JP4353597B2 - Long nose tool holder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a long nose type tool holder, and more particularly to a long nose type tool holder used for small-diameter end mill drilling.
[0002]
[Prior art]
As a tool holder suitable for deep engraving with a small-diameter end mill and drill, a small-diameter tool holder (collet) is attached to the holder body that has a shank that is attached to the spindle of the machine tool, and the end mill and drill are attached to the tool holder A slim and long type tool holder to which a tool (blade) such as the above is mounted is known.
[0003]
[Problems to be solved by the invention]
The slim and long type tool holder as described above can perform deep end mill drilling as compared with a normal tool holder for end mill drilling, but when the axial length of the tool holder becomes long, Insufficient rigidity of the tool holder occurs, cutting with high rigidity cannot be performed, and the axial length is limited to about 200 mm, and deep engraving is limited.
[0004]
For this reason, machining of narrow deep grooves such as molds that require high accuracy has been conventionally performed by electrical discharge machining, not depending on end mills and drilling, which reduces the productivity of die machining. It has become.
[0005]
Also, in machine tools that process free-form surfaces of large dies, there is a limit to speeding up the spindle speed from the limit peripheral speed of the spindle bearing, and in the case where the tool holder is driven to rotate by the spindle of the machine tool, Since the rotation speed is determined by the spindle rotation speed, the tool cannot be rotated at high speed, and high-efficiency, high-performance cutting cannot be performed.
[0006]
The present invention has been made paying attention to the above-mentioned problems, and can perform cutting with a small diameter tool deeper than a conventionally known slim / long type tool holder with high rigidity and high accuracy. Another object of the present invention is to provide a long nose type tool holder capable of performing cutting with a small diameter tool with high efficiency and high performance by high-speed rotation.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a holder body having a main shaft or ram of a machine tool, a mounting portion for the head of the machine tool, a long nose portion having a hollow shape, a motor built in the holder main body, and a drive connection with the motor. A tool rotation shaft extending in the axial direction in the long nose portion, an aerostatic bearing mounted on the long nose portion to rotatably support the tool rotation shaft, and a tip end portion of the tool rotation shaft. A tool holder for fixing and holding the tool, and the tool rotation shaft includes a straight shaft portion and a taper shaft portion, and the straight shaft portion is rotatably supported by the long nose portion by an aerostatic bearing. A long nose configured such that a tool is attached to the tapered tip of the tapered shaft portion protruding from the long nose portion by the tool holder. A tool holder.
[0008]
According to a second aspect of the present invention, in the long nose tool holder according to the first aspect, the tool holder has a cylindrical shape by including a tool holding hole having a substantially triangular cross-sectional shape. By pressing each apex portion of the tool holding hole from the outside to the inside of the tool holding body, the tool holding body is elastically deformed to make the cross-sectional shape of the tool holding hole substantially circular, and this state The tool holder is configured to insert the tool into the tool holding hole, release the pressing after the insertion, and to fix and hold the tool by the restoring force by the release.
[0009]
The invention according to claim 3 is the long nose tool holder according to claim 1 or 2, wherein the motor is built in the mounting portion, and the long nose portion protrudes from the mounting portion, The rotor shaft of the motor and the tool rotation shaft are a long nose tool holder that is drivingly connected by a coupling member.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show an embodiment of a long nose tool holder according to the present invention.
[0013]
This long nose type tool holder has a holder main body 100 which is an assembly of a main body housing 10 and a long nose member 20. The main body housing 10 has a taper shank portion 11 as an attachment portion for the spindle 200 of the machine tool, and incorporates a high-frequency motor 12 that rotates at high speed by high-frequency excitation.
[0014]
The long nose member 20 is fixed to the main body housing 10 and has a small-diameter sleeve shape having a hollow portion 21 formed through the center thereof. In the hollow portion 21 of the long nose member 20, a tool rotating shaft 30 made of a solid shaft material having a sufficiently smaller diameter than the main shaft 200 is disposed.
[0015]
The tool rotation shaft 30 is disposed on the long nose member 20 and is provided on the straight shaft portion 31 rotatably supported by the radial aerostatic bearings 22 and 23 disposed on the long nose member 20. A thrust surface portion 32 that is rotatably supported by the thrust air hydrostatic bearing 24, a tapered shaft portion 33 provided on the distal end side of the straight shaft portion 31, and an extremely small diameter straight provided on the distal end of the tapered shaft portion 33. The shaft part 34 is comprised.
[0016]
The tool rotating shaft 30 is drivingly connected to the rotor shaft 14 of the high-frequency motor 12 by the coupling member 13 at the base end side, and is directly driven by the high-frequency motor 12.
[0017]
The proximal end side of the cylindrical tool holder 35 is fixedly mounted in a concentric state by shrink fitting or the like on the extremely small straight shaft portion 34 at the tip of the tool rotating shaft 30. The tool holder 35 has a shank portion 41 of a small-diameter tool 40 such as an end mill or drill having a small diameter of about 2 to 5 mm inserted into the cylinder from the tip side, and the small-diameter tool 40 is fixedly held concentrically by shrink fitting. is doing.
[0018]
In the long nose tool holder having the above-described configuration, the straight shaft portion 31 and the thrust surface portion 32 of the tool rotating shaft 30 are rotatably supported by the long nose member 20 by the radial air static pressure bearings 22 and 23 and the thrust air static pressure bearing 24. Since the small-diameter tool 30 can be attached to the very small-diameter straight shaft portion 34 at the tip of the tapered shaft portion 33 protruding from the long nose member 20, the tool rotating shaft 22 is driven to rotate at high speed by the high-frequency motor 12 without hindering the bearing portion. The small-diameter tool 30 can cut the deep groove portion and the like with high rigidity and accuracy.
[0019]
Since aerostatic bearings do not have mechanical contact parts, they generate less heat and can rotate 3-5 times faster than when a rotating shaft of the same diameter is supported by a rolling bearing. Since the amount of shaft runout can be reduced to 1/10 or less compared with the case of using a general precision bearing for machine tools, the necessary shaft runout accuracy can be ensured even if the shaft length of the tool rotating shaft 30 is extended. Can do.
[0020]
Further, the tool holder 35 is fixed to the tip of the tapered portion of the tool rotation shaft 30 by shrink fitting, and holds the small-diameter tool 40 by shrink fitting, so that the tool holder 35 is external to the tip side of the tool rotation shaft 30. The diameter is not greatly enlarged, and this also enables cutting with the small-diameter tool 30 in a deep portion.
[0021]
Further, since the small diameter tool 40 is rotationally driven by the high frequency motor 12 different from the main spindle motor of the machine tool, cutting with the small diameter tool 40 is highly efficient and high performance by high speed rotation that is impossible with the main spindle drive of the machine tool. Can be done.
[0022]
As described above, parts that have been machined by electrical discharge machining can be cut efficiently and with high accuracy, thereby shortening the machining time of the die and the like and reducing the machining cost. be able to.
[0023]
The small-diameter tool 40 can be attached by an elastically deformable tool holder 36 as shown in FIGS. 3A to 3C, in addition to the shrink-fit type fixing by the tool holder 35. . As shown in FIG. 3A, the tool holder 36 has a tool holding hole 37 having a substantially triangular cross-sectional shape in a free state, and each apex portion of the tool holding hole 37 from the outside. By pressing, the tool holder 36 is elastically deformed so that the tool holding hole 37 has a substantially circular cross-sectional shape as shown in FIG. 3B. In this state, the tool holding hole (cylinder) Inner) 37, the small diameter tool 40 is inserted, and thereafter the pressing force is released. As a result, the elastic deformation of the tool holder 36 is released and the tool holder 36 tries to return to its original shape, and the small diameter tool 40 is fixedly held by the restoring force due to the elastic deformation.
[0024]
In the above-described embodiment, the long nose tool holder is structured to be attached to the main shaft 200. However, as shown in FIG. 4, the long nose tool holder has a structure of the main body housing 10 of the holder main body 100. By modification, it can be attached to the ram 210 of the machine tool or the spindle head.
[0025]
In the above, the present invention has been described in detail with respect to specific embodiments. However, the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. This will be apparent to those skilled in the art.
【The invention's effect】
As understood from the above description, according to the long nose type tool holder according to the present invention, the tool rotation shaft having a smaller diameter than the main shaft is supported by the aerostatic bearing, and the tool rotation shaft is rotated by a built-in motor different from the main shaft motor. Since it is driven, high-speed cutting that is impossible with a spindle motor becomes possible. In addition, even if the tool rotation axis is a slender shaft, it is supported rotatably by a long nose member by an aerostatic bearing, so high support rigidity is obtained, and cutting with a small diameter tool in a deep part is highly rigid and accurate. Will be able to do.
[0026]
Further, according to the long nose type tool holder according to the present invention, the tool holder holds the tool by shrink fitting, so that the tool holder does not greatly increase the outer diameter on the tip side of the tool rotation shaft, Cutting with a small diameter tool in a deep part becomes possible.
[0027]
Further, according to the long nose type tool holder according to the present invention, the tool holder holds and holds the tool by the restoring force due to elastic deformation, so that the tool holder greatly enlarges the outer diameter on the tip side of the tool rotation shaft. This makes it possible to cut with a small diameter tool in a narrow and deep part.
[0028]
Further, according to the long nose type tool holder of the present invention, the tool is rotationally driven by the high-frequency motor built in the holder main body, so that cutting with a small diameter tool can be performed with high efficiency and high performance by high speed rotation.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a long nose tool holder according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a tip portion of a long nose type tool holder according to the present invention.
FIGS. 3A to 3C are enlarged sectional views showing a tool holding step of an elastically deformable tool holder of a long nose tool holder according to the present invention.
FIG. 4 is a cross-sectional view showing another embodiment of a long nose type tool holder according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Main body housing 11 Tapered shank part 12 High frequency motor 20 Long nose member 22, 23 Radial air static pressure bearing 24 Thrust air static pressure bearing 30 Tool rotating shaft 31 Straight shaft part 33 Tapered shaft part 40 Small diameter tool 100 Main body holder 200 Main axis 210 Ram

Claims (3)

A holder body having a spindle or ram of the machine tool, a mounting portion for the spindle head, and a hollow long nose portion;
A motor built in the holder body;
A tool rotation shaft that is drivingly connected to the motor and extends in the axial direction in the long nose portion;
An aerostatic bearing that is mounted on the long nose portion and rotatably supports the tool rotation shaft;
A tool holder attached to the tip of the tool rotation shaft and fixedly holding the tool;
Have
The tool rotation shaft includes a straight shaft portion and a taper shaft portion, the straight shaft portion is rotatably supported by the long nose portion by an aerostatic bearing, and the taper shaft portion protruding from the long nose portion. A long nose type tool holder , wherein a tool is attached to the tapered tip of the tool by the tool holder. In the long nose type tool holder according to claim 1,
The tool holder has a cylindrical shape by including a tool holding hole having a substantially triangular cross-sectional shape, and each apex portion of the tool holding hole is directed from the outside to the inside of the tool holder. By pressing, the tool holder is elastically deformed to make the cross-sectional shape of the tool holding hole substantially circular, and in this state, the tool is inserted into the tool holding hole, and after the insertion, the pressing is released, A long nose type tool holder , wherein the tool holder is configured to fix and hold the tool by a restoring force upon release . In the long nose type tool holder according to claim 1 or claim 2,
The motor is built in the mounting portion, the long nose portion protrudes from the mounting portion, and the rotor shaft of the motor and the tool rotation shaft are drivingly connected by a coupling member. Long nose tool holder.

Images