JPH0212764B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tire internal pressure management device for a rail vehicle such as a guide rail car or a monorail using pneumatic tires.

[Conventional technology]

In the above-mentioned types of vehicles, it is necessary to detect and deal with tire air leaks as early as possible in order to maintain safe driving and to prevent shortening of tire life. The method for detecting a decrease in tire internal pressure is as follows:
Two methods are known: one that detects the pressure directly by attaching a pressure switch or the like to the wheel itself, and the other that uses ground equipment to detect the phenomenon that occurs when a tire has a reduced internal pressure when a vehicle stops or passes over it.
Among these known methods, the ground method has a much smaller total number of detectors than installing a detector on each tire, and is much more advantageous in terms of equipment costs and maintenance management of the detection device. Compared to methods that detect internal pressure, there is a problem in that it is difficult to increase the sensitivity and accuracy of detection.

[Purpose of the invention]

The present invention was developed with this point in mind, and it is not only capable of detecting an abnormal decrease in tire internal pressure, but also has a high sensitivity that can detect even the slightest decrease in internal pressure, making it possible to manage tire internal pressure. The purpose of this invention is to obtain a ground-type tire internal pressure management device.

Another object of the present invention is to enable tire internal pressure management in response to the passage of multiple types of vehicles with significantly different tire sizes and tire loads.

[Effect]

Examples of the ground contact characteristics of pneumatic tires are shown in the graphs in Figures 1 and 2. The vertical axis is the ground contact pressure expressed as the load per unit area, the horizontal axis is the ground contact length, and the zero point is the ground contact. is the center of FIG. 1 shows an empty vehicle state with the minimum ground contact length. 9 which is the normal internal pressure
Diagram 1 shows the case of Kg/cm ² , and the internal pressure is 1/2, 4.5Kg/cm ²
The line diagram for 2.25Kg/cm 2 is 2, and the line diagram for 1/4 2.25Kg/cm ² is 3.
Figure 2 shows the tire load at maximum load, which is 1.5 times that of an empty car, and the normal internal pressure is 1' and 1/2 the internal pressure as in Figure 1.
2' and 1/4 internal pressure are shown at 3'. Figures 1 and 2
Comparing the figures, as seen in 1:1', 2:2', and 3:3', as the tire load increases, the ground contact pressure increases only slightly; regardless of the tire load, the ground contact pressure of the tire It can be said that it is almost proportional to the internal pressure. A dotted line 4 is a curve showing a substantially inversely proportional relationship. The area enclosed in each diagram represents the magnitude of the tire load, and the area remains constant even if the internal pressure changes. As the load increases, the ground contact length increases and the enclosed area increases. This means that the dynamic load while the vehicle is running increases or decreases the length of contact with the ground, causing almost no variation in the pressure of the ground contact. This point makes it possible to improve the sensitivity, which is a feature of the present invention. In the known internal pressure drop detection method that compares contact lengths, the contact length variation due to dynamic load changes that occur between the left and right tires is taken into account.
A ~30% change in left/right contact length ratio must be considered normal, and a 20-30% drop in internal pressure cannot be detected. In the present invention, the standard value for comparison judgment is set to 8.5 kg/cm ² against the normal internal pressure of 9 kg/cm ² , which is sufficient to avoid false detection due to characteristic errors due to individual tire differences.
It can be done to a certain extent.

With the above in mind, a specific method for detecting ground contact pressure is to install a load cell on the running surface of the tire, and to obtain the load per unit area, which is the ground contact pressure, the foot surface of the load cell is sufficiently smaller than the ground contact area of the tire. shall be. The load applied by the tire is measured by the load cell, and ground contact pressure can be obtained by dividing the load by the area of the foot surface. Ground contact pressure can be converted into tire internal pressure from the ground contact characteristics of the tire that have been determined in advance. The gist of the present invention is that the device is constructed based on this principle.

The present invention provides a load cell that is installed on the rolling surface of a pneumatic tire on a track for a rail vehicle having pneumatic tires and has a tread surface whose length in the vehicle traveling direction is shorter than the ground contact length of a normal tire, and the tread surface. It consists of an electrical device that has a function to measure the vertical load applied to the tire surface each time the pneumatic tire transfers the surface, a function to compare and judge this measured value with a reference value, and a function to display the results. This is a means to solve problems.

〔Example〕

As a publicly known example of using a ground detecting element with a length sufficiently shorter than the ground contact length, the applicant has proposed Japanese Patent Application Laid-open No. 54-120102 "Method and device for detecting decrease in tire internal pressure in a track vehicle having pneumatic tires", but the detecting element has a switch function that only detects when the tires are in contact, and the operating time of the switch is compared between the left and right tires, that is, the contact length is compared to detect a drop in internal pressure, which is enough to maintain safe driving. The aim was to obtain a sensitivity level of 1, and thereby simplify the structure.

In contrast, the present invention has the sensitivity to detect even the slightest drop in internal pressure, and is also capable of recording the internal pressure status of all tires, making it adaptable to tire internal pressure management. Furthermore, since the present invention is an absolute value detection method and not a left and right tire comparison method, the third
Even in the single-wheel monorail shown in the cross-sectional view,
Even in a guide railcar with pneumatic running wheels on the left and right sides shown in the cross section of Fig. 4, the internal pressure can be detected even when the internal pressure of both the left and right wheels decreases, and it is also possible to detect the internal pressure of the guide wheels, where the load fluctuates frequently. can.

FIG. 3 shows an embodiment of the present invention in a suspended monorail, in which the pneumatic tire running wheel 5 is a single wheel, and the load ratio of the left and right tires is detected on the tire rolling surface of the running track 6, as in the case of a double wheel. Since this is not possible, the load cell 7, which has a small foot surface area, detects the ground contact pressure and obtains the tire internal pressure. 8 is a guide wheel of a pneumatic tire, and 9 is a load cell with a small foot surface area for detecting the ground contact pressure of the guide wheel, and the present invention is also applied to the guide wheel. 10 is a frame of the traveling device, and 11 is a vehicle body.

FIG. 4 shows another embodiment of the invention in a guide rail car with left and right running wheels of pneumatic tires. A load cell 13 for the running wheel 12 is buried in the running path 14, and a guide wheel 15 of the pneumatic tire
A load cell 16 for the tire is embedded in the tire rolling surface of the guide rail 17. 18 is the axle of the running wheel;
19 is a beam that supports the guide wheels, and 20 is a vehicle body.

FIG. 5 is an explanatory diagram showing the relationship between the load cell and the contact surface of the tire in the present invention, and shows a vehicle where the left-right distance between the wheels is L ₁ and the tire contact width is W ₁ , and a vehicle where the left-right distance between the wheels is L ₂ and the tire contact width is W 1. When vehicles with a ground contact width of W ₂ run on the same track, the area of the foot surface of the load cell 13 is small, so it is within the area of both the contact surface A of the tire of the former vehicle and the contact surface B of the tire of the latter vehicle. The load cell 13 is also included, and surface pressure can be detected. Furthermore, when the width of the load cell is smaller than the tire tread width, it is advantageous to accurately grasp the ground pressure because the denominator of the formula [load cell load/foot surface area] is constant. Tire contact width
Even if there is a large difference between W ₁ and W ₂ , the ground pressure of any vehicle can be accurately detected.

Figure 6 is an explanatory diagram showing the relationship between the load _cell and the tire contact surface when using a load cell with a foot surface wider than the tire contact width. is W ₃ , the left and right distance between the wheels is L ₄ , and the tire contact surface D is
When W ₄ vehicles run on the same track and the tire contact widths W ₃ and W ₄ are the same or almost equal, the tire contact width of both tires is set to be wider than the tire contact width by making the foot surface of the load cell 21 wider than the tire contact width. By making it included in the foot surface, the ground pressure can be detected. In other words, the area that is the denominator of the ground pressure calculation formula is obtained by multiplying W ₃ or W ₄ by the length l of the load cell foot surface, so W ₃ = W ₄ or W ₃ ≒
This is because if W ₄ , the area will be constant or almost constant. When using such a load cell with a wide lateral surface, the load value, which is a numerator, is large, so the error factor in measurement is reduced. This structure is advantageous when only one type of vehicle is passing through.

Since the present invention is a method of measuring ground contact pressure which is approximately proportional to the tire internal pressure, it is unrelated to the magnitude of the load. Therefore, even if different types of vehicles have significantly different tire loads, there will be no problem in detection as long as the tire internal pressures are approximately the same.

When vehicles using pneumatic tires with different standard internal pressures run on the same track, it is necessary to change the reference value for comparison. For this purpose, information regarding a reference value according to the type of vehicle passing on the surface of the load cell of the tire internal pressure management device is received from the outside, and the electric device of the tire internal pressure management device can make a comparative judgment and perform correct display. Another method is to calculate the average value of all the tire measurements of one train that has passed on the premise that the proportion of tires that cause abnormalities in all tires is very small, and then subtract a certain value from that value or calculate the average value. Practical tire internal pressure management is possible by multiplying the coefficient by the reference value for comparison.

In order to manage the tire internal pressure automatically and in detail, a plurality of reference values for comparison and judgment can be set in the electric device, and a plurality of levels of display can be displayed depending on the degree of decrease in the internal pressure. For example, term internal pressure 9
Kg/ ^cm2 , the standard values are 8.5, 7, and 5Kg/, respectively.
Set to cm ² and display ``slight'', ``medium'', and ``large''. Among these, when the display shows "large", the train should be immediately commanded to stop or run at low speed. Whether this command should be given manually or whether the train should be automatically controlled should be decided based on the relationship with other systems other than the tire pressure management device. If "medium" is displayed, the decision to continue operation should be made early. The display of "slight amount" allows for detailed management as shown in the example, such as instructing vehicle maintenance personnel to replenish air.

By providing the tire internal pressure management device with a recording function or a function of transmitting measured values, data on tire internal pressure measured values can be easily recorded. For this recording, if the train operation management is automated by using a computer, etc., it is easy to record the vehicle number, date and time, etc. at the same time. When linking with a traffic management system, the measured values can be transmitted to the traffic management system and transferred to the computer of the traffic management system, which has a judgment function that is a shared function of the tire internal pressure management device.

In order to maintain safe running, the device of the present invention should be installed at about one location every few meters on a commercial main line, but its function may be limited to a display that allows judgment to be made to maintain safe running. By providing a pair of recording functions or a pair of indicators based on multiple reference values at one point on the main track where all vehicles must pass, or at the entrance/exit line, it is possible to detect air leaks that are within the safe range for driving but are leakier than normal. If you drive for a long time, you will be able to tell that the lifespan of your tires will be shortened.

〔Effect of the invention〕

As described in detail above, the tire internal pressure management device of the present invention uses a load cell that has a foot surface sufficiently smaller than the tire's contact length to detect the tire contact pressure and obtain the tire internal pressure to control the tire movement. High sensitivity can be obtained without being affected by natural load fluctuations, and sufficient data can be obtained to manage tire internal pressure and correct judgment can be made. Furthermore, it is useful because it can handle the running of different vehicles and has the possibility of automating the operation processing after internal pressure is detected by linking it with systems such as operation management.

[Brief explanation of drawings]

Figures 1 and 2 are graphs showing the ground contact characteristics of pneumatic tires when empty and fully loaded, respectively. Figure 3 is a partially sectional front view showing one embodiment of the present invention. Figure 4 is a diagram showing another embodiment. FIGS. 5 and 6 are partially sectional front views showing an example, and are explanatory diagrams showing the relationship between a load cell embedded in a running path and the ground contact surfaces of pneumatic tires having different left and right spacing between the wheels. In the figure, 5, 12... running wheels. 6...Travel trajectory.
7, 9, 13, 16, 21...Load cell. 8,
15... Guide wheel. 10...Frame. 11...Car body. 14...Running route. 17...Guidance track. 18...
…Wheel. 19...Acupuncture. 20...Car body. A, B,
C, D...Pneumatic tire contact surface. L ₁ , L ₂ , L ₃ ,
L ₄ ... Left and right distance between wheels. W ₁ , W ₂ , W ₃ , W ₄ ...
Tire contact width. l...Length of the load cell's bottom surface.

Claims (1)

[Scope of Claims] 1. A load cell having a foot surface whose length in the vehicle traveling direction is shorter than the ground contact length of a normal tire, which is installed on the rolling surface of a pneumatic tire on a track for a rail vehicle having pneumatic tires; An electric device that has a function of measuring the vertical load applied to the tire's tire surface each time a pneumatic tire rolls on the tire's tire surface, a function of comparing the measured value with a reference value, and a function of displaying the result. A tire internal pressure management device for a track vehicle having pneumatic tires, characterized by comprising: 2. A tire internal pressure management device for a rail vehicle having pneumatic tires according to claim 1, wherein the load cell is formed to have a tread surface having a width narrower than the ground contact width of the pneumatic tires. 3. A tire internal pressure management device for a rail vehicle having pneumatic tires according to claim 1, wherein the load cell is formed to have a tread surface wider than the ground contact width of the pneumatic tires. 4. A pneumatic tire according to claim 1, characterized in that an electric device is provided with a function of recording the measured values of each tire that has passed through the vehicle or a function of transmitting the measured values to an external recording device. Tire internal pressure management device for track vehicles. 5. The electric device according to claim 1, which has a plurality of reference values in the electrical device, and has a function of comparing the measured value with the plurality of reference values and displaying the results for each reference value. Tire internal pressure management device in a track vehicle with pneumatic tires. 6. The tire internal pressure management device for a track vehicle having pneumatic tires as set forth in claim 1, characterized by having a function of making a comparative judgment based on reference value information provided from the outside and corresponding to the vehicle type. 7. It is characterized by having a function of making a comparative judgment using a value obtained by subtracting a certain value from the average value of the measured values of each tire in one train, or a value obtained by multiplying the said average value by a certain coefficient smaller than 1 as a reference value. A tire internal pressure management device for a rail vehicle having pneumatic tires according to claim 1.