JP2015003542A - Vehicular suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular suspension which reduces longitudinal vibrations occurring when a vehicle passes a step without sacrificing operation stability.SOLUTION: A vehicular suspension includes: lower rods 5, each of which is connected with a pivot support member 7 holding an axle 3 and a vehicle body 4; upper rods 6, each of which is connected with the pivot support member 7 and the vehicle body 4; and an actuator 11 which moves a lower rod connection position P1 where the lower rod 5 and the pivot support member 7 are connected in a fore-and-aft direction. An upper rod connection position P2 where the upper rod 6 is connected with the pivot support member 7 is located above the lower rod connection position P1.

Description

  The present invention relates to a vehicle suspension attached to a vehicle such as a truck or a bus.

  Vehicle suspensions mounted on vehicles such as trucks and buses are required to achieve vehicle vibration reduction during travel, improved ride comfort, improved transport quality, stability during turning, improved maneuverability, etc. Yes. As such a vehicle suspension, a torque rod for determining the front-rear position of the axle is used. The torque rod is connected to the axle and the vehicle body via a torque rod bush, and normally, the rigidity of the torque rod bush is set high in order to emphasize steering stability.

JP 2008-162507 A

  However, if the torque rod bush has a high rigidity, there is a problem that the longitudinal vibration when passing through the step is not relaxed and is transmitted to the vehicle body.

  Therefore, an object of the present invention is to provide a vehicle suspension capable of reducing longitudinal vibrations when passing through a step without sacrificing steering stability.

  A vehicle suspension according to the present invention is a vehicle suspension attached to a vehicle, and includes a shaft support member for holding an axle and a lower rod connected to the vehicle body, and an upper rod connected to the shaft support member and the vehicle body. An actuator that moves the lower rod coupling position, which is the coupling position between the lower rod and the shaft support member, in the front-rear direction, and the upper rod coupling position, which is the coupling position between the upper rod and the shaft support member, is higher than the lower rod coupling position. Located above.

  According to the vehicle suspension of the present invention, since the upper rod connecting position is above the lower rod connecting position, when the lower rod connecting position is moved forward or backward by the actuator, the axle rotates around the upper rod connecting position. Move. As a result, the axle can be moved not only to the rear but also to the upper side.By driving the actuator when the wheel passes through the step, the longitudinal vibration at the time of passing through the step is sacrificed without sacrificing the steering stability. Can be reduced.

  Further, the upper rod coupling position can be the same as the lower rod coupling position or the rear of the lower rod coupling position in the vehicle longitudinal direction.

  If the lower rod coupling position and the upper rod coupling position are thus arranged, the axle can be moved rearward and upward by moving the lower rod coupling position rearward by the actuator. Thereby, when a wheel passes a level | step difference, the back-and-forth vibration at the time of a level | step difference can be reduced more effectively by moving a lower rod connection position back by an actuator.

  In addition, a road surface shape detection unit that detects a road surface shape ahead of the wheels connected to the axle, and a drive control unit that drives the actuator based on the road surface shape detected by the road surface shape detection unit are further provided. be able to.

  Thus, since the road surface shape detection unit detects the road surface shape ahead of the wheel connected to the axle, the drive control unit can predict the timing at which the step that gives the longitudinal vibration to the vehicle reaches the wheel. it can. Thereby, since the drive control part can drive an actuator in the timing which the said level | step difference reaches | attains a wheel, the longitudinal vibration at the time of the said level | step difference can be reduced appropriately.

  Further, the actuator can move the lower rod connecting position in the front-rear direction by expanding and contracting the lower rod.

  Thus, by moving the lower rod connecting position by expanding and contracting the lower rod, a conventional structure can be used as a connecting structure between the lower rod, the vehicle body, and the shaft support member, so that the cost can be reduced. .

  According to the present invention, it is possible to reduce longitudinal vibration when passing through a step without sacrificing steering stability.

1 is a plan view schematically showing a vehicle suspension according to an embodiment. 1 is a side view schematically showing a vehicle suspension according to an embodiment. It is a flowchart which shows processing operation to ECU. It is a figure which shows the operation state of the suspension for vehicles. It is a figure which shows the operation state of the suspension for vehicles. It is a figure which shows the motion of the wheel accompanying the drive of an actuator.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted. In the following description, the vertical direction means the vertical direction of the vehicle, the longitudinal direction means the longitudinal direction of the vehicle, and the inside / outside direction means the inside / outside direction of the vehicle in the vehicle width direction.

  FIG. 1 is a schematic plan view showing a vehicle suspension according to the embodiment. FIG. 2 is a schematic side view showing the vehicle suspension according to the embodiment. As shown in FIGS. 1 and 2, a vehicle suspension 1 according to the present embodiment is a multilink suspension that is attached to a vehicle such as a truck or a bus, and includes an axle 3 and a vehicle body 4 coupled to wheels 2. Between the two.

  The vehicle suspension 1 mainly includes a lower rod 5 and an upper rod 6.

  The lower rod 5 is a rod connected to the vehicle body 4 and a shaft support member 7 that rotatably holds the axle 3. The lower rod 5 is connected to the shaft support member 7 at a position below the axle 3. Here, the connection position between the lower rod 5 and the shaft support member 7 is referred to as a “lower rod connection position P1”.

  The connection of the lower rod 5 to the vehicle body 4 may be performed directly or indirectly through a member attached to the vehicle body 4 such as a bracket. FIG. 1 shows a state in which the lower rod 5 is indirectly connected to the vehicle body 4 via a bracket 4 a attached to the vehicle body 4.

  The connection of the lower rod 5 to the shaft support member 7 may be performed directly or indirectly via a member attached to the shaft support member 7 such as a bracket. FIG. 1 shows a state in which the lower rod 5 is indirectly connected to the shaft support member 7 through a support beam 7 a attached to the shaft support member 7.

  The shape of the lower rod 5 is not particularly limited, and may be, for example, a rod having a circular cross section or a plate having a rectangular cross section.

  The upper rod 6 is a rod that is disposed above the lower rod 5 and connected to the vehicle body 4 and the shaft support member 7. Here, the connection position between the upper rod 6 and the shaft support member 7 is referred to as “upper rod connection position P2”. The upper rod coupling position P2 is disposed at a position above the axle 3 and the lower rod coupling position P1. Further, the upper rod connection position P2 is disposed in the same direction as the lower rod connection position P1 or rearward of the lower rod connection position P1 in the vehicle front-rear direction.

  The connection of the upper rod 6 to the vehicle body 4 may be performed directly or indirectly via a member attached to the vehicle body 4 such as a bracket. FIG. 1 shows a state in which the upper rod 6 is indirectly connected to the vehicle body 4 via a bracket 4 b attached to the vehicle body 4.

  The connection of the upper rod 6 to the shaft support member 7 may be performed directly or indirectly through a member attached to the shaft support member 7 such as a bracket. FIG. 1 shows a state in which the upper rod 6 is indirectly connected to the shaft support member 7 via a bracket 7 b attached to the shaft support member 7.

  The shape of the upper rod 6 is not particularly limited, and can be, for example, a rod having a circular cross section or a plate having a rectangular cross section.

  The vehicle suspension 1 further includes an actuator 11, a vehicle speed meter 12, a laser displacement meter 13, and an ECU 14.

  The actuator 11 moves the lower rod connecting position P1 forward or backward. The actuator 11 can move the lower rod connecting position P1 forward or backward by extending or contracting the lower rod 5, for example. As this actuator 11, for example, a cylinder can be arranged at the center or end in the longitudinal direction of the lower rod 5, and the lower rod 5 itself can be expanded and contracted by expanding and contracting with hydraulic pressure or air pressure. .

  When the lower rod 5 extends forward from the shaft support member 7, the lower rod 5 can be moved backward by extending the lower rod 5 with the actuator 11, and the lower rod 5 can be contracted with the actuator 11. Thus, the lower rod connecting position P1 can be moved forward. On the other hand, when the lower rod 5 extends rearward from the shaft support member 7, the lower rod 5 can be moved forward by the actuator 11, and the lower rod 5 can be contracted by the actuator 11. Thus, the lower rod connecting position P1 can be moved backward.

  Here, with reference also to FIG. 6, the movement of the wheel 2 accompanying the driving of the actuator 11 will be described. FIG. 6 is a diagram showing the movement of the wheel accompanying the drive of the actuator. As shown in FIGS. 1 and 2, the lower rod 5 and the upper rod 6 are connected to a shaft support member 7.

  For this reason, when the lower rod connecting position P1 is moved rearward by the actuator 11, as shown in FIG. 6, the lower rod connecting position P1, the axle 3 and the wheel 2 rotate around the upper rod connecting position P2, Move upward. Thereafter, when the lower rod connecting position P1 is returned to the original position (initial position) by the actuator 11, the axle 3 and the wheel 2 move forward and downward to return to the original position (initial position).

  The vehicle speed meter 12 detects the vehicle speed of the vehicle. Then, the vehicle speed meter 12 transmits the detected vehicle speed to the ECU 14.

  The laser displacement meter 13 is a road surface shape detection unit that is disposed in front of the wheel 2 and detects a road surface shape in front of the wheel 2. The laser displacement meter 13 detects the distance to the road surface by detecting the reflected wave of the laser emitted toward the road surface, and detects the road surface shape by tracing the detected distance. The laser displacement meter 13 transmits the detected road surface shape to the ECU 14.

  The ECU 14 is a drive control unit that drives and controls the actuator 11 based on the detection results of the vehicle speed meter 12 and the laser displacement meter 13.

  Specifically, when the ECU 14 detects a step from the road surface shape acquired from the laser displacement meter 13, based on the detected position of the step and the distance to the wheel 2 and the vehicle speed acquired from the vehicle speed meter 12, The timing (time) at which the detected step reaches the wheel 2 is calculated (predicted). Here, the detected distance between the position of the step and the wheel 2 is a distance from the road surface position where the laser displacement meter 13 irradiates the laser to the wheel 2, and is thus determined by the installation position of the laser displacement meter 13. For this reason, the distance from the road surface position where the laser displacement meter 13 irradiates the laser to the wheel 2 is set in advance. Then, the ECU 14 drives and controls the actuator 11 at the timing when the detected step reaches the wheel 2 to move the lower rod connecting position P1 forward or backward.

  Next, with reference to FIGS. 3 to 5, the operation of the vehicle suspension 1 will be described focusing on the processing operation of the ECU 14. FIG. 3 is a flowchart showing the processing operation of the ECU. FIG. 4 is a diagram showing an operating state of the vehicle suspension. FIG. 5 is a diagram showing an operating state of the vehicle suspension.

  As shown in FIG. 3, the ECU 14 first acquires a road surface shape from the laser displacement meter 13 and detects a step from the acquired road surface shape (step S1). In step S1, at least a protruding convex step is detected.

  Next, the ECU 14 acquires the vehicle speed V from the vehicle speed meter 12, and detects the vehicle speed V when the step is detected in step S1 (step S2).

  Next, the ECU 14 detects the timing at which the step detected in step S1 reaches the wheel 2 (step S3). As described above, the distance L from the step detected in step S <b> 1 to the wheel 2 is determined by the installation position of the laser displacement meter 13. Therefore, in step S3, as shown in FIG. 4, by dividing the distance L from the step detected in step S1 to the wheel 2 by the vehicle speed V detected in step S2, the wheel 2 reaches the step detected in step S1. The timing to perform can be calculated.

  Next, when the timing calculated in step S3 arrives, the ECU 14 controls the actuator 11 (step S4).

  As shown in FIG. 5, in step S4, the actuator 11 is driven and controlled to move the lower rod connecting position P1 rearward. Then, the lower rod coupling position P1, the axle 3 and the wheel 2 rotate around the upper rod coupling position P2 and move rearward and upward. As a result, when the wheel 2 passes through the convex step, the wheel 2 is pulled up rearward and upward along the convex step, so that the longitudinal vibration during the step passage is reduced. And if the wheel 2 passes a convex level | step difference, the actuator 11 will be drive-controlled and the axle 3 and the wheel 2 will be returned to the original position by moving the lower rod connection position P1 ahead.

  The ECU 14 preferably adjusts the drive control amount of the actuator 11 according to the shape (size, inclination, etc.) of the step detected in step S1.

  As described above, according to the vehicle suspension 1 according to the present embodiment, since the upper rod coupling position P2 is above the lower rod coupling position P1, the actuator 11 moves the lower rod coupling position P1 forward or backward. Then, the axle 3 rotates about the upper rod connecting position P2. As a result, the axle 3 can be moved not only to the rear but also to the upper side. Therefore, by driving the actuator 11 when the wheel 2 passes through the step, it is possible to pass the step without sacrificing steering stability. Longitudinal vibration can be reduced.

  Further, since the upper rod connecting position P2 is the same as the lower rod connecting position P1 or behind the lower rod connecting position P1 in the vehicle front-rear direction, the axle 11 is moved rearward and backward by moving the lower rod connecting position P1 rearward by the actuator 11. It can be moved upward. As a result, when the wheel 2 passes through the convex step, the actuator 11 can move the lower rod coupling position P1 rearward to reduce the longitudinal vibration during the step passage more effectively.

  And since the laser displacement meter 13 detects the road surface shape ahead of the wheel 2, the ECU 14 can predict the timing at which the step that gives the longitudinal vibration to the vehicle reaches the wheel 2. Thereby, since the ECU 14 can drive the actuator 11 at the timing when the step reaches the wheel 2, it is possible to appropriately reduce the longitudinal vibration when the step passes.

  Further, since the actuator 11 can move the lower rod connecting position P1 by expanding and contracting the lower rod 5, a conventional connecting structure between the lower rod 5, the vehicle body 4, and the shaft support member 7 can be used. Cost can be reduced.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, the actuator has been described as moving the lower rod connecting position P1 rearward by expanding and contracting the lower rod 5, but moving the lower rod connecting position P1 rearward by moving the lower rod 5 without expanding and contracting the lower rod 5. It may be a thing.

  Further, although the road surface shape has been described as being detected by the laser displacement meter 13, it may be detected by other means such as image processing. Although the laser displacement meter has been described as detecting the road surface shape, the laser displacement meter detects only the distance to the road surface, and the ECU detects the road surface shape by tracing the detection result of the laser displacement meter. Also good. Further, the level difference may be detected not only from the road surface shape but also by a method such as detecting vibration when the front wheel passes through the level with an accelerometer attached to the vehicle. The level difference is detected by a level difference detection unit such as a laser displacement meter for detecting the road surface shape or an accelerometer for detecting the vibration of the front wheel. The ECU drives the actuator based on the level difference detected by the level difference detection unit. May be.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle suspension, 2 ... Wheel, 3 ... Axle, 4 ... Vehicle body, 4a ... Bracket, 4b ... Bracket, 5 ... Lower rod, 6 ... Upper rod, 7 ... Shaft support member, 7a ... Support beam, 7b ... Bracket, DESCRIPTION OF SYMBOLS 11 ... Actuator, 12 ... Vehicle speedometer, 13 ... Laser displacement meter (road surface shape detection part), 14 ... ECU (drive control part), P1 ... Lower rod connection position, P2 ... Upper rod connection position.

Claims (4)

A vehicle suspension attached to a vehicle,
A shaft supporting member for holding the axle and a lower rod connected to the vehicle body;
An upper rod connected to the shaft support member and the vehicle body;
An actuator for moving a lower rod connecting position, which is a connecting position of the lower rod and the shaft support member, in the front-rear direction;
With
An upper rod connection position, which is a connection position between the upper rod and the shaft support member, is located above the lower rod connection position;
Vehicle suspension. The upper rod coupling position is the same as the lower rod coupling position in the vehicle front-rear direction or is located rearward of the lower rod coupling position.
The vehicle suspension according to claim 1. A road surface shape detection unit that detects a road surface shape ahead of the wheels connected to the axle;
A drive control unit that drives the actuator based on the road surface shape detected by the road surface shape detection unit;
The vehicle suspension according to claim 1, further comprising: The actuator moves the lower rod connecting position in the front-rear direction by expanding and contracting the lower rod.
The suspension for vehicles as described in any one of Claims 1-3.

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