Rotary valve

Abstract

The present application provides a rotary valve capable of reducing the number of components. The rotary valve includes a motor, a rotor shaft that is axially rotated by the motor, a housing that houses the rotor shaft in an internal space, a stator that is fixed to the housing on a top end side of the rotor shaft, a rotor that is held at the top end of the rotor shaft and rotates together with the rotor shaft, a bearing that is interposed between an inner peripheral surface of the housing and an outer peripheral surface of the rotor shaft, and supports the rotor shaft while engaging with the rotor shaft in an axial direction of the rotor shaft, and an elastic member that is provided in the internal space of the housing so as to apply a force to the rotor shaft toward a side of the stator via the bearing while being independent of rotation of the rotor shaft.

Description

Technical Field

[0001] This invention relates to a rotary flow path switching valve (hereinafter referred to as a rotary valve) used in analytical devices such as liquid chromatographs, and more particularly to a rotary valve. Background Technology

[0002] In analytical devices such as liquid chromatographs, rotary valves are widely used as valves for switching flow path connections. In a rotary valve, the rotor is held at the top of a rotor shaft that is rotated by a motor, and the rotor shaft is pressed towards the stator side by the elastic force of elastic components such as helical springs, thereby pressing the rotor against the stator to ensure surface pressure, thus obtaining high pressure resistance (see Patent Document 1).

[0003] [Existing technical documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] International Patent Publication No. 2019 / 188011 Summary of the Invention

[0006] [The technical problem that the invention aims to solve]

[0007] In rotary valves, the elastic component that applies force to the rotor towards the stator is typically configured to rotate together with the rotor shaft. To ensure smooth rotation of the rotor shaft, multiple bearings are often used, including radial bearings supporting the rotor shaft and thrust bearings supporting the elastic component. However, the bearings themselves have complex shapes and require precision, and interference components such as spacers are also needed, leading to an increase in the number of components. This increase in the number of components not only leads to larger product dimensions and higher manufacturing costs, but also causes dimensional tolerances to accumulate, potentially deteriorating the rotor's positional accuracy. If the rotor's positional accuracy deteriorates, the grooves in the rotor will shift from the holes in the stator, resulting in an increase in dead volume and the formation of residues or diffusion, adversely affecting the analytical results.

[0008] The present invention was made in view of the above-mentioned problems, and its purpose is to reduce the number of components in a rotary valve.

[0009] [The technical solution adopted to solve the technical problem]

[0010] The rotary valve of the present invention includes: a motor; a rotor shaft that is axially rotated by the motor; a housing that houses the rotor shaft in an internal space; a stator that is fixed to the housing at the top end of the rotor shaft; a rotor that is held at the top end of the rotor shaft and rotates with the rotor shaft; a bearing that is located between the inner circumferential surface of the housing and the outer circumferential surface of the rotor shaft, supporting the rotor shaft and engaging axially with respect to the rotor shaft; and an elastic member disposed in the internal space of the housing to apply a force to the rotor shaft toward the stator via the bearing while the rotor shaft rotates independently of the rotor shaft.

[0011] [Invention Effects]

[0012] According to the rotary valve of the present invention, a bearing supporting the rotor shaft is located between the inner circumferential surface of the housing and the outer circumferential surface of the rotor shaft, engages axially with respect to the rotor shaft, and an elastic member is provided so that the rotor shaft is forcefully directed toward the stator side via the bearing while rotating independently of the rotor shaft. Therefore, the elastic member does not rotate with the rotation of the rotor shaft, and a bearing supporting the elastic member is not required. Thus, the bearing used to achieve smooth rotation of the rotor shaft can be reduced to one, thereby reducing the number of components in the rotary valve. Attached Figure Description

[0013] Figure 1 This is a partial cross-sectional view showing one embodiment of a rotary valve.

[0014] Figure 2 This is a partial cross-sectional view showing the state after the motor has been removed in the same embodiment.

[0015] Explanation of icon numbers

[0016] 1: Rotary valve

[0017] 2: Shell

[0018] 4: Stator

[0019] 6: Motor

[0020] 8: Rotor shaft

[0021] 10: Rotor

[0022] 12: Bearings

[0023] 14: Elastic components

[0024] 16: Protrusion

[0025] 18: Internal space of the shell

[0026] 20: Piping connection

[0027] 22: Outer ring of the bearing

[0028] 24: Inner ring of the bearing

[0029] 26: Concave

[0030] 28: Drive shaft

[0031] 30: Sales

[0032] 32: Trench

[0033] 34: Buckle

[0034] 36: Mounting plate

[0035] 38: Rotation sensor Detailed Implementation

[0036] Hereinafter, an embodiment of the rotary valve involved in the present invention will be described with reference to the accompanying drawings.

[0037] like Figure 1 As shown, the rotary valve 1 mainly includes: housing 2, stator 4, motor 6, rotor shaft 8, rotor 10, bearing 12, and elastic component 14.

[0038] The housing 2 is a generally hollow cylindrical, one-piece component with an opening at the top (upper end in the figure). The stator 4 is fixed to the top of the housing 2 by bolts, and the motor 6 is fixed to the base of the housing 2 (lower end in the figure) by bolts. That is, the stator 4 and the motor 6 are fixed to a common single component (housing 2). Therefore, the rotary valve 1 has a structure that fixes the stator 4 and the motor 6 to a one-piece structure, namely the housing 2, thus reducing the number of parts and facilitating assembly.

[0039] The stator 4 is provided with multiple pipe connection parts 20 for connecting piping. Only one pipe connection part 20 is shown in the figure. The pipe connection part 20 communicates with the surface (lower side in the figure) of the internal space 18 of the housing 2 via a flow path. With the rotor 10 in contact with the lower side of the stator 4, the rotor 10 rotates, thereby switching the interconnection state of the multiple pipes connected to the stator 4.

[0040] The rotor shaft 8 is disposed within the internal space 18 of the housing 2, with its top end (upper end in the figure) facing the stator 4 and its base end (lower end in the figure) facing the motor 6. The rotor shaft 8 rotates axially via the motor 6. The rotor 10 is held at the top end of the rotor shaft 8 and rotates with the rotation of the rotor shaft 8.

[0041] Bearing 12 is located between the outer circumferential surface of rotor shaft 8 and the inner circumferential surface of housing 2, supporting rotor shaft 8 to ensure stable rotation. In the embodiment described, bearing 12 is a ball bearing having an outer ring 22 and an inner ring 24. The outer ring 22 of bearing 12 has an outer diameter slightly smaller than the inner diameter of housing 2, and the inner ring 24 of bearing 12 has an inner diameter slightly larger than the outer diameter of rotor shaft 8. Furthermore, bearing 12 does not necessarily have to be a ball bearing; it can also be a sliding bearing.

[0042] The top end of the rotor shaft 8 is provided with a protrusion 16 that protrudes radially outward from the outer peripheral surface. In the embodiment described, the protrusion 16 is constituted by a C-shaped retaining ring installed in a groove provided on the outer peripheral surface of the rotor shaft 8. On the other hand, the present invention is not limited to this, and the protrusion 16 may also be integrally formed with the rotor shaft 8. Furthermore, when the protrusion 16 is integrally formed with the rotor shaft 8, it is necessary to perform machining on the rod to form the protrusion 16 and then perform a grinding process. However, if the protrusion 16 is realized by using a retaining ring, the rotor shaft 8 can be manufactured simply by groove machining on the pre-ground rod (the rod-shaped component before being machined into the rotor shaft 8) and then inserting the retaining ring, thereby reducing costs.

[0043] The bearing 12 is positioned closer to the base end of the rotor shaft 8 than the protrusion 16, and the inner ring 24 of the bearing 12 engages with the protrusion 16. That is, relative to the rotor shaft 8, the bearing 12 engages only in the axial direction (upper direction in the figure) of the rotor shaft 8.

[0044] The elastic member 14 is disposed in a compressed state within the internal space 18 of the housing 2, closer to the base end of the rotor shaft 8 than the bearing 12, so as to apply force to the bearing 12 toward the stator 4. By applying force to the bearing 12 toward the stator 4 through the elastic member 14, the rotor shaft 8, which engages with the bearing 12 and the protrusion 16, is also forced toward the stator 4, pressing the rotor 10, held at the top of the rotor shaft 8, against the stator 4. This ensures a seal between the stator 4 and the rotor 10. Furthermore, in this embodiment, the rotor 10 is configured to directly contact the stator 4, but the invention is not limited to this; other components fixed to the stator 4 may also be present between the stator 4 and the rotor 10.

[0045] The elastic member 14 is in direct contact with the outer ring 22 of the bearing 12 only. In other words, the elastic member 14 contacts the bearing 12 without interfering with the inner ring 22 of the bearing 12, and the elastic member 14 does not rotate with the rotation of the rotor shaft 8. Therefore, a thrust bearing is not required to support the elastic member 14 and allow it to rotate smoothly. Thus, the only component that interferes with the rotation of the rotor shaft 8 is the inner ring 24 of the bearing 12, and therefore, components such as bearings are not required to allow smooth rotation of components other than the rotor shaft 8, which helps to reduce the number of components in the rotary valve 1.

[0046] Furthermore, in the embodiment described above, the elastic member 14 is a helical spring having an outer diameter that only contacts the outer ring 22 of the bearing 12. However, the present invention is not limited to this. Any component capable of applying force to the bearing 12, such as a leaf spring, can be used as the elastic member 14.

[0047] Furthermore, the elastic member 14 does not necessarily have to be in direct contact with the outer ring 22 of the bearing 12. It can also be configured such that the elastic member 14 applies force toward the stator 4 by means of a member that contacts the outer ring 22 without interfering with the inner ring 24 of the bearing 12.

[0048] The above describes the case where bearing 12 is a ball bearing. However, when bearing 12 is a sliding bearing, bearing 12 itself will not rotate with the rotation of rotor shaft 8. Therefore, the elastic component 14 in contact with bearing 12 will not rotate. Similar to the case of ball bearing, there is no need for a thrust bearing to support the elastic component 14 and make it rotate smoothly.

[0049] The motor 6 is fixed to the integral housing 2, and the central axis of the drive shaft 28 of the motor 6 coincides with the central axis of the rotor shaft 8. The top end of the drive shaft 28 of the motor 6 and the base end of the rotor shaft 8 are provided with a mating structure, through which the drive shaft 28 of the motor 6 and the rotor shaft 8 mesh only in the rotational direction. In this embodiment, the mating structure consists of a pin 30 mounted on the top end of the drive shaft 28 of the motor 6, and a recess 26 and a groove 32 provided on the base end of the rotor shaft 8. The pin 30 passes through the drive shaft 28 in a direction perpendicular to the axial direction (left-right direction in the figure). The top end of the drive shaft 28 of the motor 6 is inserted into the recess 26 at the base end of the rotor shaft 8, and the pin 30 mounted on the drive shaft 28 is fitted into the groove 32. The width of the groove 32 is approximately the same as the outer diameter of the pin 30. Thus, when the drive shaft 28 of the motor 6 rotates, the pin 30 pushes the inner side of the groove 32 at the base end of the rotor shaft 8, causing the rotor shaft 8 to rotate.

[0050] Furthermore, the mating structure is not limited to the structures described above; any structure that allows the drive shaft 28 and the rotor shaft 8 to mesh only in the rotational direction can be used. For example, the top end of the drive shaft 28 of the motor 6 can be in the shape of a gear, and the recess 26 of the rotor shaft 8 can be in a shape that mates with the top end of the drive shaft 28. As described above, the drive shaft 28 and the rotor shaft 8 of the motor 6 mesh only in the rotational direction through the mating structure, which is simple in structure and therefore eliminates the need for components such as couplings to connect the drive shaft 28 and the rotor shaft 8, thus helping to reduce the number of components.

[0051] In addition, such as Figure 2As shown, the structure is such that the drive shaft 28 and rotor shaft 8 of the motor 6 do not interfere with each other axially. If the stator 4 is removed from the housing 2 while the motor 6 is fixed to it, the rotor shaft 8 will be pushed in the opposite direction (upper direction in the figure) due to the elastic force of the elastic member 14, thus applying a load to the drive shaft 28 and potentially affecting the performance of the motor 6. In this embodiment, since the drive shaft 28 and rotor shaft 8 of the motor 6 do not interfere with each other axially, even if the stator 4 is removed from the housing 2, no load will be applied to the drive shaft 28 of the motor 6.

[0052] In the embodiment, a retaining ring 34 for preventing detachment is installed on the outer peripheral surface of the base end of the rotor shaft 8, so as to prevent the rotor shaft 8 from being ejected toward the side opposite to the motor 6 due to the elastic force of the elastic member 14 when the stator 4 is removed from the housing 2.

[0053] A rotation sensor 38 for detecting the rotational position of the drive shaft 28 of the motor 6 is mounted on the housing 2 via a mounting plate 36. This eliminates the need for a separate mechanism for detecting the rotational position of the drive shaft 28 of the motor 6 outside the housing 2, thus reducing the number of components.

[0054] The embodiments described above are merely one example of the implementation of the rotary valve involved in this invention. The implementation of the rotary valve involved in this invention is as follows.

[0055] One embodiment of the rotary valve of the present invention includes: a motor; a rotor shaft that is axially rotated by the motor; a housing that houses the rotor shaft in an internal space; a stator fixed to the housing at the top end of the rotor shaft; a rotor held at the top end of the rotor shaft and rotating together with the rotor shaft; a bearing located between the inner circumferential surface of the housing and the outer circumferential surface of the rotor shaft, supporting the rotor shaft while engaging axially with respect to the rotor shaft; and an elastic member disposed in the internal space of the housing to apply force to the rotor shaft toward the stator via the bearing while the rotor shaft rotates independently of the rotor shaft.

[0056] In a first aspect of one of the above embodiments, the bearing is a ball bearing having an inner ring and an outer ring, the inner ring of the ball bearing meshing with the rotor shaft axially along the rotor shaft, and the elastic member being configured to directly contact only the outer ring relative to the ball bearing to apply a force to the ball bearing toward the stator.

[0057] In a second embodiment of the above-described method, the rotor shaft has a protrusion at its top end that projects radially outward from its outer peripheral surface, and the bearing engages with the rotor shaft by contacting the protrusion. This second embodiment can be combined with the first embodiment described above.

[0058] In a third embodiment described above, the protrusion is a retaining ring mounted on the outer circumferential surface of the rotor shaft. This third embodiment can be combined with the first and / or second embodiments described above.

[0059] In the fourth embodiment described above, the housing is a one-piece structure, and both the motor and the stator are fixed to the housing. This fourth embodiment can be combined with the first, second, and / or third embodiments described above.

[0060] In the fourth method described above, the central axis of the motor's drive shaft and the central axis of the rotor shaft can be aligned with each other.

[0061] In the above-described manner, the top end of the drive shaft of the motor and the base end of the rotor shaft may be provided with a mating structure that engages with each other in the rotational direction through mutual cooperation. The drive shaft and the rotor shaft of the motor can engage with each other only in the rotational direction through this mating structure.

[0062] Furthermore, in the above-described case, the mating structure may include: a pin, perpendicular to the axial direction and passing through the top end of the drive shaft of the motor; and a groove, provided on the base end of the rotor shaft, for the pin to be inserted.

Claims

1. A rotary valve, characterized in that, include: Electric motor; The rotor shaft rotates axially via the motor; The housing encloses the rotor shaft within its internal space; The stator is fixed to the housing at the top end of the rotor shaft; The rotor is held at the top of the rotor shaft and rotates together with the rotor shaft; A bearing, located between the inner circumferential surface of the housing and the outer circumferential surface of the rotor shaft, supports the rotor shaft while engaging with it axially along the rotor shaft. as well as An elastic member is disposed in the internal space of the housing so as to apply a force to the rotor shaft toward the stator via the bearing while the rotor shaft rotates independently of the rotor shaft.

2. The rotary valve according to claim 1, characterized in that, The bearing is a ball bearing with an inner ring and an outer ring. The inner ring of the ball bearing meshes with the rotor shaft axially along the rotor shaft. The elastic member is configured to make direct contact with the outer ring only relative to the ball bearing, so as to apply a force to the ball bearing toward the stator.

3. The rotary valve according to claim 1, characterized in that, The rotor shaft has a protrusion at its top end that projects radially outward from its outer peripheral surface. The bearing engages with the rotor shaft by contacting the protrusion.

4. The rotary valve according to claim 3, characterized in that, The protrusion is a retaining ring mounted on the outer circumferential surface of the rotor shaft.

5. The rotary valve according to claim 1, characterized in that, The shell is a one-piece structure. Both the motor and the stator are fixed to the housing.

6. The rotary valve according to claim 5, characterized in that, The central axis of the motor's drive shaft coincides with the central axis of the rotor shaft.

7. The rotary valve according to claim 6, characterized in that, The top end of the drive shaft of the motor and the base end of the rotor shaft are provided with a mating structure that engages with each other in the rotational direction. The drive shaft and the rotor shaft of the motor mesh with each other only in the rotational direction through the mating structure.

8. The rotary valve according to claim 7, characterized in that, The mating structure includes: A pin, perpendicular to the axial direction and passing through the top end of the drive shaft of the motor; and A groove is provided on the base end of the rotor shaft for the pin to be inserted.

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