JPH023514A - Damping force adjusting type hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To prevent the generation of a nose dividing phenomenon at quick service time by switching the damping force of a hydraulic shock absorber to a high damping force side preferentially despite the switching position of a changeover switch at the time when the operation of a brake is detected. CONSTITUTION:When a voltage is impressed with the contact 42A for soft or the contact 42B for normal of a changeover switch 42 being respectively opened, plural output circuits 43, 44, etc. outputting a signals '1' respectively are provided on a changeover switch circuit 36. On a brake operation detecting part 45 the brake pressure sensor 46 detecting the liquid pressure of a brake liquid and the output circuit 47, etc. outputting signals '1' at the time when the liquid pressure of the brake liquid becomes more than the specified are provided. On a control part 52, moreover, the plural OR circuits 54-56 connected to each of the output circuit 43, 44, 47 gradually in order and the output circuit 57 connected to those are provided. At the operation time of a brake the damping force is preferentially controlled to a 'High' side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention is a hydraulic shock absorber installed in a vehicle etc. to buffer its vibrations in multiple stages, which particularly improves the maneuverability and stability of the vehicle. The present invention also relates to a damping force adjustable hydraulic shock absorber that can ensure a comfortable ride. [Prior art 1] A shock absorber installed on a vehicle has a damping force characteristic that changes depending on the driving conditions of the vehicle, such as when driving on a highway, on a general road, on a gravel road, or on an uneven road. It is preferable not only from the viewpoint of ride comfort but also from the viewpoint of steering stability. From this point of view, the so-called damping force adjustable hydraulic shock absorber is equipped with a variable damping force generating mechanism that can change the damping force as appropriate depending on driving conditions, etc. is used. Here, in the conventional variable damping force generation mechanism, a control rod is provided through the piston rod, and an actuator such as a solenoid or a motor is connected to the outer end of the cylinder of the control rod.
A shutter that is rotated by the control rod is attached to the inner end of the cylinder, and by changing the passage area of the orifice, the damping force can be switched to soft, which is a low damping force, or hard, which is a high damping force. It has become. By the way, as mentioned above, the damping force adjustable hydraulic shock absorber according to the prior art has a structure that can be manually switched between soft and hard. Soft with low damping force,
We proposed a damping force adjustable hydraulic shock absorber that has three levels: normal damping force and hard damping force. In the above-mentioned three-stage hydraulic shock absorber, the changeover switch for adjusting the damping force of the damping force generation mechanism includes a manual changeover switch and an automatic changeover switch, both of which operate selectively. There is. The manual changeover switch can be switched between soft, normal, and hard depending on the driver's will. On the other hand, with an automatic changeover switch, the damping force is usually set to either soft or normal depending on the driver's will, and the damping force is normally set to either soft or normal depending on the driver's will. The control device operates to automatically switch from a soft or normal state to a hard state. As a result, even if the damping force is set to soft or normal, when it is determined that it is necessary to switch the damping force to hard due to, for example, taking a sharp curve at high speed, the damping force can be automatically switched to hard. [Problems to be Solved by the Invention] However, in the damping force adjustable hydraulic shock absorber according to the prior art configured as described above, the driver cannot change the automatic changeover switch from soft to normal or from normal to soft. As a result, if the actuator receives an impact force due to sudden braking while the damping force generation mechanism is rotating, the actuator that activates the damping force generation mechanism should give priority to the one that is switched by the driver. There was an unresolved problem in that it was not possible to determine whether priority should be given to switching to hard or hard based on commands from the control device, resulting in a loss of maneuverability and stability. In particular, if a hard command is output while switching from normal to soft, it may become unclear whether the actuator should operate in the forward or reverse direction, or the previous manual switching operation may be completed. Later, you will either need to switch to hardware. However, even though it is necessary to switch to a hard damping force as quickly as possible when braking suddenly, the slow operation described above has the disadvantage that it cannot cope with the rapid switching of the damping force. The present invention has been made in view of the drawbacks of the prior art, and when the driver operates the brake while switching the changeover switch to a state other than high, priority is given to the hard brake, thereby improving the maneuverability and stability of the vehicle. It is an object of the present invention to provide a damping force adjustable hydraulic shock absorber with improved performance. Means for Solving Problems] In order to achieve the above object, the configuration adopted by the present invention is as follows:
A damping force adjustable hydraulic shock absorber capable of adjusting the damping force in at least two levels between high and low; and a damping force adjustable hydraulic shock absorber capable of adjusting the damping force in at least two levels between high and low; A damping force adjustable hydraulic shock absorber having a damping force adjustable hydraulic shock absorber having a brake operation detection section that detects that the brake is actuated, and a damping force that is set to a low state other than high according to the selection of the changeover switch circuit. The present invention is characterized in that a control section is provided that preferentially increases the damping force when a detection signal is input from the brake operation detection section during switching. [Operation] With this configuration, the brake operation detection section monitors whether or not the brake is applied to the vehicle, and when a detection signal is input from the brake operation detection section to the control section, Even when the damping force of the hydraulic shock absorber is being switched to a low state other than high according to the selection of the changeover switch circuit, the control section preferentially sets the damping force to high (and improves the maneuverability of the vehicle. Stability is improved. [Example] Hereinafter, an example of the present invention will be explained based on the drawings. Figures 1 to 5 show a hydraulic shock absorber applied to this example. First, 1 in Figure 1 is a cylinder constituting the main body of the hydraulic shock absorber; one end of a piston rod 2 is provided in the cylinder 1 so as to protrude; the other end of the piston rod 2 is protruded outside the cylinder 1; The diameter of the area near the part is reduced to form a threaded part 2A.
is inserted into a hole in the vehicle body 3 and is fixedly attached with a lock nut 4. A piston 5 is fixed to the tip of the piston rod 2, and the piston 5 defines the interior of the cylinder 1 into chambers A and B. The piston 5 includes a disc valve, and the extension side serves as a fixed damping force generating mechanism that always generates a damping force having predetermined characteristics when the piston 5 is displaced in the extension direction and contraction direction together with the piston rod 2. A damping force generation mechanism 6 and a reduction side damping force generation mechanism 7 are respectively provided. Next, 8 indicates a cylindrical member fastened to the tip of the piston rod 2. The cylindrical member 8 functions as a lock nut for fixing the piston 5 etc. to the piston rod 2, and has a variable damping force inside. A storage chamber 9 is formed to house the generating mechanism. A closing plate 10 is attached to the distal end of the cylindrical member 8, and the storage chamber 9 is closed by the closing plate 10. Furthermore, a guide 13 consisting of a passage forming part 11 and a valve-shaped acid part 12 is fitted and fixed to the inner circumferential wall of the storage chamber 9 by means such as press fitting, and a shutter 14 is inserted and fitted inside the guide 13. has been done. The shutter 14 can be rotated while being guided by a guide 13, and a control rod 15 is provided to rotate the shutter 14. The control rod 15 has one end located outside the cylinder 1 and connected to a low actuator consisting of a solenoid, a stepping motor, etc., which will be described later, and the other end connected to an insertion hole formed in the axial center of the piston rod 2. 16 and extends into the storage chamber 9, and the shutter 14 is fixed to its tip. Further, an annular oil chamber 17 is formed between the cylindrical member 8 and the passage forming portion 11, and the oil chamber 17 and the chamber A are always in communication with each other via a communication hole 18. In addition, the passage forming part 1
As shown in FIG. 2, four orifice passages 19, 20, 21.22 each having a different flow area are bored in the orifice passage 1.
One end thereof opens into the oil chamber 17, and the other end opens into a contact surface with the shutter 14. And shutter 14
As shown in FIG. 3, a slit groove 23 is formed in the circumference of the barrel, and when the shutter 14 is rotated, the orifice passages 19 and 20 are selected.
It is selectively opened and closed so that the oil in the chamber A can be introduced into the internal oil chamber 24 of the shutter 14. Further, a plurality of oil chambers 25, 25, . . . are bored in the canopy of the shutter 14, and each oil chamber 25
A plurality of oil chambers 26.26. are bored in the valve-shaped acid part 12 through gaps between the canopy part and the inner surface of the valve-shaped acid part 12. ...
It communicates with Each oil chamber 26 is provided with a check valve 28 that allows oil to flow only from the oil chamber 26 toward the oil chamber 27 formed between the valve-shaped acid portion 12 and the cylinder member 8.
The check valve 28 is normally biased by a spring 29 in the direction of closing. Furthermore, the oil chamber 27 is connected to the piston rod 2.
It is constantly in communication with the oil chamber B via the insertion hole 16 provided in the axial direction thereof and the oil chamber 30 provided in the direction perpendicular thereto. Next, reference numeral 31 denotes an oil passage consisting of a concave groove formed on the outer peripheral surface of the circumferential body of the shutter 14, and the oil passage 31 can be selectively brought into communication with the orifice passages 21 and 22 by rotating the shutter 14. ing. An oil passage 32 is also formed on the outer peripheral surface of the valve-shaped acid part 12, and is always in communication with the oil passage 31 regardless of the rotational position of the shutter 14. Oil chamber 2 on the side
7 is in constant communication. The variable damping force generation mechanism formed as described above is
Communication hole 18. Oil chamber 17. Orifice passage 19 or 20
．． Oil chamber 25. Oil hole 26. Check valve 28. Oil chamber 27. A valve passage that communicates between the oil chambers A and B via the insertion hole 16 and the oil chamber 30, and the communication hole 18. Oil chamber 17. Orifice passage 21 or 22. Oil passage 31. Oil passage 32. Oil chamber 2
7. It is formed by the insertion hole 16 and a bypass flow path that communicates between the oil chambers A and B via the oil chamber 30, and the flow path area of the valve passage is regulated by the orifice passage 19 and 20. The flow path area is the orifice passage 21.
It is now regulated by 22. The passage areas of the orifice passages 19 and 21 are respectively larger than those of the orifice passages 20 and 22. Therefore, when the line connecting the slit groove 23 and the oil passage 31 of the shutter 14 is at the position (a) in FIG. Both are closed by the shutter 14, the variable damping force generation mechanism is in the fully closed position, and the damping force is hard.
When the shutter 14 is rotated by 60° to position (B) 7, the valve via passage opens with the passage area of the orifice passage 20, and the bypass passage opens with the passage area of the orifice passage 22. At this point, the damping force becomes normal. When the shutter 14 rotates further and reaches position (c),
The passage area of the valve via passage becomes the orifice passage 19, and the passage area of the bypass passage becomes the orifice passage 21, changing to a large passage position, and the damping force becomes soft. Next, 33 indicates a rotary actuator that switches and drives the damping force generation mechanism between soft, normal, and hard, and the low reactor 33 includes an actuator 33A consisting of a rotary solenoid, a stepping motor, etc.
It consists of a rotating shaft 33B, one end of which is attached to the actuator 33A and the other end of which is provided to protrude outside, and the other end of the rotating shaft 33B is connected to the control rod 15.
As a result, when the rotation shaft 33B rotates, the shutter 14 at the other end of the control rod 15 rotates, and the flow path area changes. Reference numeral 34 denotes a support for fixedly supporting the low reactor actuator 33, and the piston rod 2 is attached to the support 34.
A screw hole is formed to be screwed into the threaded portion 2A at the tip, and the support body 34 is fixedly screwed into the threaded portion 2A via a nut 35. Next, 36 in FIG. 6 is a changeover switch circuit, and the switch circuit 36 includes light emitting diodes 37 and 38 connected in parallel, and a resistor 39 connected in series to each of the diodes 37 and 38.
．． 40, a DC power supply 41 whose one side is connected in series with each of the diodes 37 and 38 and whose other side is grounded, and a soft contact 42A whose - side is grounded and whose other side is the resistor 39 side.
Or a normal-soft changeover switch 42 that selectively switches to the normal contact 42B on the resistor 40 side.
and a contact 4 connected between the resistor 39 and the contact 42A.
an output circuit 43 that outputs a signal "1" when the contact 2A is opened and a voltage is applied, and outputs a signal "0" when the contact 42A is closed and reaches the ground potential; the resistor 40 and the contact 42B; An output circuit 44 is connected between the output circuit 43 and outputs a signal "1" when the contact 42B is opened and a voltage is applied, similar to the output circuit 43, and outputs a signal "0" otherwise.
It is also configured. Here, when the changeover switch 42 is switched to the contact 42A by the driver's manual operation, a low damping force (soft) can be obtained by the control circuit described later, and when it is switched to the contact 42B, a medium damping force (soft) can be obtained. Normal). Reference numeral 45 denotes a detection unit, and the detection unit 45 includes a brake pressure sensor 46 for detecting the hydraulic pressure of the brake fluid sent from the mask cylinder, and a brake pressure sensor 46 connected to the brake pressure sensor 46 for detecting the hydraulic pressure of the brake fluid sent from the mask cylinder. an output circuit 4 that outputs a signal “1” when the value exceeds a predetermined value;
7, a vehicle speed sensor 48 that detects the vehicle speed, and a signal rl connected to the vehicle speed sensor 48 when the vehicle speed exceeds a predetermined value.
An output circuit 49 that outputs J, a steering wheel angle sensor 50 that detects the steering wheel angle, and a signal r that is connected to the steering wheel angle sensor 50 and outputs a signal r when the steering wheel angle exceeds a predetermined angle.
It is composed of an output circuit 51 that outputs lJ. 52 is a control section, and the control section 52 is connected to the output circuit 49.51, and both output circuits 49.51 receive the signal r.
an AND circuit 53 that outputs a signal "1" when lJ is output; and an OR circuit 54 that is connected to the AND circuit 53 and the output circuit 47 and outputs a signal rlJ when a signal "1" is input from at least one of them. is connected to the OR circuit 54 and the output circuit 43 of the switch switching circuit 36, and outputs the signal NJ when the signal "1" is input from one of the OR circuits 54 and 43. 55 and the OR circuit 54 and the output circuit 44 of the changeover switch circuit 36.
4 and output circuit 44 (signal "1" from one side)
an OR circuit 56 that outputs a signal rlJ when inputted, and a control circuit 57 connected to the OR circuits 56 and 55.
It is composed of. Here, the control circuit 57 connects signal lines 57A, 57B, 57C, 5
A signal is output through the OR circuit 55 and 56, and the control rod 15 is rotated by a predetermined angle according to the signal amount to obtain hard, normal, and soft damping force. The relationship between the input signal and the output signal from the control circuit 57 is shown in Table 1. Table 1 Relationship between the outputs of the OR circuits 55 and 56 and the outputs of the control circuit 57 The damping force adjustable hydraulic shock absorber according to this embodiment is constructed as described above, and its operation will be explained next. First, as shown in FIG. 6, the changeover switch 42 is connected to the normal contact 42B, and the output circuits 47, 49, 51 are connected to the brake pressure sensor 46, the vehicle speed sensor 48, and the steering wheel angle sensor 50. Suppose that all of them output a signal "0". In this case, the output circuit 43 of the changeover switch circuit 36 outputs the signal rlJ, and since the output circuits 47, 49, and 51 all output the signal "0", the OR circuit 54 outputs the signal rOJ. Then, the OR circuit 55 outputs a signal “l” to the control circuit 57. On the other hand, at this time, the output circuit 44 of the changeover switch circuit 36 outputs the signal "0", and the OR circuit 54 outputs the signal rOJ as described above.
The OR circuit 56 outputs a signal “0” to the control circuit 57. Therefore, the control circuit 57 rotates the low reactuator 33 so that the damping force adjustable hydraulic shock absorber generates a medium damping force according to Table 1. This causes the shutter 14 to move to the second
The state is at the small channel position (b) shown in the figure. When the piston rod 2 is extended in this state, the piston 5 is also displaced in the direction indicated by the arrow X in FIG. As a result, the pressure inside the oil chamber B becomes high, and this pressure flows into the oil chamber 27 via the oil filler 30 and the insertion hole 16. Here, since the check valve 28 is designed to prevent the flow of oil from the oil chamber 27 to the oil reservoir 26, no flow passage through the valve is formed. On the other hand, the oil in this oil chamber 27 flows through an oil passage 32, an oil passage 31, an orifice passage 2, which constitute a bypass flow path, as shown by arrow F in FIG.
2. The oil flows into the oil chamber A through the oil chamber 17 and the communication hole 18 sequentially, and a predetermined damping force is generated on the piston rod 2 by the hydraulic resistance force generated when flowing through the orifice passage 22 at this time. On the other hand, when the piston rod 2 and the piston 5 are displaced in the contraction direction as shown by the arrow Y in FIG. . The oil introduced into the oil chamber 17 passes through the orifice passage 22 to the oil passage 31, the oil passage 32, the oil chamber 27, and the insertion hole 16, as shown by arrow F2 in FIG.
The oil flows toward the oil chamber B through a bypass flow path consisting of the oil chamber 30 and the oil chamber 30, and at this time, a predetermined damping force is obtained by the hydraulic resistance force against the oil flowing through the orifice passage 22. At the same time, the oil in the oil chamber 17 flows into the shutter 14 from the slit groove 23 via the orifice passage 20.
Furthermore, the pressure acts on the check valve 28 through the oil chambers 25 and 26, and when this pressure becomes greater than the set pressure of the check valve 28 by the spring 29, the check valve 28 opens as shown by arrow F3 in FIG. The flow path via the valve will be opened. Next, the changeover switch 42 is artificially switched to the software contact 42A according to the driver's will, and the output circuits 47, 49.51 connected to the brake pressure sensor 46, vehicle speed sensor 48, and steering wheel angle sensor 50 are It is assumed that all the signals are outputting a signal "0". In this case, the output circuit 43 of the changeover switch circuit 36 outputs the signal "0", and the output circuits 47, 49, and 51 all output the signal rOJ, so the OR circuit 54 outputs the signal rOJ. Then, the OR circuit 55 outputs a signal “0” to the control circuit 57. On the other hand, at this time, the output circuit 44 of the changeover switch circuit 36 outputs the signal rlJ, and the OR circuit 54 outputs the signal rOJ as described above.
The OR circuit 56 outputs a signal “1” to the control circuit 57. Therefore, the control circuit 57 rotationally drives the low reactuator 33 so that the hydraulic shock absorber generates a low damping force according to Table 1. As a result, the shutter 14 is placed in the large flow path position (c). In this state, the bypass passage that is opened during both the extension stroke and the contraction stroke of the piston rod 2 comes to pass through the orifice passage 21, and the valve passage passage that is opened only during the extension stroke passes through the orifice passage 1.
9. and orifice passage 21.
Since the passage areas of 19 are larger than those of the orifice passages 22 and 20, the damping force characteristics on both the extension side and the contraction side are gentler than those at the small passage position (b). Change. Contact 42A of changeover switch 42 as described above. 42B to an appropriate position, a low or medium damping force is generated.However, as a result of switching the changeover switch 42 from the normal contact 42B to the soft contact 42A, the rotary Assume that the actuator 33 is in the middle of rotating the shutter 14 toward the large flow path position (c). Assume that in this state, the driver suddenly applies the brakes, so that the brake fluid pressure increases, the brake pressure sensor 46 detects this fluid pressure, and the output circuit 47 outputs the signal rlJ. In this case, since the output circuit 47 outputs the signal "1", the OR circuit 54 outputs the signal rlJ. Therefore, even if the signal rlJ is input to the OR circuit 56 and the signal "0" is input to the OR circuit 55, both the OR circuits 55 and 56 will output the signal "1" to the control circuit 57. Regardless of the switching position of the changeover switch 42, the control circuit 57 preferentially drives the low reactuator 33A to rotate so that the hydraulic shock absorber is placed in a high damping force state. As a result, the shack 14 is placed in the fully closed position (A). However, in this state, the valve passage and the bypass passage are not formed during either the extension stroke or the contraction stroke of the piston rod 2, so only the fixed damping force generation mechanism acts and the damping force characteristics change. becomes the largest. On the other hand, assume that the vehicle speed increases and the output circuit 49 outputs a signal "1" as a result of the vehicle speed detection by the vehicle speed sensor 48, and the output circuit 51 outputs a signal rlJ based on the rotation angle of the steering wheel angle sensor 50. In this case, since the input sides of the AND circuit 53 are both "1", the AND circuit 53 outputs a signal "1", and the signal is sent to each OR circuit 55, 56 via the OR circuit 54.
Input signal "1" to Therefore, in this case as well, the control circuit 57 operates regardless of the switching position of the changeover switch 42.
The rotary actuator 33 is rotationally driven to achieve a high damping force state. Therefore, the driver should, for example, change the damping force from normal to soft (by switching the changeover switch 42, and apply sudden braking while the shutter 14 is in the middle of rotation, or due to sudden steering at high speed, etc.). Hydraulic shock absorbers are able to generate high damping force preferentially even when the vehicle receives an impact force.For this reason, when braking suddenly, the vehicle body leans forward, which is the so-called r-nose dive. However, by preferentially switching the damping force to hard, it is possible to reliably prevent nose dive.Also, even when steering suddenly at high speed, it is possible to prevent so-called "spin" in which the vehicle body rotates. However, this spin can also be prevented because the high damping force state can be preferentially applied.As a result, the maneuverability and stability of the vehicle can be improved, and a comfortable ride can be ensured. In the embodiment, the changeover switch circuit 36 has two stages, soft and normal, but it may have three or more stages including hard.Also, in the embodiment, damping force adjustment in three stages has been described. , may be two stages (or may be four or more stages.Furthermore, in the embodiment, a vehicle speed sensor 48 and a steering wheel angle sensor 50 are added, and it has been described as being hard to switch even in the event of sudden notification at high speed. The processing at the time of sudden rotation may be omitted as appropriate. [Effect of the Invention 1] The damping force adjustable hydraulic shock absorber according to the present invention is as described above in detail, and the hydraulic shock absorber can be adjusted according to the will of the driver. If the brake operation detection unit detects that the vehicle has been braked while the damping force is being switched to a state other than high, the control unit is configured to preferentially switch to the high damping force state, so sudden braking is not possible. In some cases, hydraulic shock absorbers can quickly and stably maintain high damping force, reliably prevent the occurrence of nose dive phenomenon, and ensure vehicle maneuverability and stability. can.

[Brief explanation of the drawing]

1 to 6 show embodiments of the present invention, FIG. 1 is a sectional view of a main part of a hydraulic shock absorber, and FIG. 2 is an IT-I of FIG. 1.
A sectional view in the direction of the I arrow, FIG. 3 is an external view of the shutter, FIGS. 4 and 5 are explanatory diagrams of the operation of the variable damping force generation mechanism showing different operating states, and FIG. 6 is a changeover switch circuit and detection FIG. 3 is a circuit diagram showing the configuration of a control section and a control section. 36... Changeover switch circuit, 45... Detection section, 46
...Brake pressure sensor, 52...Control unit. Figure 2

Claims (1)

[Claims] A damping force adjustable hydraulic shock absorber capable of adjusting the damping force in at least two levels between high and low; and a damping force adjustable hydraulic shock absorber capable of adjusting the damping force by the hydraulic shock absorber to one of predetermined magnitudes according to the driver's will. A damping force adjustable hydraulic shock absorber having a selectable changeover switch circuit, wherein the damping force is switched to a low state other than high according to the selection of the changeover switch circuit. A damping force adjustable hydraulic shock absorber comprising: a control unit that preferentially increases the damping force when a detection signal is input from the brake operation detection unit during the brake operation.