JPS5924276B2 - gear pump or motor - Google Patents

Description

[Detailed Description of the Invention] This invention divides the outer surface of a bush or side plate provided on the side of a gear into a high pressure area and a low pressure area, and maintains the pressure balance by introducing the required pressure oil into each area. It relates to a gear pump or motor (hereinafter referred to as a gear pump, etc.).

In high-pressure, high-performance gear pumps, etc., the gap formed between the body and the outer diameter of the gear must be accurate.

However, even if it is attempted to obtain accurate dimensions by machining, there are problems such as it is almost impossible to obtain, or it is very time-consuming.

Therefore, at the manufacturing stage of gear pumps, etc., the dimensions are such that the tips of the teeth are in contact with the inner diameter of the body, and during break-in, the inner diameter of the body is scraped off by the tips of the teeth, and the dimensions of the gap are accurately determined. I am trying to define it.

However, such rough driving naturally generates chips when the body is scraped, and how to dispose of these chips becomes a problem.

In particular, in conventionally known gear pumps, etc., the high pressure area is communicated with the discharge side of the gear pump, etc., and the high pressure oil on the discharge side is guided to the high pressure area, but the pressure inside this high pressure area is The structure was not designed to further circulate oil.

For this reason, once chips flow into the high-pressure area, the chips do not flow out easily, and may unexpectedly flow into the circuit and damage other equipment such as valves.

In addition, especially when the pump or the like is operated at high pressure and low rotation speed, a large amount of pressure oil leaks from the gear side surface and tooth tip clearance, generating high heat, and this heat increases the pump temperature.

Along with this, the oil temperature in the high pressure area also rises, which poses the problem of damaging seals, etc., which have a low melting point, for example.

In other words, there were problems with the rubber seal hardening and the backup melting.

The purpose of this invention is to circulate the pressure oil in the high pressure area using the oil trapped in the gear, to prevent the accumulation of chips generated during the break-in operation, and to allow this circulating oil to flow along the seal. It is an object of the present invention to provide a gear pump or motor in which the seal is cooled so that it is not easily damaged.

This will be explained below with reference to the illustrated embodiment.

Gears 2 and 3 are housed inside the case body 1, and bushings 8 to 11 that hold the gear shafts 4 and 7 are arranged on both sides of the gears 2 and 3, and covers 12 and 11 are arranged on both sides of the case body 10. It is blocked by 13.

Note that the bushes 8 and 10, and 9 and 11 form sets, and the configuration of each set is substantially the same, so the bushes 9 and 11 will be explained below.

A recessed surface 14 is formed on the outside of the case body 1 around the hole into which the bushing 9.degree. 11 is fitted, and an outer seal 15 is fitted around the recessed surface 14.

The outer side of the bushing 9.degree. 11 housed in the case body 1 is made to protrude outward from the recessed surface 14 and is at the same level as the cover joint surface of the case body 1.

Concave grooves 17, 18 are formed on the outer surface of the bushings 9, 110, which are on the same level as the cover joint surface, at the half circumference of the side path of the discharge hole 16 of the pump, and the inside of the concave grooves 17, 18 and the inside of the concave grooves 17, 18 of the pump are An inner seal 20 is fitted to the outer periphery of the bushes 9 and 11 on the suction hole 19 side.

The grooves 17 and 1B are formed wider than the inner seal 20, so when the inner seal 20 is fitted, a space is created in the grooves 17 and 18, but the space is filled with the passage 21. It is said that

By fitting the outer seal 15 and the inner seal 20 in this manner, a first high pressure area FH is formed between the seals 15 and 20, and a low pressure area L is formed inside the seal 20.

However, the above-mentioned low-pressure area completely surrounds the portion corresponding to the rotational position of the gear where the pressure within the tooth space changes drastically depending on the number of rotations of the gear.

A second high pressure area SH is formed within the low pressure area L at a position corresponding to the rotational position of the gear where the pressure in the tooth space changes drastically depending on the rotation speed of the gear. This second high pressure area SH communicates with the tooth groove through communication holes 22 and 23.

The bushing 9 has a first high pressure area FH1, a second high pressure area SH and a low pressure area L defined on the outside as described above,
The inner surface of 110 has the configuration shown in FIG.

That is, low pressure introduction holes 24 and 25 are formed on the suction hole 19 side of the case body 1.

The low pressure oil introduced from the low pressure introduction holes 24 and 25 reaches the low pressure area L via the periphery of the gear shaft 5.7.
Further, the low pressure is returned to the suction hole 19 from the low pressure outlet hole 26 formed in the low pressure area L.

Also, on the discharge hole 16 side, both bushings are 9° 110°.
High pressure introduction hole 2 formed by a concave part formed on the mating surface
7, and a recess 29 is formed around the opening of one end of the high pressure introduction hole 27 on the inner surface of the bushing 9.
It is opened inward.

The first high pressure area FH communicates with the discharge hole 16 through a high pressure outlet hole 28 formed by a notch formed in the case body 1 and the bushes 9 and 11 together.

However, when the gears 2 and 3 are now rotated in the direction of the arrow in FIGS. 4 and 5, the oil sucked in from the suction hole 19 passes around the gears 2 and 3 and is discharged from the discharge hole 16.

At this time, the low-pressure oil introduced from the low-pressure introduction hole 24 circulates as described above, and the high-pressure oil trapped in the tooth groove on the discharge side is compressed during the course of 2.30 rotations of the gear, and the high-pressure oil is Forcibly sent into 27.

The high-pressure oil sent into the high-pressure introduction hole is introduced into the first high-pressure area FH via the passage 21 and is pushed out from the high-pressure outlet hole 28 to the discharge hole 16.

That is, the high pressure oil on the discharge hole 16 side flows through the high pressure introduction hole 27, the passage 21, the first high pressure area FH and the high pressure outlet hole 28, and balances the bushings 9, 110 loading force.

In addition, the gears 2 and 3 in the illustrated embodiment have the tooth surfaces opposite to the tooth surfaces on which rotational force acts upon mutual contact among both gears undercut to a position larger than the pitch circle diameter. Although it is a smaller version of the pitch module,
Of course, in carrying out this invention, a normal involute gear may be used.

Further, in this invention, it is clear that thin side plates may be provided on both sides of the gear instead of the bushings.

As is clear from the above explanation, according to the gear pump etc. of the present invention, the high pressure oil introduced into the high pressure area is constantly circulated, so chips generated during the break-in operation of the pump etc. accumulate. I won't.

Therefore, problems such as malfunctions of other equipment such as valves due to cuttings from the cutting are eliminated.

In addition, the high-pressure oil circulates in the high-pressure area via the seals that partition the high-pressure area.
It functions to cool this seal, etc.

Therefore, even if the temperature of the pump etc. rises,
The seal will no longer harden or the backup will melt.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view, and FIGS. 2 and 3 are taken along the lines ■-■ and ■-■ in FIG. 1.
The line cross-sectional view and FIGS. 4 and 5 are explanatory diagrams showing the situation in which pressure oil is trapped in the gear. 2.Total...gear, 8-11...bush, FH...
High pressure area, L...Low pressure area, 27...High pressure introduction hole, 16...Discharge hole, 28...High pressure outlet hole, 29.
... recess, 21... passage.

Claims (1)

[Claims] 1. A seal is provided on the outer surface of the bush or side plate provided on the side of the gear, that is, on the side opposite to the side that contacts the gear, to separate the high pressure area and the low pressure area,
High-pressure oil, which is the oil trapped in the gear, is introduced into this high-pressure area through a high-pressure introduction hole formed in the bushing or side plate, and into the low-pressure area, a low-pressure introduction hole also formed in the bushing or side plate is introduced. Through,
In a gear pump or motor with a pressure balance structure that guides low-pressure oil on the suction side and maintains a small gap between the gear and the bush or side plate, a passage is provided on the outer periphery of the seal that separates the high-pressure area and the low-pressure area. A gear pump or motor having a structure in which the high-pressure introduction hole is opened into the passage, and pressure oil from the high-pressure introduction hole is guided to the high-pressure outlet hole via the passage.