acceleration sensor

Abstract

The invention relates to an acceleration sensor having at least one piezoelectric element, at least one test mass, and a base body; the acceleration sensor is arranged in an orthogonal coordinate system having three axes, one of the three axes being a vertical axis; the base body has tangential sides and normal sides, the tangential sides being arranged tangentially with respect to the vertical axis, the normal sides being arranged normally with respect to the vertical axis; the acceleration sensor has exactly three piezoelectric elements and exactly three test masses; exactly one piezoelectric element is fastened on each of the three tangential sides; exactly one test mass is fastened on each of the three piezoelectric elements and exerts a shear force on the piezoelectric element that is proportional to the acceleration upon acceleration; each of the three piezoelectric elements has a high sensitivity to a shear force along a main tangential axis exerted by the test mass fastened thereto, the main tangential axis being a different one of the three axes for each of the three piezoelectric elements.

Description

[0001] This application is a divisional application of the Chinese application filed by the applicant, Kistler Holding, on November 2, 2021, entitled "Acceleration Sensor," with Chinese national application number 202111287693.3. Technical Field

[0002] This invention relates to an acceleration sensor. Background Technology

[0003] In many different applications, such as robotics, power generation, and transportation, it is necessary to detect the acceleration of physical objects. Here, we are detecting the impacts acting on the physical object and the vibrations of the object as acceleration. Acceleration is given as a multiple of the gravitational acceleration g = 9.81 msec⁻². In the measurement range of 2 Hz to 10 kHz, the typical order of magnitude of the detected acceleration is + / - 500 g. To detect acceleration, an accelerometer is fixed to the physical object.

[0004] Patent document CH399021A1 discloses an accelerometer comprising a test block, a piezoelectric system, and a substrate. To prevent harmful environmental impacts, the accelerometer has a housing in which the test block, piezoelectric system, and substrate are arranged. The accelerometer is secured to a physical object via the housing. During acceleration, the test block applies a force proportional to its acceleration to the piezoelectric system. The piezoelectric system has multiple flat disks made of piezoelectric material, highly sensitive to the longitudinal piezoelectric effect. Under the force, the piezoelectric material generates piezoelectric charges, the amount of which is proportional to the magnitude of the force. Under the longitudinal piezoelectric effect, piezoelectric charges are generated on the same end faces of the disks, where the force, as a normal force, also acts. Each disk has two end faces on which piezoelectric charges of opposite polarities are generated. The piezoelectric system also has thin electrodes made of conductive material to capture piezoelectric charges from the two end faces. Each electrode has a surface the size of one end face. The electrode rests directly and entirely against the end face through this surface. Furthermore, the piezoelectric system is mechanically pre-tightened between the test block and the substrate via a pre-tightening sleeve. This mechanical pre-tightening closes the tiny orifice between the end face and the electrode, thereby intercepting all generated piezoelectric charges. This is crucial for the linearity of the accelerometer, which is the ratio of the amount of piezoelectric charge to the magnitude of the force. The piezoelectric charges can be electrically extracted as an acceleration signal. The electrically extracted acceleration signal can then be electrically converted in the converter unit.

[0005] Patent document DE69405962T2 also describes an accelerometer having a test block and a piezoelectric system on a printed circuit board. This accelerometer detects acceleration as a shear force along an axis based on the transverse shear effect. The piezoelectric system is arranged between the test block and the printed circuit board. A converter unit is located on the printed circuit board.

[0006] The piezoelectric system in patent document CH399021A1 is sensitive only to normal forces along the axis. The piezoelectric system in patent document DE69405962T2 is sensitive only to shear forces along the axis. However, what is desired is an accelerometer capable of simultaneously detecting accelerations along multiple axes of a Cartesian coordinate system.

[0007] Patent document RU1792537C1 discloses an accelerometer capable of detecting acceleration in three physical dimensions. A piezoelectric system comprising six flat disks made of piezoelectric material and six test blocks is assembled on a cubic substrate with six surfaces. Each pair of surfaces is oriented normally relative to one of three mutually perpendicular axes, hereinafter referred to as the normal axis. On each of the six surfaces, a flat disk is arranged between the surface and the test block. These disks are mechanically pre-tightened to the substrate by an external pre-tightening housing. Thus, the piezoelectric system has a pair of disks for each of the three normal axes. These disks are highly sensitive to transverse shear effects. In the case of a transverse shear effect, piezoelectric point charges are generated on the same end face of the disk on which the shear force acts tangentially to the normal axis, hereinafter referred to as the principal tangential axis. The piezoelectric system also has electrodes made of conductive material for extracting piezoelectric charges from the end faces of the disks.

[0008] According to document RU1792537C1, the piezoelectric system has a pair of disks made of piezoelectric material for each of the three normal axes, which are highly sensitive to shear forces along the principal tangential axis.

[0009] Unfortunately, it is unavoidable that piezoelectric materials exhibit varying degrees of sensitivity to shear forces along different axes. Therefore, a piezoelectric material that is highly sensitive to shear forces along the principal tangential axis may exhibit low sensitivity to shear forces along a axis perpendicular to both the principal tangential axis and the normal axis, referred to below as the secondary tangential axis. These two shear forces, one along the principal tangential axis and the other along the secondary tangential axis, generate piezoelectric charges on the end faces of the disk. For example, quartz, as a piezoelectric material, exhibits a high sensitivity to shear forces along the principal tangential axis, up to seven times higher than its low sensitivity to shear forces along the secondary tangential axis.

[0010] Therefore, the low sensitivity of piezoelectric materials to shear forces along the secondary tangential axis may distort the detection of shear forces along the primary tangential axis; the corresponding piezoelectric charges are referred to below as piezoelectric interference charges. To avoid this distortion, according to document RU1792537C1, a pair of disks with opposite polarities are connected in series for each of the three normal axes. The advantage of this is that the shear force acting along the secondary tangential axis generates the same number of piezoelectric interference charges on the end faces of the two disks, but these piezoelectric interference charges have opposite polarities and are neutralized by the series connection.

[0011] Patent document EP054680A1 also describes an acceleration sensor that utilizes a piezoelectric system to detect acceleration as shear force along three mutually perpendicular principal tangential axes with high sensitivity, based on the transverse shear effect. Figure 8 In this implementation, the piezoelectric system consists of six disks made of piezoelectric material, with a pair of disks of opposite polarities connected in series for each of the three principal tangential axes. The accelerometer requires only three test blocks, one for each of the three principal tangential axes. Through this series-and-drop connection, the piezoelectric interference charges originating from the shear force along the secondary tangential axis are neutralized for each of the three principal tangential axes.

[0012] Patent document US5539270A1 also relates to an accelerometer for detecting acceleration in three physical dimensions. Each dimension is configured with a piezoelectric system, each piezoelectric system having two plates made of piezoelectric material. The two plates are connected to each other via material-fitting end faces facing each other. The material-fitting connection is electrically insulating. Electrodes are assembled on the opposite end faces of the plates, these electrodes capturing piezoelectric charges generated under normal force. The three piezoelectric systems are mechanically fastened to a support. The support has an electrical conductor that conducts the piezoelectric charges from the electrodes. No test block is provided.

[0013] Typically, only a small amount of space is available to mount the accelerometer to the physical object. Therefore, the accelerometer should have a small external size, less than 50 cm³. The desired measurement frequency is above 10 kHz. And since the resonant frequency of the accelerometer is inversely proportional to its weight, the accelerometer should be lightweight.

[0014] Patent document CN201152880Y discloses an accelerometer comprising a piezoelectric system, a test block, and a substrate. The substrate is cylindrical and terminates along a vertical axis at a normal end face. The piezoelectric system is mechanically pre-tightened between the substrate and the test block by a pre-tightening sleeve along a normal axis perpendicular to the vertical axis. The pre-tightening sleeve is hollow cylindrical and terminates laterally in a plane at the normal end face of the substrate. The test block is disc-shaped and also terminates laterally in a plane at the normal end face of the substrate. In an embodiment of a charge amplifier, a converter unit is disposed in this plane, on the sides of the pre-tightening sleeve and the test block, and on the normal end face of the substrate, thereby saving space.

[0015] The disadvantage of arranging the converter unit on the sides of the preload sleeve and the test block, as well as on the normal end face of the substrate, is that a force shunting occurs between the test block and the substrate. The test block can no longer vibrate freely under acceleration, thus suppressing the force exerted on the piezoelectric system due to the inertia of the test block. Consequently, the force is no longer proportional to the acceleration, and the piezoelectric charge generated by the piezoelectric material is also no longer proportional to the acceleration being detected. Therefore, this force shunting distorts the detection of acceleration. Summary of the Invention

[0016] The first objective of this invention is to provide an accelerometer capable of simultaneously detecting acceleration in multiple physical dimensions. The second objective is to provide an accelerometer that detects acceleration with minimal distortion. The third objective is that the accelerometer should have a small external size and light weight. The fourth objective is to provide an accelerometer for high measurement frequencies greater than 10 kHz. The fifth objective is that the accelerometer should be manufactured at low cost.

[0017] At least one of the above objectives is achieved through the features of the technical solution of the present invention.

[0018] This invention relates to an accelerometer having at least one piezoelectric element, at least one test block, and a substrate; the accelerometer is arranged in a Cartesian coordinate system having three axes, one of which is a vertical axis; and the substrate has tangential and normal sides, the tangential sides being arranged tangentially relative to the vertical axis and the normal sides being arranged normally relative to the vertical axis; wherein the accelerometer has exactly three piezoelectric elements and exactly three test blocks; wherein exactly one piezoelectric element is fastened to each of the three tangential sides; wherein exactly one test block is fastened to each of the three piezoelectric elements, and a shear force proportional to the acceleration is applied to the piezoelectric element during acceleration; wherein each of the three piezoelectric elements has high sensitivity to the shear force applied along a principal tangential axis by the test block fastened thereto, and the principal tangential axis of each of the three piezoelectric elements is a different one of the three axes.

[0019] Therefore, the accelerometer according to the invention can simultaneously detect acceleration along three axes. For this purpose, exactly one piezoelectric element is provided for each of the three axes, which has high sensitivity to the shear force to be detected and detects the shear force independently of the other two piezoelectric elements. The accelerometer according to the invention has a very compact structure because it requires only three piezoelectric elements and three test blocks, and these three piezoelectric elements and three test blocks are arranged in a space-saving manner on three tangential sides of the substrate. In contrast, patent document RU1792537C1 teaches the use of six piezoelectric elements and six test blocks on six surfaces of a cubic substrate. According to the invention, the number of required piezoelectric elements and test blocks is also halved, and the space requirement is correspondingly reduced.

[0020] Other preferred embodiments of the present invention are described below. Attached Figure Description

[0021] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments. Wherein:

[0022] Figure 1 A view as part of a first embodiment of an accelerometer with a sensor unit;

[0023] Figure 2 A view as part of a second embodiment of an accelerometer with a sensor unit;

[0024] Figure 3 For having a basis Figure 1 A view of the sensor unit of the converter unit of the accelerometer sensor;

[0025] Figure 4 For having a basis Figure 2 A view of the sensor unit of the converter unit of the accelerometer sensor;

[0026] Figure 5 According to Figures 1 to 4 An exploded view of a portion of the sensor unit;

[0027] Figure 6 According to Figures 1 to 5 A top view of the sensor unit under acceleration.

[0028] Figure 7 According to Figures 1 to 5 A first view of a first embodiment of the piezoelectric element of the sensor unit;

[0029] Figure 8 According to Figure 7 A second view of an embodiment of a piezoelectric element;

[0030] Figure 9 According to Figures 1 to 5 A first view of a second embodiment of the piezoelectric element of the sensor unit;

[0031] Figure 10 According to Figure 9 A second view of a second embodiment of a piezoelectric element;

[0032] Figure 11 For export based on Figures 1 to 5 A schematic diagram of the piezoelectric charge of the sensor unit;

[0033] Figure 12 According to Figure 11 A schematic diagram of the high-pass filter of the converter unit of the sensor unit;

[0034] Figure 13 According to Figure 11 A schematic diagram of the low-pass filter of the converter unit of the sensor unit;

[0035] Figure 14 For assembly according to Figure 2 A view of the first step of the accelerometer, in which a signal conductor is guided into the housing;

[0036] Figure 15 For assembly according to Figure 2 A view of the second step of the accelerometer, wherein the signal conductor in the housing is encapsulated with potting material;

[0037] Figure 16 For assembly according to Figure 2 A view of the third step of the accelerometer, wherein the signal conductor, encapsulated in potting material, is regionally exposed within the housing;

[0038] Figure 17 For assembly according to Figure 2 A view of the fourth step of the accelerometer, wherein the sensor unit is placed into the housing; and

[0039] Figure 18 For assembly according to Figure 2 A view of the fifth step of the accelerometer, in which the converter unit electrically contacts the sensor unit.

[0040] The list of reference numerals in the attached figures is as follows:

[0041] 1. Accelerometer

[0042] 1.1 Sensor Unit

[0043] 1.2 Shell

[0044] 1.20 Casing opening

[0045] 1.21 Housing cover

[0046] 1.22 Signal output opening

[0047] 1.23 Bottom of the casing

[0048] 1.24 Assembly gap

[0049] 1.3 Converter Unit

[0050] 1.4 Signal Output Terminal

[0051] 10, 10′, 10″ piezoelectric element

[0052] 11, 11', 11'' Test Block

[0053] 12 Matrix

[0054] 12.1, 12.2, 12.3, 12.4 Tangential side

[0055] 12.6, 12.7 Normal side

[0056] 13.01, 13.01', 13.01'' First piezoelectric element contact

[0057] 13.02, 13.02', 13.02'' Second piezoelectric element contact

[0058] 13.03, 13.03', 13.03'' First base input contact

[0059] 13.04, 13.04', 13.04'' Second base input contact

[0060] 13.08, 13.08', 13.08'' First base output contact

[0061] 13.09 Second base output contact

[0062] 13.1, 13.1', 13.1'' First piezoelectric element conductor

[0063] 13.2, 13.2', 13.2'' Second piezoelectric element conductor

[0064] 13.3, 13.3', 13.3' First base conductor

[0065] 13.4, 13.4', 13.4'' Second matrix conductor

[0066] 13.5, 13.5', 13.5'' First resistor

[0067] 13.6, 13.6', 13.6'' Second resistor

[0068] 13.7 Bracket

[0069] 13.8, 13.8', 13.8'' First substrate output conductor

[0070] 13.9 Second substrate output conductor

[0071] 13.10, 13.10', 13.10'' transimpedance converter

[0072] 14.1, 14.1', 14.1'' First signal conductor

[0073] 14.2 Second signal conductor

[0074] 14.3 Protective Cover

[0075] 14.4 Sheath Flange

[0076] 14.5 Electrical insulation components

[0077] 14.6 Potting Materials

[0078] 14.7 Exposed areas

[0079] 15, 15', 15'' Internal connection device

[0080] 16, 16', 16'' External connection devices

[0081] 17, 17', 17'' Low-pass filter

[0082] 18, 18', 18'' high-pass filter

[0083] 101 First conductive coating

[0084] 102 Second conductive coating

[0085] 110, 120 end faces

[0086] 111, 111' First conductive end face coating

[0087] 112, 112', 112'' First uncoated end region

[0088] 121 - 121''' Second conductive end face coating

[0089] 122, 122', 122'' Second uncoated end region

[0090] 130, 140, 150, 160 (side views)

[0091] 131, 131' First conductive side coating

[0092] 132, 132' - 132'''' First uncoated side region

[0093] 133, 133' Additional first conductive side coating

[0094] 141 Second conductive side coating

[0095] 142, 142', 142'' Second uncoated side region

[0096] 151, 151' Third conductive side coating

[0097] 161 Fourth conductive side coating

[0098] a Normal axis

[0099] F force

[0100] h Principal tangential axis

[0101] n Secondary tangential axis

[0102] S1, S2 acceleration signals

[0103] x-axis

[0104] y-axis

[0105] z vertical axis Detailed Implementation

[0106] Figure 1 and Figure 2A portion of two embodiments of the accelerometer sensor 1 according to the present invention is shown. The accelerometer sensor 1 has a sensor unit 1.1, a housing 1.2, a converter unit 1.3, and a signal output terminal 1.4. The accelerometer sensor 1 is arranged in a Cartesian coordinate system having three axes x, y, and z, which are also referred to as the horizontal axis x, the vertical axis y, and the vertical axis z.

[0107] The housing 1.2 protects the accelerometer 1 from harmful environmental influences such as contaminants (dust, moisture, etc.) and electromagnetic interference in the form of electromagnetic radiation. The housing 1.2 is made of a mechanically resistant material, such as a pure metal, nickel alloy, cobalt alloy, or iron alloy. The housing 1.2 has a rectangular cross-section, the width along the horizontal axis x is preferably less than 5 cm, the length along the vertical axis y is preferably less than 5 cm, and the height along the vertical axis z is preferably less than 2 cm, thus the housing has a cross-section of less than 50 cm. 3 The external dimensions of the housing 1.2 are specified. The housing 1.2 is canister-shaped, having a housing opening 1.20 and a housing bottom 1.23. The dimensions of the housing opening 1.20 are determined such that the sensor unit 1.1 can be placed within the housing 1.2 through the housing opening 1.20, fixed by the housing bottom 1.23, and in contact with the signal output terminal 1.4. In this invention, the term "contact" refers to both electrical and mechanical connections. The housing opening 1.20 can be closed by a housing cover 1.21. Preferably, this closure is achieved through a material fit, such as welding, brazing, or bonding. The accelerometer 1 is secured to the physical object whose acceleration is to be detected via the housing 1.2. The type and manner of securing are arbitrary.

[0108] The sensor unit 1.1 has first, second, and third piezoelectric elements 10, 10′, and 10″, first, second, and third test blocks 11, 11′, and 11″, and a substrate 12. The first, second, and third piezoelectric elements 10, 10′, and 10″, and the first, second, and third test blocks 11, 11′, and 11″ are fastened to the substrate 12. The substrate 12 is in turn fastened to the housing 1.2. Preferably, the substrate 12 is fastened to the housing 1.2 by means of material fitting (e.g., bonding, brazing, etc.).

[0109] The first, second, and third piezoelectric elements 10, 10′, and 10″ are made of piezoelectric materials, such as quartz (SiO2 single crystal) and calcium gallium germanate (Ca3Ga2Ge4O3). 14 Or CGG), lanthanum gallium silicate (La3Ga5SiO) 14 Materials include LGS (or tourmaline), gallium phosphate, and piezoelectric ceramics. The first, second, and third piezoelectric elements 10, 10′, and 10″ exhibit high sensitivity to the received force. The cross-sections of the first, second, and third piezoelectric elements 10, 10′, and 10″ are rectangular, and their areas are preferably less than 1 cm². 2Furthermore, its thickness is preferably less than 2 mm. With an understanding of the present invention, those skilled in the art can realize piezoelectric elements with different formations and other cross-sectional shapes (e.g., circular).

[0110] Preferably, the first, second, and third test blocks 11, 11′, and 11″ are made of high-density materials, such as iridium, platinum, tungsten, and gold. Due to the small external size of the accelerometer 1, the first, second, and third test blocks 11, 11′, and 11″ preferably have a density greater than 19 g / cm³. 3 High density. The cross-sections of the first, second, and third test blocks 11, 11′, and 11″ are rectangular, and their area is preferably less than 1 cm². 2 Furthermore, its thickness is preferably less than 5 mm. Those skilled in the art, upon understanding this invention, can produce test blocks with different formations and other cross-sectional shapes (e.g., circular). Those skilled in the art can also use test blocks made of low-density materials (e.g., steel, ceramics, etc.).

[0111] The substrate 12 is made of a low-density, mechanically rigid material, such as Al2O3, ceramics, Al2O3 ceramics, sapphire, etc. The substrate 12 is mechanically rigid to transmit the acceleration to be detected inelastically from the housing 1.1 to the first, second, and third test blocks 11, 11′, 11″. For the high mechanical stiffness of the accelerometer 1, the substrate 12 preferably has a high elastic modulus of 350 GPa to 470 GPa. Due to the light weight of the accelerometer 1, the substrate 12 preferably has a modulus of less than 4 g / cm³. 3 The substrate 12 is preferably a cube with six sides 12.1, 12.2, 12.3, 12.4, 12.6, and 12.7. Four tangential sides 12.1, 12.2, 12.3, and 12.4 are arranged tangentially with respect to the vertical axis z. Two normal sides 12.6 and 12.7 are arranged normally with respect to the vertical axis z. Sides 12.1, 12.2, 12.3, 12.4, 12.6, and 12.7 are largely the same size. Each side 12.1, 12.2, 12.3, 12.4, 12.6, and 12.7 has a density of less than 1 cm. 2 The area. In the context of this invention, the adjective "to a large extent" has the meaning of "+ / -10%". Each axis x, y, z is normal to both sides. With knowledge of this invention, those skilled in the art can realize substrates with different formations and other surface shapes (e.g., circular).

[0112] The first test block 11 and the first piezoelectric element 10 are fastened to the first tangential side 12.1 of the substrate 12. The second test block 11' and the second piezoelectric element 10' are fastened to the second tangential side 12.2 of the substrate 12. The third test block 11″ and the third piezoelectric element 10″ are fastened to the third tangential side 12.3 of the substrate 12. Here, a piezoelectric element 10, 10', and 10″ are respectively arranged between the tangential sides 12.1, 12.2, and 12.3 and the test blocks 11, 11', and 11″. The fourth tangential side 12.4 is empty.

[0113] The first, second, and third test blocks 11, 11', 11″ and the first, second, and third piezoelectric elements 10, 10', 10″ are secured to the substrate 12 via the first, second, and third internal connecting devices 15, 15', 15″ and the first, second, and third external connecting devices 16, 16', 16″. This securing is achieved through material bonding, such as adhesive bonding or thermoforming. This mechanical securing of the first, second, and third test blocks 11, 11', 11″ and the first, second, and third piezoelectric elements 10, 10', 10″ via the first, second, and third internal connecting devices 15, 15', 15″ and the first, second, and third external connecting devices 16, 16', 16″ facilitates the assembly of the accelerometer 1 and enables rapid and low-cost execution.

[0114] The first, second, and third internal connecting devices 15, 15', 15″ and the first, second, and third external connecting devices 16, 16', 16″ are chemically curable adhesives or physically curable adhesives, or a combination of chemically curable adhesives and physically curable adhesives. Preferably, the first, second, and third internal connecting devices 15, 15', 15″ and the first, second, and third external connecting devices 16, 16', 16″ are made of adhesives, such as epoxy resin, polyurethane, cyanoacrylate, methyl methacrylate, etc. The first, second, and third internal connecting devices 15, 15', 15″ and the first, second, and third external connecting devices 16, 16', 16″ have a density greater than 10. 12 Ωmm 2 An electrical insulator with a specific resistance of / m.

[0115] like Figure 5As shown, the first piezoelectric element 10 is fastened to the first tangential side 12.1 by the first internal connecting device 15. The first test block 11 is fastened to the first piezoelectric element 10 by the first external connecting device 16. The second piezoelectric element 10′ is fastened to the second tangential side 12.2 by the second internal connecting device 15′. The second test block 11′ is fastened to the second piezoelectric element 10′ by the second external connecting device 16′. The third piezoelectric element 10″ is fastened to the third tangential side 12.3 by the third internal connecting device 15″. The third test block 11″ is fastened to the third piezoelectric element 10″ by the third external connecting device 16″.

[0116] Preferably, the first, second, and third piezoelectric elements 10, 10′, 10″ are fastened to the first, second, and third test blocks 11, 11′, 11″ and the substrate 12 in a shear-resistant manner via the first, second, and third internal connecting devices 15, 15′, 15″ and the first, second, and third external connecting devices 16, 16′, 16″.

[0117] The cross-section of each of the first, second, and third internal connecting devices 15, 15′, 15″ and each of the first, second, and third external connecting devices 16, 16′, 16″ is rectangular, preferably with a cross-section of less than 1 cm. 2 The area and preferably a thickness of less than 0.1 mm. Those skilled in the art, upon understanding this invention, can implement internal and external connecting devices with different formations and other cross-sectional shapes (e.g., circles).

[0118] The first, second, and third piezoelectric elements 10, 10′, and 10″ exhibit high sensitivity to transverse shear effects along the principal tangential axis h, low sensitivity to transverse shear effects along the secondary tangential axis n, and low sensitivity to piezoelectric transverse effects along the normal axis a. For each of the three piezoelectric elements 10, 10′, and 10″, the principal tangential axis h is a different one of the three axes x, y, and z. For each of the three piezoelectric elements 10, 10′, and 10″, the secondary tangential axis n is a different one of the three axes x, y, and z. For each of the three piezoelectric elements 10, 10′, and 10″, the normal axis a is a different one of the three axes x, y, and z.

[0119] Under the lateral shear effect along the primary tangential axis h or the secondary tangential axis n, piezoelectric charges are generated on the same end faces of the first, second, and third piezoelectric elements 10, 10′, and 10″, and shear forces act on these end faces along the primary tangential axis h or the secondary tangential axis n.

[0120] Under the piezoelectric transverse effect, piezoelectric charges are generated on the side surfaces of the first, second, and third piezoelectric elements 10, 10′, and 10″, and a normal force acts on the end face of the first, second, and third piezoelectric elements 10, 10′, and 10″ along the normal axis a.

[0121] Given a specific force, higher sensitivity results in more piezoelectric charge. In the context of this invention, the terms "high sensitivity" and "low sensitivity" are related. Each of the three piezoelectric elements 10, 10′, and 10″ produces at least five times more piezoelectric charge per unit force with high sensitivity to a shear force along the principal tangential axis h than with low sensitivity to a shear force along the secondary tangential axis n or a normal force along the normal axis a.

[0122] Therefore, the piezoelectric material was chosen to detect acceleration primarily by considering the piezoelectric charge from the transverse shear effect along the principal tangential axis h. In the following text, the piezoelectric charge resulting from the transverse shear effect along the secondary tangential plane and the piezoelectric transverse effect along the normal axis a will be referred to as the piezoelectric interference charge.

[0123] Figure 6 This is a top view of sensor unit 1.1 under acceleration. Based on the acceleration, a force F is applied to the end faces of the first, second, and third piezoelectric elements 10, 10', and 10'' through the first, second, and third test blocks 11, 11', and 11'″. This force F acts, for example, parallel to the longitudinal axis y, as indicated by the arrow.

[0124] The first piezoelectric element 10 exhibits high sensitivity to shear forces along the longitudinal axis y, which is the principal tangential axis h. Since the force F acts along the longitudinal axis y, the first piezoelectric element 10 generates piezoelectric charges on its end face in response to this force based on the transverse shear effect. The first piezoelectric element 10 exhibits low sensitivity to shear forces along the vertical axis z, which is the secondary tangential axis n, and low sensitivity to normal forces along the transverse axis x, which is the normal axis a. The force F acts along the longitudinal axis y and applies torque along the vertical axis z. The first piezoelectric element 10 generates piezoelectric interference charges on its end face in response to this torque based on the transverse shear effect.

[0125] The second piezoelectric element 10' exhibits high sensitivity to shear forces along the transverse axis x, which is the principal tangential axis h. However, since the force F acts along the longitudinal axis y, the second piezoelectric element 10' does not generate piezoelectric charges on its end face. The second piezoelectric element 10' exhibits low sensitivity to shear forces along the vertical axis z, which is the secondary tangential axis n, and low sensitivity to normal forces along the longitudinal axis y, which is the normal axis a. Since the force F acts along the longitudinal axis y, the second piezoelectric element 10' generates piezoelectric interference charges on its side surface according to the piezoelectric transverse effect.

[0126] The third piezoelectric element 10″ is highly sensitive to shear forces along the vertical axis z, which is the principal tangential axis h. However, since force F acts as a shear force along the longitudinal axis y, the third piezoelectric element 10″ does not generate piezoelectric charges on its end face. The third piezoelectric element 10″ is less sensitive to shear forces along the longitudinal axis y, which is the secondary tangential axis n, and less sensitive to normal forces along the transverse axis x, which is the normal axis a. Force F acts along the longitudinal axis y and applies torque along the vertical axis z. The third piezoelectric element 10″ generates piezoelectric interference charges on its end face in response to this torque, based on the transverse shear effect.

[0127] Figure 7 and Figure 8 A first embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ of the sensor unit 1.1 is shown in detail. Figure 9 and Figure 10 A second embodiment of the first, second, or third piezoelectric element 10, 10′, 10″ of the sensor unit 1.1 is shown in detail. The first, second, or third piezoelectric element 10, 10′, 10″ has two end faces 110, 120 and four side faces 130, 140, 150, 160.

[0128] Each of the three piezoelectric elements 10, 10′, and 10″ has a first end face 110 and a second end face 120. Each end face 110 and 120 lies in a plane formed by the principal tangential axis h and the secondary tangential axis n. In this plane, the secondary tangential axis n is perpendicular to the principal tangential axis h. The normal axis a is located in the normal direction of this plane. Under the action of a shear force along the principal tangential axis h, each of the three piezoelectric elements 10, 10′, and 10″ generates piezoelectric charges on the two end faces 110 and 120. Furthermore, under the action of a shear force along the secondary tangential axis, each of the three piezoelectric elements 10, 10′, and 10″ generates piezoelectric interference charges on the two end faces 110 and 120. Each of the three piezoelectric elements 10, 10′, and 10″ has side faces 130, 140, 150, and 160. These side faces 130, 140, 150, and 160 are parallel to the normal axis a. These sides 130, 140, 150, and 160 include a first side 130, a second side 140, a third side 150, and a fourth side 160. The first side 130 and the fourth side 160 are normal to the secondary tangential axis n of the piezoelectric elements 10, 10′, and 10″. The second side 140 and the third side 150 are normal to the principal tangential axis h of the piezoelectric elements 10, 10′, and 10″.

[0129] Under the action of the normal force along the normal axis, each of the three piezoelectric elements 10, 10′, and 10″ generates piezoelectric interference charges on the four sides 130, 140, 150, and 160.

[0130] Therefore, the piezoelectric charge used to detect the shear force is generated only on the two end faces 110 and 120 of the piezoelectric element. However, the piezoelectric interference charge is generated not only on the two end faces 110 and 120, but also on the four sides 130, 140, 150, and 160.

[0131] End faces 110 and 120 locally have at least one conductive end face coating 111 and 121. The size of the area of ​​the conductive end face coating 111 and 121 can be between 90% and 100% of the end faces 110 and 120. Side faces 130, 140, 150, and 160 locally have at least one conductive side face coating 131, 141, 151, and 161. The size of the area of ​​the conductive side face coating 131, 141, 151, and 161 can be between 0% and 100% of the side faces 130, 140, 150, and 160. The conductive end face coating 111 and 121 and the conductive side face coating 131, 141, 151, and 161 can be formed by thermal coating of metal foil or by metal deposition. The metal can be copper, copper alloy, gold, gold alloy, aluminum, aluminum alloy, silver, silver alloy, etc. The thickness of the conductive end face coatings 111, 121 and the conductive side face coatings 131, 141, 151 and 161 is preferably less than 0.1 mm.

[0132] Therefore, the accelerometer 1 no longer has physical electrodes, but only conductive end-face coatings 111, 121 and conductive side-face coatings 131, 141, 151, 161. This results in fewer components, saving space and simplifying the assembly of the accelerometer 1.

[0133] Because of the conductive end-face coatings 111, 121 and the conductive side-face coatings 131, 141, 151, 161, mechanical pre-tightening of the first, second, or third piezoelectric elements 10, 10′, 10″ is not necessary. This is because the conductive end-face coatings 111, 121 and the conductive side-face coatings 131, 141, 151, 161 are material-fitted onto the end faces 110, 120 and the sides 130, 140, 150, 160, and seal off the tiny holes in the end faces 110, 120 and the sides 130, 140, 150, 160. By sealing these tiny holes, the accelerometer 1 no longer requires any separate pre-tightening device, such as the pre-tightening sleeve described in patent document CH399021A1 or the pre-tightening housing described in patent document RU1792537C1. Therefore, fewer parts are required, saving space and weight and simplifying the assembly of the accelerometer 1.

[0134] according to Figure 7 and Figure 8 In a first embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first end face 110 partially has two first conductive end face coatings 111, 111′, and partially has two first uncoated end face regions 112, 112′. The second end face 120 partially has more than two conductive end face coatings 121, 121′, 121″. The first side face 130 partially has a first conductive side face coating 131, partially has another first conductive side face coating 133, and partially has multiple uncoated first side face regions 132, 132′, 132″, 132″′, 132″″. The second side face 140 partially has a second conductive side face coating 141 and partially has a second uncoated side face region 142. The third side face 150 partially has a third conductive side face coating 151 and partially has two uncoated third side face regions 152, 152′. The fourth side 160 has a fourth conductive side coating 161 in a partial manner.

[0135] according to Figure 7 and Figure 8 In a first embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the two first conductive end-face coatings 111, the additional first conductive side-face coating 133, and the third conductive side-face coating 151 form a first continuous conductive coating 101. A plurality of second conductive end-face coatings 121, 121′, 121″, the first conductive side-face coating 131, the second conductive side-face coating 141, and the fourth conductive side-face coating 161 form a second continuous conductive coating 102.

[0136] In the context of this invention, the term "continuous" signifies "interconnected in a conductive manner." The first continuous conductive coating 101 captures the first piezoelectric charge generated on the surface of the first, second, or third piezoelectric elements 10, 10′, 10″ below the first continuous conductive coating 101 as the first acceleration signal S1. The second continuous conductive coating 102 captures the second piezoelectric charge generated on the surface of the first, second, or third piezoelectric elements 10, 10′, 10″ below the second continuous conductive coating 102 as the second acceleration signal S2. The first and second piezoelectric charges have different signs. Either the first piezoelectric charge has a negative sign and the second piezoelectric charge has a positive sign, or the first piezoelectric charge has a positive sign and the second piezoelectric charge has a negative sign.

[0137] Preferably, the first conductive end face coating 111 and the first conductive side face coating 131 form a first continuous conductive coating 101. Preferably, the second conductive end face coating 121 and another first conductive side face coating 133 form a second continuous conductive coating 102. Preferably, at least one second, third, or fourth conductive side face coating 141, 151, 161 is a part of the first continuous conductive coating 101 or a part of the second continuous conductive coating 102.

[0138] according to Figure 7 and Figure 8 In the first embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first continuous conductive coating 101 and the second continuous conductive coating 102 are electrically insulated from each other through two first uncoated end face regions 112, 112′, multiple first uncoated side face regions 132, 132′, 132″, 132″′, 132″″, second uncoated side face region 142, and two third uncoated side face regions 152, 152′.

[0139] according to Figure 9 and Figure 10In a second embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first end face 110 partially has a first conductive end face coating 111 and partially has a plurality of first uncoated end face regions 112, 112′, 112″. The second end face 120 partially has a plurality of second conductive end face coatings 121, 121′, 121″ and partially has a second uncoated end face region 122. The first side face 130 partially has a first conductive side face coating 131, partially has two additional first conductive side face coatings 133, 133′, and partially has a plurality of first uncoated side face regions 132, 132′, 132″. The second side 140 partially has a second conductive side coating 141, and partially has a plurality of second uncoated side regions 142, 142', 142''. The third side 150 partially has a third conductive side coating 151, and partially has third uncoated side regions 152, 152''. The fourth side 160 partially has a fourth conductive side coating 161.

[0140] according to Figure 9 and Figure 10 In a second embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the plurality of first conductive end-face coatings 112, 112′, 112″ and the two first conductive side-face coatings 131, 131′ form a first continuous conductive coating 101. The plurality of second conductive end-face coatings 121, 121′, 121″, the two additional first conductive side-face coatings 133, 133′, the second conductive side-face coating 141, the third conductive side-face coating 151, and the fourth conductive side-face coating 161 form a second continuous conductive coating 102.

[0141] according to Figure 9 and Figure 10 In the second embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the conductive side coatings 131, 131′ of the first continuous conductive coating 101 intercept piezoelectric interference charges under normal force along the normal axis a. The polarity of these piezoelectric interference charges is opposite to the polarity of the piezoelectric interference charges intercepted by the first conductive end coating 111 of the first continuous conductive coating 101 under shear force along the secondary tangential axis n. Furthermore, the conductive side coatings 133, 141, 151, 161 of the second continuous conductive coating 102 intercept piezoelectric interference charges under normal force along the normal axis a. The polarity of these piezoelectric interference charges is opposite to the polarity of the piezoelectric interference charges intercepted by the second conductive end coatings 121, 121′, 121″ of the second continuous conductive coating 102 under shear force along the secondary tangential axis n.

[0142] according to Figure 9 and Figure 10In the second embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first conductive coating 101 and the second conductive coating 102 are electrically insulated from each other through a plurality of first uncoated end face regions 112, 112′, 112″, second uncoated end face region 122, a plurality of first uncoated side face regions 132, 132′, 132″, a plurality of second uncoated side face regions 142, 142′, 142″ and third uncoated side face region 152.

[0143] The ratio of the size of the first conductive coating 131 to the size of the other first conductive coating 133 can be adjusted by the relative position and / or size of the first uncoated side regions 132, 132′, 132″, 132″′, 132″″ of the first side 130. In the context of this invention, the conjunction “and / or” means that either only one of the conjunctions occurs, or both conjunctions occur.

[0144] The ratio of the size of the first conductive coating 131 to the size of the other first conductive coating 133 can be adjusted by the relative positions of the first uncoated side regions 132, 132', 132″, 132″', 132″″ about the second and third sides 140, 150. Based on the relative positions of the first uncoated side regions 132, 132', 132″, 132″', 132″″ about the second side 140 or about the third side 150, the ratio of the size of the first conductive coating 131 to the size of the other first conductive coating 133 can be correspondingly decreased or increased. Figure 7 and Figure 8 In the first embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first uncoated side regions 132, 132′, 132″, 132″′, 132″″ are relatively close to the second side 140. According to Figure 9 and Figure 10 In the second embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first uncoated side regions 132, 132′, 132″ are relatively equidistant from the second and third sides 140, 150.

[0145] However, the ratio of the size of the first conductive coating 131 to the size of the other first conductive coating 133 can also be adjusted by increasing or decreasing the size of the first uncoated side regions 132, 132', 132″, 132″′, 132″″ of the first side 130. Figure 7 and Figure 8In the first embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first uncoated side regions 132, 132′, 132″, 132″′, 132″″ are substantially twice the size of the additional first conductive coating 133, and the first uncoated side regions 132, 132′, 132″, 132″′, 132″″ are substantially five times smaller than the first conductive coating 131. Figure 9 and Figure 10 In the second embodiment of the first, second, or third piezoelectric elements 10, 10′, 10″ shown, the first uncoated side regions 132, 132′, 132″ are substantially the same size as the first conductive coatings 131, 131′ and the additional first conductive coating 133.

[0146] Preferably, the conductive side coating of the first conductive coating 101 intercepts piezoelectric interference charges under normal force along the normal axis a, and the polarity of these piezoelectric interference charges is opposite to the polarity of the piezoelectric interference charges intercepted by the first conductive end coating of the first conductive coating 101 under shear force along the secondary tangential axis n. Similarly, the conductive side coating of the second conductive coating 102 intercepts piezoelectric interference charges under normal force along the normal axis, and the polarity of these piezoelectric interference charges is opposite to the polarity of the piezoelectric interference charges intercepted by the second conductive end coating of the second conductive coating 102 under shear force along the secondary tangential axis n.

[0147] Preferably, the size of the conductive side coating of the first continuous conductive coating 101 is adjusted such that the piezoelectric interference charge intercepted by the conductive side coating in response to the normal force along the normal axis a is substantially the same as the piezoelectric interference charge intercepted by the first conductive end coating of the first continuous conductive coating 101 in response to the shear force along the secondary tangential axis n. Furthermore, the piezoelectric interference charge intercepted by the conductive side coating of the second continuous conductive coating 102 in response to the normal force along the normal axis a is substantially the same as the piezoelectric interference charge intercepted by the second conductive end coating of the second interconnecting conductive coating 102 in response to the shear force along the secondary tangential axis n.

[0148] Unlike patent document RU1792537C1, according to the present invention, only one piezoelectric element 10, 10′, 10″ detects shear force per axis. Therefore, the option of connecting two piezoelectric elements in series on each axis to neutralize the piezoelectric interference charges of the shear force along the secondary tangential axis n, which would cause distortion in the detection of shear force along the primary tangential axis h, is no longer possible. Therefore, the accelerometer 1 of the present invention implements an alternative technical solution. Because the piezoelectric material also generates piezoelectric interference charges on the sides 130, 140, 150, 160 for the normal force along the normal axis a, these piezoelectric interference charges also distort the detection of shear force along the primary tangential axis h. Therefore, These piezoelectric interference charges are typically not intercepted by the sides 130, 140, 150, and 160. It is now recognized that the presence of shear force along the secondary tangential axis n is accompanied by a normal force along the normal axis a. The former generates piezoelectric interference charges on the end faces 110 and 120, while the latter generates piezoelectric interference charges on the sides 130, 140, 150, and 160. Both types of piezoelectric interference charges distort the detection of shear force along the principal tangential axis h. However, by means of suitable first and second continuous conductive coatings 101 and 102, the end faces 110 and 120 and the sides 130, 140, 150, and 160 can be electrically connected in series, neutralizing the piezoelectric interference charges that cause the distortion in the detection of shear force along the principal tangential axis h.

[0149] Figure 11 This is a schematic diagram of the piezoelectric charge deriving from sensor unit 1.1. Parts of the first, second, or third piezoelectric elements 10, 10′, 10″ with the first side 130 can be seen, as well as a part of converter unit 1.3 and a part of signal output terminal 1.4.

[0150] The converter unit 1.3 can convert the first acceleration signal S1. The converter unit 1.3 has at least one first and second piezoelectric element conductors 13.1, 13.1′, 13.1″, 13.2, 13.2′, 13.2″, at least one first and second substrate conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″, at least one transimpedance transducer 13.10, 13.10′, 13.10″, and at least one first and second signal output conductors 13.8, 13.8′, 13.8″, 13.9. The converter unit 1.3 also has at least one first resistor 13.5, 13.5′, 13.5″ and / or at least one second resistor 13.6, 13.6′, 13.6″.

[0151] According to Figure 1 and Figure 3In a first embodiment of the accelerometer sensor 1, the converter unit 1.3 is disposed solely and directly on the substrate 12. Preferably, the converter unit 1.3 is disposed solely and directly on the first normal side 12.7 of the substrate 12. According to... Figure 2 and Figure 4 In a second embodiment of the accelerometer sensor 1, the converter unit 1.3 is simply arranged on the bracket 13.7. The bracket 13.7 is made of an electrically insulating material, such as Al2O3, ceramic, Al2O3 ceramic, fiber-reinforced plastic, etc. The bracket 13.7 is fastened to the substrate 12. Preferably, the bracket 13.7 is fastened to the first normal side 12.7 of the substrate 12 by means of material bonding such as adhesive or brazing.

[0152] The first and second piezoelectric element conductors 13.1, 13.1′, 13.1″, 13.2, 13.2′, 13.2″, the first and second base conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″, the first resistors 13.5, 13.5′, 13.5″, the second resistors 13.6, 13.6′, 13.6″, and the transimpedance transducers 13.10, 13.10′, 13.10″ are fastened to the first normal side 12.7 (according to...). Figure 1 and Figure 3 (The first embodiment of the accelerometer 1), or it is fastened to the bracket 13.7 (according to...) Figure 2 and Figure 4 (Second implementation of acceleration sensor 1).

[0153] The first and second piezoelectric element conductors 13.1, 13.1′, 13.1″, 13.2, 13.2′, 13.2″, the first and second substrate conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″, and the first and second signal output conductors 13.8, 13.8′, 13.8″, 13.9 are made of conductive materials such as copper, copper alloys, gold, gold alloys, aluminum, aluminum alloys, etc., and have a diameter of 0.02 mm to 0.10 mm and are mechanically flexible.

[0154] The first and second piezoelectric element conductors 13.1, 13.1′, 13.1″, 13.2, 13.2′, 13.2″, the first and second substrate conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″, and the first and second signal output conductors 13.8, 13.8′, 13.8″, 13.9 conduct the first and second acceleration signals S1 and S2 in a manner insulated from ground. In the context of this invention, the term "insulated from ground" means electrically insulated from the ground of the accelerometer sensor 1. Preferably, the housing 1.2 of the accelerometer sensor 1 is grounded, and the housing 1.2 has the same potential as the local ground. Therefore, the acceleration signals S1 and S2 are conducted electrically insulated from the potential of the accelerometer sensor 1. Thus, the detection of acceleration is not distorted by fluctuations in the potential of the accelerometer sensor 1, such as fluctuations between the housing 1.2 and the converter unit 1.3.

[0155] Preferably, the first and second substrate conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, and 13.4″ are structured within the conductive coating. The conductive coating is achieved through chemical vapor deposition, physical vapor deposition, or the like. The conductive coating is composed of conductive materials, such as copper, copper alloys, gold alloys, platinum, platinum alloys, etc. The conductive coating is a thin conductive layer. In the context of this invention, the term "thin layer" means that the conductive coating has a thickness preferably less than 0.1 mm in the direction perpendicular to the plane. The conductive coating is applied directly to the first normal side 12.7 (according to...). Figure 1 and Figure 3 (According to the first embodiment of the accelerometer 1) or on the bracket 13.7 (according to Figure 2 and Figure 4 (Second embodiment of the accelerometer sensor 1). In the context of this invention, the adjective "directly" means "closely against (unmittelbar)". Preferably, the structuring of the first and second substrate conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″ in the conductive coating is achieved by using a template, photolithography, and laser ablation.

[0156] Preferably, the converter unit 1.3 has three first piezoelectric element conductors 13.1, 13.1′, 13.1″ and three second piezoelectric element conductors 13.2, 13.2′, 13.2″. Each of the first piezoelectric element conductors 13.1, 13.1′, 13.1″ conducts a first acceleration signal S1 from the first conductive coating 101 of the first, second, or third piezoelectric element 10, 10′, 10″ to the converter unit 1.3. Each of the second piezoelectric element conductors 13.2, 13.2′, 13.2″ conducts a second acceleration signal S2 from the second conductive coating 102 of the first, second, or third piezoelectric element 10, 10′, 10″ to the converter unit 1.3.

[0157] First and second piezoelectric element conductors 13.1, 13.1′, 13.1″, 13.2, 13.2′, 13.2″ contact the first side surface 130. Since the first side surface 130 is available and performs a specific technical function—namely, assembling piezoelectric element contacts 13.01, 13.01′, 13.01″ thereon to dissipate piezoelectric charge—space is saved. Each of the first piezoelectric element conductors 13.1, 13.1′, 13.1″ contacts the first conductive side surface coating 131 via the first piezoelectric element contacts 13.01, 13.01′, 13.01″. Each of the second piezoelectric element conductors 13.2, 13.2′, 13.2″ contacts the second piezoelectric element contacts 13.02, 13.02′, 13.01″. 02″ contacts the second conductive side coating 133. The first and second piezoelectric element contacts 13.01, 13.01′, 13.01″, 13.02, 13.02′, and 13.02″ are fastened to the first side 130. The first and second piezoelectric element contacts 13.01, 13.01′, 13.01″, 13.02, 13.02′, and 13.02″ are made of materials such as wire bonding or brazing. For wire bonding, methods such as thermocompression bonding, thermo-ultrasonic ball-wedge bonding, and ultrasonic wedge-wedge bonding are applicable. Figure 11 The first and second circular piezoelectric element contacts 13.01, 13.01′, 13.01″, 13.02, 13.02′, and 13.02″ are molded leads.

[0158] Preferably, the converter unit 1.3 has three first base conductors 13.3, 13.3′, 13.3″ and three second base conductors 13.4, 13.4′, 13.4″. Each of the first piezoelectric element conductors 13.1, 13.1′, 13.1″ contacts the first base conductors 13.3, 13.3′, 13.3″ via first base input contacts 13.03, 13.03′, 13.03″. Each of the second piezoelectric element conductors 13.2, 13.2′, 13.2″ contacts the second base conductors 13.4, 13.4′, 13.4″ via second base input contacts 13.04, 13.04′, 13.04″. The first and second base input contacts 13.03, 13.03′, 13.03″, 13.04, 13.04′, and 13.04″ are fastened to the first normal side 12.7 (according to...). Figure 1 and Figure 3 (The first embodiment of the accelerometer 1), or fastened to the bracket 13.7 (according to...) Figure 2 and Figure 4 (Second embodiment of the accelerometer sensor 1). The first and second substrate input contacts 13.03, 13.03′, 13.03″, 13.04, 13.04′, 13.04″ are made of materials such as wire bonding, brazing, etc. For wire bonding, methods such as thermo-press bonding, thermo-ultrasonic ball-wedge bonding, and ultrasonic wedge-wedge bonding are applicable. Figure 11 The first and second circular base input contacts 13.03, 13.03′, 13.03″, 13.04, 13.04′, and 13.04″ are molded leads.

[0159] The first resistors 13.5, 13.5′, 13.5″, the second resistors 13.6, 13.6′, 13.6″, and the transimpedance transducers 13.10, 13.10′, 13.10″ are electrically connected to each other via the first base conductors 13.3, 13.3′, 13.3″. The second base conductors 13.4, 13.4′, 13.4″ carrying the second acceleration signal S2 with the first, second, and third piezoelectric elements 10, 10′, 10″ are electrically short-circuited and are at the reference potential of the transducer unit 1.3. This reference potential is stable, i.e., a constant DC voltage over time.

[0160] Preferably, the converter unit 1.3 has three transimpedance converters 13.10, 13.10′, and 13.10″. These three transimpedance converters 13.10, 13.10′, and 13.10″ are identically constructed. Figure 1 and Figure 2In the illustrated embodiment, transimpedance transducers 13.10, 13.10′, and 13.10″ are electronic components. The transimpedance transducers 13.10, 13.10′, and 13.10″ are fastened to the first normal side 12.7 via an intermediate medium material (according to...). Figure 1 and Figure 3 (The first embodiment of the accelerometer 1), or fastened to the bracket 13.7 (according to...) Figure 2 and Figure 4 (Second embodiment of the accelerometer 1); and / or transimpedance transducers 13.10, 13.10′, 13.10″ are fastened to the first and second substrate conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″ via an intermediate medium material. The intermediate medium is a chemically cured adhesive, a physically cured adhesive, solder, etc. Preferably, the intermediate medium is an adhesive, such as an epoxide, polyurethane, cyanoacrylate, methyl methacrylate, etc. Each first base conductor 13.3, 13.3′, 13.3″ contacts the transimpedance transducers 13.10, 13.10′, 13.10″. The type and manner of contact are arbitrary. Each first base conductor 13.3, 13.3′, 13.3″ transmits the first acceleration signal S1 to the input terminal of the transimpedance transducers 13.10, 13.10′, 13.10″. Preferably, the input terminals of the transimpedance transducers 13.10, 13.10′, 13.10″ have a value greater than 10. 7 The high impedance is Ω. Transimpedance converters 13.10, 13.10′, and 13.10″ convert the first acceleration signal S1 into a voltage. The converted first acceleration signal S1 is applied to the output terminals of transimpedance converters 13.10, 13.10′, and 13.10″. Preferably, the output terminals of transimpedance converters 13.10, 13.10′, and 13.10″ have a impedance of less than 10Ω. 2 The low impedance is Ω. Those skilled in the art, upon understanding this invention, can also use a charge amplifier instead of the transimpedance converter, having a low resistance at the input of the charge amplifier.

[0161] Figure 12 A schematic diagram of the high-pass filters 18, 18′, and 18″ of the converter unit 1.3 is shown. Preferably, the converter unit 1.3 has three first resistors 13.5, 13.5′, and 13.5″. The three first resistors 13.5, 13.5′, and 13.5″ are constructed identically.

[0162] exist Figure 1 and Figure 2In the illustrated embodiment, the first resistors 13.5, 13.5′, and 13.5″ are resistive coatings made of resistive materials such as Al2O3, ceramics, or Al2O3 ceramics. The resistive coating is achieved through chemical vapor deposition, physical vapor deposition, or the like. The resistive coating is a thin resistive layer. In the context of this invention, the resistive coating is also a "thin layer," preferably having a thickness of less than 0.1 mm in the direction perpendicular to the plane. The resistive coating is applied directly to the first normal side 12.7 (according to...). Figure 1 and Figure 3 (the first embodiment of the accelerometer 1), or on the bracket 13.7 (according to...) Figure 2 and Figure 4 In a second embodiment of the accelerometer 1, and / or a resistive coating is directly applied to the first and second substrate conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″. The resistive coating can be structured using a template, photolithography, laser ablation, etc.

[0163] According to Figure 2 and Figure 4 In one embodiment, the first resistors 13.5, 13.5′, and 13.5″ are electrical components having resistive materials made of ceramics, metal oxides, or the like and connecting wires.

[0164] Each of the first substrate conductors 13.3, 13.3′, 13.3″ contacts a first resistor 13.5, 13.5′, 13.5″. The type and manner of contact are arbitrary. Each of the first resistors 13.5, 13.5′, 13.5″ is electrically connected in parallel with one of the three piezoelectric elements 10, 10′, 10″. This parallel connection forms a high-pass filter 18, 18′, 18″, since the first, second, or third piezoelectric element 10, 10′, 10″ is a capacitor. The high-pass filter 18, 18′, 18″ filters out frequencies below the cutoff frequency. Preferably, the cutoff frequency is 10Hz. When acceleration is first detected using the accelerometer 1, the discharge of the first, second, or third piezoelectric element 10, 10′, 10″ may cause low-interference frequencies below the cutoff frequency. This low-interference frequency is applied to the inputs of transimpedance converters 13.10, 13.10′, and 13.10″, resulting in an undefined time constant. This low-interference frequency may distort the detection of acceleration. By filtering the low-interference frequency, transimpedance converters 13.10, 13.10′, and 13.10″ obtain a defined time constant. The cutoff frequency can be adjusted by the values ​​of the first resistors 13.5, 13.5′, and 13.5″.

[0165] Figure 13A schematic diagram of the low-pass filters 17, 17′, 17″ of the converter unit 1.3 is shown. Preferably, the converter unit 1.3 has three second resistors 13.6, 13.6′, 13.6″. The three second resistors 13.6, 13.6′, 13.6″ are constructed identically. The second resistors 13.6, 13.6′, 13.6″ are electrical components having resistive materials and connecting wires made of, for example, ceramic, metal oxide, etc. The first substrate conductors 13.3, 13.3′, 13.3″ contact the second resistors 13.6, 13.6′, 13.6″. The type and manner of contact are arbitrary. Each second resistor 13.6, 13.6′, 13.6″ is electrically connected in series with one of the three piezoelectric elements 10, 10′, 10″. This series connection forms the low-pass filters 17, 17′, 17″, because the first, second, or third piezoelectric element 10, 10′, 10″ is a capacitor. Low-pass filters 17, 17', and 17″ filter out high interference frequencies higher than the natural frequency of the accelerometer 1. These high interference frequencies are caused by the mechanical excitation of the accelerometer 1. These high interference frequencies are applied to the inputs of the transimpedance converters 13.10, 13.10', and 13.10″, causing them to saturate and resulting in distorted acceleration detection. The low-pass filters 17, 17', and 17″ are adjusted to the natural frequency of the accelerometer 1 based on the values ​​of the second resistors 13.6, 13.6', and 13.6″.

[0166] Preferably, the converter unit 1.3 has three first base output conductors 13.8, 13.8′, and 13.8″. The output terminals of the transimpedance converters 13.10, 13.10′, and 13.10″ contact the first base output contacts 13.08, 13.08′, and 13.08″ via the first base conductors 13.3, 13.3′, and 13.3″. Preferably, the converter unit 1.3 has a second base output conductor 13.9. The second base conductors 13.4, 13.4′, and 13.4″ contact the second base output contact 13.9 via the second base output contact 13.09. The first and second base output contacts 13.08, 13.08′, 13.08″, and 13.09 are fastened to the first normal side 12.7 (according to...). Figure 1 and Figure 3 (The first embodiment of the accelerometer 1), or it is fastened to the bracket 13.7 (according to...) Figure 2 and Figure 4 (Second embodiment of the accelerometer 1). The first and second substrate output contacts 13.08, 13.08′, 13.08″, and 13.09 are made of materials such as wire bonding or brazing. For wire bonding, methods such as thermo-press bonding, thermo-ultrasonic ball-wedge bonding, and ultrasonic wedge-wedge bonding are applicable. Figure 11 The first and second circular base output contacts 13.08, 13.08′, 13.08″, and 13.09 are molded leads.

[0167] The first substrate output conductors 13.8, 13.8′, and 13.8″ transmit the converted first acceleration signal S1 to the signal output terminal 1.4. The second substrate output conductor 13.9 transmits the sum of the second acceleration signal S2 to the signal output terminal 1.4.

[0168] The signal output terminal 1.4 is partially secured to the housing 1.2. Preferably, according to... Figure 1 and Figure 2 In an embodiment of the accelerometer 1, the signal output terminal 1.4 is a cable. The signal output terminal 1.4 has signal conductors 14.1, 14.1′, 14.1″, and 14.2, a protective cover 14.3, a protective cover flange 14.4, an electrical insulation portion 14.5, and a potting material 14.6.

[0169] In cross-section, the signal output terminal 1.4 has a multi-layered structure.

[0170] Signal conductors 14.1, 14.1′, 14.1″, and 14.2 form an inner layer. Preferably, the signal output terminal 1.4 has three first signal conductors 14.1, 14.1′, and 14.1″, and one second signal conductor 14.2. The signal conductors 14.1, 14.1′, 14.1″, and 14.2 are made of conductive materials such as copper, copper alloys, gold, gold alloys, aluminum, and aluminum alloys. Preferably, each signal conductor 14.1, 14.1′, 14.1″, and 14.2 has an electrically insulating sheath. First and second substrate output conductors 13.8, 13.8′, 13.8″, and 13.9 contact the first and second signal conductors 14.1, 14.1′, 14.1″, and 14.2. Each first substrate output conductor 13.8, 13.8′, and 13.8″ contacts a first signal conductor 14.1, 14.1′, and 14.1″. The second substrate output conductor 13.9 contacts the second signal conductor 14.2.

[0171] An electrical insulating portion 14.5 forms an intermediate layer and is arranged around signal conductors 14.1, 14.1′, 14.1″, and 14.2. The electrical insulating portion 14.5 electrically insulates the signal conductors 14.1, 14.1′, 14.1″, and 14.2 relative to the protective cover 14.3. The electrical insulating portion 14.5 is made of an electrical insulating material such as Al2O3, ceramic, Al2O3 ceramic, or fiber-reinforced plastic.

[0172] A protective cover 14.3 forms the outer layer. The protective cover 14.3 protects the electrical insulation portion 14.5 and the signal conductors 14.1, 14.1′, 14.1″, and 14.2 from harmful environmental influences such as contaminants (dust, moisture, etc.) and electromagnetic waves, which may cause undesirable interference effects in the first and second acceleration signals S1 and S2. The protective cover 14.3 is made of a mechanically resistant material, such as metal or plastic.

[0173] Figures 14 to 18 It shows that according to Figure 2 Assembly steps of the acceleration sensor 1 in the embodiment shown.

[0174] Figure 14 The first assembly step is illustrated, in which signal conductors 14.1, 14.1′, 14.1″, and 14.2 are introduced into housing 1.2. Housing 1.2 has a signal output opening 1.22. The signal output opening 1.22 preferably has the shape and size of the outer diameter of a protective cover 14.3. The ends of signal conductors 14.1, 14.1′, 14.1″, and 14.2 are stripped, and the electrical insulation cover has been partially removed. The ends of signal conductors 14.1, 14.1′, 14.1″, and 14.2 extend into the interior of housing 1.2 through the signal output opening 1.22. The interior of housing 1.2 is the area surrounding the housing bottom 1.23.

[0175] The signal output opening 1.22 is closed to the outside by the protective cover 14.3 and the protective flange 14.3. Preferably, the end of the protective cover 14.3 is fastened to the protective flange 14.4. The protective flange 14.4 is made of a mechanically resistant material, such as metal or plastic. The fastening of the protective cover 14.3 and the protective flange 14.4 is achieved by force engagement, such as crimping.

[0176] The metal flange 14.4 is then securely fastened to the housing 1.2 by a material fit. Preferably, the metal flange 14.4 is fastened to the outer edge of the housing opening 1.22 facing away from the interior of the housing 1.2. This material fit is achieved by welding, brazing, bonding, etc. Fastening the protective flange 14.4 to the housing 1.2 results in stress relief of the protective cover 14.3. Due to the stress relief of the protective cover 14.3, the mechanical load from the protective cover 14.3 cannot be transmitted to the interior of the housing 1.2 and reach the converter unit 1.3, where it can cause damage, such as tearing or scratching of the base output conductors 13.8, 13.8′, 13.8″, and 13.9. This mechanical load originates from the rotation, twisting, etc., of the protective cover 14.3 about its long extension axis.

[0177] Figure 15The second assembly step is illustrated, wherein signal conductors 14.1, 14.1′, 14.1″, and 14.2 in the housing 1.2 are potted with potting material 14.6. The potting material 14.6 is applied through the housing opening 1.20 to the signal conductors 14.1, 14.1′, 14.1″, and 14.2 in the signal output opening 1.21. The potting material 14.6 is a chemically curable adhesive or a physically curable adhesive, or a combination of both. Preferably, the potting material 14.6 is made of an adhesive, such as an epoxide, polyurethane, cyanoacrylate, methyl methacrylate, etc. The potting material 14.6 has a density greater than 10. 12 Ωmm 2 An electrical insulator with a specific resistance of / m. Preferably, sufficient potting material 14.6 is applied to the signal conductors 14.1, 14.1′, 14.1″, and 14.2 in the signal output opening 1.21 to completely close the signal output opening 1.21.

[0178] Figure 16The third assembly step is illustrated, wherein signal conductors 14.1, 14.1′, 14.1″, and 14.2, encapsulated with potting material 14.6, are partially exposed within housing 1.2. The exposed portions 14.7 of the signal conductors 14.1, 14.1′, 14.1″, and 14.2 are achieved using a suitable cutting tool (e.g., a cutting wedge, milling cutter, etc.). The cutting tool enters the interior of housing 1.2 through housing opening 1.20 and cuts off the ends of 14.1, 14.1′, 14.1″, and 14.2 and the area of ​​hardened potting material 14.6. The exposed portions 14.7 are achieved in a plane expanded by the horizontal axis x and the vertical axis y. In the area of ​​the exposed portions 14.7, the end faces of the cut-off ends of the signal conductors 14.1, 14.1′, 14.1″, and 14.2 are exposed in a plane. Preferably, this plane extends parallel to housing opening 1.20. In the exposed area 14.7, the sides of signal conductors 14.1, 14.1′, 14.1″, and 14.2 are completely surrounded by potting material 14.6. The potting material 14.6 secures the signal conductors 14.1, 14.1′, 14.1″, and 14.2 with stress relief. Due to the stress relief of the signal conductors 14.1, 14.1′, 14.1″, and 14.2, mechanical loads from them cannot be transmitted into the interior of the housing 1.2 and reach the converter unit 1.3, where they could cause damage, such as tearing or ripping of the base output conductors 13.8, 13.8′, 13.8″, and 13.9. These mechanical loads originate from rotation, twisting, etc., of the signal conductors 14.1, 14.1′, 14.1″, and 14.2 about their long extension axes. Furthermore, the potting material 14.6 hermetically seals the signal output opening 1.21. This hermetically sealed signal output opening 1.21 prevents moisture from penetrating the interior of the housing 1.2 through the signal conductors 14.1, 14.1′, 14.1″, and 14.2 and reaching the sensor unit 1.1, where moisture could potentially impair the function of the piezoelectric elements 10, 10′, and 10″, as piezoelectric materials such as quartz are highly hygroscopic.

[0179] Figure 17 The fourth assembly step is shown, in which the sensor unit 1.1 is placed in the housing 1.2. The sensor unit 1.1, having a converter unit 1.3, is guided into the interior of the housing 1.2 through the housing opening 1.20. The second normal side 12.6 is secured to the bottom 1.23 of the housing by means of material fit, such as adhesive bonding or brazing. Preferably, the sensor unit 1.1 is oriented such that the fourth tangential side 12.4 is spatially close to the exposed portion 14.7.

[0180] Figure 18The fifth assembly step is shown, in which sensor unit 1.1 contacts converter unit 1.3. Contact with converter unit 1.3 is achieved by a suitable contact tool, such as wire bonding. The contact tool is guided into the interior of housing 1.2 through housing opening 1.20. The contact tool connects the first and second base conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″ of the converter unit 1.3 to the first side 130 of the first, second, or third piezoelectric element 10, 10′, 10″ via the first and second piezoelectric element conductors 13.1, 13.1′, 13.1″, 13.2, 13.2′, 13.2″. The contact tool also connects the first and second base conductors 13.3, 13.3′, 13.3″, 13.4, 13.4′, 13.4″ of the converter unit 1.3 to the signal conductors 14.1, 14.1′, 14.1″, 14.2 of the signal output terminal 1.4 via the first and second base output conductors 13.8, 13.8′, 13.8″, 13.9.

[0181] Preferably, the cut-off ends of the first and second substrate output conductors 13.8, 13.8′, 13.8″, 13.9 are in direct contact with the cut-off ends of the signal conductors 14.1, 14.1′, 14.1″, 14.2. This direct contact between the first and second substrate output conductors 13.8, 13.8′, 13.8″, 13.9 and the signal conductors 14.1, 14.1′, 14.1″, 14.2 has the advantage of eliminating the need for other supporting devices, such as circuit boards. This keeps the size and weight of the accelerometer small, and simplifies and reduces the cost of accelerometer assembly. Another advantage of the direct contact between the first and second substrate output conductors 13.8, 13.8′, 13.8″, 13.9 and the signal conductors 14.1, 14.1′, 14.1″, 14.2 is that the converter unit 1.3 contacts the signal conductors 14.1, 14.1′, 14.1″, 14.2 in a stress-relief manner through the mechanically flexible substrate output conductors 13.8, 13.8′, 13.8″, 13.9. This is because the mechanically flexible substrate output conductors 13.8, 13.8′, 13.8″, 13.9 reduce the mechanical load reaching the signal conductors 14.1, 14.1′, 14.1″, 14.2.

[0182] After the electrical contact converter unit 1.3 is closed, the housing opening 1.20 is hermetically sealed by the housing cover 1.21. This sealing is achieved by material fitting, such as welding, brazing, or bonding.

Claims

1. An acceleration sensor (1) having at least one piezoelectric element (10, 10′, 10″), at least one test block (11, 11′, 11″), and a substrate (12). The accelerometer (1) is arranged in a Cartesian coordinate system with three axes (x, y, z), wherein the three axes (x, y, z) include the horizontal axis (x), the vertical axis (y), and the vertical axis (z). The substrate (12) has tangential sides (12.1, 12.2, 12.3, 12.4) and normal sides (12.6, 12.7), the tangential sides (12.1, 12.2, 12.3, 12.4) being arranged tangentially relative to the vertical axis (z), and the normal sides (12.6, 12.7) being arranged normally relative to the vertical axis (z); Its features are, A piezoelectric element (10, 10′, 10″) is fastened to at least one tangential side (12.1, 12.2, 12.3). A test block (11, 11', 11") is fastened to the piezoelectric element (10, 10', 10″), and a shear force proportional to the acceleration is applied to the piezoelectric element (10, 10', 10″) during acceleration, the shear force acting along one of the three axes (x, y, z) that serve as the principal tangential axis (h); The piezoelectric element (10, 10′, 10″) has end faces (110, 120), each end face (110, 120) located in a plane formed by the principal tangential axis (h) and the secondary tangential axis (n), in which the secondary tangential axis (n) is perpendicular to the principal tangential axis (h) and has a normal axis (a) that is normal to the plane; Under the action of shear force along the main tangential axis (h), the piezoelectric element (10, 10′, 10″) generates piezoelectric charge on the end face (110, 120); During acceleration, a test block (11) fastened to the piezoelectric element (10, 10′, 10″) applies a shear force proportional to the acceleration along the secondary tangential axis (n) to the piezoelectric element (10, 10′, 10″), and the piezoelectric element (10, 10′, 10″) generates piezoelectric interference charge on its end face (110, 120) under the action of the shear force along the secondary tangential axis (n). The piezoelectric element (10, 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) intercepts piezoelectric charge against shear force along the main tangential axis (h); and the conductive end face coating (111, 121) intercepts piezoelectric interference charge against shear force along the secondary tangential axis (n); The piezoelectric element (10, 10′, 10″) has sides (130, 140, 150, 160) parallel to the normal axis (a). During acceleration, a test block (11, 11', 11') fastened to the piezoelectric element (10, 10', 10'') applies a normal force proportional to the acceleration along the normal axis (a) to the piezoelectric element (10, 10', 10''). Under the action of the normal force along the normal axis (a), the piezoelectric element (10, 10', 10'') generates piezoelectric interference charge on its end face (110, 120). The piezoelectric element (10, 10′, 10″) has at least one side (130, 140, 150, 160) with at least one conductive side coating (131, 133, 141, 151, 161) locally; and the conductive side coating (131, 133, 141, 151, 161) intercepts piezoelectric interference charges against normal forces along the normal axis (a).

2. The acceleration sensor (1) according to claim 1, characterized in that, The piezoelectric elements (10, 10′, 10″) are highly sensitive to shear forces along the principal tangential axis (h) exerted by the test block (11, 11′, 11″) fastened thereto. The piezoelectric elements (10, 10′, 10″) exhibit low sensitivity to shear forces along the secondary tangential axis (n) exerted by the test block (11, 11′, 11″) fastened thereto; and The piezoelectric element (10, 10′, 10″) has low sensitivity to the normal force along the normal axis (a) applied by the test block (11, 11′, 11″) fastened thereto.

3. The acceleration sensor (1) according to claim 1, characterized in that, The piezoelectric element (10) has high sensitivity to shear force along the longitudinal axis (y) which is the main tangential axis (h), low sensitivity to shear force along the vertical axis (z) which is the secondary tangential axis (n), and low sensitivity to normal force along the transverse axis (x) which is the normal axis (a). And / or the piezoelectric element (10′) has high sensitivity to shear force along the transverse axis (x) which is the main tangential axis (h), low sensitivity to shear force along the vertical axis (z) which is the secondary tangential axis (n), and low sensitivity to normal force along the longitudinal axis (y) which is the normal axis (a). And / or the piezoelectric element (10″) has high sensitivity to shear force along the vertical axis (z) which is the main tangential axis (h), low sensitivity to shear force along the longitudinal axis (y) which is the secondary tangential axis (n), and low sensitivity to normal force along the transverse axis (x) which is the normal axis (a).

4. The 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 high sensitivity to shear force along the main tangential axis (h) than with low sensitivity to shear force along the secondary tangential axis (n) or with low sensitivity to normal force along the normal axis (a).

5. The 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 the piezoelectric interference charge intercepted by the shear force along the secondary tangential axis (n) has the opposite polarity to the piezoelectric interference charge intercepted by the normal force along the normal axis (a).

6. The acceleration sensor (1) according to claim 5, characterized in that, For the piezoelectric element (10, 10′, 10″), the size of the conductive side coating (131, 133, 141, 151, 161) is adjustable; the size of the conductive side coating (131, 133, 141, 151, 161) is adjusted such that the piezoelectric interference charge intercepted by the continuous conductive coating (101, 102) for shear force along the secondary tangential axis (n) is substantially the same as the piezoelectric interference charge intercepted for normal force along the normal axis (a).

7. The acceleration sensor (1) according to claim 5, characterized in that, For the piezoelectric element (10, 10′, 10″), the sides (130, 140, 150, 160) include a first side (130) normal to the subtangential axis (n) of the piezoelectric element (10, 10′, 10″); the first side (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) is adjusted such that the piezoelectric interference charge intercepted by the continuous conductive coating (101, 102) for shear force along the subtangential axis (n) is substantially the same as the piezoelectric interference charge intercepted for normal force along the normal axis (a).

8. The acceleration sensor (1) according to claim 7, characterized in that, The accelerometer (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″); for the piezoelectric element (10, 10′, 10″), the first conductive side coating (131) is materially connected to the first piezoelectric element conductor (13.1, 13.1′, 13.1″); for the piezoelectric element (10, 10′, 10″), the additional first conductive side coating (133) is materially connected to the second piezoelectric element conductor (13.2, 13.2′, 13.2″); the first piezoelectric element conductor (13.1′, 13.1″) has a first conductive side coating (133′, 13.1″) and a second piezoelectric element conductor (13.2′, 13.1′, 13.2″); the first piezoelectric element conductor (13.1′, 13.1′, 13.2″) has a first conductive side coating (13.1′, 13.1′, 13.1″) and a second piezoelectric element conductor (13.2 ... 13.1, 13.1′, 13.1″) derive piezoelectric charge from the first continuous conductive coating (101) as a first acceleration signal (S1); and the second piezoelectric element conductor (13.2, 13.2′, 13.2″) derives piezoelectric charge from the second continuous conductive coating (102) as a second acceleration signal (S2).

9. The acceleration sensor (1) according to any one of claims 1 to 8, characterized in that, For the piezoelectric element (10, 10′, 10″), the conductive end-face coating (111, 121) is material-fitted onto the end faces (110, 120) and seals the tiny pores in the end faces (110, 120); the conductive side-face coating (131, 133, 141, 151, 161) is material-fitted onto the sides (130, 140, 150, 160) and seals the tiny pores in the sides (130, 140, 150, 160); and by sealing the tiny pores, the piezoelectric element (10, 10′, 10″) no longer requires mechanical preload.

10. The acceleration sensor (1) according to any one of claims 1 to 8, characterized in that, At least one piezoelectric element (10, 10′, 10″) has end faces (110, 120) including 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 relative to the normal axis (a) of the piezoelectric element (10, 10′, 10″); the first end face (110) has a first conductive end face coating (111); the second end face (120) has a second conductive end face coating (121); the side faces (130, 140, 150, 160) include a first side face. The first side surface (130) is normal to the secondary tangential axis (n) of the piezoelectric element (10, 10′, 10″); the first side surface (130) has a first conductive side coating (131) and another first conductive side coating (133); the first conductive end face coating (111) and the first conductive side coating (131) form a first continuous conductive coating (101); and the second conductive end face coating (121) and the other first conductive side coating (133) form a second continuous conductive coating (102).

11. The acceleration sensor (1) according to claim 10, characterized in that, The piezoelectric element (10, 10′, 10″) has sides (130, 140, 150, 160) including 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 principal 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 part of the second continuous conductive coating (102).

12. The acceleration sensor (1) according to claim 10, characterized in that, The piezoelectric element (10, 10′, 10″) has sides (130, 140, 150, 160) including 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 principal tangential axis (h) of the piezoelectric element (10, 10′, 10″); the second side (140) has a second conductive side coating (141); the third side (150) has a third conductive side coating (151); the third conductive side coating (151) is part of the first continuous conductive coating (101), and the second conductive side coating (141) is part of the second continuous conductive coating (102).

13. The acceleration sensor (1) according to claim 10, characterized in that, The piezoelectric element (10, 10′, 10″) has sides (130, 140, 150, 160) including at least one second side (140) and at least one fourth side (160), the second side (140) being normal to the principal tangential axis (h) of the piezoelectric element (10, 10′, 10″), and the fourth side (160) being normal to the secondary tangential axis (n) of the piezoelectric element (10, 10′, 10″); the second side (140) having a second conductive side coating (141); the fourth side (160) having a fourth conductive side coating (161); and the second conductive side coating (141) and the fourth conductive side coating (161) being part of the first continuous conductive coating (101) or part of the second continuous conductive coating (102).

14. The acceleration sensor (1) according to claim 10, characterized in that, The piezoelectric element (10, 10′, 10″) has sides (130, 140, 150, 160) including at least one third side (150) and at least one fourth side (160), the third side (150) being normal to the principal tangential axis (h) of the piezoelectric element (10, 10′, 10″) and the fourth side (160) being normal to the secondary tangential axis (n) of the piezoelectric element (10, 10′, 10″); the third side (150) has a third conductive side coating (151); the fourth side (160) has a fourth conductive side coating (161); the third conductive side coating (151) is part of the first continuous conductive coating (101), and the fourth conductive side coating (161) is part of the second continuous conductive coating (102).

Images