JP2003251568A - Grinding wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinding wheel which can effectively perform the dressing of grindstones. <P>SOLUTION: A plurality of grindstone chips 46 are disposed in a substantially continuous manner on one side surface of a disk-like base plate 40 along a circumferential edge part thereof, and a dressing member 48 to feed free abrasive grains to a surface to be ground is provided on an inner side of the grindstone chips. The dressing member 48 is constituted of a formed body which holds abrasive grains by a binder consisting of aqueous polyurethane resin so that resin solids are contained at the rate of 0.3 to 5 pts.wt. based on 100 pts.wt. of abrasive grains. <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 grinding wheel used for a surface grinder, a polishing device, and the like, and more particularly to a grinding wheel having a self-dressing function (self-dressing function). .

[0002]

2. Description of the Related Art Conventionally, a grinding wheel in which a grindstone (referred to as a superabrasive grindstone) containing superabrasive grains such as diamond and cubic boron nitride (CBN) is fixed to a disk-shaped base is generally known.

In a grinding wheel, when the grinding wheel is clogged or crushed, the grinding function is significantly deteriorated. Therefore, in order to maintain the grinding function, dressing of the grindstone is required as needed. Therefore, for example, in Japanese Patent Laid-Open No. 61-226260, A abrasive grains (abrasive grains containing alumina oxide (Al ₂ O ₃ ) as a main component) and C abrasive grains (silicon carbide (SiC) as a main component) are used. A grinding machine is proposed that is capable of dressing a whetstone during work by supplying a dressing liquid containing free abrasive grains such as (abrasive grains) etc. between the whetstone and a workpiece as needed. .

According to this grinder, a large amount of loose abrasive grains can be supplied to the grindstone during processing, which is effective for dressing the grindstone. However, there is a drawback in that the equipment for supplying the dressing liquid to the grinding machine in addition to the grinding liquid is required, which contributes to increase in size and cost of the apparatus.

Therefore, as a simpler configuration, for example, in Japanese Patent Laid-Open No. 2000-42930, a grindstone containing general abrasive grains such as A abrasive grains (general abrasive grain grindstone) and a superabrasive grain grindstone are alternately arranged in the circumferential direction. Self-dressing function (self-dressing function) that allows the super-abrasive grindstones to be dressed by arranging them and removing them from the general abrasive grindstones during processing (free abrasive grains)
A grinding wheel equipped with is proposed.

[0006]

However, since the loose abrasive grains are carried to the outside by the centrifugal force generated by the rotation of the grinding wheel,
With the configuration of the grinding wheel as described above, almost no dressing effect can be expected in the portion of the superabrasive grinding wheel near the center of the grinding wheel. In addition, the amount of loose abrasive grains generated during processing is not always sufficient to satisfy the dressing effect, and
As described above, since the general-abrasive whetstones and the superabrasive whetstones are alternately arranged in the circumferential direction, the free-abrasive grains dropped from the whetstone do not contribute to the dressing of the superabrasive whetstone by the centrifugal force. Many free abrasive grains are carried to the outside of the car, and consequently, the grinding wheel of Japanese Patent Laid-Open No. 2000-42930 could not satisfy the required dressing function.

The present invention has been made in view of the above problems, and has a self-dressing function (self-dressing function).
It is an object of the present invention to provide a grindstone wheel that is capable of dressing the grindstone more effectively.

[0008]

In order to solve the above problems, the present invention comprises a base member having a grindstone mounting surface, and a grindstone mounted on the grindstone mounting surface of the base member. In a grinding wheel that is driven to rotate about an axis in a direction substantially orthogonal to the surface on which the grindstone is disposed, the grindstone is provided so as to surround the center of rotation of the base member, and a region inside the grindstone in the radial direction of rotation. Further, a dressing member for holding the abrasive grains and dropping the abrasive grains by contact with the workpiece is provided (Claim 1).

According to this structure, the abrasive grains fall off from the dressing member during processing, and the abrasive grains (free abrasive grains) are carried to the grindstone portion, whereby dressing of the grindstone is performed. At this time, since the dressing member is provided in the region on the inner side in the radial direction of rotation of the grindstone as described above, the loose abrasive grains are uniformly supplied to the entire grindstone surface by the centrifugal force, whereby the entire grindstone is uniformly distributed. Dressed.

In the claims, "the grindstone is provided so as to surround the center of rotation of the base member" means that when the grindstone is continuously provided on the entire circumference of the substrate, a small piece is provided. The case where a plurality of whetstones in a shape of a circle are provided in a row includes the case where a plurality of whetstones are provided intermittently.

In this structure, it is preferable that the surface of the dressing member facing the workpiece be substantially flush with the grindstone surface of the grindstone (claim 2).

According to this structure, both the grindstone and the dressing member can be slid with respect to the workpiece from the beginning of use of the grindstone wheel. Therefore, while the grinding by the grindstone is favorably performed, the dressing effect on the grindstone is also favorably exhibited.

The dressing member is made of abrasive grains 10.
It is preferable that the molded product has abrasive grains held by a binder having a resin component so that the resin solid component is contained in a proportion of 0.3 to 5 parts by weight with respect to 0 part by weight (claim) Item 4).

With such a structure of the dressing member, it is possible to hold as many abrasive grains as possible in the grinding wheel during processing, in a state where they can be easily removed. That is, when the binder is less than 0.3 parts by weight in terms of the resin solid component, the regularity of the dressing member is not retained, and it becomes difficult to retain the abrasive grains in the grinding wheel.
This is because if the binder exceeds 5 parts by weight in terms of resin solid component conversion, it becomes difficult for the abrasive grains to fall off. Therefore, it becomes possible to effectively dress the grindstone while supplying as many free abrasive grains to the grindstone as possible.

In the molded article for dressing, the binder is preferably a thermosetting water-based resin (Claim 4), and preferably a water-based urethane resin (Claim 5).

According to the dressing member using such a resin as a binder, the resin component can be uniformly dispersed, and particularly the water-based urethane resin has excellent adhesion to the abrasive grains. A dressing member having the above characteristics can be satisfactorily obtained.

Further, in the grinding or polishing work, the work is usually performed while supplying the grinding liquid or the polishing liquid to the surface of the workpiece, but in the above grinding wheel, such a working liquid is supplied. It is preferable to provide the supply port at the center of rotation (claim 6).

According to this structure, since the supplied working liquid is carried to the outside by the centrifugal force, the abrasive particles can be dropped from the dressing member by utilizing the pressure. Therefore, the supply of loose abrasive grains to the grindstone can be promoted.

Further, it is preferable that the grindstone is provided with a protective layer made of resin on a side surface portion so as to surround the grindstone surface from the outside (claim 7).

According to this structure, it is possible to avoid troubles such as when the grindstone and the workpiece directly collide with each other when the grinding wheel comes into contact with the workpiece, the workpiece is damaged, or the grindstone is lost. Become.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows a grinding apparatus to which a grinding wheel according to the present invention is applied. In this figure, reference numeral 10
Shows the head of the grinding machine. This head 10
Is connected to a moving mechanism (not shown) and is fixed in a horizontal direction with respect to a workpiece fixed on a support, specifically, a workpiece W made of a hard and brittle material (for example, ceramic, stone or glass). Also, it is provided so as to be movable in the vertical direction.

The head 10 is provided with a drive shaft 12 perpendicular to the lower end thereof. The drive shaft 12 is connected to a motor (not shown) mounted in the head 10 via a speed reduction mechanism and the like, and is configured to be rotationally driven by the operation of the motor. In addition, on the outside of the drive shaft 12,
As shown in the figure, the cover 22 is provided in close contact with the drive shaft 1 with respect to the cover 22 during driving.
The two are configured to rotate relatively while slidingly contacting each other.

An assembly portion 14 of the grinding wheel 40 is integrally provided at the lower end of the drive shaft 12, and the grinding wheel 40 is assembled and fixed to the assembly portion 14 via a stepped columnar holder 30. Has been done.

The grinding wheel 40 is a grinding wheel for roughly and mediumly grinding the workpiece W, and as shown in FIG. 2 and FIG. 2, a disk-shaped substrate 42 (with a central opening 50). The grindstone tip 46 is provided on one surface (grindstone disposition surface) of the base member
And a dressing member 48, which is fixed to the lower end portion of the holder 30 with the grindstone tip 46 and the like facing downward, and is driven by the drive shaft 12 so that its central axis (reference numeral O in the drawing indicates It is designed to be driven to rotate around.

Assembling the grinding wheel 40 to the drive shaft 12 is performed with the grinding wheel 40 screwed onto the lower end of the holder 30 from the opposite side (upper side in FIG. 1) of the holder 30 to the grinding wheel 40. By being fitted together, the grinding wheel 40 is pulled in and fixed to the lower end of the holder 30,
Further, the hook 3 provided on the upper portion of the holder 30.
4 is inserted and locked in the locking hole 16 of the assembling portion 14. The locking hole 16 has a central axis O
Concentric with the dovetail groove with a slight arc in the direction of rotation.

The structure of the grinding wheel 40 will be described in more detail. The grinding wheel 40 has the disk-shaped substrate 4 as described above.
2, the plurality of the grindstone chips 46 are fixed in a row along the peripheral edge of the substrate 42 in a substantially continuous state at a minute interval, and the inside of these grindstone chips 46 (the grindstone A plurality of the dressing members 48 are fixed between the chip 46 and the opening 50).

Each grindstone tip 46 is for machining the workpiece W, and has, for example, a columnar metal bond grindstone 46a (hereinafter abbreviated as grindstone 46a) containing superabrasive grains (diamond in this embodiment) of grain size # 50. Then, this is fixed to the chip support base 46c with an epoxy adhesive, and a protective layer 46b made of epoxy resin is formed around the grindstone 46a so as to surround the grindstone surface. Then, the grindstone chip 46 is fixed to the substrate 42 by adhering the chip support base 46 c to the substrate 42.

On the other hand, each dressing member 48 is a molded body that holds dressing abrasive grains for dressing the grindstone 46a during processing. This dressing member 4
8 is a brittle molded body in which abrasive grains are bonded with a binder at an extremely low degree of bonding, and more specifically, a resin solid component is contained in a ratio of 1.5 parts by weight to 100 parts by weight of the abrasive grains. As described above, a molded body in which C abrasive grains having a grain size of # 60 (GC; green silicon carbide abrasive grains in this embodiment) is held by a binder made of an aqueous polyurethane resin is preferable. The compact has a regularity, and is configured so that the abrasive grains can be easily removed by contact with the workpiece W.

In this embodiment, four dressing members 48 are provided, and each dressing member 48 is shown in FIG.
As shown in FIG. 3, each is formed into a fan-shaped plate shape, and is bonded and fixed to the substrate 42 in a state of being evenly arranged around the opening 50 around the opening 50.

The grindstone surface of each grindstone tip 46 (the lower surface in FIG. 1) and the lower surface of each dressing member 48 are provided substantially flush with each other, and when the grindstone wheel 40 is brought into contact with the workpiece W, each grindstone chip is provided. 46 grinding wheel surfaces and each dressing member 4
The lower surface of 8 can be brought into contact with the workpiece W without a gap.

The head 10 further includes the drive shaft 12
Grinding water (processing liquid) can be supplied to the workpiece W through the inside of the above.

That is, a passage 18 extending in the axial direction and opening downward is formed at the center of the drive shaft 12, and a groove 20 is formed on the outer peripheral surface of the drive shaft 12 over the entire circumference thereof.
Is formed, and the groove 20 and the passage 18 form a communication passage 21.
Connected via Further, the grinding water supply port 2 is provided in a portion of the cover 22 corresponding to the groove 20.
4, a supply pipe 26 leading to a grinding water supply source (not shown)
Is connected to the supply port 24. When the through hole 36 is formed on the central axis of the holder 30 and the grinding wheel 40 is assembled to the drive shaft 12, the passage 18 of the drive shaft 12 and the opening 50 of the grinding wheel 40 are assembled as shown in FIG. Are connected to each other through the through hole 36 of the holder 30, whereby the supply pipe 26 and the supply port 2 are connected.
4, while the grinding water is introduced into the drive shaft 12 through the groove 20 and the communication passage 21, the passage 18 and the through hole 3
It is configured to be jetted from the opening portion 50 of the grinding wheel 40 to the processing surface of the workpiece W through 6.

Next, the function and effect of the grinding apparatus constructed as above will be described.

In order to grind the workpiece W by the above grinding device, the grinding wheel 40 is driven to rotate by the operation of the drive shaft 12, and the grinding wheel 40 is spun from the opening 50 while jetting the grinding water. While being pressed against the surface of W, the head 10 is moved to relatively move the grinding wheel 40 and the workpiece W in the horizontal direction.

In this way, each grindstone tip 46 slides along the workpiece W with the rotation of the grinding wheel 40 and the movement of the head 10, whereby the workpiece W is ground by the grindstone 46a.
Will be ground by. In this device, since the grindstone chip 46 in which the protective layer 46b is formed around the grindstone 46a as described above is used, the grindstone wheel 4 is used.
When 0 is brought into contact with the workpiece W, the edge portion of the grindstone 46a does not directly collide with the workpiece W, which effectively prevents problems such as damage to the workpiece W or loss of the grindstone 46a. To be done.

While the workpiece W is ground by each of the grindstone tips 46 as described above, the dressing member 48 slides along the workpiece W, whereby the abrasive grains (GC) contained in the dressing member 48. Will fall off, and the loose abrasive grains will exert a dressing effect on the grindstone tip 46 (grindstone 46a). At this time, in the grinding wheel 40, since the dressing member 48 is provided with the above-described configuration and arrangement, all the grinding wheel chips 46 are dressed uniformly and effectively. .

That is, since the dressing member 48 is provided inside the grindstone tip 46 as described above, the loose abrasive grains are uniformly supplied to the grindstone surface of each grindstone tip 46 by the centrifugal force, and as a result, all the free abrasive grains are supplied. The grindstone tip 46 is dressed uniformly. Moreover, since the dressing member 48 is a brittle molded body in which the abrasive grains are bonded by a binder with an extremely low degree of bonding as described above, sliding with the workpiece W as shown in the test results described later. Abrasive grains will easily fall off due to the action of liquid pressure of grinding water or grinding water. Therefore, an extremely large amount of loose abrasive grains is supplied to the grindstone tip 46 during processing,
As a result, the dressing of the grindstone tip 46 is effectively performed. In particular, in this grinding wheel 40, since the grindstone chips 46 are provided substantially continuously on the peripheral edge of the substrate 42 and the dressing member 48 is provided inside the grindstone tips 46, almost all the loose abrasive grains that fall off from the dressing member 48. Effectively contributes to the dressing of the grindstone tip 46,
This further enhances the dressing effect.

Therefore, the workpiece W can be processed while the clogging and the crushing of the grindstone tip 46 are better eliminated.

The dressing member 48 attached to the grinding wheel 40 can be manufactured by the following manufacturing method.

First, an aqueous polyurethane resin is mixed with the abrasive grains (GC) and stirred. At this time, a solvent such as water or acetone, or a crosslinking agent (for example, an aqueous polyisocyanate crosslinking agent) may be added as necessary.

Then, the mixture is poured into a molding die, naturally dried at room temperature (25 ° C.) for 12 to 24 hours, and then heated by a hot-air circulation type heater or the like to cure the mixture. As for the heat treatment, first, preheating is performed at a temperature of 20 ° C to 100 ° C for 2 to 12 hours, and after releasing the mold, 100 ° C to 2 ° C.
Heat at a temperature of 00 ° C for 10 minutes to 12 hours.

Finally, the dressing member 48 can be obtained by subjecting the molded body to burr treatment and fine adjustment of dimensions and the like.

In this embodiment, # 60 abrasive grains (G
C) A water-based polyurethane resin was mixed with 100 parts by weight at a ratio of 1.5 parts by weight as a resin solid component conversion value, and the mixture was poured into a mold and naturally dried at room temperature (25 ° C) for 12 hours. By preheating at 50 ° C. for 4 hours, releasing the mold, and further heat-treating at 150 ° C. for 40 minutes, the abrasive grains can be easily dropped off with the contact with the workpiece as follows. A good dressing member 48 could be obtained.

The following table shows the dressing member 48 manufactured as described above and a general stone grinding wheel (blue grinding wheel).
The results of tests comparing the removal performance of the abrasive grains with (the composition of the stone for grinding stones are as described in the table below). The test of the detachment performance was performed by comparing the wear rates when the dressing member 48 and the grindstone were slid (rotated) on the workpiece under the following conditions.

・ Sliding area: 30 cm ²・ Processing object: Black granite ・ Rotating speed: 400 rpm ・ Load: 30 kgf ・ Grinding fluid; Water

[0047]

[Table 1]

As shown in this table, the dressing member 48 has a significantly higher wear rate than a general grindstone (blue grindstone), and the detachment of abrasive grains in the dressing member 48 is much higher than that of the grindstone (blue grindstone). It can be considered that it is good (abrasive grains are easily separated).

By the way, the above-described grinding device is an example of a grinding device to which the grinding wheel according to the present invention is applied, and its specific configuration can be appropriately changed without departing from the gist of the present invention. For example, the following configurations can be adopted.

As shown in FIG. 3, the grinding wheel 40 may be one in which a large number of small dressing members 48 are fixed inside the grinding wheel tip 46 in a specific arrangement. When such a dressing member 48 in the form of a small piece is applied, the molding itself of the dressing member 48 is facilitated, and the productivity of the dressing member 48 is improved.

In the grinding wheel 40, as shown in FIG. 4, grinding wheels 52 are arranged along the peripheral edge of the substrate 42, and a dressing member 54 is provided on the entire portion of the grinding wheel fixing surface of the substrate 42 other than the grinding stone 52. It may be According to this grinding wheel 40, more dressing members 48 can be provided on the grinding wheel 40, so that more free abrasive grains can be supplied to the grinding wheel 52 during processing, which results in a dressing effect. Can be increased. Also,
There is also an effect that the dressing function can be continued for a longer time.

The grindstone 46 applied to the grindstone tip 46
The a is not necessarily a metal bond grindstone, and may be a grindstone such as a bidified bond grindstone or a resin bond grindstone.

The dressing member 48 of the embodiment is
The composition is such that 100 parts by weight of C abrasive grains (GC) having a particle size of # 60 contains a binder made of a water-based polyurethane resin at a ratio of 1.5 parts by weight as a resin solid component conversion value. Is not necessarily in the range of 1.5 parts by weight in terms of the resin solid component conversion, and it is sufficient that the abrasive grains can be bonded so that the abrasive grains can be easily removed by contact with the workpiece. However, in order to secure the moldability and the regularity of the dressing member 48, as shown in the following test results, it is preferable to mix the binder within the range of 0.3 to 5 parts by weight in terms of the resin solid component conversion value. preferable.

[0054]

[Table 2]

That is, when the content of the binder is less than 0.3 part by weight, the formability of the dressing member 48 becomes difficult due to lack of the resin component, and even when the dressing member 48 can be formed, its structure is too brittle. Therefore, it becomes difficult to maintain the shape. On the other hand, when the amount of the binder exceeds about 5 parts by weight, it becomes difficult to sufficiently dehumidify in the heat treatment step due to an increase in the water content, and in this case also the moldability and the regularity are impaired. Although it is not clear from this table, even if the amount of the binder exceeds 5 parts by weight, it is possible to secure moldability and regularity depending on the heat treatment method. However, in this case, the binding force of the abrasive grains becomes too strong, and the detachability of the abrasive grains (easiness of detachment of the abrasive grains) is likely to be impaired. Therefore, in order to secure formability and regularity, and to drop as many abrasive grains as possible by contact with the workpiece, C abrasive grains (GC) 10
0 parts by weight of the binder is 0.3 in terms of resin solid component conversion value
It is considered preferable to mix within the range of 5 parts by weight. This tendency is not limited to the case where the water-based polyurethane resin is used as the binder, and is the same when the binder having another resin component is used.

In an embodiment, the dressing member 48
Although the abrasive grain of grain size # 60 is used as the abrasive grain of No. 6, the grain size of the abrasive grain of the dressing member 48 is set so that the dressing function can be effectively exhibited according to the grain size of the abrasive grain contained in the grindstone 46a. It may be selected appropriately. In the case of a grinding wheel for rough / medium grinding of a workpiece W made of the above hard and brittle material (for example, ceramic, stone material, glass, etc.), generally, a grinding stone containing abrasive grains of grain size # 46 to # 400. Therefore, it is preferable that the dressing member 48 used in this type of grinding wheel contains abrasive grains having a grain size of about # 46 to # 400.

The abrasive grains and the binder contained in the dressing member 48 do not necessarily have to be the same as those in the embodiment. For example, the abrasive grains may be general abrasive grains other than GC having a grain size of # 60 (for example, A abrasive grains) or superabrasive grains such as diamond and CBN. Also, the binder
The water-based polyurethane resin does not necessarily have to be used, and other resins may be used. For example, in addition to a thermosetting resin (epoxy, phenol, etc.) such as the water-based polyurethane resin of the embodiment, a thermoplastic resin (acrylic, PVA, etc.) can be used when applicable.

[0058]

As described above, the present invention comprises a base member having a grindstone mounting surface and a grindstone mounted on the grindstone mounting surface of the base member, and is substantially the same as the grindstone mounting surface. In a grinding wheel that is rotationally driven around an axis in a direction orthogonal to each other, the grindstone is provided in an arrangement surrounding the center of rotation of the base member, and in a region on the inner side in the radial direction of rotation of the grindstone,
A dressing member that holds the abrasive grains and drops the abrasive grains by contact with the workpiece is provided, so that during the processing, the loose abrasive grains that fall off from the dressing member are uniformly supplied to the entire grindstone surface by centrifugal force. Therefore, the grindstone can be dressed extremely effectively and uniformly.

In particular, as the dressing member, the abrasive grains 10
By providing a molded body in which abrasive grains are held by a binder having a resin component such that the resin solid component is contained in a proportion of 0.3 to 5 parts by weight with respect to 0 part by weight, during processing,
It becomes possible to supply a large amount of loose abrasive grains to the grindstone, and as a result, it becomes possible to more effectively dress the grindstone.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a grinding apparatus to which a grinding wheel according to the present invention is applied.

FIG. 2 is a perspective view showing a grinding wheel according to the present invention.

FIG. 3 is a perspective view showing another example of the grinding wheel according to the present invention.

FIG. 4 is a perspective view showing another example of the grinding wheel according to the present invention.

[Explanation of symbols]

10 heads 12 drive shaft 40 grinding wheel 42 Substrate (base member) 46 grindstone tip 46a whetstone 48 Dressing material 50 opening (supply port) W workpiece

Claims (7)

[Claims] 1. A base member having a grindstone mounting surface, and a grindstone mounted on the grindstone mounting surface of the base member. The base member is rotationally driven about an axis in a direction substantially orthogonal to the grindstone mounting surface. In the grindstone wheel, the grindstone is provided so as to surround the center of rotation of the base member, and an abrasive grain is held in a region radially inward of the grindstone to contact the workpiece with the grindstone. A grinding wheel characterized in that a dressing member for dropping particles is provided. 2. The grinding wheel according to claim 1, wherein a surface of the dressing member facing the workpiece is provided substantially flush with a grinding wheel surface of the grinding wheel. 3. The grinding wheel according to claim 1 or 2, wherein the dressing member contains a resin solid component in an amount of 0.3 to 5 parts by weight with respect to 100 parts by weight of abrasive grains. A grinding wheel comprising a molded body in which abrasive grains are held by a binder having a component. 4. The grinding wheel according to claim 3, wherein the binder is a thermosetting water-based resin. 5. The dressing molding according to claim 4, wherein the thermosetting water-based resin is a water-based urethane resin. 6. The grinding wheel according to any one of claims 1 to 5, further comprising a supply port for supplying a working liquid to a rotation center. 7. The grinding wheel according to claim 1, wherein the grindstone is provided with a protective layer made of resin on a side surface portion so as to surround the grindstone surface from the outside. Whetstone wheel.