A device and method for measuring the axial clearance of a two-axis platform of a seeker using a tooling shaft

Abstract

The application discloses a device and method for measuring the axial gap of a two-axis platform of a guide head by using a tool shaft, which can accurately measure the number of adjusting pads required to be added before assembly, so as to ensure that the axial gap reserved after assembly reaches the assembly requirement. The device comprises a motor thin shaft (1), a rotary variable thin shaft (2), a tool shaft pin (3), a tool shaft hole (4) and a nut (5). The tool shaft pin (3) is installed in the tool shaft hole (4) through a tolerance fit, so as to ensure the coaxiality of the motor thin shaft (1) and the rotary variable thin shaft (2). After installation, the tool shaft pin (3) and the tool shaft hole (4) are fixed through a jackscrew, so as to prevent relative displacement. The nut (5) is connected with the tool shaft pin (3) and the tool shaft hole (4) through threads.

Description

Technical Field

[0001] This invention belongs to the field of shaft assembly and relates to a device and method for measuring the axial clearance between two shaft platforms of a guide head using a tooling shaft. Background Technology

[0002] The axial clearance of the two-axis stabilization platform of the seeker is an important indicator in the seeker assembly process. It has a significant impact on subsequent indicators such as isolation, tracking accuracy, and high and low temperature performance. Excessive axial clearance will lead to tracking instability, especially during vibration, which may result in target loss. Insufficient axial clearance will lead to jamming during low temperature processes and excessive motor current.

[0003] The existing axial clearance is guaranteed by design tolerance during the design process. However, this will result in the tolerance range being much larger than the required axial clearance, and the machining cannot fully guarantee the accuracy. If the axial clearance cannot be accurately calculated, it is necessary to measure the axial clearance after assembly. If the measurement does not meet the requirements, it is necessary to disassemble and reassemble, and repeat this process multiple times. This will affect the mating surfaces of the shaft and the frame, and will also greatly slow down the assembly progress.

[0004] Therefore, accurately calculating the required number of adjustment shims before assembly can ensure that the axial clearance reserved after assembly meets the assembly requirements, reducing the process of repeated disassembly and assembly iterations, and greatly improving assembly efficiency. Summary of the Invention

[0005] This invention provides a device and method for measuring the axial clearance between the two axes of a guide head using a tooling shaft. It can accurately measure the number of adjustment shims that need to be added before assembly, thereby ensuring that the reserved axial clearance meets the assembly requirements after assembly.

[0006] The present invention is achieved through the following technical solution.

[0007] A device for measuring the axial clearance between two shaft platforms of a guide head using a tooling shaft includes a motor shaft (1), a resolver shaft (2), a tooling pin (3), a tooling hole (4), and a nut (5); wherein: the tooling pin (3) and the tooling hole (4) are installed with tolerance fit to ensure the coaxiality of the motor shaft (1) and the resolver shaft (2), and are fixed by set screws after installation to prevent relative displacement; the nut (5) is connected to the tooling pin (3) and the tooling hole (4) by threads respectively.

[0008] Beneficial effects of this invention:

[0009] 1. This invention comprehensively considers all factors that may cause changes in axial clearance, and can standardize and effectively ensure the addition of adjusting shims, thereby ensuring the assembly efficiency of the shaft system structure.

[0010] 2. This invention calculates the axial clearance after assembly, which allows for a more precise calculation of the number of shims to be added in practical applications.

[0011] 3. In this invention, the bearing mounting portion of the motor thin shaft and resolver thin shaft is machined to 0.02-0.04mm below the zero line; this machining method ensures that the bearing can be easily installed in actual applications.

[0012] 4. In this invention, the bearing mounting parts of the product shaft, namely the motor shaft and the resolver shaft, are machined to 0-0.05mm above the zero line; this method allows the bearings to be installed without damaging them. Attached Figure Description

[0013] Figure 1 A diagram showing the shaft system structure for mounting the motor shaft and the resolver shaft of this invention;

[0014] Among them, 1-motor thin shaft, 2-resolver thin shaft

[0015] Figure 2 A diagram showing the shaft system structure of the tooling pin, tooling hole, and nut for the present invention;

[0016] Among them, 3-tooling pin, 4-tooling hole, and 5-nut.

[0017] Figure 3 This is a cross-sectional view of the assembled tooling pin, tooling hole, and nut of the present invention.

[0018] Figure 4 A cross-sectional view of the shaft system structure for installing the tooling pin, tooling hole, and nut of the present invention;

[0019] Figure 5 This is a schematic diagram of the tooling pin of the present invention;

[0020] Figure 6 This is a schematic diagram of the shaft hole of the tooling of the present invention. Detailed Implementation

[0021] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary and are intended to illustrate the principles and spirit of the present invention, and are not intended to limit the scope of the present invention.

[0022] like Figure 1 , 2As shown, the present invention provides a device for measuring the axial clearance between the two shaft platforms of a guide head using a tooling shaft, comprising a motor thin shaft (1), a resolver thin shaft (2), a tooling shaft pin (3), a tooling shaft hole (4), and a nut (5); wherein: the tooling shaft pin (3) and the tooling shaft hole (4) are installed with tolerance fit to ensure the coaxiality of the motor thin shaft (1) and the resolver thin shaft (2), and are fixed by set screws after installation to prevent relative displacement; the nut (5) is connected to the tooling shaft pin (3) and the tooling shaft hole (4) by threads respectively.

[0023] This invention also proposes a method for measuring the original axial clearance based on the above-mentioned device, wherein the original axial clearance L0 is the sum of the tolerance reserved during the design process of the motor shaft and resolver shaft and the original clearance of the bearing installed on the frame; specifically, it includes the following steps:

[0024] Step 1.1: Machin the bearing mounting portion of the motor thin shaft and resolver thin shaft to 0.02-0.04mm below the zero line; this machining method ensures that the bearing can be easily installed.

[0025] Step 1.2: Assemble the motor shaft, resolver shaft, bearings, and frame;

[0026] Step 1.3: Adjust the dial indicator to zero from the motor shaft side or the resolver shaft side to measure the axial clearance. Measure three times, remove values ​​with excessive errors, and record the average value as the final axial clearance L0.

[0027] This invention also proposes a method for measuring the initial clearance of a bearing and frame assembly based on the above-mentioned device. The initial clearance L1 of the bearing and frame assembly is the initial clearance of the bearing installed on the frame after the tooling pin, tooling hole, and nut are assembled. Specifically, it includes the following steps:

[0028] Step 2.1: Attach the two internal nuts to the tooling shaft hole using threads, then connect the tooling shaft hole and the tooling shaft pin through a mating connection, and secure them with set screws;

[0029] Step 2.2: Assemble the assembled tooling shaft, bearing, and outer frame;

[0030] Step 2.3: Install the nuts onto the tooling shaft on the motor side, so that the two nuts clamp the inner ring of the bearing;

[0031] Step 2.4: Gently push the tooling shaft until the motor-side bearing reaches its limit position, install the outer nut of the resolver, and make the outer nut tightly against the inner ring of the bearing until the bearing reaches its limit position. Then rotate the inner nut to clamp the inner and outer nuts together to the inner ring of the resolver-side bearing.

[0032] Step 2.5: Measure the axial clearance at this point using a dial indicator;

[0033] Step 2.6: Following the same method, first clamp the resolver-side bearing, then clamp the motor-side bearing, and use a dial indicator to measure the axial clearance.

[0034] Step 2.7 Compare whether the measured values ​​on both sides are the same. If they are different, take the smaller value as the original clearance L1 of the bearing and frame assembly.

[0035] This invention also proposes a method for measuring the dimensional difference of the shaft end face based on the above-mentioned device, wherein the dimensional difference L2 of the shaft end face is the dimensional difference between the end face of the motor shaft and the motor tooling thin shaft, and between the resolver shaft and the resolver tooling thin shaft and the mounting surface; specifically, it includes the following steps:

[0036] Step 3.1: Take five points and measure the distance from the end face of the motor shaft and the resolver shaft to the mounting surface of the shaft frame, M0 for the motor and M0 for the resolver.

[0037] Step 3.2: Take five points and measure the distance from the end face of the motor shaft and the resolver shaft to the bearing mounting surface, respectively. N0 motor, N0 resolver;

[0038] Step 3.3: Calculate the difference between corresponding points M0 motor, M0 resolver and N0 motor, N0 resolver, which is the dimension K0 motor, K0 resolver from the mounting surface of the motor thin shaft and resolver thin shaft frame to the bearing mounting surface;

[0039] Step 3.4: Using the same method, measure the dimensions Kmotor and Kresolver from the mounting surface of the motor shaft and resolver shaft frame to the bearing mounting surface;

[0040] Step 3.5: Remove the points with larger errors from the five points, and take the average of the rest to obtain K0 motor, K0 resolver, K motor, and K resolver;

[0041] Step 3.6: Calculate and record the value of L2 = K motor - K0 motor + K resolver - K0 resolver.

[0042] This invention also proposes a method for measuring the axial clearance after the bearing, product shaft, and frame are assembled using the above-mentioned device. The axial clearance L3 after the bearing, product shaft, and frame are assembled is the original clearance of the bearing when it is installed on the frame in the product shaft state. Specifically, it includes the following steps:

[0043] Step 4.1: Machin the bearing mounting parts of the product shaft, i.e., the motor shaft and resolver shaft, to 0-0.05mm above the zero line; this method allows the bearings to be installed without damaging them.

[0044] Step 4.2: Assemble the motor shaft, resolver shaft, bearings, and frame according to the assembly drawing;

[0045] Step 4.3: Measure the axial clearance by adjusting the dial indicator to zero from the motor shaft or resolver shaft. Measure three times, remove values ​​with excessive errors, and take the average value as the axial clearance L3.

[0046] This invention also proposes a method for measuring axial clearance after assembly based on the above method. Specifically, the axial clearance L after assembly is calculated using the following formula:

[0047] L = L0 - (L1 - L3) - L2

[0048] Where L0 is the original axial clearance, L1 is the original clearance of the bearing and frame assembly, L2 is the dimensional difference of the shaft end face, and L3 is the axial clearance after the bearing, product shaft, and frame are assembled.

[0049] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A method for measuring axial clearance, characterized in that, This is achieved using a device that measures the axial clearance between the two shaft platforms of the guide head using a tooling shaft. The device includes a motor shaft (1), a resolver shaft (2), a tooling pin (3), a tooling hole (4), and a nut (5). The tooling pin (3) and the tooling hole (4) are installed with tolerance fit to ensure the coaxiality of the motor shaft (1) and the resolver shaft (2). After installation, they are fixed with set screws to prevent relative displacement. The nut (5) is connected to the tooling pin (3) and the tooling hole (4) by threads. The axial clearance measurement method includes: Measure the original axial clearance L0, which is the sum of the tolerance reserved during the design of the motor shaft and resolver shaft and the original clearance of the bearing installed on the frame; Measure the initial clearance L1 of the bearing and frame assembly. The initial clearance L1 of the bearing and frame assembly is the initial clearance of the bearing when it is installed on the frame after the tooling pin, tooling hole and nut are assembled. Measure the dimensional difference L2 between the shaft end faces; the dimensional difference L2 between the shaft end faces is the dimensional difference from the end face of the motor shaft to the motor thin shaft, and the resolver shaft to the resolver thin shaft to the mounting surface. Measure the axial clearance L3 after the bearing, product shaft, and frame are assembled; the axial clearance L3 after the bearing, product shaft, and frame are assembled is the original clearance of the bearing when it is installed on the frame in the product shaft state. The axial clearance L after assembly is calculated using the following formula: L = L0 - (L1 - L3) - L2 Where L0 is the original axial clearance, L1 is the original clearance of the bearing and frame assembly, L2 is the dimensional difference of the shaft end face, and L3 is the axial clearance after the bearing, product shaft, and frame are assembled.

2. The axial clearance measurement method as described in claim 1, characterized in that, Measuring the original axial clearance L0 specifically includes the following steps: Step 1.1: Machin the bearing mounting parts of the motor thin shaft and resolver thin shaft to 0.02-0.04mm below the zero line; Step 1.2: Assemble the motor shaft, resolver shaft, bearings, and frame; Step 1.3: Adjust the dial indicator to zero from the motor shaft side or the resolver shaft side to measure the axial clearance. Measure three times, remove values ​​with excessive errors, and record the average value as the final axial clearance L0.

3. The axial clearance measurement method as described in claim 1, characterized in that, Measuring the initial clearance L1 of the bearing and housing assembly specifically includes the following steps: Step 2.1: Attach the two internal nuts to the tooling shaft hole using threads, then connect the tooling shaft hole and the tooling shaft pin through a mating connection, and secure them with set screws; Step 2.2: Assemble the assembled tooling shaft, bearing, and outer frame; Step 2.3: Install the nuts onto the tooling shaft on the motor side, so that the two nuts clamp the inner ring of the bearing; Step 2.4: Gently push the tooling shaft until the motor-side bearing reaches its limit position, install the outer nut of the resolver, and make the outer nut tightly against the inner ring of the bearing until the bearing reaches its limit position. Then rotate the inner nut to clamp the inner and outer nuts together to the inner ring of the resolver-side bearing. Step 2.5: Measure the axial clearance at this point using a dial indicator; Step 2.6: Following the same method, first clamp the resolver-side bearing, then clamp the motor-side bearing, and use a dial indicator to measure the axial clearance. Step 2.7: Compare the measured values ​​on both sides. If they are different, take the smaller value as the original clearance L1 of the bearing and frame assembly.

4. The axial clearance measurement method as described in claim 1, characterized in that, Measuring the dimensional difference L2 between the shaft end faces specifically includes the following steps: Step 3.1: Take five points and measure the distance from the end face of the motor shaft and the resolver shaft to the mounting surface of the shaft frame, M0 for the motor and M0 for the resolver. Step 3.2: Take five points and measure the distance from the end face of the motor shaft and the resolver shaft to the bearing mounting surface, respectively. N0 motor, N0 resolver; Step 3.3: Calculate the difference between corresponding points M0 motor, M0 resolver and N0 motor, N0 resolver, which is the dimension K0 motor, K0 resolver from the mounting surface of the motor thin shaft and resolver thin shaft frame to the bearing mounting surface; Step 3.4: Using the same method, measure the dimensions Kmotor and Kresolver from the mounting surface of the motor shaft and resolver shaft frame to the bearing mounting surface; Step 3.5: Remove the points with larger errors from the five points, and take the average of the rest to obtain K0 motor, K0 resolver, K motor, and K resolver; Step 3.6: Calculate and record the value of L2 = K motor - K0 motor + K resolver - K0 resolver.

5. The axial clearance measurement method as described in claim 1, characterized in that, Measuring the axial clearance L3 after the bearing, product shaft, and frame are assembled includes the following steps: Step 4.1: Machin the bearing mounting parts of the product shaft, i.e., the motor shaft and resolver shaft, to 0-0.05mm above the zero line; Step 4.2: Assemble the motor shaft, resolver shaft, bearings, and frame according to the assembly drawing; Step 4.3: Measure the axial clearance by adjusting the dial indicator to zero from the motor shaft or resolver shaft. Measure three times, remove values ​​with excessive errors, and take the average value as the axial clearance L3.

Images