JPH07132402A - Chuck with loosening prevention mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a chuck capable of preventing loosening of a nut from a chuck cylinder. In a chuck for gripping a tool through the chuck cylinder by rotating the nut 22 around the chuck cylinder 16, the nut is provided between the inner peripheral surface of the nut and the outer peripheral surface of the chuck. A wedge member 4 that bites between the inner peripheral surface and the outer peripheral surface by rotating in a loosening direction from a state of being clamped with respect to the chuck cylinder.
0 is a chuck arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck for holding a rotary cutting tool such as a drill or an end mill, and more particularly to a chuck provided with a mechanism for preventing loosening of a nut for tightening a chuck cylinder holding the tool.

[0002]

2. Description of the Related Art Conventionally, as a chuck of this type, a collet is arranged on the inner circumference of a chuck cylinder, the collet and a nut are engaged with each other, and the collet is screwed on the chuck cylinder to rotate the collet on the inner circumference of the chuck cylinder. A collet chuck that slides along the edge of the collet to reduce the diameter of the collet to hold the tool, a ball screw type chuck with a ball screw on the rotating screw, and a needle between the nut and the chuck barrel. There is a so-called needle roller chuck in which a roller is arranged and a chuck cylinder itself is contracted and deformed by the rotation and axial movement of a nut through the needle roller to grip a tool.

[0003]

In recent years, it has become necessary to rotate a cutting tool and, in turn, a chuck at a high speed for reasons such as a demand for speeding up cutting work. The high speed rotation of the chuck may cause vibration of the chuck itself and loosen the tightening of the nut with respect to the chuck cylinder. Further, the tightening of the nut may be loosened due to the inertial force of the nut's own weight at the time of sudden acceleration and sudden stop at the high speed rotation. Particularly, in the case of the ball screw type chuck, the ball screw itself has little friction, so that the nut is easily loosened.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a chuck capable of preventing loosening of a nut from a chuck cylinder.

[0005]

In order to achieve such an object, the present invention provides a chuck for gripping a tool through the chuck cylinder by rotating the nut around the chuck cylinder. Between the inner peripheral surface and the outer peripheral surface of the chuck, the nut rotates between the inner peripheral surface and the outer peripheral surface by rotating in a direction in which the nut is tightened with respect to the chuck cylinder. A wedge member is arranged.

Further, a wedge member is provided between the inner peripheral surface and the outer peripheral surface so as to be movable in a constant range in the circumferential direction,
A play area is formed at both end positions in the circumferential direction of the movement range and a wedge area is formed at the center position, and the wedge member allows rotation of the nut with respect to the chuck cylinder when in the play area and when in the wedge area. It is desirable that the nut is configured to be caught between the inner peripheral surface and the outer peripheral surface to prevent rotation of the nut with respect to the chuck cylinder, and the wedge member is fixed to at least one of the inner peripheral surface and the outer peripheral surface. A storage groove for movably holding it may be formed in the above range, and the play area and the wedge area may be formed between the bottom surface of the storage groove and the other surface facing the storage groove.

Further, it is preferable that the wedge member is configured to move to the play area by applying a constant force to the nut from a state of being in the wedge area, and the wedge member is It may be biased from the play area toward the wedge area.

[0008]

According to the present invention, when the nut is tightened with respect to the chuck cylinder and is rotated in the direction of loosening due to vibration or inertia, the wedge member is provided between the inner peripheral surface of the nut and the outer peripheral surface of the chuck cylinder. By biting, the nut and the chuck cylinder are integrated, and the nut is prevented from rotating in the loosening direction. As a result, loosening of tightening of the nut with respect to the chuck cylinder is prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 shows a first embodiment of the present invention. The chuck body generally indicated by reference numeral 10 is mainly
Machining center and other spindle heads (not shown)
Attached to the taper shank portion 12, which is tapered toward the base end direction, that is, to the left in FIG. 1, the chuck drive flange portion 14 formed following the taper shank portion 12, and the flange portion 14 A chuck cylinder 16 that integrally projects in the distal direction is provided. The chuck used in this embodiment is a so-called ball screw type collet chuck, in which a collet 20 having a tapered outer peripheral surface is arranged on the inner circumference of the chuck cylinder 16, and the collet 20 is rotated on the outer circumference of the chuck cylinder 16. The nut 22 that can be mounted is engaged through the auxiliary nut 24 and the cap 26, and the collet 20 is slid along the inner circumference of the chuck cylinder 16 by the rotational screwing of the nut 22 with respect to the chuck cylinder 16. By this, the collet 20 is reduced in diameter to grip the tool. A spiral groove 27 is formed by the inner peripheral surface of the nut 22 and the outer peripheral surface of the chuck cylinder 16, and a plurality of balls 28 are rotatably fitted in the groove. While the ball 28 rotates, the chuck cylinder 1
The outer circumference of 6 is revolved, whereby the nut 22 is screwed. A second ball 30 is fitted between the auxiliary nut 24 and the collet 20, and the ball 30 integrates the auxiliary nut 24 and the collet 20 with respect to movement in the longitudinal direction. Further, a knurling process 32 is applied to a part of the outer circumference of the nut 22, and a plurality of recesses 34 are formed at appropriate intervals. The recesses 34 are for hooking a spanner (not shown). Reference numeral 36 is an O-ring.

As shown in FIG. 2, which is an exploded perspective view of the nut 22, a storage groove 38 is formed on the base end side of the inner peripheral surface of the nut 22.
3 are formed at appropriate intervals in the circumferential direction, and a cylindrical rolling element 40 is rotatably fitted in each groove 38. As shown in FIG. 3, the groove 38 has a wedge region 42 which is a region where the depth of the groove is relatively shallow.
And play regions 44A and 44B, which are formed on both sides of the wedge region 42 in the circumferential direction and have a deeper groove depth than the wedge region, are continuously formed. The bottom surfaces of the play areas 44A and 44B are formed so that the space between the outer peripheral surface 46 of the chuck cylinder 16 and the outer diameter of the rolling element 40 is the same as or slightly larger than the outer diameter of the rolling element 40 in order to accommodate the rolling element 40 in a freely rotatable manner. There is. The bottom surface of the wedge region 42 has the chuck cylinder 16
The outer peripheral surface 46 of the chuck cylinder 16 is formed so that the gap between the outer peripheral surface 46 of the chuck cylinder 16 and the outer peripheral surface 46 is slightly smaller than the outer diameter of the rolling element 40.

Reference numeral 48 is a washer, and the washer 48 faces the end surface of the rolling element 40 to prevent the rolling element 40 from falling off. A snap ring 50 is mounted on the base end side of the washer 48, and the snap ring 50 prevents the washer 48 from falling off.

Next, the operation of this embodiment will be described. In the state before the tool is gripped by the chuck, the rolling element 40 is located, for example, in the play area 44A on the right side of the chuck body 10 as shown in FIG. Next, when the nut 22 is rotated in the clockwise direction of FIG. 3, that is, the direction of arrow A in order to make the chuck body 10 grasp the tool, the rolling element 4
0 indicates the inner peripheral surface of the play area 44A of the groove 38 and the chuck cylinder 1.
By contacting the outer peripheral surface 46 of 6, the body 6 relatively rotates in the counterclockwise direction while rotating. When the rolling element 40 moves relatively in the counterclockwise direction, the rolling element 40 is positioned in the wedge region 42, and the rolling element 40 is positioned on the bottom surface of the wedge region 42 and the outer peripheral surface of the chuck cylinder 16 as shown in FIG. It bites like a wedge between 46. Next, for example, by hooking a wrench on the recess 34 on the outer periphery of the nut, the nut 2 is further strengthened.
When 2 is rotated clockwise, the nut 22 is elastically deformed in the direction of arrow B in FIG. 4 to release the wedge state of the rolling element 40, and as shown in FIG. Move to area 44B. The rolling element 40 located in the left play area 44B idles, and when the nut 22 is further rotated in the clockwise direction, the nut 22 is screwed in the proximal direction of the chuck body 10, that is, the left direction in FIG. The collet 20 moves in the proximal direction along with the nut 22 to firmly tighten and fix the tool.

Next, when the nut 22 starts to rotate counterclockwise (in the direction of arrow C in FIG. 5) due to vibration or inertial force, the rolling element 40 is brought into contact with the inner peripheral surface of the play area 44B on the left side in FIG. By being in contact with the outer peripheral surface 46 of the chuck cylinder 16, the chuck cylinder 16 rotates relatively while rotating on its own axis. When the rolling element 40 moves relatively clockwise, the rolling element 40 is positioned in the wedge region 42, and as shown in FIG.
A wedge-shaped bite is formed between the bottom surface of the chuck cylinder 16 and the outer peripheral surface 46 of the chuck cylinder 16 to integrate the nut 22 and the chuck cylinder 16. As a result, the nut 22 can be prevented from loosening in tightening the chuck with respect to the tool without further rotating in the counterclockwise direction.

Next, when loosening the nut 22 to remove the tool from the chuck, for example, a spanner is hooked in the recess and the nut 22 is strongly rotated counterclockwise.
The wedged state of the rolling element 40 is released. As a result, the rolling element 40 moves to the play area 44A on the right side while rotating on its own axis. When the nut 22 is further rotated counterclockwise, the tightening of the collet 20 on the tool is released, and the tool can be removed.

As described above, according to the present embodiment, when the nut rotates in the loosening direction from the state in which the chuck holds the tool, the rolling element 40 bites into the wedge region 42 in a wedge shape, so that the chuck is applied to the tool. Looseness can be minimized.

FIG. 6 shows a second embodiment of the present invention. In the groove 38 of the second embodiment, a spring accommodating portion 52 is formed on the left side of the play area 44B on the left side in FIG. 6, and a coil-shaped spring 54 is accommodated in the spring accommodating portion 52. ing. The spring 54 urges the rolling element 40 clockwise, that is, from the play area 44 toward the wedge area 42, so that when the nut 22 is completely tightened, the rolling element 40 is automatically positioned in the wedge area 42. Then, the rolling element 40 is attached to the bottom surface of the wedge region 42 and the chuck cylinder 1.
It becomes a wedge-shaped bite between the outer peripheral surface 46 of 6 and the normal state. Nut 22 and chuck tube 1
6 is almost locked in the loosening direction. Therefore, according to the second embodiment, after tightening the nut 22, the nut 22 does not rotate except when it is rotated by a strong force such as a spanner, and the nut 22 is tightened to the chuck cylinder 16. It does not loosen slightly. Of course, a spring 54 may be further added on the right side of the groove 38. In addition,
Although the coil-shaped spring is used in the present embodiment, the invention is not limited to this and may be a plate-shaped spring, for example.

FIG. 7 shows a third embodiment of the present invention. The third embodiment differs from the second embodiment in that a groove 38 for accommodating the rolling element 40 is formed in the outer peripheral surface 46 of the chuck cylinder 16. Further, in the second embodiment, the rolling element 40 is biased from the play area 44 to the wedge area 42 by the coil spring 54, but in the present embodiment, the rolling element 40 is biased by the rubber 66. There is.

FIG. 8 shows a fourth embodiment of the present invention. The fourth embodiment is different from the first embodiment and is a so-called needle roller chuck. In this needle roller type chuck, a needle roller 56 is arranged between the nut 22 and the chuck cylinder 16, and the chuck cylinder 16 itself is contracted and deformed by rotationally advancing the nut 22 through the needle roller 56, and the tool is It is to be grasped. Reference numeral 58 is a retainer, and the retainer 58 allows the needle roller 5 to move.
6 is rotatably held. Further, reference numeral 60 indicates a sealing material, and 62 indicates a stop ring, which prevents the needle roller 56 from falling off. Also in this embodiment, the rolling element 40 is provided between the inner peripheral surface of the nut and the outer peripheral surface of the chuck cylinder, and has the same operation as that of the above-described embodiments.

Although the rolling element 40 is formed in a cylindrical shape in the above embodiment, it is not limited to this and may have any shape as long as it rolls like a sphere. Further, in the above-described embodiment, the play area and the wedge area are formed by providing the storage groove with unevenness. However, the play area is provided with the use of the storage groove as an ordinary arc-shaped groove. A wedge region may be formed.

[0020]

As described above, according to the present invention, when the nut tightens the chuck cylinder, the rotation of the nut in the direction of loosening the tightening can be stopped. Can be prevented.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a ball screw type collet chuck of the present embodiment.

FIG. 2 is an assembled perspective view of the nut of this embodiment.

3 is a partial cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a cross-sectional view showing a state in which a rolling element bites between a wall surface of a wedge region and an outer peripheral surface of a chuck cylinder.

FIG. 5 is a cross-sectional view showing a state of rolling elements when a tool is gripped by a chuck.

FIG. 6 is a view corresponding to FIG. 3 of the second embodiment of the present invention.

FIG. 7 is a view showing a case where a groove for fitting a rolling element is formed on the outer peripheral side of a chuck cylinder.

FIG. 8 is a partially cutaway side view of a needle roller type chuck according to a fourth embodiment of the present invention.

[Explanation of symbols]

 16 chuck cylinder 22 nut 40 rolling element (wedge member)

Claims (5)

[Claims] 1. In a chuck that grips a tool through the chuck cylinder by rotating the nut around the chuck cylinder, the nut is provided between the inner peripheral surface of the nut and the outer peripheral surface of the chuck. A chuck in which a wedge member is disposed between the inner peripheral surface and the outer peripheral surface by rotating in a loosening direction from a state in which the chuck cylinder is tightened. 2. A wedge member is provided between the inner peripheral surface and the outer peripheral surface so as to be movable in a constant range in the circumferential direction, and play areas are formed at both circumferential ends of the moving range. A wedge area is formed at the center position, and the wedge member is
The nut is configured to allow rotation of the nut with respect to the chuck cylinder when in the play region, and the nut is prevented from rotating with respect to the chuck cylinder by being caught between the inner peripheral surface and the outer peripheral surface when in the wedge region. The described chuck. 3. A storage groove is formed on at least one of the inner peripheral surface and the outer peripheral surface to hold the wedge member so as to be movable within the predetermined range, and the bottom surface of the storage groove and the other of the storage groove facing the storage groove are opposed. The chuck according to claim 2, wherein the play area and the wedge area are formed between the chuck and the surface. 4. The chuck according to claim 3, wherein the wedge member is configured to move to the play area by applying a constant force to the nut from a state of being in the wedge area. 5. The chuck according to claim 4, wherein the wedge member is biased from the play area toward the wedge area.