way clutch incorporated in the third reduction gear 9. This one-way clutch 13 transmits a one-way torque from the motor rotation shaft 5 to the output shaft 12, and outputs the one-way clutch. The shaft 12 is allowed to rotate in the other direction. The clutch may be incorporated in any gear, and the clutch may not be provided.

Reference numeral 14 denotes a flange member mounted and fixed on the upper portion of the output shaft 12, and reference numeral 15 denotes a coiled spring interposed between the flange member 14 and the cover 3.
The spring 15 urges the output shaft 12 in a direction opposite to the rotation direction due to the transmission of the rotational force from the electric motor 4.

In the above, the output shaft 12 is provided on the cover 3.
A pair of stoppers 16a and 16b are formed to rise to a height substantially equal to the height of the flange member 14 along the axis. The stoppers 16a and 16b have an angle of about 90 degrees about the output shaft 12 as shown in FIG. Are arranged at intervals. On the other hand, on the side surface of the flange member 14, a flat arm-shaped engaging portion 1 protruding between the stopper portions 16a and 16b is provided.
4a is protruded, and when the output shaft 12 rotates, the engaging portion 1
The rotation range of the output shaft 12 is restricted by locking the 4a to one of the stopper portions 16a and 16b.

Next, the operation will be described. Electric motor 4
Is started by energization, the rotating shaft 5 of the electric motor 4
The rotational force of the main gear 6 to the reduction gears 7, 8, 9, 10,
By being transmitted to the output shaft 12 via 11, the output shaft 12 rotates in one direction against the spring 15.
Then, when the engaging portion 14a of the flange member 14 that rotates synchronously with the output shaft 12 is locked to one of the stopper portions 16a,
When the output shaft 12 stops, a valve (not shown) linked to the output shaft 12 is opened. This open state is maintained as long as the electric motor 4 is energized.

When the energization of the electric motor 4 is interrupted in such a valve-open state, the output shaft 12 is returned and rotated by the urging force of the spring 15, and the engaging portion 14a is turned into the other stopper portion 1.
When the output shaft 12 is stopped by being locked at 6b, the valve is closed.

[0011]

Since the conventional electric actuator is configured as described above, the engaging portion 14a of the flange member 14 which rotates synchronously with the output shaft 12 serves as a rotation restricting means for the output shaft 12. The stoppers 16a and 16b raised from the cover 3 to almost the same height as the flange member 14 are distorted when the engaging portion 14a is locked, and the distortion causes the stoppers 16a and 16b to be locked.
As a result, the opening / closing control of the valve linked to the output shaft 12 is not accurately performed, the valve opening / closing accuracy is impaired, or an unnecessary force is required for the electric motor 4,
In addition, there is another problem that the distortion of the stopper portions 16a and 16b gradually increases and the stopper function is completely lost. This problem is caused by the fact that the springs 15 are interposed between the cover 3 and the flange member 14, so that the stoppers 16a and 16b must be lengthened in the height direction. 16a, 1
When the length of the stopper 6b is increased, the stopper 16
There are also problems such as an increase in the molding cost and weight of the a and 16b and an increase in the center of gravity of the electric actuator.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can eliminate the distortion of a stopper for restricting the rotation range of the output shaft, thereby accurately restricting the rotation range of the output shaft. It is another object of the present invention to provide an electric actuator that can reduce the center of gravity of the electric actuator. Another object of the present invention is to provide an electric actuator capable of accurately performing opening / closing control of a valve linked to an output shaft and improving valve opening / closing accuracy. In addition, the present invention
An object of the present invention is to provide an electric actuator that can easily form a stopper and does not increase the weight due to the stopper. A further object of the present invention is to provide an electric actuator which can easily form a stopper portion and can sufficiently secure its strength.

[0013]

According to a first aspect of the present invention, there is provided an electric actuator comprising: an electric motor; a gear casing to which the electric motor is attached; a gear group housed and arranged in the gear casing; An electric actuator having an output shaft rotatably driven by the electric motor via a gear group, wherein an engaging portion is provided on a gear fitted to the output shaft, and inside the gear casing,
A stopper is provided for locking the engaging portion so as to be disengageable and restricting a rotation range of the output shaft.

In the electric actuator according to the second aspect of the present invention, a valve for opening and closing the fluid flow path or switching the fluid flow path is linked to the output shaft, and a stopper portion is provided at a fully closed position and / or a fully open position of the valve. It is provided.

In the electric actuator according to the third aspect of the present invention, the stopper portion is formed by partially cutting and bending the wall of the gear casing inward.

According to a fourth aspect of the present invention, there is provided the electric actuator, wherein the engagement portion of the output shaft is locked by the thick end surface of the stopper portion.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a longitudinal sectional view showing an electric actuator according to Embodiment 1 of the present invention, FIG. 2 is a sectional view of a main part extracted from FIG. 1, and FIGS. 3 (a) and 3 (b) show a relation of an output shaft system. FIG. 8 is an explanatory diagram showing the relationship between the joining portion and the stopper portion, and the same or corresponding portions as in FIGS. In the figure, reference numeral 17 denotes an engaging portion provided on a part of the gear 11 fitted to the output shaft 12, and the engaging portion 17 comprises an engaging pin projecting from the lower surface of the gear 11. The engaging portion 17 is formed of any one of an engaging pin fitted to a perforated portion of the gear 11, an engaging pin adhered to the lower surface of the gear 11, and an engaging pin protruding integrally with the lower surface of the gear 11. It may be.

A pair of stoppers 18a and 18b are provided inside the gear casing 1 to engage and disengage the engaging portions 17 with each other.
8b protrudes from the inner bottom wall of the lower case 2 of the gear casing 1 and, as shown in FIGS. 3 (a) and 3 (b),
It is located at an interval of about a 90-degree rotation angle about the output shaft 12. Even in the case of the stopper portions 18a and 18b, any of the stopper portion 18a, 18b, which is fitted to the perforated portion of the lower case 2, adhered to the lower case 2, or integrally formed with the lower case 2, etc. It may be.

As described above, the engaging portion 17 protrudes from the lower surface of the gear 11 housed in the gear casing 1, and the stopper portions 18 a and 18 b are provided on the inner bottom wall of the lower case 2 of the gear casing 1. Due to the protrusion, stopper portions 18a and 18 for locking the engaging portion 17 in a small height range between the lower surface of the gear 11 and the inner bottom wall of the lower case 2 are provided.
b does not become distorted when the engaging portion 17 is locked, unlike a conventional stopper portion rising up from the cover 3 to the flange member 14. Therefore, the rotation range of the output shaft 12 can be accurately regulated, and a valve (not shown) for opening and closing the fluid flow path of the air conditioner is linked to the output shaft 12 so that the valve is fully opened. By disposing the stopper portions 18a and 18b at the position and the fully closed position, the opening / closing accuracy of the valve is improved. Gear casing 1
Since the engaging portion 17 and the stopper portions 18a and 18b are located between the lower surface of the gear 11 and the lower case 2 in the inside, the center of gravity is lower than in the prior art, and the stability of the electric actuator is reduced. improves.

Embodiment 2 FIG. 4 is a perspective view showing a main part of a lower case according to Embodiment 2 of the present invention. In the second embodiment, the bottom plate of the lower case 2 is cut and bent to stand up, so that the stoppers 18a, 1
8b. The stoppers 18a, 18b thus formed are a part of the bottom plate of the lower case 2, and therefore, the stoppers 18a, 18b are formed.
8b does not increase the weight of the lower case 2, that is, the weight of the entire electric actuator. In addition, it is not necessary to form the stopper portions 18a and 18b as separate members, and therefore, material saving can be achieved.

Embodiment 3 FIG. 5 is a configuration explanatory view showing a stopper portion according to Embodiment 3 of the present invention in relation to an engagement portion. In the third embodiment, the engaging portions 17 are engaged with the thick (plate thickness) end surfaces of the plate-like stopper portions 18a and 18b raised from the bottom plate of the lower case 2. As described above, the stopper portions 18a and 18b for locking the engaging portion 17 with the thick end surface can obtain sufficient strength without any risk of distortion when the engaging portion 1 is locked.

In each of the above-described embodiments, the engagement portion 17 is provided on the lower surface of the gear, and the lower case 2 constituting the gear casing is provided.
Although the case where stopper portions 18a and 18b are provided on the gear is described, the engaging portion 17 is provided on the upper surface of the gear, and the stopper portion is provided on the cover 3 constituting the gear casing, or
A part of the gear 11 is missing and the side of the missing part is used as the engaging part 17 or the engaging part 17 is provided on the side of the gear.
The stopper portion with which is engaged is a pillar portion provided on the lower case 2. Alternatively, a long hole is formed around the output shaft in which the gear 11 is attached to the lower case 2 or the cover 3, and a stopper pin that engages with the long hole is provided in the gear, and both ends of the long hole are engaged with the stopper pin. The same operation and effect as those of the above-described embodiments can be obtained also as the joint.

[0023]

As described above, according to the first aspect of the present invention, the stopper portion for regulating the rotation range of the output shaft on which the gear for inputting the torque of the electric motor is fitted is provided. And an engaging portion for engaging the stopper portion is provided on the gear, and the engaging portion is engaged with the stopper portion near the gear in the gear casing. As in the case of the stopper portion rising high from the gear casing as in the above, the stopper portion is not distorted when the engagement portion is locked, so that the rotation range of the output shaft can be accurately regulated, By locating the engaging portion and the stopper portion in the gear casing, there is an effect that the center of gravity of the electric actuator is lowered and stability is obtained.

According to the second aspect of the present invention, the valve for opening and closing the fluid flow path or the fluid flow path switching means is linked to the output shaft in the first aspect, and the stopper is provided at the fully closed position and / or the fully open position of the valve. Since the unit is provided, there is an effect that the opening / closing control of the valve can be accurately performed, and the valve opening / closing accuracy can be improved.

According to the third aspect of the present invention, since the stopper portion is formed by partially cutting and bending the wall portion of the gear casing inward, the stopper portion can be formed easily and the gear casing can be formed easily. Since the stopper portion formed by the wall portion does not require a separate member, there is an effect that the weight is not increased and the material can be saved.

According to the fourth aspect of the present invention, since the engagement portion of the output shaft is locked by the thick end surface of the stopper portion, it is possible to obtain an electric actuator which can sufficiently secure the strength of the stopper portion. There is an effect that can be done.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an electric actuator according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view in which main parts of FIG. 1 are extracted.

FIGS. 3 (a) and 3 (b) are explanatory diagrams showing a relationship between an engagement portion and a stopper portion of an output shaft system.

FIG. 4 is a perspective view showing a main part of a lower case according to a second embodiment of the present invention.

FIG. 5 is a configuration explanatory view showing a stopper portion according to a third embodiment of the present invention in relation to an engagement portion.

FIG. 6 is a longitudinal sectional view showing a conventional electric actuator.

FIG. 7 is a view taken along line AA of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gear casing 4 Electric motor 6-11 Gear 12 Output shaft 17 Engagement part 18a, 18b Stopper part

Claims (4)

[Claims] 1. An electric motor, a gear casing to which the electric motor is attached, a gear group housed and arranged in the gear casing, and an output shaft rotatably driven by the electric motor via the gear group. In the electric actuator, the engagement portion is provided on the gear fitted to the output shaft, and the engagement portion is detachably locked in the gear casing to rotate the output shaft. An electric actuator having a stopper for regulating a range. 2. A fluid passage opening / closing or fluid passage switching valve is linked to an output shaft, and a stopper portion is provided at a fully closed position and / or a fully opened position of the valve. Item 2. The electric actuator according to Item 1. 3. The electric motor according to claim 1, wherein the stopper portion is formed by partially cutting and bending a wall portion of the gear casing toward the inside of the gear casing. Actuator. 4. The device according to claim 1, wherein the stopper is configured to lock the engaging portion of the output shaft with the thick end surface. Electric actuator.