JP4779905B2 - Tire pressure control device - Google Patents

Description

  The present invention relates to a tire pressure control device including a pair of left and right air pump devices that are provided corresponding to left and right wheels of a vehicle and generate pressurized air supplied to tire air chambers of the wheels.

As one of the tire pressure control devices of this type, each wheel is driven as a pump by rotation of each wheel until the tire pressure of each wheel decreases to the lower limit set value and increases to the upper limit set value. generating the pressurized air supplied to the tire air chamber, and, until the tire pressure of each wheel is reduced to the lower limit set value from the rising to the upper limit set value, the driving of the pump by the rotation of each wheel Is provided with an air pump device that stops the generation of pressurized air, for example, as shown in Patent Document 1 below.
JP 2005-515923 A

In the tire air pressure control device described in Patent Document 1 described above, each air pump device rotates each wheel until the tire air pressure of each wheel decreases to the lower limit set value and increases to the upper limit set value. As a pump , the pressurized air is sent to the tire air chamber of each wheel, thereby increasing the tire air pressure of each wheel. Also, during the period from when the tire air pressure of each wheel rises to the upper limit set value and until it drops to the lower limit set value, the drive as a pump by the rotation of each wheel of each air pump device is stopped, and the pressurized air is It is not sent to the tire air chamber of each wheel.

By the way, when the tire pressure control device described in Patent Document 1 described above is provided corresponding to left and right wheels (left and right front wheels or left and right rear wheels) of a vehicle such as a four-wheeled vehicle, the tire pressure control devices are provided respectively on the left and right wheels. When the air pump devices are not driven simultaneously, a difference occurs in rotational resistance (load generated by driving the air pump device as a pump ) acting on the left and right wheels, and the vehicle may be deflected in the left-right direction.

The present invention has been made to cope with the above-described problem (deflection of the vehicle in the left-right direction), and the tire pressure control device is provided corresponding to each of the left and right wheels of the vehicle. tire air pressure generates the pressurized air supplied to the tire air chamber of the drive has been each wheel as a pump by the rotation of the wheels until rising to the upper limit set value from the lowered to the lower limit set value of, and A pair of left and right air that stops generating pumped air by stopping the driving of the pump by the rotation of each wheel during the period from when the tire air pressure of each wheel rises to the upper limit set value and to the lower limit set value a pump device, when the tire air pressure of the right and left wheels are different, the timing at which the tire air pressure by exhausting air under reduced pressure from the higher side of the tire air chamber, the tire pressure of each wheel is reduced to the lower limit set value same By, it is characterized in that it comprises a pressure reducing means as synchronizing means for synchronizing the generation start timing of the pressurized air by the both air pump device.

In the tire pressure control device according to the present invention, as a synchronizing means for synchronizing the generation start timing of the pressurized air by the pair of left and right air pump devices , when the tire pressures of the left and right wheels are different, the tire air chamber on the higher tire pressure side It is equipped with pressure reducing means that synchronizes the timing when the tire air pressure of the left and right wheels decreases to the lower limit set value by discharging air from the vehicle, so that the initial load (driving start) generated by driving each air pump device as a pump Load at the same time, eliminating the difference in rotational resistance acting on the left and right wheels at the start of driving each air pump device provided corresponding to the left and right wheels. It is possible to eliminate the deflection.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a four-wheeled vehicle equipped with a tire pressure control device according to the present invention. As shown in FIG. 1, the tire pressure control device according to the present invention corresponds to a pair of left and right air pressure generation units FLA and FRA provided corresponding to the left and right front wheels FL and FR, and left and right rear wheels RL and RR, respectively. Are provided with a pair of left and right air pressure generation units RLA, RRA, and pressure reducing valves VBfl, VBfr, VBrl, VBrr incorporated in each air pressure generation unit FLA, FRA, RLA, RRA.

  Each of the air pressure generation units FLA, FRA, RLA, and RRA has one wheel (air pressure generation unit FRA attached to the right front wheel FR) as an example, as shown in FIGS. An air pump AP that can be driven by rotation of RL and RR and can generate pressurized air supplied to the tire air chamber Rb of each wheel FL, FR, RL, and RR, and the tire air chamber Rb and the air pump AP are connected. An air pump device provided with a control valve device VA that is interposed in a pneumatic circuit that controls communication between the tire air chamber Rb, the air pump AP, and the atmosphere, and is a tire for each wheel FL, FR, RL, RR The air pressure can be maintained between the lower limit set value P1 and the upper limit set value P2 (P1 <P2).

  The tire air chamber Rb of each wheel FL, FR, RL, RR is formed by the wheel B1 and the tire B2 as shown in FIG. 2 as an example of the wheel FR, and the tire air pressure of the tire air chamber Rb is inside. A pressure sensor S1fr for detecting (Pfr) is provided. Signals output from the pressure sensor S1fr provided on the wheel FR and the pressure sensors S1fl, S1rl, S1rr provided on the other wheels (the tire air pressures Pfl, Pfr, Prl, Prr at each wheel FL, FR, RL, RR) Are equivalently input to the electric control unit ECU shown in FIG. 4 wirelessly.

  As shown in FIGS. 2 and 3, the air pump AP and the control valve device VA are assembled to an axle hub 11 that rotates together with the wheels FR, and a drive axle 12 is splined at the vehicle inner end of the axle hub 11. It is fitted and connected so that torque can be transmitted. The connection between the axle hub 11 and the drive axle 12 is fixed by a lock nut 13.

  The air pump AP (sometimes referred to as an air compressor) generates compressed air by adiabatically compressing the atmosphere. The air pump AP is driven as the wheel FR rotates and is driven as the wheel FR stops rotating. The cylinder member 21 is configured to be stopped, and can supply pressurized air to the tire air chamber Rb of the wheel FR through the pressure control valve 30 based on the rotation of the wheel FR. In addition to a rotatable cylinder 22 formed in the shaft portion 11a and a piston 23 as a reciprocating body, a cam member 24 and a pair of cam followers 25 are provided.

  The cylindrical member 21 is non-rotatably supported by a support member (not shown), and the cylinder 22 is rotated inside the wheel FR via a pair of bearings Br1 and Br2 and a pair of annular seal members 26 and 27. It can be rotated around the center and is liquid-tightly supported. The pair of bearings Br1 and Br2 are disposed apart from each other by a predetermined amount in the axial direction, and are interposed between the cylindrical member 21 and the cylinder 22 so as to sandwich the cam member 24 in the axial direction. Can be rotated. The pair of annular seal members 26 and 27 are disposed apart from each other by a predetermined amount in the axial direction, and are interposed between the cylindrical member 21 and the cylinder 22 so as to sandwich the cam member 24 and both bearings Br1 and Br2 in the axial direction. In addition, the space between the cylindrical member 21 and the cylinder 22 is liquid-tightly sealed.

  The cylinder 22 includes a cylinder main body 22A and a cylinder head 22B screwed to the outer end of the cylinder main body 22A so as to be airtight and detachable. The cylinder body 22A is formed integrally with the shaft portion 11a of the axle hub 11, and has a pair of axial long holes 22a and a cylinder inner hole 22b extending in the cylinder axial direction. The cylinder head 22B is a bottomed cylindrical plug member that is airtightly and detachably assembled to the axle hub 11. The cylinder head 22B includes a suction / discharge passage 22c and a discharge passage 22d, and includes a pressure guide passage 22e and a suction passage 22f. Have.

  The pair of axially elongated holes 22a are guide means for guiding the piston 23 and each cam follower 25 so as to be able to rotate integrally with the cylinder 22 and reciprocate in the axial direction of the piston, and are spaced 180 degrees apart in the circumferential direction of the cylinder 22. Is formed. The cylinder inner hole 22b accommodates the piston 23, the outer end of the vehicle is closed by the cylinder head 22B, and the cylinder head 22B and the piston 23 form a pump chamber Ro.

  The suction / discharge passage 22c is always in communication with a communication passage 31a provided in the valve body 31 of the pressure control valve 30, and is a suction check valve Vi (an annular seal member having a V-shaped cross section) assembled to the cylinder head 22B. It is possible to introduce air into the pump chamber Ro through the discharge check valve Vo (configured with an annular seal member having a V-shaped cross section) assembled to the valve body 31 of the pressure control valve 30. The air can be led out from the pump chamber Ro.

  The discharge passage 22d is a passage for guiding the pressurized air discharged to the air chamber Ra1 through the discharge check valve Vo to the discharge passage 11b provided in the axle hub 11, and includes a radial communication hole 22d1 provided in the cylinder head 22B, It is constituted by a communication groove 22d2 provided on the outer periphery of the cylinder head 22B. The discharge passage 11b provided in the axle hub 11 communicates with the tire air chamber Rb through the communication passage Ba provided in the wheel FR as shown in FIG.

  The pressure guide passage 22e is a communication hole in the cylinder radial direction provided in the cylinder head 22B, and the pressurized air in the discharge passage 22d is formed in the air chamber Ra2 formed between the valve body 31 and the stopper 32 of the pressure control valve 30. Can be introduced. The suction passage 22f is always in communication with the atmosphere communication passage 31b provided in the valve body 31 of the pressure control valve 30, and can be communicated / blocked with respect to the communication passage 31a provided in the valve body 31 of the pressure control valve 30. . Note that the atmosphere communication passage 31b provided in the valve body 31 is always in communication with the atmosphere through the atmosphere communication passage 42b formed in the adjustment screw 42 of the adjustment device 40.

  The piston 23 is inserted into a cylinder inner hole 22b of the cylinder 22 via a pair of annular seal members 28, 29, and is assembled so as to be able to rotate integrally with the cylinder 22 and to reciprocate in the piston axial direction. . The piston 23 has an annular groove 23a and a through hole 23b extending in the piston radial direction. The pair of annular seal members 28 and 29 are disposed apart from each other by a predetermined amount in the axial direction, and are interposed between the piston 23 and the cylinder 22 at the axial end portion of the piston 23, and between the piston 23 and the cylinder 22. Is hermetically and liquid tightly sealed.

  The annular groove 23 a is formed on the outer periphery of the piston 23 between the pair of annular seal members 28 and 29, and forms an annular space R 1 between the cylinders 22. The annular space R <b> 1 communicates with an annular space R <b> 2 formed between the pair of annular seal members 26 and 27 through the axial long holes 22 a of the cylinder 22. Each annular space R1, R2 has a volume that does not change even if the piston 23 reciprocates in the piston axial direction, and is sealed by four seal members 26, 27, 28, 29. The annular spaces R1, R2 and the like are oil chambers for storing a required amount of lubricating oil. The oil chambers contain bearings Br1, Br2, a cam member 24, a cam follower 25, a compression coil spring Sp, and the like. ing.

  The cam member 24 is constituted by a pair of cam sleeves 24A and 24B connected in the piston axial direction, and is provided integrally with the cylindrical member 21 (not axially movable and non-rotatable). Are arranged coaxially. The cam member 24 has an annular cam portion 24a that varies in the axial direction. The cam portion 24a is a cam groove, and a ball 25c of each cam follower 25 is engaged therewith. The cam portion 24a has a cam surface that receives a load in the piston axial direction (a load in the horizontal direction in the drawing) and a load in the piston radial direction (a load in the vertical direction in the drawing) from the ball 25c of each cam follower 25. Has a V-shaped cross section, and is formed in an even number of cycles (for example, two cycles) in the circumferential direction of the cylinder 22.

  Each cam follower 25 is constituted by a shaft 25a divided into two in the piston 23, and a roller 25b and a ball 25c assembled to each of the shafts 25a, and the piston 25 is inserted into the through hole 23b of the piston 23 by the shaft 25a. 23 is movably provided in the radial direction. Each cam follower 25 is engaged with a cam portion (cam groove) 24a of the cam member 24 by an end portion extending in the piston radial direction, that is, a ball 25c, and rotates relative to the cam member 24. This moves in the direction of the piston axis.

  Each shaft 25a is a load transmission element assembled to the through hole 23b of the piston 23 so as to be movable in the radial direction of the piston 23 (the axial direction of the through hole 23b), and a compression coil spring Sp interposed therein. Is urged outward of the diameter of the piston 23. Each shaft 25a is a support that rotatably supports the roller 25b, and rotatably supports the roller 25b at a small-diameter end protruding from the through hole 23b of the piston 23.

  Each roller 25b is rotatably fitted in the axial long hole 22a of the cylinder 22 in a state where the roller 25b is rotatably fitted to the small diameter end portion of the shaft 25a, and the cam follower 25 moves in the cylinder axial direction. It is possible to roll along the axial long hole 22a of the cylinder 22. Each roller 25b has a hemispherical concave receiving portion at the outer end, and supports the ball 25c so that it can roll.

  Each ball 25c is a convex portion of the cam follower 25 that is supported by the roller 25b so as to be able to roll and engages with a cam portion (cam groove) 24a of the cam member 24 so as to roll. The shaft 25a and the roller 25b are connected to each other. In response to the elastic force of the compression coil spring Sp, it is elastically engaged with the cam portion (cam groove) 24a of the cam member 24 without any gap.

  The compression coil spring Sp is a pressing means that presses the ball 25c of each cam follower 25 toward the cam portion (cam groove) 24a of the cam member 24 in the radial direction of the piston 23, and is provided on the shaft 25a of each cam follower 25. It is assembled in a state where a predetermined preliminary load is applied to the bottomed mounting hole.

  In this air pump AP, when the cylinder 22 (axle hub 11) rotates while the valve element 31 of the pressure control valve 30 is held at the position shown in FIGS. 2 and 3, the piston 23 and the cam follower 25 are connected to the cylinder 22. And rotate relative to the cam member 24 to move in the axial direction. Therefore, the rotational motion of the cylinder 22 can be converted into the reciprocating motion of the piston 23, and the volume of the pump chamber Ro can be increased or decreased by the reciprocating motion of the piston 23. Air is sucked into the pump chamber Ro through the passage 31b, the suction passage 22f, the suction check valve Vi, the communication passage 31a, and the suction / discharge passage 22c, and from the pump chamber Ro through the suction / discharge passage 22c, the communication passage 31a, and the discharge check valve Vo. It is possible to discharge air.

  The control valve device VA is a mechanical control valve device that operates according to the tire air pressure in the tire air chamber Rb. The control valve device VA includes a pressure control valve 30 and an adjustment device 40, and is coaxial with the pressure control valve 30. The relief valve 50 arranged is provided and is coaxially arranged on the shaft portion (rotating shaft) 11a of the axle hub 11 together with the air pump AP.

  The pressure control valve 30 is assembled in the cylinder head 22B, and includes a valve body 31 and a stopper 32. The pressure control valve 30 is engaged with the valve body 31 via a spring retainer 33. A compression coil spring 34 whose position can be controlled and whose urging force (spring force) to the valve body 31 can be adjusted by the adjusting device 40 is provided. The pressure control valve 30 is activated when the tire air pressure (Pfr) of the tire air chamber Rb is lowered to the lower limit set value P1 (the valve body 31 is moved from the illustrated position against the urging force of the compression coil springs 34 and 52). From the pump chamber Ro to the tire air chamber Rb, the pressurized air supplied from the pump chamber Ro to the tire air chamber Rb can be switched. When the upper limit set value P2 is raised, the state is switched from the illustrated state to the operating state, and the supply of pressurized air from the pump chamber Ro to the tire air chamber Rb can be limited (stopped).

  The valve body 31 is assembled in the cylinder head 22B so as to be airtight and movable in the cylinder axial direction via a discharge check valve Vo and an annular seal member 35 assembled on the outer periphery. An air chamber Ra1 communicating with the discharge passage 22d is formed therebetween, and an air chamber Ra2 communicating with the stopper 32 through the pressure guide passage 22e is formed between the air passage Ra1 and the stopper 32. The stopper 32 is assembled with an annular seal member 36 on the inner periphery and an annular seal member 37 on the outer periphery, and is hermetically interposed between the cylinder head 22B and the valve body 31. The outer periphery of the vehicle is integrally screwed to the cylinder head 22B at the outer end of the vehicle.

  The air chamber Ra1 is always in communication with the tire air chamber Rb through the discharge passage 22d, the discharge passage 11b, and the communication passage Ba. The air chamber Ra2 is always in communication with the tire air chamber Rb through the pressure guiding passage 22e, the discharge passage 22d, the discharge passage 11b, and the communication passage Ba. The pressure receiving area of the valve body 31 exposed to the air chamber Ra1 is set to be a predetermined amount larger than the pressure receiving area of the valve body 31 exposed to the air chamber Ra2.

  In the pressure control valve 30, the valve body 31 is held at the illustrated position when the tire air pressure (Pfr) of the tire air chamber Rb decreases from the lower limit set value P1 to the upper limit set value P2. Thus, the communication between the communication passage 31a and the suction passage 22f is blocked by the suction check valve Vi. Therefore, the suction check valve Vi allows the air flow from the atmosphere to the pump chamber Ro, and the discharge check valve Vo allows the air flow from the pump chamber Ro to the tire air chamber Rb (the state shown in the drawing). The check valve Vi blocks communication between the communication passage 31a and the suction passage 22f to restrict the air flow from the pump chamber Ro to the atmosphere, and the discharge check valve Vo controls the air flow from the tire air chamber Rb to the pump chamber Ro. regulate.

Therefore, in this state (the permissible state in which the pressure control valve 30 allows the supply of pressurized air from the air pump AP to the tire air chamber Rb), the air is pumped into the pump chamber by the reciprocation of the piston 23 accompanying the rotation of the wheel FR. While being sucked into Ro, pressurized air is discharged from the pump chamber Ro toward the tire air chamber Rb. This state is a state in which the air pump AP generates pressurized air in cooperation with the control valve device VA (drive state of the air pressure generation unit FRA), and is an air pump that is driven as a pump by the rotation of the wheels FR. A load (rotational resistance acting on the wheel FR) generated by driving the AP is large.

  Further, in this pressure control valve 30, when the air pressure (Pfr) of the tire air chamber Rb rises to the upper limit set value P2 and decreases to the lower limit set value P1, the valve element 31 is compressed by the compression coil spring 34, 52 is moved in the axial direction by a predetermined amount from the illustrated position against the urging force of 52, and the communication passage 31a communicates with the suction passage 22f regardless of the suction check valve Vi. For this reason, the suction check valve Vi has lost its function (backflow prevention function), the communication passage 31a communicates with the suction passage 22f to allow the air flow between the pump chamber Ro and the atmosphere, and the discharge check valve. Vo regulates the air flow between the discharge passage 22d and the communication passage 31a, that is, between the pump chamber Ro and the tire air chamber Rb. When the valve body 31 is moved by a predetermined amount from the illustrated position against the urging force of the compression coil springs 34 and 52 (operating state), the stepped portion of the valve body 31 is attached to the inner periphery of the stopper 32. This is in contact with the seal member 36.

Therefore, in this state (the prohibited state in which the pressure control valve 30 prohibits the supply of pressurized air from the air pump AP to the tire air chamber Rb), even if the piston 23 reciprocates as the wheel FR rotates, the pump The air sucked into the chamber Ro is not pushed back toward the atmosphere and discharged from the pump chamber Ro toward the tire air chamber Rb. This state is a state in which the air pump AP does not generate pressurized air (the non-driven state of the air pressure generating unit FRA), and the air pump AP in a state where driving as a pump is stopped by rotation of the wheel FR is driven. The load caused by this (rotational resistance acting on the wheel FR) is small.

  The adjusting device 40 can adjust the position of the spring support 41 that supports the other end of the compression coil spring 34 in the pressure control valve 30 (the fixed end that does not move when the valve body 31 moves), and the position of the spring support 41. An adjustment screw 42 is provided. The spring support 41 is movable along with the movement of the adjustment screw 42, and is rotatably engaged with the adjustment screw 42 by a hemispherical convex portion 41a.

  The adjustment screw 42 is configured separately from the spring support 41, and has a male screw portion 42a and an atmosphere communication path 42b. The male screw portion 42a can advance and retract to the female screw portion 22g of the cylinder head 22B. It is screwed on. The adjusting screw 42 also serves as a cap and can be rotated from the outside of the vehicle. A hexagonal head 42c for detachably attaching an adjusting tool (not shown) that can be manually operated to the outer end. Is formed. A filter 43 is attached to the atmosphere communication path 42b.

  The relief valve 50 is pressurized when the pressure of the pressurized air supplied from the pump chamber Ro to the tire air chamber Rb, that is, the air pressure (Pfr) in the air chamber Ra1, is equal to or higher than the relief set value P3 higher than the upper limit set value P2. It is for releasing air to the atmosphere, and is engaged with a valve body 51 capable of opening / closing a relief passage 31c provided in the valve body 31 at one end (movable side end). And a compression coil spring 52 that defines the movement timing of the valve body 51 (the opening timing of the relief passage 31c).

  The valve body 51 is assembled in the valve body 31 of the pressure control valve 30 so as to be movable in the cylinder axial direction, and the position of the rod portion 44 (spring support 41 of the stroke sensor S2fr is adjusted by the adjusting screw 42. Sometimes it is in contact with a rod portion that can move relatively in the cylinder axial direction with almost no resistance. The compression coil spring 52 is engaged with the above-described spring support 41 at the other end (fixed side end), and the urging force acting on the valve body 51 can be adjusted by the adjusting device 40. At the time of adjustment by the adjusting device 40, the urging force of the compression coil spring 34 acting on the valve body 31 of the pressure control valve 30 is also adjusted at the same time, and the above-described upper limit set value P2 and relief set value P3 can be adjusted simultaneously.

  In the relief valve 50, a relief passage 31 c provided in the valve body 31 of the pressure control valve 30 can be communicated with or shut off from the air chamber Ra 1 by an annular seal member 38 assembled to the valve body 31. Therefore, the valve element 31 of the pressure control valve 30 moves in the cylinder axial direction against the urging force of the compression coil springs 34 and 52, and the air chamber Ra1 and the relief passage 31c communicate with each other through the seal member 38. Only in this state, the pressure in the air chamber Ra1 is applied to the relief passage 31c so that the relief valve 50 can be operated.

  The stroke sensor S2fr detects whether the pressure control valve 30 is in a permissible state (shown state) or a prohibited state (operating state), and whether the air pump AP is in a state of generating pressurized air. In the spring support 41, a rod portion 44 that detects whether the pressurized air is not generated, detects the movement of the valve body 31 in the pressure control valve 30 through the valve body 51 in the relief valve 50, and the spring support 41. A built-in switch (not shown) that is assembled and turned on and off by the rod portion 44 is provided.

  In this stroke sensor S2fr, when the pressure control valve 30 is in an allowable state (when the air pump AP is in a state of generating pressurized air), the built-in switch is maintained in the OFF state and a Low signal is output. When the pressure control valve 30 is in a prohibited state (when the air pump AP is not generating pressurized air), the built-in switch is maintained in the ON state and a High signal is output. Signals output from the stroke sensor S2fr and the stroke sensors S2fl, S2rl, S2rr provided on the other wheels are configured to be input wirelessly to the electric control unit ECU shown in FIG.

  The pressure reducing valves VBfl, VBfr, VBrl, VBrr incorporated in each of the air pressure generating units FLA, FRA, RLA, RRA are normally closed electromagnetic on-off valves, and tire pressures of right and left wheels (for example, Pfl, Pfr or Prl). , Prr) is a pressure reducing means that discharges air from the tire air chamber on the higher tire pressure side to reduce the pressure and synchronizes the timing at which the tire pressure of the left and right wheels decreases to the lower limit set value P1, and generates air pressure. As shown in FIG. 2, the pressure reducing valve VBfr assembled to the unit FRA is assembled to the axle hub 11 and electrically connected to the electric control unit ECU as shown in FIG. .

  As shown in FIG. 4, the electric control unit ECU is electrically connected to each pressure sensor S1fl, S1fr, S1rl, S1rr and each stroke sensor S2fl, S2fr, S2rl, S2rr, and each pressure reducing valve VBfl, Each is electrically connected to VBfr, VBrl, VBrr, and includes a microcomputer.

  The microcomputer of the electric control unit ECU can repeatedly execute a program corresponding to the flowcharts of FIGS. 5 and 6 at predetermined calculation cycles (for example, 5 msec), and each pressure sensor mounted on each of the left and right front wheels FL and FR. Based on the outputs of S1fl and S1fr and the stroke sensors S2fl and S2fr, the operation of the pressure reducing valves VBfl and VBfr mounted on the left and right front wheels FL and FR can be controlled.

  Further, the microcomputer of the electric control unit ECU can repeatedly execute a program corresponding to the flowcharts of FIGS. 7 and 8 every predetermined calculation cycle (for example, 5 msec) and is mounted on the left and right rear wheels RL and RR, respectively. Based on the outputs of the pressure sensors S1rl and S1rr and the stroke sensors S2rl and S2rr, the operation of the pressure reducing valves VBrl and VBrr mounted on the left and right rear wheels RL and RR can be controlled.

  In this embodiment configured as described above, when a main switch (not shown) such as an ignition switch of the vehicle is in an ON state, the microcomputer of the electric control unit ECU is shown in the flowcharts of FIGS. The corresponding program is repeatedly executed every predetermined calculation cycle to control the operation of the pressure reducing valves VBfl and VBfr, and the program corresponding to the flowcharts of FIGS. 7 and 8 is repeatedly executed every predetermined calculation cycle. The operation of each pressure reducing valve VBrl, VBrr is controlled. When the main switch (not shown) is turned on (initial state), the pressure reducing valves VBfl, VBfr, VBrl, VBrr are closed by initialization.

(Operation when tire pressure Pfl of front left wheel is higher than tire pressure Pfr of front right wheel)
By the way, when the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR change as illustrated in FIG. 9, the microcomputer of the electric control unit ECU until the elapsed time t reaches time t2 is shown in FIGS. When the program corresponding to the flowchart of FIG. 6 is executed (for example, at time t1 in FIG. 9), steps 101, 102, 103, 104, 105, 106, 107, 111, 116, 117, and 115 are sequentially executed.

  In step 101 of FIG. 5, the microcomputer starts processing. In step 102, it is determined whether or not both of the stroke sensors S2fl and S2fr attached to the left and right front wheels FL and FR are ON. In steps 103 and 104, the left and right front wheels FL, It is determined whether or not the pressure reducing valves VBfl and VBfr attached to the FR are closed. In step 105, the time t and the tire air pressures Pfl and Pfr at that time (current time) are read and stored. In step 106, the respective pressure reduction gradients αfl and αfr of the tire air pressures Pfl and Pfr in the left and right front wheels FL and FR are respectively read. In step 107, the lower limit reaching times Tbfl and Tbfr until the tire air pressures Pfl and Pfr in the left and right front wheels FL and FR are reduced to the lower limit set value P1 are calculated and stored.

  The tire air pressure Pflo used for each calculation of the above-described pressure reduction gradient αfl and lower limit reaching time Tbfl is the tire air pressure of the left front wheel FL before the specified time Ta from the present time (for example, at t1 in FIG. 9), and the tire air pressure Pfln is a step. The tire pressure of the left front wheel FL at the present time stored in 105. Further, the tire air pressure Pfro used for the calculation of the above-described decompression gradient αfr and lower limit reaching time Tbfr is the tire air pressure of the right front wheel FR before the specified time Ta from the present time, and the tire air pressure Pfrn is the current time stored in step 105. Is the tire pressure of the right front wheel FR.

  Further, in step 111 of FIG. 6, the microcomputer compares the pressure reduction gradients αfl and αfr calculated and stored in step 106 of FIG. 5, and in the case of FIG. 9 (pressure reduction gradient of the tire air pressure Pfr in the right front wheel FR). If αfr is greater than the pressure reduction gradient αfl of the tire air pressure Pfl in the left front wheel FL), “No” is determined. Further, in step 116 of FIG. 6, the time Tcfl required for reducing the pressure reducing valve VBfl attached to the left front wheel FL from the closed front state to the lower limit value P1 is changed from the current tire pressure Pfln of the left front wheel FL to the lower limit set value P1. It is calculated and stored with reference to a map (not shown) created in advance.

  In step 117 of FIG. 6, the microcomputer determines whether or not the lower limit arrival time Tbfr calculated and stored in step 107 of FIG. 5 is smaller than the required time Tcfl calculated and stored in step 116. . Until time t2 in FIG. 9, since the lower limit arrival time Tbfr is longer (longer) than the required time Tcfl, the microcomputer makes a “No” determination at step 117 and executes the program at step 115. finish.

  Thus, when the time t2 in FIG. 9 is exceeded, the lower limit arrival time Tbfr described above becomes shorter (shorter) than the required time Tcfl, so the microcomputer determines “Yes” in step 117 and executes step 118. After that, in step 115, the execution of the program is terminated. In step 118, an open signal for maintaining the pressure reducing valve VBfl attached to the left front wheel FL from the closed state to the open state is output.

  Thereafter, when the microcomputer of the electric control unit ECU executes a program corresponding to the flowcharts of FIGS. 5 and 6, the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR are reduced to the lower limit set value P1, and the stroke is performed. Steps 101, 102, 103, and 115 are sequentially executed until the sensors S2fl and S2fr are turned from ON to OFF (see t2 to t3 in FIG. 9).

  Further, after the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR are reduced to the lower limit set value P1 and the stroke sensors S2fl, S2fr are turned from ON to OFF (the air pump AP mounted on the left and right front wheels FL, FR is added). After changing from a state in which compressed air is not generated to a state in which pressurized air is generated), the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR rise to the upper limit set value P2, and the stroke sensors S2fl, S2fr are turned on. The microcomputer sequentially executes steps 101, 102, 108, and 115 until t3 (see t3 to t5 in FIG. 9). In step 108, a closing signal (a signal for maintaining the pressure reducing valves VBfl, VBfr in a closed state) is output to the pressure reducing valves VBfl, VBfr attached to the left and right front wheels FL, FR.

  At time t4 in FIG. 9, the stroke sensor S2fl of the left front wheel FL is turned from OFF to ON, and at time t5 in FIG. 9, the stroke sensor S2fr of the right front wheel FR is turned from OFF to ON. After the elapse of time t5 in FIG. 9, when the microcomputer of the electric control unit ECU executes a program corresponding to the flowcharts in FIGS. 5 and 6, steps 101, 102, 103, 104, 105, 106, 107, 111, 116, 117, and 115 are sequentially executed.

  Therefore, in this embodiment, the tire air pressure Pfl of the left front wheel FL is decreased to the lower limit set value P1 as the tire air pressure Pfr of the right front wheel FR decreases to the lower limit set value P1 (the left and right front wheels FL, FR When the tire air pressures Pfl and Pfr of the tires are different from each other, the air is discharged from the tire air chamber on the side where the tire air pressure is higher, the pressure is reduced, and the timing at which the tire air pressures Pfl and Pfr are reduced to the lower limit set value P1 is synchronized). Is possible.

Therefore, at time t3 in FIG. 9, the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR can be simultaneously set to the lower limit set value P1, and generation of pressurized air by the air pump AP of the left front wheel FL is started. It is possible to make the timing and the generation start timing of the pressurized air by the air pump AP of the right front wheel FR the same. Further, the initial load (load at the start of driving) generated by driving the air pumps AP of the left and right front wheels FL and FR as a pump can be made the same. This eliminates the difference in rotational resistance acting on the left and right front wheels FL and FR at the start of driving of each air pump AP provided corresponding to the left and right front wheels FL and FR, and eliminates the deflection of the vehicle in the left and right direction. Is possible.

(Operation when tire pressure Pfr of right front wheel is higher than tire pressure Pfl of left front wheel)
Further, when the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR change as illustrated in FIG. 10, the microcomputer of the electric control unit ECU until the elapsed time t reaches time t2 is shown in FIGS. 6 is executed, and steps 101, 102, 103, 104, 105, 106, 107, 111, 112, 113, 115 are sequentially executed. Note that the processing in steps 101, 102, 103, 104, 105, 106, and 107 in FIG. 5 is the same as that in the above-described embodiment (the embodiment in which the tire air pressures Pfl and Pfr change as illustrated in FIG. 9). .

  In step 111 of FIG. 6, the microcomputer compares the pressure reduction gradients αfl and αfr calculated and stored in step 106 of FIG. 5. In the case of FIG. 10 (the pressure reduction gradient αfl of the tire air pressure Pfl in the left front wheel FL is If the tire pressure Pfr of the right front wheel FR is greater than the pressure reduction gradient αfr), “Yes” is determined. Further, in step 112 of FIG. 6, a time Tcfr required for reducing the pressure reducing valve VBfr attached to the right front wheel FR from the closed state to the open state from the tire pressure Pfrn of the right front wheel FR to the lower limit set value P1 at the present time It is calculated and stored with reference to a map (not shown) created in advance.

  Further, in step 113 of FIG. 6, it is determined whether or not the lower limit arrival time Tbfl calculated and stored in step 107 is smaller than the required time Tcfr calculated and stored in step 112. Until time t2 in FIG. 10, since the lower limit arrival time Tbfl is longer (longer) than the required time Tcfr, the microcomputer makes a “No” determination at step 113 and executes the program at step 115. finish.

  Thus, when the time t2 in FIG. 10 is exceeded, the lower limit arrival time Tbfl described above becomes shorter (shorter) than the required time Tcfr, so the microcomputer determines “Yes” in step 113 and executes step 114. After that, in step 115, the execution of the program is terminated. In step 114, an open signal for maintaining the pressure reducing valve VBfr attached to the right front wheel FR from the closed state to the open state is output.

  Thereafter, when the microcomputer of the electric control unit ECU executes a program corresponding to the flowcharts of FIGS. 5 and 6, the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR are reduced to the lower limit set value P1, and the stroke is performed. Steps 101, 102, 103, 104, and 115 are sequentially executed until the sensors S2fl and S2fr are turned from ON to OFF (see t2 to t3 in FIG. 10).

  Further, after the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR are reduced to the lower limit set value P1 and the stroke sensors S2fl, S2fr are turned from ON to OFF (the air pump AP mounted on the left and right front wheels FL, FR is added). After changing from a state in which compressed air is not generated to a state in which pressurized air is generated), the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR rise to the upper limit set value P2, and the stroke sensors S2fl, S2fr are turned on. The microcomputer sequentially executes steps 101, 102, 108, and 115 until t3 (see t3 to t5 in FIG. 10). In step 108, a closing signal (a signal for maintaining the pressure reducing valves VBfl, VBfr in a closed state) is output to the pressure reducing valves VBfl, VBfr attached to the left and right front wheels FL, FR.

  At time t4 in FIG. 10, the stroke sensor S2fr for the right front wheel FR is turned on from OFF, and at time t5 in FIG. 10, the stroke sensor S2fl for the left front wheel FL is turned on from OFF. Further, after the time t5 in FIG. 10 has elapsed, when the microcomputer of the electric control unit ECU executes the program corresponding to the flowcharts in FIGS. 5 and 6, steps 101, 102, 103, 104, 105, 106, 107, 111, 112, 113, 115 are sequentially executed.

  Therefore, in this embodiment, the tire air pressure Pfr of the right front wheel FR is decreased to the lower limit set value P1 as the tire air pressure Pfl of the left front wheel FL decreases to the lower limit set value P1 (the left and right front wheels FL, FR When the tire air pressures Pfl and Pfr of the tires are different from each other, the air is discharged from the tire air chamber on the side where the tire air pressure is higher, the pressure is reduced, and the timing at which the tire air pressures Pfl and Pfr are reduced to the lower limit set value P1 is synchronized) Is possible.

For this reason, at time t3 in FIG. 10, the tire air pressures Pfl, Pfr of the left and right front wheels FL, FR can be simultaneously set to the lower limit set value P1, and generation of pressurized air by the air pump AP of the left front wheel FL is started. It is possible to make the timing and the generation start timing of the pressurized air by the air pump AP of the right front wheel FR the same. Further, the initial load (load at the start of driving) generated by driving the air pumps AP of the left and right front wheels FL and FR as a pump can be made the same. This eliminates the difference in rotational resistance acting on the left and right front wheels FL and FR at the start of driving of each air pump AP provided corresponding to the left and right front wheels FL and FR, and eliminates the deflection of the vehicle in the left and right direction. Is possible.

(Operation when tire pressure Prl of left rear wheel is higher than tire pressure Prr of right rear wheel)
Further, when the tire air pressures Prl, Prr of the left and right rear wheels RL, RR change as illustrated in FIG. 11, the microcomputer of the electric control unit ECU changes the time shown in FIG. 7 until the elapsed time t reaches the time t2. When the program corresponding to the flowchart of FIG. 8 is executed (for example, at the time t1 of FIG. 11), steps 201, 202, 203, 204, 205, 206, 207, 211, 216, 217, and 215 are executed sequentially.

  In step 201 of FIG. 7, the microcomputer starts processing, and in step 202, it is determined whether or not both the stroke sensors S2rl and S2rr attached to the left and right rear wheels RL and RR are ON. In steps 203 and 204, the left and right rear wheels are determined. It is determined whether or not the pressure reducing valves VBrl and VBrr attached to RL and RR are closed. In step 205, the time t and the tire air pressures Prl and Prr at that time (current time) are read and stored. In step 206, the pressure reduction gradients αrl and αrr of the tire air pressures Prl and Prr at the left and right rear wheels RL and RR are determined. In step 207, the lower limit reaching times Tbrl and Tbrr until the tire air pressures Prl and Prr at the left and right rear wheels RL and RR decrease to the lower limit set value P1 are calculated and stored.

  The tire air pressure Prlo used for each calculation of the above-described decompression gradient αrl and lower limit reaching time Tbrl is the tire air pressure of the left rear wheel RL before the specified time Ta from the present time (for example, at t1 in FIG. 11), and the tire air pressure Prln is The tire air pressure of the left rear wheel RL stored at step 205 at the present time. Further, the tire air pressure Proro used in each calculation of the above-described pressure reduction gradient αrr and the lower limit reaching time Tbrr is the tire air pressure of the right rear wheel RR before the specified time Ta from the present time, and the tire air pressure Prrn is stored in step 205. This is the tire pressure of the right rear wheel RR at the present time.

  Further, in step 211 of FIG. 8, the microcomputer compares the pressure reduction gradients αrl and αrr calculated and stored in step 206 of FIG. 7, and in the case of FIG. 11 (the pressure reduction of the tire air pressure Prr at the right rear wheel RR). If the gradient αrr is greater than the pressure-reducing gradient αrl of the tire air pressure Prl at the left rear wheel RL), “No” is determined. Further, in step 216 of FIG. 8, the time required for the pressure reducing valve VBrl attached to the left rear wheel RL from the current tire air pressure Prln of the left rear wheel RL to be lowered from the closed state to the lower limit set value P1. Tcrl is calculated and stored with reference to a previously created map (not shown).

  In step 217 of FIG. 8, the microcomputer determines whether the lower limit reaching time Tbrr calculated and stored in step 207 of FIG. 7 is smaller than the required time Tcrl calculated and stored in step 216. . Since the lower limit arrival time Tbrr is longer (longer) than the required time Tcrl until time t2 in FIG. 11, the microcomputer determines “No” in step 217 and executes the program in step 215. finish.

  Thus, if the time t2 in FIG. 11 is exceeded, the lower limit arrival time Tbrr described above becomes shorter (shorter) than the required time Tcrl, so the microcomputer determines “Yes” in step 217 and executes step 218. After that, in step 215, the execution of the program is terminated. In step 218, an open signal is output to maintain the pressure reducing valve VBrl attached to the left rear wheel RL from the closed state to the open state.

  Thereafter, when the microcomputer of the electric control unit ECU executes a program corresponding to the flowcharts of FIGS. 7 and 8, the tire air pressures Prl and Prr of the left and right rear wheels RL and RR are reduced to the lower limit set value P1. Steps 201, 202, 203, and 215 are sequentially executed until the stroke sensors S2rl and S2rr are turned from ON to OFF (see t2 to t3 in FIG. 11).

  Further, after the tire air pressures Prl and Prr of the left and right rear wheels RL and RR are reduced to the lower limit set value P1 and the stroke sensors S2rl and S2rr are turned from ON to OFF (the air pump AP mounted on the left and right rear wheels RL and RR). After changing from a state in which no pressurized air is generated to a state in which pressurized air is generated), the tire air pressures Prl, Prr of the left and right rear wheels RL, RR rise to the upper limit set value P2, and the stroke sensors S2rl, The microcomputer sequentially executes steps 201, 202, 208, and 215 until S2rr is turned on (see t3 to t5 in FIG. 11). In step 208, a close signal (a signal for maintaining the pressure reducing valves VBrl, VBrr in a closed state) is output to the pressure reducing valves VBrl, VBrr attached to the left and right rear wheels RL, RR.

  At time t4 in FIG. 11, the stroke sensor S2rl of the left rear wheel RL is turned from OFF to ON, and at time t5 in FIG. 11, the stroke sensor S2rr of the right rear wheel RR is turned from OFF to ON. After the elapse of time t5 in FIG. 11, when the microcomputer of the electric control unit ECU executes the program corresponding to the flowcharts in FIGS. 7 and 8, steps 201, 202, 203, 204, 205, 206, 207, 211, 216, 217, and 215 are sequentially executed.

  Therefore, in this embodiment, the tire air pressure Prl of the left rear wheel RL is decreased to the lower limit set value P1 as the tire air pressure Prr of the right rear wheel RR decreases to the lower limit set value P1 (the left and right rear wheels). When tire pressures Prl and Prr of RL and RR are different, air is discharged from the tire air chamber on the higher tire pressure side to reduce the pressure, and the timing at which the tire pressures Prl and Prr are reduced to the lower limit set value P1 is synchronized. Is possible.

For this reason, at time t3 in FIG. 11, the tire air pressures Prl, Prr of the left and right rear wheels RL, RR can be simultaneously set to the lower limit set value P1, and the pressurized air by the air pump AP of the left rear wheel RL can be reduced. The generation start timing and the generation start timing of the pressurized air by the air pump AP of the right rear wheel RR can be the same. Further, the initial load (load at the start of driving) generated by driving the air pumps AP of the left and right rear wheels RL and RR as a pump can be made the same. This eliminates the difference in rotational resistance acting on the left and right rear wheels RL and RR at the start of driving of the air pumps AP provided corresponding to the left and right rear wheels RL and RR, thereby eliminating the deflection of the vehicle in the left and right direction. It is possible.

(Operation when tire pressure Prr of right rear wheel is higher than tire pressure Prl of left rear wheel)
Further, when the tire air pressures Prl, Prr of the left and right rear wheels RL, RR change as illustrated in FIG. 12, the microcomputer of the electric control unit ECU changes the time shown in FIG. 7 until the elapsed time t reaches the time t2. The program corresponding to the flowchart of FIG. 8 is executed, and steps 201, 202, 203, 204, 205, 206, 207, 211, 212, 213, and 215 are executed sequentially. Note that the processing in steps 201, 202, 203, 204, 205, 206, and 207 in FIG. 7 is the same as that in the above-described embodiment (the embodiment in which the tire air pressures Pfl and Pfr change as illustrated in FIG. 11). .

  In step 211 of FIG. 8, the microcomputer compares the decompression gradients αrl and αrr calculated and stored in step 206 of FIG. 7, and in the case of FIG. 12 (the decompression gradient αrl of the tire air pressure Prl at the left rear wheel RL). Is greater than the pressure-reducing gradient αrr of the tire air pressure Prr at the right rear wheel RR). Further, in step 212 of FIG. 8, the time required for the pressure reducing valve VBrr mounted on the right rear wheel RR from the current tire pressure Prrn of the right rear wheel RR to be lowered from the closed state to the lower limit set value P1. Tcrr is calculated and stored with reference to a previously created map (not shown).

  Further, in step 213 in FIG. 8, it is determined whether or not the lower limit arrival time Tbrl calculated and stored in step 207 is smaller than the required time Tcrr calculated and stored in step 212. Until time t2 in FIG. 12, since the lower limit arrival time Tbrl is longer (longer) than the required time Tcrr, the microcomputer determines “No” in step 213 and executes the program in step 215. finish.

  Thus, when the time t2 in FIG. 12 is exceeded, the above-described lower limit arrival time Tbrl becomes shorter (shorter) than the required time Tcrr, so the microcomputer determines “Yes” in step 213 and executes step 214. After that, in step 215, the execution of the program is terminated. In step 214, an open signal for maintaining the pressure reducing valve VBrr attached to the right rear wheel RR from the closed state to the open state is output.

  Thereafter, when the microcomputer of the electric control unit ECU executes a program corresponding to the flowcharts of FIGS. 7 and 8, the tire air pressures Prl and Prr of the left and right rear wheels RL and RR are reduced to the lower limit set value P1. Steps 201, 202, 203, 204, and 215 are sequentially executed until the stroke sensors S2rl and S2rr are turned from ON to OFF (see t2 to t3 in FIG. 12).

  Further, after the tire air pressures Prl and Prr of the left and right rear wheels RL and RR are reduced to the lower limit set value P1 and the stroke sensors S2rl and S2rr are turned from ON to OFF (the air pump AP mounted on the left and right rear wheels RL and RR). After changing from a state in which no pressurized air is generated to a state in which pressurized air is generated), the tire air pressures Prl, Prr of the left and right rear wheels RL, RR rise to the upper limit set value P2, and the stroke sensors S2rl, The microcomputer sequentially executes steps 201, 202, 208, and 215 until S2rr is turned on (see t3 to t5 in FIG. 12). In step 208, a close signal (a signal for maintaining the pressure reducing valves VBrl, VBrr in a closed state) is output to the pressure reducing valves VBrl, VBrr attached to the left and right front wheels FL, FR.

  At time t4 in FIG. 12, the stroke sensor S2rr for the right rear wheel RR is turned from OFF to ON, and at time t5 in FIG. 12, the stroke sensor S2rl for the left rear wheel FL is turned from OFF to ON. Further, after the time t5 of FIG. 12 has elapsed, when the microcomputer of the electric control unit ECU executes a program corresponding to the flowcharts of FIGS. 7 and 8, steps 201, 202, 203, 204, 205, 206, 207, 211, 212, 213, and 215 are sequentially executed.

  Therefore, in this embodiment, the tire air pressure Prr of the right rear wheel RR is decreased to the lower limit set value P1 as the tire air pressure Prl of the left rear wheel RL decreases to the lower limit set value P1 (the left and right rear wheels). When tire pressures Prl and Prr of RL and RR are different, air is discharged from the tire air chamber on the higher tire pressure side to reduce the pressure, and the timing at which the tire pressures Prl and Prr are reduced to the lower limit set value P1 is synchronized. Is possible.

Therefore, at time t3 in FIG. 12, the tire air pressures Prl, Prr of the left and right rear wheels RL, RR can be simultaneously set to the lower limit set value P1, and the pressure of the pressurized air by the air pump AP of the left rear wheel RL can be reduced. The generation start timing and the generation start timing of the pressurized air by the air pump AP of the right rear wheel RR can be the same. Further, the initial load (load at the start of driving) generated by driving the air pumps AP of the left and right rear wheels RL and RR as a pump can be made the same. This eliminates the difference in rotational resistance acting on the left and right rear wheels RL and RR at the start of driving of the air pumps AP provided corresponding to the left and right rear wheels RL and RR, thereby eliminating the deflection of the vehicle in the left and right direction. It is possible.

1 is an overall configuration diagram schematically illustrating an embodiment of a four-wheeled vehicle including a tire pressure control device according to the present invention. It is the principal part longitudinal cross-sectional front view which showed a part of air pressure production | generation unit provided in the right front wheel shown in FIG. 1 in detail. It is sectional drawing of the whole air pressure production | generation unit shown in FIG. It is a block diagram which shows the electric control circuit for controlling the action | operation of each pressure reducing valve shown in FIG. 6 is a flowchart showing a part of a program (front wheel program) executed by a microcomputer of the electric control device shown in FIG. FIG. 5 is a flowchart showing a remaining part of a program (front wheel program) executed by the microcomputer of the electric control device shown in FIG. 4. FIG. 5 is a flowchart showing a part of a program (rear wheel program) executed by the microcomputer of the electric control device shown in FIG. 4. FIG. 5 is a flowchart showing a remaining part of a program (rear wheel program) executed by the microcomputer of the electric control device shown in FIG. 4. FIG. It is an operation explanatory view in case the tire pressure of the left front wheel is higher than the tire pressure of the right front wheel. It is an operation explanatory view in case the tire pressure of the right front wheel is higher than the tire pressure of the left front wheel. It is an operation explanatory view in case the tire pressure of the left rear wheel is higher than the tire pressure of the right rear wheel. It is an operation explanatory view in case the tire pressure of the right rear wheel is higher than the tire pressure of the left rear wheel.

Explanation of symbols

FL, FR: front left and right wheels, RL, RR ... rear left and right wheels, FLA, FRA, RLA, RRA ... air pressure generating unit, AP ... air pump, VA ... control valve device, VBfl, VBfr, VBrl, VBrr ... pressure reducing valve, Rb Tire air chamber, S1fl, S1fr, S1rl, S1rr ... Pressure sensor, S2fl, S2fr, S2rl, S2rr ... Stroke sensor, ECU ... Electric control device

Claims (1)

It is provided corresponding to the left and right wheels of the vehicle, and is driven as a pump by the rotation of each wheel until the tire air pressure of each wheel in the left and right wheels decreases to the lower limit set value and increases to the upper limit set value. Generates pressurized air to be supplied to the tire air chamber of the wheel, and as a pump by rotation of each wheel until the tire air pressure of each wheel rises to the upper limit set value and decreases to the lower limit set value A pair of left and right air pump devices that stop driving and stop generating pressurized air;
When the tire pressures on the left and right wheels are different, the air pumps discharge the air from the tire air chamber on the higher tire pressure side to reduce the pressure, and synchronize the timing at which the tire pressures on the left and right wheels decrease to the lower limit set value. A tire pressure control device comprising pressure reducing means as synchronizing means for synchronizing the generation start timing of pressurized air by the device.

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