JP2009115301A - Shock absorber controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber providing a suitable damping force while restraining a device from enlarging and its cost from increasing. <P>SOLUTION: In a shock absorber controlling device, a flow passage 42a into which a working liquid flows is formed in a piston 42, and the piston causes the working liquid in a fluid chamber forward in the sliding direction to flow into the flow passage 42a and then to flow out to a fluid chamber backward in the sliding direction when it slides the interior of a cylinder 40. A first and second gears 50, 52 are provided in the flow passage 42a so as to rotate by a flow of the working liquid in the flow passage 42a. A motor generator 19 generates by utilizing rotating motion of the first and second gears 50, 52. Generated current is supplied to a variable resistor 20, thereby braking force being applied to the first and second gears 50, 52. An ECU 30 controls the damping force applied to the piston 42 by varying the resistance of the variable resistor 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a shock absorber control device, and more particularly to a shock absorber control device that controls a damping force when a shock absorber expands and contracts.

There is known a shock absorber that generates a damping force when a piston slides inside a cylinder filled with hydraulic fluid such as oil. As such a shock absorber, for example, a vibration damping device that consumes electric energy generated according to the flow of the working fluid of the shock absorber outside the cylinder has been proposed (see, for example, Patent Document 1). In order to realize an appropriate damping force, for example, a shock absorber has been proposed in which an inclined surface facing the leaf valve is provided in the vicinity of the concave portion of the valve seat (see, for example, Patent Document 2).
JP 59-187124 A JP-A-8-135712

  In the technique described in Patent Document 1 described above, it is necessary to draw hydraulic fluid in the cylinder of the shock absorber to the outside of the shock absorber. For this reason, there exists a possibility that size reduction of an apparatus and reduction of cost may become difficult. Further, in the technique described in Patent Document 2 described above, the damping force is minute in a region where the piston sliding speed is low. If only a small damping force can be obtained in a region where the piston sliding speed is low in the shock absorber, the steering stability of the vehicle may be affected, and the vehicle may be wobbled. For this reason, development of a new shock absorber capable of obtaining an appropriate damping force even in such a region is required.

  Therefore, the present invention has been made to solve the above-described problems, and its object is to provide a shock absorber capable of obtaining an appropriate damping force while suppressing an increase in size and cost of the device. There is to do.

  In order to solve the above-described problems, a shock absorber control device according to an aspect of the present invention is a shock absorber control device that controls a damping force when a shock absorber expands and contracts. The fluid in the fluid chamber at the front in the moving direction flows into the flow channel and flows out into the fluid chamber at the rear in the sliding direction. Provided to the piston by changing the braking force applied to the flow resistance member, the flow resistance member that generates the flow resistance between the hydraulic fluid, the braking means that applies the braking force to the rotating flow resistance member, and the flow resistance member Damping force control means for controlling the damping force.

  According to this aspect, since the flow resistance member for generating electric power by the flow of the hydraulic fluid is disposed inside the piston, the size of the apparatus is increased as compared with the case where the piping for flowing the hydraulic fluid is routed outside the shock absorber. And increase in cost can be suppressed. Further, by applying a braking force to the flow resistance member, a large damping force can be obtained even in a region where the piston slides at a low speed. For this reason, it is possible to improve the steering stability of the vehicle and to suppress the feeling of wobbling of the vehicle.

  The braking means has a power generation means for generating electric power by utilizing the rotational motion of the flow resistance member, and a variable resistance connected to the power generation means, and the generated current is supplied to the variable resistance so that the flow resistance member The braking force may be applied, and the damping force control means may control the damping force applied to the piston by changing the resistance value of the variable resistance to change the braking force applied to the flow resistance member.

  According to this aspect, a mechanism for applying a braking force to the flow resistance member can be simplified. Further, the damping force applied to the piston can be controlled by a simple method of changing the resistance value of the variable resistor, and the damping force can be easily controlled.

  The power generation means may be disposed outside the cylinder. According to this aspect, it is possible to avoid arranging the power generation means inside the cylinder filled with the hydraulic fluid, and the maintenance of the power generation means can be facilitated.

  The flow resistance member rotates in the third direction by the flow of the working fluid in the flow path when the piston slides in the first direction inside the cylinder, and the piston moves in the third direction opposite to the first direction in the cylinder. The variable resistance is rotated in the fourth direction opposite to the third direction by the flow of the hydraulic fluid in the flow path when sliding in the two directions, and the variable resistance is a first variable resistance and a second variable resistance connected to the power generation means. And a first diode that prevents the current generated by utilizing the rotational motion of the flow resistance member in the fourth direction from being supplied to the first variable resistor, and the rotational motion of the flow resistance member in the third direction. And a second diode that prevents supply of the generated current to the second variable resistor. The damping force control means may change the resistance value of the first variable resistor and the resistance value of the second variable resistor.

  There is a high possibility that the shock absorber is given a larger impact in the direction of contraction than in the direction of expansion, for example, when the wheel rides on the convex part. According to this aspect, it is possible to control the damping force when the piston slides in the first direction by changing the resistance value of the first variable resistance, and by changing the resistance value of the second variable resistance. The damping force when the piston slides in the second direction can be controlled. Therefore, the damping force when the piston slides in the first direction and the damping force when the piston slides in the second direction can be individually controlled. Therefore, it is possible to cause the shock absorber to generate an appropriate damping force according to the difference between the impact applied in the extending direction and the impact applied in the contracting direction.

  The piston permits the flow of the working fluid to the first passage and the second passage through which the working fluid flows, and the second passage when the piston slides in the first direction inside the cylinder, And a check valve that prevents the flow of hydraulic fluid into the second flow path when the piston slides in the cylinder in the second direction opposite to the first direction. The flow resistance member has a first flow resistance member and a second flow resistance member that rotate together, and the first flow resistance member is provided in the first flow path so as to rotate due to the flow of the working fluid in the first flow path. The second flow resistance member is provided in the second flow path so as to rotate by the flow of the working fluid in the second flow path, and the braking means applies a braking force to the first flow resistance member and the second flow resistance member. Also good.

  According to this aspect, when the piston slides in the first direction, the hydraulic fluid can flow in both the first flow path and the second flow path, and when the piston slides in the second direction. In addition, the hydraulic fluid can flow only in the first flow path. For this reason, the rotational speed of the flow resistance member can be made different between when the piston slides in the first direction and when the piston slides in the second direction, and the piston slides in the first direction. It is possible to apply different braking forces when the vehicle is sliding and when sliding in the second direction.

  The piston may separate the interior of the cylinder into a first chamber and a second chamber, and may have first to fourth check valves. The first check valve allows the hydraulic fluid to flow from the first chamber to the flow channel and prevents the hydraulic fluid from flowing from the flow channel to the first chamber, and the second check valve transfers from the flow channel to the second chamber. The third check valve allows the hydraulic fluid to flow from the second chamber to the flow path and allows the hydraulic fluid to flow from the second chamber to the flow path. The fourth check valve allows the hydraulic fluid to flow from the flow path to the first chamber and prevents the hydraulic fluid from flowing from the first chamber to the flow path. The fourth check valve has a rotational direction of the flow resistance member due to the flow of hydraulic fluid from the first check valve toward the second check valve, and the hydraulic fluid flows from the third check valve toward the fourth check valve. It may be arranged so as to be the same as the rotation direction of the flow resistance member.

  According to this aspect, the flow resistance member can be rotated in the same direction regardless of whether the piston slides in the first direction or the second direction. For this reason, it can avoid that the rotation direction of a flow resistance member reverses whenever a piston reciprocates, and can improve the durability of a flow resistance member.

  The piston has a relief valve interposed between a location upstream of the flow resistance member in the flow path and a liquid chamber behind the fluid flow when the working fluid flows in the flow path by sliding inside the cylinder. Also good. The relief valve may be opened when the hydraulic pressure of the hydraulic fluid at the upstream location becomes equal to or higher than a predetermined value, and the hydraulic fluid may flow out from the upstream location to the rear fluid chamber.

  According to this aspect, it is possible to prevent the damping force from being generated more than necessary due to the rotation of the flow resistance member, and to avoid the situation where the smooth flow of the working fluid between the liquid chambers is hindered. it can. Further, the flow resistance member can be prevented from rotating at a high speed, and the durability of the flow resistance member can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the shock absorber which can obtain suitable damping force can be provided, suppressing the enlargement of an apparatus and the increase in cost.

  Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a vehicle 10 on which a shock absorber control device 200 according to the first embodiment is mounted. The vehicle 10 is configured by assembling four wheels 14 to a vehicle body 12. The shock absorber control device 200 includes a wheel speed sensor 16, a shock absorber 18 </ b> A, a power generation motor 19, a variable resistor 20, a sprung G sensor 22, and an unsprung G, which are provided in the vehicle body 12 corresponding to each of the wheels 14. It has a sensor 24. The shock absorber control device 200 further includes a steering angle sensor 26 and an electronic control unit (hereinafter referred to as “ECU”) 30.

  The ECU 30 includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, and the like. Control. The wheel speed sensor 16 supplies a signal corresponding to the rotational speed of the wheel 14 to the ECU 30. The shock absorber 18A is interposed between a so-called unsprung suspension arm on which the wheels 14 are supported and a so-called support member on the spring provided with the vehicle cabin, and the impact applied to the vehicle is transmitted to the vehicle cabin. To suppress. A power generation motor 19 is attached to the shock absorber 18 </ b> A, and a variable resistance 20 is connected to the power generation motor 19. Each of the variable resistors 20 is connected to the ECU 30, and the ECU 30 controls the resistance value of the variable resistor 20. The generator motor 19 may be connected to a battery. Thereby, it is possible to regenerate the electric power generated by the generator motor 19.

  A sprung G sensor 22 is provided at a position corresponding to each of the wheels 14 in a vehicle casing (not shown) on the spring. A suspension member (not shown), which is an unsprung housing to which the suspension arm is connected, is provided with an unsprung G sensor 24 corresponding to each of the wheels 14. Each of the four sprung G sensors 22 detects the acceleration in the vertical direction in the vehicle casing in which the four sprung G sensors 22 are arranged. Each of the four unsprung G sensors 24 detects the acceleration in the vertical direction of the suspension member in which each of the four unsprung G sensors 24 is arranged. The steering angle sensor 26 detects the steering angle of the steering wheel 28. The detection results of the sprung G sensor 22, the unsprung G sensor 24, and the rudder angle sensor 26 are output to the ECU 30.

  FIG. 2 is a cross-sectional view of the shock absorber 18A according to the first embodiment. The shock absorber 18A includes a cylinder 40, a piston 42, a piston rod 44, and a mounting portion 46. The attachment portion 46 is attached below the cylinder 40. The attachment portion 46 is fixed to a suspension arm or the like. The cylinder 40 is formed in a cylindrical shape, and a cylinder chamber 40 a is formed inside the cylinder 40.

  A free piston 64 is disposed below the cylinder chamber 40 a, and an air chamber 40 d is provided in a region below the free piston 64. The air chamber 40d is filled with a gas such as air, and the free piston 64 slides up and down in the cylinder chamber 40a in accordance with the pressure difference between the upper cylinder chamber 40a and the air chamber 40d. .

  The cylinder chamber 40a above the free piston 64 is filled with oil as hydraulic fluid. The piston 42 is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the cylinder 40. The piston 42 is inserted into the cylinder chamber 40a, and divides the cylinder chamber 40a into an upper first chamber 40b and a lower second chamber 40c. The lower end of an elongated cylindrical piston rod 44 is coaxially fixed to the upper end of the piston 42. An insertion hole is provided above the cylinder 40, and the piston rod 44 is inserted into the insertion hole so as to protrude above the cylinder 40. Thus, as the piston 42 slides in the cylinder chamber 40a, the protrusion amount of the piston rod 44 from the cylinder 40 changes, and the entire shock absorber 18A expands and contracts.

  The piston 42 is formed with a flow path 42a through which hydraulic fluid flows. When the piston 42 slides upward and downward in the cylinder chamber 40a, the hydraulic fluid in the sliding front liquid chamber flows into the flow path 42a and flows out into the rear liquid chamber. Specifically, the piston 42 slides downward in the cylinder chamber 40a while flowing the hydraulic fluid in the second chamber 40c into the flow path 42a and outflowing into the first chamber 40b. Conversely, the piston 42 slides upward in the cylinder chamber 40a while flowing the hydraulic fluid in the first chamber 40b into the flow path 42a and outflowing into the second chamber 40c. The flow path 42 a has an upper surface and a lower surface that are planes perpendicular to the axial direction of the piston 42, and is formed so as to spread in the direction perpendicular to the axial direction of the piston 42 inside the piston 42.

  A first gear 50 and a second gear 52 are disposed in the flow path 42a. The first gear 50 and the second gear 52 are formed in the same shape, and the gear specifications such as the number of teeth are the same. The first gear 50 and the second gear 52 are arranged so that their axial directions are parallel to the axial direction of the piston 42 while meshing with each other. The first gear 50 is fixed to the first shaft 54, and the second gear 52 is fixed to the second shaft 56. A first shaft 54 is attached to the piston 42 via a bearing, and the first gear 50 is rotatably supported by the piston 42. The second shaft 56 is attached to the piston 42 via a bearing, and the second gear 52 is rotatably supported by the piston 42.

  Here, the internal configuration of the flow path 42a will be described in detail with reference to FIG. 3 is a cross-sectional view taken along the line PP in FIG. The flow path 42a includes a portion in which two large arcs formed so as to be slightly larger than the meshing first gear 50 and the second gear 52 are coupled, and a straight line extending in a direction away from the arc coupling portion. It consists of two parts. In addition, the piston 42 includes a first communication passage 42b that allows one linear portion of the flow path 42a to communicate with the first chamber 40b, and a second linear portion of the flow path 42a and the second chamber 40c. A second communication path 42c for communication is formed.

  The first gear 50 and the second gear 52 are arranged in mesh with each other in two large arc-shaped portions of the flow path 42a. For example, when the piston 42 slides upward, the hydraulic fluid flows into the flow path 42a from the first communication path 42b, and the flow path 42a on the first communication path 42b side is bordered by the first gear 50 and the second gear 52. The pressure is higher than the flow path 42a on the second communication path 42c side. Since the first gear 50 and the second gear 52 are meshed with each other, the differential gear causes the first gear 50 to rotate clockwise and the second gear 52 to rotate counterclockwise as shown in FIG. When the piston 42 slides downward, on the contrary, the first gear 50 rotates counterclockwise and the second gear 52 rotates clockwise. At this time, the first gear 50 and the second gear 52 generate a flow resistance between the flowing hydraulic fluid. Accordingly, the first gear 50 and the second gear 52 function as flow resistance members. The first gear 50 and the second gear 52 rotate at a rotation speed corresponding to the flow speed of the hydraulic fluid in the flow path 42a.

  Returning to FIG. A gear 58 is fixed to the upper end of the first shaft 54. A rotary shaft 62 is inserted into the piston rod 44, and a gear 60 is fixed to the lower end of the rotary shaft 62. The gear 58 and the gear 60 are meshed. As described above, when the first gear 50 is rotated, the rotating shaft 62 is rotationally driven via the gear 58 and the gear 60.

A generator motor 19 is attached to the upper end of the piston rod 44. The rotation shaft 62 in the piston rod 44 is coupled to the internal mechanism of the power generation motor 19, and the power generation motor 19 generates power according to the rotation speed of the rotation shaft 62. Since the power generation motor 19 is a known technique, a description of the power generation process of the power generation motor 19 is omitted. A variable resistor 20 is connected to the generator motor 19, and the current generated by the generator motor 19 is supplied to the variable resistor 20. When the electric power generated by the generator motor 19 is consumed by the variable resistor 20 in this way, a braking force is applied to the rotating first gear 50 through the rotating shaft 62 and the like. At this time, a braking force is similarly applied to the second gear 52 that meshes with the first gear 50. Therefore, the generator motor 19 and the variable resistor 20 function as a braking unit that applies a braking force to the first gear 50 and the second gear 52. The generator motor applies a braking force according to the rotation speed of the first gear 50 to the first gear 50. Here, the torque applied to the first gear 50 and the second gear 52 is:
T = q × ΔP / 2π
T: Torque [N / m]
q: Gear pump discharge amount [cc / rev]
ΔP: differential pressure [MPa] between the first communication path 42b side and the second communication path 42c side in the flow path 42a
It is represented by This is the first equation.

Further, the theoretical formula of the torque of the generator motor 19 is
T = Ke × Kt × N / R
Ke: Back electromotive force constant [V · sec / rad]
Kt: Torque constant [N · m / A]
N: rotational speed of first gear 50 [rad / sec]
R: resistance value of variable resistor 20 [Ω]
It is represented by This is the second equation.

From the first and second equations, ΔP is
ΔP = 2π × Ke × Kt × N / (R × q)
It is represented by This is the third equation. As represented by the third equation, ΔP can be changed by changing the resistance value of the variable resistor 20.

  The ECU 30 changes the braking force applied to the rotating first gear 50 and the second gear 52 by changing the resistance value of the variable resistor 20 and controls the damping force applied to the piston 42. Therefore, the ECU 30 functions as damping force control means.

  The ECU 30 uses the detection results of the wheel speed sensor 16, the sprung G sensor 22, the unsprung G sensor 24, and the rudder angle sensor 26, for example, based on the equation of motion or transfer function in the skyhook system, and so on. Determine the target damping force that should be generated. The ECU 30 calculates a target resistance value of the variable resistor 20 for generating the target damping force, and changes the variable resistor 20 to the calculated target resistance value. Since the technique for determining the target damping force to be generated by the shock absorber based on the equation of motion, transfer function, etc. in the skyhook system is well known, the description thereof is omitted. Of course, the method for determining the target damping force is not limited to the one based on the equation of motion or transfer function in the skyhook system.

  In the first embodiment, the ROM of the ECU 30 includes the speed of the vehicle 10, the steering angle of the steering wheel 28, and the target damping force when the shock absorber 18A is expanded and contracted, which is calculated in advance from the skyhook system. A map associated with each other is stored. The target damping force associated with the map is individually provided at the time of expansion and contraction. Further, the target damping force associated with the map is provided stepwise according to the difference between the vertical acceleration on the spring and the vertical acceleration on the spring, that is, the acceleration of the piston 42 relative to the cylinder 40. Yes. The ECU 30 calculates the speed of the vehicle 10 using the detection result of the wheel speed sensor 16. Further, the ECU 30 determines whether the shock absorber 18A is extended or contracted by using the detection results of the sprung G sensor 22 and the unsprung G sensor 24. Thus, the ECU 30 performs shock according to the calculated speed of the vehicle 10, the determination result of whether the vehicle 10 is expanding or contracting, the steering angle of the steering wheel 28, and the detection results of the sprung G sensor 22 and the unsprung G sensor 24. The target damping force of the absorber 18A is set using the above map. A stroke sensor for detecting expansion / contraction of the shock absorber 18A may be provided, and the ECU 30 may determine whether the shock absorber 18A is extended or contracted using the detection result of the stroke sensor. Good.

  At this time, the ECU 30 may cause the shock absorber 18A to generate a high damping force as the vehicle speed increases. Further, when the vehicle turns, a large compressive force is applied to the shock absorber corresponding to the outer wheel far from the turning center. Therefore, when the ECU 30 determines that the vehicle 10 is turning in either the left or right direction based on the detection result of the rudder angle sensor 26, the ECU 30 applies the shock absorber 18A corresponding to the wheel 14 on the outside of the turn from the time of straight ahead. Alternatively, a high damping force may be generated. The ECU 30 may generate a higher damping force on the shock absorber 18A corresponding to the wheel 14 on the outer side of the turn as the rudder angle detected by the rudder angle sensor 26 is larger, and as the vehicle speed at the time of turning increases. A high damping force may be generated in the shock absorber 18A corresponding to the wheel 14 on the outside of the turn.

  FIG. 4 is a diagram showing the relationship between the sliding speed V of the piston 42 and the damping force F applied to the piston 42 when the shock absorber 18A according to the first embodiment is used. As shown by a solid line in FIG. 4, when the shock absorber 18A is used, the relationship between the sliding speed V and the damping force F is a linear relationship. Therefore, a higher damping force F is applied to the piston 42 in a region where the sliding speed V is low as compared with a shock absorber as shown by a broken line in FIG. 4 that does not use the first gear 50, the generator motor 19, and the variable resistor 20. Is possible.

(Second Embodiment)
FIG. 5 is a cross-sectional view of a shock absorber 18B according to the second embodiment. The configuration of the shock absorber control device 200 according to the second embodiment is the same as that of the first embodiment except that a shock absorber 18B is mounted instead of the shock absorber 18A. Further, in the shock absorber 18B, the same parts as those in the shock absorber 18A according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The shock absorber 18B has a piston 80. The piston 80 is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the cylinder 40. The piston 80 is inserted into the cylinder chamber 40a and separates the cylinder chamber 40a into a first chamber 40b and a second chamber 40c. The lower end of the piston rod 44 is coaxially fixed to the upper end of the piston 80.

  The piston 80 is formed with a first flow path 80a and a second flow path 80b through which hydraulic fluid flows. Each of the first flow path 80a and the second flow path 80b has an upper surface and a lower surface that are planes perpendicular to the axial direction of the piston 80, and extends in the direction perpendicular to the axial direction of the piston 80 inside the piston 80. Is formed. The shapes of the first flow path 80a and the second flow path 80b viewed from the axial direction are the same as the shape of the flow path 42a in the first embodiment.

  A first gear 50 and a second gear 52 are disposed in the first flow path 80a. A third gear 86 and a fourth gear 88 are disposed in the second flow path 80b. The first gear 50 and the second gear 52 are arranged in the first flow path 80 a so that their axial directions are parallel to the axial direction of the piston 80 while meshing with each other. Further, the third gear 86 and the fourth gear 88 are arranged in the second flow path 80 b so that their axial directions are parallel to the axial direction of the piston 80 while meshing with each other. The first gear 50 and the third gear 86 are fixed to the first shaft 82, and the second gear 52 and the fourth gear 88 are fixed to the second shaft 84. A first shaft 82 is attached to the piston 80 via a bearing, and both the first gear 50 and the third gear 86 are rotatably supported by the piston 80. The second shaft 84 is attached to the piston 80 via a bearing, and both the second gear 52 and the fourth gear 88 are supported by the piston 80 so as to be rotatable.

  6 is a cross-sectional view taken along the line QQ in FIG. In FIG. 6, illustration of the piston rod 44 and the rotating shaft 62 is omitted. Inside the piston 80, the first gear 50, the second gear 52, the third gear 86, and the fourth gear 88 are sandwiched between the first communication passage 80c that communicates with the first chamber 40b and the second chamber 40c. A second communication path 80d that communicates is formed. Each of the first flow path 80a and the second flow path 80b is connected to the first communication path 80c and the second communication path 80d.

  The piston 80 is provided with a first check valve 90 and a second check valve 92. Since a known check valve is used for the first check valve 90 and the second check valve 92, a description of the configuration is omitted. The first check valve 90 allows the hydraulic fluid to flow from the second flow path 80b to the first communication path 80c, and prevents the hydraulic fluid from flowing from the first communication path 80c to the second flow path 80b. The second check valve 92 allows the hydraulic fluid to flow from the second communication path 80d to the second flow path 80b, and prevents the hydraulic fluid from flowing from the second flow path 80b to the second communication path 80d.

  Thereby, when the shock absorber 18B extends, the hydraulic fluid flows only from the first chamber 40b to the second chamber 40c through the first flow path 80a as shown by the arrow F1. However, when the shock absorber 18B contracts, the hydraulic fluid flows from the second chamber 40c to the first chamber 40b through both the first flow path 80a and the second flow path 80b as indicated by the arrow F2. . For this reason, when the shock absorber 18B contracts, the damping force applied to the piston 80 becomes lower than when the shock absorber 18B expands.

  FIG. 7 is a view showing the relationship between the sliding speed V of the piston 42 and the damping force F applied to the piston 42 when the shock absorber 18B according to the second embodiment is used. In FIG. 7, the sliding speed V of the piston 80 represents the sliding direction of the piston 80 when the shock absorber 18B extends, that is, the speed at which the piston 80 slides upward.

  As shown by the solid line in FIG. 7, when the shock absorber 18B is used, the first implementation is performed while maintaining the linear relationship between the sliding speed V and the damping force F in the region where the shock absorber 18B contracts. The damping force F with respect to the sliding speed V can be set lower than the broken line in FIG. 7 showing the case where the shock absorber 18A according to the embodiment is used. There is a case where a large impact is applied to the wheel 14 in the upward direction when riding on a convex portion or the like. On the other hand, even if the wheel 14 passes through the recess, a large impact is not usually given downward. For this reason, the shock absorber may be required to have a lower damping force F when contracting than when expanding even at the same sliding speed V. According to the shock absorber 18B, it is possible to set a different damping force with a simple configuration when extending and contracting.

(Third embodiment)
FIG. 8 is a diagram illustrating a configuration of the variable resistance unit 100 according to the third embodiment. The same parts as those of the shock absorber 18A according to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  In the third embodiment, the variable resistance unit 100 is connected to the generator motor 19. The variable resistance unit 100 includes a first variable resistance 102, a second variable resistance 104, a first diode 106, and a second diode 108.

  In the shock absorber 18A, the rotation directions of the first gear 50 and the second gear 52 are opposite when the piston 42 slides upward and when the piston 42 slides downward. Therefore, the direction in which the current generated by the generator motor 19 flows to the variable resistance unit 100 is reversed when the piston 42 slides upward and when the piston 42 slides downward. The first diode 106 prevents the first variable resistor 102 from supplying the current generated by the generator motor 19 when the piston 42 slides downward. The second diode 108 prevents the current generated by the generator motor 19 from being supplied to the second variable resistor 104 when the piston 42 slides upward. As a result, when the shock absorber 18 </ b> A extends, current is supplied only to the first variable resistor 102 without supplying current to the second variable resistor 104. Conversely, when the shock absorber 18A contracts, current is supplied only to the second variable resistor 104 without supplying current to the first variable resistor 102.

  FIG. 9 is a diagram illustrating the relationship between the sliding speed V of the piston 42 and the damping force F applied to the piston 42 when the variable resistance unit 100 according to the third embodiment is used. In FIG. 9, the sliding speed V of the piston 80 represents the sliding direction of the piston 80 when the shock absorber 18B extends, that is, the speed at which the piston 80 slides upward.

  By configuring the variable resistance unit 100 as described above, the first variable resistance 102 and the second variable resistance 104 are set to different resistance values, so that the shock absorber 18 </ b> A is expanded and contracted. The damping force F can be easily generated. Therefore, for example, by setting the resistance value of the first variable resistor 102 to be lower than the resistance value of the second variable resistor 104, as shown by the solid line in FIG. While maintaining a linear relationship with the damping force F, the damping force F with respect to the sliding speed V can be easily compared with the broken line in FIG. 9 showing the case where the shock absorber 18A according to the first embodiment is used. Can be set low.

(Fourth embodiment)
FIG. 10 is a cross-sectional view of a shock absorber 18C according to the fourth embodiment. The configuration of the shock absorber control device 200 according to the second embodiment is the same as that of the first embodiment except that a shock absorber 18C is mounted instead of the shock absorber 18A. In the shock absorber 18C, the same parts as those of the shock absorber 18A according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The shock absorber 18C has a piston 120. FIG. 10 shows the periphery of the piston 120, and the other configuration of the shock absorber 18C not shown in FIG. 10 is the same as that of the shock absorber 18A. As in the first embodiment, the shock absorber 18C has a first gear 50 and a second gear 52 that mesh with each other. FIG. 10 shows a cross section of the piston 120 when the second gear 52 side is seen from the meshing portion.

  The piston 120 is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the cylinder 40. The piston 120 is inserted into the cylinder chamber 40a and separates the cylinder chamber 40a into a first chamber 40b and a second chamber 40c. The lower end of the piston rod 44 is fixed coaxially to the upper end of the piston 120. In FIG. 10, illustration of the piston rod 44 and the rotating shaft 62 is omitted.

  The piston 120 is formed with a flow path 120a through which hydraulic fluid flows. The shape of the flow path 120a is the same as that of the flow path 42a in the first embodiment. Moreover, the support mode of the 1st gear 50 and the 2nd gear 52 in the flow path 120a is the same as that of 1st Embodiment. The piston 120 is formed with a first communication path 120b that allows the first chamber 40b and the flow path 120a to communicate with each other, and a third communication path 120d that allows the second chamber 40c and the flow path 120a to communicate with each other. It is formed coaxially with the communication path 120b. Further, the piston 120 is formed with a fourth communication path 120e that allows the flow path 120a and the first chamber 40b to communicate with each other, and the second communication path 120c that allows the second chamber 40c and the flow path 120a to communicate with each other. It is formed coaxially with the four communication passages 120e. The first communication path 120b and the third communication path 120d, and the second communication path 120c and the fourth communication path 120e are arranged at positions sandwiching the first gear 50 and the second gear 52.

  A first check valve 122 is provided in the first communication path 120b, and a second check valve 124 is provided in the second communication path 120c. In addition, a third check valve 126 is provided in the third communication path 120d, and a fourth check valve 128 is provided in the fourth communication path 120e. Since known check valves are used for the first to fourth check valves 122, 124, 126, and 128, description of the configuration is omitted.

  The first check valve 122 allows the hydraulic fluid to flow from the first chamber 40b to the flow channel 120a, and prevents the hydraulic fluid from flowing from the flow channel 120a to the first chamber 40b. The second check valve 124 allows the hydraulic fluid to flow from the flow path 120a to the second chamber 40c, and prevents the hydraulic fluid from flowing from the second chamber 40c to the flow path 120a. The third check valve 126 allows the hydraulic fluid to flow from the second chamber 40c to the flow channel 120a, and prevents the hydraulic fluid from flowing from the flow channel 120a to the second chamber 40c. The fourth check valve 128 allows the hydraulic fluid to flow from the flow path 120a to the first chamber 40b, and prevents the hydraulic fluid from flowing from the first chamber 40b to the flow path 120a.

  As a result, when the piston 120 slides upward, as shown by the arrow F3, the hydraulic fluid in the first chamber 40b passes through the first communication path 120b and flows into the flow path 120a, and the second communication path 120c. Flows out into the second chamber 40c. Therefore, the hydraulic fluid flows around the first gear 50 and the second gear 52 in the left direction in FIG. Conversely, when the piston 120 slides downward, as shown by the arrow F4, the hydraulic fluid in the second chamber 40c passes through the third communication path 120d and flows into the flow path 120a, and passes through the fourth communication path 120e. It passes through and flows out into the first chamber 40b. For this reason, even when the piston 120 slides downward, the periphery of the first gear 50 and the second gear 52 moves toward the left in FIG. 10, which is the same direction as when the piston 120 slides upward. The hydraulic fluid flows. Accordingly, the first gear 50 and the second gear 52 rotate in the same direction regardless of whether the piston 120 slides upward or downward. Accordingly, it is possible to prevent the first gear 50 and the second gear 52 from rotating in reverse each time the piston 120 reciprocates, and the durability of the first gear 50 and the second gear 52 can be improved.

(Fifth embodiment)
FIG. 11 is a cross-sectional view of a shock absorber 18D according to the fifth embodiment. The configuration of the shock absorber control device 200 according to the fifth embodiment is the same as that of the first embodiment except that a shock absorber 18D is mounted instead of the shock absorber 18A. Further, in the shock absorber 18D, the same parts as those in the shock absorber 18A according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The shock absorber 18D has a piston 140. FIG. 11 shows the periphery of the piston 140, and other configurations of the shock absorber 18D not shown in FIG. 11 are the same as those of the shock absorber 18A.

  The piston 140 is formed with a flow path 140a through which hydraulic fluid flows. The shape of the flow path 140a is the same as that of the flow path 42a in the first embodiment. Similarly to the first embodiment, the shock absorber 18D includes a first gear 50 and a second gear 52 that mesh with each other. FIG. 11 shows a cross section of the piston 120 when the second gear 52 side is viewed from the meshing position. The support mode of the first gear 50 and the second gear 52 in the flow path 140a is the same as that of the first embodiment.

  Piston 140 is integrally coupled to piston rod 158. Inside the piston rod 158, a rotating shaft 162 is coaxially disposed so as to be rotatable. The first gear 50 is connected to the rotating shaft 162 via a gear (not shown), and the rotating shaft 162 rotates together with the first gear 50. The rotating shaft 162 is connected to the generator motor 19. Accordingly, when the first gear 50 rotates, power is generated by the generator motor 19, and current is supplied to the variable resistor 20. Thus, also in the fifth embodiment, braking force is applied to the first gear 50 and the second gear 52 by the generator motor 19 and the variable resistor 20 during rotation.

  The piston 120 is formed with a first communication path 140b that allows the second chamber 40c and the flow path 140a to communicate with each other. The piston 120 is formed with a second communication path 140c that allows the first chamber 40b and the flow path 140a to communicate with each other on the opposite side of the first communication path 140b with the first gear 50 and the second gear 52 interposed therebetween. Yes.

  Further, the piston 140 is formed with a third communication path 140d that allows the first communication path 140b and the first chamber 40b to communicate with each other, and a fourth communication path that allows the second communication path 140c and the second chamber 40c to communicate with each other. A communication path 140e is formed. A first relief valve 142 is provided in the third communication path 140d. The first relief valve 142 prevents communication from the first chamber 40b to the first communication path 140b, and opens when the hydraulic pressure of the hydraulic fluid in the first communication path 140b exceeds a predetermined value. The communication from the communication path 140b to the first chamber 40b is allowed. A second relief valve 144 is provided in the fourth communication path 140e. The second relief valve 144 prevents communication from the second chamber 40c to the second communication path 140c, and opens when the hydraulic pressure of the hydraulic fluid in the second communication path 140c exceeds a predetermined value. The communication from the communication path 140c to the second chamber 40c is allowed. The first relief valve 142 and the second relief valve 144 are each configured by a spring, a valve seat, and a ball pressed against the valve seat by the biasing force of the spring.

  A first main valve unit 146 is provided above the piston 140. The first main valve unit 146 includes a first valve seat member 148 and a first main valve 150. The first valve seat member 148 is fixed above the piston 140, and the first main valve 150 is further mounted thereon. The first main valve 150 is configured by a leaf valve. The first main valve unit 146 allows communication from the third communication passage 140d to the first chamber 40b by deforming the first main valve 150 so as to be separated from the upper surface of the first valve seat member 148. The valve 150 abuts on the upper surface of the first valve seat member 148, thereby preventing communication from the first chamber 40b to the third communication passage 140d.

  A second main valve unit 152 is provided below the piston 140. The second main valve unit 152 includes a second valve seat member 154 and a second main valve 156. The second valve seat member 154 is fixed below the piston 140, and the second main valve 156 is further attached below it. The second main valve unit 152 allows the second main valve 156 to be separated from the lower surface of the second valve seat member 154, thereby allowing communication from the fourth communication path 140e to the second chamber 40c. The valve 156 contacts the lower surface of the second valve seat member 154, thereby preventing communication from the second chamber 40c to the fourth communication path 140e.

  FIG. 12A is a diagram illustrating an aspect of the flow path of the hydraulic fluid when the piston 140 slides downward. Even when the piston 140 moves downward, the first relief valve 142 remains closed if the hydraulic fluid pressure in the first communication passage 140b is smaller than a predetermined value. Therefore, the hydraulic fluid in the second chamber 40c does not flow from the first communication path 140b into the third communication path 140d but flows into the flow path 140a and flows out to the first chamber 40b through the second communication path 140c.

  FIG. 12B is a diagram showing another aspect of the flow path of the hydraulic fluid when the piston 140 slides downward. When the hydraulic pressure of the hydraulic fluid in the first communication passage 140b becomes larger than a predetermined value due to the downward movement of the piston 140, the first relief valve 142 opens and the first communication passage 140b and the first chamber 40b are connected. Communicate. For this reason, part of the hydraulic fluid that has flowed into the first communication path 140b passes through the third communication path 140d and the first main valve unit 146 and flows out to the first chamber 40b.

  FIG. 13A is a diagram illustrating an aspect of the flow path of the hydraulic fluid when the piston 140 slides upward. Even when the piston 140 moves upward, the second relief valve 144 remains closed if the hydraulic fluid pressure in the second communication passage 140c is smaller than a predetermined value. Therefore, the hydraulic fluid in the first chamber 40b does not flow from the second communication path 140c to the fourth communication path 140e but flows into the flow path 140a, and flows out to the second chamber 40c through the first communication path 140b. .

  FIG. 13B is a diagram showing another aspect of the flow path of the hydraulic fluid when the piston 140 slides upward. When the hydraulic pressure of the hydraulic fluid in the second communication passage 140c becomes larger than a predetermined value due to sliding of the piston 140 upward, the second relief valve 144 is opened, and the second communication passage 140c, the second chamber 40c, Communicate. For this reason, part of the hydraulic fluid that has flowed into the second communication path 140c passes through the fourth communication path 140e and the second main valve unit 152 and flows out into the second chamber 40c.

  FIG. 14 shows the difference between the flow rate Q of the working fluid flowing between the first chamber 40b and the second chamber 40c as the piston 140 slides, and the first communication passage 140b and the second communication passage 140c. It is a figure which shows the relationship with the pressure (DELTA) P. In FIG. 14, the amount of hydraulic fluid flowing from the second chamber 40c to the first chamber 40b is positive, and the value obtained by subtracting the hydraulic pressure of the second communication passage 140c from the hydraulic pressure of the first communication passage 140b is ΔP. It is said.

  As the differential pressure between the hydraulic pressure in the first communication path 140b and the hydraulic pressure in the second communication path 140c increases, the rotation speeds of the first gear 50 and the second gear 52 increase, and the generator motor 19 and the variable resistance 20 At the same time, the braking force given by Therefore, in a state where the first relief valve 142 and the second relief valve 144 remain closed, as shown by a broken line in FIG. 14, even if the differential pressure ΔP increases, a large flow rate Q is increased with the first chamber 40b. It becomes difficult to flow between the second chamber 40c. In this way, when the hydraulic pressure of the hydraulic fluid at the upstream location of the flow path 140a exceeds a predetermined value, the relief valve interposed between the upstream location and the rear fluid chamber is opened. Thereby, the differential pressure | voltage of the 1st communicating path 140b and the 2nd communicating path 140c can be suppressed. For this reason, as shown in FIG. 14, the flow rate Q can be smoothly increased in accordance with the increase in the differential pressure ΔP.

  Further, as the rotational speeds of the first gear 50 and the second gear 52 are increased, loads applied to the first gear 50 and the second gear 52 are also increased. By providing the first relief valve 142 and the second relief valve 144 in this manner, the load applied to the first gear 50 and the second gear 52 can be reduced, and the durability of the first gear 50 and the second gear 52 can be reduced. It becomes possible to improve the property.

  The present invention is not limited to the above-described embodiment, and an appropriate combination of the elements of this embodiment is also effective as an embodiment of the present invention. Various modifications such as various design changes can be added to the present embodiment based on the knowledge of those skilled in the art, and the embodiments with such modifications can be included in the scope of the present invention.

1 is an overall configuration diagram of a vehicle equipped with a shock absorber control device according to a first embodiment. It is sectional drawing of the shock absorber which concerns on 1st Embodiment. It is PP sectional drawing in FIG. It is a figure which shows the relationship between the sliding speed V of the piston when using the shock absorber which concerns on 1st Embodiment, and the damping force F given to a piston. It is sectional drawing of the shock absorber which concerns on 2nd Embodiment. It is QQ sectional drawing of FIG. It is a figure which shows the relationship between the sliding speed V of the piston when using the shock absorber which concerns on 2nd Embodiment, and the damping force F given to a piston. It is a figure which shows the structure of the variable resistance unit which concerns on 3rd Embodiment. It is a figure which shows the relationship between the sliding speed V of a piston when using the variable resistance unit which concerns on 3rd Embodiment, and the damping force F given to a piston. It is sectional drawing of the shock absorber which concerns on 4th Embodiment. It is sectional drawing of the shock absorber which concerns on 5th Embodiment. (A) is a figure which shows the one aspect | mode of the flow path | route of a hydraulic fluid when a piston slides below, (b) is another figure of the flow path | route of a hydraulic fluid when a piston slides below. It is a figure which shows an aspect. (A) is a figure which shows the one aspect | mode of the flow path | route of a hydraulic fluid when a piston slides upwards, (b) is another figure of the flow path | route of a hydraulic fluid when a piston slides upwards It is a figure which shows an aspect. It is a figure which shows the relationship between the flow volume Q of the hydraulic fluid which flows between a 1st chamber and a 2nd chamber when a piston slides, and the differential pressure (DELTA) P between a 1st communicating path and a 2nd communicating path. is there.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Vehicle, 12 Vehicle body, 14 Wheel, 16 Wheel speed sensor, 18A-18D Shock absorber, 19 Electric motor, 20 Variable resistance, 22 On-spring G sensor, 24 Unsprung G sensor, 26 Steering angle sensor, 30 ECU, 40 Cylinder, 40a cylinder chamber, 40b first chamber, 40c second chamber, 42 piston, 42a flow path, 42b first communication passage, 42c second communication passage, 50 first gear, 52 second gear, 62 rotating shaft, 200 Shock absorber control device.

Claims (7)

In the shock absorber control device that controls the damping force when the shock absorber expands and contracts,
A flow path through which the working fluid flows, a piston that slides inside the cylinder while flowing the working fluid in the liquid chamber in the front in the sliding direction into the flow path and out to the liquid chamber in the rear in the sliding direction;
A flow resistance member that is provided in the flow path so as to rotate by the flow of the hydraulic fluid in the flow path, and generates a flow resistance between the hydraulic fluid;
Braking means for applying a braking force to the rotating flow resistance member;
A damping force control means for controlling a damping force applied to the piston by changing a braking force applied to the flow resistance member;
A shock absorber control device comprising: The braking means includes a power generation means for generating electric power using the rotational motion of the flow resistance member, and a variable resistor connected to the power generation means, and the generated current is supplied to the variable resistance. Giving a braking force to the flow resistance member;
The said damping force control means controls the damping force given to the said piston by changing the braking force given to the said flow resistance member by changing the resistance value of the said variable resistance. The shock absorber control device described.   The shock absorber control device according to claim 2, wherein the power generation means is disposed outside the cylinder. The flow resistance member rotates in a third direction due to the flow of hydraulic fluid in the flow path when the piston slides in the first direction in the cylinder, and the piston moves in the cylinder in the first direction. Rotating in the fourth direction opposite to the third direction by the flow of the working fluid in the flow path when sliding in the second direction opposite to the one direction,
The variable resistor includes a first variable resistor and a second variable resistor connected to the power generation means, and a current generated by using the rotational movement of the flow resistance member in the fourth direction to the first variable resistor. A first diode for blocking supply; and a second diode for blocking supply of current generated by using the rotational movement of the flow resistance member in the third direction to the second variable resistor,
4. The shock absorber control device according to claim 2, wherein the damping force control means changes a resistance value of the first variable resistor and a resistance value of the second variable resistor. The piston has a first flow path and a second flow path through which hydraulic fluid flows, and a flow of the hydraulic fluid into the second flow path when the piston slides in the first direction inside the cylinder. And a check valve that prevents the flow of hydraulic fluid to the second flow path when the piston slides in the second direction opposite to the first direction inside the cylinder. ,
The flow resistance member includes a first flow resistance member and a second flow resistance member that rotate together, and the first flow resistance member rotates in response to the flow of hydraulic fluid in the first flow path. Provided in the path, the second flow resistance member is provided in the second flow path so as to rotate by the flow of the working fluid in the second flow path,
The shock absorber control device according to any one of claims 1 to 4, wherein the braking means applies a braking force to the first flow resistance member and the second flow resistance member. The piston separates the inside of the cylinder into a first chamber and a second chamber, and has first to fourth check valves,
The first check valve allows the hydraulic fluid to flow from the first chamber to the flow path and prevents the hydraulic fluid from flowing from the flow path to the first chamber;
The second check valve allows the hydraulic fluid to flow from the flow path to the second chamber and prevents the hydraulic fluid from flowing from the second chamber to the flow path;
The third check valve allows the hydraulic fluid to flow from the second chamber to the flow path and prevents the hydraulic fluid from flowing from the flow path to the second chamber;
The fourth check valve allows the hydraulic fluid to flow from the flow path to the first chamber and prevents the hydraulic fluid from flowing from the first chamber to the flow path;
In the first to fourth check valves, the rotational direction of the flow resistance member due to the flow of the hydraulic fluid from the first check valve toward the second check valve is determined from the third check valve to the fourth check valve. The shock absorber control device according to any one of claims 1 to 3, wherein the shock absorber control device is arranged so as to be the same as a rotation direction of the flow resistance member caused by the flow of the hydraulic fluid toward the valve. The piston is a relief that is interposed between a location upstream of the flow resistance member in the flow path and a rear liquid chamber when the working fluid flows in the flow path by sliding inside the cylinder. Have a valve,
The relief valve is opened when the hydraulic pressure of the hydraulic fluid at the upstream location becomes equal to or higher than a predetermined value, and allows the hydraulic fluid to flow out from the upstream location to the rear fluid chamber. Item 7. The shock absorber control device according to any one of Items 1 to 6.

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