JP2008215100A - Internal gear pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal gear pump that reduces surface pressure of a torque transmission face of a key, and suppresses wear of a key part. <P>SOLUTION: An outer rotor 5 is rotatably fitted in a hollow hole 54 of a cylindrical barrel 4. An inner rotor 6 is provided eccentric from the outer rotor 5, and is internally in contact and engaged with the outer rotor 5. The inner rotor 6 is integrally rotatably fitted to a shaft 57 via the key 62, and a rotor stopper 64 is screwed at an end of the shaft 57. Thereby, the inner rotor 6 is fastened in the axial direction between a stepped part 57d and the rotor stopper 64. The rotation of the shaft 57 is not only transmitted to the inner rotor 6 via the key 62, but the fastening in the axial direction of the rotor stopper 64 contributes to torque transmission. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal gear pump used for an oil pump, a feed water pump, and the like.

The internal gear pump is widely used as an oil pump, and is configured by rotatably incorporating an inner rotor and an outer rotor in a casing having a suction port and a discharge port. At that time, the inner rotor is provided eccentrically with the outer rotor, and is inscribed in mesh with the outer rotor. Moreover, the number of teeth of the inner rotor is one less than the number of teeth of the outer rotor. The rotational driving force is applied to the inner rotor, and the outer rotor is also rotated in the same direction. Since it is such a structure, the liquid introduce | transduced into the clearance gap between both rotors from a suction inlet moves to a circumferential direction with the rotation of both rotors, and is sent out to a discharge outlet.
JP-A-6-167278

  Conventionally, the inner rotor (external teeth) is fitted to a shaft via a key or simply press-fitted. When the key is used, torque is transmitted from the shaft to the inner rotor only by the key. Therefore, the surface pressure increases on the torque transmission surface from the shaft to the key and the torque transmission surface from the key to the inner rotor, and the key portion is easily worn. Further, when the inner rotor is press-fitted into the shaft, the workability during assembly is poor.

  Further, conventionally, the inner rotor is not fixed in the axial direction with respect to the shaft. Even if the movement of the inner rotor in the axial direction is restricted by some means, the inner rotor is not fixed enough to help transmit torque from the shaft to the inner rotor. For this reason, if the inner rotor moves in the axial direction due to long-term use, the clearance between the inner rotor and other parts on both end faces (in the case of the invention described in Patent Document 1, between the external teeth 8 and the housing 4, The respective clearances between the teeth 8 and the cylinder block 1 are biased, and the possibility that the inner rotor is locked on the narrowed side increases.

  The problem to be solved by the present invention is to reduce the surface pressure on the torque transmission surface of the key and suppress wear of the key portion. It is another object of the present invention to reliably regulate the movement of the inner rotor in the axial direction of the shaft and suppress variations in clearance between the inner rotor and other parts on both end faces. And it makes it a subject to improve the workability | operativity at the time of an assembly, or not to deteriorate.

  The present invention has been made to solve the above problems, and the invention according to claim 1 is provided with an outer rotor that is rotatably fitted in a hollow hole of a cylindrical body, and is provided eccentrically with the outer rotor, An inner rotor that is inscribed in mesh with the outer rotor, and a shaft that is rotationally driven by a rotor stop that is screwed into the inner rotor so as to be integrally rotatable via a key, and that is axially clamped between the inner rotor and the stepped portion. And an internal gear pump.

  According to the first aspect of the present invention, the inner rotor is not only provided so as to be integrally rotatable with the shaft by the key, but is also clamped and fixed in the axial direction between the stepped portion of the shaft and the rotor stopper. . By fixing the inner rotor also in the axial direction, tightening in the axial direction of the rotor stopper helps the torque transmission, and the surface pressure on the torque transmission surface of the key can be reduced to improve the wear resistance of the key portion.

  According to a second aspect of the present invention, the cylinder is provided in a casing body having a suction port and a discharge port, and a port is provided between the casing body so as to accommodate the rotors. The shaft provided through the casing is supported by the casing body, and the rotor stopper is rotatably fitted in the port to be supported, and a gap between the rotors from one end surface or both end surfaces of the body. 2. The internal gear pump according to claim 1, wherein the liquid introduced from the suction port is sent to the discharge port as the two rotors rotate.

  According to the second aspect of the present invention, the shaft is not only supported by the casing body, but is also supported by the rotor stopper being rotatably fitted in the port. Therefore, the shaft and thus the inner rotor can be rotated more smoothly and stably. In addition, since the fitting portion between the port and the rotor stopper is a bearing portion, the configuration is simple.

  According to a third aspect of the present invention, the inner rotor is provided with a clearance fit via a key on the shaft, and the rotor stopper includes a screw hole screwed into a bolt portion provided at an end of the shaft. A cylindrical portion and an engaging portion to which a tool is hooked when screwed into the bolt portion and tightened, and the cylindrical portion is rotatably fitted in a bearing hole formed in the port. 2. The internal gear pump according to 2.

  According to the invention described in claim 3, since the inner rotor is provided on the shaft with a clearance fit, workability during assembly is good. Moreover, it is the structure which nut-tightens the rotor stop which has a cylindrical part to the bolt part of a shaft, and a structure is simple. Moreover, since the engaging part which hooks a tool when tightening a nut is provided, assembly work can be performed easily.

  According to a fourth aspect of the present invention, there is provided a two-stage structure in which the cylinder and the set of ports accommodating the two rotors are stacked in the casing body, and the two ports thus provided are provided. 4. The internal gear pump according to claim 2, wherein the rotor stop is provided at an end of the shaft at the inner and outer ports. 5.

  According to the fourth aspect of the present invention, it is possible to easily cope with an internal gear pump having a two-stage structure.

  Furthermore, the invention according to claim 5 is the internal gear pump according to any one of claims 2 to 4, wherein the shaft and the rotor stopper are made of different materials.

  According to the fifth aspect of the present invention, in the configuration in which the rotor stopper is rotated and held in the bearing hole of the port, since the rotor stopper is a separate part from the shaft, it is easy to change the material of the rotor stopper. The performance can be improved easily and inexpensively.

  According to the present invention, it is possible to reduce the surface pressure on the torque transmission surface of the key and suppress wear of the key portion. In addition, the movement of the inner rotor in the axial direction of the shaft can be reliably restricted, and variations in the clearance with other parts on both end faces of the inner rotor can be suppressed. Moreover, workability during assembly can be improved.

Next, an embodiment of the present invention will be described.
The internal gear pump of the present embodiment is typically a trochoid pump, and is used as an oil pump or a feed water pump. This internal gear pump is configured such that an inner rotor and an outer rotor are rotatably incorporated in a casing having a suction port and a discharge port.

  The casing includes a casing body and a casing lid. The casing main body is provided with a cylindrical drum, and a cylindrical outer rotor is rotatably fitted in the hollow hole of the drum, and the inner rotor is accommodated in the outer rotor.

  The outer rotor is composed of an internal gear, and the inner rotor is composed of an external gear. The inner rotor is formed to have a smaller diameter than the outer rotor, and the number of teeth is smaller than the number of teeth of the outer rotor. The inner rotor is provided in the outer rotor so as to be eccentric with the outer rotor, and is inscribed in mesh with the outer rotor.

  In this way, the cylinder in which both rotors are accommodated has a casing body on one end face and a short cylindrical port on the other end face. Thereby, both rotors are pinched | interposed between a casing main body and a port, and are accommodated in a trunk | drum. The thicknesses of both rotors are set to values obtained by subtracting the rotational clearances at both end faces from the thickness of the cylinder.

  A casing lid is formed on the casing main body so as to cover the cylinder and the port accommodating both rotors. In a state where the casing lid is attached to the casing body, a hollow portion is formed between the two, and the trunk and the port are accommodated in the hollow portion.

  The casing body is provided with a shaft therethrough and is rotatably supported. And an inner rotor is provided in this shaft so that integral rotation is possible. At this time, the inner rotor may be press-fitted with a mounting hole formed at the center thereof, but it is preferable to provide a clearance fit in consideration of workability during assembly. In any case, a key is provided between the shaft and the inner rotor. Thereby, an inner rotor is fixed to the circumferential direction with respect to a shaft. Further, the inner rotor is also fixed in the axial direction with respect to the shaft as described below.

  That is, a stepped portion is formed on the shaft, and the inner rotor is fastened and fixed in the axial direction between the stepped portion and a rotor stopper screwed into the tip of the shaft. Specifically, a bolt portion having a screw formed on the outer peripheral surface is formed on the shaft on the tip side from the fitting portion with the inner rotor. Therefore, the inner rotor can be tightened in the axial direction between the stepped portion and the rotor stopper by screwing the nut-shaped rotor stopper into the bolt portion. Or, conversely, a bolt portion is provided on the rotor stopper, and the inner rotor can be tightened in the axial direction between the stepped portion and the rotor stopper by screwing the bolt portion into a screw hole formed on the tip surface of the shaft. Good.

  A rotor stop screwed into the shaft is rotatable relative to the port. At this time, it is preferable that the rotor stopper is bearing on the port. Specifically, a circular bearing hole for bearing the rotor stopper is formed in the port, and a cylindrical portion formed on the rotor stopper is fitted into the bearing hole for bearing. The cylindrical portion is formed with a screw hole that is screwed into the bolt portion of the shaft, or conversely, is provided with a bolt portion that is screwed into the screw hole of the shaft.

  In this manner, the shaft is supported by the port via the rotor stopper, but as described above, the shaft is provided through the casing body and is also supported by the casing body. Therefore, the shaft and thus the inner rotor can be rotated smoothly and stably.

  The rotor stopper is preferably provided with an engaging portion to which a tool is hooked when the rotor stopper is screwed onto the shaft and the inner rotor is tightened. Specifically, the engaging portion is configured by a convex portion or a concave portion on which a tool such as a wrench or a screwdriver is hooked. The engaging part is preferably exposed to the outside from the port in a state where the cylindrical part is supported by the port. In this case, the rotor stopper can be screwed into the shaft even when the port is attached to the cylinder.

  By the way, the shaft is supported by the port via a rotor stopper which is a separate part. Therefore, only the rotor stopper, not the shaft, can be changed in material. Thereby, compared with the case where the material of a port or a shaft is changed, the bearing performance can be improved easily and inexpensively by changing the material.

  In the internal gear pump configured as described above, a shaft is rotationally driven by a motor provided at a base end portion thereof. When the inner rotor is rotated by the rotation of the shaft, the outer rotor is also rotated in the same direction. Since the two rotors are eccentric, the size of the gap between the two rotors varies depending on the circumferential position of the cylinder. Therefore, by arranging the suction port and the discharge port at appropriate positions on the end surface of the barrel, the liquid can be sucked from the suction port and discharged to the discharge port. That is, the liquid introduced from the suction port into the gap between the two rotors moves in the circumferential direction along with the rotation of the two rotors and is sent out to the discharge port.

  The suction port and the discharge port are formed in communication with the inside and outside of the casing body. And the liquid from the suction inlet is introduce | transduced into the clearance gap between the both rotors from the one end surface or both end surfaces of the trunk | casing in which both rotors were accommodated. The liquid introduced into the gap between the rotors at a predetermined position in the circumferential direction of the cylinder moves in the circumferential direction along with the rotation of the rotors and is sent out to the discharge port. If the liquid is introduced from both end faces of the barrel, the suction performance can be improved.

  The internal gear pump can be provided with a known pressure adjusting valve mechanism in order to adjust the discharge pressure from the pump. In the present embodiment, the pressure adjustment valve mechanism is built in the casing body and adjusts the discharge pressure of the liquid from the pump. Specifically, a part of the liquid discharged from the cylinder is returned to the suction port and / or the tank via the pressure regulating valve mechanism in the casing. By adjusting the biasing force of the pressure regulating valve mechanism biased to close the return path, the discharge pressure of the liquid from the pump is adjusted.

  In the above description, a single-stage pump has been described. However, a two-stage parallel structure may be used in some cases. In this case, the casing body and the set of ports accommodating both rotors are configured to be stacked in two stages on the casing body. Of these ports, a rotor stopper is rotatably fitted into an outer port and screwed into a bolt portion of the shaft. Similarly, it is possible to configure a pump having a higher number of stages.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIGS. 1 to 5 are views showing Embodiment 1 of the internal gear pump of the present invention, FIG. 1 is an exploded perspective view, FIG. 2 is a longitudinal sectional view in an assembled state, and FIG. 3 is III-III in FIG. 4 is a sectional view taken along line IV-IV in FIG. 2, and FIG. 5 is a sectional view taken along line VV in FIG.

  The internal gear pump of the present embodiment is a trochoid pump and is used as an oil pump. The internal gear pump according to the present embodiment includes a casing 4, an outer rotor 5, an inner rotor 6, a port 7, and a strainer 8 housed in the casing 3, in addition to the casing 3 including the casing body 1 and the casing lid 2. It is provided as a main part.

  The casing body 1 is formed in a block shape having a square cross section, and a cylindrical boss portion 9 is integrally formed at the center portion of the lower surface so as to extend downward. A flange (not shown) can be attached to the upper portion of the boss portion 9.

  As shown in FIG. 1 and FIG. 5, a suction port 10 is formed in the casing body 1 at the front left corner. Specifically, an L-shaped suction passage 11 is formed in the casing body 1 so as to open to the front surface and the left side surface thereof. And the opening part to the outer surface of the casing main body 1 of this suction path 11 is made into the suction inlets 10 and 10, respectively. The L-shaped suction path 11 is opened to the upper surface of the casing body 1 through one or a plurality of suction communication holes 12 at the corners. In the illustrated example, three suction communication holes 12, 12, 12 are formed along the vertical direction.

  A return port 13 is formed in the casing body 1 at the rear left corner. Specifically, an L-shaped return path 14 is formed in the casing body 1 so as to open to the rear surface and the left side surface. And the opening part to the outer surface of the casing main body 1 of this return path 14 is made into the return ports 13 and 13, respectively. The return path 14 communicates with the suction path 11 via the front and rear communication path 15. In the illustrated example, the suction passage 11 and the return passage 14 are communicated with each other via the front-rear communication passage 15 so that the suction port 10 on the front surface of the casing body 1 and the return port 13 on the rear surface communicate in a straight line. Yes. By the way, in this embodiment, since the return port 13 is not used, the hexagon socket plug 16 is screwed into the return port 13 and closed.

  In the casing body 1, a discharge port 17 and an air vent port 18 are formed at the front right corner. Specifically, a first horizontal hole 19 is formed in the casing main body 1 so as to penetrate in the front-rear direction. The first horizontal hole 19 intersects the first horizontal hole 19 from the right side surface of the casing main body 1 to the left and right sides of the casing main body 1. A second horizontal hole 20 is formed extending to the center in the direction. The front end of the first horizontal hole 19 is the discharge port 17, while the right end of the second horizontal hole 20 is the air vent 18. The discharge port 17 is provided with an end plug 22 via a metal packing 21, and the air vent port 18 is provided with an air vent valve 23 as desired. The air vent valve 23 is used in a closed state except that air is vented to the outside when desired.

  The second lateral hole 20 is opened to the upper surface of the casing body 1 through the discharge communication hole 24 at the left end portion. Therefore, the oil from the discharge communication hole 24 can be discharged to the outside through the end plug 22 of the discharge port 17. The end plug 22 has a stepped columnar shape with the axis line arranged in the front-rear direction, and the outer peripheral surface of the center portion is screwed into the discharge port 17 and fixed. The end portion of the end plug 22 is formed to have a smaller diameter than the first lateral hole 19, and is formed so as to cross the discharge guide holes 25 and 25 through the diameter direction. A discharge guide path 26 is formed in the end plug 22 so as to open only to the base end surface along the axis, and the discharge guide path 26 communicates with the discharge guide hole 25. Accordingly, the oil from the discharge communication hole 24 is discharged to the outside through the discharge guide hole 25 and the discharge guide path 26.

  A pressure regulating valve mechanism 27 is incorporated in the rear part of the first lateral hole 19, and the first lateral hole 19 communicates with the return path 14 via the pressure regulating valve mechanism 27 and the left and right communication passages 28. The pressure adjustment valve mechanism 27 of this embodiment includes a pressure adjustment bolt 29, a pressure adjustment nut 30, a pressure adjustment spring 31, a piston 32, a plunger 33, a poppet 34, a poppet holder 35, a plunger spring 36, and a poppet spring 37.

  The pressure adjusting bolt 29 is provided such that its head 38 is disposed at the rear portion of the first horizontal hole 19 and can only rotate within the first horizontal hole 19. The pressure adjusting bolt 29 has a hexagonal hole 39 formed in the head portion 38 and is rotated by a hexagonal wrench. A snap ring 40 is provided at the rear end portion of the first horizontal hole 19 to prevent the pressure adjusting bolt 29 from falling off. An O-ring 41 is provided between the outer peripheral surface of the head 38 of the pressure adjusting bolt 29 and the inner peripheral surface of the first horizontal hole 19 to seal the gap between them.

  The pressure adjustment nut 30 is screwed into the pressure adjustment bolt 29 so as to advance and retreat. A detent spring 42 is provided between the outer peripheral surface of the pressure adjusting nut 30 and the inner peripheral surface of the first lateral hole 19. As a result, the pressure adjustment nut 30 is not rotatable with respect to the first horizontal hole 19, but can advance and retreat along the axial direction of the first horizontal hole 19. Therefore, the pressure adjusting nut 30 can be moved in the front-rear direction by rotating the pressure adjusting bolt 29.

  The piston 32 has a cylindrical shape opened rearward, and its outer diameter corresponds to the inner diameter of the first lateral hole 19. A pressure adjusting spring 31 is disposed between the piston 32 and the pressure adjusting nut 30. The pressure adjusting spring 31 is in contact with the pressure adjusting nut 30 at the rear end portion via the spring seat 43, and is in contact with the front wall 44 of the piston 32 with the front end portion fitted into the piston 32. As a result, the piston 32 is always urged forward by the pressure adjusting spring 31 and abuts against the distal end surface 45 of the end plug 22 when the pump is not operated. A hole is formed in the center of the front wall 44 of the piston 32, and the plunger 33 is fitted into this hole.

  The plunger 33 is formed in a cylindrical shape that opens only to the rear. The hollow hole 46 communicates with the outside through a through hole 47 formed in the peripheral wall of the front end portion of the plunger 33. A poppet 34 is provided at the rear opening of the hollow hole 46 of the plunger 33. The poppet 34 has a stepped cylindrical shape, and its front end is formed in a conical portion 48. The conical portion 48 is disposed so as to contact the rear opening of the hollow hole 46 of the plunger 33.

  The poppet 34 is accommodated in a stepped cylindrical poppet holder 35. At that time, the large diameter portion of the poppet 34 is disposed in the large diameter hole, and the small diameter portion of the poppet 34 is disposed in the small diameter hole. Further, the rear end portion of the plunger 33 is fitted into the large-diameter hole of the poppet holder 35. A communication hole 49 is formed in the large diameter portion of the poppet holder 35 through the peripheral side wall.

  A plunger spring 36 is provided between the outer peripheral side step portion of the poppet holder 35 and the pressure adjustment bolt 29. Thereby, the poppet holder 35 is always urged forward. Further, a poppet spring 37 is provided between the inner peripheral side step portion of the poppet holder 35 and the step portion of the poppet 34. The poppet spring 37 is fitted into the small diameter portion of the poppet 34. Thereby, the poppet 34 is always urged forward so that the conical portion 48 closes the rear opening of the hollow hole 46 of the plunger 33.

  With the above configuration, the oil can be discharged from the discharge port 17 while returning a part of the oil from the discharge communication hole 24 to the suction port 10 via the pressure regulating valve mechanism 27. That is, by moving the piston 32 backward against the urging force of the pressure adjusting spring 31, oil is guided to the hollow hole 46 of the plunger 33 and further against the urging force of the poppet spring 37. After passing through the gap with the pipe 34, part of the oil can be returned to the suction path 11 through the communication hole 49 of the poppet holder 35, and further through the left and right communication paths 28 and the front and rear communication paths 15. Then, by rotating the pressure adjustment bolt 29 and moving the pressure adjustment nut 30 forward and backward, the urging force of the pressure adjustment spring 31 can be adjusted, and the discharge pressure of the liquid from the pump can be adjusted. In a state where the pressure adjustment spring 31 is compressed to the maximum, the pressure adjustment valve mechanism 27 can be prevented from being operated even during pressurization. That is, in this case, the return of oil from the discharge communication hole 24 to the suction port 10 is completely prevented.

  An annular groove 50 is formed on the upper surface of the casing body 1 so as to open upward. The annular groove 50 is formed by notching the upper surface of the casing body 1 downward, and the longitudinal cross-sectional shape of the groove is a square shape. The suction communication hole 12 described above is opened at the front left corner of the casing body 1 so as to cover the outer peripheral portion of the annular groove 50. On the other hand, the discharge communication hole 24 is disposed inside the annular groove 50.

  Further, a cutout 51 having a substantially T shape in plan view is formed on the upper surface of the casing body 1 so as to open upward. Specifically, after extending inward in the radial direction from the left end portion of the annular groove 50, a notch 51 is formed in a substantially T shape in plan view, extending in an arc shape on both sides in the circumferential direction. The depth of the notch 51 is the same as that of the annular groove 50.

  On the upper surface of the casing body 1, a short cylindrical body 4 is provided inside the annular groove 50. A vertical hole 52 is formed in the peripheral side wall of the body 4 so as to penetrate in the vertical direction. The lower portion of the vertical hole 52 communicates with the discharge communication hole 24 opened on the upper surface of the casing body 1. The arc-shaped portion 53 of the substantially T-shaped notch 51 formed on the upper surface of the casing body 1 is disposed in the hollow hole 54 of the body 4.

  An outer rotor 5 and an inner rotor 6 are provided in the body 4. Each of the rotors 5 and 6 is formed to have a height corresponding to the vertical dimension of the body 4. The outer rotor 5 is formed in a cylindrical shape having an outer diameter corresponding to the hollow hole 54 of the body 4. Accordingly, the outer rotor 5 can rotate along the inner peripheral surface of the hollow hole 54 of the body 4. A plurality (9 in the illustrated example) of internal teeth 55, 55,... Are provided on the inner peripheral portion of the outer rotor 5. Then, an inner rotor 6 is provided in the outer rotor 5 so as to be eccentric with the outer rotor 5 so as to be in contact with the inner teeth 55 of the outer rotor 5. On the outer peripheral portion of the inner rotor 6, external teeth 56, 56,... Having one fewer tooth than the outer rotor 5 (eight in the illustrated example) are provided.

  The inner rotor 6 is given a rotational driving force by a shaft 57. The shaft 57 is provided so as to penetrate the casing body 1 up and down. A thrust bearing 58 is provided in the boss portion 9, and the shaft 57 is rotatably supported by the casing body 1 by the thrust bearing 58. In the boss portion 9, a main shaft seal ring 59 and two oil seals 60, 60 are provided by a snap ring 61 so as not to drop off, and a gap between the shaft 57 and the casing body 1 is sealed.

  The shaft 57 has a distal end that is gradually reduced in diameter, and a large-diameter portion 57a, a medium-diameter portion 57b, and a small-diameter portion 57c are formed in order from the proximal end side. The small-diameter portion 57c is screwed into an outer peripheral surface to form a bolt portion 63. The shaft 57 having such a shape has a large-diameter portion 57 a that is passed through the casing body 1 and is bearing, and a medium-diameter portion 57 b and a small-diameter portion 57 c that protrude upward from the upper surface of the casing body 1. . At this time, the stepped portion 57d between the large-diameter portion 57a and the medium-diameter portion 57b is disposed flush with or slightly above the upper surface of the casing body 1.

  The inner rotor 6 is attached to the middle diameter portion 57 b of the shaft 57. Specifically, a circular mounting hole 6a is formed in the inner rotor 6 so as to penetrate vertically in the center thereof, and a medium diameter portion 57b is fitted into the mounting hole 6a. At this time, in consideration of workability at the time of assembly, it is preferable to fit with a clearance fit. That is, in this embodiment, the mounting hole 6a has a slightly larger diameter than the medium diameter portion 57b. The inner diameter portion 57b of the shaft 57 is fitted into the mounting hole 6a of the inner rotor 6, so that the inner rotor 6 is disposed on the upper surface of the casing body 1 and the stepped portion 57d.

  A key 62 is provided between the outer peripheral surface of the medium diameter portion 57b and the inner peripheral surface of the mounting hole 6a. In the illustrated example, a substantially rectangular key 62 whose both ends in the longitudinal direction are semicircular is used. A key groove 62 a into which approximately half of the key 62 in the thickness direction is fitted and fitted is formed on the outer peripheral surface of the intermediate diameter portion 57 b of the shaft 57 along the axial direction. On the other hand, a rectangular key groove 62a is formed on the inner peripheral surface of the mounting hole 6a of the inner rotor 6 so as to penetrate in the axial direction. A key 62 protruding from the outer peripheral surface of the medium diameter portion 57b of the shaft 57 is fitted into the key groove 62a. As a result, the inner rotor 6 can rotate integrally with the shaft 57. In a state where the lower surface of the inner rotor 6 is in contact with the stepped portion 57d, the stepped portion 57e between the medium diameter portion 57b and the bolt portion 63 is disposed slightly below the upper surface of the inner rotor 6.

  The bolt part 63 projects upward from the inner rotor 6, and a rotor stopper 64 is screwed into the bolt part 63. The rotor stopper 64 includes a cylindrical portion 64 a that is screwed into the bolt portion 63.

  The cylindrical portion 64 a is formed with a hollow hole opened downward. The hollow hole is a screw hole 63 a that is screwed into the bolt portion 63. In addition, the outer diameter of the cylindrical portion 64 a is larger than the mounting hole 6 a of the inner rotor 6. By screwing the rotor stopper 64 into the bolt portion 63 from above, the inner rotor 6 is tightened in the axial direction of the shaft 57 and is securely fixed between the stepped portion 57 d and the rotor stopper 64.

  A short cylindrical port 7 is provided on the upper surface of the cylinder 4 in which the rotors 5 and 6 are accommodated. As a result, the rotors 5 and 6 are sandwiched between the casing body 1 and the port 7 and are accommodated in the body 4. The port 7 is formed with an outer diameter corresponding to the body 4.

  A circular bearing hole 7a is formed in the port 7 so as to penetrate vertically. When the port 7 is attached to the body 4, the bearing hole 7 a is disposed on the same axis as the attachment hole 6 a of the inner rotor 6. The diameter of the bearing hole 7a corresponds to the cylindrical portion 64a. Therefore, the rotor stopper 64 screwed into the shaft 57 is supported by the cylindrical portion 64a being rotatably fitted in the bearing hole 7a. In this way, the shaft 57 is supported by the port 7 via the cylindrical portion 64a of the rotor stopper 64 screwed into the distal end portion of the shaft 57. As described above, the shaft 57 is also supported by the casing body 1. Therefore, the shaft 57 and thus the inner rotor 6 can be rotated smoothly and stably.

  On the upper surface of the cylindrical portion 64a, a convex portion having a quadrangular cross section is formed so as to protrude upward. The convex portion is used as an engaging portion 64b on which a tool is hooked when the rotor stopper 64 is screwed into the bolt portion 63. it can. The engaging portion 64 b protrudes upward from the port 7 in a state where the cylindrical portion 64 a is supported by the port 7. Therefore, even when the port 7 is attached to the trunk 4, the rotor stopper 64 can be attached to and detached from the bolt part 63.

  Bolt insertion holes 68, 68,... Are formed in the body 4 and the port 7 at positions corresponding to each other so as to penetrate in the vertical direction. Therefore, the barrel 4 and the port 7 are connected to the casing body 1 by screwing the bolts 70, 70,... Into the first screw holes 69, 69,. Can be fixed.

  On the left side of the port 7, a first suction hole 65 is formed penetrating vertically at a position facing the arcuate portion 53 of the notch 51 formed on the upper surface of the casing body 1. The first suction hole 65 is preferably formed in a tapered hole that tapers as it goes downward. The size of the lower opening 66 of the first suction hole 65 corresponds to the size of the suction hole of the conventional oil pump. In addition, a discharge groove 67 is formed on the back surface of the port 7 so as to open downward from the upper surface at a predetermined position in the cylinder 4 and the vertical hole 52 of the cylinder 4.

  In a state in which the cylinder 4 is fixed to the casing body 1, the notch 51 formed on the upper surface of the casing body 1 forms a second suction hole 71 between the casing 4 and oil from below the cylinder 4 into the cylinder 4. Can be supplied. In this manner, oil is supplied between the rotors 5 and 6 from the upper surface of the cylinder 4 through the first suction hole 65, while from the lower surface of the cylinder 4 through the second suction hole 71. Done.

  The annular groove 50 is fitted with a lower end portion of a strainer 8 made of a fine mesh cylindrical material. The casing body 1 is covered with a casing lid 2 so as to cover the body 4 and the port 7. The casing lid 2 has a cylindrical shape that opens only downward, and a square flange 72 is formed at the lower end thereof. The flange 72 is overlaid on the upper surface of the casing body 1, and cover bolts (not shown) are connected to the second screw holes 74, 74,... Of the casing body 1 through bolt passage holes 73, 73,. Screwed into. Under the present circumstances, packing (illustration omitted) is interposed between the upper surface of the casing main body 1, and the collar part 72 lower surface of the casing cover 2, and both clearance gaps are sealed. By the way, between the upper end part of the strainer 8 and the upper wall lower surface of the casing lid 2, the strainer presser 75 which consists of annular packing is arrange | positioned.

  The internal gear pump of this embodiment is operated by a motor (not shown) connected to the lower end of the shaft 57. When the shaft 57 is rotated, the inner rotor 6 is rotated, and accordingly, the outer rotor 5 is also rotated in the same direction. At this time, the shaft 57 and the inner rotor 6 rotate counterclockwise as indicated by arrows in FIG. Therefore, the rotor stopper 64 supported by the port 7 is prevented from loosening from the shaft 57. Oil from the suction port 10 is supplied to the hollow portion in the casing lid 2 through the suction communication hole 12, and after passing through the strainer 8, both rotors 5, 6 pass through the first suction hole 65 and the second suction hole 71. It is supplied to the gap between them. The oil introduced into the gap between the rotors 5 and 6 from the upper and lower end surfaces of the body 4 in this way is moved in the circumferential direction as the rotors 5 and 6 rotate, and the discharge grooves 67 formed on the lower surface of the port 7 The liquid is discharged from the end plug 22 of the discharge port 17 through the vertical hole 52 formed in the peripheral side wall of the barrel 4 and the discharge communication hole 24 of the casing body 1. At that time, by adjusting the pressure adjusting valve mechanism 27, the oil discharge pressure from the pump can be adjusted.

  Since the internal gear pump of the first embodiment has a one-stage structure, it has a simple structure, is low in cost, and can suppress variations in performance. Further, according to the internal gear pump of the first embodiment, the inner rotor 6 is fixed not only in the circumferential direction but also in the axial direction with respect to the shaft 57. That is, by screwing the cylindrical portion 64a of the rotor stop 64 into the bolt portion 63 of the shaft 57, the inner rotor 6 is fastened and fixed in the axial direction of the shaft 57 between the stepped portion 57d and the rotor stop 64. . Thus, the rotation of the shaft 57 is not only transmitted to the inner rotor 6 via the key 62, but the axial tightening of the rotor stopper 64 also helps to transmit torque. Therefore, the surface pressure on the torque transmission surface of the key 62 can be reduced, and the wear resistance of the key portion can be improved. Further, the tightening reliably restricts the movement of the inner rotor 6 in the axial direction of the shaft 57 and suppresses variations in the clearance between the two end surfaces of the inner rotor 6 and other components (casing body 1, port 7). it can.

  Further, by providing the inner rotor 6 on the shaft 57 with a clearance fit, workability during assembly is improved. Furthermore, by providing the engaging portion 64b protruding from the upper surface of the cylindrical portion 64a, the rotor stopper 64 can be screwed into the bolt portion 63 of the shaft 57 by hooking a tool on the engaging portion 64b. Therefore, the assembling work can be easily performed.

  The shaft 57 is supported by the port 7 via a rotor stopper 64 which is a separate part. Therefore, the bearing performance can be improved by changing the material of only the rotor stopper 64 instead of the shaft 57.

  FIGS. 6 and 7 are diagrams showing a second embodiment of the internal gear pump of the present invention, FIG. 6 is an exploded perspective view, and FIG. 7 is a longitudinal sectional view in an assembled state. The internal gear pump of the second embodiment is basically the same as that of the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the first embodiment, the single-stage pump has been described. In the second embodiment, a two-stage parallel structure is used. In this case, a set of a cylinder 4 and a port 7 that accommodates both rotors 5 and 6 is stacked on the upper surface of the casing body 1. Each port 7 is formed with a first suction hole 65 at a corresponding position. Further, similarly to the notch 51 formed on the upper surface of the casing body 1, a notch 76 is also formed on the upper surface of the central port 7. The notch 76 extends from the first suction hole 65 to the outer peripheral surface of the port 7 and is formed in a substantially rectangular shape on the upper surface of the port 7. In addition, the rotor stopper 64 is provided in the port 7 disposed above the port 7 as in the first embodiment. Other configurations are the same as those of the first embodiment.

  FIG. 8 is a longitudinal sectional view of an assembled state of the third embodiment of the internal gear pump of the present invention. The internal gear pump of the third embodiment is basically the same as that of the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the first embodiment, the bolt portion 63 is formed in the shaft 57, and the screw hole 63a is formed in the rotor stop 64. However, in the third embodiment, the bolt portion 63 is formed in the rotor stop 64, while A screw hole 63a is formed.

  Specifically, instead of forming the bolt portion 63 at the tip portion of the shaft 57, the bolt portion 63 is eliminated and the bolt portion 63 extending downward from its lower end surface is formed on the rotor stopper 64, while the medium diameter portion 57b. Then, a screw hole 63a is formed by opening the front end surface. In the illustrated example, the bolt part 63 is formed to project from the lower end surface of the cylindrical part 64a. Therefore, by screwing the bolt part 63 of the cylindrical part 64a into the screw hole 63a of the medium diameter part 57b, the inner rotor 6 is axially disposed between the stepped part 57d and the rotor stopper 64 via the key 62 in the axial direction of the shaft 57. It is fastened and fixed. Other configurations are the same as those of the first embodiment.

  The internal gear pump of the present invention is not limited to the configuration of each of the embodiments described above, and can be changed as appropriate. For example, the shape of the engaging portion may be a shape that allows the tool to be easily hooked, and may be a hexagonal shape. In each of the above embodiments, the engaging portion 64b is a convex portion, but a concave portion formed on the upper surface of the cylindrical portion 64a may be used. However, it is preferable that the concave engaging portion 64 b is exposed to the outside from the bearing hole 7 a of the port 7.

  Further, in each of the above embodiments, the oil supply between the rotors 5 and 6 is performed from both end surfaces of the cylinder 4, but may be configured from only one end surface thereof. With such a change, the shape of the casing body 1 or the port 7 is also changed as appropriate. For example, the cutout 51 on the upper surface of the casing body 1 may be omitted and only the first suction hole may be used.

  In the first embodiment, the return port 13 is closed and the oil from the pressure regulating valve mechanism 27 is returned to the suction port 10. However, the oil may be discharged to the outside through the return port 13. For example, it may be returned to the oil tank (not shown) via the return port 13. Moreover, although the two suction inlets 10 are provided, it can also be used, blocking either one if desired. Further, the casing body 1 may be formed by providing only one suction port 10. The same applies to the return port 13.

  Furthermore, the use of the pump is not limited to the oil pump, but can be used for a water supply pump or the like. Needless to say, the number of teeth and the tooth profile of the outer rotor 5 and the inner rotor 6 are not limited to the configuration of the above-described embodiment but can be changed as appropriate. Moreover, in each said Example, although the 1st suction hole 65 was made into the taper hole, it may not be a taper hole depending on the case. Further, in each of the embodiments described above, the second suction hole 71 is configured by forming the notch 51 (76) in the casing body 1 (further, the port 7 in the second embodiment). A notch may be formed, or the second suction hole 71 may be formed in the casing body 1 through the suction port 10.

It is a disassembled perspective view which shows Example 1 of the internal gear pump of this invention. It is a longitudinal cross-sectional view of the assembly state of the internal gear pump of FIG. It is the III-III sectional view in FIG. It is IV-IV sectional drawing in FIG. It is VV sectional drawing in FIG. It is a disassembled perspective view which shows Example 2 of the internal gear pump of this invention. It is a longitudinal cross-sectional view of the assembly state of the internal gear pump of FIG. It is a longitudinal cross-sectional view of the assembly state of Example 3 of the internal gear pump of this invention.

Explanation of symbols

1 Casing body 4 Body 5 Outer rotor 6 Inner rotor 7 Port 7a Bearing hole 10 Suction port 17 Discharge port 54 Hollow hole 57 Shaft 57d Stepped portion 62 Key 63 Bolt portion 63a Screw hole 64 Rotor stopper 64a Cylindrical portion 64b Engagement portion

Claims (5)

An outer rotor that is rotatably fitted in a hollow hole of a cylindrical body;
An inner rotor that is eccentrically provided with the outer rotor and is inscribed in mesh with the outer rotor;
An internal gear comprising: an inner rotor fitted in a rotatable manner through a key; a rotor stopper for screwing the inner rotor in an axial direction between the inner rotor and a stepped portion; pump. The barrel is provided in a casing body having a suction port and a discharge port, and a port is provided to accommodate the rotors between the casing body and the casing body.
The shaft provided through the casing body is supported by the casing body, and the rotor stopper is rotatably fitted in the port.
The liquid from the suction port introduced into the gap between the two rotors from one end surface or both end surfaces of the cylinder is sent out to the discharge port as the rotors rotate. Internal gear pump. The inner rotor is provided in the shaft with a gap fit through a key,
The rotor stopper includes a cylindrical portion having a screw hole screwed into a bolt portion provided at an end portion of the shaft, and an engagement portion to which a tool is hooked when screwed into the bolt portion and tightened.
The internal gear pump according to claim 2, wherein the cylindrical portion is rotatably fitted in a bearing hole formed in the port. In the casing body, the set of the cylinder and the port accommodating both the rotors is a two-stage structure in which two stages are stacked,
4. The internal gear pump according to claim 2, wherein the rotor stopper is provided at an end portion of the shaft in an outer port of the two ports provided in this way. 5. The internal gear pump according to any one of claims 2 to 4, wherein the shaft and the rotor stopper are made of different materials.

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