JPH09136244A - Spindle temperature controlling method and device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a temperature of a spindle device in a machine tool with precision by means of an easily controllable device provided with a simple structure. SOLUTION: In advance, cool liquid and hot liquid are prepared in separate tanks 1, 7, and these liquids are supplied to a main spindle device alternately via valves Sol. 1, Sol. 2 so as to carry out lubrication and cooling of the spindle device. Temperature Tr of the returned liquid, which is supplied to the spindle device and warmed, is compared with a target temperature Tm by means of a controller, and on the basis of the order of time ratio table, an ON/OFF time ratio of each of the valves connected to the cool liquid and the hot liquid is controlled, so that the temperature of the spindle is always synchronized with the target temperature Tm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the temperature of a cooling liquid supplied to lubricate and cool a spindle device of a machine tool so as to synchronize the spindle temperature with a target temperature. The present invention relates to a control method and device.

[0002]

2. Description of the Related Art A temperature gradient around a circulating oil circulation device is kept constant by controlling the temperature of the circulating oil supplied to the circulating oil circulation device in synchronization with the changing atmospheric temperature to control the temperature of the circulating oil circulation device. For the purpose of eliminating the thermal strain of each part of the machine body caused by the above-mentioned thermal displacement, the preset low temperature hydraulic oil and high temperature hydraulic oil of the same quality are input as the detection signal values of atmospheric temperature and circulating oil temperature, respectively. An "oil temperature control device", in which the working oil that has been mixed and passed through the pumping ratio control valve operated by the processed control means and supplied to the circulating oil circulation device, is disclosed in Japanese Patent Publication No. 46-16216. ing.

Further, in a cooling system for maintaining a heat-generating facility at a constant temperature, a low-temperature liquid and a high-temperature homogeneous liquid are supplied to each heat-generating liquid, a cooling liquid temperature obtained by mixing the liquids, and the mixed liquid to the heat-generating equipment. However, the liquid temperature after cooling the same equipment is mixed with the detected temperature signal value and the target temperature signal value into a predetermined mathematical expression in a predetermined mathematical expression, and the detected temperature values are mixed at a ratio obtained to obtain an appropriate temperature. JP-A-3-39881 discloses that the cooling liquid is used to cool the equipment.

[0004]

In any of the above-mentioned prior arts, a liquid having a required temperature is obtained by mixing two homogeneous liquids having different temperatures, and the liquid is supplied to a heating element to generate the same heating element. This is a technique for cooling and maintaining the temperature of the heating element at a target value. In other words, how to obtain a liquid with an appropriate (required) temperature for the heating element is the goal of technological development. In order to solve this problem, an expensive pumping ratio control valve having a large number of temperature detecting means or a complicated structure is necessary, or a ratio based on a predetermined mathematical expression whose signal value of the temperature detecting means is an element is used. Therefore, expensive parts such as a servo valve for mixing the cold and hot two liquids and a complicated controller are required.

Further, in the well-known spindle temperature control means which does not adopt the above-mentioned method / apparatus, based on the feedback control, a liquid temperature adjusting (cooler) means provided in the circulation path of the cooling liquid to be supplied to the apparatus is provided. , ON / OFF is performed so that the detected value of the spindle temperature is synchronized with the target temperature. With this method, the cooling capacity fluctuation of the cooler during ON / OFF switching tends to cause cooling delay or supercooling of the spindle temperature, and the fluctuation range of thermal displacement of the spindle temperature becomes large. There are problems.

Therefore, the present invention solves the above-mentioned problems inherent in the conventional cold / warm lubricating oil mixing system and apparatus, has a simple structure, is easy to control, is economical, and has a fluctuation range of thermal displacement of the spindle. It is an object of the present invention to provide a spindle temperature control method and apparatus for a machine tool that is extremely small.

[0007]

The present invention has the following components in order to achieve the above object. (1) In a spindle temperature control method for a machine tool, in which a cooling fluid having a predetermined flow rate is externally supplied to a spindle device of a machine tool so that the temperature of the spindle is synchronized with a target temperature, the cooling is performed to a predetermined temperature lower than the target temperature. The stored cooling liquid is stored in the first tank, and the heated cooling liquid is supplied to the spindle device and stored in the second tank. The cooling liquid of the first tank and the cooling liquid of the second tank are stored. Are alternately supplied to the spindle device, and the supply time of the cooling liquid of the first tank and the cooling liquid of the second tank within a predetermined unit time are adjusted so that the temperature of the spindle synchronizes with the target temperature. A spindle temperature control method for machine tools that controls the ratio to the supply time.

(2) In a spindle temperature control device for a machine tool, which supplies a cooling fluid of a predetermined flow rate to the spindle device of a machine tool from the outside so as to synchronize the temperature of the spindle with a target temperature, a predetermined temperature lower than the target temperature. A first tank that stores a cooling liquid cooled to a temperature; a second tank that collects and stores the cooling liquid that has been supplied to the spindle device and warmed;
Cooling liquid supply means for alternately supplying the cooling liquid of the tank and the cooling liquid of the second tank to the main spindle device, and the first in a predetermined unit time so that the temperature of the main spindle is synchronized with the target temperature. A spindle temperature control device for a machine tool, comprising: a control unit that controls a ratio of a supply time of a cooling liquid of a tank and a supply time of a cooling liquid of the second tank.

(3) The cooling liquid supply means is the first
The conduit from the tank and the conduit from the second tank are merged into a single conduit, and a pump means is provided in the single conduit to connect to a spindle device, and the first tank to the A first on-off valve is provided between the merging pipe line and a second on-off valve between the second tank and the merging pipe line. When the first on-off valve is open, the second on-off valve is Closed,
The second opening / closing valve is configured to be opened when the first opening / closing valve is closed, and the control means controls the first, second and third units within a predetermined unit time so that the temperature of the spindle is synchronized with the target temperature. The spindle temperature control device for a machine tool according to (2) above, which is configured to control the opening / closing time ratio of the second opening / closing valve.

[0010]

Function: Two cooling liquids of the same quality of cold, warm and different temperature are prepared, and cooling, hot, cold and hot are alternately cooled in respective pipes for supplying the cooling liquid to the spindle device. While feeding the liquid, the supply time ratio of each cooling liquid within a unit time is controlled to be long or short in accordance with the spindle temperature, so that the spindle temperature is synchronized with the target temperature.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method and apparatus for controlling a spindle temperature of a machine tool of the present invention will be described below with reference to the drawings. Each member constituting this embodiment is at the time of the application of the present invention. Since various modifications are possible within the technical level of the art, the invention is limited to the gist of the present invention based on only the configuration of the embodiment described below without showing any special reason. Don't

FIG. 1 is a block diagram of a preferred embodiment of an apparatus for carrying out the method for controlling the spindle temperature of a machine tool according to the present invention, and FIG. 2 is a solenoid valve supply Sol.
3 shows an example of an ON / OFF time ratio table, and FIG. 3 shows an example of a control signal for turning ON / OFF the solenoid opening / closing valves Sol.1 and Sol.2.

In FIG. 1, the first one whose periphery is covered with a heat insulating material
The tank 1 is filled with a cooling liquid 3 which also serves as lubricating oil, and the cooling liquid 3 is pumped up by a pump 5 provided outside the tank, flows through a cooler of a cooler 7, and is returned to the inside of the first tank 1 again. Liquid temperature Tc is constantly circulated through the circulation line.
Has been maintained. That is, the cooler 7 is controlled by the control signal output from the controller 11 that receives the signal value from the first temperature detector 9 that detects the liquid temperature Tc of the cooling liquid 3 flowing in the circulation pipe. When the liquid temperature of the cooling liquid 3 in one tank 1 exceeds a predetermined value, the compressor operates to cool the cooling liquid 3, and when the liquid temperature of the cooling liquid 3 falls below the predetermined value, the operation is stopped, and the cooling liquid 3 Through the circulation line without cooling.

The second tank 13 is juxtaposed with the first tank 1. The tank 13 communicates with the first tank 1 through a communication pipe provided at a high level to cool and lubricate the spindle device 15. Then, the warmed cooling liquid 3 is collected and stored in the second tank 13, overflows when the tank 13 is filled with the cooling liquid 3 and exceeds the level, and the excess cooling liquid 3 is transferred to the first tank through the communication pipe. It flows into the tank 1 side. Cooler 7 in the first tank 1
Is provided to cool the above-mentioned inflow cooling liquid, etc.
This is because the cooling liquid 3 in the tank 1 is always maintained at the temperature Tc. The oil pan 19 and the second tank 13 of the spindle device 15
A second temperature detector 17 for detecting the return (cooling) liquid temperature Tr is attached to the return liquid pipe connecting the and, and its output signal is input to the controller 11.

In the vicinity of the bottoms of the first and second tanks 2 and 13, an electromagnetic opening / closing (first opening / closing) valve Sol.1 and an electromagnetic opening / closing (second opening / closing) valve Sol. .2 is opened, and the respective downstream pipelines of the solenoid on-off valves Sol.1 and Sol.2 are mergers.
A single unit is connected to the suction port of the constant discharge pump 23 at 21 and the discharge port of the pump 23 is connected to the main shaft device 15 to supply the cooling liquid 3 to the bearing portion of the main shaft constituting the main shaft device. . Here, as is clear from FIG. 1, the solenoid on-off valve
Sol.1 is closed when the solenoid is turned on and opened when it is turned off. Solenoid shut-off valve Sol.2 opens when the solenoid is turned on and closes when it is turned off. The cooling liquid 3, which is continuously supplied to the main spindle device 15 and lubricated and cooled to heat the bearing members and the like due to the high speed rotation of the main spindle, is warmed and flows down and stays in the oil pan 19 arranged at the bottom of the device. . As described above, the bottom of the oil pan 19 of the main spindle device 15 is provided with a return liquid conduit communicating with the second tank 13.

In the above description, the cooling liquid 3 in the first and second tanks is the electromagnetic on-off valves Sol.1, Sol.2, the confluencer 21, the constant discharge pump 23, the main shaft device 15, the oil pan 19, and the first. 2 tanks 13
It will be understood that, through the above, a part thereof forms a circulation path such as flowing into the first tank 1.

In the figure, reference numeral 25 denotes a bed of a machine tool. A third temperature detector 27 is attached to the bed 25, a target temperature Tm is detected and output from the detector 27 and is input to the controller 11. In the present embodiment, the target temperature Tm is separated from the spindle device 15 and the machining region to detect the temperature of the machine body, for example, the bed, which is stable in terms of temperature conditions. However, the target temperature Tm may be the atmospheric temperature or may be another specific temperature.

When the temperature of the bed 25 or the atmospheric temperature is adopted as the target temperature Tm, the temperature fluctuates with time. In other words, maintaining the spindle temperature at the target temperature Tm means controlling the spindle temperature by following the temperature that fluctuates with time. In addition, the spindle temperature is set to the target temperature T
It is not necessary to match m with m, and the temperature may be tracked and controlled so that the temperature is lower than the target temperature Tm by 1 ° C., for example. Therefore, in the present invention, the spindle temperature is the target temperature T
It is controlled to tune to m. As described above, in the present embodiment, it is desired to control the spindle temperature so as to be synchronized with the target temperature Tm, but since the spindle is constantly rotating and the temperature varies depending on the part, for convenience, the return (cooling) liquid temperature Tr is set. Is considered to indicate the spindle temperature. Of course, the temperature of the spindle housing near the tip of the spindle may be adopted as the spindle temperature. In this embodiment, the controller 11 controls the solenoid on-off valves Sol.1 and Sol.2 so that the average temperature of the cooling liquid 3 supplied to the spindle device 15 such that the return liquid temperature Tr = the target temperature Tm is obtained. ON / OFF is controlled by the time ratio table.

The table shown in FIG. 2 is a solenoid on-off valve Sol.
1 shows an example of the ON / OFF time ratio of Sol. 2, and the table is registered in the storage device of the controller 6 in advance. In the table, i is a ranking assigned to each registered time ratio. Then, the relationship of t ₁ : t ₂ = a: b is introduced. Here, a and b are ON / OFF time ratio coefficients of solenoid on-off valve Sol.1 and solenoid on-off valve Sol.2, where a + b
= 10, t ₁ is the time when the solenoid on-off valve Sol.1 is OFF (open), while the solenoid on-off valve Sol.2 is OFF (closed), and t ₂ is
Solenoid on-off valve Sol.1 is ON (closed), and solenoid on-off valve So
It is the time when l.2 is ON (open).

For example, when the controller 11 commands the order i = 1 of the table, the output is that the solenoid opening / closing valve Sol.1 is fully closed and the solenoid opening / closing valve Sol.2 is fully opened in the time zone of a + b = 10. Constant discharge pump 23, that is, spindle device 15
Is supplied with only the warm cooling liquid from the second tank 17. Therefore, the cooling action of the spindle device 15 is relaxed. When the order i = 3 is instructed, the solenoid on-off valve Sol.1 opens for 2 unit hours during the time period a + b = 10, during which the solenoid on-off valve Sol.2 closes, and then the solenoid on-off valve Sol. .2 is opened for 8 unit hours, during which the solenoid on-off valve Sol.1 is closed, so that the constant discharge pump 23 receives the coolant 3 from the first tank 1 within a + b time. 2 units, then the cooling liquid from the second tank 7 is supplied at a ratio of 8 units. Therefore, the cooling action of the spindle device 15 is slightly stronger than when the rank i = 1.

Since the a + b time zone is relatively short in itself, and the temperature capacity of the spindle device is extremely large, the sampling time t ₃ is formed by using some of the time zones as a unit, and the sampling time t ₃ is formed. The liquid temperature of the cooling liquid sequentially supplied into the spindle device 15 during the time t ₃ is the same as that in the first tank 1
The temperature of the cooling liquid 3 from the second tank 13 and the temperature of the slightly warm cooling liquid from the second tank 13 are averaged, and can be regarded as a cooling liquid having a predetermined temperature as a whole. Fig. 3 shows the solenoid valve So
It shows an example of a control signal for turning on and off l.1 and Sol.2, and the symbols attached to the figures have already been described.

The operation of the spindle temperature control method and apparatus described above will be outlined below. Now, assuming that the solenoid opening / closing valves Sol.1 and Sol.2 are controlled to be turned on and off in the i order shown in FIG. 2, the return liquid temperature Tr output from the second temperature detector 13 is Third temperature detector attached to 25
If the temperature falls below the target temperature Tm, which is the output of 27 (too cold), the controller 11 calculates from the respective input values and outputs (i-1) to the solenoid opening / closing valves Sol.1 and Sol.2. )
Command the timetable of rankings. Then, as shown in the table of FIG. 2, each solenoid opening / closing valve Sol.1 is set so that the opening time of the solenoid opening / closing valve Sol.1 is further reduced and the opening time of the solenoid opening / closing valve Sol.2 is increased by a ratio within a + b time. , Sol.2 ON / OFF time is controlled.

That is, as shown in FIG. 3, during the next sampling time t ₃ , the ratio of the cooling liquid 3 supplied from the first tank 1 is generally smaller than that in the second tank 13, The warmer cooling liquid is supplied to the spindle device 15, and the supercooling of the spindle against the target temperature Tm is gradually corrected. After sampling time t _3, the controller 6 again detects the value of Tm -Tr, selects the order of the time table.

That is, two cold and hot homogeneous liquids are prepared in separate tanks in advance, and the controller 11 is operated at regular intervals.
Detects the value of Tm-Tr and, accordingly, each time,
ON / OF of solenoid on / off valves Sol.1 and Sol.2 communicating with each tank
By controlling the F time width and controlling the volume ratio of the supplied cold / hot liquid within a unit time, the overall supplied liquid temperature is controlled as desired. However, at that time,
The cold / hot liquids in the first and second tanks are not mixed at the combiner 21, but both liquids are sequentially passed through the combiner 21 to form cold, hot, cold, hot and hot layers according to the instruction of the time ratio table. And are alternately delivered to the fixed amount discharge pump 23 side.

However, if the length of the sampling time t ₃ is sufficiently shorter than the temperature capacity of the spindle device 8, it is substantially the same as the case of the prior art in which the cold / hot liquid is mixed at a predetermined ratio. Produce an effect. In the present embodiment, basically, a simple control method of ON / OFF control of the valve is adopted, so that despite the inexpensive control device / method, the temperature displacement of the spindle is small, and the fluctuation range is highly accurate. Control can be realized.

[0026]

The method and apparatus for controlling the spindle temperature according to the present invention are
Since the structure and operation as described above are provided, (1) complicated and expensive equipment such as a servo valve is not required, and it is more economical than control characteristics. (2) The spindle temperature can be quickly brought to the target temperature Tm by a simple control method by simply changing the opening / closing time ratio of the on / off valve for the cold and hot two liquids, and the control method is simple.

(3) Since it is not an ON / OFF control of the cooler that directly cools the cooling liquid supplied to the spindle, it has good responsiveness to changes in the spindle temperature and reduces the thermal displacement and fluctuation range of the spindle. be able to. And so on, a special operation and effect which cannot be expected by the conventionally known method and apparatus for controlling the spindle temperature of a machine tool are exhibited.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a method and apparatus for controlling a spindle temperature of a machine tool of the present invention.

FIG. 2 is a solenoid on-off valve Sol.1, which is an embodiment of the device of the present invention.
An example of the ON / OFF time ratio table for Sol.2 is shown below.

FIG. 3 is a solenoid on-off valve Sol.1, according to an embodiment of the method of the present invention.
It is an example of a control signal for turning on and off Sol.2.

[Explanation of symbols]

 1 1st tank 17 2nd liquid temperature detector 3 Cooling liquid 21 Combiner 5 Pump 23 Constant discharge pump 7 Cooler 25 Bed 9 1st liquid temperature detector 27 3rd temperature detector 11 Controller 13 2nd tank 15 Spindle device

Claims (3)

[Claims] 1. A spindle temperature control method for a machine tool, wherein a spindle fluid device of a machine tool is externally supplied with a predetermined flow rate of a cooling liquid so that the spindle temperature is synchronized with a target temperature. The cooling liquid cooled in the first tank is stored in the first tank, the cooling liquid supplied to the spindle device and warmed is collected and stored in the second tank, and the cooling liquid in the first tank and the cooling liquid in the second tank are stored. Coolant is supplied alternately to the spindle device, and the supply time of the coolant of the first tank and the cooling of the second tank within a predetermined unit time are adjusted so that the temperature of the spindle is synchronized with the target temperature. A spindle temperature control method for a machine tool, characterized by controlling a ratio with a liquid supply time. 2. A spindle temperature control device for a machine tool, wherein a spindle fluid of a machine tool is externally supplied with a predetermined flow rate of cooling liquid to control the spindle temperature so as to synchronize with the target temperature. A first tank for storing the cooled cooling liquid, a second tank for collecting and storing the cooled cooling liquid supplied to the main spindle device, cooling the cooling liquid for the first tank and the cooling for the second tank Cooling liquid supply means for alternately supplying liquid and liquid to the main spindle device, and a supply time of the cooling liquid of the first tank and the second liquid within a predetermined unit time so that the temperature of the main shaft is synchronized with the target temperature. A spindle temperature control device for a machine tool, comprising: a control unit that controls a ratio with a supply time of the coolant of the tank. 3. The cooling liquid supply means merges the pipeline from the first tank and the pipeline from the second tank into a single pipeline, and pump means is provided in the single pipeline. And a first on-off valve between the first tank and the merging conduit, and a second on-off valve between the second tank and the merging conduit. When the first opening / closing valve is open, the second opening / closing valve is closed, and the first opening / closing valve is closed.
The second opening / closing valve is configured to be opened when the opening / closing valve is closed, and the control means controls the first and second opening / closing within a predetermined unit time so that the temperature of the spindle is synchronized with the target temperature. 3. A structure for controlling the opening / closing time ratio of the valve.
A spindle temperature control device for a machine tool according to.