JP4668055B2 - Tubular member mounting structure - Google Patents

Description

  The present invention relates to a tubular member mounting structure in which a tubular member is detachably attached to a synthetic resin main body such as an air cleaner case of an internal combustion engine by a so-called bayonet mount system.

  Patent Document 1 discloses a configuration in which when a duct is attached to a resonator case made of synthetic resin, a plurality of locking claws are engaged by being press-fitted into locking holes. In other words, in this case, the duct is assembled by strongly pushing it toward the resonator case.

On the other hand, in Patent Document 2, a plurality of protrusions projecting in the radial direction are provided at the distal end portion of the communicating pipe of the resonator, and after inserting these protrusions through the notches provided in the periphery of the attachment hole of the resonator, A so-called bayonet mount mounting structure is disclosed in which each protrusion is engaged with the back side of the case wall portion by rotating it to one side until it abuts.
JP 2003-254182 A JP 2005-188440 A

  In the mounting structure by the press-fitting of the locking claw as in Patent Document 1, there is generally some rattling between the tubular member and the case side, abnormal noise and wear occur, and no seal member is interposed. And a seal | sticker is hardly made at the junction part of a tubular member and a case.

  On the other hand, in the bayonet mount type as in Patent Document 2, in general, some uneven parts such as a stopper part and an engaging part are required inside the case. For this reason, for example, a case is formed by injection molding. In addition, there is a problem that a complicated movable core is required inside the case where space is limited. Moreover, in patent document 2, it is not the structure which clamps a communicating pipe | tube positively to a case, but has aimed at sealing by packing fundamentally.

  In view of this, the present invention is intended to secure a firm fastening and secure a sealing property by using a slight deformation of the synthetic resin itself without providing an uneven portion on the inner surface of the synthetic resin main body.

  That is, the present invention includes a synthetic resin main body having a wall portion having a predetermined thickness with a circular attachment hole opened, and a synthetic resin tubular member detachably attached to the attachment hole. A tubular member mounting structure that is attached by rotating the member in the first rotation direction and removable by rotating in the second rotation direction, wherein the main body has at least a peripheral edge of the mounting hole. A notch part formed in two notches, a holding part adjacent to the notch part in the circumferential direction along the first rotation direction, and a predetermined angle away from the holding part in the first rotation direction; And a step formed in the outer surface of the wall so as to serve as a stopper in the rotational direction. On the other hand, the tubular member is provided at a base portion of the tubular member, and has a flange portion that is in close contact with the outer surface of the wall portion around the attachment hole, and enters the attachment hole from the flange portion. An extension that extends in the axial direction, and a shape that protrudes radially from the outer peripheral surface of the extension, can be inserted through the notch, and is slightly smaller than the wall thickness between the flange and the flange surface. At least two projecting pieces constituting a small gap, an inclined surface for guiding the holding unit provided at an end of the projecting piece facing the holding unit, and a predetermined angle at which the projecting piece meshes with the holding unit And a stopper portion protruding from the flange surface so as to engage with the step at a position.

  The tubular member is attached by inserting the projecting piece through the notch and then turning the tubular member by a predetermined angle in the first rotation direction. At this time, the holding portion on the main body side having a predetermined thickness enters the gap between the protruding piece and the flange surface, but this gap is slightly smaller than the thickness of the holding portion, and the elastic deformation of the synthetic resin material Since it is press-fitted with (bending deformation of the projecting piece, compression deformation of the holding portion, etc.), the flange portion is pulled inward, and the flange surface comes into pressure contact with the outer surface of the wall portion around the mounting hole. As a result, a firm support without rattling is achieved and a sufficient sealing performance is obtained. When the protruding piece reaches the holding portion, the holding portion is smoothly guided by the inclined surface for guiding the holding portion of the protruding piece. And if a tubular member is rotated to a predetermined position, the stopper part which protruded slightly from the flange surface will engage with the level | step difference by the side of a main body, and will be positioned.

  Further, when removing the tubular member, the tubular member may be rotated in the second rotational direction against the engagement holding force between the step and the stopper portion.

  One desirable aspect of the present invention further includes a second stopper mechanism for restricting excessive rotation in the first rotation direction. That is, the second stopper mechanism is constituted by the main body side portion and the tubular member side portion respectively provided on the main body and the tubular member so that the tubular member contacts each other at a position rotated by a predetermined angle in the first rotation direction. Is configured.

  Moreover, in one aspect of the present invention, the stopper portion has an inclined surface in which the protruding amount from the flange surface gradually increases in the circumferential direction. Thereby, the force required for the rotation operation does not increase rapidly, and the operation at the time of attachment becomes easy.

  More preferably, it has a main body side inclined surface recessed on the main body side so as to coincide with the inclined surface of the stopper portion at an initial position where the protruding piece is inserted into the notch portion. The step is formed between the surface and the recess adjacent to the surface. In this case, when the rotation operation is performed, the inclined surfaces that match each other are in sliding contact with each other, and the rotation operation can be easily performed without causing local wear or the like. In addition, since said main body side inclined surface and adjacent recessed part are also formed in the outer surface of a main body, it is not necessary to shape | mold an unevenness | corrugation in an inner surface.

  According to the present invention, the elastic deformation of the synthetic resin material can be used to strongly bring the flange portion into close contact with the outer surface of the main body. Can be secured. And since there is no need to form irregularities on the inner surface of the main body, for example, when mounting holes are provided in the side wall of the box-shaped main body, the mounting hole portion is injection molded without using a complicated movable core on the inside. It becomes possible to mold by.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an air cleaner case of an air cleaner for an internal combustion engine to which the mounting structure of the present invention is applied. This air cleaner case is roughly divided into two along a dividing surface 3 on a body 1 serving as a clean side and a cover 2 serving as a dust side, and an air cleaner element (not shown) is sandwiched therebetween. The cover 2 is provided with an intake inlet 4, and the body 1 is provided with an intake outlet 5. A resonator connecting pipe 6 having a substantially L shape is attached to the side wall surface of the body 1 as a tubular member. The body 1, the cover 2, and the resonator connecting pipe 6 are all injection-molded using the same synthetic resin material, for example, a hard polypropylene resin. In this embodiment, when the resonator connecting pipe 6 is attached, the resonator connecting pipe 6 is rotated with respect to the body 1 in the clockwise direction. That is, in this embodiment, the clockwise direction is the first rotation direction.

  FIG. 2 shows the body 1 as a single body. As shown in the drawing, a circular mounting hole 11 is formed in a partially flat portion of the side wall portion 7 and the peripheral edge thereof is 180 °. A substantially fan-shaped notch 12 is formed in two notches. 3 and 4 show details of the vicinity of the mounting hole 11, and the periphery of the mounting hole 11 is further fan-shaped located further away from the notch 12 on the clockwise direction side of the notch 12. A main body side inclined surface 13 and a shallow concave portion 14 that is also fan-shaped and adjacent to the main body side inclined surface 13 in the clockwise direction are provided. In addition, although the said main body side inclined surface 13 and the said recessed part 14 need the same magnitude | size as an angle, in this Example, the said recessed part 14 overlaps with the said notch part 12, Therefore, Partially cut away.

  The body-side inclined surface 13 is slightly recessed with respect to the outer surface 7a of the wall portion 7 where the attachment hole 11 opens, and the height of the surface (the height in the axial direction of the attachment hole 11) is in the circumferential direction. It has an inclined surface that gradually changes along. Specifically, the end near the notch 12 is the lowest, that is, it is recessed most deeply from the outer surface 7a, the end near the recess 14 is the highest, and substantially coincides with the height of the outer surface 7a. And the said recessed part 14 is dented deeper than the edge part of this adjacent main body side inclined surface 13, Therefore The level | step difference 15 along a radial line is formed in the boundary.

  The wall 7 remains as it is between the cutout 12 and the main body-side inclined surface 13, that is, a holding portion 16 having a predetermined thickness is formed.

  Accordingly, around the mounting hole 11, a cutout portion 12, a holding portion 16, a main body side inclined surface 13, and a concave portion 14 are formed side by side in the clockwise direction. And each of these is provided at a position 180 degrees apart. Note that the direction in which the pair of notches 12 are arranged and the direction in which the pair of main body side inclined surfaces 13 are arranged are substantially orthogonal, that is, are separated from each other by about 90 °.

  Further, a second stopper portion 17 protruding from the outer surface 7 a is formed in a wall shape along the radial line of the mounting hole 11 at one place in the circumferential direction. In the illustrated example, the second stopper portion 17 is formed to be continuous with the joining flange portion 18 along the dividing surface 3 of the body 1 in a T shape (see FIG. 2), and radially outward of the main body-side inclined surface 13. Is located.

  On the other hand, as shown in FIGS. 5 to 7, the resonator connecting pipe 6 includes a cup-shaped portion 21 connected to a resonator (not shown), a tubular portion 22 bent by approximately 90 °, and a cup-shaped portion of the tubular portion 22. An annular flange portion 23 provided on the base opposite to 21 and an outer diameter extending from the flange portion 23 in the axial direction and corresponding to the inner diameter of the mounting hole 11 (strictly slightly smaller). A short cylindrical extension 24.

  The flange portion 23 has a flange surface 23a composed of a plane orthogonal to the axial direction. The diameter of the flange surface 23a (in other words, the diameter of the flange portion 23) is the cutout portion 12 on the body 1 side, the main body. The diameter is set larger than the position of the outer peripheral edge of each of the side inclined surface 13 and the recessed portion 14. The position of the second stopper portion 17 is set so as to be adjacent to the outer peripheral edge of the flange portion 23. And the 2nd stopper piece 23b which protruded to the radial direction outer side is provided in one place of the circumferential direction of the outer periphery of the flange part 23, and when this flange part 23 is rotated clockwise, this 2nd The stopper piece 23b comes into contact with the second stopper portion 17 and its rotation is restricted.

  The flange surface 23a is formed with a pair of stopper portions 25 that slightly protrude from the flange surface 23a. The stopper portion 25 has a shape complementary to the main body side inclined surface 13 recessed from the outer surface 7a on the body 1 side. Specifically, the front surface 25a having a sector shape with the same angle as the main body-side inclined surface 13 and facing the body 1 gradually increases in the circumferential direction from one end portion 25c to the other end portion 25d in the circumferential direction. (That is, the amount of protrusion from the flange surface 23a gradually increases) (see FIG. 8). Note that the amount of protrusion at the one end portion 25c is substantially zero, and continues to the flange surface 23a without a step.

  A pair of protruding pieces 26 extending in the radial direction are provided on the outer peripheral surface of the end of the extension 24. The projecting piece 26 has a substantially sector shape corresponding to the cutout portion 12 so as to be inserted through the cutout portion 12 of the mounting hole 11. Here, the positional relationship between the protruding piece 26 and the stopper portion 25 corresponds to the positional relationship between the cutout portion 12 on the body 1 side and the main body-side inclined surface 13, and a pair of protruding pieces 26 are arranged. The direction and the direction in which the pair of stopper portions 25 are arranged are substantially orthogonal.

  Further, the surface of the protruding piece 26 that faces the flange surface 23a is a second flange surface 26a that is a plane orthogonal to the axial direction, and between the flange surface 23a and the second flange surface 26a that are parallel to each other. In addition, a gap 27 having a width t slightly smaller than the thickness of the holding portion 16 is provided (see FIG. 9). As an example, the thickness of the holding portion 16 is 2.5 mm, while the width t of the gap 27 is 2.3 mm. Note that the thickness of the flange portion 23 and the thickness of the protruding piece 26 are substantially equal to the thickness of the holding portion 16. Further, as shown in FIG. 9, a part of the surface of the projection piece 26 facing the flange surface 23a forms an inclined surface as the holding portion guide surface 26b. Specifically, the holding portion guide surface 26b is provided at one end which is adjacent to the holding portion 16 when the protruding piece 26 is inserted into the cutout portion 12, and thereby, the flange portion 23a is connected to the flange portion 23a. The interval between them extends in a tapered shape so as to correspond to the thickness of the holding portion 16.

  In order to attach the resonator connecting pipe 6 configured as described above to the body 1, first, the pair of projecting pieces 26 are inserted into the mounting hole 11 so as to match the notch 12, and the flange surface 23 a is around the mounting hole 11. It is set as the state contact | abutted to the outer side surface 7a. At this time, the stopper portion 25 protruding from the flange surface 23a matches the main body-side inclined surface 13 recessed from the outer surface 7a, so that the flange surface 23a does not float from the outer surface 7a.

  Next, from this state, the entire resonator connecting pipe 6 is rotated clockwise with fingers or the like. Accordingly, the holding portion 16 enters the gap 27 between the flange surface 23a and the second flange surface 26a. Since the width t of the gap 27 is smaller than the thickness of the holding portion 16, the synthetic resin material is used. With the elastic deformation, the holding portion 16 is press-fitted into the gap 27, and the flange portion 23 strongly presses against the holding portion 16, that is, the outer surface 7 a of the wall portion 7. At this time, since the end portion of the protruding piece 26 is inclined as the holding portion guide surface 26 b, the relatively thick holding portion 16 is smoothly guided into the gap 27. On the other hand, with the rotation of the resonator connecting pipe 6, the stopper portion 25 moves to the concave portion 14 side while being in sliding contact with the main body-side inclined surface 13, and enters the concave portion 14 when it is rotated to a predetermined position. That is, the end portion 25 d of the stopper portion 25 is engaged with the step portion 15 by smoothly climbing over the step portion 15 along the main body side inclined surface 13 and fitting into the recess portion 14. Further, at substantially the same rotational position, the second stopper piece 23b of the resonator connecting pipe 6 abuts against the second stopper portion 17 on the body 1 side, and further clockwise rotation is restricted. Note that, at this rotational position, the protruding piece 26 overlaps the holding portion 16.

  Thus, in the mounting state in which the resonator connecting pipe 6 is in a predetermined angular attitude, as described above, the holding portion 16 is firmly sandwiched between the flange surface 23a and the second flange surface 26a, and the flange portion 23 Is strongly pressed against the outer surface 7a, so that the resonator connecting pipe 6 is firmly attached without causing rattling. Further, as indicated by the phantom line in FIG. 3, the flange surface 23a covers the outer peripheral side such as the cutout portion 12 and the concave portion 14 on the body 1 side. A sufficiently good sealing property can be obtained with the resin material itself.

  Then, when the stopper portion 25 is engaged with the step 15, rotation as a stopper is prevented in the counterclockwise direction, and the resonator connecting pipe 6 is prevented from loosening or dropping off due to vibration or the like.

  In addition, if the rotation is strongly counterclockwise against the engagement holding force between the stopper portion 25 and the step 15, the resonator connecting pipe 6 can be removed without being destroyed and can be reattached. It is.

  According to the above configuration, all the uneven portions necessary on the body 1 side are provided on the outer surface 7 a of the body 1, and the uneven portions are not necessary on the inner surface of the body 1. Therefore, when the body 1 is injection-molded, it is not necessary to use a complicated movable core inside the body 1, and the molding is easy.

  In the above-described embodiment, the stopper portion 25 has an inclined surface, and the main body-side inclined surface 13 is provided corresponding to the inclined surface. Therefore, the stopper portion 25 can easily move over the step 15 until it engages. And although it becomes smooth, this invention is not necessarily limited to the shape of such a stopper part. That is, it suffices if a step serving as a stopper having an appropriate shape is provided on the main body side and a stopper portion that engages with the step is provided on the tubular member side. In addition, the present invention is not limited to the above air cleaner case, and can be applied to attachment of various synthetic resin parts.

The front view of the whole air cleaner case to which this invention is applied. The front view which shows only a body. The front view which shows the structure around the attachment hole. Sectional drawing along the AA line of FIG. The side view of a resonator connection pipe. The rear view of a resonator connection pipe. Sectional drawing of a resonator connecting pipe. The principal part enlarged view seen from the arrow B direction of FIG. The enlarged view of the C section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Body 6 ... Resonator connecting pipe 11 ... Mounting hole 12 ... Notch part 13 ... Main body side inclined surface 14 ... Recessed part 15 ... Step 23 ... Flange part 23a ... Flange surface 24 ... Extension part 25 ... Stopper part 26 ... Projection piece 26a ... Second flange surface 26b ... Holding portion guide surface 27 ... Gap

Claims (4)

A synthetic resin main body having a wall portion of a predetermined thickness with a circular attachment hole opened; and a synthetic resin tubular member removably attached to the attachment hole, wherein the tubular member is first rotated. In the mounting structure of the tubular member that can be attached by rotating in the direction of rotation and removable by rotating in the direction of second rotation,
The main body
A notch formed in at least two places on the periphery of the mounting hole;
A holding portion adjacent to the cutout portion in the circumferential direction along the first rotation direction;
A step that is located a predetermined angle away from the holding portion in the first rotation direction and is recessed on the outer surface of the wall so as to serve as a stopper in the second rotation direction;
The tubular member comprises
A flange portion provided at a base portion of the tubular member and having a flange surface in close contact with a wall portion outer surface around the mounting hole;
An extension extending in the axial direction so as to enter the mounting hole from the flange,
The extension portion protrudes in the radial direction from the outer peripheral surface, has a shape that can be inserted through the notch portion, and at least two gaps that are slightly smaller than the wall thickness between the flange surface and the flange surface. A protruding piece,
An inclined surface for guiding the holding portion provided at the end of the protruding piece facing the holding portion;
A stopper portion projecting from the flange surface so that the protruding piece engages with the step at a predetermined angular position meshed with the holding portion;
An attachment structure for a tubular member, comprising:   A second stopper mechanism that is provided on the main body and the tubular member so as to come into contact with each other at a position rotated by a predetermined angle in the first rotational direction, and further includes a second stopper mechanism that restricts rotation in the first rotational direction; The mounting structure for a tubular member according to claim 1.   The tubular member mounting structure according to claim 1 or 2, wherein the stopper portion has an inclined surface in which a protruding amount from the flange surface gradually increases in the circumferential direction. It has a main body side inclined surface recessed on the main body side so as to coincide with the inclined surface of the stopper portion at an initial position where the protruding piece is inserted into the notch, and is adjacent to the main body side inclined surface. The tubular member mounting structure according to claim 3, wherein the step is formed between the concave portion and the concave portion.

Images