JPS6133660B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting tool holding device for holding a cutting tool, and more particularly to a holding device that can adjust the position of the cutting edge of the tool.

One type of tool holding device is one in which the position of the cutting tool tip can be adjusted in a direction perpendicular to the center line of rotation by rotating an eccentric sleeve. In this type of holding device, the tool holder is usually fitted into a fitting hole with a circular cross section provided in the holder body via an eccentric sleeve, but in conventional holding devices, the eccentric sleeve is Because it is necessary to be able to slide and rotate within the fitting hole, it is unavoidable that a minute clearance will occur between the eccentric sleeve, the holder body, and the tool holder, and this clearance will accumulate and cause problems in tool retention during cutting. The disadvantage was that the accuracy and, ultimately, the positional accuracy of the cutting edge would be inconsistent, making it difficult to perform high-precision cutting.

Against this background, the present invention was made for the purpose of providing a cutting tool holding device that allows for adjustment of the cutting edge position, does not have minute clearances between functional members, and provides high machining dimensional accuracy. It is something.

To achieve this objective, the holding device according to the present invention includes (a) a first member having a fitting hole with a circular cross section; (b) a first member having a fitting hole having a circular cross section; One or more ball rows consisting of a plurality of balls arranged parallel to the center line, forming a cylindrical shape, and each ball belonging to the ball row protruding slightly from the outer circumferential surface and the inner circumferential surface and moving in the radial direction. an inscribed cylinder and a circumscribed cylinder that inscribe and circumscribe, respectively, all of the ball rows, or all of the ball rows and the ball retainer, are eccentric to each other; (c) a second member having a circular cross-section fitting protrusion that is tightly fitted into the fitting hole through the eccentric ball sleeve; (d) a first member and a second member; and (e) rotating the eccentric ball sleeve by a desired angle between the first member and the second member whose relative rotation is prevented. one of the first member and the second member is attached to a tool attachment part of a machine tool, a cutting tool is attached to the other, and the cutting tool is rotated by rotation of the eccentric ball sleeve. The tool is characterized in that the relative position of the cutting edge to the tool mounting portion of the machine tool is adjustable in a direction perpendicular to the center line of the fitting hole.

In such a tool holding device, the fitting protrusion of the second member is tightly fitted into the fitting hole of the first member through the eccentric ball sleeve, so that the ball row of the eccentric ball sleeve is fitted in the assembled state. Each of the balls belonging to the ball is preloaded and becomes elastically compressed and deformed. In other words, the ball is used as a type of spring member, and the first member, the second member, and the eccentric ball sleeve exert forces on each other due to their compression reaction force (elastic force), so the three members There will be no minute clearance between them, or in other words, no looseness will occur. Therefore, the tool holding precision of the cutting method is extremely high, and the machining dimensions can be maintained with high precision. Moreover, when adjusting the position of the cutting edge, each compressed ball moves along the inner circumferential surface of the fitting hole of the first member, allowing rotation of the eccentric ball sleeve. The position adjustment function is not impaired.

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 are diagrams showing an embodiment in which the present invention is applied to a tool holding device that holds a rotary cutting tool such as a drill, reamer, groove milling cutter, or boring tool, and the reference numerals in each figure 2 indicates the holder body. The holder main body 2 corresponds to a first member and includes a tapered mounting shaft portion 4, and the mounting shaft portion 4 is fitted into a fitting hole of a spillle, which is a tool mounting portion of a rotary cutting machine (not shown). and is tightened by the bolt screwed into the screw hole 6, and the fitting protrusion on the spindle side fits into the fitting groove 8 on the holder main body 2 side shown in FIG. Rotation is prevented.

An end surface 10 of the holder main body 2 opposite to the mounting shaft portion 4 corresponds to a first end surface, and a fitting hole 12 having a circular cross section is formed in the end surface 10. Fitting hole 12
is provided concentrically with the mounting shaft portion 4, and a counterbore hole 14 is formed at the bottom thereof, and a counterbore hole 1 is formed at the bottom thereof.
4, a through hole 16 continuous to the screw hole 16
is provided. A flanged cylindrical ball retainer 18 is fitted into the fitting hole 12 of the holder main body 2 .

As shown in FIGS. 4 and 5, the ball retainer 18 has a center line O ₁ of the outer cylindrical surface (represented as a projected point in FIG. 4; the same applies hereinafter) and an inner cylindrical surface. The center line O ₂ of the cylindrical surface is eccentric by a dimension α, and the wall of the ball retainer 18 has symmetrical positions with respect to the plane including the center lines O ₁ and O ₂ , that is, the inner circumferential surface and the outer circumferential surface. A row of groups of ball holding holes 22 each having a circular cross section are provided at positions equiangularly spaced apart (approximately 60 degrees in this embodiment) in both directions from the closest point. As is clear from FIG. 5, the ball holding holes 22 in each row are aligned with the center lines O ₁ and O ₂
at equal intervals in a direction parallel to the ball cage 1
A plurality of holes (six in this embodiment) are provided to penetrate in the semi-longitudinal direction from the inner circumferential surface to the outer circumferential surface of the ball retainer 8, and have a hole diameter slightly larger than the wall thickness of the ball retainer 18 at that portion. As shown in FIG. 3, one steel ball 24 is housed in each of the ball holding holes 22 in each row, so that the holder main body 2
Six balls 24 are arranged parallel to the center line of the hole 12 along the inner peripheral surface of the fitting hole 12, and these balls 24 constitute two rows of balls. An eccentric ball sleeve 26 is constituted by the ball rows and the ball retainer 18 that holds the ball rows. An eccentric ball sleeve means that the entire sleeve with the balls has an eccentric shape.

The balls 24 are all of the same size and have a diameter slightly larger than the length of the ball holding hole 22, while the ball retainer 18 has each ball 24 belonging to the ball row slightly separated from the outer and inner peripheral surfaces. It holds each row of balls so that they can protrude (for example, about 0.05 mm to 0.003 mm),
It has an outer diameter dimension that allows it to fit into the fitting hole 12 of the holder main body 2 with high precision. As is clear from FIG. 6, which schematically shows the eccentric ball sleeve 26, the inscribed cylinder C ₁ is inscribed in all of the two ball rows consisting of the plurality of balls 24 and the ball retainer 18, and similarly Assuming a circumscribed cylinder C ₂ , their center lines O ₁ ′ and O ₂ ′ are offset from each other by an eccentric amount α ′, and the characteristic parts are exaggerated in the figure for ease of understanding. However, in the case of this embodiment, the eccentricity α' is closer to the center line of the inner and outer peripheral surfaces of the ball retainer 18 itself.
This is slightly smaller than the eccentricity α of O ₁ and O ₂ . As shown in FIG. 1 etc., one end of the ball retainer 18, in other words, the eccentric ball sleeve 2
A circular flange 28 is formed radially outward at one end of the 6, and this flange 28 makes surface contact with the opening end surface of the fitting hole 12, that is, the end surface 10 of the holder body 2, thereby preventing eccentricity. The amount of fitting of the ball sleeve 26 is defined.

A socket 30 is fitted into the fitting hole 12 of the holder body 2 via an eccentric ball sleeve 26. The socket 30 is connected to the holder main body 2 which is the first member.
A fitting protrusion with a circular cross section, which serves as a second member for the body, and is provided at the center of the end surface 32 (this corresponds to the second end surface) of the circular base and protrudes at right angles to the end surface 32. 34,
If you change your perspective, you can see the flange 36 facing outward in the radial direction.
It has a cylindrical shape with one end. socket 3
The outer diameter of the fitting protrusion 34 of No. 0 is slightly larger than the diameter of the inscribed cylinder C ₁ of the eccentric ball sleeve 26 shown in FIG. The fitting protrusion 34 is tightly fitted to the inside of the eccentric ball sleeve 26, that is, the inscribed cylinder _C1 , and the fitting hole 1 of the holder body 2 is tightly fitted.
2, while the socket flange 36 seats on the flange 28 of the eccentric ball sleeve 26, thereby defining the amount of fit of the socket 30.

When the socket fitting protrusion 34 is tightly fitted, each ball 24 belonging to the ball row is elastically compressed and deformed between its outer circumferential surface and the inner circumferential surface of the fitting hole 12. Due to the elastic (spring) action of the balls 24 functioning as a body, the socket fitting protrusion 34 is actively urged in the direction of the resultant force of the ball elastic forces, and the ball retainer 18
is kept pressed against the inner circumferential surface of the Therefore, action and reaction forces act between the holder main body 2, the eccentric ball sleeve 26, and the socket 30, so that there is no clearance between these three members, and a stable state is maintained without mutual play. .
In addition, when tightly fitting the socket fitting protrusion 34, it is also possible to fit the eccentric ball sleeve 26 into the fitting hole 12 of the holder main body 2 and then push the socket 36 into the sleeve 26 by an appropriate method. Then, attach the socket 30 to the eccentric ball sleeve 26 in advance.
It is also possible to press fit them into the fitting hole 12 after fitting them.

A tool holding hole 38 with a bottom is formed in the socket 30 from the end face on the flange 36 side concentrically with the axis thereof, and a shaft portion of a boring tool or the like is inserted into the holding hole 38, and the screw hole 40 is inserted into the holding hole 38. The intermediate flange of the tool is held down by a set screw that is tightened into the socket 30, and the intermediate flange of the tool is tightened into the screw hole 42 against the flange 36 of the socket 30 with the tool main body having the cutting edge protruding a certain distance from the socket 30. It is concluded by.

A spring receiving member 44 is fixed by a bolt 46 to the end surface of the socket 30 on the opposite side from the side where the tool holding hole 38 is provided. A disc spring 48 is installed between the spring receiving member 44 and the holder body 2 with a certain compression preload, and its elastic force causes the socket 30 to fit into the fitting hole 12 of the holder body 2. It is biased in the direction of being pulled in. In other words, the disc spring 48 biases the end surface 32 of the socket 30 and the end surface 10 of the holder body 2 through the flange 28 of the eccentric ball sleeve 26 so as to bring them into close contact with each other. It serves as a means.

A U-shaped notch 50 is formed in the end surface 32 of the socket 30 radially inward from the outer periphery, while a pin hole is formed in the end surface 10 of the holder body 2 parallel to the center line of the fitting hole 12. 52 are provided,
A pin 54 press-fitted into the pin hole 52 passes through an arc-shaped elongated hole 56 provided in the flange 28 of the eccentric ball sleeve 26 and is fitted into the U-shaped notch 50. Pin 54 as shown in FIG.
are engaged with almost no gap between the mutually parallel side walls of the notch 50, and their engagement prevents relative rotation of the holder body 2 and the socket 30 about the center line of the fitting hole 12. cage, pin 54
The notch 50 constitutes relative rotation prevention means. On the other hand, the arc-shaped elongated hole 56 of the eccentric ball sleeve 26 is formed along a substantially semicircular arc with a width slightly wider than the diameter of the pin 54, and therefore the holder is prevented from relative rotation. Between the body 2 and the socket 30, rotation of the eccentric ball sleeve 26 is permitted within an angular range of approximately 180 degrees from one end of the elongated hole 56 to the other end.

A wrench engagement hole 58 is provided on the outer peripheral surface of the flange 28 of the eccentric ball sleeve 26 to rotate the eccentric ball sleeve 26 by a desired angle, as shown in FIG. It functions as a means for rotating the sleeve 26. As shown in FIG. 7, a large number of scale lines 60 are engraved on the outer peripheral surface of the flange 36 of the socket 30, while reference lines 62 are engraved on the outer peripheral surface of the sleeve flange 28. This indicates the amount of rotation of the eccentric ball sleeve 26.

In the tool holding device as described above, as schematically shown in FIG. The retainer 18 can be held with no clearance in the fitting hole 12 of the holder main body 2 while receiving the elastic force of each ball 24 at three locations at approximately equal angular intervals with respect to the inner circumferential surface of the retainer 18, so that the holding accuracy can be improved. Very good. Furthermore, when a particularly large cutting load is applied to the tool during cutting, each of the balls 24 is further elastically compressed and deformed, collaborating with the inner and outer peripheral surfaces of the ball retainer 18 in the vicinity of the balls 24. Since the tool can receive the cutting load while in surface contact, the positioning accuracy of the tool tip is high even during heavy cutting, and highly accurate machining dimensions can be obtained.

When it is necessary to adjust the position of the cutting tool to compensate for wear on the cutting tool, or to replace the cutting blade or the tool itself, insert the wrench into the wrench engagement hole 58 and check the scale line 60, etc. However, if the eccentric ball sleeve 26 is rotated by the necessary angle, the relative position of the cutting edge relative to the center line of the rotary cutting machine can be adjusted based on the eccentricity of the internal cylinder C ₁ and the external cylinder C ₂ . The fitting hole 12 of the main body 2 is displaced in a direction perpendicular to the center line, and its cutting radius is appropriately adjusted. When the eccentric ball sleeve 26 is rotated, each ball 24 belonging to the ball row and the ball retainer 18 are rotated against the holder main body 2.
The eccentric ball sleeve 26 is rotated while sliding between the two and the socket 30, but since the contact area of the eccentric ball sleeve 26 with the two is small, the operating force required to overcome the frictional force is not very large. Note that the inner circumferential surface of the fitting hole 12 of the holder body 2, the outer circumferential surface of the socket 30, the inner and outer circumferential surfaces of the eccentric ball sleeve 26, etc. are surface hardened by appropriate means such as carburizing. It is desirable to be present.

Next, another embodiment of the present invention will be described based on FIGS. 8 to 10.

In this embodiment, the eccentric ball sleeve 64 does not have a radially outwardly directed flange, so that the end face 10 of the holder body 2 and the end face 32 of the socket 30
and the disc spring 48 directly without going through a flange.
are held in close contact by the elastic force of Instead, worm gear teeth 68 are formed on the outer peripheral surface of the ball retainer 66 over the entire circumference in the circumferential direction, so that the ball retainer 66 functions as a worm wheel, as shown in FIG. The balls 24 are arranged so as to avoid the portion where the worm gear teeth 68 are formed. On the other hand, the holder body 2 is provided with a worm housing hole 70, and the center line of the hole 70 is aligned with the fitting hole 12 of the body 2.
The accommodating hole 70 and the fitting hole 12 intersect at right angles to the center line of the accommodating hole 70 and the fitting hole 12 are communicated with each other by partially interfering with each other, and a worm 72 is accommodated in the accommodating hole 70. The worm 70 has worm teeth 74
A threaded sleeve 76 with a
The worm shaft 78 is fitted into the fitting hole 12 by a set screw 80 etc. so that it cannot rotate relative to the worm shaft 78 . The worm shaft 78 is rotatably held with its axial movement restricted in a substantially tangential direction, and a wrench engagement hole 86 is formed in the head 84 of the worm shaft 78 . and,
The worm 72, the teeth 74, and the teeth 68 of the ball retainer 66 are engaged with each other to form a worm gear device, and in this embodiment, the gear device serves as a rotating means for rotating the eccentric ball sleeve 64, and serves as a wrench. When the worm 72 is rotated through the wrench that is engaged with the engagement hole 86, each rotation causes the eccentric ball sleeve 64 to move slightly between the socket 30 and the holder body 2, which are prevented from relative rotation. It can be rotated by an angle. Since the other parts are the same as those in the previous embodiment, the same reference numerals are used in the drawings and explanations thereof will be omitted.

In the tool holding device configured in this way, the same effects as those of the above embodiment can be obtained, and in addition,
There is an advantage that the amount of rotation of the eccentric ball sleeve 64 can be controlled more precisely, and the precision of adjusting the position of the cutting edge is improved, and there is also an effect that the eccentric ball sleeve 64 can be rotated with a small rotational operation force.

Although two embodiments of the present invention have been described above, they are literally illustrative, and the present invention can be implemented in other embodiments. For example, in the previous embodiments, one ball was accommodated in each of the plurality of ball holding holes provided in the ball retainer, but an appropriate number of ball holding holes may be provided in the shape of an elongated hole or a notch. , two or more balls may be accommodated therein to form a ball row. As for the balls themselves, although those made of steel were used as an example in the above embodiments, they are not necessarily limited to this; if they can exhibit the above-mentioned elastic retention function, they may be made of, for example, hard synthetic resin. It is also possible to adopt the following. In this case, the amount of protrusion on one side is preferably 0.5 to 0.05 mm.

Further, although two ball rows were formed in the above embodiment, a corresponding effect can be obtained even if there is only one ball row, and on the other hand, three or more ball rows can also be formed. In that case, the diameters of the balls belonging to each ball row are changed, and the balls belonging to each row are gradually changed from the ball row having relatively large diameter balls to the ball row having relatively small diameter balls. As a result, the inscribed cylinder and the circumscribed cylinder, which are inscribed and circumscribed, respectively, in all of these ball rows are made eccentric to each other. In other words, in order to make both cylinders eccentric, it is possible not only to make the inner circumferential surface and the outer circumferential surface of the ball retainer eccentric to each other, but also to change the ball diameters of the plurality of ball rows.

Furthermore, in the embodiment described above, a fitting hole was provided in the holder body to be attached to the machine tool, and a fitting protrusion was provided in the socket to which the cutting tool was attached.
Conversely, it is also possible to provide a fitting protrusion on the holder body and a fitting hole in the socket into which the protrusion fits. In this case, the holder body corresponds to the second member, and the socket corresponds to the first member.

Furthermore, if a clamping device as shown in FIG. 11 is added to the embodiments shown in FIGS. 8 to 10, not only the tool holding accuracy but also the tool holding rigidity will be increased, and the process will be improved from rough machining to semi-finishing machining. It is possible to perform finishing processing in one step. In the figure, 90 is a clamp shaft, and the socket 30
extends through the bottom wall of. A nut 92 is screwed onto the tip of the clamp shaft 90, and a disc spring 94 is inserted between the nut 92 and the bottom wall of the socket 30.
is installed. The rear end of the clamp shaft 90 is fitted into the clamp shaft hole 96 of the holder body 2, and a round hole 98 of a constant depth is provided in the rear end in a direction perpendicular to the axis. Round hole 9
A first tapered hole 100 is formed in which the inner diameter gradually decreases from the bottom of the hole 8 toward the back. From the opposite side of this round hole 98, at a position perpendicular to the axis and backward from the first tapered hole portion 100, that is, at a position eccentric a certain distance toward the rear end of the clamp shaft 90, the inner diameter gradually decreases from the outside toward the back. A second tapered hole 102 is formed, and a connecting hole 104 is provided to connect the first tapered hole 100 and the second tapered hole 102. This connection hole 1
04 is arranged between the center line of the first tapered hole section 100 and the center line of the second tapered hole section 102, and the center line of the connecting hole 104
The center line of is located on a plane passing through the axis of the clamp shaft 90.

The holder body 2 has the clamp shaft hole 9
A through hole 110 is provided perpendicularly to the axis of 6, and a screw hole portion 112 having a right-handed thread is formed in this through hole 10, and a clamp screw 114 is screwed into this screw hole portion 112. ing. The clamp screw 114 has a right-handed threaded portion 116 that is screwed into the threaded hole 112, a straight portion 118 having a diameter slightly smaller than the root diameter of the right-handed threaded portion 116, and a tapered shaft portion 120 whose diameter gradually decreases toward the tip. , a left-handed threaded portion 122 having a left-handed thread, and a clamp screw 11
4, the diameter of the tapered shaft portion 120 is smaller than the diameter of the first tapered hole portion 100, and the taper angles thereof are the same.

An extruded metal 12 is inserted into the through hole 110 of the holder body.
6 is fitted in a slidable and rotatable manner, and this extrusion metal 126 is formed with a tapered shaft portion 128 that functions to extrude the clamp shaft 90. The tapered shaft portion 128 and the second tapered hole portion 102 have the same taper angle. A screw hole 130 having a left-hand thread is formed in the extrusion metal 126, and the left-hand thread portion 122 of the clamp screw 114 is screwed into this screw hole 130, and is tightened by a lock screw 132 to be integral with the clamp screw 114. It is designed to rotate. Clamp screw 114
When the clamp screw 114 is rotated clockwise through the hexagonal hole 124, the clamp screw 114 advances, and the tapered shaft portion 120 pushes the rear portion of the inner surface of the first tapered hole portion 100 of the clamp shaft 90 backward, and the clamp shaft 9
0, and conversely rotate the clamp screw 114 counterclockwise, the extrusion metal 126 rotates and moves, and the tapered shaft part 128 moves into the second tapered hole part 1.
02 inner surface is pushed forward, and the clamp shaft 90 is pushed out. In this case, the extrusion metal 126 and the clamp screw 114 are screwed together with a left-handed thread, so when the clamp screw 114 is rotated counterclockwise during use, the extrusion metal 126 can be easily tightened, thereby preventing loosening.

In a tool holding device equipped with such a clamp device, the position of the cutting edge is adjusted by pushing out the clamp shaft 90 and rotating the eccentric ball sleeve 64 while weakening the spring force of the disc spring 94.
Thereafter, by retracting the clamp shaft 90 and increasing the spring force of the disc spring 94, the end surface 10 of the holder main body 2 and the end surface 32 of the socket 30 can be brought into strong contact. At that time, socket 3
0 and the holder main body 2 move slightly relative to each other in the direction of the center line of the fitting hole 12 of the main body 2, but there is no change in the position of the cutting edge in the direction perpendicular to the center line, so it is different from immediately after adjusting the cutting edge position. A highly accurate clamping condition can be obtained.

In addition, although specific explanations are omitted, it goes without saying that the present invention can be embodied in various improvements and modifications without departing from the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a cutting tool holding device according to an embodiment of the present invention, and FIG. 2 is a front view,
FIG. 3 is a - sectional view in FIG. 2. FIG. 4 is a front view of the ball retainer of this device,
FIG. 5 is a - sectional view in FIG. 4. FIG. 6 is an explanatory view schematically showing the eccentric ball sleeve in the present device, and FIG. 7 is a perspective view showing the assembled state of the socket of the present device and the ball retainer. FIG. 8 is a longitudinal cross-sectional view showing another embodiment of the present invention, FIG. 9 is a partially cutaway front view thereof, and FIG. 10 is a cross-sectional view taken from FIG. 9. FIG. 11 is a longitudinal sectional view showing the main parts of another embodiment of the present invention. 2: Holder main body (first member), 12: Fitting hole,
18, 66: Ball retainer, 22: Ball holding hole, 24: Ball, 26, 64: Eccentric ball sleeve, 28: Flange, 30: Socket (second member), 32: End face (second end face), 34: Fitting synapse,
48, 94: Belleville spring, 50: Notch, 54: Pin,
56: Elongated hole, 68: Worm gear teeth, 72: Worm, 78: Worm shaft, 90: Clamp shaft, 114: Clamp screw.

Claims (1)

[Scope of Claims] 1. A first member having a fitting hole with a circular cross section; and a row of balls arranged along the inner peripheral surface of the fitting hole and parallel to the center line of the hole. The above-mentioned ball row is provided with a ball retainer having a cylindrical shape and holding the ball row so that each ball belonging to the ball row protrudes slightly from an outer peripheral surface and an inner peripheral surface and can move in a radial direction. an eccentric ball sleeve in which an inscribed cylinder and a circumscribed cylinder inscribed and circumscribed, respectively, in all of the rows or in all of the ball rows and the ball retainer are eccentric to each other; a second fitting protrusion with a circular cross section that is tightly fitted into the fitting hole;
a member; a relative rotation prevention means for preventing relative rotation of the first member and the second member about the center line of the fitting hole; and a relative rotation prevention means for preventing the relative rotation of the first member and the second member. a rotating means for rotating the eccentric ball sleeve by a desired angle between the first and second members, and one of the first member and the second member is attached to a tool attachment part of a machine tool, and a cutting tool is attached to the other. and the relative position of the cutting edge of the cutting tool with respect to the tool mounting portion of the machine tool can be adjusted in a direction perpendicular to the center line of the fitting hole by rotation of the eccentric ball sleeve. Cutting tool holding device with adjustable cutting edge position.