Diaphragm-type chuck device and workpiece fixing device

Abstract

In order to perform an opening and closing operation by means of a toggle mechanism (20), a diaphragm-type chuck device (200) has chuck claws (270) that open and close in accordance with the movement of an intermediate sleeve (25) disposed along the direction of a central axis C of a main shaft (10), and is attachable to and detachable from the main shaft (10), the toggle mechanism moving the intermediate sleeve (25) in the front-rear direction along the direction of the central axis C.

Description

Diaphragm type chuck device and workpiece fixing device

[0001] The present invention relates to a diaphragm type chuck device, and more particularly to a diaphragm type chuck device that is opened and closed by a toggle mechanism.

[0002] Machine tools such as lathes are equipped with a chuck device in order to fix a workpiece (hereinafter referred to as a workpiece), such as a round bar, to the spindle. As the chuck device, a collet chuck device (for example, see Patent Document 1) and a diaphragm type chuck device are known (for example, see Patent Document 2).

[0003] Japanese Patent Application Laid-Open No. 2002-066815, Japanese Patent Application Laid-Open No. 2008-188728

[0004] The collet chuck device is usually combined with a toggle mechanism. The toggle mechanism includes a bobbin, a chuck operating claw, and an intermediate sleeve. The bobbin is arranged behind the spindle with respect to the collet chuck and is movable along the axial direction of the spindle. One end of the chuck operating claw pivots between a state where it rides on the outer peripheral surface of the axially moving bobbin and a state where it does not ride on it. The intermediate sleeve is arranged inside the spindle along the axial direction of the spindle.

[0005] Then, the toggle mechanism moves the bobbin along the axial direction of the spindle by the driving force of an external driving lever. When the bobbin moves along the axial direction, one end of the chuck operating claw rides on the outer peripheral surface of the bobbin and pivots. By the swinging of the chuck operating claw, the other end of the chuck operating claw pushes the rear end of the intermediate sleeve forward in the direction of the front of the spindle. The intermediate sleeve pushed forward is displaced forward along the axial direction of the spindle, and the front end of the intermediate sleeve moves the chuck sleeve of the collet chuck device forward. When the chuck sleeve moves forward, the collet arranged on the inner peripheral side of the chuck sleeve is pushed in the direction of the center in the radial direction of the spindle, the inner diameter of the collet becomes smaller, and the collet grips and fixes the workpiece.

[0006] On the other hand, diaphragm-type chuck devices are usually combined with a fluid supply device, such as air. The fluid supply device supplies fluid, which displaces a piston located on the back side of the diaphragm toward the front of the spindle, causing the diaphragm to elastically deform and open the chuck jaws provided on the diaphragm.

[0007] Thus, collet chuck devices and diaphragm-type chuck devices differ significantly in the mechanisms for opening and closing the chuck. For this reason, collet chuck devices are generally configured as dedicated machines assembled to the spindle along with a toggle mechanism, while diaphragm-type chuck devices are generally configured as dedicated machines assembled to the spindle along with a fluid supply device.

[0008] Depending on the required machining accuracy when processing a workpiece, there are cases where a collet chuck device is preferred and cases where a diaphragm-type chuck device is preferred. For example, when machining workpieces that require high machining accuracy, such as when the front spindle and rear spindle are arranged coaxially, there is a demand for a diaphragm-type chuck device that can fix the workpiece with higher precision than a collet chuck device.

[0009] However, as mentioned above, replacing a collet chuck device with a diaphragm-type chuck device requires a large-scale replacement, including the spindle, which presents a problem as it requires a great deal of labor.

[0010] The present invention has been made in view of the above circumstances, and aims to provide a diaphragm-type chuck device that can be opened and closed by a toggle mechanism.

[0011] The present invention relates to a diaphragm-type chuck device that has a toggle mechanism which moves an intermediate sleeve, positioned along the axial direction of the main spindle, in a forward and backward direction along the axial direction, and chuck jaws that open and close in accordance with the movement of the intermediate sleeve, and is detachably attached to the main spindle.

[0012] The diaphragm-type chuck device according to the present invention can be opened and closed by a toggle mechanism. As a result, in a spindle equipped with a collet chuck device that is opened and closed by a toggle mechanism, the collet chuck device according to the present invention can be replaced with the diaphragm-type chuck device without replacing the spindle or the toggle mechanism, thereby reducing the labor required for replacement work.

[0013] Figure 3A is a cross-sectional view of a workpiece fixing device equipped with a collet chuck, showing a cross-section along a plane containing the central axis C of the spindle, with the collet closed. Figure 4 is a cross-sectional view of a workpiece fixing device equipped with a diaphragm-type chuck, showing a cross-section along a plane containing the central axis C of the spindle, with the chuck jaws closed. Figure 5 is an enlarged view of the diaphragm-type chuck in Figure 2A. Figure 6 is a cross-sectional view of a workpiece fixing device equipped with a diaphragm-type chuck, showing a cross-section along a plane containing the central axis C of the spindle, with the chuck jaws open. Figure 7 is an enlarged view of the diaphragm-type chuck in Figure 3A. Figure 8 is an enlarged view equivalent to Figure 2B showing a cross-section along a plane containing the central axis C of the spindle, with the chuck jaws closed. Figure 9 is an enlarged view equivalent to Figure 3B showing a cross-section along a plane containing the central axis C of the spindle, with the chuck jaws open. This is an enlarged cross-sectional view of a workpiece fixing device equipped with a diaphragm-type chuck, taken from a plane including the central axis C of the main spindle, showing the chuck jaws in the open position. This is an enlarged cross-sectional view of a workpiece fixing device equipped with a diaphragm-type chuck, taken from a plane including the central axis C of the main spindle, showing the chuck jaws closed and gripping the workpiece W. This is an enlarged cross-sectional view of a workpiece fixing device equipped with a diaphragm-type chuck, taken from a plane including the central axis C of the main spindle, showing the chuck jaws open and discharging the workpiece W. This is a preferred modified example of the diaphragm-type chuck device shown in Figures 6A to 6C, and is an enlarged cross-sectional view of a key part corresponding to Figure 6A, showing the chuck jaws in the open position. This shows an enlarged view of the workpiece receiving component in the diaphragm-type chuck device shown in Figure 7A. This is an enlarged cross-sectional view of a key part corresponding to Figure 6B, showing the chuck jaws closed and gripping the workpiece W in the diaphragm-type chuck device shown in Figure 7A. This is an enlarged view of the main part, corresponding to Figure 6C, showing the diaphragm-type chuck device shown in Figure 7A with the chuck jaws open and the workpiece W discharged.

[0014] An embodiment of the diaphragm-type chuck device according to the present invention will be described below with reference to the drawings.

[0015] [Embodiment 1] Figure 1 is a cross-sectional view of a workpiece fixing device 300 equipped with a collet chuck device 100, showing a cross-section along a plane including the central axis C of the spindle 10, and showing the collet 120 in a closed state. Figure 2A is a cross-sectional view of a workpiece fixing device 400 equipped with a diaphragm-type chuck device 200, showing a cross-section along a plane including the central axis C of the spindle 10, and showing the chuck jaws 270 in a closed state. Figure 2B is an enlarged view of the diaphragm-type chuck device 200 in Figure 2A. Figure 3A is a cross-sectional view of the workpiece fixing device 400, showing a cross-section along a plane including the central axis C of the spindle 10, and showing the chuck jaws 270 in an open state. Figure 3B is an enlarged view of the diaphragm-type chuck device 200 in Figure 3A. The diaphragm-type chuck device 200 is one embodiment (Embodiment 1) of the diaphragm-type chuck device according to the present invention.

[0016] <Configuration of the workpiece fixing device 300> The workpiece fixing device 300 shown in Figure 1 has a collet chuck device 100 provided at the front end 10a of the spindle 10, and a toggle mechanism 20 provided at the rear end 10b of the spindle 10.

[0017] (Toggle mechanism) The toggle mechanism 20 moves in the forward and backward direction of the spindle 10 along the central axis C direction (axial direction) of the spindle 10, thereby opening and closing the collet chuck device 100. The toggle mechanism 20 comprises a bobbin 21, a chuck operating jaw 23, a chuck force adjustment nut 24, and an intermediate sleeve 25.

[0018] The bobbin 21 moves back and forth along the central axis C on the outer circumferential surface of the rear end 10b of the main spindle 10 by an external drive lever (not shown). The bobbin 21 is, for example, a radial ball bearing and comprises an inner ring 21b, an outer ring 21a, and balls. The inner ring 21b is loosely fitted to the outside of the outer circumferential surface of the main spindle 10 and can slide back and forth along the central axis C on the outer circumferential surface of the main spindle 10. The inner ring 21b is formed to extend further behind the central axis C than the outer ring 21a, and the rear end of the inner ring 21b is formed in a tapered shape with the outer circumferential surface inclined toward the rear edge.

[0019] The outer ring 21a is positioned on the outside of the inner ring 21b via a plurality of balls. The inner ring 21b and the outer ring 21a can rotate relative to each other around the central axis C via the balls. The aforementioned drive lever engages with the outer ring 21a. When the drive lever moves the outer ring 21a back and forth along the central axis C, the inner ring 21b slides back and forth along the central axis C via the balls, and the bobbin 21 moves back and forth along the central axis C.

[0020] The chuck jaws 23 are located at the rear of the bobbin 21 along the central axis C, and there are two of them arranged around the central axis C. The chuck jaws 23 are rotatable around the center D. When the bobbin 21 moves from the state shown by the dashed line in Figure 1 to the state shown by the solid line, moving rearward along the central axis C, one end 23a of the chuck jaws 23 rides up onto the outer surface of the inner ring 21b along the taper of the inner ring 21b. As a result, the chuck jaws 23 rotate (swivel) slightly around the center D, and the other end 23b of the chuck jaws 23 is displaced forward of the central axis C.

[0021] The intermediate sleeve 25 is provided inside the main spindle 10, along the central axis C. The intermediate sleeve 25 is biased toward the rear of the central axis C by the elastic force of the compression coil spring 140 of the collet chuck device 100, which will be described later. The rear end 25b of the intermediate sleeve 25 along the central axis C is always in contact with the other end 23b of the chuck jaws 23 from the front. Therefore, when the chuck jaws 23 rotate by the above-described operation, the other end 23b of the chuck jaws 23 pushes the rear end 25b of the intermediate sleeve 25 forward along the central axis C, causing the intermediate sleeve 25 to move forward along the central axis C against the biasing force of the compression coil spring 140.

[0022] Meanwhile, the drive lever moves the outer ring 21a forward along the central axis C, causing the bobbin 21 to move forward along the central axis C, and the inner ring 21b moves forward away from the position of one end 23a of the chuck jaw 23. As a result, one end 23a of the chuck jaw 23 moves from the outer surface of the inner ring 21b to the outer surface of the spindle 10, causing the chuck jaw 23 to pivot around the center D, and the other end 23b of the chuck jaw 23 moves backward along the central axis C. With the rear end 25b of the intermediate sleeve 25 still in contact with the other end 23b of the chuck jaw 23, the elastic force of the compression coil spring 140 causes it to move behind the central axis C.

[0023] (Collet chuck device 100) The collet chuck device 100, provided at the front end 10a of the main spindle 10, opens and closes in accordance with the movement of the intermediate sleeve 25 in the front-rear direction. The collet chuck device 100 comprises a collet 120, a chuck sleeve 110, a compression coil spring 140, and a cap nut 130.

[0024] The collet 120 is provided on the inside of the front end 10a of the main spindle 10, extending in the direction of the central axis C. The collet 120 abuts against a cap nut 130 fixed to the main spindle 10, preventing it from being displaced forward. The collet 120 has multiple slots formed in the circumferential direction around the central axis C. Due to these slots, the collet 120 flexes and expands and contracts radially around the central axis C. The outer circumferential surface of the collet 120 has a tapered shape that gradually increases in diameter towards the front end.

[0025] When the collet 120 is expanded radially, it allows the insertion of the workpiece to be gripped into the radially inward direction. When the collet 120 is contracted radially, it secures the inserted workpiece by gripping it from the radially outward direction.

[0026] The chuck sleeve 110 is provided inside the front end 10a of the spindle 10 and radially outside the collet 120, extending in the direction of the central axis C. The inner circumferential surface of the front end of the chuck sleeve 110 has a taper that contacts the taper formed on the outer circumferential surface of the collet 120. The chuck sleeve 110 is displaceable back and forth along the central axis C.

[0027] A keyway 110c is formed on a portion of the outer surface of the chuck sleeve 110 in the circumferential direction, extending parallel to the central axis C. A key pin 26, provided on a specific portion of the spindle 10 in the circumferential direction, is inserted into the keyway 110c. With the key pin 26 inserted into the keyway 110c, the chuck sleeve 110 becomes movable relative to the spindle 10 in the direction of the central axis C, and becomes an integral part of the spindle 10 in the circumferential direction around the central axis C.

[0028] As will be described later, when the collet 120 is gripping and fixing the workpiece, the collet 120 and the chuck sleeve 110 become one unit due to the frictional force between their tapered surfaces that are in contact with each other. Therefore, when the spindle 10 is rotating, the workpiece fixed to the collet 120 also rotates together with the spindle 10, and when the spindle 10 is stopped, the workpiece fixed to the collet 120 also stops together with the spindle 10.

[0029] When the chuck sleeve 110 is displaced forward, the taper of the chuck sleeve 110 presses against the taper of the collet 120 in a direction perpendicular to the taper. Since the forward displacement of the collet 120 is prevented, it grips the workpiece by elastically deforming in response to the pressing force acting on the taper, causing its inner diameter to shrink toward the central axis C.

[0030] When the chuck sleeve 110 returns to its rearward position before being displaced forward, the pressing force acting on the taper of the collet 120 disappears, and the elastic force restoring the elastic deformation of the collet 120 causes the collet 120 to expand its inner diameter back to its original size, releasing the grip on the workpiece.

[0031] The cap nut 130 is provided on the front end 10a of the spindle 10. A screw groove is formed on the inner circumferential surface of the cap nut 130, and this screw groove is screwed into a screw groove formed on the outer circumferential surface of the spindle 10 from the front, thereby fixing the cap nut 130 to the spindle 10. The cap nut 130 is positioned in contact with the front end of the collet 120, restricting the forward displacement of the collet 120. A gap is provided between the cap nut 130 and the front end of the chuck sleeve 110, allowing the chuck sleeve 110 to be displaced forward.

[0032] The compression coil spring 140 is positioned inside the chuck sleeve 110, extending in the direction of the central axis C. When the compression coil spring 140 is compressed from its natural length, its front end is in contact with the collet 120 and its rear end is in contact with the chuck sleeve 110.

[0033] Thus, the elastic force of the compression coil spring 140 acts as a biasing force that separates the chuck sleeve 110 and the collet 120 from each other along the central axis C. However, since the collet 120's forward displacement is restricted by the cap nut 130, the chuck sleeve 110 is constantly subjected to a biasing force that displaces it backward. As a result, the rear end 110b of the chuck sleeve 110 is always in contact with the front end 25a of the intermediate sleeve 25.

[0034] With the cap nut 130 fixed to the spindle 10, the chuck sleeve 110, collet 120, and compression coil spring 140 are housed inside the spindle 10. By loosening the screw thread of the cap nut 130 to the spindle 10 and removing the cap nut 130 from the spindle 10, the chuck sleeve 110, collet 120, and compression coil spring 140 can be removed from the front end 110a of the spindle 10. Therefore, the collet chuck device 100 is detachable from the spindle 10, which is equipped with the toggle mechanism 20.

[0035] The chuck force adjustment nut 24 is located behind the chuck operating jaws 23. A screw groove is formed on the inner circumferential surface of the chuck force adjustment nut 24, and this screw groove is screwed into a screw groove formed on the outer circumferential surface of the main spindle 10 from the rear.

[0036] When the chuck force adjustment nut 24 is screwed in, moving the chuck force adjustment nut 24 forward relative to the spindle 10 causes the entire toggle mechanism 20 to move forward relative to the spindle 10, and when the chuck force adjustment nut 24 is moved backward relative to the spindle 10, the entire toggle mechanism 20 moves backward relative to the spindle 10.

[0037] <Operation> In the workpiece fixing device 300, in which the collet chuck device 100 is attached to the spindle 10, when the toggle mechanism 20 is operated, the intermediate sleeve 25 moves forward (see Figure 1), and the chuck sleeve 110 in contact with the intermediate sleeve 25 is displaced forward against the elastic force of the compression coil spring 140, causing the collet 120 to contract in diameter and close, gripping and fixing the workpiece placed inside the collet 120 from the outside.

[0038] On the other hand, when the intermediate sleeve 25 moves backward from the state shown in Figure 1 by operating the toggle mechanism 20 of the workpiece fixing device 300, the chuck sleeve 110 is displaced backward in accordance with the backward movement of the intermediate sleeve 25 due to the elastic force of the compression coil spring 140 and the elastic force of the collet 120, causing the collet 120 to expand in diameter and open, releasing the grip on the workpiece.

[0039] In this way, the collet chuck device 100 grips and fixes the workpiece by opening and closing the collet 120.

[0040] Furthermore, by moving the chuck force adjustment nut 24 forward relative to the spindle 10, the entire toggle mechanism 20 moves forward relative to the spindle 10, causing the chuck sleeve 110 to move forward relative to the collet 120, thereby increasing the chuck force (fixing force) for gripping the workpiece.

[0041] On the other hand, when the chuck force adjustment nut 24 is moved backward with respect to the spindle 10 and the entire toggle mechanism 20 is moved backward with respect to the spindle 10, the chuck sleeve 110 moves backward with respect to the collet 120, so that the chuck force (fixing force) for gripping the workpiece can be reduced.

[0042] Thus, the toggle mechanism 20 can increase or decrease the chuck force on the workpiece by the chuck force adjustment nut 24.

[0043] <Configuration of Workpiece Fixing Device 400> The workpiece fixing device 400 shown in FIG. 2A has a configuration in which the collet chuck device 100 is removed from the spindle 10 of the workpiece fixing device 300 described above, and the diaphragm-type chuck device 200 shown in FIG. 2B is attached to the spindle 10. That is, the workpiece fixing device 400 is configured such that the diaphragm-type chuck device 200 is provided at the front end portion 10a of the spindle 10 extending along the central axis C, and the toggle mechanism 20 is provided at the rear end portion 10b of the spindle 10.

[0044] The diaphragm-type chuck device 200 opens and closes the chuck jaws 270 in response to the forward and backward movement of the intermediate sleeve 25. The diaphragm-type chuck device 200 is detachable from the spindle 10 provided with the toggle mechanism 20. Therefore, the spindle 10 provided with the toggle mechanism 20 can be provided with either the collet chuck device 100 or the diaphragm-type chuck device 200.

[0045] The configuration in which the collet chuck device 100 is attached to the spindle 10 provided with the toggle mechanism 20 is the workpiece fixing device 300, and the configuration in which the diaphragm-type chuck device 200 is attached to the spindle 10 provided with the toggle mechanism 20 is the workpiece fixing device 400.

[0046] (Diaphragm-Type Chuck Device 200) As shown in FIGS. 2A and 2B, the diaphragm-type chuck device 200 provided at the front end portion 10a of the spindle 10 includes a push rod 210, an adapter 220, a cap nut 230, a compression coil spring 240, a flange 250, a diaphragm 260, and chuck jaws 270.

[0047] The adapter 220 is provided inside the front end portion 10a of the main shaft 10 and extends in the direction of the central axis C. The adapter 220 abuts against the cap nut 230 fixed to the main shaft 10, preventing its forward displacement. A key groove 220c extending parallel to the central axis C is formed in a part of the outer peripheral surface of the adapter 220 in the circumferential direction. A key pin 26 provided in a specific part of the circumferential direction of the main shaft 10 is inserted into the key groove 220c. When the key pin 26 is inserted into the key groove 220c, the main shaft 10 and the adapter 220 are integrated in the circumferential direction around the central axis C. Further, the adapter 220 can be removed forward with respect to the main shaft 10 along the central axis C.

[0048] The push rod 210 is provided inside the adapter 220 and extends in the direction of the central axis C. The push rod 210 is movable back and forth in accordance with the back-and-forth movement of the intermediate sleeve 25. The rear end portion 210b of the push rod 210 is disposed behind the rear end of the adapter 220, and the front end portion 210a protrudes forward from the front end of the adapter 220.

[0049] The cap nut 230 holds the adapter 220 and the push rod 210 in a state where they are disposed inside the main shaft 10. The cap nut 230 is provided at the front end portion 10a of the main shaft 10. A screw groove is formed on the inner peripheral surface of the cap nut 230. By screwing this screw groove into the screw groove formed on the outer peripheral surface of the main shaft 10 from the front, the cap nut 230 is fixed to the main shaft 10. The cap nut 230 is disposed in contact with the front end of the adapter 220, restricting the forward displacement of the adapter 220. The cap nut 230 allows the forward displacement of the push rod 210 that protrudes forward of the cap nut 230 and the adapter 220.

[0050] The compression coil spring 240 is disposed inside the adapter 220 and extends in the direction of the central axis C. The compression coil spring 240 is disposed in a state where it is compressed from its natural length, with its front end in contact with the adapter 220 and its rear end in contact with the push rod 210.

[0051] Thus, the elastic force of the compression coil spring 240 acts as a biasing force that pushes the adapter 220 and the push rod 210 away from each other along the central axis C. Here, since the forward displacement of the adapter 220 is restricted by the cap nut 230, the push rod 210 is always subjected to a biasing force directed backward. As a result, the rear end 210b of the push rod 210 is always in contact with the front end 25a of the intermediate sleeve 25.

[0052] With the cap nut 230 fixed to the spindle 10, the push rod 210, the compression coil spring 240, and the adapter 220 are housed inside the spindle 10. By loosening the screw thread of the cap nut 230 to the spindle 10 and removing the cap nut 230 from the spindle 10, the push rod 210, the adapter 220, and the compression coil spring 240 can be removed forward from the front end 10a of the spindle 10.

[0053] The flange 250 is formed in a disc shape with a through hole in its center. The flange 250 is positioned in front of the cap nut 230 and is fastened and secured to the adapter 220 by bolts 282. The adapter 220 and flange 250 function as a base for fixing the diaphragm 260 to the spindle 10.

[0054] The outer diameter of the flange 250 is larger than the outer diameter of the front end 10a of the main spindle 10. Specifically, the flange 250 is formed with an outer shape that protrudes radially from the front end 10a of the main spindle 10. The large outer diameter of the flange 250 allows the position where the diaphragm 260, described later, is fixed to the flange 250 to be a position far to the outside from the central axis C. This ensures a large amount of elastic deformation of the diaphragm 260, and allows for a larger opening and closing stroke of the chuck jaws 270.

[0055] The through-hole formed in the center of the flange 250 is sized to allow the front end 210a of the push rod 210, which has passed through the cap nut 230, to pass through. This allows the front end 210a of the push rod 210 to pass through the through-hole in the flange 250.

[0056] The diaphragm 260 is positioned in front of the flange 250. The diaphragm 260 is formed in a short cylindrical shape with a bottom plate perpendicular to the central axis C. At the center of the end plate portion 263 which forms the bottom plate, an inner circumferential wall portion 262 (inner circumferential portion), which is a boss portion concentric with the outer circumferential wall portion 261 (outer circumferential portion) of the cylinder, is formed. The diaphragm 260 is fixed to the flange 250 by fastening the outer circumferential wall portion 261 to the radially outer portion of the flange 250 with bolts 281. The diaphragm 260 can be removed from the flange 250 by removing the bolts 281, and the diaphragm 260 is detachably attached to the flange 250.

[0057] The diaphragm-type chuck device 200 has an integrated structure consisting of an adapter 220, a flange 250, and a diaphragm 260, and the cap nut 230 is rotatably held in place. It can be attached to and detached integrally with the spindle 10.

[0058] Therefore, the diaphragm-type chuck device 200 can be attached and detached integrally to the spindle 10, which is equipped with the toggle mechanism 20, without having to disassemble the adapter 220, flange 250, diaphragm 260, and cap nut 230 from one another.

[0059] Furthermore, in the diaphragm-type chuck device 200, the key pin 26 of the spindle 10 is inserted into the keyway 220c of the adapter 220, allowing the chuck jaws 270, which are integrated with the adapter 220, to be fixed in a predetermined phase relative to the spindle 10 on a circumference of a certain radius centered on the central axis C. Therefore, the diaphragm-type chuck device 200, with its chuck jaws 270 positioned in a predetermined phase relationship with the spindle 10, can machine workpieces with polygonal or irregularly shaped cross-sections while following the phase of the workpiece around the central axis C, thereby achieving highly accurate machining.

[0060] The inner circumferential wall portion 262 of the diaphragm 260 is formed with a diameter approximately the same as the diameter of the front end portion 210a of the push rod 210. The diameter of the inner circumferential wall portion 262 should be such that, as shown in Figures 3A and 3B, when the push rod 210 is displaced forward, the end face (front end face) 210c of the front end portion 210a that has passed through the through hole in the flange 250 abuts against the rear end face 262b of the inner circumferential wall portion 262, thereby pushing the inner circumferential wall portion 262 forward.

[0061] As the inner circumferential wall portion 262 is displaced forward relative to the fixed outer circumferential wall portion 261, the end plate portion 263 elastically deforms, with the portion near the center corresponding to the inner circumferential wall portion protruding forward.

[0062] The chuck jaws 270 are arranged in a plurality on the forward-facing surface (front surface) of the end plate portion 263 of the diaphragm 260, distributed on a circle of a certain radius centered on the central axis C. As shown in Figure 3B, when the inner circumferential wall portion 262 is pushed forward and the end plate portion 263 is elastically deformed into a forward convex shape, the plurality of chuck jaws 270 open outward from the central axis C. On the other hand, as shown in Figure 2B, when the elastic deformation of the end plate portion 263 is restored, the plurality of chuck jaws 270 return to their original position and close.

[0063] <Operation> In the state where the diaphragm-type chuck device 200 is attached to the spindle 10, as shown in Figures 2A and 2B, when one end 23a of the chuck operating jaw 23 is not riding on the inner circumferential ring 21b of the bobbin 21 of the toggle mechanism 20, the intermediate sleeve 25 is positioned rearward as shown in the figure, receiving a biasing force from the push rod 210.

[0064] At this time, the front end surface 210c of the push rod 210 is separated from the rear end surface 262b of the inner circumferential wall portion 262. In other words, a gap of dimension L1 is formed between the front end surface 210c of the push rod 210 and the rear end surface 262b of the inner circumferential wall portion 262, as shown in Figure 2B.

[0065] Therefore, in this state, the diaphragm 260 is not subjected to load from the push rod 210, and the chuck jaws 270 remain closed.

[0066] As shown in Figures 3A and 3B, when the toggle mechanism 20 of the workpiece fixing device 400 is operated, one end 23a of the chuck operating jaw 23 rides onto the outer surface of the inner circumferential ring 21b of the bobbin 21, causing the intermediate sleeve 25 to move forward. When the intermediate sleeve 25 moves forward, the push rod 210, which is in contact with the front end 25a of the intermediate sleeve 25, is displaced forward against the elastic force of the compression coil spring 240, and the front end surface 210c of the push rod 210 comes into contact with the rear end surface 262b of the inner circumferential wall portion 262 of the diaphragm 260, pushing the inner circumferential wall portion 262 forward.

[0067] Since the outer peripheral wall portion 261 is fixed to the flange 250, it does not displace forward. However, as the inner peripheral wall portion 262 is pushed forward by the push rod 210, the end plate portion 263 of the diaphragm 260 elastically deforms into a convex shape, with the central portion, which is the peripheral part of the central axis C, protruding forward more than the outer peripheral portion connected to the outer peripheral wall portion 261.

[0068] As the end plate portion 263 elastically deforms into a convex shape, each chuck jaw 270 is displaced so as to move outward from the central axis C, as shown by the solid arrows in Figure 3B. As a result, the chuck jaws 270 are in an open state, where the distance between multiple chuck jaws 270 is larger than when the end plate portion 263 is not elastically deformed. With the chuck jaws 270 in the open state, the workpiece is inserted into the area enclosed by the multiple chuck jaws 270.

[0069] After the workpiece is inserted inside the chuck jaws 270, the intermediate sleeve 25 moves backward when the toggle mechanism 20 is operated, as shown in Figures 2A and 2B. As a result, the push rod 210 is displaced backward following the backward movement of the intermediate sleeve 25 due to the elastic force of the compression coil spring 240 and the end plate portion 263. When the push rod 210 is displaced backward, it separates from the diaphragm 260, and the end plate portion 263 returns to its state before elastic deformation.

[0070] When the end plate portion 263 returns to its original position, each chuck jaw 270 is displaced to move closer to the central axis C, as shown by the dashed arrows in Figure 2B. As a result, the chuck jaws 270 are in a closed state, where the distance between multiple chuck jaws 270 is smaller than when the end plate portion 263 is elastically deformed. With the chuck jaws 270 in the closed state, a workpiece inserted inside the area surrounded by multiple chuck jaws 270 when in the open state is gripped and fixed by the multiple chuck jaws 270.

[0071] In this way, the diaphragm-type chuck device 200 grips and fixes the workpiece by opening and closing the chuck jaws 270.

[0072] Furthermore, by moving the chuck force adjustment nut 24 forward relative to the spindle 10, the entire toggle mechanism 20 is moved forward relative to the spindle 10, causing the push rod 210 to move forward relative to the inner circumferential wall portion 262 of the diaphragm 260, thereby increasing the opening amount of the chuck jaws 270 when open.

[0073] On the other hand, when the chuck force adjustment nut 24 is moved backward relative to the spindle 10, the entire toggle mechanism 20 is moved backward relative to the spindle 10, causing the push rod 210 to move backward relative to the inner circumferential wall portion 262 of the diaphragm 260, thereby reducing the opening amount of the chuck jaws 270 when open.

[0074] In this way, the toggle mechanism 20 allows the opening amount of the chuck jaws 270 to be adjusted by the chuck force adjustment nut 24.

[0075] As described in detail above, the diaphragm-type chuck device 200 of this embodiment can be easily attached to and detached from the spindle 10, which is equipped with a toggle mechanism 20. Therefore, in a workpiece fixing device 300 equipped with a toggle mechanism 20, a spindle 10, and a collet chuck device 100, the diaphragm-type chuck device 200 can be attached to the spindle 10 by replacing the collet chuck device 100, thereby constituting a workpiece fixing device 400 equipped with a diaphragm-type chuck device 200.

[0076] Furthermore, the workpiece fixing device 400 can open and close the diaphragm-type chuck device 200 using the toggle mechanism 20 without using a fluid supply device. In other words, the workpiece fixing device 400 can use the same spindle 10 and toggle mechanism 20 as the workpiece fixing device 300 equipped with a collet chuck device 100.

[0077] Therefore, the diaphragm-type chuck device 200, as a workpiece fixing device 400 attached to the spindle 10 equipped with a toggle mechanism 20, reduces costs and installation space compared to a workpiece fixing device 300 equipped with a collet chuck device 100 on the spindle 10 equipped with a toggle mechanism 20.

[0078] (Desirable additional structure to prevent damage to the diaphragm 260) The amount of deformation in which the end plate portion 263 of the diaphragm 260 elastically deforms corresponds to the amount of displacement in which the push rod 210 moves forward, after the front end surface 210c comes into contact with the rear end surface 262b of the inner circumferential wall portion 262 of the diaphragm 260, and then the push rod 210 moves further forward. The amount of forward displacement of the push rod 210 corresponds to the amount of forward displacement of the intermediate sleeve 25 of the toggle mechanism 20.

[0079] Since the toggle mechanism 20 is used in common with the workpiece fixing device 300 which is equipped with a collet chuck device 100, the amount of forward displacement of the intermediate sleeve 25 is set so that the chuck sleeve 110 moves forward and generates sufficient chucking force for the collet 120 to grip the workpiece.

[0080] On the other hand, in a workpiece fixing device 400 equipped with a diaphragm-type chuck device 200, if the intermediate sleeve 25 is displaced by the same amount as the amount that displaces the chuck sleeve 110 forward, the amount of displacement of the push rod 210 corresponding to the displacement of the intermediate sleeve 25 may exceed the elastic range (the amount of deformation that can be elastically deformed) of the end face plate portion 263 of the diaphragm 260, potentially causing deformation of the end face plate portion 263. In this case, the end face plate portion 263 may undergo plastic deformation or break, resulting in a decrease in the function of the diaphragm-type chuck device 200.

[0081] Therefore, in the diaphragm-type chuck device 200 of this embodiment, the forward movement of the push rod 210 is restricted to within the range of elastic deformation (elastic range) of the end plate portion 263. Specifically, as shown in Figure 2B, it is preferable that the dimension L2 of the gap 201 between the front end surface 210d of the stepped portion formed on the rear end portion 210b of the push rod 210 and the rear end surface 220b of the adapter 220 when the toggle mechanism 20 is in the closed position of the chuck jaws 270 is set to a value within a predetermined range.

[0082] The dimension L2 of the gap 201 is set to a range (L1 < L2 < L1 + L3) from the dimension L1, which is the amount by which the push rod 210 is displaced forward until the front end surface 210c of the push rod 210 contacts the rear end surface 262b of the inner circumferential wall portion 262 of the diaphragm 260, to the sum of dimension L1 and dimension L3 (not shown), which is the amount by which the push rod 210 is displaced forward within the range of deformation of the elastic region of the end plate portion 263 after the front end surface 210c contacts the rear end surface 262b.

[0083] As a result, when the workpiece fixing device 400 moves the push rod 210 forward to open the chuck jaws 270 by the toggle mechanism 20, the front end surface 210c of the push rod 210 abuts against the rear end surface 220b of the adapter 220 before the end face plate portion 263 deforms beyond its elastic range. Therefore, the push rod 210 is prevented from moving further forward, and the end face plate portion 263 is prevented from deforming beyond its elastic range.

[0084] In the workpiece fixing device 400, a diaphragm-type chuck device 200 is attached to a spindle 10 equipped with a toggle mechanism 20, the chuck jaws 270 open when the intermediate sleeve 25 is moved forward by the toggle mechanism 20 and close when the intermediate sleeve 25 is moved backward. In contrast, in the workpiece fixing device 300, a collet chuck device 100 is attached to a spindle 10 equipped with a toggle mechanism 20, the collet 120 closes when the intermediate sleeve 25 is moved forward by the toggle mechanism 20 and opens when the intermediate sleeve 25 is moved backward.

[0085] Thus, in the case of a workpiece fixing device 400 and a collet chuck device 100, both equipped with the same toggle mechanism 20, the opening and closing operation of the chuck mechanism (chuck jaws 270, collet 120) is opposite to the operating direction of the toggle mechanism 20.

[0086] [Embodiment 2] Figure 4 is an enlarged view corresponding to Figure 2B, showing a cross-section of a workpiece fixing device 600 equipped with a diaphragm-type chuck device 500, along a plane including the central axis C of the spindle 10, and showing the chuck jaws 270 in a closed state. Figure 5 is an enlarged view corresponding to Figure 3B, showing a cross-section of the diaphragm-type chuck device 500, along a plane including the central axis C of the spindle 10, and showing the chuck jaws 270 in an open state. The diaphragm-type chuck device 500 is another embodiment (Embodiment 2) of the diaphragm-type chuck device according to the present invention.

[0087] The diaphragm-type chuck device 500, like the diaphragm-type chuck device 200 of Embodiment 1, is detachably attached to the spindle 10 equipped with the toggle mechanism 20. Therefore, the spindle 10 equipped with the toggle mechanism 20 can be selectively equipped with the collet chuck device 100, the diaphragm-type chuck device 200, or the diaphragm-type chuck device 500.

[0088] The spindle 10 and toggle mechanism 20 to which the diaphragm-type chuck device 500 is attached are the same as the spindle 10 and toggle mechanism 20 in the workpiece fixing devices 300 and 400 in the previously described embodiment 1, so their description will be omitted.

[0089] (Diaphragm-type chuck device 500) As shown in Figures 4 and 5, the diaphragm-type chuck device 500 is configured such that the push rod 210 in the diaphragm-type chuck device 200 of Embodiment 1 is divided into two members (collar portion 212 and rod portion 213) along the direction of the central axis C, and one of the resulting rod portions 213 is connected to the inner circumferential wall portion 262 of the diaphragm 260 by a joint 280. In addition, the diaphragm-type chuck device 500 is equipped with a first compression coil spring 241 and a second compression coil spring 242 (elastic member) instead of the compression coil spring 240.

[0090] The diaphragm-type chuck device 500 is equipped with an adapter 221 in place of the adapter 220 in the diaphragm-type chuck device 200. The adapter 221 has a keyway 221c formed on a part of its outer surface in the circumferential direction, extending parallel to the central axis C. A key pin 26, provided on a specific part of the spindle 10 in the circumferential direction, is inserted into the keyway 221c. With the key pin 26 inserted into the keyway 221c, the spindle 10 and the adapter 221 become one unit in the circumferential direction around the central axis C. The adapter 221 can also be removed from the spindle 10 by moving it forward along the central axis C.

[0091] The adapter 221 includes a key pin 219 that is inserted into a keyway 214c formed on the outer circumferential surface of the rod 214, and also has a stopper surface 221d against which the stopper 218 abuts.

[0092] The diaphragm-type chuck device 500, with the configuration described above, increases the gripping force of the chuck jaws 270 in gripping the workpiece compared to the diaphragm-type chuck device 200 in Embodiment 1.

[0093] More specifically, the push rod 210 in the diaphragm-type chuck device 200 is divided into two parts: a collar portion 212 positioned rearward along the central axis C, and a rod portion 213 positioned forward of the collar portion 212.

[0094] The collar portion 212 is movable in the front-to-back direction in accordance with the front-to-back movement of the intermediate sleeve 25. The rod portion 213 is positioned forward and separated from the collar portion 212. When the collar portion 212 and the rod portion 213 are separated, they can move independently of each other in the direction of the central axis C. On the other hand, after the collar portion 212 moves forward and comes into contact with the rod portion 213, the collar portion 212 and the rod portion 213 move forward together as a single unit.

[0095] When one end 23a of the chuck jaw 23 is not riding on the inner circumferential ring 21b of the bobbin 21 of the toggle mechanism 20, the collar portion 212 moves rearward from the rod portion 213, and a gap of dimension L4 is formed between the front end of the collar portion 212 and the rear end of the rod portion 213. This state is the closed state of the chuck jaw 270 (Figure 4).

[0096] When one end 23a of the chuck jaw 23 is resting on the inner circumferential ring 21b of the bobbin 21 of the toggle mechanism 20, the collar portion 212 and the rod portion 213 are in contact, and the collar portion 212 pushes the rod portion 213 forward, causing the chuck jaw 270 to open (Figure 5).

[0097] The collar portion 212 is constantly pressed rearward by a first compression coil spring 241, which is positioned between it and the adapter 221 in a state shortened from its natural length. As a result, the rear end portion 212b of the collar portion 212 is always in contact with the front end portion 25a of the intermediate sleeve 25. Therefore, when the intermediate sleeve 25 moves forward, the collar portion 212 is pushed forward by the intermediate sleeve 25 and moves forward, while when the intermediate sleeve 25 does not move forward, the intermediate sleeve 25 is pushed rearward by the collar portion 212.

[0098] In addition, when the chuck jaws 270 are closed (Figure 4) and open (Figure 5), a gap 202 is formed between the collar portion 212 and the adapter 221 along the axial direction of the central axis C.

[0099] The rod portion 213 comprises a rod 214, a cover portion 215, a bolt 216, a spacer 217, and a stopper 218. The rod 214 is formed in a cylindrical shape along the central axis C. A keyway 214c extending parallel to the central axis C is formed on the outer circumferential surface of the rod 214 at a specific angular position about the central axis C. A key pin 219 fixed to the adapter 221 is inserted into the keyway 214c. As a result, the rod 214 is restricted from rotating about the central axis C relative to the adapter 221, while movement along the direction of the central axis C is permitted.

[0100] The cover portion 215 is positioned in contact with the rear end of the rod 214. The cover portion 215 has a through hole formed in its center and covers at least a portion of the rear end face of the spacer 217. The outer diameter of the cover portion 215 is larger than the outer diameter of the rear end of the rod 214.

[0101] The bolt 216 is fastened to the rear end of the rod 214 via the cover portion 215, fixing the cover portion 215 to the rod 214. When the fastening of the bolt 216 is loosened and removed from the rod 214, the cover portion 215 is removed from the rod 214.

[0102] Furthermore, in the case where the lid portion 215 is fixed to the rod 214, the rod portion 213 does not need to have a bolt 216. For example, the lid portion 215 can be provided with a female thread and the rod 214 with a male thread, and the lid portion 215 can be fixed to the rod 214 by screwing the male and female threads together.

[0103] The spacer 217 is positioned on the outer side of the outer circumferential surface of the rod 214. The spacer 217 is constantly pressed backward by a second compression coil spring 242, which is positioned between the spacer 217 and the adapter 221 in a state shortened from its natural length. As the spacer 217 is pressed backward, its rear end abuts against the cover portion 215, so that the entire rod portion 213 is constantly pressed backward.

[0104] Furthermore, multiple spacers 217 with different lengths along the central axis C may be provided. In this case, the rod portion 213 can replace the spacer 217 positioned outside the outer circumferential surface of the rod 214 with another spacer 217 of a different length. By replacing the spacer 217, the diaphragm-type chuck device 500 can change the compressed length from the natural length of the second compression coil spring 242, thereby adjusting the strength of the rearward pressing force (biasing force) that constantly acts on the rod portion 213.

[0105] Furthermore, the spacer 217 may have a screw groove formed on its inner circumferential surface. The screw groove formed on the outer circumferential surface of the rod 214 and the screw groove of the spacer 217 may be screwed together, allowing the position of the spacer 217 relative to the rod 214 in the direction of the central axis C to be movable. The rod portion 213 configured in this way can have its position in the direction of the central axis C adjusted by rotating the spacer 217 around the central axis C. By moving the position of the spacer 217, the compressed length from the natural length of the second compression coil spring 242 can be changed, thereby adjusting the strength of the rearward pressing force (biasing force) that constantly acts on the rod portion 213.

[0106] The stopper 218 is positioned on the outside of the outer surface of the front of the rod 214, where the diameter is narrowed, and is pressed against the stepped end face, where the diameter is narrowed, from the tip side, and is fixed to the front end 214a of the rod 214a by screwing in the joint 280. The rod portion 213 is constantly pressed backward by the elastic force of the second compression coil spring 242 and tries to move backward, but stops when the rear end of the stopper 218 abuts against the abutment surface 221d of the adapter 221. In other words, the amount of backward movement of the rod portion 213 is defined by the stopper 218.

[0107] As a result, when the chuck jaws 270 are closed (Figure 4), a gap of dimension L4 is formed between the rear end of the rod portion 213 and the front end of the collar portion 212, and the rod portion 213 and the collar portion 212 are held apart.

[0108] The dimension L4 between the rod portion 213 and the collar portion 212 is smaller than the gap between the collar portion 212 and the adapter 221. Furthermore, the dimension L4 between the rod portion 213 and the collar portion 212 should be approximately the same as the dimension L1 of the gap between the push rod 210 and the inner circumferential wall portion 262 in the diaphragm-type chuck device 200 of Embodiment 1 (L4 ≈ L1).

[0109] A screw groove is formed on the outer circumferential surface of the front end 214a of the rod 214. This screw groove engages with a screw groove formed on the inner circumferential surface of the joint 280, thereby connecting the rear of the joint 280 to the front end 214a of the rod 214.

[0110] The outer surface of the inner circumferential wall portion 262 of the diaphragm 260 has screw grooves similar to those on the outer surface of the front end portion 214a of the rod 214. These screw grooves engage with the screw grooves formed on the inner circumferential surface of the joint 280, thereby connecting the front portion of the joint 280 to the inner circumferential wall portion 262 of the diaphragm 260. Therefore, the joint 280 integrally connects the rod portion 213 to the inner circumferential wall portion 262 of the diaphragm 260.

[0111] The inner circumferential wall portion 262 of the diaphragm 260 is connected to the rod portion 213 and is therefore subjected to the biasing force of the second compression coil spring 242. However, with the end face plate portion 263 not elastically deformed and the chuck jaws 270 closed, the rear end of the stopper 218 is set to abut against the abutment surface 221d of the adapter 221. With the rear end of the stopper 218 abutting against the abutment surface 221d of the adapter 221, a gap of dimension L5 is formed between the front end of the stopper 218 and the rear end of the flange 250 (Figure 4).

[0112] Dimension L5 is set to a value that displaces the rod portion 213 forward within the range of deformation of the end plate portion 263's elastic range, and is smaller than the dimension L4 of the gap between the rear end of the rod portion 213 and the front end of the collar portion 212 (L5 < L4).

[0113] As the rod portion 213 is displaced forward, the end plate portion 263 elastically deforms and the chuck jaws 270 open. However, before the end plate portion 263 deforms beyond its elastic range, the front end of the stopper 218 abuts against the rear end of the flange 250, preventing the rod portion 213 from being displaced further forward. At this time, a gap of dimension L5 is formed between the rear end of the stopper 218 and the abutting surface 221d of the adapter 221 (Figure 5).

[0114] <Operation> In the state where the diaphragm-type chuck device 500 is attached to the spindle 10, the workpiece fixing device 600, similar to the workpiece fixing device 400 of Embodiment 1, is positioned rearward as shown in Figure 4 when one end 23a of the chuck operating jaw 23 is not riding on the inner circumferential ring 21b of the bobbin 21 of the toggle mechanism 20, due to a biasing force from the collar portion 212 (rearward pressing force from the first compression coil spring 241).

[0115] At this time, the collar portion 212 is separated from the rod portion 213, the intermediate sleeve 25 does not elastically deform the end plate portion 263 of the diaphragm 260, and the chuck jaws 270 are in a closed state.

[0116] On the other hand, the rod portion 213 is constantly subjected to a rearward pressing force by the second compression coil spring 242, and the inner circumferential wall portion 262 of the diaphragm 260 is constantly subjected to a rearward biasing force (rearward pressing force by the second compression coil spring 242) via the joint 280. As a result, the end plate portion 263 can be elastically deformed so that the portion around the central axis C is recessed rearward.

[0117] However, with the chuck jaws 270 closed as shown in Figure 4, and the end plate portion 263 not elastically deformed, the rear end of the stopper 218 abuts against the abutment surface 221d of the adapter 221. As a result, the rod portion 213 does not move further back than the position where the stopper 218 abuts against the abutment surface 221d of the adapter 221, and the end plate portion 263 does not elastically deform to the point of being recessed backward.

[0118] In this way, the diaphragm-type chuck device 500, when the chuck jaws 270 are closed, has the adapter 221 receive the rearward biasing force acting on the end plate portion 263, thereby reducing the load acting on the end plate portion 263, increasing the durability of the diaphragm 260 and extending its lifespan.

[0119] In the workpiece fixing device 600, when one end 23a of the chuck operating jaw 23 is resting on the inner circumferential ring 21b of the bobbin 21 of the toggle mechanism 20, the intermediate sleeve 25 moves forward. When the intermediate sleeve 25 is displaced forward against the biasing force it receives from the collar portion 212, as shown in Figure 5, the intermediate sleeve 25 displaces the collar portion 212 forward.

[0120] When the collar portion 212 is displaced forward by more than the dimension L4, the front end of the collar portion 212 comes into contact with the rear end of the rod portion 213, and the collar portion 212 pushes the rod portion 213 forward against the biasing force of the second compression coil spring 242.

[0121] The rod portion 213 moves forward as it is pushed by the collar portion 212. At this time, the rear end of the stopper 218 separates from the abutment surface 221d of the adapter 221. As the rod portion 213 moves forward, the inner circumferential wall portion 262 of the diaphragm 260, which is connected to the rod portion 213 via the joint 280, is pushed forward.

[0122] The outer peripheral wall portion 261 is fixed to the flange 250 and therefore does not displace forward, but the inner peripheral wall portion 262 displaces forward together with the joint 280. As a result, the end plate portion 263 of the diaphragm 260 elastically deforms into a convex shape, with the central portion, which is the peripheral part of the central axis C, protruding forward more than the outer peripheral portion connected to the outer peripheral wall portion 261.

[0123] In this state, the front end of the stopper 218 abuts against the rear end of the flange 250. As a result, the rod portion 213 does not move forward beyond the position where the stopper 218 abuts against the flange 250, and the end plate portion 263 does not deform forward beyond its convex elastic deformation.

[0124] As the end plate portion 263 elastically deforms into a convex shape, each chuck jaw 270 is displaced so as to move outward from the central axis C, as shown by the solid arrows in Figure 5. As a result, the chuck jaws 270 are in an open state, where the distance between multiple chuck jaws 270 is larger than when the end plate portion 263 is not elastically deformed. With the chuck jaws 270 in the open state, the workpiece is inserted into the area enclosed by the multiple chuck jaws 270.

[0125] Thus, in the diaphragm-type chuck device 500, when the chuck jaws 270 are open, the stopper 218 abuts against the flange 250 before the end plate portion 263 deforms beyond its elastic range, preventing the rod portion 213 from being displaced further forward and thus preventing deformation beyond the elastic range of the end plate portion 263.

[0126] In the workpiece fixing device 600 equipped with a diaphragm-type chuck device 500, after the workpiece is inserted inside the chuck jaws 270, the intermediate sleeve 25 moves backward by operating the toggle mechanism 20, as shown in Figure 4. As a result, the collar portion 212 is displaced backward together with the rod portion 213, following the backward movement of the intermediate sleeve 25, due to the elastic force of the first compression coil spring 241, the elastic force of the second compression coil spring 242 acting on the rod portion 213, and the elastic force of the end face plate portion 263.

[0127] The rod portion 213 stops when it is displaced rearward by a dimension L5, as the stopper 218 abuts against the abutment surface 221d of the adapter 221. At the position where the rod portion 213 stops, the elastic deformation of the end plate portion 263 has returned to its original state. When the end plate portion 263 returns to its original state, each chuck jaw 270 is displaced to move closer to the central axis C, as shown by the dashed arrows in Figure 4.

[0128] As a result, the chuck jaws 270 are in a closed state, where the distance between the multiple chuck jaws 270 is smaller than the distance when the end plate portion 263 is elastically deformed. With the chuck jaws 270 in the closed state, the workpiece inserted inside the area surrounded by the multiple chuck jaws 270 when in the open state is gripped and fixed by the multiple chuck jaws 270.

[0129] In the range between the state in which the end plate portion 263 is elastically deformed and the state just before it fully returns to its original state before elastic deformation (the state just before the stopper 218 abuts against the abutment surface 221d of the adapter 221), a load corresponding to the elastic force of the second compression coil spring 242 acts on the end plate portion 263 of the diaphragm 260, in addition to the elastic force of the end plate portion 263.

[0130] Thus, the diaphragm-type chuck device 500 of Embodiment 2 can grip and fix a workpiece by opening and closing the chuck jaws 270, and can also increase the gripping force (chuck force) for gripping the workpiece compared to the diaphragm-type chuck device 200 of Embodiment 1.

[0131] The collar portion 212 is displaced further rearward by the elastic force of the first compression coil spring 241, exceeding the dimension L5, and the collar portion 212 separates from the rod portion 213 and stops at a position where the rearward displacement of the intermediate sleeve 25 has stopped, and is located a distance L4 rearward from the rod portion 213.

[0132] As described in detail above, the diaphragm-type chuck device 500 of this embodiment can be easily attached to and detached from the spindle 10, which is equipped with a toggle mechanism 20. Therefore, in a workpiece fixing device 300 equipped with a toggle mechanism 20, a spindle 10, and a collet chuck device 100, the diaphragm-type chuck device 500 can be attached to the spindle 10 by replacing the collet chuck device 100, thereby constituting a workpiece fixing device 600 equipped with a diaphragm-type chuck device 500.

[0133] Furthermore, the workpiece fixing device 600 can open and close the diaphragm-type chuck device 500 using the toggle mechanism 20 without using a fluid supply device. In other words, the workpiece fixing device 600 can use the same spindle 10 and toggle mechanism 20 as the workpiece fixing device 300 equipped with a collet chuck device 100.

[0134] Therefore, the diaphragm-type chuck device 500, as a workpiece fixing device 600 attached to the spindle 10 equipped with a toggle mechanism 20, reduces costs and installation space compared to a workpiece fixing device 300 equipped with a collet chuck device 100 on the spindle 10 equipped with a toggle mechanism 20.

[0135] Furthermore, in the diaphragm-type chuck device 500, the dimensions L5 of the gap between the stopper 218 and the abutment surface 221d of the adapter 221, and the gap between the stopper 218 and the flange 250, are set within the elastic range of the end plate portion 263, thus preventing the end plate portion 263 from plastically deforming or breaking.

[0136] Furthermore, the diaphragm-type chuck device 500 can adjust the opening amount of the chuck jaws 270 when open by adjusting the dimension L5 of the gap between the stopper 218 and the abutment surface 221d of the adapter 221.

[0137] Furthermore, in the diaphragm-type chuck device 500, the key pin 26 of the spindle 10 is inserted into the key groove 221c of the adapter 221, and the key pin 219 of the adapter 221 is inserted into the key groove 214c of the rod 214. This allows the chuck jaws 270 to be fixed in a predetermined phase relative to the spindle 10 on a circumference of a circle with a certain radius centered on the central axis C. Therefore, the diaphragm-type chuck device 500, with its chuck jaws 270 positioned in a predetermined phase relationship with the spindle 10, can machine workpieces with polygonal or irregularly shaped cross-sections while following the phase of the workpiece around the central axis C, thereby achieving highly accurate machining.

[0138] The toggle mechanism to be combined with the diaphragm-type chuck device according to the present invention is not limited to the configuration of the toggle mechanism 20 in the embodiments 1 and 2 described above. The toggle mechanism to be combined with the diaphragm-type chuck device according to the present invention is any mechanism that opens and closes the diaphragm-type chuck devices 200 and 500 by being displaced back and forth along the central axis C of the main spindle 10.

[0139] [Embodiment 3] Figures 6A, 6B, and 6C are enlarged views of the main parts of a cross-section of a workpiece fixing device 910 equipped with a diaphragm-type chuck device 700, with the cross-section including the central axis C of the spindle 10. Figure 6A shows the chuck jaws 770 in the open state, Figure 6B shows the chuck jaws 770 in the closed state gripping the workpiece, and Figure 6C shows the chuck jaws 770 in the open state discharging the workpiece W. The diaphragm-type chuck device 700 is another embodiment (Embodiment 3) of the diaphragm-type chuck device according to the present invention.

[0140] <Configuration of Workpiece Fixing Device 910> The spindle 10 and toggle mechanism 20 to which the diaphragm-type chuck device 700 is attached in the workpiece fixing device 910 are the same as the spindle 10 and toggle mechanism 20 in the workpiece fixing devices 300, 400, and 600 in Embodiment 1 described above, so their explanation is omitted. Figures 6A to 6C also show the headstock 11 that rotatably supports the spindle 10. The headstock 11 does not rotate.

[0141] (Diaphragm-type chuck device 700) As shown in Figure 6A, the diaphragm-type chuck device 700 of Embodiment 3 includes a collar portion 712 and a rod portion 713 corresponding to a push rod, an adapter 721, a cap nut 730, a first compression coil spring 741 and a second compression coil spring 742, a flange 750, a diaphragm 760, a chuck jaw 770, a workpiece receiving member 790, and a cover member 780.

[0142] The collar portion 712 has the same configuration as the collar portion 212 in the diaphragm-type chuck device 500 of Embodiment 2. Also, the rod portion 713 is the same as the rod portion 213 in the diaphragm-type chuck device 500, the adapter 721 is the same as the adapter 221, the cap nut 730 is the same as the cap nut 230, the first compression coil spring 741 is the same as the first compression coil spring 241, the second compression coil spring 742 is the same as the second compression coil spring 242, the diaphragm 760 is the same as the diaphragm 260, and the chuck jaw 770 is the same as the chuck jaw 270. Since these components have the same configuration and perform the same functions, their descriptions are omitted.

[0143] The rod section 713 comprises a rod 714, a cover section 715, and a spacer 717. The rod 714 has the same configuration as the rod 214, the cover section 715 as the cover section 215, and the spacer 717 as the spacer 217, and each performs the same function.

[0144] The flange 750 is fixed to the main shaft 10 and rotates integrally with the main shaft 10 around axis C. The flange 750 is formed in a disc shape with a through hole 752 in the center that penetrates in the direction of axis C and has a female thread formed therein. The flange 750 has the same configuration as the flange 250 and performs the same function as the flange 250. In addition to the same configuration as the flange 250, the flange 750 has an outer peripheral groove 753 that extends in the circumferential direction of the disc formed on the outer peripheral surface 751 of the disc, and a radial hole 754 that extends radially from a part of the outer peripheral groove 753 to the through hole 752. The radial hole 754 faces the through hole 752.

[0145] The workpiece receiving member 790 is formed in a cylindrical shape. The workpiece receiving member 790 is assembled by screwing male threads formed on the outer circumference of the cylinder into female threads in the through holes 752 of the flange 750, and is positioned to penetrate in the direction of axis C. The workpiece receiving member 790 rotates integrally with the flange 750 around axis C. The tip surface 792 of the cylinder of the workpiece receiving member 790, on the side closer to the diaphragm 760, abuts against the end face of the workpiece W that is chucked by the chuck jaws 770, thereby performing the function of positioning the workpiece W. Inside the cylinder of the workpiece receiving member 790, a workpiece ejection rod 50, which will be described later, is passed in the direction of axis C.

[0146] The workpiece receiving member 790 has an outer circumferential groove 793 formed on its outer circumferential surface. The workpiece receiving member 790 has an axial hole 794 formed on its circumferential wall, extending in the axial C direction from a part of the outer circumferential groove 793 to the tip surface 792 of the cylinder. The axial hole 794 faces the tip surface 792. The radial hole 754 of the flange 750 communicates with the outer circumferential groove 793 of the workpiece receiving member 790, thereby creating communication between the outer circumferential groove 753 of the flange 750, the radial hole 754, the outer circumferential groove 793 of the workpiece receiving member 790, and the axial hole 794.

[0147] The cover member 780 is formed in a cylindrical shape extending in the direction of axis C. The rear end portion of the cover member 780 in the direction of axis C is fixed to a flange component 11a provided on the non-rotating headstock 11, and the front end portion is positioned to cover the outer circumferential surface 751 of the flange 750 and the outer circumferential surface of the diaphragm 760 from the radially outside. The front end in the direction of axis C is the side closer to the diaphragm 760, and the rear end is the side further away from the diaphragm 760. By covering the front end of the spindle 10, the flange 750 and the diaphragm 760, the cover member 780 prevents or suppresses the adhesion of scattered coolant and chips to these parts of the spindle 10.

[0148] The inner circumferential surface of the cylindrical cover member 780 faces the outer circumferential surface 751 of the flange 750 with a small gap in between. The inner circumferential surface of the cylindrical cover member 780 and the outer circumferential surface of the diaphragm 760 are separated.

[0149] The cover member 780 has an axial hole 731 formed in the circumferential wall of the cylinder, extending in the direction of axis C. The axial hole 731 is connected to a connecting hole 732 formed through to the inside of the cylinder at the tip of the circumferential wall. The connecting hole 732 faces an outer circumferential groove 753 formed on the outer circumferential surface of the flange 750, which is opposite the inner circumferential surface of the cover member 780. The connection between the connecting hole 732 of the cover member 780 and the outer circumferential groove 753 of the flange 750 allows the axial hole 731 of the cover member 780, the connecting hole 732, the outer circumferential groove 753 of the flange 750, the radial hole 754, the outer circumferential groove 793 and the axial hole 794 of the workpiece receiving member 790 to communicate, forming a passage for the flow of fluid such as compressed air A.

[0150] <Operation> The diaphragm-type chuck device 700 configured as described above is detachably attached to the spindle 10 equipped with the toggle mechanism 20, similar to the diaphragm-type chuck device 200. Therefore, the spindle 10 equipped with the toggle mechanism 20 can be selectively equipped with either the collet chuck device 100 or the diaphragm-type chuck device 700.

[0151] Furthermore, as shown in Figure 6B, the diaphragm-type chuck device 700 can position the workpiece W in the axial direction C by gripping the workpiece W with the chuck jaws 770 while the end face of the workpiece W is abutting against the tip surface 792 of the workpiece receiving member 790.

[0152] Furthermore, the diaphragm-type chuck device 700 can detect whether the end face of the workpiece W is abutting against the tip surface 792 of the workpiece receiving member 790 (workpiece W seating detection) by supplying a fluid, such as compressed air A, to a connector 12 that communicates with an axial hole 731 provided on the flange part 11a of the headstock 11 to which the cover member 780 is attached, while detecting the pressure.

[0153] In other words, when compressed air A is supplied to the connector 12, the compressed air A flows from the connector 12 through the axial hole 731 and connection hole 732 of the cover member 780, the outer circumferential groove 753 and radial hole 754 of the flange 750, and the outer circumferential groove 793 and axial hole 794 of the workpiece receiving member 790 to the tip surface 792 of the workpiece receiving member 790.

[0154] Here, if the end face of the workpiece W is seated against the front end surface 792 of the workpiece receiving member 790 and gripped by the chuck jaws 770, then the end face of the workpiece W is seated against the front end surface 792. Therefore, since the end face of the workpiece W closes the opening on the front end surface 792 side of the axial hole 794, the compressed air A is trapped inside the axial hole 731, the connecting hole 732, the outer peripheral groove 753, the radial hole 754, the outer peripheral groove 793, and the axial hole 794, and the pressure detected on the connector 12 side increases.

[0155] On the other hand, if the end face of the workpiece W is gripped by the chuck jaws 770 without abutting against the tip surface 792 of the workpiece receiving member 790, the end face of the workpiece W is not seated on the tip surface 792. Therefore, since the end face of the workpiece W does not block the opening on the tip surface 792 side of the axial hole 794, the compressed air A is exhausted to the outside through the opening on the tip surface 792 side of the axial hole 794, and the supply pressure detected on the connector 12 side does not increase.

[0156] Therefore, by detecting the pressure of the compressed air A supplied from the connector 12 using a detection means such as a pressure sensor provided on the connector 12 side, it is possible to detect whether the end face of the workpiece W is seated in a position where it abuts against the front end face 792 of the workpiece receiving member 790, and to determine whether the workpiece W is positioned in a seated state.

[0157] Furthermore, when the diaphragm-type chuck device 700 discharges the workpiece W held by the chuck jaws 770, the intermediate sleeve 25 moves the push rod 710 forward along axis C, thereby opening the chuck jaws 770 and releasing the grip on the workpiece W. At this time, due to the presence of coolant or other factors, the end face of the workpiece W may remain in close contact with the tip surface 792 of the workpiece receiving member 790, and the workpiece W may not separate from the chuck device 700.

[0158] Therefore, in order to reliably separate the workpiece W from the chuck device 700, the spindle 10 is equipped with an ejector rod 50 that physically pushes and ejects the workpiece W. The ejector rod 50 is provided inside the intermediate sleeve 25 so as to be movable in the direction of axis C. With the chuck jaws 770 open, as shown in Figure 6C, the ejector rod 50 moves forward along the direction of axis C, and the tip of the ejector rod 50 passes through the inner portion 795 of the cylindrical workpiece receiving member 790 and protrudes forward from the tip surface 792, thereby pushing the workpiece W forward and reliably separating and ejecting the workpiece W from the chuck device 700.

[0159] Thus, the diaphragm-type chuck device 700 of Embodiment 3 can have both an ejector rod 50 for discharging the workpiece W and a mechanism for supplying a fluid such as compressed air A to the seating surface (tip surface 792) of the workpiece W.

[0160] Furthermore, when the diaphragm 760 is not gripping the workpiece W, the compressed air A supplied from the connector 12 to the tip surface 792 through the axial hole 731, connection hole 732, outer groove 753, radial hole 754, outer groove 793, and axial hole 794 can be ejected from the axial hole 794, thereby blowing away any coolant or chips adhering to the area around the tip surface 792 and performing a cleaning function. In this case, the diaphragm-type chuck device 700 may be supplied with another fluid, such as liquid, from the connector 12 instead of compressed air A.

[0161] Furthermore, if the ejector rod 50 is formed hollow, by forming a hole in the peripheral wall of the tip of the ejector rod 50, the tip of the ejector rod 50 protrudes forward from the tip surface 792 of the workpiece receiving member 790. By supplying compressed air A or other fluid to the hollow portion of the ejector rod 50 from the rear in the direction of axis C, the compressed air A or other fluid is ejected from the hole in the peripheral wall of the tip of the ejector rod 50, blowing away coolant and chips adhering to the area around the tip surface 792, thereby providing a cleaning function.

[0162] [Modified Version] <Configuration of Work Fixing Device 920> Figures 7A, 7B, 7C, and 7D show a work fixing device 920 equipped with a diaphragm-type chuck device 800, which is a preferred modified version of the diaphragm-type chuck device 700 shown in Figures 6A to 6C. Figure 7A is an enlarged view of the main part corresponding to Figure 6A showing the chuck jaws 770 in the open state, Figure 7B is an enlarged view of the work receiving member 890, Figure 7C is an enlarged view of the main part corresponding to Figure 6B showing the chuck jaws 770 closed and gripping the workpiece W, and Figure 7D is an enlarged view of the main part corresponding to Figure 6C showing the chuck jaws 770 open and discharging the workpiece W.

[0163] The spindle 10 and toggle mechanism 20 to which the diaphragm-type chuck device 800 is attached in the workpiece fixing device 920 are the same as the spindle 10 and toggle mechanism 20 in the workpiece fixing devices 300 and 400 in the previously described embodiment 1, so their description is omitted.

[0164] (Diaphragm-type chuck device 800; desirable additional structure for ejecting workpiece W) The modified diaphragm-type chuck device 800 includes a collar portion 712 and a rod portion 713 corresponding to a push rod, an adapter 721, a cap nut 730, a first compression coil spring 741 and a second compression coil spring 742, a flange 750, a diaphragm 760, a chuck jaw 770, a workpiece receiving member 890, and a cover member 780.

[0165] The modified diaphragm-type chuck device 800 has the same configuration as the diaphragm-type chuck device 700 of Embodiment 3, except that it is equipped with a workpiece receiving member 890 instead of the workpiece receiving member 790 as a desirable additional structure for ejecting the workpiece W. Therefore, the description of the collar portion 712, rod portion 713, adapter 721, cap nut 730, first compression coil spring 741, second compression coil spring 742, flange 750, diaphragm 760, chuck jaws 770, and cover member 780 is omitted.

[0166] As shown in Figure 7B, the workpiece receiving member 890 comprises a cartridge 891, a workpiece receiving component 892, and a shaft 893. The cartridge 891 and the workpiece receiving component 892 are formed in a cylindrical shape as a whole, similar to the workpiece receiving member 790.

[0167] The cartridge 891, like the workpiece receiving member 790, is formed in a cylindrical shape, and is fixed to the flange 750 by screwing male threads formed on the outer circumference of the cylinder into female threads formed in the through holes of the flange 750. The cartridge 891, like the workpiece receiving member 790, has an outer circumference groove 891a that communicates with the radial hole 754 of the flange 750, and an axial hole 891b that extends in the axial direction C to the tip surface 891c of the cylinder.

[0168] The workpiece receiving component 892 comprises a disc portion 892a and a shaft portion 892b. The disc portion 892a is the part corresponding to the tip in the axial direction C of the workpiece receiving member 790, and is formed with an outer diameter similar to that of the cylinder of the cartridge 891. It is configured to be displaceable in the axial direction C between a position in close contact with the tip surface 891c of the cartridge 891 and a position away from the tip surface 891c. When the disc portion 892a is positioned in close contact with the tip surface 891c of the cartridge 891, a connecting hole 892c communicating with the axial hole 891b is formed therein. The shaft portion 892b is formed extending from the center of the disc portion 892a toward the rear in the axial direction C within the inner cavity of the cylinder of the cartridge 891.

[0169] The shaft 893 is formed extending in the axial direction C within the inner cavity of the cylinder of the cartridge 891. The front end 893a of the shaft 893 is connected to the shaft portion 892b of the workpiece receiving component 892, and the shaft 893 and the workpiece receiving component 892 are movable together along the axial direction C.

[0170] The rear end portion 893b of the shaft 893 is formed behind the rear end surface 891d of the cartridge 891 in the direction of axis C. The rear end portion 893b of the shaft 893 is the portion that the ejector rod 50, which has moved forward in the direction of axis C, abuts against and is pushed forward by the ejector rod 50. As the rear end portion 893b of the shaft 893 is pushed forward by the ejector rod 50, the shaft 893 and the workpiece receiving component 892 move forward along the direction of axis C.

[0171] In the diaphragm-type chuck device 800 configured in this way, as shown in Figure 7C, when the end face of the workpiece W is seated with abutting the front face of the workpiece receiving part 892 and the workpiece W is gripped by the chuck jaws 770, the workpiece receiving part 892 is pushed backward in the direction of axis C by the workpiece W, so that the disc portion 892a is positioned in close contact with the front face 891c of the cartridge 891. In this state, the radial hole 754 of the flange 750, the outer peripheral groove 891a of the cartridge 891, the axial hole 891b, and the connection hole 892c of the workpiece receiving part 892 are in communication.

[0172] Therefore, the axial hole 731 and connection hole 732 of the cover member 780, the outer groove 753 and radial hole 754 of the flange 750, the outer groove 891a and axial hole 891b of the cartridge 891, and the connection hole 892c of the workpiece receiving part 892 are in communication, forming a passage for the flow of fluid such as compressed air A. As a result, when compressed air A is supplied to the connector 12, the compressed air A flows from the connector 12 through the axial hole 731 and connection hole 732 of the cover member 780, the outer groove 753 and radial hole 754 of the flange 750, the outer groove 891a and axial hole 891b of the cartridge, and the connection hole 892c of the workpiece receiving part 892 to the tip surface of the workpiece receiving part 892.

[0173] Therefore, the compressed air A is trapped inside the axial hole 731, the connecting hole 732, the outer groove 753, the radial hole 754, the outer groove 891a, the axial hole 891b, and the connecting hole 892c, causing the pressure detected on the connector 12 side to increase.

[0174] On the other hand, when the workpiece W is held by the chuck jaws 770, and the end face of the workpiece W is not abutting against the front face of the workpiece support part 892, the end face of the workpiece W does not block the opening on the front face side of the connection hole 892c. Also, because the workpiece support part 892 is not pushed backward in the direction of axis C by the workpiece W, the disc portion 892a is separated from the front face 891c of the cartridge 891, and the axial hole 891b of the cartridge 891 and the connection hole 892c of the workpiece support part 892 do not communicate.

[0175] Therefore, even if compressed air A is supplied to the connector 12, the compressed air A is exhausted to the outside between the end face of the workpiece W and the connector 12, and the supply pressure detected on the connector 12 side does not increase.

[0176] Thus, the diaphragm-type chuck device 800, like the diaphragm-type chuck device 700, can detect whether the end face of the workpiece W is abutting against and seated against the tip surface of the disc portion 892a of the workpiece receiving component 892 (workpiece seating detection) by supplying a fluid, such as compressed air A, to a connector 12 that communicates with an axial hole 731 provided on the flange component 11a of the headstock 11 to which the cover member 780 is attached, while detecting the pressure.

[0177] In the diaphragm-type chuck device 700 shown in Figures 6A to 6C, if the gripped workpiece W has a hole formed at its diametrical center with an inner diameter larger than the outer diameter of the tip of the ejector rod 50, the tip of the ejector rod 50, which protrudes forward from the tip surface 792 of the workpiece receiving member 790, will be inserted into the hole formed at the center of the workpiece W, making it impossible to push the end face of the workpiece W forward. Therefore, there is a possibility that the workpiece W cannot be reliably released from the chuck device 700.

[0178] In contrast, in the modified diaphragm-type chuck device 800, with the diaphragm 760 open, as shown in Figure 7D, the ejector rod 50 moves forward along the axis C, and the tip of the ejector rod 50 abuts against the rear end 893b of the shaft 893, pushing the shaft 893 forward. Then, the workpiece receiving component 892, which is coupled to the front end 893a of the shaft 893, moves forward away from the tip surface 891c of the cartridge 891, causing the tip surface of the workpiece receiving component 892 to push the workpiece W forward, separating the workpiece W from the chuck device 800 and discharging it.

[0179] Thus, in the modified diaphragm-type chuck device 800, even if the gripped workpiece W has a hole formed in its diametrical center that is larger than the outer diameter of the tip of the ejector rod 50, the workpiece receiving component 892 that contacts the end face of the workpiece W moves forward, pushing the workpiece W forward with the entire surface of the tip of the workpiece receiving component 892. Therefore, even if a hole with an inner diameter larger than the outer diameter of the tip of the ejector rod 50 is formed in the center of the workpiece W, the ejector rod 50 and the workpiece receiving component 892 can reliably separate the workpiece W from the chuck device 800 and discharge it. Cross-reference of related applications

[0180] This application claims priority based on Japanese Patent Application No. 2024-170230, filed with the Japan Patent Office on 30 September 2024, all of which disclosures are incorporated herein by reference in their entirety.

Claims

1. A diaphragm-type chuck device having a toggle mechanism that moves an intermediate sleeve, positioned along the axial direction of the main spindle, in a forward and backward direction along the axial direction, and having chuck jaws that open and close in accordance with the movement of the intermediate sleeve, and which is detachably attached to the main spindle.

2. The diaphragm-type chuck device according to claim 1, comprising: an adapter disposed inside the main spindle; a push rod disposed inside the adapter and movable in the front-rear direction in accordance with the front-rear movement of the intermediate sleeve; a cap nut detachably attached to the main spindle for holding the adapter and the push rod in a state where they are disposed inside the main spindle and the adapter is not moved in the front-rear direction; a flange disposed in front of the cap nut and fixed to the adapter; a diaphragm disposed in front of the flange, with its outer circumference fixed to the flange and its inner circumference having an end plate portion that elastically deforms when moved forward by the push rod in a forward-moving state; and a plurality of chuck jaws disposed on the front surface of the end plate portion, distributed on a circumference centered on the central axis of the main spindle.

3. The diaphragm-type chuck device according to claim 2, wherein the push rod is always subjected to a biasing force directed backward.

4. The diaphragm-type chuck device according to claim 2 or 3, wherein the forward movement of the push rod is restricted to within the range of elastic deformation of the end plate portion.

5. The diaphragm-type chuck device according to claim 2 or 3, wherein the push rod is separated from the inner circumference when the intermediate sleeve is moved to the rear.

6. The diaphragm-type chuck device according to claim 2, wherein the push rod is formed by dividing it into a collar portion that is movable in the front-rear direction in accordance with the front-rear movement of the intermediate sleeve, and a rod portion that is positioned forward and separated from the collar portion, and moves forward together with the collar portion after the collar portion moves forward and makes contact, and the rod portion is connected to the inner circumference portion and is always subjected to a biasing force directed backward.

7. The diaphragm-type chuck device according to claim 6, wherein an elastic member that constantly applies a rearward biasing force to the rod portion and a spacer are provided between the rod portion and the adapter, and the spacer is interchangeable with other spacers of different lengths in the front-rear direction.

8. The diaphragm-type chuck device according to claim 6, wherein an elastic member and a spacer are provided between the rod portion and the adapter, the spacer being movable in the front-rear direction and being able to be held in the moved position.

9. The diaphragm-type chuck device according to any one of claims 6 to 8, wherein the forward and backward movement of the push rod is restricted to within the range of elastic deformation of the end plate portion.

10. The diaphragm-type chuck device according to any one of claims 1, 2, 3, 6, 7, or 8, wherein the toggle mechanism is attached to and detached from the spindle by replacing a collet chuck device that moves the intermediate sleeve, which is arranged along the axial direction of the spindle, in the front-rear direction along the axial direction, and opens and closes in accordance with the movement of the intermediate sleeve.

11. The diaphragm-type chuck device according to claim 1, wherein the flange has a through hole in its center that penetrates axially, and comprises a cylindrical workpiece receiving member that is combined with the through hole of the flange and has its tip surface on the diaphragm side abut against the end surface of a workpiece to be gripped by the diaphragm, and a cylindrical cover member whose inner circumferential surface on the front end side of the cylinder in the axial direction faces the outer circumferential surface of the flange and whose rear end side in the axial direction is fixed to a non-rotating headstock, and a passage is formed in the cover member, the flange and the workpiece receiving member that communicates from the cover member to the tip surface of the workpiece receiving member.

12. The diaphragm-type chuck device according to claim 11, wherein the workpiece receiving member comprises a cartridge, a workpiece receiving component, and a shaft, the cartridge is formed in a cylindrical shape and fitted into the through hole of the flange, the workpiece receiving component is displaceable in the axial direction between a position in close contact with the tip surface of the cartridge and a position away from the tip surface, a passage is formed between the cartridge and the workpiece receiving component when they are positioned in close contact with each other, and the shaft is coupled to the workpiece receiving component through a cavity inside the cylinder of the cartridge.

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