JP4807570B2 - Chuck - Google Patents

Description

  According to the present invention, a chuck body is provided with a support hole and a guide hole communicating with an internal space in which a lubricant is put, and a draw bar is slid along the guide hole by movement of a driving member provided in the support hole in the chuck axial direction. The present invention relates to a chuck configured to guide and move a grasping claw at a tip of a draw bar in a clamping direction.

  As a conventional chuck in which a lubricant is sealed in an internal space of a chuck body, a draw down chuck described in Patent Document 1 is known. This drawdown chuck is slidably inserted into a guide hole in the inclined axis direction provided on the front body, which is the front wall of the chuck body, with a gripping claw fixed to the tip, and the rear end of the draw bar is attached to the chuck body. A plunger as a driving member is slidably fitted in a support hole provided in the center of the front cover and the rear cover, which is the rear wall of the chuck body, so as to be movable in the chuck axis direction. The plunger is engaged with the engaging portion of the plunger. In such a drawdown chuck, grease is sealed as a lubricant from a grease nipple provided in the chuck body, and the gap between the guide hole and the draw bar, or between the support hole and the plunger is lubricated by the grease. In such a case where the rear end portion of the draw bar is located in the internal space, the internal volume changes and the internal pressure changes due to the advance and retreat of the draw bar to the internal space, so the lubricant in the internal space is discharged to the outside of the chuck. There is a problem and a problem that the cutting fluid is sucked into the chuck, and there is a problem of rust inside the chuck and a decrease in lubrication due to the cutting fluid. In order to prevent the volume change of the internal space due to the movement of the draw bar and the pressure fluctuation in the internal space, a fitting portion that fits into the support hole of the front body of the plunger (hereinafter referred to as a plunger front fitting portion). ) Is thickened in the fitting portion (hereinafter, referred to as a rear fitting portion of the plunger) to be fitted into the support hole of the rear cover. If the thickness of the rear fitting portion of the plunger is set to a thickness corresponding to “the cross-sectional area of the front fitting portion of the plunger + the cross-sectional area of the rear end portion of the draw bar × the number of draw bars”, the pressure change can be prevented. . However, there is a problem that the rear fitting portion of the plunger becomes too thick, and when the rear fitting portion is retracted, there is a possibility of interference with the spindle hole, and the chuck body may have to be lengthened. For this reason, in the chuck in which the lubricant is filled so that the interior space is not filled with the lubricant so that the volume of air can be increased, the thickness of the rear fitting portion of the plunger is not increased to the above-mentioned thickness, The thickness of the rear fitting portion is compromised by increasing the thickness to some extent, which is one cause of the change in internal pressure due to the advance and retreat of the draw bar.

Japanese Patent No. 3322391

  The present invention prevents a change in volume and a pressure fluctuation caused by a draw bar in an internal space in a chuck in which a lubricant is put in the internal space of the chuck body to lubricate between a guide hole and a draw bar, and between a support hole and a drive member. The present invention also provides a chuck configured to prevent the discharge of lubricant from the inside of the chuck and the ingress of cutting fluid from the outside of the chuck.

According to the present invention, a draw bar having a gripping claw at the tip is slidably inserted into a guide hole provided in the front wall of the chuck body, and the draw bar is inserted into a support hole provided in the center of the front wall and the rear wall of the chuck body. The drive member to be engaged is slidably fitted, the lubricant is put into the inner space formed by closing the rear part of the front wall where the rear center part is depressed, and the draw bar is moved by moving the drive member in the chuck axial direction. In the chuck that is moved forward and backward along the guide hole, an insertion space into which the rear end portion of the draw bar can be inserted is communicated with the outside of the chuck body on the rear wall of the chuck body to support the front wall and the rear wall. Even if the drive member fitting parts that fit into the holes are formed so that their cross-sectional areas have the same size , the draw bar passes through the internal space even if the drive bar moves forward and backward by moving in the chuck axis direction. thing , Characterized in that so as not to change the volume of the inner space.

The front portion of the insertion space constitutes a rear guide hole that is coaxial with the guide hole and reaches the inner space and into which the rear end portion of the draw bar is fitted. The draw bar and the guide hole , and the rear end portion and the rear guide of the draw bar A seal member is provided between the holes and between the drive member and each of the support holes , and the internal space is sealed.

  Further, a closing hole that constitutes an insertion space is provided in the rear wall of the chuck body, and the back part of the closing hole is communicated with the outside of the chuck body by a communication path that opens near the center of the rear wall of the chuck body. It is characterized by that.

  Further, the present invention is a draw down chuck in which a guide hole is provided on the front wall of the chuck body so as to be inclined with respect to the chuck axis.

According to the invention of the present application, the drive member that is provided in the rear wall of the chuck body with the insertion space into which the rear end portion of the draw bar can be inserted communicates with the outside of the chuck body and fits into the support holes of the front wall and the rear wall. the fitting portion, formed as the cross-sectional area of each is the same size, even by advancing and retracting the draw bar in the chuck axis direction movement of the drive member, that the drawbar is inserted through the interior space, the volume of the internal space This prevents the change in the volume of the internal space of the chuck body even when the drawbar moves forward and backward, prevents pressure fluctuations due to air and lubricant in the internal space, and discharges or cuts the lubricant to the outside of the chuck. This prevents the liquid from being sucked into the chuck, that is, improves the sealing performance. In addition, since the insertion space communicates with the outside of the chuck body, the air in the insertion space is supplied to and exhausted from the outside even when the rear end portion of the draw bar moves forward and backward. Fluctuation can be prevented and the drawbar can be moved smoothly. Further, it is not necessary to make the fitting portion of the driving member fitted into the support hole in the rear wall thicker than the fitting portion of the driving member fitted into the support hole in the front wall in order to reduce the volume change. Further, the front portion of the insertion space constitutes a rear guide hole that is coaxial with the guide hole and reaches the inner space and into which the draw bar rear end portion is fitted , and the draw bar, the guide hole , and the draw bar rear end portion, Since a seal member is provided between the rear guide holes and between the drive member and each of the support holes , the internal space is hermetically sealed, so even if the internal space is filled with lubricant, It is not necessary to make the fitting portion of the driving member fitted into the support hole of the rear wall thicker as the interference with the spindle relative to the fitting portion of the driving member to be fitted. For this reason, it is not necessary to lengthen the rear wall of the chuck body by the retreating length of the driving member, and even if the chuck is filled with the lubricant in the internal space, there is an effect that the entire length of the chuck can be shortened. Further, a closing hole that constitutes an insertion space is provided in the rear wall of the chuck body, and the inner part of the closing hole communicates with the outside of the chuck body through a communication path that opens near the center of the rear wall of the chuck body. When the is attached to the spindle, the communication passage is covered with the spindle and communicates with the spindle hole at the center of the spindle, so that chips, cutting fluid, etc. from the outside of the chuck can be prevented from entering the insertion space.

  Embodiments of the present invention will be described with reference to FIGS. As shown in FIG. 1, the drawdown chuck 1 is configured by connecting a front body 3 having a chuck body 2 as a front wall and a rear cover 4 serving as a rear wall. The front body 3 has a recessed central portion on the rear side, and a rear cover 4 closes the rear portion to form an internal space 5. The chuck body 2 is fixed to a front end of a spindle 6 of a machine tool (not shown) with an attachment bolt 8 via an adapter 7. Support holes 9 and 10 are respectively provided in the center portions of the front body 3 and the rear cover 4, and the front fitting portion 12 and the rear fitting portion of the plunger 11 that is a driving member straddle the support holes 9 and 10, respectively. 13 is slidably fitted in the chuck axis L direction. As shown in FIG. 3, the front fitting portion diameter D1 and the front fitting portion 12 and the rear fitting portion 13 of the plunger 11 fitted in the support holes 9 and 10 have the same cross-sectional area. The rear fitting part diameter D2 is the same. Seal members 14 and 14 are fitted between the support hole 9 and the front fitting portion 12 of the front body 3 and between the support hole 10 and the rear fitting portion 13 of the rear cover 4, respectively. A locking portion 15 in the chuck radial direction is formed at an intermediate portion between the front fitting portion 12 and the rear fitting portion 13 of the plunger 11.

  A draw screw 17 is inserted into the stepped hole 16 at the center of the plunger 11, and the draw screw 17 is integrally connected to the plunger 11 by a round nut 18. The draw screw 17 protrudes rearward (leftward in FIG. 1) from the chuck body 2 and is screwed into a connecting rod 19 inserted into a spindle hole 20 at the center of the spindle 6 so as to be behind the spindle 6 of a machine tool (not shown). It is pushed and pulled by driving means such as a rotating cylinder at the end. Reference numeral 21 denotes a ratchet device provided in the plunger 11, and a sphere urged by a spring of the ratchet device 21 is fitted into a hole formed in the round nut 18, positioning the plunger 11 and the round nut 18, and chucking The free rotation of the draw screw 17 relative to the body 2 is restricted, and loosening of the screwing between the draw screw 17 and the connecting rod 19 is prevented.

  The support hole 9 of the front body 3 to which the plunger 11 is fitted is attached with a lid member 24 having a seal member 23 from the front body front surface 22, and the plunger fitted to the support hole 9 of the front body 3. 11 is a closed space 25 between the front fitting portion 12 and the lid member 24. The lid member 24 having the seal member 23 prevents chips and cutting fluid from entering the chuck. The closed space 25 includes a gap 28 formed between the large diameter hole 27 of the stepped hole 16 of the plunger 11 and the draw screw 17, a supply / exhaust passage 29 provided in the rear fitting portion 13 of the plunger 11, and a ratchet device. Through a spring insertion hole 30, a clearance 31 formed between a front end surface of the round nut 18 and a groove in the chuck radial direction provided on the rear end surface of the plunger 11 communicates with the spindle hole 20 outside the chuck. . Thereby, even if the volume of the closed space 25 changes due to the movement of the plunger 11 in the chuck axis direction, air is supplied to and discharged from the outside of the chuck, so that the air is prevented from being compressed and expanded in the closed space 25. 11 moves smoothly.

  The front body 3 is provided with a plurality (three in the present embodiment) of guide holes 32 at equal intervals in the circumferential direction. The guide hole 32 is inclined so as to move away from the chuck axis L as it goes forward (rightward in FIG. 1) with respect to the chuck axis L, and the rear part of the guide hole 32 reaches the inner space 5. In these guide holes 32, a draw bar 34 having a grasping claw 33 at the tip is inserted so as to be slidable in the guide hole axial direction. A dust seal 35 is provided between the front portion of the guide hole 32 and the draw bar 34, and the dust seal 35 is sealed as a seal member. The draw bar 34 is inserted through the internal space 5, and a lock groove 36 is formed in the internal space portion of the draw bar 34, and the lock portion 15 of the plunger 11 is engaged with the lock groove 36. . The rear end portion 34 a of the draw bar 34 is inserted into an insertion space 37 provided in the rear cover 4. The insertion space 37 of the rear cover 4 is constituted by a closing hole 38. The front portion of the closing hole 38 is a rear guide hole 39 that is inclined with respect to the chuck axis L that is coaxial with the guide hole 32 of the front body 3, and reaches the internal space 5. A rear end portion 34 a of the draw bar 34 is slidably fitted in the rear guide hole 39 so as to be slidable in the axial direction of the rear guide hole. A seal member 40 is provided between the rear guide hole 39 and the rear end portion 34 a of the draw bar 34. It has been.

  Further, the rear portion (that is, the rear portion in the chuck axis direction) of the closing hole 38 opens near the center portion of the chuck body 2 and communicates with the outside of the chuck through a gap between the rear fitting portion 13 of the plunger 11 and the rear cover 4. 41 is formed. As shown in FIG. 3, the communication passage 41 communicates with the spindle hole 20 in a state where the chuck 1 is attached to the spindle 6. A dust seal 35 between the guide hole 32 and the draw bar 34, a seal member 40 between the rear guide hole 39 and the rear end portion 34 a of the draw bar 34, the front and rear fitting portions 12 and 13 of the plunger 11, and the support holes 9, The internal space 5 is hermetically sealed by the seal members 14 and 14 between 10 and other seal members provided on the chuck body 2. The internal space 5 is filled with a lubricant and sealed to lubricate the draw bar 34 and the plunger 11.

  As shown in FIGS. 1 and 2, the plunger 11 is moved forward in the chuck axial direction by a rotating cylinder (not shown), the draw bar 34 protrudes, and the gripping claws 33 are opened outward in the chuck radial direction, as shown in FIGS. When the plunger 11 is retracted rearward in the chuck axis direction and the draw bar 34 is retracted and the grasping claw 33 is closed in the chuck radial direction, the rear end portion 34a of the draw bar 34 enters the insertion space 37, and the insertion space Reduce the volume of 37. Then, the air in the insertion space 37 is exhausted from the communication passage 41 to the spindle hole 20 as indicated by the broken line in FIG. 3, and the pressure fluctuation in the insertion space 37 is prevented. At this time, the volume of the internal space 5 does not change, and the pressure of the internal space 5 does not change. In addition, the volume of the closed space 25 is increased by the retreat of the plunger 11, but air is supplied, so that the pressure fluctuation in the closed space 25 is also prevented. On the contrary, when the plunger 11 is moved forward, the volume change and each pressure fluctuation are prevented. At this time, air supply / exhaust from the insertion space 37 and the like is performed in the spindle hole 20, so that it is possible to prevent cutting fluid, chips, and the like from entering the insertion space 37 and the like. Thereby, the chucking operation of the chuck 1 is performed smoothly.

  In the embodiment of the present application, a description has been given of a chuck in which a sealing member is provided between the plunger of the chuck and the respective support holes and the sealed internal space is filled with a lubricant. However, the internal space is sealed with a sealing material. Even if the chuck has air and lubricant in the internal space, the volume of the internal space is not changed, preventing the discharge of lubricant and the suction of cutting fluid due to pressure fluctuations in the internal space. Can do. In addition, although a description has been given of a draw down chuck that is inclined with respect to the chuck axis and includes a draw bar, a draw bar such as a finger chuck described in Japanese Patent No. 3141518 may be implemented in parallel with the chuck axis. .

It is sectional drawing of the chuck | zipper which encloses the lubricant of the state which advanced the plunger of this invention. It is sectional drawing of the chuck | zipper which encloses the lubricant of the state which retracted the plunger. FIG. 3 is an enlarged view of a main part of FIG. 2.

Explanation of symbols

1 Chuck 2 Chuck body 3 Front wall (front body)
4 Rear wall (rear cover)
5 Internal space 9, 10 Support hole 11 Drive member (plunger)
DESCRIPTION OF SYMBOLS 12 Front fitting part 13 Rear fitting part 14 Seal member 32 Guide hole 33 Grasp claw 34 Draw bar 34a Draw bar rear end part 37 Insertion space 38 Closure hole 40 Seal member 41 Communication path

Claims (4)

A draw bar having a gripping claw at the tip is slidably inserted into a guide hole provided in the front wall of the chuck body, and the drive engages with the draw bar in a support hole provided in the center of the front wall and the rear wall of the chuck body. Insert the lubricant into the inner space formed by slidably fitting the members , closing the rear part of the front wall with the rear center part depressed with the rear wall, and moving the drive member in the chuck axial direction to make the draw bar into the guide hole In the chuck that is advanced and retracted along,
An insertion space into which the rear end portion of the draw bar can be inserted into the rear wall of the chuck body is provided so as to communicate with the outside of the chuck body, and the fitting portions of the drive members that fit into the support holes of the front wall and the rear wall are respectively provided. sectional area of the forms to be the same size,
A chuck characterized in that the volume of the internal space is not changed by inserting the draw bar through the internal space even when the draw bar is moved forward and backward by movement of the drive member in the chuck axial direction. The front portion of the insertion space constitutes a rear guide hole that is coaxial with the guide hole and reaches the inner space and into which the rear end portion of the draw bar is fitted. The draw bar and the guide hole , and the rear end portion and the rear guide of the draw bar during the hole, and a sealing member provided between the drive member and each said support hole of the chuck according to claim 1, characterized in that the interior space and a closed state. A closing hole that constitutes an insertion space is provided in the rear wall of the chuck body, and the back of the closing hole is communicated with the outside of the chuck body by a communication path that opens near the center of the rear wall of the chuck body. The chuck according to claim 1 or 2. The chuck according to any one of claims 1 to 3, wherein the chuck is a draw-down chuck in which a guide hole is inclined on the front wall of the chuck body with respect to the chuck axis.

Images