JP5182667B2 - Suspension device - Google Patents

Description

  The present invention relates to an improvement of a suspension device.

  Conventionally, a first pipe that allows a working fluid to flow between an upper chamber of a fluid pressure cylinder provided between the vehicle body and the left wheel and a lower chamber of the fluid pressure cylinder provided between the vehicle body and the right wheel. A second pipe that allows a working fluid to flow between an upper chamber of a fluid pressure cylinder provided between the vehicle body and the right wheel and a lower chamber of the fluid pressure cylinder provided between the vehicle body and the right wheel. A suspension device is known that suppresses the roll of the vehicle by controlling the flow of the working fluid that flows through each pipe based on the vehicle information. In this type of suspension device, when the working fluid leaks, the steering stability is greatly impaired. Therefore, a suspension device that determines whether there is a leakage of working fluid in each pipe based on the difference between the estimated pressure inside each pipe estimated based on the vehicle information and the measured pressure inside each pipe measured by the pressure sensor Has been developed (see, for example, Patent Document 1).

By the way, the pressure inside each pipe rises as the temperature of the working fluid rises, and the temperature of the working fluid changes due to vehicle motion, road surface input, outside air temperature, and the like. Therefore, in the suspension device that determines that the working fluid leaks when the pressure of the working fluid in each pipe falls below a predetermined value, if the temperature of the working fluid is high, the pressure of the working fluid is high. It is difficult to determine a simple leak. Although the temperature of the working fluid is required as a parameter in order to increase the leakage determination accuracy, the addition of a dedicated temperature sensor causes an increase in manufacturing cost and a complicated structure.
Table 2004/080735

  Therefore, an object of the present invention is to provide a suspension device with improved accuracy in determining the leakage of working fluid.

In order to solve the above-described problems, a suspension device according to claim 1 of the present invention is provided between at least one first fluid pressure cylinder provided between a vehicle body and a left wheel, and between the vehicle body and a right wheel. At least one second fluid pressure cylinder provided; a first pipe that allows a working fluid to flow between an upper chamber of the first fluid pressure cylinder and a lower chamber of the second fluid pressure cylinder; and the second A second pipe that allows the working fluid to flow between the upper chamber of the fluid pressure cylinder and the lower chamber of the first fluid pressure cylinder; and a first pressure measurement that measures the pressure of the working fluid inside the first pipe. And a second pressure measuring means for measuring the pressure of the working fluid in the second pipe, and calculating a relative speed of the vehicle height from vehicle height data obtained from the vehicle information, Average speed Estimating the temperature change amount of the working fluid within the pipes based on the relative velocity of the averaged vehicle height, the fluid temperature estimation for estimating the temperature of the working fluid in the pipes based on the the outside temperature each estimated result Means, fluid pressure estimation means for estimating the pressure of the working fluid in each pipe based on the estimation results of the fluid temperature estimation means, the estimation results of the fluid pressure estimation means, and the first and second pressure measurements And determining means for calculating a difference between each measurement result of the means and determining whether there is a leakage of the working fluid in each pipe based on each calculation result.

  ADVANTAGE OF THE INVENTION According to this invention, the suspension apparatus which improved the determination precision of the leakage of a working fluid can be provided.

A first embodiment of the present invention will be described with reference to FIG.
The suspension device has a second fluid pressure provided between each upper chamber of the first fluid pressure cylinders 1 and 2 provided between the vehicle body and the left front wheel and the left rear wheel, and between the vehicle body and the right front wheel and the right rear wheel. First piping 5 allowing the flow of working fluid between the lower chambers of cylinders 3 and 4, upper chambers of second fluid pressure cylinders 3 and 4, and lower chambers of first fluid pressure cylinders 1 and 2 And a second pipe 10 that allows the working fluid to flow there between. The first pipe 5 includes a damping valve 6, an on-off valve 7, a relief valve 8, and a pressure sensor 9 (first pressure measuring means), and is connected to a temperature compensating accumulator 15. The second pipe 10 includes a damping valve 11, an on-off valve 12, a relief valve 13, and a pressure sensor 14 (second pressure measuring means), and is connected to a temperature compensating accumulator 15.

The suspension device includes vehicle information such as vehicle height, longitudinal acceleration, lateral acceleration, vehicle speed, steering steering angle, steering steering angular velocity, engine speed, brake ON / OFF, throttle opening, outside air temperature, and pressure sensor 9, 14 includes a control device 16 including a microcomputer that controls the on-off valves 7 and 12 based on the pressure of the working fluid in the pipes 5 and 10 detected by the pipe 14. Incidentally, of vehicle height of the vehicle information is obtained from the detection result of the vehicle height detecting sensor.

Next, the control flow of the control device 16 will be described with reference to FIGS.
FIG. 2 shows a main flow of the control device 16. When the power is turned on, the control device 16 is first initialized (step 1). Next, it is determined whether or not it is the next control cycle (step 2). Here, if it is determined that the next control cycle is reached (YES in step 2), the processing result in the previous control cycle is output to the actuator (step 3), and further output processing is performed (step 3). 4). If it is determined in step 2 that it is not the next control cycle (NO in step 2), the process returns to step 2. Next, vehicle information is read (step 5), and on-off valves 7 and 12 are controlled based on the read vehicle information (step 6). Further, another calculation process is executed, a necessary control current is calculated (step 7), and the process returns to step 2.

  FIG. 3 shows a control flow of the on-off valves 7 and 12 in step 6. When the control flow of the on-off valves 7 and 12 is called in the main flow shown in FIG. 2 (step 20), the pressure P1 of the working fluid in the first pipe 5 and the pressure P2 of the working fluid in the second pipe 10 (hereinafter referred to as the following). , P1 and P2 are referred to as system pressure), a fail determination process for determining whether or not is in a fail state (steps 21, 22). Here, when it is determined that it is not in the fail state (YES in Step 22), the normal control of the on-off valves 7 and 12 is performed (Step 23). In addition, when it determines with it being in a fail state in step 21 (NO of step 22), both the on-off valves 7 and 12 are closed (step 24).

  FIG. 4 shows a fail determination process flow in step 21. When the fail determination processing flow is called in the control flow of the on-off valves 7 and 12 shown in FIG. 3 (step 30), the reference vehicle height data is subtracted from the vehicle height data obtained from the vehicle information, and the relative displacement of the vehicle height. Is calculated (step 31). Next, the calculation result of the relative displacement of the vehicle height is differentiated to calculate the relative speed of the vehicle height (step 32). Next, moving average processing is performed so that the calculation result of the relative speed of the vehicle height corresponds to the change speed equivalent to the temperature change of the working fluid (step 33), and the temperature change coefficient is added to the averaged relative speed of the vehicle height. By multiplying, the temperature change amount of the working fluid in each of the pipes 5 and 10 is estimated (step 34). Further, the estimated temperature change amount of the working fluid and the outside air temperature data obtained from the vehicle information are processed to estimate the temperature of the working fluid (step 35).

Then, the estimated result of the temperature of the working fluid is processed and the system pressure is estimated (step 36). Next, the actually measured system pressure detected by the pressure sensors 9, 14 is subtracted from the estimated system pressure (step 37). Then, the differential pressure between the estimated system pressure and the actually measured system pressure is compared with the threshold value at the estimated temperature of the working fluid obtained in step 35 (step 38), and when the differential pressure is not more than the threshold value (YES in step 38) ), The fail flag is cleared, that is, it is determined that there is no leakage in the pipes 5 and 10 (step 39). When the differential pressure is larger than the threshold value in step 38 (NO in step 38), it is determined that the fail flag is set, that is, there is a leak in the first pipe 5 or the second pipe 10 (step 40). ). Here, steps 34 and 35 are fluid temperature estimating means, step 36 is a fluid pressure estimating means. Steps 37 to 40 are determination means.

  The threshold value in step 38 is set based on a table represented by the map of FIG. 5 stored in the storage area of the control device 16.

The first embodiment has the following effects.
According to the first embodiment, the differential pressure between the estimated system pressure and the measured system pressure is compared with a threshold value, and when the differential pressure is equal to or less than the threshold value, it is determined that there is no leakage in each of the pipes 5 and 10 When the differential pressure is greater than the threshold value, it is determined that there is a leak in the first pipe 5 or the second pipe 10. And in 1st Embodiment, the temperature of the working fluid in each piping 5 and 10 is estimated, and the pressure of the working fluid in each piping 5 and 10 is estimated based on this estimation result.
Therefore, it is possible to provide a suspension device with higher accuracy in determining the leakage of the working fluid in the pipes 5 and 10 than when the temperature of the working fluid is not taken into consideration. Further, according to the first embodiment, since the temperature of the working fluid in each of the pipes 5 and 10 can be estimated, each temperature sensor for detecting the temperature of the working fluid in each of the pipes 5 and 10 is newly provided. Since it is not necessary, the structure is not complicated, and an increase in manufacturing cost can be suppressed.
In addition, according to the first embodiment, since the threshold value corresponding to the estimated temperature of the working fluid is set, it is possible to improve the determination accuracy as to whether or not there is a leak as compared with the conventional technique in which the threshold value is constant. And the reliability of the suspension device can be improved.

Note that the first embodiment is not limited to the above-described embodiment, and may be configured as follows, for example.
In the first embodiment, the relative speed of the vehicle height is calculated by differentiating the calculation result of the relative displacement of the vehicle height, but the relative speed of the vehicle height is calculated based on the behavior on the spring obtained from the vehicle information. can do.
In the first embodiment, the calculation result of the relative speed of the vehicle height is subjected to a moving average process. However, the moving average process can be replaced with a process that passes a low-pass filter having a long time constant.

  A second embodiment of the present invention will be described. In the second embodiment, the basic structure shown in FIG. 1, the main flow of the control device 16 shown in FIG. 2, and the control flow of the on-off valves 7 and 12 shown in FIG. 3 are the same as those of the first embodiment. And the fail determination process flow shown in FIG. 4 is different. In the second embodiment, the same name and reference numeral are assigned to the same or corresponding components as those in the first embodiment, and duplicate descriptions are omitted. Therefore, only the failure determination process flow will be described.

  FIG. 7 shows a fail determination process flow of the control device 16 in the suspension device of the second embodiment. When the fail determination processing flow is called in the control flow of the on-off valves 7 and 12 shown in FIG. 3 (step 50), the reference vehicle height data is subtracted from the vehicle height data obtained from the vehicle information, and the relative displacement of the vehicle height. Is calculated (step 51). Next, the calculation result of the relative displacement of the vehicle height is processed, and it is determined based on the calculation processing result whether or not the road surface is a bad road (step 52). Here, when it is determined that the road surface is a bad road (YES in step 52), the temperature rise flag of the working fluid in each of the pipes 5 and 10 is set (step 53). If it is determined in step 52 that the road surface is not a bad road (NO in step 52), the working fluid temperature rise flag is cleared (step 54).

  Then, the temperature rise flag of the working fluid is counted, and the temperature change amount of the working fluid in the pipes 5 and 10 is estimated based on the count number of the temperature rise flag within the specified time (step 55). The temperature change amount of the working fluid is estimated based on the table represented by the map of FIG. 6 stored in the storage area of the control device 16. Further, the estimated temperature change amount of the working fluid and the outside air temperature data obtained from the vehicle information are processed to estimate the temperature of the working fluid (step 56). Next, the estimation result of the temperature of the working fluid is calculated and the system pressure is estimated (step 57). Next, the actually measured system pressure detected by the pressure sensors 9, 14 is subtracted from the estimated system pressure (step 58).

Then, the differential pressure between the estimated system pressure and the actually measured system pressure is compared with the threshold value at the estimated temperature of the working fluid obtained in step 56 (step 59). When the differential pressure is equal to or less than the threshold value (YES in step 59) ), The fail flag is cleared, that is, it is determined that there is no leakage in each of the pipes 5 and 10 (step 60). When the differential pressure is larger than the threshold value in step 59 (NO in step 59), it is determined that the fail flag is set, that is, there is a leak in the first pipe 5 or the second pipe 10 (step 61). ). Here, steps 55 and 56 are fluid temperature estimating means, step 57 is a fluid pressure estimating means. Steps 58 to 61 are determination means. The threshold value in step 59 is set based on a table represented by a map in FIG. 5 stored in the storage area of the control device 16.

  According to the second embodiment, the same effect as that of the first embodiment can be obtained, and in particular, the fail detection accuracy on a rough road where a lot of pitches can be increased.

A third embodiment of the present invention will be described with reference to FIG. In addition, the same name and code | symbol are provided to the structure which is the same as that of 1st Embodiment, or corresponds.
In the suspension device of the third embodiment, the upper chamber of the front hydraulic cylinder 21 provided between the front wheel and the front stabilizer, and the rear provided between the rear wheel and the rear stabilizer. Flow of the working fluid between the first pipe 5 that allows the working fluid to flow between the upper chamber of the fluid pressure cylinder 22 and the lower chamber of the front fluid pressure cylinder 21 and the lower chamber of the rear fluid pressure cylinder 22. Second pipe 10 to be allowed. The first pipe 5 includes a damping valve 6, an on-off valve 7, a relief valve 8, and a pressure sensor 9 (first pressure measuring means), and is connected to a temperature compensating accumulator 15. The second pipe 10 includes a damping valve 11, an on-off valve 12, a relief valve 13, and a pressure sensor 14 (second pressure measuring means), and is connected to a temperature compensating accumulator 15.

The suspension device includes vehicle information such as vehicle height, longitudinal acceleration, lateral acceleration, vehicle speed, steering steering angle, steering steering angular velocity, engine speed, brake ON / OFF, throttle opening, outside air temperature, and pressure sensor 9, 14 includes a control device 16 including a microcomputer that controls the on-off valves 7 and 12 based on the pressure of the working fluid in the pipes 5 and 10 detected by the pipe 14. Incidentally, out vehicle height of the vehicle information is obtained from the detection result of the vehicle height detecting sensor.

  In the suspension device of the third embodiment, the control device 16 that controls the on-off valves 7 and 12 based on the vehicle information and the pressure of the working fluid in the pipes 5 and 10 detected by the pressure sensors 9 and 14. Since the control flow is the same as the control flow of the control device 16 in the suspension device of the first embodiment described above shown in FIGS. 2 to 4, detailed description thereof is omitted.

  According to the third embodiment, the same effect as that of the first embodiment can be obtained.

Note that the third embodiment is not limited to the above-described embodiment, and may be configured as follows, for example.
The fail determination processing flow in the suspension device control device 16 of the second embodiment shown in FIG. 7 can also be applied to the failure determination processing flow in the suspension device control device 16 of the third embodiment. As a result, it is possible to improve the fail detection accuracy on a rough road where a lot of pitches occur.

It is explanatory drawing which shows schematic structure of 1st Embodiment. It is a figure which shows the main flow in the control apparatus of the suspension apparatus of 1st Embodiment. It is a figure which shows the control flow of the on-off valve in the control apparatus of the suspension apparatus of 1st Embodiment. It is a figure which shows the failure determination flow in the control apparatus of the suspension apparatus of 1st Embodiment. It is a table of the threshold value set in the failure determination flow of the control apparatus of the suspension device of the first embodiment. It is a table which shows the relationship between the number of failure flags and the temperature change amount of a working fluid in the failure determination flow of the control apparatus of the suspension apparatus of 2nd Embodiment. It is a figure which shows the failure determination flow in the control apparatus of the suspension apparatus of 2nd Embodiment. It is explanatory drawing which shows schematic structure of 3rd Embodiment.

Explanation of symbols

1-2 1st fluid pressure cylinder, 3-4 2nd fluid pressure cylinder, 5 1st piping, 9 Pressure sensor (1st pressure measurement means), 10 2nd piping, 14 Pressure sensor (2nd pressure measurement means), 16 Control device

Claims (2)

At least one first hydraulic cylinder provided between the vehicle body and the left wheel;
At least one second hydraulic cylinder provided between the vehicle body and the right wheel;
A first pipe that allows a working fluid to flow between the upper chamber of the first fluid pressure cylinder and the lower chamber of the second fluid pressure cylinder;
A second pipe that allows the working fluid to flow between the upper chamber of the second fluid pressure cylinder and the lower chamber of the first fluid pressure cylinder;
First pressure measuring means for measuring the pressure of the working fluid inside the first pipe;
Second pressure measuring means for measuring the pressure of the working fluid inside the second pipe;
In a suspension device having
The relative speed of the vehicle height is calculated from the vehicle height data obtained from the vehicle information, and the temperature change amount of the working fluid in each pipe is calculated based on the average relative speed of the vehicle height obtained by averaging the relative speeds. Fluid temperature estimation means for estimating and estimating the temperature of the working fluid in each pipe based on each estimation result and outside air temperature;
Fluid pressure estimating means for estimating the pressure of the working fluid in each pipe based on each estimation result of the fluid temperature estimating means;
A difference between each estimated result of the fluid pressure estimating means and each measured result of the first and second pressure measuring means is calculated, and whether there is leakage of the working fluid in each pipe based on each calculated result. Determination means for determining;
A suspension device comprising: A forward fluid pressure cylinder provided between the front wheel and the front stabilizer;
A rear fluid pressure cylinder provided between the one rear wheel and the rear stabilizer;
A first pipe that allows a working fluid to flow between the upper chamber of the front fluid pressure cylinder and the lower chamber of the rear fluid pressure cylinder;
A second pipe that allows the working fluid to flow between an upper chamber of the rear fluid pressure cylinder and a lower chamber of the front fluid pressure cylinder;
First pressure measuring means for measuring the pressure of the working fluid inside the first pipe;
Second pressure measuring means for measuring the pressure of the working fluid inside the second pipe;
In a suspension device having
From the vehicle height data obtained from the vehicle information, the relative speed of the vehicle height is calculated, the calculation result of the relative speed is calculated, and based on the result of determining whether the road surface is a bad road based on the calculation processing result, Fluid temperature estimation means for estimating a temperature change amount of the working fluid in the pipe and estimating the temperature of the working fluid in the pipe based on each estimation result and the outside air temperature;
Fluid pressure estimating means for estimating the pressure of the working fluid in each pipe based on each estimation result of the fluid temperature estimating means;
Judgment that calculates the difference between each estimation result of the fluid pressure estimation means and each measurement result of the first and second pressure measurement means, and determines whether or not there is leakage of the working fluid based on each calculation result Means,
A suspension device comprising:

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