JP4807491B2 - Machine tool spindle structure - Google Patents

Description

  The present invention relates to a spindle structure of a machine tool that enables oil mist injection from a tool tip during semi-dry machining.

  Spindle-through machine tools that supply machining fluid from the tip of a rotating tool used to supply a large amount of water-soluble machining fluid at a high pressure, so there was no supply failure. There is also a demand for semi-dry processing using oil mist.

An example of the above-described spindle-through machine tool will be described with reference to FIG.
A draw bar 2 having a shaft hole 2 a is arranged in the main shaft 1 so as to be movable in the axial direction, and a sleeve 3 is connected to the tip of the draw bar 2. A collet 5 is disposed on the outer peripheral side of the sleeve 3. In addition, the main shaft 1 has a gap that is continuous in the axial direction around the draw bar 2, and the gap serves as an air supply path 4. In addition, a disc spring 6 whose rear side is fixedly supported is disposed in the gap, and a connecting member 7 fixed to the draw bar 2 is connected to the front end of the disc spring 6. As a result, the rearward tensile force of the disc spring 6 is transmitted to the draw bar 2 via the connecting member 7. The tool holder 20 has a fitting portion 21 that is fitted in a storage hole 1 a formed at the tip of the main shaft 1, and a locking portion 21 a is formed on the inner peripheral side of the fitting portion 21. The tool holder 20 includes a machining liquid supply pipe 23 that communicates with the shaft hole 2 a of the draw bar 2, and a shaft hole 20 a that communicates with the machining liquid supply pipe 23 is formed on the distal end side of the tool holder 20. The collet 5 has a locking portion 5a that can be engaged with the locking portion 21a on the distal end side, and operates by movement of the draw bar 2 in the axial direction.

  That is, in the above structure, when the draw bar 2 is moving forward, the engagement between the locking portion 5a of the collet 5 and the locking portion 21a of the tool holder 20 is released, and the tool holder 20 is engaged with the main shaft 1. It has become free. On the other hand, when the draw bar 2 is moved backward, the locking portion 5 a of the collet 5 and the locking portion 21 a of the tool holder 20 are engaged, and the tool holder 20 is fixed to the main shaft 1. The water-soluble machining fluid is supplied from the shaft hole 2 a of the draw bar 2 to the cutting edge of a tool (not shown) through the shaft hole 23 a of the machining fluid supply pipe 23 and the shaft hole 20 a of the tool holder 20. Further, the discharge of chips is eliminated by the air ejected to the tool tip through the air supply path 4 and through the gap of the main shaft 1.

By the way, when adopting semi-dry machining, there is a method of discharging oil mist from a nozzle close to the tool and injecting it to the machining point. However, if it is adopted in a machine tool such as drilling, chips will be discharged. In order to become a problem, it is necessary to supply oil mist from the tip of the tool.
Conventionally, there are two known methods for supplying oil mist. One is a method of supplying the machining fluid misted by the semi-dry unit to the rotating spindle. The second is equipped with a mist generating mechanism inside the main shaft, generates mist in the rotating main shaft, and discharges it from the tool tip immediately after generation (see Patent Document 1).
JP-A-9-66437

  However, in the first method described above, in order to generate mist outside the machine and supply it to the rotating spindle, there is a large loss due to the piping loss and the centrifugal force due to rotation, and it is necessary to supply a larger amount of oil. . Further, the second method has an advantage that the loss is small because mist is generated inside the rotating spindle and immediately discharged from the tool. However, there is a problem that the internal structure is complicated and the system becomes very expensive. Further, there is a problem that the mist is easily supplied without being miniaturized and the mist becomes non-uniform.

  The present invention has been made against the background of the above circumstances, and a spindle structure of a machine tool capable of generating fine mist in a spindle and supplying oil mist from a tool tip with a simple structure using a conventional structure. The purpose is to provide.

That is, among the main shaft structures of the machine tool of the present invention, the invention according to claim 1 is characterized in that a draw bar having a shaft hole serving as an oil supply passage for mist is axially provided in a main shaft to which a tool holder is detachably attached at the tip. The mist air supply path is formed along the axial direction in a gap provided between the inner peripheral surface of the main shaft and the outer peripheral surface of the draw bar. A collet member that moves in accordance with the movement of the draw bar to engage and disengage the tool holder is disposed on the outer peripheral side near the tip end side of the draw bar , and a sleeve for operating the collet member is provided. the tip is coupled to expose the outer surface exposed space porous material communicating with the drawbar shaft hole is formed outside the inner peripheral side and the drawbar of the sleeve Cage, said sleeve having a sleeve communicating portion communicating with said exposed space between the inner peripheral surface to the mist air supply path and the exposed space in contact, the exposed space, extends in front of the porous body mist The tool holder is provided with a shaft hole serving as a mist supply path, and the tool holder shaft hole communicates with the mist transfer path.

According to a second aspect of the present invention, the main shaft structure of the machine tool according to the first aspect of the invention is characterized in that the sleeve is fixed to the outer peripheral portion on the front end side of the draw bar .

Invention of the spindle structure of a machine tool according to claim 3, wherein the organic in the invention described in claim 2, the gap the between the inner peripheral surface of the sleeve and the outer peripheral surface of the porous body constituting a part of the exposed space and is, to the clearance, the air from the mist air supply passage is characterized by being configured so as to be supplied.

The invention of the spindle structure of the machine tool according to claim 4 is the invention according to any one of claims 1 to 3, wherein the air supply path for mist is formed on an outer peripheral side of the draw bar . air supply passage is characterized in that through the collet vent portion formed around void or the collet of the collet member are those leading to the exposed space.

  That is, according to the present invention, the oil is supplied through the shaft hole of the draw bar, and the oil flows out to the surface through the porous body connected to the draw bar to form microdroplets or a liquid film. The air flowing through the air supply path flows into the space where the outer surface of the porous body is exposed, and flows so as to contact the outer surface. The effluent on the surface of the porous body is entrained in the air flow, and remains as a fine droplet, or further divided into fine droplets and mixed into the air. As a result, a stable and minute oil mist can be obtained immediately without generating large processing oil droplets. The mist is supplied to the shaft hole of the tool holder through the mist transfer path, and is further injected from the tool tip through the tool. The air in the air supply path is supplied so as to reach the space where the outer surface of the porous body is exposed through the periphery of the collet member and the sleeve arranged in the main shaft, or through the communication portion formed in these.

Further, a gap is formed between the inner peripheral surface of the sleeve disposed on the outer peripheral side of the porous body and the outer peripheral surface of the porous body, and the air supply path supplies air to the gap. If this is done, the cross-sectional area through which the air flows becomes smaller, the air flow is accelerated, and the mist is generated more smoothly. In addition, although air is normally provided as gas which produces | generates mist, you may use gas, such as nitrogen, oxygen, a carbon dioxide, as needed.

  For the porous body used in the present invention, foam metal, foam ceramic, sintered filter, resin filter, metal fiber filter, or the like is used. However, the present invention is not limited to the porous material described above, and may be a porous material made of other materials. However, the porous body needs to be able to move the fluid supplied from the fluid supply path for liquid droplets to the liquid outflow surface of the outflow portion, and the movement of the liquid is achieved by having continuity in the porous body.

  In addition, the size and density of the pores formed in the porous body are not limited to specific ones, but the liquid for droplets flows out evenly on the liquid outflow surface to form sufficiently small droplets or liquid film You may decide to do. For example, the hole size may be 0.05 to 0.1 mm in terms of the equivalent circle diameter. When oil flows out from the pores of such a size as a liquid for droplets to form an oil film, it is expected to have a thickness of about 0.01 to 0.05 mm. This thickness is the thickness that is expected to be maintained by blowing the gas stream.

The flow rate of the gas flow is not particularly limited as the present invention. There is no problem at a flow rate of about 800 to 1200 m / sec. The gap further increases the speed, and for example, the speed can be increased to reach more than 1 to 10 times. The oil droplets blown off from the porous body and mixed into the air are considered to have a diameter of about 0.05 to 0.1 mm at the time of peeling from the above-mentioned size. In addition, it is expected to have a diameter of about 0.01 to 0.02 mm, which is about 1/5 by receiving a shearing force in the air flow. However, the above numerical values are merely examples, and it is needless to say that the present invention is not limited to a specific range.

In the present invention, since the collet is operated by the axial movement of the draw bar and the tool holder is engaged and disengaged, the original function of the draw bar is not impaired, and the tool holder can be easily attached and detached.
The structure of the sleeve and the collet member is not limited to a specific one in the present invention, and an appropriate structure can be used as long as it can fulfill its function.

  As described above, according to the spindle structure of the machine tool of the present invention, the draw bar having the shaft hole serving as the oil supply passage for mist is provided along the axial direction in the spindle in which the tool holder is detachably attached to the tip. The mist air supply path is formed along the axial direction so as to be movable, and is operated along with the movement of the draw bar on the outer peripheral side in the vicinity of the tip end side of the draw bar. A collet member for engaging and disengaging is disposed, and further, a porous body communicating with the draw bar shaft hole is connected to an end side of the draw bar with an outer surface exposed, and the air supply path for mist is The air that moves through the air supply path for mist in communication with the exposed space where the outer surface of the porous body is exposed can come into contact with the outer surface of the porous body, and the exposed space The tool holder is provided with a shaft hole serving as a mist supply path, and the tool holder shaft hole communicates with the mist transfer path. A fine oil mist can be generated in the main shaft and supplied to the tool tip using the draw bar used in the above. Moreover, since it can be constructed using a conventional structure and the mist generating mechanism can be configured with a simple structure, oil mist can be discharged from the tool tip without causing a significant increase in manufacturing cost. Specifically, air and oil are transported to the tip of the rotating spindle through different paths, mixed and discharged at the tip of the spindle, and the principle of mist generation is to create an oil film on the surface of the porous body. Since it is a simple structure that blows it away with air, it can be constructed with an inexpensive structure with few failures. What is necessary is just to comprise the path | route of air so that the air which passes along an air supply path may be guide | induced to the production | generation part of a mist using the air supply path used for supply of cleaning air. The oil supply path can utilize the shaft hole of the draw bar used for supplying the machining fluid.

Below, one Embodiment of this invention is described based on FIG. The same structure as that of the conventional example will be described with the same reference numerals.
The machine tool spindle 1 has an attachment hole 1a for attaching the tool holder 20 at the tip, and a draw bar 2 for operating the attachment / detachment of the tool holder 20 is arranged along the axial direction. An air supply path 4 is formed in the gap. Further, the shaft center of the draw bar 2 is formed with a shaft hole 2a penetrating the tip as an oil supply path.
A connecting member 7 is fixed to the outer peripheral portion of the draw bar 2, and a disc spring 6 that supports and fixes the rear side is disposed in a space behind the connecting member 7. The disc spring 6 has a front end fixed to the connecting member 7 in a state having a tensile force. Thereby, the tensile force to the rear of the disc spring 6 is transmitted to the draw bar 2 via the connecting member 7.

Further, a cylindrical sleeve 3 having a length exceeding the mounting hole 1a is fixed to the outer peripheral portion of the tip of the draw bar 2. Further, a porous body 10 communicating with the shaft hole 2a is connected to the tip of the draw bar 2 so as to be positioned on the inner peripheral side of the sleeve 3, and the outer surface of the porous body 10 and the sleeve 3 are connected to each other. Has a gap . In the sleeve 3, a plurality of vent holes 3b communicating with the gap are formed along the circumferential direction so as to penetrate the inner and outer circumferences as vent portions. The space 11 including the gap penetrates the front end of the main shaft 1 on the outer peripheral side of the sleeve 3 to constitute a mist transfer path.

The tool holder 20 has a cylindrical fitting portion 21 for fitting into the mounting hole 1a of the main shaft, and has a locking portion 21a protruding on the inner peripheral side on the inner peripheral surface of the front end of the fitting portion 21. is doing.
Further, a machining liquid supply pipe 23 is disposed in the cylindrical hole of the fitting portion 21 along the axial direction, and the tool holder 20 on the front side of the machining liquid supply pipe 23 penetrates to the tip side. Te of the tool shaft hole (not shown) and communicable shaft hole 20 a is formed.
When the tool holder 20 is mounted in the mounting hole 1a, the rear end of the machining liquid supply pipe 23 provided at the center of the tool holder 20 is located in the storage hole 1c, and there is no gap in the sleeve 3. It is inserted and communicates with the space 11.

On the other hand, the sleeve 3 is formed with a bulging portion 3 a that bulges on the outer peripheral side on the outer peripheral surface on the front end side, and a collet 5 is disposed on the outer peripheral side of the sleeve 3. The collet 5 has a locking portion 5a protruding on the outer peripheral side on the outer peripheral surface on the front end side. The locking portion 5a is positioned on the front side, and the locking portion 21a is positioned on the rear side. The parts 5a and 21a can be engaged with each other. Further, the rear end side of the collet 5 is thick, and has a convex portion 5 b that bulges to the outer peripheral side and a convex portion 5 c that bulges to the inner peripheral side, and is formed on the inner peripheral surface of the main shaft 1. The concave groove 1b and the convex portion 5b can be fitted. The groove surface on the front end side of the concave groove 1b is formed with a tapered surface inclined forward so that the inner peripheral side is positioned forward, and the front end surface of the convex part 5b of the collet 5 is tapered tapered rearward. It is formed with a surface. Therefore, the collet 5 can move inward or outward in the radial direction while sliding in an oblique direction by fitting the convex portion 5b and the concave groove 1b through the both tapered surfaces. Further, a large-diameter portion 2b that can contact the convex portion 5c is formed on the outer peripheral surface of the draw bar 2. Further, an urging member 8 is disposed between the rear end of the collet 5 and the connecting member 7 so that forward biasing force can be applied to the collet 5 by the advancement of the connecting member 7. It is configured.

  In addition, the collet 5 is positioned on the inner side of the locking portion 21a when the collet 5 is positioned on the rear side of the bulging portion 3a of the sleeve 3 and in contact with the thin portion of the sleeve 3. Are configured to be unlocked from each other. At this time, the convex portions 5c of the collet are located on the rear side of the large-diameter portion 2b of the draw bar 2 so as not to interfere with each other.

In the above structure, when the tool holder 20 is attached and detached, the draw bar 2 is moved forward in the axial direction against the tensile force of the disc spring 6. Then, after the draw bar 2 has advanced a little, the collet 5 is pushed forward by the urging force of the urging member 8. The collet 5 advances slightly while being moved toward the inner peripheral side in accordance with the tapered shape of the tip surface of the convex portion 5b that contacts the concave groove 1b. At the time of advancement, the sleeve 3 preferentially advances, so that the tip of the collet 5 is located behind the bulging part 3a of the sleeve 3, and the large diameter part 2b of the draw bar 2 is the convex part 5c of the collet 5. Located in front. As a result, the locking portion 5a of the collet 5 is positioned on the inner peripheral side with respect to the locking portion 21a of the tool holder 20 and the mutual engagement is released. As a result, the fitting portion 21 of the tool holder 20 can be removed from the mounting hole 1a, and the fitting portion 21 of the tool holder 20 can be newly inserted into the mounting hole 1a.

  Next, when the mounted tool holder 20 is fixed, the draw bar 2 is moved rearward along the axial direction. Then, the bulging portion 3 a of the sleeve 3 also moves backward with the draw bar 2, enters the inner peripheral side of the collet 5 and pushes the collet 5 up to the outer peripheral side, and the large-diameter portion 2 b of the draw bar 2 becomes the convex portion 5 c of the collet 5. The collet 5 is pushed up to the outer peripheral side. Then, the collet 5 moves slightly backward while being pushed out to the outer peripheral side while following the taper shape of the fitting surface of the convex portion 5b and the concave groove 1b, and the locking portion 5a is locked to the locking portion 21a, and the convex portion 5b fits into the recess 1b. The sleeve 3 is maintained in a state of being pulled by the disc spring 6 through the draw bar 2, and the collet 5 is disposed on the outer peripheral side by the outer peripheral surface of the bulging portion 3 a of the sleeve 3 and the outer peripheral surface of the large-diameter portion 2 b of the draw bar 2. It is pressed and fixed. When the draw bar 2 moves, the porous body 10 is always in the space 11, that is, in the sleeve 3, and does not interfere with other members, and the original function of the draw bar 2 is not hindered.

  When machining is performed in the machine tool in which the tool holder 20 is fixed to the spindle 1 as described above, the spindle 1 and the machining holder 20 are rotated. If oil mist is intermittently discharged at this time, oil is jetted forward through the shaft hole 2a of the draw bar 2 in accordance with this, and impregnated in the pores of the porous body 10. The oil impregnated in the porous body 10 further reaches the outer surface of the porous body 10, and the oil that has flowed out from the surface pores becomes fine oil droplets or an oil film.

On the other hand, in the air supply path 4, air is supplied constantly or in accordance with the discharge of oil mist. Air flows forward through the air supply path 4, passes through the gap around the collet 5, and is further injected into the gap between the sleeve 3 and the porous body 10 through the plurality of vent holes 3 b of the sleeve 3. The air flow is accelerated by the gap , and moves in the space 11 while being in contact with the outer surface of the porous body 10 along the distal end surface from the outer peripheral surface of the porous body 10. As a result, fine oil droplets are effectively peeled from the surface of the porous body 10 one after another, and are entrained in the air to become mist. The oil mist flows forward through the space 11 and moves into the shaft hole 23 a of the machining liquid supply pipe 23. At this time, since the space 11 is surrounded by the sleeve 3, the oil mist surely reaches the shaft hole 23a, further moves from the shaft hole 23a to the shaft hole 20a, and is discharged from the tip of a tool (not shown). Is done. In the mist, fine droplets are stably generated, and thereafter, the mist immediately moves from the tool holder to the tool and is supplied to a processing point (not shown) to give good lubricity and work. This makes it possible to perform semi-dry machining with a machine.
As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to the content of the said embodiment, In the range of this invention, it can change suitably.

It is sectional drawing which shows one Embodiment of this invention. It is a partially expanded sectional view similarly. It is sectional drawing which shows the main shaft structure of the conventional spindle through machine tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main axis | shaft 2 Draw bar 2a Shaft hole 3 Sleeve 3b Vent hole 5 Collet 10 Porous body 11 Space 20 Tool holder 20a Shaft hole 23 Process liquid supply pipe 23a Shaft hole

Claims (4)

A draw bar having a shaft hole serving as a mist oil supply passage is movably disposed along the axial direction in a main shaft to which a tool holder is detachably attached to the tip, and an inner peripheral surface of the main shaft and the draw bar A mist air supply path is formed along the axial direction in a gap provided between the outer peripheral surface and the outer peripheral surface of the draw bar. A collet member for engaging and disengaging the tool holder is disposed , a sleeve for operating the collet member is provided , and a porous body communicating with the draw bar shaft hole is provided at the tip of the draw bar . An outer space is exposed and connected to an exposed space formed on a circumferential side and outside the draw bar, and the sleeve is connected to the inner circumferential surface in contact with the exposed space. Has a sleeve communicating portion that communicates the supply path and the exposed space, the exposed space, the extending forwardly of the porous body constitutes a mist transfer path, the tool holder, the axis hole as the mist supply passage the main shaft structure of the machine tool, characterized in that the provided, in which the said tool holder shaft hole communicating with the mist flow path. The main shaft structure of a machine tool according to claim 1, wherein said sleeve is characterized in that it is fixed to the outer peripheral portion of the distal end side of the drawbar. Wherein an inner peripheral surface of the sleeve is a porous body outer peripheral surface of which a gap which constitutes a part of the exposed space, Yoyo that the said gap, the air from the mist air supply passage is supplied The spindle structure of the machine tool according to claim 2, wherein the spindle structure is configured as follows. The mist air supply passage is formed on the outer peripheral side of the drawbar, the mist air supply passage, on the exposed space through the collet vent portion formed around void or the collet of the collet member The main spindle structure of a machine tool according to any one of claims 1 to 3, wherein

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