A method for measuring the clearance of large bearings in gear boxes

Abstract

The present invention discloses a method for measuring the clearance of a large bearing of a gearbox. The method comprises the following steps: by customizing a measuring shaft and a connecting tool for rotational connection, the connecting tool is fixedly connected to the end face of a hollow shaft at the end to be measured, the gearbox is placed horizontally during measurement, the balls of the bearing to be measured are aligned, the measuring shaft is pushed horizontally, the hollow shaft is moved axially to a first extreme position, the position is used as a measurement reference position, the measuring shaft is pulled in the opposite direction, the hollow shaft is moved axially in the opposite direction to a second extreme position, the displacement of the position relative to the reference position is measured, and the displacement is the clearance measurement value of the bearing to be measured. The present invention breaks the traditional inherent method of placing the gearbox vertically to measure the bearing clearance of the output shaft, and the horizontal placement method realizes the rotatability of the output shaft. The balls of the bearing to be measured can be aligned before measuring the clearance, and the uneven distribution of the balls caused by non-rotation is eliminated. The measurement is convenient, time-saving, and measurement efficiency is improved, and the accuracy of clearance measurement can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of gear boxes, and in particular to a method for measuring the clearance of a large bearing of a gear box. Background Art

[0002] With the requirement of lightweight vehicles, adaptive gearbox has become a new structural project explored and developed in the gear transmission system of 400km / h high-speed trains. At present, the axle box built-in bogie gearbox has been applied abroad, and the research on this technology in China has just started. The main feature of this type of gearbox is that it can reduce the unsprung weight of the bogie, thereby reducing the impact between the transmission device and the track, and reducing the maintenance and operation costs of the vehicle.

[0003] Rail transit gearboxes are in variable load and high vibration conditions for a long time, so their safety and stability are required to be extremely high. Bearings are an important part of gearboxes. The selection and adjustment of gearbox bearing clearances have a great impact on the rolling fatigue life, temperature rise, noise, vibration, and mechanical operation accuracy of the bearings. The large clearance adjustment of adaptive frame-mounted gearboxes has always been a difficult problem in domestic assembly. Among them, how to accurately measure the bearing clearance of the gearbox is particularly important. The large gear side bearings of rail transit gearboxes generally use tapered roller bearings. The applicant has developed a gearbox with herringbone gear transmission between gears and a hollow shaft at the output end. There are mainly two ways to measure the clearance of the large end bearings of existing shaft-mounted gearboxes. If these two conventional methods are used for measurement, there will be insurmountable difficulties:

[0004] 1. Lifting method: Place the gearbox vertically and use the flange interface tooling to lift the hollow shaft at the output end. Since the output end is light, the center of gravity of the overall gearbox with two-stage transmission is biased toward the input end, causing the gearbox to tilt (about 40°) after lifting. Due to the special structure of the herringbone gear, the input shaft will get stuck during rotation, and the input shaft and output shaft cannot rotate. The balls of the bearing are unevenly distributed, and the bearing clearance value cannot be accurately measured.

[0005] 2. Jack method: Place the gearbox vertically, and make a flat support ejection tooling that matches the output shaft end face according to the output shaft structure of the project, and use the jack ejection method to measure the maximum clearance. Similarly, due to the principle of the center of gravity of the box, it still tilts toward the center of gravity after ejection, resulting in the same result as the lifting measurement, and the accurate value of the clearance measurement cannot be guaranteed.

[0006] Therefore, it is necessary to redesign a measurement method to improve the accuracy of measuring the clearance of large bearings in gearboxes. Summary of the invention

[0007] The purpose of the present invention is to propose a method for measuring the clearance of a large bearing of a gear box in view of the shortcomings of the prior art, which is convenient for measurement, saves time, improves efficiency, and can improve the accuracy of clearance measurement.

[0008] The technical solution to achieve the purpose of the present invention is:

[0009] A method for measuring the clearance of a large bearing of a gear box comprises the following steps:

[0010] Step S1: according to the end surface structure of the hollow shaft at the output end of the gearbox, a matching connecting tool is manufactured, and the connecting tool is fixedly installed in the end surface hole of the hollow shaft;

[0011] Step S2: making a measuring shaft and rotatably mounting the measuring shaft on a connecting fixture, keeping the measuring shaft coaxially matched with the hollow shaft;

[0012] Step S3: Place the gearbox horizontally, align the balls of the bearing to be tested, push the measuring shaft horizontally, move the hollow shaft axially to the first extreme position, take this position as the measurement reference position, then pull the measuring shaft in the opposite direction, move the hollow shaft axially in the opposite direction to the second extreme position, measure the displacement of this position relative to the reference position, and this displacement is the clearance measurement value of the bearing to be tested.

[0013] Furthermore, in step S3, a support plate is threadedly mounted on the measuring shaft, both ends of the support plate extend to the gear box and are fixedly connected to the gear box, and the measuring shaft is rotated forward or reversely to move the measuring shaft in the horizontal direction.

[0014] Furthermore, a sleeve is provided at one end of the measuring shaft away from the hollow shaft, and a rotating driving member arranged perpendicular to the measuring shaft is connected to the sleeve.

[0015] Furthermore, the rotary drive member is a torque wrench. When driving the measuring shaft to rotate, the torque of the torque wrench is preset to be T, wherein T=0.2dF, d is the nominal diameter of the thread on the measuring shaft, and F is the axial force for pulling the hollow shaft to move horizontally.

[0016] Furthermore, in step S3, the displacement is measured by a micrometer, the micrometer is fixed on the gearbox through a base, and the head of the micrometer is arranged perpendicular to the flange surface of the connecting tooling and maintains contact with the flange surface, and the flange surface is parallel to the end face of the hollow shaft.

[0017] Furthermore, two micrometers are symmetrically arranged along the circumferential direction.

[0018] Furthermore, when the hollow shaft moves axially to a first limit position, the micrometer is adjusted to zero, and when the hollow shaft moves axially to a second limit position, the reading of the micrometer is the clearance measurement value of the bearing to be tested.

[0019] Furthermore, if the clearance measurement value is repeatedly measured at least three times and the error of the repeatedly measured clearance measurement values ​​is within the range of 0.01 mm, the measurement is determined to be valid, and the measured effective clearance measurement values ​​are averaged, otherwise the measurement is repeated.

[0020] Furthermore, the initial circumferential position of the hollow shaft is marked, and the input shaft is rotated so that the output shaft synchronously rotates at least 6 circles and overlaps with the initial circumferential position, thereby completing the alignment of the balls of the bearing to be tested.

[0021] Furthermore, the connecting tooling and the measuring shaft are connected through an angular contact ball bearing, and a first bearing pressure plate and a second bearing pressure plate are respectively provided on both sides of the angular contact ball bearing, and the outer ring and the inner ring are respectively interference fit with the inner ring of the connecting tooling and the outer ring of the measuring shaft, the inner ring of the first bearing pressure plate presses the outer ring of the angular contact ball bearing, and the outer ring of the second bearing pressure plate presses the inner ring of the angular contact bearing, and the clearance measurement value is the sum of the actual clearance value of the bearing to be measured and the clearance value of the angular contact bearing.

[0022] By adopting the above technical solution, the present invention has the following beneficial effects:

[0023] (1) The present invention breaks the traditional inherent method of placing the gearbox vertically to measure the bearing clearance of the output shaft. The gearbox is placed horizontally and transitioned through a connecting tooling, and a measuring shaft that rotates coaxially with the hollow shaft is set. The hollow shaft is pulled horizontally by the measuring shaft through the connecting tooling to move, thereby realizing the measurement of the bearing clearance. At the same time, compared with the traditional vertically placed gearbox, the horizontal placement method realizes the rotatability of the output shaft. Compared with the existing test method, the balls of the bearing to be tested can be arranged before measuring the clearance, eliminating the uneven distribution of the balls caused by non-rotation. It is not only convenient to measure, saves time, and improves the measurement efficiency, but also can improve the accuracy of the clearance measurement.

[0024] (2) The present invention provides a support plate that is threadedly matched with the measuring shaft, and fixes the support plate in the gear box. By rotating the measuring shaft, the axial movement and position retention of the measuring shaft can be achieved under the action of the threaded match, which is convenient for measuring the displacement difference between two extreme positions.

[0025] (3) The present invention pre-installs a rotating drive member perpendicular to the measuring axis through a sleeve structure, which is convenient for driving the measuring axis to rotate under the action of an external force, thereby facilitating measurement.

[0026] (4) The rotary drive member of the present invention is a torque wrench, which can directly set an appropriate torque so that the measuring shaft can not only drive the hollow shaft to move but also stop rotating the measuring shaft after the hollow shaft moves into place, thereby avoiding deformation and failure of the entire measuring tool due to excessive force. At the same time, it can prevent excessive force from pressing the outer ring and ball of the bearing to be tested and making them unable to rotate, resulting in the inability to align the bearing to be tested, causing the clearance to be unable to be accurately measured, and avoid forced rotation, resulting in abnormal wear of the inner and outer ring raceways of the bearing.

[0027] (5) The present invention uses a micrometer to measure the displacement change of the hollow shaft, which is reliable, has a simple structure, and has a low measurement cost.

[0028] (6) The present invention has two symmetrical working tables, which can measure the clearance values ​​of two symmetrical measuring points at the same time and take the average value, thereby further improving the measurement accuracy.

[0029] (7) The present invention measures the clearance value multiple times and strictly controls the measurement error, thereby further improving the measurement accuracy.

[0030] (8) The present invention drives the output shaft to rotate by rotating the input shaft, thereby completing the alignment of the balls at the bearing end to be measured at the output end, and marking the initial circumferential position of the hollow shaft during the process, thereby ensuring that the points measured at the same circumferential position are at the same point, thereby solving the problem of inaccurate clearance caused by the shape and position tolerance of the measuring tooling, and further improving the measurement accuracy.

[0031] (9) The present invention adopts angular contact ball bearings to realize the rotational connection between the measuring shaft and the connecting tooling. The structure is simple and the rotation is flexible. The ball bearings have good rotation flexibility and are easy to align the bearings. At the same time, the friction is small, and it can withstand large axial loads. The load is stable, and it has high rigidity and can maintain a stable working state when the load changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings, wherein:

[0033] Figure 1 It is a schematic diagram of the test tool structure of the present invention.

[0034] The reference numerals in the accompanying drawings are:

[0035] Connecting fixture 1, annular connecting ear 1-1, measuring shaft 2, angular contact ball bearing 3, first bearing pressure plate 4, second bearing pressure plate 5, supporting plate 6, micrometer 7, box body 100, hollow shaft 200, tapered roller bearing 300. DETAILED DESCRIPTION

[0036] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] (Example 1)

[0038] This embodiment is applied to the measurement of large bearing clearance of adaptive gearbox, such as Figure 1 As shown, the gearbox housing 100 is made of aluminum alloy, the gear shaft at the output end is a hollow shaft 200, which is rotatably mounted using a tapered roller bearing 300, and the gear positioning method relies entirely on the self-positioning of the two-stage transmission self-centering herringbone gear structure. Due to the particularity of the structure, the traditional clearance test method cannot accurately measure the clearance value, so a gearbox large bearing clearance measurement method is proposed, which specifically includes the following steps:

[0039] Step S1: according to the end surface structure of the hollow shaft at the output end of the gearbox, a matching connecting tool 1 is manufactured, and the connecting tool 1 is fixedly installed in the end surface hole of the hollow shaft;

[0040] The connecting tooling is a bearing seat, and an annular connecting ear 1-1 is provided at one end of the outer ring of the bearing seat. A screw hole corresponding to the end face of the hollow shaft is opened on the annular connecting ear 1-1, and a screw passes through the screw hole and is tightened on the end face of the hollow shaft to achieve fixed connection with the hollow shaft.

[0041] Step S2: manufacturing the measuring shaft 2 and rotatably mounting the measuring shaft 2 on the connecting fixture 1, and keeping the measuring shaft 2 coaxially matched with the hollow shaft;

[0042] Specifically, the connection fixture 1 and the measuring shaft 2 are connected by an angular contact ball bearing 3, which is flexible in rotation. The ball bearing has good rotation flexibility, which makes it easy to align the bearings. At the same time, the friction is small, and it can withstand large axial loads. The load is stable, and it has high rigidity, and it can maintain a stable working state when the load changes. The first bearing pressure plate 4 and the second bearing pressure plate 5 are respectively provided on both sides of the angular contact ball bearing 3, and the outer ring and the inner ring are respectively interference fit with the inner ring of the connection fixture 1 and the outer ring of the measuring shaft 2 to achieve preliminary fixation. The first bearing pressure plate 4 is fixed on the bearing seat by screws, and the inner ring presses the outer ring of the angular contact ball bearing 3. The second bearing pressure plate 5 is fixed on the right end of the measuring shaft 2 by screws, and the outer ring presses the inner ring of the angular contact bearing 3, thereby achieving axial fixation of the angular contact ball bearing.

[0043] Step S3: Place the gearbox horizontally, align the balls of the bearing to be tested, and manually draw a continuous straight line extending from the absolute fixed surface to the rotating surface, such as from the gearbox to the hollow shaft, as the rotation positioning point of the hollow shaft, thereby marking the initial circumferential position of the hollow shaft. Rotate the input shaft so that the output shaft rotates synchronously for at least 6 circles, which can ensure the consistency of the test results and have a strong fault tolerance. After the rotation is completed, the marked straight lines overlap, and the hollow shaft overlaps with the initial circumferential position, completing the alignment of the balls of the bearing to be tested, ensuring that the clearance measurement point is at the same point, and improving the measurement accuracy.

[0044] A support plate 6 is threadedly mounted on the measuring shaft 2, and both ends of the support plate 6 extend to the gear box and are fixedly connected to the gear box. A sleeve is provided at the left end of the measuring shaft 2, and a rotating drive component arranged perpendicular to the measuring shaft is connected to the sleeve. In this embodiment, a torque wrench is used as the rotating drive component, and the torque wrench is used to realize forward or reverse rotation of the measuring shaft 2 to realize horizontal movement of the hollow shaft.

[0045] The gearbox is fixed with a dial gauge 7 through a dial base, and the dial gauge 7 is set perpendicular to the flange surface of the connecting tool and keeps in contact with the flange surface, and the flange surface is parallel to the end surface of the hollow shaft. In order to improve the accuracy of measurement, two dial gauges 7 of this embodiment are symmetrically arranged along the circumference of the hollow shaft, and the line between the two dial gauges 7 is perpendicular to the line connecting the center points of the two-stage transmission gears of the gearbox.

[0046] The torque wrench is used to rotate the measuring shaft 2 in the positive direction, so that the measuring shaft drives the hollow shaft to translate to the right to the first limit position through the connecting tooling, and the two micrometers are adjusted to zero position, and this position is used as the measurement reference position. In actual measurement, the torque of the torque wrench is preset to T, where T = 0.2dF, d is the nominal diameter of the thread on the measuring shaft, and F is the axial force that pulls the hollow shaft to move horizontally. It is calculated based on the gearbox structure, the deadweight of the output end, and the principle of thread mechanics. It is mathematical common sense and will not be repeated here. By setting an appropriate torque, the measuring shaft can not only drive the hollow shaft to move, but also cannot continue to rotate the measuring shaft after the hollow shaft moves into place, so as to avoid deformation and failure of the entire measuring tooling due to excessive force. At the same time, it can prevent excessive force from pressing the outer ring of the bearing to be measured and the ball, making it impossible to rotate, so that the bearing to be measured cannot be aligned, resulting in the inability to accurately measure the clearance and avoid forced rotation, resulting in abnormal wear of the inner and outer ring raceways of the bearing.

[0047] Then use the torque wrench to rotate the measuring shaft in the opposite direction to move the hollow shaft in the opposite direction along the axial direction to the second extreme position. During the whole process, the head of the micrometer is in contact with the flange surface. At this time, the reading of the micrometer is the clearance measurement value of the bearing to be tested.

[0048] Repeat the measurement at least three times and if the error of the repeated clearance measurement values ​​is within 0.01mm, the measurement is considered valid and the average of the measured effective clearance measurement values ​​is taken, otherwise re-measure.

[0049] Considering that the clearance measurement value is the sum of the actual clearance value of the bearing to be tested and the clearance value of the angular contact bearing, the clearance value of the angular contact bearing needs to be subtracted when adjusting the clearance. The clearance value of the angular contact bearing 3 can be calculated based on the specifications and existing mathematical knowledge, which will not be repeated here.

[0050] The present invention breaks the traditional inherent method of placing the gear box vertically to measure the bearing clearance of the output shaft. The gear box is placed horizontally and transitioned through a connecting tooling, a measuring shaft that rotates coaxially with the hollow shaft is set, and the hollow shaft is pulled horizontally by the connecting tooling to move the measuring shaft, thereby realizing the measurement of the bearing clearance. At the same time, compared with the traditional vertically placed gear box, the horizontal placement method realizes the rotatability of the output shaft. Compared with the existing test method, the balls of the bearing to be tested can be arranged before measuring the clearance, and the uneven distribution of the balls caused by non-rotation is eliminated. Not only is the measurement convenient and time-saving, but the measurement efficiency is improved, and the accuracy of the clearance measurement can be improved.

[0051] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring the clearance of a large bearing of a gearbox, characterized in that: The following steps are involved: Step S1: according to the end surface structure of the hollow shaft at the output end of the gearbox, a matching connecting tool is manufactured, and the connecting tool is fixedly installed in the end surface hole of the hollow shaft; Step S2: making a measuring shaft and rotatably mounting the measuring shaft on a connecting fixture, keeping the measuring shaft coaxially matched with the hollow shaft; Step S3: Place the gearbox horizontally, align the balls of the bearing to be tested, push the measuring shaft horizontally, move the hollow shaft axially to the first extreme position, take this position as the measurement reference position, then pull the measuring shaft in the opposite direction, move the hollow shaft axially in the opposite direction to the second extreme position, measure the displacement of this position relative to the reference position, and this displacement is the clearance measurement value of the bearing to be tested.

2. A method for measuring the clearance of a large bearing of a gear box according to claim 1, characterized in that: In step S3, a support plate is threadedly mounted on the measuring shaft, two ends of the support plate extend to the gear box and are fixedly connected to the gear box, and the measuring shaft is rotated forward or reversely to move the measuring shaft in the horizontal direction.

3. A method for measuring the clearance of a large bearing of a gear box according to claim 2, characterized in that: A sleeve is provided at one end of the measuring shaft away from the hollow shaft, and a rotating driving member arranged perpendicular to the measuring shaft is connected to the sleeve.

4. A method for measuring the clearance of a large bearing of a gear box according to claim 3, characterized in that: The rotating drive member is a torque wrench. When driving the measuring shaft to rotate, the preset torque of the torque wrench is T, wherein T=0.2dF, d is the nominal diameter of the thread on the measuring shaft, and F is the axial force for pulling the hollow shaft to move horizontally.

5. The method for measuring the clearance of a large bearing of a gear box according to claim 1, characterized in that: In step S3, the displacement is measured by a micrometer, the micrometer is fixed on the gear box through a base, and the head of the micrometer is arranged perpendicular to the flange surface of the connecting tooling and keeps contact with the flange surface, and the flange surface is parallel to the end face of the hollow shaft.

6. A method for measuring the clearance of a large bearing of a gear box according to claim 3, characterized in that: The micrometers are symmetrically arranged in two along the circumferential direction.

7. A method for measuring the clearance of a large bearing of a gear box according to claim 4, characterized in that: When the hollow shaft moves axially to the first limit position, the micrometer is adjusted to zero position. When the hollow shaft moves axially to the second limit position, the reading of the micrometer is the clearance measurement value of the bearing to be tested.

8. A method for measuring the clearance of a large bearing of a gear box according to claim 5, characterized in that: The clearance measurement value is measured repeatedly for at least 3 times and the error of the repeatedly measured clearance measurement value is within the range of 0.01mm, the measurement is determined to be valid, and the measured effective clearance measurement values ​​are averaged, otherwise the measurement is repeated.

9. A method for measuring the clearance of a large bearing of a gear box according to claim 1, characterized in that: Mark the initial circumferential position of the hollow shaft, rotate the input shaft so that the output shaft rotates synchronously for at least 6 circles and overlaps with the initial circumferential position, and the balls of the bearing to be tested are aligned.

10. A method for measuring the clearance of a large bearing of a gear box according to claim 1, characterized in that: The connecting fixture and the measuring shaft are connected through an angular contact ball bearing. A first bearing pressure plate and a second bearing pressure plate are respectively provided on both sides of the angular contact ball bearing, and the outer ring and the inner ring are respectively interference fit with the inner ring of the connecting fixture and the outer ring of the measuring shaft. The inner ring of the first bearing pressure plate presses the outer ring of the angular contact ball bearing, and the outer ring of the second bearing pressure plate presses the inner ring of the angular contact bearing. The clearance measurement value is the sum of the actual clearance value of the bearing to be measured and the clearance value of the angular contact bearing.

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