JP2696990B2 - Liquid cooling device temperature controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a temperature control device of a liquid cooling device for maintaining a constant temperature of a cooling liquid for a machine tool or the like using a refrigeration circuit, and in particular, to a temperature control device for the liquid cooling device. The present invention relates to measures for improving the control accuracy of the coolant temperature.

(Prior art) Conventionally, in a liquid cooling device for circulating and cooling a cooling liquid of equipment such as a machine tool, a refrigeration circuit in which a compressor, a condenser, a decompression mechanism, and an evaporator are sequentially connected is arranged.
A common technique is to cool the liquid using the evaporating action of the refrigerant in the evaporator, and to perform feedback control by turning the compressor ON / OFF so that the liquid temperature converges to the set value. Have been.

(Problems to be Solved by the Invention) Incidentally, when the compressor is turned on and off as described above to control the liquid temperature of the liquid cooling device to converge to a predetermined set value, the liquid temperature change and the compressor As shown in FIG. 9, the relationship between the ON / OFF timing and the ON / OFF timing is as follows. When the liquid temperature (the inlet side temperature indicated by the broken line in the figure) drops from the high temperature side and reaches the set value, the compressor is turned OFF (FIG. 9). a ₁ , a ₂ , ...) On the other hand, when the liquid temperature rises from the set value and reaches a temperature with a certain differential with respect to the set value, the compressor is turned off.
To ON (figure b _1, b _2, ... time points) will be controlled to. Therefore, as shown by the solid line in the figure, the coolant temperature greatly changes in accordance with ON / OFF of the compressor, and there is a possibility that hunting may occur due to a response delay of a change in the device temperature based on the change.

Therefore, it is conceivable to adjust the operating capacity of the compressor so as to make the frequency variable by the inverter, thereby smoothing the change in the coolant temperature and improving the temperature control accuracy of the equipment.

However, even in such a case, when a disturbance acts on the control system, for example, when the thermal load state of the device is changed during the feedback control as described above, for example, when the rotation speed of the main shaft portion of the machine tool changes, the unstable element is generated. Is added, and there is a possibility that a sufficiently stable control function cannot be exhibited.

The present invention has been made in view of such a point, its purpose is to respond to disturbance quickly by taking a means to control the operation state of the cooling device according to the heat load state of the equipment,
An object of the present invention is to improve the temperature control accuracy by eliminating the control delay.

(Means for Solving the Problems) In order to achieve the above object, a solution of the present invention is to detect a thermal load state of a device and to control a capacity of a compressor corresponding to the state.

Specifically, as shown in FIG. 1 (including a dashed line portion not including a dashed line portion and a two-dot chain line portion), the first solving means includes the compressor (8) as a control means of the liquid cooling device. Inverter that variably adjusts the operating frequency of (15)
A liquid temperature detecting means (Th1) for detecting the temperature of the coolant in the liquid circulation circuit (3); and a liquid temperature detecting means (Th
Feedback control means (30) for receiving the output of (1) and controlling the output frequency of the inverter (15) so that the coolant temperature converges to a set value, and a thermal load for detecting a thermal load state of the device (1). Receiving outputs from the state detecting means and the heat load state detecting means, when the change in the heat load state of the device (1) becomes equal to or greater than a predetermined value, the frequency of the inverter (15) is adjusted by the feedback control means (30). Frequency changing means (31) for changing a frequency value to be controlled to a frequency value corresponding to a heat load when the device (1) changes is provided.

As shown in FIG. 1 (including a dashed-dotted line portion and a dashed-line portion without including a two-dot chain line portion), the second solving means presupposes the liquid cooling device in the first solving means, and as a control device thereof, An inverter (15) for variably adjusting the operating frequency of the compressor (8); and the liquid circulation circuit (3).
Temperature detection means (Th1) for detecting the temperature of the cooling liquid
A reference temperature detecting means (Th2) for detecting a temperature of a tuning reference object which is a reference for tuning the temperature of the coolant; a liquid temperature detecting means (Th1) and a reference temperature detecting means (Th
Feedback control means (30) for receiving the output of (2) and controlling the output frequency of the inverter (15) so that the temperature difference between the coolant temperature and the tuning reference temperature converges to the set value; A heat load state detecting means for detecting a heat load state; and receiving an output from the heat load state detecting means, and when the change in the heat load state of the device (1) exceeds a predetermined value, the frequency of the inverter (15) is changed. Frequency changing means (31) for changing a frequency value controlled by the feedback control means (30) to a frequency value corresponding to a heat load when the equipment (1) changes is provided.

As shown in FIG. 1 (including a dashed-dotted line portion and a dashed-dotted line portion without a broken line portion), the third solution means is based on the liquid cooling device in the first solution means, and its control device is An inverter (15) for variably adjusting the operating frequency of the compressor (8); and the liquid circulation circuit (3).
Temperature detection means (Th1) for detecting the temperature of the cooling liquid
Feedback control means (30) for receiving the output of the liquid temperature detection means (Th1) and controlling the output frequency of the inverter (15) so that the coolant temperature converges to a set value; A heat load state detecting means for detecting a heat load state; and an apparatus (1) receiving an output of the heat load state detecting means.
Frequency changing means (31) for changing the frequency of the inverter (15) based on the heat load state of the inverter (15), and controlling the frequency of the inverter (15) in response to a command signal from the outside by the feedback control means (30 If the change in the thermal load state of the device (1) detected by the thermal load state detecting means becomes a predetermined value or more while performing the control mode only by the feedback control means (30), the frequency changing means (31) ) To switch between a control mode in which the control for changing the frequency of the inverter (15) from the frequency value by the feedback control means (30) to a frequency value corresponding to the heat load at the time of change and a control mode using only the frequency changing means (31). And a control mode selecting means (17) for alternately selecting.

As shown in FIG. 1 (including a dashed-dotted line portion, a dashed-dotted line portion, and a dashed line portion), a fourth solution means is based on the same liquid cooling device as the first solution means, An inverter (15) for variably adjusting the operating frequency of the compressor (8); a liquid temperature detecting means (Th1) for detecting the temperature of the coolant in the liquid circulation circuit (3); A reference temperature detecting means (Th2) for detecting a temperature of a tuning reference object as a reference for tuning, a liquid temperature detecting means (Th1) and a reference temperature detecting means (T
h2), the feedback control means (30) for controlling the frequency of the inverter (15) so that the difference between the coolant temperature and the tuning reference temperature converges to a set value; A heat load state detecting means for detecting a heat load state; and a frequency changing means (31) for receiving an output of the heat load state detecting means and changing a frequency of the inverter (15) based on a heat load state of the device (1). And a control mode of the frequency of the inverter (15) according to a command signal from the outside, a control mode using only the feedback control means (30),
While the control by the feedback control means (30) is performed, when the change in the heat load of the device (1) detected by the heat load state detection means becomes a predetermined value or more, the frequency change means (31) controls the inverter (15). A control mode in which the frequency is changed from a frequency value by the feedback control means (30) to a frequency value corresponding to the heat load at the time of the change, and a control mode in which the control mode is selected only by the frequency change means (31). A mode selecting means (17) is provided.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the thermal load state detecting means is constituted by a temperature sensor.

A sixth aspect of the present invention is the device according to any one of the first to fourth aspects, wherein the heat load state detecting means is:
It is constituted by a sensor for detecting a mechanical distortion of an operating portion of the device (1).

According to a seventh aspect of the present invention, in any one of the first to the fourth aspects, the heat load state detecting means may include:
It is configured by a sensor that detects the load of the actuator of the device (1).

An eighth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, wherein the heat load state detecting means is:
When the device (1) is a machine tool, it is constituted by a sensor for detecting the rotation speed of the main shaft.

(Operation) According to the above configuration, in the invention of claim (1), in the liquid circulation circuit (3), the return liquid of the cooling liquid whose temperature has increased by absorbing the heat load of the device (1) is supplied to the refrigeration circuit (14). Is cooled by heat exchange with the refrigerant in the evaporator (11), and is again supplied to the device (1). On the other hand, in the refrigeration circuit (14), the refrigerant circulates so as to perform a heat pump function of applying the cold heat imparted to the refrigerant by heat exchange with air in the condenser (9) to the coolant in the evaporator (11).

Then, the feedback control means (30) controls the inverter (1) so that the temperature of the coolant of the device (1) detected by the liquid temperature detection means (Th1) converges to a predetermined set value.
The frequency of 5) is controlled, and the compressor (8)
Operating frequency is adjusted. As a result, the amount of heat exchange between the refrigerant and the liquid in the evaporator (11) is adjusted so as to keep the liquid temperature constant.

At this time, during the constant control of the coolant temperature by the feedback control, if the heat load state of the device (1) changes and the change exceeds a predetermined value, the frequency changing means (3
According to 1), the frequency value of the inverter (15) controlled by the feedback control means (30) is changed to a frequency value corresponding to the heat load at the time of change, according to the heat load state detected by the heat load state detection means. Therefore, the change in the thermal load state is quickly followed without causing a control delay due to the feedback control, so that hunting is effectively prevented and the control accuracy is improved.

In the invention of claim (2), the reference temperature detecting means (Th2)
The temperature of the tuning reference object, which is the reference for tuning the coolant temperature, is detected, and the difference between the coolant temperature and the tuning reference temperature is set to the set value by the feedback control means (30) and the frequency control means (31). Claim (1) to converge.
The same control as that of the invention is performed. Therefore, the same effects as those of the above-described claim (1) can be obtained while following changes in the environment.

In the invention of claim (3), the control mode selection means (SW
1) through (SW3), feedback control according to the coolant temperature of the device (1), control for switching from the feedback control to the frequency change control in the invention of claim (1), and the device (1). The frequency change control according to the heat load state is selectively selected, so that the operation of the cooling device is controlled in a preferable control mode according to the type of the device (1), the type of the work, and the like. The effect of the invention (1) is remarkably obtained.

According to the invention of claim (4), the control mode selecting means (SW
(1) The feedback control according to (SW3) according to the temperature difference between the tuning reference temperature detected by the reference temperature detecting means (Th2) and the coolant temperature of the device (1), and the invention according to claim (1). In the above, the control for switching from the feedback control to the frequency change control and the frequency change control according to the heat load state of the device (1) are selectively selected, so that the effect of the invention of claim (2) is remarkable. can get.

In the invention of claim (5), claims (1), (2),
In (3) or (4), when the temperature of the device (1) rises due to a change in the thermal load state, there is a predetermined time delay before the rise in temperature causes a change in the temperature of the coolant. At this time, since the temperature sensor is used as the heat load state detecting means, the temperature change of the device (1) is detected by the temperature sensor (Th3) as soon as possible, and the refrigeration capacity of the refrigeration circuit (14) is changed in advance. The control corresponding to the change in the thermal load state of the device (1) is quickly performed.

In the invention of claim (6), claims (1), (2),
In the invention of (3) or (4), since a sensor for detecting mechanical distortion of the operating section of the device (1) is used as the thermal load state detecting means, a change in the thermal load state such as a load applied to the operating section. Therefore, before the temperature of the coolant changes, the strain generated by the force applied to the operating portion of the device (1) and the change in temperature is detected as soon as possible. Is played.

In the invention of claim (7), claims (1), (2),
In the invention of (3) or (4), since a sensor for detecting a load applied to the actuator of the device (1) is used as the thermal load state detecting means, an increase in the load causes a temperature change, distortion, or the like of the operating portion. Is foreseen, and the effects of the inventions of claims (5) and (6) are remarkably exhibited.

In the invention of claim (8), claims (1), (2),
In the invention of (3) or (4), when the device (1) is a machine tool, a sensor for detecting the number of revolutions of the main spindle is used as the thermal load state detecting means. The change in temperature and strain is predicted, and the same operation as the invention of the above-mentioned claim (7) is achieved.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 shows a first embodiment, in which (1) is a machine tool as a device for performing predetermined machining, and (2) is an oil controller as a liquid cooling device for cooling a cooling oil of the machine tool (1). It is. The machine tool (1) includes a main shaft portion (1a) for attaching a cutting tool such as a milling blade or a drill blade to a tip,
An oil pipe (1b) for circulating cooling oil for absorbing a thermal load Q generated by machining or the like to the main shaft portion (1a) and maintaining the temperature constant, and a reservoir for receiving the cooling oil. (1c). In addition, the oil condenser (2) has a built-in oil circulation circuit (3) as a liquid circulation circuit that is connected to an oil pipe (1b) of the machine tool (1) so that oil can flow and circulates cooling oil. Have been. The oil circulation circuit (3) is provided with a constant displacement pump (4), which is rotationally driven by a motor (M) and forcibly circulates cooling oil, and is provided from a reservoir (1c) of the machine tool (1). Return oil flows in from the inlet port (5) of the oil con (2),
The oil is supplied again from the outlet port (6) to the oil pipe (1b) of the machine tool (1).

On the other hand, a refrigerating device (7) is built in the oil con (2), and the refrigerating device (7) includes a compressor (8),
A condenser (9) provided with a fan (9a) for condensing the refrigerant, a capillary (10) as a decompression mechanism for decompressing the refrigerant, and an oil circulation circuit for evaporating the refrigerant and exchanging heat with the refrigerant. (3) Evaporator (11) for cooling the cooling oil inside
And an accumulator (12) for separating gas-liquid in the refrigerant returning to the compressor (8). Each of the devices (8) to (12) is connected so that a refrigerant can flow through a refrigerant pipe (13), and cool heat obtained by heat exchange with air in a condenser (9) is converted into oil in an evaporator (11). A refrigeration circuit (14) that performs a so-called heat pump function and is provided to the cooling oil of the circulation circuit (3). That is, in the oil circulation circuit (3), the main spindle (1) of the machine tool (1) is used.
The cooling oil whose temperature has risen by absorbing the heat load Q in a) is cooled by the evaporator (11) and supplied to the machine tool (1) again, whereby the main shaft portion (1a) of the machine tool (1) is formed. ) Is kept constant, and a dimensional change due to the temperature change is suppressed to obtain a predetermined machining accuracy.

Then, (15) sets the operating frequency fn of the compressor (8) to n = 0 (stop) and n = 1 (30) as shown in Table 1 below.
Hz), n = 2 (40 Hz), n = 3 (50 Hz), n = 4 (60 Hz),
.., N = 10 (120 Hz).

Further, (16) is a controller for controlling the operation of the entire apparatus. The controller (16) includes a main circuit (16a) for controlling the apparatus and a thermal load state of the equipment (1). And an interface circuit (16b) for inputting a predetermined external signal based on the input signal and outputting the input signal to the main circuit (16a). The two circuits (16a) and (16b) are connected by signal lines so that signals can be exchanged. It is connected. further,
(Th1) is the temperature of the coolant which is attached to the inlet side of the oil circulation circuit (3), that is, the oil inlet joint of the pump (4) in the oil condenser (2) and returns from the machine tool (1) to the oil condenser (2). Oil temperature thermistor as liquid temperature detecting means for detecting oil temperature, (Th2) is the controller (16) of oil controller (2)
Mounted on the panel of the cooling oil The air temperature thermistor as a reference temperature detecting means for detecting the temperature of the indoor air (tuning reference temperature) T _A as a reference for tuning the temperature of the machine, (Th3) is a machine tool (1)
And a main shaft part thermistor as a heat load state detecting means for detecting a main shaft part temperature H corresponding to a heat load state of a machine tool (equipment).

The inlet oil temperature thermistor (Th1), the air temperature thermistor (Th2), and the inverter (15) are directly connected to the main shaft thermistor (Th3) via a control device (1d) on the machine tool (1) described later. Each controller (16)
The controller (16) controls the operation of the apparatus.

On the other hand, the control device (1d) for controlling the operation of the machine tool (1) includes a controller (1d) of the oil controller (2).
6) and signal transmission and reception, machine tool (1)
External signals such as ON / OFF of the main spindle (1a) can be input to the controller (16). Here, a spindle thermistor (Th3) arranged on the spindle (1a) of the machine tool (1) is connected to the control circuit (1d) so that signals can be input.

Further, as a feature of the present invention, the controller (16)
As shown in FIG. 3, the switch panel (17)
Mode switch (SW
1) to (SW3) are attached, and the mode switch (SW
When 1) is ON, two thermistors (Th1) and (Th
When the mode switch (SW2) is ON, the two thermistors (Th1) and (2) are in the thermo mode in which only the feedback control of the frequency of the inverter (15) is performed according to the signal of (2).
While performing the frequency feedback control in accordance with the signal of (Th2), the change of the spindle temperature H indicating the thermal load state of the machine tool (device) (1) detected by the spindle thermistor (Th3) is equal to or more than a predetermined value. When the mode switch (SW3) is ON in the forward control mode (hereinafter abbreviated as F / F mode) that switches to the control that changes the frequency value of the inverter to the frequency value corresponding to the spindle temperature H at the time of change , Signal from spindle thermistor (Th3) (external signal)
Control mode that changes the frequency only according to the
Mode). As will be described in detail later, in the F / F mode, when there is almost no change in the spindle temperature H, the current frequency of the inverter (15) controlled by feedback control is maintained as it is, that is, only feedback control is performed. If the change in the spindle temperature H is larger than a predetermined value, the inverter frequency controlled by the feedback control is increased or decreased by a predetermined step (or the compressor is stopped). It has been done. In the I / F mode, the inverter frequency value is changed according to the relationship between the spindle temperature and the set range. When the external command signal indicates, for example, that the spindle temperature H is lower than a predetermined value, the inverter frequency value is decreased. When the external command signal indicates that there is almost no change in the spindle temperature H, the current frequency value is maintained as it is. When the main shaft portion temperature H is lower than a predetermined value, control is performed to increase the frequency value.

That is, the mode switches (SW1) to (SW3)
The control mode of the frequency of the inverter (15) is a control mode using only feedback control, and a spindle thermistor (thermal load state detection means) while performing feedback control.
When the change in the thermal load state of the device (1) detected in (Th3) exceeds a predetermined value, the output frequency of the inverter (15) is changed from the frequency value by feedback control to the frequency value corresponding to the thermal load at the time of the change. And a control mode selecting means for selecting a control mode for switching to the control to be performed and a control mode only for changing the frequency.

As shown in FIG. 4, a storage device (not shown) built in the controller (16) has an inlet detected by the inlet oil temperature sensor (Th1) and an inlet temperature detected by the air temperature sensor (Th2). Temperature deviation ΔT between oil temperature T _O and air temperature T _A (= T _O −
Regarding T _A ), multiple temperature zones are set at 0.5 ° C. intervals with respect to a predetermined set value T _S that is a control target value. ΔT> T _S +
A temperature zones (3-U) in the range of 1.5 ℃, T _S + 1.5 ℃
≧ ΔT> T _S + 1.0 ° C. temperature zone (2-U)
And a temperature zone (1-U) in the range of T _S + 1.0 ° C. ≧ ΔT> T _S + 0.5 ° C., and a temperature zone (0−0) in the range of T _S + 0.5 ° C. ≧ ΔT> T _S U), a temperature zone (0-L) in the range of 0 ° C. ≧ ΔT> T _S −0.5 ° C., and T _S −0.5 ° C. ≧ ΔT> T _S
A temperature zone (1-L) in the range of −1.0 ° C .;
It is divided into a total of 10 multi-steps up to a temperature zone (5-L) in the range of T ≦ T _S −2.0 ° C. That is, the frequency of the inverter (15) based on whether the differential temperature ΔT inlet oil temperature T _O and air temperature T _A detected by the inlet oil temperature thermistor (Th1) and air temperature thermistor (Th2) are in which the temperature zone The value f is feedback-controlled.

In the interface circuit (16b), as shown in the following Table 2, addresses [2] to [7] are assigned to individual input connectors (not shown) having a function of allocating input / output signals of a total of 8 bits. Placed on 6
Bit signals are used for control. Here, the two-bit signals allocated to the first addresses [2] and [3] correspond to the switching signals of the mode switches (SW1) to (SW3). ) Selects the F / F mode, and (10) selects the I / F mode. Also,
The 4-bit signals located at addresses [4] to [7] are set for each type of control mode selected above, and the change dH / in the spindle temperature H detected by the spindle thermistor (Th3). This is an external command signal corresponding to the value of dt.

In Table 2, "-" in the external command signal means that the function is performed irrespective of whether the value is "0" or "1".

That is, in the thermo mode, the control command signals are all (----), and the interface circuit (16b)
Irrespective of the signal from the spindle, that is, the spindle thermistor (Th
Regardless of the signal of 3), feedback control is performed according to the signals of the inlet oil temperature thermistor (Th1) and the air temperature thermistor (Th2).

In the F / F mode, when the external command signal value corresponding to the case where the spindle temperature change dH / dt has almost no value is (0000) (no external signal) (neutral signal), the feedback control is performed. It is controlled so that the current frequency fn of the controlled inverter (15) is maintained as it is, that is, only feedback control is performed. Further, when the external command signal value corresponding to the case where the spindle temperature change -dH / dt is larger than a predetermined value (at the time of supercooling) is (-1-1), the compressor (1) is controlled to stop. You. On the other hand, when the external command signal value is (0001) to (1100), the inverter frequency fn controlled by the feedback control is increased or decreased by a predetermined step. That is, dH
In the case of (0001), which corresponds to the case of / dt = −ΔHo (for example, ΔHo = a value of about 0.2 ° C./sec), the amount decreases by two steps, and in the case of (0010), which corresponds to the case of dH / dt = −2ΔHo Decreases by 3 steps, decreases by 4 steps when dH / dt = -3ΔHo (0011), and increases by 2 steps when dH / dt = ΔHo (0100). , DH / dt = 2ΔHo (1000), which is increased by 3 steps, and dH / dt = 2ΔHo
In the case of (1100) corresponding to the case of 3ΔHo, the distance is increased by four steps.

On the other hand, in the I / F mode, when the external command signal value corresponding to the case where the spindle temperature H is lower than the predetermined value is (1111), the compressor (1) is stopped and the change dH / dt
In the case of (0000), which corresponds to the case where there is almost no case, the current frequency value fn is maintained as it is, and the main shaft portion temperature H is in each temperature zone divided into 10 zones at 0.5 ° C intervals above and below a predetermined standard temperature. (0001) to (1010) corresponding to
In this case, the inverter frequency fn is controlled to a value corresponding to each step of n = 1 to 11 shown in Table 1 above.

Next, the contents of the control will be described with reference to the flowcharts of FIGS. Here, Fig. 5 shows the contents of the control in the initial operation of the apparatus, the operation of the apparatus is started, the power lamp lights in Step R ₂ via step R _1, a main switch (Fig operation at step R ₃ Not shown)
There was lit Operation light Step R ₄ when turned ON, the process proceeds to step R _5. Next, in R _5, protective device (not shown) to determine normal or not, if successful, performs monitor display in Step R _6, an oil circulation pump (4) Step R ₇
After set to ON, in Step R ₈ above Modosutchi (SW1)
(SW3) is determined. When the mode switch (SW1) is ON, the mode is thermo-mode operation. When the mode switch (SW2) is ON, the mode is F / F mode. When the mode switch (SW3) is ON, the mode is I / F mode. Migrate each. In the judgment at the step R _5, if the state of the protection device is abnormal, performs abnormal output displayed in step R _9, waiting for the operation of the apparatus is to be and resets stopped in step R _10, R ₁₁ after turning off the abnormal output display, it has been made to return to step R _2.

Here, since the thermo mode operation is included in the F / F mode operation, it will be described later. First, the F / F mode operation will be described with reference to FIG.

First, the inlet oil temperature thermistor at step S ₁ (Th1)
Oil temperature T _O detected by air and air thermistor (Th2)
And enter the air temperature T _A, in step S _13, calculates the air temperature T _O and the inlet fluid temperature T temperature _A deviation _{ΔT (= T O -T A)} , in step S ₁₄ to S _22, From the value, it is determined which of the temperature zones (3-U) to (5-L) is currently located, and each temperature zone (3-U) to (5-L) is determined.
In response to L), at step S ₂₃ to S _32, an inverter (1
5) Output frequency f is + 30H from current frequency value
Control to increase or decrease z, + 20Hz, ..., -40Hz, -50Hz. In the temperature zones (0-U) and (0-L), the value of the output frequency f is maintained at the current frequency.

When the multi-step control is completed as described above, next, the stable region control for determining whether the control state is in the stable region is performed. That is, in step S _33, it is determined whether the temperature zone temperature deviation ΔT between the inlet oil temperature T _O and air temperature T _A is stable region (0-U) or (0-L), while re-set to the current frequency the output frequency f of the inverter (15) in step S ₃₄ if the stable area, unless the stable region, in step S _35, the number of times n that enters this step
Is counted, and in a step _S36 , it is determined whether or not the number n is 3 or less. When the number n is 3 or less, it is determined that no sufficient time to still change the operating conditions, while the current frequency the output frequency f of the inverter (15) in step S ₃₇ while keep, when the number of times n that is not determined to be the stable region exceeds 3, in step S _38, further change in temperature deviation ΔT is determined whether or not the increasing side of the frequency change, if an increase side Step S ₃₉
F in the f = f + 10 Hz, in step S ₄₀ if not increase side
= F-10 Hz respectively. That is, the deviation ΔT between the inlet oil temperature T _O and the air temperature T _A changes due to a change in the operating conditions, and the temperature zones (0-U) and (0-
L), the output frequency f of the inverter (15), that is, the operating frequency of the compressor (8) is not immediately changed. Change the temperature deviation ΔT to the temperature zone (0-
U) and (0-L).

Upon completion of the stable area controlled by the above, then in step S _41, the information from the external input signal, i.e. the main shaft portion thermistor in the machine tool (1) side (Th3), it is determined whether or not input. Then, the program shifts to the next control if not input, when the signal from the outside is input, processes the information content of the input signal in step S _42. That is, the external signals are (0000) to
It is determined which range is shown in the column of (1100). Thereafter, in step S _43, the setting of the frequency f of the inverter (15) in accordance with the set value of the second table. That is, when the temperature H of the main shaft portion (1a) rises over a predetermined rate of change ΔHo with respect to time, control delay occurs in the multi-step control, so that the cooling capacity of the refrigerating device (7) is reduced in advance. It is determined that the output frequency f needs to be increased, and the output frequency f of the inverter (15) is increased from the control value of the multi-step control as described above. If it decreases at the above rate,
In order to reduce the cooling capacity quickly, the inverter frequency f
Is controlled to decrease by a predetermined value.

When the control is ended by the incorporation of the external input signal, in step S _44, S _45, whether each f ≦ 120 Hz, to determine whether f <30 Hz, if any is YES, the compressor it is determined that has reached the temperature region for stopping the operation of (1), further after counting the number m in the step S _46, the number m in the step S ₄₇ it is determined whether or not 3 or less. And if the number m is 3 or less, the step
While avoiding the stop of forcibly held to the compressor (8) the frequency f to f = 30 Hz inverter (15) in S _47, by repeating the control, determination and stop region in step S _44, S ₄₅ If the operation is repeated three times, the compressor (8)
To stop. On the other hand, the determination in step S ₄₄ is f
If it is not ≦ 120 Hz, that is, if f is higher than 120 Hz, it is determined that the frequency f is excessive, and in step _S49 , f = 120
Set Hz, in the determination in step S _45, in the case of when that is more than 30Hz frequency f is not smaller than 30Hz, in step S ₅₀ to reset the frequency f remains in its current frequency.

Finally, in step _S51 , the output frequency f of the inverter (15) set by the above control is output to the compressor (8). In step _S53 , the sampling time is counted for 60 seconds to control the F / F mode operation. To end. The control of the return is made to be performed at step S _13.

FIG. 7 shows the control contents of the thermo mode operation,
The steps S ₁ '~S _53' are substantially corresponds to the control contents the F / F mode operation of Figure 6. That is, partial clogging step S ₁ except for the step S ₄₁ to S ₄₃ from the flow of FIG. 6
By to S ₄₀ and step S ₄₄ to S ₅₃ and Step S ₁ '~S _40' having the same content and step S ₄₄ '~S _53',
Control of the inverter frequency f is performed.

Next, the I / F control, will be described with reference to the flow chart of Figure 8, there is a command from the external signal whether determined in the step P _1, if an external command is output, the in step P ₂ The output frequency f of the inverter (15) is set based on Table 2. Then, to determine whether the stop command of the compressor (8) is output at step P _3,
If the stop command has not been output,
Waiting for the elapse willing 3 seconds P ₅ returns to step R ₂ in the flow of the FIG. 6. On the other hand, if the external command in the judgment at the step P ₁ is not output and the step P ₃
When the stop command of the compressor (8) in the determination is output, after stopping the operation of the migration to the compressor (8) in step P _4, it is made to proceed to step P ₅ I have.

Here, in the above flow, step S ₁₃ or S ₁₃ '
And the temperature deviation ΔT between the inlet oil temperature T _O and the air temperature T _A (= T _O −
T _A ), and then the temperature deviation ΔT is set to a predetermined set value.
Although so as to converge to T _S, in order to control as a control parameter only inlet oil temperature T _O instead of the temperature deviation ΔT is replacing the differential temperature ΔT in oil temperature T _O, the oil temperature T _O is Preset temperature
What is necessary is just to control so that it may converge to Ts. Therefore, FIG.
The seventh diagram of steps _{S 14 ~S 32, S 14 '} ~S 32', the thermistor (Th1) (or thermistor (Th1) and (Th
2)), the feedback control means (30) for controlling the output frequency of the inverter (15) based on the liquid temperature (or the temperature difference between the liquid temperature and the tuning reference temperature) is constituted, and FIG. in step P ₂ in step S _43, S ₄₃ 'or the eighth diagram of Figure 7, receives the output of the main shaft portion thermistor (thermal load state detection means) (Th3), the frequency of changing the operating frequency of the inverter (15) A changing means (31) is configured.

Further, in the above embodiment, the spindle thermistor (Th3) for detecting the temperature of the spindle (1a) of the machine tool (1) is provided as the thermal load state detecting means of the device (1).
a) a strain gauge or ammeter as a sensor for detecting the displacement V of a) or a current value I as a load of a spindle motor (not shown) as an actuator, and a change rate dV / dt of the displacement V;
Alternatively, the change rate dI / dt of the current I and a predetermined value ΔVo (for example, ΔVo =
From the relationship with about 0.5% / sec) or ΔIo (for example, about ΔIo = about 100 mA), ΔHo in Table 2 above is converted to ΔVo or ΔIo.
And changing the frequency f of the inverter (15) based on the zone in which the range of the displacement V or the current value I is divided into 10 steps above and below a predetermined standard value. Can be.

In particular, when the machine (1) is a machine tool (1), a change rate dA / dt and a predetermined value ΔAo (for example, a value of about ΔAo = 1 rpm) are obtained by using a tachometer for detecting the rotation speed A of the spindle as a thermal load state detecting means. ), The frequency f of the inverter (15) can be controlled based on the rotation speed A.

In the flow of the above embodiment, the step S ₁₃ or S ₁₃ '
When only the inlet oil temperature T _O is used as a control parameter instead of the temperature deviation ΔT shown in (1), the machine tool detected by the inlet oil temperature thermistor (coolant temperature detecting means) (Th1) by the feedback control means (30) (Equipment) The output frequency f of the inverter (15) is controlled in multiple stages so that the inlet oil temperature (liquid temperature) T _O of the cooling oil of (1) converges to a predetermined set value T _S. The operating frequency of the compressor (8) is adjusted. As a result, the amount of heat exchange between the refrigerant and the liquid in the evaporator (11) is adjusted so as to keep the liquid temperature constant.

At that time, during the constant control of the cooling oil temperature by such feedback control, the spindle speed A of the machine tool (1) is changed.
And the temperature H of the main shaft portion (1a), the displacement V of the main shaft portion (1a), and the like, change the rate of change to exceed a predetermined value. It is not possible to immediately follow only by adjusting the frequency f, and there is a possibility that a control delay or an unstable control state may occur. On the other hand, in the above embodiment, when such a large disturbance enters, the thermal load state is detected by the thermal load state detecting means, and the inverter frequency value by the feedback control means (30) is detected by the frequency changing means (31). fn
To the frequency value corresponding to the heat load at the time of the change (in the above embodiment, the step value of the inverter frequency is increased or decreased according to the magnitude of the change in the heat load).
Without delay of control by feedback control
It is possible to quickly follow the change in the state of the thermal load, thereby improving control accuracy while effectively preventing hunting.

In particular, as in the above embodiment, the air temperature sensor (reference temperature detecting means) detects the indoor air temperature (tuning reference temperature) T _{A at} which the liquid temperature T _{O is} to be tuned, and the cooling oil temperature T _O
Instead of the temperature difference ΔT between the cooling oil temperature T _O and the air temperature T _A (T _O −
T _A ), the feedback control, F / F control, I / F
By performing the control, even if the air temperature T _A changes, the temperature difference between the liquid temperature and the air temperature is kept within an appropriate range following the change. Therefore, there is an advantage that control delay and instability can be prevented while following changes in the environment such as indoor air, as compared with control using only the coolant temperature. In this case, the tuning reference target is not limited to the indoor air, and for example, the temperature of the machine tool (1) can be used as the tuning reference.

A mode switch (control mode selection means) (SW
1) to (SW3), the above-mentioned thermo mode, F / F mode, I
By selecting the control in the / F mode as an alternative, the oil control (cooling device) (2) can be controlled in a preferred control mode according to the type of equipment or the type of work in the machine tool (1). Operation can be controlled.

As in the above embodiment, when the temperature sensor (the spindle thermistor (Th3) in the above embodiment) is used as the thermal load state detecting means of the device (1), if the temperature of the device (1) rises for some reason, Although there is a predetermined time delay before the temperature rise causes a change in the temperature of the coolant, the temperature change of the device (1) is detected by the temperature sensor (Th3) as soon as possible, and the refrigerating capacity of the refrigerating circuit (14) changes in advance. Thus, it is possible to quickly respond to a change in the thermal load state of the device (1).

Although the embodiment is omitted, when a sensor that detects mechanical distortion of the operating section of the device (1) is used as the thermal load state detecting means, the force or temperature applied to the operating portion of the device (1) changes due to a change in temperature or temperature. The resulting distortion is detected as soon as possible.

Further, when a sensor for detecting a load applied to the actuator of the device (1) is used as the thermal load state detecting means, it is possible to predict that an increase in the load of the device (1) causes a temperature change or distortion of the operating portion. .

Similarly, when a sensor for detecting the number of revolutions of the main spindle in the case of the machine tool (1) is used as the thermal load detecting means, a change in the number of revolutions of the main spindle portion predicts a change in temperature or distortion. .

Here, in the above embodiment, the mode switches (SW1) to (SW3) as the control mode selection means are manually switched, but the control mode change pattern is determined in advance from the operation schedule of the machine tool or other equipment (1). If it is determined, a selection signal of the mode switches (SW1) to (SW3) may be incorporated in a program, and the selection may be made by the signal.

In this case, the interface circuit (16b) may be used as an external command signal output according to the heat load state of the device (1), for example, when a change in the heat load state such as the rotation speed of the machine tool is known from the operation pattern. ) Can be programmed, and a 4-bit signal based on Table 2 can be directly input to the interface circuit (16b).

In the above embodiment, the thermistor (Th1) as the coolant temperature detecting means is disposed on the inlet side of the cooling oil to the oil control (2), but the outlet side of the oil control (2), that is, to the machine tool (1). It may be arranged on the feeding side, and may be arranged at two places on the inlet side and the outlet side. However, the arrangement on the inlet side as described above has an effect that the influence of the control temperature on the fluctuation of the heat load due to the processing of the machine tool (1) can be suppressed.

In the above embodiment, step S in the flow of FIG.
₃₃ running to S ₄₀ in the stable area control, since to change the three operating frequency of the compressor (8) after performing a careful judgment by sampling against a change in temperature conditions, There is an advantage that the temperature can be prevented from frequently changing in a short cycle and stable control can be performed.

Then, in step S ₄₀ to S _43, in response to the input of an external signal, a thermistor (Th1), regardless of the signal (Th2),
Since the operating frequency f of the compressor (8) is forcibly controlled, it is possible to perform control corresponding to changes in important external conditions such as changes in the temperature of the main spindle (1a) of the machine tool (1). You can.

Further, in step S ₄₄ to S _50, provided a predetermined limit value in the operating frequency, with is not performed is operated at the limit value or more, when the instruction operation frequency is below the lowest possible value control Also, since the operation is stopped after the determination based on three samplings, the operation stoppage can be avoided as much as possible by restoring the operation state during that period, and the reliability of the compressor (8) can be improved. There are advantages.

Note that the device (1) to be cooled according to the present invention is not limited to the machine tool in the above embodiment, and it goes without saying that the device (1) can be applied to various industrial machines.

In the above embodiment, the case where oil is used as the cooling liquid has been described. However, similar effects can be obtained with various liquids such as water.

(Effect of the Invention) As described above, according to the invention of claim (1),
In a liquid cooling device for cooling a cooling liquid of equipment,
A compressor whose operation frequency is variably adjusted by an inverter is arranged in a refrigeration unit for cooling the liquid, and feedback control is performed so that the coolant temperature becomes constant. In the case of a change, the inverter frequency controlled by the feedback control is changed to a frequency value corresponding to the heat load at the time of the change in accordance with the heat load state. The control accuracy can be improved while preventing hunting without causing a control delay with respect to disturbance.

According to the invention of claim (2), the frequency of the inverter is adjusted so that the difference between the coolant temperature and the tuning reference temperature becomes constant instead of the cooling temperature in claim (1). Thus, the effects of the first aspect can be obtained while following changes in the environment.

According to the invention of claim (3), the control mode is switched between feedback control for converging the coolant temperature to the set value and feedback control and control for changing the inverter frequency value in the invention of claim (1). And control for changing the inverter frequency value in accordance with the heat load state, so that the operation can be appropriately performed by selecting a control mode according to the work content of the equipment. The effects of the invention (1) can be remarkably exhibited.

According to the invention of claim (4), the control mode is set so that the difference between the coolant temperature and the reference target temperature converges to a set value, and the feedback control and the inverter frequency in the invention of claim (1) are performed. Control to switch between the value change control and control to change the inverter frequency value according to the thermal load state is selected as an alternative. The effect of the invention of claim (2) can be remarkably exhibited.

According to the invention of claim (5), the above-mentioned claim (1),
In the invention of (2), (3) or (4), since the temperature sensor detects the thermal load state of the device, it is possible to detect an expected change before the temperature of the coolant changes. Therefore, the effect of improving the responsiveness in the inventions of claims (1) to (4) can be effectively exhibited.

According to the invention of claim (6), the above-mentioned claim (1),
In the invention of (2), (3) or (4), the thermal load state is detected by the sensor for detecting the mechanical distortion of the operating portion of the device, so that the temperature of the coolant is expected to change before the temperature changes. A possible change can be detected, and therefore, the same effect as the above-described invention (5) can be exerted.

According to the invention of claim (7), the above-mentioned claim (1),
In the invention of (2), (3) or (4), since the thermal load state is detected by the sensor for detecting the load applied to the actuator of the device, the temperature change of the operating portion and the distortion of the load are detected in advance. Therefore, the responsiveness can be further improved as compared with the invention of the above-mentioned claim (5) or (6).

According to the invention of claim (8), the above-mentioned claim (1),
In the invention of (2), (3) or (4), when the device is a machine tool, the thermal load state is detected by a sensor for detecting the number of revolutions of the main shaft. The distortion of the load can be detected in advance, and therefore, the responsiveness can be further improved as compared with the invention of claim (5) or (7).

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the invention of each claim. 2 to 9 show an embodiment of the present invention, FIG. 2 is an overall configuration diagram, FIG. 3 is a front view of a switch panel, FIG. 4 is an explanatory diagram showing a temperature zone of multi-step control, FIG. 5 is a flowchart showing control contents at the time of starting the apparatus,
FIG. 6 is a flowchart showing the control content of the F / F mode operation, FIG. 7 is a flowchart showing the control content of the thermo mode operation, and FIG. 8 is a flowchart showing the control content of the I / F mode operation. . Fig. 9 shows the conventional compressor ON
FIG. 4 is a characteristic diagram illustrating a temperature change characteristic of a coolant by an OFF control. (1) ... machine tool (equipment), (3) ... oil circulation circuit (liquid circulation circuit), (8) ... compressor, (9) ... condenser, (10) ... capillary (pressure reducing mechanism) ), (11) evaporator, (14) refrigeration circuit, (15) inverter,
(30) ... feedback control means, (31) ... frequency changing means, (Th1) ... inlet oil temperature thermistor (liquid temperature detecting means), (Th2) ... air temperature thermistor (reference temperature detecting means), ( Th3): Thermistor of the spindle part (thermal load state detecting means), (SW1) to (SW3): Mode switch (control mode selecting means).

Claims (8)

(57) [Claims] A liquid circulation circuit (3) for circulating a cooling liquid of a device (1), while a compressor (8), a condenser (9),
In the liquid cooling apparatus provided with a refrigerating circuit (14), which is sequentially connected to a pressure reducing mechanism (10) and an evaporator (11) for cooling the liquid in the liquid circulation circuit (3) by heat exchange with a refrigerant. An inverter (15) for variably adjusting an operation frequency of the compressor (8); a liquid temperature detecting means (Th1) for detecting a temperature of a coolant in the liquid circulating circuit (3); (Th1) feedback control means (30) for controlling the output frequency of the inverter (15) so that the coolant temperature converges to a set value, and heat for detecting the thermal load state of the device (1). Load state detecting means,
When the output of the heat load state detecting means is received and the change in the heat load of the device (1) becomes a predetermined value or more, the frequency of the inverter (15) is increased from the frequency value controlled by the feedback control means (30). A temperature control device for a liquid cooling device, comprising: frequency changing means (31) for changing to a frequency value corresponding to a heat load when the device (1) changes. 2. A liquid circulation circuit (3) for circulating a cooling liquid of the equipment (1), while a compressor (8), a condenser (9),
In the liquid cooling apparatus provided with a refrigerating circuit (14), which is sequentially connected to a pressure reducing mechanism (10) and an evaporator (11) for cooling the liquid in the liquid circulation circuit (3) by heat exchange with a refrigerant. An inverter (15) for variably adjusting an operation frequency of the compressor (8); a liquid temperature detecting means (Th1) for detecting a temperature of a coolant in the liquid circulation circuit (3); A reference temperature detecting means (Th2) for detecting a temperature of a tuning reference object which is a reference for tuning, and receiving the outputs of the liquid temperature detecting means (Th1) and the reference temperature detecting means (Th2), Feedback control means (30) for controlling the output frequency of the inverter (15) so that the temperature difference from the temperature converges to the set value;
A thermal load state detecting means for detecting the thermal load state of the device, and receiving the output of the thermal load state detecting means, and when the change in the thermal load of the device (1) becomes a predetermined value or more, the frequency of the inverter (15) is changed. A liquid cooling device comprising: frequency changing means (31) for changing a frequency value controlled by the feedback control means (30) to a frequency value corresponding to a heat load when the equipment (1) changes. Temperature control device. 3. A compressor (8), a condenser (9), a liquid circulation circuit (3) for circulating a cooling liquid of the equipment (1).
In the liquid cooling apparatus provided with a refrigerating circuit (14), which is sequentially connected to a pressure reducing mechanism (10) and an evaporator (11) for cooling the liquid in the liquid circulation circuit (3) by heat exchange with a refrigerant. An inverter (15) for variably adjusting an operation frequency of the compressor (8); a liquid temperature detecting means (Th1) for detecting a temperature of a coolant in the liquid circulating circuit (3); (Th1) feedback control means (30) for controlling the output frequency of the inverter (15) so that the coolant temperature converges to a set value, and heat for detecting the thermal load state of the device (1). Load state detecting means,
Frequency changing means (31) for changing the frequency of the inverter (15) based on the heat load state of the device (1) in response to the output of the heat load state detecting means and an inverter (31) in response to an external command signal. 15) The control mode of the frequency is controlled by the control mode using only the feedback control means (30) and the control by the feedback control means (30).
When the change in the heat load of the device (1) detected by the heat load state detecting means exceeds a predetermined value, the frequency changing means (31)
The control mode for switching the control for changing the frequency of the inverter (15) from the frequency value by the feedback control means (30) to the frequency value corresponding to the heat load at the time of change, and the control mode using only the frequency changing means (31). A temperature control device for a liquid cooling device, comprising: a control mode selection means (17) for selecting the temperature uniformly. 4. A compressor (8), a condenser (9), a liquid circulation circuit (3) for circulating a cooling liquid of the equipment (1).
In the liquid cooling apparatus provided with a refrigerating circuit (14), which is sequentially connected to a pressure reducing mechanism (10) and an evaporator (11) for cooling the liquid in the liquid circulation circuit (3) by heat exchange with a refrigerant. An inverter (15) for variably adjusting the operating frequency of the compressor (8); a liquid temperature detecting means (Th1) for detecting the temperature of the coolant in the liquid circulation circuit (3); A reference temperature detecting means (Th2) for detecting a temperature of a tuning reference object serving as a reference to be output; receiving outputs of the liquid temperature detecting means (Th1) and the reference temperature detecting means (Th2); Feedback control means (30) for controlling the frequency of the inverter (15) so that the temperature difference between the two converges to a set value; heat load state detection means for detecting the heat load state of the device (1); Receives the output of the load state detection means and (1) a frequency changing means (31) for changing the frequency of the inverter (15) based on the thermal load state; and a control mode of the frequency of the inverter (15) in response to an external command signal. When the change in the heat load of the device (1) detected by the heat load state detecting means exceeds a predetermined value while performing the control mode by only the control mode (30) and the control by the feedback control means (30), the frequency changing means ( 31) A control mode in which the frequency of the inverter (15) is switched from a frequency value by the feedback control means (30) to a frequency value corresponding to the heat load at the time of change, and a control mode by only the frequency changing means (31). And a control mode selecting means (17) for selectively selecting the temperature control device. 5. The apparatus according to claim 1, wherein said thermal load state detecting means is a temperature sensor (Th3) for detecting a temperature of an operating part of the device (1). The control device of the liquid cooling device according to (4). 6. The apparatus according to claim 1, wherein said thermal load state detecting means is a sensor for detecting a mechanical distortion of an operating portion of the device (1). The control device of the liquid cooling device according to the above (1). 7. The apparatus according to claim 1, wherein said thermal load state detecting means is a sensor for detecting a load on an actuator of the device. Control unit for liquid cooling device. 8. The apparatus according to claim 1, wherein said thermal load state detecting means is a sensor for detecting a rotation speed of a main shaft when the device (1) is a machine tool.
The control device for a liquid cooling device according to (3) or (4).