JPH0627314Y2 - Tool head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention holds a tool such as a drill, an end mill, or a tap having a fluid passage formed inside, at the tip, and is supplied from a fluid supply source through the fluid passage. The present invention relates to a tool head adapted to eject a fluid toward a cutting edge side.

2. Description of the Related Art In machining with a machining center, a tool head equipped with various tools according to the machining conditions of a workpiece to be machined is attached to the spindle of the machining center by an automatic tool changer (ATC), and a predetermined machining process is performed with the same setup. Are being carried out one after another. In such machining, it is very important to dissipate the heat generated by cutting as quickly as possible, especially how quickly the heat generated by rough machining is dissipated before finishing machining. .

For this reason, the tool head for the machining center holds an oil hole type tool.

Here, the oil hole type tool refers to a tool such as a drill, an end mill, a tap, etc., in which a fluid passage such as cutting oil and air is formed. A form is adopted in which the work is cooled or cutting chips are removed.

FIG. 2 shows a conventional example of such a tool head. There, a casing 20 for rotatably supporting the tool drive shaft 10 fitted and connected to the main shaft 2 of the machining center is provided at the front end side, and a fluid passage 41 is formed inside at the front end side. It is configured to hold the drill 40. On the outer periphery of the casing 20, a support member 30 having a positioning pin 31 that engages with a fitting groove 33 of a positioning block 32 on the machining center side to prevent the casing 20 from rotating is connected.

Further, when the positioning pin 31 is engaged with the fitting groove 33, the fluid introduction passage 311 provided inside the positioning pin 31 is provided.
And a fluid supply source (not shown) provided on the side of the machining center.

The fluid supplied from the fluid supply source via the fluid introduction path 311 is a fluid passage 35 provided inside the support member 30,
An annular first fluid passage 21 provided on the inner circumference of the casing 20, a second fluid passage 13 provided inside the tool drive shaft 10, and a drill.
It is adapted to be jetted to the blade tip side of the drill 40 via a fluid passage 41 provided inside the 40. In the figure, 23 and 23 are ball bearings that rotatably support the tool drive shaft 10.

Also, the first fluid passage 21 in the casing 20 and the tool drive shaft
O-rings 22 and 22 are provided at the communicating portion of 10 with the second fluid passage 13 so that fluid does not leak from this portion.

However, in the case of the above-described conventional example, it is necessary to engrave O-ring mounting grooves 221 for inserting the O-rings 22 on both sides of the first fluid passage 21, so that the seal is formed. However, there is a drawback in that the axial length dimension required for the tool lengthening becomes long and, as a result, the tool head becomes long.

For this reason, there is a limit in increasing the rigidity of the tool head,
In particular, when the end mill and the tool head have a cutting form in which the end mill runs laterally with respect to the work, a large bending moment acts on the end mill and the tool head, resulting in a problem that the machining accuracy is significantly impaired.

Further, although the O-rings 22 and 22 can prevent the fluid from leaking to the outside, the ball bearings 23 and 23 do not have means for radiating friction heat generated between the ball bearings 23 and 23 and the tool drive shaft 10. There was also the drawback that it could impair the life of the 23.

The present invention has been made in view of the above circumstances, and can reduce the axial length dimension required for sealing as much as possible.
Another object of the present invention is to provide a tool head capable of suppressing heat generation of the bearing.

A tool head according to the present invention has a base end side connected to a main shaft of a machine tool, a tool drive shaft holding a tool having a fluid passage therein on the front end side, and the tool. In a tool head having a cylindrical casing that rotatably supports a drive shaft and ejecting a fluid supplied from a fluid supply source through the fluid passage to the cutting edge side, an inner surface of the casing is provided. An annular first fluid passage that is provided over the entire circumference and is supplied with fluid from the fluid supply source;
In order to supply the fluid supplied to the fluid passage to the fluid passage in the tool held by the tool drive shaft, a second fluid passage provided from the outer surface of the tool drive shaft toward the central portion, and the casing A pair of bearing accommodating portions, which are provided at the tip and the base end side of the first fluid passage on the inner surface, respectively, and whose end faces on the first fluid passage side are bearing seats, and the tool drive shaft are rotatable inside the casing. A pair of bearings fixed in the pair of bearing accommodating portions and an outer peripheral portion between the outer ring of the bearing and the bearing seat, and one surface of the inner peripheral portion of the inner ring of the bearing. A pair of annular and plate-shaped elastic seal members, the other surface of which is in contact with the first fluid passage, between the elastic seal member and the bearing due to the fluid pressure in the first fluid passage. Is characterized by self-sealing

Action When the fluid in the first fluid passage leaks from between the seal member and the bearing, the labyrinth effect causes the inner peripheral portion of the seal member to be pressed against the inner ring of the bearing by the pressure of the fluid, and the pressure of the fluid is insufficient. With no pressure, it will self-seal during this time.
Further, since the seal member is cooled by the fluid, the friction heat generated in the bearing is effectively dissipated through the seal member.

Embodiment Hereinafter, an embodiment of the tool head of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway front view showing a tool head according to the present invention.

The head 1 of the present invention comprises a tool drive shaft 10 whose base end is fitted and connected to a main shaft 2 of a machining center, a cylindrical casing 20 which rotatably supports the tip end of the tool drive shaft 10, and a casing 20. A support member 30 that is connected to the outer peripheral edge and prevents the casing 20 from rotating, and a casing of the tool drive shaft 10.
Ring part 12 fitted on the part displaced slightly from 20 to the base end side
And a tool holder portion 11 provided on the tip side of the tool drive shaft 10,
The tool holder 11 includes a drill 60 which is held at the tip of the tool holder 11 and which has a fluid passage 41 provided therein. The fluid is supplied from a fluid supply source (not shown) mounted on the machining center side. It has a basic structure in which it is jetted to the cutting edge side via.

The tool head 1 is mounted by grasping the V groove 211 provided in the middle portion of the ring portion 12 with the grip portion of the automatic tool changer, and in this state, the taper shank provided at the base end portion of the tool drive shaft 10.
This is done by pushing 14 into the fitting hole 3 of the spindle 2.

At the same time, the positioning pin 31 provided on the supporting member 30 is provided on the machining center side.
It is designed to engage the fitting groove 33 (or hole) of 32,
This will prevent the casing from rotating. The positioning pin 31 is always elastically biased toward the base end by a coil spring 34 mounted inside the support member 30.

Further, when the positioning pin 31 is engaged with the fitting groove 33, the fluid introduction passage 31 provided inside the positioning pin 31 is provided.
1 and the fluid supply source are communicated with each other, and the fluid supplied from the fluid supply source through the fluid introduction passage 311 is the fluid passage 35 provided inside the support member 30 and the inside of the casing 20. Circular annular first fluid passage 21, tool drive shaft
It is adapted to be jetted to the cutting edge side of the drill 40 via the second fluid passage 13 provided inside the drill 10 and the fluid passage 41 provided inside the drill 40.

Next, details of the casing 20 will be described. casing
Bearing housing portions 230, 230 for housing ball bearings 23, 23 for rotatably supporting the tool drive shaft 10 are provided on the inner surface of the distal end portion and the inner surface of the proximal end portion of 20, respectively, with the first fluid passage 21 interposed therebetween. ing. The bearing accommodating portion 230 has a larger inner diameter than the first fluid passage 21, and the end surface on the first fluid passage 21 side has a bearing seat 23.
It is 1. The ball bearings 23, 23 in the bearing accommodating portions 230, 230 are inserted into the bearing accommodating portions 230, 230 from the front side and the base end side, respectively, and are prevented from coming off from the front side and the base end side. An outer peripheral portion of a plate-shaped ring-shaped seal member 24 is sandwiched between the outer ring of the ball bearing 23 and the bearing seat 231. The inner peripheral portion of the seal member 24 has one surface in contact with the inner ring of the ball bearing 23 and the other surface in contact with the first fluid passage 21. The seal member 24 is made of an elastic material, and is made of a material such as tetrafluoroethylene in consideration of strength, heat generation and the like. In addition, 25 is a ball bearing 23, 23
Is a packing arranged outside the seal, and seals this portion to prevent fluid or dust scattered from the cutting edge side from entering.

Thus, when the fluid is supplied into the tool head 1, the fluid pressure causes the seal members 24, 24 to move to the ball bearings 23, 23.
It will be in close contact with the side surface of the and will prevent the fluid from leaking to the outside from this part. In addition, a seal member lubricated with fluid
24 will function to radiate the frictional heat generated between the ball bearing 23 and the tool drive shaft 10.

Further, the case where the present invention is applied to the tool head 1 holding the drill 40 in the tool holder part 1 has been described, but a tool head having a so-called milling chuck for holding a tool in a cylinder body having many needle rollers is described. Of course, it is also applicable.

Further, in the above embodiment, the positioning pin 31 is used to supply the fluid, but the fluid supply source and the first fluid passage 21
It is also possible to adopt a mode in which the and are connected by a hose or the like to supply the fluid.

Further, it goes without saying that the tool head 1 may be connected not to the machining center but to the spindle of a machine tool such as a drilling machine or a milling machine.

Effects of the Invention With the above tool head of the present invention, the size required for sealing can be shortened as compared with the case of the conventional example, and as a result, the length of the tool head can be shortened accordingly. Therefore, since the rigidity of the tool head can be remarkably improved, the processing accuracy can be improved. This is especially effective when the end mill is configured to run laterally. In addition, since the seal member seals between the first fluid passage and the bearing at a pressure that is sufficient for the fluid pressure, the rotation of the inner ring of the bearing is not unnecessarily hindered. . Further, since the seal member radiates the frictional heat generated in the bearing, there is an effect that the life of the bearing is not impaired.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an embodiment of a tool head according to the present invention, and FIG. 2 is a partially cutaway front view of a conventional tool head. 10 ... Tool drive shaft 13 ... Second fluid passage 20 ... Casing 21 ... First fluid passage 23 ... Ball bearing 24 ... Seal member 40 ... Drill 41 ... Fluid passage

Claims (1)

[Scope of utility model registration request] 1. A base end side is connected to a spindle of a machine tool,
A tool drive shaft holding a tool having a fluid passage therein on the tip side, and a cylindrical casing rotatably supporting the tool drive shaft, and a fluid supplied from a fluid supply source through the fluid passage. In a tool head adapted to eject a blade toward a cutting edge, an annular first fluid passage, which is provided on the inner surface of the casing over the entire circumference and is supplied with fluid from the fluid supply source, and the first fluid passage. A second fluid passage provided from the outer surface of the tool drive shaft toward the central portion in order to supply the fluid supplied to the fluid passage in the tool held by the tool drive shaft and the inner surface of the casing. The first fluid passage is provided at the tip and the base end side,
A pair of bearing accommodating portions whose end faces on the first fluid passage side are bearing seats, and a pair of bearings fixed in the pair of bearing accommodating portions so as to rotatably support the tool drive shaft inside the casing. An outer peripheral portion is held between the outer ring of the bearing and the bearing seat, one surface of the inner peripheral portion is in contact with the inner ring of the bearing, and the other surface is in contact with the first fluid passage. And a pair of elastic seal members,
A tool head, wherein the elastic seal member and the bearing are self-sealed by the pressure of the fluid in the fluid passage.