JP3217030B2 - Cold air supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold air supply device used for blowing cold air onto a processing object for performing cold air processing, and more particularly, to a pre-cooling preparation required for resuming operation after a temporary stop state. The present invention relates to a cool air supply device for reducing time.

[0002]

2. Description of the Related Art Cutting, grinding and the like by a machine tool are performed while supplying cool air and oil to a work. The cold air supply device used to blow cold air onto the work is configured to use a mechanical refrigerator to cool and dehumidify the compressed air to form cold air, and to blow this cold air from the nozzles to the work area of the work. ing. Cold air supply equipment used for cold air processing of such machine tools
For example, it is disclosed in JP-A-10-86036.

In the cold air machining operation, as shown in FIG. 6, after starting up the machine tool and the cold air supply device (time T11), the cool air blown out from the cold air supply device is cooled to a predetermined temperature. (Time T1
2), need to start. In order to reduce the waste time of the work caused by the pre-cooling preparation time (t) of the cold air supply device, for example, only the cold air supply device is first activated by a weekly timer before the operation time in advance. It is good.

[0004]

However, the pre-cooling preparation time of the cold air supply device is required not only at the time of operation or at the start of operation. For example, since processing is temporarily stopped during breaks such as lunch, cold air is not required,
The cold air supply device also stops at the same time (time T13 in FIG. 6).
In addition, the cold air supply device also stops when processing is temporarily stopped for work setup change or maintenance and inspection of the machine tool. Therefore, only the pre-cooling preparation using the weekly timer cannot cope with the pre-cooling preparation necessary for restarting the operation after such a temporary stop.

[0005] It is conceivable that the timer setting is made finer to suppress the dead time caused by the pre-cooling preparation after the temporary suspension. However, for unpredictable irregular temporary stop (time T15 in FIG. 6) due to unexpected damage or breakage of the consumables such as blades and grindstones, and failure of the machine tool itself, pre-cooling preparation using a timer. Can not cope.

[0006] Of course, if the continuous operation is performed without stopping the cold air supply device, the pre-cooling preparation time associated with the temporary stop is unnecessary, but this is not practical because the cool air is wasted and energy loss occurs. .

[0007] In view of the above, the object of the present invention is to provide:
It is an object of the present invention to propose a cool air supply device capable of reducing a waste time of a processing operation by shortening a pre-cooling preparation time associated with a temporary stop.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a refrigerator for cooling dehumidified compressed air, and a cool air for blowing the compressed air cooled by the refrigerator toward a cooling object. A cold-air supply device having a blowing unit, wherein a flow-rate adjusting unit that limits a flow rate of the cool air blown out from the cold-air blowing unit to a standby operation flow rate that is zero or smaller than a flow rate in a normal operation during a standby operation. It is characterized by:

In the cool air supply device according to the present invention, the flow of the cool air from the cool air blowing unit is prevented by the flow rate adjusting means during the standby operation, that is, the temporary stop when the cool air is not required. Alternatively, the flow rate of the cool air to be blown out is reduced more than the flow rate of the cool air in the normal operation, which is the processing.

When the blowing of the cool air is stopped by the flow control means, the compressed air does not flow through the compressed air cooling section of the refrigerator, that is, the refrigerator is operated without load.
Therefore, the pre-cooling preparation time required for restarting the operation can be reduced as compared with the conventional case where the cold air supply device is completely stopped. Further, compared to a case where the continuous operation is performed without temporarily stopping the cool air, waste of the cool air and energy loss accompanying the cool air can be avoided.

On the other hand, when the flow rate of the cool air is reduced by the flow rate adjusting means, unlike the case where the supply of the cool air is completely stopped, the state in which the cool air continues to flow through the cool air supply passage though a small amount is maintained. Is done. Therefore, a portion such as a pipe constituting the cold air supply path does not rise to the ambient temperature, and is maintained in a certain cooling state. Therefore, when the operation is resumed after the standby operation, the cooling air in a certain cooling state may be reduced to a predetermined cooling temperature, so that the pre-cooling preparation time can be shortened, and the waste of machining time can be suppressed accordingly. In addition, since the flow rate of the cool air during the standby operation is small, waste of the cool air and the energy loss accompanying the cool air can be suppressed as much as possible in a case where the cool air is continuously operated without being temporarily stopped.

Here, when the blowing of the cool air is stopped, the flow rate adjusting means includes an on-off valve arranged in a cool air supply passage communicating the compressed air cooling section of the refrigerator and the cool air blowing section. It can be configured.

[0013] In this case, in order to avoid the adverse effects caused by closing the expansion valve of the refrigerant circuit accompanying the no-load operation of the refrigerator, the compressed air cooling unit and It is desirable to provide a bypass which can bypass the expansion valve connected to the upstream side of the compressed air cooling unit, and open the bypass in conjunction with the closing operation of the on-off valve.

On the other hand, when the flow rate of the cool air is to be reduced, the flow rate adjusting means includes a flow control valve disposed in a cool air supply passage communicating the compressed air cooling section of the refrigerator and the cool air blowing section. It can be configured.

Also in this case, an on-off valve is provided in place of the flow control valve, and at least one of the on-off cycle of the on-off valve and the on-off time ratio in one on-off cycle is controlled, whereby the standby is achieved. An operating flow rate may be defined.

As a command for switching the cold air supply device to the standby operation at the time of a temporary stop, a state signal of the machine to be cooled which is generated on the side of the machine to be cooled can be used. Instead, the standby operation may be switched by a manual operation input.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a cold air supply apparatus according to the present invention.

(First Embodiment) FIG. 1 is a system diagram of a cool air supply system using the cool air supply device of the present embodiment. The cold air supply device 1 of the main cooling includes a compressed air source 2 composed of a compressor or the like, an air dryer 3 with a drain for dehumidifying the compressed air supplied from the compressed air source 2, and further dehumidifying the compressed air after dehumidification. Adsorption type dehumidifier 4 and this adsorption type dehumidifier 4
A cooler 51 of the refrigerator 5 for cooling the compressed air dehumidified by the above, and a cool air nozzle for blowing the cool air obtained through the cooler 51 to the processing portion of the work W processed by the processing machine M 6 is provided. Such a configuration,
It is basically the same as a commonly used cold air supply device.

In the cold air supply device 1 of this embodiment, in addition to the above configuration, a flow control valve 8 is interposed in a cold air supply passage 7 that communicates between the cooler 51 and the cold air nozzle 6. . The flow control valve 8 is, for example, a motor valve, and a drive signal 91 from a valve drive circuit 91 included in the device control circuit 9.
Driven according to S, the flow rate of the cool air passing through the cool air supply path 7 is adjusted. In the present example, the air is held in the fully open state during the normal operation, and is throttled so that a very small amount of cold air flows during the standby operation, which will be described later, as compared with the normal operation.

The main cooling valve drive circuit 91 includes a machine tool M
, A state signal S1 including a pause signal for switching the machine tool to a pause state is input. The temporary stop signal S1 includes the machine tool M
Status signal indicating an abnormal state, setup change, preparation, or the like. A standby mode changeover switch 93 is provided on the operation panel 92. When the switch 93 is operated, a temporary stop signal 93S is supplied to the valve drive circuit 91.

FIG. 2 is a timing chart showing a cold air supply operation of the cool air supply device 1. The cold air supply operation will be described also with reference to this drawing. Machine tool M in operation stop state
Is activated at time T1, the cold air supply device 1 is also activated in conjunction therewith. At the time of startup, each part such as the cold air nozzle 6 and the cold air supply path 7 of the cold air supply device 1 is in a normal temperature state (for example, 25 degrees Celsius).

When the cool air supply device 1 is started, the cool air blown out from the cool air nozzle 6 is still at room temperature, and is cooled by the refrigerator 5 over time to reach a target temperature (for example, Celsius). (-30 degrees). After the start, the flow control valve 8 is kept in a fully open state, so that the air having a flow rate of 100% is blown out from the cool air nozzle 6.

At a time T2 when a predetermined precooling preparation time t has elapsed from the start at the time T1, the temperature of the cool air blown from the cool air nozzle 6 reaches the target temperature. Therefore, the actual machining operation starts from this time T2.

Thereafter, at time T3, for example, when the machine tool M is temporarily stopped by lunch, the cold air supply device 1
Switches to the standby mode instead of switching to the temporary stop state. That is, the state signal S1 indicating the temporary stop state of the machine tool M is input to the valve drive circuit 91, and the valve drive circuit 91 drives the flow control valve 8 to reduce the supply flow rate of the cool air to the minute flow rate (x in FIG. 2). % Flow rate).

In the standby operation mode, since the cool air continues to flow through the cool air supply path of the cool air supply device 1 at a small flow rate, the temperature of the portion such as the cool air nozzle 6 does not rise to the normal temperature state. Instead, it is kept in a predetermined cooling state.

Next, at time T4, when the machine tool W switches from the temporary stop state to the re-operation state, a state signal S1 indicating this switch is supplied to the valve drive circuit 91, and the flow control valve 8 is fully opened. The state is switched to the state, and the cold air supply device 1 returns to the normal operation state from the standby state. At this time,
Since each part of the cool air supply device 1 such as the cool air nozzle 6 is cooled to a certain extent by the minutely flowing cool air, the pre-cooling preparation time t from the normal temperature state to the target cooling state is reached.
During the short pre-cooling preparation time ta, it is possible to cool the cooling air from the cold air nozzle 6 to the target temperature (-30 degrees Celsius).

Therefore, in the cold air supply device 1 of this embodiment, the pre-cooling preparation time can be reduced as compared with the conventional device when the machine tool M is restarted after the temporary stop, and the machining work after the stop is correspondingly reduced. Can be started earlier and work efficiency can be improved. Further, since the cool air blown out at the time of the temporary stop has a minute flow rate, it is possible to minimize the energy loss due to unnecessary cool air blowing.

It is to be noted that the hand-operated switch 93
By operating, the cold air supply device 1 can be switched to the standby operation at any time.

(Second Embodiment) FIGS. 3 and 4 show a schematic configuration of a cool air supply device according to a second embodiment of the present invention and a timing chart of its operation. The cool air supply device 10 of the present embodiment is different from the cool air supply device 10 in that the open / close valve is opened and closed instead of the flow control valve in order to flow a small amount of cool air during the standby operation. The configuration is the same as that of the cold air supply device 1 of the first embodiment. Therefore, corresponding parts are denoted by the same reference numerals, and description of those common parts will be omitted.

The cold air supply device 10 of the present embodiment is different from the control circuit 9 having the flow rate control valve 8 and the valve drive circuit 91 in that an on-off valve 18 of an electromagnetic type or the like and a valve for driving the on-off valve 18 are used. And a control circuit 19 including a drive circuit 191.

The valve drive circuit 191 for the on-off valve 18 can hold the on-off valve 18 in a fully open state and can drive the on-off valve 18 at a predetermined on-off cycle based on a built-in timer function. In this example, in response to the state signal S1 supplied from the machine tool M, the valve drive circuit 191 sets the on-off valve 18 to one of a fully open state and an intermittent open / close drive state at a constant cycle. Switch. Also, when the manual operation switch 93S is input, the switching valve 18 is switched from the fully open state to the intermittent opening and closing drive state. When the opening / closing valve 18 is in the intermittent opening / closing drive state, the opening / closing cycle and
A small amount of cold air determined according to the open / close duty ratio in one open / close cycle flows and is blown out from the cool air nozzle 6.

In operation, when the operation of the machine tool M is temporarily stopped at the time T3, the on-off valve 18 is opened and closed at a predetermined duty ratio under the control of the valve drive circuit 191 in conjunction therewith. Is repeated. In the illustrated case, the ratio of the closing time tc is larger than the opening time to. By repeatedly opening and closing the on-off valve 18 in this manner, the flow rate of the cool air flowing therethrough is reduced to a minute flow rate compared to the flow rate during normal operation. As a result, the pre-cooling preparation time ta1 required at the time of restarting the operation is significantly shorter than the time t required in a completely stopped state. Therefore, the same operation and effect as those of the first embodiment can be obtained.

The open / close cycle and open / close duty ratio of the open / close valve 18 are properties to be determined in consideration of the blowing temperature, the required air volume, and the like in each cold air supply device. Of course, the valve drive mechanism 191 may be provided with a mechanism for changing the opening / closing cycle and the opening / closing duty ratio so that these can be arbitrarily switched.

(Third Embodiment) Here, in the above-described cold air supply device 10, the open / close valve 18 is opened and closed at a constant cycle during the standby operation, so that a small amount of cold air is caused to flow. Alternatively, the on-off valve 18 may be switched to the fully closed state, and the refrigerator 5 may be set to the no-load operation state.
Also in this state, the pre-cooling preparation time required at the time of returning to the normal operation can be reduced as compared with the case where the cold air supply device 10 is completely stopped. In addition, in this case, unnecessary cool air is not blown out, so that there is an advantage that energy loss is extremely small.

However, when the refrigerator 5 is operated under no load,
In a commonly used refrigerant circuit of a refrigerator, an expansion valve operates so as to close, causing adverse effects such as a decrease in evaporation pressure and deterioration of oil return to the compressor. Therefore, in order to avoid such adverse effects, it is desirable to add a bypass circuit to the refrigerant circuit as shown in FIG.

That is, as shown in FIG.
Is basically provided with a refrigerant circuit having the same configuration as a normal refrigerant circuit. The refrigerant after cooling the compressed air in the cooler 51 is returned to the compressor 53 via the accumulator 52 to be compressed and condensed. After being liquefied through a vessel 54, it is supplied to an expansion valve 56 via a drier 55, expanded and cooled, and supplied to a cooler 51.

In this embodiment, a bypass circuit 57 is provided which can communicate between the expansion valve 56 and the cooler 51 and between the cooler 51 and the accumulator 52. A capacity adjusting valve 58 is interposed in the bypass circuit 57. The bypass circuit 57 can also be configured using a capillary tube 59 as shown by imaginary lines in the figure.

When the on-off valve 18 is closed and the cold air supply device 10 is switched to the standby operation, and the refrigerator 5 enters the no-load operation state, a certain amount or more of the refrigerant bypasses the expansion valve and circulates. As a result, it is possible to avoid a decrease in the evaporation pressure and an increase in the return of oil to the compressor.

[0039]

As described above, the cool air supply device of the present invention is switched to the standby operation when the system incorporating the cool air supply device is temporarily stopped, so that the minute amount of the cool air continues to flow. . Alternatively, the supply of the cool air is stopped to switch the refrigerator to the no-load operation state. Therefore, according to the present invention, the pre-cooling preparation time of the cold air supply device at the time of re-operation after the suspension of the system can be shortened, and the waiting time at the time of restarting the operation of the entire system can be reduced accordingly. Operation efficiency can be improved.

Also, unlike the case where the waiting time due to the pre-cooling preparation time is shortened by starting only the cold air supply device early by using a timer, it is possible to cope with a sudden or instantaneous suspension of the system. The pre-cooling preparation time after such a temporary stop can be shortened. In addition, since the cool air is not flowed at the same flow rate as in the normal operation, it is possible to suppress unnecessary blowing of the cool air and to reduce the energy loss.

[Brief description of the drawings]

FIG. 1 is a system diagram of a cool air supply system including a cool air supply device according to a first embodiment to which the present invention is applied.

FIG. 2 is a timing chart of the operation of the cold air supply device of FIG.

FIG. 3 is a system diagram of a cool air supply system including a cool air supply device according to a second embodiment to which the present invention is applied.

FIG. 4 is a timing chart of the operation of the cool air supply device of FIG. 3;

FIG. 5 is a schematic circuit diagram showing a refrigerant circuit of a refrigerator in a modification of the cold air supply device of FIG.

FIG. 6 is an explanatory diagram showing a problem of a conventional cool air supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cold air supply apparatus 2 Compressed air source 3 Air dryer 4 Adsorption type dehumidifier 5 Refrigerator 51 Cooler (compressed air cooling part) 57 Bypass circuit 6 Cold air nozzle (Cold air blowing part) 7 Cold air supply path 8 Flow control valve 9 Control circuit 91 Valve drive circuit 92 Operation panel 93 Hand operation switch 93S Temporary stop signal S1 State signal M Machine tool W Work

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25D 1/00 B23Q 11/10

Claims (7)

(57) [Claims] 1. A cold air supply device having a refrigerator that cools compressed air and a cool air blowing unit that blows out the compressed air cooled by the refrigerator toward a cooling target, wherein the cold air blown from the cold air blowing unit is provided. A cool air supply device comprising a flow rate adjusting means for limiting a flow rate to a standby operation flow rate during standby operation so as to be zero or smaller than a flow rate during normal operation. 2. The flow control device according to claim 1, wherein the flow control means includes a flow control valve disposed in a cool air supply passage communicating the compressed air cooling section of the refrigerator and the cool air blowing section. Cold air supply device. 3. The apparatus according to claim 1, wherein the flow rate adjusting means includes an on-off valve arranged in a cold air supply path that connects the compressed air cooling section of the refrigerator and the cold air blowing section. Cold air supply device. 4. The cool air supply device according to claim 3, wherein the standby operation flow rate is defined based on at least one of an open / close cycle of the open / close valve and an open / close time ratio in one open / close cycle. 5. The refrigerant circuit according to claim 3, wherein a refrigerant circuit that circulates refrigerant through a compressed air cooling unit of the refrigerator is connected to the compressed air cooling unit and an upstream side of the compressed air cooling unit. A cool air supply device comprising a bypass passage for circulating a predetermined amount of refrigerant by bypassing a valve. 6. The apparatus according to claim 1, wherein the flow rate adjusting means is drive-controlled based on a state signal of the machine tool generated on the side of the machine tool to be cooled. A cold air supply device. 7. The cool air supply device according to claim 1, wherein the flow rate adjusting means is drive-controlled based on a manual operation input.