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CN-116243017-B - Acceleration sensor

CN116243017BCN 116243017 BCN116243017 BCN 116243017BCN-116243017-B

Abstract

The invention relates to an acceleration sensor having at least one piezoelectric element, at least one test block, and a base body, the acceleration sensor being arranged in a rectangular coordinate system having three axes, one of which is a vertical axis, the base body having a tangential side surface and a normal side surface, the tangential side surface being arranged tangentially with respect to the vertical axis and the normal side surface being arranged normally with respect to the vertical axis, the acceleration sensor having exactly three piezoelectric elements and exactly three test blocks, exactly one piezoelectric element being fastened to each of the three tangential side surfaces, exactly one test block being fastened to each of the three piezoelectric elements and exerting a shear force on the piezoelectric elements proportional to the acceleration upon acceleration, each of the three piezoelectric elements having a high sensitivity to a shear force exerted by the test block fastened thereto along a main tangential axis, the main tangential axis being a different one of the three axes for each of the three piezoelectric elements.

Inventors

  • M. Lavlanci
  • T. Fromenville
  • D. WEBER

Assignees

  • 基斯特勒控股公司

Dates

Publication Date
20260508
Application Date
20211102
Priority Date
20201102

Claims (14)

  1. 1. An acceleration sensor (1) having at least one piezoelectric element (10, 10 ''), at least one test mass (11, 11 ''), and a base body (12); the acceleration sensor (1) is arranged in a rectangular coordinate system having three axes (x, y, z), wherein the three axes (x, y, z) comprise a transverse axis (x), a longitudinal axis (y) and a vertical axis (z); the base body (12) has a tangential side (12.1,12.2,12.3,12.4) and a normal side (12.6,12.7), the tangential side (12.1,12.2,12.3,12.4) being arranged tangentially with respect to the vertical axis (z) and the normal side (12.6,12.7) being arranged normally with respect to the vertical axis (z); It is characterized in that the method comprises the steps of, -Fastening exactly one piezoelectric element (10, 10 '') on at least one tangential side (12.1, 12.2, 12.3); -fastening exactly one test block (11, 11',11 ") on the piezoelectric element (10, 10', 10") and exerting on the piezoelectric element (10, 10',10 ") upon acceleration a shearing force proportional to the acceleration, said shearing forces acting together along one of the three axes (x, y, z) as main tangential axis (h); The piezoelectric element (10, 10 '') has end faces (110, 120), each end face (110, 120) lying in a plane spanned by the primary tangential axis (h) and a secondary tangential axis (n), in which plane the secondary tangential axis (n) is perpendicular to the primary tangential axis (h) and has a normal axis (a) normal to the plane; -said piezoelectric element (10, 10',10 ") generates a piezoelectric charge on said end face (110, 120) under the effect of a shearing force along said main tangential axis (h); -a test block (11) fastened to the piezoelectric element (10, 10',10 ") exerting a shearing force on the piezoelectric element (10, 10', 10") along a secondary tangential axis (n) during acceleration, the piezoelectric element (10, 10',10 ") generating a piezoelectrically disturbing charge on the end face (110, 120) under the action of the shearing force along the secondary tangential axis (n); the piezoelectric element (10, 10 '') has at least one end face (110, 120) with at least one conductive end face coating (111, 121), the conductive end face coating (111, 121) intercepting piezoelectric charges for shear forces along the primary tangential axis (h), and the conductive end face coating (111, 121) intercepting piezoelectric interference charges for shear forces along the secondary tangential axis (n); the piezoelectric element (10, 10 '') has a side (130, 140,150, 160) parallel to the normal axis (a); -a test block (11, 11',11 ") fastened to the piezoelectric element (10, 10', 10") exerting a normal force on the piezoelectric element (10, 10',10 ") along the normal axis (a) during acceleration, proportional to the acceleration, the piezoelectric element (10, 10', 10") generating a piezoelectric disturbance charge on the end face (110, 120) under the effect of the normal force along the normal axis (a); The piezoelectric element (10, 10 '') has at least one side (130, 140,150, 160) with at least one electrically conductive side coating (131,133,141,151,161) in a region, and the electrically conductive side coating (131,133,141,151,161) intercepts piezoelectrically disturbing charges for normal forces along the normal axis (a).
  2. 2. Acceleration sensor (1) according to claim 1, characterized in, that, The piezoelectric element (10, 10 '') has a high sensitivity to shear forces along the main tangential axis (h) exerted by a test block (11, 11 '') fastened thereto; the piezoelectric element (10, 10 '') has a low sensitivity to shear forces along the secondary tangential axis (n) exerted by a test block (11, 11 '') fastened thereto, and The piezoelectric element (10, 10 '') has a low sensitivity to a normal force along the normal axis (a) exerted by a test block (11, 11 '') fastened thereto.
  3. 3. Acceleration sensor (1) according to claim 1, characterized in, that, The piezoelectric element (10) has a high sensitivity to shear forces along a longitudinal axis (y) as a primary tangential axis (h), a low sensitivity to shear forces along a vertical axis (z) as a secondary tangential axis (n), and a low sensitivity to normal forces along a lateral axis (x) as a normal axis (a); and/or the piezoelectric element (10') has a high sensitivity to shear forces along a transverse axis (x) as a primary tangential axis (h), a low sensitivity to shear forces along a vertical axis (z) as a secondary tangential axis (n), and a low sensitivity to normal forces along a longitudinal axis (y) as a normal axis (a); and/or the piezoelectric element (10 '') has a high sensitivity to shear forces along a vertical axis (z) as a primary tangential axis (h), a low sensitivity to shear forces along a longitudinal axis (y) as a secondary tangential axis (n), and a low sensitivity to normal forces along a transverse axis (x) as a normal axis (a).
  4. 4. Acceleration sensor (1) according to claim 1, characterized in, that the piezoelectric element (10, 10',10 ") generates at least 5 times more piezoelectric charge per unit force with a high sensitivity for shear forces along the main tangential axis (h) than with a low sensitivity for shear forces along the secondary tangential axis (n) or than with a low sensitivity for normal forces along the normal axis (a).
  5. 5. Acceleration sensor (1) according to claim 1, characterized in, that for the piezoelectric element (10, 10',10 "), the conductive end-face coating (111, 121) and the conductive side-face coating (131,133,141,151,161) form a continuous conductive coating (101, 102) and that the piezoelectric disturbance charge intercepted for shear forces along the secondary tangential axis (n) has a polarity opposite to that intercepted for normal forces along the normal axis (a).
  6. 6. Acceleration sensor (1) according to claim 5, characterized in, that the conductive side coating (131,133,141,151,161) is adjustable in size for the piezoelectric element (10, 10',10 "), the conductive side coating (131,133,141,151,161) being so sized that the continuous conductive coating (101, 102) is largely as much as the piezoelectric interference charge intercepted by the shear force along the secondary tangential axis (n) is as the piezoelectric interference charge intercepted by the normal force along the normal axis (a).
  7. 7. Acceleration sensor (1) according to claim 5, characterized in that for the piezoelectric element (10, 10',10 "), the side surfaces (130, 140,150, 160) comprise a first side surface (130), which first side surface (130) is normal to a minor tangential axis (n) of the piezoelectric element (10, 10', 10"), the first side surface (130) has a first conductive side coating (131) and a further first conductive side coating (133), the ratio of the size of the first conductive side coating (131) to the size of the further first conductive side coating (133) is adjustable, the ratio of the size of the first conductive side coating (131) to the size of the further first conductive side coating (133) being adjusted such that the piezoelectric charge of the continuous conductive coating (101, 102) is as much as the same extent as the piezoelectric charge of the shear force along the minor tangential axis (n).
  8. 8. Acceleration sensor (1) according to claim 7, characterized in that the acceleration sensor (1) has a first piezoelectric element conductor (13.1,13.1 ',13.1 ") and a second piezoelectric element conductor (13.2,13.2', 13.2"), that for the piezoelectric element (10, 10',10 "), the first conductive side coating (131) is connected in a material-fit to the first piezoelectric element conductor (13.1,13.1', 13.1"), that for the piezoelectric element (10, 10',10 "), the further first conductive side coating (133) is connected in a material-fit to the second piezoelectric element conductor (13.2,13.2', 13.2"), that the first piezoelectric element conductor (13.1,13.1 ',13.1 ") derives a piezoelectric charge from a first continuous conductive coating (101) as a first acceleration signal (S1), and that the second piezoelectric element conductor (13.2,13.2', 13.2") derives a piezoelectric charge from a second continuous conductive coating (102) as a second acceleration signal (S2).
  9. 9. Acceleration sensor (1) according to any one of the claims 1-8, characterized in that for the piezoelectric element (10, 10 ''), the conductive end-face coating (111, 121) is placed material-fittingly on the end-face (110, 120) and closes off tiny holes in the end-face (110, 120), the conductive side-face coating (131,133,141,151,161) is placed material-fittingly on the side-face (130, 140,150, 160) and closes off tiny holes in the side-face (130, 140,150, 160), and by closing off tiny holes the piezoelectric element (10, 10 '') no longer needs mechanical pretension.
  10. 10. Acceleration sensor (1) according to any one of the claims 1-8, characterized in that the end face (110, 120) of at least one piezoelectric element (10, 10',10 ") comprises a first end face (110) and a second end face (120), the first end face (110) and the second end face (120) being oriented in opposite directions with respect to a normal axis (a) of the piezoelectric element (10, 10', 10"), the first end face (110) having a first conductive end face coating (111), the second end face (120) having a second conductive end face coating (121), the side faces (130, 140,150, 160) comprising a first side face (130), the first side face (130) being normal to a secondary tangential axis (n) of the piezoelectric element (10, 10',10 "), the first side face (130) having a first conductive side face coating (131) and a further first conductive side face coating (133), the first conductive end face coating (111) and the first conductive side face coating (131) forming a first continuous end face coating (101) and the second conductive side face coating (102).
  11. 11. The acceleration sensor (1) according to claim 10, characterized in, that the sides (130, 140,150, 160) of the piezoelectric element (10, 10',10 ") comprise at least one second side (140) and at least one third side (150), the second side (140) and the third side (150) being normal to the main tangential axis (h) of the piezoelectric element (10, 10', 10"), the second side (140) having a second conductive side coating (141), the third side (150) having a third conductive side coating (151), and the second conductive side coating (141) and the third conductive side coating (151) being part of the first continuous conductive coating (101) or being part of the second continuous conductive coating (102).
  12. 12. The acceleration sensor (1) according to claim 10, characterized in, that the side face (130, 140,150, 160) of the piezoelectric element (10, 10',10 ") comprises at least one second side face (140) and at least one third side face (150), the second side face (140) and the third side face (150) being normal to the main tangential axis (h) of the piezoelectric element (10, 10', 10"), the second side face (140) having a second conductive side coating (141), the third side face (150) having a third conductive side coating (151), the third conductive side coating (151) being part of the first continuous conductive coating (101) and the second conductive side coating (141) being part of the second continuous conductive coating (102).
  13. 13. The acceleration sensor (1) according to claim 10, characterized in, that the side faces (130, 140,150, 160) of the piezoelectric element (10, 10',10 ") comprise at least one second side face (140) and at least one fourth side face (160), the second side face (140) being normal to the main tangential axis (h) of the piezoelectric element (10, 10', 10"), the fourth side face (160) being normal to the secondary tangential axis (n) of the piezoelectric element (10, 10',10 "), the second side face (140) having a second conductive side face coating (141), the fourth side face (160) having a fourth conductive side face coating (161), and the second conductive side face coating (141) and the fourth conductive side face coating (161) being part of the first continuous conductive coating (101) or part of the second continuous conductive coating (102).
  14. 14. The acceleration sensor (1) according to claim 10, characterized in, that the sides (130, 140,150, 160) of the piezoelectric element (10, 10',10 ") comprise at least one third side (150) and at least one fourth side (160), the third side (150) being normal to the main tangential axis (h) of the piezoelectric element (10, 10', 10"), the fourth side (160) being normal to the secondary tangential axis (n) of the piezoelectric element (10, 10',10 "), the third side (150) having a third conductive side coating (151), the fourth side (160) having a fourth conductive side coating (161), the third conductive side coating (151) being part of the first continuous conductive coating (101) and the fourth conductive side coating (161) being part of the second continuous conductive coating (102).

Description

Acceleration sensor The application is a divisional application of the application application of which the Chinese application date of the Kidner control company of the applicant is 2021, 11 and 2, the application name is an acceleration sensor and the Chinese national application number is 202111287693.3. Technical Field The present invention relates to an acceleration sensor. Background In many very different applications, such as robots, power generation, transportation, etc., it is necessary to detect the acceleration of a physical object. Here, the impact acting on the physical object and the vibration of the physical object are detected as accelerations. Acceleration is given as a multiple of gravitational acceleration g=9.81 msec-2. In the measurement range of 2Hz to 10kHz, the typical order of magnitude of the detected acceleration is +/-500g. In order to detect acceleration, an acceleration sensor is fastened to a physical object. Patent document CH399021A1 shows one such acceleration sensor, which has a test mass, a piezoelectric system and a base body. In order to prevent harmful environmental influences, the acceleration sensor has a housing in which the test block, the piezo system and the base body are arranged. The acceleration sensor is fastened to the physical object through the housing. Upon acceleration, the test mass exerts a force on the piezoelectric system proportional to its acceleration. The piezoelectric system has a plurality of flat disks made of piezoelectric material with high sensitivity to piezoelectric longitudinal effects. Under the force, the piezoelectric material generates a piezoelectric charge, the amount of which is proportional to the magnitude of the force. Under the piezoelectric longitudinal effect, a piezoelectric charge is generated on the same end face of the disk, on which the force as normal force also acts. Each disk has two end faces on which piezoelectric charges of opposite polarity are generated. The piezoelectric system also has thin electrodes made of conductive material to intercept piezoelectric charges from the two end faces. Each electrode has a face sized. The electrode rests directly and completely against the end face via this surface. Furthermore, the piezo system is mechanically preloaded between the test block and the base body by a preload sleeve. By such mechanical pretensioning, the tiny holes between the end face and the electrode are closed, so that all the generated piezoelectric charges can be intercepted, which is important for the linearity of the acceleration sensor, which is the ratio of the amount of piezoelectric charges to the magnitude of the force. The piezoelectric charge may be electrically derived as an acceleration signal. The electrically derived acceleration signal may be electrically converted in a converter unit. Patent document DE69405962T2 also describes an acceleration sensor with a test block and a piezoelectric system on a printed circuit board. The acceleration sensor detects acceleration as a shear force along an axis according to a lateral shear effect. The piezoelectric system is disposed between the test block and the printed circuit board. The converter unit is located on a printed circuit board. The piezoelectric system of patent document CH399021A1 is only sensitive to normal forces along the axis. The piezoelectric system of DE69405962T2 is then only sensitive to shear forces along the axis. However, an acceleration sensor capable of detecting accelerations along a plurality of axes of a rectangular coordinate system at the same time is desired. Patent document RU1792537C1 discloses an acceleration sensor that can detect acceleration in three physical dimensions. A piezoelectric system having six flat disks made of piezoelectric material and six test pieces was assembled on a cube-shaped base having six surfaces. Each two surfaces are oriented normally with respect to one of three mutually perpendicular axes, hereinafter referred to as normal axes. On each of the six surfaces, a flat disc is disposed between the surface and the test block. The disks are mechanically preloaded against the base body by an external preloading housing. Thus, the piezoelectric system has a pair of disks for each of the three normal axes. These discs have a high sensitivity to lateral shearing effects. In the case of a transverse shearing effect, a pinch point charge is generated on the same end face of the disk as the shear force acts tangentially to the normal axis, which axis is hereinafter referred to as the primary tangential axis. The piezoelectric system also has electrodes made of conductive material for intercepting piezoelectric charges from the end faces of the disks. According to document RU1792537C1, the piezoelectric system has, for each of the three normal axes, a pair of discs made of piezoelectric material, which have a high sensitivity to shear forces along the main tangential axis. Unfortunately, it is unavo