JP2857102B2 - Spindle device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device for a machine tool, and more particularly to an improvement in a tool mounting portion thereof.

[0002]

2. Description of the Related Art For example, a machine tool such as a machining center (MC) provided with an automatic tool changer (ATC) has a tapered hole 2 for mounting a tool at the tip of a spindle shaft 1 as shown in FIG. A predetermined tool is mounted by fitting a taper shank portion 4 of a tool holder 3 into the tapered hole 2. In this conventional spindle device, the tool holder 3 is held on the spindle shaft 1 only at the tapered shank portion 4, and the rigidity cannot be said to be very high, and the degree of contact between the tapered hole 2 and the tapered shank portion 4 is also reduced. However, it is difficult to perform heavy cutting because it may not be a correct hit, and it is difficult to obtain a good cut surface in the case of finish cutting.

Recently, in order to solve such a problem, FIG.
A new type of spindle device has been proposed as shown in FIG. This means that the tool holder 3 is held between the tapered shank portion 4 and the tapered hole 2 and between the end face 3a of the tool holder 3 and the end face 1a of the spindle 1 on both sides.

[0004] However, in the case of such a spindle shaft of the two-plane constraint type, it is very difficult as a practical matter to make the tapered surface and the shaft end surface crossing the tapered surface come into contact at the same time. In addition, in that case, in order to ensure an effective tool holding force, the gap between the end face 3a of the tool holder 3 and the end face 1a of the spindle shaft 1 is further increased in a state where the tapered hole 2 and the tapered shank portion 4 are in contact with each other. It is necessary to apply a preload with a negative value of δ, and it is necessary to control the contact between the tapers within an extremely strict range of approximately 2 μm. However, since the tool holders 3 are changed every time the type of tool is different, it is necessary to use a large number of tool holders 3, and it is difficult to strictly control the clearance between the spindle 3 and all the tool holders 3. Due to the considerable difficulty, another problem arises that the interchangeability of the tool holder 3 is not good.

[0005] On the other hand, the applicant of the present invention has previously disclosed in
No. 178607 proposes a new spindle device. As shown in FIG. 9, a small-diameter portion 30 and a large-diameter portion 31 are formed on the outer surface of a spindle shaft 1 having a tapered hole 2 for tool attachment at the shaft end, and a fluid penetrating to the outside is provided on the outer surface. Fixing sleeve 33 provided with passage 34
Are fitted with the interference. On the other hand, a flange 3f having a larger diameter than the taper shank 4 is provided at the base of the taper shank 4 of the tool holder 3. Then, by applying a fluid pressure to the fluid passage 34 of the fixing sleeve 33,
The fixing sleeve 33 is brought into contact with the flange portion 3f of the tool holder 3 fitted to the spindle shaft 1, and thereafter, the fixing sleeve 33 is fixed to the spindle shaft 1 except for the fluid pressure, and the tool holder 3 has high rigidity. It is to support. This eliminates the need to manage the gap between the end face of the tool holder and the end face of the spindle shaft, so that good interchangeability of the tool holder and high holding rigidity can be obtained.

[0006]

However, in the conventional spindle device described in the above publication, since there is no stopper in the axial direction of the fixing sleeve 33, the tool holder 3 is fitted to the tapered shank portion 4. When the fluid pressure is applied to the fluid passage 34 of the fixing sleeve 33 when the drawbar for holding the tool holder 3 at the clamp position (retracted position) by pulling the tool holder 3 at the unclamped position (forward position) is not in use. 33 comes off the spindle shaft 1.

When the tool holder 3 is detached from the spindle shaft 1 (during unclamping), the draw bar is moved forward to the unclamping position so that the tool holder 3 protrudes. Then, in order to shorten the replacement work time, the draw bar is moved forward to the unclamping position, and at the same time, the operation of driving the holder replacement arm of the ATC device for receiving the tool holder 3 to be replaced is started. However, if the drawbar advances first and comes into contact with the end of the tool holder 3 and protrudes the tool holder 3, the tool holder 3 is disengaged from the spindle shaft 1 before the holder replacement arm comes. The holder exchanging arm cannot receive the tool holder 3.

A pipe connecting portion 35 for supplying a fluid pressure p to a fluid passage 34 of the fixing sleeve 33 is provided, for example, in FIG.
(A) has a female screw 36f structure in which the male screw 36m of the connection joint is screwed, or FIG.
As shown in the above, the fitting structure with the O-ring seal 38 attached to the connection pipe 37 complicates the positioning of the connection joint and the coupling operation with the pipe connection part 35, and for example, tool exchange is performed by ATC. It becomes difficult to keep up with the exchange speed. And other unresolved issues.

Accordingly, the present invention has been made in view of such an unsolved problem in the related art, and the fixing sleeve does not drop off from the spindle shaft in a state where the tool holder is not mounted. Also, it is possible to provide a spindle device that does not need to protrude a tool holder with a draw bar at the time of unclamping, and that can automatically attach and detach a fluid pressure supply pipe at the time of tool exchange with one touch, thereby greatly reducing tool exchange time. The purpose is.

[0010]

According to a first aspect of the present invention, there is provided a spindle device having a tapered hole for mounting a tool at a shaft end and a small diameter portion having a small diameter at the shaft end side. And a tool holder having a tapered shank portion fitted into a tapered hole of the spindle shaft and a flange portion having a larger diameter than the tapered shank portion, and a small diameter of the spindle shaft. A fixing sleeve having a fluid passage that penetrates to the outside of the connecting portion between the small-diameter portion and the large-diameter portion, and a fluid pressure is applied to the fluid passage. The diameter of the fixing sleeve is increased and the shaft is advanced in the axial direction to release the fitting between the tapered hole of the spindle shaft and the tapered shank of the tool holder, and the fluid pressure is removed to reduce the diameter of the fixing sleeve. In a spindle device configured to fit the taper shank portion of the tool holder into the tapered hole of the spindle shaft to clamp the tool holder, when a fluid pressure is applied to the fluid passage at the shaft end of the spindle shaft. A drive key for restricting a forward moving distance of the fixing sleeve is disposed to face the fixing sleeve via an axial gap.

A spindle device according to a second aspect of the present invention is the spindle device according to the first aspect, wherein a pressure fluid supply device for feeding a pressure fluid to a fluid passage of the fixing sleeve and a taper hole in the spindle shaft are provided. A drawbar pressing device that presses a drawbar holding a tool holder in a holding release direction, and, when exchanging the tool holder, first turns on the pressing device of the drawbar to move the drawbar to a holding release position, and then the pressure liquid supply device And a control means for releasing the connection between the tapered hole of the spindle shaft and the tool holder held therein by turning on and projecting the tool holder with the fixing sleeve.

According to a third aspect of the present invention, in the spindle device according to the first or second aspect, a flat portion is provided at an inlet of a fluid passage of the fixing sleeve, and a tip of a fluid supply nozzle is provided. It is characterized by having a pressure liquid supply structure in which a seal member is provided, and the tip of the fluid supply nozzle is pressed against the flat portion via the seal member to connect to the fluid passage.

According to the first aspect of the present invention, the drive key attached to the shaft end of the spindle shaft functions as a stopper that regulates the moving distance of the fixing sleeve that moves forward when fluid pressure is applied to the fluid passage. That is, even if the fixing sleeve is pressurized when the tool holder is not mounted, the fixing sleeve does not fall off the spindle shaft.

Further, the control means according to the second aspect of the present invention shifts the operation timing of the draw bar pressing device and the operation timing of the pressurized liquid supply device to the fixing sleeve when the tool holder is unclamped, First, the draw bar is moved to the tool holder holding release position (at this time, the draw bar does not kick the tool holder). Thereafter, the pressure liquid supply device is turned on, and the fixing sleeve is advanced to kick the tool holder. That is, the release timing of the tool holder held in the tapered hole of the spindle shaft is freely adjusted separately from the movement of the drawbar.

In the pressure liquid supply structure according to the third aspect of the present invention, it is only necessary to press the fluid supply nozzle against the flat portion of the fixing sleeve via the seal member, and the fluid supply nozzle can be accurately positioned. Can connect.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The same or corresponding parts as those in the related art are denoted by the same reference numerals.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention. A spindle shaft 1 of a spindle device has a plurality of (four in the figure) ball bearings 6 and a single one. It is horizontally supported rotatably in a housing 8 via a roller bearing 7. The housing 8 is a cylindrical body surrounding the outer periphery of the bearings 6 and 7 and having an attachment flange 9 on an outer surface, a front lid 11 fixed to a front end surface of the outer cylinder 10 with bolts B1, and a rear cover. And a rear lid 12 fixed to the end face with bolts B2.

The outer cylinder 10 has a spiral groove E on the outer peripheral surface. When the spindle device is attached to the bore, the groove E forms a spiral passage between the groove and the inner surface of the bore. The cooling fluid flows through the spiral passage to cool the spindle device.

The front lid 11 fixes the outer races 6 a of the plurality of ball bearings 6 to the inner surface of the housing 8 via the outer spacer 13. An inner ring 6b of the ball bearing 6 is fixed to an outer peripheral surface of the spindle shaft 1 by a holding ring 15 via an inner spacer 14. On the other hand, the rear lid 12 is provided with the outer race 7 of the roller bearing 7.
a is fixed to the inner surface of the housing 8. The inner ring 7b of the roller bearing 7 is fixed to the outer peripheral surface of the spindle shaft 1 by a pulley 17 which is in contact with the inner ring pressing cover 16 via a ring-shaped inner ring pressing cover 16. The pulley 17 is attached to the outer peripheral surface of the spindle shaft 1 by interference fit, and has a fluid pressure supply port F at a rear end thereof. When the pulley 17 is attached or detached, the fluid pressure supply port F increases the diameter of the pulley 17 by applying pressure to the fitting surface, thereby facilitating attachment and detachment.

At the center of the shaft end of the spindle shaft 1 rotatably supported in this manner, a tapered hole 2 for tool attachment is formed, and a tapered hole 2 is provided from the back of the tapered hole 2 to the rear end of the spindle shaft. A through hole 18 is formed through the axis of the spindle 1, and a through hole 18 is provided with a tool attachment / detachment mechanism described below.

A taper shank 4 of a tool holder 3 for holding a tool 21 is fitted into the tapered hole 2. The tool holder 3 is provided with a flange 3f having a diameter larger than that of the taper shank portion at the base of the taper shank portion 4. A pull stud 22 having a small-diameter neck portion 22a and a large-diameter head portion 22b is provided at the top of the tapered shank portion 4 so as to fit into the through hole 18 of the spindle shaft. .

The tool attaching / detaching mechanism is arranged such that a plurality of ball collets 23 for gripping the pull studs 22 of the tool holder 3 fitted in the through holes 18 are equally spaced around the circumference so as to be retractable in the radial direction. A drive draw bar 25 for driving the sleeve 24 to move forward and backward has a held sleeve 24, and a rear end protrudes from the spindle shaft 1 through the through hole 18. The rear end of the draw bar 25 is driven to be pressed by the piston of the draw bar pressing device D. When the pressing of the draw bar 25 is released, the draw bar 25 is retracted by the disc spring 26, so that the sleeve 24 is also retracted. At this time, the ball collet 23
Is moved from the relatively large-diameter space 18a of the through hole 18 to the smaller-diameter space 18b while being pushed by the inner peripheral surface of the hole and protruding toward the inner diameter side of the sleeve 24. 22b. When the sleeve 24 is moved forward by driving the drawbar pressing device D, the ball collet 23 is moved into the large-diameter space 18 a of the through hole 18.
The sleeve 24 is retracted from the inner diameter surface 24 a of the sleeve 24. Thereby, the tool holder 3 can be extracted (see FIG. 5). This figure 5
In the state where the draw bar 25 is at the forward limit position shown in FIG. 3, a gap α is formed between the rear end surface of the head 22b of the pull stud 22 of the tool holder 3 and the inner surface 24b of the inner diameter of the sleeve 24 opposed thereto. Is to be interposed. The clearance α prevents the tool holder 3 from protruding (kick) due to the advance of the draw bar 25.

A number of disc springs 26 are mounted on the outer periphery of the draw bar 25 inside the through-hole 18, and constantly urge the draw bar 25 strongly toward the rear end. 27 is a disc spring 2
Reference numeral 6 denotes a holding ring, and 28 denotes a lock nut for fixing the holding ring 27 to the spindle shaft 1.

As shown in FIGS. 2 and 3 in an enlarged manner, a pair of drive keys 29 for positioning the tool holder 3 and the spindle shaft 1 in the rotational direction are provided at the tip of the spindle shaft 1 (on the side where the tool holder is mounted). , Bolt B3 symmetrically around the axis center
It is fixed and attached. The drive key 29 has a hexahedral shape, and has a notch groove 1 formed at the tip of the spindle shaft 1.
M, and is fitted and attached to a part (tip 29
a) is axially outward from the spindle shaft end (tool holder 3).
Side). Another part (side part 29b)
Project from the outer peripheral surface of the spindle shaft 1 toward the outer diameter side (toward the fixing sleeve 33).

On the other hand, a pair of notches 3M are formed on the outer periphery of the flange 3f of the tool holder 3 in correspondence with the notches 1M. When the tool holder 3 is mounted on the spindle shaft 1, the drive key 2 is inserted into the notch groove 3M.
The tool holder 3 and the spindle shaft 1 are positioned by fitting the protruding tip portion 29a of the tool holder 9 to the tool holder 3.

The outer diameter surface of the distal end portion of the spindle shaft 1 has a small diameter, and a step 32 having a height h is formed at a connection portion between the small diameter portion 30 and a large diameter portion 31 following the small diameter portion 30. On the outer surface of the spindle shaft 1, a small diameter portion 30 and a large diameter portion 3 of the spindle shaft are provided.
The sleeves 33 (hereinafter, referred to as fixing sleeves) each having an interference are fitted to 1 and 2. The interference of the fixing sleeve 33 is for holding the taper shank portion 4 of the tool holder 3 fitted in the taper hole 2 by firmly tightening the outer peripheral surface of the end portion of the spindle shaft 1 from the radial direction. The interference must be large enough that the force supporting the tool holder 3 can sufficiently oppose the force applied during machining, and is determined experimentally.

As shown in FIG. 2, a pair of cutout grooves 33M are formed on the outer peripheral surface of the distal end of the fixing sleeve 33 so as to correspond to the drive key 29 at the distal end of the spindle shaft 1. When the fixing sleeve 33 is mounted on the spindle shaft 1, the drive key 29 is mounted by fitting the protruding side portion 29b of the drive key 29 to the outer diameter side into the notch groove 33M.

As shown in FIG. 3, when the drive key 29 is fitted in the notch groove 33M of the fixing sleeve and the fixing sleeve 33 is in the retracted position,
Between the rear end face 29c and the inner face 33c of the notch groove 33M facing the rear end face 29c, a gap δ in the axial direction is interposed when the tool holder 3 is clamped. This gap δ regulates the distance that the fixing sleeve 33 moves forward in the axial direction due to the supply of the pressure liquid. The drive key 29 in the present invention is used for positioning the spindle shaft 1 and the tool holder 3 in the rotational direction. Not only does it function as a stopper that limits the axial movement distance of the fixing sleeve 33.

In this way, the tool holder 3 and the fixing sleeve 33 are integrally positioned with respect to the spindle shaft 1 via the drive key 29, and can be rotated synchronously. On the inner peripheral surface of the fixing sleeve 33, a fluid passage 34 composed of an annular recess is formed at the position of the step 32 on the outer surface of the spindle shaft, and this fluid passage 34 is connected to the connecting portion 3 of the fluid pressure supply pipe.
5 communicates with the outside. The distal end surface 33a of the fixing sleeve 33 is slightly protruded from the axial end surface 1a of the spindle shaft 1 by an axial length γ (for example, about 0.5 to 1 mm).
Abuts on the end face of the flange portion 3f of the tool holder 3 to be locked.

On the other hand, the rear end face 33b of the fixing sleeve 33
Is formed in a stepped shape with concavities and convexities, and faces the front lid 11 of the housing 8 in a non-contact manner through a gap 36 having a labyrinth structure for preventing entry of foreign matter.

Here, the height h of the step 32 of the outer diameter surface of the end portion of the spindle shaft is also the step of the inner diameter of the fixing sleeve 33, and the fixing step 33 is advanced by the fluid pressure using the step. It works to make it work. Since the fixing sleeve advance force is determined by the product of the difference between the inner diameter cross-sectional area of the fixing sleeve 33 before and after the step 32 and the fluid pressure, the height h of the step is related to the set value of the required fluid pressure. Is determined.

Next, the pressure liquid supply structure of the fixing sleeve 33 will be described. At the connecting portion 35 of the fluid pressure supply pipe on the outer diameter surface of the fixing sleeve 33, as shown in FIG. A pressure liquid supply passage 4 communicating with a fluid passage 34 formed of an annular concave portion on the inner peripheral surface of the fixing sleeve 33 is formed in the flat portion 40.
1 is open. On the other hand, the fluid supply nozzle 42 has a diameter smaller than the minimum width dimension of the flat portion 40, and has a flat end 42a at the connection end thereof. Seal member 44
Is fitted with an outer diameter constraint. At the center of the circular concave portion 43, an outlet of the pressure liquid supply path 45 from the pressure liquid supply device P opens.

When the fluid supply nozzle 42 is connected to the connection part 35 of the fluid pressure supply pipe, the spindle shaft 1 stops at a fixed phase by the orientation operation, and the fluid supply nozzle 42 is perpendicular to the flat part 40 of the fixing sleeve 33. Moving from the direction. The plane 42 of the fluid supply nozzle 42
a, the O-ring seal member 44 seals between the flat surface portion 40 and the flat surface 42a of the fluid supply nozzle 42 for connection.

The pressurized liquid supply device P for feeding the pressurized liquid to the annular fluid passage 34 on the inner peripheral surface of the fixing sleeve 33 and the drawbar 25 inserted in the spindle shaft 1 are moved in the direction in which the tool holder 3 is released. The drawbar pressing device D for pressing is connected via control means C. When replacing the tool holder 3, the control means C first turns on the drawbar pressing device D to move the drawbar 25 to the holding release position, and then turns on the pressurized liquid supply device P and turns the tool holder 3 with the fixing sleeve 33. And issues a command signal to release the connection between the tapered hole 2 of the spindle shaft 1 and the tool holder 3 held therein by the drawbar pressing device D and the pressure liquid supply device P.
Is output to each drive circuit. Then, the operation timing of the drawbar pressing and the supply of the pressure liquid to the fixing sleeve 33 is set to A
The control is performed in accordance with the tool change operation in the TC.

The spindle device configured as described above is mounted on a spindle mounting machine base of a machine tool via a flange 9 of a housing 8 thereof. Spindle shaft 1
The pulley 17 at the rear end is connected to a pulley of an output shaft of a drive motor (not shown) by a belt.

Next, the operation will be described. When the tool holder 3 is mounted on the shaft end of the spindle shaft 1, the draw bar 25 of the tool attaching / detaching mechanism is advanced by driving the piston of the draw bar pressing device D against the elasticity of the disc spring 26 (FIG. 5). Unclamped state). In this state, the tapered shank portion 4 of the tool holder 3 carried by the exchange arm from the ATC magazine (not shown) to the spindle shaft 1 is inserted into the tapered hole 2 of the spindle shaft 1. When the flange portion 3f of the tool holder 3 comes to a position close to the fixing sleeve 33, the fluid supply nozzle 42 of the pipe 45 from the pressure liquid supply device P is connected to the pipe connection portion 35 of the fixing sleeve 33. This connection operation may be performed by simply moving the fluid supply nozzle 42 from the direction perpendicular to the flat portion 40 of the fixing sleeve 33 with a connection device (not shown), and simply pressing the flat surface 42a of the nozzle tip against the flat portion 40 of the sleeve, A complicated connection operation and nozzle positioning accuracy are not required unlike a conventional nozzle in which the tip of a nozzle is fitted and connected to a screw hole or a fitting hole. Therefore, automatic connection is possible with one touch, and it is possible to easily cope with the tool changing speed in ATC.

After the connection is completed, the fluid passage 3 on the inner circumference of the sleeve
4 is supplied with hydraulic pressure p. Due to the oil pressure, a radial force acts on the inner diameter surface of the fixing sleeve 33 to expand the inner diameter of the fixing sleeve 33, and the interference of the fixing sleeve 33 with the spindle shaft 1 is released.

At the same time, on the step surface on the inner surface of the fixing sleeve 33 corresponding to the step 32 on the outer surface of the spindle shaft,
A thrust force corresponding to the difference in the inner diameter cross-sectional area acts,
The fixing sleeve 33 advances. As a result, the distal end surface 33a of the fixing sleeve 33 is
f is brought into close contact with the end face. In this state, the tool holder 3 is further pushed. Then, the tapered shank portion 4 of the tool holder 3 is fitted into the tapered hole 2, and the pull stud 22 at the top of the tapered shank portion 4 is fitted into the sleeve 24 at the tip of the tool attaching / detaching mechanism.

At that time, when the drive of the piston of the drawbar pressing device D is released, the drawbar 2
5 retreats. As a result, as shown in FIG. 3, the sleeve 24 moves from the large-diameter space 18a of the through hole 18 to the small-diameter space 18b, and the ball collet 23 of the sleeve is pushed by the inner peripheral surface of the small-diameter space 18b. Protrude inside of 24. Thus, the tool holder 3 is held by pulling the root of the head 22b of the pull stud 22 of the tool holder with the ball collet 23. Since the draw bar 25 is elastically urged rearward by the strong elastic force of the large number of disc springs 26, the draw bar 25 is pulled by this and the inclined surface of the tapered shank portion 4 of the tool holder 3 is brought into close contact with the inner surface of the tapered hole 2. You.

Thereafter, the fluid pressure is released and the fixing sleeve 3 is released.
When the pressure applied to the inner surface of the fixing sleeve 3 is removed, the fixing sleeve 3 is removed.
The inner diameter of the spindle shaft 3 is reduced and the outer surface of the spindle shaft 1 is tightened. At this time, if the speed at which the fluid pressure is released is changed, the force with which the fixing sleeve 33 presses the flange portion 3f of the tool holder 3 can be changed. Therefore, the fluid pressure can be released at an appropriate speed determined by experiments. Choose When the fluid pressure is released, the fluid supply nozzle 40 is retracted to disconnect the fluid supply nozzle 40 and prepare for the operation of the spindle shaft 1.

In the state where the tool holder 3 is clamped and mounted on the spindle shaft 1 in this manner, the fixing sleeve 3
3, the tip surface 33a is kept in close contact with the end surface of the flange portion 3f of the tool holder 3, but there is a gap γ between the end surface of the flange portion 3f and the shaft end surface 1a of the spindle 1. In addition, there is an axial gap between the back surface 33c of the notch groove 33M of the fixing sleeve 33 which has been retracted to the retreat limit position by being pulled by the draw bar 25 and the rear end surface 29c of the drive key 29 opposed thereto. δ intervenes.

When the mounted tool holder 3 is detached (unclamped) from the spindle shaft 1, the fluid supply nozzle 40 is connected to the fixing sleeve 33 again, but before the hydraulic pressure is supplied, the drawbar pressing device D The drawbar 25 is driven forward (ON) to move the drawbar 25 forward. Thus, the grip of the pull stud 22 by the ball 23 is released. However, even at the forward limit of the draw bar 25, since the clearance α is set between the rear end face of the head 22b of the pull stud 22 and the inner face 24b of the inner diameter of the sleeve 24, the tool holder 3 does not protrude. . Therefore, the tapered shank portion 4 of the tool holder 3 remains connected to the tapered hole 2 of the spindle shaft 1 by tightening the fixing sleeve 33 in the reduced diameter state, and the tool holder 3 does not fall off.

Next, the pressure liquid supply device P operates with a time delay set by the control device C, and supplies the hydraulic pressure p to the fluid passage 34 on the inner periphery of the fixing sleeve 33. Due to the oil pressure, the inner diameter of the fixing sleeve 33 is expanded and the fastening of the fixing sleeve 33 is released, and at the same time, a force in the thrust direction acts on the fixing sleeve 33 to move the fixing sleeve 33 forward. As a result, the tool holder 3 protrudes from the fixing sleeve 33 and separates from the spindle shaft 1,
It is carried out with the ATC replacement arm.

The ATC transports and stores the detached tool holder 3 in the magazine, takes out the next new tool holder 3 from the magazine, and transports it again to the spindle device. Then, mounting on the spindle shaft 1 is performed according to the procedure described above, and the replacement operation is completed.

FIG. 6 is a time chart showing each operation of the drawbar pressing, the sleeve oil pressure, and the TAC replacement arm performed by the control device C when the tool holder 3 is attached to and detached from the spindle shaft 1. , (A) shows the case of the present invention, and (b) shows the case of the conventional example.

The timing of starting the forward drive of the draw bar 25 at the time of attachment / detachment is determined by A in both the present invention and the conventional case.
This is at the same time as the timing at which the TC exchange arm grips the tool holder 3 at the tip of the spindle shaft 1. However, conventionally, the tool holder 3 is kicked off from the spindle shaft 1 by the draw bar 25 itself, and the sleeve is not operated at the time of attachment / detachment. On the other hand, in the case of the present invention, the drawbar 2
After the start of the forward drive of 5, the supply of the sleeve hydraulic pressure is started with a predetermined time lag, and the tool holder 3 is kicked off from the spindle shaft 1 by the sleeve. That is, drawbar 2
The tool holder 3 can be pushed out separately from the timing of the forward movement of 5, so that the time lag of the operation of the ATC replacement arm can be easily adjusted. (In the past,
If the operation of the replacement arm is delayed, the tool holder 3 kicked by the drawbar 25 falls off the spindle shaft 1 and hinders replacement.)

When the attachment / detachment is completed, the spindle device waits until the next exchange tool holder 3 is carried, and during that time, the drawbar pressing remains ON in any case.

With respect to the sleeve hydraulic operation, in the case of the present invention, it is kept ON, and the fixing sleeve 33 is maintained in the expanded state. After the tool holder 3 conveyed by the replacement arm is inserted into the spindle shaft 1 and the drawbar pressing is turned off to completely grip the tool holder 3, the sleeve oil pressure is turned off after a predetermined time lag, and the fixing sleeve is turned off. Since the tool holder 3 is tightened at 33, the tool holder 3 can be securely fixed to the spindle shaft 1. The drive key 29 attached to the tip of the spindle shaft 1 prevents the fixing sleeve 33 from falling off between the time when the tool holder 3 is attached and detached and the time when the tool holder 3 is next attached.

On the other hand, in the conventional case, since the drive key 29 is not provided, if the sleeve oil pressure is turned on while the tool holder 3 is removed from the spindle shaft 1, the fixing sleeve 33 falls off. Therefore, the next tool holder 3
Is conveyed and inserted into the spindle shaft 1, and at the same time, the sleeve hydraulic pressure is turned on. If this timing does not match, it becomes difficult to mount the tool holder 3.

Thus, according to this embodiment, the tool holder 3 can be securely and easily automatically mounted on the shaft end of the spindle shaft 1, and the tool holder 3 can be brought into contact with both the tapered surface and the fixing sleeve surface. (Two-plane restraint) enables extremely high rigidity and stable holding, and also high processing rigidity such as cutting, and enables heavy processing with high load and precise finishing processing. In addition, it is possible to sufficiently absorb the dimensional difference between the mounting portions of the tool holder 3 over various types, and the compatibility of the tools is good.

Further, even if the pressurized liquid is supplied to the fixing sleeve 33 when the tool holder 3 is detached from the spindle shaft 1, the drive key 29 can prevent the fixing sleeve 33 from falling off.

When the draw bar 25 is moved to the unclamping position when the tool holder 3 is attached / detached,
The tool bar 3 is first projected by moving the fixing sleeve 33 without projecting the tool bar 3.
5 at a different timing from the start timing of the tool holder 3
Can be protruded, and operation adjustment with the automatic tool changer can be easily performed.

Further, when supplying the pressurized liquid to the fixing sleeve 33, the positioning accuracy between the fluid supply nozzle 42 and the supply port of the fixing sleeve 33 becomes unnecessary, and the pressurized liquid supply device P
The structure becomes simple.

In the above embodiment, the case where the taper shank portion is a long taper BT type tool holder is described. However, the present invention is not limited to this, and the present invention can be similarly applied to a DIN type short taper type tool holder 3A. is there.

Further, the structure of the portion other than the tool holder mounting structure at the tip of the spindle shaft 1 is not limited to the illustrated one, and any other known similar structure may be arbitrarily applied.

[0056]

As described above, according to the first aspect of the present invention,
According to the spindle device described above, a tapered hole is provided at the shaft end of the spindle shaft, and a small-diameter portion and a large-diameter portion are successively installed on the outer diameter surface of the shaft end. A tool holder having a large-diameter flange portion is fitted, and a fixing sleeve is fitted to each of the small-diameter portion and the large-diameter portion of the spindle shaft with an interference, and the small-diameter portion and the large-diameter portion of the fixing sleeve are joined together. By applying a fluid pressure to a fluid passage provided in a connecting portion, the diameter of the fixing sleeve is expanded and advanced to release the fitting between the tapered hole of the spindle shaft and the tapered shank portion of the tool holder. In a spindle device configured to reduce a diameter of a fixing sleeve by removing pressure and clamp a taper shank portion of a tool holder fitted in a taper hole of a spindle shaft. The shaft end of the bundle axis, a drive key for restricting the forward movement distance of the fixing sleeve upon addition of fluid pressure to said fluid passage, placed opposite through an axial clearance with respect to the stationary sleeve. Therefore, even if fluid pressure is continuously applied to the fixing sleeve from the time when the used tool holder attached to the spindle shaft is The drive key prevents the sleeve from moving forward over a predetermined distance, and as a result, the fixing sleeve can be prevented from falling off the spindle shaft.

According to a second aspect of the present invention, there is provided a spindle device for supplying a pressure fluid to a fluid passage of a fixing sleeve of the spindle device according to the first aspect, and a tool holder provided in a tapered hole of the spindle shaft. And a drawbar pressing device for pressing the drawbar in the holding release direction, and when replacing the tool holder, first turn on the drawbar pressing device to move the drawbar to the holding release position, and then turn on the pressure liquid supply device. The taper hole of the spindle shaft is provided with control means for releasing the coupling between the taper hole of the spindle shaft and the tool holder held therein by projecting the tool holder with the fixing sleeve. The tool holder is not pushed out until the tool holder is moved forward by supplying the pressure fluid from the pressure fluid supply device to the fixing sleeve. And it can be out, can extrusion separately from the tool holder to the timing of the movement of the draw bar, an effect that is the operating time adjustment with the result ATC becomes easy.

According to the spindle device of the third aspect of the present invention, in the spindle device of the first or second aspect, a flat portion is provided at an entrance of the fluid passage of the fixing sleeve, and the flat portion is provided on the flat portion. The fluid supply nozzle has a pressure liquid supply structure in which the tip of the fluid supply nozzle is pressed through a seal member and connected to the fluid passage. Therefore, even if the connection between the fluid supply nozzle and the inlet of the fluid passage of the fixing sleeve is rough, it is possible to supply the pressurized liquid from the pressurized liquid supply device to the fixing sleeve. This has the effect of simplifying the structure of the device.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of a spindle device of the present invention.

FIG. 2 is a view taken along line II-II of FIG.

FIG. 3 is an enlarged cross-sectional view of a main part at the time of clamping shown by a cross section taken along line III-III of FIG.

FIG. 4A is a cross-sectional view illustrating an example of a connection structure of a pressurized liquid supply pipe of the present invention, and FIG. 4B is a cross-sectional view taken along the line bb.

FIG. 5 is an enlarged sectional view of a main part at the time of unclamping corresponding to FIG. 3;

6A and 6B are time charts of operation control of a draw bar pressing device and a pressure liquid supply device of a spindle device, wherein FIG. 6A shows the case of the present invention, and FIG. 6B shows the case of a conventional spindle device.

FIG. 7 is an enlarged view of an example of a tool mounting portion in a conventional spindle device.

FIG. 8 is an enlarged view of another example of a tool attachment portion in a conventional spindle device.

FIG. 9 is an enlarged view of still another example of a tool attachment portion in a conventional spindle device.

FIG. 10 is a cross-sectional view illustrating various examples of a connection structure of a pressure liquid supply pipe in a conventional spindle device.

[Explanation of symbols]

 Reference Signs List 1 spindle shaft 2 tapered hole 3 tool holder 3f flange 4 taper shank 25 draw bar 29 drive key 30 small diameter portion 31 large diameter portion 33 fixing sleeve 34 fluid passage δ gap P pressure liquid supply device D draw bar pressing device C control means 40 Flat part 44 Sealing member

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Nishii 2NAK AGAWA Building Asuka Trading Co., Ltd. at 201, Shinga-cho, Kashihara-shi, Nara Prefecture (56) References JP-A-7-178607 (JP, A) Hei 6-312305 (JP, A) JP-A-9-141506 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23B 19/02 B23B 31/06 B23B 31/117

Claims (3)

(57) [Claims] 1. A spindle shaft having a tapered hole for mounting a tool at the shaft end, a small diameter portion having a small diameter at the shaft end side and a large diameter portion connected to the outer surface, and a tapered hole of the spindle shaft. A tool holder having a tapered shank portion to be fitted and a flange portion having a larger diameter than the tapered shank portion, and fitting the fitting portion to the small diameter portion and the large diameter portion of the spindle shaft, and connecting the small diameter portion and the large diameter portion. The part is provided with a fixing sleeve provided with a fluid passage penetrating to the outside, and the fluid pressure is applied to the fluid passage to expand the diameter of the fixing sleeve and advance the shaft in the axial direction so that the tapered hole of the spindle shaft and the tool are formed. Release the fitting with the taper shank of the holder and remove the fluid pressure to reduce the diameter of the fixing sleeve and clamp the taper shank of the tool holder fitted into the taper hole of the spindle shaft A drive key that regulates a forward moving distance of the fixing sleeve when a fluid pressure is applied to the fluid passage, at a shaft end of the spindle shaft, and a shaft with respect to the fixing sleeve. A spindle device characterized by being arranged opposite to each other with a gap in the direction. 2. The spindle device according to claim 1, wherein a pressurized liquid supply device for supplying a pressurized liquid to a fluid passage of the fixing sleeve, and a draw bar for holding the tool holder in a tapered hole of the spindle shaft, in a holding release direction. When the tool holder is replaced, first, the drawbar pressing device is turned on to move the drawbar to the holding release position, and then the pressurized liquid supply device is turned on, and the tool is fixed with the fixing sleeve. A spindle device comprising a control means for releasing a connection between a tapered hole of the spindle shaft and a tool holder held therein by projecting a holder. 3. The spindle device according to claim 1, wherein a flat portion is provided at an inlet of the fluid passage of the fixing sleeve, and a seal member is provided at a tip of the fluid supply nozzle. A pressurized liquid supply structure configured to press a tip of the fluid supply nozzle against the flat portion via the fluid supply nozzle to connect the fluid supply nozzle to the fluid passage.