Fastening structure of components

Abstract

To provide a fastening structure capable of screwing and fastening a first part and a second part which are properly positioned.SOLUTION: A fastening structure of parts comprises a first part 10 having a base portion 12 and one or more standing walls 16 erected from the base portion 12 and defining a receiving passage 18, and a second part 40 having an insertion portion 42 that is inserted into the receiving passage 18 until a position coming into contact with the base portion 12, and which is screwed and fastened to the base portion 12 by a fastening bolt 50 in such a state. The one or more standing walls 16 include an abutting surface 22 against which a portion of a peripheral surface of the insertion portion 42 is pressed when inserting the insertion portion 42 into the receiving passage 18, and positioning ribs 30 which are engaged with the other portion of the peripheral surface of the insertion portion 42 when inserting the insertion portion 42 into the receiving passage 18. Out of the positioning ribs 30, an end surface on an upstream side in a fastening rotational direction Ra of the fastening bolt 50 is substantially orthogonal to the fastening rotational direction Ra.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] This specification discloses a fastening structure between a first component and a second component.

Background Art

[0002] Conventionally, in order to position a first component and a second component without play, it has been proposed to provide a rib on one of the first component and the second component that interferes with the other. For example, Patent Document 1 discloses a technique for positioning a mounting plate on which a switch or the like is fixedly arranged on a design panel without play. In Patent Document 1, two walls are erected from the design panel, and the front end of the mounting plate is inserted between these two walls. Here, the interval between the two walls is substantially the same as the thickness of the mounting plate, and a wedge-shaped rib protruding toward the other is formed on one of the two walls. In this case, when the mounting plate is inserted between the two walls, one of the rib and the mounting plate is deformed so as to follow the shape of the other, and the two are in close contact without a gap. Thereby, the design panel and the mounting plate are positioned without play.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the mounting plate and the design panel are assembled by inserting the mounting plate between the two walls, and the mounting plate and the design panel are not screwed together. However, depending on the type of part, the first and second parts may be positioned using ribs and then screwed together with a fastening member. In this case, the force of tightening the fastening member may cause one of the first or second parts to rotate relative to the other, resulting in a misalignment of their positions. As a result, it was difficult to screw together the first and second parts while they were properly positioned using conventional technology.

[0005] Therefore, this specification discloses a fastening structure that allows the first and second parts to be screwed together while being properly positioned. [Means for solving the problem]

[0006] The fastening structure for a component disclosed herein comprises a first component having a base and one or more vertical walls extending from the base and defining a receiving passage, and a second component having an insertion portion that is inserted into the receiving passage to a position in contact with the base and is screw-fastened to the base by a fastening member, wherein the one or more vertical walls include a contact surface against which a part of the circumferential surface of the insertion portion is pressed when the insertion portion is inserted into the receiving passage, and a positioning rib that bites into another part of the circumferential surface of the insertion portion when the insertion portion is inserted into the receiving passage, and the end face of the positioning rib on the upstream side in the tightening rotation direction of the fastening member is substantially perpendicular to the tightening rotation direction.

[0007] In this case, one or more engagement grooves are formed on the top portion of the positioning rib that protrudes toward the center of the receiving passage, and the end face of the engagement groove on the upstream side in the insertion direction of the insertion portion may be substantially perpendicular to the insertion direction.

[0008] Furthermore, of the positioning ribs, at least a certain range from the upstream end in the insertion direction of the insertion portion may be narrower in width as it moves upstream in the insertion direction.

[0009] Furthermore, of the positioning ribs, at least a certain range from the upstream end in the insertion direction of the insertion portion may have a smaller protrusion amount as it approaches the upstream side in the insertion direction. [Effects of the Invention]

[0010] According to the fastening structure of the component disclosed herein, the upstream end face of the positioning rib in the tightening rotation direction is substantially perpendicular to the tightening rotation direction. Therefore, when tightening the fastening member, the rotation of the second component relative to the first component is effectively suppressed. As a result, the first and second components can be screwed together while in proper position. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic perspective view of the first and second parts. [Figure 2] This is a cross-sectional view of the first component. [Figure 3] This is a cross-sectional view of the first and second parts, taken along line AA in Figure 2. [Figure 4] This is a perspective view of the area around the positioning rib. [Figure 5] This is a front view of the positioning rib. [Figure 6] Figure 5 is a cross-sectional view of BB. [Figure 7] This is a schematic cross-sectional view when the device is inserted into the insertion section of the receiving passage. [Figure 8] This is a schematic cross-sectional view of the first component of the comparative example when it is inserted into the insertion section of the receiving passage. [Figure 9] This is a longitudinal cross-sectional view of the area around the engagement groove when the insertion part is inserted into the receiving passage. [Modes for carrying out the invention]

[0012] The fastening structure of the components will be described below with reference to the drawings. Figure 1 is a schematic perspective view of the first component 10 and the second component 40. Figure 2 is a cross-sectional view of the first component 10, and Figure 3 is a cross-sectional view along line AA in Figure 2. In each drawing, only the main parts of the first component 10 and the second component 40 are shown, and other parts are omitted. In the following description, the upstream side in the insertion direction when inserting the insertion portion 42 of the second component 40 (described later) into the receiving passage 18 of the first component 10 will be referred to as "up". The two directions perpendicular to the vertical direction will be referred to as the front-back direction and the left-right direction. Therefore, "up" in the following description may be a direction different from the upward direction in the direction of gravity.

[0013] The first component 10 has a base portion 12 and a receiving cylinder 15 that extends from the base portion 12. As shown in Figure 3, the base portion 12 is a flat plate-shaped portion. A fastening hole 14 is formed in this base portion 12, penetrating in the thickness direction. This fastening hole 14 is sufficiently larger than the screw diameter of the fastening bolt 50 (see Figure 3). In addition, although not shown in Figure 1, other parts may be connected to the base portion 12.

[0014] The receiving cylinder 15 is supported by the upper surface of the base 12. This receiving cylinder 15 is composed of four vertical walls 16 connected to each other at a 90-degree angle. Therefore, the receiving cylinder 15 as a whole is a rectangular tube surrounding the fastening hole 14. Hereafter, the internal space of the receiving cylinder 15, that is, the space surrounded by the four vertical walls 16, will be referred to as the "receiving passage 18". As shown in Figures 2 and 3, a band portion 20 is formed on the inner surface of each vertical wall 16 (i.e., the surface facing the receiving passage 18), extending from the upper end to the lower end of the vertical wall 16. The band portion 20 is a band-shaped projection that protrudes slightly from its surroundings and is elongated in the vertical direction. As is clear from Figure 3, a certain range of this band portion 20 from the upper end is an inclined portion 20a that slopes so that the amount of protrusion increases sharply as it goes downward from the upper end (i.e., from the upstream end in the insertion direction to the downstream end). By providing the inclined portion 20a, it becomes easier to insert the insertion portion 42 of the second component 40, which will be described later, into the receiving passage 18. The portion of the band 20 below the inclined portion 20a is also inclined such that the amount of protrusion gradually increases as it goes downwards, but its inclination angle is smaller than that of the inclined portion 20a.

[0015] Furthermore, as is clear from Figure 2, positioning ribs 30 are formed on two of the four band portions 20, while positioning ribs 30 are not formed on the remaining two band portions 20. The surfaces of the band portions 20 that do not have positioning ribs 30 function as contact surfaces 22 against which the circumferential surface of the insertion portion 42 is pressed. In this example, the positioning ribs 30 and the contact surfaces 22 are arranged to face each other across the fastening hole 14. Specifically, positioning ribs 30 are provided on the left and rear vertical walls 16, and contact surfaces 22 are provided on the right and front vertical walls 16.

[0016] The positioning rib 30 protrudes from the surface of the band portion 20 and is a long rib in the vertical direction. As shown in Figure 2, the cross-sectional shape of this positioning rib 30 is approximately triangular. When the insertion portion 42 is inserted into the receiving passage 18, the positioning rib 30 bites into the circumferential surface of the insertion portion 42 and presses the insertion portion 42 against the contact surface 22, which will be described later.

[0017] Regarding the detailed configuration of this positioning rib 30, it will be described with reference to FIGS. 4 to 6. FIG. 4 is a perspective view of the periphery of the positioning rib 30. Further, FIG. 5 is a view of the positioning rib 30 seen from the front, and FIG. 6 is a sectional view taken along the line B-B of FIG. 5.

[0018] As shown in FIG. 4, the positioning rib 30 is a rib that extends vertically from a position below the inclined portion 20a of the belt portion 20 to the lower end of the vertical wall 16. The cross-sectional shape of the positioning rib 30 (that is, the cross-sectional shape in a plane orthogonal to the insertion direction) is, as shown in FIG. 2, a substantially right-angled triangular shape having a plane substantially orthogonal to the surface of the belt portion 20 and a plane inclined at a non-right angle to the surface of the belt portion 20. The reason for making the cross-sectional shape of the positioning rib 30 a substantially right-angled triangular shape will be described later.

[0019] A certain range from the upper end of the positioning rib 30 becomes an approach region 31 that first contacts the inserted insertion portion 42. As shown in FIG. 5, in this approach region 31, the positioning rib 30 gradually narrows in width as it approaches the upper end. In other words, the upper end of the positioning rib 30 has a sharp tip shape. Also, as shown in FIG. 6, in the approach region 31, the protruding amount of the positioning rib 30 from the belt portion 20 gradually decreases as it approaches the upper end. By adopting such a configuration, in the initial stage of inserting the insertion portion 42 into the receiving passage 18, the contact area between the positioning rib 30 and the positioning projection 44 can be reduced, and thereby, the positioning rib 30 can easily bite into the positioning projection 44.

[0020] Also, as shown in FIGS. 4 and 6, near the lower end of the positioning rib 30, two engaging grooves 36 are formed at intervals in the vertical direction. Each engaging groove 36 is a groove formed at the top of the positioning rib 30 (that is, the portion that protrudes most into the receiving passage 18). As shown in FIG. 6, the upper end surface of this engaging groove 36 (that is, the end surface on the upstream side in the insertion direction) is substantially orthogonal to the vertical direction. And the longitudinal cross-sectional shape of the engaging groove 36 is a substantially right-angled triangle. The reason for providing such an engaging groove 36 will also be described later.

[0021] The second part 40 has an insertion portion 42 that is inserted into the receiving passage 18. Naturally, the second part 40 may have other parts in addition to the insertion portion 42, but these other parts are omitted from the drawings. The insertion portion 42 is the part that is inserted into the receiving passage 18. As shown in Figures 1 and 3, in this example, the insertion portion 42 is substantially cylindrical. Four positioning protrusions 44 are formed on the circumferential surface of the insertion portion 42. These positioning protrusions 44 are band-shaped protrusions that extend from the lower end to the upper end of the insertion portion 42. The four positioning protrusions 44 are provided at equal intervals in the circumferential direction so that they face and contact the contact surface 22 and the positioning rib 30 when the insertion portion 42 is inserted into the receiving passage 18.

[0022] In Figure 3, a screw hole 46 is formed on the bottom surface of the insertion part 42, as shown by the dashed line. When the insertion part 42 is fully inserted into the receiving passage 18, this screw hole 46 aligns vertically with the fastening hole 14 of the first part 10. With the fastening hole 14 and the screw hole 46 aligned, the fastening bolt 50 is screwed into the screw hole 46 from below, thereby fastening the first part 10 and the second part 40 together.

[0023] Here, both the first part 10 and the second part 40 are made of resin. However, as will be explained in detail later, in this example, it is necessary to ensure that the positioning rib 30 is securely engaged with the positioning projection 44 of the second part 40. Therefore, the positioning rib 30 needs to be harder than the positioning projection 44. Accordingly, in this example, the first part 10 is made of a resin that is harder than the second part 40. Alternatively, the first part 10 and the second part 40 may be made of the same material, while the surface of the positioning rib 30 may be coated to increase its hardness.

[0024] Next, the procedure for fastening the second part 40 to the first part 10 will be described. When fastening the second part 40 to the first part 10, the insertion portion 42 of the second part 40 is inserted into the receiving passage 18 of the first part 10. Here, the receiving passage 18 has a positioning rib 30 and a contact surface 22 facing each other. The minimum distance D1 (see Figure 3) between the positioning rib 30 and the contact surface 22 is smaller than the maximum outer diameter D2 of the insertion portion 42. Therefore, when the insertion portion 42 is inserted into the receiving passage 18, the positioning rib 30 bites into the positioning projection 44 of the insertion portion 42 and presses the insertion portion 42 against the contact surface 22. Figure 7 is a schematic cross-sectional view when the insertion portion 42 is inserted into the receiving passage 18. As shown in Figure 7, the insertion portion 42, and thus the second part 40, is positioned relative to the first part 10 by being pressed against the two contact surfaces 22.

[0025] Once the end of the insertion portion 42 contacts the base portion 12 and the insertion of the insertion portion 42 into the receiving passage 18 is complete, in other words, once the positioning of the second part 40 relative to the first part 10 is complete, the fastening bolt 50 is inserted from below into the fastening hole 14 and screwed into the screw hole 46. Then, by tightening this fastening bolt 50 sufficiently, the second part 40 is screwed and fastened to the first part 10.

[0026] When the fastening bolt 50 is tightened, a force in the tightening rotation direction Ra acts on the second part 40, causing the second part 40 to rotate relative to the first part 10. If the second part 40 rotates relative to the first part 10, the relative positional relationship between the two will naturally change, resulting in poor positioning. In this example, in order to prevent such rotation of the second part 40 relative to the first part 10, the cross-sectional shape of the positioning rib 30 is made into a roughly right-angled triangle. This will be explained in comparison with the comparative example.

[0027] Figure 8 is a schematic cross-sectional view of the second part 40 inserted into the receiving passage 18 of the first part 10* of the comparative example. As shown in Figure 8, the first part 10* of the comparative example is also provided with a contact surface 22 and a positioning rib 30*. However, the positioning rib 30* of the comparative example does not have a surface that rises perpendicularly from the surface of the band portion 20, and the cross-sectional shape of the positioning rib 30* is approximately an isosceles triangle.

[0028] In this case, when the fastening bolt 50 is rotated in the tightening rotation direction Ra, the insertion portion 42 also attempts to move in the tightening rotation direction Ra. As a result, the upstream end face 30a* of the positioning rib 30 in the tightening rotation direction Ra comes into strong contact with the biting surface of the insertion portion 42. In the comparative example, the inclination angle of the upstream end face 30a* with respect to the tightening rotation direction Ra is small. Therefore, when the biting surface of the insertion portion 42 comes into strong contact with the upstream end face 30a*, some of that force is converted into a radial force. As a result, there was a risk that the insertion portion 42 would move over the positioning rib 30* and rotate within the receiving passage 18. When the insertion portion 42 rotates, naturally, the positioning of the second part 40 relative to the first part 10* becomes misaligned.

[0029] Therefore, as repeatedly stated in this example, the cross-sectional shape of the positioning rib 30 is made to be approximately a right triangle. More precisely, as shown in Figure 7, the upstream end face 30a of the positioning rib 30 in the tightening rotation direction Ra is made approximately perpendicular to the tightening rotation direction Ra. With this configuration, even if a force in the tightening rotation direction Ra acts on the second part 40 and the biting surface of the insertion part 42 strongly contacts the upstream end face 30a, this contact force (i.e., circumferential force) is not converted into a radial force. As a result, the insertion part 42 is effectively prevented from going over the positioning rib 30, and the positioning of the second part 40 relative to the first part 10 is maintained in an appropriate state. Consequently, according to this example, the first part 10 and the second part 40 can be screwed together in an appropriately positioned state.

[0030] As mentioned above, and as shown in Figures 4 to 6, in this example, the width and protrusion of the upper end of the positioning rib 30 gradually decrease as it approaches the upper end. Therefore, when the end of the insertion portion 42 is inserted into the receiving passage 18, the contact area between the positioning rib 30 and the positioning projection 44 can be reduced. This reduces the resistance when the positioning rib 30 begins to bite into the positioning projection 44, and the positioning rib 30 can be bitten into the positioning projection 44 with a relatively small force.

[0031] Furthermore, as shown in Figures 4 and 6, in this example, two engagement grooves 36 are provided near the lower end of the positioning rib 30. The reason for providing these engagement grooves 36 will be explained with reference to Figure 9. Figure 9 is a longitudinal cross-sectional view of the area around the engagement grooves 36 when the insertion part 42 is inserted into the receiving passage 18. When the insertion part 42 is pushed towards the base part 12, that is, downwards, the positioning rib 30 presses against the positioning projection 44 and bites into the positioning projection 44. As shown in Figure 9, when engagement grooves 36 are provided, a portion of the material of the positioning projection 44, which is pressed by the positioning rib 30, escapes towards the engagement grooves 36. Hereinafter, the portion of the positioning projection 44 that escapes towards the engagement grooves 36 and bulges out will be called the "bulging portion 45". Also, the dashed line in Figure 9 shows the shape of the insertion part 42 before deformation.

[0032] Here, the upper end surface of the engagement groove 36 is approximately perpendicular to the insertion direction of the insertion portion 42. Therefore, if the bulge 45, which is part of the positioning projection 44, enters the engagement groove 36, the bulge 45 will catch on the upper end surface of the engagement groove 36 even if the insertion portion 42 is pulled out of the receiving passage 18. In other words, the insertion portion 42 will not easily detach from the receiving passage 18. Therefore, even if the worker releases their hand from the second part 40 during the insertion of the insertion portion 42 or during the tightening of the fastening bolt 50, the insertion portion 42 can easily maintain its inserted state in the receiving passage 18. In other words, by providing the engagement groove 36, the worker can release one hand from the second part 40 during the work, improving the worker's work efficiency.

[0033] The configuration described above is merely an example, and other configurations can be changed as long as the first component 10 is provided with a positioning rib 30 that bites into the circumferential surface of the insertion portion 42, and the upstream end face 30a of the positioning rib 30 in the tightening rotation direction Ra is substantially perpendicular to the tightening rotation direction Ra. For example, in this example, an engagement groove 36 is provided in the middle of the positioning rib 30, but such an engagement groove 36 is not required. Also, the width and protrusion amount of the positioning rib 30 are continuously changed around the upper end of the positioning rib 30, but these may remain constant. Furthermore, in this example, the first component 10 is provided with two contact surfaces 22 and two positioning ribs 30, but the number of these may be changed. For example, consider the case where the second component 40 is positioned only in the front-rear direction relative to the first component 10, and there is no need to position it in the left-right direction. In this case, contact surfaces 22 and positioning ribs 30 only need to be provided on the front and rear vertical walls 16, and contact surfaces 22 and positioning ribs 30 do not need to be provided on the right and left vertical walls 16. In this case, the right and left vertical walls 16 themselves may be omitted. Therefore, the number of vertical walls 16 may also be changed as appropriate. Furthermore, the shape of the insertion portion 42 may also be changed as appropriate; for example, the positioning projection 44 may be omitted. [Explanation of symbols]

[0034] 10,10* First part, 12 Base, 14 Fastening hole, 15 Receiving cylinder, 16 Vertical wall, 18 Receiving passage, 20 Band, 22 Contact surface, 30,30* Positioning rib, 30a,30a* Upstream end face, 31 Approach area, 36 Engagement groove, 40 Second part, 42 Insertion part, 44 Positioning projection, 45 Bulging part, 46 Screw hole, 50 Fastening bolt, Ra Tightening rotation direction.

Claims

1. A first component having a base and a plurality of vertical walls that stand up from the base and define a receiving passage, A second component having an insertion portion which is inserted into the receiving passage to a position where it contacts the base and is screwed into the base by a fastening member in that state, The plurality of vertical walls are provided, When the insertion portion is inserted into the receiving passage, a contact surface against which a part of the circumferential surface of the insertion portion is pressed, When the insertion portion is inserted into the receiving passage, a positioning rib bites into another part of the circumferential surface of the insertion portion, The positioning rib includes such that the end face of the positioning rib on the upstream side in the tightening rotation direction of the fastening member is substantially perpendicular to the tightening rotation direction. A fastening structure for components characterized by the following features.

2. A fastening structure for a component according to claim 1, One or more engagement grooves are formed on the top portion of the positioning rib that protrudes toward the center of the receiving passage. Of the engagement grooves, the end face on the upstream side in the insertion direction of the insertion portion is substantially perpendicular to the insertion direction. A fastening structure for components characterized by the following features.

3. A fastening structure for a component according to claim 1, A fastening structure for a component, characterized in that, of the positioning ribs, at least a certain range from the upstream end in the insertion direction of the insertion portion becomes narrower in width as it proceeds upstream in the insertion direction.

4. A fastening structure for a component according to claim 1 or 3, A fastening structure for a component, characterized in that, of the positioning ribs, at least a certain range from the upstream end in the insertion direction of the insertion portion, the amount of protrusion decreases as it approaches the upstream side in the insertion direction.

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