DEVICE FOR CONTROLLING A FLOW RATE AND EXPANDING A FLUID IN A FLUID CIRCUIT AND METHOD FOR OPERATING THE DEVICE

Abstract

A device for controlling a flow rate and expanding a fluid in a fluid circuit. The device is formed with an enclosure and a valve element arranged inside the enclosure. The valve element which is arranged movably in a linear movement in the direction of a longitudinal axis relative to the enclosure has a sealing surface and a control area formed at a first end face of the valve element and arranged adjacent to the sealing surface in the axial direction. The sealing surface is formed as a lateral surface of a straight circular cylinder with a constant outer diameter. An outer diameter of a surface of the control area corresponds to the outer diameter of the sealing surface. The control area has throughflow apertures and at least one control aperture. The valve element in the control area is formed with a substantially hollow circular cylindrical-shaped wall.

Claims

1-26. (canceled)

27. A device for controlling a flow rate and expanding a fluid in a fluid circuit, comprising: an enclosure; and a valve element arranged in an interior of the enclosure, which is arranged moveably in a linear movement in a direction of a longitudinal axis relative to the enclosure, wherein the valve element has a sealing surface and a control area that is formed at a first end face of the valve element and arranged adjacent to the sealing surface in an axial direction, wherein: the sealing surface has a shape of a lateral surface of a straight circular cylinder with a constant outer diameter and an outer diameter of a surface of the control area corresponds to an outer diameter of the sealing surface, and the control area has throughflow apertures and at least one control aperture, the valve element in the control area being formed with a substantially hollow circular cylindrical-shaped wall.

28. The device according to claim 27, wherein the throughflow apertures each have a shape of a cut which, starting from the first end face of the valve element, is formed extending in the axial direction into the wall of the valve element.

29. The device according to claim 27, wherein the at least one control aperture has a shape of a cut which, starting from the first end face of the valve element, is formed extending in the axial direction into the wall of the valve element.

30. The device according to claim 28, wherein in each case side walls of the cut formed in the axial direction and in pairs are oriented parallel to one another.

31. The device according to claim 30, wherein the side walls of the cuts are arranged equally spaced from one another in each case.

32. The device according to claim 28, wherein the throughflow apertures each have a same extension in the direction of the longitudinal axis of the device.

33. The device according to claim 29, wherein the at least one control aperture has a larger extension in the direction of the longitudinal axis of the device than the throughflow apertures.

34. The device according to claim 29, wherein the at least one control aperture in a longitudinal extension has a first section and a second section, wherein the at least one control aperture in the first section is formed with a fully perforated wall of the valve element and in the second section with a steadily increasing wall thickness of the wall of the valve element and a groove base.

35. The device according to claim 34, wherein a shape of the first section of the at least one control aperture substantially corresponds to a shape of one of the throughflow apertures.

36. The device according to claim 34, wherein the second section of the at least one control aperture has a free cross-section that tapers in a direction of the sealing surface, wherein the wall thickness of the wall of the valve element increases continuously from zero to a maximum wall thickness at a transition to the sealing surface.

37. The device according to claim 27, wherein the valve element has an aperture which is formed as a through hole and arranged concentrically extending in the direction of the longitudinal axis.

38. The device according to claim 27, wherein an actuator and a transmission assembly and a sliding rotary lock assembly are formed for transmitting a rotational movement of the actuator into the linear movement.

39. The device according to claim 38, wherein the actuator is formed as a drive shaft oriented in the axial direction.

40. The device according to claim 39, wherein the drive shaft is formed to be connected to an electric motor.

41. The device according to claim 39, wherein the transmission assembly is formed as mating threads between the drive shaft and the valve element, wherein the drive shaft is arranged inserted into an aperture of the valve element.

42. The device according to claim 41, wherein a male thread is formed on an outer side of the drive shaft and a female thread is formed within the aperture of the valve element.

43. The device according to claim 41, wherein the transmission assembly is formed with a free cross-section between the drive shaft and the valve element.

44. The device according to claim 38, wherein the valve element has formations which are formed as first components of the sliding rotary lock assembly at a second end face oriented towards the actuator and in pairs opposite one another protruding from the valve element in an orthogonal direction to the longitudinal axis.

45. The device according to claim 44, wherein the enclosure in an area of the formations of the valve element is formed with recesses as second components of the sliding rotary lock assembly arranged opposite one another with respect to the longitudinal axis of the valve element, each of which corresponds in shape to one of the formations of the valve element.

46. The device according to claim 27, wherein the valve element is arranged within a valve seat element.

47. The device according to claim 46, wherein the valve element is arranged sealingly via at least two sealing elements to the enclosure and to the valve seat element.

48. The device according to claim 47, wherein a first one of the sealing elements is formed as a sliding seal.

49. The device according to claim 48, wherein a second one of the sealing element is formed as a sliding seal.

50. The device according to claim 49, wherein the valve element, in a closed state of the device, is arranged with the sealing surface abutting the first one of the sealing elements and the second one of the sealing elements, and that the valve element, in an open state of the device, is arranged with the sealing surface abutting the first one of the sealing elements and with the surface of the control area abutting the second one of the sealing elements.

51. A method for operating the device for controlling the flow rate and expanding the fluid in a fluid circuit according to claim 27, comprising the following steps: setting an actuator in a rotational movement about the longitudinal axis, transmitting the rotational movement of the actuator by means of a transmission assembly and a sliding rotary lock assembly into the linear movement of the valve element in the direction of the longitudinal axis relative to the enclosure, so that the valve element is moved linearly along the longitudinal axis, wherein: the device is opened or closed depending on a direction of rotation of the actuator, the valve element is always guided within two sealing elements, the valve element is always abutting a first one of the sealing elements with the sealing surface, and, depending on a position, abutting a second one of the sealing elements with the sealing surface or the surface of the control area, and a degree of opening of the device, depending on an assembly of the control area of the valve element is set with the throughflow apertures extending in the direction of the longitudinal axis and the at least one control aperture within the second one of the sealing elements.

52. Use of the device for controlling the flow rate and expanding the fluid according to claim 27 in a coolant circuit of an air conditioning system of a motor vehicle.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0063] Further details, features and advantages of configurations of the invention emerge from the following description of exemplary embodiments with reference to the associated drawings.

[0064] FIGS. 1A and 1B: show a device for controlling a flow rate and expanding a coolant with an electric drive,

[0065] FIG. 1C: shows the valve element 6′ as an individual component of the valve 1′ in a perspective view,

[0066] FIG. 1D: shows a detailed view of the valve element 6′ from FIG. 1C in a side view,

[0067] FIGS. 1E and 1F: each show a detailed view of the assembly of the valve element 6′ within the valve seat element 7′ or within the second sealing element 12′, wherein FIG. 1E shows the closed state of the device 1′ and FIG. 1F shows the valve element 6′ in the open state of the device 1′,

[0068] FIGS. 2A to 2C: show a device for controlling a flow rate and expanding a fluid in a fluid circuit, in particular a coolant circuit of an air conditioning system of a motor vehicle, with an enclosure and valve element arranged within the enclosure, as well as an actuator with a transmission assembly in the closed and open state and a control position, each in a lateral sectional illustration,

[0069] FIGS. 3A and 3B: show an assembly of the valve element within the enclosure with a sliding rotary lock assembly for transmitting a rotational movement of the actuator into a linear movement of the valve element along the axis of rotation, in a sectional illustration of a plane through the axis of rotation and a sectional illustration perpendicular to the axis of rotation,

[0070] FIGS. 4A and 4B: show the valve element as an individual component, and in a detailed view of an end face with a control aperture and throughflow apertures, each in a perspective view, and

[0071] FIG. 4C: shows a detailed view of the assembly of the valve element inside the enclosure or the valve seat element, in particular, a second sealing element.

DESCRIPTION OF AN EMBODIMENT

[0072] FIGS. 2A to 2C each show a device 1 for controlling a flow rate and expansion of a fluid in a fluid circuit, in particular a valve 1, especially in a coolant circuit of an air conditioning system of a motor vehicle, with an enclosure 2 and a valve element 6 arranged in the interior of the enclosure 2, as well as an actuator 4 with a transmission assembly 5 in a closed as well as an open state and a control state of the device 1, each shown in a lateral sectional illustration. The device 1, in particular a valve, is driven via an electric motor 3. With the electric motor 3, a drive shaft formed as an actuator 4 is set in a rotational movement 4a.

[0073] By means of the transmission assembly 5, which is formed in particular as a thread, specifically as a movement thread, on the drive shaft 4, which is oriented in the axial direction, in conjunction with a sliding rotary lock assembly 8, the rotational movement 4a of the drive shaft 4 about its longitudinal axis is transmitted into a translatory stroke movement of the valve element 6 which is preferably formed as a valve needle and thus a linear movement 6a in the axial direction or in the direction of the longitudinal axis of the drive shaft 4.

[0074] The mating threads of the transmission assembly 5 are provided between the drive shaft 4 and the valve element 6. The drive shaft 4, which substantially has the shape of a cylindrical rod, in particular a round rod with sections of different diameters, is inserted with a free end in an aperture 6b formed in the valve element 6 as a first component of the transmission assembly 5. The free end of the drive shaft 4, which is also referred to as the end section of the drive shaft 4 and is formed as a second component of the transmission assembly 5, is arranged distally to an end of the drive shaft 4 connected to the electric motor 3. The aperture 6b provided within the valve element 6 is formed as a through hole which extends along the axis of rotation or the longitudinal axis of the valve element 6. Consequently, the drive shaft 4 at the free end has a male thread as a first element of the mating threads, while a female thread is formed as a second element of the mating threads inside the aperture 6b of the valve element 6.

[0075] In the area sliding along inside the enclosure 2, the valve element 6 has formations 6c, which are formed on an end of the valve element 6 oriented towards the electric motor 3 and protrude in pairs opposite to one another from the valve element 6 in an orthogonal direction to the longitudinal axis, which is particularly evident from FIGS. 3A and 3B. FIGS. 3A and 3B show an assembly of the valve element 6 within the enclosure 2 with the sliding rotary lock assembly 8 for transmitting the rotational movement 4a of the drive shaft 4 into the linear movement 6a of the valve element 6 along the axis of rotation in a sectional illustration of a plane through the axis of rotation and a sectional illustration perpendicular to the axis of rotation. According to the section of the plane through the longitudinal axis of the device 1 according to FIG. 3A, the valve element 6 has a T-shape in the cross-section.

[0076] In the area of the formations 6c of the valve element 6 the enclosure 2 is formed with notch-shaped or groove-like recesses 2a arranged opposite one another with respect to the longitudinal axis of the valve element 6, which, in each case, correspond in shape to a formation 6c of the valve element 6. The shapes of the recesses 2a of the enclosure 2 each correspond to the outer shape of the formations 6c of the valve element 6 plus a play for sliding movement of the valve element 6 within the enclosure 2 in the axial direction.

[0077] By arranging the formations 6c of the cross-sectionally T-shaped valve element 6 within the notch-shaped or groove-like recesses 2a of the enclosure 2, a rotational movement of the valve element 6, driven by the actuator 4 rotating about the longitudinal axis, is prevented. The valve element 6 is thus moved by the rotational movement 4a of the actuator 4 without its own rotation about the longitudinal axis in the linear movement 6a.

[0078] According to FIGS. 2A to 2C, the valve element 6 is arranged within a valve seat element 7 which allows the linear movement 6a of the valve element 6 in the axial direction.

[0079] The device 1 is also formed with a first port 9 and a second port 10 for connecting to fluid lines. A passage aperture 9a of the first port 9 is oriented in the radial direction to the valve element 6, while a passage aperture 10a of the second port 10 is oriented in the axial direction of the valve element 6. The passage aperture 9a of the first port 9 is pressurized by coolant at a first pressure p1, so that the pressure p1 acts on the valve element 6 substantially in the radial direction. The passage aperture 10a of the second port 10 is pressurized by coolant at a second pressure p2, so that the pressure p2 acts on the valve element 6 substantially in the axial direction. All the pressurized surfaces of the valve body 6 are configured in such a way that the valve element 6 is arranged in an almost isostatic state. The pressure forces acting on the valve element 6 are in equilibrium.

[0080] Here, the transmission assembly 5 is formed with a free cross-section between the drive shaft 4 and the valve element 6. The wall surrounding the aperture 6b of the valve element 6 and the wall of the end section of the drive shaft 4 do not abut completely fluid-tight. The introduction of a section 5a formed as a flattened area within the transmission assembly 5 of the thread of actuator 4 which otherwise has a circular cross-section, according to FIGS. 3A and 3B, ensures as a throughflow aperture in combination with the aperture 6b of the valve element 6 the pressure equalization with respect to the second pressure p2 acting in the axial direction within the valve 1.

[0081] The valve element 6 is arranged sealed via two sealing elements 11, 12, in particular a first, dynamic sealing element 11 and a second, dynamic sealing element 12 to the enclosure 2 or the valve seat element 7. The sealing elements 11, 12 are formed to separate the areas within the device 1 that are pressurized at different pressure levels, in particular when the device 1 is used in a coolant circuit, a high pressure level and a low pressure level or suction pressure level.

[0082] The sealing elements 11, 12 formed within the device 1 in each case as a sliding seal, in particular a rod seal, in the form of an axial seal or an annular seal, and for internal sealing of the areas pressurized at different pressure levels, such as a high pressure side and a low pressure side of a coolant circuit, are arranged at a distance to one another in the axial direction at distal ends of the valve seat element 7. Here, the valve element 6 has a lateral surface of a straight circular cylinder with a constant outer diameter, which extends starting from the area of the formations 6c to a first end face in the direction of the passage aperture 10a of the second port 10.

[0083] Each of the first sealing element 11 and the second sealing element 12 act in the radial direction, so that on the one hand there is no need of applying an axial sealing force, as known from the prior art devices. On the other hand, the requirements for ensuring tightness in the de-energized state as well as jamming and possible leaks are eliminated.

[0084] In the area of the first end face oriented in the direction of the passage aperture 10a of the second port 10, the valve element 6 is formed with throughflow apertures 14 and at least one control aperture 15. Both the throughflow apertures 14 and the at least one control aperture 15 each have the shape of a cut which, starting from the end face of the valve element 6, extend in the axial direction into the valve element 6. The throughflow apertures 14 and the at least one control aperture 15 are oriented parallel to one another.

[0085] FIGS. 4A and 4B show the valve element 6 as an individual component and in a detailed view of the first end face with the throughflow apertures 14 and a control aperture 15, each in a perspective view, while FIG. 4C shows a detailed view of the assembly of the valve element 6 within the second sealing element 12 or a detailed view of the device 1 in the control position according to FIG. 2C.

[0086] The valve element 6 has a sealing surface 11a, which is formed in the shape of the lateral surface of a straight circular cylinder with a constant outer diameter and is arranged extending then to the area of the formations 6c of the sliding rotary lock assembly 8 of a second end face in the direction of the opposite first end face.

[0087] A control area 16 is provided in the area of the first end face of the valve element 6. The outer diameter of the surface of the control area 16 corresponds in this case to the outer diameter of the sealing surface 11a, so that the valve element 6 is formed with a diameter that is constant over the sealing surface 11a and the surface of the control area 16. In this way, the lateral surface of the valve element 1 with the sealing surface 11a and the surface of the control area 16 can be manufactured and measured with minimal effort and with very good accuracy and surface properties.

[0088] The throughflow apertures 14, which are formed as cuts in the shape of straight grooves, notches or slots, and the control aperture 15, which is also formed in the shape of a groove, a notch or a slot, are preferably provided evenly spaced and evenly distributed over the circumference on the valve element 6. Here, the side walls of each notch, which are oriented in the axial direction, are, on the one hand, in each case oriented parallel to one another and at the same distance from one another. On the other hand, the notches of the throughflow apertures 14 each have a same extension in the direction of the longitudinal axis of the device 1 and are therefore formed to be identical. The notch of the at least one control aperture 15 has a greater extension in the direction of the longitudinal axis of the device 1 than the throughflow apertures 14.

[0089] While the cut of the control aperture 15 in the area of the throughflow apertures 14, as a first section of the control aperture 15, is formed substantially like the cuts of the throughflow apertures 14 and extends in the radial direction over the entire axial extension completely through the wall of the hollow circular cylindrical-shaped valve element 6, the wall of the valve element 6 is closed in the radial direction in the second section adjoining the first section in the axial direction.

[0090] However, the at least one control aperture 15 has a free cross-section that tapers in the direction of the sealing surface 11a in the second area. The wall thickness of the wall of the hollow circular cylindrical-shaped valve element 6 increases continuously with a constant width of the control aperture 15 in the circumferential direction from zero in the area of the cut ends of the throughflow apertures 14 to the maximum wall thickness at the transition to the sealing surface 11a. The cut of the control aperture 15 is formed wedge-shaped in the second section in the axial direction. The wall of the valve element 6 is closed by a groove base 17. The inner diameter of the wall of the control area 16 of the valve element 6 is constant.

[0091] The longitudinal extension of the first section of the control aperture 15 with the fully perforated wall of the valve element 6 and the longitudinal extension of the second section of the control aperture 15 with a steadily increasing wall thickness of the wall of the valve element 6 and groove base 17 formed are identical.

[0092] Compared to conventional devices 1′, in which the flow cross-section is formed as a fully circumferential annular gap, in particular for the expanding flow of the fluid between the valve element 6′ and the second sealing element 12′ according to FIG. 1F, the flow cross-section of the device 1 is set and changed by means of the free cross-section of the control aperture 15.

[0093] In the illustration according to FIG. 4C, the device 1 is placed into a control position. The valve element 6 is arranged together with the control area 16 within the second sealing element 12. The throughflow apertures 14 are closed. The control aperture 15 is only partially covered by the second sealing element 12 and is therefore limited in the radial direction by the groove base 17 on the one hand and by the second sealing element 12 on the other. In this case, the flow cross-section for the flowing expansion of the fluid between the valve element 6 and the second sealing element 12 in the area of the control aperture 15 is open in the form of a gap 18, in particular a control gap.

[0094] The flow cross-section of the control gap 18 is varied continuously by means of the linear movement 6a of the valve element 6 relative to the second sealing element 12. With the opening of the throughflow apertures 14, on the one hand, the entire flow cross-section for the fluid is rapidly enlarged until the valve element 6 abuts the second sealing element 12 only in the area of the first end face. After the throughflow apertures 14 have been closed, on the other hand, the entire flow cross-section for the fluid is slowly reduced until the valve element 6 or the device 1 is closed and the valve element 6 with the sealing surface 11a also abuts the second sealing element 12 in a fluid-tight manner. Regardless of the position relative to the enclosure 2 or the sealing elements 11, 12 with the sealing surface 11a, the valve element 6 always abuts the first sealing element 11 in a fluid-tight manner.

[0095] The prestressed sealing elements 11, 12 require an inner and an outer guide. By means of the groove-shaped throughflow apertures 14 and control aperture 15 formed in the valve element 6, on the one hand, the maximum flow cross-section for the fluid can be released, while at the same time, on the other hand, the second sealing element 12 is guided over the wall of the valve element 6, which is formed as crosspieces between the throughflow apertures 14 or the control aperture 15.

[0096] The state of the device 1, in particular the closed state, the open state and the control state, is mainly determined by the assembly of the valve element 6 within the second sealing element 12.

[0097] While in conventional devices 1′ even small linear movements 6a of the valve element 6′ and thus small changes in the difference between the opposing diameters of the control surface 12a′ and sealing element 12′ have a major influence on the free flow cross-section for the fluid, small linear movements 6a of the valve element 6 of the device 1 result only in slight changes in the free flow cross-section through the control gap 18. The mass flow of the fluid through the device 1 can be set and metered much more finely.

[0098] The device 1 with the valve element 6 with the control aperture 15 is much easier to manufacture and measure compared to the known conical and cone-shaped design of the valve element 6′, especially since in the design of the conventional valve element 6′ the entire circumferential surface releases the flow cross-section and thus the cone shape has to have the highest accuracy in terms of the angle. In comparison, the control aperture 15 can be very well defined and measured at an axial end point via an axial starting point and a groove depth varying in the axial direction. Also, a deviation in the angle of incline of the groove base 17 in the axial direction as a tolerance has less of an effect when controlling than a deviation in the conical shape of the known valve element 6′, since the control aperture 15 is also defined by the width formed in the circumferential direction of the valve element 6. The width of the control aperture 15 has to be produced and measured very accurately.

LIST OF REFERENCE NUMERALS

[0099] 1, 1′ device, valve [0100] 2 enclosure [0101] 2a recess of the enclosure 2 [0102] 3 electric motor [0103] 4 actuator, drive shaft [0104] 4a rotational movement of the actuator 4 [0105] 5 transmission assembly [0106] 5a section [0107] 6, 6′ valve element [0108] 6a linear movement of the valve element 6, 6′ [0109] 6b aperture of the valve element 6, 6′ [0110] 6c formation of the valve element 6, 6′ [0111] 7, 7′ valve seat element [0112] 8 sliding rotary lock assembly [0113] 9 first port [0114] 9a passage aperture of the first port 9 [0115] 10 second port [0116] 10a passage aperture of the second port 10 [0117] 11, 11′ first sealing element [0118] 11a, 11a′ (first) sealing surface of the valve element 6, 6′ [0119] 12, 12′ second sealing element [0120] 12a′ control surface of the valve element 6′ [0121] 13′ transition area [0122] 13a′ second sealing surface of the valve element 6′ [0123] 13b′ sealing surface of the transition area 13′ [0124] 14 throughflow aperture of the valve element 6 [0125] 15 control aperture of the valve element 6 [0126] 16 control area [0127] 17 groove base [0128] 18 gap, control gap [0129] p1, p2 pressure [0130] α angle of the second sealing surface 13a′ of the valve element 6′ [0131] γ angle of the control surface 12a′