JPH0533245Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a tool head for attaching tools such as drills and end mills to the main spindle of machine tools such as machining centers, drilling machines, and milling machines. This product relates to a tool head with a built-in mechanism that enables high-speed machining.

Prior Art A conventional example of this type of tool head is shown in FIG. There, an internal gear 138 is provided on the inner circumferential surface of a housing 130 that rotatably supports the tip of a tool head body 120 whose base end shaft portion is fitted and connected to the main shaft 101 of a machining center, and The gear 138 provided on the tool drive shaft 160 built into the tool head body 1
The internal gear 138 and the planetary gear 126 that mesh with the gear 136 constitute a speed increasing mechanism consisting of a planetary gear train.
The structure is such that a tool 161 connected to the tip of the tool 161 is rotated at high speed.

Therefore, in such a tool head, it is necessary to cool down the tool 161, which becomes hot when cutting a workpiece (not shown). This cooling is performed by a positioning block 300 connected to a cooling source (not shown), a support member 150, and a nozzle 15 connected to the tip side of the support member 150.
This is done by spouting a cooling fluid such as cutting oil to the cutting edge side of the tool 161 through the pipe 2 .

Note that the support member 150 is attached to the housing 130.
This is to prevent rotation of the tool head main body 120, and this rotation prevention is performed by supporting member 15.
This is done by pushing the positioning pin 150 provided on the tip side of the positioning block 1 into the support groove 301 provided on the positioning block 300.

Problems to be Solved by the Invention By the way, in the case of the above-mentioned tool head, it is necessary to cool not only the tool 161 but also the tool head. That is, the rotating tool drive shaft 160, the tool head body 120, and the pinion 12
The inside of the tool head, which is in a closed room, becomes hot due to the heat generated between the tool head and the bearings such as ball bearings that support them, so if the tool head is not cooled, it may cause seizure of the bearing. , this impairs the service life and causes wear and tear on the tool drive shaft 160 and the like. Furthermore, the tool head body 120 and the tool drive shaft 160 extend toward the cutting edge of the tool 161, increasing the depth of cut, which impairs machining accuracy. Furthermore, maintenance work will be required frequently.

However, since the conventional example described above did not have a means for cooling the tool head, it was not possible to eliminate this drawback.

The present invention was developed in view of the above circumstances, and it not only cools the tool, but also cools the inside of the tool head to prevent seizure of the bearing, thereby extending the life of the bearing. The present invention aims to provide a tool head that can prevent wear and tear on the tool drive shaft, improve machining accuracy, and reduce the frequency of maintenance work.

Means for Solving the Problems The tool head according to the present invention has a proximal end connected to the main shaft of a machine tool, and a tool drive shaft for holding a tool is supported in the distal end via a bearing. a head body, a gear provided at the base end of a tool drive shaft supported by the tool head body, and fixedly arranged to surround the tool drive shaft;
A housing having an internal gear facing the gear at the base end, and a housing having a distal end externally fitted onto the distal end of the tool head body via a bearing, and a tool head configured to mesh with the gear and the internal gear. an outer circumference of a bearing interposed between the tool drive shaft and the tip of the tool head body on the outer circumferential side of the tool drive shaft; A bearing interposed between the tip of the tool head main body and the housing tip on the outer circumference side is positioned on the side, and a shaft is placed in the housing on the outer circumference side of the bearing so as to surround the bearing on the inner circumference side. An annular fluid passage is provided extending in the center direction, cooling fluid is supplied to the fluid passage from its base end, and the tip of the fluid passage is opened toward the cutting edge of the tool held by the tool drive shaft. There is.

Operation By supplying the cooling fluid to the fluid passage, the cooling fluid is ejected from the tip of the fluid passage to the cutting edge of the tool held by the tool drive shaft. At the same time, heat generated on the inner peripheral side of the fluid passage is dissipated via the cooling fluid flowing through the fluid passage. Thus, a bearing interposed between the housing and the tool head body and a bearing interposed between the tool head body and the tool drive shaft are located in this order on the inner peripheral side of the fluid passage. Since the rotation of the tool head body is accelerated and transmitted to the tool drive shaft, the inner bearing rotates at a higher speed than the outer bearing and generates more heat. Then, the cooling fluid flows around the outer circumferential side of the outer bearing, which generates less heat. As a result, a temperature gradient is formed in this portion where the temperature gradually decreases from the inner circumferential side to the outer circumferential side. As a result, both the inner and outer bearings are efficiently cooled by the cooling fluid.

Embodiment Hereinafter, one embodiment of the tool head according to the present invention will be described based on the drawings. FIG. 1 is a cross-sectional view showing the tool head attached to the main shaft of a machining center.

This tool head 10 includes a tool head main body 20 provided on the proximal end side corresponding to the left side in the figure, a housing 30 connected to the distal end side of the tool head main body 20, and a housing 30 connected to the distal end side of the tool head main body 20.
A support member 50 provided on the outer peripheral surface of the support member 50 is provided.

In the figure, reference numeral 1 indicates the main shaft of an achining center to which a tool head 10 is attached. This attachment is performed by fitting the taper shank 20a provided at the proximal end of the tool head body 20 into the taper hole 2 of the main spindle 1.

At this time, the positioning pin 51 of the support member 50 is simultaneously inserted into the pin groove (or hole) 4 of the positioning block 3.
This ensures that the housing 30 is prevented from rotating. That is, the tool 44 held at the tip of the tool head 10 is now positioned with respect to the workpiece (not shown).

A first fluid passage 5 with a fluid outlet 4a located in the pin groove (or hole) 4 is provided inside the positioning block 3, and the first fluid passage 5 is supplied with, for example, cutting oil from the machining center side. , air, or a cooling fluid such as oil mist air. Further, a second fluid passage 52 is provided inside the support member 50, and a fluid inlet 51a is located at the tip of the positioning pin 51. When the positioning pin 51 is connected to the positioning block 3,
The first and second fluid passages 5 and 52 are in communication with each other.

As shown in the figure, the tip 21 of the tool head body 20 is formed into a cylindrical shape.
A housing 30 is fitted onto the outside. Specifically, two ball bearings 32a,
32b are inserted in this order and locked with the snap spring 35, so that the tip portion 21, that is, the tool head main body 20, is rotatably supported.

Inside the tip 21, a tool drive shaft 40 holding a tool 44 at the tip is connected to a ball bearing 22a,
It is rotatably supported by 22b and 22c. Ball bearing 2 located at the most proximal end of the tip portion 21
Planetary gears 26 are attached using pins 27 at three locations in the circumferential direction corresponding to positions slightly deviated toward the base end side from 2a (only one planetary gear 26 is shown in the drawing). This installation requires the tip 21
A pin mounting hole 29a that is long in the axial direction is opened from the outer circumferential surface side toward the axial center by, for example, milling or electrical discharge machining, and a planetary gear insertion hole 29b is opened orthogonally to this pin mounting hole 29a. This is done by inserting a pin 27 through the axial center of the planetary gear 26 and inserting this pin 27 into the pin mounting hole 29a. The planetary gear 26 has ball bearings 28a, 2 fitted on the corresponding outer peripheral surface of the pin 27.
It is rotatably supported by 8b.

An internal gear 36 that meshes with the planetary gear 26 is formed on the inner circumferential surface of the housing 30 corresponding to the planetary gear 26, and the planetary gear 2 of the tool drive shaft 40
A gear 41 that meshes with the planetary gear 26 is provided on the outer peripheral surface facing the planetary gear 26 .

Thus, when the main shaft 1 is rotated, the planetary gear 26 rolls on the internal gear 36 in the opposite direction to the rotational direction of the main shaft 1, while rotating the gear 41 in the same direction as the main shaft 1, and the teeth of each of these gears rotate. The tool drive shaft 40 and the tool 44 rotate at increased speeds relative to the main shaft 1 at a predetermined speed increase ratio corresponding to the numerical ratio.

A fluid communication tube 53 is provided at the distal end of the support member 50, and the fluid communication tube 53 has a proximal end communicating with a second fluid passage 52 provided inside the support member 50.
3 is in communication with an annular third fluid passage 37 provided in the housing 30. This communication is
This is done by connecting the tip of the fluid flow pipe 53 to a round hole 37a connected to the inlet side of the third fluid passage 37.

Here, the third fluid passage 37 is a cylindrical cover tube 30 formed by reducing the diameter at the tip side of the small diameter part of the stepped cylindrical housing main body 30a whose tip side has a small diameter.
b are concentrically loosely connected. That is, the gap formed between the inner circumferential surface of the cover tube 30b and the outer circumferential surface of the small diameter portion serves as the third fluid passage 37. The outlet side located at the tip side of the third fluid passage 37 is bent inward, and is supplied to this through the first and second fluid passages 5, 52, the fluid communication pipe 53, and the round hole 37a. The cooling fluid is ejected toward the cutting edge side of the tool 44. In addition,
The small-diameter portion and the cover tube 37 are connected to each other by a plurality of fastening members 30c (only one shown in the drawing) such as fluoroset screws fastened in the circumferential direction thereof.

Thus, when the cooling fluid is ejected, the tool 44
At the same time, the housing 30 and the members provided inside the housing 30 are also cooled. Therefore, when driving the tool drive shaft 40, each ball bearing 32a, 32b, 2
Since the heat generated in 8a, 28b, 22a, 22b, and 22c is dissipated without being accumulated, the ball bearings do not seize.

Other Embodiments FIG. 2 shows another embodiment of the invention. In this embodiment, the present invention is applied to an angle head.

The angle head herein refers to a tool head in which the tool drive shaft 40 is inclined at a predetermined angle (90° in the illustrated example) with respect to the tool head body 20, and is suitable for machining workpieces having an inclined machining surface. ing.

That is, the transmission shaft 6 connected to the tool head body 20
0 rotation is transferred to the transmission shaft 60 via bevel gears 61 and 62.
The power is transmitted to the tool drive shaft 40 which is inclined at 90 degrees to the tool drive shaft 40, and the tool drive shaft 4 is
0 and the tool 44 held therein are rotated at high speed.

A third fluid passage 37 similar to that described above is formed in the housing 30 that further rotatably supports the inner cylinder 63 that rotatably supports the tool drive shaft 40. It is starting to be ejected.

The entire details of the illustrated embodiment are as described above,
The present invention can be modified in various ways. That is, an embodiment may be adopted in which the third fluid passage 37 and the fluid supply source are connected via a hose or the like to cool the tool 44 and the housing 30, and in addition to this cooling mode, for example, the main shaft 1 An embodiment may be adopted in which the inside of the tool head and the tool 44 are cooled by a fluid passage that communicates the inside of the tool head with the inside of the tool drive shaft 40, etc. In this case, the tool used is a so-called oil hole, which has a hole formed therein to allow fluid to flow therethrough.

Effects of the invention According to the invention as described above, there is no problem in cooling the tool, and the inside of the tool head can be cooled, which could not be done in the conventional example described above, so it is possible to prevent seizure of the bearing. Become. Therefore, the life of the bearing can be extended, and wear and tear on the tool drive shaft and the like can be prevented. Furthermore, since there is no risk that the tool head and tool drive shaft will extend toward the cutting edge of the tool, the depth of cut can be maintained uniformly, and machining accuracy can be improved. Furthermore, there are also advantages in that the frequency of maintenance work can be reduced and continuous operation over a long period of time is possible.

In particular, the bearing interposed between the tool head body tip and the housing tip on the outer circumference side is positioned on the outer circumference side of the bearing interposed between the tool drive shaft and the tool head body tip on the outer circumference side. , an annular fluid passage is provided in the housing on the outer circumferential side of the bearing, extending in the axial direction so as to surround the inner circumferential side of the housing, so that the fluid passage is provided in this part from the inner circumferential side to the outer circumferential side. A temperature gradient is formed that gradually lowers the temperature, and an excellent cooling effect is obtained in which both the inner and outer bearings are efficiently cooled by the cooling fluid. In addition, since the fluid passage for the cooling fluid used to cool the cutting edge of the tool is also used as a cooling jacket to cool the inside of the tool head, it is possible to cool the cutting edge of the tool and the inside of the tool head at the same time. Regardless, head structure complexity is avoided and cooling fluid volume and cost are saved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a tool head according to the present invention attached to the main shaft of a machining center, and FIG. 2 is a cross-sectional view showing another embodiment of the present invention. FIG. 3 is a single sectional view similarly showing the conventional example. 1... Spindle, 20... Tool head body, 26...
... Planetary gear, 30 ... Housing, 36 ... Internal gear, 37 ... Third fluid passage, 40 ... Tool drive shaft, 41 ... Gear, 44 ... Tool.

Claims (1)

[Scope of utility model registration request] A tool head body whose base end is connected to the main shaft of a machine tool, and a tool drive shaft that holds a tool is supported within the tip part through a bearing, and the tool drive shaft supported by the tool head body. It is fixedly installed so as to surround the gear provided at the base end and the tool drive shaft, and has an internal gear facing the gear at the base end, and the distal end is connected to the distal end of the tool head body. and a planetary gear supported on the tool head body so as to mesh with the gear and the internal gear, the planetary gear forming a speed increasing mechanism with the gear and the internal gear. A bearing interposed between the tool head main body distal end and the housing distal end on the outer circumferential side thereof is provided on the outer circumferential side of the bearing interposed between the tool drive shaft and the tool head main body distal end on the outer circumferential side thereof. An annular fluid passage is provided in the housing on the outer circumferential side of the bearing and extends in the axial direction so as to surround the inner circumferential bearing. A tool head that supplies fluid and has a fluid passage whose tip is opened toward the cutting edge of a tool held by a tool drive shaft.