Electronic expansion valve

Abstract

The present invention provides an electronic expansion valve (100) comprising a fixed seat assembly (10), a transmission assembly (20), and a valve core assembly (30), wherein the fixed seat assembly (10) has a valve chamber (11) and a valve port (12), and the transmission assembly (20) includes a screw (21) and a nut (22), the screw (21) being circumferentially rotatable, and the nut (22) being screwed onto the screw (21) and engaged with the fixed seat assembly (10) in a position restricted along its own circumferential direction. The valve core assembly (30) is located within the valve chamber (11) and includes a valve core body (31) and an elastic member (33). The valve core body (31) is provided with a housing groove (311), the elastic member (33) is fitted into the housing groove, and the nut (22) fits into the housing groove (311) and is pressed against the elastic member (33).

Claims

1. A fixed seat assembly having a valve chamber and a valve port, A transmission assembly comprising a screw and a nut, wherein the screw is axially engaged with the fixed seat assembly, the screw is circumferentially rotatable about its axis, the nut is fitted onto the outer circumference of the screw, the nut screws into the screw, and the outer wall of the nut is circumferentially engaged with the fixed seat assembly, An electronic expansion valve comprising a valve core assembly located within the valve chamber, the valve core assembly comprising a valve core body and an elastic member, the valve core body being provided with a housing groove, the elastic member being fitted into the housing groove, and the nut being fitted into the housing groove and pressed against the elastic member, The electronic expansion valve is characterized in that the nut can push the valve core body toward the valve opening via the elastic member, thereby closing the valve opening with the valve core body.

2. The valve core assembly further includes a retaining block, the opening of the housing groove is positioned away from the valve opening, the retaining block is located within the housing groove, and the retaining block is fixedly connected to the opening of the housing groove. The electronic expansion valve according to claim 1, wherein the nut is provided with a position-restricting projection, the position-restricting projection is located at the end of the nut adjacent to the valve opening, one end of the position-restricting projection is used to press against the elastic member, and the other end of the position-restricting projection is used to abut against the retaining block.

3. The electronic expansion valve according to claim 2, wherein the valve core assembly further includes a transmission block, the transmission block being locked between the position-regulating projection and the elastic member.

4. An electronic expansion valve according to claim 3, wherein a stopper surface is formed in the housing groove, the stopper surface is positioned away from the valve opening, the elastic member is located on the side of the stopper surface closest to the valve opening, and at least a portion of the elastic member is positioned protruding from the stopper surface, and an assembly gap can be formed between the transmission block and the stopper surface.

5. The fixed seat assembly includes a connecting sleeve and a guide sleeve, the guide sleeve being fitted onto the outer circumference of the connecting sleeve and welded to the guide sleeve, the guide sleeve being positioned close to the valve opening side of the connecting sleeve, the screw being positioned and engaged with the inner wall of the connecting sleeve along its axial direction, and the outer wall of the nut being positioned and engaged with the inner wall of the connecting sleeve along its circumferential direction, the electronic expansion valve according to claim 1.

6. An electronic expansion valve according to claim 5, wherein a position-restricting surface is formed on the inner wall of the guide sleeve, and when the valve core body moves away from the valve opening, the valve core body can be locked to the position-restricting surface, a position-restricting ring is provided on the valve core body, the position-restricting ring is positioned close to the position-restricting surface, the position-restricting ring is used to contact the position-restricting surface, and the thickness of the position-restricting ring is h, where h ≤ 1.5 mm.

7. The fixed seat assembly includes a connecting sleeve and a guide sleeve, the connecting sleeve and the guide sleeve are fitted together and connected, and the valve chamber is drilled in the guide sleeve. The connecting sleeve is provided with a first wall, the first wall is positioned in close contact with the guide sleeve, and a welding gap is formed between the first wall and the guide sleeve. At the end of the first wall away from the valve opening, a welding groove is formed between the connecting sleeve and the guide sleeve, and the welding groove communicates with the welding gap. The electronic expansion valve according to claim 1, wherein a second passage is formed between the connecting sleeve and the guide sleeve at the end of the first wall adjacent to the valve opening, and the second passage connects the valve chamber and the weld gap.

8. The fixed seat assembly further includes a valve seat and an inlet pipe, wherein the valve seat is fitted onto the outer wall of the guide sleeve, and the valve chamber is enclosed and formed between the valve seat and the guide sleeve, and the inlet pipe is inserted into the side wall of the valve seat and communicates with the valve chamber. The guide sleeve includes a guide segment and a connecting segment, the guide segment is positioned close to the connecting sleeve relative to the connecting segment, the guide segment is gap-fitted to the inner wall of the valve seat, the outer diameter of the guide segment tends to increase along the direction from the connecting sleeve toward the valve chamber, and the connecting segment is interference-fitted to the inner wall of the valve seat. The electronic expansion valve according to claim 7, wherein the inlet pipe, the valve seat, the connecting sleeve and the guide sleeve are integrally welded by furnace welding.

9. The electronic expansion valve according to claim 1, wherein the transmission assembly further includes a rotor and a connecting plate, the connecting plate being fixedly connected to the rotor, the connecting plate having a mounting hole, the screw being inserted into the mounting hole, and the screw being interference-fitted to the inner wall of the mounting hole, and the rotor being rotated by driving the screw via the connecting plate.

10. The outer peripheral wall of the valve core body is sealed and movably engaged with the inner peripheral wall of the valve chamber, the valve core body partitions the valve chamber into an upper chamber and a lower chamber, the lower chamber is used to connect the inlet pipe and the valve opening, the valve core body has an upper end surface and a lower end surface, the upper end surface is positioned facing the upper chamber, the lower end surface is positioned facing the valve opening, and the valve core body is provided with a first passage that penetrates the lower end surface and the upper end surface. The lower end surface is used to close the valve opening, and when the lower end surface closes the valve opening, the valve opening communicates with the upper chamber via the first passage, as described in claim 1.

11. An annular mounting portion is formed within the first passage, a position-restricting projection is provided at the end of the transmission assembly, the position-restricting projection is mounted within the annular mounting portion, both ends of the position-restricting projection along its axial direction abut against two opposing side walls of the annular mounting portion, a communication passage is formed between the outer circumferential wall of the position-restricting projection and the inner wall of the annular mounting portion, and the communication passage communicates with the first passage, as described in claim 10.

12. A notch is provided on the outer circumference of the position-regulating projection, the notch extends through both ends of the position-regulating projection along the axial direction of the position-regulating projection, and the communication passage is formed by being surrounded by the notch and the inner circumferential wall of the annular mounting portion. The electronic expansion valve according to claim 11, wherein the notch is positioned so as to be offset from the upper edge of the annular mounting portion along the radial direction of the annular mounting portion, and the notch is positioned so as to be offset from the lower edge of the annular mounting portion along the radial direction of the annular mounting portion, thereby connecting the communication passage to the first passage.

13. The electronic expansion valve further includes a retaining block and a transmission block, the retaining block and the transmission block are each connected to the inner wall of the first passage, the retaining block and the transmission block are spaced apart along the axis of the first passage, and the annular mounting portion is formed by being surrounded by the transmission block, the inner wall of the first passage and the retaining block. The electronic expansion valve according to claim 12, wherein the retaining block is positioned close to the upper end surface, a flow gap is formed between the inner circumferential wall of the retaining block and the outer circumferential wall of the transmission assembly with a gap between them, and the lower end surface communicates with the upper end surface via the first passage, the communication passage and the flow gap.

14. The electronic expansion valve according to claim 13, further comprising an outer shell, the outer shell covering the side of the fixed seat assembly away from the valve opening, the outer shell and the fixed seat assembly enclosing a rotor chamber, a through hole provided in the side wall of the fixed seat assembly, the through hole communicating the upper chamber and the rotor chamber.

15. The fixed seat assembly includes a connecting sleeve and a guide sleeve, the connecting sleeve being used to mount the transmission assembly, and the valve chamber and the through hole being drilled in the guide sleeve, The electronic expansion valve according to claim 14, wherein the connecting sleeve is provided with a first wall and a second wall, the first wall is welded to the guide sleeve, the second wall is positioned at a distance from the guide sleeve, and a second passage is formed between the second wall and the guide sleeve, the second passage connecting the upper chamber and the through hole.

16. The outer circumferential wall of the nut includes a cylindrical surface and a projection, the projection protruding outward along the radial direction of the cylindrical surface, the fixed seat assembly has a mounting channel, the inner wall of the mounting channel includes a centering surface and a position-regulating surface, the centering surface is in close contact with the cylindrical surface, and the position-regulating surface is in close contact with the projection, The electronic expansion valve according to claim 1, wherein the nut is movable relative to the fixed seat assembly along its axial direction, and the position restricting surface engages with the projection to restrict the circumferential rotation of the nut.

17. The electronic expansion valve according to claim 16, wherein the shape of the inner wall of the mounting channel is the same as the shape of the outer wall of the nut, and the outer wall of the nut is provided in close contact with the inner wall of the mounting channel.

18. The electronic expansion valve according to claim 16, wherein the number of protrusions is multiple, and the multiple protrusions are distributed at intervals along the circumferential direction of the nut.

19. The aforementioned projection is configured in an elongated shape, and the projection extends along the axial direction of the nut. Furthermore, the position regulating structure for an electronic expansion valve according to claim 16, wherein the cross-sectional width of the projection tends to decrease along the direction from the axis of the nut toward the cylindrical surface.

20. The connecting sleeve includes a position-retaining segment and a housing segment, wherein the inner diameter of the position-retaining segment is smaller than the inner diameter of the housing segment, the outer wall of the nut is positioned in close contact with the inner wall of the position-retaining segment, the nut is slidable along the inner wall of the position-retaining segment, and the outer wall of the nut is positioned at a distance from the inner wall of the housing segment. The electronic expansion valve according to claim 16, wherein the position regulating segment is provided with a relief groove, the relief groove is located at the axial end of the position regulating segment itself, and the relief groove has a shape that extends outward with respect to the axis of the position regulating segment.

21. The electronic expansion valve further includes a bearing, the fixed seat assembly is provided with an assembly hole, the bearing is mounted in the assembly hole, and the screw is inserted into the bearing. The electronic expansion valve according to claim 1, wherein the inner ring of the bearing is clearance-fitted onto the screw, or the outer ring of the bearing is clearance-fitted onto the inner wall of the assembly hole, or the inner ring of the bearing is clearance-fitted onto the screw and the outer ring of the bearing is clearance-fitted onto the inner wall of the assembly hole.

22. The electronic expansion valve according to claim 21, wherein a first position-restricting step and a second position-restricting step are formed on the outer circumference of the screw, the first position-restricting step and the second position-restricting step are spaced apart along the axial direction of the screw, the first position-restricting step is used to lock one end of the bearing, the second position-restricting step is used to lock the other end of the bearing, and at least one of the first position-restricting step and the second position-restricting step is detachably connected to the screw.

23. The electronic expansion valve according to claim 22, further comprising an elastic support member, one end of the elastic support member connected to the first position regulating step, and the other end of the elastic support member connected to the side of the bearing away from the second position regulating step.

24. The electronic expansion valve according to claim 22, wherein a mounting groove is formed in the assembly hole, the bearing is mounted in the mounting groove, and one end of the bearing in its axial direction abuts against one side of the mounting groove, and the other end of the bearing in its axial direction abuts against the other side of the mounting groove.

25. The electronic expansion valve according to claim 21, wherein the screw is fixedly connected to the inner ring of the bearing, and the outer ring of the bearing is clearance-fitted with the inner wall of the assembly hole.

26. The electronic expansion valve according to claim 1, further comprising a position regulating ring and a snap ring, wherein the outer circumferential wall of the screw is provided with an engagement groove, the position regulating ring is fitted onto the outer circumference of the screw, the position regulating ring is provided with an assembly groove corresponding to the engagement groove, the assembly groove has an opening, an assembly gap is formed between the opening and the screw, at least a portion of the snap ring is housed in the engagement groove, the other portion of the snap ring is housed in the assembly groove, and when the end of the position regulating ring away from the assembly groove is subjected to an acting force along the axis of the screw in the direction of the opening, the inner wall of the assembly groove can cooperate with the inner wall of the engagement groove to firmly grip the snap ring, the width of the assembly gap is L, the diameter of the snap ring is D, and D > L.

27. The electronic expansion valve according to claim 26, wherein a guide slope is provided on the outer wall of the screw, the guide slope is located on one side of the engagement groove, and the distance from the guide slope to the axis of the screw tends to increase along the direction from the guide slope toward the engagement groove.

28. The assembly groove is provided with a contact slope, which is used to contact the snap ring. The electronic expansion valve according to claim 27, wherein the contact slope is positioned facing the opening, and the distance from the contact slope to the axis of the position regulating ring tends to increase along the direction from the bottom of the assembly groove to the opening.

Images