KR20010006826A - Trailing arm suspension - Google Patents

Abstract

PURPOSE: To provide a trailing arm type suspension capable of enhancing a degree of freedom of design and capable of eliminating or relieving an over- steering phenomenon at rolling time of a vehicle. CONSTITUTION: This trailing arm type suspension has a pair of trailing arms 1, an axle beam 2 and a set of brackets 3, fixedly arranged in respective lengthwise directional both end parts of the axle beam 2, and has a set of these brackets 3, connected to a pair of trailing arms 1. In this case, this trailing arm type suspension has a link member 6 for connecting the respective brackets 3 and the respective trailing arms 1, the link member 6 rotates to the front of a vehicle with a connecting point with the respective trailing arms 1 as the center at bound time of the respective trailing arms 1, and van also rotate to the rear of the vehicle around the connecting point of the center at rebounding.

Description

Trailing arm type suspension {TRAILING ARM SUSPENSION}

1. Field of invention

The present invention relates to a trailing arm type suspension used for the rear suspension of a vehicle such as an automobile. In particular, the present invention relates to a trailing arm suspension that can improve axle steering characteristics during rolling of a vehicle.

2. Description of related technology

An example of a conventional trailing arm suspension is described below with reference to FIG. 7. Further, FIGS. 8A-9B will be referred to for explaining the principle of axle steerers that may be encountered in the use of the suspension of FIG. 7.

The trailing arm suspension of FIG. 7 effectively utilizes two trailing arms 9 9A and 9B arranged in the width direction of the vehicle 8e (see FIG. 8B). Each trailing arm 9 includes a front side end 9a and a rear side end 9b. The front end 9a is pivotally connected to the body 5 of the vehicle, and the rear end 9b supports the bracket 3e attached there via two rubber bushes 82a and 82b. Thus, brackets (mounted to each trailing arm 9A, 9B) are used to fix both ends of the axle beam 2e. The axle beam 2e is hollow so that the rear axle is applied. The axle beam 2e is centered at O1, and the rubber bushes 82a and 82b are centered at O2 and O3, respectively. As shown in Fig. 7, the former center O1 is located up by a predetermined distance La from the latter centers O2 and O3.

8A and 8B, the two trailing arms 9 are generally in a horizontal position and parallel to each other when the vehicle 8e is straight ahead. On the other hand, when turning the curve, the vehicle 8e will roll as shown in Fig. 9A, so that the trailing arms 9A, 9B will cause different postures. Specifically, as shown in FIG. 7, the outer trailing arm 9B will pivot upward (or bound) relative to the vehicle body, while the inner trailing arm 9A will pivot downward (or rebound).

As described above, when the trailing arms 9A and 9B cause rotation, if the rubber bushes 82a and 82b do not cause deformation, the centers O1, O2, and O3 are O1a ', O2a', and O3a '(inner trailing). Arm 9A) or O1b ', O2b', and O3b '(outer trailing arm 9B) are assumed to move. However, this cannot be expected for the following reasons.

When the trailing arms 9 are not parallel to each other the torsional force and / or the bending force will be exerted on the axle beam 2e. However, the axle beam 2e is so hard as not to surrender to the aforementioned forces. Thus, the rubber bushes 82a, 82b supporting the axle beam 2e instead of the axle beam 2e will deform at that pressure.

As a result, when the inner trailing arm 9A rebounds (rotates downward), the centers of the rubber bushes 82a and 82b move in the direction of Na1 or Na2 from O2a 'and O3a'. Thus, as shown by arrow Nc, the center of the axle beam 2e (exactly, the center of the inner end of the axle beam 2e) moves in an arc around the instantaneous center O4 from the position O1a 'to the position O1a ".

Similarly, when the outer trailing arm 9B is bound (rotating upward), the center 82a, 82b of the rubber bush is moved in the direction of Nb1 or Nb 'from O2b' and O3b '. Thus, as indicated by arrow Nd, the center of the axle beam 2e (exactly, the center of the outer end of the axle beam 2e) moves in an arc around the instantaneous center O5 from the position of O1b 'to O2b ".

As described above, when the two trailing arms 9A, 9B are rotated vertically, the center of the inner end of the axle beam 2e moves forward as indicated by arrow Nc, while the outer center of the axle beam 2e moves to the arrow Nd. Move back as indicated. Thus, as shown in the longitudinal direction of the vehicle, the inner end of the axle beam 2e is located in front of the outer end by some length Sa.

As a result, when the vehicle 8e is moving on the curve, as shown in Fig. 9B, the rear wheels Wc and Wd are directed out of the curve, which means generation of an axle steer. The axle steer described makes the vehicle 8e turn faster than the driver predicted (over-steer), which is undesirable in terms of vehicle safety and driveability.

The applicant of the present application discloses a means of preventing over-steering in Japanese JP-A-9-323518.

According to the conventional prevention means, when applied to the apparatus as shown in Fig. 7, the centers O2 and O3 of the rubber bushes 82a and 82b are disposed above the center O1 of the axle beam 2e. By doing so, the center of the inner end of the axle beam 2e can move backwards (when the inner trailing arm 9A rebounds), while the center of the outer end of the axle beam 2e can move forward (outer trailing arms When 9B is bound). In this way, an Under Steer will be achieved.

According to the conventional preventive means described above, however, the trailing arm needs to be disposed on the axle beam. In this way, only an excessively limited area should be left for the mounting of the suspension springs. In addition, there is a drawback in that the suspension stroke cannot be made sufficiently long.

SUMMARY OF THE INVENTION The present invention has been presented because of the above-described circumstances, and an object thereof is to provide a trailing arm suspension that permits various construction devices and can at least overcome or reduce oversteer that occurs when the vehicle rolls.

According to the present invention, there is provided a trailing arm suspension having the following configuration. The trailing arm suspension comprises at least one trailing arm pivotally connected to the vehicle body at the front end; The axle beam extends in the width direction to traverse the trailing end of the trailing arm; The bracket is mounted at the end of the axle beam;

In addition, it comprises a link for connecting the bracket to the trailing arm, which link can rotate about the bracket about the first axis and also rotate about the trailing arm about the second axis. Characterized by the ability to

And when the trailing arm is bound so that the link can pivot in the forward direction of the vehicle about the second axis, while the trailing arm is in the rearward direction of the vehicle about the second axis when the trailing arm is bound Characterized in that arranged to rotate.

By doing so, the outer end of the axle beam will be located in front of the inner end of the axle beam when the vehicle turns (rounding the curve). This achieves the desired understeer, which advantageously improves the maneuverability and stability of the vehicle.

According to the invention, the axle beam can be arranged above or below the trailing arm for the benefit of the understeer described above. Thus, the degree of freedom in designing the vehicle amount is improved.

According to a preferred embodiment, the trailing arm suspension comprises a first rubber bush. In that case, the bracket is connected via a link with the first rubber bush to the trailing arm.

By doing so, when a horizontal external force is applied to the axle beam, most of the load is not burdened by the link but by the first rubber bush. From this point of view, it is preferable that the rubber portion of the first bush is made soft, so that the driving of the vehicle is comfortable. The plurality of soft rubber bushes supporting the brackets must point out that the overall suspension compliance of the suspension may be too large in that way, leading to uncomfortable driving. According to the device of the present invention such a problem does not occur.

The trailing arm suspension is preferably constructed such that the spring constant of the second and third rubber bushes is greater than the spring constant of the first rubber bush. In this case, the link is connected to the trailing arm via the third bush, while the link is connected to the bracket via the third rubber bush. Instead of the second and third rubber bushes, ball joints are also possible. It is preferable that the center of the first axis and the axle beam, which are the centers of the first rubber bush, be essentially the same height at the time of non-bounding or at the time of non-rebounding. The trailing arm suspension preferably comprises a shock absorber connected thereto. Further, the first rubber bush includes a rubber member that is easier to deform in the horizontal direction than in the vertical direction.

According to a preferred embodiment, the rubber member forms a hole arranged horizontally.

The trailing arm suspension preferably constitutes a fourth rubber bush in order to connect the shock absorber to the trailing arm.

When the first axis is in a neutral state where the trailing arm is non-bound and non-bound, the first axis is preferably located in front of the second axis in the forward direction of the vehicle.

According to a preferred embodiment, the bracket comprises a front member and a rear member fixed to (eg welded to) the axle beam. Optionally, these two members may be formed in one body.

The trailing arm suspension can be further configured with an additional trailing arm similar to the trailing arm and the device, spaced at the same distance from the trailing arm posted in the width direction of the vehicle.

Other functions and conveniences of the present invention will become apparent from the following detailed description with reference to the accompanying drawings.

1 is a schematic plan view of a trailing arm suspension according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

FIG. 3 is a perspective view of main parts of the trailing arm suspension shown in FIG. 1. FIG.

4 is a view for explaining the function of the trailing arm suspension.

Fig. 5A is a schematic side view showing the vehicle when the vehicle equipped with the trailing arm suspension of the present invention is turned.

5B is a plan view showing the direction of orientation of the wheel.

6 is a side view partially showing a cross-section of the main part according to the second embodiment of the present invention.

7 illustrates the function of a conventional trailing arm suspension.

8A is a schematic side view showing the vehicle in a straight state.

8B is a plan view showing the direction in which the wheels are directed.

9A is a side view schematically showing the vehicle running in an oversteer state.

9B is a plan view showing an oversteer state.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Reference is first made to FIGS. 1-3 illustrating a trailing arm suspension according to a first embodiment of the present invention. Through this figure, the arrow Fr indicates the forward direction (length direction) of the vehicle, the double-headed arrow W indicates the width direction of the vehicle, and the arrow Up indicates the upward direction of the vehicle.

As shown in FIG. 1, the trailing arm suspension of the present invention has a pair of trailing arms 1 (1A, 1B), axle beams 2 and a pair of brackets 3 attached to both ends of the axle beam, respectively. Other components will be described later.

The trailing arms 1A and 1B are separated from each other by a predetermined distance W in the width direction, and extend in the longitudinal direction Fr. Each trailing arm 1 has a front end 10 connected to the body 5 by a shaft 50. The trailing arms 1A and 1B can thus be rotated perpendicular to each shaft 50. Although not shown, a rubber bush is used to connect the front end 10 of the trailing arm 1 to the body 5. The axle beam 2 is of tubular (ie hollow) configuration, whereby the axle 20 for the rear wheels can be accommodated. The end of the axle beam 2 extends in the widthwise W direction across the trailing arms 1A, 1B. Axle 20 is the drive shaft. Thus, the axle beam 20 is formed of a housing part 21 composed of a deceleration mechanism coupled to the axle 20 at the center in the longitudinal direction. Of course, the present invention is not limited to this example, and the axle 20 may be a driven shaft.

As shown in Figs. 2 and 3, each bracket 3 is made of a metal plate and fixed to the axle beam 2 by welding, for example. In the described embodiment, the bracket 3 consists of the pressing member 3a and the rear member 3b separated by the axle beam 2. However, these members 3a and 3b can also be integrated into one body.

In the use of the embodiment of the trailing arm suspension described, an important feature consists of a linkage mechanism for connecting the bracket 3 to the rear end of the trailing arm 1. In essence, the front member 3a of the bracket 3 is connected to the trailing arm 1 by a rubber bush 4 (first rubber bush) and the rear member 3b of the bracket 3 is joined to the trailing arm 1 by a link 6. The link 6 is connected by the rear member 3b and the 2nd rubber bush 7A, and is also connected with the trailing arm 1 by the 3rd rubber bush 7B.

The first rubber bush 4 is an ordinary component including inner and outer members 40 and 41 made of cylindrical metal, and the rubber member 42 is disposed between these metal members.

This shape also has second and third rubber bushes 7A and 7B. However, it should be noted that the rubber member 42 of the first rubber bush 4 has a spring constant smaller than the second and third rubber bushes 7A and 7B. Thus, the rubber member 42 of the first rubber bush 4 is less hard than the rubber members of the second and third rubber bushes 7A, 7B.

In the rubber member 42 of the first rubber bush 4, two holes 42a are formed and arranged before and after the inner member 41. Thus, the rubber member 42 deforms better in the horizontal direction (the longitudinal direction of the vehicle) than in the vertical direction. Hole 42a is a through hole. Instead, it may be a bottomed groove. In the latter case, additionally a groove can likewise be formed on the other side of the rubber member 42 (not illustrated). The outer member 40 of the first rubber bush 4 is fixed to the trailing arm 1, for example by welding. The inner member 41 is fixed to the front member 3a of the bracket 3 by fastening means such as bolts (see FIG. 3). In this way, the first rubber bush 4 is connected to both the trailing arm 1 and the bracket 3.

Link 6 is made of metal and has a predetermined length. The upper end of the link 6 is fixed to the outer cylinder member of the second rubber bush 7A, for example by welding. The inner cylinder member of the second rubber bush 7A is fixed to the rear member 3b of the bracket 3 by fixing means 70 such as a bolt (see FIG. 3). The outer cylinder member of the third rubber bush 7B is fixed to the trailing arm 1, for example by welding. The inner cylinder member of the third rubber bush 7B is fixed by fixing means 71 such as a bolt at the lower end of the link 6.

As shown in FIG. 2, when the trailing arm 1 takes a neutral position (ie when there is no bound or rebound), the center Oa of the fixing means 43 of the first rubber bush 4, the center Ob of the axle beam 2 and the first 2 The center Oc of the fixing means 70 of the rubber bush 7A is (in fact) the same height, so that the three centers are located (or adjacent) on the horizontal line C.

When the trailing arm 1 is in the neutral position, the link 6 is in a forward tilted position as shown in FIG. 2, and the center Oc of the fixing means 70 is equal to the center Od of the fixing means 71 by a preset distance. It is located in front of it. In other words, a predetermined angle θ is achieved between the straight line C1 through the centers Oc, Od and the horizontal line. With the existing angle θ, the link 6 is allowed to rotate in the longitudinal direction, as will be described later.

As shown in FIGS. 2 and 3, a fourth rubber bush 79 is attached to the trailing end of each trailing arm 1. The fourth rubber bush 79 is connected to the lower end of the shock absorber 59. Although not shown, the upper end of the shock absorber is connected to the vehicle body 5.

Referring to Fig. 4, the function of the trailing arm suspension having the above configuration will be described below.

When the vehicle rolls along the curve, the outer trailing arm 1B is bound in the N1 direction, as indicated by the dashed-dotted line. In this case, on the principle as already explained with reference to Fig. 7, an external force is applied to the fixing means 70 of the second rubber bush 7A, and the fixing means 70 is forced in the N2 direction (down and up). As a result, the link 6 causes a forward rotation (counterclockwise in FIG. 4) about the fastening means 71, and simultaneously pushes the bracket 3 forward Fr. The front member 3a of the bracket 3 is supported by the first rubber bush 4, but the deformed rubber member 42 of the first bush 4 allows the bracket 3 (and fixing means) to displace. In this way, the center Ob of the axle beam 2 is advanced to the position Ob ', as shown by the arrow N3.

More strictly speaking, the fastening means 43 of the first rubber bush 4 under the bounding of the trailing arm 1 is subjected to the upward force indicated by arrow N4. As a result, the center Ob of the axle beam 2 is advanced near Oe, and the position Oe is the instantaneous center defined by the displacements represented by N2 and N4. In this respect, the instantaneous center Oe of the present invention is located above the center Ob of the axle beam 2, and the instantaneous center of the axle beam is as opposed to the conventional technique set below the axle beam, as shown in FIG. Should be recognized.

Referring again to FIG. 4, when the inner trailing arm 1A rebounds in the N5 direction, the fixing means 70 of the second rubber bush 7A is subjected to an external force as indicated by arrow N6, and the force is applied to the fixing means 70. Force upward and backward movement. Thus, the link 6 is caused to rotate rearward (clockwise in FIG. 4) about the fixing means 71 and drag the bracket 3 also to the rear of the vehicle against the restoring force of the rubber member of the first rubber bush 4. On the other hand, in this rebound, the fixing means of the first rubber bush 4 is subjected to the downward force shown by arrow N8. As a result, the center Ob of the axle beam 2 is displaced to the rear of the vehicle, as indicated by the arrow N7, and reaches the position Ob " near the instantaneous center Of defined by the movement operation on the N6 and N8. In this case, the instantaneous center Of is located above the center Ob of the axle beam 2.

Referring to FIGS. 5A and 5B with the trailing arm suspension described above, the outer end 20b of the axle beam 2 (bounding side) is forward relative to the inner end 20a (rebounding side) when the vehicle 8 turns in the N9 direction. Is placed. This means that understeering is achieved by rear wheels Wa and Wb directed on the inside of the curve. In this state, the safety and maneuverability of the vehicle are usefully improved.

Another advantage of the trailing arm suspension of the present invention is that a large space is secured above the axle beam 2 since the trailing arms 1A and 1B are arranged below the axle beam 2. This allows the attachment of a suspension spring on top of the axle beam 2, while at the same time allowing the trailing arms 1A, 1B to rotate at a sufficient angle.

Furthermore, according to the trailing arm suspension, the link 6 can rotate more easily while reducing the angle θ described with reference to FIG. 2. This means that by reducing the angle θ, the vehicle can more easily trigger a roll. In this way, the rolling characteristics of the vehicle can be adjusted by simply changing the angle θ, thereby facilitating vehicle design.

The trailing arm suspension of the present invention is advantageous because the driver (and passengers) can feel comfortable when driving straight (normal driving conditions). According to the arrangement shown in FIG. 2, most of the horizontal force acting on the axle beam 2 is exerted on the first rubber bush 4, which is harder than the second and third rubber bushes 7A, 7B (with a smaller spring constant). Do. In this way, unlike the case where a plurality of relatively soft bushes are used, the vibration shock of the suspension system can be prevented from being excessively high.

Moreover, when the vehicle is in a normal driving condition, the center Oa of the fixing means 43 of the first rubber bush 4, the center Ob of the axle beam 2 and the center Oc of the fixing means 70 of the second rubber bush 7A are on the same horizontal line (see FIG. 2). It is arranged on). Thus, the horizontal force acting on the axle beam 2 does not generate a moment about the axle beam 2. Therefore, even if a horizontal external force is applied to the vehicle, it is possible to prevent or at least reduce sudden swing of the vehicle body.

As described above, the first rubber bush 4 has a relatively small spring constant in the longitudinal direction of the vehicle and a relatively large spring constant in the vertical direction. Thus, the first rubber bush 4 serves as an excellent buffer in the horizontal direction while not in the vertical direction. Therefore, when a vertical force is applied to the axle beam 2, this force is actually absorbed directly by the buffer 59. According to the present invention, in this way, the shock absorber 59 is effectively used, thereby contributing to a comfortable running against the vertical external force acting on the vehicle.

When the vehicle rides over the protrusions on the road, vertical and horizontal forces are simultaneously applied to the vehicle wheel and axle beam 2. However, as described above, by using the trailing arm suspension of the present invention, two undesirable forces are absorbed. In this way, the driver can enjoy a comfortable driving.

Referring to FIG. 7 while describing important parts of the trailing arm suspension according to the second embodiment of the present invention.

In a second embodiment, the axle beam 2 'is arranged under the trailing arm 1'. Moreover, the first rubber bush 4 'is located behind the axle beam 2' and the link 6 'is arranged in front of the axle beam 2'.

In such an arrangement, when the trailing arm 1 'is bound, the link 6' pivots forward about the fixing means 71 'of the third rubber bush 7B', thereby moving the axle beam 2 'towards the front of the vehicle. . On the other hand, when the trailing arm 1 'rebounds, the link 6' is caused to pivot backward about the fixing means 71 ', thereby moving the axle beam 2 to the rear of the vehicle. Thus, understeer operation is also performed in the second embodiment as in the first embodiment described above.

As fully described above, according to the present invention, the understeer is made not only when the axle beam is disposed above the trailing arm but also when the axle beam is disposed below the trailing arm.

It should be noted that the present invention is not limited to the above-described embodiment. For example, a ball joint may be used instead of a rubber bush to connect the link to the bracket or trailing arm.

.

Claims (10)

At least one trailing arm 1, 1 ′ and its front end are pivotally connected to body 5; The axle beams 2, 2 ′ cross the trailing end of the trailing arms 1, 1 ′ in the width direction of the vehicle; As brackets 3, 3 'are fixed to the ends of the axle beams 2, 2'; Links 6 and 6 'are formed for connecting brackets 3 and 3' to the trailing arms 1 and 1 ', with links 6 and 6' centering around the first axis Oc. It can be rotated relative to the bracket (3, 3 ') and also rotated relative to the trailing arms (1, 1') around the second axis (Od), When the trailing arms 1, 1 'are bounded, the links 6, 6' are rotated in the forward direction Fr of the vehicle about the second axis Od and at the same time the trailing arms 1 Trailing arm suspension, characterized in that 1 ') rotates in the rearward direction of the vehicle about the second axis Od when rebounding. The first rubber bush 4, 4 'constitutes a trailing arm 1, 1 by means of the first rubber bush 4, 4' and the link 6, 6 'with brackets 3, 3'. The trailing arm suspension according to claim 1 connected to '). Constituting the second and third rubber bushes 7A, 7A '; 7B, 7B', the spring constant of which is greater than the spring constant of the first rubber bush 4, 4 ', where the links 6, 6' ) Is connected to the brackets 3, 3 'by the second rubber bushes 7A, 7A' and at the same time by the third rubber bushes 7B, 7B 'to the trailing arms 1, 1'. Linked trailing arm suspension according to claim 2. The first axis Oc, the center Oa of the first rubber bush 4, 4 ′ and the center Ob of the axle beams 2, 2 ′ have the trailing arms 1, 1 ′ unbounded, The trailing arm suspension according to claim 2 or 3, which is generally at the same height when in a non-rebound neutral state. The trail of claim 2 or 3 comprising a shock absorber 59 connected to the trailing arm 1, wherein the first rubber bush 4 consists of a rubber member 42 which is more deformed in the horizontal direction than in the vertical direction. Ring arm suspension. The rubber member 42 is a trailing arm suspension according to claim 5, wherein the holes 42a are formed horizontally. The trailing arm type suspension according to claim 5 or 6, which is composed of a fourth rubber bush 79 for connecting the shock absorber 59 to the trailing arm 1. When the trailing arms 1, 1 'are non-bounding and non-rebounding in neutral, the first axis Oc is located in front of the second axis Od in the direction of the front of the vehicle (Fr). The trailing arm type suspension according to claim 3. The trailing arm according to any one of claims 1 to 3, wherein the brackets 3, 3 'comprise a front member 3a and a rear member 3b, both of which are fixed to the axle beams 2, 2'. Expression suspension. Additional trailing arms 1B, 1B ', similar in arrangement to the above-described trailing arms 1, 1', at regular intervals in the width direction of the vehicle with the aforementioned trailing arms 1, 1 '. The trailing arm type suspension according to any one of claims 1 to 3 comprising a.