WO2003002316A1 - Rotary tool - Google Patents

Abstract

A rotary tool, wherein a tubular bush (20) having an axial center part partly formed thin so as to be reduced in diameter is fittingly inserted into a center hole (12) of a tubular tool main body (11), the bush is fixed to both ends of the center hole of the tool main body by shrinkage fit, brought into contact with the center hole, in fluid-tight state, on both end sides of the tool main body, and provided with annular space parts (24a, 25a) in the spaces thereof from the center hole at the axial intermediate parts of the tool main body, and fluid is sealed into the annular space part and pressurized to reduce the diameter of the thin walled part of the bush in the state of a rotating shaft (31) being fittingly inserted into the center hole through the bush, whereby the rotary tool can be fixed to the rotating shaft.

Description

 Description Rotary tool Technical field

 The present invention relates to a rotary tool fixed to a rotary shaft via a bush. Background art

 In recent years, this type of rotary tool has been required to be particularly inexpensive and have higher rotational accuracy, that is, a higher degree of uniformity of the turning radii of a plurality of cutting edges located on the outer periphery of the rotary tool. I have. As a conventional rotary tool, for example, a woodworking cylinder disclosed in Japanese Utility Model Laid-Open No. 62-75902 is known. In this plane cylinder, an inner sleeve (bush) of the same length is closely fitted in the center hole of the plane cylinder. The inner sleeve is sealed at both ends with the boundary with the plane hole of the plane cylinder in an airtight manner. I have. As a result, an annular space is formed between the both ends and the center of the boundary surface between the plane cylinder and the inner sleeve so that the inner sleeve side is thick enough to be deformable. In addition, an injection valve that can inject and seal the pressure medium and a stopper that can reduce the pressure of the pressure medium are embedded in the annular cylinder in the plane cylinder, and the pressure medium is injected through the injection valve. Thereby, the inner diameter of the inner sleeve at the annular space position can be reduced. As a result, the plane cylinder can be fixed with good balance to the rotating shaft fitted into the center hole.

However, in the case of the above-mentioned rotary tool, the welding conditions for welding the boundary surface between the plane cylinder and the inner sleeve were strict and the work was difficult, so the work required skill. In addition, since welding is performed while drawing a line by moving the welding location, it took a long time to perform the work. In addition, every welding spot Because of the time lag, the effect of welding heat applied to the rotating tool unevenly, causing thermal distortion due to thermal stress, which reduced the accuracy of the rotating tool. In order to remove such thermal stress, it is necessary to perform reheating treatment after welding, but it is also difficult to completely remove the thermal stress. When the rotary tool body is made of aluminum alloy, it is more difficult to weld a steel bush. For these various reasons, conventional rotary tools have increased manufacturing costs and have not always had sufficient rotational accuracy.

 An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a rotary tool in which a bush is fixed to a center hole at low cost while improving rotation accuracy. Disclosure of the invention

 A feature of the present invention is that a thin cylindrical bush, at least part of which can be reduced in diameter in the axial direction, is inserted into the center hole of the cylindrical tool body, and the bush is formed at both ends of the tool body. Side and the center hole in a liquid-tight manner, and an annular space is provided between the center hole and the center hole of the tool body, and the rotating shaft is inserted into the center hole via the bush. With the rotating tool fixed to the rotating shaft by filling the fluid in the annular space and pressurizing to reduce the thin part of the bush, the bush is burned at both ends of the center hole of the tool body. It is to be secured by a fit (or a cold fit, or a combination).

In the present invention, the bush can be easily and uniformly fixed to both end sides of the center hole of the tool body by shrink fitting simply by inserting the bush into the center hole of the heated tool body. As a result, according to the present invention, it is possible to provide an inexpensive and accurate rotary tool. In addition, through the bush The rotating tool is tightly fixed to the rotating shaft by sealing the fluid in the annular space and pressurizing the thin portion of the bush while the rotating shaft is fitted in the center hole.

 Further, it is preferable that the bush is shrink-fitted (or cold-fitted or used together) with an adhesive in the center hole of the tool body. Thereby, the bush and the tool body can be more securely fixed. As a result, according to the present invention, it is possible to prevent the thin portion from extending in the axial direction due to the injection of the fluid into the annular space, and to prevent the rotating shaft from being slightly bent.

 Further, it is preferable that the bush has an inner diameter at both ends in the axial direction larger than an inner diameter of the thin portion. Thus, even if the bush is shrunk into the tool main body and both ends in the axial direction are reduced in diameter, it is possible to prevent the bush from becoming smaller than the inner diameter at the axial center side. As a result, the interference of the inner diameter of the reduced diameter portion with respect to the outer diameter of the rotary shaft can be set small, and the fluid is filled in the annular space and pressurized to reduce the thin portion of the bush, thereby rotating the rotary tool. The effect of sticking to the surface is not impaired. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a partially cutaway front view in the II direction of FIG. 2 showing a woodworking cylinder according to one embodiment of the present invention. Fig. 2 is a partial cross-sectional view taken along the line II-II shown in Fig. 1. BEST MODE FOR CARRYING OUT THE INVENTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 and FIG. 2 show a partially broken woodworking cylinder as an example of a rotary tool according to the embodiment. (I-I direction of Fig. 1) and a partially broken cross-sectional view (II-II direction of Fig. 1). The woodworking cylinder 10 is provided with a cylindrical tool body 11 made of aluminum alloy, and is provided with a center hole 12 penetrating between both ends at the axial center position. On the outer peripheral surface of the tool body 11, four flat blade mounting grooves 13a to 13d for mounting flat blades extending in parallel in both axial directions are provided at equal intervals in the circumferential direction. The flat blade mounting groove 13a (13b to 13d has the same shape, and 13a will be described below) is inclined toward the radially rearward rotation side of the tool body 11 The rotation front side surface 13a1 and the rear side surface 13a2 are parallel to each other. The flat blade mounting groove 13a is slightly deeper in the vicinity of the rotation rear side surface 13a2.

 A flat blade 14 and a backrest 15 are mounted in the flat blade mounting groove 13a-13d. The flat blade 14 is a long plate having the same length as the flat blade mounting groove 13a, and a blade made of high-speed tool steel is fixed to the end by brazing. The backrest 15 is a substantially square pole-shaped rod of the same length as the flat blade mounting groove 13a, and one side 15a is a flat surface that is in close contact with the flat blade 14, and the opposite. The side surface 15b is provided with a recess 15c to which the screw 16 is brought into contact. The tool body 11 is provided with a screw hole 16a into which a screw 16 penetrating from the outer periphery to the flat blade mounting groove 13a is screwed. The flat blade 14 and the backrest 15 are flat blade 14 pressed against the side surface 13 a 2 of the flat blade mounting groove 13 a and screwed into the screw hole 16 a of the tool body 11 The screw 16 is fixed in the flat blade mounting groove 13a by firmly abutting the recess 15c of the backing 15 with the screw 16.

In the vicinity of the flat blade mounting groove 13 a of the tool body 11, two through holes of approximately 13 length in the axial direction penetrate radially from the outer peripheral surface and pass through the center hole 12. 17a and 18a are provided. An injection valve 17 is buried in the through hole 17a, and a stopper 18 is buried in the through hole 18a. The injection valve 17 is for injecting a high-pressure fluid from outside into the annular spaces 24 a and 25 a described later. The stopcock 18 opens while maintaining the high pressure in the annular space. Releasing the pressure reduces the pressure in the annular space.

 An annular bush 20 made of iron is fitted into the center hole 12 of the tool body 11, and both ends thereof project slightly outward from the center hole 12. The bush 20 has thick fixed portions 21 and 22 at the axial length of approximately 1 to 5 at both ends, and the axial length of approximately 1 to 5 at the axial center is thick. The portion of approximately 1 Z5 in the axial direction between the central portion 23 of the meat and the two fixed portions 21 and 22 and the central portion 23 becomes the thinned diameter reduced portions 24 and 25. ing. The wall thickness of the reduced diameter portions 24 and 25 is in the range of 1.5 to 3.5 mm, preferably 2 to 3 mm. Then, annular spaces 24 a and 25 a are formed between the reduced diameter portions 24 and 25 and the center hole 12. Ring mounting grooves 2 la and 22 a are coaxially provided near the inner ends in the axial direction of the fixing portions 21 and 22, and O-rings 21 b and 22 b are mounted inside thereof. Have been. The central portion 23 has an outer diameter slightly smaller than the outer diameter of the fixing portion, and has an annular gap 23 a between the inner peripheral surface of the tool body 11 and the fluid. Is provided.

 On the inner peripheral surface side of the bush 20, large-diameter portions 26a and 26b are formed between both ends and a position slightly inward in the axial direction from the outer ends of the reduced-diameter portions 24 and 25. The central portion 23 also has a large diameter portion 27 at the axially intermediate portion. The portions sandwiched between the large diameter portions 26a and 26b and the large diameter portion 27 are small diameter portions 28a and 28b slightly smaller in diameter than the large diameter portion. The difference in inner diameter between the large diameter part and the small diameter part is about 0.1 mm.

 The woodworking cylinder 10 is formed by heating the tool body 11 to a predetermined temperature, while applying an adhesive to the fixing portions 21 and 22 of the bush 20 and forming a ring for the ring. Rings 2 1 b and 22 b are mounted on 2 la and 22 a, and bush 20 is inserted into the center hole 12 of the heated tool body 11 and cooled. This results in a shrink fit.

In this way, push 20 into the center hole 12 of the heated tool body 11 Only by fitting, the bush 20 can be easily and uniformly fixed to both ends of the center hole 12 of the tool body 11 by shrink fitting. In the shrink fitting, a large number of tool bodies 11 are heated and sequentially taken out, and a bushing 20 is fitted into the center hole 12 thereof to form a continuous plane cylinder. Can be. In addition, by applying an adhesive to the fixing portions 21 and 22 of the bush 20, the shrink fit is performed more firmly.

 With the rotary shaft 31 of the plane cylinder drive machine fitted in the center hole 12 of the plane cylinder 10 into which the bush 20 is inserted, the annular space 24 from the injection valve 17 is inserted. The plane cylinder 10 is tightly fixed to the rotating shaft 31 by filling a fluid such as grease in a and pressurizing the same to reduce the diameter of the thin reduced diameter portions 24 and 25 of the bush 20. When the fluid is filled and pressurized, radial pressure is applied to the reduced diameter portions 24 and 25, and pressure is also applied to the fixed portions 21 and 22 in the axial direction. It tries to extend unevenly in the axial direction. However, since the fixing parts 21 and 22 are firmly fixed to the tool body 11 with the effect of the adhesive, the reduced diameter parts 24 and 25 Axial extension can be prevented. Therefore, delicate bending of the rotating shaft 31 due to the extension of the reduced diameter portions 24 and 25 can be suppressed, and a decrease in the rotating accuracy of the rotating shaft 31 can be prevented.

 In the bush 20, since the inner diameters of the fixing portions 21 and 22 on both ends in the axial direction are larger than the inner diameters of the reduced diameter portions 24 and 25 on the center side, the bush 20 is formed by the tool body. Even if the fixed portions 21 and 22 are reduced in diameter by shrink fitting to 11, the inner diameter of the reduced diameter portions 24 and 25 does not become smaller. Therefore, the interference of the inner diameters of the reduced diameter portions 24 and 25 with respect to the outer diameter of the rotating shaft 31 can be set to be small, and the fluid is sealed in the annular space portions 24a and 25a and pressurized to reduce the diameter. By reducing the diameter of 24 and 25, the effect of fixing the plane cylinder 10 to the rotating shaft 31 is not impaired.

In the above embodiment, the adhesive is applied to the fixing portion, The adhesive can be omitted if necessary. Also, the 0 ring attached to the fixing portion can be omitted as necessary. Further, in the above-described embodiment, shrink fit is performed in which the bush is fitted to the tool body while the tool body is heated. Alternatively, the tool body is cooled and the bush is cooled. A cold fit may be inserted into the heated bush, or both may be used in combination, and a cooled bush may be fitted over the heated tool body. In addition, what is shown in the above embodiment is an example, and various changes can be made without departing from the gist of the present invention.

Industrial applicability

 The rotating tool according to the present invention is suitable for use as a wood planer cylinder fixed to a rotating shaft via a bush, and is useful for cutting with high rotational accuracy.

Claims

The scope of the claims 1. In the center hole of the cylindrical tool body, a thin cylindrical bush that can be reduced in diameter at least partially in the axial middle is inserted.  The bush is in liquid-tight contact with the center hole at both end sides of the tool body, and has an annular space between the center hole at the axially intermediate portion of the tool body, With the rotary shaft inserted into the center hole through the bush, a fluid is sealed in the annular space and pressurized to reduce the diameter of the thin portion of the bush, thereby being fixed to the rotary shaft. A rotary tool, wherein the bush is fixed at both ends of a center hole of the tool body by shrink fit or cold fit or a combination thereof. 2. The rotary tool according to claim 1, wherein the bush is shrink-fitted, cold-fitted, or used together with an adhesive in a center hole of the tool main body.  3. The rotary tool according to claim 1, wherein the bush has an inner diameter at both ends in the axial direction larger than an inner diameter of the thin portion.