Internal pressure adjustment method and internal pressure adjustment device

Abstract

To regulate the internal pressure of a tire which cannot be regulated within a predetermined period so that the internal pressure of the tire enters a prescribed range until a next chance of internal pressure regulation.SOLUTION: A controller (1) performs control to regulate the internal pressure of a tire (4) by the use of a result of calculation made so that the internal pressure of the tire (4) in an operation scheduled period enters a predetermined range from a temperature zone of temperature of the tire (4) varying with a predicted temperature in the operation scheduled period and an operation pattern of a vehicle mounted with the tire (4).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an internal pressure adjusting method and an internal pressure adjusting device. [Background technology]

[0002] For air-filled tires, the appropriate internal pressure is specified in advance to ensure the tire performs as designed, and when inspecting the tire, it is required to adjust the internal pressure so that it falls within the specified range.

[0003] For example, Patent Document 1 discloses a method and device for adjusting the internal pressure of aircraft tires. Patent Document 2 discloses a method for adjusting the internal pressure of tires by taking into account changes in outside air temperature and loss of air pressure due to leakage. Patent Document 3 discloses a method for measuring the outside air temperature and determining whether or not to check the tire air pressure by using the measured outside air temperature and the outside air temperature at the time of adjusting the internal pressure of the tires. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-193225 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-276570 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-22552 Summary of the Invention [Problem to be solved by the invention]

[0005] Depending on the tire, there may be situations where the internal pressure can only be adjusted during a predetermined period before winter arrives, due to the vehicle operating environment, such as surrounding roads being closed off by snow in winter.

[0006] For vehicles operating under these conditions, it is important to adjust the tire pressure before winter arrives so that the tire pressure remains within the specified range until the next tire pressure adjustment, even if the outside temperature changes.

[0007] However, up until now, tire workers have relied on experience and intuition to adjust tire pressure so that it would remain within the specified range until the next adjustment. Therefore, if the outside temperature becomes lower or higher than expected, the tire pressure may exceed the specified range.

[0008] The present disclosure aims to provide an internal pressure adjustment method and an internal pressure adjustment device that can adjust the internal pressure of a tire that can only have its internal pressure adjusted within a predetermined period of time so that the internal pressure of the tire remains within a predetermined range until the next opportunity for internal pressure adjustment. [Means for solving the problem]

[0009] In order to achieve the above object, the first aspect is The internal pressure of the tire is adjusted using a result calculated from the predicted temperature for a future use period in which the vehicle equipped with the tire is scheduled to be used and the temperature range of the tire that varies depending on the operation pattern of the vehicle, so that the internal pressure of the tire during the use period falls within a predetermined specified range recommended for the tire. This is a method for adjusting internal pressure.

[0010] A second aspect is the internal pressure adjusting method of the first aspect, the tire temperature zone is a temperature zone for each operating state of the vehicle, which is expressed by a lower limit relative temperature and an upper limit relative temperature with respect to a reference temperature that changes daily; calculate an internal tire pressure at an air temperature of a location where the internal tire pressure adjustment is performed, such that the internal tire pressure during the usage period falls within the specified range even if the temperature of the tire changes from a first temperature corresponding to a lower limit relative temperature of the temperature range having the lowest lower limit relative temperature to a second temperature corresponding to an upper limit relative temperature of the temperature range having the highest upper limit relative temperature; The internal pressure of the tire is adjusted so as to approach the calculated internal pressure.

[0011] A third aspect is the internal pressure adjusting method of the second aspect, If the average value of the reference temperature during the usage period is lower than the reference temperature on the day on which the internal pressure of the tire is adjusted, the internal pressure of the tire of the vehicle is adjusted so that the internal pressure of the tire at the first temperature is the lower limit of the specified range, and if the average value of the reference temperature during the usage period is higher than the reference temperature on the day on which the internal pressure of the tire is adjusted, the internal pressure of the tire of the vehicle is adjusted so that the internal pressure of the tire at the second temperature is the upper limit of the specified range.

[0012] A fourth aspect is the internal pressure adjusting method of the second or third aspect, The reference temperature is the lowest temperature during the usage period included in the predicted temperature.

[0013] A fifth aspect is the internal pressure adjusting method according to any one of the first to fourth aspects, The temperature range of the tire is set using either a temperature obtained from a sensor attached to the tire whose internal pressure is to be adjusted and measuring the temperature of the tire, a temperature of the tire obtained from a simulation result of driving the vehicle in accordance with the vehicle's operating pattern, or a temperature obtained from a tire of the same type as the tire attached to another vehicle that operates in the same operating pattern as the vehicle on which the tire is attached.

[0014] A sixth aspect is the internal pressure adjusting method according to any one of the first to fifth aspects, The predicted temperature is estimated using past temperatures for the same period as the utilization period.

[0015] A seventh aspect is the internal pressure adjusting method according to any one of the first to sixth aspects, The tire whose internal pressure is to be adjusted is a tire for an industrial vehicle.

[0016] The eighth aspect is an acquisition unit that acquires a predicted temperature for a future use period in which a vehicle equipped with the tire is scheduled to be used and a temperature range of the tire that changes depending on an operation pattern of the vehicle; a control unit that performs control to adjust the internal pressure of the tire using a result calculated from the predicted air temperature and the temperature zone of the tire acquired by the acquisition unit so that the internal pressure of the tire during the usage period falls within a predetermined specified range recommended for the tire; and It is an internal pressure adjusting device equipped with. [Effects of the Invention]

[0017] According to the present disclosure, for tires whose internal pressure can only be adjusted within a predetermined period, the internal pressure of the tire can be adjusted so that the internal pressure of the tire falls within a predetermined range until the next opportunity for internal pressure adjustment. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a tire internal pressure adjustment system. [Figure 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a control device. [Figure 3] FIG. 10 is a diagram showing an example of measurement results showing the relationship between tire temperature and the lowest outside air temperature. [Figure 4] FIG. 10 is a diagram showing an example of tire temperature information based on a vehicle driving pattern. [Figure 5] FIG. 2 is a diagram illustrating an example of the configuration of a main part of an electrical system in the control device. [Figure 6]4 is a flowchart showing an example of the flow of a control process executed by the control device. [Figure 7] FIG. 4 is a diagram showing an example of tire temperature information. [Figure 8] FIG. 4 is a diagram showing an example of a tire temperature-internal pressure relationship. [Figure 9] FIG. 4 is a diagram showing an example of the relationship between tire temperature and internal pressure when the internal pressure of the tire at a first temperature is set to the lower limit value of a specified range. [Figure 10] FIG. 10 is a diagram showing an example of the relationship between tire temperature and internal pressure when the internal pressure of the tire at a second temperature is set to the upper limit value of a specified range. [Figure 11] FIG. 10 is a diagram showing another example of the configuration of the tire internal pressure adjustment system. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present embodiment will be described below with reference to the drawings. Note that the same components and processes are given the same reference numerals throughout the drawings, and redundant description will be omitted.

[0020] 1 is a diagram showing an example of the configuration of an internal pressure adjustment system for a tire 4. As shown in FIG. 1, the internal pressure adjustment system is a system including a control device 1, a temperature sensor 2, and an internal pressure adjustment device 3.

[0021] The temperature sensor 2 is a sensor that measures the air temperature at the location where air is filled into the tire 4, the internal pressure of which is to be adjusted. There are no restrictions on the type of temperature sensor 2 as long as it can measure the air temperature, and for example, a temperature sensor 2 that uses a thermocouple or a thermistor can be used. Hereinafter, the air temperature at the location where the internal pressure of the tire 4 is adjusted will be referred to as the "ambient temperature."

[0022] The air refers to a gas filled in the tire 4, and may be, for example, air, nitrogen gas, or a mixture of air and nitrogen gas.

[0023] When the control device 1 acquires the ambient temperature from the temperature sensor 2, it calculates the internal pressure (referred to as the "target internal pressure") at the ambient temperature so that the internal pressure of the tire 4 falls within a predetermined range for the tire 4 over the period from the current internal pressure adjustment to the next internal pressure adjustment, and notifies the internal pressure adjustment device 3 of this internal pressure.

[0024] When the internal pressure adjusting device 3 receives the target internal pressure from the control device 1, it fills the tire 4 with air so that the internal pressure of the tire 4 approaches the notified target internal pressure.

[0025] Although there are no restrictions on the type of tire 4 whose internal pressure is to be adjusted by the internal pressure adjustment system, as an example, this embodiment will describe an example of adjusting the internal pressure of a tire 4 of an industrial vehicle whose internal pressure can only be adjusted during a predetermined period, such as a period before delivery to a construction site or a period after a road closure due to snow on the road to the construction site is lifted, such as tires 4 mounted on pile drivers and backhoes operating at construction sites in the mountains, mining machines that excavate ore, rocks, etc. in mines and quarries, and trucks that transport mined ore, rocks, etc. Note that, unless otherwise specified, the tire 4 in this embodiment refers to the tire 4 whose internal pressure is to be adjusted by the internal pressure adjustment system.

[0026] 2 is a diagram showing an example of the functional configuration of the control device 1. The control device 1 includes functional units, such as a sensor input unit 11, an information acquisition unit 12, an adjustment unit 13, and a communication unit 14, as well as databases, such as an air temperature DB 15 and a tire information DB 16.

[0027] Here, "DB" is an abbreviation for "Database," which is a data management mechanism that stores specified information so that it can be read later. Therefore, it is not necessary to use a commercially available relational database or the like to build the temperature DB 15 and tire information DB 16; the file system of the operating system implemented in the control device 1 may be used.

[0028] First, the data stored in the temperature DB 15 and the tire information DB 16 will be described.

[0029] The temperature DB 15 stores temperature forecast information, which is the predicted temperature for a future usage period (referred to as a "planned operation period") during which an industrial vehicle (hereinafter simply referred to as a "vehicle") equipped with the tire 4 is scheduled to be used. For example, in the case where the internal pressure of a tire 4 mounted on a transport vehicle scheduled to be used in a mine during the winter is adjusted in advance during the fall, the temperature DB 15 stores the predicted temperature information for the winter period as of the fall.

[0030] For example, temperature forecast information published by the Japan Meteorological Agency is used as the temperature forecast information stored in the temperature DB 15. The temperature forecast information published by the Japan Meteorological Agency includes the predicted minimum temperature and the predicted maximum temperature during the planned operation period (winter period in this case). Therefore, the temperature DB 15 stores at least the predicted minimum temperature and the predicted maximum temperature during the planned operation period.

[0031] On the other hand, the tire information DB 16 stores temperature information that indicates the temperature range of the temperature of the tire 4 that changes depending on the driving pattern of the vehicle.

[0032] For example, transport vehicles used in mines, which are an example of vehicles, operate from morning until night when it is still light outside, and stop operating from night until before sunrise, repeating this operation every day, while also having periods where the vehicle is stopped for more than a day.

[0033] Hereinafter, the period during which the vehicle is in operation every day will be referred to as the "steady operation period," and the period during which the vehicle is stopped for one day or more will be referred to as the "long-term shutdown period." Furthermore, the transition period from the long-term shutdown period to the steady operation period will be referred to as the "start-up period."

[0034] The inventors measured the average temperature of the air inside the tires 4 (referred to as "tire temperature") using a sensor such as a tire pressure monitoring system (TPMS) attached to the tires 4 of a vehicle having such a driving pattern.

[0035] Figure 3 shows an example of the measurement results of the daily tire temperature fluctuation range of a vehicle operating according to a travel pattern and the daily minimum outside air temperature (referred to as "minimum temperature") at the site where the vehicle is operating, measured from January 2021 to October 2021. The horizontal axis in Figure 3 represents the measurement date, and the vertical axis represents the temperature [°C].

[0036] In addition, each point 8 in Figure 3 represents the minimum air temperature for each day, and each point 9 represents the vehicle's tire temperature. The vehicle's tire temperature was measured multiple times during the day, and the arrangement of points 9 along the vertical axis indicates the range of daily tire temperature fluctuations. In Figure 3, periods D1, D2, and D3 represent long-term shutdown periods.

[0037] On the other hand, line 6A-1 represents the regression line for the distribution of minimum temperatures from January 2021 to early August 2021, and line 6A-2 represents the regression line for the distribution of minimum temperatures from early August 2021 to the end of August 2021. Also, line 6B-1 represents the regression line for the distribution of the lower limit tire temperature during the steady operation period from January 2021 to early August 2021, and line 6B-2 represents the regression line for the distribution of the lower limit tire temperature during the steady operation period from early August 2021 to the end of August 2021.

[0038] The measurement results shown in Figure 3 show that the tire temperature before the vehicle starts operating after a long shutdown period tends to drop to the minimum temperature, and that the lower limit of tire temperature during steady operation tends to be about 20°C higher than the minimum temperature. This indicates that the minimum temperature is the dominant factor affecting tire temperature among the daily temperatures.

[0039] It was also found that the tire temperature of a vehicle during normal operation is generally kept below the minimum temperature + 35°C, but can rise above the minimum temperature + 35°C when work is performed that is heavier than normal. Even when work is performed that is heavier than normal, the tire temperature of the vehicle never rose above the minimum temperature + 45°C.

[0040] Therefore, it can be seen that the tire temperature exhibits characteristic changes for each operating state in the vehicle driving pattern, and that the tire temperature in the vehicle driving pattern changes based on the minimum air temperature.

[0041] Hereafter, [minimum temperature + 35°C] will be referred to as the "standard upper relative temperature limit" for tire temperature during steady-state operation, and [minimum temperature + 45°C] will be referred to as the "high-load upper relative temperature limit."

[0042] FIG. 4 is a diagram showing an example of temperature information of the tire 4, which is a model of the tire temperature that changes depending on the vehicle operation pattern, based on the knowledge obtained from the measurement results shown in FIG.

[0043] As shown in Fig. 4, the temperature information of the tires 4 is divided into a plurality of temperature zones depending on the operating state of the vehicle in the driving pattern. Specifically, the temperature information of the tires 4 is expressed in three temperature zones: a long-term stop zone, a regular use zone, and a high temperature zone, which are divided by a lower limit relative temperature and an upper limit relative temperature to a reference temperature that changes daily. In this embodiment, the minimum air temperature is used as the reference temperature based on the knowledge obtained from the measurement results shown in Fig. 3.

[0044] The long-term stop range in the temperature information of tire 4 represents a temperature range from the lowest tire temperature limit during the long-term stop period to the lowest tire temperature limit during the normal operation period. Specifically, the long-term stop range in the temperature information of tire 4 represents a temperature range equal to or higher than [minimum temperature + 0°C] and lower than [minimum temperature + 20°C]. For ease of explanation, the lowest tire temperature limit in the temperature range of the long-term stop range, [minimum temperature + 0°C], may be referred to as the "lower limit relative temperature for neglect."

[0045] The normal range in the temperature information of tire 4 indicates a temperature range from the lower limit of the tire temperature during a normal operating period to the standard upper limit relative temperature. Specifically, the normal range in the temperature information of tire 4 indicates a temperature range of [minimum temperature + 20°C] or more and less than [minimum temperature + 35°C].

[0046] The high temperature range in the temperature information of tire 4 indicates a temperature range from the standard upper limit relative temperature to the high load upper limit relative temperature. Specifically, the high temperature range in the temperature information of tire 4 indicates a temperature range of [minimum temperature + 35°C] or more and less than [minimum temperature + 45°C].

[0047] In this way, the temperature information of the tire 4 is expressed as a relative temperature, which is a value relative to the minimum air temperature. Note that the lower limit value of the temperature range in the long-term stop range, i.e., the left lower limit relative temperature, is an example of the lower limit relative temperature of the lowest temperature range in the temperature information of the tire 4, and the upper limit value of the temperature range in the high-temperature range, i.e., the high-load upper limit relative temperature, is an example of the upper limit relative temperature of the highest temperature range in the temperature information of the tire 4. The upper and lower limit values ​​of each temperature range can be expressed as absolute values ​​once the minimum air temperature is determined.

[0048] Furthermore, since the temperature information of the tires 4 is expressed using the minimum temperature as a reference temperature, the temperature forecast information stored in the temperature DB 15 only needs to include at least the minimum temperature.

[0049] 2 acquires the ambient temperature from the temperature sensor 2, converts the acquired ambient temperature into a data format recognizable by the adjustment unit 13, and notifies the adjustment unit 13. For example, if the temperature sensor 2 outputs the ambient temperature using a continuous value such as a voltage value or a resistance value, the sensor input unit 11 performs A / D conversion to convert the ambient temperature into a discrete value before notifying the adjustment unit 13.

[0050] The information acquisition unit 12 acquires temperature forecast information for the planned operation period and temperature information of the tires 4 from the temperature DB 15 and the tire information DB 16, respectively, in accordance with instructions from the adjustment unit 13. Then, the information acquisition unit 12 notifies the adjustment unit 13 of the acquired temperature forecast information and temperature information of the tires 4. In other words, the information acquisition unit 12 functions as an interface between the temperature DB 15, the tire information DB 16, and the adjustment unit 13.

[0051] The adjustment unit 13 uses the temperature forecast information acquired from the temperature DB 15, the temperature information of the tire 4 acquired from the tire information DB 16, and the ambient temperature measured by the temperature sensor 2 to calculate the internal pressure of the tire 4 so that the internal pressure of the tire 4 falls within the recommended specified range during the planned operation period, i.e., the predicted temperature period represented by the temperature forecast information.

[0052] The specified range is the internal pressure of the tire 4 that is predetermined so that the tire 4 performs as designed, and is set for each tire 4. The specified range is expressed as a width, for example, not less than 700 kPa and not more than 960 kPa.

[0053] The adjustment unit 13 calculates the internal pressure of the tire 4 using Boyle's law. According to Boyle's law, when the volume is constant, the ratio of pressure to temperature, i.e., pressure / temperature, is constant. Therefore, the adjustment unit 13 calculates, as the target internal pressure, the internal pressure of the tire 4 under an ambient temperature environment such that the internal pressure of the tire 4 falls within a specified range even if the tire temperature changes from a temperature corresponding to the lower limit relative temperature for neglect (referred to as the "first temperature") to a temperature corresponding to the upper limit relative temperature for high load (referred to as the "second temperature") during the expected operation period. The adjustment unit 13 notifies the communication unit 14 of the calculated target internal pressure.

[0054] The communication unit 14 transmits the target internal pressure received from the adjustment unit 13 to the internal pressure adjustment device 3 through a communication line 5A connected to the internal pressure adjustment device 3. As long as the target internal pressure can be transmitted to the internal pressure adjustment device 3, there are no restrictions on the connection form of the communication line 5A, and the communication line 5A may be a wired line or a wireless line.

[0055] When the internal pressure adjusting device 3 receives the target internal pressure from the control device 1, it inflates the tire 4 with air so that the internal pressure of the tire 4 approaches the target internal pressure.

[0056] Therefore, the adjustment unit 13 of the control device 1 functions as a control unit that controls the internal pressure of the tire 4 via the internal pressure adjustment device 3. In addition, the sensor input unit 11 and the information acquisition unit 12 of the control device 1 function as an acquisition unit that acquires information used by the adjustment unit 13 to calculate the internal pressure of the tire 4.

[0057] Such a control device 1 is configured using, for example, a computer 20. FIG. 5 is a diagram showing an example of the configuration of the main parts of an electrical system in the control device 1 configured using the computer 20.

[0058] 2, a ROM (Read Only Memory) 22 that stores a control program that causes the computer 20 to function as the control device 1, a RAM (Random Access Memory) 23 that is used as a temporary work area for the CPU 21, a nonvolatile memory 24, and an input / output interface (I / O) 25. The CPU 21, ROM 22, RAM 23, nonvolatile memory 24, and I / O 25 are all connected to each other via a bus 26.

[0059] The nonvolatile memory 24 is an example of a storage device that maintains stored information even if the power supplied to the nonvolatile memory 24 is cut off, and is, for example, a semiconductor memory or a hard disk. Information that needs to be kept stored even if the power supply to the control device 1 is cut off, such as the temperature forecast information stored in the temperature DB 15 and the temperature information of the tires 4 stored in the tire information DB 16, is stored in the nonvolatile memory 24.

[0060] The nonvolatile memory 24 does not necessarily have to be built into the computer 20, but may be, for example, a portable storage device that can be attached to and detached from the computer 20.

[0061] To the I / O 25, for example, a temperature sensor 2, a communication unit 27, an input unit 28, and a display unit 29 are connected.

[0062] The communication unit 27 is connected to the communication line 5A and has a communication protocol for transmitting and receiving data to and from the internal pressure regulating device 3, which is also connected to the communication line 5A. The target internal pressure is transmitted from the control device 1 to the internal pressure regulating device 3 via the communication unit 27.

[0063] The input unit 28 is a device that receives instructions from the user and notifies the CPU 21 of the instructions, and includes, for example, at least one of a button, a touch panel, a mouse, a keyboard, and a pointing device.

[0064] The display unit 29 is an example of a display device that visually displays information processed by the CPU 21 (for example, the calculated target internal pressure), and includes, for example, a liquid crystal display or an organic EL (Electro Luminescence) display.

[0065] The sensors and units connected to the I / O 25 are not limited to the configuration shown in FIG. 5, and can be selected as needed.

[0066] Next, a control process executed by the control device 1 to adjust the internal pressure of the tire 4 to the target internal pressure will be described.

[0067] FIG. 6 is a flowchart showing an example of the flow of control processing executed by the CPU 21 of the control device 1 when an instruction to adjust the internal pressure of the tire 4 is received from the user via the input unit 28, for example.

[0068] A control program that defines the control processing is stored in advance, for example, in the ROM 22 of the control device 1. The CPU 21 of the control device 1 reads the control program stored in the ROM 22 and executes the control processing.

[0069] It is assumed that the specified range of the tire 4, the temperature prediction information, and the temperature information of the tire 4 are each stored in advance in the nonvolatile memory 24.

[0070] First, in step S10, the CPU 21 acquires from the nonvolatile memory 24 the temperature forecast information for the planned operation period of the vehicle on which the tire 4 is mounted, and stores it in the RAM 23.

[0071] In step S20, the CPU 21 acquires the temperature information of the tire 4 from the nonvolatile memory 24 and stores it in the RAM 23. FIG.

[0072] In step S30, the CPU 21 acquires the ambient temperature from the temperature sensor 2 and stores it in the RAM 23.

[0073] In step S40, the CPU 21 calculates the first temperature and the second temperature by adding the predicted minimum temperature included in the temperature prediction information acquired in step S10 to each of the left-standing lower limit relative temperature and the high-load upper limit relative temperature in the temperature information of the tire 4 acquired in step S20.

[0074] Then, the CPU 21 calculates the internal pressure of the tire 4 under the ambient temperature environment as the target internal pressure such that the internal pressure of the tire 4 at the first temperature and the internal pressure of the tire 4 at the second temperature are each within a specified range.

[0075] Specifically, if the ambient temperature is T0, the first temperature is T1, the second temperature is T2, the target internal pressure is P0, the lower limit of the specified range is P1, and the upper limit of the specified range is P2, the CPU 21 calculates the target internal pressure as an internal pressure that satisfies both equations (1) and (2).

[0076] (P1 / T1)≦(P0 / T0) (1) (P2 / T2)≧(P0 / T0) (2)

[0077] For example, if the predicted minimum temperature during the planned operation period is -20°C for the temperature information of tire 4 shown in Figure 7, the first temperature T1 will be -20°C (absolute temperature 253K) and the second temperature T2 will be 25°C (absolute temperature 298K).

[0078] In contrast, if the lower limit P1 of the specified range for tire 4 is 700 kPa, the upper limit P2 is 960 kPa, and the ambient temperature T0 is 27°C, then from equations (1) and (2), the target internal pressure P0 will be 830 kPa or higher and 966 kPa or lower. For example, if the target internal pressure for tire 4 is set to 926 kPa, which is within the range of 830 kPa or higher and 966 kPa or lower, the internal pressure of tire 4 at the first temperature will be 781 kPa and the internal pressure of tire 4 at the second temperature will be 920 kPa. Therefore, even if the tire temperature changes from -20°C to 25°C during the planned vehicle operation period, the internal pressure of tire 4 will fall within the specified range.

[0079] That is, even if the tire temperature changes in accordance with the driving pattern of the vehicle, the internal pressure of the tire 4 continues to remain within the specified range.

[0080] FIG. 8 is a diagram showing the relationship between the specified range of tire 4 shown in the above example and the internal pressure of tire 4 due to changes in tire temperature in accordance with the vehicle driving pattern (referred to as the "tire temperature-internal pressure relationship").

[0081] 6, after calculating the target internal pressure in step S40, in step S50, the CPU 21 transmits the target internal pressure calculated in step S40 to the internal pressure adjusting device 3 via the communication unit 27, and ends the control process. As a result, the internal pressure of the tire 4 is adjusted to the target internal pressure by the internal pressure adjusting device 3.

[0082] As described above, the internal pressure adjustment system according to this embodiment acquires temperature forecast information for the planned operation period and temperature information for the tires 4, and adjusts the internal pressure of the tires 4 so that the internal pressure of the tires 4 during the planned operation period falls within a specified range using the temperature forecast information and the temperature information for the tires 4. Therefore, even if circumstances prevent inspection of the tires 4 during the planned operation period, the internal pressure of the tires 4 is more likely to fall within the specified range over the future period compared to when an operator adjusts the internal pressure of the tires 4 based on experience and intuition.

[0083] 1, the control device 1 and the internal pressure adjustment device 3 are described as independent devices, but the control device 1 and the internal pressure adjustment device 3 may be integrated together. In other words, the control device 1 may be configured as a control unit for the internal pressure adjustment device 3. Although the present embodiment uses the minimum air temperature as the reference temperature, the maximum or average temperature of the site where the vehicle operates, such as a mine, may also be used as the reference temperature. In this case, the temperature information of the tire 4 may be set as information on a temperature range expressed as a relative temperature to the maximum or average temperature of the site where the vehicle operates, such as a mine.

[0084] Furthermore, in this embodiment, the temperature forecast information published by the Japan Meteorological Agency is used as the temperature forecast information, but the method for setting the temperature forecast information is not limited to this. For example, the control device 1 may acquire daily temperature data at a site where the vehicle operates, such as a mine, and estimate temperature forecast information for the planned operation period using past temperature data for the same period as the planned operation period. Specifically, the control device 1 may use the average value of the minimum daily temperatures for the past N years (N is a natural number) at the site where the vehicle operates for the same period as the planned operation period as the predicted minimum temperature in the temperature forecast information. Furthermore, the control device 1 may use the lowest minimum daily temperature for the past N years at the site where the vehicle operates for the same period as the planned operation period as the predicted minimum temperature in the temperature forecast information.

[0085] The predicted maximum temperature in the temperature forecast information is also estimated from past temperature data for the same period as the planned operation period using the same method as the predicted minimum temperature.

[0086] In this way, by estimating weather data such as the predicted minimum and maximum temperatures in the temperature forecast information from past weather data, local temperature forecast information limited to a specific area, such as the location where the vehicle is operating, can be obtained. By using local temperature forecast information, the accuracy of calculating the target internal pressure is improved compared to using temperature forecast information released by the Japan Meteorological Agency for each city, town, or village, for example. As a result, the internal pressure of the vehicle's tires 4 during the planned operation period is less likely to deviate from the specified range.

[0087] Furthermore, in this embodiment, the temperature information of the tire 4 is set using the temperature obtained from the TPMS attached to the tire 4 whose internal pressure is to be adjusted, but the method for setting the temperature information of the tire 4 is not limited to this. For example, the control device 1 may set the temperature information of the tire 4 using temperature information of the tire 4 obtained from the results of a simulation in which a computer is used to drive a vehicle along a driving pattern, or temperature information obtained from another tire of the same type as the tire 4 whose internal pressure is to be adjusted that is attached to another vehicle that operates according to the same driving pattern as the vehicle on which the tire 4 whose internal pressure is to be adjusted is attached.

[0088] As a result, even if the tire temperature cannot be obtained from the tire 4 whose internal pressure is to be adjusted, the temperature information of the tire 4 whose internal pressure is to be adjusted can be obtained.

[0089] <Modification of internal pressure adjustment> In step S40 of the control process shown in Figure 6, the target internal pressure is set with a degree of freedom so that the internal pressure of tire 4 at the first temperature and the internal pressure of tire 4 at the second temperature can be any value as long as they are within the specified ranges of tire 4, respectively.

[0090] On the other hand, at construction sites and mines in the mountains, work is carried out in the face of nature, so situations may arise where a vehicle's planned operation period was initially set to be during the winter, but the planned operation period is extended until the end of summer, making it impossible to provide an opportunity to adjust the internal pressure of the tires 4 mounted on the vehicle during the planned operation period. In preparation for such a case, if the average minimum temperature during the planned operation period is lower than the minimum temperature on the day the internal pressure of the tires 4 is to be adjusted, it is preferable to adjust the internal pressure of the tires 4 at the first temperature so that the internal pressure of the tires 4 is at the lower limit of the specified range for the tires 4.

[0091] For example, when adjusting the internal pressure of tire 4 in the fall in preparation for the planned winter operation period, assume that the minimum temperature during the planned operation period is -20°C. In this case, according to the temperature information of tire 4 shown in Fig. 7, the tire temperature will drop to -20°C.

[0092] Therefore, the CPU 21 calculates the internal pressure of the tire 4 under an ambient temperature environment such that the internal pressure of the tire 4 becomes 700 kPa, which is the lower limit of the specified range, when the tire temperature is −20° C., as the target internal pressure.

[0093] In this way, by adjusting the internal pressure of tire 4 at the first temperature to the lower limit of the specified range of tire 4, the difference between the internal pressure of tire 4 at the second temperature and the upper limit of the specified range of tire 4 can be maximized, thereby ensuring a margin for increase in the internal pressure of tire 4.

[0094] If the vehicle is operated in a season with a higher minimum temperature than the minimum temperature during the originally planned operating period, the tire temperature will rise, and the internal pressure of the tire 4 will also rise accordingly. However, as described above, by adjusting the internal pressure of the tire 4 at the first temperature to the lower limit of the specified range for the tire 4, a margin for the increase in the internal pressure of the tire 4 is secured. Therefore, the pressure of the tire 4 is less likely to exceed the upper limit of the specified range for the tire 4, compared to when the internal pressure of the tire 4 at the first temperature is not adjusted to the lower limit of the specified range for the tire 4.

[0095] 9 is a diagram showing an example of the tire temperature-internal pressure relationship when the internal pressure of tire 4 at the first temperature is set to the lower limit of the specified range for tire 4, for the temperature information of tire 4 shown in Fig. 7. In order to set the internal pressure of tire 4 at the first temperature to the lower limit of the specified range for tire 4 when the ambient temperature is 27°C, the target internal pressure should be set to 830 kPa.

[0096] In this case, if the minimum temperature in summer is 25°C, even if the vehicle is operated from winter to summer, the internal pressure of tire 4 corresponding to the second temperature in the summer (70°C in the example of Figure 9) obtained from the temperature information of tire 4, which changes depending on the vehicle's operating pattern, will be 949 kPa, and the internal pressure of tire 4 will be within the specified range.

[0097] On the other hand, a situation may arise in which the vehicle's planned operation period was initially set to the summer period, but the planned operation period is extended until the end of winter, making it impossible to provide an opportunity to adjust the internal pressure of the tires 4 mounted on the vehicle during the planned operation period. In preparation for such a case, if the average value of the minimum temperature during the planned operation period is higher than the minimum temperature on the day when the internal pressure of the tires 4 is to be adjusted, the CPU 21 of the control device 1 adjusts the internal pressure of the tires 4 at the second temperature so that the internal pressure of the tires 4 is the upper limit value of the specified range for the tires 4.

[0098] For example, when adjusting the internal pressure of tire 4 in the spring in preparation for the planned summer operation period, assume that the minimum temperature during the planned operation period is 25°C. In this case, according to the temperature information of tire 4 shown in Figure 7, the tire temperature will rise to 70°C.

[0099] Therefore, the CPU 21 calculates the internal pressure of the tire 4 under an ambient temperature environment such that the internal pressure of the tire 4 becomes 960 kPa, which is the upper limit of the specified range, when the tire temperature is 70° C., as the target internal pressure.

[0100] In this way, by adjusting the internal pressure of tire 4 at the second temperature to the upper limit value of the specified range for tire 4, the difference between the internal pressure of tire 4 at the first temperature and the lower limit value of the specified range for tire 4 can be maximized, thereby ensuring a margin for possible reduction in the internal pressure of tire 4.

[0101] If the vehicle is operated in a season with a lower minimum temperature than the minimum temperature during the originally planned operating period, the tire temperature will drop, and the internal pressure of the tire 4 will also drop accordingly. However, as described above, by adjusting the internal pressure of the tire 4 at the second temperature to the upper limit of the specified range for the tire 4, a margin for possible drop in the internal pressure of the tire 4 is secured. Therefore, the pressure of the tire 4 is less likely to fall below the lower limit of the specified range for the tire 4, compared to when the internal pressure of the tire 4 at the second temperature is not adjusted to the upper limit of the specified range for the tire 4.

[0102] Fig. 10 is a diagram showing an example of the tire temperature-internal pressure relationship when the internal pressure of tire 4 at the second temperature is set to the upper limit of the specified range for tire 4, based on the temperature information of tire 4 shown in Fig. 7. In order to set the internal pressure of tire 4 at the second temperature to the upper limit of the specified range for tire 4 when the ambient temperature is 27°C, the target internal pressure should be set to 840 kPa.

[0103] In this case, if the minimum temperature in summer is 25°C, even if the vehicle is operated from summer to winter, the internal pressure of tire 4 corresponding to the first temperature in winter (-20°C in the example of Figure 10) obtained from the temperature information of tire 4, which changes depending on the vehicle's operating pattern, will be 708 kPa, and the internal pressure of tire 4 will be within the specified range.

[0104] While one aspect of the internal pressure regulation system has been described above using the embodiment, the disclosed form of the internal pressure regulation system is merely an example, and the form of the internal pressure regulation system is not limited to the scope described in the embodiment. Various modifications or improvements can be made to the embodiment without departing from the gist of the present disclosure, and forms incorporating such modifications or improvements are also included in the technical scope of the disclosure. For example, the order of the control process shown in FIG. 6 may be changed without departing from the gist of the present disclosure.

[0105] In the internal pressure adjusting device according to this embodiment, if there is no value that satisfies the above-described formulas (1) and (2), a value that satisfies either the modified formula (1) or the modified formula (2) may be set as the target internal pressure. If a value that satisfies formula (1) is set as the target internal pressure, it is possible to determine that an operation that reduces the load on the tire 4 is to be adopted in order to suppress a rise in the temperature of the tire 4. If a value that satisfies formula (2) is set as the target internal pressure, it is possible to determine that an operation that warms up the tire 4 with a low load is to be adopted in order to raise the temperature of the tire 4 before operation.

[0106] In the embodiment, the control process is implemented by software. However, the process equivalent to the flowchart shown in Fig. 6 may be implemented by hardware. In this case, the process can be performed faster than when the control process is implemented by software.

[0107] In the embodiments, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPU 21) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0108] Furthermore, the operations of the processors in the embodiments may not only be performed by a single processor, but may also be performed by multiple processors located at physically separate locations working together. Furthermore, the order of the operations of the processors is not limited to the order described in the embodiments, and may be changed as appropriate.

[0109] In the embodiment, an example in which the control program is stored in the ROM 22 has been described, but the storage location of the control program is not limited to the ROM 22. The control program of the present disclosure may also be provided in a form recorded on a storage medium readable by the computer 20. For example, the control program may be provided in a form recorded on an optical disk such as a CD-ROM (Compact Disk Read Only Memory) or a DVD-ROM (Digital Versatile Disk Read Only Memory). The control program may also be provided in a form recorded on a portable semiconductor memory such as a USB (Universal Serial Bus) memory or a memory card. The ROM 22, the non-volatile memory 24, a CD-ROM, a DVD-ROM, a USB memory, and a memory card are examples of non-transitory storage media.

[0110] 11, the control device 1 may download a control program from an external device 7 connected to the communication line 5B via the communication unit 14 and store the downloaded control program in the storage device. In this case, the CPU 21 of the control device 1 reads the control program downloaded from the external device 7 and executes the control process. [Explanation of symbols]

[0111] 1. Control device 2 Temperature Sensors 3. Internal pressure adjustment device 4 tires 5A(5B) Communication lines 6A(6B) Line 7 External device 8. Points representing the lowest temperatures 9 Tire temperature dots 11 Sensor input section 12 Information acquisition department 13 Adjustment section 14 Communications Department 15 Temperature DB 16 Tire Information DB 20 Computer (arithmetic unit) 21 CPU 22 ROM 23 RAM 24 Non-volatile memory 25 I / O 26 Bus 27 Communication Unit 28 Input Units 29 Display Unit

Claims

1. The internal pressure of the tire is adjusted using a result calculated from the predicted temperature for a future use period in which the vehicle equipped with the tire is scheduled to be used and the temperature range of the tire that varies depending on the operation pattern of the vehicle, so that the internal pressure of the tire during the use period falls within a predetermined specified range recommended for the tire. How to adjust internal pressure.

2. the tire temperature zone is a temperature zone for each operating state of the vehicle, which is expressed by a lower limit relative temperature and an upper limit relative temperature with respect to a reference temperature that changes daily; calculate an internal tire pressure at an air temperature of a location where the internal tire pressure adjustment is performed, such that the internal tire pressure during the usage period falls within the specified range even if the temperature of the tire changes from a first temperature corresponding to a lower limit relative temperature of the temperature range with the lowest lower limit relative temperature to a second temperature corresponding to an upper limit relative temperature of the temperature range with the highest upper limit relative temperature; The internal pressure of the tire is adjusted so as to approach the calculated internal pressure. The method for adjusting internal pressure according to claim 1 .

3. If the average value of the reference temperature during the usage period is lower than the reference temperature on the day when the internal pressure of the tire is adjusted, the internal pressure of the tire of the vehicle is adjusted so that the internal pressure of the tire at the first temperature is the lower limit of the specified range, and if the average value of the reference temperature during the usage period is higher than the reference temperature on the day when the internal pressure of the tire is adjusted, the internal pressure of the tire of the vehicle is adjusted so that the internal pressure of the tire at the second temperature is the upper limit of the specified range. The method for adjusting internal pressure according to claim 2 .

4. The reference temperature is the lowest temperature during the use period included in the predicted temperature. The internal pressure adjusting method according to claim 2 or 3.

5. The temperature range of the tire is set using any one of the following: a temperature obtained from a sensor attached to the tire whose internal pressure is to be adjusted and measuring the temperature of the tire; a temperature of the tire obtained from a simulation result of driving the vehicle along the driving pattern of the vehicle; and a temperature obtained from a tire of the same type as the tire that is attached to another vehicle that operates in the same driving pattern as the vehicle on which the tire is attached. The internal pressure adjusting method according to any one of claims 1 to 4.

6. The predicted temperature is estimated using past temperatures for the same period as the usage period. The internal pressure adjusting method according to any one of claims 1 to 5.

7. The tire whose internal pressure is to be adjusted is a tire for an industrial vehicle. The internal pressure adjusting method according to any one of claims 1 to 6.

8. an acquisition unit that acquires a predicted temperature for a future use period in which a vehicle equipped with the tire is scheduled to be used and a temperature range of the tire that changes depending on an operation pattern of the vehicle; a control unit that performs control to adjust the internal pressure of the tire using a result calculated from the predicted air temperature and the temperature zone of the tire acquired by the acquisition unit so that the internal pressure of the tire during the usage period falls within a predetermined specified range recommended for the tire; and An internal pressure adjustment device equipped with

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