JPS6321038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for preventing a seal member of a gear pump or motor from moving or breaking under high pressure load.

Particularly in recent gear pumps, it has become common for the bush or side plate (pressure plate) to have a loading balance function.
In order to provide this loading balance function, the back surface of the bush or side plate (the side opposite to the gear) is divided into a high pressure area and a low pressure area by a sealing member. In order to maintain a more delicate loading balance or to use extremely thin side plates, an intermediate pressure area is increasingly provided in addition to the above two areas.

FIG. 1 is a schematic diagram of a conventional gear pump provided with an intermediate pressure area 1. FIG.

That is, FIG. 1 shows a part of the side surface of the mounting flange or cover of the gear pump, and the side surface is divided by the seal member 2 into a high pressure area 3, an intermediate pressure area 1, and a low pressure area 4. There is.

The intermediate pressure area 1 and the low pressure area 4 surrounded by the sealing member 2 protrude toward the front in the drawing, but the drawbacks of this conventional structure are as follows.

That is, the sealing member 2 is not necessarily fixedly fitted due to dimensional tolerances in each part, and there is some wobbling. Therefore, when a high pressure is applied, the sealing member 2 moves in the direction of arrow 5 in FIG. 1 and becomes deformed. If the seal member 2 moves in this way, parts A to C in Figure 1 will be particularly deformed, which will not only disable the pressure balance function and cause oil leaks, but also cause severe damage. In that case, please refer to Part A~ above.
In some cases, one of the C portions was broken.

In this invention, a high pressure introduction groove is formed at a predetermined location of a seal member, and high pressure is also introduced to the seal member located on the low pressure area side through the introduction groove to prevent movement, that is, deformation of the seal member. This is what I did.

This will be explained below with reference to embodiments shown in FIGS. 2 to 6.

The gear pump has gears 13 and 14 inserted into the gear hole 12 of the body 11, and
1 is covered on both sides with a cover 15 and a mounting flange 16. And gears 13 and 14
The shaft of the shaft is supported by the cover and mounting flange, while side plates 17 and 18 are interposed between the shaft and the gears 13 and 14.

In this embodiment of the gear pump, only the mounting flange 16 side has a loading balance function, so only the mounting flange 16 side will be described below.
However, if the cover 15 side is to have the above-mentioned balance function, the cover 15 side may have the same structure as the mounting flange 16 side described below.

The inner surface of the mounting flange 16, that is, the contact surface 19 side with the body 11 has a structure shown in FIG. 3.

Although a concave portion 20 is formed on the inner surface,
The outer periphery of this concave portion 20 maintains a positional relationship that corresponds to the outer side of the gear hole 12, suction hole 21, and discharge hole 22 formed in the body 11.

Within this concave portion 20, portions corresponding to the low pressure area L and intermediate pressure area M are made to protrude to the same level as the contact surface 19, and a sealing member S, which will be described later, is fitted around each of these areas L and M. Grooves 23 to 25 are formed. Further, a similar protrusion 26 is formed at a position substantially corresponding to the discharge hole 22 on the high pressure area H side, and a groove 27 is formed between the protrusion 26 and the outer edge of the recess 20. There is.

Mounting flange 16 as described above
A sealing member S shown in FIGS. 5 and 6 is fitted into the housing, and the outer shape of this sealing member S is made to match the outer circumferential shape of the concave portion 20, and also to surround the required portions around the gear shaft and the intermediate pressure area M. We have a relationship where we

Of this seal member S, the low pressure area L
The portion 28 that fits into the groove 23 on the side, ie, the portion that seals the outside of the low pressure area, is narrower than the width of the groove 23. Therefore, when the seal member S is fitted into the mounting flange 16, the remaining portion 29 is maintained within the groove 23.

In addition, at required locations on the back side of this seal member S,
A high pressure introduction groove 30 is formed.

As is clear from FIG. 6, this high pressure introduction groove 30 is connected to the high pressure area H side and the low pressure area L side via a portion 31 that is fitted into the groove 24, that is, a portion that seals the outside of the intermediate pressure area. The high pressure introduction groove 30 is formed up to a portion 32 that is fitted into the groove 25, that is, a portion that seals the inside of the intermediate pressure area.

The relative relationship between the body 11 and the mounting flange 16 that holds the seal member S is as shown in FIGS. 3 and 4.

That is, the outer periphery of the seal member S is located outward from the gear hole 12, suction hole 21, and discharge hole 22 of the body 11, and the low pressure area L is in close contact with the side surface of the body 11 on the groove 23 side. The relationship is such that the metal seal portion 33 is held.

However, when the mounting flange 16 is brought into close contact with the body 11, the back surface of the side plate 18 is divided into a high pressure area H, an intermediate pressure area M, and a low pressure area L by the seal member S. When the pump is rotated in this state, a corresponding pressure is introduced into each area, as in the conventional case.

When pressure is introduced into each area as described above,
The high pressure in the high pressure area H flows into the high pressure introduction groove 30 and also flows into the remaining portion 29 of 23 via the groove 30. In this way, the remaining part 29
The after-pressure oil that has flowed into the low pressure area L does not leak into the low pressure area L due to the sealing function of the metal seal portion 33.

Therefore, since the high pressure acts on each part of the seal member S that partitions the intermediate pressure area and the low pressure area, the seal member as a whole is balanced by the high pressure and does not move.

Further, since the seal member S is prevented from moving by the pressure balance, the groove widths of the grooves 23 to 25 described above do not need to be made very precise. Therefore, a backup 34 can be inserted which surrounds the low pressure area L. This is because when attempting to fix the seal member by simply fitting it into the groove as in the past, if a back-up is inserted, the dimensional tolerance of the groove becomes even larger, making the above-mentioned drawbacks even more noticeable. In this invention, the grooves 23 to 2
This is because the dimensional tolerance of No. 5 does not pose much of a problem.

As is clear from the above description, according to the seal structure recited in claim 1, the seal member is balanced by the high pressure in the high pressure area, so that the seal member does not move as in the conventional case.

Therefore, the sealing member is not deformed or broken, and can exhibit the desired loading balance function.

According to the seal structure recited in claim 2,
Since the high pressure introduction groove is also formed around the intermediate pressure area, deformation and breakage of the sealing member can be more effectively prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the seal structure of a conventional gear pump, FIGS. 2 to 6 show an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the gear pump.
Fig. 3 is an inner side view of the mounting flange with the seal member removed, Fig. 4 is a sectional view taken along the line of Fig. 2, Fig. 5 is a front view of the seal member, and Fig. 6 is a back view of the mounting flange. FIG. 7 is a cross-sectional view taken along the line of FIG. 3 with the seal member attached. 11...Body, 13,14...Gear, 15...
...Cover, 16...Mounting flange, 1
7, 18... Side plate, H... High pressure area, M... Intermediate pressure area, L... Low pressure area, S... Seal member, 23-25, 27... Groove, 28... Seal the outside of the low pressure area. Part to be done, 29... Remaining part, 3
0... High pressure introduction groove, 31... Part that seals the outside of the intermediate pressure area, 32... Part that seals the inside of the intermediate pressure area, 33... Metal seal part.

Claims (1)

[Claims] 1. A gear pump in which the back surface of a side plate provided on the side surface of a gear is divided into a high pressure area, an intermediate pressure area, and a low pressure area by a sealing member fitted into either a cover or a mounting flange, or both. Or, in the motor, a groove into which a sealing member is fitted is formed at a required location on the side surface of the cover or mounting flange, and the portion of the sealing member that seals the outside of the low pressure area is made narrower than the width of the fitting groove. When this sealing member is fitted, a remaining portion is formed in the groove, and a metal sealing portion is formed slightly inwardly from this remaining portion and in close contact with the side surface of the body. A sealing structure for a gear pump or motor, comprising a high-pressure introduction groove that communicates the high-pressure area with the remaining portion via a portion that seals the intermediate-pressure area. 2. The sealing structure for a gear pump or motor according to claim 1, wherein the high pressure introduction groove is formed in a portion that seals the outside and inside of the intermediate pressure area.