JPH0647686U - Gear pump offset prevention structure - Google Patents

Abstract

(57) [Summary] [Object] In a gear pump for pressure-feeding a viscous fluid, the gears 26, 27 in the pump chamber 28 are prevented from shifting to one side to prevent seizure and wear and maintain smooth rotation. A pair of gears 26 and 27 are housed in a pump chamber 28 formed in a casing 25, and a pair of side plates 23 sandwiching the casing 25 and the gears 26 and 27,
Grooves 55, 56 extending in the circumferential direction on the inner surfaces 46, 47 of 24
Is formed to guide the high-pressure viscous fluid to the outflow port 60, and the pressure prevents the gears 26 and 27 from being offset.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure for preventing deviation of gears of a gear pump used for quantitatively transferring and boosting a viscous fluid such as polyester and nylon.

[0002]

[Prior art]

 FIG. 5 is a simplified cross-sectional view showing a typical prior art gear pump 1. A casing 5 sandwiched by the two side plates 3 and 4 is formed with a pump chamber 8 in which a pair of gears 6 and 7 meshing with each other are housed, and shafts 9 and 10 are fixed to the gears 6 and 7, respectively. It The power from a motor (not shown) is decelerated and transmitted to the one shaft 9 by a speed reducer, whereby the gears 6 and 7 are rotationally driven in the directions of arrows A1 and A2, respectively. An inlet side space 13 to which a viscous fluid such as polyester or nylon is supplied from an extruder or the like is formed on the downstream side of the meshing portion 11 of the gears 6 and 7 of the casing 5 in the rotational directions A1 and A2. An outlet space (not shown) is formed on the side opposite to the inlet space 13 with respect to the meshing portion 11. The viscous fluid supplied from the inlet space 13 is transferred to the downstream side of the gears 6 and 7 in the arrow A1 and A2 directions while being fitted in the tooth spaces of the gears 6 and 7, It is pushed out from the tooth space by the meshing of the teeth and discharged from the outlet side space.

[0003]

[Problems to be solved by the device]

 In such a prior art, since the gears 6 and 7 and the shafts 9 and 10 are not restrained against the displacement in the axial direction thereof, the gears 6 and 7 are deviated in either axial direction. In this case, the side surfaces 6a 1, 6b; 7a, 7b of the gears 6, 7 come into contact with the inner surfaces 3a, 4a of the one side plate 3 or 4 due to such deviation, and the gap S1 or S2 becomes zero. . When the gap S1 or S2 becomes zero in this way, a large frictional force acts on each gear 6, 6 due to the sliding contact with the side plate 3 or 4, and smooth rotation of each gear 6, 7 is impeded. .

Therefore, an object of the present invention is to provide a structure for preventing deviation of a gear pump, which prevents deviation of the gear in the axial direction, achieves a lubricated state, and maintains smooth rotation. That is.

[0005]

[Means for Solving the Problems]

 According to the present invention, a pump chamber accommodating a plurality of gears meshing with each other is formed in a casing sandwiched by two side plates, and the shaft of each gear is axially displaceable by the two side plates and is rotatable about the axis. Each side plate is rotatably supported on each inner surface of the side plate, which faces both side surfaces of the gear, and is formed with a groove extending in the circumferential direction that communicates with the outlet space on the upstream side in the rotation direction of the meshing portion of each gear. The groove is divided at predetermined intervals in the circumferential direction in the vicinity of the inlet space on the downstream side of the meshing portion in the rotational direction, and is a structure for preventing deviation of the gear pump. .

[0006]

[Action]

 According to the present invention, a concave groove is formed in two side plates that sandwich a casing accommodating a plurality of gears from both sides, and the concave groove is communicated with the outlet space and extruded from the meshing portion of each gear. Guide high-pressure viscous fluid. As a result, the gears are arranged in the neutral position in the axial direction by the pressure of the viscous fluid in the concave groove, and it is possible to prevent the contact with the inner surface of the side plate. In this way, since each gear does not come into contact with the inner surface of the side plate, there is no fear that the rotation of each gear will be hindered, and reliable lubrication can be realized.

[0007]

【Example】

 1 is a sectional view showing a gear pump 21 according to an embodiment of the present invention, and FIG. 2 is a perspective view of the gear pump 21. A casing 25 sandwiched by the two side plates 23 and 24 has a pump chamber 28 in which two gears 26 and 27 are accommodated. A shaft 29 is inserted into the one gear 26, and a key 30 integrally formed with the gear 26 is fitted therein, and rotation about the axis is transmitted in a state in which the key 30 can be displaced in the axial direction. Power from a motor (not shown) is decelerated and transmitted to the shaft 29 by a speed reducer, and is rotationally driven together with the gear 26 in the arrow B1 direction.

By the rotation of the gear 26 as described above, the other gear 27 meshed in the meshing portion 31 is rotationally driven in the arrow B2 direction. A shaft 33 is inserted through the gear 27, and both axial end portions of the shaft 33 are press-fitted into one of shaft holes 34 and 35 formed in the side plates 23 and 24 and are supported in the other, respectively. The gear 27 rotates with respect to it. Sealing members 36 and 37 are attached to both ends of the shaft 29 in the axial direction, and are supported in the rotating direction by bolts 38 and 39. The seal members 36 and 37 are covered with pressing members 41 and 43 in the sleeves 61 and 63, and are retained by being pressed against the side plates 23 and 24 by bolts 44 and 45, respectively. The casing 25 and the side plates 23, 24 are fixed to each other by a plurality of bolts 40.

The inner surfaces 46, 47 of the side plates 23, 24 facing each other and the side surfaces 48, 49; 50, 51 of the gears 26, 27 are spaced apart from each other with intervals S10, S20. These intervals S10 and S20 are, for example, about 35 μm. The viscous fluid to be pumped flows into the spaces S10 and S20 to achieve lubrication, and the viscous fluid also flows into the shaft holes 53 and 54 through the spaces S10 and S20 to achieve lubrication. is doing. The viscous fluid is a highly viscous fluid such as polypropylene, polyethylene, polycarbonate, polystyrene, nylon, polyester, ABS resin, methacrylic resin, polyurethane and PEEK, and their viscosity ρ is about 100,000 poise at maximum. The shaft 29 is driven to rotate at 10 to 50 rpm and discharges the viscous fluid at 0.1 to 40 l / min.

FIG. 3 is a front view of the side plate 24 as viewed from the left side of FIG. 1, and FIG. 4 is a perspective view of the side plate 24. Like the side plate 24 described above, the side plate 23 is symmetrically configured with the casing 25 being sandwiched between the side plates 23 and 24, and one side plate 24 will be described while avoiding duplication. The inner surface 47 of the side plate 24 is formed with a groove 55 that surrounds the shaft hole 34 and extends in the circumferential direction, and a groove 56 that surrounds the shaft hole 35 and extends in the circumferential direction. The outer inner peripheral surfaces 55a and 56a of the recessed grooves 55 and 56 are formed more radially inward than the troughs of the teeth of the toothed wheels 26 and 27 to reduce the pressure force in the recessed grooves 55 and 56. To prevent. The lands 57 and 58, which are continuous with the inner surface 47 in the same plane, are formed radially inward of the concave grooves 55 and 56. Further, in the casing 25, an inflow port 59 that forms an inlet space downstream of the meshing portion 31 in the rotational direction B1, B2 of the gears 26 and 27 and the gears 26 and 27 from the meshing portion 31 are provided. An outlet 60 that forms an outlet space is formed on the upstream side in the rotation directions B1 and B2. At the inlet 59, 50 to 100 kgf / cm discharged from an extruder (not shown) or the like. ² A viscous fluid having a certain pressure is supplied, and the viscous fluid is stored between the tooth groove of each gear and the inner peripheral surface of the pump chamber 28 by the rotation operation of each gear 26, 27. The gears 26 and 27 are transferred in the rotational directions B1 and B2 and discharged from the outlet 60.

The reason for providing such recessed grooves 55, 56 is that the gears 26, 27 are operated in a biased manner in the initial assembled state or due to changes in operating conditions, and the intervals are S20 >> S10. At this time, on the S1 side, the shearing force applied to the viscous fluid that has entered this portion becomes larger than on the S20 side, the viscosity of the liquid on the S10 side decreases, and galling due to surface contact tends to occur on the S1 side. At this time, since the concave grooves 55 and 56 are provided, the pressure of the concave groove 56 on the S10 side is higher than the pressure of the concave groove 55 in S20 (PS ₁₀ > PS ₂₀ ) due to the narrow gap of S10. If the interval S20 Hirogare, each dividing portion 64a, 64 b liquid pressure PS ₂₀ step S20 side flows through the guide groove 66 and 67 by short path is reduced. Therefore, the gears 26 and 27 are pushed back to the right in FIG. If the pushing-back force becomes too great and S20 << S10, the above-mentioned reverse operation works on each gear 26, 27. That is, when the gears 26, 27 come close to each other so that they may come into contact with each other in one direction so that they may bite each other, a repulsive force is generated, and a further repulsive force does not allow the approach.

The inner surface 47 of the side plate 24 also divides the recessed grooves 55, 56 in the circumferential direction, and divides the lands 57, 58 and the inner surface 47 in the same plane as divided portions 64a, 64b; 65a, 65b. Is formed. Between the divided portions 64a, 64b; 65a, 65b, the viscous fluid that has flowed into the gap S20 between the side surfaces 49, 51 of the gears 26, 27 and the inner surface 47 is provided with the inner peripheral surface of the shaft hole 54 and the outer peripheral surface of the shaft 29. The guide groove 66 is formed between the outer peripheral surface of the shaft 33 and the inner peripheral surface of the gear 27, and the guide groove 67 is formed between the outer peripheral surface of the shaft 33 and the inner peripheral surface of the gear 27.

In the vicinity of the outlet 60 of the side plate 24, a storage chamber 68 is formed facing the outlet 60 to guide the viscous fluid, and the high-pressure viscous fluid in the storage chamber 68 functions as a so-called throttle. It is guided to the concave grooves 55 and 56 via the communication grooves 69 and 70. By appropriately adjusting the lengths L1 and L2 of the communication grooves 69 and 70, the supply amount of the high-pressure viscous fluid introduced into the concave grooves 55 and 56 can be adjusted.

Regarding the other side plate 23, a repulsive force is applied to each gear 26, 27 by each groove formed symmetrically with the above-mentioned groove 55, 56, and each gear 26, 27 is moved. Can be kept in a neutral position.

[0015]

[Effect of device]

 As described above, according to the present invention, since the groove is formed on the inner surface of each side wall, the gear that guides the viscous fluid in the outlet space, which has a high pressure, and has a small gap with the side plate is added from the side. It is possible to press the gears and prevent each gear from being biased in the pump chamber. As a result, it is possible to reliably prevent the gears from coming into contact with the side wall, prevent seizure and wear from occurring, and smoothly rotate the gears.

[Brief description of drawings]

FIG. 1 is a sectional view showing a gear pump 21 according to an embodiment of the present invention.

FIG. 2 is a perspective view of the gear pump 21 shown in FIG.

FIG. 3 is a front view of the side plate 24 as viewed from the left side of FIG.

FIG. 4 is a perspective view of a side plate 24.

FIG. 5 is a simplified cross-sectional view of a typical prior art.

[Explanation of symbols]

 21 gear pump 23, 24 side plate 25 casing 26, 27 gear 28 pump chamber 29, 33 shaft 31 meshing portion 34, 35; 53, 54 shaft hole 46, 47 inner surface 48, 49, 50, 51 side surface 55, 56 concave groove 59 Inflow port 60 Outflow port 64a, 64b; 65a, 65b Divided part 66, 67 Guide groove 68 Storage chamber 69, 70 Communication groove

Claims (1)

[Scope of utility model registration request] 1. A pump chamber, in which a plurality of gears meshing with each other are accommodated, is formed in a casing sandwiched by two side plates, and the shafts of the gears are axially displaceable by the two side plates and rotate about the axis. Each side plate is rotatably supported on each inner surface of the side plate, which faces both side surfaces of the gear, and is formed with a recessed groove extending in the circumferential direction and communicating with the outlet space on the upstream side in the rotation direction of the meshing portion of each gear. The concave groove is divided at predetermined intervals in the circumferential direction in the vicinity of the inlet space on the downstream side in the rotation direction with respect to the meshing portion, and the deviation preventing structure of the gear pump is characterized.