JP4254016B2 - Angular velocity sensor and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an angular velocity sensor having an improved anti-vibration support structure for a detection element that detects angular velocity, and a method for manufacturing the same.
[0002]
[Problems to be solved by the invention]
2. Description of the Related Art In recent years, it has been considered that a vehicle (automobile) is equipped with a system for detecting a side slip by an angular velocity sensor (yaw rate sensor) and controlling the stabilization of the vehicle body. This type of angular velocity sensor has a configuration in which a detection element is provided in a housing so as to receive vibration in a detection frequency range, and a signal processing circuit board for processing a signal from the detection element is fixedly provided. However, when vehicle vibration noise or the like is applied to the detection element, a normal sensor output cannot be obtained, so that a vibration isolation support structure for the detection element is provided.
[0003]
As a conventional example of such an angular velocity sensor, there is a configuration shown in FIG. This is inserted into a beam-shaped rubber component 4 for vibration isolation with the detection element 2 supported on the substrate 3 at the lower part of the housing 1 and assembled. It is attached by the fixing member 5 at the part. The signal processing circuit board 6 is fixedly attached to the upper part of the housing 1 by screwing or the like, and is connected to the detection element 2 by a lead wire 7.
[0004]
Another conventional example has the configuration shown in FIG. In this structure, a substrate 11 supporting a detection element 10 is fitted into a cut-out portion 9a of a vibration-proof rubber component 9 having a damper shape, which is disposed in the lower part of the housing 8, and the rubber component. 9 is fixed to the housing 8 by a fixing member 12. The signal processing circuit board 13 is also fixedly attached to the upper portion of the housing 8 by screwing or the like, and is connected to the detection element 10 by a lead wire 14.
[0005]
However, in the conventional anti-vibration support structure for the detection elements 2 and 10, when the rubber parts 4 and 9 are assembled, both the insertion and insertion of the detection elements 2 and 10 into the rubber parts 4 and 9 and the rubber part 4 , 9 in the housings 1 and 8 are difficult to automate, and manual assembly is required, resulting in poor mass productivity.
[0006]
The present invention has been made in view of the above circumstances, and its purpose is to provide an anti-vibration support structure for the detection element, which eliminates manual assembly of rubber parts and the like to improve productivity. An object of the present invention is to provide an angular velocity sensor and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an angular velocity sensor according to the present invention has a detection element mounted on a flexible substrate, and the flexible substrate is suspended below the signal processing circuit substrate and is liquid in the housing. The detection element is buried in the anti-vibration rubber layer by filling and curing the rubber material (Invention of Claim 1).
[0008]
According to this, the detection element is suspended by the flexible substrate below the signal processing circuit substrate and can receive vibration in the detection frequency range, and is embedded in the anti-vibration rubber layer. Thus, it is supported in an anti-vibration state against ambient vibrations outside the detection frequency range. At this time, since the anti-vibration rubber layer is formed by filling and curing a liquid rubber material, unlike the case of assembling anti-vibration rubber parts made of molded products in the enclosure, the anti-vibration rubber layer is liquid in the enclosure. All that is required is to inject and cure the rubber material, which can be automated. As a result, productivity can be improved and quality can be stabilized.
[0009]
By the way, the following characteristics are required for the above-mentioned vibration-proof rubber layer. That is, first, since an angular velocity input in the detection frequency range (for example, 10 Hz or less for measuring the vehicle angular velocity) needs to be applied to the detection element, external vibration (angular velocity) is transmitted in that frequency range. thing. Second, if vibration near the resonance (drive) frequency (for example, several kHz) of the transducer of the detection element acts on the transducer, an error occurs in the output, so external vibration near the resonance (drive) frequency of the transducer is transmitted. Don't do it. Thirdly, since an error occurs in the output when a vibration having a difference frequency (for example, several hundred Hz to several kHz) between the resonance (drive) frequency of the vibrator and the detection frequency acts on the vibrator, an external vibration in the frequency range. Do not communicate. Fourthly, it can absorb an instantaneous shock G such as a drop and relax it below the tolerance of the vibrator.
[0010]
Such required properties of the vibration-proof rubber layer can be adjusted by the hardness of the vibration-proof rubber layer after curing and the filling amount (filling thickness) between the detection element and the casing. According to the inventor's study, in order to satisfy the required characteristics that describes above, a rubber cushion layer, it is made to provide a thickness of 5~10mm between the inner wall surface and the detection element housing Desirable (Invention of Claim 2 )
[0011]
In addition, as a material of the anti-vibration rubber layer (liquid rubber material), silicone rubber, butyl rubber, etc., as long as the rubber material is liquid at room temperature and is cured by a predetermined curing means such as a moisture curing type or a heat curing type. can be used various ones, a wide temperature range (e.g., -30 ° C. to 85 ° C.) the spring constant does not change by (not hard) and stable, it is most desirable to employ silicone rubber (claim 3 Invention).
[0012]
In the method of manufacturing the angular velocity sensor according to the present invention, the flexible substrate having the detection element mounted on the upper surface is connected in a suspended state below the signal processing circuit substrate, the signal processing circuit substrate is attached in the casing, A vibration-proof rubber layer is formed by filling and curing a rubber material in a casing so that the detection element is buried (invention of claim 4 ).
[0013]
According to this, the detection element is suspended by the flexible substrate below the signal processing circuit substrate and can receive vibration in the detection frequency range, and is embedded in the anti-vibration rubber layer. Thus, it is supported in an anti-vibration state against ambient vibrations outside the detection frequency range. At this time, since the anti-vibration rubber layer is formed by filling and curing a liquid rubber material, unlike the case where the anti-vibration rubber part made of a molded product is assembled in the case, a fixed amount of the anti-vibration rubber layer is provided in the case. All that is required is to inject and cure a liquid rubber material, which can be automated. As a result, productivity can be improved and quality can be stabilized.
[0014]
In this case, in filling (injecting) the liquid rubber material into the housing, if bubbles or voids are generated in the vibration-proof rubber layer, there is a risk of adversely affecting the vibration-proof characteristics, and no bubbles or voids are generated. Need to be filled. Thus, by filling the casing with a liquid rubber material by natural flow (invention of claim 5 ), it is possible to prevent air from being entrained in the anti-vibration rubber layer as much as possible. By making the lower surface side of the flexible substrate a smooth surface (the invention of claim 6 ), the liquid rubber material smoothly flows and fills the lower surface of the flexible substrate, which is caused by unevenness on the lower surface side of the flexible substrate. It is possible to prevent the occurrence of voids.
[0015]
Also, when filling (injecting) a liquid rubber material into the housing, if the detector element is tilted, it will be embedded in the anti-vibration rubber layer with the detector element tilted, resulting in an output error. And so on. Therefore, if the flexible substrate is symmetrically formed in the front-rear direction and the left-right direction, and the detection element is mounted at the center thereof (the invention of claim 7 ), the center of gravity of the flexible substrate matches the center of gravity of the detection element. Then, when the rubber material is filled, the detection element can be buried in the vibration-proof rubber layer without shifting from front to back and from side to side. Furthermore, if a weight member is attached to the center of the flexible substrate (invention of claim 8 ), it becomes possible to hold the detecting element in a more stable posture when filling with a rubber material, such as inclination. Occurrence can be prevented.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, with the one embodiment of applying the present invention for angular velocity detection in a vehicle (automobile) will be described with reference to FIGS. FIG. 1 schematically shows a main configuration of an angular velocity sensor (yaw rate sensor) 21 according to the present embodiment. This angular velocity sensor 21 has a configuration in which a detection element 23 is provided in a housing 22 via an anti-vibration support structure which will be described later, and a signal processing circuit board 24 for processing a signal from the detection element 23 is fixedly provided. Is done.
[0017]
The housing 22 is configured in a container shape with an open top surface, and is internally provided with mounting boss portions 25 located at four locations (only two are shown) and extending upward from the inner bottom surface. ing. The signal processing circuit board 24 is attached to the upper end portions of the mounting boss portions 25 at the four corners by screws 26 so that the signal processing circuit board 24 is attached to the upper portion in the housing 22 so as to be in a horizontal state. It has become. Although not shown, the upper surface opening of the housing 22 is closed by a lid (not shown), and a cable or the like for connecting the signal processing circuit board 24 and an external circuit is provided. Has been derived.
[0018]
Although not shown in detail, the detection element 23 includes, as is well known, a vibrator formed by combining driving (excitation) and detection piezoelectric ceramics in a rectangular outer shell, and has a Coriolis force. Based on the detection, the angular velocity is detected. At this time, the detection element 23 is arranged in a state of being mounted on a flexible substrate 27 having required flexibility (elasticity).
[0019]
As shown in FIG. 2, the flexible substrate 27 has connecting portions 27b and 27b extending in the left-right direction from the central portions of the left and right sides of the rectangular mounting portion 27a. It has a symmetrical shape. The detection element 23 is mounted at the center of the upper surface of the mounting portion 27a. In this embodiment, the lower surface side of the flexible substrate 27 is a smooth surface on which no components are mounted.
[0020]
As shown in FIG. 1, the flexible board 27 is arranged below the signal processing circuit board 24, and the connection portions 27 b and 27 b are arranged at the center of the left and right sides of the signal processing circuit board 24. To be connected to. Thus, the detection element 23 is provided in a suspended state below the signal processing circuit board 24. At this time, a wiring pattern (not shown) is formed on the upper surface of the flexible board 27, and the detection element 23 and the signal The processing circuit board 24 is electrically connected.
[0021]
An anti-vibration rubber layer 28 for anti-vibration support of the detection element 23 is provided in a filled state at a lower part in the housing 22 (slightly below the signal processing circuit board 24). It is like that. The detection element 23 (and the portion excluding the upper end portion of the flexible substrate 27) is buried in the anti-vibration rubber layer 28, so that disturbance vibration (detection frequency range (for example, 10 Hz or less)) is obtained. Anti-vibration from outside vibration) can be achieved.
[0022]
At this time, as will be described in the following description of the operation, the vibration-proof rubber layer 28 is a rubber material that is liquid at room temperature, for example, moisture curing, in the housing 22 in which the signal processing circuit board 24 and the detection element 23 are previously assembled. A mold or heat-curing type silicone rubber is quantitatively injected by natural flow using an automatic injection machine or the like and then cured. Also, vibration-proof rubber layer 28 is provided in a thickness of 5~10mm between the inner wall surface and the detection element 23 of the housing 22.
[0023]
Next, the operation of the above configuration will be described. The angular velocity sensor 21 having the above-described configuration is manufactured through the following steps. That is, first, a step of connecting the flexible substrate 27, on which the detection element 23 is previously mounted on the upper surface of the mounting portion 27a, in a suspended state below the signal processing circuit substrate 24 at the connection portions 27b, 27b is executed. The Next, a process of housing the signal processing circuit board 24 to which the flexible board 27 is connected in the housing 22 and attaching the signal processing circuit board 24 to the attachment boss portion 25 by screws is performed. Thus, the detection element 23 is provided in the housing 22 in a form elastically supported by the flexible substrate 27 below the signal processing circuit substrate 24.
[0024]
Thereafter, with respect to the case 22 in which the detection element 23, the signal processing circuit board 24, and the like are assembled as described above, a rubber material that is in a liquid state at room temperature is formed on the lower side of the case 22 and the detection element 23 (and the flexible substrate). A step of filling and curing so that the portion excluding the upper portion of 27 is buried is performed. As a result, the anti-vibration rubber layer 28 is formed in the housing 22.
[0025]
In this step, as described above, a fixed amount of rubber material made of moisture-curing type or heat-curing type silicone rubber is injected into the housing 22 by natural flow from above using an automatic injector. In this case, as described in the conventional example, the detection elements 2 and 10 are inserted and fitted into the rubber parts 4 and 9 for vibration isolation made of molded products, and the rubber parts 4 and 9 are inserted into the casings 1 and 8. Unlike the case where an operation that is difficult to automate, such as assembly, is required, the operation can be performed simply by injecting a liquid rubber material into the housing 22 and curing it.
[0026]
At this time, by using natural flow, air is prevented from being entrapped in the vibration-proof rubber layer 28 as much as possible, and the lower surface side of the flexible substrate 27 is a smooth surface, so that a liquid rubber material is used. As a result, the lower surface of the flexible substrate 27 smoothly flows and fills, and the occurrence of voids in the anti-vibration rubber layer 28 due to irregularities on the lower surface of the flexible substrate 27 is prevented. Further, since the detection element 23 is mounted at the center of the flexible substrate 27 that is symmetrical in the front-rear direction and the left-right direction, the center of gravity of the flexible substrate 27 coincides with the center of gravity of the detection element 23 and is filled with a rubber material. Sometimes, the detection element 23 can be buried in the anti-vibration rubber layer 28 without shifting from front to back and left and right.
[0027]
In the angular velocity sensor 21 manufactured as described above, the anti-vibration support structure by the anti-vibration rubber layer 28 with respect to the detection element 23 can satisfactorily prevent vibration from disturbance vibration such as vehicle vibration noise. Highly accurate sensor output can be obtained. In this case, in the present embodiment, the vibration-proof rubber layer 28, since the provided a thickness of 5~10mm between the inner wall surface and the detection element 23 of the housing 22, four being as follows requests It was possible to satisfy the characteristics.
[0028]
That is, first, since an angular velocity input (for example, 10 Hz or less) in the detection frequency range needs to be applied to the detection element 23, external vibration (angular velocity) is transmitted in the frequency range. Secondly, if vibration near the resonance (drive) frequency (for example, several kHz) of the vibrator of the detecting element 23 acts on the vibrator, an error occurs in the output. Do not communicate. Thirdly, since an error occurs in the output when a vibration having a difference frequency (for example, several hundred Hz to several kHz) between the resonance (drive) frequency of the vibrator and the detection frequency acts on the vibrator, an external vibration in the frequency range. Not communicate. The fourth characteristic is that an instantaneous shock G such as a drop is absorbed and can be relaxed below the tolerance of the vibrator.
[0029]
Furthermore, in this embodiment, as the material of the vibration damping rubber layer 28, since adopting a silicone rubber, not change the spring constant be in a wide temperature range (e.g., -30 ° C. to 85 ° C. which is environmental temperature of the vehicle) Therefore, it becomes stable (not hard) and suitable for use as the angular velocity sensor 21 for a vehicle.
[0030]
As described above, according to the angular velocity sensor 21 and the manufacturing method thereof of the present embodiment, the vibration isolating rubber layer 28 is formed by filling the casing 22 with a liquid rubber material and curing it. As a result, the formation of the anti-vibration rubber layer 28 can be automated, and the conventional manual assembly of the rubber parts 4 and 9 can be eliminated. As a result, the productivity is improved and the quality is stabilized. Can be achieved.
[0031]
In particular, according to the configuration of the anti-vibration rubber layer 28 of the present embodiment, it is possible to satisfy the required characteristics on the detection surface of the angular velocity and to be suitable for the environmental temperature of the vehicle. According to the manufacturing method of the present embodiment, when the liquid rubber material is filled (injected) into the housing 22, it is possible to effectively prevent bubbles and voids from being generated in the vibration-proof rubber 28 layer. It is possible to prevent the vibration-proof characteristic from being adversely affected by the air bubbles and the air gap, and to effectively prevent the detection element 23 that is buried in the vibration-proof rubber 28 layer from being inclined. Therefore, it is possible to obtain an advantage that an output error or the like caused by the inclination can be prevented.
[0032]
Figure 3 shows schematically a configuration of a main part of an angular velocity sensor 31 according to another embodiment of the present invention. This angular velocity sensor 31 differs from the angular velocity sensor 21 of the above embodiment in that a weight member 32 is attached to the lower surface of the mounting portion 27a, which is the central portion (center of gravity) of the flexible substrate 27. In this case, the weight member 32 is made of a synthetic resin plate-like member such as a printed circuit board having a size equivalent to that of the mounting portion 27a of the flexible substrate 27, and is attached to the lower surface side of the mounting portion 27a.
[0033]
According to this, in addition to substantially the same operation and effect as the above-described one embodiment, it is possible to hold the detection element 23 in a more stable posture when filling with a liquid rubber material, such as tilting. Can be more effectively prevented. The flexible substrate 27 can be reinforced. Of course, various materials and shapes can be used as the weight member.
[0034]
In addition, the present invention is not limited to each of the above-described embodiments. For example, the material of the anti-vibration rubber layer (liquid rubber material) is liquid at room temperature, and may be a predetermined type such as a moisture curable type or a heat curable type. As long as the rubber material is cured by this curing means, various materials such as butyl rubber can be adopted as well as silicone rubber. Further, the angular velocity sensor of the present invention can be implemented with appropriate modifications within a range that does not depart from the gist, such as being able to be used for various purposes other than for vehicles.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional front view schematically showing a configuration of an essential part of an angular velocity sensor according to an embodiment of the present invention. FIG. 2 is a plan view of a flexible substrate. FIG. 4 is a diagram corresponding to FIG. 1. FIG. 4 is a diagram corresponding to FIG. 1 illustrating a conventional example. FIG. 5 is a diagram corresponding to FIG.
In the drawing, 21 and 31 are angular velocity sensors, 22 is a housing, 23 is a detection element, 24 is a signal processing circuit board, 27 is a flexible substrate, 28 is a vibration-proof rubber layer, and 32 is a weight member.

Claims (8)

An angular velocity sensor in which a detection element is provided in a housing so as to receive vibration in a detection frequency range, and a signal processing circuit board for processing a signal from the detection element is fixedly provided.
A flexible board having the detection element mounted on the upper surface is connected to the signal processing circuit board in a suspended state below the signal processing circuit board, and
The angular velocity sensor, wherein the detection element is buried in a vibration-proof rubber layer in which a liquid rubber material is filled and cured in the casing. 2. The angular velocity sensor according to claim 1 , wherein the anti-vibration rubber layer is provided with a thickness of 5 to 10 mm between the inner wall surface of the casing and the detection element . The angular velocity sensor according to claim 1, wherein the vibration-proof rubber layer is made of silicone rubber . A method of manufacturing an angular velocity sensor in which a detection element is provided in a housing so as to receive vibration in a detection frequency range, and a signal processing circuit board for processing a signal from the detection element is fixedly provided.
A flexible board on which the detection element is mounted on the upper surface is connected in a suspended state below the signal processing circuit board,
Mounting the signal processing circuit board in the housing;
A method for manufacturing an angular velocity sensor, wherein a vibration-proof rubber layer is formed by filling and curing a liquid rubber material in the casing so that the detection element is buried. 5. The method of manufacturing an angular velocity sensor according to claim 4, wherein the casing is filled with the liquid rubber material by natural flow . Method of manufacturing an angular velocity sensor according to claim 4 or 5 further characterized in that the lower surface side of the front Symbol flexible substrate has a smooth surface. The angular velocity sensor according to any one of claims 4 to 6 , wherein the flexible substrate has a symmetrical shape in the front-rear direction and the left-right direction, and the detection element is mounted at a central portion thereof. Method. 8. The method of manufacturing an angular velocity sensor according to claim 7, wherein a weight member is attached to a central portion of the flexible substrate.

Images