Physical quantity measuring device

A plate-shaped circuit board configured to receive a detection signal from a detector is housed in a case and is held by a holder with a flat substrate surface thereof intersecting with a bottom surface of a cover member. The holder is attached to the cover member. The cover member includes a cover body, and elongated supporting portions projecting from the bottom surface of the cover body into the case. The supporting portions each include a pair of support projections that support one of opposite side surfaces of the circuit board along a projecting direction of the supporting portions. The holder includes a flat portion provided with engagement pieces engageable with a second substrate.

The entire disclosure of Japanese Patent Application No. 2014-063679 filed Mar. 26, 2014 is expressly incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a physical quantity measuring device for measuring a pressure and/or any other physical quantity of a fluid to be measured.

BACKGROUND ART

In some pressure transmitters and other physical quantity measuring devices, a circuit board receives a detection signal from a detector for detecting a physical quantity, and a signal from the circuit board is outputted to an external device or to a display.

In typical examples of the above physical quantity measuring devices, a circuit board is disposed in parallel with a bottom surface of a holder, and an outer periphery of the circuit board is pressed at regular intervals using a plurality of engagement portions or claws of the holder (Patent Literature 1: JP-A-2005-300186, Patent Literature 2: JP-A-10-318871, Patent Literature 3: JP-A-2007-155505 and Patent Literature 4: JP-A-11-351994).

In other typical examples, a circuit board is disposed perpendicular to a bottom surface of a holder, the circuit board having a first end bonded to a joint-side support body and a second end bonded to a connector-side support body (Patent Literature 5: JP-A-2013-205418 and Patent Literature 6: JP-A-9-138170).

The typical examples of Patent Literatures 1 to 4 require the outer periphery of the circuit board to be held relative to the bottom surface of the holder at an accurate position using the plurality of engagement portions and claws. It is complicated to attach the circuit board at the accurate position.

Further, when the physical quantity measuring device is used in ship or the like, the circuit board may be displaced due to the rolling of the ship or the like, but it is doubtful whether or not necessary measures are taken to deal with a vibration problem in the typical examples.

Specifically, in the typical examples of Patent Literatures 1 to 4, the circuit board, which is pressed using the engagement portions or claws, may be displaced or detached from the engagement portions or claws in response to a vibration applied to the device.

In the typical examples of Patent Literatures 5, 6, both ends of the circuit board each need to be bonded to the holder or the joint, which results in an inefficient device assembly.

Especially in the typical example of Patent Literature 5, the end of the circuit board needs to be machined into a joint shape and bonded to the support body, which also results in an inefficient device assembly.

SUMMARY OF THE INVENTION

An object of the invention is to provide an easy assembling physical quantity measuring device capable of reliably holding a circuit board relative to a cover member.

According to an aspect of the invention, a physical quantity measuring device includes: a cylindrical case having a first open end and a second open end; a cover member attached to the first open end of the case, the cover member having a bottom surface; a detector provided to the second open end of the case to detect a physical quantity; a plate-shaped circuit board configured to receive a detection signal from the detector; and a holder attached to the cover member to hold the circuit board in a manner that a flat surface of the circuit board intersects with the bottom surface, the holder including an engagement piece engageable with the circuit board, the cover member including: a cover body defining the bottom surface; and a supporting portion projecting from the bottom surface into the case, the supporting portion including a pair of support projections configured to support opposite side surfaces of the circuit board along a projecting direction of the supporting portion.

In the above aspect, the side surfaces of the circuit board on both lateral sides are supported by the support projections of the cover member, and then the engagement piece is engaged with the circuit board. In the above state, the cover member, the holder and the circuit board are untied. While the circuit board is present in the case provided with the detector, the case and the cover member are bonded to each other.

With the above arrangement, the two surfaces of the circuit board (i.e., the side surfaces on both lateral sides) are supported by the supporting portion in the above aspect, while the circuit board is supported relative to the bottom surface of the cover member by the holder, so that it is unnecessary to bond the circuit board to a detector-side member. An assembly process of the physical quantity measuring device can thus be simplified. Further, since the side surfaces of the circuit board on both lateral sides are supported by the support projections, the circuit board can be accurately positioned to the bottom surface. Further, since the holder is directly attached to the cover member or indirectly attached to the cover member via an intervening member, and the circuit board is engaged with the holder using the engagement piece, the circuit board can be reliably held relative to the cover member without being displaced relative to the cover member irrespective of the rolling of the physical quantity measuring device.

In the above aspect, it is preferable that the supporting portion further include a claw provided to each of the support projections to prevent the circuit board from being detached from the bottom surface, and the holder further include a flat portion facing the bottom surface, the flat portion being provided with the engagement piece.

With the above arrangement, the side surfaces of the circuit board on both lateral sides are supported by the support projections of the cover body, and then the flat portion of the holder is inserted into a space between the circuit board and the bottom surface of the cover body to bring the engagement piece into engagement with the circuit board. Further, the claw serves to prevent the circuit board from falling off the support projections, so that displacement of the circuit board relative to the cover member is restrained and thus the circuit board is further reliably held relative to the cover member.

In the above aspect, it is preferable that the holder be held between the cover body and the case.

With the above arrangement, the holder can be easily and reliably attached to the cover member merely by inserting the holder between the cover body and the case.

In the above aspect, it is preferable that the case be crimped to fasten the cover body and the holder to each other.

With the above arrangement, the circuit board is stably supported relative to the cover member. Further, the assembly process can be simplified.

In the above aspect, it is preferable that the case and the holder be each made of a metal and the cover member be a made of a synthetic resin.

With the above arrangement, the holder and the case are in contact with each other, so that the circuit board can be easily grounded.

In the above aspect, it is preferable that the engagement piece include an engagement claw engageable with an engagement hole provided to the flat surface of the circuit board.

With the above arrangement, the engagement claw is engaged with the engagement hole of the circuit board, thereby preventing displacement of the circuit board in an in-plane direction of the flat surface of the circuit board.

In the above aspect, it is preferable that the engagement hole be provided adjacent to the bottom surface of the circuit board.

With the above arrangement, the engagement piece can be shortened, thereby reducing, for instance, breakage of the engagement piece. Alternatively, the engagement hole may be provided at a position remote from the bottom surface of the circuit board.

In this case, however, the engagement piece needs to be elongated and thus may be damaged, for instance, in attaching the circuit board.

In the above aspect, it is preferable that the flat surface of the circuit board include two flat surfaces intersecting with the side surfaces of the circuit board, the pair of support projections have mutually opposed surfaces functioning as a pair of first support surfaces facing peripheries of the flat surfaces of the circuit board, the pair of first support surfaces have edges connected by a second support surface facing one of the side surfaces of the circuit board, and the pair of first support surfaces and the second support surface define a support groove for supporting the circuit board.

With the above arrangement, the U-shaped support groove defined by the two first support surfaces and the second support surface serves to reliably support the circuit board.

DESCRIPTION OF EMBODIMENT(S)

An exemplary embodiment of the invention will be described with reference to the attached drawings.

FIGS. 1 to 5show an overall arrangement of a physical quantity measuring device according to the exemplary embodiment. The physical quantity measuring device according to the exemplary embodiment is used, for instance, in a ship or the like.

FIGS. 1 and 2show an exterior of the physical quantity measuring device.FIG. 3is a plan view of the physical quantity measuring device.FIG. 4schematically shows an arrangement of the physical quantity measuring device.FIG. 5is a sectional view of the physical quantity measuring device.

As shown inFIGS. 1 to 5, the physical quantity measuring device includes: a cylindrical case1; a joint2provided to a first open end of the case1; a cover member3provided to a second open end of the case1; a measuring mechanism4provided inside the case1; and a cap member5removably attachable to the cover member3.

The case1, which is machined from a metal cylindrical member, includes a body11and a fitting ring12integrally provided to a side of the body11corresponding to the second open end of the case1, the fitting ring12being fitted on the cover member3.

The fitting ring12has a diameter larger than that of the body11. A stepped portion13is defined between the body11and the fitting ring12along a case-diameter direction.

The joint2is a metal member including: a shaft21provided with an introduction hole2A through which a fluid to be measured is introduced; and a flange22radially extending from the center of the shaft21.

The shaft21has a first end provided with a thread23to be screwed into a mount (not shown).

As shown inFIGS. 4 and 5, the measuring mechanism4includes: a detector6provided to a second end of the shaft21of the joint2to detect a pressure of the fluid to be measured; a circuit board7disposed at a distance from the detector6; a signal transmitting member8connected to the circuit board7; and a holder9attached to the cover member3to hold the circuit board7.

The detector6is a metal member including: a cylindrical portion61bonded to the second end of the shaft21; and a diaphragm62integrally provided to an end of the cylindrical portion61opposite with the second end of the shaft21.

The diaphragm62includes a strain gauge (not shown) for detecting the pressure of the fluid to be measured introduced through the introduction hole2A.

The circuit board7includes: a substrate body70; and an electronic circuit unit71and an electronic adjusting unit72that are provided on the substrate body70.

The substrate body70is a rectangular plate member in a plan view and has a front surface on which a wiring pattern (not shown) is formed.

In the exemplary embodiment, the substrate body70includes: parallel first substrate701and second substrate702; and a connecting body73that connects the first substrate701and the second substrate702.

The electronic circuit unit71, which receives a detection signal from the detector6, is disposed on the front surface of the substrate body70. It should be noted that rear one of the substrates of the substrate body70is similarly provided with an electronic circuit unit (not shown). The strain gauge of the detector6and the electronic circuit unit71are electrically connected to each other through a wiring or the like (not shown).

The electronic adjusting unit72, which adjusts the electronic circuit unit71, includes two electronic adjusting units disposed on the front surface of the substrate body70. In the exemplary embodiment, the left one of the electronic adjusting units72shown inFIG. 4is intended for span adjustment (adjustment of output voltage) and the right one of the electronic adjusting units72shown inFIG. 4is intended for zero adjustment.

The electronic adjusting units72are each provided with an operable portion72A functioning as a trimmer near the cover member3. The operable portion72A is turned or pressed with a tool such as driver (not shown) to perform the adjustment.

The signal transmitting member8includes a cylindrical member80and a plurality of terminals81provided to the cylindrical member80. The terminals81are electrically connected to the circuit board7through a wiring or the like (not shown).

As shown inFIGS. 4 and 5, the cover member3, which is made of a synthetic resin, includes a cover body30, a supporting portion31provided to the cover body30and projecting toward the inside of the case1; and a step32and a cylindrical portion33provided to the cover body30at a side opposite with the supporting portion31.

The cover body30includes: a large-diameter portion301having a bottom surface3A facing the inside of the case1; and a small-diameter portion302integral with a surface of the large-diameter portion301opposite with the bottom surface3A.

The supporting portion31is an elongated member projecting from the bottom surface3A of the large-diameter portion301toward the inside of the case1. It should be noted that the bottom surface3A of the cover body30may be provided with a guide groove G so that the holder9can be attached to the cover body30without interference of the wiring or the like (not shown) connected to the terminals81(see imaginary lines inFIGS. 6 and 7).

The step32projects from an outer surface of the cover body30opposite with the bottom surface3A. The step32is in an oblong shape in a plan view and has operation holes32A arranged side by side (on right and left sides as shown inFIG. 4).

The left one of the operation holes32A is provided so that the operable portion72A of the electronic adjusting unit72for span adjustment can be operated with a tool such as a driver (not shown). The right one of the operation holes32A is provided so that the operable portion72A of the electronic adjusting unit72for zero adjustment can be operated with a tool such as a driver (not shown).

The operable portions72A are disposed right under the operation holes32A so that the operable portions72A can be easily operated with a tool such as a driver.

The cylindrical portion33is provided adjacent to the step32and has an inner circumferential surface defining a mount hole33A in which the cylindrical member80is to be mounted. The cylindrical portion33has an outer circumferential surface provided with a male thread.

With reference toFIGS. 6 to 9, description will be made on an arrangement for the circuit board7to be supported on the cover member3.

FIG. 6shows an overall arrangement for the circuit board7to be supported on the cover member3.FIG. 7shows the holder9to be attached to the cover member3.FIG. 8shows a relevant part of the supporting portion31.

As shown inFIGS. 4 to 7, the supporting portion31includes supporting portions disposed at two opposite positions on an outer periphery of the bottom surface3A of the large-diameter portion301.

The supporting portions31each include a base34and pair(s) of support projections35provided to an inner surface of the base34. The respective inner surfaces of the supporting portions31are opposed to each other in parallel.

The support projections35, which are configured to support the first substrate701and the second substrate702, include three support projections extending along a longitudinal direction of the base34(a projecting direction of the supporting portions). Specifically, the support projections35include a center support projection disposed at the center of the base34, a first side support projection disposed at a first edge of the base34and a second side support projection disposed at a second edge of the base34opposite with the first edge, the center support projection and the first side support projection being paired to support the first substrate701, the center support projection and the second side support projection being paired to support the second substrate702.

A surface of the center support projection35and a surface of the first side support projection35(i.e., a pair of first support surfaces351) respectively face peripheries of two opposite flat surfaces of the first substrate701, the first support surfaces351having edges connected by an inner surface of the base34(i.e., a second support surface342) that faces a side surface70A of the first substrate701.

Similarly, a surface of the center support projection35and a surface of the second side support projection35(i.e., another pair of first support surfaces351) respectively face peripheries of two opposite flat surfaces of the second substrate702, the first support surfaces351having edges connected by an inner surface of the base34(another second support surface342) that faces a side surface70A of the second substrate702.

In the exemplary embodiment, the pair of first support surfaces351and the second support surface342in combination define a support groove34A that supports the first substrate701.

A claw36is provided between the center support projection35and the first side support projection35to prevent detachment of the first substrate701. It should be noted that although it seems that only one of the pairs of supporting portions31is provided with the claw36in the figures, the other supporting portion31is also provided with another claw36having the same structure.

The claw36is provided to a distal end of the base34in a projecting manner.

It should be noted that a line connecting the respective centers of the opposite supporting portions31coplanar with the bottom surface3A is offset from an imaginary line passing through the circle center of the bottom surface3A. Further, an outer surface of the base34is in an arc along an inner circumferential surface of the case1, and is provided with a slope so that the base34is tapered from the bottom surface3A toward the distal end thereof. The second side support projection35for supporting the second substrate702is thus longitudinally shorter than the first support projection35for supporting the first substrate701, so that an end of the second substrate702is exposed. Therefore, the claw36is not provided between the center support projection35and the second side support projection35. It should be noted that the slope provided to the outer surface of the base34to taper the base34from the bottom surface3A toward the distal end thereof is necessary in molding each of the supporting portions31from a synthetic resin and, further, contributes to easy insertion of the cover body30into the case1.

The holder9will be described with reference toFIGS. 4 to 7 and 9.FIG. 9shows the holder9attached to the cover member3.

As shown inFIGS. 4 to 7 and 9, the holder9is a metal member for holding the circuit board7with a flat surface of the circuit board7being perpendicular to the bottom surface3A.

The holder9includes a flat portion91facing the bottom surface3A of the cover member3and an engagement piece92provided to the flat portion91to be engaged with the second substrate702.

The flat portion91includes a first plate91A and a second plate91B integrally provided to the first plate91A.

The first plate91A, which is to be held between the stepped portion13of the case1and the bottom surface3A of the cover member3, has an outline in conformity with an inner circumferential surface of the fitting ring12.

The first plate91A has an arc outer surface and a linear portion opposite with the outer surface, the linear portion being brought into contact with side surfaces of the supporting portions31. When the first plate91A is brought into contact with the side surfaces of the supporting portions31, the holder9is positioned relative to the cover member3(seeFIGS. 6 and 7).

The second plate91B is inserted between the bottom surface3A of the cover member3and the first substrate701and the second substrate702at a position between the pair of supporting portions31(seeFIG. 7).

The second plate91B includes two windows91C,91D and an arc end91E opposite with the first plate91A.

The window91C serves as a space for inserting the wiring or the like for electrically connecting the terminals81and the circuit board7. The window91D serves as a space for preventing the holder9from interfering with a tool such as a driver inserted through one of the operation holes32A to operate the operable portion72A.

As shown inFIG. 9, the end91E of the second plate91B, which is to be held between the stepped portion13of the case1and the bottom surface3A of the cover member3, has an outline in conformity with the inner circumferential surface of the fitting ring12.

The fitting ring12of the case1is crimped to fasten the cover body30and the flat portion91of the holder9to each other. In the exemplary embodiment, the fitting ring12is continuously crimped along the entire circumference thereof (i.e., full-circumference crimping), but may alternatively be crimped at predetermined spots (i.e., spot crimping). It should be noted that the respective outlines of the first plate91A and the end91E of the second plate91B may be, for instance, in a trapezoidal shape instead of being in an arc as long as the first plate91A and the end91E of the second plate91B are held between the stepped portion13of the case1and the bottom surface3A of the cover member3.

As shown inFIGS. 4 to 7, the engagement piece92includes a rising piece92A integral with the first plate91A and an engagement claw92B integral with the rising piece92A and engageable with an engagement hole702A provided to the second substrate702. The engagement hole702A and the engagement claw92B are fixed by soldering (not shown).

In the exemplary embodiment, the engagement hole702A includes two right and left engagement holes provided to the second substrate702at positions near the bottom surface3A of the cover member3(an upper end inFIGS. 5 and 6). The engagement piece92also includes two engagement pieces (two rising pieces92A) in accordance with the number of the engagement holes702A.

An arrangement of the cap member5will be described with reference toFIGS. 3 to 5 and 10 to 12.FIGS. 10 to 12show a detailed arrangement of the cap member5.

As shown inFIGS. 3 to 5 and 10 to 12, the cap member5includes: two cap bodies51removably attachable to the two operation holes32A provided to the step32; and a uniting portion52uniting the cap bodies51to each other. The uniting portion52is connected to a first end of an elastic linear loss-preventing member53made of a synthetic resin. A second end of the linear loss-preventing member53is engageable with the cover body30.

The cap member5has an outer wall that faces the cylindrical portion33. The outer wall is provided with a recess SA shaped in conformity with an outer circumferential shape of the cylindrical portion33.

In the exemplary embodiment, the two cap bodies51and the uniting portion52of the cap member5are integrally formed from a rubber or a synthetic resin.

The cap bodies51each include: an outer wall511having an inner circumferential surface engageable with an outer circumferential surface of the step32; an inner wall512having an outer circumferential surface engageable with an inner circumferential surface of the operation hole32A; and a top plate513connected to a base edge of the outer wall511and a base edge of the inner wall512.

The outer circumferential surface of the step32is provided with a plurality of circumferential lugs320. The outer wall511has an inner circumferential surface in contact with edges of the lugs320. When the edges of the lugs320are in contact with the inner circumferential surface of the outer wall511, waterproofness is improved. It should be noted that the inner circumferential surface of the outer wall511may be provided with a circumferential groove51A engageable with the lugs320in the exemplary embodiment (see imaginary lines inFIGS. 11 and 12).

The inner wall512is in pressure contact with the operation holes32A over a predetermined length.

The top plate513is provided with identification signs51S,51Z for identifying the operable portions72A. In the exemplary embodiment, the left one of the operation holes32A in the figures is provided for operating the operable portion72A of the electronic adjusting unit72for span adjustment, so that the a mark “S” is printed as the identification sign51S. The right one of the operation holes32A is provided for operating the operable portion72A of the electronic adjusting unit72for zero adjustment, so that a mark “Z” is printed as the identification sign51Z (seeFIGS. 3, 4 and 10). It should be noted that the identification signs51S,51Z are different marks in the exemplary embodiment, but may alternatively be, for instance, different letters and/or have different colors.

The uniting portion52includes a uniting plate521coplanar and integral with the top plate513and a uniting wall522coplanar and integral with the outer wall511.

The uniting plate521is connected to the first end of the linear loss-preventing member53.

The linear loss-preventing member53is an elastic string body made of a synthetic resin and the second end of the linear loss-preventing member53is inserted into a hole portion32B provided to the step32between the two operation holes32A.

The hole portion32B includes: a large-diameter part32B1provided to the cover body30and opened in the bottom surface3A; a small-diameter part32B2provided to the step32and opened in a flat surface of the step32; and a stepped portion32B3defined between the large-diameter part32B1and the small-diameter part32B2. The linear loss-preventing member53is engageable with the stepped portion32B3of the hole portion32B.

The linear loss-preventing member53has a length sufficient to avoid interference of the cap member5with a tool such as a driver inserted into one of the operation holes32A when the cap member5is removed and a retaining portion530is engaged with the stepped portion32B3of the hole portion32B. The retaining portion530is thus spaced from the hole portion32B when the cap member5is attached on the step32.

The retaining portion530includes a split portion531provided to the second end of the linear loss-preventing member53and an adhesive532provided to a gap between split ends of the split portion531. The adhesive532may be an instant adhesive, a molding compound or the like.

The adhesive532serves to keep a dimension between the split ends of the split portion531wider than an inner diameter of the small-diameter part32B2(seeFIGS. 11 and 12).

It should be noted that the shape of the split portion531may be changed as desired in the exemplary embodiment, and thus may be in a V-shape, U-shape or rectangular shape (in a cross section) as shown inFIGS. 11 and 12. Further, as shown inFIGS. 11 and 12, the second end of the linear loss-preventing member53may be split into two parts by providing one slit, into three parts by providing three slits, or into four parts by providing two intersecting slits.

Next, description will be made on a method of manufacturing the physical quantity measuring device according to the exemplary embodiment.

Detector Attaching Process

The detector6is, for instance, welded to the shaft21of the joint2and the first open end of the case1is, for instance, welded to the joint2.

Cover Member Assembling Process

The cylindrical member80of the signal transmitting member8is mounted in the cylindrical portion33of the cover member3, and the cap member5is attached to the cover member3.

In order to attach the cap member5to the cover member3, the linear loss-preventing member53is first inserted into the hole portion32B until the second end of the linear loss-preventing member53is exposed from the bottom-side open end of the hole portion32B of the cover member3. The uniting portion52and the linear loss-preventing member53of the cap member5are integrally formed in advance. It should be noted that the uniting portion52and the first end of the linear loss-preventing member53of the cap member5may alternatively be connected to each other with an adhesive or the like in the exemplary embodiment.

The retaining portion530is then provided on the second end of the linear loss-preventing member53.

In order to provide the retaining portion530, after or before the linear loss-preventing member53is inserted into the hole portion32B, a slit is provided to the second end of the linear loss-preventing member53. The slit ends of the second end of the linear loss-preventing member53are then separated to form the split portion531and the adhesive532is applied to the split portion531. When the adhesive532is cured, the split portion531is kept split. In this manner, the retaining portion530is provided on the second end of the linear loss-preventing member53.

In the cover member assembling process, the cap bodies51of the cap member5are attached to the two operation holes32A of the step32. In the above state, the retaining portion530is spaced from the hole portion32B (seeFIG. 1).

Process for Attaching Circuit Board in Case

Next, the substrate body70including the electronic circuit unit71and the electronic adjusting units72is attached to the cover member3. Specifically, the first substrate701and the second substrate702of the substrate body70are pushed into the cover body30along the support grooves34A defined by the support projections35of the cover member3. Before pushing the first substrate701, the claws36opposed to each other are pushed away from each other. When the first substrate701is pushed deepest into the cover body30, the claws36approach each other with the assistance of an elasticity of the supporting portions31to which the claws36are provided, so that the end of the first substrate701is held by the claws36.

When the first substrate701is held by the claws36, a gap is defined between the substrate body70and the bottom surface3A of the cover body30. The holder9is then inserted into the gap (seeFIG. 7) until the first plate91A is brought into contact with the side surfaces of the supporting portions31and the engagement pieces92are inserted into the engagement holes702A to engage the second substrate702. The engagement pieces92and the engagement holes702A are then soldered to each other.

The circuit board7thus held relative to the cover member3is then disposed inside the case1. In the exemplary embodiment, the cover member3, the circuit board7and the holder9are shaped in conformity with one another to be a unit.

It should be noted that the detector6and the circuit board7as well as the circuit board7and the signal transmitting member8are connected through a wiring at an appropriate timing, for instance, prior to the detector attaching process.

Bonding Process

The cover body30of the cover member3is bonded to the second open end of the case1. Specifically, the cover member3with the circuit board7supported thereon is fitted in the fitting ring12of the case1. The holder9is thus held between the stepped portion13of the case1and the cover body30, so that the circuit board7engaged with the holder9is immobilized in the case1. Simultaneously, the holder9is electrically connected to the case1.

Subsequently, an edge of the fitting ring12is crimped to fix the cover body30and the flat portion91of the holder9to each other.

Immediately after the thus-manufactured physical quantity measuring device is attached to the mount or after a predetermined operation of the thus-manufactured physical quantity measuring device is performed, the electronic adjusting unit(s)72may be adjusted.

In order to adjust the electronic adjusting unit(s)72, the cap member5is held and pulled. The cap bodies51are thus removed from the operation holes32A so that the operation holes32A are uncovered. Even when the cap member5is pulled with a large force, the linear loss-preventing member53is prevented from being completely pulled out with the assistance of the retaining portion530provided on the second end of the linear loss-preventing member53, the retaining portion530being engaged with the stepped portion32B3of the hole portion32B of the cover body30. It should be noted that the linear loss-preventing member53has the predetermined length, so that the electronic adjusting unit(s)72can be adjusted without interference of the cap bodies51.

After the two operation holes32A are uncovered, a tool such as a driver is inserted into one of the operation hole32A corresponding to one of the electronic adjusting units72to be adjusted, and the operable portion72A is operated with the tool.

The one of the electronic adjusting units72to be adjusted can be identified with reference to the identification signs51S,51Z printed on the cap bodies51.

With the uniting portion52uniting one of the cap bodies51to the other cap body51, both cap bodies51are not separated from each other irrespective of whether or not the cap bodies51are removed.

After the completion of adjustment of the electronic adjusting unit(s)72, the uncovered operation holes32A are covered by the cap bodies51.

The exemplary embodiment as described above provides the following advantageous effects.

(1) The plate-shaped circuit board7, which receives a detection signal from the detector6, is housed in the case1and is held by the holder9with the flat substrate surface thereof intersecting with the bottom surface3A of the cover member3. The holder9is attached to the cover member3. The cover member3includes the cover body30, the elongated supporting portions31projecting from the bottom surface3A of the cover body30into the case1. The supporting portions31each include the pair of support projections35that longitudinally support one of the opposite lateral side surfaces70A of the circuit board7. The holder9includes the engagement pieces92engageable with the second substrate702of the circuit board7. With the above arrangement, it is not necessary to bond the circuit board7to a member of the detector, so that an assembly process for the physical quantity measuring device can be simplified. Further, since each of the side surfaces70A of the circuit board7is longitudinally supported by the support projection35, the circuit board7can be accurately positioned to the bottom surface3A. Further, since the holder9is attached to the cover member3and the circuit board7is engaged with the holder9, the circuit board7is immobilized to the cover member3and thus reliably held relative to the cover member3.
(2) The supporting portions31each include the claw36disposed between the support projections35to prevent detachment of the circuit board7from the bottom surface3A. The holder9includes the flat portion91facing the bottom surface3A of the cover member3. With the above arrangement, the claw36serves to prevent the circuit board7from falling off the support projections35, so that displacement of the circuit board7relative to the cover member3is restrained and thus the circuit board7is further reliably held relative to the cover member3.
(3) A peripheral portion of the holder9is held between the cover body30and the case1, thereby easily and reliably attaching the holder9to the cover member3.
(4) The case1is crimped to fix the cover body30to the flat portion91of the holder9, thereby stably supporting the circuit board7to the cover member3and, further, simplifying the assembly process of the device.
(5) The case1and the holder9are made of metal and the cover member3is made of a synthetic resin, so that the circuit board7can be easily grounded.
(6) The substrate body70includes the two first substrate701and second substrate702arranged in parallel, so that electronic components required for pressure detection can be arranged not only on the first substrate701but also on the second substrate702. Therefore, as compared with the case where the electronic components are arranged in a single substrate, a length of the physical quantity measuring device defined in an axial direction of the case1can be reduced.
(7) The engagement pieces92each include the engagement claw92B engageable with one of the engagement holes702A of the second substrate702. The second substrate702can thus be easily supported by the holder9. Further, displacement of the circuit board7in an in-plane direction of the flat portion91of the holder9can be prevented.
(8) Since the engagement holes702A are provided to the second substrate702at positions adjacent to the bottom surface3A, the engagement pieces92can be shortened, which results in reduction in the possibility of breakage or the like of the engagement piece92.
(9) The pair of support projections35have surfaces facing each other (i.e., the pair of first support surfaces351), the first support surfaces351facing the peripheries of the flat surfaces of the first substrate701or the second substrate702. The peripheries of the first support surfaces351are connected by a surface (i.e., the second support surface342) that faces one of the side surfaces70A of the first substrate701or the second substrate702. The above two support surfaces including the first support surfaces351and the second support surface342define the U-shaped support groove34A for supporting the first substrate701or the second substrate702. With the U-shaped support groove34A, the first substrate701or the second substrate702is reliably supported in three directions.
(10) The cover member3, the circuit board7and the holder9are shaped in conformity with one another to be a unit, which results in a reduction in the number of components and thus in a reduction in production costs.
(11) The circuit board7including the electronic circuit unit71and the electronic adjusting units72is disposed in the case1. The signal transmitting member8connected to the circuit board7is mounted in the mount hole33A of the cover member3. The cover member3is provided with the operation holes32A corresponding to the plurality of operable portions72A of the electronic adjusting units72. The cap member5is attached to the cover member3to cover the operation holes32A. The operation holes32A for adjusting the electronic adjusting units72are easily covered/uncovered by the cap member5with the simple arrangement including the plurality of cap bodies51and the uniting portion52uniting the cap bodies51. The operation holes32A are independent of the mount hole33A where the signal transmitting member8is mounted, so that the electronic adjusting units72can be adjusted irrespective of whether or not the signal transmitting member8mounted in the mount hole33A is connected to any other connection member.
(12) The linear loss-preventing member53with elasticity has the first end, for instance, integral with or connected to the uniting portion52and the second end engageable with the stepped portion32B3of the hole portion32B of the cover member3. With the above arrangement, the cap member5is undetachable from the cover member3, so that the operation holes32A can be prevented from being inadvertently left uncovered by the cap member5. Further, the linear loss-preventing member53exhibits elasticity and the cap member5can be laid at a position remote from the operation holes32A during adjustment of the electronic adjusting unit(s)72, thereby facilitating the adjustment of the electronic adjusting unit(s)72.
(13) The step32projecting from the cover body30is provided with the operation holes32A. Further, the cap bodies51have the inner walls512engageable with the inner circumferential surfaces of the operation holes32A and the outer walls511having the inner circumferential surfaces engageable with an outer circumferential surface of the step32. With the above arrangement, water is reliably prevented from entering the case1through the operation holes32A.
(14) The linear loss-preventing member53, which is inserted into the hole portion32B provided to the step32at a position between the operation holes32A arranged side by side, has the first end, for instance, integral with or connected to the uniting plate521disposed at the center of the cap member5. A space between the operation holes32A can thus be efficiently used as a space for inserting the linear loss-preventing member53. Consequently, the device size can be reduced.
(15) The linear loss-preventing member53has the second end provided with the retaining portion530, so that the cap bodies51are reliably prevented from coming out of the cover member3.
(16) The retaining portion530includes the split portion531formed by splitting the second end of the linear loss-preventing member53and the adhesive532provided to a gap between split ends of the split portion531. The retaining portion530can thus be easily provided.
(17) The cylindrical portion33in which the signal transmitting member8is mounted is disposed adjacent to the step32, and the cap member5is provided with the recess SA shaped in conformity with the outer circumferential shape of the cylindrical portion33. With the above arrangement, as long as the recess SA is positioned in conformity with the outer circumferential shape of the cylindrical portion33, the cap member5can be attached to the operation holes32A without being laterally inverted.
(18) The top plate513of the cap member5is provided with the identification signs51S,51Z for identifying the operable portions72A, so that when the cap member5is removed to operate one of the operable portions72A, wrong one of the operable portions72A can be kept from being operated.
(19) Prior to attaching the cap member5to the cover member3, the linear loss-preventing member53is inserted until the second end of the linear loss-preventing member53is exposed from the bottom-side open end of the hole portion32B, and then the retaining portion530is provided on the second end of the linear loss-preventing member53. The physical quantity measuring device can thus be efficiently manufactured.

Incidentally, it should be understood that the scope of the invention is not limited to the above exemplary embodiment, but includes modifications and improvements compatible with the invention.

For instance, in the above exemplary embodiment, the substrate body70includes the first substrate701and the second substrate702, but may alternatively include three substrates or a single substrate as shown inFIGS. 13 to 15.

As shown inFIGS. 13 to 15, two support projections35are provided along the longitudinal direction of the base34to support the single substrate body70.

According to the invention, the engagement holes702A may be provided to the second substrate702at the farthest positions from the bottom surface3A (near the lower edge of the substrate body70). In this case, the rising pieces92A of the engagement pieces92are replaced by elongated rising pieces.

The elongated rising pieces may have inner surfaces that face each other at a predetermined distance equal to the width of the substrate body70and are each provided with a guide groove for guiding the side surface70A of the substrate body70without departing from the scope of the invention. In this case, the pair of support projections35may be shortened in a direction perpendicular to a mutually facing direction (i.e., shortened along a thickness direction of the substrate body70) so that the support projections35face a rear surface of the substrate body70and support the periphery of the substrate body70in combination with the elongated rising pieces. Ends of the support projections35may each be provided with a claw for supporting the lower edge of the substrate body70.

In the exemplary embodiment, the case1is crimped to directly attach the holder9to the cover body30, but the holder9may be indirectly attached to the cover member3with an intervening member such as an adhesive between the cover body30and the holder9according to the invention. According to the invention, an arrangement different from the above may be employed to directly attach the holder9to the cover body30. For instance, the holder9may be fastened to the cover member30fitted on the case1, or may be fastened to the cover body30with a fastener such as a bolt.

Further, the above arrangement of the cap member5described in the exemplary embodiment is not requisite for the invention. For instance, two cap members with the same shape may be independently attached to the operation holes32A without being connected using a string.

The operation holes32A for operating the operable portions72A are provided to the cover member30, but the operation holes may be provided to a circumferential surface of the case1according to the invention.

Further, according to the invention, the supporting portions31may include no claw36and the holder9may include no flat portion91.

In the above exemplary embodiment, the description is made on the physical quantity measuring device configured to measure a pressure, but the invention is applicable to, for instance, a differential pressure sensor and a temperature sensor in addition to the physical quantity measuring device.