Gear machining device

Abstract

The present application provides a gear machining device capable of efficiently removing workpiece chips. In a gear machining device (shaving machining device 100, 100A) that forms a gear through shaving machining or gear shaving machining, a plurality of nozzles 140 that spray air or cutting fluid in front of a machining position 112 where a tool (shaving cutter 110) contacts a workpiece 120, 160 are provided. A collision position 142 where the air or cutting fluid sprayed from the plurality of nozzles collides with the workpiece is shifted toward a downstream side of a spraying direction 144 of the nozzle from an upstream side of a rotation direction 120a, 160a of the workpiece as the machining position is closer.

Description

Technical Field

[0001] This invention relates to a gear processing apparatus for forming gears by scraping or shaving, and more specifically to a gear processing apparatus capable of removing chips. Background Technology

[0002] Gear shaving and gear cutting are well-known machining methods for forming gears. Gear shaving is a machining process in which the workpiece rotates synchronously with the tool rotation, while the tool's rotation axis is tilted relative to the workpiece's rotation axis. This creates a difference between the workpiece's rotation direction and the tool's rotation direction, resulting in "slippage" when the tool interferes with the workpiece. This slippage is used to remove the interfering portion of the workpiece, thereby machining tooth grooves and the like on the workpiece.

[0003] Gear shaving, as an example, involves using a shaving cutter, which acts as a cutting tool, to press against a rotating workpiece while reciprocating, thereby machining teeth and other shapes onto the workpiece.

[0004] In tooth scraping, chips are generated when a tooth scraper cuts a workpiece. If these chips adhere to the surface of the tooth scraper or the workpiece, the tooth scraper will get stuck with the chips when it comes into contact with the workpiece again for cutting, resulting in reduced machining accuracy and other defects. The same problem occurs in tooth shaving.

[0005] Especially in the case of internal gears, there is a possibility that chips may be pressed against the inner circumferential surface of the workpiece (i.e., the machined surface) due to centrifugal force, and remain instead of scattering. Therefore, for example, Patent Document 1 discloses a gear grooving apparatus capable of removing chips generated during machining. In the gear grooving apparatus disclosed in Patent Document 1, the control device, during the return feed operation, makes the rotational speed of the workpiece W lower than the reference rotational speed, and makes the feed speed for returning the tool T to the fourth position P4 lower than the reference feed speed.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2021-13963 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In Patent Document 1, centrifugal force is reduced by slowing down the rotational speed of the workpiece. This makes it easier for chips pressed against the inner circumferential surface of the workpiece by centrifugal force to detach. However, the device in Patent Document 1 removes chips only after one pass of machining. However, the inventors investigated chip jamming and found that chips thrown up during machining can enter the tooth groove to be machined, causing jamming at the machining location.

[0011] Especially when the inner circumferential surface of the workpiece has a complex shape, such as when grooves are pre-formed on the inner circumferential surface of the workpiece, when the inner circumferential surface of a blind hole is being machined, or when the chuck of the workpiece shaft blocks the open end of the workpiece, creating a blind hole, the raised chips are more likely to be trapped and enter the machining position. Therefore, depending on the shape of the inner circumferential surface of the workpiece, the technology in Patent Document 1 cannot efficiently remove chips and there is room for further improvement.

[0012] Furthermore, even in external gears, when the cutting fluid is liquid, there is a situation where chips adhere to the tooth grooves.

[0013] In view of the above-mentioned problems, the present invention aims to provide a gear processing apparatus that can efficiently remove chips from a workpiece during scraping or shaving, even when the inner circumferential surface of the workpiece is complex as an internal gear or as an external gear, thereby improving the workpiece processing accuracy and extending the tool life.

[0014] Solution for solving the problem

[0015] To solve the above problems, the representative structure of the gear processing device involved in the present invention is as follows: a gear processing device for forming gears by scraping or shaving, which has multiple nozzles. The multiple nozzles spray air or cutting fluid at the front side of the processing position where the tool contacts the workpiece. The collision position where the air or cutting fluid sprayed from the multiple nozzles collides with the workpiece is closer to the processing position from the upstream side of the workpiece's rotation direction and shifts towards the downstream side of the nozzle's spray direction.

[0016] Based on the above structure, by using air or cutting fluid ejected from the nozzle, chips can be efficiently and reliably removed in front of the machining position, thereby preventing chips from getting stuck at the machining position. This results in improved workpiece machining accuracy and extended tool life.

[0017] Of the plurality of nozzles, the nozzle closest to the cutting tool preferably sprays in the direction along the tooth line. According to this configuration, chips within the tooth grooves can be removed along the tooth line, thereby keeping the tooth groove portion corresponding to the machining position clean.

[0018] The plurality of nozzles are preferably each connected to an independent supply source of air or cutting fluid. According to this configuration, high pressure from each supply source can be supplied to the nozzles, thereby improving chip removal capability.

[0019] The workpiece is preferably an internal gear. According to this structure, although chips tend to accumulate in the tooth grooves due to centrifugal force (making them difficult to remove) in the case of an internal gear, the chips accumulated in the tooth grooves can be forcibly removed by sequentially spraying air or cutting fluid at an offset.

[0020] The effects of the invention

[0021] According to the present invention, even when the inner circumferential surface of the workpiece has a complex shape or when it is used as an external gear, the chips of the workpiece can be removed efficiently, thereby providing a gear machining apparatus that can improve the machining accuracy of the workpiece and extend the tool life. Attached Figure Description

[0022] Figure 1 This is a diagram illustrating the gear processing apparatus according to an embodiment of the present invention;

[0023] Figure 2 This diagram illustrates the concept of chips remaining on the machining surface being removed sequentially.

[0024] Figure 3 This diagram illustrates the relationship between the collision position and the machining position when the workpiece is an external gear.

[0025] Explanation of reference numerals in the attached figures

[0026] 100, 100A, Gear scraping device; 102, Tool holder; 103, Tool shaft; 110, Gear scraper; 110a, Tool rotation direction; 112, Machining position; 114, 114a, 114b, 114c, Chips; 120, 160, Workpiece; 120a, 160a, Workpiece rotation direction; 122, Large diameter tooth surface; 124, Small diameter tooth surface; 126, Groove; 130, Control unit; 140, 140a, 140b, 140c, Nozzle; 141, Air jet; 142, 142a, 142b, 142c, Collision position; 144, Jet direction; 150, Supply source. Detailed Implementation

[0027] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in these embodiments are merely examples to facilitate understanding of the invention and, unless otherwise specified, do not constitute a limitation on the invention. Furthermore, in this specification and the accompanying drawings, elements with substantially the same function or structure are omitted from repeated description by using the same reference numerals; additionally, elements not directly related to the present invention are omitted from the illustrations.

[0028] Figure 1 This is a diagram illustrating the gear processing apparatus according to an embodiment of the present invention. Figure 1 As shown, the gear processing device (hereinafter referred to as "gear scraping device 100") that forms gears by scraping is a machine tool that performs gear scraping on the workpiece 120 by rotating scraper 110. Figure 1 The workpiece 120 shown is an internal gear with a groove 126 between the large diameter tooth surface 122 and the small diameter tooth surface 124. The scraper 110 is mounted on the tool shaft 103 via the tool holder 102.

[0029] Figure 1 The illustration shows the cutting of the large-diameter tooth surface 122 of the workpiece 120. During the cutting process, the control unit 130 causes the scraper 110 to rotate synchronously with the workpiece 120. The workpiece 120 rotates at a predetermined speed along the workpiece rotation direction 120a with the workpiece axis (not shown) as the center, and the scraper 110 also rotates at a predetermined speed along the tool rotation direction 110a with the tool axis 103 as the center.

[0030] Furthermore, while maintaining the angle between the workpiece axis and the tool axis 103, i.e., the axial angle, the scraper 110 is moved from... Figure 1 The feed is directed downwards from the top, thereby performing a scraping process on the workpiece 120 to manufacture an internal gear. Typically, since the required depth cannot be achieved in a single cut, multiple cutting operations (feed passes) are required.

[0031] Especially Figure 1 In this process, the tooth-scraping apparatus 100 includes multiple nozzles 140 for spraying air or cutting fluid. In the following description, when it is necessary to distinguish between the multiple nozzles, reference numerals 140a to 140c will be used; otherwise, only reference numeral 140 will be used. Furthermore, in... Figure 1 The example used is three nozzles 140a~140c, but it can also be two or more.

[0032] Multiple nozzles 140 are each connected to an independent air or cutting fluid supply source 150. High pressure from each supply source 150 can be supplied to the nozzles 140, thereby increasing the chip volume 114 (see reference). Figure 2 Its removal capability. Additionally... Figure 1 The supply source 150 shown is preferably air (dry machining). Since the air pressure is preferably relatively high, a booster valve + air tank or a booster compressor + air tank can be suitably used. Furthermore, in this invention, cutting fluid (cutting oil) can be used instead of booster air. In the following embodiments, the case of air injection will be described.

[0033] Figure 2 This diagram illustrates the concept of sequentially removing chips 114 retained on the machined surface. First, the workpiece 120 is machined by the scraper 110 at machining position 112, generating a large amount of chips (not shown). It is assumed that the scattered chips are retained in the tooth grooves due to centrifugal force. In... Figure 2 In the illustration, for a single chip 114, reference numerals 114a to 114c are used to indicate its three moving positions. Furthermore, in the following description, reference numerals 142a to 142c are used when it is necessary to distinguish the collision positions; otherwise, only reference numeral 142 is used.

[0034] exist Figure 2 In the figure, the nozzle 140a on the left (upstream of the workpiece 120 in the direction of rotation) sprays air (not shown) along the spray direction 144 of the tooth line. The area near the center of the range where the sprayed air collides with the tooth surface 122 is called the collision position 142a, which is shown as a dashed line in the figure. The nozzle 140a on the left continuously cools the tooth line along its spray direction 144 with air while pushing the chips 114a entering the airflow. The chips 114a on the left that collide with the air are directed along the spray direction 144, i.e. towards... Figure 2 Move downwards.

[0035] exist Figure 2 In the figure, the central nozzle 140b is offset downstream of the left nozzle 140a in the jet direction 144 (lower part of the figure). Therefore, the collision position 142b is also offset downstream of the collision position 142a in the jet direction 144. When the central chip 114b reaches the position of the central nozzle 140b, the central chip 114b, which collides with the air, is blown along the jet direction 144 and moves further downward in the figure.

[0036] exist Figure 2In the diagram, the right nozzle 140c is further offset downstream of the central nozzle 140b in the jet direction 144. Therefore, the collision position 142c is also further offset downstream of the collision position 142b in the jet direction 144. When the right-side chip 114c reaches the position of the right-side nozzle 140c, the right-side chip 114c, colliding with the air, is blown along the jet direction 144 and moves further downwards. The right-side chip 114c is removed from the workpiece 120 without reaching the machining position 112.

[0037] As described above, the collision positions 142a to 142c, where the air ejected from the multiple nozzles 140 collides with the tooth surface 122, shift from the upstream side of the workpiece 120's rotation direction 120a closer to the machining position 112, towards the downstream side of the nozzles 140's ejection direction 144. According to this structure, even if the chip 114 is forcefully pressed against the tooth surface due to centrifugal force, it is removed sequentially by the multiple nozzles 140, thus enabling efficient and reliable removal of the chip 114 in front of the machining position 112. This prevents the chip 114 from getting stuck at the machining position 112, improving the machining accuracy of the workpiece 120 and extending the tool life.

[0038] Furthermore, since the machining position 112 of the scraper 110 is inclined relative to the machining surface of the workpiece 120, the machining position 112 is illustrated as an elliptical dashed line. The machining position 112 is also referred to as the machining area. Multiple collision points 142a~142c are preferably located in... Figure 2 The vertical direction corresponds to the upper to lower side of the processing position 112. The collision position 142c at the downstream side (near the processing position) preferably corresponds to the area below the center of the processing position 112.

[0039] Furthermore, among the plurality of nozzles 140, the jet direction 144 of at least the nozzle 140c closest to the scraper 110, which serves as the cutting tool, is preferably along the tooth line direction. More preferably, the jet direction 144 of all nozzles 140a to 140c is along the tooth line direction. According to this structure, the chips 114 in the tooth groove can be removed along the tooth line direction, keeping the tooth groove portion corresponding to the machining position 112 clean.

[0040] In the above description, to offset the collision positions 142a-142c, the method of offsetting the height of nozzles 140a-140c (air outlet 141) was explained. However, the radial distance between nozzles 140a-140c and tooth surface 122 could also be gradually increased, or the radial angle (angle relative to the workpiece axis) of nozzles 140a-140c could be gradually changed. However, by using a structure that offsets the height, the driving force or removal capacity of the air at each collision position 142 can be maintained at a high level.

[0041] Furthermore, it is preferable that the height position of the collision position 142 of all nozzles 140 is linked to the vertical movement or position of the scraper 110. All nozzles 140 may, for example, be fixed to the cutter shaft 103.

[0042] Figure 3 The diagram shown illustrates the relationship between the collision positions 142a-142c and the machining position 112 when the workpiece 160 is an external gear. Even in the case of an external gear, the collision position 142, where the air ejected from the multiple nozzles 140a-140c collides with the machining surface of the workpiece 160, shifts from the upstream side of the workpiece 160's rotation direction 160a towards the machining position 112, and further downstream of the nozzles 140a-140c's ejection direction 144.

[0043] According to this structure, even in the case of external gears, residual chips in the tooth grooves can be efficiently and reliably removed in front of the machining position 112 by air ejected from the nozzle 140. This prevents chips from getting stuck at the machining position 112, thereby improving the machining accuracy of the workpiece 160 and extending the tool life.

[0044] As mentioned above Figures 1 to 3 As explained, the scraping processing apparatus 100 and 100A according to this embodiment can efficiently remove chips 114 to prevent jamming, and can improve the machining accuracy of workpieces 120 and 160 and extend the tool life. In addition, the machining method for forming gears is not limited to scraping processing; chips generated by shaving processing can also be efficiently removed with the same structure.

[0045] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it is obvious that the present invention is not limited to the above examples. Those skilled in the art will readily conceive of various modifications or alterations within the scope of the claims, and it is understood that these also fall within the technical scope of the present invention.

[0046] Industrial availability

[0047] This invention can be used as a gear processing apparatus for forming gears by scraping or shaving.

Claims

1. A gear processing apparatus, which forms gears by scraping or shaving, characterized in that, It is equipped with multiple nozzles that spray air or cutting fluid at the front side of the machining position where the tool contacts the workpiece. The collision position where the air or cutting fluid ejected from the plurality of nozzles collides with the workpiece is closer to the machining position from the upstream side of the workpiece's rotation direction and further downstream from the nozzle's spray direction.

2. The gear processing apparatus according to claim 1, characterized in that, Of the plurality of nozzles, at least the nozzle closest to the cutting tool has a spray direction along the tooth line direction.

3. The gear processing apparatus according to claim 1, characterized in that, The plurality of nozzles are each connected to an independent supply source of air or cutting fluid.

4. The gear processing apparatus according to claim 1, characterized in that, The workpiece is an internal gear.

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