JP2007021699A - Method for finishing head part of screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for finishing a head part of a screw for obtaining fixed finishing accuracy, regardless of experience and skillfulness of a worker. <P>SOLUTION: In this method, a liner 9 is fixed to an internal surface of a casing 1 by the screw 12, and the head part 13 of the screw 12 is finished to be flush with the surface of the liner 9. In the part of the casing 1 adjacent to the screw 12, a finishing device 17 having a grinding tool 21 movable and rotatable in the vertical direction is installed. By moving the grinding tool 21 downward, while rotating the grinding tool 21 by an operation of the finishing device 17, the head part 13 of the screw 12 projected from the surface of the liner 9 is ground and eliminated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for finishing a screw head, for example, finishing a screw head suitable for finishing a screw head for fixing a liner attached to the casing inner surface of a turbine used for hydropower generation to the casing. Regarding the method.

  As an example of a water turbine used for hydroelectric power generation, water is led from an inflow channel into a spiral casing, the water is guided to a guide vane through a stay vane, rectified by the guide vane, then guided to the runner, and the runner is driven to rotate. A configuration is known in which the main shaft of a generator is driven to rotate integrally with the runner, and water that has passed through the runner is discharged into a drainage channel.

  In the water wheel having such a configuration, a liner is attached to a portion of the casing on the inner surface where the guide vane is provided by a screw, and this liner reduces resistance when water passes through the guide vane, and wear due to water flow. Is prevented from reaching the casing, and the worn part can be repaired simply by replacing the worn liner.

  A flat head screw is used as a screw for fixing the liner to the casing. The flat head screw is inserted into the screw hole of the casing through the liner and tightened with a predetermined torque to fix the liner to the casing. Yes.

Further, after fixing the liner to the casing from the countersunk screw, a sander as described in Patent Document 1 is used to grind the part of the countersunk screw (part of the head) protruding from the surface of the liner. The top surface of the screw head and the surface of the liner are finished flush.
JP-A-8-281548

  By the way, in the method of grinding a part of the head of the countersunk screw with the sander as described above, the operator must hold the sander by hand and finish it manually. The finishing accuracy varies depending on the skill level, and a certain finishing accuracy cannot be obtained. In addition, since the work must be performed while holding the sander by hand, workability is very poor and work efficiency is deteriorated. Furthermore, since the angle of contact with the screw of the sander is not constant, it is difficult to predict the scattering direction of the grinding powder and the grinding pieces, and it takes much time to install the curing for protecting peripheral devices.

  The present invention has been made in view of the conventional problems as described above, and a predetermined constant finishing accuracy can be obtained even by an inexperienced worker regardless of the experience and skill level of the worker. Another object of the present invention is to provide a method for finishing the head of a screw that has high workability, can improve work efficiency, and can easily cure peripheral devices.

In order to solve the above problems, the present invention employs the following means.
That is, the invention according to claim 1 is a screw head finishing method for fixing a liner to an inner surface of a casing with a screw and finishing the screw head so as to be flush with the surface of the liner. A finishing device having a grinding tool that is movable in the vertical direction and is rotatable in a portion adjacent to the screw, and moving the grinding tool downward while rotating the grinding tool by the operation of the finishing device, A portion of the screw head protruding from the surface of the liner is ground to finish the screw head flush with the surface of the liner.

  According to the method for finishing a screw head according to the present invention, a finishing device is installed in a portion close to the screw for fixing the liner to the casing, and this finishing device is operated to move the grinding tool downward while rotating. Thus, a part of the screw head protruding from the surface of the liner is ground by the grinding tool, and the upper surface of the screw head is finished flush with the surface of the liner.

  The invention according to claim 2 is the screw head finishing method according to claim 1, wherein as the finishing device, a main body portion fixed to the casing by fixing means, and the main body portion can be moved up and down. A device comprising a movable part supported by the movable part, a grinding tool rotatably provided on the movable part, and an operation handle for moving the movable part up and down is used.

  According to the screw head finishing method of the present invention, the main body of the finishing device is fixed to a portion close to the screw for fixing the liner to the casing, and the movable handle is operated by operating the operation handle while rotating the grinding tool. By moving downward, the grinding tool contacts the screw head protruding from the surface of the liner, part of the screw head is ground, and the upper surface of the screw head is flush with the surface of the liner. It will be finished.

  A third aspect of the present invention is the screw head finishing method according to the second aspect, wherein a magnet or vacuum suction is used as the fixing means.

  According to the screw head finishing method of the present invention, the main body of the finishing device is magnetically attached to the casing by a magnet, or is attracted to the casing by vacuum suction and is fixed to the casing.

  The invention according to claim 4 is the screw head finishing method according to claim 2 or 3, wherein the grinding tool is formed to have a diameter larger than the diameter of the screw head. Features.

  According to the method for finishing a screw head according to the present invention, the diameter of the grinding tool is formed larger than the diameter of the screw head. Grinding can be performed by moving up and down, and work efficiency can be improved.

  The invention according to claim 5 is the screw head finishing method according to any one of claims 1 to 4, characterized in that a curing is provided to surround a grinding portion by the grinding tool.

  According to the screw head finishing method of the present invention, since the grinding portion by the grinding tool can be surrounded by curing, it is possible to prevent grinding powder, grinding pieces, etc. generated by grinding from reaching peripheral equipment.

Hereinafter, embodiments of the present invention shown in the drawings will be described.
FIG. 1 and FIG. 2 show an embodiment of a screw head finishing method according to the present invention. FIG. 1 shows a hydroelectric power turbine to which the screw head finishing method of the present invention is applied. FIG. 2 is a schematic view showing a procedure of a method for finishing a screw head.

  As shown in FIG. 1, a hydroelectric turbine is provided in a casing 1 having an inflow passage 3, a runner 4 provided at the center of the casing 1, and a communication portion 5 between the runner 4 of the casing 1 and the inflow passage 3. The guide vane 6 and the stay vane 7 are provided, and the main shaft 8 of the generator is connected to the center of the runner 4.

  A sheet-like liner 9 is integrally attached to the attachment portion of the guide vane 6 of the communication portion 5 of the casing 1. The liner 9 prevents wear of the communication portion 5 and increases the smoothness of the communication portion 5. Thus, the resistance acting on the water flowing through the communication portion 5 is reduced.

  As shown in FIG. 2, the liner 9 is provided with a plurality of screw insertion holes 10 penetrating between the front and back surfaces. Each screw insertion hole 10 is formed in a tapered recess 11 having a tapered surface with a predetermined angle on the upper half of the surface side, and a head 13 of a screw 12 described later is engaged in the tapered recess 11.

  As shown in FIG. 2, a screw hole 2 having a predetermined depth is screwed into the communication portion 5 of the casing 1 corresponding to each screw insertion hole 10 of the liner 9. The liner 9 is fixed to the casing 1 by screwing the screw 12 inserted through the hole 10 into the screw hole 2 and tightening.

  The screw 12 is a countersunk screw composed of an inverted frustoconical head 13 and a round bar-shaped screw 14 integrally provided at the center of the lower end of the head 13, and the head 13 is a tapered recess 11 of the liner 9. The screw portion 14 is inserted into the screw insertion hole 10 of the liner 9 and screwed into the screw hole 2 of the casing 1.

  At the center of the upper end of the head 13 of the screw 12, a spanner hooking portion 15 having an outer diameter of hexagonal shape is integrally connected via a leg 16 having a round bar shape, and a spanner is hung on the spanner hooking portion 15 or a box. By screwing the box of the wrench and turning the spanner or the box wrench, the screw 12 can be tightened with a larger torque than turning the head 13 of the screw 12 with a screwdriver. The spanner hook 15 is threaded by the tightening torque at the leg 16, and when the screw head is finished in the present embodiment, only the threaded mark of the leg 16 remains on the screw head. In addition, what is necessary is just to provide the spanner hook part 15 in the head 13 of the screw | thread 12 as needed.

  As shown in FIG. 2, the finishing device 17 includes a main body 18, a fixing means 19 that fixes the main body 18 to the casing 1, a movable part 20 that is provided on the main body 18 so as to be movable up and down, A grinding tool 21 that is rotatably provided at the lower end portion, a drive source (not shown) that drives the grinding tool 21 to rotate, and an operation handle 22 that moves the movable part 20 up and down are provided. Examples of the finishing device 17 include a drilling machine.

  The fixing means 19 is, for example, a magnet or vacuum suction. The main body 18 is magnetically attached to the casing 1 by the magnetic force of the magnet, the main body 18 is attracted to the casing 1 by vacuum suction, and the entire finishing device 17 is attached to the casing 1. Fixed.

  The grinding tool 21 is, for example, a grindstone (cutting edge), and one having an outer diameter D larger than the outer diameter D ′ of the screw 12 is used as shown in FIG. By using the grinding tool 21 having such an outer diameter D, the entire area of the screw 12 can be ground by a single vertical movement of the grinding tool 21, so that the working efficiency can be improved.

  In order to finish the head portion 13 of the screw 12 using the finishing device 17 having the above-described configuration, first, the finishing device 17 is attached to a portion close to the screw 12 that fixes the liner 9 to the casing 1. It is installed and the main body 18 is fixed to the casing 1 by the fixing means 19. In this case, the finishing device 17 is fixed so that the center of the screw 12 is positioned at the center of the grinding tool 21.

  Then, the drive source is operated to rotate the grinding tool 21, and in this state, the operation handle 22 is operated to lower the movable part 20. The grinding tool 21 is lowered integrally with the movable part 20, and the grinding tool 21 is moved to the liner. The leg portion 16 is ground and removed by contacting the screw 12 protruding from the surface of 9 and moving the grinding tool 21 downward via the movable portion 20. Then, the grinder 21 is further moved downward via the movable portion 20 to grind and remove the upper end portion of the head portion 13 of the screw 12 protruding from the surface of the liner 9.

  In this case, the curing is installed so as to surround the periphery of the grinding portion by the grinding tool 21, and the cutting powder and cutting pieces of the screw 12 by the grinding tool 21 are prevented from reaching the surrounding equipment. Since the grinding tool 21 comes into contact with the screw 12 from above and below, the direction in which the cutting powder and the cutting pieces are scattered can be predicted, and the setting of the curing is easy. In addition, you may make it surround not only a grinding part but the whole finishing apparatus 17 with curing.

  Thus, the upper surface of the head 13 of the screw 12 is made flush with the surface of the liner 9 by grinding and removing the leg 16 of the screw 12 protruding from the liner 9 and the upper end of the head 13. be able to. Then, by performing such a finishing operation for each screw 12, the upper surfaces of the heads 13 of all the screws 12 are finished flush with the surface of the liner 9.

  In the screw head finishing method according to the present embodiment configured as described above, the finishing device 17 is installed in the portion of the casing 1 close to the screw 12, and the finishing device 17 is operated to operate the grinding tool. The grinder 21 is lowered integrally with the movable portion 20 by operating the operation handle 22 while rotating the 21, so that the spanner hooking portion 15, the leg portion 16, and the head portion 13 of the screw 12 protruding from the surface of the liner 9. Can be ground and removed.

  In this case, the operator only has to install the finishing device 17 at a predetermined position of the casing 1, center the grinding tool 21 and the screw 12, operate the finishing device 17, and operate the operation handle 22. Therefore, regardless of the operator's experience and skill level, even an inexperienced operator can finish the portion of the screw 12 protruding from the liner 9 flush with the liner 9 with a predetermined finishing accuracy.

  Further, since it is only necessary to operate the operation handle 22, it is not necessary to bend and perform work unlike the conventional method using a sander, and workability can be improved and work efficiency can be improved.

  Furthermore, since the screw 12 is ground from the same direction by the grinding tool 21, it is possible to easily predict the scattering direction of the grinding powder and the grinding piece, and it is easy to install the curing for protecting surrounding equipment. This also increases the work efficiency.

  In the above invention, the screw head finishing method according to the present invention is applied to the finishing of the screw 12 for fixing the liner 9 of the turbine to the casing 1. However, the present invention may be applied to other devices, machines, facilities, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is the example of application of one Embodiment of the finishing method of the screw head by this invention, Comprising: It is the principal part expanded sectional view of the water turbine of a hydroelectric power generation. It is the schematic which showed the procedure of the finishing method of the head of the screw by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Screw hole 3 Inflow path 4 Runner 5 Communication part 6 Guide vane 7 Stay vane 8 Spindle 9 Liner 10 Screw insertion hole 11 Taper recessed part 12 Screw 13 Head 14 Screw part 15 Spanner hook part 16 Leg part 17 Finishing device 18 Main body 19 Fixing means 20 Movable part 21 Grinding tool 22 Operation handle

Claims (5)

A method of finishing a screw head for fixing a liner to an inner surface of a casing with a screw, and finishing the head of the screw so as to be flush with the surface of the liner,
By installing a finishing device having a grinding tool that is movable in the vertical direction and rotatable in a portion close to the screw, and moving the grinding tool downward while rotating the grinding tool by the operation of the finishing device, the screw A method of finishing a screw head, comprising grinding a portion of the head of the head protruding from the surface of the liner and finishing the head of the screw flush with the surface of the liner.   As the finishing device, a main body part fixed to the casing by a fixing means, a movable part supported by the main body part so as to be movable up and down, a grinding tool provided rotatably on the movable part, and the movable part 2. The method for finishing a screw head according to claim 1, wherein an apparatus having an operation handle that moves up and down is used.   The screw head finishing method according to claim 2, wherein a magnet or vacuum suction is used as the fixing means.   4. The method for finishing a screw head according to claim 2, wherein the grinding tool is formed to have a diameter larger than a diameter of the screw head. The method for finishing a screw head according to any one of claims 1 to 4, further comprising providing a curing surrounding a portion ground by the grinding tool.

Images