JP2000005962A - Automatic tool exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease or eliminate overload to a tool exchanging arm when clamping or unclamping a tool, while enabling high-speed action for keeping the tool clamped or unclamped. SOLUTION: In an automatic tool exchanger 50 in which either a tool holder 2 chucked by a tool exchanging arm 45 is unclamped by a spindle and pushed out by a cylinder provided inside the spindle, or the tool holder 2 is clamped against the spindle and exchanged by the tool exchanging arm 45, a cam surface 52 operating at a speed about equal to the speed at which the cylinder provided inside the spindle 4 pushes out the tool holder 2 is formed in a cam 51 for moving the tool exchanging arm 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an automatic tool changer. More specifically, the present invention relates to an improvement in a mechanism for unclamping a tool holder from a spindle or clamping a tool holder to a spindle during tool change.

[0002]

2. Description of the Related Art As shown in FIG. 10, an automatic tool changer 101 is provided to exchange a tool 104 between a tool stocker 102 and a spindle 103. When performing tool change, first, the tool change arm 1
The tool holder 106 chucked at 05 is unclamped from the spindle 103, pushed forward by a cylinder provided inside the spindle 103, and then completely pulled out and replaced by the operation of the tool changing arm 105. .

[0003] As such a forward pushing mechanism,
For example, in a spindle driving device 111 as shown in FIG. 11, a rod 107 in which the spindle 103 moves to a clamp position for holding the tool holder 106 and an unclamping position for releasing the holding of the tool holder 106, and a rod 107
Member 109 for changing the position of the pressure chamber to the clamping position or the unclamping position, and a pressure medium such as oil
8 is provided with pressure applying means (not shown) for changing the position of the piston member 109 to a clamp position or an unclamping position by injecting the piston 107 into the clamp position, and a disc spring 110 for urging the rod 107 toward the clamp position.

In order to exchange the tool holder 106 mounted on the spindle driving device 111 at high speed, a pressure medium is injected into the pressure chamber 108 to change the position of the piston member 109 to the clamp position or the unclamping position. In some cases, means (not shown) is provided, and further, spring means (not shown) for urging the piston member 109 toward the unclamping position is provided.

In such a spindle driving device 111, when changing the rod 107 from the clamp position to the unclamping position in order to exchange the tool 104, the rod 1
Reference numeral 07 moves while receiving the reaction force of the disc spring 110 by the combined force of the pressure of the pressure medium acting on the piston member 109 and the urging force of the spring means. Therefore, when the rod 107 is moved to the unclamping position, the urging force by the spring means can be applied, so that the unclamping force can be increased and the movement of the rod 107 to the unclamping position can be accelerated.

Further, when the pressure medium is switched to move the piston member 109 from the clamp position to the unclamping position, the spring means urges the piston member 109 toward the unclamping position and moves it. For this reason,
Since the piston member 109 can move during the time lag due to the initial response delay in switching the pressure medium, the rod 1
07 can be shortened and the speed can be increased by moving to the unclamping position.

[0007]

However, the speed at which the tool holder 106 is actually pushed by the pneumatically or hydraulically driven internal cylinder depends on the pulling out of the tool changing arm 105 when the cam is driven. It can reach about 20 times the operating speed. In this case, for example, in the automatic tool changing apparatus 101 shown in FIG. 10, if a forward pushing force is applied only to the tool holder 106 while the tool holder 106 is clamped by the tool changing arm 105, the tool changing arm 105 Since such a force is not applied to the center shaft 112, a load such as bending stress is applied to the tool changing arm 105. When a load is continuously applied to the tool changing arm 105 due to such a speed difference, an excessive force is applied by a number of repetitive operations, which may cause noise, abnormal wear or breakage.

Accordingly, the present invention is to reduce or eliminate the overload on the tool changing arm at the time of clamping or unclamping while enabling the high-speed operation of setting the tool to the clamped or unclamped state. It is an object of the present invention to provide an automatic tool changer capable of performing the above operations.

[0009]

According to the first aspect of the present invention, a tool holder chucked by a tool changing arm is unclamped from a spindle by a cylinder provided inside the spindle. In an automatic tool changer that extrudes or clamps a tool holder to a spindle and changes the tool holder with a tool changing arm, a cam provided for moving the tool changing arm uses a cylinder provided inside the spindle. When the tool holder is pushed out, a cam surface which operates at a speed substantially equal to the pushing speed of the cylinder is formed.

Therefore, as the tool holder is pushed forward, the tool exchange arm holding the tool holder can also be pushed forward and moved. In this case, by appropriately setting the shape of the cam surface and the shape of each lever and link moved by the cam surface, the moving speed and the moving width of the tool changing arm can be adjusted to the moving speed and the moving width of the tool holder. it can. If the tool holder and the tool changing arm holding the tool holder are simultaneously moved by the same amount, unnecessary overload is not applied to this arm.

In the automatic tool changer according to the second aspect of the present invention, the cam surface includes a step of pushing the tool changing arm in synchronization with the pushing speed of the cylinder, and a step of pushing the tool changing arm in order to make it move back and forth. It is formed so as to be moved back and forth in two steps, and the front and rear movement speeds in both steps are made different. Therefore, in one stage, the tool changing arm can be moved back and forth at the time of tool changing as before, and in the other stage, the tool changing arm can be moved in synchronization with the tool holder.

According to a third aspect of the present invention, there is provided an automatic tool changing apparatus, comprising: a cam; a roller gear cam provided coaxially with the cam; and a cam follower provided on a center axis of a tool changing arm so as to mesh with the roller gear. By
The tool change arm is moved back and forth and turned. Therefore, in this case, by rotating the cam and the roller gear cam integrally, the tool can be changed by a predetermined forward and backward movement and a turning movement with respect to the tool changing arm.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

1 to 9 show an embodiment of the automatic tool changer according to the present invention. As shown in FIG. 10, the automatic tool changer 50 changes the tool 5 between the tool stocker and the spindle by using the tool changing arm 45. When performing a tool change with the tool changing arm 45, the tool holder 2 is pushed out by a cylinder provided inside the spindle 4 and then the spindle 4 is moved.
The tool holder 2 is extracted and unclamped, or the tool holder 2 is clamped to the spindle 4.

In the present invention, the cam 51 for moving the tool changing arm 45 is formed with a cam surface 52 which operates at a speed substantially equal to the pushing speed of the tool holder 2 by the cylinder. The overload is reduced by preventing bending stress from being applied.

As described above, the present invention is based on the premise that the spindle 4 has a mechanism for pushing the tool holder 2 forward. Hereinafter, the spindle driving device 1 will be described first. I do. In this specification, the term “cylinder” simply refers to a series of hydraulic / pneumatic actuators configured to move the rod 3 back and forth, including the piston member 7, the cylinder peripheral wall 32, the pressure chamber 6, and a fluid. .

As shown in FIGS. 7 to 9, a spindle driving device 1 of the present embodiment comprises a tool 5 held on a tool holder 2 by a spindle 4 rotated by a rotational driving force of a motor (not shown). Is driven to rotate. In this embodiment, the tip side T of the spindle driving device 1 is a tool holder 2
And the proximal end B means the side opposite to the distal end T in the longitudinal direction of the rod 3. In the present embodiment, the spindle driving device 1 is used by being incorporated in a machining head of a machining center.

The spindle driving device 1 has a clamping position (a position on the base end B as shown in FIG. 8) where the spindle 4 holds the tool holder 2 and an unclamping position (FIG. 7) where the holding of the tool holder 2 is released. , A piston member 7 that is accommodated in the pressure chamber 6 and changes the position of the rod 3 to a clamp position or an unclamping position, and a pressure medium that moves the pressure medium to the pressure chamber 6. Pressure applying means (not shown) for changing the position of the piston member 7 to the clamp position or the unclamping position by injecting the piston member 7
And a first spring means 8 for urging the rod 3 toward the clamp position, and a second spring means 9 for urging the piston member 7 toward the unclamping position.

The spindle driving device 1 includes a chuck unit 10 disposed at the most distal end T for holding the tool holder 2, a rotation driving unit (not shown) for rotating the spindle 4, and a rod A clamp operation section 11 for moving the base side B and the base end side B, and a coolant supply section (not shown) arranged at the base end side B and supplying coolant to the tool 5 via the rod 3 and the tool holder 2 And

The rotation drive unit includes a motor, and a pulley and a belt (not shown) for connecting the motor to the spindle 4.

The rod 3 communicates from the chuck section 10 to the coolant supply section. At the center of the rod 3, a coolant circulation hole 12 formed of a through-hole for allowing the coolant from the coolant supply unit to flow through the tool holder 2 is formed. The rod 3 is slidably accommodated inside a cylindrical spindle 4. The spindle 4 communicates from the chuck portion 10 to a position just before the piston member 7,
The casing 13 is rotatably supported by a bearing 14.

First spring means 8 is fitted between rod 3 and spindle 4. The first spring means 8 comprises a large number of disc springs in this embodiment. As shown in FIG. 9, the distal end side T of the first spring means 8 is
And is in contact with the locking step 16 on the inner periphery of the spindle 4 via the. As shown in FIGS. 7 and 8, the proximal end B of the first spring means 8 is in contact with the enlarged diameter portion 18 of the rod 3 via the collar 17. The enlarged diameter portion 18 is formed to have an outer diameter slightly smaller than the inner diameter of the spindle 4.

When no external force is exerted on the rod 3 by the piston member 7, the first spring means 8 retracts the tool holder 2. Rod 3 by piston member 7
Moves to the tip end side T, the entire length of the first spring means 8 is compressed and urged. At this time, the first spring means 8
Urges the rod 3 toward the base end B, that is, toward the clamp position. Further, the first spring means 8 has friction in the circumferential direction of the rod 3 and the spindle 4. For this reason,
The rod 3 rotates simultaneously with the rotation of the spindle 4.

A sleeve 19 slidable with respect to the rod 3 and a piston member 7 slidable and slidable relative to the rod 3 are provided on the base end side B of the enlarged diameter portion 18. I have. A fixed sleeve 20 is provided around the sleeve 19. A stopper 21 is attached around the fixed sleeve 20. The stopper 21 is screwed to the end on the base end side B of the spindle 4. The fixed sleeve 20 is fixed to the spindle 4 by a stopper 21. An O-ring 22 is mounted on the inner peripheral surface of the fixed sleeve 20 to brake the sliding of the sleeve 19 in the axial direction. For this reason, if the enlarged diameter portion 18 moves to the base end side B vigorously and then stops, the sleeve 19 also stops immediately, so that
The sleeve 19 can be prevented from contacting the piston member 7.

The clamp operating portion 11 includes a piston member 7 movable to a distal end side T and a proximal end side B, and a distal end side wall 24 forming a distal end side pressure chamber 23 at the distal end side T of the piston member 7.
A proximal side wall 26 forming a proximal pressure chamber 25 on the proximal side B of the piston member 7; and a distal end formed on the distal side wall 24 for communicating the distal pressure chamber 23 with the outside of the spindle driving device 1. A side communication hole 27, a base side communication hole 28 formed in the base side wall 26 and communicating the base side pressure chamber 25 with the outside of the spindle driving device 1, a front side wall 24 and a base side wall 26.
And a biasing member 29 that biases the piston member 7 toward the distal end T by receiving the biasing force of the second spring means 9.

The piston member 7 is a member constituting a cylinder inside the spindle 4. The piston member 7 pushes the tool holder 2 chucked by the tool changing arm 45 forward, thereby facilitating extraction and changing operations by the tool changing arm 45. It is to make. The piston member 7 has a tubular boss 30 and a disc-shaped piston 31 provided on the outer periphery of the rod 3. There is a slight gap S3 between the boss 30 and the rod 3. Therefore, even if the rod 3 rotates, no friction occurs between the rod 3 and the piston member 7.

When the piston portion 31 moves to the distal end T, that is, to the unclamping position, the distal end T of the boss portion 30 moves through the sleeve 19 to the enlarged portion 18 of the rod 3 as shown in FIG. To move the rod 3 toward the distal end T against the reaction force of the first spring means 8. Further, when the piston portion 31 moves to the base end side B, that is, the clamp position side, as shown in FIG.
Are separated from each other to form a gap S6. For this reason, even if the spindle 4 rotates during clamping, the boss 30 that does not rotate
It is possible to prevent friction from occurring between them.

A cylinder peripheral wall 32 is attached to the outer periphery of the piston portion 31. The distal side wall 24 is disposed on the distal side T of the cylinder peripheral wall 32 and the proximal side wall 26 is disposed on the proximal side B. The base side wall 26, the cylinder peripheral wall 32, and the front end side wall 24 are
And can slide with respect to the casing 13. Further, the cylinder peripheral wall 32, the distal side wall 24, and the proximal side wall 26 form a pressure chamber 6 that accommodates the piston portion 31. O-rings 34, 34 are used at the joining portions between the cylinder peripheral wall 32, the distal side wall 24, and the proximal side wall 26, respectively. Is used, the pressure chamber 6 has high airtightness. Further, a seal ring 36 is mounted on the outer peripheral surface of the piston portion 31. For this reason, the pressure chamber 6 is
The airtightness is maintained in each of the pressure chambers 23 and 25.

The second spring means 9 comprises a rectangular compression coil spring wound with a wire having a rectangular cross section. Therefore, a strong spring can be provided for a small volume. However, it is needless to say that the compression spring is not limited to a rectangular compression coil spring. Here, the spring force of the second spring means 9 is the first spring means.
It is set smaller than the spring force of the spring means 8. For this reason, the second spring means 9 and the first spring means 8 are
When the piston 3 and the piston member 7, the sleeve 19, and the rod 3 are pressed against each other, the rod 3 is located at the base end side B (clamp position).

The spring force of the first spring means 8 and the second spring means 9 is determined by the time required for the first spring means 8 to move the rod 3 toward the clamp position, the piston member 7 and the second
It is preferable to set the movement time of the rod 3 to the unclamping position side by the spring means 9 to be equal.
Thereby, the moving time of the rod 3 to the unclamping position side can be shortened to the same speed as the moving time to the clamp position side.

Each of the communication holes 27 and 28 is provided with a high-pressure air jet nozzle (not shown) as pressure applying means. Further, each communication hole 27 of the piston portion 31,
An annular groove 31a is formed in a portion facing 28. For this reason, when high pressure air is blown into the base end communication hole 28 when the piston portion 31 is at the base end B (clamp position), the high pressure air is blown into the groove 3 on the base end B of the piston portion 31.
Since the piston portion 31 goes around the entirety of 1a, the piston portion 31 can be easily moved to the distal end side T. At this time, the second spring means 9 moves the piston portion 31 via the urging member 29 to the tip side T.
, The moving speed of the piston portion 31 to the unclamping position can be increased. On the other hand, when high-pressure air is blown into the front-end side communication hole 27 when the piston portion 31 is at the front-end side T (unclamping position), the high-pressure air flows around the entire front-end side T groove 31a of the piston portion 31. 31 can be easily moved to the base end side B.

Further, a hook member 37 is fixed to the tip side T of the tip side wall 24 by a bolt 38. The hook member 37 is provided with a small gap S4 with respect to the outer periphery of the stopper 21, and is relatively slidable and rotatable with respect to the stopper 21. Here, at the engagement portion between the hook member 37 and the stopper 21, the hook member 37
Protrudes to the inner peripheral side, and the flange portion 21a of the stopper 21 protrudes to the outer peripheral side at the base end side B. Further, the flange portion 21a of the stopper 21 is accommodated in the circular concave portion of the distal end side wall 24 with a radial gap S8.

For this reason, the stopper 21 and the hook member 37
In addition, there are always gaps S4 and S8 in the radial direction with respect to the tip side wall 24 regardless of the position in the axial direction. Further, the spindle 4 and the stopper 21 are urged toward the distal end side T, and the distal end side wall 2 is
When the hook 4 and the hook member 37 are urged toward the base end side B,
The flange portion 21a of the stopper 21 and the hook member 37 abut in the axial direction, eliminating the axial gap S5, thereby restricting the relative movement.

On the other hand, at the time of clamping (shown in FIG. 8), the piston member 7, the tip side wall 24 and the hook member 37 are urged toward the tip side T by the second spring means 9, so that the flange portion of the stopper 21 is formed. A gap S5 in the axial direction is formed between the hook 21 and the hook member 37, and the stopper 21 and the tip side wall 2 are formed.
4, a gap S7 in the axial direction is generated. For this reason, since there are the gaps S4, S5, S7, and S8, it is possible to prevent contact between the rotating member and the non-rotating member even when the spindle 4 rotates.

When high-pressure air is blown into the proximal communication hole 28 when the rotation of the spindle 4 is stopped, the piston 31 is urged toward the distal end T so as to be separated from the proximal side wall 26. For this reason, the urging force to the tip side T acts on the boss portion 30, the sleeve 19, the rod 3, the first spring means 8, the spindle 4, and the stopper 21. At the same time, high-pressure air is blown into the proximal communication hole 28 so that the proximal side wall 2 is formed.
6, cylinder peripheral wall 32, tip side wall 24, and hook member 37
, A reaction force toward the base end side B acts. These biasing forces in the opposite directions are offset by the tension between the stopper 21 and the hook member 37.

On the other hand, as shown in FIG. 9, a tapered shank 2 of the tool holder 2 is
a is detachable. A tool 5 is mounted on the tip side T of the tool holder 2. A through hole 39 is formed in the center of rotation of the tool holder 2 and communicates with the coolant circulation hole 12 of the rod 3. Therefore, the coolant from the coolant supply unit can be supplied to the tool 5.

A space 40 occupied by the pull stud 2b of the mounted tool holder 2 is formed immediately proximal to the tool holder 2 of the spindle 4 on the base end side B thereof. In addition, a communication hole 41 that communicates the space 40 with the outside of the spindle driving device 1 is formed. A high-pressure air ejection nozzle (not shown) is connected to a portion 42 where the communication hole 41 is exposed to the outside. A collet 43 for holding the pull stud 2b is attached to the base end B of the space 40 occupied by the pull stud 2b. The collet 43 is attached to the end of the rod 3 on the distal end side T. Therefore, when the rod 3 is in the clamp position, the collet 43
Is urged toward the base end B by the rod 3, so that the pull stud 2b of the mounted tool holder 2 is sandwiched and pulled toward the base end B. Thus, the tool holder 2 is pressed and held against the spindle 4.

The configuration of the spindle driving device 1 has been described so far. Next, the automatic tool changing device 50 of the present invention will be described below.

The automatic tool changer 50 of the present invention shown in FIGS. 1 to 3 is provided with a tool changing arm 45 by movement of a cam 51, a first lever 53, a link 54 and a second lever 55.
Of the roller gear cam 5
The tool change arm 45 is provided so as to be able to turn together with the center axis 46 by the movement of the cam follower 6 and the cam follower 57.

The tool changing arm 45 is rotated by a bearing 59 provided on a frame 58 and a bearing 60 provided therein so that a center shaft 46 as a center of rotation can slide in the axial direction. Supported as possible. The sliding width of the tool changing arm 46 back and forth is the second lever 55
Is set as appropriate depending on the swing width of.

The cam 51 forms the timing of the forward and backward movement of the tool changing arm 45, and is provided with a cam surface 52 having a groove having a shape as shown in FIGS. A projection 61 provided at one end of the first lever 53 is engaged with the cam surface 52, and the distance from the center 62 of the cam 51 is changed according to the rotation of the cam 51. Therefore, when the cam 51 rotates, the projection 61 swings and swings the first lever 53 around the swing center 63.

As shown in FIGS. 1 and 2, the first lever 53 is rotatably attached to a swing center 63 provided on a frame 58, and the second lever 55 is rotatably attached to a swing center 64. A link 54 is rotatably provided between a fulcrum 65 at an end of the first lever 53 and a fulcrum 66 at an end of the second lever 55, and the swinging motion of the first lever 53 is applied to the second lever 55. Has communicated. In this case, the shapes of the first lever 53 and the second lever 55 are
The ends of the second and third levers 55 are formed so that a large swing width can be finally obtained.

The distal end portion of the second lever 55 is engaged with the center shaft 46 so as to be rotatable as shown in FIGS. In the present embodiment, as shown in the drawing, a columnar projection 68 at the distal end of the second lever 55 is engaged with a cam follower 67 fixedly attached to the center shaft 46. In this case, although not particularly shown, the protrusion 68 can be moved in the longitudinal direction of the second lever 55, or the portion where the protrusion 68 is engaged with the cam follower 67 is formed in a long hole shape. The change in the distance from the swing center 64 to the cam follower 67 due to the swing of the shaft 55 can be absorbed.

The cam follower 67 is connected to the center shaft 46.
For example, in the present embodiment, the cam follower 67 can move to a position where it comes into contact with the inner surface of the frame 58 or the step portion of the bearing 60 as shown in FIG.

A rotary shaft 69 to which the above-described cam 51 and the like are attached is provided inside the automatic tool changer 50. The rotating shaft 69 is provided in a direction perpendicular to the paper surface as shown in FIG.
Are oriented in a direction different from the longitudinal direction. In FIG. 2, the rotation shaft 69 is represented only by its center line 69c. In addition, although not particularly shown in the figure, FIG.
A drive source for rotating the rotation shaft 69 is provided inside a portion indicated by reference numeral 70 in FIG.

The roller gear cam 56 is attached to the rotating shaft 69. The roller gear cam 56 is provided on the rear side of the cam 51 and coaxially with the cam 51, as shown in FIG. As can be seen from FIG. 3, the roller gear cam 56 is provided at a position immediately above the central shaft 46, and engages with a cam follower 57 provided about the central shaft 46 as shown in FIG. In addition,
In the present embodiment, the roller gear cam 56 is provided separately from the cam 51. However, it goes without saying that these may be provided integrally as a composite cam, for example, as shown in FIG. Around the roller gear cam 56, a groove 72 for engaging with the columnar projections 71,..., 71 of the cam follower 57 is formed obliquely.

The cam follower 57 transmits the rotation of the rotating shaft 69 to the center shaft 46, and is fixed to the center shaft 46 as shown in FIG. The cam follower 57 in the present embodiment is provided with six cylindrical projections 71,..., 71 as shown in the figure, but the number can be changed as appropriate. Further, the columnar projection 71 in the present embodiment is formed in a two-step shape as shown in the figure, and it is also possible to realize a smooth engagement with the groove 72 by making the outside thereof a rotatable ring. However, the shape and the like are not particularly limited to such.

Next, the relationship between the shape of the cam surface 52 and the movement of the tool changing arm 45 will be described.

The cam 51 in this embodiment is provided with a tool changing arm 45 at a speed substantially equal to the speed at which the tool holder 2 is pushed out by the cylinder of the spindle driving device 1.
Is provided with a mechanism for moving the
The tool changing arm 45 is moved back and forth in two steps, a step of pushing out in synchronization with the pushing speed of the cylinder, and a step of pushing out for the original forward and backward movement.

In order to realize such a two-step longitudinal movement, the cam surface 52 in the present embodiment is formed in a shape as shown in FIG. The state of the forward / backward movement of the tool changing arm 45 when the cam 51 having such a shape makes one clockwise rotation will be described below with reference to the embodiment shown in FIG.
Here, the state shown by the solid line in FIG. 4 is the rotation angle of 0 °.

First, in the range of R1 in FIG.
Is an arc shape. Therefore, even if the cam 51 rotates in the range of S1, the projection 61 of the first lever does not move, and the tool changing arm 45 does not move (corresponding to R1 in FIG. 6). The tool change arm 45 does not move back and forth in this manner, but pivots clockwise from a rotation angle of 10 ° to 65 °.

When the cam 51 further rotates, the projection 61 reaches the area R2 of the cam surface 52. The cam surface 52 at this R2 has a shape that slightly increases the diameter from the center 62, and as shown in FIG.
The projection 61 is moved to 5 ° so that the tool changing arm 45 slides smoothly. The speed at this time is about the same as the pushing speed of the tool holder 2 by the cylinder, and the sliding width is also about the same as the pushing width of the tool holder 2 by the cylinder. And rotation angle 7
Since the cam surface 52 from 2.5 ° to 80 ° is again formed in an arc shape, as shown in FIG.
5 stops sliding again in the range of R3. Therefore, it is possible to eliminate the inertia accompanying the sliding of the tool changing arm 45.

The rotation angle is in the range of R4 from 80 ° to 150 °, in which the projection 61 moves, and the first
The lever 53 also swings greatly. Therefore, the tool changing arm 45 also slides largely forward and projects from the device 50 (R4 in FIG. 4). Also on the way,
The tool changing arm 45 starts to rotate clockwise again.
And since the movement of the projection 61 stops at the arc-shaped R5,
The tool changing arm 45 stops in that state.

In the case of R6 from a turning angle of 210 ° to 280 °, the diameter of the cam surface 52 gradually decreases. Therefore, the projection 61 moves in the opposite direction to the above, and starts sliding the tool changing arm 45 backward. The clockwise turning of the tool changing arm 45 is stopped during the backward sliding. Then, in R7, the sliding stops once, similarly to R3, and slides backward again in the range of R8. This R
The sliding speed at 8 is the same as that at R2. When the cam 51 further rotates, it returns to the state of R1 again.

As described above, in the present embodiment in which the cam surface 52 is formed as shown in FIG. 4, a tool changing arm such as R2 and R4 when sliding forward and R6 and R8 when sliding backward. The speed of the forward sliding and the backward sliding of the 45 is divided into two stages. As a result, in the range of R2, that is, in the first moving stage, the sliding speed can be synchronized with the pushing speed of the tool holder 2.

Here, the operation of the automatic tool changer 50 of the present invention when the spindle driving device 1 operates will be described.
A situation where the tool holder 2 is unclamped will be described.

In order to replace the tool holder 2 of the spindle driving device 1, first, the rotation of the tool 5 is stopped, and then the supply of high-pressure air to the distal end communication hole 27 is stopped. As a result, the second spring means 9 presses and moves the piston portion 31 to the distal end side T via the urging member 29. For this reason, the high-pressure air blown next into the proximal pressure chamber 25 can be drawn in, and the boss portion 30 can fill the gap S6 and press the sleeve 19 and the enlarged diameter portion 18.

At the same time, the supply of the high-pressure air to the distal communication hole 27 is stopped, and at the same time, the supply is switched to supply the high-pressure air to the proximal communication hole 28. Here, a time lag occurs due to an initial response delay when switching the supply target of the high-pressure air.
Is moved to the distal end T, so that the rising time can be reduced without wasting time, and the speed of movement of the rod 3 toward the distal end T can be increased. When the rod 3 is moved to the unclamping position on the tip side T, the rod 3 is moved by the combined force of the air pressure acting on the piston member 7 and the urging force of the second spring means 9. For this reason, the unclamping force can be increased as compared with the conventional case in which the rod 3 is moved only by the air pressure acting on the piston member 7, so that the speed of the movement of the rod 3 toward the distal end T can be increased.

The automatic tool changer 50 moves the tool changing arm 45 forward with respect to the rod 3 and the tool 5 moving at a high speed toward the distal end side T so as to synchronize with the movement of the rod 3 and the like. be able to. The forward sliding width at this time is determined by the mechanical relationship between the levers 53 and 55 and the link 54 and the shape of the cam surface 52, and the forward sliding speed at this time is referred to as the rotational speed of the cam 51. Although it is determined including elements,
By appropriately determining these elements, it is possible to simultaneously push the tool 5 and the tool changing arm 45 by the same amount.

Therefore, when the tool 5 is unclamped and pushed forward, an excessive load such as an unnecessary bending stress is not applied to the tool changing arm 45.
The life of the device itself can be extended. Also, in order to increase the speed of the device 50 such as the spindle drive device 1, it is possible to reduce noise as a whole.

Further, in the present invention, the sliding speed of the tool changing arm 45 is changed even in the backward sliding operation in the range of R8 described above. Therefore, the tool holder 5
Can be brought into close contact with the end surface of the spindle 4 at the time of insertion, so that the end surface of the spindle 4 can be protected and the effect of reducing noise can be exhibited.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, the timing of the forward and backward movement and turning of the tool changing arm 45 described with reference to FIG. 6 in the present embodiment is merely an example, and can be appropriately set according to the device.

[0063]

As is apparent from the above description, according to the automatic tool changer according to the first aspect of the present invention, a tool changer which holds the tool holder in accordance with the tool holder being pushed forward. Since the arm can also be pushed forward and moved, the overload on the tool changing arm can be reduced. Further, in this case, the moving speed and the moving width of the tool changing arm can be adjusted to the moving speed and the moving width of the tool holder by appropriately setting the shape of the cam surface and the like, so that the overload can be eliminated. .
Therefore, the noise is reduced with the increase in the speed of the device, and the life of the device is extended since the overload due to the difference in operation speed is eliminated.

In the automatic tool changer according to the second aspect of the present invention, the cam surface is formed in two stages, and in addition to the step of extruding the tool exchanging arm for the original forward and backward movement, the cam surface is tuned to the extrusion speed of the cylinder. Since the step for pushing out is provided, the overload on the tool changing arm can be reduced. In addition, since the tool changing arm is also retracted in two stages, it can be brought into close contact with the spindle end face at reduced speed when the holder is inserted, thereby protecting the spindle end face and reducing noise.

Further, in the automatic tool changer according to the third aspect of the present invention, the cam, the roller gear cam, and the cam follower are used to move the tool change arm back and forth and to rotate, so that the cam and the roller gear cam rotate integrally. By performing the movement, it is possible to perform a tool change by performing a predetermined forward and backward movement and a turning movement with respect to the tool changing arm.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view from the front showing an internal configuration of an automatic tool changer of the present invention.

FIG. 2 is a plan view showing a cross section of the automatic tool changer of FIG.

FIG. 3 is a vertical sectional view taken along a line III-III in FIG. 1 from the right side.

FIG. 4 is a simplified view showing a cam surface of a cam and movements of each lever, link, and cam follower.

FIG. 5 is a diagram showing an example of a composite cam including a cam and a roller gear cam.

FIG. 6 is a graph showing an example of timing of forward and backward movement and turning of a tool changing arm.

FIG. 7 is a side view showing a main part when the spindle drive device is in an unclamped state.

FIG. 8 is a side view showing a main part when the spindle driving device is in a clamped state.

FIG. 9 is a side view showing the chuck portion when the spindle driving device is in a clamped state.

FIG. 10 is a schematic view showing the entirety of a conventional automatic tool changer.

FIG. 11 is a longitudinal sectional view showing a conventional spindle drive device.

[Explanation of symbols]

 2 Tool Holder 4 Spindle 45 Tool Change Arm 46 Center Axis 50 Automatic Tool Changer 51 Cam 52 Cam Surface 56 Roller Gear Cam 57 Cam Follower

Claims (3)

[Claims] 1. A tool holder chucked by a tool changing arm is unclamped from a spindle and pushed out by a cylinder provided inside the spindle, or the tool holder is clamped to the spindle and the tool changing arm is clamped to the spindle. In the automatic tool changer that is configured to change the tool holder, a cam for moving the tool changing arm, a cylinder provided inside the spindle, when the tool holder is extruded by the cylinder, the pushing speed of the cylinder is reduced. An automatic tool changer wherein a cam surface which operates at substantially the same speed is formed. 2. The cam surface is formed so as to move the tool changing arm back and forth in two steps, a step of pushing the tool changing arm in synchronization with a pushing speed of the cylinder, and a step of pushing the tool changing arm to perform an original longitudinal movement. 2. The automatic tool changer according to claim 1, wherein the front and rear movement speeds in the two stages are different. 3. The tool changing arm is moved forward and backward by the cam, a roller gear cam provided coaxially with the cam, and a cam follower provided on a center axis of the tool changing arm so as to mesh with the roller gear. 3. The automatic tool changer according to claim 1, wherein the automatic tool changer is turned.