JPH1117366A - Holder for fixing substrate of meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a printed board without backlash by providing a projecting section which abuts against the inner peripheral surface of an enclosure on the external surface of a piece section and, in addition, to reduce the size and weight of a meter itself by simplifying a fixing structure. SOLUTION: In the case of incorporating printed boards 4 in a case 1, the boards 4 are first held in a holder 10 before the holder 10 is fitted into the case 1, and then, the holder 10 is fitted into the case 1 while the holder 10 holds the boards 4. When the holder 10 is fitted into the case 1, the projecting section 12A of a piece section 12 abuts against the inner peripheral surface of the case 1 and is elastically deformed inward. Consequently, the holder 10 is fitted into and held in the case 1 without play and, at the same time, the printed board holding force of the holder 10 is increased, resulting in the firm fixation of the printed boards 4 in the case 1. When a play starts to occur between the case 1 and printed boards 4, the play is absorbed by the elasticity of the piece section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holder for an instrument, which is fitted in a casing of the instrument and holds a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, for example, a differential pressure
A printed circuit board incorporated in a field-type device (field device) such as a pressure transmitter is fixed inside the casing of the instrument by screwing or soldering. In the case of screwing, a female screw part is formed at a fixed position on the housing side, a hole is made in the printed circuit board side, and a screw passing through the hole is screwed to the female screw part on the housing side, so that the printed circuit board is Fixed to. On the other hand, in the case of soldering, the printed circuit board is fixed to the housing by soldering the terminals positioned on the case side to the printed circuit board.

[0003]

Conventionally, the printed circuit board is fixed to the instrument housing as described above.
When the instrument itself is used in a poor temperature environment, there are the following problems. That is, when the components of the instrument including the housing and the printed circuit board expand and contract due to changes in the temperature environment, a difference occurs in the thermal expansion and thermal contraction of those components, and the screws for screwing the printed circuit board are loosened. In addition, the soldered portion for fixing the printed circuit board may be peeled off, and the printed circuit board may be loose. If a connector is attached to the printed circuit board, the connector may come off due to rattling on the printed circuit board,
There was also a risk of poor contact. In addition, there is a problem to be solved in that the screwing and soldering work for fixing the printed circuit board requires man-hours, and the number of components increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can fix a printed circuit board securely and easily without rattling. It is an object of the present invention to provide an instrument substrate fixing holder that can suppress the occurrence of sticking and can reduce the size and weight of the instrument itself by simplifying the structure for fixing the printed circuit board.

[0005]

According to a first aspect of the present invention, there is provided an instrument substrate fixing holder, comprising: an elastic piece provided at a portion facing an inner peripheral surface of a housing of the instrument; A projection is provided on an outer surface and abuts on an inner peripheral surface of the housing, and a holding portion provided on an inner surface of the piece and holding a printed circuit board is provided.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 and FIG. 2 are views for explaining Embodiment 1 of the present invention. This example is an application example as a substrate fixing holder in a differential pressure / pressure transmitter.
In FIG. 1, reference numeral 1 denotes a cylindrical case having a bottom, and 2 denotes a cap which is screwed to an opening of the case 1.
A housing 3 of the pressure transmitter is configured. Case 1
An unillustrated signal line or power supply line outlet 1A is formed. Reference numeral 10 denotes a substrate fixing holder made of a synthetic resin or the like, which is formed in a bottomed cylindrical shape that can be fitted into the case 1. A plurality of elastic pieces 12 are formed on the peripheral wall 11 of the holder 10 at equal intervals along the circumferential direction. As shown in FIG. 2, the lower portion of the piece portion 12 is a base end,
The upper part is a free end, and is elastically deformable in the radial direction. A protruding portion 12 </ b> A is formed on the upper surface of the outer surface of the piece 12 to contact the inner peripheral surface of the case 1.
A nail 12B for positioning the printed circuit board 4 is formed on the inner surface of. The printed circuit board 4 has a differential pressure
An electric component (not shown) for constituting an electric circuit of the pressure transmitter is mounted. In the case of this example, two claws 12B are formed vertically so that the two printed circuit boards 4 are positioned vertically. The nail 12B is a printed circuit board 4
The upper surface of the printed circuit board 4 is regulated by facing the upper surface of the printed circuit board 4, and the printed circuit board 4 is held between the lower surface of the printed circuit board 4 and the stopper 13 facing the lower surface. Therefore, the claws 12B constitute a holding portion for holding the printed circuit board 4. The stopper 13 may be formed on the inner surface of the piece 12 or may be formed on the inner surface of the peripheral wall 11.

Next, the operation will be described. When assembling the printed circuit board 4, first, as shown in FIG. 2, the printed circuit board 4 is held inside the holder 10 before being fitted into the case 1. At this time, the printed circuit board 4 is fitted into the holder 10 from above, and when the printed circuit board 4 passes through the position facing the pawl 12B, the piece 12 temporarily hits the inclined surface of the upper part of the pawl 12B. The printed circuit board 4 is elastically deformed outward, and the printed circuit board 4 is held by the subsequent elastic return of the piece 12 to the inside.

Thereafter, the holder 10 holding the printed circuit board 4 is fitted into the case 1 and attached. When the holder 10 is fitted, the projection 12A of the piece 12 comes into contact with the inner peripheral surface of the case 1, and the piece 12 is elastically deformed inward as shown in FIG. As a result, the holder 10 is fitted and held in the case 1 without play, and the holding force of the printed board 4 in the holder 10 is increased, so that the printed board 4 is securely fixed in the case 1. Further, in the use environment of the differential pressure / pressure transmitter in which the printed circuit board 4 is incorporated as described above, there is a backlash between the case 1 and the printed circuit board 4 due to a difference in thermal expansion or the like. If it is to be generated, the occurrence of the backlash is absorbed by the elasticity of the piece 12 of the holder 10.

As described above, according to the first embodiment, the piece 12 of the holder 10 prevents the printed circuit board 4 from rattling even under a poor use environment of the differential pressure / pressure transmitter. Thus, it can be securely fixed inside the case 1. Further, the printed circuit board 4 can be easily fixed in the case 1 by fitting the printed circuit board 4 into the holder 10 and fitting the holder 10 into the case 1. Moreover, since the printed circuit board 4 can be fixed with a simple configuration having only the holder 10, the differential pressure / pressure transmitter itself can be reduced in size and weight.

Embodiment 2 FIG. 3 is a diagram for explaining Embodiment 2 of the present invention. In this case,
The protrusion 12 is located at an intermediate position between the upper and lower claws 12B of the holder 12.
A is formed. According to the second embodiment, the printed circuit board 4 can be securely fixed by the upper and lower claws 12B by sufficiently deforming the piece 12 inward even if the distance between the upper and lower printed circuit boards 4 is large. .

Embodiment 3 FIG. 4 is a diagram for explaining Embodiment 3 of the present invention. In this case,
A claw 12C and a stopper 14 for holding the terminal plate 5 are formed together with a claw 12B and a stopper 13 for holding the two printed circuit boards 4. The stoppers 13 and 14 are formed in a claw shape, and are formed on the piece portion 12 similarly to the claws 12B and 12C. Also, the protrusion 12A
Is bent outward from the upper end of the piece 12, and a groove 1 </ b> B into which the protrusion 12 </ b> A elastically fits is formed on the inner peripheral surface of the case 1. Reference numeral 6 denotes a terminal attached to the terminal plate 5, and 7 denotes a ground wire connected to a ground terminal of the terminal plate 5. The ground wire 7 is formed of a spring material, and is pulled out from the notch 12D of the holder 10. When the case 1 is conductive, grounding can be achieved by bringing the ground wire 7 into contact with the case 1. According to the third embodiment, the protrusion 12
Due to the engagement between the groove A and the groove 1B, the holder 10 can be easily fixed simply by fitting the holder 10 to a fixed position in the case 1.

Embodiment 4 FIG. 5 is a cross-sectional view for describing Embodiment 4 of the present invention. In the case of this embodiment, a rotation preventing projection 1C is formed on the inner peripheral surface of the case 1, and a hole 10A is formed on the outer peripheral surface of the holder 10. Then, the holder 10 is prevented from rotating due to the engagement between the projection 1C and the hole 10A. Projection 1C
A plurality of pairs of holes 10A may be formed. Embodiment 4
According to this, by the fitting of the projection 1C and the hole 10A, the holder 10 can be prevented from rotating only by fitting the holder 10 to a fixed position in the case 1.

[0013]

As described above, according to the first aspect of the present invention, an elastic piece is provided at the portion of the holder facing the inner peripheral surface of the instrument housing, and the protrusion is provided on the outer surface of the piece. In addition to the provision, the holding portion of the printed circuit board is provided on the inner surface of one of the portions, so when the holder is fitted inside the housing, the protrusion on the side of the holder and the inner peripheral surface of the housing are brought into contact, By elastically deforming the one part, the printed circuit board can be securely and easily fixed without rattling, and the occurrence of rattling of the printed circuit board can be suppressed even in an inferior use environment. By simplifying the fixing structure, the instrument itself can be reduced in size and weight.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of an instrument provided with a holder according to Embodiment 1 of the present invention.

FIG. 2 is a perspective view of a main part of the holder of FIG.

FIG. 3 is a longitudinal sectional view of a main part of an instrument provided with a holder according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional view of an instrument provided with a holder according to Embodiment 3 of the present invention.

FIG. 5 is a cross-sectional view of an instrument provided with a holder according to Embodiment 4 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Cap 3 Housing 4 Printed circuit board 5 Terminal board 10 Holder 11 Peripheral wall part 12 Piece 12A Projection part 12B Claw 13 Stopper

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noto Omura 2-12-19 Shibuya, Shibuya-ku, Tokyo Inside Yamatake Ha Newel Co., Ltd. (72) Shun-ichiro Awa 2-12-19 Shibuya Shibuya-shi, Tokyo Inside Yamatake Newell Co., Ltd.

Claims (1)

[Claims] 1. A substrate fixing holder for an instrument, which is fitted into an instrument housing and holds a printed circuit board, wherein an elastic piece provided at a portion facing an inner peripheral surface of said instrument, A board for an instrument, comprising: a projection provided on an outer surface of a piece and abutting against an inner peripheral surface of the housing; and a holding section provided on an inner surface of the piece and holding the printed board. Holder for fixing.