JP2016160772A - Roots pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved structure of a Roots pump in which a resistance of fluid within a casing at such a Roots pump is effectively reduced and the flow can be made smooth.SOLUTION: An inlet 24 is arranged at a casing 10 [10a, 10b] so as to be positioned between rotary shafts 34 of a pair of rotors 20, 20, and inlet flow regulating means 30 [inlet side protrusions 30a, 30b] is arranged at the side of the inlet 24 of a space formed between each of the pair of rotors 20, 20 and the inner circumferential surface of a rotor chamber 22 in the casing 10 so that the fluid fed from the inlet 24 is divided by the inlet flow regulating means 30, and the fluid is fed into each of spaces formed between each of the pair of rotors 20, 20 and the inner circumferential surface of the rotor chamber 22 of the casing 10, respectively.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a roots-type pump, and more particularly to an improvement of a roots-type pump that can exert a pump action by a pair of rotors that mesh with each other and are rotated in opposite directions.

  Conventionally, pumps such as reciprocating pumps, rotary pumps, centrifugal pumps, propeller pumps, jet pumps, etc. have been used as devices for transporting fluids such as gases and liquids. As one example, a roots type pump is known. This Roots type pump includes, for example, a casing having a suction port and a discharge port and having a rotor chamber inside as disclosed in Japanese Patent Application Laid-Open Nos. 2000-179482 and 2-218882. And a pair of rotors housed in such a rotor chamber so that the rotation axes are parallel to each other and meshed with each other and rotated in opposite directions, and exhibit pumping action as the rotors rotate, The fluid introduced into the rotor chamber from the suction port is discharged from the discharge port.

  By the way, in such a conventional Roots type pump, for example, as schematically shown in FIG. 6, a pair of rotors 66a and 66b accommodated in a rotor chamber 64 of a housing 62 are engaged with each other and reversed. The fluid is introduced into the rotor chamber 64 through the suction port 68 and discharged through the discharge port 70 by the pump action caused by being rotated in the direction. The discharge port 70 is provided so as to be positioned between the rotation shafts 67a and 67b of the pair of rotors 66a and 66b, so that the fluid is introduced from the suction port 68 and discharged to the outside through the discharge port 70. It has become.

  However, in the Roots-type pump having such a configuration, the fluid introduced through the suction port 68 is formed between each of the pair of rotors 66a and 66b and the inner peripheral surface of the rotor chamber 64 of the casing 62. In the form housed in the space, after being guided to the discharge port 70 side by the rotation of the rotors 66a and 66b, the pair of rotors is connected through the suction port 68 from the outside through the discharge port 70. The fluid introduced into the meshing portions of 66a and 66b is bent 90 ° left and right and moved along the inner peripheral surface of the rotor chamber 64, and then collided from the left and right at the site where the discharge port 70 is formed. The flow direction is then changed by 90 ° and discharged to the outside through the discharge port 70. In the casing 62, in other words, in the rotor chamber 64, the resistance to the fluid flow increases, and the pump efficiency is not sufficient.

JP 2000-179482 A JP-A-2-218882

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to provide an improved structure of the Roots type pump, and to be another problem. However, an object of the present invention is to provide a structure that can effectively reduce the resistance of the fluid in the casing in such a Roots type pump and can smoothly perform the flow.

  And, in order to solve the above-mentioned problems or the problems grasped from the description of the entire specification and the drawings, the present invention can be suitably implemented in various correspondences listed below. Each aspect described below can be employed in any combination. It should be noted that the aspects or technical features of the present invention are not limited to those described below, and can be recognized based on the description of the entire specification and the inventive concept disclosed in the drawings. Should be understood.

(1) A casing having a suction port and a discharge port, the inside of which is a rotor chamber, and the rotor chamber housed in such a manner that their rotation axes are parallel to each other. A roots-type pump having a pair of rotors to be squeezed and discharging fluid introduced into the rotor chamber from the suction port as the rotor rotates, from the discharge port; While being provided in the casing so as to be positioned between the rotation shafts of the pair of rotors, the fluid introduced from the suction port is divided, and between each of the pair of rotors and the rotor inner circumferential surface of the casing. A roots-type pump characterized in that an inlet side rectifying means for guiding the divided fluids to the formed space is disposed at the inlet side portion in the casing.
(2) The Roots pump according to the aspect (1), wherein the suction port is connected with a smooth curved surface to the rotor chamber inner circumferential surface of the casing.
(3) The aspect (1) or the aspect (2), wherein the inlet-side rectifying means has a triangular cross-sectional shape and is arranged so that the apex angle is located on the suction port side. Roots type pump.
(4) The discharge port is disposed with respect to the casing so as to face the suction port, and is formed between each of the pair of rotors and a rotor inner circumferential surface of the casing. Any one of the aspects (1) to (3), wherein the outlet side rectifying means for guiding the fluid discharged from the space to the discharge port is disposed at the discharge port side portion in the casing. Roots type pump described in 1.
(5) The Roots-type pump according to the aspect (4), wherein the discharge port is connected with a smooth curved surface with respect to the rotor chamber inner circumferential surface of the casing.
(6) The aspect (4) or the aspect (5), wherein the outlet side rectifying means has a triangular cross-sectional shape and is arranged so that the apex angle is located on the discharge port side. Roots type pump.
(7) The Roots pump according to any one of the aspects (1) to (6), wherein the rotor has a trilobal shape.
(8) The aspect in which the timing gears are respectively provided on the rotation shafts of the pair of rotors, and the pair of rotors are interlocked and rotated in opposite directions by the engagement of the timing gears ( The roots-type pump according to any one of 1) to aspect (7).
(9) The Roots pump according to the aspect (8), wherein the timing gear is disposed in the housing.
(10) Any of the above aspects (1) to (9), wherein a rotation driving means is attached to at least one of the rotation shafts, and the at least one rotation shaft is driven to rotate by the rotation driving means. Roots type pump as described in one.

  Thus, in the Roots-type pump according to the present invention, the inlet-side rectifying means for dividing the fluid introduced from the suction port is disposed on the suction-port side portion in the casing, so that the pair of rotors The flow direction of the fluid introduced from the suction port is changed to the right and left direction from the point where each of the divided fluids is guided to the space formed between each and the rotor inner circumferential surface of the casing. Therefore, an increase in fluid flow resistance can be effectively suppressed or prevented, and an efficient pump can be advantageously realized.

  Further, in the present invention, the fluid discharged from the space formed between each of the pair of rotors and the rotor chamber inner peripheral surface of the casing is also discharged at the discharge port side portion in the casing. By providing the outlet side rectifying means that leads to the outlet, the resistance of the flow of the fluid that is merged at the discharge port side portion in the casing can be effectively reduced, whereby the entire roots type pump can be reduced. As a result, the resistance of the fluid flow can be effectively reduced, and a very efficient roots-side pump can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is whole explanatory drawing which shows an example of the roots type pump according to this invention, Comprising: (a) is front explanatory drawing, (b) is back explanatory drawing, (c) is right side explanatory drawing. . It is AA cross-section enlarged explanatory drawing in FIG.1 (c). FIG. 3 is a cross-sectional explanatory view taken along line BB in FIG. It is expansion explanatory drawing of the casing main body and casing cover which comprise the casing of the Roots type pump shown by FIG. 1, (a) is a perspective explanatory drawing which shows the internal shape of a casing main body, (b) It is a perspective explanatory view showing the internal shape of the casing lid. FIG. 2 is an enlarged explanatory view showing a rotor used in the Roots type pump shown in FIG. 1, wherein (a) is a front explanatory view of the rotor, and (b) is a plan explanatory view thereof; (c) is CC sectional explanatory drawing in (b). It is a schematic diagram which shows the structure of the conventional roots type pump.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, an example of a Roots type pump according to the present invention is shown in a front form, a back form, and a right side form in FIGS. In this case, reference numeral 10 denotes a casing of a Roots type pump, which has a box shape with a predetermined depth, which is extended so that corresponding portions of the elliptical major axis are separated from each other. In addition, a suction pipe 12 for introducing a predetermined fluid is attached to the extended one end, and the other extended end is provided in the casing 10. A discharge pipe 14 is attached to discharge fluid that has been pumped. The casing 10 is composed of a pair of casing halves 10a and 10b which are given by being folded in a plane parallel to the circular shape. Further, as apparent from FIGS. 1B and 1C, a pulley 16 is disposed on the back surface of the casing 10, and a rotary drive device such as a motor (not shown) is connected to the pulley 16. As a result, the pulley 16 is rotated, so that a later-described rotor disposed in the casing 10 can be rotated.

  2 and 3 show a configuration in which a pair of rotors 20 and 20 are arranged inside one half 10a of the casing 10, and FIG. 4 shows such a configuration. The inside form of a pair of halves 10a, 10b of the casing 10 is shown. Therein, internal cavities 22a and 22b communicating with the outside are provided inside the casing halves 10a and 10b, respectively, at their opposing extended ends, and the pair of casing halves 10a and 10b are provided. By overlapping, the rotor chamber 22 is formed inside the casing 10 in the two internal cavities 22a and 22b. In addition, when the casing halves 10a and 10b are overlapped with each other at the communicating portions 24a and 24b; 26a and 26b to the outside at the corresponding both ends of the internal cavities 22a and 22b, The discharge ports 26 are respectively formed. Furthermore, as shown in FIGS. 2 and 4, the inner space 22 a that the inner surfaces of the communication portions 24 a, 24 b; 26 a, 26 b providing the suction port 24 and the discharge port 26 constitute the inner peripheral surface of the rotor chamber 22. , 22b, in other words, connected to the inner peripheral surface of the outer peripheral wall portion of each casing half 10a, 10b with a smooth curved surface.

  Furthermore, in the internal cavities 22a and 22b of the pair of casing halves 10a and 10b, an inlet side portion corresponding to the portion on the suction port 24 side and an outlet side portion corresponding to the portion on the discharge port 26 side, The entrance-side protrusions 30a and 30b and the exit-side protrusions 32a and 32b each having a substantially triangular planar shape are integrally formed at substantially the same height as the outer peripheral wall portion that defines the internal cavities 22a and 22b. Is provided. Specifically, as is clear from FIGS. 2 and 4, the inlet-side protrusions 30a and 30b are so positioned that the apex angle is located on the suction port 24 side, and the cross-sectional shape thereof is triangular. The side surfaces on which the two sides sandwiching the apex angle are provided are curved surface shapes that are recessed inwardly.

  Similarly, a pair of casing halves are also provided on the outlet-side protrusions 32a and 32b so that their apex angles are located on the discharge port 26 side and the cross-sectional shape protrudes in a triangular shape. 10a and 10b are provided integrally with each other, and their heights are substantially the same as the heights of the outer peripheral wall portions defining the respective internal cavities 22a and 22b. .

  And these inlet side protrusion 30a, 30b and outlet side protrusion 32a, 32b are respectively the inlet side rectification means 30 and the outlet side rectification means 32, when a pair of casing half body 10a, 10b is piled up and assembled. The fluid introduced from the suction port 24 is divided, and the divided fluid is divided into a space formed between each of the pair of rotors 20 and 20 and the inner peripheral surface of the rotor chamber 22 of the casing 10. The fluids that are respectively guided and discharged from the spaces are joined together and guided to the discharge port 26 to be discharged to the outside.

  Further, the pair of rotors 20 and 20 accommodated in the rotor chamber 22 formed in the casing 10 has a known trilobal shape as shown in FIG. It is configured as an integrated body of blades 20a, 20b, and 20c, which is positioned around a phase difference 34 with a phase difference of 120 ° and whose tip surface bulges out in a circular or arc shape. Further, a timing gear 36 is integrally provided on the rotating shaft 34 protruding from the lower surface of the rotor 20, and a bearing 38 is attached to the tip of the rotating shaft 34 protruding further from the timing gear 36. On the other hand, a bearing 38 is similarly attached to the rotating shaft 34 protruding from the upper surface of the rotor 20. The pair of rotors 20 and 20 to which the timing gear 36 and the bearing 38 are attached are, as shown in FIG. 4, provided with stepped holes 40a and 40a provided in the casing halves 10a and 10b constituting the casing 10, respectively. 42a; 40b and 42b are respectively fitted so as to be engaged with each other in the rotor chamber 22 so as to be rotated in the opposite direction as shown in FIGS.

  Here, of the pair of rotors 20, 20, the rotating shaft 34 of one of the rotors 20 is projected as shown in FIGS. 5A and 5C, and the protruding portion is shown in FIG. b), through the through hole 44 provided through the bottom of one stepped hole 42b of one casing half 10b shown in FIG. The pulley 16 shown is adapted to be fixed. That is, by rotating the pulley 16, one rotor 20 is rotated in the rotor chamber 22, and the other rotor 20 meshing with the rotor 20 is also provided with timing gears 36 provided at the lower part of the pair of rotors. Since the 36 is meshed with each other, they can be rotated in conjunction with each other so that the pair of rotors 20 and 20 can move in opposite directions as shown in FIG. As a result, the intended pumping action is exhibited.

  Therefore, in the Roots type pump having such a configuration, in the rotor chamber 22 in the casing 10, the pair of rotors 20, 20 accommodated so that the rotary shafts 34, 34 are parallel to each other, have a predetermined drive. When one of the rotors 20 is rotated by the rotation of the pulley 16 located outside that is driven to rotate by the source, the other rotor 20 is also rotated in conjunction with the rotation of the other rotor 20. A pumping action similar to that of the prior art is induced, and a predetermined fluid such as gas or liquid is introduced into the rotor chamber 22 from the suction port 24 through the suction pipe 12 and discharged outside through the discharge pipe 14 from the discharge port 26. At this time, the apex angle is located on the suction port 24 side of the rotor chamber 22 in the casing 10 at the suction port 24 side portion. Since the inlet-side protrusion 30 having a triangular shape is disposed on the inlet side, the fluid introduced from the suction port 24 is divided into left and right by the inlet-side protrusion 30 and arranged in the arrangement direction of the pair of rotors 20 and 20. Guided along the left and right inner peripheral surfaces of the rotor chamber 22 without colliding with each other in a direction orthogonal to each other, and each of the pair of rotors 20 and 20 and the inner peripheral surface of the rotor chamber 22 of the casing 10 Are smoothly guided to the space formed between the two and the fluid flow resistance can be effectively reduced, and thus the pair of rotors 22 can be effectively reduced. , 22 can be advantageously exerted, and a very efficient roots type pump can be realized.

  Moreover, in the Roots type pump according to the present embodiment, the outlet-side projection 32 similar to the inlet-side projection 30 is provided at the discharge port 26 side portion of the rotor chamber 22 in the casing 10, and the apex angle is the discharge port 26. The two flows of the fluid fed along the left and right inner peripheral surfaces of the rotor chamber 22 by the pumping action of the pair of rotors 20, 20 are arranged on the outlet side projection. The presence of 32 enables effective merging so that two flows of such fluids are advantageously prevented from colliding at a portion of the rotor chamber 22 on the discharge port 26 side. Since the flow of the fluid discharged at the discharge port 26 side portion becomes smooth, the resistance is reduced, and a more efficient pump operation can be exhibited. Than is going on.

  As described above, in the present embodiment, the inlet-side protrusions 30a and 30b are disposed as inlet-side rectifying means on the suction port 24 side portion of the rotor chamber 22 in the casing 10, and further, the rotor chamber 22 The outlet side projections 32a and 32b are also provided as outlet side rectifying means on the discharge port 26 side portion so as to rectify the discharge of the fluid from the rotor chamber 22 as the fluid flows into the rotor chamber 22. Thus, the flow of the fluid in the casing 10 can be made smoother, and the pump efficiency can be further improved. However, in the present invention, at least the above-described inlet is provided. If the side rectification means (inlet side protrusions 30a and 30b) are provided, the intended object of the present invention can be achieved.

  Further, as the inlet-side rectifying means and the outlet-side rectifying means, the side surfaces forming the sides on both sides that give the apex angles of the inlet-side protrusions 30a, 30b and the outlet-side protrusions 32a, 32b are curved surfaces recessed inwardly, The flow of the fluid guided into the rotor chamber 22 is effectively divided into two parts, and the two divided fluid flows can be effectively merged. The projections 30a and 30b and the outlet-side projections 32a and 32b may be any projections that give a simple triangular cross section, and there are other functions that serve as inlet-side rectifying means and outlet-side rectifying means. It is also possible to dispose a shaped protrusion or member.

  Further, in order to interlock the rotations of the pair of rotors 20, 20, a timing gear 36 that is meshed with each other is attached to the lower surface of each rotor 20 and is provided in the internal recess 22 a of one casing half 10 a. Sealing is performed around the rotary shaft 34 to which such a timing gear 36 is attached since it is housed in the two stepped holes 40a, 40a and is not disposed outside the casing 10. The advantage which is not necessary can be enjoyed, but of course, the present invention is not limited to this, and timing gears 36 and 36 for interlocking the pair of rotors 20 and 20 are disposed outside the casing 10. A configuration can also be employed.

  Note that the Roots pump according to the present invention is not to be construed as being limited in any way by the specific description according to the exemplary embodiment, and the present invention is not limited to various changes and modifications based on the knowledge of those skilled in the art. It should be understood that the present invention can be carried out in modes to which improvements and the like are added, and that all such modes are within the scope of the present invention without departing from the gist of the present invention. It should be.

  For example, the illustrated rotor 20 has a trilobal shape, but instead of this, a known two-lobed (gourd-shaped) rotor, a four-lobed rotor, or a rotor having a shape larger than that can also be adopted. Furthermore, the present invention can be embodied in either a single-stage pump or a multi-stage pump.

  In the illustrated embodiment, the rotation shaft 34 of one rotor of the pair of rotors 20 and 20 is used as a power shaft and is driven to rotate by the pulley 16 so that the pair of rotors 20 and 20 are shared. The rotary shafts of the pair of rotors 20 and 20 are used as power shafts, and the rotors 20 and 20 are driven to rotate in opposite directions. It is also possible to do so.

  Further, in the illustrated casing 10, the rotor chamber 22 is formed inside by superimposing the shallow box-shaped casing halves 10 a and 10 b. It is also possible to adopt a structure in which the opening of the casing body having a shape is closed with a plate-like lid, and various casing structures can be adopted as long as the target rotor chamber is formed inside. Is possible.

DESCRIPTION OF SYMBOLS 10 Casing 10a, 10b Casing half body 12 Intake pipe 14 Discharge pipe 16 Pulley 20 Rotor 22 Rotor chamber 22a, 22b Internal space 24 Inlet 26 Outlet 24a, 24b, 26a, 26b Communication part 30 Inlet side rectification means 30a, 30b Inlet side protrusion 32 Outlet side rectifying means 32a, 32b Outlet side protrusion 34 Rotating shaft 36 Timing gear 38 Bearing

Claims (10)

A casing having a suction port and a discharge port and having a rotor chamber inside, and a pair of rotors housed in the rotor chamber so that their rotation axes are parallel to each other and meshed with each other and rotated in opposite directions A roots-type pump that discharges fluid introduced from the suction port into the rotor chamber as the rotor rotates from the discharge port.
The suction port is provided in the casing so as to be positioned between the rotation shafts of the pair of rotors, while the fluid introduced from the suction port is divided, and each of the pair of rotors and the rotor inner circumferential surface of the casing A roots type pump characterized in that an inlet side rectifying means for guiding the divided fluids is disposed in a space formed between the suction port side portions in the casing.   The Roots-type pump according to claim 1, wherein the suction port is connected with a smooth curved surface to a circumferential surface of the rotor in the casing.   The Roots type pump according to claim 1 or 2, wherein the inlet side rectifying means has a triangular cross-sectional shape and is arranged so that the apex angle is located on the inlet side.   The discharge port is disposed with respect to the casing so as to face the suction port, and is discharged from a space formed between each of the pair of rotors and a rotor inner circumferential surface of the casing. The roots type pump according to any one of claims 1 to 3, wherein an outlet side rectifying means for guiding a fluid to be discharged to the discharge port is disposed at the discharge port side portion in the casing.   The Roots-type pump according to claim 4, wherein the discharge port is connected with a smooth curved surface to a circumferential surface of a rotor chamber of the casing.   The Roots-type pump according to claim 4 or 5, wherein the outlet-side rectifying means has a triangular cross-sectional shape and is arranged so that an apex angle thereof is located on the discharge port side.   The roots type pump according to any one of claims 1 to 6, wherein the rotor has a trilobal shape.   The timing gears are respectively provided on the rotation shafts of the pair of rotors, and the pair of rotors are rotated in opposite directions in conjunction with each other by engagement of the timing gears. The roots type pump according to any one of 7.   The roots type pump according to claim 8, wherein the timing gears are respectively disposed in the housing. The roots type according to any one of claims 1 to 9, wherein a rotation drive unit is attached to at least one of the rotation shafts, and the rotation drive unit rotates the at least one rotation shaft. pump.

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