JP7779676B2 - Grommet - Google Patents

Description

The present invention relates to a grommet.

Conventionally, grommets are attached to the periphery of a through hole pre-formed in a plate to protect the wire from the periphery when the wire is passed through the through hole. Patent Document 1 discloses technology related to a grommet that includes a grommet body that holds the wire when the wire is passed through a through hole in a vehicle body panel (the receiving member), and an inner protector that supports the grommet body and is held on the periphery of the through hole. The outer peripheral wall of the inner protector is provided with multiple locking claws spaced equally around the circumference. When the inner protector supporting the grommet body engages with the periphery of the through hole, the locking claws elastically deform while coming into contact with the periphery of the through hole, and are ultimately locked onto the periphery of the through hole.

Japanese Patent Application Laid-Open No. 2018-186623

In the grommet disclosed in Patent Document 1, the locking claws bend easily when the inner protector engages with the periphery of the through-hole, so generally, the workability is good for the worker. However, depending on the structure of the inner protector, the amount of deformation of the locking claws may increase, which may result in reduced workability when inserting part of the inner protector into the through-hole or a reduction in the holding force of the locking claws, so improvements are desirable in advance.

The present invention was made in consideration of the problems inherent in the prior art. The object of the present invention is to provide a grommet that is advantageous in improving workability or holding power when attached to the periphery of a through hole in a workpiece.

A grommet according to one aspect of the present invention comprises a grommet body that holds, on the inner periphery, an electric wire that passes through a through hole in a workpiece, and an inner protector that supports the grommet body and is held on the periphery of the through hole. The inner protector has an annular main body portion through which the electric wire passes, and an inner lock that is attached to the main body portion and locks the main body portion to the periphery of the through hole when a portion of the main body portion is inserted into the through hole. The inner lock includes a locking claw that has a protrusion that contacts or engages with the periphery of the through hole and elastically deforms when the protrusion is displaced, a support portion that supports the locking claw with the side facing the inner surface of the locking claw as a space, and a rib that is attached to the support portion and extends along the position where the support portion and locking claw are connected, protruding into the space.

The present invention provides a grommet that is advantageous for improving workability or holding power when attached to the periphery of a through hole in a workpiece.

FIG. 1 is a perspective view of a grommet according to one embodiment. FIG. 2 is an exploded view of a grommet according to one embodiment. FIG. 2 is a cross-sectional view of an inner lock according to an embodiment. FIG. 10 is a bottom view of the inner lock according to one embodiment. 10A and 10B are cross-sectional views illustrating a deformed state of a locking claw in one embodiment. 10 is a cross-sectional view illustrating a deformed state of a locking claw in a comparative example. FIG.

The following describes in detail one embodiment of a grommet using the drawings. Note that the dimensional proportions in the drawings have been exaggerated for the sake of explanation and may differ from the actual proportions.

Figure 1 is a perspective view of a grommet 10 according to one embodiment. As an example, the grommet 10 is attached to the periphery of a through-hole 2 pre-formed in a vehicle body panel 1, which serves as a mounting member, and protects an electric wire W that has passed through the through-hole 2 from the periphery of the through-hole 2. The opening shape of the through-hole 2 is circular. The electric wire W may be a wire harness, which is an assembly of electric wires. In the following description, "upper" refers to the side facing the through-hole 2 when the grommet 10 is attached to the periphery of the through-hole 2, and "lower" refers to the opposite side.

Figure 2 is an exploded view of the grommet 10. The grommet 10 comprises a grommet body 11 and an inner protector 20.

The grommet body 11 is a cylindrical member that holds and routes the electric wires W on its inner periphery. The grommet body 11 is made of a flexible material such as rubber. The grommet body 11 includes a large-diameter cylindrical portion 12 and a small-diameter cylindrical portion 13.

The large-diameter cylindrical portion 12 connects to the inner protector 20. The outer diameter of the large-diameter cylindrical portion 12 is larger than the opening diameter of the through-hole 2. The large-diameter cylindrical portion 12 includes a fitting groove 14 and a lip portion 15.

The fitting groove 14 is formed in an annular shape on the inner periphery of the large-diameter cylindrical portion 12, and fits into the flange 23 of the inner protector 20 when the inner protector 20 is connected to the large-diameter cylindrical portion 12. A protrusion 16 may also be provided in part of the fitting groove 14 to engage with a recess 23a formed in part of the flange 23.

The lip portion 15 is an annular sealing portion that protrudes toward the vehicle body panel 1 from the outer peripheral edge surface 12a that faces the vehicle body panel 1. The lip portion 15 may be composed of an inner peripheral lip portion 15a and an outer peripheral lip portion 15b. When the grommet 10 is attached to the periphery of the through hole 2, the inner peripheral lip portion 15a and the outer peripheral lip portion 15b elastically deform in a direction that leans toward the outer peripheral edge surface 12a and comes into close contact with the periphery of the through hole 2 on one surface of the vehicle body panel 1. This prevents water and other substances from entering the interior of the grommet 10 from the outside through the gap between the lip portion 15 and the surface of the vehicle body panel 1 that faces the lip portion 15.

The small-diameter cylindrical portion 13 is continuous with the side of the large-diameter cylindrical portion 12 opposite the side facing the vehicle body panel 1, and holds the electric wire W on its inner periphery. In other words, the small-diameter cylindrical portion 13 has an inner surface that contacts the outer surface of the electric wire W over a predetermined length. The inner diameter of the small-diameter cylindrical portion 13 is smaller than the inner diameter of the large-diameter cylindrical portion 12, and is slightly smaller than or approximately the same as the outer diameter of the electric wire W. This prevents water and other substances from entering the interior of the grommet 10 from the outside through the gap between the inner surface of the small-diameter cylindrical portion 13 and the outer surface of the electric wire W. The small-diameter cylindrical portion 13 is made of a flexible material, so it deforms to match changes in the position of the electric wire W.

The inner protector 20 is an annular member that supports the grommet body 11 and is held on the periphery of the through-hole 2. When the inner protector 20 supports the grommet body 11, it passes the electric wires W held in the grommet body 11 through its inner periphery. The inner protector 20 is made of a material, such as resin, that is more rigid than the grommet body 11. The inner protector 20 is also composed of a pair of members, namely, a first inner member 21a and a second inner member 21b, that are divided into two by an imaginary plane that includes the central axis of the inner protector 20 itself.

The inner protector 20 generally comprises a main body 22, which is an annular structure made up of multiple walls, and a flange 23, which is an annular plate.

The main body 22 includes, for example, an outer peripheral wall 22a, an upper wall 22b, and an inner peripheral wall 22c. The outer peripheral wall 22a is a wall that faces the peripheral edge of the through hole 2 in the planar direction of the vehicle body panel 1 when the grommet 10 is attached to the peripheral edge of the through hole 2. The upper wall 22b is a wall that is continuous with the upper peripheral edge of the outer peripheral wall 22a and extends toward the inner peripheral side. The inner peripheral wall 22c is a wall that is continuous with the inner peripheral edge of the upper wall 22b and is approximately parallel to the outer peripheral wall 22a.

The flange 23 protrudes radially outward from the lower peripheral edge of the outer peripheral wall 22a. As described above, the flange 23 is fitted into the mating groove 14 when the inner protector 20 is connected to the grommet body 11. The flange 23 also has a recess 23a that aligns with the position of the protrusion 16 pre-formed in the mating groove 14 and engages with the protrusion 16 when fitted into the mating groove 14. The engagement between the recess 23a and the protrusion 16 prevents rotation of the inner protector 20 relative to the grommet body 11 around the central axis of the large-diameter cylindrical portion 12. Note that the recess 23a may be formed on each of the flanges 23 of the first inner member 21a and the second inner member 21b. Alternatively, the mating groove 14 of the grommet body 11 may have multiple protrusions 16 formed therein, each corresponding to a corresponding recess 23a.

Here, when the inner protector 20 is a combination of a pair of members, a first inner member 21a and a second inner member 21b, the first inner member 21a and the second inner member 21b may have the same semi-annular shape. Furthermore, the first inner member 21a and the second inner member 21b include two side walls 22d that abut against each other in the circumferential direction when combined with each other. One of the two side walls 22d has a claw portion 24, and the other side wall 22d has a groove portion 25 into which the claw portion 24 fits. When the first inner member 21a and the second inner member 21b are combined, the claw portion 24 of the first inner member 21a fits into the groove portion 25 of the second inner member 21b, and the claw portion 24 of the second inner member 21b fits into the groove portion 25 of the first inner member 21a.

In addition, the first inner member 21a and the second inner member 21b may be connected via, for example, a hinge portion instead of the connection mechanism using the claw portion 24 and groove portion 25. Also, while the example shown here is one in which the inner protector 20 is divided into two inner members, it may also be divided into three or more inner members.

The inner protector 20 also has multiple inner locks 30 that lock the main body 22 to the periphery of the through hole 2 when part of the main body 22 is inserted into the through hole 2. In this embodiment, the inner locks 30 are provided at four locations equally spaced circumferentially across the entire inner protector 20. That is, two inner locks 30 are provided on each of the first inner member 21a and the second inner member 21b. The number of inner locks 30 provided is not particularly limited and may be a number other than four. Since each inner lock 30 has the same shape, the following describes one inner lock 30 in detail.

Figure 3 is a cross-sectional view of the inner lock 30, corresponding to the III-III cross section of the inner protector 20 in Figure 2. Figure 3 illustrates the state of the inner lock 30 when the main body 22 is engaged with the periphery of the through-hole 2 formed in the vehicle body panel 1. Figure 4 is a bottom view of the inner lock 30, viewed from below, corresponding to the cross-sectional view of Figure 3.

In addition, in Figure 3, the vehicle body panel 1 and a portion of the through-hole 2 are shown with imaginary lines. In this embodiment, the periphery of the through-hole 2 is, as an example, part of the rising portion 1a that faces in the opposite direction to the insertion direction of the inner protector 20 into the through-hole 2. Note that the periphery of the through-hole 2 may be part of the rising portion that faces in the insertion direction of the inner protector 20, or it may simply be an open end without any rising portion.

The inner lock 30 includes a locking claw 31, a support portion, and a rib 33.

The locking claw 31 is provided along the outer peripheral wall 22a of the main body 22 and elastically deforms in a direction connecting the inside and outside of the outer peripheral wall 22a. The locking claw 31 has a protrusion 31a that contacts or engages with the periphery of the through hole 2. Here, the state in which the protrusion 31a engages with the periphery of the through hole 2 refers to the state of the protrusion 31a relative to the through hole 2 when the inner lock 30 locks the main body 22 to the periphery of the through hole 2, i.e., when the grommet 10 is attached to the periphery of the through hole 2. The protrusion 31a protrudes outward from its apex 31b, which is a ridge line along the circumferential direction of the outer peripheral wall 22a, and is always located outside the outer periphery of the outer peripheral wall 22a. In other words, the elastic deformation of the locking claw 31 occurs due to the displacement of the protrusion 31a resulting from its contact with the periphery of the through hole 2. When the protrusion 31a is engaged with the periphery of the through-hole 2, the periphery of the through-hole 2 fits into the lower end groove 31c of the protrusion 31a (see Figure 5), thereby maintaining the main body 22 in a fixed position relative to the periphery of the through-hole 2.

In addition, since the inner protector 20 has four inner locks 30 provided in the circumferential direction, the protrusions 31a of the four lock claws 31 protrude radially from the central axis of the main body 22.

The support portion supports the locking claw 31 with the side facing the inner surface 31d of the locking claw 31 as a space 32. According to the configuration of the main body 22 in this embodiment, the support portion is the upper wall 22b. In this case, the position where the support portion and the locking claw 31 connect is approximately on the outer peripheral edge of the upper wall 22b. Furthermore, the space 32 is at least a part of the spatial region formed in the main body 22, and in this embodiment, it is partially penetrated between the outer peripheral wall 22a side and the inner peripheral wall 22c side.

The rib 33 is a structural element provided on the upper wall 22b as a support portion. As shown in FIG. 3, the rib 33 protrudes from the upper wall 22b toward the space 32 facing the inner surface 31d of the locking claw 31. The height of the rib 33 from the upper wall 22b to its tip is determined within a range that prevents interference between the rib 33 and the inner surface 31d when the locking claw 31 elastically deforms toward the space 32. Furthermore, as shown in FIG. 4, the rib 33 extends along the position where the support portion and the locking claw 31 are continuous. It is desirable that both ends of the rib 33 in this extension direction are integrated with the outer wall 22a or the upper wall 22b, respectively.

The rib 33 also has a notched surface 33a located outside the range of elastic deformation of the locking claw 31. For example, the notched surface 33a is a cutout surface in the portion that the inner surface 31d of the locking claw 31 first approaches when the locking claw 31 elastically deforms toward the space 32. In this embodiment, the notched surface 33a is a surface in the rib 33 that is cut out so as to remove the edge where the tip surface of the rib 33 meets the surface facing the inner surface 31d of the locking claw 31.

Next, we will explain the function of the grommet 10.

To assemble the grommet 10, a worker first prepares the grommet body 11 with the electric wire W routed inside, and then passes the electric wire W exposed from the large-diameter cylindrical portion 12 of the grommet body 11 through the inner periphery of the inner protector 20. The inner protector 20 is pre-separated into a first inner member 21a and a second inner member 21b. Therefore, if the electric wire W has already been passed through the through-hole 2 in the vehicle body panel 1 at this stage, the worker can easily pass the electric wire W through the inner protector 20 by combining the inner members together to sandwich the electric wire W from both sides. Next, the worker elastically deforms the large-diameter cylindrical portion 12 of the grommet body 11 in the expanding direction, engaging the protrusion 16 with the recess 23a on the flange 23 of the inner protector 20, and then fitting the flange 23 into the mating groove 14 of the grommet body 11. This series of steps attaches the grommet 10 to the wire W.

Next, to attach the grommet 10 to the periphery of the through-hole 2, if the electric wire W has not yet been inserted through the through-hole 2, the worker inserts the electric wire W exposed from the inner protector 20 into the through-hole 2. Next, the worker presses the entire grommet 10 toward the through-hole 2 while inserting the main body 22 of the inner protector 20 into the through-hole 2. At this time, each locking claw 31 of the inner lock 30 elastically deforms as its protrusion 31a displaces while contacting the periphery of the through-hole 2, allowing the main body 22 to be inserted into the through-hole 2. When the main body 22 is inserted to the full insertion position, each locking claw 31 elastically returns to its original position, locking it to the periphery of the through-hole 2. When the inner protector 20 is in this locked state, the lip 15 of the grommet body 11 tightly contacts the periphery of the through-hole 2 on the surface of the vehicle body panel 1. In other words, the vehicle body panel 1 is clamped between the protrusion 31a on the inner protector 20 side and the lip portion 15 on the grommet body 11 side. As a result, the grommet 10 is attached to the periphery of the through hole 2 so as to close the through hole 2.

Furthermore, regarding the installation of the grommet 10, we will explain in detail, particularly the elastic deformation of the locking claw 31 when inserting the main body 22 of the inner protector 20 into the through-hole 2.

Figure 5 is a cross-sectional view illustrating the deformed state of the locking claw 31. Based on the main part of the cross-sectional view of the inner lock 30 shown in Figure 3, Figure 5 depicts the state of the locking claw 31 while the main body 22 is inserted into the through-hole 2.

As the main body 22 begins to be inserted into the through-hole 2, the protrusion 31a of the locking claw 31 comes into contact with the periphery of the through-hole 2. As shown in FIG. 5 , as the main body 22 is inserted in the insertion direction indicated by the outline arrow, the protrusion 31a is pressed against the periphery of the through-hole 2, and the locking claw 31 elastically deforms so that it gradually fits into the space 32. The inner lock 30 has a rib 33 on the upper wall 22b, which serves as a support. Therefore, the elastic deformation of the locking claw 31 occurs with the apex 31b of the protrusion 31a acting as a force point, and the region of the base of the rib 33 closest to the locking claw 31 acting as a base point BP (fulcrum). As described above, the rib 33 extends along the line where the upper wall 22b and the locking claw 31 join, so the base point BP is located close to the locking claw 31.

Figure 6 is a cross-sectional view illustrating the deformation state of the locking claw 131 in an inner lock 130 that does not have a rib 33, as a comparative example. In Figure 6, the inner lock 130 and the vehicle body panel 1 having the through hole 2 are drawn in accordance with Figure 5.

The inner lock 130 includes a locking claw 131 that has the same shape as the locking claw 31 described above. The locking claw 131 has a protrusion 131a on which a vertex 131b is formed. Meanwhile, the other components included in the inner lock 130 are the same as the components included in the inner lock 30 described above. In other words, the only difference between the inner lock 130 and the inner lock 30 is that the rib 33 is not present.

As with the inner lock 30, as the main body 22 is inserted, the protrusion 131a is pressed against the periphery of the through-hole 2, causing the locking claw 131 to elastically deform and gradually move into the space 32. As with the inner lock 30, the apex 131b of the protrusion 131a serves as the force point for the elastic deformation of the locking claw 131, just as with the inner lock 30. However, since the inner lock 130 does not have a rib 33, depending on the structure of the main body 22, a portion of the upper wall 22b, which serves as a support, may also elastically deform in response to the elastic deformation of the locking claw 131. If a portion of the upper wall 22b also elastically deforms in this way, the base point BP of the locking claw 131 during elastic deformation is a region of the upper wall 22b that is spaced from the position continuous with the locking claw 131. In other words, the distance between the base point BP and the apex 131b in the inner lock 130 is longer than the distance between the base point BP and the apex 31b in the inner lock 30.

As shown in Figure 6, when the base point BP of the inner lock 130 is located relatively far from the apex 131b, the stroke amount L2 required for the locking claw 131 to elastically deform and engage tends to be large. The greater the stroke amount L2, the greater the amount of elastic deformation (overlap amount) of the locking claw 131, and as a result, the greater the force required by the operator to insert the main body 22 into the through-hole 2.

In contrast, as shown in Figure 5, when the base point BP of the inner lock 30 is located relatively close to the apex 31b, the stroke amount L1 required for the locking claw 31 to enter the locked state upon elastic deformation is smaller than the stroke amount L2 required when the rib 33 is not present. Therefore, the amount of elastic deformation of the locking claw 31 is less than when the rib 33 is not present, and as a result, the force required by the operator to insert the main body 22 into the through-hole 2 is reduced.

On the other hand, even when the grommet 10 is attached to the periphery of the through-hole 2, the inner lock 30 has a rib 33 provided on the upper wall 22b, which improves the rigidity of the upper wall 22b serving as a support for the locking claw 31, or of the main body 22 including the upper wall 22b. This improves the holding force of the locking claw 31 to hold the inner protector 20 against the periphery of the through-hole 2.

Next, we will explain the effects of the grommet 10.

The grommet 10 according to this embodiment includes a grommet body 11 that holds an electric wire W, which passes through a through hole 2 in a vehicle body panel 1 serving as an attachment member, on its inner periphery, and an inner protector 20 that supports the grommet body 11 and is held on the periphery of the through hole 2. The inner protector 20 has an annular main body 22 through which the electric wire W passes, and an inner lock 30 that is provided on the main body 22 and locks the main body 22 to the periphery of the through hole 2 when a portion of the main body 22 is inserted into the through hole 2. The inner lock 30 has a lock claw 31 that has a protrusion 31a that contacts or engages with the periphery of the through hole 2 and elastically deforms when the protrusion 31a is displaced, and an upper wall 22b that serves as a support for the lock claw 31, with the side facing the inner surface 31d of the lock claw 31 forming a space 32. Furthermore, the inner lock 30 includes a rib 33 that is attached to the support portion, extends along the position where the support portion and the locking claw 31 are connected, and protrudes into the space 32.

First, in the grommet 10, the inner lock 30 includes a rib 33 that extends along the connection between the support portion, which is, for example, the upper wall 22b, and the locking claw 31 and protrudes into the space 32. Therefore, as described above, when a portion of the main body 22 is inserted into the through hole 2, the elastic deformation of the locking claw 31 occurs from the base point BP, which is the region of the base of the rib 33 that is closest to the locking claw 31. The position of this base point BP is closer to the locking claw 31 than the base point BP that would be expected if the rib 33 were not present. This reduces the stroke amount required to engage the locking claw 31 during elastic deformation, and reduces the amount of elastic deformation of the locking claw 31 compared to when the rib 33 is not present. This reduces the force required by the operator to insert the main body 22 into the through hole 2, improving the ease of installation of the grommet 10 around the periphery of the through hole 2.

In addition, because the grommet 10 has ribs 33 provided on the support portion, the rigidity of the support portion or the main body portion 22 including the support portion can be improved. This improves the holding force of the locking claws 31 to hold the inner protector 20 against the periphery of the through hole 2.

As described above, this embodiment provides a grommet 10 that is advantageous for improving workability or holding power when attached to the periphery of a through hole 2 in an attachment member such as a vehicle body panel 1.

Furthermore, in the grommet 10 according to this embodiment, the rib 33 may have a notched surface 33a located outside the range of elastic deformation of the locking claw 31.

With this grommet 10, even if a rib 33 that protrudes into the space 32 is provided on the support part, the locking claw 31 does not interfere with the rib 33 when it elastically deforms toward the space 32. Therefore, when attaching the grommet 10 to the periphery of the through hole 2, it is possible to prevent a situation in which the locking claw 31 does not elastically deform enough, resulting in the inner protector 20 being unable to be locked.

Furthermore, by providing the cutout surface 33a on the rib 33, the rib 33 can be set larger than if the cutout surface 33a was not provided and the rib 33 were sized to be positioned outside the range of elastic deformation of the locking claw 31. This further improves the rigidity of the support portion or the main body portion 22 including the support portion, and ultimately further improves the holding force of the locking claw 31.

In addition, in the grommet 10 according to this embodiment, the grommet body 11 may have an annular lip portion 15 that comes into close contact with the peripheral surface of the through hole 2 when the inner lock 30 engages the main body portion 22 with the peripheral edge of the through hole 2.

By including the lip portion 15 on the grommet body 11, the grommet 10 attached to the periphery of the through-hole 2 is highly watertight, as it prevents water and other contaminants from penetrating from the outside to the inside of the grommet 10 through the gap between the lip portion 15 and the surface of the attachment member. Furthermore, with this grommet 10, the inner lock 30 includes a rib 33, which, as described above, further improves the holding force of the locking claw 31, thereby further improving watertightness.

Although one embodiment has been described above, the embodiment is not limited to this, and various modifications are possible within the scope of the gist of the embodiment.

REFERENCE SIGNS LIST 1 vehicle body panel 2 through-hole 10 grommet 11 grommet body 15 lip portion 20 inner protector 22 body portion 22b upper wall 30 inner lock 31 locking claw 31a protrusion portion 31d inner surface 32 space portion 33 rib 33a notched surface W electric wire

Claims (2)

a grommet body that holds, on an inner periphery thereof, an electric wire that passes through a through hole in a mounting member;
an inner protector that supports the grommet body and is held on the periphery of the through hole,
The inner protector is
an annular main body portion through which the electric wire passes;
an inner lock provided on the main body portion, which locks the main body portion to the periphery of the through hole when a part of the main body portion is inserted into the through hole,
The inner lock is
a locking claw having a protrusion that contacts or engages with the periphery of the through hole and that is elastically deformed by displacement of the protrusion;
a support portion that supports the locking claw with a space on the side facing the inner surface of the locking claw;
a rib provided on the support portion, extending along a position where the support portion and the locking claw are continuous, and protruding into the space,
The rib has a notched surface positioned outside the range of elastic deformation of the locking claw, and does not interfere with the rib when the locking claw is elastically deformed into the space.
Grommet. The grommet according to claim 1 , wherein the grommet body has an annular lip portion that comes into close contact with the peripheral surface of the through hole when the inner lock engages the body portion with the peripheral edge of the through hole.