JP4431848B2 - Spindle device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spindle device that supplies coolant to a tool holder clamped by a draw bar.
[0002]
[Prior art]
Conventionally, in order to supply coolant from the coolant supply means installed at the rear of the spindle device to the tool holder clamped at the tip of the spindle by a draw bar biased in the clamping direction, a through hole and a spindle formed in the axis of the draw bar A coolant supply path is formed in the main shaft and the draw bar, and the coolant is supplied from the coolant supply means to the tool holder via the coolant supply path. Is known (Japanese Patent Laid-Open No. 10-225845).
[0003]
[Problems to be solved by the invention]
However, when the hydraulic pressure of the coolant supplied from the coolant supply means is applied to the front side wall surface of the through hole formed in the axis of the draw bar, a force in the unclamping direction of the tool holder is generated on the draw bar by the hydraulic pressure of the coolant. As a result, the clamping direction force of the draw bar generated by the urging means is reduced, and the tool holder cannot be firmly clamped to the tip of the main shaft, leading to a decrease in machining accuracy.
[0004]
Further, in a spindle device of a machine tool configured such that a spindle shaft motor shaft is a hollow shaft, a coolant supply means is connected to a rear end portion of the hollow shaft, and a main shaft having a draw bar is connected to a front end portion. Is provided with a holding state release mechanism that pushes the draw bar urged in the clamping direction forward in the axial direction (unclamping direction) in order to replace the tool holder, and the holding state release mechanism passes through the coolant supply path. Since the draw bar is pushed forward in the axial direction through the pin member fitted so as to penetrate, the hydraulic pressure of the coolant is also applied to the pin member in addition to the front side wall surface of the through hole described above. As a result, a large unclamping direction force is generated, and there is a risk that the spindle device may be damaged due to a decrease in machining accuracy and a loosening of the tool holder. Therefore, an object of the present invention is to provide a spindle device in which coolant is supplied in a state where a tool holder clamped by a draw bar biased in a clamping direction is securely clamped.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present application uses a main shaft driving motor shaft as a hollow shaft, a coolant supply means is connected to the rear end portion of the hollow shaft, and a main shaft having a draw bar is connected to the front end portion. Includes a biasing means for pulling the draw bar rearward in the axial direction and clamping the tool holder to the front end of the main shaft, and passing the coolant from the coolant supply means to the main shaft and the draw bar via a coolant supply path provided on the main shaft and the draw bar. In the spindle device supplied to the holder, a pin member is fitted into the draw bar so as to pass through the coolant supply path, and the draw bar is pushed forward in the axial direction through the pin member to release the holding state of the tool holder. A coolant supply path for a draw bar that is provided with a state release mechanism and is drawn rearward in the axial direction by an urging means, and The unclamping direction force to the tool holder caused by the liquid pressure of the coolant according to the pin member of the lifting state release mechanism, provided with a bucking force generating mechanism that causes the force to cancel out by the liquid pressure of the coolant.
[0009]
The counteracting force generating mechanism was installed on the rear side of the main shaft from the biasing means for pulling the draw bar rearward in the axial direction and clamping the tool holder to the front end of the main shaft. Specifically, the holding mechanism of the tool holder can be maintained by pulling the draw bar backward in the axial direction and urging means for clamping the tool holder to the front end of the main spindle and pushing the draw bar forward in the axial direction. It was installed between the pin members of the holding state releasing mechanism to be released.
[0010]
In addition, a large-diameter portion larger in diameter than the abutting portion with which the urging member abuts is provided at the rear of the draw bar so as to slide inside the large-diameter hole opened to the rear of the main shaft. A seal member is provided on the inner side of the main shaft where the contact part slides, and a cylinder chamber is formed between the front end surface of the large-diameter portion and the end surface of the large-diameter hole. The cylinder chamber is supplied to the tool holder from the coolant supply path. A counteracting force generating mechanism is configured by communicating with the communication path so as to supply a part of the coolant to be supplied.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments will be described with reference to the drawings. A spindle apparatus 1 shown in FIG. 1 is configured by connecting a coolant supply means 3 to the rear of a spindle driving motor 2 and connecting a spindle 6 to which a tool holder 5 is clamped by a draw bar 4 to the front. . The spindle device 1 is provided with a holding state releasing mechanism 7 that can release the clamped state of the tool holder 5 by pushing the draw bar 4 forward in order to replace the tool holder 5. First, the main shaft 6 will be described. The main shaft 6 is rotatably supported by a plurality of bearings 9 provided in the main shaft head 8. A tapered hole 10 is formed at the tip of the main shaft 6, and the tool holder 5 is mounted in the tapered hole 10. The tool holder 5 is provided with a coolant channel 5a so as to supply coolant to a cutting tool such as a drill held by the tool holder 5. A through hole 11 having a small diameter hole 11a in the front is formed in the shaft center of the main shaft 6 so as to be continuous with the tapered hole 10, and a large diameter opened to the rear of the main shaft 6 behind the through hole 11. The hole 12 is continuously provided.
[0012]
In addition to the tapered hole 10, a through hole 13 for supplying coolant to the coolant channel 5 a of the tool holder 5 attached to the tapered hole 10 is formed in the tip end portion of the main shaft 6 in a substantially axial direction. The rear end side of the main shaft 6 of the through hole 13 communicates with a through hole 14 in a direction orthogonal to the main shaft axis opened toward the inside of the small diameter hole 11 a of the through hole 11, and the front end side of the main shaft 6 of the through hole 13. A communication member 16 that is urged in the distal direction of the main shaft 6 by a spring member 15 exemplified as an urging member is fitted so as to be movable in the axial direction. The communication member 16 is prevented from coming out in the distal direction by a fixing member 17 fixed to the front end surface of the main shaft 6. The communication member 16 is urged by the spring member 15 toward the front end of the main shaft 6, and the front end surface of the communication member 16 is pressed against the rear surface of the flange portion of the tool holder 5. 13 is connected to the tool holder 5 from the main shaft 6 without leaking the coolant to the outside.
[0013]
The draw bar 4 is inserted into the through hole 11 of the main shaft 6 so as to be slidable in the axial direction. The draw bar 4 has a contact portion 4b with which a biasing means 21 to be described later contacts, and a large-diameter portion having a larger diameter than the contact portion 4b. 4c is formed. A holding portion 18 that clamps the pull stud 5b at the rear end portion of the tool holder by the rearward movement of the draw bar 4 in the axial direction is screwed to the screw portion. The holding portion 18 is provided with a T-shaped through hole 19 that opens in the radial direction. Communicate. As shown in FIGS. 1 to 3, the through hole 20 formed in the draw bar 4 is formed by connecting holes 20 a, 20 b, and 20 c having different diameters. A large number of disc springs 21 exemplified as urging means are stacked between the front end surface of the abutting portion 4 b of the draw bar 4 and the end surface of the through hole 11, and the draw bar 4 is moved by the spring force of the disc spring 21. When biased rearward in the axial direction (clamping direction), the tool holder 5 is clamped to the main shaft 6 by the draw bar 4, and the radial hole portion 19 c of the through hole 19 communicates with the through hole 14. Since the main shaft 6 and the through holes 13 and 20 of the draw bar 4 communicate with each other, a coolant supply path R is formed in the main shaft 6 and the draw bar 4.
[0014]
A holding state releasing mechanism 7 is provided at the rear end of the main shaft 6. The holding state release mechanism 7 allows a pin member 22 penetrating through the through hole 20 of the draw bar 4 and projecting outward from the outer peripheral surface of the main shaft 6 to slide in the front-rear direction along the outer peripheral surface of the main shaft 6. The draw bar 4 is moved via the pin member 22 by engaging with the attached moving member 23 and moving the moving member 23 forward in the axial direction by a swing arm 24 swinged forward by a driving device (not shown). It is configured to push forward in the axial direction. Further, as shown in FIG. 4, the draw bar 4 is provided with a large diameter portion 4 d larger than the shaft diameter of the pin member 22, so that the pin member 22 is fitted so as to penetrate the through hole 20 of the draw bar 4. Even so, the coolant supplied from the coolant supply means 3 can be passed in the direction of the tool holder 5. After the tool holder 5 is replaced, the tool holder 5 is clamped to the main shaft 6 by the draw bar 4 by the spring force of the disc spring 21, and the pin member 22 and the moving member 23 are pushed back to the positions shown in FIG.
[0015]
Next, a spindle driving motor 2 is installed behind the spindle 6. The main shaft driving motor shaft 2a is a hollow shaft, and a coolant supply means 3 is connected to the rear end portion of the hollow shaft 2a, and the main shaft 6 is connected to the front end portion of the hollow shaft 2a via a connecting member 25. . The connecting member 26 is fixed inside the front end portion of the hollow shaft 2a. Even if the draw bar 4 is moved forward in the axial direction by the holding state releasing mechanism 7, the leading end side of the connecting member 26 is the through hole 20 of the draw bar 4. It is designed not to be removed from the inside. Therefore, in the spindle device 1, the coolant supplied from the coolant supply means 3 passes through the hollow shaft 2 a of the spindle driving motor 2 in a state where the tool holder 5 is clamped to the spindle 6 by the draw bar 4. After passing through the coolant supply path R provided in the main shaft 6 and the draw bar 4 via 26, the tool holder 5 is supplied.
[0016]
As shown in FIG. 3, the counteracting force generating mechanism 30 pulls the draw bar 4 rearward in the axial direction and pushes the draw bar 4 forward in the axial direction and the disc spring 21 that clamps the tool holder 5 to the front end of the main shaft 6. The holding state releasing mechanism 7 for releasing the holding state of the tool holder 5 is provided between the pin member 22 and the pin member 22. The counteracting force generating mechanism 30 includes seal members on the outside of the large diameter portion 4c provided in the draw bar 4 so as to slide inside the large diameter hole 12 opened to the rear of the main shaft 6 and on the inner side of the through hole 11 of the main shaft 6. The cylinder chamber 32 is formed between the front end surface of the large-diameter portion 4c and the front end surface of the large-diameter hole 12, and the O-ring 31 illustrated as an example is provided in the cylinder chamber 32 from the coolant supply path R to the tool holder 5. The communication path 33 provided in the draw bar 4 is connected to supply a part of the supplied coolant.
[0017]
When a part of the coolant supplied from the coolant supply means 3 to the tool holder 5 is supplied to the cylinder chamber 32, the draw bar 4 is attached to the rear side in the axial direction with respect to the main shaft 6 rotatably supported by the main shaft head 8. Has come to be. The pressure receiving area of the cylinder chamber 32 depends on the pressure of the coolant passing through the coolant supply path R (in this case, the front side wall surface 19a and the tool holder 5 in which the flow changes rapidly in front of each part in the coolant supply path R). The unclamping direction force on the draw bar 4 generated by the communicating member 16 that pushes out to the pin member 22, the pin member 22 that obstructs the flow, and the step portion when the through hole 20b narrows to the through hole 20a), It is set so as to generate a clamping direction force that is just large enough to cancel.
[0018]
Accordingly, when the coolant is supplied from the coolant supply path R to the tool holder 5, the coolant pressure causes the front side wall surface 19 a of the coolant supply path R, the front end surface of the through hole 20 b of the draw bar 4, and the pin member 22 of the holding state release mechanism 7. Furthermore, a force that pushes forward in the axial direction generated with respect to the draw bar 4 by acting on the communication member 16 (force in the unclamping direction of the tool holder) is generated. Even if the coolant is supplied from the coolant supply means 3 to the tool holder 5 even if the coolant is supplied from the coolant supply means 3 to the tool holder 5, the tool bar is pressed by the spring force of the disc spring 21. It becomes possible to maintain the state which clamped 5 reliably.
[0019]
【The invention's effect】
As described above, according to the present invention, the coolant supplied from the coolant supply means to the tool holder is further moved to the spindle rear side than the biasing means for pulling the draw bar axially rearward into the spindle device and clamping the tool holder to the spindle front end. By providing a counteracting force generation mechanism that can supply a part of the force, a force in the direction of canceling out the unclamping direction force of the tool holder generated by the fluid pressure of the coolant is generated, so the drawbar securely clamps the toolholder In this state, coolant can be supplied to the tool holder. Further, since the cylinder structure utilizing the fluid pressure of the coolant is used for canceling, it is possible to simplify the configuration without requiring a driving source for generating a canceling force.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a spindle device of the present invention.
FIG. 2 is an enlarged view of a portion A in FIG.
FIG. 3 is an enlarged view of a part B in FIG. 1;
4 is a cross-sectional view taken along the line IV-IV in FIG. 3;
5 is a cross-sectional view taken along line VV in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main shaft apparatus 2 Main shaft drive motor 2a Hollow shaft 3 Coolant supply means 4 Draw bar 4b Contact part 4c Large diameter part 5 Tool holder 6 Main shaft 7 Holding state cancellation | release mechanism 12 Large diameter hole 19a Front side wall surface 21 Disc spring 30 Generation | occurrence | production of counteracting force Mechanism 31 O-ring 32 Cylinder chamber 33 Communication path

Claims (4)

  The main shaft drive motor shaft is a hollow shaft, a coolant supply means is connected to the rear end portion of the hollow shaft, a main shaft having a draw bar is connected to the front end portion, and the draw bar is drawn back in the axial direction to the main shaft. And a biasing means for clamping the tool holder to the front end of the spindle, and a spindle device for supplying coolant to the tool holder through a coolant supply path provided in the spindle and the drawbar through the hollow shaft from the coolant supply means. A pin member is fitted so as to penetrate the coolant supply path, and a holding state release mechanism is provided to release the holding state of the tool holder by pushing the draw bar forward in the axial direction via the pin member, and an urging means For the drawbar that is pulled back in the axial direction by the coolant supply path and the pin member of the holding state release mechanism That the unclamping direction force to the tool holder caused by the liquid pressure of the coolant, the spindle device characterized by comprising a bucking force generating mechanism that causes the force to cancel out by the liquid pressure of the coolant. The bucking force generating mechanism, draws drawbar axially rearward, the spindle apparatus according to claim 1, characterized in that installed in the spindle rear side of the biasing means for clamping the tool holder in the spindle end face. The canceling force generation mechanism includes a biasing means that pulls the draw bar rearward in the axial direction and clamps the tool holder at the front end of the spindle, and a holding state release that releases the tool holder holding state by pushing the draw bar forward in the axial direction. 2. The spindle device according to claim 1 , wherein the spindle device is disposed between the pin member of the mechanism. A large-diameter portion larger in diameter than the abutting portion with which the biasing member abuts is provided at the rear of the draw bar so as to slide inside the large-diameter hole opened to the rear of the main shaft. A seal member is provided on the inner side of the main shaft on which the cylinder slides, and a cylinder chamber is formed between the front end surface of the large diameter portion and the end surface of the large diameter hole, and the cylinder chamber is supplied to the tool holder from the coolant supply path. The main shaft device according to any one of claims 1 to 3, wherein a canceling force generating mechanism is configured by communicating the communication passage so as to supply a part of the coolant.

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