JPS5871210A - Shock absorber control of vehicle with ground clearance adjuster - Google Patents

Abstract

PURPOSE:To improve the ride comfortableness and the controllability of a vehicle with regard to a hydraulic shock absober described at the heading, by forming an orifice capable of varying the sectional area of an oil passage, increasing the flow sectional area of the orifice and reducing the damping force when a ground clearance adjusting air spring possesses the specified pressure. CONSTITUTION:By virtue of an increase of a load which is applied to a car's body, an air pressure in a ground clearance adjusting air spring not illustrated herein is increased, whereby the car's body may be prevented from sinking. If the air pressure reaches the specified value, a pressure switch not illustrated is turned on so that an exciting current is fed via a control circuit to a solenoid coil 50, which moves a plunger 52 of a variable capacity shock absorber device 64 to the left against a spring 54 to open a variable orifice 40 at a valve part 52a. The damping force of the absorber device 64 is thereby temporarily reduced so that tough feeling may be lessened. This structure may improve the ride comfortableness and the controllability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a shock absorber control device for a vehicle with a vehicle height adjustment device, in particular, a shock absorber control device for a vehicle equipped with a vehicle height adjustment device, in particular, by increasing the damping force of a hydraulic shock absorber. Obtaining absorber characteristics provides an additional benefit to the device.

The suspension of vehicles has a mechanism that uses a well-known hydraulic shock absorber, which can be used alone or
By using φ instead of using a spring of 1.5 cm, it is possible to obtain a suspension for a vehicle that has improved ride comfort and maneuverability.

Ordinary hydraulic/Yonk gamma pressor bar is ML body 11flj
The damping force of the hydraulic piston interposed between the front and the wheels is always kept constant under certain conditions. That is, the damping force is normally determined by the 1@ area of the orifice that flows through two hydraulic chambers separated by a piston, and in the conventional device, the +l ¥1 flow cross-sectional area of this orifice is constant. Therefore, the damping force under certain conditions was always kept constant.

However, such a constant damping force does not necessarily provide the optimal shock absorption effect when the vehicle is actually running, and according to the results of actual vehicle running in recent years, the shock absorber is adjusted depending on various conditions. It has been concluded that it is preferable to vary the damping force of the damping force.

In particular, the conventional shock absorber mechanism described above has the following problems because its setting is adapted to normal constant speed driving conditions.

In other words, a vehicle with a vehicle height adjustment device is provided with a vehicle height adjustment air spring to prevent the vehicle body from sinking when cargo is loaded or passengers get into the vehicle. When the load on the vehicle body increases, air flows in to increase the air pressure, and when the load decreases, air flows out to decrease the air pressure, thereby maintaining the vehicle height at a constant level. Normally, the vehicle body is suspended and supported by suspension blocks that hold the shock absorber device, vehicle height adjustment air spring, and support spring. It is determined in accordance with the conditions. Therefore, when the above-mentioned vehicle height adjusting air spring increases by 1f of air, the damping constant of the suspension block fluctuates, causing a bumpy feeling, resulting in poor ride comfort and maneuverability.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a vehicle weight adjustment device that can improve riding comfort and maneuverability by eliminating the rugged feeling that occurs when the air pressure of the vehicle height adjustment air spring increases. An object of the present invention is to provide a shock absorber control device for a vehicle with a motor vehicle.

In order to achieve the above object, the present invention includes a variable orifice that is incorporated into a hydraulic shock absorber and whose flow cross-sectional area can be finely adjusted in order to reduce the damping force of the shock absorber, and a A solenoid built into the shock absorber to change the cross-sectional area of the flow, a pressure gauge inch that detects the air pressure of the vehicle height adjustment air spring, and a pressure signal from the pressure gauge spring that indicates that the vehicle height adjustment air spring has reached a predetermined pressure. and a control circuit that excites the solenoid to increase the flow cross-sectional area of the variable orifice, and temporarily reduces the damping force of the shock absorber when the air pressure of the vehicle height adjustment air spring increases.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a preferred embodiment of a hydraulic shock absorber mechanism of a variable shock absorber device suitable for the present invention.

The cylinder 10 of the shock absorber has an inner cylinder 12 and an outer cylinder 1.
There is a hydraulic reservoir chamber 1 between the two cylinders 12 and 14.
00 is formed. A bottom plate 16 is hermetically fixed to the lower end of the outer cylinder 14, and a top plate 18 is similarly hermetically fixed to the upper end. The inner cylinder 12 is housed and held within the outer cylinder 14 by a bottom holder 20 fixed to its lower end and a top holder 22 fixed to its upper end.

A piston 24 is provided in the inner tube 12 of the cylinder 10 so as to be slidable in the axial direction thereof, and the inside of the inner tube 12 is separated by the piston 24 into a first hydraulic chamber 102 and a second hydraulic chamber 104. ing.

The piston 24 is fixed to one end of a piston rod 26, and the other end of the piston rod 26 projects outward from the upper end of the cylinder. An oil seal 28 is provided between the piston rod 26 and the top plate 18 of the outer cylinder 14.
6 slides in the axial direction, the hydraulic reservoir chamber 100,
This prevents the pressure oil filled in the first hydraulic chamber 102 and the second hydraulic chamber 104 from leaking.

The piston 24 is provided with an extension-side fixed orifice 3 ( ) and an extension-side variable orifice 32 , and a contraction-side check valve 31 is engaged with both orifices 30 , 32 to determine the direction of passage Me. ing. Similarly, the bottom holder 2o is provided with a fixed orifice 33 on the contraction side, a variable orifice 34 on the contraction side, and a check pulp 35 on the expansion side. Therefore, when the piston 24 extends in the vertical direction relative to the cylinder 1o, the oil in the first hydraulic chamber 102 moves through the fixed orifice 30 on the extension side and the variable orifice 32 on the extension side to the second hydraulic chamber 104. At this time, the damping force is determined by the flow cross-sectional area of the fixed orifice 30 on the extension side in the low speed range, and the damping force is determined by the flow cross-sectional area of the fixed orifice 30 on the extension side in the medium and high speed range.
It is determined by the flow cross-sectional area of 2. Similarly, when the piston 24 contracts downward with respect to the cylinder 10, the oil in the second hydraulic chamber 104 flows into the first hydraulic chamber 102 through the fixed orifice 33 on the contraction side and the variable orifice 34 on the contraction side. The damping force is the fixed orifice 33 on the compression side in the low speed range, and the variable orifice 3 on the compression side in the medium and high speed range.
4 will be determined by the flow cross-sectional area.

When the piston 24 expands and contracts, both hydraulic chambers 102.10
Oil from the hydraulic reservoir chamber 100 can also flow through the oil pressure reservoir chamber 100, and for this purpose, a bottom holder 20 and a top holder 22 provided at the lower end of the inner cylinder 12 are provided with predetermined communication holes. .

Although the structure of the basic hydraulic shock absorber groove described above is the same as the conventional one, the present invention is characterized in that the shock absorber is equipped with a variable orifice and a solenoid that operates the variable orifice. do.

That is, the outer tube 14 of the cylinder 10 has an open tube 14a formed on its 1111 surface, and a plug 38 is hermetically fixed to the open tube 14a.

A variable orifice 40 is provided in the plug 38 in parallel to the axial direction of the cylinder 10. A conduit 42 passing through a hydraulic reservoir chamber 100 is connected and fixed between one end of the 6f variable orifice 40 and the top holder 22.
A side end of the box boulder 22 is connected to the first oil chamber 102 via a communication port 2 a formed in the top holder 22.

Further, the other end of the variable orifice 40 communicates with the second hydraulic chamber 104 from the hydraulic reservoir chamber 1 (1(+).

The plug 38 is formed with a slot 38a that crosses the variable orifice 4o in a direction perpendicular to the variable orifice 4( ), and by changing the amount of blockage of the slot 38a, the flow cross-sectional area of the variable orifice 4o can be arbitrarily changed. In order to change the amount of closing of the slot 3Ba, a solenoid 44 is incorporated and fixed in the shock absorber in the present invention. That is, the case 46 of the solenoid 44 is fixed to the plug 38, and
A core 48 is fixed to the case 46, and a coil 5.0 is wound and fixed around the core 48. A plunger 52 is slidably housed in the core 48 and the plug 38 along the axis of the solenoid 44, and a valve portion 52a provided at the tip of the plunger 52 is inserted into the slot 38a of the plug 38. Inserted into the variable orifice 4
The flow cross-sectional area of .degree. is adjusted by the sliding position of the valve portion 52a. A spring 54 is provided between the plunger 52 and the core 48, and when no excitation current is supplied to the coil 50, the plunger 52 is urged to the right in the figure by the spring 54, and the variable orifice 40 is closed. be. Therefore, in this state, the hydraulic shock absorber performs the same function as a conventional device set to a constant damping force.

An excitation current is supplied to the coil 50 of the solenoid 44 from an excitation circuit, which will be described later, via a wire 56. In the illustrated embodiment, the solenoid 44 is a linear solenoid, and the excitation current to the coil 50 causes The biasing force of the sgel ring 54 and the emphasized position of the plunger 52 can be set, and thereby the variable orifice 40
It becomes possible to arbitrarily adjust the cross-sectional area of flow.

Therefore, the solenoid coil 50 has a small height rJ! 4 If you excite only when the air pressure inside the air spring increases,
By compensating for changes in the steering constant, it is possible to obtain good ride comfort and maneuverability without a bumpy feeling. In the present invention, the air pressure inside the Higashiko iiMI busy air spring is detected from a pressure switch.

FIG. 2 shows a schematic structure of a suspension block that suspends and supports a vehicle body, and FIG. 3 shows its equivalent circuit. As is clear from FIG. 3, the vehicle body 58 has support springs 6
0. The vehicle height adjusting air spring 62 is suspended between a vehicle height adjusting air spring 62 and a shock absorber Wt64.The vehicle height adjusting air spring 62 has an air vibro 4.66 that guides air intake and exhaust.

A pressure switch 68 is provided in any of the air vibrators 4 (66) of the vehicle height adjusting air springs 62 to detect the air pressure within the vehicle height adjusting air spring 62. As shown in FIG. 4, the pressure switch 68 indicates that the air pressure inside the vehicle height adjustment air spring 62 is 8 [kg/cd'].
It is configured to turn on when s (kg/cdl), and turn off when s (kg/cdl), and this hysteresis characteristic causes the solenoid excitation action to be repeated...the pinching phenomenon is prevented. There is.

A preferred embodiment of the pressure switch 68 and control circuit 70 is shown in FIG.

In the figure, a control circuit 70 operates a solenoid coil 50 based on a pressure signal 200 from a pressure switch 68 when the air pressure within the vehicle height adjustment air spring 62 reaches a predetermined value (8 [kg/7''J in this embodiment). It is provided to control the flow cross-sectional area of the variable excitation orifice 40, and is configured as follows.In other words, the control circuit 70 in the embodiment 2 is composed of transistors connected in series. 72.74, a resistor 76.78, and a diode 80 for absorbing back electromotive force. An excitation current is supplied to the time solenoid coil 50. Still, the pressure signal 200 is
When it becomes "L", the transistors 72 and 74 are turned off,
The supply of excitation current to the solenoid coil 50 is cut off.

The embodiment of the present invention has the above configuration, and its operation will be explained below using Iu.

When the load applied to the heavy body 58 increases, such as when a vehicle with a vehicle height adjustment device is loaded with luggage or a passenger gets into the vehicle, air is introduced into the air spring 62 for vehicle height adjustment using the air vibro 4, and air is introduced into the air spring 62 for vehicle height adjustment. The air pressure within the air spring 62 increases, and as a result, it is possible to prevent the heavy body from sinking.

However, as the air pressure inside the vehicle height adjustment air spring 62 increases, the suspension block turning constant changes, so if the vehicle is driven in this state, it will feel bumpy, resulting in poor ride comfort and maneuverability. Become.

In the present invention, the variation in the damping constant due to the increase in air pressure in the vehicle height adjusting air spring 62 is compensated for by adjusting the damping force of the shock absorber device 64 in order to prevent the occurrence of the bumpy feeling. That is, when the air pressure inside the vehicle height adjustment air spring 62 increases to a predetermined pressure (in this embodiment, 8 [kg/(i])) at which a bumpy feeling occurs, the pressure Kasuinochiro 8 is turned on and the control circuit 70 is turned on.
(A pressure signal 200 of 2HJ is output. In response, the transistors 72 and 74 of the control circuit 70 are turned on, and an excitation current is supplied to the solenoid coil 50.

Therefore, the plunger 52 of the oJ variable shock absorber device 64 shown in FIG. 1 is sucked and moved to the left in FIG. The absorber device 64 has an increased flow cross-sectional area, and can temporarily change and adjust the damping force to a smaller value. As a result, it is possible to prevent the occurrence of a bumpy feeling when traveling with a load of a predetermined value or more applied, and it is possible to improve ride comfort and maneuverability.

Next, when the load applied to the vehicle body 58 decreases, air is discharged from the vehicle height adjustment air spring 62 through the air vibro (), and the air pressure within the vehicle height adjustment air spring 62 decreases, causing the vehicle body 58 to rise. can be prevented.

At this time, the damping constant changes due to the decrease in the air pressure inside the vehicle height adjustment air spring 62, resulting in a fluffy feeling.However, in the present invention, the damping constant due to the decrease in the air pressure inside the vehicle height adjustment air spring 62 changes. The fluctuation of 7
It is possible to prevent the occurrence of a fluffy feeling by properly compensating for the damping force adjustment of the Yokubububu device 64. That is, the air pressure in the vehicle height adjustment air spring 62 is set to a predetermined pressure (5 kg/cd in this embodiment) at which a fluffy feeling is generated.
]), the pressure switch 68 is turned off and a pressure signal 200 of "rL" is output to the control circuit 70.

Accordingly, the transistor OFF 2.74 of the control circuit 7o is turned off, and the supply of excitation current to the solenoid coil 50 is cut off. Therefore, the plunger 52 of the variable yoke absorber device shown in FIG. 1 is moved to the left in FIG. 1 by the biasing force of the spring 54, and the variable orifice 40) is closed by the i valve portion 52a. In this state, the shock absorber device 64 has a reduced flow cross-sectional area, and the damping force can be adjusted to a large extent, so that the occurrence of a stiff feeling during driving can be prevented.

As explained above, according to the present invention, by temporarily reducing the damping force of the shock absorber when the air pressure of the air spring for adjusting the vehicle height increases, the bumpy feeling during driving can be reduced by 4.
〈It can improve ride comfort and maneuverability 1゜

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of a shock absorber mechanism suitable for the device of the present invention, Fig. 2 is a schematic configuration diagram of a suspension block, Fig. 3 is an equivalent circuit diagram of Fig. 2, and Fig. 4 is a pressure switch. FIG. 5 is a circuit configuration diagram showing a pressure switch and a control circuit suitable for the present invention. 10...Cylinder", 12...Inner cylinder, 14
... Outer cylinder, 24 ... Piston, 40.
...Variable orifice, 62...Air spring for vehicle height adjustment,
68...pressure switch, 70...1ljl)
(ill1 circuit, 200...pressure signal.

Claims (1)

[Claims] (+) A variable orifice that is incorporated into a hydraulic shock absorber and whose flow cross-sectional area can be adjusted to a greater extent in order to reduce the damping force of the shock absorber, and for changing the flow cross-sectional area of the variable orifice. A solenoid built into the shock absorber, a pressure switch that detects the air pressure of the vehicle height adjustment air spring, and a variable orifice that energizes the solenoid when the vehicle height adjustment air spring reaches a predetermined pressure based on the pressure signal from the pressure switch. The street f
A shock absorber control device for a vehicle with a vehicle height adjustment device, comprising: a control circuit for increasing the cross-sectional area; .