Insert nut, fastening unit including the insert nut, and process cartridge using the fastening unit

Abstract

An insert nut, which is configured to be inserted into a substrate made of a resin, the insert nut including: an internal thread portion into which a screw is to be fastened; a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and a flange portion formed on one end side in a screw axial direction of the internal thread portion, wherein a nominal diameter of the screw to be fastened into the insert nut is 3 mm or more, and an outer diameter of the flange portion is 2.4 times or more and 4 times or less as large as the nominal diameter of the screw to be fastened into the insert nut.

1 .- 9 . (canceled) 
     
     
         10 . A fastening unit, comprising:
 a screw having a size of M3, of which a nominal diameter is 3 mm, the screw including a shank portion and a head portion, the head portion having a contact portion surrounding the screw shank portion;   an insert nut, which is configured to be inserted into a substrate made of a resin, and into which the screw is to be fastened to fix a member to be fixed to the substrate, the insert nut including:
 an internal thread portion into which the screw having the size of M3 is fastened the contact portion of the screw head portion contacting the member to be fixed; 
 a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and 
 a flange portion formed on one end side in a screw axial direction of the internal thread portion, 
   wherein the flange portion is provided on an upstream end of the insert nut in an insertion direction of the screw,   wherein the contact portion of the screw is positioned on a side of a tip of the screw with respect to a boundary between the screw shank portion and the screw head portion in the insertion direction of the screw and presses the member to be fixed toward the flange portion in the screw axial direction, and   wherein an outer diameter of the flange portion is 7.2 mm or more and 12 mm or less.   
     
     
         11 . An insert nut according to  claim 10 , wherein the outer diameter of the flange portion is 8/3 times or more as large as the nominal diameter of the screw to be fastened into the insert nut. 
     
     
         12 . A process cartridge, comprising an insert nut as recited in  claim 10 . 
     
     
         13 . A fastening unit, comprising:
 a screw having a size of M3, of which a nominal diameter is 3 mm, the screw including a shank portion and a head portion, the head portion having a contact portion surrounding the screw shank portion;   an insert nut, which is configured to be inserted into a substrate made of a resin, and into which the screw is to be fastened to fix a member to be fixed to the substrate, the insert nut including:
 an internal thread portion into which the screw having the size of M3 is fastened the contact portion of the screw head portion contacting the member to be fixed; 
 a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and 
 a flange portion formed on one end side in a screw axial direction of the internal thread portion, 
   wherein the flange portion is provided on an upstream end of the insert nut in an insertion direction of the screw,   wherein the contact portion of the screw is positioned on a side of a tip of the screw with respect to a boundary between the screw shank portion and the screw head portion in the insertion direction of the screw and presses the member to be fixed toward the flange portion in the screw axial direction, and   wherein an outer diameter of the flange portion is 7.5 mm or more.   
     
     
         14 . An insert nut according to  claim 13 , wherein the outer diameter of the flange portion is 8/3 times or more as large as the nominal diameter of the screw to be fastened into the insert nut. 
     
     
         15 . A fastening unit, comprising:
 a screw having a size of M4, of which a nominal diameter is 4 mm, the screw including a shank portion and a head portion, the head portion having a contact portion surrounding the screw shank portion;   an insert nut, which is configured to be inserted into a substrate made of a resin, and into which the screw is to be fastened to fix a member to be fixed to the substrate, the insert nut including:
 an internal thread portion into which the screw having the size of M4 is fastened the contact portion of the screw head portion contacting the member to be fixed; 
 a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and 
 a flange portion formed on one end side in a screw axial direction of the internal thread portion, 
   wherein the flange portion is provided on an upstream end of the insert nut in an insertion direction of the screw,   wherein the contact portion of the screw is positioned on a side of a tip of the screw with respect to a boundary between the screw shank portion and the screw head portion in the insertion direction of the screw and presses the member to be fixed toward the flange portion in the screw axial direction, and   wherein an outer diameter of the flange portion is 8.8 mm or more and 16 mm or less.   
     
     
         16 . An insert nut according to  claim 15 , wherein the outer diameter of the flange portion is 10 mm or more. 
     
     
         17 . A fastening unit, which is configured to fasten a member to be fixed, the fastening unit comprising:
 an insert nut to be inserted into a substrate made of a resin; and   a screw having a size of M3 to be fastened into the insert nut to fix a member to the substrate, a contact portion of a screw head portion of the screw surrounding a screw shank portion of the screw and contacting the member to be fixed,   the insert nut comprising:
 an internal thread portion into which the screw is to be fastened; 
 a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and 
 a flange portion formed on one end side in a screw axial direction of the internal thread portion, 
   wherein a nominal diameter of the screw to be fastened into the insert nut is 3 mm,   wherein the flange portion is provided on an upstream end of the insert nut in an insertion direction of the screw,   wherein the contact portion of the screw is positioned on a side of a tip of the screw with respect to a boundary between the screw shank portion and the screw head portion in the insertion direction of the screw and presses the member to be fixed toward the flange portion in the screw axial direction, and   wherein an outer diameter of the flange portion of the insert nut is equal to or more than 90% of an outer diameter of the contact portion of the screw, which is brought into contact with the member to be fixed, when the screw is fastened.   
     
     
         18 . A fastening unit, which is configured to fasten a member to be fixed, the fastening unit comprising:
 an insert nut to be inserted into a substrate made of a resin; and   a screw having a size of M3 to be fastened into the insert nut to fix a member to the substrate, a contact portion of a screw head portion of the screw surrounding a screw shank portion of the screw and contacting the member to be fixed,   the insert nut comprising:
 an internal thread portion into which the screw is to be fastened; 
 a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and 
 a flange portion formed on one end side in a screw axial direction of the internal thread portion, 
   wherein a nominal diameter of the screw to be fastened into the insert nut is 3 mm,   wherein the contact portion of the screw is positioned on a side of a tip of the screw with respect to a boundary between the screw shank portion and the screw head portion in the insertion direction of the screw and presses the member to be fixed toward the flange portion in the screw axial direction, and   wherein an outer diameter of the flange portion of the insert nut is equal to or more than 90% of an outer diameter of the screw head portion of the screw.   
     
     
         19 . A fastening unit, which is configured to fasten a member to be fixed, the fastening unit comprising:
 an insert nut to be inserted into a substrate made of a resin; and   a screw having a size of M4 to be fastened into the insert nut to fix a member to the substrate, a contact portion of a screw head portion of the screw surrounding a screw shank portion of the screw and contacting the member to be fixed,   the insert nut comprising:
 an internal thread portion into which the screw is to be fastened; 
 a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and 
 a flange portion formed on one end side in a screw axial direction of the internal thread portion, 
   wherein a nominal diameter of the screw to be fastened into the insert nut is 4 mm,   wherein the flange portion is provided on an upstream end of the insert nut in an insertion direction of the screw,   wherein the contact portion of the screw is positioned on a side of a tip of the screw with respect to a boundary between the screw shank portion and the screw head portion in the insertion direction of the screw and presses the member to be fixed toward the flange portion in the screw axial direction, and   wherein an outer diameter of the flange portion of the insert nut is equal to or more than 90% of an outer diameter of the contact portion of the of the screw, which is brought into contact with the member to be fixed, when the screw is fastened.   
     
     
         20 . A fastening unit, which is configured to fasten a member to be fixed, the fastening unit comprising:
 an insert nut to be inserted into a substrate made of a resin; and   a screw having a size of M4 to be fastened into the insert nut to fix a member to the substrate, a contact portion of a screw head portion of the screw surrounding a screw shank portion of the screw and contacting the member to be fixed,   the insert nut comprising:
 an internal thread portion into which the screw is to be fastened; 
 a recess-and-protrusion-shaped portion formed on an outer surface of the insert nut, the recess-and-protrusion-shaped portion including a plurality of ridges and a plurality of roots formed alternately in a circumferential direction; and 
 a flange portion formed on one end side in a screw axial direction of the internal thread portion, 
   wherein a nominal diameter of the screw to be fastened into the insert nut is 4 mm,   wherein the contact portion of the screw is positioned on a side of a tip of the screw with respect to a boundary between the screw shank portion and the screw head portion in the insertion direction of the screw and presses the member to be fixed toward the flange portion in the screw axial direction, and   wherein an outer diameter of the flange portion of the insert nut is equal to or more than 90% of an outer diameter of the screw head portion of the screw.   
     
     
         21 . The fastening unit according to  claim 17 , wherein a of the screw has a dish-like recessed portion, and the contact portion comprises the periphery of the dish-like recessed portion. 
     
     
         22 . The fastening unit according to  claim 19 , wherein a of the screw has a dish-like recessed portion, and the contact portion comprises the periphery of the dish-like recessed portion.