Damping force of variable shock absorbers

Abstract

A reduction in the speed of a height rise of the vehicle due to self-pumping is suppressed under the influence of a damping force of a damping force generating unit.A damping force variable shock absorber 150 includes a damping force variable mechanism 200 including a damping force generating unit 250, a damping force variable actuator 220, and a damping force control unit 210 configured to control an operation of the damping force variable actuator, and a vehicle height control mechanism 100 including a self-pumping mechanism 69 configured to pressurize hydraulic oil and urge a spring 60 using vibration caused by travel of a vehicle as a driving force, a vehicle height variable actuator 76 configured to switch a flow path of the self-pumping pressurized hydraulic oil, and a vehicle height control unit 110 configured to control an operation of the vehicle height variable actuator.The damping force control unit 210 performs process-by-process variable control of the damping force in which a damping force in a pressing operation of the spring 60 during a period in which a vehicle height rises is set to be weaker than a damping force during a period in which the vehicle height does not rise.

Description

TECHNICAL FIELD

[0001] The present invention relates to a damping force variable shock absorber. STATE OF THE ART

[0002] Fig. 2 and Fig. 5 of Patent Literature 1 shows a vehicle height adjusting device that can perform vehicle height change by self-pumping and can also adjust a damping force by a control valve with a magnet.

[0003] Furthermore, in paragraph

[0014] of Patent Literature 2, it is described that "even if the vehicle height deviates from a reference position during vehicle height change, a damping force is set larger than a damping force in the case where the vehicle height change is not performed, and therefore, the occurrence of a stop limiter or a rebound limiter can be prevented with a simple configuration and ride comfort can be improved." CITATION LISTPATENT LITERATURE Patent literature 1: WO2021 / 044552A Patent Literature 2: JP2007-245956A SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0004] Investigations by the present inventors have revealed the following problem: a vehicle height adjusting device operated by self-pumping is affected by a damping force of a damping force generating unit, and the speed of a vehicle height rise due to self-pumping may decrease.

[0005] Patent Literature 1 does not address this problem. Patent Literature 2 merely discloses a method for preventing the vehicle height from remaining low when carrying a large number of passengers or a large amount of cargo. Patent Literature 2 does not address the above-described problem of vehicle height adjustment using self-priming pumps.

[0006] The object of the present invention is to provide a damping force variable shock absorber capable of suppressing a reduction in the speed of a vehicle height rise due to self-pumping under the influence of a damping force of a damping force generating unit. SOLUTION TO THE PROBLEM

[0007] As a result of intensive research, the present inventors discovered that a reduction in speed with respect to a vehicle height increase due to self-pumping can be suppressed and steering stability can be improved by variably controlling a damping force in a pushing and pulling action of a spring during the vehicle height change due to self-pumping. The present invention was achieved based on this finding.

[0008] The present disclosure is described below.

[0009] According to one aspect of the present disclosure, there is provided a damping force variable shock absorber (150) comprising: a damping force variable mechanism (200) having a damping force generating unit (250), a damping force variable actuator (220), and a damping force control unit (210) configured to control an operation of the damping force variable actuator; and a vehicle height control mechanism (100) having a self-pumping mechanism (69) configured to pressurize hydraulic oil and press a spring (60) using vibration caused by the travel of a vehicle as a driving force, a vehicle height variable actuator (76) configured to switch a flow path of the self-pumping pressurized hydraulic oil, and a vehicle height control unit (110) configured to control an operation of the vehicle height variable actuator, wherein the damping force control unit (210) performs process-by-process variable damping force control in which a damping force in a pressing operation of the spring during a period in which a vehicle height increases by the vehicle height control mechanism (100) is set to be weaker than a damping force in the pressing operation of the spring (60) during a period in which the vehicle height does not increase. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0010] According to the present invention, it is possible to provide the damping force variable shock absorber capable of suppressing the reduction of a vehicle height rising speed due to self-pumping under the influence of the damping force of the damping force generating unit. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] Fig. 1 is a diagram showing an example of a configuration of a damping force variable shock absorber with a vehicle height adjustment function and an example of a hydraulic oil flow. [ Fig. 2] Fig. 2 shows a diagram showing the hydraulic oil flow for each of the Fig. 1 regarding increasing, maintaining and decreasing the vehicle height. [ Fig. 3] Fig. 3 is a diagram showing an example of hydraulic oil flow and a damping force generated when process-by-process variable control of the damping force is performed to variably control the damping force when a vehicle height increases by self-pumping. [ Fig. 4] Fig. Figure 4 is a graph showing the relationship between the opening degree of the throttle valve of a flow control valve and the damping force. [ Fig. 5] Fig. Figure 5 is a graph showing the difference in the rising speed of a jack when the damping force is set to a weak level or the damping force is set to a strong level and when the process-wise variable control of the damping force is not performed. [ Fig. 6] Fig. 6 is a characteristic diagram based on a Lissajous curve showing a change in damping force with respect to a stroke length when the damping force is set to the strong level and the process-by-process variable control of the damping force is not performed. [ Fig. 7] Fig. Figure 7 is a graph showing the difference in the rising speed of the jack when the damping force is set to the weak level or the damping force is set to the strong level and when the process-wise variable control of the damping force is performed. [ Fig. 8] Fig. Figure 8 is a characteristic diagram based on a Lissajous curve showing a change in damping force with respect to stroke length in the case where the damping force is set to the strong level and the process-wise variable control of the damping force is performed. [ Fig. 9] Fig. Figure 9 is a diagram showing an example of process-by-process variable control of the damping force of an override method. [ Fig. 10] Fig. Figure 10 is a diagram showing an example of process-by-process variable control of the damping force of a differential subtraction method. [ Fig. 11] Fig. 11 is a side view of a two-wheeled vehicle equipped with a damping force variable shock absorber that Fig. 1 has the function shown for changing the vehicle height. DESCRIPTION OF THE EMBODIMENTS

[0011] Embodiments of the present invention will be described below with reference to the accompanying drawings. The embodiments illustrated in the accompanying drawings are examples of the present invention, and the present invention is not limited to the embodiments. <Beispiel 1>

[0012] In the following description, the term "damping force variable shock absorber" is used, but it can also be referred to as a damping force variable shock absorbing unit, damping force variable damper, hydraulic damper or simply as a damper.

[0013] Before describing a detailed configuration of the damping force variable shock absorber, an overall configuration of a two-wheeled vehicle equipped with the damping force variable shock absorber will be described with reference to Fig. 11 described. Fig. 11 is a side view of the two-wheeled vehicle equipped with the damping force variable shock absorber and a Fig. 1 has the vehicle height adjustment function shown.

[0014] In the following description, front and rear refer to the front and rear relative to the vehicle's direction of travel. Furthermore, Vo represents a front direction, Hi represents a rear direction, TOP represents an upper direction, and DOWN represents a lower direction.

[0015] In Fig. 11, a motorcycle 1 includes a front wheel 2 which is a wheel at a front side, a rear wheel 3 which is a wheel at a rear side, and a vehicle body 10 having a vehicle body frame 11, a throttle grip 12, an engine 13, and others, which form a frame of the motorcycle 1.

[0016] The motorcycle 1 includes a front fork 19 as a front suspension portion connecting the front wheel 2 and the vehicle body 10 to each other, on the left and right sides of the front wheel 2, respectively. Furthermore, the motorcycle 1 includes a rear suspension 22 as a rear suspension portion connecting the rear wheel 3 and the vehicle body 10 to each other, on the left and right sides of the rear wheel 3, respectively.

[0017] The rear suspension 22 includes a body-side fastening element 20, a wheel-side fastening element 25 and a spring 24. In Fig. 11 only the front fork 19 and the rear suspension 22 of the left side are shown.

[0018] The front fork 19 and the rear suspension 22 are each an electronically controlled hydraulic suspension, and each of them is equipped with the damping force variable shock absorber according to the present invention.

[0019] Although not shown, the throttle grip 12 has a built-in switch portion. For example, when a driver rotates a predetermined portion of the throttle grip 12 in a predetermined direction, the switch portion is turned on to generate a control current, and the control current is sent to a vehicle height control mechanism to be described later to adjust a vehicle height. During the vehicle height change, the vehicle body 10 rises and falls while maintaining the horizontality of the vehicle body 10 with respect to a road surface G.

[0020] The control current may also be sent to a damping force control unit in a manner other than that described above, so that a damping force of the hydraulic damper can be variably controlled (described later).

[0021] Next, Fig. 1. Fig. Figure 1 is a diagram showing an example configuration of the damping force variable shock absorber with the vehicle height adjustment function and an example hydraulic oil flow. The hydraulic oil flow includes a hydraulic oil flow due to self-pumping when the vehicle height increases and a hydraulic oil flow that absorbs the shock of vibration caused by an external force when the vehicle height increases.

[0022] The damping force variable shock absorber 150 includes a vehicle height control mechanism 100 and a damping force variable mechanism 200.

[0023] The vehicle height control mechanism 100 includes a spring 60, a jack 62, a jack position sensor 61, a jack chamber 64, hydraulic check valves 70 and 86 as check valves, a solenoid valve 76, a storage chamber 84 that stores the hydraulic oil, and a pump chamber 66 in which a rod 68 is provided.

[0024] The spring 60 may also be referred to as a helical spring or simply a coil. One end of the spring 60 is installed in contact with a reference surface 51.

[0025] The rod 68 of the pump chamber 66 moves up and down or expands and contracts due to the vibration caused by the traveling of the vehicle, pressurizing the hydraulic oil to move the hydraulic oil. In this specification, a pressurizing operation of the hydraulic oil using vibration due to traveling as a driving force is referred to as self-pumping. Through self-pumping, it is possible to pressurize and move the hydraulic oil by using the vibration caused by the traveling of the vehicle as an energy source, even when there is no dedicated electrical power source. The pump chamber 66 and the rod 68 constitute a self-pumping mechanism 69. One end of the rod 68 is installed in contact with the reference surface 51.

[0026] The solenoid valve 76 is a type of electromagnetic switching valve that determines a flow path of the hydraulic oil. The opening and closing of a first flow path 80 and a second flow path 82 are controlled by variably controlling the current flowing through the built-in solenoid valve. The solenoid valve 76 functions as a vehicle height-variable actuator.

[0027] A vehicle height control unit 110 includes a vehicle height variable actuator drive unit 112. The vehicle height variable actuator drive unit 112 supplies a control current whose current intensity is adjusted to the solenoid valve 76 as the vehicle height variable actuator. This control current can also be referred to as a first control signal S1.

[0028] A detection signal of a wheel speed sensor 114 and a lifter position detection signal of the lifter position sensor 61 are supplied to the vehicle height control unit 110.

[0029] On the other hand, the damping force variable mechanism 200 includes a hydraulic damper 230, a flow control valve as a damping force variable actuator, namely, for example, an electromagnetic proportional throttle valve 220, and a damping force control unit 210 that controls an operation of the electromagnetic proportional throttle valve 220.

[0030] The electromagnetic proportional throttle valve 220 and the hydraulic damper 230 form a damping force generating unit 250.

[0031] In the electromagnetic proportional throttle valve 220, the opening degree of the throttle valve is changed in proportion to the current flowing through a proportional solenoid (not shown), and the flow rate of the hydraulic oil can be continuously changed.

[0032] The damping force control unit 210 includes a damping force-variable actuator drive unit 212. The damping force-variable actuator drive unit 212 supplies a control current whose current intensity is adjusted to the proportional magnet of the electromagnetic proportional throttle valve 220 as the actuator. This control current can also be referred to as a second control signal S2. The control current continuously changes, for example, the throttle opening degree of the electromagnetic proportional throttle valve 220, thus variably controlling the damping force.

[0033] The damping force control unit 210 is supplied with detection signals from a wheel speed sensor 214 and an acceleration sensor 216, as well as a detection signal from a stroke sensor 218 which detects the stroke of the hydraulic damper 230.

[0034] The hydraulic damper 230 includes a damper tube 233, a piston 240, a piston rod 242, an upper oil chamber 232, and a lower oil chamber 234. One end of the piston rod 242 is connected to the piston 240, and the other end of the piston rod 242 is installed in contact with the reference surface 51.

[0035] When the piston 240 moves upward and the upper oil chamber 232 is compressed, the hydraulic oil flows from the damper tube 233 into the lifter chamber 64, and the spring 60 is compressed.

[0036] When the piston 240 moves downward and the lower oil chamber 234 is compressed, the hydraulic oil flows from the lift chamber 64 into the damper tube 233, the hydraulic oil flows into the damper tube 233, and the spring 60 extends.

[0037] Piston 240 is equipped with a flow path consisting of a check valve 243 and a throttle valve 245, in other words, a first opening, and a flow path consisting of a throttle valve 247 and a check valve 249, in other words, a second opening. By appropriately adjusting the throttle valves 245 and 247, the damping force characteristics of the hydraulic damper can be adjusted.

[0038] In each of the throttle valves 245 and 247, a throttle adjusting unit capable of adjusting a throttle strength may be provided, and the damping force can be variably adjusted by the driver manually operating the adjusting unit.

[0039] The damping force control unit 210 and the vehicle height control unit 110 can independently perform respective control operations in a state where there is no increase in the vehicle height by self-pumping.

[0040] On the other hand, in a state where there is a rise in vehicle height due to self-surge, the damping force control unit 210 and the vehicle height control unit 110 can perform cooperative control by mutually linking variable damping force control and vehicle height control. Cooperative control can be referred to, for example, as a relationship control in which an output result of one control unit changes adaptively according to a state of another control unit.

[0041] For example, as described later, the damping force control unit 210 performs process-by-process variable control of the damping force to change the damping force value as the vehicle height rises. A timing of this control operation is preferably synchronized with a timing for variable control of the vehicle height performed by the vehicle height control unit 110, that is, with a timing of a switching operation of the flow path of the solenoid valve 76, which is an electromagnetic switching valve. Therefore, it is preferable that the control units 110 and 210 perform the control operations synchronously with each other by synchronizing the timings.

[0042] In this case, the vehicle height control unit 110 may, for example, transmit a timing signal as control signal S3 to the damping force control unit 210, and the damping force control unit 210 may determine a start timing for the process-by-process variable damping force control based on the received timing signal.

[0043] During the vehicle height rise, the vehicle height control unit 110 may calculate a speed of the vehicle height rise based on the detection signal of the lifter position sensor 61 and transmit the calculation result to the damping force control unit 210 as a control signal S3, and the damping force control unit 210 may appropriately change a switching cycle of the damping force in the process-by-process variable control of the damping force based on the received information on the speed of the vehicle height rise.

[0044] It can be assumed that an abnormality occurs during vehicle height ascent, disrupting the movement of the piston 240 of the damping force generating unit 250. In such a case, the damping force control unit 210 can communicate a signal to the vehicle height control unit 110 to notify the abnormality in the form of the control signal S4. In response, the vehicle height control unit 110 can also perform cooperative operations such as temporarily stopping a vehicle height raising operation and switching to a vehicle height holding operation.

[0045] Cooperative operation is an example, and the content of cooperative control is not limited to the cooperative operation described above.

[0046] The damping force control unit 210 and the vehicle height control unit 110 perform cooperative control in cooperation with each other so that the timing of the respective controls is consistent, enabling efficient and stable vehicle height adjustment. When an abnormality occurs, both control units work together to respond to it jointly, thereby achieving a faster return from the abnormal state to normal.

[0047] Next, the operation of the individual units during increasing vehicle height and the hydraulic oil flow are described. Fig. 1, the hydraulic oil flow is represented by arrows of a solid line, a dashed line and a dotted line.

[0048] When the power supply of a vehicle, e.g., a motorcycle, is turned on, the vehicle height-variable actuator drive unit 112 supplies a low current in the form of a first control signal S1 to the solenoid valve 76. The low current is selected from a selection of control currents, e.g., a selection of three levels. Accordingly, the first flow path 80 in the solenoid valve 76 is closed, and the vehicle height can be raised.

[0049] When the vehicle is moving and the self-pumping is initiated due to unevenness of the road surface, the hydraulic oil is pressurized to open the check valve 70, and the hydraulic oil moves from the pump chamber 66 to the jack chamber 64, as indicated by a solid line arrow LE.

[0050] Accordingly, the jack 62 moves downward, and a length of the spring 60 is shortened. The shortening of the length of the spring 60 results in an increase in the reaction force of the spring 60 and an increase in the force against a load applied to the vehicle body 10, so that the vehicle height increases.

[0051] In this way, the spring 60 is compressed by self-pumping. However, the spring 60 constantly vibrates slightly due to vibration during driving, regardless of the compression by self-pumping. To absorb the impact caused by the vibration, the hydraulic oil moves according to the vibration, and the impact is absorbed by the electromagnetic proportional throttle valve 220 and the hydraulic damper 230.

[0052] The electromagnetic proportional throttle valve 220 dampens the impact by restricting the movement of the hydraulic oil through the throttle. Furthermore, the hydraulic damper 230 dampens the impact by moving the piston 240 in the up-down direction, that is, by restricting the movement of the hydraulic oil through the throttle of the throttle valves 243 and 249, which form openings in the piston 240.

[0053] When the flow rate of the movable hydraulic oil is large, the force that reduces the impact effect of the vibration of the spring 60 and makes the vibration of the spring 60 subside becomes weak. Consequently, the damping force becomes weak, and the vibration lasts for a long time.

[0054] When the flow rate of the moving hydraulic oil is small, the damping force becomes strong and the vibration decays quickly.

[0055] Ride comfort varies depending on the magnitude of the damping force. When the damping force is large, the energy that causes the hydraulic oil to slide and move against the inner wall of the pump chamber during self-pumping tends to decrease. Therefore, the damping force generated by the variable-damping damper must be appropriately adjusted, taking into account the rate of vehicle height rise due to self-pumping.

[0056] When the spring 60 is compressed by the vibration, a flow LD1 of hydraulic oil is generated, which Fig. 1 is shown by a dashed line. In this case, the hydraulic oil is forced out of the damper tube 233 of the hydraulic damper 230 and moves to the siphoning chamber 64 via the electromagnetic proportional throttle valve 220 and the check valves 86 and 70. A flow LD3 of hydraulic oil is generated in the damper tube 233, indicated by a dashed line arrow.

[0057] When the spring 60 is extended by the vibration, a flow LD2 of hydraulic oil is generated, which Fig. 1 is shown by a dashed line. In this case, the hydraulic oil is forced out of the siphoning chamber 64 and moves via the second flow path 82 of the solenoid valve 76, the accumulator chamber 84, and the electromagnetic proportional throttle valve 220 to the upper oil chamber 232 of the hydraulic damper 230. A hydraulic oil flow LD4, indicated by a dashed line arrow, is generated in the damper tube 233.

[0058] Next, Fig. 2. Fig. 2 is a diagram showing a flow of hydraulic oil corresponding to each of the Fig. 1 corresponds to the processes of increasing, maintaining and decreasing the vehicle height. In Fig. 2 are the Fig. 1 identical features are designated by the same reference numerals. Since the vehicle height increase was described above, the operations for maintaining and decreasing the vehicle height are described here.

[0059] First, the process of maintaining the vehicle height will be described. When the lifter 62 reaches a predetermined target position, the lifter position sensor 61 detects this arrival and sends a detection signal to the vehicle height control unit 110. Accordingly, the vehicle height control unit 110 supplies an average current of the control currents from the three-stage selection as the first control signal S1 to the solenoid valve 76.

[0060] In this case, as indicated by a dashed line arrow LG, the hydraulic oil moves through the first flow path 80, the accumulator chamber 84, and the check valve 86, but the same amount of hydraulic oil discharged from the pump chamber 66 is returned to the pump chamber 66, and the amount of hydraulic oil in the lift chamber 64 does not change. Accordingly, the vehicle height is maintained.

[0061] When the vehicle height is lowered, the vehicle height variable actuator drive unit 112 supplies a high current of the control currents from the selection of the three stages as the first control signal S1 to the solenoid valve 76.

[0062] In this case, the hydraulic oil moves, as indicated by a dashed arrow LF, from the siphoning chamber 64 to the pumping chamber 66 via the second flow path 82 of the solenoid valve 76, the accumulator chamber 84 and the check valve 86. Accordingly, the spring 60 is stretched and thus the length of the spring 60 is increased.

[0063] Increasing the length of the spring 60 means reducing the reaction force of the spring 60, and since the force against the load exerted on the vehicle body 10 is weakened, the vehicle height is reduced.

[0064] Next, Fig. 3. Fig. Figure 3 is a diagram showing an example of the hydraulic oil flow and damping force generated when process-by-process variable damping force control is performed to variably control the damping force when the vehicle height rises by self-pumping. Fig. 3, the same parts as in the above drawings are marked with the same reference numerals.

[0065] As the vehicle travels, the vehicle body moves up and down due to the unevenness of the road surface, and accordingly, an external force in a compression direction that pushes and compresses the spring 60 and an external force in a tension direction that pulls and extends the spring 60 are alternately generated. In other words, a compression and tension action occur alternately with respect to the vibration due to the external force of the spring 60.

[0066] In Fig. 3, the external force in the compression direction is called C-force (compression force) and the damping force for damping the external force in the compression direction is called Dum-C-force (damping C-force).

[0067] The external force in the tensile direction is called E-force (elongation force), and a damping force to dampen the external force in the tensile direction is called Dum-E-force (damping E-force).

[0068] In the following description, the damping force Dum-C-Force for damping the external force in the compression direction is referred to as the damping force during the compression process of the spring, and the damping force Dum-E-Force for damping the external force in the tension direction is referred to as the damping force during the tension process of the spring.

[0069] In Fig. In Figure 3, the C-force and the E-force are represented by solid arrows. The Dum-C force and the Dum-E force are indicated by white arrows.

[0070] The Fig. The flow direction of the hydraulic oil shown in Figure 3 is the same as in Fig. 1. Fig. 3 differs from Fig. 1 in that the process-wise variable control of the damping force is carried out to variably control the damping force as the vehicle height increases.

[0071] As described above, the driver can adjust the strength of the damping force generated by the damping force variable mechanism 200 according to his or her preference by means of an electronic control or by manual adjustment.

[0072] The damping force of the damping force generating unit 250 can be set to at least a first level where the damping force is relatively weak and a second level where the damping force is relatively strong. When the damping force is at the first level, a so-called soft ride comfort is achieved, and when the damping force is at the second level, a so-called hard ride comfort is achieved.

[0073] According to studies by the present inventors, when the damping force is set to, for example, the second stage where the damping force is relatively strong, the vibration of the spring 60 due to the unevenness of the road surface quickly decays, thus it is clear that the vibration serving as the driving force for the vehicle height rise by self-pumping tends to be insufficient, so that the speed of the vehicle height rise may decrease.

[0074] In order to suppress a reduction in the speed of the vehicle height rise, in an example of Fig. 3 the process-wise variable control of the damping force is carried out.

[0075] As described above, the damping force of the damping force generating unit 250 can be set to at least the first level at which the damping force is relatively weak and the second level at which the damping force is relatively strong, and the damping force control unit 210 can perform the process-by-process variable control of the damping force when the damping force of the damping force generating unit 250 is set to the first level or the second level and the vehicle height rises by self-pumping.

[0076] In the following description, it is assumed that the damping force is set to the second level, that is, the relatively strong level, and that the vehicle is moving in this case and self-pumping control of the vehicle height rise begins.

[0077] This is because when the set damping force is at the relatively weak level, the vibration serving as the driving force for self-pumping is hardly suppressed excessively, and on the other hand, when the damping force is at the relatively strong level, the vibration tends to be suppressed excessively, and it is often necessary to take measures.

[0078] Through the process-by-process variable control of the damping force described later, the vibration, which is the driving force of self-pumping, is not excessively suppressed, and it is possible to improve the speed of the vehicle height rise or the steering stability.

[0079] However, this is only an example, and the present invention is not limited to this example. That is, even if the damping force is set to the first level, that is, the relatively weak level, process-by-process variable control of the damping force can be performed as needed.

[0080] In this case, for example, it is possible to prevent the amplitude of a vehicle height fluctuation in a state where the vehicle height comes close to a desired height and to achieve an effect of improving ride comfort.

[0081] In Fig. 3, the dashed arrow indicating the flow rate LD1 of the hydraulic oil during the pressing operation of the spring 60 is shown by a thick line, which means that the flow rate is large.

[0082] In other words, the fact that the flow rate of the hydraulic oil flow LD1 during the pressing process of the spring 60 is large means that the damping force Dum-C-Force generated by the hydraulic oil flow LD1 is set small. Fig. 3 briefly shows the length of the white arrow indicating the Dum-C force.

[0083] On the other hand, the flow rate of the flow LD2 of the hydraulic oil during the pulling operation of the spring 60 is the same as in Fig. 1 or less than the Fig. 1. In Fig. 3, the flow rate LD2 of the hydraulic oil is the same as in Fig. 1. In Fig. 3, the length of the white arrow indicating the Dum-E force is drawn long.

[0084] The reason why the damping force Dum-C-Force is set small during the compression process of the spring 60 is that the external force C-Force in the compression direction acts in the direction of compression of the spring 60 and is therefore an external force beneficial for improving the vehicle height rise due to self-pumping. This is because it is not advantageous to significantly reduce it from the perspective of improving the vehicle height rise rate.

[0085] Regarding the external force E-force in the traction direction, it can be said that from the point of view of improving the speed of the vehicle's height rise, it is advantageous to change the damping strength. However, since the change in the damping strength affects the ride comfort, in consideration of this point, the example of Fig. 3 the damping force Dum-E-Force is set so that it is the same regardless of whether the jack rises or not, that is, regardless of whether the vehicle height rises or not.

[0086] According to the process-by-process variable control of the damping force, the damping force Dum-C-Force during the pushing operation of the spring 60 is set to a small value, while the damping force Dum-E-Force during the pulling operation of the spring 60 is not changed, and therefore a compression-side damping force of the entire suspension can be made to be the same level regardless of whether the jack rises or not.

[0087] On the other hand, since the damping force Dum-C-Force is set to be small during the compression of the spring 60, the external force C-Force, which is beneficial for improving the vehicle height rise due to self-pumping, is not significantly reduced, and the vibration serving as the driving force of the self-pumping can be maintained to a certain extent. Accordingly, it is possible to suppress the decrease in the vehicle height rise rate.

[0088] As described above, the damping force variable shock absorber 150 includes the variable damping mechanism 200 having the damping force generating unit 250, the variable damping force actuator 220, and the damping force control unit 210 configured to control the operation of the variable damping force actuator, and the vehicle height control mechanism 100 having the self-pumping mechanism 69 configured to pressurize the hydraulic oil and compress the spring 60 using the vibration caused by the travel of the vehicle as the driving force, the vehicle height variable actuator 76 is configured to pressurize the flow path of the hydraulic oil by self-pumping, and the vehicle height control unit 110 is configured to control the operation of the vehicle height variable actuator.The damping force control unit 210 performs the process-by-process variable control of the damping force in which the damping force in the pressing operation of the spring 60 during a period in which the vehicle height is rising by the vehicle height control mechanism 100 is set to be weaker than the damping force in the pressing operation of the spring 60 during a period in which the vehicle height is not rising, that is, a damping force corresponding to a normal setting.

[0089] As a result, it is possible to achieve the ride comfort desired by the driver while maintaining an appropriate damping force. It is also possible to maintain a certain degree of vibration and ensure the required speed of vehicle height change by not excessively preventing the external force of vibration, which serves as the driving force of self-pumping. Furthermore, the effect of improving steering stability can also be achieved by reducing the difference in damping characteristics between a rising and a non-rising vehicle height. This will be described later.

[0090] Next, Fig. 4. Fig. Figure 4 is a graph showing the relationship between the throttle opening degree of the flow control valve and the damping force. Fig. 4 are equal parts as in Fig. 3 are marked with the same reference numbers.

[0091] A-1 in Fig. Figure 4 shows an example of the throttle opening degree of the flow control valve and an example of the damping force generated when self-surging occurs and the damping force is set to a weak level. As shown in Figures A-1-1 and A-1-2, the throttle opening degree of the flow control valve 220 is set large. The flow rates of the hydraulic oil streams LD1 and LD2 both increase. As shown in Figure A-1-3, the damping forces of the damping force Dum-C force during the pushing action of the spring 60 and the damping force Dum-E force during the pulling action of the spring 60 are both small.

[0092] A-2 in Fig. Figure 4 shows an example of the throttle opening degree of the flow control valve and an example of the damping force generated when self-surging occurs and the damping force is set to the strong level. As shown in Figures A-2-1 and A-2-2, the throttle opening degree of the flow control valve 220 is set small. The flow rates of the hydraulic oil streams LD1 and LD2 both decrease. As shown in Figure A-2-3, the damping forces of the damping force Dum-C force during the pushing action of the spring 60 and the damping force Dum-E force during the pulling action of the spring 60 are both large.

[0093] A-3 of Fig. Figure 4 shows an example of the throttle opening degree of the flow control valve and an example of the generated damping force when the self-pumping exists, the damping force is set to the strong level, and the process-by-process variable control of the damping force is performed.

[0094] As shown in A-3-1, during the compression action of the spring 60, the throttle opening degree of the flow control valve 220 is set to a large value, and the hydraulic oil flow rate LD1 increases. Accordingly, the damping force Dum-C-Force decreases.

[0095] As a result, the damping of the external force (C-force), which is beneficial for raising the vehicle height, is mitigated, and the vibration caused by the external force is retained to a certain extent. As a result, the vibration, which serves as the driving force for raising the vehicle height, is maintained without being excessively damped, and the decrease in the rate of vehicle height rise is mitigated.

[0096] On the other hand, when the spring 60 is pulled, as described above, the damping force Dum-E-Force is not changed when the spring 60 is pulled. As a result, the compression-side damping force of the entire suspension can be brought to a constant level regardless of whether the jack rises or not.

[0097] The opening degree of the throttle valve of the flow control valve 220 is set to a small value, and the hydraulic oil flow LD2 decreases. Accordingly, the damping force Dum-E-Force increases. As a result, the external force E-Force that prevents the vehicle from climbing is greatly reduced according to the initial damping force setting. This ensures the firm ride comfort desired by the driver.

[0098] In this way, it is possible to achieve the desired ride comfort and the desired speed of vehicle height rise. In other words, it is possible to achieve both ride comfort and the desired speed of vehicle height rise.

[0099] Next, Fig. 5. Fig. Figure 5 is a graph showing the difference in the rising speed of the jack when the damping force is set weakly or strongly and when the process-by-process variable control of the damping force is not performed.

[0100] In Fig. 5 The horizontal axis shows the elapsed time since the start of self-pumping, and the vertical axis shows the position of the jack.

[0101] A characteristic curve Q1 indicates a change in the position of the jack with respect to time when the damping force is set to the weak level and the process-wise variable control of the damping force is not performed. The characteristic curve Q1 corresponds to the example of A-1 in Fig. 4.

[0102] In the example given by the characteristic curve Q1, the position of the lifter reaches a target position TR at a time t1. Time t2 is a time corresponding to the maximum allowable time Tc. In the example given by the characteristic curve Q1, the position of the lifter reaches the target position TR within the allowable time Tc.

[0103] On the other hand, a characteristic curve Q2 indicates a change in the position of the jack with respect to time when the damping force is set to the strong level and the process-by-process variable control of the damping force is not performed. The characteristic curve Q2 corresponds to the example of A-2 in Fig. 4.

[0104] In the example given by characteristic curve Q2, the position of the lifter reaches the target position TR at time t3. In the example given by characteristic curve Q2, a longer time than the allowable time Tc is required for the position of the lifter to reach the target position TR. Accordingly, the position of the lifter must reach the target position within the allowable time Tc.

[0105] Next, Fig. 6. Fig. 6 is a characteristic diagram based on a Lissajous curve showing a change in damping force with respect to a stroke length when the damping force is set to the strong level and the process-by-process variable control of the damping force is not performed.

[0106] A characteristic curve Q10 indicates a characteristic curve when there is no increase in vehicle height due to self-pumping. A characteristic curve Q20 indicates a characteristic curve in which there is a increase in vehicle height due to self-pumping.

[0107] The damping force value of characteristic curve Q20 is significantly larger than the damping force value of characteristic curve Q10. In other words, during self-pumping, a shape of the Lissajous curve deviates from the normal shape. This is because during self-pumping, in addition to the normal external force applied to the spring, a jack-up force usually acts. Therefore, the external force obviously increases by the jack-up force or the reaction force. Accordingly, the generated damping force tends to be higher than the design value.

[0108] If the actual damping force deviates from the design value during self-pumping, the vehicle's steering stability will be affected, and it cannot be assumed that there will be no cases where the driver cannot operate the vehicle as intended or expected. Accordingly, it is necessary to prevent this deviation and bring the damping value set during self-pumping close to the design value.

[0109] Next, Fig. 7. Fig. Figure 7 is a graph showing the difference in the rising speed of the jack when the damping force is set to the weak level or the damping force is set to the strong level and when the process-wise variable control of the damping force is performed.

[0110] In Fig. 7 are the same parts as in Fig. 6 are designated by the same reference numerals. In Fig. 7, however, the characteristic curve Q2 is Fig. 6 is marked by a dashed line.

[0111] One in Fig. 7 shows a change in the position of the jack with respect to time when the damping force is set to the strong level and the curve described above with reference to the Fig. 3 and Fig. 4 described process-wise control of the damping force is carried out. The characteristic curve Q3 corresponds to the example of A-3 in Fig. 4.

[0112] As mentioned above with reference to the Fig. 3 and Fig. As described in Figure 4, when process-by-process variable damping force control is implemented, the damping force obtained by combining the respective damping forces in the compression and extension processes of the spring is reduced from an initially strong damping force to a medium damping force. As a result, vibration as the driving force of self-pumping is not excessively inhibited, and a certain degree of vibration is ensured.

[0113] Accordingly, in the example of characteristic curve Q3, the speed of the vehicle height increase due to self-pumping is improved compared to the example given by characteristic curve Q2.

[0114] In the example given by the characteristic curve Q3, the position of the lifter reaches the target position TR at a time t4. In other words, the lifter can reach the target position within the allowable time Tc. Accordingly, the Fig. The problem described in section 5 is solved and the performance of a self-pumping vehicle height increase is improved.

[0115] The Fig. The characteristic curve Q4 shown in Figure 7 indicates the time change of the position of the jack when the damping force is set to the weak level and the process-by-process control of the damping force is performed.

[0116] The characteristic curve Q4 corresponds to the Fig. 5 and described above. In the characteristic curve Q4, in a state where the position of the jack approaches the target position TR, that is, in a state after time t2, the amplitude fluctuation is prevented compared to the characteristic curve Q1. In other words, the amplitude of the vehicle height fluctuation can be prevented by process-by-process control of the damping force. Accordingly, it is possible to achieve the effect of improving ride comfort.

[0117] Next, Fig. 8. Fig. Figure 8 is a characteristic diagram based on a Lissajous curve showing a change in damping force with respect to the stroke length when the damping force is set to the strong level and the process-wise variable control of the damping force is performed.

[0118] A characteristic curve Q10 indicates a characteristic curve when no vehicle height rise occurs due to self-pumping. A characteristic curve Q30 indicates a characteristic curve when the vehicle height rise occurs due to self-pumping and the damping force is controlled process-by-process.

[0119] As above with reference to the Fig. 3 and Fig. 4, when the process-by-process variable control of the damping force is performed, according to the process-by-process variable control of the damping force, the damping force Dum-C-Force in the pushing process of the spring 60 is set to a small value, the damping force Dum-E-Force in the pulling process of the spring 60 is not changed, and therefore the pushing-side damping force of the entire suspension can be made to be at a level regardless of whether the jack rises or not.

[0120] Therefore, the value of the damping force of the characteristic curve Q30 becomes small during self-pumping, and the characteristic curve Q30 approaches the characteristic curve Q10 in the normal state.

[0121] In other words, in the example of characteristic curve Q30, the shape of the Lissajous curve is prevented from deviating from the normal form during self-pumping. This prevents the actual damping force from deviating significantly from the design value during self-pumping. Therefore, the vehicle's steering stability is improved, and the vehicle can be operated smoothly as intended or expected by the driver. <Beispiel 2>

[0122] Next, Fig. 9. Fig. Figure 9 is a diagram showing an example of process-by-process variable control of damping force in an override method. Fig. 9 shows a control during the vehicle height rise.

[0123] In the example of Fig. 9, the damping force control unit 210 includes a calculation unit 302 that calculates a control signal value of the electromagnetic proportional throttle valve 220 serving as a damping force variable actuator, in other words, the value of the control current, an override setting unit 304 that overrides the current control signal value with the calculated new control signal value when the control signal value is updated in the process-by-process variable control of the damping force, and the damping force variable actuator drive unit 212 that drives the damping force variable actuator 220 based on the control signal value read by the override setting unit 304.

[0124] In Fig. 9, a period from time t10 to time t11 is a tensile action period TA1 of the spring 60, a period from time t11 to time t12 is a compression action period TB1 of the spring 60, a period from time t12 to time t13 is a tensile action period TA2 of the spring 60, and a period from time t13 to time t14 is a compression action period TB2 of the spring 60. As described above, the damping force during the tensile action periods TA1 and TA2 is the same as the damping force when there is no rise in the vehicle height, and there is no change. During the compression action periods TB1 and TB2, the damping force is set to be weaker than the damping force when there is no rise in the vehicle height.

[0125] According to the configuration and a control method of Fig. 9, for example, a series of operations can be efficiently performed by using a storage device such as an overwrite register as an overwrite setting unit and setting a write / read timing for the storage device. The overwrite method has the advantage of being easy to set the timing. <Beispiel 3>

[0126] Next, Fig. 10. Fig. Figure 10 is a diagram showing an example of process-by-process variable control of the damping force of a differential subtraction method. Fig. 10 are equal parts as in Fig. 9 are marked with the same reference numbers.

[0127] In Fig. 10, the time period from time t10 to time t11 is the tensile action period TA1 of the spring 60, the time period from time t11 to time t12 is the compression action period TB1 of the spring 60, the time period from time t12 to time t13 is the tensile action period TA2 of the spring 60, and the time period from time t13 to time t14 is the compression action period TB2 of the spring 60. As described above, the damping force during the tensile action periods TA1 and TA2 is the same as the damping force when there is no increase in the vehicle height, and there is no change. During the compression action periods TB1 and TB2, the damping force is set to be weaker than the damping force when there is no increase in the vehicle height.

[0128] The damping force control unit 210 includes a calculation unit 404 that calculates a new control signal value by subtracting a second value, which is a constant value or a variable whose value changes depending on the situation, from a first value that serves as a reference when a control signal value of the electromagnetic proportional throttle valve 220 serving as a variable actuator of the damping force, in other words, the value of the control current, is updated.

[0129] The first value used as a reference can be, for example, a control signal value corresponding to the current damping value or a control signal value with a fixed value that has been set in advance.

[0130] When the second value is a variable, it is necessary to calculate the second value, which is a difference value, and therefore, a difference value calculation unit 402 is provided before the calculation unit 404. When the second value, which is the difference value, is a constant value, in other words, a fixed value, it is not necessary to obtain the second value by calculation, and therefore, the difference value calculation unit 402 is not necessary.

[0131] When timing adjustment is required, for example, a transmission control unit 405, such as a transmission gate with an output enable function, may be provided in a signal transmission path, and an output timing of the signal may be adjusted according to an output enable signal. Accordingly, precise timing control can be performed.

[0132] According to the configuration and a control method of Fig.10, it is possible to calculate the control signal value only by calculation without writing / reading to / from the storage device, and it is possible to further shorten the time required to obtain the control signal, making it possible to cope with high-frequency vibrations. The subtraction method has the advantage of being able to obtain the control signal value at high speed.

[0133] As described above, according to the examples of the present invention, it is possible to achieve an effect of appropriately adjusting the damping force to prevent an excessive increase in the damping force, realize good steering stability to improve ride comfort, and shorten the time required for vehicle height adjustment.

[0134] The present invention is not limited to the above description, and various modifications and applications are possible.

[0135] For example, the damping force control unit 210 may perform the process-by-process variable control of the damping force when the spring 60 is fully compressed.

[0136] As the spring 60 is compressed, the reaction force of the spring 60 changes, making it difficult to adjust the damping force, so that when the spring 60 is fully compressed, the damping force changes in a controlled manner, allowing for precise adjustment.

[0137] The reaching of the fully compressed state of the spring 60 can be detected, for example, by detecting the stroke direction of the spring 60 with an acceleration sensor or similar.

[0138] The damping force control unit 210 may change a control value of the damping force in the process-by-process variable control of the damping force depending on the vehicle speed of the vehicle or a stroke speed of the spring.

[0139] For example, since the speed of the vehicle height rise and the ride comfort due to self-pumping are affected by the vehicle speed and the stroke speed of the spring, both the speed of the vehicle height rise and the ride comfort can be achieved by optimizing the control amount of the damping force taking into account the vehicle speed and the stroke speed.

[0140] For example, when the vehicle speed increases rapidly, e.g., exceeds a predetermined value, or the lifting speed increases rapidly, e.g., exceeds a predetermined value, immediately after the vehicle starts traveling, if it is assumed that there are many vibrations useful for self-pumping, the degree of attenuation of the damping force in the pressing process of the spring can be reduced.

[0141] In the above description, the motorcycle was described as an example, but the present invention is also applicable to a three-wheeled vehicle, a four-wheeled vehicle, and the like. The type of vehicle is not limited.

[0142] As described above, according to the present invention, it is possible to provide the damping force variable shock absorber capable of suppressing the reduction in the speed of vehicle height rise due to self-pumping under the influence of the damping force of the damping force generating unit.

[0143] The present invention is not limited to the examples as long as the functions and effects of the invention are present. INDUSTRIAL APPLICABILITY

[0144] The present invention is suitable, for example, for an electronically controlled damping force variable shock absorber capable of performing the vehicle height adjustment of a motorcycle. REFERENCE SYMBOL LIST 1 vehicle (motorcycle) 2 front wheel 3 rear wheel 10 Body 11 Body frame 12 Throttle grip (throttle grip as a control unit with at least one built-in switch for controlling the damping force and one built-in switch for controlling the vehicle height) 13 Engine 19 Front fork (part of the front suspension) 20 body-side fastening element 22 Rear suspension (rear part of the suspension) 24 Spring (suspension spring) 25 wheel-side fastening element 60 spring 61 Lifter position sensor 62 lifters 64 lift chamber (lift oil chamber) 66 Pump chamber 68 Rod (rod for self-pumping, pump rod) 70, 86 Check valve (hydraulic check valve) 76 Solenoid valve (electromagnetic switching valve, vehicle height variable actuator) 84 storage chamber 100 Vehicle height control mechanism 110 Vehicle height control unit 112 Vehicle height variable actuator drive unit 114 Wheel speed sensor 150 Damping force variable shock absorber (damping force variable shock absorber unit, damping force variable damper, damper) 200 Damping force variable mechanism 210 Damping force control unit 212 Damping force variable actuator drive unit (execution unit for controlling the damping force) 214 Wheel speed sensor 216 Accelerometer 218 stroke sensor 220 Flow control valve (electromagnetic proportional throttle valve, damping force variable actuator) 230 hydraulic damper 250 Damping force generation unit 232 upper oil chamber (pressure-side oil chamber) 233 Damping tube 234 lower oil chamber (pull side oil chamber) 240 pistons 242 piston rod 243, 249 check valve 245, 247 throttle valve 302 Calculation unit (calculation unit for a control signal value corresponding to an attenuation value) 304 Setting unit (overwrite setting unit, storage device) 402 Calculation unit (calculation unit for calculating a difference value, calculation unit for a second value) 404 Calculation unit (calculation unit for calculating a control signal value by subtraction) 405 transmission unit (transmission gate or similar) QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2021 / 044552

[0003] JP 2007-245956A

[0003]

Claims

[1] A damping force variable shock absorber comprising a damping force variable mechanism comprising: a damping force generating unit; a damping force variable actuator; and a damping force control unit configured to control the operation of the damping force variable actuator; and a vehicle height control mechanism comprising: a self-pumping mechanism configured to pressurize hydraulic oil and urge a spring using vibration caused by travel of a vehicle equipped with the damping force variable mechanism as a driving force; a vehicle height variable actuator configured to switch a flow path of self-pressurized hydraulic oil; and a vehicle height control unit configured to control an operation of the vehicle height variable actuator, wherein the damping force control unit performs process-by-process variable control of the damping force in which a damping force in a pressing operation of the spring during a period in which a vehicle height is rising by the vehicle height control mechanism is set to be weaker than a damping force in the pressing operation of the spring during a period in which the vehicle height is not rising. [2] The damping force variable shock absorber according to claim 1, wherein the damping force control unit and the vehicle height control unit independently perform respective control operations in a state where there is no increase in the vehicle height due to self-pumping, and the damping force control unit and the vehicle height control unit connect a variable damping force control and a vehicle height control to each other to perform cooperative control in a state where there is an increase in vehicle height due to self-surging. [3] The damping force variable shock absorber according to claim 1, wherein a damping force of the damping force generating unit can be set to at least a first level at which the damping force is relatively weak and a second level at which the damping force is relatively strong, and the damping force control unit performs the process-by-process variable control of the damping force in a case where the damping force of the damping force generating unit is set to the first level or the second level and the vehicle height increases by self-pumping. [4] The damping force variable shock absorber according to claim 1, wherein the damping force control unit performs the process-by-process variable control of the damping force when the spring is fully compressed. [5] The damping force variable shock absorber according to claim 1, wherein the damping force control unit changes a control value of the damping force in the process-by-process variable control of the damping force depending on a vehicle speed of the vehicle or a stroke speed of the spring. [6] The damping force variable shock absorber according to claim 1, the damping force control unit comprising a calculation unit that calculates a control signal value of the damping force variable actuator; and an overwrite setting unit that overwrites a current control signal value with a calculated new control signal value when the control signal value is updated in the process-by-process variable damping force control. [7] The damping force variable shock absorber according to claim 1, the damping force control unit comprising: a calculation unit that calculates a new control signal value by subtracting a second value, which is a constant value or a variable whose value changes according to a situation, from a first value that serves as a reference when a control signal value of the damping force-variable actuator is updated in the process-by-process variable control of the damping force.

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