JP2016060001A - Machine tool and tool holder unit therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool holder unit and a machine tool for accurately jetting coolant to a machining portion with a simple configuration.SOLUTION: A machine tool includes: a tool holder unit 300 which includes a tool rotary shaft which has a flow passage formed to pass through a rotary shaft, a holder body 302 which is detachably engaged with the tool rotary shaft and has a flow passage formed to be continuous to the tool rotary shaft, a grindstone 105 which is mounted in the tool holder body and is rotated by the rotary shaft, and a cap section 304 which holds the grindstone together with the tool holder body. The machine tool performs inner periphery grinding in a workpiece by the grindstone. The tool holder body is formed in an axial center section and includes a main supply hole to which coolant is supplied from a machine side of the tool machine. The cap section is extended to a surface orthogonal to an axial direction, and includes a recess communicated with the main supply hole and a plurality of branch supply holes communicated with an outer peripheral surface or an outside surface side orthogonal to the axial direction from the recess, and jets coolant from the branch supply holes to a peripheral surface side of the grindstone.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a machine tool and a tool holder unit thereof, and more particularly, to a machine tool including a coolant supply mechanism and a tool holder unit thereof.

  Conventionally, when a workpiece is ground in a machine tool such as a grinder, coolant (grinding fluid) guided and supplied via a predetermined path is sprayed toward a processing site by a grindstone. In particular, as a so-called internal laboratory, in a machine tool for grinding a female screw or the like on its inner periphery using a relatively small grindstone that enters an inner peripheral hole of a cylindrical workpiece or the like, the tool holder side or the work support base side The tip of a coolant nozzle extending from a coolant supply path extending from a predetermined location is arranged toward the processing site, and coolant is jetted from the nozzle (for example, see Patent Document 1).

  Further, in a machining machine tool, a so-called center through is used to supply cutting fluid as coolant to the tip of a tool through a supply hole formed through a shaft center of a tool holder or the like disposed on a spindle. A technique related to the coolant is known (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 8-112746 JP 2003-334738 A

  However, in the conventional example described in Patent Document 1, for example, when the outer peripheral surface of a cylindrical workpiece can be ground, the coolant can be sprayed relatively accurately to the processing site. For example, when grinding the inner peripheral surface of the machine, it is difficult to accurately inject coolant to the machining part because the machining part moves both in the inner circumferential direction and in the vertical direction according to the position of the grindstone. is there. If the angle of the coolant nozzle or the like is controlled by the NC so as to adapt to the processing site, the structure and the control technology are complicated.

In addition, in the conventional example described in Patent Document 2, when a workpiece is cut by a machining center or the like, a coolant (cutting fluid) is easily supplied to the processing portion on the tip side of the cutting tool with a center through structure. When a workpiece is ground with a disc-shaped grindstone mounted so as to be orthogonal, it is difficult to eject the coolant toward the workpiece processing portion by the peripheral end surface of the grindstone. In this case, although it is conceivable to provide the grindstone itself with a supply hole directed from the shaft core portion toward the peripheral end surface, the hardness of the grindstone becomes weak. Moreover, in the structure which uses a porous grindstone and exudes a coolant from the axial center part of a grindstone to the peripheral end surface side, it will receive restrictions, such as selection of a grindstone and a use.

Therefore, there has been a demand for the development of a technique capable of accurately injecting coolant to a processing site when the inner peripheral surface of a workpiece is ground with a grindstone, etc., with a simple configuration.

  The present invention has been made under the circumstances as described above, and its purpose is to accurately inject coolant to a processing site when grinding the inner peripheral surface of a workpiece with a grindstone while having a simple configuration. It is to provide a technology that can.

  In order to achieve the above object, a tool holder unit according to the first aspect of the present invention includes a tool holder body disposed on a rotating shaft, a grindstone attached to the tool holder body and rotated by the rotating shaft, A tool cap for holding the attached grindstone between the tool holder main body and the inner grind of the workpiece by the grindstone, wherein the tool holder main body is formed at an axial center, The holder cap is provided with a main supply hole for supplying coolant from the machine side, and the holder cap extends to a surface orthogonal to the axial direction, and communicates with the main supply hole, and an outer peripheral surface orthogonal to the axial direction from the recess Alternatively, it has a plurality of branch supply holes communicating with the outer surface side, and has a structure in which the coolant is ejected from the branch supply holes toward the peripheral surface side of the grindstone.

The branch supply hole is preferably formed obliquely on the grindstone side from the recess toward the outlet.

In order to achieve the above object, a machine tool according to a second aspect of the present invention is detachably engaged with a tool rotating shaft in which a flow path penetrating the rotating shaft is formed, and the tool rotating shaft. A tool holder is formed so that a flow path is continuous with the tool rotation axis, and the tool holder is attached to the tool holder main body disposed on the rotation axis and the tool holder main body, and is rotated by the rotation axis. And a tool cap for holding the attached grindstone between the tool holder body and grinding the inner periphery of the workpiece with the grindstone, the tool holder body is formed at the shaft center portion. And a main supply hole through which coolant is supplied from the machine side of the machine tool, wherein the holder cap extends in a plane perpendicular to the axial direction and communicates with the main supply hole, and the axial direction from the recess straight And a plurality of branch supply hole communicating with the outer peripheral surface or the outer surface side, a machine tool, characterized by ejecting the coolant from the branch supply holes toward the peripheral surface of the grinding wheel.

  ADVANTAGE OF THE INVENTION According to this invention, although it is simple structure, when grinding the internal peripheral surface of a workpiece | work with a grindstone etc., the technique which can inject a coolant precisely to a process part can be provided.

It is a figure showing the schematic structure of the grinding device to which the present invention is applied. It is a functional block diagram which shows the structure of the grinding device to which this invention is applied. It is a figure which shows the A-axis rocking | fluctuation control in the grinding apparatus shown in FIG. It is a figure which shows the 1st path | route of the grinding fluid in the grinding apparatus shown in FIG. It is a figure for demonstrating the ejection method of the grinding fluid from the 1st path | route of the grinding fluid shown in FIG. It is a figure which shows the 2nd path | route of the grinding fluid in the grinding apparatus shown in FIG. It is a figure which shows the tool holder unit with a conical cap as a comparative example of this invention, (a) is the bottom view, (b) is the front view, (c) is the perspective view. It is a figure for demonstrating the subject by the ejection of the grinding fluid from the 1st path | route of the grinding fluid shown in FIG. 4, and the tool holder unit with a conical cap shown in FIG. It is a figure showing a schematic structure of a grinding device concerning an embodiment of the present invention. It is a figure which shows the tool holder unit which concerns on embodiment of this invention, (a) is the bottom view, (b) is the front view, (c) is the perspective view. It is a figure which shows the structure of the cap part of the tool holder unit which concerns on embodiment of this invention, (a) is the bottom view, (b) is the front view, (c) is AA sectional drawing of the front, (D) is the perspective view of the front, (e) is the top view.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a diagram illustrating a schematic configuration of a grinding apparatus to which the present invention is applied, FIG. 2 is a functional block diagram illustrating a configuration of a grinding apparatus to which the present invention is applied, and FIG. 3 is a grinding apparatus illustrated in FIG. It is a figure which shows peristaltic control of the A axis | shaft in FIG. As shown in FIG. 1, the grinding apparatus 100 according to the present embodiment includes a bed (not shown), a processing base unit 104 placed on the bed, and a predetermined direction (XYZ3 axes) with respect to the processing base unit 104. ), A head side XYZ 3-axis drive device (including a column not shown) 108 for driving the grinding wheel shaft head 106 in the XYZ 3-axis direction, and a grinding device 100. A workpiece support 110 and a dresser 112 provided on the machining base 104 are provided. Further, as shown in FIG. 2, the grinding apparatus 100 of the present embodiment includes motor drivers 201, 202, 203, 204, and 205 that control driving in the respective axial directions of XYZ-A-C, and these motors. A CNC (computer numerical control) device 200 that controls the drivers 201, 202, 203, 204, and 205 and numerically controls the rotational speed and feed rate of each axis and includes an interpolation function thereof is provided. The computer numerical control device 200 has a built-in machining program capable of inputting data for the numerical control (workpiece specifications) in, for example, an interactive format. That is, as shown in FIG. 2, the grinding apparatus 100 can control in the 5 (axis) direction composed of the 3 axis directions of XYZ and the 2 (axis) directions of A and C. Motor drivers 201, 202, and 203 for driving the head 106 in the X, Y, and Z axis directions, the respective motors 211, 212, and 213, and the processing base portion 104 are connected to the A axis via the A axis motor 214 and the bearings 214A and 214B. Motor driver 204 that pivots in the direction, motor driver 205 that rotates the work axis WAX equipped with the chuck mechanism CH in the C-axis direction, tool spindle driver 206 that rotationally drives the grindstone shaft 107, the tool spindle motor 216, and the dresser A driver 207, its motor 217, and a CNC (computer numerical control) device 200 are provided. Motor numerical control) device 200, according to a predetermined machining program, such as by driving and controlling the motor driver 201 to 207 in each axial direction, the workpiece W is machined (ground) to the desired female screw shape. Further, the grindstone 105 is dressed by the dresser 112 in accordance with the shape of the female screw to be processed. Even when the grindstone that has been used once is reused, the dresser 112 may perform truing or dressing (reshape or sharpening) of the grindstone 105, and truing (reshape) may be simply referred to as dress. Shall be included. For convenience, the vertical direction in FIG. 1 is the Z-axis (feed axis) direction, and the direction parallel to the paper plane is the X-axis (feed axis). Is in the state (direction) represented in the figure, the axis that gives the workpiece rotation around the X axis is the A axis (rotary axis) direction, and the axis that gives rotation around the Z axis is the C axis (rotary axis) Defined as direction.

Further, as described above, the processing base portion 104 is configured to be rotatable with respect to the grindstone shaft head 106 as shown in FIG. The swivelable angle is, for example, −α degrees to α degrees (for example, α = 25), assuming that the direction of the grindstone shaft 107 coincides with the Z axis is 0 degrees for convenience and the counterclockwise direction is the positive direction. is there. However, the present invention is not limited to this, and an angle necessary for screw grinding may be included. The direction in which the machining base portion 104 turns is defined as the A direction described above.

  A grindstone 105 is supported on the grindstone shaft head 106 by a grindstone shaft 107 and is rotated by a tool spindle motor 216. A grinding wheel head drive (servo) motor 212 provided in the head side XYZ triaxial drive device (including a column not shown) 108 is supplied from a pulse distribution circuit (not shown) in the CNC (computer numerical control) device 200. It is controlled and driven by a motor driver 203 that operates based on a distributed control pulse, for example, and feeds the grinding wheel head 106 in the Z direction. When feeding z in the Z direction, the motor driver 202 also feeds in the Y direction by sin α times, and the motor driver 205 is divided by the number of times the screw lead to be machined is divided by the lead length of the screw to be machined on the ZY plane. To give C-axis rotation. By the three-axis simultaneous control in which these operations are performed in synchronization, the grinding apparatus 100 can process a female screw continuous in the vertical direction on the inner peripheral surface of the work W in the deep hole. Further, a position detector (not shown) such as an encoder detects the turning position of the machining base portion 104 via the rotation angle of the A-axis motor 214, and this detected value is sent via a sensor controller (not shown). Input to a CNC (computer numerical control) device 200.

  Each of the CNC (computer numerical control) devices 200 is not shown, but a central processing unit (CPU) for controlling and managing the entire grinding device 100, a memory, an interface for exchanging data with the outside, and a command from the CPU. Accordingly, a function of distributing and sending drive commands for a plurality of axes to each axis is provided. For example, a sensor controller is connected to the CPU via an input / output device such as a dedicated or general-purpose digital interface or an AD / DA converter, and the sensor controller is controlled by the CPU. Further, an input device (not shown) for inputting control data and the like is connected to the interface, and the above-described motor group is connected to the command distribution mechanism to each axis via motor drivers 201 to 207. Yes. The memory stores a machining program for machining the workpiece W, other data, and the like.

Next, the supply path and method of the grinding fluid (coolant) in the grinding apparatus 100 of this embodiment will be described. Here, in order to facilitate understanding of the present invention, as a comparative example, a grinding fluid (coolant) supply path and method in a conventional grinding apparatus will be briefly described with reference to FIGS. As shown in FIGS. 4 and 5, the grindstone 105 is supplied from the coolant nozzle 402 that is supplied from the A-axis motor 214 side and provided in the hole 110 </ b> A of the work support base 110 through the flow path in the processing base portion 104. Grinding fluid (coolant) is ejected toward the machining part of the female thread of the workpiece W (first supply path P1).
However, the coolant nozzle 402 that rotates in synchronization with the workpiece W is fixed so as to stand upright, for example, 90 degrees. Therefore, when the turning angle α and the distance to the grindstone 105 are just suitable, the processing site by the grindstone 105 is processed. Although the coolant can be supplied accurately, for example, when the grindstone 105 is processed at an upper position indicated by the arrow U in FIG. 8, the coolant cannot be accurately supplied to the processing site by the grindstone 105.

Therefore, the grinding apparatus 100 of the present embodiment employs the second supply path P2 of the grinding fluid (coolant) in addition to the first supply path P1 of the grinding fluid (coolant) described above. FIG. 6 is a view showing a second supply path P2 of the grinding fluid in the grinding apparatus 100 of the present embodiment. In other words, the head side XYZ three-axis drive device (including a column not shown) 108 is provided so as to penetrate the grinding wheel shaft head 106, the grinding wheel holder (quill) H, and the shaft core portion of the grinding wheel shaft 107 (center). It is desirable that the grinding fluid (coolant) can be ejected from the supply hole of the through hole toward the portion to be processed by the grindstone 105. However, even if, for example, a through hole is provided to the shaft core portion of the cap member (not shown) of the grindstone holder H and the grinding liquid (coolant) is ejected from the through hole, the grindstone 105 is orthogonal to the grindstone shaft 107. Therefore, it is difficult to eject the grinding liquid (coolant) toward the portion processed by the grindstone 105. In this case, as a cap member of the grindstone holder H, as shown in FIG. 7, it is also conceivable to provide a conical cap member EC having a top on the tip side. According to the conical cap member EC, for example, the grinding fluid (coolant) ejected from the coolant nozzle 402 toward the upper grindstone 105 via the first path P1 collides with the top and the conical surface. In combination with the centrifugal force, it is possible to flow through the conical surface and disperse it radially around the peripheral surface of the grindstone 105.

However, as described above, when the grindstone 105 is machined at the upper position indicated by the arrow U in FIG. 8, the coolant cannot be accurately supplied to the machining site by the grindstone 105. In the case of circumferential grinding (such as internal thread grinding), the problem of accurately supplying coolant to the machining site cannot be solved regardless of the height of the grinding wheel.

Then, since this inventor devised the structure of embodiment of the tool holder unit of this invention described below, it demonstrates with reference to FIGS. 9-11. FIG. 9 is a diagram showing a schematic configuration of a grinding apparatus according to an embodiment of the present invention. FIG. 10 is a view showing a tool holder unit according to an embodiment of the present invention, in which (a) is a bottom view thereof, (b) is a front view thereof, and (c) is a perspective view thereof. FIG. 11 is a diagram showing a detailed configuration of the cap portion of the tool holder unit according to the embodiment of the present invention, in which (a) is a bottom view thereof, (b) is a front view thereof, and (c) is a front view thereof. -A sectional view, (d) is a front perspective view thereof, and (e) is a plan view thereof. The grinding apparatus 100 of this embodiment has a tool holder unit 300 as shown in FIG. The tool holder unit 300 includes a holder main body 302 and a cap portion 304 as shown in FIGS. The holder main body 302 has a grindstone shaft head side mounting portion 306, a flange portion 308, and a quill portion 310 having a long cylindrical shape. The grindstone 105 is used by being fixed to the grindstone shaft 107 by being attached to the quill portion 310 of the holder main body 302 and being sealed and fixed by the cap portion 304. For example, as shown in FIGS. 11A, 11B, 11C, and 11C, the cap portion 304 is provided with guide holes 304a in a 6-perimeter arrangement on the circumference. The grinding fluid (coolant) that has entered the recess 304H at the tip temporarily accumulates in the recess 304H, and is brought close to the end on the peripheral surface side by the oil force of the grinding fluid (coolant) and the centrifugal force of the tool rotation, so that a guide hole 304a is provided. It flows inside and is guided to the processing site near the outlet of the guide hole 304a.

That is, in the grinding apparatus having the second path P2 described above, the fixed pipe (provided with the head-side XYZ three-axis drive device (including a column not shown) 108 is provided with coolant necessary for grinding by the grindstone 105. When supplied from a not shown), the coolant reaches the holder main body 302 through the tool rotation shaft (grinding wheel shaft) 107 housed in the grinding wheel shaft head 106 and the approximate center of the tool holder unit 300. Next, the coolant accumulates in the depression 304H from the hole in the center of the cap portion 304 through a flow path provided in the holder main body 302, and the end on the peripheral surface side is caused by the oil force of the grinding fluid (coolant) and the centrifugal force of the tool rotation. , And flows through the guide hole 304a and is guided to the processing site near the outlet of the guide hole 304a. In the grinding apparatus 100 of the present embodiment, the grindstone 105 uses a conventional grindstone in which no holes for flowing coolant are formed. There are many types of binders that form the shape of the grindstone 105, and the present invention is naturally applicable to grindstones made of non-porous binders.
By jetting the coolant flow Cflow from the cap portion 304 of the tool holder unit 300 at the time of machining, the coolant sprayed from the coolant nozzle 402 provided at the bottom of the workpiece support base 110 toward the machining site becomes unnecessary, or It becomes possible to use together with the coolant flow Cflow. The workpiece W is rotatably held by the chuck CH of the workpiece support 110, and an internal thread can be processed on the inner peripheral surface.

  In the grinding apparatus 100 of the present embodiment, since the coolant flow is ejected from each of the guide holes 304a provided in six circumferences on the circumference of the cap portion 304, the coolant flow depends on the shape and depth of the part to be processed. Therefore, it can be applied to precious creep feed grinding.

  In the embodiment described above, the present invention is applied to the processing of the internal thread by the inner circumference grinding (internal grinding), but it is needless to say that the present invention is not limited to this. The present invention can also be applied to, for example, outer peripheral grinding (grinding) using a grindstone.

100 grinding device, 104 processing base, 105 grinding wheel,
106 grinding wheel head, 107 grinding wheel shaft,
108 head side XYZ 3-axis drive device, 110 work support base,
112 dresser, 200 CNC (computer numerical control) device,
201, 202, 203, 204, 205 Motor driver,
206 Tool spindle driver, 207 Dresser driver,
214 A-axis motor, 214A, 214B bearing,
216 Tool spindle motor, 217 motor, W workpiece,
CH chuck mechanism, WAX workpiece axis, P1, P2 coolant supply path 300 tool holder unit, 302 holder body, 304 cap part,
306 Grinding wheel shaft head side mounting part, 308 Flange part,
310 Quill, 304a Guide hole, 304H depression

Claims (4)

A tool holder body disposed on the rotating shaft, a grindstone attached to the tool holder body and rotated by the rotating shaft, and a holder cap for clamping the attached grindstone between the tool holder body, A tool holder unit in a machine tool that performs inner peripheral grinding of a workpiece with the grindstone, wherein the tool holder main body is formed in an axial center portion, and includes a main supply hole through which coolant is supplied from the machine side of the machine tool, The holder cap extends in a plane perpendicular to the axial direction, and has a hollow portion communicating with the main supply hole, and a plurality of branch supply holes communicating from the hollow portion to the outer peripheral surface or the outer surface side perpendicular to the axial direction. The tool holder unit has a structure for ejecting the coolant from the branch supply hole toward the circumferential surface of the grindstone. 2. The tool holder unit according to claim 1, wherein the branch supply hole is formed obliquely on the grindstone side from the recess toward the outlet. 3. A tool rotation shaft in which a flow path penetrating the inside of the rotation shaft is formed, and a tool holder that is detachably engaged with the tool rotation shaft and formed so that the flow path is continuous with the tool rotation shaft, The tool holder includes a tool holder main body disposed on a rotating shaft, a grindstone attached to the tool holder main body and rotated by the rotating shaft, and a holder cap for clamping the attached grindstone between the tool holder main body and the tool holder main body. The tool holder main body is formed in an axial center portion, and includes a main supply hole through which coolant is supplied from the machine side of the machine tool, and the holder The cap has a recess that extends in a plane orthogonal to the axial direction and communicates with the main supply hole, and a plurality of branch supply holes that communicate from the recess to the outer peripheral surface or the outer surface side orthogonal to the axial direction. , Machine tool, characterized in that for ejecting the coolant from the branch supply hole toward the circumferential surface of the grinding wheel. 4. The machine tool according to claim 3, wherein the branch supply hole is formed obliquely on the grindstone side from the recess toward the outlet. 5.

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