JP3714821B2 - Internal gear pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal gear pump, and more particularly to an internal gear pump suitable for use in a pump for an automatic transmission of an automobile.
[0002]
[Prior art]
In the conventional internal gear pump, the internal gear and the external gear are housed in a housing recess (gear pocket) opened in one end surface of the pump housing, and the internal gear and the external gear are placed on one end surface of the pump housing so as to close the opening of the housing recess. A lid member (pump cover) is provided to be installed with one end face in contact. The bottom of the housing recess where the axial side surfaces of the internal gear and the external gear are in sliding contact with each other is arranged to open from the side surface in the axial direction of both gears to the suction region of the pump chamber formed between the gears. An arc-shaped suction port smaller in diameter than the inner diameter of the pump housing is formed in a recess, and the suction port communicates with the suction passage at the bottom thereof, and the suction passage bypasses the housing recess and is one end surface of the pump housing on the radially outer side of the housing recess The pumping housing has wall portions remaining between the inner peripheral surface of the housing recess and the suction port, and between the bottom surface of the housing recess and the suction channel. Also, a suction port (oil chamber) and a suction path that open from the other side in the axial direction of both gears to the suction region of the pump chamber formed between the gears on one end surface of the lid member that contacts the one end surface of the pump housing An oil passage (oil chamber) communicating with the passageway is integrally formed as a depression. As a result, the rotation of both gears causes the oil in the suction passage to be sucked into the suction region of the pump chamber from both axial sides of both gears, thereby improving the suction efficiency. (For example, refer to Japanese Patent Application Laid-Open No. 8-200228).
[0003]
[Problems to be solved by the invention]
However, in such a conventional internal gear pump, a recess is formed in one end face of the lid member and is integrally formed with a suction port opened from the other side in the axial direction of both gears in a suction region of the pump chamber formed between both gears. Since the oil path formed in the depression is directly exposed to a minute gap (clearance) between the inner peripheral surface of the housing recess and the outer peripheral surface of the internal gear, dust (contaminant particles) in the oil flowing through the oil path, In particular, dust having a large particle size easily enters a minute gap between the inner circumferential surface of the housing recess and the outer peripheral surface of the internal gear, and the outer peripheral surface of the internal gear and the inner peripheral surface of the recess are abnormally worn or the internal gear is burned. There is a problem that sticking is likely to occur.
[0004]
The present invention provides an oil passage connected to a suction port that opens from the other axial side of both gears in a suction region of a pump chamber formed between both gears, an inner circumferential surface of a housing recess, an outer circumferential surface of an internal gear, An internal gear pump that is formed on a lid member so as not to be exposed to a minute gap between the internal gear and prevents abnormal wear on the outer peripheral surface of the internal gear and the inner peripheral surface of the housing recess and seizure of the internal gear. It is an issue.
[0005]
[Means for Solving the Problems]
Therefore, in the present invention, the pump housing in which the outer peripheral surface of the internal gear is slidably supported by the inner peripheral surface and an accommodation recess for accommodating the internal gear and the external gear meshing with the internal gear is opened at one end surface. And a lid member that is disposed so as to abut one end surface of the pump housing so as to close the opening of the housing recess, and on the bottom surface of the housing recess, both sides of the suction area of the pump chamber formed between the two gears are provided. An arc-shaped suction port having a diameter smaller than the inner diameter of the housing recess is formed so as to open from one side in the axial direction of the gear. The suction port communicates with the oil suction passage at the bottom, and the suction path bypasses the housing recess. A passage opening is opened on one end surface of the pump housing at a radially outer side than the housing recess, and the pump housing has walls between the inner peripheral surface of the housing recess and the passage port of the suction recess and between the bottom surface of the housing recess and the suction passage. Of the pump housing An arc-shaped suction port that opens from the other side in the axial direction of both gears is formed in the suction region of the pump chamber formed between the gears on one end surface of the lid member that contacts the end surface. An oil passage is formed in the lid member so as to bypass the opening of the housing recess and communicate with the inlet of the suction passage, and the inner surface of the housing recess faces the wall of the pump housing on one end surface of the lid member And a wall portion that covers a minute gap between the outer peripheral surface of the internal gear and the internal gear.
[0006]
According to the internal gear pump of the present invention, since the minute gap between the inner circumferential surface of the housing recess and the outer circumferential surface of the internal gear is covered by the wall portion of the lid member, the oil path is routed from the inlet of the suction path. When the oil sucked into the suction region of the pump chamber formed between the two gears from the other axial side of the two gears through the suction port of the flow lid member flows through the oil passage, the inner peripheral surface of the housing recess and the internal gear There is no direct contact with the minute gap between the outer peripheral surface. For this reason, it is possible to prevent dust in the oil flowing through the oil passage from entering a minute gap between the inner peripheral surface of the housing recess and the outer peripheral surface of the internal gear, and abnormalities in the outer peripheral surface of the internal gear and the inner surface of the housing recess Wear and seizure of the internal gear can be prevented.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
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.
Reference numeral 1 denotes a pump housing, in which an accommodation recess 4 is formed in one end surface 1A. The accommodation recess 4 accommodates an internal gear 2 and an external gear 3 meshing with the internal gear 2, and the inner peripheral surface 4A of the accommodation recess 4 is an internal tooth. The outer peripheral surface 2A of the gear 2 is slidably supported, and in order to partition the suction region and the discharge region of the pump chamber formed between the gears 2 and 3, a crescent shape from the bottom surface 4B of the housing recess 4 toward the opening. The partition portion 1B is projected. Reference numeral 5 denotes a lid member, which has its one end surface 5A abutted against one end surface 1A of the pump housing 1 and is fastened to the pump housing 1 with a plurality of bolts 6 so as to close the opening of the housing recess 4. Reference numeral 7 denotes a drive shaft, the tip of which is fitted to the external gear 3 so as to rotate the external gear 3.
[0008]
A suction port 8 and a discharge port 9 are formed in the bottom surface 4B of the housing recess 4 so as to be recessed, and the suction port 8 is formed in the suction region (left region in FIG. 2) of the pump chamber formed between the two gears 2 and 3. The discharge port 9 has a smaller diameter than the inner diameter of the housing recess 4 so as to open to the discharge region (the right region in FIG. 2) of the pump chamber formed between the two gears 2, 3 from one side in the axial direction of both the gears 2, 3. It is formed in a circular arc shape.
[0009]
An oil suction passage 10 communicates with the bottom of the suction port 8, and the suction passage 10 bypasses the accommodation recess 4 and opens a passage opening 10 </ b> A on one end face 1 </ b> A of the pump housing 1 on the outer side in the radial direction than the accommodation recess 4. By bypassing the suction passage 10, a wall portion 1 C is provided between the inner peripheral surface 4 A of the housing recess 4 of the pump housing 1 and the passage opening 10 A of the suction passage 10, and between the bottom surface 4 B of the housing recess 4 and the suction passage 10. Each of the walls 1D remains.
[0010]
An oil discharge passage 11 communicates with the bottom of the discharge port 9, and the discharge passage 11 bypasses the housing recess 4 and opens a passage port 11 </ b> A on the one end surface 1 </ b> A of the pump housing 1 on the outer side in the radial direction than the housing recess 4. As a result of the bypass of the discharge passage 11, a wall portion 1E is provided between the inner peripheral surface 4A of the housing recess 4 of the pump housing 1 and the passage port 11A of the discharge passage 11, and between the bottom surface 4B of the housing recess 4 and the discharge passage 11. Each has a wall portion (not shown) remaining.
[0011]
On one end surface 5A of the lid member 5, an arcuate suction port 12 having substantially the same shape facing the suction port 8 formed in the bottom surface 4B of the housing recess 4 and substantially the same facing the discharge port 9 is provided. An arc-shaped discharge port 13 is formed in a recessed shape, the suction port 12 is in the suction region of the pump chamber formed between the two gears 2 and 3, and the discharge port 13 is a pump formed between the two gears 2 and 3. Opening from the other side in the axial direction of the two gears 2 and 3 to the discharge region of the chamber.
[0012]
Reference numeral 14 denotes an oil passage formed in the lid member 5, which is connected to the bottom of the suction port 12, bypasses the opening of the housing recess 4, opens a passage port 14 </ b> A at one end surface 5 </ b> A of the lid member 5, and connects the passage port 14 </ b> A to the suction passage. Communicate with 10 road openings 10A. Due to the bypass of the oil passage 14, the minute gap between the inner peripheral surface 4 </ b> A of the housing recess 4 and the outer peripheral surface 2 </ b> A of the internal gear 2 is opposed to the wall portions 1 </ b> C and 1 </ b> D of the pump housing 1. The wall portion 5B that covers is left.
[0013]
The discharge port 13 having a depression formed in the lid member 5 has an oil passage 15 provided continuously at the bottom thereof, and the oil passage 15 bypasses the opening of the housing recess 4 and opens a passage port 15A on one end surface 5A of the lid member 5. 15A coincides with the passage opening 11A of the discharge passage 11 and communicates therewith. By detouring the oil passage 15, the wall portion 5 </ b> C remains on the one end surface 5 </ b> A of the lid member 5 so as to face the wall portion 1 </ b> E of the pump housing 1.
[0014]
Next, the operation of this configuration will be described.
When the gears 2 and 3 are rotated clockwise in FIG. 2 by the rotation of the drive shaft 7, the oil in the suction passage 10 passes through the suction port 8 of the pump housing 1 from the one side surface in the axial direction of the two gears 2 and 3. While being sucked into the suction region of the pump chamber formed between the two gears 2, 3, the two gears 2, via the passage port 10 </ b> A, the passage port 14 </ b> A, the oil passage 14 of the lid member 5, the suction port 12, 3 is sucked into the suction region of the pump chamber formed between the two gears 2 and 3 from the other side surface in the axial direction.
[0015]
The oil sucked into the suction area of the pump chamber is conveyed to the discharge area of the pump chamber as the both gears 2 and 3 rotate, and passes through the discharge port 9 of the pump housing 1 from one axial side surface of the both gears 2 and 3. In addition to being discharged to the discharge passage 11, it is discharged to the discharge passage 11 through the discharge port 13 of the lid member 5, the oil passage 15, the matched road opening 15 </ b> A, and the road opening 11 </ b> A from the other side surface in the axial direction of both gears 2 and 3. Pumping is performed. Then, oil is sucked into the suction area of the pump chamber from both axial sides of the two gears 2 and 3 to improve suction efficiency, and the oil in the discharge area of the pump chamber is discharged from both axial sides of the two gears 2 and 3. Thus, the discharge efficiency can be improved and the pump efficiency can be improved.
[0016]
With this operation, the pump chamber formed between the two gears 2 and 3 from the other side in the axial direction of the two gears 2 and 3 from the suction passage 10 through the passage ports 10A and 14A, the oil passage 14, and the suction port 12 of the lid member 5. When the oil sucked into the suction area flows through the oil passage 14, the minute gap between the inner peripheral surface 4 </ b> A of the housing recess 4 and the outer peripheral surface 2 </ b> A of the internal gear 2 is covered with the wall portion 5 </ b> B included in the lid member 5. Since it does not come into direct contact with the oil flowing through the passage 14, dust in the oil flowing through the oil passage 14 is prevented from entering the minute gap between the inner peripheral surface 4 </ b> A of the housing recess 4 and the outer peripheral surface 2 </ b> A of the internal gear 2. Thus, abnormal wear of the outer peripheral surface 2A of the internal gear 2 and the inner peripheral surface 4A of the housing recess 4 and seizure of the internal gear 2 can be prevented. Further, since the minute gap between the inner peripheral surface 4A of the housing recess 4 and the outer peripheral surface 2A of the internal gear 2 is covered with the wall portion 5B having the lid member 5, the housing recess 4 is formed from both side surfaces of both gears 2 and 3. The high-pressure oil on the discharge ports 9 and 13 side that leaks into the minute gap between the inner peripheral surface 4A and the internal gear 2 outer peripheral surface 2A can be difficult to escape to the oil passage 14, and acts on the outer peripheral surface 2A of the internal gear 2 The pressure can be reduced from decreasing on the suction ports 8 and 12 side in the radial direction, and the internal gear 2 can be applied to the suction port 8 side inner peripheral surface 4A of the housing recess 4 by the pressure acting on the discharge ports 9 and 13 side outer peripheral surface. Pressing can be reduced.
[0017]
In one embodiment of the present invention, the difference in the number of teeth of the two gears 2 and 3 is 2, and a crescent-shaped partition portion for partitioning the suction region and the discharge region of the pump chamber formed between the two gears 2 and 3. Although 1B is provided, the difference in the number of teeth of both gears may be set to 1, and the partitioning portion may not be provided, and the tooth tips of both gears may be opposed to each other through a minute gap to partition the suction region and the discharge region of the pump chamber. Of course.
[0018]
【The invention's effect】
As described above, in the present invention, the minute gap between the inner peripheral surface of the housing recess and the outer peripheral surface of the internal gear is covered by the wall portion of the lid member, and the oil directly flows through the oil passage formed in the lid member from the suction passage. Therefore, it is possible to prevent the dust in the oil flowing through the oil passage from entering the minute gap between the inner circumferential surface of the housing recess and the outer circumferential surface of the internal gear. Abnormal wear on the peripheral surface and seizure of the internal gear can be prevented. In addition, since a minute gap between the inner circumferential surface of the housing recess and the outer peripheral surface of the internal gear is covered with the wall portion of the lid member, the inner surface of the housing recess and the outer peripheral surface of the internal gear from both side surfaces of both gears. The high-pressure oil on the discharge side that leaks into the minute gap between the two can be difficult to escape to the oil passage, and the pressure acting on the outer peripheral surface of the internal gear can be reduced from decreasing on the radial suction port side. It is possible to reduce the pressure applied to the suction port side inner peripheral surface of the housing recess due to the pressure acting on the discharge side outer peripheral surface.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an internal gear pump showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a cross-sectional view taken along line BB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pump housing 1A, 5A One end surface 1C, 1D, 5B Wall part 2 Internal gear 2A Outer peripheral surface 3 External toothed gear 4 Accommodating recessed part 4A Inner peripheral surface 4B Bottom surface 5 Lid member 8, 12 Suction port 10 Suction path 10A Road port 14 Oil Road

Claims (1)

A pump housing in which an outer peripheral surface of the internal gear is slidably supported by the inner peripheral surface and an accommodation recess for accommodating the internal gear and the external gear meshing with the internal gear is formed in one end surface, and one end surface of the pump housing And a lid member installed so as to close the opening of the housing recess by abutting one end surface of the housing, and on the bottom surface of the housing recess, on the suction region of the pump chamber formed between the two gears, on one side in the axial direction of both gears An arc-shaped suction port having a smaller diameter than the inner diameter of the housing recess is formed so as to open more, the suction port communicates with the oil suction passage at the bottom, and the suction path bypasses the housing recess and is more radial than the housing recess The pump housing has a wall opening at one end surface of the pump housing outside the housing, and the pump housing has wall portions between the inner peripheral surface of the housing recess and the passage port of the suction channel, and between the bottom surface of the housing recess and the suction channel. Lid member that contacts one end surface of An arcuate suction port that opens from the other axial side of both gears is formed in the suction area of the pump chamber formed between the two gears on one end surface, and is formed continuously with the bottom of the suction port. An oil passage that bypasses the opening of the suction passage and communicates with the inlet of the suction passage is formed in the lid member, and an inner circumferential surface of the housing recess and an outer peripheral surface of the internal gear are opposed to the wall portion of the pump housing on one end surface of the lid member. An internal gear pump characterized by having a wall portion that covers a minute gap between them.

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