JP2015040491A - Gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear pump in which the occurrence of cavitation can be successfully suppressed.SOLUTION: A suction port groove 22 and a discharge port groove 31 are each formed in at least one member out of a pump body 10 and a pump cover 20. In the groove bottom face of the suction port groove 22, an intermediate partition wall 60 for partitioning the suction port groove 22 into an outer periphery side groove part 61 and an inner periphery side groove part 62 is formed. In an area of the intermediate partition wall 60 near a terminal end wall part 27 of the suction port groove 22, a communication part 63 for communicating the outer periphery side groove part 61 and the inner periphery side groove part 62 with each other is formed. Oil which is made high in pressure by receiving the action of centrifugal force in a gear chamber 50 between an internal tooth 41 and an external tooth 46, flows in the outer periphery side groove part 61. The oil then flows from the terminal end wall part 27 through the communication part 63 into a gear chamber 50 which is configured between an internal tooth 41 and an external tooth 46 and at a position closest to the terminal end wall part 27 on the side of the suction port groove 22.

Description

  The present invention relates to an internal gear type gear pump used for an automatic transmission, a continuously variable transmission, or the like.

In the internal gear type gear pump, a rotor built-in chamber constituted by a pump body and a pump cover is provided between an outer rotor having a plurality of internal teeth (sometimes referred to as a driven gear) and the internal teeth. An inner rotor (also referred to as a drive gear) having outer teeth that constitute a gear chamber and that are driven to rotate while meshing with the inner teeth is disposed. Further, there is known a structure in which a suction port groove constituting a suction port and a discharge port groove constituting a discharge port are respectively formed in at least one member of the pump body and the pump cover. ing.
In this type of gear pump, when the inner rotor is rotationally driven at a high speed, the amount of oil sucked into the gear chamber between the inner teeth and the outer teeth from the suction port groove tends to be insufficient. Then, cavitation occurs due to insufficient suction of oil into the gear chamber between the inner teeth and the outer teeth, and as a result, the amount of oil discharged decreases, hydraulic vibration, abnormal noise, and the like occur.
In order to suppress the occurrence of cavitation in the gear chamber of the gear pump, for example, a gear pump disclosed in Patent Document 1 is known.
In this case, there is a step extending in the rotation direction of the pump gear at the bottom of the suction port provided in the pump body and the pump cover for accommodating the pump gear. The depth of the bottom on the inner peripheral side from the step of the suction port is set to be deeper than the depth of the bottom on the outer peripheral side of the step of the suction port.

JP 2005-76542 A

  By the way, in the gear pump disclosed in Patent Document 1, bubbles in the sucked oil are collected on the inner peripheral side of the suction port, but some of the bubbles remain in the gear chamber between the inner teeth and the outer teeth. . Thereafter, since the oil is discharged into the discharge port in a state where bubbles are mixed, it is assumed that the oil discharge amount is reduced.

  In view of the above problems, an object of the present invention is to provide a gear pump that can satisfactorily suppress the occurrence of cavitation.

  In order to solve the above problems, a gear pump according to a first aspect of the present invention includes an outer rotor having a plurality of internal teeth in a rotor built-in chamber constituted by a pump body and a pump cover, and the internal teeth. And an inner rotor having outer teeth that are engaged with the inner teeth and driven to rotate, and are arranged for at least one of the pump body and the pump cover. A gear pump in which a suction port groove that constitutes a suction port and a discharge port groove that constitutes a discharge port are respectively formed, and the suction port groove is formed on the bottom surface of the suction port groove with the outer peripheral groove portion. An intermediate partition wall that is divided into a peripheral groove portion is formed, and the outer peripheral groove portion and the inner peripheral groove portion are communicated with a portion of the intermediate partition wall that is close to the end wall portion of the suction port groove. A communicating portion is formed, and oil that has been pressurized by the action of centrifugal force in the gear chamber between the inner teeth and the outer teeth flows through the outer peripheral groove portion, and passes through the communicating portion from the terminal wall portion. The oil is configured to flow into a gear chamber between the inner teeth and the outer teeth that are configured at the closest position on the suction port groove side to increase the pressure of the oil.

According to the first invention, when the gear pump is operated, a part of the oil whose pressure is increased by the action of centrifugal force in the gear chamber between the inner teeth and the outer teeth is partitioned by the intermediate partition wall of the suction port groove. The oil flows into the outer peripheral groove portion, whereby the oil in the outer peripheral groove portion is increased in pressure.
The oil whose pressure has been increased in the outer peripheral side groove portion flows into the gear chamber between the inner teeth and the outer teeth that are configured at the closest position on the suction port groove side from the terminal wall portion of the suction port groove through the communication portion.
As a result, it is possible to increase the pressure of the oil in the gear chamber between the inner teeth and the outer teeth that are located at the closest position on the suction port groove side from the end wall portion of the suction port groove.
With the subsequent operation of the gear pump, the oil in the high pressure gear chamber is discharged into the discharge port groove.
As described above, by increasing the pressure of the oil in the gear chamber, the occurrence of cavitation can be satisfactorily suppressed.
As a result, it is possible to suppress a decrease in oil discharge amount, hydraulic vibration, abnormal noise, and the like caused by cavitation.

  A gear pump according to a second aspect of the present invention is the gear pump according to the first aspect, wherein a base end portion of the intermediate partition wall is connected to an outer peripheral side wall portion of the suction port groove or a start end wall portion of the suction port groove. It is characterized by being.

  According to the second invention, since the base end portion of the intermediate partition wall is connected to the outer peripheral side wall portion of the suction port groove or the start end wall portion of the suction port groove, the intermediate partition of the suction port groove is operated when the gear pump is operated. The high-pressure oil in the outer peripheral groove section partitioned by the wall can be prevented from flowing out from the base end portion of the intermediate partition wall, and can be kept in a high-pressure state.

  A gear pump according to a third aspect of the present invention is the gear pump according to the first aspect, wherein the intermediate partition wall includes a first wall portion extending from a terminal wall portion of the suction port groove, and the first wall portion. It has the 2nd wall part formed through the communicating part between the extension end parts of the wall part, It is characterized by the above-mentioned.

  According to the third aspect of the present invention, the first wall portion extended from the terminal wall portion of the suction port groove and the extended end portion of the first wall portion are formed with a communication portion therebetween. By setting the intermediate partition wall with two wall portions, the arrangement position of the communication portion that communicates the outer peripheral side groove portion and the inner peripheral side groove portion of the suction port groove is set to a desired position. Can do.

  A gear pump according to a fourth aspect of the present invention is the gear pump according to the third aspect, wherein the base end portion of the second wall portion of the intermediate partition wall is the outer peripheral side wall portion of the suction port groove or the suction port groove. It is characterized by being connected to the starting end wall.

  According to the fourth invention, the base end portion of the second wall portion of the intermediate partition wall is connected to the outer peripheral side wall portion of the suction port groove or the start end wall portion of the suction port groove. The high pressure oil in the outer peripheral side groove portion defined by the second wall portion of the intermediate partition wall of the suction port groove can be prevented from flowing out from the base end portion of the second wall portion. Can be kept in a state.

  According to the present invention, the occurrence of cavitation can be satisfactorily suppressed.

It is a front view which shows the state by which the outer rotor and the inner rotor were integrated in the rotor incorporation chamber of the gear pump which concerns on Example 1 of this invention. It is sectional drawing of the gear pump which similarly follows the II-II line of FIG. It is a perspective view which similarly shows a pump cover. Similarly, it is a front view showing a state in which the suction port groove is partitioned into an outer peripheral groove portion and an inner peripheral groove portion by an intermediate partition wall and communicated by a communication portion. It is explanatory drawing which shows the state in which the oil in a gear chamber similarly becomes high pressure. The suction port groove of the gear pump according to the second embodiment of the present invention is divided into an outer peripheral groove portion and an inner peripheral groove portion by the first wall portion and the second wall portion constituting the intermediate partition wall and communicated by the communication portion. It is a front view which shows the state. A suction port groove of a gear pump according to Embodiment 3 of the present invention is partitioned into an outer peripheral groove portion and an inner peripheral groove portion by a first wall portion and a second wall portion constituting an intermediate partition wall, and communicated by a communication portion. It is a front view which shows the state.

  A mode for carrying out the present invention will be described according to an embodiment.

A gear pump according to Embodiment 1 of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the gear pump includes a pump body 10, a pump cover 20, an outer rotor 40, an inner rotor 45, and a drive shaft 1.
The pump body 10 includes a disc-shaped bottom wall 11 and a peripheral wall 13 formed in a cylindrical shape along the peripheral edge of the bottom wall 11, and a recess that opens to one end side by the bottom wall 11 and the peripheral wall 13. 14 is formed.
Further, the bottom wall 11 is formed with a through hole 12 having a center at a position eccentric from the center by an amount corresponding to the amount of eccentricity A between the outer rotor 40 and the inner rotor 45 described in detail below.
The pump cover 20 is attached to the end face of the peripheral wall 13 of the pump body 10 in a sealing manner by bolts or the like (not shown), and the recess 14 of the pump body 10 is closed to constitute the rotor built-in chamber 15.

As shown in FIGS. 1 and 2, the outer rotor 40 is rotatably fitted in the rotor assembly chamber 15. A plurality of internal teeth 41 are formed in the circumferential direction of the inner peripheral surface of the outer rotor 40.
The inner rotor 45 is incorporated into the inner peripheral surface of the outer rotor 40 in an eccentric state by an eccentric amount A, and a plurality of external teeth 46 that mesh with the plurality of inner teeth 41 of the outer rotor 40 are formed in the circumferential direction of the outer peripheral surface. Yes. An oil chamber 50 is formed between the inner teeth 41 of the outer rotor 40 and the outer teeth 46 of the inner rotor 45 so as to be able to expand and contract.
A non-circular shaft hole 47 is formed in the center portion of the inner rotor 45, and the tip shaft portion 2 of the drive shaft 1 is fitted and inserted into the shaft hole 47 through the through hole 12 of the pump body 10 so that torque can be transmitted.
In the first embodiment, a flat surface 3 that is chamfered in the axial direction of the outer peripheral surface of the tip shaft portion 2 of the drive shaft 1 is formed, and the inner peripheral surface of the shaft hole 47 has a shaft at a position facing the flat surface 3. A flat portion 48 is formed so as to form an arc string of the hole 47.
Then, the inner rotor 45 rotates by receiving torque transmission from the drive shaft 1, so that the outer rotor 40 follows and rotates with the outer teeth 46 of the inner rotor 45 meshing with the inner teeth 41 of the outer rotor 40. Eggplant.

As shown in FIG. 2, at least one member of the pump body 10 and the pump cover 20, in the first embodiment, both the pump body 10 and the pump cover 20 have a front shape that constitutes a suction port. A suction port groove 22 having an arc shape and a discharge port groove 31 having a front surface forming an arc shape forming an arc shape are formed.
The suction port groove 22 is connected to a suction system path (not shown), and the discharge port groove 31 is connected to a discharge system path (not shown).

As shown in FIG. 3 and FIG. 4, an intermediate partition wall 60 that partitions the suction port groove 22 into an outer peripheral groove portion 61 and an inner peripheral groove portion 62 is formed on the groove bottom surface of the suction port groove 22.
In addition, a communication portion 63 that connects the outer peripheral side groove portion 61 and the inner peripheral side groove portion 62 is formed in a portion of the intermediate partition wall 60 near the end wall portion 27 of the suction port groove 22.
Then, a part of the oil whose pressure is increased by the action of centrifugal force in the gear chamber 50 between the inner teeth 41 and the outer teeth 46 flows into the outer circumferential groove portion 61 and passes through the communication portion 63 to the end wall portion. 27 is configured to increase the pressure of the oil by flowing into the gear chamber 50 between the inner teeth 41 and the outer teeth 46 that are located closest to the suction port groove 22 side.

  In the first embodiment, the intermediate partition wall 60 is an outer peripheral side wall of the suction port groove 22 that is separated from the end wall portion 27 of the suction port groove 22 by a distance corresponding to one pitch of the plurality of internal teeth 41 or more. The portion 25 is connected to a portion of the base end portion 60a and extends from the base end portion 60a toward the terminal wall portion 27 of the suction port groove 22 in an arc shape. In the portion where the intermediate partition wall 60 is formed, the suction port groove 22 is divided into an outer peripheral groove portion 61 and an inner peripheral groove portion 62, and the extension end of the intermediate partition wall 60 and the end wall portion 27 are separated. A communication portion 63 is formed therebetween.

The gear pump according to the first embodiment is configured as described above.
Therefore, when the pump is operated, the torque of the drive shaft 1 is received and the inner rotor 45 is rotationally driven in the clockwise arrow P direction toward FIG. 1, and the outer rotor 40 is rotated following this. Then, the oil chamber 50 between the inner teeth 41 of the outer rotor 40 and the outer teeth 46 of the inner rotor 45 is expanded and contracted, so that the oil supplied to the suction port groove 22 is in contact with the inner teeth 41 of the outer rotor 40 and the inner rotor. The oil in the gear chamber 50 is discharged into the discharge port groove 31 after being sucked into the gear chamber 50 between the 45 outer teeth 46.

The oil flows in the vicinity of the end wall 27 of the suction port groove 22 when the pump is operated, as indicated by the arrows shown in FIG.
That is, when the low-pressure oil on the suction port groove 22 side is sucked into the gear chamber 50, the sucked oil flows to the outer peripheral side under the action of centrifugal force and is increased in pressure.
A part of the high-pressure oil flows into the outer peripheral side groove 61 defined by the intermediate partition wall 60 of the suction port groove 22. The high-pressure oil that has flowed into the outer circumferential groove 61 flows toward the end wall 27 of the suction port groove 22, and the oil in the vicinity of the end wall 27 of the suction port groove 22 is increased in pressure.
For this reason, the oil in the gear chamber 50 between the inner teeth 41 and the outer teeth 46 configured at the closest position on the suction port groove 22 side from the terminal wall portion 27 of the suction port groove 22 is increased in pressure. As a result, the occurrence of cavitation in the oil in the gear chamber 50 can be satisfactorily suppressed.
As a result, it is possible to suppress a decrease in oil discharge amount, hydraulic vibration, abnormal noise, and the like caused by cavitation.

Next, a gear pump according to Embodiment 2 of the present invention will be described with reference to FIG.
As shown in FIG. 6, in the second embodiment, an intermediate partition wall 160 that is formed on the bottom surface of the suction port groove 122 and divides the suction port groove 122 into an outer circumferential groove 161 and an inner circumferential groove 162. A second wall 160b formed between the first wall 160b extending from the end wall 127 of the suction port groove 122 and the extending end of the first wall 160b with a communication portion 163 therebetween. And a wall portion 160c.
Further, the base end portion 160 a of the intermediate partition wall 160 is separated from the terminal wall portion 127 of the suction port groove 122 by a distance corresponding to one pitch of the plurality of internal teeth 41 or more than that. The outer peripheral side wall 25 is connected to the portion.
Since other configurations of the second embodiment are configured in the same manner as the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

Therefore, also in the second embodiment, as in the first embodiment, the oil flows in the vicinity of the end wall portion 127 of the suction port groove 122 when the pump is operated, as indicated by the arrows shown in FIG.
That is, when the low-pressure oil on the suction port groove 122 side is sucked into the gear chamber 50, the sucked oil flows to the outer peripheral side under the action of centrifugal force and is increased in pressure.
A part of the oil whose pressure has been increased flows to the outer circumferential groove 161 defined by the first and second walls 160b and 160c constituting the intermediate partition wall 160 of the suction port groove 122. Then, the high-pressure oil that has flowed into the outer circumferential groove 161 flows toward the inner circumferential groove 162 through the communication portion 163, so that the oil in the vicinity of the end wall 127 of the suction port groove 122 is pressurized.
For this reason, the oil in the gear chamber 50 between the inner teeth 41 and the outer teeth 46 that are located at the closest position on the suction port groove 122 side from the terminal wall portion 127 of the suction port groove 122 is increased in pressure. As a result, the occurrence of cavitation in the oil in the gear chamber 50 can be satisfactorily suppressed.
As a result, it is possible to suppress a decrease in oil discharge amount, hydraulic vibration, abnormal noise, and the like caused by cavitation.

  In particular, in the second embodiment, the communication portion 163 is provided between the first wall portion 160b extending from the terminal wall portion 127 of the suction port groove 122 and the extending end portion of the first wall portion 160b. The intermediate partition wall 160 is configured to have the second wall portion 160c formed at a distance, so that the communication portion 163 that communicates the outer peripheral side groove portion 161 and the inner peripheral side groove portion 162 of the suction port groove 122 with each other. The arrangement position can be set to a desired position.

Next, a gear pump according to Embodiment 3 of the present invention will be described with reference to FIG.
As shown in FIG. 7, in the third embodiment, the intermediate partition wall 260 is connected to the start end wall portion 228 of the suction port groove 222 by a base end portion 260a, and the end of the suction port groove 222 is extended from the base end portion 260a. It is configured to extend in an arc shape toward the wall portion 227. In the portion where the intermediate partition wall 260 is formed, the suction port groove 222 is divided into an outer peripheral groove portion 261 and an inner peripheral groove portion 262, and the extension end of the intermediate partition wall 260 and the end wall portion 227 are separated from each other. A communication portion 263 is formed therebetween.
Since other configurations of the third embodiment are configured in the same manner as in the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

Therefore, in the third embodiment, when a part of the low-pressure oil on the suction port groove 222 side is sucked into the plurality of gear chambers 50 when the pump is operated, the oil sucked into the gear chambers 50 is sucked. Under the action of centrifugal force, it flows to the outer peripheral side and becomes high pressure.
A part of the high-pressure oil flows into the outer peripheral side groove portion 261 defined by the intermediate partition wall 260 of the suction port groove 222. Then, the high-pressure oil that has flowed into the outer circumferential groove 261 flows toward the inner circumferential groove 262 through the communication portion 263, so that the oil in the vicinity of the end wall portion 227 of the suction port groove 222 is increased in pressure.
For this reason, the pressure in the oil in the gear chamber 50 between the inner teeth 41 and the outer teeth 46 configured at the closest position on the suction port groove 222 side from the end wall portion 227 of the suction port groove 222 is increased. As a result, the occurrence of cavitation in the oil in the gear chamber 50 can be satisfactorily suppressed.
As a result, it is possible to suppress a decrease in oil discharge amount, hydraulic vibration, abnormal noise, and the like caused by cavitation.

In addition, this invention is not limited to the said Example 1, In the range which does not deviate from the summary of this invention, it can implement with a various form.
For example, in the second embodiment, the base end portion 160a of the intermediate partition wall 160 has a distance corresponding to one pitch of the plurality of internal teeth 41 from the terminal wall portion 127 of the suction port groove 122, or a distance greater than that. Although the case where it is connected to the portion of the outer peripheral side wall portion 25 of the suction port groove 22 is illustrated as an example, the base end portion 160 a of the intermediate partition wall 160 may be connected to the start end wall portion of the suction port groove 22.
In the first to third embodiments, the suction port groove 22 (122, 222) that constitutes the suction port and the discharge port groove 31 that constitutes the discharge port for both the pump body 10 and the pump cover 20 are provided. In the case where the suction port groove 22 (122, 222) and the discharge port groove 31 are formed for one member of the pump body 10 and the pump cover 20, respectively. Can also implement this invention.

DESCRIPTION OF SYMBOLS 10 Pump body 15 Rotor built-in chamber 20 Pump cover 22 Suction port groove 25 Outer peripheral side wall part 26 Inner peripheral side wall part 27 Terminal wall part 31 Discharge port groove 40 Outer rotor 41 Inner tooth 45 Inner rotor 46 Outer tooth 50 Gear chamber 60 Intermediate partition wall 61 Outer peripheral side groove part 62 Inner peripheral side groove part 63 Communication part

Claims (4)

A gear chamber is formed between the inner rotor and the outer rotor having a plurality of inner teeth with respect to the rotor built-in chamber constituted by the pump body and the pump cover, and is rotated and engaged with the inner teeth. An inner rotor having an outer tooth, and a suction port groove constituting a suction port and a discharge port groove constituting a discharge port for at least one member of the pump body and the pump cover; Are respectively formed gear pumps,
An intermediate partition wall that divides the suction port groove into an outer peripheral groove portion and an inner peripheral groove portion is formed on the groove bottom surface of the suction port groove,
A portion of the intermediate partition wall near the end wall portion of the suction port groove is formed with a communication portion that communicates the outer peripheral groove portion and the inner peripheral groove portion,
Oil that has been increased in pressure by the action of centrifugal force in the gear chamber between the inner teeth and the outer teeth flows through the outer peripheral groove portion and through the communication portion from the terminal wall portion to the suction port groove side. A gear pump characterized in that the pressure of the oil is increased by flowing into a gear chamber between the inner teeth and the outer teeth configured at the closest positions. The gear pump according to claim 1,
A gear pump, wherein a base end portion of the intermediate partition wall is connected to an outer peripheral side wall portion of the suction port groove or a start end wall portion of the suction port groove. The gear pump according to claim 1,
The intermediate partition wall is a second wall formed with a communication portion between the first wall portion extended from the terminal wall portion of the suction port groove and the extended end portion of the first wall portion. And a wall pump. The gear pump according to claim 3, wherein
A gear pump, wherein a base end portion of the second wall portion of the intermediate partition wall is connected to an outer peripheral side wall portion of the suction port groove or a start end wall portion of the suction port groove.

Images