Servo accelerometer

Abstract

To reduce the positional misalignment of the pendulum relative to the yoke unit. [Solution] The servo accelerometer is characterized in that the inertial force generated in the pendulum 1, the current flowing through the torque coil wrapped around the torque cup, and the Lorentz force generated by the magnetic field in the yoke units 2 and 3, which are composed of a yoke, a pole piece, and a permanent magnet, balance each other. The pendulum 1 has a thin film wiring on its surface and comprises a support part fixed to the yoke, and a weight part suspended from the support part by a hinge and displaceable. The first engaging part 120 provided on the outer circumference of the support part and the second engaging parts 130 and 150 provided on the outer circumference of the yoke units are arranged at the same position in the circumferential direction of the torque coil.

Description

Technical Field

[0001] The present invention relates to a servo accelerometer using a pendulum.

Background Art

[0002] Conventionally, a servo accelerometer having a yoke unit forming a magnetic circuit and a pendulum oscillating with an input acceleration has been put on the market. The yoke unit is composed of a permanent magnet generating magnetic flux, a pole piece through which the magnetic flux passes inside, and a yoke. The pendulum is composed of a weight portion whose displacement occurs due to acceleration, a hinge suspending the weight portion, and a support portion suspending the weight portion via the hinge. A torquer cup around which a torquer coil is wound is fixed to the surface of the weight portion, and it oscillates receiving acceleration together with the weight portion. The displacement of the weight portion is detected as the capacitance generated in the gap of the electrodes formed in the weight portion, the yoke unit, etc., and the current converted and amplified into a voltage is supplied to the torquer coil. The displacement of the weight portion is controlled to zero by the magnetic field in the magnetic gap of the yoke unit and the Lorentz force (restoring force) generated by the current flowing through the torquer coil. Since the restoring force at this time becomes equal to the inertial force, the acceleration can be detected from the torquer coil current.

[0003] For example, in the servo accelerometer of Patent Document 1, the pendulum is fixed sandwiched between two yoke units. At the moment when the yoke unit contacts and fixes the pendulum, since the pendulum can move freely with respect to the yoke unit, due to vibrations generated during the assembly work or unintended stresses, etc., the position of the pendulum may shift with respect to the yoke unit and be fixed. When the pendulum is fixed with a shift from the ideal position with respect to the yoke unit, the torquer coil or the torquer cup may contact the yoke unit and the weight portion may not move, which may cause the servo speedometer accelerometer to malfunction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] To reduce the positional misalignment of the pendulum relative to the yoke unit. [Means for solving the problem]

[0006] To solve the above problems, the servo accelerometer of the present invention is a servo accelerometer in which the inertial force generated in a pendulum, the current flowing in a torque coil wrapped around a torque cup, and the Lorentz force generated by the magnetic field in a yoke unit composed of a yoke, a pole piece, and a permanent magnet are balanced. The pendulum has a thin film wiring on its surface and a support part fixed to the yoke, and a weight part suspended from the support part by a hinge and displaceable. The first engaging part provided on the outer circumference of the support part and the second engaging part provided on the outer circumference of the yoke unit are arranged at the same position in the circumferential direction of the torque coil. [Effects of the Invention]

[0007] The present invention provides a servo accelerometer that can reduce the positional misalignment of the pendulum relative to the yoke unit. [Brief explanation of the drawing]

[0008] [Figure 1] Exploded perspective view of the servo accelerometer in Example 1 [Figure 2] Cross-sectional view of the servo accelerometer in Example 1 [Figure 3] Front view of the pendulum in Example 1 [Figure 4] Enlarged cross-sectional view of the area around the torque coil in Example 1 [Figure 5] A schematic diagram showing the ideal fixed state of the pendulum support in Example 1. [Figure 6] A schematic diagram showing the fixed state of the support part of the misaligned pendulum in Example 1. [Figure 7]Figure showing the method of positioning the support portion of the pendulum in the radial direction using the protrusion of the yoke [Figure 8] Figure showing the fixed state of the support portion of the pendulum in Example 1 [Figure 9] Front view of the assembly of the pendulum and the yoke unit 2 in Example 1 [Figure 10] Perspective view of the expanded assembly of the pendulum, the yoke unit 2, the yoke unit 3, and the positioning jig in Example 1 [Figure 11] Perspective view of the assembly of the pendulum, the yoke unit 2, and the positioning jig in Example 1 [Figure 12] Perspective view of the assembly of the pendulum, the yoke unit 2, the yoke unit 3, and the positioning jig in Example 1 [Figure 13] Figure showing the positions of the depression of the support portion and the depression of the yoke unit 2 in Example 1 [Figure 14] Enlarged view of the positioning jig, the support portion, and the yoke unit 2 in Example 1 [Figure 15] Figure showing the positions of the depression of the yoke unit 2 and the depression of the yoke unit 3 in Example 1 [Figure 16] Enlarged view of the positioning jig, the yoke unit 2, and the yoke unit 3 in Example 1 [Figure 17] Example of the first engaging portion and the second engaging portion in Example 1 [Figure 18] Example of the second engaging portion in Example 1 [Figure 19] Exploded perspective view of the servo accelerometer in Example 2 [Figure 20] Cross-sectional view of the servo accelerometer in Example 2 [Figure 21] Front view of the pendulum in Example 2 [Figure 22] Developed perspective view of the assembly in Example 2 [[ID=A7]] [Figure 23] Perspective view of the assembly of the pendulum, the yoke unit 2, and the positioning jig in Example 2 [Figure 24] Perspective view of the assembly of the pendulum, the yoke unit 2, the positioning jig, and the seal band in Example 2 [Figure 25]Perspective view of the assembly of the pendulum, yoke unit 2, positioning jig, seal band, and yoke unit 3 in Example 2 [Figure 26] Rear view of yoke unit 3 in Example 2 [Figure 27] Diagram showing the positions of the depression in the support part and the depression in yoke unit 2 in Example 2 [Figure 28] Enlarged view of the positioning jig, support part, and yoke unit 2 in Example 2 [Figure 29] Exploded perspective view of the servo accelerometer in Example 3 [Figure 30] Cross-sectional view of the servo accelerometer in Example 3 [Figure 31] Perspective view of the assembly in Example 3 [Figure 32] Developed perspective view of the assembly of the pendulum, yoke unit 2, yoke unit ३, positioning jig, and seal band in Example 3 [Figure 33] Rear view of yoke unit 3 in Example 2 [Figure 34] Rear view of the assembly of the pendulum, yoke unit 2, yoke unit 3, positioning jig, and seal band in Example 3 with the circular yoke removed [Figure 35] Diagram showing the positions of the through-holes in yoke unit 2 and yoke unit 3 in Example 3

Modes for Carrying Out the Invention

[0009] The following describes one embodiment of the present invention. Figure 1 shows the configuration of one embodiment of the servo accelerometer according to this invention, and is an exploded perspective view of the components. Figure 2 shows a cross-sectional view of the servo accelerometer. The servo accelerometer is a device made up of stacked disc-shaped and cylindrical parts, and the central axes of these parts coincide. These parts are assembled for each pendulum 1, yoke unit 2, and 3, and each assembly is fixed by a sealing band 23. In the description below, the designation indicating direction is the central axis direction of the servo accelerometer, the central axis direction of the torque coils 11 and 12 which are parallel to the acceleration detection axis 30 is the axial direction, the direction perpendicular to the axial direction and extending from the central axis toward the outer circumference is the radial direction, and the rotational direction around the central axis is the circumferential direction. Similarly, the direction in which the pendulum 1 is viewed from the yoke unit 3 is the front side, and the opposite direction in which the pendulum 1 is viewed from the yoke unit 2 is the back side.

[0010] The pendulum 1 has Torca cups 13 and 14 fixed to the surface of the pendulum base 10, and Torca coils 11 and 12 fixed to the outer circumference of Torca cups 13 and 14. Methods of fixing Torca cups 13 and 14 include bonding with epoxy adhesive, mechanical fixing using screws, and joining using welding. Suitable materials for Torca cups 13 and 14 are non-magnetic and lightweight materials such as aluminum alloy, titanium alloy, and resin materials. Torca coils 11 and 12 are assemblies of metal wire wound around the outer circumference of Torca cups 13 and 14, and the material of the core requires high conductivity, so copper, copper alloy, aluminum, and aluminum alloy are suitable. The outer circumference of the metal wire has an insulating layer such as polyurethane, polyester, or polyesterimide, and further on the outer circumference there is a fusion layer mainly of polyvinyl butyral, polyamide, or polyester. After the metal wire is wrapped around the outer circumference of the Torca cups 13 and 14, the shape of the Torca coils 11 and 12 is fixed by the adhesion of adjacent fusion layers. Methods for adhering the fusion layers include applying a solvent or softening and melting by heating.

[0011] The configuration of yoke units 2 and 3 is described below. One end of yokes 15 and 16 is closed by circular yokes 17 and 18, while the other end, the open end face, is in contact with the base 10 of the pendulum. Pole pieces 19 and 20 are positioned at the center of the holes in the open end faces of yokes 15 and 16, and cylindrical permanent magnets 21 and 22 are in contact with pole pieces 19 and 20 and housed inside yokes 15 and 16. In this configuration, magnetic flux passes through each component, and a magnetic circuit is formed by yoke units 2 and 3. An annular magnetic gap is formed between the inner circumferential surface of the open end of yokes 15 and 16 and the outer circumferential surface of pole pieces 19 and 20. After the assembly of the servo accelerometer, torque coils 11 and 12 are housed in the magnetic gap, and the magnetic field passes through the torque coil. The seal band 23 is then fixed to the outer circumference of yokes 15 and 16 using adhesive or the like.

[0012] The permanent magnets 21 and 22 are neodymium, samarium cobalt, or alnico magnets, magnetized in the thickness direction, while the yokes 15 and 16, the circular yokes 17 and 18, and the pole pieces 19 and 20 are made of soft magnetic materials. The permanent magnets 21 and 22, the circular yokes 17 and 18, and the pole pieces 19 and 20 are fixed together with adhesive, while the yokes 15 and 16 and the circular yokes 17 and 18 are joined by laser welding.

[0013] Figure 3 shows the pendulum 1. The weight portion 10a of the tongue-shaped pendulum 1 is located within the frame of the cylindrical support portion 10b. The support portion 10b is fixed to the yokes 15 and 16 via fixing portions 10f that are positioned symmetrically on both sides of the support portion 10b. The constituent material and shape of the fixing portion 10f include a thin film structure made of metal, an adhesive layer made of adhesive, and a protruding structure made of the same material as the support portion 10b. As shown in Figure 3, there are three fixing portions 10f for each side of the support portion 10b, so there are three fixing points for the support portion 10b by the yokes 15 and 16, but various fixing configurations are possible without being limited to this. For example, the fixing portion 10f may be a pair of horseshoe-shaped thin film structures symmetrically arranged on both sides of the support portion 10b, resulting in only one fixing point for the support portion 10b by the yokes 15 and 16. Similarly, it is possible to have two or four fixing points for the support portion by the yokes 15 and 16.

[0014] The weight portion 10a is suspended from the support portion 10b by a hinge 10c positioned between the fixed portions 10f. When acceleration occurs in the direction of the acceleration detection axis 30, the thin-walled hinge 10c elastically deforms relative to the support portion 10b, and the displaceable weight portion 10a rotates around the longitudinal center of the hinge 10c as an axis.

[0015] The manufacturing method for the weight portion 10a, support portion 10b, and hinge 10c is described below. A base plate is cut from a metal or glass material and polished to produce a substrate with the desired thickness and surface accuracy. The surface of the pendulum 1 serves as the reference point for the positions of the Torca cups 13 and 14 and the yokes 15 and 16. Therefore, the higher the surface accuracy of the pendulum surface, the higher the assembly accuracy of each component. Next, the shapes of the weight portion 10a, support portion 10b, and hinge 10c are manufactured by removing a portion of the base material using cutting, wet etching, laser, etc.

[0016] The electrode surfaces 15e and 16e on the surfaces of the yokes 15 and 16, and the thin-film electrode 10d on the surface of the weight portion 10a opposite them, function as two electrodes of a capacitor. The displacement of the weight portion 10a caused by the input acceleration changes the capacitance between the electrodes, and the difference is detected as a voltage, which is differentially amplified by a servo amplifier (not shown). A servo current based on the capacitance difference is then supplied to a pair of torque coils 11 and 12. This electrical signal detecting the capacitance and the servo current flow to the servo amplifier via the thin-film electrode 10d, the thin-film wiring 10e formed on the surfaces of the hinge 10c and support portion 10b, the metal wire 24, and the terminal 25.

[0017] The torque coils 11 and 12 are subjected to a Lorentz force by the magnetic field and servo current formed by the yoke units 2 and 3. When acceleration is applied in a direction perpendicular to the plane of the pendulum base 10 (acceleration detection axis 30), the accelerated weight 10a is displaced. However, by controlling the servo current so that the displacement is zero, the inertial force acting on the pendulum and the Lorentz force are balanced. At this time, the magnitude of the servo current directly corresponds to the magnitude of the acceleration along the acceleration detection axis 30, so acceleration can be detected.

[0018] The assembly method for pendulum 1, yoke unit 2, and yoke unit 3 is explained below. First, assemble pendulum 1, yoke unit 2, and yoke unit 3 separately. However, at this stage, the metal wire 24 is not joined to pendulum 1 and yoke unit 2. Next, fix pendulum 1 to the open end face of yoke unit 2, and join the metal wire 24 to the support part 10b and terminal 25 by wire bonding or soldering. Next, bring the open end face of yoke unit 3 into contact with pendulum 1, and secure yoke units 2 and 3 with sealing bands.

[0019] This explains why high assembly precision is required for servo accelerometers. Figure 4 shows a magnified view of the area around the torque coil 11 in Figure 2. The torque coil 11 and torque cup 13 are placed in the magnetic air gap 100 formed in the gap between the pole piece 19 and the yoke 15. The servo accelerometer has a gap 101 between the torque cup 13 and the pole piece 19 or permanent magnet 21, and a gap 102 between the torque coil 11 or torque cup 13 and the yoke 15. If the yoke unit 2 or yoke unit 3 is fixed in a position that is shifted from the ideal position relative to the pendulum 1, the gap 101 or gap 102 may disappear. In this case, the torque cup 13 or torque coil 11 will come into contact with surrounding parts, the weight 10a will not move even when subjected to acceleration, and the accelerometer may malfunction. If the radial dimension of the magnetic air gap 100 is increased to avoid contact between these parts, the magnetic flux density passing through the magnetic air gap decreases. This reduces the Lorentz force acting on the coil, lowering the upper limit of detectable acceleration. Since the Lorentz force acting on the torque coils 11 and 12 is proportional to the length of the metal wire, increasing the length of the metal wire is effective in increasing the upper limit of detectable acceleration. In that case, the number of turns of the metal wire wound around the torque cup increases, so the torque coil becomes larger in the radial direction. One way to increase the number of turns without changing the volume of the torque coil is to reduce the diameter of the metal wire. However, in a servo speedometer that operates with a constant voltage, the maximum current that can flow through the metal wire decreases as the resistance of the torque coil increases, so the contribution to improving the Lorentz force is limited. In addition, reducing the diameter of the metal wire causes a decrease in strength, which may cause the metal wire to break during the winding work on the torque cup. Another method is to increase the maximum current applied to the metal wire, but increasing the applied voltage may cause the temperature of the metal wire to rise, leading to melting or breakage. Furthermore, an increase in the internal temperature of the servo speedometer could cause deformation of the support part 10b due to thermal expansion, potentially degrading the performance of the servo speedometer.In servo speedometers with such large detectable accelerations, the radial dimension of the magnetic air gap 100 is small, and the torque coil must be made larger in the radial direction, so the gaps 101 and 102 tend to be small. To suppress malfunctions due to contact between parts, a highly accurate assembly method is required in which the positional misalignment between the pendulum 1 and the yoke units 2 and 3 is smaller than the reduced gaps 101 and 102.

[0020] Figure 5 shows a schematic cross-sectional view of the part where the support part 10b is sandwiched and fixed between the yoke 15 and yoke 16. Specifically, it is a diagram extracted from the area around the support part 10b by cutting the servo accelerometer along line AA' in Figure 3. When an ideal assembly is achieved, the yoke 15 and yoke 16 are positioned symmetrically with respect to the support part 10b in the radial and circumferential directions. Since the points of application of the forces 103 that the support part 10b receives from each component via the fixing part 10f coincide in the circumferential and radial directions, the support part 10b does not experience bending stress even when subjected to two opposing forces 103. Figure 6 shows the case where the positions of the yoke 15 and yoke 16 are offset in the circumferential direction with respect to the support part 10b. The points of application of the forces 103 that the support part receives become asymmetrical, and the support part 10b deforms due to the rotational moment. Thus, by reducing the positional misalignment between the support part 10b and the yokes 15 and 16, deformation of the support part 10b can be suppressed.

[0021] One method for fixing the pendulum unit to the yoke units 2 and 3 is to provide an adhesive layer between the fixing part 10f of the support unit and the yokes 15 and 16, as shown in Figure 5. However, this method deforms the support unit 10b due to the hardening and shrinkage of the adhesive. Furthermore, if the size and position of the two adhesive layers formed on both sides of the support unit 10b are not equal, the point of application of the fixed load received by the support unit 10b via the yokes 15 and 16 will be asymmetrical, similar to the structure shown in Figure 6, and the support unit 10b will deform due to a rotational moment. Similarly, even when the support unit 10b is mechanically fixed to the yokes 15 and 16 using screws or the like, deformation of the support unit 10b may occur.

[0022] Deformation of the support part 10b may cause a decrease in sensor performance or malfunction. When stress is applied to the hinge 10c due to the deformation of the support part 10b, the correspondence between the displacement of the weight part 10a and the input acceleration changes, and the difference from the original relationship becomes an error. Alternatively, the weight part 10a may be pressed against the yokes 15 and 16 by the hinge 10c and become immobile. If the force (fixed load) received from the yoke is reduced in order to reduce the amount of deformation of the support part 10b, the static friction force generated between the fixed part 10f and the yokes 15 and 16 will decrease, and when the servo accelerometer is subjected to a radial impact, the positions of the pendulum 1 and the yoke units 2 and 3 may shift, which may cause the accelerometer to malfunction.

[0023] As mentioned above, the assembly of pendulum 1, yoke unit 2, and yoke unit 3 requires minimizing misalignment in both the circumferential and radial directions. For example, one method to minimize misalignment of each component is to measure the relative distance between them and then move and fix them based on that measurement. However, this method would require a huge amount of time for assembly, and manufacturing costs would likely increase. In small servo accelerometers, the components are also small, making it difficult to implement mechanisms for holding and moving the components, thus increasing the manufacturing cost of the assembly equipment. Furthermore, since the thin hinge 10c is fragile, the fixing and movement of pendulum 1 during assembly requires mechanisms and assembly procedures that minimize the stress applied to the hinge 10c as much as possible. Thus, assembly methods that measure the relative distance between components are prone to problems in terms of productivity and economics.

[0024] This section describes an assembly method in which the position of a component is determined by bringing another component to be assembled into contact with a fixed component. In the assembly of the pendulum 1 and the yoke unit 2 and yoke unit 3, the axial position of the component is determined by the contact between the fixed portion 10f of the support portion 10b and the open end faces of the yoke units 2 and 3. In the radial and circumferential directions, the servo speedometer described in Patent Document 1 does not have a structure that allows the position of the pendulum to be determined relative to the yoke unit. Furthermore, adding such a structure to existing components may lead to a decrease in the performance or an increase in the size of the servo accelerometer. For example, when fixing the pendulum 1 to the yoke unit 2, a structure is needed to restrict the radial movement of the pendulum 1 in order to suppress radial displacement. Figure 7 shows a cross-sectional view of a configuration in which a projection 15g of the yoke unit 2 is provided in the radial direction of the support portion 10b to restrict radial movement. Figure 8 shows an enlarged schematic diagram of the seal band 23, support portion 10b, and yokes 15 and 16 in Figure 2. Compared to Figure 8, the radial dimension of the yoke 15 in Figure 7 is larger than that of the support part 10b due to the addition of the protrusion 15g, resulting in a larger servo accelerometer in the radial direction. On the other hand, if the pendulum 1 is made smaller in the radial direction, the protrusion 15g can be provided while maintaining the size of the servo accelerometer. In that case, the weight part 10a will also be made smaller in the radial direction, so the area of ​​the thin film electrode 10d will decrease, or the diameters of the torque coils 11 and 12 will decrease. If the area of ​​the thin film electrode 10d decreases, the change in capacitance with respect to the displacement of the weight part 10a will decrease, the gain of the servo current will decrease, and the frequency response of the servo acceleration will decrease. If the diameters of the torque coils 11 and 12 decrease, the length of the metal wires forming the torque coils 11 and 12 tends to decrease. Since the Lorentz force acting on the torque coils 11 and 12 is proportional to the length of the metal wires, reducing the diameter of the torque coils 11 and 12 will decrease the Lorentz force obtained by the servo current, and reduce the range of acceleration that can be detected. Thus, relying solely on assembly methods that involve contact between components for positioning can sometimes lead to a decrease in the performance of servo accelerometers.

[0025] This section describes an assembly method for determining the position of parts using a jig. This method involves preparing a jig that serves as a position reference, and then either bringing each part into contact with the jig or limiting the range of misalignment of each part to keep the misalignment of each part within a certain range. In the servo accelerometer described in Patent Document 1, the pendulum and yoke unit are cylindrical in shape, and the parts are structured to move freely in the circumferential direction. Therefore, assembly accuracy in the circumferential direction tends to decrease. For radial positioning of parts, an assembly can be performed by placing a jig that restricts the movement of parts on the outer circumference and stacking and fixing each part inside it. Specifically, this can be done by dropping each part into a hole slightly larger than the outer diameter of each part and fixing it in place. However, depending on the position of each part, the outer circumference of the pendulum support may protrude from the outer circumference of the yoke unit. If a part such as a seal band 23 that fixes the outer circumference of the yoke unit is attached in this state, the support part protruding from the yoke and the fixing part may come into contact, potentially causing the support part 10b to break or deform under stress. If the outer diameter of the support part is made significantly smaller than the outer diameter of the yoke in order to suppress this, the pendulum 1 will be more prone to radial misalignment relative to the yoke units 2 and 3 by that difference, and the assembly accuracy will decrease.

[0026] To maintain the performance of the accelerometer, the outer dimensions of pendulum 1 must be made as large as possible to closely match the outer dimensions of yoke units 2 and 3. However, during assembly, the outer dimensions of the pendulum must not protrude beyond the outer dimensions of the yoke units. To achieve this, a high-precision assembly method using jigs is required, which does not rely on the outer dimensions of the pendulum or yoke units for positioning.

[0027] The relationship between the process of joining the metal wire 24 to the thin film wiring 10e and terminal 25 and the assembly process of the pendulum 1, yoke unit 2, and yoke unit 3 will be explained. Figure 9 shows a front view of the assembly with the yoke unit 2 fixed to the pendulum 1 and the metal wire 24 connected. In the process of joining the metal wire 24, the joining device needs to be placed on the front side of Figure 9, so the metal wire 24 cannot be joined when the pendulum 1, yoke unit 2, and yoke unit 3 are assembled. In other words, the yoke unit 3 will be fixed to the pendulum 1 after the process of joining the metal wire 24 is completed.

[0028] When the metal wire 24 is joined while the pendulum 1 and the yoke unit 2 are not fixed, the energy such as heat and pressure generated during joining is applied to the support part 10b and terminal 25, which may cause the positions of the pendulum 1 and the yoke unit 2 to shift. If this shift is large, the appropriate energy cannot be applied to the processing part, making it difficult to obtain a good joint. When temporarily fixing the pendulum 1 to the yoke unit 2 and joining the metal wire 24, it is necessary to release the fixation of the pendulum 1 before fixing the yoke unit 3 to the pendulum 1. However, in the servo accelerometer of Patent Document 1, the pendulum has a structure that moves freely relative to the yoke unit, so there is a possibility that the metal wire may be pulled and break. Thus, it is necessary to minimize the positional shift that occurs before and after joining the metal wire 24.

[0029] (Example 1) Figure 10 is a perspective view showing the positioning jig 110 and each component unfolded in the axial direction to illustrate the relationship between each component in the assembly of the pendulum 1 and the yoke units 2 and 3. The pendulum 1 and the yoke units 2 and 3 have recesses 120, 130, and 150 on their outer circumference, which are first and second engaging parts located at the same position in the circumferential direction. In assembly, the positioning jig 110 is positioned to be in contact with or close to the recesses 120, 130, and 150 of the first or second engaging parts, thereby restricting the radial and circumferential movement of each component. The positioning jig 110 is fixed by being pressed against the recess 130 of the second engaging part of the yoke unit 2 by a mechanism (not shown), or it is fixed at a certain distance from the yoke unit 2 in the radial direction. The positioning jig 110 has the function of moving radially, and by having its side surface enter the recess of each component, it has the function of stopping the radially outward movement of each component and the circumferential movement of each component.

[0030] The assembly method for the pendulum 1 and the yoke unit 2 will be explained. Figure 11 shows a perspective view of the assembly with the metal wire 24 joined to the pendulum 1 and the yoke unit 2. The positioning jig 110 is fixed to the recess 130 of the second engagement part of the yoke unit 2, and the pendulum 1 is placed on the upper surface of the yoke unit 2 while passing the positioning jig 110 through the recess 120 of the first engagement part of the support part. Alternatively, after the pendulum 1 is in contact with the upper surface of the yoke unit 2, the positioning jig 110 may be inserted into the recess 120 of the first engagement part and the recess 130 of the second engagement part to adjust the position of each part. The role of the positioning jig 110 is to determine the position of each part, and the order of positioning in the assembly process is not specified.

[0031] When joining the metal wire 24, the energy applied to the parts may cause the position of the pendulum 1 or the yoke unit 2 to shift. However, the positioning jig 110 restricts the movement of the parts, so the positional shift of the pendulum 1 and the yoke unit 2 remains constant. Alternatively, a different fixing jig may be used to press the support part 10b against the yoke unit from above to secure it. Even if positional shifts occur in each part when the fixing jig is removed from the parts after joining the metal wire 24 to the thin film wiring 10e and the terminal 25, the positioning jig 110 keeps these positional shifts constant, thereby suppressing the cutting of the metal wire 24.

[0032] The assembly method for yoke unit 2, yoke unit 3, and seal band 23 will be explained. Insert the positioning jig 110 into the recess 150 of the second engaging part of yoke unit 3 and place yoke unit 3 on the upper surface of pendulum 1. Figure 12 shows the assembly of pendulum 1, yoke unit 2, yoke unit 3, and positioning jig 110. Next, apply a load from the end faces of yoke unit 2 and yoke unit 3 so as to sandwich the pendulum 1 and fix the pendulum 1 to yoke units 2 and 3. With the load applied to the assembly, slide the positioning jig 110 radially using a mechanism (not shown) to remove it, attach the seal band 23 to the assembly, and fix yoke unit 2, yoke unit 3, and the seal band.

[0033] The positioning method of the pendulum 1 and the yoke unit 2 using the positioning jig 110 will be described in detail. Figure 13 shows a front view of the assembly shown in Figure 11, and Figure 14 is an enlarged view showing the area around the positioning jig 110 in Figure 13. The end shape of the recess 130 of the second engaging part of the yoke unit 2 and the end shape of the recess 120 of the first engaging part of the support part are located at the same position in the circumferential direction. The outer shape 123 of the support part is smaller than the outer shape 133 of the yoke unit 2, and the recess 120 of the first engaging part of the support part is located inward from the recess 130 of the second engaging part of the yoke unit 2. There are at least two recesses 120 of the first engaging part of the support part and two recesses 130 of the second engaging part of the yoke unit 2, and in a plane perpendicular to the axial direction, the angle θ around the center of the part, connecting the center of the engaging part of each part to the center of the part and the center of the circumferentially adjacent engaging parts, is all 180 degrees or less. By making the distance between one positioning jig and another smaller than the outer shape of the pendulum 1, the movement of the pendulum 1 is stopped by the positioning jig, thereby suppressing displacement of the pendulum 1 in the circumferential and radial directions.

[0034] The diameter of the smallest inscribed circle 131 of the innermost end shape in the radial direction in the recess of the yoke unit 2 is smaller than the diameter 121 of the smallest inscribed circle of the innermost end shape in the recess of the pendulum support part. Because a gap is created between the support part 10b and the positioning jig 110, the support part 10b is less likely to receive radial force from the positioning jig 110. Creating a gap between the support part 10b and the positioning jig 110 reduces deformation of the support part 10b and contributes to maintaining sensor performance.

[0035] The positioning method for yoke unit 2 and yoke unit 3 using positioning jig 110 will be described. Figure 15 is a front view of the assembly shown in Figure 12, and Figure 16 is an enlarged view of the area around positioning jig 110. The end shape of the recess 130 of the second engaging part of yoke unit 2 and the end shape of the recess 150 of the second engaging part of yoke unit 3 are positioned at the same location in the circumferential direction. The outer shape 153 of yoke unit 3 is smaller than the outer shape 133 of yoke unit 2, and the recess 150 of the second engaging part of yoke unit 3 is positioned inward from the recess 130 of the second engaging part of yoke unit 2. There are at least two recesses 130 of the second engaging part of yoke unit 2 and two recesses 150 of the second engaging part of yoke unit 3, and in a plane perpendicular to the axial direction, the angle θ around the center of the part connecting the center of the recess of each part to the center of the part and the center of adjacent recesses in the circumferential direction is all 180 degrees or less. This structure restricts the circumferential and radial movement of the pendulum 1 of yoke unit 3 relative to yoke unit 2.

[0036] The assembly accuracy of the pendulum 1 and yoke units 2 and 3 in this embodiment will be explained using Figures 4, 14, and 16. The difference between the diameter of the smallest inscribed circle 131 of the innermost end shape in the radial direction in the recess 130 of the second engagement part of yoke unit 2, or the diameter of the smallest inscribed circle 151 of the innermost end shape in the radial direction in the recess 150 of the second engagement part of yoke unit 3, and the diameter of the smallest inscribed circle 121 of the innermost end shape in the radial direction in the recess 120 of the first engagement part of the support part is smaller than the gap 101 between the torque cup and the pole piece or permanent magnet, or the gap 102 between the torque coil or torque cup and the yoke. The difference between the diameters of the smallest inscribed circles 131 and 151 in the second engagement parts of yoke units 2 and 3 and the smallest inscribed circle 121 in the recess of the support part is the dimension by which the pendulum 1 can move circumferentially and radially relative to the yoke units 2 and 3 during assembly, and represents the maximum amount of positional displacement caused by assembly. The fact that this displacement is smaller than gaps 101 and 102 suppresses contact between the torque coil and torque cup and surrounding components, contributing to a reduction in servo accelerometer malfunctions.

[0037] To suppress deformation of the support portion 10b and maintain sensor accuracy, it is preferable that the number of recesses 120 in the first engaging portion of the support portion be small and evenly distributed. The more recesses 120 there are in the first engaging portion, the smaller the volume of the support portion becomes, and the lower its rigidity becomes, making the support portion 10b more susceptible to deformation. By evenly distributing the recesses 120, the deformation of the support portion is dispersed, reducing the maximum deformation amount, which helps to suppress the failure of the support portion and the reduction of sensor performance due to deformation of the support portion.

[0038] As shown in Figure 9, it is preferable that the recess 120 of the first engaging portion of the support portion and the recess 130 of the second engaging portion of the yoke unit 2 are not located on the metal wire 24 in the circumferential direction. In the process of joining the metal wire 24, the positioning jig 110 is not placed around the joining portion of the metal wire 24, and the space above it is left open. Since the positioning jig 110 does not obstruct the device for joining the metal wire 24 from entering near the metal wire, there are fewer constraints on joining the metal wire 24, and good joining of the metal wire can be expected.

[0039] It is preferable that the recess 120 of the first engaging portion of the support portion is not located at the position of the fixing portion 10f of the support portion in the circumferential direction. During assembly, stress concentrates at the fixing portion 10f, so if a structure like the recess 120 is adjacent to it, the stress concentration there will increase, potentially increasing the risk of failure or deformation of the support portion 10b.

[0040] As shown in Figure 3, one of the recesses 120 of the first engaging portion of the support portion is located on the outer circumference of the fan-shaped portion 10g, to which the hinge 10c is connected and which has a larger volume than the other support portion 10b. Because the fan-shaped portion 10g has a larger volume compared to the other parts, it has high rigidity and deforms less even when subjected to force from the positioning jig. By placing the recess on the outer circumference of the fan-shaped portion 10g, deformation of the support portion 10b is suppressed, contributing to the maintenance of sensor performance.

[0041] The shape of the engagement portion should be such that the positioning jig 110 can be inserted into its recess. For example, it may be an arc shape, a rectangle shape, or a wedge shape. However, recesses with sharp angles tend to concentrate stress generated during assembly, which can easily cause component failure, so an arc shape is preferable for the recess to minimize stress concentration. In particular, the support portion 10b has a thin and narrow structure and is greatly affected by the stress received from the yoke, so it is preferable that the recess 110 of the support portion be arc-shaped.

[0042] Figures 17 and 18 show an example of the positional relationship between the first and second engaging parts. The components in Figure 17 correspond to the components in Figure 14, and the recess 120 of the first engaging part provided on the support and the recess 130 of the second engaging part provided on the yoke unit 2 partially overlap over a predetermined area in the axial direction of the torque coil. Similarly, the components in Figure 18 correspond to the components in Figure 16, and the recess 130 of the second engaging part provided on the yoke unit 2 and the recess 150 of the second engaging part provided on the yoke unit 3 partially overlap over a predetermined area in the axial direction of the torque coil. If misalignment occurs in any of the components during assembly, the first and second engaging parts will come into contact with the positioning jig 110, and the misalignment of each component will be stopped by the positioning jig 110. Since the positions of the first and second engaging parts align with the end face of the positioning jig 110, they may partially overlap over a predetermined area in the axial direction. The relationship of the engaging parts in this embodiment is not limited to cases where the engaging parts do not coincide in the axial direction, as shown in Figures 14 and 16, but also includes cases where a portion of the engaging parts overlaps in the axial direction over a predetermined area, as shown in Figures 17 and 18.

[0043] (Example 2) Figure 19 shows the configuration of one embodiment of a servo accelerometer, and is an exploded perspective view of the components. Figure 20 shows a cross-sectional view of the servo accelerometer cut through the center. The servo accelerometer is a device made up of stacked disc-shaped and cylindrical parts, and the central axes of these parts coincide. The end of the seal band 23 is in contact with the recess 15b on the outer circumference of the yoke 15, and in assembly, the seal band 23 is abutted against the recess 15b in the axial direction to determine its position. The yoke unit 2 and the yoke unit 3 also have through holes 140 and 160 of the second engaging part. Figure 21 shows the pendulum 1. The support part 10b has a recess 120 of the first engaging part on its inner circumference that corresponds to the through hole 140 of the second engaging part of the yoke unit 2 and the through hole 160 of the second engaging part of the yoke unit 3.

[0044] The assembly method of the pendulum 1, yoke unit 2, yoke unit 3, and seal band 23 will be explained. Figure 22 is a diagram showing each component and the positioning jig 110 unfolded in the axial direction. The positioning jig 110 is fixed to the yoke unit 2 by a mechanism (not shown). The side surface of the positioning jig 110 fits into the recess 120 of the first engaging portion of the support portion, restricting the radial and circumferential movement of the support portion 10b.

[0045] Figure 23 shows a perspective view of the assembly comprising the pendulum 1, the yoke unit 2, and the positioning jig 110. The positioning jig 110 is inserted from the rear side of the yoke unit 2 into the through hole 140 of the second engagement portion of the yoke unit 2. The pendulum 1 is fixed to the upper surface of the yoke unit 2 and the metal wire 24 is joined, while inserting the recess 120 of the first engagement portion of the support portion 10b into the positioning jig 110 which is exposed on the surface of the yoke unit 2.

[0046] Figure 24 shows a perspective view of the assembly in Figure 23 with the seal band 23 fixed to it. The seal band 23 is inserted around the outer circumference of the yoke unit and stops in the recess 15b of the yoke, determining its axial position. Figure 25 shows a perspective view of the assembly in Figure 24 with the yoke unit 3 fixed to it, and Figure 26 shows a front view of the yoke unit 3. The yoke unit 3 is inserted into the seal band 23 so that the positioning jig 110 is inserted into the through hole 160 of the second engagement part of the yoke unit 3, and the open end face of the yoke unit 3 is placed on the surface of the pendulum 1. The seal band is fixed while applying load from the outer circumference of the yoke units 2 and 3 so as to sandwich the pendulum. Then, the servo accelerometer is completed when the positioning jig 110 is removed from the assembly.

[0047] The positioning method for the pendulum 1 and the yoke unit 2 using the positioning jig 110 is described in detail. Figure 27 is a front view of Figure 23, and Figure 28 is an enlarged view of the area around the positioning jig 110 in Figure 27. The end shape of the recess 120 of the first engaging part of the support part coincides with or is close to the end shape of the through hole 140 of the second engaging part of the yoke unit 2 in the axial direction. There are at least two recesses 120 of the first engaging part of the support part and at least two through holes 140 of the second engaging part of the yoke unit 2, and in a plane perpendicular to the axial direction, the angle θ connecting the center of the engaging part of each part, the center of each part, and the center of the circumferentially adjacent engaging part is all 180 degrees or less. This structure restricts the radial and circumferential movement of the pendulum 1 relative to the yoke unit 2.

[0048] The diameter of the smallest circumscribed circle 141 of the outermost end shape in the radial direction in the through hole 140 of the second engagement portion of the yoke unit 2 is smaller than the diameter of the smallest circumscribed circle 122 of the outermost end shape in the radial direction in the recess 120 of the first engagement portion of the support portion. Because a gap is created between the support portion 10b and the positioning jig 110, the support portion 10b is less likely to receive radial force from the positioning jig 110. Creating a gap between the support portion 10b and the positioning jig 110 reduces deformation of the support portion 10b and contributes to maintaining sensor performance.

[0049] The positioning method for the yoke unit 3 will now be described. The seal band 23 is fixed in place, with its radial movement restricted by the shape of its inner circumference and the outer shape of the yoke unit 2. Similarly, the yoke unit 3 is fixed in place, with its radial movement restricted by the shape of the inner circumference of the seal band 23. Since the radial positioning of the yoke unit 2, yoke unit 3, and seal band does not involve the positioning jig 110 as in Embodiment 1, assembly errors originating from the jig do not occur, enabling more precise assembly in the radial direction. During assembly, the positioning jig 110 passes through the inside of the yoke unit 2 to determine the position of the support portion 10b, making it possible to fix the seal band 23 to the yoke unit 2 before fixing the yoke unit 3, thus enabling the aforementioned positioning method.

[0050] The yoke unit 3 has one through-hole 160 in the second engagement portion, into which a positioning jig 110 protruding from the yoke unit 2 is inserted to determine the circumferential position of the yoke unit 3. The through-hole 140 in the second engagement portion of the yoke unit 2 and the through-hole 160 in the second engagement portion of the yoke unit 3 overlap in the axial direction, ensuring an area for insertion of the positioning jig.

[0051] The assembly accuracy of the pendulum 1 and yoke unit 2 in this embodiment will be explained using Figures 4 and 28. The difference between the diameter of the smallest circumscribed circle 141 of the outermost end shape in the radial direction in the through hole 140 of the second engagement part of the yoke unit 2 and the smallest circumscribed circle 122 of the outermost end shape in the radial direction in the recess 120 of the first engagement part of the support part is smaller than the gap 101 between the torque cup and the pole piece or permanent magnet, or the gap 102 between the torque coil or torque cup and the yoke. The difference between the diameter of the smallest circumscribed circle 141 of the through hole of the yoke unit 2 and the diameter of the smallest inscribed circle 122 of the recess of the support part is the dimension by which the pendulum 1 can move circumferentially and radially relative to the yoke unit 2 during assembly, and represents the maximum amount of positional displacement caused by assembly. The fact that this amount of positional displacement is smaller than the gaps 101 and 102 suppresses contact between the torque coil or torque cup and surrounding parts, contributing to the reduction of malfunctions of the servo accelerometer.

[0052] (Example 3) Figure 29 shows the configuration of one embodiment of the servo accelerometer, and is an exploded perspective view of the components. Figure 30 shows a cross-sectional view of the servo accelerometer cut through the center. The servo accelerometer is a device made up of stacked disc-shaped and cylindrical parts, and the central axes of these parts coincide. In this embodiment, only the structure of the yoke unit 3 differs from that of Embodiment 2, and similarly, the assembly method of the yoke unit 3 and the seal band 23 also differs from that of Embodiment 2.

[0053] Figure 31 shows the assembly of the pendulum 1, yoke unit 2, yoke unit 3, and seal band 23, and Figure 32 shows the assembly unfolded in the axial direction. Figure 33 shows the rear view of yoke unit 3. The open end face side of yoke unit 3 that contacts the pendulum 1 has two or more through holes 160 for the second engaging portion. In the radial and circumferential directions, the through holes 160 for the second engaging portion are located in the same position as the recess 120 for the first engaging portion of the pendulum support and the through hole 140 for the second engaging portion of yoke unit 2. The through holes of yoke unit 2 and yoke unit 3 overlap in the axial direction, ensuring an area for inserting the positioning jig 110. The relationship between the recess 130 for the second engaging portion of the pendulum support and the through hole 140 for the second engaging portion of yoke unit 2 is the same as in Embodiment 2.

[0054] A method for positioning the yoke unit 3 using a positioning jig 110 will be described. Figure 34 is a front view of the assembly shown in Figure 31 with the circular yoke 18 removed, showing the through hole 160 of the second engagement part inside the yoke unit 3 and the positioning jig 110 exposed on the front side. Figure 35 is an enlarged view of the area around the positioning jig 110 in Figure 34, showing the through hole 140 of the second engagement part of the yoke unit 2 and the positioning jig 110 inside the through hole 160 of the second engagement part. The end shape of the through hole 160 of the second engagement part of the yoke unit 3 coincides with or is close to the end shape of the through hole 140 of the second engagement part of the yoke unit 3 in the axial direction. This ensures an area into which the positioning jig 110 can be inserted, and restricts the movement of the yoke unit 3 in the circumferential and radial directions.

[0055] As shown in Figure 32, there are no recesses on the outer circumference of yoke unit 2 and yoke unit 3. Therefore, as shown in Figure 30, there is no large gap between the inner circumference of the seal band 23 and these assemblies. Welding or adhesive is used to fix the seal band 23 to yoke units 2 and 3, but if there are recesses on the outer circumference of yoke units 2 and 3 as in Example 1, the seal band 23 and yoke units 2 and 3 will not be in close contact at those locations. The stress that yoke units 2 and 3 receive from the seal band 23 will be uneven in the circumferential direction, which will apply an uneven force in the circumferential direction to the pendulum support part 10b fixed by yoke units 2 and 3, and may cause deformation of the support part 10b. If the seal band 23 is fixed to the entire circumferential surface of yoke units 2 and 3, the force that yoke units 2 and 3 apply to the support part 10b will be more uniform, and a decrease in sensor performance can be suppressed. [Explanation of Symbols]

[0056] 1 pendulum 2, 3 yoke units 10. Base of the pendulum 10a Pendulum weight 10b Support part of the pendulum 10c Pendulum hinge Thin film electrodes of a 10d pendulum 10e Thin film wiring formed on the surface of hinges, supports, and weights. 10f Fixing part of the support that is fixed by the yoke 10g Pendulum Support Section (Fan-shaped part) 11, 12 Torca Coil 13, 14 Torka Cup 15th, 16th York 15a, 16a Pendulum fixing part in yoke 15b Recess for positioning the seal band in the yoke Electrode surfaces of 15e and 16e yokes 15g yoke protrusion 17, 18 circular yokes 19, 20 pole pieces 21, 22 Permanent magnets 23 Seal Bands 24 metal wires 24a First connection where the metal wire and thin film wiring are connected 24b Second connection where the metal wire and the end face of the terminal are connected. 30 Acceleration detection axes 100 Magnetic gap 101 Gap between the Torca cup and the pole piece or permanent magnet 102 Gap between the Torca coil or Torca cup and the yoke 103 Forces acting on the support structure 110 Positioning jig 120 Recess in the first engagement part of the pendulum support 121 The smallest inscribed circle of the radially innermost end shape in the recess of the first engagement part of the pendulum support. 122 The smallest circumscribed circle of the radially outermost end shape in the recess of the first engagement part of the pendulum support. 123 Outer shape of the pendulum support 124 Internal shape of the pendulum support 130 Recess in the second engagement portion of yoke unit 2 131 Minimum inscribed circle of the radially innermost end shape in the recess of the second engagement portion of yoke unit 2 133 Outer shape of yoke unit 2 140 Through hole of the second engaging portion of yoke unit 2 141 Minimum inscribed circle of the radially innermost end shape in the through hole of the second engagement portion of yoke unit 2 142 Minimum circumscribed circle of the radially outermost end shape in the through hole of the second engagement portion of yoke unit 2 150 Recess in the second engaging portion of yoke unit 3 151 Minimum inscribed circle of the radially innermost end shape in the recess of the second engagement portion of yoke unit 3 153 Outer shape of yoke unit 3 160 Through hole of the second engaging portion of yoke unit 3 161 The smallest inscribed circle of the radially innermost end shape in the through hole of the second engagement portion of the yoke unit 3 162 Minimum circumscribed circle of the radially outermost end shape in the through hole of the second engagement portion of yoke unit 3

Claims

1. A servo accelerometer in which the inertial force generated in a pendulum, the current flowing through the torque coil wrapped around the torque cup, and the Lorentz force generated by the magnetic field in a yoke unit composed of a yoke, pole piece, and permanent magnet are balanced, The pendulum mentioned earlier is A thin film wiring is provided on the surface, and a support portion is fixed to the yoke, The support portion has a weight portion that is suspended by a hinge and is displaceable, A servo accelerometer characterized in that a first engaging portion provided on the outer circumference of the support portion and a second engaging portion provided on the outer circumference of the yoke unit are arranged at the same position in the circumferential direction of the torque coil.

2. A servo accelerometer in which the inertial force generated in a pendulum, the current flowing through the torque coil wrapped around the torque cup, and the Lorentz force generated by the magnetic field in a yoke unit composed of a yoke, pole piece, and permanent magnet are balanced, The pendulum mentioned earlier is A thin film wiring is provided on the surface, and a support portion is fixed to the yoke, The support portion has a weight portion that is suspended by a hinge and is displaceable, A servo accelerometer characterized in that a first engaging portion provided on the inner circumference of the support portion and a second engaging portion provided on the yoke unit are arranged at the same position in the circumferential direction of the torque coil.

3. A servo accelerometer in which the inertial force generated in a pendulum, the current flowing through the torque coil wrapped around the torque cup, and the Lorentz force generated by the magnetic field in a yoke unit composed of a yoke, pole piece, and permanent magnet are balanced, The pendulum mentioned earlier is A thin film wiring is provided on the surface, and a support portion is fixed to the yoke, The support portion has a weight portion that is suspended by a hinge and is displaceable, A servo accelerometer characterized in that a first engaging portion provided on the support portion and a second engaging portion provided on the yoke unit partially overlap over a predetermined range in the axial direction of the torque coil.

4. The outer shape of the support portion is cylindrical, The outer shape of the yoke unit is cylindrical, At least two of the first engaging portions are arranged on the support portion, The servo accelerometer according to any one of claims 1 to 3, characterized in that at least two of the second engaging portions are arranged on the yoke unit.

5. In a plane perpendicular to the axial direction of the torque coil, all angles around the center of the support portion formed by connecting the center of one of the first engagement portions, the center of the support portion, and the centers of the first engagement portions adjacent to the first engagement portion in the circumferential direction are 180 degrees or less. The servo accelerometer according to claim 4, characterized in that, in a plane perpendicular to the axial direction of the torque coil, all angles around the center of the support portion formed by connecting the center of one of the second engagement portions, the center of the yoke unit, and the center of the second engagement portion adjacent to the one of the second engagement portions in the circumferential direction are 180 degrees or less.

6. In the first engagement portion, the minimum inscribed circle of the innermost end shape in the radial direction of the torque coil is smaller than the minimum inscribed circle of the innermost end shape in the radial direction of the second engagement portion. The servo accelerometer according to claim 4, characterized in that the difference between the diameter of the smallest inscribed circle of the innermost end shape in the radial direction in the first engagement portion and the diameter of the smallest inscribed circle of the innermost end shape in the radial direction in the second engagement portion is smaller than the gap between the torquer cup and the pole piece or the permanent magnet, and the gap between the torquer coil or the torquer cup and the yoke.

7. In the second engagement portion, the minimum circumscribed circle of the outermost end shape in the radial direction of the torque coil is smaller than the minimum circumscribed circle of the outermost end shape in the radial direction of the first engagement portion. The servo accelerometer according to claim 4, characterized in that the difference between the diameter of the smallest circumscribed circle of the outermost end shape in the radial direction in the second engagement portion and the diameter of the smallest circumscribed circle of the outermost end shape in the radial direction in the first engagement portion is smaller than the gap between the torquer cup and the pole piece or the permanent magnet, and the gap between the torquer coil or the torquer cup and the yoke.

8. Having a metal wire connected to the thin film wiring, A servo accelerometer according to any one of claims 1 to 3, characterized in that the first engaging portion is not positioned at the location of the metal wire in the circumferential direction of the torque coil.

9. The support portion has a fan-shaped portion, The aforementioned fan-shaped portion suspends the hinge, A servo accelerometer according to any one of claims 1 to 3, characterized in that the first engaging portion is arranged in the fan-shaped portion.

10. The support portion has a fixing portion that contacts and is fixed to the yoke, A servo accelerometer according to any one of claims 1 to 3, characterized in that the first engaging portion is not positioned at the location of the fixed portion in the circumferential direction of the torque coil.

11. Having two of the aforementioned yokes, The two yokes are fixed to the seal band, The servo accelerometer according to claim 2, characterized in that the end of the seal band is in contact with one of the yokes in the axial direction of the servo accelerometer, and the outer shape of the other yoke is in contact with the shape of the inner circumference of the seal band.

12. The first engaging portion is characterized by having an arc shape. A servo accelerometer according to any one of claims 1 to 3.

Images