JP2000094255A - Main spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly draw out a tool biting into a main spindle by providing a pneumatic drive device capable of abutting on a draw bar shaft to shock it in addition to a hydraulic drive device capable of moving the draw bar shaft toward an front end of the main spindle against an energizing force of a energizing means. SOLUTION: When a tool bites into a main spindle due to a reverse cutting operation or the like, a solenoid valve 24 for a second piston 21 is released if supply of an air pressure is normal. Thereby, air is fed into a cylinder chamber 21b of the second piston 21 at the same pressure as a first piston 11. Then, the second piston 21 is moved toward a front end of the main spindle to strike a backward flange part 9c of a hammer shaft 9 so that a draw bar shaft 7 connecting with the hammer shaft 9 receives the shock force. Thereby, the biting of the tool can be released. When the biting is released, a signal is outputted from a limit switch 26 so that the tool is drawn out, and tool-changing operation for inserting the next tool is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device provided with a tool extracting mechanism, and more particularly, to a spindle device which releases a tool biting into a tapered hole of a spindle and allows automatic tool change by an ATC device. About.

[0002]

2. Description of the Related Art In a conventional machine tool such as a machining center, an operation of removing a tool from a main shaft is performed by pushing an end face of a drawbar shaft connected to a tool pulling pin by a fluid cylinder device, thereby pulling a tool. A machine tool in which a stud bolt end face is pushed in the direction of a tool and the tool can be removed from the tapered hole has become common. Also, when performing heavy cutting or when the taper surface of the tool is strong, the tool may bite into the main shaft and cannot be removed with only the thrust given by the fluid cylinder device. There is a machine tool that pushes a tool by applying an impact to a pull stud bolt end face of a tool by a hammer assist device using a spring.

[0003]

However, only when the operation of removing the liquid cylinder device is insufficient, the auxiliary device is not operated when the timing of activating the auxiliary device by the spring or while the tool changing arm is holding the tool. It is difficult to adjust the timing, and there is only one kind of spring attached to the back of the liquid cylinder device, so if the content of the cutting work is changed and an impact exceeding a certain thrust is required, it is necessary to replace it with another spring each time There is.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present inventor has provided a spindle device capable of reliably extracting a tool biting on a spindle by applying an impact to a drawbar shaft by adding a simple mechanism. With the goal. The invention according to claim 1 of the present invention provides a spindle having a tool inserted into a tip thereof,
A drawbar shaft whose leading end engages with the tool and is movable in the axial direction of the spindle, an urging means for urging the drawbar shaft toward the rear end of the spindle, and a tool that pushes the drawbar shaft toward the front end of the spindle by fluid pressure to eject the tool. A first fluid pressure drive device withdrawn from the main shaft, wherein the drawbar shaft is separated from the first fluid pressure drive device capable of moving the drawbar shaft to the main shaft tip side against the urging force of the urging means. A second fluid pressure driving device capable of abutting so as to apply an impact; and a detection member for detecting a pushing state of the drawbar shaft, wherein the first fluid pressure driving member is instructed by the detection member that has detected the biting of the tool. This is a spindle device that applies an impact to the drawbar shaft pressed by the second hydraulic pressure driving member and strikes the drawbar shaft toward the spindle front end side. Here, the detection member for detecting the push-out state of the drawbar shaft includes a pressure switch for measuring that the drawbar shaft does not move and detects that the drawbar shaft has reached a predetermined pressure because the drawbar shaft does not move. A variable timer for measuring that a predetermined time has elapsed since the pressure is applied to the pressure driving member and started, and a limit switch for detecting a position or a distance at which the draw bar shaft or its associated member or tool has moved in the axial direction. is there. In addition, a proximity switch or a photoelectric tube may be used as a signal generator in addition to the limit switch.

According to a second aspect of the present invention, a fluid passage is provided in the second fluid pressure driving member, the draw bar shaft, and the tool, and the second fluid pressure driving member does not push out the draw bar shaft. This is a spindle device in which a pressure drive member is brought into contact with a drawbar shaft to communicate a fluid passage to reach a tool. Conventionally, in order to discharge fluid from the tool while holding the fluid passage while the fluid discharge tool for removing chips is inserted into the main shaft, separately from the fluid pressure drive member that pushes the drawbar shaft to the main shaft tip side Therefore, it is necessary to provide a dedicated fluid pressure driving member capable of holding a tool. However, by simply attaching the fluid pressure adjusting member to the second fluid pressure driving member for releasing the bite of the tool, and making the fluid passage abut against the draw bar shaft with a weak thrust that does not push out, the fluid passage is driven by the second fluid pressure driving member. Since it is possible to discharge fluid from the tool while holding from the member to the drawbar shaft and the tool,
The entire apparatus can be miniaturized, and the maintenance work can be easily and efficiently processed by using common members.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a spindle machine according to the present invention will be described in detail with reference to a horizontal machine tool. FIG. 1 is an explanatory view showing a cross section of a spindle head and a pneumatic system provided on the spindle head, and shows a state in which a tool is clamped on the spindle. The spindle head 1 is configured by assembling a removal portion 1b behind a spindle portion 1a provided inside a housing 2.

The main shaft portion 1a is rotatably supported by a suitably arranged bearing 4a, into which a tool 3 is inserted at the tip, and is driven by a well-known motor (not shown). At the tip of the main shaft 4, there is provided a collet 6 for clamping the pull stud bolt 3a of the tool 3, and a draw bar shaft 7 is provided movably in the axial direction via a tool lifting pin 6a to open and close the collet 6. I have.
The rear end of the drawbar shaft 7 is urged rearward by the disc spring 8 to the rear of the main shaft, and the collet 6 is closed by the retracted tool lifting pin 6a to clamp the tool 3.

A hammer shaft 9 for pushing out the rear end face of the draw bar shaft 7 toward the front end of the main shaft and extracting the tool 3 is attached to the extraction portion 1b so as to be movable in the axial direction of the main shaft 4.
In the normal state, a gap S is formed between the hammer shaft 9 and the drawbar shaft 7 because the compression spring 9a urges the main shaft rearward. The first piston 11 and the second piston 21 inserted around the hammer shaft 9 have a sealing member appropriately mounted on the contact surface with the hammer shaft 9, and the main shafts of the cylinder chambers in which the pistons 11 and 21 slide. A pneumatic passage 1 for tool removal is provided on the rear end side and the spindle tip side.
3, 23 and pneumatic passages 13a, 23a for returning
Is connected. The pneumatic passages 13, 23, 13a,
Since the solenoid valves 23 and 24a are provided with solenoid valves 14 and 24 for switching air suction and discharge, respectively, the first piston 11 and the second piston 21 can operate independently to slide the hammer shaft 9. it can. The pushing state of the hammer shaft 9 is determined by checking a predetermined position of the hammer shaft 9 by a limit switch 26 attached to the rear end of the hammer shaft, and when the limit switch 26 is not ON, it is turned ON by a control circuit (not shown). ,
The second piston 21 described later is started.

The first piston 11 is formed by integrating three front pistons 111, a middle piston 112 and a rear piston 113 in order to oppose the urging force of the disc spring 8, and the front piston 111 is moved forward by a cylindrical portion 111a. Is extended, and the disc spring 8 of the drawbar shaft 7 can be directly pushed. The front end of the middle piston 112 engages with the front flange portion 9b of the hammer shaft 9 when the front end of the middle piston 112 is pushed out and slid, and the hammer shaft 9
Can be moved to the front end of the main shaft, while being urged toward the rear end of the main shaft by a compression spring 112a fixed to the cylinder block 10. The second piston 21 is normally in contact with a compression spring 113a which is fixed to the cylinder block 10 and urges toward the rear end of the main shaft, and is pushed to the rear flange 9c of the hammer shaft 9 when pushed out toward the front end of the main shaft. The engagement causes the hammer shaft 9 to move toward the tip of the main shaft. Also,
A pneumatic pressure adjusting device 25 for switching the pressure of air supply between two levels is provided in the pneumatic passage. Since the first piston 11, the second piston 21 and the hammer shaft 9 are always held in the direction away from the drawbar shaft 7 and the rear end of the main shaft by the compression springs 112a, 21a and 9a, the fluid pressure source Even if it breaks, there is no contact with the drawbar shaft 7. Drawbar shaft 7
At the rear end, a dog 2 facing the limit switch 26
The limit switch 26 engaged with the dog 26a at the stroke end of the drawbar shaft 9 that has been mounted and moved to the front end of the main shaft transmits a tool removal signal to the control device of the machine tool.

Next, the operation of the spindle head constructed as described above will be described with reference to FIG. 4 showing a flowchart. When clamping a tool, as shown in FIG.
The drawbar shaft 7 is pushed toward the rear end of the main shaft by the urging force of the disc spring 8, and the collet 6 clamps the pull stud bolt 3a of the tool 3. Further, the hammer shaft 9 of the extracting portion 1b is also pushed toward the rear end of the main shaft by the compression spring 9a, so that a gap S is provided between the drawbar shaft 7 and the hammer shaft 9.
The end surface of the hammer shaft 9 is prevented from being worn by the draw bar shaft 7 whose main shaft 4 is rotated by cutting.
Then, a tool exchange command is issued (step 1, hereinafter S
Shown as 1. When releasing the clamp, first, when the tool is lightly fastened and there is no biting to the main shaft, the air compressor is started by the release command and the second piston 21 is released.
The solenoid valve 14 of the first piston 11 is opened alone (S2) while the solenoid valve 24 connected to the cylinder chamber 111b, 1 is closed.
The air supplied to 12b and 113b causes the three first pistons 11 to move toward the tip of the main shaft against the compression springs 112a.
(S2). The front end of the middle piston 112 which is pushed out and slides on the outer periphery of the hammer shaft 9 engages with the front flange portion 9b to move the hammer shaft 9 toward the front end of the main shaft, and the cylindrical portion 111a of the front piston 111 is directly connected to the drawbar. The shaft 7 is pushed out against the disc spring 8. At this time, if there is no bite, the hammer shaft 9 is moved by the operation of the first piston 11 and the pull stud bolt 3 of the tool 3 is moved.
The collet 6 which has clamped a is released to release the tool 3 from the spindle 4 and a signal is transmitted from the limit switch 26 (S4, YES), the exchange arm of the ATC device is started and the tool is pulled out. Then, the process proceeds to a tool changing operation for inserting the tool (S13). On the other hand, when the tool bites into the spindle due to heavy cutting or the like, regardless of the opening operation of the collet 6 due to the operation of the first piston 11, the limit switch 26 does not transmit a signal (S4, NO) It is determined that the tool release operation has not been completed, and the ATC device is made to stand by without starting the exchange arm or the like, and the pressure switch 15 detects a pressure difference before and after the pressure is applied, and the difference is reduced to a predetermined pressure value. To detect whether air pressure is supplied normally without exceeding (S
5). If the supply of air pressure is abnormal, an alarm is displayed and stopped (S14). If the supply of air pressure is normal, the solenoid valve 24 of the second piston 21 is opened (S6). As a result, air is supplied to the cylinder chamber 21b of the second piston 21 at the same pressure as that of the first piston 21, and the second piston 21 moves toward the tip end of the main shaft to the position shown by the dashed line in FIG. The rear flange 9c is hit (S7), and the impact is applied to the drawbar shaft 7 connected to the hammer shaft 9. Accordingly, when the bite is released, a signal is transmitted from the limit switch 26 (S8,
YES), the process shifts to a tool changing operation of removing the tool and inserting the next tool (S13). On the other hand, if the bite has not been eliminated, the solenoid valve 24 of the second piston 21 is closed (S8) to apply the impact again, and after the second piston 21 is pulled back (S11), the process returns to step 6. . If the bite does not disappear even after several impacts, the number of times is added (S12) to display an alarm (S14), and it is detected whether the number of times reaches a predetermined number (S9).

Although the ON operation has been confirmed twice in S4 and S8 in FIG. 4 using the limit switch as a detecting member, it is assumed that a predetermined time has elapsed since the first piston was applied with pressure and started. It may be a variable timer for measuring. More specifically, the predetermined time is set to a normal time until the tool is released by pushing out the drawbar shaft, for example, about 2 seconds. If biting of the tool occurs, the solenoid valve of the second piston 21 is terminated by terminating the variable timer. 24 is set to open. As a result, air is supplied to the cylinder chamber 21b of the second piston 21 at the same pressure as that of the first piston 21, and the second piston 21 moves toward the front end of the main shaft and strikes the rear flange portion 9c of the hammer shaft 9, thereby causing the hammer shaft 9 to move. As a result of an impact on the drawbar shaft 7 connected to the main shaft 9, the tool 3 biting the main shaft 4 can be removed. On the other hand, if there is no biting of the tool, a release command is input only once by the limit switch 26 before the end of the variable timer,
Change the setting so that the end signal of the variable timer becomes invalid.

Next, a description will be given of a spindle device configured as described above and performing air blowing while a tool is inserted into the spindle. The hammer shaft 9 shown in FIG. 1 is provided with a compression spring 9a that urges the drawbar shaft 7 in a direction away from the drawbar shaft 7 or toward the rear end of the main shaft to provide a gap S between the hammer shaft 9 and the drawbar shaft 7. . On the other hand, the air pressure adjusting device 25 attached to the air pressure passage 23 of the second piston 21 can adjust the supply pressure of air in at least two or more stages. Since the hammer shaft 9 moves to the main shaft tip side as described above, it can move to the stroke end as shown by the two-dot chain line, and the tool 3 that bites into the main shaft 4 by the impact when the end surface of the hammer shaft 9 is pressed is released. Can be canceled. On the other hand, in the low pressure stage, the front end of the second piston 21 pushed out by the air engages with the rear flange 9b of the hammer shaft 9, and the compression spring 9b
The hammer shaft 9 is pushed out toward the tip of the main shaft against the urging force of the above, the gap S disappears, and the drawbar shaft 7 comes into contact with the hammer shaft 9 at the end face. In this state, the drawbar shaft 7 is not pushed out against the hammer shaft 9 and the first piston 11 against the disc spring 8, so that the tool is detached or loosened while the tool 3 remains inserted into the main shaft 4. This is different from the state shown in FIG. And pneumatic passage 3
1 is disposed so as to extend from the solenoid valve 32, the suction port 33, and the hammer shaft pneumatic passage 34 to the air blow tool 3 of the main shaft through the drawbar shaft pneumatic passage 35 which is continuously provided without the gap S. Have been. That is, the low pressure stage of the air pressure adjusting device 25 is larger than the urging force of the compression spring 9b,
It is set to be smaller than or similar to that of the disc spring 8.
As described above, conventionally, it was necessary to provide a dedicated piston for air blowing, but by attaching the air pressure adjusting member to the second piston for releasing the biting of the tool, the urging force of the disc spring was improved. By simply pushing out the hammer shaft with the same weak thrust as above, the air blow can be performed while holding the pneumatic passage. Maintenance work can now be easily and efficiently processed.

Note that the present invention is not limited to the above embodiment, and the pneumatic circuit may be changed to a hydraulic circuit, a hammer shaft may be provided for each of the first piston and the second piston, or the hammer shaft may be provided for the first piston. Appropriately changing the shape and configuration of each part without departing from the gist of the present invention, such as applying it to a piston rod of the first piston and the second piston, or applying it to a machine tool equipped with a vertical machining center or other various spindle devices. It can also be embodied.

[0014]

As described above in detail, according to the spindle device of the first aspect, the tool biting the spindle is reliably removed by the mechanism of the simple second piston interlocking with the piston for extracting the tool. It has an excellent effect that it can be performed. Further, according to the spindle device of the second aspect, a dedicated piston for air blow, which is conventionally required, is not provided, so that not only the entire device can be reduced in size, but also the second device for releasing the biting of the tool. By attaching the air pressure adjusting member to the piston, the air blow can be performed only by pushing out the hammer shaft with a weak thrust, so that the maintenance work can be easily and efficiently processed by the common use of the members.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a cross section of a spindle head showing an embodiment of the present invention, and a pneumatic system provided on the spindle head.

FIG. 2 is an explanatory view showing a state in which a tool bites into a main shaft and is released by a second piston.

FIG. 3 is an explanatory diagram showing a state in which air is blown while a tool is inserted into a spindle.

FIG. 4 is a flowchart.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 spindle head 1a spindle part 1b extraction part 2 housing 3 tool 3a pull stud bolt 4 spindle 4a bearing 5 motor 6 collet 6a tool lifting pin 7 drawbar shaft 8 disc spring 9 hammer shaft 9a compression spring 9b front flange 9c rear flange 10 Cylinder block 11 First piston 111 Front piston 111a Cylindrical part 111b Cylinder chamber 112 Medium piston 112a Compression spring 112b Cylinder chamber 113 Rear piston 113b Cylinder chamber 12 Cylinder chamber 13 Pneumatic passage 14 Solenoid valve 15 Pressure switch 21 Second piston 21a Compression spring 21b Cylinder chamber 23 Pneumatic passage 24 Solenoid valve 25 Pneumatic pressure regulator 26 Limit switch 26a Dog 31 Pneumatic passage 32 Solenoid valve 33 Suction port 34 Hammer shaft pneumatic Road 35 Drawbar shaft pneumatic path

Claims (2)

[Claims] 1. A main shaft on which a tool is inserted at a front end, a drawbar shaft whose front end engages with the tool and is movable in the axial direction of the main shaft, and an urging means for urging the drawbar shaft rearward of the main shaft. A first fluid pressure driving device for extruding the tool from the main shaft by pushing the draw bar shaft toward the main shaft front end by fluid pressure, wherein the draw bar shaft is moved toward the main shaft front end against the urging force of the urging means. In addition to the possible first fluid pressure drive device, a second fluid pressure drive device which can be brought into contact with the drawbar shaft so as to apply an impact, and a detection member for detecting a pushing state of the drawbar shaft are provided, and a tool bite is provided. A spindle device wherein a drawbar shaft pressed by a first fluid pressure drive member is impacted by a second fluid pressure drive member to strike the tip end side of the spindle in accordance with an instruction from a detection member that has detected the attachment. 2. A fluid passage is provided in the second fluid pressure driving member, the draw bar shaft and the tool, and the second fluid pressure driving member abuts on the draw bar shaft in a state where the first fluid pressure driving member does not push out the draw bar shaft. The spindle device according to claim 1, wherein the fluid passage communicates with the tool to reach the tool.