JP6422280B2 - Internal gear pump - Google Patents

Description

  According to the present invention, an internal gear axially attached to a rotary shaft and an external gear arranged around the internal gear are installed in a meshed manner inside a case body in which a fluid suction port and a discharge port are formed, and the internal gear The present invention relates to an internal gear pump in which a crescent for high and low pressure partition is arranged between the external gear and the external gear.

  Conventionally, as shown in FIG. 9, for example, an internal gear 3 a that is axially attached to a rotary shaft 2 a and a periphery thereof are arranged inside a case body 1 a in which a suction port 11 a and a discharge port 12 a for a fluid such as oil are formed. An internal gear pump in which a crescent-shaped crescent 5a for high-low pressure partitioning is disposed between the internal gear 3a and the external gear 4a is known.

  In the internal gear pump, movable side plates that are in sliding contact with the gears are arranged on the side surfaces of the gears to prevent fluid leakage in the axial direction of the rotary shaft. However, clearance management is generally performed. In the case of pumps (general engine oil lubrication trochoid pumps, etc.), efficiency is maintained only with high-viscosity fluids such as oil, and gear pumps are generally not suitable for low-viscosity fluids. Pumps with high efficiency have a structure in which the movable side plate is brought into close contact with each other to reduce the amount of leakage. For example, as shown in Japanese Utility Model Publication No. 62-114183, the side plate is movable. However, high-precision processing of the movable side plate, strict dimensional control, and a pressure balance mechanism are generally performed using an elastic body such as rubber, and the movable range is narrow. Further, when the basic gear pump is used for a fluid having an extremely low viscosity, the side plate is significantly worn and has no durability. There is a problem that when the side plate is significantly worn due to deterioration with time and the dimensional change occurs, the pressure balance structure cannot be established because the range corresponding to the dimension is narrow.

Japanese Utility Model Publication No. 62-114183

  The present invention was made to solve the problems of the internal gear pump having the conventional movable side plate, and a stable load is applied even when used with a low viscosity fluid. It is an object of the present invention to reduce the efficiency, reduce the demand for the processing and dimensional accuracy of the movable side plate, improve the manufacturing performance and durability, and reduce the manufacturing price.

  The present invention, which has been made to solve the above-described problems, is configured such that an internal gear axially mounted on a rotating shaft and an external gear disposed around it are meshed inside a case body in which a fluid suction port and a discharge port are formed. A crescent for high-low pressure partitioning is disposed between the internal gear and the external gear, and a fixed side plate is disposed along one side surface of the internal gear and the external gear, and In the internal gear pump in which the movable side plate is installed along one side surface, the movable side plate is pressed against the both gears by a predetermined pressing force and a predetermined load.

  Further, the movable side plate is pressed in the direction of the internal gear and the external gear by the pressure balance rod and the spring through the support plate, and each gear that receives the load is pressed against the fixed side plate and both surfaces of the gear are sealed.

  In the present invention, the predetermined pressing force to the movable side plate is held at the predetermined pressure by the pressure balance rod installed on the support plate disposed between the case body and the movable side plate, and the case body By applying a predetermined load (spring load) with a spring that is contracted between the support plate and the load received by the pressure balance rod and the movable side plate to be equal, it is stable as a structure in which only the spring load is always applied. Performance is obtained.

  Furthermore, in the present invention, by maintaining the balance in the high-pressure seal portion of the movable side plate by the pressure balance rod, the load received by the pressure balance rod and the movable side plate is made equal, so that a structure in which only the spring load is always applied is stable. Performance is obtained.

  Furthermore, when a plurality of the pressure balance rods are provided, it is possible to prevent deterioration of the sealing performance due to the inclination of the movable side plate as compared with a single case. The main pressure balance rod arranged corresponding to the two and the two sub pressure balance rods smaller in diameter than the main pressure balance rod respectively arranged along the outer periphery of the movable side plate before and after the main pressure balance rod. Stable discharge performance can be obtained by pressing against the gear side in a balanced manner, and even without tilting the movable side plate by distributing pressure from the main pressure balance rod to the sub pressure balance rod through the pressure conduction port This prevents the movable side plate from wearing unevenly and keeps the sealing performance even when worn. It can be.

  When the rotating shaft is shared with the drive shaft of a motor that is installed integrally with the case body, when the case body also serves as the case body of the motor, the economic efficiency is improved by reducing the number of parts. As a whole, it can be made compact and light.

  According to the present invention, a stable load is not applied even when used for a low-viscosity fluid, and the efficiency is not lowered. It is possible to improve performance and increase price and durability. In particular, by maintaining the balance in the high-pressure seal portion of the movable side plate, by making the load received by the movable side plate equal, stable performance can be obtained as a structure in which only the spring load is always applied.

Sectional drawing of the principal part in the internal gear pump which is preferable embodiment which concerns on this invention. Explanatory drawing which shows the function part of the gear pump which concerns on embodiment shown in FIG. FIGS. 2A and 2B show a movable side plate according to the embodiment shown in FIG. 1, wherein FIG. 1A is a plan view of a movable side plate on a side of a gear sliding contact, and FIG. The side view of the pressure balance rod which concerns on embodiment shown in FIG. Sectional drawing of the principal part in the internal gear pump which is different embodiment of this invention. The top view by the side of the pressure balance rod of the support plate which concerns on embodiment shown in FIG. The top view at the side of the pressure balance rod of the movable side plate which concerns on embodiment shown in FIG. The side view of each pressure balance rod which concerns on embodiment shown in FIG. The principal part schematic explanatory drawing which shows a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIGS. 1 to 4 show a preferred embodiment of the internal gear pump according to the present invention, and the main parts are a fluid suction port 11 and a discharge port 12 (see FIG. 2) as in the conventional example. Inside the formed case body 1, an internal gear 3 pivotally attached to the rotary shaft 2 and an external gear 4 inscribed in the outer bearing 6 disposed around the internal gear 3 are partially engaged and installed. The crescent-shaped crescent 5 for high / low pressure partitioning is arranged between the internal gear 3 and the external gear 4 and is almost the same as that conventionally known.

  In the present embodiment, for example, a DC brushless type motor 7 is formed integrally, the base end side of the case body 1 is integrally fixed on a cover body 71 of the motor 7, and the rotating shaft is formed. No. 2 also serves as the drive shaft of the motor 7, so that the whole is compact and the number of parts can be reduced.

  In the present embodiment, the space 72 formed between the top wall 13 of the case body 1 and the cover body 71 (bottom wall 71) of the motor 7 on the base end side of the case body 1 An internal gear 3, an external gear 4, a crescent 5, an outer bearing 6, and a fixed side plate 8 are arranged, and between the front end side surface of the internal gear 3, the external gear 4 and the crescent 5 and the top wall 13 of the case body 1. The movable side plate 9 and the support plate 10 are arranged so as to be movable in the axial direction of the rotary shaft.

  Further, the support plate 10 is provided with a compression coil spring 15 which is disposed inside a slot 14 formed in the top wall 13 of the case body 1 and supported by the slot 101 of the support plate 10. The spring 15 applies a predetermined load to the movable side plate 9 via the support plate 10 to press the movable side plate 9 toward the internal gear 3 and the external gear 4.

  More specifically, as shown in FIG. 3 (a), the movable side plate 9 has a painted portion 91 on the bottom surface which is a sliding contact portion with the internal gear 3 and the external gear 4, and a portion denoted by reference numeral 92 is a low pressure portion. The high-pressure seal part. Further, the movable side plate 9 is formed with a window hole 93 for a suction stroke, a window groove 94 having a through hole 96 for a discharge process, and a fitting insertion window 95 for the crescent 5, and communicated with the through hole 96. A window groove 97 is formed to dispose the pressure balance rod 110 on the pressure balance rod side (support plate 10 side).

  The pressure balance rod 110 is disposed between the top wall 13 and the movable side plate 9 so as to partially contact the through hole 102 of the support plate 10, and the movable balance plate 110 is movable via the support plate 10. The side plate 9 is pressed against the two gears with a predetermined pressing force.

  Furthermore, in the pressure balance rod 110, the top surface 111 and the bottom surface 112 have different diameters as shown in FIG. 4, and the area B of the top surface 111 and the high pressure discharge part (formed in the case body 1 shown in FIG. The pressure area A of the discharge port 12) is designed to be equal. That is, when the pressure area A of the high-pressure discharge part formed in the case body 1 is larger than the area B of the top surface 111 of the pressure balance rod 110, the pressure of the fluid sucked by driving the pump increases. As a result, the load (surface pressure) applied to the movable side plate 9 rises and friction increases, the drive torque rises and the pump efficiency deteriorates. On the contrary, when the pressure area A of the high pressure discharge part formed in the case body 1 is smaller than the area B of the top surface 111 of the pressure balance rod 110, the fluid sucked by driving the pump from the load of the spring 15 As the pressure increases, the load (surface pressure) applied to the movable side plate 9 is weak, and in the worst case, the load cannot be obtained, resulting in discharge failure.

  Therefore, in the present embodiment, the area B of the top surface 111 of the pressure balance rod 110 and the pressure area A of the high pressure discharge portion formed in the case body 1 are designed to be equal via the support plate 10. Since the load received by the pressure balance rod 110 and the movable side plate 9 is made equal, only the load by the spring 15 is always applied to the movable side plate 9 via the support plate 10, so that the fluid sucked by driving the pump is driven. As the pressure increases, the friction increases and the efficiency is deteriorated, and the pressing load is not reduced to cause a discharge failure, so that stable discharge performance can be obtained.

  In the present embodiment, the rotating shaft 2 is rotated by driving the motor 7 and basically operates in the same manner as a conventional internal gear pump. However, in the present embodiment, the movable side plate 9 is a support plate 10. The pressure balance rod 110 is pressed against the internal gear 3 and the external gear 4 by a predetermined pressing force by the pressure balance rod 110 and a predetermined load by the spring 15 to be sealed. Since only the spring load by the spring 15 is applied by applying pressure, even if the low-viscosity fluid is used, a stable load is not applied and the efficiency is not lowered, and the movable width of the movable side plate is increased by widening the movable width of the movable side plate 9. It is possible to reduce the demand for processing and dimensional accuracy, improve manufacturing performance and durability, and reduce manufacturing price.

  FIGS. 5 to 8 show a part of different embodiments of the present invention. The overall configuration is substantially the same as that of the embodiment shown in FIGS. 1 to 4, and a predetermined position of the support plate 10 is shown. The main pressure balance rod 120 is also inserted and disposed in the through-hole 102 formed in (see FIG. 6), but in addition to the main pressure balance rod 120, the two sub pressure balance rods 130 and 140 include the The difference is that the support plate 10 and the top wall 13 of the case body 1 are inserted and arranged.

  More specifically, in the present embodiment, the main pressure balance rod 120 arranged corresponding to the high pressure discharge portion and the main pressure balance rod along the outer periphery of the movable side plate 9 (support plate 10) before and after the main pressure balance rod 120. Two sub-pressure balance rods 130 and 140 having a smaller diameter and a lower pressing force than the main pressure balance rod 120 are inserted and arranged at a predetermined symmetrical position with 120 therebetween.

  Therefore, in the present embodiment, the movable side plate 9 is pressed at a plurality of positions via the support plate 10 as compared with the case where one pressure balance rod 110 is provided as in the embodiment shown in FIGS. Therefore, it is possible to prevent the sealing performance from being lowered due to the inclination of the movable side plate 9.

  In particular, as in the present embodiment, the main pressure balance rod 120 disposed corresponding to the high pressure discharge portion and the main holes disposed in the through holes 103 and 104 formed along the outer periphery of the movable side plate 9 before and after the main pressure balance rod 120. When the sub-pressure balance rods 130 and 140 having a smaller diameter than the pressure balance rod 120 and having a lower pressing force are configured, the movable side plate 9 is balanced through the support plate 10 to the side surfaces of the internal gear 3 and the external gear 4. Stable discharge performance can be obtained by pressing to the surface.

  In addition, it is movable via the support plate 10 by distributing the pressure from the main pressure balance rod 120 to the sub pressure balance rods 130 and 140 via the pressure conduction port 17 formed in the top wall 13 of the case body 1. It is possible to press the side plate 9 in a uniform state without tilting, thereby preventing uneven wear of the movable side plate 9 and maintaining sealing performance even when worn.

  Also in the present embodiment, as shown in FIG. 3, the movable side plate 9 has a window hole 93 for suction stroke, a window groove 94 having a through hole 96 for discharge process, and an insertion for the crescent 5. A window 95 is formed, and a window groove 97 communicating with the through hole 96 is formed for disposing the main pressure balance rod 120 on the pressure balance rod side (support plate 10 side).

  Further, as shown in FIG. 7, each pressure balance rod 120, 130, 140 has the sum of the areas of the top surfaces B and the pressure area of the high pressure discharge part (discharge port 12) formed in the case body 1 shown in FIG. The high pressure discharge formed in the case body 1 and the sum of the areas B of the top surface 121 of the main pressure balance rod 120 and the top surfaces 131 and 141 of the sub pressure balance rods 130 and 140 are designed so as to be equal to A. Since the pressure applied to the movable side plate 9 through the support plate 10 is equalized by equalizing the pressure area A of the portion, only the spring load from the spring 15 is always applied to the movable side plate 9. The friction increases as the pressure of the fluid sucked by driving the motor increases and the efficiency decreases, and the pressing load decreases and discharge failure does not occur. Is the point at which the discharge performance can be obtained is similar to the embodiment shown in FIG. 1 to FIG.

  1 Case body, 2 Rotating shaft, 3 Internal gear, 4 External gear, 5 Crescent, 6 Outer bearing, 7 Motor, 8 Fixed side plate, 9 Movable side plate, 10 Support plate, 11 Suction port, 12 Discharge port, 13 Top wall, 14 groove hole, 15 spring, 16 pressure conduction port, 71 bottom wall (cover body), 72 space, 73 groove hole, 91 fill part (sliding contact part), 92 code (low pressure, high pressure seal part), 93 window hole, 94 Window groove, 95 Insertion window, 96 Through hole, 97 Window groove, 101 Groove hole, 102 Through hole, 110 Pressure balance rod, 111 Top surface, 112 Bottom surface, 120 Main pressure balance rod, 121 Top surface, 130 Sub pressure Balance rod, 131 top surface, 140 sub-pressure balance rod, 141 top surface, A pressure area of high pressure discharge section, B top surface Product

Claims (7)

Inside the case body in which at least one of the fluid suction port and the discharge port is formed on the bottom wall, an internal gear mounted on a rotary shaft disposed through the bottom wall and an outer gear disposed on the periphery thereof. The gear is installed in mesh, a crescent for high / low pressure partitioning is disposed between the internal gear and the external gear, and a fixed side plate is disposed along one side surface of the internal gear and the external gear. It established the movable side plate so as to be movable in the axial direction of the rotary shaft along the other side of the gears, internal gear the movable side plate is pressed against the two gears by a predetermined pressing force and a predetermined load In the pump,
A support plate is disposed between the top wall of the case body and the movable side plate so as to be movable in the axial direction of the rotary shaft, and a pressure balance rod is provided between the support plate and the top wall of the case body. Is arranged, and a reduced spring is arranged between the top wall and the support plate,
Pressing force given the pressing force and a predetermined load the movable side plate the pressure balance rod through the support plate to the movable side plate has on the both gears, and front Symbol movable through the support plate by the spring An internal gear pump , wherein the side plate is a load applied to both gears .   The internal gear pump according to claim 1, wherein the pressure balance rod maintains a balance in the high-pressure seal portion of the movable side plate.   The internal gear pump according to claim 1, wherein a plurality of the pressure balance rods are provided.   The main pressure balance rod disposed corresponding to the high pressure discharge portion and the two sub pressure balance rods having a smaller diameter than the main pressure balance rod respectively disposed along the outer periphery of the movable side plate. The internal gear pump according to claim 3, comprising:   The pressure from the main pressure balance rod is distributed to the sub pressure balance rod through the pressure conduction port formed in the top wall of the case body, thereby pressing the movable side plate in a uniform state without tilting. The internal gear pump according to claim 4.   6. The internal gear pump according to claim 1, wherein the rotating shaft is shared with a drive shaft of a motor installed integrally with the case body. The internal gear pump according to claim 6, wherein the case body also serves as a case body of the motor.