JP4378813B2 - Drawdown chuck - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, a draw bar having a gripping claw at a tip is slidably guided in a guide hole in an inclined axis direction inclined with respect to a chuck axis provided on a chuck body, and a driving member at the center of the chuck body is moved in the chuck axis direction. In particular, the draw bar is moved forward and backward along the guide hole in the direction of the inclined axis. The present invention relates to a drawdown chuck in which the drawbar is prevented from rotating.
[0002]
[Prior art]
A cylindrical drawbar (formed from a round bar) is slidably guided in a guide hole formed in the chuck body in the direction of the inclined axis. A rear end portion of the draw bar projects into the inner space of the chuck body, and an engagement surface perpendicular to the inclined axis of the guide hole is formed at the rear end portion. In addition, a locking surface perpendicular to the inclined axis of the guide hole is formed on the outer periphery of the drive member that is moved in the chuck axis direction in the inner space. A draw-down chuck is known in which the engaging surface and the engaging surface are engaged with each other and the drive member is retracted in the axial direction so that the draw bar is pulled obliquely rearward and grasped while pulling the workpiece with a grasping claw at the tip.
[0003]
In such a drawdown chuck, the draw bar has a cylindrical shape. The draw bar is engaged to prevent the draw bar from rotating about the tilt axis of the guide hole. Examples of such are disclosed in, for example, Japanese Patent No. 2820996 and Japanese Utility Model Laid-Open No. 57-193304. In Japanese Utility Model Laid-Open No. 57-193304, an appropriate space is provided between the rotation stop bolts engaged with the rotation stop grooves, and the draw bar can be slightly rotated.
[0004]
[Problems to be solved by the invention]
In the above-mentioned conventional one, since a non-rotating bolt, that is, a round pin-shaped anti-rotation member is engaged with the anti-rotation groove, when the anti-rotation is made, the side surface of the anti-rotation groove in the circumferential direction of the draw bar and the anti-rotation member Due to the external force acting between the side surface of the anti-rotation groove and the anti-rotation member, the relative deformation of the anti-rotation groove and the anti-rotation member is large, and the draw bar tilts the guide hole according to the deformation. Rotating around the axis, the jaw at the tip of the draw bar cannot move correctly toward the center of the chuck. There was an easy problem. In addition, in Japanese Utility Model Publication No. 57-193304, the drawbar can be rotated slightly, and when grasping a deformed object or material, it can be securely gripped according to the work, but as in finishing processing There is a problem that the accuracy decreases when it is desired to grasp with high accuracy.
An object of the present invention is to provide a drawdown chuck having high durability and high grasping accuracy.
[0005]
In the present application, a drive member is provided in the inner space of the chuck body so as to be movable in the chuck axis direction, and a draw bar having a gripping claw at the tip is slidably guided in a guide hole in the tilt axis direction provided in the chuck body, A draw-down chuck in which the draw bar is moved forward and backward along the guide hole in the direction of the inclined axis by the axial movement of the drive member, and a detent provided on the outer peripheral surface of the draw bar and the chuck body In a draw down chuck that engages a member and prevents the drawbar from rotating, the rotation preventing member includes a mounting member provided with a screw portion on the outer periphery and an insertion hole on the inner end portion, a rotation prevention key, and a rotation prevention key. and a mounting member configured from a fixing screw for attaching together, the engaging end of said detent grooves is in detent key, drawbars circumferential detent groove An anti-rotation surface that abuts the surface when sliding on the side surface facing the engagement end is formed, and an attachment member having an outer end opposite to the engagement end of the anti-rotation key is inserted into the insertion hole. It is characterized by being screwed onto the outer peripheral wall (claim 1). According to this, the relative deformation between the non-rotating groove and the non-rotating member is extremely small as compared with the conventional one per line, and the gripping claw at the tip of the draw bar can be accurately moved toward the center of the chuck. In addition to being able to grasp, the surface pressure per surface can be lowered, and the anti-rotation groove and the anti-rotation member are not easily worn.
[0007]
Good Mashiku is the drawbar, the tilting axis parallel to the grease hole is provided, as well as opening the rear end of the grease holes in the interior space, constituting the grease passage communicating the other end of the grease holes in the detent groove The anti-rotation groove is configured such that the spaces before and after the anti-rotation member are connected to each other (Claim 2 ). According to this, since the grease hole is inclined, the centrifugal force directly acts on the grease that has entered the grease hole, so that the grease can move smoothly along the grease hole, and the slide between the draw bar and the guide hole The part can be reliably lubricated with grease. Further, since the non-rotating groove also serves as a part of the grease passage and the grease passage is formed only by forming the grease hole in the draw bar, the labor for processing is reduced.
[0008]
A lubricating groove shallower than the anti-rotation groove was formed continuously to the anti-rotation groove. (Claim 3 ) According to this, the lubricating area is further increased and the lubricating function is improved.
[0009]
The drive member has a locking surface orthogonal to the inclination axis of the draw bar, and the draw bar is provided with an engagement surface orthogonal to the inclination axis of the draw bar, and the draw bar is advanced and retracted by locking the engagement surface and the locking surface. To do. (Claim 4 )
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, a chuck body 1 is configured by connecting a front body 2 and a back plate 3. The back plate 3 is attached to the front end of the main shaft (not shown). The front body 2 has a recessed central portion on the rear side, and the back space is closed by the back plate 3 to form an inner space 4. Further, the front body 2 has projecting portions 2b projecting forward from the front wall 2a at three locations in the circumferential direction that form guide holes 20 described later (FIGS. 1 and 2). The front and rear shaft portions of the drive member (draw sleeve) 7 are supported by the support holes 5 and 6 formed at the chuck centers of the front body 2 and the back plate 3 so as to be slidable in the chuck axis direction. An intermediate portion in the chuck axial direction of the drive member 7 is a disc portion 8, and the disc portion 8 has notches in the radial direction shown in FIG. 3 at three locations at equal intervals (120 degree intervals) in the circumferential direction. A portion 9 is formed, and both side portions of the notch portion 9 are locking portions 10. The front and rear surfaces of the locking portion 10 in the chuck axis direction are locking surfaces 10a and 10b that are orthogonal to an inclined axis CL1 of a guide hole 20 described later. The disk portion 8 between the adjacent notch portions 9 and the notch portion 9 is formed with a detent hole 11 parallel to the chuck axis, and is provided between the front body 2 and the back plate 3. The stopper pin 12 is inserted so as to be movable in the axial direction. A screw member 13 is integrally screwed to the rear end portion of the drive member 7, and a draw screw 14 is inserted into the center of the screw member 13, and is integrally connected to the screw member 13, that is, the drive member 7 by a nut 15. . The draw screw 14 is pushed and pulled by a rotating cylinder (not shown) at the rear end of the main spindle of the machine tool.
[0012]
The front body 2 passes through the front wall 2a from the projecting portions 2b projecting at three positions at equal intervals in the circumferential direction corresponding to the notches 9, and is rearward with respect to the chuck axis CL (FIG. 1). The guide hole 20 in the direction of the inclined axis CL1 that is inclined so as to approach the chuck axis CL toward the left side) is provided so as to reach the inner space 4. In each guide hole 20, the entire inner circumference of the hole is a guide surface in the front wall 2a portion, but only the radially outer side surface is a guide surface in the protruding portion 2b portion. In each guide hole 20, a draw bar 21 formed of a round bar having a circular cross section is guided so as to be slidable along the inclined axis CL1.
[0013]
The leading end of the draw bar 21 is provided with a grasping claw 22 on the inner side in the chuck radial direction. A rear end portion of the draw bar 21 projects into the inner space 4. The protruding portion is formed in a narrow diameter portion 23 that enters the cutout portion 9 of the drive member 7 and an engagement portion 24 that extends from the narrow diameter portion 23 and is hooked on the locking surface 10 b of the locking portion 10. The engaging part 24 has a flat surface 25 with upper and lower parts cut away so as to match the diameter of the small-diameter part 23, and the front surface in the chuck axial direction of the engaging part 24 is connected to the inclined axis CL 1 of the guide hole 20. It is formed in the orthogonal engagement surface 24a, and the engagement surface 24a is slidably locked with the locking surface 10b. Further, the end surface of the draw bar 21 from which the small-diameter portion 23 protrudes is also an engagement surface 29 orthogonal to the inclined axis CL1 of the guide hole 20, and the engagement surface 29 is slidably locked with the locking surface 10a. .
[0014]
The draw bar 21 is assembled in the state of FIG. 3 in which the left and right side walls of the notch 9 and the flat surface 25 are orthogonal to each other. In the assembled state, the draw bar 21 is disposed on the outer peripheral surface in the chuck radial direction as shown in FIG. A detent groove 26 having a predetermined length is formed along the tilt axis CL1. The anti-rotation groove 26 also serves as a grease passage 31 as will be described later. A lubrication groove 27 that is shallower than the rotation prevention groove 26 is formed on the further front side of the rotation prevention groove 26. The anti-rotation groove 26 is provided on the outer peripheral wall of the front body 2 and is fitted with a leading end portion of an anti-rotation member 28 protruding toward the inside of the guide hole 20 to prevent the draw bar 21 from rotating in the direction of the tilt axis CL1. It is only movable.
[0015]
The anti-rotation member 28 includes an anti-rotation key 33, an attachment member 34, and a fixing screw 35 as shown in FIG. The anti-rotation key 33 protrudes toward the inside of the guide hole 20, and the engagement end 33 a, which is a tip portion fitted into the anti-rotation groove 26, has the engagement end 33 a in the circumferential direction of the draw bar 21 of the anti-rotation groove 26. Anti-rotation surfaces 33b and 33b are formed in sliding contact with the opposite left and right side surfaces (left and right side surfaces in FIG. 5) 26a and 26a, respectively. A screw hole 33c into which the fixing screw 35 is screwed is formed at the outer end of the rotation stop key 33 opposite to the engagement end 33a (on the chuck radial direction outer side).
[0016]
The inner end portion of the mounting member 34 on the inner side in the chuck radial direction is provided with a threaded portion 34a on the outer periphery, and the outer end portion on the opposite side (the outer side in the chuck radial direction) of the locking key 33 is inserted. An insertion hole 34b is provided. The outer end portion of the mounting member 34 on the outer side in the chuck radial direction is larger in diameter than the inner end portion, and the outer end portion is provided with a receiving hole 34c for receiving the head of the fixing screw 35 via the washer 36. It has been. In addition, as shown in FIG. 6, a hexagonal hole 34d having a hexagonal cross section communicating with the insertion hole 34b and the accommodation hole 34c is formed, and the hexagonal hole 34d is used to screw the front body 2 with a known hexagon wrench. To do.
[0017]
The anti-rotation member 28 engages the left and right anti-rotation surfaces 33 b and 33 b of the engagement end 33 a of the anti-rotation key 33 with the left and right side surfaces 26 a and 26 a of the anti-rotation groove 26, and prevents the rotation of the insertion hole 34 b of the attachment member 34. The outer end of the key 33 is inserted, and the attachment member 34 is screwed onto the outer peripheral wall of the front body 2. Then, the locking key 33 and the mounting member 34 are integrated with the fixing screw 35 via the washer 36, and the locking key 33 is fixed to the front body 2. Since the anti-rotation key 33 is inserted into the anti-rotation groove 26 and then attached by the front body 2 attachment member 34, the anti-rotation member 28 is easily assembled. In the state where the rotation prevention key 33 and the mounting member 34 are integrated, a gap is formed between the bottom surface 26b of the rotation prevention groove 26 and the tip of the rotation prevention key 33, and the rotation prevention key 33 of the rotation prevention groove 26 is formed. The spaces before and after the gap are connected, so that the grease can enter the entire rotation prevention groove 26 that also serves as the grease passage 3. A gap is also formed between the rotation preventing member 28 and the outer peripheral surface of the draw bar 21.
[0018]
In the assembled state, the draw bar 21 is forward (relative to the chuck axis CL) from the outer side in the chuck radial direction with respect to the narrow diameter portion 23 of the engagement surface 29 toward the rear end portion of the detent groove 26. A grease hole 30 that is inclined so as to be away from the chuck axis CL is formed toward the right side in FIG. The grease hole 30 is parallel to the tilt axis CL1 of the draw bar 21. The rear end portion (one end portion) of the grease hole 30 opens directly into the inner space 4, and the front end portion (the other end portion) of the grease hole 30 opens into the anti-rotation groove 26, and thus the grease hole 30 The inner space 4 communicates with the anti-rotation groove 26 and the lubrication groove 27, and the grease hole 30, the anti-rotation groove 26 and the lubrication groove 27 lead the sliding portion between the draw bar 21 and the guide hole 20 into the inner space 4. A grease passage 31 for supplying the grease is formed. The front body 2 is provided with a grease nipple 32 for enclosing grease in the inner space 4.
[0019]
Prior to use, grease is sealed in the inner space 4 from the grease nipple 32. Part of the enclosed grease also enters the grease hole 30. When the draw screw 14 is pulled to the rear of the chuck axis from the state of FIG. 1, the drive member 7 is retracted, the engaging portion 24 is hooked on the engaging portion 10, and the draw bar 21 is retracted along the inclined axis, thereby grasping the grasping claw 22. The workpiece W is moved inward in the radial direction while being retracted, and the workpiece W is grasped while being pulled toward the front surface of the chuck. When the workpiece W is grasped, the spindle is rotated and the chuck is rotated. By this rotation, centrifugal force acts on the grease inside the chuck. Then, since the grease hole 30 is inclined obliquely outward to the grease entering the grease hole 30, a force directed forward in the chuck axis direction acts by the centrifugal force, and the grease is prevented from rotating. It is pushed out smoothly toward the groove 26. The extruded grease is pressed against the inner surface of the guide hole 20 facing the rotation stop groove 26 by centrifugal force, lubricates the portion, and further moves toward the lubrication groove 27 so as to face the lubrication groove 27. Lubricate the inner surface of the hole 20.
[0020]
On the other hand, a force that moves toward the outside in the chuck radial direction by a centrifugal force is also applied to the grease in the inner space 20. Since the rear end of the grease hole 30 opens in the end surface 29 oblique to the chuck axis, the grease in the inner space 4 is pushed into the grease hole 30 from the opening of the grease hole 30, and thus the inner space 4. The grease is supplied to the grease hole 30 little by little, and the supplied grease receives the action of the centrifugal force due to the chuck rotation as described above and is sent to the detent groove 26 and the lubrication groove 27, so that the grease lubrication is extremely smooth. To be done.
[0021]
Further, when the workpiece is grasped, the draw bar 21 is prevented from rotating in the circumferential direction of the draw bar 21 due to the sliding contact between the detent surface 33b and the side surface 26a. At this time, since the rotation preventing surface 33b and the side surface 26a are in contact with each other, even if the rotational force in the circumferential direction of the draw bar 21 acts, the relative deformation between the rotation preventing surface 33b and the side surface 26a is small, and the draw bar 21 The gripping claws 22 are accurately moved toward the chuck center and the workpiece W can be grasped with high accuracy. Further, since the anti-rotation surface 33b and the side surface 26a are in contact with each other, the surface pressure can be reduced, so that the anti-rotation member 28 and the anti-rotation groove 26 are not easily worn and durability is improved.
[0022]
【The invention's effect】
As described above, in the present invention, since the anti-rotation surface formed on the anti-rotation member and the side surface of the anti-rotation groove are in sliding contact with each other, the conventional anti-rotation member and anti-rotation groove are in contact with the line. In comparison, the relative deformation between the anti-rotation member and the anti-rotation groove when grasping the workpiece is reduced, the forming center direction of each grasping claw is directed to the center of the chuck, and the grasping accuracy is increased. Further, since the anti-rotation member and the anti-rotation groove come into contact with each other, wear of the anti-rotation member and the anti-rotation groove is reduced, and durability is improved. In addition, since the grease hole is inclined outward, the centrifugal force directly acts on the grease that has entered the grease hole, so that the grease can smoothly move along the grease hole, and the sliding between the draw bar and the guide hole can be performed. The grease can be reliably fed to the moving part, and the sliding part can be smoothly lubricated. Further, the rotation preventing groove necessary for the draw bar of the drawdown chuck also serves as a part of the grease passage, and the grease passage is formed only by forming the grease hole in the draw bar. Furthermore, since the lubrication groove shallower than the rotation prevention groove is formed continuously to the rotation prevention groove, the lubrication area is further increased and the lubrication function is improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a drawdown chuck of the present application.
FIG. 2 is a front view of a drawdown chuck.
FIG. 3 is a view taken along the line III in FIG. 1;
4 is a view taken along the line IV in FIG. 1, showing a partly broken chuck body. FIG.
FIG. 5 is a cross-sectional view taken along line VV in FIG.
6 is a cross-sectional view taken along line VI-VI in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Chuck body 4 Inner space 7 Drive member 10a, 10b Locking surface 20 Guide hole 21 Draw bar 22 Grasp claw 24a, 29 Engagement surface 26 Anti-rotation groove 26a Side surface 27 Lubrication groove 28 Anti-rotation member 30 Grease hole 31 Grease passage 33 Around Lock key 33a Engagement end 33b Non-rotating surface 34 Mounting member 35 Fixing screw

Claims (4)

A drive member is provided in the inner space of the chuck body so as to be movable in the chuck axis direction, and a guide bar in the tilt axis direction provided in the chuck body is slidably guided to a draw bar having a grasping claw at the tip, and the drive member A draw down chuck in which the draw bar is moved forward and backward along the guide hole in the direction of the inclined axis by moving in the axial direction of In a draw down chuck that engages to prevent the draw bar from rotating, the rotation preventing member includes an attachment member having a screw portion on the outer periphery and an insertion hole on the inner end portion, a rotation prevention key, a rotation prevention key, and an attachment member. was composed of a fixing screw for mounting integrally, the detent key engagement end of the detent groove, and engaging end drawbars circumferential detent groove A locking member is formed which contacts the surface when it is slid in contact with the opposite side surface, and a mounting member in which the outer end opposite to the engaging end of the locking key is inserted into the insertion hole is screwed onto the outer peripheral wall of the chuck body. A drawdown chuck characterized by the combination.   The draw bar is provided with a grease hole parallel to the inclined axis, the rear end of the grease hole is opened in the inner space, and the other end of the grease hole is communicated with a rotation prevention groove to form a grease passage. The drawdown chuck according to claim 1, wherein the front and rear spaces sandwiching the anti-rotation member are connected.   The drawdown chuck according to claim 2, wherein a lubrication groove shallower than the rotation prevention groove is formed continuously with the rotation prevention groove.   The drive member has a locking surface orthogonal to the inclination axis of the draw bar, and the draw bar is provided with an engagement surface orthogonal to the inclination axis of the draw bar, and the draw bar is advanced and retracted by locking the engagement surface and the locking surface. The drawdown chuck according to any one of claims 1 to 3.

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