A method for detecting the side clearance control size of a rigid pulley for harmonic transmission

Abstract

The present invention discloses a detection method for the side clearance control size of a rigid wheel for harmonic transmission, which adopts two or three measuring blocks in conjunction with a two-claw or three-claw internal diameter micrometer for detection; during measurement, a measuring block is respectively pasted at the interval of 180° or 120° between the internal teeth of the rigid wheel, and then the outer edge of the two-claw or three-claw internal diameter micrometer probe contacts the inner wall of the measuring block to measure the control size H of the rigid wheel when the harmonic gear meshes with the side clearance. In the present invention, since the width of the measuring block is much larger than the tooth pitch of the harmonic gear, it is not necessary to strictly maintain the equal spacing of 180° or 120° when placing the measuring block, as long as the measuring contact of the internal diameter micrometer can contact the inner wall of the measuring block; any position can be measured without being restricted by the tooth groove or tooth top of the rigid wheel; comprehensive detection of the tooth surface of the rigid wheel and the flexible wheel can be realized to avoid the error caused by single section detection; the spatial position occupied by the flexible wheel during actual assembly is simulated, and the control result is more accurate and effective.

Description

Technical Field

[0001] The invention relates to a method for detecting a side clearance control dimension of a rigid wheel for harmonic transmission, and belongs to the technical field of mechanical transmission detection. Background Art

[0002] The harmonic drive is mainly composed of a rigid wheel, a flexwheel and a wave generator. The inner circle of the rigid wheel is provided with internal teeth, the outer circle of the flexwheel is provided with external teeth, and the flexwheel is sleeved on the elliptical wave generator. Under the action of the wave generator, the flexwheel undergoes controllable deformation, so that the external teeth of the flexwheel near the long axis of the wave generator are completely meshed with the internal teeth of the rigid wheel; the external teeth of the flexwheel near the short axis of the wave generator are completely disengaged from the internal teeth of the rigid wheel; the external teeth of the flexwheel between the long axis and the short axis gradually disengage or mesh with the internal teeth of the rigid wheel.

[0003] The transmission meshing backlash between the external teeth of the flexspline and the internal teeth of the rigid wheel determines the performance of the harmonic gear transmission. If the meshing backlash is too large, the transmission backlash error will be the largest, and even affect the correct conjugate meshing of the gear teeth; if the meshing backlash is too small, meshing interference may occur, operation heat, tooth surface wear, and premature failure. When the deformation of the wave generator is constant, the tooth thickness of the external teeth of the flexspline and the internal teeth of the rigid wheel directly determines the meshing backlash of the harmonic drive.

[0004] Since harmonic gears are small-module gears, the existing technology for detecting the tooth thickness of flexible splines and rigid splines uses the method of measuring the span-rod distance. Flexible splines are external gears, and the span-rod distance size can be easily and accurately measured. However, rigid splines are internal gears, and it is difficult to align the extreme positions of the two measuring rods during measurement, so the measurement accuracy is not high. In addition, the span-rod distance measurement method only reflects the size of a specific cross-section, and cannot comprehensively reflect the processing errors and tooth surface roughness effects caused by factors such as tools. Usually, during assembly, it is also necessary to group the assembly according to the tightness of the assembly, which makes the production efficiency of harmonic gears low and the quality fluctuation range wide. Therefore, the existing technology still has shortcomings and needs to be further improved. Summary of the invention

[0005] The object of the present invention is to provide a method for detecting the control size of a rigid wheel for harmonic transmission which is easy to operate and accurate in measurement, so as to indirectly control the meshing side clearance under the assembly condition of the rigid wheel and the flexible wheel, thereby overcoming the shortcomings of the prior art.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention discloses a method for detecting the controlled dimension of a rigid wheel when the harmonic gear has a reasonable meshing backlash. The method adopts two or three measuring blocks and cooperates with a two-jaw or three-jaw internal diameter micrometer for detection. During the measurement, a measuring block is respectively pasted at a 180° or 120° interval between the internal teeth of the rigid wheel, and then the outer edge of the two-jaw or three-jaw internal diameter micrometer probe contacts the inner wall of the measuring block to measure the controlled dimension H of the rigid wheel when the harmonic gear has a reasonable meshing backlash.

[0008] In the above detection method, when the measured rigid wheel backlash control size H = wave generator long axis size L, it means that the rigid wheel and the flexible wheel can just maintain backlash-free meshing; when the measured rigid wheel backlash control size H> wave generator long axis size L, it means that there is a backlash δ between the rigid wheel and the flexible wheel;

[0009] δ=△H×tgβ;

[0010] Where: △H represents the correction amount △H of the inner wall dimension H of the measuring block to ensure reasonable meshing side clearance; β represents the tooth angle of the rigid wheel.

[0011] In the above detection method, the measuring block is a partial sector gear cut from the flexible spline; the number of measuring blocks corresponds to the number of claws of the internal diameter micrometer.

[0012] In the above detection method, the width of the measuring block is an arc length of 5 to 10 mm in the direction of the circumference of the inner hole of the flexible wheel.

[0013] Due to the adoption of the above technical scheme, compared with the prior art, the present invention has the following advantages: since the width of the measuring block is much larger than the tooth pitch of the harmonic gear, it is not necessary to strictly maintain an equal spacing of 180° or 120° when placing the measuring block, as long as the measuring contacts of the inside micrometer can contact the inner wall of the measuring block (it can be misaligned); any position can be measured without being restricted by the tooth grooves or tooth tops of the rigid wheel; comprehensive detection of the tooth surfaces of the rigid wheel and the flexspline can be achieved, avoiding the error caused by single cross-section detection; simulating the spatial position occupied by the flexspline during actual assembly, the control result is more accurate and effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the meshing principle and backlash of harmonic gears;

[0015] Figure 2 This is a schematic diagram of the present invention using a two-claw internal diameter micrometer for detection;

[0016] Figure 3 This is a schematic diagram of the present invention using a three-jaw internal diameter micrometer for detection;

[0017] Figure 4 It is a schematic diagram of the structure of the measurement block of the present invention;

[0018] Figure 5This is a partial enlarged view of the measurement block and the rigid wheel meshing without backlash at the long axis of the wave generator.

[0019] The marks in the accompanying drawings are: 1-rigid wheel, 2-flexible wheel, 3-wave generator, 4-wave generator long axis, 5-flexible wheel external teeth, 6-rigid wheel internal teeth, 7-wave generator short axis, 8-meshing side clearance, 9-measuring block, 10-inside diameter micrometer probe. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0021] The present invention provides a method for detecting the controlled dimension of a rigid wheel for harmonic transmission. The method uses two or three measuring blocks 9 in conjunction with a two-jaw or three-jaw internal diameter micrometer for detection. During measurement, a measuring block 9 is respectively pasted at intervals of 180° or 120° on the internal teeth 6 of the rigid wheel, and then the outer edge of the two-jaw or three-jaw internal diameter micrometer probe 10 contacts the inner wall of the measuring block to measure the controlled dimension H of the rigid wheel when the harmonic gear has a reasonable meshing side clearance.

[0022] When the measured rigid wheel backlash control dimension H is equal to the wave generator long axis dimension L, it means that the rigid wheel and the flexible wheel can just maintain backlash-free meshing; when the measured rigid wheel backlash control dimension H is greater than the wave generator long axis dimension L, it means that there is a backlash δ between the rigid wheel and the flexible wheel;

[0023] δ=△H×tgβ;

[0024] Where: △H represents the correction amount △H of the inner wall dimension H of the measuring block to ensure reasonable meshing side clearance; β represents the tooth angle of the rigid wheel.

[0025] The measuring block 9 is a partial sector gear cut from the flexible wheel 2. The number of measuring blocks 9 corresponds to the number of claws of the internal diameter micrometer. The width of the measuring block 9 is an arc length of 5 to 10 mm in the direction of the circumference of the inner hole of the flexible wheel 2. Example

[0026] The detection object in this example is Figure 1 The harmonic gear transmission mechanism shown in the figure is mainly composed of a rigid wheel 1, a flexible wheel 2 and a wave generator 3. The inner circle of the rigid wheel 1 is provided with internal teeth, the outer circle of the flexible wheel 2 is provided with external teeth, and the flexible wheel 2 is sleeved on the elliptical wave generator 3. Under the action of the wave generator 3, the flexible wheel 2 undergoes controllable deformation, so that the flexible wheel external teeth 5 near the long axis 4 of the wave generator are completely meshed with the rigid wheel internal teeth 6; the flexible wheel external teeth 5 near the short axis 7 of the wave generator are completely disengaged from the rigid wheel internal teeth 6; the flexible wheel external teeth 5 between the long axis and the short axis are gradually disengaged from or meshed with the rigid wheel internal teeth 6.

[0027] The transmission meshing clearance between the flex spline external teeth 5 and the rigid wheel internal teeth 6 determines the performance of the harmonic gear transmission. If the meshing clearance is too large, the transmission backlash error is the largest, and even affects the correct conjugate meshing of the gear teeth; if the meshing clearance is too small, meshing interference may occur, operation heat, tooth surface wear, and premature failure. When the deformation of the wave generator 3 is constant, the tooth thickness size of the flex spline external teeth 5 and the rigid wheel internal teeth 6 directly determines the meshing clearance 8 of the harmonic transmission.

[0028] Since harmonic gears are small-module gears, the existing technology for detecting the tooth thickness of flexible splines and rigid splines uses the method of measuring the span-rod distance. Flexible splines are external gears, and the span-rod distance size can be easily and accurately measured. However, rigid splines are internal gears, and it is difficult to align the extreme positions of the two measuring rods during measurement, so the measurement accuracy is not high. In addition, the span-rod distance measurement method only reflects the size of a specific cross-section, and cannot comprehensively reflect the processing errors and tooth surface roughness effects caused by factors such as tools. Usually, during assembly, it is also necessary to group the assembly according to the tightness of the assembly, which makes the production efficiency of harmonic gears low and the quality fluctuation range wide. Therefore, the existing technology still has shortcomings and needs to be further improved.

[0029] The main measuring tools used in this method include a set of measuring blocks 9 and an inside micrometer. The measuring block 9 is a partial sector gear cut from the ring gear of the flexible wheel 2. The width of the measuring block 9 is an arc length of 5 to 10 mm in the direction of the circumference of the inner hole of the flexible wheel 2. The length of the measuring block 9 is determined according to the structure of the rigid wheel 1 and is convenient for operation. It is generally 10 to 20 mm. The inside micrometer is a universal linear dimension measuring tool, which can be three probes or two probes. The number of measuring blocks 9 is configured according to the number of inside micrometer probes 10, and each inside micrometer probe 10 is configured with a measuring block 9.

[0030] The measuring principle of the present invention is as follows Figure 5 shown.

[0031] The principle is to indirectly control the meshing backlash 8 of the rigid wheel 1 and the flexible wheel 2 by controlling the backlash-free double meshing center distance of the gears.

[0032] The radial deformation of the wave generator 3 is very small relative to the diameter of the inner hole of the flexible wheel 2. Therefore, the radius of curvature of the inner hole of the flexible wheel 2 near the long axis 4 of the wave generator after deformation is basically the same as the radius of the flexible wheel 2 without deformation. Therefore, the measuring block 9 in the undeformed state can be used to simulate the position of the flexible wheel near the long axis 4 of the wave generator during actual assembly. The measuring block 9 is placed close to the inner wall of the rigid wheel 1 to be measured, and the measuring block 9 is kept in meshing with the inner teeth 6 of the rigid wheel without side clearance. The inner wall dimension H of the measuring block 9 is detected. When the detected H is equal to the dimension L of the long axis 4 of the wave generator, the rigid wheel 1 and the flexible wheel 2 can just maintain meshing without side clearance. According to the meshing side clearance and tooth profile angle β at the long axis determined by the design, when the reasonable meshing side clearance δ is ensured, the correction amount △H of the inner wall dimension H of the measuring block 9 is measured.

[0033] △H=δ / tgβ

[0034] Where: δ is the reasonable meshing backlash, β is the tooth profile angle, and △H is the correction amount of the inner wall dimension H of the measuring block when the meshing backlash is reasonable.

[0035] When machining the internal teeth 6 of the rigid wheel, as long as the inner wall detection dimension H=L+△H of the measuring block 9 is controlled, it can be ensured that the rigid wheel 1 and the flexible wheel 2 have a reasonable meshing side clearance under the assembly condition.

[0036] Specific implementation method: The detection method of the rigid wheel control size when the harmonic gear has reasonable meshing side clearance of the present invention uses the tooth thickness of the measuring block 9 as the detection reference. Therefore, the premise of using the present invention is that the inner hole, tooth thickness, and tooth profile of the flexible wheel 2 must maintain a high degree of consistency with the measuring block 9.

[0037] When using a two-jaw internal micrometer (i.e., two probes) for measurement, two measuring blocks 9 are pasted at 180° intervals on the inner wall of the rigid wheel 1; when using a three-jaw internal micrometer (i.e., three probes) for measurement, three measuring blocks 9 are pasted at 120° intervals on the inner wall of the rigid wheel 1. During the inspection, keep each internal micrometer probe 10 in contact with the inner wall of the measuring block 9, and the maximum dimension H measured is the control dimension of the rigid wheel when ensuring reasonable meshing side clearance.

Claims

1. A method for detecting the side clearance control size of a rigid wheel for harmonic transmission, characterized in that: The method uses two or three measuring blocks in conjunction with a two-claw or three-claw internal diameter micrometer for detection; the measuring block is a partial sector gear cut from the flexible wheel gear ring; when measuring, a measuring block is respectively pasted at the interval of 180° or 120° between the inner teeth of the rigid wheel, and the measuring block is pressed against the inner wall of the rigid wheel to be measured, so that the measuring block and the inner tooth surface of the rigid wheel are kept in meshing without side clearance, and then the outer edge of the two-claw or three-claw internal diameter micrometer probe contacts the inner wall of the measuring block to measure the side clearance control dimension H of the rigid wheel; when the measured side clearance control dimension H of the rigid wheel is equal to the long axis dimension L of the wave generator, it indicates that the rigid wheel and the flexible wheel can just maintain a side clearance-free meshing; when the measured side clearance control dimension H of the rigid wheel is greater than the long axis dimension L of the wave generator, it indicates that there is a side clearance δ between the rigid wheel and the flexible wheel; δ=△H×tgβ; Where: △H represents the correction amount △H of the inner wall dimension H of the measuring block to ensure reasonable meshing side clearance; β represents the tooth angle of the rigid wheel.

2. The detection method according to claim 1, characterized in that: The measuring blocks are partial sector gears cut from the flexible wheel; the number of measuring blocks corresponds to the number of claws of the internal diameter micrometer.

3. The detection method according to claim 1, characterized in that: The width of the measuring block is 5 to 10 mm in arc length in the direction of the circumference of the inner hole of the flexible wheel.

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