A method for adjusting the gap of a current ratio meter movable system

Abstract

The present invention relates to a method for adjusting the gap of a current ratio meter's movable system, comprising: fixing the current ratio meter to be adjusted with a clamp, rotating the adjusting bearing so that the current ratio meter's movable system is in a state of a large gap, and the pointer rotates evenly and flexibly without stagnation and hysteresis; turning on the power supply to keep the current ratio meter in a working state, and the pointer swings symmetrically left and right at the midpoint; rotating the adjusting bearing until the pointer begins to stagnate, and marking this position as the reference position of the movable system gap; turning off the power supply, and then rotating the adjusting bearing to the callback position calculated by its pitch p, and powering on to verify whether the pointer state and swing amplitude meet the requirements of the movable system gap. If not, repeating steps 2 to 4 until the movable system gap meets the requirements; marking this position as the callback position and inspecting. This method is more accurate than the previous method of adjusting by feel, and solves the problem of poor consistency and accuracy in adjusting the gap of the movable system of the current ratio meter.

Description

Technical Field

[0001] The invention relates to the field of aircraft instrument performance test methods, and in particular to a method for adjusting the gap of a current ratio meter active system. Background Art

[0002] The current ratio meter is an important component of the aircraft instrument meter indicator. The structure and characteristics of the current ratio meter can be found in Figure 1 As shown, it includes: pointer, bridge plate 1, adjustment bearing 8, support 7 and open magnetic screen 5. There are two pairs of fixed coils Q13 and Q24 intersecting at an angle of 120°; the internal movable system 2 is as follows Figure 2 As shown, the movable system 2 is composed of a pointer, a connecting shaft 11, a rotating magnet 10, and an upper shaft tip 9 and a lower shaft tip 12. The shaft tips at both ends are supported by a pair of jewel bearings 6 fixed on the bridge plate 1 and the damper, respectively, and only the movable system 2 can rotate freely. The movable system 2 is precisely balanced by adjusting the position of the counterweight. The damper is made of copper material. The rotating magnet 10 generates eddy currents on the damper. The magnetic field of the eddy current interacts with the rotating magnet 10, and a braking torque that is always opposite to the direction of its movement is applied to the rotating magnet 10, which plays a damping role (that is, only the swing amplitude is reduced, and finally it stops at a certain position). The open magnetic screen 5 is made of soft magnetic material with high magnetic permeability. Its main function is to prevent the external magnetic field from interfering with the internal magnetic field of the current ratio meter and to prevent the internal magnetic field of the current ratio meter from affecting the normal operation of other nearby instruments. Since the current ratio meter has no mechanical device to generate a reaction torque, when the rotating magnet 10 stays in the direction of the synthetic magnetic field, the active part of the current ratio meter is in a balanced state. Because it has no conductive hairspring and active coil, it has a simple structure, is reliable to use, and is very small in size. It is very suitable as an aviation instrument for measuring signal strength.

[0003] The working principle of the current ratio meter is as follows: when working, the input signal of the sensor is transformed by the signal processing circuit to form a signal current and drive the two sets of coils Q1 3 and Q2 4 to generate their own magnetic fields. The two sets of coils work in a differential mode, and the magnetic fields of the two sets of coils are synthesized to form the corresponding signal magnetic field. When the sensor signal is minimum, the signal magnetic field points to the direction of the 0 scale line; when the signal is maximum, the signal magnetic field points to the direction of the maximum scale line. Under the traction of the signal magnetic field, the pointer points to the direction of the signal magnetic field, realizing the function of indicating the size of the sensor signal.

[0004] Relationship between the gap of the current ratio meter active system 2 and the pointer swing: It is difficult to directly measure the gap size of the current ratio meter active system 2, but it can be reflected by the pointer swing of the current ratio meter in the working state. Figure 2It can be seen that the active system 2 of the current ratio meter has two upper and lower shaft tips. When installed in the current ratio meter, the shaft tip moves freely in the jewel bearing 6. Under ideal conditions (i.e., the shaft tip is smooth and wear-free, and the jewel bearing has no cracks or scratches), by rotating the upper end of the adjusting bearing 8, when the gap distance is reduced to a certain extent (such as the upper shaft tip 9 lightly touches the jewel bearing 6, the shaft tip is not worn; or the shaft tip has been worn by the jewel bearing), the jewel bearing 6 hinders the movement of the shaft tip and generates a friction torque. When the current ratio meter is in the working state, the pointer swings with stagnation and hysteresis. Moreover, during the subsequent vibration screening, the upper shaft tip 9 will be more worn due to its close distance to the jewel bearing 6. When the gap of the active system 2 of the current ratio meter is within the appropriate range, the upper shaft tip 9 is not subjected to the friction torque, and the pointer of the current ratio meter swings and rotates evenly without stagnation in the working state. When the gap of the current ratio meter active system 2 exceeds the appropriate range, the pointer of the current ratio meter rotates evenly and without stagnation although it swings in the working state. However, when it is installed as a meter and vibrated for screening, the amplitude of the pointer swing will gradually increase with time, and the fatigue degree of the pointer will increase until the pointer breaks.

[0005] At present, the gap of the current ratio meter's active system is mainly adjusted by hand feel. Since the operators' experience and feelings are different, and there is no standardized inspection and testing method, even if there are standard samples as reference, the consistency and accuracy of the gap adjustment are poor. Therefore, the adjustment of the gap of the current ratio meter's active system has become an urgent problem to be solved. Summary of the invention

[0006] The present invention provides a method for adjusting the gap of a current ratio meter movable system in order to solve the above-mentioned problem.

[0007] The present invention achieves the above-mentioned purpose through the following technical scheme. The adjustment method includes the following steps: S1, fix the current ratio meter to be adjusted with a clamp, rotate and adjust the bearing 8 so that the movable system 2 is in a state of large gap, and the pointer rotates evenly and flexibly without sticking and hysteresis; S2, turn on the power supply, connect the current ratio meter with the signal generator, the drive circuit device and the DC regulated power supply, the DC regulated power supply outputs voltage to the drive circuit device, the signal generator outputs a control signal to the drive circuit device, and the other end of the drive circuit device outputs the converted signal to the current ratio meter, so that the current ratio meter is kept in a working state, and the pointer swings symmetrically left and right at the midpoint position; S3, rotate and adjust the bearing 8 Until the pointer starts to get stuck, mark this position as the reference position of the gap of the active system 2; S4, turn off the power, calculate the callback position, and according to the required reasonable gap value Δ, draw auxiliary scales on the current ratio meter bridge plate 1 to divide the bridge plate into N equal parts, where N is an integer and N is an even number. The callback position is the reference position described in step S3, rotated counterclockwise by 2 equal parts, and then rotated clockwise by 1 equal part; S5, rotate the adjusting bearing 8 to the callback position calculated in step S4, power on to verify whether the pointer state and swing amplitude meet the gap requirements of the active system 2. If not, repeat steps S2 to S5 until they meet the requirements, mark this position as the callback position and inspect it.

[0008] Preferably, the method for verifying that the pointer state and swing amplitude meet the gap requirements is: the pointer should rotate evenly and without stagnation in the low, high and normal temperature states; the pointer of the current ratio meter should swing slightly ≤±1 scale line during the 10-minute vibration screening process when it is installed into the table, and swing significantly ≤±1.5 scale line.

[0009] Preferably, the method of marking the reference position is to mark the reference position on the engraved line of the bridge plate 1 corresponding to the groove of the adjustment bearing 8.

[0010] Preferably, after marking the callback position, it is checked whether the interval between the reference position and the callback position is 1 equal division, and whether the adjustment bearing 8 is locked.

[0011] Preferably, the reasonable gap value Δ is determined by the result of a process vibration screening test in which current ratio meters with different gaps are assembled into a meter.

[0012] Preferably, the pointer swing position, amplitude and frequency of the current ratio meter in the working state are all controlled by the signal generator.

[0013] The beneficial effects of the present invention are:

[0014] The present invention provides a method for adjusting the gap of a movable system under the working state of a current ratio meter, and combines the theoretical calculation of the pitch of the adjusting bearing and the angle of the bridge plate to obtain a more accurate gap correspondence, and through experimental verification, determine the reasonable range of the gap size. The gap adjustment can also be checked using the interval between the reference position and the callback position to ensure the consistency and accuracy of the gap adjustment. It can solve the problem of poor consistency and accuracy caused by the different experience and feelings of the on-site operators in adjusting the gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the current ratio meter structure.

[0016] Figure 2 This is a schematic diagram of the activity system structure.

[0017] Figure 3 This is a schematic diagram of the bridge deck being divided equally according to angles.

[0018] Figure 4 This is a schematic diagram of the system electrical connections.

[0019] Figure 5 This is a schematic diagram of the drive circuit pin connection.

[0020] Figure 6 Comparison chart of process vibration screening results for current ratio meters with different gaps.

[0021] Figure 1 Middle: 1. Bridge plate, 2. Movable system, 3. Coil Q1, 4. Coil Q2, 5. Open magnetic screen, 6. Jewel bearing, 7. Pillar, 8. Adjustment bearing.

[0022] Figure 2 Middle: 9. Upper shaft tip, 10. Rotating magnet, 11. Connecting shaft, 12. Lower shaft tip. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Without departing from the essential content of the present invention, any obvious improvements, substitutions or modifications made by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. Specific embodiment:

[0025] See also Figure 1 and Figure 2The current ratio meter movable system 2 is composed of a pointer, a connecting shaft 11, a rotating magnet 10, and shaft tips at both ends (upper shaft tip 9 and lower shaft tip 12), and the shaft tips are supported by a pair of jewel bearings 6 on the current ratio meter bridge plate 1 and the damper, respectively. This method utilizes the characteristics of the movable system 2, and determines the reference position of the minimum gap between the jewel bearing 6 and the upper shaft tip 9 by the magnitude of the friction force between the jewel bearing 6 and the upper shaft tip 9 when the current ratio meter is in working state, and then adjusts the bearing back to the adjustment position calculated according to the pitch of the adjusting bearing, so that the clearance of the movable system 2 meets the requirements.

[0026] In order to determine the reasonable range of the gap, five current ratio meters of a certain type with different gap sizes in the active system 2 were installed in the table for vibration screening test. The test results are shown in Figure 6 When the gap is too large (about 0.03mm) or too small (about 0.01mm), the swing amplitude of the current ratio meter pointer increases to varying degrees after a period of vibration (≤10min), that is, a small swing exceeds the ±1 scale line, and a large swing exceeds the ±1.5 scale line. When the gap is in the range of about 0.02mm, the change in the swing amplitude of the current ratio meter pointer is very small. Therefore, it is determined that for this type of current ratio meter, a gap of 0.02mm is a reasonable range.

[0027] To this end, the gap is adjusted by drawing auxiliary scales on the current ratio meter bridge plate 1 to determine the reference position and the callback position. The current ratio meter bridge plate 1 is divided into 16 equal parts, and the corresponding gap of each equal part obtained by this division is about 0.02mm. Calculation method: The pitch p of the bearing is adjusted to 0.35mm, and the angle α between the scales is 360 / 16=22.5°, which is equivalent to the gap change Δ: 0.35×22.5 / 360=0.021875mm≈0.02mm. See the schematic diagram of the bridge plate 1 divided into equal parts according to angles. Figure 3 .

[0028] like Figure 4 As shown in FIG. 1 , in this embodiment, the regulation system consists of three parts: a DC regulated power supply, a driving circuit device, and a signal generator. The DC regulated power supply outputs a +15V voltage to power the driving circuit device, and the signal generator outputs a control signal to the driving circuit device. The internal connection diagram is shown in FIG. Figure 5 The other end of the driving circuit device outputs the converted signal to the current ratio meter. The pointer swing position, amplitude and frequency of the current ratio meter in working state are controlled by the signal generator.

[0029] The specific operation method is as follows:

[0030] 1. Preparation before adjustment

[0031] Fix the current ratio meter to be adjusted with the gap adjustment fixture, press Figure 4Connect the current ratio meter to the signal generator, circuit drive device and DC regulated power supply. Loosen the fastening nut and turn the adjusting bearing 8 to make the movable system 2 in a free state with a large gap. At this time, the pointer should rotate evenly and flexibly without stagnation and hysteresis. After the power is turned on, adjust the signal generator to make the pointer of the current ratio meter swing symmetrically left and right at the midpoint. The swing position, amplitude and frequency are controlled by the signal generator to keep the current ratio meter in the working state. The reference values ​​of the signal generator in this embodiment are DC offset (offset) 1.35V, AC amplitude (Ampl) 0.3V, and frequency (Freq) 0.5Hz. According to the actual swing of the pointer, the output of the signal generator can be appropriately adjusted for easy operation.

[0032] 2. Determine the reference position

[0033] First, use the clearance wrench to turn the adjusting bearing 8 on the bridge plate clockwise so that the jewel bearing 6 at the bottom lightly touches the upper shaft tip 9 of the current ratio meter. If there is obvious sticking when the pointer swings, mark this reference position on the engraved line of the bridge plate 1 corresponding to the groove of the adjusting bearing 8.

[0034] 3. Clearance adjustment

[0035] Turn off the power supply, and according to the engraved lines on the bridge plate 1, use the clearance adjustment wrench to rotate the adjustment bearing 8 counterclockwise by 2 equal parts, and then rotate it clockwise by 1 equal part, and adjust the pointer clearance to about 0.02mm. Turn on the power supply, and the pointer rotation state and swing amplitude should be the same as the preparation state before the clearance adjustment. If it does not meet the requirements, repeat the preparation before the clearance adjustment, determine the reference position, and the clearance adjustment steps until the clearance adjustment meets the requirements.

[0036] 4. Determine the callback position

[0037] After the clearance is adjusted to the required standard, the pointer should rotate evenly without stagnation. At this time, mark the engraved line on the bridge plate 1 corresponding to the groove on the adjusting bearing 8, which is the callback position.

[0038] 5. Current ratio meter finishing

[0039] Clean up the current ratio meter and use TB06-9 point seal on the adjusting bearing, lock the special nut, and clean up the appearance.

[0040] 6. Re-inspection and testing

[0041] The interval between the reference position and the callback position of the inspection mark should be 1 equal part; the pointer should rotate evenly and without stagnation in the working state. The inspection requirements are the same.

[0042] Test results: After adjusting the current ratio meter of the active system gap by the above method and assembling it into an indicator, a vibration test of 6.5 hours (including functional vibration of 1 hour and endurance vibration of 5.5 hours) was carried out according to the environmental technical requirements of a certain type of aircraft finished accessories. The verification results are shown in Table 1.

[0043]

[0044] It can be seen that when the gap of the current ratio meter active system is controlled within the range of 0.8 to 1.5 equal parts (i.e., about 0.02 mm), the pointer swing is small and stable during the vibration process. After applying this method, a pointer failure of an indicator that failed the regular inspection did not occur when the regular inspection test was repeated.

Claims

1. A method for adjusting the gap of a current ratio meter active system, It is characterized in that The adjustment method comprises the following steps: S1, fixing the current ratio meter to be adjusted with a clamp, rotating the adjustment bearing (8) so that the movable system (2) is in a state of large clearance, and the pointer rotates evenly and flexibly without stagnation and hysteresis; S2, connecting the power supply, connecting the current ratio meter with the signal generator, the drive circuit device and the DC regulated power supply, the DC regulated power supply outputs a voltage to the drive circuit device, the signal generator outputs a control signal to the drive circuit device, and the other end of the drive circuit device outputs a converted signal to the current ratio meter, so that the current ratio meter is kept in a working state, and the pointer swings symmetrically left and right at the midpoint position; S3, rotating the adjustment bearing (8) until the pointer begins to swing. Stuck phenomenon, mark this position as the reference position of the clearance of the active system (2); S4, turn off the power, calculate the callback position, and according to the required reasonable clearance value Δ, draw auxiliary scales on the current ratio meter bridge plate (1) to divide the bridge plate into N equal parts, N is an integer, and N is an even number, then the callback position is the reference position described in step S3 rotated counterclockwise by 2 equal parts, and then rotated clockwise by 1 equal part; S5, rotate the adjustment bearing (8) to the callback position calculated in step S4, power on to verify whether the pointer state and swing amplitude meet the clearance requirements of the active system (2), if not, repeat steps S2 to S5 until it meets the requirements, mark this position as the callback position and check.

2. A method for adjusting the gap of a current ratio meter active system according to claim 1, It is characterized in that The method to verify that the pointer state and swing amplitude meet the gap requirements is: the pointer should rotate evenly and without stagnation in low, high and normal temperature states; when the current ratio meter is installed into a meter and the pointer swings slightly during the 10-minute vibration screening process, it should swing by ≤±1 scale line, and by ≤±1.5 scale line.

3. A method for adjusting the gap of a current ratio meter active system according to claim 1, It is characterized in that The method of marking the reference position is to mark the reference position on the engraved line of the bridge plate (1) corresponding to the groove of the adjusting bearing (8).

4. A method for adjusting the gap of a current ratio meter active system according to claim 1, It is characterized in that After marking the callback position, check whether the interval between the reference position and the callback position is 1 equal division, and whether the adjustment bearing (8) is locked.

5. A method for adjusting the gap of a current ratio meter active system according to claim 1, It is characterized in that The reasonable gap value Δ is determined by the result of a process vibration screening test performed by assembling current ratio meters with different gaps into a meter.

6. A method for adjusting the gap of a current ratio meter active system according to claim 1, It is characterized in that When the current ratio meter is in working state, the pointer swing position, amplitude and frequency are all controlled by the signal generator.

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