Suspension device

Abstract

The problem to be solved by the present invention is to provide a suspension device for a vehicle that can appropriately utilize the damping forces (thrusts) of an electric damper and a hydraulic damper according to road surface conditions and can improve the riding comfort of the vehicle. To solve the above problems, there is provided a suspension device for a vehicle, comprising: an electric damper that operates with electricity; a hydraulic damper that operates with hydraulics; a road surface condition detection unit that detects the road surface condition in front of the tires of the vehicle; and a control unit that operates at least one of the aforementioned electric damper and the aforementioned hydraulic damper based on the detection result of the road surface condition detection unit.

Description

Technical Field

[0001] The present invention relates to a suspension device. Background Art

[0002] Conventionally, a suspension device for a vehicle is known, in which a hydraulically operated hydraulic damper is housed inside an electrically operated electric damper (for example, see Patent Document 1).

[0003] In this suspension device, the electric damper is configured to generate a damping force at the center of the extension / contraction operation range and a relatively small damping force at the end of the operation range. On the other hand, the hydraulic damper is configured to generate a small damping force at the center of the contraction / extension operation range and a large damping force at the end of the operation range. Thus, it is generally considered that good damping force is obtained throughout the contraction / extension operation range.

[0004] [Prior Art Documents]

[0005] (Patent Document)

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-227927 Summary of the Invention

[0007] [Problems to be Solved by the Invention]

[0008] However, in the above-described suspension device, since the damping force of the hydraulic damper at the end of the contraction / extension operation range is greater than the damping force of the electric damper, even on a road surface condition where it is desired that the electric damper generates a thrust at the end of the operation range, the thrust of the electric damper is consumed by the damping force of the hydraulic damper, and the hydraulic damper may interfere with the thrust of the electric damper. Therefore, in the conventional suspension device, there is a problem from the viewpoint of improving the ride comfort of the vehicle.

[0009] An object of the present invention is to provide a suspension device for a vehicle that can appropriately utilize the damping forces (thrusts) of an electric damper and a hydraulic damper according to road surface conditions and can improve the ride comfort of the vehicle.

[0010] [Means for Solving the Problems]

[0011] (1) The suspension device of the vehicle of the present invention (for example, the suspension device 1 described later) includes: an electric damper (for example, the electric damper 6 described later), which operates with electricity; a hydraulic damper (for example, the hydraulic damper 7 described later), which operates with hydraulic pressure; a road surface condition detection unit (for example, the road surface condition detection unit 200 described later), which detects the road surface condition in front of the vehicle's tire; and a control unit (for example, the control unit 300 described later), which operates at least one of the aforementioned electric damper and the aforementioned hydraulic damper based on the detection result of the aforementioned road surface condition detection unit.

[0012] (2) Optionally, in the suspension device of the vehicle described in the above (1), the control unit controls in the following manner. When it is determined that the road surface condition detected by the road surface condition detection unit exceeds a specified threshold that can be handled by the electric damper alone, the hydraulic damper is operated.

[0013] (3) Optionally, in the suspension device of the vehicle described in the above (1), the control unit controls in the following manner. In at least any one of the cases where the vehicle is in an energy-saving mode, where a command cannot be output due to a failure of the control unit, and where the suspension device cannot be electrically controlled, the hydraulic damper is operated.

[0014] (Effect of the invention)

[0015] According to the above (1), it is possible to grasp the information of the road surface condition by using the road surface condition detection unit, and it is possible to operate at least one of the electric damper and the hydraulic damper according to the road surface condition. For example, when it is necessary to generate the thrust of the electric damper, the damping force of the hydraulic damper can be prevented from interfering with the operation of the electric damper in a way that does not generate the damping force of the hydraulic damper. Therefore, the riding comfort of the vehicle can be improved. In addition, when the directions of the thrusts generated by the electric damper and the hydraulic damper are the same, the hydraulic damper can also operate both the two electric dampers and the hydraulic damper to assist the thrust of the electric damper. Therefore, the required thrust generated by the electric damper can be reduced, and the miniaturization of the suspension device can be achieved.

[0016] According to the above (2), when a large input that cannot be handled by the electric damper alone is detected, for example, when the tire has to cross a large height difference, the hydraulic damper can be operated to utilize the damping force (thrust) of the hydraulic damper. In the case where both the electric damper and the hydraulic damper are operated, the hydraulic damper can appropriately assist the damping force (thrust) of the electric damper, and the riding comfort of the vehicle can be further improved.

[0017] According to the above (3), when the vehicle is in the energy-saving mode due to a decrease in battery capacity or the like, when it is impossible to output a command due to a failure of the control unit or the like, and when it is impossible to electrically control the suspension device due to heat or the like, the hydraulic damper is operated, so that the thrust of the electric damper can be reduced, and thus, the power consumption of the battery can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a block diagram showing a schematic configuration of a suspension device of a vehicle according to an embodiment of the present invention.

[0019] Figure 2 is a sectional view of a suspension main body of a suspension device of a vehicle according to an embodiment of the present invention.

[0020] Figure 3 is to Figure 2 a sectional view showing an enlarged view of part A in

[0021] Figure 4 is a perspective view showing an enlarged view of a gate plate member provided on a suspension main body of a suspension device of a vehicle according to an embodiment of the present invention.

[0022] Figure 5 is to Figure 3 a sectional view showing an enlarged view of a part of

[0023] Figure 6 is to show Figure 5 a sectional view at the maximum stroke of the electric damper in

[0024] Figure 7 is a conceptual diagram for explaining a state in which an electric damper operates alone in a suspension main body of a suspension device of a vehicle according to an embodiment of the present invention.

[0025] Figure 8 is a conceptual diagram for explaining a state in which a hydraulic damper contracts and operates in a suspension main body of a suspension device of a vehicle according to an embodiment of the present invention.

[0026] Figure 9 is a conceptual diagram for explaining a state in which a hydraulic damper extends and operates in a suspension main body of a suspension device of a vehicle according to an embodiment of the present invention.

[0027] Figure 10A is a graph showing a thrust diagram of the electric damper.

[0028] Figure 10B is a graph showing a damping force diagram of the hydraulic damper.

[0029] Figure 10C is a graph showing characteristics of the electric damper and the hydraulic damper.

[0030] Figure 11 It is a flowchart showing an example of the control of the suspension device of a vehicle according to an embodiment of the present invention.

[0031] Figure 12 It is a diagram for explaining the thrust (shrinking side) generated by the electric damper when the electric damper and the hydraulic damper are operating.

[0032] Figure 13 It is a diagram for explaining the thrust (shrinking side) generated by the electric damper when the electric damper operates alone.

[0033] Figure 14 It is a diagram for explaining the actual thrust (elongating side) generated by the electric damper when the electric damper operates alone.

[0034] Figure 15 It is a diagram for explaining the actual thrust (elongating side) generated by the electric damper when the electric damper and the hydraulic damper are operating.

[0035] Figure 16A It is a chart showing the damping force diagram of the semi-active damper unit.

[0036] Figure 16B It is a chart showing the characteristics of the electric damper and the semi-active damper.

[0037] Figure 17 It is a chart for explaining the respective damping forces of the electric damper and the hydraulic damper. Detailed Embodiment

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 It is a block diagram showing the schematic structure of the suspension device of a vehicle according to an embodiment of the present invention. The suspension device 1 is configured to include a suspension main body 100, a road surface condition detection unit 200, and a control unit 300.

[0039] The suspension main body 100 integrally includes an electric damper (electromagnetic damper) 6 that operates with electricity and a hydraulic damper 7 that operates with hydraulic pressure (oil pressure). In the suspension main body 100 of the present embodiment, the hydraulic damper 7 is coaxially provided inside the electric damper 6. Therefore, first, use Figures 2 to 6 to explain the structure of the suspension main body 100.

[0040] Figure 2 It is a cross-sectional view of the suspension main body of the suspension device according to an embodiment of the present invention. Figure 3 It is to Figure 2 The cross-sectional view of the enlarged A part of Figure 3The front end side on the right is referred to as the front side. Sometimes, the Figure 3 left side in the

[0041] The hydraulic damper 7 is composed of a rod 11, a piston 12, valves 13, 14, etc. The hydraulic damper 7 functions as a conventional suspension. That is, a rod 11 coaxial with the inner cylinder 3 is accommodated inside the inner cylinder 3. The rod 11 can move inside the inner cylinder 3 in the longitudinal direction of the inner cylinder 3 ( Figure 3 the left - right direction). The front end side (right side) in the longitudinal direction of the rod 11 is provided with a piston 12. The outer peripheral surface of the piston 12 moves along the inner peripheral surface of the inner cylinder 3.

[0042] By means of the piston 12, the inside of the inner cylinder 3 is partitioned into a first liquid chamber 4 on the rear side of the piston 12 and a second liquid chamber 5 on the front side of the piston 12. A cylindrical magnet 21 is provided on the piston 12. A magnet inner flow path 22 is provided inside the magnet 21, and the magnet inner flow path 22 communicates the first liquid chamber 4 with the second liquid chamber 5. A valve 13 is provided at the head of the piston 12 in the magnet inner flow path 22. A valve 14 is provided at the head of the inner cylinder 3. The valve 14 can communicate the inside of the inner cylinder 3 with the space 15 between the inner cylinder 3 and the outer housing 2. The space inside the suspension main body 100 is filled with a liquid such as oil. Therefore, in a state where the valves 13, 14 are open, when the rod 11 is displaced between the first liquid chamber 4 and the second liquid chamber 5, the liquid circulates in the magnet inner flow path 22 and the valves 13, 14. Thus, the piston 12 can move, and the hydraulic damper 7 can generate hydraulic pressure.

[0043] The electric damper 6 is composed of a magnet 21, a coil 23, etc. The electric damper 6 functions as an electromagnetic suspension. That is, a cylindrical coil 23 (actuator) is provided between the outer housing 2 and the inner cylinder 3. When this coil 23 is energized, a magnetic field is generated, and this magnetic field acts on the magnet 21, whereby the piston 12 and the rod 11 can be moved in their axial directions. A space 16 is provided between the outer housing 2 and the inner cylinder 3. A coil inner passage 24 is provided inside the coil 23. The coil inner passage 24 communicates the space 15 with the space 16.

[0044] A bypass passage chamber 31 is provided inside the space 16 and outside the inner cylinder 3. A bypass hole 33 is provided on the rear side of the wall of the inner cylinder 3 constituting the bypass passage chamber 31, and the bypass hole 33 communicates the first liquid chamber 4 with the bypass passage chamber 31. A bypass hole 34 is provided on the front end side of the wall 32 on the space 16 side of the bypass passage chamber 31, and the bypass hole 34 communicates the space 16 with the bypass passage chamber 31. Via the bypass passage chamber 31 and the bypass holes 33, 34, the first liquid chamber 4 and the space 16 can be communicated.

[0045] Similarly, a bypass passage chamber 35 is provided inside the space 15 and outside the inner cylinder 3. A bypass hole 36 is provided on the rear side of the wall 37 on the space 15 side of the bypass passage chamber 35, and the bypass hole 36 conducts the space 15 and the bypass passage chamber 35. The front end side of the bypass passage chamber 35 is open, and the second liquid chamber 5 and the space 15 can communicate with each other via the bypass passage chamber 35 and the bypass hole 36.

[0046] In this way, the bypass passage chamber 31, the space 16, the inner-coil passage 24, the space 15, the bypass passage chamber 35, etc. constitute a communication passage that bypasses the valve 13 to connect the first liquid chamber 4 and the second liquid chamber 5.

[0047] An annular gate member 41 is slidably wound around the bypass hole 34 of the inner cylinder 3. Figure 4 It is a perspective view showing an enlarged part of the gate member 41. A plurality of punching holes 42 are formed on the annular part of the gate member 41. A flange-like member 41a protrudes outward from the annular gate member 41. Return Figure 3 , the gate member 41 is urged rearward in the axial direction of the inner cylinder 3 by a spring 49. In this state, the gate member 41 blocks the bypass hole 34. The gate member 41 is made of metal and moves by overcoming the elastic force of the spring 49 by the action of the magnetic field generated by energizing the coil 23. Thereby, the positions of the bypass hole 34 and the punching hole 42 are aligned, and the bypass hole 34 is opened.

[0048] In Figure 3 , an annular gate member 46 is also slidably wound around the bypass hole 36 of the inner cylinder 3. The structure of the gate member 46 is the same as that of the gate member 41. A plurality of punching holes 47 are formed on the annular part of the gate member 46. The gate member 46 is urged forward in the axial direction of the inner cylinder 3 by a spring 48. In this state, the gate member 46 blocks the bypass hole 36. The gate member 46 is made of metal and moves by overcoming the elastic force of the spring 48 by the action of the magnetic field generated by energizing the coil 23. Thereby, the positions of the bypass hole 36 and the punching hole 47 are aligned, and the bypass hole 36 is opened.

[0049] When the bypass holes 34 and 36 are opened, the bypass passage chamber 31, the space 16, the inner-coil passage 24, the space 15, and the bypass passage chamber 35 can bypass the valve 13 to form a communication passage connecting the first liquid chamber 4 and the second liquid chamber 5. The gate members 41 and 46 constitute a switch portion for opening and closing the communication passage at this time.

[0050] As can be seen from the above description, the electric damper 6 uses the magnetic force generated by a linear motor composed of a magnet 21, a coil 23, etc. When the gate members 41 and 46 serving as the switch portion are opened, the magnetic force generated by the aforementioned linear motor is used.

[0051] Figure 5 Is going toFigure 3 A partially enlarged sectional view. Figure 6 It shows Figure 5 a diagram of the maximum stroke of the electric damper 6 in Figure 6 As shown, the bypass hole 33 between the first liquid chamber 4 and the bypass passage chamber 31 is set at a position not blocked by the magnet 21 at the maximum stroke of the electric damper 6.

[0052] Next, use Figures 7 to 9 to explain the function of the suspension main body 100 of this embodiment. Figures 7 to 9 These are conceptual diagrams respectively explaining the function of the suspension main body 100.

[0053] As Figure 7 shown, during normal operation, the suspension main body 100 operates the electric damper 6 alone (ON) and sets the hydraulic damper 7 to non-operation (OFF). In addition, normal operation refers to the time when the vehicle is driving normally on the road surface. When the user can select a driving mode, normal operation refers to the time when the vehicle is set to the normal mode and driving on the road surface.

[0054] In the suspension main body 100, when the electric damper 6 is operated alone and the hydraulic damper 7 is set to non-operation, the shutter members 41, 46 are operated to open. Thus, each chamber is connected via the aforementioned communication channels, and the liquid moves as shown by the arrows in Figure 7 and does not pass through the valves 13, 14. Therefore, no hydraulic pressure is generated and no liquid damping is generated. The electric damper 6 controls the piston 12 using electromagnetic force to generate a damping force against the vibration of the vehicle.

[0055] Figure 8 and Figure 9 show the case where the hydraulic damper 7 is operated (ON). Figure 8 It shows that when the rod 11 contracts (into the suspension main body 100), Figure 9 and it shows that when the rod 11 extends (out of the suspension main body 100). At this time, the shutter members 41, 46 are closed. In this way, Figure 7 the flow of the liquid shown by the arrows in disappears. Therefore, the hydraulic damper 7 generates a damping force against the vibration of the vehicle in the same manner as a normal double-cylinder damper, using the valves 13, 14.

[0056] Return Figure 1, as described above, the suspension main body 100 has the electric damper 6 and the hydraulic damper 7 that can operate independently of each other. Further, the suspension main body 100 has a switching unit 8 that switches whether the electric damper 6 and the hydraulic damper 7 can operate (ON / OFF). The switching unit 8 of the suspension main body 100 in the present embodiment outputs or cuts off current to the coil 23 and operates the above-described shutter members 41 and 46 in an open and closed manner.

[0057] The road surface condition detection unit 200 detects the road surface condition in front of the tire on which the vehicle is about to travel and obtains information on the road surface condition. The road surface condition detection unit 200 has a detector 201 and an information processing unit 202.

[0058] The detector 201 is a road surface measurement preview sensor that detects the road surface condition on the front side of the front wheels of the vehicle. The detector 201 is mounted on the vehicle so as to be able to detect the convex state of the road surface on which the vehicle is about to travel. As a specific detector 201, for example, an imaging device such as a camera having an image sensor such as a Charge Coupled Device (CCD), a radio wave detection device such as a millimeter wave radar, or an optical detection and ranging device such as Laser Imaging Detection and Ranging (LIDAR) can be used. The detection information on the road surface condition detected by the detector 201 is output to the information processing unit 202.

[0059] The information processing unit 202 processes the detection information on the road surface condition input from the detector 201 and generates information on the size (height of the height difference) of the convex portion of the road surface as information on the quantitative road surface condition. Thus, the size of the convex portion of the road surface on which the vehicle is about to travel can be quantitatively grasped. The information on the size of the convex portion of the road surface generated by the information processing unit 202 is output to the control unit 300.

[0060] The control unit 300 determines whether the electric damper 6 and the hydraulic damper 7 of the suspension main body 100 can operate separately based on the detection result of the road surface condition detection unit 200 and controls the ON / OFF of the respective operations of the electric damper 6 and the hydraulic damper 7. The control unit 300 has a calculation unit 301 and a drive control unit 302.

[0061] The calculation unit 301 compares the information on the size of the convex portion of the road surface input from the information processing unit 202 of the road surface condition detection unit 200 with a preset specified threshold value and determines whether the size of the convex portion of the road surface (height of the convex portion) exceeds the threshold value. The calculation unit 301 outputs the determination result to the drive control unit 302.

[0062] The threshold is set to the size of the road surface bumps that can be handled by the electric damper 6. For example, the threshold can represent the size of the road surface bumps as follows: the size of the road surface bumps that are determined to require a thrust greater than the damping force that the electric damper 6 can output, the size of the road surface bumps that are determined to require the electric damper 6 to perform a certain amount or more of shock absorption operation, or the size of the road surface bumps that are determined to require an operation output exceeding the response performance of the electric damper 6. When the threshold exceeds the size of such road surface bumps, it is determined that the independent operation of the electric damper 6 will have a greater impact on the ride comfort of the vehicle.

[0063] The drive control unit 302 operates the switching unit 8 of the suspension main body 100 according to the determination result input from the calculation unit 301 to switch the ON / OFF of the operation of the electric damper 6 and the hydraulic damper 7 of the suspension main body 100. Thereby, the gate members 41 and 46 of the suspension main body 100 are opened and closed. In the suspension main body 100 shown in the present embodiment, as described above, when the gate members 41 and 46 are opened, the electric damper 6 operates independently (ON), and the hydraulic damper 7 forms a non-operating (OFF) state. When the gate members 41 and 46 are closed, the electric damper 6 forms a non-operating (ON) state, and the hydraulic damper 7 operates independently (ON).

[0064] Figure 10A is a thrust diagram showing the electric damper 6. Figure 10B is a damping force diagram showing the hydraulic damper 7. As Figure 10C shown, in the suspension device 1 of the present embodiment having the above-described electric damper 6 and hydraulic damper 7, the two characteristics of the characteristic X1 of the electric damper 6 and the characteristic X2 of the hydraulic damper 7 can be switched and used. Therefore, the suspension device 1 is controlled in the region using the characteristic X1 of the electric damper 6 by operating the electric damper 6 independently (ON) during normal operation. When the size of the road surface bumps input from the road surface condition detection unit 200 exceeds the threshold and an operation output exceeding the response performance of the electric damper 6 is required, it is controlled by operating the hydraulic damper 7 (ON) and using the characteristic X2 of the hydraulic damper 7.

[0065] Next, an example of the control of the suspension device 1 of the present embodiment will be described using the Figure 11 flowchart shown. In addition, the control of the suspension device 1 of the present embodiment starts with the drive start operation (ignition switch ON operation) of the vehicle, and the loop process continues until the drive end operation (ignition switch OFF operation) is executed.

[0066] When the driving of the vehicle starts, the suspension device 1 is set to the normal operation mode. In the normal operation mode, the shutter members 41 and 46 of the suspension main body 100 are opened. As a result, the electric damper 6 is set to the operating (ON) state, and the hydraulic damper 7 is set to the non-operating (OFF) state (step S1).

[0067] If the vehicle starts to run, the detector 201 of the road surface condition detection unit 200 constantly detects the road surface condition in front of the tire. The road surface condition detection unit 200 generates information on the quantitative road surface condition based on the detection information of the road surface condition detected by the detector 201 in the information processing unit 202, and outputs it to the control unit 300. As a result, the control unit 300 compares the information on the size of the convex portion of the road surface with a threshold value in the calculation unit 301, and determines whether the size of the convex portion of the road surface exceeds a specified threshold value (step S2).

[0068] When the determination result does not exceed the threshold value (step S2: No), the suspension device 1 returns to the process of step S1, maintains the setting of the electric damper 6: ON and the hydraulic damper 7: OFF, and continuously detects the information on the road surface condition.

[0069] On the other hand, when the determination result exceeds the threshold value (step S2: Yes), it is determined that there is a large input (large height difference) exceeding the range that can be handled by the electric damper 6. The control unit 300 outputs a current for closing the shutter members 41 and 46 to the switching unit 8 of the suspension main body 100 via the drive control unit 302. As a result, the shutter members 41 and 46 are closed, and the hydraulic damper 7 is set to the operating (ON) state (step S3). In the suspension main body 100 of the present embodiment, if the shutter members 41 and 46 are closed, the electric damper 6 is switched to the non-operating (OFF) state.

[0070] By operating the hydraulic damper 7 instead of the electric damper 6, when the rod 11 contracts, the damping force of the hydraulic damper 7 is utilized. Therefore, even for a large input (height difference) that cannot be handled by the electric damper 6, the suspension main body 100 can appropriately handle it, thereby improving the riding comfort when there is a large input.

[0071] After the hydraulic damper 7 operates in step S3, if the large convex portion that cannot be handled by the electric damper 6 disappears, the process returns to step S1. Therefore, the suspension main body 100 returns to the initial state where the electric damper 6 is set to the operating (ON) state and the hydraulic damper 7 is set to the non-operating (OFF) state.

[0072] In addition, as Figure 1As shown, the suspension device 1 of the present embodiment is configured such that the vehicle mode information of the host vehicle is also input to the drive control unit 302 of the control unit 300. The mode information is information indicating that the host vehicle is operating in an energy-saving mode. The energy-saving mode may be a mode arbitrarily set by the user. The energy-saving mode may also be a mode automatically set when it is detected that the battery capacity of the host vehicle has dropped below a certain value. In the case where the host vehicle is a vehicle driven by an electric motor, the energy-saving mode may be a mode automatically set when it is detected that the temperature of the electric motor is above a specified threshold value, or may be a mode automatically set when it is detected that the product value of the current of the electric motor is above a specified threshold value within an arbitrary time period. If it is determined from the input mode information that the host vehicle is in the energy-saving mode, the control unit 300 controls the hydraulic damper 7 to operate (ON) regardless of the detection result of the road surface condition detection unit 200. Thus, since the electric damper 6 becomes non-operational (OFF), the power consumption of the battery can be suppressed.

[0073] As described above, the suspension device 1 of the vehicle of the present embodiment includes: an electric damper 6 that operates with electricity; a hydraulic damper 7 that operates with hydraulic pressure; a road surface condition detection unit 200 that detects the road surface condition in front of the tires of the vehicle; and a control unit 300 that switches and controls whether the electric damper 6 and the hydraulic damper 7 can operate respectively based on the detection result of the road surface condition detection unit 200. Accordingly, the information on the road surface condition can be grasped by the road surface condition detection unit 200, and the electric damper 6 and the hydraulic damper 7 can be appropriately switched according to the road surface condition. For example, when it is not necessary to generate the thrust of the electric damper 6, the damping force of the hydraulic damper 7 can be prevented from interfering with the operation of the electric damper 6. Therefore, the riding comfort of the vehicle can be improved.

[0074] The control unit 300 of the present embodiment controls as follows. When it is determined that the road surface condition detected by the road surface condition detection unit 200 exceeds a specified threshold value that can be handled by the electric damper 6 alone, the hydraulic damper 7 is made to operate. Accordingly, when a large input that cannot be handled by the electric damper 6 is detected, for example, when the tire crosses a large height difference, the hydraulic damper 7 can be made to operate and the damping force (thrust) of the hydraulic damper 7 can be utilized. Thus, the riding comfort of the vehicle can be further improved.

[0075] The control unit 300 of the present embodiment controls in the following manner. When the vehicle is in an energy-saving mode, when a command cannot be output due to a failure of the control unit 300, etc., and when the suspension device 1 cannot be electrically controlled, the hydraulic damper 7 operates. Accordingly, when the vehicle is in an energy-saving mode due to a decrease in battery capacity, etc., when a command cannot be output due to a failure of the control unit 300, etc., and when the suspension device 1 cannot be electrically controlled due to heat, etc., the hydraulic damper 7 operates, so that the thrust of the electric damper 6 can be reduced, and thus, the power consumption of the battery can be suppressed.

[0076] The suspension main body 100 shown in the above embodiment uses the magnetic force generated by the energization of the coil 23 to open and close the shutter members 41 and 46, thereby switching to operate either the electric damper 6 or the hydraulic damper 7. Accordingly, the influence on the riding comfort during normal operation can be reduced.

[0077] This will be further described. Figure 12 It is a diagram for explaining the thrust (contraction side) generated by the electric damper 6 when the electric damper 6 and the hydraulic damper 7 operate simultaneously. Figure 13 It is a diagram for explaining the thrust (contraction side) generated by the electric damper 6 when the electric damper 6 operates alone. As Figure 12 shown, in the state where both the electric damper 6 and the hydraulic damper 7 operate during normal operation, it sometimes acts in the following manner. When the rod 11 of the suspension main body 10 contracts, the damping force of the hydraulic damper 7 and the reaction force of a spring (not shown) provided on the suspension main body 100 interfere with the thrust generated by the electric damper 6. In this case, the actual thrust generated by the electric damper 6 decreases, and the riding comfort during normal operation may be affected. In response to this, as Figure 13 shown, in the state where only the electric damper 6 operates alone (ON), even if the thrust generated by the electric damper 6 is the same as that in Figure 12 , the actual thrust generated will be larger than that in Figure 12 . Therefore, by operating the electric damper 6 alone during normal operation, the influence on the riding comfort can be reduced.

[0078] However, the suspension main body 100 is configured to be able to open and close the shutter members 41 and 46 without relying on the energization of the coil 23, and thus, it can also be configured to use both the operation of the electric damper 6 and the operation of the hydraulic damper 7.

[0079] This will be further described. Figure 14 It is a diagram for explaining the actual thrust (extension side) generated by the electric damper 6 when the electric damper 6 operates alone. Figure 15This is a diagram showing the actual thrust (extension side) generated by the electric damper 6 when both the electric damper 6 and the hydraulic damper 7 are in the operating (ON) state. As Figure 14 shown, when the electric damper 6 is operating (ON) alone, the force required for shock absorption when the rod 11 extends is almost equal to the actual thrust generated by the electric damper 6. However, when the electric damper 6 and the hydraulic damper 7 are operating (ON) simultaneously, as Figure 15 shown, when the thrust directions of the electric damper 6 and the hydraulic damper 7 are the same, the damping force of the hydraulic damper 7 is utilized for the thrust generated by the electric damper 6, and the hydraulic damper 7 can assist the thrust of the electric damper 6. Accordingly, the actual thrust generated by the electric damper 6 can be reduced, and thus miniaturization of the suspension main body 100 can be achieved.

[0080] In the above embodiment, an oil-pressure type damper was cited as an example of the hydraulic damper 7, and the oil-pressure type damper can be a semi-active damper whose damping force can be arbitrarily changed. For example, Figure 16A is a damping force diagram showing a semi-active damper alone. In this case, in the suspension device 1 having the semi-active damper with such characteristics and the electric damper 6, by combining with Figure 10A the characteristics of the electric damper 6 shown, the characteristics shown in Figure 16B are obtained. According to the detection result of the road surface condition detection unit 200, the operation / non-operation of the semi-active damper can be appropriately controlled to maximize the performance of each damper.

[0081] In addition, Figure 17 as shown in the chart of, the electric damper 6 can also be configured to generate a damping force at the central part of the extension / contraction operation range and a relatively small damping force at the end of the operation range, and the hydraulic damper 7 can also be configured to generate a relatively small damping force at the central part of the contraction / extension operation range and a relatively large damping force at the end of the operation range.

[0082] Reference Numerals

[0083] 1 Suspension Device

[0084] 6 Electric Damper

[0085] 7 Hydraulic Damper

[0086] 200 Road Surface Condition Detection Unit

[0087] 300 Control Unit

Claims

1. A suspension device for a vehicle, comprising: An electric damper that operates with electricity; A hydraulic damper that operates with hydraulic pressure; A road surface condition detection unit that detects the road surface condition in front of the vehicle's tires; and A control unit that, based on the detection result of the road surface condition detection unit, determines whether the electric damper and the hydraulic damper can operate separately, and controls the ON / OFF of the respective operations of the electric damper and the hydraulic damper. The road surface condition detection unit processes the detection information of the road surface condition and generates information on the size of the convex portion of the road surface as information on the quantitative road surface condition. The control unit compares the information on the size of the convex portion of the road surface with a preset specified threshold value to determine whether the size of the convex portion of the road surface exceeds the threshold value.

2. The suspension device for a vehicle according to claim 1, wherein The control unit controls in the following manner: when it is determined that the road surface condition detected by the road surface condition detection unit exceeds a specified threshold value that can be handled by the electric damper alone, the hydraulic damper is operated.

3. The suspension device for a vehicle according to claim 1, wherein The control unit controls in the following manner: in at least any one of the cases where the vehicle is in an energy-saving mode, where a command cannot be output due to a failure of the control unit, and where the suspension device cannot be electrically controlled, the hydraulic damper is operated.

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