JP2020050223A - Air suspension system - Google Patents

Abstract

To prevent deformation of a lever to which a sensor is attached.SOLUTION: An air suspension system includes: an air suspension provided between a vehicle body frame 11 and an axle; a lever 3 which is swingably attached to the vehicle body frame 11; a rod 4 which is swingably attached to the axle and the lever 3; and a sensor 5 which is attached to the lever 3 and detects a vehicle height based on an inclination of the lever 3. The lever 3 has a cutout 3c which opens upward at an attachment position of the rod 4 and has a substantially U shape.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an air suspension system including a sensor that detects a vehicle height based on a tilt of a lever.

  Conventionally, an air suspension system that adjusts a vehicle height using an air suspension (air spring) is known. In the air suspension system, the air pressure of the air suspension is adjusted according to the vehicle height detected by a sensor (height sensor) mounted on the vehicle (for example, see Patent Document 1). Generally, the sensor is attached to a lever provided so that the inclination changes according to the vehicle height, and is configured to detect the vehicle height based on the inclination of the lever.

JP 2001-047836 A

  By the way, in a cold region, for example, a lump of ice may be formed at a position above the lever described above. If the vehicle height is reduced in a state where the ice blocks are formed, the ice blocks may come into contact with the lever from above and apply a downward load to the lever. As a result, when the lever is deformed into a bent state, the inclination of the lever does not correspond to the actual vehicle height, so even if the air pressure of the air suspension is adjusted according to the detection value of the sensor, the vehicle height is not appropriately changed. The problem may arise.

  The air suspension system of the present invention has been made in view of the above-described problem, and has as one object to prevent deformation of a lever to which a sensor is attached.

  The air suspension system disclosed herein includes an air suspension provided between a body frame and an axle, a lever swingably mounted on the body frame, and a swingably mounted on the axle and the lever. And a sensor attached to the lever and detecting a vehicle height based on the inclination of the lever, the lever having a substantially U-shape opened upward at the mounting position of the rod. It is characterized by having a notch.

  In this manner, by forming a substantially U-shaped notch opened upward at the rod mounting position on the lever, the lever can be moved downward when a downward load is input to the lever. Move from the rod, and the concentration of stress in the lever is suppressed.

  According to the disclosed air suspension system, deformation of the lever to which the sensor is attached can be prevented.

1 is a schematic side view of a rear portion of a vehicle to which an air suspension system according to an embodiment is applied. It is a figure similar to FIG. 1, (A) has shown the state which raised the vehicle height, and (B) has shown the state which lowered the vehicle height. FIG. 2 is an enlarged view of a main part of a lever applied to the air suspension system of FIG. 1. FIG. 4 is a diagram in which a rod is combined with a cross section taken along the line AA in FIG. 3. 2A and 2B are schematic diagrams illustrating the operation of the air suspension of FIG. 1, wherein FIG. 1A illustrates a state before the vehicle height is reduced, FIG. 2B illustrates a state where the vehicle height is reduced, and FIG. It shows a state where it has come off.

  An air suspension system as an embodiment will be described with reference to the drawings. The embodiment described below is merely an example, and there is no intention to exclude various modifications and application of technology not explicitly described in the following embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. Further, they can be selected as needed, or can be appropriately combined.

[1. Constitution]
The air suspension system 1 of the present embodiment is applied to a vehicle 10 shown in FIG. The vehicle 10 is, for example, a truck in which a packing box is provided above a ladder-shaped body frame. Here, the direction in which gravity acts is defined as a downward direction, and the opposite direction is defined as an upward direction.

  The body frame of the vehicle 10 includes a pair of side frames 11 extending in the front-rear direction (vehicle length direction) D. The pair of side frames 11 are spaced apart from each other in the left-right direction (vehicle width direction). A rear axle (axle) 13 that supports a rear wheel (wheel) 12 is disposed below the side frame 11. The rear shaft 13 extends in the left-right direction, and is rotatably housed in a cylindrical axle housing 14.

  In the present embodiment, an air suspension system 1 applied to a rear wheel 12 will be exemplified. The air suspension system 1 has a function of reducing the impact force input from the rear wheel 12 to the side frame 11 and a function of changing the vehicle height (the height of the vehicle 10). The air suspension system 1 includes an air suspension 2 configured so that the internal air pressure can be adjusted, a lever 3 and a rod 4 provided to swing according to the vehicle height, and a vehicle height based on the inclination of the lever 3. And a sensor 5 for detecting the

  The air suspension system 1 of the present embodiment further includes a shock absorber 6 that attenuates vibration transmitted from the rear wheel 12 to the side frame 11. These members 2 to 6 of the air suspension system 1 are arranged on the left and right of the vehicle 10 respectively. In the present embodiment, it is assumed that the air suspension system 1 is configured symmetrically.

  The air suspension 2 is an air spring (buffer) that absorbs vibration and impact transmitted from the rear wheel 12 to the side frame 11 by using the elastic force (compression force) of air. In the present embodiment, a case where a pair of air suspensions 2 is provided for one rear wheel 12 will be exemplified. The pair of air suspensions 2 are arranged apart from each other in the front-rear direction D, and are respectively located in front of and behind the rear shaft 13.

  The lower ends of the pair of air suspensions 2 are connected to each other by a support beam 16 extending in the front-rear direction D and fixed to the lower surface of the axle housing 14. That is, the lower end of each air suspension 2 is attached to the rear shaft 13 via the support beam 16 and the axle housing 14. The upper end of each air suspension 2 is attached to the side frame 11 via a bracket 21. As described above, each air suspension 2 is provided between the side frame 11 and the rear shaft 13, and has a lower end attached to the rear shaft 13 and an upper end attached to the side frame 11.

  The internal air pressure of each air suspension 2 is changed according to the amount of air supplied from an air tank (not shown). The air pressure of the air suspension 2 is controlled by a control device (ECU) 15 mounted on the vehicle 10. Each air suspension 2 expands in the vertical direction when the internal air pressure increases, and contracts in the vertical direction when the internal air pressure decreases.

  When the air suspension 2 expands in the up-down direction, the side frame 11 is lifted away from the rear shaft 13, so that the vehicle height increases. Conversely, when the air suspension 2 withers in the up-down direction, the side frame 11 is lowered so as to approach the rear shaft 13, so that the vehicle height decreases. As described above, since the vehicle height of the vehicle 10 changes according to the air pressure of the air suspension 2, the air suspension 2 is also used for adjusting the vehicle height.

  The lever 3 is, for example, an elongated plate-shaped member. One end 3 a of the lever 3 is swingably attached to the side frame 11, and the other end 3 b is connected to the rod 4. Hereinafter, the one end 3a of the lever 3 is also referred to as “lever base end 3a”, and the other end 3b of the lever 3 is also referred to as “lever distal end 3b”. The detailed structure of the lever 3 will be described later.

  The rod 4 is, for example, a round bar-shaped member. One end 4 a of the rod 4 is swingably attached to the rear shaft 13 via a bracket 41 fixed to the upper surface of the axle housing 14 and the axle housing 14. The portion 4b is swingably attached to the lever tip 3b. Hereinafter, the one end 4a of the rod 4 is also referred to as a “rod base end 4a”, and the other end 4b of the rod 4 is also referred to as a “rod tip 4b”. The connection structure between the lever 3 and the rod 4 will be described later.

  When the lever 3 and the rod 4 are connected to each other at the lever tip 3b and the rod tip 4b, the lever 3 is located above the rod 4. In this state, the lever 3 and the rod 4 form a V-shape when the vehicle 10 is viewed from the side. When the vehicle height changes according to the air pressure of the air suspension 2, the relative position of the lever base end portion 3a and the rod base end portion 4a changes as the height position of the side frame 11 with respect to the axle 13 changes. As a result, each posture of the lever 3 and the rod 4 changes, and the V-shape formed by the lever 3 and the rod 4 also changes.

  The lever 3 of the present embodiment is configured so that its inclination changes according to the vehicle height. As shown in FIGS. 2A and 2B, the “tilt” of the lever 3 as used herein refers to the connection between the lever base end 3 a and the lever distal end 3 b in a side view of the vehicle 10 (ie, the lever 3). 3 (extending in the longitudinal direction) of the virtual straight line L. In the present embodiment, an angle (acute angle) θ formed by a straight line L with respect to a horizontal line H extending in the front-rear direction D and passing through the lever base end 3a in a side view of the vehicle 10 is defined as the inclination of the lever 3.

  When the vehicle height rises as shown in FIG. 2A, the lever 3 swings downward (counterclockwise in FIG. 2A) about the lever base end 3a. When the vehicle height decreases as shown in FIG. 2B, the lever 3 swings upward (clockwise in FIG. 2B) about the lever base end 3a. In the present embodiment, the direction of increase and decrease of the angle θ is determined assuming that the angle θ increases when the lever 3 swings downward (θ +) and the angle θ decreases when the lever 3 swings upward (θ−).

  The sensor 5 is a height sensor that detects the inclination of the lever 3 and detects the vehicle height based on the detected inclination. The sensor 5 of the present embodiment is attached to the lever base end 3a. The sensor 5 transmits the detected vehicle height to the control device 15.

  The shock absorber 6 has an upper end attached to the side frame 11 via a bracket 61, and a lower end attached to the support beam 16 via a bracket 62.

  The control device 15 compares the vehicle height (detected value) detected by the sensor 5 with a target value, and controls the air pressure of the air suspension 2 based on the difference between the detected value and the target value. More specifically, when the detected value is smaller than the target value, control device 15 increases the air pressure of air suspension 2 so that the vehicle height increases. Conversely, when the detected value is larger than the target value, control device 15 reduces the air pressure of air suspension 2 so that the vehicle height decreases. Such control of the vehicle height is performed when the vehicle 10 is stopped and when the difference between the detected value and the target value does not fluctuate for a predetermined time (for example, one minute) while the vehicle 10 is running. You. The target value of the vehicle height may be a fixed value that is set in advance, or may be a variable value that is set according to, for example, a remote control operation performed by a driver.

  Hereinafter, the structure of the lever 3 and the connection structure of the lever 3 and the rod 4 will be described in detail. As shown in FIG. 3, the lever 3 has a substantially U-shaped notch 3c at the lever tip 3b where the rod tip 4b is attached. In other words, a substantially U-shaped notch 3c is formed in the lever tip 3b in plan view. The notch 3 c functions as a bolt hole into which the screw portion 8 a of the bolt 8 for connecting the lever 3 and the rod 4 is inserted, and when the load 3 in the downward direction acts on the lever 3, the notch 3 c 3b is also dropped from the rod tip 4b to suppress the concentration of stress in the lever 3.

  The substantially U-shaped notch 3c is opened upward with the lever tip 3b and the rod tip 4b joined by bolts 8. That is, the notch 3c is formed by cutting out the edge 3d serving as the upper edge of the lever 3 in a substantially U-shape in a state where the lever 3 is assembled to the vehicle 10.

  As shown in FIG. 4, the rod tip 4b is attached to the lever tip 3b via the ball joint 7. More specifically, the rod tip 4b is attached to the lever tip 3b via the ball joint 7 by fastening the bolt 8 integrated with the ball joint 7 to the nut 9. When the rod tip 4b is thus attached to the lever tip 3b, the head 8b and the nut 9 of the bolt 8 hold the lever tip 3b, and the screw 8a of the bolt 8 has the notch of the lever 3. 3c.

  In a state where the lever 3 and the rod 4 connected to each other are assembled to the vehicle 10, the notch 3 c is opened upward above the screw portion 8 a of the bolt 8. Therefore, when a downward load F is input to the lever 3, the lever tip 3 b is allowed to move downward with respect to the screw portion 8 a of the bolt 8 by the notch 3 c, so that the It can slide down from between the head 8b and the nut 9.

[2. Action]
The operation of the above-described air suspension system 1 will be described with reference to FIGS. Here, it is assumed that the vehicle 10 travels in a cold region and an ice block 20 is formed in a portion of the side frame 11 located below the lever 3.

  As shown in FIG. 5A, in a state where the lump of ice 20 is fixed to the side frame 11, when the vehicle height is lowered, for example, for loading and unloading luggage, the side frame 11 moves downward. The ice block 20 also moves downward. Then, as shown in FIG. 5B, when the ice block 20 comes into contact with the lever 3 from above, a downward load F is input to the lever 3. Due to the load F, a moment M acts on the lever 3 to move the lever distal end 3b downward about the lever proximal end 3a.

  Here, since the lever distal end portion 3b is configured to be slidable from the rod distal end portion 4b by the notch 3c as described above, when a moment M having a predetermined magnitude or more acts thereon, it is shown in FIG. From the rod tip 4b. As a result, the lever 3 is released from the load F because the connection with the rod 4 is released and the lever 3 does not come into contact with the ice block 20. As a result, since the concentration of stress in the lever 3 is suppressed, the deformation of the lever 3 is prevented.

  In the conventional structure in which the notch 3c is not provided, the lever is unlikely to come off from the rod. For example, when a downward load is applied by the above-mentioned lump of ice, the lever may be deformed into a bent state. . Depending on how the lever is bent after the deformation, the detection value of the sensor may be smaller than the actual vehicle height. When such sensor erroneous detection occurs, the air pressure of the air suspension is increased in order to increase the vehicle height, so that the air suspension may be excessively pressurized.

  On the other hand, when the lever 3 of the present embodiment is separated from the rod 4 by receiving the downward load F as described above, the lever 3 swings downward by its own weight around the lever base end 3a. As a result, the angle θ described above increases, and the detection value of the sensor 5 becomes larger than the actual vehicle height. In other words, the sensor 5 erroneously detects a vehicle height higher than the actual vehicle height. As a result, the control device 15 determines that the detected value has become larger than the target value, and lowers the air pressure of the air suspension 2 to lower the vehicle height. Therefore, excessive pressurization of the air suspension 2 is prevented.

[3. effect]
According to the air suspension system 1, as described above, when a downward load F is applied to the lever 3, the lever tip 3b is separated from the rod tip 4b by the notch 3c, so that stress concentration on the lever 3 is reduced. Can be suppressed. That is, before the load F that is large enough to deform the lever 3 acts on the lever 3, the lever 3 is disconnected from the rod 4 and moves downward, so that the lever 3 is moved downward. Can be released from Therefore, it is possible to prevent the excessive load F from acting on the lever 3. Therefore, deformation of the lever 3 can be prevented.

[4. Modification]
In the above-described embodiment, the case where the ice block 20 is formed has been described as an example. However, according to the air suspension system 1, if a downward load F is input to the lever 3, the ice block 20 is formed. The lever 3 can be removed from the rod 4 by the notch 3c as described above, not only when the lump 20 is formed. For this reason, the deformation of the lever 3 can be prevented by suppressing the concentration of stress in the lever 3.

  When the lever 3 comes off the rod 4 as shown in FIG. 5C, the lever 3 does not change in accordance with the vehicle height. Will not change. When the change in the air pressure of the air suspension 2 and the detection value of the sensor 5 do not correspond to each other, for example, the control device 15 may determine the abnormality of the lever 3 and notify the user of the vehicle 10. When the lever 3 comes off the rod 4, the lever 3 and the rod 4 can be connected again by attaching the rod tip 4b to the lever tip 3b using the bolt 8 and the nut 9 described above.

  Each shape of the lever 3 and the rod 4 described above is an example. The lever 3 only needs to have at least the notch 3c described above at the mounting position of the rod 4, and may have a bent shape in advance according to, for example, the specifications of the sensor 5. Further, the rod 4 may be formed in an elongated plate shape similar to the lever 3. Note that the connection structure between the lever 3 and the rod 4 is not limited to the above-described structure, as long as the lever 3 is separated from the rod 4 by the notch 3c when receiving the downward load F.

  The air suspension system 1 does not have to be configured symmetrically. For example, the lever 3, the rod 4, and the sensor 5 may be arranged on only one of the left and right sides of the vehicle 10. The air suspension system 1 may be a front suspension applied to a front wheel (not shown) of the vehicle 10. Further, the vehicle to which the air suspension system 1 is applied is not limited to the truck as described above.

DESCRIPTION OF SYMBOLS 1 Air suspension system 2 Air suspension 3 Lever 3c Notch 4 Rod 5 Sensor 11 Side frame (body frame)
13 Rear axle (axle)
θ angle (tilt)

Claims (1)

An air suspension provided between the body frame and the axle;
A lever swingably attached to the body frame,
A rod swingably attached to the axle and the lever;
A sensor attached to the lever and detecting a vehicle height based on the inclination of the lever,
The air suspension system according to claim 1, wherein the lever has a substantially U-shaped notch opened upward at the mounting position of the rod.

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