JP2000249077A - Gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve lubrication operation at the bearing of the rotary shaft of a gear. SOLUTION: A side plate 7a and an annular sealant 10 having approximate the same thickness as that of a 3-shaped sealant 9a are disposed in a gap between a front cover and a rear cover in a manner to surround a slide part between shafts 5a and 5b and a bearing. Oil leaking through a gap between the shafts 5a and 5b and the side plate 7a toward the bearing is guided to a slide part between the shafts 5a and 5b and the bearing and lubrication operation is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a gear pump used for construction machines, machine tools, agricultural machines, industrial vehicles and the like.

[0002]

2. Description of the Related Art Conventionally, gear pumps are shown in FIGS.
As shown in AA section of FIG.
1, a driving gear 32 and a driven gear 33 meshing with the driving gear 32 are accommodated. Side plates 35, 36 are provided on the side surfaces of both gears, and rotating shafts 51, 61 of the gears are mounted on bearings 52, 53,
Bearings 62 and 63 are provided.
A rear cover 40 accommodating the bearings 3 and 63 and a front cover 41 accommodating bearings 52 and 62 are provided at the front end of the body. The body 30, the front cover 4
1 and the rear cover 40 are collectively referred to as a case.

[0003] Oil leakage inside the gear pump constructed as described above can occur at three points, namely, a tooth tip, a side surface, and a tooth surface. The oil leakage occurs between the front cover 41 and the side plate 35 and the rear cover 40.
And the side plate 36, elastic sealing members 43 and 44, respectively.
Is provided to partition the high-pressure side (discharge side) H and the low-pressure side (suction side) L to prevent oil leakage in the side plates 35 and 36.

As shown in FIG. 4, in such a gear pump, in order to increase the suction flow rate on the low pressure side, a large opening 37 is provided in the side plate 35 near the low pressure side, so that the suction flow rate is reduced. We are trying to increase. The elastic sealing material 43 is also formed in a so-called three-letter shape that is interrupted before the opening 37. The rear cover 40
The same applies to the side plate 36 on the side.

[0005]

By the way, the precision of various parts of the gear pump has been improved with the recent improvement of processing accuracy, and oil leakage from gaps between parts due to processing errors has been reduced. Although this contributed to the improvement of the pump efficiency, the lubricating action due to the conventional leaked oil was reduced.

In particular, the lubrication between the rotating shaft and its bearing is
Such leakage oil largely depends on the need for downsizing of bearings in response to recent demands for downsizing gear pumps. Improving the lubrication of bearings is an urgent problem to be solved.

However, conventionally, as described above, 3
In a gear pump using a U-shaped elastic seal material, a gap is formed between the compressed elastic seal material and the body case, so oil leaking into the gap between the side plate and the body case through the shaft hole in the side plate However, since the oil flows into the low pressure side from the broken portion of the elastic seal material, that is, from the opening 37, the amount of oil flowing through the bearing is small and the amount of oil is insufficient for lubrication.

An object of the present invention is to solve such problems and to lubricate bearings in a gear pump in which pump efficiency is improved with improvement in machining accuracy.

[0009]

The gear pump according to the present invention comprises:
A side plate that slides on the gear side surface on both sides of the pair of gears and cuts off the suction port side, and a case that accommodates a bearing on the opposite gear side of the side plate and supporting a rotation shaft of both gears, A gear pump having a three-letter seal material that partitions the discharge port side and the suction port side in a gap between the side plate and the case, and a three-letter seal material in a gap between the side plate and the body. By arranging an annular sealing material having substantially the same thickness so as to surround the sliding portion between the rotating shaft and the bearing, the oil flowing out toward the bearing through the gap between the shaft and the side plate is rotated. It is characterized in that it is configured to guide to a sliding portion between a shaft and a bearing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. 1 and 2 (cross section taken along line AA in FIG. 1). In this gear pump, as shown in FIG. 1, a pair of spur gears 4a and 4b meshing with each other are fitted in a gear chamber 3a in a body 3 body having both open ends sealed by a front cover 1 and a rear cover 2. And the side surfaces of both gears 4a and 4b are sealed with side plates 7a and 7b, and a driving side rotating shaft 5a supporting one of the gears 4a and a driven side rotating shaft 5b supporting the other gear 4b. The bearings 6a and 6b and the bearings 8a and 8b disposed in the two covers 1 and 2 are rotatably supported. The drive-side rotating shaft 5a extends outward through the front cover 1 and the rear cover 2, and one extending end is connected to a power source (not shown). The body 3, the front cover 1, and the rear cover 2 are collectively called a case.

A suction port (low pressure side) L is provided on the side where the teeth are separated from the meshing position of the two gears 4a and 4b, and a discharge port (high pressure side) is on the side where the teeth meet toward the meshing position. H is provided. When the power is applied to the rotating shaft 5a, the power is also transmitted to the rotating shaft 5b. As a result, the gears 4a and 4b rotate synchronously and reversely with each other to discharge the oil sucked from the suction port L side. The transfer is made to the exit H side. Further, the rotating shaft 5a and the rotating shaft 5b are supported by bearings 6a and 6b, respectively.

By the way, as shown in FIG.
Is provided with an opening 7h to increase the suction amount on the low pressure side L. In the side plate 7a, a three-shaped elastic sealing material 9a interrupted at an opening is fitted in a groove provided in the side plate 7a, and a high pressure side H and a low pressure side are formed between the side plate 7a and the front cover 7a. L. The rear side plate 7b is also provided with an elastic sealing material 9b.

Further, a side plate 7 is provided inside the elastic sealing material 9a.
annular sealing material 10 surrounding the shaft holes of shafts 5a and 5b in FIG.
Is formed in the side plate 7a. The crushing margins of the elastic sealing material 9a and the annular sealing material 10 are substantially the same, and these two sealing materials are configured to simultaneously exert a sealing function.

When the gear pump starts driving,
Oil is sucked in from the low pressure side L, and is conveyed and discharged to the high pressure side H by the gears 4a and 4b. During the transportation of the oil by the gears 4a and 4b, a small amount of oil is removed from the side plates 7a by the gears 4a and 4b.
And leaks to the bearings 6a and 6b through the gap between the shafts 5a and 5b and the side plate 7a. Since the leaked oil is sealed by the annular seal member 10, the oil is supplied to the bearings 6a and 6b so that the oil does not leak outside from the annular seal member 10. Therefore, since the bearings 6a and 6b are lubricated by the oil supplied in this manner, the shafts 5a and 5b rotate without hindrance to the bearings 6a and 6b, and the pump operation is performed.

As described above, since a sufficient lubricating action is performed in the bearing, seizure is reliably prevented, and the life of the bearing is extended. Therefore, costs and labor required for maintenance and the like are reduced.

In this embodiment, the elastic sealing material or the annular sealing material is fitted in the groove provided in the side plate, but the front cover and the rear cover may be provided with a groove.

[0017]

As described above, according to the present invention, even if the leakage oil which has contributed to the lubricating action of the bearing decreases with the improvement of the processing accuracy, the leakage can be reduced by using the sealing material. The oil can be sufficiently guided to the bearing portion, and the pump efficiency can be improved without hindering the lubrication operation. In addition, the bearing can be shortened without causing any trouble in the lubricating action.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a gear pump main body of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view of a conventional gear pump main body.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

[Explanation of symbols]

 5a shaft 5b shaft 6a bearing 6b bearing 7a side plate 7b side plate 9a 3-shaped elastic seal material 10 annular seal material

Claims (1)

[Claims] 1. A gear pump configured to convey oil sucked from a suction port by a pair of gears and discharge the oil to a discharge port. A side plate with a cut-out side of the suction port, a case which is located on the opposite side of the side plate and supports a rotating shaft of both gears, and a gap between the side plate and the case, the discharge port side and the suction side. In the gear pump provided with a three-letter seal material for partitioning the seal member, an annular seal material having substantially the same thickness as the seal material is provided in a gap between the side plate and the case. A gear pump characterized by being disposed so as to surround a sliding portion.