JPS5823522Y2 - double chuck - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of a chuck for a rotary cutting tool, and in particular, a double-structured chuck that allows the cutting tool to be easily attached and detached, has a strong grip, and prevents the cutting tool from generating self-excited vibration during cutting. It provides:

In conventional chucks, the collet is tightened and released by moving the taper member in and out.

At this time, the taper member is moved in the axial direction by appropriate means, but this movement requires considerable friction on the sliding surface between the collet and the taper member, or on the sliding surface between the taper member and the main body. This caused a considerable amount of force to be tightened to the point where the knife could be securely gripped.

In other words, conventional chucks require the application of considerable force to produce the necessary holding force, and are therefore not easy to operate.

Reliably and quickly tightening or releasing the collet is extremely important when handling chucks, especially for multi-axis machines that use multiple chucks to grip the cutting tool and simultaneously perform drilling or cutting operations. Grinding machines (drilling machines, milling machines, etc. used in automobile manufacturing processes, etc.) are particularly desired to have cutting tools that can be easily attached and detached and that they can be held securely.

In view of the above-mentioned circumstances, it is extremely important to make collet tightening and unwinding operations easier when handling collets.

An example of a device having such characteristics is a chuck tube into which a target tool or an adapter for holding the tool is inserted, the outer peripheral surface of which is formed into a tapered shape, and a rotary tube into which the object tool is fitted and the chuck tube are connected. In between, a large number of needle rollers whose axes do not intersect with the axis but have an appropriate inclination angle with respect to the axis are arranged and distributed over a wide range, and when the rotating cylinder is rotated, these needle rollers rotate on their own axis. Japanese Utility Model Publication No. 41-23987 proposes a chuck in which the chuck barrel is contracted or restored by spirally rotating.

This chuck has excellent operability in that a needle roller is arranged on the tapered surface of the outer periphery of the holder body, and the needle roller is rotated and spirally revolved by operating a rotating cylinder to generate the required tightening force. It was temporary.

The clamping force of the chuck tube (collet) formed in the holder body of the chuck is obtained by rotating the rotary tube, but in order to transform this rotational force into tightening force, the chuck tube must be rotated. In order to make the collet easier to deform, a thinner part is required, and the collet ends up being thinner overall.

Torque and moment act simultaneously on the base (neck) where the collet is connected to the main body during cutting, but if the collet is made thin as described above, it will not be able to withstand the large force. Become.

In order to avoid this drawback, if the collet wall is made thicker, it becomes difficult to contract in the radial direction, which requires gripping the blade when operating the rotary tube, and the rotation of the rotary tube immediately reduces the inner diameter of the adapter (or chuck tube). Since the tightening force does not decrease, the tightening effect becomes inferior.

In the conventional chuck mentioned above, since there is rolling friction between the rotary tube and the collet, the rotary tube rotates lightly and provides the necessary gripping force to the collet, but the neck part is thin and self-excited vibrations occur. As a result, the structure had to be extremely weak.

Therefore, the cutting depth and cutting speed (or cutting amount) are inevitably limited, and heavy cutting and machining that would cause a large moment to act on the base of the collet had to be avoided.

As mentioned above, although the collet of the chuck described in Japanese Utility Model Publication No. 41-23987 has good tightness, the neck is weak and the resistance to moment is extremely small, resulting in self-excited vibration during cutting. Because of this, the cutting load cannot be increased, and the precision of the cut surface tends to deteriorate, which is an essential problem.

When considering desirable characteristics of a chuck, the following are required.

A) The collet can be tightened lightly and easily.

To this end, it is best to develop the conventional structure based on the above-mentioned conventional structure in which roller bearings are arranged on the tapered surface and pressing force is applied by a wedge ring.

In addition, in order to make it easier to grip (grasp) the cutting tool,
The thickness of the collet is preferably as thin as possible.

B) It must have enough strength to withstand the torque and moment during cutting.

Although the collet itself transmits the torque required for cutting, it is structurally difficult to maintain the collet's lateral wobbling.

Therefore, a structure is needed to hold the collet against lateral wobbling.

Preventing the collet from lateral wobbling can prevent self-excited vibrations that occur during cutting, especially during heavy cutting, making it possible to create a structure suitable for heavy cutting, and improving grinding accuracy.

C) It must be easy to handle, small, and durable.

To enable a collet to be easily tightened and released, and to be attached to a multi-axis cutting device.

This means that it can withstand long-term use and maintain high precision during that time.In particular, it is important that it does not easily generate self-excited vibrations because it prevents the cutting tool from loosening and prevents wear on the parts that make up the chuck. It is.

The present invention eliminates the drawbacks of the prior art and provides a chuck that has the three characteristics described above.

In order to achieve the above object, the present invention supports a wedge ring via a needle roller bearing that rotates (rotates and revolves) in a spiral manner on the tapered surface of the outer circumference of the collet, and further supports the cylindrical surface of the outer surface of the wedge ring. This device is characterized in that a gripping sleeve is positioned via a roller bearing, and one end of the gripping sleeve is fixed to the main body.

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

The figure shows the right half of the chuck according to the present invention cut away from the center line, in which a gripping sleeve 2 is integrally provided at the tip of a tapered shank 10 of a main body 1.

The inner surface of this gripping sleeve 2 is provided with parallel cylindrical holes, into which a needle roller bearing 3 is fitted, and through this bearing 3 a wedge ring 6 is provided.

This wedge ring 6 is composed of a cylindrical body, and has a parallel cylindrical surface on the outer peripheral surface, and a tapered surface 5 whose inner diameter is enlarged on the side facing the tapered shank 10 on the inner peripheral surface, and its cross section is wedge-shaped. is formed.

A collet 9 having a taper corresponding to the taper of the wedge ring 6 on the outer surface is provided on the inner surface of the tapered surface 5 of the wedge ring 6 via a needle roller bearing 1.

In this embodiment, the main body 1 and the collet 9 are constructed separately and fixed by appropriate means to prevent movement of both, but in an actual chuck, consideration should be given to manufacturing and material aspects. The collet 9 may be integrated with the main body 1 or may be separate from the main body 1.

The outer circumferential surface of the gripping sleeve 2 is tapered with a step 12.

An O-ring 13 is held in the large diameter portion by a circumferential groove 14.

A female screw 15 is provided in the small diameter portion, and a step 16 is provided at the tip of the female screw 15.
It is formed thinly.

A wedge operating ring 4 having an inner surface shape corresponding to the outer peripheral surface of the gripping sleeve 2 is fitted and screwed into the gripping sleeve 2.

The wedge operation ring 4 is in close contact with the outer peripheral surfaces of the large diameter portion and the smallest diameter portion of the gripping sleeve 2 so as to be able to slide thereon.

The O-ring 13 provided on the gripping sleeve 2 slides against the inner peripheral surface of the wedge operation ring 4 to form a duster.

The front end of the wedge operation ring 4 is provided with an internal gear-shaped unevenness 17.

A needle roller bearing 3 held by a cylindrical retainer 3' is fitted and deployed on the inner peripheral surface of the gripping sleeve 2.

A wedge ring 6 is fitted inside this needle roller bearing 3.

The wedge ring 6 has a gear-shaped pawl 17' and a flange 18 at its front end.
It has

The pawl 17' engages with the ink-null gear-shaped unevenness 17 of the wedge ring 4, and the flange 18 is fixedly fixed to the front surface of the unevenness 17 by countersunk screws.

In this way, the wedge ring 6 is fitted into the gripping sleeve 2 so that it can rotate back and forth together with the wedge operating ring 4.

The inner surface of the wedge ring 6 has a tapered surface 5 so that the depth is thinner.
It is formed.

A needle roller bearing 7, which is held by a trumpet-shaped cylindrical retainer 7', is further fitted into the tapered surface 5.

A collet 9 is fitted inside the needle roller bearing 7 and is axially integrated with the main body 1 at the back of the holding hole 11.

The collet 9 has a cylindrical shape with a tapered surface 8 on the outer surface,
It is engaged with the main body 1 by the engaging rib 19 at the back, so that it cannot escape naturally, and it is designed to sufficiently transmit the torque necessary for cutting.

Thus, the tapered surface 8 corresponds to the tapered surface 5 of the wedge ring 6.

In the figure, 20 is a keyway for transmitting the power of the drive shaft, 21 is an oil seal, and 22 is a wrench operation hole for tightening and releasing.

In the embodiment of the present invention, the taper shank 10 and the clamping sleeve 2 are machined from the same material, but if the collet 9 and the taper shank 10 are machined as a single piece, the clamping sleeve 2 is machined from the taper shank. It can be made separately from 10, but in any case, due to manufacturing reasons,
Any structure that is advantageous for use may be adopted.

The wedge ring 6 has a tapered inner surface that widens toward the back.
The outer surface is cylindrical, and its cross section has a wedge-shaped wall thickness that changes.

Both the taper surfaces of the collet 9 and the wedge ring 6 have the same inclination angle, and the needle roller bearing 7 inserted between the two taper surfaces is supported by the retainer 1' in an inclined state.

Therefore, when the wedge ring 6 is rotated, the needle roller bearing 7 rotates on its own axis and spirally revolves around the tapered surface of the collet 9, pushing the wedge ring 6 into the back of the collet 9 or pushing it toward the entrance side, creating a kind of screw action. do.

On the other hand, since the collet 9 is fixed at the center of the chuck, the collet 9 is tightened (contracted) or opened (restored) by the rotational movement and back-and-forth movement of the wedge ring 6.

The inclination angle of the needle roller bearing 7 is preferably set so that it is parallel to the line toward the center of the tapered surface, but the holding hole of the needle roller bearing 7 of the retainer 7' is set slightly larger than the needle roller bearing 7. When this is done, the needle roller bearing 7 automatically adjusts its attitude so that it can perform the spiral revolution movement.

When using the double structure chuck according to the present invention, a cutter is inserted into the holding hole 11, the wedge operating ring 4 is screwed, and the wedge ring 6 is rotated and pushed into the depths of the gripping sleeve 2.

The wedge ring 6 moves to the back of the holding hole 11 while rotating while being held between the two needle roller bearings 2 3 and 7.

At this time, the opposing surfaces of the needle roller bearings 3, 7 and the wedge ring 6 move relative to each other in a helical manner.

Therefore, the wedge ring 6 moves extremely smoothly without any frictional resistance.

As the wedge ring 6 moves to the back of the holding hole 11, the collet 9 is tightened toward the center and grips the cutter.

When the wedge operating ring 4 is rotated in the opposite direction, the wedge ring 6 is moved back and the collet 9 is released.

In the embodiment described above, the wedge ring 6 is rotated by operating the wedge operation ring 4, but the needle roller bearing 7 disposed diagonally around the outer circumference of the collet 9 rotates on its outer circumferential surface. As a result, the wedge ring itself generates a force that moves the collet 9 in the axial direction, and by utilizing this action, the diameter of the collet 9 can be contracted or restored by rotating the wedge ring 6 itself.

Therefore, in this case, the wedge operating ring 4 and related structures can be omitted.

In the present invention, a wedge ring 6 is disposed on the outer periphery of a collet 9 having a tapered outer surface, a gripping sleeve 2 fixed to the main body 1 is further disposed on the outer periphery, and a needle roller bearing is provided on the inner surface of the wedge ring 6. 7. It is also characterized in that roller bearings 3 are provided on the outer surface, so that the collet is held in a double manner.

Therefore, according to the present invention, the collet 9 only has to act to tighten the cutter and apply torque to it.
The force due to the moment that acts to move the gripping sleeve in the lateral direction is received by the bite sleeve 2, and lateral wobbling is prevented.

Therefore, since the collet 9 only needs to transmit torque, the wall thickness of the collet 9 can be made thin so that it can be easily contracted and restored by the rotation of the wedge ring 6 to grip or release the cutter. Moreover, the action of the above-mentioned clamping sleeve 2 prevents the collet 9 from wobbling laterally.

Even if significant cutting force is transmitted to the cutting tool by the action of such a double structure chuck, self-excited vibration does not occur in the collet 9, that is, the tool supported by it, and the cutting speed can be significantly increased. It can be done.

In addition, since the collet 9 is double-tightly held by the wedge ring 6 and the gripping sleeve 2, the chuck does not loosen during cutting, and durability is significantly improved.

Next, in order to clarify the effect of the present invention, a comparative example of the chuck having the structure shown in the above-mentioned publication and the chuck according to the present invention will be described.

Comparative Example 1 (Gripping Test) A double-structure chuck according to the present invention with a collet having an inner diameter of 32φ and a chuck having the structure described in Japanese Utility Model Publication No. 41-23987 were prepared, and these were held with a fixture. A 32φ round rod was inserted into the collet and tightened using a wrench.

A lever is provided perpendicularly to the round bar, and a weight is suspended from this lever so that torque is transmitted to the round bar.

A load was applied to the lever, the value was gradually increased, and the load immediately after slipping was read to measure the gripping force, that is, the gripping torque.

The chuck of the present invention supported a torque of 350 to 250 kg-m, whereas the conventional chuck supported a torque of 190 kg-m.
It could only hold a torque of m.

Comparative Example 2 (Cutting Test) The two types of chucks used in the comparative example were fixed to a milling machine, and an end mill was gripped to the chucks to cut carbon steel (S4
5C) The side surface of the block was rough-cut.

milling machine Hitachi Seiki■ 4■←■ (manufactured in 48) Rotation speed: 230rpm Cutting speed: 29m/min Depth of cut: 40mm End mill: NK top end mill Outer diameter of cutting blade: 40 mm Shank outer diameter: 32mm Total length: 150mm Cutting blade length = 65 Number of blades: 4 Under the above cutting conditions, the cutting width was set to 5, 10, and 15.

20. Change to 257+11E and set the feed speed (maximum feed speed) just before self-excited vibration occurs in the cutter (111111/
m1n) was measured.

In the chuck of the present invention, the feed speeds corresponding to the cutting widths are 700, 450, and 300, respectively.

250, 210 mm/min.

On the other hand, in the conventional chuck, the feed speed corresponding to the cutting width is 250°, 210°130°, and 90°, respectively.
, 50ii/min.

That is, it has been revealed that the chuck of the present invention can cut the same cutting width at a feed rate 2.8 to 4.2 times that of the conventional chuck.

Discussion on Comparative Examples The cutting test shown in Comparative Example-2 shows that the chuck of the present invention shows a particularly remarkable effect, and the chuck of the present invention has a cutting rate of 2.8 to 4.2 compared to the conventional chuck. It was found that the cutting speed was twice as high and the gripping force was strong, making it especially suitable for heavy cutting.

The main reason for this seems to be that the collet 9 is supported by the clamping sleeve 2, so there is no sideways wobbling of the collet.

On the other hand, with conventional collets, the neck (the base of the collet) must support the torque and moment generated by cutting, and in order to obtain gripping force (biting force), the collet must be thin-walled. This suggests that the underlying problem is that the neck is weak.

In addition, regarding the gripping force, in this invention, collet 9
is supported doubly by the wedge ring 6 and the gripping sleeve 2, which prevents the wedge ring from expanding and securely transmits tightening pressure to the collet 9, so the holding torque is higher than that of conventional chucks. 30% or more is high.

In the present invention, a collet 9 is provided extending coaxially with the taper shank 10, and a bite sleeve 2 is provided concentrically on the outer periphery of the collet 9 and extended from the taper shank 10. A wedge ring 6 is provided between the wedge ring 6, a needle bearing 7 is provided on the inner surface thereof, and a roller bearing 3 is provided on the outer surface of the wedge ring 6, so that the collet 9 can move forward and backward.
It is distinctive in that it is held twice.

Therefore, the pressing force to tighten the collet 9 when gripping the cutting tool is generated by the wedge ring 6, and the wedge ring 6
The expansion of is suppressed by the occlusal sleeve 2.

In other words, the collet 9 connects the wedge ring 6 and the gripping sleeve 2.
A strong gripping force is generated because the two are pressed doubly.

On the other hand, during cutting, a moment trying to bend the collet 9 and a force trying to restore it to its original state are generated, which tends to cause self-excited vibration in the cutting tool.

In the present invention, the wedge ring 6 is connected to the tapered shank 1.
It is held by a gripping sleeve 2 extending at 0, and the gripping sleeve 2 supports the moment around the root, so it can sufficiently withstand heavy cutting.

That is, in the present invention, the latching sleeve 2 suppresses the lateral wobbling of the collet 9 via the wedge ring 6, and takes full advantage of the advantage of the known technology that the tool can be easily attached and detached. This provides extremely excellent industrial benefits in that it completely eliminates the defects that tend to cause sideways movement.

The inner surface of the wedge ring 6 has a tapered surface that widens toward the tip, and this tapered surface is formed to correspond to the taper of the collet 9.

Further, the outer surface of the wedge ring 6 is formed into a cylindrical surface having the same diameter in its length direction, and the inner surface of the gripping sleeve 2 is similarly formed into a cylindrical surface having the same diameter in its length direction.

The needle roller bearing 7 is provided to be inclined with respect to the axis of the chuck, and rotates in a spiral manner (rotates and revolves) on the tapered surface 8 of the collet 9 as the wedge @ 6 rotates. It has the function of moving the chuck forward or backward in the axial direction.

In the embodiment, a needle roller bearing 3 is provided between the wedge ring 6 and the gripping sleeve 2, but this is because the outer diameter of the wedge ring 6 does not support the force that tends to expand. Other types of bearings may be used as long as they allow rotation.

That is, the initial force for tightening the cutting tool with the collet 9 is generated in the wedge ring 6, and at this stage, almost no internal pressure is generated in the gripping sleeve 2 due to the wedge ring 6.

Next, when the wedge ring 6 is rotated and a large clamping force is generated on the collet 9, the wedge ring 6 expands slightly and presses the inner surface of the gripping sleeve 2 via the roller bearing 3, causing the wedge ring 6 to Prevent expansion.

Therefore, the roller bearing 3 may not generate a force that moves the wedge ring 6 back and forth, and preferably a needle roller bearing is used, but a ball bearing or a ground type bearing may also be used. Yes, this point should be selected in consideration of issues such as the dimensions of the chuck, machining accuracy, or strength.

Furthermore, in the embodiment of the present invention, the tapered shank 10
Although the gripping sleeve 2 and the gripping sleeve 2 are integrally formed, these members may be separated from each other depending on material selection and manufacturing convenience.

[Brief explanation of drawings]

The figure is a front view of the right half of the chuck according to the embodiment of the present invention. 1... Body, 2... Biting sleeve, 3
... Needle roller bearing provided on the inner surface of the gripping sleeve, 4 ... Wedge operation ring, 5 ...
... Tapered surface of wedge ring, 6 ... Wedge ring, 7 ... Needle roller bearing link fitted to tapered surface 5 of wedge ring, 8 ... Collet Tapered surface of 9...collet.

Claims (1)

[Scope of utility model registration request] A taper shank 10, a collet 9 extending coaxially with the taper shank 10, and a collet 9 located concentrically on the outer periphery of the collet 9,
It consists of a gripping sleeve 2 extending from the tapered shank 10 and a wedge ring 6 inserted between the collet 9 and the gripping sleeve 2, and the outer surface of the collet 9 has a tapered surface, The inner surface of the wedge ring 6 is formed into a tapered surface corresponding to the outer surface of the collet 9, and the outer surface is formed into a cylindrical surface corresponding to the inner surface of the gripping sleeve 2. A needle roller bearing 7 is provided between the wedge ring 6 and the inner surface of the gripping sleeve 2, and a bearing 3 is provided between the outer surface of the wedge ring 6 and the inner surface of the gripping sleeve 2. When the wedge ring 6 is rotated, it moves back and forth by the spiral movement of the needle roller bearing 7 against the surface of the collet 9, so that the collet 9 is held by the wedge ring 6 and the gripping sleeve 2. A double chuck consisting of