Electric valve

Abstract

To provide an electric valve that allows for proper assembly of parts. [Solution] The electric valve comprises a retaining cylinder fixed to a valve body unit and slidably housing a valve body, an annular sealing unit that seals the space between the valve body and the retaining cylinder, and a retaining member that attaches the sealing unit to the valve body. The retaining member has a large-diameter cylindrical portion and a small-diameter column portion smaller in diameter than the large-diameter cylindrical portion. The valve body has a valve body end that abuts against the small-diameter column portion. A circumferential groove is formed by a first stepped portion adjacent to the small-diameter column portion of the large-diameter cylindrical portion, a first outer peripheral surface of the small-diameter column portion, a second outer peripheral surface of the valve body end, and a second stepped portion adjacent to the second outer peripheral surface of the valve body, thereby holding the sealing unit. The sealing unit has an O-ring in contact with the bottom surface of the circumferential groove and a sliding ring disposed between the O-ring and the inner circumferential surface of the retaining cylinder.

Description

Technical Field

[0001] The present invention relates to an electric valve.

Background Art

[0002] Conventionally, an electric valve is assembled, for example, in the middle of a fluid piping system and used to open and close a fluid flow path or control the flow rate (see, for example, Patent Document 1). In such an electric valve, a valve body is driven by a drive source such as a stepping motor mounted on the valve body to achieve accurate flow rate control.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electric valve of Patent Document 1, an annular pressing member and a valve body are arranged inside a cylindrical holding member. A circumferential groove is formed by the pressing member and the small-diameter upper end portion of the valve body, and an O-ring is mounted in the circumferential groove to seal between the valve body and the valve body guide hole.

[0005] Here, as the valve body opens and closes, the valve body guide hole and the O-ring slide relative to each other. Therefore, in order to protect the O-ring, a cylindrical sliding member may be fitted on the outer side in the radial direction thereof. In such a case, if the O-ring and the sliding member are integrally incorporated into the small-diameter upper end portion of the valve body, the O-ring may be turned up or biased inside the sliding member due to the friction between the O-ring and the outer peripheral surface of the upper end small-diameter portion, thereby causing torsion of the sliding member and possibly preventing proper sealing.

[0006] This invention has been made in view of the above problems, and aims to provide an electric valve that allows for proper assembly of parts. [Means for solving the problem]

[0007] The electric valve of the present invention is Valve body and, A valve body unit having a valve seat and a valve chamber formed therein, A can joined to the valve body unit, A rotor disposed inside the aforementioned can, A thrust transmission member connected to the valve body and moving axially in accordance with the rotation of the rotor, A retaining cylinder is provided to slidably house the valve body and is fixed to the valve body unit, An annular sealing unit that seals the space between the valve body and the retaining cylinder, The seal unit has a retaining member for attaching it to the valve body, The aforementioned retaining member has a large-diameter cylindrical portion and a small-diameter cylindrical portion having a smaller diameter than the large-diameter cylindrical portion. The valve body has a valve body end that abuts against the small diameter column portion, A circumferential groove for holding the seal unit is formed by a first stepped portion adjacent to the small-diameter column portion of the large-diameter cylindrical portion, a first outer peripheral surface of the small-diameter column portion, a second outer peripheral surface of the valve body end, and a second stepped portion adjacent to the second outer peripheral surface of the valve body. The seal unit is characterized by having an O-ring in contact with the bottom surface of the circumferential groove and a sliding ring disposed between the O-ring and the inner circumferential surface of the retaining cylinder. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an electric valve that allows for proper assembly of components. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a longitudinal cross-sectional view showing the open state of an electric valve according to the first embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view showing an enlarged view of the area near the upper end of the valve body in Figure 1. [Figure 3] Figure 3 shows the process of assembling the O-ring and sliding ring into the retaining member and valve body. [Figure 4] Figure 4 is a longitudinal cross-sectional view similar to Figure 2, showing an electric valve according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the electric valve according to the present invention will be described with reference to the drawings. In this specification, unless otherwise specified, the upper part of the drawings will be considered the upper direction in the direction of gravity (hereinafter simply referred to as "upper"), and the lower part of the drawings will be considered the lower direction in the direction of gravity (hereinafter simply referred to as "lower"). In this specification, the flow direction described is such that the inlet side connected to the side of the valve chamber in the valve body is the upstream side, and the outlet pipe side connected to the lower part of the valve chamber is the downstream side. However, it goes without saying that the electric valve of the present invention can also be used for applications where the flow is in the reverse direction.

[0011] [First Embodiment] Figure 1 is a longitudinal cross-sectional view showing the open state of the electric valve 1 according to the first embodiment of the present invention. Figure 2 is a cross-sectional view showing an enlarged view of the area near the upper end of the valve body 20 in Figure 1. The electric valve 1 of this embodiment is used, for example, to adjust the refrigerant flow rate in a refrigeration cycle. Let L be the axis of the electric valve 1.

[0012] The electric valve 1 mainly comprises a valve body 5 having a cylindrical metal body 6 such as stainless steel, a can 58 fixed to the valve body 5, a support member 19 fixedly positioned on the valve body 5 in the internal space defined by the valve body 5 and the can 58, a valve element 20 supported by the support member 19 and positioned to move up and down in the internal space, and a rotor 57 mounted above the valve body 5 to move the valve element 20 up and down. The rotor 57, when combined with a stator (not shown) positioned outside the can 58, constitutes a stepping motor.

[0013] In the cylindrical body 6, a valve chamber VC is defined inside, and a horizontal first opening 6a that opens to the valve chamber VC is formed on its side portion, and a vertical second opening 6b that opens to the valve chamber VC is formed at its bottom. A valve seat member 8 having a shape formed by coaxially connecting a small-diameter cylinder and a large-diameter cylinder with substantially equal wall thicknesses is attached to the second opening 6b. The valve seat member 8 has a valve seat 8a at its upper end and a fitting portion 8c at its lower end, and the fitting portion 8c is fitted into the second opening 6b. Further, the valve seat member 8 has a valve port 9 that opens to the valve chamber VC and a connection port 12 that is connected to the valve port 9 and has a larger diameter than the valve port 9 and opens to the outside, with the central axis being the axis L. The valve seat member 8 and the valve body 5 including the cylindrical body 6 to which the valve seat member 8 is connected constitute a valve body unit.

[0014] The end of the inflow pipe IT is inserted into the first opening 6a and joined by brazing, and the end of the outflow pipe OT is inserted into the connection port 12 and joined by brazing.

[0015] Also, an inclined surface 8b that is connected to the valve seat 8a is formed at the upper end portion of the valve seat member 8, and the upper end portion of this inclined surface 8b is located below the axis O of the inflow pipe IT.

[0016] A cylindrical base 13 having a shape formed by coaxially connecting a small-diameter cylinder and a large-diameter cylinder is attached to the open upper end of the cylindrical body 6. The lower end portion of a capped cylindrical can 58 is joined to the upper end portion of the cylindrical base 13 by welding or the like.

[0017] A support member 19 is disposed inside the cylindrical base 13 and the can 58. The support member 19 has a holding cylinder 14 and a bearing member 15. The holding cylinder 14 is formed by coaxially connecting a thin-walled cylindrical circular tube portion 14e and a partition wall 14c that extends radially inward from the inner circumference of the circular tube portion 14e. The hollow bearing member 15 has a shape formed by coaxially connecting an enlarged-diameter cylindrical portion 15b and a reduced-diameter cylindrical portion 15a disposed below it, and has an internal thread 15i on the inner circumference of the reduced-diameter cylindrical portion 15a.

[0018] While making the outer peripheral step portion abut against the inner peripheral step portion of the cylindrical base portion 13, the holding cylinder 14 is fixed to the cylindrical base portion 13 by press-fitting or the like and is positioned in the axial direction. Further, a bearing member 15 is inserted into the inner periphery on the upper end side of the holding cylinder 14, and the upper end of the holding cylinder 14 is caulked, whereby the holding cylinder 14 and the bearing member 15 are connected and fixed.

[0019] A spring chamber SC is defined between the partition wall 14c of the holding cylinder 14 and the bearing member 15, and an opening spring 25 that biases the valve body 20 in the valve opening direction is housed in the spring chamber SC.

[0020] The upper portion of the valve body 20 is slidably inserted into a valve body guide hole 14b formed below the partition wall 14c in the holding cylinder 14. In the valve body 20, a large-diameter passage portion 32b that opens in a tapered shape toward the valve port 9 of the valve seat member 8 at the lower end and a small-diameter passage portion (second through hole) 32c that is connected to the large-diameter passage portion 32b and opens at the upper end are formed.

[0021] The small-diameter lower portion 23c of the thrust transmission member 23 is fitted and fixed to the small-diameter passage portion 32c in a state of passing through a through hole (first through hole) 24c of a pressing member 24 described later. At the lower end portion of the valve body 20, a substantially frustum-shaped valve body portion 20a that contacts and separates from the valve seat 8a of the valve seat member 8 to open and close the valve port 9 is formed.

[0022] Here, the large-diameter passage portion 32b has a tapered shape in which the inner diameter linearly increases from the lower end of the small-diameter passage portion 32c toward the valve port 9 of the valve seat member 8 as viewed in side view. However, for example, it may have a tapered shape in which it curves toward the valve port 9 of the valve seat member 8 (for example, a curve consisting of a parabola that is convex upward or downward).

[0023] On the inner circumference of the rotor 57, a mysterious planetary gear type reduction mechanism (reduction mechanism) 40 is provided, which consists of a sun gear 41 integrally formed with the rotor support member 56, a fixed ring gear 47 fixed to the upper end of a thin-walled cylindrical body 43 fixed to the upper part of the retaining cylinder 14, planetary gears 42 positioned between the sun gear 41 and the fixed ring gear 47 and meshing with each other, a carrier 44 that rotatably supports the planetary gears 42, a bottomed ring-shaped output gear 45 that meshes with the planetary gears 42 from the outside, and an output shaft 46 whose upper part is fixed by press-fitting or the like in a hole formed in the bottom of the output gear 45. Here, the number of teeth of the fixed ring gear 47 is set to be different from the number of teeth of the output gear 45. The mysterious planetary gear type reduction mechanism 40 and a stepping motor constitute the drive mechanism.

[0024] A hole is formed in the center of the upper part of the output shaft 46, and the lower part of the support shaft 49, which passes through the center of the sun gear 41 (rotor support member 56) and the carrier 44, is inserted through this hole. The upper part of this support shaft 49 has an outer diameter that is approximately the same as the inner diameter of the can 58, and is inserted through the central hole of the support member 48, which is positioned in contact with the can 58 above the rotor support member 56. The rotor 57 itself is held in place by the support member 48 and the like so as not to move up and down inside the can 58, and the positional relationship with the stator, which is fitted and fixed to the can 58, is always maintained constant.

[0025] The lower part of the output shaft 46 of the reduction mechanism 40 is rotatably fitted into the upper part of the bearing member 15, and a slit-shaped fitting portion 46a extending along the axis L is formed on the lower part of the output shaft 46. A plate-shaped blade portion 17c is provided protruding from the upper end of the rotary lifting shaft 17, which has a male screw 17a that screws into the female screw 15i of the bearing member 15, and the blade portion 17c is slidably fitted into the fitting portion 46a. When the output shaft 46 rotates together with the rotation of the rotor 57, and the rotational force is transmitted to the rotary lifting shaft 17, the rotary lifting shaft 17 moves up and down while rotating due to the screw-feed motion caused by the screw-feeding of the female screw 15i of the bearing member 15 and the male screw 17a of the rotary lifting shaft 17.

[0026] Below the rotary lifting shaft 17, a stepped cylindrical thrust transmission member 23 is positioned, which transmits the downward thrust of the rotary lifting shaft 17 via a ball 18 and a ball seat 16. By interposing the ball 18 between the rotary lifting shaft 17 and the thrust transmission member 23, even if the rotary lifting shaft 17 rotates while descending, only the downward thrust is transmitted from the rotary lifting shaft 17 to the thrust transmission member 23, and no rotational force is transmitted.

[0027] The thrust transmission member 23 consists of a large-diameter upper part 23a into which the ball seat 16 is fitted on its inner circumference, an intermediate body part 23b that is slidably inserted into a hole formed in the partition wall 14c of the retaining cylinder 14, and a small-diameter lower part 23c which is smaller in diameter than the intermediate body part 23b, arranged in series from above. Inside the thrust transmission member 23, there is a through hole 32d with axis L as the central axis, and a lateral hole 32e perpendicular to the through hole 32d that communicates with the back pressure chamber BC (described later). However, the upper end opening of the through hole 32d is closed by the ball seat 16. The through hole 32d and the lateral hole 32e constitute a through hole. Furthermore, the through hole 32d, the lateral hole 32e, and the large-diameter passage part 32b and small-diameter passage part 32c of the valve body 20 constitute a pressure equalization passage AP that connects the back pressure chamber BC and the discharge passage (outlet pipe OT).

[0028] As described above, the small-diameter lower portion 23c of the thrust transmission member 23 is fitted and fixed into the narrow-diameter passage portion 32c of the valve body 20 by press-fitting or the like, and the valve body 20 and the thrust transmission member 23 can move up and down together as a single unit. An annular retaining member 24 is sandwiched and fixed between the upper end surface of the valve body 20 and the lower end step portion of the intermediate body portion 23b of the thrust transmission member 23.

[0029] In Figure 2, the retaining member 24 consists of a large-diameter cylindrical portion 24a and a small-diameter cylindrical portion (also called a small-diameter column) 24b, which has a smaller diameter than the large-diameter cylindrical portion 24a, connected coaxially with respect to the axis L, and has a through hole 24c in the center. The valve body 20 has an upper small-diameter portion (also called the valve body end) 20b facing the small-diameter cylindrical portion 24b. The outer diameter of the upper small-diameter portion 20b, which is coaxial with the axis L, is approximately equal to the outer diameter of the small-diameter cylindrical portion 24b. Also, the outer diameter of the valve body 20 inside the retaining cylinder 14, excluding the upper small-diameter portion 20b, is approximately equal to the outer diameter of the large-diameter cylindrical portion 24a. The valve body 20 has a stepped surface 20c (second stepped portion) connecting the small-diameter cylindrical portion 24b and the outer circumferential surface other than the small-diameter cylindrical portion 24b. The stepped surface 20c is parallel to the lower surface 24d of the large-diameter cylindrical portion 24a.

[0030] By press-fitting the small-diameter lower portion 23c, which has a through hole 24c through it, into the small-diameter passage portion 32c, the retaining member 24 and the valve body 20 are connected and fixed together, with the lower surface of the small-diameter cylindrical portion 24b and the upper surface of the upper small-diameter portion 20b in contact. The small-diameter lower portion 23c may also be in an interlocking relationship with respect to the through hole 24c.

[0031] By connecting and fixing the retaining member 24 and the valve body 20, a circumferential groove CG is formed by the lower surface (first step portion) 24d of the large-diameter cylindrical portion 24a adjacent to the small-diameter cylindrical portion 24b, the outer circumferential surface of the small-diameter cylindrical portion 24b (also called the first outer circumferential surface), the outer circumferential surface of the upper small-diameter portion 20b (also called the second outer circumferential surface), and the step portion 20c adjacent to the upper small-diameter portion 20b. That is, the bottom surface of the circumferential groove CG is composed of the outer circumferential surface of the small-diameter cylindrical portion 24b and the outer circumferential surface of the upper small-diameter portion 20b, and the opposing sides of the circumferential groove CG are composed of the lower surface 24d of the large-diameter cylindrical portion 24a and the step portion 20c.

[0032] Within the circumferential groove CG, an O-ring 61 is arranged in contact with the outer circumferential surface of the small-diameter cylindrical portion 24b and the outer circumferential surface of the upper small-diameter portion 20b, and a cylindrical sliding ring 62 (seal ring, or lip seal) is arranged. The sliding ring 62 is made of a resin material that has high sliding properties and is resistant to wear, and has a wall thickness that is approximately equal in the circumferential cross-section. The O-ring 61 and the sliding ring 62 constitute an annular seal unit.

[0033] The sliding ring 62 has an outer cylindrical surface 62a, an upper tapered surface 62b extending upward from the upper end of the outer cylindrical surface 62a while decreasing in diameter, and a lower tapered surface 62c extending downward from the lower end of the outer cylindrical surface 62a while decreasing in diameter. The sliding ring 62 also has a retaining groove 62d on its inner circumference for holding the O-ring 61.

[0034] With the O-ring 61 held in the retaining groove 62d, the sliding ring 62 and the O-ring 61 are incorporated into the circumferential groove CG and inserted into the valve body guide hole 14b of the retaining cylinder 14, allowing the outer cylindrical surface 62a to slide against the inner circumferential surface of the valve body guide hole 14b.

[0035] Figure 3 shows the process of assembling the O-ring 61 and the sliding ring 62 into the retaining member 24 and the valve body 20. Here, the axial length of the small diameter cylindrical portion 24b is a, and the axial length of the upper small diameter portion 20b is also a.

[0036] As shown in Figure 3(a), the O-ring 61 and the sliding ring 62 are combined and placed on the upper small-diameter portion 20b of the valve body 20. In the free state (when no external force is applied), the inner diameter of the O-ring 61 is smaller than the outer diameter of the upper small-diameter portion 20b, so the O-ring 61 remains placed on the upper small-diameter portion 20b.

[0037] In this state, when the retaining member 24 is brought closer from above, the lower end of the small-diameter cylindrical portion 24b comes into contact with the inner diameter side of the O-ring 61, as shown in Figure 3(b). If the retaining member 24 is then pushed towards the valve body 20, the O-ring 61 and the sliding ring 62 are elastically deformed to expand in diameter as they are pressed evenly from both sides by the retaining member 24 and the valve body 20. Furthermore, as shown in Figure 3(c), the O-ring 61 rides onto the outer circumferential surface of the upper small-diameter portion 20b and the outer circumferential surface of the small-diameter cylindrical portion 24b, allowing the O-ring 61 and the sliding ring 62 to be assembled into the circumferential groove CG. After the O-ring 61 and the sliding ring 62 are assembled into the retaining member 24 and the valve body 20, the small-diameter lower portion 23c of the thrust transmission member 23, which is inserted into the retaining cylinder 14, can be press-fitted into the through hole 24c of the retaining member 24 and the narrow-diameter passage portion 32c of the valve body 20 (Figure 2). This prevents the retaining member 24 from separating from the valve body 20. Note that either the upper small-diameter portion 20b or the small-diameter cylindrical portion 24b may be pressed into the O-ring 61 first.

[0038] Subsequently, the valve body 20, which incorporates the O-ring 61, sliding ring 62, and retaining member 24, is inserted into the retaining cylinder 14, the upper surface of the large-diameter cylindrical portion 24a is brought into contact with the lower surface of the partition wall 14c, the small-diameter lower portion 23c of the thrust transmission member 23 is inserted through the central hole of the partition wall 14c, and then press-fitted into the through hole 24c of the retaining member 24 and the narrow-diameter passage portion 32c of the valve body 20. However, it is also possible to first assemble the small-diameter lower portion 23c of the thrust transmission member 23 into the retaining cylinder 14, then insert the valve body 20, which incorporates the O-ring 61, sliding ring 62, and retaining member 24, into the retaining cylinder 14, and press-fit the small-diameter lower portion 23c protruding from the central hole of the partition wall 14c into the through hole 24c and the narrow-diameter passage portion 32c.

[0039] If the retaining member 24 is a perfect annular shape (consisting only of a large-diameter cylindrical portion) and the axial length of the small-diameter cylindrical portion 24b is (2·a) (as shown by a dashed line in Figure 2), then in order to fit the O-ring 61 and the sliding ring 62 into the circumferential groove, they must be moved along the small-diameter cylindrical portion 24b over a relatively long distance. In such a case, during long movement, the O-ring 61 may bend up due to friction with the outer surface of the small-diameter cylindrical portion 24b (the entire inner circumference being displaced towards the outer circumference), or become misaligned, which may cause twisting of the sliding ring 62.

[0040] In contrast, according to this embodiment, when the O-ring 61 rides onto the outer circumferential surfaces of the upper small-diameter portion 20b and the small-diameter cylindrical portion 24b, which have the same axial length a, it receives equal frictional forces in opposite directions from both outer circumferential surfaces, thus suppressing problems such as curling up or becoming uneven. As a result, the position of the sliding ring 62 that holds the O-ring 61 is stable, and the entire outer cylindrical surface 62a can be brought into close contact with the valve body guide hole 14b. Note that the axial lengths of the upper small-diameter portion 20b and the small-diameter cylindrical portion 24b do not always have to be the same. For example, when the total length is (2·a), the axial length of one of the upper small-diameter portion 20b and the small-diameter cylindrical portion 24b may be arbitrarily set to (0.7·a) or more and (1.3·a) or less.

[0041] In Figure 1, as described above, a valve opening spring 25 made of a compression coil spring is positioned in the spring chamber SC above the partition wall 14c of the retaining cylinder 14, with its lower end supported by the partition wall 14c. A spring support body 28 having flange-shaped hooks 28a and 28b on the upper and lower sides is arranged around the upper end of the thrust transmission member 23. The upper hook 28a of the spring support body 28 rests on the upper part of the valve opening spring 25, and the lower hook 28b is hooked onto the lower end step of the large-diameter upper part 23a of the thrust transmission member 23, thereby enabling the biasing force (lifting force) of the valve opening spring 25 to be transmitted to the valve body 20 via the thrust transmission member 23.

[0042] Furthermore, the retaining cylinder 14 has a communication hole 14d that connects the spring chamber SC and the inside of the can 58, canceling out the differential pressure between them.

[0043] (Operation of the electric valve) When the rotor 57 of the stepping motor is driven to rotate in one direction from the state shown in Figure 1, the rotation of the rotor 57 is reduced and transmitted to the rotary lifting shaft 17 via the output shaft 46 of the reduction mechanism 40. The rotary lifting shaft 17 rotates and descends due to the screw-feeding motion caused by the threading of the female thread 15i of the bearing member 15 and the male thread 17a of the rotary lifting shaft 17. The thrust of this rotary lifting shaft 17 pushes down the thrust transmission member 23 and the valve body 20 against the biasing force of the valve opening spring 25, and finally the valve body portion 20a, which is the lower end of the valve body 20, seats on the valve seat 8a and the valve opening 9 is closed. As a result, the refrigerant that has flowed from the inlet pipe IT into the valve chamber VC is prevented from flowing to the outlet pipe OT side.

[0044] In contrast, when the rotor 57 of the stepping motor is driven to rotate in the opposite direction, the rotation of the rotor 57 is transmitted to the rotary lifting shaft 17 at a reduced speed via the output shaft 46 of the reduction mechanism 40, and the rotary lifting shaft 17 rotates and rises due to the screw-feeding motion caused by the screwing of the female screw 15i and the male screw 17a. Accordingly, the thrust transmission member 23 and the valve body 20 are lifted by the biasing force of the valve opening spring 25, and the valve body 20a separates from the valve seat 8a and the valve port 9 opens. As a result, the refrigerant that has flowed from the inlet pipe IT into the valve chamber VC is allowed to flow through the valve port 9 to the outlet pipe OT side.

[0045] In this embodiment, a back pressure chamber BC is defined above the valve body 20 between the retaining member 24 and the partition wall 14c of the retaining cylinder 14. Furthermore, the narrow-diameter passage portion 32c communicates with the back pressure chamber BC via the through hole 32d and the lateral hole 32e of the thrust transmission member 23. For this reason, in order to balance the downward force (force acting in the closing direction) acting on the valve body 20 in the closed state with the upward force (force acting in the opening direction) acting on the valve body 20 (cancel the differential pressure), the diameter of the back pressure chamber BC and the diameter of the valve port 9 are set to be approximately the same. To ensure this cancellation function, it is important to seal the space between the valve body guide hole 14b and the valve body 20 with the O-ring 61 and the sliding ring 62 to prevent the movement of refrigerant from the valve chamber VC to the back pressure chamber BC. Since the sliding ring 62 is provided with an upper tapered surface 62b and a lower tapered surface 62c, when the outer cylindrical surface 62a slides against the inner circumferential surface of the valve body guide hole 14b, smooth sliding without any catching is ensured regardless of whether the sliding is in the up or down direction.

[0046] Furthermore, since the O-ring 61 is positioned across the contact surface between the lower surface of the retaining member 24 and the upper end small diameter portion 20b of the valve body 20, refrigerant does not pass through.

[0047] [Second Embodiment] Figure 4 is a longitudinal cross-sectional view similar to Figure 2, showing an electric valve according to a second embodiment of the present invention. In this embodiment, only the retaining member 24A and the valve body 20A differ from the first embodiment; the other components are the same as in the first embodiment, so a redundant explanation is omitted.

[0048] The valve body 20A differs from the first embodiment only in its upper tapered portion 20Ab; the rest of its configuration is the same as the first embodiment, so a redundant explanation will be omitted. The upper tapered portion 20Ab has a tapered outer surface that becomes smaller in diameter as it approaches the top.

[0049] The retaining member 24A is formed by coaxially connecting a large-diameter cylindrical portion 24a and a small-diameter tapered portion (also called a small-diameter column) 24Ab, the tapered portion having a maximum diameter smaller than that of the large-diameter cylindrical portion, and has a through hole 24c in the center. The small-diameter tapered portion 24Ab has a tapered outer surface that becomes smaller in diameter as it extends downwards. Preferably, the taper apex angle (the angle between a pair of outer surfaces that straddle the axis L in a side view) of the small-diameter tapered portion 24Ab and the upper end tapered portion 20Ab are the same, and it is also preferable that their axial lengths are equal. That is, it is preferable that the small-diameter tapered portion 24Ab and the upper end tapered portion 20Ab have a common frustoconical shape.

[0050] According to this embodiment, by connecting and fixing the retaining member 24A and the valve body 20A, a circumferential groove CGA is formed to hold the O-ring 61 and the sliding ring 62 by the lower surface 24d of the large-diameter cylindrical portion 24a, the tapered outer surface (also called the first outer surface) of the small-diameter tapered portion 24Ab, the tapered outer surface (also called the second outer surface) of the upper end tapered portion 20Ab, and the stepped surface 20c.

[0051] Since the outer circumferential surfaces of the upper tapered portion 20Ab and the small-diameter tapered portion 24Ab have opposing tapered shapes, when the O-ring 61 rides onto both outer circumferential surfaces during assembly, it receives a lower and more even frictional force, further suppressing problems such as the O-ring 61 curling up or becoming uneven. As a result, the position of the sliding ring 62 that holds the O-ring 61 is stable, and the entire outer cylindrical surface 62a can be brought into close contact with the valve body guide hole 14b.

[0052] It should be noted that the present invention is not limited to the embodiments described above. Within the scope of the present invention, any component of the embodiments described above can be modified. Furthermore, any component can be added to or omitted in the embodiments described above. In addition, it is of course possible to use the refrigerant even in a reverse flow state, in which case the refrigerant flows from the outlet pipe OT into the valve chamber and flows out from the inlet pipe IT.

[0053] This specification includes disclosures of the following inventions. (First aspect) Valve body and, A valve body unit having a valve seat and a valve chamber formed therein, A can joined to the valve body unit, A rotor disposed inside the aforementioned can, A thrust transmission member connected to the valve body and moving axially in accordance with the rotation of the rotor, A retaining cylinder is provided to slidably house the valve body and is fixed to the valve body unit, An annular sealing unit that seals the space between the valve body and the retaining cylinder, The seal unit has a retaining member for attaching it to the valve body, The aforementioned retaining member has a large-diameter cylindrical portion and a small-diameter cylindrical portion having a smaller diameter than the large-diameter cylindrical portion. The valve body has a valve body end that abuts against the small diameter column portion, A circumferential groove for holding the seal unit is formed by a first stepped portion adjacent to the small-diameter column portion of the large-diameter cylindrical portion, a first outer peripheral surface of the small-diameter column portion, a second outer peripheral surface of the valve body end, and a second stepped portion adjacent to the second outer peripheral surface of the valve body. The seal unit has an O-ring that contacts the bottom surface of the circumferential groove and a sliding ring disposed between the O-ring and the inner circumferential surface of the retaining cylinder. An electric valve characterized by the following features.

[0054] (Second aspect) The small-diameter column portion and the valve body end portion have a cylindrical shape coaxial with the axis of the electric valve and have the same outer diameter. An electric valve according to a first embodiment, characterized by the following:

[0055] (Third aspect) The small-diameter column portion has a tapered shape that decreases in diameter towards the valve body end, and the valve body end has a tapered shape that decreases in diameter towards the small-diameter column portion. An electric valve according to a first embodiment, characterized by the following:

[0056] (Fourth aspect) The aforementioned small-diameter column section and the aforementioned small-diameter column section have a common frustoconical shape. A third embodiment of an electric valve characterized by the following:

[0057] (Fifth aspect) The axial length of the small-diameter column portion and the axial length of the valve body end are approximately equal. An electric valve according to any of the first to fourth embodiments, characterized by the above.

[0058] (Sixth aspect) The retaining member has a first through hole, the valve body has a second through hole, and a part of the thrust transmission member penetrates the first through hole and is fitted into the second through hole by press-fitting. An electric valve according to any of the first to fifth embodiments, characterized by the above.

[0059] (Seventh aspect) A back pressure chamber is formed by the retaining cylinder and the valve body inserted into the retaining cylinder, and the back pressure chamber communicates with a discharge passage through a through hole formed in a part of the thrust transmission member. An electric valve according to any of the first to sixth embodiments, characterized by the above. [Explanation of symbols]

[0060] 1. Electric valve 5 Valve body 8 Valve seat member 8a Valve seat 9 valve openings 14 Holding tube 20, 20A valve body 20b Upper end small diameter section 20Ab upper tapered section 20c step surface 23. Thrust transmission member 24,24A Retaining member 24a Large diameter cylindrical section 24b Small diameter cylindrical section 24c through hole 24d Lower surface of the large diameter cylindrical section 32c Narrow diameter passage section 40 Mysterious Planetary Gear Reduction Mechanism 57 Rotor 58 Can 61 O-rings 62 Sliding ring AP pressure equalization passage BC back pressure chamber CG,CGA circumferential groove L axis SC spring chamber VC valve chamber IT inflow pipe OT outflow pipe

Claims

1. Valve body and, A valve body unit having a valve seat and a valve chamber formed therein, A can joined to the valve body unit, A rotor disposed inside the aforementioned can, A thrust transmission member connected to the valve body and moving axially in accordance with the rotation of the rotor, A retaining cylinder is provided to slidably house the valve body and is fixed to the valve body unit, An annular sealing unit that seals the space between the valve body and the retaining cylinder, The seal unit has a retaining member for attaching it to the valve body, The aforementioned retaining member has a large-diameter cylindrical portion and a small-diameter cylindrical portion having a smaller diameter than the large-diameter cylindrical portion. The valve body has a valve body end that abuts against the small diameter column portion, A circumferential groove for holding the seal unit is formed by a first stepped portion adjacent to the small-diameter column portion of the large-diameter cylindrical portion, a first outer peripheral surface of the small-diameter column portion, a second outer peripheral surface of the valve body end, and a second stepped portion adjacent to the second outer peripheral surface of the valve body. The seal unit has an O-ring that contacts the bottom surface of the circumferential groove and a sliding ring disposed between the O-ring and the inner circumferential surface of the retaining cylinder. An electric valve characterized by the following features.

2. The small-diameter column portion and the valve body end portion have a cylindrical shape coaxial with the axis of the electric valve and have the same outer diameter. The electric valve according to feature 1.

3. The small-diameter column portion has a tapered shape that decreases in diameter towards the valve body end, and the valve body end has a tapered shape that decreases in diameter towards the small-diameter column portion. The electric valve according to feature 1.

4. The aforementioned small-diameter column section and the aforementioned small-diameter column section have a common frustoconical shape. The electric valve according to feature 3.

5. The axial length of the small-diameter column portion and the axial length of the valve body end are approximately equal. The electric valve according to feature 1.

6. The retaining member has a first through hole, the valve body has a second through hole, and a part of the thrust transmission member penetrates the first through hole and is fitted into the second through hole by press-fitting. The electric valve according to feature 1.

7. A back pressure chamber is formed by the retaining cylinder and the valve body inserted into the retaining cylinder, and the back pressure chamber communicates with a discharge passage through a through hole formed in a part of the thrust transmission member. The electric valve according to any one of claims 1 to 6.

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