Gear pump

Abstract

A gear pump applicable for feeding a high-pressure and high-viscosity fluid, such as a molten resin is provided. In the gear pump 100 , the fluid is fed from a suction port side to a discharge port side by the rotation of gears. The gears are formed in a pair and meshing with each other. The gears are double-helical gears having a one-point continuous contact tooth profile. For the gears, the ratio D/B of the outer diameter D and the tooth width B are set to 1.1 to 1.15. When the ratio D/B is equal to or smaller than 1.1, a bearing may be damaged due to an excessively increased bearing load. On the other hand, when the ratio D/B is larger than 1.15, in accordance with an increase in the overall size of the pump external dimension, the mechanical efficiency is lowered, and the overall efficiency is also lowered.

1 . A gear pump, comprising:
 a casing, having a suction port for guiding in a fluid and a discharge port for discharging the fluid; and   a pair of gears, disposed within the casing, wherein the fluid is fed from the suction port to the discharge port by a rotation of the gears meshing with each other, the pair of the gears is double-helical gears having a one-point continuous contact tooth profile, and a ratio of a gear diameter to a gear width of each gear is set to 1.1 to 1.15.   
   
   
       2 . The gear pump as claimed in  claim 1 , wherein a number of teeth for the gear is 10˜12, and a twisting angle of the gear is 28°˜32°. 
   
   
       3 . The gear pump as claimed in  claim 1 , wherein in an inner peripheral profile of the casing, an angle formed by line segments respectively connected between positions where each tooth tip of the rotating gear departs from an inner peripheral surface of the casing and a position of a pitch point of the gear is 48° to 102° as seen from the section of the axis direction. 
   
   
       4 . The gear pump as claimed in  claim 2 , wherein in an inner peripheral profile of the casing, an angle formed by line segments respectively connected between positions where each tooth tip of the rotating gear departs from an inner peripheral surface of the casing and a position of a pitch point of the gear is 48°˜102° as seen from the section of the axis direction. 
   
   
       5 . The gear pump as claimed in  claim 1 , wherein in an inner peripheral profile of the casing,
 a circular-arc angle formed between a position where a tooth tip of the rotating gear approaches closely to an inner peripheral surface of the casing and a position where a tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction.   
   
   
       6 . The gear pump as claimed in  claim 2 , wherein in an inner peripheral profile of the casing,
 a circular-arc angle formed between a position where a tooth tip of the rotating gear approaches closely to an inner peripheral surface of the casing and a position where the tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction.   
   
   
       7 . The gear pump as claimed in  claim 3 , wherein in the inner peripheral profile of the casing,
 a circular-arc angle formed between a position where the tooth tip of the rotating gear approaches closely to the inner peripheral surface of the casing and a position where the tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction.   
   
   
       8 . The gear pump as claimed in  claim 4 , wherein in the inner peripheral profile of the casing,
 a circular-arc angle formed between a position where the tooth tip of the rotating gear approaches closely to the inner peripheral surface of the casing and a position where the tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction.   
   
   
       9 . A method for manufacturing a high molecular polymer, a molten resin, or a molding thereof, wherein the gear pump as claimed in  claim 1  is used in a process for manufacturing the high molecular polymer or the molten resin, or in a process for manufacturing the molding of the high molecular polymer or the molten resin. 
   
   
       10 . A method for manufacturing a high molecular polymer, a molten resin, or a molding thereof, wherein the gear pump as claimed in  claim 2  is used in a process for manufacturing the high molecular polymer or the molten resin, or in a process for manufacturing the molding of the high molecular polymer or the molten resin. 
   
   
       11 . A polymerization apparatus, using the gear pump as claimed in  claim 1 . 
   
   
       12 . A polymerization apparatus, using the gear pump as claimed in  claim 2 . 
   
   
       13 . A molding apparatus, using the gear pump as claimed in  claim 1 . 
   
   
       14 . A molding apparatus, using the gear pump as claimed in  claim 2 . 
   
   
       15 . A fiber spinning apparatus, using the gear pump as claimed in  claim 1 . 
   
   
       16 . A fiber spinning apparatus, using the gear pump as claimed in  claim 2 . 
   
   
       17 . A gear pump, comprising:
 a casing, having a suction port for guiding in a fluid and a discharge port for discharging the fluid; and   a pair of gears, disposed within the casing, wherein the fluid is fed from the suction port to the discharge port by a rotation of the gears meshing with each other, the pair of the gears is helical gears having a one-point continuous contact tooth profile, and a ratio of a gear diameter to a gear width of each gear is set to 1.1˜1.15.   
   
   
       18 . The gear pump as claimed in  claim 17 , wherein a number of teeth of the gear is 8˜12, and a twisting angle of the gear is 14°˜18°. 
   
   
       19 . The gear pump as claimed in  claim 17 , wherein in an inner peripheral profile of the casing, an angle formed by line segments respectively connected between positions where each tooth tip of the rotating gear departs from an inner peripheral surface of the casing and a position of a pitch point of the gear is 48°˜102° as seen from the section of the axis direction. 
   
   
       20 . The gear pump as claimed in  claim 18 , wherein in an inner peripheral profile of the casing, an angle formed by line segments respectively connected between positions where each tooth tip of the rotating gear departs from an inner peripheral surface of the casing and a position of a pitch point of the gear is 48°˜102° as seen from the section of the axis direction. 
   
   
       21 . The gear pump as claimed in  claim 17 , wherein in an inner peripheral profile of the casing, a circular-arc angle formed between a position where a tooth tip of the rotating gear approaches closely to an inner peripheral surface of the casing and a position where the tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction. 
   
   
       22 . The gear pump as claimed in  claim 18 , wherein in an inner peripheral profile of the casing, a circular-arc angle formed between a position where a tooth tip of the rotating gear approaches closely to an inner peripheral surface of the casing and a position where a tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction. 
   
   
       23 . The gear pump as claimed in  claim 19 , wherein in the inner peripheral profile of the casing,
 a circular-arc angle formed between a position where the tooth tip of the rotating gear approaches closely to an inner peripheral surface of the casing and a position where the tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction.   
   
   
       24 . The gear pump as claimed in  claim 20 , wherein in the inner peripheral profile of the casing, a circular-arc angle formed between a position where the tooth tip of the rotating gear approaches closely to an inner peripheral surface of the casing and a position where the tooth tip of the gear departs from the inner peripheral surface of the casing is 72°˜108° as seen from the section of the axis direction. 
   
   
       25 . A method for manufacturing a high molecular polymer, a molten resin, or a molding thereof, wherein the gear pump as claimed in  claim 17  is used in a process for manufacturing the high molecular polymer or the molten resin, or in a process for manufacturing the molding of the high molecular polymer or the molten resin. 
   
   
       26 . A method for manufacturing a high molecular polymer, a molten resin, or a molding thereof, wherein the gear pump as claimed in  claim 18  is used in a process for lo manufacturing the high molecular polymer or the molten resin, or in a process for manufacturing the molding of the high molecular polymer or the molten resin. 
   
   
       27 . A polymerization apparatus, using the gear pump as claimed in  claim 17 . 
   
   
       28 . A polymerization apparatus, using the gear pump as claimed in  claim 18 . 
   
   
       29 . A molding apparatus, using the gear pump as claimed in  claim 17 . 
   
   
       30 . A molding apparatus, using the gear pump as claimed in  claim 18 . 
   
   
       31 . A fiber spinning apparatus, using the gear pump as claimed in  claim 17 . 
   
   
       32 . A fiber spinning apparatus, using the gear pump as claimed in  claim 18 .