JP2022061271A - Suspension device - Google Patents

Abstract

To provide a suspension device which can improve riding comfort and reliability even in the suspension device in which a suspension spring, an attenuation mechanism by fluid, and an actuator are provided side by side.SOLUTION: A suspension device 1 is provided between a vehicle body and a wheel in a vehicle. An attenuation mechanism 18 by fluid and an actuator having a motor 15 as a power source are provided side by side between the vehicle body and the wheel. The actuator is configured to drive a drive mechanism by the motor 15 through a connection section 17. The connection section has a clutch mechanism 13. The suspension device has a parallel mode in which attenuation force is generated by both of the attenuation mechanism by fluid and the actuator by connecting the clutch mechanism 13 and a single body mode in which attenuation force is generated by the attenuation mechanism by fluid by opening the clutch mechanism 13.SELECTED DRAWING: Figure 1

Description

The present invention relates to a suspension device, and more particularly to a suspension device suitable for cushioning vibration of an automobile or the like.

In recent years, the automobile market has tended to emphasize improvements in ride quality, comfort, and safety, and it is expected that these demands will increase for autonomous driving in the future. To meet these challenges, there is a suspension device. The suspension device is provided between the vehicle body and the wheels, and is a device that absorbs and alleviates the vertical vibration of the wheels due to the undulations of the road surface and prevents the vibration caused by the undulations of the road surface from being directly transmitted to the vehicle body.

Among them, the active suspension device (or electromagnetic suspension device) is expected to be particularly effective. The active suspension device is a suspension device capable of actively applying an arbitrary control force to the vehicle body side according to the road surface condition by an actuator.

As an example of a conventional active suspension device, a suspension spring provided between a vehicle body and a vehicle is provided with an actuator including a ball screw shaft, a ball nut, and a motor (see, for example, Patent Document 1).
The ball screw can convert linear motion and rotary motion, and when the motor is energized, the ball nut is driven and the control force can be actively applied to the vehicle body side, while when the ball nut is changed, the motor acts as a generator. However, it is possible to passively generate a damping force.

Japanese Unexamined Patent Publication No. 2018-177050

However, in such a configuration, the load on the motor becomes large, so it is necessary to consider the influence on the motor. For example, if the motor is damaged, the damping force cannot be obtained, so that the function as a suspension cannot be achieved. In order to prevent this and improve reliability, it is conceivable to install a fluid damping mechanism in parallel with the actuator. However, since the damping force of the fluid is always added to the damping force of the motor, the damping force becomes remarkable in the high frequency region where the vibration speed becomes large, and the riding comfort may be deteriorated.

An object of the present invention has been made in view of the above circumstances, and to provide a suspension device capable of improving ride quality and reliability even in a suspension device in which a suspension spring, a damping mechanism by a fluid, and an actuator are arranged side by side. There is something in it.

In order to achieve the above problems, the suspension device of the present invention is configured as described in the claims.
Specifically, the suspension device of the present invention is, for example, a suspension device provided between the vehicle body and wheels of a vehicle, and powers a damping mechanism by a fluid and a motor between the vehicle body and the wheels. Actuators as a source are provided in parallel, the actuator is configured to drive a drive mechanism by a motor via a coupling portion, the coupling portion comprises a clutch mechanism, and the suspension device connects the clutch mechanism. As a result, it has a parallel mode in which the damping force by both the damping mechanism by the fluid and the actuator is generated, and a single mode in which the damping force by the damping mechanism by the fluid is generated by releasing the clutch mechanism.

According to the present invention, the ride quality and reliability can be improved even in a suspension device in which a suspension spring, a damping mechanism by a fluid, and an actuator are arranged side by side.
Issues, configurations and effects other than those described above will be clarified by the following description of the embodiments.

FIG. 3 is a cross-sectional view of the shaft of the suspension device according to the first embodiment of the present invention. The model figure of the suspension apparatus which concerns on 1st Embodiment of this invention. The performance diagram of the suspension apparatus which concerns on 1st Embodiment of this invention. FIG. 3 is a cross-sectional view of a shaft of a suspension device according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view of a shaft of a suspension device according to a third embodiment of the present invention. The model figure of the suspension apparatus which concerns on 3rd Embodiment of this invention. FIG. 3 is a cross-sectional view of a shaft of a suspension device according to a fourth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is an axial sectional view of the suspension device according to the first embodiment of the present invention.
As shown in FIG. 1, the suspension device 1 includes a support portion 2 connected to the vehicle body side, a rod 3 connected to the support portion 2, a piston valve portion 4 integrally provided with the rod 3, and a piston valve portion 4. Containing a ball nut 5 integrally provided in, a ball screw shaft 8 screwed into the ball nut 5, a motor 15 for driving the ball screw shaft 8, a connecting portion 17 for connecting the ball screw shaft 8 and the motor 15, and a fluid 60. It has an outer cylinder 6 and an accumulator 16 communicating with the outer cylinder 6. The bottom side of the outer cylinder 6 is connected to the wheel side.

The suspension device 1 shown in FIG. 1 is provided with a fluid damping mechanism and an actuator.

The fluid damping mechanism in the suspension device according to the first embodiment of the present invention is configured as follows.
The main components of the fluid damping mechanism are a rod 3, a piston valve portion 4, an outer cylinder 6, and an accumulator 16. The rod 3 having one end connected to the support portion 2 is inserted into the outer cylinder 6 containing the fluid 60, and is installed so as to be movable up and down with respect to the outer cylinder 6. The piston valve portion 4 integrally provided at the other end of the rod 3 is provided so as to divide the inside of the outer cylinder 6 into upper and lower parts, and is installed in the outer cylinder 6 so as to be movable up and down. A plurality of hydraulic valves 40 are provided in the piston valve portion 4. One of the hydraulic valves 40 allows the fluid in the space below the piston valve portion 4 (lower chamber) to pass through the space above the piston valve portion 4 (upper chamber), and the other one Allows fluid in the upper chamber to pass through the lower chamber. When the rod 3 moves up and down, the fluid contained in the outer cylinder 6 passes through the hydraulic valve 40 of the piston valve portion 4, and a damping force due to the fluid is generated. At this time, since the inside of the outer cylinder 6 and the accumulator 16 communicate with each other, the volume of the outer cylinder 6 is compensated. The piston valve portion 4 and the accumulator 16 control the flow of the fluid to generate a damping force due to the fluid. The piston valve portion 4 and the accumulator 16 constitute a fluid damping force generation mechanism 18 in a fluid damping mechanism. The fluid damping mechanism itself is basically the same as the configuration of the conventional damping mechanism using a fluid.

The actuator in the suspension device according to the first embodiment of the present invention actively applies an arbitrary control force according to the road surface condition to the vehicle body side by using a ball screw shaft, a ball nut and a motor to improve the riding comfort. It is configured as follows.

The main components of the actuator are a rod 3, a piston valve portion 4, a ball nut 5, a ball screw shaft 8, a connecting portion 17, and a motor 15, of which the rod 3 and the piston valve portion 4 have a fluid damping mechanism. It has a common configuration with.

The rod 3 has an opening on the other end side and has a bottomed cylindrical shape having a hollow portion 7, and is arranged so that the ball screw shaft 8 is inserted into the hollow portion 7. The piston valve portion 4 is provided with a hole so that the ball nut 5 can be installed, and the piston valve portion 4 and the ball nut 5 are integrally provided so as to move up and down together. A shaft 9 is connected to the ball screw shaft 8, a gear 10 is connected to the shaft 9, and the lower end of the shaft 9 is installed at the bottom of the outer cylinder 6 via a bearing (not shown). The ball nut 5 is screwed with the ball screw shaft 8, whereby the rotational movement of the ball screw shaft 8 is converted into the vertical movement of the ball nut 5, and the vertical movement of the ball nut 5 is converted into the rotational movement of the ball screw shaft 8. Ru.

Further, a gear 11 arranged so as to mesh with the gear 10 and a shaft 12 connected to the gear 11 are installed inside the outer cylinder 6. The shaft 12 and the clutch mechanism 13 are connected to each other on the outside of the outer cylinder 6, and the shaft 12 is connected to the motor 15 installed in the housing 14 installed on the side wall of the outer cylinder 6 via the clutch mechanism 13. However, in the example shown in FIG. 1, the clutch mechanism 13 is located outside the outer cylinder 6, but it may be inside the outer cylinder 6. An electromagnetic clutch or the like is used as the clutch mechanism 13. Here, the shaft 9, the gear 10, the gear 11, the shaft 12, and the clutch mechanism 13 are collectively referred to as a connecting portion 17. The shaft 12 is appropriately supported by an outer cylinder 6 or the like via a bearing. Further, although a gear is used as a torque transmission mechanism from the shaft 9 to the shaft 12, for example, a belt or the like can also be used.

When the clutch mechanism 13 of the connecting portion 17 is connected, the vertical movement of the rod 3 is transmitted to the motor 15 via the ball nut 5, the ball screw shaft 8 and the connecting portion 17 integrated with the piston valve portion 4, and conversely. When the motor 15 is energized, the motor power is transmitted to the rod 3 via the connecting portion 17, the ball screw shaft 8 and the ball nut 5 integrated with the piston valve portion 4. From these, the rod 3, the piston valve portion 4, the ball nut 5, and the ball screw shaft 8 are drive mechanisms driven by the motor 15 of the power source via the connecting portion 17.

The rod 3 has a hollow portion 7 and is arranged so that the ball screw shaft 8 is inserted into the hollow portion 7, but the rod 3 is not necessarily limited thereto. For example, the ball nut 5 may be positioned on the outer peripheral side of the rod 3. However, it is preferable in terms of operation that the rod 3 has the hollow portion 7 and is arranged so that the ball screw shaft 8 is inserted into the hollow portion 7.

In the suspension device 1 according to the first embodiment shown in FIG. 1, a fluid damping mechanism and an actuator are provided in parallel between the vehicle body and the wheels of the vehicle. That is, a simple structure in which the piston valve portion 4 for moving the rod 3 up and down and the ball nut 5 are integrated realizes the parallel installation of the damping mechanism by the fluid and the actuator. The clutch mechanism 13 is provided, and the simple configuration of connecting and disengaging the clutch mechanism 13 makes it possible to select a parallel mode of the damping mechanism by the fluid and the actuator and a single mode of the damping mechanism by the fluid.

In the suspension device 1 according to the first embodiment shown in FIG. 1, when the clutch mechanism 13 is connected, the vertical movement of the rod 3 is transmitted to the motor 15, and conversely, when the motor is energized, the motor power is transmitted to the rod 3. Will be done. At the same time, the fluid contained in the outer cylinder 6 passes through the hydraulic valve 40 of the piston valve portion 4, and a damping force due to the fluid is generated. That is, when the clutch mechanism 13 is connected, the damping force due to the damping mechanism by the fluid and the damping force due to the actuator act on the rod 3 at the same time. On the other hand, when the clutch mechanism 13 is not connected (opened), the power from the rod 3 is not transmitted to the motor 15, and only the damping force due to the damping mechanism by the fluid acts on the rod 3. That is, in the suspension device 1 according to the first embodiment shown in FIG. 1, a state in which the damping force due to the damping mechanism by the fluid and the damping force by the actuator act simultaneously on the rod 3 connected to the support portion 2 (parallel mode). ) And the state in which the damping force by the damping mechanism by the fluid acts without the damping force by the actuator (single mode) can be selected.

From the above, the model diagram of the suspension device according to the first embodiment of the present invention can be represented as shown in FIG. The suspension device includes a suspension spring 30, an actuator in a dotted line (shown by the motor 15 which is a source of damping force in the drawing), and a fluid damping mechanism (a fluid damping force generation mechanism which is a source of damping force in the drawing). (Illustrated in 18). Further, a clutch mechanism 13 is provided as a component of the actuator. The suspension spring 30, the actuator, and the damping mechanism by the fluid are provided in parallel. The suspension device according to the first embodiment of the present invention is used together with the suspension spring 30. Normally, the suspension device is grasped as a suspension device including the suspension spring 30, but the target of the suspension device according to the first embodiment of the present invention is an actuator and a damping mechanism by a fluid. However, it does not exclude grasping as a suspension device including the suspension spring 30 as in the case of a normal suspension device.

When the clutch mechanism 13 is connected, the motor 15 and the fluid damping force generating mechanism 18 are in parallel mode, and when the clutch mechanism 13 is not connected (open), only the fluid damping force generating mechanism 18 is in a single mode.

Next, the case of switching between the parallel mode and the single mode will be described.
Since it is difficult to increase the control force by the motor 15 in the region where the response is fast, for example, when the vibration speed from the road surface (vibration speed of the wheel up and down) is small, the clutch mechanism 13 is connected and the motor 15 is used. By adjusting the control force and adjusting the stroke of the rod 3, the riding comfort can be improved. Further, when the vibration speed from the road surface is large, the clutch mechanism 13 is disconnected to exclude the damping force generated in the motor 15 so that the riding comfort can be improved. Since no load is applied to the motor 15 while it is disconnected, reliability can be improved.

In other words, the suspension device according to the first embodiment of the present invention is based on a damping mechanism by a fluid, and when the vibration speed is small, the suspension device actively applies an arbitrary control force to the vehicle body side according to the road surface condition by an actuator to ride the vehicle. It can be said that it is an improved active suspension device that improves comfort, and an active suspension device with improved reliability can be realized at low cost. For motor control in the actuator, motor control that obtains an arbitrary control force according to the road surface condition in the conventional active suspension device can be applied.

Further, the performance diagram of the suspension device according to the first embodiment of the present invention is as shown in FIG. The vertical axis shows the transmission force, and the horizontal axis shows the vibration speed. The horizontal axis may be a vibration frequency. It is shown that the positive side of the transmission force acts in the direction of pushing the vehicle body, and the negative side acts in the direction of lowering the vehicle body. The right side of the vibration speed shows the relationship between the vibration speed and the transmission force in the direction in which the suspension device extends, and the left side of the vibration speed shows the relationship between the vibration speed and the transmission force in the direction in which the suspension device contracts.

The performance line of the damping mechanism composed of a normal fluid damping force generation mechanism (the performance line in the case where the damping mechanism by fluid without an actuator corresponds to the low speed region to the high speed region) is shown in the first embodiment of the present invention. The performance line of the suspension device is shown by the solid line and the part surrounded by the solid line. The alternate long and short dash line and the solid line extending in the same direction as the alternate long and short dash line indicate the performance line of only the damping mechanism by the fluid used in the suspension device according to the first embodiment of the present invention.

When the vibration speed is small (low speed region or low frequency region in the figure), the suspension device according to the first embodiment of the present invention connects the clutch mechanism 13 and controls the motor 15 in a wide range (surrounded by a solid line in the figure). The transmission power can be adjusted over the part). Further, when the vibration speed is high (high-speed region or high-frequency region in the figure), the clutch mechanism 13 is not connected (opened), so that only the damping by the fluid damping force generation mechanism 18 is performed. The connection / release of the clutch mechanism 13 was obtained, for example, by inputting a measurement signal 25 from an acceleration sensor or a stroke sensor to the control device 26 and obtaining a vibration speed (vibration frequency) from the measurement signal in the control device 26. If the vibration speed (vibration frequency) is within a predetermined vibration speed (frequency) (low speed region or low frequency region), the clutch mechanism 13 is connected to control the motor 15, and the obtained vibration speed (vibration frequency) is also controlled. ) Exceeds a predetermined vibration speed (frequency) (if it is in a high-speed region or a high-frequency region), the clutch mechanism 13 is released.

In order to improve the riding comfort, it is desirable to increase the damping force (transmission force) in the low vibration speed region and decrease the damping force (transmission force) in the high vibration speed region. In the first embodiment of the present invention, since the motor 15 can be controlled to adjust (can be increased) the transmission force in the low speed region where the transmission force is required, it is not necessary to set the damping by the fluid damping force generation mechanism 18 to be large. Therefore, as shown in FIG. 3, the transmission force of the fluid damping mechanism of the suspension device according to the first embodiment of the present invention is made smaller than that of the damping mechanism composed of a normal fluid damping force generation mechanism (soft one). It is also possible to obtain the effect that the riding comfort can be further improved for protrusion input or the like in which it is desirable that the transmission force is small.

A second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a diagram showing a cross-sectional view of a shaft of the suspension device according to the second embodiment of the present invention. The description of the same configuration as that of the first embodiment will be omitted. In the second embodiment, the configuration of the connecting portion 17 is different from that in the first embodiment.

In the second embodiment, the speed increaser 19 composed of the gear 10 and the plurality of gears corresponding to the gear 11 in the first embodiment is located outside the outer cylinder 6. In the example shown in FIG. 4, it is located in the housing 24 formed below the outer cylinder 6. The bottom side of the housing 24 is connected to the wheel side. A shaft 9 is connected to the ball screw shaft 8, and the lower end of the shaft 9 is installed at the bottom of the housing 24 via a bearing (not shown). One of the gears constituting the speed increaser 19 is connected to the shaft 9. One of the gears constituting the speed increaser 19 is connected to the shaft 12', and the lower end of the shaft 12'is installed at the bottom of the housing 24 via a bearing (not shown). The shaft 12'and the clutch mechanism 13 are connected in the housing 24, and the speed increaser 19 is connected to the motor 15 via the clutch mechanism 13.

According to the present embodiment, it is possible to prevent wear powder generated by friction and wear of the gear 10 and the gear 11 from invading the outer cylinder 6 and causing a problem, and the reliability can be further improved. Other configurations and effects are the same as those in the first embodiment.

A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a diagram showing a cross-sectional view of a main part of the suspension device according to the third embodiment of the present invention. The description of the same configuration as that of the first embodiment will be omitted.

The outer circumference of the ball nut 5 in the first embodiment is machined to form a ring-shaped convex portion 5a protruding toward the outer diameter side. Further, the inner circumference of the piston valve portion 4 is machined to form a ring-shaped convex portion 4a protruding toward the inner diameter side. A ring-shaped rubber 20 is attached so as to be in contact with the outer periphery of the ball nut 5, and the ring-shaped rubber 20 is formed in the annular space formed between the convex portion 4a and the convex portion 5a and in the annular space below the convex portion 5a. To place. Then, a ring-shaped stopper 21 is attached below the piston valve portion 4 so as to fix the ring-shaped rubber 20 arranged in the space below the convex portion 5a between the convex portion 5a and the convex portion 5a. As a result, the piston valve portion 4 and the ball nut 5 are integrated via the ring-shaped rubber 20. Note that the hydraulic valve 40 is not shown in FIG.

A model diagram of the suspension device according to the third embodiment of the present invention can be represented as shown in FIG. A rubber 20 is provided in series with the motor 15 of the actuator.

The ball nut 5 and the ball screw shaft 8 cannot respond in a region where the vibration frequency is high due to a pot hole or the like, and there is a possibility that the vibration is directly transmitted to the vehicle body. In the present embodiment, since the high frequency vibration can be absorbed by the rubber 20, it is possible to prevent the ride quality from deteriorating in the high frequency vibration region. Other configurations and effects are the same as those in the first embodiment. Moreover, this embodiment can be applied to the second embodiment.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a diagram showing a cross-sectional view of a main part of the suspension device according to the fourth embodiment of the present invention. The description of the same configuration as that of the first embodiment will be omitted.

In the fourth embodiment, a communication hole 22 for communicating the hollow portion 7 and the lower chamber 23, which is the space below the piston valve portion 4, is provided inside the ball screw shaft 8 in the first embodiment. The opening on the hollow portion 7 side is located at the upper end of the ball screw shaft 8 in consideration of workability (not limited to that), but is not limited to that, and is located on the side surface of the ball screw shaft 8 as in the lower chamber 23 side. You can do it.
The ball screw shaft 8 is moved in and out of the hollow portion 7 by the vertical movement of the rod 3 and the piston valve portion 4 fixed to the rod 3. Since the fluid filled in the hollow portion 7 at that time passes through the gap between the ball nut 5 and the ball screw shaft 8, it is conceivable that a damping force is also generated there. Therefore, by providing the communication hole 22, a fluid path different from the gap between the ball nut 5 and the ball screw shaft 8 is prepared between the hollow portion 7 and the lower chamber 23, whereby the ball nut 5 and the ball screw are provided. It becomes possible to remove an unnecessary damping force generated by the fluid passing through the gap of the shaft 8. Other configurations and effects are the same as those in the first embodiment. Moreover, this embodiment can be applied to the second embodiment and the third embodiment.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.
In addition, the citations of other claims in the claims of the scope of claims are single-term citations in order to make the description of the claims in the citation form easier to understand, but the present invention is in the claims of the citation form. , A form of quoting a plurality of claims (multi-claim citation), and a form of quoting a plurality of multi-claim citations.

1 ... Suspension device, 2 ... Support part, 3 ... Rod, 4 ... Piston valve part, 5 ... Ball nut, 6 ... Outer cylinder, 7 ... Hollow part, 8 ... ball screw shaft, 9 ... shaft, 10 ... gear, 11 ... gear, 12 ... shaft, 13 ... clutch mechanism, 14 ... housing, 15 ... motor, 16 ... Accumulator, 17 ... Connecting part, 18 ... Fluid damping force generation mechanism, 19 ... Accelerator, 20 ... Rubber, 21 ... Stopper, 22 ... Communication hole, 23 ... lower room, 26 ... control device.

Claims (9)

A suspension device installed between the vehicle body and wheels.
A fluid damping mechanism and an actuator powered by a motor are provided in parallel between the vehicle body and the wheels.
The actuator is configured to drive a drive mechanism by a motor via a connecting portion.
The connecting portion is provided with a clutch mechanism.
The suspension device has a parallel mode in which a damping force by both the fluid damping mechanism and the actuator is generated by connecting the clutch mechanism, and a damping force by the fluid damping mechanism by opening the clutch mechanism. A suspension device characterized by having a single mode to generate. In the suspension device according to claim 1,
The drive mechanism of the actuator is
A rod whose one end is connected to the vehicle body side, a ball nut fixed to the other end side of the rod, and a ball screw shaft screwed to the ball nut are provided.
The ball screw shaft is a suspension device driven by the motor via the connecting portion. In the suspension device according to claim 1,
The damping mechanism by the fluid is
An outer cylinder containing a fluid, a rod whose one end is connected to the vehicle body side outside the outer cylinder and whose other end is located inside the outer cylinder, and a rod fixed to the other end of the rod and moved up and down inside the outer cylinder. It is a piston valve portion provided so as to be able to move up and down in the outer cylinder while being divided into two parts, and a valve through which the fluid flows is provided from the lower side to the upper side of the piston valve part and from the upper side to the lower side of the piston valve part. It is equipped with a piston valve portion and an accumulator that communicates with the inside of the outer cylinder.
The drive mechanism of the actuator is
A ball nut fixed to the front piston valve portion and a ball screw shaft screwed to the ball nut are provided.
The ball screw shaft is a suspension device driven by the motor via the connecting portion. In the suspension device according to claim 3,
The piston valve portion is formed with a hole capable of accommodating the ball nut, and the ball nut is provided integrally in the hole.
A suspension device in which a bottomed hollow portion having an opening at the other end of the rod is formed, and the ball screw shaft is inserted into the hollow portion. In the suspension device according to claim 4,
A suspension device in which the connecting portion is arranged outside the outer cylinder. In the suspension device according to claim 4,
A suspension device in which a ring-shaped rubber is arranged on the outer peripheral side of the ball nut. In the suspension device according to claim 4,
The ball screw shaft is a suspension device in which a communication hole is formed to communicate between the hollow portion and the lower portion of the piston valve portion. In the suspension device according to claim 1,
The parallel mode is a suspension device applied in a region where the vertical vibration speed of the wheel is smaller than that of the single mode. In the suspension device according to claim 8,
A suspension device to which the parallel mode is applied if the upper and lower vibration speeds of the wheels are within a predetermined vibration speed, and the single mode is applied if the upper and lower vibration speeds of the wheels exceed a predetermined vibration speed.

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