JP5047580B2 - Gear pump - Google Patents

Description

  The present invention relates to a gear pump used for conveying a fluid made of, for example, a thermoplastic resin.

  A technique related to this type of gear pump is known, in which a first gear and a second gear meshing with the first gear are used to transport an object to be transported made of, for example, a fluid. Such a technique is known that includes a closed portion that occurs at the meshing portion of the first and second gears and a communication path that communicates the outside of the closed portion (for example, Patent Document 1, Patent Document 2).

JP-A-8-105390 JP 2002-235678 A

  However, the conventional technology has a problem that the transport efficiency of the transported object is poor due to the transported object leaking through the confining portion and the communication path.

  An object of this invention is to provide the gear pump which can convey a to-be-conveyed object more efficiently.

The present invention according to claim 1 includes a first gear, a second gear meshing with the first gear, and a support means for rotatably supporting the first gear and the second gear. The first gear and the second gear are engaged with each other, a closed portion is generated, and a communication path that connects the closed portion and the outside of the closed portion is provided in the support means. The confining portion is formed so as to communicate with the suction side where the conveyed object is sucked and the discharge side where the conveyed object is discharged, and the conveyed object flows backward from the discharge side to the suction side. The gear pump further includes a blocking unit that blocks at least a part of the communication path so as to suppress the pressure, is positioned on the discharge side, and is formed integrally with the support unit .

The invention according to claim 2, wherein the supporting means includes a first bearing supporting the first gear, a gear pump according to claim 1, further comprising a second bearing supporting the second gear is there.

The present invention according to claim 3, wherein the communication passage is a gear pump according to claim 2, characterized in that formed in at least one of said first bearing and said second bearing.

The present invention according to claim 4 is the gear pump according to any one of claims 1 to 3 , wherein the first gear and the second gear are inclined gears.

According to a fifth aspect of the present invention, the communication path communicates the closed portion and the outside of the closed portion from the time when the closed portion is generated to the time when the closed portion disappears. It is a gear pump in any one of 1-4 .

  According to the present invention, it is possible to provide a gear pump capable of more efficiently transporting an object to be transported.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a transport apparatus 1 to which the present invention is applied. The conveying apparatus 1 is an apparatus that conveys an object to be conveyed inserted from the upstream side to the downstream side. For example, a polymer such as a thermoplastic resin which is a non-Newtonian fluid and is in a molten state is used as the transported object. Here, the thermoplastic resin is a resin that exhibits fluidity by heat, and is, for example, an olefin resin such as polyethylene or polypropylene, polystyrene, polycarbonate, vinyl chloride resin (hard or soft), nylon resin, polyvinyl Examples thereof include acetate resin, acrylic resin, acetal resin, thermoplastic polyester resin, and the like.

  The conveying device 1 includes a heat exchanger 2, an evaporator 3, a separator 4, a heat exchanger 5, and a separator 6, and while conveying a polymer made of a thermoplastic resin inserted from the upstream side to the downstream side. The polymer solution is evaporated to remove volatile components. A gear pump 10 is provided on the upstream side of the heat exchanger 2, between the separator 4 and the heat exchanger 5, and between the heat exchanger 5 and the separator 6. The thermoplastic resin is conveyed from the upstream side to the downstream side.

  The transport device 1 evaporates a polymer solution while transporting a polymer made of a thermoplastic resin, and an additive is added to the thermoplastic resin while the transport device 1 transports, for example, a thermoplastic resin. It is good to do. Moreover, the conveying apparatus 1 is good also as what conveys a thermoplastic resin to an injection molding apparatus, for example.

  2 to 4 show a gear pump 10 according to an embodiment of the present invention. The gear pump 10 has a gear pump main body 12 used as support means. The gear pump main body 12 includes a right side plate 14, a left side plate 16, and a connecting member 18 that connects the right side plate 14 and the left side plate 16. A hollow cavity 20 is formed by the right side plate 14, the left side plate 16, and the connecting member 18. Is forming.

  The cavity 20 communicates with a suction port 24 that is used as a suction unit that sucks a transported object such as a fluid made of a thermoplastic resin, and a discharge port 26 that is used as a discharge unit that discharges the transported object. The suction port 24 side of the cavity 20 forms a low pressure region L where the pressure is lower than that of the discharge port 26 side. Further, the discharge port 26 side of the cavity 20 forms a high pressure region H where the pressure is higher than that of the suction port 24 side.

  The gear pump main body 12 includes bearings 28 and 30 used as first bearings and bearings 32 and 34 used as second bearings. The bearings 28, 30, 32, 34 are fixed to the connecting member 18. Each of the bearings 28, 30, 32, and 34 is formed of, for example, a bearing.

  As shown in FIG. 4, the bearing 28 and the bearing 32 are arranged so that the surface 29 formed downward on the bearing 28 and the surface 33 formed on the upward surface of the bearing 32 are in close contact with each other. Has been placed. Since the surface 29 and the surface 33 are in close contact with each other, the bearing 28 and the bearing 32 are well sealed, and the conveyed object is less likely to leak from the high pressure region H to the low pressure region L. Instead of arranging the bearing 28 and the bearing 32 so that the surface 29 and the surface 33 are in close contact with each other, the bearing 28 and the bearing 32 may be integrally formed.

  Similarly to the bearing 28 and the bearing 32, surfaces are formed on the bearing 30 and the bearing 34, and the bearing 30 and the bearing 34 are fixed to the connecting member 18 so that these surfaces are in close contact with each other. Similarly to the bearings 28 and 32, the bearing 30 and the bearing 34 may be integrally formed.

  In the cavity 20, a drive gear 40 used as a first gear and a driven gear 42 used as a second gear are confiscated. The drive gear 40 is fixed to a shaft 44 that is rotatably supported by the bearing 28 and the bearing 30, and is supported by the gear pump main body 12 so as to be rotatable within the cavity 20 by the bearing 28 and the bearing 30. One end of the shaft 44 protrudes from the right side plate 14, and a drive source (not shown) such as a motor is connected to the protruding portion. Accordingly, the drive gear 40 rotates in the cavity 20 in response to the drive transmission from the drive source.

  The driven gear 42 is fixed to a shaft 46 rotatably supported by the bearing 32 and the bearing 34, and is supported by the gear pump main body 12 so as to be rotatable within the cavity 20 by the bearing 32 and the bearing 34. The driven gear 42 meshes with the drive gear 40 and rotates in the cavity 20 upon receiving drive transmission from the drive gear 40. Note that the arrows in FIG. 3 indicate the directions in which the drive gear 40 and the driven gear 42 rotate.

  An oblique gear is used as the drive gear 40 and the driven gear 42, the tooth row of the drive gear 40 is formed obliquely with respect to the longitudinal direction of the shaft 44, and the tooth row of the driven gear 42 is oblique with respect to the shaft 46. Is formed. Instead of using the inclined gears for the drive gear 40 and the driven gear 42, spur gears may be used.

  In the gear pump 10 configured as described above, when the drive gear 40 rotates in response to the drive transmission from the drive source, and the driven gear 42 rotates following the drive gear 40, the teeth of the drive gear 40 in the low pressure region L. When the row and the tooth row of the driven gear 42 are separated from each other, a conveyed object such as a fluid is sucked into the tooth groove of the drive gear 40 and the tooth groove of the driven gear 42. Then, the object to be conveyed sucked into the tooth gap is conveyed toward the high pressure region H by the rotation of the drive gear 40 and the driven gear 42. Then, the conveyed object that has been conveyed to the high-pressure region H has the teeth of the drive gear 40, the tooth row, and the driven gear 42 when the tooth row of the drive gear 40 and the tooth row of the driven gear 42 mesh in the high-pressure region H. Extruded from the groove. In this way, the object to be conveyed is conveyed from the suction port 24 side to the discharge port 26 side.

  FIG. 5 shows the side surfaces of the bearing 28 and the bearing 32 on the cavity 20 side. On the surface 29 of the bearing 28, notches 36 and 36 are formed on the suction port 24 side and the discharge port 26 side, respectively. A notch 36 is formed on the surface 33 of the bearing 32 on the suction port 24 side, and a portion facing the bearing 28 on the discharge port 26 side is a blocking portion 38 used as blocking means. A relief groove 50 used as a communication path is formed by notches 36 and 36 formed on the suction port 24 side of the bearings 28 and 32, respectively, and is connected by a notch 36 formed on the discharge port 26 side of the bearing 28. A relief groove 52 used as a passage is formed. The escape groove 50 communicates with the suction port 24 on the low pressure region L side, and the escape groove 52 communicates with the discharge port 26 on the high pressure region H. Here, the escape groove refers to a groove that communicates the inside of the closed portion 60 and the outside of the closed portion 60, which will be described later, and the object to be transported confined in the closed portion 60 via the escape groove is closed. It is discharged out of the recessed portion 60.

  When the notch is formed in the portion of the bearing 32 where the blocking portion 38 is located, the escape groove 52 is formed across the bearing 28 and the bearing 32 in the same manner as the escape groove 50. Since the discharge port 26 side of the bearing 32 is used as the blocking portion 38, the lower side of the escape groove 52 is blocked by the blocking portion 38. The blocking portion 38 is substantially the same surface as the right side surface of the driven gear 42 (the side surface on the bearing 32 side, see FIG. 2), and is in a state separated by a gap that does not interfere with the right side surface of the driven gear 42.

  FIG. 6 shows the side surfaces of the bearing 30 and the bearing 34 on the cavity 20 side. A notch 36 is formed on the surface 31 of the bearing 30 on the suction port 24 side. A portion near the surface 31 on the discharge port 26 side of the bearing 30 is a blocking portion 38 used as blocking means. The blocking portion 38 is substantially the same surface as the left side surface of the drive gear 40 (the side surface on the bearing 30 side, see FIG. 2), and is in a state separated by a gap that does not interfere with the left side surface of the drive gear 40. A notch 36 is formed on the surface 35 of the bearing 34 on the suction port 24 side. A portion near the surface 35 on the discharge port 26 side of the bearing 34 is a blocking portion 38 used as blocking means. The blocking portion 38 is substantially in the same plane as the left side surface of the driven gear 42 (the side surface on the bearing 34 side, see FIG. 2), and is separated by a gap that does not interfere with the left side surface of the driven gear 42.

  An escape groove 54 used as a communication path is formed by notches 36 and 36 formed on the suction port 24 side of the bearings 30 and 34, respectively. When notches are formed in the portion used as the blocking portion 38 of the bearing 30 and the position used as the blocking portion 38 of the bearing 34, a relief groove 56 indicated by an imaginary line is formed by these notches. However, in this embodiment, since the escape groove 56 is completely blocked by the blocking portion 38 of the bearing 30 and the blocking portion 38 of the bearing 34, the escape groove 56 is not formed. When the escape groove 56 is formed, it communicates with the discharge port 26 corresponding to the high pressure region H side.

  7 and 8 show the meshing portion of the drive gear 40 and the driven gear 42 in an enlarged manner. When the drive gear 40 and the driven gear 42 that are in contact with each other only by the tangent line B are rotated to the position shown in FIG. 7, they are in contact with each other at the tangent line A in addition to the tangent line B. Then, the drive gear 40 and the driven gear 42 continue to rotate while maintaining the contact state at two locations of the tangent line A and the tangent line B, and the drive gear 40 and the driven gear 42 have rotated to the position shown in FIG. At the time, the drive gear 40 and the driven gear 42 are separated from each other at the tangent B portion.

  At the position shown in FIG. 7, the confining portion 60 is generated at a position surrounded by the tangent line A and the tangent line B. Then, at the position shown in FIG. 8, the state in which the closing portion 60 is formed is maintained until the driving gear 40 and the driven gear 42 are separated at the tangent line B and the closing portion 60 disappears. The volume of the confinement part 60 changes as the drive gear 40 and the driven gear 42 rotate, and gradually decreases from the time when the confinement part 60 shown in FIG. 7 is formed to an intermediate time point. After that, it gradually increases until the closing portion 60 shown in FIG. 8 disappears. For this reason, the object to be transported confined in the confining part 60 is compressed before the intermediate point of time passes, and the pressure in the confining part 60 increases, and the drive source and the bearings 28, 30, 32, 34 are increased. There is a risk that the load of the gear pump 10 will increase, the life of the gear pump 10 will be shortened, and noise may be generated when the conveyed object is compressed. When the transported object is made of, for example, a thermoplastic resin and does not easily contract even when pressure is applied, there is a particularly high possibility of an increase in load applied to the drive source and the generation of noise.

  Therefore, in this gear pump 10, the escape groove 50 and the escape groove 52 provided on the cavity 20 side are formed by the bearing 28 and the bearing 32 as described above, and as shown in FIGS. The transported object confined in the closed portion 60 can escape from the closed portion 60 by communicating with at least one of the escape groove 50 or the escape groove 52 according to the state of rotation. . By allowing the conveyed object to escape from the confining portion 60, an increase in pressure due to compression of the conveyed object is suppressed, and the life of the gear pump 10 may be shortened or noise may be generated. Is reduced. 7 and 8 show the right side of the gear pump 10, escape grooves 54 and 56 (see FIG. 6) can be formed on the left side of the gear pump 10, and the drive gear 40 and the driven gear 42 are Depending on the state of rotation, the closing portion 60 can be communicated with at least one of the escape groove 54 or the escape groove 56.

  In order to suppress an increase in pressure in the confining portion 60, the confining portion 60 extends from the time when the confining portion 60 shown in FIG. 7 occurs until the time when the confining portion 60 shown in FIG. 8 disappears. It is desirable to maintain a state where the inside and the outside of the confining portion 60 communicate with each other. That is, the closing portion 60 is in any one of the escape grooves 50, 52, 54, and 56 until the drive gear 40 and the driven gear 42 are rotated from the position shown in FIG. 7 to the position shown in FIG. It is desirable to communicate. Therefore, in this embodiment, the position of the tangent on the downstream side in the rotational direction of the gear at the time when the drive gear 40 and the driven gear 42 start contact at the two tangents (position of the tangent B shown in FIG. 7) The escape groove 50 is formed so that the end of the escape groove 50 is positioned on the closed portion 60 side. That is, the escape groove 50 is formed at a position where the end of the escape groove 50 is on the right side in the drawing with respect to the line segment L1 shown in FIG. By forming the relief groove 50 at this position, the closure portion 60 is kept in communication with the relief groove 50 from the time when the closure portion 60 is generated to the time when the closure portion 60 disappears.

  In this embodiment, the upstream side tangent at the time when the drive gear 40 and the driven gear 42 that have been in contact with each other at the two tangents are separated at the position of the tangent located downstream in the rotational direction of the gear. The escape groove 52 is formed so that the end of the escape groove 52 is located on the closed portion 60 side from the position (position of the tangent A shown in FIG. 8). That is, the escape groove 52 is formed so that the end of the escape groove 52 is on the left side of the line segment L2 shown in FIG. By forming the escape groove 52 at this position, the closed portion 60 is kept in communication with the escape groove 52 from the time when the closed portion 60 is generated until the time when the closed portion 60 disappears.

  The drive gear 40 and the driven gear 42 are inclined gears as described above. For this reason, the tangent line A and the tangent line B are not formed perpendicularly to the paper surface in FIGS. 7 and 8 from the paper surface side to the back surface of the paper surface, but from the right side in the drawing from the paper surface side to the back surface of the paper surface. It is formed to tilt to the left. This inclination is determined according to the twist angle of the drive gear 40 and the driven gear 42, and the tilt increases as the twist angle increases. For this reason, the positions where the escape grooves 50, 52, 54, 56 are formed so that the closing portion 60 is in communication with any of the escape grooves 50, 52, 54, 56 are located at the drive gear 40 and It is set according to the twist angle of the driven gear 42.

  Depending on the rotation state of the drive gear 40 and the driven gear 42, the closing portion 60 communicates with one end side via the escape groove 52 or escape groove 56 to the high pressure region H, and the other end side via the escape groove 50 or escape groove 54. There may be a state of communication with the low pressure region L. In this case, the object to be conveyed flows backward due to the pressure difference from the high pressure region H on the discharge port 26 side to the low pressure region L on the suction port 24 side, leaks out, and can be transported by the gear pump 10 per unit time. In some cases, the amount of the conveyed object that can be reduced is reduced. In particular, in the gear pump 10 of this embodiment, since the inclined gears are used as the drive gear 40 and the driven gear 42, the closing portion 60 is formed at an angle with respect to the shaft 44 and the shaft 46, and is conveyed. The backflow of things tends to occur. In view of this, the gear pump 10 is uniquely designed to make it difficult for the conveyed object to flow backward from the discharge port 26 side to the suction port 24 side, so that the conveyed object can be efficiently conveyed.

  That is, in the gear pump 10 according to this embodiment, as described above, a part of the bearing 32, the bearing 30, and the bearing 34 are respectively used as the blocking portions 38, 38, and 38, and a part of the escape groove 52 is blocked. All parts of the escape groove 56 are blocked. As described above, since the blocking portions 38, 38, and 38 are in a state where at least a part of the closed portion 60 and the communication path communicating with the outside of the closed portion 60 are blocked, the object to be conveyed is discharged from the discharge port 26 side. It can be made difficult to flow backward to the suction port 24 side. In particular, since the escape groove 56 is entirely cut off, the closed portion 60 is sealed at one end side, and the backflow of the conveyed object is less likely to occur.

  In the embodiment described above, a part of the escape groove 52 and the whole part of the escape groove 56 are blocked. However, it is sufficient that at least a part of the escape grooves 50, 52, 54, 56 is blocked. Which part of the relief grooves 50, 52, 54, 56 is to be cut off can be formed as notches in the four bearings 28, 30, 32, 34, and can be used as a blocking portion 8 It can be determined from the location of the location where the notch is formed and which location is used as the blocking portion.

  In FIG. 9, from the position where the notches of the bearings 28 and 32 located on the right side of the gear pump 10 can be formed and can be used as the blocking part, which position is used as the blocking part. The combinations of positions that can be selected for are shown. First, as shown in FIG. 9A, it is possible to select to use all four places as the blocking portion 38. Further, as shown in FIG. 9B to FIG. 9E, it is possible to select to form the notch 36 at one place by using three of the four places as the blocking portion 38. Further, as shown in FIGS. 9 (f) to 9 (k), it is possible to select to use two of the four locations as the blocking portion 38 and form the notches 36 at the two locations. Further, as shown in FIGS. 9 (l) to 9 (o), it is possible to use one place as the blocking portion 38 and to form the notches 36 at three places. Further, as shown in FIG. 9 (p), it is possible to choose not to use the four portions as the blocking portions 38 but to form the notches 36. However, as shown in FIG. 9 (p), when it is selected to form the notches 36 in all four places, the four places that can be used as the blocking portions 38 in the bearings 30 and 34 located on the left side of the gear pump 10 are used. Of these positions, at least one place needs to be selected for use as the blocking portion 38. When none of the eight positions that can be used as the blocking portion 38 in the four bearings 28, 30, 32, and 34 is used as the blocking portion, the effect of preventing the backflow of the conveyed object can be obtained. Can not.

  Among those shown in FIG. 9, it is particularly desirable to form a notch 36 at the position shown in FIG. 9B or 9D. When the notch 36 is formed at the position shown in FIG. 9B, the escape groove 50 is not formed, and only the upper side of the escape groove 52 is formed. For this reason, the closing part 60 is kept in communication with the escape groove 52 from the time when the closing part 60 is generated to the time when the closing part 60 disappears (see FIGS. 7 and 8). The pressure increase in 60 is suppressed. On the other hand, since the escape groove is not formed at a position other than the upper side of the escape groove 52, the backflow of the conveyed object from the high pressure region H to the low pressure region L hardly occurs.

  When the notch 36 is formed at the position shown in FIG. 9D, the notch 52 is not formed, and only the lower side of the notch 50 is formed. For this reason, the closing part 60 is kept in communication with the escape groove 50 from the time when the closing part 60 is generated to the time when the closing part 60 disappears (see FIGS. 7 and 8). The pressure increase in 60 is suppressed. On the other hand, since the escape groove is not formed at a position other than the lower side of the escape groove 50, the backflow of the conveyed object from the high pressure region H to the low pressure region L hardly occurs.

  FIG. 9 shows combinations of positions that can be selected for use as the blocking portion 38 among the four locations that can be used as the blocking portion 38 of the bearings 28 and 32 located on the right side of the gear pump 10. However, for the bearings 30 and 34 located on the left side of the gear pump 10, as in the bearings 28 and 32, the position used as the blocking portion 38 can be selected. Similarly to the case shown in FIG. 9 (p), when neither of the bearings 30 and 34 located on the left side is used as the blocking portion 38, the bearings 30 and 34 located on the right side of the gear pump 10 Of the four locations that can be used as the blocking portion 38, at least one location needs to be used as the blocking portion 38.

  As described above, the present invention can be applied to a gear pump used for conveying a fluid made of, for example, a thermoplastic resin.

It is a schematic block diagram which shows the conveying apparatus with which the gear pump based on embodiment is used for this invention. It is sectional drawing which shows the gear pump which concerns on embodiment of this invention. It is sectional drawing which shows the AA cross section in FIG. 2 of the gear pump which concerns on embodiment of this invention. It is sectional drawing which shows the BB cross section in FIG. 2 of the gear pump which concerns on embodiment of this invention. It is explanatory drawing explaining the shape of the gear side surface of the bearing of the right side surface side used for the gear pump which concerns on embodiment of this invention. It is explanatory drawing explaining the shape of the gear side surface of the bearing of the left side surface used for the gear pump which concerns on embodiment of this invention. It is explanatory drawing which expands and shows the part which the gear of the gear pump which concerns on embodiment of this invention meshes | engages, and shows the state at the time of a closed part generating. It is explanatory drawing which shows the state at the time of the enlarged part which shows the part which the gear of the gear pump which concerns on embodiment of this invention meshes | engages, and the confinement part lose | disappeared. It is explanatory drawing explaining the arrangement | positioning which can be selected about which position of the two bearings arrange | positioned at the right side surface side is used as a interruption | blocking part in the gear pump which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conveyor apparatus 2 Heat exchanger 3 Evaporator 4 Separator 5 Heat exchanger 6 Separator 10 Gear pump 12 Gear pump main body 14 Right side plate 16 Left side plate 18 Connecting member 20 Cavity 24 Suction port 26 Discharge port 28, 30, 32, 34 Bearing 29, 31, 33, 35 Surface 36 Notch 38 Blocking part 40 Drive gear 42 Driven gear 44, 45 Shaft 50, 52, 54, 56 Relief groove 60 Containment part A, B Tangent H High pressure area L Low pressure area

Claims (5)

The first gear,
A second gear meshing with the first gear;
Support means for rotatably supporting the first gear and the second gear;
Have
A constriction occurs at the meshing portion of the first gear and the second gear;
A communication path that communicates between the closed portion and the outside of the closed portion is formed in the support means ,
The confining portion communicates with a suction side where a conveyed object is sucked and a discharge side where the conveyed object is discharged,
A blocking means that blocks at least a part of the communication path so as to prevent the conveyed object from flowing backward from the discharge side to the suction side, is located on the discharge side, and is formed integrally with the support means Further having a gear pump. Said support means, said a first bearing supporting the first gear, the gear pump of claim 1, further comprising a second bearing supporting the second gear. The communication passage, said first bearing and said second claim 2 gear pump according formed on at least one of the bearings. The gear pump according to any one of claims 1 to 3, wherein the first gear and the second gear are inclined gears. The communication passage, from the time when the closed portion occurs up to the point where the closed portion disappears, claims 1 to 4 gear pump according to any one communicating with the outside of the closed portion and the closed portion.

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