Patent Description:
In general, a vehicular suspension system is an apparatus which connects a wheel to a vehicular body. The vehicular suspension system includes a spring which absorbs vibration or impact transmitted from a road surface to a vehicular body, a shock absorber which adjusts an action of the spring, and a suspension arm or suspension link which controls an operation of the wheel.

By way of example, types of suspension systems for controlling the operation of a vehicular wheel include a swing arm type, a wishbone type, a McPherson strut type or the like. A suspension system using a wishbone type control includes a suspension arm (lower control arm) which connects a knuckle fastened to a vehicular wheel to a vehicular body. That is, one end of the suspension arm is connected to a cross member or a subframe which constitutes the vehicular body, while the other end of the suspension arm is connected to the knuckle via a ball joint. With this configuration, the suspension arm allows the vehicular wheel to be supported by the vehicular body, and appropriately controls the toe-in of the vehicular wheel in accordance with the running status of a vehicle, thereby improving the straight running performance and the steering stability of the vehicle.

The aforementioned suspension arm has been manufactured in a casting type method and a press type method. Specifically, according to the casting type method, the suspension arm is manufactured by being molded by pouring molten steel or molten aluminum into a metal mold and then solidifying the molten steel or aluminum. Further, according to the press type method, the suspension arm is manufactured by fabricating an upper plate and a lower plate from a steel plate made of a steel material by a press, and welding the upper plate and the lower plate.

However, in the aforementioned suspension arm manufacturing method, the suspension arm is fabricated from a steel casting, or the upper and lower plates are fabricated from a steel material by a press method and the upper and lower plates are welded thereafter. The foregoing methods are problematic since the weight of the suspension arm is heavy due to the characteristics of steel, a lot of manufacturing processes are required, and rigidity weakness and deformation may occur due to the welding of the steel plates. <CIT> discloses a hybrid upper arm, comprising: an upper arm body made of a metal material; and an insert injection-molded integrally with the upper arm body so that the insert is inserted into an inside of the upper arm body.

Various embodiments of the present disclosure provide a vehicular hybrid suspension arm made of a composite material to solve the problems of the steel-made or aluminum-made suspension arm and to achieve weight reduction.

Further, various embodiments of the present disclosure provide a vehicular hybrid suspension arm which can achieve increased rigidity as well as weight reduction.

According to the present invention, a hybrid upper arm as defined by claim <NUM> is provided to solve the above problems and achieve the above effects. The dependent claims show some examples of such a hybrid upper arm, which may also be as follows.

A coupling flange may be formed in the upper arm body so as to be bent inward in a width direction of the upper arm body.

The coupling flange may be inserted into and coupled to the insert.

The upper arm body may include two leg portions and a joint portion integrally connecting the two leg portions.

A bush pipe may be coupled to a leading end portion of each of the two leg portions by welding, and a ball joint pipe may be coupled to a leading end portion of the joint portion by welding.

The ball joint pipe may be located in a central portion between the bush pipes. The bush pipes may be disposed to be opened in a horizontal direction, and the ball joint pipe may be disposed to be opened in a vertical direction.

Bushes may be force-fitted into and coupled to the bush pipes respectively, and a ball joint may be force-fitted into and coupled to the ball joint pipe.

At least one hole may be formed through the upper arm body. At least one coupling protrusion, which is inserted into and fills in the at least one hole and is enlarged up to a peripheral edge of the at least one hole, may be formed in the insert.

The upper arm body may include two leg portions and a joint portion integrally connecting the two leg portions. The insert may include two leg portions and a joint portion integrally connecting the two leg portions. The at least one hole may include at least one small-diameter hole disposed in each of the two leg portions at predetermined spacings along a longitudinal direction. The at least one coupling protrusion may be inserted into and fill in the at least one small-diameter hole and may be formed in a size radially enlarged up to a peripheral edge of the at least one small-diameter hole.

The at least one small-diameter hole may include two or more small-diameter holes disposed adjacent to each other. At least one middle-diameter hole having a relatively large diameter may be formed between the two or more small-diameter holes. A portion of the insert may be inserted into the middle-diameter hole such that a middle-diameter coupling rim radially enlarged up to a peripheral edge of the middle-diameter hole is formed in the insert.

The at least one hole may include a large-diameter hole formed in the joint portion of the upper arm body. A portion of the insert may be inserted into the large-diameter hole such that a large-diameter coupling rim radially enlarged up to a peripheral edge of the large-diameter hole is formed in the insert.

At least one reinforcement rib having a lattice-patterned shape may be protrudingly formed integrally with the insert.

In the hybrid suspension arm according to one embodiment of the present disclosure, the insert made of a lightweight plastic material is integrally coupled to the suspension arm body made of a metal material. Thus, when compared with the suspension arm of a prior art which is made of a steel material or an aluminum material, the hybrid suspension arm can effectively increase overall rigidity while being relatively light weight.

Where the above-described hybrid suspension arm is applied to a vehicle, the driving stability and the durability of the vehicle can be improved due to the increase in rigidity, and improved fuel efficiency of the vehicle can be achieved due to the weight reduction.

The embodiments shown in <FIG> do not form part of the invention, but represent examples, which are useful for understanding the claimed invention.

Embodiments of the present disclosure are illustrated for the purpose of explaining the technical idea of the present disclosure.

All technical and scientific terms used in the present disclosure have the meaning generally understood by those of ordinary skill in the art to which the present disclosure pertains, unless otherwise defined. All terms used in the present disclosure are chosen for the purpose of more clearly describing the present disclosure and are not chosen to limit the scope of rights according to the present disclosure.

As used in the present disclosure, expressions such as "comprising", "including", "having", and the like are to be understood as open-ended terms having the possibility of encompassing other embodiments, unless otherwise mentioned in the phrase or sentence containing such expressions.

The singular form described in the present disclosure may include a plural meaning, unless otherwise mentioned. This applies equally to the singular form recited in the claims.

In the present disclosure, where it is mentioned in the present disclosure that one element is "connected" to another element, it is to be understood that said one element may be directly connected to said another element, or may be connected to said another element via a new additional element.

Hereinafter, descriptions are made as to embodiments of the present disclosure with reference to the accompanying drawings. In the accompanying drawings, the same or corresponding elements are denoted by the same reference numerals. In the following descriptions of the embodiments, descriptions of the same or corresponding elements may be omitted. However, even if the descriptions of elements are omitted, it is not intended that such elements are not included in a certain embodiment.

For ease of explanation, the left side in the drawings is referred to as "one side", "one end", "one end portion" or the like name, while the right side in the drawings is referred to as "the other side", "the other end", "the other end portion" or the like name.

The hybrid suspension arm described below may include a hybrid lower arm <NUM> and a hybrid upper arm <NUM>.

<FIG> is a perspective view showing a hybrid lower arm <NUM>, and <FIG> is a perspective view showing an underside of the hybrid lower arm <NUM>.

The hybrid lower arm <NUM> may include a lower arm body <NUM> which is made of a metal material such as steel or aluminum, and an insert <NUM> which is injection-molded with a plastic material and integrally coupled to the lower arm body <NUM> by injection molding.

The hybrid lower arm <NUM> may have a generally L-like shape as a whole. A ball joint <NUM> may be mounted to one end of the hybrid lower arm <NUM>, and a first bush <NUM> may be coupled to the other end of the hybrid lower arm <NUM>. A second bush <NUM> may be coupled to a corner portion between the ball joint <NUM> and the first bush <NUM>.

The ball joint <NUM> may include a cylindrical ball joint pipe <NUM>, and a ball stud <NUM> which is received in and rotatably supported by the ball joint pipe <NUM>. The ball joint <NUM> may serve to relatively rotatably connect the hybrid lower arm <NUM> to a knuckle (not shown). The first and second bushes <NUM>, <NUM> may serve to elastically connect the hybrid lower arm <NUM> to a vehicular body.

<FIG> is a perspective view of a metal material-made lower arm body <NUM> of the hybrid lower arm <NUM>.

When the lower arm body <NUM> is made of, for example, a steel material, the lower arm body <NUM> may be formed from a high tensile steel plate for a vehicle by a press method.

The lower arm body <NUM> may include a lower arm body plate <NUM> which has a generally flat plate shape, and wall flanges <NUM>, <NUM> which are generally vertically bent along edges of the lower arm body plate <NUM>.

Referring to <FIG>, one or more through holes <NUM> are formed through the lower arm body plate <NUM>, and coupling protrusions <NUM> of the insert <NUM> described below can fill in the through holes <NUM> respectively and can further protrude radially outward toward the edges of the lower arm body plate <NUM>. The through holes <NUM> and the coupling protrusions <NUM> may improve the coupling rigidity of the lower arm body <NUM> and the insert <NUM>.

The wall flanges <NUM>, <NUM> may include a first wall flange <NUM> which integrally connects from one end of the lower arm body plate <NUM> via the other end to the corner portion, and a second wall flange <NUM> which integrally connects from the corner portion to the other end. The first wall flange <NUM> and the second wall flange <NUM> may have a configuration in which they do not connect with each other.

Referring to <FIG>, the ball joint pipe <NUM> may be integrally coupled to one end of the lower arm body <NUM> by, for example, welding. A circular-arc-shaped coupling groove <NUM> for insertion of the ball joint pipe <NUM> may be formed at one end of the lower arm body plate <NUM>. In the state where the ball joint pipe <NUM> is inserted into the coupling groove <NUM>, the ball joint pipe may be coupled to the lower arm body plate <NUM> and one ends <NUM>, <NUM> of the first and second wall flanges <NUM>, <NUM> by welding.

A first bush pipe flange <NUM> may be formed at the other end of the lower arm body plate <NUM>, and the first bush <NUM> may be coupled to the first bush pipe flange <NUM> by, for example, force-fitting.

The other end <NUM> of the first wall flange <NUM> and the other end <NUM> of the second wall flange <NUM> may be formed in a generally circular arc shape at the corner portion, forming a second coupling groove <NUM>. In the state where a second bush pipe <NUM> of the second bush <NUM> is inserted into the second coupling groove <NUM>, the second bush pipe <NUM> may be coupled, by welding, to the other end <NUM> of the first wall flange <NUM>, the other end <NUM> of the second wall flange <NUM> and the lower arm body plate <NUM>.

Bent flanges <NUM>, <NUM>, which are bent toward the inside of the lower arm body <NUM>, may be formed integrally with the respective upper ends of the first wall flange <NUM> and the second wall flange <NUM>. Each of the bent flanges <NUM>, <NUM> may improve the coupling force between the lower arm body <NUM> and the insert <NUM>.

<FIG> is a perspective view of the insert <NUM> of the hybrid lower arm <NUM>, which is injected with a plastic material.

The insert <NUM> may be inserted into the inside of the lower arm body <NUM> and may be integrally coupled to the lower arm body <NUM> when the insert <NUM> is injection-molded.

The weight of the lower arm body <NUM> may have a weight ratio of <NUM>% or more (at minimum) and <NUM>% or less (at maximum) with respect to the total weight of the hybrid lower arm <NUM>.

The insert <NUM> may include: an insert body <NUM> which has a generally L-like shape as a whole and is shaped so as to correspond to the shape of the lower arm body <NUM>; first and second rim flanges <NUM>, <NUM> which are formed to extend generally vertically along a rim of the insert body <NUM> and have shapes corresponding to the first and second wall flanges <NUM>, <NUM> respectively; and a plurality of reinforcement ribs <NUM> which connect and reinforce the first and second rim flanges <NUM>, <NUM> and the insert body <NUM>.

One end of the first rim flange <NUM> and one end of the second rim flange <NUM> may be formed to surround a portion of the ball joint pipe <NUM>. The first rim flange <NUM> may be formed to surround the first bush pipe flange <NUM>. The other end of the first rim flange <NUM> and the other end of the second rim flange <NUM> may be formed so that the other end of the first rim flange and the other end of the second rim flange are coupled to a portion of the second bush pipe <NUM> in the state where they integrally connect with each other.

A plurality of the reinforcement ribs <NUM> may be formed in an intersecting manner, for example, in a lattice-patterned shape, to connect and reinforce the first and second rim flanges <NUM>, <NUM> and the insert body <NUM>. Since the insert <NUM> includes a plurality of the reinforcement ribs <NUM> as described above, the structural rigidity of the insert can increase, and the weight of the insert <NUM> can be reduced due to a plurality of empty spaces existing between the reinforcement ribs <NUM>.

<FIG> is a perspective view of a vehicular hybrid upper arm <NUM> according to an embodiment. <FIG> is an exploded perspective view of the vehicular hybrid upper arm <NUM> according to an embodiment.

The vehicular hybrid upper arm <NUM> according to an embodiment may include an upper arm body <NUM> which can be fabricated from a metal material such as steel or aluminum by a general press method. The upper arm body <NUM> may include two leg portions <NUM> and a joint portion <NUM> integrally connecting the two leg portions <NUM>.

A bush pipe <NUM> may be coupled, by welding, to each of leading end portions of the two leg portions <NUM>. A ball joint pipe <NUM> may be coupled, by welding, to a leading end portion of the joint portion <NUM>. Generally semicylindrical coupling holes may be formed at the leading end portion of each of the two leg portions <NUM> and at the leading end portion of the joint portion <NUM>. Each pipe <NUM>, <NUM> may be fitted in shape to the coupling hole and be coupled, by welding, to the coupling hole.

The ball joint pipe <NUM> may be located in a central portion between the bush pipes <NUM>. Further, the bush pipes <NUM> may be disposed to be opened in the horizontal direction, while the ball joint pipe <NUM> may be disposed to be opened in the vertical direction. Bushes <NUM> may be force-fitted into the respective two bush pipes <NUM>. The respective bushes <NUM> may be fastened to a vehicular body with a bolt or the like.

A ball joint <NUM> may be force-fitted into and coupled to the ball joint pipe <NUM>. The ball joint <NUM> may include: a ball stud <NUM>; a ball bearing <NUM> which surrounds and rotatably supports the ball stud; a dust cover <NUM> which surrounds the ball stud <NUM> to prevent intrusion of foreign matters; a ring clip <NUM> for assembling the dust cover <NUM> to the ball stud <NUM>; and a protector <NUM> covered on the ball stud <NUM>.

A large-diameter hole <NUM> having a relatively large diameter may be formed through the joint portion <NUM>. A plurality of middle-diameter holes <NUM> and a plurality of small-diameter holes <NUM>, which have a relatively small size, may be disposed in each leg portion <NUM> with predetermined spacings along a longitudinal direction of the leg portion. The middle-diameter holes <NUM> may be disposed between the small-diameter holes <NUM>. The number of the middle-diameter holes <NUM> and the small-diameter holes <NUM> may be appropriately adjusted as needed.

An insert <NUM>, which is injection-molded with a plastic material and is integrally coupled to the upper arm body <NUM> by injection molding, is provided inside the upper arm body <NUM>. A weight of the upper arm body <NUM> has a weight ratio of <NUM>% or more (at minimum) and <NUM>% or less (at maximum) with respect to the total weight of the hybrid upper arm <NUM>.

The insert <NUM> has a shape approximately similar to that of the upper arm body <NUM>. That is, the insert may include two leg portions <NUM> and a joint portion <NUM>. A large-diameter hole <NUM> may be formed through the joint portion <NUM>.

A large-diameter coupling rim <NUM>, which is enlarged in a thickness direction and a radial direction, may be formed at an edge of the large-diameter hole <NUM> of the joint portion <NUM>. The large-diameter coupling rim <NUM> may be formed to be disposed along a peripheral edge of the large-diameter hole <NUM> of the upper arm body <NUM> when the plastic insert <NUM> is injected. Thus, the large-diameter coupling rim may increases the coupling force between the upper arm body <NUM> and the insert <NUM> such that the insert <NUM> coupled to the inside of the upper arm body <NUM> is not separated from the upper arm body <NUM>.

A plurality of coupling protrusions <NUM> may be formed in each of the leg portions <NUM> of the insert <NUM> at predetermined spacings along a longitudinal direction. When the insert <NUM> is injected, each of the coupling protrusions <NUM> may be inserted into and fill in the small-diameter hole <NUM> formed in each leg portion <NUM> of the upper arm body <NUM>, and may be formed in a size radially enlarged up to a peripheral edge of the small-diameter hole <NUM>. Each of the coupling protrusions <NUM> may also improve the coupling force between the upper arm body <NUM> and the insert <NUM>.

A middle-diameter coupling rim <NUM> formed between the two coupling protrusions <NUM> may be formed so as to be radially enlarged up to a peripheral edge of the middle-diameter hole <NUM> formed in each leg portion <NUM> of the upper arm body <NUM> when the insert <NUM> is injected. Thus, the middle-diameter coupling rim <NUM> may improve the coupling force between the upper arm body <NUM> and the insert <NUM>.

<FIG> is a perspective view showing an underside of the vehicular hybrid upper arm <NUM> according to an embodiment. Referring to <FIG>, at least one reinforcement rib <NUM> is provided, which may have a generally lattice-patterned shape and may be protrudingly formed integrally with the insert <NUM>.

<FIG> is a sectional view taken along a line A-A in <FIG>. Referring to <FIG>, the upper arm body <NUM> may include two coupling flanges <NUM> which are bent inward in a width direction of the upper arm body along edges of the upper arm body.

The two coupling flanges <NUM> may be formed to face each other. The two coupling flanges <NUM> may be inserted into the inside of the insert <NUM> when the insert <NUM> is injected, thereby improving the coupling force between the upper arm body <NUM> and the insert <NUM>.

<FIG> is a graph showing maximum loads versus weights in the hybrid suspension arms according to various embodiments. The X axis represents the weights (unit: kg) of the hybrid suspension arms, and the Y axis represents the maximum loads (unit: N) which the materials of the hybrid suspension arms can withstand without being buckled.

The line labeled by "Steel" indicates a case where the suspension arm is entirely made of a steel material, and the line labeled by "'Hybrid" indicates a case where the hybrid suspension arm is comprised of two types of steel and plastic insert according to embodiments.

When using the hybrid suspension arm having a composite material of metal and plastic, the weight can be reduced in comparison with a steel-made suspension arm which can withstand the same maximum load. When the proportion of the plastic insert exceeds a certain level, i.e., when the proportion of steel is lowered, even if the total weight of the hybrid suspension arm increases, the maximum load which the hybrid suspension arm can withstand may be lowered in comparison with a general steel-made suspension arm.

Referring to the graph of <FIG>, it can be ascertained that, when the ratio of steel in the hybrid suspension arm is within <NUM>% to <NUM>% (within the range in a box) with respect to the total load at the same weights in the X axis, the maximum load of the hybrid suspension arm is higher than that of the steel-made suspension arm.

Claim 1:
A hybrid upper arm (<NUM>), comprising: an upper arm body (<NUM>) made of a metal material; and an insert (<NUM>) injection-molded integrally with the upper arm body (<NUM>) so that the insert is inserted into an inside of the upper arm body (<NUM>), the hybrid upper arm (<NUM>) is characterized in that:
the upper arm body (<NUM>) has a weight ratio of <NUM>% or more and <NUM>% or less with respect to a total weight of the hybrid upper arm,
the upper arm body (<NUM>) includes an upper wall and two side walls extending downward from the upper wall,
the insert (<NUM>) is made of a plastic material and supports the upper arm body (<NUM>),
the insert (<NUM>) includes an upper wall and two side walls extending downward from the upper wall of the insert (<NUM>),
the upper wall and the side walls of the insert (<NUM>) are coupled to the upper wall and the side walls of the upper arm body (<NUM>) respectively,
the insert (<NUM>) includes a reinforcement rib (<NUM>) having a lattice-patterned shape which is disposed in a space surrounded by the upper wall and the side walls of the insert (<NUM>) and supports the upper wall and the side walls of the insert (<NUM>),
both ends of the reinforcement rib (<NUM>) are coupled to the side walls of the insert (<NUM>) respectively and connect the side walls of the insert (<NUM>) to each other,
a vertical length of the reinforcement rib (<NUM>) is less than vertical lengths of the side walls of the insert (<NUM>), and
the reinforcement rib (<NUM>) includes: a first portion having a constant vertical length; and a second portion which is disposed between the first portion and the side walls of the insert (<NUM>) and has a vertical length gradually increasing from the first portion toward the side walls of the insert (<NUM>).