JP6380041B2 - Spindle device - Google Patents

Description

  The present invention relates to a spindle device including a spindle to which a tool is attached.

  A machine tool processes a workpiece by rotationally driving a tool attached to a spindle. The main shaft is rotatably supported by the main shaft housing. The tool is attached to the lower end portion of the main shaft that protrudes outside the main shaft housing. The machine tool includes a coolant supply device that supplies coolant to a workpiece being processed. The coolant removes frictional heat generated between the rotating tool and the workpiece, and prevents the tool and workpiece from overheating. Tool life and workpiece machining accuracy are improved by supplying coolant.

  The spindle device of the machine tool described in Patent Document 1 is provided with a labyrinth portion between the spindle and the spindle housing, and prevents air from entering the coolant by ejecting air from a gap between the spindle and the spindle housing. ing.

  The spindle device includes an end surface cover fixed to the peripheral edge portion of the lower end of the spindle and a spindle cover fixed to the lower end of the spindle housing. The end face cover and the spindle cover form a labyrinth portion.

JP 2010-076045 A

  If the spindle is not balanced, the spindle will vibrate during rotation, reducing the machining accuracy of the workpiece. In order to suppress the vibration of the main shaft, it is necessary to keep the main shaft balanced. Therefore, a hole is provided in the main shaft, and a weight, such as a screw, that keeps the balance in the hole is inserted. However, when the hole is provided, wind noise is easily generated when the main shaft rotates.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a spindle device that maintains the balance of the spindle and suppresses the generation of wind noise.

  A spindle apparatus according to the present invention includes a spindle that rotates about an axis, an annular end surface cover that is fixed to an outer peripheral portion of a lower end portion of the spindle, and a weight that is provided on the spindle and maintains the balance of the spindle. A spindle device including an equilibrium hole to be attached is provided with a through hole provided at a position corresponding to the equilibrium hole of the end surface cover, and a lid for closing the through hole.

  In the present invention, a weight is attached to the balance hole to maintain the balance of the main shaft, and a lid is provided to the through hole of the end surface cover to prevent wind noise.

  The spindle device according to the present invention is characterized in that the weight has a smaller diameter than the lid, and the through hole has a larger diameter than the balance hole.

  In the present invention, the weight is smaller in diameter than the lid and the through-hole is larger in diameter than the equilibrium hole, so that the spindle is kept in equilibrium by attaching the weight to the equilibrium hole with the end face cover attached to the main shaft and penetrating the lid. Can be attached to the hole. When the diameter of the through hole is equal to or smaller than the diameter of the balanced hole, the weight is attached to the balanced hole with the end face cover removed, and then the end face cover must be attached to the main shaft.

  The spindle device according to the present invention is characterized in that the lid is a screw having a head, and the through-hole has a countersink portion for accommodating the head.

  In the present invention, it is possible to prevent the head portion of the lid from protruding from the end surface cover by forming the counterbore portion in the through hole.

  In the spindle device according to the present invention, a weight can be attached to the balancing hole to keep the spindle balanced, and a lid can be provided in the through hole of the end surface cover to suppress the generation of wind noise.

It is a side view which shows the attachment state of the spindle apparatus of a machine tool. It is sectional drawing of the front-end | tip part of a main shaft and a main shaft housing. It is a bottom view which shows a main axis | shaft and an end surface cover. FIG. 4 is a combined cross-sectional view taken along line IV-IV shown in FIG. 3.

  Hereinafter, the present invention will be described based on the drawings showing a spindle device according to an embodiment. FIG. 1 is a side view showing a mounting state of a spindle device of a machine tool, and FIG. 2 is a cross-sectional view of the spindle and the tip portion of the spindle housing.

  As shown in FIG. 1, the spindle device 1 of the present invention includes a spindle housing 3 attached to the tip end portion (left end portion in FIG. 1) of the spindle head 2. The spindle head 2 includes two guide portions 2a and 2a and one nut portion 2b at a base end portion (right end portion in FIG. 1). The two guide portions 2a and 2a support the spindle head 2 on a vertical column (not shown) provided on the machine tool. The nut portion 2b is screwed to a vertical screw shaft (not shown) provided on the column.

  The screw shaft is rotated by driving a Z-axis motor (not shown). The spindle head 2 including the nut portion 2b moves in the direction (vertical direction) of the screw shaft as the screw shaft rotates. The guide portions 2a and 2a guide the movement of the spindle head 2 in the vertical direction.

  As shown in FIG. 2, the main shaft housing 3 has a cylindrical shape that supports the main shaft 11 rotatably at the center thereof. The main shaft 11 is an axis extending in the vertical direction. The spindle 11 rotates by driving a spindle motor (not shown).

  The lower end of the spindle housing 3 is covered with an annular spindle cover 8. The spindle cover 8 is fixed to the lower end surface of the spindle housing 3 with a plurality of bolts (not shown). A part of the lower surface of the spindle cover 8 (excluding the inner peripheral portion and the outer peripheral portion) is covered with an annular nozzle forming member 12. The nozzle forming member 12 is fixed to the lower surface of the spindle cover 8 with a plurality of bolts (not shown).

  The spindle 11 protrudes below the spindle housing 3 through the center hole of the spindle cover 8. The main shaft 11 has a tool mounting hole 11a at the center of the lower end surface. The tool mounting hole 11a is a tapered hole whose diameter decreases upward. The tool (not shown) is held by a conical tool holder (not shown). The spindle device 1 can attach a tool to the lower end of the spindle 11 by inserting the tool holder into the tool attachment hole 11a.

  The nozzle forming member 12 has a plurality of nozzle holes 12b in the inner peripheral portion of the lower surface. The plurality of nozzle holes 12b communicate with the coolant chamber 12c. The coolant is ejected downward through the coolant chamber 12c and the nozzle hole 12b. The nozzle hole 12 b ejects the coolant obliquely toward the center of the main shaft 11. The jetted coolant hits the workpiece processed by the tool.

  As shown in FIG. 2, an annular end surface cover 13 fixed with a fixing screw 51 (see FIG. 3) is provided on the outer peripheral portion of the lower end surface of the main shaft 11. The end surface cover 13 projects outward from the outer periphery of the main shaft 11. The projecting portion of the end surface cover 13 is opposed to the inner peripheral portion of the spindle cover 8 via a gap. The outer periphery of the end surface cover 13 is opposed to the inner periphery of the center hole of the nozzle forming member 12 via a gap.

  The spindle device 1 includes a labyrinth portion 21 at a facing portion between the end surface cover 13 and the spindle cover 8 and a facing portion between the end surface cover 13 and the nozzle forming member 12.

  An air chamber 19 is provided between the inner peripheral surface of the main shaft cover 8 and the outer peripheral surface of the main shaft 11. The spindle cover 8 is provided with an air supply hole 20 penetrating in the radial direction. The air chamber 19 communicates with the air supply hole 20 and the labyrinth portion 21.

  The air supply hole 20 is connected to a compressed air supply circuit (not shown) through an opening on the outer periphery of the spindle cover 8. The compressed air enters the labyrinth portion 21 through the air supply hole 20 and the air chamber 19 and blows out from the gap between the end surface cover 13 and the spindle cover 8.

  3 is a bottom view showing the main shaft 11 and the end surface cover 13, and FIG. 4 is a combined sectional view taken along line IV-IV shown in FIG.

  Four attachment holes 11 b for attaching the fixing screw 51 are provided on the lower end surface of the outer peripheral portion of the main shaft 11. The four mounting holes 11b are provided at equal intervals of 90 degrees around the axis of the main shaft 11. A screw is formed in the mounting hole 11b.

  In addition, on the lower end surface of the outer peripheral portion of the main shaft 11, six balancing holes 11c for attaching the balancing screw 53 are provided. The six balance holes 11c are provided at equal intervals of 60 degrees around the axis of the main shaft 11. Of the six balancing holes 11c, the four balancing holes 11c are positioned next to the four mounting holes 11b, respectively. The six balance holes 11c are internally formed with screws.

  The end face cover 13 is provided with four through-holes 13a through which the fixing screws 51 are inserted at positions corresponding to the attachment holes 11b. The attachment hole 11b and the insertion hole 13a are continuous in the axial direction. A counterbore 13b is formed at the lower end of the insertion hole 13a. The diameter of the insertion hole 13a is larger than the mounting hole 11b.

  The end surface cover 13 is provided with six through holes 13c into which the lid screws 52 are inserted at positions corresponding to the balance holes 11c. The balance hole 11c and the through hole 13c are continuous in the axial direction. A counterbore 13d is formed at the lower end of the through hole 13c. The diameter of the through hole 13c is larger than that of the equilibrium hole 11c. The through hole 13c has a screw formed inside.

  The fixing screw 51 has a head portion 51a and a shaft portion 51b protruding in the axial direction from the head portion 51a. The diameter of the head portion 51a is larger than that of the shaft portion 51b. The diameter of the head 51a is the same as the diameter of the countersunk portion 13b and is larger than the diameter of the portion excluding the countersink 13b of the insertion hole 13a. The diameter of the shaft portion 51b is smaller than the diameter of the portion excluding the counterbore portion 13b of the insertion hole 13a. The fixing screw 51 is a tapping screw.

  The fixing screw 51 is inserted into the insertion hole 13a, and the shaft portion 51b is coupled to the mounting hole 11b. The head 51a is located in the counterbore 13b. The head 51a and the lower surface of the end surface cover 13 are flush with each other. The fixing screw 51 connects the end surface cover 13 and the main shaft 11.

  The balancing screw 53 (weight) is a tapping screw without a head, and is attached to the balancing hole 11c as necessary in order to balance the main shaft 11. The axial dimension of the balancing screw 53 is shorter than the axial dimension of the balancing hole 11c. Since the diameter of the balancing screw 53 is smaller than that of the through hole 13c, the balancing screw 53 can be inserted into the through hole 13c and attached to the balancing hole 11c with the end surface cover 13 attached to the main shaft 11. Of the six balancing holes 11c, the balancing screw 53 is attached only to the balancing hole 11c necessary for balancing the main shaft 11, so the balancing screw 53 may not be attached to the balancing hole 11c.

  The lid screw 52 (lid) is a tapping screw, and has a screw portion 52a and a flange portion 52b (head) provided at an end of the screw portion 52a. The diameter of the flange part 52b is larger than the diameter of the screw part 52a, and is the same as the diameter of the countersink part 13d. The axial dimension of the flange 52b is the same as the axial dimension of the counterbore 13d. The axial dimension of the screw portion 52a is the same as the axial dimension of the portion excluding the counterbore 13d of the through hole 13c.

  The screw portion 52a is attached to a portion of the through hole 13c excluding the countersink portion 13d. When the lid screw 52 is attached to the through hole 13c, the flange portion 52b is located in the counterbore portion 13d. The flange portion 52b and the lower surface of the end surface cover 13 are flush with each other, and the flange portion 52b does not protrude from the end surface cover 13. The lid screw 52 closes the balance hole 11c and the through hole 13c. All through-holes 13c are provided with lid screws 52, and the weights of the lid screws 52 are the same.

  In the spindle device 1 according to the embodiment, a balancing screw 53 (weight) is attached to the balancing hole 11c, the balance of the spindle 11 is maintained, and a lid screw 52 is provided in the through hole 13c of the end surface cover 13, so that wind noise is generated. Suppress. For example, when the spindle 11 is rotating at 27000 rpm and the microphone position is set at a position 1 m away from the front of the machine tool and noise is measured, the measures against wind noise are taken. The equivalent noise was reduced by about 3.5 dB, and the loudness was reduced by about 5.4 sound.

  Since the balancing screw 53 has a smaller diameter than the lid screw 52 and the through hole 13c has a larger diameter than the balancing hole 11c, the balancing screw 53 is attached to the balancing hole 11c with the end surface cover 13 attached to the main shaft 11. The balance of the main shaft 11 can be maintained, and the lid screw 52 can be attached to the through hole 13c. When the diameter of the through hole 13c is equal to or smaller than the diameter of the balancing hole 11c, the balancing screw 53 must be attached to the balancing hole 11c with the end face cover 13 removed, and then the end face cover 13 must be attached to the main shaft 11.

  By forming the counterbore 13d in the through hole 13c, it is possible to prevent the flange 52b (head) of the lid screw 52 from protruding from the end surface cover 13, and to reduce the cause of wind noise. Since the flange portion 52b is flush with the end surface cover 13, it is possible to effectively prevent the generation of wind noise.

  In addition, since the six balance holes 11c are provided at equal intervals of 60 degrees around the axis of the main shaft 11, the lid screw 52 corresponding to the balance hole 11c is also 60 degrees around the axis of the main shaft 11. It is provided at equal intervals. The weights of the lid screws 52 are the same. Therefore, even when the balancing screw 53 is attached to the balancing hole 11c and the main shaft 11 is balanced, and then the lid screw 52 is attached to each through-hole 13c, the main shaft 11 maintains the balance.

  The number of balance holes 11c is not limited to six. A plurality of balance holes 11c may be provided around the axis of the main shaft 11 with a predetermined angle and the like. For example, the number of balance holes 11c may be four or eight.

DESCRIPTION OF SYMBOLS 1 Main shaft apparatus 3 Main shaft housing 8 Main shaft cover 11 Main shaft 11c Equilibrium hole 13 End surface cover 13c Through hole 13d Countersink part 52 Screw for lid (lid)
52a Screw part 52b Flange part (head)
53 Equilibrium screw (weight)

Claims (3)

A spindle device comprising: a spindle that rotates about an axis; an annular end surface cover that is fixed to an outer peripheral portion of a lower end portion of the spindle; In
A plurality of the balancing holes are arranged at regular intervals around the axis of the main shaft,
A plurality of through holes are provided at positions corresponding to said plurality of balancing holes in the end face cover,
And a plurality of lids for closing all the plurality of through holes,
The lower surfaces of the lid and the end surface cover are flush with each other,
Weight of each lid spindle and wherein the same der Rukoto. The weight has a smaller diameter than the lid,
The spindle device according to claim 1, wherein the through hole has a larger diameter than the balance hole. The lid is a screw having a head;
The spindle device according to claim 2, wherein the through hole has a countersink portion that accommodates the head.

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