JP2014073561A - Side through holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten cooling effect of a blade tool by supplying a high-pressure coolant to a contact portion between the blade tool and a workpiece, and to achieve fine parting of chips.SOLUTION: In a side-through holder having a seal structure capable of recovering a leakage coolant when the coolant is supplied at high pressure by providing a drain passage 21 in a housing 3, cooling of a blade edge surface of a blade tool and chips, and parting and discharge of the chips are performed by high-pressure coolant supply, and as the result, feed speed of a drill can be heightened, to thereby enable highly efficient cutting.

Description

The present invention is a technique for supplying coolant to a cutting tool that is attached to a machine tool such as an NC lathe or a machining center via a holder, with respect to the cutting tool on the front end side of the holder body through a housing that is rotatably mounted on the holder body. The present invention relates to a seal structure for a side-through holder that can supply coolant at a high pressure.

  In a machine tool such as an NC lathe or a machining center, coolant is supplied from the tip of a cutting tool and processed to cool the cutting edge surface and chips and discharge chips. The coolant supply method includes a center-through method that is performed from the machine tool side through a flow path provided along the center axis of the holder that holds the cutting tool, and a housing that is attached to the holder on the outer peripheral surface of the intermediate portion so as to be relatively rotatable. There is a side-through method in which a coolant is supplied from a housing on the fixed side to a holder and a cutting tool on the rotating side. The present invention relates to a side-through system.

  As a conventional side-through type holder, a technique disclosed in Patent Document 1 is known. The side-through holder described in Patent Document 1 employs a plurality of seal structures to cope with high pressure. In the plurality of seal structures, a total of 4 to 6 seal rings are arranged three or two symmetrically across a coolant flow path extending radially from the outer peripheral side surface of the holder body. Among them, the seal ring on the housing side is fixed, and one of the seal rings on the holder body side rotates together with the holder body, and the other rotates relative to the holder body. .

JP 2000-308946 A

Therefore, in the seal structure shown in Patent Document 1, as the coolant supply pressure increases, one side of the seal ring rubs between the holder body and the front and rear holding rings, and wears early. There was a problem that the life of the seal ring was short.
In addition, the higher the coolant supply pressure, the more coolant leaked from these seals, and the high pressure decreased and could not be maintained. If the supply pressure of the coolant is low, the momentum of the coolant ejected from the cutting edge of a drill or the like is weak, the cooling of the cutting edge and the work material is insufficient, and there is a problem that the cutting speed cannot be increased.
In addition, when the coolant supply pressure is low, the force to sever the chips is weakened, and the cutting edges become hot due to frictional heat, leading to a reduction in the cutting edge life. There was also a problem that machine stoppage increased and automation was not possible.

The present invention is obtained by improving and removing the above in view of the above-described problems, and by providing a drain passage in the housing, a seal structure capable of recovering coolant that leaks when coolant is supplied at a high pressure. By supplying high-pressure coolant, the cutting edge surface of the cutting tool and the chips are cooled, and the chips are divided and discharged.As a result, the frictional heat of the cutting edge can be reduced and the feed rate of the drill can be increased. We are going to provide a side-through holder that can cut well.

The means of claim 1 adopted by the present invention in order to solve the above-mentioned problems is a holder main body in which a cutting tool can be attached to the front end portion, and a mounting portion to a machine tool such as a lathe is provided at the rear end portion; A housing mounted on the holder body through a bearing so as to be relatively rotatable, the housing having a radial flow path communicating with a coolant supply nozzle, and an annular port provided on the inner peripheral surface side; The holder main body has a radial flow path communicating with the annular port and an axial flow path continuously communicating with the attachment portion of the cutting tool, and the annular port is sandwiched between the holder main body and the housing. The side through holder is characterized in that the seal member is disposed at the side, packing members are disposed on both sides of the seal member, and a drain passage is provided in the housing between the both sides of the seal member and the packing member. .

The means of claim 2 adopted by the present invention to solve the above-mentioned problems is the side-through holder according to claim 1, wherein the seal member is a seal ring.

The means of claim 3 adopted by the present invention to solve the above-mentioned problems is the side-through holder according to claim 1, wherein the seal member is a labyrinth seal.

The means of claim 4 employed by the present invention to solve the above-mentioned problem is that the coolant is supplied at a high pressure of 7 MPa or more and 30 MPa or less, and the side through holder according to any one of claims 1 to 3. It is.

In the first aspect of the invention, the coolant is supplied at a high pressure, and a part of the coolant leaking from between the housing and the holder main body due to the high pressure is actively provided and recovered. I have to.
As a result, a high pressure is guaranteed, and the surroundings of the machine tool are not contaminated with coolant. By making the supply pressure of the coolant high, the cooling effect between the cutting tool and the work material is excellent, and it is possible to suppress the wear of the cutting tool and extend its life. As a result, the processing speed can be increased, and excellent and efficient hole processing is possible. In addition, the high-pressure coolant has an effect that the scraped chips are easily divided into short dimensions.

In the invention of claim 2, the seal member is a seal ring. In the invention of claim 3, the seal member is a labyrinth seal. In the case of the seal ring, since the outer peripheral surface of the seal ring and the inner peripheral surface of the housing are in contact with each other, the wear of the seal ring becomes severe when the rotation speed of the holder body exceeds about 3,000 rpm. Therefore, it is effective for low-speed rotating machine tools.
In the case of the labyrinth seal, since there is no contact portion between the rotating portion and the fixed portion, it is possible to cope with even a high speed rotation of 3,000 rpm or more.

  In the invention of claim 4, in any one of the inventions of claims 1 to 3, the coolant is ejected at a high pressure of 7 MPa or more and 30 MPa or less. As a result, the chips cut off from the work material are immediately divided at an extremely short size stage, flow into the discharge groove of the blade tool together with the coolant, and are smoothly discharged from the discharge groove to the outside of the blade tool. Further, the chips discharged from the cutting tool are in the shape of a short strip, can be accommodated in a container of an arbitrary shape, and are easy to process.

It is a longitudinal section showing the whole side through holder concerning a first embodiment of the present invention. It is a partial expanded longitudinal cross-sectional view of the side through holder which concerns on 1st embodiment of this invention. It is a partial expanded longitudinal cross-sectional view of the side through holder which concerns on 2nd embodiment of this invention.

  The configuration of the present invention will be described below based on the first embodiment shown in FIG. 1 and FIG. The side through holder 1 includes a holder body 2, a housing 3, and a coolant supply nozzle 4. A mounting hole 2c for holding a cutting tool is formed on the front end surface 2a of the holder body 2, and a tapered portion 2d attached to the main shaft of a machine tool such as an NC lathe or a machining center is formed on the rear end surface 2b side. ing. A screw portion 5, a housing mounting portion 6, and a groove portion 7 are sequentially formed on the outer peripheral surface between the front end surface 2a of the holder body 2 and the tapered portion 2d. The groove portion 7 is a portion that is gripped by the manipulator of the tool changer.

  A radial coolant channel 8 is formed on the outer peripheral surface of the housing mounting portion 6 of the holder body 2, and is connected to a coolant channel 9 formed along the central axis. The axial coolant passage 9 communicates with the blade mounting hole 3. Further, a total of six annular recesses 11 for fitting and mounting the seal ring 10 are formed on the outer peripheral surface of the housing mounting portion 6 before and after the coolant passage 8 in the radial direction. Yes.

The housing 3 is fitted and mounted on the outer peripheral surface of the housing mounting portion 6 of the holder body 2 via a bearing 12 so as to be freely rotatable. The housing 3 is fixed to the main body side of the machine tool. A spacer 13, an end face plate 14, and a stopper ring 15 are attached to the outer peripheral surface of the holder main body on both ends of the housing 3, and movement of the housing 3 in the axial direction is restricted.
An annular port 16 is formed on the inner peripheral surface of the housing 3 so as to face the coolant passage 8 in the radial direction of the holder body 2 and communicate with it.
Further, the annular port 16 is connected to a coolant passage 18 of the coolant supply nozzle 4 mounted on the outer peripheral surface of the housing through a radial coolant passage 17.

  Further, packings 19 are mounted on the inner sides of the bearings 12 on both ends between the outer peripheral surface of the holder body 2 and the inner peripheral surface of the housing 3, and a coolant reservoir chamber 20 is further provided on the inner side of the packing 19. Is formed. A drain passage 21 extending from the chamber 20 to the outer peripheral surface is formed at a position corresponding to the coolant reservoir chamber 20 of the housing 3.

  Next, an operation mode of the side through holder 1 configured as described above will be described. The taper portion 2d on the rear end surface 2b side of the holder body 2 is mounted on the spindle of the machine tool, and a cutting tool (not shown) such as a drill is fitted and mounted in the mounting hole 2c on the front end surface 2a side. It is fixed by the mechanism. When processing the work material, the holder main body 2 and the cutting tool attached to the holder main body 2 rotate integrally.

When a high-pressure coolant arbitrarily set in the range from 7 MPa to 30 MPa is supplied to the coolant supply nozzle 4 from such a state, the coolant flow path 18, the radial flow path 17 of the housing 3, the annular port 16, the holder body 2 is supplied to the coolant supply hole of the blade mounted in the mounting hole 2c via the radial flow path 8 and the axial flow path 9. And a coolant is supplied to a cutting site | part from a blade edge surface through the flow path in a blade tool.

  In this embodiment, a total of six seal rings 10, three on each side, are disposed between the housing 3 that is a fixed body and the holder main body 2 that is a rotating body with the radial coolant flow path 8 interposed therebetween. doing. Therefore, although a sealing property is ensured between the outer peripheral surface of the seal ring 10 and the inner peripheral surface of the housing 3, friction occurs between the two. Accordingly, the sealing performance is impaired as the usage time elapses, and therefore the seal ring 10 needs to be periodically replaced.

The coolant supply pressure is set to be much higher than in the conventional case. In addition, when the sealing performance due to wear of the seal ring 10 is impaired, the coolant leaks into the coolant reservoir chamber 20. And here, it is collect | recovered actively as a drain from the drain channel | path 21. FIG. Therefore, the coolant is not scattered around the machine tool, and the work environment can be kept good.

  As described above, the coolant reservoir chamber 20 is provided outside the seal structure portion, and the coolant is positively recovered as a drain from the drain passage 21, whereby the coolant can be supplied at a high pressure of 30 MPa. As a result, the coolant can be directly supplied to the contact portion between the cutting tool and the work material, and the cooling effect between the cutting tool and the work material is excellent. Is possible. Moreover, the processing speed can be increased, and excellent and efficient processing is possible. In addition, the high-pressure coolant cuts off the cut chips with a short dimension, and there is an effect that the chips can be easily handled and processed.

  Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the seal structure is a labyrinth seal structure from the seal ring 10 of the first embodiment. Others are the same as those in the first embodiment. The labyrinth seal structure has an L-shaped small piece inner block 22 that is externally fitted on the outer peripheral surface of the holder body 2, and an inverted L-shaped small piece outer block 23 that is internally fitted on the inner peripheral surface side of the housing 3. As a whole, a labyrinth-like gap of several microns is formed between the blocks 22 and 23 as a whole.

A radial channel 24 and an annular port 27 communicating with the radial coolant channel 8 of the holder body 2 are formed in the block 22a on the holder body 2 located in the center. Further, a radial flow path 26 communicating with the annular port 16 on the housing 3 side is formed in the block 23a on the housing 3 side located in the center.
Further, a packing 19 is fitted on the outer peripheral surface of the holder body 2 between the outermost blocks 22 and 23 and the bearing 12 via a holding ring 24. A coolant reservoir chamber 25 is formed on the inner peripheral surface side of the holding ring 24. The retaining ring 24 has a radial drain passage 26 for allowing the drain passage 21 provided in the housing 3 and the coolant reservoir chamber 25 to communicate with each other.

With such a labyrinth seal structure, there is no contact between the block 22 on the holder body 2 side that is the rotating body in the labyrinth seal portion and the block 23 on the housing 3 side that is the fixed side, and the seal member The problem of wear does not occur. Therefore, it is possible to set the rotational speed of the machine tool to a high speed of 3,000 rpm or more.
Further, the coolant that has passed through the labyrinth seal portion penetrates into the coolant reservoir chamber 25 and is actively collected to the outside through the drain passages 26 and 21, so that there is no problem of scattering around the machine tool.

Therefore, in the second embodiment, the coolant can be supplied at a high pressure of 7 MPa to 30 MPa, and the rotation speed of the spindle of the machine tool can be increased to 3,000 rpm or higher. The effect of supplying the coolant at a high pressure is the same as in the case of the first embodiment.

  By the way, this invention is not limited to embodiment mentioned above, A suitable change is possible. For example, the number of seal rings 10 and the number of labyrinth blocks 22 and 23 are 6 or 6 sets in total, 3 or 3 sets on each side, but these are one or one set. Alternatively, other plural (plural sets) may be used.

DESCRIPTION OF SYMBOLS 1 ... Side through holder 2 ... Holder main body 3 ... Housing 4 ... Coolant supply nozzle 5 ... Screw part 6 ... Housing mounting part 7 ... Groove part 8 ... Radial direction flow path 9 of a holder main body ... Center axis direction flow path 10 of a holder main body ... Seal ring 11 ... Groove 12 ... Bearing 17 ... Housing radial flow path 19 ... Packing 20 ... Coolant reservoir chamber 21 ... Drain passage 22 ... Holder body side block 23 ... Housing side flock 24 ... Holding ring 25 ... Coolant Reservoir chamber 26 ... Drain passage

Claims (4)

It consists of a holder body that can be fitted with a cutting tool at the front end and a mounting part for a machine tool such as a lathe at the rear end, and a housing that is mounted on the holder body through a bearing so as to be relatively rotatable. The housing has a radial flow path communicating with the coolant supply nozzle and an annular port provided on the inner peripheral surface side, and the holder body is continuous with the radial flow path communicating with the annular port. And an axial flow path communicating with the attachment part of the cutting tool, and a seal member is arranged with an annular port between the holder body and the housing, and packing members are arranged on both sides of these seal members A side through holder characterized in that a drain passage is provided in the housing between both sides of the seal member and the packing member. The side through holder according to claim 1, wherein the seal member is a seal ring. The side through holder according to claim 1, wherein the seal member is a labyrinth seal. The side-through holder according to any one of claims 1 to 3, wherein the coolant is supplied at a high pressure of 7 MPa to 30 MPa.

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