JP2510241B2 - Gear pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gear pump suitable for use in a case where a liquid in a tank is divided into a plurality of discharge amounts and is pressure-fed at the discharge side.

(Prior Art) When the liquid in one tank is pressure-fed by a pump with its discharge side divided into two parts, conventionally, as shown in FIG. The outlets b and c are provided, and the inlets f and g of the two gear pumps d and e are connected to the outlets b and c, respectively. The discharge amount was divided into two. Alternatively, as shown in FIG. 5, one take-out port b'is provided in the tank a ', and one gear pump d'is provided at this take-out port b'.
Of the gear pump d'is connected to a bifurcated distributor j, and the distributor j divides the liquid discharge amount into two. Was doing.
Further, as shown in FIG. 6, a tank a ″ is provided with one outlet b ″, and one inlet l of one screw pump k is connected to this outlet b ″, and at the same time, this screw pump is connected. Two discharge ports m and n were provided in k, and the discharge amount of the liquid was divided into two by these discharge ports m and n, where p is a screw shaft and q is a core. It is a motor that rotates the screw shaft p.

(Problems to be Solved by the Invention) In the structure shown in FIG. 4, although the discharge amount division accuracy is high, the two gear pumps d and e and the drive thereof corresponding to these gear pumps d and e are performed. Since it requires two machines (motors, etc.), it cannot be applied when the cost is high and the installation space is small.

Further, in the one shown in FIG. 5, depending on the shape of the passage of the distributor j and the load pressure (pressure loss due to pipe resistance),
A large difference occurs in the liquid flow rate of each of the two divided paths, and, for example, the accuracy of the synthetic resin product varies.

Further, in the one shown in FIG. 6, since it is difficult to generate a large pressure with the screw pump k, when the discharge amount is divided into two at the discharge ports m and n, the accuracy of dividing the discharge amount is poor. Become.

The present invention has been made in view of the above circumstances, and it is possible to accurately divide a discharge amount into a plurality of discharge amounts on the discharge side, but a small installation space is required and cost reduction can be smoothly achieved. The purpose of the present invention is to provide a gear pump.

(Means for Solving the Problems) In order to achieve the above object, the present invention is a gear pump that pushes fluid from a suction side to a discharge side by two or more gears that mesh with each other in a casing. And at least two discharge ports, the same number of sets of gears that mesh with the discharge ports, and intermediate bearings that are located between the gears and that respectively support a drive shaft and a driven shaft of the gears. The intermediate bearing is configured to be movable in a predetermined range in the axial direction with respect to the drive shaft and the driven shaft.

(Operation) The fluid sucked into the casing from one suction port is divided in the casing, pushed out by the plurality of liquid feed gear pairs, and discharged from the same number of discharge ports facing the respective gears. If there is a difference in the discharge pressure of the fluid from each discharge port, this difference in discharge pressure will occur on both sides of the intermediate bearing. Since the intermediate bearing is configured to be movable in the axial direction, it is pushed from the high discharge pressure side to the low discharge side and moves along the shaft, and the gap between the gear and the intermediate bearing is wide on the high discharge pressure side. The leak amount of the liquid from the gap increases, and on the contrary, the gap becomes narrower and the leak amount decreases on the side where the discharge pressure is low. As a result, the discharge pressure from each discharge port is automatically equalized.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In the drawings, reference numeral 1 denotes a casing. The casing 1 has a substantially cylindrical main body 2 having both open end surfaces, a front cover 4 liquid-tightly attached to a front end surface of the main body 2 with a bolt 3, and a rear portion of the main body 2. The rear cover 6 is liquid-tightly attached to the end surface with bolts 5. One suction port 7 on the upper surface of the main body 2
However, a plurality of, for example, two discharge ports 8 and 9 are provided on the lower side surface, and these discharge ports 8 and 9 are separated from each other in the axial direction of the main body 2. The opening area of the suction port 7 is set larger than that of the discharge ports 8 and 9. The inner end surface of the suction port 7 has a number corresponding to the number of discharge ports provided by the distribution wall 10.
That is, it is divided into two distribution paths 11 and 12. Each of these distribution paths 11 and 12 faces the discharge ports 8 and 9, respectively. The distribution wall is formed as part of the casing.

A pair of shafts (driving shaft and driven shaft) 13 and 14 are rotatably disposed in the main body 2 along the axial direction thereof and in parallel with each other with a space therebetween. The drive shaft 13 includes end bearings 15 and 16 fixed to inner surfaces of both ends of the main body 2 and these end bearings 1.
5 and 16 are rotatably supported by an intermediate portion bearing 17 which is located between 5 and 16 and is movable in the axial direction. The driven shaft 14 includes end bearings 18 and 19 fixed to the inner surfaces of both ends of the main body 2, and an intermediate portion that is located between the end bearings 18 and 19 and is movable in the axial direction. The shaft 20 and the shaft 20 are rotatably supported. This intermediate bearing
20 is held on the distribution wall 10.

A pair of gears 21, 22 are fitted to the drive shaft 13 between the bearings 15, 16 at both ends thereof and the intermediate shaft 17 so as to be integrally rotatable. These gears 21, 22 are key 23,
The rotation of the drive shaft 13 is stopped by 24.

Further, a pair of gears 25, 26 is fitted to the driven shaft 14 so as to be integrally rotatable and located between the bearings 18, 19 at both ends thereof and the intermediate shaft 20, respectively. These gears 25 and 26 are stopped from rotation with respect to the driven shaft 14 by keys 27 and 28. The gears 21, 22 of the drive shaft 13 and the gears 25, 26 of the driven shaft 14 mesh with each other, and these gears 21, 22,
With the meshing rotation of 25 and 26, the liquid sucked from the suction port 7 is discharged from the discharge ports 8 and 9.

The distribution wall 10 has a role of dividing the inflowing liquid on the suction side into two, and at the same time forms a holding case for the shafts 17 and 18 in the central portion. Further, it is desirable that each conical portion is formed on the suction side of the distribution wall.

A stuffing box 29 is formed so as to project outward from the front cover 4, and a fitting hole 29a is formed along the center of the stuffing box 29.

One end 13a of the drive shaft 13 has a stuffing box 29.
Of the motor (not shown) is connected to the extending end portion of the motor through the fitting hole 29a. A sleeve 30 is fitted on the outer periphery of the portion of the drive shaft 13 located inside the stuffing box 29. A gland packing 31 is interposed between the outer peripheral surface of the sleeve 30 and the inner peripheral surface of the stuffing box 29. The gland packing 31 is pressed against a step 33 inside the stuffing box 29 by a gland packing retainer 32. The gland packing retainer 32 is attached to the outer surface of the front cover 4 with bolts 34 and nuts 35.

Next, the operation of the gear pump of the present invention having the above structure will be described.

The suction port 7 is connected to an outlet of a single tank (not shown) containing a liquid, and the outlets 8 and 9 are connected to a pressure-fed portion (not shown) such as a mold of a synthetic resin molding machine. Then, when the motor is driven to rotate the drive shaft 13, the gears 21 and 22 rotate integrally with the drive shaft 13. As the gears 21 and 22 rotate, the gears 25 and 26 of the driven shaft 14 meshing with them
Rotate integrally with the driven shaft 14. Each of these gears 21, 22,
After the liquid in the tank is sucked into the suction port 7 from the outlet due to the meshing rotation of 25 and 26, it is divided into two by the action of the distribution wall 10 corresponding to the respective discharge ports 8 and 9. It flows into 11 and 12. Then, the liquid such as high-viscosity polymer that has flown into one of the distribution passages 11 is discharged from one of the discharge ports 8 by the gears 21 and 25 on one side and is pressure-fed to the pressure-fed portion. Also, the liquid that has flowed into the other distribution path 12 side is the gear on the other side.
It is discharged from the other discharge port 9 by 22 and 26 and is pressure-fed to the pressure-fed portion. At this time, between the gears 21 and 22, and between the gears 25 and 26.
Since movable bearings 17 and 20 are interposed between the gears, if the pressure at the discharge ports 8 and 9 becomes a little unbalanced,
21,22 and the gears 25,26 and the bearings 17,20 between them move the bearings 17,22 to the side where the pressure is low by the gap at the time of assembly,
The gap between the gear and the bearing on the high pressure side expands, and by leaking the liquid from this expanded gap, the pressure on the high pressure side discharge port can be slightly lowered to maintain the same pressure as the low pressure side discharge port. I can.

The gear pump of the present invention may be provided with a viscosity measuring gear pump for measuring the viscosity of the liquid so that the viscosity of the liquid to be pumped can be measured. Further, the dimensions of the pair of gears corresponding to the respective ejection ports 8 and 9 may be changed to obtain two different ejection amounts.

 Furthermore, two or more ejection ports may be provided.

(Effects of the Invention) As described in detail above, according to the present invention, a plurality of sets of gears corresponding to the discharge holes are incorporated in the drive shaft and the driven shaft. Although it is possible to accurately divide the discharge amount into multiple by the action,
Since only one pump and its driving machine (motor or the like) are required, the installation space is small and the cost can be smoothly reduced. Further, it is possible to simultaneously withdraw a high-viscosity liquid such as a high-viscosity polymer from the vacuum tank and pressurize the liquid to a high pressure. Further, since the discharge can be performed at a higher pressure than that of the screw pump, the discharge amount is accurate. Furthermore, since a floating type (movable type) is used as the intermediate bearing, it is not necessary to adjust the clearance between the gear and the bearing, and the pump can have a simple structure.
In particular, when each conical portion is formed on the suction side of the distribution wall, when high-viscosity fluid such as high-viscosity polymer is pressure-fed, it is possible to smoothly divide the fluid into each liquid-feeding gear, and the divided fluid The discharge pressure is made uniform by the axial movement of the intermediate part bearing, and the accurate distribution of the high-viscosity fluid is guaranteed by the cooperation of the smooth diversion and the uniformization of the discharge pressure.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a partially cutaway side view of a gear pump of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3 is a sectional view taken along line III-III of FIG. 1, FIGS. 4 and 5 are side views showing different conventional examples, and FIG. 6 is a sectional view showing yet another conventional example. 1 ... Casing, 7 ... Suction port, 8, 9 ... Discharge port, 10
...... Distribution wall, 13 ...... Drive shaft, 14 ...... Drive shaft, 15,16,18,1
9 …… End bearing, 17,20 …… Intermediate bearing, 21,22,25,26…
…gear.

Claims (1)

(57) [Claims] 1. A gear pump that pushes fluid from a suction side to a discharge side by two or more gears that mesh with each other in a casing, wherein the casing has one suction port, at least two discharge ports, and the discharge port. The same number of sets of gears that mesh with each other and intermediate bearings that are located between the gears and respectively support the drive shaft and the driven shaft of the gears are provided, and the intermediate bearings are provided with respect to the drive shaft and the driven shaft. A gear pump characterized by being configured to be movable within a predetermined range in the axial direction.