JPH0553846U - Built-in motor rotor side cooling mechanism - Google Patents

Abstract

(57) [Summary] [Purpose] For example, using a tool pulling shaft in a machining center or a shaft of another device such as a power chuck drawbar in a lathe that is inserted into the center hole of the main shaft, cooling air is supplied from the rear end side of the main shaft. The rotor-side cooling mechanism of the built-in motor that can be supplied and coexists with other devices prevents the temperature of the spindle from rising and enables high-speed rotation, and also prevents accuracy deterioration due to thermal displacement of the spindle unit. [Arrangement] Air cooling passages 7a, 7b are provided between the rotor 5B and the main shaft 4 in the axial direction, and air supply holes 14a, 14b are provided in a tool pull-up shaft 14 which is fitted into the center holes 4c, 4d of the main shaft 4. , Further, the main shaft 4 is opened at the center of the air supply path 7a,
An air communication hole 4e communicating with the air supply hole 14b is provided in the radial direction, and cooling air supplied from the rear end side of the main shaft is sent from the inside to the air cooling passage 7b to cool the rotor 5B.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a rotor-side cooling mechanism fitted to a main shaft of a built-in motor.

[0002]

[Prior Art]

 In a spindle unit with a built-in motor, the heat generated by the motor is large due to the load, and the heat generated on the rotor side in particular reduces the amount of clearance in the main shaft bearing, which may lead to a seizure accident. Conventionally, as a method for cooling the built-in motor, as shown in FIG. 5, cooling water is flown through a jacket portion 102 on the outer periphery of the stator 101 to cool the motor from the outside, and as shown in FIG. There is a method of cooling the heat generation of the rotor 105 from the inside of the main shaft by the attached heat pipe 104.

[0003]

[Problems to be solved by the device]

 The method of flowing cooling water through the jacket to cool the motor from the outside as described in the conventional technique is the most common and widely used method, but it is the rotor side that leads to the temperature rise of the main shaft that affects the seizure accident. The method of cooling the spindle by mounting a heat pipe in the spindle hole has the problem that it cannot be cooled, and for example, in the case of the spindle of a machining center, it is difficult to mount the tool pulling spindle, and the spindle of the lathe In this case, it is difficult to attach a draw bar for opening and closing the power chuck, and it is difficult to coexist with other devices that operate by inserting the shaft into the spindle hole. The present invention has been made in view of these problems of the prior art, and its purpose is to be able to coexist with other devices that use a spindle hole and to cool the rotor from the inside. It is intended to provide a rotor-side cooling mechanism for a built-in motor that can reduce the temperature rise of the main spindle to release the risk of seizure accidents, and to obtain a main spindle unit that can rotate at high speed and does not deteriorate in accuracy due to thermal displacement. ..

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a rotor side cooling mechanism of a built-in motor according to the present invention includes a main shaft unit having a built-in motor and an axial cooling gas passage provided between the rotor of the built-in motor and the main shaft. A main shaft having a plurality of cooling gas communication holes that communicate with the cooling gas passage from the center side, and a main shaft that is fitted in the center hole of the main shaft and is bored in the axial direction from the rear side of the main shaft so that the tip communicates with the cooling gas. It comprises a shaft having a cooling gas supply hole communicating with the hole, and sends the cooling gas from the center side.

[0005]

[Action]

 The cooling gas is supplied from the rear side of the spindle to the cooling gas supply hole that is inserted into the spindle center hole, for example, the tool pull-up shaft or the shaft for other devices such as drawbars, and the radial direction is defined in the spindle. The cooling gas is jetted from the inside to the central part of the cooling gas passage axially provided between the rotor and the main shaft through the multiple cooling gas communication holes, and the rotor is cooled from the inside by the cooling gas flowing through the cooling gas passage. To do.

[0006]

【Example】

 Examples will be described with reference to FIGS. 1 to 4. In the spindle head of the machining center, a bearing housing 2 is fitted on the left side of the spindle head main body 1, and a plurality of bearings are fitted on the bearing housing 2 and a bearing fitted on a bracket 3 fixed on the right side of the main body 1. The main shaft 4 is rotatably supported.

A built-in motor 5 is built in the spindle head, and a built-in motor stator 5 A is fitted into a hole 1 a of the main body 1 via an outer cylinder 6, and the outer cylinder 6 has an outer periphery on which a w A data jacket groove 6a is engraved.

On the other hand, the rotor 5B of the built-in motor is fitted with an inner cylinder 7 in the center hole. The inner cylinder 7 has a large-diameter hole 7a formed at the center of the hole. A plurality of holes 7b that communicate with and are formed in the axial direction, and the small diameter hole on the right side is formed as a tapered hole. The rotor 5B is fitted in the central portion of the spindle 4 by the taper bush 8 fitted in this tapered hole, and the rotation of the rotor 5B with respect to the spindle is restricted by the key 9. The large diameter hole 7a and the holes 7b on both sides are provided in the air cooling passage. Has become.

The center hole of the spindle 4 has a left end formed in a taper hole 4a for mounting the tool T, and a hole 4b into which a collet member 11 for holding the pull stud Ta of the tool is inserted is formed following the taper hole. Subsequent to 4b, stepped holes 4a and 4d for inserting a tool pulling shaft described later are formed.

A grooved bush 12 is fitted inside the hole 4d, and the grooved bush 12 is at a position corresponding to the center of the rotor 5B. As shown in FIG. 4, the grooved bush 12 is provided with a plurality of grooves 12a through which air for cleaning the spindle taper hole 4a is engraved in the axial direction of the outer periphery, and a groove 12b through which air is encircled on one end face in the radial direction. A plurality of through holes 12c are provided in the center of the longitudinal direction and open on the outer circumference in the radial direction. Further, an air communication hole 4e communicating with the hole 12c penetrates the main shaft 4 in the radial direction.

A tool pulling up shaft 14 is fitted in the stepped holes 4 c, 4 d of the spindle 4 so as to be movable in the axial direction, and the rotation of the tool pulling up shaft 14 with respect to the spindle 4 is restricted by a rotation stop pin 15. At the same time, the coil spring 13 biases the coil member 13 to the right without any protrusion, and the left end is screwed to the collect member 11. The tool pulling shaft 14 has an air supply hole 14a drilled from the right end to the central portion. The air supply hole 14a communicates with a plurality of holes 14b drilled in the radial direction at the tip, and the hole 14b is the tool T. When pulled up, it is communicated with the through hole 12c of the grooved bush 12.

At the right end of the spindle 4, a plurality of disc springs 20 for applying a tool pulling force are fitted and inserted on both sides by collars 16 and 17 which are movable in the axial direction. 4 is compressed by the hydraulic cylinder 18 provided concentrically with the inner peripheral flange portion 18a side surface of the cylinder and the inner peripheral flange portion 19a side surface of the piston 19 via the collars 16 and 17, and the tool pulling shaft 14 A gap is made between the double nuts 21 and 22 screwed to the right end, and the edge of the disc spring and the tool pulling shaft is cut to release the tool pulling force in advance before attaching or detaching the tool.

Further, a hydraulic cylinder 23 is fixed to the right end surface of the bracket 3 in the axial direction of the main shaft, and a lever 27 is swingably supported by a pivot pin 25 on a bracket 24 fixed to the right end surface of the hydraulic cylinder 23. Accordingly, the lever 27 is swung by the movement of the piston rod 26 of the hydraulic cylinder 23 to move the tool lifting shaft 14 in the axial direction, and the tool T is attached and detached.

The rotor cooling air is supplied to the inlet of the air supply hole 14 a of the tool pulling shaft 14 by the air supply pipe 28 fixed to the main body 1, and the supplied air is the grooved bush 12. Through the hole 12c of the main shaft 4 and the connecting hole 4e of the main shaft 4 and is jetted from the inside to the central portion of the large diameter hole 7a in the center of the inner cylinder 7, passing through the gap between the main shaft 4 and the large diameter hole 7a, and from the holes 7b on both sides to the body 1 and the bracket. The rotor 5B is discharged from the outside through the discharge holes 1b and 3a of the rotor 3, and the rotor 5B is cooled from the inside.

On the other hand, the hydraulic cylinder 18 is provided with an air mounting hole 18b for cleaning the spindle taper hole 4a, and the cleaning air supplied from this hole is contained in the piston 19 which becomes airtight when the disc spring 20 is compressed. It passes through the gap, passes through the hole 16a of the collar 16, passes through the gap between the tool pulling shaft 14 and the spindle center hole, and is fed to the left side. Then, it passes through the groove portions 12a and 12b of the grooved bush 12 and is further sent to the left side to be ejected toward the tapered hole 4a so that dust or the like does not enter between the tapered hole 4a and the tool T when the tool is attached / detached. Try to sweep.

Next, the operation of this embodiment will be described. The cooling air is sent to the inlet of the air supply hole 14a from the air supply pipe 28 fixed to the main body side, and is turned in the radial direction by the hole 14b to form the hole 12c of the grooved bush 12 and the connecting hole of the spindle. 4e, the rotor is cooled from the inside while it is fed from the inside into the gap between the large diameter hole 7a of the inner cylinder 7 and the outer circumference of the main shaft, and is fed from the holes 7b on both sides. It

On the other hand, the cleaning air is sent from the hole 18b of the cylinder 18 to the space between the tool pulling shaft and the spindle center hole, and passes through the axial groove 12a formed on the outside of the grooved bush 12 to form the tapered hole. 4a, and intersects cooling air in a three-dimensional manner at right angles to the cooling air at the grooved bush portion.

[0018]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects. A cooling gas passage in the axial direction is provided between the rotor hole and the main shaft, and the cooling gas supply hole provided in the shaft, such as the tool pull-up shaft, which is fitted into the main shaft center hole, provides Cooling gas is sent from the inside to the central part of the cooling gas passage through multiple cooling gas connection holes to cool the rotor side of the built-in motor and prevent the temperature from rising, enabling high-speed rotation of the spindle. Therefore, the thermal displacement of the spindle unit is reduced and the accuracy is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a right side portion of a spindle unit with a built-in motor with a rotor-side cooling mechanism of the present embodiment.

FIG. 2 is a sectional view of a left side portion of a spindle unit with a built-in motor with a rotor-side cooling mechanism according to the present embodiment.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a perspective view of a grooved bush.

FIG. 5 is a sectional view of a conventional spindle unit with a stator-side cooling mechanism.

FIG. 6 is an explanatory view of a conventional rotor-side cooling mechanism using a heat pipe.

[Explanation of symbols]

 4 Spindle 4e Air communication hole 5 Built-in motor 5B Rotor 7 Inner cylinder 7a Air cooling passage large diameter hole 7b Air cooling passage hole 12 Groove bushing 14 Tool pulling shaft 14a, 14b Air supply hole

Claims (1)

[Scope of utility model registration request] 1. A spindle unit containing a built-in motor, wherein an axial cooling gas passage provided between a rotor of the built-in motor and a spindle and a plurality of cooling gas communication holes communicating with the cooling gas passage from the center side. And a shaft having a cooling gas supply hole that is inserted into the center hole of the main shaft and is axially bored from the rear side of the main shaft and has a tip communicating with the cooling gas communication hole. A cooling mechanism on the rotor side of a built-in motor, characterized in that cooling gas is sent from the side.