JP4859033B2 - Machine tool spindle equipment - Google Patents

Description

  The present invention relates to a spindle device for supporting a floating tool in a machine tool.

  Generally, when machining a plurality of journal parts of the engine camshaft and crankshaft using a machine tool, a line boring bar equipped with a floating mechanism that can move the axis of the spindle and the axis of the tool relative to each other Machining is performed using the tool. Since the tool supported by the floating mechanism is long, the spindle is rotated while supporting the tool by a tool support means such as a support bush or a bar support sleeve for supporting the tool when machining. As a result, the cutting tool provided on the outer peripheral surface of the line boring bar rotates to process the journal portion of the workpiece.

A machining center incorporating such a floating mechanism is described in Patent Document 1. The machining center described in Patent Document 1 uses an Oldham joint as means for floatingly supporting a line boring bar.
JP 2003-305605 A

  The spindle device described in Patent Document 1 employs a holder incorporating an Oldham coupling, which is one type of floating support means. By using this holder, it is possible to absorb the relative position error between the axis of the main spindle and the axis of the line boring bar, which is the feature of the floating method. When the line boring bar is inserted into the sleeve before performing, there is a possibility that the axis of the line boring bar and the axis of the sleeve are inclined due to floating. This inclination may cause the line boring bar to collide with the wall surface around the support hole in the bar support, and the line boring bar, the main shaft, and the sleeve may be damaged. In addition, even if it is not damaged, the contact portion between the line boring bar and the sleeve may be unevenly worn due to wear of the line boring bar and the sleeve, which may adversely affect the processing accuracy.

  Therefore, in order to solve these problems, the present invention enables a tool equipped with a floating mechanism to be smoothly inserted into and removed from a tool support means and a workpiece before machining in the spindle device of a machine tool, and is a feature of the floating method. An object of the present invention is to provide a spindle device for a machine tool capable of absorbing a relative position error between the axis of the spindle and the axis of a line boring bar.

  In order to solve the above problems, the invention according to claim 1 is directed to a spindle device of a machine tool that supports a machining tool in a floating manner with respect to the spindle, and a flow path for fluid supply is provided inside the spindle. And a support means for supporting a support end of the processing tool via a fluid bearing that applies a fluid pressure of the fluid supplied from the flow path, and the fluid bearing of the support means is a thrust bearing, The thrust bearing is composed of a front thrust bearing portion that applies fluid pressure to the machining tool in the axial direction forward of the main shaft and a rear thrust bearing portion that applies fluid pressure to the axial direction rearward of the main shaft, and the front thrust bearing portion or The gist is that the flow path is provided with switching means capable of interrupting the fluid pressure acting on one of the rear thrust bearing portions.

  According to a second aspect of the present invention, in the main spindle device of the machine tool according to the first aspect, the flow path not having the switching means in the flow path is orthogonal to the axial direction of the main spindle with respect to the processing tool. The gist of the present invention is to provide a radial bearing that applies a fluid pressure in the direction of movement.

  The gist of the invention described in claim 3 is that, in the spindle device of the machine tool according to claim 1 or 2, an adjustment mechanism capable of adjusting the fluid pressure of the fluid acting on the fluid bearing is provided.

  According to a fourth aspect of the present invention, in the spindle device of the machine tool according to the first or second aspect, an adjustment mechanism is provided that can adjust the fluid pressure of the fluid acting on the fluid bearing for each flow path. The gist.

According to a fifth aspect of the present invention, in the method for supporting a line boring bar as the machining tool on the main spindle device of the machine tool according to the first aspect, the work tool is spaced apart on the same axis as the main spindle. When the line boring bar is inserted into and removed from the line boring bar support hole, the fluid pressure is shut off by the switching means, and the line boring bar is fixedly supported to the main shaft, and the fluid pressure is shut off by the switching means when machining a workpiece. The gist of the present invention is a line boring bar support method in which the line boring bar is supported without floating.

  According to the first aspect of the present invention, the thrust bearing is constituted by a front thrust bearing portion that applies fluid pressure to the axial front of the main shaft and a rear thrust bearing portion that applies fluid pressure to the rear of the main shaft in the axial direction. By making it possible to shut off the fluid pressure acting on either one, the posture when inserting the work tool into the workpiece or bar support can be fixed by abutting and supporting straight along one reference surface of the bearing Therefore, the machining tool, the spindle and the support hole can be prevented from being damaged or worn without causing an inclination between the axis of the machining tool and the axis of the support hole of the bar support.

  According to the second aspect of the present invention, in addition to the first aspect, the hydrodynamic bearing that further acts in the radial direction is provided, so that the tool shaft is stable without being shaken in the direction orthogonal to the axial direction of the main shaft. Tools can be inserted and removed and processed.

  According to the invention described in claim 3 or 4, since the fluid pressure acting on the fluid bearing can be adjusted, the optimum value of the pressure can be adjusted in accordance with the situation at the time of processing and insertion, and damage or The effect of preventing wear can be increased, and the processing accuracy can be further improved.

According to the fifth aspect of the present invention, the line boring bar takes the most suitable support form in each process, particularly in the processing process using a long line boring bar or in the process of inserting / removing the line boring bar into / from the bar support hole. Therefore, stable tool insertion and removal and high-precision machining are possible.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a spindle device for a machine tool embodying the invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of the spindle device of the present invention. A spindle 4 is rotatably supported in the housing 2 of the spindle head 1 of the machine tool via front and rear bearings 3. The main shaft 4 is driven and rotated by a motor (not shown) connected to the rear portion of the main shaft 4. A first main shaft flow path 5 and a second main shaft flow path 6 are formed in the main shaft 4. The first main shaft flow path 5 and the second main shaft flow path 6 are connected to a first inlet flow path 7 and a second inlet flow path 8 at the rear of the main shaft, respectively, via a rotary joint (not shown). The first inlet channel 7 and the second inlet channel 8 are connected to a fluid supply source 9.

  Next, the configuration of the line boring bar support when a line boring bar is attached as a processing tool will be described with reference to FIGS. 1 and 2. FIG. 2 is an enlarged sectional view around the line boring bar 10 and the holder 11. A flange 12 is fixed to the front end surface of the main shaft 4 with bolts 13. A hollow holder 11 is provided so as to surround the outer peripheral surface of the flange 12, and a support end of the line boring bar 10 is fixed to the front end surface of the holder 11 via a bolt 14. Further, a key groove 12a is provided in a part of the flange 12, and the main shaft 4 and the holder 11 can be rotated together by engaging with the protruding portion 11a of the holder 11, and the holder 11, the line boring bar 10, the main shaft 4 and A line boring bar 10 is supported in a floating manner with respect to the main shaft 4 through a bearing gap formed between the flange 12 and the shaft 12.

  A radial bearing 15 is provided on the outer peripheral surface in front of the main shaft 4 and is branched from the first main shaft flow path 5 and formed between the outer peripheral surface of the main shaft 4 and the inner peripheral surface of the holder 11. The inside of the flange 12 is formed with a front thrust bearing portion 16a formed between the front end surface of the flange 12 and the rear end surface of the line boring bar 10, and a rear thrust bearing portion 16b formed between the rear end surface of the flange 12 and the inner surface of the holder 11. Has been.

Next, the operation of the spindle device of the machine tool in this configuration will be described with reference to FIGS.
FIG. 3 is a cross-sectional view showing the periphery of the processing portion, and FIG. 4 is a cross-sectional view around the holder 11 showing a state in which the front end face of the flange 12 is in contact with the rear end face of the line boring bar 10. The workpiece W to be machined is fixed to a table (not shown), the support hole 18 of the support member 17 for supporting the line boring bar 10 being machined on both sides outside the workpiece W, and a plurality of journal parts to be machined in the workpiece W Arranged so that Wh is in a straight line. Thereafter, the line boring bar 10 is inserted into the support hole 18 of each support member 17 and the journal portion Wh of the workpiece W from the front end surface. Thereafter, rotation of the spindle 4 is started, and the journal portion Wh of the workpiece W is processed by a plurality of cutting tools 19 provided on the outer peripheral surface of the line boring bar 10 while cutting and feeding the line boring bar 10 by feed movement. It has become. The pressure fluid is supplied from the external fluid source through the fluid path 20 to the inner peripheral surface of the support hole 18 from the start of the insertion of the line boring bar 10. The line boring bar 10 is stably supported by this fluid pressure. After processing the workpiece W, the line boring bar 10 is pulled out from the support hole 18 and the journal portion Wh, and the processing is completed.

  In this series of operations, when the line boring bar 10 is inserted and withdrawn, the on-off valve 21 provided in the second inlet channel 8 is switched to the off state, and the supply of fluid supplied from the fluid supply source 9 is performed. Is cut off. At this time, since the fluid is continuously supplied to the first inlet channel 7, the fluid pressure of the front thrust bearing portion 16a stops and the fluid pressure of the rear thrust bearing portion 16b continues to act. Since the fluid pressure acts only on the rear thrust bearing portion 16b, the rear end surface of the line boring bar 10 is in contact with the front end surface of the flange 12 as shown in FIG. The line boring bar 10 can be fixed in a predetermined posture, and the axis of the line boring bar 10 is not inclined. Accordingly, the line boring bar 10 can be inserted straight into the support hole 18 and the journal portion Wh. During the processing of the workpiece W, the on-off valve 21 is switched to the on state, and the fluid is supplied from the fluid supply source 9. At this time, fluid pressure is applied to both the front thrust bearing portion 16a and the rear thrust bearing portion 16b, and the line boring bar 10 and the holder 11 are in a floating support state. When the line boring bar 10 and the holder 11 are floated, the axis of the line boring bar 10 is adjusted in accordance with the support force of the support member 17, and the hole machining accuracy is improved.

According to the spindle device of the machine tool of the above embodiment, the following effects can be obtained.
(1) In the above-described embodiment, when the line boring bar 10 is inserted and withdrawn, the on-off valve 21 provided in the second inlet channel 8 is switched to the off state, and the supply of the fluid supplied from the fluid supply source 9 is performed. As a result, the front end surface of the flange 12 and the rear end surface of the line boring bar 10 are in contact with each other, and the axis of the line boring bar 10 is not inclined. Accordingly, the line boring bar 10 can be inserted straight into the support hole 18 and the journal portion Wh. Therefore, the line boring bar 10 can be inserted and pulled out in a stable posture, and damage and wear of the line boring bar 10 and the support hole 18 can be eliminated.

(2) In the above embodiment, when the workpiece W is processed, the on-off valve 21 is switched on, and fluid pressure is applied to both the front thrust bearing portion 16a and the rear thrust bearing portion 16b. In the floating state, the axis of the line boring bar 10 is adjusted in accordance with the support force of the support member 17, so that the drilling accuracy can be improved.

In addition, you may change the said embodiment as follows.
As shown in FIG. 5, a radial bearing 15, a front thrust bearing portion 16 a and a rear thrust bearing portion 16 b are provided in a holder 23 attached to the front end portion of the main shaft 4 to support the support end of the line boring bar 10. A flange portion 22a is formed on the outer peripheral surface of the line boring bar holder 22 and a groove portion 22b is formed on the rear end surface. The line boring bar holder 22 is engaged with a key 24 fixed to the holder 23, and the line boring bar holder 22 is An embodiment that supports the holder 23 so as to be floatable may be adopted.
-Although the example which processes using a line boring bar as a tool provided with the floating mechanism was shown in the said embodiment, you may employ | adopt this invention for the other tool which employ | adopted the floating mechanism.

Sectional drawing which shows the whole structure of the main shaft apparatus of this invention. The expanded sectional view which shows the holder periphery of the main axis | shaft apparatus of this invention. Sectional drawing which shows the structure of the process part vicinity at the time of the line boring process in the machine tool provided with the spindle apparatus of this invention. Sectional drawing which shows arrangement | positioning at the time of interrupting | blocking the fluid pressure supply of a back thrust bearing part in the main axis | shaft apparatus of this invention. Sectional drawing of the spindle apparatus of the machine tool in another embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 4 ... Main shaft, 5 ... 1st main shaft flow path, 6 ... 2nd main shaft flow path, 7 ... 1st inlet flow path, 8 ... 2nd inlet flow path, 10 ... Line boring bar, 11 ... Holder, 11a ... Projection part, 12 ... flange, 12a ... keyway, 15 ... radial bearing, 16a ... front thrust bearing part, 16b ... rear thrust bearing part, 21 ... on-off valve, W ... work, Wh ... journal part.

Claims (5)

In a spindle device of a machine tool that supports a machining tool in a floating manner with respect to a spindle, a fluid supply flow path is provided inside the spindle, and a fluid pressure of a fluid supplied from the flow path acts on the fluid bearing. The support means for supporting the support end of the processing tool is provided via the support means, and the fluid bearing of the support means is a thrust bearing, and the thrust bearing acts on the processing tool in the axial direction forward of the main shaft. The front thrust bearing portion to be switched and the rear thrust bearing portion to apply fluid pressure to the axially rear side of the main shaft, and switching capable of shutting off the fluid pressure acting on either the front thrust bearing portion or the rear thrust bearing portion. A spindle device for a machine tool, characterized in that means is provided in the flow path. 2. The spindle device for a machine tool according to claim 1, wherein a radial pressure is applied to the machining tool in a direction perpendicular to the axial direction of the spindle on the one of the channels that does not have switching means. A spindle device for a machine tool, characterized in that a bearing is provided. 3. The spindle device for a machine tool according to claim 1, further comprising an adjusting mechanism capable of adjusting a fluid pressure of a fluid acting on the fluid bearing. 3. The spindle device for a machine tool according to claim 1, further comprising an adjusting mechanism capable of adjusting a fluid pressure of a fluid acting on the fluid bearing for each flow path. 2. A method for supporting a line boring bar as the machining tool on the spindle device of a machine tool according to claim 1, wherein the line to the line boring bar support hole spaced apart on the same axis as the spindle at a workpiece machining position. When the boring bar is inserted and removed, the fluid pressure is shut off by the switching means, and the line boring bar is fixedly supported to the main shaft. When machining a workpiece, the line boring bar is floated without shutting off the fluid pressure by the switching means. A line boring bar supporting method, characterized by supporting.

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