JPH0424243B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shock absorber control device, and more particularly to one that increases the damping force of a shock absorber when a vehicle with an automatic transmission is in a stopped state.

[Prior Art] As is well known, the suspension of vehicles has a mechanism using a hydraulic shock absorber, which can be used alone or in combination with other springs, etc. to improve ride comfort and maneuverability. It becomes possible to obtain a suspension for a vehicle.

A typical hydraulic shock absorber includes a hydraulic piston interposed between the vehicle body side and the wheel side, and its damping force is always kept constant under certain conditions. That is, the damping force is normally determined by the cross-sectional area of an orifice through which fluid flows through two hydraulic chambers separated by a piston, and in conventional devices, the flow cross-sectional area of this orifice is constant. , the damping force under certain conditions was always kept constant.

[Problem to be solved by the invention] However, with such a constant damping force,
It is not always possible to achieve the optimum shock absorption effect when a vehicle is actually running, and according to the accumulated results of vehicle running experiments in recent years, it is preferable to change the damping force of the shock absorber according to various conditions. The conclusion has been reached.

In particular, in the conventional shock absorber mechanism mentioned above, its setting is adapted to normal constant speed driving conditions, so it is possible to shift from a non-driving force transmission shift position such as parking or neutral before starting the vehicle in an automatic vehicle. When changing to the drive shift position, a rotational driving force is suddenly applied to the shock absorber, causing a problem in which the vehicle body bends down to support this.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a device that can prevent a vehicle from becoming sluggish or sagging due to a shift position change before starting the vehicle.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a shock absorber control device for use in an automatic vehicle, which includes a damping force variable means for changing the damping force of the shock absorber, and a transmission mechanism. A drive shift position detection means detects that the shift position is in a state where the driving force of the vehicle is cut off, a start detection means detects that the vehicle is running, and a drive shift position detection means detects the state of the vehicle. The damping force of the shock absorber is increased when it is detected that the transmission of driving force is cut off, and the increased damping force is maintained at least until the start detection means detects that the vehicle is running. It is characterized by comprising a control means for controlling the damping force variable means.

[Function] The shock absorber control device according to the present invention has the above-described configuration, and detects that the drive force from the vehicle is not being transmitted to the tires by the drive shift position detection means. Sometimes, the damping force of the shock absorber is increased and controlled to be maintained at least until it detects that the vehicle is running. For this reason, when changing the shift position of an automatic vehicle from a state such as parking or neutral to a shift position such as drive range, this prevents the vehicle from becoming sluggish due to the drive torque transmitted to the vehicle. It can be prevented. Thereby, the ride comfort of the vehicle can be greatly improved.

[Embodiments] 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 14, and a hydraulic reserve chamber 200 is formed between the cylinders 12 and 14. Outer cylinder 14
A bottom plate 16 is hermetically fixed to the lower end of the , and a top plate 18 is similarly hermetically fixed to the upper end. The inner cylinder 12 has a bottom holder 20 fixed to its lower end.
It is housed and held within the outer cylinder 14 by a top holder 22 fixed to its upper end.

A piston 2 is disposed within the inner tube 12 of the cylinder 10.
4 is provided to be slidable in the axial direction, and the inside of the inner cylinder 12 is isolated by a piston 24 into a first hydraulic chamber 202 and a second hydraulic chamber 204.
The piston 24 is fixed to one end of a piston rod 26, the other end of which projects outwardly from the upper end of the cylinder 10. An oil seal 28 is provided between the piston rod 26 and the top plate 18 of the outer cylinder 14.
When the piston rod 26 slides in the axial direction, the hydraulic reservoir chamber 200 and the first hydraulic chamber 20
This prevents the pressure oil filled in the second and second hydraulic chambers 204 from leaking.

The piston 24 has a fixed orifice 3 on the extension side.
A variable orifice 32 on the zero and expansion sides is provided, and a contraction side check valve 31 is engaged with both orifices 30, 32 to determine the flow direction thereof. Similarly, the bottom holder 20 is provided with a fixed orifice 33 on the contraction side, a variable orifice 34 on the contraction side, and a check valve 35 on the expansion side. Therefore, when the piston 24 extends upward relative to the cylinder 10, the oil in the first hydraulic chamber 202 flows through the fixed orifice 30 on the extension side and the variable orifice 3 on the extension side.
2 to the second hydraulic chamber 204, and the damping force at this time is determined by the flow cross-sectional area of the fixed orifice 30 on the extension side in the low speed range, and by the flow cross-sectional area of the variable orifice 32 on the extension side in the middle and high speed ranges. Determined by the flow cross-sectional area. Similarly, the piston 24 is
On the other hand, when contracting downward, the second hydraulic chamber 20
4 flows into the first hydraulic chamber 202 through the fixed orifice 33 on the compression side and the variable orifice 34 on the compression side, and the damping force at this time is the damping force of the fixed orifice 33 on the compression side in the low speed range, and on the compression side in the medium and high speed range. They are each determined by the flow cross-sectional area of the variable orifice 34.

When the piston 24 expands and contracts, both hydraulic chambers 20
Oil from the hydraulic reservoir chamber 200 can also flow to 2, 204, and for this purpose, the bottom holder 20 and top holder 22 provided at the lower end of the inner cylinder 12 are provided with predetermined communication holes. There is.

The structure of the basic hydraulic shock absorber mechanism described above is the same as the conventional one, but in this embodiment, the shock absorber includes a variable orifice and a solenoid for operating the variable orifice.

That is, the outer tube 14 of the cylinder 10 has an open tube 14a formed on its side surface, and a plug 38 is airtightly 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 200 is connected and fixed between one end of the variable orifice 40 and the top holder 22, and the end of the conduit 42 on the top holder 22 side is connected to a communication port 22a formed in the top holder 22. It is connected to the first hydraulic chamber 202 via. Further, the other end of the variable orifice 40 communicates with the second hydraulic chamber 204 from the hydraulic reservoir 200 .

The plug 38 is formed with a slot 38a that crosses the variable orifice 40 in a direction perpendicular to the variable orifice 40, and the flow cross-sectional area of the variable orifice 40 is adjusted by changing the amount of blockage of the slot 38a. It becomes possible to do so.

In order to change the amount of blockage of the slot 38a, in the present invention, a solenoid 44 is incorporated and fixed in the shock absorber. That is, a case 46 of the solenoid 44 is fixed to the plug 38, a core 48 is fixed to the case 46,
Further, a coil 50 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. is inserted into the variable orifice 40
The cross-sectional area of flow is adjusted by the sliding position of the valve portion 52a.

In this embodiment, the valve portion 52 of the plunger 52
An open groove 53 is provided on the side surface of a.
When the coil 50 is in the de-energized state, the open groove 53 faces the variable orifice 40, as shown in FIG.
The damping force is determined to be a constant value by the flow cross-sectional areas of the variable orifice 40 and the orifices 30, 32 or 33, 34 provided in the variable orifice 40.

Then, when an excitation current is supplied to the coil 50 via a lead wire 56 from an excitation circuit, which will be described later, and the plunger 52 is attracted and moved toward the left in FIG. In this state, the shock absorber has a flow cross-sectional area equal to that of the orifice 30,
32 or 33, 34, and it becomes possible to temporarily change and adjust the damping force to a large extent.

Therefore, by energizing the solenoid coil 50 only when the vehicle is in a predetermined state, for example, when the vehicle is stopped, it is possible to obtain a good ride comfort. It is detected based on two conditions.

FIG. 2 shows a shift sensor 60 and a start sensor 6 as vehicle stop state detection means suitable for the present invention.
2 and control circuit 64 are shown.

The shift sensor 60 is provided in the transmission mechanism to detect a neutral shift position of the transmission mechanism, that is, a position other than the drive shift position such as parking or neutral. In this embodiment, the shift sensor 60 is turned on at the neutral shift position of the transmission mechanism. It is comprised of a neutral start switch 66 that outputs a neutral shift position signal 400 of "L".

On the other hand, the start sensor 62 is configured as follows in order to electrically detect the start of running of the vehicle.

That is, in order to electrically detect the running speed of the vehicle, the start sensor 62 includes a vehicle speed sensor 68, and the vehicle speed sensor 68 is composed of a rotor magnet and a reed switch that interlock with the wheels, and outputs a pulse signal with a frequency corresponding to the vehicle speed. It is output as a vehicle speed signal 402. A differentiation circuit 72 is provided on the output side of the vehicle speed sensor 68 via an F/V converter 70, and a vehicle acceleration comparison circuit 74 is provided on the output side of the differentiation circuit 72. Consisting of an amplifier 76, resistors 78, 80, and a capacitor 82, the vehicle acceleration comparison circuit 74 includes an operational amplifier 84,
It is composed of a resistor 86 and a variable resistor 88.

The vehicle speed signal 402 is transmitted to the F/V converter 7.
After being converted into a voltage signal at 0, it is detected as a differentiated vehicle acceleration by a differentiation circuit 72, and is further compared with a reference acceleration by a vehicle acceleration comparison circuit 74. When the acceleration falls below a predetermined value, the signal becomes "H". It is output to the AND gate 90 as a gate signal 404. Further, the vehicle speed signal 402 converted into a voltage signal by the F/V converter 70 is sent to an operational amplifier 92.
When the vehicle is running, a gate signal 406 of "H" is output from the operational amplifier 92 to the AND gate 90. Therefore, when the vehicle is running and the vehicle acceleration falls below a predetermined value, that is, when the vehicle is in a steady running state, both gate signals 404 and 406 are output to the AND gate 90, so that the AND gate 90 outputs " A start signal 408 of "H" is output.

Next, control circuit 64 outputs neutral shift position signal 40
0 and the start signal 402 to detect the drive shift position standby state of the vehicle and energize the coil 50 of the solenoid 44 to reduce the flow cross-sectional area of the variable orifice 40. There is.

That is, the neutral start switch 66
A neutral shift position signal 400 from the shift sensor 60 is supplied to a set input of a flip-flop (hereinafter referred to as "FF") 98 via a resistor 94 and an inverter 96. Since the neutral shift position signal 400 of "H" is supplied to the input, the Q output of the FF98 becomes "H". Also,
A coil excitation circuit 100 is provided on the Q output side of the FF98, and the coil excitation circuit 100 includes transistors 102 and 1 connected in series in the embodiment.
04, resistors 106 and 108, and a diode 110 for absorbing back electromotive force, transistors 102 and 104 are turned on by the "H" Q output of the flip-flop 98, and supply excitation current to the solenoid coil 50 for a predetermined time. do. Furthermore,
The start signal 408 from the start sensor 62 is supplied to the reset input of the FF98, and when the vehicle is running and the vehicle acceleration has reached a predetermined value, that is, when the vehicle is in a steady running state, the FF98 is activated.
Reset.

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

When the vehicle is stopped, the driver may place the transmission mechanism in the parking position or the neutral position. When the drive shift position is changed to a drive range or the like in order to start the next time in this state, the drive torque transmitted to the vehicle due to this change causes the vehicle to sag.

The characteristic feature of this embodiment is that the damping force of the shock absorber is increased in this drive shift position standby state, thereby preventing any distortion from occurring during the next drive position selection. .

That is, when the transmission mechanism is shifted to the neutral shift position, a neutral shift position signal 400 of "H" is supplied from the shift sensor 60 to the set input of the FF 98, and a "H" signal is supplied from the FF 98 to the coil excitation circuit 100.
Since the Q output signal is output, solenoid 4
An excitation current is supplied to the coil 50 of No. 4. Therefore, the plunger 52 of the variable shock absorber device shown in FIG. 1 is sucked and moved to the left in FIG.
0 is closed by the valve portion 52a, and in this state, the shock absorber device has a small flow cross-sectional area determined by the orifices 30, 32 or 32, 34, and the damping force is temporarily changed and adjusted to a large value. be able to. Therefore, when the shift position is in neutral or parking, the damping force of the shock absorber device can be increased. Therefore, when changing the shift position to a state that transmits driving force such as a drive range before starting the vehicle, the drive torque transmitted to the vehicle may cause a change in attitude (vehicle sagging phenomenon). can be prevented.

When the vehicle is running and the vehicle acceleration is below a predetermined value, that is, when the vehicle is in a steady running state, both gate signals 404 and 406 are output to the AND gate 90. A start signal 408 of "H" is supplied to the reset input. As a result, "H" is sent from the FF98 to the coil excitation circuit 100.
A Q output signal is output, and the supply of excitation current flowing to the coil 50 of the solenoid 44 is cut off, so the variable orifice 40 of the variable shock absorber device is opened again, and the damping force becomes small again, reducing the bumpy feeling while driving. etc. can be prevented from occurring.

As explained above, according to the present invention, by increasing the damping force of the shock absorber in the state where the transmission of the vehicle driving force is cut off before the vehicle starts, the shift position is changed to the state where the vehicle driving force is transmitted. It is possible to reliably prevent the vehicle from becoming sluggish due to the start of transmission of the drive torque in the case of the change, thereby improving the ride comfort of the vehicle.

In addition, in the above-mentioned embodiment, the shift sensor,
Although the stopped state of the vehicle is detected by the start sensor including the vehicle speed sensor, the stopped state of the vehicle may be detected using other methods, for example, a vehicle speed sensor or a shift sensor, each independently.

In addition, the shock absorber mechanism, which controls the damping force, may be installed on all four wheels, or only on the rear wheels, which have a large effect on the clinging phenomenon. Correspondingly, it is preferable to provide an arbitrary number of control circuits 64.

[Effects of the Invention] As explained above, according to the present invention, it is possible to temporarily increase the damping force of the shock absorber when the vehicle is stopped before starting the vehicle, thereby reliably preventing sagging. This makes it possible to significantly improve the ride comfort of the vehicle.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a shock absorber mechanism suitable for the apparatus of the present invention, and FIG. 2 is a circuit diagram showing a shift sensor, a start sensor, and a control circuit suitable for the present invention. 10... Cylinder, 12... Inner cylinder, 14... Outer cylinder, 24... Piston, 40... Variable orifice, 60... Shift sensor, 62... Start sensor, 64... Control circuit.

Claims (1)

[Scope of Claims] 1. In a shock absorber control device used in an automatic vehicle, the damping force variable means for changing the damping force of the shock absorber, and the shift position of the transmission mechanism are in a state where the driving force of the vehicle is cut off. a drive shift position detection means for detecting that the vehicle is running; a start detection means for detecting that the vehicle is running; and a start detection means for detecting that the drive shift position detection means detects that the transmission of the driving force of the vehicle is cut off. When the damping force of the shock absorber is increased,
A shock absorber control device comprising: control means for controlling said damping force variable means to maintain an increased damping force state at least until said start detection means detects running of the vehicle.