Auxiliary measuring device and measuring method for fixed spherical bearing

Abstract

The present invention belongs to the field of bearing auxiliary measurement, and specifically relates to an auxiliary measurement device and measurement method for fixing a spherical bearing. The measuring device comprises: a butterfly nut, an upper pressure block, a hexagonal bolt, and a positioning shaft; the upper pressure block is designed as a circular ring with 3-4 bolt connection holes evenly distributed on it; the positioning shaft is designed as a flange structure with a raised center, with 3-4 bolt connection holes evenly distributed on the flange, and the bolt connection holes on the flange correspond to the bolt connection holes on the upper pressure block in a one-to-one manner; a spherical bearing is press-fitted into the mounting hole of a single joint; the inner hole of the spherical bearing and the short core shaft raised in the middle of the positioning shaft are clearance-matched, and the butterfly nut and the hexagonal bolt press the positioning shaft flange, the upper pressure block, and the single joint to fix the spherical bearing.

Description

Technical Field

[0001] The invention belongs to the field of bearing auxiliary measurement, and in particular relates to an auxiliary measurement device and a measurement method for a fixed spherical bearing. Background Art

[0002] Spherical joint bearings are a type of sliding bearing consisting of an inner ring and an outer ring. Their sliding surfaces are inner and outer spherical surfaces. They have the characteristics of strong load-bearing capacity, impact resistance, self-alignment, and good lubrication. They are widely used in aerospace, automobiles, engineering machinery, automation equipment and other fields, especially in the aerospace field. Spherical joint bearings are used in the main struts and pitch rods of helicopters. They are generally key force transmission components. The accuracy of the axis of the spherical joint bearing directly affects the force transmission effect and directly affects flight safety.

[0003] With the increasing number of helicopter and other maintenance services, the work of regular inspection of the center distance of the (C, D) main reducer strut holes is increasing. One end of the main reducer strut is a single-ear joint with a spherical bearing, and the other end is a double-ear joint with a fixed bushing. It is a key force transmission component of the helicopter. The center distance tolerance of the main reducer strut hole is generally required to be ±0.05mm. The dimensional deviation of the center distance of the hole affects the installation accuracy of the main reducer and the power transmission effect of the helicopter.

[0004] In order to ensure the hole center distance tolerance requirement of ±0.05mm, the main reducer support rod processing process is complicated. The spherical bearing bushing hole and the double-ear bushing hole are assembled using temperature difference interference fit. After assembly, the inner hole is bored to ensure the center size and tolerance of the two holes, and then the spherical bearing is installed using a press-fit process.

[0005] Since the inner ring of the bearing can rotate freely around the center of the ball after installation, it is not easy to remeasure the hole center distance, which brings great difficulties to the measurement of the hole center distance after assembly. In the past, in order to avoid measuring the center distance of the main reducer hole after assembly during the processing and manufacturing process, the hole center distance was measured with a three-coordinate measuring machine in the previous process and after boring the inner hole, and it was used to replace the post-assembly dimension for delivery. After on-site assembly inspection during final assembly, the hole center distance deviation met the use requirements.

[0006] With the continuous increase in helicopter maintenance business, the work of regular inspection (C, D) of the center distance of the main reducer strut hole is increasing. The center distance of the main reducer strut hole after use obviously needs to be re-measured. For those main reducer struts that were originally qualified but were found to be unqualified, they need to be returned to the original production unit to remove the fixed bushings and spherical bearings. The removed spherical bearings and fixed bushings are often deformed and scratched and cannot be reused. New fixed bushings need to be made, spherical bearings need to be purchased again, and they need to be re-assembled and bored before they can be delivered for use. This seriously restricts the maintenance delivery cycle of the main reducer struts and increases manufacturing and processing costs. Summary of the Invention

[0007] Purpose of the invention: To design an auxiliary measuring device and measuring method for fixed spherical bearings, which can directly measure the inner hole of the spherical bearings by means of a three-coordinate measuring instrument, accurately measure the position of the rotating sphere center of the spherical bearings, and then measure the center distance of the main reducing strut holes in the case, thereby improving the acceptance rate of new main reducing struts during inspection, reducing the repair rate of regular inspections, and avoiding the situation where qualified products are measured as unqualified, which requires time-consuming, labor-intensive, and costly repairs.

[0008] Technical Solution

[0009] In a first aspect, an auxiliary measuring device for fixing a spherical plain bearing is provided, comprising: a butterfly nut, an upper pressing block, a hexagonal bolt, and a positioning shaft;

[0010] The upper pressing block is designed as a circular ring with 3-4 bolt connection holes evenly distributed on it;

[0011] The overall design of the positioning shaft is a flange structure with a convex middle. There are 3-4 bolt connection holes evenly distributed on the flange. The bolt connection holes on the flange correspond to the bolt connection holes on the upper pressure block one by one.

[0012] The mounting hole of the single joint is press-fitted with a spherical plain bearing;

[0013] The inner hole of the spherical bearing and the short core shaft raised in the middle of the locating shaft are clearance-matched, and the butterfly nut and the hexagonal bolt press the locating shaft flange, the upper pressure block and the single joint to fix the spherical bearing.

[0014] Furthermore, the height of the short core shaft is less than half of the total height of the spherical plain bearing.

[0015] Furthermore, the perpendicularity deviation between the flange of the positioning shaft and the short core shaft is less than 0.01.

[0016] In a second aspect, an auxiliary measurement method for a fixed spherical bearing is provided, the method comprising:

[0017] Fix the product to be tested with the spherical bearing on the three-coordinate measuring platform;

[0018] Installing the auxiliary measuring device for fixing the spherical plain bearing according to any one of the first aspects onto the product to be tested having the spherical plain bearing;

[0019] First, use a three-coordinate measuring machine to measure several points on the upper end face of the spherical plain bearing to establish the plane where the upper end face of the spherical plain bearing is located. Then use a three-coordinate measuring machine to measure several points on the inner hole of the spherical plain bearing to establish the axis where the inner ring of the spherical plain bearing is located. Then, obtain the intersection point of the upper end face of the spherical plain bearing and the axis where the inner ring is located.

[0020] Move the spatial position of the intersection point downward along the axis by half the height of the spherical bearing, which is the center of the sphere where the inner ring of the spherical bearing is located.

[0021] Furthermore, before fixing the product to be measured with the spherical bearing on the three-coordinate measuring platform, the method further includes:

[0022] First, clean the surface of the inner ring of the spherical bearing to be measured, ensure that the auxiliary measuring device designed above is within the regular inspection period and has no bumps or scratches on the surface, and that the preliminary preparations for three-coordinate measurement are in place according to the standards.

[0023] Furthermore, the auxiliary measuring device for fixing the spherical plain bearing according to any one of the first aspects is installed on a product to be tested having a spherical plain bearing, comprising:

[0024] Insert the locating shaft into the inner hole of the spherical bearing from bottom to top, so that the lower end face of the single joint of the product to be tested fits with the upper end face of the locating shaft; then press the upper pressure block from top to bottom on the upper end face of the single joint, and fix the locating shaft and the upper pressure block together through 3 sets of hexagonal bolts and butterfly nuts, thereby completely fixing the inner ring of the spherical bearing.

[0025] Furthermore, the three sets of hexagonal bolts and butterfly nuts need to be pre-tightened before being tightened uniformly.

[0026] Beneficial effects:

[0027] 1: Convenient measurement. The measuring device has a simple structure, is easy to use and reliable, and solves the problem of difficult measurement of the center position of the inner ring of the spherical plain bearing;

[0028] 2. The measurement results are accurate and reliable. This auxiliary measuring device eliminates the indirect measurement error of the hole-shaft fit clearance through direct measurement, and then finds the center position of the inner ring of the spherical plain bearing through a reasonable and effective three-coordinate measurement method, eliminating the perpendicularity deviation between the axis center of the positioning shaft 4 of the measuring device and its end face, and also eliminating the assembly perpendicularity deviation between the positioning shaft 4 and the single joint 6. In other words, it avoids the measurement error of the perpendicularity deviation that is proportionally amplified in the direction of the axis of the inner ring of the bearing with the center center of the inner ring of the spherical plain bearing as the origin. By combining this auxiliary measuring device with this measurement method, ignoring the measurement accuracy error of the three-coordinate measuring instrument itself, the center position of the spherical plain bearing can theoretically be measured without deviation. This is an effective solution for the center measurement of spherical plain bearings with high precision requirements.

[0029] 3: Reduce costs and increase efficiency. By combining this auxiliary measuring device with this measuring method, the one-time inspection pass rate of new products is improved, the repair rate is reduced, the production repair efficiency is improved, and unnecessary repair costs are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural schematic diagram of an auxiliary measuring device for fixing spherical plain bearings. DETAILED DESCRIPTION

[0031] Most of the existing measurements involving the center of the sphere in the inner hole of a spherical plain bearing use a laser tracker to measure the spatial position after assembly. The applicant mainly studies the measurement of the center distance of the support rod hole with a spherical plain bearing. This is for regular inspection of parts after use or measurement after new production. Due to the high dimensional accuracy requirements, a three-coordinate measuring machine is currently used for measurement.

[0032] Auxiliary measuring devices for spherical bearings are mostly designed to achieve a state where the two end faces and the axis of the spherical bearing inner hole are as close to perpendicular as possible by fitting the clearance between the main core shaft (target base) and the inner hole of the spherical bearing, and by pressing and fixing the upper and lower end faces of the spherical bearing. The axis of the spherical bearing axis is fitted by measuring the axis of the extended axis of the main core shaft of the auxiliary device (target base). Although the cumulative error is reduced by combining various accessories to form a dedicated target base, it is still essentially an indirect measurement method. The error has a greater impact in situations where the product itself has high tolerance requirements. For example, the center distance tolerance of the main speed reducer support rod hole is generally ±0.05mm. During indirect measurement, due to the influence of factors that cannot be eliminated, such as the assembly clearance and the verticality deviation between the core shaft and the end face of the auxiliary measuring device itself, the verticality deviation is proportionally amplified as the extension length of the main core shaft (target base) increases. Although the auxiliary measuring device has been finely processed, its comprehensive measurement deviation is generally around 20-30%, which has a greater impact on occasions where the measurement product itself requires high precision. The detection is not unique, and qualified products may be measured as unqualified, which requires time-consuming, labor-intensive and costly rework.

[0033] The present invention provides an auxiliary measuring device for fixing a spherical plain bearing. The inner hole of the spherical plain bearing can be directly measured by a three-coordinate measuring instrument. The center position of the spherical plain bearing and the center distance of the main reducing strut hole can be theoretically measured without error by a reasonable and effective measuring method, thereby improving the qualified rate of the one-time inspection of new products, reducing the rework rate, improving the production rework efficiency, and reducing unnecessary rework costs.

[0034] Therefore, the present invention determines the center position of the inner ring of the spherical joint bearing through an effective three-coordinate measurement method. By combining this auxiliary measurement device with this measurement method, if the measurement accuracy error of the three-coordinate measuring instrument itself is ignored, the center position of the spherical joint bearing can theoretically be measured without deviation. It is an effective solution for the measurement of the center of the spherical joint bearing with high precision requirements.

[0035] The present invention provides an auxiliary measuring device for fixing a spherical bearing, such as Figure 1 As shown, it includes a butterfly nut 1, an upper pressure block 2, a hexagonal bolt 3, and a positioning shaft 4. The overall structure is simple and easy to process, and the product to be measured consists of a joint 6 with a spherical bearing 5.

[0036] The upper pressure block 2 is located at the upper part of the device and is designed as a circular ring. 3-4 bolt connection holes are arranged on it. It is fixed to the upper end surface of the single joint 6 by applying pressure through the butterfly nut 1 and the hexagonal bolt 3;

[0037] The positioning shaft 4 is located at the lower part of the device. The overall design is a flange shape with a protrusion, on which 3-4 bolt connection holes are arranged. The clearance fit is achieved between the short core shaft protruding in the middle and the inner hole of the spherical bearing. The flange end face of the positioning shaft 4 is pressed against the lower end face of the upper pressure block 2 by the butterfly nut 1 and the hexagonal bolt 3 to fix the single joint 6 and the spherical bearing.

[0038] How to use the device: insert the short core shaft with the protrusion in the middle of the positioning shaft 4 into the inner hole of the joint bearing from the lower end face of the joint bearing 5, place the upper pressure block 2 on the upper end face of the joint bearing, and fix it with hexagonal bolts and butterfly nuts.

[0039] The present invention provides an auxiliary measurement method for a fixed spherical bearing, comprising:

[0040] First, clean the surface of the inner ring of the spherical bearing to be measured, ensure that the auxiliary measuring device designed above is within the regular inspection period and has no bumps or scratches on the surface, and that the preliminary preparations for three-coordinate measurement are in place according to the standards.

[0041] Step 1: Fix the product to be tested with a spherical bearing, such as the main support rod mentioned above, on the three-coordinate measuring platform.

[0042] The second step: insert the positioning shaft 4 into the inner hole of the spherical bearing from bottom to top, so that the lower end face of the single joint 6 of the main reducing support rod fits with the upper end face of the positioning shaft 4; then press the upper pressure block 2 from top to bottom on the upper end face of the single joint 6 of the main reducing support rod, and fix the positioning shaft 4 and the upper pressure block 2 together through 3 sets of hexagonal bolts 3 and butterfly nuts 1, thereby completely fixing the inner ring of the spherical bearing.

[0043] Step 3: First, use a three-dimensional coordinate measuring machine to measure several points on the upper end face of the spherical plain bearing to establish the plane where the upper end face of the spherical plain bearing is located. Then, use a three-dimensional coordinate measuring machine to measure several points on the inner hole of the spherical plain bearing to establish the axis of the spherical plain bearing inner ring. Then, find the intersection point between the upper end face of the spherical plain bearing and the axis of the inner ring. Finally, move the spatial position of the aforementioned intersection point in the direction of the axis of the spherical plain bearing inner ring by half the height of the spherical plain bearing. This is the selected sphere center where the spherical plain bearing inner ring is located.

[0044] Case 1: Struts with spherical plain bearings are typically key force-transmitting components in helicopters. The center-to-center distance tolerance of the strut holes is typically ±0.05mm, requiring high machining precision and complex manufacturing processes. The spherical plain bearing bushing and the double-ear bushing holes are assembled using a temperature differential interference fit. After assembly, the inner bore is bored to ensure the center dimensions and tolerances of the two holes, and then the spherical plain bearing is installed using a press-fit process. Because the inner ring of the bearing rotates freely about the center of the ball after installation, re-measuring the center-to-center distance is difficult, which presents significant challenges in measuring the center-to-center distance after assembly. To avoid measuring the center-to-center distance of the main strut holes after assembly, the manufacturing process previously used a three-dimensional coordinate measuring machine (CMM) to measure the center-to-center distance in the pre-process and after boring the inner bore. This measurement was then used as a replacement for the post-assembly dimension. After on-site assembly inspection during final assembly, the center-to-center distance deviation met the requirements. This auxiliary measuring device can now be used to perform CMM measurement after the struts are fully machined and assembled, accurately measuring the center-to-center distance of the strut holes. This optimizes the process flow and eliminates the need for on-site assembly inspection during final assembly.

[0045] Case 2: With the continuous increase in helicopter maintenance and repair work, the number of regular inspections of the center distances of the main (C and D) main strut holes has increased. The center distances of the main strut holes after use clearly need to be remeasured. Some main struts that were originally qualified but were tested as unqualified due to measurement device errors need to be returned to the original manufacturer to remove the fixed bushings and spherical plain bearings. The removed spherical plain bearings and fixed bushings are often deformed and damaged, making them unusable. New fixed bushings must be manufactured, and new spherical plain bearings must be purchased. Reassembly and boring are then required before they can be put back into service, severely restricting the maintenance lead time of main struts and increasing manufacturing costs. An auxiliary measurement device for fixed spherical plain bearings has been designed. Using a three-dimensional coordinate measuring machine, the inner bore of the spherical plain bearing can be directly measured, solving the problem of difficult measurement of the inner bore of the spherical plain bearing. This device avoids the influence of indirect measurement factors such as assembly clearance and the perpendicularity deviation between the auxiliary measurement device's core shaft and the end face. Furthermore, the perpendicularity deviation amplifies the error proportionally with the extension length of the main core shaft (target base).

[0046] The present invention designs an auxiliary measuring device for fixing joint bearings, which can directly measure the inner hole of the joint bearing through a three-coordinate measuring instrument, solving the problem that the inner hole of the joint bearing is difficult to measure; the direct measurement method is used for measurement, avoiding the dimensional error caused by the (assembly) hole-axis matching clearance during the existing indirect measurement; through a reasonable and effective three-coordinate measurement method, the center point position of the inner ring of the joint bearing is found, eliminating the verticality deviation. The verticality (shape position) error that is proportionally magnified in the direction of the axis of the inner ring of the joint bearing with the center point of the inner ring of the joint bearing as the origin; through this auxiliary measuring device combined with this measuring method, the measurement accuracy error of the three-coordinate measuring instrument itself is ignored, and the center point position of the shutdown bearing can theoretically be measured without deviation, which is an effective solution for the measurement of the center point of the joint bearing with high precision requirements; the measuring device has a simple structure, is easy to manufacture, and is convenient and reliable to use; the manufacturing process of the strut with the joint bearing is optimized, and the original inner hole of the joint bearing cannot be measured after assembly, and the size after assembly can only be replaced by measuring the hole spacing of the previous process, and can now be measured after assembly.

Claims

1. An auxiliary measurement method for fixed spherical bearings, characterized in that: The method includes: Fix the product to be tested with the spherical bearing on the three-coordinate measuring platform; The auxiliary measuring device for fixing the joint bearing is installed on the product to be tested with the joint bearing; the auxiliary measuring device for fixing the joint bearing comprises: a butterfly nut (1), an upper pressure block (2), a hexagonal bolt (3), and a positioning shaft (4); the upper pressure block (2) is designed as a circular ring as a whole, and 3-4 bolt connection holes are evenly distributed on it; the positioning shaft (4) is designed as a flange structure with a protrusion in the middle, and 3-4 bolt connection holes are evenly distributed on the flange, and the bolt connection holes on the flange correspond to the bolt connection holes on the upper pressure block (2) in position; the joint bearing (5) is press-fitted into the mounting hole of the single joint (6); the inner hole of the joint bearing and the short core shaft protruding in the middle of the positioning shaft are clearance-matched, and the butterfly nut (1) and the hexagonal bolt (3) press the positioning shaft (4), the upper pressure block (2) and the single joint (6) to fix the joint bearing; First, use a three-coordinate measuring machine to measure several points on the upper end face of the spherical plain bearing to establish the plane where the upper end face of the spherical plain bearing is located. Then use a three-coordinate measuring machine to measure several points on the inner hole of the spherical plain bearing to establish the axis where the inner ring of the spherical plain bearing is located. Then, obtain the intersection point of the upper end face of the spherical plain bearing and the axis where the inner ring is located. Move the spatial position of the intersection point downward along the axis by half the height of the spherical bearing, which is the center of the sphere where the inner ring of the spherical bearing is located.

2. The method according to claim 1, characterized in that Before fixing the product to be measured with the spherical bearing on the three-coordinate measuring platform, the method further includes: First, clean the surface of the inner ring of the spherical bearing to be measured, ensure that the auxiliary measuring device designed above is within the regular inspection period and has no bumps or scratches on the surface, and that the preliminary preparations for three-coordinate measurement are in place according to the standards.

3. The method according to claim 1, characterized in that Install the auxiliary measuring device for fixing the spherical plain bearing on the product to be tested with the spherical plain bearing, including: Insert the locating shaft into the inner hole of the spherical bearing from bottom to top, so that the lower end face of the single joint of the product to be tested fits with the upper end face of the locating shaft; then press the upper pressure block from top to bottom on the upper end face of the single joint, and fix the locating shaft and the upper pressure block together through 3 sets of hexagonal bolts and butterfly nuts, thereby completely fixing the inner ring of the spherical bearing.

4. The method according to claim 3, characterized in that The three sets of hexagonal bolts and butterfly nuts need to be pre-tightened before being tightened together.

5. The method according to claim 1, wherein The height of the short mandrel is less than half of the total height of the spherical plain bearing.

6. The method according to claim 1, characterized in that The verticality deviation between the flange of the positioning shaft (4) and the short core shaft is less than 0.

01.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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