JP4057863B2 - Deep hole cutting equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a deep hole cutting apparatus that discharges chips generated during cutting to the outside through a hollow boring bar together with coolant from a discharge port provided in a boring head.
[0002]
[Prior art]
In general, the cutting efficiency of deep hole machining is more dependent on the capability of discharging chips generated inside the cutting hole during machining to the outside than the capability of the tool system. For this reason, in the deep hole cutting apparatus, a hollow boring bar is used, a discharge port that opens from the top surface to the peripheral surface is provided at the top of the boring head, and the discharge port is provided with coolant that is supplied to the cutting blade. From the inside of the boring bar to the outside. Therefore, as a boring head applied to deep hole cutting with a relatively large cutting hole diameter, a plurality of cutting blades responsible for cutting each part of the cutting area from the central part to the peripheral part of the cutting hole are used. There is one in which the cutting blades are distributed and attached to the opening side edges of the two large and small discharge ports.
[0003]
4 (a) and 4 (b) show a general boring head 30 having three cutting edges, which is used in a conventional deep hole cutting apparatus. The boring head 30 has a substantially cylindrical shape having a hollow portion 31 opened on the base end side, and has a large and small discharge ports 33 and 34 communicating with the hollow portion 31 at the top portion 32, and has a substantially obtuse cone shape. A central cutting edge 41 and a peripheral cutting edge 42 are attached to the opening side edge 33a of the large discharge port 33 that opens in a fan shape facing the top surface 30a of the main body, and a substantially trapezoidal shape in which a part of the fan shape is also missing. An intermediate cutting edge 43 is attached to the opening side edge 34a of the small discharge port 34 that is open to the center. Both the discharge ports 33 and 34 are set to have an opening area ratio of about 2: 1, and are opened in a rectangular shape on the outer peripheral surface 30b side with the opening lower edges 33b and 34b at the same position. Further, guide pads 51, 52 made of super hard material are attached to the outer peripheral surface 30b between the discharge ports 33, 34, and the heads at the mounting positions of the guide pads 51, 52 and the peripheral cutting blade 42 are attached. On the rear side in the rotational direction, bulging portions 35a to 35c having a larger radius and a narrower width than other peripheral surface regions are provided in order to receive a load applied to these members 51, 52, and 42 during the cutting process.
[0004]
In such a boring head 30, a base portion 36 having a male screw 36a on the outer periphery is screwed into and attached to a tip portion of a hollow boring bar 60 indicated by a phantom line in FIG. 4B, and the boring bar 60 is attached to a machine tool. The cutting material is cut by the cutting edges 41 to 43 to form a deep hole by being connected to a driving shaft such as a spindle of the above and rotating it or rotating the material side. The relative direction of rotation of boring head 30 is a counterclockwise direction in FIG. 4 (b). During the cutting process, coolant is supplied from the opening of the cutting hole through the gap between the cutting hole and the boring bar 60 to the cutting blade side at a high pressure, and both the boring head 30 is discharged together with the chips that generate the coolant. It flows into the hollow portion 31 from the outlets 33 and 34 and is discharged to the outside through the hollow boring bar 60.
[0005]
[Problems to be solved by the invention]
However, in the cutting process by the conventional boring head 30, the chip discharge performance on the small discharge port 34 side of the two large and small discharge ports 33, 34 tends to be deteriorated, and therefore the cutting efficiency is lowered. At the same time, the small discharge port 34 is often clogged, making it impossible to cut.
[0006]
Therefore, the present inventors investigated the cause of the poor chip discharge performance on the small discharge port side in this type of conventional boring head. In addition to the poor passage, it was found that the coolant flow at the top of the boring head was structurally significantly biased toward the large outlet, and the amount of coolant flowing into the small outlet was insufficient. For example, in the boring head 30 shown in FIGS. 4 (a) and 4 (b), the coolant that has been sent to the cutting edge flows evenly over the entire circumference up to the front of the top 32, but in the top 32 is close to the inner periphery of the cutting hole. The flow is divided in the form of being partitioned by the three bulging portions 35a to 35c, and flows into the discharge ports 33 and 34. At this time, the large discharge port 33 having a large opening area has a small flow resistance, and the coolant flows into the large discharge port 33 through a wide circumferential width range from the peripheral cutting edge 42 to the protruding portion 35a. On the other hand, the coolant flow area to the small discharge port 34 with a small opening area and a large flow resistance has a narrow circumferential width between the protruding portion 35b and the guide pad 51, and therefore the ratio of the opening areas of the discharge ports 33 and 34 to each other. The actual coolant inflow amount was biased from 3: 1 to 5: 1 with respect to 2: 1.
[0007]
The present invention provides a boring head based on the above knowledge as a deep hole cutting device that discharges chips generated during cutting from the two large and small discharge ports of the boring head together with coolant to the outside through the hollow boring bar. By making an appropriate improvement to the above, it is possible to provide a chip that has excellent chip discharge performance and high cutting efficiency, and can reliably avoid inability to cut due to clogging on the small discharge port side.
[0008]
[Means for Solving the Problems]
That is, according to the first aspect of the present invention, the reference numeral of the drawing is attached, and the top portion 21 of the boring head 2 provided at the tip of the hollow boring bar 1 is opened from the top surface 2a to the outer peripheral surface 2b. Two large and small discharge ports 3 and 4 communicating with the inside of the boring bar 1 and cutting edges 5a to 5c attached to the opening side edges 3a and 4a facing the boring head top surface 2a of the respective discharge ports 3 and 4 are provided. The coolant C supplied to the cutting edge through the flow gap between the outer peripheral surface 2b of the boring head 2 and the inner peripheral surface of the cutting hole H together with the chips S generated by the cutting is supplied to both the discharge ports 3 and 4. In the deep hole cutting apparatus that flows in and discharges to the outside through the inside of the boring bar 1, the ratio of the coolant inflow amount to both the discharge ports 3 and 4 is the same as the opening area ratio of both the discharge ports 3 and 4, or small discharge The inflow to the outlet 4 is As will be greater rate than the mouth area ratio, Ri name by setting the flow gap, in order to set the flow through the gap, on both sides that Wakata by the two outlet 3,4 at the top 21 of the boring head 2 On the outer peripheral surfaces 21a and 21b, a bulging portion 7 is formed that narrows the flow gap more than the outer peripheral portion (intermediate portion 23) along the lower opening edges 3c and 4d of both the discharge ports 3 and 4, The flow gap is set by the presence or absence or size of the non-bulged portion 8 extending in the circumferential direction from each of the four, and the ratio of the coolant inflow amount is thereby set.
[0009]
According to a second aspect of the present invention, in the deep hole cutting apparatus according to the first aspect, the flow gap is set so that the coolant inflow amount to the small discharge port 4 is equal to or less than the coolant inflow amount to the large discharge port 3. Is adopted.
[0010]
According to a third aspect of the present invention, in the deep hole cutting device according to the first aspect , the guide does not have the non-bulged portion 8 continuing from the large discharge port 3 in the circumferential direction, and is guided from the small discharge port 4 to the rear side in the head rotation direction. It is assumed that it has a non-bulged portion 8 that continues to the pad 6a mounting position.
[0011]
According to a fourth aspect of the present invention, in the deep hole cutting apparatus according to any one of the first to third aspects, the central cutting edge 5a and the peripheral cutting edge 5b are attached to the large discharge port 3 side, and the small discharge port 4 is attached. The intermediate cutting edge 5c is attached to the side, the opening area ratio of both the discharge ports 3 and 4 is approximately 2: 1, and the ratio of the coolant inflow rate of the large discharge port / small discharge port is 2/1 to 1 / 1 is set.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a deep hole cutting apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings. FIGS. 1A and 1B are boring heads used in the deep hole cutting apparatus, FIG. 2 is a cutting state by the deep hole cutting apparatus, and FIG. 3 is a top end portion of the boring head during the cutting process.
[0013]
The boring head 2 shown in FIGS. 1 (a) and 1 (b) has a substantially cylindrical shape having a hollow portion 20 opened on the base end side, and has a large and small 2 opening from the top surface 2a of the substantially obtuse conical shape to the peripheral surface 2b. A top portion 21 having two discharge ports 3 and 4 and three cutting blades 5a to 5c, a base portion 22 provided with a male screw 22a on the outer periphery, and between the opening lower edges 3c and 4d of both discharge ports 3 and 4 to the base portion 22 It comprises an intermediate part 23, and as shown in FIG. 2, the base part 22 is screwed into the tip part of the hollow boring bar 1 and attached.
[0014]
Both the discharge ports 3 and 4 are arranged substantially opposite to each other in the radial direction of the boring head 2, and the outer peripheral surfaces 21 a and 21 b separated by the both discharge ports 3 and 4 at the top portion 21 are respectively made of cemented carbide. The guide pads 6a and 6b made of metal are attached in a partially protruding state with an arrangement that is biased toward the small discharge port 4 side. The large discharge port 3 opens in a fan shape facing the top surface 2a, and a central cutting edge 5a and a peripheral cutting edge 5b are attached to an opening side edge 3a on one side thereof. On the other hand, the small discharge port 4 faces the top surface 2a and opens in a substantially trapezoidal shape with a part of a fan-shaped part cut off. The intermediate cutting blade 5c is attached. Further, both the discharge ports 3 and 4 are formed in a rectangular shape with the opening lower edges 3c and 4d at the same position on the outer peripheral surface 2b side of the boring head 2 so that the ratio of the entire opening area is approximately 2: 1. Is set to
[0015]
In this boring head 2, the entire intermediate portion 23 is set to have an outer diameter substantially equal to that of the boring bar 1, but the guide pad 6 a on the outer peripheral surface 21 a of the top portion 21 and the head rotation direction of the large discharge port 3 [ Figure 1 (a) between the the opening edge 3 b in the counterclockwise direction] front side, and the large radius of the bulging portion 7 becomes than the full width intermediate portion 23 of the outer peripheral surface 21b, the small discharge on the outer circumferential surface 21a only between the opening edge 4b and the guide pad 6a of the head rotation direction rear side in the outlet 4 is in the non-bulged portion 8 of the same radius and the intermediate portion 23.
[0016]
As shown in FIG. 2, the deep hole cutting apparatus has a boring head 2 having the above-described configuration attached to the distal end portion of a hollow boring bar 1 by screwing a base portion 22, and the boring bar 1 is inserted through a tool chuck not shown. Deep hole cutting is performed on the work material W by being connected to a spindle of a machine tool and driven to rotate. In this cutting process, a coolant supply jacket 10 that oil-tightly surrounds the boring bar 1 via a seal member 9 is used, and the introduction port 10a is in a state where the jacket 10 is pressed against the work material W via a seal ring 12. While introducing the higher pressure coolant C, the boring bar 1 is rotationally driven in the direction of arrow F in FIG. 2, that is, in the direction of increasing the degree of screwing with the boring head 2, and the boring head 2 is pressed against the work material W. Then, the workpiece W is cut with the cutting blades 5a to 5c to form the cutting hole H. The guide pads 6a and 6b perform a function of holding the boring head 2 concentrically with the cutting hole H by slidingly contacting the inner peripheral surface of the cutting hole H during the cutting process.
[0017]
Thus, the coolant C introduced into the jacket 10 is supplied to the boring head 2 side from the annular outlet 10b surrounding the boring bar 1 through the flow gap T between the cutting hole H being formed and the boring bar 1. Then, it flows into both the discharge ports 3 and 4 of the boring head 2 together with the chips S generated by the cutting, and is discharged to the outside through the inside 1 a of the boring bar 1. At this time, the supplied coolant C flows evenly over the entire circumference up to the intermediate part 23 of the boring head 2, but at the top part 21, the bulging parts 7, 7 come close to the inner circumference of the cutting hole H and the flow gap T Therefore, the amount passing between the bulging portions 7 and 7 and the inner periphery of the cutting hole H becomes extremely small, and the flow is divided in a form substantially partitioned by the bulging portions 7 and 7. It flows into both discharge ports 3 and 4. However, as shown in FIG. 3, only the circumferential width of the opening lower edge 3 c becomes the inflow region of the coolant C on the large discharge port 3 side, whereas the lower opening edge 4 d and the non-bulging on the small discharge port 4 side. The combined circumferential width, that is, the wide circumferential width from the opening side edge 4c on the front side in the head rotation direction to the guide pad 6a on the rear side is the inflow region of the coolant C.
[0018]
Therefore, the small discharge port 4 with a small opening area has poorer passage of the chips S and larger flow resistance of the coolant C than the large discharge port 3, but the inflow area on the large discharge port 3 side is larger than that of the conventional configuration. Since it is narrowed down significantly, the coolant inflow rate to the small discharge port 4 increases, and accordingly, the discharge of the chips S from the small discharge port 4 is promoted, and the small discharge port 4 In addition, it is possible to surely avoid a situation where cutting becomes impossible due to clogging of the chips S, and the flow passage cross-sectional area of the coolant C is greatly reduced as compared with the intermediate portion 23 as a whole, so both the discharge ports 3 , 4 also increases the inflow pressure of the coolant C, so that the efficiency of discharging the chips S from both the discharge ports 3 and 4 increases, leading to an improvement in cutting efficiency. In addition, although the opening area ratio of both the discharge ports 3 and 4 in this Example structure is about 2: 1, the ratio of the inflow amount of the coolant C to both the discharge ports 3 and 4 is the small discharge port 4 side. The amount of inflow is larger than the opening area ratio.
[0019]
In the above-described embodiment, the non-bulged portion 8 extending in the circumferential direction from the large discharge port 3 is not provided. However, in the present invention, the large discharge amount is within a range in which the coolant inflow amount to the small discharge port 4 can be sufficiently secured. The non-bulged portion 8 that continues in the circumferential direction from the outlet 3 may be provided with a certain circumferential width. That is, the deep hole cutting device of the present invention passes through the flow gap between the outer peripheral surface of the boring head and the inner peripheral surface of the cutting hole through two discharge ports at the top of the boring head provided at the tip of the hollow boring bar. In the configuration in which the coolant supplied to the cutting edge is introduced together with the chips and discharged to the outside through the boring bar, the discharge of the chips from the small discharge port is promoted and the clogging of the chips at the small discharge port In order to prevent this, the ratio of the coolant inflow amount to both discharge ports is the same as the opening area ratio of both discharge ports, or the ratio of the inflow amount to the small discharge ports is larger than the opening area ratio. The distribution gap is set. However, if the coolant flow rate to the small discharge port exceeds the flow rate to the large discharge port, the chip discharge performance at the large discharge port side will deteriorate and the overall cutting efficiency will be reduced. It is desirable to set the coolant inflow to the outlet to be equal to or less than the coolant inflow to the large outlet.
[0020]
Therefore, when the opening area ratio between the large and small discharge ports 3 and 4 is 2: 1 as in the above embodiment, the ratio of the coolant inflow amount to both the discharge ports 3 and 4 is 2: 1 to 1: 1. It is preferable to set the flow gap so as to be in a range. The means for setting the flow gap is not particularly limited, but the outer peripheral surfaces 21a and 21b on both sides separated by the two discharge ports 3 and 4 at the top 21 of the boring head 2 as in the above embodiment. A bulging portion 7 that narrows the flow gap T is formed in the upper and lower portions, and the ratio of the coolant inflow amount is different from the specified range depending on the presence / absence of the non-bulging portion 8 that continues in the circumferential direction from each of the discharge ports 3 and 4. It is easiest to adjust so that That is, this type of boring head grinds a raw material of a simple shape such as a round shaft shape and finishes it to a required shape, but in order to form the bulging portion 7, the setting shape by conventional grinding is slightly changed, In other words, it is only necessary to widen the width of the conventional bulging portion provided on the head rotation rear side of each mounting position of the guide pad and the peripheral cutting edge, and the amount of grinding can be reduced by the widening. .
[0021]
In the boring head 2 used in the above embodiment, the entire outer peripheral surface 21b side of the top portion 21 is the bulging portion 7, but in order to increase the supply of the coolant C to the top surface 2a, the outer peripheral surface 21b side is Similarly to the conventional configuration, the non-bulged portion 8 may be provided between the peripheral cutting edge 5b and the guide pad 6b mounting position. However, each of the guide pads 6a and 6b and the peripheral cutting edge 5b bulges to a certain circumferential width to receive the load applied to these members 6a, 6b and 5b during the cutting process. It is desirable to provide the portion 7. In the above embodiment, the bulging portion 7 is formed in the region of the top portion 21 of the bowling head 2. However, the bulging portion 7 may be formed from the top portion 21 to the intermediate portion 23.
[0022]
The deep hole cutting apparatus targeted by the present invention may have 2 or 4 or more cutting blades attached to the boring head, and the opening area ratio of the two large and small discharge ports according to these arrangement configurations and The thing with various opening shapes is included. In the above embodiment, an example of an external supply system in which the coolant C is supplied from the outside to the cutting edge side through the gap between the boring bar 1 and the cutting hole H is illustrated. The present invention can also be applied to an internal supply type deep hole cutting device that supplies coolant C between pipes.
[0023]
In this internal supply type deep hole cutting apparatus, a lead-out port that penetrates the inside and outside is provided in the middle part of the boring head, and a boring bar is provided in an annular step portion located on the cutting edge side of the lead-out port in the hollow part. The tip of the inner pipe is in liquid-tight contact, and the coolant supplied through the boring bar between the inner and outer pipes is led out between the outer peripheral surface of the boring head and the cutting hole through the outlet, and the coolant is cut in the same manner as described above. The waste flows into the two large and small discharge ports of the boring head and is discharged to the outside through the inner pipe of the boring bar. In this case as well, the ratio of the coolant inflow amount to both discharge ports is within the specified range. What is necessary is just to set a distribution gap to. In this internal supply method, in order to prevent the coolant from flowing back to the opening end side of the cutting hole, it is desirable to provide a backflow prevention means such as a labyrinth seal on the outer periphery of the base of the boring head or the outer periphery of the tip of the boring bar. .
[0024]
【The invention's effect】
According to the first aspect of the present invention, the cutting blade is passed through the flow gap between the outer peripheral surface of the boring head and the inner peripheral surface of the cutting hole into the two large and small discharge ports at the top of the boring head provided at the tip of the hollow boring bar. As a deep hole cutting device that flows the coolant supplied to the side with chips and discharges it to the outside through the boring bar, the ratio of the coolant inflow amount to both the discharge ports is the same as the opening area ratio of both discharge ports, Alternatively, since the flow gap is set so that the amount of inflow into the small discharge port is larger than the opening area ratio, the discharge of chips from the small discharge port is promoted, and the small discharge port is Chips are prevented from being clogged at the discharge port, and are excellent in chip dischargeability as a whole, have high cutting efficiency, and can reliably prevent the inability to cut due to the clogging and have high reliability.
Then, when setting the flow gap, bulges that narrow the flow gap on the outer peripheral surfaces of both sides separated by the two discharge ports at the top of the boring head than the outer peripheral portion along the lower edge of the openings of both discharge ports. Since the flow gap is set by the presence or absence or size of the non-bulged portion that continues in the circumferential direction from each of the two discharge ports, thereby setting the ratio of the coolant inflow amount, the outer peripheral portion of the boring head There is an advantage that the ratio of the inflow can be easily set by slightly changing the shape from the conventional shape.
[0025]
According to the invention of claim 2, in the deep hole cutting apparatus, the flow gap is set so that the coolant inflow amount to the small discharge port is equal to or less than the coolant inflow amount to the large discharge port. There is an advantage that a good cutting efficiency is ensured as a whole and a high cutting efficiency can be obtained without impairing the chip discharging performance on the outlet side.
[0027]
According to the third aspect of the present invention, in the deep hole cutting apparatus having the configuration in which the bulging portions are provided on the outer peripheral surfaces on both sides of the top portion of the boring head as described above, the deep hole cutting device has a non-bulging portion extending in the circumferential direction from the large discharge port. In addition, since it has a non-bulged part that extends from the small discharge port to the guide pad mounting position on the rear side in the head rotation direction, the coolant inflow area on the large discharge port side is narrowed and the proportion of coolant inflow to the small discharge port side As a result, the discharge of chips can be promoted, and the cross-sectional area of the coolant flow path can be greatly reduced at the top, increasing the coolant inflow pressure to both outlets, increasing the overall chip discharge efficiency. There is an advantage that the cutting efficiency can be further improved.
[0028]
According to the invention of claim 4 , in particular, the central cutting edge and the peripheral cutting edge are attached to the large discharge port side, and the intermediate cutting blade is attached to the small discharge port side, so that the opening area ratio of both discharge ports is substantially reduced. Since the ratio of the coolant inflow rate of the large discharge port / small discharge port is set to 2/1 to 1/1 as the deep hole cutting device of 2: 1, the amount of chips from the small discharge port is Discharge is good, no clogging of chips at the small discharge port, high cutting efficiency and excellent reliability are provided.
[Brief description of the drawings]
1A and 1B show a boring head used in a deep hole cutting apparatus according to an embodiment of the present invention, where FIG. 1A is a plan view of a top surface side and FIG. 1B is a side view of the boring head viewed from a large discharge port side.
FIG. 2 is a longitudinal side view showing a cutting state by the deep hole cutting apparatus.
FIG. 3 is a cross-sectional view at the top end position of the boring head in the same cutting process.
FIGS. 4A and 4B show a configuration example of a boring head used in a conventional deep hole cutting device, in which FIG. 4A is a plan view on the top surface side, and FIG. 4B is a side view as viewed from the large discharge port side.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hollow boring bar 1a Inside 2 Boring head 2a Top surface 2b Outer peripheral surface 20 Hollow part 21 Top part 21a, 21b Outer peripheral surface 22 Base 23 Middle part 3 Large discharge port 3a, 3b Opening side edge 3c Opening lower edge 4 Small discharge port 4a -4c Opening edge 4d Opening lower edge 5a Center part cutting edge 5b Peripheral part cutting edge 5a Intermediate part cutting edge 6a, 6b Guide pad 7 Expansion part 8 Non-expansion part C Coolant H Cutting hole S Chip T Flow gap

Claims (4)

At the top of the boring head provided at the tip of the hollow boring bar, there are two large and small discharge ports that open from the top surface to the outer peripheral surface and communicate with the inside of the boring bar, and the opening side of each discharge port facing the top surface of the boring head A cutting blade attached to the edge, and coolant that is supplied to the cutting blade through a flow gap between the outer peripheral surface of the boring head and the inner peripheral surface of the cutting hole together with chips generated by cutting. In the deep hole cutting device that flows into the outlet and discharges to the outside through the boring bar,
The flow gap is set so that the ratio of the coolant inflow amount to the two discharge ports is the same as the opening area ratio of the two discharge ports, or the ratio of the inflow amount to the small discharge port is larger than the opening area ratio. Ri name and,
In setting the flow gap, a bulging portion that narrows the flow gap on the outer peripheral surfaces of both sides separated by the two discharge ports at the top of the boring head than the outer peripheral portion along the lower opening edge of both discharge ports. A deep hole cutting device in which the flow gap is set by the presence or absence or size of a non-bulged portion that is formed and continues in the circumferential direction from each of the two discharge ports, thereby setting the ratio of the coolant inflow amount .   The deep hole cutting device according to claim 1, wherein the flow gap is set so that a coolant inflow amount to the small discharge port is equal to or less than a coolant inflow amount to the large discharge port. Without a non-bulging portion continuous in the circumferential direction from the large discharge opening, comprising a non-bulging portion continuous from the small outlet to guide pad mounting position of the head rotation direction rear side Claim 1 deep hole cutting according apparatus. A central cutting edge and a peripheral cutting edge are attached to the large outlet side, an intermediate cutting edge is attached to the small outlet side, and the opening area ratio of both outlets is approximately 2: 1. The deep hole cutting device according to any one of claims 1 to 3 , wherein a ratio of a coolant inflow amount of a large discharge port / a small discharge port is set to 2/1 to 1/1.

Images