JPH08150820A - Suspension device of vehicle - Google Patents

Abstract

PURPOSE: To reduce any load to act on both upper and lower radius rods, in a vehicle with an active suspension where each hydraulic actuator is set up in front and in the rear of an axle. CONSTITUTION: Each hydraulic actuator 15 constituting an active suspension of a vehicle is set up in front and in the rear of a rear axle, and when driving torque or braking torque to this rear axle is detected, an amount of operation hydraulic pressure of these front and rear actuator 15 is increased or decreased by a controller so as to offset to torque, and any load to act on both upper and lower radius rods 6 and 7 is made up so as to be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device for a vehicle having a parallel link type passive suspension and an active suspension of a fluid pressure actuator.

[0002]

2. Description of the Related Art In a conventional parallel link type air suspension used for a rear axle of a large bus, a driving torque and a braking torque around the rear axle are supported only by an upper radius rod and a lower radius rod. In addition, since it is necessary to increase the size of the mounting brackets, the unsprung weight is increased, which adversely affects the steering stability of the vehicle. Also,
When the hydraulic actuator has an active suspension, the rod of the hydraulic actuator is twisted due to the inclination of the suspension. As a result, the friction of the hydraulic actuator increases, so that the elasticity of the suspension is not smooth and the riding comfort of the vehicle deteriorates. There was a problem.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle having a parallel link type passive suspension and an active suspension in which fluid pressure actuators are arranged in front of and behind the axle, respectively, in a driving torque and / or braking around the axle. It is to reduce the load acting on the upper radius rod and the lower radius rod by the torque.

[0004]

Therefore, a vehicle suspension device according to the present invention acts on a parallel link type passive suspension, an active suspension in which fluid pressure actuators are arranged in front of and behind the axle, and the above-mentioned axle. A detection mechanism for detecting a driving torque and / or a braking torque, and a controller for increasing / decreasing the working fluid pressure of the fluid pressure actuator in a direction of canceling the driving torque and / or the braking torque detected by the detection mechanism. ing.

[0005]

That is, since the controller controls the working fluid pressure of the fluid pressure actuators arranged before and after the axle in the direction of canceling the driving torque and / or the braking torque of the axle detected by the detection mechanism, The load acting on the upper radius rod and the lower radius rod of the parallel link type passive suspension due to the acting drive torque and / or braking torque can be reliably reduced by the operation of the fluid pressure actuator.

[0006]

Embodiments of the present invention shown in the drawings will be specifically described below. 1 to 3, a parallel link type air suspension 3 and an active suspension 4, which are passive suspensions, are provided to a rear axle tube 2 connected to a differential case 1 of a rear engine type large-sized bus, and a parallel link type air suspension. 3 is
The rear axle tube 2 includes front and rear left and right air springs 5, an upper radius rod 6 installed above the differential case 1, a lower radius rod 7 installed below the left and right sides of the differential case 1, and the like. 8
Are the left and right rear wheels.

The active suspension 4 includes a hydraulic pump 10, a main accumulator 11, an electromagnetic proportional valve 12, a pressure sensor 13, a damping valve built-in gas spring 14, and a single-acting type arranged on the front, rear, left and right of the rear axle tube 2. The hydraulic actuator 15 is composed of a hydraulic actuator 15, an oil passage 16 for sequentially connecting them, a controller 17 and the like. The hydraulic actuator 15 has an upper end attached to a side frame 18 and a lower end attached to a suspension support 19 connected to the rear axle tube 2. ing.

The controller 17 includes an up / down G sensor, a front / rear G sensor, a lateral G sensor, a load sensor, an accelerator opening sensor, an engine speed sensor, a transmission shift position sensor, a rear brake hydraulic pressure sensor, a vehicle speed sensor, and a wheel of the vehicle. Signals from the speed sensor, the pressure sensor 13 and the like are taken in, and the controller 17 uses signals such as vertical G, front-rear G, lateral G, and load of the vehicle to cause the controller 17 to rapidly accelerate or decelerate or turn the vehicle, or cause vertical displacement of the vehicle body due to road surface irregularities Alternatively, when a change in load or the like is detected, each electromagnetic proportional valve 12 is operated by a control signal from the controller 17, and the operating hydraulic pressure in each hydraulic actuator 15 is positively increased or decreased from the neutral load pressure to Active control is performed so that the running posture and vehicle height are almost constant.

For example, as shown in FIG. 4, from the initial state in which the operating hydraulic pressure in the hydraulic actuator 15 is set to the neutral load pressure, the vertical accelerations on the front, rear, left and right wheel springs are detected in step S1. The signals from the upper and lower G sensors are A / D converted, and the sprung speed is converted by integral calculation in the next step S2, and then the sprung speed of each wheel is calculated in step S3. Based on this, the sprung speed is calculated in step S4. The skyhook calculation on each wheel spring is performed, and in the next step S5, the target control oil pressure in each hydraulic actuator 15 in which the height on each wheel spring does not fluctuate is calculated, and each electromagnetic proportional according to the calculated value. Valve 1
By the operation of 2, the operating hydraulic pressure in each hydraulic actuator 15 is appropriately increased or decreased, and the running posture of the vehicle body is controlled to be substantially constant.

On the other hand, in step S6, output signals from the accelerator opening sensor, the engine speed sensor, the transmission shift position sensor, etc. are fetched, and step S6 is executed.
The drive torque T of the rear axle is calculated from these signals in 7 and output signals of the front and rear G sensor, the rear brake fluid pressure sensor, the vehicle speed sensor, the wheel speed sensor of the rear wheel 8, etc. are fetched in step S8, In step S9, the rear brake torque Q for the rear axle is calculated from these signals in consideration of the slip ratio of the rear wheel 8, and in the next step S10, the drive torque T and the rear brake torque Q are calculated.
Based on the value of, it is determined whether the vehicle is being accelerated or decelerated.

When it is determined in step S10 that the vehicle is accelerating, the process proceeds to step S11, and as shown schematically in FIG. The axial force F = T / 2d in the arrow direction commensurate with the driving torque T of the hydraulic actuator 15 is calculated, and when it is determined in step S10 that the vehicle is decelerated, the process proceeds to step S12 and the hydraulic actuator 15 Axial force commensurate with rear brake torque Q of
F = Q / 2d is calculated, and in each of the following step S13, an increase / decrease amount ± ΔP of the operating hydraulic pressure in the hydraulic actuators 15 before and after the rear axle is calculated from these axial force values, and then step S5 is entered to interrupt the rear axle. The target control hydraulic pressure or the neutral load pressure in the total of four hydraulic actuators 15 in the front, rear, left and right are corrected by the increase and decrease amounts.

Therefore, even if the drive torque T and the rear brake torque Q are applied to the rear axle, these torques are balanced by the axial force of the hydraulic actuators 15 arranged before and after the rear axle, or Since the operating hydraulic pressures of the front and rear hydraulic actuators 15 are adjusted and controlled so as to be reduced, and the loads on the upper radius rod 6 and the lower radius rod 7 are reduced,
The rods 6, 7 and their mounting brackets can be easily miniaturized as compared with the conventional one, and therefore,
The steering stability of the vehicle can be improved by reducing the unsprung weight, and at the same time, the ride comfort of the vehicle can be improved by suppressing the inclination of the suspension to reduce the friction of the hydraulic actuator 15 with respect to the rod.

Although the above embodiments relate to large buses, it goes without saying that the present invention can also be applied to large trucks and the like, and the present invention can be applied to the front axle if necessary. The air suspension may be changed to a passive suspension such as a leaf spring type suspension, and the hydraulic actuator may be replaced with a pneumatic actuator. Furthermore, regarding the fluid pressure actuators arranged before and after the axle, When the distance from the axle is different, increase or decrease the control amount of the working fluid pressure for the front and rear fluid pressure actuators,
By making it inversely proportional to the ratio of the distances, it is possible to obtain the same effects as those of the above-mentioned respective embodiments.

[0014]

In the vehicle suspension device according to the present invention, since the driving torque and / or the braking torque of the axle can be reliably reduced by the operation of the fluid pressure actuators arranged respectively in front of and behind the axle, By reducing the load acting on the provided upper radius rod and lower radius rod, it is possible to easily downsize the rod and the mounting bracket, and it is possible to improve the steering stability of the vehicle by reducing the unsprung weight, and There is an advantage that the ride comfort of the vehicle can be improved by reducing the friction of the suspension.

[Brief description of drawings]

FIG. 1 is a top view of essential parts in an embodiment of the present invention.

FIG. 2 is a side view of a main part of the above embodiment.

FIG. 3 is a main part control system diagram of the above embodiment.

FIG. 4 is a control flowchart of the above embodiment.

FIG. 5 is an explanatory view of the operation of the above embodiment.

[Explanation of symbols]

 2 Rear axle tube 3 Air suspension 4 Active suspension 5 Air spring 6 Upper radius rod 7 Lower radius rod 10 Hydraulic pump 12 Electromagnetic proportional valve 15 Hydraulic actuator 17 Controller T Drive torque Q Rear brake torque

Claims (5)

[Claims] 1. A parallel link type passive suspension, an active suspension in which fluid pressure actuators are arranged in front of and behind the axle, a detection mechanism for detecting a driving torque and / or a braking torque acting on the axle, and the detection mechanism. A vehicle suspension device comprising: a controller for increasing / decreasing a working fluid pressure of the fluid pressure actuator in a direction of canceling the detected driving torque and / or the braking torque. 2. The vehicle suspension device according to claim 1, wherein the fluid pressure actuator is a hydraulic actuator. 3. The suspension device for a vehicle according to claim 1, wherein the passive suspension is an air suspension. 4. A vehicle according to any one of claims 1 to 3, further comprising a valve which is provided in a flow path of the working fluid and which controls a working fluid pressure of the fluid pressure actuator based on an instruction from the controller. Suspension device. 5. The fluid pressure actuator according to claim 1, wherein the fluid pressure actuators are arranged at equal distances from the axle before and after the axle, and the working fluid pressures of the fluid pressure actuators are in opposite directions. The vehicle suspension system that is increased or decreased by an equal amount.