JPS593188A - Gear pump - Google Patents

Abstract

PURPOSE:To make it possible to eliminate the requirement of precision processing where the cover deformation is taken into consideration, by reducing harmful bending force acting on the cover inner face while allowing fluid pressure to act on a mounting board and an outer plate, and supporting said pressure with bolts. CONSTITUTION:The pressurized oil on the high pressure side acts on a piston 8 within a pressure escape hole A, and said piston 8 presses a pump mounting wall 10 and an outer plate 11. Hereby, fluid pressure acts on the mounting wall 10 and the outer plate 11, and these forces are supported by means of bolts 7. Accordingly, the force acting on the inner walls of front and rear covers 4, 5 to bent them is largely reduced. Thus, pump performance is remarkably improved, eliminating the requirement of precision processing where the cover deformation is taken into consideration.

Description

[Detailed description of the invention] The present invention relates to improvements in gear pumps.

In conventional gear pumps, especially those used for high-pressure fluids, the hydraulic pressure in the high-pressure area on the discharge side causes the front and rear bridges to bend away from the side of the gear, creating a gap that can cause oil leaks. Ta. For this reason, it is not necessary to use a strong material for the front and rear covers, and extra care must be taken to ensure that there is no problem even if the front and rear covers are bent to some extent.

An object of the present invention is to eliminate the above-mentioned problems, improve the performance of the pump, and provide a gear pump that does not necessarily require precise machining and can significantly reduce costs.

Hereinafter, one embodiment of the present invention will be explained based on the drawings.

In FIGS. 1 to 8, a pair of gears 8, 8 meshing with each other are connected to a pair of mutually parallel driving shafts 1 and driven shafts 2.
are fixed, and the front and rear covers 4, 5 and the casing 6 are held between them so as to cover both 9111 surfaces and the outer peripheral surface of these gears 8.3.

Then, with the outer cover 11 disposed on the front surface of the IIJ cover 4, it is integrally fixed to the pump mounting wall 10 with the entire MLL bolt 7.

Both of the front and rear covers 4.5 are provided with pressure relief holes A that extend from the inner surface facing the high pressure area, which is the pump discharge side, to the outer circumference. This hole consists of a small diameter hole A located on the gear side and a large diameter hole A2 opened on the outer surface of the front and rear covers. A piston 8 is fitted into the large diameter opening A2 so as to be slidable in the thickness direction of the front and rear covers 4.5, and the gear 81 of the piston 8 has a small diameter and is fitted with a seal on its outer circumferential surface. 9 is inserted and sealed. The surface of the cover where the hole A is opened is crossed by the pump mounting wall 10 and the outer plate 11, and is provided with a fluid seal and a prevention mechanism to prevent the piston 8 from being removed. Reference numerals 4a and 4b are an inlet port and a discharge port, respectively, which are connected to the side surface of the cover 4.5, which is perpendicular to the side surface of the gear 8.

The operating state will be explained above.

The pressure oil on the high pressure region side acts on the piston 8 within the pressure relief hole A, and the piston 8 presses the pump mounting wall 10 and the outer plate 11. As a result, the pressure of the fluid is reduced between the mounting wall 10 and the outer panel 1.
1 and these forces will be supported by the bolt 7. Therefore, the force acting on the inner surfaces of the front and rear covers 4.5 and tending to bend them is greatly reduced.

In addition, rjrJ hole A and piston 8 are nIJ rear cover 4.
It may be provided only at any one of 10,000° and 10,000°.

Since the present invention is as described above, the bending force acting on the inner surfaces of the front and rear covers is reduced, which dramatically improves the performance of the pump.
There is no need for detailed machining, making it possible to reduce costs by 54%. Moreover, since the piston is sealed and inserted into the pressure relief hole, even if a gap occurs between the pump mounting wall or the outer plate and the force/<-, the sealing condition of the piston will not change and it will always work. A good sealing effect is obtained, and the strength of the cover is hardly reduced even with the pressure relief holes.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, FIG. 2 is a right side view, and FIG. 8 is a sectional view taken along the line n+-n+ of FIG. 1... Drive shaft, 2... Driven shaft, 8... Confederate army, 4...
...Front cover, 5...Rear cover, 6...Casing, 7...Packing, 8...Piston/, A...Pressure relief hole, 80...Small diameter hole, A,... ...Large diameter hole agent Patent attorney Shinpei Inukai No. 3 Figure 2 3

Claims (1)

[Claims] A pair of gears meshing with each other are fixed to a pair of mutually parallel driving shafts and driven shafts, and a front and rear cover covers both sides and outer circumferential surfaces of these gears, and one side penetrates from the inner surface facing the high pressure area to the outer surface. A pressure relief hole is provided, a piston is sealed in the hole and slidably inserted in the thickness direction of the front ID cover, and the surface of the cover where the relief hole is opened is covered with a pump mounting wall or an outer plate. A gear pump characterized by: