Method and apparatus for manufacturing spline structures

Abstract

The present invention provides a method and apparatus for manufacturing spline structures that can improve the efficiency of the manufacturing process. [Solution] A manufacturing method for producing a spline structure having splines 22 by cutting the outer surface of a workpiece 21 with a hob cutter 11, comprising a cutting step S10 in which the workpiece 21 and the hob cutter 11 are rotated and the hob cutter 11 or the workpiece 21 is moved in the axial direction of the workpiece 21, and the outer surface of the workpiece 21 is cut with the hob cutter 11, comprising a conventional cutting step S11 in which the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 are the same at the contact point between the workpiece 21 and the hob cutter 11, and a climb cutting step S12 in which the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 are in opposite directions.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an external spline structure having a plurality of external teeth, and a manufacturing apparatus used in the manufacturing method.

Background Art

[0002] A spline structure has a plurality of external teeth and transmits power by combining with a mating member having corresponding internal teeth. Examples of such spline structures include a spline shaft, a spline joint, a spur gear, a pinion gear, a gear coupling, and the like. As disclosed in Patent Document 1, a manufacturing apparatus including a hob cutter is used to cut a workpiece with the hob cutter to form external teeth. In the cutting method using the above hob cutter, at the contact point between the workpiece and the hob cutter, there are two methods: a conventional cut in which the moving direction of the hob cutter with respect to the workpiece and the rotation direction of the hob cutter are in the same direction, and a climb cut in which the moving direction and the rotation direction are in opposite directions. A normal manufacturing apparatus can only execute either the conventional cut or the climb cut. In many cases, the climb cut is adopted in view of merits such as less wear of the hob cutter and long tool life.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above climb cut has a demerit that large burrs are likely to occur on the workpiece, and work for removing burrs is required after the cutting operation. On the other hand, conventional cutting is less prone to burrs compared to climbing cuts, but it is more likely to cause welding of cutting chips and shavings to the tooth surface and root of the external teeth, requiring the removal of such welded material after the cutting process. In other words, in the manufacture of spline structures, whether climb cut or conventional cut, it is necessary to remove burrs or welded material after the cutting work, and this post-cutting work hinders improvements in the efficiency of the manufacturing process.

[0005] This invention has been made in view of the above circumstances, and aims to provide a method for manufacturing spline structures and a manufacturing apparatus that can improve the work efficiency related to manufacturing. [Means for solving the problem]

[0006] To solve the above problems, the present invention is shown below. (1) The present invention provides a method for manufacturing a spline structure, which involves cutting the outer surface of a cylindrical or columnar workpiece with a hob cutter to produce a spline structure, The cutting process includes a procedure in which the workpiece and the hob cutter are rotated around their respective axes, the hob cutter is brought into contact with the outer circumferential surface of the workpiece, and the hob cutter or the workpiece is moved in the axial direction of the workpiece, thereby cutting the outer circumferential surface of the workpiece with the hob cutter to form the spline, The aforementioned cutting process is A conventional cutting process in which the cutting is performed such that the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter are in the same direction at the contact point between the workpiece and the hob cutter, The gist of the invention is to include a climb-cutting step in which the cutting is performed such that the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter are opposite at the point of contact between the workpiece and the hob cutter. (2) In the method for manufacturing a spline structure of the present invention, the cutting step is: After partially forming only the ends of the spline in the conventional cutting process, The entire spline can be formed by overlapping the end portion during the climb-cutting process. (3) The spline structure manufacturing apparatus of the present invention is a manufacturing apparatus for manufacturing a spline structure having splines by cutting the outer surface of a cylindrical or columnar workpiece with a hob cutter, A support shaft that rotatably supports the workpiece at its axial center, The hob cutter is rotatably supported around a cutter axis extending in a direction perpendicular to the support shaft, A rotating mechanism for rotating the hob cutter, A contact mechanism that brings the workpiece and the hob cutter into contact with each other, A moving mechanism for moving the hob cutter or the workpiece in the axial direction of the workpiece, The system comprises a control unit that controls the operation of the rotating mechanism, the contact mechanism, and the moving mechanism, The control unit, A conventional cutting means that performs the cutting by making the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter the same at the contact point between the workpiece and the hob cutter, The gist of the invention is to provide a climb-cutting means that performs the cutting by moving the hob cutter in opposite directions relative to the workpiece and rotating the hob cutter at the point of contact between the workpiece and the hob cutter. (4) In the spline structure manufacturing apparatus of the present invention, the control unit can execute the conventional cutting means and the climb cutting means in that order. [Effects of the Invention]

[0007] According to the present invention, when forming a spline by cutting the outer surface of a workpiece with a hob cutter, the generation of burrs and welds can be suppressed by using both conventional cuts and climb cuts, the post-cutting work related to the removal of burrs and welds can be simplified, and the work efficiency related to the manufacture of spline structures can be improved. [Brief explanation of the drawing]

[0008] The present invention will be further described in the following detailed description with reference to the drawings, which refer to several drawings, with the same reference numerals indicating the same parts in several of the drawings. [Figure 1] (a) and (b) are flowcharts showing the method for manufacturing the spline structure of the present invention. [Figure 2] An explanatory diagram showing cutting using conventional cutting techniques. [Figure 3] An explanatory diagram showing cutting using the climb cut method. [Figure 4] An explanatory diagram showing the process of spline formation through an example of a cutting process. [Figure 5] This is a perspective view showing a spline structure. [Figure 6] This is a perspective view showing the manufacturing apparatus for spline structures according to the present invention. [Figure 7] This is a flowchart illustrating an example of the flow of a cutting process using manufacturing equipment. [Modes for carrying out the invention]

[0009] The matters shown here are for illustrative purposes and to exemplarily explain embodiments of the present invention, and are described for the purpose of providing an explanation that is considered to be the most effective and easy-to-understand for the principles and conceptual features of the present invention. In this regard, it is not intended to show the structural details of the present invention more than necessary for a fundamental understanding of the present invention, and it is to clarify to those skilled in the art how some forms of the present invention are actually embodied by the description in combination with the drawings.

[0010] [1] Method for manufacturing a spline structure The method for manufacturing a spline structure in the present invention is a manufacturing method for manufacturing a spline structure having a plurality of external teeth by cutting the outer peripheral surface of a processing object having a cylindrical or columnar shape with a hob cutter, while rotating the processing object and the hob cutter around their respective axial centers, moving the hob cutter or the processing object in the axial direction of the processing object while bringing the hob cutter into contact with the outer peripheral surface of the processing object, and forming the external teeth by cutting the outer peripheral surface of the processing object with the hob cutter, and includes a cutting step. The cutting step includes a conventional cutting step of performing the cutting so that the moving direction of the processing object with respect to the hob cutter and the rotating direction of the hob cutter are in the same direction at the contact point between the processing object and the hob cutter, and a climb cutting step of performing the cutting so that the moving direction of the processing object with respect to the hob cutter and the rotating direction of the hob cutter are in opposite directions at the contact point between the processing object and the hob cutter, and is characterized by this.

[0011] The method for manufacturing a spline structure includes a cutting step S10 (see FIGS. 1(a) and (b)). The cutting step S10 is, for example, a step for manufacturing a spline structure 20 in which a spline 22 having a plurality of internal grooves 22A and external teeth 22B is formed on the outer peripheral surface as shown in FIG. In other words, the cutting process S10 is a process of manufacturing a spline structure from a workpiece 21, which is cylindrical or columnar in shape, by cutting the outer surface of the workpiece 21 with a hob cutter 11 and forming splines 22 on the outer surface. A hob cutter is a cutting tool having multiple cutting blades arranged in a screw-like (spiral) pattern. By bringing the hob cutter into contact with the workpiece while synchronizing their rotations, the cutting blades can cut the outer surface of the workpiece, thereby forming a spline. The pressure angle, number of teeth, tooth width, number of threads, and number of grooves of the hob cutter are appropriately selected according to the desired spline size and shape. Any hob cutter commonly used for spline formation can be used according to the present invention and is not particularly limited. Furthermore, although not specifically shown in the figures, the cutting process S10 begins with rotating the hob cutter and bringing it close to and into contact with the workpiece, thereby causing the cutting blade to bite into (engage) the outer surface of the workpiece. After this operation, the cutting process is performed to cut the outer surface of the workpiece with the cutting blade to form a spline, as shown in Figures 2 and 3.

[0012] Specifically, in the cutting process S10, as shown in Figures 2 and 3, the workpiece 21 is rotated around its axis Ax1, and the hob cutter 11 is rotated around its axis Ax2. In the above-described rotating state, the workpiece 21 and the hob cutter 11 are brought into contact with the outer circumferential surface of the workpiece 21, and further, either the hob cutter 11 or the workpiece 21 is moved relative to the other in the direction of the axis Ax1 of the workpiece 21. As a result, multiple internal grooves 22A are formed on the outer circumferential surface of the workpiece 21 cut by the hob cutter 11, and external teeth 22B are formed between each internal groove 22A, thereby forming a spline 22 consisting of these internal grooves 22A and external teeth 22B.

[0013] Furthermore, if either the hob cutter 11 or the workpiece 21 moves relative to the other in the direction of the axis Ax1 of the workpiece 21, the object of that movement can be either the hob cutter 11 or the workpiece 21. That is, the hob cutter 11 can move in the direction of axis Ax1 relative to the workpiece 21, or the workpiece 21 can move in the direction of axis Ax1 relative to the hob cutter 11. Normally, from the viewpoint of improving machining accuracy, the hob cutter 11 is designed to move in the direction of the axis Ax1 relative to the workpiece 21.

[0014] The cutting methods for the workpiece 21 using the hob cutter 11 described above include conventional cutting (hereinafter also referred to as "conve cut") and climb cutting. Conve-cut is a cutting method in which, as shown in Figure 2, at the contact point CP between the workpiece 21 and the hob cutter 11, the direction of movement of the hob cutter 11 relative to the workpiece 21 is the same as the direction of rotation of the hob cutter 11. More specifically, at the contact point CP between the workpiece 21 and the hob cutter 11, the rotation direction of the hob cutter 11 (indicated by the black arrow in the figure) is from top to bottom in the vertical direction shown in Figure 2. Conveyor cut is a cutting method in which, at the contact point CP, the movement direction of the hob cutter 11 (indicated by the white arrow in the figure) is from top to bottom in the vertical direction shown in Figure 2, so as to be in the same direction as the rotation direction.

[0015] Climb cut is a cutting method in which, as shown in Figure 3, at the contact point CP between the workpiece 21 and the hob cutter 11, the direction of movement of the hob cutter 11 relative to the workpiece 21 is in the opposite direction to the rotation direction of the hob cutter 11. More specifically, at the contact point CP between the workpiece 21 and the hob cutter 11, the rotation direction of the hob cutter 11 (indicated by the black arrow in the figure) is from top to bottom in the vertical direction shown in Figure 3. Climb cut is a cutting method in which, at the contact point CP, the movement direction of the hob cutter 11 (indicated by the white arrow in the figure) is from bottom to top in the vertical direction shown in Figure 3, so as to be opposite to the rotation direction.

[0016] In the manufacturing method of the present invention, the cutting step S10 comprises two steps, as shown in Figures 1(a) and (b): a conventional cutting step S11 (abbreviated as "conveyor cut" in each figure) in which the workpiece 21 is cut by the conveyor cut described above, and a climb cutting step S12 (abbreviated as "climb cut" in each figure) in which the workpiece 21 is cut by the climb cut described above. If the cutting process S10 comprises two processes, the conveyor cutting process S11 and the climb cutting process S12, then there are no particular limitations on the execution order of the conveyor cutting process S11 and the climb cutting process S12. The execution order of the conveyor cutting process S11 and the climb cutting process S12 can be as follows: as shown in Figure 1(a), the conveyor cutting process S11 is executed first, followed by the climb cutting process S12; or as shown in Figure 1(b), the climb cutting process S12 is executed first, followed by the conveyor cutting process S11.

[0017] Here, the conveyor cut is a cutting method in which multiple cutting blades of the hob cutter 11 overlap and cut a single cutting surface. In this conveyor cut, it is thought that burrs are less likely to form because multiple cutting blades overlap and cut the same cutting surface, for example, by being scraped off. However, in conveyor cutting, the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 are the same. In other words, the direction in which the hob cutter 11 moves and the cutting direction are the same. As a result, the direction in which cutting chips and other debris are released by scraping with the cutting blade is the direction in which the hob cutter 11 moves (in other words, the "forward direction"). Therefore, in conveyor cutting, it is easy for cutting chips and other debris to get stuck, and it is thought that this stuck-in debris makes it easier for welded material to adhere. In addition, in conveyor cutting, the number of times the cutting blade of the hob cutter 11 contacts the workpiece 21 increases, which is thought to shorten tool life.

[0018] Climb cut is a cutting method in which the cutting blade first cuts in the lateral (circumferential) direction, and the amount of material removed is gradually increased as the cutting progresses. In other words, it can be described as a cutting method in which the cutting surface formed by one cutting blade of the hob cutter 11 is connected to and extended by the cutting surfaces formed by other cutting blades. In climb cutting, the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 are opposite; that is, the direction in which the hob cutter 11 moves and the cutting direction are opposite. Therefore, the direction in which cutting chips and other debris are released by the scraping action of the cutting blade is opposite to the direction in which the hob cutter 11 moves (in other words, the "reverse direction"). For this reason, climb cutting is less likely to cause choking of cutting chips and other debris, and less likely to cause adhesion of welded material due to choking. In addition, the number of times the cutting blade of the hob cutter 11 contacts the workpiece 21 is reduced, which is thought to extend tool life.

[0019] However, in climb cutting, the cutting blade cuts in the lateral direction (circumferential direction), and such lateral cutting has high cutting resistance and is likely to cause plastic flow of the material, so it is thought that the cutting blade will plastically deform the outer surface of the workpiece 21 and burrs are likely to form. In particular, at the start of cutting, the cutting blade is strongly bitten into the outer surface of the workpiece 21 where no internal grooves or the like are formed, so the cutting resistance is high and burrs are likely to form. Furthermore, the sharp (or triangular) portion at the end of the inner groove 22A of the spline 22 is the portion machined by the cutting blade moving in an arc as it exits the workpiece 21 due to the rotation of the hob cutter 11; in other words, it is the portion machined by the relief of the hob cutter 11. The sharp portion at the end of the inner groove 22A machined by the relief of the hob cutter 11 is formed at the end of cutting in the case of a conveyor cut (see Figure 4), and at the start of cutting in the case of a climb cut. In the case of a climb cut, if a burr forms on the sharp end of the inner groove 22A, the hob cutter 11 moves away from that part, preventing the cutting blade from reaching the burr, and thus the burr remains unchamfered by the hob cutter 11.

[0020] As described above, while the conveyor cut has the advantage of being less prone to burr formation, it also has disadvantages such as being prone to welding material adhering to the cutting surface and shortening tool life. The climb cut has the advantage of being less prone to welding material adhering to the cutting surface and extending tool life, but it also has disadvantages such as being prone to burr formation. Considering the respective advantages and disadvantages of the conveyor cut and climb cut processes described above, it is preferable that the conveyor cut process S11 be executed first, followed by the climb cut process S12 (see Figure 1(a)). In other words, the disadvantage of climb cutting is the formation of burrs, especially at the start of cutting. However, by performing the initial cutting using a conveyor cut, which has the advantage of being less prone to burr formation, the disadvantage of climb cutting can be eliminated.

[0021] In the cutting process S10, when both a conveyor cut process and a climb cut process are performed to form the spline 22, an overlapping portion of the spline 22 can be provided between the portion formed by the conveyor cut and the portion formed by the climb cut. In particular, when the conveyor cutting process is performed first and the climb cutting process is performed later, it is preferable to provide an overlapping portion between the conveyor cutting and climb cutting processes. In other words, by creating an overlapping portion between the two cuts, the weld material that adheres to the cutting surface during the conveyor cut can be scraped off by the cutting blade of the hob cutter 11 passing over that cutting surface during the climb cut. Thus, the disadvantage of the conveyor cut, namely the adhesion of weld material to the cutting surface, can be eliminated.

[0022] In the cutting process S10, when both a conveyor cut process and a climb cut process are performed to form the spline 22, the size of the portion formed by the conveyor cut and the size of the portion formed by the climb cut can be made larger than the other, or both sizes can be made equal. In particular, when the conveyor cutting process is performed first and the climb cutting process is performed later, it is preferable to make the size of the portion formed by the climb cutting larger than the size of the portion formed by the conveyor cutting. In other words, by increasing the size of the formed area using climb cut, which has the advantage of extending tool life, the disadvantage of conveyor cut, which is its short tool life, can be overcome.

[0023] Therefore, when the cutting process S10 performs both a conveyor cut process and a climb cut process to form the spline 22, it is preferable to partially form only the end of the spline 22 in the conveyor cut process, and then to form the entire spline 22 by overlapping the end in the climb cut process. Figure 4 is an explanatory diagram showing the spline 22 formation process in a specific example of the cutting process S10, where only the end of the spline 22 is partially formed in the conveyor cut process, and then the entire spline 22 is formed by overlapping the aforementioned end in the climb cut process.

[0024] In other words, in the cutting process S10 described above, in order to perform the conveyor cut process, the start position of the conveyor cut and the end position of the conveyor cut are set on the outer surface of the workpiece 21 (see the upper diagram in Figure 4). The end position of the conveyor cut can be set to the base end of the spline 22, which is shown by the dashed line in the figure. At the base end of the spline 22, the sharp portion of the inner groove is machined by the relief of the hob cutter and is formed beyond the end position of the conveyor cut, as shown in the upper diagram in Figure 4. Furthermore, the starting position of the conveyor cut can be set according to the size of the overlapping portion between the conveyor cut and the climb cut.

[0025] In cutting process S10, when the conveyor cut process is executed, only the ends of the splines 22 are partially formed on the outer surface of the workpiece 21 (see the middle diagram in Figure 4). The length L1 of the ends of the splines 22 partially formed by this conveyor cut can be appropriately set according to the size of the overlapping portion between the conveyor cut and the climb cut. In cutting process S10, the climb cut process is performed after the conveyor cut process to form the entire spline 22 (see the lower diagram in Figure 4). At this time, as shown by the shading in Figure 4, the portion cut by the climb cut overlaps with the portion cut by the conveyor cut at the end of the spline 22 described above. In other words, when performing the climb cut process, the end of the spline 22 is already formed by the conveyor cut at the start of the climb cut, and therefore the formation of burrs, which is a disadvantage of climb cuts, can be eliminated.

[0026] The total length L2 of the spline 22 formed in the above cutting process S10 is not particularly limited, but is usually between 1 mm and 1000 mm. The total length L2 is preferably between 2 mm and 800 mm, more preferably between 3 mm and 600 mm, and even more preferably between 4 mm and 500 mm. The length L1 of the end of the spline 22 is not particularly limited, as long as it can suppress the adhesion of weld material and the formation of burrs. Specifically, from the viewpoint of effectively suppressing the adhesion of weld material and the formation of burrs, the length L1 of the end of the spline 22 is preferably 0.1 mm to 10 mm, more preferably 0.15 mm to 7.5 mm, even more preferably 0.2 mm to 5 mm, and particularly preferably 0.5 mm to 3.5 mm. The size of the overlapping portion between the two cuts will correspond to the length L1 of the end of the spline 22.

[0027] The spline structure 20 formed from the workpiece 21 by the manufacturing method of the present invention is not particularly limited and can include spline shafts, spline couplings, spur gears, pinion gears, gear couplings, and the like. The spline structure 20 has a configuration such as that shown in Figure 5. In other words, the spline structure 20 is formed in a cylindrical shape as a whole. Multiple internal grooves 22A and external teeth 22B are formed on the outer circumferential surface of the spline structure 20 in an uneven manner, and the spline 22 is formed by these internal grooves 22A and external teeth 22B. The spline 22 is formed such that each of the internal grooves 22A and external teeth 22B extends in the axial direction of the spline structure 20 and is arranged at equal intervals in the circumferential direction of the spline structure 20.

[0028] The spline structure 20 is used by being inserted into the mating member 20A, which is shown by the dashed line in Figure 5. The mating member 20A is formed in a cylindrical shape into which the spline structure 20 can be inserted, and multiple internal teeth (not shown) capable of engaging with the splines 22 of the spline structure 20 are formed in an uneven manner on its inner circumferential surface. The spline structure 20 is configured to transmit power when the splines 22 mesh with the internal teeth of the mating member 20A.

[0029] Furthermore, the spline structure 20 is not limited to being formed in a cylindrical shape as a whole, but can also be formed in a columnar shape. In this case, the workpiece 21 used in the manufacture of the spline structure 20 is also cylindrical in shape.

[0030] [2] Manufacturing apparatus for spline structures The spline structure manufacturing apparatus according to the present invention is a manufacturing apparatus that manufactures a spline structure having splines by cutting the outer surface of a cylindrical or columnar workpiece with a hob cutter, A support shaft that rotatably supports the workpiece at its axial center, The hob cutter is rotatably supported around a cutter axis extending in a direction perpendicular to the support shaft, A rotating mechanism for rotating the hob cutter, A contact mechanism that brings the workpiece and the hob cutter into contact with each other, A moving mechanism for moving the hob cutter or the workpiece in the axial direction of the workpiece, The system comprises a control unit that controls the operation of the rotating mechanism, the contact mechanism, and the moving mechanism, The control unit, A conventional cutting means that performs the cutting by making the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter the same at the contact point between the workpiece and the hob cutter, The device is characterized by comprising a climb-cutting means that performs the cutting by moving the hob cutter in opposite directions relative to the workpiece and rotating the hob cutter at the point of contact between the workpiece and the hob cutter (see Figure 6).

[0031] The manufacturing apparatus 10 of the present invention is used in the manufacturing method of the spline structure described above, and is also referred to as, for example, a hobbing machine. As shown in Figure 6, the manufacturing apparatus 10 includes a support shaft 12, a hob cutter 11, and a control unit 13.

[0032] The support shaft 12 is formed in a roughly cylindrical shape and is arranged to extend in the vertical direction (the z-direction in Figure 6). The support shaft 12 is connected to a power source such as a stepping motor or servo motor (not shown), and is configured to allow adjustment of rotational speed and change of rotational direction. The workpiece 21 is fixed to the support shaft 12 and is rotatably supported around the axis Ax1 of the support shaft 12, which extends in the vertical direction (z direction in Figure 6). The hob cutter 11 is formed in a substantially cylindrical shape and has multiple cutting blades 11A on its surface. The hob cutter 11 is supported between a pair of arms 11B and is configured to rotate freely around a cutter axis Ax2 that extends in the left-right direction (y-direction in Figure 6).

[0033] The manufacturing apparatus 10 is equipped with a rotating mechanism for rotating the hob cutter 11. Specifically, the rotating mechanism has a power source such as a motor (not shown), and the hob cutter 11 is rotated by the driving force transmitted from this power source. The rotating mechanism also has a function to adjust the rotational speed of the hob cutter 11. The location of the power source is not particularly limited; for example, it can be installed inside the arm 11B and connected to the hob cutter 11, or it can be installed outside the arm 11B and connected to the hob cutter 11 via a chain, belt, or the like.

[0034] The manufacturing apparatus 10 is equipped with a contact mechanism that brings the workpiece 21 and the hob cutter 11 into contact with each other. Specifically, the contact mechanism has an extension / retraction device (not shown) such as a cylinder provided at the base of the arm 11B, and the extension / retraction of this device allows the arm 11B to move freely in the front-rear direction (the x-direction in Figure 6). The hob cutter 11, supported by the arm 11B, comes into contact with the workpiece 21 when the contact mechanism advances the arm 11B, and moves away from the workpiece 21 when the contact mechanism retracts the arm 11B.

[0035] The manufacturing apparatus 10 is equipped with a moving mechanism that moves the hob cutter 11 or the workpiece 21 in the direction of the axis Ax1 of the workpiece 21. Specifically, the moving mechanism has a lifting device (not shown) that supports the arm 11B, and the lifting operation of the lifting device allows the arm 11B to move freely in the vertical direction (z direction in Figure 6). The hob cutter 11, supported by the arm 11B, is moved upward relative to the workpiece 21 by the lifting device raising the arm 11B, and downward relative to the workpiece 21 by the lifting device lowering the arm 11B. Furthermore, the moving mechanism has the function of adjusting the relative position of the hob cutter 11 with respect to the workpiece 21 in the vertical direction (z direction in Figure 6), and the function of adjusting the moving speed when moving the hob cutter 11 in the vertical direction (z direction in Figure 6) with respect to the workpiece 21.

[0036] The control unit 13 controls the operation of the rotation mechanism, contact mechanism, and moving mechanism, and is electrically connected to them. The control unit 13, although not specifically shown, includes a computer that calculates and executes the program, a storage device for storing the program, and an input device for inputting numerical values, etc., into the storage device. The control unit 13 calculates a program using an electronic computer based on input or stored numerical values, and controls the operation of the rotating mechanism, contact mechanism, and moving mechanism according to the calculation results, and operates the hob cutter 11 via the arm 11B. The manufacturing apparatus 10 can form a spline 22 by cutting the outer surface of the workpiece 21 with the hob cutter 11 by the control unit 13 controlling the operation of the rotating mechanism, contact mechanism, and moving mechanism to operate the hob cutter 11.

[0037] The control unit 13 includes conventional cutting means and climb cutting means. The conventional cutting means is a program stored in the cutting process S10 described above to execute the conventional cutting process S11. Specifically, the conventional cutting means performs cutting by making the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 the same at the contact point CP between the workpiece 21 and the hob cutter 11 (see Figure 2). The climb-cutting means is a program stored in the cutting process S10 described above to execute the climb-cutting process S12. Specifically, the climb-cutting means performs cutting by reversing the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 at the contact point CP between the workpiece 21 and the hob cutter 11 (see Figure 3). In other words, the control unit 13 has the function of performing a conveyor cut process S11 and a climb cut process S12 according to a stored program when performing a cutting process S10 using the manufacturing apparatus 10, thereby cutting the outer surface of the workpiece 21 using two cutting methods, conveyor cut and climb cut, to form a spline 22.

[0038] Figure 7 is a flowchart showing an example of the flow of the cutting process S10 using the manufacturing apparatus 10 described above. When executing the cutting process S10, the control unit 13 moves the hob cutter 11 to the starting position in step S101. This starting position can be the starting position of the conveyor cut on the workpiece 21 (see Figure 4). The movement of the hob cutter 11 is performed by the control unit 13 controlling the operation of the movement mechanism and raising or lowering the arm 11B. In step S102, the control unit 13 brings the hob cutter 11 into contact with the workpiece 21. This contact of the hob cutter 11 with the workpiece 21 is achieved by the control unit 13 controlling the operation of the contact mechanism and advancing the arm 11B.

[0039] The control unit 13 starts the conveyor cutting in step S103. In other words, the conveyor cutting process S11 is started in step S103. Specifically, in step S103, the control unit 13 controls the operation of the rotation mechanism to rotate the hob cutter 11, thereby initiating the conveyor cut. Furthermore, during the execution of the conveyor cutting process S11 (between steps S103 and S104), the control unit 13 controls the operation of the moving mechanism and lowers the arm 11B at a constant speed, so that the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 are the same at the contact point CP between the workpiece 21 and the hob cutter 11.

[0040] The control unit 13 terminates the conveyor cut at step S104. In other words, the conveyor cut process S11 is terminated at step S104. Specifically, in step S104, the control unit 13 controls the operation of the rotation mechanism and stops the rotation of the hob cutter 11, thereby ending the conveyor cut. The end of this conveyor cut can be defined as when the hob cutter 11 reaches the base end position of the spline 22 on the outer circumferential surface of the workpiece 21, and this base end position of the spline 22 can be the starting position of the climb cut (see Figure 4).

[0041] In step S105, the control unit 13 starts the climb cut. In other words, the climb cut process S12 is started in step S105. In step S104, the hob cutter 11 stops at the base end position of the spline 22 on the outer surface of the workpiece 21, that is, at the starting position of the climb cut. Therefore, step S105 can be executed immediately after step S104. Specifically, in step S105, the control unit 13 controls the operation of the rotation mechanism to rotate the hob cutter 11, thereby initiating the climb cut. Furthermore, during the execution of the climb cut process S12 (between steps S105 and S106), the control unit 13 controls the operation of the moving mechanism and raises the arm 11B at a constant speed, thereby making the direction of movement of the hob cutter 11 relative to the workpiece 21 and the direction of rotation of the hob cutter 11 opposite at the contact point CP between the workpiece 21 and the hob cutter 11.

[0042] The control unit 13 terminates the climb cut in step S106. In other words, the climb cut process S11 is terminated in step S106. Specifically, in step S106, the control unit 13 controls the operation of the rotation mechanism to stop the rotation of the hob cutter 11, thereby ending the climb cut. The end of this climb cut can be defined as when the hob cutter 11 reaches the tip position of the spline 22 on the outer circumferential surface of the workpiece 21, that is, the tip position of the spline 22 can be defined as the end position of the climb cut (see Figure 4).

[0043] The manufacturing apparatus 10 controls the operation of the moving mechanism with the control unit 13, and can easily switch between conveyor cuts and climb cuts simply by changing the direction of movement of the hob cutter 11 relative to the workpiece 21. Furthermore, the manufacturing apparatus 10 can perform both conveyor cutting and climb cutting using the same hob cutter 11 without changing the hob cutter 11 or transporting the workpiece 21 between different devices. Furthermore, the manufacturing apparatus 10 can perform the conveyor cut and the climb cut continuously without requiring any waiting time for switching, by setting the base position of the spline 22 as the end position of the conveyor cut and the start position of the climb cut, and the tip position of the spline 22 as the end position of the climb cut, depending on the base position and tip position of the spline 22 to be formed. Therefore, the manufacturing of the spline structure 20 using the manufacturing apparatus 10 described above can be made more efficient. [Explanation of symbols]

[0044] 10; manufacturing equipment; 11; Hob cutter, 11A; Cutting blade, 11B; Arm, Ax2; Cutter shaft, 12;Support shaft, Ax1;Axis core, 13; Control unit, 20; Spline structure, 20A; Mating member, 21; Workpiece, 22; Spline, 22A; Internal groove, 22B; External tooth, S10: Cutting process, S11: Conventional cutting process, S12: Climbing cut process.

Claims

1. A manufacturing method for producing a spline structure having splines by cutting the outer surface of a cylindrical or columnar workpiece with a hob cutter, The cutting process includes a procedure in which the workpiece and the hob cutter are rotated around their respective axes, the hob cutter is brought into contact with the outer circumferential surface of the workpiece, and the hob cutter or the workpiece is moved in the axial direction of the workpiece, thereby cutting the outer circumferential surface of the workpiece with the hob cutter to form the spline, The aforementioned cutting process is A conventional cutting process in which the cutting is performed such that the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter are in the same direction at the contact point between the workpiece and the hob cutter, A method for manufacturing a spline structure, comprising: a climb-cut step, in which the cutting is performed such that the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter are opposite at the point of contact between the workpiece and the hob cutter.

2. The aforementioned cutting process is After partially forming only the ends of the spline in the conventional cutting process, The method for manufacturing a spline structure according to claim 1, wherein the entire spline is formed by overlapping the end with the climb-cut step.

3. A manufacturing apparatus for producing a spline structure having splines by cutting the outer surface of a cylindrical or columnar workpiece with a hob cutter, A support shaft that rotatably supports the workpiece at its axial center, The hob cutter is rotatably supported around a cutter axis extending in a direction perpendicular to the support shaft, A rotating mechanism for rotating the hob cutter, A contact mechanism that brings the workpiece and the hob cutter into contact with each other, A moving mechanism for moving the hob cutter or the workpiece in the axial direction of the workpiece, The system comprises a control unit that controls the operation of the rotating mechanism, the contact mechanism, and the moving mechanism, The control unit, A conventional cutting means that performs the cutting by making the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter the same at the contact point between the workpiece and the hob cutter, A spline structure manufacturing apparatus comprising a climb-cut means that performs the cutting at the point of contact between the workpiece and the hob cutter, such that the direction of movement of the hob cutter relative to the workpiece and the direction of rotation of the hob cutter are in opposite directions.

4. The spline structure manufacturing apparatus according to claim 3, wherein the control unit operates in the order of the conventional cutting means and the climb cutting means.

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