Wheel nut loosening prevention device

Abstract

Provided is a wheel nut loosening prevention device capable of suppressing a reduction in axial force of a wheel bolt due to rotation loosening of a wheel nut without requiring expensive modification costs even when used in an existing large automobile. This wheel nut loosening prevention device comprises: a base plate 20 which is attached to at least two wheel nuts 19 adjacent to each other, and in which oscillation with any one of the wheel nuts as an oscillation center is restricted; and lock plates 30 into which the respective wheel nuts 19 are inserted regardless of a rotation angle with respect to a shaft part 5a of a wheel bolt 5, and which is attached to the base plate 20 so as not to be relatively rotatable, the lock plate contacting a side surface 19d of the wheel nut 19 rotating in a loosening direction to thereby restrict the rotation in the loosening direction to a loosening angle of an allowable angle or lower.

Description

Wheel nut loosening prevention device

[0001] This invention relates to a wheel nut loosening prevention device.

[0002] Large vehicles such as medium-sized trucks, heavy-duty trucks, and tour buses are equipped with multiple pairs of hubs and multiple pairs of wheels fixed to each hub. Each hub is secured by six, eight, or ten wheel bolts, with the shafts of each wheel bolt protruding horizontally outward from the vehicle. Each wheel is fitted with a tire to form a wheel. Each wheel has the same number of wheel bolt holes as there are wheel bolts, and the shafts of each wheel bolt are inserted into the wheel bolt holes and screwed in by wheel nuts. In this way, the wheels are fixed to each hub.

[0003] In recent years, there has been an increase in accidents involving large vehicles where a wheel nut loosens while driving, causing the wheel to detach. Left-side wheels are particularly prone to detachment, and double-wheeled vehicles appear to be even more susceptible.

[0004] Patent documents 1 to 3 below propose nut loosening prevention devices for vehicles.

[0005] The wheel nut loosening prevention device described in Patent Document 1 comprises a metal cable tie that is wrapped around wheel nuts screwed onto multiple wheel bolts. An engagement groove extending along the direction of nut rotation is formed on the outer surface of each wheel nut. The cable tie is wrapped in a loop around multiple wheel nuts, which are arranged at equal intervals along the circumferential direction of the wheel, from the radially outward direction of the wheel. In this way, the cable tie, which fits into the engagement groove of each wheel nut, prevents the rotation of each wheel nut from loosening.

[0006] The nut loosening prevention device described in Patent Document 2 is a nut loosening prevention device for fastening a power transmission shaft to a companion flange, and comprises a metal ring plate with an external gear formed on its outer circumference and a metal case with an internal gear formed on its inner circumference. The ring plate has two projections on its inner circumference that engage with a rotation-preventing notch formed on the tip surface of the shaft. The case has engaging claws that engage with an engagement groove formed on the outer circumference of the nut. The ring plate is inserted onto the shaft from above the nut and fixed to the shaft by the two projections engaging with the notch on the shaft. The case is fitted onto the outer circumference of the ring plate by the meshing of the external gear and the internal gear, and the engaging claws engage with the engagement groove and are fixed to the nut. In this way, the shaft, ring plate, case and nut are integrated by the engagement of the notch and projections, the meshing of the external gear and the internal gear, and the engagement of the engaging claws and the engagement groove. This prevents the nut from rotating loose.

[0007] The wheel nut loosening prevention device described in Patent Document 3 comprises a base member attached to two adjacent wheel nuts among a plurality of wheel nuts, and a locking member attached to each wheel nut. The locking member has a lock insertion hole through which the wheel nut is inserted and which at least a portion of the wheel nut abuts. The lock insertion hole has six inner surfaces of lock holes corresponding to the six sides of the wheel nut. As a result, the contact between the sides of the wheel nut and the inner surfaces of the locking holes of the locking member makes it substantially impossible for the locking member to rotate relative to the wheel nut. The base member has two base insertion holes through which each locking member is inserted. The inner circumferential surface of each base insertion hole has a base uneven surface formed in which recesses and protrusions are arranged alternately in the circumferential direction. The outer circumferential surface of each locking member also has a lock uneven surface formed in which recesses and protrusions are arranged alternately in the circumferential direction. The height difference and spacing of the unevenness in the lock uneven surface are smaller than the height difference and spacing of the unevenness in the base uneven surface. Furthermore, each locking member is C-ring shaped with a notch at one point in the circumferential direction. In this wheel nut loosening prevention device, each locking member attached to each wheel nut is fitted into each base insertion hole of the base member, causing the locking protrusions and recesses to come into contact with the base protrusions and recesses. This makes it difficult for each locking member to rotate within each base insertion hole, which is said to allow for highly reliable prevention of wheel nut loosening.

[0008] Japanese Patent Publication No. 7115713 Japanese Patent Publication No. 5832883 Japanese Design Registration Publication No. 1708558

[0009] However, the wheel nut loosening prevention device described in Patent Document 1 above has a structure that prevents the rotation of the wheel nut by frictional force between the cable tie and the outer surface of the wheel nut, making it difficult to reliably prevent the wheel nut from loosening. Furthermore, if the frictional force with the cable tie decreases, the wheel nut will rotate indefinitely. As a result, the axial force of the wheel bolt decreases, which reduces the frictional force between the wheel and the hub, causing the wheel to become loose. When loads such as the weight of the vehicle are applied to the wheel bolt, the wheel bolt may break or the wheel nut may fall off, making the wheel more likely to come off.

[0010] The nut loosening prevention device described in Patent Document 2 requires a notched shape on the tip surface of the shaft. Therefore, if this loosening prevention device is applied to an existing large vehicle to prevent wheel nuts from loosening, the wheel bolts will need to be replaced, resulting in high modification costs.

[0011] Furthermore, in the wheel nut loosening prevention device of Patent Document 3, the protrusions of the locking protrusions do not fit into the recesses of the base protrusions, and the base protrusions and the locking protrusions are not in a so-called interlocking fit. In other words, this wheel nut loosening prevention device has a structure that prevents the wheel nut from rotating loosening by the frictional force generated by the contact between the base protrusions and the locking protrusions, which have a smaller height difference and spacing than the base protrusions, and therefore has the same problems as the wheel nut loosening prevention device of Patent Document 1. Moreover, in this wheel nut loosening prevention device, since the locking member is in the shape of a C-ring with a notch, the rigidity of the locking member cannot be used to counteract the rotational force of the wheel nut. For this reason, there is a concern that the base member and other parts may deform.

[0012] This invention has been made in view of the above-mentioned conventional circumstances, and aims to solve the problem of providing a wheel nut loosening prevention device that does not require high modification costs even when used in existing large automobiles, and that can suppress the decrease in axial force of wheel bolts due to the rotational loosening of wheel nuts.

[0013] The wheel nut loosening prevention device of the present invention is a wheel nut loosening prevention device that is attached to a plurality of wheel nuts of a large vehicle to suppress the rotational loosening of at least one of the wheel nuts, wherein the large vehicle comprises a hub to which a plurality of wheel bolts are fixed and the shaft portion of each wheel bolt protrudes, and a wheel to which a tire is assembled to constitute a wheel, wherein the same number of wheel bolt holes as the wheel bolts are provided through the wheel, and the shaft portion of each is inserted through each of the wheel bolt holes and screwed in by each of the wheel nuts, thereby being fixed to the hub, and wherein the device comprises a base plate attached to at least two adjacent wheel nuts, which restricts the oscillation with any of the wheel nuts as the pivot point, and a lock plate through which each of the wheel nuts is inserted regardless of the rotation angle with respect to the shaft portion and which is mounted so as not to rotate relative to the base plate, and which contacts the side surface of the wheel nut that rotates in the loosening direction, thereby restricting the rotation in the loosening direction to a loosening angle below an allowable angle.

[0014] In the wheel nut loosening prevention device of the present invention, a lock plate is mounted on a base plate attached to at least two adjacent wheel nuts so as not to rotate relative to the wheel nut. When the wheel nut rotates in the loosening direction in this mounted state, the contact between the side of the wheel nut and the lock plate restricts the rotation in the loosening direction to a loosening angle below the allowable angle. Therefore, in wheel nuts to which the base plate and lock plate are mounted, rotational loosening that exceeds the allowable angle can be prevented. As a result, the reduction in the axial force of the wheel bolt caused by the rotational loosening of the wheel nut can be suppressed.

[0015] Furthermore, the wheel nut loosening prevention device of the present invention can be used as is on existing large vehicles without requiring the replacement of wheel bolts, thus eliminating the need for expensive modifications.

[0016] Therefore, the wheel nut loosening prevention device of the present invention does not require expensive modification costs even when used on existing large automobiles, and can suppress the decrease in axial force of wheel bolts due to the rotational loosening of wheel nuts.

[0017] In the wheel nut loosening prevention device of the present invention, the shaft portion may be formed around the axis. Preferably, the base plate has a base insertion hole through which each wheel nut is inserted, centered on a base axis that coincides with each axis, and a base uneven portion formed on the inner circumferential surface of each base insertion hole and uniformly formed around the base axis. Preferably, each lock plate has a lock insertion hole through which each wheel nut is inserted, centered on a lock axis that coincides with each axis, while defining the loosening angle to an allowable angle, and a lock uneven portion formed on the outer circumferential surface that fits with the base uneven portion so as to be mounted to the base plate in a way that prevents relative rotation.

[0018] In this case, the interlocking of the base's protrusions and recesses with the lock's protrusions ensures that the lock plate is reliably prevented from rotating relative to the base plate.

[0019] In the wheel nut anti-loosening device of the present invention, the base uneven portion may have n peaks and n valleys arranged alternately around the base axis, and the lock uneven portion may have n peaks and n valleys arranged alternately around the lock axis. Preferably, the lock insertion hole is formed with a right-hand contact portion and a left-hand contact portion that contact the side surface of the wheel nut as the wheel nut rotates clockwise and counterclockwise relative to the lock plate. Furthermore, when the rotation angle of the wheel nut in the clockwise direction relative to the lock plate through which the wheel nut is inserted is R, and the rotation angle of the wheel nut in the counterclockwise direction relative to the lock plate is L, the allowable angle is the sum of the rotation angles R and L, and is preferably shown by the following equations (1) and (2): R + L = A …(1) 360 / n ≤ A …(2)

[0020] In this case, the base protrusions are formed evenly around the base axis by n peaks and n valleys. Similarly, the lock protrusions are formed evenly around the lock axis by n peaks and n valleys. This reliably prevents the wheel nut from rotating beyond the allowable angle A in the direction that would loosen it. Furthermore, the allowable angle represented by A in equation (2) above is set to be large enough to be 360 / n or more, which is the angle of one peak or valley in the lock protrusions. That is, the wheel nut can rotate within the lock insertion hole at an angle of 360 / n or more, which is the angle of one peak or valley in the lock protrusions. Therefore, by inserting the wheel nut, which has been inserted through the base plate, into the lock insertion hole, and rotating the lock plate by an angle smaller than 360 / n, which is the angle of one peak or valley in the lock protrusions, the base protrusions and the lock protrusions can be engaged. As a result, regardless of the angle at which the wheel nut fastened to the wheel bolt is positioned relative to the base plate, the wheel nut can be inserted through the lock insertion hole, and the lock plate can be attached to the base plate by engaging the recessed and recessed parts of the base and the lock with each other.

[0021] In the wheel nut loosening prevention device of the present invention, the lock plate is preferably annular in shape. Furthermore, the lock insertion hole is preferably having an inner surface corresponding to each side of the wheel nut. Furthermore, each inner surface of the lock hole is preferably having a right-hand contact portion and a left-hand contact portion. In addition, it is preferable that adjacent inner surfaces of lock holes in the circumferential direction are connected by a connecting portion.

[0022] In this case, the rotational force from the wheel nut that has become loose can be received by the annular lock plate, which is fixed to the base plate, which is fixed to the wheel nut, in a way that prevents rotation. Therefore, the load from the wheel nut can be withstood by the tensile force of the annular lock plate and the base plate. As a result, deformation of the lock plate and the base plate can be suppressed with high reliability. Furthermore, if the inner surfaces of adjacent lock holes in the circumferential direction are connected to form a corner, the strength of that part may decrease. However, if the inner surfaces of the lock holes are connected by a connecting part, the decrease in strength due to the formation of a sharp corner can be suppressed.

[0023] The wheel nut loosening prevention device of the present invention preferably includes a stopper member that holds the base plate and the lock plate.

[0024] In this case, the stopper member can reliably prevent the base plate and lock plate from falling off the wheel nut.

[0025] The wheel nut loosening prevention device of the present invention preferably comprises a top ring that covers all base plates and all lock plates, having multiple top insertion holes through which all of the multiple wheel nuts are inserted, and a stopper member that holds the top ring.

[0026] In this case, the stopper member can reliably prevent the top ring from falling off the wheel nut, and consequently, it can reliably prevent all base plates and all lock plates from falling off the wheel nut. Furthermore, even if a flying object hits the stopper member and causes it to fall off while driving, or if the stopper member hits a fixed object on the road and causes it to fall off, the remaining stopper member can prevent the top ring from falling off the wheel nut, and consequently, it can reliably prevent all base plates and all lock plates from falling off the wheel nut.

[0027] In the wheel nut loosening prevention device of the present invention, it is preferable that each lock plate has a restricting portion that protrudes toward the hub side in the thickness direction of the lock plate, then extends radially outward relative to the shaft portion, and abuts against the base plate to restrict the movement of the base plate toward the hub side.

[0028] In this case, the base plate's movement toward the hub is restricted by the restricting mechanism. Therefore, the secure attachment of the lock plate to the base plate can be maintained with high reliability.

[0029] The wheel nut loosening prevention device of the present invention preferably comprises: an arrow-shaped fixing ring that is mounted on the wheel nut so as not to rotate relative to it, having a fixing ring insertion hole through which the wheel nut is inserted coaxially, and through which the fixing ring axis is inserted, and through which the wheel nut is inserted, through which the arrow plate is inserted, having an arrow plate insertion hole through which the wheel nut is inserted coaxially, and through which the arrow plate is mounted on the arrow-shaped fixing ring so as not to rotate relative to it, and a stopper member that holds the arrow-shaped fixing ring and the arrow plate. Preferably the arrow-shaped fixing ring has a fixing ring recessed portion in which m peaks and m valleys are arranged alternately around the fixing ring axis. Preferably the arrow-shaped plate has an arrow-shaped recessed portion in which m peaks and m valleys are arranged alternately around the arrow axis and through which the recessed portion of the fixing ring fits recessed.

[0030] In this case, the wheel nut is inserted through the fixing ring insertion hole, and the arrow fixing ring is attached to the wheel nut. At the same time, the wheel nut is inserted through the arrow plate insertion hole, and the arrow plate is held in place by the arrow fixing ring so that it cannot rotate relative to it. As a result, the arrow plate rotates integrally with the wheel nut together with the arrow fixing ring. Therefore, the loosening of the wheel nut can be visually detected by the displacement of the arrow plate from its predetermined position. Furthermore, the interlocking of the protrusions and recesses of the fixing ring and the arrow plate allows the arrow plate to be held in place so that it cannot rotate relative to the arrow fixing ring. The orientation of the arrow plate attached to the wheel nut can be easily fine-tuned by setting the number of peaks and valleys in the interlocking protrusions and recesses of the fixing ring and the arrow plate.

[0031] The wheel nut loosening prevention device of the present invention does not require expensive modification costs even when used on existing large automobiles, and it can suppress the decrease in axial force of wheel bolts due to the rotational loosening of wheel nuts.

[0032] Figure 1 is a side view of a large truck equipped with the wheel nut loosening prevention device according to Examples 1 to 4. Figure 2 is a side view of a wheel to which the wheel nut loosening prevention device according to Examples 1 to 4 is attached. Figure 3 is an exploded perspective view of a double wheel on a large truck. Figure 4 is an exploded perspective view of the wheel nut loosening prevention device according to Example 1, showing the washer, base plate, lock plate, top ring, arrow fixing ring, arrow plate, and push nut, etc., attached to the wheel nut. Figure 5 is a plan view of the lock plate according to the wheel nut loosening prevention device according to Example 1. Figure 6 is a partial plan view of the lock plate according to the wheel nut loosening prevention device according to Example 1. Figure 7 is a partial enlarged view of the lock plate in Figure 6 according to the wheel nut loosening prevention device according to Example 1. Figure 8 is a partial enlarged view of the lock plate in Figure 6 according to the wheel nut loosening prevention device according to Example 1. Figure 9 is a perspective view relating to the wheel nut loosening prevention device in Example 1, showing a washer and part of the base plate attached to the wheel nut, and the lock plate before being attached to the wheel nut. Figure 10 is a plan view relating to the wheel nut loosening prevention device in Example 1, showing the base plate and lock plate attached to the wheel nut. Figure 11 is a perspective view relating to the wheel nut loosening prevention device in Example 1, showing the arrow fixing ring, arrow plate, and push nut. Figure 12 is a perspective view relating to the wheel nut loosening prevention device in Example 2, showing the wheel nut, part of the top ring, arrow fixing ring, arrow plate, and C ring. Figure 13 is a perspective view relating to the wheel nut loosening prevention device in Example 3, showing the wheel nut, part of the top ring, arrow plate, double-sided tape, and push nut. Figure 14 is an exploded perspective view relating to the wheel nut loosening prevention device in Example 4, showing the lock plate, base plate, top ring, arrow fixing ring, arrow plate, and push nut, etc., attached to the wheel nut. Figure 15 is a perspective view showing the lock plate of the wheel nut loosening prevention device in Embodiment 4. Figure 16 is a plan view of the lock plate of the wheel nut loosening prevention device in Embodiment 4.Figure 17 is a plan view relating to the wheel nut loosening prevention device in Embodiment 4, showing a part of the base plate and the lock plate attached to the wheel nut. Figure 18 is a perspective view relating to the wheel nut loosening prevention device in Embodiment 4, showing a part of the base plate and the lock plate attached to the wheel nut. Figure 19 is a perspective view relating to the wheel nut loosening prevention device in Embodiment 4, showing the arrow fixing ring and the arrow plate.

[0033] Examples 1 to 4 that embody the present invention will be described below with reference to the drawings.

[0034] (Example 1) The wheel nut loosening prevention device 100 in Example 1 (hereinafter referred to as "loosening prevention device" as appropriate) is mounted on a large truck 1 shown in Figure 1.

[0035] Large truck 1 has front wheels Wf, a first rear wheel Wr1, and a second rear wheel Wr2 on the left and right sides, respectively. Large truck 1 is an example of a "large vehicle" in the present invention. Large truck 1 is equipped with six anti-loosening devices 100. Specifically, the anti-loosening devices 100 are provided on the right front wheel Wf, the left front wheel Wf, the right first rear wheel Wr1, the left first rear wheel Wr1, the right second rear wheel Wr2, and the left second rear wheel Wr2 of the vehicle, respectively.

[0036] The large truck 1 is equipped with hubs 3a for the front wheels, hub 3b for the first rear wheel, and hub 3c for the second rear wheel, on both the left and right sides. As shown in Figure 2, eight wheel bolts 5 conforming to the new ISO standard are fixed to each of the hubs 3a to 3c. The shaft portion 5a of each wheel bolt 5 protrudes horizontally outward from the vehicle. Each wheel bolt 5 was originally installed on the large truck 1.

[0037] Wheels 7a are fixed to both hubs 3a. In other words, the front wheel Wf is a single wheel. The inner wheel 7b and the outer wheel 7c are fixed to both hubs 3b, and the inner wheel 7d and the outer wheel 7e are fixed to both hubs 3c. In other words, the first rear wheel Wr1 and the second rear wheel Wr2 are double wheels.

[0038] As shown in FIG. 3, in the first rear wheel Wr1 as a double wheel, an inner wheel W1 and an outer wheel W2 are sequentially attached to one hub 3b. The inner wheel W1 is configured by assembling a tire 9a to an inner wheel 7b. Similarly, the outer wheel W2 is configured by assembling a tire 9b to an outer wheel 7c.

[0039] The inner wheel 7b has a hub attachment portion 13a attached to the hub 3b. The hub attachment portion 13a is provided with wheel bolt holes 13b equal in number to the wheel bolts 5. Note that the hub attachment portion 13a of the inner wheel 7b protrudes toward the outside of the vehicle body. The outer wheel 7c has a hub attachment portion 15a attached to the hub 3b. The hub attachment portion 15a is also provided with wheel bolt holes 15b equal in number to the wheel bolts ⑤. Note that the hub attachment portion 15a of the outer wheel 7c protrudes toward the inside of the vehicle body. Wheel nuts 19 are screwed onto the shaft portions 5a of the respective wheel bolts 5 inserted through the wheel bolt holes 13b of the inner wheel 7b and the wheel bolt holes 15b of the outer wheel 7c. Thus, the inner wheel W1 and the outer wheel W2 are fixed to one hub 3b, and the first rear wheel Wr1 is configured. The wheel nut 19 was originally provided on the large truck 1. The same applies to the second rear wheel Wr2.

[0040] FIG. 3 shows an example of a double wheel, and the same applies to the front wheel Wf as a single wheel. The hub attachment portion of the wheel 7a of the front wheel Wf is provided with wheel bolt holes equal in number to the wheel bolts 5. Thus, the shafts 5a of the wheel bolts 5 are inserted through the wheel bolt holes 13b and 15b of the wheels 7a to 7e, respectively. The wheels 7a to 7e were also originally provided on the large truck 1 together with the tires 9a and 9b.

[0041] As shown in FIG. 4, the anti-loosening device 100 is attached to eight wheel nuts 19 screwed onto the shaft portions 5a of the eight wheel bolts 5. Each wheel nut 19 has the same configuration.

[0042] As shown in FIG. 4 and the like, the wheel nut 19 is a metal hexagonal nut having a nut base portion 19a and a nut main body portion 19b. A nut washer portion is caulked to the nut base portion 19a in a rotatable state. The back surface of the nut washer portion in the nut base portion 19a directly abuts on the wheels 7a to 7e. Further, the wheel nut 19 has a nut insertion hole 19c through which the axis X of the shaft portion 5a of the wheel bolt 5 is coaxially inserted. That is, the nut axis of the nut insertion hole 19c in the wheel nut 19 coincides with the axis X of the shaft portion 5a inserted through the nut insertion hole 19c. Although illustration is omitted, a female screw portion that engages with the male screw portion formed on the shaft portion 5a is formed in the nut insertion hole 19c.

[0043] In FIG. 4, only the tip of the shaft portion 5a protruding from the wheel nut 19 is shown, and illustration of other portions of the wheel bolt 5 is omitted. Further, in FIGS. 4, 9, and 10, in addition to the wheel bolt 5, illustration of the hubs 3a to 3c and the wheels 7a to 7e is also omitted.

[0044] As shown in FIGS. 2 and 3, in each front wheel Wf, each first rear wheel Wr1, and each second rear wheel Wr2, a loosening prevention device 100 is disposed so as to cover the hub attachment portion of each wheel 7a, the hub attachment portion 15a of each outer wheel 7c, and the hub attachment portion 15a of each outer wheel 7e. These loosening prevention devices 100 all have the same configuration.

[0045] As shown in FIG. 4, the wheel nut 19 has six nut side surfaces 19d on the outer peripheral surface of the nut main body portion 19b. The nut side surface 19d is an example of the "side surface" in the present invention.

[0046] As shown in Figure 4, the anti-loosening device 100 consists of eight washers 10, four base plates 20, eight lock plates 30, one top ring 40, eight arrow fixing rings 50, eight arrow plates 60, and eight push nuts 70. Each washer 10, each base plate 20, each lock plate 30, each arrow fixing ring 50, each arrow plate 60, and each push nut 70 are all identical parts. The push nut 70 is an example of a "stopper member" in this invention.

[0047] As shown in Figure 4, the washer 10 is an annular metal ring and has a washer insertion hole 10a that penetrates around the washer axis, which coincides with the axis X.

[0048] As shown in Figure 4, the base plate 20 is made of a metal plate such as high-tensile steel with a thickness of about 3 mm, and both ends in the longitudinal direction are formed in an arc-shaped spectacle shape. Around the first base axis, which coincides with the axis X, a first base insertion hole 21 is provided at one end in the longitudinal direction of the base plate 20 for inserting the nut body portion 19b of the wheel nut 19. Around the second base axis, which coincides with the axis X of the shaft portion 5a that is inserted into the nut insertion hole 19c of the adjacent wheel nut 19, a second base insertion hole 22 is provided at the other end in the longitudinal direction of the base plate 20 for inserting the nut body portion 19b of the adjacent wheel nut 19. As a result, the base plate 20 is restricted from swinging with either of the adjacent wheel nuts 19 as the pivot point. Furthermore, two weight-reducing holes 23 are provided in the longitudinal center of the base plate 20. Furthermore, the material of the base plate 20 is not limited to metal; it may also be a resin such as fiber-reinforced resin or engineering plastic.

[0049] Furthermore, the inner circumferential surface of the first base insertion hole 21 has a first base uneven surface 21a formed thereon, in which n peaks and n valleys are arranged alternately and evenly around the axis of the first base. Similarly, the inner circumferential surface of the second base insertion hole 22 has a second base uneven surface 22a formed thereon, in which n peaks and n valleys are arranged alternately and evenly around the axis of the second base. In this embodiment, 60 peaks and 60 valleys are arranged alternately throughout the entire circumferential direction of the first base insertion hole 21 and the second base insertion hole 22.

[0050] As shown in Figure 4, the lock plate 30 is made of a metal plate such as high-tensile steel with a thickness of about 3 mm, and has a lock insertion hole 30a that penetrates through it around a lock axis that coincides with the axis X, and is formed in a substantially annular shape. The wheel nut 19 is inserted through the lock insertion hole 30a regardless of the rotation angle of the wheel bolt 5 with respect to the shaft portion 5a. The lock insertion hole 30a also allows the wheel nut 19 to be inserted while defining the loosening angle, which will be described later, as an allowable angle. Note that the material of the lock plate 30 is not limited to metal, but may also be a resin such as fiber-reinforced resin or engineering plastic.

[0051] A locking groove 30b is formed on the outer circumferential surface of the locking plate 30. The locking groove 30b is formed with n peaks and n valleys arranged alternately and evenly around the locking axis. In this embodiment, 60 peaks and 60 valleys are formed alternately along the entire circumferential surface of the locking plate 30.

[0052] The lock insertion hole 30a in the lock plate 30 has six inner lock hole surfaces 30c, each corresponding to one of the six nut sides 19d. Each inner lock hole surface 30c has a central projection 30d, a clockwise contact portion 30e, a counterclockwise contact portion 30f, a first inclined surface 30h, and a second inclined surface 30i. Each central projection 30d is the surface (flat or curved) located at the shortest distance from the lock axis on the inner lock hole surface 30c, with the lock axis as its center and the radius being the distance from the nut axis of the wheel nut 19 to the nut side 19d plus an extremely small gap of about 0.1 to 0.3 mm. The first inclined surface 30h is a surface (flat or curved) that is inclined radially outward from the central projection 30d toward one side in the circumferential direction, and the second inclined surface 30i is a surface (flat or curved) that is inclined radially outward from the central projection 30d toward the other side in the circumferential direction. Here, we assume a virtual tangent TL on the central projection 30d of the virtual inscribed circle IC. The clockwise contact portion 30e is formed when the nut side surface 19d of the wheel nut 19 is parallel to the virtual tangent TL, and the wheel nut 19 rotates clockwise (in the other direction of circumferential rotation) relative to the lock plate 30 by a first rotation angle θ. 1 The convex portion that makes contact when rotated is located near one end of the first inclined surface 30h in the circumferential direction and protrudes from the first inclined surface 30h toward the nut side surface 19d. The counterclockwise contact portion 30f is located at a position where the nut side surface 19d of the wheel nut 19 is parallel to the virtual tangent line TL, and the wheel nut 19 rotates counterclockwise (one side in the circumferential direction) relative to the lock plate 30 at a second rotation angle θ 2 The convex portion is the part that contacts the wheel nut 19 when it rotates. The convex portion is located near the other end of the second inclined surface 30i in the circumferential direction and protrudes from the second inclined surface 30i toward the nut side surface 19d. As a result, the rotatable angle (allowable angle A) of the wheel nut 19 relative to the lock plate 30 is θ 1 +θ 2 Therefore, A = θ 1 +θ 2 The above is true. Note that the clockwise contact portion 30e and the counterclockwise contact portion 30f are shown only in Figures 6 to 8, and are omitted from the other figures.

[0053] Furthermore, the lock insertion hole 30a has six flat connecting portions 30g that connect adjacent inner surfaces 30c of the lock holes in the circumferential direction, each consisting of a flat surface. The flat connecting portions 30g are an example of a "connecting portion" in the present invention. The flat connecting portions 30g have an extremely small gap of about 0.1 to 0.3 mm with respect to the nut corner portion 19e of the wheel nut 19.

[0054] As shown in Figure 4, the top ring 40 is made of a hard synthetic resin and is formed in an annular shape of a predetermined width with a central hole 40a. The top ring 40 has eight top insertion holes 40b that are arranged at equal intervals in the circumferential direction of the top ring 40 and penetrate around the top ring axis which coincides with the axis X, and through which the nut body portion 19b of each wheel nut 19 is inserted. The top ring 40 has a wall portion 40d that extends from the outer circumferential surface of the top ring 40 along the axis X in the direction of the wheel nut 19. The top ring 40 can cover all of the base plates 20 and lock plates 30 attached to each wheel nut 19, and also prevents the risk of injury caused by exposed metal end faces.

[0055] As shown in Figure 11, the arrow fixing ring 50 is made of a thin sheet of synthetic resin and has a fixing ring insertion hole 50a that penetrates around the fixing ring axis which coincides with the axis X, and is formed in a substantially annular shape.

[0056] The inner circumferential surface of the fixing ring insertion hole 50a is hexagonal in shape, corresponding to the outer circumferential surface shape of the nut body portion 19b of the wheel nut 19. As a result, the arrow fixing ring 50 is made unable to rotate relative to the wheel nut 19 by inserting the nut body portion 19b of the wheel nut 19 through the fixing ring insertion hole 50a.

[0057] Furthermore, a fixing ring uneven surface 50b is formed on the outer circumferential surface of the arrow fixing ring 50. The fixing ring uneven surface 50b is formed with m peaks and m valleys arranged alternately around the axis of the fixing ring. In this embodiment, 360 peaks and 360 valleys are formed alternately around the entire circumference of the arrow fixing ring 50.

[0058] As shown in Figure 11, the arrow plate 60 is made of a thin sheet of synthetic resin, is inserted around the arrow axis which coincides with the axis X, and is formed in a substantially annular shape with an arrow plate insertion hole 60a.

[0059] Furthermore, the arrow plate 60 is thicker than the arrow fixing ring 50, having a thickness approximately twice that of the arrow fixing ring 50. On the back surface 60b of the arrow plate 60, an annular recess 60c capable of accommodating the arrow fixing ring 50 is recessed around the arrow axis. An arrow plate uneven surface 60d is formed on the inner surface of the annular recess 60c. The arrow plate uneven surface 60d is formed with m peaks and m valleys arranged alternately around the arrow axis. In this embodiment, the arrow plate uneven surface 60d has 360 peaks and 360 valleys arranged alternately around the entire circumferential direction of the annular recess 60c.

[0060] Furthermore, a directional indicator portion 60e is formed on the outer circumferential surface of the arrow plate 60, projecting radially outward in a triangular shape. The directional indicator portion 60e defines the direction of the arrow on the arrow plate 60.

[0061] As shown in Figure 11, the push nut 70 is made of a thin spring steel sheet and is formed in a substantially annular shape with a push insertion hole 70a that penetrates around a push axis that coincides with the axis X.

[0062] The push insertion hole 70a in the push nut 70 is formed in a shape and size that allows the nut body portion 19b of the wheel nut 19 to be inserted through it. Specifically, the push insertion hole 70a is a substantially hexagonal shape corresponding to the outer circumferential surface shape of the nut body portion 19b. Each side of the hexagon in the push insertion hole 70a has a recess 70c formed in the radially outward direction of the push axis. Furthermore, each recess 70c has a substantially rectangular shape extending radially inward from the bottom surface of the recess 70c towards the push axis, and a claw portion 70b is formed that extends radially inward from each side of the hexagon in the push insertion hole 70a and is elastically deformable.

[0063] As shown in Fig. 4, these parts are inserted into the nut main body portion 19b of the wheel nut 19 in the order of washer 10, base plate 20, lock plate 30, top ring 40, arrow fixing ring 50, arrow plate 60 and push nut 70, and then are pushed toward the nut base portion 19a by the installation adapter IA from above the push nut 70, thereby being mounted on the wheel nut 19.

[0064] As shown in Fig. 10, the first base concavo-convex portion 21a of the first base insertion hole 21 and the lock concavo-convex portion 30b of the lock plate 30 are in concavo-convex fitting. That is, each peak portion of the first base concavo-convex portion 21a and each valley portion of the lock concavo-convex portion 30b are respectively fitted, and each valley portion of the first base concavo-convex portion 21a and each peak portion of the lock concavo-convex portion 30b are respectively fitted. And in a state where the first base concavo-convex portion 21a and the lock concavo-convex portion 30b are in concavo-convex fitting, an extremely minute gap of about 0.1 to 0.3 mm is provided between each peak portion of the first base concavo-convex portion 21a and each valley portion of the lock concavo-convex portion 30b, and between each valley portion of the first base concavo-convex portion 21a and each peak portion of the lock concavo-convex portion 30b.

[0065] In a state where this anti-loosening device 100 is mounted on the wheel nut 19 and the nut main body portion 19b of the wheel nut 19 is inserted into the lock insertion hole 30a, if the wheel nut 19 is mounted at an angular position (parallel) where the direction of the nut side surface 19d coincides with the direction of the virtual tangent line TL shown in Figs. 5 and 6, the rotational angle R in the clockwise direction of the wheel nut 19 with respect to the lock plate 30 is the first rotational angle θ 1 coincides with (θ 1 =R), and the rotational angle L in the counterclockwise direction of the wheel nut 19 with respect to the lock plate 30 is the second rotational angle θ 2 coincides with (θ 2 =L). Therefore, when the wheel nut 19 inserted into the lock insertion hole 30a rotates in the loosening direction, due to the contact between the nut side surface 19d of the wheel nut 19 rotating in the loosening direction and the counterclockwise contact portion 30f, the rotation in the loosening direction is restricted to a loosening angle (rotational angle L in the counterclockwise direction) not exceeding the allowable angle A shown by the following formula (1). R + L = A …(1)

[0066] In other words, when the nut body portion 19b of the wheel nut 19 is inserted through the first base insertion hole 21 and the lock insertion hole 30a, and the first base recessed portion 21a and the lock recessed portion 30b are engaged in recessed-recessed fitting, if the wheel nut 19 is mounted on the lock plate 30 at a position where the nut side surface 19d and the right-hand contact portion 30e are in contact, then rotation in the right-hand direction is impossible. Therefore, the rotation angle R in the right-hand direction is 0 degrees, and as shown in equation (1) above, L = A, and the rotation angle L (loosening angle) in the loosening direction (counter-clockwise direction) is the same as the allowable angle A.

[0067] Similarly, when the wheel nut 19 is mounted on the lock plate 30 in a state of interlocking grooves and protrusions, if the nut side surface 19d and the counterclockwise contact portion 30f are in contact, rotation in the counterclockwise direction is not possible. As shown in equation (1) above, the rotation angle L in the counterclockwise direction is 0 (degrees), so R = A, and since the allowable angle A is the rotation angle R in the tightening direction (clockwise direction), rotation in the loosening direction (counterclockwise direction) will not occur.

[0068] In this embodiment, the magnitude of the allowable angle A is set as follows. That is, when the number of peaks in the locking groove portion 30b is n, the allowable angle A is given by A in equation (2) below, and the value of the allowable angle A is set such that each wheel nut 19 is inserted into the locking plate 30 regardless of the rotation angle with respect to the shaft portion 5a, and the base plate 20 and the locking plate 30 are mounted so that they cannot rotate relative to each other. 360 / n ≤ A …(2)

[0069] In equation (2) above, the value of 360 / n is the angle of one peak / trough in the lock protrusions 30b. Therefore, from equation (2) above, the wheel nut 19 can rotate by an allowable angle A, which is an angle of one peak / trough or more, within the lock insertion hole 30a. In other words, when the first base protrusions 21a and the lock protrusions 30b are not engaged, the lock plate 30, through which the nut body portion 19b of the wheel nut 19 is inserted into the lock insertion hole 30a, can be rotated by an angle of one peak / trough or more.

[0070] Therefore, as shown in Figure 9, the lock plate 30, through which the nut body portion 19b of the wheel nut 19 is inserted, can be rotated clockwise or counterclockwise by an angle smaller than the angle of one peak or valley, relative to the first base insertion hole 21 through which the nut body portion 19b of the wheel nut 19 is inserted. This allows the first base recessed portion 21a and the lock recessed portion 30b to be interlocked. Alternatively, the base plate 20 and the two lock plates 30 may be assembled first and then inserted through the nut body portion 19b.

[0071] Furthermore, by restricting the wheel nut 19 to rotate only by a loosening angle less than or equal to the allowable angle A in the loosening direction, it is possible to suppress the decrease in frictional force between the hubs 3a to 3c and the wheels 7a to 7e due to a decrease in the axial force of the wheel bolts 5 to which the wheel nut 19 is fastened.

[0072] In equation (2) above, as the value of n decreases, that is, as the number of peaks in the locking groove portion 30b decreases, the allowable angle A increases, and the decrease in axial force of the wheel bolt 5 caused by the rotational loosening of the wheel nut 19 also increases. In addition, since the volume of the lock plate 30 decreases, the strength of the lock plate 30 also decreases.

[0073] On the other hand, in equation (2) above, if the value of n becomes too large and the number of peaks in the locking recessed portion 30b becomes excessive, the shape of each recess in the locking recessed portion 30b becomes smaller, making it difficult to form the locking recessed portion 30b, or making it difficult to secure the strength to prevent the wheel nut 19 from rotating loosened by the recessed fitting between the first base recessed portion 21a and the locking recessed portion 30b.

[0074] Therefore, it is desirable that the value of n be set between 30 and 120, and that the allowable angle A satisfy equation (2) above and be as small as possible.

[0075] The above explanation regarding the wheel nut 19, the first base insertion hole 21, and the lock plate 30 is the same for the adjacent wheel nut 19, the second base insertion hole 22, and the lock plate 30, so the explanation is omitted.

[0076] The recessed and concave portions 50b of the arrow fixing ring 50 and the recessed and concave portions 60d of the arrow plate 60 engage in a recessed and concave fitting. That is, each peak of the recessed and concave portion 50b of the fixing ring engages with each valley of the recessed and concave portion 60d of the arrow plate, and each valley of the recessed and concave portion 50b of the fixing ring engages with each peak of the recessed and concave portion 60d of the arrow plate.

[0077] The arrow plate insertion hole 60a in the arrow plate 60 is formed in a circular shape with an outer diameter slightly larger than the circumscribed circle of the nut body portion 19b of the wheel nut 19. As a result, the arrow plate 60 is rotatable relative to the wheel nut 19 by inserting the nut body portion 19b of the wheel nut 19 through the arrow plate insertion hole 60a.

[0078] As shown in Figure 4, when attaching the arrow fixing ring 50 and the arrow plate 60 to the wheel nut 19, first the nut body portion 19b of the wheel nut 19 is inserted through the fixing ring insertion hole 50a to hold the arrow fixing ring 50 in a position where it cannot rotate relative to the wheel nut 19. Then, the nut body portion 19b of the wheel nut 19 is inserted through the arrow plate insertion hole 60a, and the protrusions and recesses 50b of the fixing ring and the protrusions and recesses 60d of the arrow plate are fitted together while adjusting the direction indicator portion 60e to a predetermined orientation. This allows the arrow plate 60 to be attached to the wheel nut 19 while adjusting the orientation of the direction indicator portion 60e in 1-degree increments. Alternatively, the arrow fixing ring 50 and the arrow plate 60 may be assembled first and then inserted through the nut body portion 19b.

[0079] As shown in Figure 4, in this embodiment, the arrow plate 60 is attached to the wheel nut 19 so that the two direction indicators 60e face each other. Therefore, by visually observing the misalignment of the two direction indicators 60e, it is possible to confirm the rotational loosening of the wheel nut 19.

[0080] The six claw portions 70b of the push nut 70 contact each nut side 19d of the wheel nut 19, which is inserted through the push insertion hole 70a, while elastically deforming. As a result, the push nut 70 is firmly held by the nut body portion 19b of the wheel nut 19. And, because the push nut 70 is held by the wheel nut 19, the washer 10, base plate 20, lock plate 30, top ring 40, arrow fixing ring 50 and arrow plate 60 are prevented from falling off the wheel nut 19.

[0081] In the anti-loosening device 100 of Embodiment 1, as shown in Figure 4, etc., the base plate 20 is mounted on adjacent wheel nuts 19 so that they cannot move relative to each other. That is, the base plate 20 is restricted from swinging with the wheel nuts 19 as the pivot point. Furthermore, the lock plates 30 held in the first base insertion hole 21 and the second base insertion hole 22 of the base plate 20 are reliably prevented from rotating relative to the base plate 20 by the interlocking of the first base protrusions 21a and the second base protrusions 22a with the lock protrusions 30b. Even if rotational loosening occurs in the wheel nut 19 inserted through the lock insertion hole 30a of the lock plate 30, when it rotates counterclockwise by an angle (loosening angle) less than or equal to the allowable angle A, each nut side surface 19d of the wheel nut 19 comes into contact with the counterclockwise contact portion 31f, thereby preventing rotational loosening exceeding the allowable angle A from occurring in the wheel nut 19. In this way, the decrease in the axial force of the wheel bolt 5 caused by the rotational loosening of the wheel nut 19 can be reliably prevented.

[0082] Furthermore, this anti-loosening device 100 can suppress a decrease in the axial force of the wheel bolts 5, and consequently, the frictional force between the hubs 3a-3c and the wheels 7a-7e. As a result, it is possible to reliably prevent the wheels (front wheel Wf, first rear wheel Wr1, second rear wheel Wr2) from falling off due to the breakage of the wheel bolts 5 or the detachment of the wheel nuts 19.

[0083] Furthermore, since this anti-loosening device 100 can be used as is on existing large trucks 1 without requiring the replacement of the wheel bolts 5, expensive modification costs are unnecessary.

[0084] Therefore, this anti-loosening device 100 does not require expensive modification costs even when used on existing large trucks 1, and it can suppress the decrease in axial force of the wheel bolts 5 due to the rotational loosening of the wheel nuts 19.

[0085] Furthermore, in this anti-loosening device 100, the rotational force from the wheel nut 19 can be received by the entire annular lock plate 30. In addition, the load from the wheel nut 19 can be withstood by the tensile force between the lock plate 30 and the base plate 20. As a result, deformation of the lock plate 30 and the base plate 20 can also be suppressed.

[0086] In particular, with this anti-loosening device 100, when the wheel nut 19 rotates and loosens, the six nut sides 19d of the wheel nut 19 and the six counter-clockwise contact portions 31f come into contact with each other, so that the load is transmitted evenly from each nut side 19d to each counter-clockwise contact portion 31f. This is advantageous in ensuring the strength of the lock plate 30.

[0087] Furthermore, in this anti-loosening device 100, adjacent inner surfaces 30c of lock holes 30a are connected via a flat connecting portion 30g. This is advantageous for ensuring the radial width of the lock plate 30 and thus ensuring strength at the boundary between the inner surfaces 30c of the lock holes.

[0088] Furthermore, in this anti-loosening device 100, numerous peaks and valleys in the first base uneven portion 21a are formed on the inner circumferential surface of the first base insertion hole 21, and numerous peaks and valleys in the second base uneven portion 22a are formed on the inner circumferential surface of the second base insertion hole 22. Therefore, the first base uneven portion 21a and the second base uneven portion 22a can be formed without increasing the thickness of the base plate 20. Also, since numerous peaks and valleys in the lock uneven portion 30b are formed on the outer circumferential surface of the lock plate 30, the lock uneven portion 30b can be formed without increasing the thickness of the lock plate 30. For this reason, it is advantageous for reducing the weight of the base plate 20 and the lock plate 30.

[0089] Furthermore, in this anti-loosening device 100, each base plate 20 and each lock plate 30 is covered by a top ring 40. The top ring 40 is then prevented from falling off the wheel nut 19 by each push nut 70 fixed to each wheel nut 19. As a result, the base plates 20 and lock plates 30 can be reliably prevented from falling off the wheel nuts 19. In addition, even if a flying object hits a push nut 70 during driving and causes it to fall off, or if a push nut 70 hits a fixed object on the road and causes it to fall off, the remaining push nuts 70 can prevent the top ring 40 from falling off the wheel nut 19, and consequently, all base plates 20 and all lock plates 30 can be reliably prevented from falling off the wheel nuts 19.

[0090] Furthermore, in this anti-loosening device 100, the direction of the arrow on the arrow plate 60 can be adjusted in 1-degree increments. Therefore, for example, as shown in Figure 4, the direction of the arrows on two adjacent arrow plates 60 can be precisely aligned. As a result, the occurrence of rotational loosening of the wheel nut 19 can be visually detected more reliably.

[0091] (Example 2) As shown in Figure 12, the anti-loosening device 101 in Example 2 uses a C-ring 80 instead of the push nut 70 in the anti-loosening device 100 of Example 1. The C-ring 80 is an example of a "stopper member" in the present invention.

[0092] Furthermore, in the anti-loosening device 101 of Embodiment 2, a wheel nut 190 is used instead of the wheel nut 19 of Embodiment 1. Six engagement grooves 190d are formed in the nut body portion 190b of each wheel nut 190. Each engagement groove 190d extends along the circumferential direction of the nut body portion 190b at the six nut corner portions 190e of the nut body portion 190b. Each engagement groove 190d is sized to allow the C-ring 80 to be fitted.

[0093] The C-ring 80 is made of a thin sheet of spring steel and is formed in a C-shape. The C-ring 80 is elastically deformable in the direction of expansion and contraction. The C-ring 80 is sized to be held by the nut body portion 190b of the wheel nut 190 while undergoing elastic deformation in the direction of expansion, and to be firmly held by the nut body portion 190b by an elastic restorative force in the direction of contraction.

[0094] Then, the C-ring 80 fits into and engages with each engagement groove 190d of the wheel nut 190, thereby fixing the C-ring 80 to the nut body portion 190b of the wheel nut 190.

[0095] The other configurations and effects of this anti-loosening device 101 are the same as those of the anti-loosening device 100 in Example 1.

[0096] (Example 3) As shown in Figure 13, the anti-loosening device 102 in Example 3 eliminates the arrow fixing ring 50 in the anti-loosening device 100 of Example 1 and is provided with double-sided tape 90.

[0097] The double-sided tape 90 is annular in shape and has a tape insertion hole 91 that penetrates around the tape axis, which coincides with the axis X. The tape insertion hole 91 is formed in a circular shape that is large enough for the nut body portion 19b of the wheel nut 19 to be inserted through.

[0098] Although not shown in the diagram, adhesive layers are formed on both the front and back surfaces of the double-sided tape 90, allowing it to adhere to the arrow plate 63 and the push nut 70. The specific material and structure of the double-sided tape 90 are not particularly limited, but it is preferable that it has strong adhesive strength suitable for industrial products.

[0099] The arrow plate 63 in this anti-loosening device 102 is made of a thin sheet of synthetic resin, is formed in a substantially annular shape, and is attached to the wheel nut 19.

[0100] The arrow plate 63 is thinner than the arrow plate 60 in the anti-loosening device 100 of Embodiment 1, and has a thickness similar to that of the arrow fixing ring 50 in the anti-loosening device 100 of Embodiment 1. The arrow plate 63 also has an arrow plate insertion hole 63a that penetrates around the arrow axis, which coincides with the axis X. The arrow plate insertion hole 63a is formed in a circular shape with an outer diameter slightly larger than the circumscribed circle of the nut body portion 19b of the wheel nut 19. As a result, the arrow plate 63 is rotatable relative to the wheel nut 19 by inserting the nut body portion 19b of the wheel nut 19 into the arrow plate insertion hole 63a.

[0101] Furthermore, a directional indicator portion 63e is formed on the outer circumferential surface of the arrow plate 63, projecting radially outward in a triangular shape. The directional indicator portion 63e defines the direction of the arrow on the arrow plate 63.

[0102] For example, the arrow plate 63, double-sided tape 90, and push nut 70 can be attached to the wheel nut 19 as follows. First, the nut body portion 19b of the wheel nut 19 is inserted through the arrow plate insertion hole 63a, and the arrow plate 63 is attached to the wheel nut 19. Then, the double-sided tape 90 is adhered to the push nut 70. After that, while orienting the double-sided tape 90 toward the arrow plate 63, the nut body portion 19b of the wheel nut 19 is inserted through the push insertion hole 70a and the tape insertion hole 91. At this time, the direction indicator portion 63e of the arrow plate 63 is adjusted to a predetermined direction, and while maintaining that state, the push nut 70 is pushed toward the nut base portion 19a of the wheel nut 19. This causes each claw portion 70b to be elastically supported by the nut body portion 19b, and the double-sided tape 90 is adhered to the arrow plate 63. In this way, the attachment of the arrow plate 63, double-sided tape 90, and push nut 70 to the wheel nut 19 is completed.

[0103] The other configurations and effects of this anti-loosening device 102 are the same as those of the anti-loosening device 100 in Example 1.

[0104] (Example 4) As shown in Figures 14 to 19, the anti-loosening device 103 in Example 4 has modified shapes of the top ring 40, lock plate 30, and arrow plate 60 compared to the anti-loosening device 100 in Example 1.

[0105] As shown in Figure 14, the top ring 43 in this anti-loosening device 103 is formed in a substantially annular shape with a central hole 43a and has a top insertion hole 43c that penetrates around the top ring axis, which coincides with the axis X. On the outer circumferential surface of the top ring 43, a concave curved surface portion 43b is formed at positions between each top insertion hole 43c, recessed inward in the radial direction of the central hole 43a and extending along the axis X toward the wheel nut 19. The top ring 43 can also cover all of the base plates 20 and lock plates 33 attached to each wheel nut 19, and prevents any risk of injury due to exposed metal end faces.

[0106] The lock plate 33 in this anti-loosening device 103 is attached to the wheel nut 19. The basic configuration of the lock plate 33 is the same as that of the lock plate 30 in the anti-loosening device 100 of Embodiment 1.

[0107] In other words, the lock plate 33 has a lock insertion hole 33a that penetrates around a lock axis that coincides with the axis X, a lock protrusion 33b, an inner surface of the lock hole 33c, a central projection 33d, a right-handed contact portion 33e, a left-handed contact portion 33f, a first inclined surface 33h, a second inclined surface 33i, and a flat connecting portion 33g. These have the same configuration as the lock insertion hole 30a, lock protrusion 30b, inner surface of the lock hole 30c, central projection 30d, right-handed contact portion 30e, left-handed contact portion 30f, first inclined surface 30h, second inclined surface 30i, and flat connecting portion 30g in the lock plate 30 of Embodiment 1. Note that the right-handed contact portion 33e and the left-handed contact portion 33f are omitted from the illustration in Figures 14 to 18.

[0108] Furthermore, in the lock plate 33, when the anti-loosening device 103 is installed, the surface facing the hubs 3a to 3c is designated as the back surface 33j, and the surface of the lock plate 33 facing the opposite side of the back surface 33j is designated as the front surface 33k.

[0109] As shown in Figure 15 and other figures, the lock plate 33 has a plurality of restricting portions 35, and in this embodiment, three restricting portions 35 are provided on the outer peripheral edge of the lock plate 33. Each restricting portion 35 is evenly arranged in the circumferential direction of the lock plate 33. Each restricting portion 35 is integrally formed on the back surface 33j of the lock plate 33. Each restricting portion 35 has a similar shape.

[0110] With the anti-loosening device 103 attached to the wheel nut 19, the restricting portion 35 protrudes toward the hub 3a to 3c side in the thickness direction of the lock plate 33 and extends radially outward with respect to the shaft portion 5a of the wheel bolt 5.

[0111] The restricting portion 35 is provided in the area where two peaks have been removed from the locking recessed portion 33b. The restricting portion 35 has a circular contact surface 35a facing the surface 33k side of the locking plate 33. The circular contact surface 35a and the back surface 33j of the locking plate 33 are located on the same plane. As shown in Figure 16, the diameter of the virtual circumscribed circle C1 of each circular contact surface 35a is set to be larger than the diameter of the virtual circumscribed circle C2 of the locking recessed portion 33b.

[0112] The restricting portion 35 has a semi-conical side surface 35b that protrudes from the back surface 33j of the lock plate 33. The semi-conical side surface 35b tapers towards the protruding tip of the restricting portion 35 from the back surface 33j of the lock plate 33. The diameter of the maximum diameter portion of the semi-conical side surface 35b, which is the boundary with the back surface 33j, is set to be larger than the diameter of the circular contact surface 35a.

[0113] As shown in Figures 17 and 18, when the anti-loosening device 103 is installed, the central projection 33d of the lock plate 33 abuts against the nut base 19a of the wheel nut 19, and the back surface 20a of the base plate 20, which faces the hub 3a to 3c side when the anti-loosening device 103 is installed, abuts against the circular contact surface 35a of each restricting portion 35. More specifically, the circular contact surface 35a of each restricting portion 35 abuts against the back surface 20a of the peaks of the first base recessed portion 21a.

[0114] Thus, when the anti-loosening device 103 is installed, the circular contact surfaces 35a of each restricting portion 35 come into contact with the back surface 20a of the base plate 20, and the central protrusion 33d of the lock plate 33 comes into contact with the nut base 19a of the wheel nut 19, thereby restricting the base plate 20 from moving toward the hub 3a-3c side. As a result, the amount of engagement of the interlocking grooves due to misalignment in the axial X direction between the base plate 20 and the lock plate 33 is not reduced, and a good engagement state between the base plate 20 and the lock plate 33 can be reliably maintained. As a result, rotational prevention strength due to the interlocking grooves can be ensured.

[0115] Furthermore, this anti-loosening device 103 eliminates the washer 10 found in the anti-loosening device 100 of Embodiment 1. This allows for cost reduction and weight reduction by eliminating the washer 10. Also, compared to the anti-loosening device 100 of Embodiment 1, the push nut 70 moves towards the hub side by the thickness of the washer 10, increasing the distance from the claw portion 70b of the push nut 70 to the end face on the nut body portion 19b side of the wheel nut 19, making it more difficult for the push nut 70 to come off.

[0116] Furthermore, the arrow plate 65 in this anti-loosening device 103 is made of a thin sheet of synthetic resin, is formed in a substantially annular shape, and is attached to the wheel nut 19.

[0117] The arrow plate 65 is thinner than the arrow plate 60 in the anti-loosening device 100 of Embodiment 1, and has a thickness equivalent to that of the arrow fixing ring 50. As shown in Figure 19, the arrow plate 65 has an arrow plate insertion hole 65a that penetrates around the arrow axis, which coincides with the axis X. The arrow plate insertion hole 65a is sized to allow the arrow fixing ring 50 to pass through. An arrow plate uneven surface 65b is formed on the inner circumferential surface of the arrow plate insertion hole 65a. The arrow plate uneven surface 65b is formed with m peaks and m valleys arranged alternately around the arrow axis, which coincides with the axis X.

[0118] In this embodiment, the arrow plate's uneven surface 65b has 360 peaks and 360 valleys arranged alternately around the entire circumference of the arrow plate insertion hole 65a. The fixing ring's uneven surface 50b of the arrow fixing ring 50 and the arrow plate's uneven surface 65b of the arrow plate 65 engage in an uneven fit.

[0119] Furthermore, a directional indicator portion 65c is formed on the outer circumferential surface of the arrow plate 65, projecting in a triangular shape radially outward from the arrow plate 65. The directional indicator portion 65c defines the direction of the arrow on the arrow plate 65.

[0120] The other configurations and effects of this anti-loosening device 103 are the same as those of the anti-loosening device 100 in Example 1.

[0121] Although the present invention has been described above in reference to Examples 1 to 4, it goes without saying that the present invention is not limited to Examples 1 to 4, and can be applied with appropriate modifications without departing from its spirit.

[0122] Examples 1 to 4 describe a wheel with eight wheel nuts 19 screwed onto the wheel bolts 5, and the required number of each component, the number of insertion holes, etc., are described accordingly. However, the present invention is not limited to this. For example, it is also possible to use a wheel with six or ten wheel nuts 19 screwed onto the wheel bolts 5, and to increase or decrease the required number of each component, the number of insertion holes, etc., accordingly.

[0123] In Examples 1 to 4, the base plate 20 has a first base insertion hole 21 and a second base insertion hole 22 and is attached to two adjacent wheel nuts 19, 190, but the present invention is not limited thereto. For example, the base plate may have four base insertion holes and be attached to four wheel nuts 19, 190 that are continuous in the circumferential direction, or it may have three base insertion holes and be attached to three wheel nuts 19, 190 that are continuous in the circumferential direction.

[0124] In Examples 1 to 4, the right-hand contact portions 30e, 33e and the left-hand contact portions 30f, 33f are convex portions that contact the rotated wheel nuts 19, 190, but the present invention is not limited thereto. For example, the convex portions can be eliminated, and from a position where the nut side surface 19d of the wheel nuts 19, 190 is parallel to the virtual tangent line TL, the wheel nuts 19, 190 rotate clockwise (in the other direction in the circumferential direction) relative to the lock plates 30, 33 at a first rotation angle θ 1 The surfaces that come into contact when rotated (first inclined surfaces 30h, 33h) are made to be clockwise contact portions 30e, 33e, or the wheel nuts 19, 190 rotate counterclockwise (one side in the circumferential direction) relative to the lock plates 30, 33 at a second rotation angle θ 2 The surfaces that come into contact when rotated (second inclined surfaces 30i, 33i) may be designated as counterclockwise contact portions 30f, 33f.

[0125] In Examples 1 to 4, the connecting portion is a flat connecting portion made of a flat surface, but the present invention is not limited thereto. For example, it may be a curved connecting portion made of a concave curved surface that is recessed radially outward when viewed from the direction of the lock axis of the lock insertion hole.

[0126] In Examples 1 to 4, the lock insertion hole 30a has six lock hole inner surfaces 30c corresponding to six nut sides 19d, but the present invention is not limited thereto. For example, the lock insertion hole 30a may have two or three lock hole inner surfaces 30c, each having a central projection 30d, a clockwise contact portion 30e, and a counterclockwise contact portion 30f. When the lock insertion hole 30a has two or three lock hole inner surfaces 30c, it is preferable that each lock hole inner surface 30c is arranged at equal intervals in the circumferential direction of the lock insertion hole 30a.

[0127] In Examples 1 to 4, a push nut 70 or C-ring 80 attached to each of the wheel nuts 19 and 190 is used as the stopper member, but the present invention is not limited thereto. For example, in Examples 1 to 4, the stopper member may be attached to two wheel nuts 19 and 190, or to four wheel nuts 19 and 190.

[0128] In Examples 1 to 4, the arrow plates 60 and 65 and the top rings 40 and 43 may be omitted, and in Examples 1 to 3, the washer 10 may be omitted.

[0129] In Embodiment 4, the shape and number of the restricting portion 35 are not particularly limited, and the shape and number of the restricting portion 35 can be appropriately set so as to restrict the movement of the base plate toward the hub side.

[0130] In Examples 1 to 4, rotation in the counterclockwise direction is considered the loosening direction (right-hand thread), but this is not the only option. It can also be used in wheels where rotation in the clockwise direction is considered the loosening direction (left-hand thread).

[0131] This invention can be used in a wheel-off prevention device for large trucks.

[0132] 100, 101, 102, 103... Wheel nut anti-loosening device 1... Large truck (large vehicle) 3a-3c... Hub 5... Wheel bolt 5a... Axle part 7a-7e... Wheel 9a, 9b... Tire Wf, Wr1, Wr2... Wheel (Wf... Front wheel, Wr1... First rear wheel, Wr2... Second rear wheel) 13b... Wheel bolt hole 19, 190... Wheel nut 19d... Nut side (side) 20... Base plate 21... First base insertion hole (base insertion hole) 21a... First base uneven part (base uneven part) 22... Second base insertion hole (base insertion hole) 22a... Second base uneven part (base uneven part) 30, 33... Lock plate 30a, 33a... Lock insertion hole 30b, 33b... Lock uneven part 30c, 33c...Inner surface of lock hole 30e, 33e...Right-hand contact part 30f, 33f...Left-hand contact part 30g, 33g...Flat connecting part (connecting part) 40, 43...Top ring 40b, 43c...Top insertion hole 70...Push nut (stopper member) 35...Restricting part 50...Arrow fixing ring 50a...Fixing ring insertion hole 50b...Fixing ring uneven part 60, 65...Arrow plate 60a, 65a...Arrow plate insertion hole 60d, 65b...Arrow plate uneven part 80...C-ring (stopper member)

Claims

1. A wheel nut loosening prevention device that is attached to multiple wheel nuts of a large vehicle to suppress the rotational loosening of at least one of the wheel nuts, wherein the large vehicle comprises a hub to which multiple wheel bolts are fixed and the shaft portion of each wheel bolt protrudes, and a wheel to which a tire is assembled to constitute a wheel, wherein the same number of wheel bolt holes as the wheel bolts are provided through the wheel, and the shaft portion of each wheel bolt is inserted through each wheel bolt hole and screwed in by each wheel nut, thereby fixing to the hub, and further comprising a base plate attached to at least two adjacent wheel nuts, which restricts the oscillation with any of the wheel nuts as the pivot point, and a lock plate through which each wheel nut is inserted regardless of the rotation angle with respect to the shaft portion and which is mounted so as not to rotate relative to the base plate, and which contacts the side surface of the wheel nut that rotates in the loosening direction to restrict the rotation in the loosening direction to a loosening angle below the allowable angle.

2. The wheel nut anti-loosening device according to claim 1, wherein the shaft portion is formed around an axis, the base plate has a base insertion hole through which each wheel nut is inserted, centered on a base axis that coincides with each axis, and a base recess formed on the inner circumferential surface of each base insertion hole and uniformly formed around the base axis, and each lock plate has a lock insertion hole through which each wheel nut is inserted, centered on a lock axis that coincides with each axis, while defining the loosening angle to the allowable angle, and a lock recess formed on the outer circumferential surface that fits with the base recess for mounting to the base plate so as not to rotate relative to it.

3. In the base uneven portion, n peaks and n valleys are arranged alternately around the base axis; In the lock uneven portion, n peaks and n valleys are arranged alternately around the lock axis; The lock insertion hole has a right-hand contact portion and a left-hand contact portion formed therein, which contact the side surface of the wheel nut when the wheel nut rotates clockwise and counterclockwise relative to the lock plate; the rotation angle of the wheel nut in the clockwise direction relative to the lock plate is R; the rotation angle of the wheel nut in the counterclockwise direction relative to the lock plate is L; the allowable angle is the sum of the rotation angle R and the rotation angle L, and is represented by the following equations (1) and (2) for the wheel nut anti-loosening device according to claim 2. R + L = A …(1) 360 / n ≤ A …(2) 4. The wheel nut anti-loosening device according to claim 3, wherein the lock plate is annular in shape, the lock insertion hole has an inner surface of the lock hole corresponding to each of the sides, each inner surface of the lock hole has a right-hand contact portion and a left-hand contact portion, and adjacent inner surfaces of the lock holes in the circumferential direction are connected by a connecting portion.

5. A wheel nut loosening prevention device according to any one of claims 1 to 4, further comprising a stopper member for holding the base plate and the lock plate.

6. A wheel nut loosening prevention device according to any one of claims 1 to 4, comprising: an annular top ring having a plurality of top insertion holes through which all of the plurality of wheel nuts are each inserted, covering all of the base plates and all of the lock plates; and a stopper member that holds the top ring.

7. The wheel nut anti-loosening device according to any one of claims 1 to 4, wherein each lock plate protrudes toward the hub side in the thickness direction of the lock plate, then extends radially outward relative to the shaft portion, abuts against the base plate, and has a restricting portion that restricts the movement of the base plate toward the hub side.

8. A wheel nut anti-loosening device according to any one of claims 1 to 4, comprising: an arrow fixing ring that is provided through a fixing ring shaft that coincides with each of the aforementioned axes and has a fixing ring insertion hole through which the wheel nut is inserted coaxially and is mounted on the wheel nut so as not to rotate relative to it; an arrow plate that is provided through a fixing ring shaft that coincides with each of the aforementioned axes and has an arrow plate insertion hole through which the wheel nut is inserted coaxially and is mounted on the arrow fixing ring so as not to rotate relative to it; and a stopper member that holds the arrow fixing ring and the arrow plate, wherein the arrow fixing ring has a fixing ring recessed portion in which m peaks and m valleys are arranged alternately around the fixing ring shaft, and the arrow plate has an arrow plate recessed portion in which m peaks and m valleys are arranged alternately around the arrow shaft and recessed portions that fit together with the fixing ring recessed portion.

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