CN113635011A

CN113635011A - Vertical knife mounting machine

Info

Publication number: CN113635011A
Application number: CN202110925557.6A
Authority: CN
Inventors: 李国胜; 邹文毅; 杨超; 肖超群
Original assignee: Hunan Zdcy Cnc Equipment Co ltd
Current assignee: Hunan Zdcy Cnc Equipment Co ltd
Priority date: 2021-08-12
Filing date: 2021-08-12
Publication date: 2021-11-12

Abstract

The invention discloses a vertical tool setting machine, which is used for correcting a cutting tool of a spiral bevel gear, and comprises a stand column arranged on a machine body, a workpiece main shaft and a three-dimensional measuring head arranged on the stand column, wherein the three-dimensional measuring head is displaced along a Z axis relative to the stand column through a first sliding assembly, and the stand column is displaced along a Y axis relative to the machine body through a second sliding assembly; the rotating shaft of the workpiece main shaft is parallel to the Z axis; the measuring rod of the three-dimensional measuring head extends out of the body of the three-dimensional measuring head, and a height measuring needle and a radial measuring needle are arranged on the measuring rod, the height measuring needle is used for detecting the height position of the tool tip of the cutting tool to be detected, and the radial measuring needle is used for detecting the radial position of the cutting edge of the cutting tool to be detected; and a cutter pressing device is fixedly arranged on the body of the three-dimensional measuring head and is provided with a cutter pressing part, and the cutter pressing part can press and support the cutter point of the cutting tool to be measured along the Z axis. The scheme can effectively improve the adjustment precision through structural optimization and improve the operation efficiency.

Description

Vertical knife mounting machine

Technical Field

The invention relates to the technical field of machining, in particular to a vertical tool mounting machine for correcting a spiral bevel gear cutting tool.

Background

In the prior art, a horizontal adjusting method for adjusting a cutting tool of a spiral bevel gear is limited by the principle of the horizontal adjusting method, and the problem of low tool mounting efficiency exists. Meanwhile, the rear cutter face of the strip-shaped cutter bar cutting edge is detected and adjusted by the method, in practical application, based on abrasion of a grinding wheel of the knife sharpener, the change of the rear cutter face is large, the part participating in cutting is the cutting edge, and certain adjustment errors exist in the measured rear cutter face, so that the number of processed workpieces is small, and the use efficiency is low.

In view of the above, it is desirable to optimize the design of the correction device for the cutting tool of the spiral bevel gear to overcome the above technical drawbacks.

Disclosure of Invention

In order to solve the technical problem, the invention provides a vertical type cutter mounting machine, which aims to effectively improve the operation efficiency through structural optimization.

The invention provides a vertical tool mounting machine, which is used for correcting a cutting tool of a spiral bevel gear, and comprises a stand column arranged on a machine body, a workpiece main shaft and a three-dimensional measuring head arranged on the stand column, wherein the three-dimensional measuring head is displaced along a Z axis relative to the stand column through a first sliding assembly, and the stand column is displaced along a Y axis relative to the machine body through a second sliding assembly; the rotating shaft of the workpiece main shaft is parallel to the Z axis; the measuring rod of the three-dimensional measuring head extends out of the body of the three-dimensional measuring head, and a height measuring needle and a radial measuring needle are arranged on the measuring rod, the height measuring needle is used for detecting the height position of the tool tip of the cutting tool to be detected, and the radial measuring needle is used for detecting the radial position of the cutting edge of the cutting tool to be detected; and a cutter pressing device is fixedly arranged on the body of the three-dimensional measuring head and is provided with a cutter pressing part, and the cutter pressing part can press and support the cutter point of the cutting tool to be measured along the Z axis.

Preferably, the radial stylus is located close to the overhanging end side of the measuring rod with respect to the height stylus.

Preferably, the measuring part of the height measuring probe can extend and contract along the Z axis relative to the height measuring probe body.

Preferably, the measuring part of the radial measuring probe can be extended and retracted along the Z axis and the Y axis relative to the radial measuring probe body, and the measuring part of the radial measuring probe is a sphere or a hemisphere.

Preferably, the cutter pressing device comprises a fixing rod and a cutter pressing rod, the fixing rod is fixedly connected with the body of the three-dimensional measuring head, the cutter pressing part is formed on the cutter pressing rod, the cutter pressing rod is connected with the fixing rod, and the position of the cutter pressing rod relative to the fixing rod along the Z axis is adjustable.

Preferably, the pressing tool bar is located below the fixing rod, one end of the pressing tool bar is fixedly connected with the fixing rod, and the other end of the pressing tool bar is connected with the fixing rod through an adjusting piece so as to adjust the position of the other end of the pressing tool bar relative to the fixing rod along the Z axis; the pressing cutter part is positioned at the other end of the pressing cutter rod.

Preferably, the adjusting member is a bolt; one of the pressing cutter rod and the fixed rod is provided with a threaded hole matched with the bolt, and the other pressing cutter rod is provided with a pressing surface opposite to the threaded hole.

Preferably, the cutter pressing part is provided with a through hole, and the measuring part of the height measuring pin can be inserted into the through hole.

Preferably, the first sliding assembly comprises a Z-axis guide rail and a Z-axis sliding block which are matched, and the second sliding assembly comprises a Y-axis guide rail and a Y-axis sliding block which are matched.

Preferably, the Z-axis slider is driven by a Z-axis motor to displace relative to the Z-axis guide rail, and the Y-axis slider is driven by a Y-axis motor to displace relative to the Y-axis guide rail; a Z-axis sensor is arranged on the upright column to detect the displacement of the Z-axis slide block; and a Y-axis sensor is arranged on the Z-axis sliding block to detect the displacement of the Y-axis sliding block.

Aiming at the cutting tool of the spiral bevel gear, a vertical tool mounting machine is proposed in another method. Specifically, adjustment and control of the error of the tool bars of the tool to be measured are achieved through the three-dimensional measuring head, and the three-dimensional measuring head can move along the Y axis and the Z axis relative to the lathe bed so as to adjust the working position of the three-dimensional measuring head according to the actual sizes of different tools to be measured. The measuring rod extending out of the three-dimensional measuring head body is provided with a height measuring needle and a radial measuring needle, the height measuring needle is used for detecting the height position of a tool nose of a cutting tool to be measured so as to control the axial error of the tool section, and the radial measuring needle is used for detecting the radial position of a cutting edge of the cutting tool to be measured so as to adjust the radial runout error of the tool section; meanwhile, a cutter pressing device is fixedly arranged on the body of the three-dimensional measuring head, and a cutter pressing part of the cutter pressing device can press and abut against the cutter point of the cutting tool to be measured along the Z axis so as to quickly realize the positioning of each cutter strip in the height direction. Compared with the prior art, the invention has the following beneficial technical effects:

firstly, the vertical tool mounting machine provided by the invention is convenient for the integral hoisting operation of the tool, and can effectively improve the mounting efficiency compared with a horizontal machine tool; meanwhile, the scheme does not need a tailstock center of the workpiece shaft and other systems, the shaft system is reduced, the equipment cost is reduced, and on the basis, the characteristics of good rigidity of the installation shaft system and high adjustment precision are achieved.

Secondly, when this scheme of application carries out the timing operation, the knife tip that can utilize the pressure sword portion of pressing the sword device to press and support and act on the sword strip, with each sword strip automatic positioning of the cutter that awaits measuring at design height, on this basis, carries out the radial position timing of each sword strip again, has improved timing efficiency.

Thirdly, in a preferred embodiment of the present invention, the measuring part of the height measuring probe can extend and contract along the Z axis relative to the height measuring probe body, and the measuring part of the radial measuring probe can also extend and contract along the Z axis and the Y axis relative to the radial measuring probe body, so that the working heights of the corresponding measuring parts can be adjusted as required during the adjustment process, so as to perform corresponding position detection on a plurality of cutter bars circumferentially arranged on the cutter head one by one, thereby satisfying the functional requirement of rapid adjustment; in addition, the tool setting device can be widely applied to adjustment of different tool types.

Fourthly, in another preferred embodiment of the present invention, the fixing rod of the cutter pressing device is fixedly connected to the body of the three-dimensional measuring head, the cutter pressing bar thereof is connected to the fixing rod, and the position of the cutter pressing bar relative to the fixing rod along the Z axis is adjustable, so that the height position of the cutter pressing portion formed on the cutter pressing bar has an adjustable function; that is, the base height position of the knife pressing portion can be set according to the specific knife size, thereby further improving the applicability of the vertical knife loader.

Drawings

FIG. 1 is a schematic view of the overall structure of a vertical knife loader according to an embodiment;

FIG. 2 is an enlarged view of a portion of a measuring end of the three-dimensional probe shown in FIG. 1;

FIG. 3 is a schematic diagram illustrating dimensional relationships of the adjustment of the cutter head in an embodiment;

FIG. 4 is a schematic view of the radial stylus touching the edge measurement point of the inner blade bar;

FIG. 5 is a schematic view of the radial side needle touching the edge measurement point of the outer blade bar;

fig. 6 is an enlarged view of a portion a of fig. 1.

In the figure:

the device comprises a lathe bed 1, a workpiece spindle 2, a column 3, a three-dimensional measuring head 4, a measuring rod 41, a body 42, a height measuring pin 43, a measuring part 431, a radial measuring pin 44, a measuring part 441, a Z-axis guide rail 51, a Z-axis slide block 52, a Z-axis grating ruler 53, a Z-axis motor 54, a Y-axis guide rail 61, a Y-axis slide block 62, a Y-axis grating ruler 63, a Y-axis motor 64, a knife pressing device 7, a fixed rod 71, a threaded hole 711, a knife pressing rod 72, a knife pressing part 721, a pressing surface 722, a passing hole 723, a bolt 73 and a balancing device 8;

the cutter head 9, an outer cutter strip 91, an inner cutter strip 92, a threaded fastener 93 and a cutter groove 94.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

Please refer to fig. 1, which is a schematic view of the overall structure of the vertical tool changer according to the present embodiment.

The vertical tool mounting machine is used for correcting a cutting tool of a spiral bevel gear, and as shown in the figure, a machine body 1 is used as a machine tool foundation and is provided with a workpiece main shaft 2 and a stand column 3. The workpiece spindle 2 can rotate along the direction indicated by the arrow C to construct a single installation shaft system, and the center line of the rotation shaft is parallel to the Z axis; the cutter head 9 of the tool to be measured can be mounted on the workpiece spindle 2 and rotates together with the workpiece spindle 2 about its axis of rotation. In this embodiment, other main functional components are provided on the column 3.

The three-dimensional measuring head 4 moves relative to the lathe bed 1 along a Y axis and a Z axis through two groups of sliding components; here, the "Y axis" and the "Z axis" constitute two dimensions forming a calibration coordinate system, and as indicated by arrows in the drawing, the "Y axis" defines a left-right displacement direction, and the "Z axis" defines a vertical displacement direction, and it should be understood that the above dimensions are defined for clearly describing a dynamic fit relationship between associated members, and do not constitute a substantial limitation to the vertical tool changer claimed in the present application.

The three-dimensional measuring head 4 is displaced along the Z axis relative to the column 3 by a first sliding assembly, specifically, the first sliding assembly comprises a Z axis guide rail 51 and a Z axis slide block 52 which are matched, wherein the Z axis guide rail 51 is arranged on the column 3, and the three-dimensional measuring head 4 is arranged on the Z axis slide block 52. The column 3 is displaced along the Y axis relative to the bed 1 by a second sliding assembly, specifically, the second sliding assembly includes a Y-axis guide rail 61 and a Y-axis slider 62 which are matched, as shown in fig. 1, the Y-axis guide rail 61 is arranged on the bed 1, the Y-axis slider 62 is located at the bottom of the column 3, and the two are fixed together.

In the scheme, the three-dimensional measuring head 4 can simultaneously sense the three-dimensional coordinate change of the measured point, and the detection precision is high. It can be understood that the working mechanism of the three-dimensional measuring head 4 is not the core invention point of the present application, and can be realized by those skilled in the art based on the prior art, so that the details are not described herein.

Referring to fig. 2, a partially enlarged view of the measuring end of the three-dimensional probe 4 shown in fig. 1 is shown. The measuring rod 41 of the three-dimensional measuring head 4 extends out of the body 42 thereof to drive the height measuring needle 43 and the radial measuring needle 44 thereon to displace according to actual calibration requirements. Wherein, the height measuring needle 43 is used for detecting the height position of the tool tip of each tool section (91, 92) on the cutter head 9 of the cutting tool to be detected so as to control the axial error of the tool section; the radial measuring needle 44 is used for detecting the radial position of the cutting edge of each cutter strip (91, 92) on the cutter disc 9 so as to adjust the radial run-out error of the cutter strips. Based on this arrangement, the radial and height consistency of the bars (91, 92) on the cutterhead 9 of the cutting tool to be measured is determined. Referring to fig. 3, a schematic diagram of the dimensional relationship of the adjustment of the cutter head is shown.

It should be noted that the cutting tool of the spiral bevel gear includes two sets of tool bars: the outer blade bars 91 and the inner blade bars 92 are, as shown in fig. 1, sequentially arranged along the circumferential direction at intervals, respectively, and the outer blade bars 91 and the inner blade bars 92 are sequentially arranged along the circumferential direction at intervals. For simplicity of illustration, the radial and height dimension relationships of the various bars are illustrated in FIG. 3 by the inner bar 92. Each blade is inserted into a corresponding blade groove of the cutter head 5 and is positioned and fixed through a threaded fastener 93.

In this embodiment, the blade pressing device 7 is fixedly provided on the body 42 of the three-dimensional probe 4, and the blade pressing device 7 can move along the Y axis and the Z axis in synchronization with the three-dimensional probe 4 based on the sliding component. The cutter pressing device 7 has a cutter pressing portion 721 through which the tip of each blade of the cutting tool to be measured can be pressed along the Z-axis.

The following briefly describes the specific operation flow of the vertical knife loader applying the scheme:

firstly, preassembling a cutter strip.

Firstly, respectively pre-installing an inner cutter strip 92 and an outer cutter strip 91 into a cutter groove 94 according to a designed position, and screwing an upper threaded fastener 93 and a lower threaded fastener 93 on the side surface of a cutter head 9; then the blades rotate for a certain angle respectively, and the blades can freely slide in the corresponding cutter grooves without falling. An operator can push each cutter bar by hand to check whether the cutter bars can be pushed easily, and finally, each cutter bar is pulled up to about 5-10mm above the set height for installing the cutter.

And secondly, adjusting and preparing the cutter head.

And (3) installing the cutter head 9 pre-installed with the cutter strip on the workpiece spindle 2, inputting the parameters of the cutter head and the cutter strip into a machine tool, and establishing a cutter head adjustment model. Then, the Y axis and the Z axis are manually moved, and the blade tip of the reference blade (outer blade or inner blade) is pressed by the blade pressing portion 721 of the blade pressing device 7, as shown in fig. 2, and the reference blade is moved down to a predetermined position along the blade groove, and preferably, the EZ direction reading of the three-dimensional probe 4 is controlled to be about 0.4 mm. The system records the position data of each axial pressing cutter at the moment and takes the position data as an adjusting reference value.

And thirdly, starting a system adjusting program.

Firstly, a cutter installing procedure is started, and according to the cutter disc adjusting model and the set cutter pressing position, the inner cutter strip and the outer cutter strip are automatically pressed to the cutter installing set height in sequence, as shown in fig. 2. And after the Y-axis errors of all the cutter bars are within the tolerance range of the specified height, sequentially screwing the upper and lower threaded fasteners 93 according to the rated torque requirement. Then, a blade measurement procedure is started, and radial errors of the blade measurement points of the inner and outer blades are sequentially measured by using the radial measuring pins 44 in a Y-axis and C-axis linkage manner, please refer to fig. 4 and 5 together, where fig. 4 is a schematic diagram of the blade measurement point where the radial measuring pin 44 touches the inner blade 92, and fig. 5 is a schematic diagram of the blade measurement point where the radial side pin 44 touches the outer blade 91.

In the measuring process of the radial error, the cutter bar beyond the radial error range can be adjusted in height and in a screw tightening torque mode, so that the radial error of the cutter bar is within a set tolerance range. Of course, the tool bars still cannot be adjusted to the set tolerance range through comprehensive adjustment, and need to be replaced and then correspondingly adjusted until the tool bars are adjusted to the set tolerance range. Compare in the timing mode of detecting bar sword strip cutting edge back knife face, this scheme can effectively reduce the timing error, and the quantity of the workable work piece of cutter can promote simultaneously after the timing.

In order to reduce the influence of the knife pressing device on the radial error measurement operation space, the radial stylus 44 is preferably located close to the protruding end side of the measuring rod 41 with respect to the height stylus 43. That is, the radial direction probe 44 is positioned on the side of the extended end of the measuring rod 41, and the height probe 43 is positioned on the side of the measuring rod 41 closer to the main body 42, so that the space for measuring the radial direction error can be avoided after the pressing operation is completed.

In this embodiment, the measurement portion 431 of the height gauge 43 is extendable and retractable along the Z axis with respect to the body of the height gauge 43, and similarly, the measurement portion 441 of the radial gauge 44 is extendable and retractable along the Z axis and the Y axis with respect to the body of the radial gauge 44, and is adapted to the tool detection requirement by the posture change. Therefore, the working height of the corresponding measuring part can be adjusted according to the requirement in the adjusting process, so that the corresponding position detection can be carried out on the cutter strips which are circumferentially arranged on the cutter head one by one, and the functional requirement of quick adjustment is met; in addition, the method can be widely applied to adjustment of types of tools.

Preferably, the measuring portion 441 of the radial stylus 44 may be a sphere or a hemisphere, and may be in point contact with the blade measuring point, thereby improving the detection accuracy.

Further, in order to improve the applicability of the vertical type knife loader, the structure of the knife pressing device 7 can be optimized. As shown in fig. 2, the blade pressing device 7 includes a fixing rod 71 and a blade pressing rod 72, wherein the fixing rod 71 is fixedly connected to the body 42 of the three-dimensional measuring head 4, and a blade pressing portion 721 for pressing the blade tip is formed on the blade pressing rod 72. In this embodiment, the pressing bar 72 of the pressing device 7 is connected to the fixing rod 71, and the position of the pressing bar 72 relative to the fixing rod 71 along the Z axis is adjustable. Thus, the height position of the press blade portion 721 formed on the press blade bar 72 has an adjustable function; that is, the base height position of the blade pressing portion 721 can be set according to a specific tool size.

It will be appreciated that the above-described position adjustable function can be implemented in different ways. Such as, but not limited to, the preferred example structures shown in the figures. As shown in the figure, the pressing bar 72 is located below the fixing rod 71, and one end of the pressing bar 72 is fixedly connected with the fixing rod 71, and the other end is connected with the fixing rod 71 through an adjusting piece (73) so as to adjust the position of the other end of the pressing bar 72 relative to the fixing rod 71 along the Z axis; here, the pressing blade part 721 is located at the other end of the pressing blade bar 72, in other words, the one-side end of the pressing blade bar 72 is height-adjustable, and the material selection is specifically performed according to the actual adjustment range, and it is within the scope of the claimed application as long as the functional requirements of the one-side end height adjustment are met.

Specifically, the adjusting member is a bolt 73, a threaded hole 711 adapted to the bolt is formed in the fixing rod 71, so that the bolt 73 can be rotated as required to adjust the length of the rod end, and accordingly, the pressing bar 72 has a pressing surface 722 opposite to the threaded hole 711. The bolt 73 is rotated to push the cutter bar 72 to change the relative position between the cutter bar and the fixed rod 71. Has the characteristics of simple and reliable structure and convenient operation.

Of course, in order to further improve the structural integration, the knife pressing portion 721 may be formed with a through hole 723, and the measuring portion 431 of the height measuring pin 43 may be inserted into the through hole 723. Please refer to fig. 1 and fig. 6 together, wherein fig. 6 is an enlarged view of a portion a of fig. 1. Thus, the measuring portion 431 of the height gauge 43 can perform its height detecting function through the passing opening 723, and at the same time, the blade pressing portion 721 having the passing opening 723 can maintain its function of pressing against the blade tip.

In this embodiment, the Z-axis slider 52 is driven by a Z-axis motor 54 to displace with respect to the Z-axis guide 51, and the Y-axis slider 62 is driven by a Y-axis motor 64 to displace with respect to the Y-axis guide 61; here, the Z-axis motor 54 and the Y-axis motor 64 are both linear motors.

In addition, a Z-axis sensor (53) is arranged on the upright post 3 to detect the displacement of the Z-axis slide block 52, so that a closed-loop control system can be formed together with a Z-axis motor 54 for providing power; a Y-axis sensor (63) is provided on the Z-axis slider 52 to detect the amount of displacement of the Y-axis slider 62, thereby forming a closed-loop control system with a powered Y-axis motor 64. So set up, can full-automatic realization measurement cycle, realize its precision measurement function through high accuracy scanning gauge head to rely on positioner of high accuracy, realize the timing function of sword strip installation accuracy. Preferably, the Z-axis sensor may employ a Z-axis grating scale 53, and the Y-axis sensor may employ a Y-axis grating scale 63.

In addition, in order to make the up-and-down movement along the Z axis more stable, a balance device 8 may be added to balance the weight of the Z axis slider 52, the Y axis guide 51, and the like.

It should be noted that, in the above embodiments provided in this embodiment, functions such as the motor and the grating ruler constitute non-core points of the invention of this application, and those skilled in the art can implement the functions based on the prior art, so details are not described herein again.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.

Claims

1. A vertical tool setting machine is used for correcting a cutting tool of a spiral bevel gear and is characterized by comprising a stand column and a workpiece main shaft which are arranged on a machine body, and further comprising a three-dimensional measuring head arranged on the stand column, wherein the three-dimensional measuring head is displaced along a Z axis relative to the stand column through a first sliding assembly, and the stand column is displaced along a Y axis relative to the machine body through a second sliding assembly; the rotating shaft of the workpiece main shaft is parallel to the Z axis;

the measuring rod of the three-dimensional measuring head extends out of the body of the three-dimensional measuring head, and a height measuring needle and a radial measuring needle are arranged on the measuring rod, the height measuring needle is used for detecting the height position of the tool tip of the cutting tool to be detected, and the radial measuring needle is used for detecting the radial position of the cutting edge of the cutting tool to be detected;

and a cutter pressing device is fixedly arranged on the body of the three-dimensional measuring head and is provided with a cutter pressing part, and the cutter pressing part can press and support the cutter point of the cutting tool to be measured along the Z axis.

2. The vertical tool setting machine of claim 1, wherein the radial stylus is located proximate to an overhanging end side of the measuring stick relative to the height stylus.

3. The vertical tool setting machine of claim 1, wherein the measuring portion of the height stylus is extendable and retractable along the Z-axis relative to the height stylus body.

4. The vertical tool setting machine of claim 1, wherein the measuring portion of the radial stylus is retractable relative to the radial stylus body along the Z-axis and the Y-axis, and the measuring portion of the radial stylus is a sphere or a hemisphere.

5. The vertical tool setting machine of claim 1, wherein the tool pressing device comprises a fixing rod and a tool pressing bar, the fixing rod is fixedly connected with the body of the three-dimensional measuring head, the tool pressing portion is formed on the tool pressing bar, the tool pressing bar is connected with the fixing rod, and the position of the tool pressing bar along the Z axis relative to the fixing rod is adjustable.

6. The vertical type knife loader according to claim 5, characterized in that the presser bar is located below the fixed rod, and one end of the presser bar is fixedly connected with the fixed rod, and the other end of the presser bar is connected with the fixed rod through an adjusting member, so as to adjust the position of the other end of the presser bar relative to the fixed rod along the Z axis; the pressing cutter part is positioned at the other end of the pressing cutter rod.

7. The vertical tool setting machine of claim 6, wherein the adjustment member is a bolt; one of the pressing cutter rod and the fixed rod is provided with a threaded hole matched with the bolt, and the other pressing cutter rod is provided with a pressing surface opposite to the threaded hole.

8. The vertical type knife loader according to any one of claims 5 to 7, characterized in that the knife pressing part is provided with a through opening, and the measuring part of the height measuring pin can be inserted into the through opening.

9. The vertical knife loader of claim 1 wherein the first slide assembly comprises mating Z-axis guides and Z-axis slides and the second slide assembly comprises mating Y-axis guides and Y-axis slides.

10. The vertical tool setting machine of claim 9, wherein the Z-axis slide is displaced relative to the Z-axis guide by a Z-axis motor and the Y-axis slide is displaced relative to the Y-axis guide by a Y-axis motor; a Z-axis sensor is arranged on the upright column to detect the displacement of the Z-axis slide block; and a Y-axis sensor is arranged on the Z-axis sliding block to detect the displacement of the Y-axis sliding block.