Actuators and fluid control devices

Abstract

To provide an actuator and a fluid control device in which suitable control can be achieved.SOLUTION: An actuator includes a control unit (33) configured to allow a first control capable of driving a drive part (50) with a first driving force and a second control capable of driving the drive part (50) with a second driving force which is stronger than the first driving force, a moving part (60) configured to move in a predetermined direction, an elastic member (40) configured to receive at least one of the first driving force and the second driving force from the drive part (50) and to supply a force for the moving part (60) to move to the moving part (60), and a detection unit (32) configured to supply a detection signal for detecting a stop of the drive part (50) to the control unit (33). The control unit (33) performs the second control when the stop of the drive part (50) is detected after performing the first control.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an actuator and a fluid control device. [Background technology]

[0002] Patent Document 1 describes a stepping motor valve having a valve element 3 supported in a balanced position by springs 8, 8' and washers 9, 9' so that they can move relative to each other in the axial direction. Patent Document 1 also describes that the valve element 3 normally rotates together with the rotor 6, and that when friction between the valve element and valve seat increases, the rotor 6 can continue to rotate while the rotation of the valve element 3 remains stopped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 01-098777 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved is to provide an actuator and a fluid control device that can achieve suitable control. [Means for solving the problem]

[0005] An actuator according to a first aspect of the present invention comprises: a control unit that can perform a first control that can drive the drive unit with a first drive force and a second control that can drive the drive unit with a second drive force stronger than the first drive force; a moving unit that is attached to a valve body of a valve device and can move in a predetermined direction; an elastic member that receives at least one of the first drive force and the second drive force from the drive unit and can supply to the moving unit a force for moving the moving unit; a storage unit that stores retightening amount information corresponding to a retightening amount for retightening the valve body to strongly press it against a contact portion of the valve device to limit the amount of fluid flowing through the valve device; and a position detection unit that detects a position of the drive unit, wherein the first drive force is a drive force that cannot contract the elastic member and the second drive force is a drive force that can contract the elastic member, and under the first control, the drive unit can be driven until the valve body and the contact portion come into contact, and the valve body and the contact portion come into contact with each other, and therefore the drive unit stops driving because the elastic member cannot be contracted, and in the second control, even after the valve body and the contact portion come into contact with each other, the drive unit can be driven while the elastic member is contracted, and the control unit stores in the storage unit first position information corresponding to the position when the valve body and the contact portion come into contact with each other and the drive unit driving by the first control stopped, and drives by the second control the drive unit by a distance corresponding to the retightening amount information in the direction in which the drive unit was driven by the first control and stops it, and stores in the storage unit second position information corresponding to the position when the drive unit was driven by the second control by a distance corresponding to the retightening amount information and stopped, and in normal control, the valve is retightened by driving the drive unit by the second control using the second position information stored in the storage unit. . [Effects of the Invention]

[0006] According to the present invention, it is possible to provide an actuator and a fluid control device that can realize suitable control. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. 1 is a diagram for explaining a fluid control device according to a first embodiment. [Figure 2] FIG. 2 is a diagram for explaining the actuator of the first embodiment. [Figure 3] FIG. 3 is a diagram for explaining the circuit of the actuator of the first embodiment. [Figure 4] FIG. 4 is a diagram for explaining the operation of the actuator of the first embodiment. [Figure 5] FIG. 5 is another diagram for explaining the operation of the actuator of the first embodiment. [Figure 6] FIG. 6 is yet another diagram for explaining the operation of the actuator of the first embodiment. [Figure 7] FIG. 7 is a diagram for explaining the operation of the fluid control device of the first embodiment. [Figure 8] FIG. 8 is a diagram for explaining a fluid control device according to the second embodiment. [Figure 9] FIG. 9 is a diagram for explaining the operation of the actuator of the second embodiment. [Figure 10] FIG. 10 is another diagram for explaining the operation of the actuator of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment)

[0009] FIG. 1 is a diagram for explaining a fluid control device of the first embodiment, FIG. 2 is a diagram for explaining an actuator of the first embodiment, and FIG. 3 is a diagram for explaining a circuit of the actuator of the first embodiment.

[0010] 1, a fluid control device 1 is a device that controls the flow rate of a fluid, such as a liquid such as water or oil, or a fluid such as powder. The fluid control device 1 has an actuator 2 and a valve device 3.

[0011] The actuator 2 is, for example, an electric actuator. The actuator 2 has a case 70, an elastic part 40, a driving part 50, and a moving part (driving shaft) 60.

[0012] The valve device 3 has a connection part 75 connected to the actuator 2, a valve element 76 connected to the connection part 75, a scale 761, a mark 762, and a pipe part 77 through which a fluid 78 flows. A contact part 771 is provided on the +X direction side of the pipe part 77.

[0013] The fluid control device 1 drives the actuator 2, thereby moving the end 611 of the actuator 2 in the +X direction or the −X direction. When the end 611 of the actuator 2 moves in the +X direction or the −X direction, the connection portion 75 and the valve body 76 of the valve device 3 also move in the +X direction or the −X direction.

[0014] Scale 761 is provided on the side surface of valve element 76 along the X direction. Mark 762 is provided opposite scale 761 so that the relative position with respect to pipe portion 77 does not change. Therefore, the user can know the position of valve element 76 in the X direction by reading scale 761 that corresponds to mark 762.

[0015] When controlling the valve device 3 in the opening direction, the actuator 2 moves the end portion 611 in the −X direction, and the valve element 76 moves in the −X direction. This widens the flow path of the pipe portion 77, and the flow rate of the fluid 78 flowing through the valve device 3 increases.

[0016] When controlling the valve device 3 in the closing direction, the actuator 2 moves the end portion 611 in the +X direction, and the valve element 76 moves in the +X direction. This narrows the flow path of the pipe portion 77, reducing the flow rate of the fluid 78 flowing through the valve device 3. The fluid control device 1 can move the actuator 2 in the +X direction until the valve element 76 moves to position 76a and the valve element 76 comes into contact with the contact portion 771 of the pipe portion 77.

[0017] Next, the configuration of the actuator 2 will be described in detail with reference to FIGS.

[0018] 2 and 3, the actuator 2 has a case 70, an elastic part 40, a drive part 50, a moving part (drive shaft) 60, an operation part 31, a detection part 32, a control part 33, and a mechanism part 34. In Fig. 2, the case 70 houses circuits such as the control part 33, the mechanism part 34, part of the drive part 50, etc.

[0019] 2 and 3, the operation unit 31 is provided, for example, on the outside of the case 70, and has a plurality of operation buttons (not shown) that can be operated by the user, and an input unit to which an external control signal is supplied from an external device (not shown). The operation unit 31 outputs an operation signal S1 in response to an operation of the operation buttons by the user or an external control signal.

[0020] The detection unit 32 is, for example, a sensor for detecting the operation (driving), stoppage, etc. of the drive unit 50. The detection unit 32 is, for example, a position detection sensor such as a potentiometer or an encoder. The detection unit 32 may be a sensor that detects linear movement or a sensor that detects rotation. In this embodiment, the detection unit 32 is a potentiometer that detects linear movement. The detection unit 32 is fixed to the case 70, and detects the movement of the drive unit 50 using a brush (not shown) that slides on the drive unit 50, and outputs a detection signal S2. The detection signal S2 is stored in the memory unit 35 of the control unit 33.

[0021] The control unit 33 has, for example, a microcomputer (not shown) and a storage unit 35. The control unit 33 determines (detects) whether the drive unit 50 has stopped based on the detection signal S2. The control unit 33 performs calculations using the operation signal S1 output from the operation unit 31, the detection signal S2 output from the detection unit 32, and information stored in the storage unit 35, and outputs a control signal S3. In this embodiment, the control unit 33 performs first control, second control, and normal control, which will be described later.

[0022] The mechanism unit 34 has a motor (not shown) and a cam mechanism (not shown). The motor may be, for example, a rotating motor or a linearly driven motor. The motor may be a DC motor, an AC motor, a stepping motor, an ultrasonic motor, or the like. For example, in this embodiment, a stepping motor is used to achieve high precision and high torque.

[0023] The cam mechanism may have any configuration. For example, it may be one that converts between rotary drive and linear drive, one that converts rotary drive to rotary drive, one that converts linear drive to linear drive, or one that converts rotary drive to linear drive while rotating. For example, in this embodiment, a cam mechanism is used that converts the rotary drive of the motor into linear drive (+X direction or −X direction).

[0024] In this embodiment, the mechanism unit 34 drives the motor based on the control signal S3, and the driving force of the motor is supplied to the cam mechanism. The cam mechanism uses the supplied driving force to drive the drive unit 50 with a predetermined driving force.

[0025] In FIG. 2, the driving unit 50 has a base 51 extending in the X direction, an end 511 which is the end of the base 51 on the +X direction side, a first protrusion 531 extending in the -Y direction from the portion of the base 51 on the +X direction side, and a second protrusion 532 extending in the -Y direction from the portion of the base 51 on the -X direction side.

[0026] The moving unit 60 has a base 61 extending in the X direction, an end 611 which is the end of the base 61 on the +X direction side, a scale 612 provided on the surface facing the driving unit 50, a second protrusion 632 extending in the Y direction from a portion of the base 61 on the -X direction side, and a first protrusion 631 extending in the Y direction from a portion of the base 61 on the +X direction side of the second protrusion 632.

[0027] 3, the elastic part 40 has an elastic body 41, a support member 45 provided on one end side of the elastic body 41, and a support member 46 provided on the other end side of the elastic body 41. The elastic body 41 is an elastic member such as a metal spring or rubber, for example.

[0028] The support member 45 is provided on the −X direction side of the first protrusions 531 and 631 so as to be able to come into contact with at least one of the first protrusions 531 and 631. The support member 46 is provided on the +X direction side of the second protrusions 532 and 632 so as to be able to come into contact with at least one of the second protrusions 532 and 632.

[0029] In this embodiment, the natural length x 10 [mm] (not shown) of the elastic body 41 is longer than the distance between the first protrusion 531 and the second protrusion 532, or the distance between the first protrusion 631 and the second protrusion 632. Therefore, the elastic body 41 applies pressure to the support members 45 and 46 with an elastic force in a direction that widens the distance between the support members 45 and 46.

[0030] Next, the operation of the actuator will be described with reference to Figures 4 to 6, which are diagrams for explaining the operation of the actuator of the first embodiment.

[0031] 4(a) is a diagram showing an initial state. In the initial state of this embodiment, the first protrusions 531 and 631 are positioned opposite each other, and the second protrusions 532 and 632 are positioned opposite each other. The support member 45 is supported by the first protrusions 531 and 631, and the support member 46 is supported by the second protrusions 532 and 632.

[0032] 4(a), the control unit 33 does not output a control signal S3 for driving the drive unit 50, and the drive unit 50 is stopped. The detection unit 32 outputs a detection signal S2 to the control unit 33, and the control unit 33 stores position information of the drive unit 50 in the memory unit 35 based on the detection signal S2.

[0033] The elastic body 41 is compressed by the first protrusions 531 and 631 and the second protrusions 532 and 632, and has a length of x11 [mm]. In the state shown in Fig. 4(a), the elastic body 41 is shrunk by (x10-x11) [mm] from its natural length of x10 [mm].

[0034] 4(a), the elastic body 41 is sandwiched between the first protrusion 531 and the second protrusion 532. Therefore, the elastic body 41 is compressed by a force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41) to a length of x11 [mm], and generates an elastic force equal to the force F0. Note that if the spring constant of the elastic body 41 is k1 [N / mm], then the force F0 = k1 × (x10 - x11) [N].

[0035] 4(a), the end 511 of the driving part 50 is at the 0 (zero) position on the scale 612 of the moving part 60. This position is called the first position.

[0036] 4(b) shows a state in which the driver 50 has been driven in the +X direction with a first driving force from the state shown in FIG. 4(a). The controller 33 outputs a control signal S3 for driving the driver 50 in the +X direction with the first driving force, and the driver 50 drives in the +X direction with the first driving force. The detector 32 outputs a detection signal S2 to the controller 33, and the controller 33 stores position information of the driver 50 in the memory 35 based on the detection signal S2.

[0037] The first driving force is, for example, a force smaller than force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41). The first driving force is preferably, for example, equal to or smaller than force F0 and equal to or larger than 1 / 20 of force F0. More preferably, the first driving force is, for example, equal to or smaller than force F0 and equal to or larger than 1 / 10 of force F0.

[0038] Until the valve body 76 (see Figure 1) comes into contact with the contact portion 771 (see Figure 1) of the tube portion 77, the first driving force of the driving portion 50 is transmitted to the moving portion 60 via the elastic portion 40, and the driving portion 50 and the moving portion 60 move in the +X direction, and the valve body 76 moves in the +X direction.

[0039] 4(a) by a distance a1 in the +X direction, and when the valve body 76 comes into contact with the contact portion 771, the moving portion 60 receives a resistance from the contact portion 771 and is unable to move. Since the first driving force is equal to or less than force F0 and the elastic portion 40 does not contract, the driving portion 50 is also unable to move. At this time, the detection portion 32 outputs a detection signal S2 to the control portion 33, and the control portion 33 stores the position information of the driving portion 50 in the memory portion 35 as a first reference position based on the detection signal S2.

[0040] In addition, in Figure 4(b), the elastic body 41 is not contracted (the length of the elastic body 41 is x11), so the end 511 of the drive unit 50 is at the 0 (zero) position (first position) of the scale 612 of the moving unit 60.

[0041] Figure 5(a) shows the same state as Figure 4(b). Figure 5(b) shows the state after the drive unit 50 has been driven in the +X direction by a second drive force from the state shown in Figure 5(a).

[0042] 5(b), the control unit 33 outputs a control signal S3 to drive the drive unit 50 in the +X direction with the second driving force, and the drive unit 50 is driven in the +X direction with the second driving force. The second driving force is, for example, a force greater than force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41). The detection unit 32 outputs a detection signal S2 to the control unit 33, and the control unit 33 stores position information of the drive unit 50 in the memory unit 35 based on the detection signal S2.

[0043] Because the valve body 76 and the contact portion 771 are in contact with each other, the moving portion 60 is (almost) unable to move in the +X direction. Therefore, when the driving portion 50 is driven in the +X direction by the second driving force, the elastic body 41 is compressed. The second driving force is transmitted to the moving portion 60 via the elastic portion 40, and the moving portion 60 presses the valve body 76 and the contact portion 771 even more firmly (re-tightening).

[0044] 5(a) in the +X direction, the control unit 33 determines that a second control termination condition (the distance by which the drive unit 50 is moved by the second control is a2 [mm]) described below is satisfied, and stops the drive unit 50. At this time, the control unit 33 stores the position information of the drive unit 50 in the memory unit 35 as a second reference position based on the detection signal S2.

[0045] 5(b), the drive unit 50 moves a2 [mm] with the second drive force, and the length of the elastic body 41 becomes x12 [mm], which is shorter than x11 [mm]. In this embodiment, x11 [mm] = x12 + a2 [mm], and an elastic force F1 = k1 × (x10 - x12) [N] is generated in the elastic body 41.

[0046] The second driving force is preferably, for example, equal to or less than the rated driving force during normal control of the motor of the mechanism unit 34, and equal to or greater than the force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41). More preferably, the second driving force is, for example, equal to or less than the rated driving force during normal control of the motor, and equal to or greater than twice the force F0.

[0047] 5(b), the elastic body 41 has been shortened by a2 [mm], so the end 511 of the drive unit 50 has moved 2 (two graduations) in the +X direction from the 0 (zero) position on the scale 612. This position is referred to as the second position.

[0048] Figure 6(a) is a diagram illustrating a state similar to that of Figure 4(b). In the fluid control device 1 shown in Figure 6(a), the position of the moving unit 60 is fixed using an external member (not shown) in the state of Figure 4(a). With the position of the moving unit 60 fixed, the control unit 33 performs a first control to drive the drive unit 50 in the -X direction with a third driving force. The third driving force is, for example, a force equal to and opposite to the first driving force. The third driving force is, for example, smaller than the force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41), and therefore the driving unit 50 cannot move. Based on the detection signal S2, the control unit 33 stores the position information of the driving unit 50 in the memory unit 35 as a third reference position. Note that in FIG. 6(a), the end 511 of the driving unit 50 is at the 0 (zero) position (first position) on the scale 612 of the moving unit 60.

[0049] 6(b), the control unit 33 outputs a control signal S3 to drive the drive unit 50 in the −X direction with a fourth drive force, thereby performing second control in which the drive unit 50 drives in the −X direction with the fourth drive force. The fourth drive force is, for example, a force equal in magnitude to the second drive force but directed in the opposite direction.

[0050] 6(a) in the −X direction, the control unit 33 determines that the second control termination condition (the distance by which the drive unit 50 is moved by the second control is −a3 [mm]) is satisfied, and stops the drive unit 50. At this time, the control unit 33 stores the position information of the drive unit 50 in the memory unit 35 as a fourth reference position based on the detection signal S2.

[0051] 6(b), the driving unit 50 is driven by the fourth driving force, so the length of the elastic body 41 is x13 [mm], which is shorter than x11 [mm]. In this embodiment, x11 [mm] = x13 + a3 [mm], and an elastic force F2 = k1 × (x10 - x13) [N] is generated in the elastic body 41.

[0052] 6(b), the elastic body 41 has become shorter by a3 [mm], so the end 511 of the drive unit 50 has moved 2 (two graduations) in the -X direction from the 0 (zero) position on the scale 612. This position is referred to as the third position.

[0053] Next, the operation of the fluid control device will be described with reference to Figure 7. Figure 7 is a diagram for explaining the operation of the fluid control device of the first embodiment.

[0054] As shown in Fig. 7, first, in step 1, the device is installed. In this embodiment, at a site such as a factory, a moving part 60 (see Fig. 1) of the actuator 2 is connected to a connecting part 75 (see Fig. 1) of the valve device 3. In addition, a necessary power source is supplied to the fluid control device 1.

[0055] In step 2, the user performs a predetermined setting using the operation unit 31. The operation unit 31 outputs information about the predetermined setting as an operation signal S1 to the control unit 33. The control unit 33 stores the information about the predetermined setting (operation signal S1) in the storage unit 35.

[0056] Examples of predetermined settings include setting the magnitude of the first driving force, setting the magnitude of the second driving force, setting the magnitude of the third driving force, setting the magnitude of the fourth driving force, setting the second control termination condition, setting the driving force during normal control, etc. Examples of driving force during normal control include the rated driving force during normal control, the maximum driving force during normal control, and the minimum driving force during normal control.

[0057] For example, the magnitude of the first to fourth driving forces may be set as a value corresponding to force [N], or as a value corresponding to pressure [Pa], or as the length [mm] of the elastic body 41 contracted by applying the first to fourth driving forces to the elastic body 41, or as the rotation speed of the motor of the mechanism unit 34, the current supplied to the motor, etc.

[0058] For example, in this embodiment, the natural length x10, length x11 (see FIG. 4(a)), and force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41) of the elastic body 41 are notified to the user in advance. Therefore, the user sets, for example, force F0 × (1 / 10) as the first driving force. For example, in this embodiment, the rated driving force during normal control is set as the second driving force. For example, an integer multiple of force F0 may be set as the second driving force.

[0059] The user can also set a second control termination condition using the operation unit 31. The second control termination condition is an arbitrary condition for terminating the second control. For example, in the present embodiment shown in FIG. 5, "a distance a2 [mm] by which the drive unit 50 is moved by the second control" is set as the second control termination condition.

[0060] The determination of whether the drive unit 50 has moved a distance a2 [mm] may be made, for example, by the control unit 33 detecting the number of rotations of the motor of the mechanism unit 34, or by the control unit 33 monitoring the detection signal S2 of the detection unit 32, or by some other method.

[0061] For example, in this embodiment, a stepping motor is used, so there is a one-to-one correspondence between the rotation speed of the motor and the movement distance of the drive unit 50. Furthermore, when the drive unit 50 moves a distance a2 [mm] during the second control, the elastic body 41 contracts by a2 [mm].

[0062] 5(b), x11 [mm] = x12 + a2 [mm], and when the elastic body 41 contracts by a2 [mm], the length of the elastic body 41 changes from x11 [mm] to x12 [mm], and an elastic force F1 = k1 × (x10 - x12) [N] is generated in the elastic body 41. The elastic force F1 corresponds to the force with which the valve body 76 presses the contact portion 771 when the second control is completed.

[0063] For this reason, the user inputs a desired value corresponding to the elastic force F1=k1×(x10−x12) [N] using the operation unit 31. The operation unit 31 outputs the elastic force F1 to the control unit 33 as an operation signal S1.

[0064] The control unit 33 calculates the movement distance a2 [mm] of the drive unit 50 from the elastic force F1, calculates the number of rotations A [rotations] of the stepping motor to move the drive unit 50 the movement distance a2 [mm], and outputs the number of rotations A [rotations] to the mechanism unit 34 as a control signal S3.

[0065] When the stepping motor of the mechanism unit 34 rotates A times, the drive unit 50 moves a distance a2 [mm], the elastic body 41 contracts a2 [mm], and the valve body 76 presses the contact portion 771 with a force of F1 = k1 × (x10 - x12).

[0066] The setting of the second control termination condition is not limited to the above example. For example, if the user knows the spring constant k1 [N / mm] of the elastic body 41, the user may input the movement distance a2 [mm] of the drive unit 50 using the operation unit 31. In this case, the operation unit 31 generates the movement distance a2 [mm] as the operation signal S1, and the control unit 33 generates the rotation number A [rotations] as the control signal S3, so that the stepping motor of the mechanism unit 34 rotates A [rotations].

[0067] The second control termination condition is not limited to the travel distance of the drive unit 50. For example, the termination condition may be that a predetermined time has elapsed since the start of the second control, that the motor of the mechanism unit 34 has stopped, or that a sensor installed on the valve element 76 or the contact unit 771 has detected that the pressure between the valve element 76 and the contact unit 771 has reached a predetermined value or greater.

[0068] In step 3, the first control is started when the user presses the start button SW1 of the operation unit 31. The first control is, for example, a control for driving the drive unit 50 with a first drive force.

[0069] In the first control, the operation unit 31 outputs an operation signal S1 indicating that the start button SW1 (not shown) has been pressed to the control unit 33. The detection unit 32 outputs a detection signal S2 to the control unit 33. Based on the information stored in the storage unit 35, the control unit 33 generates a control signal S3 to drive the drive unit 50 in the +X direction with a first drive force and outputs the control signal S3 to the mechanism unit 34.

[0070] The mechanism unit 34 drives the motor based on the control signal S3 to drive the drive unit 50 in the +X direction with a first drive force. By driving the drive unit 50 in the +X direction, the moving unit 60 moves in the +X direction, and the valve body 76 (see FIG. 1) approaches the contact portion 771 (see FIG. 1).

[0071] Thereafter, by moving the valve body 76 in the +X direction, the valve body 76 comes into contact with the contact portion 771. When the valve body 76 comes into contact with the contact portion 771, the moving portion 60 cannot move. Because the first driving force is smaller than the force F0, the driving portion 50 cannot compress the elastic body 41, and the movement of the driving portion 50 also stops.

[0072] When the driving unit 50 stops, the control unit 33 detects (determines) that the driving unit 50 has stopped based on the detection signal S2 of the detection unit 32 (step 4).

[0073] In step 5, the control unit 33 stores the position information of the drive unit 50 as a first reference position in the memory unit 35. In this embodiment, the detection signal S2 of the detection unit 32 when the drive unit 50 stops is the first reference position. Note that the end 511 of the drive unit 50 is at the 0 (zero) position (first position) on the scale 612 of the moving unit 60 (see FIG. 4(b)).

[0074] The control unit 33 detects the stop of the drive unit 50, and therefore ends the first control and starts the second control (step 6). The second control is, for example, control to drive the drive unit 50 with a second drive force.

[0075] In the second control, the control unit 33 generates a control signal S3 to drive the drive unit 50 in the +X direction with the second drive force based on the information stored in the memory unit 35, and outputs the control signal S3 to the mechanism unit 34. The mechanism unit 34 drives the motor based on the control signal S3, and drives the drive unit 50 in the +X direction with the second drive force.

[0076] Since the valve body 76 and the moving part 60 cannot move (almost) in the +X direction, the elastic body 41 contracts in response to the movement of the driving part 50. The valve body 76 comes into pressure contact with the contact part 771.

[0077] The control unit 33 repeatedly determines whether the second control termination condition set in step 2 is satisfied. In this embodiment, for example, "a distance a2 [mm] by which the drive unit 50 is moved by the second control (see FIG. 5(b))" is set as the second control termination condition, and therefore the control unit 33 determines whether the second control termination condition is satisfied by repeatedly detecting the number of rotations of the motor of the mechanism unit 34. When the control unit 33 determines that the second control termination condition is satisfied (step 7), it detects the detection signal S2 of the detection unit 32.

[0078] In step 8, the control unit 33 stores, in the storage unit 35, the position information of the drive unit 50 (detection signal S2 of the detection unit 32) when it is determined that the second control end condition is satisfied, as a second reference position.

[0079] After storing the second reference position in the memory unit 35, the control unit 33 stops driving the drive unit 50 and ends the second control. Note that the end 511 of the drive unit 50 is at the +2 position (second position) on the scale 612 of the moving unit 60 (see FIG. 5(b)).

[0080] In step 9, since the second control has ended, the control unit 33 starts normal control. The normal control is, for example, control in which the drive unit 50, the moving unit 60, the valve body 76, etc. are moved using at least one of the first to fourth reference positions.

[0081] In normal control, for example, the operation unit 31 outputs an operation signal S1 based on an external control signal supplied to the input unit of the operation unit 31 or a user's operation of the operation unit 31. The control unit 33 generates a control signal S3 to drive the drive unit 50 based on the operation signal S1, the detection signal S2, and information stored in the storage unit 35, and outputs the control signal S3 to the mechanism unit 34. This allows the valve element 76 to be freely controlled.

[0082] For example, in this embodiment, the control unit 33 performs normal control by setting the second reference position as the closed position of the valve device 3 (a state in which the valve device 3 is closed and the fluid 78 does not flow).

[0083] The normal control may use only one of the first reference position, the second reference position, the third reference position, and the fourth reference position, or may use two or more of the first reference position, the second reference position, the third reference position, and the fourth reference position. For example, when the normal control is performed using the first reference position and the second reference position, the first reference position may be a state in which the fluid 78 hardly flows, and the second reference position may be a state in which the fluid 78 does not flow at all. The fluid control device 1 is provided with a scale 761 and a mark 762, so that in normal control, the user can easily check the open / closed state of the valve device 3 and the operation of the valve element 76 by visually checking the scale 761 and the mark 762.

[0084] The position of the mark 762 relative to the scale 761 can also be detected using a position detection sensor (referred to as a second position detection sensor) such as a potentiometer or an encoder. In this case, the output signal of the second position detection sensor is preferably supplied to the control unit 33. This is because more advanced control can be achieved by using the detection signal S2 (see FIG. 3) output from the above-mentioned detection unit 32 (see FIG. 3) and the output signal of the second position detection sensor.

[0085] The actuator 2 of the present embodiment described above uses at least one of the first reference position, the second reference position, the third reference position, and the fourth reference position, thereby achieving suitable control. The fluid control device 1 can move the valve element 76 to a desired position by controlling the actuator 2.

[0086] The actuator 2 of this embodiment has a driving unit 50 that can be driven by at least one of a first driving force and a second driving force, a moving unit 60 that can move in a predetermined direction, and an elastic unit 40 that receives at least one of the first driving force and the second driving force from the driving unit 50 and supplies the moving unit 60 with a force for moving the moving unit 60.

[0087] As a result, the driving force of the driving unit 50 is supplied to the moving unit 60 via the elastic unit 40, and when the moving unit 60 is stopped, the elastic unit 40 can be compressed by driving the driving unit 50.

[0088] The actuator 2 of this embodiment has a detection unit 32 that supplies a detection signal to the control unit 33 to detect the stop of the drive unit 50, so after performing the first control, the control unit 33 can terminate the first control and start the second control by detecting the stop of the drive unit 50 based on the detection signal from the detection unit 32.

[0089] In this embodiment, the control unit 33 of the actuator 2 is capable of a first control in which the drive unit 50 is driven with a first drive force, and a second control in which the drive unit 50 is driven with a second drive force that is stronger than the first drive force.

[0090] Therefore, the control unit 33 can use the first control to bring the valve body 76 and the contact portion 771 into contact with each other with a weak force, and can use the second control to bring the valve body 76 and the contact portion 771 into pressurized contact with each other with a strong force.

[0091] For example, in this embodiment, since the first driving force is set to a value smaller than the force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41), the contraction amount of the elastic body 41 due to the first control is zero or a very small value. Since the second driving force is set to a value larger than the force F0, the contraction amount of the elastic body 41 due to the second control is a relatively large value.

[0092] In this embodiment, the second control is started from a state in which the valve body 76 and the contact portion 771 are in contact with each other by the first control, and the "amount of movement of the drive portion 50 in the X direction by the second control" can be considered to be equal to the "amount of contraction of the elastic body 41 from the start of the first control to the completion of the second control."

[0093] By multiplying the "amount of contraction of the elastic body 41 from the start of the first control to the completion of the second control" by the spring multiplier k1 [N / mm], the "force (amount of tightening) with which the valve body 76 presses the contact portion 771 at the completion of the second control" is obtained.

[0094] In this embodiment, the user performs a predetermined setting using the operation unit 31, and the control unit 33 supplies a control signal S3 corresponding to the "amount of movement of the drive unit 50 in the X direction by the second control" to the mechanism unit 34 during the second control, thereby realizing the "force (amount of tightening) with which the valve body 76 presses the contact portion 771 when the second control is completed."

[0095] In the fluid control device 1 of this embodiment, the force with which the valve element 76 presses the contact portion 771 (the amount of retightening) can be easily set using the operation unit 31, thereby achieving suitable flow rate control of the fluid 78. For example, even if the suitable amount of retightening (the force with which the valve element 76 presses the contact portion 771) varies depending on the temperature or composition of the fluid 78, the degree of deterioration over time of the valve element 76 and the contact portion 771, or the like, the amount of retightening can be changed using the operation unit 31 to suitably adjust the amount of retightening.

[0096] (Second embodiment)

[0097] Fig. 8 is a diagram for explaining the fluid control device of the second embodiment, Fig. 9 is a diagram for explaining the operation of the actuator of the second embodiment, and Fig. 10 is another diagram for explaining the operation of the actuator of the second embodiment. In the following explanation, the same reference numerals are used to designate the same components as those shown in Figs. 1 to 7, and duplicate explanations will be omitted.

[0098] 8, the fluid control device 1' has an actuator 2 and a valve device 3'. Instead of the connection portion 75, the valve element 76, the scale 761, the mark 762, the fluid 78, the pipe portion 77, and the contact portion 771, the valve device 3' has a connection portion 75a, valve elements 76c, 76e, the marks 761a, 761b, the marks 762a, 762b, the fluids 78a, 78b, the pipe portions 77a, 77b, and the contact portions 771a, 771b.

[0099] Connection portion 75a is connected to valve bodies 76c and 76e. Valve body 76c is provided on the +X direction side of connection portion 75a, and valve body 76e is provided on the -X direction side of connection portion 75a. Scales 761a and 761b are provided on valve bodies 76c and 76e. Marks 762a and 762b are provided opposite scales 761a and 761b. Contact portions 771a and 771b are provided on tube portions 77a and 77b.

[0100] When the actuator 50 is driven in the +X direction, the valve element 76c comes into contact with the contact portion 771a, restricting the flow of the fluid 78a. When the actuator 50 is driven in the -X direction, the valve element 76e comes into contact with the contact portion 771b, restricting the flow of the fluid 78b.

[0101] Since the operations of valve body 76c, scale 761a, mark 762a, fluid 78a, tube portion 77a and contact portion 771a are similar to those of the fluid control device 1 of the first embodiment described above, the following description will focus on the operations of valve body 76e, scale 761b, mark 762b, fluid 78b, tube portion 77b and contact portion 771b.

[0102] 9(a) is a diagram showing an initial state. The control unit 33 is not outputting a control signal S3 for driving the drive unit 50, and the drive unit 50 is stopped. In the state of FIG. 9(a), the end 511 of the drive unit 50 is at the 0 (zero) position (first position) on the scale 612 of the moving unit 60.

[0103] The elastic body 41 has a length of x11 [mm]. If the spring constant of the elastic body 41 is k1, then in the state shown in Fig. 4(a), the elastic body 41 is compressed by a force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41).

[0104] 9(b) shows a state in which the driver 50 has been driven in the -X direction with a third driving force from the state shown in FIG. 9(a). The third driving force is, for example, a force equal to and opposite to the first driving force. The controller 33 outputs a control signal S3 for driving the driver 50 in the -X direction with the third driving force, and starts a first control in which the driver 50 is driven in the -X direction with the third driving force.

[0105] 9(a) in the -X direction by a4, and when the valve body 76e comes into contact with the contact portion 771b, the moving portion 60 receives a resistance from the contact portion 771b and is unable to move. Since the third driving force is equal to or less than the force F0 and the elastic portion 40 does not contract, the driving portion 50 is also unable to move. At this time, the control portion 33 stores the position information of the driving portion 50 in the memory portion 35 as a third reference position based on the detection signal S2 of the detection portion 32.

[0106] In addition, in Figure 9(b), the elastic body 41 is not contracted (the length of the elastic body 41 is x11), so the end 511 of the drive unit 50 is at the 0 (zero) position (first position) of the scale 612 of the moving unit 60.

[0107] Figure 10(a) shows the same state as Figure 9(b). Figure 10(b) shows the state after the drive unit 50 has been driven in the -X direction with a fourth drive force from the state shown in Figure 10(a).

[0108] 10(b), the control unit 33 outputs a control signal S3 for driving the drive unit 50 in the −X direction with a fourth driving force, thereby performing a second control for driving the drive unit 50 in the −X direction with the fourth driving force. The fourth driving force is, for example, a force equal to and opposite to the second driving force. The fourth driving force is, for example, a force greater than force F0 (the force with which the first protrusion 531 and the second protrusion 532 compress the elastic body 41).

[0109] Because valve body 76e and contact portion 771b are in contact, moving portion 60 cannot (almost) move in the -X direction. Therefore, when drive portion 50 drives in the -X direction with the fourth drive force, elastic body 41 is compressed. The fourth drive force is transmitted to moving portion 60 via elastic portion 40, and valve body 76e and contact portion 771b are pressed even more firmly together (re-tightened).

[0110] 10(a) in the −X direction, the control unit 33 determines that the second control termination condition (for example, the distance by which the drive unit 50 is moved by −a5 [mm] under the second control) is satisfied, and stops the drive unit 50. At this time, the control unit 33 stores the position information of the drive unit 50 in the memory unit 35 as a fourth reference position based on the detection signal S2.

[0111] 10(b), the elastic body 41 has been shortened by a5 [mm], and therefore the end 511 of the drive unit 50 has moved a5 (one graduation) in the -X direction from the 0 (zero) position on the scale 612. This position is referred to as the third position.

[0112] The actuator 2 of this embodiment described above has the same configuration as the actuator 2 of the first embodiment, and can therefore achieve the same excellent effects.

[0113] The fluid control device 1' of the present embodiment described above includes an actuator 2 and a valve device 3'. The valve device 3' includes a connection portion 75a, valve bodies 76c and 76e, scales 761a and 761b, marks 762a and 762b, fluids 78a and 78b, tube portions 77a and 77b, and contact portions 771a and 771b.

[0114] Therefore, the control unit 33 can realize suitable control by using at least one of the first reference position, the second reference position, the third reference position, and the fourth reference position. The fluid control device 1' can move the valve bodies 76c and 76e to desired positions by controlling the actuator 2.

[0115] Furthermore, the fluid control device 1′ of this embodiment can realize control to bring the valve body 76c and the contact portion 771a into contact with each other and to pressurize them at a predetermined pressure by driving the drive unit 50 in the +X direction with a first drive force or a second drive force, similar to the operation shown in FIGS. 4 and 5 of the first embodiment, and control to bring the valve body 76e and the contact portion 771b into contact with each other and to pressurize them at a predetermined pressure by driving the drive unit 50 in the −X direction with a third drive force or a fourth drive force, as shown in FIGS. 9 and 10 of the second embodiment.

[0116] The configurations of the above-described embodiments can be combined with each other. Although various embodiments and modifications have been described above, the present invention is not limited to these. For example, combinations of the configurations of the above-described embodiments and other aspects conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention. [Industrial Applicability]

[0117] According to the present invention, it is possible to provide an actuator and a fluid control device that can realize suitable control. [Explanation of symbols]

[0118] 32 Detection unit 33 Control Unit 40 Elastic part 50 Drive unit 60 Moving Part

Claims

1. a control unit capable of a first control for driving the drive unit with a first drive force and a second control for driving the drive unit with a second drive force stronger than the first drive force; a moving part that is attached to a valve body of the valve device and is movable in a predetermined direction; an elastic member that receives at least one of the first driving force and the second driving force from the driving unit and that supplies a force to the moving unit for moving the moving unit; a storage unit configured to store retightening amount information corresponding to a retightening amount for retightening the valve body by strongly pressing the valve body against a contact portion of the valve device in order to limit the amount of fluid flowing through the valve device; A position detection unit that detects a position of the drive unit, the first driving force is a driving force that cannot contract the elastic member, the second driving force is a driving force capable of contracting the elastic member, In the first control, the drive unit can be driven until the valve body and the contact portion come into contact with each other, and after the valve body and the contact portion come into contact with each other, the elastic member cannot be contracted, so that the drive unit stops being driven. In the second control, even after the valve body and the contact portion come into contact with each other, the drive portion can be driven while the elastic member is contracted, The control unit is storing in the storage unit first position information corresponding to a position at which the valve body comes into contact with the contact portion and the drive unit stops being driven under the first control; Drive the drive unit by the second control in the direction in which the drive unit was driven by the first control by a distance corresponding to the additional tightening amount information, and then stop the drive unit. storing second position information in the storage unit, the second position information corresponding to a position when the drive unit is driven and stopped by the second control by a distance corresponding to the additional tightening amount information; In normal control, the actuator further tightens the valve by driving the drive unit through the second control using the second position information stored in the memory unit.

2. A fluid control device using the actuator according to claim 1.

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