Inertial measurement unit and method for manufacturing inertial measurement unit

Abstract

To provide an inertial measurement unit and a method for manufacturing an inertial measurement unit that can prevent a deterioration in detection characteristics.SOLUTION: An inertial measurement device has: a sensor substrate that has a substrate having a first surface and a first side face, and a first inertial sensor arranged on the first side face; a case that accommodates the sensor substrate; a first partition part that is arranged inside the case, and forms a first space surrounding the first inertial sensor inside the case; and a first filling member that is filled into the first space and covers the first inertial sensor.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an inertial measurement unit and a method for manufacturing an inertial measurement unit. [Background technology]

[0002] The inertial measurement device described in Patent Document 1 has an inner case, a board mounted on the underside of the inner case, a Z-axis angular velocity sensor and an acceleration sensor mounted on the top surface of the board, an X-axis angular velocity sensor and a Y-axis angular velocity sensor mounted on the side of the board, and an outer case that covers the inner case and houses the board between the inner case and the outer case.

[0003] A recess is formed on the bottom surface of the inner case, and the X-axis, Y-axis, and Z-axis angular velocity sensors and acceleration sensors are disposed at positions overlapping with the recess. The recess is filled with a filling material, which seals the entire Z-axis angular velocity sensor and acceleration sensor, and seals the upper halves of the X-axis and Y-axis angular velocity sensors.

[0004] In the inertial measurement device of Patent Document 1, the filler member is disposed to reduce the influence of external noise vibrations and improve the stability of detection accuracy. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-20829 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the inertial measurement device of Patent Document 1, only the upper halves of the X-axis angular velocity sensor and the Y-axis angular velocity sensor are sealed with a sealing member, which causes an uneven balance of stress applied to the X-axis angular velocity sensor and the Y-axis angular velocity sensor, resulting in a problem of deterioration of detection characteristics. [Means for solving the problem]

[0007] The inertial measurement device of the present invention includes a sensor substrate having a substrate having a first surface and a first side surface, and a first inertial sensor disposed on the first side surface; a case for accommodating the sensor substrate; a first partition portion disposed within the case and defining a first space within the case surrounding the first inertial sensor; A first filling member is filled in the first space and covers the first inertial sensor.

[0008] The method for manufacturing an inertial measurement device of the present invention includes a first filling step of filling a recess provided in a first case with a bottom filling member; a sensor substrate placement step of placing a sensor substrate in the recess, the sensor substrate having a substrate having a first surface and a first side surface and a first inertial sensor disposed on the first side surface; a first partitioning portion disposing step of disposing a first partitioning portion in the recessed portion to form a first space surrounding the first inertial sensor in the first case; a second filling step of filling the first space with an opening side filling member to cover the first inertial sensor; a filling member hardening step of hardening the bottom filling member and the opening filling member to form a first filling member that covers the first inertial sensor; and a case mounting step of mounting a second case to the first case so as to close the recess. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a top view showing an inertial measurement unit according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the inertial measurement unit; [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 4] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Diagram 5] FIG. [Figure 6] FIG. 2 is a plan view showing an angular velocity sensor. [Figure 7] 5A and 5B are schematic diagrams illustrating a driving state of the angular velocity sensor. [Figure 8] 5A and 5B are schematic diagrams illustrating a driving state of the angular velocity sensor. [Figure 9] 4 is a flowchart illustrating a method for manufacturing an inertial measurement unit. [Figure 10] 5A to 5C are cross-sectional views for explaining a manufacturing method of the inertial measurement device. [Figure 11] 5A to 5C are cross-sectional views for explaining a manufacturing method of the inertial measurement device. [Figure 12] 5A to 5C are cross-sectional views for explaining a manufacturing method of the inertial measurement device. [Figure 13] 5A to 5C are cross-sectional views for explaining a manufacturing method of the inertial measurement device. [Figure 14] 5A to 5C are cross-sectional views for explaining a manufacturing method of the inertial measurement device. [Figure 15] 5A to 5C are cross-sectional views for explaining a manufacturing method of the inertial measurement device. [Figure 16] 5A to 5C are cross-sectional views for explaining a manufacturing method of the inertial measurement device. [Figure 17] FIG. 11 is a top view showing an inertial measurement unit according to a second embodiment. [Figure 18] FIG. 2 is an exploded perspective view of the inertial measurement unit; [Figure 19] 18 is a cross-sectional view taken along line CC in FIG. 17. [Figure 20] 18 is a cross-sectional view taken along line DD in FIG. 17. [Figure 21] FIG. 11 is an exploded perspective view of an inertial measurement unit according to a third embodiment. [Figure 22] FIG. 2 is a cross-sectional view of an inertial measurement unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The inertial measurement unit and the method of manufacturing the inertial measurement unit of the present invention will be described in detail below based on the embodiments shown in the accompanying drawings. For convenience of explanation, three mutually orthogonal axes are illustrated as the X-axis, the Y-axis, and the Z-axis in Figs. 1 to 5 and 10 to 16. For convenience of explanation, the direction parallel to the X-axis will also be referred to as the "X-axis direction", the direction parallel to the Y-axis will also be referred to as the "Y-axis direction", and the direction parallel to the Z-axis will also be referred to as the "Z-axis direction". The arrow side of the Z-axis direction will also be referred to as the "upper" and the opposite side as the "lower".

[0011] First Embodiment FIG. 1 is a top view showing an inertial measurement unit according to a first embodiment. FIG. 2 is an exploded perspective view of the inertial measurement unit. FIG. 3 is a cross-sectional view taken along line AA in FIG. 1. FIG. 4 is a cross-sectional view taken along line BB in FIG. 1. FIG. 5 is a top view of an inner case. FIG. 6 is a plan view showing an angular velocity sensor. FIGS. 7 and 8 are schematic views showing the driving state of the angular velocity sensor. FIG. 9 is a flowchart showing a method for manufacturing an inertial measurement unit. FIGS. 10 to 16 are cross-sectional views for explaining a method for manufacturing an inertial measurement unit.

[0012] 1 is an inertial measurement unit (IMU) that detects the posture and behavior of an object to which it is attached, such as an automobile or a robot. The object to which it is attached is not limited to moving bodies such as an automobile or a robot, but may be, for example, a structure such as a bridge, an elevated road, or a track. When the inertial measurement unit 1 is attached to a structure, it is used as a structural health monitoring system that checks the soundness of the structure.

[0013] 1 and 2, the inertial measurement device 1 has a case 2, a sensor board 50 housed in the case 2, and a first partition section 9 housed in the case 2 and disposed on the sensor board 50. The sensor board 50 also has a board 5, and an X-axis angular velocity sensor 7X as a first inertial sensor, a Y-axis angular velocity sensor 7Y as a second inertial sensor, a Z-axis angular velocity sensor 7Z as a third inertial sensor, and a circuit element 8 as an electronic component, all of which are mounted on the board 5. Each of these sections will be described in order below.

[0014] <Case 2> As shown in Figs. 1 and 2, the case 2 has an inner case 3 as a first case and an outer case 4 as a second case that covers the inner case 3. The inner case 3 and the outer case 4 are each made of aluminum. This provides the case 2 with sufficiently high rigidity. In particular, in this embodiment, the surfaces of the inner case 3 and the outer case 4 are each anodized to provide insulation to the case 2. However, the materials of which the inner case 3 and the outer case 4 are made are not particularly limited, and may be made of metal materials such as titanium, magnesium, and stainless steel, or ceramics such as alumina and titania.

[0015] The inner case 3 is a box-like shape that opens upward and has a rectangular parallelepiped shape with two diagonal corners chamfered flatly. Furthermore, screw holes 31 for fixing the outer case 4 are formed in the other two diagonal corners of the inner case 3.

[0016] 3 to 5, the inner case 3 has a recess 32 that opens to the top surface 3a. The recess 32 has a first recess 321 that opens to the top surface 3a and a second recess 322 that opens to the bottom surface of the first recess 321 and has a smaller opening than the first recess 321. The inner case 3 has a through hole 33 that penetrates the bottom surface 3b and the bottom surface of the first recess 321. The through hole 33 is a hole for exposing a connector 51, which will be described later, to the outside.

[0017] Moreover, the inner case 3 has a second partition portion 34 and a third partition portion 35 disposed on the bottom surface of the second recess 322. The second and third partition portions 34, 35 are protrusions protruding upward from the bottom surface of the second recess 322, and are formed integrally with the inner case 3. This makes it easy to form the second partition portion 34 and the third partition portion 35. Also, the mechanical strength of the second partition portion 34 and the third partition portion 35 is sufficiently high. However, this is not limited thereto, and the second partition portion 34 and the third partition portion 35 may be formed separately from the inner case 3.

[0018] As shown in FIG. 3, the second partition 34 faces an inner peripheral surface 322a located on the negative side of the second recess 322 in the X-axis direction at a distance, and extends straight along the Y-axis direction. Also, as shown in FIG. 5, both ends of the second partition 34 are spaced apart from the inner peripheral surface of the second recess 322, and a gap G1 is formed between them. On the other hand, as shown in FIG. 4, the third partition 35 faces an inner peripheral surface 322b located on the positive side of the second recess 322 in the Y-axis direction at a distance, and extends straight along the X-axis direction. Also, as shown in FIG. 5, both ends of the third partition 35 are spaced apart from the inner peripheral surface of the second recess 322, and a gap G2 is formed between them.

[0019] 3 and 4, the upper surfaces of the second partitioning portion 34 and the third partitioning portion 35 are flush with the bottom surface of the first recessed portion 321. The upper surfaces of the second partitioning portion 34 and the third partitioning portion 35, together with the bottom surface of the first recessed portion 321, function as a mounting surface F on which the substrate 5 is placed.

[0020] As shown in FIG. 2, the outer case 4 is a box-like shape that opens downward, and has a rectangular parallelepiped shape. The outer case 4 covers the inner case 3 from above by inserting the inner case 3 into a recess 43 that opens on the lower surface. The shape of the opening of the outer case 4 is aligned with the outer shape of the inner case 3. This suppresses the outer case 4 from rattling relative to the inner case 3. Furthermore, screw holes 41 that overlap with the screw holes 31 are formed in two corners located on one diagonal line of the outer case 4. The inner case 3 and the outer case 4 are fixed by mounting screws B1 inserted into the screw holes 31 and 41. However, the method of fixing the outer case 4 to the inner case 3 is not particularly limited. Furthermore, screw holes 42 are formed in two corners located on the other diagonal line of the outer case 4. The inertial measurement device 1 is attached to the attachment body by mounting screws B2 inserted into these two screw holes 42. However, the method of attaching to the attachment body is not particularly limited.

[0021] <Substrate 5> The substrate 5 is a circuit board, and is, for example, a multi-layer glass epoxy substrate. However, the configuration of the substrate 5 is not particularly limited, and may be, for example, a multi-layer ceramic substrate. As shown in FIG. 2, the substrate 5 has an upper surface 5a as a first surface and a lower surface 5b as a second surface, which are in a front-back relationship. The substrate 5 also has a side surface connecting the upper surface 5a and the lower surface 5b, and the side surface includes a first side surface 5c facing the negative side in the X-axis direction and a second side surface 5d facing the positive side in the Y-axis direction. The substrate 5 having such a configuration is accommodated in the recess 32 of the inner case 3. As shown in FIG. 3 and FIG. 4, the substrate 5 is placed on the placement surface F of the inner case 3 with the upper surface 5a facing upward.

[0022] 3, a connector 51 is provided on the lower surface 5b of the substrate 5. The connector 51 is a plug-type connector, and is exposed to the outside of the inertial measurement unit 1 through a through hole 33 formed in the inner case 3. This facilitates electrical connection between the inertial measurement unit 1 and an external device. Furthermore, an X-axis angular velocity sensor 7X, a Y-axis angular velocity sensor 7Y, a Z-axis angular velocity sensor 7Z, and a circuit element 8 are mounted on the substrate 5.

[0023] <X-axis, Y-axis, Z-axis angular velocity sensors 7X, 7Y, 7Z> 3, the X-axis angular velocity sensor 7X is mounted on the first side surface 5c of the substrate 5, facing the negative side in the X-axis direction. The X-axis angular velocity sensor 7X is longer in the Z-axis direction than the substrate 5, and is provided protruding from both the top and bottom of the substrate 5. The bottom end of the X-axis angular velocity sensor 7X (the portion below the substrate 5) is inserted between the second partition 34 and the inner circumferential surface 322a. Such an X-axis angular velocity sensor 7X detects an angular velocity ωx about the X-axis.

[0024] 4, the Y-axis angular velocity sensor 7Y is mounted on the second side surface 5d of the substrate 5, facing the positive side in the Y-axis direction. The Y-axis angular velocity sensor 7Y is longer in the Z-axis direction than the substrate 5, and is provided protruding from both the top and bottom of the substrate 5. The bottom end of the Y-axis angular velocity sensor 7Y (the portion below the substrate 5) is inserted between the third partition portion 35 and the inner circumferential surface 322b. The Y-axis angular velocity sensor 7Y detects the angular velocity ωy around the Y-axis.

[0025] 3 and 4, the Z-axis angular velocity sensor 7Z is mounted facing downward on the lower surface 5b of the substrate 5. The Z-axis angular velocity sensor 7Z is inserted between the second partition 34 and the third partition 35. The Z-axis angular velocity sensor 7Z detects the angular velocity ωz about the Z axis.

[0026] The X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z are each packaged surface-mount components. This allows them to exhibit higher mechanical strength than components with exposed elements. Furthermore, it makes it easier to mount the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z on the substrate 5.

[0027] In addition, the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z have the same basic configuration except that the vibration frequencies of the sensor elements 74, which will be described later, are different in order to suppress interference between them, and they are arranged at right angles to each other so that their detection axes face the X-axis, Y-axis, and Z-axis.

[0028] 6, each of the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z has a package 71 and a sensor element 74 housed in the package 71. The package 71 also has a box-shaped base 72 having a recess 721 and supporting the sensor element 74 housed in the recess 721, and a lid 73 joined to the base 72 so as to close the opening of the recess 721. The base 72 also has a connection terminal (not shown) electrically connected to the sensor element 74, and is electrically connected to the substrate 5 via the connection terminal.

[0029] The sensor element 74 is, for example, a quartz crystal vibration element having a drive vibration arm and a detection vibration arm. In the illustrated configuration, the quartz crystal vibration element has a base 740 fixed to a base 72 via a support substrate 75, four drive vibration arms 742, and two detection vibration arms 741. In such a quartz crystal vibration element, when an angular velocity ω about a detection axis J is applied in a state in which a drive signal is applied to drive and vibrate the drive vibration arm 742 as shown in FIG. 7, a detection vibration is excited in the detection vibration arm 741 by the Coriolis force as shown in FIG. 8. Then, the charge generated in the detection vibration arm 741 by the detection vibration is extracted as a detection signal, and the angular velocity ω can be obtained based on the extracted detection signal.

[0030] The configurations of the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z have been described above. The X-axis angular velocity sensor 7X is disposed so that its detection axis J is along the X-axis, the Y-axis angular velocity sensor 7Y is disposed so that its detection axis J is along the Y-axis, and the Z-axis angular velocity sensor 7Z is disposed so that its detection axis J is along the Z-axis.

[0031] However, the configurations of the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z are not particularly limited. For example, they may be configured to use silicon MEMS vibration elements as the sensor elements.

[0032] <Circuit element 8> 3 and 4, the circuit element 8 is mounted on the upper surface 5a of the substrate 5. The circuit element 8 is electrically connected to the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z via the substrate 5. Such a circuit element 8 is, for example, an MCU (Micro Controller Unit), and controls each part of the inertial measurement device 1. Specifically, the circuit element 8 has a control circuit that controls the driving of the X-axis, Y-axis, and Z-axis angular velocity sensors 7X, 7Y, and 7Z, and an interface circuit that communicates with the outside.

[0033] The control circuit independently controls the driving of the X-axis, Y-axis, and Z-axis angular velocity sensors 7X, 7Y, and 7Z, and independently detects the angular velocity around each of the X-axis, Y-axis, and Z-axis based on the detection signals output from the X-axis, Y-axis, and Z-axis angular velocity sensors 7X, 7Y, and 7Z. The interface circuit transmits and receives signals, receives commands from an external device, and outputs detected angular velocity and acceleration to an external device. The communication method of the interface circuit is not particularly limited, but in this embodiment, it is SPI (Serial Peripheral Interface) communication. SPI communication is a communication method suitable for connecting multiple sensors. Since all signals related to angular velocity and acceleration can be output from one pin, it is possible to reduce the number of pins of the inertial measurement unit 1.

[0034] In addition, in addition to the X-axis angular velocity sensor 7X, Y-axis angular velocity sensor 7Y, Z-axis angular velocity sensor 7Z and circuit element 8 described above, several other electronic components are mounted on the substrate 5; however, for the sake of convenience, these will not be shown or described.

[0035] <First partition 9> As shown in FIG. 3 and FIG. 4, the first partitioning portion 9 is accommodated in the recess 32 of the inner case 3 together with the substrate 5. The first partitioning portion 9 is located above the substrate 5 and placed on the upper surface 5a. The upper surface of the first partitioning portion 9 is in contact with the bottom surface of the recess 43 of the outer case 4. Therefore, the substrate 5 and the first partitioning portion 9 are sandwiched between the inner case 3 and the outer case 4, and rattling of these within the case 2 can be suppressed. The outer shape of the first partitioning portion 9 is aligned with the shape of the recess 32 of the inner case 3. This suppresses rattling of the first partitioning portion 9 relative to the inner case 3.

[0036] Such a first partitioning portion 9 is made of aluminum. This provides the case 2 with sufficiently high rigidity. In particular, in this embodiment, the surface is anodized to provide insulation. Furthermore, by making the first partitioning portion 9 from the same material as the inner case 3 and the outer case 4, it is possible to make their thermal expansion coefficients equal. However, the materials constituting the inner case 3 and the outer case 4 are not particularly limited, and may be made of metal materials such as titanium, magnesium, and stainless steel, or ceramics such as alumina and titania.

[0037] As shown in FIG. 1, the first partitioning portion 9 has a frame shape in plan view from the Z-axis direction. That is, the first partitioning portion 9 has a through hole 91 penetrating the upper and lower surfaces. The circuit element 8 is disposed in the through hole 91. The first partitioning portion 9 has an outer side surface 9c facing the negative side in the X-axis direction, and a recess 92 is formed in the outer side surface 9c. The first partitioning portion 9 has an outer side surface 9d facing the positive side in the Y-axis direction, and a recess 93 is formed in the outer side surface 9d. The recesses 92 and 93 are cutout holes that open on the outer side surface of the first partitioning portion 9 and are formed to penetrate the upper and lower surfaces. The upper approximately half of the X-axis angular velocity sensor 7X is disposed in the recess 92, and the upper approximately half of the Y-axis angular velocity sensor 7Y is disposed in the recess 93.

[0038] 3 has a cross-sectional structure symmetrical with respect to the first partition 34 and the substrate 5. This makes it possible to uniform the stress that the first filling member MD1 around the X-axis angular velocity sensor 7X applies to the X-axis angular velocity sensor 7X. Similarly, the recess 93 in FIG. 4 has a cross-sectional structure symmetrical with respect to the second partition 35 and the substrate 5. This makes it possible to uniform the stress that the second filling member MD2 around the Y-axis angular velocity sensor 7Y applies to the Y-axis angular velocity sensor 7Y.

[0039] In the inertial measurement device 1 as described above, a first space Q1, a second space Q2, a third space Q3 and a fourth space Q4 are formed within the case 2 by the substrate 5, the first partition 9, the second partition 34 and the third partition 35.

[0040] 3, the first space Q1 is defined within the case 2 by the recess 92 of the first partition 9, the substrate 5, and the second partition 34, and by a wall W1 extending in a straight line from the bottom surface of the recess 32 to the opening. With this configuration, the first space Q1 can be easily formed. The X-axis angular velocity sensor 7X is disposed in the first space Q1.

[0041] 4, the second space Q2 is formed in the case 2 by the recess 93 of the first partition 9, the substrate 5, and the third partition 35, and by the wall W2 extending in a straight line from the bottom surface of the recess 32 to the opening. With this configuration, the second space Q2 can be easily formed. The Y-axis angular velocity sensor 7Y is disposed in the second space Q2.

[0042] As shown in FIG. 3 and FIG. 4, the third space Q3 is formed in the case 2 by the substrate 5 and the second and third partitions 34 and 35. With this configuration, the third space Q3 can be easily formed. The third space Q3 is located on the opposite side of the second partition 34 from the first space Q1 and on the opposite side of the third partition 35 from the second space Q2. In other words, the third space Q3 is arranged in the X-axis direction next to the first space Q1 across the second partition 34, and arranged in the Y-axis direction next to the second space Q2 across the third partition 35. The Z-axis angular velocity sensor 7Z is arranged in the third space Q3. As shown in FIG. 3 and FIG. 4, the fourth space Q4 is formed in the case 2 by the substrate 5 and the through hole 91 of the first partition 9. The circuit element 8 is arranged in the fourth space Q4.

[0043] The first space Q1, the second space Q2, and the third space Q3 are not completely independent, but communicate with each other through the gaps G1 and G2. By providing the gaps G1 and G2 in this way, as described later, when manufacturing the inertial measurement device 1, the uncured filling material MD flows across the first space Q1, the second space Q2, and the third space Q3, making it easy to fill the filling material MD and simplifying the manufacturing of the inertial measurement device 1. However, without being limited to this, the gaps G1 and G2 may be eliminated and the first space Q1, the second space Q2, and the third space Q3 may be independent from each other. In contrast, the fourth space Q4 is independent and is isolated from the first space Q1, the second space Q2, and the third space Q3. This makes it possible to effectively suppress the intrusion of the filling material MD into the fourth space Q4.

[0044] 3 and 4, the first space Q1, the second space Q2, and the third space Q3 are each filled with a filling member MD. Specifically, the first space Q1 is filled with a first filling member MD1, the second space Q2 is filled with a second filling member MD2, and the third space Q3 is filled with a third filling member MD3. In contrast, the fourth space Q4 is not filled with the filling member MD and is hollow.

[0045] The first filling member MD1 is filled so as to fill the inside of the first space Q1, and covers the entire X-axis angular velocity sensor 7X arranged in the first space Q1. Similarly, the second filling member MD2 is filled so as to fill the inside of the second space Q2, and covers the entire Y-axis angular velocity sensor 7Y arranged in the second space Q2. Moreover, the third filling member MD3 is filled so as to fill the inside of the third space Q3, and covers the entire Z-axis angular velocity sensor 7Z arranged in the third space Q3.

[0046] As the filling member MD, a material that is hard, has low hygroscopicity, and has a small thermal expansion coefficient is suitable. In this embodiment, a thermosetting epoxy adhesive is used as the filling member MD. This results in a filling member MD that has a high balance of the above-mentioned characteristics. The hardness of the filling member MD after curing is not particularly limited, but is preferably 80D or more, and more preferably 90D or more, in terms of a type D durometer in the JIS 7215-1986 durometer hardness test. Various fillers may be contained in the epoxy adhesive. This makes it possible to easily adjust the hardness and thermal expansion coefficient.

[0047] In this way, the X-axis angular velocity sensor 7X is housed in the first space Q1 formed by the wall W1 and the inner case, and the gap between the X-axis angular velocity sensor 7X and the first space Q1 is covered with the first filling member MD1, so that the amount of filling member around the X-axis angular velocity sensor 7X can be minimized. Therefore, moisture and humidity to the first filling member MD1 and the X-axis angular velocity sensor 7X can be effectively suppressed. In addition, for example, even if the first filling member MD1 absorbs moisture and expands, compared to a conventional configuration in which a part of the X-axis angular velocity sensor 7X is exposed from the filling member MD, the X-axis angular velocity sensor 7X is uniformly stressed from its periphery, so that fluctuations in detection characteristics can be suppressed. The same effect can be achieved by covering the entire Y-axis angular velocity sensor 7Y with the second filling member MD2 and the entire Z-axis angular velocity sensor 7Z with the third filling member MD3. Therefore, an inertial measurement unit 1 with excellent moisture resistance and good detection accuracy can be provided.

[0048] The inertial measurement unit 1 has been described above. Next, a manufacturing method of the inertial measurement unit 1 will be described. As shown in FIG. 9, the manufacturing method of the inertial measurement unit 1 includes a first filling step S1 of filling the recess 32 of the inner case 3 with a bottom side filling member MDa, a sensor substrate mounting step S2 of mounting the sensor substrate 50 in the recess 32, a first partition portion arranging step S3 of arranging the first partition portion 9 in the recess 32, a second filling step S4 of filling the recess 32 with an opening side filling member MDb, a filling member hardening step S5 of hardening the bottom side filling member MDa and the opening side filling member MDb, and a case mounting step S6 of mounting the outer case 4 to the inner case 3. Note that, in the following, the manufacturing method will be described using the AA line cross-sectional view in FIG. 1, so that some members will appear in the description but will not be shown.

[0049] ≪First filling process S1≫ In the first filling step S1, as shown in FIG. 10, the bottom filling material MDa is filled in the second recess 322 of the inner case 3. At this time, the bottom filling material MDa flows through the gaps G1 and G2 to wrap around the back sides of the second and third partitions 34 and 35, so that the bottom filling material MDa can be filled in the entire area of ​​the second recess 322 without excess or deficiency. Therefore, the occurrence of voids can be effectively suppressed. Although not shown, the bottom filling material MDa is also applied to the mounting surface F. The bottom filling material MDa applied to the mounting surface F functions as an adhesive for bonding the sensor substrate 50 to the mounting surface F.

[0050] <Sensor substrate placement process S2> In the sensor substrate mounting step S2, first, as shown in FIG. 11, a substrate 5 on which X-axis angular velocity sensor 7X, Y-axis angular velocity sensor 7Y, Z-axis angular velocity sensor 7Z and circuit elements 8 are mounted, that is, a sensor substrate 50 is prepared.

[0051] 12, the sensor substrate 50 is inserted into the recess 32 and placed on the placement surface F. This places the sensor substrate 50 in a state of being housed in the inner case 3. A third space Q3 is formed between the sensor substrate 50 and the inner case 3 by the second and third partitions 34, 35, and the entire Z-axis angular velocity sensor 7Z is embedded in the bottom filling member MDa that fills the third space Q3. The lower halves of the X-axis angular velocity sensor 7X and the Y-axis angular velocity sensor 7Y are embedded in the bottom filling member MDa.

[0052] <First partition arrangement process S3> 13, in the first partition portion arrangement process S3, the first partition portion 9 is inserted into the recess 32 and placed on the upper surface of the sensor substrate 50. This results in the first partition portion 9 being housed in the inner case 3. Furthermore, walls W1 and W2 are formed in the inner case 3, thereby forming a first space Q1, a second space Q2, and a fourth space Q4 in the inner case 3.

[0053] ≪Second filling process S4≫ In the second filling step S4, as shown in FIG. 14, the uncured opening side filling member MDb is filled into the first and second spaces Q1 and Q2 through the recesses 92 and 93. As a result, the upper halves of the X-axis angular velocity sensor 7X and the Y-axis angular velocity sensor 7Y are embedded in the opening side filling member MDb, and as a result, the entire X-axis angular velocity sensor 7X and the Y-axis angular velocity sensor 7Y are embedded in the filling member MD consisting of the bottom side filling member MDa and the opening side filling member MDb. This step S4 is performed before the bottom side filling member MDa filled in the first filling step S1 is cured. As a result, the bottom side filling member MDa and the opening side filling member MDb are integrated, and no boundary is generated between them when they are cured, and the stress applied to the periphery of the X-axis angular velocity sensor 7X and the Y-axis angular velocity sensor 7Y can be made uniform.

[0054] <Filling material hardening process S5> In the filling member hardening process S5, the filling member MD is hardened by heating as shown in Fig. 15. This forms a first filling member MD1 that covers the entire X-axis angular velocity sensor 7X, a second filling member MD2 that covers the entire Y-axis angular velocity sensor 7Y, and a third filling member MD3 that covers the entire Z-axis angular velocity sensor 7Z. Note that the method for hardening the filling member MD is not particularly limited.

[0055] <Case installation process S6 and> In the case mounting process S6, the outer case 4 is placed over the inner case 3, as shown in Fig. 16. Then, mounting screws B1 are inserted through the screw holes 31, 41 to fix the inner case 3 and the outer case 4 together.

[0056] This provides the inertial measurement unit 1. According to such a manufacturing method for the inertial measurement unit 1, it is possible to manufacture the inertial measurement unit 1 in which the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z are entirely sealed with the filling material MD through simple steps.

[0057] The manufacturing method of the inertial measurement device 1 is not particularly limited, and for example, the order of the filling member hardening step S5 and the case mounting step S6 may be reversed. In other words, the filling member MD may be hardened after the outer case 4 is mounted. According to such a method, the filling member MD can be hardened in a state in which the substrate 5 and the first partition portion 9 are sandwiched between the outer case 4 and the inner case 3, so that it is possible to effectively prevent the substrate 5 and the first partition portion 9 from shifting due to stress generated during hardening.

[0058] The inertial measurement device 1 and the manufacturing method of the inertial measurement device 1 of the present embodiment have been described above. As described above, the inertial measurement device 1 includes the substrate 5 having the upper surface 5a and the first side surface 5c as the first surface, the sensor substrate 50 having the X-axis angular velocity sensor 7X as the first inertial sensor arranged on the first side surface 5c, the case 2 that accommodates the sensor substrate 50, the first partitioning portion 9 arranged in the case 2 and forming the first space Q1 surrounding the X-axis angular velocity sensor 7X in the case 2, and the first filling member MD1 that fills the first space Q1 and covers the X-axis angular velocity sensor 7X. With this configuration, the amount of filling member around the X-axis angular velocity sensor 7X can be minimized, and moisture and humidity can be effectively suppressed from entering the first filling member MD1 and the X-axis angular velocity sensor 7X. Furthermore, for example, even if the first filling member MD1 absorbs moisture and expands, stress is applied uniformly to the X-axis angular velocity sensor 7X from all around it, compared to a conventional configuration in which a portion of the X-axis angular velocity sensor 7X is exposed from the first filling member MD1, so fluctuations in the detection characteristics can be suppressed.

[0059] As described above, the substrate 5 has the bottom surface 5b as a second surface that is opposite the top surface 5a. The inertial measurement device 1 also has a second partition 34 disposed between the bottom surface 5b and the case 2. The first space Q1 is formed by the first partition 9, the substrate 5, and the second partition 34. With this configuration, the first space Q1 can be easily formed.

[0060] As described above, the second partition portion 34 is a protrusion that protrudes from the inner surface of the case 2 toward the substrate 5. In other words, the second partition portion 34 is formed integrally with the case 2. This makes it easy to form the second partition portion 34. In addition, the mechanical strength of the second partition portion 34 can be increased.

[0061] As described above, the substrate 5 has a second side surface 5d different from the first side surface 5c. The sensor substrate 50 has a Y-axis angular velocity sensor 7Y as a second inertial sensor arranged on the second side surface 5d. The first partition 9 forms a second space Q2 surrounding the Y-axis angular velocity sensor 7Y. The inertial measurement device 1 has a second filling member MD2 that fills the second space Q2 and covers the Y-axis angular velocity sensor 7Y. With this configuration, the amount of filling member around the Y-axis angular velocity sensor 7Y can be minimized, and moisture and humidity can be effectively suppressed to the second filling member MD2 and the Y-axis angular velocity sensor 7Y. Even if the second filling member MD2 absorbs moisture and expands, for example, stress is applied uniformly to the Y-axis angular velocity sensor 7Y from its periphery, compared to a conventional configuration in which a part of the Y-axis angular velocity sensor 7Y is exposed from the second filling member MD2, so that fluctuations in detection characteristics can be suppressed.

[0062] As described above, the inertial measurement device 1 has the third partition 35 disposed between the lower surface 5b and the case 2. The second space Q2 is formed by the first partition 9, the substrate 5, and the third partition 35. With this configuration, the second space Q2 can be easily formed.

[0063] As described above, the third partition portion 35 is a protrusion that protrudes from the inner surface of the case 2 toward the substrate 5. That is, the third partition portion 35 is formed integrally with the case 2. This makes it easy to form the third partition portion 35. In addition, the mechanical strength of the third partition portion 35 can be increased.

[0064] As described above, the sensor substrate 50 has the Z-axis angular velocity sensor 7Z as the third inertial sensor arranged on the lower surface 5b. The substrate 5, the second partition 34, and the third partition 35 form a third space Q3 surrounding the Z-axis angular velocity sensor 7Z in the case 2. The inertial measurement device 1 has a third filling member MD3 that fills the third space Q3 and covers the Z-axis angular velocity sensor 7Z. With this configuration, the amount of filling member around the Z-axis angular velocity sensor 7Z can be minimized, and moisture and humidity can be effectively suppressed to the third filling member MD3 and the Z-axis angular velocity sensor 7Z. Even if the third filling member MD3 absorbs moisture and expands, for example, stress is applied uniformly to the Z-axis angular velocity sensor 7Z from its periphery, so that fluctuations in the detection characteristics can be suppressed.

[0065] As described above, the first space Q1, the second space Q2, and the third space Q3 are mutually connected. With this configuration, during the manufacture of the inertial measurement device 1, the uncured filling material MD can flow across the spaces Q1, Q2, and Q3, and the filling material MD can be uniformly filled into the spaces Q1, Q2, and Q3. This is expected to have the effect of suppressing the generation of voids in the spaces Q1, Q2, and Q3.

[0066] As described above, the sensor substrate 50 has the circuit element 8 as an electronic component disposed on the upper surface 5a. The first partition portion 9 forms a fourth space Q4 in the case 2, which is isolated from the first space Q1 and surrounds the circuit element 8. This makes it possible to effectively prevent the filler member MD from entering the fourth space Q4.

[0067] As described above, the manufacturing method of the inertial measurement device 1 includes a first filling step S1 of filling the recess 32 of the inner case 3 as the first case with the bottom filling member MDa, a sensor substrate mounting step S2 of mounting the sensor substrate 50 in the recess 32, the sensor substrate 5 having the substrate 5 having the upper surface 5a and the first side surface 5c as the first surface, and the X-axis angular velocity sensor 7X as the first inertial sensor disposed on the first side surface 5c, and a first partition portion 9 in the recess 32. The manufacturing method includes a first partition arrangement step S3 for forming a first space Q1 surrounding the X-axis angular velocity sensor 7X, a second filling step S4 for filling the first space Q1 with an opening-side filling member MDb to cover the X-axis angular velocity sensor 7X, a filling member hardening step S5 for hardening the bottom-side filling member MDa and the opening-side filling member MDb to form a first filling member MD1 that covers the X-axis angular velocity sensor 7X, and a case mounting step S6 for mounting an outer case 4 as a second case to the inner case 3 so as to close the recess 32. According to this manufacturing method, it is possible to easily form an inertial measurement unit 1 in which the periphery of the X-axis angular velocity sensor 7X is covered with a space Q1 with a minimum volume and the gap is covered with the first filling member MD1. Therefore, it is possible to effectively prevent moisture and humidity from entering the first filling member MD1 around the X-axis angular velocity sensor 7X and the X-axis angular velocity sensor 7X. Furthermore, for example, even if the first filling member MD1 absorbs moisture and expands, stress is applied uniformly to the X-axis angular velocity sensor 7X from all around it, compared to a conventional configuration in which a portion of the X-axis angular velocity sensor 7X is exposed from the first filling member MD1, so fluctuations in the detection characteristics can be suppressed.

[0068] As described above, the sensor substrate 50 has the Y-axis angular velocity sensor 7Y as the second inertial sensor arranged on the second side 5d different from the first side 5c of the substrate 5. In the first partition arrangement step S3, the first partition 9 is arranged to form a second space Q2 surrounding the Y-axis angular velocity sensor 7Y in the inner case 3, and in the second filling step S4, the opening side filling member MDb is filled in the second space Q2 to cover the Y-axis angular velocity sensor 7Y, and in the filling member hardening step S5, the bottom side filling member MDa and the opening side filling member MDb are hardened to form the second filling member MD2 covering the Y-axis angular velocity sensor 7Y. According to this manufacturing method, the inertial measurement device 1 can be easily formed in which the periphery of the Y-axis angular velocity sensor 7Y is covered with the space Q2 having the smallest possible volume, and the gap is covered with the second filling member MD2. Therefore, it is possible to effectively suppress the intrusion of moisture and humidity into the second filling member MD2 around the X-axis angular velocity sensor 7Y and the Y-axis angular velocity sensor 7Y. Furthermore, for example, even if the second filling member MD2 absorbs moisture and expands, stress is applied uniformly to the Y-axis angular velocity sensor 7Y from all around it, compared to a conventional configuration in which a portion of the Y-axis angular velocity sensor 7Y is exposed from the second filling member MD2, so fluctuations in the detection characteristics can be suppressed.

[0069] <Second embodiment> Fig. 17 is a top view showing an inertial measurement unit according to a second embodiment. Fig. 18 is an exploded perspective view of the inertial measurement unit. Fig. 19 is a cross-sectional view taken along line CC in Fig. 17. Fig. 20 is a cross-sectional view taken along line DD in Fig. 17.

[0070] This embodiment is similar to the first embodiment described above, except that the inertial measurement device 1 further includes an acceleration sensor 6. In the following description, the present embodiment will be described focusing on the differences from the first embodiment described above, and a description of the similarities will be omitted. In each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the previously described embodiment.

[0071] <Accelerometer 6> 17 and 18, the sensor substrate 50 has an acceleration sensor 6 mounted on the upper surface 5a of the substrate 5 as a fourth inertial sensor. The acceleration sensor 6 is a three-axis acceleration sensor that can detect acceleration in the X-axis direction, the Y-axis direction, and the Z-axis direction independently. The acceleration sensor 6 has a package 61 and sensor elements 64, 65, and 66 housed in the package 61. The acceleration sensor 6 is electrically connected to the substrate 5 via a connection terminal (not shown) arranged on the package 61.

[0072] Moreover, the sensor element 64 is an element that detects acceleration in the X-axis direction, the sensor element 65 is an element that detects acceleration in the Y-axis direction, and the sensor element 66 is an element that detects acceleration in the Z-axis direction. These sensor elements 64, 65, and 66 are silicon MEMS vibration elements having a fixed electrode fixed to the package 61 and a movable electrode that is movable with respect to the package 61. In each of the sensor elements 64, 65, and 66, when acceleration is applied in the detection axis direction, the movable electrode is displaced relative to the fixed electrode, and accordingly, the capacitance formed between the fixed electrode and the movable electrode changes. Therefore, the change in the capacitance of the sensor elements 64, 65, and 66 can be extracted as a detection signal, and the acceleration in each axis direction can be obtained based on the extracted detection signal.

[0073] Although the acceleration sensor 6 has been described above, there is no particular limitation on the configuration of the acceleration sensor 6. For example, the acceleration sensor 6 may be configured to use a quartz crystal vibration element as the sensor element.

[0074] <First partition 9> As shown in FIG. 19 and FIG. 20, the first partition 9 has a recess 94 that opens to the bottom surface. The substrate 5 and the recess 94 form a fifth space Q5. The acceleration sensor 6 is disposed in the fifth space Q5. The fifth space Q5 is filled with a fourth filling member MD4, and the acceleration sensor 6 is surrounded by a space Q5 with a small volume as much as possible, and the gap is covered by the fourth filling member MD4. This configuration effectively prevents moisture and humidity from entering the fourth filling member MD4 around the acceleration sensor 6 and the acceleration sensor 6. Even if the fourth filling member MD4 absorbs moisture and expands, for example, stress is applied uniformly to the acceleration sensor 6 from its surroundings, and fluctuations in the detection characteristics can be suppressed.

[0075] As described above, in the inertial measurement device 1 of this embodiment, the sensor substrate 50 has the acceleration sensor 6 as the fourth inertial sensor arranged on the upper surface 5a. The first partition 9 forms a fifth space Q5 surrounding the acceleration sensor 6 inside the case 2. The inertial measurement device 1 has a fourth filling member MD4 that fills the fifth space Q5 and covers the acceleration sensor 6. With this configuration, the fourth filling member MD4 can effectively prevent moisture and humidity from entering the acceleration sensor 6. Even if the fourth filling member MD4 absorbs moisture and expands, for example, stress is applied uniformly to the acceleration sensor 6 from its periphery, so that fluctuations in the detection characteristics can be suppressed.

[0076] The second embodiment can achieve the same effect as the first embodiment. The acceleration sensor 6 is arranged on the upper surface 5a shown in Fig. 19 and Fig. 20, and is covered with the third filling member MD3 in the third space Q3. The acceleration sensor 6 can be arranged on the upper surface 5a and the lower surface 5c, and the output from the two acceleration sensors can be combined.

[0077] <Third embodiment> Fig. 21 is an exploded perspective view of the inertial measurement unit according to the third embodiment. Fig. 22 is a cross-sectional view of the inertial measurement unit. Fig. 22 corresponds to the cross-sectional view taken along line AA in Fig. 1.

[0078] This embodiment is similar to the first embodiment described above, except for the configuration of the first partition section 9. In the following description, the present embodiment will be described focusing on the differences from the first embodiment described above, and the description of the similarities will be omitted. In each drawing of this embodiment, the same reference numerals are used for the same configurations as those in the above-mentioned embodiment.

[0079] 21 and 22, the first partitioning portion 9 of this embodiment has a flange portion 99 protruding laterally from its upper end portion. The first partitioning portion 9 is positioned relative to the inner case 3 by placing this flange portion 99 on the upper surface 3a of the inner case 3. A screw hole 991 is formed in the flange portion 99 at a position overlapping with the screw hole 31 formed in the inner case 3. The first partitioning portion 9 and the outer case 4 are fastened together to the inner case 3 and fixed thereto.

[0080] The third embodiment as described above can also achieve the same effects as the first embodiment described above.

[0081] The inertial measurement unit and the manufacturing method for an inertial measurement unit of the present invention have been described above based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having a similar function. Any other configuration may be added to the present invention. Any purposed process may be added. Each embodiment may be combined as appropriate. [Explanation of symbols]

[0082] REFERENCE SIGNS LIST 1...inertial measurement unit, 2...case, 3...inner case, 3a...upper surface, 3b...lower surface, 31...screw hole, 32...recess, 321...first recess, 322...second recess, 322a...inner circumferential surface, 322b...inner circumferential surface, 33...through hole, 34...second partition, 35...third partition, 4...outer case, 41...screw hole, 42...screw hole, 43...recess, 5...substrate, 5a...upper surface, 5b...lower surface, 5c...first side, 5d...second side Surface, 50... sensor board, 51... connector, 6... acceleration sensor, 61... package, 64... sensor element, 65... sensor element, 66... ​​sensor element, 7X... X-axis angular velocity sensor, 7Y... Y-axis angular velocity sensor, 7Z... Z-axis angular velocity sensor, 71... package, 72... base, 721... recess, 73... lid, 74... sensor element, 740... base, 741... detection vibration arm, 742... drive vibration Arm, 75...supporting substrate, 8...circuit element, 9...first partition portion, 9c...outer surface, 9d...outer surface, 91...through hole, 92...recess, 93...recess, 94...recess, 99...flange portion, 991...screw hole, B1...mounting screw, B2...mounting screw, F...mounting surface, G1...gap, G2...gap, J...detection axis, MD...filling member, MD1...first filling member, MD2...second filling member, MD3...third filling member, MD4...fourth filling portion Material, MDa...bottom filling member, MDb...opening side filling member, Q1...first space, Q2...second space, Q3...third space, Q4...fourth space, Q5...fifth space, S1...first filling process, S2...sensor board mounting process S3...first partition placement process, S4...second filling process, S5...filling member hardening process, S6...case mounting process, W1...wall, W2...wall, ω...angular velocity, ωx...angular velocity, ωy...angular velocity, ωz...angular velocity

Claims

1. a sensor substrate having a substrate having a first surface and a first side surface, and a first inertial sensor disposed on the first side surface; a case for accommodating the sensor substrate; a first partition portion disposed within the case and defining a first space within the case surrounding the first inertial sensor; a first filling member that fills the first space and covers the first inertial sensor.

2. the substrate has a second surface opposite to the first surface; a second partition portion disposed between the second surface and the case; The inertial measurement unit according to claim 1 , wherein the first space is defined by the first partition, the substrate, and the second partition.

3. The inertial measurement unit according to claim 2 , wherein the second partition portion is a protrusion that protrudes from an inner surface of the case toward the board.

4. the substrate has a second side different from the first side; the sensor substrate has a second inertial sensor disposed on the second side; the first partition portion forms a second space surrounding the second inertial sensor, The inertial measurement device according to claim 2 , further comprising a second filling member that fills the second space and covers the second inertial sensor.

5. a third partition portion disposed between the second surface and the case; The inertial measurement unit according to claim 4 , wherein the second space is defined by the first partition, the substrate, and the third partition.

6. The inertial measurement unit according to claim 5 , wherein the third partition portion is a protrusion that protrudes from an inner surface of the case toward the board.

7. the sensor substrate has a third inertial sensor disposed on the second surface; the substrate, the second partition portion, and the third partition portion form a third space within the case surrounding the third inertial sensor; The inertial measurement device according to claim 5 , further comprising a third filling member that fills the third space and covers the third inertial sensor.

8. The inertial measurement device according to claim 7 , wherein the first space, the second space, and the third space communicate with each other.

9. the sensor substrate has an electronic component disposed on the first surface, 2 . The inertial measurement device according to claim 1 , wherein the first partition portion defines a fourth space within the case, the fourth space being isolated from the first space and surrounding the electronic component.

10. the sensor substrate has a fourth inertial sensor disposed on the first surface; the first partition portion forms a fifth space surrounding the fourth inertial sensor within the case, The inertial measurement device according to claim 1 , further comprising a fourth filling member filling the fifth space and covering the fourth inertial sensor.

11. a first filling step of filling a bottom filling member into a recess provided in the first case; a sensor substrate placement step of placing a sensor substrate in the recess, the sensor substrate including a substrate having a first surface and a first side surface and a first inertial sensor disposed on the first side surface; a first partitioning portion disposing step of disposing a first partitioning portion in the recessed portion to form a first space surrounding the first inertial sensor in the first case; a second filling step of filling the first space with an opening side filling member to cover the first inertial sensor; a filling member hardening step of hardening the bottom side filling member and the opening side filling member to form a first filling member covering the first inertial sensor; and a case mounting step of mounting a second case to the first case so as to cover the recess.

12. the sensor substrate has a second inertial sensor disposed on a second side of the substrate different from the first side, In the first partition portion disposing step, a second space surrounding the second inertial sensor is formed in the first case by disposing the first partition portion; In the second filling step, the opening side filling member is filled into the second space to cover the second inertial sensor, The method for manufacturing an inertial measurement device according to claim 11 , wherein in the filling member hardening step, the bottom side filling member and the opening side filling member are hardened to form a second filling member that covers the second inertial sensor.

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