JP3069536U - Turning tools - Google Patents

Abstract

(57) [Problem] To focus on the fact that the longitudinal elastic modulus of a high-hardness material such as cemented carbide is large, a part of a shank is used so that the cemented carbide can be effectively used. In this case, even when a material having relatively low hardness is used for the shank, the price of the product is suppressed while effectively suppressing chatter. A turning tool (10) including a shank (11) fixed to a tool holder (20) and a cutting tip (12) provided at the tip (11a) of the shank for turning. Sides 11b and 11c of the shank 11 which are perpendicular to the direction of the load F
In addition, a pair of reinforcing members 30 made of a material having a higher hardness than the material of the shank and having a higher modulus of elasticity, each of which is simultaneously attached to the shank, are provided.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a turning tool for turning a workpiece used in a turning machine such as a lathe.

[0002]

[Prior art]

 Generally, in a lathe, a turning tool fixed to a tool holder is used to fix to a chuck and strike against a rotating workpiece. This turning includes outer turning, inner turning, taping, parting-off, and several other types of turning, and a turning tool according to each turning type is used. Among them, a tool used for internal turning for turning the inner diameter of a hole is generally called a boring bar, and a handle portion called a shank fixed to the tool holder, and a cutting tip provided at a tip portion of the shank. The cutting tip is pressed against the workpiece and turns it. Therefore, when a deep hole is machined in the boring bar, the shank is lengthened to cope with it.

[0003] By the way, a large cutting load acts on the cutting tip during turning on the boring bar, and this load causes chatter. This chatter tends to increase as the shank becomes longer, and this chatter causes deterioration of the finished surface accuracy of the machined surface and loss of the cutting insert due to vibration. Therefore, it is necessary to suppress chatter by increasing the rigidity of the shank.

[0004]

[Problems to be solved by the invention]

 By the way, the shank is usually formed of a steel material. However, there is a type in which the entire shank is formed of a cemented carbide in order to increase rigidity in order to prevent chatter. When the entire shank is made of a cemented carbide in this way, the one in which the seat portion for holding the cutting tip is formed by lost wax molding and both are silvered is generally used. However, cemented carbides are extremely expensive, and the use of cemented carbide for the entire shank would significantly increase the cost of boring bars compared to those made of steel. There were challenges.

Therefore, the present invention has been made in view of such a conventional problem, and pays attention to the fact that a high hardness material such as a cemented carbide has a large longitudinal elastic modulus. By using a part of the shank to reinforce it so that the coefficient can be used effectively, even if a relatively low-hardness material is used for the shank, the product price can be reduced while effectively suppressing vibration. An object of the present invention is to provide a turning tool that can be kept low.

[0006]

[Means for Solving the Problems]

 To achieve the above object, the turning tool of the present invention will be described with reference to the accompanying drawings. The turning tool 10 is provided at a shank 11 and a cutting portion provided at a tip portion 11a of the shank 11 for turning. The shank 11 is provided with a tip 12 and has a longitudinal elasticity coefficient superior to that of the material of the shank 11 on both side surfaces 11b and 11c of the shank 11 which are perpendicular to the direction of the load F during turning that acts on the cutting tip 12. A pair of reinforcing members 30 each made of a material having high hardness and simultaneously roasted to the shank 11 are provided.

According to this configuration, the location where the high-hardness reinforcing member 30 is soldered is in the direction of the load F applied to the cutting tip 12 during turning, that is, in the direction perpendicular to the direction in which chatter occurs. Side faces 11b and 11c of the resulting shank, and the side faces 11b and 11c receive a load F in the bending direction when chatter occurs. Accordingly, the reinforcing member 30 which is soldered and integrated with both side surfaces 11b and 11c undergoes longitudinal elastic deformation. However, since the reinforcing member 30 has an excellent longitudinal elastic coefficient, the bending deformation is reduced. Therefore, the shank 11 itself can be prevented from being bent in the direction of the load F, so that chatter can be effectively suppressed.

In this case, the high-hardness expensive reinforcing member 30 may be provided in a part of the shank 11, and the shank 11 itself can be made of a relatively low-hardness and inexpensive material. The product price as a cutting tool can be kept low while showing good results.

In addition, high heat is generated when the reinforcing member 30 is soldered to the shank 11, and a large difference in the coefficient of thermal expansion existing between the material of the shank 11 and the high hardness reinforcing member 30 causes Although the shank 11 may be distorted or cracked, in the present invention, since the pair of reinforcing members 30 are simultaneously soldered to both sides 11b and 11c of the shank 11, the distortion generated in the shank 11 is reduced. , 11c, the reinforcing members 30 can be joined together while canceling each other. Therefore, the shank 11 can be kept straight even by brazing, and can be prevented from being damaged by cracks or the like.

Further, by forming the material of the shank 11 as a steel material and the reinforcing member 30 as a cemented carbide, the cemented carbide can be soldered to a steel material which is a material of a commonly used turning tool. In other words, the shank 11 itself can be made of an inexpensive conventional steel material. For this reason, if necessary, the conventional turning tool can be joined with a cemented carbide by brazing to easily prevent chattering.

[0011]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 to 4 show an embodiment of the turning tool according to the present invention, FIG. 1 is a front view of the turning tool, FIG. 2 is an enlarged sectional view taken along line AA in FIG. 1, and FIG. FIG. 4 is an explanatory view showing a load acting on a turning tool.

The turning tool 10 according to the present invention basically includes a shank 11 fixed to a tool holder 20 and a cutting tip 12 provided at a tip 11 a of the shank 11 for turning. The object is to reinforce the shank 11 to suppress chatter. The basic structure of the shank 11 is that, on both side surfaces 11b and 11c of the shank 11, which is perpendicular to the direction of the load F during turning that acts on the cutting tip 12, a high elastic modulus higher than the material of the shank 11 is provided. A pair of reinforcing members 30 made of a material of hardness, each of which is simultaneously roasted to the shank 11, are provided.

That is, as shown in FIGS. 1 and 2, the turning tool according to the present embodiment is described by taking an example of a boring bar 10 for boring, and a shank 11 is used as a general turning tool. And its cross-sectional shape is rectangular. As the steel material, for example, SCM439 is used, and when heat treatment is performed, HRC40 to 45 is used. A cutting tip 12 is fixed on the upper surface of the tip 11a of the shank 11, but the cutting tip 12 may be configured as a replaceable throw-away tip. It can also be configured as a figure.

The boring bar 10 is fixed by inserting it into a mounting recess 21 of a tool holder 20 as shown in FIG. 3, and tightening it with a fixing bolt 22 from above. The tool holder 20 is moved and adjusted in the X and Y directions on a horizontal plane by operating a vertical feed handle and a horizontal feed handle (not shown), so that a depth feed and a radial feed when machining the boring hole 24 of the work 23 are performed. Is performed with high accuracy.

FIG. 4 shows a state in which the cutting tip 12 turns the inner periphery of the boring hole 24, and a downward turning load F is generated on the cutting tip 12 along the rotation direction R of the work 23. This load F is input to the tip 11a, which is the free end of the shank 11, and causes vibration that causes the shank 11 to bend up and down, and this vibration appears as chatter.

In this embodiment, a pair of cemented carbide 30 as a reinforcing member is provided on both left and right side surfaces of the shank 11, that is, both side surfaces 11 b and 11 c which are perpendicular to the direction of the load F. And are joined by soldering. The cemented carbide 30 is formed by, for example, K20 defined by JIS (B4053), and has a length L from the vicinity of the front end 11a to the rear end 11d along the shape of the side surfaces 11b and 11c. And a predetermined thickness t.

The pair of cemented carbides 30 are simultaneously soldered while being pressed against both side surfaces 11b and 11c. Then, as shown in FIG. 2, the outer surface of the brazed cemented carbide 30 is formed in a substantially arc shape so as to draw a smooth curve at the four corners of the shank 11, or the corner is formed so as to be convenient for handling. In this case, a stress concentration portion such as a step is not provided between the shank 11 and the cemented carbide 30 between the shank 11 and the cemented carbide 30.

With the above configuration, the boring bar 10 according to the present embodiment has a pair of high hardness on both sides 11 b and 11 c of the shank which is perpendicular to the load F direction at the time of turning that acts on the cutting tip 12. Are cemented together by brazing to increase the rigidity of the shank 11. At this time, the direction of the load F becomes a direction in which chatter occurs, and the cemented carbide 30 is joined to the side surfaces 11b and 11c which are perpendicular to the direction in which chatter occurs. Due to the large modulus of elasticity of the alloy 30, the bending deformation of the shank 11 at the time of chattering can be reduced, so that chattering of the boring bar 10 can be effectively suppressed.

As described above, in the present embodiment, although the chatter of the boring bar 10 having the shank 11 formed of steel material can be effectively suppressed, the high-hardness and expensive cemented carbide 30 is formed by the shank 11. May be provided in a part of. For this reason, the shank 11 itself can be made of an inexpensive material having a relatively low hardness such as steel (SCM439), so that the shank 11 exhibits good results in suppressing chatter and reduces the product price as a cutting tool. Can be suppressed.

Incidentally, the cemented carbide 30 is brazed to the side surfaces 11b and 11c, but at this brazing, extremely high heat is generated. For this reason, due to a large difference in the coefficient of thermal expansion between the steel material, which is the material of the shank 11, and the hard metal 30 having high hardness, the shank 11 is distorted or cracked in some cases. It cannot be commercialized. However, in the present embodiment, a pair of cemented carbide 30 is simultaneously soldered to both sides 11b and 11c of the shank 11, so that the distortion generated in the shank 11 is prevented by the both sides 11b and 11c. The cemented carbide 30 can be joined while offsetting each other. Therefore, the shank 11 can be kept straight even by brazing, and can be prevented from being damaged by cracks or the like.

In the present embodiment, since the shank 11 can be cemented to a general boring bar 10 formed of a steel material, the cemented carbide 30 can be soldered to the general boring bar 10 as necessary. By hardening the hard alloy 30, it is possible to easily take measures against chatter.

By the way, in this embodiment, as the material of the shank 11 and the reinforcing member, SCM439 (heat treatment is HRC 40 to 45) is used for the shank 11 and the cemented carbide 30 of K20 is used for the reinforcing member. The balance between steel and strength can be made favorable, but of course, the present invention can be achieved even if other materials are selected as the steel material and the reinforcing member.

In this embodiment, the boring bar 10 has been described as an example. However, the present invention is not limited to the boring bar 10 and can be applied to other turning tools such as an external turning tool and a parting tool. Needless to say.

[0024]

[Effect of the invention]

 As described above, the turning tool according to the present invention has a high vertical modulus of elasticity superior to that of the material of the shank on both sides of the shank which is perpendicular to the load direction during turning acting on the cutting tip. Since a pair of reinforcing members made of a material of hardness are soldered, a high-hardness expensive reinforcing member is set on a part of a shank made of a relatively low-hardness and inexpensive material, and a cutting tool is used. Despite being able to keep the product price low, it is possible to effectively suppress chatter by reducing the bending of the shank itself in the load direction by the reinforcing member having excellent longitudinal elastic modulus. Can be.

Further, since the pair of reinforcing members are simultaneously brazed on both side surfaces of the shank, the distortion generated in the shank due to the heat generated at the time of the brazing is mutually offset on both sides. can do. Therefore, the shank can be kept straight even by brazing, and can be prevented from being damaged due to cracks and the like, and the product value can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a front view of a turning tool according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line AA in FIG.

FIG. 3 is a perspective view of the turning tool according to the embodiment of the present invention in use;

FIG. 4 is an explanatory view of a load acting on a turning tool according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 boring bar (turning tool) 11 shank 11a tip 11b, 11c side surface 12 cutting tip 20 tool holder 23 work 24 boring hole 30 cemented carbide (reinforcing member) F turning load

Claims (2)

[Utility model registration claims] 1. A turning tool 10 comprising a shank 11 and a cutting tip 12 provided at a tip end portion 11a of the shank 11 for turning. Both side surfaces 11b of the shank 11, which are perpendicular to the direction,
11c is made of a material having a higher hardness than the material of the shank 11, and
A turning tool, comprising a pair of reinforcing members 30 to be soldered to one. 2. The material of the shank 11 is a steel material.
The turning tool according to claim 1, wherein the reinforcing member (30) is a cemented carbide.