JP2022093843A - Motor-operated valve - Google Patents

Abstract

To increase versatility of design of a sensor magnet being a detection object, in a motor-operated valve with a magnetic sensor.SOLUTION: A motor-operated valve 1 comprises: an operation rod 32 axially supporting a valve element 34; a rotor 60 operating the operation rod 32; a magnetic sensor 119 detecting the displacement amount of the rotor 60; and a screw feeding mechanism 109 converting the rotary motion of the rotor 60 into the axial motion of the operation rod 32. The rotor 60 includes a rotor core 102, a rotor magnet 104 provided in the outer periphery of the rotor core 102, and a sensor magnet 106 provided at the axial end of the rotor core 102. The magnetic sensor 119 is axially opposed to the sensor magnet 106 and detects the magnetic flux of the sensor magnet 106 to thereby detect the displacement amount of the rotor 60. A hole portion 107 formed along the axis is provided in the sensor magnet 106.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electric valve including a magnetic sensor for detecting a valve opening degree.

An automobile air conditioner is generally configured by arranging a compressor, a condenser, an inflator, an evaporator, and the like in a refrigeration cycle. The refrigeration cycle is provided with various control valves for controlling the flow of the refrigerant, such as an expansion valve as an expansion device. With the spread of electric vehicles and the like in recent years, electric valves equipped with a motor as a drive unit are being widely adopted.

As such an electric valve, a valve provided with a magnetic sensor for detecting the valve opening degree is known (for example, Patent Document 1). A valve body is provided at one end of an operating rod that rotates with the rotor, and a magnet (sensor magnet) is provided at the other end. A magnetic sensor is provided so as to face the sensor magnet in the axial direction. The rotary motion of the rotor is converted into the axial motion of the valve body by the screw feed mechanism. By capturing the change in magnetic flux with the rotation of the rotor with a magnetic sensor, the rotation angle of the sensor magnet and thus the axial position of the valve body can be detected, and the valve opening can be calculated.

Japanese Unexamined Patent Publication No. 2018-135908

In such an electric valve, a hole is provided in the center of the sensor magnet, and the other end of the operating rod is coaxially inserted and fixed in the hole. Therefore, it is necessary to match the inner diameter of the hole of the sensor magnet with the outer diameter of the operating rod. Therefore, there is little freedom in adjusting the magnetic characteristics of the sensor magnet according to the size of the hole. It should be noted that such a problem may occur not only in the refrigeration cycle but also in the motorized valve used for various purposes.

One of the objects of the present invention is to increase the degree of freedom in designing a sensor magnet to be detected in an electric valve provided with a magnetic sensor.

One aspect of the present invention is a motorized valve. This electric valve has an operating rod that supports the valve body in the axial direction, a rotor that operates the operating rod, a magnetic sensor that detects the displacement of the rotor, and a screw that converts the rotational movement of the rotor into the axial movement of the operating rod. It is equipped with a feed mechanism. The rotor includes a rotor core, a rotor magnet provided on the outer peripheral surface of the rotor core, and a sensor magnet provided at the shaft end portion of the rotor core. The magnetic sensor faces the sensor magnet in the axial direction and detects the displacement amount of the rotor by detecting the magnetic flux of the sensor magnet. The sensor magnet is provided with a hole along the axis.

According to this aspect, by providing the sensor magnet at the shaft end portion of the rotor core and providing the hole portion in the sensor magnet, a configuration in which the sensor magnet is connected to the rotor core instead of the operating rod and rotates is realized. As a result, the diameter of the hole can be adjusted regardless of the diameter of the operating rod.

According to the present invention, in an electric valve provided with a magnetic sensor, the degree of freedom in designing a sensor magnet to be detected can be increased.

It is sectional drawing which shows the electric valve which concerns on embodiment. It is a figure which shows the structure of a stator and its surroundings. It is a figure which shows the structure of a rotor. It is a figure which shows typically the action by making the sensor magnet the upper and lower two layers double-sided four poles. It is a figure which shows the analysis result which verified the influence which the size of the inner diameter of a sensor magnet has on the magnetic flux density sensed by a magnetic sensor. It is a figure which shows the structure of the rotor which concerns on the modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for convenience, the positional relationship of each structure may be expressed with reference to the illustrated state. Further, with respect to the following embodiments and variations thereof, substantially the same components are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 1 is a cross-sectional view showing an electric valve according to an embodiment.
The motorized valve 1 is applied to a refrigerating cycle of an automobile air conditioner (not shown). In this refrigeration cycle, a compressor that compresses the circulating refrigerant, a condenser that condenses the compressed refrigerant, an expansion valve that squeezes and expands the condensed refrigerant and sends it out in the form of a mist, and evaporates the mist-like refrigerant. An evaporator or the like that cools the air in the vehicle interior by the latent heat of evaporation is provided. The motorized valve 1 functions as an expansion valve for the refrigeration cycle.

The motorized valve 1 is configured by assembling a valve main body 2 and a motor unit 3. The valve body 2 has a body 5 that houses the valve portion. The body 5 functions as a "valve body". The body 5 is configured by coaxially assembling the first body 6 and the second body 8. Both the first body 6 and the second body 8 are made of stainless steel (hereinafter referred to as "SUS"). Since the valve seat 24 is provided on the second body 8, a material having excellent wear resistance is selected. The first body 6 has better weldability than the second body 8, and the second body 8 has better workability than the first body 6.

The first body 6 has a stepped cylindrical shape in which the outer diameter is gradually reduced downward. The outer diameter of the upper end portion of the first body 6 is slightly reduced to form a locking portion 52 due to a step. A male screw 10 for assembling the motorized valve 1 to a piping body (not shown) is formed on the lower outer peripheral surface of the first body 6. A pipe extending from the condenser side, a pipe connected to the evaporator, and the like are connected to the pipe body, but the details thereof will be omitted. A seal accommodating portion 12 formed of an annular groove is formed on the outer peripheral surface slightly above the male screw 10 in the first body 6, and a seal ring 14 (O-ring) is fitted therein.

A circular hole-shaped concave fitting portion 16 is provided at the lower portion of the first body 6. The second body 8 has a bottomed cylindrical shape, and the upper portion thereof is press-fitted into the concave fitting portion 16. A seal accommodating portion 18 formed of an annular groove is formed on the lower outer peripheral surface of the second body 8, and a seal ring 20 is fitted therein. A valve hole 22 is provided so as to penetrate the bottom of the second body 8 in the axial direction, and a valve seat 24 is formed at the upper end opening of the valve hole 22. An inlet port 26 is provided on the side of the second body 8, and an exit port 28 is provided on the lower portion. A valve chamber 30 is formed inside the first body 6 and the second body 8. The inlet port 26 and the outlet port 28 communicate with each other via the valve chamber 30.

An operating rod 32 extending from the rotor 60 of the motor unit 3 is inserted inside the body 5. The actuating rod 32 penetrates the valve chamber 30. The actuating rod 32 is obtained by cutting a bar made of a non-magnetic metal, and a needle-shaped valve body 34 is integrally provided below the rod. The valve body 34 is attached to and detached from the valve seat 24 from the valve chamber 30 side to open and close the valve portion.

A guide member 36 is erected in the center of the upper part of the first body 6. The guide member 36 is obtained by cutting a pipe material made of a non-magnetic metal into a stepped cylindrical shape, and a male screw 38 is formed on the outer peripheral surface of the central portion in the axial direction thereof. The lower end of the guide member 36 has a large diameter, and the large diameter portion 40 is press-fitted into the center of the upper part of the first body 6 and fixed coaxially. The guide member 36 slidably supports the operating rod 32 in the axial direction by its inner peripheral surface, while the rotary shaft 62 of the rotor 60 is slidably supported by its outer peripheral surface. The rotating shaft 62 is made of a non-magnetic metal.

A spring receiver 42 is provided slightly above the valve body 34 of the operating rod 32, and a spring receiver 44 is also provided at the bottom of the guide member 36. A spring 46 (functioning as an "urging member") that urges the valve body 34 in the valve closing direction is interposed between the spring receivers 42 and 44.

On the other hand, the motor unit 3 is configured as a three-phase stepping motor including a rotor 60 and a stator 64. The motor unit 3 has a bottomed cylindrical can 66, a rotor 60 is arranged inside the can 66, and a stator 64 is arranged outside the can 66. The can 66 is a bottomed cylindrical member that covers the space in which the valve body 34 and its drive mechanism are arranged and contains the rotor 60, and acts with the inner pressure space (internal space) on which the pressure of the refrigerant acts. It defines the outside non-pressure space (external space).

The can 66 is made of a non-magnetic metal (SUS in this embodiment), and is coaxially assembled so that the lower portion thereof is externally inserted into the upper end portion of the first body 6. The insertion amount of the can 66 is restricted by locking the lower end of the can 66 with the locking portion 52. By performing full-circle welding along the boundary between the lower end of the can 66 and the first body 6 (not shown), fixing and sealing of the body 5 and the can 66 are realized. The space surrounded by the body 5 and the can 66 forms the pressure space.

The stator 64 is configured by arranging a plurality of salient poles at equal intervals on the inner peripheral portion of the laminated core 70. The laminated core 70 is configured by laminating annular cores in the axial direction. A bobbin 74 to which a coil 73 (electromagnetic coil) is mounted is attached to each salient pole. The coil 73 and the bobbin 74 constitute a "coil unit 75". In this embodiment, three coil units 75 for supplying a three-phase current are provided every 120 degrees with respect to the central axis of the laminated core 70 (details will be described later).

The stator 64 is provided integrally with the case 76 of the motor unit 3. That is, the case 76 is obtained by injection molding (also referred to as "insert molding" or "mold molding") of a resin material having corrosion resistance. The stator 64 is covered with a mold resin obtained by injection molding thereof. The case 76 is made of the molded resin. Hereinafter, the molded product of the stator 64 and the case 76 is also referred to as a “stator unit 78”.

The stator unit 78 has a hollow structure and is assembled to the body 5 while the can 66 is coaxially inserted. A seal accommodating portion 80 formed of an annular groove is formed on the outer peripheral surface slightly below the locking portion 52 in the first body 6, and a seal ring 82 (O-ring) is fitted therein. By interposing the seal ring 82 between the upper outer peripheral surface of the first body 6 and the lower inner peripheral surface of the case 76, external atmosphere (water, etc.) can enter the gap between the can 66 and the stator 64. It is prevented.

The rotor 60 includes a cylindrical rotor core 102 assembled to the rotating shaft 62, a rotor magnet 104 provided on the outer peripheral surface of the rotor core 102, and a sensor magnet 106 provided on the upper end surface of the rotor core 102. The rotor core 102 is assembled to the rotating shaft 62. The sensor magnet 106 is coaxially assembled so as to be externally attached to the upper end portion of the rotor core 102. The rotor magnet 104 is magnetized (magnetized) to a plurality of poles in its circumferential direction. The sensor magnet 106 is also magnetized (magnetized) to a plurality of poles.

The rotary shaft 62 is a bottomed cylindrical cylindrical shaft, and is extrapolated to the guide member 36 with its open end facing down. A female screw 108 is formed on the lower inner peripheral surface of the rotating shaft 62 and meshes with the male screw 38 of the guide member 36. The rotary motion of the rotor 60 is converted into the axial motion of the operating rod 32 by the screw feed mechanism 109 by these screw portions. As a result, the valve body 34 moves (elevates) in the axial direction, that is, in the opening / closing direction of the valve portion.

The upper portion of the operating rod 32 is reduced in diameter, and the reduced diameter portion 110 penetrates the bottom portion 112 of the rotating shaft 62. An annular stopper 114 is fixed to the tip of the reduced diameter portion 110. On the other hand, a spring 116 that urges the operating rod 32 downward (that is, in the valve closing direction) is interposed between the base end of the reduced diameter portion 110 and the bottom portion 112. With such a configuration, when the valve is opened, the operating rod 32 is integrally displaced with the rotor 60 in such a manner that the stopper 114 is locked to the bottom 112. On the other hand, when the valve is closed, the spring 116 is compressed by the reaction force received by the valve body 34 from the valve seat 24. The elastic reaction force of the spring 116 at this time can press the valve body 34 against the valve seat 24, and the seating performance (valve closing performance) of the valve body 34 can be improved.

The motor unit 3 has a circuit board 118 on the outside of the can 66. The circuit board 118 is fixed to the inside of the case 76. In this embodiment, various circuits that function as a control unit and a communication unit are mounted on the lower surface of the circuit board 118. Specifically, the drive circuit for driving the motor, the control circuit (microcomputer) for outputting the control signal to the drive circuit, the communication circuit for the control circuit to communicate with the external device, each circuit and the motor (coil). A power supply circuit or the like for supplying power is mounted. The upper end of the case 76 is closed by the lid 77. The circuit board 118 is arranged in the space below the lid 77 in the case 76.

A magnetic sensor 119 is provided on the surface of the circuit board 118 facing the sensor magnet 106. The magnetic sensor 119 faces the sensor magnet 106 in the axial direction via the bottom end wall of the can 66. The magnetic flux generated by the sensor magnet 106 changes as the rotor 60 rotates. The magnetic sensor 119 detects the displacement amount of the rotor 60 (rotation angle of the rotor 60 in this embodiment) by capturing the change in the magnetic flux. The control unit calculates the axial position of the valve body 34 and thus the valve opening degree based on the displacement amount of the rotor 60.

A pair of terminals 117 connected to the coil 73 extend from each bobbin 74 and are connected to the circuit board 118. A power supply terminal, a ground terminal, and a communication terminal (collectively referred to as “connection terminal 81”) extend from the circuit board 118, and each of them penetrates the side wall of the case 76 and is drawn out to the outside. A connector portion 79 is integrally provided on the side portion of the case 76, and a connection terminal 81 is arranged inside the connector portion 79.

FIG. 2 is a diagram showing the configuration of the stator 64 and its surroundings. (A) corresponds to the cross section taken along the line AA of FIG. 1, and is a cross-sectional view of the stator unit 78. (B) is a figure showing only the stator 64 (state before resin molding). Note that FIG. 2A shows the can 66 and the rotor 60 for reference (see the alternate long and short dash line).

Since the motor unit 3 is a three-phase motor, as shown in FIG. 2A, coil units 75 are provided around the axis L of the rotor 60 at equal intervals. As shown in FIG. 2B, slots 120a to 120c (collectively referred to as “slot 120” when these are not particularly distinguished) are provided at intervals of 120 degrees with respect to the axis L on the inner peripheral portion of the laminated core 70. It is provided. In each slot 120, salient poles 122a to 122c (collectively referred to as “protruding poles 122”) projecting inward in the radial direction from the center thereof are formed, and are U-phase coil 73a, V-phase coil 73b, and W-phase coil 73c, respectively. (Generally referred to as "coil 73") is assembled. A slit 124 having a U-shaped cross section is also formed between the slots 120 adjacent to each other to optimize the magnetic path.

The rotor magnet 104 faces the salient poles 122a to 122c via the can 66. In this embodiment, as shown in FIG. 2A, the rotor magnet 104 is magnetized to 10 poles. The number of poles can be set as appropriate.

Next, the configuration of the magnet in the rotor 60 will be described in detail.
FIG. 3 is a diagram showing the configuration of the rotor 60. (A) is a perspective view, (B) is a front view, (C) is a plan view, and (D) is a sectional view taken along the line BB of (C). In the figure, "N" indicates N pole and "S" indicates S pole. In FIGS. 3A to 3C, the notation of the rotating shaft 62 is omitted for convenience of explanation.

The rotor 60 has a rotor magnet 104 along the outer peripheral surface of the rotor core 102, and a sensor magnet 106 is arranged at a shaft end portion of the rotor core 102 (FIGS. 3A and 3D). The rotor magnet 104 has a cylindrical shape and is magnetized with 10 poles on the outer peripheral surface (FIGS. 3 (B) and 3 (C)). On the other hand, the sensor magnet 106 has an annular shape and has two upper and lower layers, both sides of which are four-pole magnetized (one-sided two-pole magnetized on both sides). That is, the sensor magnet 106 is magnetized so that the upper layer 106a and the lower layer 106b each have two poles, and the polarities of the magnetic poles are reversed on both the upper and lower surfaces thereof. With such a configuration, the magnetic flux is strengthened.

The rotor core 102 is made of a cylindrical magnetic metal (magnetic material). An annular groove 140 is formed at the center of the rotor core 102 in the axial direction along the outer peripheral surface thereof (FIG. 3 (D)). The inner peripheral surface of the rotor magnet 104 is fitted in the annular groove 140. That is, the annular groove 140 functions as a dropout prevention structure for preventing the rotor magnet 104 from falling off from the rotor core 102.

The rotating shaft 62 has a reduced diameter portion 63 having a slightly reduced outer diameter at the upper portion thereof. The inner diameter of the shaft end portion 142 (upper end opening) of the rotor core 102 is slightly reduced so as to have a shape complementary to the reduced diameter portion 63, and constitutes a stopper in the axial direction when the rotor core 102 is assembled to the rotating shaft 62. ing.

The sensor magnet 106 is attached to the upper surface of the rotor core 102 while being extrapolated to the reduced diameter portion 63 of the rotating shaft 62. By arranging the sensor magnet 106 on the magnetic material (rotor core 102 in this embodiment) in this way, the magnetic force thereof can be increased. The washer 65 is coaxially inserted into the upper end of the rotating shaft 62, and the upper end is crimped so that the sensor magnet 106 is held between the shaft end 142 of the rotor core 102 and the washer 65.

Returning to FIG. 1, the motorized valve 1 configured as described above functions as an electric expansion valve whose valve opening degree can be adjusted by drive control of the motor unit 3. That is, based on a command from an external device (not shown), the control unit sets a control amount (number of motor drive steps) for achieving the target opening degree, and outputs a drive signal for achieving this to the drive circuit. do. The drive circuit supplies a three-phase drive current (drive pulse) at a timing set for each coil 73. As a result, the rotor 60 rotates with high resolution. At this time, if the valve body 34 is in the valve open state separated from the valve seat 24, the stopper 114 abuts on the rotating shaft 62 due to the urging force of the spring 116, and the operating rod 32 and thus the valve body 34 are integrated with the rotor 60. Operate.

The rotor 60 operates in the vertical direction by the screw feed mechanism 109 between the rotor 60 and the guide member 36. That is, the valve body 34 translates in the opening / closing direction of the valve portion, and the opening degree of the valve portion is adjusted to the set opening degree. The screw feed mechanism 109 converts the rotary motion around the axis of the rotor 60 into the axial motion (straight motion) of the operating rod 32, and drives the valve body 34 in the opening / closing direction of the valve portion. When the motorized valve 1 is attached to the piping body and functions as an expansion valve, the valve portion is controlled to a small opening degree.

The control unit can detect the rotation angle of the sensor magnet 106 (rotation angle of the rotor 60) based on the detection signal of the magnetic sensor 119 and calculate the valve opening degree.

Next, the action and effect of this embodiment will be described.
FIG. 4 is a diagram schematically showing the action of the sensor magnet 106 having four poles on both sides of two upper and lower layers. (A) shows the action of the embodiment, and (B) shows the action of the comparative example. A comparative example shows a case where the sensor magnet 126 has a two-pole structure of upper and lower layers. The two-dot chain arrow in the figure illustrates the direction of the magnetic flux in the sensor magnet.

In the present embodiment, since the sensor magnet 106 is magnetized on both sides (the magnetic poles have two upper and lower layers) and the polarities of the magnetic poles are reversed on both sides, the magnetic flux generated from one of the two sides is basically applied to the other. Be drawn in. On the other hand, in the comparative example, since the magnetic poles are in the upper and lower layers, a part of the magnetic flux generated from the magnetic poles of the sensor magnet 126 is drawn into the magnetic poles of the rotor magnet 104. That is, the magnetic field of the sensor magnet 126 may interfere with the magnetic field of the rotor magnet 104, and the balance of the magnetic flux between the rotor 60 and the stator 64 may be disturbed. In other words, according to the present embodiment, the balance of the magnetic fluxes between the rotor 60 and the stator 64 can be kept better than in the comparative example, and the rotation of the rotor 60 can be kept more stable.

FIG. 5 is a diagram showing analysis results for verifying the influence of the size of the inner diameter of the sensor magnet 106 on the magnetic flux density sensed by the magnetic sensor 119. The horizontal axis of the figure shows the distance between the magnetic sensor 119 and the sensor magnet 106, and the vertical axis shows the magnitude of the magnetic flux density. In this analysis, the results when the inner diameter of the sensor magnet 106 is changed by d1 to d5 (d1> d2> d3> d4> d5) are shown.

In the present embodiment, as shown in FIG. 1, the sensor magnet 106 has a hole 107, and the upper end portion of the rotating shaft 62, the stopper 114, and the upper end portion of the operating rod 32 are located inside the hole portion 107. The rotating shaft 62 and the operating rod 32 are provided coaxially, and the upper end portion of the rotating shaft 62 and the stopper 114 do not abut in the radial direction. That is, there is a radial gap between the sensor magnet 106 and the operating rod 32. In this analysis, it was verified that the hole 107 is provided in the sensor magnet 106 in such a configuration, and more specifically, the influence of the size of the inner diameter of the hole 107 on the detection of the magnetic flux by the magnetic sensor 119.

As shown in FIG. 5, as an overall tendency, the larger the distance between the sensor magnet 106 and the magnetic sensor 119, that is, the more the valve body 34 is displaced in the valve closing direction, the higher the magnetic flux density detected by the magnetic sensor 119. It turns out that it becomes smaller. That is, the closer the sensor magnet 106 is to the magnetic sensor 119, the larger the magnetic flux, and the farther away the sensor magnet 106 is, the smaller the magnetic flux. This in itself is a natural result. On the other hand, as the inner diameter of the sensor magnet 106 becomes larger, the change in the magnetic flux density becomes smaller, which is a new finding.

In the present embodiment, the inner diameter of the sensor magnet 106 is set in the range of d1 to d3, so that the change in the magnetic flux density due to the stroke of the operating rod 32, that is, the valve body 34 is suppressed to be small. That is, the magnetic sensor generally has a recommended range of the magnetic flux density to be sensed, and it is difficult to detect not only when the magnetic flux density is too small but also when the magnetic flux density is too large. In this respect, according to the present embodiment, the sensor sensitivity can be kept good by appropriately setting the inner diameter of the sensor magnet 106.

By this analysis, if the size of the hole 107 provided in the sensor magnet 106 is changed, the difference in magnetic flux density detected when the sensor magnet 106 and the magnetic sensor 119 are close to each other becomes large, but when they are separated from each other. It was found that the difference in the detected magnetic flux density can be suppressed to a small size. This means that by ensuring a sufficient size of the hole 107, the magnetic flux density does not become excessive when the two are close to each other, and the magnetic flux density when the two are separated can be sufficiently secured. do. That is, from the results of this analysis, it was confirmed that the sensor magnet 106 was provided with the hole 107 in the present embodiment and that the size of the hole 107 was increased to some extent.

As described above, according to the present embodiment, the magnetic flux can be strengthened by magnetizing the sensor magnet 106 with four poles on both sides (double-sided magnetizing with two poles on one side) and reversing the polarities of the magnetic poles on both sides. Therefore, even if the rotor 60 is displaced in the valve closing direction and the distance between the sensor magnet 106 and the magnetic sensor 119 increases, the sensitivity of the magnetic sensor 119 can be maintained satisfactorily.

On the other hand, by providing a hole 107 in the center of the sensor magnet 106 to secure a sufficient inner diameter thereof, even if the rotor 60 is displaced in the valve opening direction and the sensor magnet 106 is close to the magnetic sensor 119, the magnetic sensor 119 The magnetic flux density acting on the sensor is prevented from becoming excessive. That is, as described in relation to FIG. 5, the magnetic flux density acting on the magnetic sensor 119 can be kept within the recommended range regardless of the stroke of the valve body 34, and the sensitivity of the magnetic sensor 119 can be maintained satisfactorily.

Further, the sensor magnet 106 is magnetized with four poles on both sides (double-sided magnetism with two poles on one side), and the polarities of the magnetic poles are reversed on both sides thereof. Can be prevented or suppressed from interfering with the magnetic field of the rotor magnet 104. As a result, the rotation of the rotor 60 can be kept more stable.

Further, by providing the sensor magnet 106 at the shaft end portion of the rotor core 102 and providing the hole portion 107 in the sensor magnet 106, a configuration in which the sensor magnet 106 is connected to the rotor core 102 instead of the operating rod and rotates is realized. The magnet. As a result, the diameter of the hole 107 can be adjusted regardless of the diameter of the operating rod 32. That is, according to the present embodiment, the degree of freedom in designing the sensor magnet 106 can be increased.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and it goes without saying that various modifications can be made within the scope of the technical idea of the present invention. Nor.

FIG. 6 is a diagram showing a configuration of a rotor according to a modified example. (A) is a perspective view of a single sensor magnet. (B) is a perspective view of the rotor, (C) is a plan view, and (D) is a front view.
In this modification, the sensor magnet 206 is magnetized with 8 poles on both sides (double-sided magnetization with 4 poles on one side). That is, the sensor magnet 206 is magnetized so that the upper layer 206a and the lower layer 206b each have four poles, and the polarities of the magnetic poles are reversed on both the upper and lower surfaces thereof.

Even if such a configuration is adopted, since the sensor magnet 206 is magnetized on both sides and each surface has a plurality of magnetic poles, it is possible to suppress the influence of the magnetic field of the sensor magnet 206 on the rotor magnet 104. As a result, the stability of the rotor 260 can be improved as in the above embodiment.

In the above embodiment, an example is shown in which the rotor core 102 and the rotating shaft 62 are made of separate members in the rotor 60. In the modified example, the rotor core and the rotating shaft may be integrally molded, and a threaded portion (female screw 108) may be provided on the inner peripheral surface thereof. In that case, the rotor core also functions as a screw feed mechanism.

Although not described in the above embodiment, the rotor magnet 104 may be obtained by magnetizing a magnet portion integrally molded with the rotor core 102 in a post-process. Further, in the above embodiment, the rotor core 102 and the sensor magnet 106 are configured as separate members, and both are assembled. In the modified example, the sensor magnet 106 may also be obtained by magnetizing the magnet portion integrally molded with the rotor core 102 in a subsequent process. Both the rotor magnet portion and the sensor magnet portion may be integrally molded using the rotor core 102 as a base material and magnetized in a later process. In the molding of the magnet portion, a magnetic material may be injection molded. Alternatively, the magnet portion may be molded by forging, extrusion molding or other mold molding.

In the above embodiment, a configuration in which one sensor magnet 106 for double-sided magnetism is provided is exemplified. In the modified example, a plurality of double-sided magnetized sensor magnets may be arranged in series in the axial direction of the rotation axis.

In the above embodiment, the configuration in which the sensor magnet 106 is provided at the shaft end of the rotor core 102 is exemplified. In the modified example, the sensor magnet may be provided at the shaft end of the operating rod. Alternatively, a configuration may be adopted in which the sensor magnet is separated from the rotor core and fixed to the rotating shaft of the rotor.

In the above embodiment, a configuration in which the operating rod 32 is rotated coaxially with the rotor 60 is exemplified. In the modified example, a configuration in which the operating rod does not rotate may be adopted. For example, in the configuration shown in FIG. 1, a slide bearing may be provided between the stopper 114 and the rotor 60 to prevent the operating rod 32 from rotating. Further, the rotary motion of the rotor may be transmitted to the operating rod by a gear so that the axis of the operating rod does not match the axis of the rotor.

In the above embodiment, the configuration in which the upper end portions of the rotating shaft 62 and the operating rod 32 are inserted into the hole portion 107 of the sensor magnet 106 is exemplified. In the modified example, a configuration may be adopted in which either one or both of the rotating shaft of the rotor and the operating rod is not inserted into the hole 107 of the sensor magnet. In that case, the sensor magnet and the rotor core may be fitted and fixed by press fitting or other means.

In the above embodiment, the configuration in which the rotor 60 and the operating rod 32 are integrally displaced in the axial direction in the valve open state is shown. That is, the rotor 60 supports the operating rod 32 coaxially, and the rotor 60 itself is displaced in the axial direction. In the modified example, as described in Patent Document 1, a configuration in which the position of the rotor is fixed in the axial direction may be adopted. That is, a shaft that rotates integrally with the rotor and a driver that integrally has a valve body may be connected in the axial direction to form an operating rod. The driver rotates integrally with the shaft, but is capable of relative displacement in the axial direction. The rotary motion of the rotor is converted into the axial motion of the driver by the screw feed mechanism.

In the above embodiment, the magnetic sensor detects the rotation amount (rotation angle) of the rotor, and the control unit calculates the axial displacement of the operating rod (the stroke of the valve body, that is, the opening degree of the valve portion) based on the rotation amount. An example is shown. In the modified example, the magnetic sensor directly detects the axial displacement of the rotor (that is, the axial displacement of the operating rod), and the control unit calculates the stroke of the valve body (that is, the opening degree of the valve portion) based on the displacement. It is also good. That is, the magnetic sensor may detect the displacement amount of the rotor (that is, the displacement amount of the sensor magnet).

In the above embodiment, the configuration in which the rotor magnet 104 and the sensor magnet 106 are separated from each other in the axial direction is exemplified. In the modified example, the rotor magnet and the sensor magnet may be integrally configured. The rotor magnet portion and the sensor magnet portion may be integrally molded. In that case, the area (outer diameter) of the sensor magnet may be increased so that the magnetic sensor can reliably detect the magnetic flux.

Although not described in the above embodiment, the valve body and the piping body may be combined to form an “electric valve body”.

In each embodiment, a laminated core (laminated magnetic core) is exemplified as the core of the stator. In the modified example, a dust core or other core may be adopted. The dust core is also called a “dust core” and is obtained by kneading a powder obtained by powdering a soft magnetic material and coating it with a non-conductive resin or the like and a resin binder, and compression molding and heating.

In each embodiment, a configuration in which a drive circuit, a control circuit, a communication circuit, and a power supply circuit are mounted on the lower surface of a circuit board is exemplified, but the mounted circuit can be appropriately changed. For example, the drive circuit and the power supply circuit may be mounted, while the control circuit may be installed outside the motorized valve. Further, each circuit may be mounted on the upper surface of the circuit board.

In each embodiment, a PM type stepping motor is adopted as the motor unit, but a hybrid type stepping motor may be adopted. Further, in the above embodiment, the motor unit is a three-phase motor, but other motors such as two-phase, four-phase, and five-phase may be used. The number of electromagnetic coils in the stator is not limited to three or six, and may be appropriately set according to the number of phases of the motor.

The motorized valve of each embodiment is suitably applied to a refrigerating cycle using an alternative chlorofluorocarbon (HFC-134a) as a refrigerant, but it can also be applied to a refrigerating cycle using a refrigerant having a high working pressure such as carbon dioxide. Is. In that case, an external heat exchanger such as a gas cooler is arranged in place of the condenser in the refrigeration cycle.

In each embodiment, the motorized valve is configured as an expansion valve, but it may be configured as an on-off valve or a flow rate control valve that does not have an expansion function.

In each embodiment, an example in which the above-mentioned electric valve is applied to a refrigeration cycle of an automobile air conditioner is shown, but it can be applied not only to a vehicle but also to an air conditioner equipped with an electric expansion valve. It can also be configured as an electric valve that controls the flow of a fluid other than the refrigerant.

In the above embodiment, the configuration in which the sensor magnet 106 is magnetized on both the upper and lower sides and the polarities of the magnetic poles are reversed at the corresponding positions on both sides is illustrated. That is, in the sensor magnet 106, the boundary lines of the magnetic poles coincide with each other on the upper and lower surfaces. In the modified example, a sensor magnet in which the magnetic poles on both the upper and lower sides are not inverted at a part of the position may be adopted. That is, the boundary lines of the magnetic poles do not completely coincide with each other on the upper and lower surfaces, and may be slightly deviated. In that case, since the upper and lower surfaces have the same polarity at some positions, the effect may be inferior to that of the above embodiment, but there is a possibility that an effect that does not cause a problem in actual use can be obtained.

The present invention is not limited to the above-described embodiment or modification, and the components can be modified and embodied within a range that does not deviate from the gist. Various inventions may be formed by appropriately combining a plurality of components disclosed in the above embodiments and modifications. In addition, some components may be deleted from all the components shown in the above embodiments and modifications.

1 electric valve, 2 valve body, 3 motor unit, 5 body, 22 valve hole, 24 valve seat, 26 inlet port, 28 outlet port, 30 valve chamber, 32 actuating rod, 34 valve body, 36 guide member, 38 male screw, 46 springs, 60 rotors, 62 rotating shafts, 63 reduced diameter parts, 64 stators, 65 washers, 66 cans, 70 laminated cores, 73 coils, 76 cases, 78 stator units, 102 rotor cores, 104 rotor magnets, 106 sensor magnets, 106a Upper layer, 106b lower layer, 107 holes, 108 female threads, 109 screw feed mechanism, 114 stopper, 116 spring, 118 circuit board, 119 magnetic sensor, 126 sensor magnet, 142 shaft end, 206 sensor magnet, 206a upper layer, 206b lower layer.

Claims (4)

An actuating rod that supports the valve body in the axial direction,
The rotor that operates the operating rod and
A magnetic sensor that detects the displacement of the rotor and
A screw feed mechanism that converts the rotary motion of the rotor into the axial motion of the operating rod,
Equipped with
The rotor is
With the rotor core
A rotor magnet provided on the outer peripheral surface of the rotor core and
The sensor magnet provided at the shaft end of the rotor core and
Including
The magnetic sensor faces the sensor magnet in the axial direction, and detects the displacement amount of the rotor by detecting the magnetic flux of the sensor magnet.
An electric valve characterized in that the sensor magnet is provided with a hole along an axis. The screw feed mechanism displaces the rotor in the axial direction together with the operating rod.
The motorized valve according to claim 1, wherein the sensor magnet is brought close to or separated from the magnetic sensor by the operation of the screw feed mechanism. A cylindrical member containing the rotor, further provided with a can that defines an internal space on which fluid pressure acts and an external space on which fluid pressure does not act.
The magnetic sensor is arranged in the external space,
The motorized valve according to claim 1 or 2, wherein the sensor magnet and the magnetic sensor face each other via the end wall of the can. The motorized valve according to any one of claims 1 to 3, wherein the sensor magnet is provided on a magnetic material.

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