JPH09272036A - Tool holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool holder capable of spot facing and chamfering at a fixed quality level even if there are dimensional errors in the workpiece. SOLUTION: Mounting sections 100, 101 and 102 for the spindle SP of a machine tool are supported on the holder body 10 provided in the rear end of a tool holder so as to be able to move toward the holder body 10 and in the axial direction of the spindle SP (in the direction of a center line CL), and a movable shaft 11, in which a tool TL can be secured, engaging mechanisms 12C and 112, at which the holder body 10 and the movable shaft 11 are engaged in the peripheral direction and restriction mechanisms 15, 16, 17, 19 and 20, which can restrict the movable body 11 at optional positions in the axial direction mentioned above, in the head end of the tool holder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holder mounted on a machine tool such as a machining center.

[0002]

2. Description of the Related Art When a machining center is used to form, for example, a spot facing portion or a chamfered portion on the back side of a through hole of a workpiece (the front and back are distinguished based on the state in which the workpiece is viewed from the spindle side), the following procedure is used. Processing is being done. First, attach the tool holder to which the back facing or back chamfering tool is fixed to the spindle of the machining center, and then insert the tool holder into the through hole of the machining center with the tool eccentric from the through hole of the workpiece. And the workpiece are moved relative to each other, whereby the cutting edge portion of the tool is projected to the opposite side of the through hole. After that, rotate the tool by aligning the core of the tool and the through hole,
Further, the tool is pulled back to the side of the through hole, and the mouth of the back side of the through hole is processed by the cutting blade.

The tool holder used for this type of machining fixes the tool in both the axial direction and the circumferential direction, and the tool holder and the tool cannot move relative to each other. Therefore, when the tool holder is moved with respect to the work, the tool is moved with respect to the work in the same manner.

[0004]

In the above-mentioned back facing or back chamfering, the work is a cast product, and the back side of the work is the casting surface (the surface formed in the casting stage) without any surface processing. There are times. Since the casting surface has a much larger dimensional error than the machined surface, in the processing using the conventional tool holder, the tool holder and the workpiece are moved according to the coordinate values and the movement amount specified in advance in the machining center. As a result, the amount of spot facing and the amount of chamfering change depending on the error of the casting surface, and the processing quality cannot be kept constant. If the casting surface is surface-processed in order to maintain the processing accuracy, the number of processing steps increases and the cost increases. Depending on the shape of the work, surface processing on the back side may not be possible.

According to the present invention, even if the workpiece has a dimensional error,
An object of the present invention is to provide a tool holder capable of performing counter boring, chamfering and the like with a constant quality.

[0006]

Hereinafter, the present invention will be described with reference to the drawings showing embodiments of the present invention. However, the present invention is not limited to the illustrated embodiment.

According to a first aspect of the present invention, there is provided a holder body 10 having mounting portions 100, 101 and 102 for the spindle SP of a machine tool provided at a rear end thereof, and an axial direction of the spindle SP (center line CL).
The movable body 11 supported by the holder body 10 in a state of being movable in the direction (1), and the tool TL can be mounted on the tip of the movable body 11, and the engaging means 12C for engaging the holder body 10 and the movable body 11 in the circumferential direction. 112 and restraining means 15, 16, 17, 19 capable of restraining the movable body 11 at any position in the axial direction.
The above-mentioned object is achieved by a tool holder with 20 and.

In this invention, the tool holder is attached to the spindle SP to release the restraint of the movable body 11 by the restraining means, and in that state, the spindle SP of the machine tool and the workpiece W (see FIG. 6) are moved in the axial direction. When the tool TL is gradually approached, the tool TL hits the work W in the middle of its operation, and thereafter, the tool TL and the movable body 11 stand still at a certain position (position when hitting the work) with respect to the work W, while the holder main body is being held. 10 and the spindle SP move integrally with the work W. At this time, if the amount of movement of the holder body 10 with respect to the movable body 11 is set according to the position error of the processing target portion W2 of the work W, the cutting start position of the tool TL into the work W (the axis line) regardless of the size of the error. The movable body 11 can be restrained by the restraining means in such a state that it is temporarily stopped at a position where the cutting depth in the direction is zero). From this state, the holder main body 10 and the movable body 11 are integrally moved in the axial direction while rotating the holder main body 10 by the spindle SP, whereby the work W
Can be subjected to a desired amount of processing.

According to the invention of claim 2, in the tool holder of claim 1, the movable body 1 is movable in the axial direction.
A driving body 17 that is provided on the outer peripheral side of 1 and has a tapered surface 170 that is inclined on the inner peripheral side with respect to the axial direction;
The restraint means is provided with restraint bodies 15 and 16 arranged between the tapered surface 170 of the driving body 17 and the outer peripheral surface of the movable body 11 so as to be movable in the radial direction of the movable body 11. According to the present invention, when the driving body 17 is moved in the axial direction, the displacement of the driving body 17 is restricted by the tapered surface 170.
6 is converted into the displacement in the radial direction. Restraint body 15,
When 16 is displaced toward the center of the movable body 11 in the radial direction,
The outer peripheral surface of the movable body 11 is pressed by the restraining bodies 15 and 16 to be restrained in the axial direction. The restraint bodies 15 and 16 are movable bodies 1
When it is displaced outward in the radial direction of 1, the restraint bodies 15, 16
The pressing of the movable body 11 due to is released, and the movable body 11 becomes movable in the axial direction.

According to the invention of claim 3, in the tool holder of claim 2, the inclination θ of the tapered surface 170 with respect to the axial direction is set to be smaller than 45 °. According to the present invention, the force F1 for driving the driving body 17 in the axial direction is magnified by the tapered surface 170 and transmitted to the restraining bodies 15 and 16 (see FIG. 5).

According to a fourth aspect of the invention, in the tool holder according to the second aspect, the driving body 17 is arranged in the direction in which the movable body 11 is constrained.
The restraining means is provided with a driving body urging means 19 for urging the driver. According to the present invention, it is not necessary to supply the driving force for restraining the movable shaft 11 from the outside of the tool holder.

According to a fifth aspect of the invention, in the tool holder according to the second aspect, the restraining means includes the fluid pressure cylinder 30 capable of driving the driving body 17 in the direction in which the restraint of the movable body 11 is released. Therefore, the air pressure of the machining center,
The movable body 11 can be restrained or released using hydraulic pressure or the like.

According to a sixth aspect of the invention, in the tool holder according to the first aspect, the movable body urging means 13 for urging the movable body 11 toward the mounting portion side of the holder body 10 is provided. According to the present invention, when the restraint of the movable body 11 is released, the movable body urging means 13 retracts the movable body 11 toward the rear end side of the holder body 10. When the tool spindle TL is abutted against the back surface side of the work W from this state and the spindle SP is retracted with respect to the work W, the holder body 10 and the movable body 1
And 1 relatively move in the axial direction against the movable body urging means 13.

[0014]

1 shows an example of a tool holder to which the present invention is applied. The upper side of the center line CL in FIG. 1 shows the appearance of the tool holder, and the lower side shows the cross section. The right side of the figure is the tip end side of the tool holder, and the left side is the rear end side of the tool holder. The state where the tool holder is viewed from the tip side (arrow II
The state (as viewed from the direction) is shown in FIG.

As is apparent from FIG. 1, the tool holder is
Holder body 1 mounted on the spindle SP of a machining center
It has 0 and a movable shaft 11. On the rear end side of the holder body 10, a taper shank 100 that is inserted into the taper hole TH of the spindle SP, a key groove 101 that meshes with a spindle key KY for rotation transmission mounted on the front surface of the spindle SP, and a tool for a machining center. A grip flange 102 to be gripped by an exchange device (not shown) is provided. These elements 1
00 to 102 are well-known ones commonly provided in tool holders for machining centers, and detailed description thereof will be omitted.

Inside the holder body 10, there is provided a hollow portion 103 that opens toward the tip of the tool holder. Hollow part 10
A direct acting ball bearing 12A and a metal bearing 12B are attached to the shaft 3 coaxially with the center line CL. Movable shaft 1
1 is inserted into the hollow portion 103 while fitting its outer peripheral surface to the ball bearing 12A and the metal bearing 12B, and is movably supported on the center line CL. As shown in FIG. 3, the holder body 10 has a threaded pin 1 from the outer peripheral side.
2C is screwed in, and the tip of the pin 12C is movable shaft 11
Is inserted into the key groove 112 of the. As a result, the holder body 1
Rotation can be transmitted from 0 to the movable shaft 11. The key groove 112 is formed sufficiently longer in the direction of the center line CL than the diameter of the pin 12C. The ball bearing 12A is changed to a ball spline, and a threaded pin 12C and a key groove 11 are provided.
2 may be omitted.

A flange 111 is provided at the rear end of the movable shaft 11, and a coil spring 13 is attached between the flange 111 and the stopper 104 of the holder body 10.
The movable shaft 11 is biased toward the rear end side of the tool holder by the repulsive force of the coil spring 13 and abuts against the stopper 104. A sleeve 14 to which the tool TL is detachably mounted is attached to the tip end side of the movable shaft 11. The tool TL has the cutting edge CE formed on the blade body CB as the center line C.
The chamfering tool is inclined at 45 ° with respect to L, and is configured as a back chamfering tool by mounting the cutting edge CE toward the tool holder side. The sleeve 14 is a side lock type for a straight shank. Needless to say, the attachable tool TL and the sleeve 14 are not limited to the illustrated modes.

As shown in detail in FIGS. 3 and 4, the holder body 10 has through holes 105 extending radially through the holder body 10 at an equal pitch in the circumferential direction of the tool holder.
Pieces) are formed. The clamper 15 is provided in each through hole 105.
Are movably inserted in the axial direction of the through holes 105, and steel balls 16 are arranged outside the clampers 15. Each steel ball 16 comes into contact with a clamp ring 17 fitted on the outer circumference of the holder body 10. Clamp ring 1
7 is movable in the direction of the center line CL, and a tapered surface 170 that is closer to the center line CL side toward the tip side of the tool holder is formed at the contact portion with each steel ball 16.
Therefore, when the clamp ring 17 moves to the rear end side of the tool holder (left side in FIGS. 1 and 4), the clamper 15 is pushed toward the center side in the radial direction via the steel ball 16, whereby the outer peripheral surface of the movable shaft 11 is pushed. Is pressed by the clamper 15 to restrain the movable shaft 11 (see FIG. 4A). On the other hand, when the clamp ring 17 moves in the opposite direction to the above, the taper surface 170 retreats outward in the radial direction with respect to the steel ball 16, and the clamper 15 releases the restraint of the movable shaft 11 (FIG. 4).
(B)).

In order to drive the clamp ring 17 to the rear end side of the tool holder, a coil spring 19 and a ring retainer 20 are provided between the clamp ring 17 and the flange 18 fixed to the tip of the holder body 10. A plurality of coil springs 19 are provided around the center line CL at an appropriate pitch. The ring retainer 20 is fitted onto the outer periphery of the holder body 10 in a state of being movable in the direction of the center line CL, and receives the repulsive force of each coil spring 19 to retain the clamp ring 17 toward the rear end side of the tool holder.

FIG. 5 shows a load state when the clamp ring 17 is pushed by the ring retainer 20.
Since the inclination angle θ of the taper surface 170 with respect to the direction of the center line CL is set to a sufficiently small value (for example, about 10 to 15 °), the taper surface 170 with respect to the force F1 by which the ring retainer 20 presses the clamp ring 17. An extremely large force F2 acts in the direction normal to the force F3, so that the force F3 that pushes the clamper 15 in the radial direction of the tool holder is also sufficiently expanded with respect to the original force F1. As a result, the movable shaft 11 is moved to the clamper 15
Can be firmly restrained. In addition, in order to obtain such an expansion effect of the clamping force, the inclination angle θ may be set to less than 45 °.

In order to drive the clamp ring 17 toward the tip side of the tool holder and release the restraint of the movable shaft 11, the piston 2 is located closer to the rear end side of the tool holder than the clamp ring 17.
1 is provided. Bearing 22 on holder body 10
The piston 21 is supported coaxially with the holder body 10 and the clamp ring 17 and movably in the direction of the center line CL by a cylindrical cylinder tube 23 rotatably attached via. Inner circumference of piston 21 and holder body 10
A gap is provided between the outer periphery of the piston 21 and the outer periphery of the piston 21 so that the piston 21 can stand in the circumferential direction with respect to the rotation of the holder body 10. A space between the inner peripheral surface of the cylinder tube 23 and the outer peripheral surface of the piston 21 is hermetically sealed by a ring seal 24 attached to the piston 21.

The piston 21 is urged toward the rear end side of the tool holder by the coil spring 25 held by the cylinder tube 23 and abuts against the ring-shaped cylinder head 26. The cylinder head 26 is rotatably supported by the holder body 10 via a bearing case 27 and a pair of bearings 28. Therefore, the cylinder head 26 can be stationary in the circumferential direction with respect to the rotation of the holder body 10, and cannot be moved relative to the holder body 10 in the direction of the center line CL. Inner peripheral surface of cylinder head 26 and piston 21
A ring seal 29 mounted on the cylinder head 26 hermetically seals the space between and.

An air supply hole 260 is formed in the cylinder head 26 so as to open toward the piston 21. When the compressed air is introduced into the air supply hole 260, the pressure pushes the piston 21 toward the clamp ring 17 side, whereby the clamp ring 17 moves to the tip side of the tool holder and the constraint of the movable shaft 11 by the clamper 15 is released. (See FIG. 4B). When the air pressure from the air supply hole 260 decreases, the force of the coil spring 25 causes the piston 2 to move.
1 is pushed back to the cylinder head 26 side, whereby the clamp ring 17 is returned to the position of FIG. 4 (a) and the movable shaft 11 is restrained. As is clear from the above, the piston 21, the cylinder tube 23, the coil spring 25, the cylinder head 26, and the ring seals 24, 29 constitute a single-acting air cylinder 30.

Air supply hole 26 from the machining center side
In order to supply compressed air to the cylinder head 26 and the bearing case 27, the block 3 is provided at one place on the outer circumference.
1 is fixed (see FIG. 2), and an air introduction pipe 32 is attached to the block 31 thereof. The air introduction pipe 32 is movable in the direction of the center line CL, and is biased toward the rear end side of the tool holder by the coil spring 33. When the tool holder is attached to the spindle SP, the rear end of the air introduction pipe 32 is abutted against the block BL fixed to the spindle housing (not shown) of the machining center. As a result, block B
The air supply hole AS of L is the central hole 3 of the air introduction pipe 32.
20, chamber 310 of block 31 and internal flow path 31
The compressed air can be supplied from the machining center to the air cylinder 30 by being connected to the air supply hole 260 of the air cylinder 30 via the No. 1.

A dog 34 is mounted on the outer periphery of the air introducing pipe 32 so as to be movable in the direction of the center line CL. When the tool holder is removed from the spindle SP, the dog 34 is urged by the coil spring 35 toward the rear end side of the tool holder, and the key portion 340 thereof is fitted into the key groove 106 of the holder body 10. In this state, the holder main body 10 and the dog 34 are engaged with each other in the circumferential direction, so that the air introduction pipe 32, the block 31, and the air cylinder 3 with respect to the holder main body 10.
0 becomes unrotatable, and the keyway 101 of the holder body 10
The angle φ between the formation position of the block and the mounting position of the block 31 and the air introduction pipe 32 is maintained at a constant value (see FIG. 2).

Here, when the tool is changed at the machining center, the spindle SP rotates and the spindle key KY is indexed to a fixed position in the circumferential direction (this rotation is known as the spindle orientation operation). The spindle key KY and the block BL at that time are the same as the above-mentioned key groove 101.
Similarly to the positional relationship between the air introduction pipe 32 and the air introduction pipe 32, they are displaced from each other by the same angle φ in the same direction. Accordingly, the air introduction pipe 32 can be aligned with the block BL when the tool holder is mounted, and both can be reliably abutted against each other.

When the tool holder is mounted on the spindle SP,
The bolt 36 attached to the dog 34 is the block BL
(It may be replaced with another component around the spindle.) As a result, the key portion 340 of the dog 34 is disengaged from the key groove 106 and the holder body 10 and the air introduction pipe 3 are removed.
The engagement with 2 in the circumferential direction is released. At the same time, the block BL and the air introduction pipe 32 are engaged with each other in the circumferential direction of the main shaft SP (the engagement state is not shown in the drawing), whereby the air introduction pipe 32, the block BL, and the air cylinder 30 are formed. It is restrained in the circumferential direction. Therefore, each of the above elements 30
The parts 32 to 32 are separated from the rotation of the spindle SP and the holder body 10 and are stationary in the circumferential direction.

In the above structure, the force of the coil spring 19 is used to restrain the movable shaft 11 and the restraint is released by pneumatic pressure. Therefore, the tool holder is movable in the state where the tool holder is removed from the spindle SP. The shaft 11 cannot move in the direction of the center line CL. Therefore, when the tool holder is held by the tool changer or the tool magazine, the movable shaft 11 does not move freely. In addition, when the supply of compressed air is undesirably cut off due to a power failure or the like while mounted on the main shaft SP, the movable shaft 11 is immediately restrained by the force of the coil spring 19. Therefore, safety is high. However, the movable shaft 11 may be restrained by pneumatic pressure, hydraulic pressure, or the like.

Next, an example of a processing procedure using the above tool holder will be described with reference to FIG. Note that FIG. 6 corresponds to FIG.
This is an example in which the back surface chamfering tool TL shown in FIG. Since the center line CL of the tool holder when the tool holder is attached to the spindle SP of the machining center coincides with the axis line of the tool TL, in the following,
The center line CL may be referred to as a tool axis line for description.

In the machining procedure of FIG. 6, first, the tool holder is advanced with respect to the work W to insert the tool TL attached to the movable shaft 11 into the through hole W1, and as shown in FIG. The blade body CB is projected to the opposite side of the through hole W1.
At this time, the tool axis line CL is eccentric to the side opposite to the cutting edge CE with respect to the center line AX of the through hole W1. Next, FIG.
As shown in (b), the tool axis line CL is aligned with the center line AX of the through hole W1, and the tool holder is retracted (movement in the direction of arrow R) toward the through hole W1 side along the tool axis line CL. At this time, the constraint of the movable shaft 11 by the clamper 15 is released.

By the retreat operation of the tool holder described above, the cutting edge CE of the tool TL is moved through the through hole W1 as shown in FIG. 6 (c).
Although it collides with the mouth W2 on the back side of the holder body 10, the holder body 10 is continuously retracted thereafter. At this time, FIG. 6 (d)
As shown in FIG. 5, since the tool TL is locked to the work W, the movable shaft 11 also stands still in the direction of the tool axis line CL, while the holder body 10 separates from the work W while compressing the coil spring 13. Retreat in the direction. Therefore, even if there is an error in the position of the mouth W2 of the work W, if the holder main body 10 is retracted more than the position shown in FIG. The cutting edge CE always hits the mouth W2 on the way.

The movable shaft 11 is restrained by the clamper 15 when the holder main body 10 is retracted to a predetermined position. Then, while rotating the tool TL, the holder body 10 is retracted in the direction of the tool axis line CL to chamfer the mouth W2 of the through hole W1. If the amount of movement at this time is controlled on the side of the machining center, the chamfering amount C can be kept constant even if the back surface of the work W is a surface with low dimensional accuracy such as a casting surface. After machining is complete, the tool axis C is the same as in Fig. 6 (a).
The tool TL is pulled out from the through hole W1 by decentering L from the center line of the through hole W1. In the above description, the tool holder is moved with respect to the work W in the direction of the tool axis CL, but depending on the configuration of the machining center, the work W may be moved.
The side may be moved.

In the above embodiment, the coil spring 13 as the movable body urging means may be omitted. In this case, for example, before machining, the tool TL is brought into contact with an appropriate position on the front surface side of the work W to move the movable shaft 11 to the position shown in FIG. 1, and the machining can be carried out from that state by the procedure shown in FIG. The present invention is not limited to the case of processing the back surface side of the work, but can be applied to the case of processing the front surface side. In this case, the urging direction of the movable shaft 11 by the coil spring 13 in FIG. 1 is reversed, and the spindle is further advanced to the work side from the state where the tool is abutted against the front surface side of the work W to move the movable shaft 11 to the tool. It may be pushed into the tip of the holder.

[0034]

As described above, according to the present invention, the tool mounted on the tool holder can be moved relative to the spindle of the machine tool in the axial direction and can be restrained at any position. Even if the target portion has a dimensional error, the work can be processed to have a predetermined dimension regardless of the dimensional error. As a result, there is no need to surface-machine the target part of the workpiece prior to the target processing (for example, chamfering or spot facing), so that the number of processing steps can be reduced and cost reduction can be achieved. Moreover, in the invention of claim 2,
The movable body can be restrained at any position in the axial direction simply by driving the drive body located on the outer peripheral side of the movable body in the axial direction of the spindle, so compressed air or hydraulic pressure introduced to the tip of the spindle of a machine tool such as a machining center. Can be used to perform at least one of the restraint and the restraint release of the movable body. According to the third aspect of the present invention, the force for driving the driving body in the axial direction of the main shaft can be enlarged and transmitted to the restraining body, so that the movable body can be tightly restrained and can endure high-load machining. In the invention of claim 4,
Since the driving force for restraining the movable body can be generated inside the tool holder, the movable body can be restrained when the tool holder is not mounted on the spindle, and the force for releasing the restraint of the movable body can be increased. The safety can be enhanced by immediately restraining the movable body when it is lost undesirably. In the invention of claim 5,
Since the movable body can be restrained or released by using the air pressure or hydraulic pressure supplied to the tip side of the main shaft of the machining center, compared with the case where the driving force for both restraint and restraint release is generated in the tool holder. Thus, the mechanism inside the tool holder is simplified. In the invention of claim 6, since the movable body can be moved to the rear end side of the holder body in advance,
The procedure for performing spot facing or chamfering on the back side of the work is simplified.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a tool holder according to an embodiment of the present invention.

FIG. 2 is an arrow view from the direction of arrow II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged view showing an operation of a main part of the tool holder shown in FIG.

FIG. 5 is a sectional view taken along the line VV of FIG. 3;

FIG. 6 is a diagram showing an example of a processing procedure using the tool holder of FIG. 1.

[Explanation of symbols]

 10 ... Holder main body 11 ... Movable shaft (movable body) 13 ... Coil spring (movable body urging means) 12C ... Threaded pin (engaging means) 15 ... Clamper 16 ... Steel ball 17 ... Clamp ring (driving body) 19 ... Coil spring (driving member urging means) 20 ... Ring retainer 21 ... Piston 23 ... Cylinder tube 24, 29 ... Ring seal 25 ... Coil spring 26 ... Cylinder head 30 ... Air cylinder (fluid pressure cylinder) 112 ... Key groove (engagement) Means) SP ... Machining center spindle W ... Work

Claims (6)

[Claims] 1. A holder main body having a mounting portion for a main shaft of a machine tool provided at a rear end, and a holder main body movably supported in the axial direction of the main shaft and having a tool mountable at the front end. A body, an engaging means for engaging the holder body and the movable body in a circumferential direction, and a restraining means capable of restraining the movable body at an arbitrary position in the axial direction. Tool holder. 2. A driving body, which is provided on an outer peripheral side of the movable body in a state of being movable in the axial direction and has a tapered surface inclined on the inner peripheral side with respect to the axial direction, and the movable body. 7. The restraint means includes a restraint body disposed between the tapered surface of the drive body and an outer peripheral surface of the movable body in a state of being movable in the radial direction of the restraint means. The tool holder described in 1. 3. The tool holder according to claim 2, wherein the inclination of the tapered surface with respect to the axial direction is smaller than 45 °. 4. The tool holder according to claim 2, wherein the restraint means includes a drive body biasing means for biasing the drive body in a direction in which the movable body is restrained. 5. The tool holder according to claim 2, wherein the restraint means includes a fluid pressure cylinder capable of driving the drive body in a direction in which the restraint of the movable body is released. 6. The tool holder according to claim 1, further comprising movable body urging means for urging the movable body toward the mounting portion side of the holder body.