KR100658337B1 - A magnetic cylinder for the tool existence sensing and clamping of a mucining center - Google Patents

Abstract

The present invention relates to a tool presence sensing, clamping and unclamping device of a machining center spindle, and to forming a magnetic cylinder by a coil wound on a spindle body, and having a piston made of a nonmagnetic material and a magnetic body at the rear of the drawbar. The position change in the magnetic cylinder is detected by the difference in the magnetoresistance so that the presence or absence of the tool, clamping and unclamping can be detected.

Machining Center, Spindle, Tool, Magnetic, Detection

Description

Magnetic cylinder for the tool existence sensing and clamping of a mucining center

1 is an assembly cross-sectional view for detecting the presence of the tool in the conventional machining center spindle, clamping, unclamping

Figure 2 is a cross-sectional view of the main shaft equipped with the present invention magnetic cylinder

  a) is the state of tool unclamping

  b) tool clamping state diagram

  c) is the operating state without tools

3 is a conceptual view of operation of the present invention magnetic cylinder

4 is a graph relating to inductance and time constant of the present invention

※ Explanation of code for main part of drawing

101. Spindle Body 102. Magnetic Cylinder

103. Coil 104. Drawbar

105. Nonmagnetic Materials 106. Magnetic Materials

107. Spindle

The present invention relates to a tool clamping device of a machining center spindle, and more particularly, to a magnetic cylinder capable of detecting a tool presence and clamping with a simple structure without causing problems in the length and rotational balancing of the spindle.

The known tool clamping device of the machining center spindle has a holding device on the inner side of the tool. When the spindle is rotated in the absence of a tool, it is difficult to support the outside of the collet. A problem arises.

In addition, even if the tool is not clamped even if the outer diameter of the tool clamping collet is supported, the tool clamping device including the drawbar inside the spindle is not fixed. Can be.

Therefore, it is necessary to limit the rotation of the spindle by detecting the presence of tool mounting in the case of a spindle that rotates at high speed or in the case of a spindle using a tool with a tool holding device.

In order to detect whether the machining tool is installed in the conventional machining center, as shown in FIG. 1, the drawbar 2 is installed in the axial direction inside the spindle 1, and the drawbar 2 has a tool clamping spring 3 force. The restoring movement is possible by the axial direction, and the collet 5 for clamping the tool 4 is connected to the drawbar tip.

A cylinder body 7 and a cylinder piston 8 are provided in the rear main spindle body 6 of the draw bar to push the draw bar 2 in the axial direction, and the cylinder body 7 is provided with a grip 9. It is connected to the rear end side of the main shaft 1 by the media.

When there is no tool unclamping or no tool between the spindle body 6 and the cylinder body 7 by bufferingly restricting the cylinder body 7 from being retracted by the tool clamping spring 3 force on the spindle body 6. The predetermined relaxation gap L is generated.

That is, it is supported on the main shaft body 6 side to elastically press the cylinder body 7 with a constant force to function to induce the generation of the relaxation gap (L).

Therefore, when there is no tool in the collet 5, the tool clamping spring 3 force is greater than the pressing force of the shock absorbing spring 10, so that there is a constant relaxation interval L between the shear opposing surfaces of the cylinder body 7 and the spindle body 6. ) Is generated.

At this time, the presence or absence of the relaxation interval is configured to detect the cylinder position dog 11 and the tool presence detection switch 12 installed in the main shaft body 6 and the cylinder body (7).

In addition, the piston piston 8 is fixedly mounted with a piston position dog 13 which interlocks with the moving position of the draw bar 2, and the clamp and unclamped position of the piston position dog 13 is fixed to the cylinder body 7. A configuration in which the tool clamping detection sensor 14 and the tool unclamping detection sensor 15 to detect are installed has been proposed in the Patent Publication No. 10-2004-0059290.

However, since the tool clamping device as described above requires a separate sensor to check the existence of the tool, clamping, and unclamping, the main shaft needs to be longer than the length of the position dog to further configure the position dog and the sensor on the drawbar. There is a problem that the structure is complicated by the installation of a pneumatic cylinder, causing problems in the weakening of the main shaft and rotational balancing.

The present invention has been made to solve the above problems and can reduce the length of the main shaft and solve the cylinder and the sensing device that can detect the clamping and unclamping of the presence of the tool without causing problems in the rotation balancing at the same time An object of the present invention is to provide a magnetic cylinder.

The present invention for the above object 'magnetic cylinder for sensing and clamping the presence of the tool in the machining center spindle' winding the coil inside the body of the spindle to form an electromagnet and the drawbar is provided with a non-magnetic and magnetic material flowing in the coil Forces are generated in the direction of the main axis in proportion to the current, and in each case corresponding to clamping, unclamping, and the presence or absence of a tool, the nonmagnetic material has different positions of the piston and the magnetic material. The difference in the magnetoresistance according to the change of position makes the difference in inductance, and the difference in inductance is the rise time to the maximum current, that is, the time constant when the voltage is applied by changing the time constant. By determining the position of the clamp, it is possible to detect clamping, unclamping and the presence of a tool.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

For the well-known configuration before the detailed description, the description is omitted within the scope of not obscuring the configuration of the present invention to make the characteristic gist of the present invention more clear.

Figure 2 is an assembled cross-sectional view of the main shaft equipped with the magnetic cylinder of the present invention, a) is a tool unclamping state diagram, b) is a tool clamping state diagram, c) is an operating state diagram without a tool.

3 is a conceptual view illustrating the operation of the magnetic cylinder of the present invention, and FIG. 4 is a graph relating to inductance and time constant of the present invention.

The present invention is the same as the known conventional configuration except for the configuration related to the piston composed of the magnetic cylinder and the magnetic and nonmagnetic materials.

As shown in the drawing, the coil 103 forming the magnetic cylinder 102 is wound inside the main shaft body 101, and a nonmagnetic material is formed at an extended end of the draw bar 104 inside the coil 103. The 105 and the magnetic body 106 are integrated to form a piston.

When a current is applied to the coil 103 wound inside the main shaft body 101, a force is applied to the magnetic body 106 in the axial direction so that the piston in which the nonmagnetic 105 and the magnetic body 106 are integrated is the main shaft 107. Go to the rear of the.

If you describe this as a formula,

여기서 L은 인덕턴스, N은 권선의 수, Rm은 자기저항....(1)

Where L is the inductance, N is the number of windings, and Rm is the magnetoresistance .... (1)

여기서 W는 에너지,

는 권선에 흐르는 전류.........(2)

Where W is energy,

Is the current flowing in the winding ......... (2)

여기서

는

방향으로의 힘 ..................(3)과 같이 나타낼 수 있다.

here

Is

The force in the direction can be expressed as (3).

The change of the magnetoresistance due to the position of the piston causes the change of the inductance, and the displacement of the inductance can be used to check the displacement of the piston and the presence or absence of the tool, clamping and unclamping.

Since the main body body 101, which is a magnetic cylinder 102 having a structure separate from the draw bar 104, detects the presence of a tool, there is no fundamental problem in the rigidity or rotational balancing of the main shaft 107. .

The method of detecting the clamping, unclamping, and tool presence in the magnetic cylinder 107 has different positions of the piston depending on the clamping, unclamping, and tool presence. Thus, the position of the magnetic body 106 is also different in each case. Has a different position relative to

Therefore, since the magnetic resistance on the magnetic path according to the position of the magnetic body 106 is different for each position, the difference in the magnetic resistance makes the difference in inductance. Change.

When the voltage is applied, the position of each piston can be determined by obtaining the time constant, so that clamping, unclamping, and the presence of a tool can be detected.

The method of determining the time constant detects the current using the distribution (shunt) resistance, but the resistance of the winding is constant so that the time of arrival up to 66.6% of the expected maximum current is measured.

As described above, the present invention can solve the problem of rotational balancing of the spindle by simultaneously detecting the presence of the tool and clamping and unclamping of the tool without extending the length of the machining center spindle by using a magnetic cylinder of a simple configuration. There is an effect that can be produced at a low cost without causing.

Claims (1)

Built into the main shaft of the spindle body, the tip is connected to the collet and has a drawbar supported by the tool clamping spring, and detects the position of the drawbar moved in the axial direction by the operation direction of the cylinder body side piston installed at the rear of the drawbar, The coil 103 is wound inside the spindle body 101, and the drawbar is provided with a piston made of a nonmagnetic material 105 and a magnetic material 106 to form a magnetic cylinder 102, the presence or absence of a tool, clamping, For each case corresponding to unclamping, the difference of the magnetic resistance according to the position change of the piston is used to make the difference in inductance, and the time constant is determined by the difference in inductance. In a device for detecting a state, Magnetic cylinder for detecting and clamping the tool presence of the machining center spindle, characterized in that the force is generated in the direction of the main shaft (107) in proportion to the current flowing in the coil.

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