JP2007239932A - Fastening device, and fastening method using the fastening device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fastening device and a fastening method capable of easily and accurately carrying axial force management. <P>SOLUTION: The fastening device is provided with a bolt member 2 provided with a shaft part 2a having a male screw 2c, and a head part 2b, a load transmitting member 3 attached around the shaft part 2a and capable of transmitting force to a material to be fastened, an elastic body 4 arranged between the head part 2b and the load transmitting member 3 and capable of transmitting force (axial force) in an axial direction of the bolt member to the head part 2b and the load transmitting member 3, and a constraining means 5 for constraining relative movements of the bolt member 2 and the load transmitting member 3 by predetermined frictional force, and capable of maintaining an initial state wherein the elastic body 4 is in a state capable of transmitting axial force to the head part 2b and the load transmitting member 3 and axial force is not generated in the elastic body 4. In the fastening device and the fastening method, the bolt member 2 is turned for just a predetermined angle from the initial state with respect to the load transmitting member 3, and the elastic body is compressed for just a screwing amount corresponding to the predetermined angle, and by this, the material to be fastened is fastened by fastening force corresponding to the predetermined angle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fastening device and a fastening method using screws, and more particularly, to a fastening device and a fastening method used for an application that requires accurate tightening force management.

Fastening members using screws such as bolts and nuts are widely used in all technical fields as the most basic mechanical elements. Among them, in an apparatus that requires high assembly accuracy, accurate management of the tightening force by the fastening member is an important issue.
One application that requires this precise clamping force management is, for example, assembly of a die head of a slit coater used in the field of semiconductor manufacturing. When assembling the die head, it is necessary to keep the very narrow slit width of the die head nozzle uniform, so in order to maintain the accuracy of the bolt tightening force, the bolt axial force is usually managed using a torque wrench. Yes.

  That is, since the torque for rotating the bolt is converted into the axial force of the bolt, the idea is to manage the tightening force of the material to be fastened by managing the torque for rotating the bolt. Here, the axial force of the bolt generated when the screw is tightened is accumulated by the tensile deformation of the bolt and the compressive deformation of the material to be fastened, and the frictional force between the threads of the screw and the bearing surface of the bolt head. It is held by the frictional force between the material to be fastened. However, when a normal bolt is screwed in, the frictional force between the threads of the screw has a great influence. In the case of normal tightening, axial force is obtained by deformation of the bolt and the material to be fastened. Therefore, even if the bolt has a very small rotation variation (for example, 5 degrees or less), a very large axial force variation occurs. Further, the axial force stored by deformation of the bolt and the material to be fastened easily changes due to thermal expansion / contraction due to temperature change.

  Further, the torque for rotating the bolt for screwing is composed of a frictional force between the threads of the male and female threads generated by the axial force. The coefficient of friction between the thread ridges varies greatly depending on the state of lubrication, the degree of drying, the surface roughness of the thread surface, and the like. Therefore, the axial force changes greatly even if the bolt is tightened with the same rotational torque due to the change in the coefficient of friction between the threads of the screw. Therefore, the axial force changes between the first tightening and the first tightening after loosening.

  Therefore, in assembling the die head using a torque wrench, the axial force changes in the order in which the bolts are tightened. Therefore, in order to finally tighten with the same axial force, it is necessary to repeat the tightening many times. In particular, in the case of a stainless steel screw, there is a high possibility that excessive tightening will occur. In this case, care should be taken because seizure or large elastic deformation may occur.

In order to cope with such an application that requires accurate management of the axial force of the bolt, for example, a device that manages the tightening force using a disc spring has been proposed. (For example, refer to Patent Document 1.)
JP 2000-78706 A

Patent Document 1 describes an invention in which a ground coil body for a magnetically levitated railway is attached to a track by pressing a disc spring with a bolt and nut. In this invention, since the axial force is generated by the pressed disc spring, the influence of the friction coefficient between the bolts and nuts is not affected, and the influence of the ambient temperature during the operation can be suppressed, so that the axial force management is easily performed. be able to.
Further, the present invention has a structure in which the height of the pressed disc spring is always a constant value h when the bolt and nut are tightened. Therefore, if the disc spring is manufactured with a very high accuracy, and the initial height h ₀ of the disc spring (the height when the disc spring is not deformed without receiving a load) always has an accurate constant value, When the disc spring is pressed so that its height becomes h, a constant axial force is always generated by the pressed disc spring.

  However, the accuracy of manufacturing an actual disc spring is not so high. In particular, when a plurality of disc springs are combined, the cumulative error of the height dimension becomes even larger. Therefore, as shown in Patent Document 1, when the height of the disc spring is always pressed to a constant value h, the axial force generated by the attached disc spring may be different. It is difficult to use in applications that require high assembly accuracy, such as die heads. Further, when the plate spring is released after being tightened once, the height of the disc spring changes. Therefore, when the tightening and releasing are repeated a plurality of times, the axial force further changes.

  Therefore, the object of the present invention is to solve the above-mentioned problems, and to easily and accurately manage the axial force, and in particular, it is possible to always generate an accurate axial force even when an elastic body having a low dimensional system is used. Furthermore, another object of the present invention is to provide a fastening device that is not easily affected by environmental changes and a fastening method using the fastening device.

  In order to solve the above-described problem, one embodiment of the fastening device of the present invention includes a bolt member including a shaft portion having a male screw and a head portion, and a ring member attached to the shaft portion, A load transmitting member capable of transmitting a force, and disposed between the head portion and the load transmitting member, and an axial force (axial force) of the bolt material is applied to the head portion and the load transmitting member. The elastic body transmits the axial force to the head portion and the load transmission member by restraining the relative movement between the bolt member and the load transmission member by a transferable elastic body and a predetermined frictional force. And a restraining means capable of maintaining an initial state in which the axial force is not generated in the elastic body, and the bolt member from the initial state with respect to the load transmitting member. Rotate by a predetermined angle, corresponding to the predetermined angle By compressing the elastic body only di inclusive amount, characterized by fastening the fastened material in the clamping force corresponding to the predetermined angle.

  In this embodiment, the elastic member is disposed between the head portion of the bolt member and the load transmission member that is mounted on the shaft portion of the bolt member, and the male screw of the bolt member is connected to the material to be fastened. The material to be fastened is fastened by screwing into the female screw on the side. At this time, the elastic body disposed between the head portion and the load transmission member is compressed by the screwing amount corresponding to the rotation angle from the initial state (with respect to the load transmission member) of the bolt member, and is generated by this compression. The axial force thus transmitted is transmitted to the material to be fastened through the load transmitting member, and the material to be fastened is fastened using this axial force as a fastening force.

Here, a commercially available bolt can also be used for a bolt member, and it can also manufacture exclusively. As a material of the bolt member, any metal including general carbon steel, tool steel, stainless steel, alloy steel, and aluminum can be used, and a resin can be used when it does not have a large strength. Moreover, the external thread provided in the axial part of the bolt member can be provided in the whole axial part, and can also be provided in a partial region of the axial part. Moreover, the shape of the head part of a bolt member can use the shape of all bolt heads including a hexagon bolt and a hexagon socket head bolt, and can use all other shapes according to a use.
The head portion is composed of a lower surface to which the shaft portion is connected, an upper surface on the opposite side, and a side surface connecting the lower surface and the upper surface. Generally, the head portion is a lower surface to which the shaft portion is connected. It is designed to receive power. In this case, a structure in which one end of the elastic body and the lower surface of the head portion are in direct contact may be used, or a structure in which some article such as a plate or a washer exists between the elastic body and the lower surface of the head portion may be used.

  The load transmitting member has a surface that receives an axial force from the elastic body and a surface that transmits the axial force to the material to be fastened. The surface that receives the axial force from the elastic body may have a structure in which one end of the elastic body and this surface are in direct contact, and there are some articles such as plates and washers between the elastic body and this surface. It may be a structure. In addition, the surface that transmits the axial force to the material to be fastened may be in direct contact with the body of the material to be fastened, and there are some articles such as plates and washers between the body of the material to be fastened. Cases are also conceivable.

  The shape of the load transmitting member may be a flat plate shape having a surface that receives the axial force from the elastic body and a surface that transmits the axial force to the material to be fastened, as described above. It can have an arbitrary shape further including other parts. As a material of the load transmission member, any metal including general carbon steel, stainless steel, alloy steel, and aluminum can be used, and a resin can also be used when it does not have a large strength.

As the elastic body, for example, it is considered to use springs such as disc springs, coil springs, leaf springs, fluid springs using fluids including air springs, and elastic materials including rubber materials. It is done. As for the arrangement of the elastic body, it is only necessary to be arranged between the head portion and the load transmission member so as to be able to transmit the axial force to both, even when the elastic body is mounted on the shaft portion, This includes cases where it is not mounted.
When various springs are used as the elastic body, any metal including general carbon steel, spring steel, stainless steel, alloy steel, and aluminum can be used as the material.

  Regarding the frictional force applied by the restraining means, for example, even when the load transmission member is rotated, the bolt member rotates integrally with the load transmission member being constrained, and the male screw of the bolt member is fastened. It is desirable to have a frictional force that can be screwed into the female screw on the material side. That is, it is desirable to have a frictional force with such a magnitude that the constraint between the bolt member and the load transmitting member cannot be released by the resistance torque due to the friction between the screw threads. In the final tightening stage, if the bolt member is rotated with a wrench or the like while the load transmission member is stopped, the constraint between the bolt member and the load transmission member is released, and the bolt member is rotated. A frictional force that can be applied is desirable.

  As a restraining means for applying a frictional force in such a range, for example, it is conceivable to press an elastic material such as rubber against a bolt member and a load transmission member. It is also possible to make the force adjustable.

  In this embodiment, the elastic body can transmit the axial force to the head portion and the load transmitting member by the predetermined frictional force applied by the restraining means, and the axial force is not generated in the elastic body in the initial stage. Since the state can be maintained, the operator can perform the screwing operation of the fastening device while maintaining the initial state. Furthermore, by using a wrench or the like to give a rotational torque that overcomes this frictional force, the relative angle between the bolt member and the load transmission member can be rotated from the initial state to a predetermined angle. The material to be fastened can be tightened with a desired tightening force by compressing the elastic body by a corresponding screwing amount. Therefore, the axial force management of the bolt can be easily and accurately performed as compared with the conventional fastening operation using the torque wrench in which the axial force largely varies due to the variation of the friction coefficient of the thread.

  Also, since the deformation of the elastic body is larger than the elongation of the bolt alone, the rotation angle of the bolt member to obtain the required axial force can be increased, and the axial force management is much more accurate than before. It becomes possible. Similarly, a change in axial force caused by the influence of thermal expansion / contraction due to a temperature change can be greatly suppressed as compared with the conventional case.

  Furthermore, in the conventional fastening method using an elastic body, when there is a variation in the dimensions of the elastic body in the initial state in which no axial force is generated, an accurate axial force cannot be obtained. In the fastening device shown in this embodiment, an accurate axial force is always obtained by rotating the bolt member by a predetermined angle from the initial state regardless of the size of the elastic body in the initial state. Obtainable.

  In another embodiment of the fastening device of the present invention, the male screw is screwed into the female screw on the fastened material side while maintaining the initial state until the load transmitting member contacts the fastened material, After the load transmitting member comes into contact with the material to be fastened, the fastening force corresponding to the predetermined angle is further obtained by rotating only the bolt member by the predetermined angle and screwing it into the female screw on the material to be fastened. The material to be fastened is fastened with.

  Here, “the load transmission member abuts on the material to be fastened” includes the case where the load transmission member directly contacts the body of the material to be fastened, and between the load transmission member and the body of the material to be fastened. This includes cases where there are some items such as plates and washers.

  As described above, with the predetermined frictional force applied by the restraint means, the male screw of the fastening device can be screwed into the female screw on the material to be fastened while the initial state is maintained, and the attachment work can be performed. Then, after the load transmission member comes into contact with the material to be fastened, the load transmission member stops rotating due to the frictional force between the material to be fastened and the frictional force applied by the restraining means is applied using a wrench or the like. By providing a rotational torque that overcomes, only the bolt member can be rotated further.

  In this embodiment, the material to be fastened can be easily fastened with a desired axial force by rotating the bolt member using a wrench or the like, similarly to screwing a normal bolt.

  In another embodiment of the fastening device of the present invention, the load transmission member further includes a cover portion that covers the elastic body and the head portion.

Here, the aspect that “the cover part covers the head part” includes an aspect that covers the entire head part by the cover part, and an aspect that covers only a part thereof. As a mode of covering only a part, for example, it may be considered that the upper surface of the head portion is opened and a wrench for rotating the bolt member can be inserted.
In this embodiment, since the load transmission member includes the cover part and can cover the elastic body and the head part of the bolt member, for example, dirt, dust, oils and the like generated from the elastic body etc. leak to the outside. Can be prevented. Therefore, for example, the present invention can be applied even in an environment that requires strict pollution control, such as inside a clean room. Moreover, since the elastic body etc. cannot be seen from the outside by the cover part, the fastening device excellent in the design property of the very neat appearance can be provided.

  Another embodiment of the fastening device of the present invention further includes a sealing material for closing a gap between the head portion and the cover portion, and the sealing material functions as the restraining means. .

  In this embodiment, a high sealing performance can be obtained by the sealing material, and at the same time, an appropriate frictional force can be applied to the bolt member and the load transmission member by using the elasticity of the sealing material, so that the manufacturing cost can be reduced. In addition, a compact fastening device can be provided.

Another embodiment of the fastening device of the present invention is characterized in that the elastic body is constituted by a disc spring that is ring-mounted around the shaft portion.

  In this embodiment, by using a disc spring as the elastic body, a large axial force can be generated while having a small size.

  In another embodiment of the fastening device of the present invention, in order to visually recognize a relative rotation angle between the bolt member and the load transmission member, display means is provided on the bolt member and the load transmission member. It is characterized by that.

Here, as a display means for visually recognizing the rotation angle, for example, it is conceivable to mark a bolt member or a load transmission member, and as this marking, it is also possible to mark with a paint, engraving or cutting In addition, marking may be performed by machining such as grinding, or a tape or a sheet on which marking is described may be pasted.
In the present embodiment, the display means enables the operator to accurately grasp the rotation angle of the bolt member, so that accurate axial force can be easily managed.

  In another embodiment of the fastening device of the present invention, the display means includes a scale indicating a rotation angle provided on at least one of the bolt member or the load transmission member.

Like the above marking, the scale indicating the rotation angle may be provided by paint, or may be provided by stamping or machining by mechanical processing such as stamping or cutting and grinding. It is also possible to attach a sheet.
In this embodiment, by providing an angle scale that matches the range of the required tightening force, even in a fastening operation in which a plurality of axial forces are set, the operator can set the rotation angle of the bolt member to each axis. It can be easily adjusted to the rotation angle corresponding to the force, and each accurate axial force can be easily managed.

  One embodiment of the fastening method of the present invention is a bolt member provided with a shaft portion having a male screw and a head portion, and is attached to the shaft portion so as to be able to transmit a force in contact with a material to be fastened. An elastic body that is disposed between a load transmission member, the head portion, and the load transmission member, and that can transmit an axial force (axial force) of the bolt material to the head portion and the load transmission member. In order to visually recognize the relative rotation angle between the bolt member and the load transmission member, the restraining means that can restrain the relative movement of the bolt member and the load transmission member by a predetermined friction force, A fastening device comprising: a display device provided on the bolt member and the load transmission member; and a method of fastening the material to be fastened, wherein the bolt member and the load transmission member are provided with the fastening device. Step 1 of setting the display means to the corresponding position; Step 2 of restraining the bolt member and the load transmission member by the restraining means in an initial state in which the elastic body in which the axial force is not generated can transmit the axial force to the head portion and the load transmission member. And screwing the male screw into the female screw on the fastened material side while maintaining the initial state until the load transmitting member contacts the fastened material, and the load transmitting member is fastened to the fastened material After the contact with the material, further, only the bolt member is rotated by the predetermined angle, and the elastic body is compressed by the screwing amount corresponding to the predetermined angle, whereby the tightening force corresponding to the predetermined angle is obtained. And a step 4 of fastening the material to be fastened.

  According to this embodiment, as already described above, accurate axial force management can be performed very easily in the fastening operation of the material to be fastened.

  As described above, in the fastening device of the present invention and the fastening method using the fastening device, the bolt member is rotated by a predetermined rotation angle from the initial state, and an axial force corresponding to the rotation angle is generated in the elastic body. This makes it possible to easily manage the axial force of the bolt member more accurately than in the past.

  In addition, by using an elastic body with a large deformation amount compared to the bolt shaft, more accurate axial force management is achieved, and changes in axial force caused by thermal expansion / contraction due to temperature changes are It can be greatly suppressed compared to.

  Furthermore, in the fastening device of the present invention and the fastening method using the fastening device, even if the size of the elastic body in the initial state varies, by always controlling the rotation angle from the initial state of the bolt member, Accurate axial force management can be performed.

Embodiments of a fastening device and a fastening method using the fastening device of the present invention will be described below in detail with reference to the drawings.
(Description of Embodiment of Fastening Device of the Present Invention)
First, one embodiment of the fastening device of the present invention will be described with reference to FIG. Fig.1 (a) is a perspective view which shows the external shape of the fastening apparatus of this embodiment, FIG.1 (b) is sectional drawing seen from the arrow A of Fig.1 (a).

As shown in FIG. 1B, in the fastening device 1 of the present embodiment, the load transmission member 3 is mounted on the shaft portion 2 a of the bolt member 2, and the shaft portion 2 a is mounted on the load transmission member 3. The elastic member 4 (the assembly of the disc springs 4a) is disposed, and the axial force (axial force) of the bolt member 2 generated on the elastic member 4 by pressing the elastic member 4 is applied to the bolt member 2 and the load. It is structured to transmit to the transmission member 3.
The bolt member 2 of the present embodiment is a hexagon socket head cap bolt in which a cylindrical shaft portion 2a having a male screw 2c and a cylindrical head portion 2b are integrally formed. The head portion 2b includes: A recess 2d for inserting a hexagon wrench is provided. The load transmitting member 3 is integrally formed with a disk-shaped bottom 3a provided with an opening 3c and a cylindrical cover 3b that covers the disc spring 4 and the head 2b of the bolt member 2. It is configured. By inserting the body portion 2a of the bolt member 2 into the opening 3c of the bottom portion 3a, the load transmission member 3 is mounted on the shaft portion 2a. The cover 3b covers the elastic body 4 and the bottom surface 2b1 and the side surface 2b3 of the head portion 2b, but the top surface 2b2 of the head portion 2b is open, and a recess 2d provided on the open top surface 2b2. In addition, a hexagon wrench can be set.

  In the present embodiment, the elastic body 4 is mounted on the shaft portion 2a of the bolt member 2 in such a manner that two sets of disc springs 4a stacked one by one are opposed to each other. The elastic member 4 is disposed between the bottom 3a of the load transmitting member 3 and one end of the elastic body 4 is in contact with the lower surface 2b1 of the head 2b, and the other end is in contact with the inner surface 3a1 of the bottom 3a. Is transmitted to both members. A detailed study on the axial force generated by the elastic body 4 will be described later. Not only when the elastic body 4 and both members are in direct contact but also when there is a washer, a plate, etc. between the elastic body and both members, the same elastic force can be transmitted to both members. If it is, it can be regarded as being equivalent to being in contact. Further, the outer surface of the bottom portion 3a comes into contact with the material to be fastened, and the axial force received from the elastic body 4 is transmitted to the material to be fastened.

Next, a rubber O-ring 5 is disposed above the cover portion 3 b of the load transmission member 3, and the inner diameter side of the O-ring 5 comes into contact with the side surface 2 b 3 of the head portion 2 b of the bolt member 2. The outer diameter side is in contact with the inner wall 3b1 of the cover portion 3b of the load transmitting member 3 and covers the gap between the head portion 2b and the cover portion 3b. That is, when the fastening device 1 is attached to the material to be fastened, the disc spring 4a is sealed inside the load transmission member 3, so that dirt, dust, oils and the like from the disc spring 4a are removed from the fastening device. There is no fear of leaking out of 1, and for example, it can be applied to strict contamination control applications such as in a clean room.
The dimensions of each member are set so that the O-ring 5 contracts by a predetermined amount. The O-ring 5 covers the gap and simultaneously applies a frictional force between the head portion 2b and the cover portion 3b. , Both are restrained. That is, the O-ring 5 has both functions of a cover that covers a gap between the bolt member 2 and the load transmission member 3 and a function of restraining means that restrains the space between the bolt member 2 and the load transmission member 3. Have.

As shown in FIG. 1B, the region where the O-ring 5 above the inner wall 3b1 of the cover portion 3b of the load transmitting member 3 is inserted is machined to obtain dimensional accuracy and is slightly lower than below the inner wall 3b1. The inner diameter is large. Further, the region where the O-ring 5 of the inner wall 3b1 is inserted is not provided with a recess or the like for accommodating the O-ring 5, and the O-ring 5 can rotate and move in the axial direction. The bolt member 2 can be easily moved in the axial direction. Therefore, the bolt member 2 can be easily moved in the axial direction with respect to the load transmission member 3 by the force of a human finger.
On the other hand, since the O-ring 5 is press-fitted around the entire circumference between the side surface 2b3 of the head portion 2b and the inner wall 3b1 of the cover portion 3b, the restraining force in the rotational direction of the bolt member 2 is greater than that in the axial direction. Has a large binding force. Therefore, when the material to be fastened is fastened by screwing the male screw 2a of the bolt member 2 into the female screw on the material to be fastened, it is temporarily rotated by grasping not the bolt member 2 but the outer load transmitting member 3 Even if it is made to be, if it is the resistance torque of normal screw fitting, the bolt member 2 will rotate integrally in the state restrained by the load transmission member 3, and will be a screw like the case where the bolt member 2 is rotated. Can be included.

  However, the restraining torque in the rotational direction by the O-ring 5 is a friction torque based on the elastic force of rubber, and is smaller than the rotational torque using a wrench or the like. As will be described later, after the outer surface 3a2 of the bottom portion 3a of the load transmitting member 3 and the surface portion of the material to be fastened come into contact with each other, when the bolt member 2 is further rotated using a hexagon wrench, the outer surface 3a2 of the bottom portion 3a The rotation of the load transmitting member 3 is stopped by the frictional force with the surface portion of the material to be fastened, and only the bolt member 2 can be rotated.

  Further, in the present embodiment, as shown in FIG. 1A, in order to visually recognize the relative rotation angle between the bolt member 2 and the load transmission member 3, a display means 6 is provided on each member. Yes. Specifically, the marking 6 a is attached to the upper surface 2 b 2 of the head part 2 b of the bolt member 2, and the marking 6 b is attached to the upper part of the cover part 3 b of the load transmission member 3. Using these markings 6a and 6b, the angle between the bolt member 2 and the load transmission member 3 can be easily visually recognized and measured. In addition, about marking, it can also mark by a paint, for example, can also mark by machine processing, such as marking, cutting, and grinding, and can also use both together. It is also conceivable to attach a tape on which markings have been described in advance, and any other marking means can be used.

  As for the material of each member, the bolt member 2 can use any metal including general carbon steel, tool steel, stainless steel, alloy steel, and aluminum, and use resin when it does not have a large strength. You can also. In the load transmission member 3, any metal including general carbon steel, stainless steel, alloy steel, and aluminum can be used, and a resin can also be used when it does not have a large strength. The structure of the load transmission member 3 may be an integrally molded product by machining, extrusion, casting, or the like, or an assembly in which the bottom 3a and the cover 3b are connected by welding, screwing, or the like can be used. . Similarly, the bolt member 2 may be an integrally molded product or an assembled product.

  The disc spring 4a can be made of any metal material such as general carbon steel, tool steel, stainless steel, and alloy steel. A commercially available product or a custom-made product produced exclusively for the disc spring 4a can be used. The O-ring 5 can use any rubber material including nitrile rubber. For example, fluorine rubber can be used when used in a solvent atmosphere, and heat resistant rubber can also be used when used in a high temperature non-atmosphere.

As described above, since the fastening device of the present embodiment is configured with commercially available parts and members that are easy to manufacture, manufacturing is easy and manufacturing costs can be kept low. Also, since the disc springs etc. are sealed inside the fastening device, dirt etc. from the disc springs etc. can be sealed inside the fastening device, so it is suitable for applications in environments with strict pollution control such as clean rooms, It is also excellent in design that disc springs are not visible from the outside.

(Description of Embodiment of Fastening Method Using Fastening Device of the Present Invention)
Next, an embodiment of a fastening method for fastening a material to be fastened by the fastening device 1 shown in FIG. 1 will be described with reference to FIG. 2A shows a state before the fastening device 1 is attached to the material to be fastened 10, and FIG. 2B shows that the fastening device 1 is rotated in a state where the bolt member 2 and the load transmission member 3 are constrained. FIG. 2 (c) shows a place where only the bolt member 2 is rotated and screwed. In addition, the left figure of Fig.2 (a) is a perspective view which shows the external shape of the fastening apparatus 1, and the right figure is side sectional drawing seen from the arrow A of the left figure. FIGS. 2B and 2C are also side sectional views as seen from the same position as in the right view of FIG.

  First, as shown to Fig.2 (a), the display means 6 provided in the bolt member 2 and the load transmission member 3 is set to a corresponding position. Specifically, the bolt member 2 and the load transmission member 3 are relatively rotated, and the marking 6a provided on the head portion 2b of the bolt member 2 and the marking provided on the cover portion 6b of the load transmission member 6b. The positions of 6b are matched. In this case, the bolt member 2 and the load transmission member 3 can be relatively rotated by grasping the body 2a of the bolt member 2 and the cover 3b of the load transmission member 3 with fingers.

Next, while maintaining the positions of the markings 6a and 6b set as described above, the upper surface 2b2 of the head portion 2b of the bolt member 2 is lightly pressed with a finger so that the lower surface 2b1 of the head portion 2b and the upper end of the elastic body 4 come into contact with each other. The bolt member 2 is pushed into the load transmitting member 3 until the lower end of the elastic body 4 and the inner surface 3a1 of the bottom 3a of the load transmitting member 3 come into contact with each other. As described above, since the restraining force in the axial direction of the bolt member 2 by the O-ring 5 is small, the bolt member 2 can be pushed into the load transmitting member 3 with a relatively small force, and the elastic body 4 can be pushed by this pushing force. There is no possibility that the shaft will deform and substantially generate an axial force.
As described above, the display means 6 provided on the bolt member 2 and the load transmission member 3 are set to the corresponding positions, and the elastic body 4 is placed on the lower surface 2b1 of the head portion 2b in a state where no axial force is generated. FIG. 2 shows a state in which the bolt member 2 and the load transmission member 3 are restrained by the O-ring 5 in an initial state in which the bolt member 2 and the inner surface 3a1 of the bottom 3a of the load transmission member 3 are in contact with each other (that is, capable of transmitting axial force). Shown in (a).

Next, as shown in FIG. 2B, the shaft portion 2a of the bolt member 2 is inserted into the bolt hole 11 of the upper material to be fastened 10a while the fastening device 1 is maintained in the above state. Then, the hexagon wrench 20 is set in the recessed portion 2d provided in the head portion 2b of the bolt member 2, the entire fastening device 1 is rotated, and the male screw 2c of the bolt member 2 is connected to the lower material to be fastened 10b. Screw into the screw hole 12. In this case, the bolt member 2 and the load transmission member 3 are rotated integrally with the restraining force of the O-ring 5. That is, screwing is performed while maintaining the positions of the matching markings 6a and 6b as they are.
Not only the method of rotating and screwing the bolt member 2 using the hexagon wrench 20, but also the outer load transmitting member 3 can be rotated and screwed. In this case, if the screw engagement is normal, the restraint torque by the O-ring 5 is larger than the resistance torque due to the frictional resistance of the screw, so that the bolt member 2 and the load transmission member 3 are integrally restrained. Rotate.

  If the screwing is further continued, then, as shown in FIG. 2C, the outer surface 3a2 of the bottom 3a of the load transmitting member 3 comes into contact with the upper surface 10a1 of the material to be fastened 10a. In this state, when the bolt portion 2 is further rotated using the hexagon wrench 20, the rotation of the load transmitting member 3 is stopped by the frictional force between the outer surface 3a1 of the bottom portion 3a and the upper surface 10a1 of the material to be fastened 10a. If the load transmitting member 3 is further rotated, the surface pressure between the outer surface 3a2 of the bottom 3a of the load transmitting member 3 and the upper surface 10a1 of the material to be fastened 10a is increased and the frictional force is increased, so that the rotation is prevented. The That is, it becomes a so-called self-lock state. Considering the coefficient of friction between normal metal surfaces, it is considered that the possibility that the material to be fastened 10a rotates even after contacting the load transmitting member 3 is low. It is also conceivable to increase the coefficient of friction by providing unevenness or coating on the outer surface 3a2 of the bottom 3a. Even if the material to be fastened 10a rotates even after contacting the load transmission member 3, the display means 6 provided on the bolt member 2 and the load transmission member 3 causes the relative state from the initial state of both members. As the correct rotation angle can be accurately grasped, no problem occurs.

  As described above, with the rotation of the load transmission member 3 stopped, only the bolt member 2 is further rotated, and the male screw 2c of the bolt member 2 is continuously screwed into the screw hole 12 of the material to be fastened 10b. Go. That is, from the initial state in which the marking 6a and the marking 6b coincide with each other, the bolt member 2 rotates relative to the load transmission member 3, and the lower surface 2b1 of the head portion 2b and the inner surface 3a1 of the bottom portion 3a of the load transmission member 3 Is shortened by a length X (specifically, X = screw pitch × rotation angle / 360 degrees) corresponding to the relative rotation angle. As a result, an axial force F corresponding to the deformation amount X is generated in the elastic body 4 composed of the disc spring 4a. If the disc spring 4a has a linear characteristic, an axial force F proportional to the deformation amount X (specifically, F = kX, k: spring constant) is generated. That is, the elastic body 4 generates an axial force proportional to the rotation angle of the bolt member 2 with respect to the load transmission member 3. Even when a disc spring having no linear characteristics is used, the axial force F corresponding to the deformation amount X can be reproduced if the compression amount has reproducibility.

  Therefore, as described above, a desired axial force is generated in the elastic body 4 by rotating the bolt member 2 until the angle between the marking 6a and the marking 6b matched in the initial state becomes a predetermined angle. Can be made. The relationship between the rotation angle between the marking 6a and the marking 6b and the axial force will be described in detail below.

  As described above, the operator can perform the screwing operation of the fastening device 1 while maintaining the initial state, and further, after the load transmission member 3 comes into contact with the material to be fastened and the rotation stops, the bolt member By rotating only 2, the relative angle between the bolt member 2 and the load transmission member 3 can be rotated from the initial state to a predetermined angle, and the elastic body 4 by the screwing amount corresponding to this angle. And the material to be fastened can be tightened with a desired tightening force. Therefore, it is possible to easily and accurately manage the axial force of the bolt as compared with the fastening operation using the torque wrench in which the axial force varies due to the variation of the friction coefficient of the thread.

  Further, since the deformation amount of the elastic body 4 is larger than the elongation of the bolt alone, the rotation angle of the bolt member 2 for obtaining the required axial force can be increased, and a very accurate shaft can be obtained compared to the conventional case. Force management becomes possible. Similarly, a change in axial force caused by the influence of thermal expansion / contraction due to a temperature change can be greatly suppressed as compared with the conventional case.

  Further, in the conventional fastening method using the axial force by the elastic body, when there is a variation in the dimensions of the elastic body in the initial state where the axial force is not generated, an accurate axial force cannot be obtained. The problem that the axial force varies depending on the elastic body has occurred, but in this embodiment, the bolt member 2 is always accurately rotated by rotating the bolt member 2 by a predetermined angle from the initial state regardless of the dimensions of the elastic body 4 in the initial state. Axial force can be obtained.

(Other embodiments of display means)
In the embodiment shown in FIGS. 1 and 2, the bolt member 2 and the load transmitting member 3 are each provided with one marking 6 a and 6 b, but in the embodiment shown in FIG. One marking 6a is provided, and the load transmission member 3 is provided with a scale 6b. If this embodiment is used, the bolt member 2 can be accurately adjusted to various rotation angles without using a measuring instrument or a jig. Therefore, even in a fastening operation in which a plurality of axial forces are set, the operator can easily grasp the rotation angle corresponding to each axial force by the angle scale, and each axial force can be easily obtained. Can be managed accurately.
Further, when the size and combination of the disc springs to be used are determined in advance, it may be possible to display a specific axial force value (for example, 50 kgf, 100 kgf, etc.) on the scale 6b.

In the embodiment shown in FIG. 3B, a rotation angle limiting means 7 for limiting the relative rotation angle between the bolt member 2 and the load transmission member 3 within a predetermined range is provided. The rotation angle limiting means 7 has a protrusion 7a attached to the side surface 2b3 of the head portion 2b and a notch 7b provided on the upper portion of the load transmission member 3 corresponding to the set angle. It is conceivable that the protrusion 7a is attached to the head 3b by, for example, an insertion method or a screw-in method.
In the present embodiment, the bolt member 2 can rotate only in the range from the position where the protrusion 7a is in contact with the end surface 8a of the notch 7b to the position where it is in contact with the end surface 8b. Therefore, it is possible to prevent a problem that an excessive axial force is generated due to a wrong rotation angle of the bolt member 2. For example, even an operator with little experience can perform a fastening operation without any problem.

(Explanation of relationship between rotation angle and axial force)
Next, the relationship between the relative angle between the bolt member 2 and the load transmission member 3 and the axial force generated by the elastic body 4 in the fastening device shown in FIG. 1 will be described. In the following examination, since the deformation of the material to be fastened is extremely small, the calculation is made on the assumption that there is no deformation.
<Calculation of axial force F>
The bolt member 2 shown in FIG. 1, assuming that the stainless steel bolts size M6, the effective cross-sectional area As of the screws M6 is a 20.1 mm ^2, yield strength W of Sutensu steel, at 240 N / mm ² is there. Here, when generating an axial force F of 60% of the proof stress of the stainless steel bolt,
Axial force F = As × W × 60% = 2894 N
It becomes.

<Calculation of deformation amount for disc spring>
Assuming that a 6 mm shaft heavy load disc spring JIS B2706H12.5 is used as the disc spring 4a shown in FIG. 1, the effective height of one sheet is 0.3 mm, and its load at 75% deformation is 693N. It is. Therefore, the spring constant k of the disc spring 4a near 75% deformation is
k = 693 / (0.3 × 75%) = 3080 N / mm
It is. The disc spring 4a used here has a substantially linear characteristic because the total deflection / plate pressure is 0.4.
Accordingly, as shown in FIG. 1 (b), in the elastic body 4 constituted by opposing two sets of five disc springs 4a stacked, the elasticity when the axial force F (2894N) is generated is generated. The total deformation amount S of the body 4 is
S = F / (5 × k) × 2 = 0.3758 mm
It is.

<Calculation of bolt member elongation>
On the other hand, the elongation of the bolt member 2 due to the axial force F is considered. The length L from the lower surface 2b1 of the head portion 2a of the bolt member 2 to the male screw 2c is 30 mm, the thickness of the material to be fastened 10a is 30 mm, and the total thickness is 10 mm for 10 disc springs 4a.
L = 30mm + 7mm = 37mm
It becomes.
Further, the elongation when the axial force F is applied to the length L portion of the bolt member 2 is λ, the longitudinal elastic modulus E of the stainless steel is 1.90 × 10 ⁵ N / mm ² ,
λ = F × L / (As × E) = 0.028 mm
It becomes.

<Calculation of rotation angle>
Based on the above, the rotation angle θ from the initial state of the bolt member 2 with respect to the load transmission member 3 when the axial force F is generated is calculated. Here, when the pitch p of the male screw 2c of the bolt member 2 is 1 mm,
θ = 360 × (S + λ) / p = 145 degrees.
Therefore, when the axial force F is proportional to the rotation angle θ, the proportional constant k _θ is
_k θ becomes = 2894/145 = 20.0 N / degree.
Using this relationship, the rotation angle at which the desired axial force F is generated can be calculated. Further, in the embodiment shown in FIG. 3 (a), it may also be provided graduations reflecting the proportionality constant k _theta. Further, for example, the Nii if a set of repeated five disc springs 4a of the elastic body 4 consists of only one set, the value of k _theta is twice the above value, it is 39.9N / degree, An axial force F = 2894N is generated at a rotation angle of 72.5 degrees.

<Rotation calculation when using only conventional bolts>
On the other hand, when only the bolt is used as in the conventional case, if the corresponding length L of the bolt 2 is 30 mm, the elongation λ is
λ = F × L / (As × E) = 0.023 mm
It becomes.
Therefore, the rotation angle θ of the bolt is
θ = 360 × λ / p = 8.3 degrees.

<Rotational torque when only conventional bolts are used>
Next, let us consider a case where the axial force is managed by managing the tightening torque by the torque wrench in the conventional fastening using only the bolt.
When the torque coefficient is kt and the bolt diameter d = 6 mm, the tightening torque T is Tightening torque T = kt × F × d = 17.4 × kt Nmm
It becomes. However, a value of about 0.2 may be used for the torque coefficient kt, but the actual value varies greatly depending on the condition of the thread surface, the dry state, the lubrication state, and the like. Therefore, accurate axial force management is difficult with this method of managing a greatly varying tightening torque.

  As described above, in the fastening device according to the present invention, the rotation angle of the bolt is made extremely large (for example, 145 degrees / 8.3 degrees) compared to the case where the axial force is obtained using only the elongation of the conventional bolt. = About 17.5 times), it was proved that an accurate axial force can be obtained very easily. Similarly, it was proved that an accurate axial force can be obtained without being affected by fluctuations in the tightening torque depending on the screw condition.

(Description of Example of Fastening Device of the Present Invention)
Next, an embodiment in which the fastening device of the present invention is applied to the assembly of a die head of a slit coater will be described with reference to FIG. Here, FIG. 4A is a plan view showing an outline of the outer shape of the die head, and FIGS. 4B and 4C are side sectional views as seen from the arrow B in FIG. FIG. 4B shows a structure assembled using conventional bolts, and FIG. 4C shows a structure assembled using the fastening device of the present invention. The fastening device 1 shown in FIG. 4 (c) has the same structure as the fastening device of the embodiment shown in FIG.

  First, the structure of a die head assembled using conventional bolts will be described with reference to FIGS. 4 (a) and 4 (b). The die head 30 inserts a shim 32 between a head main body 30a provided with a bolt hole and a head main body 30b provided with a screw hole, and fastens the head main body 30a and the head main body 30b using a bolt 50. Assembled by. The main dimensions of this die head are generally that the die head length L is in the range of 400 mm to 2000 mm or more, and the slit width t determined by the thickness of the shim to be inserted is in the range of 20 μm to 100 μm or more. Since the value of the slit width t is very small, when the bolt tightening force is not uniform, the slit width t varies, causing a problem of preventing uniform coating.

In order to obtain a uniform tightening force, the bolt pitch should be reduced as much as possible. However, as the number of bolts to be attached increases, it becomes difficult to manage the axial force of the bolts to be tightened. The mounting pitch may be 50 mm or more.
In the bolt installation, the torque of the bolt is managed by using a torque wrench to manage the axial force of the bolt. However, as described above, the bolt tightening torque varies greatly depending on the condition of the screw surface, the dry state, the lubrication state, etc. Even if the tightening torque of all the mounting bolts is made constant, the shaft of each bolt The force can vary considerably, which can cause the slit width t not to be within acceptable limits and prevent uniform coating. Therefore, in the assembly using the conventional bolt, since the axial force of the bolt changes in the tightening order, it is necessary to repeat the tightening many times in order to finally keep the slit width t within the allowable limit.
In addition, when the first tightening is performed and when the screw is once tightened and then tightened again, the coefficient of friction between the thread ridges changes, making it difficult to reproduce the same axial force. Further, since the axial force is obtained only by the extension of the bolt shaft, there is a problem that it is greatly affected by the thermal expansion / contraction due to the temperature change.

On the other hand, when the die head 30 is assembled using the fastening device 1 of the present invention as shown in FIG. 4C, the bolt member 2 is rotated by a predetermined angle with respect to the load transmission member 3 to accurately The axial force of the bolt can be easily obtained. Therefore, even if the number of fastening devices is large, the axial force can be easily managed, so that the fastening devices can be attached with an ideal bolt pitch. For example, the bolt pitch can be 20 mm. In this case, if the die head length L exceeds 2000 mm, more than 100 fastening devices can be attached, but the axial force of each fastening device can be easily achieved. Therefore, the burden of assembly work can be reduced compared to the conventional method.
Moreover, even when loosening once and tightening again, the same axial force as at the time of the first tightening can be easily reproduced. Further, since the axial force is obtained by the deformation of the elastic body, the influence of the axial force can be minimized even if it undergoes some thermal expansion / contraction due to temperature change.

  Furthermore, in this embodiment, since the elastic body 4 composed of the disc spring 4a is completely covered inside the fastening device 1, dirt, dust, oil and the like from the disc spring 4a may leak to the outside. Even if it is applied to a device used in a clean room such as a die head, there is no possibility of causing a problem of contaminating the product. As described above, the fastening device of the present invention has a structure that is very suitable for use in a clean room. Further, since the elastic body 4 and the like are not exposed to the outside, it has a very clean appearance and is excellent in design.

(Description of Other Embodiments of Fastening Device of the Present Invention)
Next, other embodiments of the fastening device of the present invention will be described with reference to FIGS. 5 and 6. First, the embodiment shown in FIG. 5 will be described. FIG. 5 (a) is a perspective view showing the overall outer shape of the fastening device, and FIG. 5 (b) is seen from the arrow A in FIG. 5 (a). It is side surface sectional drawing.

In the present embodiment, the elastic body 4 composed of the disc spring 4 a has the most basic structure that is not covered by the load transmission member 3. The load transmission member 3 has a flat plate shape having an opening 3c, and is mounted on the shaft portion 2a of the bolt member 2 through the opening 3c. In addition, an O-ring 5 is attached to the opening 3c between the shaft portion 2 and the load transmission member 3, and functions as a restraining means. Further, as shown in FIG. 5A, the head portion 2b of the bolt member 2 and the load transmission member 3 are provided with display means (marking) for visually recognizing the rotation angle.
As described above, the present embodiment is suitable for use in a situation where pollution control or the like is not relatively strict, and has an advantage of reducing the manufacturing cost.

  Next, the embodiment shown in FIG. 6 will be described. FIG. 6 is a side sectional view corresponding to FIG. In the present embodiment, a plurality of coil springs 4a are used as the elastic body 4, and the coil springs 4a are arranged around the shaft portion 2a. Moreover, the head part 2b of the bolt member 2 has a head shape of a hexagonal bolt instead of a head shape of a hexagon socket head cap screw. Further, a plate 3 'exists between the coil spring 4a and the head portion 2b. In the present embodiment, generally, the tightening force cannot be as great as a disc spring, but on the other hand, even if the axial variation of the bolt member is large, the variation of the axial force can be suppressed.

  The fastening device and the fastening method using the fastening device of the present invention include not only the above-described embodiments but also various other embodiments.

It is the perspective view and side sectional drawing which show one Embodiment of the fastening apparatus of this invention. It is the perspective view and side sectional drawing which show one Embodiment of the fastening method using the fastening apparatus of this invention. It is a perspective view which shows the other embodiment of the fastening apparatus of this invention, especially another display means. It is the top view and side sectional view showing the structure of the die head using the fastening device of the present invention. It is the perspective view and side sectional drawing which show other embodiment of the fastening apparatus of this invention. It is side surface sectional drawing which shows other embodiment of the fastening apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fastening device 2 Bolt member 2a Shaft part 2b Head part 2b1 Lower surface 2b2 Upper surface 2b3 Side surface 2c Male screw 2d Recessed part 3 Load transmission member 3a Bottom part 3a1 Inner surface 3a2 Outer surface 3b Cover part 3b1 Inner wall 3c Opening 3 'Plate 4 Elastic body 4a Disc spring , Coil spring 5 O-ring 6 display means 6a marking 6b marking 7 rotation angle limiting means 7a protrusion 7b notch 8a end 8b end 10a material to be fastened 10b material to be fastened 11 bolt hole 12 screw hole 20 hexagon wrench 30 die head 30a head body 30b head body 32 shim 50 bolt

Claims (8)

A bolt member including a shaft portion having a male screw and a head portion;
A load transmitting member that is mounted on the shaft portion and capable of transmitting a force to the material to be fastened;
An elastic body that is disposed between the head portion and the load transmission member and capable of transmitting axial force (axial force) of the bolt material to the head portion and the load transmission member;
Restraining relative movement between the bolt member and the load transmission member by a predetermined frictional force, the elastic body is capable of transmitting the axial force to the head portion and the load transmission member; And a restraining means capable of maintaining an initial state in which the axial force is not generated in the elastic body,
With
A tightening force corresponding to the predetermined angle is obtained by rotating the bolt member by a predetermined angle from the initial state with respect to the load transmitting member and compressing the elastic body by a screwing amount corresponding to the predetermined angle. A fastening device for fastening the material to be fastened with. Until the load transmission member contacts the material to be fastened, the male screw is screwed into the female screw on the material to be fastened while maintaining the initial state,
After the load transmission member comes into contact with the material to be fastened, further tightening corresponding to the predetermined angle by rotating only the bolt member by the predetermined angle and screwing into the female screw on the material to be fastened. The fastening device according to claim 1, wherein the fastening material is fastened by force.   The fastening device according to claim 1, wherein the load transmission member further includes a cover portion that covers the elastic body and the head portion.   The fastening device according to claim 3, further comprising a sealing material for closing a gap between the head portion and the cover portion, wherein the sealing material functions as the restraining means.   The fastening device according to any one of claims 1 to 4, wherein the elastic body is configured by a disc spring provided around the shaft portion.   6. The display device according to claim 1, wherein display means is provided on the bolt member and the load transmission member in order to visually recognize a relative rotation angle between the bolt member and the load transmission member. The fastening apparatus of Claim 1.   The fastening device according to claim 6, wherein the display means includes a scale indicating a rotation angle provided on at least one of the bolt member or the load transmission member. A bolt member provided with a shaft portion having a male screw and a head portion, a load transmission member that is mounted on the shaft portion and is capable of transmitting a force in contact with a material to be fastened, the head portion, and the load transmission An elastic body that is disposed between the head member and the load transmitting member and capable of transmitting an axial force (axial force) of the bolt material to the head portion and the load transmitting member; In order to visually recognize the relative rotation angle between the bolt member and the load transmission member and the restraining means capable of restraining relative movement with the load transmission member, the bolt member and the load transmission member are provided. A fastening means comprising a fastening device comprising a display means,
Setting the display means provided on the bolt member and the load transmission member at a corresponding position;
Step 2 of restraining the bolt member and the load transmission member by the restraining means in an initial state in which the elastic body in which the axial force is not generated can transmit the axial force to the head portion and the load transmission member. When,
Step 3 of screwing the male screw into the female screw on the fastened material side while maintaining the initial state until the load transmitting member contacts the fastened material;
After the load transmitting member comes into contact with the material to be fastened, further, by rotating only the bolt member by the predetermined angle and compressing the elastic body by a screwing amount corresponding to the predetermined angle, Step 4 of fastening the material to be fastened with a fastening force corresponding to a predetermined angle;
The fastening method characterized by including.

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