JP3738564B2 - Molded body having insert member for rotational torque resistance - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, in a molded product using a synthetic resin or a light alloy as a base material, the receiving member is integrally formed as an insert member so that the screw receiving portion can withstand this rotational torque when the screw member is screwed. The present invention relates to a molded body to be fixed.
[0002]
[Prior art]
Thin plate-shaped molded products such as engine oil pans are initially molded from a metal plate, and a drain plug for draining oil is provided at the bottom, which is joined to the bottom metal plate by welding or the like. Screwed into the threaded portion. However, at the present time, with the reduction in weight of engines, there are some which are manufactured with light-weight molded products using a resin such as plastic or a light alloy such as aluminum alloy or magnesium alloy as a base material.
[0003]
In this lightweight molded product, when it is necessary to increase the strength structurally, such as the screwed portion of the drain plug, the portion requiring the strength is used for reinforcing a strong material such as a steel material. This insert member is produced by press-fitting and fixing the insert member after molding, insert molding at the time of molding, or cast casting.
[0004]
Then, as shown in FIG. 5, when an insert member 10 that is a receiving member having a female screw portion is provided on the lower surface of the oil pan 40 of the engine, and a drain plug (closing member) 3 is screwed to the insert member 10. As shown in FIG. 6, the insert member 10 is formed with a cylindrical portion 11 and a polygonal flat plate-like flange portion 12 at one end thereof so as not to rotate together with the rotational torque at the time of screwing. .
[0005]
On the other hand, when such an oil pan is made of resin, it is made as thin as possible for weight reduction and the like. In particular, in the SMC (Sheet Molding Composite) method, a molding material that has been pre-impregnated with a matrix such as plastic into a fiber base material for reinforcement such as glass fiber is supplied to the mold and pressed by this mold. And it heats and shape | molds and it is set as the thin molded product as a whole.
[0006]
Therefore, when the insert member 10 is provided in the molded body 2 such as an oil pan as shown in FIG. 5, as shown in FIGS. 7, 8, and 9, a molded body body (base material) that receives the insert member 10 is used. The portion to be held on the 40 side is formed thick and is held by the ridge holding portion 42.
Then, the insert member 10 is integrally molded at the time of molding, or the insert member 10 is inserted into the through-hole 44 of the molded body 40 after being molded and engaged with the holding portion 42, and then shown in FIG. As shown, the tip of the cylindrical portion 11 is expanded in the K direction to firmly fix the insert member 10.
[0007]
When the mold is formed, the bulge holding part 42 is provided with a cavity corresponding to the bulge holding part 42 on the mold side, and the molding material melted when the sheet-shaped molding material is heated is caused to flow into the cavity. Form.
Therefore, since the reinforcing fiber base is not disposed in the thick portions 42 and 45, the connection with the thin portion 41 formed from the sheet-shaped molding material tends to be weak, and the thick portion 42 itself However, it tends to be weaker than the thin portion 41 formed of a sheet-shaped molding material.
[0008]
Accordingly, the inventors of the present invention have a polygonal concave portion 43 where the ridge portion 12 engages with the ridge holding portion 42. However, the rib 45 is formed on the radiation from the center of the concave portion 43 toward the vertex 43b. (Hereinafter referred to as a radial rib) is extended, and the radial rib 45 distributes the rotational torque applied to the bulge holding portion 42 to the peripheral thin portion 41, and the insert holding member 10 of the bulge holding portion 42 Considering ways to strengthen fixed support, we were able to achieve considerable results.
[0009]
[Problems to be solved by the invention]
However, the oil pan 40 is located at the bottom of the engine, and the drain plug 3 is further located at the bottom of the engine. Therefore, the oil pan 40 is located at the bottom of the vehicle, which is difficult to see, and is usually removed and installed using a long wrench. It is carried out. For this reason, when the drain plug 3 is removed, a strong rotational torque is often applied. The drain plug 3 may rattle while it is repeatedly tightened or loosened, and the holding portion 42 of the insert member 10 may have a radial rib 45 in particular. It is conceivable that a crack or the like occurs at the root portion.
[0010]
That is, when the polygonal insert member 10 is received by the raised holding portion 42 and the radial rib 45 is provided on the outer peripheral portion as shown in FIG. 9, the center of the polygon is formed as shown in the schematic diagram of FIG. Since the radial rib AD (45) is provided on the extension of the line connecting O and the vertex A, the force F0 generated by the rotational torque T acts in a direction perpendicular to the radial rib AD (45). The linear force Fn becomes equal to F0. Therefore, when a strong rotational torque T is applied, a large normal stress σFn is generated in the thin portion 41 holding the radial rib AD (45), resulting in a large stress value. Therefore, the radial rib AD (45) It is thought that cracks are likely to occur at the root of the slag.
[0011]
The present invention has been made to solve the above-described problems, and its purpose is to relieve stress generated in the peripheral portion of the raised holding portion on the molded body main body side that holds the insert member, and An object of the present invention is to provide a molded article having an insert member for anti-rotation torque capable of preventing damage to the peripheral portion of the raised holding portion due to the acting rotational torque.
[0012]
[Means for Solving the Problems]
A molded body having an insert member for anti-rotation torque for achieving the object as described above includes a cylindrical portion having a screw hole in the center portion and a polygonal flat plate-shaped flange portion provided at one end of the cylindrical portion. The insert member is integrally fixed to the molded product main body, and the molding member is configured to screw the closing member into the screw hole, and the outer peripheral portion of the flange portion is formed into the thick wall of the molded product main body. A rib is provided on a line extending from the outer periphery of the raised holding part and extending the sides of the polygon.
[0013]
Further, the rib is provided on a line obtained by extending the side of the polygon and in both directions of the extended line of the side.
Further, as a specific object, the molded body is an oil pan that is resin-molded by molding, and the closing member is a drain plug. In addition to this oil pan, for example, a resin tank The present invention can be applied to many parts and products having similar structures such as pipe joints and drain plugs.
[0014]
In other words, when attaching a fastening part such as a drain plug to a lightweight molded product such as resin or light alloy, the threaded screw part is reinforced with an insert member with high hardness. In order to counteract, the insert member provided with a polygonal flat plate-like collar part is fixed integrally, and moreover, not on the radiation passing through the center of the polygon in the part holding the insert member on the base material side such as resin A rib (hereinafter referred to as a side extension rib) is provided on the extension line of the side of the polygon.
[0015]
With the above configuration, it is possible to reduce the maximum value of the stress generated in the peripheral portion of the raised holding portion of the insert member on the molded body that receives the rotational torque via the insert member, and it is possible to prevent the occurrence of cracks and damage, and to reliably And a molded product with high durability and durability can be obtained.
According to the results of experiments conducted by the present inventors, in the case of a structure having side extension ribs provided on the extension of the side of the polygon, it is compared with a structure having radial ribs arranged in the radial direction of the prior art. Thus, the torque that can withstand twice the rotational torque and the resistance to destruction can be doubled.
[0016]
Below, the side extension rib provided on the extension line of the polygon side is more effectively applied to the raised holding part than the radial rib provided on the radiation passing through the center and vertex of the polygon. The fact that the torque can be distributed to the peripheral thin portions will be described with reference to the schematic diagram of FIG.
That is, when a rotational torque is generated in the insert member, a tangential force F is applied in the tangential direction of the polygonal corner portion G in the bulge holding portions 22 and 42, and this acts in the direction of expanding the side GH of the polygon. Since the radial rib 45 is provided perpendicular to the tangential force F, the radial rib 45 in the AB direction cannot be countered and has little effect.
[0017]
On the other hand, the side extension rib 25 is provided on the extension line of the side FG and can counter the component force Ft applied in the FG direction by the tangential direction force F by the side extension rib 25 on the extension CD. Further, since the side FG is pulled in the Ft direction by the tangential force Ft, the tensile force Ft can be countered by the side extension rib 26 on the extension C′D ′ of the side GF.
[0018]
On the other hand, as shown in FIG. 4, when the outer diameters of the bulge holding portions 22 and 42 are R2, and the tips of the ribs are accommodated in the same outer diameter R3, the length L1 of the radial rib (AD) 45 is set. Since L1 = R3-R2 and has the shortest length, the length L2 of the side extension ribs (CB) 25 and 26 is always larger than the length L1 of the radial rib (AD) 45.
Therefore, when the tips of the ribs are accommodated within the same outer diameter R3, the length L2 of the side extension ribs 25 and 26 is always longer than the length L1 of the radial ribs 45. Side extension ribs 25 and 26 are wider at the portion where 45 is connected. For this reason, the portion that transmits the force received by the raised holding portions 22 and 42 to the thin portions 21 and 41 becomes wider, and the rotational torque T can be distributed to the thin portions 21 and 41 by generating a smaller stress.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A molded body having an insert member for rotational torque resistance according to the present invention will be described by taking an oil pan 1 of an engine as shown in FIG. 5 as an example.
The oil pan 1 is a resin mold that integrally forms a receiving member 10 that holds a drain plug 3. The insert member 10 includes a cylindrical portion 11 and a polygonal flat plate as shown in FIG. It is formed from the collar part 12 formed in this. A screw hole 14 for mounting the drain plug 3 is provided through the center of the cylindrical portion 11 and a female screw portion 13 is provided for screwing.
[0020]
On the other hand, the base material side 20 that receives the insert member 10 is formed thicker than the plate thickness of the entire part of the oil pan 1 as shown in FIG. 1 and FIG. A protrusion holding portion 22 having a through hole 24 for inserting the portion 11 and a regular hexagonal concave portion 23 for engaging the flange portion 12 is provided, and the outer peripheral portion of the flange portion 12 is formed in the thickness of the molded product main body 20. It is configured to be surrounded by a bulge holding portion 22 formed into meat.
[0021]
Then, side extension ribs 25 and 26 are provided on a line obtained by extending the regular hexagonal side 23a of the recess 23 from the outer periphery of the ridge holding part 22 and on both sides of the extension line of the side 23a, that is, on both sides. The extension ribs 25 and 26 receive the rotational torque T received when the raised holding portion 22 receives the rotational torque T generated when the drain plug 3 as the closing member is tightened or loosened via the insert member 10. Is provided in order to disperse the force generated by
[0022]
The side extension ribs 25 and 26 are preferably provided on extension lines on both sides of the side as shown in FIGS. 1, 2 and 3B and 3C, but as shown in FIG. In addition, the apex 23b portion of the regular hexagon of the concave portion 23, that is, the side portion, can be extended only on one side in the extending direction on the side subjected to compression when the drain plug 3 is tightened, and only the extension rib 25 can be provided. Conversely, only the extension rib 26 on the opposite extension line can be provided.
[0023]
In the case of the example shown in FIG. 3C, the side extension ribs 25a and 26a extending in the Y direction are long, and the side extension ribs 25d and 26d extending in the opposite Z direction are short, depending on the location of the insert member 10. Forming.
The side extension ribs 25 and 26 may have a rectangular shape in a side view as shown in FIGS. 1 and 2, but the shape of the base material 20 with the raised holding portion 22 and the degree of engagement and appearance are taken into consideration. Then, as shown in FIG. 3 (d), a triangular shape with a taper can be formed.
[0024]
The length, height, and taper of the side extension ribs 25, 26, etc. can be determined by experiments and calculations.
In addition, the oil pan 1 is formed by supplying a molding material obtained by impregnating a matrix of plastic or the like into a fiber base material for reinforcement such as glass fiber by a SMC method to a heated mold. Molded by pressing with a mold. The insert member 10 may be integrated with the base material 20 when the oil pan 1 is molded, or may be inserted into the oil pan 1 after being molded. Further, the distal end side of the insert member 10 is expanded in the K direction as shown in FIG.
[0025]
When the drain plug 3 is screwed into the female screw portion 13 of the screw hole 14 of the insert member 10 formed integrally with the molded body 20 to close the bottom of the oil pan 1 and drain the water, The drain plug 3 is unscrewed and drained.
According to the molded body 1 having the above configuration, the raised holding portion 22 on the molded body main body 20 side is raised by the side extension ribs 25 and 26 formed on the extended line of the side 23a forming the polygonal surface of the recess 23. The force acting on the holding part 22 can be distributed to the thin part 21 in the peripheral part.
[0026]
That is, the tangential force F in the tangential direction of the polygonal corner generated by the rotational torque generated through the insert member is applied. The tangential force F is provided on the extended line of the side 12a. The side extension ribs 25 and 26 can effectively counteract. Further, since the length of the side extension ribs 25 and 26 can be increased, the connecting portion with the thin portion 21 can be widened, and the force acting on the side extension ribs 25 and 26 can be efficiently distributed to the thin portion 21.
[0027]
Therefore, since the magnitude of the stress generated in the peripheral portion of the bulge holding portion 22 that holds the insert member 10 can be reduced by the rotational torque when the drain plug 3 is tightened or loosened, the periphery due to this rotational torque is reduced. The occurrence of cracks in the part can be prevented.
According to the results of experiments conducted by the present inventors, the molded body 1 provided with side extension ribs 25 and 26 as shown in FIGS. 3C and 3D, and from the center of the regular hexagon toward the apex. As a result of comparing the torque leading to breakage with the molded body 2 provided with the radial ribs 45 provided on the extending radiation, the fracture torque of the molded body 1 provided with the side extension ribs 25, 26 is the molded body provided with the radial ribs 45. The result is about twice that of 2, and it has been experimentally confirmed that it is effective.
[0028]
In addition, instead of the side extension ribs 25 and 26, the ribs are arranged so that the regular polygons are inscribed from the outer periphery of the raised holding part 22 through the regular hexagonal apex 22b as shown in FIG. Ribs (hereinafter referred to as tangential ribs) 27 and 28 may be extended on a line that becomes a tangent line. The tangential ribs 27 and 28 may be provided only on one side as in the case of the side extension ribs 25 and 26, and the shape may be rectangular or triangular.
[0029]
【The invention's effect】
As described above, according to the molded body having an insert member for rotational torque resistance according to the present invention, an extension of the side of the polygon is formed on the raised holding portion that holds the polygonal plate-like insert member that generates the rotational torque. Since the side extension rib is extended from the outer peripheral part of the bulge holding part on the upper side, the stress caused by the rotational torque generated in the peripheral part of the bulge holding part can be reduced, and the generation and breakage of the crack can be prevented. A molded product with high reliability and durability can be obtained.
[Brief description of the drawings]
FIG. 1 is a partial perspective view including a partial cross section showing a relationship between an insert member and a molded body of a mold product according to the present invention.
FIG. 2 is a partial perspective view including a partial cross section showing a state in which the insert member of FIG. 1 is integrated with a molded body.
FIG. 3 is a schematic plan view for explaining the relationship between the side extension rib according to the present invention and the polygon of the holding portion of the insert member, and (a) is provided only on one side of the side of the polygon. (B) shows side extension ribs provided on both sides of the polygonal side, (c) shows side extension ribs provided on both sides of the polygonal side and having different lengths. ) Shows the side shape of the side extension rib part of the XX ′ part of (b), and (e) shows the tangential rib.
FIG. 4 is a schematic diagram for explaining the relationship between the acting forces when the ends of the side extension rib and the radial rib are arranged on a circle having the same diameter.
FIG. 5 is a cross-sectional view showing an example of an oil pan and an insert member.
FIGS. 6A and 6B are diagrams showing an insert member inserted into a mold generator, wherein FIG. 6A is a front view including a partial cross-sectional shape, and FIG. 6B is a plan view.
7 is a partial perspective view including a WW section showing a relationship between a prior art molded body and an insert member of FIG. 6; FIG.
8 is a partial perspective view including a WW section showing a state in which the insert member of FIG. 6 is inserted into a prior art molded body.
FIG. 9 is a schematic plan view for explaining the relationship between a prior art radial rib and a polygon of a holding portion of an insert member.
[Explanation of symbols]
1, 2 Molded body 3 Drain plug 10 Insert member
11 Cylindrical part 12 Gutter part 13 Female thread part
14 Screw hole 20 Base material 21 Thin part
22 Bump holding part 23 Recess 23a Polygon side
24 Through hole 25, 26 Side extension rib 27, 28 Tangential rib

Claims (3)

An insert member composed of a cylindrical portion having a screw hole at the center and a polygonal flat plate-shaped flange provided at one end of the cylindrical portion is integrally fixed to the molded product body, and the closing member is screwed into the screw hole. A molded body configured to fit together, wherein the outer peripheral portion of the flange portion is surrounded by a raised holding portion formed into a thick wall of the molded product body, and the polygonal side is formed from the outer periphery of the raised holding portion. A molded body having an insert member for anti-rotation torque, wherein a rib is extended on an extended line. 2. The molded body having an insert member for anti-rotation torque according to claim 1, wherein the rib is provided on a line obtained by extending the side of the polygon and in both directions of the extended line of the side. The molded body having an insert member for rotational torque resistance according to claim 1 or 2, wherein the molded body is an oil pan molded by resin molding and the closing member is a drain plug.

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