JPH10122161A - Gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the vibrations and noises caused by the containment occurring in the closed region formed by both side plates and meshing gear teeth in a gear pump and prevent the abrasion of the portions supporting spindles. SOLUTION: The spindles 31, 41 of a driving gear and a driven gear are supported by the support holes 31, 41 provided on a pair of side plates 12, 12 partitioning a gear chamber. Each side plate 12 is provided with a closed region formed by both side plates 12, 12 and meshing gear teeth and the passages 82, 83 communicating the support holes 31, 41. The occurrence of a high pressure due to containment not resolved by the conventional clearance grooves 63, 64 provided off the meshing center position K can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump which operates by rotating a pair of gears meshing with each other.

[0002]

2. Description of the Related Art Conventionally, gear pumps have been used in various industrial fields as small and lightweight pumps having a simple structure. As a structure of this kind of gear pump, a pair of side plates are fitted into a cavity inside a housing to define a gear chamber, and a pair of gears meshing with each other are housed inside the gear chamber, and a support shaft of each gear is formed. In general, a type in which a working fluid suction chamber and a discharge chamber are formed inside the gear chamber with a fitting position between the two gears while being fitted and supported by support holes formed in each side plate.

On the other hand, in recent years, there has been a demand for a high-pressure type gear pump. However, as the pressure becomes higher, the support shaft is pushed in one direction in the support hole and becomes eccentric, so that the portion supporting the support shaft is worn out. As a result, there is a problem that the pump efficiency is reduced. Conventionally, there is a gear pump in which a spiral groove is provided in a support shaft or a support hole in order to lubricate the inside of the support hole, and oil is forcibly drawn into the support hole as the support shaft rotates (for example, there is a gear pump). See JP-A-4-1055985). However, this gear pump has a problem that when the pump rotation speed is low, even if the pump load is large (the pressure on the discharge chamber side is high), the amount of oil supplied to the support hole is small and lubrication is insufficient. .

[0004] By the way, in the meshing portion of the gears, oil is trapped in a closed area formed by each side plate and each gear tooth meshing with each other (a so-called trapping phenomenon occurs). As a result, a very high pressure is generated when compressed, resulting in a problem that vibration and noise are generated. Therefore, a pair of clearance grooves are formed on the side surface of the gear on the side of the gear on both sides of the engagement center position of the two gears so that the high pressure generated in the engagement portion by each clearance groove is released to the suction chamber side and the discharge chamber side. A gear pump is provided (for example, see Japanese Unexamined Patent Publication No.
See No. 8-17109. ). However, in this gear pump, it is said that it is difficult to completely prevent the close-up near the center position of the engagement because there is a limit in the arrangement area of each relief groove.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent vibration and noise caused by closing in the vicinity of the center position of engagement of gears, and to prevent wear of a portion supporting a support shaft of the gear, thereby achieving excellent durability. To provide a gear pump.

[0006]

According to a first aspect of the present invention, there is provided a gear pump in which a gear chamber is defined by fitting a pair of side plates into a cavity inside a housing. A pair of gears meshing with each other are housed therein, and the support shaft of each gear is fitted and supported by a support hole formed in each side plate, and the working fluid of the working fluid is sandwiched between the meshing positions of both gears inside the gear chamber. A gear pump having a suction chamber and a discharge chamber, wherein a flow path is formed in the side plate to communicate a closed region formed by both side plates and gear teeth meshing with the support hole. It is.

In this configuration, the high-pressure working fluid to be confined in the vicinity of the center position where the two gears mesh with each other is guided to the fitting gap between the support shaft and the support hole via the flow path, and performs a lubricating action. Since the fluid is guided from a portion that generates high pressure regardless of the pump rotation speed, fluid can be supplied for lubrication even when the pump rotation speed is low, so that wear can be prevented. Further, since the closing pressure in the vicinity of the meshing center position of the two gears can be released, the generation of vibration and noise due to this can be prevented.

Further, when the flow path is opened to the eccentric side fitting region of the inner peripheral surface of each support hole, the following advantages are provided. That is, as the pressure of the discharge chamber becomes higher, the force for pushing the support shaft from the discharge chamber side toward the suction chamber side becomes stronger. Therefore, the support shaft is eccentric to the support hole so as to approach the suction chamber side, and The gap in the eccentric fitting area on the inner peripheral surface of the hole tends to be narrow, which is a severe condition for lubrication. On the other hand, according to the present invention, the fluid can be supplied to the side where the severe condition is obtained at the time of the high pressure, so that the effect of preventing the wear is further improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view of a gear pump according to an embodiment of the present invention, and FIG.
It is sectional drawing which follows a line and hatching is omitted. With reference to these figures, the present gear pump is provided on both sides of a main body cylinder 10 having a cavity having an oval cross section penetrating a central portion thereof.
A pair of cover plates 11 screwed to cover the entire surface
The housing 1 is configured to be closed by the housing 1. Inside the housing 1, a gear chamber 14 is defined between a pair of side plates 12 made of, for example, an aluminum alloy inserted from both sides of the hollow portion. A drive gear 3 and a driven gear 4 that form a pair are arranged. Reference numeral 13 denotes an O which is interposed between the lid plate 11 and the side plate 12 to seal the gear chamber 14.
It is a ring.

Inside the gear chamber 14, a pair of support shafts 30, 40, which are supported at both ends, are respectively supported by support holes 31, 41 formed in the side plates 12 in pairs.
Are located on the axes of the semicircular portions on both sides of the gear chamber 14 having an oval cross section, respectively, and are installed in parallel with each other. One support shaft 3 supported by a pair of support holes 31
Numeral 0 extends outside through one cover plate 11 and constitutes a drive shaft which is rotated and driven by a driving force from a power source such as a motor (not shown) transmitted to the extended end.
The drive gear 3 is mounted on the support shaft 30 so as to be integrally rotatable inside the gear chamber 14. An oil seal 17 is arranged at a portion where the support shaft 30 penetrates the cover plate 11.

The other support shaft 40 supported by the pair of support holes 41 is connected to the support holes 4 of each side plate 12.
1 constitutes a driven shaft having a shaft end. The driven gear 4 is mounted on the support shaft 40 inside the gear chamber 14. When the driven gear 4 is mounted on the support shaft 40, rotation around the axis may be restricted or rotation around the axis may be allowed.
The driven gear 4 meshes with the drive gear 3 in a plane including the axis of the support shafts 30, 40, and together with the support shaft 40 (or of the support shaft 40) with the rotation of the drive gear 3 driven by the support shaft 30. It is driven (without rotation).

In FIG. 2, the directions of rotation of the drive gear 3 and the driven gear 4 interlocked with the drive gear 3 are indicated by arrows. A discharge chamber 6 is formed on the suction port chamber 5 on the side opposite to the rotation direction. These suction chamber 5 and discharge chamber 6
Through a suction port 15 and a discharge port 16 which are opened at the corresponding positions 0, a suction destination and a discharge destination (not shown) outside the housing 1 are respectively connected.

With such a configuration, the working fluid introduced into the suction chamber 5 through the suction port 15 is received between the teeth of the driving gear 3 and the driven gear 4 facing the suction chamber 5, and the two gears 3, 4 By the rotation of, the sheet is conveyed in a state of being sealed between the respective teeth and the inner peripheral surface of the main body tube 10 and sent out to the discharge chamber 6. The drive gear 3 and the driven gear 4 that have finished sending out to the discharge chamber 6 face the suction chamber 5 through the meshing position of the two gears 3 and 4, receive the working fluid in the suction chamber 5 again, and discharge the discharge chamber. It works to send out to the 6 side.

During the operation of the gear pump performed as described above,
Inside the gear chamber 14, the low pressure inside the suction chamber 5
It rises with the rotation of the driving gear 3 and the driven gear 4,
A pressure distribution that reaches a high pressure inside the discharge chamber 6 is generated, and a pressing force in a direction indicated by a black arrow in FIG. 2 acts on the driving gear 3 and the driven gear 4. As a result, the support shafts 30 and 40 of the drive gear 3 and the driven gear 4 are moved toward the suction chamber 5 side.
Each of the side plates 12 is pressed against the inner peripheral surfaces of the support holes 31 and 41, and comes into contact between the support shafts 30 and 40 and the inner peripheral surfaces of the support holes 31 and 41 via an oil film. In particular, the frictional resistance in the portion tends to increase under low rotation speed where the formation of an oil film is not performed favorably, and the wear of the inner surfaces of the support holes 3 and 41 tends to be promoted. On the other hand, in the meshing portion between the driving gear 3 and the driven gear 4, the working fluid is confined between the convex portion of one tooth and the concave portion of the other tooth, generating an extremely high pressure and generating vibration and noise. There is a risk.

In this embodiment, the support shaft 3 of the two gears 3 and 4 is used.
Support holes 31 of the side plate 12 for supporting 0, 40,
By providing an oil passage for guiding the high-pressure working fluid in a region including the meshing center position K (see FIG. 2) of the two gears 3 and 4 on the 41, the lubrication of the support holes 31 and 41 is improved and the closing is performed In order to prevent this, the above-mentioned problem is solved. FIG. 3 is a side view of the side plate 12, and FIG. 4 is a longitudinal sectional view of the side plate.

Referring to FIGS. 3 and 4, annular grooves 61 and 62 surrounding the periphery of support holes 31 and 41 are formed in gear side surface 12a of side plate 12, respectively. Further, on the gear side surface 12a, a clearance groove 63 extending from the meshing position of the two gears 3 and 4 toward the suction chamber 5 and a clearance groove 64 extending toward the discharge chamber 6 are formed. These relief grooves 63 and 64 are used to prevent so-called confinement in which fluid is confined in a closed area formed by each side plate 12 and each meshing gear tooth at the meshing position of both gears 3 and 4. Things.

The escape grooves 63 and 64 are provided so as to avoid the center position K where the gears 3 and 4 mesh with each other, and a predetermined distance is secured between them. This is both escape grooves 6
3 and 64, these escape grooves 63 and 64
This prevents the suction chamber 5 and the discharge chamber 6 from communicating with each other through the through-hole, so that the pump function cannot be performed. The distance between the clearance grooves 63 and 64 separated from each other with the meshing center position K of the gears 3 and 4 interposed therebetween is as narrow as possible in consideration of the dimensional accuracy of each component, the meshing error of the gears 3 and 4, and the like. It is set to be.

On the gear side surface 12a of the side plate 12, at the intermediate position (for example, the center position) between the clearance grooves 63 and 64, that is, in the closed area including the meshing center position K of the gears 3 and 4. There are both escape grooves 6
For example, a conical concave portion 81 is formed corresponding to the region isolated from the support holes 31 and 64.
Flow paths 82 and 83 communicating with each other are formed in the inside 1. Each of the flow paths 82 and 83 is formed on the inner peripheral surface 3 of the support hole 31 or 41.
Eccentric side fitting area P of 1a, 41a (in FIG. 3, inner circumference of support holes 31, 41, located closer to suction chamber 5 than virtual plane 73 including axis 71, 72 of support holes 31, 41) Surface 31a, 41a).

Reference numeral 65 denotes an annular groove 6 corresponding to the eccentric side fitting region P of the inner peripheral surfaces 31a, 41a of the support holes 31, 41.
An escape groove for communicating the portions 1 and 62 with the suction chamber 5 side. A similar relief groove 65 is provided on the opposite gear side surface 12b of the side plate 12 corresponding to each of the support holes 31 and 41. Reference numeral 66 denotes an annular groove for accommodating the O-ring 13.

The high-pressure working fluid that is to be confined in the closed area near the meshing center position K of the two gears 3 and 4 is:
Through the flow paths 82 and 83, the supply can be made to the eccentric side fitting region P of the inner peripheral surfaces 31a and 41a of the support holes 31 and 41. The flow paths 82 and 83 are opened at a substantially central position in the axial direction in the support hole 31, and the working fluid supplied to this portion uniformly flows on both sides in the axial direction and flows into the support holes 31 and 41. After evenly lubricating the entire system,
Through the suction chamber 5.

According to the present embodiment, the high pressure generated in the closed area between the meshing teeth of the driving gear 3 and the driven gear 4, which cannot be prevented by the conventional clearance grooves 63 and 64, is suppressed. , Vibration and noise can be prevented. The combination of the conventional escape grooves 63, 64 and the flow paths 82, 83, which is a feature of the present embodiment, can reliably prevent the generation of high pressure due to confinement. In addition, the high-pressure working fluid to be confined in the closed area can be supplied into the support shaft holes 31 and 41. As a result, the inside of the support holes 31 and 41 can be lubricated and wear can be prevented.

Further, since lubricating fluid is supplied to the eccentric side fitting area P of the support holes 31, 41, which tends to narrow the gap between the support shafts 30, 40 at high pressure, wear is further prevented. effective. Note that the present invention is not limited to the above embodiment, and various changes can be made within the scope of the present invention.

[0023]

According to the first aspect of the present invention, it is possible to prevent vibration and noise caused by the confinement in the closed area formed by the gear teeth meshing with both side plates, and to prevent the high-pressure working fluid in the closed area. Can be supplied into the support hole, so that the inside of the support hole can be lubricated and wear can be prevented.

According to the second aspect of the present invention, the fluid is supplied to the portion of the support hole where the space between the support shaft and the support shaft tends to be narrow at the time of high pressure, so that the wear can be more effectively prevented. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gear pump according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, with hatching omitted.

FIG. 3 is a side view of a side plate.

FIG. 4 is a sectional view of a side plate.

[Explanation of symbols]

 Reference Signs List 1 housing 3 drive gear 4 driven gear 5 suction chamber 6 discharge chamber 12 side plate 14 gear chamber 30, 40 support shaft 31, 41 support hole 31a, 41a inner peripheral surface 82, 83 channel K meshing center position P eccentric side fitting region

Claims (2)

[Claims] A gear chamber is defined by fitting a pair of side plates into a cavity inside a housing, a pair of gears meshing with each other are housed inside the gear chamber, and a supporting shaft of each gear is attached to each side plate. In the gear pump, which is fitted and supported by the formed support holes and has a suction chamber and a discharge chamber for the working fluid with the meshing position of the two gears sandwiched between the gear chambers, the side plates and the side plates mesh with the side plates. A gear pump, wherein a flow path communicating between a closed region formed by each gear tooth and the support hole is formed. 2. The gear pump according to claim 1, wherein said flow path is opened in an eccentric side fitting area of an inner peripheral surface of each support hole.