JPH1144293A - Internal gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain an increase in leakage of discharge fluid in discharge passage recesses of a case and a cover in order to improve a pump efficiency by forming the recesses radially outer than a receiving recess, and forming a communication means communicating a discharge area with a discharge passage into a tunneled through hole. SOLUTION: When an internal gear 2 and an external gear 3 are rotated with the rotation of a drive shaft 6, such a pumping action is performed that fluid is taken in from an intake passage 26 and discharged to a discharge passage 25. Part of the fluid discharged is discharged to the passage 25 via tunneled through holes 15, 24 from each of discharge port recesses 7, 20. In the vicinity of the discharge part of the gear 2, the outer peripheral surface of the gear 2 is not exposed to discharge passage recesses 12, 22. Accordingly, such a case is prevented that the discharge pressure acts on the outer periphery of the gear 2 to push the gear 2 to the diametrical direction. Namely, a seal gap at a tooth top of each of gears 2, 3 becomes large to solve a problem of an increase in leakage of discharge fluid to the intake side, resulting in the provision of a high efficiency pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field 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 lubrication of an engine in an automobile or an automatic transmission.

[0002]

2. Description of the Related Art Such an internal gear pump is disclosed in
FIG. 5 shows the vicinity of a portion where the ink is ejected separately. In other words, the internal gear A and the external gear B are housed in the housing recess D opened at one end of the case C, and the lid is installed with one end abutting on one end so as to close the opening of the housing D. A member E is provided. Housing recess D of case C
Discharge port concave portions F and G are formed in the end wall and one end surface portion of the lid member E opposed thereto, from which the discharge port concave portions F and G extend more radially outward than the housing concave portion D.
Discharge passage recesses H, I for forming a part of the discharge passage
Each of the discharge passage recesses H and I is closed together with the housing recess D by placing the cover member E in contact with the case C.

[0003]

In this arrangement, the discharge passage recesses H and I for the discharge passage extend radially outward from the respective discharge port recesses F and G. In the range of H and I, the outer peripheral surface of the internal gear A is directly exposed to the concave portions H and I for the discharge passage. Therefore, the discharge fluid in the discharge passage concave portions H and I directly acts on the outer peripheral surface of the internal gear A, and presses the internal gear A in the radial direction by the pressure. Since the inner diameter of the housing recess D is slightly larger than the outer diameter of the internal gear A, the internal gear A is slightly moved by this pressing, and the outer circumference of the internal gear A and the inner circumference D of the housing recess D at the discharge passage recesses H and I. In the portion where the suction area and the discharge area are separated by the sealing engagement of the tooth tip surface inside the internal gear A, the gap between the tooth tips is increased by the movement of the internal gear A. Is increased, leakage from the discharge area to the suction area through these gaps increases, the volumetric efficiency is reduced, and the internal gear A is pressed against the inner peripheral surface of the housing recess D by the pressing, resulting in a torque loss. In addition, there is a problem that the efficiency of the internal gear pump is reduced. The present invention is intended to solve such a problem.

[0004]

Therefore, in the present invention,
A case in which an outer peripheral surface of the internal gear is slidably supported by the inner peripheral surface and a receiving recess for receiving the internal gear and the external gear meshing with the internal gear is formed in one end surface. A lid member is provided to abut the end face to close the opening of the accommodation recess, and a portion of the end wall of the accommodation recess and a portion of the abutment-side end face of the lid member opposed to the accommodation recess end wall has a discharge port recess in the ejection area. Is formed on one end face of the case and the end face on the contact side of the lid member, the recess for the discharge passage which is closed by the contact installation of the lid member to the case and forms a part of the discharge passage is opened. In the internal gear pump, both the recess for the discharge passage of the case and the lid member are formed outside in the radial direction than the recess for the housing, and the communicating means for allowing the discharge area and the discharge passage to pass through the discharge port recess and the tunnel for allowing the discharge passage recess to pass therethrough. Through hole Hole was to be provided on at least one of the case and the lid member.

[0005] In this case, even if the tunnel-shaped through-hole is provided in both the case and the cover member, only one of them (for example, the case) is provided, and the other (for example, the cover member) is provided with a through-hole. It may not be necessary. When the through-hole is provided in both the case and the cover member, the discharge fluid from the discharge area is guided from the respective discharge port recesses to the discharge passage through the through-hole. (For example, the case), the discharge fluid from the discharge area
The discharge port concave portion on the side where the through hole is provided is guided to the discharge passage via the through hole, and is not guided to the discharge passage from the other discharge port concave portion (for example, the lid member).

According to such a configuration, the discharge passage recess is located radially outward of the housing recess, and is formed in a tunnel-shaped through hole through which the discharge port recess and the discharge passage recess pass. Since the fluid is guided to the discharge passage, the outer peripheral surface of the internal gear does not expose to the discharge passage concave portion, and the discharge fluid in the discharge passage concave portion directly presses the outer peripheral surface of the internal gear. It is possible to prevent a situation in which the discharge fluid in the discharge passage recess directly acts on the outer peripheral surface of the internal gear, which causes the internal gear to move, thereby causing an increase in leakage and an increase in torque loss.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to a pump for lubricating an automobile engine will be described below with reference to the drawings. Reference numeral 1 denotes a case, in which a housing recess 4 for housing an internal gear 2 and an external gear 3 meshing with the internal gear 2 is formed in one end face 1A thereof. The inner peripheral surface of the housing recess 4 slidably supports the outer peripheral surface of the internal gear 3. Reference numeral 5 denotes a lid member which is provided so that one end face 5A thereof is in contact with one end face 1A of the case 1 to close the opening of the accommodation recess 4. 6
Is a drive shaft, which is fitted to the external gear 3 so as to rotate the external gear 3.

The end wall 4A of the housing recess 4 is formed with a discharge port recess 7 corresponding to the discharge area and a suction port recess 8 corresponding to the suction area. In the suction port recess 8,
A recess 9 for the suction passage is provided so as to extend radially outward in such a manner that the circumferential wall of the housing recess 4 is cut out and is open to the one end face 1A.
Leads to 1.

Reference numeral 12 denotes a discharge passage recess formed in the one end face 1A and formed radially outside the housing recess 4 and communicates with the discharge opening 14 through a through hole 13.
The discharge passage recess 12 and the discharge port recess 7 are
It is communicated by a tunnel-shaped through hole 15 which does not cut off the peripheral wall of the housing recess 4. Since the recesses 7 and 12 pass through the through holes 15 in this way, a cover portion X that covers the peripheral portion of the internal gear 2 is formed on the outer peripheral side of the discharge port recess 7 on the end wall 4A of the housing recess 4. (See FIG. 1). Reference numeral 16 denotes a relief valve installation cylinder, which houses a relief valve for releasing the fluid discharged from the concave portion 12 from the opening 17 when the pressure of the fluid exceeds a set pressure and rises. Reference numeral 18 denotes an escape recess through the opening 17 and the recess 9 for the suction passage.

On the one end face 5A of the lid member 5, a suction port recess 19 corresponding to the suction port recess 8 and a discharge port recess 7 are provided at locations facing the end wall 4A of the housing recess 4.
A discharge port recess 20 is formed to correspond to the suction port recess 19.
The concave portion 21 for the suction passage, which matches the shape of the concave portion for the discharge passage 12
The recess 22 for the discharge passage and the recess 21 for the suction passage
Relief recess 23 which matches said relief recess 18 leading to
Are formed in the one end face 5A, respectively. Reference numeral 24 denotes a tunnel-shaped through-hole which does not open to the one end face 5A and allows the discharge port recess 20 and the discharge passage recess 22 to pass through. In this way, the recesses 20 are formed by the through holes 24,
As a result, a cover Y covering the peripheral portion of the internal gear 2 is formed on the outer periphery of the discharge port recess 20 on one end face 5A (see FIG. 1).

When the cover member 5 is installed in the case 1, the discharge passage recesses 12 and 22 are closed to coincide with each other, and a series of discharge passages 25 communicated to the discharge opening 14 through the recesses 12 and 22 and the through hole 13. Are formed, and the suction passage recesses 9 and 2 are formed.
1 also coincide with each other and are closed.
0 forms a series of suction passages 26 leading to the suction opening 11, the escape recesses 18 and 23 also coincide with each other and close, and a series of escape passages for joining the escape fluid from the opening 17 to the suction passage 26 are formed. It is formed.

The operation of this embodiment will be described. When the two gears 2 and 3 are rotated by the rotation of the drive shaft 6, a pump operation for sucking fluid from the suction passage 26 and discharging the fluid to the discharge passage 25 is performed. The liquid is discharged from the discharge port recesses 7 and 20 to the discharge passage 25 through the through holes 15 and 24, respectively. In the vicinity of the discharge location of the internal gear 2, the discharge passage recesses 12 and 22 are provided in the housing recess 4.
And the outer peripheral surface of the internal gear 2 is not exposed to the discharge passage recesses 12 and 22. For this reason, the discharge fluid does not directly act on the outer peripheral surface of the internal gear 2, and a situation in which the discharge pressure directly acts on the outer periphery of the internal gear and the internal gear is pushed in the radial direction is prevented.

Further, a cover portion X is formed on the outer peripheral side of the discharge port concave portion 7 on the end wall 4A of the housing concave portion 4 so as to cover the peripheral portion of the internal gear 2, and the discharge port concave portion 20 is formed on one end surface 5A of the lid member 5. Are formed on the outer periphery of the internal gear 2 so that the fluid to be discharged flows into the outer periphery of the internal gear 2 and presses the gear 2 in the radial direction. The situation can be suppressed. That is, as compared with the case where the peripheral portion of the internal gear is directly exposed to the discharge fluid in the vicinity of the discharge location, the gap between the cover portions X and Y and each end face of the internal gear 2 is larger than the discharge port recess 7. , 20 exerts a large throttle action when flowing into the outer periphery of the internal gear 2, and as a result, the discharge fluid is suppressed from flowing into the outer periphery of the internal gear 2, and the gear 2 is pressed in the radial direction. The situation can be suppressed.

As described above, in this embodiment, since the pressing action of the discharge fluid in the radial direction of the internal gear 2 can be suppressed, the internal gear 2 moves in the radial direction by the press action of the discharge fluid. The gap between the outer circumference and the inner circumference of the housing recess 4 increases on the discharge passage 25 side, and the leakage of the discharge fluid to the suction side increases through the increased clearance. In the gear 2, the gap between the teeth of the gears 2 and 3, which separate the suction area and the discharge area from each other, is increased, so that the occurrence of a situation where the leakage of the discharge fluid to the suction side through the gap is increased. Thus, a decrease in volumetric efficiency can be prevented. Further, since the pressing action of the internal gear 2 in the radial direction is suppressed, the internal gear 2 is pressed in the radial direction, and as a result, the internal gear 2 comes into strong contact with the inner periphery of the housing recess 4 and the torque loss increases. Generation can also be suppressed, and a highly efficient pump can be obtained.

In this embodiment, the case 1 and the cover member 5 are provided with a through hole 15 through the discharge port recess 7 and the discharge passage recess 12 and a through hole 24 through the discharge port recess 20 and the discharge passage recess 22. Although each is provided, one of the through holes 15 and 24 may be omitted. In this case, the discharge port concave portion (for example, the concave portion 20 when the through hole 24 is omitted) does not discharge the fluid to the discharge passage 25, but the discharge pressure in the discharge port concave portion causes the discharge port not to omit the through hole. The two gears 2 and 3 are pressed in the axial direction against the pressing action of both gears 2 and 3 in the axial direction by the discharge pressure in the concave portion, and the axial acting force on both gears 2 and 3 is balanced. It is useful for

In the embodiment shown, the two gears 2,
3, the difference between the number of teeth is 1. However, when the number of teeth is set to 2 or more, in order to separate the suction area and the discharge area in the internal gear, the tooth tips of both gears are formed at the transition from the suction area to the discharge area. An internal gear pump provided with a crescent-shaped seal piece that slides and engages can also be used.

[0017]

As described above, according to the present invention, the outer peripheral surface of the internal gear does not expose to the discharge passage concave portion, and the discharge fluid in the discharge passage concave portion directly acts on the outer peripheral surface of the internal gear. This suppresses a situation where the internal gear is pressed and moved to cause an increase in leakage and an increase in torque loss, and a highly efficient internal gear pump can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along line BB of FIG. 2, showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

FIG. 3 is a right side view of the case 1.

FIG. 4 is a left side view of the lid member.

FIG. 5 is a sectional view showing a main part of a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 case 2 internal gear 3 external gear 4 accommodation recess 5 lid member 7, 20 discharge port recess 12, 22 discharge passage recess 15, 24 through hole 25 discharge passage

Claims (1)

[Claims] A case in which an outer peripheral surface of the internal gear is slidably supported by the inner peripheral surface, and a housing recess for housing the internal gear and the external gear engaged with the internal gear is formed in one end surface; A lid member is provided for abutting one end surface on one end surface to close the opening of the accommodation recess, and the end wall of the accommodation recess and the portion facing the accommodation recess end wall of the one end surface of the lid member have a discharge area. A discharge port recess is formed, and a discharge passage recess is formed on one end surface of the case and the one end surface of the lid member, the discharge passage concave portion being closed by the contact of the lid member with the case to form a part of the discharge passage. In the internal gear pump, the case and the recess for the discharge passage of the lid member are both formed outside in the radial direction from the housing recess, and the communication means for passing the discharge area and the discharge passage is made to pass through the discharge port recess and the discharge passage recess. It is a tunnel-shaped hole An internal gear pump in which the through hole is provided in at least one of the case and the cover member.