Acceleration sensing apparatus

A collision sensing apparatus includes an acceleration sensor, first and second connector terminals, reference connector terminals and leads. The acceleration sensor is shaped into a square form. First and second contacts are provided in two diagonally opposed corner portions of the sensor. Reference contacts are arranged in the other two diagonally opposed corner portions of the sensor. The first and second connector terminals are opposed to the first and second contacts, respectively. The reference connector terminals are opposed to the reference contacts, respectively. The leads connect the first and second connector terminals and the reference connector terminals to the first and second contacts and the reference contacts.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by reference Japanese Patent Application No. 2005-189666 filed on Jun. 29, 2005 and Japanese Patent Application No. 2005-261151 filed on Sep. 8, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sensing apparatus, which senses a physical displacement in a predetermined direction.

2. Description of Related Art

An air bag system is known as an occupant protective apparatus, which protects an occupant of a vehicle. The air bag system may include a plurality of sensing apparatuses, which sense an impact applied to the vehicle. When the vehicle collides, an air bag of the air bag system is deployed based on a sensed result of the sensing apparatuses to protect the occupant of the vehicle. For example, Japanese Unexamined Patent publication No. 2004-294419 (corresponding to US 2004/0201464 A1, the contents of which are incorporated herein by reference) discloses one such sensing apparatus, called a collision sensing apparatus, which is a sensing apparatus that can sense the impact applied to the vehicle.

The collision sensing apparatus includes a G sensor, a housing, connector terminals and leads. The G sensor is a sensor that outputs a signal, which corresponds to a degree of an applied acceleration. The G sensor includes a sensing device, a communication device and a power supply circuit, which are packaged into a single package. The housing is a case, which fixes the connector terminals and receives the G sensor. The connector terminals, which are made of metal and externally and electrically connect the G sensor, are molded integrally with the housing. Furthermore, a sensor receiving portion, which receives the G sensor, is formed in the housing. End portions of the connector terminals are exposed in the sensor receiving portion, and the G sensor is connected to the end portions of the connector terminals through the leads made of metal.

The above G sensor is designed to sense only the acceleration in a predetermined direction. Thus, the collision sensing apparatus can sense only the impact in the single direction. In general, in the air bag system, the air bag is deployed based on the impacts applied to the vehicle from the various directions. Therefore, the multiple impact sensing apparatuses need to be provided to correspond with the directions of the impacts, which need to be sensed. However, in some cases, due to a limited amount of available space on the vehicle, one or more of the collision sensing apparatuses cannot be installed in consistency with the corresponding sensing direction(s). In such a case, the orientation of the G sensor in the housing of the corresponding collision sensing apparatus needs be changed. At this time, the shapes of the connector terminals or the positions of contacts of the G sensor should be changed in response to the change in the orientation of the G sensor. These changes require a change in the molding die, thereby resulting in the increased costs. This will lead to the increased manufacturing costs of the collision sensing apparatuses.

SUMMARY OF THE INVENTION

The present invention addresses the above disadvantages. Thus, it is an objective of the present invention to provide a sensing apparatus, which enables a change in a sensing direction of a physical displacement with no or a little modification of components of the sensing apparatus at relatively low costs.

To achieve the objective of the present invention, there is provided a sensing apparatus, which includes a sensor, a first connector terminal, a second connector terminal, at least one reference connector terminal and a plurality of leads. The sensor senses a physical acceleration in a predetermined direction and is shaped into a quadrangular form. The sensor includes a first input/output contact, a second input/output contact and at least one reference contact. The first input/output contact and the second input/output contact are arranged in two diagonally opposed corner portions, respectively, of the sensor. The at least one reference contact is arranged in at least one of the other two diagonally opposed corner portions of the sensor. The first connector terminal conducts an input/output signal to the first input/output contact and is arranged such that a sensor side end of the first connector terminal is opposed to one of two adjacent sides of the sensor, which come together at the corner portion of the sensor where the first input/output contact is arranged. The second connector terminal conducts an input/output signal to the second input/output contact and is arranged such that a sensor side end of the second connector terminal is opposed to an opposite side of the sensor that is opposite from the side of the sensor, to which the sensor side end of the first connector terminal is opposed. The at least one reference connector terminal conducts a reference signal to the at least one reference contact and is arranged such that a sensor side end of each of the at least one reference connector terminal is opposed to a corresponding one of two mutually opposed sides of the sensor, to which the first connector terminal and the second connector terminal are not opposed. The leads connect the first input/output contact, the second input/output contact and the at least one reference contact to the first connector terminal, the second connector terminal and the at least one reference connector terminal, respectively.

The quadrangular form of the sensor may be a square form having the sides of generally equal size. The at least one reference contact may include two reference contacts, which are arranged in the other two diagonally opposed corner portions, respectively, of the sensor. The at least one reference connector terminal may include two reference connector terminals, which conduct the reference signal to the reference contacts, respectively, and are arranged such that the sensor side ends of the reference connector terminals are opposed to the two mutually opposed sides, respectively, of the sensor. An extent of the first connector terminal, which is measured in a direction parallel to the side of the sensor that is adjacent to and is opposed to the first connector terminal, may be generally equal to an extent of the side of the sensor that is adjacent to and is opposed to the first connector terminal. An extent of the second connector terminal, which is measured in a direction parallel to the side of the sensor that is adjacent to and is opposed to the second connector terminal, may be generally equal to an extent of the side of the sensor that is adjacent to and is opposed to the second connector terminal. An extent of one of the reference connector terminals, which is measured in a direction parallel to the side of the sensor that is adjacent to and is opposed to the one of the reference connector terminals, may be generally equal to an extent of the side of the sensor that is adjacent to and is opposed to the one of the reference connector terminals. An extent of the other one of the reference connector terminals, which is measured in a direction parallel to the side of the sensor that is adjacent to and is opposed to the other one of the reference connector terminals, may be generally equal to an extent of the side of the sensor that is adjacent to and is opposed to the other one of the reference connector terminals.

To achieve the objective of the present invention, there is also provided a sensing apparatus, which includes a sensor, a first connector terminal, a second connector terminal, at least one reference connector terminal and a plurality of leads. The sensor senses a physical acceleration in a predetermined direction and is shaped into a quadrangular form. The sensor includes a first input/output contact, a second input/output contact and at least one reference contact. The first input/output contact and the second input/output contact are arranged in two diagonally opposed corner portions, respectively, of the sensor. The at least one reference contact is arranged in at least one of the other two diagonally opposed corner portions of the sensor. The first connector terminal conducts an input/output signal to the first input/output contact and is arranged such that a sensor side end of the first connector terminal is opposed to one of two adjacent sides of the sensor, which come together at the corner portion of the sensor where the first input/output contact is arranged. The second connector terminal conducts an input/output signal to the second input/output contact and is arranged such that a sensor side end of the second connector terminal is opposed to an opposite side of the sensor that is opposite from the side of the sensor, to which the sensor side end of the first connector terminal is opposed. The at least one reference connector terminal conducts a reference signal to the at least one reference contact and is arranged such that a sensor side end of each of the at least one reference connector terminal is opposed to a corresponding one of: the side of the sensor, to which the first connector terminal is opposed; and the side of the sensor, to which the second connector terminal is opposed. The leads connect the first input/output contact, the second input/output contact and the at least one reference contact to the first connector terminal, the second connector terminal and the at least one reference connector terminal, respectively.

The quadrangular form of the sensor may be a square form having the sides of generally equal size. The at least one reference contact may include two reference contacts, which are arranged in the other two diagonally opposed corner portions, respectively, of the sensor. The at least one reference connector terminal may include two reference connector terminals, which conduct the reference signal to the reference contacts, respectively, and are arranged such that the sensor side end of one of the reference connector terminals is opposed to the side of the sensor, to which the first connector terminal is opposed, and the sensor side end of the other one of the reference connector terminals is opposed to the side of the sensor, to which the second connector terminal is opposed. An extent of the first connector terminal, which is measured in a direction parallel to the side of the sensor that is opposed to the first connector terminal, may be generally equal to an extent of the side of the sensor that is opposed to the first connector terminal. An extent of the second connector terminal, which is measured in a direction parallel to the side of the sensor that is opposed to the second connector terminal, may be generally equal to an extent of the side of the sensor that is opposed to the second connector terminal. An extent of the one of the reference connector terminals, which is measured in a direction parallel to the side of the sensor that is opposed to the first connector terminal, may be generally equal to the extent of the side of the sensor that is opposed to the first connector terminal. An extent of the other one of the reference connector terminals, which is measured in a direction parallel to the side of the sensor that is opposed to the second connector terminal, may be generally equal to the extent of the side of the sensor that is opposed to the second connector terminal.

FIRST EMBODIMENT

A sensing apparatus according to a first embodiment of the present invention is formed as a component of an air bag system and is implemented as a collision sensing apparatus, which senses a collision of a vehicle.FIG. 1shows a structure of the air bag system.

The structure of the air bag system will be described with reference toFIG. 1. As shown inFIG. 1, the air bag system1includes an air bag ECU2, communication buses3,4, collision sensing apparatuses5–8(sensing apparatuses), a front driver seat side air bag9, a front passenger seat side air bag10and side air bags11. A battery13is connected to the air bag ECU2through an ignition switch12.

The air bag ECU2deploys the front driver seat side air bag9, the front passenger seat side air bag10and/or the side air bag(s)11based on the measured acceleration, which is sensed by an internal sensor, and also the measured acceleration(s), which is sensed by the collision sensing apparatuses5–8. The air bag ECU2is positioned generally in the center of the vehicle.

The communication buses3,4are signal lines, which supply the power source voltage from the air bag ECU2to the collision sensing apparatuses5–8and transmit the commands and data between the air bag ECU2and the collision sensing apparatuses5–8. The respective communication bus3,4includes a reference line3a,4aand a transmission line3b,4b.

Each of the collision sensing apparatuses5–8senses the acceleration in a corresponding predetermined direction at the corresponding part of the vehicle and transmits the sensed result as the acceleration data through the corresponding communication bus3,4based on a data transmission request supplied from the air bag ECU2. Each collision sensing apparatus5–8is arranged in the corresponding crash zone of the vehicle and senses the acceleration in the fore-and-aft direction or the left-to-right direction of the vehicle. The collision sensing apparatuses5,6are connected in series to the air bag ECU2through the communication bus3. The collision sensing apparatuses7,8are connected in series to the air bag ECU2through the communication bus4.

The front driver seat side air bag9, the front passenger seat side air bag10and the side air bags11are protective devices, which are deployed based on the corresponding command from the air bag ECU2to protect a vehicle occupant(s). The front driver seat side air bag9is provided in front of the front driver seat, and the front passenger seat side air bag10is provided in front of the front passenger seat. The side air bags11are arranged on the lateral side of the front driver seat and the lateral side of the front passenger seat, respectively.

Now, the structure of the collision sensing apparatuses5–8will be described with reference toFIGS. 2 to 5. The collision sensing apparatuses5–8have the same structure, so that only the collision sensing apparatus5will be described below. As shown inFIGS. 2 and 3, the collision sensing apparatus5includes an acceleration sensor50(sensor), a connector case51, a first connector terminal52(a first connector contact), a second connector terminal53(a second connector contact), two reference connector terminals54,55(reference connector contacts) and four leads56–59.

The acceleration sensor50is the sensor that senses the acceleration in the predetermined direction and transmits the sensed acceleration data based on the data transmission request command supplied from the air bag ECU2. As shown inFIG. 3, the acceleration sensor50is shaped into a square form having four sides of generally equal size. The acceleration sensor50includes a first contact50a(a first input/output contact) and a second contact50b(a second input/output contact) at two diagonally opposed corner portions, respectively, of the acceleration sensor50. The acceleration sensor50further includes two reference contacts50c,50d(reference contacts) at the other two diagonally opposed corner portions, respectively, of the acceleration sensor50. The acceleration sensor50receives the data transmission request command, which is inputted to the first contact50aand determines whether the acceleration sensor50itself is a communication subject. When it is determined that the acceleration sensor50itself is the communication subject, the acceleration sensor50transmits the sensed acceleration data from the first contact50a. Furthermore, the acceleration sensor50transmits the data transmission request command, which is inputted to the first contact50a, from the second terminal50b. Furthermore, the acceleration sensor50transmits the data, which is inputted to the second contact50b, from the first contact50a. The reference contacts50c,50dare contacts, which are used to communicate a reference signal that serves as a reference of the signal transmitted through the first and second contacts50a,50b. Furthermore, the reference contacts50c,50dare interconnected with each other in the interior of the acceleration sensor50. Although not illustrated in the drawings, the acceleration sensor50includes a sensing device and a communicating device (an outputting device). The sensing device is a block that senses the acceleration in the predetermined direction (in accordance with a physical displacement of a sensing portion of the sensing device in the predetermined direction). The communicating device is a block that controls transmission and reception of data, like ones described above. The sensing device and the communicating device are packaged into a signal package.

As shown inFIGS. 2 and 3, the connector case51is a resin case, which fixes the first and second connector terminals52,53and the reference connector terminals54,55and receives the acceleration sensor50. The first and second connector terminals52,53and the reference connector terminals54,55are formed integrally with the connector case51. Furthermore, the connector case51includes an acceleration sensor receiving portion (an acceleration sensor receiving chamber)51a, which receives the acceleration sensor50. Furthermore, a cylindrical metal bush51bis integrally molded into an end portion of the connector case51. The metal bush51breceives a bolt therethrough to install the connector case51to the vehicle.

The first and second connector terminals52,53and the reference connector terminals54,55are plate-shaped conductors that connect the acceleration sensor50, which is connected to the terminals52–54through the leads56–59, to the communication bus3ofFIG. 1. The first connector terminal52connects the first contact50aof the acceleration sensor50to the transmission line3blocated on the air bag ECU2side. The second connector terminal53connects the second contact50bof the acceleration sensor50to the transmission line3bon the collision sensing apparatus6side. Furthermore, the reference connector terminals54,55connect the reference contacts50c,50dof the acceleration sensor50to the reference line3aon the air bag ECU2side and the reference line3aon the collision sensing apparatus6side, respectively.

As shown inFIGS. 4A to 4C, the first connector terminal52includes a bottom portion52a, two lateral portions52b,52cand a contacting portion52d. The lateral portions52b,52cextend from opposed ends of the bottom portion52ain a direction perpendicular to a plane of the bottom portion52a. The contacting portion52dextends generally from the center of the bottom portion52ain the direction perpendicular to the plane of the bottom portion52aon the opposite side, which is opposite to the lateral portions52b,52c. Projections52e,52fare provided to ends of the lateral portions52b,52c. Furthermore, a space between the projections52e,52fis generally equal to a length of one side of the acceleration sensor50. Similar to the first connector terminal52, each of the second connector terminal53and the reference connector terminals54,55has a base portion53a–55a, lateral portions53b–55b,53c–55cand a contacting portion53d–55d. Furthermore, projections53e–55e,53f–55fare provided to ends of the lateral portions53b–55b,53c–55cof each of the second connector terminal53and the reference connector terminals54,55. The second connector terminal53and the reference connector terminals54,55have the same shape as that of the first connector terminal52except the shape of the contacting portion and therefore will not be described further.

As shown inFIG. 3, the first connector terminal52, the second connector terminal53and the reference connector terminals54,55are molded integrally with the connector case51in such a manner that each of the projections52e–55e,52f–55fof the first connector terminal52, the second connector terminal53and the reference connector terminals54,55is opposed to the corresponding one of the first contact50a, the second contact50band the reference contacts50c,50dwhile the corresponding side (side edge) of the acceleration sensor50is interposed therebetween. Furthermore, the acceleration sensor50side end(s) of each of the first connector terminal52, the second connector terminal53and the reference connector terminals54,55(the acceleration sensor50side ends of the lateral portions52b–55b,52c–55cof each of the first connector terminal52, the second connector terminal53and the reference connector terminals54,55, which are exposed in an interior space of the acceleration sensor receiving portion51aof the connector case51, or the acceleration sensor50side end of the bottom portion of each of the first connector terminal52, the second connector terminal53and the reference connector terminals54,55,) are generally parallel to the opposed side of the acceleration sensor50and are opposed to the corresponding two, respectively, of the first contact50a, the second contact50band the reference contacts50c,50d.

The leads56–59are plate shaped conductors, which connect the first contact50a, the second contact50band the reference contacts50c,50dof the acceleration sensor50to the first connector terminal52, the second connector terminal53and the reference connector terminals54,55, respectively. As shown inFIGS. 5A–5C, the lead56includes an acceleration sensor connection56a, a connector terminal connection56band an interconnecting portion56c. The interconnecting portion56cconnects between the acceleration sensor connection56aand the connector terminal connection56b. A through hole56dpenetrates through the connector terminal connection56b. Similar to the lead56, each of the other leads57–59includes an acceleration sensor connection57a–59a, a connector terminal connection57b–59band an interconnecting portion57c–59c. A through hole57d–59dpenetrates through the connector terminal connection57b–59b. The shapes of the leads57–59are the same as that of the lead56and therefore will not be described further.

As shown inFIG. 3, the acceleration sensor connection56aof the lead56is soldered to the first contact50aof the acceleration sensor50. The connector terminal connection56bof the lead56is soldered to the first connector terminal52in a state where the through hole56dof the connector terminal connection56breceives the projection52eof the first connector terminal52. The acceleration sensor connection57aof the lead57is soldered to the second contact50bof the acceleration sensor50. The connector terminal connection57bof the lead57is soldered to the second connector terminal53in a state where the through hole57dof the connector terminal connection57breceives the projection53eof the second connector terminal53. The acceleration sensor connections58a,59aof the leads58,59are soldered to the reference contacts50c,50d, respectively, of the acceleration sensor50. The connector terminal connections58b,59bof the leads58,59are soldered to the reference connector terminals54,55, respectively, in a state where the through hole58d,59dof each connector terminal connection58b,59breceives the projection54e,55eof the corresponding reference connector terminal54,55.

Next, with reference toFIGS. 6 and 7, there will be described another case where the sensing direction A of the acceleration with respect to the connector case51is changed by 90 degrees from the one shown inFIGS. 2 and 3. In this case, the orientation of the acceleration sensor50shown inFIG. 3is rotated by 90 degrees in the clockwise direction. Due to the rotation of the acceleration sensor50, for example, the lead56, which is connected to the projection52eof the first connector terminal52shown inFIG. 2, is now connected to the projection52fof the first connector terminal52, as shown inFIG. 6.

As shown inFIG. 7, the acceleration sensor connection56aof the lead56is soldered to the first contact50aof the acceleration sensor50. The connector terminal connection56bof the lead56is soldered to the first connector terminal52in a state where the through hole56dof the connector terminal connection56breceives the projection52fof the first connector terminal52. The acceleration sensor connection57aof the lead57is soldered to the second contact50bof the acceleration sensor50. The connector terminal connection57bof the lead57is soldered to the second connector terminal53in a state where the through hole57dof the connector terminal connection57breceives the projection53fof the second connector terminal53. The acceleration sensor connections58a,59aof the leads58,59are soldered to the reference contacts50c,50d, respectively, of the acceleration sensor50. The connector terminal connections58b,59bof the leads58,59are soldered to the reference connector terminals54,55, respectively, in a state where the through hole58d,59dof each connector terminal connection58b,59breceives the projection54f,55fof the corresponding reference connector terminal54,55. That is, the acceleration sensor50is rotated, and the connecting positions of the leads56–59with respect to the first connector terminal52, the second connector terminal53and the reference connector terminals54,55are changed. With this simple modification, the sensing direction A of the acceleration can be changed by 90 degrees.

Next, an operation of the air bag system1will be described in detail with reference toFIG. 1. With reference toFIG. 1, when the ignition switch12is turned on, the output voltage of the battery13is supplied, so that the air bag ECU2starts its operation. The air bag ECU2supplies the power source voltage to the collision sensing apparatuses5–8through the communication buses3,4. When the power source voltage is supplied, the collision sensing apparatuses5–8start its operation. Thereafter, the air bag ECU2sequentially and serially transfers the data transmission request command to the collision sensing apparatuses5–8through the communication buses3,4. Each collision sensing apparatus5–8receives the data transmission request command and determines whether the collision sensing apparatus5–8itself is the subject of the communication (the communication subject), to which the data transmission request command is addressed. When it is determined that the collision sensing apparatus5–8itself is the communication subject, the collision sensing apparatus5–8transmits the sensed acceleration data to the air bag ECU2. The transmission of the sensed acceleration data from the collision sensing apparatuses5–8to the air bag ECU2is performed sequentially and serially. The air bag ECU2deploys the front driver seat side air bag9, the front passenger seat side air bag10and/or the side air bag(s)11based on the measured acceleration, which is sensed by the internal sensor, and also the measured acceleration(s), which is sensed by the collision sensing apparatuses5–8, thereby protecting the vehicle occupant(s).

Next, advantages of the first embodiment will be described. According to the first embodiment, the sensing direction A of the acceleration can be simply changed by rotating the acceleration sensor50and by changing the installation orientations of the leads56–59without a need for modifying the acceleration sensor50, the connector case51, the first connector terminal52, the second connector terminal53, the reference connector terminals54,55and the leads56–59. Thus, the versatile collision sensing apparatuses can be constructed at the relatively low costs regardless of the sensing direction A of the acceleration.

Furthermore, according to the first embodiment, each of the projections of the first connector terminal52, the second connector terminal53and the reference connector terminals54,55is opposed to the corresponding one of the first contact50a, the second contact50band the reference contacts50c,50dwhile the corresponding side (the side edge) of the acceleration sensor50is interposed therebetween. In this way, the lengths of the leads56–59can be reduced. Therefore, the collision sensing apparatuses can be constructed at the relatively low costs.

Furthermore, according to the first embodiment, the sensed acceleration data is transmitted from the first contact50abased on the data transmission request command inputted from the first contact50a, so that the acceleration data can be reliably outputted. The data transmission request command, which is inputted to the first contact50a, is transmitted from the second contact50b, and the data, which is inputted to the second contact50b, is transmitted from the first contact50a. In this way, the signals can be reliably communicated between each upstream side collision sensing apparatus and the corresponding downstream side collision sensing apparatus (seeFIG. 1). In the acceleration sensor50, the sensing device, which senses the acceleration, and the communicating device (the outputting device) are packaged into the single package, so that the collision sensing apparatus can be made compact.

SECOND EMBODIMENT

Next, the collision sensing apparatus according to a second embodiment will be described.FIG. 8shows a cross sectional view of the collision sensing apparatus, andFIG. 9shows the cross sectional view of the collision sensing apparatus, in which the sensing direction A of the acceleration is changed from that of the collision sensing apparatus shown inFIG. 8. The collision sensing apparatus of the second embodiment is a modification of the collision sensing apparatus of the first embodiment, in which the shapes of the connector terminals and of the leads are partially modified from those of the first embodiment. The operation of the collision sensing apparatus of the second embodiment is substantially the same as that of the collision sensing apparatus of the first embodiment. In the following description, only the connector terminals and the leads, which are different from those of the first embodiment, will be described, and the other common components other than the connector terminals and the leads will not be described further. Furthermore, the components, which are the same as those of the first embodiment, will be indicated by the same numerals.

First, the structure will be described with reference toFIGS. 8 and 9. As shown inFIG. 8, the first connector terminal520is formed by modifying the first connector terminal52of the first embodiment in such a manner that the lateral portion52bof the first connector terminal52is elongated in the longitudinal direction thereof and is bent toward the other lateral portion52cside. The second connector terminal530and the reference connector terminals540,550are formed by modifying the second connector terminal53and the reference connector terminals54,55of the first embodiment in a manner similar to that of the first connector terminal520described above. The first connector terminal520, the second connector terminal530and the reference connector terminals540,550are molded integrally with the connector case51in the following manner. That is, the acceleration sensor50side end of each of the first connector terminal520, the second connector terminal530and the reference connector terminals540,550(more specifically, the acceleration sensor50side end of the exposed portion, i.e., the acceleration sensor50side end of the elongated portion of the one lateral portion, which is bent toward the other lateral portion, of each of the first connector terminal520, the second connector terminal530and the reference connector terminals540,550exposed in an interior space of the acceleration sensor receiving portion51aof the connector case51) is generally parallel to the opposed side of the acceleration sensor50and are opposed to the corresponding two, respectively, of the first contact50a, the second contact50band the reference contacts50c,50d.

The lead560is formed by modifying the lead56of the first embodiment in such a manner that the width (measured in the left-right direction inFIG. 8) of the connector terminal connection56bis reduced, and the through hole56dis eliminated from the connector terminal connection56b. The leads570,580,590are formed by modifying the leads57–59of the first embodiment in a manner similar to that of the lead560described above. The acceleration sensor connection560aof the lead560is soldered to the first contact50aof the acceleration sensor50. The connector terminal connection560bof the lead560is soldered to a left end portion of the first connector terminal520, which is opposed to the first contact50ainFIG. 8. The acceleration sensor connection570aof the lead570is soldered to the second contact50bof the acceleration sensor50. The connector terminal connection570bof the lead570is soldered to a right end portion of the second connector terminal530, which is opposed to the second contact50binFIG. 8. The acceleration sensor connections580a,590aof the leads580,590are soldered to the reference contacts50c,50d, respectively, of the acceleration sensor50. The connector terminal connection580bof the lead580is soldered to a lower end portion of the reference connector terminal540, which is opposed to the reference contact50cinFIG. 8. Furthermore, the connector terminal connection590bof the lead590is soldered to an upper end portion of the reference connector terminal550, which is opposed to the reference contact50dinFIG. 8.

Next, with reference toFIG. 9, there will be described the case where the sensing direction A of the acceleration with respect to the connector case51is changed by 90 degrees from the one shown inFIG. 8. In this case, the orientation of the acceleration sensor50shown inFIG. 8is rotated by 90 degrees in the clockwise direction.

As shown inFIG. 9, the acceleration sensor connection560aof the lead560is soldered to the first contact50aof the acceleration sensor50. The connector terminal connection560bof the lead560is soldered to a right end portion of the first connector terminal520, which is opposed to the first contact50ainFIG. 9. The acceleration sensor connection570aof the lead570is soldered to the second contact50bof the acceleration sensor50. The connector terminal connection570bof the lead570is soldered to a left end portion of the second connector terminal530, which is opposed to the second contact50binFIG. 9. The acceleration sensor connections580a,590aof the leads580,590are soldered to the reference contacts50c,50d, respectively, of the acceleration sensor50. The connector terminal connection580bof the lead580is soldered to an upper end portion of the reference connector terminal540, which is opposed to the reference contact50cinFIG. 9. Furthermore, the connector terminal connection590bof the lead590is soldered to a lower end portion of the reference connector terminal550, which is opposed to the reference contact50dinFIG. 9. Similar to the first embodiment, the acceleration sensor50is rotated, and the connecting positions of the leads560–590with respect to the first connector terminal520, the second connector terminal530and the reference connector terminals540,550are changed. With this simple modification, the sensing direction A of the acceleration can be changed by 90 degrees.

Next, advantages of the second embodiment will be described. According to the second embodiment, unlike the first embodiment, there is no need to place the projection of each connector terminal through the through hole of the corresponding lead, so that the assembling work can be more easily performed. Furthermore, according to the second embodiment, the connection surface area between each lead and the corresponding connector terminal is increased, so that the sufficient strength can be achieved, and the electrical reliability can be improved.

THIRD EMBODIMENT

Next, the collision sensing apparatus according to a third embodiment will be described.FIG. 10shows a cross sectional view of the collision sensing apparatus, andFIG. 11shows the cross sectional view of the collision sensing apparatus, in which the sensing direction A of the acceleration is changed from that of the collision sensing apparatus shown inFIG. 10. The collision sensing apparatus of the third embodiment is implemented by modifying the positions of the reference connector terminals and the shapes of the leads, which are connected to the reference connector terminals, of the collision sensing apparatus of the second embodiment. The operation of the collision sensing apparatus of the third embodiment is substantially the same as that of the collision sensing apparatus of the first and second embodiments. In the following description, only the reference connector terminals and the corresponding leads, which are different from those of the second embodiment, will be described, and the other common components other than the reference connector terminals and the corresponding leads will not be described further. Furthermore, the components, which are the same as those of the second embodiment, will be indicated by the same numerals.

First, the structure will be described with reference toFIGS. 10 and 11. As shown inFIG. 10, the reference connector terminals541,551of the third embodiment are implemented by changing the positions of the reference connector terminals540,550of the second embodiment. Due to the changes in the positions of the reference connector terminals, the shape of the contacting portion of each reference connector terminal is changed although the shape of the acceleration sensor side end of the reference connector terminal remains the same. The reference connector terminal541is molded integrally with the connector case51in such a manner that the acceleration sensor50side end of the reference connector terminal541exposed in the acceleration sensor receiving portion51ais placed below the second connector terminal530and is generally parallel to the second connector terminal530inFIG. 10. The reference connector terminal551is molded integrally with the connector case51in such a manner that the acceleration sensor50side end of the reference connector terminal551exposed in the acceleration sensor receiving portion51ais placed above the first connector terminal520and is generally parallel to the first connector terminal520inFIG. 10.

The leads581,591are implemented by modifying the leads580,590of the second embodiment in such a manner that the interconnecting portion of each of the leads580,590is elongated in the longitudinal direction thereof due to the positioning of the reference connector terminals541,551further away from the acceleration sensor50. The acceleration sensor connection560aof the lead560is soldered to the first contact50aof the acceleration sensor50. The connector terminal connection560bof the lead560is soldered to a left end portion of the first connector terminal520, which is opposed to the first contact50ainFIG. 10. The acceleration sensor connection570aof the lead570is soldered to the second contact50bof the acceleration sensor50. The connector terminal connection570bof the lead570is soldered to a right end portion of the second connector terminal530, which is opposed to the second contact50binFIG. 10. The acceleration sensor connections581a,591aof the leads581,591are soldered to the reference contacts50c,50d, respectively, of the acceleration sensor50. The connector terminal connection581bof the lead581is soldered to a left end portion of the reference connector terminal541, which is opposed to the reference contact50cinFIG. 10. Furthermore, the connector terminal connection591bof the lead591is soldered to a right end portion of the reference connector terminal551, which is opposed to the reference contact50dinFIG. 10. The leads581,591are configured such that the leads581,591do not contact the first connector terminal520and the second connector terminal530.

Next, with reference toFIG. 11, there will be described the case where the sensing direction A of the acceleration with respect to the connector case51is changed by 90 degrees from the one shown inFIG. 10. In this case, the orientation of the acceleration sensor50shown inFIG. 10is rotated by 90 degrees in the clockwise direction. The acceleration sensor connection560aof the lead560is soldered to the first contact50aof the acceleration sensor50. The connector terminal connection560bof the lead560is soldered to a right end portion of the first connector terminal520, which is opposed to the first contact50ainFIG. 11. The acceleration sensor connection570aof the lead570is soldered to the second contact50bof the acceleration sensor50. The connector terminal connection570bof the lead570is soldered to a left end portion of the second connector terminal530, which is opposed to the second contact50binFIG. 11. The acceleration sensor connections581a,591aof the leads581,591are soldered to the reference contacts50c,50d, respectively, of the acceleration sensor50. The connector terminal connection581bof the lead581is soldered to a left end portion of the reference connector terminal551, which is opposed to the reference contact50cinFIG. 11. Furthermore, the connector terminal connection591bof the lead591is soldered to a right end portion of the reference connector terminal541, which is opposed to the reference contact50dinFIG. 11. Similar to the second embodiment, the acceleration sensor50is rotated, and the connecting positions of the leads560,570,581,591with respect to the first connector terminal520, the second connector terminal530and the reference connector terminals541,551are changed. With this simple modification, the sensing direction A of the acceleration can be changed by 90 degrees.

Next, advantages of the third embodiment will be described. According to the third embodiment, unlike the first embodiment, there is no need to place the projection of each connector terminal through the through hole of the corresponding lead, so that the assembling work can be more easily performed. Furthermore, inFIGS. 10 and 11, the first connector terminal520, the second connector terminal530and the reference connector terminals541,551are arranged only at the upper side or the lower side of the acceleration sensor50, so that the size of the collision sensing apparatus in the left-to-right direction can be limited to make the collision sensing apparatus compact.

FOURTH EMBODIMENT

Next, the acceleration sensing apparatus according to a fourth embodiment will be described.FIG. 12is a cross sectional view of the acceleration sensor50of the fourth embodiment, andFIG. 13is a top view of the acceleration sensor50shown inFIG. 12.FIG. 14is a flowchart showing manufacturing steps S10–S90of a collision sensing apparatus, which has an acceleration sensor that includes a communication chip (an outputting device) and a sensor chip (a sensing device) packaged into a single package.FIG. 15is a flowchart showing manufacturing steps S110–S170of the collision sensing apparatus according to the fourth embodiment. The collision sensing apparatus of the fourth embodiment is a modification of the collision sensing apparatus of the first embodiment, in which the acceleration sensor is modified. The rest of the structure and operation of the collision sensing apparatus of the fourth embodiment other than the acceleration sensor are the same as those of the collision sensing apparatus of the first embodiment. In the following description, only the acceleration sensor, which is different from that of the first embodiment, will be described, and the other common components other than the acceleration sensor will not be described further. Furthermore, the components, which are the same as those of the first embodiment, will be indicated by the same numerals.

As shown inFIGS. 12 and 13, the acceleration sensor50(the sensor) includes a ceramic substrate50e, a communication chip (an outputting device)50f, a sensor chip (a sensing device)50g, a power supply element (a power supply device)50h, a noise limiting element (a noise reducing device)50iand a cover50j.

The ceramic substrate50eis a substrate, which has an n-shaped cross section and a square top surface and on which the communication chip50f, the sensor chip50g, the power supply element50hand the noise limiting element50iare arranged and are electrically connected. The first contact50aand the second contact50bare arranged at two diagonally opposed corner portions, respectively, of the square top surface of the ceramic substrate50e. Furthermore, the reference contacts50c,50dare arranged at the other two diagonally opposed corner portions, respectively, of the square top surface of the ceramic substrate50e.

The communication chip50fis a chip that controls transmission and reception of the data. The communication chip50fis fixed to the bottom surface of the ceramic substrate50einFIG. 12and is connected to the first contact50a, the second contact50band the reference contacts50c,50dby the wire bonding50kvia through holes and the pattern formed in the ceramic substrate50e.

The sensor chip50gis a chip that senses the acceleration in a predetermined direction. The sensor chip50gis fixed to the bottom surface of the communication chip50finFIG. 12and is connected to the communication chip50fvia wire bonding50l.

The power supply element50his an element that stably supplies the electric power to the communication chip50fand the sensor chip50gand may be, for example, a capacitor that charges electric power. The noise limiting element50iis an element that reduces electrical noises applied to the communication chip50fand the sensor chip50g. The power supply element50hand the noise limiting element50iare connected to the communication chip50fand the sensor chip50gthrough the pattern formed on the ceramic substrate50e.

The cover50jis a square metal plate, which covers an opening of the ceramic substrate50e. The cover50jis connected to the ceramic substrate50ethrough a connecting member50m. Therefore, the communication chip50f, the sensor chip50g, the power supply element50hand the noise limiting element50iare sealed by the ceramic substrate50eand the cover50j.

As described above, the communication chip50f, the sensor chip50g, the power supply element50hand the noise limiting element50iare packaged into the single package using the ceramic substrate50eas its central component.

Next, advantages will be described. According to the fourth embodiment, the number of temperature tests can be reduced in the manufacturing process, so that the collision sensing apparatus can be constructed at the relatively low costs. The output of the collision sensing apparatus changes depending on the temperature. Thus, the temperature test is performed in the manufacturing process to determine whether a change in the output of the collision sensing apparatus is within an acceptable range. In the case ofFIG. 14, the communication chip and the sensor chip are packaged into the single package to form the acceleration sensor (see steps S10–S40). In such a case, as shown inFIG. 14, the temperature test is performed at step S30on the acceleration sensor, which is formed as the single package. Furthermore, the temperature test is performed at step S80once again on the collision sensing apparatus after installation of the power supply element and the noise limiting element into the collision sensing apparatus (see steps S50–S90). This additional temperature test is performed to determine the influence of the temperature on the power supply element and the noise limiting element. That is, the temperature test needs to be performed twice. In contrast, when the communication chip50f, the sensor chip50g, the power supply element50hand the noise limiting element50iare packaged into the single package using the ceramic substrate50eas its central component, the temperature test needs to be performed only once at step S130, as shown inFIG. 15. Accordingly, the number of temperature test steps can be reduced in the manufacturing process, so that the collision sensing apparatus can be constructed at the relatively low costs.

In the fourth embodiment, the communication chip50f, the sensor chip50g, the power supply element50hand the noise limiting element50iare sealed by the ceramic substrate50eand the cover50j. However, the present invention is not limited to this construction. As shown inFIGS. 16 and 17, the power supply element50hand the noise limiting element50ineed not be sealed between the ceramic substrate50eand the cover50j. More specifically, the power supply element50hand the noise limiting element50imay be fixed to the top surface of the ceramic substrate50e, as shown inFIG. 16. Furthermore, as shown inFIGS. 18 and 19, a lead frame50n, to which the communication chip50f, the sensor chip50g, the power supply element50hand the noise limiting element50iare secured, may be integrally molded with a resin material to form the case50o. Here, the lead frame50nis a metal plate, which fixes and electrically connects the communication chip50f, the sensor chip50g, the power supply element50hand the noise limiting element50i. The ends of the lead frame50nare arranged in the top surface of the case50oas the first contact50a, the second contact50band the reference contacts50c,50d. The first contact50aand the second contact50bare arranged at two diagonally opposed corner portions of the top surface of the case50o, and the reference contacts50c,50dare arranged at the other two diagonally opposed corner portions of the top surface of the case50o. In this case too, the number of the temperature tests can be reduced in the manufacturing process, so that the collision sensing apparatus can be constructed at the relatively low costs.

In the first to third embodiments, the acceleration sensor has the square shape (the square form). However, the present invention is not limited to this. The acceleration sensor only needs to have a quadrangular shape (a quadrangular form). For example, the acceleration sensor may have a rectangular shape. In this instance, the shapes of the connector terminals and of the leads should be optimally set, and thereby the sensing direction of the acceleration can be changed with or without a small change in the components. Furthermore, in the first to third embodiments, the acceleration sensor includes the two reference contacts. However, the present invention is not limited to this. For instance, the acceleration sensor may include a single reference contact. Even in such a case, the advantages similar to those described above can be achieved. Furthermore, in the first to third embodiments, the leads are connected to the acceleration sensor and the connector terminals by the soldering. However, the present invention is not limited to this. For instance, the leads may be connected to the acceleration sensor and the connector terminals by welding. Further alternatively, the contacts of the acceleration sensor and the corresponding connector terminals may be connected together by wire bonding. That is, any type of connection can be made as long as it can electrically connect the acceleration sensor (more specifically, the contact of the acceleration sensor) to the corresponding connector terminals.

Furthermore, the acceleration sensor50of the fourth embodiment or its modification may be used as the acceleration sensor50of any of the first to third embodiments. In this way, the advantages similar to those of the fourth embodiment can be additionally achieved in any of the first to third embodiments.