JP2001059521A - Method for controlling lubricating fluid temperature of hydraulic bearing and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain temperature of a hydraulic bearing and a spindle within an exceedingly small allowable range regardless of a change in the number of revolution of the spindle. SOLUTION: Lubrication fluid in a tank 13 is cooled to a desired temperature T0 lower than a reference temperature T1, and temperature T2 of the lubricating fluid at the time when discharged from hydraulic bearings 9, 10 and before returned to the tank 13 is detected by using discharging temperature sensor 22. Temperature of the lubricating fluid supplied to the hydraulic bearings 9, 10 is adjusted by ON/OFF controlling a heater 20 such that the detected temperature T2 becomes equal to the reference temperature T1. Temperature change of the lubricating fluid around the hydraulic bearings 9, 10 and the spindle 1 is thereby suppressed to minimum to suppress dimensional change of the spindle 1 caused by thermal change, and processing precision of a work can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling a lubricating fluid temperature of a hydraulic bearing for controlling the temperature of a lubricating fluid supplied to a hydraulic bearing which rotatably supports a spindle in a machine tool or the like.

[0002]

2. Description of the Related Art Conventionally, in a machine tool for processing a workpiece by mounting a tool on a spindle and rotating the spindle together with the tool, a configuration in which the spindle is supported by a hydraulic bearing is known. This hydraulic bearing is intended to supply lubricating fluid to a gap formed between the spindle and the spindle, and to smoothly rotate the spindle by pivotally supporting the spindle without contacting the surrounding metal members. Lubricating oil is often used as a lubricating fluid, but a fluid in which a gas such as air and an oil mist are mixed may be used. Such a lubricating fluid is supplied from a tank to a hydraulic bearing with a desired pressure by a pump or the like, and is discharged from the hydraulic bearing and returned to the tank.

On the other hand, the temperature of the rotating spindle and the lubricating fluid rises due to friction as the rotation speed of the spindle increases, which affects the processing accuracy of the work. Since the spindle is long in the axial direction, the change in the length in the axial direction is greater than the change in the outer diameter. As a result, the position of the tool that comes into contact with the work is changed, and the dimensional accuracy of the work is greatly affected. For these reasons, proposals have been made for measures against temperature rise.

[0004] Hereinafter, a conventional technique for preventing a temperature rise will be described. In the prior art described in Japanese Patent Publication No. 8-345, an inner jacket and an outer jacket are provided in a double manner on a headstock in which a spindle bearing is fitted, and the heat of the entire mechanical structure is determined from machining conditions such as the spindle rotation speed. Calculate changes in deformation and introduce supercooled cooling oil into the inner jacket by operations such as forced cooling to suppress heat generation in the main shaft bearings, and introduce cooling oil at a temperature approximately equal to the mechanical structure temperature to the outer jacket. It describes that a part other than the main shaft bearing is prevented from being supercooled, thereby suppressing thermal deformation of the machine tool.

In Japanese Patent Application Laid-Open No. 60-80544, a lubricating oil path for supplying lubricating oil around the spindle is provided, and a circulation path for supplying cooling fluid is provided adjacent to the lubricating oil path. It describes that the temperature of the spindle is made constant by controlling the supply amount of the cooling liquid according to the rotation speed.

[0006] Further, in order to keep the temperature of the bearing oil supplied to the hydraulic bearing constant, the temperature of the bearing oil in the liquid tank is first set to a target temperature. By controlling the temperature to a lower temperature, the bearing oil supplied from the liquid tank is heated by the heater, and at this time, the output of the heater is adjusted based on the temperature detected at the outlet of the heater to supply the oil to the hydraulic bearing. At the previous time, the temperature of the bearing oil is controlled to a target value, and further, the bearing oil is guided to the damping tank to absorb a steep temperature change and then to be supplied to the hydraulic bearing.

[0007]

The internal temperature of the hydraulic bearing changes immediately in proportion to the rotational speed of the spindle, and the axial length of the spindle also changes in a short time. Further, the width of change in the internal temperature of the hydraulic bearing differs depending on the variable rotational speed of the spindle and the outer diameter of the spindle in the bearing portion.

In the prior art described in Japanese Patent Publication No. 8-345, a method of cooling the outside of the spindle is used.
It is not possible to control up to the bearing internal temperature, which changes according to the rotation speed. Therefore, displacement in the spindle axis direction cannot be precisely suppressed.

In the prior art described in Japanese Patent Application Laid-Open No. Sho 60-80544, the ambient temperature of the spindle is controlled in accordance with the rotation speed of the spindle by using a cooling liquid. Responsiveness is poor due to indirect control. Therefore, when the rotation speed of the spindle is frequently changed, it is not possible to cope with the spindle displacement that changes in a short time, and the change may become unstable and adversely affect.

In the prior art described in Japanese Patent Application Laid-Open No. 5-99227, the temperature of the bearing oil before supply to the hydraulic bearing can be kept constant. However, this does not make the temperature change of the hydrostatic bearing constant when the rotational speed of the spindle supported by the hydrostatic bearing is changed according to the processing conditions.

An object of the present invention is to maintain the temperatures of the hydraulic bearing and the spindle within an excessively small allowable range irrespective of a change in the number of revolutions of the spindle during machining of the workpiece.

[0012]

According to a first aspect of the present invention, a lubricating fluid temperature control method for a hydraulic bearing supplies a lubricating fluid contained in a tank to a hydraulic bearing which supports a spindle and is discharged from the hydraulic bearing. in the lubricating fluid temperature control method of a hydraulic bearing for returning said lubricating fluid to the tank, maintaining the desired temperature T ₀ lower than the reference temperature T ₁ of which is set the lubricating fluid in the tank is discharged from the hydraulic bearing The temperature T of the lubricating fluid before being returned to the tank
₂ under the condition that the temperature T ₂ > the desired temperature T ₀ , the lubrication supplied from the tank to the hydraulic bearing such that the detected temperature T ₂ is equal to the reference temperature T _1. Adjust the temperature of the fluid.

[0013] Thus, the temperature of the lubricating fluid in the hydraulic bearing is varied by the rotation speed of the spindle, but in accordance with the temperature of the lubricating fluid that changes, temperature T ₂ is the reference temperature T of the lubricant fluid discharged from the hydraulic bearing By adjusting the temperature of the lubricating fluid supplied from the tank to the hydraulic bearing so as to be equal to ₁ , it is possible to minimize the temperature change of the lubricating fluid around the hydraulic bearing and the spindle.

According to a second aspect of the present invention, there is provided a method for controlling a lubricating fluid temperature of a hydraulic bearing according to the first aspect, wherein the spindle is rotated at a predetermined rotational speed for a predetermined period of time immediately after being discharged from the hydraulic bearing. to set the temperature T ₂ of said detected lubricating fluid as the reference temperature T _1.

Therefore, the reference temperature T ₁ can be automatically set by rotating the spindle at the time of starting.

According to a third aspect of the present invention, there is provided the lubricating fluid temperature control device for a hydraulic bearing, wherein the lubricating fluid contained in the tank is supplied to a hydraulic bearing which supports a spindle, and the lubricating fluid discharged from the hydraulic bearing is supplied to the tank. In a lubricating fluid temperature control device for a hydraulic bearing to be recirculated, a reference temperature setting means for setting a reference temperature T ₁ and a lubricating fluid temperature setting in a tank for setting a set temperature of the lubricating fluid in the tank to a desired temperature T _0. Means, an in-tank temperature detecting means for detecting a temperature T of the lubricating fluid in the tank, and a discharge temperature detection for detecting a temperature T _{2 of the} lubricating fluid before being discharged from the hydraulic bearing and returned to the tank. Means for cooling the lubricating fluid in the tank to a desired temperature T ₀ lower than a reference temperature T ₁ in accordance with the temperature T detected by the tank temperature detecting means. Comprising means and, a lubricant temperature adjusting means for adjusting the temperature of the lubricating fluid and the temperature T ₂ and the reference temperature T ₁ is supplied to the hydraulic bearing from the tank to become equal.

Therefore, the lubricating fluid in the tank is cooled to a desired temperature T ₀ by the cooling means in accordance with the temperature T detected by the tank temperature detecting means, and is supplied to the hydraulic bearing by the supply means. temperature is adjusted by the lubricant temperature adjusting means so that the temperature T ₂ of the lubricating fluid immediately after being discharged from the bearing is maintained constant. The lubricating fluid discharged from the hydraulic bearing has a temperature T
_{After 2} is detected, the temperature is returned to the tank and cooled in the tank to reach the desired temperature T ₀ . In the circulation cycle of the lubricating fluid, the temperature of the lubricating fluid supplied to the hydraulic bearings, the temperature T ₂ of the lubricating fluid as it is discharged from the hydraulic bearing is always adjusted by the lubricating fluid regulating means to be constant.
Therefore, the temperature of the lubricating fluid around the hydraulic bearing and the spindle changes according to the rotation speed of the spindle, and the temperature of the lubricating fluid discharged from the hydraulic bearing is changed to the reference temperature T ₁ according to the temperature of the lubricating fluid changing as described above. Temperature T ₂ equal to
By adjusting the temperature supplied to the hydraulic bearing so as to maintain the condition, the temperature change of the lubricating fluid around the hydraulic bearing and the spindle is suppressed to an excessively small value.

According to a fourth aspect of the present invention, in the lubricating fluid temperature control device for a hydraulic bearing according to the third aspect of the present invention, the reference temperature setting means is based on an input value from a manual input section for manually inputting a set value. The reference temperature T ₁ is set, and the tank lubricating fluid temperature setting means sets the desired temperature T ₀ based on an input value from a manual input unit for manually inputting a set value.

Therefore, the reference temperature T ₁ and the desired temperature T ₀ of the lubricating fluid in the tank can be set to be changeable.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a spindle. The spindle 1 has a tapered portion 2 and a flange 3 for mounting a grindstone (not shown) near the tip. A plurality of sleeves 5, 6, 7 are fixedly fitted on the inner surface of the cylindrical shaft 4 surrounding the spindle 1. A slight gap is formed between the sleeves 5, 6, 7 and the spindle 1, and the gap between the sleeves 5, 7 and the spindle 1 is filled with lubricating oil as a lubricating fluid by applying a predetermined pressure. To form a hydrostatic bearing (radial hydrostatic bearing) 9 as a hydraulic bearing. Similarly, by filling a gap between the end surfaces of the sleeves 5 and 6 and the side surface of the flange 3 with lubricating oil, a hydrostatic bearing as a hydraulic bearing is formed. (Thrust hydrostatic bearing) 10 is formed. The cylindrical shaft 4 has a supply port 11 for supplying lubricating oil to the hydrostatic bearings 9 and 10, and a discharge port 12 for discharging lubricating oil warmed by rotation of the spindle 1 from the hydrostatic bearings 9 and 10. Are formed. The spindle 1 is driven by a motor (not shown). In this example, the spindle 1 of the grinding machine is described. However, the structure of supporting the spindle 1 is also applicable to the case of supporting the spindle of another machine tool.

As shown in FIG. 1, a tank 13 containing lubricating oil is provided with a stirrer 14 for stirring lubricating oil and a tank temperature sensor 15 whose output changes in accordance with the temperature of the lubricating oil. ing. A cooling device 16 for cooling the lubricating oil in the tank 13 is provided above the tank 13. The cooling device 16 includes a pipe 16a for circulating the cooled lubricating oil in the tank 13.

A pump 18 for supplying lubricating oil, a valve 19 and a heater 20 are sequentially connected to a supply pipe 17 connecting the tank 13 and a supply port 11 formed in the cylindrical shaft 4. I have. Further, a return temperature sensor 21 whose output changes in accordance with the temperature of the lubricating oil immediately after being discharged from the discharge port 12 is provided in a return line 21 connecting the discharge port 12 formed in the cylindrical shaft 4 and the tank 13. 22 are provided.

Here, a microcomputer not shown (hereinafter referred to as a microcomputer) is provided, and the microcomputer determines the output of the tank temperature sensor 15 to detect the temperature T of the lubricating oil in the tank 13. A temperature detecting means is realized. Moreover, by determining the output of the exhaust temperature sensor 22 in the microcomputer, the discharge temperature detection means for detecting a temperature T ₂ of the lubricating oil is achieved before being recirculated to the to the tank 13 discharged from the hydrostatic bearings 9, 10 .

The heater 20 has an oil temperature controller 23
Is connected. The oil temperature control device 23 includes a manual input unit (not shown) as a reference temperature setting unit for setting the reference temperature T ₁ , and turns on / off the heater 20 according to the output of the discharge temperature sensor 22. That is, the lubricating fluid temperature adjusting means is realized by the heater 20 and the oil temperature control device 23. The lubricating fluid adjusting means adjusts the temperature of the lubricating oil supplied to the hydrostatic bearings 9 and 10 by the pump 18 to T2 where the temperature of the lubricating oil discharged from the hydrostatic bearings 9 and 10 is equal to the reference temperature T1. Adjust heating.

In this embodiment, the reference temperature T ₁ is substantially equal to the room temperature at which the machine tool including the spindle is installed.

The cooling device 16 lowers the lubricating oil in the tank 13 below the reference temperature T ₁ according to the lubricating oil temperature T in the tank 13 detected based on the output of the in-tank temperature sensor 15. Cool to temperature. Specifically, the reference temperature T ₁
A manual input unit (not shown) is provided as an in-tank lubricating fluid temperature setting unit for setting a lower desired temperature T ₀ , and drive / stop control is performed so that the temperature T of the lubricating oil in the tank 13 becomes T _0. I do. In this case, the desired temperature T ₀ to be set is about 10 ° C. lower than the reference temperature T ₁ , for example, when the room temperature is 25 ° C.
In the case of ° C, about 15 ° C is desirable.

In such a configuration, the grinding machine is started to rotate the spindle 1 and the cooling device 16
And after starting the oil temperature control device 23 and driving the pump 18, the cooling process of the cooling device 16 and the oil temperature control device 23
Is performed.

First, the cooling process will be described with reference to FIG. It is assumed that the desired temperature T ₀ of the lubricating oil in the tank 13 is set in advance. If the desired temperature (cooling temperature) T ₀ is set (Y in S1), the temperature T of the lubricating oil in the tank 13 is determined based on the output of the tank temperature sensor 15.
Is detected (S2). Subsequently, the set desired temperature T ₀ is compared with the detected temperature T (S3). If T ₀ ≧ T (Y in S3), the cooling device 16 is stopped (S4), and T _{0 is set.}
≧ T Otherwise (S3 of N), and drives the cooling unit 16 (S5), by repeating the processing of steps S2~ step S5, lower than the reference temperature T ₁ of the temperature T of the lubricant oil in the tank 13 T Cool to ₀ .

The lubricating oil thus cooled is supplied to the pump 18
, Are supplied to the hydrostatic bearings 9 and 10, but are heated by a heater 20 driven by an oil temperature control device 23 on the way. The lubricating oil supplied to the hydrostatic bearings 9 and 10 is discharged from the discharge port 12 and returned to the tank 13 through the discharge temperature sensor 22. At this time, the discharge temperature sensor 22
Temperature T ₂ of the lubricating oil around the hydrostatic bearings 9 and 10 based on the output of
Is detected.

Next, the temperature control process will be described with reference to FIG. Reference temperatures T ₁ is assumed to be preset. If the reference temperature T ₁ is set (S11
Of Y), the detected temperature T ₂ of the discharge side of the lubricating oil of the hydrostatic bearing 9, 10 as described above (S12). Then, comparing the temperature T ₂ detected with the reference temperature T ₁ (S13). T ₂ ≧
If T1 (S13 of Y), the OFF the heater 20 (S14), if not T ₂ ≧ T ₁ (S13 of N), it turns ON the heater 20 (S15), the processing of step S12~ step S15 By repeating this, the temperature of the lubricating oil before being supplied to the hydrostatic bearings 9 and 10 is adjusted so that the reference temperature T ₁ and the temperature T ₂ of the lubricating oil around the hydrostatic bearings 9 and 10 become equal.

Here, in FIG. 2, steps S1 to S5 are cooling means for cooling the lubricating oil in the tank 13 to a desired temperature T ₀ lower than the reference temperature T ₁ according to the temperature T detected in the tank 13. Is equivalent to Step S
Reference numeral 2 corresponds to an in-tank temperature detecting means for detecting the temperature T of the lubricating oil in the tank 13.

[0032] In FIG. 3, step S12 corresponds to the discharge temperature detection means for detecting a temperature T ₂ of the lubricating oil before being recirculated to the to the tank 13 discharged from the hydrostatic bearings 9,10. Further, step S11~ step S15, corresponds to the lubricating fluid temperature adjusting means for adjusting the temperature of the lubricating oil flowing between the pump 18 and the hydrostatic bearing 9, 10 until the temperature T ₂ and the reference temperature T ₁ of equal I do.

As described above, the reference temperature T ₁ (for example, room temperature of 25 ° C.) is set for the lubricating oil stored in the tank 13.
The lubricating oil is cooled to a lower temperature T ₀ (for example, 15 ° C.), the lubricating oil temperature T ₂ before being discharged from the hydrostatic bearings 9 and 10 and returned to the tank 13 is detected, and the detected temperature T ₂ and the reference temperature are detected. The temperature of the lubricating oil discharged from the hydrostatic bearings 9, 10 is maintained at T2 between the tank 13 and the hydrostatic bearings 9, 10 so that T ₁ (25 ° C.) becomes equal to the reference T1. By adjusting the temperature of the lubricating oil supplied to the static pressure bearings 9 and 10 by ON / OFF of the heater 20, even if the rotation speed of the spindle 1 changes, the static pressure bearings 9 and 10 are changed.
Temperature changes of the lubricating oil around the spindle 10 and the spindle 1 are suppressed to be too small.

The effect of adjusting the temperature of the lubricating oil supplied to the hydrostatic bearings 9 and 10 according to the temperature T _{2 of the} lubricating oil discharged from the hydrostatic bearings 9 and 10 will be shown by experiments. FIG. 4 shows the experimental results. In this experiment, the spindle 1 was set at 2400 rpm (30 minutes) and 800 rpm.
(15 minutes), the rotation speed is repeatedly changed, and rotation is performed. At that time, a change in the length of the spindle 1 due to a change in heat and a detected temperature T _{2 of the} lubricating oil discharged from the hydrostatic bearings 9 and 10 are measured. I do.

As a result, the rotational speed is increased from 2400 rpm to 8
The temperature T ₂ of the detected lubricating oil decreases when lowered to rpm, temperature T ₂ is increased by warming the lubricant oil in the heater 20 by the difference T ₁ and T _2, the state of this increase T recognized by the _second temperature detection, T ₂ is lowered again by the heater 20 to OFF. As described above, the temperature T ₂ around the hydrostatic bearings 9 and 10 and the spindle 1 changes as the rotation speed of the spindle 1 changes, but the heater 20 is immediately turned on and off in accordance with the temperature change.
The temperature around the hydrostatic bearings 9 and 10 and the spindle 1 is 25 ° C
It can be maintained in a small range of ± 1 ° C. Thus, the change in the length of the spindle 1 can be maintained in an extremely small range of about 1 μm. FIG. 4 shows that the reference temperature T ₁ is 25.
It is an experimental result at the time of setting to ° C.

[0036] In contrast, without detecting the temperature T ₂ of the lubricating oil discharged from the hydrostatic bearings 9 and 10, just in the case of a constant temperature of the lubricating oil before being fed to the hydrostatic bearings 9, 10 The experimental results are shown in FIG. The number of rotations and the rotation time of the spindle 1 are the same as those in FIG. In this experiment, it was confirmed that the change in the temperature T ₂ of the lubricating oil discharged from the hydrostatic bearings 9 and 10 was as large as 3 to 4 ° C., and the length of the spindle 1 was as large as about 3 μm.

The rotation speed of the spindle 1 in the above experiment was 2400 rpm for grinding the work and 800 rpm for dressing the grindstone mounted on the spindle 1. In the conventional case (in the case of FIG. 5),
Immediately after the transition from dressing to work grinding, the spindle 1 expands by 3 μm or more due to an increase in heat, so it is difficult to keep the dimensional accuracy of the work within an allowable value. On the other hand, in the present embodiment (in the case of FIG. 4), since the change in the length of the spindle 1 is about 1 μm, the period in which the spindle 1 expands due to an increase in heat immediately after shifting from dressing to work grinding. Even if it does, there is no problem on the dimensional accuracy of the work.

In this example, the number of revolutions of the spindle 1 is changed between the work grinding and the dressing. However, the number of revolutions of the spindle 1 may be changed depending on the grinding accuracy of the work, the material of the work and the like.

[0039] The reference temperature setting means in the present embodiment, since includes a manual input unit for inputting manually a setting value of T _1, can be changeably set the reference temperature T _1.

[0040] Alternatively, the reference temperature setting means may set the temperature T ₂ of the lubricant oil detected when rotating a predetermined time of the spindle 1 at a predetermined rotational speed as the reference temperature T _1. For example, considering the case of FIG. 4, in the case of a grinding machine used as a single-purpose machine that rotates the spindle 1 only at 2400 rpm, 2400 rpm is used for warm-up operation.
Rotate certain time the spindle 1 at speed, by the temperature T ₂ detected at this time as a reference temperature T _1,
A reference temperature T ₁ of can be automatically set.

Although the hydraulic bearings in the present embodiment have been described by taking the hydrostatic bearings 9 and 10 as an example, it goes without saying that the present invention can also be used for dynamic pressure bearings.

[0042]

Effects of the Invention According to the invention of claim 1 and claim 3, wherein, cooled to a desired temperature T ₀ lower than the reference temperature T ₁ of which is set the lubricating fluid in the tank, circulated to the tank is discharged from the hydraulic bearing The temperature T ₂ of the lubricating fluid before being detected is detected, and the temperature of the lubricating fluid supplied to the hydraulic bearing is adjusted so that the detected temperature T ₂ maintains a substantially constant temperature. The temperature change of the lubricating fluid around the spindle can be suppressed to an excessively small value. Thereby, the dimensional change of the spindle due to the heat change can be suppressed, and the processing accuracy of the work can be increased.

According to the second aspect of the present invention, the reference temperature setting means converts the lubricating fluid temperature T ₂ detected when the spindle is rotated at a predetermined rotation speed for a predetermined time to the reference temperature T _1.
By setting as the reference temperature T ₁ of it can be automatically set.

According to the fourth aspect of the present invention, the reference temperature T ₁ and the desired temperature T ₀ of the lubricating fluid in the tank are set based on the input value from the manual input section for manually inputting the set value. The reference temperature T ₁ and the desired temperature T ₀ can be set to be changeable.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is an explanatory view showing a circulation path of lubricating oil with a hydraulic bearing in cross section.

FIG. 2 is a flowchart illustrating a cooling process of a cooling device.

FIG. 3 is a flowchart showing a temperature control process of an oil temperature control device.

FIG. 4 is a graph showing a change in lubricating oil temperature and a change in spindle length with respect to a change in spindle rotation speed.

FIG. 5 is a graph showing a change in lubricating oil temperature and a change in spindle length with respect to a change in the number of revolutions of the spindle in the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle 9,10 Hydraulic bearing 13 Tank S1-S5 Cooling means S2 Tank temperature detecting means S11-S15 Lubricating fluid temperature adjusting means S12 Discharge temperature detecting means

Claims (4)

[Claims] 1. A lubricating fluid temperature control method for a hydraulic bearing, wherein a lubricating fluid contained in a tank is supplied to a hydraulic bearing that supports a spindle, and the lubricating fluid discharged from the hydraulic bearing is returned to the tank. A reference temperature T ₁ at which the lubricating fluid in the tank is set.
Maintaining the lower desired temperature T ₀ , detecting the temperature T _{2 of the} lubricating fluid before it is discharged from the hydraulic bearing and returned to the tank, and is detected on condition that the temperature T ₂ > the desired temperature T _0. has been the temperature T ₂ and the reference temperature T ₁ of the lubricating fluid temperature control method of a hydraulic bearing, characterized by adjusting the temperature of the lubricating fluid supplied to the hydraulic bearing from the tank to be equal. Wherein setting the temperature T ₂ of said immediately after being discharged from the hydraulic bearing detected the lubricating fluid when rotating a predetermined time said spindle at a predetermined rotational speed as the reference temperature T ₁ of 2. The method for controlling lubricating fluid temperature of a hydraulic bearing according to claim 1, wherein: 3. A lubricating fluid temperature control device for a hydraulic bearing, wherein a lubricating fluid contained in a tank is supplied to a hydraulic bearing that supports a spindle, and the lubricating fluid discharged from the hydraulic bearing is returned to the tank. A reference temperature setting means for setting a reference temperature T _1; and a set temperature of the lubricating fluid in the tank to a desired temperature T _0.
A tank lubricating fluid temperature setting means for setting the temperature of the lubricating fluid in the tank; a tank temperature detecting means for detecting a temperature T of the lubricating fluid in the tank; and a lubricating fluid discharged from the hydraulic bearing and returned to the tank. a discharge temperature detection means for detecting a temperature T _2, the temperature T detected by the tank temperature detecting means
The lubricating fluid in the tank according to the reference temperature T
Lubricating fluid temperature adjusting a cooling means for cooling the desired temperature T ₀ lower than _1, the temperature of the lubricating fluid and the temperature T ₂ and the reference temperature T ₁ is supplied to the hydraulic bearing from said tank to equal Adjusting means for controlling the lubricating fluid temperature of the hydraulic bearing. 4. The reference temperature setting means sets the reference temperature T ₁ based on an input value from a manual input section for manually inputting a set value, and the tank lubricating fluid temperature setting means sets the reference value. 3. hydraulic bearing lubricating fluid temperature control device, wherein the setting the desired temperature T ₀ on the basis of the input values from the manual input unit for inputting manually a.