JPS5943516Y2 - gear pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circumscribed gear pump that is used as a hydraulic pressure source for driving a hydraulically operated device.

This type of conventional gear pump is shown in Figures 1 and 2.
A cylindrical housing 5.6 for accommodating a pair of gears 1.3 that mesh with each other is cut into the end face of the main body 10, and one end of the shafts 2 and 4 supporting the gears 1.3 is attached to the main body 10. The other end is rotatably supported in the shaft hole of the end plate 9 that closes the open end of the housing 5.6, and one of the gears 1.3 is When the housings are driven and both are rotated in the direction of the arrow X, the working fluid sucked in from the suction port 11 is sent along the curved surfaces of the housings 5 and 6, and is forced to the outside from the discharge port 12. In the above-mentioned conventional gear pump, the discharge port extends from the suction port 11, to both end faces of each gear 1.3, and to the side wall face 7 of the housing.
8, the meshing portion of each gear 1.3, and the sliding portion of each gear 1.3 and the inner peripheral surface of the cylindrical housing 596.

As for the third sliding contact portions mentioned above, the portions A and B where each housing 5.6 and the wall surface 13 connect, which are close to the suction port 11, play an important role.

This is because each gear 1.3 is pressed against the wall surface 13 by the hydraulic pressure F of the discharge port 12, and is also brought into closest contact with the parts A and B.

Therefore, as shown in Fig. 3.4, the inner circumferential surface of the cylindrical housing 5.6 is further extended toward the suction port 11, so that the sliding parts A and B with each gear 1 and 3 are mutually The spacing is 1 for each gear.
, 3, the sealing effect can be further improved.

However, with such a configuration, especially in a hydraulic pump of the type in which the side wall surface that makes sliding contact with one end surface of each gear 1, 3 is integrally formed with the main body 10, from a processing standpoint, as shown in FIG. Side wall surface 8 of housing 5 and side wall direction 81 of housing 6
It is inevitable that a step δ will occur between the two.

If there is such a step, the side wall surface 8. There is a problem that a gap is created between the end face of the gear 3 and the end face of the gear 3, and the pressure of the discharge port 12 leaks from the gap to the suction port 11, resulting in a significant decrease in volumetric efficiency.

[Purpose of invention]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a gear pump that can improve the sealing effect between the nozzle and the side wall surface of the gear, and improve the volumetric efficiency.

[Structure of the idea]

In order to achieve the above object, the present invention has developed a cylindrical housing housing a pair of gears, which intersects a straight line connecting the axes of the pair of gears at a right angle at the meshing center of both gears. By connecting each housing with an arc-shaped wall surface centered at a point on the suction port side on a straight line, there is no step difference in the machining of the side wall of each housing, and each nozzle and each gear on the suction port side are connected to each other. The space between the seal parts can be reduced.

In other words, the structure of the present invention is such that the inner circumferential surfaces of the cylindrical housing housing the driving gear and the cylindrical housing housing the driven gear lie on a straight line that is orthogonal to the center of the gear meshing center with the straight line connecting the centers of both housings. The parts A and H are connected to each other by an arc-shaped wall surface centered at a point on the suction port side, so that both gears crossing the suction port slide against the wall surface on the suction port side, sealing the suction port from the discharge port side. The distance between the two gears is made shorter than the distance between the axes of both gears.

The structure of the present invention will be explained based on the illustrated embodiment. As shown in FIG. 3
0 is set.

The right end of the shaft 2 of the gear 1 is supported in the shaft hole 27 through a cylindrical bushing 26, and the right end of the shaft 4 of the gear 3 is supported in the shaft hole 30 through a cylindrical bush 38. the shaft 4 extends outwardly through the body 10;
It is designed to be connected to the prime mover.

The end of the shaft 4 is sealed by a sealing member 29,
The shaft hole 27 and the cavity in which the seal member 29 is mounted are connected via a passage 28.

On the other hand, a step is provided on the left end surface of the main body 1o along the peripheral edge of the housing 5, and an annular side plate 21 is abutted against this step. The end plates 9 are abutted through rings 35, 36 and 4o and are connected to the main body 10 with four bolts 37.

The end plate 9 is also provided with shaft holes 22 and 39, in which the left end of the shaft 2 is supported through a bush 23, and the left end of the shaft 4 is supported through a bush 34, respectively.

Each shaft hole 22, 39 is connected to each other by a hollow part 41,
It is also connected to the passage 28 by a passage 42 passing through the shaft 2 .

According to the present invention, as shown in FIG.
has cylindrical parts centered on the center Cl-C2, and these cylindrical parts are connected to each other by arcuate wall surfaces 13,14.

That is, with respect to the line connecting Cl-C2, the arc-shaped wall surface 13.1 is in contact with the housings 5 and 6, with the 0 point on the suction port 11 side on the line 32 passing through the meshing center of the gear 1.3 as the center.
4 is composed.

Therefore, the housing 5 has a semi-cylindrical shape from part A clockwise to part C, and the housing 6 has a semi-cylindrical shape from part B to part C in a counterclockwise direction.

By appropriately selecting the position of the 0 point, the interval between portions A and B can be made sufficiently smaller than the interval between the centers Ct*C and z.

And part A. A suction port 11 is provided on the side of the convex wall surface 13 that connects portions B, and a discharge port 12 is provided on the side of the concave wall surface 14 that connects portions C and D.

Since the present invention is constructed as described above, the working fluid in the suction port 11 is caused to flow into the fluid that enters between the teeth of each gear as the gear h3 rotates in the direction of the arrow X, as in the case of FIG. are parts A and B
The housing 5 is sealed from the suction port 11 at each location.
．． It is sent to the discharge port 12 through the inner circumferential surface of the discharge port 6 .

The pressure of the discharge port 12 acts on a projection plane connecting the centers C1eC2 of each gear 1, 3, and pushes each gear 1.3 to the left, that is, toward the suction port 11 side.

Due to this pressing force, the gear 1.3 is most closely engaged in the portions a, b of the housing 5.6, and the degree of closeness becomes smaller as the distance from the portion atb in the circumferential direction increases.

In the present invention, the portions A and B where the housing 5.6 is sealed from the suction port 11 are located inside the maximum pressure acting portion atb, so that a sufficiently high sealing effect can be obtained.

For example, the housing 5.6 is first machined by processing the nozzle 5 while moving a rotary blade capable of simultaneously cutting the circumferential surface and the end surface in the axial direction from the end surface of the main body 10 along the center C1.
The axial feed of the cutter is stopped at the side wall surface 8, and the cutter is then moved to 0.
The side wall surfaces 13, 14 are machined by pivoting around a point or by rotating the main body 10, and the inner circumferential surface of the nosing 6 is finished when the center of the cutter comes to the center C2.

Finally, it is only necessary to pull out the cutter from the main body 10 in the axial direction, and since the side wall surface 8 of the housing 5.6 is finished completely flat, it is possible to eliminate leakage from the side wall surface 8 that seals the end surface of each gear 1.3. can.

[Effect of idea]

In short, the present invention is a gear pump in which a pair of cylindrical housings housing a pair of gears are connected to each other by a convex wall surface and a concave wall surface having a common arc shape. With this configuration, the side wall surface of the nozzle can be machined flat without any steps by rotating the rotary cutter that finishes the circumferential surface and the end surface at the same time about the aforementioned center. Rather, the distance between seal parts A and B, where a pair of gears slide against the cylindrical inner surface of the housing on the suction port side, is determined by the maximum hydraulic pressure that presses each gear against the inner surface of the housing. Point a
sb can be set smaller than the interval sb, and therefore the sealing effect between the discharge port and the suction port on the circumferential surface and side wall surface of the housing can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a conventional gear pump, Fig. 2 is a front sectional view of the same, Fig. 3 is a side sectional view of another conventional gear pump, Fig. 4 is a front sectional view of the same, and Fig. 5 is a sectional view of the same. FIG. 6 is a front sectional view of the gear pump according to the present invention, and FIG. 6 is a left side view of the housing body of the gear pump. 1.3: Gear, 5, 6: No. 7, 8: Side wall surface, 9: End plate, 10: Main body, 1: Suction port, 12: Discharge port,
13; 14: Wall surface.

Claims (1)

[Scope of utility model registration request] The inner peripheral surfaces of the cylindrical housing housing the driving gear and the cylindrical housing housing the driven gear are on the suction port side on a straight line that is perpendicular to the straight line connecting the centers of both housings at the center of gear meshing. The mutual spacing between portions A and B is such that they are connected to each other by an arc-shaped wall surface centered at one point, and thereby both gears crossing the suction port slide against the suction port side wall surface to seal the suction port from the discharge port side. A gear pump characterized in that the spacing between both gears is narrower than that between the two gears.