Herringbone gear centering precision detection method

Abstract

The invention relates to the technical field of herringbone gear centering errors, in particular to a herringbone gear centering precision detection method which comprises the steps that the middle plane of a herringbone gear to be detected is determined, a coordinate system is established, the original point of the coordinate system is the intersection point of a reference axis and the middle plane, the Z axis coincides with the reference axis, and the Y axis and the X axis are located in the middle plane. The X axis, the Y axis and the Z axis are perpendicular to one another; the method comprises the following steps: respectively selecting two tooth sockets from a left-hand tooth socket and a right-hand tooth socket which are symmetrical to each other of a herringbone gear to be measured for measurement, constructing four virtual balls tangent to the tooth surfaces of the measured tooth sockets in a coordinate system through three-coordinate measurement software, and connecting the centers of the virtual balls in the tooth sockets on the same side to intersect with a middle plane to obtain two intersection points; the difference delta X of the coordinate values of the two points in the X direction is solved, the centering error of the herringbone gear can be solved through the formula delta Z = delta X / 2tan beta, and beta is the tooth direction helical angle of the herringbone gear to be measured. According to the detection method, the measurement point can be accurately obtained, and the measurement precision is high.

Description

Technical Field

[0001] The invention relates to the technical field of herringbone gear centering detection, and in particular to a herringbone gear centering accuracy detection method. Background Art

[0002] The herringbone gear transmission has the advantages of high load-bearing capacity and good working stability, and is adopted in the traction transmission system of 400KM high-speed railway locomotives.

[0003] High-precision herringbone gears have strict requirements for the centering error of the intersection of the symmetry lines of the tooth grooves of the herringbone gears. Before this, there was no such detection technology, and the error could not be accurately detected, making it difficult to judge the centering error of the symmetry lines of the tooth grooves of the herringbone gears. At present, there are three main methods for processing herringbone gears: the first is to use a four-axis or five-axis machining center to complete the milling of the herringbone gears in one clamping. This method is mainly used on herringbone gears with narrow undercuts that cannot be hobbed. The second method is to use a hobbing machine with an undercut, first process one rotation direction, and then process the other rotation direction by marking and positioning; the third method is to process the two gears separately without an undercut, and then assemble the two gears into a herringbone gear by aligning the tooling. In the first processing method, the centering error of the herringbone gear tooth groove is mainly affected by the accuracy of the four-axis or five-axis machining center, milling cutter wear, tooling accuracy, herringbone gear reference accuracy, operator alignment accuracy and processing program accuracy, making it difficult to control the centering error of the symmetry line of the herringbone gear tooth groove; in the second processing method of herringbone gear, the centering error of the herringbone gear tooth groove is mainly controlled by marking and tool setting. Since the errors of marking and gear hobbing are relatively large, and the errors of tooth surface carburizing and quenching, positioning reference surface finishing and gear grinding are superimposed after the herringbone gear is opened, the centering error of the herringbone gear tooth groove is difficult to control; in the third processing method of herringbone gear, the centering error of the herringbone gear tooth groove needs to be tested to ensure that the centering error of the combined herringbone gear tooth groove meets the requirements. Fine milling or grinding is the last processing step of herringbone gear processing, with relatively small allowance. If the centering error of the tooth groove symmetry line is large during the rough opening of the herringbone gear, fine milling or grinding cannot fully process the surface within the range of the cross-ball distance or the common normal line size, and black skin will remain on the surface, affecting the use. Therefore, the centering error of the tooth groove symmetry line of the herringbone gear needs to be measured after the rough opening of the herringbone gear to ensure that the effective tooth surface can be fully processed during the fine milling or grinding of the herringbone gear; at the same time, whether the centering error of the herringbone tooth groove symmetry line after fine milling or grinding meets the requirements of the drawing, it is also necessary to measure the centering error of the herringbone tooth groove symmetry line, otherwise it will affect the use of the herringbone gear.

[0004] In the prior art, the patent application number is 201010261231.X, and the patent name is a method for detecting the centering error of herringbone gears. By measuring the centering error ΔX of the herringbone tooth line in the tangent direction, and then indirectly obtaining the centering error ΔZ through a formula, the centering error ΔZ that is difficult to measure is avoided, and the effective measurement of the centering error is achieved. The key to this method is to take two points on the tooth surface of the herringbone gear as measuring points, but the tooth surface machining accuracy of the herringbone gear is low after the rough opening of the tooth. When measuring with a three-coordinate measuring machine, the measuring points cannot be accurately obtained, and the theoretical value of the measuring point is prone to error. After calculation by the calculation formula, it will cause the cumulative error of the symmetry to be magnified several times. Therefore, this method is not suitable for the symmetry detection of herringbone gears after grinding. Therefore, a method for detecting the centering accuracy of herringbone gears is urgently needed to solve the problem of high measurement difficulty and low measurement accuracy when measuring the centering error of the herringbone gear tooth groove symmetry line after the rough opening of the herringbone gear in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a method for detecting the centering accuracy of herringbone gears to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for detecting the centering accuracy of a herringbone gear, which detects the centering accuracy of the herringbone gear to be tested by a three-coordinate testing machine, comprising the following detection steps: S1. Determine the middle plane of the herringbone gear to be tested. The middle plane is a plane perpendicular to the reference axis of the herringbone gear and parallel to and equidistant from the reference end faces on both sides of the herringbone gear to be tested. S2. Establish a coordinate system, the origin of which is the intersection of the reference axis and the middle plane, the Z axis coincides with the reference axis, the Y axis and the X axis are in the middle plane, and the X axis, the Y axis and the Z axis are perpendicular to each other; S3, selecting a number of measuring positions in a symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear to be tested, and scanning and measuring the tooth grooves where the selected measuring positions are located by a three-coordinate measuring machine; S4. After completing the scanning measurement of the tooth groove at the measuring position, construct several virtual spheres tangent to the tooth surface of the measured tooth groove in the coordinate system through the three-coordinate measurement software, connect the centers of the virtual spheres in the tooth groove on the same side and intersect with the middle plane to obtain two intersection points, and calculate the difference ΔX between the coordinate values ​​of the two points in the X direction. The centering error of the herringbone gear can be calculated through the formula ΔZ=ΔX / 2tanβ, where β is the tooth helix angle of the herringbone gear to be measured.

[0007] Preferably, in S3, two measuring positions are selected in each of a symmetrical left-handed and right-handed tooth groove of the herringbone gear to be measured.

[0008] Preferably, the virtual ball is a measuring ball for measuring the gear cross-ball distance.

[0009] Preferably, the calculation formula of the diameter d of the measuring ball is d = dj × [tan (α min + 90° / Z) - tan (α min)], wherein dj is the tooth base circle diameter of the herringbone gear to be measured, and α min is the tooth base circle end face pressure angle of the herringbone gear to be measured.

[0010] Preferably, in S3, when two measuring positions are selected in each of a symmetrical left-handed and right-handed tooth groove of the herringbone gear to be measured, the two measuring positions in the left-handed tooth groove and the two measuring positions in the right-handed tooth groove are symmetrically arranged one by one.

[0011] Preferably, in S3, the two measuring positions in the left-handed tooth groove are: the tooth groove at a distance of 1 / 4 of the length of the tooth width of the left-handed gear and 3 / 4 of the length of the tooth width of the left-handed gear from the reference end face on the left-handed gear side; the two measuring positions in the right-handed tooth groove are: the tooth groove at a distance of 1 / 4 of the length of the tooth width of the right-handed gear and 3 / 4 of the length of the tooth width of the right-handed gear from the reference end face on the right-handed gear side.

[0012] Preferably, in S3, when the tooth grooves at the selected measurement positions are scanned and measured by a three-coordinate measuring machine, the three-coordinate measuring machine is perpendicular to the spiral direction of the left-handed gear or right-handed gear to be measured, and scans the tooth groove from the tooth top to the tooth root and then to the tooth top.

[0013] Preferably, in S4, when a virtual sphere tangent to the tooth surface of the tooth groove to be measured is constructed in the coordinate system by three-coordinate measurement software, a reference plane where the measurement position is located is first constructed in the coordinate system, and then a point is selected on the reference plane as the center of the sphere, and then a hollow sphere is constructed with the center of the sphere, and the hollow sphere is tangent to the tooth surfaces on both sides of the tooth groove where the measurement position is located, thereby constructing a virtual sphere.

[0014] Preferably, the reference surface is parallel to the reference end surfaces on both sides of the herringbone gear to be tested.

[0015] Preferably, a symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear to be tested are any symmetrical left-handed tooth groove and right-handed tooth groove in the herringbone gear to be tested.

[0016] Beneficial effect: When the present invention measures the herringbone gear to be measured by a three-coordinate detection machine, the middle plane is determined and a coordinate system is established on the middle plane, and then two measurement positions in a symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear are measured. Four virtual spheres tangent to the scanned involute tooth groove tooth surface are constructed by three-coordinate measurement software, and the centers of the virtual spheres on the gears on the same side are connected to intersect with the middle plane to obtain two intersection points, and the difference ΔX between the coordinate values ​​of the two points in the X direction is calculated. The centering error of the herringbone gear can be calculated by the formula ΔZ=ΔX / 2tanβ. The detection method of the present invention is to measure the tooth groove of the herringbone gear and use the measurement software to construct a virtual sphere tangent to the measured tooth groove in the coordinate system, and then use the line connecting the centers of the spheres and the middle plane to obtain two intersection points, and then use the formula to calculate the centering error of the herringbone gear. The detection method of the present invention can accurately obtain the measuring point and will not be affected by the low tooth surface machining accuracy after the herringbone gear is roughly opened. In addition, the error deviation of the theoretical value of the measuring point where the center of the ball is located can be reduced by measuring the virtual ball of the tooth groove structure, thereby ensuring the accuracy of the final centering. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of a herringbone gear to be tested in an embodiment; Figure 2 It is a schematic structural diagram of the measuring ball of the embodiment. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0019] Example: Figure 1-Figure 2 As shown: This embodiment provides a method for detecting the centering accuracy of a herringbone gear, which detects the centering accuracy of the herringbone gear to be tested by a three-coordinate testing machine, including the following detection steps: S1. Import the three-dimensional model of the herringbone gear to be tested into the three-dimensional coordinate testing machine, such as Figure 1 As shown, the two sides of the herringbone gear are driving shafts, and the outer side of the driving shaft is the outer cylindrical surface 1 and 9, and the middle plane 5 of the herringbone gear to be tested is determined. The middle plane is a plane that is perpendicular to the reference axis of the herringbone gear, that is, the axis of the herringbone gear, and is parallel to and equidistant from the reference end faces on both sides of the herringbone gear to be tested; wherein the reference end faces on both sides of the herringbone gear to be tested are defined as the upper reference end face 2 and the lower reference end face 8; S2. Establish a coordinate system, the origin of which is the intersection of the reference axis and the middle plane 5, the Z axis of the coordinate system coincides with the reference axis, the Y axis and the X axis are in the middle plane 5, and the X axis, the Y axis and the Z axis are perpendicular to each other; S3, select two measuring positions in each of a symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear to be tested, and scan and measure the tooth grooves where the selected measuring positions are located by a three-coordinate measuring machine; wherein, when selecting the measuring positions, the two measuring positions in the left-handed tooth groove and the two measuring positions in the right-handed tooth groove are symmetrically arranged one by one; specifically, in a pair of left-handed tooth grooves and right-handed tooth grooves selected for the herringbone gear to be tested in this embodiment, the two measuring positions in the left-handed tooth groove are respectively: the tooth groove at a distance from the reference end face of the left-handed gear side by 1 / 4 of the length of the tooth width of the left-handed gear and 3 / 4 of the length of the tooth width of the left-handed gear; the two measuring positions in the right-handed tooth groove are respectively: the tooth groove at a distance from the reference end face of the right-handed gear side by 1 / 4 of the length of the tooth width of the right-handed gear and 3 / 4 of the length of the tooth width of the right-handed gear, and a total of four tooth grooves are measured; S4. After completing the scanning measurement of the tooth grooves at the measuring position, the three-coordinate measurement software is used to construct reference planes parallel to the reference end faces on both sides of the herringbone gear to be measured at the positions of the four tooth grooves in the coordinate system, which are left-handed tooth groove reference plane 3 and reference plane 4, and right-handed tooth groove reference plane 6 and reference plane 7. Then, a point is selected from the four constructed reference planes as the center of the sphere, and a hollow sphere is formed with the center of the sphere. The hollow sphere is tangent to the involute tooth groove tooth surface at the measuring position, that is, four virtual spheres are constructed. Then, the centers of the virtual spheres in the tooth grooves on the same side are connected and extended toward the middle plane to form two connecting extension lines. The two connecting extension lines will intersect with the middle plane 5 to obtain two intersection points or intersect to obtain an intersection point H. At this time, it should be noted that if the two connecting extension lines intersect with the middle plane 5 at point H, it indicates that the hedging error of the herringbone gear to be measured is zero, and the middle plane 5 is the plane where the symmetry line of the herringbone gear tooth groove is located. If the two connecting extension lines intersect the middle plane at two points, then find the difference ΔX between the coordinate values ​​of the two points in the X direction. The centering error of the herringbone gear can be found by the formula ΔZ=ΔX / 2tanβ, where β is the tooth helix angle of the herringbone gear to be tested. After finding the centering error of the herringbone gear, the deviation direction of the centering error can be determined according to the actual value of the left and right helical tooth groove detection point of the herringbone gear, so as to change the position of the tooth groove symmetry plane by milling or grinding the tooth surface of the herringbone gear, and finally meet the centering requirements of the herringbone gear tooth line.

[0020] The virtual ball of this embodiment is a measuring ball for measuring the gear span. The calculation formula of the diameter d of the measuring ball is d = dj × [tan (α min + 90° / Z) - tan (α min)], where dj is the tooth base circle diameter of the herringbone gear to be measured, and α min is the tooth base circle end face pressure angle of the herringbone gear to be measured.

[0021] In S3 of this embodiment, when the tooth grooves at the selected measurement positions are scanned and measured by the three-coordinate measuring machine, the three-coordinate measuring machine is perpendicular to the spiral line direction of the left-handed gear or the right-handed gear to be measured, and scans the tooth groove from the tooth top to the tooth root and then to the tooth top.

[0022] In this embodiment, a symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear to be tested are any symmetrical left-handed tooth groove and right-handed tooth groove in the herringbone gear to be tested.

[0023] In summary, the embodiment of the present invention determines the middle plane and establishes a coordinate system on the middle plane, then measures a pair of symmetrical tooth grooves of the left and right herringbone gears, and uses a three-dimensional coordinate measuring machine to scan the tooth grooves at 1 / 4 and 3 / 4 of the tooth width of the upper and lower gears from the tooth top to the tooth root and then to the tooth top perpendicular to the spiral line direction. Four virtual spheres tangent to the scanned involute tooth groove tooth surface are constructed by three-dimensional coordinate measurement software, and the centers of the virtual circles on the gears on the same side are connected to intersect with plane 5 to obtain two intersection points, and the difference ΔX between the coordinate values ​​of the two points in the X direction is calculated. The axial centering error of the herringbone gear can be calculated by the formula ΔZ=ΔX / 2tanβ, thereby achieving effective measurement of the centering error.

[0024] As above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A method for detecting the centering accuracy of a herringbone gear, which uses a three-coordinate measuring machine to detect the centering accuracy of the herringbone gear to be measured, and is characterized by: The following detection steps are included: S1. Determine the middle plane of the herringbone gear to be tested, wherein the middle plane is a plane perpendicular to the reference axis of the herringbone gear and parallel to and equidistant from the reference end faces on both sides of the herringbone gear to be tested; S2. Establish a coordinate system, the origin of which is the intersection of the reference axis and the middle plane, the Z axis coincides with the reference axis, the Y axis and the X axis are in the middle plane, and the X axis, the Y axis and the Z axis are perpendicular to each other; S3, selecting a number of measuring positions in a symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear to be tested, and scanning and measuring the tooth grooves where the selected measuring positions are located by a three-coordinate measuring machine; S4. After completing the scanning measurement of the tooth groove at the measuring position, construct several virtual spheres tangent to the tooth surface of the measured tooth groove in the coordinate system through the three-coordinate measurement software, connect the centers of the virtual spheres in the tooth groove on the same side and intersect with the middle plane to obtain two intersection points, and calculate the difference ΔX between the coordinate values ​​of the two points in the X direction. The centering error of the herringbone gear can be calculated through the formula ΔZ=ΔX / 2tanβ, where β is the tooth helix angle of the herringbone gear to be measured.

2. The method for detecting the centering accuracy of herringbone gears according to claim 1, characterized in that: In S3, two measuring positions are selected in each of a symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear to be measured.

3. The method for detecting the centering accuracy of herringbone gears according to claim 1, characterized in that: The virtual ball is a measuring ball for measuring the gear span distance.

4. The method for detecting the centering accuracy of herringbone gears according to claim 3, characterized in that: The calculation formula of the diameter d of the measuring ball is d = dj × [tan (α min + 90° / Z) - tan (α min)], wherein dj is the tooth base circle diameter of the herringbone gear to be measured, and α min is the tooth base circle end face pressure angle of the herringbone gear to be measured.

5. The method for detecting the centering accuracy of herringbone gears according to claim 2, characterized in that: In S3, when two measuring positions are selected in each of a symmetrical left-handed and right-handed tooth groove of the herringbone gear to be measured, the two measuring positions in the left-handed tooth groove and the two measuring positions in the right-handed tooth groove are symmetrically arranged one by one.

6. The method for detecting the centering accuracy of herringbone gears according to claim 5, characterized in that: In S3, the two measuring positions in the left-handed tooth groove are: the tooth groove at a distance of 1 / 4 of the tooth width of the left-handed gear and 3 / 4 of the tooth width of the left-handed gear from the reference end face on the left-handed gear side; the two measuring positions in the right-handed tooth groove are: the tooth groove at a distance of 1 / 4 of the tooth width of the right-handed gear and 3 / 4 of the tooth width of the right-handed gear from the reference end face on the right-handed gear side.

7. The method for detecting the centering accuracy of herringbone gears according to claim 1, characterized in that: In S3, when the tooth grooves at the selected measuring positions are scanned and measured by a three-coordinate measuring machine, the three-coordinate measuring machine is perpendicular to the spiral line direction of the left-handed gear or right-handed gear to be measured, and scans the tooth groove from the tooth top to the tooth root and then to the tooth top.

8. The method for detecting the centering accuracy of herringbone gears according to claim 1, characterized in that: In S4, when a virtual sphere tangent to the tooth surface of the tooth groove to be measured is constructed in the coordinate system by three-coordinate measurement software, a reference plane where the measurement position is located is first constructed in the coordinate system, and then a point is selected on the reference plane as the center of the sphere, and then a hollow sphere is constructed with the center of the sphere. The hollow sphere is tangent to the tooth surfaces on both sides of the tooth groove where the measurement position is located, and thus the virtual sphere is constructed.

9. The method for detecting the centering accuracy of herringbone gears according to claim 8, characterized in that: The reference surface is parallel to the reference end surfaces on both sides of the herringbone gear to be tested.

10. The method for detecting the centering accuracy of herringbone gears according to claim 1, characterized in that: A symmetrical left-handed tooth groove and a right-handed tooth groove of the herringbone gear to be tested are any symmetrical left-handed tooth groove and right-handed tooth groove in the herringbone gear to be tested.

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