JP6115156B2 - Inscribed gear pump - Google Patents

Description

  The present invention relates to an internal gear pump.

  As a pump for supplying a working fluid when an actuator such as a hydraulic cylinder is driven, for example, an internal gear pump disclosed in Patent Document 1 is known. In the internal gear pump, an inner gear having external teeth and an outer gear having internal teeth meshed with the external teeth are accommodated in a housing, and both gears are disposed in a non-engagement region where the external teeth and the internal teeth do not mesh. A partition member is slidably in contact with the tooth tip. In the internal gear pump, the outer gear rotates in synchronization with the rotation of the inner gear, the working fluid is sucked in between the tooth surfaces from the suction port of the housing, and the working fluid is discharged from the discharge port of the housing.

JP 2004-308547 A

The efficiency of the internal gear pump decreases when the working fluid leaks from the high pressure side to the low pressure side. For this reason, it is necessary to improve the sealing performance between the partition member and the tooth tip.
The present invention was made paying attention to such problems existing in the prior art, and an object of the present invention is to provide an internal gear pump that achieves high efficiency by improving the sealing performance. is there.

An internal gear pump that solves the above problems includes a housing that houses an inner gear having external teeth and an outer gear having internal teeth that mesh with the external teeth, and a non-engagement region in which the external teeth and the internal teeth do not mesh with each other. A partition member disposed in the housing, a suction port formed in the housing and sucking a working fluid between tooth surfaces of the inner gear and the outer gear, and formed in the housing and operated from between the tooth surfaces An internal gear pump having a discharge port for discharging fluid, wherein the partition member includes an inner peripheral surface including a sliding contact surface that is in sliding contact with a tooth tip of the inner gear, and a sliding member that is in sliding contact with a tooth tip of the outer gear. An outer peripheral surface including a contact surface, and a space between the tooth surfaces of the inner gear and the outer gear is defined by an outer peripheral surface of the partition member and a tooth surface of the outer gear. Comprising a low pressure chamber connected to a drain port formed in said housing while being, the partition member includes a first member having a tooth tip sliding contact sliding surface of the inner gear, the tooth tip of the outer gear And a second member and a third member that are slidably contacted with each other and spaced from the first member along the flow direction of the working fluid. The first member and the third member Sealing of leakage of working fluid from the high pressure side to the low pressure side through the tooth tips of the inner gear and the outer gear between the second member and between the first member and the third member, respectively. A sealing member is interposed, and the low-pressure chamber is located between the sealing members . According to this configuration, the partition member can be pressed against the inner gear and the outer gear by the action of the low pressure chamber. Thereby, the sealing performance of the tooth tip of the inner gear and the tooth tip of the outer gear can be improved. Therefore, high efficiency can be achieved.

  In the internal gear pump, the outer gear has a cylindrical shape, and has a plurality of inlet / outlet holes that penetrate the inner and outer peripheral surfaces and allow the working fluid to flow into and out of the suction port and the discharge port. It is preferable that a concave portion to which the drain port is connected is formed on a sliding contact surface with which an outer peripheral surface of the outer gear is in sliding contact. According to this configuration, the low pressure chamber and the drain port can be favorably connected through the recess. Therefore, the low pressure chamber can be formed satisfactorily. Further, it is possible to obtain a lubricating action on the outer periphery of the outer gear.

  In the internal gear pump, an introduction groove into which a high-pressure working fluid is introduced is formed in a sliding contact surface in which the outer peripheral surface of the outer gear is in sliding contact with the housing. It is preferable to include a first introduction groove connected to the discharge port and a second introduction groove connected to the discharge port. According to this configuration, the radial load applied to the outer gear during rotation can be received by the high-pressure working fluid introduced into the introduction groove. Further, it is possible to obtain a lubricating action on the outer periphery of the outer gear.

  In the internal gear pump, it is preferable that the first introduction groove and the second introduction groove have an asymmetric shape. According to this configuration, when rotating in one direction, the radial load applied to the outer gear during rotation can be appropriately received regardless of whether the suction port is at a low pressure or a high pressure.

  According to the present invention, high efficiency can be achieved by improving the sealing performance.

Sectional drawing of an internal gear pump. The partial expanded sectional view of an internal gear pump. The perspective view of an outer gear. The perspective view which shows the inner side of a housing. The perspective view which shows the inner side of a housing.

Hereinafter, an embodiment in which an internal gear pump is embodied will be described with reference to FIGS.
As shown in FIG. 1, the internal gear pump 10 includes an inner gear 12 and an outer gear 13 that are combined in a housing 11. The inner gear 12 is an external gear serving as a pinion gear, and is fixed to the rotating shaft 14. The outer gear 13 is a cylindrical internal gear arranged eccentrically on the outer side of the inner gear 12, and is rotatably accommodated in an accommodation hole 15 formed in the housing 11. The inner gear 12 and the outer gear 13 mesh with each other in a circumferential direction. An arcuate partition member 17 is disposed in the non-engagement region 16 where the outer teeth of the inner gear 12 and the inner teeth of the outer gear 13 do not mesh.

  As shown in FIG. 2, the partition member 17 includes an inner peripheral surface including a sliding contact surface 18 that is in sliding contact with the tooth tip of the inner gear 12, and an outer side including sliding contact surfaces 19 and 20 that are in sliding contact with the tooth tip of the outer gear 13. And a peripheral surface. In this embodiment, the partition member 17 includes an arc-shaped first member 21 having a sliding contact surface 18, an arc-shaped second member 22 having a sliding contact surface 19, and an arc-shaped third member 23 having a sliding contact surface 20. , Is composed of.

  On the peripheral surface of the first member 21 opposite to the slidable contact surface 18, a convex portion 24 that is located at the center in the circumferential direction and projects toward the tooth tip of the outer gear 13, and on both sides of the convex portion 24. And recessed portions 25 and 26 that are located and recessed toward the sliding contact surface 18. A second member 22 is disposed in the recess 25 of the first member 21, and a groove 27 formed in the recess 25 is formed by a seal pin 28 that seals a gap between the first member 21 and the second member 22, and the seal pin 28. A leaf spring 29 for assisting the sealing function is provided. In addition, a third member 23 is disposed in the recess 26 of the first member 21, and a seal pin 31 that seals a gap between the first member 21 and the third member 23 in a groove 30 formed in the recess 26, and a seal pin A leaf spring 32 for assisting the sealing function by 31 is provided.

  As shown in FIG. 3, the outer gear 13 has a plurality of communication holes 13 a penetrating the inner and outer peripheral surfaces. Each communication hole 13 a passes through the outer peripheral surface of the outer gear 13 and the tooth bottom of the outer gear 13.

  Further, as shown in FIG. 1, the housing 11 is formed with a first port 33 as a suction port and a second port 34 as a discharge port communicating with the accommodation hole 15 from the radial direction of the outer gear 13. The first port 33 and the second port 34 are respectively formed on end surfaces of the housing 11 that face each other in a direction orthogonal to the axial direction. Each communication hole 13a of the outer gear 13 functions as an inflow / outlet hole for the working fluid flowing through the first port 33 and the second port 34. In the internal gear pump 10 of this embodiment, the working fluid is in the radial direction of the outer gear 13. Flows into and out of the outer gear 13. Further, it is a part of the peripheral surface of the housing hole 15 of the housing 11 and bulges in the radial direction of the outer gear 13 at a position corresponding to the convex portion 24 of the first member 21 constituting the partition member 17. A recessed portion 35 that is recessed is formed. A drain port 36 communicating with the recess 35 is formed in the housing 11.

  As shown in FIGS. 4 and 5, the working fluid is introduced into the sliding contact surface 15 a where the outer peripheral surface of the outer gear 13 is slidably contacted in the accommodation hole 15 and is connected to the opening 33 a of the first port 33. The first introduction groove 37 and the second introduction groove 38 that is connected to the opening 34 a of the second port 34 and into which the working fluid is introduced are formed. The first introduction groove 37 and the second introduction groove 38 are extended in the circumferential direction of the accommodation hole 15. In this embodiment, the first introduction groove 37 and the second introduction groove 38 have different shapes and asymmetric shapes.

Hereinafter, the operation of the inscribed gear pump 10 will be described.
The inscribed gear pump 10 of this embodiment is a pump that can rotate in one direction.
When a low-pressure working fluid is circulated through the first port 33, the working fluid is a region in which the interval between the tooth tips of the inner gear 12 and the outer gear 13 spreads in the rotation direction through the communication hole 13 a of the outer gear 13. Sucked into. The sucked working fluid is conveyed to the downstream side in the rotation direction via the inner peripheral surface and the outer peripheral surface of the partition member 17. Then, as the working fluid approaches the second port 34, the working fluid is compressed and becomes high pressure because the interval between the tooth tips becomes narrower in the rotation direction, and is discharged from the second port 34.

  In the internal gear pump 10 of this embodiment, since the drain port 36 is connected, the pressure around the convex portion 24 of the first member 21 in the partition member 17 is always low. That is, a low-pressure chamber 39 that is partitioned by the outer peripheral surface of the partition member 17 and the tooth surface of the outer gear 13 and connected to the drain port 36 is formed in the peripheral portion of the convex portion 24. As shown in FIG. 2, the low-pressure chamber 39 is in a region between the seal pin 28 between the first member 21 and the second member 22 and the seal pin 31 between the first member 21 and the third member 23. It is formed.

  For this reason, when the second port 34 is at a high pressure, the sliding contact surface 20 of the third member 23 of the outer gear 13 is caused by a pressure difference between the low pressure chamber 39 and the downstream side of the low pressure chamber 39 in the rotational direction. While being pressed against the tooth tip, the sliding contact surface 18 of the first member 21 is pressed against the tooth tip of the inner gear 12. Thereby, leakage of the working fluid from the high pressure side to the low pressure side through the tooth tips of the inner gear 12 and the outer gear 13 is sealed.

  In addition, the working fluid from the low pressure chamber 39 flows out by connecting the communication hole 13 a of the outer gear 13 and the drain port 36. In the internal gear pump 10 of this embodiment, since the recess 35 is formed at a position corresponding to the drain port 36 and the flow path leading to the drain port 36 is widened, the working fluid can easily flow out from the low pressure chamber 39. The working fluid reaching the recess 35 is not only discharged to the drain port 36, but also flows out to the sliding contact surface 15a which is the peripheral surface of the accommodation hole 15 and the outer peripheral surface of the outer gear 13 is in sliding contact. Cause an effect. Further, when the second port 34 is at a high pressure, a radial load is applied to the outer gear 13 in the direction of arrow A shown in FIG. 1, and this load is actuated by the high pressure introduced into the second introduction groove 38. Supported by fluid. The working fluid introduced into the second introduction groove 38 also flows out to the peripheral surface (sliding contact surface 15 a) of the accommodation hole 15, thereby causing a lubricating action.

  On the other hand, when a high-pressure working fluid is circulated through the first port 33, the working fluid is transported between the tooth surfaces of the inner gear 12 and the outer gear 13 and discharged from the second port 34 as described above. When the first port 33 is at a high pressure, the second port 34 is at a low pressure. As described above, when the first port 33 is set to a high pressure, the sliding contact surface 19 of the second member 22 has teeth of the outer gear 13 due to a pressure difference between the low pressure chamber 39 and the upstream side of the low pressure chamber 39 in the rotational direction. While being pressed first, the sliding contact surface 18 of the first member 21 is pressed against the tooth tip of the inner gear 12. Thereby, leakage of the working fluid from the high pressure side to the low pressure side through the tooth tips of the inner gear 12 and the outer gear 13 is sealed. In other words, in the internal gear pump 10 of this embodiment, the working fluid leaks from the high pressure side to the low pressure side due to the action of the low pressure chamber 39 regardless of which of the first port 33 and the second port 34 becomes high pressure. Is sealed.

  Further, when the first port 33 is at a high pressure, a radial load is applied to the outer gear 13 in the direction of arrow B shown in FIG. 1, and this load is actuated by the high pressure introduced into the first introduction groove 37. Supported by fluid. When the internal gear pump 10 is rotated in one direction, the radial load applied to the outer gear 13 when the first port 33 is set to a low pressure and the first port 33 is set to a high pressure is indicated by arrows A and B in FIG. As shown in FIG. In response to this load, the outer gear 13 moves in a direction shifted in the rotational direction with respect to the direction of the load. Since the first introduction groove 37 and the second introduction groove 38 are preferably arranged in consideration of the respective moving directions of the outer gear 13, they do not have the same shape but become asymmetric shapes.

  The internal gear pump 10 of this embodiment is suitable, for example, when the internal gear pump 10 is used in both a hydraulic pump and a hydraulic motor in a hydraulic circuit that drives a hydraulic cylinder. When the internal gear pump 10 is a hydraulic motor, for example, the inner gear 12 is rotationally driven by a high-pressure working fluid discharged from a hydraulic cylinder, and a regenerative operation is performed using the electric motor connected to the rotating shaft 14 of the inner gear 12 as a generator. For example. Further, the internal gear pump 10 of this embodiment can be used both when the working fluid is circulated from the first port 33 and when the working fluid is circulated from the second port 34. For this reason, when working fluid is circulated in this way, the internal gear pump 10 can be driven to rotate in both directions.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) By the action of the low pressure chamber 39, the sliding contact surface 18 of the first member 21 constituting the partition member 17 can be pressed against the tooth tip of the inner gear 12, and the sliding contact surface 19 and the second member 22 of the second member 22 The sliding contact surfaces 20 of the three members 23 can be pressed against the tooth tips of the outer gear 13 respectively. Thereby, the sealing performance of the tooth tip of the inner gear 12 and the tooth tip of the outer gear 13 can be improved. Therefore, high efficiency can be achieved.

(2) The low pressure chamber 39 and the drain port 36 can be satisfactorily connected by the recess 35. Therefore, the low pressure chamber 39 can be formed satisfactorily.
(3) Moreover, the lubricating action of the outer periphery of the outer gear 13 can be obtained by the working fluid reaching the recess 35. Therefore, baking etc. can be prevented.

  (4) The first introduction groove 37 and the second introduction groove 38 can receive a radial load applied to the outer gear 13 during rotation with a high-pressure working fluid. And the friction loss which generate | occur | produces on the outer periphery of the outer gear 13 and the surrounding surface (sliding contact surface 15a) of the accommodation hole 15 can be reduced, and high efficiency can be achieved.

  (5) Further, the lubricating action of the outer periphery of the outer gear 13 can be obtained by the working fluid reaching the first introduction groove 37 and the second introduction groove 38. Therefore, baking etc. can be prevented.

  (6) Since the first introduction groove 37 is connected to the first port 33 and the second introduction groove 38 is connected to the second port 34, any one of the first port 33 and the second port 34 has a high pressure. Even so, the working fluid can be introduced into each of the first introduction groove 37 and the second introduction groove 38.

  (7) When the internal gear pump 10 is rotated in one direction, since the first introduction groove 37 and the second introduction groove 38 are asymmetrical, any of the first port 33 and the second port 34 has a high pressure. Even if it becomes, the radial load provided to the outer gear 13 at the time of rotation can be received appropriately.

In addition, you may change this embodiment as follows.
○ The position and shape of the low pressure chamber 39 may be arbitrarily changed.
The working fluid may flow in and out from the axial direction between the tooth surfaces of the inner gear 12 and the outer gear 13. That is, the first port 33 and the second port 34 are formed in the housing 11 so as to open in the axial direction. In this case, the communication hole 13 a may not be formed in the outer gear 13. In addition, the drain port 36 connected to the low pressure chamber 39 is formed in the housing 11 so as to open in the axial direction like the first port 33 and the second port 34.

  The shape of the recess 35 may be changed according to the connection state between the low pressure chamber 39 and the drain port 36, or may not be formed as long as the low pressure chamber 39 and the drain port 36 can be connected satisfactorily.

  When the internal gear pump 10 is rotated in both directions, the first introduction groove 37 and the second introduction groove 38 may have the same shape (symmetrical shape). When rotating in both directions, the first port 33 becomes a suction port and a discharge port, and the second port 34 becomes a suction port and a discharge port.

In the following, technical ideas that can be understood from the above embodiment and other examples will be added.
(1) The partition member has a first member having a sliding contact surface in sliding contact with the tooth tip of the inner gear, a sliding contact surface in sliding contact with the tooth tip of the outer gear, and the flow direction of the working fluid with respect to the first member. The second member and the third member are spaced apart from each other, and seal pins are interposed between the first member and the second member and between the first member and the third member, respectively. The low pressure chamber is located between the seal pins.

DESCRIPTION OF SYMBOLS 10 ... Internal gear pump, 11 ... Housing, 12 ... Inner gear, 13 ... Outer gear, 13a ... Communication hole, 16 ... Non-meshing area | region, 17 ... Partition member, 18, 19, 20 ... Sliding contact surface, 21 ... 1st Member, 22 ... second member, 23 ... third member, 28 , 31 ... seal pin (seal member), 33 ... first port, 34 ... second port, 35 ... recess, 36 ... drain port, 37 ... first Introducing groove 38 ... second introducing groove 39 ... low pressure chamber.

Claims (4)

A housing that houses an inner gear having external teeth and an outer gear having internal teeth that mesh with the external teeth, a partition member that is disposed in a non-engagement region where the external teeth and the internal teeth do not mesh, and the housing And a suction port that sucks the working fluid between the tooth surfaces of the inner gear and the outer gear, and a discharge port that is formed in the housing and discharges the working fluid from between the tooth surfaces. In the internal gear pump,
The partition member has an inner peripheral surface including a sliding contact surface that is in sliding contact with the tooth tip of the inner gear, and an outer peripheral surface including a sliding contact surface that is in sliding contact with the tooth tip of the outer gear,
Between the tooth surfaces of the inner gear and the outer gear, a low pressure chamber is defined by an outer peripheral surface of the partition member and a tooth surface of the outer gear and connected to a drain port formed in the housing ,
The partition member has a first member having a sliding contact surface in sliding contact with a tooth tip of the inner gear, a sliding contact surface in sliding contact with a tooth tip of the outer gear, and the working fluid with respect to the first member. It is comprised from the 2nd member and 3rd member which are spaced apart along a distribution direction, and each between the 1st member and the 2nd member, and between the 1st member and the 3rd member Includes a seal member that seals leakage of working fluid from the high pressure side to the low pressure side through the tooth tips of the inner gear and the outer gear, and the low pressure chamber is located between the seal members. inscribed gear pump, characterized by that. The outer gear is cylindrical and has a plurality of inflow and outflow holes that allow the working fluid to flow into and out of the suction port and the discharge port while penetrating inner and outer peripheral surfaces.
2. The internal gear pump according to claim 1, wherein a concave portion to which the drain port is connected is formed on a sliding contact surface with which an outer peripheral surface of the outer gear is slidably contacted in the housing. An introduction groove into which a high-pressure working fluid is introduced is formed on the sliding contact surface on which the outer peripheral surface of the outer gear slides in the housing,
The internal gear pump according to claim 1, wherein the introduction groove includes a first introduction groove connected to the suction port and a second introduction groove connected to the discharge port.   The internal gear pump according to claim 3, wherein the first introduction groove and the second introduction groove have an asymmetric shape.