Screw fastening structure and fastened member

Abstract

To provide a screw fastening structure capable of suppressing generation of shavings while using a toothed washer.SOLUTION: A screw fastening structure 1 for screw-fastening a member to be fastened 53 to a counterpart member 51 includes a screw 11 screwed into the counterpart member 51, a toothed washer 13 provided with a plurality of teeth 131 protruding toward an outer periphery in a circumferential direction, and a contact surface 15 provided on the member to be fastened 53 so that a bearing surface of the screw 11 is pressed against the contact surface 15 via the toothed washer 13, wherein the contact surface 15 is provided with a convex portion 150 that restricts rotation of the toothed washer 13. The protrusion 150 interferes with the teeth 131 of the toothed washer 13, thereby restricting the rotation of the toothed washer 13 caused by the screwing of the screw 11.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a screw fastening structure for fastening two members together using a screw. [Background technology]

[0002] Conventionally, when assembling industrial products, screw fastening structures are often used that fasten, for example, two components together using screws. When industrial products are used over a long period of time, there is a risk that the screws may loosen due to environmental changes such as temperature changes, vibrations, etc. To prevent screws from loosening, for example, a washer interposed between the seat surface and the contact surface of the screw is effective. A toothed washer with multiple teeth protruding toward the outer or inner circumference is known as a washer that is highly effective in preventing screws from loosening (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-089875 Summary of the Invention [Problem to be solved by the invention]

[0004] While toothed washers can reliably prevent screws from loosening by having the teeth bite into the parts, there is a problem in that the teeth can scrape the surface of the parts, creating shavings.

[0005] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide a screw fastening structure and fastened members that can suppress the generation of shavings while using toothed washers. [Means for solving the problem]

[0006] One aspect of the present invention is a fastened member that is fastened to a mating member with a screw using a washer, The screw comprises a head and a neck, and has a bearing surface at the base of the neck relative to the head, The washer is a toothed washer having one end supported by an annular portion that passes through the neck of the screw and a plurality of teeth protruding toward the outer or inner circumference, A restricting portion is provided on the contact surface against which the seating surface of the screw presses via the washer, for restricting rotation of the washer as the screw is screwed in, The restricting portion is located on the fastened member and is configured to interfere with at least one of the teeth of the washer, thereby restricting the rotation of the washer that accompanies the screw being threaded.

[0007] One aspect of the present invention is a screw fastening structure for screw-fastening a fastened member to a mating member, a screw consisting of a head and a neck, with a seat provided at the base of the neck relative to the head; a washer having a plurality of teeth projecting toward the outer or inner circumference, one end of which is supported by an annular portion that passes through the underside of the screw head; a through hole drilled in the fastened member for allowing a head of the screw to pass through; a contact surface provided on the fastened member so that the seat surface of the screw presses against the contact surface via the washer, The contact surface is provided with a restricting portion that restricts rotation of the washer as the screw is screwed in, The screw is threaded into the mating member with its head passing through a through hole drilled in the fastened member, The restricting portion interferes with at least one of the teeth of the washer, and rotation of the washer accompanying screw threading is restricted. [Effects of the Invention]

[0008] In the fastened components according to the present invention, a restricting portion is provided on the contact surface against which the seating surface of the screw presses via the washer, restricting rotation of the washer as the screw is screwed in. This restricting portion restricts rotation of the washer as the screw is screwed in, reducing shavings that may be generated when the teeth of the washer scrape the contact surface. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a shift lever device including a screw fastening structure. [Figure 2] Rear view of the shift lever. [Figure 3] FIG. 2 is an explanatory diagram of a combination of a shift knob and a shaft. [Figure 4] Perspective view of a screw. [Figure 5] FIG. [Figure 6] An enlarged view of the screw contact surface (shift knob). [Figure 7] FIG. [Figure 8] FIG. 10 is an explanatory diagram showing a state in which a toothed washer is combined with the contact surface. [Figure 9] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The embodiments of the present invention will be specifically described using the following examples. Example 1 This example is an example of a screw fastening structure 1 in which a fastened member is screwed to a mating member by utilizing a toothed washer 13. The details of this structure will be described with reference to Figs.

[0011] This example illustrates a screw fastening structure 1 applied to a shift lever device 5 for a vehicle. The shift lever device 5 in Fig. 1 is a device for selecting a shift range set in an automatic transmission (not shown) mounted on a vehicle. The shift lever device 5 is disposed, for example, in a center console provided in front of the dashboard of the vehicle.

[0012] The shift lever device 5 includes a shift lever 50 that is operated by the driver. The shift lever device 5 is connected via a signal line to an ECU (an in-vehicle computer unit, not shown) that controls the automatic transmission, and converts the operation information of the shift lever 50 by the driver into an electrical signal and inputs it to the ECU.

[0013] As shown in FIG. 1, in the shift lever device 5, a shift lever 50 protrudes into the vehicle interior via a shift panel 55. The shift lever 50 is configured by attaching a shift knob 53, which serves as a handle for the driver, to the tip of a shaft 51, which is an example of a rod-shaped member. The shaft 51 is a hollow pipe made of metal such as aluminum. The shift knob 53 is a molded product made of, for example, a resin material.

[0014] Shaft 51 is journaled at a lower position inside shift panel 55 so as to be rotatable in one predetermined direction. The rotation direction of shaft 51 is the front-to-rear direction of a vehicle (not shown). A slit-shaped gate 550 is provided in shift panel 55 to allow shaft 51 to rotate and displace, and further, an indicator 552 that indicates shift ranges such as P range, R range, and D range is provided along gate 550.

[0015] The shift knob 53 (FIG. 1) is configured to include a grip portion 531 that the driver holds in the palm of his / her hand, and a tubular portion 533 into which the shaft 51 is inserted. The tubular portion 533 has a cylindrical internal space and is tubular in shape. The shaft 51, which has a circular cross section, can be inserted into the tubular portion 533 with little clearance.

[0016] As shown in FIG. 2 , which shows the shift lever 50 viewed from the back side (dashboard side), the shift knob 53 is fixed to the shaft 51 via a screw fastening structure 1 including a screw 11. The shift knob 53 is fastened to the shaft 51 with screws at two locations. The resin shift knob 53 is an example of a member to be fastened with screws to the shaft 51. The metal pipe shaft 51 is an example of a member to which the shift knob 53 is fastened with screws.

[0017] 3, through holes 100 for passing the screws 11 are provided at two locations along the longitudinal direction in the cylindrical portion 533 of the shift knob 53. A contact surface 15 for the screw 11 (seat surface 115) is formed on the outer periphery of the through hole 100. Note that since the screw fastening structure 1 of this example is a fastening structure that uses a toothed washer 13, the screw 11 (seat surface 115) presses against the contact surface 15 via the toothed washer 13.

[0018] A threaded hole 110 corresponding to the through hole 100 of the cylindrical portion 533 is drilled in the side wall of the shaft 51 (FIG. 3). With the shaft 51 inserted into the cylindrical portion 533 of the shift knob 53, by appropriately adjusting the position of the grip portion 531 in the rotational direction, it is possible to bring the through hole 100 and the threaded hole 110 into communication. When the through hole 100 of the cylindrical portion 533 and the threaded hole 110 of the shaft 51 are in communication, the screw 11 can be threaded in, and the shift knob 53 can be fastened to the shaft 51.

[0019] The screw fastening structure 1 of this example is configured to include a screw 11 (FIG. 4) that is threaded into a threaded hole 110 of a shaft 51, a toothed washer 13 (FIG. 5) that is an example of a washer, and a contact surface 15 (FIG. 6) for the screw 11 that is provided on a cylindrical portion 533. In the screw fastening structure 1, the shift knob 53 is fastened to the shaft 51 by the toothed washer 13, as described above, with the screw 11 prevented from loosening.

[0020] The screw 11 (Fig. 4) is a fastener consisting of a head 114 and a neck 117, with a bearing surface 115 at the base of the neck 117 relative to the head 114. The screw 11 in this example is a flat head screw with a flat head 114 and a tapered bearing surface 115. The screw 11 is a typical right-hand thread, and the direction of rotation when screwing in the screw 11 is clockwise.

[0021] The toothed washer 13 (Fig. 5) is a dish-shaped washer that is compatible with a flat head screw. The toothed washer 13 is an externally toothed washer with eight teeth 131 protruding toward the outer periphery. The toothed washer 13 has an annular portion 130 through which the neck 117 of the screw 11 passes. The eight teeth 131 are arranged at equal intervals around the circumference, with one end supported by the annular portion 130. In the dish-shaped toothed washer 13, the teeth 131 are formed along the inner peripheral surface of a roughly mortar-shaped mortar.

[0022] Each tooth 131 of the toothed washer 13 is slightly twisted around the radial axis. Therefore, both sides of each tooth 131 are slightly offset inward or outward (toward the back side) with respect to an ideal cone-shaped inner peripheral surface. Each tooth 131 of the toothed washer 13 of this example is twisted so that the side that corresponds to the forward rotation direction when the screw 11 is screwed in is located inside the cone shape, and the side that corresponds to the reverse rotation direction is located on the bottom side (back side) of the cone shape. After the screw is tightened, the side of each tooth 131 that corresponds to the reverse rotation direction bites into the contact surface 15, and the side of each tooth 131 that corresponds to the forward rotation direction bites into the bearing surface 115 (the screw 11). This biting of both sides of each tooth 131 highly reliably prevents the screw 11 from loosening.

[0023] As shown in Figure 6, the contact surface 15 (tubular portion 533) is a cone-shaped contact surface that corresponds to the tapered bearing surface 115 of the screw 11, which is a flat head screw. The contact surface 15 is formed as if it has been carved out from the outer periphery of the cylindrical portion 533. A rim 535 that is one step higher than the outer periphery of the cylindrical portion 533 is provided around the contact surface 15. The rim 535 forms an annular shape that surrounds the contact surface 15.

[0024] The contact surface 15 is provided with protrusions 150 for restricting the rotation of the toothed washer 13. The protrusions 150, which are an example of restricting portions, are provided at four locations in the circumferential direction. The protrusions 150 are protrusions erected on the outermost periphery of the cone-shaped contact surface 15. While the contact surface 15 is formed as if it had been carved into a cone shape, the protrusions 150 are flush with the edge 535 as if they had been left uncarved. The protrusions 150 are formed in a peninsula-like shape protruding from the edge 535 toward the inner periphery.

[0025] The convex portion 150 has wall surfaces 150a and 150b that face in the circumferential direction centered on the through-hole 100 at the center of the cone-shaped contact surface 15. The wall surface 150a forms a restricting surface and faces in the reverse rotation direction (counterclockwise, left rotation direction) when the screw 11 is screwed into the shaft 51. The wall surface 150b faces in the forward rotation direction when the screw 11 is similarly screwed into the shaft 51.

[0026] Next, a procedure for screwing the shift knob 53 to the shaft 51 using the screw fastening structure 1 of this example configured as described above will be described. When screwing the shift knob 53 to the shaft 51, first, as shown in Figure 7, the shaft 51 is inserted into the cylindrical portion 533, and the positions of the through-hole 100 and the threaded hole 110 are aligned to connect the through-hole 100 and the threaded hole 110.

[0027] The screw 11 with the toothed washer 13 disposed around the head 117 is prepared, and the screw 11 is screwed into the threaded hole 110 of the shaft 51. Note that FIG. 7 shows the state before the toothed washer 13 is disposed around the head 117. The direction of rotation (forward rotation direction) when screwing the screw 11 is clockwise. As the screw 11 is screwed in, the bearing surface 115 of the screw 11 presses against the contact surface 15 via the toothed washer 13. In this state where the bearing surface 115 presses against the contact surface 15, a clockwise rotation moment caused by the clockwise screwing of the screw 11 can act on the toothed washer 13.

[0028] In response to the clockwise rotation moment, the toothed washer 13 attempts to rotate clockwise (the forward rotation direction described above). There is a possibility that the toothed washer 13 will rotate as the screw 11 is threaded in. The toothed washer 13 can rotate up to a rotation position where one of the teeth 131 presses against the protrusion 150 (shift knob 53) (see FIG. 8). At this time, of the wall surfaces 150a and 150b of the protrusion 150, the wall surface 150a facing the opposite direction of rotation (counterclockwise) when the screw 11 is threaded in functions as a restricting surface that interferes with the tooth 131 of the toothed washer 13. The wall surface 150a of the protrusion 150 interferes with one of the teeth 131 of the toothed washer 13, thereby restricting the rotation of the toothed washer 13 beyond the above rotation position.

[0029] In this way, in the screw fastening structure 1 of this example, the rotation of the toothed washer 13 that accompanies the screw 11 being screwed in is restricted and kept to a minimum by the convex portion 150. By minimizing the rotation of the toothed washer 13 that accompanies the screw 11 being screwed in, it is possible to reduce to a nearly minimum the amount of shavings that can be generated when the contact surface 15 is scraped by the toothed washer 13.

[0030] The screw fastening structure 1 of this example can be applied to a variety of uses. For example, it can be applied to the assembly of in-vehicle parts that are attached to the vehicle interior, such as the shift lever device 5, as well as the installation of vehicle interior parts. The screw fastening structure 1 of this example is particularly effective in the vehicle interior, where the generation of shavings can be a problem. The screw fastening structure 1 of this example can also be applied to the installation of fixtures in a home, the assembly of building materials, etc. Furthermore, it is conceivable that the screw fastening structure 1 of this example can be applied to the assembly of parts in electrical appliances, etc.

[0031] This example is an example in which the proposed screw fastening structure 1 is applied to screw fastening a cylindrical member (tubular portion 533) to a rod-shaped member (shaft 51 in this example). The application of the screw fastening structure of this example is not limited to the combination of a rod-shaped member and a cylindrical member. The screw fastening structure of this example can be applied to various screw fastenings, such as screw fastening between plate-shaped members, screw fastening of plate-shaped members to structural members such as timber, and screw fastening between structural members such as timber.

[0032] In this example, a flat head screw is used as an example of a screw, but a pan head screw may also be used. Screws include not only small diameter screws but also large diameter bolts. As the toothed washer, an externally toothed washer 13 with teeth protruding toward the outer periphery is used as an example, but an internally toothed washer with teeth protruding toward the inner periphery may also be used. In the case of an internally toothed washer, it is preferable to provide a protrusion on the inner periphery side of the contact surface 15.

[0033] In this example, a protrusion 150 erected on the contact surface 15 is exemplified as a restricting portion that interferes with the teeth 131 of the toothed washer 13. The restricting portion is not limited to the protrusion 150. Any restricting portion may be used as long as it can restrict the rotation of the toothed washer 13 associated with the threading of the screw 11. For example, instead of the contact surface 15 on which the protrusion 150 is erected (see FIG. 7), a contact surface 15 having steps that form a sawtooth shape in the circumferential direction may be employed, as shown in FIG. 9. FIG. 9(a) shows a front view of the contact surface 15. The radial lines of the contact surface 15 indicate gap surfaces 158 that extend radially and have steps that form a sawtooth shape in the circumferential direction.

[0034] FIG. 9(b) shows sawtooth undulations along the circumference R of the contact surface 15 in FIG. 9(a). The horizontal axis in FIG. 9(b) represents clockwise angles when the vertical direction in FIG. 9(a) is set to 0°. The vertical axis in FIG. 9(b) represents the height of each point on the circumference R when a smooth contact surface (not shown) without any steps is set as the reference height. In FIG. 9(b), the height that protrudes inward from the cone shape is positive, and the height that recesses toward the back of the cone shape is negative. In the contact surface 15 in FIG. 9(a), the clockwise rotation of the toothed washer 13, which tends to rotate as the screw 11 is threaded in, can be reliably restricted by the step created by the gap surface 158. In other words, in the configurations of FIGS. 9(a) and 9(b), the gap surface 158 (step) functions as a restricting portion.

[0035] Although specific examples of the present invention have been described in detail as examples, these examples merely disclose examples of the technology encompassed by the claims. Needless to say, the scope of the claims should not be interpreted as being limited by the configurations, numerical values, etc. of the specific examples. The claims encompass technologies that are obtained by variously modifying, changing, or appropriately combining the specific examples using publicly known technology and the knowledge of those skilled in the art. [Explanation of symbols]

[0036] 1. Screw fastening structure 100 through holes 11 Screws 110 screw hole 114 Head 115 seat 117 Under the neck 13 Toothed washer (washer) 130 Circular section 131 teeth 15 Hitting Surface 150 Convex part (restriction part) 150a Wall (restricted surface) 150b wall 158 Gap surface (regulating surface, regulating part) 5 Shift lever device 50 Shift lever 51 Shaft (opposite part) 53 Shift knob (fastened part) 531 Grip 533 Cylinder part 535 En 55 Shift panel

Claims

1. A fastened member that is fastened to a mating member with a screw using a washer, The screw comprises a head and a neck, and has a bearing surface at the base of the neck relative to the head, The washer is a toothed washer having one end supported by an annular portion that passes through the neck of the screw and a plurality of teeth protruding toward the outer or inner circumference, A restricting portion is provided on the contact surface against which the seating surface of the screw presses via the washer, for restricting rotation of the washer as the screw is screwed in, The fastened member is configured so that the restricting portion interferes with at least one of the teeth of the washer and can restrict rotation of the washer that accompanies screwing in of the screw.

2. 2. The fastened member according to claim 1, wherein the screw is a countersunk head screw having a flat head and a tapered bearing surface, and the toothed washer is a dish-shaped toothed washer.

3. The fastened member according to claim 1 , wherein the restricting portion is provided in a plurality at intervals in the circumferential direction on the contact surface.

4. 4. The fastened member according to claim 3, wherein the restricting portion is a protrusion provided on the contact surface.

5. According to claim 1, the mating member is a rod-shaped member, and the fastened member is a member including at least a tubular portion that is fixed in a state where it is inserted onto the rod-shaped member, A through hole for passing a head of a screw through is drilled in the outer peripheral surface of the cylindrical portion, and the contact surface is formed on the outer periphery of the through hole.

6. 6. The fastened member according to claim 1, wherein the fastened member is a molded product made of a resin material.

7. A screw fastening structure for screw-fastening a fastened member to a mating member, a screw consisting of a head and a neck, with a seat provided at the base of the neck relative to the head; a washer having a plurality of teeth projecting toward the outer or inner circumference, one end of which is supported by an annular portion that passes through the underside of the screw head; a through hole drilled in the fastened member for allowing a head of the screw to pass through; a contact surface provided on the fastened member so that the seat surface of the screw presses against the contact surface via the washer, The contact surface is provided with a restricting portion that restricts rotation of the washer as the screw is screwed in, The screw is threaded into the mating member with its head passing through a through hole drilled in the fastened member, A screw fastening structure in which the restricting portion interferes with at least one of the teeth of the washer, and rotation of the washer associated with threading of the screw is restricted.

8. 8. A screw fastening structure according to claim 7, wherein the screw is a countersunk head screw having a flat head and a tapered bearing surface, and the washer is a countersunk toothed washer.

9. 9. The screw fastening structure according to claim 7, wherein the fastened members are molded articles made of a resin material.

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