JP2003191164A - Precise grinding method and device, composite bond grinding wheel used therefor, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precise grinding method and a device having highly rigid (elastic modulus) bond base material, capable of performing super precise grinding, not only forming the projections of carbide abrasive grains by electrolytic dressing but also stably forming a chip pocket, and capable of retaining a superior cutting performance (grinding performance) for a long time and to provide a composite bond grinding wheel used therefore and its manufacturing method. <P>SOLUTION: A ceramic/metal composite bond grinding wheel 4 is molded by mixing fine carbide abrasive grains 5 with mean grain size of micro meter order, ceramic ultrafine grains 6 with the mean grain size smaller than the means grain size of the carbide abrasive grains, and metal ultrafine grains 7 with the mean grain size smaller than the carbide abrasive grains and solidifying them by hot press. Parts of the carbide abrasive grains are projected from the surface of the ceramic/metal composite bond grinding wheel viewed from a microscopically magnified state, at least, parts of the metal ultrafine grains near the surface of the ceramic/metal composite bond grinding wheel are electrolytically removed, and the chip pocket is formed in a recess formed after removing. The electrolytic dressing grinding is performed by the grinding wheel formed thereby. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision grinding method and apparatus for rotating an elongated workpiece around an axis, and bringing a rotating grindstone into contact therewith to grind it, a composite bond grindstone used therefor, and the same. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In plungers, cylinders, needle bearings, etc. of a fuel injection device (injection pump), it is necessary to finish an elongated work piece with high accuracy and high quality.

For example, in the case of an elongated shaft (or hole) having a diameter of 8 to 9 mm and a length of about 50 mm used as a plunger of an injection pump, the diameter tolerance ± is adjusted according to the inner diameter of the target cylinder (or plunger).
0.3 μm, Straightness 0.5 μm or less, Roundness 0.5 μm
The following high precision and high quality with a surface roughness Rz of 0.4 μm or less are required.

The material of the work piece is "tempered high carbon steel"
Alternatively, if the hardness is similar to this and is relatively easy to process, it can be ground with a grindstone using hard sand. However, to grind difficult-to-machine materials such as cemented carbide, silicon, glass, and ceramics with high accuracy and efficiency, ultra-high hardness abrasive grains such as diamond and CBN (cubic boron nitride) It is necessary to use a material obtained by molding (abbreviated as abrasive grain) with a bond material.

FIG. 12 (A) is a diagram schematically showing the structure of a grinding wheel in which cemented carbide grains are formed. The cemented carbide particles 1a in the normal state (A) are cross-linked (bridge-shaped) by a binder 1b, and pores 1c are formed in the gaps. The presence of such pores is important, and the pores located at the outermost layer are opened to the atmosphere to form the chip pocket 1d. Such a chip pocket 1d improves the sharpness (grinding performance) of the grindstone.

The presence of the tip pocket 1d is necessary for performing so-called ductile mode grinding. However, when the chips 3 generated by the grinding enter the chip pocket, the "clogging state" as shown in FIG. 12 (B) occurs, the sharpness of the grindstone becomes poor, and the brittle mode is ground, resulting in the ground surface. Becomes rough.

The cutting chips 3 are, when viewed in detail, a mixture of foreign matter derived from the work piece, foreign matter derived from a grindstone, and foreign matter derived from a grinding fluid (including oxides and polymerization products).

FIG. 13 (C) shows a "blind state" in which the cemented carbide grains are abraded as the grinding work is carried out and are not projected from the bond base. When this happens,
The sharpness of the grindstone becomes poor.

Therefore, the "clogging state" of FIG. 12 (B)
Alternatively, when the "blind state" of FIG. 13 (C) is reached, the surface of the grinding wheel is shaved with a diamond tool called a dresser to restore the "normal state" of FIG. 12 (A). This operation is called dressing.

In addition, as shown in FIG. 13 (D), when the binder is broken and the abrasive grains fall off in a "spilled state", the grinding wheel is not only sharp but also its diameter is reduced. , The dimensional accuracy of the grinding finish becomes poor.

Electrolytic in-process dressing (ELID) is proposed in order to prevent the drawbacks (clogging, crushing, spillage) of the conventional cemented carbide grindstones described above, or to reduce their adverse effects. Has been done.

FIG. 14 is a process chart of electrolytic in-process dressing (ELID), in which (A) # (E) represents each process. In each of these figures, each step is an enlarged schematic diagram of the vicinity of the surface of the grindstone, and the upper side is the surface that performs the grinding action.

The ELID grindstone is formed by forming cemented carbide grains with a conductive pouring agent.

The conductive bond agents are roughly classified into a. cast iron,
A metal material such as bronze, b. There is a conductive resin (that is, a resin / metal composite bond), each of which has a length.

Here, the fact that the bonding agent is conductive means that the surface layer can be removed electrolytically by a means similar to electrolytic polishing, so that it can be dressed by utilizing the phenomenon of anodic oxidation in electrochemistry. It was devised.

In addition to the above a and b, a technique of using a ceramic as a bonding agent is also known, but since it has no conductivity, it cannot be electrolytically dressed and is outside the scope of the ELID technique.

Further, in order to perform precision grinding, it is necessary to make abrasive grains or bond grains fine (micrometer order). However, when fine ceramic powder is used as the bonding agent, the pores described above with reference to FIG. 12 are generated. There is a technical problem that it will not be formed, and it has not been solved yet.

Each step of electrolytic in-process dressing (ELID) will be described below with reference to FIG.

FIG. 14A shows a state in which cemented carbide grains are mixed into fine particles of a bonding agent and hot press molded.
If the bonding agent is metal powder, it is in a "sintered" state, but in the case of a resin bonding agent, it is hard to say "sintered".
I decided to call it a hot press. Therefore, in the present invention, the term "hot pressing" includes "sintering".

In this state, the cemented carbide grains 5 are not necessarily the surface of the bond base material (abbreviated as the bond base) (upper surface in the figure).
It doesn't stick out.

Therefore, when the surface layer of the bond group 26 is electrolytically removed, the surface layer of the bond group disappears and the cemented carbide grains 5 project to the surface as shown in FIG. 14 (B). That is, it is dressed.

As this electrolytic dressing progresses,
As shown in (C), the metal oxide film 27 (with spots)
Is formed. This metal oxide film is, for example, ferrosoferric oxide or iron hydroxide, and has a high electric resistance. Therefore, electrolytic dressing is suppressed and electrolytic removal does not proceed. Even in the case of the resin bond agent, the conductive resin contains a metal component, so that an oxide film is formed.

When the grinding work is performed with the grindstone in the state shown in FIG. 14C, the sharpness is good. But if you continue grinding,
Gradually, the surface of the grindstone is worn as shown in (D), the protruding portion of the cemented carbide grain 5 is worn away, and the sharpness decreases.

However, along with this, the oxide film 27 becomes thin as shown in (E), the amount of electricity is increased, and the electrolytic removal of the bond group 26 proceeds.

The above-mentioned (C) → (D) → (E) → (C)
Is called an ELID cycle. However, in reality, the "dressed state" is maintained in a manner close to the steady state while the formation of the oxide film 27 and the abrasion are balanced.

[0026]

As described above, "a grinding wheel in which cemented carbide particles are dispersed in a conductive bond (bonding agent) is formed, and the surface layer of the bonding agent is electrolytically removed to dress. The technology to do is being developed.

Electrolytic in-process dressing (ELID) grinding, in which electrolytic dressing is performed in parallel with grinding (in-process), is in the spotlight. The present invention focuses on high precision and high quality of ELID grinding, drastically improves the structure of the grindstone, and pursues ultrahigh precision and high quality rotary surface grinding finish. That is, the present invention is not limited to "in-process", but covers both in-process dressing and interval dressing.

In order to electrolytically remove the bond group, the bond group must contain an ionizable conductive substance. From this point of view, known conductive bonds are roughly classified into metal bonds and resin-metal composite bonds.

There are cast iron-based and bronze-iron-based metal bonds as the metal bond, but since unevenness is generated on the surface subjected to electrolysis, ultra-high precision grinding becomes difficult. In particular, in the in-feed grinding of the centerless grinding method, the straightness of the ground surface cannot be secured.

Further, when the surface layer of the metal bond is electrolytically removed, "protrusion of cemented carbide grains" is obtained, but it is conventionally difficult to form the pores (chip pockets) described in FIG. 12, and the sharpness is unsatisfactory. there were.

On the other hand, when the surface layer of the resin-metal composite bond is electrolytically removed, the metal component is selectively ionized and removed, and the recesses thereafter form pores (chip pockets), so the sharpness is good, but the resin is Generally, rigidity (elastic coefficient) is low. Therefore, it is easily elastically deformed, and it is difficult to finish it to an accurate size. For example, in the centerless grinding, the actual grinding amount is 0.5L # 0.7L with respect to the cutting amount of the minute length L. (0.3L #
If 0.5L, the bond base of the grinding wheel is distorted and absorbed). Further, since the ratio of the amount of grinding / the amount of cutting is not constant, it was not possible to finish the grinding with accurate dimensions.

The present invention has been made in view of the above circumstances. That is, the object of the present invention is that the bond base material has a high rigidity (elastic coefficient), ultra-high precision grinding is possible, and not only the protrusion of the cemented carbide grains is formed by electrolytic dressing, but also the chip pocket is stable. The present invention provides a precision grinding method and device which are formed by the above method and can maintain good sharpness (grinding performance) for a long time, a composite bond grindstone used for the same, and a manufacturing method thereof.

[0033]

The basic principle of the present invention for achieving the above object will be briefly described with reference to the embodiments.

In FIG. 1, the columnar member 11a can be highly efficiently manufactured without mechanically dressing the grinding wheel 4.
The inner diameter of the cylindrical member 14a is measured by the inner diameter measuring device 15 in order to grind and finish the surface of the cylindrical member 14a with high accuracy and excellent finish and to fit the finished cylindrical member 14a properly. The lower slide 8a and / or the horizontal turning disk 8b of the centerless grinding machine 8 are adjusted based on the measured value.

On the other hand, the grinding wheel 4 is made of a ceramic metal material in which cemented carbide particles 5, ceramic fine particles 6 and metal fine particles 7 are mixed, and an electrode member 13 is opposed to the ceramic metal grinding wheel 4 to leave a gap. It is installed and electrolytically removes a part of the metal component on the surface of the ceramet abrading grindstone 4 with a conductive grinding liquid interposed to cause the cemented carbide abrasive grains 5 to protrude and form a chip pocket.

Based on the above-described principle, the method according to the first aspect of the present invention is configured such that the cemented carbide grains which are fine particles having an average grain size of the order of micrometers and the average grain size of the cemented carbide grains are previously set. Ceramic ultra-fine particles having a small average particle size,
A grinding wheel (4) is constituted by a ceramic-metal composite bond wheel formed by mixing metal ultra-fine particles having an average particle diameter substantially equal to that of the ceramic ultra-fine particles and hot pressing the mixture, and a microscope From the surface of the ceramic-metal composite bond grindstone in an expanded state, and if a part of the cemented carbide grains are protruding, and at least metal ultrafine particles near the surface of the ceramic-metal composite bond grindstone It is characterized in that a part is electrolytically removed to form a chip pocket in the recess after the removal, and the workpiece is ground by this grinding wheel.

According to the above-mentioned method of claim 1, since the ceramic ultrafine particles (6) forming the ceramic-metal bond base are not subjected to electrolysis, only the metal ultrafine particles (7) are eluted and the chip Form a pocket and have a dressing effect. Further, since the ceramic bond portion, which is not eluted and remains porous, has high rigidity, ultra-precision grinding finish is possible.

In addition to the constituent features of the method of claim 1 (see FIG. 1), the method according to claim 2 includes a cylindrical workpiece (11b), an adjusting grindstone (10) and a blade (9). ) And are rotated while being supported, the grinding wheel (4), which is a grinding wheel, is brought into contact with the cylindrical workpiece to perform centerless grinding. By this method, centerless grinding can be performed with high accuracy and high efficiency. In addition to the constituent features of the method of claim 2 (see FIG. 1),
Based on the given finished cylindrical member (14a) as a reference, the outer periphery of the unfinished cylindrical member (11a) is ground so as to be fitted properly to the cylindrical member (14a). The inner diameter of the cylindrical member is measured, and based on the measured value, the cylindrical member (11
The target value of the finishing dimension of a) is calculated, and the lower slide (8a) of the centerless grinding machine (8) and the horizontal turning disk (8) are calculated.
At least one of b) is adjusted based on the target finish dimension value, the outer peripheral surface of the cylindrical member is ground, and the cylindrical member (14b) whose inner diameter dimension has been measured, and the ground cylindrical member The member (11c) is paired and the pair is held and handed over to the next step.

According to the above-mentioned method of claim 3, the cylindrical member (14a) that has been subjected to the finishing process is ground with extremely high precision so that the cylindrical member (11a) which is the workpiece is fitted. be able to. The method of claim 2 is particularly effective when the dimensional variation of the finished surface of the inner peripheral surface of the cylindrical member is relatively large. In addition to the constituent features of the method of claim 3 (see FIG. 1),
While the grinding wheel (4) composed of the ceramic-metal composite bond grindstone is being rotated, the outer peripheral surface of the grinding wheel is being processed while the outer peripheral surface of the cylindrical member that is the processing object is being ground. In a region not in contact with (11b), an electrode member (13) is arranged facing the outer peripheral surface thereof with a gap, and a conductive grinding fluid is supplied to the gap between the grinding wheel and the electrode member. Then, a positive voltage is applied to the grinding wheel and a negative voltage is applied to the electrode member to electrolytically remove the ultrafine metal particles.

According to the above-mentioned method of claim 4, while the workpiece is ground by the ceramic-metal composite bond grindstone (4), the dressing of the ceramic-metal composite bond grindstone is concurrently performed, and the ceramic The metal composite bond grindstone can always be kept well dressed. The structure of the method according to claim 5 (see FIG. 2) is a cylindrical member (18
b) is chucked concentrically with respect to the spindle (20a) of the headstock (20), and the inner peripheral surface of the cylindrical member is provided by a rotary grindstone (23a) attached to a grindstone shaft rotation / forward / backward drive mechanism (25). In the method of grinding, in advance, the average particle size is a cemented carbide grain that is a fine particle of the order of micrometers, and an ultrafine grain of a ceramic having an average grain size smaller than the average grain size of the cemented carbide grain, The rotary grindstone (23a) is constituted by a ceramic-metal composite bond grindstone obtained by mixing ultrafine metal particles having an average particle diameter substantially equal to that of ceramic superhard abrasive particles and hot pressing the mixture. , A metal in the vicinity of the surface of the ceramic-metal composite bond grindstone, in which a part of the cemented carbide grains protrude from the surface of the ceramic-metal composite bond grindstone in a microscopically enlarged state At least a portion of the fine grains by electrolytic removal, to form a chip pocket recess after removal,
It is characterized in that the inner peripheral surface of the cylindrical member is ground by this rotating grindstone.

According to the above-mentioned method of claim 5, it is not necessary to perform mechanical dressing, and the rotary grindstone (2
3a) can be dressed in a sharp state, and the inner peripheral surface of the cylindrical member (18b) that is the workpiece can be ground and finished with high efficiency and high accuracy. In addition to the constituent features of the method of claim 5 (see FIG. 2), the structure of the method according to claim 6 provides a cylindrical member (1
7a) as a reference, the inner circumference of the unfinished cylindrical member (18a) is ground so as to be fitted properly thereto, and the outer diameter dimension of the finished cylindrical member is measured. At the same time, a finish dimension target value of the cylindrical member (18a) is calculated based on the measured value, and the grindstone shaft rotation / forward / backward drive mechanism (25) is adjusted based on the finish dimension target value. A cylindrical member (17b) whose inner peripheral surface has been ground with a rotary grindstone (23a) and the measurement of the outer diameter dimension has been completed, and a ground cylindrical member (18c).
And are paired, and this pair is held and handed over to the next step.

According to the above-mentioned method of claim 6, the cylindrical member (18a), which is the workpiece, is properly fitted to the finished cylindrical member (17a) as a reference. It can be ground. The method of claim 5 is suitable when the accuracy of the cylindrical member grinding means is higher than the accuracy of the cylindrical member grinding means. In addition to the constituent features of the method according to claim 6 (see FIG. 2), the method according to claim 7 has the result that the inner peripheral surface of the cylindrical member is ground by the rotating grindstone (23 a). When the surface condition of the wheel deteriorates, the grinding work is temporarily interrupted, the rotary grindstone is removed from the drive mechanism (25), the rotary grindstone is positioned facing the electrode (22a) with a gap, and the gap is removed. The electrolytic removal of ultrafine metal particles is performed by applying a positive voltage to the rotating grindstone and a negative voltage to the electrodes while the electrolytic solution is interposed between the electrodes.

According to the above-mentioned method of claim 7, the inner diameter of the cylindrical member (18b) is small and the rotary grindstone (23a) is small.
This rotary whetstone can be electrolytically dressed even if there is little difference from the outer diameter dimension of. The method according to claim 8 is configured such that the electrolytic removal is performed using electrolytic dressing,
The electrolytic dressing is ground without being electrolyzed during rough processing, and during finishing or mirror finishing, electrolysis is continuously or intermittently applied depending on the processing step and processing quality, whereby fine abrasive grains are obtained. It is characterized by controlling and maintaining the protrusion.

According to the above-mentioned method of claim 8, it is possible to perform grinding by using electrolytic dressing when necessary (during finishing or mirror finishing). Further, this electrolytic dressing can be performed continuously or intermittently (at intervals) in accordance with the processing step and processing quality to finely control and maintain the projection of abrasive grains. The configuration of the device according to claim 9 is (see FIG.
On the bed (12), lower slide (8a)
And an adjusting grindstone (10) mounted via a horizontal turning disk (8b), a blade (9) that supports a cylindrical member (11b) that is a workpiece in cooperation with the adjusting grindstone, and the cylindrical shape. In a centerless grinding machine having a grinding wheel (4) which is a grinding wheel that contacts a member and grinds the member, the grinding wheel (4) is made of cemented carbide particles that are fine particles of a micrometer order and the cemented carbide. Ceramic-metal bond grindstone formed by mixing ceramic ultrafine particles smaller than the average particle size of abrasive grains and metal ultrafine particles having an average particle size substantially equal to the ceramic ultrafine particles, and hot pressing the mixture. The ceramic-metal composite bond grindstone has a part of the cemented carbide particles protruding from the surface thereof, and at least a part of the ultrafine metal particles near the surface of the ceramic-metal composite bond grindstone. Electropolished removed, the recess after it has been removed, characterized in that to form a chip pocket.

According to the above-mentioned invention of claim 9, the outer peripheral surface of the cylindrical member (11b) can be centerless ground with ultra-high precision and excellent surface roughness, and it is necessary to provide a mechanical dresser. Absent. In addition to the constituent features of the device according to claim 9 (see FIG. 1), the structure of the device according to claim 10 is such that the cylindrical member (11 a) that is the workpiece is a cylindrical member (finished). 14a) as a reference, which is to be ground so as to be fitted properly thereto, and an inner diameter measuring device (15) for measuring an inner diameter dimension of the cylindrical member, and an output of the inner diameter measuring device. Input the signal,
An automatic control circuit (16) for controlling the lower slide (8a) and / or the horizontal turning disk (8b) of the centerless grinding machine (8).

According to the apparatus of claim 10 described above, the cylindrical member (14a) that has been finished is used as a reference, with high efficiency so that the cylindrical member (11a) that is the workpiece is properly fitted, Moreover, it is possible to grind with excellent surface roughness and ultra-high accuracy. In addition to the constituent features of the device according to claim 9 or 9 (see FIG. 1), the device according to claim 11 is installed facing the outer peripheral surface of the grinding wheel (4) with a gap. An electrode member (13), a grinding liquid nozzle (8d) for supplying a grinding liquid to a gap between the electrode member and the grinding wheel, a negative voltage for the electrode member, and a positive voltage for the grinding wheel. It is characterized in that it comprises an applying means for applying each.

According to the above-mentioned apparatus of claim 11, while performing the grinding work of the cylindrical member by the centerless grinding machine (8), the grinding wheel (4) is simultaneously dressed at the same time. The surface state of can be always maintained in good condition. Therefore, it is not necessary to interrupt the grinding work and perform dressing, and the grinding process can be performed with higher efficiency. The structure of the device according to claim 12 (see Fig. 2) comprises a headstock (20) having chuck means (20b) for chucking a cylindrical member (18b) and a spindle (20a) on which the chuck is mounted. A rotating grindstone (23a) having an outer diameter dimension smaller than the inner diameter dimension of the cylindrical member, and a grindstone shaft rotating / backward / rearward direction for mounting the rotating grindstone and rotating the grindstone in the axial direction. In the inner peripheral surface grinding machine equipped with the advancing drive mechanism (25), the rotating grindstone (23a) is made of cemented carbide grains that are fine particles of the order of micrometers, and a ceramic ultrafine grain smaller than the average grain size of the cemented carbide grains. Ceramics obtained by mixing the particles and the metal ultrafine particles having an average particle diameter substantially equal to the ceramic ultrafine particles and hot pressing
It is a metal bond grindstone, and in the ceramic / metal bond grindstone, a part of the ultra-fine particles protrudes from the surface thereof, and at least a part of the ultrafine metal particles near the surface of the ceramic / metal bond grindstone is electrolyzed. It is characterized in that the recess, which has been removed and which has been removed, forms a chip pocket.

According to the apparatus of claim 12 described above, since the rotary grindstone (23a) is composed of a ceramic-metal-bonded grindstone, good sharpness can be obtained by electrolytically dressing this, and furthermore, electrolytic dressing is performed. Since the rotating grindstone has high rigidity in this state, ultra-precision grinding finish is possible. In addition to the constituent features of the apparatus according to claim 12 (see FIG. 2), the apparatus according to claim 13 has a columnar member (18a, 18b), which is the workpiece, having a finished cylindrical shape. An outer diameter dimension measuring device (19) for measuring the outer diameter dimension of the finished cylindrical member, which is to be ground so as to be properly fitted to the member (17a) as a reference. And an automatic control circuit (21) for controlling the grindstone shaft rotation / forward / backward drive mechanism (25) in accordance with the output signal of the outer diameter dimension measuring device, and mounted on the grindstone shaft rotation / forward / backward drive mechanism. Supporting means for rotatably supporting the rotatable grindstone by removing it, an electrode (22a) installed with a gap facing the rotatable grindstone (23b) rotatably supported, and the rotary grindstone Positive voltage against Power source for applying a negative voltage to, and characterized by comprising an electrolyte supply means for supplying electrolytic solution (22) in the gap between the grindstone and the electrode.

According to the above-mentioned apparatus of claim 13, the inner peripheral surface of the cylindrical member which is the object to be processed is ground so as to be fitted properly with the cylindrical member, which is the workpiece, with the finished cylindrical member as a reference. You can do it.

Even if the inner diameter of the cylindrical member is small and the spare space is small when the rotary grindstone is inserted, the rotary grindstone can be electrolytically dressed, so that the sharpness of the rotary grindstone is improved. Can be maintained. Claim 1
The apparatus according to No. 4 is equipped with an electrolytic dressing device for performing the electrolytic removal, and the electrolytic dressing device performs grinding without applying electrolysis during rough processing, and performs a processing step and processing quality during finishing processing or mirror surface processing. Depending on the above, electrolysis is continuously or intermittently applied to finely control and maintain the projection of abrasive grains.

According to the apparatus of claim 14 described above, grinding can be performed when necessary (during finishing or mirror-finishing) by using the electrolytic dressing device. Further, the electrolytic dressing device can be continuously or intermittently (at intervals) depending on the processing step and processing quality to finely control and maintain the projection of abrasive grains. Further, in FIG. 6 to be described later, fine particles of cemented carbide grains 5 (average grain size on the order of micrometers), ceramic ultrafine grains (average grain size is smaller than the cemented carbide grains) 8, and metal ultrafine grains 9. Are mixed in step 31 and hot pressed in step 32 to form a cylindrical or annular grindstone body 33 (arrow c). On the other hand, a base metal 30 of a pair different from the above is created, and the whetstone body 33 and the base metal 30 are
And are joined (arrows d and d ′) to form a semi-finished product 35.
In step 36, this is electrolytically finished (initial dressing) to obtain a product. With respect to this principle, the structure of the method according to claim 15 comprises fine cemented carbide grains (5) having an average grain size of the order of micrometers and ceramics having an average grain size smaller than the average grain size of the cemented carbide grains. Characterized in that ultrafine particles (6) and metal ultrafine particles (7) having an average particle size smaller than the average particle size of the cemented carbide abrasive grains are mixed and solidified by hot pressing to be molded. To do.

According to the above-mentioned method of claim 15, since the cemented carbide grains (5) are fine grains of the order of micrometers, a bond grindstone capable of grinding and finishing a good mirror surface in the dressed state is constituted. Moreover, since the bond group is composed of a mixture of "ceramic ultrafine particles of high rigidity and non-electrolyte" and "electrolytically removable metal ultrafine particles", the state of electrolytically dressed Since the surface layer is made porous to form the chip pocket, the cutting performance is good, and the rigidity is high in the dressed state, and ultra-high precision grinding is possible. When the method of claim 13 is implemented,
As the metal ultrafine particles (6), ultrafine particles of a metal material mainly composed of a metal element having an atomic number of 24 to 29 are used.

According to the above-mentioned method of claim 16, chrome of atomic number 24, manganese of 25, iron of 26,
Cobalt No. 27, Nickel No. 28, and Copper No. 29 are solid at room temperature, nontoxic, easy to handle, and have an affinity for cemented carbide grains and ceramics, making them suitable for hot pressing. ing. In addition, any of them can be anodized into metal ions, so that electrolytic dressing is possible. Moreover, these metals are mass produced and relatively inexpensive. The structure of the method according to claim 17 is the same as the constituent requirements of claim 15 or 14, in addition to the ceramic ultrafine particles (6), an oxide, a silicide, a boride,
It is characterized in that at least one, preferably a plurality of nitrides, carbides or interoxides are mixed and used.

According to the above-mentioned method of claim 17, the bond material composed of these compounds has an affinity for the cemented carbide grains and the metal grains. In other words, since it has bondability to cemented carbide grains and metal grains in a partially heat-softened state, and has sufficient rigidity at around room temperature, a grindstone made of these materials as a binder has high rigidity. It is suitable for ultra-high precision grinding. In addition to the constituent features of the method according to any one of claims 15 to 15, the method according to claim 18 further includes the cemented carbide abrasive grains (5), ceramic ultrafine grains (6), and metal ultrafine grains (7). When mixing and solidifying by hot pressing, base metal of grinding wheel (30)
A cylindrical or annular grindstone body (33) without insert molding, or grindstone segments (37a, 37b, 37c) obtained by dividing these into a separate piece from the grindstone body or grindstone segment. It is characterized in that a base metal (30) is formed so as to be fitted with the base metal, and the base body or the base of the grindstone is joined to the base metal to form a grindstone assembly for grinding.

According to the above-mentioned method of claim 18, the hot press forming of the grindstone main body (33) and the preparation of the base metal (30) are carried out separately and then the two are joined, so that the grindstone main body is formed. There is no risk of cracking due to the difference in coefficient of thermal expansion between the fine ceramic that is used and the steel material that forms the base metal, and for the same reason, residual stress does not occur in the product. Obtainable.
In addition to the constituent features of the method according to claim 17, the method according to claim 19 is characterized in that after the cylindrical or annular grindstone body (33) is formed by hot pressing, the outer periphery of the grindstone body is formed. While facing the surface and positioning the electrode member with a gap, and filling the gap between the two with the electrolytic solution,
A positive voltage is applied to the grindstone body and a negative voltage is applied to the electrode member to selectively remove only the ultrafine metal particles (7) located on the surface layer portion of the outer peripheral surface of the grindstone body. The chip pocket (1d) is formed by the recess after the fine particles have disappeared, and a part of the cemented carbide particles (5) remaining without being removed is projected from the surface of the bond base to form a cutting edge. And imparts grinding performance as a grinding wheel.

According to the above-mentioned method of claim 19, the outer peripheral surface of the cylindrical or annular grindstone main body constituted by applying claim 18 is smoothed by hot press molding. A product having a cutting edge and a chip pocket is prepared to be ready for use immediately. The structure of the composite bond grindstone according to the invention of claim 20 is a bond grindstone in which cemented carbide grains (5) are dispersed in a bond base, wherein the cemented carbide grains are fine particles with an average grain size of the order of micrometers. Yes, and the bond base is ceramic ultrafine particles (6) and metal ultrafine particles (7)
Are mixed and formed, and the average particle size of these ultrafine particles is smaller than the average particle size of the cemented carbide abrasive grains.

In the composite bond grindstone according to the above-mentioned 20th aspect of the present invention, since the bond base is formed by the ceramic ultrafine particles and the metal ultrafine particles, the metal ultrafine particles are generated by electrolyzing the bond group. By selective electrolytic removal, chip pockets corresponding to the size of ultrafine particles are formed, and the sharpness (grinding performance) of the grindstone is good. In addition, the ultrafine ceramic particles that remain without being electrolyzed form a structure bridging with each other and exhibit high rigidity. Therefore, ultra-high precision grinding is possible. The structure of the composite bond grindstone according to the invention of claim 21 is such that, in addition to the constituent features of the invention according to claim 19, the metal ultrafine particles (7) are a metal element of atomic number 24 to atomic number 29, That is, it is characterized by being mainly composed of any one metal material of chrome, manganese, iron, cobalt, nickel and copper, or a plurality of metal materials.

According to the twenty-first aspect of the present invention, the metal material forming the ultrafine metal particles is solid at room temperature, has the physical properties of being sintered by hot pressing, and is nontoxic, so that it is easy to manufacture. Moreover, since it is chemically relatively stable, it is easy to guarantee the quality retention. Moreover, since these metal materials are industrially mass-produced and supplied, they can be obtained inexpensively and stably. In the structure of the composite bond grindstone according to the invention of claim 22, in addition to the constituent requirements of the invention according to claim 19, the metal ultrafine particles are any one of chrome, manganese, iron, cobalt, nickel and copper. It is characterized in that it contains ultrafine particles composed of one elemental metal material, or contains at least one alloy material of chromium, manganese, iron, cobalt, nickel and copper.

According to the twenty-second aspect of the present invention, the melting point, sintering temperature, coefficient of thermal expansion, ductility, The malleability, hardness, toughness, and other physical properties can be changed, and the change in the physical properties can be adjusted by adjusting the addition amount of the other substances described above. , It is possible to prevent cracks from occurring due to hot pressing. The structure of the composite bond grindstone according to claim 23 is
In addition to the constituent features of the invention according to claim 19, the ceramic ultrafine particles (6) include an oxide, a silicide, a boride,
It is characterized by being a fine ceramic containing at least one of a nitride, a carbide and an interoxide compound.

According to the twenty-third aspect of the present invention, since the non-metallic material forming the ceramic ultrafine particles is an electric insulating material and is not ionized, it does not elute even when subjected to an electrolytic treatment, and after the electrolytic treatment. In the above, the ultrafine particles have a high rigidity by bridging each other, and also have a heat-welding property with respect to the cemented carbide abrasive grains, which hardly causes spillage of the cemented carbide abrasive grains and has excellent durability. ing. According to the structure of the composite bond grindstone according to the invention of claim 24, in addition to the constituent requirements of claim 19 to claim 20, the bond grindstone has a base metal functioning as a boss for mounting the rotary shaft at a central portion thereof. A grindstone body (33) or a grindstone segment (37a, 37b) having a cylindrical shape or an annular shape, which has (30) and in which the cemented carbide grains (5) are dispersed in the bond base on the outer periphery thereof. , 3
7c) and a separate base metal, and the grindstone body or the grindstone segment are joined to each other.

According to the twenty-fourth aspect of the present invention, since the bond grindstone is formed separately from the base metal (30), there is no risk of cracking due to the difference in thermal expansion from the base metal during hot pressing. In addition, it is possible to reduce the manufacturing cost by forming the bond grindstone main body portion, which is relatively expensive to manufacture, into a thin wall. The structure of the composite bond grindstone according to the invention of claim 25, in addition to the constituent features of the invention of claim 23, includes the cylindrical or annular grindstone body (33) or the grindstone segment (37a, 37b, 37c). , At least a part of the metal ultrafine particles (7) forming the bond base are removed on the surface layer portion of the surface functioning as a grinding wheel, and the removed traces form ultrafine recesses. It is characterized by being

According to the twenty-fifth aspect of the present invention, the main body (3) of the bond grindstone hot pressed during the manufacturing process is used.
3) or a part of the ultrafine metal particles in the surface layer portion of the segment (37a, 37b, 37c) is removed, so that a part of the cemented carbide grain relatively protrudes from the surface layer to form a cutting edge. The removed recesses function as chip pockets, and the desired grinding performance (sharpness) is achieved.

That is, by applying claim 25 to the composite bond grindstone according to the invention of claim 24,
It can be completed as a product if the "obtained end user can immediately use it".

[0064]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same parts are designated by the same reference numerals, and duplicated description will be omitted. FIG. 1 is a schematic diagram showing a first embodiment of the present invention. In this figure, reference numeral 8 is a centerless grinding machine, and an adjusting grindstone 10 is mounted on a bed 12 through a lower slide 8a, a horizontal turning disk 8b, and an upper slide 8c in this order, and a horizontal turning disk. A blade 9 is mounted on 8b.

The grinding wheel 4 of this embodiment is made of ceramic.
It is a metal composite bond (abbreviation: Cerameta) grindstone. Figure 3
FIG. 4 is a diagram schematically showing an enlarged cross section near the surface of a ceramet grindstone.

Reference numeral 5 (5a # 5e) is a cemented carbide grain.
The cemented carbide grains are fine grains having an average grain size of the order of micrometers. The use of such fine cemented carbide grains is one of the conditions necessary for reducing (smoothing) the surface roughness of the ground surface. The average particle size of the cemented carbide grains is about 5 to 10 μm (# 2500) in the examples described later, but it may be smaller than this, for example, 4 μm or less. As a bonding agent for bonding the cemented carbide grains 5,
A mixture of ceramic ultrafine particles 6 and metal ultrafine particles 7 is used.

The super hard abrasive grains (super high hardness abrasive grains) 5a # 5e are fine particles of the order of micrometers, but the ceramic ultra fine grains 6 and the metal ultra fine grains 7 are finer than the super hard abrasive grains 5. And mix. It is desirable to have at least an average particle size smaller than that of the cemented carbide grains. The average particle size of the ceramic ultrafine particles 6 and the metal ultrafine particles 7 is about 2 μm in the examples described later, but when the cemented carbide abrasive grains 5 are 4 μm, the average particle size is smaller than this, for example, 1 μm or less. Is good. For cemented carbide grain 5,
The average particle size of the ceramic ultrafine particles 6 and the metal ultrafine particles 7 is reduced by making the cemented carbide abrasive grains 5 into a bridge shape with a ceramic-metal composite bond base composed of the ceramic ultrafine particles 6 and the metal ultrafine particles 7. This is for supporting and for forming a chip pocket having a size suitable for grinding when the ultrafine metal particles 7 on the surface are removed by electrolytic dressing.

Here, "super-hard abrasive grains" mean that the hardness is extremely high, and "ultra-fine grains" mean that the grain size is very small. The cemented carbide grains are made of diamond or CBN, and the ultrafine grains are grains having an average grain size of several μm. The numbers of the ceramic ultra-fine particles 6 and the number of the metal ultra-fine particles 7 shown in FIG. 3 are close to 100, so that only one of them is given the reference numeral 6 to exemplify the ceramic ultra-fine particles. The other 100 ultra-fine ceramic particles are shown with spots. Similarly, a little less than 100 ultrafine metal particles are indicated by hatching. The upper side of the figure is the surface of the grindstone (the surface to be ground), and the lower side of the figure is the inner side of the grindstone.

FIG. 3 schematically shows a desirable state as a grindstone for grinding, in which a part of the cemented carbide grains 5 is projected on the surface of the grindstone. Therefore, the sharpness is good. When the grinding operation is performed in the state of FIG. 3, the protruding portions of the cemented carbide grains 5 are gradually worn away, and the protruding portions disappear as shown in FIG. In this state, the grindstone for grinding has no "cutting edge" and no chip pocket, resulting in poor sharpness, and if you grind with a strong force, it will be in a brittle mode grinding state and the grinding surface will be rough (surface roughness is growing).

Then, as described later, when the surface of the ceramic cement grindstone 4 is electrolytically dressed, only the ionizable substance (that is, the ultrafine metal particles 7) is electrochemically anodized and the electrolytic solution is applied. Elutes in. For this reason, as shown in FIG. 5, the ultrafine metal particles 7 existing on the surface layer portion on the grindstone surface side (upper surface in the figure) disappear or become thin and shrink, and then a recess is formed. This recess forms the chip pocket 4a.

The ceramic cemented carbide grains 6 (with spots) that are not subjected to electrolysis remain in a bridging manner in principle, but a part thereof falls off as the metal cemented carbide grains 7 (hatching) disappear. . As a result, a part of the cemented carbide abrasive grains protrudes to the surface side of the grindstone to form a cutting edge, and in combination with the formation of the chip pocket 4a, an excellent sharpness is exhibited. That is, a dressing effect is produced. Although the operation of the electrolytic dressing described with reference to FIGS. 3 and 4 can be performed by temporarily interrupting the grinding work, in the embodiment of FIG. 1, the grinding work is not interrupted and is performed concurrently with the grinding work. And in-process. In FIG. 1, the electrode member 13 was arranged facing the outer peripheral surface of the ceramic metal grinding wheel 4 with a gap. This member 13 is a stationary member with respect to the bed 12 of the centerless grinding machine 8 (position adjustment is possible, but it does not rotate like a grinding wheel).

Further, a conductive grinding fluid is supplied from the grinding fluid nozzle 8d toward the gap between the electrode member 13 and the cerameta grinding wheel 4. This grinding fluid also serves as an electrolyte.

Further, a negative voltage is applied to the electrode member 13 and a positive voltage is applied to the cerameta grinding wheel 4. As a result, the surface of the ceramic metal grinding wheel 4 is electrolytically dressed. In the embodiment shown in FIG. 1, the inner peripheral surface of each cylindrical member 14a that has been finished is used as a reference, while the outer peripheral surface of the unfinished cylindrical member 11a that is the workpiece is centerless ground. For proper fitting.

Under normal working conditions, the machining accuracy of the outer peripheral surface of the cylindrical member is generally much higher than the machining accuracy of the inner peripheral surface of the cylindrical member.

In view of these circumstances, in this embodiment,
For each "cylindrical member that has a large variation in finished size when mass-produced", use an "ultra-fine size control centerless grinding machine" to grind each cylindrical member so that it fits Of. Based on the new technical idea as described above, the finished cylindrical member (reference member) 14a is carried into the inner diameter measuring device 15 (arrow a).
Then, the output signal representing the measurement result is input to the automatic control circuit 15 as indicated by an arrow b. The automatic control circuit 15 analyzes the information on the inner peripheral surface of the finished cylindrical member 14a which is the reference member. That is, the inner diameter dimension and the taper amount are read.

Then, a command signal (arrow b) is given to the centerless grinding machine 8 and (a) the lower slide 8a is controlled so that the outer diameter of the cylindrical member 11b, which is the workpiece, is adjusted to an appropriate value. And / or (b) horizontal swivel plate 8b
Is controlled to make the taper amount of the cylindrical member 11b, which is the workpiece, appropriate. The unfinished cylindrical member 11a is carried into the centerless grinding machine 8 controlled in this way (arrow e). The cylindrical member 14b that has been measured by the inner diameter measuring device 15 is stored in the matching pallet 24 as indicated by an arrow c, and the cylindrical member 11c ground so as to match the cylindrical member 14b is also indicated by an arrow. It is stored in the matching pallet 24 like f.

In this way, the cylindrical member 14b serving as the reference and the cylindrical member 11 which is ground in conformity with the cylindrical member 14b.
c is paired, and this pair relationship is maintained and the process is passed to the next step (for example, fitting state inspection). This pair is, for example, an injection pump cylinder and a plunger. FIG. 2 is a system diagram showing an embodiment different from the embodiment of FIG. 1 described above. Differences from the embodiment of FIG. 1 described above and the same or similar points are summarized as follows.

(B) Differences The workpiece in the embodiment shown in FIG. 1 is a cylinder, but in FIG. 2 it is a cylinder. Along with this, the outer peripheral surface is ground and finished in FIG. 1, and the inner peripheral surface is ground and finished in FIG. Then, in FIG. 1, the cylinder is ground based on the cylindrical shape, and in FIG. 2, the cylinder is ground based on the cylinder.

In FIG. 1, the outer peripheral surface of the cylinder is ground by the centerless grinding wheel, but in FIG. 2, the inner peripheral surface of the cylinder is ground by the rotary grinding wheel (reference numeral 23a). (B) Same or similar points The grinding wheel (reference numeral 4) in FIG. 1 was a member in which fine particles of cemented carbide abrasive grains were formed using a mixture of ceramic ultrafine particles and metal ultrafine particles as a binder. The rotary grindstone (23a) in FIG. 2 is also the same material, that is, the ceramet grindstone described above with reference to FIG. In FIG. 2A, the unfinished cylindrical member 18a is the workpiece in this embodiment. Grinding the cylindrical member 18a so as to fit the finished cylindrical member 17a properly is the problem given to the present embodiment. Specific conditions for proper fitting (for example, the size of the clearance) are given to the automatic control circuit 21. Cylindrical member 1 used as a reference
7a is conveyed to the outer diameter dimension measuring device 19 as indicated by an arrow g, and the output signal h representing the measured value is input to the automatic control circuit 21. The measured cylindrical member 17b is conveyed to and accommodated in the compatible pallet 24 as indicated by arrow i.

The cylindrical member 18a, which is the workpiece, is conveyed as indicated by the arrow k, and is gripped by the chuck 20b concentrically with the main shaft 20a. 20 is a headstock.

Reference numeral 18b denotes a workpiece (cylindrical member) which is chucked and ground. The cylindrical member in the present invention may be a bottomed cylinder or a bottomless cylinder. The grindstone shaft of the rotating grindstone 23a during grinding is attached to the grindstone shaft rotation / forward / backward drive mechanism 25 to finish the inner peripheral surface of the cylindrical member 18b by grinding.

The automatic control circuit 21 controls the grindstone shaft rotation / forward / backward drive mechanism 25 to change the inner diameter dimension and / or the taper amount of the grinding surface to the "cylindrical member 17 as a reference member".
a value that properly matches a. "

The cylindrical member 18c thus adaptively ground is transported as shown by an arrow m and stored in the adaptive pallet 24, and is carried out while keeping a pair with the measured columnar member 17b, and the next step. Sent to. In the embodiment of FIG. 2A, since the rotary grindstone 23a is inserted into a relatively thin cylindrical member (with an inner diameter of less than 10 mm) for grinding, the rotary grindstone 23a being ground is electrolyzed in the cylinder. There is no extra space to place the electrodes for dressing.
Therefore, a dressing step is provided as shown in FIG.

That is, the whetstone shaft rotation / forward / backward drive mechanism 2
Remove the rotary grindstone from No. 5, and as shown in (B), attach it to the rotating means (not shown) facing the electrode 22a provided separately from the headstock 20 and rotate it as indicated by the arrow θ. While supplying the electrolytic solution 22b, electrolytic dressing (interval dressing) is performed.

As an embodiment different from this embodiment, an electrolytic bath (not shown) may be provided for electrolytic dressing. Further, a grinding liquid can be used as the electrolytic solution.
According to the present embodiment, it is possible to grind a cylindrical member with high performance so as to properly fit with each of the mass-produced finished cylindrical members. FIG. 6 is a process diagram schematically showing a third embodiment of the present invention.

Reference numeral 5 is an ultra-high hardness abrasive grain (abbreviation: cemented carbide abrasive grain) having an average particle diameter of the order of micrometers.
Is. In this example, diamond fine powder was used,
As an embodiment different from this, CBN (cubic boron nitride) is used.
Fine powder may be used. By using such a fine powder (average particle size of the order of micrometers), the so-called grindstone has a fine mesh, and mirror finishing is possible.

Reference numeral 6 is a ceramic ultrafine grain having an average grain size smaller than that of the cemented carbide grain 5.
In the present invention, ultrafine means fineness (average particle diameter) smaller than the cemented carbide grains 5. As the material of the ceramic ultrafine particles 6, oxides, silicides, borides, nitrides, carbides,
Alternatively, at least one of the interoxide compounds is used. Desirably, a plurality of types of these materials are mixed to obtain a bond group having desired physical properties. The formulation of the formulation can be determined empirically or experimentally as appropriate.

Reference numeral 7 represents metal ultrafine particles, and the meaning of ultrafine is the same as that described for ceramic ultrafine. As the material of the metal ultrafine particles 7, a metal having an atomic number of 24 to 29, that is, Cr having an atomic number of 24,
5 Mn, 26 Fe, 27 Co, 28 N
i, or Cu of 29 is used as a main component, and one or more kinds of elemental metals or an alloy containing these metals is used. This configuration is based on the inventor's accumulation of empirical techniques over many years and the knowledge obtained by experiments for the present invention. The ultra-hard abrasive grains 5, the ceramic ultra-fine grains 6, and the metal ultra-fine grains 7 are mixed as indicated by arrows a, a ', a "(step 31), and hot-pressed as indicated by arrow b (step 31). Three
Proceeding to 2), molding (arrow c) is carried out to manufacture a cylindrical or annular whetstone body 33. Separately from the above process, base metal 30
To manufacture. In the present invention, the base metal 30 refers to a member that functions as a boss to be mounted on the rotating shaft, and does not necessarily have to be made of only metal.

Cylindrical or annular grindstone body 33 and base metal 3
0 and 0 are combined and joined as shown by arrows d and d ′ to obtain a semi-finished product 35 which is almost a finished product in appearance.

The outer peripheral surface of the main body of the grindstone constituting the semi-finished product 35 is subjected to dressing finishing such as electrolytic treatment which will be described later in detail with reference to FIGS. 12 and 13 (step 36). In FIG. 3, the average particle size of the ultrafine particles 6 and 7 is set smaller than the average particle size of the cemented carbide particles (5a # 5d).

The material of the ceramic ultrafine particles 6 is a non-electrolyte, has a high rigidity at room temperature, can be processed into ultrafine particles, is chemically stable, and is hard pressed by hot pressing. It is necessary to have a heat-welding property with respect to the metal and the metal (the metal forming the metal ultrafine particles 7).
Further, it is desirable that it is relatively inexpensive and non-toxic or low-toxic. Fine ceramics containing oxides, silicides, borides, nitrides, carbides, or interoxide compounds satisfying these various conditions may be appropriately selected and used. The material of the metal ultrafine particles 7 is conductive, ionizable,
It must be able to be processed into ultrafine particles that are solid at room temperature, be chemically stable, and have sinterability.
Further, it is desirable that it is relatively inexpensive and non-toxic or low-toxic. As a material satisfying these various conditions, "metal having atomic number 24 to atomic number 29, or alloy containing these metals" is recommended. The ceramic-metal composite bond grindstone (abbreviation Cerameta grindstone) 4 shown in FIG. 12 has cutting edges formed by protruding a part of the cemented carbide grains on the surface side (upper surface in the figure). It is desirable that recesses be formed between the hard abrasive grains. This is because this recess functions as the chip pocket described earlier with reference to FIG. The composite bond grindstone subjected to the electrolytic finishing in step 36 shown in FIG. 6 has a structure as shown in FIG. 3 and has excellent grinding performance.

In FIG. 6, the outer peripheral surface (the surface that performs the grinding action) of the cylindrical or annular grindstone body 33 formed by the hot pressing step 32 is not in the desired state as shown in FIG. The surface layer is embossed with a hot press to become a smooth surface, which is similar to FIG. That is, the protrusions of the cemented carbide grains 5a and 5b are worn away. In the state where the hot pressing (step 32) is completed, the cemented carbide grains are not yet worn away, but similar to the state of FIG. 4 in the sense that the cemented carbide grains are buried in the composite bond base and have no protrusions. is doing.

The semi-finished product 35 shown in FIG. 6 is unfinished because the outer peripheral surface thereof is similar to that of FIG. 4, that is, there is no protrusion (cutting edge) of cemented carbide grains and no chip pocket. It is in a state.

Therefore, in step 36, electrolytic dressing,
Alternatively, when a known discharge dressing or a known mechanical dressing (using a diamond tool or the like) is applied, cutting edges and chip pockets are formed as shown in FIG. Becomes

The thus-prepared composite bond grindstone is supplied as a commodity, and the end user can immediately use it to perform a grinding operation.

As the grinding work is performed, the mesh is crushed as shown in FIG. 4, but this can be electrolytically dressed to restore the grinding force as shown in FIG. 7A to 7C are schematic process diagrams showing a modification of the embodiment shown in FIG.

Next, FIG. 7 will be explained by extracting points different from FIG.

In the embodiment shown in FIG. 6, an integral cylindrical or annular grindstone body 33 is hot pressed (step 3).
2), but in the embodiment of FIG.
Grinding stone segments 37a, 37 having a shape obtained by dividing this into three
b and 37c are molded (arrow c '), and these are combined and joined to the base metal 30 so as to form a cylindrical shape (or an annular shape). The semi-finished product 35 'thus completed is shown in FIG.
Is similar to the semi-finished product 35 in the above embodiment. As the finishing step 36 of the semi-finished product 35, as in the embodiment of FIG. 6, any arbitrary means of electrolytic finishing, discharge finishing, or mechanical finishing (diamond tool) can be applied. That is, it is desirable to apply electrolytic dressing so that the work does not have to be interrupted (or to shorten the interrupt time) after the grinding operation is started using this ceramic-metal composite bond grindstone. However, the finishing process 36 in FIG. 6 and FIG.
Since it is the final stage of manufacturing, it is not necessary to consider interruption of the grinding operation, and any dressing method can be applied.

[0099]

EXAMPLES Examples of the present invention will be described below in comparison with conventional examples.

FIG. 8 is a relationship diagram between the cutting amount and the machining allowance by the conventional grindstone. In this test, a conventional resin metal bond grindstone (# 4000: average particle size 2 to 6 μm) was used to process a chromium nitride workpiece, and the cut amount and the stock removal were compared.

FIG. 8A shows a change in stock removal when the number of cuts is increased by 0.5 μm. From this figure, it can be seen that the machining allowance deviates greatly from the depth of cut when the number of grindings is 7 or more.

FIG. 8B shows a change in machining allowance when 10 pieces are continuously ground with a cutting depth of 2 μm. From this figure, it can be seen that the machining allowance is about half the cutting depth.

From the two figures of FIG. 8 described above, it is understood that in the conventional resin metal bond grindstone, the actual machining allowance is significantly smaller than the cutting amount due to the elasticity of the grindstone itself. Figure 9
FIG. 4 is a relationship diagram between a cutting amount and a machining allowance by the grindstone of the present invention. In this test, a ceramics / metal composite bond grindstone (# 2500: average particle size 5 to 10 μm) was used.
In (A), the cut amount was 2.0 μm, and in (B), the cut amount was 1.0 μm. As a result, the actual machining allowance was 1.9 μm in (A) and 1.0 μm in (B), and the result that the cutting depth and the machining allowance were accurately matched was obtained. This is because the rigidity (elastic modulus) of the grindstone according to the present invention is very high (large).
It is shown that. FIG. 10 is a comparison diagram of the straight shape of a workpiece with a grinding wheel. In this test, the diameter is about 8m
In (A), a ceramic-metal composite bonded grindstone (# 2500) of a cylindrical material having a length of 55 mm and a length of 55 mm is used.
In (B), a conventional resin / metal composite bond grindstone (# 4000) was used to grind into a cylindrical shape. The thickness of each grindstone is larger than the length of the cylindrical material, and the entire length is ground at the same time.

In the grindstone of the present invention (A), the straightness (0.15 μm) higher than that of the conventional grindstone of (B) was obtained although the abrasive grains were coarse. Therefore, it can be seen that the grindstone of the present invention is also excellent in enhancing straightness. The straightness of the conventional grindstone (B) is 0.19 μm,
Although the target of the present invention (0.5 μm or less) was sufficiently satisfied, the target could not be achieved with this grindstone due to its elasticity in diameter accuracy. FIG. 11 is a comparison diagram of the outer diameter dimensions of the present invention and the conventional grindstone by continuous grinding. In this test, (A)
Then, the ceramic-metal composite bond grindstone (#
2500: average particle size 5 to 10 μm), and in (B), a conventional resin-metal composite bond grindstone (# 4000: average particle size 2 to 6 μm) is used to continuously grind a plurality of workpieces. The changes in outer diameter dimensions were compared.

In the grindstone of the present invention (A), even if the outer diameter before grinding is different, the outer diameter after grinding is almost the same,
Regardless of the processing resistance, the rigidity (elasticity coefficient) of the grindstone
Is very high, so it can be understood that the cutting position of the grindstone can be processed accurately. On the other hand, in the conventional grindstone of (B), if the outer diameter before grinding is different, it changes greatly after grinding. That is, since the rigidity (elasticity coefficient) of the grindstone is low, it is understood that the grindstone bends due to the magnitude of the machining resistance, and the grindstone cannot be machined to the cutting position. Further, in the test of FIG. 11, the grindstone-ground work of the present invention was extremely excellent in the roundness maximum of 0.41 μm, cylindricity maximum of 0.83 μm, and straightness maximum of 0.33 μm. In addition, the processing roughness was Ra maximum 0.019 μm and Rz maximum 0.11 μm, and an excellent smooth surface that could be called a mirror surface was obtained. This sufficiently satisfies the target high accuracy of diameter tolerance ± 0.3 μm, straightness of 0.5 μm or less, roundness of 0.5 μm or less and high quality of surface roughness Rz 0.4 μm or less.

[0106]

As described above with reference to the embodiments, according to the method of claim 1, since the ultrafine ceramic particles forming the ceramic / metal bond group are not subjected to electrolysis, the ultrafine metal particles are formed. Only this elutes to form a chip pocket and has a dressing effect. The ceramic bond that remains without elution has high rigidity, which enables ultra-precision grinding finish.

When the method of claim 2 is used in combination with the method of claim 1, centerless grinding can be performed with high accuracy and high efficiency. When the method according to claim 3 is used in combination with the method according to claim 2, it is possible to grind with a very high precision so that the cylindrical member which is the workpiece is properly fitted to the finished cylindrical member. You can The method of claim 2 is particularly effective when the dimensional variation of the finished surface of the inner peripheral surface of the cylindrical member is relatively large.

According to the method of claim 4, dressing of the ceramic / metal bond grindstone is simultaneously performed while grinding the workpiece with the ceramic / metal bond grindstone, and the ceramic / metal bond grindstone is always It can be kept well dressed.

According to the method of claim 5, the rotary grindstone is dressed in a sharp state without the need for mechanical dressing, and the inner peripheral surface of the cylindrical member as the workpiece is highly efficiently and efficiently It can be ground with high precision. According to the method of the sixth aspect, the cylindrical member which is the workpiece can be ground so as to be properly fitted to the finished cylindrical member as a reference.
The method of claim 6 is suitable when the accuracy of the cylindrical member grinding means is higher than the accuracy of the cylindrical member grinding means.

According to the method of claim 7, even if the circular diameter of the cylindrical member is small and the difference from the outer diameter of the rotary grindstone is small, the rotary grindstone can be electrolytically dressed.
According to the method of claim 8, it is possible to perform grinding by using electrolytic dressing when necessary (during finishing or mirror finishing). Further, this electrolytic dressing can be performed continuously or intermittently (at intervals) in accordance with the processing step and processing quality to finely control and maintain the projection of abrasive grains. According to the apparatus of claim 9, the outer peripheral surface of the cylindrical member can be centerless ground with ultra-high dimensional accuracy and excellent surface roughness, and it is not necessary to provide a mechanical dresser.

According to the apparatus of the tenth aspect, the cylindrical member which has been finished is used as a reference so as to properly fit the cylindrical member which is the object to be processed, with high efficiency and with excellent surface roughness. In addition, it is possible to grind with extremely high dimensional accuracy.

According to the apparatus of claim 11, while performing the grinding work of the cylindrical member by the centerless grinding machine, at the same time, the grinding wheels are dressed in parallel, and the surface condition of the grinding wheels is always kept good. can do.
Therefore, it is not necessary to interrupt the grinding work and perform dressing, and the grinding process can be performed with higher efficiency. According to the apparatus of claim 12, since the rotary grindstone is composed of a ceramic / metal bond grindstone, good sharpness can be obtained by electrolytically dressing the grindstone.
Moreover, since the rotary grindstone has high rigidity in the state of being electrolytically dressed, it is possible to perform ultra-precision grinding finish.

According to the apparatus of the thirteenth aspect, the inner peripheral surface of the cylindrical member, which is the object to be processed, is ground so as to be fitted properly with the cylindrical member, which is the workpiece, with the finished cylindrical member as a reference. Can be done.

Even if the inner diameter of the cylindrical member is small and the spare space is small when the rotary grindstone is inserted, the rotary grindstone can be electrolytically dressed, so that the sharpness of the rotary grindstone is improved. Can be maintained. Claim 1
According to the apparatus of No. 4, the electrolytic dressing apparatus can be used to grind when necessary (during finishing or mirror finishing). In addition, this electrolytic dressing device can be continuously or intermittently (at intervals) depending on the processing process and processing quality.
Therefore, it is possible to finely control and maintain the projection of the abrasive grains.
Further, according to the method of claim 15, since the cemented carbide grains (5) are fine grains of the order of micrometers, a bond grindstone capable of grinding and finishing a good mirror surface in a dressed state is constituted.

In addition, the bond group is composed of a mixture of "ceramic ultrafine particles of high rigidity and non-electrolyte (6)" and "electroconductive and electrolytically removable ultrafine particles of metal (7)". Since the surface layer is made porous to form the chip pocket in the electrolytically dressed state, sharpness is good, and the rigidity is high in the dressed state, and ultra-high precision grinding is possible. According to the method of claim 16, the chromium of atomic number 24, the manganese of 25, the iron of 26, the cobalt of 27, the nickel of 28 and the copper of 29 are solid at room temperature, non-toxic and easy to handle, Moreover, it has an affinity for the cemented carbide grains (5) and ceramics (6) and is suitable for sintering (hot pressing). In addition, any of them can be anodized into metal ions, so that electrolytic dressing is possible. Moreover, these metals are mass produced and relatively inexpensive.

According to the method of the seventeenth aspect, the fine ceramic bond material made of these compounds has an affinity for the cemented carbide grains and the metal grains. That is,
These materials are used as a binder because they have a bondability to the cemented carbide grains (5) and metal grains (7) in a partially heat-softened state and have sufficient rigidity near room temperature. The grindstone has high rigidity and is suitable for ultra-high precision grinding. According to the method of claim 18, a grindstone body (33).
Since the hot press molding and the preparation of the base metal (30) are separately performed and then the two are joined, the fine ceramic forming the grindstone body (33) and the base metal (30) are formed. There is no risk of cracking due to the difference in coefficient of thermal expansion from the steel material, and for the same reason, residual stress does not occur in the product, so a highly reliable grinding wheel can be obtained.

According to the method of claim 19, the outer peripheral surface of the cylindrical or annular grindstone body constructed by applying claim 18 is smoothed by hot press molding.
By dressing, the product is prepared to have a cutting edge and a chip pocket, and the product is ready for use immediately. In the composite bond grindstone according to the invention of claim 20, since the bond group is formed by the ceramic ultrafine particles (6) and the metal ultrafine particles (7), the metal ultrafine particles can be obtained by electrolyzing the bond group. (7) is selectively electrolytically removed to form a chip pocket corresponding to the size of ultrafine particles, and the sharpness (grinding performance) of the grindstone is improved. In addition, the ultrafine particles (6, 7) remaining without being electrolyzed form a structure bridging with each other and exhibit high rigidity. Therefore, ultra-high precision grinding is possible.

According to the twenty-first aspect of the invention, the metal material forming the ultrafine metal particles (7) is solid at room temperature, has the physical properties of being sintered by hot pressing, and is nontoxic. It is easy and moreover, it is chemically stable and it is easy to guarantee the quality retention. Moreover, since these metal materials are industrially mass-produced and supplied, they can be obtained inexpensively and stably. According to the invention of claim 22, the melting point, sintering temperature, coefficient of thermal expansion, ductility, malleability, hardness, It is possible to change the toughness and other physical properties, and moreover, it is possible to control the change in the physical properties by adjusting the addition amount of the above other substances.
Desired physical properties can be given to the bond group, and in particular, crack generation due to hot pressing can be prevented.

According to the twenty-third aspect of the invention, since the non-metallic material forming the ceramic ultrafine particles (6) is an electrical insulating material and is not ionized, it does not elute even when subjected to electrolytic treatment, and the electrolytic treatment After that, the ultrafine particles are bridged with each other to exhibit high rigidity, and further, they have heat-welding property with respect to the cemented carbide grains, and the spillage of the cemented carbide grains is unlikely to occur, resulting in durability. Are better. According to the twenty-fourth aspect of the present invention, since the bond grindstone is formed separately from the base metal (30), there is no possibility of cracking due to the difference in thermal expansion from the base metal during hot pressing. In addition, it is possible to reduce the manufacturing cost by forming the bond grindstone main body portion, which is relatively expensive to manufacture, into a thin wall.

According to the twenty-fifth aspect of the present invention, since a part of the ultrafine grains in the surface layer portion of the main body or segment of the bond grindstone hot pressed during the manufacturing process is removed, the cemented carbide is relatively hardened. A part of the particles protrudes from the surface layer to form a cutting edge, and the recess formed by the removal functions as a chip pocket, and a desired grinding performance (sharpness) is provided.

That is, by applying claim 25 to the composite bond grindstone according to the invention of claim 24,
It can be completed as a product if the "obtained end user can immediately use it". Therefore, the precision grinding method and apparatus of the present invention, the composite bond grindstone used for the same, and the manufacturing method thereof have a high rigidity (elastic coefficient) of the bond base material, and are capable of ultra-high precision grinding.
Not only the protrusion of the cemented carbide grains is formed by the electrolytic dressing, but also the chip pocket is stably formed, and excellent sharpness (grinding performance) can be maintained for a long time, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic conceptual diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic conceptual view showing a second embodiment of the present invention.

FIG. 3 is an enlarged sectional view schematically showing a desirable state of the ceramic / metal composite bond grindstone used in the present invention.

FIG. 4 is an enlarged cross-sectional view schematically showing a worn state of the ceramic-metal composite bond grindstone shown in FIG.

5 is an enlarged cross-sectional view of a state after electrolytically dressing the worn ceramic metal as shown in FIG.

FIG. 6 is a process diagram schematically showing an embodiment of a method for manufacturing a composite bond grindstone according to the present invention.

FIG. 7 is a schematic process diagram showing a modification of FIG.

FIG. 8 is a diagram showing a relationship between a cutting amount and a machining allowance by a conventional grindstone.

FIG. 9 is a relationship diagram between a cutting amount and a machining allowance by the grindstone of the present invention.

FIG. 10 is a comparative view of a straight shape of a workpiece with a grinding wheel.

FIG. 11 is a comparison diagram of the outer diameter dimension of the present invention and the conventional grindstone by continuous grinding.

FIG. 12 is a schematic view of a conventional grindstone using cemented carbide grains, in which (A) shows a normal state and (B) shows a clogging state.

13A and 13B are schematic views of the conventional grindstone shown in FIG. 12, in which FIG. 13C shows a blinded state, and FIG. 13D shows a blinded state.

FIG. 14 is a process diagram of a known ELID (electrolytic in-process dressing).

[Explanation of symbols]

1a Carbide Abrasive Grain, 1b Bonding Agent, 1c Pore, 1d Chip Pocket, 1e Wear Abrasive Grain, 1f Drop Abrasive Grain, 2
Workpiece (work), 3 chips, 4 Ceramet grinding wheel, 5a, 5a # 5e cemented carbide grain, 6 ceramic ultrafine grain, 7 metal ultrafine grain, 8 centerless grinder, 8a
Lower slide, 8b Horizontal turning plate, 8c Upper slide, 8d Grinding liquid nozzle, 9 blade, 10 adjusting grindstone, 11a # 11c Cylindrical member, 13 Electrode member, 1
4a # 14b Cylindrical member, 15 Inner diameter measuring device, 16
Automatic control circuit, 17a # 17b Cylindrical member, 18a # 1
8c Cylindrical member, 19 Outer diameter measuring instrument, 20 Headstock, 20a Spindle, 22a Electrode, 22b Electrolyte, 2
3a # 23b Rotary grindstone, 24 Compatible pallet, 25
Grindstone axis rotation / forward / backward drive mechanism, 26 bond base, 27
Oxide film, 30 base metal, 31 mix, 32 hot press, 33 grindstone body, 35, 35 'semi-finished product, 36 next process (finishing process), 37a # 37c grindstone segment

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B24D 3/02 B24D 3/02 A 310 310A (71) Applicant 000227445 Nietrex Headquarters Co., Ltd. Taketoyo Chita-gun, Aichi Prefecture No. 184 (72), inventor Osamu Omori, 2-1, Hirosawa, Wako-shi, Saitama, RIKEN (72) Inventor, Kenichi Yoshikawa, 3-17 Kandanishikicho, Chiyoda-ku, Tokyo Hirose Building, 9th floor, New Generation Processing System Incorporated (72) Inventor Toru Tachibana 2 Mikron Precision Co., Ltd. at 578 Zao Ueno, Yamagata City Yamagata Prefecture (72) Inventor Tomihiko Hazumi 2 Mikron Precision Co., Ltd. at 578 Zao Ueno, Yamagata City, Yamagata Prefecture ( 72) Inventor Chikamura Murakoshi 2 Mikron Precision Co., Ltd., 578, Zao Ueno, Yamagata City, Yamagata Prefecture (72) Inventor Mitsuhiro Hasegawa Aichi 184, Koyo, Taketoyo-cho, Chita-gun, Nietrex Headquarters, Inc. (72) Inventor, Kiyoshi Narita 184, Koei-cho, Taketoyo-cho, Chita-gun, Aichi (72) Inventor, Go Shibata, Chita-gun, Aichi Taketoyocho Koyo No. 184 F-Term of Nietrex Headquarters Co., Ltd. (reference) 3C034 AA01 AA05 BB91 CA02 CB01 DD01 DD09 3C043 AA08 AB07 CC03 CC11 DD06 3C047 AA25 3C063 AA02 AB03 BB02 BC02 BC05 BC08 BD01 BG10 FF20 FF23FF23

Claims (25)

[Claims] 1. A cemented carbide grain having an average grain size of a micrometer order in advance, and a ceramic ultrafine grain having an average grain size smaller than that of the cemented carbide grain.
A grinding wheel (4) is constituted by a ceramic-metal composite bond wheel formed by mixing ultra fine particles of a metal having an average particle diameter substantially equal to that of the ceramic ultra fine particles and hot pressing the mixture. If a part of the cemented carbide abrasive grains is projected from the surface of the ceramic-metal composite bond grindstone in a state in which it is enlarged, and at least the metal ultrafine particles near the surface of the ceramic-metal composite bond grindstone A precision grinding method characterized in that a part is electrolytically removed, a chip pocket is formed in the recess after the removal, and the workpiece is ground by this grinding wheel. 2. The grinding wheel (4), which is a grinding wheel, is rotated while the cylindrical work piece (11b) is supported and rotated by an adjusting grindstone (10) and a blade (9). 2. The precision grinding method according to claim 1, wherein centerless grinding is performed by contacting a work piece. 3. A given finished cylindrical member (14a) is used as a reference, and the outer periphery of an unfinished cylindrical member (11a) is ground so as to be fitted properly thereto. The inner diameter of the finished cylindrical member is measured, and based on the measured value, the cylindrical member (11
The target value of the finishing dimension of a) is calculated, and at least one of the lower slide (8a) and the horizontal turning disk (8b) of the centerless grinding machine (8) is adjusted based on the target value of the finishing dimension to form a cylindrical member. A cylindrical member (14b) whose outer peripheral surface has been ground and whose inner diameter has been measured,
The precision grinding method according to claim 1 or 2, wherein the ground cylindrical member (11c) is paired, and the pair is held and delivered to the next step. 4. While rotating a grinding wheel (4) composed of the ceramic-metal composite bond wheel,
While the outer peripheral surface of the cylindrical member, which is the workpiece, is being ground, in the region where the outer peripheral surface of the grinding wheel is not in contact with the workpiece (11b), the electrode member (1
3) are arranged facing each other with a gap, and a conductive grinding liquid is supplied to the gap between the grinding wheel and the electrode member, and a positive voltage is applied to the grinding wheel, and a negative voltage is applied to the electrode member. The precision grinding method according to claim 3, wherein the ultrafine particles of metal are electrolytically removed by applying each. 5. A cylindrical member (18b) which is a workpiece is chucked concentrically with respect to a spindle (20a) of a headstock (20) and mounted on a grindstone shaft rotation / forward / backward drive mechanism (25). In the method of grinding the inner peripheral surface of the cylindrical member with a rotating grindstone (23a), in advance, a cemented carbide grain having an average grain size of a micrometer order and an average grain size of the cemented carbide grain A ceramic obtained by mixing ultra fine grains of ceramic having a small average grain size and ultra fine grains of metal having an average grain size substantially equal to those of the cemented carbide abrasive grains, and performing hot press molding. With the metal composite bond grindstone, the rotary grindstone (23
a), which is a state in which a portion of the cemented carbide abrasive grains protrude from the surface of the ceramic-metal composite bond grindstone in a microscopically enlarged state, and near the surface of the ceramic-metal composite bond grindstone Precision removing method, characterized in that at least a part of the ultrafine metal particles is electrolytically removed, a chip pocket is formed in the recess after the removal, and the inner peripheral surface of the cylindrical member is ground by this rotating grindstone. . 6. An inner circumference of an unfinished cylindrical member (18a) is ground so as to be fitted properly with respect to a given finished cylindrical member (17a) as a reference. The outer diameter of the finished cylindrical member is measured, and the cylindrical member (18) is measured based on the measured value.
The target finish dimension of a) is calculated, and the whetstone shaft rotation / forward / backward drive mechanism (25) is adjusted based on the target target finish dimension, and the inner peripheral surface of the cylindrical member is rotated by the whetstone (23a). A cylindrical member (17b) that has been ground by
The precision grinding method according to claim 5, wherein the ground cylindrical member (18c) is paired, and the pair is held and delivered to the next step. 7. If the surface condition of the rotary grindstone deteriorates as a result of grinding the inner peripheral surface of the cylindrical member with the rotary grindstone (23a), the grinding operation is temporarily interrupted to drive the rotary grindstone. Removed from the mechanism (25), the rotary grindstone was positioned facing the electrode (22a) with a gap, and a positive voltage was applied to the rotary grindstone while the electrolytic solution was interposed in the gap. 7. The precision grinding method according to claim 6, wherein a negative voltage is applied to electrolytically remove the ultrafine metal particles. 8. The electrolytic removal is performed using an electrolytic dressing, the electrolytic dressing is ground without electrolysis at the time of rough processing, and at the time of finish processing or mirror surface processing,
2. The precision grinding method according to claim 1, wherein electrolysis is continuously or intermittently applied according to a processing step and processing quality to finely control and maintain the protrusion of abrasive grains. 9. An adjusting grindstone (10) mounted on a bed (12) via a lower slide (8a) and a horizontal turning disk (8b), and a workpiece to be worked together with the adjusting grindstone. Cylindrical member (1
A centerless grinder having a blade (9) for supporting 1b) and a grinding wheel (4) which is a grinding wheel for contacting and grinding the columnar member, wherein the grinding wheel (4) is a micrometer. A mixture of fine cemented carbide grains which are fine particles, ceramic ultrafine grains smaller than the average grain size of the cemented carbide grains, and metal fine grains having an average grain size substantially equal to the ceramic fine grains. Is a ceramic-metal bond grindstone formed by hot press molding, and the ceramic-metal composite bond grindstone has a part of cemented carbide grains protruding from the surface thereof. At least a part of the ultrafine metal particles in the vicinity of the surface is electrolytically removed, and the recesses after the removal form chip pockets. 10. A cylindrical member (11) which is the workpiece.
a) is to be ground so that the finished cylindrical member (14a) is properly fitted to the cylindrical member (14a), and the inner diameter measurement for measuring the inner diameter of the cylindrical member. Bowl (1
5) and an automatic control circuit (16) for inputting an output signal of the inner diameter measuring device and controlling the lower slide (8a) and / or the horizontal turning disk (8b) of the centerless grinding machine (8). The precision grinding device according to claim 9, wherein 11. An electrode member (13), which is installed facing the outer peripheral surface of the grinding wheel (4) with a gap, and a grinding liquid nozzle for supplying a grinding liquid to the gap between the electrode member and the grinding wheel. The precision grinding apparatus according to claim 7 or 10, further comprising (8d) and an application unit that applies a negative voltage to the electrode member and a positive voltage to the grinding wheel. 12. A headstock (20) having a chuck means (20b) for chucking a cylindrical member (18b) and a spindle (20a) to which the chuck is mounted, and having an inner diameter dimension of the cylindrical member. Inner circumference provided with a rotary grindstone (23a) having an outer diameter smaller than that of the above, and a grindstone shaft rotation / forward / backward drive mechanism (25) for mounting the rotary grindstone and rotating the grindstone and moving the shaft back and forth. In the surface grinder, the rotary grindstone (23a) is composed of a cemented carbide grain which is a micrometer-order fine grain, a ceramic ultrafine grain smaller than the average grain size of the cemented carbide grain, and the ceramic ultrafine grain. Mixing with ultrafine metal particles with equal mean particle size,
It is a ceramic-metal bond grindstone formed by hot press molding, and the ceramic-metal bond grindstone has a portion of the cemented carbide grains protruding from its surface and A precision grinding machine characterized in that at least a part of the ultrafine metal particles is electrolytically removed, and the recesses after the removal form chip pockets. 13. A cylindrical member (18) which is the workpiece.
a, 18b) are cylindrical members (17
An outer diameter dimension measuring device (19) for measuring the outer diameter dimension of the finish-processed cylindrical member, which is to be ground so as to be fitted properly with respect to a), and An automatic control circuit (21) for controlling the grindstone shaft rotation / forward / backward drive mechanism (25) in accordance with the output signal of the outer diameter dimension measuring device, and is attached to the grindstone shaft rotation / forward / backward drive mechanism. Supporting means for rotatably supporting by removing the rotary grindstone,
And a rotating grindstone (23b) rotatably supported
An electrode (22a) installed opposite to and with a gap, a power supply for applying a positive voltage to the rotating grindstone and a negative voltage to the electrode, and an electrolytic solution in the gap between the rotating grindstone and the electrode. 13. The precision grinding device according to claim 12, further comprising an electrolytic solution supply means for supplying (22b). 14. An electrolytic dressing device for performing the electrolytic removal is provided, and by the electrolytic dressing device, grinding is performed without applying electrolysis at the time of roughing, and depending on a processing step or processing quality at the time of finishing or mirror finishing. The precision grinding apparatus according to claim 9 or 11, wherein electrolysis is continuously or intermittently applied to finely control and maintain the projection of the abrasive grains. 15. A method for producing a bond grindstone in which cemented carbide particles are dispersed in a bond base, comprising a fine cemented carbide grain (5) having an average particle size of the order of micrometers and an average particle size of Ceramic ultrafine particles (6) smaller than the average particle size of the cemented carbide grains and metal ultrafine particles (7) having an average grain size smaller than the average particle size of the cemented carbide grains are mixed, A method for producing a composite bond grindstone, characterized by solidifying by hot pressing and molding. 16. The ultrafine particles of a metal material mainly composed of a metal element having an atomic number of 24 to 29 are used as the metal ultrafine particles (6).
5. The method for manufacturing the composite bond grindstone described in 5. 17. The ceramic ultrafine particles (6) are used by mixing at least one of oxides, silicides, borides, nitrides, carbides or interoxides, preferably a plurality of them. The method for producing a composite bond grindstone according to claim 13 or 16, characterized in that. 18. A base metal (30) for a grinding wheel when the cemented carbide particles (5), the ceramic ultrafine particles (6) and the metal ultrafine particles (7) are mixed and solidified by hot pressing. ) Is molded into a cylindrical or annular whetstone body (33) without insert molding,
Alternatively, grindstone segments (37a, 37
b, 37c) is formed, and a base metal (30) is formed separately from the whetstone body or whetstone segment so as to be fitted thereto, and the whetstone body or whetstone segment is joined to the base metal, A method for manufacturing a composite bond grindstone according to any one of claims 13 to 17, which constitutes a grindstone assembly for grinding. 19. The cylindrical or annular grindstone body (33) is formed by hot pressing, and then the electrode member is positioned with a gap facing the outer peripheral surface of the grindstone body, and the gap between the two is formed. With the electrolyte filled in, the positive voltage is applied to the grindstone main body and the negative voltage is applied to the electrode member respectively to selectively select only the ultrafine metal particles (7) located on the surface layer of the outer peripheral surface of the grindstone main body. By removing, thereby forming the chip pocket (1d) by the recess after the ultrafine metal particles have disappeared, a part of the cemented carbide particles (5) remaining without being removed is left on the surface of the bond base. The method for producing a composite bond grindstone according to claim 18, wherein a cutting edge is formed by projecting from the grindstone to impart grinding performance as a grindstone. 20. A bond grindstone in which cemented carbide grains (5) are dispersed in a bond group, wherein the cemented carbide grains are fine particles with an average grain size of the order of micrometers, and the bond group is a ceramic. Are formed by mixing the ultrafine particles (6) and the ultrafine particles of metal (7), and the average particle size of these ultrafine particles is smaller than the average particle size of the cemented carbide abrasive grains. A composite bond grindstone. 21. The metal ultrafine particles (7) are metal elements of atomic number 24 to atomic number 29, that is, any one of chromium, manganese, iron, cobalt, nickel and copper, or 21. The composite bond grindstone according to claim 20, which is mainly composed of a plurality of metal materials. 22. The metal ultrafine particles (7) include ultrafine particles made of a single metal material of any one of chrome, manganese, iron, cobalt, nickel and copper, or chrome, manganese, iron, 22. The composite bond grindstone according to claim 21, comprising an alloy material of at least one of cobalt, nickel and copper. 23. The ceramic ultrafine particles (6) are fine ceramics containing at least one of oxide, silicide, boride, nitride, carbide or interoxide compound. The composite bond grindstone according to claim 20. 24. The bond grindstone has a base metal (30) functioning as a boss for mounting on a rotary shaft at the center thereof, and a cemented carbide abrasive grain (5) at the outer peripheral part of the bond base. And a whetstone main body (33) or whetstone segments (37a, 3a) that are dispersed in a cylindrical shape or are formed in an annular shape.
7b, 37c) and a separately formed base metal, and the grindstone main body or the grindstone segment are joined to each other. Composite bond grindstone. 25. The cylindrical or annular grindstone body (33) or grindstone segments (37a, 37b, 37).
At least a part of the metal ultrafine particles (7) constituting the bond base are removed on the surface layer portion of the surface of c) that functions as a grinding wheel, and the removed traces form ultrafine recesses. The composite bond grindstone according to claim 24, which is formed.