Cylinder built-in chuck device

Abstract

To provide a cylinder built-in chuck device suppressing temperature rise of air in a device body.SOLUTION: A cylinder built-in chuck device includes a device body that is equipped with a chuck claw on a front surface side gripping a workpiece, a single-acting cylinder that is assembled in the device body so as to operate the chuck claw, and an auxiliary air chamber that is formed in the device body communicated to a spring chamber into which a spring configuring the single-acting cylinder is inserted, through an air channel. When gripping the workpiece, the single-acting cylinder assembled in the device body actuates and the spring is compressed to decrease volume of the spring chamber. However, the spring chamber communicates with the auxiliary air chamber in the device body through the air channel, so that temperature rise of air due to compression can be suppressed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a chuck device with a built-in cylinder, which is provided with a cylinder that is operated by air pressure inside the device body. [Background technology]

[0002] Machine tools such as lathes are equipped with chuck devices that are capable of gripping workpieces. Such chuck devices require a mechanism to operate the chuck jaws, and some mechanisms use a drawbar to transmit the output from an external actuator to operate the chuck jaws. When gripping a workpiece with a strong force, an appropriate actuator is used. On the other hand, some chuck devices have a cylinder inside, and the output from the cylinder operates the chuck jaws. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 60-103591 Summary of the Invention [Problem to be solved by the invention]

[0004] A chuck device with a built-in cylinder, which has a cylinder installed inside the device body, uses fluid pressure, and the cylinder structure and flow paths for supplying operating air and the like are formed inside the device body. Because the chuck device is incorporated as part of a machine tool, there is a limit to its size, which also imposes restrictions on the cylinder structure and the like formed inside the device body. When the cylinder and air flow path assembled in such a narrow space are repeatedly extended and retracted by the piston, the air is also repeatedly compressed, causing a temperature rise. This temperature rise has a negative impact on the operation of the cylinder.

[0005] Therefore, in order to solve the above problem, an object of the present invention is to provide a chuck device with a built-in cylinder that suppresses the temperature rise of the air inside the device body. [Means for solving the problem]

[0006] The cylinder-integrated chuck device according to the present invention comprises a device body having chuck jaws on the front side for gripping a workpiece, a single-acting cylinder incorporated in the device body for operating the chuck jaws, and an auxiliary air chamber formed in the device body that communicates via an air flow path with a spring chamber into which a spring constituting the single-acting cylinder is inserted. Two sets of the single-acting cylinder and the auxiliary air chamber are formed in the device body, and the single-acting cylinder and the auxiliary air chamber are alternately arranged at intervals of 90 degrees in the circumferential direction. . Another chuck device with a built-in cylinder according to the present invention comprises a device body having chuck jaws on the front side for gripping a workpiece, a single-acting cylinder incorporated in the device body for operating the chuck jaws, and an auxiliary air chamber formed in the device body and communicating via an air flow path with a spring chamber into which a spring constituting the single-acting cylinder is inserted, wherein the device body is formed by stacking disk-shaped blocks and comprises a cylinder block in which a cylinder portion of the single-acting cylinder in which a piston slides and the auxiliary air chamber are formed, and a flow path block in which an air flow path is formed that communicates the spring chamber constituting a part of the single-acting cylinder with the auxiliary air chamber. . [Effects of the Invention]

[0007] According to the above-mentioned configuration, the workpiece is gripped by the chuck jaws provided on the front side of the device body by the operation of a single-acting cylinder incorporated in the device body, and at that time, the volume of the spring chamber is reduced by compressing the spring, but since the spring chamber is connected to the auxiliary air chamber in the device body via an air flow path, it is possible to suppress the temperature rise of the air due to compression. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of a chuck device with a built-in cylinder. [Figure 2] FIG. 2 is a view of a cylinder block constituting the device body of the cylinder-integrated chuck device, viewed from the front side of the device in the axial direction. [Figure 3] FIG. 2 is a view of a flow path block that constitutes the device body of the chuck device with a built-in cylinder, viewed from the front side of the device in the axial direction. [Figure 4] FIG. 1 is a cross-sectional view showing a conventional chuck device of a closed spring chamber type. [Figure 5] FIG. 10 is a cross-sectional view showing a conventional chuck device provided with a relief hole. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a chuck device with a built-in cylinder according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the chuck device with a built-in cylinder of this embodiment. This chuck device with a built-in cylinder (hereinafter simply referred to as "chuck device") 1 is a spindle chuck for a machine tool, and uses a collet chuck as the main structure for gripping a workpiece, and is additionally provided with an auxiliary chuck for stably gripping the workpiece. This chuck device 1 uses a cylinder, which is a feature of the present invention, as the auxiliary chuck. Therefore, FIG. 1 specifically shows the configuration of the auxiliary chuck, and omits the structure of the collet chuck to avoid complicating the drawing. The collet chuck has a general configuration.

[0010] The spindle device of the machine tool has a spindle 3 rotatably mounted on a cylindrical headstock, with a chuck device 1 attached to the tip of the spindle 3. The spindle device is configured so that the output of the telescopic actuator is transmitted to the collet chuck via a drive transmission rod 5 that passes through the inside of the spindle 3, thereby gripping and releasing the workpiece. The chuck device 1 of this embodiment rotates integrally with the spindle 3 through the rotation control of the spindle motor, and the collet chuck imparts rotation to the workpiece clamped in the chuck device 1, thereby performing cutting and other processes.

[0011] There are cases where the workpiece held by the chucking device 1 has a long axial dimension, for example, and the holding of the collet chuck alone does not provide stability during machining. Therefore, in order to accommodate such workpieces, the chucking device 1 is provided with an auxiliary chuck 7 that holds the workpiece in the axial direction from the front side of the chuck (right side in the drawing). In the chucking device 1, the collet chuck, which is the main chuck, is located in the center, and the auxiliary chuck 7 is located radially outside the collet chuck, and is configured symmetrically at two locations 180° apart around the rotation axis O, taking into account balance during rotation.

[0012] The auxiliary chucks 7 provided at two locations have the same structure, and are configured so that the chuck jaws 11 rotate while also moving axially to hold down the workpiece from the front side. The auxiliary chuck 7 has a rotating shaft 12 inserted inside the device main body 9, and the chuck jaws 11 are screwed to the tip of the rotating shaft 12 so that they are perpendicular to the tip. A single-acting cylinder 13 is also configured inside the device main body 9, and the rotating shaft 12 is rotatably connected coaxially to a piston rod protruding from the piston 21.

[0013] The single-acting cylinder 13 is configured such that the biasing force of the spring 22 acts in the direction in which the chuck jaws 11 press down on the workpiece. Therefore, inside the single-acting cylinder 13, the front side of the chuck device 1 relative to the piston 21 forms a spring chamber 23, and the opposite side across the piston 21 forms a pressurizing chamber 24, to which an air flow path 25 is connected. The air flow path 25 communicates with a communication path that passes through the inside of the drive transmission rod 5, and the supply and discharge of operating air to the pressurizing chamber 24 can be switched via a selector valve.

[0014] In the auxiliary chuck 7, the spring 22 is compressed by supplying operating air to the pressurizing chamber 25, and the spring 22 is expanded by discharging the operating air, causing the rotating shaft 12 integrated with the piston 21 to move in the axial direction. A lead groove 26 cut obliquely relative to the axis is formed on the side of the rotating shaft 12, and the tip of an action pin 27 fixed to the device body 9 is inserted into the lead groove 26. Therefore, the angle of rotation of the rotating shaft 12 relative to its axial movement is set by the inclination of the lead groove 26.

[0015] Incidentally, in the auxiliary chuck 7 formed by the single-acting cylinder 13, operating air is supplied to the pressure chamber 24 every time the workpiece gripped by the chuck device 1 is released. Then, in the spring chamber 23 where the spring 22 is compressed, the volume of the spring chamber 23 decreases and the air inside is compressed. Here, FIG. 4 is a cross-sectional view showing a conventional chuck device equipped with an auxiliary chuck like this embodiment. In this chuck device 100, when the spring 111 is compressed, the air in the spring chamber 113, which has no escape route, is compressed and generates compression heat.

[0016] When a workpiece is repeatedly machined on a machine tool, the auxiliary chuck 101 also operates repeatedly, and each time the volume of the spring chamber 113 decreases, compressing the air and causing a temperature rise. Because the single-acting cylinder 110 has a large stroke, the compression rate of the air in the spring chamber 113 increases, and the resulting temperature rise impairs the movement of the piston 115. Therefore, it is desirable to have a structure that allows the air in the spring chamber to escape. Figure 5 is a cross-sectional view showing a conventional chuck device of the same type as this embodiment, which is provided with an escape hole.

[0017] In this chuck device 200, a relief hole 212 is formed so that the spring chamber 211 of the auxiliary chuck 201 communicates with the outside (atmosphere). Therefore, even if the spring 213 is compressed when releasing the gripped workpiece, the air in the spring chamber 211 is released to the outside through the relief hole 212 and is not compressed. However, when the spring 213 expands and the spring chamber 211 expands, it draws in outside air, and in particular in an environment where chips and coolant are flying around, such as a machine tool, the air sucked in can cause problems such as rusting of the spring 213.

[0018] Therefore, in the chuck device 1 of this embodiment, an auxiliary air chamber 28 is formed which is in communication with the spring chamber 23, as shown in Fig. 1. The spring chamber 23 becomes a space integrated with the auxiliary air chamber 28, so that the apparent volume of the spring chamber 23 is increased, and the compression rate of the air when the spring 22 is compressed is kept low. Here, Fig. 2 is a view of a cylinder block 32 which constitutes the device main body 9, as seen in the axial direction from the front side of the device (the right side of Fig. 1), and Fig. 3 is a view of a flow path block 33 which constitutes the device main body 9, as seen in the axial direction from the front side of the device.

[0019] The device main body 9 is constructed by stacking disk-shaped blocks. The device main body 9 has a base block 31 fixed to the spindle 3, and a cylinder block 32 and a flow path block 33 stacked on the base block 31 to form an integrated unit. Furthermore, the device main body 9 has main body blocks 34 and 35 stacked on the flow path block 33. Note that these configurations are shown for the purpose of explaining the auxiliary chuck 7, and the details that make up the collet chuck are omitted.

[0020] The cylinder block 32 is formed with two cylinder portions 41 in which the piston 21 of the single-acting cylinder 13 slides, and two auxiliary air chambers 28. The cylinder portions 41 and the auxiliary air chambers 28 are both circular holes with bottoms, and are spaced apart by 90° in the circumferential direction. interval In the cylinder portion 41, the two auxiliary chucks 7 are arranged at symmetrical positions in consideration of the weight balance of the rotating chuck device 1, and the auxiliary air chamber 28 is configured as an empty space in consideration of the relationship with the collet chuck and the like as well as the balance during rotation.

[0021] The flow path block 33 is formed with a through spring insertion hole 43 which, together with the cylinder portion 41, constitutes the spring chamber 23. The spring insertion hole 43 is formed at a position overlapping the cylinder portion 41 and has a smaller diameter than the cylinder portion 41. Therefore, a step is formed in the spring chamber 23 as shown in FIG. 1, and the position where the piston 21 hits the flow path block 33 is the stroke end. Therefore, in the conventional chuck device 100, air is compressed in a space corresponding to the small-diameter spring insertion hole 43.

[0022] In this embodiment, the flow path block 33 has an air flow path 45 formed therein, which communicates with the spring insertion hole 43. The opening of the air flow path 45 is blocked by a stopper 46, and the air flow path 45 is isolated from the outside. A branch portion 47 is formed in the air flow path 45 at a position overlapping with the auxiliary air chamber 28, and the spring chamber 23 and the auxiliary air chamber 28 communicate with each other to form a single space. The auxiliary air chamber 28 is formed with a volume approximately 1 to 1.5 times the maximum volume of the spring chamber 23, so that it can be formed inside the narrow interior of the device main body 9, while obtaining the effect of suppressing temperature rise by reducing the compression rate.

[0023] Next, the workpiece is held down in the chucking device 1 by the action of the biasing force of the spring 22, as shown in Figure 1. In the single-acting cylinder 13, when the piston 21 is biased and moves to the left side of the drawing, the rotating shaft 12 is retracted accordingly. At that time, the fixed action pin 27 is guided by the lead groove 26, causing the rotating shaft 12 to rotate by a certain angle, and the chuck jaws 11 at the tip end thereof turn. As a result, the workpiece held by the collet chuck is pressed down in the axial direction by the auxiliary chuck 7.

[0024] On the other hand, when the workpiece is released after machining is completed, operating air is supplied to the pressurizing chamber 25, and the pressure of the air causes the piston 21 to move against the biasing force of the spring 22. The spring 22 is compressed and the volume of the spring chamber 23 decreases, but the air inside the spring chamber 23 flows through the air flow path 45 into the auxiliary air chamber 28. Then, the piston 21 of the single-acting cylinder 13 moves to the right in FIG. 1, the lead groove 26 is guided by the action pin 27, and the chuck jaws 11 rotate to the retracted position. The collet chuck is also released, and the workpiece is removed from the chucking device 1.

[0025] Therefore, in this embodiment, even if the volume of the spring chamber 23 is reduced, the compression rate of the air is kept low in the series of spaces including the auxiliary air chamber 28. Therefore, even if changes that reduce the volume of the spring chamber 23 are repeatedly made, it is possible to suppress an increase in the temperature of the air and prevent a deterioration in the operating conditions of the single-acting cylinder 13. Furthermore, because the spaces of the spring chamber 23, the auxiliary air chamber 28, and the air flow rate 45 are sealed, it is possible to use in environments where coolant, etc., splashes, such as machine tools.

[0026] Although one embodiment of the present invention has been described above, the present invention is not limited to this and various modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, the chuck device 1 is described as being provided with an auxiliary chuck 7 that assists the gripping by the collet chuck, but the cylinder-incorporated chuck device is not particularly limited to this. [Explanation of symbols]

[0027] 1...Chuck device 7...Auxiliary chuck 9...Device body 11...Chuck jaws 13...Single-acting cylinder 21...Piston 22...Spring 23...Spring chamber 24...Pressure chamber 25...Air flow path 28...Auxiliary air chamber 32...Cylinder block 33...Flow path block

Claims

1. A device body having chuck jaws on the front side for gripping the workpiece; a single-acting cylinder incorporated in the device body for operating the chuck jaws; an auxiliary air chamber formed in the device body and communicating with a spring chamber, into which a spring constituting the single-acting cylinder is inserted, via an air flow path; and The chuck device has two sets of the single-acting cylinder and the auxiliary air chamber formed in the device body, and the single-acting cylinder and the auxiliary air chamber are alternately arranged at 90 degree intervals in the circumferential direction.

2. A device body having chuck jaws on the front side that grip the workpiece; a single-acting cylinder incorporated in the device body for operating the chuck jaws; an auxiliary air chamber formed in the device body and communicating with a spring chamber, into which a spring constituting the single-acting cylinder is inserted, via an air flow path; and The device body is configured by stacking disk-shaped blocks, and includes a cylinder block in which a cylinder portion of the single-acting cylinder in which a piston slides and the auxiliary air chamber are formed, and a flow path block in which an air flow path communicating a spring chamber constituting a part of the single-acting cylinder and the auxiliary air chamber is formed.

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