JP5676893B2 - Spindle unit - Google Patents

Description

  The present invention relates to a spindle unit including a spindle and a built-in motor that rotates the spindle.

  A conventional spindle unit including a spindle and a built-in motor that rotates the spindle has been disclosed in Patent Document 1, for example. This spindle unit is provided with a heat dissipating fin on the outer peripheral portion of the stator of the built-in motor to release heat generated from the built-in motor to the outside.

Japanese Patent Application No. 2008-296309

  By the way, in the above-described conventional spindle unit, although the heat of the built-in motor can be radiated from the radiation fin, the motor heat is transmitted to the bearing case (spindle housing) that rotatably supports the spindle, and the bearing case expands. However, there is a possibility of affecting the processing accuracy.

  Accordingly, the present invention has been devised to solve the above-described problem, and an object of the present invention is to provide a spindle unit capable of preventing the expansion of the spindle housing and improving the machining accuracy. .

The invention according to claim 1 for solving the above-mentioned problem is a spindle unit including a spindle and a built-in motor that rotates the spindle, and a spindle housing that rotatably supports the spindle via a spindle bearing; A base member that supports a motor housing that houses a built-in motor is formed separately, and the main shaft housing and the base member are connected via a heat insulating member. The heat insulating member has a washer shape, and the main shaft Bolts for fixing the housing to the base member are inserted therethrough and provided at a predetermined pitch along the outer peripheral direction of the spindle housing, and the spindle housing and the base member in which the heat insulating member is interposed during, it provided the insulation space is a gap formed between the spindle housing and said base member, It is spindle unit, characterized in that said base member and serial spindle housing is configured to be non-contact.

According to such a configuration, the heat of the built-in motor is transmitted from the motor housing to the base member, but is hardly transmitted to the main shaft housing because it is blocked by the heat insulating member. Therefore, since the thermal expansion of the main shaft housing can be prevented, the fluctuation of the tip end portion of the main shaft that affects the processing accuracy is suppressed, and the processing accuracy can be improved. Furthermore, the heat insulation effect between the main shaft housing and the base member can be further improved by providing a heat insulating space between the main shaft housing and the base member in which the heat insulating member is interposed.

The invention according to claim 2, the outer peripheral surface of the motor housing, a spindle unit according to claim 1, characterized in that a heat radiation fin.

  According to such a configuration, the heat of the built-in motor can be efficiently radiated into the air.

  According to the present invention, since the heat of the built-in motor is not transmitted to the main shaft housing, it is possible to prevent the main shaft housing from being expanded and to achieve an excellent effect that the machining accuracy can be improved.

It is the perspective view which showed embodiment of the spindle unit which concerns on this invention. It is sectional drawing which showed embodiment of the spindle unit which concerns on this invention. It is the principal part expanded sectional view which showed embodiment of the spindle unit which concerns on this invention. It is a principal part expanded sectional view which showed other embodiment of the spindle unit which concerns on this invention.

  An embodiment of a spindle unit according to the present invention will be described in detail with reference to the accompanying drawings.

  The spindle unit is provided in a column of the machine tool, and the column is configured to move the spindle as appropriate with respect to the workpiece and also to the tool magazine side to selectively attach and detach the tool held by the spindle. The

  As shown in FIGS. 1 and 2, the main shaft unit 1 includes a main shaft 10 and a built-in motor 30 that rotates the main shaft 10. Further, the spindle unit 1 includes a spindle housing 50 that rotatably supports the spindle 10 via a spindle bearing 51, and a base member 70 that supports a motor housing 31 that houses the built-in motor 30.

  As shown in FIG. 2, the main shaft housing 50 supports the main shaft 10 via a main shaft bearing 51. The main shaft housing 50 and the base member 70 are formed as separate bodies, and are connected via a heat insulating member 90.

  An attachment hole 11 for attaching / detaching the tool 2 is formed at the tip of the main shaft 10. The attachment hole 11 has a tapered shape with the diameter of the tip end being increased. Note that the shape of the tip of the spindle 10 is an example, and is not limited to this, and is appropriately formed so as to be compatible with various tool gripping part shapes such as BT, KM, HSK, etc., depending on the tool to be attached. Is done. The front portion of the main shaft 10 on the front end side is accommodated in the main shaft housing 50 and is rotatably supported by the main shaft bearing 51. A built-in motor 30 is provided at a rear portion of the main shaft 10 so as to surround the main shaft 10, and a rotor 32 of the built-in motor 30 is fixed to the outer peripheral surface of the main shaft 10.

  The main shaft 10 has a hollow structure, and a draw bar 12 that is movable in the axial direction is provided inside the main shaft 10. The draw bar 12 is arranged so that its tip protrudes from the bottom (back) of the mounting hole 11 for attaching and detaching the tool, and a grip hole 13 for gripping the end of the tool 2 is provided at the tip. Have. On the other hand, a pull stud 2 a is formed at the end of the tool 2. The grip hole 13 of the draw bar 12 has an inner diameter equivalent to the outer diameter of the pull stud 2a of the tool 2, and is configured such that the pull stud 2a can be inserted therein.

  The built-in motor 30 includes a rotor 32 formed on the outer peripheral surface of the main shaft 10 and a stator 33 that is disposed outside the rotor 32 with a predetermined interval. The stator 33 includes a coil (not shown) and is fixed to the motor housing 31. The built-in motor 30 rotates the rotor 32 by passing a current through the coil of the stator 33. The built-in motor 30 rotates the main shaft 10 directly.

  The motor housing 31 has a cylindrical shape and is disposed so as to surround the outer periphery of the stator 33. The inner peripheral surface of the motor housing 31 and the outer peripheral surface of the stator 33 are surface joined. On the outer peripheral surface of the motor housing 31, there are provided heat radiating fins 34 standing up toward the outside in the radial direction. The radiating fins 34 are formed in an annular shape extending in the circumferential direction of the motor housing 31, and a plurality of the radiating fins 34 are provided at predetermined intervals in the axial direction of the motor housing 31. The radiating fins 34 are provided to increase the surface area of the motor housing 31 and efficiently radiate the heat generated from the built-in motor 30 into the air.

  A cover body 35 that covers the entire motor housing 31 and the radiating fins 34 is provided on the outer periphery of the motor housing 31. The cover body 35 has a cylindrical shape, and is configured such that an inner peripheral surface thereof is in contact with the tips of the heat radiation fins 34. As a result, a flow path 36 surrounded by the outer peripheral surface of the motor housing 31, the adjacent radiating fins 34 and 34, and the inner peripheral surface of the cover body 35 is partitioned inside the cover body 35. The flow path 36 is formed in a plurality of rows along the circumferential direction of the motor housing 31. A first opening (not shown) is formed in an oblique upper portion of the cover body 35, and a blower fan 37 is provided in the first opening. A second opening (not shown) is formed at an oblique lower portion of the cover body 35. The second opening is formed in a portion facing the first opening across the central portion of the motor housing 31.

  In such a configuration, air is sent from the first opening to the inside of the cover body 35 by the blower fan 37, and the sent air flows through the flow path 36 inside the cover body 35 to form the second opening. It is discharged to the outside from the department. A reinforcing member 85 (see FIG. 1) that connects the horizontal base portion 71 and the rising portion 72 of the base member 70 is located on the side of the second opening, but the reinforcing member 85 has an opening 86 ( 1) is formed. Thereby, the air discharged to the outside through the second opening is discharged to the outside of the spindle unit 1 through the opening 86. The air discharged here may be collected and used as a heat source.

  The main shaft housing 50 is made of steel, for example. The main shaft housing 50 includes a cylindrical portion 52 that extends to the distal end side of the main shaft 10 and a flange portion 53 that is formed on the proximal end side of the cylindrical portion 52. In the cylindrical part 52, the main shaft 10 is rotatably accommodated via main shaft bearings 51, 51. The main shaft bearings 51 and 51 are provided at the distal end portion and the base end portion of the cylindrical portion 52, respectively, and support the main shaft 10. The flange portion 53 is formed in a circular band shape and is formed orthogonal to the axial direction of the cylindrical portion 52. In the flange portion 53, through holes 53a for bolts are arranged and formed concentrically at predetermined intervals.

  The base member 70 is configured by a saddle that fixes the main shaft 10 to a machine tool (not shown). The base member 70 (saddle) is attached to an elevating part (not shown) provided in a column (not shown) of the machine tool so as to be movable back and forth along the axial direction of the main shaft 10. The base member 70 includes a horizontal base portion 71 that extends in the horizontal direction and a rising portion 72 that rises orthogonally upward from one end of the horizontal base portion 71 and has an L shape in side view. Yes. A reinforcing member 85 (see FIG. 1) is provided at a connection portion between the horizontal base portion 71 and the rising portion 72. The reinforcing member 85 is composed of plates raised at both ends in the width direction of the horizontal base portion 71, the lower end is connected to the horizontal base portion 71, and the front end is connected to the rising portion 72. The base member 70 is connected to the machine tool main body side with the horizontal base 71 fixed to the elevating part. On the other hand, the spindle housing 50 and the motor housing 31 are fixed to the rising portion 72.

  A through hole 73 through which the main shaft 10 is inserted is formed at the center of the rising portion 72. The through hole 73 is formed to have a diameter larger than that of the main shaft 10, and the tip of the motor housing 31 is accommodated inside the through hole 73. The front end of the motor housing 31 is formed with a cylindrical portion 31 a that protrudes forward. The cylindrical portion 31 a is inserted into the through hole 73, and the motor housing 31 is fixed to the rising portion 72. Yes. Bolt holes 74 for fixing the spindle housing 50 are formed on the front surface of the peripheral edge of the through hole 73 of the rising portion 72 (the surface facing the flange 53 of the spindle housing 50). A plurality of bolt holes 74 are provided, and are respectively formed at positions corresponding to the through holes 53 a of the spindle housing 50.

  A concave portion 75 is formed on the upper surface of the horizontal base portion 71. The recess 75 is formed at a position below the built-in motor 30 and is configured to accommodate the motor housing 31 and the lower ends of the cover body 35. A cover 38 is provided at the rear end of the motor housing 31 to cover the rear end opening. The cover 38 includes a through hole through which the rear end portion of the main shaft 10 is inserted. A rotation sensor 76 that detects the amount of rotation of the main shaft 10 is provided at the rear portion of the cover 38. The cover 38 is provided with a gap from the main shaft 10. Thereby, it is possible to prevent the heat generated by the operation of the built-in motor 30 from being transmitted to the main shaft 10.

  As shown in FIGS. 2 and 3, the heat insulating member 90 is interposed between the flange portion 53 of the spindle housing 50 and the rising portion 72 of the base member 70. The heat insulating member 90 is made of a material having a predetermined strength and heat insulating properties. The heat insulating member 90 has a washer shape having a predetermined thickness, and a bolt 91 for fixing the spindle housing 50 to the base member 70 is inserted therethrough. A plurality of heat insulating members 90 are provided at a predetermined pitch, and are arranged for each bolt 91. One surface of the heat insulating member 90 is in contact with the flange portion 53 of the spindle housing 50, and the other surface is in contact with the rising portion 72 of the base member 70, thereby serving as a spacer. As a result, the heat insulating member 90 is sandwiched between the flange portion 53 of the spindle housing 50 and the rising portion 72 of the base member 70, and an air layer 92 serving as a heat insulating space is formed.

  According to the spindle unit 1 configured as described above, the spindle housing 50 and the base member 70 that supports the motor housing 31 are formed separately, and the spindle housing 50 and the base member 70 are connected via the heat insulating member 90. Therefore, although the heat generated by the operation of the built-in motor 30 is transmitted from the motor housing 31 to the base member 70, the heat transfer is reduced by the heat insulating member 90 and hardly transmitted to the spindle housing 50. Further, since the heat insulating member 90 serves as a spacer between the flange portion 53 of the spindle housing 50 and the rising portion 72 of the base member 70, there is a gap in a portion other than the heat insulating member 90 interposed, and air Layer 92 is formed. Thereby, the heat insulation effect between the spindle housing 50 and the base member 70 is further improved.

  Thus, according to the present embodiment, heat transfer to the spindle housing 50 can be greatly reduced, so that thermal expansion of the spindle housing 50 can be prevented, and the position of the spindle bearing 51 in the spindle housing 50 does not change. Here, since the main shaft 10 is pivotally supported by a main shaft bearing 51 provided inside the main shaft housing 50, the main shaft 10 does not generate a deviation in the rotation of the main shaft 10 and may affect the machining accuracy. Fluctuations in the tip of the are suppressed. Therefore, the processing accuracy can be improved.

  Further, in the present embodiment, the base member 70 is constituted by a saddle that fixes the main shaft 10 to the machine tool, a horizontal base portion 71 that serves as a saddle, and a rising portion 72 to which the main shaft housing 50 and the motor housing 31 are attached. However, the strength necessary for supporting each member (the spindle housing 50, the motor housing 31, etc.) can be ensured while reducing the weight as a whole. That is, conventionally, since the base member is configured as a separate member from the saddle, the horizontal base portion of the saddle and the base member is formed overlappingly, and the weight increases. On the other hand, when only the rising portion is connected to the saddle, the strength of the connecting portion between the saddle and the rising portion is weak, and the required strength cannot be ensured, but this embodiment has these problems. It is solved together.

  Furthermore, in the present embodiment, the concave portion 75 is formed on the upper surface of the horizontal base portion 71, and the lower end portions of the motor housing 31 and the cover body 35 are accommodated in the concave portion 75. The overall height dimension can be reduced. As a result, the spindle unit 1 can be made more compact and lighter.

  Furthermore, in this embodiment, the heat radiation fin 34 is provided on the outer peripheral surface of the motor housing 31, covered with the cover body 35, and the air generated by the blower fan 37 is passed through the inside thereof, thereby efficiently generating heat generated from the built-in motor 30. It can dissipate heat well into the air.

The best embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that the design can be changed as appropriate without departing from the spirit of the present invention. For example, in this embodiment, the bolt 91 for fixing the spindle housing 50 to the base member 70 is made of ordinary steel, but a heat insulating bolt formed of a heat insulating material may be used. In this way, the amount of heat transferred to the spindle housing 50 can be further reduced.

Next, a reference embodiment of the spindle unit will be described in detail with reference to FIG. In the embodiment, the heat insulating member 90 is provided between the main shaft housing 50 and the base member 70, whereas in the present embodiment, the heat insulating member 95 is interposed between the base member 70 and the motor housing 31. It is characterized by being. Since other configurations are the same as those in the above embodiment, the same reference numerals are given and description thereof is omitted.

  The heat insulating member 95 is provided between the rising portion 72 of the base member 70 and the motor housing 31. The heat insulating member 95 includes a rear surface (a surface facing the motor housing 31) of the peripheral portion of the through hole 73 of the rising portion 72 and a front surface (on the rising portion 72) located at the base end portion of the cylindrical portion 31 a of the motor housing 31. Between the opposite surfaces). The heat insulating member 95 is made of a material having predetermined strength and heat insulating properties. The heat insulating member 95 has an annular shape and is provided so as to surround the cylindrical portion 31a. The main shaft housing 50 and the base member 70 are directly connected. The heat insulating member 95 is not limited to an annular shape, and a plurality of the heat insulating members 95 may be provided at predetermined intervals in the circumferential direction. In this case, an air layer serving as a heat insulating space is formed between adjacent heat insulating members.

  According to the configuration described above, the heat insulating effect 95 can be obtained between the base member 70 and the motor housing 31 by providing the heat insulating member 95 between the rising portion 72 of the base member 70 and the motor housing 31. Therefore, the heat generated by the operation of the built-in motor 30 is reduced in heat transfer to the base member 70 by the heat insulating member 95 and hardly transmitted to the spindle housing 50. As a result, the same effects as those of the above-described embodiment can be obtained, and the processing accuracy can be improved.

DESCRIPTION OF SYMBOLS 1 Main shaft unit 10 Main shaft 30 Built-in motor 31 Motor housing 34 Radiation fin 50 Main shaft housing 51 Main shaft bearing 70 Base member 90 Heat insulation member 92 Air layer (heat insulation space)
95 Thermal insulation material

Claims (2)

In a spindle unit that includes a spindle and a built-in motor that rotates the spindle,
A spindle housing that rotatably supports the spindle via a spindle bearing and a base member that supports a motor housing that houses the built-in motor are formed separately.
While connecting the main shaft housing and the base member via a heat insulating member,
The heat insulating member has a washer shape, a bolt for fixing the spindle housing to the base member is inserted therethrough, and is provided at a predetermined pitch along the outer peripheral direction of the spindle housing.
A heat insulating space that is a gap formed between the main shaft housing and the base member is provided between the main shaft housing and the base member in which the heat insulating member is interposed, and the main shaft housing and the base member are not in contact with each other. A spindle unit characterized by being configured as follows. The spindle unit according to claim 1, wherein heat dissipating fins are provided on an outer peripheral surface of the motor housing.

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