JP2013130433A - Sensor module, force detection device and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor module which is capable of equally applying pre-pressure to a sensor element, a force detection device and a robot.SOLUTION: A sensor module 10 comprises a sensor element 42 including a piezoelectric substance, a first member 12 accommodating the sensor element 42, a second member 34 which is joined to the first member 12 and seals the first member 12, a first plate 70 and a second plate 80 supporting the first member 12 and the second member 34 between them, and a fastening part 86 which fixes the first member 12 between the first plate 70 and the second plate 80 while pressurizing the first member 12. In the first plate 70, a first pressing part 72 is formed on a surface at a side of the first member 12, which protrudes toward the second member, and the second member 34 is held between the first pressing part 72 and a pressure receiving surface 44 of the sensor element 42.

Description

  The present invention relates to a sensor module, a force detection device, and a robot.

  Conventionally, the thing of patent document 1 was known as a force sensor using a piezoelectric material. As shown in FIG. 4 of Patent Document 1, the signal electrode 15 shown in FIG. 15 of Patent Document 1 is sandwiched by a crystal disk 16 that is a piezoelectric material, and is further sandwiched by a metal cover disk 17. A plurality of force sensors arranged by welding in the metal ring 14 is disclosed.

  FIG. 12 shows a conventional sensor device. As shown in FIG. 12, the sensor device 200 includes a sensor element 214 that sandwiches the electrode plate 218 with two crystal plates 216 having the same cut surface facing each other, and a metal device that houses the sensor element 214. The package 202 and the metal lid 204 that is bonded to the upper surface 224 that is the outer periphery of the opening 220 in the concave portion of the package 202 and that abuts on the crystal plate 216 constitute the whole. A coaxial connector 206 is attached to the side surface of the package 202. The coaxial connector 206 has an outer peripheral portion 208 and a center conductor 210, and an insulating resin 212 is filled between them, so that the outer peripheral portion 208 and the central conductor 210 are electrically insulated. The outer peripheral portion 208 is short-circuited with the package 202 and the lid 204, and the central conductor 210 is electrically connected to the electrode plate 218.

  The sensor device 200 is sandwiched between pressurization plates (not shown) and given pressurization, and the crystal plate 216 outputs (induces) electric charges to the electrode plate 218 due to the piezoelectric effect accompanying the pressurization. Then, the pressure applied to the crystal plate 216 changes according to the external force applied to the pressurizing plate. Therefore, the external force applied to the sensor device 200 can be detected by monitoring the change amount of the output charge due to the change in pressure through the coaxial connector 206.

  Here, in the sensor device 200, the lid 204 is used to detect the sensor in a state where the inside of the package 202 is filled with dry air or a vacuum is maintained so that the charge induced from the crystal plate 216 does not leak to the outside due to moisture or the like. The element 214 is sealed.

Japanese Unexamined Patent Publication No. Hei 4-231827

  The force sensor disclosed in Patent Document 1 has a structure in which a signal electrode is sandwiched between crystal disks and this crystal disk is sandwiched between metal cover disks. When this is attached to the metal ring by welding, there is a dimensional error in individual parts such as signal electrodes, which becomes unevenness in the welded portion, and there is a possibility that a gap is generated in the welding. Therefore, in a situation where the external environment is inferior, such as high humidity, there is a possibility that the charge leaks to the outside due to the intrusion of moisture into the sensor element, making stable measurement difficult. Further, the method of sealing the measuring element by laser welding or the like is a complicated process and has a problem that it is difficult to apply to mass production.

  Further, the conventional sensor device shown in FIG. 12 has the following problems when the sensor element is accommodated in the package. In the manufacturing process of the package and the sensor element, the package has a dimensional error of several tens of μm, and the sensor element has a dimensional error of several μm, resulting in manufacturing variations based on such a dimensional error. For this reason, it has been difficult to accurately adjust the internal height of the package (the height from the package mounting surface to the lid) and the height of the sensor element.

  13A and 13B are explanatory views of a conventional sensor device in which manufacturing variation has occurred. FIG. 13A shows a case where the upper surface of the sensor element is lower than the position of the outer periphery of the opening of the recess of the package, and FIG. The case where the upper surface of an element becomes higher than the position used as the outer periphery of the opening part of the recessed part of a package is shown.

  As shown in FIG. 13A, when the height of the upper surface 222 of the sensor element 214 is lower than the height of the upper surface 224, the lid 204 and the upper surface 222 of the sensor element 214 are joined when the lid 204 is joined to the package 202. A gap 226 is formed without contact. 13B, when the height of the upper surface 222 of the sensor element 214 is higher than the height of the upper surface 224 that is the outer periphery of the opening 220 of the recess of the package 202, the lid 204 is bonded to the package 202. Then, as shown in FIG. That is, the center portion of the lid 204 is raised, and the periphery of the upper surface 222 of the sensor element 214 contacts the lid 204, but a gap 228 is formed between the center portion of the upper surface 222 of the sensor element 214 and the lid 204. Is done.

  Thus, when the upper surface of the sensor element is lower than the position that is the outer periphery of the opening of the recess of the package, the upper surface of the sensor element is higher than the position that is the outer periphery of the opening of the recess of the package. When applying a pressurizing pressure using a plurality of any one of the sensor devices that coincides with the position of the outer periphery of the opening of the concave portion of the package, it is difficult to apply the pressure evenly.

  Further, it is necessary to apply a pressure (usually about 10 kN) to the sensor element in advance. However, in the conventional sensor device, it is difficult to apply a sufficient pressure depending on the package sealing technique.

  Therefore, in order to solve the above-described problems of the prior art, the present invention can perform high-precision force detection by preloading the sensor elements evenly while ensuring airtightness of the sensor elements accommodated in the package. The purpose is to provide a sensor module, a force detection device, and a robot.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples.

Application Example 1 A sensor module according to this application example includes a sensor element having a piezoelectric body, a first member on which the sensor element is disposed, and a second member that is bonded to the first member and seals the first member. A member, a first plate and a second plate for supporting the first member and the second member between the plates, and a fastening portion for fixing the first member between the first plate and the second plate. The first plate is formed with a first pressing portion projecting toward the second member on a surface on the first member side, and the second member is a pressure receiving surface of the first pressing portion and the sensor element. It is characterized by being pinched by.
With the above configuration, a pressure can be applied to the sensor element from the outside of the first member via the second member with respect to the sensor device in which the sensor element is sealed in the first member. Further, due to a dimensional error of the sensor device, for example, even if the sensor element accommodated in the first member is not in contact with the second member, the first pressing portion can sufficiently apply a pressure to the sensor element. it can. For this reason, it is possible to always apply a constant pressurization to the sensor element regardless of manufacturing variations of the sensor device, and it is possible to obtain accurate detection data with no measurement error. Therefore, the yield of the sensor module is improved.

Application Example 2 The first pressing portion has a surface that overlaps with the entire area of the pressure receiving surface of the sensor element in a plan view, and is positioned inside an inner peripheral region of the first member in a plan view. The sensor module according to Application Example 1, wherein the fastening portion fixes the first member between the first plate and the second plate while applying pressure.
With the above configuration, the first pressing portion can always apply a uniform pressure to the entire area of the upper surface of the sensor element. Therefore, accurate detection data with no measurement error can be obtained.

[Application Example 3] In the application example 1 or 2, the second plate is formed on the surface on the first member side so that the second pressing portion faces the first pressing portion. Sensor module.
With the above configuration, the connection wiring can be drawn from the external terminal on the mounting surface of the first member. Further, it is possible to efficiently apply a pressure from the upper and lower surfaces of the sensor element. Furthermore, a gap between the first plate and the second plate can be widened, and a space for installing wiring, a control circuit (IC) and the like can be secured.

Application Example 4 The sensor module according to Application Example 3, wherein a recess that fits with the second pressing portion is formed on the mounting surface of the first member.
Thereby, the first member and the second plate can be easily and reliably aligned.

Application Example 5 The second member has an annular flexible portion formed outside the pressure-receiving surface of the sensor element in a plan view and inside an inner peripheral region of the first member in a plan view. The sensor module according to any one of Application Examples 1 to 4, which is a feature.
With the above configuration, even when the heights of the first member and the sensor element do not match, the second member is not stressed by the deformation of the flexible portion of the second member by the pressure applied by the first pressing portion. The joined state of the first member and the second member can be maintained and kept airtight.

Application Example 6 When the stacking direction of the sensor elements in which a plurality of the piezoelectric bodies are stacked is the Z-axis direction, the directions perpendicular to the Z-axis direction and perpendicular to each other are defined as the X-axis direction and the Y-axis direction, respectively. A first sensor element that detects at least the force in the X-axis direction, a second sensor element that detects the force in the Y-axis direction, and a third sensor element that detects the force in the Z-axis direction. The sensor module according to any one of Application Examples 1 to 5, wherein
Even if it is a sensor device which detects the force of a triaxial direction by controlling the mutual position shift of the sensor element which detects the force of X direction, Y direction, Z direction, and what is called a triaxial direction by the above-mentioned composition. It can be stably maintained without impairing high detection accuracy.

Application Example 7 A force detection device comprising the sensor module according to any one of Application Examples 1 to 6.
With the above configuration, the external force load can be easily calculated and measured based on the amount of charge and the sign of the charge. In addition, a triaxial force detection sensor can be obtained with a simple configuration. Furthermore, by using a plurality of sensor modules according to the application examples described above, for example, a six-axis force detection device including torque measurement can be easily obtained. .

Application Example 8 A robot including the force detection device according to Application Example 7.
With the above configuration, the detection of contact with obstacles and the contact force with the object that occur during a specified operation for the robot arm or robot hand that operates is detected reliably by the force detection device, and data is sent to the robot control device. By feeding back, safe and detailed work can be performed.

Application Example 9 A robot including a main body portion, an arm connected to the main body portion, and a hand portion connected to the arm portion, wherein a sensor module is provided at a connection portion between the arm portion and the hand portion. The sensor module includes a sensor element having a piezoelectric body, a first member on which the sensor element is disposed, and a second member that is bonded to an end surface of a side wall of the first member and seals the first member. And a first plate and a second plate that support the first member and the second member between the plates, and a fastening portion that fixes the first member between the first plate and the second plate, The first plate has a first pressing portion projecting toward the second member on a surface on the first member side, and the second member is formed by the first pressing portion and a pressure receiving surface of the sensor element. This is pinched Robot characterized by.
With the above configuration, the detection of contact with obstacles and the contact force with the target that occur during the specified operation for the operating robot arm or robot hand is reliably detected by the force detection device, and the data is sent to the robot control device. By feeding back, safe and detailed work can be performed. In addition, the robot can stably detect a highly accurate force even with a small amount of change.

It is sectional drawing of the sensor module which concerns on 1st Embodiment. It is a top view from the element lamination direction of the sensor device (a 2nd member is omitted) of this embodiment. It is a top view from the element lamination direction of the base member of this embodiment. It is a top view of the 2nd member of this embodiment. It is a schematic diagram of the sensor element of this embodiment. It is explanatory drawing of the sensor device which the clearance gap produced between the sensor element and the 2nd member, (a) is sectional drawing of a sensor device, (b) is sectional drawing of the sensor device which applied the pressurization. It is sectional drawing of the sensor module which concerns on 2nd Embodiment. It is sectional drawing of the sensor module which concerns on 3rd Embodiment. It is sectional drawing of the sensor module which concerns on 4th Embodiment. The force detection apparatus of this embodiment is shown, (a) shows a schematic diagram, (b) shows a top view. It is a schematic diagram of the robot carrying the force detection apparatus of this embodiment. It is a schematic diagram of the sensor device of a prior art. It is explanatory drawing of the sensor device in which the manufacture dispersion | variation produced conventionally, (a) shows the case where the upper surface of a sensor element becomes lower than the position used as the outer periphery of the opening part of the recessed part of a 1st member, (b) is a sensor element The case where the upper surface of is higher than the position that becomes the outer periphery of the opening of the recess of the first member is shown.

Embodiments of a sensor module, a force detection device, and a robot of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a sectional view of a sensor module according to the first embodiment. FIG. 2 is a plan view from the element stacking direction of the sensor device of the present embodiment (the second member is omitted). FIG. 3 is a plan view of the base member of this embodiment from the element stacking direction.

  The sensor module 10 according to the first embodiment includes a sensor device 11 in which a sensor element capable of detecting a force component is sealed in a first member, a first plate 70 that supports the sensor device 11 so as to be sandwiched between the plates, The second basic plate 80 and the fastening portion 86 that fixes the sensor device between the first plate and the second plate while applying pressure are the main basic components. First, the sensor device 11 of the present embodiment has the first basic member 12, the second member 34, and the sensor element 42 as the main basic configuration.

  The first member 12 includes a base member 14 and a side wall member 24, both of which are formed of an insulating material such as ceramic. In this embodiment, ceramics or the like is used for the base member 14 and the side wall member 24. However, the material is not particularly limited as long as it is an insulating material, and the base member 14 and the side wall member 24 are respectively Different materials may be used. The base member 14 is a flat plate having a rectangular shape in plan view, and the sensor element 42 is disposed on the upper surface. The side wall member 24 has the same outer shape as the base member 14 in plan view (FIG. 2), and is disposed on the base member 14 so as to surround the sensor element 42 (ring shape).

  As shown in FIG. 3, a ground electrode 16 connected to the lower surface of the sensor element is disposed at the center of the upper surface of the base member 14. Further, side electrodes 20A, 20B, 20C, and 20D are arranged at the four corners of the lower surface of the base member 14. The side electrodes 20A, 20B, 20C, and 20D are electrically connected to mounting electrodes on an electronic circuit board (not shown), respectively.

  As shown in FIGS. 1, 2, and 3, connection electrodes 18 </ b> A, 18 </ b> B, 18 </ b> C, and 18 </ b> D are disposed on the upper surface of the base member 14. The connection electrodes 18A, 18B, 18C, and 18D are arranged corresponding to the side electrodes 20A, 20B, 20C, and 20D, respectively, and one end thereof is at a position facing the side electrodes 20A, 20B, 20C, and 20D in plan view. Has been placed. On the other hand, the other ends of the connection electrodes 18A, 18B, and 18C are arranged at positions near the ground electrode 16. The other end of the connection electrode 18D is connected to the ground electrode 16.

  As shown in FIG. 2, the side wall member 24 is laminated at a position on the base member 14. The side wall member 24 is disposed so as to cover the connection electrodes 18A, 18B, 18C, and 18D, but the other end side of the connection electrodes 18A, 18B, 18C, and 18D is exposed inside the side wall member 24, and the ground electrode 16 is also formed. The base member 14 is laminated in an exposed state. Further, as shown in FIG. 1, a metallized 26 is disposed on the upper surface of the side wall member 24, and this becomes the end surface 32 of the first member 12. As shown in FIGS. 1 and 2, a through electrode 28 penetrating the side wall member 24 in the height direction is disposed at a position facing the connection electrode 18D of the side wall member 24, and the metallized 26, the connection electrode 18D, Are electrically connected through the through electrode 28.

  Accordingly, as shown in FIGS. 1 and 2, in the first member 12, the opening 30 of the concave portion of the first member 12 is formed by the side wall member 24, and the opening is formed by the end surface 32 of the side wall member 24 on which the metallized 26 is disposed. An outer peripheral surface serving as an outer periphery of the portion 30 is formed. The ground electrode 16 and the connection electrodes 18A, 18B, 18C, and 18D are formed of a metal having conductivity, and the metallized 26 can be formed of the same material as the ground electrode 16 and the like.

  FIG. 4 shows a plan view of the second member of the present embodiment. As shown in FIGS. 1 and 4, the second member 34 is formed in a substantially rectangular shape (a shape that is the same as the side wall member 24 in a plan view) from a metal such as stainless steel or Kovar. And the position which overlaps with the side wall member 24 by planar view of the 2nd member 34 becomes a rectangular ring-shaped peripheral part 38, and the inner side of the peripheral part 38 is the force transmission part 36. FIG. The second member 34 of the present embodiment can be formed by press molding or etching. The force transmitting portion 36 is in surface contact with the entire force receiving surface 44 of the sensor element 42 in a state where a pressure is applied by a first plate 70 described later.

  As shown in FIG. 1, the peripheral edge 38 is joined to the metallized layer 26 that forms the end face 32 of the side wall member 24 by seam welding. The seam welding is performed in a dry atmosphere or a vacuum atmosphere, and the sensor element 42 is hermetically sealed in the first member 12 by seam welding between the second member 34 and the metallized 26. Here, the second member 34 is electrically connected to the connection electrode 18 </ b> D via the metallization 26 and the through electrode 28.

As shown in FIG. 1, the sensor element 42 is formed of, for example, quartz, lead zirconate titanate (PZT: Pb (Zr, Ti) O ₃ ), lithium niobate, lithium tantalate or the like having piezoelectricity. In this embodiment, a quartz plate is used as the piezoelectric body. The sensor element 42 is formed by laminating a first sensor element 46, a third sensor element 58, and a second sensor element 52 in order from the top. The first sensor element 46 is formed such that the first quartz plates 48A and 48B sandwich the first detection electrode 50. The second sensor element 52 is formed such that the second crystal plates 54 </ b> A and 54 </ b> B sandwich the second detection electrode 56. The third sensor element 58 is formed so that the third crystal plates 60 </ b> A and 60 </ b> B sandwich the third detection electrode 62.

  A first ground electrode 64 serving as an electrode is disposed between the first sensor element 46 (first crystal plate 48B) and the third sensor element 58 (third crystal plate 60A), and the third sensor element 58 ( A second ground electrode 66 is disposed between the third crystal plate 60B) and the second sensor element 52 (second crystal plate 54A). Further, the upper surface of the first sensor element 46 (first crystal plate 48A) is a pressure receiving surface 44 of the sensor element 42, and is in surface contact with the force transmitting portion 36 of the second member 34 and grounded. The lower surface of the second sensor element 52 (second crystal plate 54B) is grounded by being connected to the ground electrode 16.

  As shown in FIG. 2, the first detection electrode 50, the second detection electrode 56, the third detection electrode 62, the first ground electrode 64, and the second ground electrode 66 are formed from stacked first to third crystal plates. Each part is arranged so that it protrudes. The first detection electrode 50 is connected to an exposed portion (the other end side) of the connection electrode 18A by a conductive wire 68A. The second detection electrode 56 is connected to the exposed portion (the other end side) of the connection electrode 18B by a wire 68B. The third detection electrode 62 is connected to the exposed portion (the other end side) of the connection electrode 18C by a wire 68C. The first ground electrode 64 and the second ground electrode 66 are connected to the exposed portion (the other end side) of the connection electrode 18D by wires 68D and 68E, respectively.

  By the above connection, the side electrode 20A is electrically connected to the first detection electrode 50 via the connection electrode 18A and the wire 68A. The side electrode 20B is electrically connected to the second detection electrode 56 through the connection electrode 18B and the wire 68B. The side electrode 20C is electrically connected to the third detection electrode 62 through the connection electrode 18C and the wire 68C.

  Further, the side electrode 20D is electrically connected to the ground electrode 16 through the connection electrode 18D. Further, the side electrode 20D is electrically connected to the first ground electrode 64 via a wire 68D connected to the connection electrode 18D, and is electrically connected to the second ground electrode 66 via a wire 68E connected to the connection electrode 18D. It is connected and electrically connected to the second member 34 through the through electrode 28 and the metallized 26 connected to the connection electrode 18D.

  As the materials for the various electrodes described above, a simple substance or an alloy such as gold, titanium, aluminum, copper, or iron can be used. For example, stainless steel can be used as the iron alloy, and it is preferably used because of its excellent durability and corrosion resistance.

  FIG. 5 shows a schematic diagram of the sensor element of the present embodiment. In the present embodiment, the force transmission unit 36 applies not only the force in the direction parallel to the normal direction (γ axis) of the pressure receiving surface 44 of the sensor element 42 but also the force in the surface direction of the pressure receiving surface 44, that is, the γ axis. Forces in two directions (α axis and β axis) that are orthogonal and orthogonal to each other can be transmitted to the pressure receiving surface 44. The sensor element 42 can detect forces parallel to the α-axis, β-axis, and γ-axis, as will be described later.

  In the first sensor element 46, the first crystal plates 48A and 48B are formed of Y-cut crystal plates, and the X direction, which is the crystal orientation for generating the piezoelectric effect, is normal to the first crystal plates 48A and 48B (FIG. 5). The crystal orientation is perpendicular to the direction parallel to the γ-axis. The first crystal plates 48A and 48B are arranged so that the X directions are opposite to each other. Furthermore, the first crystal plates 48A and 48B are arranged so that the X direction is parallel to the α axis of the space orthogonal coordinates.

  In the second sensor element 52, the second crystal plates 54A and 54B are formed of Y-cut crystal plates, and the X direction is perpendicular to the normal line (the direction parallel to the γ axis) of the second crystal plates 54A and 54B. The crystal orientation is as follows. The second crystal plates 54A and 54B are arranged so that the X directions are opposite to each other. Further, the second crystal plates 54A and 54B are arranged so that the X direction is parallel to the β-axis of the space orthogonal coordinates.

  In the third sensor element 58, the third crystal plates 60A and 60B are formed by X-cut crystal plates, and the X direction is parallel to the normal line (the direction parallel to the γ axis) of the third crystal plates 60A and 60B. The crystal orientation is as follows. The third crystal plates 60A and 60B are arranged so that the X directions are opposite to each other. Furthermore, the third crystal plates 60A and 60B are arranged so that the X direction is parallel to the γ-axis of the space orthogonal coordinates.

  As shown in FIG. 5, the sensor element 42 of the present embodiment has a direction parallel to the γ-axis of the space orthogonal coordinates as the height direction of the sensor element 42. Then, the first plate 70 and the second plate 80, which will be described later, are sandwiched from the direction of the γ-axis and given pressure, and the pressure is applied to the sensor element 42 from the direction parallel to the γ-axis via the first pressing portion 72. Is done. As a result, the third crystal plates 60A and 60B receive pressure (compression force) from the X direction, so that charge is induced by the piezoelectric effect, and charge (Fz signal) is output to the third detection electrode 62.

  In the above configuration, when an external force is applied in which the relative positions of the first plate and the second plate (see FIG. 10) are shifted in the direction parallel to the α axis, the sensor element 42 is connected to the sensor element 42 via the first pressing portion 72. An external force in a direction parallel to the α axis is applied. Then, since the first quartz plates 48A and 48B receive external force (shearing force) from the X direction, charges are induced by the piezoelectric effect, and charges (Fx signal) are output to the first detection electrode 50.

  Further, when an external force is applied in which the relative positions of the first plate and the second plate (see FIG. 10) are shifted in the direction parallel to the β axis, the sensor element 42 is moved to the β axis via the first pressing portion 72. An external force in a parallel direction is applied. Then, since the second crystal plates 54A and 54B receive external force (shearing force) from the X direction, electric charges are induced by the piezoelectric effect, and electric charges (Fy signals) are output to the second detection electrodes 56.

  Further, when an external force is applied in which the relative positions of the first plate and the second plate (see FIG. 10) are shifted from each other in the direction parallel to the γ-axis, the sensor element 42 is moved to the γ-axis via the first pressing portion 72. An external force in a parallel direction is applied. Then, since the third crystal plates 60A and 60B receive an external force (compression force or tensile force) from the X direction, the amount of charge induced by the piezoelectric effect changes, and the charge output to the third detection electrode 62 ( The magnitude of the (Fz signal) changes.

  Therefore, the sensor device 11 of the present embodiment outputs the charge (Fx signal) output to the first detection electrode 50 via the side electrode 20A and the second detection electrode 56 via the side electrode 20B. The charge (Fy signal) and the charge (Fz signal) output to the third detection electrode 62 via the side electrode 20C can be monitored, respectively, an α axis (X-axis described later) orthogonal to each other, External forces (Fx, Fy, Fz) in a direction parallel to the β axis (Y-axis described later) and the γ-axis (Z axis described later) can be detected. The sensor element 42 has a laminated structure of the first sensor element 46, the second sensor element 52, and the third sensor element 58, but may be configured to use at least one of them.

  In such a manufacturing method of the sensor device 11, the sensor element 42 is first placed on the base member 14, and then the peripheral portion 38 of the second member 34 is aligned with the end surface 32 of the side wall member 24 of the first member 12. To place. Then, a weight is disposed in the center of the second member 34 and a load is applied to the second member 34. Then, the roller electrode is pressed against the connection position of the second member 34 with the metallization 26 (side wall member 24), and an electric current is applied to the roller electrode 74 to join the second member 34 and the metallization 26 by seam welding. .

  The first plate 70 of the present embodiment is a substantially rectangular plate plate that is larger than the first member 12 in plan view. The first plate 70 is made of a metal material such as stainless steel, and has a predetermined strength and can be easily formed. The first plate 70 has a convex first pressing portion 72 that protrudes toward the second member 34 on the surface on the first member 12 side. The first pressing portion 72 includes a pressing surface 73 that overlaps with the entire region of the pressure receiving surface 44 of the sensor element 42 in a plan view and fits inside the region of the inner peripheral edge of the first member 12. In other words, the area of the pressing surface 73 is equal to or larger than the area of the upper surface of the sensor element 42 and smaller than the area of the inner peripheral edge of the first member. The first pressing portion 72 can be formed by pressing or etching. The first plate 70 is formed with a through hole 74 into which a fastening portion 86 described later is inserted. The through hole 74 includes a first hole 74A into which the head of the fastening portion 86 is inserted, and a second hole 74B into which the shaft is inserted.

  The second plate 80 is a plate plate that is larger than the first member 12 in plan view and has substantially the same shape as the first plate 70. The second plate 80 is formed with a screw hole 82 into which a male screw of a fastening portion 86 described later is screwed. The second plate 80 is made of a metal material such as stainless steel and has a predetermined strength and can be easily formed. Note that the first plate 70 and the second plate 80 may be formed in a disk, an ellipse, or a polygon in addition to a rectangular shape in plan view.

  The fastening portion 86 is a member that fastens the first plate 70 and the second plate 80 in a state where the sensor device 11 is sandwiched between the first plate 70 and the second plate 80. The fastening part 86 of this embodiment is a fastening bolt. The fastening bolt is composed of a head and a shaft. The tip of the shaft is formed with a threaded male screw and can be screwed into the screw hole 82 of the second plate 80. Such a fastening portion 86 only needs to be able to fix the sensor device 11 between the first plate 70 and the second plate 80 while applying pressure. In this embodiment, the fastening device 86 is installed at two locations so as to sandwich the sensor device 11 as an example. doing.

  In assembling the sensor module 10, the sensor device 11 is first placed on the second plate 80. Then, the first plate 70 is disposed on the sensor device 11 such that the first pressing portion 72 and the upper surface of the sensor element 42 of the sensor device 11 overlap in plan view. Next, a fastening bolt to be the fastening portion 86 is inserted from the through hole 74 of the first plate 70 and screwed into the screw hole 82 of the second plate 80. At this time, the tightening amount of the fastening portion 86 can be adjusted so that a predetermined pressurizing pressure (for example, about 10 kN) is applied.

  According to the sensor module having such a configuration, the sensor element 42 is sealed from the outside of the first member 12 via the first pressing portion 72 with respect to the sensor device 11 in which the sensor element 42 is sealed in the first member 12. A predetermined pressurizing pressure can be applied.

  6A and 6B are explanatory views of the sensor device in which a gap is generated between the sensor element and the second member. FIG. 6A is a cross-sectional view of the sensor device, and FIG. 6B is a cross-sectional view of the sensor device to which a pressure is applied. . As shown in FIG. 6A, the sensor device 11 in which a gap is generated between the pressure receiving surface 44 of the sensor element 42 and the second member 34 due to manufacturing variation based on the dimensional error of the sensor element 42 or the first member 12 is manufactured. May be. Even in such a sensor device, the pressure receiving surface 44 of the sensor element 42 is moved from the outside of the first member 12 by the first pressing portion 72 of the first plate 70 of the present embodiment as shown in FIG. It can be easily applied at a predetermined pressure.

  Thus, in the sensor module of the present embodiment, when the upper surface of the sensor element is lower than the position of the outer periphery of the opening of the recess of the first member, the upper surface of the sensor element is the outer periphery of the opening of the recess of the first member. The sensor element can be used for any sensor device that has a manufacturing variation such as when the upper surface of the sensor element coincides with the position of the outer periphery of the opening of the recess of the first member. A constant pressurization can always be applied, and accurate detection data free from measurement errors can be obtained. Therefore, the yield of the sensor module is improved. Furthermore, since the sensor element inside the first member can be protected even when used in an environment exposed to a liquid such as lubricating oil, water or chemicals, a highly reliable sensor module is obtained. Can do.

  FIG. 7 is a cross-sectional view of the sensor module according to the second embodiment. The sensor module 10A according to the second embodiment includes external electrodes 21A, 21B, 21C, and 21D, through electrodes 22A, 22B, 22C, and 22D, and a second pressing portion 84. The other configuration is the same as that of the sensor module 10 of the first embodiment, and the same reference numerals are given and detailed description is omitted. External electrodes 21 </ b> A, 21 </ b> B, 21 </ b> C, and 21 </ b> D are arranged at the four corners of the lower surface of the base substrate 14. The external electrodes 21A, 21B, 21C, and 21D are disposed corresponding to the connection electrodes 18A, 18B, 18C, and 18D, respectively, and are electrically connected through the through electrodes 22A, 22B, 22C, and 22D that penetrate the base substrate. ing.

  In the second plate 80A, a second pressing portion 84 having substantially the same shape as the first pressing portion 72 is formed on the mounting surface on which the sensor device 11 is mounted. The second pressing portion 84 includes a pressing surface 85 that is smaller than the mounting surface of the first member 12 in plan view and has an area equal to or larger than the area of the lower surface of the sensor element 42.

  According to the sensor module 10 </ b> A according to the second embodiment having such a configuration, it is possible to apply a pressure to the sensor element 42 of the sensor device 11 evenly and effectively from the upper and lower surfaces. In addition, since gaps are formed between the external electrodes 21A, 21B, 21C, and 21D formed on the mounting surface of the sensor device 11 and the second plate 80A, the metal wiring can be easily pulled out, and an external electronic circuit It can be easily electrically connected to the substrate.

  FIG. 8 is a cross-sectional view of a sensor module according to the third embodiment. In the sensor module 10 </ b> B according to the third embodiment, the concave portion 15 in which the second pressing portion 84 is fitted is formed on the lower surface of the first member 12. The other configuration is the same as that of the sensor module 10A of the second embodiment, and the same reference numerals are given and detailed description is omitted.

  The recess 15 of the present embodiment is a mounting surface of the base member 14 of the first member 12 and is formed at a position facing the lower surface of the sensor element 42. The concave portion 15 can be formed by etching or the like so as to have a downward concave shape into which the second pressing portion 84 is fitted.

  According to the sensor module 10B according to the third embodiment having such a configuration, the center of the sensor element 42 placed on the base member 14 and the center of the second pressing portion 84 of the second plate 80A are the same in plan view. It can be easily positioned so as to be in a straight line. Therefore, it is possible to apply a uniform pressure to the sensor element 42.

  FIG. 9 is a cross-sectional view of a sensor module according to the fourth embodiment. In the sensor module 10C of the fourth embodiment, the flexible portion 40 is formed on the second member 34A. Other configurations are the same as those of the sensor module 10 of the first embodiment, and detailed description thereof is omitted. .

  The flexible portion 40 is formed in a ring shape between the peripheral portion 38 of the second member 34A and the force transmitting portion 36 in plan view. The flexible portion 40 is arranged so that the periphery of the pressure receiving surface 44 of the sensor element 42 is accommodated in the inner periphery thereof in plan view. The flexible portion 40 is formed so that its thickness is thinner than that of the force transmitting portion 36 and the peripheral portion 38 in a state where the flexible portion 40 is dug from only one side or both sides of the second member 34A. The flexible portion 40 can be formed by press molding or etching.

In the sensor module 10C according to the fourth embodiment having such a configuration, even when the heights of the first member 12 and the sensor element 42 do not coincide with each other due to manufacturing variations based on dimensional errors, the first pressing portion 72 applies pressure to the sensor module 10C. By deforming the flexible portion 40 of the two members 34A, no stress is applied to the second member 34A, the joint between the first member 12 and the second member 34A is not broken, and the inside of the first member 12 is airtight. Can be kept in.
The flexible portion 40 may be applied to the second member of the sensor module according to the second and third embodiments.

  FIG. 10 shows the force detection device of this embodiment, (a) shows a schematic diagram, and (b) shows a plan view. The force detection device 90 of the present embodiment has a configuration in which four sensor devices 11 are sandwiched between a first plate 70A and a second plate 80A. Each of the first plate 70A and the second plate 80A is formed in a disk shape in plan view, and the four sensor devices 11 are arranged on lines that pass through the center and are orthogonal to each other. The first plate 70 </ b> A has four first pressing portions 72 formed at locations facing the upper surface of the sensor element 42 of the sensor device 11.

  The force detection device 90 having such a configuration is sandwiched between the first plate 70A and the second plate 80A in a state where all of the four sensor devices 11 face in the same direction, and pressure is applied. For example, in the sensor module 10, the detection axis of the first sensor element 46 (FIGS. 1 and 5) is oriented in a direction parallel to Fx, and the detection axis of the second sensor element 52 (FIGS. 1 and 5) is parallel to Fy. The detection axis of the third sensor element 58 (FIGS. 1 and 5) is directed in a direction parallel to Fz. It should be noted that the height of the sensor element of each sensor module 10 is measured in advance, and the projection amount of the first pressing portion 72 is adjusted by polishing or the like based on this measured value, thereby causing manufacturing variations of the sensor devices 11. Even in this case, it is possible to apply the pressure evenly while maintaining the parallelism between the first plate 70A and the second plate 80A.

  Here, when receiving a force in which the relative positions of the first plate 70A and the second plate 80A are shifted in the Fx direction, the sensor module 10 detects the forces of Fx1, Fx2, Fx3, and Fx4, respectively. In addition, when the relative position of the first plate 70A and the second plate 80A receives a force that shifts in the Fy direction, the sensor module 10 detects the forces of Fy1, Fy2, Fy3, and Fy4, respectively. Further, when receiving a force in which the relative positions of the first plate 70A and the second plate 80A are shifted from each other in the Fz direction, the sensor module 10 detects the forces of Fz1, Fz2, Fz3, and Fz4, respectively.

  Therefore, in the force detection device 90, the rotational force Mx is set to a direction parallel to the forces Fx, Fy, Fz, and Fx orthogonal to each other, and the rotational force My and Fz is set to be parallel to the direction parallel to Fy. The rotational force Mz whose direction is the rotation axis can be obtained as follows.

  Here, a and b are constants. Therefore, the force detection device 90 according to the present embodiment can detect forces from all three dimensions (forces in six axes) and stably detect highly accurate forces even with a small amount of displacement. The force detection device 90 can be performed.

  FIG. 11 shows a robot equipped with the force detection device of this embodiment. As shown in FIG. 11, the robot 100 includes a main body 102, an arm 104, a robot hand 116, and the like. The main body 102 is fixed on, for example, a floor, a wall, a ceiling, or a movable carriage. The arm unit 104 is provided so as to be movable with respect to the main body unit 102. The main body unit 102 includes an actuator (not shown) that generates power for rotating the arm unit 104, and a control for controlling the actuator. Etc. (not shown) are incorporated.

  The arm unit 104 includes a first frame 106, a second frame 108, a third frame 110, a fourth frame 112, and a fifth frame 114. The first frame 106 is connected to the main body 102 so as to be rotatable or bendable via a rotating and bending shaft. The second frame 108 is connected to the first frame 106 and the third frame 110 via a rotating and bending shaft. The third frame 110 is connected to the second frame 108 and the fourth frame 112 via a rotating and bending shaft. The fourth frame 112 is connected to the third frame 110 and the fifth frame 114 via a rotating and bending shaft. The fifth frame 114 is connected to the fourth frame 112 via a rotating and bending shaft. The arm unit 104 is driven by each frame being rotated or bent in a compound manner around each rotation / bending axis under the control of the control unit.

  A robot hand unit 116 is attached to the tip of the fifth frame 114, and the robot hand 120 capable of grasping an object is connected via a robot hand connection unit 118 having a built-in motor (not shown) that rotates. Connected to the fifth frame 114.

  In addition to the motor, the robot hand connection unit 118 incorporates the aforementioned force detection device 90 (not shown in FIG. 11). When the robot hand unit 116 is moved to a predetermined operation position by the control of the control unit. , Contact with an obstacle or contact with an object by an operation command beyond a predetermined position is detected as a force by the force detection device 90 and fed back to the control unit of the robot 100 to execute an avoidance operation. Can do.

  By using such a robot 100, it is possible to easily perform an obstacle avoidance operation, an object damage avoidance operation, etc., which cannot be dealt with by conventional position control, and obtain a robot 100 capable of safe and detailed work. Can do. Furthermore, the robot 100 can stably detect a highly accurate force even with a small amount of displacement. Further, the present invention is not limited to this embodiment, and can be applied to a double-arm robot.

10, 10A, 10B, 10C ......... sensor module, 11 ......... sensor device, 12 ......... first member, 14 ......... base member, 15 ......... concave, 16 ......... ground electrode, 18A, 18B, 18C, 18D ......... Connection electrode, 20A, 20B, 20C, 20D ......... Side electrode, 21A, 21B, 21C, 21D ......... External electrode, 22A, 22B, 22C, 22D ......... Penetration electrode , 24... Side wall member, 26... Metallized, 28... Penetration electrode, 30 ... Opening, 32 ... End face (outer peripheral surface), 34, 34 A ... Second member, 36 ... …… Force transmitting portion 38 …… Peripheral portion 40 …… Flexible portion 42 …… Sensor element 44 …… Pressure receiving surface 46 …… First sensor element 48 A, 48 B ………… First crystal plate, 50... First detection electrode, 52. ... second sensor element, 54A, 54B ......... second crystal plate, 56 ......... second detection electrode, 58 ......... third sensor element, 60A, 60B ......... third crystal plate, 62 ......... Third detection electrode, 64... First ground electrode, 66... Second ground electrode, 68 A, 68 B, 68 C, 68 D, 68 E ... Wire, 70 ... First plate, 72 ... 1 pressing portion, 73 ... pressing surface, 74 through hole, 80, 80A ... second plate, 82 ... screw hole, 84 second pressing portion, 86 fastening portion , 90... Force detecting device, 96... Mounting electrode, 100... Robot, 102... Main body, 104 ... Arm portion, 106 First frame, 108 Second Frame 110 ......... Third frame 112 ......... Fourth frame 114 ......... Fifth frame 116 ......... Robot hand section, 118 ......... Robot hand connection section, 120 ......... Robot hand, 200 ......... Sensor device, 202 ......... Package, 204 ......... Lid, 206 ......... Coaxial Connector, 208 ......... Outer peripheral portion, 210 ......... Center conductor, 212 ......... Insulating resin, 214 ......... Sensor element, 216 ......... Quartz plate, 218 ...... Electrode plate, 220 ......... Opening Part, 222... Upper surface, 224... Upper surface, 226.

Claims (9)

A sensor element having a piezoelectric body;
A first member on which the sensor element is disposed;
A second member that joins the first member and seals the first member;
A first plate and a second plate for supporting the first member and the second member between the plates;
A fastening portion for fixing the first member between the first plate and the second plate;
With
The first plate is formed with a first pressing portion projecting toward the second member on the surface on the first member side,
The sensor module, wherein the second member is sandwiched between the first pressing portion and a pressure receiving surface of the sensor element.   The first pressing portion has a surface that overlaps with the entire area of the pressure receiving surface of the sensor element in a plan view, and is positioned inside an inner peripheral region of the first member in a plan view. The sensor module according to claim 1, wherein the first member between the first plate and the second plate is fixed while being pressed.   3. The sensor module according to claim 1, wherein the second plate is formed on a surface on the first member side such that a second pressing portion faces the first pressing portion. 4.   The sensor module according to claim 3, wherein a recess that fits with the second pressing portion is formed on the mounting surface of the first member.   The said 2nd member formed the cyclic | annular flexible part inside the area | region of the inner peripheral edge of the said 1st member by the outer side from the pressure receiving surface of a sensor element by planar view, and planar view. The sensor module according to any one of 1 to 4.   When the stacking direction of the sensor elements in which a plurality of the piezoelectric bodies are stacked is the Z-axis direction, when the directions orthogonal to the Z-axis direction and orthogonal to each other are the X-axis direction and the Y-axis direction, respectively, at least the X A first sensor element for detecting an axial force, a second sensor element for detecting the Y-axis direction force, and a third sensor element for detecting the Z-axis direction force. The sensor module according to claim 1.   A force detection device comprising the sensor module according to claim 1.   A robot comprising the force detection device according to claim 7. The main body,
An arm connected to the main body,
A hand unit connected to the arm unit,
A sensor module is provided at a connection portion between the arm portion and the hand portion,
The sensor module is
A sensor element having a piezoelectric body;
A first member on which the sensor element is disposed;
A second member that is bonded to an end face of the side wall of the first member and seals the first member;
A first plate and a second plate for supporting the first member and the second member between the plates;
A fastening portion for fixing the first member between the first plate and the second plate;
With
The first plate is formed with a first pressing portion projecting toward the second member on the surface on the first member side,
The robot, wherein the second member is sandwiched between the first pressing portion and a pressure receiving surface of the sensor element.