Valve device

Abstract

This invention provides a valve device that improves the driving efficiency of the valve core by suppressing the frictional resistance during rotor rotation. The driving part (5) of the valve device (1) includes: a cylindrical shell (50); an external thread (55) serving as a driving shaft; an internal thread component (56) engaging with the external thread; a guide component (54) fixedly disposed in the cylindrical shell and guiding the internal thread component forward and backward; and a bearing component (53) disposed inside the cylindrical shell and providing rotational support for the external thread. A cylindrical first shaft portion (55b) and a second shaft portion (55c) (shaft portion) are respectively provided at both ends of the external thread. A first bearing hole (53c1) and a second bearing hole (54a) (bottomed concave hole) are respectively provided at the shaft core position of the external thread on the guide component and the bearing component (53). The first shaft portion (55b) is inserted into the first bearing hole (53c1), and the second shaft portion (55c) is inserted into the second bearing hole (54a), thereby providing rotational support for the external thread.

Description

Technical Field

[0001] This invention relates to a valve device. Background Technology

[0002] Conventionally, valve devices used in refrigeration cycles and the like have been known to include a cylindrical valve body, a valve core slidably disposed inside the valve body, a valve seat portion disposed in the valve body and having a valve port, and a drive portion for slidingly driving the valve core along an axial direction (for example, see Patent Document 1). In the valve device described in Patent Document 1, the drive portion includes: a stepper motor; a support shaft that supports the rotor of the stepper motor; a support member that rotatably supports the upper end of the support shaft by inserting it through; a rotor support member that is fixed to the upper part of the rotor; an output shaft that rotatably supports the lower end of the support shaft by inserting it through; and a reduction mechanism disposed between the rotor and the output shaft, which reduces the rotation of the rotor by the reduction mechanism to rotate the output shaft, thereby performing direct conversion of the rotation of the output shaft, and thus driving the valve core forward and backward.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-199921 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the valve device described above, the movement of the support shaft in the axial direction in the drive unit is restricted by the surface contact between the rotor support member and the support member. As a result, the frictional resistance increases when the rotor rotates, and the driving efficiency of the valve core caused by the stepper motor decreases.

[0008] The purpose of this invention is to provide a valve device that can improve the driving efficiency of the valve core by reducing the frictional resistance during rotor rotation.

[0009] Solution for solving the problem

[0010] The valve device of the present invention comprises: a hollow cylindrical valve body; a valve seat portion disposed on the valve body and having a valve port; a valve core slidably disposed inside the valve body along an axial direction; and a drive portion for slidingly driving the valve core. The valve device is characterized in that the drive portion comprises: a motor portion having a rotatable rotor; a bottomed cylindrical housing fixed to the valve body and housing the rotor; an external thread fixed to the rotor and extending in an axial direction; an internal thread component screwed into the external thread and capable of moving forward and backward in an axial direction with rotation of the external thread; a guide component configured to be immobile relative to the housing and guiding the internal thread component forward and backward; and a bearing component disposed inside the bottom side of the housing and rotatably supporting the external thread. Cylindrical shaft portions are respectively provided at both ends of the external thread. Bottomed recesses are provided at the shaft core positions of the external threads of the guide component and the bearing component, and the shaft portions at both ends of the external thread are respectively inserted into each of the recesses, thereby rotatably supporting the external thread.

[0011] According to this invention, cylindrical shaft portions are provided at both ends of an external thread fixed to the rotor and extending along the axial direction. Each shaft portion is inserted into a bottomed recess formed in a guide member and a bearing member, thereby providing rotational support for the external thread. In this way, by supporting the cylindrical shaft portions at both ends of the external thread in the bottomed recesses, the external thread and the rotor can be supported for free rotation while reducing the frictional resistance between the shaft portions and the recesses. Furthermore, by reducing the frictional resistance during rotor rotation, the attenuation of the motor output can be suppressed, thus obtaining a valve device that improves the driving efficiency of the valve core. In addition, according to this structure, the external thread, which engages with the internal thread member that moves along the axial direction, is supported by the bearing member and the guide member and its movement in the direction intersecting the axial direction is restricted. Therefore, even if impacts or vibrations are applied from the outside, the vibration of the external thread, the internal thread member, and the valve core can be suppressed, reducing the impact on the valve body's operation caused by contact between the rotor and the housing. Furthermore, the bottom of each recess restricts the movement of the external thread in the axial direction.

[0012] Preferably, at least three radially projecting protrusions are provided on the outer periphery of the bearing component, which can abut against the inner surface of the housing. According to this structure, when the bearing component is inserted into the housing, it is not inserted around its entire circumference, but rather with at least three protrusions in contact. Therefore, the bearing component can be inserted into the housing under low load, and concentricity between the housing and the bearing component can be ensured.

[0013] Furthermore, preferably, the inner diameter of the recess is larger than the outer diameter of the shaft, and a conical surface is formed at the bottom of the recess. According to this structure, by forming a conical surface at the bottom of the recess, the shaft portion of the external thread is centered by the conical surface. Additionally, by making the inner diameter of the recess larger than the outer diameter of the shaft, it is difficult for the shaft portion to contact the recess, allowing the external thread to rotate more smoothly and reducing the frictional resistance of the shaft portion within the recesses of the bearing components and guide components.

[0014] Furthermore, it is preferable that the front end of the shaft portion at least one of the two ends of the external thread is provided with a spherical surface. According to this structure, the external thread can contact the bottom of the concave hole via the spherical surface provided at the front end of the shaft portion, thereby further reducing the contact area with the bottom of the concave hole, thereby enabling the external thread to rotate smoothly with low torque.

[0015] Furthermore, preferably, the length between the two front ends of the shaft portion of the external thread is less than the length from the bottom of one of the recesses to the bottom of the other recess, and a gap is provided between the front end of at least one of the shaft portions and the bottom of the recess. According to this structure, since a gap is provided between the front end of at least one of the shaft portions of the external thread and the bottom of the recess, the shaft portion of the external thread can be prevented from being pressed down by the bottom of each recess, allowing the external thread to rotate smoothly.

[0016] Alternatively, a force-applying component can be provided between the bottom of the housing and the bearing component, which applies force to the bearing component toward the guide component. According to this structure, by applying force to the bearing component and the external thread toward the guide component, the axial portion of the bearing component and the external thread is pressed toward the guide component, shortening the length from the bottom of one recess to the bottom of another. This eliminates the gap between the bottom of the recess and the axial portion of the external thread. Therefore, looseness between the recess and the axial portion of the external thread can be eliminated.

[0017] Furthermore, preferably, the guide member supports the internally threaded component so that it cannot rotate about the axis. According to this structure, the guide member can support the internally threaded component so that it cannot rotate but can move forward and backward. Thus, by means of the guide member, the internally threaded component, and the external thread, a direct-acting mechanism can be constructed that converts the rotational motion of the rotor into motion in the axial direction.

[0018] Furthermore, the valve core can be formed as a bowl-shaped recess with an elongated oval shape in the axial direction. The opening edge of the bowl-shaped recess serves as a sealing portion, which can slide in contact with the sealing surface of the valve seat. The valve seat has multiple valve ports that open onto the sealing surface. According to this structure, in valve devices such as sliding switching valves that have a valve core with a bowl-shaped recess and multiple valve ports, it is possible to reduce frictional resistance while supporting the external thread and rotor for free rotation, and to suppress vibrations of the external thread, internal thread components, and valve core, thereby reducing the impact on the operation of the valve body.

[0019] Invention Effects

[0020] According to the present invention, by reducing the frictional resistance during rotor rotation, a valve device that can improve the driving efficiency of the valve core can be obtained. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a valve device according to an embodiment of the present invention.

[0022] Figure 2 This is an enlarged sectional view of the drive unit.

[0023] Figure 3 (A) is an enlarged sectional view of the shaft portion and bearing assembly with external threads. Figure 3 (B) is an enlarged sectional view of the shaft and guide component of the external thread.

[0024] Figure 4 yes Figure 1 A sectional view along the AA line.

[0025] Figure 5 It is a 3D view of the bearing components.

[0026] Figure 6 This is an enlarged sectional view of the external thread and bearing components in the first variation.

[0027] Figure 7 This is an enlarged sectional view of the external thread and guide component in the second variation.

[0028] In the picture:

[0029] 1—Valve assembly; 2—Valve body; 3—Valve seat; 4—Valve core; 5—Drive unit; 5a—Stepper motor (motor unit); 50—Cylindrical shell (bottomed cylindrical shell); 51—Magnetic rotor (rotor); 53—Bearing component; 53c1—First bearing hole (bottomed recess); 54—Guide component; 54a—Second bearing hole (bottomed recess); 55—External thread; 55b—First shaft; 55c—Second shaft; 56—Internal thread component; L—Axis. Detailed Implementation

[0030] The following is based on Figures 1-5 Embodiments of the present invention will be described. The valve device 1 of this embodiment is a sliding switching valve connected to a compressor, evaporator, and condenser in a refrigeration cycle or similar device, and used to switch the flow path of the refrigerant flowing in these devices. The valve device 1 includes: a hollow cylindrical valve body 2; a valve seat 3 disposed on the valve body 2 and having multiple valve ports; a valve core 4 slidably disposed inside the valve body 2 in the axial direction L; and a drive unit 5 for slidingly driving the valve core 4. Furthermore, in this embodiment, Figures 1-3 The vertical direction in the diagram is used as the vertical direction in valve device 1. That is, one side of the axis L of valve device 1 is designated as the upper side, and the other side as the lower side. This is only for illustrative purposes and does not necessarily correspond to the vertical direction of valve device 1 in its actual use, nor does it limit the vertical direction of valve device 1 in its actual use.

[0031] The valve body 2 is formed into a bottomed cylindrical shape using resin material, extending upward from its front end, and its interior forms a valve chamber 2a. An inlet port A is formed on the bottom wall of the valve body 2, communicating with both the inside and outside of the valve chamber 2a. Inlet port A is a port communicating with the outlet of a compressor (not shown) via an inlet connecting flow path 20 extending along the axis L. This inlet port A constitutes the inlet for high-pressure refrigerant supplied from the compressor to flow into the valve chamber 2a. On the side wall of the valve body 2, as multiple cylindrical flow paths communicating with both the inside and outside of the valve chamber 2a, a first connecting flow path 21, an outlet connecting flow path 22, and a second connecting flow path 23 are formed sequentially from the top along the axis L. The first connecting flow path 21 is a flow path communicating with the first port 30 (described later). This first connecting flow path 21 is connected to the condenser (or evaporator) to form a flow path for fluid flowing between the condenser (or evaporator) and the valve chamber 2a.

[0032] The outlet connection flow path 22 is a flow path that communicates with the outlet port 31 described later. This outlet connection flow path 22 is connected to the compressor's suction port, forming a flow path for low-pressure refrigerant returning to valve chamber 2a via the first connection flow path 21 (or the second connection flow path 23) to be sent to the compressor. The second connection flow path 23 is a flow path that communicates with the second port 32 described later. This second connection flow path 23 is connected to the evaporator (or condenser) to form a flow path for fluid flowing between the evaporator (or condenser) and valve chamber 2a. A metal cylindrical lower cover 24 is fixed to the upper end of the valve body 2 by forming an insert with the valve body 2, and a metal bottomed cylindrical upper cover 25 with a bottom wall on the upper end of the lower cover 24 is fixed to the upper end of the lower cover 24.

[0033] The upper cover 25 has a small-diameter portion 25a extending upward in the direction of axis L at the center of its bottom wall. A through hole 25b extending in the direction of axis L is formed in the center of the small-diameter portion 25a, and a guide member 54, described later, is disposed in the through hole 25b. The valve body 2, lower cover 24, and upper cover 25 thus configured are housed in a housing (not shown). It should be noted that... Figure 1 The symbol G represents grooves formed at predetermined intervals at multiple locations along the axis L on either the outer peripheral wall of the valve body 2 or the inner peripheral wall of the outer shell. Symbol 26 represents an O-ring disposed in the groove G. This O-ring 26 seals the valve body 2 against the outer shell. In this embodiment, the valve body 2 is made of a resin such as polyphenylene sulfide (PPS), but it can also be made of suitable materials such as brass, iron, aluminum, or stainless steel.

[0034] The valve seat portion 3 is a portion of the side wall of the valve body 2 that has a first connecting flow path 21, an outlet connecting flow path 22, and a second connecting flow path 23, and is configured to have multiple valve ports. This valve seat portion 3 is formed from a thin metal sheet and is fixed to the side wall of the valve body 2 by insert forming, bonding, welding, etc. A first port 30 communicating with the first connecting flow path 21, an outlet port 31 communicating with the outlet connecting flow path 22, and a second port 32 communicating with the second connecting flow path 23 are respectively formed on the plate surface of the valve seat portion 3. Each port 30, 31, and 32 is formed into a cylindrical shape with an inner diameter smaller than that of the first connecting flow path 21, the outlet connecting flow path 22, and the second connecting flow path 23, and is arranged at predetermined intervals along the axis L. The surface of the valve seat portion 3 opposite to the side containing each connecting flow path 21, 22, and 23 forms a sealing surface 33 that slides in contact with the sealing portion S of the valve core 4, described later. Therefore, multiple valve ports 30, 31, and 32 open on the sealing surface 33.

[0035] The valve core 4 is mainly made of resin such as polyphenylene sulfide (PPS) and is slidably disposed inside the valve body 2 along the axis L. The valve core 4 is configured as a bowl-shaped valve core body 40 that sits on the valve seat 3 and connects or separates the inlet port A, the first port 30, the outlet port 31, and the second port 32. The valve core body 40 is configured with: an elongated oval-shaped opening edge 40a that is positioned opposite the sealing surface 33 of the valve seat 3 and is longer along the axis L; and a bowl-shaped portion 40b that protrudes from the opening edge 40a to the side opposite to the valve seat 3, the interior of which forms a bowl-shaped recess 40c that serves as a flow path for fluid. The dimension of the opening edge 40a in the bowl-shaped recess 40c along the axis L is set to cover the length of two adjacent ports among the first port 30, the outlet port 31, and the second port 32. In addition, the width of the opening edge 40a intersecting the axis L direction is set to be long enough to cover one of the first port 30, the outlet port 31, and the second port 32.

[0036] The opening edge 40a of the bowl-shaped recess 40c constitutes a sealing portion S capable of sliding contact with the sealing surface 33. When the sealing portion S abuts against the sealing surface 33, for example, the first port 30 and the outlet port 31 are surrounded by the bowl-shaped recess 40c and isolated from the other ports A and 32. As a result, the first port 30 is connected to the outlet port 31, and the inlet port A is connected to the second port 32. Furthermore, if the sealing portion S slides downward while sliding on the sealing surface 33, the outlet port 31 and the second port 32 are surrounded by the bowl-shaped recess 40c and isolated from the other ports A and 30. As a result, the outlet port 31 is connected to the second port 32, and the inlet port A is connected to the first port 30. That is, the valve core body 40 slides, and the sealing portion S slides into contact with the sealing surface 33, thereby switching the connection and isolation between the ports A, 30, 31, and 32.

[0037] A base 41 is formed on the sidewalls at both ends of the bowl-shaped recess 40c in the width direction. A longer fitting groove 41a in the axis L direction is formed on each base 41. Furthermore, a reinforcing member 6 is disposed within the bowl-shaped recess 40c, embedded from one fitting groove 41a to the other. The reinforcing member 6 is a component that suppresses deformation of the sidewalls of the bowl-shaped recess 40c due to the pressure difference between the high-pressure valve chamber 2a and the low-pressure bowl-shaped recess 40c. The reinforcing member 6 is disposed on the inner side of both sidewalls in the width direction of the bowl-shaped recess 40c. The reinforcing member 6 is configured to have a rectangular planar portion 60 in the width direction along the axis L and a pair of vertical upper portions 61 rising from both ends of the planar portion 60 in the width direction. The planar portion 60 and the vertical upper portions 61 are integrally formed using sheet metal components by methods such as stamping. Figure 1As shown, the planar portion 60 is configured such that its bottom surface faces the sealing surface 33 and has a predetermined gap in the direction facing the sealing surface 33. A pair of upright upper portions 61 are respectively provided on the inner surfaces of the two side walls along the width direction of the bowl-shaped recess 40c. The upright upper portions 61 are formed in a rectangular shape that is longer in the axial direction L so as to fit into the aforementioned fitting groove 41a. If the upright upper portion 61 fits into the fitting groove 41a, the reinforcing member 6 is positioned in the bowl-shaped recess 40c.

[0038] A spring member 42 is provided at the top of the bowl-shaped portion 40b of the valve core body 40, applying force to the valve core body 40 towards the valve seat portion 3. One end of the spring member 42 abuts against the inner peripheral wall of the valve body 2, and the other end abuts against the top of the valve core body 40, situated between the valve body 2 and the valve core body 40. A stop 43 is formed at the lower end of the valve core body 40, protruding downwards in the direction of the axis L. This stop 43 is a protrusion used to restrict the sliding movement of the valve core 4, and restricts the downward movement of the valve core 4 by abutting its protruding end against the surface of the valve chamber 2a side in the bottom wall of the valve body 2. That is, the stop 43 and the surface of the valve chamber 2a side in the bottom wall of the valve body 2 define the limit position that the valve core 4 can move downwards.

[0039] A connecting portion 44 protruding upward is formed at the upper end of the valve core body 40. The upper end of the connecting portion 44 is a thin plate portion 44a extending from the side where the valve seat portion 3 is located toward the opposite side of the side where the valve seat portion 3 is located along an axis intersecting the axis L. A cutout 44b is formed in the thin plate portion 44a opening toward the side opposite to the side where the valve seat portion 3 is located, thereby making the thin plate portion 44a hook-shaped. The two end faces of the thin plate portion 44a in the width direction are clamped in the width direction by the two connecting arms 56b of the internally threaded member 56, which will be described later. In this state, it is connected to the internally threaded member 56 by a fixing pin 59 disposed in the cutout 44b and a metal hose band 45 that surrounds the connecting arms 56b and the thin plate portion 44a in the circumferential direction and is fastened in the same direction.

[0040] The drive unit 5 is the part that slides and drives the valve core 4, and includes: a stepper motor 5a (motor unit) which is an electric motor having a rotatable rotor; and a linear motion mechanism 5b that converts the rotation of the stepper motor 5a into linear motion and transmits it to the valve core 4. Figure 1As shown, the stepper motor 5a includes: a bottomed cylindrical shell 50 made of metal, fixed to the small-diameter portion 25a of the upper cover 25 and sealing the drive unit 5; a magnet rotor 51 (rotor) built into the cylindrical shell 50; and a stator coil 52 arranged to surround the outer periphery of the magnet rotor 51 around the axis L, with the cylindrical shell 50 in between. The cylindrical shell 50 is formed of a thin sheet of metal into a bottomed cylindrical shape, with the bottom wall disposed on the upper side, and the front end fixed to the upper edge of the small-diameter portion 25a of the upper cover 25 by welding or the like. That is, the cylindrical shell 50 is fixed to the valve body 2 via the upper cover 25. Moreover, by fixing the cylindrical shell 50 to the upper cover 25 in this way, the cylindrical shell 50 and the guide member 54 described later are arranged coaxially with the axis L of the valve body 2. The direct-acting mechanism 5b includes: a bearing member 53 disposed inside the bottom (upper) side of the cylindrical shell 50; a guide member 54 fixed to the upper cover 25; an external thread 55 serving as the rotor shaft, fixed to the center of the magnet rotor 51 via a fixing member 55a; and an internal thread member 56 having an internal thread portion 56a1 that engages with the external thread portion 55d formed on the outer peripheral surface of the external thread 55. In other words, the direct-acting mechanism 5b is configured as a threaded feed mechanism having mutually engaging external thread portion 55d and internal thread portion 56a1.

[0041] The bearing component 53 supports the external thread 55 so that it can rotate about the axis L. It includes a cylindrical large-diameter portion 53a, a cylindrical first small-diameter portion 53b protruding upward from the center of the large-diameter portion 53a, and a cylindrical second small-diameter portion 53c protruding downward from the center of the large-diameter portion 53a. The large-diameter portion 53a, the first small-diameter portion 53b, and the second small-diameter portion 53c are integrally formed and arranged coaxially with the central axis and the axis L within the cylindrical shell 50. Figure 4 As shown, the large-diameter portion 53a is formed such that its diameter is slightly smaller than the inner diameter of the cylindrical shell 50. For example... Figure 5 As shown, a plurality of (three in this embodiment) radially outward protrusions 53a1 are formed at intervals in the circumferential direction on the outer peripheral wall of the large-diameter portion 53a. The protrusions 53a1 are portions capable of abutting against the inner wall surface of the cylindrical shell 50. The radial dimension from the center of the large-diameter portion 53a to the front end of the protrusion 53a1 is set to be approximately the same as or slightly larger than the radial dimension from the center of the cylindrical shell 50 to the inner wall portion. With this structure, as... Figure 4 As shown, by inserting the large-diameter portion 53a into the cylindrical shell 50, the front end of the protrusion 53a1 in the large-diameter portion 53a presses against the inner wall of the cylindrical shell 50, and the outer peripheral wall of the large-diameter portion 53a and the inner wall of the cylindrical shell 50 are separated by a gap in the radial direction, and the bearing component 53 is fixed inside the cylindrical shell 50.

[0042] The first minor diameter portion 53b is the part that restricts the upward movement of the bearing component 53, and it is formed with a diameter smaller than that of the major diameter portion 53a. For example... Figure 1 As shown, when the bearing component 53 is inserted into the cylindrical shell 50, the upper end of the first small-diameter portion 53b is positioned by abutting against the inner surface of the bottom wall of the cylindrical shell 50. In the bearing component 53, a first bearing hole 53c1 opening downwards is formed at the center of the external thread 55. The first bearing hole 53c1 is a bottomed recessed hole that allows insertion of the first shaft portion 55b (described later). It opens at the lower end face of the second small-diameter portion 53c and extends into the first small-diameter portion 53b through the large-diameter portion 53a along the axis L. The inner peripheral wall of the first bearing hole 53c1 is cylindrical, forming a first conical surface 53c2 with its bottom inclined upwards. Figure 3 As shown in (A), the inner diameter of the first bearing hole 53c1 is formed to be larger than the outer diameter of the first shaft portion 55b.

[0043] The guide member 54 is a bottomed cylindrical component, disposed within the through hole 25b of the upper cover 25 with its bottom located on the lower side and its front end on the upper side. The guide member 54 has a retaining ring 57 integrally formed by insert molding at approximately its center along the axis L. This retaining ring 57 is fixed to the upper cover 25 by welding it to the upper edge of the small-diameter portion 25a of the upper cover 25. In other words, the guide member 54 is configured such that it cannot move relative to the cylindrical shell 50. The guide member 54 is configured with its central axis coaxial with the axis L of the valve body 2. This configuration ensures that the cylindrical shell 50, the bearing component 53, and the guide member 54 are all coaxial with the axis L of the valve body 2.

[0044] In the guide member 54, a second bearing hole 54a, opening upwards, is formed at the center of the axis of the external thread 55. The second bearing hole 54a is a bottomed recessed hole provided such that the second shaft portion 55c (described later) can be inserted. It opens into the inner surface of the bottom wall of the guide member 54 and extends along the axis L. The inner peripheral wall of the second bearing hole 54a is formed in a cylindrical shape, constituting a conical second conical surface 54a1 with a bottom inclined downwards. Figure 3 As shown in (B), the inner diameter of the second bearing hole 54a is formed to be slightly larger than the outer diameter of the second shaft portion 55c. Furthermore, as... Figure 2As shown, a pair of guide holes 54b are formed on the bottom wall of the guide member 54, on the radially outer side of the second bearing hole 54a, allowing the connecting arm portion 56b of the internally threaded member 56 (described later) to be inserted and retracted along the axis L. These guide holes 54b are formed radially opposite each other across the second bearing hole 54a. The edges of the guide holes 54b have a shape that follows the outer wall surface of the connecting arm portion 56b. Furthermore, even if the connecting arm portion 56b needs to rotate around the axis L when retracting along the axis L, it cannot rotate because its outer wall surface abuts against the edges of the guide holes 54b. That is, the guide member 54 is configured to prevent the internally threaded member 56 from rotating around the axis L and to guide its retraction and retraction along the axis L.

[0045] The external thread 55 is configured to be fixed to the center of the magnet rotor 51 by a fixing member 55a, extending along the axis L and rotating integrally with the magnet rotor 51 around the axis L. The upper end of the external thread 55 forms a cylindrical first shaft portion 55b (shaft portion), and the lower end of the external thread 55 forms a cylindrical second shaft portion 55c (shaft portion). An external thread portion 55d is formed on the outer peripheral surface of the portion between the first shaft portion 55b and the second shaft portion 55c. Furthermore, the first shaft portion 55b is inserted into the first bearing hole 53c1, and the second shaft portion 55c is inserted into the second bearing hole 54a. Thus, the external thread 55 is supported in the first bearing hole 53c1 and the second bearing hole 54a in a manner that allows the central shaft to rotate around the axis L, so that the central shaft is coaxial with the axis L. The length from the front end of the first shaft portion 55b to the front end of the second shaft portion 55c, i.e., the length between the two front ends of the shaft portion, is formed to be smaller than the length from the first conical surface 53c2 of the first bearing hole 53c1 (i.e., the bottom of the first bearing hole 53c1) to the second conical surface 54a1 of the second bearing hole 54a (i.e., the bottom of the second bearing hole 54a). Therefore, as... Figure 3 As shown in (A), a gap S in the axial direction L is provided between the front end of the first shaft portion 55b and the first conical surface 53c2. This gap S is used to prevent the first shaft portion 55b and the second shaft portion 55c from being pressed along the axial direction L by the bottom of the first bearing hole 53c1 and the second bearing hole 54a when the cylindrical shell 50, which abuts against the inner surface of the bottom wall of the bearing component 53, is fixed to the upper cover 25 on which the guide component 54 is fixed, thereby allowing the external thread 55 to rotate smoothly. However, if the gap S is set too large, the amount of movement of the external thread 55 in the axial direction L will increase, which may be affected by the position of the valve core 4 or the movement of the valve core 4 may be affected by external vibration or impact. Therefore, the size of the gap S is preferably set in the range of about 0.1 mm to 0.7 mm. It should be noted that the gap S does not necessarily need to be set between the front end of the first shaft portion 55b and the first conical surface 53c2, and can also be set at... Figure 3 The front end of the second shaft portion 55c shown in (B) is between the second conical surface 54a1.

[0046] The internal threaded component 56 is configured to include: a cylindrical base end portion 56a, which is housed within the guide member 54, and whose outer peripheral wall is in sliding contact with the inner peripheral wall of the guide member 54; and two connecting arms 56b, which extend downward from the base end portion 56a along the axis L and extend into the valve chamber 2a through the aforementioned guide hole 54b. The base end portion 56a is formed so that its central axis is coaxial with the central axis of the guide member 54. An internal thread portion 56a1 is formed at the center of the internal threaded component 56 along the axis L. This internal thread portion 56a1 is configured to engage with the external thread portion 55d. According to this structure, the internal threaded component 56 can move forward and backward coaxially with the central axis in the axis L direction as the external thread 55 rotates. The connecting arms 56b are used to connect the drive unit 5 to the valve core 4. Figure 2 As shown, the connecting arm 56b has an arc-shaped curved plate portion 56b1 extending along the axis L from a portion of the periphery of the base end portion 56a, and a planar portion 56b2 connecting the ends of the arc of the curved plate portion 56b1 to each other, each having a semi-circular cross-section. The planar portions 56b2 of each connecting arm 56b are radially opposed to each other at the base end portion 56a, and each has a through hole 56b3 formed at its lower end, extending in a direction intersecting the axis L. A shaft-shaped fixing pin 59 is inserted into and fixed in the through hole 56b3.

[0047] In this valve device 1, the valve core 4 slides along the axis L to switch the refrigerant flow path. First, the drive unit 5 is driven, causing the valve core 4 to slide downwards, covering the second port 32 and the outlet port 31 with the valve core body 40. Thus, the second port 32 and the outlet port 31 are connected. Additionally, the inlet port A is connected to the first port 30. At this time, high-pressure refrigerant flows into the valve chamber 2a via the inlet connecting flow path 20 and the inlet port A, and is then sent to the condenser via the first port 30 and the first connecting flow path 21. On the other hand, low-pressure refrigerant from the evaporator flows into the bowl-shaped recess 40c via the second port 32 and the second connecting flow path 23, and is then sent to the compressor suction port via the outlet port 31 and the outlet connecting flow path 22. Next, the valve core 4 is slid upwards, covering the outlet port 31 and the first port 30 with the valve core body 40. Thus, the outlet port 31 and the first port 30 are connected. Additionally, the inlet port A is connected to the second port 32. At this time, high-pressure refrigerant flows into the valve chamber through inlet connection flow path 20 and inlet port A, and is then sent to the evaporator through second port 32 and second connection flow path 23. On the other hand, low-pressure refrigerant from the condenser flows into the bowl-shaped recess 40c through first port 30 and first connection flow path 21, and is then transported to the compressor suction port through outlet port 31 and outlet connection flow path 22.

[0048] According to the above embodiments, the valve device 1 includes: a hollow cylindrical valve body 2; a valve seat 3 disposed on the valve body 2 and having valve ports 30, 31, and 32; a valve core 4 slidably disposed inside the valve body 2 along the axis L; and a drive unit 5 that slides and drives the valve core 4. The drive unit 5 includes: a stepper motor 5a (motor unit) having a rotatable magnetic rotor 51 (rotor); a bottomed cylindrical shell 50 (housing) fixed to the valve body 2 and housing the magnetic rotor 51; an external thread 55 fixed to the magnetic rotor 51 and extending along the axis L; and an internal thread component 56 threadedly engaged with the external thread 55 and capable of rotating along the axis L with the rotation of the external thread 55. The internal thread component 56 is guided forward and backward by a guide component 54, which is configured to not move relative to the cylindrical shell 50; and a bearing component 53, which is disposed inside the bottom side of the cylindrical shell 50 and provides rotatable support for the external thread 55. A cylindrical first shaft portion 55b and a second shaft portion 55c (shaft portion) are respectively provided at both ends of the external thread 55. A first bearing hole 53c1 and a second bearing hole 54a (bottomed concave hole) are respectively provided on the guide component 54 and the bearing component 53 at the core position of the external thread 55. The first shaft portion 55b is inserted into the first bearing hole 53c1 and the second shaft portion 55c is inserted into the second bearing hole 54a, thereby providing rotatable support for the external thread 55.

[0049] According to this invention, cylindrical first shaft portion 55b and second shaft portion 55c are respectively provided at both ends of the external thread 55 fixed to the magnet rotor 51 and extending along the axis L. Furthermore, the first shaft portion 55b is inserted into a first bearing hole 53c1 coaxially arranged with the axis L, and the second shaft portion 55c is inserted into a second bearing hole 54a coaxially arranged with the axis L. Thus, the external thread 55 is rotatably supported coaxially with the axis L. In this way, by rotatably supporting the external thread 55, it is possible to prevent the first shaft portion 55b from tilting towards the first bearing hole 53c1 or the second shaft portion 55c from tilting towards the second bearing hole 54a, thereby reducing the frictional resistance between each shaft portion 55b, 55c and each bearing hole 53c1, 54a, and rotatably supporting the external thread 55 and the magnet rotor 51. Furthermore, by reducing the frictional resistance when the magnet rotor 51 rotates, the attenuation of the stepper motor 5a's output can be suppressed, thus obtaining a valve device 1 that improves the driving efficiency of the valve core 4. Furthermore, according to this structure, the external thread 55, which engages with the internal thread component 56 that moves along the axis L, is supported by the bearing component 53 and the guide component 54, and its movement in the direction intersecting the axis L is restricted. Therefore, even if an external impact or vibration is applied, the vibration of the external thread 55, the internal thread component 56, and the valve core 4 can be suppressed, and the impact on the operation of the valve core 4 caused by the contact between the magnet rotor 51 and the cylindrical shell 50 can be reduced. In addition, the movement of the external thread 55 in the direction of the axis L can be restricted by the bottom of the first bearing hole 53c1 and the bottom of the second bearing hole 54a.

[0050] Furthermore, according to the structure of this embodiment, at least three radially protruding protrusions 53a1 are provided on the outer periphery of the bearing component 53. These protrusions 53a1 are configured to abut against the inner surface of the cylindrical shell 50. Therefore, when the bearing component 53 is inserted into the cylindrical shell 50, insertion is achieved by contacting the protrusions 53a1 rather than the entire circumference of the bearing component 53. This allows the bearing component 53 to be inserted into the cylindrical shell 50 with a low load and ensures concentricity between the cylindrical shell 50 and the bearing component 53. Additionally, the inner diameters of the first bearing hole 53c1 and the second bearing hole 54a are larger than the outer diameters of the first shaft portion 55b and the second shaft portion 55c. A conical first conical surface 53c2 is formed at the bottom of the first shaft portion 55b, and a conical second conical surface 54a1 is formed at the bottom of the second shaft portion 55c. Therefore, the first shaft portion 55b and the second shaft portion 55c are concentric by the respective conical surfaces 53c2 and 54a1. In addition, by making the inner diameter of the first shaft portion 55b and the second shaft portion 55c larger than the outer diameter of the first shaft portion 55b and the second shaft portion 55c, the external thread 55 can rotate more smoothly, and the frictional resistance of the first shaft portion 55b and the second shaft portion 55c in the first bearing hole 53c1 and the second bearing hole 54a can be suppressed.

[0051] Furthermore, according to the structure of this embodiment, the length between the two front ends of the first shaft portion 55b and the second shaft portion 55c, i.e., the length between the two front ends of the shaft portion, is set to be smaller than the length from the first conical surface 53c2 (bottom of the first bearing hole 53c1) of the first bearing hole 53c1 to the second conical surface 54a1 (bottom of the second bearing hole 54a) of the second bearing hole 54a. A gap S is provided between the front end of the first shaft portion 55b and the bottom of the first conical surface 53c2. Therefore, it is possible to prevent the first shaft portion 55b and the second shaft portion 55c from being pressed along the axis L by the bottom of the first bearing hole 53c1 and the second bearing hole 54a, and the external thread 55 can rotate smoothly. In addition, according to the structure of this embodiment, the guide member 54 supports the internal thread member 56 so that it cannot rotate around the axis L but can move forward and backward along the axis L. Therefore, the guide member 54, the internal thread member 56, and the external thread 55 can be used to form a direct-acting mechanism 5b that converts the rotational motion of the magnet rotor 51 into motion in the axis L direction.

[0052] Furthermore, the present invention is not limited to the above-described embodiments, and includes other structures that can achieve the purpose of the present invention. The following variations are also included in the present invention. Figure 6 This is a cross-sectional view of the external thread 55 and the bearing component 53 in the first modified example. The shape of the front end of the first shaft portion 55b1 in this first modified example differs from that of the first shaft portion 55b in the above embodiment, as it is bent upwards. Furthermore, unlike the above embodiment, in this first modified example, the upper end of the first minor diameter portion 53b of the bearing component 53 does not abut against the inner surface of the bottom wall of the cylindrical shell 50 when the bearing component 53 is inserted into the cylindrical shell 50. That is, when the bearing component 53 is inserted into the cylindrical shell 50, a gap in the axial direction L is formed between the upper end of the first minor diameter portion 53b and the inner surface of the bottom wall of the cylindrical shell 50. A compression spring A (force-applying component) is disposed on the outer periphery of the first minor diameter portion 53b.

[0053] One end of the compression spring A along its axis L abuts against the inner surface of the bottom wall of the cylindrical shell 50, while the other end along its axis L abuts against the upper wall of the large-diameter portion 53a, situated between the cylindrical shell 50 and the bearing component 53, applying force to the bearing component 53 downwards, i.e., towards the guide component 54. According to this structure, by applying force to the bearing component 53 and the external thread 55 towards the guide component 54 using the compression spring A, the bearing component 53, the first shaft portion 55b, and the second shaft portion 55c are pressed towards the guide component 54, thus shortening the length from the first conical surface 53c2 of the first bearing hole 53c1 to the second conical surface 54a1 of the second bearing hole 54a. This eliminates the aforementioned gap S. Therefore, looseness can be eliminated between the first bearing hole 53c1 and the second bearing hole 54a and the first shaft portion 55b1 and the second shaft portion 55c. In addition, the force applied by the compression spring A is preferably set to a load such that the bearing component 53, external thread 55, internal thread component 56, and valve core 4, which are movable parts, will not vibrate due to external vibrations.

[0054] Figure 7 This is an enlarged cross-sectional view of the external thread 55 and the guide member 54 in the second modification. In this second modification, a spherical member B, made of metal and shaped like a ball, is welded to the front end of the second shaft portion 55c1. That is, a spherical surface is provided at the front end of the second shaft portion 55c1. According to this structure, the external thread 55 can contact the bottom of the second bearing hole 54a via the spherical surface provided at the front end of the second shaft portion 55c1, thereby reducing the contact area with the bottom of the second bearing hole 54a, thereby enabling the external thread 55 to rotate smoothly with low torque.

[0055] Furthermore, in the above embodiment, the gap S is provided between the front end of the first shaft portion 55b and the first conical surface 53c2, and between the second shaft portion 55c and the second conical surface 54a1. However, it is not limited to this, and the gap S may be provided between the front end of the first shaft portion 55b and the first conical surface 53c2, and between the second shaft portion 55c and the second conical surface 54a1. In addition, in this embodiment, the front ends of the first shaft portion 55b and the second shaft portion 55c are formed in a planar shape. In the first variation, the front end of the first shaft portion 55b is curved in a way that protrudes upward. In the second variation, a spherical component B made of metal is welded to the front end of the second shaft portion 55c1. However, the shapes of the first shaft portion 55b and the second shaft portion 55c are not limited to the various embodiments and modifications. They may be bent in a way that does not protrude upward as a whole, as in the first modification, but rather the outer diameter portion may be chamfered. They may also be conical shapes with an acute angle to the cone angle of the first cone surface 53c2 and the second cone surface 54a1. Any of these shapes or combinations thereof may be used in the above embodiments and modifications.

[0056] Furthermore, in the first modified example, the compression spring A is configured to be sandwiched between the cylindrical shell 50 and the bearing component 53 to apply force to the bearing component 53 toward the guide component 54. However, it is not necessary to use the compression spring A. Any force-applying component that can apply force to the bearing component 53 toward the guide component 54, such as a disc spring or a cylindrical elastic component made of rubber, is acceptable.

[0057] Furthermore, in the above-described embodiments, the first modification, and the second modification, the cylindrical shell 50, which is formed as a bottomed cylindrical shell, is fixed at its front end to the upper edge of the small-diameter portion 25a of the upper cover 25 by welding or the like, and is then fixed to the valve body 2 via the upper cover 25. However, the structure for fixing the cylindrical shell 50 is not limited to this. For example, the outer diameter of the retaining ring 57 of the guide member 54 may be set to be approximately the same as the outer diameter of the small-diameter portion 25a of the upper cover 25, and the retaining ring 57 may be fixed to the upper cover 25 by welding or the like while the retaining ring 57 is connected to the cylindrical shell 50. Alternatively, the cylindrical shell 50 may be directly fixed to the valve body 2 by forming the valve body 2, the lower cover 24, and the upper cover 25 as a single unit, and fixing the cylindrical shell 50 as the valve body 2. In this invention, "fixed to valve body 2" in "bottomed cylindrical shell 50 (housing) with built-in magnet rotor 51 (rotor) fixed to valve body 2" has two meanings: that is, it is directly fixed to valve body 2, or fixed to valve body 2 via other components (top cover 25, retaining ring 57, etc.), or it can include any structure as described above, that is, maintaining concentricity between valve body 2, bearing component 53 and guide component 54 which is configured not to move relative to cylindrical shell 50, and maintaining the clearance size between the two ends of bearing component 53 and guide component 54 and external thread 55, so that they are connected relative to valve body 2 without relative displacement.

[0058] Furthermore, in the valve device 1 of this embodiment, the valve core 4 is formed as a bowl-shaped recess 40c with an elongated oval shape in the direction of the axis L. The opening edge 40a of the bowl-shaped recess 40c is a sealing part S, which can slide in contact with the sealing surface 33 of the valve seat part 3. The valve seat part 3 is provided with a plurality of valve ports 30, 31, and 32 that open on the sealing surface 33. The valve device 1 has been described as an example of a sliding switching valve that switches the flow path of the refrigerant in a refrigeration cycle, etc., but the valve device 1 is not limited to this sliding switching valve. For example, the present invention can also be applied to a sliding switching valve with multiple valve cores 4, where the valve seat part 3 has three or more ports. In addition, the present invention can also be applied to an electric valve in which the valve core 4 does not have a bowl-shaped recess 40c, does not switch between connecting and disconnecting multiple ports, and has a valve seat part 3 that opens in the direction of the axis L, which slides freely into or out of the valve body 2 in the direction of the axis L. Similarly, the present invention can also be applied to an electric valve with a needle-shaped valve core 4 that does not have a bowl-shaped recess 40c, does not switch between connecting and disconnecting multiple ports, and has a valve seat 3 with a port opening in the direction of axis L that can slide freely close or separate in the direction of axis L inside the valve body 2 to adjust the opening of the port.

[0059] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments, and design changes that do not depart from the spirit of the present invention are also included in the present invention.

Claims

1. A valve device comprising: a hollow cylindrical valve body; a valve seat disposed on the valve body and having a valve port; a valve core slidably disposed inside the valve body along an axial direction; and a drive unit for slidingly driving the valve core. The valve device is characterized in that... The drive unit has: The motor section has a rotor capable of rotation; A bottomed cylindrical housing is fixed to the valve body and houses the rotor. External thread, which is fixed to the rotor and extends in the axial direction; An internally threaded component that can move forward and backward in the axial direction as the external thread rotates; A guide member configured to be immobile relative to the housing and to guide the internally threaded component forward and backward; and A bearing component is disposed inside the bottom side of the housing and provides rotational support for the external thread. Cylindrical shaft portions are provided at both ends of the external thread. A recessed hole is formed at the center of the bearing component, which serves as the core of the external thread. This recessed hole is a bottomed recessed hole that opens downwards and is configured to allow insertion of one end of the external thread into the shaft portion. Similarly, a recessed hole is formed at the center of the guide component, which is a bottomed cylindrical component, which also serves as the core of the external thread. This recessed hole opens upwards and is configured to allow insertion of the other end of the external thread into the shaft portion. These recessed holes are located on the inner surface of the bottom of the guide component on the valve port side, thereby supporting the external thread so that it can rotate about an axis. The internal thread component has a cylindrical base end, on the inside of which an internal thread is formed that engages with the external thread. The outer surface of the base end is guided forward and backward by the inner surface of the guiding member.

2. The valve device according to claim 1, characterized in that, At least three radially protruding protrusions are provided on the outer periphery of the bearing component, the protrusions being able to abut against the inner surface of the housing.

3. The valve device according to claim 1, characterized in that, The inner diameter of the recess is larger than the outer diameter of the shaft, and a conical surface is formed at the bottom of the recess.

4. The valve device according to claim 1, characterized in that, A spherical surface is provided at the front end of the shaft portion at at least one of the two ends of the external thread.

5. The valve device according to claim 1, characterized in that, The length between the two front ends of the shaft portion of the external thread is less than the length from the bottom of one of the recesses to the bottom of the other recess, and a gap is provided between the front end of at least one of the shaft portions and the bottom of the recess.

6. The valve device according to claim 1, characterized in that, A force-applying component is provided between the bottom of the housing and the bearing component, which applies force to the bearing component toward the guide component.

7. The valve device according to claim 1, characterized in that, The guide component supports the internally threaded component so that it cannot rotate about the axis.

8. The valve device according to any one of claims 1 to 7, characterized in that, The valve core is formed as a bowl-shaped recess with an elongated oval shape in the axial direction. The opening edge of the bowl-shaped recess becomes a sealing part, which can slide in contact with the sealing surface of the valve seat. The valve seat is provided with a plurality of valve ports that open on the sealing surface.

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