Valve mechanism

Abstract

To provide a valve device capable of preventing worm lock and improving stability in a switching operation of a valve port by a main valve, by reducing friction between a worm and a part supporting the worm.SOLUTION: A rotary type switch valve 100 as a valve device includes a valve body 1, a main valve 3, and a driving portion 5. The main valve 3 is rotationally driven by the driving portion 5 and stopped by a main valve stopper 9 of the valve body 1. The driving portion 5 includes a worm 52 rotated by an electric motor 51, and a worm wheel 54 engaged with the worm 52. The worm 52 is supported by a rotation supporting portion 53 at least at one place in a manner of being rotatable about an axis A and movable a direction of the axis A. The rotation supporting portion 53 has a lock prevention mechanism for preventing lock of the worm 52.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a valve device. [Background technology]

[0002] As a valve device for controlling the flow rate of a fluid, a rotary switching valve including a valve housing, a main valve, an auxiliary valve, and a drive unit is known (see, for example, Patent Documents 1 and 2). In these rotary switching valves, the auxiliary valve is rotationally driven by a worm gear having a worm rotated by an electric motor and a worm wheel meshing with the worm, and the rotation of the auxiliary valve is transmitted to the main valve to switch the valve port. The main valve stops rotating at a predetermined switching position by abutting against a valve stopper of the valve housing, and the auxiliary valve stops rotating by abutting against the auxiliary valve stopper of the main valve, but if a rotation signal is sent to the electric motor in the same rotation direction thereafter, the worm moves in the thrust direction, which is the axial direction of the worm, and stops by abutting against the worm support unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-270639 A [Patent Document 2] Patent Publication No. 2021-124119 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned worm gear, when the worm and the worm support portion come into contact with each other, the worm becomes tense between the meshing portion of the worm wheel and the worm support portion, and frictional forces are generated in each of the meshing portion and the worm support portion, which can prevent the worm from rotating in the reverse direction (in this specification, this phenomenon is defined and used as "worm lock"). This may hinder the stability of the main valve, i.e., the switching operation of the valve port by the valve body.

[0005] An object of the present invention is to provide a valve gear that can prevent worm lock by reducing friction between a worm and a portion that supports the worm, thereby improving the stability of the switching operation of the valve port by the valve body. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the valve device of the present invention is a valve device comprising a valve body, a valve element, and a drive unit, the valve element is rotationally driven by the drive unit and the rotation of the valve element is stopped by a stopper of the valve body, the drive unit comprises a worm rotated by an electric motor, and a worm wheel meshing with the worm, the worm is supported by at least one rotation support unit to be rotatable about its axis and movable in the axial direction, and the rotation support unit has a lock prevention mechanism that prevents the worm from locking. The lock prevention mechanism is constituted by an annular bearing provided on the rotation support portion, the worm has a reduced diameter portion inserted into the bearing and a step portion extending radially outward from the reduced diameter portion, and when the rotation of the valve body is stopped, a play in the axial direction is provided between the step portion and an end face of the bearing, and the step portion moves toward the axial proximity side approaching the end face of the bearing and abuts against the end face of the bearing, thereby restricting movement of the worm toward the axial proximity side, and when the step portion abuts against the end face of the bearing, the worm is supported by the bearing to be rotatable about its axis. It is characterized by:

[0007] According to the present invention, the worm is supported by a rotation support part having a lock prevention mechanism so as to be rotatable about its axis and movable in the axial direction. Therefore, when the electric motor continues to rotate in response to a rotation signal in the same rotation direction after the valve disc stops rotating, even if the worm moves in its axial direction and comes into contact with the rotation support part, the worm, which has been prevented from locking, can rotate about its axis, thereby reducing the tension of the worm, the frictional force at the meshing part between the worm and the worm wheel, and the frictional force between the worm and the rotation support part. Therefore, by reducing the friction between the worm and the part that supports the worm, it is possible to prevent worm lock, and it is possible to obtain a valve device that improves the stability of the switching operation of the valve port by the valve disc.

[0008] Also ,child According to this configuration, a lock prevention mechanism is formed by the bearing provided in the rotation support portion, which prevents the above-mentioned worm lock and makes it possible to restrict axial movement of the worm by the end face of this bearing. Furthermore, with this configuration, when the valve body stops rotating, there is an axial backlash between the step of the worm and the end face of the bearing, so that the worm can move in the axial direction of the worm when the electric motor continues to rotate due to a rotation signal in the same rotation direction after the valve body stops rotating. As a result, when the worm moves in the axial direction and abuts against the bearing, the worm can be rotated in the reverse direction to move only the worm by the amount of the above-mentioned axial backlash. This reduces the frictional force generated in the meshing portion, making it easier to prevent worm lock.

[0009] In addition, it is preferable that there is a radial backlash between the worm and the inner diameter of the bearing. With this configuration, when the rotation of the electric motor continues by a rotation signal in the same rotation direction after the valve body stops rotating, even if the worm moves in the thrust direction, which is the axial direction of the worm, and abuts against the end face of the bearing, the worm can be displaced by the radial backlash or slide along the inner diameter of the bearing. This prevents the worm from being stretched between the meshing portion and the bearing due to the displacement or sliding of the worm, and reduces the frictional force generated in the meshing portion or the bearing.

[0011] In addition, it is preferable that the bearing is a bearing having an inner ring, an outer ring, and a rolling member, and that the axial movement of the worm is restricted by abutting against an end face of the inner ring. With this configuration, the bearing constituted by the bearing can prevent worm lock.

[0012] Furthermore, the bearing may be a bush made of a material having low sliding resistance and formed into a cylindrical shape. With this configuration, worm lock can be prevented by the bearing constituted by a bush made of a material having low sliding resistance and formed into a cylindrical shape.

[0013] Also, The valve device of the present invention comprises a valve body, a valve element, and a drive unit, the valve element is rotationally driven by the drive unit and the rotation of the valve element is stopped by a stopper of the valve body, the drive unit comprises a worm rotated by an electric motor and a worm wheel meshing with the worm, the worm is supported by at least one rotation support part to be rotatable about its axis and movable in the axial direction, the rotation support part has a lock prevention mechanism that prevents the worm from locking, The rotation support portion is disposed on one side of the worm in the axial direction, which is the side where the electric motor is located. The drive unit includes a biasing member that biases the worm toward one side in the axial direction, and the biasing force of the biasing member is greater than a thrust force, which is an axial force acting on the worm toward the other side in the axial direction of the worm due to engagement with the worm wheel. According to this configuration, even if the electric motor continues to rotate in a rotation signal in the same rotation direction after the valve disc stops rotating and the worm moves to one side in the axial direction, the rotation support portion arranged on one side of the worm in the axial direction can prevent worm lock.

[0014] Also ,childWith this configuration, after the rotation of the valve body stops, the electric motor continues to rotate due to a rotation signal in the same rotational direction, and even if the worm attempts to move to the other axial side, the movement can be suppressed by the biasing member, which has a biasing force greater than the thrust force acting on the worm toward the other axial side.

[0015] In addition, it is preferable that the rotation support portion is also disposed on the other axial side of the worm. According to this configuration, the worm can be supported by the rotation support portions disposed on one axial side and the other axial side of the worm, so that the rotation support portions disposed on both axial ends of the worm can suppress the worm from swinging in a direction intersecting the axial direction.

[0016] In addition, the rotary switching valve of the present invention is a valve device as described above, comprising a valve chamber provided inside the valve body, a valve seat portion having a plurality of valve ports opening into the valve chamber, a main valve provided inside the valve body rotatably about a central axis intersecting the valve seat portion, and a sub-valve provided rotatably about the central axis for opening and closing a pressure equalizing hole of the main valve, wherein the valve ports are switched by transmitting rotation of the sub-valve rotated by the drive portion to the main valve. With this configuration, it is possible to obtain a rotary switching valve that can prevent worm lock by reducing friction between the worm and a portion supporting the worm, and improves the stability of the switching operation of the valve ports by the main valve. Effect of the Invention

[0017] According to the present invention, by reducing friction between the worm and the part that supports the worm, it is possible to prevent worm lock and obtain a valve device that improves the stability of the switching operation of the valve port by the valve body. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is an assembled cross-sectional view of the valve device according to the embodiment of the present invention. [Diagram 2]FIG. [Diagram 3] FIG. 4 is a cross-sectional view showing a state in which rotation of the sub-valve and the main valve about the central axis is restricted. [Figure 4] FIG. 13 is a diagram showing the worm when the rotation of the sub-valve and the main valve about the central axis is restricted. [Diagram 5] FIG. 4 is a diagram showing a worm in a state in which it is in contact with a rotation support portion. [Figure 6] FIG. 11 is a cross-sectional view showing a rotation support part in a first modified example. [Figure 7] FIG. 11 is a cross-sectional view showing a drive unit and a worm in a second modified example. [Figure 8] FIG. 2A is a schematic diagram of the refrigeration cycle system showing a state during cooling operation, and FIG. 2B is a schematic diagram of the refrigeration cycle system showing a state during heating operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of a rotary switching valve 100, which is a valve device in the present invention, will be described with reference to Figs. 1 to 5 and 8. In Fig. 1, the arrows X and Y are mutually perpendicular directions, and the arrow X is the axial direction of the valve body 1 and the central axis 6, and is referred to as the "axial X direction". One side of the axial X direction is referred to as the "upper side X1", and the other side is referred to as the "lower side X2". The cross direction intersecting the axial X direction is indicated by the arrow Y and is referred to as the "radial direction Y". In particular, in the radial direction Y, the side where the central axis 6 is located is referred to as the "inner side", and the opposite side of the inner side is referred to as the "outer side". This is merely for convenience of explanation, and does not necessarily coincide with the direction in the actual use state of the rotary switching valve 100, and does not limit the direction in the actual use state of the rotary switching valve 100.

[0020] The rotary switching valve 100 comprises a valve body 1, a valve seat member 2, a main valve 3 (valve element), an auxiliary valve 4, a drive unit 5, and a central shaft 6. The valve body 1 comprises a cylindrical first cylindrical portion 10 extending in the direction of axis X, and a cylindrical second cylindrical portion 11 with a bottom that is continuous with the first cylindrical portion 10 and has a smaller diameter than the first cylindrical portion 10, and accommodates the main valve 3, the auxiliary valve 4, the drive unit 5, and the central shaft 6. The inside of the first cylindrical portion 10 forms a valve chamber 10a. The inside of the second cylindrical portion 11 forms an accommodation portion 11a that mainly accommodates the drive unit 5 and the like.

[0021] The valve seat member 2 includes a cylindrical valve seat portion 20 and a flange portion 21 formed on the outer periphery of the valve seat portion 20. The valve seat portion 20 is fitted into the valve body 1 so that its outer periphery contacts the inner periphery of the first cylindrical portion 10, and its upper surface forms a valve seat surface 20a extending in the radial direction Y. As shown in Fig. 8(A) and (B), the valve seat portion 20 is provided with four valve ports 20D, 20S, 20C, and 20E that penetrate from the lower end of the valve seat portion 20 to the valve seat surface 20a and open into the valve chamber 10a. The valve ports 20D, 20S, 20C, and 20E open at positions spaced 90° apart from each other.

[0022] 8(A) and (B), the four valve ports are composed of a D port 20D communicating with the valve chamber 10a and the refrigerant discharge side of the compressor P, an S port 20S communicating with the refrigerant suction side of the compressor P, a C switch port 20C communicating with the outdoor heat exchanger 60 side, and an E switch port 20E communicating with the indoor heat exchanger 80 side. A coupling pipe 8 (only shown in FIG. 1) is connected to each of the ports 20D, 20S, 20C, and 20E to form a refrigerant flow path. The flange portion 21 is fixed to the valve body 1 by welding with its upper surface in contact with the lower end surface of the first cylindrical portion 10.

[0023] The main valve 3 is a member made of resin, and is provided inside the valve body 1 so as to be rotatable about a central axis 6 and displaceable in the direction of the axis X. As shown in Fig. 1, the main valve 3 includes a bowl-shaped portion 30 that opens to the lower side X2 (the valve seat portion 20 side), and a cylindrical piston portion 31 that is continuous with the bowl portion 30 and extends to the upper side X1. The bowl portion 30 is formed with a low-pressure flow path 30L and a high-pressure flow path 30H that open toward the valve seat surface 20a, and a pressure equalizing hole 30a that communicates from the ceiling of the low-pressure flow path 30L to the accommodation portion 11a.

[0024] The low-pressure flow passage 30L is a valve passage that communicates between two adjacent ports among the above-mentioned valve ports 20D, 20S, 20C, and 20E, and is provided opposite the high-pressure flow passage 30H across the central axis 6. The low-pressure flow passage 30L is provided with a rib 32 that protrudes from its open end edge toward the lower side X2, and the lower end surface of the rib 32 forms a low-pressure seal surface 32a. The low-pressure seal surface 32a is capable of sliding contact with the valve seat surface 20a, and two of the above-mentioned four ports 20D, 20S, 20C, and 20E are communicated with each other by a space surrounded by the low-pressure seal surface 32a and the valve seat surface 20a and separated from the valve chamber 10a.

[0025] A reinforcing member 7 is installed in the low-pressure flow path 30L from its inner wall in the radial direction Y to its outer wall in the radial direction Y. The reinforcing member 7 is a member for preventing the low-pressure flow path 30L from being deformed by stress caused by the pressure difference between the inside and the outside of the main valve 3, and is formed in a rod shape from a material such as metal or resin, and is fixed into the low-pressure flow path 30L by press-fitting or the like.

[0026] The high-pressure flow passage 30H is a valve passage that communicates between two adjacent ports among the valve ports 20D, 20S, 20C, and 20E. A notch 30H1 is formed in the wall on the outer side in the radial direction Y of the high-pressure flow passage 30H, facing inward in the radial direction Y when viewed in cross section in the figure. This makes the high-pressure flow passage 30H a constantly open space that is not separated from the valve chamber 10a.

[0027] A pair of sliding ribs 30b protruding toward the lower side X2 are formed on the bottom surface of the bowl portion 30. As shown in Figures 8(A) and (B) , the sliding ribs 30b are formed at intervals in the circumferential direction on a semicircular portion on the side where the high-pressure flow passage 30H is formed on the bottom surface of the bowl portion 30.

[0028] The piston portion 31 is formed so as to fit a piston ring R around it, and the piston ring R is adapted to slide against the inner peripheral surface of the second cylindrical portion 11 when the main valve 3 is displaced in the direction of the axis X, as shown in Fig. 1. A cylindrical recess that opens to the upper side X1 is formed in the center of the piston portion 31, and this recess constitutes an sub-valve accommodating chamber 31a that accommodates the sub-valve 4.

[0029] 1, a columnar sub-valve stopper 31a1 (stopper) is formed on the inner circumferential surface of the sub-valve accommodating chamber 31a, protruding inward in the radial direction Y and extending in the direction of the axis X. As shown in FIG. 3, two sub-valve stoppers 31a1 are formed circumferentially spaced apart on the circumference around the central axis 6 (around the axis X). The sub-valve stopper 31a1 is a part that abuts against an expanded diameter portion 40a of the sub-valve 4 described later to stop rotation of the sub-valve 4.

[0030] The main valve clutch portion 33 is formed on the bottom surface of the sub-valve accommodating chamber 31a. As shown in FIG. 1, the main valve clutch portion 33 is formed of three main valve protrusions 33a that are convex toward the upper side X1 and are formed at equal intervals in the circumferential direction on the circumference around the central axis 6. Each main valve protrusion 33a has a trapezoidal cross section about the central axis 6, and both left and right ends about the central axis 6 are tapered surfaces that are inclined in a direction approaching each other toward the upper side X1. One of these main valve protrusions 33a has an opening at the end of the upper side X1 of the above-mentioned pressure equalizing hole 30a. The upper surface of the main valve protrusion 33a where this pressure equalizing hole 30a opens forms a surface that contacts the lower end surface of the sub-valve protrusion 42a described later.

[0031] The center of the bottom surface of the sub-valve accommodating chamber 31a constitutes a bearing portion for the central shaft 6, and a shaft insertion hole 3a is formed in the center of this bearing portion, penetrating along the direction of the axis X to the lower end of the bowl portion 30. A lower portion 6b of the central shaft 6, which will be described later, is inserted into the shaft insertion hole 3a, whereby the main valve 3 is supported so as to be rotatable about the central shaft 6 and displaceable in the direction of the axis X between a first switching position (switching position, position shown in FIG. 8(A)) where the central shaft 6 abuts against a main valve stopper 9 (stopper), and a second switching position (switching position, position shown in FIG. 8(B)).

[0032] The sub-valve 4 is a member made of metal, and is provided so as to be rotatable about a central axis 6 and displaceable in the direction of the axis X, similar to the main valve 3. As shown in Fig. 1, the sub-valve 4 includes a substantially disk-shaped flange portion 40 accommodated in the sub-valve accommodating chamber 31a, and a boss portion 41 formed in the center of the flange portion 40 and extending in the direction of the axis X. As shown in Fig. 3, an expanded diameter portion 40a is formed in substantially half of the circumferential portion of the flange portion 40, protruding radially outwardly from the other portions, and one circumferential end of the expanded diameter portion 40a is configured to abut against one of the sub-valve stoppers 31a1 described above, and the other circumferential end of the expanded diameter portion 40a is configured to abut against the other of the sub-valve stoppers 31a1.

[0033] Specifically, one circumferential end or the other circumferential end of the enlarged diameter portion 40a is adapted to come into contact with the sub-valve stopper 31a1 when the sub-valve 4 rotates about the central axis 6 in a state in which the main valve 3 is in contact with the main valve stopper 9 at the first switching position or the second switching position and its rotation is restricted (a state in which rotation is stopped). This contact restricts the rotation of the sub-valve 4 about the central axis 6. In this embodiment, as shown in FIG. 3, the maximum amount of rotation of the sub-valve 4 about the central axis 6 with respect to the valve body 1 is set to about 210° depending on the positional relationship of the sub-valve stoppers 31a1 of the main valve 3 (how many degrees apart they are in the circumferential direction).

[0034] As shown in FIG. 1, the sub-valve clutch part 42 is formed on the lower surface of the flange part 40. The sub-valve clutch part 42 is formed by three sub-valve protrusions 42a that are convex toward the lower side X2 on the same circumference as the main valve protrusion 33a and are formed at equal intervals in the circumferential direction on the circumference around the central axis 6. One of the main valve protrusions 33a can be positioned between one of the sub-valve protrusions 42a and the other sub-valve protrusions 42a, so that the main valve clutch part 33 and the sub-valve clutch part 42 mesh with each other. The sub-valve protrusions 42a have a trapezoidal cross-sectional shape around the central axis 6, and the left and right ends around the central axis 6 are tapered surfaces that are inclined toward each other as they approach the lower side X2.

[0035] As described above, the lower end surface of the sub-valve convex portion 42a is configured to contact the upper surface of the main valve convex portion 33a, and this surface is configured to open and close the pressure equalizing hole 30a while sliding against the upper surface of the main valve convex portion 33a in accordance with the rotation of the sub-valve 4.

[0036] A pressure equalizing passage (not shown), which can communicate with the pressure equalizing hole 30a, is formed between one sub-valve protrusion 42a and the other sub-valve protrusion 42a on the underside of the flange portion 40. Therefore, when the lower end surface of the sub-valve protrusion 42a closes the pressure equalizing hole 30a, the high pressure valve chamber 10a and the low pressure low pressure passage 30L are separated, but when the pressure equalizing passage and the pressure equalizing hole 30a are in communication, the pressure of the fluid on the upper side X1 outside the main valve 3 escapes to the low pressure passage 30L (low pressure side), so that the pressures on the upper side X1 of the main valve 3 and the low pressure passage 30L become uniform.

[0037] A square hole 41a opening to the upper side X1 is formed at the center of the boss portion 41. The square hole 41a is a portion through which the sub-valve 4 and a worm wheel 54 described later can transmit rotational force around the central axis 6 to each other, and is formed so that a cam portion 54b of the worm wheel 54 can be fitted into it, as shown in Fig. 1. A shaft insertion hole 4a penetrating along the axis X direction to the lower end of the flange portion 40 is formed at the center of the bottom of the square hole 41a. An upper portion 6a of the central shaft 6 described later is inserted into the shaft insertion hole 4a, thereby supporting the sub-valve 4 so as to be rotatable around the central axis 6 and displaceable in the axis X direction.

[0038] The drive unit 5 is a part that drives the sub-valve 4 to rotate, and includes a case 50, an electric motor 51, a worm 52, a rotation support 53, a worm wheel 54, a first coil spring 55 (biasing member), and a second coil spring 56 (shown only in FIG. 1), as shown in FIG. 2. In addition, in FIG. 2, FIG. 4, and FIG. 5, which are referred to in the following description of the drive unit 5, a direction extending in a direction perpendicular to the radial direction Y in a plane when the rotary switching valve 100 is viewed in a plan view is defined as the axial direction of the worm 52, and is particularly referred to as the axial direction A. In addition, in the axial direction A, the side where the electric motor 51 is located is defined as one side A1, and the opposite side is defined as the other side A2. In addition, the radial direction Y also represents the radial direction of the worm 52.

[0039] The case 50 constitutes a part of the second cylindrical portion 11 of the valve body 1, and includes a housing portion 50a extending in the axial direction A, a connecting portion 50b fixed to one side A1 of the housing portion 50a, and a can 50c fixed to one side A1 of the connecting portion 50b. The housing portion 50a is formed in a cylindrical shape extending in the axial direction A, and houses a worm 52 therein. The connecting portion 50b is formed in a tubular shape, and is welded and fixed to the housing portion 50a with the other side A2 portion fitted into the one side A1 of the housing portion 50a. The can 50c is formed in a cap shape protruding on the one side A1, and the open end edge of the other side A2 is fixed to the end of the one side A1 of the connecting portion 50b by welding, thereby sealing the internal space of the housing portion 50a.

[0040] In this embodiment, the electric motor 51 is a stepping motor, and includes a magnet rotor 51a that is installed inside the can 50c and rotatable around the axis A (around the axis), and a stator coil 51b that is fixed to the outer periphery of the magnet rotor 51a with the can 50c sandwiched therebetween. The electric motor 51 is capable of adjusting the direction and amount of rotation of the worm 52 by a control unit (not shown). For example, in this embodiment, the control unit sends a predetermined pulse to rotate the worm 52 in a first direction, which is a direction in which the sub-valve 4 rotates left around the central axis 6, and in a second direction, which is the opposite direction to the first direction. The relationship between the predetermined pulse and the rotation angle of the sub-valve 4 is, for example, 210° for 1400 pulses, and since the maximum amount of rotation of the sub-valve 4 around the central axis 6 with respect to the valve body 1 is about 210° as described above, theoretically, the sub-valve 4 rotates by the maximum amount of rotation for 1400 pulses.

[0041] The worm 52 is a metal member that is rotationally driven by the electric motor 51, is fixed to the center of the magnet rotor 51a, extends in the direction of the axis A, and is provided so as to be rotatable around the axis A integrally with the magnet rotor 51a. The worm 52 includes, from one side A1 toward the other side A2, a drive shaft 52a, a first reduced diameter portion 52b (reduced diameter portion), a first step portion 52c (step portion), a shaft portion 52d, a gear portion 52e, a second step portion 52f (step portion), and a second reduced diameter portion 52g (reduced diameter portion). The drive shaft 52a is a portion that constitutes the end portion of the one side A1 of the worm 52, and is fixed to the magnet rotor 51a while penetrating the center of the magnet rotor 51a.

[0042] The first reduced diameter portion 52b is formed to have a larger diameter dimension than the drive shaft 52a and extends to the vicinity of the end of the one side A1 of the connection portion 50b. The first step portion 52c is continuous with the first reduced diameter portion 52b and is formed toward the outside in the radial direction Y of the worm 52. The shaft portion 52d is continuous with the first step portion 52c, extends in the axial direction A, and is formed to have a larger diameter than the first reduced diameter portion 52b. The gear portion 52e is a portion that meshes with the teeth portion 54a of the worm wheel and is formed from the middle portion of the shaft portion 52d in the axial direction A to the other side A2. The second step portion 52f is continuous with the end of the shaft portion 52d on the other side A2 and is formed toward the inside in the radial direction Y of the worm 52. The second reduced diameter portion 52g is continuous with the second step portion 52f, extends in the axial direction A, and is formed to have approximately the same diameter as the first reduced diameter portion 52b.

[0043] The rotation support part 53 is a bearing that supports the worm 52 rotatably around the axis A and movable in the direction of the axis A, and in this embodiment, is configured as a ball bearing including an inner ring 53a, an outer ring 53b, and a ball-shaped rolling member 53c sandwiched between the inner ring 53a and the outer ring 53b. In this embodiment, the rotation support part 53 is provided on one side A1 and the other side A2 of the worm 52. The rotation support part 53 arranged on the one side A1 is fixed by fitting the outer ring 53b into the end of the one side A1 of the connection part 50b, and the first reduced diameter part 52b of the worm 52 is inserted into the inner ring 53a of the rotation support part 53. The rotation support part 53 arranged on the other side A2 is fixed by fitting an outer ring 53b into the end part of the other side A2 of the accommodating part 50a, and the second reduced diameter part 52g is inserted into the inner ring 53a of this rotation support part 53.

[0044] 2, 4, and 5, the outer peripheral surface of the first reduced diameter portion 52b and the inner peripheral surface of the inner ring 53a of the rotation support portion 53 appear to be in contact with each other, but a first backlash S1, which is a gap in the radial direction Y, is set to be generated between the outer peripheral surface and the inner peripheral surface. Similarly, a first backlash S1 is generated between the outer peripheral surface of the second reduced diameter portion 52g and the inner peripheral surface of the inner ring 53a. That is, a backlash in the radial direction Y is provided between the worm 52 and the inner diameter of the rotation support portion 53 (the inner diameter of the bearing).

[0045] The worm wheel 54 is a cylindrical member that meshes with the worm 52, that is, rotates in mesh with it, and includes a toothed portion 54a that meshes with the gear portion 52e, and a cam portion 54b that is connected to the sub-valve 4. As shown in FIG. 2, the toothed portion 54a is formed over the entire circumference of the outer circumferential surface of the worm wheel 54. As shown in FIG. 1, the cam portion 54b is a portion that protrudes to the lower side X2, and is fitted into the square hole 41a of the sub-valve 4. That is, the worm wheel 54 and the sub-valve 4 are connected by the square hole 41a and the cam portion 54b. As a result, the sub-valve 4 and the worm wheel 54 are integrated and rotate together around the central axis 6 in cooperation with each other.

[0046] 2, the first coil spring 55 is a tension coil spring installed between the magnet rotor 51a and the rotation support part 53 arranged on one side A1 of the two rotation support parts 53. The first coil spring 55 is arranged so as to circumferentially surround the first reduced diameter part 52b of the worm 52, with an end part on the one side A1 abutting against the magnet rotor 51a and an end part on the other side A2 abutting against an end face of the inner ring 53a of the rotation support part 53. The first coil spring 55 biases the worm 52 towards the one side A1 (one axial side).

[0047] 1, the second coil spring 56 is a compression coil spring disposed between the worm wheel 54 and the sub-valve 4. The second coil spring 56 is disposed so as to circumferentially surround the boss portion 41 of the sub-valve 4, with an end portion on an upper side X1 abutting against the worm wheel 54 and an end portion on a lower side X2 abutting against the flange portion 40 of the sub-valve 4. The second coil spring 56 biases the sub-valve 4 toward the lower side X2, i.e., the main valve 3.

[0048] The central shaft 6 is a main shaft extending in the direction of the axis X. As shown in FIG. 1, the central shaft 6 includes an upper portion 6a that is inserted into the center of the worm wheel 52 and the shaft insertion hole 4a of the sub-valve 4, and a lower portion 6b that is formed with a smaller diameter than the upper portion 6a and is inserted into the shaft insertion hole 3a of the main valve 3. A ball 6c is fixed to the upper end of the upper portion 6a by crimping an annular rim, and the upper portion 6a is supported via the ball 6c in a bearing groove provided in the center of the ceiling wall of the second cylindrical portion 11 of the valve body 1. The lower end of the lower portion 6b is supported by a bearing groove provided in the center of the valve seat portion 20 of the valve seat member 2. A washer 61 is fitted into the continuous portion between the upper portion 6a and the lower portion 6b, and the force generated when the main valve 3 rises to the upper side X1 is transmitted to the central shaft 6 via the washer 61.

[0049] Next, the switching of the flow paths by the main valve 3, that is, the switching operation of the valve ports 20D, 20S, 20C, and 20E will be described. First, as shown in FIG. 8(A), the main valve 3 is in the first switching position where the low pressure flow path 30L of the main valve 3 communicates the E switching port 20E with the S port 20S, and the high pressure flow path 30H communicates the D port 20D with the C switching port 20C, and the drive unit 5 is operated from this state. Then, the magnet rotor 51a rotates and the worm 52 rotates in the first direction about the axis A. Then, with the rotation of the worm 52, the worm wheel 54 meshing with the worm 52 rotates in the counterclockwise direction D1, which is the left direction about the central axis 6. At this time, the rotational force of the worm 52 and the worm wheel 54 is transmitted to the sub-valve 4 via the cam portion 54b, and the sub-valve 4 also rotates in the counterclockwise direction D1.

[0050] In this case, the lower surface of the sub-valve protrusion 42a and the upper surface of the main valve protrusion 33a are in contact with each other as shown in Fig. 1, so that the pressure equalizing hole 30a opening into the main valve protrusion 33a is closed by the sub-valve protrusion 42a. Therefore, the main valve 3 is pressed against the valve seat 20 due to the internal and external pressure difference, and even if the sub-valve 4 rotates, the main valve 3 cannot rotate due to the frictional force with the valve seat 20, and only the sub-valve 4 rotates.

[0051] When the sub-valve 4 rotates, the sub-valve protrusion 42a slides on the main valve protrusion 33a, and the pressure equalizing hole 30a is opened by the above-mentioned pressure equalizing passage formed on the lower surface of the flange portion 40 of the sub-valve 4. As a result, the pressure of the fluid on the upper side X1 outside the main valve 3 escapes into the low-pressure passage 30L (low-pressure side). Then, the main valve protrusion 33a moves to a position between the pair of sub-valve protrusions 42a, and the main valve protrusion 33a and the pair of sub-valve protrusions 42a alternately mesh with each other. In this state, the upper side X1 of the main valve 3 and the low-pressure passage 30L are pressure-equalized, so that the force pressing the main valve 3 against the valve seat 20 is reduced as described above, and the frictional force between the main valve 3 and the valve seat 20 becomes smaller than the force of meshing between the main valve protrusion 33a and the pair of sub-valve protrusions 42a.

[0052] Therefore, by rotating the sub-valve 4 about the axis X, the main valve protrusion 33a and the sub-valve protrusion 42a rotate together in the counterclockwise direction D1 while being in contact with each other. As a result, as shown in Fig. 8(B), the main valve 3 moves to the second switching position where the low-pressure flow path 30L connects the C switching port 20C and the S port 20S, and the high-pressure flow path 30H connects the D port 20D and the E switching port 20E. At this time, as shown in Fig. 3, the wall of the high-pressure flow path 30H contacts the main valve stopper 9, so that the main valve 3 is restricted from rotating further about the axis X and comes to a stopped rotation state.

[0053] In this state, when the sub-valve 4 is further rotated around the axis X, only the sub-valve 4 whose rotation is not restricted rotates in the counterclockwise direction D1 until it abuts against the above-mentioned sub-valve stopper 31a1, as shown in Fig. 3. This causes the sub-valve protrusion 42a to ride on the main valve protrusion 33a, and the pressure equalizing hole 30a is closed by the lower surface of the sub-valve protrusion 42a. Therefore, the high-pressure fluid cannot escape from the pressure equalizing hole 30a to the low-pressure flow path 30L, so that the upper side X1 outside the main valve 3 becomes high pressure, and the main valve 3 is pressed against the valve seat 20 due to the pressure difference between the upper side X1 of the main valve 3 and the low-pressure flow path 30L. This completes the switching operation of the valve ports 20D, 20S, 20C, and 20E by the main valve 3. In this manner, in the rotary switching valve 100 serving as a valve device, the rotation of the sub-valve 4, which is rotationally driven by the drive unit 5, is transmitted to the main valve 3, thereby switching the valve ports 20D, 20S, 20C, and 20E.

[0054] In this embodiment, as shown in FIG. 8(A), the initial state is the state in which the main valve 3 is in the first switching position. However, conversely, when the valve ports 20D, 20S, 20C, and 20E are switched from the state in which the main valve 3 is in the second switching position as shown in FIG. 8(B), the initial state is the state in which the main valve 3 is in the second switching position in which the low-pressure flow path 30L of the main valve 3 connects the C switching port 20C to the S port 20S, and the high-pressure flow path 30H connects the D port 20D to the E switching port 20E. Needless to say, by reversing the rotation direction of the worm 52 (i.e., the second direction) from the above explanation, the main valve 3 and the sub-valve 4 are rotated in a clockwise direction (not shown), which is opposite to the counterclockwise direction D1.

[0055] As shown in Fig. 3, when the main valve 3 is restricted from rotating (stopped from rotating) by the main valve stopper 9 and the sub-valve 4 is restricted from rotating by the sub-valve stopper 31a1, a second backlash S2 (axial backlash), which is a gap in the axial direction, is generated between the first step 52c (step) or the second step 52f (step) of the worm 52 and an end face of the inner ring 53a of the rotation support part 53 (between the second step 52f and an end face of one side A1 of the inner ring 53a of the rotation support part 53 arranged on the other side A2 of the two rotation support parts 53 in Fig. 4). Therefore, even when the main valve 3 is restricted from rotating by the main valve stopper 9, the worm 52 can be displaced in the radial direction Y by the above-mentioned first backlash S1 and can be displaced in the axial direction A by the second backlash S2.

[0056] Here, when the main valve 3 and the sub-valve 4 are rotated in either the counterclockwise direction D1 or the clockwise direction, a rotation signal may be sent to the electric motor 51 even when the rotation of the main valve 3 and the sub-valve 4 is stopped. This is because, as described above, even if the maximum rotation amount of the sub-valve 4 around the central axis 6 with respect to the valve body 1 is about 210° and theoretically the sub-valve 4 rotates the maximum rotation amount with 1400 pulses, 1400 pulses or more are applied to the electric motor 51 to ensure that the enlarged diameter portion 40a of the sub-valve 4 hits the sub-valve stopper 31a1.

[0057] That is, in the rotary switching valve 100, for example, backlash occurs at the meshing portion between the worm 52 and the worm wheel 54, and play occurs between the central shaft 6 and the main valve 3 and the auxiliary valve 4. Taking these play and other factors into consideration, in order to reliably rotate the auxiliary valve 4 the maximum amount of rotation to bring the main valve 3 into contact with the main valve stopper 9 and bring the auxiliary valve 4 into contact with the auxiliary valve stopper 31a1 of the main valve 3, a rotation signal of 1400 pulses + α (for example, 1500 pulses) is sent with a margin, so that the auxiliary valve 4 can be reliably rotated the maximum amount of rotation.

[0058] In this case, since the worm 52 continues to rotate while the rotation of the sub-valve 4 is stopped, i.e., while the rotation of the worm wheel 54 is restricted, a force (thrust force) in the direction of the axis A is applied to the worm 52, as shown by the arrow toward the other side A2 in Fig. 5, and the worm 52 tries to move in the same direction. At this time, as shown in Fig. 4, in this embodiment, the second backlash S2 is provided between the second step portion 52f and the end face of the inner ring 53a of the rotation support portion 53, so that the worm 52 can move in the direction of the axis A.

[0059] Then, the worm 52 that has moved in this manner comes into contact with the end face of the inner ring 53a, as shown in Fig. 5, so that its movement in the direction of the axis A is restricted, but if a rotational force is further applied to the worm 52, the worm 52 will slide toward the meshing portion with the worm wheel 54, as shown by the arrow pointing in the radial direction Y in Fig. 5. At this time, in a conventional configuration in which the worm 52 comes into contact with the worm support portion, a reaction force is generated between the meshing portion and the end face of the inner ring 53a, which causes the worm 52 to brace, and frictional forces are generated at the meshing portion and the worm support portion, resulting in a phenomenon known as worm lock, in which the worm 52 cannot rotate in the reverse direction.

[0060] However, in this embodiment, the worm 52 can rotate about the axis A via the rolling members 53c even after it comes into contact with the inner ring 53a. Also, the worm 52 can be displaced in the radial direction Y and slide along the inner peripheral surface of the inner ring 53a by the amount of the first backlash S1 described above. This prevents the worm 52 from slipping into the meshing portion as described above, thereby preventing worm lock. In this way, the rotation support portion 53 (bearing) has a lock prevention mechanism that prevents the worm 52 from locking.

[0061] Next, a refrigeration cycle system using the rotary switching valve 100 as a flow path switching valve will be described. Figures 8(A) and (B) are diagrams showing a refrigeration cycle system of an embodiment, which is an example of a refrigeration cycle system of an air conditioner. The air conditioner has a compressor P, an outdoor heat exchanger 60 (condenser or evaporator), an expansion valve 70, an indoor heat exchanger 80 (condenser or evaporator), and the rotary switching valve 100 as a flow path switching valve, and each of these elements is connected by a conduit as shown in the figure to constitute a heat pump type refrigeration cycle system.

[0062] The flow path of the refrigeration cycle system can be switched between two flow paths for cooling operation and heating operation by rotating the main valve 3 of the rotary switching valve 100 as described above. During cooling operation in FIG. 8(A), the S port 20S is connected to the E switching port 20E by the low pressure flow path 30L of the main valve 3 in the rotary switching valve 100, and the D port 20D is connected to the C switching port 20C by the high pressure flow path 30H. Then, as shown by the arrows in the figure, the refrigerant as a fluid compressed by the compressor P flows into the D port 20D of the rotary switching valve 100 and flows into the outdoor heat exchanger 60 from the C switching port 20C, and the refrigerant flowing out of the outdoor heat exchanger 60 flows into the expansion valve 70. Then, the refrigerant is expanded by this expansion valve 70 and supplied to the indoor heat exchanger 80. The refrigerant flowing out from the indoor heat exchanger 80 flows from the E switching port 20E to the S port 20S in the rotary switching valve 100, and is circulated to the compressor P from the S port 20S.

[0063] During heating operation in FIG. 8(B), in the rotary switching valve 100, the S port 20S is connected to the C switching port 20C by the low pressure flow path 30L of the main valve 3, and the D port 20D is connected to the E switching port 20E by the high pressure flow path 30H. Then, as shown by the arrows in the figure, the refrigerant compressed by the compressor P flows into the D port 20D of the rotary switching valve 100 and flows into the indoor heat exchanger 80 from the E switching port 20E, and the refrigerant flowing out from the indoor heat exchanger 80 flows into the expansion valve 70. Then, the refrigerant is expanded by this expansion valve 70 and supplied to the outdoor heat exchanger 60. The refrigerant flowing out from the outdoor heat exchanger 60 flows from the C switching port 20C to the S port 20S in the rotary switching valve 100, and is circulated from the S port 20S to the compressor P.

[0064] As described above, according to this embodiment, the worm 52 is supported by the rotation support part 53 having a lock prevention mechanism so as to be rotatable around the axis A (around the axis) and movable in the direction of the axis A (axial direction). Therefore, when the rotation of the electric motor 51 (electric motor) is continued by a rotation signal in the same rotation direction after the rotation of the main valve 3 (valve body) is stopped, even if the worm 52 moves in the direction of the axis A and abuts against the rotation support part 53, the worm 52 prevented from locking rotates around the axis A, etc., thereby reducing the tension of the worm 52, the frictional force of the meshing part between the worm 52 and the worm wheel 54, and the frictional force between the worm 52 and the rotation support part 53. Therefore, by reducing the friction between the worm 52 and the part supporting the worm 52, it is possible to obtain a rotary type switching valve 100 (valve device) that can prevent worm lock and improve the stability of the switching operation of the valve ports 20D, 20S, 20C, and 20E by the main valve 3 (valve body).

[0065] Furthermore, since the rotation support portion 53 is formed of a bearing, this bearing forms a lock prevention mechanism, thereby preventing the above-mentioned worm lock and restricting the movement of the worm 52 in the direction of the axis A with the end face of this bearing.

[0066] Furthermore, when the electric motor 51 continues to rotate in response to a rotation signal in the same rotation direction after the main valve 3 stops rotating, even if the worm 52 moves in the thrust direction, which is the direction of the axis A, and comes into contact with the end face of the rotation support part 53, the worm 52 can be displaced by the first backlash S1 (backlash in the radial direction Y) or slide along the inner diameter of the rotation support part 53. This prevents the worm 52 from being strained between the meshing part and the rotation support part 53 due to the displacement or sliding of the worm 52, and reduces the frictional force generated in the meshing part or the rotation support part 53.

[0067] In addition, when the main valve 3 (valve body) is stopped from rotating, a second backlash S2 (axial backlash) is provided between the first step 52c (step) or the second step 52f (step) of the worm 52 and the end face (end face of the bearing) of the inner ring 53a of the rotation support part 53. Therefore, when the electric motor 51 continues to rotate by a rotation signal in the same rotation direction after the main valve 3 stops rotating, the worm 52 can move in the direction of the axis A. In addition, when the worm 52 moves in the direction of the axis A and abuts against the rotation support part 53, the worm 52 can be rotated in the reverse direction to move only the worm 52 by the amount of the second backlash S2. This reduces the frictional force generated in the meshing part, making it easier to prevent worm lock.

[0068] Furthermore, since the rotation support portion 53 can be a bearing constituted by a ball bearing (bearing) having an inner ring 53a, an outer ring 53b, and a rolling member 53c, the bearing constituted by this ball bearing can prevent worm lock.

[0069] In addition, since the worm 52 can be supported by the rotational support parts 53 arranged on one side A1 and the other side A2 of the worm 52, the worm 52 can be prevented from swinging in a direction intersecting the direction of the axis A by the rotational support parts 53 arranged on both ends of the worm 52 in the direction of the axis A.

[0070] In addition, as described above, by providing the first backlash S1 and the second backlash S2, when assembling the rotary switching valve 100 by inserting the worm 52 into the rotation support portion 53, the assembly can be made easier compared to a configuration without such backlash.

[0071] Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and even if the design is changed within the scope of the present invention, the present invention is included. FIG. 6 is a diagram showing the rotation support portion 53 in a first modified example. This modified example differs from the present embodiment in that the above-mentioned rotation support portion 53 is configured with a cylindrical bush 57. That is, the rotation support portion 53 in the above-mentioned embodiment is configured with a ball bearing, i.e., a rolling bearing, but in the first modified example, the rotation support portion 53 is configured with a sliding bearing. The bush 57 is formed of a material with low sliding resistance (low friction coefficient), and is disposed on one side A1 and the other side A2 of the worm 52. Specific materials for the bush 57 include sintered metal containing a solid lubricant, high-strength resin material, or a metal material coated with a coating agent with a low friction coefficient. A first backlash S1 is provided between the inner circumferential surface of the bush 57 and the first reduced diameter portion 52b and the second reduced diameter portion 52g of the worm 52, as in the present embodiment. In addition, in a state in which the rotation of the main valve 3 is restricted by the main valve stopper 9 and the rotation of the sub-valve 4 is restricted by the sub-valve stopper 31a1, a second backlash S2 (axial backlash), which is a gap in the direction of the axis A, is generated between the first step 52c (step) or the second step 52f (step) of the worm 52 and the end face of the bush 57 (in FIG. 6, between the second step 52f and the end face of the one side A1 of the bush 57 arranged on the other side A2 of the two bushes 57). With this configuration, as in the present embodiment, it is possible to obtain a rotary switching valve 100 (valve device) that can prevent worm lock by reducing friction between the worm 52 and the part that supports the worm 52, thereby improving the stability of the switching operation of the main valve 3 (valve body) of the valve ports 20D, 20S, 20C, and 20E.

[0072] FIG. 7 is a diagram showing the drive unit 5 and the worm 52 in the second modified example. The second modified example differs from the above-described embodiment and the first modified example in that the biasing force of the first coil spring 55 (indicated by an arrow pointing to the one side A1 in FIG. 7) is set to be greater than the thrust force (indicated by an arrow pointing to the other side A2 in FIG. 7) acting on the worm 52 toward the other side A2 of the worm 52 due to the meshing between the worm 52 and the worm wheel 54. With this configuration, even if the electric motor 51 continues to rotate by a rotation signal in the same rotation direction after the rotation of the main valve 3 stops, and the worm 52 tries to move, for example, to the other side A2, the movement can be suppressed by the first coil spring 55 having a biasing force greater than the thrust force acting on the worm 52 toward the other side A2. In this case, the main function of the rotation support part 53 provided on the other side A2 of the two rotation support parts 53 is to prevent the worm 52 from swinging in a direction intersecting the axis A direction, and therefore, from the viewpoint of preventing worm lock, it may be omitted.

[0073] In the above-mentioned embodiment and modified example, the valve device has been described as the rotary switching valve 100, but the valve device may be other than the rotary switching valve 100. For example, the present invention can be applied to an electric flow control valve in which a valve body driven by an electric motor and a worm gear is moved in the axial direction (i.e., vertical direction) of a central axis perpendicular to a valve seat surface relative to the valve seat surface to open and close a valve port, and the rotation of the valve body is stopped by a stopper provided on the valve body. Similarly, the present invention can be applied to a flow path opening and closing valve of an electric ball valve in which each flow path is switched by rotating a ball valve having a plurality of flow paths opening in the radial direction of the central axis in the horizontal direction. Similarly, the present invention can be applied to an electric rotary expansion valve that includes a valve seat plate having a groove portion whose groove width gradually changes and a valve body having a slit aligned with the groove portion, and controls the throttle flow rate according to the rotational displacement of the valve body around the central axis.

[0074] In addition, in this embodiment, a ball bearing, in particular a ball bearing, is used as the rotation support part 53. However, the rotation support part 53 is not limited to a ball bearing, and a bearing such as a roller bearing in which the rolling member 53c is a roller-shaped member may be used.

[0075] In addition, in this embodiment, the rotary type switching valve 100 in which the rotation of the main valve 3 is restricted by the main valve stopper 9 has been described, but the part that restricts the rotation of the main valve 3 is not necessarily limited to the main valve stopper 9. For example, the present invention can also be applied to a rotary type switching valve 100 configured such that a stopper protruding from the ceiling part of the valve body 1 to the lower side X2 is provided, and a stopper protruding from the upper surface of the worm wheel 54 to the upper side X1 is provided, and the rotation of the worm wheel 54 is restricted by abutting these stoppers against each other, thereby restricting the rotation of the sub-valve 4, and thereby restricting the rotation of the main valve 3. [Explanation of symbols]

[0076] 1 Valve body 3 Main valve (valve body) 5 Drive unit 9 Main valve stopper (stopper) 51 Electric motor 52 Warm 53 Rotation support part 54 Worm Wheel 100 Rotary switching valve (valve device)

Claims

1. A valve device comprising a valve body, a valve element, and a drive unit, the valve element being rotationally driven by the drive unit and the valve element being stopped from rotating by a stopper of the valve body, The drive unit includes a worm rotated by an electric motor and a worm wheel meshed with the worm, The worm is supported by at least one rotation support portion so as to be rotatable about an axis and movable in an axial direction, the rotation support portion has a lock prevention mechanism that prevents the worm from locking, the lock prevention mechanism is constituted by an annular bearing provided in the rotation support portion, The worm has a reduced diameter portion that is inserted into the bearing and a step portion that extends radially outward from the reduced diameter portion, When the rotation of the valve body is stopped, a play in the axial direction is provided between the step portion and an end face of the bearing, The step portion moves to the axially adjacent side approaching the end face of the bearing and abuts against the end face of the bearing, thereby restricting the movement of the worm to the axially adjacent side, The valve device according to claim 1, wherein the worm is supported by the bearing so as to be rotatable about its axis when the step is in contact with an end face of the bearing.

2. 2. The valve device according to claim 1, wherein a radial play is provided between the worm and an inner diameter of the bearing.

3. The bearing includes an inner ring, an outer ring, and a rolling member, the end surface of the bearing is an end surface of the inner ring, The valve device according to claim 1, wherein the step portion abuts against an end face of the inner ring, thereby restricting movement of the worm toward the adjacent side in the axial direction.

4. 2. The valve device according to claim 1, wherein the bearing is a bush made of a material having low sliding resistance and formed into a cylindrical shape.

5. A valve device comprising a valve body, a valve element, and a drive unit, the valve element being rotationally driven by the drive unit and the valve element being stopped from rotating by a stopper of the valve body, The drive unit includes a worm rotated by an electric motor and a worm wheel meshed with the worm, The worm is supported by at least one rotation support portion so as to be rotatable about an axis and movable in an axial direction, the rotation support portion has a lock prevention mechanism that prevents the worm from locking, the rotation support portion is disposed on one side of the worm in an axial direction, the side being where the electric motor is located; The drive portion includes a biasing member that biases the worm toward one side in the axial direction, The valve device according to claim 1, wherein the biasing force of the biasing member is greater than a thrust force, which is an axial force acting on the worm toward the other axial side of the worm due to engagement with the worm wheel.

6. 6. The valve device according to claim 5, wherein the rotation support portion is also disposed on the other axial side of the worm.

7. a valve chamber provided inside the valve body, a valve seat portion having a plurality of valve ports opening into the valve chamber, a main valve provided inside the valve body rotatably about a central axis intersecting the valve seat portion, and an auxiliary valve provided rotatably about the central axis for opening and closing a pressure equalizing hole of the main valve, A rotary switching valve as a valve device described in any one of claims 1 to 6, characterized in that the rotation of the sub-valve, which is rotationally driven by the drive unit, is transmitted to the main valve, thereby switching the valve port.

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