Compound valve control device

Abstract

To downsize a composite valve.SOLUTION: A composite valve 1 includes: a first valve 10 having a large diameter; a second valve 12 having a diameter that is smaller than that of the first valve 10; and a single solenoid 3 for driving the first valve 10 and the second valve 12 to open and close them. Energization control to the solenoid 3 controls the opening of the second valve 12, whereby the second valve 12 works as an expansion valve.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to a composite valve including a large-diameter valve and a small-diameter valve. [[Background Art]]

[0002] With the popularization of electric vehicles in recent years, the development of air conditioning systems for such vehicles has also been promoted. Since electric vehicles do not have a heat source provided by an internal combustion engine, a heat pump type air conditioning device that performs cycle operation using a refrigerant for not only cooling but also heating is employed.

[0003] Such a vehicle air conditioning device has a refrigeration cycle including a compressor, an outdoor heat exchanger, an expansion device, an evaporator, an indoor heat exchanger, and the like, and the refrigerant circulation passage is switched between heating operation and cooling operation. That is, since a plurality of refrigerant circulation passages are formed, the number of control valves for controlling the flow of refrigerant also increases. For this reason, it is important that these control valves can be accommodated as compactly as possible within the limited space of a vehicle.

[0004] Accordingly, a composite valve has been proposed in which a plurality of control valves are assembled to a common body to form a unit. The valve portions of the respective control valves are accommodated in the common body, and each valve portion is driven to open and close by a single actuator. According to such a composite valve, the overall size is more compact than when each control valve is provided as a separate unit.

[0005] Specifically, a composite valve (motor-operated valve) in which a large-diameter valve (also referred to as "large-diameter valve") and a small-diameter valve (also referred to as "small-diameter valve") are driven by a single motor has been proposed (see Patent Document 1). If such a composite valve is disposed in the refrigerant circulation passage, the small-diameter valve can function as an expansion valve, while the large-diameter valve can function as an on-off valve. [[Prior Art Document]] [[Patent Document]]

[0006] [[Patent Document 1]] Japanese Patent Publication No. 2020-41596 [Overview of the project] [Problems that the invention aims to solve]

[0007] Such composite valves have complex mechanisms, such as a screw feed mechanism that converts the rotational motion of the rotor into the translational motion of the valve body, which tends to result in larger actuators and greater weight. There was room for improvement in this respect.

[0008] One of the objectives of this invention is to achieve a more compact composite valve. [Means for solving the problem]

[0009] One aspect of the present invention is a composite valve. This composite valve comprises a first valve with a large diameter, a second valve with a smaller diameter than the first valve, and a single solenoid that drives the first and second valves to open and close. The opening degree of the second valve is controlled by the energization control of the solenoid, and the second valve functions as an expansion valve.

[0010] According to this embodiment, since a solenoid is used as a shared actuator for the first and second valves, the combined valve can be made more compact compared to the case where a motor is used.

[0011] Another aspect of the present invention is a composite valve control device. This composite valve control device comprises a composite valve that drives the opening and closing of a large-diameter first valve and a small-diameter second valve with a single solenoid, and a control unit that controls the current supplied to the solenoid. The composite valve includes a body on which a first valve seat is formed, a first valve body that is detachable from the first valve seat to open and close the first valve, a second valve seat provided in the internal passage of the first valve body, a second valve body that is detachable from the second valve seat to open and close the second valve, and an operating coupling mechanism that couples or uncouples the operation of the first valve body and the second valve body according to the energization state of the solenoid, and couples the operation of the second valve body and the first valve body when the second valve is fully open. The solenoid is energized using a PWM method during the process of changing the opening degree of the first valve and the second valve, respectively. The control unit temporarily increases the rate of change of the current supplied to the solenoid in a predetermined stroke region of the first valve body where the first valve is partially open.

[0012] In this embodiment, since a solenoid is used as a shared actuator for the first and second valves, the composite valve can be made more compact compared to when a motor is used. Furthermore, since a PWM method is used for the energization control of the solenoid, the first valve, especially the large-diameter one, is prone to noise problems caused by the first valve body striking the first valve seat (so-called valve tapping) due to minute vibrations during partial opening. In this aspect, by temporarily increasing the rate of change of the current supplied to the solenoid, the stroke region where valve tapping is likely to occur can be quickly exited, and the generation of noise can be prevented or suppressed. In other words, it becomes easier to avoid problems that may arise when using a solenoid as an actuator. [Effects of the Invention]

[0013] The present invention aims to achieve a more compact composite valve. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional view showing the structure of a composite valve according to the first embodiment. [Figure 2] This is a magnified view of a part illustrating the operation of a compound valve. [Figure 3]It is a diagram showing the valve opening characteristics of a composite valve. [Figure 4] It is a cross-sectional view schematically showing the structure of a composite valve according to a modified example. [Figure 5] It is a cross-sectional view schematically showing the structure of a composite valve according to a second embodiment. [Figure 6] It is a partially enlarged view showing the operation of the composite valve. [Figure 7] It is a diagram showing the valve opening characteristics of the composite valve. [Figure 8] It is a cross-sectional view schematically showing the structure of a composite valve according to a modified example. [Figure 9] It is a diagram showing energization control when the composite valve is a normally open valve. [Figure 10] It is a diagram showing energization control when the composite valve is a normally closed valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] 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 based on the illustrated state. In addition, in the following embodiments and their modified examples, substantially identical components are denoted by the same reference numerals, and descriptions thereof are omitted as appropriate.

[0016] First Embodiment FIG. 1 is a cross-sectional view schematically showing the structure of a composite valve according to the first embodiment. The composite valve 1 is applied to a heat pump type air conditioning apparatus for a vehicle. This air conditioning apparatus has a refrigeration cycle including a compressor, an outdoor heat exchanger, an expansion device, an evaporator, an indoor heat exchanger, and the like, and the function of the outdoor heat exchanger is switched between a heating operation and a cooling operation. During the heating operation, the outdoor heat exchanger functions as an evaporator. At that time, the indoor heat exchanger dissipates heat in the process of the refrigerant circulating through the refrigeration cycle, and the heat warms the air in the vehicle compartment. During the cooling operation, the outdoor heat exchanger functions as a condenser. At that time, the refrigerant condensed in the outdoor heat exchanger is decompressed and expanded by the expansion device to become a gas-liquid two-phase refrigerant, and is evaporated in the evaporator. The latent heat of evaporation cools the air in the vehicle compartment.

[0017] The composite valve 1 is disposed, for example, between an indoor heat exchanger and an outdoor heat exchanger. It functions as an on-off valve that opens and closes the refrigerant circulation passage during cooling operation, and functions as an expansion valve that throttles and expands refrigerant flowing through the refrigerant circulation passage during heating operation.

[0018] The composite valve 1 includes a large-diameter first valve 10 (large-diameter valve) and a small-diameter second valve 12 (small-diameter valve), and these valves are driven to open and close by a single solenoid 3. The composite valve 1 functions as an on-off valve by opening and closing the first valve 10, and functions as an expansion valve by adjusting the opening degree of the second valve 12. The composite valve 1 is a so-called normally open valve, and both the first valve 10 and the second valve 12 are fully opened when the solenoid 3 is off (non-energized).

[0019] The composite valve 1 is configured by assembling a body 2 and a solenoid 3 in the axial direction. A valve hole 14 (first valve hole) is provided on the axial line of the body 2, and a valve seat 16 (first valve seat) is formed at the downstream opening of the valve hole.

[0020] The solenoid 3 includes a stepped cylindrical core 20 coaxially assembled to the body 2, a bottomed cylindrical sleeve 22 (non-magnetic material) coaxially assembled to the core 20, a plunger 24 accommodated inside the sleeve 22 and axially opposed to the core 20, and an electromagnetic coil 26 wound around the outer circumference of the sleeve 22. Since this figure is a schematic diagram, the structure of the connection between the body 2 and the core 20 is omitted from the illustration.

[0021] The connection portion of the core 20 with the body 2 has an enlarged diameter, and a valve body 30 (first valve body) is disposed inside the enlarged diameter portion. A guide hole 28 is formed by the inner circumferential surface of the enlarged diameter portion. The valve body 30 has a bottomed cylindrical shape and is slidably supported by the guide hole 28. The first valve 10 is opened and closed when the valve body 30 is attached to and detached from the valve seat 16 from the downstream side. Meanwhile, a valve hole 32 (second valve hole) is formed in the middle of the internal passage of the valve body 30. A valve seat 34 (second valve seat) is formed at the upstream opening of the valve hole 32.

[0022] The valve body 30 is a bottomed cylindrical shape with a sufficiently thick bottom. A back pressure chamber 36 is formed on the back of the valve body 30 (opposite the valve hole 14). The back pressure chamber 36 is a space enclosed by the core 20 and the valve body 30. A valve chamber 38 is formed inside the valve body 30. A disc-shaped engaging member 40 is fixed to the end of the valve body 30. The engaging member 40 has an insertion hole 42 in its center.

[0023] Multiple communication holes 31 (small holes) are provided in the bottom of the valve body 30, penetrating parallel to the axis. The upstream openings of these communication holes 31 serve as inlet ports 33. The communication holes 31 connect the valve hole 14 and the valve chamber 38. The communication holes 31, the valve chamber 38, and the insertion hole 42 constitute a "communication passage" that connects the valve hole 14 and the back pressure chamber 36. In addition, a downstream passage 35 extending perpendicular to the axis is provided in the bottom of the valve body 30. The downstream passage 35 has an outlet port 37 that opens toward the downstream side of the valve hole 14. A seal ring 39 (O-ring) is fitted to the outer circumferential surface of the valve body 30, restricting the flow of refrigerant through the gap between the valve body 30 and the guide hole 28. In a modified example, a communication hole connecting the valve chamber 38 and the back pressure chamber 36 may be provided in the valve body 30, separate from the insertion hole 42.

[0024] An operating rod 44 extends from the plunger 24 and passes coaxially through the core 20. A valve body 46 (second valve body) is provided at the tip of the operating rod 44. The operating rod 44 slidably passes through the insertion hole 42 of the valve body 30, and the valve body 46 is positioned inside the valve chamber 38. The second valve 12 is opened and closed by the valve body 46 attaching to and detaching from the valve seat 34 from the upstream side. A spring 48 (biasing member) is interposed between the plunger 24 and the core 20 to bias the operating rod 44 in the direction of opening the valve body 46. The spring 48 functions as a so-called "off spring" to fully open the first valve 10 (large-diameter valve) when the solenoid 3 is not energized.

[0025] In this embodiment, the valve body 46 has a tapered attachment / detachment portion 47 that attaches to and detaches from the valve seat 34, and a spool portion 49 that is inserted into and removed from the valve hole 32. In the stroke region where the spool portion 49 is inserted into the valve hole 32 and the attachment / detachment portion 47 is detached from the valve seat 34, the opening degree of the second valve 12 is maintained at a constant small opening degree (hereinafter, this state will also be referred to as the "spool state").

[0026] A spring retainer 50 is provided on the operating rod 44, projecting radially near the valve body 46, and an engaging member 52 is provided to engage with the spring retainer 50. The spring retainer 50 is made of, for example, an E-ring. The engaging member 52 is cylindrical and is coaxially fitted onto and fixed to the operating rod 44. One end face of the engaging member 52 (the end face opposite to the spring retainer 50) is engageable (detachable) with one end face of the engaging member 40. A spring 54 (biasing member) is interposed between the bottom of the valve body 30 and the spring retainer 50 to bias the valve body 30 in the closing direction (the direction in which the engaging member 40 and the engaging member 52 engage).

[0027] As shown in the figure, by engaging the engaging member 40 and the engaging member 52, the valve body 46 and the valve body 30 can be connected via the operating rod 44 so that they can be displaced as a single unit, that is, they can be operatedly connected. In other words, the engaging member 40 provided on the valve body 30, the engaging member 52 provided on the operating rod 44, and the spring 54 provided between the valve body 30 and the engaging member 52 constitute an "operational connection mechanism" that connects or disconnects the operation of the valve body 30 and the valve body 46.

[0028] Next, we will explain the operation of the control valve. In this embodiment, a PWM (Pulse Width Modulation) method is employed to control the energization of the solenoid 3. PWM control involves supplying a pulse current of a predetermined frequency (for example, around 400 Hz) to control the energization, and the supplied current value is changed by changing the duty cycle of the pulse current. The control unit 100 performs this energization control.

[0029] The control unit 100 outputs a pulse signal set to a predetermined duty cycle to the drive circuit 102, causing the drive circuit 102 to output a current pulse corresponding to that duty cycle to drive the solenoid 3. The control unit 100 includes a CPU for executing various calculation processes, a ROM for storing various control programs, a RAM used as a work area for data storage and program execution, an input / output interface, etc. The control unit 100 has a PWM output unit that outputs a pulse signal with a specified duty cycle, but since its configuration is a known one, a detailed explanation is omitted. The composite valve 1, the control unit 100, and the drive circuit 102 constitute a "composite valve control device".

[0030] Figure 2 is a partially enlarged view showing the operation of the compound valve 1. Figure 2(A) shows the state where both the first valve 10 and the second valve 12 are open, Figure 2(B) shows the state where the first valve 10 is closed and the second valve 12 is open, and Figure 2(C) shows the state where both the first valve 10 and the second valve 12 are closed. The following explanation will be based on Figure 1, with reference to Figure 2 as appropriate.

[0031] In the composite valve 1, when the solenoid 3 is de-energized (off), no suction force acts between the core 20 and the plunger 24. On the other hand, the biasing force of the spring 48 acts to move the plunger 24 away from the core 20. This biasing force is transmitted to the valve body 46 via the operating rod 44. As a result, the second valve 12 opens completely (Figure 2(A)). At this time, the engaging member 52 engages with the engaging member 40, and the operating rod 44 lifts the valve body 30, so the first valve 10 also opens completely. This opens the refrigerant circulation passage.

[0032] When control current is supplied to solenoid 3, core 20 attracts plunger 24. As a result, the operating rod 44 is biased in the closing direction of the first valve 10 and the second valve 12. At this time, by increasing the duty cycle of the PWM control, the current supplied to solenoid 3 can be increased, and the first valve 10 (large-diameter valve) can be operated in the closing direction (Figure 2(B)). Because the valve body 46 is biased in the opening direction by the load of spring 54, the second valve 12 remains fully open until the first valve 10 closes.

[0033] By further increasing the duty cycle and thus increasing the current supplied to the solenoid 3, the second valve 12 (small-bore valve) can be operated in the closing direction while maintaining the closed state of the first valve 10 (Figure 2(C)). At this time, by controlling the opening degree of the second valve 12 by adjusting the duty cycle, the composite valve 1 can be made to function as an expansion valve.

[0034] Figure 3 shows the valve opening characteristics of composite valve 1. The horizontal axis of the figure represents the current supplied to the solenoid, and the vertical axis represents the valve opening degree. For the sake of explanation, Figures 2(A) to (C) are labeled A to C in Figure 3 to show the correspondence with the operation process.

[0035] The operation of each valve shown in Figure 2 is expressed as the control characteristics shown in Figure 3. That is, from zero to the first current value I1 supplied to the solenoid 3, both the first valve 10 and the second valve 12 remain fully open (Figure 2(A)). When the supplied current value exceeds the first current value I1, the valve body 30 operates in the closing direction while the second valve 12 remains fully open, and the opening degree of the first valve 10 changes. When the supplied current value reaches the second current value I2, the valve body 30 seats on the valve seat 16, and the first valve 10 becomes closed (fully closed) (Figure 2(B)). Therefore, the opening degree of the first valve 10 can be controlled by adjusting the supplied current value between the first current value I1 and the second current value I2. This energized control region in which the opening degree of the first valve 10 is variable is also called the "large-diameter valve control region".

[0036] When the supplied current value exceeds the second current value I2, the valve body 46 operates in the closing direction while the first valve 10 remains closed, and the opening degree of the second valve 12 changes. When the supplied current value exceeds the third current value I3, the spool portion 49 of the valve body 46 enters a spool state where it is inserted into the valve hole 32. This energization control region where the valve is in this spool state is also called the "spool region".

[0037] When the supplied current value further reaches the fourth current value I4, the attachment / detachment portion 47 of the valve body 46 seats on the valve seat 34, completely closing the second valve 12 to a fully closed state (Figure 2(C)). Therefore, the opening degree of the second valve 12 can be controlled by adjusting the supplied current value between the second current value I2 and the third current value I3. This energization control region in which the opening degree of the second valve 12 is variable is also called the "small-diameter valve control region". When the second valve 12 is to function as an expansion valve, the supplied current value is set near the third current value I3.

[0038] In the illustrated example, the relationship between the supply current value and the valve opening degree is a constant proportional relationship in the large-diameter valve control region. However, this slope of the valve opening characteristic can be changed by setting the load of the spring 48 (selection of the spring constant). By reducing the load of the spring 48, a valve opening characteristic can be obtained in which the valve opening degree changes in a step-like manner when a predetermined set current value is reached, making it easier to make the first valve 10 function as an on / off valve. Specifically, current value I1 ≈ current value I2, and a valve opening characteristic can be obtained in which the opening degree of the large-diameter valve changes instantaneously from fully open to fully closed or from fully closed to fully open when a predetermined set current value is reached.

[0039] Similarly, in the small-diameter valve control region, the relationship (slope) between the supply current value and the valve opening degree can be adjusted by setting the load of the spring 54 (selection of the spring constant). In this embodiment, it is necessary to be able to control the second valve 12 at a small opening degree in order for it to function as an expansion valve. For this reason, the load of the spring 54 is made greater than the load of the spring 48, and the slope of the valve opening characteristic in the small-diameter valve control region is made gentler, as shown in the figure.

[0040] As described above, in this embodiment, the large-diameter first valve 10 and the small-diameter second valve 12 are driven to open and close by a single solenoid 3, so that the first valve 10 functions as an on-off valve and the second valve 12 functions as an expansion valve. For this reason, there is no need to provide an operating conversion mechanism that converts rotation to translation, as is the case when a motor is used as the actuator, and the composite valve 1 can be realized in a compact form.

[0041] [Differentiation] Figure 4 is a schematic cross-sectional view showing the structure of a modified composite valve. The composite valve 101 of this modified example differs from the first embodiment in the arrangement structure of the off-spring. Specifically, there is no spring between the core 20 and the plunger 24, and a spring 148 is disposed between the valve body 130 (first valve body) and the body 2 to bias the valve body 130 in the opening direction. More specifically, a flange portion 132 is provided projecting radially outward from the outer circumferential surface of the valve body 130, and a spring 148 is interposed between the flange portion 132 and the body 2. The spring 148 functions as an off-spring. Similar to the first embodiment, the load of the spring 54 is set to be greater than the load of the spring 148.

[0042] In this modified example, the solenoid 3 is used as a shared actuator for the first valve 10 and the second valve 12, so the same effects as in the first embodiment can be obtained.

[0043] [Second Embodiment] Figure 5 is a schematic cross-sectional view showing the structure of a composite valve according to the second embodiment. The composite valve 201 of this embodiment is a so-called normally closed valve, and differs from the first embodiment in that both the first valve 10 and the second valve 12 are closed when the solenoid 203 is off (not energized). The composite valve 201 comprises a first valve 10 (large diameter valve) and a second valve 12 (small diameter valve), and these valves are opened and closed by a single solenoid 203.

[0044] The composite valve 201 is constructed by assembling the body 2 and the solenoid 203 in the axial direction. The solenoid 203 comprises a bottomed cylindrical yoke 230 coaxially mounted to the body 2, a core 220 coaxially mounted to the yoke 230 via a cylindrical sleeve 222 (non-magnetic material), a plunger 224 housed inside the sleeve 222 and axially opposite to the core 220, and an electromagnetic coil 26 wound around the sleeve 222 and the core 220. The positional relationship between the core 220 and the plunger 224 with respect to the valve body 30 differs from that of the first embodiment. Note that this figure is a schematic diagram, and therefore the structure of the connection between the body 2 and the yoke 230 is not shown.

[0045] A guide hole 28 is formed by the inner circumferential surface of the yoke 230, and the valve body 30 is slidably supported therein. An insertion hole 235 is provided in the center of the bottom of the yoke 230. An operating rod 244 extends from the plunger 224 and passes through the insertion hole 235. A valve body 46 is provided at the tip of the operating rod 244. The space enclosed by the yoke 230 and the valve body 30 forms a back pressure chamber 36. A spring 248 (biasing member) is interposed between the bottom of the yoke 230 and the valve body 30 in the back pressure chamber 36 to bias the valve body 30 in the closing direction.

[0046] A flange portion 53 is provided at one end of the engaging member 52 (the end opposite to the engaging member 40) that protrudes radially outward. A spring 254 (biasing member) is interposed between the flange portion 53 and the engaging member 40 to bias the valve body 46 in the closing direction (the direction that separates the engaging member 40 and the engaging member 52). The engaging member 40, the engaging member 52, and the spring 254 constitute an "operation coupling mechanism" that connects or disconnects the operation of the valve body 30 and the valve body 46. In this embodiment, the load of the spring 248 is set to be greater than the load of the spring 254.

[0047] Next, we will explain the operation of the control valve. Figure 6 is a partially enlarged view showing the operation of the composite valve 201. Figure 6(A) shows the state where both the first valve 10 and the second valve 12 are closed, Figure 6(B) shows the state where the first valve 10 is closed and the second valve 12 is open, and Figure 6(C) shows the state where both the first valve 10 and the second valve 12 are open. The following explanation will be based on Figure 5, with reference to Figure 6 as appropriate.

[0048] In the composite valve 201, when the solenoid 203 is de-energized (off), no suction force acts between the core 220 and the plunger 224. On the other hand, the spring 248 biases the valve body 30 in the closing direction. Furthermore, the spring 254 biases the valve body 46 in the closing direction. This biasing force also acts in the direction that separates the plunger 24 from the core 20. As a result, both the first valve 10 and the second valve 12 are in the closed state (fully open state) (Figure 6(A)). This blocks the refrigerant circulation passage.

[0049] When a control current is supplied to the solenoid 3, the core 220 attracts the plunger 224. As a result, the valve body 46 moves in the opening direction together with the operating rod 244. At this time, the opening degree of the second valve 12 can be controlled by adjusting the duty cycle of the PWM control, thereby allowing the composite valve 201 to function as an expansion valve. Since the load of the spring 248 is set to be greater than the load of the spring 254, the first valve 10 remains closed until the second valve 12 is fully open (Figure 6(B)).

[0050] By increasing the duty cycle and thus the current supplied to the solenoid 203, the valve body 30 can be opened against the biasing force of the spring 248 (Figure 6(C)). At this time, the engaging member 52 engages with the engaging member 40, and the operating rod 244 lifts the valve body 30. By switching the duty cycle between the closed state and the fully open state of the first valve 10, the composite valve 201 can be made to function as an on-off valve.

[0051] Figure 7 shows the valve opening characteristics of the composite valve 201. The horizontal axis of the figure represents the current supplied to the solenoid, and the vertical axis represents the valve opening. For the sake of explanation, Figures 6(A) to (C) are labeled A to C in Figure 7 to show the correspondence with the operation process.

[0052] The operation of each valve shown in Figure 6 is expressed as the control characteristics shown in Figure 7. That is, when the solenoid 203 is off, both the first valve 10 and the second valve 12 are in a closed state (fully closed state) (Figure 6(A)). When the solenoid 203 is energized, the first valve 10 remains in a closed state and the second valve 12 remains in a spool state until the supply current value reaches the first current value I11. When the supply current value exceeds the first current value I11, the opening degree of the second valve 12 increases in proportion to the current value. The first valve 10 remains in a closed state. When the supply current value reaches the second current value I12, the second valve 12 becomes fully open (Figure 6(B)).

[0053] Therefore, the opening degree of the second valve 12 can be controlled by adjusting the supply current value between the first current value I11 and the second current value I12. This energization control region in which the opening degree of the second valve 12 is variable is also called the "small-diameter valve control region." When the second valve 12 is to function as an expansion valve, the supply current value is set to a value close to the first current value I11.

[0054] The slope of this valve opening characteristic can be changed by the load setting (selection of spring constant) of the spring 254. By increasing the load of the spring 254 and making the slope of the valve opening characteristic in the small-diameter valve control region gentler, as shown in the figure, it becomes easier to control the second valve 12 at a small opening and to make it function as an expansion valve.

[0055] When the supplied current value exceeds the second current value I12, the valve body 30 operates in the opening direction while the second valve 12 remains fully open, and the opening degree of the first valve 10 changes. When the supplied current value reaches the third current value I13, the first valve 10 becomes fully open. Therefore, the opening degree of the first valve 10 can be controlled by adjusting the supplied current value between the second current value I12 and the third current value I13. This energization control region in which the opening degree of the first valve 10 is variable is also called the "large-diameter valve control region".

[0056] In the illustrated example, the relationship between the supply current value and the valve opening degree is a constant proportional relationship in the large-diameter valve control region, but this slope of the valve opening characteristic can change depending on the load setting (selection of spring constant) of spring 248.

[0057] As described above, in this embodiment as well, the large-diameter first valve 10 and the small-diameter second valve 12 are driven to open and close by a single solenoid 203, so that the first valve 10 functions as an on-off valve and the second valve 12 functions as an expansion valve. For this reason, as in the first embodiment, there is no need to provide an operating conversion mechanism that converts rotation to translation, as would be the case when a motor is used as the actuator, and the composite valve 201 can be realized in a compact form.

[0058] [Differentiation] Figure 8 is a schematic cross-sectional view showing the structure of a modified composite valve. The composite valve 301 in this modified example differs from the second embodiment in its biasing structure for biasing the valve body 330 (first valve body) in the closing direction. The composite valve 301 does not have a spring 248 like the second embodiment, and the valve body 330 is biased in the closing direction by the pressure (differential pressure) of the refrigerant acting on the valve body 330.

[0059] In other words, by providing a step 332 on the outer surface of the valve body 330, the pressure-receiving diameter φA of the back pressure received by the valve body 330 is made slightly larger than the pressure-receiving diameter φB of the seal portion of the valve body 330 (φA > φB). As a result, the differential pressure (P1-P2) between the upstream pressure P1 and the downstream pressure P2 acts on the valve body 330 in the closing direction, with respect to the pressure-receiving area corresponding to this difference in pressure-receiving diameters (φA-φB). Consequently, the valve body 330 is biased in the closing direction.

[0060] However, since the difference in pressure-receiving diameter is minute, the fluid pressure acting on the valve body 330 is almost completely canceled out. Therefore, the resistance when pulling the valve body 330 in the opening direction can be reduced, and the increase in the solenoid force required to open the first valve 10 can be suppressed.

[0061] In this modified example, the solenoid 203 is used as a shared actuator for the first valve 10 and the second valve 12, so the same effects as in the second embodiment can be obtained.

[0062] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these specific embodiments, and various modifications are possible within the scope of the technical concept of the present invention.

[0063] [Other variations] Although not mentioned in the embodiments described above, when a PWM method is used for controlling the energization of the solenoid, a problem of abnormal noise is likely to occur due to the valve body striking the valve seat (so-called valve tapping) when both large-diameter and small-diameter valves are partially open. The abnormal noise tends to be particularly loud for large-diameter valves. Therefore, in the modified examples, measures are taken to counteract the abnormal noise by devising a way to control the energization of the solenoid.

[0064] Figure 9 shows the energization control when the composite valve is normally open. Figure 9(A) shows the valve opening characteristics of the composite valve and corresponds to Figure 3. The horizontal axis shows the current supplied to the solenoid, and the vertical axis shows the valve opening. Figure 9(B) shows the energization control method. The horizontal axis shows the stroke of the valve body from the fully open state to the closed state, and the vertical axis shows the duty cycle set by PWM control.

[0065] In this modified example, as shown in Figure 9(A), when the first valve 10 is partially open (large-diameter valve partially open region), the change in the duty cycle is temporarily increased, as shown in Figure 9(B). That is, the control unit 100 temporarily increases the rate of increase of the current supplied to the solenoid in a predetermined stroke region of the valve body 30 where the first valve 10 is partially open (large-diameter valve partially open region), causing the first valve 10 to instantly transition from the partially open state to the closed state. In the illustrated example, the rate of increase is temporarily increased from the fifth current value I5, which is near the second current value I2. As a result, the first valve 10 can quickly exit the stroke region where valve tapping is likely to occur, and the generation of abnormal noise can be prevented or suppressed.

[0066] Furthermore, when the second valve 12 is partially open (small-diameter valve partially open region), the change in the duty cycle is temporarily increased. That is, even in the predetermined stroke region of the valve body 46 where the second valve 12 is partially open (small-diameter valve partially open region), the control unit 100 temporarily increases the rate of increase of the current supplied to the solenoid, causing the second valve 12 to instantly transition from the partially open state to the closed state. In the illustrated example, the rate of increase of the duty cycle is temporarily increased from the sixth current value I6, which is near the fourth current value I4. As a result, the second valve 12 can quickly exit the stroke region where valve tapping is likely to occur, and the generation of abnormal noise can be prevented or suppressed.

[0067] The starting point for increasing the rate of increase in the supplied current is set based on the vibration amplitude of each valve body controlled by PWM. For example, the starting point may be when the current value reaches a predetermined stroke position where the lift amount from each valve seat of each valve body is greater than its vibration amplitude.

[0068] The same applies when opening a composite valve (normally open valve) from a closed state. When the same small-diameter valve half-open region and large-diameter valve half-open region are reached, the rate of decrease in the duty cycle is temporarily increased. Specifically, the energization control shown in Figure 9(B) should be followed in the reverse direction from when closing the valve. That is, in both the opening and closing operations of a composite valve (normally open valve), the rate of change of the current supplied to the solenoid should be temporarily increased in the predetermined stroke region of each valve body where the small-diameter valve and large-diameter valve are in a half-open state.

[0069] Figure 10 shows the energization control when the composite valve is a normally closed valve. Figure 10(A) shows the valve opening characteristics of the composite valve and corresponds to Figure 7. The horizontal axis shows the current supplied to the solenoid, and the vertical axis shows the valve opening. Figure 10(B) shows the energization control method. The horizontal axis shows the stroke of the valve body from the fully closed state to the opening direction, and the vertical axis shows the duty cycle set by PWM control.

[0070] In this modified example, as shown in Figure 10(A), the change in the duty cycle is temporarily increased in the partially open region of the second valve 12 (small diameter valve partially open region), as shown in Figure 10(B). That is, the control unit 100 temporarily increases the rate of increase of the current supplied to the solenoid in the stroke region of the valve body 46 where the second valve 12 is partially open (small diameter valve partially open region), causing the second valve 12 to instantly transition from the closed state to the open state. In the illustrated example, the rate of increase of the duty cycle is temporarily increased from the start of energization until the fourth current value I14. As a result, the stroke region in which valve tapping is likely to occur in the second valve 12 can be quickly exited, and the generation of abnormal noise can be prevented or suppressed.

[0071] Furthermore, when the first valve 10 is partially open (large-diameter valve partially open region), the change in the duty cycle is temporarily increased. That is, even in the stroke region of the valve body 30 where the first valve 10 is partially open (large-diameter valve partially open region), the control unit 100 temporarily increases the rate of increase of the current supplied to the solenoid, causing the first valve 10 to instantly transition from the closed state to the open state. In the illustrated example, the rate of increase of the duty cycle is temporarily increased until the fifth current value I15 is near the second current value I12. This allows the first valve 10 to quickly exit the stroke region where valve tapping is likely to occur, thereby preventing or suppressing the generation of abnormal noise.

[0072] The endpoint for increasing the rate of increase of the supplied current is set based on the vibration amplitude of each valve body controlled by PWM. For example, the endpoint may be set when the current value reaches a predetermined stroke position where the lift amount from each valve seat of each valve body is greater than its vibration amplitude.

[0073] The same applies when the composite valve (normally closed valve) is operated to close from an open state. When the same small-diameter valve slightly open region and large-diameter valve slightly open region are reached, the reduction rate of the duty ratio is temporarily increased. That is, the energization control shown in Fig. 10(B) may be traced in the reverse direction to that during the valve opening operation. That is, in both the valve opening operation and the valve closing operation of the composite valve (normally closed valve), the rate of change of the current supplied to the solenoid may be temporarily increased in a predetermined stroke region of each valve body where each of the small-diameter valve and the large-diameter valve is in a slightly open state.

[0074] It should be noted that, as a method for suppressing valve hammering in the slightly open region of each valve, besides temporarily increasing the amount of change in the duty ratio as described above, it is also conceivable to temporarily change the frequency of PMW control (PWM frequency). For example, when the supply current value increases, the PWM frequency may be temporarily increased from the first frequency f1 to the second frequency f2 (f1 < f2). Thereby, the current amplitude can be reduced in the slightly open region, and valve hammering can be suppressed.

[0075] Alternatively, it is also conceivable to temporarily switch from PWM control to DC control when the slightly open region of each valve is reached. In that case, a PWM control circuit and a DC control circuit may be provided as the drive circuit, and the control unit may switch between them. Thereby, current amplitude can be eliminated in the slightly open region, and valve hammering can be suppressed.

[0076] In the above embodiment, an example in which the composite valve is applied to a heat pump type air conditioning apparatus for vehicles has been described, but it goes without saying that the composite valve can also be applied to non-heat pump type refrigeration cycles employed in engine vehicles and the like.

[0077] The motor-operated valve of the above embodiment is suitably applied to a refrigeration cycle using an alternative chlorofluorocarbon (HFC-134a) or the like as a refrigerant, but can also be applied to a refrigeration cycle using a refrigerant with a high operating pressure such as carbon dioxide. In that case, an external heat exchanger such as a gas cooler is arranged in the refrigeration cycle instead of a condenser.

[0078] In the above embodiment, an example was shown in which the electric valve is applied to the refrigeration cycle of an automotive air conditioning system. However, it is applicable to air conditioning systems equipped with an electric expansion valve, not limited to vehicles. It may also be configured as an electric valve to control the flow of fluids other than refrigerants, such as hot water in a hot water supply system or hydraulic fluid (hydraulic oil) in a hydraulic control device.

[0079] It should be noted that the present invention is not limited to the embodiments and modifications described above, and the components can be modified and implemented without departing from the spirit of the invention. Various inventions may be formed by appropriately combining the multiple components disclosed in the embodiments and modifications described above. In addition, some components may be deleted from all the components shown in the embodiments and modifications described above. [Explanation of Symbols]

[0080] 1 Compound valve, 2 Body, 3 Solenoid, 10 First valve, 12 Second valve, 14 Valve bore, 16 Valve seat, 20 Core, 24 Plunger, 26 Electromagnetic coil, 28 Guide bore, 30 Valve body, 31 Communication hole, 32 Valve bore, 33 Inlet port, 34 Valve seat, 35 Downstream passage, 36 Back pressure chamber, 37 Outlet port, 38 Valve chamber, 39 Seal ring, 40 Engaging member, 42 Through hole, 44 Actuating rod, 46 Valve body, 47 Detachable part, 48 Spring, 49 Spool part, 52 Engaging member, 54 Spring, 101 Compound valve, 130 Valve body, 148 Spring, 201 Compound valve, 203 Solenoid, 220 Core, 224 Plunger, 230 Yoke, 244 Actuating rod, 248 Spring, 254; Spring, 301; Compound valve, 330; Valve body, 332; Step.

Claims

1. A composite valve that drives the opening and closing of a large-diameter first valve and a small-diameter second valve with a single solenoid, A control unit that controls the current supplied to the solenoid, Equipped with, The aforementioned composite valve is The body on which the first valve seat is formed, A first valve body that is attached to and detached from the first valve seat to open and close the first valve, A second valve seat provided in the internal passage of the first valve body, A second valve body that attaches to and detaches from the second valve seat to open and close the second valve, An operating coupling mechanism that connects or disconnects the operation of the first valve body and the second valve body according to the energization state of the solenoid, and connects the operation of the second valve body and the first valve body when the second valve is fully open, Includes, The solenoid is energized using a PWM method during the process of changing the opening degree of the first valve and the second valve, respectively. The control unit is characterized by temporarily increasing the rate of change of the current supplied to the solenoid in a predetermined stroke region of the first valve body in which the first valve is partially open.

2. The composite valve control device according to claim 1, characterized in that the control unit temporarily increases the rate of change of the current supplied to the solenoid in a predetermined stroke region of the second valve body in which the second valve is partially open.

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