JP3595106B2 - Spindle head of machine tool - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a spindle head of a machine tool provided with a tool extracting mechanism.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a technique has been known in which a tool is pushed out of a spindle head of a machining center by a piston and extracted. For example, a spindle head shown in FIG. 7 has a spindle 4 having a tapered hole 4a at the tip of which a tool 3 is inserted, a drawbar 5 movably inserted in the spindle 4 in the axial direction, and a fluid pressure drive. And the piston 6 pushes the drawbar 5 toward the tip end of the main shaft 4 to extract the tool 3 from the tapered hole 4a.
[0003]
In addition, a technique for removing a tool by applying an impact to a drawbar is also known. For example, in a tool extracting device disclosed in Japanese Patent Application Laid-Open No. 3-149150, when a tool exchange arm grips a tool, a cam provided on the tool exchange device applies an impact to a drawbar via a plurality of interlocking members. The tool is configured to hit and push the tool with the tip of the drawbar.
[0004]
[Problems to be solved by the invention]
However, according to the former spindle head, when the tool 3 bites into the tapered hole 4a due to pressure bonding during heavy cutting or adhesion of the cutting fluid, the pushing force of the piston 6 is insufficient, and it becomes difficult to remove the tool 3. There was something. On the other hand, the latter extraction device has an advantage that the tool can be reliably extracted by the impact force, but has a problem that a mechanism for synchronizing the exchange arm and the drawbar is complicated.
[0005]
Therefore, an object of the present invention is to provide a spindle head of a machine tool capable of reliably extracting a tool biting on a spindle by a simple mechanism linked to a piston for extracting a tool.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a main spindle in which a tool is inserted at a tip, a drawbar movable in an axial direction of the main spindle, and a tool that pushes the drawbar to a tip end side of the spindle inside a housing. At the spindle head of a machine tool equipped with a piston that is removed from the spindle, the piston is double-acting , the engagement shaft is extended to the piston, the frame is fixed to the housing, and the hammer base is attached to the frame in the axial direction with respect to the piston. Provided so as to be relatively movable, fix the hammer to the hammer base, interpose a spring member for urging the hammer toward the main shaft tip side between the frame and the hammer base, and provide the frame with a locking member that engages with the hammer base. provided, the abutment member which faces the hammer from the spindle tip end side in the engaging shaft, the actuating member which engages the locking member is provided, when the piston is moved to the spindle base end side during tool clamping, The hammer base is moved against the biasing force of the spring member via the coupling shaft and the abutment member, while engaged in place the hammer base by the locking member, at the time of tool unclamping, the spindle tip end side of the piston The operating member releases the urging force of the spring member by disengaging the locking member from the hammer base at the substantially moving end of the spring member.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a spindle head of a vertical machining center will be described with reference to the drawings. As shown in FIG. 1, the spindle head is configured by assembling a removal assisting device 2 on an upper end of a housing 1. As in the prior art, a main shaft 4 (see FIG. 7) into which a tool 3 is inserted at the front end, a drawbar 5 movable in the axial direction of the main shaft 4, and a drawbar 5 pushed out toward the front end of the main shaft, as in the prior art. A piston 6 for extracting the tool 3 by pressing and a cylinder 7 for accommodating a pressure receiving portion 6a of the piston 6 are provided. An engagement shaft 8 that engages with the extraction assisting device 2 is provided on the piston 6 so as to extend upward from the housing 1.
[0008]
As shown in FIGS. 1, 2, and 3, a frame 10 of the extraction assisting device 2 is fixed to an upper surface of the housing 1. A hammer base 11 is connected to the long hole 10a of the frame 10 so as to be relatively movable in the axial direction with respect to the piston 6, and three hammers 12 are formed on the lower surface of the hammer base 11 at an angle of 90 ° around the piston 6. Is fixed. Further, two rods 13 are erected on the upper surface of the hammer base 11, and the upper ends thereof are inserted into the guide holes 10 b of the frame 10. A coil spring 14 as a spring member is interposed between the frame 10 and the hammer base 11, and the hammer 12 is urged downward by the urging force of the main shaft, that is, downward.
[0009]
On the other hand, an abutment plate 16 facing the hammer 12 from below and a plate 17 facing the hammer base 11 from above are connected to the engaging shaft 8 by a nut 19 via a collar 18. At both ends of the plate 17, operating claws 20 project downward, and a pair of side plates 21 joined to the inner surface of the operating claws 20 are fixed to the frame 10. An L-shaped block 22 is fixed to the side plate 21, and a slider 23 is slidably supported on the block 22 in a direction perpendicular to the axis of the main shaft, and is pressed against the operating claw 20 by a spring 24.
[0010]
The slider 23 has a pair of locking claws 23a that engage with the hammer base 11, and as shown in FIG. 4, the hammer 12 is brought into a fixed position against the urging force of the coil spring 14 during the lowering of the piston 6. It constitutes a locking member for locking. The operating claw 20 has a tapered surface 20a that engages with the slider 23. As shown in FIG. 5, the locking claw 23a is disengaged from the hammer base 11 at a substantially lower end of the piston 6, and the urging force of the coil spring 14 is applied. The actuating member for releasing is constituted. As shown in FIG. 6, the hammer base 11 is formed with an inclined surface 11a that pushes the locking claw 23a outward when the piston 6 is raised.
[0011]
Next, the operation of the spindle head configured as described above will be described. At the time of tool clamping, as shown in FIGS. 1 and 2, the piston 6 is held at the rising end, the hammer base 11 of the extraction assisting device 2 is locked by the locking claw 23a, and the coil spring 14 is compressed. At the time of tool unclamping, as shown in FIG. 4, the engagement shaft 8, the abutment plate 16, the plate 17, and the operation claw 20 descend integrally with the piston 6, and the slider 23 is gradually pushed outward by the tapered surface 20a. However, the locking claw 23a still engages with the hammer base 11 to hold the coil spring 14 in a compressed state.
[0012]
As shown in FIG. 5, when the piston 6 reaches the lower end or the position immediately before the lower end, the locking claw 23a is disengaged from the hammer base 11 by the action of the tapered surface 20a, and the urging force of the coil spring 14 is released. As a result, the hammer base 11 instantaneously descends, and the hammer 12 collides with the contact plate 16 and gives an impact to the drawbar 5 via the engagement shaft 8 and the piston 6. Therefore, even when the tool 3 bites into the tapered hole 4a, the drawbar 5 can reliably remove the tool 3 by the pushing force of the piston 6 and the impact force of the hammer 12.
[0013]
After the tool change, as shown in FIG. 6, the contact plate 16 and the operating claw 20 are raised, the hammer base 11 is pushed up by the contact plate 16, and the locking claw 23a is once pushed out by the inclined surface 11a. After that, it protrudes inward by the urging force of the spring 24, and the removal assisting device 2 returns to the tool clamp mode shown in FIG. Therefore, according to this spindle head, the hammer base 11, the operating claw 20, and the locking claw 23a can be driven in conjunction with the piston 6, respectively, and there is no need to provide a dedicated driving source in the extraction assisting device 2, which is simple. The mechanism can reliably pull out the tool 3.
[0014]
Note that the present invention is not limited to the above-described embodiment, and may be applied to a horizontal machining center or a spindle head of various other machine tools, and may appropriately change the shape and configuration of each part without departing from the spirit of the present invention. It can also be embodied.
[0015]
【The invention's effect】
As described above in detail, according to the spindle head of the present invention, an excellent effect that a tool biting the spindle can be reliably removed by a simple mechanism linked to a tool removal piston.
[Brief description of the drawings]
FIG. 1 is a sectional view of an upper end portion of a spindle head showing one embodiment of the present invention.
FIG. 2 is a sectional view taken along the line AA of FIG. 1, showing the spindle head extraction assist device.
FIG. 3 is a sectional view taken along line BB of FIG. 2;
FIG. 4 is a cross-sectional view showing an operation mode of the extraction assisting device when the piston descends.
FIG. 5 is a cross-sectional view showing an operation mode of the extraction assist device at the time of tool unclamping.
FIG. 6 is a cross-sectional view showing an operation mode of the extraction assisting device when the piston is raised.
FIG. 7 is a sectional view showing a conventional spindle head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Extraction assistance device, 3 ... Tool, 4 ... Main shaft, 5 ... Drawbar, 6 ... Piston, 7 ... Cylinder, 8 ... Engagement shaft, 10 ... Frame, 11 ··· Hammer base, 12 · hammer, 14 ·· coil spring, 16 ··· contact plate, 20 ·· operating claw, 23 ··· slider, 23a ·· locking claw, 24 ··· spring.

Claims (1)

Inside the housing, a spindle head of a machine tool including a spindle into which a tool is inserted at the tip, a drawbar movable in the axial direction of the spindle, and a piston for pushing the drawbar to the tip of the spindle and removing the tool from the spindle. At
The piston is double-acting , the engagement shaft is extended to the piston, the frame is fixed to the housing, the hammer base is provided on the frame so as to be relatively movable in the axial direction with respect to the piston, and the hammer is fixed to the hammer base. A spring member for urging the hammer toward the spindle front end is interposed between the hammer base and the hammer base, and a locking member for engaging the hammer base is provided on the frame, and the engaging shaft is opposed to the hammer from the spindle front end side. Providing a contact member and an operating member that engages with the locking member,
When the piston moves toward the main shaft base end side during tool clamping, the hammer base is moved against the urging force of the spring member via the engaging shaft and the abutting member, and the hammer base is fixed in position by the locking member. A machine tool characterized in that, when the tool is unclamped , the actuating member disengages the locking member from the hammer base and releases the biasing force of the spring member at a substantially moving end of the piston at the tip end side of the tool when the tool is unclamped. Spindle head.

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