JP2004209587A - Electrode fixing jig for internal grinding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode fixing jig for carrying out an electrolytic dressing method regarding an internal grinding machine using a metal bond grinding wheel. <P>SOLUTION: The electrode fixing fixture 1 is constituted of an electrode 10 having an approximately L shape; an electrode support member 11 for fixing/supporting the electrode 10; an adjustment means 12 for supporting the electrode support member 11; and a base member 13 for supporting the adjustment means and fixing the whole of the fixture to a spindle. The material of the electrode may include the material having conductivity, and copper, brass, stainless steel or the like are particularly preferable as the material. For the support member 11 for supporting the electrode, an insulation body, for example, a synthetic resin such as bulky nylon and polypropylene is preferable. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a jig for mounting electrodes required when applying a technique of grinding a workpiece to be processed while electrolytically dressing a metal bond grindstone to an inner surface grinding device.
[0002]
[Prior art]
Metal-bonded grindstones made by combining superabrasive grains such as diamond and cubic boron nitride (cBN) with a metal such as cast iron as a binder are used for grinding hard materials such as ceramics and cemented carbide, and brittle materials such as glass. It is known as a grindstone capable of efficient processing. This metal-bonded grindstone requires regular grinding work (dressing) because grinding performance decreases due to wear, which is a so-called blind type, as grinding progresses. In such a case, since the grinding operation needs to be stopped once, the grinding operation may be inefficient.
[0003]
Therefore, a technique described in Patent Literature 1 has been proposed as a grinding technique (grinding apparatus) for performing this dressing during a grinding operation and preventing a decrease in efficiency. In this grinding technique, a weakly conductive grinding fluid is supplied to the grindstone and a pulse current is applied from an electrode installed outside using the grindstone as an anode, thereby dissolving the conductive metal (bonding material). On the other hand, the non-conductive abrasive grains remain and protrude, so that the abrasive grains are restored to a grindable state. By applying such a current constantly during the grinding process, the process can be performed efficiently without interrupting the work (hereinafter, such a method is referred to as an electrolytic dressing method).
[0004]
This electrolytic dressing method has an advantage that high-efficiency grinding can be performed by omitting an intermediate step of dressing, and that there is an advantage that damage to a material to be processed is small and high-precision grinding is possible. A grinding apparatus using this method has already been put to practical use.
[0005]
[Patent Document 1] Japanese Patent Publication No. 6-75823
[Problems to be solved by the invention]
By the way, the grinding apparatus to which the electrolytic dressing method is applied has been mainly for surface grinding. On the other hand, the use of the grinding process is not limited to surface grinding, and is often applied to curved surface grinding. However, there has been no example of applying the electrolytic dressing method to internal grinding.
[0007]
The present invention has been made under the above background, and has as its object to provide a method for applying the electrolytic dressing method to curved surface grinding, particularly to inner surface grinding.
[0008]
[Means for Solving the Problems]
In order to solve this problem, the present inventors first decided to use a general internal grinding device as a basic configuration of the grinding device. This is because the possibility of utilizing the electrolytic dressing method is increased by utilizing a general device. Here, as a general internal grinding device, for example, there is one as shown in FIG. The inner surface grinding apparatus shown in FIG. 5 includes a rotating shaft 101 on which a grindstone 100 is mounted, and a spindle 102 for rotating the rotating shaft 101. The spindle 102 is supported by a grindstone table 103, and the grindstone table 103 is mounted on a saddle 104 that can move forward, backward, left, and right. On the other hand, the workpiece W is held by the chuck 105 and is rotatable together with the chuck. In the grinding process, the grindstone 100 is rotated by the rotating shaft 102 while being brought into contact with the inner surface of the rotating work W, and further ground while being reciprocated in the work W.
[0009]
In order to enable electrolytic dressing for the internal grinding device having such a configuration, it is essential to first provide electrodes from the configuration of this method. In order to supply a stable electric power, it is necessary that the electrode can keep a constant distance from the grindstone. Therefore, the present inventors have decided to give a function of electrolytic dressing to a general inner surface grinding device by using a jig capable of fixing and adjusting the position of the electrode, and have developed a jig capable of this.
[0010]
The present invention is an electrode fixing jig that can be attached to an internal grinding device including a metal bond grinding wheel, a rotating shaft for attaching the grinding wheel, and a spindle for rotating the rotating shaft, and a power supply parallel to the grinding wheel and the rotating shaft. A substantially L-shaped electrode comprising a portion and a fixing portion perpendicularly intersecting with the power supply portion, an electrode supporting member for fixing the fixing portion of the electrode and supporting the electrode, and a grindstone for supporting the electrode supporting member and supporting the electrode. An electrode fixing jig for an internal grinding device, comprising: an adjusting means capable of adjusting a distance between the electrode and a base member supporting the adjusting means and fixed to the spindle.
[0011]
In this jig, the support member supporting the electrode is preferably an insulator. Although the constituent material of the electrode fixing jig according to the present invention is not particularly limited, a metal is often applied from the viewpoint of strength as long as it is a constituent member of a processing machine. On the other hand, when the electrode, the electrode support member, and the base member and all members are made of metal, the electrode is electrically short-circuited with the grindstone through the base member and the spindle. The members were insulated.
[0012]
Further, in the present invention, as the adjusting means for adjusting the distance between the electrode and the grindstone, a means that can finely adjust the distance between the electrode and the grindstone and that does not easily shake once fixed is preferable. As a configuration of such an adjusting unit, a moving unit that supports the electrode supporting member, and a fixed member that is fixed to the base member and supports the moving member while guiding the moving member, the moving unit includes a moving unit and There is a type that includes a dial that can be moved by an elastic body sandwiched between the fixing member and can be fixed in position by a screw that penetrates the fixing member from the moving unit, and that is interlocked with the screw.
[0013]
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to fix an electrode to a general internal grinding device, and it becomes possible to apply the electrolytic dressing which had only been applied to surface grinding until now to internal grinding. This makes it possible to efficiently perform the internal grinding, particularly the internal grinding of a hard material such as ceramics and cemented carbide, or a brittle material such as glass.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 shows the appearance of an electrode fixing jig for an internal grinding device according to the present embodiment. In FIG. 1, an electrode fixing jig 1 supports a substantially L-shaped electrode 10, an electrode supporting member 11 for fixing and supporting the electrode 10, an adjusting unit 12 for supporting the electrode supporting member 11, and an adjusting unit. And a base member 13 for fixing the entire jig to the spindle. The electrode 10 has one leg serving as a power supply unit parallel to the grindstone and the rotation axis, and a surface on the grindstone side at the tip thereof is formed with an R in accordance with the shape (cylindrical shape) of the grindstone. . The other leg serving as a fixing portion of the electrode is fixed to the electrode support member 11 together with the current supply cable 14 by a bolt 15. The electrode may be made of any material as long as it has conductivity, but copper, brass, stainless steel and the like are particularly preferable.
[0016]
The electrode support member 11 is formed of massive nylon which is an insulating material, and insulates the electrode from the adjusting means 12 and the base member 13. As the material of the electrode supporting member, synthetic resin such as polypropylene is preferable in addition to lump nylon, but synthetic resin having low tracking resistance such as vinyl chloride and phenol resin and wood insulating material having hygroscopicity are not so preferable. The size and shape of the electrode support member 11 are not particularly limited, but are preferably large enough to secure a contact area with the other leg of the electrode so that the electrode can be fixed without blurring.
[0017]
FIG. 2 shows the structure of the adjusting means 12. The adjusting unit 12 includes a moving unit 17 that supports the electrode supporting member 11 and a fixed member 18 that guides the moving unit 17 to move in a direction perpendicular to the axial direction. The fixing member 18 is fixed by being joined to the base member 13, and the moving portion 17 is fixed by a screw 19 and a dial 21 installed on the base member 13. At this time, a spring 20 is fitted between the fixed part 18 and the moving part 17, and the moving part 17 can be moved (in a direction to separate the electrode from the grindstone) by the repulsive force.
[0018]
And the base member 13 which supports the component member of a jig is a cylindrical body whose inner surface shape is the same as the cross-sectional shape of a spindle. The base member 13 has a slit S formed therein. The slit S is fixed to and released from the spindle by adjusting the interval of the slit S with a bolt 16.
[0019]
Next, a process of an inner surface grinding process using the electrode fixing jig 1 will be described with reference to FIGS. In internal grinding, first, a grindstone (metal-bonded grindstone) is selected according to the size and material of the workpiece. Examples of the grindstone include a cast iron bond diamond grindstone, a cast iron bond cBN grindstone, and a bronze-based metal bond grindstone. In addition, there are various diameters, and a grindstone of an appropriate type and diameter is selected for an object to be ground.
[0020]
After selecting the grindstone, the grindstone 100 is screwed into the rotating shaft 101 as shown in FIG. 3A, and the rotating shaft is further attached to the spindle. After attaching the grindstone, first, the truing (reshaping) of the grindstone is performed, and the eccentricity of the grindstone is removed to form. Then, the electrode fixing jig 1 is fitted into the spindle 102, and the bolt 16 of the electrode fixing jig 1 is tightened to fix it (FIG. 3B). When the fixing of the electrode is completed, the distance between the electrode 10 and the grindstone 100 is adjusted by the dial 21 of the electrode fixing jig. The distance between the electrode 10 and the grindstone 100 is about 0.1 to 0.3 mm. The rotating shaft 101 is covered with an insulating cover so that its surface is not eroded during the electrolytic dressing process.
[0021]
When the setting on the grindstone side is completed, the work W is fixed by the chuck 105 as shown in FIG. Further, a grinding liquid supply hose 106 for supplying a weakly conductive grinding liquid to the processing surface of the work W is installed in the grinding device.
[0022]
After the above setting of the grindstone and the work is performed, before the actual grinding process is started, first, the grindstone is electrolytically dressed to remove the binder on the grindstone grinding surface and to protrude the abrasive grains. In this electrolytic dressing, electricity is supplied using the grindstone 100 as an anode and the electrode 10 as a cathode. At this time, the anode (grinding wheel) is energized by installing a power supply brush (not shown) capable of contacting the rotating shaft in the spindle 102 and energizing the grinding stone and the electrode by the external power source 107. This energization is performed while repeatedly turning on and off the energization for a certain time. The energization conditions in the electrolytic dressing depend on the material of the material to be ground and the type of grinding wheel, but the peak voltage (Vp) is set to 60 to 150 V (set value) and the peak current value (Ip) is set to 5 to 15 A (set value). ), And the pulse on-time and off-time are each 2 μs.
[0023]
After the dressing of the grindstone is completed, the grindstone 100 and the work W are rotated, the spindle 102 is moved to the work W side, and the grindstone 100 and the inner surface of the work W are brought into contact with each other to start grinding. At this time, a grinding fluid is jetted from the grinding fluid hose 106 for cooling the processed surface and electrolytic dressing. In addition, this grinding is performed while reciprocating inside the workpiece in order to uniformly process the inner surface of the workpiece. In this grinding, the electrode and the grindstone are energized while performing the grinding in order to suppress the blinding of the grindstone processing surface accompanying the progress of the grinding, and the grinding is performed while performing the electrolytic dressing. The energization conditions at this time are as follows: in rough processing using a coarse-grained grindstone (approximately # 140 to 325), Vp is set to 60 to 150 V, Ip is set to 5 to 15 A, and the pulse on time and the off time are each set to 2 μs. In the processing with a fine-grain grindstone (# 2000 to 4000), Vp is set to 20 to 60 V, Ip is set to 2 to 5 A, and the pulse on time / off time is set to 2 μs each. In the processing, Vp is set to 20 to 30 V, Ip is set to 1 to 3 A, and the pulse on time and the off time are each set to 2 μs.
[0024]
By performing grinding while energizing as described above, for example, when using a # 4000 cast iron bond grindstone, the surface to be processed can be a mirror surface having a surface roughness Rmax of 0.1 μm or less. Further, in this machining process, machining was possible without a decrease in the grinding ability of the grindstone and without interrupting the work.
[0025]
【The invention's effect】
As described above, according to the present invention, electrolytic dressing, which has conventionally been applied only to surface grinding, can be applied to inner surface grinding (curved surface grinding). ADVANTAGE OF THE INVENTION According to this invention, precise and efficient processing can be performed about hard materials, such as ceramics and a cemented carbide, and brittle materials, such as glass.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electrode fixing jig according to an embodiment.
FIG. 2 is a diagram showing a structure of an adjusting unit.
FIG. 3 is a diagram showing a fixing jig attaching process.
FIG. 4 is a diagram showing an internal grinding apparatus to which the electrode fixing jig according to the embodiment is attached.
FIG. 5 is a diagram showing a conventional internal grinding apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electrode fixing jig 10 Electrode 11 Electrode support member 12 Adjusting means 13 Base member 14 Current supply cable 15, 16 Bolt 17 Moving part 18 Fixing member 19 Screw 20 Spring 21 Adjustment dial 100 Grindstone 101 Rotating shaft 102 Spindle 103 Grindstone 104 Saddle 105 Chuck 106 Grinding fluid supply hose 107 External power supply W Work S Slit

Claims (3)

Metal bond whetstone, a rotating shaft for attaching the whetstone, and an electrode fixing jig that can be attached to an inner surface grinding device including a spindle that rotates the rotating shaft,
A substantially L-shaped electrode composed of a power supply part parallel to the grinding wheel and the rotation axis and a fixed part perpendicularly intersecting the power supply part, an electrode support member for fixing the fixed part of the electrode and supporting the electrode, An electrode fixing jig for an internal grinding device, comprising: adjusting means for supporting an electrode supporting member and adjusting a distance between a grindstone and an electrode; and a base member supporting the adjusting means and fixed to the spindle. The electrode fixing jig according to claim 1, wherein the electrode support member is made of an electrically insulating material. The adjusting unit includes a moving unit that supports the electrode supporting member, and a fixed member that is fixed to the base member and supports the moving unit while guiding the movement of the moving unit.
The moving unit is movable by an elastic body sandwiched between the moving unit and the fixing member, and is position-fixable by a screw penetrating the fixing member from the moving unit,
3. The electrode fixing jig for an internal grinding device according to claim 1, further comprising a dial interlocked with said screw.

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