Circuit board fixing structure

Abstract

To provide a circuit board fixing structure capable of narrowing a space between a housing and a circuit board without reducing a boss.SOLUTION: A circuit board 2 comprises a boss insertion hole 21 into which a boss 3 provided to a housing 1 is inserted, and an engagement step part 31 that includes a pressing member 4 for fixing the circuit board 2 so as to be covered to the boss 3, engages the circuit board 2 into which the boss 3 is inserted to a base part of the boss 3, and positions the circuit board 2 in the housing 1. The pressing member 4 is formed by including: a cover setting part 4a that covers the boss 3 projected from the circuit board 2 into which the boss 3 is inserted; and an upper surface 43 that is arranged onto a top surface of the boss 3, and includes a screw insertion hole 41 inserting a screw to be screwed into the boss 3. In the pressing member 4 covered and provided to the boss 3, when the screw 5 is screwed into the boss 3 via the screw insertion hole 41, a lower end of the pressing member 4 presses the circuit board 2 to be tightly adhered to the engagement step part 31, and the circuit board 2 is fixed to the housing 1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a board fixing structure for fixing a circuit board inside a housing. [Background technology]

[0002] When assembling a circuit board inside a housing using screws, it is common to form a boss on the housing for screwing the screw into, and to provide a hole in the circuit board for inserting the screw, and then screw the screw into the boss through the circuit board to secure it in place (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-197120 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration where a circuit board is fixed with a screw, the screw hole in the case needs to be long enough, and as a result, the boss needs to be tall enough, so a relatively long fixing boss is placed inside the case, and a relatively large space is created between the attached circuit board and the case. When attempting to make the housing thinner or more compact, the presence of this long boss makes it impossible to narrow the space between the housing and the circuit board, and this has been an obstacle to making the housing thinner and more compact.

[0005] In view of the above problems, the present invention has an object to provide a circuit board fixing structure that can narrow the space between the housing and the circuit board without shortening the boss. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a circuit board fixing structure in which a boss having a screw insertion hole is provided on a housing, and a screw is screwed into the boss with the circuit board engaged therewith to fix the circuit board within the housing, the circuit board having a boss insertion hole through which the boss is inserted, and a pressing member is provided over the boss and for inserting the boss into the housing to fix the circuit board placed within the housing, the base of the boss which rises from the housing is provided with a locking step portion for locking the circuit board inserted into the boss and positioning the circuit board within the housing, the pressing member has a covering portion which covers the boss protruding from the circuit board placed within the housing, and a top surface which is provided on the top surface of the boss and has a screw insertion hole through which a screw that screws into the boss is inserted, and when a screw is screwed into the boss via the screw insertion hole, the lower end of the pressing member covering the boss presses the circuit board to make it adhere to the locking step portion, and the circuit board is fixed to the housing. With this configuration, the circuit board is locked to the locking step formed on the base of the boss, not the tip, so even if the gap between the circuit board and the case is small, the boss can maintain a long state in which it can hold the screw in. Meanwhile, the circuit board can be reliably fixed because it is pressed against the case by the pressing member.

[0007] Another aspect of the present invention is characterized in that, in the above configuration, the pressing member has an extended boss portion of the same dimensions as the boss on the upper part of the covering portion, the extended boss portion is formed with a smaller diameter than the covering portion and has a step portion formed around the upper part of the covering portion, is continuous with the boss housed in the covering portion, is formed in a cylindrical shape and is formed so that a screw can be screwed into the boss via the extended boss portion, and by covering the boss protruding from the circuit board assembled to the housing with a pressing member having an extended boss portion, it is possible to add and assemble a circuit board using the extended boss portion and the step portion. According to this configuration, a plurality of circuit boards can be attached to the housing by simply stacking the pressing members, and the circuit boards can be fixed with a simple configuration.

[0008] Another aspect of the present invention is characterized in that, in the above-mentioned configuration, the pressing member has a ring wall around the screw insertion hole, the ring wall being higher than the head of the inserted screw. With this configuration, the head of the screw is surrounded by the ring wall and does not protrude upward, making it easier to route the wires. Also, because the head of the screw enters the ring wall, it is possible to recognize when the screw has been fully tightened, and it is possible to prevent the screw from being fully tightened.

[0009] Another aspect of the present invention is characterized in that, in the above configuration, the screw insertion hole of the pressing member is formed with a recess shaped to match the shape of the head of the screw to be inserted, and the head of the screw that has been inserted and tightened is accommodated in the recess. With this configuration, the head of the screw is housed in the recess, eliminating any upward protrusions and making it easier to route the wires. In addition, the head of the screw fits into the recess, making it possible to check the state of the screw tightening. Effect of the Invention

[0010] According to the present invention, the circuit board is locked to the locking step formed at the base of the boss, not at the tip of the boss, so even if the gap between the circuit board and the case is made small, the boss can maintain a long state in which it can hold the screw in. Meanwhile, the circuit board can be reliably fixed because it is pressed against the case by the pressing member. [Brief description of the drawings]

[0011] [Figure 1] 1A and 1B show a first embodiment of a circuit board fixing structure according to the present invention, in which (a) is a partial plan view of a housing, and (b) is a perspective view of the portion shown in (a). [Diagram 2] FIG. 2 is an explanatory cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 11 is a perspective view showing a second embodiment of the circuit board fixing structure. [Figure 4] 2. FIG. 4 is an explanatory cross-sectional view of FIG. 3 corresponding to the cross-section of FIG. [Diagram 5] FIG. 11 is a perspective view showing a third embodiment of the circuit board fixing structure. [Figure 6] 6 is an explanatory cross-sectional view of FIG. 5 corresponding to the cross section of FIG. 2. [Figure 7] FIG. 11 is a perspective view showing a fourth embodiment of the circuit board fixing structure. [Figure 8] 8 is an explanatory cross-sectional view of FIG. 7 corresponding to the cross section of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Figures 1 and 2 show a first embodiment of a circuit board fixing structure according to the present invention, with Figure 1(a) being a partial plan view of a housing, Figure 1(b) being a perspective view of the portion of Figure 1(a), and Figure 2 being an explanatory cross-sectional view taken along line AA. In the figures, 1 is a housing to which a circuit board 2 is attached, 3 is a boss provided on the housing 1 for fixing the circuit board 2 with a screw 5, and 4 is a pressing member for fixing the circuit board 2.

[0013] Bosses 3 for fixing the circuit board 2 are formed at appropriate positions in the board accommodating portion E provided in the housing 1. Locking steps 31 for locking and positioning the circuit board 2 are formed at the bases of the bosses 3 that rise from the housing 1. The height of the locking steps 31 of each boss 3 is determined so that the fixing portion of the circuit board 2 is flat even if the board accommodating portion E of the housing 1 is not flat. D shown in FIG. 2 indicates the gap thus formed between the housing 1 and the circuit board 2 placed on the locking steps 31. The boss 3 is formed in a cylindrical shape with a constant diameter rising from the locking step 31, and a screw hole 3a into which a screw 5 is screwed is formed on the central axis M of the boss 3.

[0014] On the other hand, the circuit board 2 is provided with boss insertion holes 21 through which the bosses 3 are inserted. The boss insertion holes 21 are provided in accordance with the positions of the individual bosses 3.

[0015] The pressing member 4 is a member that brings the circuit board 2 into close contact with the locking step portion 31, and is formed in a lid shape that covers the boss 3 protruding from the circuit board 2. The pressing member 4 has a covering portion 4a that covers the boss 3 and is provided with an accommodating recess 42 that accommodates the portion of the boss 3 that protrudes from the circuit board 2, and a top surface 43 that is disposed on the top surface 32 of the boss 3 is formed with a screw insertion hole 41 for screwing a screw 5 into the boss 3.

[0016] The accommodating recess 42 is formed slightly shallower than the length of the boss 3. More specifically, it is formed shallower by the thickness of the circuit board 2 so that the lower end of the pressing member 4 covering the boss 3 abuts against the circuit board 2 arranged on the locking step 31. As a result, the pressing member 4 in contact with the circuit board 2 presses the circuit board 2 by screwing the screw 5 into the boss 3 and tightening it, so that the circuit board 2 is pressed against the locking step portion 31 .

[0017] In this way, the circuit board 2 is locked to the locking step 31 formed at the base of the boss 3, not at the tip thereof, so even if the gap D between the circuit board 2 and the housing 1 is made small, the boss 3 can maintain a long state in which the screw 5 is screwed in and held. Meanwhile, the circuit board 2 is fixed to the housing 1 by being pressed against it by the pressing member 4, so that it can be reliably fixed.

[0018] Next, modified examples (second to fourth embodiments) of the circuit board fixing structure will be described. In all of the modified examples, the shape of the pressing member 4 is different, but the shapes of the boss 3 and the like are the same, so the pressing member 4 will be mainly described. 3 and 4 show the second embodiment. In the pressing member 4 of the second embodiment, the covering portion 4a is extended upward, and a ring-shaped extension piece (ring wall) 44 is provided around the screw insertion hole 41. The extension piece 44 is formed higher than the head 51 of the screw 5, and is formed so that the head 51 of the screw 5 that is screwed into the boss 3 to fix the pressing member 4 is buried and hidden in the extension piece 44.

[0019] In this way, the head 51 of the screw 5 is hidden by the extension piece 44 formed on the pressing member 4, so that the electric wires arranged inside the housing 1 do not get caught on the head 51 of the screw 5, and the electric wires can be easily routed. In addition, since the head 51 of the screw 5 fits inside the extension piece 44, it is possible to recognize the state in which the screw has been tightened completely, and it is possible to prevent the screw from being tightened insufficiently.

[0020] 5 and 6 show a third embodiment of the circuit board fixing structure. In this third embodiment, in addition to the pressing member 4, the shape of the screw 5 used is different from the above embodiments. The screw 5 is a countersunk head screw 5a with an inverted cone-shaped head and a flat top surface. The pressing member 4 has a conical recess 45 formed in the upper surface 43 to match the shape of the head of the countersunk head screw 5a. Due to this recess 45, the head 51 of the countersunk head screw 5a screwed into the boss 3 is housed in the recess 45, and there is no portion protruding from the pressing member 4. In addition, a radius is provided around the periphery of the upper surface 43 to eliminate corners, making it difficult for electric wires, etc., to get caught.

[0021] In this way, since the head of the screw 5 is housed in the recess 45, it is possible to eliminate the upward protrusion of the screw 5, making it easier to route the electric wire. In addition, since the head of the screw 5 fits into the recess 45, the state of the screw tightening can be checked, and it is possible to prevent the screw from being tightened insufficiently.

[0022] 7 and 8 show a fourth embodiment of the circuit board fixing structure. In this fourth embodiment, the pressing member 4 has the function of a boss 3 for locking the circuit board 2. The pressing member 4 is formed in two stages, consisting of a lower covering portion 4a that covers the boss 3, and an upper extended boss portion 4b that extends from the covering portion 4a with a reduced diameter. The screw insertion hole 41 formed in the pressing member 4 is formed to continue to the extended boss portion 4b, and is formed on the central axis M of the boss 3. The covering portion 4a has the same shape as the pressing member 4 shown in Fig. 1, and is provided with the extended boss portion 4b thereon.

[0023] The extended boss portion 4b is formed to have the same diameter and length (height) as the boss 3, and a step portion 46 is formed at the boundary between the covering portion 4a and the extended boss portion 4b. This step 46 has the same function as the locking step 31 formed at the base of the boss 3, and locks the circuit board 2 with the extended boss portion 4b inserted into the boss insertion hole 21. As a result, by connecting a plurality of pressing members 4, a plurality of circuit boards 2 having the same shape can be attached to the board accommodating portion E of the housing 1.

[0024] In this way, multiple circuit boards 2 can be attached to the housing by simply stacking the pressing members 4, and can be fixed collectively with one screw 5, allowing the circuit boards 2 to be fixed with a simple structure. The length of the screw 5 used can be changed according to the number of pressing members 4 to be stacked.

[0025] In the second embodiment shown in Figures 3 and 4, the end of the extension piece 44 is formed in a rectangular shape and has corners, but it may be rounded to eliminate the corners, as in the third embodiment shown in Figures 5 and 6. [Explanation of symbols]

[0026] DESCRIPTION OF SYMBOLS 1...housing, 2...circuit board, 3...boss, 3a...screw hole, 4...pressure member, 4a...covering portion, 4b...extended boss portion, 5...screw, 21...boss insertion hole, 31...locking step portion, 32...top surface, 41...screw insertion hole, 42...accommodating recess, 43...upper surface, 44...extension piece (ring wall), 45...recess, 51...head portion.

Claims

1. A circuit board fixing structure, comprising: a housing provided with a boss having a screw insertion hole; a circuit board engaged with the boss; and a screw being inserted into the boss to fix the circuit board in the housing, The circuit board includes a boss insertion hole through which the boss is inserted, a pressing member provided over the boss for inserting the boss into the housing to fix the circuit board therein; A locking step is provided at a base portion of the boss, which is a rising portion from the housing, for locking the circuit board inserted through the boss and positioning the circuit board within the housing; the pressing member includes a covering portion that covers the boss protruding from the circuit board disposed within the housing, and a top surface that is disposed on a top surface of the boss and has a screw insertion hole through which a screw that is to be screwed into the boss is inserted, a pressing member provided over the boss, the lower end of which presses the circuit board against the locking step when a screw is screwed into the boss through the screw insertion hole, and the circuit board is fixed to the housing.

2. the pressing member has an extended boss portion on an upper portion of the covering portion, the extended boss portion having the same dimensions as the boss; the extended boss portion is formed with a smaller diameter than the covering portion, a step portion is provided around the upper portion of the covering portion, and the extended boss portion is formed in a cylindrical shape so that the screw can be screwed into the boss via the extended boss portion; The pressing member having the extended boss portion is provided to cover the boss protruding from the circuit board assembled to the housing, 2. The circuit board fixing structure according to claim 1, wherein the circuit board can be added and assembled by using the extended boss portion and the step portion.

3. 2. The circuit board fixing structure according to claim 1, wherein said pressing member has a ring wall around said screw insertion hole, said ring wall being higher than the head of the inserted screw.

4. 2. The circuit board fixing structure according to claim 1, wherein the screw insertion hole of the pressing member has a recess formed to match the shape of the head of the screw to be inserted, and the head of the screw that has been inserted and tightened is accommodated in the recess.

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