JPH0742446U - Gear pump - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a gear pump in which the clearance of the side surface of the gear is minimized to prevent leakage of the pump transfer liquid and the pump performance can be maintained with a simpler structure. thing. A flexible plate member (35) is inserted between one side of a gear casing (6) placed inside a pump body (1) and a corresponding side surface of a rear bearing casing (8). The discharge pressure is applied to the member as a back pressure through the back pressure applying hole (36) formed in the rear bearing casing during the pump operation. As a result, the flexible plate member is elastically deformed and pressed against the side surfaces of the gear casing and the gears (9, 10), the side surface clearance of the gear is covered to the minimum state, and the leakage of the pump transfer liquid is prevented. The stable pump performance is maintained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a gear pump that includes a drive gear, a driven gear that meshes with the drive gear, and a gear casing that houses these gears.

[0002]

[Prior art]

 In this type of gear pump, a front bearing casing and a rear bearing casing that rotatably support a drive gear and a driven gear are provided on both sides of the gear casing, and the side faces of these bearing casings correspond to the side faces of the gear casing, respectively. As a result, the partition walls on both sides of the storage unit that stores the drive gear and the driven gear are configured. If the gap between the partition wall and the side surface of the gear, that is, the side surface gap of the gear, is too wide, the pump performance is deteriorated because the leakage of the pump transfer liquid increases. On the other hand, when the partition wall is in excessive contact with the gear side surface and there is no side surface skimmer, the partition wall itself is a rigid surface, which increases frictional resistance and increases the rotational load and noise of the gear during pump operation. There is a big problem. In other words, this side clearance greatly affects the pump performance and the pump operating condition.

In the conventional gear pump, the related parts including the gear and the gear casing are precisely processed to maintain the side clearance of the gear in an optimum state as much as possible. However, if sufficient pump performance is not obtained after assembly, parts are replaced, and parts are sorted and assembled.

[0004]

[Problems to be solved by the device]

 Therefore, in conventional gear pumps, gears, gear casings, and other related parts are manufactured with extremely strict tolerances of a few microns in order to obtain sufficient pump performance and to set the optimum side clearance to minimize rotational load and noise. It was necessary to increase the production cost and the assembly cost. In addition, after the assembly, if the gear side wears and the side gap spreads due to the pump operation, pump leakage will be large and pump performance will deteriorate, but pump performance will be restored except by replacing the related parts. There was no countermeasure to do so, and the replacement work required time and money.

Therefore, the present invention has been made in view of the above problems in the conventional gear pump, and the purpose thereof is to always maintain the side clearance of the gear in a stable state without liquid leakage to obtain sufficient pump performance. At the same time, there is a need to provide a gear pump that does not require strict tolerances in the manufacture of parts and can reduce manufacturing and assembly costs.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a pump body having a suction port and a discharge port in a pump head, a drive gear and a driven gear that are rotatably opposed to the pump body and meshed with each other. A rotary drive means for applying a rotary drive force to the drive gear, a gear casing arranged in the pump body, and the drive case formed in the gear casing in a state of being opened to a side surface side of the gear casing. A storage part for storing a gear and a driven gear, a suction side port and a discharge side port communicating with the suction port and the discharge port, respectively, and a drive gear and a driven gear which are arranged on both sides of the gear casing with the gear casing interposed therebetween. Each of them has a bearing casing rotatably supported, and by mutual rotation of the drive gear and a driven gear driven by the same, the suction port is moved from the suction port to the suction side port. Based on the structure of a gear pump configured to transfer the entered pump transfer liquid to the discharge port through the discharge side port, the pump was inserted between the gear casing and at least one bearing casing of the bearing casing. The flexible plate member communicates with the discharge side port and guides the discharge pressure of the pump transfer liquid at the discharge side port to the flexible plate member as a back pressure from a side opposite to the gear casing. Pressure introducing passage means, and the back pressure applied to the flexible plate member by the back pressure introducing passage means presses the flexible plate member toward a side surface of the corresponding gear casing to thereby form a side surface of the gear. We propose a gear pump configured to cover the clearance.

[0007]

In the gear pump of the present invention having the above-described structure, in order to always keep the side clearance of the gear to a minimum and to suppress the rotational load and the increase in noise due to excessive friction in the contact with the gear, the gear casing A flexible plate member is inserted between the bearing casing and the bearing casing, and a discharge pressure is applied as a back pressure from the discharge side port to the plate member by the back pressure introducing passage means and pressed toward the side surface of the gear casing. It is configured to. Therefore, since the flexible plate member is elastically deformed and positioned so as to be in constant contact with the side surface of the gear by receiving the rear surface, the side surface skimmer is covered by the minimum and substantially zero state, and the leakage of the pump transfer liquid is prevented. Is prevented. Moreover, since the contact with the gear side surface is an elastic contact with the discharge pressure as the back pressure, excessive friction is not generated, and rotational load and noise are not increased. Furthermore, as the discharge pressure increases, the liquid leakage from the side gap generally increases, but in the case of the present invention, the back pressure rises as the discharge pressure rises, so the side gap is always kept in a stable minimum state. To be done.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a pump main body, a motor frame 2 in which a drive motor (not shown) is arranged, and a cylindrical outer side which is attached via a mounting plate 3 to a front end portion along an axis XX thereof. It is composed of a bracket 4 and a pump head 5 attached to the front end of the bracket.

Reference numeral 6 denotes a gear casing arranged on the pump body 1 inside the outer bracket 4, and reference numerals 7 and 8 respectively correspond to front and rear sides or both sides of the gear casing 6 along the axis XX. A bearing casing and a rear bearing casing, 9 and 10 are a drive gear housed in a housing portion 6a of the gear casing 6 and a driven gear meshed with the drive gear, and 11 and 12 are mutually along the axis X-X direction. The drive gear shaft and the driven gear shaft extend in parallel and are coupled to the drive gear 9 and the driven gear 10 by a key to rotate integrally. The storage portion 6a is formed in such a manner that both side surfaces of the gear casing 6 are open.

Both gear shafts 11 and 12 are rotatably supported by a front bearing casing 7 and a rear bearing casing 8 via a bearing sleeve 13, and one end of the drive gear shaft 11 further extends. At its extended end, a driven rotor 15 having a driven magnet 14 and a key 16 are integrally rotatably connected. Reference numeral 17 denotes a drive rotating body which is arranged to face the driven rotating body 15 via a bottomed cylindrical rear casing 18 and is directly connected to a motor shaft 19 of a drive motor (not shown). A drive magnet 20 forming a coupling is provided.

When the drive rotor 17 is rotated by the rotation of the drive motor, the driven rotor 15 is rotated by the magnet coupling so that the drive gear 9 is rotated integrally with the drive gear shaft 11. As a result, the driven gear 10 also rotates integrally with the driven gear shaft 12. As described above, a series of drive transmission systems constitutes a rotary drive means for applying a rotary drive force to the drive gear 9.

The rear casing 18 is liquid-tightly fitted to the outer peripheral surface of the front bearing casing 7 via the seal ring 21 at the front end side opening end, and only the inner region is filled with the pump transfer liquid, so that the casing is The outer region of 18, for example the rotary drive 17 and the part of the motor shaft 19 is isolated from the pumped liquid.

Reference numeral 22 denotes a coil spring which is interposed between the rear casing 18 and the rear bearing casing 8 and serves as a biasing means. The coil spring 22 has an axis line X-X so as to constantly push the rear bearing casing 8 toward the gear casing 6. The gear casing 6 is held in a clamped state in cooperation with the front bearing casing 7 by being biased in the direction.

The outer bracket 4 is fixed to the motor frame 2 together with the mounting plate 3 by mounting screws 23, and the bracket 4 and the mounting plate 3 are fixed to each other by mounting screws 24. On the other hand, the pump head 5 is integrally attached and fixed to the front bearing casing 7 with the gasket 26 (FIG. 1) sandwiched by the long attachment screw 25 shown in FIG.

As shown in FIG. 2B, the pump head 5 has a suction port 27 and a discharge port 28 on the side, which are located along the axis XX and are located in the pump head 5 and the front bearing casing 7. 2 (a) and 2 (b) formed in FIG. 2 communicate with respective end portions of the suction side communication hole 29 and the discharge side communication hole 30. The other end of each of the communication holes 29, 30 communicates with the suction side port 31 and the discharge side port 32 shown in FIGS. 2 (d) and 3, respectively. These ports 31 and 32 are formed on both sides of the storage portion 6a of the gear casing 6 that stores the drive gear 9 and the driven gear 10.

Therefore, in each figure, both gears 9 and 10 are shown in FIG. 2 (d) as indicated by the solid arrow on the suction side and the dashed arrow on the discharge side. When rotating in the direction of the arrow, the pump transfer liquid flowing in through the suction port 27 enters the suction side port 31 through the suction side communication hole 29. Here, as the gears 9 and 10 rotate, the pump transfer liquid is sent between the gears 9 and 10 and the inner peripheral wall of the housing portion 6a and is sent to the discharge side port 32. Here, the pump transfer liquid joins and is pumped from the discharge port 28 to the supply site (not shown) through the discharge side communication hole 30.

Reference numeral 35 denotes a flexible plate member interposed between the gear casing 6 and the rear bearing casing 8 and formed of a plastic sheet or a thin plate, and has a disc shape having a diameter substantially equal to the inner diameter of the rear casing 18. Is doing. Reference numeral 36 is a back pressure applying hole for applying a back pressure to the flexible plate member 35 from the side opposite to the gear casing 6, and as shown in FIG. Is formed so as to penetrate therethrough, one end of which is opened to the back side of the flexible plate member 35 and the other end of which is opened to the rear space 18a of the rear casing 18 in which the driven rotor 15 is housed. In parallel with the back pressure applying hole 36, the rear bearing casing 8 is also provided with a discharge pressure take-out hole 37 which is similarly formed through. As shown in FIGS. 2 (c) and 3, one end thereof opens at the side corresponding to the gear casing 6, and in the assembled state, the discharge side port 32 has an opening 35a (FIG. 3) formed in the flexible plate member 35. ) Through the communication. The other end of the discharge pressure outlet 37 is open to the rear space 18a of the rear casing 18.

As shown in FIGS. 2C and 3, a recess 8 a is formed on the side surface of the rear bearing casing 8 corresponding to the gear casing 6. The recess 8a corresponds to the side surface shape of the storage portion 6a of the gear casing 6, and the back pressure applying hole 36 is opened in the recess 8a.

As shown in FIG. 3, the flexible plate member 35 has insertion holes 35b and 35c for the drive gear shaft 11 and the driven gear shaft 12 in addition to the opening 35a. Further, a pair of left and right guide openings 35d are formed in the flexible plate member 35, and a pair of round bars that integrally project from the side surface of the rear bearing casing 8 in the assembled state are formed in these openings 35d. The guide member 38 is inserted. The guide member 38 is fitted into a guide hole 6b formed corresponding to the gear casing 6, and the tip end thereof is inserted into a support hole 7a formed in the front bearing casing 7 as shown by a broken line in FIG. 2 (a). Has been. Therefore, the rear bearing casing 8 and the gear casing 6 are supported by the guide member 38 such that the rear bearing casing 8 and the gear casing 6 are movable only in the axis XX direction with respect to the front bearing casing 6. The gear casing 6 is constantly urged by the coil spring 22 from the rear bearing casing 8 along the axis XX toward the front bearing casing 7, and is sandwiched between the two bearing casings 7, 8.

During pump operation, part of the pump transfer liquid that has flowed out to the discharge side port 32 is guided to the rear space 18 a through the discharge pressure extraction hole 37 and fills this area to surround the driven rotor 15. Affected by. Then, as shown by the arrow in FIG. 1, the pressure is applied from the rear space 18a to the flexible plate member 35 through the back pressure applying hole 36 from one end opening of the hole. That is, the discharge pressure is applied as a back pressure, whereby the flexible plate member 35 is elastically deformed to come into contact with the corresponding side surface of the gear casing 6 and the corresponding side surfaces of the gears 9 and 10 in the storage portion 6a. Maintained. Therefore, the lateral clearance of these gears 9 and 10 is covered with a minimum clearance of substantially zero. A series of flow passages including the back pressure applying hole 36 and the discharge pressure take-out hole 37 constitute a back pressure introducing passage means for guiding the discharge pressure to the flexible plate member 35 as a back pressure.

Since the pump transfer liquid flowing out from one end opening of the back pressure applying hole 36 toward the flexible plate member 35 spreads in the recess 8 a, the side surface region of the flexible plate member 35, particularly the side surface region of the storage portion 6 a. A uniform back pressure is applied to the entire surface, not locally. Therefore, the side surface clearance of the gear is more surely covered in the minimum clearance state.

During the operation of the pump, the back pressure is constantly applied to the flexible plate member 35 as described above, and the leakage of the pump transfer liquid from the side surface skimmer of the gear is prevented. Moreover, in general, the higher the discharge pressure is, the more the liquid leaks from the side surface skimmer, but according to the configuration of the present invention, since the discharge pressure is introduced as the back pressure, the back pressure rises according to the discharge pressure. Therefore, regardless of the discharge pressure, it is possible to prevent liquid leakage in a stable state at all times. Further, since the flexible plate member 35 comes into contact with the side surfaces of the gears 9 and 10 by the action of back pressure by elastic deformation, unlike the contact with the wall surface of the rigid body, it does not cause excessive friction. Since it can be flexibly deformed by the resistance received from the side of the gear, the rotational load and noise of the gear will not increase excessively.

Although the flexible plate member 35 is interposed between the gear casing and one bearing casing, that is, the rear bearing casing 8 in the above embodiment, the other front bearing casing 7 is disclosed. It may be placed between and. Further, in the embodiment, the configuration in which the magnetic coupling is used as the rotation drive means is disclosed, but the present invention can be similarly applied to the configuration in which the motor shaft 19 is directly connected to the drive gear shaft 11.

[0024]

[Effect of device]

 As described above, according to the gear pump of the present invention, the flexible plate member is inserted between the gear casing and the bearing casing, and the back pressure introducing passage means is provided to the plate member so as to prevent the flexible plate member from the discharge side port. Since the discharge pressure is applied as a back pressure, the plate member is elastically deformed and pressed toward the corresponding side surface of the gear casing and the side surface of the gear, thereby covering the side surface gap of the gear. Liquid leakage is prevented and stable pump performance can always be maintained. Therefore, strict tolerances are not required in the production of parts, the production and assembly costs can be reduced, and even if the gear side surface is worn by the pump operation, the flexible plate member can flexibly cope with elastic deformation. Therefore, sufficient pump performance can be exhibited for a long time without replacing parts. Further, even when the parts need to be replaced, it is often necessary to replace only the flexible plate member, which is advantageous in terms of replacement work and cost. Furthermore, since the flexible plate member elastically contacts the gear side face with the discharge pressure as the back pressure, unlike the conventional contact with the rigid wall surface, excessive friction is not generated, and rotation load and noise are not generated. Does not increase. Furthermore, the higher the discharge pressure, the more the liquid leakage from the side skimmer tends to increase. However, since the discharge pressure is used as the back pressure in the present invention, the back pressure increases as the discharge pressure increases, and the flexibility increases. Since the pressing force of the plate member becomes stronger, the side surface clearance is always covered in a stable state, so that various practical effects can be obtained.

[Brief description of drawings]

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

2 (a), (b), (c), and (d) are cross-sectional views taken along lines AA, BB, CC, and DD of FIG. 1, respectively. It is a figure.

FIG. 3 is an exploded perspective view of a main part of the gear pump shown in FIG.

[Explanation of symbols]

 1 Pump Main Body 6 Gear Casing 7 Front Bearing Casing 8 Rear Bearing Casing 9 Drive Gear 10 Driven Gear 32 Discharge Side Port 35 Flexible Plate Member 36 Back Pressure Applying Hole 37 Discharge Pressure Extraction Hole

Claims (1)

[Scope of utility model registration request] 1. A pump body having a suction port and a discharge port formed in a pump head, a drive gear and a driven gear which are rotatably opposed to the pump body and meshed with each other, and rotationally driven by the drive gear. A rotary drive means for applying a force, a gear casing arranged in the pump body,
An accommodating portion formed in the gear casing in an aspect opened to a side surface side of the gear casing and accommodating the drive gear and the driven gear, a suction side port and a discharge side port communicating with the suction port and the discharge port, respectively, A bearing casing, which is arranged on both sides of the gear casing in a corresponding manner and rotatably supports the drive gear and the driven gear, respectively. In a gear pump configured to transfer the pump transfer liquid that has flowed into the port to the discharge port through the discharge side port, a flexibility inserted between the gear casing and at least one bearing casing of the bearing casings. The discharge pressure of the pump transfer liquid at the discharge side port communicates with the plate member and the discharge side port, and is flexible. Back pressure introducing passage means for guiding the plate member as a back pressure from a side opposite to the gear casing, and the flexibility is provided by the back pressure applied to the flexible plate member by the back pressure introducing passage means. A gear pump, characterized in that a plate member is pressed toward a side surface of a corresponding gear casing so as to cover a side surface clearance of the gear.