JP2009220206A - Axial force operating device for chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial force operating device for a chuck using a motor, which is lightweight and compact by operating a clutch with small acting force. <P>SOLUTION: The chuck operating device is provided with: a driving part (the motor) to generate the rotational force with electric power as a drive source; a clutch part for transmitting or shutting the rotational force of the drive part; a deceleration part for reducing the rotational frequency of the drive part; an axial force converting part for converting the rotational power of the deceleration part in the axial direction of a spindle; and a draw pipe for transmitting the force in the axial direction converted by the axial force converting part to the operating shaft. The deceleration part is disposed between the clutch part and the axial force converting part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an axial force operating device capable of generating and operating an axial force necessary for operating a chuck for grasping a workpiece in a lathe or the like, and more particularly to an apparatus including a drive unit using electric power as a drive source.

Most of the axial force operating devices attached to conventional lathes are hydraulically driven, and there has been a strong demand for oilless operation due to energy saving and environmental problems. In response to this, many applications have been filed using a motor driven by electric power as part of the oilless operation.
The structures of these applications are feasible, but require a large space at the rear end of the lathe and attach heavy objects to the spindle so that they are far from the practical stage and do not leave the prototype area. .
Most of them have a structure in which a motor for operating the chuck claw is provided at the rear end portion of the axial force operating device via a clutch (see, for example, Patent Document 1 and Patent Document 2).

JP-A 62-34708 Japanese Patent Laid-Open No. 2001-191203

Those equipped with a clutch at the rear end portion of these axial force operation devices were required to be opened and closed in a state where a large acting force for operating the chuck claw was working, and were a strong clutch having a large acting force. .
The electromagnetic clutch 20 described in the cited document 1 serves to separate the spindle shaft 30 and the induction motor 11 from each other, and prevents the induction motor 11 from being rotated by the rotation of the spindle shaft 30.
The case where the electromagnetic clutch 20 is connected and the claw is moved to grip the workpiece will be described. First, the motor 11 is rotated, and a small torque generated by the rotation is reduced by the speed reducer 13 to be a large torque. The large torque is transmitted to the spline shaft 25 by the clutch 20 and is engaged by the screw nut 30 engaged with the spline shaft 25. , Converted to the axial direction of the spindle 30 and transmitted to the draw bolt 39.
Thus, the torque transmitted by the clutch 20 is increased by the reduction gear 13 from the torque of the motor 11, and the opening and closing of the clutch is performed in a state in which this large torque is applied, so that a strong clutch requiring a large acting force is required. It was.

  The clutch 12 described in the cited document 2 is a clutch that mechanically connects and disconnects the main shaft 1 and the claw feed mechanism 9. That is, when the claw is moved and the workpiece is grasped, the clutch 12 is released, the second motor 10 to which the claw feed mechanism 9 and the rotor are connected is rotated at a required torque, and the chuck claw 3 is moved by the rotational force. It is a structure that grasps the workpiece with the required force. The clutch 12 is a clutch that opens and closes the claw feed mechanism 9 that reciprocates in the axial direction and the main shaft 1, and is coupled to the main shaft 1 for turning while a large axial force is applied to the claw feed mechanism 9. There is a need.

Therefore, this clutch 12 also requires a strong clutch that requires a large acting force, like the clutch 20 described in the above cited reference 1.
For this reason, an axial force operating device using a motor needs a large-capacity clutch, not to mention a motor, and has a large difference from a conventional hydraulically driven axial force operating device in its weight space.
In view of the above problems, an object of the present invention is to provide a lightweight and compact product in a structure in which a small acting force works when a clutch is operated in an axial force operating device for a chuck using a motor.

  In order to achieve the above object, the present invention provides an axial force operating device for a chuck that is attached to the rear end of a main shaft in order to operate a chuck provided at the tip of the main shaft in the axial direction of the rotary shaft, using electric power as a drive source. A drive unit that generates a rotational force, a clutch unit for transmitting or interrupting the rotational force of the drive unit, a deceleration unit that decelerates the rotational speed of the drive unit, and the rotational force of the deceleration unit in the axial direction of the main shaft An axial force conversion unit that converts the axial force converted by the axial force conversion unit to an operation shaft, and the speed reduction unit is provided between the clutch unit and the axial force conversion unit. It is the axial force operation device of the chuck.

  It is an axial force operating device for a chuck in which the clutch portion includes two engagement surfaces that transmit or block rotational force to each of a drive portion and a speed reduction portion.

  The chuck is an axial force operating device having a function of opening and closing the clutch in the axial direction and a function of detecting a phase in the rotational direction.

  The chuck is an axial force operation device in which a rotation shaft of the drive unit is formed coaxially with a rotation shaft of a main shaft.

  The acting force of the axial force conversion unit is an axial force operating device of the chuck that the main shaft bears as an axial reaction force receiver.

  Since the speed reduction part that reduces the rotational speed of the drive part is arranged between the clutch part and the axial force conversion part, when the clutch is operated, a large axial force for tightening the claws or a large torque equivalent thereto is applied to the clutch. Since the clutch can be handled by a small-capacity clutch corresponding to the small torque generated by the motor, space and energy can be saved.

  Since the clutch portion is provided with two engagement surfaces that transmit or cut off the rotational force to each of the drive portion and the speed reduction portion, the engagement surface of the clutch portion is connected to the drive portion after completion of grasping the workpiece by the chuck claw. Between the speed reduction part and the axial force conversion part, the rotational force is interrupted by the engagement surface a of the rotating cylinder, and simultaneously meshes with the opposing engagement surface b of the main body, so that the main shaft, the speed reduction part, and the axial force conversion part are relative to each other. The position is maintained and the grasping locking state can be continued.

  Since the clutch part has a function to open and close in the axial direction and a function to detect the phase in the rotational direction, the relative position between the main spindle body part, the speed reduction part, and the axial force conversion part is a phase difference when in a normal grasping state. Although it is zero, a phase difference is generated in the clutch part when an excessive external force is displaced by acting on the main spindle body, the axial force conversion part, the chuck part, or the like. This phase difference is detected and an abnormal grasping state can be constantly monitored.

  Since the rotating shaft (rotating cylinder) of the driving unit is formed coaxially with the rotating shaft of the main shaft, the driving unit, the clutch unit, the speed reduction unit, and the axial force conversion unit are all configured coaxially with the main shaft. Thus, the transmission mechanism can be simplified, the diameter of the component rotating with the main shaft can be reduced, and a low inertia structure can be obtained. This is given to increase the speed of the spindle.

  Since the main shaft is used as a reaction force receiver in the axial direction of the axial force conversion section, it can be attached to the rear end of the main shaft in the same way as a conventional hydraulic cylinder, and the axial force generated by grasping the workpiece is received by the main shaft. The axial force does not act on the spindle support bearing or the like.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view showing a head stock of a lathe, and shows a part of the head stock in cross section. The chuck 2 is attached to the front end of the headstock of the lathe, and the axial force operating device 3 is attached to the rear end via adapters.
A main shaft 5 supported by a main shaft bearing 4.4 is provided inside the main shaft 1, and a winding 6 constituting a motor for rotating the main shaft is disposed on the outer periphery of the main shaft 5.
The chuck 2 is attached to the front end portion of the main shaft 5 via a front end flange 7, and a workpiece (not shown) is grasped by a chuck claw 8.
In order to move the chuck claw 8, a draw pipe 9 penetrating the inside of the main shaft 5 from the rear end of the chuck 2 is provided, and the chuck claw 8 is opened and closed by reciprocating movement of the draw pipe 9. An axial force operating device 3 for reciprocating the draw pipe 9 via the rear end flange 10 is attached to the rear end of the main shaft 5.

FIG. 2 is a sectional view in which the axial force operating device 3 is attached to the rear end of the main shaft 5.
The axial force operating device 3 includes a main body 11 that rotates together with the main shaft 5, and a drive unit 12 that is provided behind the main body 11 and coaxially with the rotation shaft of the main body 11.
The drive unit (motor) 12 includes a stator 15 provided on a support member 14 attached via a bracket 13 connected to the headstock 1 of a lathe, and a rotatable rotor 16. The rotor 16 has a rotational force. Is transmitted to the clutch portion 17 at the front end face thereof and is connected to a rotating cylinder 18 forming an engagement surface a19.
The clutch portion 17 includes an engagement surface aa20 corresponding to the engagement surface a19 of the rotary cylinder 18, and these two engagement surfaces are opened and closed by an electromagnetic clutch. An engagement surface bb22 corresponding to an engagement surface b21 formed on the rear end surface of the main body 11 of the axial force operating device 3 is provided on the front side of the clutch portion 17, and these two engagement surfaces are the clutch portion 17. It is opened and closed by a biasing elastic member 26 that presses forward.
A sensor 27 for detecting the phase in the rotational direction is provided on the outer periphery of the engagement surface bb22 of the clutch portion 17 and the engagement surface b21 of the main body 11.
Inside the main body 11, there is provided a mechanism for increasing the rotational force of the drive unit 12 disposed coaxially with the main body 11 via a bearing 31 and converting it into an axial force.
The clutch unit 17 is connected to a speed reduction unit 23 that increases the transmitted rotational force, and the speed reduction unit 23 is further coupled to an axial force conversion unit 24. The speed reduction unit 23 converts the high-speed rotation / low torque rotational force of the drive unit 12 into a low rotation / high torque rotational force, and transmits the rotational force to the axial force conversion unit 24. The axial force conversion unit 24 has a structure in which a rotational force is converted into an axial force by a screw mechanism 30 including a nut 28 and a screw shaft 29, and the axial force acts coaxially with the main shaft 5. An elastic body 32 for pressing and fixing the nut 28 in the axial direction is provided on the outer periphery of the nut 28. An operation shaft 25 that moves in the direction of the rotation axis in order to transmit the generated axial force is provided at the center of the axial force conversion unit 24, and is connected to a draw pipe 9 that penetrates the main shaft 5.

The movement of the axial force operation device 3 will be described.
In the axial force operating device 3, when the main shaft 5 is stopped, the rotational force of the driving portion (motor) 12 is engaged with the engaging surface a 19 of the rotary cylinder 18 and the engaging surface aa 20 of the clutch portion 17. Then, it is transmitted to the deceleration unit 23 and the axial force conversion unit 24, converted into an axial force by the axial force conversion unit 24, and opens and closes the claw 8 of the chuck 2 through the draw pipe 9. By this movement, the workpiece is fixed to the chuck, and the main shaft 5 can be rotated.

To rotate the main shaft 5, as shown in FIG. 2, the engagement surface a19 and the engagement surface aa20 are disengaged by the acting force of the urging elastic member 26 that presses the clutch portion 17 forward, and both engagements are performed. A gap a is provided between the surfaces to divide the acting force so that the engagement surface bb22 which is the opposite surface of the clutch portion 17 and the engagement surface b21 provided in the main body 11 are engaged. As a result, the drive unit 12 is separated from the main body 11, and the main body 11 can freely rotate together with the main spindle 5 of the lathe. The biasing elastic member 26 presses the clutch portion 17 against the main body 11 and generates an acting force in a direction in which the engagement surface bb22 meshes with the engagement surface b21 of the main body.
At this time, the engagement surface bb of the clutch portion 17 is coupled to the main body 11 provided continuously to the rear end of the main shaft 5, and the speed reduction portion 23, the axial force conversion portion 24, the operation shaft 25, the draw pipe 9, the chuck 2 and the main shaft front end. The acting force is transmitted to the part, and the grasping and holding state of the workpiece is continued. Therefore, the reaction force of the axial force generated by the axial force conversion unit 24 is applied by the main shaft 5.
If an excessive external force is applied during rotation, the axial force can be compensated by the urging force of the elastic body 32 provided on the outer periphery of the nut 28, thereby enabling safe work.
At this time, the relative position of the chuck claw 8 can be controlled by detecting the phase of the main body 11, that is, the main shaft 5 and the draw pipe 9, by the sensor 27 provided on the outer periphery of the engagement surface b21 of the clutch portion 17. .
In addition, when the main shaft 5 rotates, the sensor 27 detects the difference in the rotation direction phase of the engagement surface b22, thereby converting the axial movement of the draw pipe 9 into the rotation direction, and monitoring the normality or abnormality of the grasping state can be monitored. It can be.

  When the rotation of the main shaft 5 stops with the end of the machining operation, the engagement surface b22 of the clutch portion 17 and the engagement surface b21 of the main body 11 are released, and the engagement surface aa of the clutch portion 17 is the engagement surface on the drive unit 12 side. meshed with a. The drive unit 12 rotates in the direction opposite to that when the workpiece is fixed, and the rotational force is transmitted to the speed reduction unit 23 and the axial force conversion unit 24, and the operation shaft 25 advances and retreats in the direction opposite to the above operation. As a result, the chuck claw 8 opens a workpiece (not shown).

  Although the elastic body 32 is provided on the outer periphery of the nut 28, the same effect can be obtained even if it is provided on the screw shaft 29 side.

It is sectional drawing which attached the chuck | zipper and the axial force operating device of the chuck | zipper to the main axis | shaft of a lathe. It is sectional drawing which attached the axial force operating device to the rear end of the main shaft.

Explanation of symbols

2 Chuck 3 Axial force operation device 5 Main shaft 9 Draw pipe 11 Main body 12 Drive unit 17 Clutch unit 23 Deceleration unit 24 Axial force conversion unit

Claims (5)

An axial force operating device for a chuck that is attached to the rear end of the main shaft in order to operate the chuck provided at the front end of the main shaft in the axial direction of the rotary shaft,
A drive unit that generates a rotational force using electric power as a drive source, a clutch unit for transmitting or interrupting the rotational force of the drive unit, a reduction unit that decelerates the rotational speed of the drive unit, and a rotational force of the reduction unit An axial force conversion unit that converts the axial force into the axial direction of the main shaft, and a draw pipe that transmits the axial force converted by the axial force conversion unit to the operation shaft, and the speed reduction unit includes the clutch unit and the axial force conversion unit A device for operating an axial force of a chuck, wherein the chuck is provided between the two. 2. The chuck's axial force operating device according to claim 1, wherein the clutch portion includes two engaging surfaces that transmit or block rotational force to each of the driving portion and the speed reducing portion. The chuck axial force operating device according to claim 1, wherein the clutch has a function of opening and closing in an axial direction and a function of detecting a phase in a rotational direction. 2. The chuck axial force operating device according to claim 1, wherein the rotation shaft of the drive unit is formed coaxially with the rotation shaft of the main shaft. 5. The chuck axial force operating device according to claim 4, wherein the acting force of the axial force converting portion is applied by the main shaft as a reaction force receiver in the axial direction.

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