Threaded grinding wheel truing method and threaded grinding wheel truing device

Abstract

To provide a truing method for a threaded grinding wheel, which can perform truing for a plurality of types of threaded grinding wheels by using one type of a rotary truer.SOLUTION: This truing method for a gear grinding threaded grinding wheel W using a rotary truer T having disc surfaces T1 and T2 orthogonal to a center axis calculates cross angles θ1 and θ2 and offset angles φ1 and φ2 between the threaded grinding wheel W and the rotary truer T in accordance with elements of the threaded grinding wheel W, and performs truing for the threaded grinding wheel W by the disc surfaces T1 and T2 of the rotary truer T in a state where the threaded grinding wheel W and the rotary truer T are arranged so as to set the cross angles θ1 and θ2 and the offset angles φ1 and φ2 which have been calculated.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for truing a threaded grinding wheel. [Background technology]

[0002] Patent Documents 1 and 2 describe a method of using a rotary truer as a method of truing a threaded grinding wheel. With the rotary truer rotating, the rotation of the threaded grinding wheel is synchronized with the relative movement of the threaded grinding wheel and the rotary truer, and the rotary truer is used to true the thread tooth flank of the threaded grinding wheel.

[0003] The rotary truer has a triangular cross section in the axial direction that tapers toward the outer periphery. The tapered cross section of the rotary truer is formed to match the specifications of the thread groove shape of the threaded grinding wheel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-089154 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-029992 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional rotary truers with tapered cross-sections are specially designed to match the specifications of the thread groove shape of a threaded grinding wheel. As a result, truing of a threaded grinding wheel requires the use of a dedicated rotary truer for each threaded grinding wheel. This results in high tool costs.

[0006] The present invention has been made in consideration of such problems, and aims to provide a method and apparatus for truing threaded grinding wheels that enables truing of multiple types of threaded grinding wheels using a single type of rotary truer. [Means for solving the problem]

[0007] One aspect of the present invention is a method for truing a threaded grinding wheel for gear grinding using a rotary truer, comprising: The rotary trunnion has a disk surface perpendicular to the central axis, calculating a crossing angle and an offset angle between the threaded grinding wheel and the rotary truer according to the specifications of the threaded grinding wheel; The method for truing a threaded grinding wheel includes arranging the threaded grinding wheel and the rotary truer so as to obtain the calculated crossing angle and offset angle, and then truing the threaded grinding wheel using the disk surface of the rotary truer.

[0008] Another aspect of the present invention is a truing device that uses a rotary truer to true a threaded grinding wheel for gear grinding, comprising: The rotary trunnion has a disk surface perpendicular to the central axis, a calculation unit that calculates a crossing angle and an offset angle between the threaded grinding wheel and the rotary truer in accordance with specifications of the threaded grinding wheel; a control unit that performs truing of the threaded grinding wheel using the disk surface of the rotary truer in a state in which the threaded grinding wheel and the rotary truer are arranged so as to achieve the calculated crossing angle and offset angle; The present invention relates to a truing device for a threaded grinding wheel, comprising: [Effects of the Invention]

[0009] According to the above-described truing method and truing device, the rotary truer has a disk surface perpendicular to the central axis of the rotary truer. Therefore, the rotary truer has a shape that is unrelated to the specifications of the thread groove shape of the threaded grinding wheel, and can be applied to truing threaded grinding wheels of different shapes.

[0010] In order to perform truing using the disk surface of the rotary truer, the threaded grinding wheel and the rotary truer are positioned so that a predetermined cross angle and a predetermined offset angle are achieved during truing. The predetermined cross angle and the predetermined offset angle are calculated according to the specifications of the threaded grinding wheel. In other words, by positioning the threaded grinding wheel and the rotary truer during truing so that the cross angle and offset angle are appropriate for the threaded grinding wheel to be trued, it is possible to true a variety of threaded grinding wheels.

[0011] As described above, according to the above-described aspects, it is possible to provide a method and apparatus for truing a threaded grinding wheel that allows truing of a plurality of types of threaded grinding wheels using one type of rotary truer. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a truing device. [Figure 2] FIG. 10 is a diagram showing a threaded grinding wheel and a rotary truer when truing a first thread tooth flank of the threaded grinding wheel. [Figure 3] FIG. 3 is a view seen from the direction III in FIG. 2. [Figure 4] FIG. 3 is a view seen from the direction IV in FIG. 2. [Figure 5] FIG. 10 is a diagram showing a threaded grinding wheel and a rotary truer when truing the second thread tooth flank of the threaded grinding wheel. [Figure 6] FIG. 6 is a view seen from the direction VI in FIG. 5. [Figure 7] FIG. 7 is a view seen from the VII direction in FIG. 5. [Figure 8]10 is a flowchart showing processing by a calculation unit of the truing device. [Figure 9] FIG. 9 is a diagram for explaining the process of S6 in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Embodiment) 1. Configuration of truing device 1 A truing device 1 for a threaded grinding wheel W will be described with reference to Fig. 1. The truing device 1 is a device for truing a threaded grinding wheel W, which is a workpiece, using a rotary truer T. In detail, the truing device 1 rotates the rotary truer T about its central axis Ct and rotates the threaded grinding wheel W about its central axis Cw, and then moves the rotary truer T in the direction of the central axis Cw of the threaded grinding wheel W relative to the threaded grinding wheel W, thereby trueing the thread tooth flank of the threaded grinding wheel W.

[0014] Therefore, the truing device 1 is equipped with three linear motion devices configured to be able to linearly move the threaded grinding wheel W and the rotary truer T relative to each other in three mutually intersecting axial directions. In this embodiment, the three linear motion devices of the truing device 1 are able to linearly move the threaded grinding wheel W and the rotary truer T relative to each other in each of the three mutually orthogonal axial directions of the Xt axis, the Yt axis, and the Zt axis.

[0015] Furthermore, the truing device 1 is equipped with a rotation device configured to rotate at least one of the threaded grinding wheel W and the rotary truer T in order to change the relative position between the threaded grinding wheel W and the rotary truer T. In this embodiment, the rotation device of the truing device 1 is configured to rotate the threaded grinding wheel W around the B axis parallel to the Yt axis.

[0016] The truing device 1 also includes a rotation device configured to rotate the threaded grinding wheel W around the central axis Cw of the threaded grinding wheel W. In this embodiment, the central axis Cw of the threaded grinding wheel W is an axis perpendicular to the Yt axis. The truing device 1 also includes a rotation device configured to rotate the rotary truer T around the central axis Ct of the rotary truer T. In this embodiment, the central axis Ct of the rotary truer T is an axis parallel to the Zt axis.

[0017] In this embodiment, as shown in Fig. 1, the Xt-axis direction and the Zt-axis direction are horizontal, and the Yt-axis direction is vertical. However, the Xt-axis, Yt-axis, and Zt-axis may be configured differently from Fig. 1 in terms of the horizontal and vertical directions. Also, the configuration for changing the relative positions of the threaded grinding wheel W and the rotary tourer T may be configured differently from Fig. 1.

[0018] In this embodiment, the truing apparatus 1 includes a bed 10, a workpiece holding device 20, a tool holding device 30, a control unit 40, and a calculation unit 50. The bed 10 is installed on an installation surface and formed into a shape corresponding to the shapes of the workpiece holding device 20 and the tool holding device 30. The bed 10 is, for example, rectangular. On the upper surface of the bed 10, a pair of Xt-axis guide surfaces 11 extending in the Xt-axis direction and a pair of Zt-axis guide surfaces 12 extending in the Zt-axis direction are formed.

[0019] The workpiece holding device 20 allows a threaded grinding wheel W, which is a workpiece, to move linearly in the Xt-axis direction and to rotate about the B-axis and Cw-axis relative to the bed 10. The workpiece holding device 20 mainly comprises an Xt-axis moving table 21, a B-axis rotating table 22, and a workpiece spindle device 23.

[0020] The Xt-axis moving table 21 constitutes one of the linear motion devices. The Xt-axis moving table 21 is driven by a driving device such as a linear motor or a ball screw mechanism (not shown), and moves in the Xt-axis direction while being guided by the Xt-axis guide surface 11 of the bed 10.

[0021] The B-axis rotating table 22 constitutes a rotating device for changing the relative position of the threaded grinding wheel W and the rotary tourer T. The B-axis rotating table 22 is installed on the upper surface of the Xt-axis moving table 21 and moves in the Xt-axis direction integrally with the Xt-axis moving table 21. The B-axis rotating table 22 is also provided so as to be rotatable about the B-axis relative to the Xt-axis moving table 21. A rotary motor (not shown) is housed in the B-axis rotating table 22, and the B-axis rotating table 22 can be rotated about the B-axis by driving the rotary motor.

[0022] The workpiece spindle device 23 constitutes a rotating device that can rotate the threaded grinding wheel W about the central axis Cw of the threaded grinding wheel W. The workpiece spindle device 23 is provided on the B-axis rotary table 22 and rotates about the B-axis integrally with the B-axis rotary table 22. The workpiece spindle device 23 rotatably holds the threaded grinding wheel W. The workpiece spindle device 23 is driven by a rotary motor to rotate the threaded grinding wheel W about the Cw-axis. In this way, the workpiece holding device 20 enables the threaded grinding wheel W to move in the Xt-axis direction relative to the bed 10 and to rotate about the B-axis and the Cw-axis.

[0023] In detail, the workpiece spindle device 23 includes a housing 23a and a spindle 23b. The housing 23a of the workpiece spindle device 23 is fixed to the B-axis rotary table 22, and the spindle 23b of the workpiece spindle device 23 is rotatably supported by the housing 23a. A threaded grinding wheel W is coaxially attached to the tip of the spindle 23b. In other words, the threaded grinding wheel W is cantilevered by the spindle 23b of the workpiece spindle device 23. However, the workpiece spindle device 23 may be configured to support the threaded grinding wheel W in a doubly supported manner.

[0024] The tool holding device 30 mainly comprises a column 31, a saddle 32, and a tool spindle device 33. The column 31 constitutes one of the linear motion devices. The column 31 is driven by a driving device such as a linear motor or a ball screw mechanism (not shown), and moves in the Zt axis direction while being guided by the Zt axis guide surface 12 of the bed 10. A Yt axis guide surface 31a is formed on the surface of the column 31 that extends in the vertical direction (the left surface in FIG. 1). The saddle 32 constitutes one of the linear motion devices. The saddle 32 is driven by a driving device such as a linear motor or a ball screw mechanism (not shown), and moves in the Yt axis direction while being guided by the Yt axis guide surface 31a of the column 31.

[0025] The tool spindle unit 33 is mounted on the saddle 32 and moves integrally with the saddle 32 in the Yt-axis direction. The tool spindle unit 33 holds the rotary tourer T. A rotary motor (not shown) is housed in the tool spindle unit 33, and the tool spindle unit 33 is capable of rotating the rotary tourer T about the Ct-axis when driven by the rotary motor. In this way, the tool holding device 30 holds the rotary tourer T so that it can move in the Yt-axis and Zt-axis directions relative to the bed 10 and can rotate about the Ct-axis.

[0026] More specifically, the tool spindle unit 33 includes a housing 33a and a spindle 33b. The housing 33a of the tool spindle unit 33 is fixed to the saddle 32, and the spindle 33b of the tool spindle unit 33 is rotatably supported by the housing 33a. A rotary truer T is attached to the tip of the spindle 33b. In other words, the rotary truer T is cantilevered by the spindle 33b of the tool spindle unit 33.

[0027] In the above, an example has been given in which the workpiece holding device 20 holds the threaded grinding wheel W, and the tool holding device 30 holds the rotary truer T. Alternatively, the truing device 1 can be configured such that the tool holding device 30 holds the threaded grinding wheel W, and the workpiece holding device 20 holds the rotary truer T.

[0028] The control unit 40 is equipped with an arithmetic processing unit (processor) and a storage device, and controls each of the drive devices by executing a truing program. In other words, the control unit 40 controls the rotation of the rotary truer T, the rotation of the threaded grinding wheel W, which is the workpiece, and the relative movement between the threaded grinding wheel W and the rotary truer T. In order to true the thread tooth flank of the threaded grinding wheel W, the control unit 40 controls each of the drive devices while synchronously controlling the rotation of the workpiece spindle unit 23 and the tool spindle unit 33.

[0029] The calculation unit 50 particularly calculates the crossing angles θ1, θ2 and offset angles φ1, φ2 described below as conditions for truing the thread tooth flank of the threaded grinding wheel W using the rotary truer T. The calculation unit 50 includes an arithmetic processing unit (processor) and a storage device. The calculation unit 50 may be configured as a device integrated with the control unit 40, or may be configured as a device separate from the control unit 40.

[0030] 2. Defining the coordinate system A coordinate system for truing the thread tooth flank of the threaded grinding wheel W will be defined below. The definition of the coordinate system will be explained with reference to FIG.

[0031] The central axis of the threaded grinding wheel W is defined as the Zw axis. In other words, the Zw axis coincides with the Cw axis in the truing apparatus 1 shown in FIG. 1. Axes that are perpendicular to the Zw axis and perpendicular to each other are defined as the Xw axis and the Yw axis. However, in this embodiment, the Xw axis and the Zw axis are defined as horizontal directions, and the Yw axis is defined as vertical direction. Therefore, the Yw axis is an axis parallel to the Yt axis in the truing apparatus 1 shown in FIG. 1.

[0032] The central axis of the rotary truer T is defined as the Zt axis. That is, the Zt axis coincides with the Ct axis in the truing device 1 shown in FIG. 1. Axes that are perpendicular to the Zt axis and perpendicular to each other are defined as the Xt axis and the Yt axis. In this embodiment, however, the Xt axis and the Zt axis are defined as horizontal directions, and the Yt axis is defined as vertical directions. The reference origin on the central axis Zt of the rotary truer T is defined as T0. In FIG. 2, the reference origin T0 on the central axis Zt of the rotary truer T is the intersection of the Xt axis, the Yt axis, and the Zt axis. For example, the Xt axis and the Yt axis may be located on the first disc surface T1 or the second disc surface T2 of the rotary truer T, or at an intermediate position between the first disc surface T1 and the second disc surface T2.

[0033] 3. Shape of threaded grinding wheel W The shape of the threaded grinding wheel W will be described with reference to Fig. 2. Fig. 2 shows a threaded grinding wheel W with a single thread. However, the threaded grinding wheel W to be trued can also be a multiple-start thread.

[0034] The threaded grinding wheel W has, on its outer circumferential surface, a first thread tooth flank W1 facing one side in the direction of the central axis Zw (the left side in FIG. 2), and a second thread tooth flank W2 facing the other side in the direction of the central axis Zw (the right side in FIG. 2). The specifications of the threaded grinding wheel W are as follows:

[0035] The threaded grinding wheel W has an outer diameter Do and a reference circle diameter Ds. The first thread flank W1 has a transverse pressure angle α1, and the second thread flank W2 has a transverse pressure angle α2. The transverse pressure angles α1 and α2 are pressure angles in a cross section of the threaded grinding wheel W in the direction of the central axis Zw. The lead angle (also called the lead angle) of the threaded grinding wheel W is γ.

[0036] The threaded grinding wheel W is used as a tool for grinding a gear G (not shown). The above-mentioned specifications of the threaded grinding wheel W are determined by the specifications of the gear G to be ground. The specifications of the gear G to be ground include the normal pressure angle αgn, helix angle βg, module Mg, transverse pressure angle αgt, reference diameter Dgs, addendum Hg, etc.

[0037] 4. Shape of Rotary Truer T The shape of the rotary truer T will be described with reference to Fig. 2. The rotary truer T has disk surfaces T1 and T2 that are perpendicular to the central axis Zt. In this embodiment, the rotary truer T has a first disk surface T1 whose normal is at the base end side, which is the spindle 33b side of the tool spindle unit 33, and a second disk surface T2 whose normal is at the tip side, which is the free end side. In other words, the first disk surface T1 and the second disk surface T2 are facing back to back, and the normals of both surfaces coincide with the central axis Zt of the rotary truer T.

[0038] The first disc surface T1 and the second disc surface T2 of the rotary truer T are the areas where truing is performed. Here, the rotary truer T has a predetermined thickness (width of the outer peripheral surface) corresponding to the distance between the first disc surface T1 and the second disc surface T2. The thickness of the rotary truer T is set so as not to interfere with areas of the threaded grinding wheel W that are the target of truing that are not being trued. In addition, the outer peripheral surface of the rotary truer T is formed into a cylindrical shape.

[0039] 5. Defining a Predetermined Reference Axis The predetermined reference axis is used to define the relative positions of the threaded grinding wheel W and the rotary truer T during truing, which will be described below. The predetermined reference axis is an axis perpendicular to the central axis Zw of the threaded grinding wheel W. In FIG. 2, the predetermined reference axis is the Yw axis. In other words, the predetermined reference axis Yw is an axis perpendicular to the central axis Zw of the threaded grinding wheel W, passes through the central axis Zw, and is parallel to the vertical direction.

[0040] 6. Truing method for the first thread tooth flank W1 of the threaded grinding wheel W Next, a method for truing the first thread tooth flank W1 of the threaded grinding wheel W using the rotary truer T will be described with reference to FIGS.

[0041] As shown in Figures 2 to 4, truing of the first thread tooth flank W1 is performed by the first disk surface T1 of the rotary truer T in a state in which the threaded grinding wheel W and the rotary truer T are positioned so that the positional relationship between the threaded grinding wheel W and the rotary truer T is such that the crossing angle θ1 and the offset angle φ1 are established. The crossing angle θ1 and the offset angle φ1 are calculated by a calculation unit 50 shown in Figure 1. This will be explained in detail below.

[0042] As shown in Fig. 2, the threaded grinding wheel W and the rotary truer T are projected in a direction perpendicular to the central axis Zw of the threaded grinding wheel W and perpendicular to a predetermined reference axis Yw. In other words, the threaded grinding wheel W and the rotary truer T are projected in the Xw direction. At this time, as shown in Fig. 2, the central axis Zw of the threaded grinding wheel W and the central axis Zt of the rotary truer T are positioned parallel to each other. Using this state as a reference, the crossing angle θ1 and the offset angle φ1 will be explained below.

[0043] First, the crossing angle θ1 will be explained. The threaded grinding wheel W and the rotary truer T are projected in the direction of a predetermined reference axis Yw. FIG. 3 shows the state in which the threaded grinding wheel W and the rotary truer T are projected in the direction of the predetermined reference axis Yw. When projected in the direction of the predetermined reference axis Yw, the angle formed by the central axis Zw of the threaded grinding wheel W and the central axis Zt of the rotary truer T is the crossing angle θ1. In other words, as shown in FIG. 3, the rotary truer T is disposed relative to the threaded grinding wheel W at a crossing angle θ1.

[0044] Here, the crossing angle θ1 is set by a rotation device configured to rotate at least one of the threaded grinding wheel W and the rotary truer T about an axis parallel to a predetermined reference axis Yw. In the truing device 1 shown in Fig. 1, the crossing angle θ1 is set by a B-axis rotating table 22 that can rotate the threaded grinding wheel W about the B-axis.

[0045] Next, the offset angle φ1 will be explained. The threaded grinding wheel W and the rotary truer T are projected in the direction of the central axis Zw of the threaded grinding wheel W. FIG. 4 shows the state in which the threaded grinding wheel W and the rotary truer T are projected in the direction of the central axis Zw of the threaded grinding wheel W. When projected in the direction of the central axis Zw, the angle between a predetermined reference axis Yw and an axis (dashed line in FIG. 4) that is perpendicular to the central axis Zw of the threaded grinding wheel W and passes through the reference origin T0 of the rotary truer T is the offset angle φ1. As shown in FIG. 4, the rotary truer T is positioned with an offset angle φ1 relative to the threaded grinding wheel W.

[0046] Here, the offset angle φ1 is set by at least one of three linear motion devices configured to be able to linearly move the threaded grinding wheel W and the rotary truer T relative to one another in three mutually intersecting axial directions. In the truing device 1 shown in Fig. 1, the offset angle φ1 is set by an Xt-axis moving table that can linearly move the threaded grinding wheel W on the Xt-axis, and a saddle 32 that can linearly move the rotary truer T on the Yt-axis.

[0047] As shown in Figures 2 to 4, when the threaded grinding wheel W and the rotary truer T are arranged so that the cross angle θ1 and the offset angle φ1 are formed, the portion of the outer peripheral end of the rotary truer T that trues the threaded grinding wheel W is P1.

[0048] The threaded grinding wheel W and the rotary truer T are arranged to have a crossing angle θ1 and an offset angle φ1, so that at the truing position, the first disk surface T1 of the rotary truer T coincides with the first thread flank W1 of the threaded grinding wheel W. In this state, the rotary truer T is moved relatively in the direction of the central axis Zw of the threaded grinding wheel W. This causes the first disk surface T1 of the rotary truer T to true the first thread flank W1 of the threaded grinding wheel W. The trued first thread flank W1 has a transverse pressure angle α1.

[0049] 7. Truing method for the second thread tooth flank W2 of the threaded grinding wheel W Next, a method for truing the second thread tooth flank W2 of the threaded grinding wheel W using the rotary truer T will be described with reference to FIGS.

[0050] As shown in Figures 5 to 7, truing of the second thread tooth flank W2 is performed by the second disk surface T2 of the rotary truer T in a state in which the threaded grinding wheel W and the rotary truer T are positioned so that the positional relationship between the threaded grinding wheel W and the rotary truer T is such that the crossing angle θ2 and the offset angle φ2 are achieved. The crossing angle θ2 and the offset angle φ2 are calculated by the calculation unit 50 shown in Figure 1. This will be explained in detail below.

[0051] As shown in Fig. 5, the threaded grinding wheel W and the rotary truer T are projected in a direction perpendicular to the central axis Zw of the threaded grinding wheel W and perpendicular to a predetermined reference axis Yw. In other words, the threaded grinding wheel W and the rotary truer T are projected in the Xw direction. At this time, as shown in Fig. 5, the central axis Zw of the threaded grinding wheel W and the central axis Zt of the rotary truer T are positioned parallel to each other. Using this state as a reference, the crossing angle θ2 and the offset angle φ2 will be explained below.

[0052] First, the crossing angle θ2 will be explained. The threaded grinding wheel W and the rotary truer T are projected in the direction of a predetermined reference axis Yw. FIG. 6 shows the state in which the threaded grinding wheel W and the rotary truer T are projected in the direction of the predetermined reference axis Yw. When projected in the direction of the predetermined reference axis Yw, the angle formed by the central axis Zw of the threaded grinding wheel W and the central axis Zt of the rotary truer T is the crossing angle θ2. In other words, as shown in FIG. 6, the rotary truer T is positioned relative to the threaded grinding wheel W at a crossing angle θ2.

[0053] Here, the crossing angle θ2 is set by a rotation device configured to rotate at least one of the threaded grinding wheel W and the rotary truer T about an axis parallel to a predetermined reference axis Yw. In the truing device 1 shown in Fig. 1, the crossing angle θ2 is set by a B-axis rotating table 22 that can rotate the threaded grinding wheel W about the B-axis.

[0054] Next, the offset angle φ2 will be explained. The threaded grinding wheel W and the rotary truer T are projected in the direction of the central axis Zw of the threaded grinding wheel W. FIG. 7 shows the state in which the threaded grinding wheel W and the rotary truer T are projected in the direction of the central axis Zw of the threaded grinding wheel W. When projected in the direction of the central axis Zw, the angle between a predetermined reference axis Yw and an axis (dashed line in FIG. 7) that is perpendicular to the central axis Zw of the threaded grinding wheel W and passes through the reference origin T0 of the rotary truer T is the offset angle φ2. As shown in FIG. 7, the rotary truer T is positioned with an offset angle φ2 relative to the threaded grinding wheel W.

[0055] Here, the offset angle φ2 is set by at least one of three linear motion devices configured to be able to linearly move the threaded grinding wheel W and the rotary truer T relative to one another in three mutually intersecting axial directions. In the truing device 1 shown in Fig. 1, the offset angle φ2 is set by an Xt-axis moving table that can linearly move the threaded grinding wheel W on the Xt-axis, and a saddle 32 that can linearly move the rotary truer T on the Yt-axis.

[0056] As shown in Figures 5 to 7, when the threaded grinding wheel W and the rotary truer T are arranged so that the cross angle θ2 and the offset angle φ2 are formed, the portion of the outer peripheral end of the rotary truer T that trues the threaded grinding wheel W is P2.

[0057] The threaded grinding wheel W and the rotary truer T are arranged to have a crossing angle θ2 and an offset angle φ2, so that at the truing position, the second disk surface T2 of the rotary truer T coincides with the second thread flank W2 of the threaded grinding wheel W. In this state, the rotary truer T is moved relatively in the direction of the central axis Zw of the threaded grinding wheel W. This causes the second disk surface T2 of the rotary truer T to true the second thread flank W2 of the threaded grinding wheel W. The trued second thread flank W2 has a transverse pressure angle α2.

[0058] Here, as shown in Figures 3 and 6, the crossing angle θ1 when truing the first thread flank W1 and the crossing angle θ2 when truing the second thread flank W2 are the same angle. On the other hand, as shown in Figures 4 and 7, the offset angle φ1 when truing the first thread flank W1 and the offset angle φ2 when truing the second thread flank W2 are different angles. However, the absolute values ​​of the offset angles φ1 and φ2 are the same except for special cases where the normal pressure angle αgn (or transverse pressure angle αgt) of the gear G is different on the left and right tooth flanks. The rotational directions of the offset angle φ1 and the offset angle φ2 are opposite to each other.

[0059] 8. Processing by Calculation Unit 50 The processing by the calculation unit 50 shown in Fig. 1 will be described with reference to Fig. 8 and Fig. 9. As described above, the calculation unit 50 calculates, as conditions for truing the thread tooth flank of the threaded grinding wheel W using the rotary truer T, in particular, the crossing angles θ1 and θ2 and the offset angles φ1 and φ2, which will be described later.

[0060] The calculation unit 50 first acquires basic information for calculation (S1). The basic information includes the specifications of the threaded grinding wheel W and the specifications of a gear G (not shown) to be ground by the threaded grinding wheel W. In this embodiment, the basic information includes the module Mg, normal pressure angle αgn, helix angle βg, addendum Hg of the gear G, and the outer diameter Do and number of threads of the threaded grinding wheel W.

[0061] Next, the calculation unit 50 calculates the transverse pressure angle αgt of the gear G based on the normal pressure angle αgn and helix angle βg of the gear G (S2). However, if the transverse pressure angle αgt of the gear G is included in the basic information, the calculation unit 50 only needs to acquire the transverse pressure angle αgt. Here, the transverse pressure angle αgt of the gear G is equal to the absolute value of the transverse pressure angles α1 and α2 of the threaded grinding wheel W. However, in a special case where the transverse pressure angle αgt of the gear G is different on the left and right tooth flanks, the transverse pressure angle αgt of each of the left and right tooth flanks is equal to the absolute value of either the transverse pressure angle α1 or α2 of the threaded grinding wheel W.

[0062] Next, the calculation unit 50 calculates the reference circle diameter Ds of the threaded grinding wheel W based on the outer diameter Do of the threaded grinding wheel W and the addendum Hg of the gear G (S3). However, if the basic information includes the reference circle diameter Ds of the threaded grinding wheel W, the calculation unit 50 only needs to acquire the reference circle diameter Ds.

[0063] Next, the calculation unit 50 calculates the lead angle γ of the threaded grinding wheel W based on the reference circle diameter Ds and the number of threads of the threaded grinding wheel W, and the module Mg of the gear G (S4). However, if the lead angle γ of the threaded grinding wheel W is included in the basic information, the calculation unit 50 only needs to acquire the lead angle γ.

[0064] Next, the calculation unit 50 calculates the unit vector Vt of the central axis of the rotary truer T in the three-dimensional coordinate system (Xw, Yw, Zw) of the threaded grinding wheel W based on the transverse pressure angle αgt of the gear G and the lead angle γ of the threaded grinding wheel W (S5). Note that the transverse pressure angle αgt of the gear G is equal to the absolute value of the transverse pressure angles α1, α2 of the threaded grinding wheel W, except for special cases where the transverse pressure angle αgt is different on the left and right tooth flanks, as described above. In special cases where the transverse pressure angle αgt of the gear G is different on the left and right tooth flanks, the transverse pressure angle αgt of each of the left and right tooth flanks is equal to the absolute value of either the transverse pressure angle α1, α2 of the threaded grinding wheel W.

[0065] The unit vector Vt of the central axis of the rotary truer T is shown in Figure 9. In calculating the unit vector Vt, it is assumed that the portion P0 of the outer peripheral end of the rotary truer T that trues the threaded grinding wheel W is located on the Yw axis, and that the first disk surface T1 of the rotary truer T coincides with the first thread tooth flank W1 of the threaded grinding wheel W. The unit vector of the central axis of the rotary truer T in this state is defined as Vt.

[0066] Next, the calculation unit 50 calculates the crossing angles θ1, θ2 and the offset angles φ1, φ2 using three-dimensional vector calculation or three-dimensional CAD model analysis (S6). Specifically, the calculation unit 50 rotates the unit vector Vt of the central axis of the rotary truer T around the central axis of the threaded grinding wheel W in a three-dimensional coordinate system (Xw, Yw, Zw) of the threaded grinding wheel W as shown in Fig. 9. Then, it calculates the rotation angle at which the Yw direction component of the unit vector Vt becomes zero.

[0067] In Figure 9, when the rotary tourer T rotates by a rotation angle φ1, the unit vector Vt1 of the central axis has a Yw direction component of zero and is a vector parallel to the Xw-Zw plane. The rotation angle φ1 at this time is the offset angle φ1.

[0068] Furthermore, when the threaded grinding wheel W and the rotary truer T are projected in the direction of a predetermined reference axis Yw in a state in which the Yw-direction component of the unit vector Vt1 is zero, the angle formed by the central axis of the threaded grinding wheel W and the central axis of the rotary truer T is the crossing angle θ1. In this manner, the calculation unit 50 calculates the crossing angle θ1 and the offset angle φ1. When the second thread flank W2 of the threaded grinding wheel W is trued by the second disk surface T2 of the rotary truer T, the crossing angle θ2 and the offset angle φ2 are calculated by a similar process.

[0069] 9.Effects As described above, the truing device 1 of this embodiment uses a rotary truer T having disk surfaces T1, T2 perpendicular to the central axis Ct to true a threaded grinding wheel W for gear grinding. Then, a calculation unit 50 of the truing device 1 calculates crossing angles θ1, θ2 and offset angles φ1, φ2 between the threaded grinding wheel W and the rotary truer T according to the specifications of the threaded grinding wheel W. A control unit 40 of the truing device 1 positions the threaded grinding wheel W and the rotary truer T so as to achieve the calculated crossing angles θ1, θ2 and offset angles φ1, φ2, and then trues the threaded grinding wheel W using the disk surfaces T1, T2 of the rotary truer T.

[0070] As described above, the rotary truer T has disk surfaces T1 and T2 that are perpendicular to the central axis Ct of the rotary truer T. Therefore, the rotary truer T has a shape that is unrelated to the specifications of the thread groove shape of the threaded grinding wheel W, and can be applied to truing of threaded grinding wheels W of different shapes.

[0071] In order to perform truing using the disk surfaces T1, T2 of the rotary truer T, the threaded grinding wheel W and the rotary truer T are positioned so that predetermined crossing angles θ1, θ2 and predetermined offset angles φ1, φ2 are achieved during truing. The predetermined crossing angles θ1, θ2 and predetermined offset angles φ1, φ2 are calculated according to the specifications of the threaded grinding wheel W. In other words, by positioning the threaded grinding wheel W and the rotary truer T during truing so that the crossing angles θ1, θ2 and offset angles φ1, φ2 are achieved according to the threaded grinding wheel W to be trued, it is possible to true a variety of threaded grinding wheels W.

[0072] Therefore, according to the truing device 1 of this embodiment, it is possible to perform truing of a plurality of types of threaded grinding wheels W using one type of rotary truer T. [Explanation of symbols]

[0073] 1. Truing device for threaded grinding wheels 40 Control Unit 50 Calculation Unit T Rotary Truer T1, T2 disk surface W Threaded Grinding Wheel θ1,θ2 crossing angles φ1,φ2 offset angle

Claims

1. A method for truing a threaded grinding wheel for gear grinding using a rotary truer, comprising: The rotary trunnion has a disk surface perpendicular to the central axis, calculating a crossing angle and an offset angle between the threaded grinding wheel and the rotary truer according to the specifications of the threaded grinding wheel; A method for truing a threaded grinding wheel, in which the threaded grinding wheel and the rotary truer are positioned so as to achieve the calculated crossing angle and offset angle, and the threaded grinding wheel is trued using the disk surface of the rotary truer.

2. the central axis of the threaded grinding wheel is parallel to the central axis of the rotary tool when projected in a direction perpendicular to the central axis of the threaded grinding wheel and perpendicular to a predetermined reference axis perpendicular to the central axis of the threaded grinding wheel; the crossing angle is an angle formed between the central axis of the threaded grinding wheel and the central axis of the rotary truer when projected in the predetermined reference axis direction, 2. The method for truing a threaded grinding wheel according to claim 1, wherein the offset angle is an angle formed between the predetermined reference axis and an axis that is perpendicular to the central axis of the threaded grinding wheel and passes through a reference origin on the central axis of the rotary truer, when projected in the direction of the central axis of the threaded grinding wheel.

3. The truing method for a threaded grinding wheel according to claim 1 or 2, wherein the specifications of the threaded grinding wheel include a front pressure angle and a lead angle of the threaded grinding wheel.

4. 4. The truing method for a threaded grinding wheel according to claim 3, wherein the front pressure angle and lead angle of the threaded grinding wheel are determined based on the specifications of a gear to be ground by the threaded grinding wheel.

5. the offset angle is different between one thread flank and the other thread flank of the threaded grinding wheel; The truing method for a threaded grinding wheel according to any one of claims 1 to 4, wherein the crossing angle is an angle different from a lead angle of the threaded grinding wheel, and is the same angle on the one thread tooth flank and the other thread tooth flank of the threaded grinding wheel.

6. A truing device that uses a rotary truer to true a threaded grinding wheel for gear grinding, The rotary trunnion has a disk surface perpendicular to the central axis, a calculation unit that calculates a crossing angle and an offset angle between the threaded grinding wheel and the rotary truer in accordance with specifications of the threaded grinding wheel; a control unit that performs truing of the threaded grinding wheel using the disk surface of the rotary truer in a state in which the threaded grinding wheel and the rotary truer are arranged so as to achieve the calculated crossing angle and offset angle; A truing device for a threaded grinding wheel, comprising:

7. the central axis of the threaded grinding wheel is parallel to the central axis of the rotary tool when projected in a direction perpendicular to the central axis of the threaded grinding wheel and perpendicular to a predetermined reference axis perpendicular to the central axis of the threaded grinding wheel; the crossing angle is an angle formed between the central axis of the threaded grinding wheel and the central axis of the rotary truer when projected in the predetermined reference axis direction, the offset angle is an angle formed between the predetermined reference axis and an axis that is perpendicular to the central axis of the threaded grinding wheel and passes through a reference origin on the central axis of the rotary tool when projected in the direction of the central axis of the threaded grinding wheel; moreover, a rotation device configured to rotate at least one of the threaded grinding wheel and the rotary truer about an axis parallel to the predetermined reference axis; three linear motion devices configured to be able to linearly move the threaded grinding wheel and the rotary truer relatively in three mutually intersecting axial directions; Equipped with the crossing angle is set by the rotation device; 7. The truing device for a threaded grinding wheel according to claim 6, wherein the offset angle is set by at least one of the three linear motion devices.

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