Nut cap

Abstract

A lock plate (20) is received in a guide groove of a body part (10) of a nut cap (1) so as to be slidable in a sliding direction. In an unlocked state, a protrusion (20c) of a first leaf spring (21) engages with a first recess (20a), and the lock plate (20) is held in the unlocked state. An insert nut (11) which is fixed to the body part (10) is screwed to a stud bolt (250), and the nut cap (1) is placed on a wheel nut (240). The lock plate (20) is slid, and a rib part (20r) of the lock plate (20) is brought into contact with a side flat surface part (242) of the wheel nut (240) to restrict the rotation of the nut cap (1) (locked state). In the locked state, the protrusion (20c) of the first leaf spring (21) engages with a first recess (20b), and the lock plate (20) is held in the locked state.

Description

Nut Cap

[0001] The present disclosure relates to a nut cap.

[0002] Conventionally, various components are attached to a main body structure using bolts and nuts. For example, Japanese Patent Application Laid-Open Publication No. 2018-173163 (Patent Document 1) discloses a configuration in which a wheel is fixed to a hub (axle) using a wheel bolt and a wheel nut with a washer.

[0003] Japanese Patent Application Laid-Open Publication No. 2005-329907 (Patent Document 2) discloses a technology that detects wheel detachment in advance and warns the driver based on the detection value of a G sensor that is attached to the wheel and detects acceleration in the axle direction.

[0004] Japanese Utility Model Registration No. 3237357 (Patent Document 3) discloses a nut cap that is placed on a wheel nut. The nut cap in Patent Document 3 is provided with marks at predetermined positions around the periphery of the nut cap, which allows a decrease in the fastening force of the nut to be visually observed.

[0005] JP 2018-173163 A JP 2005-329907 A Utility Model Registration No. 3237357 A

[0006] In the technology described in Patent Document 2, loosening of the bolts or nuts used to attach the wheel to the vehicle body is estimated based on wheel vibrations that occur when the bolts or nuts are not properly tightened or become loose, and wheel detachment is detected in advance.

[0007] However, because the type of wheel vibration that occurs when a bolt or nut loosens varies depending on the type of vehicle and wheel (tire), it can be difficult to accurately estimate the looseness of a bolt or nut. Furthermore, when the looseness is so slight that it does not cause vibration in the wheel, it is difficult to estimate the looseness of the bolt or nut because no vibration occurs in the wheel. For this reason, it is desirable to be able to detect looseness of bolts and nuts regardless of the type of vehicle or wheel, and even when the looseness is relatively slight.

[0008] As in Patent Document 3, it is also useful to use a nut cap to check whether the nut is loose, but there is a risk that the nut cap may fall off the nut due to vibrations of the vehicle, etc.

[0009] An object of the present disclosure is to prevent a nut cap from falling off a nut.

[0010] The nut cap of the present disclosure is a nut cap that is fitted over a nut threaded onto a bolt. The nut cap includes a female threaded portion that threads onto the male threaded portion of the bolt protruding from the nut, and a lock plate that is slidable in the axial direction of the bolt and abuts against the flat side surface of the nut to restrict rotation of the nut cap.

[0011] With this configuration, the nut cap is attached to the nut by threading the female threads of the nut cap onto the male threads of the bolt protruding from the nut. When the lock plate of the nut cap slides in the axial direction of the bolt, the lock plate abuts against the flat side surface of the nut, restricting rotation of the nut cap. Restricting rotation of the nut cap restricts the female threads of the nut cap from rotating in the loosening direction, thereby preventing the nut cap from falling off the nut.

[0012] According to the present disclosure, it is possible to prevent the nut cap from falling off the nut.

[0013] FIG. 1 is a diagram showing a vehicle to which the nut cap of the present embodiment is attached; FIG. 2 is a diagram showing the relationship between each member in the fastening portion of the wheel; FIG. 3 is a perspective view of the nut cap; FIG. 4 is a schematic exploded view of the nut cap; FIG. 5 is a diagram showing the fixing position of the insert nut; FIG. 6 is a schematic perspective view explaining the arrangement of the lock plate; FIG. 7 is a schematic cross-sectional view in the sliding direction including the first leaf spring; FIG. 8 is a schematic cross-sectional view in the sliding direction including the second leaf spring; FIG. 9 is a diagram explaining the functional blocks configured on the substrate; FIG. 10 is a diagram explaining the detection axis of the acceleration sensor; FIG. 11 is a diagram explaining modified examples of the lock plate and the first leaf spring.

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated. The drawings are not drawn according to the actual dimensional ratio, and in some cases, the ratio may be changed to clarify the structure in order to facilitate understanding of the structure.

[0015] 1 is a diagram showing a vehicle 200 to which a nut cap according to the present embodiment is attached. The vehicle 200 includes a plurality of wheels 210. The vehicle 200 also includes a multi-information display 201 that can communicate with a communication unit 53 (described later) and that includes a display unit (not shown).

[0016] The wheel 210 includes a wheel 220 and a tire 230 attached to the wheel 220. The wheel 220 has a wheel hole through which a hub bolt (stud bolt) provided on a hub (axle) of the vehicle 200 is inserted. The wheel 220 is fastened to the hub by threading a plurality of wheel nuts 240 (five in FIG. 1 ) onto the hub bolt (stud bolt). The number of wheel nuts 240 is not limited to the above example, and may be, for example, four, six, eight, or ten.

[0017] Figure 2 is a diagram showing the relationship between the various components in the fastening portion of the wheel 220. The hub is not shown in Figure 2. The wheel 220 is fastened by threading the female thread portion 241 of the wheel nut 240 onto the male thread portion 251 of the stud bolt 250. A wheel hole 221 is formed in the wheel 220. The wheel 220 is fastened by inserting the stud bolt 250 into the wheel hole 221 and threading the wheel nut 240 onto the stud bolt 250. Reference numeral 260 denotes a washer.

[0018] After the wheel 220 is fixed to the hub with the stud bolt 250 and the wheel nut 240, the nut cap 1 is placed over the wheel nut 240 (the nut cap 1 is attached to the wheel nut 240). In this embodiment, the wheel nut 240 is a hexagonal nut, having six side flat portions 242 that form a two-face width, and a top surface 243. The stud bolt 250 corresponds to an example of a "bolt" in this disclosure, and the wheel nut 240 corresponds to an example of a "nut" in this disclosure. The bearing surface of the wheel nut 240 may be a spherical seat without using the washer 260.

[0019] 3 is a perspective view of the nut cap 1. The nut cap 1 includes a main body 10, a lock plate 20, a storage section 30, and a lid 40. The lock plate 20 is provided on the main body 10 so as to be slidable (movable forward and backward).

[0020] 4 is a schematic exploded view of the nut cap 1. The nut cap 1 includes a cylindrical main body 10, a lock plate 20, a storage section 30, and a lid 40. The main body 10 is made of, for example, resin, and an insert nut 11 that screws onto the male threads of the stud bolt 250 is fixed thereto by press-fitting or the like. The insert nut 11 has a female thread 11a that screws onto the male thread 251 of the stud bolt 250. The insert nut 11 may be embedded during molding of the main body 10. The insert nut 11 corresponds to an example of the "female thread" of the present disclosure.

[0021] The cylindrical main body 10 has a side surface (periphery) formed with a guide wall 10g and guide grooves 10a on both sides of the guide wall 10g. The pair of guide grooves 10a are arranged opposite each other and extend in the axial direction (sliding direction) of the main body 10. A guide wall 10g and an opening 10c are formed between the pair of guide grooves 10a. The pair of opposed guide grooves 10a slidably receive a lock plate 20. The lock plate 20 is guided by the guide grooves 10a and slides along the guide wall 10g. When the lock plate 20 is inserted between the pair of guide grooves 10a, movement of the lock plate 20 is restricted in directions other than the sliding direction.

[0022] 5 is a diagram showing the fixing position of the insert nut 11. The insert nut 11 is fixed to the guide wall portion 10g of the main body portion 10 on the opening 10c side.

[0023] Referring again to FIG. 4 , a first recess 20a and a second recess 20b are formed on the surface of the lock plate 20 facing the guide wall 10g. Details of the first recess 20a and the second recess 20b will be described later (hereinafter, the surface of the lock plate 20 facing the guide wall 10g will also be referred to as the “back surface,” and the surface opposite the “back surface” will also be referred to as the “front surface”). A plurality of ribs 20r extending in the sliding direction of the lock plate 20 are formed on the back surface of the lock plate 20. In this embodiment, four ribs 20r are formed, and the ribs 20r formed on both ends of the lock plate 20 are received in the guide groove 10a. The sliding direction is the axial direction of the cylindrical main body 10, which is the axial direction of the stud bolt 250 when the nut cap 1 is attached to the wheel nut 240.

[0024] An operating portion 20s protruding from the surface of the lock plate 20 is formed on the surface of the lock plate 20. The lock plate 20 can be slid by pinching and operating the operating portion 20s with fingers.

[0025] A first leaf spring 21 and a second leaf spring 22 are disposed between the guide wall portion 10g and the lock plate 20. The first leaf spring 21 is fixed to the guide wall portion 10g, and the second leaf spring 22 is fixed to the lock plate 20. The second leaf spring 22 has two spring portions 22a extending from a base portion. Details of the first leaf spring 21 and the second leaf spring 22 will be described later.

[0026] The storage unit 30 is inserted into the main body 10 and fixed to the main body 10. For example, an engagement hole 30b formed in the storage unit 30 engages with an engagement protrusion (not shown) formed on the inner periphery of the main body 10, thereby fixing the storage unit 30 to the main body 10. The storage unit 30 includes a storage space 30a and a cover portion 30c. Devices such as a board 50 equipped with an acceleration sensor 51, an antenna 55, and a battery 56 are housed in the storage space 30a. The battery 56 may be, for example, a button battery. When the storage unit 30 is fixed to the main body 10, the cover portion 30c covers the front side of the lock plate 20, which slides in the guide groove portion 10a (see FIG. 3).

[0027] After the substrate 50 and the like are stored in the storage space 30a, the lid portion 40 is fixed to the storage portion 30 to seal the storage space 30a.

[0028] Figure 6 is a schematic perspective view illustrating the arrangement of the lock plate 20. For ease of explanation, Figure 6 illustrates the insert nut 11, lock plate 20, first leaf spring 21, and second leaf spring 22, while omitting other components. The first leaf spring 21 is fixed to the guide wall portion 10g of the main body 10. The second leaf spring 22 is fixed to the lock plate 20. In Figure 6, the lock plate 20 on the left side illustrates the lock plate 20 in the unlocked state. In Figure 6, the lock plate 20 on the right side illustrates the lock plate in the locked state.

[0029] By rotating the nut cap 1 in the tightening direction, the insert nut 11 is screwed onto the stud bolt 250 protruding from the top surface 243 of the wheel nut 240. When the insert nut 11 abuts against the top surface 243 of the wheel nut 240, the rotation of the nut cap 1 in the tightening direction stops.

[0030] FIG. 7 is a schematic cross-sectional view of the lock plate 20, including the first leaf spring 21, in the sliding direction. In FIG. 7, the lock plate 20 on the left side of the figure is shown in the unlocked state, and the lock plate 20 on the right side of the figure is shown in the locked state. The base of the first leaf spring 21 is fixed to the guide wall 10g of the main body 10. The first leaf spring 21 has an arc-shaped protrusion 21c. The first leaf spring 21 biases the lock plate 20 in a direction that increases the distance between the lock plate 20 and the guide wall 10g (the first leaf spring 21 exerts a resilient force in a direction that increases the distance between the lock plate 20 and the guide wall 10g). In the unlocked state (left side of the figure), the protrusion 21c of the first leaf spring 21 engages with the first recess 20a of the lock plate 20. This restricts the movement of the lock plate 20 in the sliding direction and maintains the unlocked position.

[0031] When the lock plate 20 is held in the unlocked position, the nut cap 1 is rotated in the tightening direction to screw the insert nut 11 onto the stud bolt 250 protruding from the top surface 243 of the wheel nut 240. When the insert nut 11 abuts against the top surface 243 of the wheel nut 240, the rotation of the nut cap 1 in the tightening direction stops.

[0032] The distance L between the rib portions 20r of the two (opposing) lock plates 20 is set to be approximately equal to or slightly larger than the two-face width (the width of the opposing side flat portions 242) of the wheel nut 240 (hexagonal nut). When the insert nut 11 abuts against the top surface 243 of the wheel nut 240, if the side flat portion 242 of the wheel nut 240 and the rib portion 20r of the lock plate 20 are aligned, the operating portion 20s of the lock plate 20 is pinched and the lock plate 20 is slid downward in the figure. The first leaf spring 21 is deflected, disengaging the first recessed portion 20a from the protruding portion 21c. As shown in the locked state on the right side of the figure, the lock plate 20 (rib portion 20r) abuts against the wheel nut 240 (side flat portion 242), restricting rotation of the nut cap 1 (tightening and loosening directions).

[0033] If the side flat portion 242 of the wheel nut 240 and the rib portion 20r of the lock plate 20 are not aligned when the insert nut 11 abuts against the top surface 243 of the wheel nut 240, rotate the nut cap 1 in the loosening direction until the side flat portion 242 and the rib portion 20r (lock plate 20) are aligned. Then, by pinching the operating portion 20s of the lock plate 20 and sliding the lock plate 20 downward in the figure, the lock plate 20 (rib portion 20r) abuts against the wheel nut 240 (side flat portion 242), as shown in the locked state on the right side of the figure, and rotation of the nut cap 1 (in the tightening and loosening directions) is restricted.

[0034] In the locked state (right side in the figure), the convex portion 21c of the first leaf spring 21 engages with the second concave portion 20b of the lock plate 20. This restricts the movement of the lock plate 20 in the sliding direction, and the locked state position is maintained. This configuration corresponds to an example of a "retaining portion" in the present disclosure.

[0035] To remove the nut cap 1 from the wheel nut 240, pinch the operating portion 20s of the lock plate 20 and slide the lock plate 20 upward in the illustration. This puts the nut cap 1 in an unlocked state, allowing it to be rotated in the loosening direction. In the unlocked state, rotating the nut cap 1 in the loosening direction releases the threaded engagement between the insert nut 11 and the stud bolt 250, allowing the nut cap 1 to be removed from the wheel nut 240.

[0036] FIG. 8 is a schematic cross-sectional view in the sliding direction, including the second leaf spring 22. In FIG. 8, the lock plate 20 on the left side of the illustration is in an unlocked state, and the lock plate 20 on the right side of the illustration is in a locked state. FIG. 8 also shows a schematic cross-section of one of the two spring portions 22a of the second leaf spring 22. The base of the second leaf spring 22 is fixed to the lock plate 20. The second leaf spring 22 (spring portion 22a) is formed with an abutment portion 22c. The second leaf spring 22 biases the lock plate 20 in a direction that widens the distance between the lock plate 20 and the guide wall portion 10g (the second leaf spring 22 is exerted with a resilient force in a direction that widens the distance between the lock plate 20 and the guide wall portion 10g). In the unlocked state shown on the left side of the illustration, the abutment portion 22c of the second leaf spring 22 abuts against the guide wall portion 10g.

[0037] When the lock plate 20 slides and transitions to the locked state, the second leaf spring 22 slides integrally with the lock plate 20, and as shown on the right side of the figure, the abutting portion 22c of the second leaf spring 22 abuts against the side flat portion 242 of the wheel nut 240. When the abutting portion 22c abuts against the side flat portion 242, the lock plate 20 receives a biasing force (resilient force) in a direction that widens the gap between the lock plate 20 and the side flat portion 242. This biasing force (resilient force) is transmitted to the guide groove portion 10a of the main body 10 via the lock plate 20. As a result, in the locked state, the second leaf spring 22 abuts against the side flat portion 242 of the wheel nut 240 and biases the lock plate 20 radially outward from the wheel nut 240, thereby suppressing rattling of the nut cap 1. In this embodiment, the lock plate 20 and the second leaf spring 22 are arranged to sandwich the two-face width (opposing side flat portions 242) of the wheel nut 240, thereby effectively suppressing rattle of the nut cap.

[0038] 4, the storage space 30a of the storage unit 30 stores devices such as a circuit board 50 equipped with an acceleration sensor 51, an antenna 55, and a battery 56. Fig. 9 is a diagram illustrating functional blocks configured on the circuit board 50. The functional blocks include the acceleration sensor 51, a processing unit 52, a communication unit 53, and a power supply unit 54.

[0039] The acceleration sensor 51 may be, for example, a capacitance type acceleration sensor. In this embodiment, the acceleration sensor 51 has two detection axes, and detects the magnitude of acceleration applied to the detection axes and the direction of the acceleration applied to the detection axes as a positive / negative sign.

[0040] 10 is a diagram illustrating the detection axes of the acceleration sensor 51. When the nut cap 1 is attached to the wheel nut 240, the acceleration sensor 51 detects accelerations along the X-axis and Y-axis, which are perpendicular to each other in a plane perpendicular to the rotation axis O of the wheel 220 (the axis (horizontal axis) extending in a direction perpendicular to the paper surface of FIG. 10). The detection axis of the acceleration sensor 51 may be a single axis (for example, the X-axis).

[0041] The processing device 52 determines the fastening state of the wheel nut 240 based on the detection signal of the acceleration sensor 51. The processing device 52 may include, for example, a central processing unit (CPU) and memory (not shown). The processing device 52 determines the fastening state of the wheel nut 240 by calculating the rotation angle of the wheel nut 240 in the loosening direction based on the X-axis acceleration Gx, Y-axis acceleration Gy, and the rotational speed of the wheel 210 detected by the acceleration sensor 51. When the lock plate 20 is in the locked state, the nut cap 1 attached to the wheel nut 240 rotates integrally with the wheel nut 240 (in the tightening and loosening directions). Therefore, the fastening state of the wheel nut 240 can be determined based on the detection signal of the acceleration sensor 51 mounted on the nut cap 1.

[0042] The communication unit 53 transmits the processing results of the processing device 52 or information based on the processing results to the multi-information display 201 ( FIG. 1 ) of the vehicle 200 via wireless communication via the antenna 55. The power supply unit 54 supplies power from the battery 56 to each of the acceleration sensor 51, the processing device 52, and the communication unit 53. The processing device 52 may have a function to transmit the accelerations Gx and Gy detected by the acceleration sensor 51 from the communication unit 53 to the vehicle 200 at predetermined intervals. In this case, the fastening state of the wheel nuts 240 may be determined by a processing device mounted on the vehicle 200.

[0043] According to this embodiment, the nut cap 1 is attached by covering the wheel nut 240 that is threaded onto the stud bolt 250. The nut cap 1 includes a female thread portion 11a that threads onto a male thread portion 251 of the stud bolt 250 that protrudes from the wheel nut 240, and a lock plate 20 that is slidable in the axial direction of the stud bolt 250 and abuts against a flat side surface portion 242 of the wheel nut 240 to restrict rotation of the nut cap 1.

[0044] The nut cap 1 is attached to the wheel nut 240 by threading the female thread portion 11a of the nut cap 1 onto the male thread portion 251 of the stud bolt 250 protruding from the wheel nut 240. When the lock plate 20 of the nut cap 1 slides in the axial direction of the stud bolt 250, the lock plate 20 comes into contact with the side flat portion 242 of the wheel nut 240, restricting rotation of the nut cap 1. Restricting the rotation of the nut cap 1 restricts the female thread portion 11a of the nut cap 1 from rotating in the loosening direction, thereby preventing the nut cap 1 from falling off the wheel nut 240.

[0045] In this embodiment, the fastening state of the wheel nut 240 is determined by the detection signal of the acceleration sensor 51 mounted on the nut cap 1. If the lock plate 20 of the nut cap 1 is unlocked and the female thread portion 11a of the nut cap 1 rotates in the loosening direction, the nut cap 1 may fall off the wheel nut 240. In this case, the loosening of the female thread portion 11a of the nut cap 1 can be detected by the detection signal of the acceleration sensor 51, just as in the determination of the fastening state of the wheel nut 240. Therefore, it is possible to predict the possibility of the nut cap 1 falling off and prevent the nut cap 1 from falling off.

[0046] [Modification] Figure 11 is a diagram illustrating a modification of the lock plate and first leaf spring. Figure 11 corresponds to the schematic cross-sectional view of Figure 7. The modified lock plate 20A has a first magnet 81 and a second magnet 82 instead of the first recess 20a and the second recess 20b of the lock plate 20 in the above embodiment. The first magnet 81 is fixed to a position corresponding to the first recess 20a of the lock plate 20, and the second magnet 82 is fixed to a position corresponding to the second recess 20b.

[0047] The retaining plate 71 of the modified example is a member that replaces the first leaf spring 21 in the above embodiment. The base of the retaining plate 71 is fixed to the guide wall portion 10g of the main body portion 10. A third magnet 71c is fixed to the retaining plate 71 at a position corresponding to the protrusion 21c of the first leaf spring 21. The first magnet 81 and the third magnet 71c are arranged with their north and south poles facing each other so as to attract each other. The second magnet 82 and the third magnet 71c are arranged with their north and south poles facing each other so as to attract each other. In the unlocked state (left side in the figure), the first magnet 81 and the third magnet 71c are attracted to each other, restricting the movement of the lock plate 20 in the sliding direction and maintaining the unlocked state position.

[0048] In the locked state (right side in the figure), the second magnet 82 and the third magnet 71c are attracted to each other, restricting the movement of the lock plate 20 in the sliding direction and maintaining the locked position. This configuration corresponds to an example of the "retaining portion" of the present disclosure.

[0049] In the above embodiment, the insert nut 11 is used to thread the nut cap 1 (main body 10) onto the stud bolt 250. However, it is also possible to form a female thread portion on the main body 10 without using the insert nut 11, for example.

[0050] In the above embodiment, the main body 10 is provided with two lock plates 20, but the number of lock plates 20 may be one.

[0051] In the above embodiment, in the locked state, the rib portion 20r of the lock plate 20 abuts against the side flat portion 242 of the wheel nut 240. However, this is not limiting, and another part of the lock plate 20 or a member fixed to the lock plate 20 may abut against the side flat portion 242 of the wheel nut 240 in the locked state.

[0052] In the above embodiment, the acceleration sensor 51 (substrate 50) is stored in the storage space 30a of the storage unit 30, and the detection signal from the acceleration sensor 51 makes it possible to detect loosening of the female thread portion 11a of the nut cap 1 and predict signs of detachment of the nut cap 1. However, the sensor mounted on the nut cap 1 does not have to be an acceleration sensor. For example, a magnet may be fixed to the tip surface of the stud bolt 250 so that it has a north pole and a south pole in a direction intersecting the axial direction of the stud bolt 250, and a magnetic sensor that detects the magnetic field generated by the magnet at the tip of the stud bolt 250 may be disposed in the storage unit 30 of the nut cap 1. With this configuration, when the nut cap 1 rotates and the magnetic sensor rotates, the magnetic flux density applied to the magnetic sensor (magnetic flux density due to the magnetic field of the magnet) changes, causing a change in the output signal of the magnetic sensor, making it possible to detect loosening of the female thread portion of the nut cap 1.

[0053] In the above embodiment, an example has been described in which the nut cap 1 is attached to the wheel nut 240, but the nut to which the nut cap 1 is attached is not limited to the wheel nut 240 and may be any nut. Also, although the nut cap 1 is equipped with devices such as the substrate 50, these devices do not have to be equipped.

[0054] The following aspects can be exemplified as embodiments of the present disclosure.

[0055] 1) A nut cap (1) that is placed over a nut (240) threaded onto a bolt (250), and that includes: a female threaded portion that threads onto the male threaded portion of the bolt (250) protruding from the nut (240); and a lock plate (20) that is slidable in the axial direction of the bolt (250) and abuts against the side flat portion (242) of the nut (240) to restrict rotation of the nut cap (1).

[0056] 2) In the above 1, the nut cap further includes a retaining portion that retains the position of the lock plate (20) in the sliding direction when the lock plate (20) is slid to a position that restricts the rotation of the nut cap (1).

[0057] With this configuration, when the lock plate is slid to a position that restricts rotation of the nut cap (when in the locked state), the position of the lock plate in the sliding direction is maintained, thereby preventing the lock plate from unintentionally sliding to a position that allows rotation of the nut cap (the unlocked state).

[0058] 3) In the above 1 and 2, a nut cap further comprising a biasing member (22) that abuts against a side flat portion (242) of the nut (240) and biases the lock plate (20) radially outward from the nut (240) when the lock plate (20) is slid to a position that restricts rotation of the nut cap (1).

[0059] According to this configuration, rattle of the nut cap can be suppressed by the biasing force of the biasing member.

[0060] 4) In the above 1 to 3, the nut (240) is a hexagonal nut, and two lock plates (20) are provided so as to abut against the parallel side flat portions (242) of the hexagonal nut.

[0061] According to this configuration, the lock plate is arranged to sandwich the flat portion of the hexagonal nut, so that the rotation of the nut cap can be stably restricted.

[0062] 5) A nut cap according to any one of 1 to 4 above, further comprising a main body (10) that slidably holds the lock plate (20), and the female threaded portion (11) is formed separately from the main body (10) and fixed to the main body (10).

[0063] With this configuration, even if the main body of the nut cap is formed from resin or the like, a metal female thread portion can be used, for example, making it possible to firmly screw the nut cap into the bolt.

[0064] 6) In the above 1 to 5, a nut cap further comprising a sensor capable of detecting the rotation of the nut cap (1).

[0065] According to this configuration, by detecting the rotation of the nut cap, it is possible to detect the possibility that the nut cap will fall off the nut.

[0066] 7) In the above 6, the sensor is an acceleration sensor (51), nut cap.

[0067] 8) The nut cap according to 6 or 7 above, further comprising a transmitter for transmitting the detection result of the sensor.

[0068] According to this configuration, it is possible to detect the possibility that the nut cap will fall off the nut based on the detection result transmitted from the transmitter.

[0069] 9) In the above 1 to 4, a nut cap further comprising a main body (10) that slidably holds the lock plate (20), a sensor that can detect the rotation of the nut cap (1), and a storage section (30) that stores the sensor and is fixed to the main body (10), wherein the female thread section (11) is formed separately from the main body (10) and is fixed to one side of the main body (10) in the axial direction, and the storage section (30) is fixed to the other side of the main body (10) in the axial direction.

[0070] According to this configuration, the sensor is stored in the storage section fixed to the other side of the main body, so that the sensor can be mounted on the nut cap relatively easily.

[0071] The embodiments disclosed herein are merely examples and are not limited to the above. The scope of the present invention is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0072] 1 Nut cap, 10 Main body, 10a Guide groove portion, 10g Guide wall portion, 11 Insert nut, 11a Female thread portion, 20 Lock plate, 20a First recess, 20b Second recess, 21 First leaf spring, 22 Second leaf spring, 30 Storage portion, 30a Storage space, 30c Cover portion, 40 Lid portion, 50 Board, 51 Acceleration sensor, 53 Communication portion, 55 Antenna, 56 Battery, 200 Vehicle, 210 Wheel, 220 Wheel, 240 Wheel nut, 250 Stud bolt, 251 Male thread portion, 260 Washer.

Claims

1. A nut cap that is placed over a nut threaded onto a bolt, the nut cap having a female threaded portion that screws onto the male threaded portion of the bolt protruding from the nut, and a lock plate that is slidable in the axial direction of the bolt and abuts against the flat side surface of the nut to restrict rotation of the nut cap.

2. A nut cap as described in claim 1, further comprising a retaining portion that retains the position of the lock plate in the sliding direction when the lock plate is slid to a position that restricts rotation of the nut cap.

3. A nut cap as described in claim 1, further comprising a biasing member that abuts against the side flat portion of the nut when the locking plate is slid to a position that restricts rotation of the nut cap, and biases the locking plate radially outward from the nut.

4. A nut cap according to any one of claims 1 to 3, wherein the nut is a hexagonal nut, and two lock plates are provided so as to abut against the parallel side flat portions of the hexagonal nut.

5. The nut cap according to claim 1, further comprising a main body portion that slidably holds the lock plate, and the female thread portion is formed separately from the main body portion and fixed to the main body portion.

6. The nut cap according to any one of claims 1 to 3, further comprising a sensor capable of detecting rotation of the nut cap.

7. The nut cap according to claim 6, wherein the sensor is an acceleration sensor.

8. The nut cap according to claim 6, further comprising a transmitter that transmits the detection result of the sensor.

9. A nut cap as described in any one of claims 1 to 3, further comprising: a main body portion that slidably holds the lock plate; a sensor that can detect rotation of the nut cap; and a storage portion that houses the sensor and is fixed to the main body portion, wherein the female thread portion is formed separately from the main body portion and is fixed to one side of the main body portion in the axial direction, and the storage portion is fixed to the other side of the main body portion in the axial direction.

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