1. A method for shaping and trimming the drum-shaped worm grinding wheel for grinding face gear features that on ordinary worm grinding wheel gear grinder, the diamond roller is arranged just above the grinding wheel to make the worm grinding wheel rotate in O direction on vertical plane_sThe eccentric swinging is carried out as the center, and the shaping and trimming of the drum-shaped worm grinding wheel are completed through the relative arc swinging between the drum-shaped worm grinding wheel and the shaping diamond roller.

2. The method of claim 1, wherein the eccentric swing of the worm grinding wheel in the vertical plane is divided into two movements based on the virtual center distance machining principle, one being the grinding wheel center O around the axis a1_AThe second is the translation of the grinding wheel on the Y-Z plane.

3. The method of claim 2, wherein the rotation of the grinding wheel is carried out by a grinding wheel rotation axis B1, and the grinding wheel rotates around O_AThe rotation of the grinding wheel is realized by a tool rest rotating shaft A1, the translation of the grinding wheel on a Y-Z plane is realized by a tangential feed shaft Y1 and an axial feed shaft Z1 together, four-axis linkage of B1, A1, Y1 and Z1 is controlled, the grinding wheel rotates at a constant speed and eccentrically swings relative to a roller, and thus a drum-shaped worm helicoid is trimmed.

4. The method of claim 1, wherein for dressing the grinding wheel on the normal cross-section, when dressing the crowned worm grinding wheel, the dressing diamond roller is swung around the vertical direction by an angle λ through the C2 axis, λ being the nominal helix angle of the crowned worm grinding wheel, and the calculation formula is as follows:

in the formula, n_wThe number of the worm heads, r is the reference circle radius of the pinion cutter corresponding to the drum worm grinding wheel, and z_sThe number of teeth of the gear shaping cutter corresponding to the drum-shaped worm grinding wheel is shown, and E is the axial distance between the worm grinding wheel and the corresponding gear shaping cutter.

5. The method of claim 1, wherein the method of calculating the stroke relationship between the axes B1, a1, Y1 and Z1 in the linkage process comprises: selecting stroke to calculate initial point, marking the initial point as '0', wherein the grinding wheel tool rest is horizontal at the initial point, and the center O of the grinding wheel is horizontal_wAnd the center O of the roller_dIn the vertical direction, the grinding wheel and the roller are in the correct mounting position, so that the B1 shaft drives the worm grinding wheel to rotate by any angle delta B relative to the initial point' 0_iAt this time, the grinding wheel should be simultaneously swung to the position "i", the swinging motion of the grinding wheel is divided into axes A1, Y1 and Z1 of the machine tool according to the motion division principle, and the strokes of the axes A1, Y1 and Z1 are respectively recorded as delta a_i、Δy_i、Δz_iThe relationship between the three and the B1 shaft stroke is as follows:

Δa_i＝Δb_i/z_s

Δy_i＝Etan(Δb_i/z_s)+e(1-1/cos(Δb_i/z_s))

Δz_i＝-etan(Δb_i/z_s)-E(1-1/cos(Δb_i/z_s))

in the formula,. DELTA.b_iIs B1 shaft travel, z_sIs the number of teeth of the pinion cutter corresponding to the drum-shaped worm grinding wheel, E is the axial distance between the worm grinding wheel and the corresponding pinion cutter, and E is the rotation center O of the shaft A1_AAnd the center O of the roller_sOffset in the horizontal direction.

Technical Field

The face gear pair has the advantages of large transmission ratio, high contact ratio, compact structure, insensitivity to installation error and the like, and is mainly applied to the helicopter speed reducer. As one of the core parts of a helicopter power transmission device, a face gear has to keep excellent performance under the working conditions of high speed and heavy load, and the requirement on the accuracy of the face gear tooth surface is greatly improved.

The grinding process is the main means for improving the gear tooth surface precision. A face gear worm grinding wheel grinding machine tool is designed for a face gear worm grinding wheel grinding process, LITVIN and the like, and a face gear worm grinding wheel forming finishing and plane finishing method is provided based on the profile characteristics of the worm grinding wheel. Two face gear worm grinding wheel finishing methods are provided based on single-parameter envelope and double-parameter envelope of Nanjing aerospace university such as Roc, and a special finishing mechanism for the face gear worm grinding wheel is designed. Guohui et al, northwest university of industry, proposed a method for dressing a face gear worm grinding wheel on a numerical control cylindrical gear grinding machine with a forming diamond roller and a standard conical roller, respectively, but the problems of low dressing accuracy and dressing efficiency exist. Therefore, the dressing of the face gear worm grinding wheel is mostly required to be carried out on special equipment, the universality is lacked, and in addition, the dressing precision and the dressing efficiency are still required to be improved. Therefore, the development of the face gear grinding technology for carrying out high-precision and high-efficiency dressing on the face gear worm grinding wheel on the common worm grinding wheel gear grinding machine has great significance.

Disclosure of Invention

Aiming at the defects of the existing method, the invention provides a method for shaping and finishing a drum-shaped worm grinding wheel for grinding a face gear. The eccentric swing of the grinding wheel is used as the trimming stroke motion, the deflection motion of the grinding wheel is decomposed based on the virtual center distance processing principle, and the trimming of the helicoid of the drum-shaped worm grinding wheel is realized in a four-axis linkage mode. The drum-shaped worm grinding wheel for grinding the face gear by utilizing the method does not need to design a special machine tool or a special finishing mechanism, and has higher finishing efficiency and precision.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for shaping and trimming the drum-shaped worm grinding wheel for grinding face gear features that on ordinary worm grinding wheel, the diamond roller is arranged just above the grinding wheel, so the worm grinding wheel is arranged in the vertical plane and in the direction of O_sThe eccentric swinging is carried out as the center, and the shaping and trimming of the drum-shaped worm grinding wheel are completed through the relative arc swinging between the drum-shaped worm grinding wheel and the shaping diamond roller.

As a preferable scheme of the invention, based on the virtual center distance processing principle, the eccentric swing of the worm grinding wheel on a vertical plane is divided into two movements, namely, the grinding wheel rotates around the center O of the axis A1_AThe second is the translation of the grinding wheel on the Y-Z plane.

In a preferred embodiment of the present invention, the rotation of the grinding wheel is effected by a grinding wheel rotation axis B1, the grinding wheel being rotated about O_AThe rotation of the grinding wheel is realized by a tool rest rotating shaft A1, the translation of the grinding wheel on a Y-Z plane is realized by a tangential feed shaft Y1 and an axial feed shaft Z1 together, four-axis linkage of B1, A1, Y1 and Z1 is controlled, the grinding wheel rotates at a constant speed and eccentrically swings relative to a roller, and thus the spiral surface of the drum-shaped worm grinding wheel is trimmed.

As a preferred aspect of the present invention, in order to achieve the purpose of dressing a grinding wheel on a normal cross section, when dressing a drum-shaped worm grinding wheel, a forming diamond roller swings around a C2 axis by an angle λ around the vertical direction, where λ is a nominal helix angle of the drum-shaped worm grinding wheel, and the calculation formula is as follows:

in the formula, n_wThe number of the worm heads, r is the reference circle radius of the pinion cutter corresponding to the drum worm grinding wheel, and z_sThe number of teeth of the gear shaping cutter corresponding to the drum-shaped worm grinding wheel is shown, and E is the axial distance between the worm grinding wheel and the corresponding gear shaping cutter.

In a preferable scheme of the invention, in the linkage process, a stroke relation calculation method of B1, A1, Y1 and Z1 shafts comprises the following steps: selecting stroke to calculate initial point, marking the initial point as '0', wherein the grinding wheel tool rest is horizontal at the initial point, and the center O of the grinding wheel is horizontal_wAnd the center O of the roller_dIn the vertical direction, the grinding wheel and the roller are in the correct mounting position, so that the B1 shaft drives the worm grinding wheel to rotate by any angle delta B relative to the initial point' 0_iAt which time the grinding wheel should be simultaneously deflected into position"i" divides the yawing motion of the grinding wheel into axes A1, Y1 and Z1 of the machine tool according to the motion division principle, and the strokes of the axes A1, Y1 and Z1 are respectively recorded as delta a_i、Δy_i、Δz_iThe relationship between the three and the B1 shaft stroke is as follows:

Δa_i＝Δb_i/z_s

Δy_i＝E tan(Δb_i/z_s)+e(1-1/cos(Δb_i/z_s))

Δz_i＝-e tan(Δb_i/z_s)-E(1-1/cos(Δb_i/z_s))

in the formula,. DELTA.b_iIs B1 shaft travel, z_sIs the number of teeth of the pinion cutter corresponding to the drum-shaped worm grinding wheel, E is the axial distance between the worm grinding wheel and the corresponding pinion cutter, and E is the rotation center O of the shaft A1_AAnd the center O of the roller_sOffset in the horizontal direction.

The invention has the beneficial effects that: the invention realizes the bilateral shaping and trimming of the drum-shaped worm grinding wheel for grinding the face gear by using the shaping diamond roller on the common worm grinding wheel gear grinding machine, and has higher trimming precision and efficiency; the finishing movement of the drum-shaped worm grinding wheel related by the invention can be realized by four-axis linkage of a common worm grinding wheel gear grinding machine, so that the grinding of the face gear is separated from the limit of a special machine tool, and the universality of the gear grinding machine is improved.

Drawings

FIG. 1 is a schematic structural view of a common worm grinding wheel gear grinding machine;

FIG. 2 is a schematic diagram of the forming and dressing of a drum worm grinding wheel;

FIG. 3 is a schematic diagram of a virtual center distance drum worm grinding wheel dressing method;

FIG. 4 is a schematic diagram of the motion of the grinding wheel during dressing.

Detailed Description

The invention is described in further detail below with reference to the figures and the detailed description.

A method for shaping and dressing the drum-shaped worm grinding wheel used for grinding face gear features that the shaping diamond roller is used, and the drum-shaped worm grinding wheel is dressed by ordinary worm grinding wheel gear grinding machine in four-axle linkage mode.

The structure of a common worm grinding wheel gear grinding machine is shown in figure 1, main motion axes comprise an X1 radial feed axis, a Y1 tangential feed axis, a Z1 axial feed axis, an A1 tool rest rotating shaft, a B1 grinding wheel rotating shaft and a C1 workpiece rotating shaft, and six-axis linkage of X1, Y1, Z1, A1, B1 and C1 can be realized. In addition, there is a B2 roller pivot shaft and a C2 roller yaw shaft. On a common worm grinding wheel gear grinding machine, the axis of a grinding wheel can rotate around the center of an A1 shaft and is always parallel to a Y-Z surface; the axis of the diamond roller can deflect around the axis C2 and is always parallel to the X-Y plane, but the deflection angle is very limited.

The worm wheel design parameters in the following table are given as examples.

The normal section profile of the drum-shaped worm grinding wheel is as shown in fig. 2, the normal section profile is the same as the profile of the corresponding gear shaper cutter, and different from the common cylindrical worm grinding wheel, the outer edge profile of the drum-shaped worm grinding wheel is a circular arc instead of a straight line. When the drum-shaped worm grinding wheel is shaped and dressed, a shaped diamond roller with the same section profile as the tooth space profile of the gear shaper cutter is adopted and is arranged on the normal section of the worm grinding wheel, the diamond roller performs arc deflection motion relative to the grinding wheel in the axial direction of the grinding wheel as dressing stroke motion, and the deflection center O is used_sAnd the center O of the grinding wheel_wAre not coincident.

According to the profile characteristics of the drum-shaped worm grinding wheel and the structural characteristics of the gear grinding machine, in order to finish the drum-shaped worm grinding wheel on a common worm grinding wheel gear grinding machine, a forming diamond roller needs to be arranged right above the worm grinding wheel, and as shown in fig. 3, the roller and the grinding wheel need to respectively complete the following motions:

for the diamond roller, the diamond roller is rotated around the axis thereof at high speed through a B2 shaft and is rotated at an angle in a vertical plane through a C2 shaftTo achieve trimming on normal sectionThe purpose of the worm grinding wheel.

The worm grinding wheel rotates around the axis of the worm grinding wheel at a constant speed through the B1 shaft, and simultaneously, the grinding wheel eccentrically swings relative to the roller through the linkage of the A1, the Y1, the Z1 shaft and the B1 shaft. The eccentric oscillation of the grinding wheel can be decomposed into a rotation about O effected by the axis A1_AAnd the translation in the Y-Z plane is realized by the axes Y1 and Z1. And controlling four-axis linkage of B1, A1, Y1 and Z1 to enable the grinding wheel to eccentrically swing relative to the roller while rotating at a constant speed so as to finish the spiral surface of the drum worm.

During the linkage process, the stroke relation of the axes B1, A1, Y1 and Z1 can be calculated according to the motion diagram of FIG. 4, the position shown in FIG. 4a) is the initial point of stroke calculation, the initial point is marked as '0', the grinding wheel tool rest is horizontal at the initial point, and the grinding wheel center O is horizontal_wAnd the center O of the roller_dIn the vertical direction, the grinding wheel and the roller are in the correct mounting position, and when the B1 shaft drives the worm grinding wheel to rotate by any angle delta B relative to the initial point' 0_iWhen the grinding wheel should simultaneously deflect to the position "i", the deflection motion of the grinding wheel is decomposed to the axes A1, Y1 and Z1 according to the motion decomposition principle, as shown in FIG. 4b), and the strokes of the axes A1, Y1 and Z1 are respectively recorded as delta a_i、Δy_i、Δz_iThe relationship between the three and the B1 shaft stroke is as follows:

Δa_i＝Δb_i/z_s

Δy_i＝E tan(Δb_i/z_s)+e(1-1/cos(Δb_i/z_s))

Δz_i＝-e tan(Δb_i/z_s)-E(1-1/cos(Δb_i/z_s))

in the formula,. DELTA.b_iIs B1 shaft travel, z_sIs the number of teeth of the pinion cutter corresponding to the drum-shaped worm grinding wheel, E is the axial distance between the worm grinding wheel and the corresponding pinion cutter, and E is the rotation center O of the shaft A1_AAnd the center O of the roller_sOffset in the horizontal direction.

On a common worm grinding wheel gear grinding machine, four shafts B1, A1, Y1 and Z1 are controlled by a numerical control system to be linked, so that relative swinging between a diamond roller and a worm grinding wheel is completed, and the dressing of the helicoid of the drum-shaped worm grinding wheel is realized.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.