JPH0112915Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a cone reamer particularly suitable for internal chamfering of pipes and the like.

Prior art When a cone reamer is attached to a pipe machine to perform internal machining, it lacks rigidity in holding the workpiece (reamer) and workpiece (pipe, etc.) compared to when using a lathe, etc. The reamer tends to move inside. Furthermore, due to the characteristics of the reamer, it is necessary to process workpieces from small to large diameters, but the force with which the reamer is pressed against the workpiece varies depending on the operator and is not constant.

As a result of the above, the finished surface becomes wavy or uneven, resulting in a disadvantage that a clean finished surface cannot be obtained. Depending on how much force is applied, the reamer may dig into the inner peripheral surface of the pipe, resulting in overload of the main shaft motor and damage to the reamer.

The above-mentioned drawback is that the cutting edge of the reamer and the so-called second recess, which prevents the cutting edge from digging in too much, are provided at the same position on the circumference of the reamer body. It is caused by In other words, the support part is set back in the radial direction by a predetermined amount from the cutting blade part, but the position of the support part depends on the blade angle of the cutting blade part, so if the blade angle is made smaller, the support part becomes smaller. As a result, the support part cannot perform the function of preventing the cutting edge from digging in because the position is too far back in the radial direction from the cutting edge, and conversely, when the blade angle is increased, the support part becomes almost the same as the cutting edge. As a result, the support part interferes with the inner circumference of the workpiece, and the cutting blade part becomes unable to perform cutting. Of course, the blade angle is determined taking into account the above points, but due to the above-mentioned runout of the reamer and the degree of precision of the machined surface, it is almost impossible to obtain an ideal machining condition, and therefore, the above-mentioned The following problems arose. This is also due to the structure in which the formation of the support part is influenced by the blade angle, and therefore, if the support part could be formed completely independent of the cutting edge part, the above problem would be solved. Ru.

Purpose of the invention In view of the above, the present invention provides a support section separately from the cutting edge of the reamer, that is, the cutting edge and the support section are separated, so that the cutting edge can be adjusted only with consideration to sharpness. The support part can be set by considering the depth of cut at one time.
This aims to solve the problems of the prior art as described above.

Structure of the Device In order to achieve the above object, the present invention has a cutting edge on the generatrix of a substantially conical body, and a circle passing through the cutting edge in any cross section including the cutting edge. A cone reamer is provided in which a support portion is formed separately from the cutting blade portion at a position that is a predetermined amount inside the cutting blade portion and spaced apart from the cutting blade portion in the circumferential direction.

Embodiments Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 and 2 show an example of the structure of a conventional cone reamer, in which, for example, five cutting edges 3 are formed along the generatrix of a conical main body 1. These cutting edges are on the same circumference. If the blade angle θ of these cutting blades 3 is too small, the cutting blades will dig into the pipe P too much (Fig. 3).
Moreover, if it is too large, the support part 5 will interfere and cutting will not be possible (FIG. 4). Adjacent to the cutting blade 3, a support portion 5 called a second cut is provided. As shown in an enlarged view in FIG. 5, this support portion 5 is located on a circle having a radius t shorter than the circle C drawn by the cutting blade 3. This support part 5
is the inner diameter of pipe P (Figures 3 and 4) (corresponds to circle C)
By hitting the reamer, the amount of reamer biting at one time is suppressed to "t". Therefore, the size of "t" should originally be set considering only the amount of one-time biting, but in the past, since the support portion 5 is formed by the blade angle of the cutting edge portion 3, Moreover, in practice, the blade angle is rather determined by the sharpness of the cutting edge 3, etc., and therefore tends to be in an unstable state as shown in FIG. 3 or 4. To be precise, the sharpness of the cutting edge 3 mainly depends on the angles α and β and the lengths l and m shown in FIG. ) and the height m of the cutting edge portion are larger, and the length l of the cutting edge portion 3 is smaller, the sharpness improves.

Furthermore, as is clear from FIGS. 1 to 5, according to the prior art, the support part 5 is located on the downstream side of the cutting blade 3 when viewed in the direction of rotation of the reamer (in the direction of the arrow). It should be noted that the function of keeping the cutting depth constant cannot be achieved at all. That is, since the supporting portion 5 only traces the cutting area by the cutting blade 3 from behind the cutting blade 3, in reality
Depending on how the force is applied, it is possible to cut more than t at a time. That is, the support portion 5 has no value at all as far as the purpose of keeping the depth of cut at one time constant is concerned. Moreover, such a conventional cone reamer requires grinding using a grinder, which requires a lot of time and labor and has poor workability.

In view of the prior art as described above, in the present invention, the support portion 15 is formed separately from the cutting edge portion 13. That is,
The cutting edge and support part are completely separated in the circumferential direction,
The cutting edge portion can be designed with consideration only to its function as a cutting edge portion, and the support portion 15 can be designed taking into consideration only its function as a support portion. Further, according to the present invention, the support portion is formed upstream of the cutting edge portion. As shown in FIGS. 6 to 9, the cone reamer according to the present invention has a conical body 11.
For example, there are two cutting blades 13 along the generatrix of the cone reamer, and two supporting parts (surfaces) 15 are provided on the upstream side of the cutting blades 13 when viewed in the rotational direction of the cone reamer. Note that the portion 17 corresponding to the support portion 5 of the prior art is merely a relief for giving the cutting edge 13 a cutting edge angle. In the illustrated embodiment, two cutting blades 13 and two supporting surfaces 15 are arranged diametrically opposite each other at 90° intervals, but the number and arrangement thereof are not limited to those shown.

The cutting edge 13 and the supporting surface 15 are formed in the following manner (see FIG. 10).

That is, in any cross section of the conical body 11 of the reamer, the center O ₁ is eccentric from the center O by an amount e.
A conical generatrix surface S ₁ of radius R is machined with the center at , and the center O ₂ is eccentric from the center O by an amount e in the opposite direction to O _1.
A conical generatrix surface S ₂ of radius R is machined around . The cutting edge 13 and the support surface 15 are then formed by cutting off the hatched portion 25, for example at a right angle. Note that the support surface 15 does not necessarily have to be a plane, and may be a ridgeline along the generatrix. By doing the above, the supporting surface 15 is aligned with the cutting edge 13 with respect to the center O.
It is located radially inward by a depth t corresponding to the eccentricity e. Further, the opposite side in the diametrical direction is formed in a similar manner so as to have a mirror image relationship. The size of t and the clearance angle of the cutting edge are the eccentricity e
Alternatively, it can be set arbitrarily by changing the size and angle of the cut portion 25. Note that the resection portion 30 is ultimately removed to reduce the weight of the reamer.
There is no harm in leaving it as it is as part of the conical surface.

In the above-mentioned embodiment, the shape, number of teeth, etc. were determined by the conditions in which the reamer cone was machined, but by machining the reamer cone using a known lost wax method, the cutting edge could be reduced to 1.
It is also possible to create a reamer with an arbitrary combination of two or more supporting parts.

Effects of the invention With the above configuration, according to the invention, by separating the cutting edge part and the support part of the reamer blade, the cutting conditions of the conventional reamer can be simplified and the function as a reamer can be made more stable. can be done.
Furthermore, since the cutting edge does not also serve as a support, it can be set simply by improving the sharpness. In reality, the durability of the knife is taken into account. The support portion can be set simply by determining the depth of cut for one press. As mentioned above, in the conventional reamer, the depth of cut varies depending on the reamer pressing force F (FIG. 1).

[Brief explanation of the drawing]

Figures 1 and 2 are a front view and right side view of a conventional cone reamer, Figures 3 and 4 are diagrams illustrating over-cutting and uncutting conditions of the conventional reamer, respectively, and Figure 5 is the same as Figures 1 and 2. FIG. 6 is a perspective view of the cone reamer according to the present invention; FIG. 6 is a perspective view of the cone reamer according to the present invention;
9 is a front view, left side view, and right side view of the cone reamer shown in FIG. 4, and FIG. 10 is an enlarged view for explaining the method of manufacturing the cone reamer according to the present invention. 11... Main body, 13... Cutting blade, 15... Supporting surface.

Claims (1)

[Scope of utility model registration request] A cutting edge is directly and integrally formed on the generatrix of a substantially conical main body, and in any cross section including the cutting edge, the cutting edge is located inside the circle passing through the cutting edge by a predetermined amount and from the cutting edge. A cone reamer in which a support part is formed separately from the cutting blade part at a position separated in the circumferential direction.