Gear processing equipment

Abstract

To provide a gear machining device that can efficiently remove chips from a workpiece during skiving, even when the inner peripheral surface of the workpiece, which is an internal gear, has a complex shape, thereby improving the machining accuracy of the workpiece and extending the life of the tool. [Solution] A gear machining device (100) is a gear machining device that cuts a workpiece (102) by skiving to create an internal gear, and is equipped with multiple cleaning nozzles (120) that spray fluid. The workpiece has a groove (108) on the inside, and the cleaning nozzles have a counter-nozzle (120a) that sprays fluid toward the groove in the workpiece, at an angle upstream of the workpiece's rotation direction α, and discharge nozzles (120b, 120c) that spray fluid toward the exit side where a skiving cutter (110) that cuts the workpiece exits, thereby discharging chips (118) scattered by the spray from the counter-nozzle to the exit side.

Description

[Technical Field]

[0001] The present invention relates to a gear machining device that cuts a workpiece by skiving to create an internal gear, and that is capable of removing chips. [Background technology]

[0002] Skiving is a well-known machining method for creating gears. Skiving is performed by synchronizing the rotation of the workpiece and the rotation of the tool, with the tool's rotation axis tilted relative to the workpiece's rotation axis. This creates a difference in the rotation direction of the workpiece and the tool, causing "slip" when the tool interferes with the workpiece. This slip is used to remove the interfering parts from the workpiece, and to machine tooth grooves and other features into the workpiece.

[0003] During skiving, chips are generated when a workpiece is cut with a skiving cutter. If these chips adhere to the skiving cutter or the surface of the workpiece, the skiving cutter will get caught in the chips when the skiving cutter is brought into contact with the workpiece again to cut it, resulting in problems such as reduced machining accuracy.

[0004] In particular, in the case of internal gears, centrifugal force can cause chips to be pressed against the inner peripheral surface of the workpiece (i.e., the machined surface), which can cause them to remain instead of scattering. Therefore, for example, Patent Document 1 discloses a tooth groove machining device that can remove chips generated during machining.

[0005] In the tooth groove machining device disclosed in Patent Document 1, the control device sets the rotational speed of the workpiece W slower than the reference rotational speed during the return feed operation, and also sets the feed speed for returning the tool T to the fourth position P4 slower than the reference feed speed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-13963 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, centrifugal force is reduced by slowing down the rotational speed of the workpiece (machined object). This makes it easier for chips that have been pressed against the inner peripheral surface of the workpiece by centrifugal force to separate from the inner peripheral surface of the workpiece. However, the device in Patent Document 1 is configured to remove chips after one pass of machining is completed. However, when the inventors checked for chip bites, they found that chips that fly up during machining can get into the tooth groove that is about to be machined, causing bites at the machining position.

[0008] In particular, when the shape of the inner peripheral surface of the workpiece is complex, for example, when a groove is formed in advance on the inner peripheral surface of the workpiece, or when machining the inner peripheral surface of a blind hole, if the open end of the workpiece is blocked by the chuck of the workpiece shaft, creating a blind hole, scattered chips tend to become trapped and are more likely to get into the machining position. For this reason, the technology of Patent Document 1 was unable to efficiently remove chips depending on the shape of the inner peripheral surface of the workpiece, and there was room for further improvement.

[0009] The present invention aims to provide a gear machining device that can efficiently remove chips from a workpiece during skiving, even when the inner surface of the workpiece, which is an internal gear, has a complex shape, thereby improving the machining accuracy of the workpiece and extending the life of the tool. [Means for solving the problem]

[0010] To solve the above problems, a typical configuration of a gear cutting device according to the present invention is a gear cutting device that cuts a workpiece by skiving to create an internal gear, and is equipped with multiple cleaning nozzles that spray a fluid, the workpiece having a step on its inside, and the cleaning nozzles have counter-nozzles that spray the fluid toward the step in the workpiece, inclined upstream in the direction of rotation of the workpiece, and discharge nozzles that spray the fluid toward the exit side where the skiving cutter that cuts the workpiece exits, thereby discharging chips scattered by the spray from the counter-nozzles toward the exit side. Note that the "fluid" includes liquid coolant as well as air such as nitrogen gas and air.

[0011] In the above configuration, during skiving, multiple cleaning nozzles spray fluid while a skiving cutter cuts a workpiece having an internal step. The cleaning nozzle has a counter nozzle and a discharge nozzle. The counter nozzle sprays fluid toward the internal step of the workpiece at an angle upstream of the workpiece's rotation direction, thereby creating a fluid flow opposite to the workpiece's rotation direction. The fluid flow opposite to the workpiece's rotation direction is a flow opposite to the flow of chips generated when the workpiece is cut by the skiving cutter. Therefore, the chips can be scattered by the spray from the counter nozzle.

[0012] The discharge nozzle also sprays fluid toward the exit side of the skiving cutter. Therefore, when the skiving cutter reaches the bottom end of its stroke, for example, the discharge nozzle can discharge the chips scattered by the jet from the counter nozzle toward the exit side. Therefore, with the above configuration, even if the inner peripheral surface of the workpiece, which is an internal gear, has a complex shape during skiving, chips from the workpiece can be efficiently removed, improving the machining accuracy of the workpiece and extending the life of the tool.

[0013] The collision position where the fluid ejected from the counter nozzle collides with the workpiece is preferably set on the inner peripheral side surface of the step.

[0014] If the counter nozzle were to spray fluid toward the lower end face of the workpiece step, the chips would be pressed against the upper tooth surface (upper gear) of the workpiece, hindering discharge, which could result in chip jamming or accumulation. Therefore, the counter nozzle with the above configuration sprays fluid toward the inner peripheral side surface of the workpiece step (for example, the corner of the groove). This allows the counter nozzle to collide the chips with the workpiece step at an angle, ensuring reliable chip scattering.

[0015] The discharge nozzle is preferably set to inject the fluid in a direction along the tooth trace of the internal gear of the workpiece, just before the machining position.

[0016] This allows the discharge nozzle to move the chips scattered by the spray from the counter nozzle along the tooth trace of the workpiece's internal gear before they reach the machining position, and then to reliably discharge them to the escape side. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a gear machining device that can efficiently remove chips from a workpiece during skiving, even when the shape of the inner surface of the workpiece, which is an internal gear, is complex, thereby improving the machining accuracy of the workpiece and extending the life of the tool. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram showing a configuration of a gear machining device according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a diagram showing how chips from a workpiece are removed by the gear cutting device of FIG. 1. [Figure 3] 2A to 2C are diagrams illustrating the behavior of a fluid jetted from the counter nozzle of FIG. 1. [Figure 4] 4 is a diagram illustrating the behavior of a fluid ejected from the counter nozzle in FIG. 1 toward a position different from that in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0020] Figure 1 is a diagram showing the configuration of a gear machining apparatus 100 according to an embodiment of the present invention. The gear machining apparatus 100 is a machine tool that cuts a workpiece 102 by skiving to create a gear, and is also referred to as a skiving apparatus. The workpiece 102 is an internal gear having a large-diameter tooth flank 104, a small-diameter tooth flank 106, and a groove 108 (see Figure 2(b)) formed as a step between the tooth flanks 104 and 106.

[0021] The gear machining device 100 is equipped with a skiving cutter 110, and performs skiving on a workpiece 102 by rotating the skiving cutter 110. Note that Fig. 1 illustrates a state in which a large diameter tooth surface 104 of a workpiece 120 is being cut. The skiving cutter 110 is attached to a tool shaft 114 via a holder 112.

[0022] The gear machining device 100 also includes a control unit 116. The control unit 116 synchronously rotates the skiving cutter 110 and the workpiece 102 when performing cutting. The workpiece 102 rotates around a workpiece axis (not shown) at a predetermined rotation speed in a workpiece rotation direction α. ​​The skiving cutter 110 also rotates around a tool axis 114 at a predetermined rotation speed in a cutter rotation direction β.

[0023] The workpiece 102 is skived to produce an internal gear by feeding the skiving cutter 110 from the top to the bottom as shown in Fig. 1 while maintaining the crossing angle, which is the angle between the workpiece axis and the tool axis 114. Normally, the desired depth cannot be achieved in one cut, so multiple cutting processes (passes) are performed. The skiving cutter 110 is fed downward as shown in Fig. 1 and moves toward the side closer to the workpiece axis (the release side), until it releases from the large-diameter tooth flank 104 of the workpiece 102 and reaches the bottom end of its stroke.

[0024] In the gear machining apparatus 100, the workpiece 102 is machined at a machining position 117 by the skiving cutter 110, generating a large number of chips 118 (see FIG. 2(b)). Therefore, the gear machining apparatus 100 is provided with a plurality of (three in this example) cleaning nozzles 120 that spray a fluid such as air or coolant to efficiently remove the chips 118 from the workpiece 102. The plurality of cleaning nozzles 120 includes a counter nozzle 120a and discharge nozzles 120b and 120c. The plurality of cleaning nozzles 120 are attached to the tool shaft 114 and stroke together with the skiving cutter 110.

[0025] The counter-nozzle 120a is inclined upstream in the workpiece rotation direction α as indicated by arrow A, and sprays fluid from the spray port 122a toward the groove 108 in the workpiece 102. As a result, the counter-nozzle 120a creates a fluid flow in the opposite direction to the workpiece rotation direction α. ​​Note that the fluid flow in the opposite direction to the workpiece rotation direction α is a flow opposite to the flow of chips 118 (see FIG. 2(b)) generated when the workpiece 102 is cut.

[0026] The discharge nozzles 120b and 120c also inject fluid from the injection ports 122b and 122c, respectively, toward the exit side of the skiving cutter 110 as indicated by arrows B and C.

[0027] Figure 2 shows how chips 118 are removed from the workpiece 102 by the gear cutting apparatus 100 of Figure 1. Figure 2(a) shows the main parts of the gear cutting apparatus 100 as seen from above. Figure 2(b) shows the main parts of the gear cutting apparatus 100 together with a cross section of the workpiece 102.

[0028] First, a large number of chips 118 generated at the machining position 117 (see Figure 1) by the skiving cutter 110 are scattered along the workpiece rotation direction α, and are then trapped in the groove 108 of the workpiece 102 shown in Figure 2(b) by centrifugal force.

[0029] The counter-nozzle 120a sprays the fluid toward the inner peripheral side surface 124 of the groove 108 of the workpiece 102, as indicated by arrow A in Figure 2(b). In other words, the collision position where the fluid sprayed from the counter-nozzle 120a collides with the workpiece 102 is set to the inner peripheral side surface 124 of the groove 108. Furthermore, this collision position is set to a position far from the processing position 117.

[0030] As described above, the counter-nozzle 120a creates a fluid flow in the opposite direction to the flow of the chips 118, forming a swirling flow, for example, in the axial direction, as indicated by arrow D. The fluid then collides with the chips 118 at a speed that is the combination of the rotational speed of the workpiece 102 and the injection speed of the fluid. This allows the chips 118 to be scattered and removed.

[0031] Furthermore, the discharge nozzles 120b and 120c shown in Figure 2(b) are set to inject fluid from the injection ports 122b and 122c in the directions indicated by arrows B and C along the tooth trace of the internal gear of the workpiece 102 (here, the tooth trace of the large diameter tooth surface 104) just before the machining position 117 (see Figure 1).

[0032] As a result, the discharge nozzles 120b and 120c discharge the chips 118 scattered by the jet from the counter nozzle 120a to the exit side of the workpiece 102. In particular, when the skiving cutter 110 reaches the bottom end of its stroke, the jet from the counter nozzle 120a lifts the chips 118 from the groove 108 in the workpiece, and the jet from the discharge nozzles 120b and 120c can reliably discharge the chips 118 to the exit side.

[0033] Therefore, according to the gear machining device 100, even if the shape of the inner peripheral surface of the workpiece 102, which is an internal gear, is complex during skiving, chips from the workpiece 102 can be efficiently removed, thereby improving the machining accuracy of the workpiece 102 and extending the life of the tool.

[0034] Fig. 3 is a diagram illustrating the behavior of the fluid ejected from the counter-nozzle 120a in Fig. 1. The counter-nozzle 120a shown in Fig. 3(a) ejects the fluid toward the inner peripheral side surface 124 of the groove 108 in the workpiece 102 (see arrow A). Of course, the collision position of the fluid has a width (area), so the fluid also hits the corner 128 between the inner peripheral side surface 124 and the lower end face 126 of the groove, but in this embodiment, the "collision position" refers to the center of the collision range.

[0035] This allows the counter nozzle 120a to reliably scatter the chips 118 by moving them toward the upper end surface 130 of the groove 108 in the workpiece 102 (see arrow E) or along the lower end surface 126 of the groove 108 (see arrow F).

[0036] On the other hand, if the counter-nozzle 120a sprays fluid toward the lower end surface 126 of the groove 108 in the workpiece 102 as shown by arrow G in FIG. 3(b), the chips 118 will be pressed against the upper end surface 130 of the groove 108 (the lower end surface of the large-diameter tooth surface 104 (upper gear)) as shown by arrow H. This may hinder the discharge of the chips 118, leading to jamming or accumulation of the chips 118. Therefore, it is preferable that the counter-nozzle 120a sprays fluid toward the inner peripheral side surface 124 of the groove in the workpiece 102 as shown in FIG. 3(a).

[0037] Fig. 4 is a diagram illustrating the behavior of a fluid ejected from the counter-nozzle 120a in Fig. 1 toward a position different from that in Fig. 3. The counter-nozzle 120a shown in Fig. 4(a) ejects the fluid at an angle to the inner peripheral side surface 124 of the groove 108 in the workpiece 102 (see arrow J).

[0038] As a result, the counter-nozzle 120a can form a swirling flow that moves along the inner peripheral side surface 124 while colliding at an angle with the lower end surface 126 and the upper end surface 130 of the groove 108 of the workpiece 102, as indicated by arrow K. Therefore, the counter-nozzle 120a can prevent chips 118 from accumulating in the groove 108 of the workpiece 102.

[0039] On the other hand, if the counter-nozzle 120a sprays the fluid perpendicularly without any angle toward the lower end face 126 of the groove 108 in the workpiece 102, as shown by the arrow L in FIG. 4(b), the chips 118 will be pressed against a wide area toward the upper end face 130 of the groove 108, as shown by the arrow M. This may cause the chips 118 to become stuck or accumulate. Therefore, it is preferable that the counter-nozzle 120a sprays the fluid at an angle toward the inner peripheral side surface 124 of the groove 108 in the workpiece 102, as shown in FIG. 4(a).

[0040] Furthermore, in the gear machining device 100, during skiving, the counter nozzle 120a and the discharge nozzles 120b, 120c spray fluid while the skiving cutter 110 cuts the workpiece 102 having the groove 108 on the inside. This prevents the chips 118 from reaching the machining position during skiving, preventing the chips 118 from getting stuck.

[0041] Although the workpiece 102, which is an internal gear, has the groove 108 as a step, this is not limiting, and the open end of the workpiece 102 may be blocked to form a blind hole. Even in such a case, chips can be removed from the blind hole by injecting fluid from the counter nozzle 120a and the discharge nozzles 120b and 120c.

[0042] Furthermore, although the gear machining device 100 described above has two discharge nozzles 120b, 120c, this is not limited to this, and an appropriate number of one to three or more discharge nozzles may be arranged as long as it is possible to inject fluid toward the exit side where the skiving cutter 110 exits and discharge the chips to the exit side.

[0043] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0044] The present invention can be used as a gear machining device that cuts a workpiece by skiving to create an internal gear. [Explanation of symbols]

[0045] 100... gear machining device, 102... workpiece, 104, 106... tooth surface, 108... groove of workpiece, 110... skiving cutter, 112... holder, 114... tool axis, 116... control unit, 117... machining position, 118... chips, 120... cleaning nozzle, 120a... counter nozzle, 120b, 120c... discharge nozzle, 122a, 122b, 122c... injection port, 124... inner peripheral side surface of groove, 126... lower end surface of groove, 128... corner of groove, 130... upper end surface of groove

Claims

1. In a gear processing device that cuts a workpiece by skiving to create an internal gear, a plurality of cleaning nozzles for spraying fluid; The workpiece has a step on the inside, The cleaning nozzle is a counter nozzle that injects the fluid toward a step of the workpiece at an angle with respect to the workpiece axis so that the injection port faces upstream in the rotation direction of the workpiece; a discharge nozzle that discharges chips scattered by the jet from the counter nozzle toward the exit side by injecting the fluid toward the exit side of the skiving cutter that cuts the workpiece.

2. 2. The gear machining device according to claim 1, wherein a collision position where the fluid injected from the counter nozzle collides with the workpiece is set on an inner peripheral side surface of the step.

3. 3. The gear machining device according to claim 1, wherein the discharge nozzle is set to inject fluid in a direction along the tooth trace of the internal gear of the workpiece, before the machining position.

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