Fluid-operated machines

Abstract

To generate small torque during operation start of a fluid operation machine.SOLUTION: A fluid operation machine 1 comprises: cylinder chambers 11 to 14 in which pistons 21 to 24 that rotate a crankshaft 26 reciprocate; valve units 31 to 34 that can switch between an open state in which fluid is supplied from a fluid storage unit 19 to the cylinder chambers 11 to 14 and a closed state in which no fluid is supplied from the fluid storage unit 19 to the cylinder chambers 11 to 14; and a control unit 70 that transitions from the closed state to an intermediate state between the closed state and the open state when the crankshaft 26 starts to rotate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluid-working machine and a valve unit. [Background technology]

[0002] Pump motors mounted on vehicles are used as fluid-operated machines. In the pump motor described in Patent Document 1 below, oil is supplied to a cylinder in which a piston moves in a translatory manner, and the piston rotates a crankshaft, which is a power shaft, to transmit power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-55018 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above technology, when the valve is opened to supply oil from the high pressure chamber to the cylinder, the pressure in the cylinder becomes the same as the pressure in the high pressure chamber, which increases the torque from the power shaft, making it difficult to generate the small torque required, for example, when starting a vehicle.

[0005] SUMMARY OF THE PRESENT DISCLOSURE OF THE PRESENT DISCLOSURE The present invention has been made in consideration of these points, and has an object to generate a small torque when a fluid working machine starts to operate. [Means for solving the problem]

[0006] In a first aspect of the present invention, a fluid-working machine is provided, comprising: a cylinder chamber in which a piston that rotates a power shaft reciprocates inside; a valve unit capable of switching between an open state in which fluid is supplied from a fluid storage portion to the cylinder chamber and a closed state in which the fluid is not supplied from the fluid storage portion to the cylinder chamber; and a control unit that transitions from the closed state to an intermediate state between the closed state and the open state when the power shaft starts to rotate.

[0007] Furthermore, the control unit may repeatedly turn on and off the power supply for operating the valve unit when the power shaft starts to rotate, to transition to the intermediate state.

[0008] In addition, the valve unit may have a main valve that moves between an open position at which it is switched to the open state and a closed position at which it is switched to the closed state, and a sub-valve that blocks or opens a through passage that passes through the main valve, and the control unit may transition to the intermediate state by opening the through passage when the main valve is in the closed position.

[0009] In addition, when the main valve is in the closed state, it is located in the blocked position that blocks the communication portion with the cylinder chamber, and when in the closed state, it is located in the open position that opens the communication portion, and the control unit may transition to the intermediate state by opening the through passage to communicate with the communication portion when the main valve is in the blocked position.

[0010] In addition, the sub-valve may have a movable member that moves relative to the main valve to open and close the through passage, and the control unit may transition to the intermediate state by opening the through passage using the movable member while the main valve is in the closed position.

[0011] In addition, the valve unit may further have a coil that receives electricity to generate a magnetic force that moves the movable member, and the control unit may repeatedly turn electricity on and off to the coil while the main valve is in the closed position, thereby moving the movable member back and forth between a closed position that blocks the through passage and an open position that opens the through passage.

[0012] The actuator may further include a pressure sensor for detecting pressure in the cylinder chamber, and the control unit may control the on / off of the energization based on a detection result of the pressure sensor.

[0013] In addition, the fluid working machine may be mounted on a vehicle, and the control unit may transition the valve unit from the closed state to an intermediate state between the closed state and the open state when the vehicle starts.

[0014] In a second aspect of the present invention, there is provided a valve unit that controls the supply of a fluid supplied from a storage portion to a cylinder chamber, the valve unit having a first flow path connecting to the storage portion, a second flow path connecting to the cylinder chamber, a third flow path between the first flow path and the second flow path, a main valve provided in the third flow path and movable between a blocking position that blocks the third flow path and an opening position that opens the third flow path, a fourth flow path provided in the main valve that connects the first flow path and the second flow path when the main valve is in the blocking position, and a sub-valve that opens or blocks the fourth flow path, wherein a flow resistance of the fourth flow path is higher than a flow resistance of the third flow path.

[0015] The valve unit may also have a control unit that controls the main valve and the sub-valve, and the control unit may operate the valve unit in a first operating mode that switches between a first state in which the fluid flows through the third flow path and a second state in which the main valve is in the closed position and the fourth flow path is closed, and a second operating mode that switches between a third state in which the fluid flows through the fourth flow path and the second state. Effect of the Invention

[0016] According to the present invention, an effect is achieved in that a small torque can be generated when the fluid working machine starts to operate. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a fluid working machine 1 according to one embodiment. [Diagram 2] 2 is a schematic diagram showing the internal configuration of a valve unit 31. FIG. [Diagram 3] 2 is a schematic diagram showing the internal configuration of a valve unit 31. FIG. [Figure 4] 2 is a schematic diagram showing the internal configuration of a valve unit 31. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <Configuration of fluid working machines> A configuration of a fluid working machine according to one embodiment will be described. In the following description, a hydraulic pump motor will be taken as an example of a fluid working machine, but the fluid working machine is not limited to a hydraulic pump motor. A fluid working machine is also called a fluid machine, and is generally a device that converts energy between a fluid and a machine. As the fluid, liquids such as water or oil, or gases such as air or gas are used, and applications such as low-speed rotation and high-speed rotation vary depending on the properties of the fluid, such as density and viscosity.

[0019] 1 is a schematic diagram showing the configuration of a fluid working machine 1 according to one embodiment. The fluid working machine 1 is mounted on a vehicle such as a truck. As an example, the fluid working machine 1 is connected to a transmission of the vehicle and is configured to transmit generated power to driving wheels of the vehicle.

[0020] The fluid working machine 1 has cylinder chambers 11, 12, 13, 14, a supply passage 16, a pressure sensor 18, pistons 21, 22, 23, 24, a crankshaft 26, valve units 31, 32, 33, 34, and a control unit 70. Although four cylinder chambers 11-14 and four pistons 21-24 are provided, the present invention is not limited to this, and the number of cylinder chambers and pistons may be three or five or more.

[0021] The cylinder chambers 11 to 14 are arranged around the crankshaft 26. The four cylinder chambers 11 to 14 are arranged at equal intervals (specifically, at 90 degree intervals) along the circumferential direction.

[0022] The supply path 16 is a flow path that connects a fluid storage section 19 that stores a fluid to the cylinder chambers 11 to 14. Here, the supply path 16 branches so as to supply fluid to the four cylinder chambers 11 to 14. Here, the fluid storage section 19 is a high-pressure chamber that stores high-pressure fluid.

[0023] The pressure sensor 18 detects the pressure inside the cylinder chambers 11 to 14. Here, the pressure sensor 18 is provided in each of the cylinder chambers 11 to 14, and detects the pressure in each of the cylinder chambers 11 to 14.

[0024] The pistons 21 to 24 reciprocate inside the cylinder chambers 11 to 14. As the pistons 21 to 24 reciprocate, the crankshaft 26 with which the pistons 21 to 24 are in contact rotates.

[0025] The crankshaft 26 is a power shaft that transmits power. The crankshaft 26 has a shaft portion 27 and a cam portion 28. Shaft portion 27 is the rotation axis of crankshaft 26. Cam portion 28 is provided eccentrically on the outer periphery of shaft portion 27. Pistons 21-24 contact the outer periphery of cam portion 28. With this configuration, the reciprocating motion of pistons 21-24 is converted into the rotational motion of shaft portion 27 via cam portion 28.

[0026] The valve units 31-34 adjust the flow of fluid from the fluid storage portion 19 to the cylinder chambers 11-14. Each of the valve units 31-34 adjusts the flow of fluid to the corresponding cylinder chambers 11-14. For example, the valve unit 31 adjusts the flow of fluid to the cylinder chamber 11. The valve units 31-34 are provided midway along the path from the supply passage 16 to the cylinder chambers 11-14. The valve units 31-34 are switchable between an open state in which the fluid is supplied from the fluid storage portion 19 to the cylinder chambers 11-14, and a closed state in which the fluid is not supplied from the fluid storage portion 19 to the cylinder chambers 11-14. The detailed configuration of the valve units 31-34 will be described later.

[0027] The control unit 70 controls the overall operation of the fluid working machine 1. For example, the control unit 70 controls the valve units 31-34 to transition between an open state in which fluid is supplied to the cylinder chambers 11-14 and a closed state in which fluid is not supplied to the cylinder chambers 11-14.

[0028] <Detailed configuration of the valve unit> Since the valve units 31 to 34 have the same configuration, the internal configuration of the valve units will be described in detail below by taking the valve unit 31 as an example.

[0029] 2 to 4 are schematic diagrams showing the internal configuration of the valve unit 31. The valve unit 31 has a housing 40, a flow path portion 42, a communication portion 44, a main valve 46, a through passage 48, a first spring 50, a moving member 52, a second spring 54, and a coil 56.

[0030] The housing 40 constitutes the main body of the valve unit 31. A flow path portion 42 and the like are provided inside the housing 40.

[0031] The flow path section 42 is in communication with the supply path 16, and is a flow path through which the fluid flows from the supply path 16 into the flow path section 42. As shown in Figs. 2 to 4, the flow path section 42 is provided so as to penetrate the housing 40. Note that the supply path 16 is connected to both ends in the longitudinal direction of the flow path section 42 shown in Fig. 2 etc. (For ease of explanation, only the inflow from the lower side of the flow path section 42 is shown in Figs. 3 and 4).

[0032] The communication portion 44 communicates with the cylinder chamber 11 and is a flow path through which the fluid in the valve unit 31 flows from the communication portion 44 to the cylinder chamber 11. The communication portion 44 is provided so as to be perpendicular to the flow path portion 42. The width of the communication portion 44 is smaller than the width of the flow path portion 42.

[0033] The main valve 46 is a valve that moves between an open position where the main valve 46 is switched to an open state where the fluid is supplied to the cylinder chamber 11, and a closed position where the main valve 46 is switched to a closed state where the fluid is not supplied to the cylinder chamber 11. Specifically, the main valve 46 is located at a closed position (position shown in FIG. 2) where the communication part 44 is closed, and at an open position (position shown in FIG. 4) where the communication part 44 is opened. When the main valve 46 is located at the open position, the main valve 46 is in an open state where the fluid is supplied to the cylinder chamber 11, and when the main valve 46 is located at the closed position, the main valve 46 is in a closed state where the fluid is not supplied to the cylinder chamber 11. When the main valve 46 is located at the open position, as shown in FIG. 4, the fluid passes through a flow path part 49 that connects the flow path part 42 and the communication part 44, and the fluid is supplied to the cylinder chamber 11. In other words, the main valve 46 is provided in the flow path part 49 (FIG. 4) that connects the flow path part 42 and the communication part 44, and can be said to be a valve that is movable between a closed position where the flow path part 49 is closed and an open position where the flow path part 49 is opened.

[0034] The main valve 46 has a shaft portion 47a and a large diameter portion 47b. The shaft portion 47a is movable in the axial direction along a guide recess 41 of the housing 40. The guide recess 41 is provided on the opposite side to the communication portion 44 as viewed from the flow path portion 42. When the shaft portion 47a moves in the axial direction, the main valve 46 is located at a closed position or an open position.

[0035] The large diameter portion 47b is provided at the tip of the shaft portion 47a, and the diameter of the large diameter portion 47b is larger than the diameter of the shaft portion 47a. The tip surface of the large diameter portion 47b is curved and convex. When the main valve 46 is in the closed position, the tip surface of the large diameter portion 47b closes the communication portion 44 as shown in FIG. 2. On the other hand, when the main valve 46 is in the open position, the tip surface of the large diameter portion 47b is separated from the communication portion 44 as shown in FIG. 4. The large diameter portion 47b is located in a flow path portion 49 (see FIG. 4) in the housing 40. As shown in FIG. 4, the flow path portion 49 is a third flow path located between the flow path portion 42 (first flow path) and the communication portion 44 (second flow path). The large diameter portion 47b closes the flow path portion 49 when the main valve 46 is located in the closed position (see FIG. 2), and opens the flow path portion 49 when the main valve 46 is located in the open position (see FIG. 4).

[0036] The through passage 48 is a fourth flow passage provided to penetrate the main valve 46. Here, the through passage 48 is formed in a T-shape so as to penetrate between the outer circumferential surface of the shaft portion 47a and the tip surface of the large diameter portion 47b. However, the present invention is not limited to this, and the through passage 48 may be formed in an L-shape. The through passage 48 is a flow passage that connects the flow passage portion 42 and the communication portion 44 when the main valve 46 is in the closed position. By providing the through passage 48, for example, even when the main valve 46 is in the closed position, the fluid in the flow passage portion 42 can flow to the communication portion 44 via the through passage 48. The through passage 48 is a narrow flow passage, and the width of the through passage 48 is smaller than the width of the communication portion 44. That is, the flow resistance in the through passage 48 is higher than the flow resistance in the flow passage portion 49 that connects the flow passage portion 42 to the communication portion 44 when the main valve 46 is in the open position.

[0037] The first spring 50 is provided in the guide recess 41. The first spring 50 is a compression spring here, and presses the main valve 46 toward the communication portion 44. The first spring 50 contacts an end face of the shaft portion 47a of the main valve 46 and a bottom surface of the guide recess 41. The first spring 50 presses the main valve 46, so that the main valve 46 is positioned at a closing position where it closes the communication portion 44.

[0038] The moving member 52 is provided so as to be movable relative to the main valve 46. The moving member 52 is a ferromagnetic body, and is movable by the magnetic force generated by the coil 56. Specifically, the moving member 52 is moved in a direction away from the large diameter portion 47b of the main valve 46 by the magnetic force. The moving member 52 is provided so as to surround the shaft portion 47a of the main valve 46, and is movable in the axial direction of the shaft portion 47a. The moving member 52 moves between a closing position (position shown in FIG. 2) where the through passage 48 is closed, and an opening position (position shown in FIG. 3) where the through passage 48 is opened. Thus, the moving member 52 opens and closes the through passage 48.

[0039] The second spring 54 is provided so as to cover the shaft portion 47a of the main valve 46. The second spring 54 is a compression spring here, and presses the moving member 52 toward the large diameter portion 47b. The second spring 54 contacts the side surface of the moving member 52 and the flange portion 47c of the shaft portion 47a. By the second spring 54 pressing the moving member 52, the moving member 52 is positioned at a blocking position where it blocks the through passage 48.

[0040] The coil 56 is provided around the main valve 46. When the coil 56 is energized, a magnetic force is generated around the coil 56, and the moving member 52 is moved by the magnetic force. Specifically, the magnetic force causes the moving member 52 to move from a closed position where the through passage 48 is closed to an open position against the pushing force of the second spring 54. When the energization of the coil 56 is turned off, the moving member 52 returns from the open position to the closed position. In this embodiment, the moving member 52, the second spring 54, and the coil 56 function as a sub-valve that closes or opens the through passage 48 that penetrates the main valve 46.

[0041] Here, an example of the operation of the valve unit 31 when transitioning from a closed state in which no fluid is supplied to the cylinder chamber 11 to an open state in which fluid is supplied to the cylinder chamber 11 will be described. The operation of the valve unit 31 is controlled by the control unit 70. Note that the valve units 32 to 34 also operate in the same manner as the valve unit 31.

[0042] Here, the valve unit 31 is in a closed state. In this case, the main valve 46 is in the closed position as shown in Fig. 2 and closes the communication part 44. Also, since the coil 56 is not energized, the movable member 52 closes the through passage 48. Therefore, the fluid in the flow passage part 42 does not flow into the cylinder chamber 11 through the communication part 44.

[0043] When transitioning from the closed state to the open state, first, electricity is passed through the coil 56. When electricity is passed through the coil 56, a magnetic force is generated by the coil 56. When the magnetic force is generated, the moving member 52 moves against the pushing force of the second spring 54 from the closed position (FIG. 2) where the through passage 48 is blocked to the open position (FIG. 3) where the through passage 48 is opened.

[0044] When the movable member 52 moves to the open position, the through passage 48 is opened, and the fluid in the flow passage portion 42 flows through the through passage 48 to the communication portion 44 (FIG. 3). Then, the fluid that has flowed into the communication portion 44 flows into the cylinder chamber 11.

[0045] Thereafter, pressure is applied to the main valve 46 from the fluid in the communication portion 44, and the main valve 46 moves from the closed position to the open position (FIG. 4) against the pushing force of the first spring 50. When the main valve 46 moves to the open position, the through passage 48 is closed by the moving member 52.

[0046] When the main valve 46 moves to the open position, the communication portion 44 is opened, and the fluid in the flow passage portion 42 flows directly to the communication portion 44 without passing through the through passage 48 (FIG. 4). This makes it easier for the fluid to flow into the cylinder chamber 11, and the pressure in the cylinder chamber 11 can be increased. As the pressure in the cylinder chamber 11 increases, the torque transmitted by the crankshaft 26 also increases.

[0047] The control unit 70 operates the valve units 31 to 34 configured as described above in a first operation mode or a second operation mode. The first operation mode is an operation mode that switches between a first state (open state shown in FIG. 4) in which the fluid flows through the flow path portion 49 and a second state (closed state shown in FIG. 2) in which the main valve 46 is in the closed position and the through passage 48 is closed. The second operation mode is an operation mode that switches between a third state (state shown in FIG. 3) in which the fluid flows through the through passage 48 and the second state.

[0048] In this embodiment, the fluid working machine 1 performs the following control in order to reduce the torque transmitted by the crankshaft 26 when the crankshaft 26 starts to rotate. The reason for reducing the torque is, for example, to prevent a sudden increase in torque and realize a smooth start in a vehicle in which the fluid working machine 1 is provided and the drive wheels are driven by the torque.

[0049] When the crankshaft 26 starts to rotate, the control unit 70 controls the valve units 31-34 to transition from a closed state in which no fluid is supplied to the cylinder chambers 11-14 to an intermediate state between the closed state and the open state. The intermediate state is a state before the open state shown in FIG. 4 is reached. For example, the intermediate state is a state in which the main valve 46 is located in the closed position and the moving member 52 is located in the open position as shown in FIG. 3. In the intermediate state, the fluid in the flow passage portion 42 flows into the cylinder chambers 11-14 through the through passage 48. Therefore, the pressure in the cylinder chambers 11-14 in the intermediate state is smaller than the pressure in the cylinder chambers 11-14 in the open state.

[0050] The control unit 70 transitions to the intermediate state by opening the through passage 48 with the main valve 46 in the closed position. Specifically, the control unit 70 transitions to the intermediate state by opening the through passage 48 with the moving member 52 and communicating with the communication part 44 with the main valve 46 in the closed position. This makes it possible to supply fluid to the cylinder chambers 11-14 without moving the main valve 46.

[0051] When the crankshaft 26 starts to rotate, the control unit 70 repeatedly turns on and off the power supply to operate the valve units 31-34, causing them to transition to an intermediate state. By repeatedly turning on and off the power supply, the control unit 70 causes the state of the valve units 31-34 to transition between the closed state shown in Fig. 2 and the state shown in Fig. 3. In this manner, the intermediate state may refer to a state transitioning between the closed state shown in Fig. 2 and the state shown in Fig. 3.

[0052] The control unit 70, with the main valve 46 in the closed position, repeatedly turns on and off the current to the coil 56, thereby reciprocating the moving member 52 between a closed position where the through passage 48 is closed and an open position where the through passage 48 is opened. Specifically, the control unit 70 reciprocates the moving member 52 between the closed position shown in FIG. 2 and the open position shown in FIG. 3 when the crankshaft 26 starts to rotate. In other words, the control unit 70 repeatedly turns on and off the current to the coil 56 when the crankshaft 26 starts to rotate, thereby repeatedly transitioning between a closed state where no fluid is supplied to the cylinder chambers 11 to 14 and a state where fluid is supplied through the through passage 48. This makes it easier to reduce the amount of fluid in the cylinder chambers 11 to 14 when the crankshaft 26 starts to rotate, and therefore makes it easier to reduce the pressure in the cylinder chambers 11 to 14.

[0053] The control unit 70 may control the on / off of the current supply to the valve units 31-34 based on the detection result of the pressure sensor 18. The control unit 70 switches the current supply to the valve units 31-34 on / off so that the pressure detected by the pressure sensor 18 maintains a predetermined value. For example, when the pressure detected by the pressure sensor 18 exceeds a predetermined value, the control unit 70 lengthens the time for which the current is turned off, thereby controlling the pressure to maintain the predetermined value. This maintains the pressure in the cylinder chambers 11-14 in a state where the crankshaft can generate a predetermined small torque.

[0054] When the crankshaft 26 starts to rotate at the start of the vehicle, the control unit 70 periodically transitions each of the valve units 31-34 between the closed state and the intermediate state. After that, when a predetermined time has elapsed since the start of the vehicle, the control unit 70 periodically transitions each of the valve units 31-34 between the closed state and the open state. As a result, a small torque is transmitted from the crankshaft 26 to the drive wheels of the vehicle immediately after the vehicle starts, and then, when the state transitions from the intermediate state to the open state, a large torque is transmitted to the drive wheels. As a result, the vehicle can be started smoothly.

[0055] <Effects of this embodiment> The fluid working machine 1 of the above-described embodiment has cylinder chambers 11-14 in which pistons 21-24 that rotate the crankshaft 26 reciprocate, and valve units 31-34 that are switchable between an open state in which fluid is supplied to the cylinder chambers 11-14 and a closed state in which fluid is not supplied to the cylinder chambers 11-14. Then, when the crankshaft 26 starts to rotate, the fluid working machine 1 transitions the valve units 31-34 from the closed state to an intermediate state between the closed state and the open state. As a result, when the crankshaft 26 starts to rotate, the amount of fluid flowing into the cylinder chambers 11-14 is small, so the pressure in the cylinder chambers 11-14 does not increase, and as a result, the torque transmitted by the crankshaft 26 is also small.

[0056] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0057] 1 Fluid-operated machines 11~14 Cylinder chamber 18 Pressure Sensor 19 Fluid storage section 21~24 Piston 26 Crankshaft 31~34 Valve unit 46 Main Valve 48 Passage 52 Moving parts 56 Coil 70 Control section

Claims

1. A cylinder chamber in which a piston that rotates a power shaft reciprocates; a valve unit that is switchable between an open state in which fluid is supplied from a fluid storage portion to the cylinder chamber and a closed state in which the fluid is not supplied from the fluid storage portion to the cylinder chamber; a control unit that transitions the closed state to an intermediate state between the closed state and the open state when the power shaft starts to rotate; Equipped with The valve unit includes: a main valve that moves between an open position for switching to the open state and a closed position for switching to the closed state; a sub-valve including a movable member surrounding a shaft portion of the main valve and moving relative to the shaft portion to close and open a through passage passing through the main valve; The control unit causes the main valve to transition to the intermediate state by opening the through passage using the moving member while the main valve is in the closed position. Fluid operated machines.

2. The control unit repeatedly turns on and off the power supply for operating the valve unit when the rotation of the power shaft starts, thereby transitioning the valve unit to the intermediate state.

2. A fluid-working machine according to claim 1.

3. the main valve is located at the closing position to close a communication portion with the cylinder chamber when in the closed state, and is located at the opening position to open the communication portion when in the closed state, The control unit causes the main valve to transition to the intermediate state by opening the through passage and communicating with the communication portion while the main valve is in the closed position.

2. A fluid-working machine according to claim 1.

4. The valve unit further includes a coil that receives current to generate a magnetic force that moves the moving member, The control unit, while the main valve is in the closed position, repeatedly turns on and off the current to the coil to reciprocate the movable member between a closed position at which the through passage is closed and an open position at which the through passage is opened.

2. A fluid-working machine according to claim 1.

5. A pressure sensor for detecting the pressure in the cylinder chamber is further provided. The control unit controls the energization on and off based on a detection result of the pressure sensor. A fluid-working machine according to claim 2.

6. The fluid-working machine is mounted on a vehicle, The control unit transitions the valve unit from the closed state to an intermediate state between the closed state and the open state when the vehicle starts.

2. A fluid-working machine according to claim 1.

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