JPH01171006A - Main shaft built-in type motor cooling system - Google Patents

Abstract

PURPOSE:To suppress the temperature rise, to improve the working accuracy and to prevent the lubricating defect by detecting the temperature of the prescribed place of a motor, obtaining the deviation of a detecting value and a target temperature command value, adjusting the temperature of a cooling medium and circulating the temperature adjusted cooling medium to the motor. CONSTITUTION:The title system is provided with a subtracter 10B to obtain a deviation SF of a detecting value SE from a temperature detector 9B in a stator 5 and a detecting value SA from a temperature detector 9A in a cooling water tank 6 and a limiter 13 to compare the deviation SF from the subtracter 10B and an upper limit value SG set beforehand, to output the deviation SF as it is when the deviation SF is smaller, and to output the upper limit value SG when the deviation SF is larger. The system is provided with a subtracter 10C to obtain a deviation SI of a value SH from the limiter 13 and the deviation SF from the subtracter 10B, a subtracter 10D to obtain the deviation SI from the subtracter 10C and deviation SJ of the detecting value SE from the temperature detector 9B and output it to a subtracter 10A and an insulating material 14 sandwiched between a stator 4 and a main shaft stand 3. Thus, the temperature rise is suppressed, the dimension accuracy is improved and the lubricating defect is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for cooling a motor incorporated in a main shaft of a machine tool or the like.

(Prior Art) In order to improve productivity and improve the accuracy and roughness of cutting surfaces when machining with machine tools such as lathes and machining centers, it is necessary to increase the rotation speed of the main spindle of the machine tool. When rotating the spindle at high speed, using a belt, gear, or coupling to rotate it tends to generate vibrations and it is difficult to ensure rotational accuracy of the spindle, so the motor rotor is fixed to the spindle body. However, it is common to rotate the machine using a so-called spindle built-in motor in which the stator of the motor is fixed to the headstock (machine main body). However, due to the structure of this main shaft built-in motor, heat generated on the rotor side of the motor is easily transmitted to the main shaft body, and heat generated on the motor stator side is easily transmitted to the head stock. Then, the temperature of the main spindle increases significantly, causing thermal expansion, leading to problems such as deterioration of machining accuracy and poor lubrication of the main spindle bearing during high-speed rotation, causing damage to the bearing. Therefore, a spindle built-in motor is generally used while being cooled.

Figure TS2 is a block diagram and a cross-sectional structural diagram showing an example of a cooling device and a main shaft built-in motor that realize a conventional cooling system for a main shaft built-in motor. , a stator 5 fixed to the inner periphery of the headstock 3 via a sleeve 4, and cooling water 6 stored in a cooling water tank 6 in a cooling water channel 4a provided inside the sleeve 4.
It has a pump 7A and piping 8A that circulate the water. Furthermore, the cooling water 6a is disposed inside the cooling water tank 6, and
temperature detector 9A that detects the water temperature of
Deviation SC between detected value SA and target temperature command value SR from 8.
a subtracter 10A for calculating the value, an amplifier 11 for amplifying the deviation SC from the subtracter 10A, a pump 7B and piping 8 for circulating the cooling water 6a stored in the cooling water tank 6.
B, and a temperature regulator 12 that is disposed in the middle of this pipe 8B and adjusts the temperature of the circulating cooling water 6a based on the deviation SD from the amplifier 11.

(Problems to be Solved by the Invention) According to the cooling method using the cooling device described above, the heat generated by the stator 5 and the rotor 2 can be cooled down by the cooling water 6a at a constant temperature through the sleeve 4. However, since the iron core material forming the stator 5 generally has a high thermal resistance, the temperature rise at its inner diameter portion increases, and in the end, the temperature rise at the main shaft cannot be suppressed to a low level.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a cooling method that can suppress the temperature rise of a main shaft built-in motor to a low level.

(Means for Solving the Problems) The present invention relates to a method for cooling a motor incorporated in a main spindle of a machine tool, etc., and the above object of the present invention is to provide cooling medium ( When cooling the motor by circulating water (for example, water), the temperature at a predetermined location of the motor is detected, the deviation between this detected value and a target temperature command value is determined, and the temperature of the cooling medium is adjusted. This is accomplished by allowing a regulated cooling medium to circulate through the motor.

(Function) The cooling method for the spindle built-in motor of the present invention measures the temperature of the part that generates the most heat and adjusts the temperature of the cooling medium such as cooling water, so it can perform appropriate cooling. It is something.

(Example) FIG. 1 is a block diagram and a cross-sectional structural diagram showing an example of a cooling device and a main shaft built-in motor that realize the cooling method of the main shaft built-in motor of the present invention, corresponding to FIG. , the same constituent parts are given the same reference numerals and the description thereof will be omitted. This cooling device is provided with a temperature detector 9B that is embedded in the inner diameter portion of the stator 5 and detects the temperature of the inner diameter portion of the stator 5. The detected value SE from this temperature detector 9B is converted to the conventional temperature detector 9.
Since the temperature of the cooling water 6a is automatically adjusted using the detected value S instead of the detected value S from A, the temperature of the inner diameter portion of the stator, which generates a large amount of heat, can be lowered to the target temperature and kept constant. In addition, when the temperature of the cooling water 6a is automatically adjusted, the temperature of the cooling water 6a may be lowered too much.
In order to prevent freezing and dew condensation, a subtracter 10 calculates the deviation SE of the detected value SE from the temperature detector 9B in the stator 5 and the detected value SA from the temperature detector 98 in the cooling water tank 6.
B is compared with the deviation SF from this subtracter 10B and a preset upper limit value SG, and if the deviation SF is small, the deviation SF is output as is, and if the deviation SF is large, the upper limit value SG is output. Limiter 13 and this limiter 13
Deviation 5 of the value SH from and the deviation SF from the subtractor 10B
The subtracter 10G for calculating 1, the deviation Sl from the subtracter 10C, and the deviation SJ of the detected value SE from the temperature detector 9B.
A subtracter 100 that calculates and outputs the value to the subtracter 10A, and a heat insulating material 14 held between the stator 4 and the headstock 3 are provided.

In the above embodiment, the temperature inside the stator 5 is adjusted, but it is also possible to adjust the temperature by, for example, embedding the temperature detector 9C near the bearing 15, which is greatly affected by heat generation. .

(Effects of the Invention) As described above, according to the cooling method of the spindle built-in motor of the present invention, the temperature rise of the spindle body, headstock, etc. is suppressed to a low level, and deterioration of dimensional accuracy due to thermal expansion and poor lubrication of the bearings are prevented. It is possible to provide a spindle built-in motor that can prevent such problems and is highly accurate and reliable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram and a cross-sectional structural diagram showing an example of a cooling device and a main shaft built-in motor that realize the cooling method of the main shaft built-in motor of the present invention, and FIG. 2 is a diagram of a conventional main shaft built-in motor. FIG. 2 is a block diagram and a cross-sectional structure diagram showing an example of a cooling device and a spindle built-in motor that realize the cooling method. 1... Main shaft, 2... Rotor, 3... Headstock, 4...
...Sleeve, 5...Stator, 6...Cooling water tank, 6a...Cooling water, 7A, 7B...Pump, 8A,
8B...Piping, 9A, 98°9C...Temperature detector,
IOA, 108, 100, 100...Subtractor, 11...
Amplifier, X2...Temperature controller, 13...Limiter,
14...Insulating material, 15...Bearing. Applicant's agent Yuzo Yasugata

Claims (1)

[Claims] When cooling the motor by circulating a cooling medium through the motor incorporated in the main shaft, the temperature at a predetermined point of the motor is detected, and the deviation between this detected value and the target temperature command value is calculated to determine the temperature of the cooling medium. 1. A cooling method for a main shaft built-in motor, characterized in that the temperature-adjusted cooling medium is circulated through the motor.