Gear cutting machine and phase alignment method thereof

Abstract

To provide a gear processing machine capable of positioning without breaking a cutter and of preventing a workpiece from being damaged, and a positioning method for the same.SOLUTION: A gear processing machine 100 which synchronously rotates a cutter 200 and a workpiece 300 and processes a gear includes: a cutter phase measurement part (a touch probe 112) detecting a phase of the cutter; a workpiece phase measurement part (a spiral current measuring instrument 122) detecting a phase of the workpiece; and a correction part 140 correcting a phase of the cutter. The correction part 140 is fitted with a dummy cutter 210 larger in toughness and lower in rigidity than the cutter to measure a phase, causes the dummy cutter 210 and the workpiece 300 to engage to position, exchanges the dummy cutter 210 for the cutter 200 to measure the phase, and corrects the phase of the cutter 200 on the basis of the phase of the dummy cutter 210.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gear cutting machine that cuts gears by rotating a cutter and a workpiece synchronously, and a phase matching method therefor. [Background technology]

[0002] In gear cutting machines, the workpiece has a gear shape, so it is necessary to know the phase of the workpiece. Patent Document 1 is known as a method for detecting the phase of the cutter and workpiece of a gear cutting machine. In Patent Document 1, a contact sensor attached to the tool spindle is driven to detect contact between the contactor and the gear, thereby detecting the phase of the gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6466633 Summary of the Invention [Problem to be solved by the invention]

[0004] In the gear manufacturing process, heat treatment after gear cutting causes distortion in the material, so further grinding or polishing is required for adjustment. When grinding, etc., a specified amount of penetration (removal allowance) is set from the edge of the workpiece and feed is applied, but because both the cutter and the workpiece are shaped like gears, the phase alignment of the cutter and workpiece is required. Alignment is performed by bringing the sides of the cutter into contact with the workpiece.

[0005] Because the material is hard after heat treatment, it is machined using a carbide cutter. While carbide materials are excellent in terms of their hardness, they have low toughness and are prone to chipping when the workpiece and the side of the cutter are brought into contact for alignment. Another problem is that the side of the workpiece (i.e., the tooth surface) is easily scratched.

[0006] Therefore, an object of the present invention is to provide a gear cutting machine and an alignment method thereof that can perform alignment without damaging the cutter and also prevent damage to the workpiece. [Means for solving the problem]

[0007] In order to solve the above problems, a typical configuration of the present invention is a gear cutting machine that machines a gear by rotating a cutter and a workpiece synchronously, comprising: a tool spindle that drives the cutter; a workpiece spindle that drives the workpiece; a cutter phase measurement unit that detects the phase of the cutter; a workpiece phase measurement unit that detects the phase of the workpiece; and a correction unit that corrects the phase of the cutter, wherein the correction unit measures the phase by attaching a dummy cutter that is tougher and lower in hardness than the cutter, meshing the dummy cutter with the workpiece to align them, replacing the dummy cutter with the cutter and measuring the phase, and correcting the phase of the cutter based on the phase of the dummy cutter.

[0008] The cutter is a super hard cutter, and the dummy cutter may be molded from high speed steel or resin.

[0009] Another representative configuration of the present invention is a phase alignment method for a gear cutting machine, which is characterized by using a gear cutting machine equipped with a tool spindle that drives a cutter, a work spindle that drives a workpiece, a cutter phase measurement unit that detects the phase of the cutter, and a workpiece phase measurement unit that detects the phase of the workpiece, attaching a dummy cutter that is tougher and lower in hardness than the cutter to measure the phase, engaging the dummy cutter with the workpiece to align them, replacing the dummy cutter with the cutter to measure the phase, and correcting the phase of the cutter based on the phase of the dummy cutter. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a gear cutting machine and a method for aligning the cutter without damaging the cutter and preventing damage to the workpiece. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a main part of a gear cutting machine according to an embodiment of the present invention. [Figure 2] 10 is a flowchart illustrating a procedure for alignment. [Figure 3] FIG. 10 is a diagram supplementing the explanation of part of the setup. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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.

[0013] 1 is a diagram illustrating the main parts of a gear cutting machine according to this embodiment. As a whole, it can be exemplified by a gear shaping center capable of skiving, but illustrations and descriptions of parts that are not related to the present invention will be omitted.

[0014] The gear cutting machine 100 is a device that machines gears by synchronously rotating a cutter and a workpiece. A cutter 200 is replaceably attached to a tool spindle 110. A workpiece 300 is replaceably attached to a workpiece spindle 120. A control unit 130 drives and controls the tool spindle 110, workpiece spindle 120, and other motors. The control unit 130 performs machining by moving the cutter 200 and workpiece 300 relative to each other while synchronously rotating the tool spindle 110 and workpiece spindle 120. Gear shaping can be performed by aligning the rotation axes of the cutter 200 and workpiece 300 parallel to each other, and skiving can be performed by tilting the axis of the cutter 200 relative to the axis of the workpiece 300.

[0015] A touch probe 112 is provided near the tool spindle 110 as an example of a cutter phase measurement unit for detecting the phase of the cutter 200. The touch probe 112 is a device that brings a ball 112a (also called a stylus) at its tip into contact with the workpiece and reads the position of the signal point in coordinates on the machine tool side. By rotating the cutter 200 at a low speed and detecting both tooth flanks, the tooth groove center can be obtained, and the phase of the tooth crest center can be obtained.

[0016] An eddy current measuring device 122, an example of a workpiece phase measuring unit, is provided near the workpiece axis 120. The eddy current measuring device 122 has a built-in sensor coil 122a at its tip, which generates a high-frequency magnetic flux. When the workpiece 300 is rotated in this magnetic field, the tooth tip approaches the sensor coil 122a and the tooth bottom moves away from the sensor coil 122a. The high-frequency magnetic flux generates eddy currents on the metal surface of the workpiece 300, and the magnitude of the current changes depending on the distance, so that the impedance of the sensor coil 122a changes from the sensor side. In other words, the change in distance can be perceived as a change in impedance, making it possible to detect the phase of the tooth tip relative to the rotation of the workpiece axis 120.

[0017] The touch probe 112 measures the external shape, so it can be made of any material. The eddy current measuring instrument 122 must generate eddy currents, so the material of the object to be measured must be a conductive, non-magnetic metal.

[0018] The control unit 130 is a computer. Each unit of the control unit 130 described below is specifically a program executed by the CPU. The tool control unit 132 controls the rotation of the servo motor of the tool spindle 110 and controls the feed of the workpiece 300. The cutter phase measurement unit 134 controls the touch probe 112 and inserts the ball 112a into the tooth groove. The workpiece control unit 136 controls the rotation of the workpiece axis 120 and moves the cutter 200 and workpiece 300 in the approaching and separating directions (changing the center distance).

[0019] The correction unit 140 corrects the phase of the cutter 200. A method for phasing the gear cutting machine performed by the correction unit 140 will now be described.

[0020] First, let us assume that the cutter 200 that actually performs the machining is a carbide cutter. This is because the material is highly hard after heat treatment. Although carbide materials are excellent in terms of their high hardness, they have a problem in that they have low toughness and are prone to chipping when the side surfaces of the workpiece 300 and cutter 200 are brought into contact for alignment. Another problem is that the side surfaces of the workpiece 300 (i.e., the tooth surfaces) are easily scratched at this time.

[0021] Therefore, in the alignment method according to the present invention, a dummy cutter 210 (see FIG. 3) is attached, the phase is measured, and the dummy cutter 210 is replaced with a cutter. The dummy cutter 210 has the same external shape as the cutter 200, but is made of a material that is tougher than the cutter 200 and less likely to chip, and has a lower hardness and is less likely to damage the workpiece 300. Specifically, high-speed steel (preferably not hardened) or a resin-molded product (manufactured by cutting or a 3D printer) can be used.

[0022] Fig. 2 is a flowchart explaining the alignment setup. Fig. 3 is a diagram supplementing the explanation of part of the setup. In Fig. 3, the dummy cutter 210 is hatched to distinguish it from the cutter 200. Below, the procedure will be explained along the flowchart in Fig. 2 with reference to the supplementary drawing in Fig. 3.

[0023] First, the dummy cutter 210 and the workpiece 300 are attached to the tool spindle 110 (S200, FIG. 3(a)). An ATC (auto tool changer, not shown) can be used to attach the dummy cutter 210. An industrial robot, not shown, can be used to attach the workpiece 300.

[0024] Next, the phase of the workpiece is measured and stored using the eddy current measuring device 122 (S202, FIG. 3(b)). The ball 112a of the touch probe 112 is inserted into the tooth groove of the dummy cutter 210, and the tool spindle 110 is rotated forward and backward at a low speed to store the phase of the tooth groove (S204, FIG. 3(b)).

[0025] Next, the dummy cutter 210 is moved to the center of the tooth width of the workpiece 300 (S206). Then, with the tooth ridges of the dummy cutter 210 facing the tooth grooves of the workpiece 300, the workpiece 300 is moved toward the dummy cutter 210, and the dummy cutter 210 and the workpiece are meshed together (S208, FIG. 3(c)). At this time, a torque limit is set in the tool spindle 110, and if they do not mesh (if the tooth tips collide), they are released and then tried again. It is during this process that carbide cutters are prone to chipping.

[0026] Once the dummy cutter 210 and the workpiece are engaged, the workpiece 300 is rotated and stopped at the zero coordinate position (S210). Then, the servo motor of the tool spindle 110 is turned on to rotate it left and right, and the phase at which the right tooth flank contacts the workpiece 300 and the phase at which the left tooth flank contacts the workpiece 300 are recorded (S212). By acquiring the phases on both the left and right sides, the phase at the center of the tooth gap can be obtained. Once the phases on both the left and right sides have been acquired, the dummy cutter 210 and the workpiece 300 are separated (S214).

[0027] Next, the dummy cutter 210 is replaced with a cutter 200 made of an ultra-hard material (S216, FIG. 3(d)). The cutter can be replaced using an ATC. Then, the groove phase of the cutter 200 is stored (S218, FIG. 3(e)) by the same operation as that for registering the dummy cutter 210 (S204).

[0028] Then, the phase of the cutter 200 is corrected using the phase of the dummy cutter 210. More specifically, based on the relationship between the initial phase of the dummy cutter 210 stored in S204 and the phase at which it contacts the left and right tooth flanks stored in S212, the phase at which it contacts the left and right tooth flanks can be obtained from the initial phase of the cutter 200 stored in S218.

[0029] In this way, alignment can be performed without contacting the cutter 200 made of ultra-hard material with the workpiece 300. This allows alignment to be performed without damaging the cutter, and also prevents damage to the workpiece.

[0030] 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 these modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0031] The present invention can be used as a gear cutting machine that cuts gears by rotating a cutter and a workpiece synchronously, and as a phase matching method for the gear cutting machine. [Explanation of symbols]

[0032] 100... gear cutting machine, 110... tool spindle, 112... touch probe, 112a... ball, 120... work shaft, 122... eddy current measuring device, 122a... sensor coil, 130... control unit, 132... tool control unit, 134... cutter phase measuring unit, 136... work control unit, 140... correction unit, 200... cutter, 210... dummy cutter, 300... work

Claims

1. In gear cutting machines that process gears by rotating the cutter and workpiece synchronously, a tool spindle that drives the cutter; a work shaft that drives the work; a cutter phase measurement unit that detects the phase of the cutter; a work phase measurement unit that detects the phase of the work; a correction unit that corrects the phase of the cutter, The correction unit a dummy cutter having the same outer shape as the cutter but higher in toughness and lower in hardness than the cutter is attached to the cutter phase measurement unit to measure the phase; The dummy cutter and the workpiece are meshed and aligned, The dummy cutter attached to the cutter phase measuring unit is replaced with the cutter to measure the phase; A gear cutting machine characterized in that the phase of the cutter is corrected based on the phase of the dummy cutter.

2. the cutter is a carbide cutter, 2. The gear cutting machine according to claim 1, wherein the dummy cutter is molded from high-speed steel or resin.

3. a tool spindle that drives the cutter; a work axis that drives the work; a cutter phase measurement unit that detects the phase of the cutter; a gear cutting machine including a workpiece phase measuring unit for detecting the phase of the workpiece, a dummy cutter having the same outer shape as the cutter but higher in toughness and lower in hardness than the cutter is attached to the cutter phase measurement unit to measure the phase; The dummy cutter and the workpiece are meshed and aligned, The dummy cutter attached to the cutter phase measuring unit is replaced with the cutter to measure the phase; A phase alignment method for a gear cutting machine, comprising correcting the phase of the cutter based on the phase of the dummy cutter.

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