JP7619243B2 - Snap-fit structure and housing - Google Patents

Description

This disclosure relates to technology for a snap-fit structure that can be used, for example, in a housing that houses an electronic control device for a vehicle.

2. Description of the Related Art Conventionally, a housing in which a case and a cover are integrally combined has been known as a container for housing an electronic control device.
A snap-fit structure is also known as a structure for joining a case and a cover, in which a convex portion is provided on one member (e.g., the case) and a concave portion is provided on the other member (e.g., the cover), and the elasticity of the material is utilized to engage the convex portion with the concave portion, thereby joining the one member and the other member together.

For example, the following Patent Document 1 discloses a snap-fit structure for a housing using a metal cantilever with an opening and a resin case into which the cantilever is fitted, in which the side of the case is provided with a protrusion that fits into the opening of the cantilever and an L-shaped guide that guides both the left and right sides of the cantilever.

JP 2002-134963 A

However, as a result of detailed investigation by the inventors, the following problems were found in the conventional techniques.
For example, in a snap-fit structure in which the case and the cantilever that fits into the case are made of resin, first, as shown in Figures 14A and 14B, the left and right sides of the cantilever (P1) of the cover are inserted into the L-shaped guides (P3) on the left and right of the case (P2), and the cantilever is pushed in the direction of the arrow Z.

Next, as shown in Figure 14C, when the cantilever is further pushed in the direction of the arrow Z, the tip of the cantilever rides up onto the protrusion (P4) that acts as a latch, and the center portion bends sharply into a U-shape as shown in Figure 14D. In other words, because the left and right sides of the cantilever are tightly restricted by the guide from moving in the thickness direction (i.e., the up and down direction in Figure 13D), the center portion of the cantilever bends sharply to convex downward in Figure 14D.

Furthermore, as shown in Figures 14E and 14F, when the cantilever is pushed in the direction of the arrow Z, the tip of the cantilever transfers to the protrusion, and the protrusion fits into the opening (P5) of the cantilever, and the cantilever and the case are joined together.

However, when a cantilever having an opening is manufactured from resin, a weld line (WL) is likely to occur at the tip side. In other words, when a gate is formed at one point in the center of a product (for example, the center of a lid of a cover having a cantilever on the side) in order to reduce mold costs, a weld line often occurs at the tip side of the cantilever.
Therefore, as shown in Figures 14C and 14D, when the resin cantilever passes over the protrusion, it bends significantly near the weld line, and there is a problem that it is likely to crack at or near the weld line. If the cantilever cracks, the initial holding force decreases.

Even if the cantilever does not break when it passes over the protrusion, it may bend significantly near the weld line, causing the tip of the cantilever to turn white and lose strength. In that case, even after the protrusion fits into the opening of the cantilever, if the cantilever or case receives an external force (for example, an external force that causes the protrusion to come out of the opening), the cantilever is likely to break at the weld line.

For example, when an impact is applied to the cantilever, the periphery of the opening shifts to the left or right in FIG. 14E (i.e., opens to the side), making it easier for the cantilever to come loose (i.e., the cantilever to detach from the protrusion).

One aspect of the present disclosure aims to provide technology relating to a snap-fit structure that can prevent damage such as cracking of the cantilever beam and prevent the cantilever beam from coming off.

One aspect of the present disclosure is a snap fit structure that joins the first part (5) and the second part (3).
In this snap-fit structure, the first part includes a cantilever (17) that is flexible and extends from a fixed end to a free end, and a locking portion (21) that is used to connect the cantilever to the second part. The second part also includes a protrusion (19) that locks with the locking portion to restrict the movement of the cantilever, and a pair of guides (29) that guide the cantilever in a predetermined locking direction (i.e., the direction in which it moves to lock). The pair of guides are configured to cover both sides (23) in the width direction, which is perpendicular to the extension and bending directions of the cantilever, on the free end side of the cantilever.

When the locking portion is locked, with the free end of the cantilever beam positioned on the lower side and the fixed end on the upper side, the upper ends of the pair of guides are located at the same position as the lower end of the protrusion, or at a position lower than the lower end of the protrusion.

With this configuration, the snap-fit structure of the present disclosure can prevent damage such as cracking of the cantilever beam, and can also prevent the cantilever beam from coming off the protrusion. This is explained in detail below.

When joining a first part and a second part with a snap-fit structure, for example, if the cantilever of the first part is pushed into the protrusion of the second part, the cantilever rides up onto the protrusion, but at this stage, both sides of the cantilever are not restricted by a pair of guides and therefore do not bend significantly. In other words, the cantilever rides up onto the protrusion, but at this stage, the cantilever is bent at its base.

After that, when the cantilever passes over the protrusion, both sides of the free end of the cantilever (i.e., the tip side) come into contact with a pair of guides and are guided by the pair of guides in a predetermined engagement direction (for example, the gap between the guide and the wall surface on which the protrusion is provided: the inside of the guide), but at that time, the free end of the cantilever is guided inside the guide with a slight bending compared to conventional methods or without bending at all.

In this way, according to the present disclosure, when the cantilever beam rides over the protrusion, it does not bend significantly as in the past, so even if the cantilever beam is made of resin and has a weld line on the free end side, the free end side of the cantilever beam is less likely to crack. Even if it does not crack, the strength is less likely to deteriorate due to whitening.

In addition, because the cantilever is less likely to crack, abnormal wear is less likely to occur on the cantilever even when vibrations are applied to the various components. Furthermore, even if an impact is applied to the cantilever, the periphery of the engagement portion (e.g., the opening) opens sideways, preventing the cantilever from coming off the protrusion.

The snap-fit structure disclosed herein therefore has the remarkable effect of preventing damage such as cracking of the cantilever beam and preventing the cantilever beam from coming off, thereby achieving a good connection between the first and second components.

The reference characters in parentheses in this section and in the claims indicate the correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of this disclosure.

FIG. 2 is an exploded perspective view of the housing of the first embodiment. FIG. 2 is an enlarged perspective view showing a snap-fit structure of the first embodiment. FIG. 3A is a front view showing a cantilever beam of the first embodiment, and FIG. 3B is a cross-sectional view taken along line IIIB-IIIB of FIG. 3A. 4A is a plan view showing the protrusions etc. of the first embodiment, FIG. 4B is a front view of the protrusions etc., FIG. 4C is a side view of the protrusions etc., and FIG. 4D is a front view of the protrusions etc. of a modified example. FIG. 5A is a plan view showing the guide etc. of the first embodiment, FIG. 5B is a front view of the guide etc., and FIG. 5C is a side view of the guide etc. 3B is an explanatory diagram showing the positional relationship between the cantilever beam, the guide, and the protrusion portion in the first embodiment in the IIIB-IIIB cross section of FIG. 3A. The steps for joining the case and cover in the first embodiment are shown in FIG. 7A, where FIG. 7B is a cross-sectional view taken along line VIIB-VIIB of FIG. 7A, FIG. 7C is a front view of the cantilever beams etc. in the next step, FIG. 7D is a cross-sectional view taken along line VIID-VIID of FIG. 7C, FIG. 7E is a cross-sectional view taken along line VIIE-VIIE of FIG. 7C, FIG. 7F is a front view of the cantilever beams etc. in the next step, and FIG. 7G is a cross-sectional view taken along line VIIF-VIIF of FIG. 7F. FIG. 8A is a front view showing a cantilever beam of the second embodiment, and FIG. 8B is a cross-sectional view taken along line VIIIB-VIIIB of FIG. 8A. 8B is an explanatory diagram showing the positional relationship between the cantilever beam and the protrusion portion in the second embodiment in the VIIIB-VIIIB cross section of FIG. 8A. FIG. 11 is a plan view showing a cantilever beam of a modified example of the second embodiment cut in the ZX plane and its surrounding structure. 11A is a plan view showing a snap-fit structure of the third embodiment from the inside of a housing, and FIG. 11B is a cross-sectional view taken along the line XIB-XIB of FIG. 11A. 12A is a plan view showing a snap-fit structure of the fourth embodiment from the inside of a housing, and FIG. 12B is a cross-sectional view taken along line XIIB-XIIB of FIG. 12A. 13A is a plan view showing protrusions etc. of another embodiment, FIG. 13B is a front view of the protrusions etc., and FIG. 13C is a side view of the protrusions etc. FIG. 1 is an explanatory diagram of a conventional technique.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.
[1. First embodiment]
[1-1. Overall configuration]
As shown in FIG. 1, the housing 1 of the first embodiment is a container having a box-shaped case 3 and a box-shaped cover 5 that fits inside the case 3, and the case 3 and the cover 5 can be joined together by a snap-fit structure described later.

The case 3 is made of resin (for example, PBT resin). PBT is polybutylene terephthalate. The case 3 is a roughly rectangular parallelepiped container that is open at the top in the Z-axis direction.

In more detail, the case 3 comprises a flat bottom 7 arranged along the XY plane, and rectangular frame-shaped case sides 9 erected vertically from the bottom 7 along the outer periphery of the bottom 7 (e.g. erected upward in FIG. 1). The case sides 9 are long plate-shaped members arranged in a strip shape surrounding the periphery of the bottom 7 so as to be perpendicular to the bottom 7.

As will be described in detail later, case engagement parts 11 that form part of the snap-fit structure are provided at multiple locations (e.g., six locations) on the inside of the case side part 9. Note that only some of the case engagement parts 11 (i.e., three locations) are shown in Figure 1.

The cover 5 is a container that is fitted inside the case 3 on the opening 12 side of the case 3 so as to close the opening 12. The cover 5 is made of resin (e.g., PBT resin). The cover 5 is a container that is roughly rectangular and has an opening on the lower side in the Z-axis direction.

In more detail, the cover 5 comprises a plate-shaped lid portion 13 arranged along the XY plane, and a rectangular frame-shaped cover side portion 15 that stands vertically from the lid portion 13 along the outer periphery of the lid portion 13 (e.g., stands downward in FIG. 1). The cover side portion 15 is a long plate-shaped member that is arranged in a band shape surrounding the periphery of the lid portion 13 so as to be perpendicular to the lid portion 13.

This cover side portion 15 has cover engagement portions 16 at multiple locations (e.g., six locations) that constitute part of the snap-fit structure. Note that only some of the cover engagement portions 16 (i.e., three locations) are shown in Figure 1.

In the first embodiment, each case engaging portion 11 and each cover engaging portion 16 engage with each other (i.e., engage with each other) to integrally connect the case 3 and the cover 5. In more detail, the elasticity of the material (e.g., the elasticity of the cover 5) is utilized so that one of the engaging members stops (i.e., engages) the other, forming a snap-fit structure to integrally connect the case 3 and the cover 5.

In the XYZ coordinate system, the vertical direction in FIG. 1 (i.e., the thickness direction of the housing 1) is the Z-axis direction, and when viewed from the Z-axis direction, the longitudinal direction of the housing 1 is the X-axis direction and the lateral direction is the Y-axis direction.

Each configuration will be described in detail below.
[1-2. Snap-fit structure]
Next, the snap-fit structure will be described with reference to Fig. 2 and other figures. Note that the six snap-fit structures are basically the same, so a single snap-fit structure will be described as an example. Note that Fig. 2 shows an enlarged view of the snap-fit structure arranged on the long side of the housing 1 as viewed from inside the housing 1.

As shown in FIG. 2 , the snap-fit structure includes a case engaging portion 11 and a cover engaging portion 16 .
<Cover engagement portion>
The cover engagement portion 16 is provided with a cantilever 17 extending from one end of the cover side portion 15 to the opposite side of the lid portion 13 (i.e., the bottom 7 side of the case 3 to which it is joined) along the erection direction of the cover side portion 15. Note that the cover side portion 15 has rectangular notches 25 formed along the left and right side portions 23 of the cantilever 17 so that the cantilever 17 can be easily bent.

The cantilever 17 is a rectangular member that extends along the ZX plane from one end of the cover side portion 15 (i.e., its shape when viewed from the Y-axis direction is rectangular). In other words, the cantilever 17 is a plate-like member that has one end of the cover side portion 15 as a fixed end and extends downward in FIG. 2 from the fixed end to a free end.

As shown in FIG. 3A, an opening 21 is provided on the free end side (i.e., the tip side) of the cantilever beam 17, which is engaged with a protrusion 19 (see, for example, FIG. 2), which is a latch described below. This opening 21 is a through hole that penetrates the cantilever beam 17 in the thickness direction (i.e., the plate thickness direction, which is the Y-axis direction). The shape of the opening 21 is, for example, approximately rectangular when viewed from the Y-axis direction, but the side on the fixed end side (i.e., the base side) is curved into an approximately semicircular shape. The shape of the opening 21 may also be rectangular.

Furthermore, as shown in FIG. 3B, the free end side of the cantilever beam 17, i.e., the tip portion 27 on the tip side of the opening 21, has a thickness dimension that becomes smaller toward the tip. In other words, the tip portion 27 has a tapered portion 28 that is tapered when viewed from the X-axis direction.

Note that the left-right direction in the X-axis direction in FIG. 3A is the width direction of the cantilever beam 17, the direction perpendicular to the width direction (i.e., the Z-axis direction) is the direction in which the cantilever beam 17 extends, and the Y-axis direction is the direction in which the cantilever beam 17 bends (i.e., the plate thickness direction).

<Case engagement part>
As shown in FIG. 2, the case engagement portion 11 includes a protrusion 19 configured to fit into the opening 21, and a pair of left and right guides 29 configured to guide the left and right side portions 23 of the cantilever beam 17.

Of these, the protrusion 19 is a locking member that engages with the opening 21, specifically with a part of the inner circumferential surface 21a of the opening 21 (i.e., the lower surface of the inner circumferential surface 21a in FIG. 2), and restricts the movement of the cantilever beam 17 upward in FIG. 2 (i.e., in the direction in which the cantilever beam 17 comes off).

The protrusion 19 is generally wedge-shaped such that the thickness at its rear end (i.e., the upper side in FIG. 2 : the side of the opening 12 of the case 3 ) is thinner than that at its tip end (i.e., the lower side in FIG. 2 : the side of the bottom 7 of the case 3 ).
In detail, as shown in Figures 4A to 4C, the protrusion 19 has a rectangular prism-shaped tip portion 31 and a triangular prism-shaped inclined portion 33 connected to the rear end side of the tip portion 31 (i.e., the upper side in Figure 4B).

As a result, as shown in FIG. 4C, the surface 31a of the top of the tip 31 of the protrusion 19 protrudes highest above the inner peripheral surface 9a of the case side portion 9, and the height of the inclined surface (i.e., the protrusion-side inclined surface) 35 of the inclined portion 33 gradually decreases from the surface 31a toward the rear end. In other words, the protrusion-side inclined surface 35 is inclined at a predetermined angle α, which will be described later. Note that α is within a predetermined range in which the cantilever beam 17 can be engaged, within the range of "0°<α<90°", as will be described later.

As another shape of the protrusion 19, for example, as shown in FIG. 4D, the planar shape of the inclined portion 33 (i.e., the shape as seen from the Y-axis direction) may be a circle or an oval that is curved so as to be convex toward the rear end. In this case, the planar shape of the opening 21 may also be a shape that follows the outer periphery of the protrusion 19.

<Guide>
Next, the pair of guides 29 will be described.
2, the pair of guides 29 are members that guide the cantilever 17 in a predetermined locking direction (i.e., the direction in which the cantilever 17 is moved when locked: downward in FIG. 2). The pair of guides 29 are configured to cover both side portions 23 in the width direction, which is perpendicular to the extension direction (i.e., Z-axis direction) and bending direction (i.e., Y-axis direction) of the cantilever 17 on the free end side of the cantilever 17 (i.e., X-direction).

In addition, since the pair of guides 29 are symmetrical (for example, line symmetrical when viewed from the Z-axis direction), the following description will be given taking one of the guides 29 (for example, the left side in FIG. 2) as an example.
As shown in FIG. 5, the guide 29 is a columnar member extending in the Z-axis direction from the bottom 7 of the case 3 along the case side 9, and has an L-shape when viewed in the Z-axis direction.

In more detail, the guide 29 is composed of a plate-shaped first restricting portion 37 and a plate-shaped second restricting portion 39, and the first restricting portion 37 and the second restricting portion 39 are connected perpendicularly when viewed from the Z-axis direction, forming the L-shape. In this first embodiment, the first restricting portion 37 and the second restricting portion 39 are integrally configured.

Of these, the second restricting portions 39 are members that are erected perpendicularly to the bottom 7 and case side 9 on the surfaces of the bottom 7 and case side 9. The second restricting portions 39 restrict the movement of the cantilever 17 in the width direction. In other words, the left and right second restricting portions 39 of the pair of guides 29 restrict the movement of the cantilever 17 in the opening direction of the left and right side portions 23 of the opening 21.

On the other hand, the first restricting portion 37 is a member that is erected perpendicular to the bottom portion 7 and the second restricting portion 39 at the bottom portion 7 and the second restricting portion 39. The first restricting portion 37 restricts the movement of the cantilever beam 17 in the bending direction (for example, the left direction in FIG. 5C).

As shown enlarged in FIG. 6, a guide-side inclined surface 41 is provided on the inside (i.e., right side of FIG. 6) of the tip side (i.e., upper side of FIG. 6) of the first restricting portion 37, which is inclined so that the distance between the first restricting portion 37 and the case side portion 9 becomes narrower as it approaches the rear end side (i.e., lower side of FIG. 6) of the first restricting portion 37.

The guide-side inclined surface 41 is a plane that is inclined at a predetermined angle β with respect to the direction in which the cantilever 17 extends when the cantilever 17 is engaged with the protrusion 19 (i.e., the Z-axis direction), more specifically, with respect to the direction in which the cantilever 17 spreads (i.e., the ZX plane). Note that β is within a predetermined range in which the cantilever 17 can be guided, within the range of "0°<β<90°", as described below.

In other words, as described below, when the cantilever beam 17 moves over the protrusion 19 and hits the guide 29 when the case 3 and cover 5 are joined, the guide-side inclined surface 41 is inclined so that the right side in FIG. 6 slopes downward relative to the locking direction so as to guide the free end side in a direction covered by the guide 29 (i.e., the locking direction, which is downward in FIG. 6).

In particular, in this first embodiment, the upper end of the guide 29 is located at a position lower than the lower end of the protrusion 19. In other words, in the Z-axis direction, there is a gap of Δx between the upper end of the guide 29 (i.e., the upper end of the guide-side inclined surface 41) and the lower end of the protrusion 19. Note that the position of the upper end of the guide 29 and the position of the lower end of the protrusion 19 may be the same.

The range of Δx can be set appropriately within a range in which, when the cantilever 17 is engaged with the protrusion 19, the tip 27 of the cantilever 17 comes into contact with the guide 29 (e.g., the guide-side inclined surface 41) and the cantilever 17 can be guided downward in FIG. 6 (i.e., in the engagement direction of the cantilever 17).

Furthermore, in this first embodiment, when viewed from the X-axis direction, the guide-side inclined surface 41 of the guide 29 is configured to exist on the extension line of the protrusion-side inclined surface 35 of the inclined portion 33 of the protrusion 19 (i.e., see the dashed arrow in Figure 6).

[1-3. Joining method]
Next, a method for joining the case 3 and the cover 5 will be described with reference to FIG.
7, the configuration of each part is shown in a schematic manner, and the shape of the protrusion 19 shown in FIG. 4D is taken as an example.

As shown in Figures 7A and 7B, first, the cover 5 is fitted so as to cover the opening 12 side of the case 3, and the cantilever beam 17 of the cover 5 is moved in the direction of the arrow Z (i.e., the locking direction) along the case side 9.

Next, as shown in Figures 7C and 7D, the cantilever 17 is further pushed in the direction of the arrow Z so that the tip side (i.e., the free end side) of the cantilever 17 rides up onto the protrusion 19. That is, the tip 27 of the cantilever 17 moves on the protrusion-side inclined surface 35. At this time, the rear end side (i.e., the fixed end side) of the cantilever 17 is bent and the tip side is raised, as shown in Figure 7E.

In this state, if the cantilever 17 is pushed further in, the tip 27 of the cantilever 17 hits the guide side inclined surface 41 of the guide 29, and the tip 27 of the cantilever 17 advances in the engagement direction and is guided into the gap between the guide side inclined surface 41 and the inner peripheral surface 9a of the case side portion 9.

In other words, the pair of guides 29 covers both widthwise sides 23 of the cantilever beam 17 and restricts the movement of the cantilever beam 17 to the left in FIG. 7E, guiding the cantilever beam 17 downward in FIG. 7E.

When the cantilever 17 is then further pressed in, as shown in Figures 7F and 7G, the tip 27 of the cantilever 17 transfers to the protrusion 19, and the protrusion 19 fits into the opening 21 of the cantilever 17. In other words, the opening 21 is locked by the protrusion 19, and the cantilever 17 itself is also locked to the protrusion 19, and is fixed so that it cannot come off.

This allows the case 3 and the cover 5 to be joined together.
[1-4. Effects]
According to the first embodiment, the following effects can be obtained.

(1a) In this first embodiment, the case 3 and the cover 5 are made of resin, and as shown in FIG. 6, the upper ends of the pair of guides 29 are located below the lower ends of the protrusions 19.

As a result, when the cantilever 17 rides over the protrusion 19, it does not bend significantly as in the past, so even if there is a weld line on the free end side of the resin cantilever 17, the free end side of the cantilever 17 is less likely to crack. Even if it does not crack, the strength is less likely to deteriorate due to whitening.

In addition, because the cantilever 17 is less likely to crack, abnormal wear is less likely to occur on the cantilever 17, etc., even when vibration is applied to the housing 1, etc. Furthermore, even if an impact is applied to the cantilever 17, etc., the tip 27 adjacent to the opening 21 is cracked, and the periphery of the opening 21 opens sideways, preventing the cantilever 17 from coming off the protrusion 19.

Therefore, in this first embodiment, damage to the cantilever beam 17 can be suppressed, and the cantilever beam 17 can be prevented from coming off the protrusion portion 19, which has the remarkable effect of achieving a good connection between the case 3 and the cover 5.

In addition, in this first embodiment, the height of the guide 29 can be set low by providing the upper end of the guide 29 at a position lower than the lower end of the protrusion 19. This has the advantage that even when a large board is housed in the housing 1, there is little interference between the board and the guide 29.

(1b) In this first embodiment, the pair of left and right guides 29 are configured to restrict the movement of the cantilever beam 17 in the bending direction and to restrict the movement of the cantilever beam 17 in the width direction. This configuration effectively prevents the cantilever beam 17 from coming off the protrusion 19.

(1c) In this first embodiment, the free end of the cantilever 17 is provided with a tapered portion 28 that becomes thinner toward the free end. Therefore, when the cantilever 17 is pressed in, the tip 27 of the cantilever 17 can move smoothly over the protrusion 19. Furthermore, when the tip 27 of the cantilever 17 hits the guide 29, the tip 27 of the cantilever 17 can move smoothly in a direction covered by the guide 29 (for example, in the downward engagement direction in FIG. 6).

(1d) In this first embodiment, the guide 29 is provided with a guide-side inclined surface 41 at the portion where the tip 27 of the cantilever 17 abuts. Therefore, when the tip 27 of the cantilever 17 abuts on the guide-side inclined surface 41, the tip 27 of the cantilever 17 can be smoothly guided in a predetermined moving direction.

(1e) In this first embodiment, the guide side inclined surface 41 of the guide 29 is configured to exist on the extension line of the protrusion side inclined surface 35 of the inclined portion 33 of the protrusion 19. As a result, when the cantilever beam 17 is pushed in and engaged with the protrusion 19, the tip end 27 of the cantilever beam 17 reliably hits the guide side inclined surface 41, so that the cantilever beam 17 can be guided appropriately.

[1-5. Correspondence]
Next, the relationship between the first embodiment and the present disclosure will be described.
The housing 1 corresponds to the housing, the case 3 corresponds to the second part, the cover 5 corresponds to the first part, the cantilever 17 corresponds to the cantilever, the protrusion 19 corresponds to the protrusion, the opening 21 corresponds to the locking part, the side 23 corresponds to the side, the inclined part 33 corresponds to the inclined part, the guide 29 corresponds to the guide, the protrusion side inclined surface 35 corresponds to the protrusion side inclined surface, and the guide side inclined surface 41 corresponds to the guide side inclined surface 41.

[2. Second embodiment]
Since the second embodiment has a basic configuration similar to that of the first embodiment, the following description will mainly focus on the differences from the first embodiment. Note that the same reference numerals as those in the first embodiment indicate the same configurations, and the preceding description will be referred to.

In the snap-fit structure of the second embodiment, the configuration of the cantilever beam 51 is significantly different from that of the first embodiment, as shown in Fig. 8. The following description will focus on the differences.
Specifically, the cantilever beam 51 used in the second embodiment is provided with a recess 53 instead of an opening so as to be engaged with the protrusion 19 .

This recess 53 is provided in a strip shape on the outside of the cantilever 51, i.e., on the case side 9 side where the protrusion 19 is provided (for example, the right side in FIG. 8B), from the upper side of the cantilever 51 (i.e., the upper end portion of the cover side 15) to the tip 55 of the cantilever 51.

In other words, the recess 53 is a rectangular groove cut into a rectangular parallelepiped shape to have a constant depth when viewed from the Y-axis direction. As shown in FIG. 8B, the upper end of the recess 53 extends to the lid portion 13 of the cover 5, and the tip surface 53a of the recess 53 is formed perpendicular to the bottom surface 53b.

Therefore, in this second embodiment, as shown in FIG. 9, when the cantilever 51 moves in the direction of the arrow Z, the tip 55 of the cantilever 51 climbs over the protrusion 19, and the protrusion 19 fits into the recess 53. As a result, the recess 53 (i.e., the tip surface 53a of the recess 53) is engaged with the protrusion 19, and the cantilever 51 is fixed to the protrusion 19.

The second embodiment provides the same effects as the first embodiment.
In the second embodiment, when the resin cover 5 is manufactured using a mold, the upper and lower molds can be removed, so that the manufacturing process can be simplified.

The second embodiment has the advantage that when the cover 5 is fitted to the case 3, it is possible to visually check whether the protrusion 19 is engaged with the recess 53 of the cantilever 17 by looking from the lid portion 13 side of the cover 5.

In this second embodiment, when the cover 5 is fitted to the case 3, the recess 53 of the cantilever 17 has a bag structure with no opening that opens to the inside of the housing 1, so even if water gets into the gap between the cantilever 17 and the case side 9, the water is less likely to enter the inside of the housing 1.

<Modification>
As shown in FIG. 10, a pair of left and right crush ribs 57 may be provided on the inner side of the cantilever beam 51 (i.e., on the inner side of the cover 5).

Specifically, the crush rib 57 is provided on the inside of the cantilever beam 51, on the inside of the left and right side portions 59, i.e., on the portions facing the first restricting portions 37 of the left and right guides 29, in a convex shape so as to reach the first restricting portions 37. The crush rib 57 is provided on the inside of the cantilever beam 51, along the Y-axis direction, so as to reach from the upper end to the lower end of the cantilever beam 51. The thickness (i.e., the dimension in the Y-axis direction) of the crush rib 57 is set so as to slightly press against the first restricting portions 37.

By providing the crush rib 57 in this manner, the crush rib 57 and the first restricting portion 37 are in close contact under pressure, improving the adhesion between the cover 5 and the case 3. This makes it possible to suppress the generation of abnormal noise. It also improves waterproofing.

[3. Third embodiment]
Since the third embodiment has a basic configuration similar to that of the first embodiment, the following description will be focused mainly on the differences from the first embodiment. Note that the same reference numerals as those in the first embodiment indicate the same configurations, and the preceding description will be referred to.

In the snap-fit structure of the third embodiment, as shown in FIG. 11, each of the pair of left and right guides 61 has a first restricting portion 63 and a second restricting portion 65, but the first restricting portion 63 and the second restricting portion 65 of each guide 61 are configured separately.

In other words, in the third embodiment, the first restricting portion 63 that restricts the movement of the cantilever beam 17 in the bending direction (i.e., the up-down direction in FIG. 11B) and the second restricting portion 65 that restricts the movement of the cantilever beam 17 in the width direction (i.e., the left-right direction in FIG. 11B) are provided at different positions.

The first restricting portion 63 is a plate-like member that stands vertically from the bottom portion 7 of the case 3 toward the upper side in FIG. 11A, and is disposed parallel to the case side portion 9. The thickness direction of the first restricting portion 63 is the same as the bending direction of the cantilever beam 17, and the tip side of the first restricting portion 63 can bend in the same direction as the cantilever beam 17. The inside of the tip of the first restricting portion 63 (i.e., the upper side in FIG. 11B) is provided with a guide-side inclined surface 67 that is inclined in the same way as the first embodiment.

The second restricting parts 65 are plate-like or column-like members that stand vertically from the bottom part 7 of the case 3 toward the upper part in FIG. 11A, and are disposed on the outside of the left and right side parts 23 of the cantilever beam 17, respectively. The pair of left and right second restricting parts 65 are disposed in parallel.

The third embodiment provides the same effects as the first embodiment.
Furthermore, in the third embodiment, the cantilever 17 can be easily locked, and the cantilever 17 locked to the protrusion 19 is unlikely to come off.

Specifically, since the first restricting portion 63 is a cantilever beam having flexibility as described above, if, for example, the distance between the first restricting portion 63 and the case side portion 9 is set narrower than in the first embodiment, when the tip portion 27 of the cantilever beam 17 hits the guide side inclined surface 67 of the first restricting portion 63 when the cantilever beam 17 is pushed in, the tip side of the first restricting portion 63 bends slightly away from the case side portion 9 (i.e., opens).

After that, when the cantilever 17 is further pushed in, it is guided by the first restricting portion 63 and moves forward, and the protrusion 19 fits into the opening 21, and the cantilever 17 is locked to the protrusion 19. At this time, the tip 27 of the cantilever 17 approaches or comes into contact with the case side portion 9, so that the first restricting portion 63 returns to its original bending state and becomes straight.

With this configuration, when the cantilever beam 17 is pushed in, the tip side of the first restricting portion 63 bends, so that the cantilever beam 17 can be easily pushed in, and therefore the cantilever beam 17 can be easily locked.

In addition, after the cantilever beam 17 is locked, the downward movement of the cantilever beam 17 in FIG. 11B is restricted by the first restricting portion 63, which has returned to its original deflection, so that the cantilever beam 17 is even less likely to fall off the protrusion portion 19.

[4. Fourth embodiment]
Since the fourth embodiment has a basic configuration similar to that of the first embodiment, the following description will mainly focus on the differences from the first embodiment. Note that the same reference numerals as those in the first embodiment indicate the same configurations, and the preceding description will be referred to.

In the snap-fit structure of the fourth embodiment, as shown in FIG. 12, each guide 71 is not L-shaped as in the first embodiment, but has a substantially flat plate shape.
In the fourth embodiment, a plate-like guide 71 is provided vertically upward from the bottom 7 of the case 3 in FIG. 12A.

The guide 71 is disposed at an angle to the case side 9. That is, the left and right guides 71 are disposed in a generally V-shaped position such that the distance between them decreases the farther they are from the case side 9. In other words, the guide 71 is configured to restrict movement of the cantilever 17 in the bending direction (i.e., downward in FIG. 12B) and to restrict movement of the cantilever 17 in the width direction (i.e., left and right in FIG. 12B).

The guide 71 has a guide-side inclined surface 73 on the inner side of the tip thereof (i.e., on the protrusion 19 side) that is inclined in the same manner as in the first embodiment.
The fourth embodiment has the same effects as the first embodiment, and further has a simplified configuration and can reduce the amount of material used.

5. Other embodiments
Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms.

(5a) For example, if the cantilever beam can be guided by a guide, it is possible to omit the inclined surface or tapered portion on the guide side.
(5b) The shapes and arrangements of each component, such as the guide, protrusion, cantilever, etc., may be of various shapes and arrangements as long as the effects of the present disclosure are achieved.

For example, as shown in FIG. 13, the guide 29 of the first embodiment may be configured so that a portion of the first restricting portion 37 on the case side 9 side (i.e., the lower side in FIG. 13C) reaches the case side 9. In other words, when the cantilever 17 is engaged with the protrusion 19, there may be no gap between the first restricting portion 37 and the case side 9 on the tip side of the tip of the cantilever 17 (i.e., the lower side in FIG. 13C).

(5c) Examples of materials for resin cases and covers include materials made of resin, or materials made of resin with additives added. For example, a material with the largest proportion of resin components (i.e., a material with resin as the main component) can be used.

(5d) Multiple functions possessed by one component in each of the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another embodiment.

1...Housing, 3...Case, 5...Cover, 17, 51...Cantilever, 19...Protrusion, 21...Opening, 23...Side, 29, 61, 71...Guide, 33...Inclined portion, 35...Protrusion side inclined surface, 41, 61...Guide side inclined surface

Claims (8)

A snap-fit structure for connecting a first part (5) and a second part (3),
The first component includes a cantilever (17) that is flexible and extends from a fixed end side to a free end side, and the cantilever includes a locking portion (21) that is used for coupling with the second component;
The second part includes a protrusion (19) that engages with the engaging portion to restrict movement of the cantilever beam, and a pair of guides (29) that guide the cantilever beam in a predetermined engaging direction,
The pair of guides are configured to cover both side portions (23) in a width direction perpendicular to the extending direction and bending direction of the cantilever beam at the free end side of the cantilever beam,
when the locking portion is locked, and when the free end side of the cantilever beam is the lower side and the fixed end side is the upper side, upper ends of the pair of guides are provided at the same position as the lower end of the protrusion or at a position lower than the lower end of the protrusion ,
When the first part and the second part are joined, in the case where the free end side of the cantilever moves on the protrusion and hits the pair of guides, a guide side inclined surface (41) inclined with respect to the locking direction is provided at the portion where the free end side of the pair of guides hits so as to guide the free end side in the locking direction.
Snap fit construction. 2. The snap-fit structure of claim 1,
The protrusion has an inclined portion (33) whose thickness decreases toward the upper side,
The guide-side inclined surfaces of the pair of guides are configured to exist on an extension line of a protrusion-side inclined surface (35) which is an inclined surface of the inclined portion.
Snap fit construction. The snap-fit structure according to claim 1 or 2 ,
The locking portion is a through hole or a recess provided in the cantilever beam.
Snap fit construction. A snap-fit structure according to any one of claims 1 to 3 ,
At least one of the pair of guides is configured to restrict movement of the cantilever beam in the bending direction and to restrict movement of the cantilever beam in the width direction.
Snap fit construction. A snap-fit structure according to any one of claims 1 to 3 ,
At least one of the pair of guides includes a first regulating portion (63) that regulates the movement of the cantilever beam in the bending direction, and a second regulating portion (65) that is configured separately from the first regulating portion and regulates the movement of the cantilever beam in the width direction.
Snap fit construction. A snap-fit structure according to any one of claims 1 to 5 ,
A tapered portion (28) is provided on the free end side of the cantilever beam, the thickness of which decreases toward the free end side.
Snap fit construction. A snap-fit structure according to any one of claims 1 to 6 ,
The first part and the second part are made of resin.
Snap fit construction. A snap-fit structure according to any one of claims 1 to 7 ,
Housing.

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