JP5314784B2 - Internal gear pump - Google Patents

Description

  The present invention relates to an internal gear pump having a plurality of discharge ports.

  In this type of internal gear pump, a ring-shaped internal gear having internal teeth is rotatably accommodated in an accommodation hole of the pump housing, and an external tooth having external teeth that mesh with the internal teeth of the internal gear. The tooth gear is eccentrically housed inside the internal gear, and the meshing gap between both teeth is formed on the bottom surface of the receiving hole as the sliding contact surface of the pump housing where the side surfaces of both gears are in sliding contact. Opening the suction port in communication with the increasing suction area space, communicating with the discharge area space in which the meshing gap between both teeth is reduced, and opening the two discharge ports apart in the rotational direction of both gears Form. Of the two discharge ports, one discharge port (described as the third discharge port in Patent Document 1) located on the rear side in the rotational direction of both gears is a low pressure for lubrication and cooling. The other discharge port (described as the second discharge port in Patent Document 1) that communicates with the hydraulic circuit and is located on the front side in the rotational direction of both gears from one discharge port is a shift control valve or the like. It communicates with a high-pressure hydraulic circuit so that a single pump can supply hydraulic oil of different pressures to two supply destinations.

JP 2001-123967 A (paragraph numbers 0028, 0032, 0033, FIG. 1)

  However, in such a conventional internal gear pump, one discharge port located on the rear side in the rotation direction of both gears is set to a low pressure, and the other discharge port located on the front side in the rotation direction of both gears is set to a high pressure. For this reason, at the location where one discharge port that becomes low pressure opens, the pressure that acts on the inner peripheral side of the internal gear leaks from the other discharge port that becomes high pressure to the outer peripheral side via the side surface of the internal gear. Therefore, the pressure acting on the outer peripheral side of the internal gear is higher, and the internal gear is on the side where the suction port is located by the acting force based on the pressure difference between the pressure acting on the inner peripheral side and the pressure acting on the outer peripheral side. Is pressed toward the inner peripheral surface of the collection hole. The external gear is arranged on the inner peripheral surface of the housing hole toward the side where the suction port is located by the acting force based on the pressure difference between the pressure of the suction port acting on the outer peripheral side and the pressure of the other discharge port. Pressed. Therefore, since the internal gear is pressed in the same direction as the external gear, the meshing position between the internal gear and the external gear is more in the rotational direction than the optimal meshing position in the vicinity of the position where the meshing clearance between the two teeth is minimized. It may shift to the front side, the meshing of both teeth may become unstable, and the meshing position may move to the adjacent tooth with slight pressure fluctuations. Noise and vibration will occur with repeated contact and non-contact of both teeth. There was a problem that increased.

  An object of the present invention is to provide an internal gear pump capable of reducing noise and vibration by supplying hydraulic oils having different pressures to two supply destinations with one pump and meshing internal teeth and external teeth at an optimal meshing position. Is to provide.

In order to achieve this problem, the present invention has taken the following measures. That is,
A ring-shaped internal gear having internal teeth is rotatably accommodated in the housing hole of the pump housing, and the external gear having external teeth that are in mesh with the internal teeth of the internal gear is eccentric to the internal gear. The external gear engages with the rotating shaft and is driven to rotate. Between the two gears, a suction area space is formed in a region where the meshing gap between the two teeth increases due to the rotation of the two gears. A discharge area space is formed in an area where the meshing gap between both teeth is reduced by rotation, and the sliding surface of the pump housing where the side surfaces of both gears accommodated in the accommodation hole are in sliding contact communicates with the suction area space. And two discharge ports that communicate with the discharge area space and are spaced apart in the rotation direction of both gears. The two discharge ports are one discharge port located on the rear side in the rotation direction of both gears. The pressure of the two gears Internal gear pump, characterized in that communicating the pressure of the other discharge ports located at the front side in the direction to the low pressure side of the pressure of the low pressure of one of the discharge port is it.

  As described above in detail, in the invention described in claim 1, the two discharge ports communicate the pressure of one discharge port located on the rear side in the rotation direction of both gears to the high pressure side, and rotate both gears. The pressure of the other discharge port located on the front side in the direction is communicated to the low pressure side, which is lower than the pressure of one discharge port. For this reason, at the location where one discharge port communicating with the high pressure side opens, the pressure acting on the inner peripheral side of the internal gear is changed from the one discharge port communicating with the high pressure side to the outer periphery via the side surface of the internal gear. The internal gear has an acting force based on the pressure difference between the pressure acting on the inner peripheral side and the pressure acting on the outer peripheral side, while the pressure on the other side of the internal gear is higher than the pressure acting on the outer peripheral side of the internal gear. It is pressed against the inner peripheral surface of the collection hole toward the side where the discharge port is located. The external gear is arranged on the inner peripheral surface of the housing hole toward the side where the suction port is located by the acting force based on the pressure difference between the pressure of the suction port acting on the outer peripheral side and the pressure of the other discharge port. Pressed. Therefore, since the internal gear is pressed in the opposite direction opposite to the direction in which the external gear is pressed, the meshing position between the internal teeth and the external teeth is in the vicinity of the position where the meshing gap between both teeth is minimized. It can be stably positioned at the optimum meshing position, and noise and vibration can be reduced.

It is a longitudinal cross-sectional view of the internal gear pump which showed one Embodiment of this invention. It is sectional drawing along line AA of FIG. It is a characteristic view which shows the measurement result of pump performance.

Hereinafter, an embodiment of the present invention applied to a pump of an automatic transmission of an automobile will be described with reference to the drawings.
1 and 2, reference numeral 1 denotes a pump body, which has a bottomed receiving hole 2 formed at one end surface. A lid member 3 is fastened to the pump body 1 with a bolt member 4 so as to close the opening of the accommodation hole 2. The pump main body 1 and the lid member 3 constitute a pump housing 5. Reference numeral 6 denotes a ring-shaped internal gear, which has ten internal teeth 6 </ b> A and is rotatably accommodated in the accommodation hole 2. Reference numeral 7 denotes an external gear, which has nine external teeth 7A that are in mesh with the internal teeth 6A, and is housed eccentrically in the internal gear 6. One side surface in the axial direction of both gears 6, 7 is on the bottom surface 2 A of the bottomed receiving hole 2, and the other side surface in the axial direction of both gears 6, 7 is a part of the lid member 3 that closes the opening of the housing hole 2. Each side surface 3A can be slidably contacted. The bottom surface 2A of the collection hole 2 and one side surface 3A of the lid member 3 are used as the sliding contact surface of the pump housing 5 where the side surfaces of both gears 6 and 7 are in sliding contact. The external gear 7 has a through hole 7B formed in the center in the axial direction, and a cylindrical bearing bush member 8 made of a copper alloy is press-fitted and fixed in the through hole 7B so as to be excellent in lubricity and difficult to seize. Yes. Further, recesses 7C are formed at two locations facing the through hole 7B in the radial direction.

  Reference numeral 9 denotes a stator shaft as a fixed shaft, which is fixed to the lid member 3 of the pump housing 5, has a tip portion extending through the pump body 1, and a bearing bush member 8 is externally fitted so as to be slidable. The gear 7 is rotatably supported. Reference numeral 10 denotes an oil pump drive hub as a drive shaft, which is formed in a cylindrical shape, and is rotatably supported on the pump body 1 of the pump housing 5 via the bearing bush member 11 concentrically with the external gear 7. The convex portions 10A are formed to project in the axial direction at two locations facing each other in the radial direction, and the convex portions 10A are inserted into the concave portions 7C of the external gear 7 to rotationally drive the external gear 7.

  S is a suction area space, P is a discharge area space, and is provided between the gears 6 and 7, respectively. The suction area space S is formed in a region where the meshing clearance between the teeth 6A and 7A increases as the gears 6 and 7 rotate. doing. Further, the discharge area space P is formed in an area where the meshing gap between the teeth 6A and 7A is reduced by the rotation of the gears 6 and 7. Reference numerals 12A and 12B denote suction ports that communicate with the suction area space S. The suction port 12A on the pump body 1 side that communicates with the suction area space S from one side in the axial direction is formed in the bottom surface 2A of the housing hole 2 so as to be recessed. The suction port 12B on the side of the lid member 3 communicating with the suction area space S from the other side in the axial direction is formed in a recessed manner on one side surface 3A of the lid member 3 and opened. Reference numeral 13 denotes a suction passage formed in the pump body 1, which is connected to the suction ports 12A and 12B and distributes oil sucked from a tank (not shown).

  14A, 14B and 15A, 15B are two discharge ports that communicate with the discharge area space P and are spaced apart in the rotational direction B of both gears 6, 7, and are located on the rear side in the rotational direction B of both gears 6, 7. The discharge ports 14A and 14B and the other discharge ports 15A and 15B located on the front side in the rotation direction B are formed. One discharge port 14A, 14B is connected to a first discharge flow path 16 formed in the pump body 1, and communicates with the high pressure hydraulic circuit such as a shift control valve from the first discharge flow path 16 to increase the pressure. One discharge port 14A on the pump body 1 side that communicates with the space P from one side in the axial direction is formed by opening a recess in the bottom surface 2A of the receiving hole 2, and a lid that communicates with the discharge region space P from the other side in the axial direction. One discharge port 14 </ b> B on the side of the member 3 is formed in a recessed manner on one side surface 3 </ b> A of the lid member 3 and opened.

  The other discharge ports 15A and 15B are connected to a second discharge flow path 17 formed in the pump body 1, and communicate with a low pressure hydraulic circuit for lubrication and cooling from the second discharge flow path 17 to discharge one of the discharge ports. The other discharge port 15A on the pump main body 1 side communicating with the discharge region space P from one side in the axial direction is formed in a recess in the bottom surface 2A of the receiving hole 2 and opened. The other discharge port 15 </ b> B on the lid member 3 side communicating with the space P from the other side in the axial direction is formed in a recessed manner on one side surface 3 </ b> A of the lid member 3.

Next, the operation of this configuration will be described.
When the external gear 7 is rotationally driven by the oil pump drive hub 10, the internal gear 6 that is in mesh with the external gear 7 is rotationally driven, and the oil in the suction passage 13 is sucked through the suction ports 12A and 12B through the suction area S. The oil discharged into the discharge area space P and discharged from the one discharge port 14A, 14B and the other discharge port 15A, 15B, and the oil discharged to the one discharge port 14A, 14B is the first discharge flow path 16. And is supplied to a high-pressure hydraulic circuit such as a shift control valve. The oil discharged to the other discharge ports 15A and 15B flows through the second discharge passage 17 and is supplied to a low pressure hydraulic circuit for lubrication and cooling.

  With this operation, the pressure of one discharge port 14A, 14B located on the rear side in the rotation direction B of both gears 6, 7 is increased, and the other discharge located on the front side in the rotation direction B of both gears 6, 7 is performed. The pressure of the ports 15A and 15B is set to be lower than the pressure of one of the discharge ports 14A and 14B. For this reason, in the location where one discharge port 14A, 14B which becomes high pressure opens, the pressure which acts on the inner peripheral side of internal gear 6 is the side of internal gear 6 from one discharge port 14A, 14B which becomes high pressure. The pressure is higher than the pressure acting on the outer peripheral side of the internal gear 6 through leakage to the outer peripheral side, and the internal gear 6 is based on the pressure difference between the pressure acting on the inner peripheral side and the pressure acting on the outer peripheral side. With one force, the other discharge port 14A, 14B, 15A, 15B is pressed to the inner peripheral surface of the collection hole 2 as shown by the arrow C toward the left side in FIG. In addition, the external gear 7 is a suction port 12A, 12B with an action force based on a pressure difference between the pressure of the suction ports 12A, 12B acting on the outer peripheral side and the pressure of the other discharge port 14A, 14B, 15A, 15B. Is pressed against the inner peripheral surface of the collection hole 2 as indicated by the arrow D toward the right side of FIG. Therefore, since the internal gear 6 is pressed in the opposite direction opposite to the direction in which the external gear 7 is pressed, the meshing position between the internal teeth 6A and the external teeth 7A is the meshing gap between both the teeth 6A and 7A. It can be stably positioned at the optimum meshing position E in the vicinity of the minimum position, and noise and vibration can be reduced.

  The external gear 7 includes a bearing bush member 8, the pump housing 5 includes a stator shaft 9 as a fixed shaft different from the oil pump drive hub 10 as a drive shaft, and the external gear 7 is connected to the bearing bush. The shaft 8 is rotatably supported on the stator shaft 9 of the pump housing 5 via the member 8. For this reason, since the external gear 7 can be pivotally supported while suppressing rattling in the radial direction, the external gear 7 can be positioned more stably at the optimal meshing position E, and the internal gear 6 can be positioned at the optimal meshing position E. Therefore, noise and vibration can be further reduced.

  Now, the tooth shape module 7.36 of the internal gear 6 and the external gear 7, the number of teeth of the internal gear 6, the number of teeth of the external gear 7, the displacement of 14 cc / rev, the rotation of both gears 6 and 7 The pressure at one discharge port 14A, 14B located on the rear side in the direction B is 2.0 MPa for high pressure, and the pressure on the other discharge port 15A, 15B located on the front side in the rotation direction B for both gears 6, 7 is low. When the noise value was measured with an internal gear pump corresponding to one embodiment of the present invention, which was 0.5 MPa, the rotation speed was 1000 rpm, 72.7 dB, the rotation speed 1500 rpm, 74.3 dB, and the rotation speed 2000 rpm. They were 3 dB, 75.4 dB at a rotational speed of 2500 rpm, 79.8 dB at a rotational speed of 3000 rpm, and 83.2 dB at a rotational speed of 3500 rpm.

  However, in such specifications, the pressure of one discharge port 14A, 14B located on the rear side in the rotational direction B of both gears 6, 7 is set to 0.5 MPa, which is a low pressure, and the front side in the rotational direction B of both gears 6, 7. When the noise value was measured with a conventional internal gear pump in which the pressure of the other discharge port 15A, 15B positioned was 2.0 MPa, which was a high pressure, 73.6 dB at a rotation speed of 1000 rpm, 75.4 dB at a rotation speed of 1500 rpm, The rotation speed was 81.8 dB at 2000 rpm, 82.5 dB at 2500 rpm, 83 dB at 3000 rpm, and 90.7 dB at 3500 rpm.

  These measurement results are shown in FIG. 3, and the noise value of the internal gear pump corresponding to the above-described one embodiment is indicated by the line F. The noise value indicated by the line G corresponding to the above-described conventional internal gear pump is shown in FIG. A value lower than the value at any number of revolutions was measured.

  In one embodiment, the pump housing 5 is constituted by the pump body 1 and the lid member 3 having the bottomed housing hole 2 formed therein, but the both ends of the pump body and the housing hole that are formed through the housing hole are closed. As such, the pump housing may be configured with lid members provided on both sides of the pump body. Also, suction ports 12A and 12B and discharge ports 14A and 14B are provided on the bottom surface 2A (sliding contact surface) of the housing hole 2 where both side surfaces of both gears 6 and 7 are in sliding contact and one side surface 3A (sliding contact surface) of the lid member 3, respectively. 15A and 15B are opened, but it is needless to say that the suction port and the discharge port may be opened on any one of the sliding contact surfaces.

2: Housing hole 2A: Bottom surface (sliding contact surface)
3A: One side surface (sliding contact surface)
5: Pump housing 6: Internal gear 6A: Internal gear 7: External gear 7A: External gear 10: Oil pump drive hub (drive shaft)
12A, 12B: Suction port 14A, 14B: One discharge port 15A, 15B: The other discharge port S: Suction area space P: Discharge area space

Claims (1)

  A ring-shaped internal gear having internal teeth is rotatably accommodated in the housing hole of the pump housing, and the external gear having external teeth that are in mesh with the internal teeth of the internal gear is eccentric to the internal gear. The external gear engages with the rotating shaft and is driven to rotate. Between the two gears, a suction area space is formed in a region where the meshing gap between the two teeth increases due to the rotation of the two gears. A discharge area space is formed in an area where the meshing gap between both teeth is reduced by rotation, and the sliding surface of the pump housing where the side surfaces of both gears accommodated in the accommodation hole are in sliding contact communicates with the suction area space. And two discharge ports that communicate with the discharge area space and are spaced apart in the rotation direction of both gears. The two discharge ports are one discharge port located on the rear side in the rotation direction of both gears. The pressure of the two gears Internal gear pump, characterized in that the pressure of the other discharge ports located at the front side in the direction from the pressure of one of the discharge port in communication with the low pressure side of the low pressure.

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