JP2004009881A - Electric actuator system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase output torque of an electric actuator without increasing vibration or noise. <P>SOLUTION: A direct current motor 110 is adopted, and a rotating position is detected by a two phases pulse output system. Thereby, the inexpensive electric actuator 100 can be achieved, and the output torque of the electric actuator 100 can be increased without increasing vibration and noise. Further, a position returned from a position on which a link lever abuts on a stopper for several pulses is made to be an operation reference. Thus, deterioration of durability caused by creep can be prevented. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric actuator system, and is effective when applied to an electric actuator system that drives a movable member such as an air mix door or a mode switching door of a vehicle air conditioner.
[0002]
Problems to be solved by the prior art and the invention
In the invention described in Japanese Patent Application Laid-Open No. 11-18403, a stopper is provided in the output gear and the casing, a position where both stoppers collide is stored as an origin position, and a position deviated from the origin position is set as an operation reference and a stepping motor is used. Is controlling.
[0003]
However, a stepping motor has a small output torque, and in order to increase the output torque, it is necessary to take measures such as increasing the drive current or increasing the rotor, and the current capacity of the electric actuator and the motor drive circuit is increased. Will be invited.
[0004]
In addition, if the reduction ratio of the reduction mechanism is increased, the output torque on the output shaft can be increased. However, since the rotation speed of the stepping motor increases, vibration and noise increase.
[0005]
In view of the above points, the present invention firstly provides a new electric actuator system different from the conventional one, and secondly, increases the output torque of the electric actuator without increasing vibration and noise. Aim.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, the output shaft (127) is based on a DC motor (110) and a pulse signal generated according to a rotation angle of the DC motor (110). ), And a motor control means (200) for controlling the operation of the DC motor (110). The motor control means (200) comprises a DC motor (110). The position where the rotation is mechanically stopped is stored as the origin position, and the DC motor (110) is controlled using the position deviated from the origin position as an operation reference.
[0007]
The DC motor (110) has a large output torque and a low cost as compared with a stepping motor, so that it is not necessary to take measures such as increasing the drive current or increasing the size of the rotor. There is no need to increase the current capacity of the power supply.
[0008]
Further, since the output torque of the output shaft (127) can be increased without increasing the reduction ratio of the reduction mechanism, the rotation speed of the DC motor (110) can be reduced, and vibration and noise can be reduced. be able to.
[0009]
Therefore, a new electric actuator system different from the conventional one can be obtained at low cost, and the output torque of the electric actuator can be increased without increasing vibration and noise.
[0010]
According to a second aspect of the present invention, the rotation angle detecting means (220) detects the rotation angle based on two or more types of pulse signals having different phases generated according to the rotation angle. .
[0011]
According to a third aspect of the present invention, when the change of the pulse signal stops, the motor control means stores the origin position on the assumption that the rotation of the DC motor (110) has stopped mechanically. It is.
[0012]
According to a fourth aspect of the present invention, the position deviated from the origin position is a position returned from the origin position by a predetermined rotation angle detected by the rotation angle detection means (220).
[0013]
According to the fifth aspect of the invention, the movable stopper (160), which rotates in conjunction with the rotation of the output shaft (127), collides with the fixed stopper (5a), thereby mechanically rotating the DC motor (110). When the DC motor (110) is stopped, the predetermined rotation angle is larger than the rotation angle at which the movable stopper (160) overruns due to inertia.
[0014]
This prevents the movable stopper (160) from colliding with the fixed stopper (5a) even if the movable stopper (160) is overrun due to inertia during the control of the DC motor (110). (160) and the mechanical strength of the fixed stopper (5a) can be prevented from lowering.
[0015]
Incidentally, the reference numerals in parentheses of the respective means are examples showing the correspondence with specific means described in the embodiments described later.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
In this embodiment, an electric actuator system (hereinafter, abbreviated as an actuator) 100 according to the present invention is applied to a driving device of an aerodynamic door 1 of a vehicle air conditioner, and FIG. 1 is a schematic diagram of a vehicle air conditioner. FIG. 2 is an external view of the actuator.
[0017]
Here, the air mix door 1 refers to the temperature of the air blown into the room by adjusting the amount of air flowing around the heater core 3 that heats the air blown into the room using the cooling water of the engine 2 as a heat source in the vehicle air conditioner. Is to adjust.
[0018]
The heat exchangers such as the heater core 3 and the evaporator 4 and the air mix door 1 are housed in an air-conditioning casing 5 made of resin, and the actuator 100 is fixed to the air-conditioning casing 5 by fastening means such as screws. I have.
[0019]
Next, the actuator 100 will be described.
[0020]
FIG. 2 is an external view of the actuator 100, and FIG. In FIG. 3, a DC motor 110 is directly connected to a battery mounted on a vehicle to rotate by obtaining electric power, and a speed reduction mechanism 120 reduces the rotational force input from the motor 110 to rotate the air mixing door 1. This is a speed change mechanism that outputs power toward. In addition, a mechanism unit that rotationally drives the DC motor 110 and the speed reduction mechanism 120 is referred to as a driving unit 130.
[0021]
Incidentally, the speed reduction mechanism 120 is a gear train including a worm 121 pressed into the output shaft 111 of the motor 110, a worm wheel 122 meshing with the worm 121, and a plurality of spur gears 123 and 124, and is located on the output side. An output shaft 127 is provided on the last stage gear (output side gear) 126.
[0022]
The casing 140 for the actuator is a casing that houses the drive unit 130 and to which brushes (electric contacts) 155 to 157 described later are fixed.
[0023]
By the way, as shown in FIGS. 3 to 6 (particularly, see FIG. 6), on the output side (output shaft 127) of the input gear (worm 121) directly driven by the DC motor 110 in the reduction mechanism 120, as shown in FIGS. A pattern plate (hereinafter, referred to as a pattern plate) 153 is provided. The pattern plate 153 includes first and second conductive portions 151a and 152a and non-conductive portions 151b and 152b alternately arranged in a circumferential direction. It is provided with pulse patterns 151 and 152 and rotates integrally with the output shaft 127.
[0024]
At this time, the circumferential angles α1, α2 of the conductive portions 151a, 152a and the circumferential angles β1, β2 of the non-conductive portions 151b, 152b are made equal to each other, and the phase of the first pulse pattern 151 is changed to the phase of the second pulse pattern 152. With respect to the circumferential angles α1, α2 (= circumferential angles β1, β2).
[0025]
The first and second pulse patterns 151 and 152 are electrically connected to each other, and the first and second pulse patterns 151 and 152 are common patterns (common conductive portions) provided on the inner peripheral side of the both pulse patterns 151 and 152. (Pattern) 154, and is electrically connected to the negative electrode side of the battery via a brush 157 described later.
[0026]
On the other hand, the first to third brushes (electric contacts) 155 to 157 made of a copper-based conductive material connected to the positive electrode side of the battery are fixed to the casing 140 in FIG. The second brush 156 is in contact with the pulse pattern 151, the second brush 156 is in contact with the second pulse pattern 152, and the third brush 157 is in contact with the common pattern 154.
[0027]
In this embodiment, the number of contacts between the first to third brushes 155 to 157 and the pattern plate 153 is two or more (four in this embodiment), so that the first to third brushes 155 to 157 are electrically conductive. The electrical connection with the parts 151a and 152a (including the common pattern 154) is ensured.
[0028]
As shown in FIG. 2, a link lever 160 for swinging the air mix door 1 is press-fitted and fixed to the output shaft 127, and a stopper 5a for causing the link lever 160 to collide with the air-conditioning casing 5. Is provided.
[0029]
Next, a schematic operation of the actuator 100 will be described.
[0030]
FIG. 7 is a schematic diagram showing an electric control circuit 200 of the actuator 100 serving as a motor control means. The electric control circuit 200 is based on a motor drive circuit 210 for driving the DC motor 110 and a pulse signal generated by the pattern plate 153. A rotation angle detector 220 for detecting a rotation angle and a rotation direction of the output shaft 127, and a storage circuit 230 such as an EEPROM for storing various control information.
[0031]
The electric control circuit 200 is supplied with a signal voltage indicating whether an ignition switch is on or off and power from a battery.
[0032]
When the DC motor 110 rotates and the output shaft 127, that is, the pattern plate 153 rotates, the first and second brushes 155 and 156 and the conductive portions 151a and 152a come into contact with each other, and the first and second brushes 155 and 156 contact each other. Non-energized (OFF) states in which the brushes 155 and 156 and the non-conductive portions 151b and 152b are in contact with each other periodically occur.
[0033]
Therefore, the first and second brushes 155 and 156 generate A-phase and B-phase pulse signals each time the DC motor 110 rotates a predetermined angle as shown in FIG. The rotation angle of the output shaft 127 can be detected by counting by the device 220.
[0034]
As is apparent from the above description, in the present embodiment, the pulse generator 158 (see FIG. 9) that generates a pulse signal every time the output shaft 127 rotates by a predetermined angle by the first and second brushes 155 and 156 and the pattern plate 153. 7).
[0035]
Further, since the phase of the first pulse pattern 151 and the phase of the second pulse pattern 152 are shifted, the pulse generator 158 generates a pulse signal generated by the first pulse pattern 151 and the first brush 155 (hereinafter referred to as a pulse signal). A pulse signal is referred to as an A-phase pulse, and a pulse signal having a phase shifted from the A-phase pulse generated by the second pulse pattern 152 and the second brush 156 (hereinafter, this pulse signal is referred to as a B-phase pulse). ) Occurs.
[0036]
For this reason, in the present embodiment, the rotation direction of the DC motor 110 (output shaft 127) is detected based on which signal of the A-phase pulse and the B-phase pulse is input to the rotation angle detector 220 first. I have.
[0037]
In controlling the amount of rotation of the DC motor 110, that is, the amount of rotation of the output shaft 127, the link lever 160 in FIG. 2 is caused to collide with a stopper 5a fixed to the air-conditioning casing 5 to control the rotation of the DC motor 110 mechanically. Is stored as the origin position, and thereafter, the position deviated from the origin position, that is, in the present embodiment, two pulses from the origin position except when the battery is disconnected and when an abnormality occurs in the pulse signal. The DC motor 110 is controlled using the returned position as an operation reference.
[0038]
Incidentally, the amount of return from the origin position is the number of pulses in consideration of the amount of overrun when the motor is stopped and the amount of bending of the link lever 160 and the stopper 5a when the link lever 160 collides with the stopper 5a.
[0039]
That is, when the link lever 160 is stopped at the stop position (operation reference), it is conceivable that the link lever 160 overruns beyond the stop position due to the inertia of operation. That is, the two pulses in the present embodiment are shift amounts that allow for the maximum value of the amount of overrun of the link lever 160 after the motor stop control.
[0040]
By setting the shift amount, it is possible to prevent the link lever 160 forming the movable stopper from overrunning during normal operation and colliding with the stopper 5a forming the fixed stopper to stop. A creep state can be avoided, and a decrease in the strength of the resin component can be prevented.
[0041]
It should be noted that it is difficult for a rotation angle detection device that detects a change in electric resistance (voltage change) to detect a rotation angle to control by returning such a small amount, but it is necessary to count the number of pulses. In the rotation angle detection device that detects the rotation angle, it is relatively easy to perform control by returning such a small amount. Can be realized.
[0042]
FIG. 9 is a subroutine flowchart showing the control of the actuator 100, that is, the DC motor 110. The main routine (not shown) monitors the on / off state of the ignition switch of the vehicle. When the ignition switch is turned on, After connecting the battery, the storage circuit 230 determines whether or not the ignition switch is turned on for the first time based on the flag (S110). When the ignition switch is turned on for the first time after connecting the battery, the link lever is turned on. The position at which the rotation of the DC motor 110 is stopped mechanically by causing the DC motor 110 to collide with the stopper 5a is stored as the origin position, and the position deviated from the origin position is set as an operation reference to reach the target position (target rotation angle). Control the motor 110 (S120 to S190)
[0043]
At this time, S150 may be omitted. That is, the link lever 160 does not stop at the operation reference in S150, and may stop at the operation reference only when the link lever 160 moves to and returns to the target position in S160 to S180.
[0044]
Incidentally, in the present embodiment, when the change of the pulse signal stops, it is determined that the link lever 160 has collided with the stopper 5a.
[0045]
On the other hand, when the ignition switch is not turned on for the first time after the battery is connected, the initial position setting step (S120 to S150) is not performed, and the direct current is shifted to the target position using the position deviated from the origin position as the operation reference. The motor 110 is controlled (S160 to S190).
[0046]
Even if the ignition switch is turned off, if the ignition switch is turned off for the first time after connecting the battery, the initial position setting step (S120 to S120) is performed to correct a malfunction at the time of battery power chattering. An initial position setting step (S200 to S230) is performed in the same manner as in S150).
[0047]
The malfunction during the battery power chattering means that when the battery is connected, such as when the battery is exchanged, the power supply is temporarily disconnected (chattering) and the operation of the electric control circuit 200 is unstable, and the home position is determined. And that the operation criteria are memorized.
[0048]
Also, if the link lever 160 is stopped at the origin position, the strength of the link lever 160 and the stopper 5a is reduced due to the creep phenomenon of the resin, so that S230 should not be omitted.
[0049]
Next, the operation and effect of the present embodiment will be described.
[0050]
As is well known, the DC motor 110 has a larger output torque than the stepping motor, so that it is not necessary to take measures such as increasing the drive current or increasing the rotor, and the current capacity of the actuator 100 and the motor drive circuit 210 is reduced. There is no need to make it large.
[0051]
Further, since the output torque of the output shaft 127 can be increased without increasing the reduction ratio of the reduction mechanism, the rotation speed of the DC motor 110 can be reduced, and vibration and noise can be reduced.
[0052]
In addition, since the number of pulses is returned after the origin position is stored, it is possible to prevent the link lever 160 and the stopper 5a from colliding with each other and maintaining the state while an excessive stress is applied to the both 160 and 5a.
[0053]
Accordingly, it is possible to prevent the resin parts such as the stopper 5a and the link lever 160 from creeping and reducing the strength, and thus it is possible to improve the durability of the actuator 100 and the air conditioner.
[0054]
Further, since the rotation position of the output shaft 127 is detected based on the pulse signal, the position detection accuracy can be improved as compared with the case where the rotation position of the output shaft 127 is detected by a potentiometer. As a result, the temperature of the air mix door 1 can be accurately controlled, so that the temperature control characteristics of the air conditioner can be improved.
[0055]
(2nd Embodiment)
In the first embodiment, when the pulse signal stops changing, it is determined that the link lever 160 has collided with the stopper 5a. However, in the present embodiment, as shown in FIG. 10, S130 and S210 in FIG. A signal (current) for rotating the link lever 160 toward the stopper 5a is supplied to the DC motor 110 for a predetermined time, and the position of the link lever 160 when the predetermined time has elapsed is stored as the origin position. .
[0056]
(Other embodiments)
In the above embodiment, two types of pulse signals having different phases are generated. However, the present invention is not limited to this, and one type or three or more types of pulse signals may be generated.
[0057]
Further, in the above embodiment, the electric actuator system according to the present invention is applied to the air mix door 1, but the present invention can be applied to other movable members such as a blow mode switching door.
[0058]
Further, in the above-described embodiment, the present invention has been described by taking the position detecting device of the sliding contact type as an example. However, the present invention is not limited to this, and may be applied to other position detecting devices such as an optical encoder. Can also be applied.
[0059]
In the above-described embodiment, as shown in FIG. 7, the pulse generator 158 is provided on the output shaft 127 to generate a pulse in association with the rotation of the output shaft 127, but the present invention is not limited to this. Instead, for example, in order to rotate the pattern plate 153 of the pulse generator, a rotating unit that is further decelerated than the output shaft 127 may be provided to generate a pulse signal.
[0060]
Further, in the above-described embodiment, the pattern plate 153 is configured by a printed circuit board, but the present invention is not limited to this. The pattern plate 153 may be formed by pressing a plate.
[0061]
Further, in the above-described embodiment, the common pattern (common conductive portion pattern) 154 provided on the inner peripheral side of both the pulse patterns 151 and 152 is provided. However, the present invention is not limited to this. The common pattern 154 may be provided on the outer peripheral side of the patterns 151 and 152, or the common pattern 154 may be provided between the pulse patterns 151 and 152.
[0062]
Further, in the above embodiment, the present invention is applied to the vehicle air conditioner, but the application of the present invention is not limited to this.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a vehicle air conditioner.
FIG. 2 is an external view of the electric actuator according to the first embodiment of the present invention.
FIG. 3 is a schematic view of the electric actuator according to the first embodiment of the present invention.
FIG. 4A is a front view of a pulse plate according to the first embodiment of the present invention, and FIG. 4B is a side view of FIG.
FIG. 5 is a sectional view taken along line AA of FIG. 3;
FIG. 6 is an enlarged view of a pulse plate according to the first embodiment of the present invention.
FIG. 7 is a schematic diagram showing a control circuit of the electric actuator according to the first embodiment of the present invention.
FIG. 8 is a pulse signal chart of the electric actuator according to the first embodiment of the present invention.
FIG. 9 is a control flowchart of the electric actuator according to the first embodiment of the present invention.
FIG. 10 is a control flowchart of an electric actuator according to a second embodiment of the present invention.
[Explanation of symbols]
100: electric actuator, 110: DC motor, 120: reducer,
127: output shaft, 151: first pulse pattern,
152: second pulse pattern, 153: pattern plate,
154: common pattern, 155: first brush, 156: second brush,
157: Third brush.

Claims (5)

A DC motor (110);
Rotation angle detection means (220) for detecting the rotation angle of the output shaft (127) based on a pulse signal generated according to the rotation angle of the DC motor (110);
Motor control means (200) for controlling the operation of the DC motor (110),
The motor control means (200) stores a position where the rotation of the DC motor (110) is mechanically stopped as an origin position, and uses the position deviated from the origin position as an operation reference for the DC motor (110). An electric actuator system characterized by controlling: The electric actuator system according to claim 1, wherein the rotation angle detection means (220) detects the rotation angle based on two or more types of pulse signals having different phases generated according to the rotation angle. 3. The motor control unit according to claim 1, wherein when the pulse signal stops changing, the rotation of the DC motor is mechanically stopped and the origin position is stored. 4. An electric actuator system as described. The position deviated from the origin position is a position returned from the origin position by a predetermined rotation angle detected by the rotation angle detection means (220). 3. The electric actuator system according to claim 1. By causing a movable stopper (160) that rotates in conjunction with the rotation of the output shaft (127) to collide with a fixed stopper (5a), the rotation of the DC motor (110) is mechanically stopped,
The electric motor according to claim 4, wherein the predetermined rotation angle is a rotation angle larger than a rotation angle at which the movable stopper (160) overruns due to inertia when the DC motor (110) is stopped. Actuator system.

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