JP2593073Y2 - Motor cooling device built into the spindle head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a built-in motor built in a spindle head.

[0002]

2. Description of the Related Art Conventionally, there has been known a spindle head of a machine tool in which a rotor of a built-in motor is shrink-fitted and mounted on the outer periphery of a spindle, and the spindle is directly driven to rotate by the built-in motor.

In a spindle head of a machine tool having an automatic tool attaching / detaching mechanism, a structure is used in which a tapered tool attaching / detaching portion in which a tool holder is detachable and a tool holder tightening means are provided at the tip of the spindle. ing. This tightening means grips the pull stud at the rear of the tool holder, supports the collet, and pulls the tool holder into the spindle head via a drawbar to which a pulling force is applied by a flat spring, or presses the drawbar against the flat spring. And a hydraulic cylinder for detaching the tool holder.

[0004]

However, a means such as cooling with an oil jacket on the stator side of the built-in motor is provided on the main shaft head of the conventional machine tool to which the built-in motor is mounted. On the rotor side mounted on the vehicle, there was no effective cooling means provided by heat generation, so that a reduction in machining accuracy due to thermal displacement of the main shaft could not be avoided.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an effective cooling means for preventing heat generation of a rotor of a built-in motor built in a spindle head of a machine tool. It is in.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a spindle which is rotatably supported on a spindle head, and has a tapered tool attachment / detachment in which a tool holder can be attached / detached at the tip of the spindle. A tool for holding a pull stud at the rear of the tool holder, supporting the collet, and pulling the tool holder into the spindle head via a drawbar to which a pulling force is applied by a flat spring, or pushing the draw bar against the flat spring. A tightening means consisting of a hydraulic cylinder for releasing the tool holder by releasing the collet is provided on the spindle head of a machine tool configured to directly rotate and drive the spindle by a built-in motor built in the spindle head. In the built-in motor cooling device, the hydraulic cylinder is fixed to a rear end portion of a spindle head, and a cylinder having an air passage hole formed therein. And a piston which is slidably inserted into the cylinder and has a conducting hole formed in a portion sliding with the cylinder and communicating with a conducting hole of the cylinder, and the drawbar has a hydraulic cylinder side. An air passage passing through an axial center having an open end, and an air passage communicating with the air passage and radially penetrating toward a chamber for accommodating the spring, are formed in the main shaft, and a chamber for accommodating the spring. An air passage communicating between the motor housing and the chamber for housing the motor is formed, and an air passage communicating the motor housing with the outside air is formed at the spindle head. Are connected.

[0007]

The present invention constructed as described above operates as follows.

Compressed air supplied from an external air supply device passes through the axis of the drawbar, passes through an air passage penetrating radially from the shaft hole at the back of the drawbar, and passes through a chamber for accommodating the spring. Further, the rotor fitted to the drawbar is cooled. Then, the air flows along the air passage in the radial direction toward the room accommodating the built-in motor, and discharges the heated air to the outside air.

[0009] The drawbar shaft is guided through a hole penetrating in the radial direction to the chamber for accommodating the spring by the pressure of the compressed air and the centrifugal force generated when the main shaft rotates.
In addition, the flow of air from the chamber for storing the Sarah spring to the chamber for storing the built-in is generated by Bernoulli's theorem from the pressure of the compressed air, the centrifugal force generated in the air when the main shaft rotates, and the speed difference caused by the main shaft rotation. It is caused by three factors of the pressure difference between the air in the flat spring and the air in the built-in motor storage chamber. For this reason, it is important to introduce the compressed air into the axis of the drawbar and sequentially guide the compressed air to a passage having a large diameter in the radial direction. Disturbing this forward path impedes the flow of air.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a main shaft 2 by a built-in motor 10.
1 is a cross-sectional view showing a vertical cross section of a spindle head 1 configured to directly drive a rotary shaft. In the figure, a spindle 2 is rotatably supported by a spindle head 1 and has a tapered tool attaching / detaching portion at the tip of the spindle 2 to which a tool holder can be attached / detached. The pull stud 3a at the rear of the tool holder 3 is gripped by the collet 5d by a tightening means provided with a hydraulic cylinder 6 that presses the draw bar 5 against the flat spring 4, and the pull bar 5 to which the pulling force is applied by the flat spring 4 is applied. It is configured to be drawn into the tool attaching / detaching portion.

Reference numeral 20 denotes a nozzle for guiding compressed air from an external air supply device to the spindle head 1. A conduction hole 6b provided in the cylinder 6a of the hydraulic cylinder 6 and a conduction hole 6d provided in the piston 6c are provided in the tool holder. Piston 6 to release 3
When c moves forward, it is conducted to the axial passage 5a of the drawbar 5, so that the cooling air flows into the spindle head 1 even when the spindle 2 is stationary. The cylinder 6a is provided with an air communication hole 6g communicating with a cylinder chamber 6f on the rear side of the piston 6c. 6f to hold the piston 6c in the retracted position. As a result, while the main shaft 2 is rotating, the rear end of the drawbar 5 on the hydraulic cylinder 6 side is moved to the piston 6 c of the hydraulic cylinder 6.
Is reliably prevented from contacting.

The draw bar 5 is provided with an air passage 5a passing through its axis and an air passage 5b penetrating in the radial direction.
This passage 5b is in communication with the chamber 7 in which the spring 4 is stored. Room 8 for storing built-in motor 10 and Sarabane 4
Is conducted through a hole 9 provided through the main shaft 2. The air that has flowed into the chamber 8 that houses the built-in motor 10 further passes through the air passage 11 and discharges air that has been heated to outside air by a fan or the like.

The cooling device configured as described above operates as follows.

The compressed air supplied from an external air supply device is guided from the nozzle 20 to a conduction hole 6b provided in the cylinder 6a of the hydraulic cylinder 6. This compressed air flows into the cylinder chamber 6f through the air communication hole 6g during the tool clamping, and holds the piston 6c at the retracted position. When the piston 6c moves forward and comes into contact with the end of the draw bar 5 to release the tool holder 3, the compressed air flows through the communication holes 6e, 6e.
d, flows into the axial passage 5a, and further flows into the chamber 8 through the passage 5b, the chamber 7, and the hole 9, and the built-in motor 1
0 is cooled and discharged from the air passage 11.

[0016]

[Effects of the Invention] As described above, according to the motor cooling device incorporated in the spindle head of the present invention, the air is actively flowed into the chamber for accommodating the Sarah spring, so that the built-in motor incorporated in the spindle head is provided. Heat generation can be prevented. Further, according to the present invention, an air passage is formed using a hydraulic cylinder that releases a tool holder, and cooling air can flow to a built-in motor storage chamber through an air passage of a drawbar. An effective cooling action can be produced with a simple structure without adding the member described above. Also, since the piston can be held at the retracted position by using the supplied air pressure, a special mechanism for holding the piston at the retracted position is not required, and an excellent effect that the structure of the hydraulic cylinder is simplified is achieved. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

[Explanation of symbols]

 3 Tool holder 4 Sara spring 5 Drawbar 5b Air passage

Claims (2)

(57) [Scope of request for utility model registration] 1. A spindle which is rotatably supported on a spindle head, is provided with a tapered tool attaching / detaching portion at a tip of the spindle which allows a tool holder to be attached / detached, and grasps a pull stud at a rear portion of the tool holder. The tool holder is pulled into the spindle head through a drawbar that supports the collet and is given a pulling force by a spring, or the drawbar is pressed against the spring, to loosen the collet and release the tool holder. A cooling device for a motor built in a spindle head of a machine tool configured to provide a tightening means formed of a hydraulic cylinder to be driven and to directly rotate and drive the spindle by a built-in motor built in the spindle head, wherein the hydraulic cylinder comprises a spindle. It consists of a wall fixed to the rear end of the head and a cylindrical part having a cylinder chamber inside, and the inside of the cylindrical part and the wall communicates with air. A cylinder having a conduction hole formed therein, a rod portion slidably inserted into a cylinder chamber of the cylinder, penetrating the wall portion, communicating with the conduction hole of the cylinder through the rod portion, and A piston provided with an air passage hole passing through an axial center having an open end at the side thereof, and an air passage passing through an axial center having an open end at the hydraulic cylinder side; An air passage is formed in the main shaft so as to radially penetrate toward the chamber that houses the salar spring, and an air passage that communicates the chamber that houses the spring and the chamber that houses the motor is formed in the main shaft. An air passage communicating with the motor storage chamber and the outside air is formed in the spindle head, and an air supply device is connected to an air passage hole of the cylindrical portion of the hydraulic cylinder, and the air in the wall is empty. A cooling device for a motor built in a spindle head of a machine tool, wherein the air passage hole has a branch passage communicating with a back side of the piston of the cylinder chamber. 2. The hydraulic cylinder according to claim 1, further comprising an air communication hole communicating with the communication hole of the piston, and an air communication hole communicating with the cylinder chamber on the back side of the piston. Item 2. A cooling device for a motor built in a spindle head of a machine tool according to item 1.