Flow channel switching valve

Abstract

Flow channel switching valve (1, 2) comprising a valve body (10) provided with a valve chamber (14) and a plurality of flow channels (11, 12, 13) communicating with the valve chamber (14), a valve element rotatably housed in the valve chamber (14) and switching a connection of the flow channels (11, 12, 13) in accordance with a rotational position, a valve stem (50) attached to the valve element along a rotational axis of the valve element, and an actuating unit (40) rotating the valve element via the valve stem (50), wherein the flow channel switching valve (1, 2) comprises the following: a rotary angle output shaft pressed into a mounting hole (55) provided in an end face (51b) of the valve stem (50); and a rotation angle detection unit that detects a rotation angle of the rotation angle output shaft around the axis of rotation, wherein the rotary angle output shaft has a small diameter section (64), a medium diameter section (63) and a large diameter section (62) which are connected in sequence in one direction of the axis of rotation, and in an inserted state prior to being pressed into the mounting hole (55) is rotatably supported about the axis of rotation in the mounting hole (55), and wherein the mounting hole (55) is provided with a press-fit section into which a section of the small diameter section (64), the medium diameter section (63) and the large diameter section (62) is pressed.

Description

Technical area

[0001] The present invention relates to a flow channel switching valve that switches a connection of flow channels by rotating a valve element. State of the art

[0002] An example of a conventional flow channel switching valve is disclosed in Patent Document 1. The flow channel switching valve includes a ball valve element and a valve housing. The ball valve element has an inflow path and an outflow path. The valve housing includes a valve chamber in which the ball valve element is rotatably housed, an inlet flow path communicating with the valve chamber, and a plurality of outlet flow paths communicating with the valve chamber. A valve stem is coupled to the ball valve element. The ball valve element rotates as the valve stem rotates, and thus the inlet flow path selectively communicates with one of the plurality of outlet flow paths. Other prior art related to flow channel switching valves is represented by Patent Documents 2 and 3. State of the art documentPatent document Patent Document 1: JP 2010-223418 A Patent document 2: DE 10 2011 101 074 A1 Patent document 3: US 2011 / 0 017 477 A1 Summary of the inventionProblem to be solved by the invention

[0003] In such a flow channel switching valve, the valve stem is combined with a rotation angle sensor, and the rotation position of the valve element is detected based on the output of the rotation angle sensor. However, there was a possibility that the output of the rotation angle sensor with respect to the rotation position of the valve element contained an error due to the accumulation of tolerances of the valve element, the valve stem, the rotation angle sensor, etc. Thus, there was room to improve the accuracy of the rotation position of the valve element.

[0004] Accordingly, it is an object of the present invention to provide a flow channel switching valve capable of effectively improving the accuracy of the rotational position of a valve element. Means of solving the task

[0005] To achieve the above-described object, a flow channel switching valve according to one aspect of the present invention is a flow channel switching valve including a valve body provided with a valve chamber and a plurality of flow channels communicating with the valve chamber, a valve element rotatably housed in the valve chamber and switching communication of the flow channels in accordance with a rotational position, a valve stem fixed to the valve element along a rotational axis of the valve element, and a drive unit that rotates the valve element via the valve stem. The flow channel switching valve includes a rotation angle output shaft press-fitted into a mounting hole provided in an end surface of the valve stem; and a rotation angle detection unit that detects a rotation angle of the rotation angle output shaft about the rotational axis.The angle output shaft includes a small-diameter portion, a medium-diameter portion, and a large-diameter portion connected sequentially in a direction of the rotation axis, and is supported in the mounting hole in an inserted state so as to be rotatable about the rotation axis before being press-fitted into the mounting hole. The mounting hole is provided with a press-fit portion into which a portion of the small-diameter portion, the medium-diameter portion, and the large-diameter portion is press-fitted.

[0006] According to the present invention, the angle output shaft includes the small diameter portion, the middle diameter portion, and the large diameter portion connected sequentially in the direction of the rotation axis. The angle output shaft is rotatably supported in the mounting hole around the rotation axis in the fitted state before being press-fitted into the mounting hole. The mounting hole provided in the valve stem is provided with the press-fit portion into which one of the small diameter portion, the middle diameter portion, and the large diameter portion of the angle output shaft is press-fitted. With this configuration, in the state where the angle output shaft is fitted into the mounting hole, the angle output shaft can be rotated around the rotation axis to perform positioning, and can be press-fitted and fixed after positioning.Accordingly, it is possible to further reduce the error in the output of the rotation angle detection unit due to the tolerances of the valve element, the valve stem, and the rotation angle detection unit. Thus, it is possible to effectively improve the accuracy of the rotation position of the valve element.

[0007] In the present invention, it is preferable that the valve stem is press-fitted into a through hole provided in a gear of the drive unit, and the press-fit portion is provided at a position offset from the gear in the direction of the rotation axis. With this configuration, it is possible to avoid the influence of deformation of the valve stem (mounting hole) due to press-fitting of the gear. Accordingly, it is possible to prevent the rotation angle output shaft from being press-fitted obliquely. Thus, it is possible to effectively improve the accuracy of the rotational position of the valve element.

[0008] In the present invention, it is preferable that the mounting hole has a guide portion with which at least one of the other portions of the small-diameter portion, the medium-diameter portion, and the large-diameter portion, except for the portion press-fitted into the press-fit portion, slidably contacts in an axial direction and a circumferential direction. With this configuration, the other portion comes into contact with the guide portion to guide the movement of the rotation angle output shaft. Thus, it is possible to more effectively prevent the rotation angle output shaft from being press-fitted obliquely with respect to the valve stem.

[0009] In the present invention, it is preferable that the guide portion be provided to be displaced by the gear in the direction of the rotation axis. With this configuration, it is possible to avoid the influence of deformation of the valve stem (mounting hole) due to the press-fitting of the gear. Accordingly, it is possible to further effectively prevent the rotation angle output shaft from being press-fitted obliquely.

[0010] In the present invention, it is preferable that the guide portion be provided to be displaced in the direction of the rotation axis by a bearing portion that rotatably supports the valve stem. With this configuration, it is possible to avoid the influence of deformation of the valve stem due to press-fitting of the rotation angle output shaft. Thus, it is possible to prevent the rotation of the valve stem from being hindered and ensure smooth rotation of the valve element.

[0011] In the present invention, it is preferable that the mounting hole is provided with the press-fit portion into which the medium-diameter portion is press-fitted, and two guide portions with which the small-diameter portion and the large-diameter portion slidably contact in an axial direction and a circumferential direction. With this configuration, the small-diameter portion and the large-diameter portion contact the two guide portions to guide the movement of the rotation angle output shaft. Thus, it is possible to more effectively prevent the rotation angle output shaft from being press-fitted obliquely with respect to the valve stem. Advantages of the invention

[0012] According to the present invention, it is possible to effectively improve the accuracy of the rotational position of the valve element. Short description of the drawings [ Fig. 1] Fig. 1 is a perspective view including a partial section of a flow channel switching valve according to a first embodiment of the present invention. [ Fig. 2] Fig. 2 is a sectional view along the line AA of Fig. 1. [ Fig. 3] Fig. 3 is a six-sided view of a ball valve element used in the flow channel switching valve of Fig. 1 is included. [ Fig. 4] Fig. 4 is a view for explaining a method of assembling the flow channel switching valve of Fig. 1 and illustrates a state in which a gear is to be attached after a valve stem has been attached to the valve element. [ Fig. 5] Fig. 5 is a view for explaining the method of assembling the flow channel switching valve of Fig. 1 and illustrates a state in which a potentiometer shaft is to be inserted into a mounting hole of the valve stem. [ Fig. 6] Fig. 6 is a view for explaining the method of assembling the flow channel switching valve of Fig. 1 and illustrates a state in which a potentiometer base is to be fixed to a valve body. [ Fig. 7] Fig. 7 is a view for explaining the method of assembling the flow channel switching valve of Fig. 1 and illustrates a state in which a potentiometer is to be attached to the potentiometer base. [ Fig. 8] Fig. 8 is a view for explaining the method of assembling the flow channel switching valve of Fig. 1 and illustrates a state in which the position of the potentiometer shaft is adjusted after the potentiometer has been attached to the potentiometer base. [ Fig. 9] Fig. 9 is a view for explaining the method of assembling the flow channel switching valve of Fig. 1 and illustrates a state in which the potentiometer shaft is pressed into the mounting hole of the valve stem. [ Fig. 10] Fig. 10 is a view illustrating a flow channel switching valve according to a second embodiment of the present invention. Embodiments of the Invention (First Embodiment)

[0013] A configuration of a flow channel switching valve according to a first embodiment of the present invention will be described below with reference to Fig. 1 to 3.

[0014] Fig. 1 is a perspective view including a partial section of the flow channel switching valve according to the first embodiment of the present invention.

[0015] Fig. 2 is a sectional view along the line AA of Fig. 1. Fig. 3 is a six-sided view of a ball valve element used in the flow channel switching valve of Fig. 1. In the following description, "upper, lower, left, and right" are used to indicate the relative positional relationship between respective components in each of the drawings, but they do not indicate the absolute positional relationship. In each of the drawings, a left-right direction is defined as an X-axis direction, a front-back direction is defined as a Y-axis direction, and a top-bottom direction is defined as a Z-axis direction. The X-axis, Y-axis, and Z-axis are orthogonal to each other.

[0016] As in the Fig. 1 and Fig. 2, a flow channel switching valve 1 of the present embodiment includes a valve body 10, a ball valve element 20, seat members 30, 30, seal members 31, 31, a drive unit 40, and a valve stem 50. The flow channel switching valve 1 also includes a potentiometer shaft 60 which is a rotation angle output shaft, a potentiometer base 70 which is a base body, and a potentiometer 80 which is a rotation angle detection unit.

[0017] The valve body 10 is made of synthetic resin and is formed in a shape of a substantially cubic box. A substantially L-shaped first flow channel 11 is provided in a left wall portion 10a of the valve body 10. A straight second flow channel 12 is provided in a front wall portion 10b of the valve body 10. A substantially L-shaped third flow channel 13 is provided in a right wall portion 10c of the valve body 10. The third flow channel is plane-symmetrical to the first flow channel 11. An opening 11a of the first flow channel 11, an opening 12a of the second flow channel 12, and an opening 13a of the third flow channel 13 face forward (the forward direction from the paper in Fig. 1, down in Fig. 2). The first flow channel 11, the second flow channel 12, and the third flow channel 13 communicate with a valve chamber 14 provided in the valve body 10. Two or four or more flow channels may be provided as the flow channels communicating with the valve chamber 14.

[0018] The ball valve element 20 is formed in a shape similar to a hollow sphere (spherical shape). The ball valve element 20 is made of, for example, metal or synthetic resin. The ball valve element 20 is housed in the valve chamber 14. The ball valve element 20 is rotatably supported by the seat elements 30, 30 (described later). Fig. 2, the ball valve element 20 has a first opening 21 open to the left side, a second opening 22 open to the front side, and a third opening 23 open to the right side. A switching flow path 25 connecting the first opening 21, the second opening 22, and the third opening 23 is provided within the ball valve element 20. The switching flow path 25 is formed in a substantially T-shape in a plan view. Alternatively, the ball valve element 20 may, for example, have only the first opening 21 and the second opening 22, and may be provided with a switching flow path 25 that is substantially L-shaped in a plan view and connects the first opening 21 and the second opening 22 in the Fig. 2. Although the ball valve element 20 is used as a valve element in the present embodiment, a column-shaped valve element may be used.

[0019] The switching flow path 25 is configured to switch the connection of the first flow channel 11, the second flow channel 12, and the third flow channel 13 in accordance with the rotational position. More specifically, the switching flow path 25 connects the first flow channel 11, the second flow channel 12, and the third flow channel 13 to each other when the ball valve element 20 is in the position shown in Fig. 2. The switching flow path 25 connects the first flow channel 11 and the second flow channel 12 with each other when the ball valve element 20 is in a rotational position which, in plan view, is 90 degrees clockwise relative to the rotational position shown in Fig. 2. The switching flow path 25 connects the second flow channel 12 and the third flow channel 13 to each other when the ball valve element 20 is in a rotational position which, in plan view, is 90 degrees counterclockwise relative to the rotational position shown in Fig. 2 illustrated rotation position.

[0020] In an upper portion of the ball valve element 20, a valve stem insertion hole 24 is provided, into which the valve stem 50 is inserted (described later). The valve stem insertion hole 24 is formed such that the ball valve element 20 rotates about an axis L, which is a rotation axis of the ball valve element 20, when the valve stem 50 rotates. Specifically, the valve stem insertion hole 24 is formed in the same shape as the sectional shape (cross-sectional shape) in the direction perpendicular to the axial direction of an angled column portion 52 of the valve stem 50. In the present embodiment, the valve stem insertion hole 24 is formed in a regular hexagonal shape ( Fig. 3).

[0021] The seat elements 30, 30 are made of, for example, synthetic resin such as polytetrafluoroethylene (PTFE) and are formed in a ring shape. The seat elements 30, 30 form a pair. The seat elements 30, 30 are housed in the valve chamber 14. The seat elements 30, 30 are arranged such that they face each other with a gap in the X-axis direction. The seat elements 30, 30 rotatably support the ball valve element 20 in the valve chamber 14, with the ball valve element 20 interposed therebetween.

[0022] The sealing elements 31, 31 are each, for example, an O-ring made of an elastic material such as a rubber material. The sealing element 31 is arranged such that it is sandwiched in a compressed state between one of the seat elements 30 and the left wall portion 10a of the valve body 10. The sealing element 31 is arranged such that it is sandwiched in a compressed state between the other of the seat elements 30 and the right wall portion 10c of the valve body 10. In the present embodiment, the sealing element 31 is mounted in an annular groove 30a provided in the seat element 30. A part of the sealing element 31 protrudes from the annular groove 30a. The sealing elements 31, 31 seal gaps between the valve body 10 and the ball valve element 20 together with the seat elements 30, 30.Alternatively, the sealing elements 31, 31 may be omitted and seat elements 30, 30 made of an elastic material, such as a rubber material, may be used, which also have the function of a sealing element.

[0023] The drive unit 40 includes a drive mechanism, a lower housing 43, and an upper housing (not shown). The drive mechanism comprises a combination of a motor (not shown) and a reduction gear including a gear 41. The lower housing 43 and the upper housing are made of resin, and the drive mechanism is housed therein. The upper housing is fixed to the lower housing 43 by a fastening structure such as a screw structure or a snap-fit ​​structure. The drive unit 40 rotates the ball valve element 20 about the axis L (described later) via the valve stem 50.

[0024] The lower housing 43 integrally includes a circular tubular support portion 45 at the center of a bottom wall 43a. The valve stem 50 is inserted into the support portion 45. The support portion 45 rotatably supports the valve stem 50. An inner peripheral wall portion 43b having a square tube shape is provided on the bottom wall 43a of the lower housing 43. The inner peripheral wall portion 43b is disposed inside the valve body 10 and combined with an upper end portion of the valve body 10. The inner peripheral wall portion 43b and the valve body 10 are joined (ultrasonically welded in the present embodiment). Alternatively, the lower housing 43 and the valve body 10 may be assembled together by a screw structure or the like.

[0025] The valve stem 50 is made of synthetic resin and is formed in a columnar shape extending straight as a whole. The valve stem 50 includes a circular columnar portion 51 and an angled columnar portion 52 coaxially connected to a lower end of the circular columnar portion 51. The valve stem 50 is arranged along the axis L.

[0026] The circular column portion 51 has an annular stop portion 53 provided at a lower end portion of the circular column portion 51 and projecting radially outward. The stop portion 53 is formed to have an outer diameter larger than the inner diameter of the bearing portion 45.

[0027] Furthermore, the circular column portion 51 has a groove provided in the lower end portion over the entire circumference at a position above the stopper portion 53. An annular O-ring 54 made of a rubber material or the like is fitted into the groove. The circular column portion 51 is inserted into the bearing portion 45. The circular column portion 51 is rotatably supported by the bearing portion 45. The outer diameter of the circular column portion 51 is slightly smaller than the inner diameter of the bearing portion 45. When the circular column portion 51 is inserted into the bearing portion 45, the O-ring 54 seals a gap between the valve stem 50 and the bearing portion 45. The sealing with the O-ring 54 prevents the fluid in the valve chamber 14 from leaking to the outside.

[0028] The gear 41 of the drive mechanism of the drive unit 40 is press-fitted onto an upper end portion of the circular column portion 51. Specifically, the circular column portion 51 is press-fitted into a through hole 41a provided in the center of the gear 41. A part of the circular column portion 51 protrudes from an upper surface 41b of the gear 41. Moreover, the upper end portion of the circular column portion 51 is provided with a flat portion 51a to prevent the press-fitted gear 41 from slipping. The gear 41 can be fixed to the valve stem 50 by a method other than press-fitting.

[0029] The angled column portion 52 is formed in a column shape having a regular hexagonal cross-sectional shape. The angled column portion 52 is inserted into the valve stem insertion hole 24 of the ball valve element 20 and is fixed to the ball valve element 20 along the axis L. The axis L of the ball valve element 20 serves as the rotation axis of the valve stem 50. The valve stem 50 is rotated about the axis L when the gear 41 rotates. The valve stem insertion hole 24 is formed in the same regular hexagonal shape as the cross-sectional shape of the angled column portion 52. Thus, the valve stem insertion hole 24 and the angled column portion 52 are matched to each other. The ball valve element 20 is rotated about the axis L when the valve stem 50 rotates. The angled column portion 52 is formed to have an outer diameter smaller than that of the stopper portion 53.

[0030] The angled column portion 52 may have a polygonal column shape other than the regular hexagonal shape, such as a triangular column shape or a quadrilateral column shape, or a column shape having a D-shaped section in which a part of the side surface of a circular column is formed as a plane. In this case, the valve stem insertion hole 24 is also formed in the same shape as the cross-sectional shape of the angled column portion 52.

[0031] Furthermore, a mounting hole 55 is provided in the center of an upwardly facing end surface 51b of the circular column portion 51. The mounting hole 55 has a substantially circular columnar interior space along the axis L. The mounting hole 55 has a lower mounting hole portion 56 and an upper mounting hole portion 57 coaxially connected to the upper surface of the lower mounting hole portion 56 ( Fig. 9). The lower portion 56 of the mounting hole and the upper portion 57 of the mounting hole have circular cross-sectional shapes. The mounting hole 55 is formed such that the diameter of the lower portion 56 of the mounting hole is smaller than the diameter of the upper portion 57 of the mounting hole. A stepped portion 58 is provided between the lower portion 56 of the mounting hole and the upper portion 57 of the mounting hole.

[0032] The lower portion 56 of the mounting hole is provided to be displaced by the gear 41 in the direction of the axis L. In the present embodiment, the lower portion 56 of the mounting hole is provided to be located on the radially inner side of the bearing portion 45. An upper end portion 57a ​​of the upper portion 57 of the mounting hole is located above the upper surface 41b of the gear 41. That is, the upper end portion 57a ​​is a portion provided to be displaced by the bearing portion 45 and the gear 41 in the direction of the axis L.

[0033] The upper end portion 57a ​​of the upper mounting hole portion 57 is a press-fit portion into which a large-diameter portion 62 of the potentiometer shaft 60 is press-fitted (described later). The lower mounting hole portion 56 is a guide portion with which a small-diameter portion 64 slidably contacts in the axial direction (the direction of the axis L, which is also the insertion direction of the potentiometer shaft 60 into the mounting hole 55) and the circumferential direction (the direction around the axis L).

[0034] The potentiometer shaft 60 is made of metal such as stainless steel or brass, or synthetic resin such as polyphenylene sulfide (PPS). The potentiometer shaft 60 is a separate component from the valve stem 50. The potentiometer shaft 60 is press-fitted into the mounting hole 55 of the valve stem 50. The potentiometer shaft 60 is coaxially fixed to the valve stem 50 by a press fit. The potentiometer shaft 60 includes a fitting shaft portion 61, the large-diameter portion 62, a medium-diameter portion 63, and the small-diameter portion 64 sequentially from the upper side to the lower side in the axial direction of the potentiometer shaft 60. In other words, the small-diameter portion 64, the medium-diameter portion 63, and the large-diameter portion 62 are connected sequentially in the direction of the axis L from the ball valve element 20 side to the gear 41 side.

[0035] The fitting shaft portion 61 is formed in a columnar shape (so-called D-section shape) and has a D-shaped section in which a part of the side surface of a circular column is formed as a plane. The fitting shaft portion 61 is provided at an end portion of the potentiometer shaft 60 and is fitted to a rotor 81 of the potentiometer 80 (described later). At least the distal end of the fitting shaft portion 61 protrudes from the mounting hole 55. The large-diameter portion 62 is formed in a circular columnar shape. The large-diameter portion 62 has a diameter larger than the diameter of the upper portion 57 of the mounting hole 55. The middle-diameter portion 63 is formed in a circular columnar shape.The medium-diameter portion 63 has a diameter smaller than the diameter of the large-diameter portion 62 and the diameter of the upper mounting hole portion 57, and larger than the diameter of the small-diameter portion 64. The medium-diameter portion 63 connects the large-diameter portion 62 and the small-diameter portion 64. The small-diameter portion 64 is formed in a circular columnar shape. The small-diameter portion 64 has the same diameter (including substantially the same diameter) as the diameter of the lower mounting hole portion 56 of the mounting hole 55.

[0036] The potentiometer base 70 is made of synthetic resin. The potentiometer base 70 integrally comprises a base body portion 71 and a meter mounting portion 72. The base body portion 71 is formed in a substantially flat plate shape. The base body portion 71 is fixed by screws 78, 78 to projections 43c, 43c projecting upward from the bottom wall 43a of the lower case 43. The meter mounting portion 72 includes a disc-shaped lower wall portion 72a and a peripheral wall portion 72b projecting upward from the peripheral edge of the lower wall portion 72a. A recess 72c is provided in the center of the lower wall portion 72a. The recess 72c is a portion to which the potentiometer 80 (described later) is mounted. Furthermore, a through hole 72d is provided in the recess 72c. The fitting shaft portion 61 of the potentiometer shaft 60 is guided through the through hole 72d.The diameter of the through hole 72d is larger than the diameter of the fitting shaft section 61.

[0037] The potentiometer 80 is a rotation angle sensor for detecting a rotation angle. The potentiometer 80 includes the disc-shaped rotor 81 and a meter body portion 82. The meter body portion 82 rotatably supports the rotor 81. The meter body portion 82 is a signal output unit that outputs a signal (voltage) corresponding to the rotation angle of the rotor 81. A fitting hole 81a, which has a D-like shape in plan view, is provided in the center of the rotor 81. The fitting shaft portion 61 of the potentiometer shaft 60 passes through the fitting hole 81a. The fitting shaft portion 61 is fitted into the fitting hole 81a, so that the rotor 81 rotates together with the fitting shaft portion 61. Rotation of the fitting shaft portion 61 causes the rotor 81 to rotate. Thus, the potentiometer 80 detects the angle of rotation of the potentiometer shaft 60 about the axis L.

[0038] In the flow channel switching valve 1, the rotation of the motor of the drive unit 40 is output to the valve stem 50 via the gear 41. The valve stem 50 rotates around the axis L. The ball valve element 20 rotates around the axis L as the valve stem 50 rotates and is positioned at each rotational position. Thus, the connection of the flow channels corresponding to the rotational position is achieved. In addition, the potentiometer shaft 60 rotates together with the valve stem 50 around the axis L. A signal corresponding to the rotation angle of the potentiometer shaft 60 is output from the potentiometer 80. The rotational position of the ball valve element 20 can be monitored based on the signal output from the potentiometer 80.

[0039] Next, an example of a method for assembling the flow channel switching valve 1 of the present embodiment will be described with reference to FIG. Fig. 4 to 9 described.

[0040] The Fig. 4 to 9 are views for explaining a method of assembling the flow channel switching valve of Fig. 1 and are, in order, (1) a perspective view illustrating a state in which a gear is to be attached after a valve stem has been attached to a valve element, (2) a perspective view illustrating a state in which a potentiometer shaft is to be inserted into a mounting hole of the valve stem, (3) a perspective view illustrating a state in which a potentiometer base is to be fixed to a valve body, (4) a perspective view illustrating a state in which a potentiometer is to be attached to the potentiometer base, (5) a perspective view illustrating a state in which the position of the potentiometer shaft is adjusted after the potentiometer has been attached to the potentiometer base, and (6) a sectional view illustrating a statein which the potentiometer shaft is pressed into the mounting hole of the valve stem. , Fig. 9A illustrates a state in which the potentiometer shaft has been inserted into the mounting hole of the valve stem (inserted state before press-fitting), and Fig. 9B illustrates a state in which the potentiometer shaft has been pressed into and fixed to the mounting hole of the valve stem.

[0041] First, the ball valve element 20, the seat elements 30, 30, and the seal elements 31, 31 are housed in the valve chamber 14 of the valve body 10. Then, a jig (not shown) is inserted from the second flow passage 12 to position the ball valve element 20. The angled column portion 52 of the valve stem 50 is inserted into the valve stem insertion hole 24 to fix the valve stem 50 to the ball valve element 20. In this state, the valve stem 50 is arranged along the axis L (Z-axis direction). Then, the valve body 10 and the lower housing 43 are assembled together, while the circular column portion 51 of the valve stem 50 is inserted into the bearing portion 45. Ultrasonic waves are emitted into the lower housing 43 to ultrasonically weld the lower housing 43 to the valve body 10.

[0042] Next, as in Fig. 4, the circular column portion 51 of the valve stem 50 is press-fitted into the gear 41, and other components (not shown) constituting the drive mechanism are assembled with the lower housing 43.

[0043] Next, as in Fig. 5 illustrates, the potentiometer shaft 60 is inserted into the mounting hole 55 of the valve stem 50. Specifically, the potentiometer shaft 60 is inserted into the mounting hole 55 from the small-diameter portion 64, and the medium-diameter portion 63 is inserted into the mounting hole 55 following the small-diameter portion 64. The diameter of the small-diameter portion 64 of the potentiometer shaft 60 is the same as the diameter of the lower portion 56 of the mounting hole. The outer peripheral surface of the small-diameter portion 64 slidably contacts the inner peripheral surface of the lower portion 56 of the mounting hole in the insertion direction and the circumferential direction.Since, as described above, the small-diameter portion 64 and the lower portion 56 of the mounting hole are provided, it is possible to prevent the potentiometer shaft 60 from being inserted obliquely with respect to the valve stem 50. The potentiometer shaft 60 is guided coaxially with the valve stem 50 along the axis L. Then, the potentiometer shaft 60 is further inserted until the large-diameter portion 62 abuts against the end surface 51b of the valve stem 50. At this time, the potentiometer shaft 60 is in the inserted state before press-fitting. The fitting shaft portion 61 and the large-diameter portion 62 of the potentiometer shaft 60 protrude from the mounting hole 55.

[0044] Next, as in Fig. As illustrated in Figure 6, the fitting shaft portion 61 of the potentiometer shaft 60 passes through the through hole 72d provided in the meter mounting portion 72 of the potentiometer base 70. The potentiometer base 70 is positioned on the projections 43c, 43c of the lower housing 43. Then, the screws 78, 78 are screwed into the projections 43c, 43c to fix the potentiometer base 70 to the lower housing 43. The lower housing 43 is joined to the valve body 10 by ultrasonic welding. Thus, the potentiometer base 70 is fixed with respect to the valve body 10.

[0045] Next, as in Fig. As illustrated in FIG. 7, the fitting shaft portion 61 of the potentiometer shaft 60 is passed through the fitting hole 81a provided in the rotor 81 of the potentiometer 80, and the fitting shaft portion 61 is fitted into the fitting hole 81a. The potentiometer 80 is disposed in the recess 72c of the meter mounting portion 72 of the potentiometer base 70. The potentiometer 80 is attached and fixed by soldering or the like. Alternatively, the potentiometer base 70 may be fixed to the lower case 43 after the potentiometer 80 is attached to the potentiometer base 70.

[0046] Next, the potentiometer shaft 60 is positioned around the axis L. As shown in the Fig. 8 and Fig. 9A, the potentiometer shaft 60 was fitted into the fitting hole 81a of the rotor 81. The positioning of the potentiometer shaft 60 about the axis L is performed by rotating the potentiometer shaft 60 about the axis L in the mounting hole 55 such that a correct signal relating to the rotational position of the ball valve element 20 is output from the potentiometer 80. After the positioning of the potentiometer shaft 60 is completed, as shown in Fig. 9B, the potentiometer shaft 60 is further inserted and pressed down. In this way, the large-diameter portion 62 of the potentiometer shaft 60 is press-fitted into the upper portion 57 of the mounting hole 55. The potentiometer shaft 60 is fixed to the valve stem 50 in the state in which the potentiometer shaft 60 has been positioned. More specifically, the large-diameter portion 62 is press-fitted into the upper end portion 57a ​​of the upper portion 57 of the mounting hole. Thus, the potentiometer shaft 60 is fixed to the upper end portion 57a ​​by press-fitting.

[0047] Finally, the upper housing (not shown) is attached to the lower housing 43 to complete the flow channel switching valve 1.

[0048] As described above, in the flow channel switching valve 1 according to the present embodiment, the potentiometer shaft 60 includes the small-diameter portion 64, the medium-diameter portion 63, and the large-diameter portion 62, which are sequentially connected in the direction of the axis L from the ball valve element 20 side. The potentiometer shaft 60, in the fitted state before being press-fitted into the mounting hole 55, is rotatably supported in the mounting hole 55 about the axis L. The mounting hole 55 provided in the valve stem 50 is provided with the upper end portion 57a ​​of the upper portion 57 of the mounting hole, which serves as a press-fit portion into which the large-diameter portion 62 of the potentiometer shaft 60 is press-fitted.With this configuration, the potentiometer shaft 60 in the flow channel switching valve 1 can be rotated around the axis L to perform positioning in the state where the potentiometer shaft 60 is inserted into the mounting hole 55, and can be press-fitted and fixed after positioning. Accordingly, it is possible to further reduce an error in the output of the potentiometer 80 due to the tolerances of the ball valve element 20, the valve stem 50, and the potentiometer shaft 60. Thus, it is possible to effectively improve the accuracy of the rotational position of the ball valve element 20.

[0049] Furthermore, the potentiometer shaft 60 is press-fitted into the upper end portion 57a ​​of the mounting hole 55 of the valve stem 50, and the upper end portion 57a ​​is displaced by the bearing portion 45 and the gear 41 in the direction of the axis L. Thus, in the flow channel switching valve 1, it is possible to avoid the influence of deformation of the valve stem 50 due to the press-fitting of the potentiometer shaft 60. For example, it is possible to avoid excessive compression of the O-ring 54 or contact of the valve stem 50 with the bearing portion 45 due to deformation of the valve stem 50 such that its diameter increases. Thus, it is possible to prevent the rotation of the valve stem 50 from being hindered and to ensure smooth rotation of the ball valve element 20. In addition, it is possible to avoid the influence of deformation of the valve stem 50 (mounting hole 55) due to the press-fitting of the gear 41.Accordingly, it is possible to prevent the potentiometer shaft 60 from being pressed in obliquely. Thus, it is possible to effectively improve the accuracy of the rotational position of the ball valve element 20.

[0050] Furthermore, the mounting hole 55 includes the mounting hole lower portion 56 with which the small-diameter portion 64 of the potentiometer shaft 60 slidably contacts in the axial direction (the direction of the axis L) and the circumferential direction (the direction around the axis L). The mounting hole lower portion 56 is provided to be displaced by the gear 41 in the direction of the axis L. With this configuration, in the flow channel switching valve 1, it is possible to avoid the influence of deformation of the valve stem 50 (mounting hole 55) due to the press-fitting of the gear 41. Accordingly, it is possible to prevent the potentiometer shaft 60 from being press-fitted obliquely, and it is possible to effectively improve the accuracy of the rotational position of the ball valve element 20.

[0051] In the flow channel switching valve 1 according to the present embodiment, the small-diameter portion 64 provided near the lower end of the potentiometer shaft 60 is passed through the lower portion 56 of the mounting hole, and the large-diameter portion 62 provided near the upper end of the potentiometer shaft 60 is press-fitted into the upper end portion 57a ​​of the upper portion 57 of the mounting hole. However, the present invention is not limited to this. That is, the mounting hole 55 (the lower portion 56 of the mounting hole and the upper portion 57 of the mounting hole) of the valve stem 50 and the potentiometer shaft 60 can have any configurations as long as the configurations do not impair the object of the present invention. (Second embodiment)

[0052] A configuration of a flow channel switching valve according to a second embodiment of the present invention will be described below with reference to Fig. 10 described.

[0053] Fig. 10 is a view illustrating the flow channel switching valve according to the second embodiment of the present invention. Fig. 10 is a sectional view illustrating a state in which a potentiometer shaft is press-fitted into a mounting hole of a valve stem. Fig. 10A illustrates a state in which the potentiometer shaft has been inserted into the mounting hole of the valve stem (inserted state before press-fitting), and Fig. 10B illustrates a state in which the potentiometer shaft has been pressed into and fixed to the mounting hole of the valve stem.

[0054] A flow channel switching valve 2 of the present embodiment has the same configuration as that of the flow channel switching valve 1 of the first embodiment described above, except that the flow channel switching valve 2 includes a potentiometer shaft 60A having a different configuration from that of the potentiometer shaft 60 instead of the potentiometer shaft 60. In the flow channel switching valve 2, the same components as those of the flow channel switching valve 1 described above are denoted by the same reference numerals, and their descriptions are omitted.

[0055] The potentiometer shaft 60A includes a fitting shaft portion 61, a large-diameter portion 62A, a medium-diameter portion 63A, and a small-diameter portion 64A sequentially from the upper side to the lower side in the axial direction thereof. In other words, the small-diameter portion 64A, the medium-diameter portion 63A, and the large-diameter portion 62A are connected sequentially in the direction of the axis L from the ball valve element 20 side to the gear 41 side.

[0056] The large diameter portion 62A is formed in a circular columnar shape. The large diameter portion 62A has the same diameter (including substantially the same diameter) as the diameter of the upper portion 57 of the mounting hole 55. The middle diameter portion 63A is formed in a circular columnar shape. The middle diameter portion 63A has a diameter smaller than the diameter of the large diameter portion 62A and the diameter of the upper portion 57 of the mounting hole and larger than the diameter of the small diameter portion 64A. The middle diameter portion 63A connects the large diameter portion 62A and the small diameter portion 64A. The small diameter portion 64A is formed in a circular columnar shape.The small-diameter portion 64A has the same diameter (including substantially the same diameter) as the diameter of the lower portion 56 of the mounting hole of the mounting hole 55. The diameter of the intermediate-diameter portion 63A is slightly larger than the diameter of the small-diameter portion 64A (that is, the diameter of the lower portion 56 of the mounting hole). In this embodiment, the diameter of the intermediate-diameter portion 63A is approximately 0.04 to approximately 0.06 mm larger than the diameter of the small-diameter portion 64A. Accordingly, the intermediate-diameter portion 63A is press-fitted into an upper end portion 56a of the lower portion 56 of the mounting hole.

[0057] When assembling the flow channel switching valve 2, as shown in Fig. 10A illustrates that the potentiometer shaft 60A is inserted into the mounting hole 55 of the valve stem 50. The diameter of the small-diameter portion 64A of the potentiometer shaft 60A is the same as the diameter of the lower portion 56 of the mounting hole, which serves as the guide portion. The outer peripheral surface of the small-diameter portion 64A slidably contacts the inner peripheral surface of the lower portion 56 of the mounting hole in the insertion direction and the circumferential direction. Furthermore, the diameter of the large-diameter portion 62A of the potentiometer shaft 60A is the same as the diameter of the upper portion 57 of the mounting hole, which serves as the guide portion. The outer peripheral surface of the large-diameter portion 62A slidably contacts the inner peripheral surface of the upper portion 57 of the mounting hole in the insertion direction and the circumferential direction.Since, as described above, the small-diameter portion 64A and the lower portion 56 of the mounting hole and the large-diameter portion 62A and the upper portion 57 of the mounting hole are provided, it is possible to prevent the potentiometer shaft 60A from being inserted obliquely with respect to the valve stem 50, and the potentiometer shaft 60A is guided coaxially with the valve stem 50 along the axis L. Then, as shown in . Fig. 10B illustrates that when the potentiometer shaft 60A is further inserted, the intermediate diameter portion 63A is press-fitted into the upper end portion 56a of the lower portion 56 of the mounting hole, which serves as a press-fit portion. Thus, the potentiometer shaft 60A is fixed to the valve stem 50. The upper end portion 56a functions as a guide portion and a press-fit portion.

[0058] The flow channel switching valve 2 of the second embodiment also has the functions and effects similar to or the same as those of the flow channel switching valve 1 of the first embodiment described above.

[0059] Specifically, in the flow channel switching valve 2, the upper end portion 56a of the lower mounting hole portion 56, which serves as a press-fit portion into which the medium-diameter portion 63A is press-fitted, is provided in the mounting hole 55. The mounting hole 55 is provided with the lower mounting hole portion 56 and the upper mounting hole portion 57 as two guide portions with which the small-diameter portion 64A and the large-diameter portion 62A slidably contact in the axial direction and the circumferential direction. With this configuration, in the flow channel switching valve 2, the small-diameter portion 64A and the large-diameter portion 62A contact the two guide portions to guide the movement of the potentiometer shaft 60A.Thus, it is possible to more effectively prevent the potentiometer shaft 60A from being pressed obliquely into the valve stem 50.

[0060] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Those skilled in the art may appropriately add, delete, or change the design of a component with respect to the above-described embodiments, or appropriately combine features of the embodiments. The modified or combined embodiments are included within the scope of the present invention as long as they do not affect the essence of the present invention. List of reference symbols

[0061] 1, 2 ... flow channel switching valve, 10 ... valve body, 10a ... left wall portion, 10b ... front wall portion, 10c ... right wall portion, 11 ... first flow channel, 12 ... second flow channel, 13 ... third flow channel, 11a, 12a, 13a ... orifice, 14 ... valve chamber, 20 ... ball valve element, 21 ... first port, 22 ... second port, 23 ... third port, 24 ... valve stem insertion port, 25 ... switching flow path, 30 ... seat element, 30a ... annular groove, 31 ... seal element, 40 ... drive unit, 41 ... gear, 41a ... through hole, 41b ... upper surface, 43 ... lower housing, 43a ... bottom wall, 43b ... inner peripheral wall portion, 45 ... bearing portion, 50 ... valve stem, 51 ... circular column section, 51a ... flat section, 51b ... end face, 52 ... angled column section, 53 ... stopper section, 54 ... O-ring, 55 ... mounting hole, 56 ... lower section of the mounting hole, 56a ... upper end section, 57 ...upper section of the mounting hole, 57a ... upper end section, 60 ... potentiometer shaft, 61 ... fitting shaft section, 62 ... large diameter section, 63 ... medium diameter section, 64 ... small diameter section, 70 ... potentiometer base, 71 ... base body section, 72 ... meter mounting section, 72a ... lower wall section, 72b ... peripheral wall section, 72c ... recess, 72d ... through hole, 80 ... potentiometer, 81 ... rotor, 81a ... fitting hole, 82 ... meter body section.

Claims

[1] A flow channel switching valve (1, 2) comprising a valve body (10) provided with a valve chamber (14) and a plurality of flow channels (11, 12, 13) communicating with the valve chamber (14), a valve element rotatably housed in the valve chamber (14) and switching a connection of the flow channels (11, 12, 13) in accordance with a rotational position, a valve stem (50) fixed to the valve element along a rotational axis of the valve element, and a drive unit (40) rotating the valve element via the valve stem (50), the flow channel switching valve (1, 2) comprising: a rotation angle output shaft press-fitted into a mounting hole (55) provided in an end surface (51b) of the valve stem (50); and a rotation angle detection unit that detects a rotation angle of the rotation angle output shaft around the rotation axis, wherein the rotation angle output shaft has a small diameter portion (64), a medium diameter portion (63) and a large diameter portion (62) connected in sequence in a direction of the rotation axis, and is supported in the mounting hole (55) in an inserted state before being press-fitted into the mounting hole (55) so as to be rotatable about the rotation axis, and wherein the mounting hole (55) is provided with a press-fit portion into which a portion of the small diameter portion (64), the medium diameter portion (63) and the large diameter portion (62) is press-fitted. [2] Flow channel switching valve (1, 2) according to claim 1, wherein the valve stem (50) is pressed into a through hole (41a) provided in a gear (41) of the drive unit (40), and wherein the press-fit portion is provided at a position shifted from the gear (41) in the direction of the rotation axis. [3] The flow channel switching valve (1, 2) according to claim 2, wherein the mounting hole (55) has a guide portion with which at least one of the other portions of the small diameter portion (64), the middle diameter portion (63) and the large diameter portion (62) except the portion press-fitted into the press-fit portion slidably comes into contact in an axial direction and in a circumferential direction. [4] The flow channel switching valve (1, 2) according to claim 3, wherein the guide portion is provided to be displaced by the gear (41) in the direction of the rotation axis. [5] Flow channel switching valve (1, 2) according to claim 3 or 4, wherein the guide portion is provided to be displaced in the direction of the rotation axis by a bearing portion (45) rotatably supporting the valve stem (50). [6] The flow channel switching valve (1, 2) according to claim 1, wherein the mounting hole (55) is provided with the press-fit portion into which the intermediate diameter portion (63) is press-fitted, and two guide portions with which the small diameter portion (64) and the large diameter portion (62) slidably contact in an axial direction and in a circumferential direction.

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