Electric valve and method for maintaining the valve element position of an electric valve

Abstract

[Task] To provide an electric valve and a method for maintaining a valve element position of the electric valve that is able to prevent a change in a region of a throttle passage and to obtain a desired flow rate characteristic. [Solution] An electric valve (1) includes a valve element (40) which contains a control section (45) having a single conical shape. A stepper motor (66) rotates to move the valve element (40) in a motion section between a valve closed position (Pa) and a fully open position (Pz). When the valve element (40) is in the valve closed position (Pa), a control surface (46), which is an outer circumferential surface of the control section (45), is in contact with a valve seat (16). As the valve element (40) moves out of the valve closed position (Pa) and is in the motion section, a throttling passage is formed between the valve seat (16) and the control surface (46). The motion section includes a first section between the valve closed position (Pa) and a first position, and a second section between the first position and a second position.A controller (80) sets a step angle smaller when the valve element (40) is in the first section than when the valve element (40) is in the second section.

Description

Technical field

[0001] The present invention relates to an electric valve and a method for obtaining a valve element position of the electric valve. Technical background

[0002] Patent document 1 discloses an example of an electric valve according to related technology. The electric valve is installed in a cooling circuit system of an air conditioning system. The electric valve comprises a valve body, a valve element, and a stepper motor for moving the valve element. The stepper motor comprises a rotor and a stator. The rotor rotates in response to pulses input to the stepper motor. The valve element moves along with the rotation of the rotor, and the movement of the valve element changes the flow rate of a fluid (refrigerant) flowing through a valve opening in the valve body. State of the art document (patent document)

[0003] Patent document 1: Japanese unexamined patent application publication no. 2018-179133 Summary of the invention Problem to be solved by the invention

[0004] Fig. Figure 15 presents an example of the valve element of the electric valve according to the related technology. A Fig. The valve element 940 shown in Figure 15 comprises a control section 945 and a seat section 947. Both the control section 945 and the seat section 947 have a conical shape. The cone angle of the control section 945 is smaller than that of the seat section 947. The upper end of the control section 945 is connected to the lower end of the seat section 947. The outer circumferential surface of the control section 945 serves as the control surface 946, which is a conical surface. The outer circumferential surface of the seat section 947 serves as the seat surface 948, which is also a conical surface. A valve body 910 has a valve opening 915 and a valve seat 916. The valve seat 916 is an inwardly conical surface and surrounds the valve opening 915. An inner circumferential edge 916a of the valve seat 916 is connected to an upper end 915a of the valve opening 915.

[0005] When the seat surface 948 is in contact with the inner circumferential edge 916a of the valve seat 916 (i.e., the upper end 915a of the valve opening 915), the valve opening 915 is closed. At this point, the valve element 940 is in a valve-closing position. When the seat surface 948 is separated from the valve seat 916, the valve opening 915 is open, and a throttle passage is formed between the valve element 940 and the inner circumferential edge 916a. Specifically, immediately after the seat surface 948 separates from the valve seat 916, the throttle passage is formed between the seat surface 948 and the inner circumferential edge 916a (a first state). If the seat surface 948 separates further from the valve seat 916, the throttle passage is formed between the control surface 946 and the inner circumferential edge 916a (a second state).

[0006] The graphical representation in Fig. Figure 16 schematically illustrates a relationship between the valve opening degree and the throttle passage area in the electric valve according to the related technology. The valve opening degree specifies a position of the valve element 940 relative to the valve seat 916 (an amount of movement from the valve closing position). The valve opening degree is expressed as a percentage. When the valve element 940 is in the valve closing position, the valve opening degree is 0%, and when the valve element 940 is in a fully open position, the valve opening degree is 100%. The throttle passage area is also expressed as a percentage. When the valve element 940 is in the valve closing position, the throttle passage area is 0%, and when the valve element 940 is in the fully open position, the throttle passage area is 100%.

[0007] As in Fig. As shown in Figure 16, although the dimensions of the valve opening 915, the valve seat 916, and the valve element 940 are within tolerance, some of the electric valves may exhibit a relationship shown by line A, and others may exhibit a relationship shown by line B. Fig. Figure 16 shows a section of line A corresponding to the first state, designated by reference numeral a1, and another section corresponding to the second state, designated by reference numeral a2. A section of line B corresponding to the first state is designated by reference numeral b1, and another section corresponding to the second state is designated by reference numeral b2. In the section of the valve opening degree corresponding to the first state, the difference in magnitudes causes the area of ​​the throttle passage to vary considerably. Thus, the presence of the first state results in a large variation in the area of ​​the throttle passage (i.e., the fluid flow rate) among the electric valves.

[0008] For example, an electric valve with a configuration where a control surface 946 is in contact with a valve seat 916 exhibits not the first state, but only the second, thus preventing variation in the area of ​​the throttle passage. However, to suppress wear of the valve seat 916, a conical shape with a relatively large cone angle is required for the control section 945. Therefore, desired flow rate characteristics cannot be obtained in the electric valve due to the constraints on the shape of the control section 945.

[0009] Accordingly, one object of the present invention is to provide an electric valve and a method for maintaining a valve element position of the electric valve, with which a change in the area of ​​a throttle passage can be prevented and a desired flow rate characteristic can be obtained. Means of solving this problem

[0010] To solve the aforementioned problem, an electric valve according to one aspect of the present invention comprises a valve body having a valve opening and a valve seat enclosing the valve opening, a valve element facing the valve opening, a stepper motor for moving the valve element, and a controller for controlling the stepper motor. The valve element includes a control section having a single conical shape. The stepper motor rotates to move the valve element in a movement section between a valve closed position and a fully open position. When the valve element is in the valve closed position, an outer circumferential surface of the control section is in contact with the valve seat. As the valve element moves from the valve closed position and is in the movement section, a throttling passage is formed between the valve seat and the outer circumferential surface.The motion section comprises a first section between the valve closing position and a first position, and a second section between the first position and a second position that is further away from the valve closing position than the first position. The controller sets one step angle for the stepper motor when the valve element is in the first section and a different step angle when the valve element is in the second section, with the step angles being different from each other.

[0011] In the present invention, the step angle is preferably smaller when the valve element is located in the first section than the step angle when the valve element is located in the second section.

[0012] In the present invention, the stepper motor preferably comprises a magnetic rotor, an A-phase stator, and a B-phase stator. When the valve element is located in the first section, the controller preferably operates the stepper motor in microstepping mode. When the valve element is located in the second section, the controller preferably operates the stepper motor in full-step mode.

[0013] In the present invention, the stepper motor preferably comprises a magnetic rotor, an A-phase stator, and a B-phase stator. When the valve element is located in the first section, the controller preferably sets the excitation mode of the stepper motor to 1-2 phase excitation. When the valve element is located in the second section, the controller preferably sets the excitation mode of the stepper motor to 2 phase excitation.

[0014] To solve the aforementioned problem, a method according to another aspect of the present invention is a method for maintaining a valve element position of an electric valve. The electric valve comprises a valve body having a valve opening and a valve seat enclosing the valve opening, a valve element facing the valve opening, a stepper motor for moving the valve element, and a controller for controlling the stepper motor. The valve element includes a control section having a single conical shape. The stepper motor rotates to move the valve element in a movement section between a valve closed position and a fully open position. A throttle passage is formed between the valve seat and an outer circumferential surface of the control section when the valve element moves from the valve closed position and is in the movement section.The procedure includes a step to obtain two or more combinations of a position of the valve element and a flow rate of a fluid flowing through the valve opening when the valve element is at the position, a step to determine a linear function expression that represents a relationship between the position and the flow rate, based on a design flow rate when the valve element is at the valve closing position, and the combinations, and a step to obtain an actual position of the valve element by using the linear function expression. Advantages of the invention

[0015] In the electric valve according to the present invention, the outer circumferential surface of the control section, which has the only conical shape, is in contact with the valve seat when the valve element is in the valve-closed position. When the valve element moves from the valve-closed position and is in the movement section, the throttle passage is formed between the valve seat and the outer circumferential surface of the control section. Therefore, variation in the throttle passage area can be prevented. Furthermore, the controller sets the step angle for the stepper motor when the valve element is in the first section and sets a different step angle when the valve element is in the second section.Therefore, a desired flow rate characteristic can be obtained by appropriately adjusting the step angles used in the first section and in the second section.

[0016] The method for obtaining the valve element position of the electric valve according to the present invention comprises (1) the step of obtaining two or more combinations of the position of the valve element and the flow rate of fluid flowing through the valve opening when the valve element is in that position, (2) the step of determining the linear function expression representing the relationship between the position and the flow rate, based on the design flow rate when the valve element is in the valve closed position and the combinations thereof, and (3) the step of obtaining the current position of the valve element by using the linear function expression. Consequently, the current position of the valve element can be obtained based on measured flow rates.Therefore, the electric valve can have a configuration in which a stopper mechanism that physically restricts the rotation of the magnetic rotor at the valve closing position is omitted. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a sectional view of an electric valve according to an embodiment of the present invention. [ Fig. 2] Fig. Figure 2 is a sectional view of a stator unit of the electric valve. [ Fig. 3] Fig. Figure 3 is a sectional view of a valve element and elements in its vicinity of the electric valve when the valve element is in a valve closing position. [ Fig. 4] Fig. Figure 4 is a sectional view of the valve element and the elements in its vicinity of the electric valve when the valve element is in a fully open position. [ Fig. 5] Fig. Figure 5 is a graphical representation showing a relationship between a valve opening degree and a flow rate in the electric valve. [ Fig. 6] Fig. Figure 6 is a diagram that shows a positional relationship between a magnetic rotor and a stator of the electric valve. [ Fig. 7] Fig. Figure 7 is a functional block diagram of the electric valve. [ Fig. 8] Fig. Figure 8 is a diagram showing an example of a table relating to pulse count information and step angle information stored in an electric valve controller. [ Fig. 9] Fig. Figure 9 is a diagram that represents a relationship between pulse numbers assigned to intervals between the valve closing position and the fully open position, and positions of the valve element. [ Fig. 10] Fig. Figure 10 is a graphical representation showing an example of a relationship between the position of the valve element and the flow rate of fluid flowing through a valve opening of the electric valve. [ Fig. 11] Fig. Figure 11 is a graphical representation showing another example of the relationship between the position of the valve element and the flow rate of fluid flowing through the valve opening of the electric valve. [ Fig. 12] Fig. Figure 12 is a graphical representation showing yet another example of the relationship between the position of the valve element and the flow rate of fluid flowing through the valve opening of the electric valve. [ Fig. 13] Fig. Figure 13 is a diagram that shows an example of a system for adjusting the electric valve before shipping from the factory. [ Fig. 14] Fig. 14 is a sectional view showing a configuration of a modification of the electric valve in Fig. 1 represents. [ Fig. 15] Fig. Figure 15 is a sectional view of a valve element and elements in its vicinity of an electric valve according to the related technique. [ Fig. 16] Fig. Figure 16 is a graphical representation showing a relationship between a valve opening degree and an area of ​​a throttle passage of the electric valve according to the related technique. Embodiments of the invention

[0017] An electric valve 1 according to an embodiment of the present invention is described below with reference to the Fig. 1 to 13 are described. For example, the electric valve 1 is installed in a cooling circuit system of an air conditioner and operates in response to a command transmitted by a control unit 400 of the air conditioner. The control unit 400 is an external device separate from the electric valve 1.

[0018] Fig. Figure 1 is a sectional view of an electric valve according to the embodiment of the present invention. Fig. Figure 2 is a sectional view of a stator unit of the electric valve. Fig. 3 and Fig. Figure 4 shows sectional views of a valve element and elements in its vicinity of the electric valve. Fig. 3 represents a state in which the valve element is in a valve closing position. Fig. 4 represents a state in which the valve element is in a fully open position. Fig. 1, Fig. 3 and Fig. Figure 4 shows a valve stem and the valve element of the electric valve in front view.

[0019] As in the Fig. 1 and Fig. As shown in Figure 2, the electric valve 1 includes a valve body 10, a can 20, a drive mechanism 30, a valve element 40 and a control unit 80.

[0020] The valve body 10 is made of a metal, such as an aluminum alloy. The valve body 10 includes a body element 11, a flow channel block 12, and a support element 13.

[0021] The body element 11 has a circular cylindrical shape. The body element 11 has a valve chamber 14, a valve opening 15, and a valve seat 16. The valve opening 15 is open towards the valve chamber 14. The valve seat 16 is an inwardly conical surface with an annular shape. The valve seat 16 surrounds the valve opening 15 in the valve chamber 14. An inner circumferential edge 16a of the valve seat 16 is connected to an upper end 15a of the valve opening 15. The body element 11 has a first mounting bore 11a. The first mounting bore 11a is provided in an upper surface 11b of the body element 11.

[0022] The flow channel block 12 has a rectangular parallelepiped shape. The flow channel block 12 has a second mounting bore 12a. The second mounting bore 12a is provided in an upper surface 12b of the flow channel block 12. The body element 11 is arranged in the second mounting bore 12a. The body element 11 is mounted in the flow channel block 12 by means of a screw connection. The upper surface 11b of the body element 11 is flush with the upper surface 12b of the flow channel block 12. Flow channels 17 and 18 are provided in the body element 11 and the flow channel block 12. The flow channel 17 is connected to the valve chamber 14. The flow channel 18 is connected to the valve chamber 14 through the valve opening 15. In the electric valve 1, the flow channel block 12 can be omitted, and the body element 11 can have a rectangular parallelepiped shape.

[0023] The support element 13 has a circular cylindrical shape. The support element 13 is positioned in the first mounting bore 11a. The support element 13 is mounted in the body element 11 by means of a screw connection. The upper part of the support element 13 projects upwards from the upper surface 11b of the body element 11. The support element 13 has an internal thread 13c. The internal thread 13c is located on the inner circumferential surface of the support element 13.

[0024] The can 20 is made of a metal, such as stainless steel. The can 20 has a circular cylindrical shape. The can 20 is open at the bottom and closed at the top. The bottom end of the can 20 is attached to the upper part of the support element 13 via a connecting element 25, which has a circular, plate-like shape.

[0025] The drive mechanism 30 moves the valve element 40 in an up and down direction (one direction of an axis L). The drive mechanism 30 includes a magnetic rotor 31, a valve stem 34, and a stator unit 50.

[0026] The magnetic rotor 31 has a circular cylindrical shape. The magnetic rotor 31 is open at the top and closed at the bottom. The outer diameter of the magnetic rotor 31 is smaller than the inner diameter of the can 20. The magnetic rotor 31 has a plurality of north poles (N) and a plurality of south poles (S). The N poles and the S poles are arranged on the outer circumferential surface of the magnetic rotor 31. The N poles and the S poles extend in the upward and downward directions, respectively. The N poles and the S poles are arranged alternately at regular angular intervals in the circumferential direction. For example, the magnetic rotor 31 has twelve N poles and twelve S poles.

[0027] The valve stem 34 has a circular column shape. The upper end of the valve stem 34 is coaxially attached to the lower end of the magnetic rotor 31. The valve stem 34 has an external thread 34c. The external thread 34c is located on the outer circumferential surface of the valve stem 34. The valve stem 34 is arranged in the support element 13, and the external thread 34c is screwed into the internal thread 13c.

[0028] The valve element 40 is arranged in the valve chamber 14. The valve element 40 faces the valve opening 15 in both the upward and downward directions. The valve element 40 is connected to the lower end of the valve stem 34. For example, the valve stem 34 and the valve element 40 are formed in one piece by cutting a workpiece with a circular column shape.

[0029] The valve element 40 includes a control section 45. The control section 45 has a single conical shape (a frustoconical shape) with a diameter that gradually decreases towards the valve opening 15. In other words, the control section 45 does not have a shape that includes multiple conical shapes with different cone angles. The cone angle of the control section 45 is set to an angle that can suppress wear of the valve seat 16. The cone angle of the control section 45 is preferably set to 30 to 60 degrees. The outer circumferential surface of the control section 45 serves as the control surface 46. The control surface 46 is an outwardly conical surface.

[0030] The valve element 40 is moved in the up and down direction by the drive mechanism 30. The movement of the valve element 40 opens and closes the valve opening 15. In particular, the valve element 40 moves between a Fig. 3 shown valve closing position Pa and one in Fig. The fully open position Pz is shown in Figure 4. A section between the valve closed position Pa and the fully open position Pz serves as a movement section of the valve element 40. In the valve closed position Pa, the control surface 46 is in contact with the inner circumferential edge 16a of the valve seat 16. In the fully open position Pz, the position of a lower end 45a of the control section 45 in the up and down direction coincides with the position of the inner circumferential edge 16a in the up and down direction. As the valve element 40 moves from the valve closed position Pa and is in the movement section, a circular annular gap (a throttle passage) is formed between the inner circumferential edge 16a and the control surface 46. The area of ​​the throttle passage is closely related to the flow rate of fluid flowing through the valve opening 15.

[0031] The graphical representation in Fig. Figure 5 shows the relationship between a valve opening degree and a flow rate in the electric valve 1. The valve opening degree indicates the position of the valve element 40 relative to the valve seat 16 (a measure of movement from the valve closing position Pa) and is expressed as a percentage. When the valve element 40 is at the valve closing position Pa, the valve opening degree is 0%. When the valve element 40 is at the fully open position Pz, the valve opening degree is 100%. The flow rate indicates the rate of flow of fluid through the valve opening 15 and is expressed as a percentage. When the valve element 40 is at the valve closing position Pa, the flow rate is 0%. When the valve element 40 is at the fully open position Pz, the flow rate is 100%. As shown in Fig. As shown in Figure 5, the electric valve 1 (the valve element 40) has a basic flow rate characteristic curve, whereby the flow rate changes linearly according to the valve opening degree. The position of the valve element 40 corresponds to the position of the magnetic rotor 31.

[0032] The internal thread 13c of the support element 13 and the external thread 34c of the valve stem 34 form a screw feed mechanism. When the magnetic rotor 31 is rotated in a valve opening direction, a screw feed action between the internal thread 13c and the external thread 34c moves the valve stem 34 and the valve element 40 upwards. When the magnetic rotor 31 is rotated in a valve closing direction, the screw feed action between the internal thread 13c and the external thread 34c moves the valve stem 34 and the valve element 40 downwards. As the valve element 40 moves downwards and the control surface 46 comes into contact with the inner circumferential edge 16a of the valve seat 16, the valve seat 16 prevents the valve element 40 from moving downwards. The external thread 34c is screwed tightly into the internal thread 13c, thus stopping the screw feed mechanism.Therefore, the rotation of the valve stem 34 and the magnetic rotor 31 is restricted in the valve closing direction.

[0033] The stator unit 50 includes a stator 60 and a housing 70.

[0034] The stator 60 has a circular cylindrical shape. The stator 60 comprises an A-phase stator 61, a B-phase stator 62, and a resin-based form element 63.

[0035] The A-phase stator 61 includes a plurality of claw-type pole teeth 61a and 61b around its inner circumference. The tips of the pole teeth 61a point downwards, and the tips of the pole teeth 61b point upwards. The pole teeth 61a and 61b are arranged alternately at regular angular intervals around the circumference. For example, the A-phase stator 61 has twelve pole teeth 61a and twelve pole teeth 61b. The angle between adjacent pole teeth 61a and 61b is 15 degrees. When a coil 61c of the A-phase stator 61 is energized, the pole teeth 61a and 61b exhibit opposite polarities.

[0036] The B-phase stator 62 includes a plurality of claw-type pole teeth 62a and 62b around its inner circumference. The tips of the pole teeth 62a point downwards, and the tips of the pole teeth 62b point upwards. The pole teeth 62a and 62b are arranged alternately at regular angular intervals around the circumference. For example, the B-phase stator 62 has twelve pole teeth 62a and twelve pole teeth 62b. The angle between adjacent pole teeth 62a and 62b is 15 degrees. When a coil 62c of the B-phase stator 62 is energized, the pole teeth 62a and 62b exhibit opposite polarities.

[0037] The A-phase stator 61 is arranged coaxially with the B-phase stator 62. The A-phase stator 61 is in contact with the B-phase stator 62. Viewed in the direction of axis L, the angle between the pole tooth 61a of the A-phase stator 61 and the pole tooth 62a of the B-phase stator 62, which are adjacent to each other, is 7.5 degrees.

[0038] The form element 63 fills the A-phase stator 61 and the B-phase stator 62. Together with the pole teeth 61a and 61b and the pole teeth 62a and 62b, the form element 63 creates an inner circumferential surface 60a of the stator. The diameter of the inner circumferential surface 60a of the stator is equal to that of the outer circumferential surface of the housing 20. The form element 63 includes a connection support section 64.

[0039] The terminal support section 64 extends laterally (in a direction perpendicular to the axis L) from the A-phase stator 61 and from the B-phase stator 62. The terminal support section 64 carries the terminals 65. The terminals 65 extend laterally from the tip end of the terminal support section 64. The terminals 65 are connected to the coil 61c of the A-phase stator 61 and the coil 62c of the B-phase stator 62.

[0040] In the electric valve 1, the respective central axes of the body element 11 (the valve opening 15 and the valve seat 16), the support element 13, the can 20, the magnetic rotor 31, the valve stem 34, the valve element 40 (the control section 45) and the stator 60 (the A-phase stator 61 and the B-phase stator 62) are aligned with the axis L.

[0041] The can 20 is arranged inside the stator 60. The magnetic rotor 31 is arranged inside the can 20. The magnetic rotor 31 and the stator 60 are components of a stepper motor 66.

[0042] The stepper motor 66 can perform full-step and micro-step operation. Fig. 6A and Fig. Figure 6B represents the positional relationships between the magnetic rotor 31 and the stator 60. Fig. Figure 6A shows a state in which the magnetic poles (the N and S poles) of the magnetic rotor 31 are radially oriented towards the pole teeth 61a and 61b of the A-phase stator 61. Fig. Figure 6B shows a state in which the magnetic poles of the magnet rotor 31 are radially oriented towards the pole teeth 62a and 62b of the B-phase stator 62. In the Fig. 6A and Fig. 6B is the magnetic pole marked with a black dot as a reference and the pole tooth is marked with a black dot as a reference.

[0043] Full-step operation involves rotating the magnetic rotor 31 in response to a single pulse input into the stepper motor 66 from a position (which is in Fig. 6A position), in which the magnetic poles are facing the pole teeth 61a and 61b, into a position (the one shown in Fig. 6B position), in which the magnetic poles face the pole teeth 62a and 62b, which are located next to the pole teeth 61a and 61b, or rotation of the magnetic rotor 31 in response to a single pulse input into the stepper motor 66 from the position shown in Fig. 6B shown position in the Fig. Position shown in 6A. In this embodiment, the rotation angle (one step angle) per pulse used in full-step operation is 7.5 degrees.

[0044] Microstepping involves rotating the magnetic rotor 31 in response to a single pulse input to the stepper motor 66 by an angle obtained by uniformly dividing the step angle used in full-step operation. Microstepping is achieved by fine-tuning the values ​​of the drive currents supplied to coil 61c of the A-phase stator 61 and coil 62c of the B-phase stator 62. For example, the step angle used in microstepping is 0.9375 degrees (dividing the angle into eight parts), 1.875 degrees (dividing the angle into four parts), or 1.5 degrees (dividing the angle into five parts). In this embodiment, microstepping also involves rotating the magnetic rotor 31 in response to a single pulse input at an angle (3.75 degrees) that is half the step angle used in full-step operation. This operation is also referred to as "half-step operation."

[0045] In this embodiment, when the stepper motor 66 performs a full step of 500 pulses, the magnetic rotor 31 rotates 3750 degrees and the valve element 40 moves from the valve closed position Pa to the fully open position Pz. In this description, "inputting pulses into the stepper motor 66" is synonymous with "supplying the stator 60 of the stepper motor 66 with drive currents corresponding to the pulses".

[0046] The housing 70 is made of synthetic resin. The housing 70 contains the stator 60 and the control unit 80. The housing 70 includes a circumferential wall section 71, an upper wall section 72, and a connector 73.

[0047] The circumferential wall section 71 has a circular cylindrical shape. The stator 60 is embedded in the circumferential wall section 71. The diameter of an inner circumferential surface 71a of the circumferential wall section 71 is equal to that of the stator's inner circumferential surface 60a. The inner circumferential surface 71a is flush with and continuous with the stator's inner circumferential surface 60a. The upper wall section 72 has a dome shape. The upper wall section 72 is connected to the upper end of the circumferential wall section 71. The connector 73 is located on the upper part of the housing 70. The inner circumferential surface 71a of the circumferential wall section 71, an inner surface 72a of the upper wall section 72, and the stator's inner circumferential surface 60a define an interior space 74 of the stator unit 50. The can 20 is located in the interior space 74.

[0048] The housing 70 has a printed circuit board compartment 75. The printed circuit board compartment 75 is located next to the interior space 74. A partition 76 is arranged between the interior space 74 and the printed circuit board compartment 75. The partition 76 separates the interior space 74 from the printed circuit board compartment 75. The housing 70 has an opening 70a that communicates with the printed circuit board compartment 75, and the opening 70a is closed by a cover element 77.

[0049] The controller 80 is located in the circuit board compartment 75 of the housing 70. The controller 80 includes a main circuit board 90, a sub-circuit board 100, a magnetic sensor 110, and a microcomputer 120.

[0050] The main circuit board 90 is a circuit board on which electronic components are mounted. The main circuit board 90 is housed in the circuit board compartment 75. The main circuit board 90 is arranged parallel to the up and down directions. The microcomputer 120 is mounted on the main circuit board 90. The terminals 65 of the stator 60 are connected to the main circuit board 90.

[0051] The sub-circuit board 100 is a circuit board on which electronic components are mounted. The sub-circuit board 100 is housed in the circuit board compartment 75. The sub-circuit board 100 is arranged perpendicular to the main circuit board 90. A first end 100a of the sub-circuit board 100 is located near the main circuit board 90. A second end 100b of the sub-circuit board 100 is located near the partition 76. The sub-circuit board 100 is connected to the main circuit board 90 via a circuit board connector.

[0052] The magnetic sensor 110 is, for example, a Hall-effect IC. The magnetic sensor 110 is located at the second end 100b of the sub-circuit board 100. The magnetic sensor 110 and the magnetic rotor 31 are arranged laterally, with the can 20 and the partition 76 located between them. The magnetic sensor 110 outputs a signal that corresponds to the direction of the magnetic field generated by the magnetic rotor 31.

[0053] For example, the Microcomputer 120 is a microcomputer for embedded devices in which a central processing unit, non-volatile memory, working memory, a communication module, a motor driver, etc., are integrated into a single package. The Microcomputer 120 controls the electric valve 1. The non-volatile memory, working memory, communication module, and motor driver can be separate electronic components connected externally to the Microcomputer 120.

[0054] Fig. Figure 7 represents a functional block diagram of the electric valve 1. As in Fig. As shown in Figure 7, the control unit 80 includes a memory unit 210, a communication unit 220, a processing unit 230, and a rotary control unit 240. The non-volatile memory serves as the memory unit 210. The central processing unit executes a program stored in the non-volatile memory and functions as the communication unit 220, the processing unit 230, and the rotary control unit 240. The working memory stores control variables used by the processing unit 230 and the rotary control unit 240. The communication module is connected to the control unit 400 of the air conditioning system via a cable (not shown) attached to terminal 73. The motor driver is connected to the stepper motor 66. Specifically, the motor driver is connected to the coil 61c of the A-phase stator 61 and the coil 62c of the B-phase stator 62. The motor driver supplies the drive currents corresponding to the pulses to coil 61c and coil 62c.

[0055] For example, storage unit 210 stores a table 310 which is in Fig. Figure 8 is shown. Table 310 includes a section information area 311, a pulse count information area 312, and a step angle information area 313.

[0056] Section information area 311 contains information points relating to the sections that lie between the valve closed position Pa and the fully open position Pz of the valve element 40. Section information area 311 contains "a first section" and "a second section" as information points relating to the sections.

[0057] In pulse count information area 312, information points (pulse count information) are set with respect to the pulse counts, which are assigned in ascending order to intervals between the valve closed position Pa and the fully open position Pz of the valve element 40. Pulse counts "1" to "1000" are set as the pulse count information points in pulse count information area 312. Pulse counts "1" to "600" are assigned to the "first section" of section information area 311, and pulse counts "601" to "1000" are assigned to the "second section" of section information area 311.

[0058] Fig. Figure 9 represents a relationship between the pulse counts assigned to the intervals between the valve closed position Pa and the fully open position Pz and the positions of the valve element 40. In the motion section, the positions "0" to "1000" of the valve element 40 are set in ascending order from the valve closed position Pa to the fully open position Pz. The pulse counts "1" to "1000" are assigned to the intervals between the positions "0" to "1000". Pulse count "1" is assigned to the interval between positions "0" and "1", pulse count "2" is assigned to the interval between positions "1" and "2", and so on.For example, if the valve element 40 is at position "1", the information point with respect to pulse number "1" is used to move the valve element 40 to position "0", or the information point with respect to pulse number "2" is used to move the valve element 40 to position "2". In this embodiment, position "0" serves as the valve closing position Pa, position "600" serves as a first position, and position "1000" serves as a second position and as the fully open position Pz. The second position is further from the valve closing position Pa than the first position.

[0059] In step angle information area 313, information points (step angle information) are set with respect to the step angles, each corresponding to one of the pulse counts set in pulse count information area 312. In step angle information area 313, the numbers of the parts into which the step angle used in full-step operation is subdivided are set as step angle information points. In step angle information area 313, "8" is set corresponding to pulse counts "1" to "600," and "1" is set corresponding to pulse counts "601" to "1000." In other words, 7.5 degrees / 8 = 0.9375 degrees is set as the step angle used in the "first section," and 7.5 degrees / 1 = 7.5 degrees is set as the step angle used in the "second section."The step angle of stepper motor 66 used in the first section differs from the step angle used in the second section. The step angle of stepper motor 66 used in the first section is smaller than the step angle used in the second section. Numerical values ​​can be set as step angle information points, each specifying a step angle.

[0060] Although the memory unit 210 stores the pulse count information and the step angle information in a tabular format, the memory unit 210 can store them in a different format, such as a mathematical expression.

[0061] Since the stepper motor 66 (the magnetic rotor 31) is rotated based on Table 310, the electric valve 1 operates as an electric valve with the values ​​specified in Table 310. Fig. The flow rate characteristic curves shown in the 10 curves are shown. Fig. In the flow rate characteristic shown in Figure 10, the step angles in the first and second sections are constant. In addition to this configuration, another configuration can be used, for example, in which the step angle set in the first section of Table 310 increases with increasing pulse count. This allows the electric valve 1 to be used as an electric valve with the parameters shown in Figure 10. Fig. to work with the flow rate characteristic curves shown in 11. In the in Fig. In the flow rate characteristic curves shown in Figure 11, the rate of change of the flow rate per pulse gradually increases as the number of pulses in the first section increases. For example, a third section may be provided after the second section in Table 310. The step angle used in the third section is set to be larger than that used in the second section and is constant. This allows the electric valve 1 to function as an electric valve with the characteristics shown in Figure 11. Fig. The flow rate characteristic curves shown in the 12 diagrams are used for this purpose. Fig. In section 12, position “0” of valve element 40 serves as the valve closing position Pa, position “800” of valve element 40 serves as a first position, position “1200” of valve element 40 serves as a second position, and position “1500” of valve element 40 serves as a third position and as the fully open position Pz. The third position is further from the valve closing position Pa than the second position. A desired flow rate characteristic can be obtained in the electric valve 1 by appropriately adjusting the step angles in Table 310.

[0062] The communication unit 220 communicates with the control unit 400 via the communication module. The communication unit 220 receives various commands from the control unit 400 and transmits them to the processing unit 230. The communication unit 220 receives various states of the electric valve 1 from the processing unit 230 and the rotary control unit 240 and transmits them to the control unit 400. The communication unit 220 receives a command to move the valve element from the control unit 400. The command to move the valve element contains information regarding a target position Pt of the valve element 40. This information specifies a target valve opening degree. The information can specify a relative movement distance (the number of pulses or the like) from a current position Pc of the valve element 40. The processing unit 230 receives the target position Pt of the valve element 40 based on this information.

[0063] The current position Pc of the valve element 40 is stored in the working memory when the electric valve 1 is in operation, and is stored in the storage unit 210 when the electric valve 1 is switched off.

[0064] For electric valve 1, the valve opening degrees 0% to 100% set by control unit 400 correspond to positions "0" to "1000" of valve element 40. For example, if the valve opening degree included in the command to move the valve element is 0%, the target position Pt is position "0". If the valve opening degree included in the command to move the valve element is 25%, the target position Pt is position "250". If the valve opening degree included in the command to move the valve element is 50%, the target position Pt is position "500". If the valve opening degree included in the command to move the valve element is 75%, the target position Pt is position "750".If the valve opening degree specified in the command to move the valve element is 100%, the target position Pt is position "1000". If the number indicating the current position Pc of the valve element 40 is less than the number indicating the target position Pt of the valve element 40, the direction of rotation of the stepper motor 66 is a direction (a valve opening direction) in which the valve element 40 moves away from the valve seat 16. If the number indicating the current position Pc of the valve element 40 is greater than the number indicating the target position Pt of the valve element 40, the direction of rotation of the stepper motor 66 is a direction (a valve closing direction) in which the valve element 40 moves towards the valve seat 16.

[0065] The processing unit 230 performs various arithmetic operations. When the communication unit 220 receives the command to move the valve element, the processing unit 230 receives the position of the valve element 40, corresponding to the valve opening degree specified in the command to move the valve element, as the target position Pt. For example, if the valve opening degree is 10 [%], the processing unit 230 receives the position "100" as the target position Pt. If the valve opening degree is 50 [%], the processing unit 230 receives the position "500" as the target position Pt. If the valve opening degree is 90 [%], the processing unit 230 receives the position "900" as the target position Pt.

[0066] The arithmetic unit 230 then receives the pulse count between the current position Pc (a starting point) of the valve element 40 and the target position Pt (a destination point) of the valve element 40. For example, if the current position Pc is position "0" and the target position Pt is position "150", the arithmetic unit 230 receives pulse counts "1" to "150". If the current position Pc is position "150" and the target position Pt is position "750", the arithmetic unit 230 receives pulse counts "151" to "750". If the current position Pc is position "750" and the target position Pt is position "300", the arithmetic unit 230 receives pulse counts "750" to "301".

[0067] In addition, the computing unit 230 receives the rotation angle and the state (rotating or stopped) of the magnetic rotor 31 based on the signal output by the magnetic sensor 110.

[0068] The rotary control unit 240 receives the step angle information points, each corresponding to one of the pulse numbers, sequentially from Table 310 in the order of the pulse numbers assigned to the intervals between the current position Pc of the valve element 40 and the target position Pt of the valve element 40. The rotary control unit 240 then calculates the step angle using the step angle information points and inputs the pulses, step angles, and direction of rotation into the motor driver to rotate the stepper motor 66.

[0069] The rotary control unit 240 determines whether the command to move the valve element was successful or failed. Specifically, the rotary control unit 240 compares the rotation angle (a calculated rotation angle) of the magnetic rotor 31, obtained by summing the step angles, each corresponding to one of the pulse numbers assigned to the intervals between the current position Pc and the target position Pt, with the rotation angle (a measured rotation angle) of the magnetic rotor 31, obtained by the computing unit 230 based on the signal from the magnetic sensor 110. If the calculated rotation angle matches the measured rotation angle, the rotary control unit 240 transmits information indicating that the command to move the valve element was successful, as a command result, to the control unit 400 via the communication unit 220.If the calculated rotation angle does not match the measured rotation angle, the rotary control unit 240 transmits information indicating that the command to move the valve element has failed as a command result via the communication unit 220 to the control unit 400.

[0070] The following describes an example of normal operation of the electric valve 1.

[0071] The controller 80 of the electric valve 1 enters a start state when the controller 80 is switched on. In the start state, the controller 80 copies the current position Pc from the memory unit 210 into the working memory and then switches to a normal operating mode. In the normal operating mode, the controller 80 waits for a command transmitted by the control unit 400. The control unit 400 assumes that the electric valve 1 has the in Fig. The flow rate characteristic curves shown in Figure 10 are shown. For example, the current position Pc of the valve element 40 is set to the valve closing position Pa (position “0”) immediately after the transition of the electric valve 1 to normal operating mode.

[0072] Upon receiving a command from control unit 400 to move the valve element, specifying a valve opening of 90%, control unit 80 receives, for example, position "900" as the target position Pt. Control unit 80 receives pulse numbers "1" to "900", which correspond to the intervals between the current position Pc and the target position Pt.

[0073] The controller 80 calculates the step angles corresponding to pulse numbers "1" to "900" based on Table 310. Since the number indicating the current position Pc (position "0") is smaller than the number indicating the target position Pt (position "900"), the controller 80 sets the direction of rotation to the valve opening direction. The controller 80 inputs the pulses, step angles, and direction of rotation into the motor driver to rotate the stepper motor 66 (the magnetic rotor 31). The valve stem 34 rotates together with the magnetic rotor 31 in the valve opening direction. The screw feed operation between the internal thread 13c of the support element 13 and the external thread 34c of the valve stem 34 moves the valve stem 34 upward. The valve element 40 moves upward together with the valve stem 34, and the valve element 40 moves away from the valve seat 16.The controller 80 adds the step angles corresponding to the pulse counts "1" to "900" to obtain the rotation angle (the calculated rotation angle) of the magnetic rotor 31. The controller 80 obtains the rotation angle (the measured rotation angle) of the magnetic rotor 31 based on the signal from the magnetic sensor 110.

[0074] When the rotation of the stepper motor 66, with step angles corresponding to pulse numbers "1" to "900", is complete, the controller 80 stores position "900" as the current position Pc in its memory. The controller 80 determines whether the command to move the valve element was successful or failed. Specifically, the controller 80 compares the calculated rotation angle with the measured rotation angle. If the calculated rotation angle matches the measured rotation angle, the controller 80 transmits the information indicating that the command to move the valve element was successful as the command result to the control unit 400. If the calculated rotation angle does not match the measured rotation angle, the controller 80 transmits the information indicating that the command to move the valve element failed as the command result to the control unit 400.Then the controller 80 waits for the following command, which is transmitted by the control unit 400.

[0075] Next, for example, after receiving the command to move the valve element, which specifies a valve opening of 50%, the controller 80 receives the position "500" as the target position Pt from the control unit 400. The controller 80 receives the pulse numbers "900" to "501", which are assigned to the intervals between the current position Pc and the target position Pt.

[0076] The controller 80 calculates the step angles corresponding to pulse counts "900" to "501" based on Table 310. Since the number indicating the current position Pc (position "900") is greater than the number indicating the target position Pt (position "500"), the controller 80 sets the direction of rotation to the valve closing direction. The controller 80 inputs the pulses, step angles, and direction of rotation into the motor driver to rotate the stepper motor 66 (the magnetic rotor 31). The valve stem 34 rotates together with the magnetic rotor 31 in the valve closing direction. The screw feed operation between the internal thread 13c of the support element 13 and the external thread 34c of the valve stem 34 moves the valve stem 34 downwards. The valve element 40 moves downwards together with the valve stem 34, and the valve element 40 moves towards the valve seat 16.The controller 80 adds up the step angles corresponding to pulse numbers "900" to "501" to obtain the rotation angle (the calculated rotation angle) of the magnetic rotor 31. The controller 80 obtains the rotation angle (the measured rotation angle) of the magnetic rotor 31 based on the signal from the magnetic sensor 110.

[0077] When the rotation of the stepper motor 66, with step angles corresponding to pulse numbers "900" to "501", is complete, the controller 80 stores position "501" as the current position Pc in its working memory. The controller 80 determines whether the command to move the valve element was successful or failed and transmits its result to the control unit 400. The controller 80 then waits for the next command transmitted by the control unit 400. Afterward, the controller 80 executes operations according to the received commands. Upon receiving a shutdown command from the control unit 400, the controller 80 copies the current position Pc from its working memory to the memory unit 210 and prepares to shut down.

[0078] The following is an example of a procedure for obtaining the valve element position of the electric valve 1. Before the electric valve 1 is shipped from the factory, the table 310 and the current position Pc of the valve element 40 are stored in the memory unit 210.

[0079] Fig. Figure 13 presents an example of a system for adjusting the electric valve before shipment from the factory. The controller 80 of the electric valve 1 is connected to an adjustment device 500 via a cable attached to the connector 73. For example, a desktop computer serves as the adjustment device 500. The adjustment device 500 can control the stepper motor 66 via the controller 80. The adjustment device 500 can store various information in the memory unit 210 of the controller 80. The adjustment device 500 can rotate the stepper motor 66 at a constant step angle in the motion section between the valve closed position Pa and the fully open position Pz. In this embodiment, the adjustment device 500 controls the stepper motor 66 to perform full-step operation (the step angle: 7.5 degrees).The valve opening degrees 0 [%] to 100 [%] set by the adjusting device 500 correspond to positions “0” to “500” of the valve element 40. When 500 pulses are input to the stepper motor 66, the valve element 40 moves from the valve closed position Pa (position “0”) to the fully open position Pz (position “500”). A memory device of the adjusting device 500 stores a flow rate F0, which is determined by design, of fluid flowing through the valve opening 15 when the valve element 40 is in the valve closed position Pa.

[0080] A fluid supply device 510 is connected to the flow channel 17 of the electric valve 1, and a flow rate measuring device 520 is connected to the flow channel 18 of the electric valve 1. The fluid supply device 510 can supply fluid at a constant flow rate. The flow rate measuring device 520 measures the flow rate of fluid flowing out of the flow channel 18. The fluid supply device 510 and the flow rate measuring device 520 are controlled by the adjusting device 500.

[0081] The adjusting device 500 controls the fluid supply device 510 to begin supplying fluid to the electric valve 1.

[0082] The adjusting device 500 considers the current position of the valve element 40 of the electric valve 1 as position P1 and receives a flow rate measured by the flow rate measuring device 520 as a fluid flow rate F1 at position P1. The adjusting device 500 stores a combination C1 of position P1 and flow rate F1 in the storage device. The adjusting device 500 can estimate position P1 based on the flow rate F1.

[0083] The adjusting device 500 inputs pulses into the stepper motor 66 to rotate it and move the valve element 40 to a position P2 that differs from position P1. The adjusting device 500 receives a flow rate measured by the flow rate measuring device 520 as the flow rate F2 of fluid at position P2. The adjusting device 500 stores a combination C2 of position P2 and flow rate F2 in the storage device.

[0084] The adjusting device 500 calculates a change (a slope A) in the flow rate per pulse based on the combinations C1 and C2. In particular, the slope A is calculated using the following expression (1). P1 is the number indicating position P1, P2 is the number indicating position P2, F1 is the flow rate of fluid when the valve element 40 is at position P1, and F2 is the flow rate of fluid when the valve element 40 is at position P2. A=|F2−F1| / |P2−P1|

[0085] The adjusting device can calculate the slope A based on three or more of the combinations (C1, C2, ... , Cn).

[0086] The adjusting device 500 sets the flow rate F0 as an axis intercept B and determines a linear function expression that represents a relationship between the position of the valve element 40 and the flow rate of fluid flowing through the valve opening 15. Where X represents the position and Y represents the flow rate, the linear function expression is expressed by the following expression (2). Y=AX+B

[0087] The adjusting device 500 replaces Y in expression (2) with the flow rate measured by the flow rate measuring device 520 to calculate position X and sets position X as the current position Pc of the valve element 40.

[0088] The adjusting device 500 rotates the stepper motor 66 to move the valve element 40 from the current position Pc to the valve closing position Pa.

[0089] The setting device 500 then saves the table 310 in the memory unit 210 and also saves the position “0” as the current position Pc in the memory unit 210.

[0090] For example, if combination C1 contains position “100” and flow rate “40%”, combination C2 contains position “200” and flow rate “60%”, and flow rate F0 is flow rate “0%”, adjusting device 500 receives the following expression (2A) where slope A is 0.2 and intercept B is 0. Y=0.2x

[0091] If the flow rate at the current position of valve element 40 of electric valve 1 is, for example, "60%", the adjusting device 500 obtains position "300" by using expression (2A) as the current position Pc of valve element 40. The adjusting device 500 inputs 300 pulses to the stepper motor 66 to rotate it and move valve element 40 from position "300" to position "0". The adjusting device 500 stores table 310 in memory unit 210 and also stores position "0" in memory unit 210 as the current position Pc.

[0092] The electric valve 1 comprises the valve body 10, which has the valve opening 15 and the valve seat 16, which surrounds the valve opening 15; the valve element 40, which faces the valve opening 15; the stepper motor 66 for moving the valve element 40; and the controller 80, which controls the stepper motor 66. The valve element 40 includes the control section 45, which has a conical shape. The stepper motor 66 rotates to move the valve element 40 into the movement section between the valve closed position Pa and the fully open position Pz. When the valve element 40 is in the valve closed position Pa, the control surface 46 of the control section 45 is in contact with the valve seat 16. As the valve element 40 moves from the valve closed position Pa and is in the movement section, the throttle passage between the valve seat 16 and the control surface 46 is formed.The motion section comprises the first section between the valve closing position Pa and the first position (position "600") and the second section between the first position and the second position (the fully open position Pz). The second position is further from the valve closing position Pa than the first position. The controller 80 sets the step angle for the stepper motor 66 when the valve element 40 is in the first section and sets the step angle when the valve element 40 is in the second section, with the step angles being different from each other.

[0093] According to this configuration, the control surface 46 of the control section 45, which has the only conical shape, is in contact with the valve seat 16 when the valve element 40 is in the valve closing position Pa. When the valve element 40 moves from the valve closing position Pa and is in the movement section, the throttle passage between the valve seat 16 and the control surface 46 is formed. Therefore, variation in the throttle passage area can be prevented. Additionally, the controller 80 sets the step angle for the stepper motor 66 when the valve element 40 is in the first section and sets a different step angle when the valve element 40 is in the second section. Therefore, a desired flow rate characteristic can be obtained by appropriately adjusting the step angles in the first and second sections.

[0094] The step angle when valve element 40 is in the first section is smaller than the step angle when valve element 40 is in the second section. This configuration allows for fine control of the flow rate when the electric valve 1 is in a microflow state, where the area of ​​the throttle passage is relatively small.

[0095] The step angle when the valve element 40 is in the first section can be larger than the step angle when the valve element 40 is in the second section.

[0096] The stepper motor 66 includes the magnetic rotor 31, the A-phase stator 61, and the B-phase stator 62. When the valve element 40 is in the first section, the controller 80 controls the stepper motor 66 to perform microstepping. When the valve element 40 is in the second section, the controller 80 controls the stepper motor 66 to perform full-step operation. With this configuration, the step angle can be smaller when the valve element 40 is in the first section than when it is in the second section, through relatively simple control.

[0097] Alternatively, if the valve element 40 is located in the first section, the controller 80 can set the excitation mode of the stepper motor 66 to 1-2 phase excitation, and if the valve element 40 is located in the second section, the controller 80 can set the excitation mode of the stepper motor 66 to 2 phase excitation.

[0098] The procedure for obtaining the valve element position of the electric valve 1 includes (1) the step of obtaining two or more combinations of the position of the valve element 40 and the flow rate of fluid flowing through the valve opening 15 when the valve element 40 is at position , (2) the step of determining the linear function expression that represents the relationship between the position and the flow rate based on the design flow rate F0 when the valve element 40 is at the valve closing position Pa, and the combinations thereof, and (3) the step of obtaining the current position Pc of the valve element 40 by using the linear function expression. With this configuration, the current position Pc and the valve closing position Pa of the valve element 40 can be obtained based on the measured flow rate.Therefore, the electric valve 1 can have a configuration in which a stopper mechanism that physically restricts the rotation of the magnetic rotor 31 at the valve closing position Pa is omitted. The method for maintaining the valve element position can be applied to an electric valve in which the control surface 46 is not in contact with the valve seat 16 when the valve element 40 is in the valve closing position Pa.

[0099] When the valve element 40 is in the valve closing position Pa, the control surface 46 in the electric valve 1 is in contact with the inner circumferential edge 16a of the valve seat 16, thus preventing the valve element 40 from moving downwards. In other words, the valve closing position Pa coincides with a position in which the downward movement of the valve element 40 is restricted. Before the electric valve 1 is shipped from the factory, the linear function expression determined in step (2) above can be stored in the memory unit 210 of the controller 80. The electric valve 1 is installed in the cooling circuit system.When the controller 80 receives the command to move the valve element (for example, including a target flow rate) from the control unit 400, the controller 80 can control the stepper motor 66 to move the valve element 40 using the current flow rate, the target flow rate, and the linear function expression. The flow rate of the fluid flowing through the electric valve 1 corresponds to the position of the valve element 40. That is, the flow rates 0% to 100% of the electric valve 1 correspond to positions "0" to "500".

[0100] Since the valve stem 34 of the electric valve 1 is attached to the magnetic rotor 31, the rotation of the magnetic rotor 31 in the valve closing direction is restricted simultaneously with the downward movement of the valve element 40. In addition to this configuration, a configuration can be used in which the rotation of a magnetic rotor 31 in the valve closing direction is restricted by a stopper mechanism 41 after the downward movement of a valve element 40 has been restricted, such as a [missing information - likely a specific type of mechanism]. Fig. 14 Electric valve 1A shown.

[0101] As in Fig.As shown in Figure 14, the electric valve 1A comprises a valve body 10, a can 20, an actuating mechanism 30A, the valve element 40, and a control 80. In the description of the electric valve 1A, elements with the same (including substantially the same) configuration as those of the electric valve 1 are designated with the same reference numerals as those of the electric valve 1, and detailed descriptions of these elements are omitted.

[0102] The drive mechanism 30A moves the valve element 40 in an up and down direction. The drive mechanism 30A includes the magnetic rotor 31, a valve stem holder 32, a guide bushing 33, a valve stem 34A, a permanent magnet 38, the stopper mechanism 41, and a stator unit 50.

[0103] The valve stem holder 32 has a circular cylindrical shape. It is open at the lower end and closed at the upper end. A support ring 35 is attached to the upper end of the valve stem holder 32. The support ring 35 couples the magnetic rotor 31 to the valve stem holder 32. The valve stem holder 32 has an internal thread 32c. The internal thread 32c is located on the inner circumferential surface of the valve stem holder 32.

[0104] The guide bushing 33 has a circular cylindrical shape. The outer diameter of the upper part of the guide bushing 33 is smaller than that of the lower part of the guide bushing 33. The lower part of the guide bushing 33 is pressed into a fitting bore 13a provided in a support element 13. The guide bushing 33 has an external thread 33c. The external thread 33c is located on the outer circumferential surface of the upper part of the guide bushing 33. The external thread 33c is screwed into the internal thread 32c of the valve stem holder 32. The guide bushing 33 is connected to the support element 13. In the electric valve 1A, the support element 13 does not have an internal thread 13c.

[0105] The valve stem 34A comprises a large-diameter section 34a and a small-diameter section 34b. Both the large-diameter section 34a and the small-diameter section 34b have a circular column shape. The outer diameter of the large-diameter section 34a is slightly smaller than the inner diameter of the guide bushing 33. The outer diameter of the small-diameter section 34b is smaller than that of the large-diameter section 34a. The small-diameter section 34b is coaxially connected to the upper end of the large-diameter section 34a. The small-diameter section 34b extends through the valve stem holder 32. A pressure nut 36 is attached to the small-diameter section 34b as a retainer. The valve stem 34A is arranged within the guide bushing 33 and the support element 13.The guide bushing 33 movably supports the valve stem 34A in the up and down directions. The lower end of the valve stem 34A is located in a valve chamber 14. The valve stem 34A has a stepped section. The stepped section is located at the junction of the large-diameter section 34a and the small-diameter section 34b. The stepped section is an upwardly facing annular plane. A valve closing spring 37 is located between the valve stem holder 32 and the stepped section. The valve closing spring 37 is a compression coil spring. The valve closing spring 37 presses the valve stem 34A downwards.

[0106] The permanent magnet 38 is located above the magnetic rotor 31 inside the housing 20. The permanent magnet 38 has a circular, ring-shaped, flat, plate-like form. The permanent magnet 38 has a north pole (N) and a south pole (S). The permanent magnet 38 comprises two parts divided by its diameter, with the north pole located in one of the two parts and the south pole in the other. The permanent magnet 38 is attached to the support ring 35 by a fastening element 39. The permanent magnet 38 rotates together with the magnetic rotor 31.

[0107] In the electric valve 1A, a magnetic sensor 110 serves as a rotation angle sensor. The magnetic sensor 110 faces the permanent magnet 38 laterally, with the can 20 and a partition 76 located between them. The magnetic sensor 110 outputs a signal corresponding to the direction of the magnetic field generated by the permanent magnet 38 (i.e., a rotation angle of the magnetic rotor 31, which rotates together with the permanent magnet 38).

[0108] The stopper mechanism 41 comprises a movable stopper 42 and a fixed stopper 43. The movable stopper 42 is attached to the valve stem holder 32. The movable stopper 42 rotates together with the valve stem holder 32. The fixed stopper 43 is attached to the lower part of the guide bushing 33. When the movable stopper 42 comes into contact with the fixed stopper 43, the rotation of the valve stem holder 32 (i.e., the magnetic rotor 31) in the valve closing direction is restricted.

[0109] The internal thread 32c of the valve stem holder 32 and the external thread 33c of the guide bushing 33 form a screw feed mechanism. When the magnetic rotor 31 rotates in a valve opening direction, a screw feed action between the internal thread 32c and the external thread 33c moves the valve stem holder 32 upward, and the valve stem holder 32 pushes the pressure nut 36 upward. This causes the valve stem 34A and the valve element 40 to move upward. When the magnetic rotor 31 rotates in the valve closing direction, the screw feed action between the internal thread 33c and the external thread 34c moves the valve stem holder 32 downward, and the valve stem holder 32 pushes the valve stem 34A downward via the valve closing spring 37. This causes the valve stem 34A and the valve element 40 to move downward.When the valve element 40 moves downwards and a control surface 46 comes into contact with an inner circumferential edge 16a of a valve seat 16, the downward movement of the valve element 40 is restricted. As the magnetic rotor 31 continues to rotate in the valve closing direction, the valve closing spring 37 is compressed, the movable stopper 42 comes into contact with the fixed stopper, and the rotation of the magnetic rotor 31 in the valve closing direction is restricted.

[0110] Before the electric valve 1A is shipped from the factory, a storage unit 210 of the control 80 can store the following: [i] the linear function expression determined in step (2) above; [ii] a valve closing position Pa, calculated by using the linear function expression; and [iii] a virtual position (a reference position Px) of the valve element 40 when the movable stopper 42 comes into contact with the fixed stopper 43.

[0111] In reality, the downward movement of the valve element 40 is restricted when it comes into contact with the valve seat 16. The "virtual position of the valve element 40" is the position the valve element 40 would reach if its movement were unrestricted and it had moved downwards. If, for electric valve 1A, the number indicating the valve closing position Pa is "0", the number indicating the reference position Px is a negative value, and the flow rate when the valve element 40 is at the reference position Px is also a negative value. The reference position Px and the flow rate when the valve element 40 is at the reference position Px satisfy the linear function expression. For example, the flow rate is -20%. Electric valve 1A is installed in the cooling circuit system.When the controller 80 receives the command to move the valve element (for example, including a target flow rate) from the control unit 400, the controller 80 can control the stepper motor 66 using the current flow rate, the target flow rate, and the linear function expression. The flow rate of fluid passing through the electric valve 1A corresponds to the position of the valve element 40. That is, flow rates from 0% to 100% of the electric valve 1A correspond to positions "0" to "500". Flow rates from -20% to 0% of the electric valve 1A correspond to positions "-100" to "0".

[0112] For example, if the current position Pc of electric valve 1A is position "50" (flow rate 10%) and controller 80 receives a command to move the valve element corresponding to a flow rate of 30%, controller 80 calculates the position (target position Pt, position "150") of valve element 40 corresponding to a flow rate of 30% using a linear function expression. Controller 80 then inputs the difference in pulses between the number (150), which indicates the target position Pt, and the number (50), which indicates the current position Pc, into stepper motor 66.

[0113] For example, if the current position Pc of electric valve 1A is the reference position Px (position "-100", flow rate -20%), and the controller 80 receives a command to move the valve element corresponding to a flow rate of 30%, the controller 80 calculates the position (target position Pt, position "150") of the valve element 40 corresponding to the 30% flow rate using a linear function expression. The controller 80 then inputs the difference in pulses between the number (150), which indicates the target position Pt, and the number (-100), which indicates the current position Pc, into the stepper motor 66.

[0114] In the electric valve 1A, the number of pulses (a valve opening pulse count), corresponding to the distance from the reference position Px to the valve closing position Pa, can be pre-stored in the memory unit 210. The electric valve 1A can calculate the position of the valve element 40 in a movement section between the valve closing position Pa and a fully open position Pz by using the linear function expression, and in a section between the reference position Px and the valve closing position Pa by using the valve opening pulse count.

[0115] Although the electric valve 1 is a directly driven electric valve that includes the drive mechanism 30 which uses the rotation of the magnetic rotor 31 without speed reduction, the present invention is also applicable to an electric valve that includes a drive mechanism which has a mechanism for reducing the rotational speed of a magnetic rotor.

[0116] In this description, terms that specify shapes, such as "circular cylindrical" and "circular column shape," are also used for elements and sections of elements that essentially have the shapes specified by the terms. For example, "circular cylindrical element" includes a circular cylindrical element and an essentially circular cylindrical element.

[0117] The embodiments of the present invention are described above. However, the present invention is not limited to these embodiments. Embodiments obtained by a person skilled in the art by appropriately adding, removing, or modifying components according to the embodiments described above, and an embodiment obtained by appropriately combining features of the embodiments, fall within the scope of protection of the present invention without departing from the spirit of the present invention. Reference symbol list

[0118] 1, 1A ... electric valve, 10 ... valve body, 11 ... body element, 11a ... first mounting hole, 11b ... top surface, 12 ... flow channel block, 12a ... second mounting hole, 12b ... top surface, 13 ... support element, 13a ... fitting hole, 13c ... internal thread, 14 ... valve chamber, 15 ... valve opening, 15a ... top end, 16 ... valve seat, 16a ... inner circumferential edge, 17 ... flow channel, 18 ... flow channel, 20 ... can, 25 ... connecting element, 30, 30A ... actuation mechanism, 31 ... magnetic rotor, 32 ... valve stem holder, 32c ... internal thread, 33 ... guide bushing, 33c ... external thread, 34, 34A ... valve stem, 34a ... large diameter section, 34b ... section with small diameter, 34c ... external thread, 35 ... support ring, 36 ... pressure nut, 37 ... valve closing spring, 38 ... permanent magnet, 39 ... fastening element, 40 ... valve element, 41 ... stopper mechanism, 42 ... movable stopper, 43 ... fixed stopper, 45 ...Control section, 45a ... lower end, 46 ... control surface, 50 ... stator unit, 60 ... stator, 60a ... stator inner circumferential surface, 61 ... A-phase stator, 61a ... pole tooth, 61b ... pole tooth, 61c ... coil, 62 ... B-phase stator, 62a ... pole tooth, 62b ... pole tooth, 62c ... coil, 63 ... molded element, 64 ... connection support section, 65 ... connection, 66 ... stepper motor, 70 ... housing, 70a ... opening, 71 ... circumferential wall section, 71a ... inner circumferential surface, 72 ... upper wall section, 72a ... inner surface, 73 ... connector, 74 ... interior, 75 ... circuit board space, 76 ... partition, 77 ... cover element, 80 ... control, 90 ... main circuit board, 100 ... sub-circuit board, 100a ... first end, 100b ... second end, 110 ... magnetic sensor, 120 ... microcomputer, 210 ... storage unit, 220 ... communication unit, 230 ... computing unit, 240 ... rotary control unit, 310 ... table, 311 ... section information area, 312 ... pulse count information area, 313 ...Step angle information area, 400 ... Control unit, 500 ... Adjustment device, 510 ... Fluid supply device, 520 ... Flow rate measuring device, L ... Axis, Pa ... Valve closing position, Pz ... Fully open position. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2018-179133

[0003]

Claims

[1] An electric valve comprising: a valve body having a valve opening and a valve seat surrounding the valve opening; a valve element facing the valve opening; a stepping motor for moving the valve element; and a controller controlling the stepping motor, wherein the valve element includes a control portion having a single conical shape, wherein the stepper motor rotates to move the valve element in a movement section between a valve closing position and a fully open position, wherein, when the valve element is at the valve closing position, an outer peripheral surface of the control portion is in contact with the valve seat, wherein, when the valve element moves from the valve closing position and is in the moving section, a throttle passage is formed between the valve seat and the outer peripheral surface, wherein the movement section includes a first section between the valve closing position and a first position and a second section between the first position and a second position which is farther from the valve closing position than the first position, and wherein the controller sets one step angle for the stepper motor when the valve element is in the first section and sets another step angle when the valve element is in the second section, the step angles being different from each other. [2] The electric valve of claim 1, wherein the step angle when the valve element is in the first section is smaller than the step angle when the valve element is in the second section. [3] Electric valve according to claim 2, wherein the stepper motor includes a magnetic rotor, an A-phase stator and a B-phase stator, wherein, when the valve element is in the first section, the controller controls the stepper motor to perform a microstep operation, and wherein, when the valve element is in the second section, the controller controls the stepper motor to perform full step operation. [4] Electric valve according to claim 2, wherein the stepper motor includes a magnetic rotor, an A-phase stator and a B-phase stator, wherein, when the valve element is in the first section, the controller sets an excitation mode of the stepper motor to 1-2 phase excitation, and When the valve element is in the second section, the controller sets the excitation mode of the stepper motor to 2-phase excitation. [5] A method for obtaining a valve element position of an electric valve, which includes a valve body having a valve opening and a valve seat enclosing the valve opening, a valve element facing the valve opening, a stepping motor for moving the valve element, and a controller that controls the stepping motor, wherein the valve element includes a control portion having a single conical shape, the stepping motor rotating to move the valve element in a moving section between a valve closing position and a fully open position, wherein a throttle passage is formed between the valve seat and an outer peripheral surface of the control portion when the valve element moves from the valve closing position and is in the moving section, the method comprising: a step of obtaining two or more combinations of a position of the valve element and a flow rate of fluid flowing through the valve opening when the valve element is at the position; a step of determining a linear function expression representing a relationship between the position and the flow rate based on a design flow rate when the valve element is at the valve closing position and the combinations; and a step of obtaining a current position of the valve element by using the linear function expression.

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