Air charging device

Abstract

To provide an air charging device capable of simultaneously charging air into multiple tires.SOLUTION: An air charging device includes an automatic charging unit in the middle of an air flow path, a switching operation valve located between the automatic charging unit and a branch manifold, an automatic on-off valve that opens / closes the air flow path between an air supply source and the automatic charging unit, an automatic exhaust valve that releases the air flow path to the atmosphere, and a pressure sensor. The switching operation valve is configured to switch between an open state that connects the upstream side to the downstream side and a standby state that opens the upstream side to the atmosphere and closes the downstream side. A control unit includes a storage unit that stores a set pressure P1 that determines the charging pressure to the tire, a charge start pressure P0 that determines a lower limit pressure value being a pressure value smaller than the set pressure P1 and starting air charging automatically, and a tire connection confirmation pressure P2 being the pressure value greater than the set pressure P1 and confirming the connection state of the tire, starts air charging on the basis of the charge start pressure P0 and performs automatic control to approach the charge pressure on the basis of the set pressure P1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an air filling device for automatically filling tires of automobiles or the like with air. [Background technology]

[0002] In order to drive safely, vehicles such as cars and trucks use an air inflation device to replenish air in their tires until the air pressure reaches the recommended pressure or is close to the recommended pressure.

[0003] In an air filling device, air is supplied from an air supply source to an air chuck connected to the end of a hose, which is the downstream air flow path. The valve of the tire to be filled is then connected to this air chuck to fill the tire with air. The simplest air filling device is one in which a pressure reducing valve is placed in the air flow path, a target filling pressure is set in this pressure reducing valve, and air is sent from the air supply source. However, with this method, although air is filled vigorously at the start of filling, as the target filling pressure is approached, the pressure reducing valve is throttled and the air flow rate through the flow path is drastically reduced, so it takes a long time to complete filling. For this reason, an air filling device is used that does not install a pressure reducing valve for setting a target filling pressure in the air flow path, but instead uses a pressure sensor to monitor the pressure value and manually operate the opening and closing valve to fill at high speed.

[0004] When filling air by manual operation using a pressure sensor, the worker must quickly finish filling the air and remove the air chuck when the target air pressure is reached. In that case, it is necessary to keep visually checking the pressure sensor during filling, which is time-consuming, so an air filling device that can automatically fill the air until the target air pressure is reached by automatic control and has an automatic safety control function has been disclosed (see Patent Document 1).

[0005] In the automatically controlled air filling device disclosed in the above Patent Document 1, when an air chuck is connected to a tire and a filling start button is manually pressed to start operation under automatic control, a safety check process is first performed to check the connection between the tire and the air chuck, and then automatic filling control is performed. That is, when a tire in a positive pressure state due to remaining air is connected to an air chuck (an open-type air chuck described later), a pressure increase in the air flow path is detected by a pressure sensor, and it is determined that the tire is properly connected, and an automatic opening and closing valve connected to an air supply source is opened to send in air, so that high-speed filling at a large flow rate can be automatically performed. By checking the connection of the tire in this way, it is possible to prevent erroneous operation in which air continues to be sent from the air supply source without being connected by mistake.

[0006] Here, the type of air chuck used will be explained. Generally, there are two types of air chucks: an open type in which the inside of the air chuck is open (atmospheric pressure) when the tire valve is not connected, and a closed type in which the inside of the air chuck is always closed when the tire valve is not connected. In the automatically controlled air filling device described in the above Patent Document 1, the air flow path at the position where the pressure is detected needs to be at atmospheric pressure before a tire with positive pressure is connected, so an open type air chuck is used to keep the inside of the air chuck (inside the air flow path) at atmospheric pressure. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-123248 Summary of the Invention [Problem to be solved by the invention]

[0008] The conventional air filling device described in the above document is equipped with only one open-type air chuck, and tires are connected to the air chuck one by one to fill them with air. When filling multiple tires with air, the tires are replaced one by one and the same filling process is repeated, so the filling time is proportional to the number of tires to be filled. In order to fill multiple tires at the same time in a short period of time, multiple air filling devices must be used at the same time, which not only increases the cost of the device, but also requires storage space for multiple devices and maintenance work for multiple devices.

[0009] Therefore, it is preferable to have an air filling device that can fill multiple tires with air at the same time.To achieve this, it is possible to make an air filling device in which the air flow path is branched midway and multiple air chucks are connected to the end of the flow path. In that case, if an open-type air chuck is used as in the conventional device, air will be released from the air chuck to which no tire is connected, so it is necessary to connect tire valves to all air chucks or to seal the air chucks that are not being used. Also, after connecting and filling multiple tires at the same time, if the air chuck of one of the tires is removed, the filling air of the tires connected to the other air chucks will flow back toward the removed air chuck and be released into the atmosphere.

[0010] On the other hand, if a closed type air chuck is used, air will not be released even if there is an air chuck to which no tire is connected when filling the tires. Also, after connecting and filling multiple tires simultaneously, even if one tire is removed from the air chuck, the air flow path remains closed and the air filled in the other tires will not be released. However, even after all the tires are removed, air at the same pressure as the tire filling pressure remains in the air flow path and cannot be discharged.

[0011] In that case, even if you connect the next tire and continue to fill it with air while the automatic control is running, there will still be residual air from the previous time remaining in the air passage. Therefore, although the pressure sensor detects that the air pressure is positive, it is not possible to determine whether this is the residual air pressure caused by the connection of the next tire or the residual air pressure when no tire is yet connected, so with this configuration it is difficult to correctly confirm whether a tire is connected or not.

[0012] The object of the present invention is to provide an air filling device that can fill multiple tires with air at high speed up to the filling pressure without using a pressure reducing valve for setting a target filling pressure, that can fill one or multiple tires simultaneously with air under automatic control until the set pressure is reached without the need to continue visually checking the pressure during filling, and that can safely fill the tires with air by automatically checking the connection between the tire and the air chuck before filling the tires with air. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides the following technical solutions. That is, the air filling device of the present invention is an air filling device in which a plurality of branch flow paths (14a to 14d) are connected in parallel to air flow paths (12a, 12b) connected to an air supply source (11) via a branching manifold (13), a closed-type air chuck (15a to 15d) is connected to an end of each of the branch flow paths (14a to 14d), and at least one tire is connected to any of the air chucks (15a to 15d) to fill it with air. An automatic filling unit (22) controlled by a control unit (20) is provided midway along the air paths (12a, 12b), and a switching operation valve (23) is provided between the automatic filling unit (22) and the branching manifold (13). The automatic filling unit (22) includes an automatic on-off valve (24) for opening and closing the air flow path (12a) between the air supply source (11) and the automatic filling unit (22), and a pressure sensor (26) for detecting pressure at every predetermined sampling time Ts. The switching operation valve (23) is configured to switch between an open state in which the upstream side and the downstream side are connected to each other and a standby state in which the upstream side is opened to the atmosphere and the downstream side is closed. The control unit (20) is equipped with a memory unit (20a) for storing a set pressure P1 that determines the filling pressure of the tire, a filling start pressure P0 that is a pressure value smaller than the set pressure P1 and determines a lower limit pressure value for automatically starting air filling, and a tire connection confirmation pressure P2 that is a pressure value larger than the set pressure P1 and confirms the connection state of the tire. Air filling is started based on the filling start pressure P0, and then the connection state of the tire and the air chuck is confirmed based on the tire connection confirmation pressure P2, and automatic control is performed to approach the filling pressure based on the set pressure P1. Effect of the Invention

[0014] According to the present invention, closed-type air chucks are connected to the ends of multiple branch flow paths, so that one or multiple tires can be connected and filled with air simultaneously. Moreover, when one of the air chucks is detached from the tire after air filling is complete, the filling air of the tire simultaneously connected to the other air chuck does not flow back toward the detached air chuck and be released to the outside, so that the tire can be reliably filled to the desired pressure.

[0015] In addition, when the closed-type air chuck is removed from the tire after the tire has been filled with air, the compressed air from the previous filling operation remains in the branch flow path. If the work is completed without releasing the remaining compressed air in the branch flow path and the next air filling operation is started, even if the pressure measured by the pressure sensor rises above the filling start pressure P0 when the switching operation valve is opened, it is difficult to distinguish whether the pressure rise is due to the residual pressure remaining in the air flow path (branch flow path) when the tire is not connected, or the pressure rise when the tire is connected to the air flow path. According to the present invention, after filling is started at the filling start pressure P0, which is a pressure value lower than the set pressure P1, it is confirmed whether the pressure in the air flow path rises suddenly to the tire connection confirmation pressure P2, which is a pressure value higher than the set pressure P1. When a tire is not connected, high-pressure air from the air supply source is supplied to the small volume of only the air flow path (branch flow path), causing the pressure in the air flow path to rise sharply and exceed the tire connection confirmation pressure P2, but when a tire is connected, air is supplied to the combined volume of the air flow path and the tire, and the pressure rise is mitigated by the effect of the large volume of the tire, and automatic control is activated to suppress the pressure rise before it reaches the tire connection confirmation pressure P2. Therefore, it is possible to reliably and instantly determine whether a tire is connected or not based on whether the tire connection confirmation pressure P2 is exceeded. This makes it possible to prevent erroneous operation when a tire is not connected. [Brief description of the drawings]

[0016] [Figure 1] 1 is an external view of an air filling device according to an embodiment of the present invention; [Diagram 2]FIG. 2 is a block diagram of the air filling device of FIG. 1. [Diagram 3] FIG. 2 is an air circuit diagram showing an air flow path of the air filling device of FIG. 1. [Figure 4] 2 is a cross-sectional view showing the configuration of a switching valve of the air filling device of FIG. 1. [Diagram 5] 4 is a flowchart showing an example of the operation of the air filling device of FIG. 1. [Figure 6] FIG. 4 is a block diagram of an air filling device according to another embodiment of the present invention. [Figure 7] 7 is a cross-sectional view showing the configuration of a switching valve of the air filling device of FIG. 6. [Figure 8] 7 is a flowchart showing an example of the operation of the air filling device of FIG. 6. [Figure 9] FIG. 4 is an external view of an air filling device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is an external view of an air filling device M according to an embodiment of the present invention, Fig. 2 is a block diagram showing the configuration of the air filling device M, and Fig. 3 is an air circuit diagram explaining the air flow path of the air filling device M. The air filling device M comprises a vertically long machine frame 1 that can be moved on wheels, and an automatic filling section 22, a switching valve 23, and a branching manifold 13 are fixed to this machine frame 1.

[0018] Four hoses 14a-14d that serve as branching flow paths are connected to the branching manifold 13. The length of each of the hoses 14a-14d is about 10 m, and closed-type air chucks 15a-15d for connecting to the valves of the tires T1-T4 are provided at their ends. In addition, a power supply battery 31 is mounted below the machine frame 1 to supply power to devices that require power (such as the control unit 20 described below). The machine frame 1 is provided with a dummy valve 32 having a through hole, so that when it becomes necessary to release air from the closed-type air chucks 15a to 15d, the air can be released by connecting this valve.

[0019] The automatic filling unit 22 is made of a housing equipped with an operation panel, and high-pressure air supplied from the air supply source 11 (air compressor, etc.) is sent into the housing from an air inlet (not shown) provided on the wall of the housing. The housing also includes an upstream air flow path 12a connecting the air supply source 11 and the automatic filling unit 22, a control manifold 21 for connecting a control device to the air flow path, and a downstream air flow path 12b connecting the control manifold 21 and a switching operation valve 23.

[0020] An automatic on-off valve 24 (normally closed type) consisting of an electromagnetic two-way valve that opens and closes the air flow path 12a is provided at a position where the upstream air flow path 12a is connected to the control manifold 21. Also, at a position downstream of the automatic on-off valve 24, an automatic exhaust valve 25 (normally closed type) consisting of an electromagnetic two-way valve that opens the air flow path 12b (including the internal space of the control manifold 21) downstream of the automatic on-off valve 24 to the atmosphere, and a pressure sensor 26 that detects the pressure in the internal space of the control manifold 21 are connected. A speed controller may be provided on the discharge side of the automatic discharge valve 25 so that the flow rate (discharge speed) of air discharged from the control manifold 21 can be adjusted.

[0021] The automatic filling unit 22 includes a housing therein a control unit 20 that automatically controls an automatic on-off valve 24 and an automatic discharge valve 25 until the target filling pressure of the tire is reached. The control unit 20 is configured as a computer system including a processor such as a CPU and a storage unit 20a (memory), and performs automatic filling by executing a program stored in the storage unit 20a.

[0022] The control unit 20 is also equipped with an input unit 20b for performing input operations using various buttons, such as a start button 19a for turning the power ON, an input operation button 19b for setting the control parameters required for automatic filling, a filling button 19c for manually opening the automatic opening / closing valve 24 on an exceptional basis when filling a tire with air that has dropped too low or a tire that has been newly mounted on a wheel, and an emergency stop button 19d for manually stopping the filling operation in an emergency during the air filling operation, a display unit 20c for displaying various numerical data as well as warnings and status indications, and a speaker 20d for generating sounds such as warning sounds, and these are attached to the control panel.

[0023] The control unit 20 is equipped with a timer function, and after startup, receives a pressure signal from the pressure sensor 26 at predetermined sampling times Ts (e.g., 1 to 5 seconds), and controls the automatic opening / closing valve 24 and the automatic drain valve 25 based on this pressure signal and the control parameters stored in the memory unit 20a.

[0024] After the control unit 20 starts up, it monitors the timer, and if it detects that no new button operation or warning processing to prompt the operator to perform some operation or processing has been performed for a specified waiting time Tw (for example, 10 minutes), and that the pressure signal from the pressure sensor 26 remains constant, it determines that processing is not progressing, and automatically and forcibly turns the power OFF (power auto-off function), after which it is not possible to proceed with processing unless a safety check is performed and the power is turned ON again. The waiting time Tw until the power auto-off function is activated can be set arbitrarily using the input operation button 19b. In addition, timer monitoring is also performed when a warning process is performed to prompt the operator to perform an operation and the operation wait state is entered, but the waiting time Tb (for example, about one minute) at that time can also be set. The waiting time Tb for this warning process is set to a time that is sufficiently shorter than the waiting time Tw for the power auto-off function, so that the waiting time Tb for the warning process is up before the power auto-off function is activated, causing the warning process to be repeated, and the power auto-off function is not activated during timer monitoring based on the waiting time Tb.

[0025] In this device, the control parameters stored in the memory unit 20a include "set pressure P1," "filling start pressure P0," and "tire connection confirmation pressure P2," which are pressure values ​​to be compared with the pressure detected by the pressure sensor 26. In addition, when it is necessary to fill a variety of tires, from tires for large vehicles to tires for small vehicles, the "sampling time Ts," which is the time interval at which the pressure sensor 26 repeats pressure measurements, can also be changed.

[0026] The set pressure P1 is used as the target pressure value for air filling, and is set to approximately 200 to 1000 kPa depending on the type of tire to be filled. Note that all pressure values ​​described in this book use gauge pressure with atmospheric pressure set to 0 kPa (reference value).

[0027] The filling start pressure P0 is a pressure value for checking whether the pressure downstream of the control manifold 21 is atmospheric pressure (gauge pressure 0 kPa), and is set to a pressure value sufficiently smaller than the set pressure P1, specifically, a lower limit sensing pressure close to atmospheric pressure. There are several possible reasons why the pressure sensor 26 may detect an air pressure close to 0 kPa, such as when a tire is not connected, when the remaining air pressure of a connected tire is close to 0 kPa due to an abnormality such as a puncture, when the tire itself is normal but the air has simply been completely lost and is at 0 kPa, when the tire has just been assembled to a wheel, or when a leak has occurred in the air flow path of the air filling device M.

[0028] Normally, even if air pressure has not been managed for a long time, some residual air pressure remains in a tire in use, creating a positive pressure, so when a tire with residual positive air pressure is connected to the air chuck, the air flow path becomes positive. If a pressure value (e.g., 20 to 80 kPa) slightly more positive than atmospheric pressure is set as the filling start pressure P0, when the air flow path changes from atmospheric pressure to a positive pressure exceeding the filling start pressure P0, it can be confirmed that the tire is connected to the air flow path. Therefore, when air filling starts automatically, it can be used as one of the control parameters for safety confirmation of whether the tire is connected to the flow path. Specifically, when the control unit 20 performs automatic filling, the filling start pressure P0 is used as the lower limit pressure value at which filling can be started, and if the pressure sensor 26 detects only an air pressure lower than the filling start pressure P0, the automatic opening / closing valve 24 will not be opened automatically, and will only be opened exceptionally by manually turning it ON using the filling button 19c after the operator has performed a safety check.

[0029] As described above, the purpose of setting the filling start pressure P0 of about 20 to 80 kPa as the lower limit sensing pressure is to allow the operator to perform safety confirmation work when the pressure downstream of the control manifold 21 has dropped to almost atmospheric pressure. In this embodiment, the setting range of the filling start pressure P0 can be expanded to the positive pressure side, from "20 kPa to less than the set pressure P1". By setting the lower limit pressure value that allows automatic filling to start on the more positive pressure side, it is possible to set any pressure value below the set pressure P1, not just when the pressure is almost atmospheric pressure, and it is possible to set even stricter conditions for prompting the operator to perform safety confirmation work.

[0030] The tire connection confirmation pressure P2 is a pressure value for confirming that at least one tire is connected to the air chucks 15a to 15d, and is set to a pressure value sufficiently larger than the set pressure P1. When no tire is connected to the air chucks 15a to 15d, the volume of the air flow path downstream from the control manifold 21 to the air chucks 15a to 15d is small. Therefore, if compressed air remains in the flow path from the switching operation valve 23 to the air chucks 15a to 15d, when the switching operation valve 23 is opened to release the flow path blocking, the pressure inside the flow path downstream of the switching operation valve 23 flows back to the control manifold 21, and the pressure sensor 26 detects the pressure, the automatic opening and closing valve 24 is opened, and air filling is started. Then, immediately after that, the pressure value in the air flow path rises sharply (the maximum pressure value when it rises is the pressure value of the high-pressure air itself supplied from the air supply source 11). If the measured pressure value P detected by the pressure sensor 26 exceeds the set pressure P1 and also exceeds the tire connection confirmation pressure P2 before the next sampling time Ts, it is instantly determined to be abnormal and an error signal is generated to close the automatic on-off valve 24 and bring the filling operation to an emergency stop, and at the same time, the automatic discharge valve 25 is opened to release the air in the flow path to the atmosphere.

[0031] On the other hand, if even one tire is connected, the downstream volume increases significantly, suppressing a sudden pressure rise, so that after the first (or second or so) sampling time Ts has elapsed, the pressure measured by the pressure sensor 26 exceeds the set pressure P1, causing air to begin to be discharged from the automatic discharge valve 25 by automatic control, and the tire connection confirmation pressure P2 is exceeded, so that the automatic control is activated and the automatic opening / closing valve 24 is closed to perform an emergency stop, thereby preventing a situation from occurring where this safety function is activated. Therefore, the tire connection confirmation pressure P2 is used as a threshold value for confirming that at least one tire is connected to the air chuck.

[0032] The sampling time Ts of the pressure sensor 26 can be used as a control parameter for adjusting the response speed of the pressure sensor. If the sampling time Ts is set to a large value, the response of the pressure sensor 26 will be slow, and the opening and closing response of the automatic on-off valve 24 and the automatic exhaust valve 25 will also be slow, so that the amount of air flowing into the air flow path and the amount of air exhausted can be greatly changed, and the pressure fluctuation range in the air flow path can be increased. Specifically, in this embodiment, the sampling time Ts can be set to about 1 to 5 seconds.

[0033] A switching valve 23 connected to the air flow path 12b is provided downstream of the automatic filling unit 22, and the branching manifold 13 is further connected (directly) to the downstream side of the switching valve 23. The switching valve 23 is configured to have a flow path configuration that switches between an "open state" (first state) that connects the upstream side (automatic filling unit 22 side) and the downstream side (branching manifold 13 side), and a "standby state" (second state) that opens the upstream side (automatic filling unit 22 side) to the atmosphere and closes the downstream side (branching manifold 13 side). Such a flow path configuration can be realized by using a mechanical or electromagnetic three-way valve with three ports. That is, a flow path is formed by connecting the upstream side (automatic filling section 22) to the first port (1P), the downstream side (branching manifold 13) to the second port (2P), and the third port (3P) as an atmospheric release port, and this can be realized by switching between a first state in which the first port (1P) and the second port (2P) are connected, and a second state in which the first port (1P) and the third port (3P) are connected (see Figure 3).

[0034] In this embodiment, in order to prevent erroneous operation, a mechanical valve is used that can be directly slid up and down by hand and that allows the user to see at a glance whether the valve is in an open or standby state from changes in its external shape.

[0035] FIG. 4 is a cross-sectional view showing the configuration of a mechanical valve which is one embodiment of the switching valve 23 used in the present invention, where (a) shows the open state and (b) shows the standby state. The switching operation valve 23 comprises a straight pipe-shaped body 51 and a hollow cylindrical cylinder 52 that is attached coaxially to surround the outer periphery of the body 51. The upper end 55 of the body 51 is connected to the air flow path 12b, and the lower end 56 is connected to the opening position of the flow path of the branching manifold 13. An upper flange 53 is provided on the upper outer periphery of the body 51, and a lower flange 54 is provided on the lower outer periphery, with the cylinder 52 slidably attached between these upper and lower flanges. In order to allow the cylinder 52 to be positioned between the upper and lower flanges, the attachment surface of the lower flange 54 to the body 51 is tapered so that it can be removed from the body 51 and fixed in a fixed position on the body 51.

[0036] A sealing block 57 for blocking is fitted inside the straight pipe of the body 51 at a position slightly above the midpoint between the upper flange 53 and the lower flange 53, thereby separating the inside of the pipe of the body 51 into an upper space 61 and a lower space 62. A plurality of upper holes 58 and lower holes 59 are formed near the upper and lower sides of this sealing block 57 so as to penetrate the pipe wall of the body 51 (specifically, four locations in the circumferential direction at equal angular intervals).

[0037] A through hole for loosely fitting the body 51 along the axial direction is formed in the upper wall 52a and the lower wall 52b of the cylindrical cylinder 52, and a groove for fixing the O-rings 63, 64 is formed in the thick surface (inner peripheral wall) of the through hole. The frictional resistance generated by the contact between the O-rings 63, 64 attached to the groove and the outer peripheral surface of the body 51 allows the cylinder 52 to be stably stopped at two positions, an "upper position" where the upper wall 52b contacts the upper flange 53, and a "lower position" where the lower wall 52c contacts the lower flange 54, while maintaining airtightness of the contact surfaces. The cylinder 52 is also configured so that an inner diameter of the cylindrical side wall 52c is larger than the outer diameter of the body 51, thereby forming an inner cylinder space 65.

[0038] Here, the positional relationship between the cylinder 52 and the upper and lower holes 58 and 59 of the body 51 will be described. The switching operation valve 23 is formed so that, when the cylinder 52 is slid to the "upper position", the upper hole 58 and the lower hole 59 are included in the cylinder internal space 65. This forms a flow path that communicates from the flow path 12b through the upper space 61, the upper hole 58, the cylinder internal space 65, the lower hole 59, and the lower space 62 to the branching manifold 13, and the "open state" can be achieved. When the cylinder 52 is slid to the "lower position", the upper hole 58 is located outside the cylinder 52, and the lower hole 59 is formed in a position contained within the intra-cylinder space 65. As a result, the upstream side of the upper space 61 is open to the atmosphere, and the downstream side of the lower space 62 is closed by the intra-cylinder space 65, making it possible to enter a "standby state". In this way, switching between the open state and the standby state is performed by directly operating the cylinder 52 up and down with a hand, so that the state of the switching operation valve 23 can be intuitively grasped from the change in position of the cylinder 52 relative to the upper flange 53 and the lower flange 54, the sound of air being discharged from the upper hole 58, etc.

[0039] Next, the air filling operation by the air filling device M will be described. In the air filling device M, two cases are assumed: a reset state in which the remaining air at positive pressure from the automatic on-off valve 24 to the air chucks 15a to 15d has been released to a gauge pressure of 0 kPa (atmospheric pressure state) (hereinafter referred to as initial state A), and a state in which remaining air at positive pressure (remaining air pressure at the time of previous filling) exists from the switching operation valve 23 to the air chucks 15a to 15d (hereinafter referred to as initial state B). In principle, the air filling device M starts air filling from either the initial state A or the initial state B.

[0040] The initial state A is a reset state in which the positive pressure air remaining in the flow path from the switching operation valve 23 to the air chucks 15a to 15d is released using a dummy valve 32 or the like (Figure 1) at the end of the previous air filling operation. The initial state B is a state in which, after the previous air filling operation has ended, the device M is waiting for the start of the next air filling operation without any remaining air being removed (without being reset).

[0041] Generally, various control devices such as valves and pressure sensors used in the air flow path of the air filling device M use packings that deteriorate due to the pressure load applied when the device is in a high-pressure state. Therefore, it is recommended to perform the reset operation using a dummy valve 32 (or a jig equivalent to a dummy valve) for each operation as much as possible, as this can reduce the occurrence of malfunctions. On the other hand, performing the reset operation for each operation is time-consuming for the worker and reduces work efficiency. Therefore, as a general rule, the work procedure is to perform the reset operation after each filling operation as much as possible to return the device to the initial state A, but if the next filling operation is performed consecutively or during a busy period for the worker, the reset operation is not performed and the device waits in the initial state B. At least at the end of each day's air filling operation, the packing is returned to its initial state A to prevent deterioration.

[0042] FIG. 5 is a flow chart showing the air filling operation performed by the air filling device M from the initial state A or the initial state B. (ST100) High-pressure air of 1300 kPa (varies depending on the compressor specifications) is supplied from the air supply source 11 to the air flow path 12a upstream of the automatic on-off valve 24. The automatic on-off valve 24 and the automatic exhaust valve 25 are closed, and the switching operation valve 23 is in a standby state (second state) where the upstream side (automatic filling unit 22 side) is at atmospheric pressure and the downstream side (branching manifold 13 side) is in a closed state. From the branching manifold 13 to the air chucks 15a to 15d, the pressure is 0 kPa (atmospheric pressure state) in the initial state A, and in the initial state B, the pressure is the remaining air pressure from the previous air filling.

[0043] (ST101) The start button 19a of the control unit 22 is pressed to turn the power ON. This activates each control device of the automatic filling unit 22, and the control of automatic filling is started. Pressure measurement at every sampling time Ts by the pressure sensor 26 is started. In addition, at the same time as the power is turned ON, timer monitoring of the control state is activated, and when it is determined that none of the operation buttons are pressed continuously during a predetermined waiting time Tw, no warning processing is performed continuously, and the measured value of the pressure sensor 26 does not change and processing is not progressing, timer monitoring of the power auto-off function starts, which automatically turns the power OFF. At this time, in order to urge the user to proceed with the air filling operation after confirming that the switching operation valve 23 is in the standby state, a confirmation instruction process (display by the display unit 20c, sound by the speaker 20d) is performed to confirm that the switching operation valve 23 is in the standby state. Next, the process proceeds to ST102.

[0044] (ST102) Next, the control parameters required for control are confirmed and changed using the input operation button 19b. Specifically, a set pressure P1, which is a target air pressure to be filled, is set according to the size and type of the tire to be filled with air. In addition, other control parameters such as the filling start pressure P0, the tire connection confirmation pressure P2, the sampling time Ts of the pressure sensor 26, the waiting time Tw until the power auto-off function is activated, and the waiting time Tb for warning processing, etc., are also reset if they are to be changed from the initial setting values ​​(or the previous setting values) input and saved in advance. Here, the set pressure P1 is set to 250 kPa, the filling start pressure P0 is set to 30 kPa, the tire connection confirmation pressure P2 is set to 700 kPa, the sampling time Ts is set to 2 seconds, the waiting time Tw for the power auto-off function is set to 10 minutes, and the waiting time Tb for warning processing, etc. is set to 1 minute.

[0045] (ST103) Next, at least one tire to be filled with air is connected to air chucks 15a to 15d. Here, it is assumed that one tire is connected to air chuck 15a and filled with air. Next, the process proceeds to ST104.

[0046] (ST104) The switching operation valve 23 is opened. If positive air pressure remains in the connected tire, the remaining air from the tire flows into the control manifold 21, resulting in a positive pressure (P>0). On the other hand, if there is no positive air pressure remaining in the connected tire (P=0), atmospheric pressure is maintained if the initial state A was selected in ST100, and if the initial state B was selected in ST100, the remaining air that was left from the branching manifold 13 to the air chucks 15a to 15d during the previous air filling is diffused into the flow path from the control manifold 21 to the tire, resulting in the pressure measured by the pressure sensor 26 being slightly more positive than atmospheric pressure (P>0).

[0047] (ST105) After the switching valve 23 is switched to the open state, the first pressure measurement is performed by the pressure sensor 26. This measured pressure P is compared with the filling start pressure P0 to check for tire abnormalities such as a puncture. If P≦P0, proceed to ST106, and if P>P0, proceed to ST109.

[0048] (ST106) If P≦P0 in ST105 (because the remaining air pressure in the tire has dropped too much), it is determined that there is a possibility of a tire abnormality, and the automatic on-off valve 24 is maintained in the closed state. At this time, the worker will recognize that the remaining air pressure in the tire has dropped to below the filling start pressure P0 and will not proceed because the automatic on-off valve 24 does not open and air filling does not proceed for a while, or by confirming that the pressure value displayed on the display unit 20c has dropped to below the filling start pressure P0. Except for cases where the cause of the drop in remaining air pressure is obvious, such as the air pressure being 0 kPa immediately after the tire and wheel have been assembled, the worker will perform a safety check to check for any abnormalities in the tire, such as a puncture, or a poor connection in the air flow path. If no abnormality is found as a result of the safety check work, or if the cause of the abnormality is eliminated and safety is confirmed, the air filling work can be continued, so as an exception, the filling button 19c for manually opening the automatic opening / closing valve 24 is turned ON, and the process proceeds to ST109. Also, if the state in which the fill button 19c cannot be turned ON continues for a while due to a safety check operation or the like in ST106, the process proceeds to ST107 to perform timer monitoring of the power auto-off function. Also, if an abnormality that cannot be dealt with for some reason is found, the emergency stop button 19d is turned on to interrupt or stop the process, and the operator leaves the current work flow. Alternatively, the switching operation valve 23 may be switched to a standby state or the power may be manually turned off depending on the abnormality. After that, after the abnormality is resolved, a safety check is performed, and the filling work is carried out from a new state returned to the initial state A or initial state B.

[0049] (ST107) When P≦P0 and the operator has not turned on the refill button 19c, timer monitoring of the waiting time Tw until the power auto-off function is activated is performed. That is, when none of the operation buttons are operated, no warning processing is performed, and the pressure signal value of the pressure sensor 26 measured at each sampling time Ts is not fluctuating (processing is not progressing), the process returns to ST105 and repeats the process flow up to ST106 and ST107. Then, the elapsed time T during the repetition of this process flow is measured and compared with the waiting time Tw, and while T≦Tw continues, the process returns to ST105 and repeats the process flow, and when T>Tw (the refill button 19c is not pressed during that time) the process proceeds to ST108.

[0050] (ST108) Since the waiting time Tw has elapsed without any processing progressing, a sound is emitted by the speaker 20d to inform the user that the power will be turned off as the power auto-off process, and the power is automatically turned off 1 to 2 minutes after this sound is emitted. If the operator subsequently wishes to continue the filling operation, the switching valve 23 is returned to the standby state, safety is confirmed, and then the power is turned ON again from the initial state B or initial state A to begin a new filling operation.

[0051] (ST109) The automatic on-off valve 24 is opened by automatic control by the control unit 20 (ST105) or by an ON signal (ST106) by manually operating the filling button 19c. This causes high-pressure air from the air supply source 11 to be fed downstream, filling the tire with air, and the pressure values ​​in the tire and the air flow path rise. Next, the process proceeds to ST110.

[0052] (ST110) When high-pressure air is supplied from the air supply source 11 downstream of the automatic on-off valve 24, the pressure value in the control manifold 21 rises, and the pressure sensor 26 detects this. At this time, the total volume downstream of the automatic on-off valve 24 (the total volume of the connected tire and the air flow path) is significantly different between when a tire is connected to the air chuck 15a and when a tire is not connected (because ST103 was not executed correctly by mistake). When a tire is not connected, the pressure in the air flow path rises significantly during one sampling time Ts compared to when a tire is connected. In other words, the pressure value in the control manifold 21 (and in the air flow path) greatly exceeds the set pressure P1 by the time the first (or second) sampling time Ts of the pressure sensor 26 has elapsed, and the pressure rises all at once to exceed the tire connection confirmation pressure P2. In contrast, when a tire is connected, the total volume of the tire and the air flow path is large, so the pressure rise during one sampling time Ts is mitigated. Even if the set pressure P1 is exceeded, the automatic opening / closing valve 24 is closed and the automatic exhaust valve 25 adjusts the pressure reduction to the set pressure P1 before the tire connection confirmation pressure P2, which is set sufficiently large, is reached, so the tire connection confirmation pressure P2 will never be exceeded. Therefore, by setting the upper limit pressure value, which is sufficiently larger than the set pressure P1, as the tire connection confirmation pressure P2, and preferably further adjusting the sampling time Ts, it becomes possible to confirm the connection between the air chucks 15a to 15d using the tire connection confirmation pressure P2 and the tire. That is, when the measured pressure P and the tire connection confirmation pressure P2 satisfy P ≧ P2, the process proceeds to ST201, and when P < P2, the process proceeds to ST111.

[0053] (ST111) The current pressure value is detected by the pressure sensor 26 at each sampling time Ts, and the process of bringing the air pressure of the tire closer to the set pressure P1 is performed by comparing the measured pressure P and the set pressure P1. That is, when P < P1, the automatic on-off valve 24 is opened (or maintained in the open state) and the pressure measurement is continued. When P > P1, since the pressure exceeds the set pressure P1, the process proceeds to ST112 to perform a pressure reduction process (or maintain the pressure reduction process). When P = P1, the process proceeds to ST113 to maintain the current air pressure.

[0054] (ST112) Since the measured pressure P exceeds the set pressure P1, the automatic on-off valve 24 is closed and the automatic discharge valve 25 is opened to perform a pressure reduction process of discharging a part of the filled air until the next sampling time Ts comes. Subsequently, the process returns to ST111 and the process is repeated.

[0055] (ST113) Since the measured pressure P is equal to the set pressure P1, the automatic on-off valve 24 is closed and the automatic discharge valve 25 is closed to perform a process of maintaining the current air pressure. Also, a completion process (filling completion display by the display unit 20c, sounding of the filling completion sound by the speaker 20d) notifying that the measured pressure P is equal to P1 is performed. Thereby, the operator is urged to remove the filled tire, and at the same time, the switching operation valve 23 is urged to be switched to the standby state for preparing to continue filling air into another tire. Further, the timer monitoring of the completion process by the waiting time Tb starts. Subsequently, the process proceeds to ST114.

[0056] (ST114) While the switching operation valve 23 remains in the open state, air of about the set pressure P1 (that is, the measured pressure P > P0) remains in the control manifold 21. However, when the switching operation valve 23 is switched to the standby state by the operator, the pressure in the control manifold 21 becomes the atmospheric pressure state (0 kPa). When it is detected by the pressure sensor 26 that the measured pressure P is in the atmospheric pressure state (that is, P ≤ P0), it is determined that the switching operation valve 23 has been switched to the standby state, and the process proceeds to ST116. On the other hand, when the measured pressure P of the pressure sensor 26 is P > P0, it is determined that the valve has not yet been switched from the open state, and the process proceeds to ST115 to continue the timer monitoring of the waiting time Tb.

[0057] (ST115) While the switching operation valve 23 remains in the open state (that is, when P > P0), the timer monitoring of the completion process started at ST113 continues. That is, the elapsed time T from the previous ST113 and the waiting time Tb are compared. When T < Tb, the process returns to ST114 and repeats the processing flow up to ST115. When the elapsed time T during which this processing flow is repeated becomes T ≥ Tb, the process returns to ST111 and repeats the processing flow up to ST115. At this time, each time the process proceeds to ST113, the completion process (filling completion display by the display unit 20c and sounding of the filling completion sound by the speaker 20d) is restarted, and the timer monitoring by the waiting time Tb is repeated. Thereafter, the completion process at ST113 is restarted as many times as necessary until the switching operation valve 23 is switched to the standby state. During this period, the timer monitoring of the power auto-off function is also being performed. However, since the waiting time Tw of the power auto-off function is set to be sufficiently longer than the waiting time Tb of the completion process, the waiting time Tb times out first and the completion process is repeated before the waiting time Tw elapses. Therefore, until the switching operation valve 23 is switched to the standby state at ST114, the power will not be turned off by the power auto-off function. When the switching operation valve 23 is switched to the standby state by the operator, the process proceeds to ST116.

[0058] (ST116) When the switching valve 23 is switched to the standby state, the air flow path returns to the initial state B. The filled tire is removed from the air chuck 15a and the air filling operation is completed. If another tire is to be filled next, the tire is connected. When the filling operation is to be completed, the dummy valve 32 is reset to return to the initial state A and the power is manually turned off.

[0059] (ST117) While the power is not manually turned off in ST116, timer monitoring continues based on the waiting time Tw. That is, when none of the operation buttons are operated, no warning processing is performed, and the pressure signal value of the pressure sensor 26 measured at each sampling time Ts is not fluctuating (processing is not progressing), the timer monitoring processing flow in ST117 is repeated. Then, the elapsed time T while this processing flow is being repeated is measured and compared with the waiting time Tw, and while T≦Tw continues, the process returns to ST117 to repeat the processing flow, and when T>Tw, the process proceeds to ST118.

[0060] (ST118) Since the waiting time Tw has elapsed, the automatic power off process is performed. That is, a sound is generated by the speaker 20d to inform the user that the power will be turned off, and the power is automatically turned off after a delay of 1 to 2 minutes after the sound is generated.

[0061] (ST201) If the measured pressure P is equal to or greater than the tire connection confirmation pressure P2 in ST110, it is determined that the tire is not connected, and a warning process for the pressure rise is performed (the display unit 20c displays the pressure rise, and the speaker 20d issues a sound to notify the user of the pressure rise). The automatic on-off valve 24 is closed and the automatic exhaust valve 25 is opened by the control unit 20, whereby the pressure inside the air flow path (from the control manifold 21 to the air flow paths 14a to 14d) is reduced so that it approaches atmospheric pressure (0 kPa). As the pressure reduction progresses, the pressure sensor 24 detects that the measured pressure P is less than the filling start pressure P0. The process then proceeds to ST202.

[0062] (ST202) When the pressure sensor 26 detects that P < P0, the control unit 20 switches the automatic discharge valve 25 to the closed state (while the automatic on-off valve 24 remains closed). In this embodiment, from the time when the pressure sensor 24 detects less than P0, a sufficient time delay (for example, 10 seconds) is provided until the air passage completely returns to the atmospheric pressure state (0 kPa) and stops changing, and then the automatic discharge valve 25 is closed. After the automatic discharge valve 25 is closed, an operation instruction process (operation instruction by the display unit 20c and the speaker 20d) is performed to prompt the confirmation operation that the tire is not connected and the operation of switching the switching operation valve 23 from the open state to the standby state, and the operator is waited to execute the process. Subsequently, the process proceeds to ST203.

[0063] (ST203) The operator confirms the connection status with the tire by receiving the operation instruction from the display unit 20b and the speaker 20c in ST202. Also, by switching the switching operation valve 23 to the standby state, the upstream side of the switching operation valve 23 becomes the atmospheric pressure state, and the downstream side also becomes the atmospheric pressure state and returns to the initial state A. Subsequently, the process proceeds to ST204.

[0064] (ST204) Connect the tire to the air chuck and perform a safety check. If there is no problem, return to ST104 and redo the filling operation. Through the above processing flow, even in an air filling device using a closed-type air chuck, the tire connection state can be confirmed and the filling operation can be performed safely. Note that the power auto-off function also operates in ST203. When the waiting time Tw until the power auto-off function operates elapses without the switching operation valve 23 being switched to the standby state by the operator, the power automatically turns off. After that, when turning on the power and resuming the filling operation, the operation is performed after confirming that the switching operation valve 23 has been switched to the standby state in ST101.

[0065] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to the drawings. Fig. 6 is a block diagram showing the configuration of an air filling device M' according to another embodiment of the present invention, and Fig. 7 is a cross-sectional view showing the configuration of the switching valve 23 of the air filling device M'. The external shape of the device is substantially the same as that of Fig. 1 (only the switching operation valve 23 explained in Fig. 7 is different), and the air flow path is also the same as the air circuit shown in Fig. 3. The air filling device M' of the second embodiment has the same basic structure as the air filling device M of the first embodiment, so in the following explanation, the same components are given the same reference numerals and some of the explanation will be omitted.

[0066] In the air filling device M', a microswitch 66 is provided on the lower surface of the upper flange 53 of the switching operation valve 23, and when the cylinder 52 slides to the "upper position" and abuts against the microswitch 66 (FIG. 7(a)), the microswitch 66 transmits an ON signal to the control unit 22 wirelessly or by wire. In addition to the set pressure P1, filling start pressure P0, tire connection confirmation pressure P2, sampling time Ts, waiting time Tw for the power auto-off function, and waiting time Tb for warning processing, etc., the storage unit 20a of the control unit 20 stores a waiting time Ta for starting measurement when an ON signal is received from the microswitch 66. The waiting time Ta is set to be sufficiently shorter than the waiting times Tw and Tb, and is set to be specifically set to about 3 to 5 seconds.

[0067] Therefore, when the cylinder 52 is slid to the "upper position" to open the switching operation valve 23, measurement of the waiting time Ta begins and communication is established from the downstream tires T1-T4 and hoses 14a-14d to the upstream control manifold 21, so that the pressure value detected by the pressure sensor 26 immediately becomes a value influenced by the residual air pressure downstream (the pressure range from atmospheric pressure to the residual air pressure in the tires).

[0068] Therefore, if the remaining air pressure of the connected tire is higher than the filling start pressure P0, the pressure value will exceed P0 before the waiting time Ta has elapsed, but if the remaining air pressure of the connected tire is about atmospheric pressure, it will not exceed P0 even after the waiting time Ta has elapsed. Therefore, if the remaining air pressure has not exceeded P0 when the waiting time Ta has elapsed, the control unit 20 determines that the remaining air pressure may have decreased due to a tire abnormality, and issues a warning (warning display, warning sound) to the operator to urge him or her to make a safety check. In this way, the control unit 20 can automatically issue a warning of a drop in remaining air pressure to prompt the operator to make a safety check, so that the operator can instantly check for safety without relying on his or her own judgment to determine whether the pressure will exceed the filling start pressure P0.

[0069] Next, a description will be given of the air filling operation by the air filling device M'. In this case, as in the first embodiment, air filling is started in principle from either the initial state A or the initial state B.

[0070] (ST300) High-pressure air of 1300 kPa (varies depending on the compressor specifications) is supplied from the air supply source 11 to the air flow path 12a upstream of the automatic on-off valve 24. The automatic on-off valve 24 and the automatic exhaust valve 25 are closed, and the switching operation valve 23 is in a standby state (second state) where the upstream side (automatic filling unit 22 side) is at atmospheric pressure and the downstream side (branching manifold 13 side) is in a closed state. From the branching manifold 13 to the air chucks 15a to 15d, the pressure is 0 kPa (atmospheric pressure state) in the initial state A, and in the initial state B, the pressure is the remaining air pressure from the previous air filling.

[0071] (ST301) The start button 19a of the control unit 22 is pressed to turn the power ON. This activates each control device of the automatic filling unit 22, and the control of automatic filling is started. Pressure measurement at every sampling time Ts by the pressure sensor 26 is started. In addition, at the same time as the power is turned ON, timer monitoring of the control state is activated, and when it is determined that none of the operation buttons are pressed continuously during a predetermined waiting time Tw, no warning processing is performed continuously, and the measured value of the pressure sensor 26 does not change and processing is not progressing, a power auto-off function is started to automatically turn the power OFF. Furthermore, in order to urge the user to proceed with the air filling operation after confirming that the switching operation valve 23 is in a standby state, a confirmation instruction process (display by the display unit 20c, sound by the speaker 20d) is performed to confirm that the switching operation valve 23 is in a standby state, and timer monitoring for the waiting time Tb is started. Next, the process proceeds to ST302.

[0072] (ST302) It is confirmed whether the current switching operation valve 23 is in an open state or a standby state. Specifically, when the microswitch 66 is not issuing an ON signal, it is determined to be in the standby state and the process proceeds to ST305. When the microswitch 66 is issuing an ON signal, it is determined to be in the open state and the process proceeds to ST303.

[0073] (ST303) If the valve is open (not in standby) in ST302, timer monitoring of the switching operation valve 23 continues with waiting time Tb, and the elapsed time T from the confirmation instruction process in ST301 is measured, and while T≦Tb, the process returns to ST302 and repeats the process flow up to ST303. If the valve is switched to the standby state in ST302 while this process flow is being repeated, the process proceeds to ST305, but if the valve remains open and T>Tb, the process proceeds to ST304.

[0074] (ST304) When T>Tb while the switching operation valve 23 remains open, a warning process (display by the display unit 20c, sound by the speaker 20d) is performed to prompt the operator to switch the switching operation valve 23 to the standby state. Then, the process returns to ST302 and repeats the process flow up to ST304. At this time, each time the process proceeds to ST304, the warning process (display by the display unit 20c, sound by the speaker 20d indicating completion of filling) is restarted, and timer monitoring based on the waiting time Tb is repeated. Thereafter, the warning process in ST304 is repeated any number of times until the switching operation valve 23 is switched to the standby state. During this time, the timer monitoring of the power auto-off function is also performed, but since the waiting time Tw of the power auto-off function is set sufficiently longer than the waiting time Tb, the waiting time Tb times out before the waiting time Tw has elapsed, and the warning process is repeated. Therefore, while the switching operation valve 23 is not switched to the standby state in ST302, the power will not be turned off by the power auto-off function. Then, when the operator switches the switching valve 23 to the standby state, the process proceeds to ST305.

[0075] (ST305) Next, the control parameters required for control are confirmed and changed using the input operation button 19b. Specifically, a set pressure P1, which is a target air pressure to be filled, is set according to the size and type of the tire to be filled with air. In addition, other control parameters such as the filling start pressure P0, the tire connection confirmation pressure P2, the sampling time Ts of the pressure sensor 26, the waiting time Tw until the power auto-off function is activated, the waiting time Tb for warning processing, etc., and the waiting time Ta from the ON signal of the microswitch 66 are also reset if they are to be changed from the initial setting values ​​(or the previous setting values) input and saved in advance. Here, the set pressure P1 is set to 250 kPa, the filling start pressure P0 is set to 30 kPa, the tire connection confirmation pressure P2 is set to 700 kPa, the sampling time Ts is set to 2 seconds, the waiting time Tw is set to 10 minutes, the waiting time Tb is set to 1 minute, and the waiting time Ta is set to 3 seconds.

[0076] (ST306) Next, the tire to be filled with air is connected to air chucks 15a to 15d. The number of tires to be connected may be 1 to 4, but in this example, one tire is connected to air chuck 15a and filled with air. Next, proceed to ST307.

[0077] (ST307) The cylinder 52 of the switching operation valve 23 is slid to the "upper position" to open it. As a result, if positive air pressure remains in the connected tire, the remaining air from the tire flows into the control manifold 21, resulting in a positive pressure (P>0). On the other hand, if there is no positive air pressure remaining in the tire (P=0), atmospheric pressure is maintained in the air flow path 12b to the control manifold 21 if the initial state A is selected in ST300. Also, if the initial state B is selected in ST300, the remaining air that was left from the branching manifold 13 to the air chucks 15a to 15d during the previous air filling is diffused into the flow path from the control manifold 21 to the tire, and as a result, the pressure measured by the pressure sensor 26 becomes slightly more positive than atmospheric pressure (P>0). Furthermore, when the cylinder 52 comes into contact with the microswitch 66, an ON signal is sent from the microswitch 66 to the control unit 20, and timer monitoring based on the waiting time Ta is started. Then, the process proceeds to ST308.

[0078] (ST308) After the switching valve 23 is switched to the open state, the first pressure measurement is performed by the pressure sensor 26. This measured pressure P is compared with the filling start pressure P0 to check for tire abnormalities such as a puncture. If P≦P0, proceed to ST309, and if P>P0, proceed to ST314.

[0079] (ST309) If P≦P0 in ST308 (because the remaining air pressure in the tire has dropped too much), it is determined that there is a possibility of a tire abnormality, and the automatic on-off valve 24 is maintained in the closed state. Then, timer monitoring is performed to measure whether the elapsed time T from when the microswitch 66 sent an ON signal (i.e., when the switching operation valve 23 was opened) exceeds the waiting time Ta, and if T≦Ta, the process returns to ST308 and repeats the process flow up to S309. While this processing flow is being repeated, if the pressure measured by the pressure sensor 26 in ST308 becomes P>P0, the process proceeds to ST314. However, while P≦P0 continues, the comparison of the elapsed time T with the waiting time Ta is repeated, and when T>Ta (without P>P0) occurs, the process proceeds to ST310.

[0080] (ST310) In ST309, since the measured pressure P did not exceed P0 until the elapsed time T exceeded the waiting time Ta, a warning process (warning display, warning sound) is performed to warn the operator that the remaining air pressure has dropped too low, prompting them to check for safety. Then, timer monitoring of the warning process using the waiting time Tb is started. Except in cases where the cause of the drop in remaining air pressure is clear, the operator performs safety check work to check for tire abnormalities such as punctures, poor connections in the air flow path, and other abnormalities. Then, proceed to ST311.

[0081] (ST311) If no abnormality is found as a result of the safety check work, or if the cause of the abnormality is eliminated and safety is confirmed, the air filling work can be continued, so as an exception, the filling button 19c for manually opening the automatic opening / closing valve 24 is turned ON, and the process proceeds to ST314. In ST311, if the fill button 19c is not turned ON for a while due to a safety confirmation operation or the like, the process proceeds to ST312 to continue timer monitoring for warning processing.

[0082] (ST312) If the fill button 19c is not turned ON in ST311, timer monitoring continues with a waiting time Tb, and the elapsed time T from the warning processing in ST310 is measured, and while T≦Tb, the process returns to ST311 and repeats the process flow up to ST312. If the fill button 19c is turned ON in ST311 while this process flow is being repeated, the process proceeds to ST314, but if T>Tb occurs without the button being turned ON, the process proceeds to ST313.

[0083] (ST313) If T>Tb without the refill button 19c being turned ON, a warning process (display on the display unit 20c, sound from the speaker 20d) is performed to prompt the operator to turn on the refill button 19c. Then, the process returns to ST311 and repeats the process flow up to ST313. At this time, the warning process is restarted each time the process proceeds to ST313, and timer monitoring based on the waiting time Tb is repeated. Thereafter, the warning process in ST313 is repeated any number of times until the refill button 19c is turned ON in ST311. During this time, the timer monitoring of the power auto-off function is also performed, but since the waiting time Tw of the power auto-off function is set sufficiently longer than the waiting time Tb, the waiting time Tb times out before the waiting time Tw has elapsed, and the warning process is repeated. Therefore, the power will not be turned off by the power auto-off function until the fill button 19c is turned ON in ST311. When the operator turns on the fill button 19c, the process proceeds to ST314.

[0084] (ST314) By opening the automatic on-off valve 24 by automatic control by the control unit 20 (ST308) or by an ON signal (ST311) by manually operating the filling button 19c, high-pressure air is fed from the air supply source 11 to the downstream side, filling the tire with air, and the pressure values ​​in the tire and the air flow path increase. Next, the process proceeds to ST315.

[0085] (ST315) When high-pressure air from the air supply source 11 is fed downstream of the automatic on-off valve 24, the pressure value in the control manifold 21 rises, and the pressure sensor 26 detects this. At this time, when the tire is connected to the air chuck 15a and when the tire is not connected (because ST306 was not executed correctly by mistake), the total volume downstream of the automatic on-off valve 24 (the total volume of the connected tire and the air flow path) is significantly different. When the tire is not connected, the pressure in the air flow path rises significantly during one sampling time Ts compared to when the tire is connected. That is, the pressure value in the control manifold 21 (and in the air flow path) greatly exceeds the set pressure P1 before the first (or about the second) sampling time Ts of the pressure sensor 26 elapses, and the pressure rises all at once until it exceeds the tire connection confirmation pressure P2. On the other hand, when the tire is connected, since the total volume of the tire and the air flow path is large, the pressure rise during one sampling time Ts is mitigated. Even if it exceeds the set pressure P1, the automatic on-off valve 24 is closed and the automatic discharge valve 25 performs pressure reduction adjustment to the set pressure P1 before reaching the tire connection confirmation pressure P2 set sufficiently large, so it will never exceed the tire connection confirmation pressure P2. Therefore, by setting the upper limit pressure value of a value sufficiently larger than the set pressure P1 as the tire connection confirmation pressure P2, preferably by further adjusting the sampling time Ts, it becomes possible to confirm the connection between the air chucks 15a to 15d and the tire using the tire connection confirmation pressure P2. That is, when the measured pressure P and the tire connection confirmation pressure P2 satisfy P≧P2, the process proceeds to ST401, and when P<P2, the process proceeds to ST316.

[0086] (ST316) The pressure sensor 26 detects the current pressure value every sampling time Ts, and performs a process to bring the tire air pressure closer to the set pressure P1 by comparing the measured pressure P with the set pressure P1. That is, when P < P1, the automatic on-off valve 24 is opened (or maintained in the open state) and the pressure filling is continued. When P > P1, since the set pressure P1 is exceeded, the process proceeds to ST317 to perform a pressure reduction process (or maintain the pressure reduction process). When P = P1, the process proceeds to ST318 to maintain the current air pressure.

[0087] (ST317) Since the measured pressure P exceeds the set pressure P1, the automatic on-off valve 24 is closed and the automatic discharge valve 25 is opened to perform a pressure reduction process of discharging a part of the filled air until the next sampling time Ts arrives. Subsequently, the process returns to ST316 and the process is repeated.

[0088] (ST318) Since the measured pressure P is equal to the set pressure P1, the automatic on-off valve 24 is closed and the automatic discharge valve 25 is closed to perform a process of maintaining the current air pressure. Also, a completion process (filling completion display by the display unit 20c, sounding of the filling completion sound by the speaker 20d) notifying that the measured pressure P is equal to the set pressure P1 is performed. Thereby, the operator is urged to remove the filled tire, and at the same time, the switching operation valve 23 is urged to be switched to the standby state for preparing to continue air filling to another tire. Further, the timer monitoring of the completion process by the waiting time Tb starts. Subsequently, the process proceeds to ST319.

[0089] (ST319) While the switching operation valve 23 remains in the open state, air of about the set pressure P1 (i.e., the measured pressure P > P0) remains in the control manifold 21. However, when the switching operation valve 23 is switched to the standby state by the operator, the pressure in the control manifold 21 becomes the atmospheric pressure state (0 kPa). When it is detected by the pressure sensor 26 that the measured pressure P is in the atmospheric pressure state (i.e., P ≤ P0), it is determined that the switching operation valve 23 has been switched to the standby state, and the process proceeds to ST321. On the other hand, when the measured pressure P of the pressure sensor 26 is P > P0, it is determined that the valve has not yet been switched from the open state, and the process proceeds to ST320 to continue the timer monitoring of the waiting time Tb.

[0090] (ST320) While the switching operation valve 23 remains in the open state (i.e., when P > P0), the timer monitoring of the completion process started in ST318 continues. That is, the elapsed time T from the previous ST318 and the waiting time Tb are compared. When T < Tb, the process returns to ST319 and repeats the processing flow up to ST320. When the elapsed time T during which this processing flow is repeated becomes T > Tb, the process returns to ST316 and repeats the processing flow up to ST320. At this time, each time the process proceeds to ST318, the completion process (filling completion display by the display unit 20c and sounding of the filling completion sound by the speaker 20d) restarts, and the timer monitoring based on the waiting time Tb is repeated. Thereafter, the completion process at ST113 is repeated any number of times until the switching operation valve 23 is switched to the standby state. During this period, the timer monitoring of the power auto-off function is also being performed. However, since the waiting time Tw of the power auto-off function is set to be sufficiently longer than the waiting time Tb of the completion process, the waiting time Tb times out first and the completion process is repeated before the waiting time Tw elapses. Therefore, until the switching operation valve 23 is switched to the standby state at ST114, the power will not be turned off by the power auto-off function. When the switching operation valve 23 is switched to the standby state by the operator, the process proceeds to ST321.

[0091] (ST321) When the switching valve 23 is switched to the standby state, the air flow path returns to the initial state B. The filled tire is removed from the air chuck 15a and the air filling operation is completed. If another tire is to be filled next, the tire is connected. When the filling operation is to be completed, the dummy valve 32 is reset to return to the initial state A and the power is manually turned off.

[0092] (ST322) While the power is not manually turned off in ST321, timer monitoring continues based on the waiting time Tw. That is, when none of the operation buttons are operated, no warning processing is performed, and the pressure signal value of the pressure sensor 26 measured at each sampling time Ts is not fluctuating (processing is not progressing), the timer monitoring processing flow in ST322 is repeated. Then, the elapsed time T while this processing flow is being repeated is measured and compared with the waiting time Tw, and while T≦Tw continues, the process returns to ST322 to repeat the processing flow, and when T>Tw, the process proceeds to ST323.

[0093] (ST323) Since the waiting time Tw has elapsed, the automatic power off process is performed. That is, a sound is generated by the speaker 20d to inform the user that the power will be turned off, and the power is automatically turned off after a delay of 1 to 2 minutes after the sound is generated.

[0094] (ST401) If the measured pressure P is equal to or greater than the tire connection confirmation pressure P2 in ST315, it is determined that the tire is not connected, and a warning process for the pressure rise is performed (the display unit 20c displays the pressure rise, and the speaker 20d issues a sound to notify the user of the pressure rise). The automatic on-off valve 24 is closed and the automatic exhaust valve 25 is opened by the control unit 20, whereby the pressure inside the air flow path (from the control manifold 21 to the air flow paths 14a to 14d) is reduced so that it approaches atmospheric pressure (0 kPa). As the pressure reduction progresses, the pressure sensor 24 detects that the measured pressure P has fallen below the filling start pressure P0. The process then proceeds to ST402.

[0095] (ST402) When the pressure sensor 26 detects that P < P0, the control unit 20 switches the automatic discharge valve 25 to the closed state (while the automatic on-off valve 24 remains closed). In this embodiment, from the time when the pressure sensor 24 detects less than P0, a sufficient time delay is provided until the air passage completely returns to the atmospheric pressure state (0 kPa) and stops changing (for example, 10 seconds), and then the automatic discharge valve 25 is closed. After the automatic discharge valve 25 is closed, an operation instruction process (operation instruction by the display unit 20c and the speaker 20d) is performed to prompt the confirmation operation that the tire is not connected and the operation of switching the switching operation valve 23 from the open state to the standby state, and waits for the operator to execute the process. Subsequently, the process proceeds to ST403.

[0096] (ST403) The operator checks the connection status with the tire by receiving the operation instructions from the display unit 20b and the speaker 20c in ST402. Also, by switching the switching operation valve 23 to the standby state, the upstream side of the switching operation valve 23 becomes the atmospheric pressure state, and the downstream side also becomes the atmospheric pressure state, returning to the initial state A. Subsequently, the process proceeds to ST404.

[0097] (ST404) Connect the tire to the air chuck and perform a safety check. If there is no problem, return to ST307 (or ST300) and redo the filling operation. Through the above processing flow, even in an air filling device using a closed-type air chuck, the tire connection state can be confirmed and the filling operation can be performed safely. Note that the power auto-off function also operates in ST403. If the switching operation valve 23 cannot be switched to the standby state by the operator and the waiting time Tw elapses, the power will automatically turn off. After that, when restarting the filling operation, start from ST300. Through the above processing flow, even in an air filling device using a closed-type air chuck, the tire connection state can be confirmed and the filling operation can be performed safely.

[0098] Thus, according to the present invention, a pressure reducing valve is not disposed in the air flow path, and air can be filled up to the target filling pressure by automatic control by the control unit 20, so air can be filled quickly and without hassle. Also, since a closed type air chuck is connected, one tire or up to the same number of tires as the air chuck can be connected and filled with air simultaneously, and even if a tire is removed from the air chuck after air filling is complete, the air filled in other tires will not flow back and be released to the outside, so air can be reliably filled up to the target filling pressure. Also, by checking whether the pressure rises rapidly to tire connection confirmation pressure P2, which is higher than set pressure P1, immediately after air filling starts, it is possible to reliably determine whether the tire is connected or not. This prevents erroneous operation when the tire is not connected, and allows air filling to be done safely.

[0099] Although the representative examples of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and can be modified or changed as appropriate within the scope of the claims, while achieving the object of the present invention. For example, although the above embodiment uses the switching valve 23 which is a mechanical valve, an electromagnetic three-way valve 23a may also be used. FIG. 9 is an external view of an air filling device M'' which uses an electromagnetic three-way valve 23a. The same components as in FIG. 1 are given the same reference numerals and will not be described. In this embodiment, the switching operation between the open state and the standby state is performed by a switching button 19e provided on the control panel of the control unit 20. In the case of the electromagnetic three-way valve 23a, an ON signal from the switching button 19e can be sent to the control unit 20 in place of the ON signal from the microswitch 66 in FIG. 6. [Industrial Applicability]

[0100] INDUSTRIAL APPLICABILITY The present invention can be used in an air filling device that fills a plurality of tires with air at the same time. [Explanation of symbols]

[0101] 11 Air supply source 12a, 12b Air flow path 13 Branch manifold 14a-14d Branch flow path 15a~15d Air chuck 20 Control section 20a Storage section 20b Input section 20c Display section 20d Speaker 21 Control manifold 22 Automatic filling section 23 Switching valve 24 Automatic shut-off valve 25 Automatic drain valve 26 Pressure Sensor 51 Body 52 cylinders 57 Sealing Block 58 Upper hole 59 Pilot hole 65 Cylinder space 66 Microswitch P0 Filling start pressure P1 set pressure P2 Connection check pressure Tw Power Auto-Off function wait time Ta Waiting time for warning processing, etc. Tb Waiting time to start with ON signal of microswitch 66 Ts Sampling time

Claims

1. An air filling device in which a plurality of branch flow paths are connected in parallel to an air flow path connected to an air supply source via a branching manifold, a closed-type air chuck is connected to an end of each of the branch flow paths, and at least one tire is connected to one of the air chucks to fill the tire with air, An automatic filling unit controlled by a control unit is provided in the air flow path, and a switching valve is provided between the automatic filling unit and the branching manifold, the automatic filling unit includes an automatic on-off valve that opens and closes the air flow path between the air supply source and the automatic filling unit, an automatic exhaust valve that opens the air flow path downstream of the automatic on-off valve to the atmosphere, and a pressure sensor that detects pressure at each predetermined sampling time, The switching operation valve is configured to be switched between an open state in which the upstream side and the downstream side are connected, and a standby state in which the upstream side is opened to the atmosphere and the downstream side is closed, the control unit includes a storage unit that stores a set pressure P1 that determines a filling pressure for the tire, a filling start pressure P0 that is a pressure value smaller than the set pressure P1 and determines a lower limit pressure value for automatically starting air filling, and a tire connection confirmation pressure P2 that is a pressure value larger than the set pressure P1 and that confirms the connection state of the tire; This air filling device is characterized by starting air filling based on the filling start pressure P0, then checking the connection state between the tire and the air chuck based on the tire connection confirmation pressure P2, and automatically controlling to approach the filling pressure based on the set pressure P1.

2. The switching operation valve has a straight tube body and a hollow cylindrical cylinder having a cylindrical side wall, an upper wall, and a lower wall; the cylinder has an upper wall and a lower wall formed with a through hole into which the body can be inserted, the cylinder is attached coaxially to an outer circumferential surface of the body in an airtight manner and vertically slidable manner, and a cylinder internal space is formed between the cylinder and the outer circumferential surface of the body; The body is provided with a sealing block that divides the inside of the straight pipe into an upper space and a lower space, and an upper hole is formed in the upper pipe wall near the sealing block, and a lower hole is formed in the lower pipe wall near the sealing block. When the cylinder is slid to the upper position, the upper hole and the lower hole are included in the cylinder internal space 65, 2. The air filling device according to claim 1, wherein when the cylinder is slid to a lower position, the upper hole is opened to the atmosphere and the lower hole is closed by the space within the cylinder.

3. 2. The air filling device according to claim 1, wherein said switching valve is a three-way valve.

4. The device is provided with at least one of a display unit capable of displaying a warning and a speaker capable of sounding a warning sound; The switching valve is provided with a switch that generates an ON signal when the switching valve is open. The storage unit stores a waiting time Ta measured when the switching valve is in an open state, 2. The air filling device according to claim 1, wherein said control unit displays or sounds a warning when the pressure value measured by said pressure sensor does not exceed P0 until said waiting time Ta has elapsed since said switch generated an ON signal.

5. 2. The air filling device according to claim 1, wherein the filling start pressure P0 is set to a pressure value equal to or higher than 20 kPa and lower than a set pressure P1.

6. 2. The air filling device according to claim 1, wherein the tire connection confirmation pressure P2 is set at a pressure value of 500 to 1200 kPa.

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