JP5467882B2 - Gear pump - Google Patents

Description

  The present invention relates to a gear pump that transfers a carrier fluid from a suction side to a discharge side while pressurizing the carrier fluid.

A gear pump is often employed as a pump for transferring the molten resin, which is one of the carrier fluids, from the suction side to the discharge side while pressurizing.
An example of a gear pump is disclosed in Patent Document 1. This gear pump has a housing and a pair of gear rotors disposed in the housing and meshing with each other, and each gear rotor has a rotor shaft projecting on both sides. The rotor shaft is rotatably supported in the housing via bearings, and a sliding bearing is adopted for each bearing. As a sliding bearing, a part of the molten resin discharged through both gear rotors is guided to a resin introduction path formed in the housing and supplied as a lubricant to the inner surface of each bearing (sliding surface with the rotor shaft). A self-lubricating type constructed as described above is employed.

Japanese Patent No. 3895537

  In the gear pump provided with the above-described sliding bearing, when the resin pressure (discharge pressure) of the molten resin to be conveyed acts on the gear rotor and the rotor shaft is bent, the outer circumferential surface of the rotor shaft and the bearing in the axial direction of the bearing. There is a possibility that the clearance with the inner peripheral surface of the inner surface of the inner surface of the inner surface is not constant at the same phase in the circumferential direction. That is, the amount of eccentricity between the axis of the rotor shaft and the shaft center of the bearing changes in the axial direction of the rotor shaft, causing a phenomenon of partial contact of the rotor shaft with respect to the bearing (partial contact). There is a great possibility that an increase in shaft rotation resistance and rotation unevenness, abnormal wear of the rotor shaft and bearings, etc. occur.

If the gear pump is increased in size or increased in output, the resin pressure increases, so that the one-side contact phenomenon at the bearing becomes prominent, and the above problem tends to become serious.
The present invention has been made in view of the above circumstances, and prevents the rotor shaft from hitting against a sliding bearing type bearing so that problems such as abnormal wear of the rotor shaft and the bearing can be prevented. An object of the present invention is to provide a gear pump.

In order to achieve the above object, the present invention has taken the following measures.
That is, in the gear pump according to the present invention, a pair of gear rotors that mesh with each other is provided in the housing in a state in which the rotor shafts of the gear rotors are rotatably supported by bearings, and the carrier fluid is sucked in by the rotation of the gear rotors. In the gear pump that feeds from the discharge side to the discharge side, the bearing includes an annular inner ring member that is externally inserted into the rotor shaft, and an annular outer ring member that is provided in the housing and into which the inner ring member is fitted. The inner ring member has an inner peripheral surface that rotatably supports the rotor shaft while being lubricated by a part of the carrier fluid, and the outer ring member is configured to swing the inner ring member following the eccentricity of the rotor shaft. It has an inner peripheral surface that slidably supports the inner ring member as possible.

Preferably, the inner ring member has an outer peripheral surface formed in a convex spherical shape, and the outer ring member has an inner peripheral surface formed in a concave spherical shape in surface contact with the outer peripheral surface of the inner ring member. It is good to have.
Further, the outer ring member can be divided by a radial dividing line passing through the axis of the rotor shaft so that the dividing line does not coincide with the direction of the pressure of the carrier fluid acting on each gear rotor. It is very preferable that the outer ring member is disposed in the housing.

The outer ring member may be provided in the housing so that the dividing line is substantially orthogonal to the direction of the pressure of the carrier fluid acting on each gear rotor.
The most preferred form of the gear pump according to the present invention is a pair of gear looms that mesh with each other.
In the gear pump in which the rotor is provided in the housing with the rotor shaft of each gear rotor rotatably supported by the bearing, and the carrier fluid is sent from the suction side to the discharge side by the rotation of the gear rotor, the bearing includes the bearing An annular inner ring member that is externally inserted into the rotor shaft; and an annular outer ring member that is provided in the housing and into which the inner ring member is fitted, and the inner ring member is formed by a part of the carrier fluid. The outer ring member has an inner peripheral surface that rotatably supports the rotor shaft while being lubricated, and the outer ring member slidably supports the inner ring member so that the inner ring member can swing following the eccentricity of the rotor shaft. The outer ring member has an inner peripheral surface, and can be divided by a radial dividing line passing through the axis of the rotor shaft, and the dividing line is a carrier fluid acting on each gear rotor. Such that the force in the direction not match, the outer ring member is characterized by being deployed in the housing.

  In the gear pump according to the present invention, the one-side contact phenomenon of the rotor shaft with respect to the plain bearing type bearing can be prevented, and problems such as abnormal wear of the rotor shaft and bearing can be prevented.

It is side surface sectional drawing of the gear pump which concerns on this invention. It is front sectional drawing of the gear pump which concerns on this invention. It is a side enlarged view of a bearing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of a gear pump 1 according to the present invention.
The gear pump 1 is provided with a pair of gear rotors 2 that mesh with each other in a housing 3, and rotor shafts 5 that protrude from both sides of the rotor at the center of rotation of the gear rotors 2 are installed in parallel to each other, and Each is supported rotatably by a self-lubricating plain bearing type bearing 6.

This gear pump 1 is employed, for example, when it is provided on the discharge part side (secondary side) of a continuous resin kneader and pressurizes and pushes molten resin (conveying fluid) to a pelletizer or the like.
Details of the gear pump 1 will be described below.
In the following description, the left-right direction in FIG. 1 is referred to as the front-rear direction in the apparatus description, and the up-down direction is referred to as the up-down direction in the apparatus description. The left-right direction in FIG. 2 is referred to as the left-right direction or the width direction in the device description.

As shown in FIGS. 1 and 2, the housing 3 has a block-shaped housing body 10 that is hollow inside. A pair of rotor housing holes 8, 8 are formed inside the housing body 10 so as to be continuous in the vertical direction. The rotor storage holes 8 and 8 that are adjacent to each other in the upper and lower portions overlap and communicate with each other, and have a glasses shape.
Further, a resin inlet 15 and a resin outlet 16 communicating with the rotor storage hole 8 are formed in the front-rear direction of the rotor storage hole 8 and in the center in the width direction.

The gear rotor 2 is inserted into each rotor housing hole 8 and is rotatably supported through bearings 6 and 6.
The gear rotor 2 includes a gear portion 4 that transfers a molten resin, and a rotor shaft 5 that is formed in a protruding shape on both sides of the gear portion 4. The gear portions 4 and 4 of the pair of gear rotors 2 and 2 are disposed in the housing main body 10 in a positional relationship such that they always mesh with each other.

  The bearing 6 that supports the gear rotor 2 is fitted in a bearing hole 9 formed continuously on the left and right sides of the rotor housing hole 8 in an unfixed state. A pair of bearings 6 and 6 arranged vertically are formed on a flat surface by partially cutting out the outer peripheral surfaces adjacent to each other. Therefore, in the state in which the bearings 6 and 6 are housed in the bearing holes 9 and 9, the above-described flat surfaces come into contact with each other to prevent the rotation thereof.

The inner end surface in the width direction of the bearing 6 is substantially in contact with the side surface of the gear portion 4 of the gear rotor 2. The outer end surface of the bearing 6 in the width direction and the end surface of the housing body 10 are substantially flush with each other. The bearing 6 is supported by a bearing retainer 11 (cover body) attached to the end surface of the housing body 10 in the width direction. Outward in the width direction is prevented.
The bearing retainer 11 is attached to the end surface in the width direction of the housing body 10 via a bolt or the like. In addition, the bearing retainer 11 is provided with a pair of seal member insertion holes 33 formed concentrically with the axis of the gear rotor 2, and the Bisco seal 12 is inserted into the seal member insertion holes 33.

  The visco seal 12 has a cylindrical body with a flange, and is fixed to the bearing retainer 11 via bolts or the like so that the flange portion is in contact with the outer end surface of the bearing retainer 11. Further, the visco seal 12 is formed with a flat surface on a part of its outer peripheral surface, and like the bearing 6, the flat surfaces of the pair of visco seals 12 and 12 are prevented from contacting each other and rotating. Yes.

  The width direction inner end surface (end surface on the gear portion side) of the visco seal 12 is in surface contact with the width direction outer end surface (end surface on the counter gear portion side) of the bearing 6. An annular groove 34 communicating with a flow path for returning the molten resin that has lubricated the bearing 6 to the suction side of the gear pump 1 is provided in the surface contact portion around the rotor shaft 5 of the gear rotor 2. The molten resin that has passed in the axial direction of the shaft 5 is prevented from flowing out to the outside by a spiral groove (not shown) provided on the inner surface of the Bisco seal 12.

  Incidentally, one side (the side extending to the right side in FIG. 2) of the rotor shaft 5 of the gear rotor 2 is connected to a drive device (not shown) via a coupling. As shown in FIG. 1, the gear rotors 2, 2 are rotated in opposite directions (arrows X 1, X 2) by this driving device, and the molten resin flows from the resin inlet 15 to the resin outlet 16 by the gear portion 4. It is conveyed under pressure. Therefore, the resin inlet 15 has a molten resin suction action (arrow Y), and the resin outlet 16 has a molten resin push-out action (arrow Z).

  Incidentally, an introduction hole 17 is opened at the resin outlet 16, and this introduction hole 17 communicates with the resin introduction path 20, and this resin introduction path 20 communicates with a lead-out hole 18 that opens to the bearing 6. Yes. Part of the high-pressure molten resin guided to the resin introduction path 20 and discharged through the gear rotor 2 is supplied toward the bearing 6 and becomes part of the lubricant in the bearing 6. A plurality of the resin introduction paths 20 are formed so that at least one is assigned to each bearing 6. In this embodiment, two resin introduction paths 20 are formed in the housing body 10. The introduction hole 17 and the resin introduction path 20 can be provided as necessary.

  As shown in FIGS. 2 and 3, the bearing 6 provided in the gear pump 1 of the present embodiment includes an annular inner ring member 23 that is externally inserted relative to the rotor shaft 5, and an inner ring member 23. And an annular outer ring member 24 that is externally fitted. The outer ring member 24 is fitted into the bearing hole 9 formed in the housing 3 and is pressed by the bearing retainer 11 from the outside in the width direction.

  The inner ring member 23 has a shaft hole 25 through which the inner shaft member 25 is inserted into the rotor shaft 5 in the center. The inner peripheral surface of the shaft hole 25 is supported by the rotor shaft 5 while being lubricated by a part of the molten resin. It is supposed to be. Therefore, the outer ring member 24 and the inner ring member 23 communicate with the outlet hole 18 of the resin introduction path 20, and high-pressure molten resin at the resin outlet 16 passes through the resin introduction path 20 and the inner peripheral surface of the inner ring member 23. The bearing 6 is supplied between the outer peripheral surface of the rotor shaft 5 and operates as a self-lubricating plain bearing.

The outer peripheral surface of the inner ring member 23 is a convex spherical surface 26 formed with an arc curve that swells in the radial direction of the inner ring member 23. In other words, the outer peripheral surface of the inner ring member 23 has a donut-like outer shape.
On the other hand, the outer ring member 24 is formed with an opening for fitting the inner ring member 23 in the center thereof, and the inner peripheral surface of this hole can contact the convex spherical surface 26 of the inner ring member 23 by a face-to-face connection. The concave spherical surface 27 is formed. The convex spherical surface 26 is slidable with respect to the concave spherical surface 27, so that the inner ring member 23 can swing with respect to the outer ring member 24.

  The radius of curvature of the convex spherical surface 26 (in other words, the radius of curvature of the concave spherical surface 27) is constant, and from any position on the spherical surface to the center so that the inner ring member 23 can follow the eccentricity of the rotor shaft 5. Are set to have the same distance. It should be noted that the radius of curvature of the convex spherical surface 26 and the radius of curvature of the concave spherical surface 27 are ideally the same, but the convex spherical surface 26 and the concave spherical surface 27 maintain the surface contact state while the convex spherical surface 26 is maintained. Is set to be “substantially the same” so that both can be slidable with respect to the concave spherical surface 27.

The concave spherical surface 27 and the convex spherical surface 26 are preferably formed of a material having self-lubricating properties such as spheroidal graphite cast iron.
On the other hand, as shown in FIG. 3, the outer ring member 24 constituting the bearing 6 can be divided into two semicircular half members 31 and 32 with a radial dividing line 30 passing through the axis of the rotor shaft 5 as a boundary. The half members 31 and 32 are coupled to face each other so as to exhibit an annular shape that can sandwich the inner ring member 23.

The dividing line 30 of the outer ring member 24 is inconsistent with the direction of the resin pressure acting on the gear rotor 2 from the resin outlet 16 side toward the resin inlet 15 side (the direction of the molten resin discharge pressure). An outer ring member 24 is disposed in the housing 3.
That is, when the gear rotors 2 and 2 meshing with each other are rotated, the molten resin is transported between the gear portion 4 of each gear rotor 2 and the inner peripheral surface of the rotor housing hole 8, and at a stroke from the merging position G toward the resin outlet 16. Be pushed out. Therefore, a phenomenon occurs in which the resin pressure of the molten resin becomes the highest at the junction G. Such a resin pressure acts to push the gear rotor 2 back to the resin inlet 15 side (low pressure side), and causes each rotor shaft 5 of the gear rotor 2 to bend.

  Therefore, if the split line 30 of the outer ring member 24 is arranged in the same direction as the direction of the resin pressure, the resin pressure causes the half members 31 and 32 of the outer ring member 24 to be displaced in the radial direction. As a result, there is no continuity in the circumferential direction of the concave spherical surface 27 between the half members 31 and 32, and there is a possibility that the slip between the concave spherical surface 27 and the convex spherical surface 26 of the inner ring member 23 is deteriorated. Therefore, in order to prevent this phenomenon, the dividing line 30 does not coincide with the direction of the resin pressure as described above.

  In the upper outer ring member 24 shown in FIG. 3, when the discharge side is set to 0 ° and the coordinates are divided counterclockwise, the resin pressure acting on the upper gear rotor 2 is indicated by an arrow F (second quadrant). It has become clear that it works. In view of such a result, it is preferable to arrange the dividing line 30 so as to cross two symmetrical points within the range of the first quadrant and the range of the third quadrant and pass through the axis of the rotor shaft 5.

Moreover, it has become clear as a result that the resin pressure acting on the lower gear rotor 2 acts in the arrow F ′ (third quadrant). In view of such results, it is preferable to arrange the dividing line 30 so as to cross two symmetrical points in the range of the second quadrant and the range of the fourth quadrant and pass through the axis of the rotor shaft 5.
In the present embodiment, as shown in FIG. 3, with respect to the outer ring member 24 that supports the upper gear rotor 2, the dividing line 30 is disposed so as to cross the positions of 45 ° and 225 °, and the resin pressure acting direction F (About 135 °). Further, with respect to the outer ring member 24 that supports the lower gear rotor 2, a dividing line 30 is disposed so as to cross the positions of 135 ° and 315 °, and is orthogonal to the resin pressure acting direction F ′ (about 225 °). I am letting.

The operation mode of the gear pump 1 of the present invention having the above-described configuration is as follows.
When the drive device that drives the gear pump 1 is operated, the gear rotor 2 rotates in the opposite direction (arrows X1, X2) due to meshing, as shown in FIG. Is conveyed from the resin inlet 15 to the resin outlet 16. At the resin inlet 15, the molten resin flows as indicated by a symbol Y and is pressurized by conveyance by the gear portion 4, and at the resin outlet 16, the molten resin that has reached a high pressure passes through a joining position G as indicated by a symbol Z. Discharge.

Since the molten resin at the resin outlet 16 is at a high pressure, a resin pressure is generated so as to push back the gear portion 4 of the gear rotor 2 supported at both ends by the bearings 6 and 6 toward the resin inlet 15 side, that is, the rear side.
As a result, even if the rotor shaft 5 is deflected and the axis of the rotor shaft 5 is inclined, the convex spherical surface 26 of the inner ring member 23 in the bearing 6 provided in the gear pump 1 is compared with the concave spherical surface 27 of the outer ring member 24. By sliding, an appropriate angle adjustment (self-aligning action) occurs between the inner ring member 23 and the outer ring member 24. Since this self-aligning action allows the rotor shaft 5 to bend, the rotor shaft 5 and the shaft hole 25 of the bearing 6 (inner ring member 23) maintain a constant axial clearance. .

As a result, the outer peripheral surface of the rotor shaft 5 does not cause a one-side contact phenomenon with respect to the shaft hole 25 of the inner ring member 23, and the rotation resistance of the rotor shaft 5, uneven rotation, single wear of the rotor shaft 5 and the bearing 6, etc. The problem can be prevented beforehand.
That is, according to the gear pump 1 of the present invention, the molten resin can be reliably transferred from the suction side to the discharge side while being pressurized, and the perimeter phenomenon of the outer peripheral surface of the rotor shaft 5 with respect to the inner peripheral surface of the bearing 6 during operation. , And problems such as abnormal wear of the rotor shaft 5 and the bearing 6 can be prevented.

In addition, this invention is not limited to the said embodiment, It can change suitably according to embodiment.
For example, the use as the gear pump 1 and the transport fluid are not limited to molten resin.
The dividing line 30 is not limited to be provided in a straight line in the radial direction with respect to the outer ring member 24 of the bearing 6. For example, three dividing lines 30 are provided in a Y shape so that the outer ring member 24 extends in the circumferential direction. It is also possible to divide into three parts.

DESCRIPTION OF SYMBOLS 1 Gear pump 2 Gear rotor 3 Housing 4 Gear part 5 Rotor shaft 6 Bearing 8 Rotor accommodation hole 9 Bearing hole 10 Housing main body 11 Bearing retainer 12 Visco seal 15 Resin inlet 16 Resin outlet 17 Introduction hole 18 Lead-out hole 20 Resin introduction path 23 Inner ring member 24 Outer ring member 25 Inner ring member shaft hole 26 Convex spherical surface 27 Concave spherical surface 30 Dividing line 31 Half member 32 Half member 33 Seal member insertion hole 34 Annular groove

Claims (3)

In a gear pump in which a pair of gear rotors engaged with each other is provided in the housing in a state where the rotor shaft of each gear rotor is rotatably supported by a bearing, and the carrier fluid is sent from the suction side to the discharge side by the rotation of the gear rotor.
The bearing includes an annular inner ring member that is externally inserted into the rotor shaft, and an annular outer ring member that is provided in the housing and into which the inner ring member is fitted, and the inner ring member The outer ring member has an inner peripheral surface that rotatably supports the rotor shaft while being lubricated by a part of the fluid, and the outer ring member slides the inner ring member so that the inner ring member can swing following the eccentricity of the rotor shaft. It has an inner peripheral surface that supports it freely ,
The outer ring member can be divided by a radial dividing line passing through the axis of the rotor shaft, and the dividing line is inconsistent with the direction of the pressure of the carrier fluid acting on each gear rotor. An outer ring member is provided in a housing . The inner ring member has an outer peripheral surface formed in a convex spherical shape,
2. The gear pump according to claim 1, wherein the outer ring member has an inner circumferential surface formed in a concave spherical shape in surface contact with the outer circumferential surface of the inner ring member. The gear pump according to claim 1 or 2 , wherein the outer ring member is disposed in the housing so that the dividing line is substantially orthogonal to the direction of the pressure of the carrier fluid acting on each gear rotor.

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