JPH06317261A - Gear pump motor - Google Patents

Abstract

PURPOSE:To reduce an oil quantity reaching an oil seal, and prevent degradation or breakage or the like of this by forming a notch groove on the gear side surface of a movable side plate arranged on the oil seal side so as to communicate a part corresponding to a low pressure area on the gear side surface directly with a low pressure chamber. CONSTITUTION:A pair of gears 4 and 5 meshing with each other are housed in a hole 11 formed inside of a body 1. The side surfaces of both gears 4 and 5 are sealed movably slidingly by pressure balancing grooves 31a and 32a of movable side plates 31 and 32. A driving shaft 41 and a driven shaft 51 are pivoted by bearing holes 21, 22, 61 and 62 formed inside of both front and rear covers 2 and 7 to cover the body 1. A part of oil transferred to a high pressure chamber 9 from a low pressure chamber 8 is introduced to the bearing holes 21, 22, 61 and 62, and bearings are self-lubricated. In this way, a notch groove 10 is formed on the gear side side surface 31c of the movable side plate 31 arranged on the oil seal 7 side so as to communicate a part corresponding to a low pressure area L of the gear side surfaces 4a and 5a directly with the low pressure chamber 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump / motor which can be used as a hydraulic source for various machines including agricultural machines such as tractors and combine harvesters, general industrial machines such as table lifters and mini excavators. (Hereinafter, simply described as a pump).

[0002]

2. Description of the Related Art A general structure of a gear pump is a pair of gears that are housed in a hole provided in a body in mesh with each other.
A movable side plate having a pressure balance groove for slidingly sealing the side surfaces of those gears, and a cover for sealing the body hole.
A drive shaft and a driven shaft for supporting the both gears in a bearing hole provided in the cover penetrating the side plate, and an oil seal arranged at the drive shaft penetrating end of the cover are provided.
When both gears are driven to rotate in reverse synchronously via the drive shaft, the side where the teeth of both gears are separated is the low pressure chamber, and the side where the teeth are meshed is the high pressure chamber. The oil is continuously transferred continuously, and at that time, a part of the oil is circulated in the bearing hole to self-lubricate the bearing.

[0003]

However, the conventional structure has a problem that the oil seal is apt to be deteriorated and damaged at an early stage. Specifically, the pressure-balance type movable side plate is provided with a pressure balance groove on the side opposite to the gear side along the high-pressure region. Press it to the side and, as a result,
By balancing the hydraulic pressure from the high pressure region and the pressure, the side surface of the gear is slidably sealed and the volume efficiency is improved. If the pressing force at that time is too strong, the sliding resistance increases, resulting in a loss in mechanical efficiency. Therefore, the pressing force is not set to a very large value. Therefore, the oil leakage through the sliding surface is scheduled to some extent from the beginning. Further, after the oil flows through the sliding surface, it also serves as a lubricating oil that enters the bearing hole and lubricates the bearing. Therefore, there is a surface that is actively used to have a self-lubricating function. However, since the amount of oil leakage is quite large, the amount of oil that reaches the oil seal through the bearing hole becomes excessive, and extra pressure is applied to the oil seal, which causes easy deterioration and damage. ing. Therefore, in the past, a hole was made from the oil seal to the low pressure chamber, but this hole cannot be made too large due to space and strength restrictions, and the effect is sufficient to remove the oil filling the oil seal. There is no. Therefore, the conventional pump still has external leakage through the oil seal due to deterioration and damage of the oil seal, and some measures for protecting the oil seal are desired.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a gear pump which effectively prevents the deterioration and damage of the oil seal and prolongs the life of the entire pump. To aim.

[0005]

The present invention adopts the following constitution in order to achieve the above object.

That is, the gear pump according to the present invention includes a pair of gears that are housed in mesh with each other in a hole provided in a body that is integral with a front cover, and a pressure balance that slides and seals the side surfaces of the gears. A movable side plate having a groove, a front cover and a rear cover for sealing the body hole, a drive shaft and a driven shaft for supporting the both gears in bearing holes provided in both covers through the side plates, and a front An oil seal disposed at the drive shaft penetrating end of the cover, so that a part of the oil transferred from the low pressure chamber to the high pressure chamber is circulated in the bearing hole to self-lubricate the bearing. In the configured one, the side surface of the side plate disposed on the oil seal side is provided with a notch groove that directly communicates a portion of the side surface of the gear substantially corresponding to the low pressure region with the low pressure chamber. That.

[0007]

When such a notch groove is provided, when the oil that has come out of the high pressure region and once flows out to the sliding surface between the gear side surface and the gear side surface of the side plate is about to flow into the bearing hole, The portion enters the cutout groove and is directly returned to the low pressure chamber through the cutout groove. Therefore, the amount of oil flowing into the bearing hole can be adjusted depending on the setting of the size of the groove, and it is possible to prevent the problem that a large amount of oil reaches the oil seal and fills up.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, this gear pump comprises a body 1 and a front cover 2 which are integrally formed by a die casting method. The inner end of an eyeglass-shaped hole 11 provided in the body 1 is The lid is sealed by the front cover 2 from the beginning of molding. The front cover 2 is provided with bearing holes 21 and 22 at two locations.
Bushings 21a and 22a are fitted in the. And
The first movable side plate 31 is accommodated at the inner end of the body hole 11,
Then, the bushes 21a, 22a of the front cover 2 are made to pass through the movable side plate 31 of the drive shaft 41 to which the drive gear 4 is fixed in advance and the driven shaft 51 to which the driven gear 5 is fixed.
And the two gears 4 and 5 in that state.
They are housed in the housing 1 in mesh with each other. Further, the other second movable side plate 32 paired with the first movable side plate 31 is arranged on the outer end surface of the body 1, and in that state,
A rear cover 6 covers the outer end surface of the body 1. The rear cover 6 is also provided with bearing holes 61, 62 at two locations, and the bushes 61a, 62 are provided in the bearing holes 61, 62, respectively.
a is fitted so that the drive shaft 41 and the driven shaft 52 are supported by the bushes 61a and 62a in a lid-sealed state. An oil seal 7 is incorporated at the drive shaft penetrating end of the front cover 2 to prevent the oil leaking through the inner circumference of the bush 21a from leaking to the outside. In addition, the movable side plates 31 and 32 described above are provided with pressure balance grooves 31a and 32a in their high-pressure-corresponding regions on their counter gear side surfaces 31b and 32b, and these pressure balance grooves 31a and 32a are provided on the gear side surfaces 31c and 32c. By introducing high-pressure oil from above, the movable side plates 31 and 32 are pressed against the side surfaces 4a and 5a of the gears 4 and 5, and as a result, the pressure of the hydraulic biasing force from the gears 4 and 5 side is balanced. There is. This keeps the mechanical sliding resistance at a small value and also plays the role of improving the volumetric efficiency by slidingly sealing the gear side surfaces 4a, 5a.

Then, through the drive shaft 41, both gears 4, 5
2 is driven in a synchronous reverse rotation, the internal space of the body on the side where the teeth of both gears 4 and 5 gradually separate from each other becomes the low-pressure chamber 8 as shown in FIG. 2, and the internal space of the body on the side where the teeth gradually mesh with each other. The high-pressure chamber 9 is formed, and oil is continuously transferred from the low-pressure chamber 8 to the high-pressure chamber 9, and at the same time, a part of the oil is circulated to the inner periphery of the bushes 21a, 61a, 22a, 62a described above. The sliding surfaces between the bushes 21a and 61a and the drive shaft 41 and the sliding surfaces between the bushes 22a and 62a and the driven shaft 51 are self-lubricated. That is, this self-lubricating system passage is formed from the tooth groove in which high pressure oil is confined to the gear side surface 4
a, 5a and gear side surfaces 31c, 3 of the movable side plates 31, 32
The oil leaked to the sliding surface with 2c is replaced by the bushes 21a, 61
It is made to flow into the inner circumferences of a, 22a, and 62a, flow along the drive shaft 41 or the driven shaft 51, and then be returned to the low-pressure chamber 8. Particularly in the drive shaft 41, the oil flowing along the bush 21a reaches the oil seal 7 once.
As shown in FIGS. 3 and 4, a hole 8a is formed in advance in the low pressure chamber 8 so that the oil reaching the oil seal 7 is returned to the low pressure chamber 8 through the hole 8a. It is a thing.

In this embodiment, the gear side surface 31c of the side plate 31 disposed on the oil seal 7 side is further provided on the gear side surface 4c as shown in FIGS.
a and 5a, a notch groove 10 (a portion shown by meshing) for directly communicating a portion substantially corresponding to the low pressure region L with the low pressure chamber 8
Is provided. More specifically, the notch groove 10 has a partition line Q that is set slightly closer to the low pressure chamber 8 than the high and low pressure partition line P and the shaft penetrating side plate 31 with respect to the gear-side side surface 31c that is flush with the related art. In the region surrounded by the holes 31d and 31e, the partition line X substantially corresponding to the meshing position of the gears 4 and 5, and the low-pressure chamber 8, a thickness defect portion having a constant depth is formed. Then, when the movable side plate 31 is brought into sliding contact with the gear side surfaces 4a, 5a, a gap corresponding to the notch groove 10 formed therebetween is formed, and the gap is substantially formed in the low pressure region L of the gear side surfaces 4a, 5a through the gap. The corresponding portion is directly connected to the low pressure chamber 8.

When such a notch groove 10 is provided, the oil that has come out of the high pressure region H and once flowed out to the sliding surface between the gear side surface 4a and the gear side surface 31c of the side plate 31 flows into the inner circumference of the bush 21a. When trying to do so, a part of the oil enters the notch groove 10 as shown by the arrow in FIG.
It will be directly returned to the low pressure chamber 8 through 0. Therefore, the amount of oil that flows into the inner circumference of the bush 21a and reaches the oil seal 7 can be limited, and the oil seal 7 can be effectively protected from damage.

Note that such a cutout groove may be provided in the side plate on the side opposite to the oil seal. In addition, the shape of the notch groove, etc.
Various modifications can be made without departing from the spirit of the present invention.

[0014]

As described above, in the gear pump of the present invention, the side surface of the side plate disposed on the oil seal side is directly communicated with the low pressure chamber at a portion substantially corresponding to the low pressure region of the gear side surface. With the configuration in which the notch groove is provided, a part of the oil that has flowed out of the high pressure region and once flows out to the sliding surface between the gear side surface and the gear side surface of the side plate is directly returned to the low pressure chamber through the notch groove,
The amount of inflow into the bearing hole can be limited. for that reason,
Depending on the size of the groove, the amount of oil reaching the oil seal can be reduced, the oil seal can be protected from deterioration and damage, and the inconvenience of the pump going down due to external leakage can be effectively prevented.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

[Explanation of Codes] 1 ... Body 2 ... Front cover 4, 5 ... Gears 4a, 5a ... Gear side surface 6 ... Rear cover 7 ... Oil seal 8 ... Low pressure chamber 9 ... High pressure chamber 10 ... Notch groove 11 ... Holes 21, 22, 61 , 62 ... Bearing holes 31, 32 ... Movable side plates 31a, 32a ... Pressure balance groove 31c ... Gear side surface 41 ... Drive shaft 51 ... Driven shaft

Claims (1)

[Claims] 1. A pair of gears housed in meshed with each other in a hole provided in a body integral with a front cover, and a movable side plate having a pressure balance groove for slidingly sealing the side faces of the gears. A front cover and a rear cover for sealing the body hole, a drive shaft and a driven shaft for supporting both gears through bearing plates provided in both covers through the side plates, and a drive shaft penetrating end of the front cover. A gear pump / motor comprising: an oil seal provided, and configured to allow a part of the oil transferred from the low pressure chamber to the high pressure chamber to flow through the bearing hole to self-lubricate the bearing. A gear pump / motor, characterized in that a notch groove is provided on a side surface of the side plate disposed on the oil seal side on the side of the gear to directly communicate a portion of the side surface of the gear substantially corresponding to the low pressure region with the low pressure chamber.