JP5105995B2 - Air circuit - Google Patents

Description

  The present invention relates to an air circuit of an air suspension device that adjusts the vehicle height by supplying and discharging compressed air to and from an air spring interposed between a vehicle body and an axle.

  Conventionally, as an air circuit that supplies and discharges compressed air to and from an air spring interposed between a vehicle body and an axle, for example, a compressor, a high-pressure tank that accumulates pressure by the compressor, and a low-pressure tank that accumulates pressure by exhaust from the air spring A supply line for connecting the compressor and the high pressure tank to the air spring, an electromagnetic on-off valve for supplying compressed air provided in the middle of the supply line, and a 3-port 2 for selectively communicating the air spring with the supply line and the discharge line The electromagnetic directional control valve at the position, the electromagnetic on-off valve for exhaust provided in the middle of the discharge line, and the exhaust pressure from the air spring driven by the pressure upstream and downstream of the orifice provided in the middle of the exhaust line as pilot pressure And a three-port two-position directional switching valve that determines whether to supply to the low-pressure tank or open to the atmosphere (for example, See Patent Document 1). In addition, the above-mentioned electromagnetic direction switching valve is provided in four corresponding to the air springs interposed at four locations between the vehicle body and the axle of the automobile.

  In this conventional air circuit, when the vehicle height is raised, compressed air is sent from the high pressure tank only or from the high pressure tank and the compressor to the air spring, and conversely, when the vehicle height is lowered, the pressure in the low pressure tank is less than the predetermined pressure. If so, the air discharged from the air spring is preferentially sent to the low-pressure tank, and the low-pressure tank is accumulated.

  And, the compressor basically sucks from the low-pressure tank and sends the compressed air to the high-pressure tank or the air spring. By adopting such a configuration, the compression ratio of air by the compressor is reduced, Energy consumption in the compressor is reduced.

  In addition, when the pressure in the low-pressure tank is lower than the atmospheric pressure, it is more efficient for the compressor to suck in the air than in the low-pressure tank. Therefore, in this air circuit, the low-pressure tank that is the suction destination of the compressor In order to make it possible to select an advantageous one of the atmosphere, a 3-port 2-position directional switching valve driven by using the pressure in the low-pressure tank as a pilot pressure is provided.

Therefore, in this conventional air circuit, compressed air can be supplied to the air spring even if the compressor is not always driven with a high-pressure tank, the compression ratio of the air by the compressor is reduced by providing a low-pressure tank, and the suction of the compressor Since it is possible to select the more advantageous one, the energy consumption of the compressor can be reduced.
Japanese Patent Application Laid-Open No. 10-119531 (Embodiment of the Invention, FIG. 1)

  As described above, the conventional air circuit is useful in that the energy consumption of the compressor can be reduced, but there are problems in the following points.

  That is, in the above-mentioned air circuit, there are two on-off valves in the circuit, six directional switching valves including electromagnetic and non-electromagnetic types, and a total of eight valve elements are installed. In the three-port two-position directional switching valve, a sliding spool or a rotary spool is generally used as a valve body. For example, a valve using a spool can completely block the passage. Therefore, the entire circuit cannot be sealed because of leakage, and air leaks to the atmosphere due to leakage by the direction switching valve, resulting in energy loss.

  Further, in order to configure the direction switching valve at the 3 port 2 position as a poppet type, not only the structure is complicated, but also the valve itself becomes large, which increases the cost of the air circuit and increases the size to the vehicle. This is also disadvantageous in terms of mountability.

In order to achieve the above object, the means of the present invention is to connect a compressor and a discharge side and a suction side of the compressor in an air circuit that supplies and discharges compressed air to and from an air spring interposed between a vehicle body and an axle. A loop line, a poppet type electromagnetic switching valve provided in the middle of the loop line for opening and closing the loop line, and a supply line for connecting the discharge side of the compressor and the air spring in the middle of the loop line. A high-pressure tank that is connected in the middle of the loop line to the discharge side of the compressor from the switching valve via a charge line, and a poppet electromagnetic switching charge valve that is provided in the middle of the charge line to open and close the charge line , a low pressure tank is connected to the suction side of the compressor from the switching valve in the middle of the loop line, switching to a middle of the loop line A recycle line that connects the compressor suction side to the high pressure tank side from the charge valve and the high pressure tank side from the charge valve, and reverse that is provided in the middle of the recycle line and allows only the flow from the loop line side to the charge line side And a stop valve .

  An object of the present invention is to provide a compressor, a loop line connecting a discharge side and a suction side of the compressor, and a loop line in an air circuit for supplying and discharging compressed air to an air spring interposed between a vehicle body and an axle. A poppet type electromagnetic switching type switching valve provided in the middle of the loop, a supply line connecting the compressor discharge side and the air spring from the switching valve in the middle of the loop line, and in the middle of the loop line A high-pressure tank connected to the discharge side of the compressor from the switching valve via a charge line, a poppet electromagnetic switching charge valve provided in the middle of the charge line to open and close the charge line, and in the middle of the loop line And a low-pressure tank connected to the suction side of the compressor from the switching valve.

  According to the air circuit of the present invention, since the charge valve and the switching valve in the air circuit are a two-port two-position poppet-type on-off valve with high hermeticity, there is no fear of air leakage, and Since no air leakage occurs, no energy loss occurs.

  In addition to not causing energy loss due to air leakage, it is possible to reduce the compression ratio of the air by the compressor by accumulating the low-pressure tank and to avoid the constant drive of the compressor by providing the high-pressure tank. Energy consumption is further reduced compared to the conventional air circuit.

  In addition, the charge valve and switching valve in the air circuit are highly poppet-type on-off valves, so the valve structure is simple and high accuracy like a directional switching valve that must use a spool valve. Therefore, the manufacturing cost of the air circuit can be reduced and the entire air circuit can be saved in the vehicle space. Mountability can also be improved.

  FIG. 1 is a view showing an air circuit according to an embodiment of the present invention. FIG. 2 is a list showing the operation modes of the air circuit according to the embodiment of the present invention.

  The air circuit 1 of the present invention will be described below based on the embodiment shown in the drawings. As shown in FIG. 1, the air circuit 1 according to one embodiment supplies and discharges compressed air to and from four air springs A interposed between four wheels and a vehicle body of the vehicle. Similarly, the air spring A is integrated with the outer periphery of a damper D interposed between each of the four wheels of the vehicle and the vehicle body, and forms an air suspension in cooperation with the damper D.

  In the air suspension shown in FIG. 1, the air spring A and the damper D are integrated, but the air spring A and the damper D may be installed independently.

  The damper D is well known and will not be described in detail. The damper D includes a cylinder S and a rod R inserted through the cylinder S, and exhibits a predetermined damping force when the rod R enters and exits the cylinder S. It is like that.

  The air spring A includes a bottomed cylindrical chamber C connected to the rod R, and a cylindrical diaphragm E connected to the opening of the chamber C and the side of the cylinder S of the damper D. An air chamber G is formed around the outer periphery and functions as a suspension spring that supports the weight of the vehicle body. Therefore, when the pressure in the air chamber G in the air spring A is increased by expanding the volume of the air chamber G by supplying compressed air from the air circuit 1, the vehicle body can be raised, and conversely, the air circuit 1 to exhaust the air in the air chamber G and reduce the volume of the air chamber G, the vehicle body can be lowered, that is, the volume of the air chamber A in the air spring A is controlled by the air circuit 1 to High adjustment is possible.

  Further, when the vehicle height changes due to passengers or cargo, the vehicle height can be kept constant by controlling the pressure in the air chamber G with respect to the weight change.

  As shown in FIG. 1, the air circuit 1 basically includes a compressor 2, a loop line 3 connecting a discharge side discharge port 2 a and a suction side suction port 2 b of the compressor 2, and a loop line 3. 2 port 2 position poppet type electromagnetic switching type switching valve 4 that opens and closes the loop line 3, and the middle of the loop line 3 from the switching valve 4 to the outlet 2 a side of the compressor 2 and the air spring A Are provided in the middle of the charge line 6, the high-pressure tank 7 connected to the discharge port 2 a side of the compressor 2 from the switching valve 4 through the charge line 6. 2 port 2 position poppet type electromagnetic switching type charge valve 8 that opens and closes the charge line 6, and a suction port 2 of the compressor 2 from the switching valve 4 in the middle of the loop line 3. It is constituted by a low-pressure tank 9 connected to the side.

  Thus, in the air circuit 1, the discharge port 2 a of the compressor 2 is connected to the high-pressure tank 7 via the loop line 3 and the charge line 6, and the high-pressure tank 7 is accumulated by the compressor 2, Basically, by supplying compressed air from the high pressure tank 7 to the air chamber G of the air spring A, the vehicle height can be adjusted without always driving the compressor 2, and the loop The suction port 2b of the compressor 2 is connected to the low-pressure tank 9 that accumulates the pressure higher than the atmospheric pressure via the line 3, and the suction pressure of the compressor 2 is increased to the atmospheric pressure by suctioning the compressor 2 from the low-pressure tank 9. The compression ratio can be reduced, and the energy consumption of the compressor 2 can be reduced.

  Hereinafter, the air circuit 1 will be described in detail. When the compressor 2 is driven by the motor M, the compressor 2 sucks air from the suction port 2b and sends compressed air from the discharge port 2a to the loop line 3. In addition to driving by the motor M, the compressor 2 can be driven by taking out power from an engine mounted on the vehicle. Further, when the vehicle is provided with a hydraulic pump, the motor M can be driven. A hydraulic motor may be used instead of an electric motor.

  On the loop line 3, a check valve 10 that allows only the flow from the upstream side to the downstream side in order from the upstream side that is the discharge side in the compressor 2, the dryer 11 that dries the air sent from the compressor 2, the air A throttle 12 that provides resistance to the flow of the gas, a check valve 13 that is arranged in parallel with the throttle 12 and allows only a flow from the upstream side to the downstream side, the connection X of the supply line 5 and the charge line 6, the switching valve 4 and Low-pressure tanks 9 are arranged and provided.

  In this case, the dryer 11 employs an adsorption type, and contains therein a desiccant that adsorbs moisture such as silica gel and activated alumina, and adsorbs moisture of compressed air passing through the interior with the desiccant. Thus, the compressed air can be dried. In addition, when a desiccant adsorb | sucks until a water | moisture content is saturated, dry air is passed and it is made to dry. In addition, you may make it heat a desiccant with the passage of the dry air for drying of the said desiccant.

  The check valve 10 is provided to prevent air from being led to the discharge port 2a of the compressor 2 when the air is released from the air chamber G of the air spring A described later to release the air to the atmosphere. When the compressor 2 supplies compressed air, the passage of air is allowed without resistance.

  Further, as will be described in detail later, in the case of this embodiment, when the air is discharged from the air chamber G of the air spring A and the air is released to the atmosphere, the upstream side of the connection portion X of the supply line 5 of the loop line 3 The above-described throttle 12 employs a structure that exhausts the air, and provides a resistance to the air flow to limit the exhaust speed from the air chamber G. Since air is allowed to pass slowly, the dryer 11 can be sufficiently dried.

  Further, the check valve 13 arranged downstream of the dryer 11 and in parallel with the throttle 12 positively allows the passage of air in preference to the throttle 12 when the compressor 2 supplies compressed air. It is provided so as not to cause energy loss due to the throttle 12 when compressed air is supplied. When the air is released from the air chamber G for the purpose of drying the dryer 11, only the throttle 12 is allowed to pass through the air. It is functioning.

  Subsequently, a high pressure tank 7 is connected to the connection portion X of the loop line 3 via a charge line 6, and a charge valve 8 is provided in the middle of the charge line 6. The charge valve 8 has a communication position 8a that opens the charge line 6 to allow the loop line 3 and the high-pressure tank 7 to communicate with each other, and a blocking position 8b that blocks the charge line 6. The charge valve 8 is provided at one end and has a blocking position 8b. And a solenoid 8d provided at the other end and opposed to the spring 8c. When the solenoid 8d is excited, the two-port is switched from the shut-off position 8c to the communication position 8a. It is configured as a two-position poppet electromagnetic switching on-off valve.

  Although not shown in the figure, the 2-port 2-position poppet on-off valve can seal the annular valve seat, the conical surface that separates and closes the valve seat, and the axial end of the valve seat. It is composed of a valve body with a flexible elastic body, etc., and has an extremely high sealing performance compared to a spool valve, so there is no fear of air leakage, it is also resistant to contamination, and has an advantage of excellent response speed. is doing.

  When the charge valve 8 is in the communication position 8a, the high-pressure tank 7 is in communication with the loop line 3. When the compressor 2 is driven, compressed air is supplied to the high-pressure tank 7 to store the high-pressure tank 7. Conversely, when the compressed air is discharged from the high-pressure tank 7, the compressed air can be supplied to the air chamber G of the air spring A via the supply line 5.

  On the other hand, when the charge valve 8 is set to the shut-off position 8b, the high-pressure tank 7 is shut off from the loop line 3, and the high-pressure tank 7 is maintained in the accumulated state.

  A pressure sensor 30 is installed on the charge line 6 on the high pressure tank 7 side from the charge valve 8. An unillustrated ECU that controls the air circuit 1 monitors the pressure in the high-pressure tank 7 with the pressure sensor 30 and drives the compressor 2 when the pressure in the high-pressure tank 7 falls below a predetermined high-pressure tank lower limit value. The charge valve 8 is switched to the communication position 8a to accumulate the high-pressure tank 7 up to a predetermined high-pressure tank upper limit value. When the pressure in the high-pressure tank 7 reaches the predetermined high-pressure tank upper limit value, the charge valve 8 is switched to the cutoff position 8b. The drive of the compressor 2 is stopped. Note that the switching valve 4 provided on the downstream side of the charge line 6 and the supply line 5 on the loop line 3 is kept closed when the high-pressure tank 7 accumulates pressure.

  Furthermore, the supply line 5 connected to the connecting portion X on the discharge port 2a side of the compressor 2 from the switching valve 4 along with the charge line 6 in the middle of the loop line 3 is branched into four on the way, The four air springs A are respectively connected to the air chambers G of the four air springs A interposed between the four wheels and the vehicle body.

  In order to control the supply / discharge of compressed air to / from each air spring A, a poppet electromagnetic switching control valve 14 for opening and closing the supply line 5 is provided in the middle of the supply line 5 and immediately before each air spring A. It has been. That is, four control valves 14 are provided corresponding to each air spring A, and supply of compressed air to the air chamber G of the corresponding air spring A and exhaust from the air chamber G, respectively. ing.

  Each of the control valves 14 has a communication position 14a that opens the supply line 5 to allow the loop line 3 and the air spring A to communicate with each other, and a blocking position 14b that blocks the supply line 5, and is provided at one end. There is provided a spring 14c for energizing to take the blocking position 14b and a solenoid 14d provided at the other end and facing the spring 14c. When the solenoid 14d is excited, the switching position 14c is switched to the communication position 14a. It is configured as a two-port, two-position poppet-type electromagnetic switching on-off valve.

  The control valve 14 is controlled to be switched by the ECU (not shown). During a failure, the supply line 5 is shut off to lock the air chamber G of each air spring A so that the vehicle height does not change. , To ensure that failsafe can be performed.

  Further, the switching valve 4 is installed in the middle of the loop line 3 and between the supply line 5 and the charge line 6 and the low-pressure tank 9, and basically, when the vehicle height is lowered, the loop line 4 3 is released.

  More specifically, the switching valve 4 has a communication position 4a for opening the loop line 3 and a blocking position 4b for blocking the loop line 3, and is provided at one end and urged to take the blocking position 4b. 4c and a solenoid 4d provided at the other end and opposed to the spring 4c. When this solenoid 4d is excited, it switches from the shut-off position 4c to the communication position 4a. It is configured as an on-off valve.

  Therefore, if the switching valve 4 is maintained at the communication position 4a and each control valve 14 is opened, the compressed air exhausted from the air chamber G can be guided to the low-pressure tank 9, and the air chamber G The low pressure tank 9 can be accumulated with compressed air exhausted from the tank.

  A pressure sensor 31 that detects the pressure in the low-pressure tank 9 is installed in the middle of the loop line 3, and an unillustrated ECU that controls the air circuit 1 monitors the pressure in the low-pressure tank 9 with the pressure sensor 31. If the pressure in the low pressure tank 9 becomes higher than the predetermined upper limit value of the low pressure tank, the compressor 2 is driven to expedite exhaust from the air chamber G to prevent the lowering speed of the vehicle height from decreasing. The air discharged from the compressor 2 is released to the atmosphere via an exhaust valve 21 described later.

  Further, in the middle of the loop line 3, the recycle line 15 connects between the switching valve 4 and the suction port 2 b of the compressor 2 and in the middle of the charge line 6 to the high-pressure tank 7 side from the charge valve 8. In the middle of the recycle line 15, a check valve 16 that allows only the flow from the loop line 3 side to the charge line 6 side is provided.

  When the compressed air is exhausted from the air chamber G of the air spring A, when the pressure in the low pressure tank 9 rises and exceeds the pressure in the high pressure tank 9 due to accumulated pressure in the low pressure tank 9, The check valve 16 opens the recycle line 15 so that the high-pressure tank 7 can be accumulated through the recycle line 15. Accordingly, the compressed air exhausted from the air chamber G can be used not only for accumulating the low-pressure tank 9 but also for accumulating the high-pressure tank 7, thereby reducing the drive opportunity of the compressor 2 and further reducing energy consumption. be able to.

  Next, a suction line 17 that allows the compressor 2 to suck in the atmosphere is connected between the low-pressure tank 9 of the loop line 3 and the suction port 2 b of the compressor 2. In the middle of the suction line 17, there are provided a filter 18 and a check valve 19 that allows only a flow from the atmosphere side to the loop line 3 side on the loop line 3 side from the filter 18.

  Therefore, in addition to the suction from the low-pressure tank 9, the compressor 2 sucks the air through the suction line 17 and sends the compressed air to the loop line 3, and compresses it into the air chamber G of the air spring A through the supply line 5. Air can be supplied.

  Then, the atmosphere sucked into the compressor 2 through the suction line 17 passes through the filter 18 to be cleaned by removing dust and dirt contained in the atmosphere.

  The check valve 19 opens the suction line 17 when the pressure in the low-pressure tank 9 is equal to or lower than the atmospheric pressure. The presence of the check valve 19 causes the pressure in the low-pressure tank 9 to be opened. Is higher than the atmospheric pressure, the compressor 2 can preferentially receive the supply of air from the low-pressure tank 9, and the compressor 2 does not enter the suction line 17 until the pressure in the low-pressure tank 9 becomes lower than the atmospheric pressure. Air will be sucked in through. Therefore, there is no need to install a directional switching valve that complicates the configuration for selecting whether the compressor 2 sucks air from the low-pressure tank 9 or sucks the atmosphere, and there is no fear of air leakage from the air circuit 1. .

  Further, in the middle of the loop line 3, between the check valve 10 and the dryer 11, and between the filter 18 and the check valve 19 of the suction line 17 are connected by an exhaust line 20, In the middle of the exhaust line 20, a 2-port 2-position poppet electromagnetic switching exhaust valve 21 for opening and closing the exhaust line 20 is provided.

  More specifically, the exhaust valve 21 has a communication position 21a for opening the exhaust line 20 and a shut-off position 20b for shutting off the exhaust line 20, and is provided at one end to be urged to take the shut-off position 21b. 21c and a solenoid 21d provided at the other end and opposed to the spring 20c. When this solenoid 21d is excited, the two-port two-position poppet type electromagnetic switching type is switched from the cutoff position 21c to the communication position 21a. It is configured as an on-off valve.

  The driving of the compressor 2, the switching valve 4, the charge valve 8, the control valve 14, and the exhaust valve 21 are each controlled by an ECU (not shown).

  Next, the operation of the air circuit 1 configured as described above will be described. First, as shown in FIG. 2, when accumulating the high-pressure tank 7, the ECU drives the compressor 2 and applies the solenoid 8d to switch the charge valve 8 to the communication position 8a. The valve 14 and the exhaust valve 21 are not energized, and control is performed so that each of the shutoff positions 4b, 14b, and 21b is taken, and the high pressure tank pressure accumulation mode is entered.

  Then, compressed air is supplied to the high-pressure tank 7 by driving the compressor 2, the high-pressure tank 7 is accumulated until the pressure in the high-pressure tank 7 reaches the upper limit of the high-pressure tank, and when the accumulation is completed, the compressor 2 is stopped, The application to the solenoid 8d is also stopped and switched to the cutoff position 8b of the charge valve 8, and the switching valve 4, the control valve 14 and the exhaust valve 21 are maintained at the cutoff positions 4b, 14b and 21b as they are.

  When accumulating the pressure in the high-pressure tank 7, the compressor 2 sucks in air compressed from the accumulated low-pressure tank 9 to atmospheric pressure or higher, compresses the air, and discharges it to the loop line 3. Therefore, the compression ratio in the compressor 2 is atmospheric. Therefore, the pressure in the high-pressure tank 7 can be stored with less energy consumption. Further, when the pressure in the low pressure tank 9 becomes atmospheric pressure or less, the check valve 19 automatically opens and sucks air from the suction line 17, so that suction from the low pressure tank 9 and suction from the atmosphere are performed. There is no need to switch by control, and energy consumption in the air circuit 1 can also be suppressed in this respect.

  Subsequently, when the ECU detects a drop in the vehicle height due to an increase in the load capacity and restores the vehicle height before the increase in the load load, or when an instruction intended to increase the vehicle height of the vehicle occupant is received, When it is necessary to raise the vehicle height, for example, when it is necessary to raise the vehicle height according to the attitude control, the ECU drives or stops the compressor 2 and applies the solenoid 8d to connect the charge valve 8 to the communication position. The control valve 14 is switched to the communication position 14a by applying the solenoid 14d in the control valve 14 immediately before the air spring A to which compressed air is to be supplied, among the four air springs A, and the other switching valve 4 and the exhaust. The valve 21 is controlled so as to take the cutoff positions 4b and 21b without energizing.

  In order to raise the vehicle height uniformly, all the control valves 14 are switched to the communication position 14a. However, there are imbalances in the distribution of the load weight or when the vehicle is turning and the posture should be controlled. For example, when the vehicle height of only one side is raised in the vehicle traveling direction of the vehicle, the compressed air may be supplied only to the air spring A disposed on the vehicle height raising side. Only the control valve 14 corresponding to the air spring A to be switched is switched to the communication position 14a.

  When the vehicle height rises, compressed air is supplied from the high pressure tank 7 or from the compressor 2 in addition to the high pressure tank 7 into the air chamber G of the air spring A to be supplied with compressed air, and the pressure in the air chamber G increases. As a result, the air spring A extends and the vehicle height rises. When the ECU determines that the vehicle height reaches the target vehicle height by supplying compressed air from the high-pressure tank 7, the ECU 2 does not drive the compressor 2, and basically the compressor 2 is driven. The high pressure tank usage ascending mode is employed in which the supply of compressed air from the high pressure tank 7 is prioritized over the supply of compressed air by That is, when the vehicle height does not reach the target vehicle height when the compressed air is supplied from the high-pressure tank 7, first, the high-pressure tank usage ascending mode is adopted to supply the compressed air from the high-pressure tank 7, and then the charge valve 8 is switched to the shut-off position 8b, and the compressor use ascending mode for supplying the compressed air to the air spring A by driving the compressor 2 is adopted. In addition, when switching to the supply of compressed air from the compressor 2, the charge valve 8 may be maintained at the communication position 8a. However, the speed of raising the vehicle height by the amount charged to the high-pressure tank 7 is reduced. Switching the charge valve 8 to the cutoff position 8b is more efficient in terms of raising the vehicle height. That is, when the vehicle height rises, the vehicle height is raised by switching only from the high pressure tank use rise mode or from the high pressure tank use rise mode to the compressor use rise mode.

  In addition, when the pressure of the high-pressure tank 7 lowered by the vehicle height rises below the high-pressure tank lower limit value, the above-described pressure accumulation operation is performed to accumulate the high-pressure tank 7.

  Furthermore, when the ECU detects an increase in the vehicle height due to a decrease in the loaded load and restores the vehicle height before the decrease in the loaded load, or when a command intended to lower the vehicle height of the vehicle occupant is received, The ECU stops the compressor 2 when it is necessary to lower the vehicle height, such as when it is desired to lower the vehicle height when entering or leaving the vehicle, or when it is determined that the vehicle height needs to be lowered according to attitude control. The switching valve 4 is switched to the communication position 4a by being applied to the solenoid 4d, and the solenoid 14d in the control valve 14 immediately before the air spring A from which the compressed air is to be exhausted is applied among the four air springs A. Is switched to the communication position 14a, and the other charge valve 8 and exhaust valve 21 are not energized, and control is performed so that they take off positions 8b and 21b, respectively.

  In order to lower the vehicle height uniformly, all the control valves 14 are switched to the communication position 14a. However, there is a bias in the distribution of the load weight or when the vehicle is turning and the posture control should be performed. For example, when the vehicle height of only one side is lowered in the vehicle traveling direction of the vehicle, the compressed air may be exhausted only from the air spring A disposed on the vehicle height lowering side. Only the control valve 14 corresponding to the air spring A to be switched is switched to the communication position 14a.

  Then, the compressed air is exhausted from the air chamber G of the air spring A to be exhausted, passes through the switching valve 4 and is supplied to the low pressure tank 9 through the loop line 3, while the air spring A to be exhausted is supplied. As the pressure in the air chamber G decreases, the air spring A contracts and the vehicle height drops. When the pressure in the low-pressure tank 9 reaches the upper limit value of the low-pressure tank due to the pressure accumulation in the low-pressure tank 9 due to the exhaust of the air spring A, the ECU drives the compressor 2 and applies the solenoid 21d to the exhaust valve. 21 is set as a communication position 21 a, and the compressed air in the air chamber G is released to the atmosphere via the loop line 3, the compressor 2 and the exhaust line 20.

  As described above, when the pressure in the low-pressure tank 9 exceeds the pressure in the high-pressure tank 7 when accumulating in the low-pressure tank 9, the high-pressure tank 7 is accumulated via the recycle line 15. The compressed air exhausted from G can be recovered not only by the low-pressure tank 9 but also by the high-pressure tank 7, and the energy consumption in the air circuit 1 can be further reduced.

  When exhausting from the air chamber G as described above, it is first determined whether or not pressure accumulation in the low-pressure tank 9 is necessary, that is, if the pressure in the low-pressure tank 9 is below the upper limit value of the low-pressure tank, the control valve 14 and the opening of the loop line 3 by the switching valve 4 and the low-pressure tank accumulating mode for accumulating the low-pressure tank 9 by the opening of the switching valve 4, there is no need, that is, the low-pressure tank 9 has already been sufficiently accumulated and the pressure is low When the tank upper limit value is reached or after the low pressure tank 9 is sufficiently accumulated in the low pressure tank accumulating mode and reaches the low pressure tank upper limit value, the control valve 14 opens the supply line 5 and the switching valve. 4, in addition to opening the loop line 3, the compressor 2 is driven and the exhaust valve 21 is set to the communication position 21 a so that the compressed air in the air chamber G is supplied. When the vehicle height down to mind open will be moved to the open-to-atmosphere mode. That is, when the vehicle height is lowered, basically, the vehicle height is lowered by selecting two modes of the low pressure tank pressure accumulation mode and the air release mode when the vehicle height is lowered.

  When the desiccant of the dryer 11 becomes saturated and is dried, the ECU appropriately adopts a tank atmosphere release mode in which the compressed air is exhausted from the high-pressure tank 7 to release the compressed air to the atmosphere, or the air is appropriately aired. By adopting an air chamber atmosphere release mode in which the compressed air is released to the atmosphere by exhausting from the chamber G, the dried compressed air is appropriately passed through the dryer 11 to dry the desiccant of the dryer 11.

  In the tank atmosphere release mode and the air chamber atmosphere release mode, the compressed air exhausted from the high-pressure tank 7 or the air chamber G passes through the throttle 12, and the exhaust flow is given resistance by the throttle 12 and the exhaust speed is increased. Therefore, the air is slowly passed through the dryer 11 while the pressure is rapidly reduced and dried, so that the dryer 11 is effectively dried.

  In the tank atmosphere release mode, only the charge valve 8 and the exhaust valve 21 are switched to the communication positions 8a and 21a, and the compressor 2, the switching valve 4 and the control valve 14 are not driven and switched to the communication positions 4a and 14a. .

  Further, in the air chamber atmosphere release mode, the control valve 14 and the exhaust valve 21 are simply switched to the communication positions 14a and 21a, and the compressor 2, the switching valve 4 and the charge valve 8 are driven and switched to the communication positions 4a and 8a. Absent.

  Cases in which this air chamber open-to-air mode is adopted include, for example, when the vehicle speed rises and the vehicle height is lowered, or when the vehicle height is lowered by adjusting the vehicle height with respect to load fluctuations. There may be cases where it is good to be slow.

  The operation of the air circuit 1 of the present embodiment has been described above. However, in the air circuit 1 of the present embodiment, the charge valve 8 and the switching valve 4 in the air circuit 1 are highly poppet type on-off valves. Therefore, there is no fear of air leakage and no air leakage to the atmosphere, so no energy loss occurs.

  In addition to not causing energy loss due to air leakage, it is possible to reduce the compression ratio of air by the compressor 2 by accumulating the low-pressure tank 9 and to avoid constant driving of the compressor 2 by providing the high-pressure tank 7. Therefore, the energy consumption of the air circuit 1 is further reduced as compared with the conventional air circuit.

  Further, since the charge valve 8 and the switching valve 4 in the air circuit 1 are two-port and two-position poppet type opening / closing valves with high sealing performance, the valve structure is simple and a spool valve must be used. Since the dimensional control valve is not forced to have high-precision dimensional control and the valve itself can be made smaller than the direction switching valve, the manufacturing cost of the air circuit 1 is reduced and the air circuit is reduced. It becomes possible to improve the mountability to the vehicle by saving the entire space of 1.

  Further, the vehicle height is raised and lowered, the pressure is accumulated in the high-pressure tank 7 and the low-pressure tank 9, the compressed air in the high-pressure tank 7 and the air spring A is released into the atmosphere, the dryer 11 is dried, and the air spring A provided on each wheel. All the valve elements in the air circuit 1 are the charge valve 8, the switching valve 4, the control valve 14, and the exhaust valve 21 while satisfying all functions necessary for control. Can be reduced as compared with the conventional air circuit.

  Further, in the air circuit 1 of the present embodiment, when the pressure in the low pressure tank 9 exceeds the pressure in the high pressure tank 7 when exhausting from the air spring A and accumulating the low pressure tank 9, the recycle line 15 Since the pressure of the high pressure tank 7 can be accumulated by the exhaust of the air spring A through the exhaust, the exhaust of the air spring A can be reused for raising the vehicle height, the operating rate of the compressor 2 can be further reduced, and the energy consumption can be further reduced. It becomes possible to reduce.

  Furthermore, in the air circuit 1 of the present embodiment, a suction line 17 that is capable of sucking the air provided in the middle of the loop line 3 and between the low-pressure tank 9 and the suction port 2b of the compressor 2, Since the check valve 19 that allows only the flow from the atmosphere side to the loop line 3 side provided in the middle of the line 17 is provided, the selection of the suction destination of the compressor 2 is reversed between the low-pressure tank 9 side and the atmosphere side. Since it is possible to select automatically by the stop valve, it is not necessary to control the suction from the low-pressure tank 9 and the suction from the atmosphere by the direction switching valve, and also in this respect, the energy consumption in the air circuit 1 is suppressed. Can do.

  Further, a check valve 10 and a dryer that allow only a flow from the upstream side to the downstream side in order from the upstream to the discharge port 2a of the compressor 2 in the middle of the loop line 3 and upstream from the charge line 6 and the supply line 5. 11, an exhaust line 20 that can open the atmosphere between the check valve 10 of the loop line 3 and the dryer 11 is provided, and a poppet electromagnetic switching exhaust valve 21 that opens and closes the exhaust line 20 in the middle of the exhaust line 20. Therefore, the dryer 11 can be dried by the exhaust from the air spring A and the high-pressure tank 7, and the exhaust line 20 is sealed with the exhaust valve 21 closed. Air leakage from the circuit 1 is prevented.

  Further, since the poppet electromagnetic switching control valve 14 for opening and closing the supply line 5 is provided in the middle of the supply line 5, the air chamber G of the air spring A is securely sealed, and the air circuit 1 is not driven. A change in vehicle height can be reliably prevented.

  In addition, since the charge valve 8, the switching valve 4, the control valve 14, and the exhaust valve 21 are set to close each line when not energized and open each line by energization, Even if a situation in which energization becomes impossible occurs, the loop line 3, the charge line 6, the supply line 5, and the exhaust line 20 of the air circuit 1 are automatically closed, so that the air chamber G of the air spring A is locked. Thus, it is possible to maintain the vehicle height and reliably shift to the fail-safe mode.

  This is the end of the description of the present invention, but it goes without saying that the scope of the present invention is not limited to the details shown or described.

It is the figure which showed the air circuit in one embodiment of this invention. It is the list | wrist which showed the operation mode of the air circuit in one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air circuit 2 Compressor 2a Discharge port 2b in compressor Compressor suction port 3 Loop line 4 Switching valve 4a Communication position 4b in switching valve Shut-off position 4c in switching valve Spring 4b in switching valve Solenoid 5 in switching valve 5 Supply line 6 Charge line 7 High pressure tank 8 Charge valve 8a Communication position 8b in charge valve Cut off position 8c in charge valve Spring 8b in charge valve Solenoid 9 in charge valve Low pressure tank 10, 13, 16, 19 Check valve 11 Dryer 12 Throttle 14 Control valve 14a Control valve Communication position 14b at control valve Shut-off position 14c Control valve spring 14b Control valve solenoid 15 Recycle line 17 Suction line 18 Filter 20 Drain Air line 21 Exhaust valve 21a Communication position 21b at exhaust valve Cut off position 21c at exhaust valve Spring 21b at exhaust valve Solenoid 30, 31 at exhaust valve Pressure sensor A Air spring C Chamber D Damper E Diaphragm G Air chamber M Motor R Rod S Cylinder

Claims (4)

In an air circuit for supplying and discharging compressed air to an air spring interposed between a vehicle body and an axle, a loop line connecting a compressor, a discharge line and a suction side of the compressor, and a loop line provided in the middle of the loop line A poppet type electromagnetic switching valve that opens and closes, a supply line that connects the discharge side of the compressor and the air spring in the middle of the loop line, and a compressor discharge from the switching valve that is in the middle of the loop line A high-pressure tank connected to the side via a charge line, a poppet type electromagnetic switching type charge valve provided in the middle of the charge line to open and close the charge line, and a compressor suction from the switching valve in the middle of the loop line a low-pressure tank is connected to the side of the compressor from the switching valve in the middle of the loop line suction side and the charge line Features of a recycle line connecting the high-pressure tank side of the charge valve in the middle, that a check valve provided in the middle of the recycle line to allow only flow from the loop line side to the charge line side Air circuit. In the middle of the loop line, between the low pressure tank and the suction side of the compressor, a suction line capable of sucking the atmosphere, and provided in the middle of the suction line, allows only the flow from the atmosphere side to the loop line side. The air circuit according to claim 1 , further comprising a check valve . A check valve and dryer that allow only the flow from the upstream side to the downstream side in order from the upstream side are provided on the discharge side of the compressor that is in the middle of the loop line and upstream from the charge line and supply line. The air according to claim 1 or 2 , wherein an exhaust line that opens the air between the valve and the dryer is provided, and a poppet electromagnetic switching exhaust valve that opens and closes the exhaust line is provided in the middle of the exhaust line. circuit. 4. The air circuit according to claim 1, wherein a poppet electromagnetic switching control valve for opening and closing the supply line is provided in the middle of the supply line .

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