JPH0315830Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a gear pump in which a driving gear and a driven shaft gear are disposed so as to be displaced toward a fluid discharge portion side.

A gear pump has a driving gear and a driven shaft gear that mesh with each other in a casing, and transmits power to the driving gear and rotates both gears to transport fluid under high pressure, and requires a high degree of watertightness. Ru. Fig. 4 shows a conventional gear pump of this type, in which a driving gear d and a driven shaft gear e are arranged in gear storage chambers b and c of a casing a, and both gears d and e are rotated. The fluid is sucked into the casing a from the liquid suction part f and discharged from the discharge port g, but sliding friction occurs between the gears d and e and the inner peripheral surfaces of the storage chambers b and c. In order to prevent this from occurring, the inner diameters r ₁ and r ₁ of the storage chambers b and c are made slightly larger than the outer diameters r' and r' of the gears d and e, and a small distance t (usually about 1 to 5 micron), but
In order to improve the sealing effect and ensure high pressure in the area close to the discharge port g, the inner diameter _r2 of the storage chambers b and c is partially reduced.
The inner circumferential surface of the gears d and the outer circumferential surface of the gears e are brought closer to each other, and the distance t between them is gradually reduced toward the discharge port g. However, if the internal diameters of the storage chambers b and c are locally rapidly reduced in the _r2 region L, the fluid pressure P acting on the gears d and e will rapidly increase in the _r2 region L, and due to this pressure, Both gears d and e are strongly pushed toward the low pressure side (liquid suction part f side). For this reason, strong sliding friction occurs between the inner circumferential surface of the bearing hole h of the driven shaft gear e and the outer circumferential surface of the driven shaft i, which is loosely attached to the bearing hole h.
The problem was that it gradually wore out, causing looseness, lowering the hydraulic pressure and reducing the pumping force.

Therefore, the present invention has been made for the purpose of providing a gear pump that eliminates the drawbacks of the conventional pumps described above, and in which the driving gear and the driven gear are disposed closer to the discharge portion than the center of the gear storage chamber of the casing. As a result, the distance between the outer peripheral surfaces of both gears 8 and 9 and the inner peripheral surfaces of each gear storage chamber 6 and 7 is gradually reduced from the liquid suction section 18 side toward the discharge section 19 side. By doing this, the outer circumferential surface of the gear gradually approaches the circumferential surface of the gear storage chamber toward the discharge part of the casing, preventing the fluid pressure on the discharge part side from increasing rapidly, and thereby preventing the bearing of the driven gear. The inner circumferential surface of the hole is strongly pressed against the outer circumferential surface of the driven shaft by fluid pressure and rotates in sliding contact, thereby preventing unnecessary wear. Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 to 3, 1 is a casing, and the casing 1 includes a collar 2 and a collar 2.
It consists of a gear receiving part 3 connected to the back of the gear. The gear storage section 3 is formed by connecting two substantially cylindrical bodies 4 and 5, and gear storage chambers 6 and 7 are provided inside thereof in a connected manner, respectively. Reference numeral 8 indicates a drive gear, and reference numeral 9 indicates a driven gear. The drive gear 8 is attached to a drive shaft 10, and the driven gear 9 is rotatably attached to a driven shaft 12 through its bearing hole 11. They are arranged in the storage chambers 6 and 7 and mesh with each other. 13 is the collar part 2
The driven shaft 12 is a lid plate that is fitted into the cylindrical body 5 and the lid plate 13 to seal the storage chambers 6 and 7.
bearing recesses 1 recessed in the inner wall surface of each
4 and 15, one end of the drive shaft 10 is rotatably supported in a bearing recess 16 formed in the inner wall surface of the cylindrical body 4, and the other end is formed in the cover plate 13. It passes through the small hole 17 and is driven and rotated by a motor (not shown). Reference numeral 18 denotes a liquid suction pipe as a liquid suction section connected to the lower center of the casing 1; 19 denotes a discharge port as a discharge section opened at the upper center of the back surface of the casing 1;
A discharge pipe 20 is connected to the discharge pipe 20 .

The shape of the inner circumferential surface of the storage chambers 6, 7 is a perfect circle, and the inner diameters R, R are the outer diameters R' of the gears 8, 9,
slightly larger than R′. Furthermore, the bearing recesses 14, 15, 16 and the small holes 17 are formed to be slightly displaced from the centers O and O of the storage chambers 6 and 7 toward the high pressure side, that is, toward the discharge port 19. The centers O' and O' of 8 and 9 are slightly displaced from the centers O and O to the high pressure side. Therefore, the distance between the outer circumferential surface of gears 8 and 9 and the inner circumferential surface of storage chambers 6 and 7 is maximum (tmax) at the lower side near suction pipe 18.
It gradually becomes smaller as it approaches the discharge port 19, and reaches its minimum (tmin) at the point closest to the discharge port 19, where the outer circumferential surfaces of the gears 8, 9 are almost in sliding contact with the inner circumferential surfaces of the storage chambers 6, 7.

When gears 8 and 9 are rotated in the above configuration,
The fluid is sucked into the casing 1 from the liquid suction part 18 and discharged from the discharge port 19 to the outside of the casing 1, but as described above, the fluid is sucked into the outer circumference of both gears 8 and 9 and the inner circumference of the gear storage chambers 6 and 7. Since the distance between the surfaces gradually decreases from the suction pipe 18 side to the discharge pipe 19 side, the fluid pressure P gradually increases from the lower side (tmax point) toward the discharge port 19. ，
9 is not strongly pushed toward the low pressure side by receiving an extremely larger fluid pressure near the discharge port 19 than in other parts. Therefore, the sliding friction between the inner circumferential surface of the bearing hole 11 of the gear 9 and the outer circumferential surface of the driven shaft 12 is small, so that sliding abrasion between the two is prevented, and a sufficient sealing effect of the high pressure section can be obtained.

As explained above, the gear pump according to the present invention has two gear storage chambers 6 and 7 each having a circular inner peripheral surface.
are connected and provided, and a liquid suction part 18 is provided on one side of the center,
Further, a drive gear 8 is provided in each of the gear storage chambers 6 and 7 of the casing 1, which is provided with a discharge part 19 on the other side of the center.
By arranging the driven gear 9 which is loosely attached to the driven shaft 12 and displaced toward the discharge portion 19 side from the center O of each of the storage chambers 6 and 7, the outer peripheral surfaces of both gears 8 and 9 and The distance between the inner peripheral surfaces of each gear storage chamber 6, 7 is
Since the fluid pressure is gradually reduced from the liquid suction section 18 side to the discharge section 19 side, the increase in fluid pressure toward the discharge section 19 side is gradual, and therefore the gears 8 and 9 are on the low pressure side. This can prevent the bearing hole 11 of the driven shaft 9 and the driven shaft 12 from being worn out due to being pushed strongly.

[Brief explanation of drawings]

The figure shows an embodiment of the present invention.
The figure is an exploded perspective view of the gear pump, the second figure is a cross-sectional view,
FIG. 3 is a plan view, and FIG. 4 is a plan view of a conventional one. 1... Casing, 6, 7... Gear storage chamber, 8
... Drive gear, 9 ... Driven gear, 12 ... Driven shaft, 18 ... Liquid suction pipe as a liquid suction section, 19 ... Discharge port as a discharge section.

Claims (1)

[Scope of utility model registration request] Each of the above-mentioned casing 1 has two gear storage chambers 6 and 7 having a circular inner circumferential surface connected to each other, a liquid suction part 18 on one side of the center, and a discharge part 19 on the other side of the center. A drive gear 8 is located in the gear storage chambers 6 and 7.
By arranging the driven gear 9 whose bearing hole 11 is loosely attached to the driven shaft 12 to be displaced from the center O of each of the storage chambers 6 and 7 toward the discharge portion 19,
A gear pump characterized in that the distance between the outer peripheral surfaces of both gears 8 and 9 and the inner peripheral surfaces of each gear storage chamber 6 and 7 is gradually reduced from the liquid suction section 18 side to the discharge section 19 side.