JPS63311173A - Mounting apparatus of sensor assembly of accelerometer - Google Patents

Abstract

PURPOSE:To improve the vibration resisting characteristic of an accelerometer, by separately providing a fixing ring for attaching a sensor assembly to a casing lower than a flange for attaching the casing to a mounting stage. CONSTITUTION:An annular groove 30 is formed at the bottom part of the inner surface wall of a cylindrical casing 18. A fixing ring 32 is attached at a part close to the lower end of a lower magnet structure 24 of a cylindrical sensor assembly 20 so that the ring 32 is positioned slightly higher than the groove 30. The ring 32 is bridged on an gap between the sensor assembly 20 and the casing 18. Thus, the assembly 20 is mounted so that the upper part of the assembly is not restrained with the casing 18 and the assembly 20 can be supported at its lower part. The casing 18 is not formed as a cylindrical container having a bottom plate 34, but the cylindrical part and the bottom plate 34 are separately constituted. After the annular groove 30 is formed at one end of the cylindrical part, the bottom plate 34 is coupled by, e.g., laser welding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mounting device for a sensor assembly of an accelerometer, more specifically a capacitance pick consisting of a magnetic device with a flapper in its gauging or housing.
The present invention relates to a device for mounting a sensor assembly of an accelerometer using an off-state.

[Background of the Invention] Accelerometers that are fixed to objects whose acceleration is to be detected or measured generally include a magnet unit consisting of a pair of magnet structures as a sensor assembly in a cylindrical gauging or housing, and a sensor assembly between the magnet units. Flexible flapper
That is, the flapper is mounted so that it can be bent, coils are arranged on both sides of the flapper, and a permanent magnet is surrounded by the coils. When an object equipped with this is accelerated, the flapper is moved relative to the magnet unit in an attempt to keep it stationary in space, and this movement forms a pair of capacitors between the flapper and the magnet unit, and the movement of the flapper causes a pair of capacitors to be formed between the flapper and the magnet unit. The increase in capacitance of one capacitor and the decrease in capacitance of the other capacitor are modulated in conjunction with an accompanying balancing circuit into a direct current proportional to acceleration, which is fed back to said coil to restore the flapper and its Measure acceleration by detecting direct current.

This type of accelerometer is subject to significant thermal stress between its components due to the differences in thermal expansion coefficients due to the differences in the materials of the components of the sensor assembly assembled and housed within the gauging device when the ambient temperature changes drastically during use. occurs, which leads to measurement errors. For this reason, these components are manufactured with extreme precision, and various proposals have been made to prevent the occurrence of the above-mentioned thermal stress as much as possible.

By the way, when attaching the sensor assembly, which has been carefully considered for thermal stress, to the case, a gap is created between the inner wall of the flanged cylindrical casing and the outside of the sensor part, and electrical insulation is ensured. Attach an annular spacer made of material above the sensor assembly and fix it to the casing, and use a suitable tightening means such as a screw in the opening of the gauging flange. I try to hang it up.

However, according to the conventional mounting method described above, when the pedestal is exposed to an environment where it is subject to severe temperature changes ranging from high to low temperatures, the mounting is difficult due to the material constituting the pedestal and the accelerometer sensor assembly. between the case that houses the
Thermal stresses due to differences in thermal expansion coefficients were generated, which also subtly acted on each component of the sensor assembly within the casing, affecting the operation of the accelerometer.

[Objective of the Invention = 4- Considering the above problems, the main purpose of the present invention is to attach the sensor assembly, which is the heart of the accelerometer, to the casing so that external thermal stress is not transmitted to the sensor assembly. The objective is to provide a mounting device that can

An object of the present invention is to mount the sensor assembly of an accelerometer in its casing by extremely simple means, and to improve the vibration resistance characteristics of the accelerometer to a greater extent than those of the prior art. The goal is to provide equipment.

[Structure of the Invention] Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, the first embodiment includes a flange 14 at the top for mounting the accelerometer 10 on a stand 12, and a cylindrical hollow gauging 18 and a sensor assembly about the longitudinal central axis 16. It consists of 20 solid bodies.

Since the sensor assembly 20 is known per se, only a general outline thereof will be given for the sake of brevity. It consists of a cylindrical lower magnet structure 22, a lower magnet structure 24, and a disc-shaped intermediate structure 26 including a flapper arranged between the side structures, these structures 22, 24, 26.
are integrated with a belt-shaped central ring 28 to form a sensor assembly 20.
It's Nishide.

The cylindrical inner circumferential wall of the casing 18 that houses the generally cylindrical sensor assembly 20
Its diameter is larger than that of the outer peripheral wall, and a desired gap is provided between the two.

According to a first embodiment of the present invention, as shown in FIG. A fixing ring 32 is mounted proximate the lower end of the magnet structure 24 and somewhat above the groove 30, and the ring 32 is attached to the sensor assembly 20 and the casing 18.
The sensor assembly 20 is mounted such that the upper part of the sensor assembly 20 is not constrained to the casing 18 but can be supported at its lower part. In addition,
The inner and outer circumferential surfaces of the fixing ring 32 are joined to the outer circumferential surface of the opposing lower magnet structure 24 and the inner circumferential surface of the casing 18 .

Considering manufacturing issues, the gauging 18 is installed on the bottom plate 34.
Instead of forming a cylindrical container with a cylindrical container, the cylindrical portion and the bottom plate 34 may be constructed separately, and after forming an annular eraser 30 at one end of the cylindrical portion, the bottom plate 34 may be bonded by a suitable bonding means, such as laser welding. Alternatively, they can be bonded by using an adhesive or the like.

In the second embodiment of the present invention, as shown in FIG. 2, the flange 54 to be attached to the base 12 is constructed separately from the cylindrical casing 58, and the casing 58 is mounted on the flange 54. A circular opening 60 is formed in order to insert the flange 54, and an annular groove 30 is formed on the inner peripheral edge of the flange 54.
is formed.

A fixing ring 32 is fitted to the upper end of the sensor assembly 20 in the same manner as in the prior art, and the fixing ring 32 is fitted into the casing 58.
The flange 54 supports the upper end of the casing 58.
The upper end of the gauging 58 which supported the sensor assembly 20 with the fixing ring 32 is inserted into the opening 60 of the
The lower edge 62 of the annular stopper 30 of the seven flange 54 is connected to the casing 58 by suitable means such as laser welding or adhesive so as to be located in the hollow portion.

[Operations and Effects of the Invention] According to the first embodiment of the invention, the sensor assembly 20
Since the fixing ring 32 for attaching the casing 18 to the casing 18 is spaced below the flange 14 for attaching the casing 18 to the base 12, the fixing ring 32 is installed between the base 12 and the flange 14. The thermal stress that occurs is not directly transferred to the sensor assembly 20, but is absorbed by the cylindrical sidewall of the gauging 18, as shown in FIG. Furthermore, as shown in FIG. 4, the 7tIJ30 provided at the lower part of the casing 18 reduces the wall thickness of the casing 18 in this area, which helps absorb deformation of the casing 18 due to thermal stress. It is something.

Next, in a second embodiment, the sensor assembly 20 is supported so as to be suspended on the upper end of the gauging 58 by a retaining ring 32, or the attachment occurs between the base 12 and the flange 14. Even if the thermal stress is transmitted to the casing 18 through the lower edge 62 of the annular extinguisher 30 of the flange 54, the side wall portion supporting the fixing ring 32 of the gauging 18 has an annular groove as shown in FIG. It is absorbed by deformation in 30 cavities.

In addition, in the second embodiment, although it has been described that the flange 54 is configured separately from the casing 58, 71!28
Depending on the shape of the flange 54 and casing 58
and can be made into an integral structure.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view for explaining a first embodiment of a mounting device for an accelerometer sensor assembly according to the present invention, FIG. 2 is a schematic cross-sectional view for explaining a second embodiment thereof, and FIG. 3 and 4 are schematic diagrams illustrating the thermal stress absorption effect of the first embodiment, and FIG. 5 is a schematic diagram illustrating the thermal stress absorption effect of the second embodiment. The main reference numbers in the drawings are as follows. 10... Accelerometer 12... Mounting on stand 14.54... Flange 18.58... Gauging 20... Sensor assembly 30 ......Annular pickle 32...Fixing ring

Claims (1)

[Scope of Claims] 1. An accelerometer sensor assembly comprising a pair of magnet structures and an intermediate structure including a flapper disposed between the two magnet structures, and a mounting base for accommodating the assembly. a hollow cylindrical casing having a flange at the top to be attached to the casing;
The sensor assembly is mounted on the casing by providing an annular groove in the casing and disposing a fixing ring between the sensor assembly and an inner peripheral wall of the casing in proximity to the groove. A mounting device for an accelerometer sensor assembly comprising: 2. The device according to claim 1, wherein the annular groove is provided in the inner circumferential wall of the lower part of the casing. 3. The device according to claim 1, wherein the annular groove is provided on the inner circumferential wall of the flange at the upper part of the casing.