JPS6399856A - Cutting tool - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to cutting tools, particularly dental cutting tools used for cutting teeth or dental restorations, and tools for cutting other materials. It can also be used as a cutting tool.

[Conventional technology]

Dental cutting tools are generally shaped like two spheres, two cylinders, and two cones.

Hard abrasive grains such as natural or artificial diamond abrasive grains, aluminum oxide abrasive grains, or carborundum abrasive grains are fixed to the working part of the base body, which is molded into various shapes such as the shape of an axle, by electroplating or brazing. It is then installed in a dental turbine or engine and rotated at high speed, while being cooled with water injection or mist water.

Efficient cutting using such dental cutting tools is desirable for dentists and patients, but in order to do so, (1) the cutting tool must have excellent cutting ability.

■ Good discharge of cutting debris from the tooth or tooth restoration caused by cutting; ■ Elimination of heat generated by cutting between the tooth or tooth restoration and the working part of the cutting tool base. It is necessary that this is done well.

Currently, various dental cutting tools have been proposed to satisfy this condition.

That is, one having three slightly right-handed helical grooves with respect to the axis of the base working part on the outer peripheral surface of the base working part, and a symmetrical cross section as disclosed in JP-A No. 56-31744. Hexagonal Solopan bead-shaped ones stacked and grooved, or special edition 1984-
There are those having a left-handed threaded groove as disclosed in Japanese Patent No. 500280.

In the cutting tool of the first shape, the three grooves provide good cutting ability, good discharge of cutting waste, and good removal of heat, and the cutting tools of the second and third shapes have good cutting performance. It is intended to provide a good H discharge and a good heat rejection, respectively.

[Problem that the invention seeks to solve]

However, each of the cutting tools described above has the following problems.

A cutting tool having three slightly right-handed helical grooves with respect to the axis of the base working part on the outer circumferential surface of the base working part of the first shape has excellent cutting ability when the outer diameter of the base working part is large. capacity, but if the outer diameter of the base working part is small, 3
Due to the presence of two grooves, the proportion of the hard abrasive adhesion area in the working part of the cutting tool base decreases, and the area in contact with the tooth or tooth restoration also decreases, resulting in poor cutting ability. It's more noticeable.

In addition, when cutting flat teeth or dental restorations, a cutting tool with grooves formed by stacking Solopan bead-like shapes with a hexagonal symmetrical cross section of the second shape is difficult to cut when cutting flat teeth or tooth restorations. Not only is the cutting ability inferior due to the small area of the hard abrasive particles that come into contact with the surface, but also the cutting part is machined into a groove shape, so it is necessary to use a normal cutting tool without grooves to machine the groove shape again. It is necessary to adjust the parts that have been

Furthermore, in a cutting tool having a left-handed threaded groove of the third shape, the width of the groove and the width of the hard abrasive-fixed portion are approximately equal, so that the hard abrasive-fixed portion that contacts the tooth or tooth restoration is The area is reduced to approximately 1/2, and the cutting ability is inferior at the same rotation speed.

[Means for solving problems]

The dental cutting tool according to the present invention has excellent cutting ability, and at the same time, is capable of efficiently discharging cutting waste and discharging heat. A cutting tool in which a right-handed spiral groove is formed, and a hard abrasive grain fixing part is formed on the outer circumferential surface other than the groove, and hard abrasive grains are fixed to the outer circumferential surface, and the axis of the working part of the base body is If the diameter of a cross section perpendicular to D is D, the total width of the groove in that cross section is within the range of (1150 to 215) do.

With this configuration, the grooves and the hard abrasive fixing parts are in continuous and alternate contact with each other, and if the diameter of the cross section of the base working part perpendicular to the axis of the base working part is D, the hard abrasive grains in that cross section are fixed. Except for the end point on the tip side of the base working part, the total width of the grooves is within the range of (1150 to 215) H is discharged and heat is removed. This cutting operation has the advantage that the tooth or tooth restoration is not processed into a groove shape, and there is no need for adjustment using an ordinary cutting tool without grooves.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dental cutting tool according to the present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is a side view of one embodiment of the cutting tool according to the present invention, FIG. 2 is an enlarged view of the A-AM end face in FIG. 1, and FIG. 3 is a side view of another embodiment of the cutting tool according to the present invention. A side view, FIG. 4 is an enlarged front view taken along the line B-B in FIG. 3, FIG. 5 is a side view of another embodiment of the cutting tool according to the present invention, and FIG. - It is an enlarged view of the C line end front.

In the drawings, reference numeral 1 denotes a base body machined from a steel wire having good workability and strength enough to withstand high-speed cutting work, preferably stainless steel wire having good corrosion resistance.

Reference numeral 2 denotes a working part of the base body 1, and its shape is basically a conical shape, a cylindrical shape, or a spherical shape, but it may also have a shape that is a combination of these shapes.

Reference numeral 3 denotes one or more right-handed spiral grooves formed on the outer circumferential surface of the working part 2 of the base body 1, and the cross-sectional shape of the grooves 3 may be semicircular or V-shaped. Even if it is U-shaped, various shapes can be adopted as long as they can effectively improve cutting ability, discharge cutting debris, and eliminate heat. 4 is a natural or artificial diamond, aluminum oxide, carborundum, cubic boron nitride, or TiC-based material fixed to the outer peripheral surface of the working part 2 of the base 1 except for the groove 3.

This is a hard abrasive fixing part to which hard abrasive grains such as ZrO, Si, N, ceramics, etc. are fixed. Although nickel or chromium electroplating is used as in the embodiments shown in Figures 3 and 6, brazing methods may also be used as in the embodiments shown in Figures 3 and 4, or in combination 5 is a neck portion provided between the base of the working portion 2 of the base body 1 and the handle portion.

The right-handed spiral groove 3 is formed by mechanically forming the right-handed spiral groove 3 on the outer peripheral surface of the working part 2 of the base 1 before fixing the hard abrasive grains to the working part 2 of the base 1, After insulating this groove 3, the simplest method is to use electroplating to fix hard abrasive grains to the outer peripheral surface excluding the groove 3. Before this, a right-handed spiral insulation part is formed on the outer peripheral surface of the working part 2 of the base body 1.

Hard abrasive grains can also be fixed to the outer circumferential surface excluding the insulating portion by electroplating. Further, after fixing hard abrasive grains to the working part 2 of the base body 1 using an electroplating method or a brazing method, the outer peripheral surface of the working part 2 of the base body 1 is mechanically processed into a right-handed spiral shape. It is also possible to form grooves 3.

Although it is desirable that the width W of the groove 3 is basically the same, it is not necessarily limited to the same width over the entire length of the groove 3. For example, if the shape of the working part 2 of the base 1 is conical, the base 1
It is difficult in machining to form the groove 3 at the tip of the working part 2, and also leads to a decrease in cutting ability, so the width W of the groove 3 at the tip needs to be gradually narrowed toward the tip.

In this case, it is also effective to discharge the cutting H. Also.

When the shape of the base working part is spherical, the circumferential speed near the tip is small and the cutting ability of the groove 3 at the tip is not effective, so the width W of the groove 3 at the tip gradually narrows toward the tip. The width W of the grooves 3 to which hard abrasive grains are not fixed is preferably the sum of the widths W of the grooves 3 in the cross section perpendicular to the axis of the working part 2 of the base body 1, where D is the diameter of the cross section. W is.

The length of the outer circumference of the cross section of the base 1 excluding the end point on the tip side of the working part 2 is less than half (1150 to 2/5)×D
It is necessary to be within the range of . The width W of the groove 3 is the diameter of a cross section perpendicular to the axis of the working part 2 of the base body 1 as D. Except for the part (1150)
If yc is less than D, the effect of continuous alternate contact between the caps 3 and the hard abrasive grain fixing portions 4 will be lost, leading to a decrease in cutting ability and making it difficult to discharge cutting debris and heat. Further, if the width W of the groove 3 is the diameter of a cross section perpendicular to the Fill line of the working part 2 of the base body 1, then the sum W of the width W of the groove 3 in that cross section is the tip of the working part 2 of the base body 1. When (215) x yc D is exceeded except for the end point of the side, the ratio of the area of the hard abrasive grain adhering part 4 to the working part 2 of the base body 1 becomes small, and it becomes easy to discharge cutting waste and eliminate heat. However, this is undesirable because the cutting ability decreases.

The inclination angle θ of the base body 1 with respect to the axis of the working part 2 is a factor that particularly affects the cutting ability, and when the inclination angle 0 is close to 06 or 0°, the cutting ability is particularly excellent. This gives a large impact to the reconstruction, causing pain to the patient, and this tendency decreases as the inclination angle θ becomes larger.
However, when the inclination angle θ is within the range of 5° to 60°, the impact on the tooth or tooth restoration is suppressed to a low level, and the cutting ability is excellent. Moreover, when the inclination angle θ exceeds 60°, the cutting ability decreases. Therefore, it is preferable that the inclination angle θ of the base body 1 with respect to the longitudinal axis direction is within the range of 5° to 60°. Note that it is preferable that this inclination angle θ is constant over the entire length of the working section 2.

As shown in the embodiment shown in FIG. 5, since the length of the working part 2 is long, the length of the neck part 5 cannot be increased. When forming the spiral groove 3, if there is a possibility that the groove will extend to the handle of the base body 1, the inclination angle θ may be set within a range of 60° or less only on the handle side of the working part 2. There is no problem in increasing the size within the room.

The number of grooves 3 to which hard abrasive grains are not fixed is also a factor that greatly influences cutting ability, discharge of cutting waste, and removal of heat. In the case of the cutting tool shown in FIG.

The number of grooves 3 is 2, but if the number of grooves is 3 or more, the discharge of cutting H and heat will be better.
If the outer diameter is small and the outer circumference is short, the area of the hard abrasive fixing part 4 occupying the working part 2 of the base body 1 becomes small, and the area in contact with the tooth or tooth restoration is also small, resulting in poor cutting ability. This tendency is more pronounced when the load is low. Therefore, it is basically desirable that the number of grooves 3 is two, but the length of the working part is longer than that of the cutting tool shown in FIGS. When the basic shape of the working part 2 is conical, if the number of grooves 3 is two, the outer diameter of the working part 2 of the base 1 becomes smaller from the center to the tip of the working part 2, and the base Hard abrasive fixed part 4 occupying working part 2 of 1
The area of the groove 3 is smaller and the area in contact with the tooth or tooth restoration is also smaller, and the cutting ability from the center to the tip of the working part 2 is inferior. It is preferable to set the number to one.

Further, the purpose of use of the dental cutting tool according to the present invention is to cut teeth or tooth restorations, and the hard abrasive grains to be fixed are tooth enamel with a Knoop hardness of around 340 or a Knoop hardness of 30 to 150. Although there is no particular limitation as long as it has the hardness necessary to cut the dental restoration, natural or artificial diamonds are particularly excellent in terms of cutting ability and durability, and it is desirable to use these.

〔Example〕

The cutting tool shown in FIG. 1 has a right-handed helical shape on the outer circumferential surface of a working part 2 of a base body 1 with an inclination angle θ of 30° to the axis of the base body 1, and a width W in a cross section perpendicular to the axis is 0. .3
5 mm, and two grooves with a width of 1110 to 115 of the outer circumferential length excluding the end point on the tip side of the working part 2 of the base body 1 [the total width W of the groove 3 corresponds to (115 to 215) X πD] This dental cutting tool has a semicircular groove 3 formed therein, and a hard abrasive grain fixing part 4 formed with natural diamond abrasive grains fixed by electroplating on the outer peripheral surface except for the groove 3.

The cutting tool shown in FIG. 3 has a right-handed helical shape with an inclination angle θ of 10 degrees to the axis of the base body 1, and a width W in a cross section perpendicular to the axis line. is 0.25 nm each, and one V-shaped groove 3 with a width of 3750 to 7150 mm of the outer circumference excluding the end point on the tip side of the working part 2 of the base 1 from the tip to the center of the working part, 2 grooves from the center to the base of the working part [the total width W of the groove 3 is (615
0 to 14150) corresponding to It is.

Furthermore, in the cutting tool shown in FIG. 5, the inclination angle 0 with respect to the axis of the base 1 on the outer peripheral surface of the working part 2 of the base 1 is 30° from the tip of the working part 2 to 1 m before the root, and 1 ms + from the root.
It has a right-handed spiral shape with an angle of 50° from the front to the base, and the width W in the cross section perpendicular to the axis is 0.45 m, and the base 1
Excluding the end point on the tip side of the working part 2, the outer circumference length is 41
There is one groove 3 with a width of 50 to 9150 mm from the tip to the center of the working part, and two grooves 3 from the vicinity of the tip to the base of the working part [the total width W of the groove 3 is (8150 to 18150) xπD
This dental cutting tool has a hard abrasive grain fixing part 4 formed with artificial diamond abrasive grains fixed by electroplating on the outer peripheral surface except for the groove 3.

[Effect]

The dental cutting tool according to the present invention having the above-described structure has a right-handed spiral groove 3 formed on the outer circumferential surface of the working part 2 of the base body 1, and hard abrasive grains on the outer circumferential surface except for the groove 3. is a cutting tool in which a hard abrasive grain fixing part 4 is formed, and if the diameter of a cross section perpendicular to the axis of the working part 2 of the base body 1 is D, the width of the groove 3 in that cross section is The sum of W is W.

Except for the end point on the tip side of the working part 2 of the base body 1 (115
0 to 215) is within the range of

Such a dental cutting tool according to the present invention has a right-handed helical groove 3 formed on the outer circumferential surface of the working part 2 of the base body 1, and a hard abrasive grain is fixed to the outer circumferential surface excluding the groove 3. Since the abrasive grain fixing portion 4 is formed, the cutting performance or cutting feeling when cutting a tooth or dental restoration has a directionality closer to that of a dental bur than that of a grindstone due to its spiral structure. Therefore, in the case of dental turbines in which the direction of rotation of the cutting tool cannot be adjusted, it is very difficult for dentists who are accustomed to conventional forming methods to have a right-handed helical direction, which is the same as that of conventional dental burs, especially carbide burs. Because of the difference in the helical direction, there is no need to cut deeply into the tooth or tooth restoration and damage the tooth, or to learn a different preparation method than the conventional one. law can be used.

〔effect〕

The dental cutting tool according to the present invention as described in detail above has a conventional cutting tool having three right-handed helical grooves with a slight inclination angle with respect to the axis of the working part, and a cutting tool with a cross section of 6.
This product improves the reduction in cutting ability that was a drawback of cutting tools with grooves formed by stacking square Solopan beads and cutting tools with left-handed thread grooves.
In particular, when the outer diameter of the working part of the base is small, there is almost no reduction in cutting ability under low loads, and it has high cutting ability even under high loads, and it can also cut teeth or dental restorations. This has the advantage that not only is the tooth or tooth restoration not machined into a groove shape, but the finished cut surface is very flat, so there is no need to re-adjust it using a normal cutting tool without grooves. -ing

In addition, the continuous alternating contact between the groove and the fixed part of the hard abrasive grains and the selection of the total width of the groove that prevents a decrease in cutting ability despite this continuous alternating contact automatically discharge cutting debris and eliminate heat. Not only is it done, but also teeth or tooth l!
Since the WRM given to the JtIt product is kept low, patients are not forced to suffer from cancer.

As described above, the dental cutting tool according to the present invention greatly contributes to dental treatment.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the cutting tool according to the present invention, and FIG. 2 is an enlarged view of A-APjA in FIG. 1. FIG. 3 is a side view of another embodiment of the cutting tool according to the present invention. A side view, FIG. 4 is an enlarged view of the B-B edge surface in FIG. 3, FIG. 5 is a side view of another embodiment of the cutting tool according to the present invention, and FIG.
6 which is an enlarged view of the front end of C line 1...Base body 2...Working part 3...Groove 4...Hard abrasive grain fixed part 5...Neck part D... Diameter W of the cross section perpendicular to the axis of the working part 2...Width W of the groove 3...Sum of the width W of the groove 3

Claims (1)

[Claims] 1. A right-handed spiral groove (3) is formed on the outer peripheral surface of the working part (2) of the base (1), and hard abrasive grains are formed on the outer peripheral surface except for the groove (3). Fixed hard abrasive grain part (4)
is formed, and if the diameter of a cross section perpendicular to the axis of the working part (2) of the base body (1) is D, then the sum of the widths (w) of the grooves (3) in that cross section. A cutting tool characterized in that (W) is within the range of (1/50 to 2/5) x D except for the end point on the tip side of the working part (2) of the base (1). 2. The cutting tool according to claim 1, wherein the groove (3) is one groove. 3. The cutting tool according to claim 1, wherein the groove (3) has two grooves. 4. The cutting tool according to any one of claims 1 to 3, wherein the hard abrasive grains are natural diamonds. 5. The cutting tool according to any one of claims 1 to 3, wherein the hard abrasive grains are artificial diamonds. 6 The inclination angle (θ) of the groove (3) is the working part (2) of the base (1).
) 5° to 60° with respect to the axial direction of the cutting tool according to any one of claims 1 to 5.