JP2011075085A - Bolt coming-off prevention structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bolt coming-off prevention structure capable of preventing coming-off of the bolt certainly and facilitating to attach and detach the bolt. <P>SOLUTION: The coming-off prevention structure for the bolt 16 that fastens a rotating object guard 7 to a stay 13 includes a washer 19 unseparably mounted onto a non-screw shaft portion 18b of the bolt 16; a cover member 24 having a ceiling plate portion 24a opposed to the washer 19; and an opening 25 formed in the ceiling plate portion 24a of the cover member 24. The structure is configured to enable switching between a bolt attachable/detachable position to permit passage of the washer 19 through the opening 25, and a bolt unattachable/undetachable position not to permit the passage of the washer 19 through the opening 25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bolt fall-off prevention structure for fastening a member to be attached to an attachment member.

  In general, an air conditioner compressor, an alternator, and the like that are driven to rotate using the rotational power of the engine are disposed around the engine. For example, in an air conditioner compressor, a rotating object guard is mounted so as to cover the rotating part in order to prevent the rotating part from being inadvertently contacted. Since this rotating object guard may be removed for maintenance or inspection, it is fixed by bolt fastening means that can be easily attached and detached.

  When removing the rotating object guard for maintenance or inspection, an operation of loosening the bolts fixing the rotating object guard is performed. At this time, the loosened bolt may be dropped and lost. Due to the loss of the bolt, there is a risk of leaving the rotating object guard unattached. In order to prevent such a situation from occurring, it is necessary to prevent the bolt from falling off the rotating object guard (attached member).

  Conventionally, there is a screw drop prevention mechanism disclosed in Patent Document 1, for example, as a technique for preventing bolt drop-off from a mounted member.

Japanese Utility Model Publication No. 63-15319

As shown in FIGS. 9A and 9B, the screw drop prevention mechanism according to Patent Document 1 is fixed by a screw 101 (hereinafter referred to as “sems screw 101”) in which the washer 100 is incorporated so as not to be separated. This is applied to a fastening structure for fastening 102 and a fixed plate 103, and includes a sems screw holding metal fitting 104 having a protrusion 104 a including the head side of the sems screw 101.
The Sems screw holding metal fitting 104 is fixed to the fixing plate 102 by tightening the metal fitting attaching screw 105. A round hole 106 that is larger than the head of the Sems screw 101 and smaller than the washer 100 is formed in the protrusion 104 a of the Sems screw holding metal fitting 104. Through this round hole 106, the tool can be fitted into the head of the sems screw 101 to loosen or tighten the sems screw 101. When the sems screw 101 is not fastened, it is possible to prevent the sems screw 101 from falling off the fixing plate 102 by bringing the washer 100 into contact with the edge of the round hole 106.

  By the way, when the thread of the sems screw 101 is crushed, the sems screw 101 needs to be replaced. The replacement work of the sems screw 101 is performed as follows. First, the fitting screw 105 is loosened and the Sems screw holding fitting 104 is removed from the fixing plate 102. Next, the old sems screw 101 that needs to be replaced is removed from the fixing plate 102. Next, a new Sems screw 101 is assembled into the fixing plate 102. Then, the Sems screw holding metal fitting 104 is positioned at a predetermined position with respect to the fixing plate 102, and the Sems screw holding metal fitting 104 is fixed to the fixing plate 102 by tightening the metal fitting attaching screw 105.

However, the screw drop prevention mechanism according to Patent Document 1 involves the problem that the attachment and detachment work of the sems screw holding metal fitting 104 is accompanied when the sems screw 101 is attached and detached, and therefore the detachment work of the sems screw 101 cannot be easily performed. is there.
Needless to say, the same problem arises when the above-described screw drop-off prevention mechanism is applied to a fastening structure in which the attached member and the attachment counterpart member are fastened by bolts.

  The present invention has been made in view of the above-described problems, and provides a bolt fall-off prevention structure that can easily remove or attach a bolt, as well as the bolt fall-off. It is intended to do.

In order to achieve the above object, the bolt fall-off prevention structure according to the present invention comprises:
A bolt fall-off prevention structure for fastening a member to be attached to a member to be attached,
A washer that is attached to the shaft portion of the bolt inseparably and is configured to be rotatable around the shaft portion;
A cover member having a plate portion facing the washer;
An opening formed in the plate portion of the cover member,
A bolt detachable position where the washer can pass with respect to the opening and a bolt detachable position where the washer cannot pass with respect to the opening according to the rotation angle of the washer about the shaft portion of the bolt. It is characterized by having (1st invention).

  In this invention, it is preferable that the said washer is a shape which has a notch in at least one place of the outer peripheral part (2nd invention).

In this invention, it is preferable that the said washer is a shape which has a protrusion in at least one place of the outer peripheral surface (3rd invention).

  In the present invention, it is preferable that the washer is mounted in an eccentric state with respect to the shaft portion of the bolt (fourth invention).

According to the present invention, when the bolt is about to come off from the attached member when the washer cannot pass through the opening of the cover member, the washer is caught on the cover member and the bolt is removed. Directional movement is stopped. Thereby, it can prevent that a volt | bolt falls off from a to-be-attached member.
In addition, when the bolt is in a detachable position where the washer can pass through the opening of the cover member, the bolt can be inserted into and removed from the attached member through the opening of the cover member. Thereby, attachment / detachment of a bolt can be performed easily.

The perspective view explaining the general | schematic structure of the periphery of the air-conditioning compressor equipped with the rotating body guard to which the bolt drop-off prevention structure according to one embodiment of the present invention is applied. Enlarged perspective view of the rotating object guard seen from the bolt fastening part side The state of the bolt non-detachable position in the view of arrow A in FIG. 2 (a) and the state of bolt fastening in the cross-sectional view taken along the line B-O-B in (a) (b) 2A is a state diagram of a position where a bolt is not attachable and detachable, and FIG. 2B is a sectional view taken along the line B-O-B of FIG. 2A is a state diagram of the bolt detachable position in the arrow A view of FIG. 2, and a bolt non-fastened state diagram of the cross section taken along the line B-O-B of FIG. 2A. Illustration of washer notch shape and position The figure which illustrates the combination of the shape of a washer and the shape of the opening of a cover member It is explanatory drawing of the modified example of the fall-off prevention structure of a volt | bolt, A bolt fastening state figure (b) with the BB line sectional drawing of a top view (a) and (a) of a volt | bolt non-detachable position state It is explanatory drawing of a prior art, and is principal part sectional drawing of a fastening part (a) and X arrow directional view (b) of (a)

  Next, specific embodiments of the bolt drop-off preventing structure according to the present invention will be described with reference to the drawings. In the following, an example in which the present invention is applied to a fastening bolt for a rotating object guard attached to an air conditioner compressor will be described. However, the present invention is not limited to this example. For example, an alternator, a cooling fan, a power train, etc. The present invention can also be applied to a fastening bolt for a protector attached around the periphery.

<Description of air conditioner compressor>
As shown in FIG. 1, the air conditioner compressor 1 is attached to the engine 3 via a bracket 2. A driven pulley 4 is fixed to the rotating shaft of the air conditioner compressor 1. A drive pulley 5 is supported on the engine 3. A transmission belt 6 is wound around the driven pulley 4 and the drive pulley 5. A part of the rotational power of the engine 3 is transmitted from the driving pulley 5 to the air conditioner compressor 1 through the transmission belt 6 and the driven pulley 4. Thereby, the air-conditioner compressor 1 is rotationally driven and the refrigerant can be compressed.

<Description of rotating object guard (1)>
The air conditioner compressor 1 is provided with a rotating object guard 7 that covers the upper portion of the driven pulley 4. In this way, it is possible to reliably prevent unexpected contact with the driven pulley 4 that is the rotating part during maintenance and inspection.
1 is an alternator, and what is indicated by “9” in FIG. 1 is a rotating object guard that covers a driven pulley 10 that is a rotating part of the alternator 8. It is.

<Description of rotating object guard (2)>
As shown in FIG. 2, the rotating object guard 7 attached to the air conditioner compressor 1 is a sheet metal structure mainly formed by combining an upper sheet metal 11 and a side sheet metal 12. The rotating object guard 7 is supported by a stay 13 extending from the bracket 2 in the vicinity of the driven pulley 4. The upper metal plate 11 of the rotating object guard 7 includes a curved portion 11 a that is bent in an arc shape according to the outer peripheral shape of the driven pulley 4, and a flat portion 11 b that is superimposed on the upper surface of the stay 13.

<Description of rotating object guard (3)>
As shown in FIG. 3B, a bolt insertion hole 14 is formed in the flat portion 11 b of the upper metal plate 11. A screw hole 15 corresponding to the bolt insertion hole 14 is formed in the stay 13. The rotating object guard 7 is fixed to the stay 13 by tightening a bolt 16 that is screwed into the screw hole 15 through the bolt insertion hole 14.

<Description of bolt>
The bolt 16 is a hexagon socket head bolt, and includes a columnar head portion 17 in which a hexagon hole is formed, and a shaft portion 18 extending coaxially from the center portion of the head portion 17. Yes. The shaft portion 18 includes a screw shaft portion 18a which is a portion where a screw having a predetermined length is cut on the distal end side, and a non-screw shaft portion 18b which is a portion where the screw is not cut on the proximal end side. . The outer diameter dimension of the non-screw shaft portion 18b is smaller than the outer diameter size of the screw shaft portion 18a.
In addition, when the shaft portion 18 of the bolt 16 is in a state in which a washer 19 described later hits an edge of an opening 25 of the cover member 24 described later, the tip of the shaft portion 18 is pulled out from the bolt insertion hole 14 of the flat portion 11b. There is no length dimension (see FIG. 4B). Thus, since the tip of the shaft portion 18 does not come out of the bolt insertion hole 14, the trouble of positioning the bolt 16 with respect to the bolt insertion hole 14 at the time of reassembly can be saved.

<Description of washer>
A washer 19 is attached to the non-screw shaft portion 18b of the bolt 16 so as not to be separated. The washer 19 is a flat washer that is concentric with the center O of the bolt 16 and is configured to be rotatable about the non-screw shaft portion 18b.
The inner diameter of the washer 19 is slightly larger than the outer diameter of the non-screw shaft portion 18b and smaller than the outer diameter of the screw shaft portion 18a. The outer diameter of the washer 19 is larger than the outer diameter of the head 17 of the bolt 16.

<Description of the shape position of the washer notch>
As shown in FIG. 6, xy orthogonal coordinates are determined based on the center of the washer 19 (center O of the bolt 16).
The outer periphery of the washer 19 has a position on the positive y-axis, a position of 135 ° clockwise with respect to the positive y-axis, and a position of 135 ° counterclockwise with respect to the positive y-axis. Each arc-shaped notch 20 is formed.
The washer 19 is shaped to be line symmetric with respect to the y axis as the axis of symmetry.
The “outer peripheral portion of the washer 19” means a circumference required for stably seating the head portion 17 of the bolt 16 on the flat portion 11b of the upper metal plate 11 and obtaining a predetermined surface pressure. It is a portion outside the region 21.

<Description of bolt assembly>
Note that the bolt assembly 22 in which the washer 19 is attached to the bolt 16 so as not to be separated is the same as a so-called “washer built-in bolt (sems bolt)”.

<Description of mounting method of washer to bolt>
As shown in FIG. 3B, as a method of mounting the washer 19 inseparably on the non-screw shaft portion 18b between the head portion 17 of the bolt 16 and the screw shaft portion 18a, for example, a screw is formed. There is a method in which a washer 19 having a hole slightly larger than the diameter of the bolt shaft is inserted into the front shaft portion 18 and then a screw is formed so that the washer 19 cannot be removed. This is the same as the built-in method.
The washer 19 can freely rotate around the non-screw shaft portion 18b.

<Description of cover member>
A cover member 24 is secured to the flat portion 11b of the upper metal plate 11 so as to form a space 23 capable of accommodating the head 17 of the bolt 16 with the flat portion 11b. The cover member 24 is formed in a cup shape by drawing a thin plate material.
The cover member 24 includes a ceiling plate portion 24a that is parallel to the flat portion 11b at a predetermined height and faces the washer 19, and a peripheral wall plate portion 24b that is provided at right angles to the ceiling plate portion 24a. have.
An opening 25 similar to the outer shape of the washer 19 and slightly larger than the outer shape of the washer 19 is formed in the ceiling plate portion 24 a of the cover member 24.

<Assembly procedure of bolt assembly and cover member>
The procedure for assembling the bolt assembly 22 and the cover member 24 to the rotating object guard 7 is as follows. First, the bolt assembly 22 is assembled into the rotating object guard 7 through the shaft 18 in the bolt insertion hole 14. Next, the cover member 24 is positioned at a predetermined position where the head portion 17 of the bolt 16 is included inside the opening 25 in plan view, and the cover member 24 and the rotating object guard 7 are joined by welding.

<Description of bolt detachable position and bolt non-detachable position>
As shown in FIG. 4A, when the opening 25 of the cover member 24 and the washer 19 are viewed so as to overlap each other, that is, in plan view, the washer 19 is non-screw shaft with respect to the opening 25 of the cover member 24. When the positional relationship is shifted around the portion 18b, this is referred to as a bolt non-detachable position.
As shown in FIG. 5A, when the opening 25 of the cover member 24 and the washer 19 are in a positional relationship in plan view, this is referred to as a bolt detachable position.
In the state of the bolt attachable / detachable position shown in FIG. 5A, when the washer 19 is rotated around the non-screw shaft portion 18b, the bolt attachable / detachable position shown in FIG. .
4A, the washer 19 is rotated around the non-screw shaft portion 18b, and only one place in one rotation is opened to the opening 25 of the cover member 24 in plan view. This is a fitting position, that is, a bolt attachable / detachable position shown in FIG.
In this way, a bolt attachable / detachable position where the washer 19 can pass through the opening 25 and a bolt attaching / detaching where the washer 19 cannot pass through the opening 25 by rotating the washer 19 around the non-screw shaft portion 18 b of the bolt 16. It is possible to switch between impossible positions.

<Description of Effects of Bolt Drop-off Prevention Structure of Embodiment (1)>
As shown in FIGS. 3 (a) and 3 (b), in a bolt non-detachable position and in a bolt fastening state, when a hexagon wrench (not shown) is fitted into the head 17 of the bolt 16 and the bolt 16 is turned in a loosening direction, The bolt 16 moves in the bolt pulling direction D according to the loosening operation of the bolt 16 until the screw 16 is released from the screw hole 15. As shown in FIG. 4B, when the bolt 16 is removed from the screw hole 15, the fastening of the rotating object guard 7 and the stay 13 is released.
As shown in FIG. 4A, the washer 19 cannot pass through the opening 25 of the cover member 24 when it is in the bolt non-detachable position. Even if the bolt 16 tries to come out of the rotating object guard 7 by moving in the direction D, the outer periphery of the washer 19 is caught on the edge of the opening 25 and the movement of the bolt 16 in the pulling direction D is stopped. Thereby, it is possible to prevent the bolt 16 from falling off the rotating object guard 7.

<Description of Effects of Bolt Drop-off Prevention Structure of Embodiment (2)>
As shown in FIG. 5A, when the bolt is in the detachable position, the washer 19 can pass through the opening 25 of the cover member 24, so that the bolt 16 can be inserted into and removed from the rotating object guard 7 through the opening 25. It becomes. As a result, the bolt 16 can be easily attached and detached.
When the screw thread of the bolt 16 is crushed, the bolt 16 needs to be replaced. When the bolt 16 is replaced, the bolt 16 can be easily replaced by setting the bolt 16 in a detachable position.
For convenience of manufacture, there is a case where it is desired to incorporate the bolt 16 into the rotating object guard 7 after the cover member 24 is welded to the rotating object guard 7. In such a case, the bolt 16 can be rotated through the opening 25 by fitting the washer 19 to the opening 25 of the cover member 24 which has already been welded to the rotating object guard 7 so that the bolt is detachable. It can be easily incorporated into the guard 7.

<Description of Effects of Bolt Drop-off Prevention Structure of Embodiment (3)>
As shown in FIG. 3B, the bolt head 17 is accommodated in the space 23 between the cover member 24 and the rotating object guard 7 in the bolt fastening state. Thereby, the head 17 of the bolt 16 can be protected by the cover member 24. Accordingly, when a falling object collides with the rotating object guard 7 or when the rotating object guard 7 is dropped, an impact force acts on the head 17 of the bolt 16 and the head 17 of the bolt 16 is deformed. It is possible to prevent the neck of the bolt 16 from being bent.

<Explanation of terms>
The rotating object guard 7 corresponds to the “attached member” of the present invention.
The stay 13 corresponds to the “attachment member” of the present invention.

  The bolt drop-off prevention structure according to the present invention has been described based on one embodiment. However, the present invention is not limited to the structure described in the above-described embodiment, and the structure is appropriately set within the scope of the invention. Can be changed.

<Description of Modification (1)>
Instead of the washer 19, for example, washers 19A to 19F shown in FIGS. 7A to 7F may be employed.
In the washer 19 </ b> A shown in FIG. 7A, a semicircular cutout 31 is formed on the outer peripheral portion at a single position on the positive y-axis. The washer 19A has a shape that is line symmetric with respect to the y axis as the axis of symmetry. An opening 25A having a shape similar to the outer shape of the washer 19A and slightly larger than the outer shape of the washer 19A is formed in the ceiling plate portion 24a of the cover member 24.

  In the washer 19B shown in FIG. 7B, a linear notch 32 that is parallel to the x-axis is formed at the outer peripheral portion at a position on the positive y-axis, and the negative y-axis is formed. An arc-shaped notch 33 is formed at the upper position. The washer 19B has a shape that is line-symmetric with respect to the y-axis as a symmetry axis. An opening 25B having a shape similar to the outer shape of the washer 19B and slightly larger than the outer shape of the washer 19B is formed in the ceiling plate portion 24a of the cover member 24.

  In the washer 19C shown in FIG. 7C, a linear notch 34 that is parallel to the x axis is formed on the outer periphery of the washer 19C, and a negative y axis is formed. A sloped linear notch 35 is formed at an upper position and inclined with respect to the x-axis. The washer 19C has a non-axisymmetric shape with respect to the y-axis. An opening 25C having a shape similar to the outer shape of the washer 19C and slightly larger than the outer shape of the washer 19C is formed in the ceiling plate portion 24a of the cover member 24.

  In the washer 19D shown in FIG. 7D, a semicircular projection 36 is formed on the outer peripheral surface at a single position on the positive y-axis. The washer 19D has a shape that is line symmetric with respect to the y axis as the axis of symmetry. An opening 25D having a shape similar to the outer shape of the washer 19D and slightly larger than the outer shape of the washer 19D is formed in the ceiling plate portion 24a of the cover member 24.

  The washer 19E shown in FIG. 7 (e) is mounted in an eccentric state with respect to the non-screw shaft portion 18b of the bolt 16. An opening 25E that is similar in shape to the outer shape of the washer 19E and slightly larger than the outer shape of the washer 19E is formed in the ceiling plate portion 24a of the cover member 24.

  A washer 19F shown in FIG. 7 (f) is an elliptical washer having a major axis on the y-axis and a minor axis on the x-axis. A rhomboid opening 25F that encloses the outer shape of the washer 19F is formed in the ceiling plate portion 24a of the cover member 24. The washer 19F and the opening 25F are not similar to each other. However, if the washer 19F is rotated around the non-screw shaft portion 18b even in the state where the bolt is attachable / detachable as shown in FIG. A possible position is reached.

<Description of Modification (2)>
Also, a structure for preventing the bolt 16A from falling off as shown in FIGS. 8 (a) and 8 (b) may be employed.
As shown in FIG. 8B, the washer 19 is movable on the non-screw shaft portion 18b of the bolt 16A between a position where it hits the head 17 of the bolt 16A and a position where it hits the screw shaft portion 18a. It is said that. The stroke length S of the washer 19 on the non-screw shaft portion 18b is equal to or longer than the screwing length L of the screw shaft portion 18a into the screw hole 15.
The ceiling plate portion 24a of the cover member 24A is disposed at a predetermined height position with a slight gap t between the cover member 24A and the upper portion of the head portion 17 projects from the opening 25 when the bolt 16A is in a fastening state. It will be in a state to be.

  For example, when the rotating object guard 7 is fastened and fixed by a plurality of bolts 16A and the stroke length S on the non-screw shaft portion 18b of the washer 19 is not sufficient, all the bolts 16A are not loosened on average. Then, there is a risk that the rotating object guard 7 is deformed. That is, if the stroke length S on the non-screw shaft portion 18b of the washer 19 is insufficient, the washer 19 pushed up by the screw shaft portion 18a before the screw 16A is released from the screw hole 15 is released. If the bolt collides with the cover member 24A and the bolt loosening operation is continued thereafter, the rotating part guard 7 may eventually be lifted locally by the washer 19 and bent.

Therefore, in the structure for preventing the bolt 16A from falling off according to this modification, the stroke length S of the washer 19 on the non-screw shaft portion 18b is slightly longer than the screwing length L into the screw hole 15 of the screw shaft portion 18a. The stroke length is set with a margin of margin. Thereby, during the loosening operation of the bolt 16A, only the bolt 16A moves in the bolt pulling direction D, and it is possible to prevent the trouble that the rotating portion guard 7 is locally lifted and bent by the washer 19 in advance. it can.
Accordingly, the rotating object guard 7 can be removed by the same operation as the normal bolt loosening operation without the need for an inefficient operation in which all the bolts 16A have to be loosened on average.

  Further, in the dropout prevention structure shown in FIGS. 8A and 8B, the cover member 24A having a lower volume than the cover member 24 in the above embodiment is used, so that the space above the bolts is effectively used. Of course, it can be suitably applied to the fastening portion when there is no room in the space above the bolt.

  The bolt fall-off prevention structure of the present invention has the characteristic that the bolt can be prevented from dropping off, and the bolt can be easily attached / detached. It can be suitably used for bolt fastening applications of construction machines such as necessary excavators, bulldozers, wheel loaders and the like.

7 Rotating object guard (attached member)
13 Stay (Mounting member)
16, 16A Bolt 17 Head 18 Shaft 19, 19A-19F Washer 20, 31-35 Notch 24, 24A Cover member 25, 25A-25F Open 36 Protrusion

Claims (4)

A bolt fall-off prevention structure for fastening a member to be attached to a member to be attached,
A washer that is attached to the shaft portion of the bolt inseparably and is configured to be rotatable around the shaft portion;
A cover member having a plate portion facing the washer;
An opening formed in the plate portion of the cover member,
A bolt detachable position where the washer can pass with respect to the opening and a bolt detachable position where the washer cannot pass with respect to the opening according to the rotation angle of the washer about the shaft portion of the bolt. A structure for preventing the bolt from falling off.   The bolt washer-off prevention structure according to claim 1, wherein the washer has a shape having a notch in at least one of its outer peripheral portions.   The bolt washer-off prevention structure according to claim 1, wherein the washer has a shape having a protrusion at least at one location on an outer peripheral surface thereof.   The bolt washer-off prevention structure according to claim 1, wherein the washer is mounted in an eccentric state with respect to the shaft portion of the bolt.

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