CUTTING TOOL DEVICE FOR MACHINE TOOL

Abstract: A cutting tool device for a machine tool having a cutting tool (2) for cutting a plane fixed to the tip end of a rotating shaft (1) and provided with a suction cover (10) covering airtightly the surrounding portions except for a tip face (a), of the cutting tool (2), wherein a hood (19) is attached to the tip opening edge of the suction cover (10) so as to further extend forward therefrom and to be displaceable longitudinally within a limited range, and an urging means (24) for urging the hood (19) forward is provided, whereby chips (w1) produced by the cutting tool (2) can be positively sucked and discharged when the tool is used in any of a roughing step and a finishing step.

Description: FILED OF THE INVENTION The present invention relates to a cutting tool device of a machine tool according to the preamble of claim 1 and as known from EP-B-0397193. BACKGROUND OF THE INVENTION The Japanese patent No. 2535964, for example, discloses a cutting tool device of a machine tool having a fraise cutter fixed to the tip of a rotating shaft and provided with a suction cover covering the surrounding portions, except for the tip face, of the cutter. This cutting tool device moves in a direction cross to the rotating shaft during use. The fraise cutter machines a work surface of a work in a plane during its movement. On the other hand, air inside the suction cover is attracted by an air suction device prepared separately and is eliminated in the other place. Because of this elimination, an air flow generated around the fraise cutter acts that chips produced by machining of the fraise cutter may be continuously discharged to the other place. In the above machine tool, plural kinds of cutting tool device, in each of which a longitudinal distance between the tip face of the fraise cutter and the tip face of the suction cover is suitably changed, are usually prepared on each machining step such as a roughing step and a finishing step in relation to an uneven size of the work surface and the amount of cuts per 1-time cutting. These cutting tool devices are used so that exchange installing may be carried out in each machining step to the cutting end of the work. The above-described conventional cutting tool device is uneconomical in preparing different cutting tool device for each machining step of the work. Besides, these devices need to be exchanged during machining the work, thereby taking more time as well as having disadvantage in keeping cutting accuracy. An object of this invention, therefore, is to propose a cutting tool device for a machine tool that can overcome the above problems. SUMMARY OF THE INVENTION To achieve the above objects, as described in claim 1, the present invention comprises a cutting tool for cutting a plane fixed to the tip of a rotating shaft, and a suction cover covering airtightly surrounding portions, except for the tip face of the cutting tool, wherein a sleeve is attached to the tip opening edge of the suction cover so as to further extend forward therefrom. Here, the sleeve is formed in L letter cross section, and the tip of a horizontal part thereof is made to go toward the cutting tool. Besides, the horizontal part is defined to be variable restriction to be rockable longitudinally in a limited angle of inclination. According to this structure, the sleeve retreats upon touch with an uneven work surface of a work without disturbing a cutting step. The tip face of the sleeve can come very close to the uneven face during not only a finishing step but also a roughing step without arranging its position. Because of the effect of this sleeve, one cutting tool device can be utilized both in a roughing step and a finishing step. The present invention has concrete structures as follows. As shown in claim 2, when the sleeve is located at a front restricted position in its longitudinal displaceable range, the tip face of the sleeve is defined so as to be set apart from the tip face of the cutting tool for about 0.5 mm ∼ 3.0 mm backward. According to this structure, the cutting tool device can be intactly utilized in both a practical roughing process and a practical finishing process. Besides, as shown in claim 3, the front restricted position of the sleeve in the longitudinal displaceable range can be changed. According to this structure, the sleeve can always act on a variety of works having different uneven faces and any amount of cuts per 1-time cutting in the best condition. Moreover, as shown in claim 5, the horizontal part of the sleeve is tapered outwardly along its radius direction. According to this structure, when the horizontal part of the sleeve contacts the uneven work surface, the sleeve stops being caught easily unevenly, and can receive great upward force smoothly, thereby enabling high quality cutting. Furthermore, as shown in claim 8, the rotating shaft, the cutting tool, the suction cover, the sleeve and a variable device are formed into an independent integral structure object, which is detachable from a main spindle of the machine tool. According to this structure, the cutting tool device can be easily exchanged with another one, and its desorption is carried out by an automatic cutting tool device exchanging machine. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side perspective view showing a part of a cutting tool device of a machine tool according to this invention. FIG. 2 is a partially front view of a cutting tool in the above-mentioned. FIG. 3 is an explanatory view showing the actions of the above cutting tool device: FIG. 3A shows a state right before a machining process starts, FIG. 3B shows the surrounding portions of the front end side in main spindle travelling direction of a sleeve during machining, and FIG. 3C shows the surrounding portions of the back end side in main spindle travelling direction of the sleeve during machining. DESCRIPTION OF PREFERRED EMBODIMENTS Fig. 1 is a side perspective view showing a part of a cutting tool device of a machine tool according to this invention. Fig. 2 is a front view of the above cutting tool device. Fig. 3 is an explanatory view showing the actions of the above cutting tool device. First, the cutting tool device is described in detail. Numeral 1 is an arbor of a rotating shaft. The arbor 1 includes a parallel body 1a, on the front-end face of which is provided a protruding portion 1b having a round section, on the periphery of the front end of which is provided male screw 1c, and on the back end of which is provided the first flange 1d. Besides, the second flange 1f is provided on the back of the first flange 1d through a parallel body 1e, and a taper shank 1g is provided at the back thereof. Moreover, a pulling stud 1h protruding backward is provided on the back-end face of the taper shank 1g. In this case, 1i is a circular groove body having a trapezoid section provided in the longitudinal middle of the second flange 1f, which is gripped by a tool-exchanging machine not shown. Numeral 2 is a fraise cutter as a cutting tool for cutting a plane, comprising a stepped cylindrical cutter body 2a, on an outer circumference of the tip face a of which are longitudinally fixed at limited intervals in circumferential direction chips 3 being square in a side view, at the center of which is provided a stepped internal hole 2b, and on the back face of which is provided an interfitted indentation 2c to receive a detent key 4 fixed on the tip face of the parallel body 1a of the arbor 1. Here, as shown in Fig. 3A, a front edge of the cutter body 2a serves as a front cutting edge 3a of the chip 3, whereas a side edge thereof serves as a side cutting edge 3b thereof. The fraise cutter 2 is fixed to the tip of the arbor 1 in the following manner. The aftermost part of the internal hole 2b of the cutter body 2a is externally engaged with the protruding body 1b of the arbor 1, and the detent key 4 fixed on the tip face of the arbor 1 is internally engaged with the interfitted indentation 2c. Besides, a flanged bush 5 is internally engaged with a middle part of the internal hole 2b of the cutter body 2a, and a fixing bolt 6 is inserted into an inner hole of the bush 5. Then, a threaded portion of the bolt 6 is screwed into female screw formed on the protruding body 1b of the arbor 1. Numerals 7a, 7b are a pair of front and back ball bearings outwardly provided to the parallel body 1a of the arbor 1. A back-end face of an inner ring for the back ball bearing 7b is engaged with the first flange 1d, whereas a front-end face of an inner ring for the front ball bearing 7a is pressed against a nut 8 screwed to the male screw 1c of the parallel body 1a through a spacer ring and a circular plate 9. Thus, longitudinal positions of the ball bearings 7a, 7b for the arbor 1 are restricted. Besides, the circular plate 9 is to prevent the nut 8 from being loosened. Numeral 10 is a suction cover, comprising a stepped cylindrical body 10a and a suction passage 10b. The stepped cylindrical body 10a covers airtightly the surrounding portions, except for the tip face a, of the fraise cutter 2, and the suction passage 10b extends backward so as to protrude sideways from a part of the periphery of the cylindrical body 10a. The cylindrical body 10a includes a base body b1 having an inner hole which is externally engaged with the ball bearings 7a, 7b, and a head body b2 having an inner hole of relatively large diameter for encircling the fraise cutter 2. A back circular secure plate 11 is bolted to the back face of the base body b1 to prevent forward displacement of the suction cover 10 for an outer ring of the back ball bearing 2b by means of protruding inward of its inner hole. Besides, a front circular secure plate 12 is bolted to a marginal step between the inner hole of the base body b1 and the inner hole of the head body b2 to prevent backward displacement of the suction cover 10 for the front face of the nut 8. Moreover, a sealing means 13 is provided to seal airtightly the intermediate between the circular secure plate 12 and the cutter body 2a. The above suction passage 10b is provided with a suction pass c which communicates with the inner hole of the head body b2. The suction pass c is led sideways from a portion c1 communicating with the inner hole of the head body b2, continuously led backward, whereupon being open to a protruding face d which extends the back face of the base body b1 sideways. A connector 14 is fixed to the back end of the suction pass c, and then a circular sealing member 15 is fitted to a back edge of the connector 14. A detent means for the suction cover 10 is provided between the connector 14 and the back circular secure plate 11 on the protruding face d. The detent means comprises a guiding hole e formed on the protruding face d, a sliding shaft 16 inserted into the guiding hole e, and a compressed spring 17 provided between the sliding shaft 16 and the bottom of the guiding hole e. Besides, an engaging plate 16a and a cap 18 are bolted to the tip of the sliding shaft 16. Moreover, the outer end of the engaging plate 16a is engaged with a vertical groove f formed on the outer periphery of the connector 14, whereas the inner end of the engaging plate 16a is engaged with a vertical groove g formed on the circular groove body 1i of the second flange 1f. Here, an explanation follows concerning the action of the engaging plate 16a. When the engaging plate 16a is free, the sliding shaft 16 is pushed backward by the compressed spring 17. This backward movement is restricted by an interaction between the outer end of the engaging plate 16a and the back end of the vertical groove f. In this state, the inner end of the engaging plate 16a is located at the upper end of the vertical groove g, thereby restricting rotations of the arbor 1. However, if the sliding shaft 16 is pushed forward for a limited distance by some other means, the inner end of the engaging plate 16a is located in the circular groove body 1g, thereby releasing the arbor 1 to rotate. Next, an explanation follows concerning the characteristic construction of this invention. A sleeve 19 having L letter cross section as a hood is attached to the tip opening edge of the above suction cover 10 so as to extend further forward therefrom and to be rockable longitudinally in a limited angle of inclination. More concretely, a circular guiding groove h is provided to the tip opening edge of the suction cover 10, and a vertical part of the sleeve 19 is inserted into the guiding groove h so that the horizontal part can go toward the cutting tool. Besides, a variable device 20 to be rockable longitudinally is defined as follows. That is to say, the variable device 20 comprises a nut 21 engaged with a male screw i formed on the outer periphery of the vertical part of the tip opening edge of the suction cover 10, and engaging pieces 22 bolted on the front-end face of the nut 21 at fixed intervals in its circumferential direction. The tip of each engaging piece 22 is engaged with a circular groove j of a limited width provided on the outer periphery of the sleeve 19. Hence, fixing screws 23 are provided to the thickness of the nut 21 at fixed intervals in its circumferential direction to fix the nut 21 at a suitable position on the male screw i. On one hand, an urging means is provided so as to urge the sleeve 19 forward. Concretely, compressed springs 24 are provided between the vertical part of the sleeve 19 in the guiding groove h and the bottom face thereof at fixed intervals in a circumferential direction of the guiding groove h. These compressed springs 24 act so that the horizontal part of the sleeve 19 is displaced toward the cutting tool with their spring effect. When the sleeve 19 is free, they act so as to keep the sleeve 19 at the front restricted position in its rocking range with pushing a back wall k1 (in Fig. 3) of the circular groove j to the whole engaging pieces 22 of the nut 21 fixed on suitable position on the male screw i. On the other hand, a tip face m of the horizontal part of the sleeve 19 is tapered outwardly in a radius direction thereof. When the sleeve 19 is located at the front restricted position, the tip face m of the horizontal part of the sleeve 19 is set apart from the tip face a of the fraise cutter 2 for about 0.5 mm ~ 3.0 mm. The cutting tool device has thus described construction. Each component is connected with each other to form integral structure. Next, a main spindle for installing on the above cutting tool device will be explained with reference to Fig. 1 as follows. Numeral 100 is a main spindle supporting member, 101 is a main spindle rotatably supported by the main spindle supporting member 100 through ball bearings 102a, 102b, and 103 is a front circular member bolted to a tip face of the main spindle supporting member 100. Numeral 104 is a circular-covering member externally fixed to the tip of the main spindle 101 of small diameter to cover a space between the main spindle 101 and the front circular member 103. Numeral 105 is a protruding supporting member bolted to a front face of the front circular member 103 so as to keep away from the circular-covering member 104. As shown in Fig. 2, a pair of forward protruding bodies n1, n2 are provided on the forward main spindle 101 side of the protruding supporting member 105. The protruding bodies n1, n2 are located at places shown in oblique lines, having the cap 18 therebetween. A suction opening c2 is provided outside the protruding bodies n1, n2, in correspondence with the connector 14. To the back end of the suction opening c2 is connected one end of an air suction pipe 106. Besides, the other end of the air suction pipe 106 is connected to a not-illustrated air suction device. Next, an explanation follows concerning use and actions of the above cutting tool device. The above cutting tool device is placed on a storage stand, for example, in a fixed posture, when it is not used. On installing the cutting tool device to the machine tool, the cutting tool device is carried before the main spindle 101 by a not-illustrated tool exchanger, and then the taper shank 1g is pushed into a center hole of the main spindle 101, as shown in Fig. 1. Next, the pull stud 1h is pulled backward by a not-illustrated drawing mechanism. In consequence, the arbor 1 is fixed to the main spindle 101 firmly, and the cutting tool device is perfectly fixed to a working position. In this state, an inner hole of the connector 14 is connected with the suction opening c2 of the protruding supporting member 105 airtightly through the circular-sealing member 15. The cap 18 for preventing rotations of the suction cover 10 is interfitted between a pair of the protruding bodies n1 and n2, and pushed forward for a limited distance against the compressed spring 17. In consequence, the suction cover 10 is fixed, being restricted from its rotation around the main spindle 101. Besides, the inner end of the engaging plate 16a is located in the circular groove body 1 i, thereby releasing the arbor 1 to rotate around the center of the main spindle 101. To detach the cutting tool device from the working position and return it to the storage stand, reverse actions are carried out. Cutting a work w with the cutting tool device fixed in a state shown in Fig. 1 is carried out in the following manner, for example. The work w is fixed on a not-illustrated working table, and the not-illustrated air suction device is operated. Then, the main spindle is rotated. Next, as shown in Fig. 3A, the main spindle 101 is moved forward to a suitable position so that the fraise cutter 2 can cut the work at a fixed height. Then, the main spindle 101 is rectilinearly displaced in a direction u perpendicular thereto. As shown in Fig. 3B, the fraise cutter 2 cuts the work w flatly with the front cutting edge 3a and the side cutting edge 3b thereof, while it is moving on. During this process, chips w1 are continuously produced. On the other hand, the air pass c and chip discharging space p between the fraise cutter 2 and the suction cover 10 are made into a vacuum. Accordingly, the air bursts into the chip discharging space p through an opening between the tip face m of the sleeve 19 and a work surface s of the work w. This inflow of the air continuously discharges the chips w1 produced by the fraise cutter 2 into some other place through the chip discharging space p, the air suction pass c, and the air suction pipe 106. The longitudinally movements of the sleeve 19 is restricted by an annular groove j thereof. Since its front restricted position is relatively low in relative to irregularities of the work surface s in the roughing step, a part 19a of the tip face m of the sleeve 19 is in contact with convexities of uncut surface s1. Here, the part 19a is before the main spindle moving in its progressive direction. The uncut surface s1 gives boosting force to the tip face m of the sleeve 19, and therefore the part 19a of the sleeve 19 is pushed back against the compressed spring 24. On the other hand, as shown in Fig. 3C, a part 19b of the sleeve 19 remains in the front restricted position without contacting with a cut surface s2 after the main spindle moving in its progressive direction. The sleeve 19 moves in the direction u perpendicular to the main spindle, being in an inclined and retreated state. Accordingly, the sleeve 19 can move with the spindle 101 and the suction cover 10 without being caught by the work surface s of the work with keeping the distance with it small. When the distance between the tip face m of the sleeve 19 and the work surface s is small, inflow speed of the air into the suction cover 10 and discharge capacity of the chip w1 are increased. Besides, since the tip face m of the sleeve 19 is tapered outwardly in a radius direction thereof, the sleeve 19 can move smoothly in keeping touch with the convexities. Accordingly, an overlap thereof is evaded more certainly. During a finishing process, since the irregularity of the work surface s and an amount of cuts per 1-time cutting are small, the sleeve 19 can move forward with the spindle 101 and the suction cover 10, generally without contacting with the work surface s. However, as described in the above, since the restricted position of the sleeve 19 by the annular groove j is relatively low in relative to the work surface s, the sleeve 19 can keep the distance with the work surface s small during this process. If there is an unexpected large convex on the work surface s, the sleeve 19 is inclined and retreated according to the roughing process. Accordingly, the distance between the sleeve 19 and the work surface of the work w is maintained as small as possible, thereby increasing inflow speed of the air into the suction cover 10 as well as discharge capacity of the chips. It may be necessary to change the front restricted position of the sleeve 19 by the annular groove j according to degree of the uneven work surface s of the work w or an amount of cuts per 1-time cutting of the fraise cutter 2. In this case, the fixing screw 23 is operated to change a longitudinal position of the nut 21 on the male screw i. In the above embodiment, a sectional form of the passage of the sleeve 19 is not restricted to a complete round, but it can be a suitable form. Besides, a plate spring or a folded linear spring, or even a fluid pressure utilizing means can be used as an urging means instead of the spring 24. Moreover, a milling cutter or an end mill cutter can be used as a cutting tool for cutting a plane instead of the fraise cutter 2. According to thus constructed invention, the chips can be effectively discharged during both the roughing step and the finishing step. Therefore, it is unnecessary to prepare different mechanisms for each machining step, which is very economical. Besides, since it is unnecessary to change the cutting tools when moving into the next machining step, time for treatment is shortened and working efficiency increases remarkably. Moreover, it can be prevented to decrease accuracy due to exchanging the cutting edges. Furthermore, since the hood is contacted between the uncut surface and the cut surface of the work in a rockable inclined state, a space between the tip face of the hood and the work surface of the work becomes small. Accordingly, recovery percentage of the chips during a roughing step, for example, can be increased up to 95 %. According to the claim 2, the present invention can be conveniently utilized in most of usual roughing and finishing processes. According to the claim 3, the present invention can have suitable suction capacity of the chips for any work having a different uneven work surface or for a broad machining requiring different an amount of cuts per 1-time cutting. According to the claim 5, the tip face of the sleeve receives great upward force smoothly by touching the uneven work surface of the work, thereby ensuring its retreat as well as its prevention from being caught by the uneven work surface. Besides, when the sleeve moves on the work, there hardly arise vibrations due to their contact, thereby effecting a cut of high quality. According to the claim 8, other cutting tool device can be applied to the present invention. Besides, the present invention can contribute to forming a detachable structure by an automatic tool-exchanging device.

Claims: A cutting tool device for a machine tool comprising: a cutting tool (2) for cutting a plane fixed to a tip end of a rotating shaft (1); and a suction cover (10) covering airtightly surrounding portions, except for a tip face (a) of the cutting tool, (2) characterized in that a sleeve (19) is attached to a tip opening edge of the suction cover (10) so as to extend further forward therefrom to be displaceable longitudinally within a limited range, and an urging means (24) for urging the sleeve (19) forward is provided. A cutting tool device for machine tool as set forth in claim 1: wherein a tip face of the sleeve (19) is set apart from the tip face of the cutting tool (2) for about 0.5 mm ∼ 3.0 mm backward, when the sleeve (19) is located at a front restricted position in its longitudinal displaceable range. A cutting tool device for machine tool as set forth in claim 1: wherein the front restricted position of the sleeve (19) in the longitudinal displaceable range can be changed. A cutting tool device for machine tool as set forth in claim 2: wherein the front restricted position of the sleeve (19) in the longitudinal displaceable range can be changed. A cutting tool device for machine tool as set forth in claim 1: wherein the tip face of the sleeve (19) is tapered outwardly along its radius direction. A cutting tool device for machine tool as set forth in claim 2: wherein the tip face of the sleeve (19) is tapered outwardly along its radius direction. A cutting tool device for machine tool as set forth in claim 3: wherein the tip face of the sleeve (19) is tapered outwardly along its radius direction. A cutting tool device for machine tool as set forth in claim 1: wherein the rotating shaft (1); the cutting tool (2); the suction cover (10); the sleeve (19); and the urging means (24) are integrated into one independent structural object; and wherein said structural object is detachable from a main spindle of the machine tool. A cutting tool device for machine tool as set forth in claim 3: wherein the rotating shaft (1), the cutting tool (2), the suction cover (10), the sleeve (19), and the urging means (24) are integrated into one independent structural object; and wherein said structural object is detachable from a main spindle of the machine tool. A cutting tool device for machine tool as set forth in claim 5: wherein the rotating shaft (1), the cutting tool (2), the suction cover (10), the sleeve (19), and the urging means (24) are integrated into one independent structural object; and wherein said structural object is detachable from a main spindle of the machine tool.

Inventors: SUGATA SHINSUKE, YOSHIMURA KAZUTAKA, SUGATA, SHINSUKE, YOSHIMURA, KAZUTAKA
Applicants: HORKOS CORP
Application year: 1999
Main classification: B23Q11
IPC codes: B23Q11, B23C5, B23C9