JPH1118403A - Motor-driven actuator and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a motor-driven actuator perform accurately the proper initial-position recognizing operation of its output shaft by providing such stoppers respectively in its final gear and the inside of its case that they can be stopped by each other in the rotational direction of its output shaft, and that the initial position of its output shaft can be recognized via stopping. SOLUTION: In the initial-position recognizing operation of a motor-driven actuator 1, when the command of the initial-position recognizing operation of an output shaft 11 is sent from a controller 20 to a stepping motor 2, the output shaft 11 is rotated until a first stopper 12 of a fourth gear 8 is stopped by one of two second stoppers 13. For example, when the signal having a pulse number corresponding to the rotation of the output shaft 11 rotating by 100 deg. is sent to the stepping motor 2. The first stopper 12 is rotated necessarily until it and the second stopper 13 are engaged to stop by each other, irrespective of the rotational position of the output shaft 11. After the stopping, similar to sending pulse signals to the stepping motor 2 for returning the output shaft 11 by 5 deg., the initial position of the output shaft 11 is recognized accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric actuator having a stepping motor as a drive source and a control method therefor, and more particularly to an electric actuator suitable for controlling the opening / closing or opening of various dampers in a vehicle air conditioner. And its control method.

[0002]

2. Description of the Related Art In an air conditioner for a vehicle, for example, various rotary dampers (doors) are often used to control a temperature control state and a destination of temperature-controlled air. An electric actuator is often used for control.

The electric actuator has a driving source
In many cases, a stepping motor capable of controlling the amount of rotation by the number of pulses is used. Generally, in an electric actuator using such a drive source, it is necessary to recognize an initial position, that is, an origin position for control, in order to control a rotation amount and a control position of an output shaft. .

Heretofore, as a means for recognizing the initial position of the output shaft, there has been known a method in which a predetermined pattern provided on a substrate and a brush provided on the output shaft are used.

[0005]

However, the conventional initial position recognition method as described above requires a substrate, a brush and the like, so that the product cost of the electric actuator is high and the number of parts is small. However, there is a problem that the assemblability increases and the assemblability is poor.

An object of the present invention is to provide an electric actuator suitable for use in a vehicle air conditioner, which has a small number of parts, is low in cost, and has good assemblability, focusing on such problems. is there.

Another object of the present invention is to provide an electric actuator capable of performing an accurate initial position recognition operation of an output shaft without causing inconvenience, and to provide an optimal control method of the electric actuator.

[0008]

In order to solve the above problems, an electric actuator according to the present invention comprises a stepping motor, a case to which the stepping motor is attached, an output shaft projecting from the case, 2 provided between the stepping motor and the output shaft
An electric actuator comprising at least one gear and a final gear connected to the output shaft, wherein the final gear and the inside of the case can be locked to each other in the rotation direction of the output shaft. And a stopper capable of recognizing the initial position of the output shaft via the locking is provided.

The locking position of the two stoppers is a position having a certain margin angle α ° with respect to the normal operation range of the output shaft,
That is, it is preferable to set the output shaft at a position of the normal operation range + α °. α ° is preferably set in the range of 1 to 20 °, for example, may be set to about 5 °.

In addition, the control method of the electric actuator according to the present invention uses the electric actuator in which the stopper locking position is set to the position of the normal operation range of the output shaft + α °, and once the output shaft is Rotate to the stop position of the stopper, and then return the output shaft by α °,
The method comprises controlling the stepping motor.

Such an electric actuator and its control method are particularly suitable for use in controlling various rotary dampers in a vehicle air conditioner.

In the above-mentioned electric actuator, since a substrate, a brush and the like used in the conventional apparatus are not required, the number of parts is reduced and the product cost is reduced accordingly. In addition to reducing the number of parts,
Each of the stoppers can be formed integrally with the final gear, formed integrally with the inner surface of the case, or attached in advance, so that the electric actuator can be assembled very easily.

In adopting the locking structure using the two stoppers, the locking position is set within the normal operation range of the output shaft.
For example, if the output shaft is set at the initial position itself, the lock torque by the stepping motor may be applied not only at the time of the initial position recognition operation but also at the time of the normal operation, which may adversely affect the life of each part.

However, as described above, the locking position of both stoppers is set to the position of the normal operation range of the output shaft + α °, and the output shaft is temporarily moved to the normal operation range + α ° as the initial position recognition operation.
If it is rotated to both stopper locking positions and immediately returned by α °, the initial position recognition operation
That is, the locking torque of the stepping motor is not applied except when the stoppers are locked, which can contribute to a longer life of each part. In addition, since the initial position of the output shaft can be recognized by returning a preset α ° from the mechanical locking position by both stoppers, the initial position can be accurately recognized with extremely high accuracy and excellent reproducibility. Is done.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 to 3
1 shows an electric actuator according to one embodiment of the present invention. 1 and 2, the electric actuator 1
Has a stepping motor 2 as a drive source, and the stepping motor 2 is mounted on the outer surface of the case 4 so that the output shaft 3 extends into the case 4. The case 4 includes an upper case 4a and a lower case 4b,
In this embodiment, the first gear 5 and the second gear 5 are provided in the case 4.
A gear group including four gears, a gear 6, a third gear 7, and a fourth gear 8, is housed. The first gear 5 is fixed to the output shaft 3 of the stepping motor 2. The second gear 6
The third gear 7 is rotatably supported on the support shaft 10 on a support shaft 9 protruding from the inner surface of the lower case 4b.

The rotational driving force from the output shaft 3 of the stepping motor 2 is transmitted from the first gear 5 to the second gear 6, the third gear 7, and the fourth gear 8 as the final gear in this order.
The fourth gear 8 is connected to the output shaft 11 of the electric actuator 1.
And these are configured to rotate integrally. The output shaft 11 protrudes from the case 4 and is connected to another member whose rotation amount is to be controlled. When the electric actuator 1 is used in a vehicle air conditioner, for example, various types of rotary dampers (not shown)
Connected to.

On the lower surface in FIGS. 1 and 2 of the fourth gear 8 as the final gear, a first stopper 12 is provided integrally with the gear 8, and in the present embodiment, the first stopper 12 As shown in FIG. 3, the planar shape is formed in a sector shape. A second stopper 13 is provided inside the case 4, more specifically, on the inner surface (bottom surface) of the lower case 4 b.
The second stopper 13 may be formed integrally with the lower case 4b, or may be formed as a separate part and attached to the lower case 4b in advance. In the present embodiment, the second stopper 13
Are formed as a pair of stoppers, and the first stopper 12 of the fourth gear 8 can rotate within a range of the angle θ therebetween. Then, at the rotation end, the first stopper 12 and the second stopper 13 are locked with each other. That is, the first stopper 12 and the second stopper 13 are connected to the output shaft 1.
In the one rotation direction, they can be locked to each other.

The movable angle θ of the first stopper 12 between the pair of stoppers of the second stopper 13 is the output shaft 1
A certain fixed allowance 2 for one normal operation range
The angle is obtained by adding α, that is, the angle of the output shaft 11 (the normal operation range β) + 2α °. For example, when the normal operation range β of the output shaft 11 is 90 °, α = 5 °
And θ is set to 100 °. In this case, the angle α ° (= 5 °) from the position where the second stopper 13 is locked to one of the pair of stoppers.
Is the initial position (origin position on control) of the output shaft 11, and the range of θ−2α ° (= 90 °) from the initial position to the engagement position with the other stopper is the normal position of the output shaft 11. The operating range is β.

The operation of recognizing the initial position of the electric actuator 1 is performed as follows. When an initial position recognition operation command of the output shaft 11 is sent from the control device 20 to the stepping motor 2, the output shaft 11 is moved to the first stopper 12 of the fourth gear 8.
Rotate until it is locked by one of the second stoppers 13. For example, in the above example, the stepping motor 2
When the signal of the number of pulses corresponding to the rotation of the output shaft 11 by 100 ° is sent, the first stopper 12 and the second stopper 13 must be locked to each other regardless of the rotational position of the output shaft 11. It is turned. After the locking, the output shaft 11 is 5 °
A pulse signal is sent to the stepping motor 2 so that the output shaft 11 is returned, and the initial position of the output shaft 11 is accurately recognized.
By setting this initial position as the origin position for control and sending a signal corresponding to the amount of rotation from the origin to the position to be controlled to the stepping motor 2, the output shaft 11 can accurately reach the predetermined rotational position to be controlled. It is turned.

In the electric actuator 1 configured as described above, it is not necessary to provide a board, a brush, and the like unlike the conventional electric actuator, and the number of points can be reduced, and the product cost can be reduced. Also, since the number of parts can be reduced, in this embodiment, in particular, the first stopper 12 can be formed integrally with the gear 8 and the second stopper 13 can be formed integrally with the lower case 4b. It can be done easily.

Further, as described above, θ is set to the normal operation range of the output shaft 11 + 2α °, the first stopper 12 and the second stopper 13 are temporarily locked and then returned by α ° to recognize the initial position. Except when the stopper is locked in the initial position recognition operation, the lock torque by the stepping motor 2 is not applied to each part, so that the load on each part can be reduced and the life of each part can be extended.

When the electric actuator 1 is used in a vehicle air conditioner, the initial position recognition operation signal is generated by, for example, an engine-on signal. An operation can be performed, and subsequently, control to a desired air-conditioning state can be performed.

[0023]

As described above, according to the electric actuator and its control method of the present invention, it is possible to perform a predetermined output shaft initial position recognizing operation while reducing the number of parts. It is possible to provide an electric actuator having good attachment properties.

If the locking position of both stoppers is set to the position of the normal operation range of the output shaft + α °, and both stoppers are temporarily locked and then returned by α ° to recognize the initial position, Except during the position recognition operation, the lock torque of the motor can be prevented from being applied, which can contribute to prolonging the life of each part.

Furthermore, by using the electric actuator of the present invention for operating various dampers of a vehicle air conditioner, quick and accurate air conditioning control can be performed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an electric actuator according to one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view taken along line AA of FIG. 1 in a state where the electric actuator of FIG. 1 is assembled.

3 is a view of a fourth gear (final gear) of the electric actuator of FIG. 1 as viewed in the direction of arrow B in FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 electric actuator 2 stepping motor 3 stepping motor output shaft 4 case 4a upper case 4b lower case 5 first gear 6 second gear 7 third gear 8 fourth gear 9 as final gear 9, 10 support shaft 11 output of electric actuator Shaft 12 First stopper 13 Second stopper 20 Controller θ Movable angle α Angle returned for initial position recognition (margin angle) β Normal operating range

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02P 8/00 H02P 8/00 303B

Claims (5)

[Claims] 1. A stepping motor, a case to which the stepping motor is attached, an output shaft protruding from the case, and two or more gears provided between the stepping motor and the output shaft in the case. Consisting of
An electric actuator having a final gear and a gear group connected to the output shaft, wherein the final gear and the inside of the case can be locked to each other in a rotation direction of the output shaft, and An electric actuator provided with a stopper capable of recognizing an initial position of the output shaft via the control shaft. 2. The electric actuator according to claim 1, wherein a locking position of the two stoppers is set to a position within a normal operation range of the output shaft + α °. 3. The electric actuator according to claim 2, wherein said α ° is in a range of 1 to 20 °. 4. The electric actuator according to claim 1, wherein the output shaft is connected to a rotary damper of a vehicle air conditioner. 5. The electric actuator according to claim 2, wherein
After once rotating the output shaft to the locking position of both stoppers,
A method for controlling an electric actuator, characterized by controlling a stepping motor to return.