1. An internal gear pump comprises a hollow pump body, a rotatable annular inner gear ring is arranged in a pump cavity of the pump body, a driving gear meshed with the inner gear ring is arranged in the inner gear ring, the outer diameter of the driving gear is smaller than the inner diameter of the inner gear ring, the axial center of the inner gear ring is offset relative to the axial center of the driving gear, a positioning rod fixedly connected with the pump body is arranged on the outer side of the biting side of the meshing position of the driving gear and the inner gear ring, a floating sealing device is arranged between the meshing position and the positioning rod and comprises a crescent main plate and a crescent auxiliary plate, one end of the crescent main plate, which is close to the positioning rod, is pivoted on the pump body through a pin shaft, the inner side surface of the crescent main plate, which is close to the driving gear, is in arc-shaped fit with the outer periphery of the driving gear, and the outer side surface of the crescent auxiliary plate, which is far away from the crescent main plate, is in arc-shaped fit with the inner periphery of the inner gear ring, the crescent mainboard is close to the lateral surface of crescent subplate with the crescent subplate is close to be equipped with a plurality of elastic sealing mechanism between the medial surface of crescent mainboard, its characterized in that, be equipped with a through-hole in the crescent mainboard at least between the lateral surface, the perforating hole is in the position distance of crescent mainboard medial surface the crescent mainboard be close to the medial surface arc length of locating lever one end with the ratio of crescent mainboard medial surface total arc length is between one fourth to one half, the axial centerline of perforating hole with the perforating hole is in contained angle between the normal of crescent mainboard medial surface position is between 20 to 30, perforating hole axial centerline for normal is to locating lever one side slope, the total area of perforating hole cross section is between 0.4 to 2 square millimeters.

2. An internal gear pump according to claim 1, wherein the through hole is located on the inner side of the crescent main plate at a distance from the arc length of the inner side of the crescent main plate at the end close to the positioning rod to the total arc length of the inner side of the crescent main plate, which is between seven twenties and nine twenties.

3. An internal gear pump according to claim 2, wherein the through hole is located on the inner side surface of the crescent main plate at a distance from the arc length of the inner side surface of the crescent main plate at the end close to the positioning rod to the total arc length of the inner side surface of the crescent main plate, and the ratio of the arc length of the inner side surface of the crescent main plate is two fifths.

4. A crescent gear pump according to claim 1, wherein an angle between an axial centerline of said through bore and said normal is between 23 ° and 26 °.

5. A crescent gear pump according to claim 4, wherein an angle between an axial centerline of said through bore and said normal is between 24 ° and 25 °.

6. A crescent gear pump according to claim 1, wherein the total area of the cross-sections of said through-going bores is between 0.5 and 1 mm.

7. A crescent gear pump according to claim 6, wherein the total area of the cross-sections of said through-going bores is between 0.5 and 0.7 square millimeters.

8. A crescent gear pump according to claim 1, wherein the number of through-holes is 3, 3 of said through-holes being equidistantly arranged, wherein the centrally arranged through-hole is located in the middle of the width of said crescent plate.

9. An internal gear pump according to any of claims 1 to 8, wherein a pilot hole is provided at one end of the through hole, and the pilot hole has a diameter larger than that of the through hole.

10. An internal gear pump according to claim 9, wherein said tooling holes are located at an end of said through bore facing said inside surface of said crescent plate, said tooling holes having a diameter greater than the thickness of the tooth crest of the drive gear.

Background

In the internal gear pump in the prior art, the cavity in the crescent main plate and the crescent auxiliary plate separate the pump body into a high-pressure hydraulic area and a low-pressure hydraulic area, the high-pressure hydraulic area is located on one side of the meshing position of the crescent main plate and the crescent auxiliary plate, the opposite side of the crescent main plate and the crescent auxiliary plate is a low-pressure hydraulic area, and a plurality of elastic sealing mechanisms formed by sealing rods and spring pieces are connected between the crescent main plate and the crescent auxiliary plate. In the actual use process, the contact surface of the inner side of the crescent main plate and the driving gear is quickly abraded, and the sealing rod is also unexpectedly deformed to fail, so that the internal gear pump is damaged in advance.

Disclosure of Invention

In order to overcome the defects, the technical problems to be solved by the invention are as follows: the internal gear pump can improve the pressure difference between the inner side and the outer side of the crescent main plate, thereby delaying the abrasion of the inner side surface of the crescent main plate and the deformation of a sealing rod, and prolonging the service life.

The technical scheme for solving the problems in the prior art is as follows: an internal gear pump comprises a hollow pump body, a rotatable annular inner gear ring is arranged in a pump cavity of the pump body, a driving gear meshed with the inner gear ring is arranged in the inner gear ring, the outer diameter of the driving gear is smaller than the inner diameter of the inner gear ring, the axial center of the inner gear ring is offset relative to the axial center of the driving gear, a positioning rod fixedly connected with the pump body is arranged on the outer side of the biting side of the meshing position of the driving gear and the inner gear ring, a floating sealing device is arranged between the meshing position and the positioning rod and comprises a crescent main plate and a crescent auxiliary plate, one end of the crescent main plate, which is close to the positioning rod, is pivoted on the pump body through a pin shaft, the inner side surface of the crescent main plate, which is close to the driving gear, is in arc-shaped fit with the outer periphery of the driving gear, and the outer side surface of the crescent auxiliary plate, which is far away from the crescent main plate, is in arc-shaped fit with the inner periphery of the inner gear ring, the crescent mainboard is close to the lateral surface of crescent subplate with the crescent subplate is close to be equipped with a plurality of elastic sealing mechanism between the medial surface of crescent mainboard, be equipped with a through-hole at least between the inside and outside surface of crescent mainboard, the perforating hole is in the position distance of crescent mainboard medial surface the crescent mainboard is close to the medial surface arc length of locating lever one end with crescent mainboard medial surface total arc length's ratio is between one fourth to one half, the axial centerline of perforating hole with the perforating hole is in contained angle between the normal of crescent mainboard medial surface position is between 20 to 30, perforating hole axial centerline for normal is to locating lever one side slope, the total area of perforating hole cross section is between 0.4 to 2 square millimeters.

A plurality of inner sealing areas are formed between the tooth grooves of the driving gear and the inner side surface of the crescent main plate, and a plurality of outer sealing areas are separated from a gap between the crescent main plate and the crescent auxiliary plate by an elastic sealing mechanism jointly formed by a sealing rod and a spring piece. Because some small amount of oil is inevitably leaked in the hydraulic pump, the oil pressure of an inner sealing area and an outer sealing area close to the low-pressure hydraulic area to an inner sealing area and an outer sealing area close to the high-pressure hydraulic area is sequentially lifted; the time for the inner sealing area to transfer from the low-pressure hydraulic area to the high-pressure hydraulic area is extremely short, so that less internal oil drainage liquid is obtained, and the oil pressure of the inner sealing area is relatively low; the outer sealing area is fixed, and more inner oil drainage liquid is continuously obtained, so that the oil pressure of the outer sealing area is higher. Based on the above practical phenomena, the inventor searches for an inner side surface balance point on the inner side surface of the crescent main plate according to the oil pressure lifting gradient of each inner sealing area by using a lever principle, and confirms that the ratio of the inner side surface arc length of the crescent main plate close to one end of the positioning rod to the total inner side surface arc length of the crescent main plate is within a quarter-half interval, that is, the outlet position of the through hole on the inner side surface of the crescent main plate is within the interval. Similarly, the inventor searches the balance point of the outer side surface on the outer side surface of the crescent main plate by utilizing the lever principle according to the oil pressure lifting gradient of each outer sealing area, the connecting line between the balance points of the inner side surface and the outer side surface of the crescent main plate is the axial center line of the through hole, and in order to manufacture the through hole conveniently, the axial center line of the through hole is confirmed to incline towards one side of the positioning rod relative to the normal line of the through hole at the position of the inner side surface of the crescent main plate, and the included angle between the axial center line of the through. If the pressure difference between the inner side surface and the outer side surface of the crescent main plate is too large, the inner side surface of the crescent main plate is worn and damaged too early, and the sealing rod is deformed and damaged in advance; if the pressure difference undersize between the inner side surface and the outer side surface of the crescent moon main plate can cause unreliable sealing between the tooth tops of the crescent moon main plate and the driving gear, the oil in a high-pressure hydraulic area leaks back too much, and the reduction of the internal gear meshing is realizedThe working efficiency of the pump is serious, and the working pressure of the internal gear pump can not reach the rated pressure; whether the pressure difference between the inner side surface and the outer side surface of the crescent main plate is proper or not is determined according to the quantity of the through holes and the total oil flow generated by the diameter, therefore, the inventor calculates the total area of the cross section of the through holes according to related parameters=0.6291mm 2; wherein the total flow of through-holes Q = k bAnd k is as follows: the coefficient of the systematic error correction is used,: pressure difference across the through hole=-（Generally, 0.1 to 0.2 MPa),is the pressure at the position of the balance point on the inner side surface of the crescent mainboard,is the pressure at the position of the balance point on the outer side surface of the crescent mainboard,absolute viscosity, l: length of through hole, b: width of the drive gear, h: the side gap of the crescent main board is provided,: the outermost circular linear velocity of the driving gear. Considering the sealing reliability between the crescent main plate and the tooth top of the driving gear, the total area S of the cross section of the through hole is 0.4 to 2 square millimeters.

As a further technical scheme, the ratio of the arc length of the inner side surface of the through hole at the position of the inner side surface of the crescent main plate, which is far away from one end of the crescent main plate close to the positioning rod, to the total arc length of the inner side surface of the crescent main plate is between seven tenths of two and nine tenths of two.

As a further technical scheme, the through hole is located on the inner side surface of the crescent main plate and is away from the inner side surface arc length of one end, close to the positioning rod, of the crescent main plate, and the ratio of the total arc length of the inner side surface of the crescent main plate is two fifths.

As a further technical solution, an angle between an axial center line of the through hole and the normal is between 23 ° and 26 °.

As a further technical solution, an angle between an axial center line of the through hole and the normal is between 24 ° and 25 °. Most preferably, an angle between an axial center line of the through hole and the normal line is 24.68 °.

As a further technical solution, the total area of the cross-section of the through-holes is between 0.5 and 1mm square.

As a further technical solution, the total area of the cross-section of the through holes is between 0.5 and 0.7 mm. In the most preferred embodiment, the total area of the cross-section of the through-holes is 0.6371 square millimeters, i.e. the diameter of the through-holes is 0.52 millimeters.

As a further technical scheme, the number of the through holes is 3, and the 3 through holes are arranged at equal intervals, wherein the through hole arranged in the middle is positioned in the middle of the width of the crescent mainboard. Thus being beneficial to the uniformity of the pressure difference on the two sides of the crescent mainboard.

As a further technical scheme, one end of the through hole is provided with a process hole, and the diameter of the process hole is larger than that of the through hole. Therefore, the reaming depth of the through hole can be reduced, the risk of fracture of the reaming drill is reduced, and the manufacturing cost is reduced.

As a further technical scheme, the process hole is located at one end, facing the inner side face of the crescent main plate, of the through hole, and the diameter of the process hole is larger than the thickness of the tooth top of the driving gear. Therefore, the driving gear tooth top can be effectively prevented from being dug in the through hole when passing through the through hole, and the smoothness of oil in the through hole is ensured.

Has the advantages that: because in the crescent moon mainboard, set up the perforating hole between the lateral surface, and the perforating hole is in the crescent moon mainboard, opening on the lateral surface just is located the crescent moon mainboard, on the balance point of lateral surface, make in the crescent moon mainboard through the suitable flow of perforating hole again simultaneously, effective sealing between crescent moon mainboard medial surface and the driving gear tooth top can be guaranteed just to the pressure differential between the lateral surface, can not produce too big pressure, be favorable to delaying the even wear and the deformation of sealing rod of crescent moon mainboard medial surface so by a relatively large margin, thereby effectively prolong crescent gear pump's life.

Drawings

FIG. 1 is a schematic diagram of one configuration of the present invention.

Fig. 2 is an enlarged schematic view of the R portion in fig. 1.

Fig. 3 is an enlarged schematic view of the M portion in fig. 2.

Fig. 4 is a schematic structural diagram of the crescent main plate in the invention.

In the figure: the pump body 1, the ring gear 2, the low-pressure hydraulic area 3, the locating rod 4, the crescent auxiliary plate 5, the crescent main plate 6, the high-pressure hydraulic area 7, the driving gear 8, the pin shaft 9, the through hole 10, the outer sealing area 11, the inner sealing area 12, the round bulge 13, the sealing rod 14, the spring piece 15 and the fabrication hole 16.

Detailed Description

The invention is further illustrated by the following specific examples in conjunction with the accompanying drawings.

Example (b): an internal gear pump is shown in the figure, and comprises a hollow pump body 1, wherein a rotatable annular inner gear ring 2 is arranged in a pump cavity of the pump body 1, a driving gear 8 meshed with the inner gear ring 2 is arranged in the inner gear ring 2, the outer diameter of the driving gear 8 is smaller than the inner diameter of the inner gear ring 2, the axial center of the inner gear ring 2 is offset relative to the axial center of the driving gear 8, a positioning rod 4 fixedly connected with the pump body 1 is arranged on the outer side of the meshing side of the driving gear 8 and the inner gear ring 2, a floating sealing device is arranged between the meshing side and the positioning rod 4, the sealing device divides a cavity in the pump body 1 into a high-pressure hydraulic area 7 and a low-pressure hydraulic area 3, the high-pressure hydraulic area 7 is positioned on one side of the sealing device facing the meshing side of the driving gear 8 and the inner gear ring 2, and the other side of the sealing device opposite to the low-pressure hydraulic area 3, the sealing device comprises a crescent mainboard 6 and a crescent auxiliary plate 5, one end of the crescent mainboard 6 close to the positioning rod 4 is pivoted on the pump body 1 through a pin shaft 9, one end of the crescent auxiliary plate 5 is abutted against the positioning rod 4, the inner side surface of the crescent mainboard 6 close to the driving gear 8 is in arc-shaped adaptation with the outer peripheral surface of the driving gear 8, a plurality of inner sealing areas 12 are formed between the tooth space of the driving gear 8 and the inner side surface of the crescent mainboard 6, the outer side surface of the crescent auxiliary plate 5 far away from the crescent mainboard 6 is in arc-shaped adaptation with the inner peripheral surface of the inner gear ring 2, a plurality of elastic sealing mechanisms are arranged between the outer side surface of the crescent mainboard 6 close to the crescent auxiliary plate 5 and the inner side surface of the crescent auxiliary plate 5 close to the crescent mainboard 6, the elastic sealing mechanisms separate the gap between the crescent mainboard 6 and the crescent auxiliary plate 5 into a plurality of outer sealing areas 11, the elastic sealing mechanism is composed of a sealing rod 14 and a spring piece 15, 3 through holes 10 are arranged between the inner side surface and the outer side surface of the crescent mainboard 6, the 3 through holes 10 are arranged at equal intervals, wherein the through hole 10 arranged in the middle is positioned in the middle of the width of the crescent mainboard 6, the position of the through hole 10 on the inner side surface of the crescent mainboard 6 is two-fifths of the ratio of the arc length of the inner side surface of the crescent mainboard 6 close to one end of the positioning rod 4 to the total arc length of the inner side surface of the crescent mainboard 6, the included angle between the axial center line of the through hole 10 and the normal line of the through hole 10 on the position of the inner side surface of the crescent mainboard 6 is 24.68 degrees, the axial center line of the through hole 10 inclines towards one side of the positioning rod 4 relative to the normal line, and the diameter of the through hole 10 is 0.52 mm; one end of the through hole 10 facing the inner side face of the crescent main plate 6 is provided with a process hole 16, and the diameter of the process hole 16 is larger than the thickness of the tooth top of the driving gear 8; in order to effectively increase the contact area between the sealing rod 14 and the crescent mainboard 6, thereby improving the contact stress of the sealing rod 14, prolonging the service life of the sealing rod 14 and ensuring the sealing effectiveness of the external sealing area 11 of the crescent mainboard 6, the external sealing area 11 of the crescent mainboard 6 is provided with a round bulge 13 lifted outwards at the position of the sealing rod 14.

The above-described embodiment is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.

Details not described in the present specification belong to the prior art known to those skilled in the art.