JPS6248079B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a DC motor for driving a blower fan, and a control transistor connected in series with the DC motor to adjust the voltage applied to the DC motor. The present invention relates to a blower fan speed control device suitable for use in vehicle air conditioners and the like.

[Conventional technology]

Using a semiconductor element (transistor) to control the speed of the blower fan has the advantage of being able to control the amount of air flow in multiple or stepless steps, but on the other hand, there is a risk that the transistor may be damaged due to the blower fan locking up.

When we investigated the causes of motor lock, we found that there are two types: complete lock due to foreign matter contamination, and incomplete lock due to snow entering or oil hardening. It has been found that in the former case, continuing to supply power to the motor for a long time does not improve the situation, but in the latter case, it is possible to release the lock by continuing to supply power for a relatively short period of time.

When we conducted an experiment to unfreeze a DC motor that had been locked due to freezing by applying the maximum voltage (for example, 12V in a vehicle), we found that if a low voltage (for example, 4 to 6V) was applied immediately after the freeze was removed, Depending on the degree of freezing, the motor may stop or rotation may become unstable.

[Problem that the invention seeks to solve]

In view of the above-mentioned points, an object of the present invention is to provide a blower fan speed control device that has a lock release function for temporary locks and that suppresses the blower fan speed from becoming unstable when the lock is released. shall be.

[Means for solving problems]

Therefore, in order to achieve the above object, the present invention has the following features:
As shown in FIG. 4, it includes a DC motor 5 for moving the blower fan F, and a control transistor Tr ₂ connected in series with the DC motor 5 to adjust the voltage applied to the DC motor 5. In the blower fan speed control device, a detection means SSM detects the lock of the DC motor 5 according to the magnitude of the load current or terminal voltage of the DC motor 5 and outputs a detection signal; A voltage applying means VSM applies a voltage for releasing the lock to the DC motor 5 within a predetermined time in response to a signal, and a detection means SSM detects the voltage in response to the application of the voltage by the voltage applying means VSM. A technical means of providing an interrupting means STM for temporarily interrupting the action is adopted.

Here, for example, the main parts of the detection means SSM and the interruption means STM can be processed by a digital computer.

In the voltage applying means VSM, a relay contact connected in parallel with the control transistor Tr ₂ can be used.

[Effect]

In the present invention, by employing the above technical means, the following effects can be obtained.

First, when the DC motor 5 is not locked, the voltage applied to the DC motor 5 is controlled by the control transistor _Tr2 . Therefore, the DC motor 5 adjusts the speed of the blower fan F according to this applied voltage.

Here, when the DC motor 5 locks, the blower fan F stops, and the magnitude of the load current relative to the voltage applied to the motor 5 increases compared to normal. The detection means SSM detects this increase in load current and outputs a detection signal indicating that the motor 5 is in a locked state. The voltage applying means VSM receives this detection signal and applies a voltage to the motor 5 to release the lock within a predetermined time.

Therefore, if the motor 5 is completely locked due to foreign matter, etc., the voltage applying means
Since voltage application by the VSM is stopped after a predetermined period of time, the motor 5 will not be damaged.

In addition, if the lock of the motor 5 is not completely locked due to oil hardening, etc., the voltage applying means
By applying voltage from the VSM, the DC motor 5 receives energy capable of releasing the incomplete lock.
The lock state is released.

Here, due to the voltage application by the voltage application means VSM, the load current of the motor 5 is temporarily reduced during a transition period when the DC motor 5 shifts from the locked state to the completely released state. Therefore, if the load current state during this transition period is detected, even though the DC motor 5 is not completely released,
When the voltage application by the voltage application means VSM is stopped, the DC motor 5 becomes locked again.

However, according to the invention, the interrupting means STM
At the time of the above transient, the detection means SSM
Since the detection function of the motor 5 is interrupted and the detection means SSM outputs a detection signal indicating the detection result at the time of locking, the motor 5 has no power until it reaches a completely released state.
Voltage application is performed by voltage application means VSM.

〔Effect of the invention〕

Therefore, according to the present invention, there is an effect that a temporary incomplete lock can be restored to a completely released state.

Moreover, by interrupting the detection action of the detection means during the transition from the locked state to the completely released state, false detection during the transition can be prevented, and thereby the speed of the blower fan can be prevented from becoming unstable during the transition. The effect is that it can be prevented.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which a blower fan speed control device according to the present invention is applied to blower fan speed control of a car air conditioner will be described in detail.

FIG. 1 shows a circuit diagram of a blower fan speed control device according to the present invention. In FIG. 1, a microcomputer is used which performs arithmetic processing according to a predetermined air conditioner control program.

1 is an air conditioner operation panel, which includes an air volume setting device 1a for stopping the air conditioner and selecting blower mode OFF, AUTO, and Lo to Hi; a room temperature setting section 1b for setting the room temperature (°C); and a suction blowing mode (not shown) selected. It has a mode setting device, a blower motor lock indicator 1c, etc. 2 is a sensor that detects the outside temperature, 3 is a sensor that detects the inside temperature, 4
are other outlet temperature sensors, etc. 5 is a direct current motor for driving the ventilation fan, that is, a blower motor; 6 is a galvanic resistor having a minute resistance value for detecting the motor current; Tr ₁ and Tr ₂ are power transistors for controlling the speed of the ventilation fan; 8 is a fan speed control circuit; This is a resistor with a large resistance value equivalent to Lo, and it works to partially bypass the motor current rather than letting it flow entirely to the power transistors Tr ₁ and Tr ₂ , and to start the motor. 9 is a Hi relay corresponding to the voltage application means of the present invention, and has a function of causing the blower motor 5 to operate in Hi mode. 10 is an A/D converter that converts analog signals from the control panel 1, outside air sensor 2, inside air sensor 3, and other sensors 4 into digital signals and sends them to the microcomputer 11. Moreover, this A/D converter 10 includes:
A voltage V _M between the motor terminals for detecting the lock of the motor 5 and a voltage V _R across the galvanic resistor 6, which corresponds to a part of the detection means of the present invention, are input and converted into digital values. In addition, the above voltage V _R is the motor 5
is converted into a load current I _M (hereinafter referred to as motor current). The microcomputer 11 is a single-chip computer that performs arithmetic processing according to a predetermined air conditioner control program. 1
2 is a D/A converter which converts the digital air volume signal from the computer 11 into an analog signal and sends it to the power transistors Tr ₁ and Tr ₂ . Reference numeral 13 denotes an actuator for driving a suction/outlet switching damper, temperature control damper, other compressors, and water valves of the air conditioner (not shown), which are operated according to command signals from the microcomputer 11. 14 is a battery, and 15 is an ignition (IG) switch. 1
6 is a heater relay that turns on and off the blower power supply.

FIG. 2 is a flowchart showing the processing procedure of the blower fan speed control device according to the present invention.

In a vehicle equipped with the device of the present invention, when the IG switch 15 is turned on, the microcomputer 1
Power is supplied to the computer 1, and arithmetic processing starts from the initialization routine at step 100. step
100 sets the initial value necessary for arithmetic processing. Especially regarding blower control, the blower lock flag F _R =
0, air conditioner start flag F _S = 0, air conditioner running flag F _D = 0, low temperature blower lock flag F _H = 0, timer T ₃ = 5 seconds. In the next step 101, a data reading routine is performed to set the blower mode. (OFF, AUTO, Lo to Hi), outside temperature (Tam), inside temperature, other sensor blower motor terminal voltage V _M Value converted from voltage across galvanic resistor V _R to motor current (I _M ), other settings Processing is performed to store the data of the device, etc. in a predetermined memory. However, in step 1010, when timer T ₂ is 0 < T ₂ < 0.3 seconds, _{VM and IM} are considered to be in a transient state and the data are not updated. Update by transferring to another memory location.

Step 102 is a step to determine whether the air volume setting device is in the off mode, that is, the air conditioner is not operating.If the air volume setting device is in the off mode, the process goes to step 103, where the heater relay is turned off, the actuator is stopped, and the start flag F _S =0, the air conditioner is running. Flag F _D =
0, go to step 101, and continue at step 101 until the off mode is released.
102 and 103 will be repeated. Next, if the motor is not in the off mode, the process goes to step 104, and it is determined from the lock flag F _R whether the motor is locked or not. If F _R = 1 (locked), the motor lock indicator 1c is activated in step 105, as will be described later. , the process moves to step 125, which is A/O control program processing other than blower control. On the other hand, when F _R =0, the step
106, determines whether it is time to start the A/C from the start flag F _S , and at the time of start (F _S = 0), controls the blower motor start, that is, opens the power transistors Tr ₁ and Tr ₂ for a certain period of time when the motor starts. , Lo resistor 8 to apply current to the motor 5 to perform control to protect the power transistors Tr ₁ and Tr ₂ from destruction due to excessive starting current.

Specifically, when F _S =0 (at the start) in step 106, the process goes to step ₁₀₇ , starts the timer T1 to 0, sets F _S =1, and turns on the heater relay 16 in step 108, at the same time turning on the blower Lo. (power transistors Tr ₁ and Tr ₂ are opened), and the process moves to step 125. If it is not the start time in step 106 (F _S = 1), go to step 109 and judge whether 2 seconds have elapsed on timer _T1 . If it is within 2 seconds, nothing is done, that is, blower Lo is turned off. Exit to step 125. After 2 seconds have elapsed, the timer _T1 is stopped in step 110, and the process moves on to a process of determining whether or not the motor 5 is locked.

FIG. 3 shows a voltage/current characteristic diagram of the blower motor used in the present invention during normal operation and when the blower motor is locked.
That is, it shows the applied voltage V _M and current I _M of the blower motor, where characteristic a is the measurement result when the blower motor is normal, and characteristic b is the measurement result when the blower motor is locked.

As can be seen from FIG. 3, when the motor 5 is locked, the current increases abnormally. Therefore, a lock judgment criterion is set as shown by the broken line C, and the motor current I _M with respect to the voltage V _M at that time is lower than the broken line C. If it is large, it can be determined that the lock is in place. Therefore, according to the present invention, in step 111, a reference current I, which is a lock judgment criterion, is determined from the motor applied voltage V _M , and in the next step 112, a comparison is made with the motor current I _M determined from the galvanic resistor 6. , the result is IM＞
If it is I, it is determined that the lock is locked, and the process goes to step 126. If not, the process goes to step 114, where timer _T2 is stopped and FD=1 is set. However, according to the present invention, in step 1100, timer _T2 does not newly calculate I before 0.3 seconds have elapsed, that is, when motor applied voltage V _M and motor current I _M are in a transient state. Next, go to step 1140 and determine whether the low temperature flag F _H is 1. If it is 1, it means that the motor 5 has been unfrozen and the motor has just started rotating, so go to the next step 1141. Start the forward timer T ₃ from 0 seconds and at the same time set F _H to F _H = 0.
Set it again and move on to step 125. step
If F _H =0 at 1140, the process goes to step 1142, where it is determined whether timer _T3 has elapsed for 2 seconds. If timer _T3 is within 2 seconds, step 125
go to In other words, once the freeze motor lock is released, a process is performed to fix it at Hi for 2 seconds. If T ₃ >2 seconds in step 1142, the process goes to step 1143, stops timer _T3 , and goes to step 115.

Also, in step 115, it is determined whether the air volume setting device 1a is automatic (AUTO) or manual (Lo to Hi), and if it is manual, the D/A converter is set to the air volume set by the air volume setting device 1a. At step 116, processing for sending a signal to 12 is performed, and the process proceeds to step 125.

On the other hand, in the case of automatic (AUTO), the step
117, and perform conventional blower automatic (AUTO) control, such as automatically increasing the air volume as the difference between the room temperature and the set room temperature increases, or increasing the air volume when the blowing air temperature is high or low. , when the temperature is intermediate, control is performed to reduce the air volume, and the process moves to step 125. When it is determined in step 112 that the blower motor is locked, the process proceeds to step 126, where a process is performed to determine whether or not the blower motor is locked while it is rotating. If the motor locks while it is rotating (F _D = 1), it is not a lock that can be released due to freezing, but a lock due to foreign matter, etc., so go to step 119 and turn off the blower (heater relay off). In the next step 120, the blower lock flag F _R is set to F _R =1, and the process goes to step 125.
If F _D ≠ 1 in step 126, the motor is locked at startup, so depending on the outside temperature, it is necessary to decide whether to cut off the motor current immediately after detecting the lock, or to let current flow through the motor for a certain period of time to release the freeze. The program moves on to the step 113 where judgment processing is performed.

Step 113 is where the low-speed blower lock flag F _H is monitored. When F _H = 1, a lock is detected at startup, the 2-second timer T ₂ is activated, and the blower is set to Hi.
Since the motor 5 is under control (actually, the motor 5 is locked, but a high voltage is applied to the motor 5), the process goes to step 123 in which it is determined whether or not the timer _T2 has elapsed for 2 seconds. At step 113, F _H =
If it is 0, this is the first time that the startup lock has been detected, so the process moves to step 118 to determine the outside temperature. If the outside temperature is 0°C or higher in step 118, the lock is not due to freezing, so go to step 119 and turn off the blower (heater relay off).In the next step 120, set the blower lock flag F _R to 1, and then proceed to step 119. Move to 125. Outside air is 0℃ in step 118
In the following, if it is determined that there is a possibility of the motor lock being released, timer _T2 is started in step 121, the low temperature lock flag F _H is set to 1, and blower Hi relay 9 is turned on in the next step 122 to turn on the blower. It performs processing to operate at Hi, and proceeds to step 123 where it is determined whether timer T ₂ seconds has elapsed. When _T2 has elapsed for 2 seconds, the motor 5 is energized for 2 seconds and the motor 5 is locked due to freezing due to heat generation and rotational torque during that time. Since this is not the case, timer _T2 is stopped in step 124, and the process proceeds to step 119, where the motor current is cut off. If T ₂ <2 seconds in step 123, nothing is done, that is, the process goes to step 125 with the blower motor Hi.

In step 125, air conditioner control other than air volume control is performed, for example, calculating the required air outlet temperature from the data of each sensor and setting device, operating the actuator 13 to achieve the set room temperature, and controlling the compressor and water valve. After processing, which is a known air conditioner control processing routine, the process goes to step 101.

Thus, according to the above embodiment, step 112
If it is determined in step 126 that the motor is in a locked state and that the motor is not rotating, then step 126 determines that the motor is not rotating.
At 122, the blower Hi relay 9 is actuated to apply voltage to the motor 5 to rotate it Hi, thereby releasing the lock. However, if this state continues for more than 2 minutes, it is determined that the lock is not temporary, and in step 119 the heater relay 16 is turned off to stop the power supply to the motor 5, and in step 105 it is determined that the motor is locked. Display.

Also, at this time, within at least 0.3 seconds from the activation of the blower Hi relay 9, step 1010,
As shown at 1011 and 1100, the values of the motor terminal voltage V _M and the voltage V _R across the galvanic resistor 6 input in step 101 are not transferred, and the lock detection current I is
It also does not calculate. Therefore, for 0.3 seconds after the timer T ₂ starts operating, the values of I and I _M at the time of the timer action are held, so the load current I actually changes during this time.
Even if _M has decreased, it is not detected and the blower Hi relay 9 continues to operate.

Further, according to the above embodiment, when it is determined in step 112 that the motor lock is released, the timer _T3 is activated in step 1141, and the motor 5 is activated for an additional 2 seconds.
Since Hi rotation is maintained, the warm-up effect of the motor is enhanced, allowing a smooth transition to normal blower motor control.

In the above embodiment, the startup timer _T1 is set to 2 seconds,
The low temperature lock timer _T2 is set to 2 seconds, and the lock detection stop timer is set to 0.3 seconds, and the timer _T3 is set to 2 seconds, but this is not a limitation.

In addition, the low temperature lock timer _T2 changes depending on the outside temperature.
For example, the lower the temperature, the longer the motor will not be destroyed, and the higher the temperature, the shorter the length.

Further, in the above embodiment, the motor lock is stored until the IG is turned off, but it may be refreshed in the off mode.

Further, although the lock detection is processed by a computer program, it may be configured by a hard logic circuit.

Furthermore, in the embodiment, the determination of whether the motor is frozen or locked is made based on whether the motor is locked at startup or when the outside temperature is low, but this is not intended to be limiting, and freezing can be determined from either one. Alternatively, the freeze determination may not be performed.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of a blower fan speed control device according to the present invention, Fig. 2 is a flowchart showing the processing procedure of the device shown in Fig. 1, and Fig. 3 is a diagram showing normal operation of the blower motor used in the present invention. FIG. 4 is an explanatory diagram showing an outline of the configuration of the present invention. 1... Air conditioner operation panel, 1a... Air volume setting device, 1c... Motor lock indicator, 2... Outside temperature sensor, 5... Blower motor, 6... Galvanic resistor, 8... Lo resistor, 9... …Blower Hi relay,
11...Microcomputer, 16...Heater relay.

Claims (1)

[Claims] 1. A DC motor for driving a blower fan;
A blower fan speed control device including a control transistor that is connected in series with the DC motor and adjusts the voltage applied to the DC motor, wherein the DC motor detects the lock of
a detection means for outputting a detection signal; a voltage application means for applying a voltage for releasing the lock to the DC motor within a predetermined time according to the detection signal of the detection means; A blower fan speed control device comprising: means for temporarily interrupting the detection action of the detection means in response to application.