JP2008272898A - Unclamping method of tool in machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an unclamping method of a tool in a machine tool accurately moving a draw bar and executing with a small force and at high speed. <P>SOLUTION: In the unclamping method of the tool, a drive device 8 for moving the draw bar 9 in a spindle 3 to the unclamping direction is provided, and the drive device 8 is equipped with a cylinder means, a link mechanism 2 capable of transmitting the power from the cylinder means to the draw bar 9, and a cam member 4 juxtaposed to the link mechanism 2. The draw bar 9 is moved to the unclamping direction based on both the power transmission action associated with a full-time pressurization by the cylinder means and the rotation drive of the cam member 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an unclamping method in which a tool mounted on a spindle of a machine tool is detachable.

Conventionally, since many tools are employed in machine tools such as machining centers, it is necessary to efficiently perform attachment and detachment operations such as tool replacement. For this purpose, an automatic tool changer is installed and automatically performed. However, since such work time is included in the machining time, it is required to perform it more efficiently.
However, this type of unclamping means normally unclamps the tool mounted on the main shaft side by moving the draw bar in the main shaft in the axial direction.

Therefore, as a means for unclamping the tool from the spindle of the machine tool, a coil spring that biases in the unclamping direction is inserted into one pressure chamber of the air cylinder that serves as the drive source, and the air cylinder is driven to unclamp side. There has been proposed one in which the urging force of the coil spring in the same direction is assisted in starting (see, for example, Patent Document 1).
JP 2001-198758 A

  According to the above configuration, it is considered that the urging force of the coil spring can assist the start by driving the air cylinder and increase the start speed. However, to be able to assist the coil spring with a stable urging force, the effective length of the spring must be set to a sufficiently large spring constant, and the pressure chamber into which the spring is inserted is enlarged to accommodate it. There is a concern to do. In addition, the coil spring once inserted has a practical instability factor such as lack of versatility because it is not easy to adjust or detach from the outside. On the other hand, the power of the air cylinder is difficult to control concretely, such as stopping the draw bar to obtain the desired displacement (stroke) accurately. It has problems such as incurring loss.

  In order to solve the above-described problems, an object of the present invention is to provide a tool unclamping method in a machine tool capable of unclamping at high speed with a small force while accurately moving the draw bar in the axial direction. To do.

  In order to achieve the above object, a method for unclamping a tool in a machine tool according to the present invention is to unclamp a tool attached to the spindle by moving a draw bar in the spindle in the axial direction, The draw bar is urged in the clamping direction by the elastic force of the elastic member, and includes a driving device that moves the draw bar in the unclamping direction against the urging force. The driving device includes cylinder means and the cylinder means. A link mechanism that can transmit power from the cylinder to the draw bar, and a cam member that is provided in parallel with the link mechanism, and both power that is always applied by the cylinder means and rotationally driven by the cam member. The main feature is that the draw bar is moved in the unclamping direction based on the transmission action.

  According to the above means, when the draw bar is moved in the unclamping direction, the load of the cam member can be a small load corresponding to a differential pressure load between the urging force of the draw bar and the power from the cylinder means. Therefore, the cam member can be driven to rotate smoothly with a small force, and it is possible to provide a tool unclamping method in a machine tool that can be accurately controlled by the cam member and can move the draw bar at a high speed.

(First embodiment)
1 to 6 show a tool unclamping apparatus in a machine tool according to a first embodiment of the present invention, and FIGS. 1A, 1B, and 1C are longitudinal front views showing different operation modes in order of operation. 2 is a front view of the cam member, FIG. 3 is an operation explanatory view showing movement displacement (corresponding to a stroke) accompanying rotation of the cam member, FIG. 4 is an enlarged view of the main part of FIG. 1A, and FIG. 6 is a rear view of FIG. 4 and corresponds to the left side view of FIG.

  First, the basic form of the clamping / unclamping apparatus shown in the present embodiment will be described. As shown in FIG. 1A, for example, the outline of the clamping / unclamping apparatus is the first cylinder means which is one driving source necessary for unclamping. And a main shaft 3 having a draw bar 9 that is movable in the vertical axial direction via a link mechanism 2 as a means for directly transmitting movement displacement as power by the air cylinder 1. It is arranged. A cam member 4 driven by a cam drive source, which will be described later, is arranged in parallel with the link mechanism 2, and the cam member 4 functions particularly effectively as a displacement transmitting means as will be described later. In this way, a so-called drive device 8 that generates power for moving the draw bar 9 of the main shaft 3 is located directly above the main shaft 3 and is a main force element such as the first air cylinder 1, the link mechanism 2, and the cam member 4. It comprises the structure which comprised.

  Hereinafter, specific description will be given with reference to FIGS. 4 to 6 as appropriate. First, the cylinder means constituting the driving device 8 is in the first air cylinder 1 composed of a double-acting air cylinder, and includes a cylinder rod 5 that can be displaced in the vertical direction in accordance with the pressure change of the pressure chamber 1a. The downward displacement of the rod 5 is guided vertically in the vertical direction by a cylindrical upper bearing 6a. Therefore, the pressurizing power by the first air cylinder 1 is transmitted to the cylinder rod 5 integrally.

  The first air cylinder 1 is fixed to the upper part of a box-shaped main case 7. The main case 7 has a hollow box shape so as to surround the link mechanism 2 and the cam member 4, and the upper bearing 6a is fixed to the upper top surface portion 7a. Further, a lower bearing 6b having a symmetrical arrangement configuration with the upper bearing 6a is provided on the lower bottom surface portion 7b, and a pushing rod 10 facing the draw bar 9 is inserted into the lower bearing 6b. It is guided so as to be movable in the vertical direction that is the axial direction. In the upper and lower bearings 6a and 6b, a plurality of slits as relief grooves for the link mechanism 2 and pins 11a and 11b, which will be described later, are formed in the cylindrical portions.

  The specific structure of the link mechanism 2 is described as follows. As shown in the front view of FIG. 4 and the like, the link mechanism 2 is composed of a parallel two-plate structure (see FIG. 5) having an arcuate arc shape as a whole. Are connected to the cylinder rod 5 and the push rod 10, respectively. As a detailed configuration, as shown in FIG. 5, it is pivotally supported by pins 11a and 11b having the same shape arranged vertically, and these pins 11a and 11b are integrally fixed to the rods 5 and 10, respectively. Thus, the upper and lower ends of the two plates are concentrically connected. A rigid link mechanism 2 is configured by interposing a cam floor described later between the two plates. Accordingly, the link mechanism 2 is configured as a means capable of transmitting power from the first air cylinder 1 to the push rod 10 side by connecting the upper and lower ends to the rods 5 and 10.

  However, cylindrical cam floors 12a and 12b which are slidably contactable with the cam member 4 (details will be described later) are disposed between the two plates, and are arranged concentrically with the pins 11a and 11b. For example, it is rotatably mounted via a needle bearing (see FIG. 5), so that the upper and lower cam floors 12a and 12b function as means for directly receiving and transmitting displacement by the cam member 4, and as a result Specifically, it is also configured as a means capable of transmitting displacement to the push rod 10 side. However, as shown in FIG. 4 (or FIG. 1A), in the clamped state, a slight gap G (for example, between the lower end surface (cam surface 4a) of the cam member 4 and the peripheral surface of the lower cam floor 12b is used. , 0.1-0.2 mm).

  Next, the specific structure of the cam member 4 will be described with reference to FIGS. 4 and 5 and the front view shown in FIG. 2. The cam member 4 has a plate shape and is non-circular based on different radii on the peripheral side surface ( The cam surface 4a (when viewed from the front) is formed. First, the built-in configuration of the cam member 4 will be described. In particular, as disclosed in FIG. 5, the cam member 4 partially overlaps the inside of the concave side of the intermediate portion of the link mechanism 2 when viewed from the front (see FIG. 4). The cam surfaces 4a are interposed and supported by the upper cam floor 12a or the lower cam floor 12b based on the gap G so as to be slidable.

  With such an assembly structure of the link mechanism 2 and the cam member 4, as shown in the side view of FIG. 5, both are arranged on the same center line in the vertical direction, and further, the same with the one push rod 10 below the same. It becomes the structure connected on the centerline. As will be apparent from the description of the operation described later, the power from both the link mechanism 2 and the cam member 4 is accurately and effectively transmitted to one push rod 10 without being displaced. I am doing so.

  The cam member 4 has a shaft support structure in which ball bearings 14 and 15 in which cam shafts 13 penetrating the center in the horizontal direction and integrally connected and fixed are arranged at both left and right end portions in the main case 7. It is supported rotatably via However, the left end side (rear surface side) shown in FIG. 5 of the camshaft 13 extends out of the main case 7, and the cam member 4 is disposed at the large end portion (hereinafter referred to as the large-diameter shaft portion 13 a). Power transmission means (details will be described later) from the cam drive source are connected to rotate the cam member 4. The power transmission means provided so as to protrude outside the main case 7 is provided in an irregularly shaped drive case 16 covering the drive case according to the drive form, and the drive case 16 is provided in the main case 7. It is fixed on the rear side.

  In such a drive source of the cam member 4 and its power transmission means, the rotational power is applied to the large-diameter shaft portion 13a formed by extending the rear end portion of the cam shaft 13 as disclosed in FIGS. To be communicated. That is, a pinion 17 having, for example, spherical teeth is formed on the outer peripheral surface of the large diameter shaft portion 13a over 180 degrees. A rack 18 that linearly moves in the horizontal direction is engaged with the pinion 17 and is slidably accommodated in the drive case 16.

  A second air cylinder 19 composed of a double-acting air cylinder is provided as a cam drive source on one end side of the rack 18, and the rack 18 formed integrally therewith can be reciprocated to the left and right. . This reciprocation is executed in a range of 180 degrees where the spherical teeth of the pinion 17 are formed. The cylinder case 19c connected to the drive case 16 is formed with pressure chambers 19a and 19b, and the first and second functions as stoppers for restricting the displacement (stroke) of the second air cylinder 19. The step portions 20a and 20b are formed so as to protrude inward, and the reciprocating displacement of the air cylinder 19 is determined to ensure an effective stroke accurately.

  FIG. 3 shows the displacement of the cam member 4 in the axial direction with respect to the rotation angle, and discloses the stroke change formed by the so-called cam surface 4a. This will be described in detail in the description of the operation in conjunction with the cam function of the cam member 4 in FIG. 2. For example, from FIG. 3, while the cam member 4 rotates 180 degrees, the axial displacement is 11.5 in total. (Mm) can be understood. Reference symbols A, B, C, and D shown in the figure represent main operation points at a predetermined rotation angle along the rotation direction indicated by the arrow A of the cam member 4 shown in FIG. Are located on the center line of the cam member 4, of which points A and C, and points B and C are on the respective center lines and are in a relative positional relationship.

  Next, the configuration on the main shaft 3 side to which power is transmitted from the driving device 8 will be described with reference to FIG. 1A, for example. FIG. 1A shows an embodiment in which the main shaft 3 is provided directly below the drive device 8 and shows a state in which a tool holder 21 to which a tool (not shown) is mounted is clamped. The draw bar 9 provided so as to be movable is held at a position moved to the uppermost position. Specifically, the shaft hole 22 into which the draw bar 9 is inserted has holes of various diameters and penetrates in the vertical direction. An elastic member 23 made of a disc spring (or a coil spring or the like) is attached to the bottomed hole portion 22a in the upper half portion, and this elastic member 23 always urges the draw bar 9 inserted in the center upward. It is incorporated in a state where the resilience is accumulated.

  Then, in the so-called unclamped state (not shown) in which the draw bar 9 does not have a load such as the tool holder 21 or the like, the draw bar 9 is stopped by the small-diameter step portion 22b in the shaft hole 22 and beyond. It is configured to prevent the rise. Therefore, the draw bar 9 is configured to be stably held at a predetermined position in a state where the elastic force of the elastic member 23 is accumulated, that is, a state of being urged upward. On the other hand, as shown in FIG. 1A, even when the tool holder 21 is in a clamped state where the tool holder 21 is attached to the main shaft 3, the draw bar 9 is held in a state of being urged upward as described above. However, in this clamped state, priority is given to the tool holder 21 and the tapered hole portion 22e being fitted and firmly held by the collet chuck 24, which will be described later, so that the rise of the draw bar 9 is stopped by the stepped portion 22b. Previously regulated and held stable in that position.

  On the other hand, a known collet chuck 24 provided at the lower end of the draw bar 9 is provided in the lower half of the shaft hole 22. In the lower half portion of the shaft hole 22, a small-diameter hole portion 22c, a large-diameter hole portion 22d, and a tapered hole portion 22e are formed continuously downward. In the clamped state shown in FIG. 1A, the collet chuck 24 is pulled by the elastic member 23 and is in the raised position, which is the region of the small hole portion 22c. For this reason, the sphere of the collet chuck 24 is in an inward projecting state, the sphere is kept in engagement with the head of the tool holder 21, and the outer peripheral surface of the tool holder 21 is in the raised position. The tool holder 21 is stably held in a clamped state by fitting into the tapered hole 22c. In addition, the positional relationship which has the clearance gap S of a predetermined dimension (for example, 3.5 mm) is maintained between the upper end surface of the draw bar 9 in this clamp state, and the lower end surface of the said pushing rod 10 by the side of the drive device 8. Thus, the main shaft 3 side is maintained in a drivable state.

Next, the operation in the case of unclamping, for example, when changing the tool in the above configuration will be described.
First, the operation procedure of unclamping from the clamped state of FIG. 1A to the unclamped state shown in FIG. 1C through the intermediate process shown in FIG. 1B will be described. Among them, in the clamped state shown in FIG. 1A, the pressure chamber 1a of the first air cylinder 1 is continuously maintained in a predetermined pressure state, and the vertical downward movement power of the cylinder rod 5 based on the pressure chamber 1a is Then, it is transmitted to both of the cam members 4 via the link mechanism 2 and the upper cam floor 12a. However, the power is stopped by the cam member 4 that is still stopped, and therefore neither the link mechanism 2 nor the cam member 4 transmits power, and the drive device 8 has substantially the original function. Absent. As a result, there is no change on the main spindle 3 side where the tool is mounted, and the distance between the upper end surface of the draw bar 9 and the lower end surface of the lower rod 10 is an initial predetermined dimension (3.5 mm in this embodiment). The gap S is maintained.

  Thus, in the clamped state, the power of the first air cylinder 1 is received by the cam member 4, and the cam surface 4a is joined to the upper cam floor 12a at the point A on the center line shown in FIG. The point A has a cam surface 4a shape having a section a having the same radius in a range of, for example, ± 5 degrees (total 10 degrees) across the center line, and the other points B, C, and D are also the same. Have the same radius sections b, c and d.

Therefore, as shown in FIG. 3, at the point A where the cam member 4 is joined to the upper cam floor 12a, the rotation angle is 0 degree and the displacement of the push rod 10 is 0 (mm). A gap S of 5 (mm) exists. As described above, the point A shows the joint portion with the upper cam floor 12a in the stationary state of the cam member 4, but this is also the driving point at which the rotational driving is started when the cam member 4 is unclamped.
In the present embodiment, it is preferable that the upward biasing force of the draw bar 9 by the elastic member 23 in the clamped state is set to be equal to or slightly larger than the pressure of the first air cylinder 1. The air cylinder 1 can be easily variably set.

  Next, the state in which the cam member 4 is rotationally driven in the direction of the arrow A from the clamped state of FIG. 1A and reaches the intermediate process shown in FIG. 1B will be described. This is because, as shown in FIG. 6, when one pressure chamber 19a of the second air cylinder 19 which is the drive source of the cam member 4 is pressurized, the rack 18 is linearly moved in the direction of arrow B in the figure, and It is converted into a rotational motion via the pinion 17 and the cam member 4 is rotationally driven in the direction of arrow A shown in FIG.

  At the time of this rotational drive, the cam member 4 is initially in sliding contact only with the upper cam floor 12a side, and there is a gap G between the lower cam floor 12b, so that it can be smoothly rotated with a small driving force. it can. In addition, as shown in FIG. 2, the cam surface 4a moves in the direction of the point B, that is, the junction point with the upper cam floor 12a in the contact state, that is, gradually shifts to the smaller diameter side where the radius becomes smaller. Eventually, when the rotation angle reaches 105 degrees, the joint point with the upper cam floor 12a reaches the point B.

  Here, the partial shape of the cam surface 4a will be described. The diameter of the cam member 4 passing through the center (the axis of the cam shaft 13) is the same shape as the cam surface 4a. Accordingly, the radius of the point A of the cam surface 4a with which the upper cam floor 12a is in contact with the point B side gradually decreases, but the radius from the point C to D located on the opposite side is contrasted. The diameters are gradually increased and their diameter dimensions are always the same.

  In this way, when the cam member 4 is started and rotated to the smaller diameter side, the upper cam floor 12a in contact with the cam surface 4a is immediately moved downward because the power from the first air cylinder 1 is constantly received. To do. The link mechanism 2 that is pivotally supported in the same manner as the upper cam floor 12a also starts to move at the same time, and moves the push rod 10 downward. For this reason, the gap S (initial dimension 3.5 mm) at the upper end surface of the draw bar 9 is narrowed, and finally the lower end surface of the push rod 10 is joined to the upper end surface of the draw bar 9. That is, in this embodiment, the displacement is 3.5 (mm).

  This state is also apparent from FIG. That is, when the position of the above point B (the rotation angle of the cam member 4 is 105 degrees) from the point A on the upper cam floor 12a side is reached, strictly speaking, the rotation angle reaches a position of 100 degrees that is 5 degrees before. It can be seen that it has been displaced by 3.5 (mm) at the time. However, the load on the cam member 4 during the 3.5 (mm) displacement is only due to the power of the first air cylinder 1 that is constantly pressurized through the upper cam floor 12a on the upper end side. In addition, since the upper cam floor 12a is also rotatable, a large force is not required as a driving force for rotating the cam member 4.

  Thus, when the downward movement further proceeds after reaching the point B, the downward movement of the draw bar 9 is started, and this point B is also a branch point where the draw bar 9 switches from the stationary state to the moving state. It is also the starting point. However, since the vicinity of the point B is the cam surface 4a having the shape of the section b having the same radius within a slight rotation angle of 10 degrees as described above, the moving power to be lowered with respect to the draw bar 9 is substantially Does not work. That is, the same radius section b functions as a section in which the power transmission in the unclamping direction temporarily stops while the cam member 4 is rotationally driven.

  Thus, the cam surface 4a only rotates in a sliding state and does not perform the original cam function. Therefore, in this embodiment, the pushing rod 10 moves downward from the point A to B of the cam member 4 at the same ratio (indicated by a gentle linear gradient in FIG. 3), and the initial dimension of the gap S is 3.5 (mm). After moving, the same radius section b centering on the point B where the cam function is not achieved is reached, and the stationary state where the power transmission in the moving direction is temporarily stopped is maintained.

  This temporarily stopped state is that when the pushing rod 10 comes into contact with the upper end surface of the draw bar 9, it is stopped within the range of the above-mentioned rotation angle of 10 degrees without being rapidly moved downward. It acts to soften the shock at the time of contact, and works advantageously to suppress the mechanical strength and impact sound between the abutting. Accordingly, since the draw bar 9 does not move downward in this stationary state, the tool holder 21 by the collet chuck 24 is still in the clamped state shown in FIG. 1A on the main shaft 3 side.

  When the cam member 4 further rotates to the smaller diameter side (in the direction of arrow A) and passes through the same radius section b of the point B, the cam function is effective and the power from the first air cylinder 1 is linked to the link mechanism. The action of pressing the draw bar 9 downward through 2 etc. is started. However, since the upward biasing force by the elastic member 23 of the draw bar 9 is set to be equivalent to (or slightly larger than) the power of the cylinder means, this is generated as a load simultaneously with the start of the lowering of the draw bar 9, and the load is large. Therefore, the draw bar 9 cannot be pushed and moved only by the power of the first air cylinder 1 as it is.

  However, according to the present embodiment, after passing through the point B section, the cam surface 4a comes into sliding contact with the lower cam floor 12b side in accordance with the load utterance on the draw bar 9 side. The cam surface 4a presses the lower cam floor 12b, and the push rod 10 can be pressed down to move the draw bar 9 downward against its urging force. More specifically, first, the radius that forms the cam surface 4a that has been in sliding contact with the upper cam floor 12a side is gradually reduced, and the opposite radius tends to increase in contrast, and As described above, on the main shaft 3 side, the urging force in the direction of raising the draw bar 9 as a load tends to be gradually increased as it moves.

  For this reason, the gap G that exists and is formed in the lower part of the cam member 4 disappears, and the gap G is generated on the opposite upper cam floor 12a side (see FIG. 1B). Therefore, after that, the cam surface 4a comes into sliding contact with only the lower cam floor 12b, and as a rotational load on the cam member 4, an upward biasing force of the draw bar 9 is applied via the lower cam floor 12b. The biasing force tends to increase as the elastic member 23 is compressed.

  However, the power from the first air cylinder 1 in the constantly pressurized state acting in the direction opposite to the urging force is transmitted to the push rod 10 via the link mechanism 2 and acts to depress the draw bar 9. To do. As a result, the differential pressure between the opposing biasing force on the draw bar 9 side and the power on the first air cylinder 1 side (biasing force ≧ power) becomes a load on the cam member 4 to press the draw bar 9. Not too much. Therefore, the driving force for rotating the cam member 4 is small, and the cam member 4 can be rotated smoothly and rapidly. This is effective for executing the movement of the draw bar 9 at a high speed, and in particular, during the progress of the rotation angle of 75 degrees from point D to point A described later on the lower cam floor 12b side of FIG. A large movement of 8 (mm) (= 11.5−3.5 mm) can be quickly executed.

  Thus, thereafter, as the cam member 4 continues to rotate, the cam surface 4a in contact with the lower cam floor 12b as shown in FIG. 3 enables the cam surface 4a from the point D to the point A side as a cam function. A so-called radius rapidly proceeds to an operation section where the diameter is increased rapidly, and a cam function for pressing the lower cam floor 12b is exhibited. As a result, the power by the first cylinder 1 that is continuously driven and the power by the cam function of the cam member 4 are intensively transmitted to one push rod 10, and the push rod is subjected to the joint action. 10 rapidly descends and depresses the draw bar 9 against the urging force.

  Therefore, as apparent from the above, the rotational load of the cam member 4 can be reduced as compared with the case where the draw bar 9 is moved by the single function of the cam member 4, and the rotational driving force can also be reduced. Incidentally, in FIG. 1B which specifically shows this intermediate process, the main bar 3 side shows the initial lowered position where the draw bar 9 is slightly depressed, and the collet chuck 24 is still located in the small-diameter hole portion 22c, and the tool holder The state where 21 is held is shown.

  When the rotation of the cam member 4 further proceeds from the above state, the cam surface 4a in contact with the lower cam floor 12b reaches the point A, and the cam member 4 also stops rotating. In this state, as shown in FIG. 1C, the collet chuck 24 moves toward the large-diameter hole 22d and reaches an unclamped (possible) state, and the tool holder 21 can be removed. Further, FIG. 3 shows that the cam member 4 is moved in the 11.5 (mm) axial direction as a total movement displacement in the unclamping direction of the push rod 10 with respect to the rotation of 180 degrees as a whole. After the point B where the drawbar 9 actually starts to move, the displacement is 8.0 (mm) (= 11.5 mm-3.5 mm) with respect to the rotation angle of 75 degrees (= 180 degrees-105 degrees). ) It is moved in the axial direction. In addition, according to the present embodiment, it has been confirmed that the rotation angle of 180 degrees and the time required for the movement displacement of 11.5 (mm) can be instantaneously set to 0.2 seconds. To be able to run at speed.

  However, the position where the cam member 4 stops is effective not only for the power transmission means but also for setting a predetermined stop position of the cam member 4 by employing the rack means shown in FIG. In other words, in the present embodiment, the end of the second air cylinder 19 integral with the end of the rack 18 is stopped by the step 20b in the cylinder case 19c as shown by a two-dot chain line in the figure. The cam member 4 to which the rotational power is transmitted through the pinion 17 is stopped at a predetermined position, and the unclamped state shown in FIG. 1C is reached.

  As shown in FIGS. 2 and 3, the points A, B, C, and D of the cam member 4 have the same radius sections a, b, and c within a range of ± 5 degrees (total 10 degrees). , D, of which the section b is convenient for obtaining a buffering action on the draw bar 9 as described above, and in the other sections a, c, d, the cam member 4 and the upper and lower cam floors 12a, Although it is convenient to stably maintain the stopped state by joining with each of 12b, even if these are not necessarily provided, the downward movement of the draw bar 9 by the cam function can be executed at a high speed.

  On the other hand, when the case of the clamping operation is described, this can be executed substantially in the reverse procedure to the unclamping operation procedure. Accordingly, the cam member 4 is driven to rotate in the direction of the anti-arrow A which is the anti-unclamping direction. As shown in FIG. 6, the pressure chamber 19 b of the second air cylinder 19 is pressurized and the rack 18 is returned and moved in the counter-arrow B direction, thereby moving the cam member 4 through the pinion 17. It can be rotationally driven in the direction.

  Accordingly, the clamping operation is executed in the order shown in FIGS. 1C, 1B, and 1A in which the rotation direction of the cam member 4 is reversed. The load applied to the cam member 4 at the time of clamping may act as a negative load because the urging force in the direction in which the draw bar 9 returns tends to be equal to or better than the power on the first air cylinder 1 side. For example, the rotational driving force of the cam member 4 may be a small force that is extremely reduced, and can be rotated smoothly and rapidly. If necessary, it is possible to control the pressure of the first air cylinder 1 to be reduced. In this case, it can be expected that the rotation of the cam member 4 is made smoother.

According to the said Example, there exist the following effects.
When the link mechanism 2 capable of transmitting the power from the first air cylinder 1 constituting the drive device 8 to the draw bar 9 and the cam member 4 provided in parallel with the link mechanism 2 and unclamping the tool, The draw bar 9 is moved in the unclamping direction against the urging force based on the power transmission action of the first air cylinder 1 driven in the constantly pressurized state and the rotational drive of the cam member 4. Further, it is possible to provide an unclamping method in which the collet chuck 24 is moved to the large-diameter hole 22d side and the tool holder 21 can be detached.

  While this unclamping is being performed, when the draw bar 9 is pushed and moved against its urging force, naturally a large counter load is applied to the drive device 8 side. That is, the urging force of the draw bar 9 is applied as a particularly large load to the cam member 4 that is rotationally driven to transmit mechanical displacement as power to the draw bar 9. However, in this embodiment, the urging force of the draw bar 9 can be offset by the power from the first air cylinder 1 that is always pressurized, and a small force based on the differential pressure (biasing force) is a cam member. 4 is a load.

  As a result, the cam member 4 can be smoothly rotated with a small force, and the drawer bar 9 having a large urging force is reliably moved in the unclamping direction based on the mechanical displacement as the power from the cam member 4. Can be made. Moreover, the drive of the cam member 4 is effective in that accurate drive control can be performed, in addition to being capable of high speed control compared to cylinder means, etc., and the unclamping operation can be performed very quickly and extended. In addition, it can be expected to improve production efficiency.

In this embodiment, an air cylinder is used as a drive source, but this can be replaced by a hydraulic cylinder. However, the air cylinder is advantageous in that it can be installed relatively easily as a power facility as compared with a hydraulic cylinder and has excellent responsiveness. However, the unclamping means using only these cylinder means is unsuitable for drive control such as stopping accurately with a desired movement displacement (stroke). Loss will be incurred. However, in this embodiment, the movement displacement including the power from the cylinder means can be controlled by the cam member 4, and this is also effective in providing an accurate and high-speed unclamping method.
By doing so, it is possible to provide the drive device 8 with excellent response and simple configuration.

  The cam member 4 once stops the power from the first air cylinder 1 and then transmits the power to the draw bar 9 by the cooperative action of the link mechanism 2 and the cam member 4 as the cam member 4 rotates. As a result, the power from the first air cylinder 1 based on the constantly pressurized state can always be exhibited in a timely manner in accordance with the rotational drive of the cam member 4, and the unclamping operation can be performed accurately.

  The cam member 4 receives power from the first air cylinder 1 from above and receives a biasing force imposed on the draw bar 9 on the main shaft 3 side from below. And the lower cam floors 12a and 12b and a slight gap G (0.1 to 0.2 mm in the present embodiment) are present. There is no restraint.

  Further, the adoption of the cam member 4 is convenient for obtaining a mechanical displacement with excellent accuracy. On the other hand, while the cam member 4 is being driven to rotate, the displacement to the unclamp side is reduced to 0 (mm). It can be easily suppressed. That is, a region having the same radius that functions as a stop section may be formed on the cam surface 4a. Accordingly, at the point B where the draw bar 9 is started by receiving the power from the driving device 8 side as in this embodiment (see FIGS. 2 and 3), the stop section is in a slight range (10 degrees in total) of the cam surface 4a. Since the same radius section b is formed, it is possible to mitigate the impact caused by the contact when the power is transmitted to the draw bar 9, and it is effective for durability due to mechanical strength, reduction of impact sound, and the like. Therefore, even if the cam surface 4a is provided with an operation section for rapidly moving the draw bar 9 after passing through the stop section, the draw bar 9 can be smoothly moved down without worrying about an impact sound or the like.

  The cam drive source of the cam member 4 is not limited to the second air cylinder 19, and a motor or the like can be used as the drive source. However, according to the configuration in which the power from the second air cylinder 19 is converted into the rotational motion by the pinion 17 from the rack 18 that linearly moves as in the present embodiment, the rotational drive is performed by the servo motor. Compared with the case where it carries out, it has the advantage that it can provide cheaply and can set the regulation displacement corresponding to the required rotation angle of the cam member 4 easily.

(Second Embodiment)
FIG. 7 is a view corresponding to FIG. 1A showing the second embodiment of the present invention. In the following, the same parts as those in the above embodiments are denoted by the same reference numerals and the description thereof will be omitted, and different parts will be described. In this embodiment, the main shaft 3 having the draw bar 9 is arranged immediately below the drive device 8 having the first air cylinder 1 and the cam member 4 in the above embodiment, whereas the main shaft 3 side is driven, for example. The present invention provides a tool unclamping method in a machine tool that is suitable for a case where the arrangement configuration is shifted laterally from directly below the apparatus 8.

  The feature is that the first air cylinder 1, the link mechanism 2, and the drive device 8 side including the cam member 4 provided in parallel with the link mechanism 2, the main shaft 3 side on which the tool is mounted, In between, the cylinder transmission means which enables transmission of power in different directions is interposed. That is, the hydraulic cylinder device 25 is disposed as a cylinder transmission means to transmit power from the link mechanism 2 and the cam member 4 on the drive device 8 side via the lower cam floor 12b. The displacement displacement as a power can be easily transmitted to the draw bar 9 of the main shaft 3, and the draw bar 9 can be moved in the axial direction of the unclamping direction so that it can be widely applied to installation conditions.

  However, as a basic configuration of the hydraulic cylinder device 25, as shown in the figure, a first hydraulic cylinder 26 that receives and cooperates with the power from both the link mechanism 2 and the lower cam floor 12b is provided on the main case 7 side. On the other hand, a second hydraulic cylinder 27 is provided immediately above the main shaft 3 side, and the cylinders 26 and 27 are connected by a cylinder pipe 28. Accordingly, when the pressure chamber 26a of the first hydraulic cylinder 26 is pressurized by receiving power from the link mechanism 2 and the cam member 4, the hydraulic pressure is immediately transmitted to the second hydraulic cylinder 27 side via the cylinder pipe 28. The cylinder rod 29 is pushed downward.

  As a result, the cylinder rod 29 can move the opposing draw bar 9 downward, and the so-called cylinder rod 29 functions as a push rod. Incidentally, the push rod 10 in the first embodiment is provided on the drive device 8 side, whereas the cylinder rod 29 (push rod) in the present embodiment is disposed on the main shaft 3 side that is largely separated. The power from the link mechanism 2 and the cam member 4 is intensively transmitted to the cylinder rod 29 as in the first embodiment.

  An elastic contact mechanism 30 composed of a sphere and a coil spring is provided on the side of the cylinder rod 29, and is fitted in a state of being elastically pressed into a longitudinal (vertical) groove on the cylinder rod 29 side. . Thereby, the elastic contact mechanism 30 functions as an unnecessary rotation stop of the cylinder rod 29 and also has a function of urging the cylinder rod 29 to rise by the reaction of the spring during clamping.

  According to the said structure, it exists in the structure which interposed the hydraulic cylinder apparatus 25 which is a cylinder transmission means in order to transmit motive power between the main shafts 3 large spaced apart from the drive device 8. FIG. However, it differs from the above-described embodiment in that a cylinder transmission means is interposed, but the function of performing unclamping is substantially the same. That is, when the cam member 4 is rotationally driven in the direction of the arrow A and the downward power in the unclamping direction is transmitted to the lower cam floor 12b, the hydraulic pressure of the pressure chamber 26a is increased, and the main shaft 3 side via the cylinder pipe 28 Supplyed to the second hydraulic cylinder 27. Accordingly, the cylinder rod 29 is pushed down against the pressure contact force of the elastic contact mechanism 30, and the draw bar 9 positioned immediately below is pushed down against the urging force of the elastic member 23. The tool holder 21 can be removed.

  On the other hand, when the tool is clamped, it is performed along the reverse operation procedure as in the above embodiment. That is, when the cam member 4 is rotationally driven in the direction of the arrow B, first, the pressurized state to the first hydraulic cylinder 26 is released, and thus the unloaded state is reached. Along with this, the urging force by the elastic member 23 of the draw bar 9 on the main shaft 3 side is won, and the cylinder rod 29 that has been in the pressure contact state is lifted, and the draw bar 9 is raised to the initial predetermined position. Then, after the draw bar 9 stops at a predetermined position, the cylinder rod 29 in a substantially unloaded state is advanced in the upward direction by the reaction action (elastic force) of the elastic contact mechanism 30, and the return movement is advanced. It rises to a position having a predetermined gap S (3.5 mm in the embodiment) between the rod 29 and the draw bar 9, reaches a clamp state shown in the figure, and stops.

  As described above, according to the second embodiment, when the tool is unclamped, the draw bar can be moved at high speed with an accurate and small force in the same manner as the first embodiment. Even if the main spindle 3 on the side is displaced laterally as shown in the figure, power is transmitted via the hydraulic cylinder device 25 as cylinder transmission means, and unclamping is performed quickly without any trouble. It has features that can. In this case, even if the cylinder pipe 28 is flexible or rigid, it can be easily connected to the displaced main shaft 3 side by forming it in a desired form in advance. .

  Therefore, this cylinder transmission means exhibits the function of changing the direction of the power on the drive device 8 side via the cylinder transmission means. The cylinder transmission means is not limited to the above-described positional deviation, but is directly below the drive device 8, for example. There are various arrangement conditions such as the arrangement condition in which the main shaft 3 positioned at a distance from the main shaft 3 is greatly separated, or the main shaft 3 that moves downward in a different direction from the horizontal direction. A practical effect that can meet the installation conditions can be expected.

  The present invention is not limited to the embodiment described above and shown in the drawings. For example, the link mechanism is not limited to a two-plate configuration, and a single-plate configuration is possible. The present invention can be implemented with various modifications without departing from the gist of the present invention.

1 is a longitudinal front view showing a first embodiment of the present invention. FIG. 1A equivalent diagram showing different operating states Furthermore, FIG. Front view of cam member Explanatory drawing of action accompanying drive of cam member Enlarged view of the main part of FIG. 1A Left side view of FIG. Rear view of FIG. FIG. 1A equivalent view showing a second embodiment of the present invention

Explanation of symbols

  In the drawings, 1 is a first air cylinder (cylinder means), 2 is a link mechanism, 3 is a main shaft, 4 is a cam member, 8 is a drive device, 9 is a draw bar, 10 is a push rod, 12a and 12b are up and down Cam floor, 17 is a pinion, 18 is a rack, 19 is a second air cylinder (cam drive source), 21 is a tool holder, 23 is an elastic member, 24 is a collet chuck, 25 is a hydraulic cylinder device (cylinder transmission means), And 28 indicate cylinder pipes.

Claims (7)

By unclamping the tool attached to the spindle by moving the draw bar in the spindle in the axial direction,
The draw bar is biased in the clamping direction by the elastic force of an elastic member, and includes a driving device that moves the draw bar in the unclamping direction against the biasing force.
The drive device includes cylinder means, a link mechanism capable of transmitting power from the cylinder means to the draw bar, and a cam member provided in parallel with the link mechanism.
A method for unclamping a tool in a machine tool, wherein the draw bar is moved in an unclamping direction based on both the normal pressure applied by the cylinder means and the power transmission action accompanying the rotational driving of the cam member.   The cam member temporarily interrupts the power from the cylinder means and then transmits the power to the draw bar by the joint action of the link mechanism and the cam member as the cam member rotates. Item 2. A method for unclamping a tool in the machine tool according to Item 1.   3. The unclamping of a tool in a machine tool according to claim 2, wherein the cam member is inserted with a slight gap between the cam floors respectively provided on the upper and lower sides of the cam member. Method.   On the cam surface of the cam member, when power in the unclamping direction is transmitted to the draw bar by the rotational drive of the cam member, a stop section having substantially the same radius is provided to temporarily stop the start of the draw bar. 4. The method of unclamping a tool in a machine tool according to claim 2, wherein the tool unclamping method is provided.   5. The unclamping method for a tool in a machine tool according to claim 4, wherein the cam surface has an operation section for rapidly moving the draw bar after passing through the stop section.   6. The cam member according to any one of claims 1 to 5, wherein power from a cam drive source is converted into rotational motion from rack means that linearly moves and is transmitted and rotated. Tool unclamping method for machine tools in Japan.   7. The method for unclamping a tool in a machine tool according to claim 1, wherein the power from the drive device is transmitted to the draw bar via the cylinder transmission means and moved.

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