JPH02213768A - Acceleration and deceleration detector for vehicle - Google Patents

Abstract

PURPOSE:To eliminate the need for the computation of respective input values by a computer and to reduce the cost by detecting acceleration and deceleration states by a change in the oil pressure of a hydraulic cylinder by the inertia force of a power unit generated at the time of acceleration and deceleration. CONSTITUTION:The power unit 3 consisting of a vertically placed engine 3a and a speed change gear 3b connected to the rear of the engine 3a, etc., is mounted in an engine room 2b in the front part of a vehicle body 2. This power unit 3 is mounted oscillatably via a cushion member 3c on the vehicle body 2 so that the oscillation of the power unit 3 is not transmitted to the body 2. Either of a piston rod 26 of a hydraulic cylinder 12 or cylinder body 13 is connected to the power unit 3, as well the other one is connected to the body 2. The piston rod 26 is extended or contracted by the inertia force of the power unit 3. The acceleration and deceleration are thereby detected by a change in the oil pressure.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for detecting acceleration and braking states of a motor vehicle, and particularly to a device for reducing the cost of the detection device by adopting a novel detection method. Regarding the structure.

[Conventional technology]

When a running car suddenly comes to a stop, a so-called nose dive phenomenon occurs in which the front part of the car body sinks and the rear part lifts up due to the load shift, causing the problem that the posture of the vehicle becomes unstable. To prevent such nose dive phenomenon,
Conventionally, an attitude control device has been employed that detects a sudden braking state of a vehicle and increases the damping force of a shock absorber of a suspension system at the time of detection (for example, Japanese Patent Laid-Open No. 6
1-44014. Japanese Patent Publication No. 61-67607. Japanese Unexamined Patent Publication 1986
-283009 Publication), an acceleration/deceleration detection device that detects the acceleration/deceleration state of the vehicle is indispensable for such an attitude side m device, and as a method for detecting such acceleration/deceleration state, conventionally, for example, a vehicle speed sensor is used. The signal is input to a microcomputer to determine its rate of change, and when this rate of change exceeds a predetermined set value, it is determined that sudden acceleration is occurring, or changes in brake oil pressure or height between the vehicle body and the road surface are detected. An electronic control method is employed in which changes are detected by sensors, and when these detected values exceed a predetermined set value, it is determined that sudden braking is occurring. Note that methods for detecting acceleration at the time of sudden start using an accelerometer, the amount of depression of the accelerator pedal, etc. have also been adopted.

[Problem that the invention seeks to solve]

By the way, the conventional method for detecting acceleration/deceleration states is as follows:
The problem is that costs increase because the electronic control method inputs electrical signals from each sensor, etc. to a micro combinator, calculates each human power value on a computer, and determines whether or not it is in an acceleration/deceleration state. There is a point.

An object of the present invention is to provide a vehicle acceleration/deceleration detection device that can reduce costs by eliminating the need for a computer to calculate each input value.

Means for Solving Problem C] The inventor of the present invention observed the state of the vehicle when acceleration/deceleration occurs, and found that the power unit such as the engine is equipped with a buffer member to prevent vibrations from being transmitted to the vehicle body. Focusing on the fact that it is mounted so that it can swing, we came up with the idea that if we could detect acceleration and deceleration using the inertial force of the power unit that occurs when the vehicle accelerates and decelerates, we could eliminate the need for detection using electrical signals from sensors, etc. This is what constitutes the present invention.

Therefore, the present invention connects one of the piston rod or the cylinder body of a hydraulic cylinder to a power unit swingably mounted on the vehicle body, and connects the other to the vehicle body, so that the inertia of the power unit generated when the vehicle accelerates or decelerates This is an acceleration/deceleration detection device for a vehicle, characterized in that the piston rod is expanded and contracted, and acceleration/deceleration is detected based on changes in oil pressure caused by this.

Here, when the hydraulic cylinder is disposed between the power unit and the vehicle body, it is preferable that the crankshaft is mounted with the crankshaft facing in the longitudinal direction of the vehicle, and the cylinder is arranged in the direction of the crankshaft.

[Effect]

According to the acceleration/deceleration detection device for a vehicle according to the present invention, the acceleration/deceleration state is detected by the change in the oil pressure of the hydraulic cylinder due to the inertial force of the power unit that occurs during acceleration/deceleration, so that the electric An electronic device for processing signals using a microcomputer or the like can be eliminated, and costs can be reduced accordingly. Furthermore, since the structure is such that hydraulic pressure is generated by the inertial force, when the detection device of the present invention is applied to, for example, a vehicle attitude control device, the hydraulic pressure generated by the inertial force damps the displacement absorber of the suspension system. It can also be configured to switch the force to the hard side, and nose dive etc. can be prevented with a simple and low cost device.

Further, in the present invention, a damping function can be easily added by providing an orifice in the hydraulic piston, and in this case, the effect of suppressing vibration of the power unit can also be obtained.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 3 are diagrams for explaining a vehicle acceleration/deceleration detection device according to an embodiment of the present invention. In this embodiment, the acceleration/deceleration detection device described above is directly applied to an automobile attitude control device. will be explained using an example.

In Fig. 3, numeral 1 is a car, and inside the enfucius room 2b at the front of the car body 2 is a vertical! A power unit 3 is mounted, which includes an engine 3a, a transmission 3b connected to the rear of the engine 3a, and the like. This power unit 3 is swingably attached to the vehicle body 2 via a buffer member 3c, so that vibrations of the power unit 3 are not transmitted to the vehicle body 2. Also,
A rear wheel suspension system 4 is disposed on a rear wheel 6 disposed at the rear of the vehicle body 2. This suspension system 4 is connected to the vehicle body 2,
It is disposed between an axle 2a disposed below the vehicle body 2 in the vehicle width direction, and is composed of a coil spring 4a and a four-wheel absorber 5.

As shown in FIG. 1, the above-mentioned displacement absorber 5 has a piston 9 that can move forward and backward into a cylinder 7 filled with oil.
the lower part 8a of the piston rod 8 into the piston 9.
while fixing the upper part 8b of the piston rod 8.
The cylinder 7 is configured to project outward from the cylinder 7. Further, the lower end of the cylinder 7 is pivotally supported by the support bracket of the rear wheel 6, and the upper end 8b of the piston rod 8 is connected to the support bracket of the rear wheel 6.
is mounted on the vehicle body 2 via a bracket (not shown).

Further, an orifice hole 1O is formed to penetrate in the axial direction in the piston 9, and the orifice hole 1O is used to communicate oil from one oil chamber to the other oil chamber of the cylinder 7 divided by the piston 9. belongs to. Further, on the upper and lower surfaces of the piston 9 of the piston rod 8, a disc-shaped opening/closing valve 20a for opening and closing the orifice hole 10,
20b is attached, and the respective closing valves 20a, 20b are urged in the closing direction by springs 21a, 21b. As a result, the on-off valves 20a and 20b are configured to increase the oil flow rate passing through the orifice hole IO when the piston rod 8 contracts, and to decrease the oil flow rate when the piston rod 8 extends. As a result, the vibration of the coil spring 4a is damped.

Further, an oil hole 15 is provided in the axis of the piston rod 8.
A2 and the oil hole 15a are followed by a piston insertion hole 15b having a slightly larger diameter. This insertion hole 15b
A pressing piston 16 is inserted into the interior so that it can move forward and backward.
A return spring 18 is provided between the pressing piston 16 and a plug nut 17 screwed onto the lower end of the piston rod 8.
is installed. Further, a long hole 19 is formed in the axial direction in the portion of the piston rod 8 facing the pressing piston 16, and a plate-shaped pressing member 22 formed in the shape of a hook is disposed within the long hole 19. It is set up.

The inner end 22a of this pressing member 22 is connected to the pressing piston 16.
The outer end 22b, which is bent downward, protrudes outward from the piston rod 8.

Further, an axially slidable sleeve 23 is attached to the lower part of the elongated hole 19 of the piston rod 8, that is, below the outer end 22b, and the sleeve 23 biases the on-off valve 20a. Spring 21M is locked. As a result, when hydraulic pressure is applied to the pressing piston 16, the pressing member 22 pushes down the sleeve 23, and the opening/closing valve 2
A posture control device is configured in which 0M closes the orifice hole 10 and puts it into a locked state.

One end 25a of a hydraulic supply pipe 25 is connected to the oil hole 15a at the upper end of the piston rod 8, and the other end 25b
is the first cylinder of the hydraulic cylinder 12 of the acceleration/deceleration detection device 11 disposed in the engine room 2b. second hydraulic chamber 12a,
12b via switching valves 36a and 36b, respectively.

The switching valves 36a and 36b are arranged in a second position and a first position, respectively.
The hydraulic pressure in the hydraulic chambers 12b and 12a is supplied as pilot pressure, and when the biloft pressure becomes high, each of the hydraulic chambers is configured to be switched to the closed side.

The acceleration/deceleration detection device 11 is constructed by installing a hydraulic cylinder 12 between the power unit 3 and the dash panel 2d of the vehicle body 2. The hydraulic cylinder 12 has an orifice hole 1 in a cylinder body 13 filled with oil.
A piston 14 having a groove 4a formed therein is inserted so as to be movable in the axial direction, one end of a piston rod 26 is fixed to the piston 14, and the other end of the rod 26 is made to protrude outward in the axial direction. Further, the rear end of the cylinder 13 is mounted pivotally on the dash panel 2d via a metal fitting 27,
The protruding end of the piston rod 26 is attached to a boo racket 28.
The power unit 3 is pivotally supported via the power unit 3. moreover,
The other end 25b of the hydraulic pressure supply pipe 25 is branched and connected to the front and rear parts of the cylinder 130 of the vehicle. As a result, the piston rod 26 expands and contracts due to the inertial force when the power unit 3 takes an image between the front and rear of the vehicle body, and the hydraulic pressure generated thereby detects acceleration and deceleration. is configured so that it can be switched to a locked state.

Next, the effects of this embodiment will be explained.

In this embodiment, when the car 1 is suddenly braked while the car 1 is running and the car 1 suddenly decelerates, the power unit 3 moves forward due to inertia force, and the piston rod 26 is pulled forward, so the cylinder 13 Hydraulic pressure corresponding to sudden braking is generated in the front oil chamber 12b, and sudden braking is thereby detected. Then, the switching valve 36a is closed by this oil pressure, and the pressing piston 16 of the shock absorber 5 pushes down the sleeve 23, whereby the on-off valve 20a closes the orifice hole 10 and is in a substantially locked state. Then, the flow of oil in the cylinder 7 is blocked, and the rear wheel 6. The weight of the axle 21 and the like is directly added to the vehicle body 2, and the sprung mass increases accordingly, making it possible to suppress lifting of the rear portion of the vehicle and stabilize the behavior of the vehicle body.

In addition, during sudden acceleration, the power unit 3 vibrates rearward, hydraulic pressure is generated in the rear hydraulic chamber 12a of the cylinder 13, and the cylinder absorber 5 is substantially locked as in the case of sudden braking described above, causing the rear of the vehicle to sink. is suppressed, and the behavior of the vehicle can be stabilized in this case as well.

In this embodiment, the hydraulic piston 12 is disposed between the power unit 3 and the dash panel 2d of the vehicle body 2, and the piston rod 26 is moved back and forth by the inertia of the power unit 3 during sudden braking or sudden acceleration. Due to this change in oil pressure, sudden braking or sudden acceleration is detected, and this oil pressure is used to lock the damping force of the seat absorber 5.
Compared to the case of employing a microcomputer or the like as in the above-mentioned conventional publication, the behavior of the vehicle can be stabilized while reducing costs.

Further, in this embodiment, the piston 14 of the hydraulic piston 12
Since the orifice hole 14a is provided in the power unit 3
This also has the effect of suppressing vibrations.

FIG. 4 shows another embodiment, in which a separate hydraulic power source is provided.

In the figure, the same reference numerals as in Figure 1 indicate the same or corresponding parts, and 3
1, 32, and 33 are a hydraulic supply tank, a hydraulic pump, and a reservoir tank, respectively. The hydraulic pressure supply tank 31 and the oil hole L5a are connected by a hydraulic pressure supply pipe 25, and the oil hole 15a and the reservoir tank 33 are connected by a return passage 35. A switching valve 34a is provided in the middle of the hydraulic supply pipe 25 and the return passage 35.

34b is provided, and each switching valve 34a,
A pilot passage 36 from the hydraulic cylinder 26 is connected to 34b. Note that 25c is a check valve.

In this embodiment, when the hydraulic pressure of the hydraulic cylinder 12 reaches a predetermined value, the switching valve 34m is switched open, and the hydraulic pressure from the hydraulic pump 32 is transferred to the mushroom absorber 5.
is supplied to

In the above embodiment, the case where the acceleration/deceleration detection device 11 is connected to an attitude control device for preventing nose dive has been explained as an example, but the acceleration/deceleration detection device of the present invention can of course be used with other control devices.
It may be connected to the device.

(Effects of the Invention) As described above, according to the vehicle acceleration/deceleration detection device according to the present invention, one end of the hydraulic cylinder is connected to the lateral movable power unit, the other end is connected to the vehicle body, and the power unit is connected to the vehicle body. Since the oil pressure in the hydraulic cylinder is changed by inertia force, acceleration and deceleration can be detected by changes in the oil pressure, eliminating the need for electronic control and reducing costs.

[Brief explanation of the drawing]

1 to 3 are diagrams for explaining an acceleration/deceleration detection device according to an embodiment of the present invention, and FIG. 1 shows a case where the acceleration/deceleration detection device of this embodiment is connected to a vehicle attitude control device. Fig. 2 is a partial sectional view showing the shock absorber locked due to sudden braking, Fig. 3 is a side view of an automobile in which the acceleration/deceleration detection device is adopted, Fig. 4
The figure is a piping system diagram showing another embodiment. In the figure, 1 is an automobile (vehicle), 2 is a vehicle body, 3 is a power unit, 11 is an acceleration/deceleration detection device, 12 is a hydraulic cylinder, 13 is a cylinder body, 14 is a piston, and 26 is a piston rod. Patent applicant: Daihatsu Motor Co., Ltd. Agent Patent attorney Draft: Tsutomu Figure 3 Figure 4

Claims (1)

[Claims] (1) One of the piston rod or cylinder body of a hydraulic cylinder is connected to a power unit swingably mounted on the vehicle body, and the other is connected to the vehicle body, and the inertia of the power unit generated when the vehicle accelerates or decelerates 1. An acceleration/deceleration detection device for a vehicle, characterized in that a piston rod is expanded and contracted, and acceleration/deceleration is detected based on changes in oil pressure caused by the expansion and contraction of a piston rod.