JPS6123450Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a suspension system for a front-engine front-wheel drive vehicle.

In front-engine front-wheel drive vehicles, there may be a difference in the length of the left and right drive shafts f and g, as shown in FIGS. 1 and 2. In Figures 1 and 2, a is the engine, b is the transmission, and c is the engine.
is the differential gear, d is the left output shaft, e is the right output shaft, h is the left king pin axis, i is the right king pin axis, j is the left wheel, k is the right wheel, m is the left suspension arm (right suspension arm), l is the lower bolt joint, A is the center plane of the vehicle body, and B is the arrow pointing forward. As shown above, the lengths of the left and right drive shafts f and g are f>
g, if there is _{a difference between them, the angles Θ L , Θ R between} the drive shaft f, g and the king pin axes h, i
Also, Q _L > Q _R. Therefore, a difference also occurs in the rotational moments M _L and M _R around the king pin axes h and i generated by the drive torque T during acceleration. That is, the rotational moment M _L on the long axis side (left drive shaft f side, which is long) is M _L = TC _ps Θ _L , and the rotation moment M _R on the short axis side (right drive shaft g side, which is short). is M _R =TC _ps Θ _R , and by Θ _L > Θ _R ,
M _L < M _R. Here _, if the rotational rigidity of the wheels around the king pin axes h and i _is CM, the steering angle of the left wheel j (φM _L is φML = CM・ML, and the steering angle of the right wheel K is φM _R = CM・_MR
Since M _L <M _R , φM _L <φM _R holds. Therefore, the handle is placed on the long axis side (hereinafter referred to as torque steer).

Conventionally, the occurrence of torque steer was prevented by reducing the difference in angles Θ _L and Θ _R between the drive shafts f and g and the king pin axes h and i as much as possible, but due to layout factors such as ground clearance and tread There is a limit to reducing the difference between the above-mentioned angles Θ _L and Θ _R , and the occurrence of torque steer cannot be sufficiently prevented. However, up until now, many front-engine front-wheel drive vehicles have been equipped with small-displacement engines, and the drive torque T was relatively small, so torque steer was within a practically acceptable range. In a vehicle equipped with a large-displacement engine, the driving torque T increases and torque steer becomes impossible to ignore.

This proposal addresses the above-mentioned problem. In a suspension system for a front-engine front-wheel drive vehicle in which the left and right drive shafts have different lengths, the height position of the connecting point between the nutcle arm and the tie rod is different between the left and right sides. The present invention relates to a suspension system characterized in that the difference in rotational moment generated around the left and right king pins is canceled out by causing different toe changes in the left and right wheels due to the power hop phenomenon during acceleration. The object is to provide an improved suspension system that can prevent torque steer even in front-engine front-wheel drive vehicles equipped with large displacement engines.

Next, the suspension system for a front-engine front-wheel drive vehicle according to the present invention will be explained using an embodiment shown in FIGS. 3 and 4. 1 is an engine, 2 is a transmission, 3
is the differential gear, 4 is the left output shaft, 5 is the right output shaft, 8 is the left drive shaft, 9 is the right drive shaft, 6 is the connection point between the left output shaft 4 and the left drive shaft 8, 7 is the right The connection point between the output shaft 5 and the right drive shaft 9, 10 and 11 are the left and right king pin axes, 12 and 13 are the left and right wheels, 16 and 1
7 is the left and right suspension arm, 14 and 15 are the inner end pivot parts of each arm 16 and 17, 18 and 19
is the lower ball joint, 20 is the rack or pinion gear shaft in the gearbox, 23, 24 are the left and right tie rods, 21, 22 are the connection points between the rack or pinion gear shaft 20 and the tie rods 23, 24, 27, 28 are the left and right tie rods. Natsukuru arm,
25 and 26 are the connection points between the nutcle arms 27 and 28 and the tie rods 23 and 24, A _L and A _R are the heights of the connection points 25 and 26, and this height is A _L > A _R
is set to .

In front-wheel drive vehicles with the above-mentioned engine, a power hop phenomenon (a phenomenon in which the front lifts up) occurs during acceleration.
As a result, the left and right wheels 12 and 13 move down relative to each other (the position change at this time is called a wheel stroke). At this time, the outer ends of the left and right tie rods 23 and 24 move in the direction of the arrow around the connection points 21 and 22, and the outer ends of the left and right suspension arms 16 and 17 move in the direction of the arrow around the inner end pivot joints 14 and 15. However, when comparing the amount of inward displacement of the outer ends of the tie rods 23 and 24 in the former and the amount of inward displacement of the outer ends of the suspension arms 16 and 17 in the latter, it is found that the suspension arms Since the tie rods 16 and 17 are more inclined with respect to the horizontal plane than the tie rods 23 and 24, the displacement of the latter is larger, and the toe of the left and right wheels 12 and 13 changes in the toe-in direction. Now, let the toe-in change of the left wheel 12 be φS _L ,
If the toe-in change of the right wheel 13 is φS _R , the height position of the connection points 25 and 26 is A _L >
A _R is set, and the toe change is φS _L > φS _R
(See Figure 5). Here, φM _R −φM _L =φ
The height positions of the connection points 25 and 26 are set so that S _L −φS _R , and the king pin axis 1
Rotational seatments M _L , M _R occurring around 0,11
That is, the difference between the steering angles φM _L and φM _R is canceled out, and the steering wheel cannot be removed.

Above, we have explained the case where the toe-in changes when the wheels are lowered, but the tie rod 23,
24 and the settings of the suspension arms 16 and 17, a toe-out change may occur when the wheel is lowered. In this case as well, connection point 2
By appropriately setting the heights A _L and A _R of the king pins 5 and 26, the difference between the rotational moments M _L and _MR generated around the king pin axes 10 and 11 can be canceled out.

[Brief explanation of the drawing]

Figure 1 is a plan view showing the suspension system of a conventional front-engine front-wheel drive vehicle, Figure 2 is its rear view, and Figure 3 is a rear view of the suspension system.
The figure is a plan view showing an embodiment of the suspension system for a front-engine front-wheel drive vehicle according to the present invention, FIG. 4 is a rear view thereof, and FIG. 5 is an explanatory diagram showing toe changes of the left and right wheels in the same suspension system. It is. 1... Engine, 8, 9... Left and right drive shafts, 10, 11... Left and right king pin axes,
12, 13... Left and right wheels, 23, 24... Left and right tie rods, 25, 26... Connection point, 27, 2
8... Left and right knuckle arms, M _L , M _R ... Rotating moment.

Claims (1)

[Scope of utility model registration request] In a suspension system for a front-engine front-wheel drive vehicle where the left and right driveshafts have different lengths, the height position of the connecting point between the knuckle arm and the tie rod is different on the left and right sides, and the power hop phenomenon during acceleration causes the left and right wheels to A suspension system characterized in that the difference in rotational moment generated around the left and right king pins is canceled out by causing different toe changes.