Screw

Abstract

To provide a screw that restrains an increase in rotation torque caused by a foreign body having entered between the screw and a nut, and allows stable rotation.SOLUTION: A screw 51 comprises a male thread part 54. A nut 52 is screwed to the male thread part 54 of the screw 51. When the screw 51 is axially rotated, the nut 52 is moved in an axial direction of the screw 51. A concave groove 542 extending in an axial direction and having a predetermined length is formed in the male thread part 54 of the screw 51. The concave groove 542 is made to communicate with thread roots adjacent in an axial direction of the male thread part 54, is constituted by cutting a part in the axial rotation direction of a thread of the male thread part 54, and is formed so as to be longer than at least a dimension in an axial direction of the nut 52.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a screw (male thread) onto which a nut is threaded, and relates to a screw suitable for use in, for example, an aiming device for adjusting the optical axis direction of a vehicle lamp. [Background technology]

[0002] Some vehicle lamps, such as those for automobiles, are equipped with an aiming device for adjusting the direction of light emission when the lamp is turned on, and some of these aiming devices use a screw. For example, in the lamp disclosed in Patent Document 1, a reflector of a lamp unit is tiltably supported within a lamp housing, a rotatable aiming screw is provided in the lamp housing, and an aiming nut (push-on fix) threaded onto the aiming screw is provided on the reflector. With this aiming device, rotating the aiming screw moves the aiming nut in the axial direction of the aiming screw, and a part of the reflector moves together with the aiming nut. This tilts the reflector around the fulcrum on which it is supported, enabling the aiming of the lamp unit to be adjusted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-42043 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, the aiming screw is disposed inside the lamp housing, but minute foreign matter may adhere to the surface of the male thread portion due to air movement inside the lamp housing, etc. Alternatively, when the aiming screw is rotated, foreign matter such as wear powder may be generated at the contact surface with the nut that is threaded onto the aiming screw. As a result, when the aiming screw is rotated, the foreign matter may hinder smooth movement at the contact surface between the male thread portion and the female thread portion. In such a situation, the rotational torque when rotating the aiming screw increases, impairing stable rotation of the aiming screw and reducing the reliability of the aiming device.

[0005] An object of the present invention is to provide a screw that suppresses an increase in rotational torque due to foreign matter entering between the screw and the nut, thereby enabling stable screw rotation. [Means for solving the problem]

[0006] The present invention relates to a screw having a male thread portion, a nut having a female thread portion threadedly engaged with the male thread portion, and the nut being moved in the axial direction of the screw when the screw is rotated, and the male thread portion of the screw has a groove formed therein extending in the axial direction and having a required length. This groove is preferably configured to connect adjacent thread roots in the axial direction of the male thread portion. For example, the groove is configured by removing a portion of the thread of the male thread portion in the axial direction. Furthermore, the groove is formed to be at least longer than the axial dimension of the nut. [Effects of the Invention]

[0007] According to the present invention, foreign matter that has formed on the contact surface between the male thread portion and the nut threaded thereto can be moved to the groove as the screw rotates and removed from the contact surface. Furthermore, the foreign matter can be expelled from the screw to the outside through the groove. This prevents foreign matter from interfering with the smooth operation of the contact surface between the male thread portion and the female thread portion when the screw rotates, prevents an increase in rotational torque when the screw is rotated, and enables the screw to be rotated in a stable state. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a longitudinal sectional view of an automobile headlamp to which the present invention is applied. [Figure 2] FIG. 1 is a schematic perspective view of a headlamp. [Figure 3] FIG. [Figure 4] FIG. 1 is an enlarged perspective view of an aiming screw and an aiming nut. [Figure 5] FIG. 4 is a cross-sectional view showing the state in which the aiming screw and the aiming nut are screwed together. [Figure 6] FIG. 10 is a perspective view of a modified example of the aiming screw. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic perspective view of an automobile (CAR) equipped with a vehicle lamp having a screw according to the present invention. Front lamps FL are equipped on the left and right sides of the front of the body of the automobile (CAR). Fig. 1 shows a partially cutaway perspective view of the left front lamp FL, and the right front lamp FL has a symmetrical configuration. The front lamp FL has two lamp units CL and HL housed in a lamp housing 100 composed of a lamp body 101 with an opening at the front and a translucent cover 102 attached to the opening of the lamp body 101.

[0010] The upper lamp unit CL is configured as a clearance lamp, turn signal lamp, or DRL (Daytime Running Lamp) using a light guide, or as a lamp that combines these functions. The lower lamp unit HL is configured as a headlamp to which the present invention is applied. In the following, the front-to-rear direction refers to the direction from the front to the rear of the headlamp HL, and the left-to-right direction refers to the direction along the left and right when viewing the headlamp HL from the front.

[0011] Fig. 2 is an external perspective view of the headlamp (headlamp unit) HL shown in Fig. 1, and Fig. 3 is a longitudinal sectional view of the headlamp installed in a lamp housing 100. Note that Fig. 3 shows some of the configuration in an exaggerated manner. The headlamp HL is configured as a projector-type lamp unit, and includes an integrally assembled heat sink 10 and lens holder 20, with a light source 1 mounted on the heat sink 10 and a projection optical system 2 incorporated within the lens holder 20. When the light source 1 emits light, the light emitted from the light source 1 is projected by the projection optical system 2 toward the area ahead of the automobile CAR, providing illumination with a required light distribution pattern.

[0012] The headlamp HL uses an LED array 12, in which multiple LEDs (light-emitting diodes) are arranged in a matrix, as its light source 1, mounted on a substrate 11 on which a power supply circuit (not shown) is constructed. The LED array 12 forms a desired light pattern by selectively emitting light from the multiple LEDs. The projection optical system 2 includes a projection lens 21 that projects the desired light pattern formed by the light source 1 as a light distribution pattern, and this projection lens 21 is incorporated into a lens holder 20. Although not shown, the headlamp HL may also be configured as a reflector-type lamp unit that includes a reflector that reflects light from the light source to provide illumination with a desired light distribution pattern.

[0013] A flange plate 30 is integrally provided on the lens holder 20, and an aiming mechanism 3 is provided on this flange plate 30. This aiming mechanism 3 includes a fulcrum portion 4, a vertical aiming portion 5, and a horizontal aiming portion 6. As will be described later, by driving these aiming portions 5 and 6, the entire headlamp HL can be tilted up and down and left and right around the fulcrum portion 4, thereby adjusting the direction of the illumination optical axis Lx of the headlamp HL.

[0014] In the aiming device 3, the fulcrum portion 4 is disposed at the lower right side when viewed from the front of the flange plate 30, and is configured as a fulcrum when the headlamp HL tilts. This fulcrum portion 4 has a support rod 41 whose base end 42 is fixedly supported by the lamp body 101 and which has a spherical ball 43 at its tip. The ball 43 of this support rod 41 is fitted into a ball socket 44 supported by the flange plate 30 to form a ball joint. The ball socket 44 is supported by a snap portion 45 provided at one end which fits into a hole 31 provided in the flange plate 30. As a result, the headlamp HL is supported by the lamp body 101, i.e., the lamp housing 100, so that it can tilt up and down and left and right with the ball joint 42 as a fulcrum.

[0015] The upper and lower aiming sections 5 are disposed on the flange plate 30 at a position vertically above the fulcrum section 4, and the left and right aiming sections 6 are disposed on the flange plate 30 at a position horizontally to the left of the fulcrum section 4. These aiming sections 5, 6 are each composed of an aiming screw 51, 62 that passes through the rear surface of the lamp body 101 and an aiming nut 52, 62 that is screwed onto the male thread portion of the aiming screw 51, 61. Both have the same basic configuration, in which the aiming nuts 52, 62 are moved in the front-to-rear direction by rotating the aiming screw 51, 61. Here, the upper and lower aiming sections 5 will be described.

[0016] Figure 3 shows the upper and lower aiming portions 5, and Figure 4 is an enlarged perspective view of the aiming screw 51 and the aiming nut 52. The aiming screw 51 is molded from a resin such as nylon, and has a crown gear 53 as an operating portion at its base end, and a male thread portion 54 of a required length formed at its tip end. In addition, a journal portion 55 is formed between the crown gear 53 and the male thread portion 54.

[0017] The pivotal support portion 55 is inserted from the outside into a sleeve-shaped boss hole 103 provided on the rear surface of the lamp body 101 and is supported in a rotatable manner in the boss hole 103. An annular seal ring 551 is attached to a portion of the base end of the pivotal support portion 55, ensuring waterproofing between the inner surface of the boss hole 103 and the pivotal support portion 55. A pair of blade-shaped locking pieces 552 that expand in diameter toward the base end are provided on the tip end side of the pivotal support portion 55, and when the aiming screw 51 is inserted into the boss hole 103 from the tip end side, the ends of each locking piece 552 elastically engage with the front end of the boss hole 103. As a result, the pivotal support portion 55 is rotatable within the boss hole 103 but is supported in an axially locked state.

[0018] The crown gear 53 serving as the operating part is arranged so that, with the aiming screw 51 supported, its teeth 531 face the rear surface of the lamp body 101 with a required gap between them, and the teeth 531 mesh with a cross head screwdriver inserted into this gap. As a result, when the cross head screwdriver is rotated, the crown gear 53 is rotated and the aiming screw 51 is rotated. Note that this operating part may have a hexagonal recess formed on its base end surface, and the aiming screw 51 may be rotated by fitting a hexagonal wrench into this hexagonal recess.

[0019] A portion of the tip of the male thread portion 54 is formed as a thin-diameter guide portion 541, but the portion further to the base end is configured as a male thread with a uniform diameter. The male thread portion 54 will be described in detail later, but by using the guide portion 541, it becomes easy to thread the aiming nut 52 onto the male thread portion 54, and also prevents the aiming nut 52 and the aiming screw 51 from coming apart.

[0020] The aiming nut 52 is formed as a square tubular member having a female threaded portion 56 inside which the male threaded portion 54 of the aiming screw 51 is screwed. A pair of hook-shaped snap pieces 57 are formed integrally with the aiming nut 52, and these snap pieces 57 are inserted into and fitted into the square holes 32 of the flange plate 30. As a result, the aiming nut 52 is supported integrally with the flange plate 30 at least in the axial direction and the front-to-rear direction.

[0021] As shown in an enlarged view of a portion in Fig. 4, grooves 542, where the threads have been removed, are formed in the male thread portion 54 of the aiming screw 51 at one or more locations around the axis, i.e., in the circumferential direction, in at least a portion of the length direction. These grooves 542 are formed in two locations in the circumferential direction, i.e., two locations facing each other in the radial direction, over substantially the entire length of the male thread portion 54 excluding the guide portion 541, in this case excluding a portion on the base end side. Note that Fig. 4 shows the groove 542 on the near side, and the groove on the opposite side is not shown.

[0022] 5(a) is a cross-sectional view perpendicular to the axial direction of the male thread portion 54 of the aiming screw 51. Grooves 542 are formed in two locations in the circumferential direction of the male thread portion 54, and each groove 542 is formed in a semicircular shape with a depth equal to the height dimension (radial dimension) of the thread 543 of the male thread portion 54. Therefore, no thread 543 is present in the location where the groove 542 is provided, and due to this groove 542, thread valleys 543 adjacent to each other in the axial direction in the male thread portion 54 are in communication with each other via the groove 542.

[0023] Here, the cross-sectional shape and dimensions of the recessed groove 542 when viewed from the axial direction of the aiming screw 51, particularly the dimensions around the axis of the aiming screw 51 and the dimensions in the radial direction, are not particularly limited as long as they do not impair the threaded engagement between the aiming screw 51 and the aiming nut 52. Here, the cross-sectional shape is close to semicircular, but as will be described later, any shape can be used as long as it is capable of accommodating foreign matter, and the dimensions can also be such that the foreign matter can be accommodated and moved.

[0024] Typically, the aiming screw 51 is molded from resin using a mold, and the groove 542 can be formed at the same time as the aiming screw 51 is molded from resin. In Fig. 4, molding is performed with molds arranged on the left and right sides of the aiming screw 51, and by forming a protrusion corresponding to the groove 542 in each mold, the groove 542 can be formed on both the left and right sides of the male thread portion 54 of the aiming screw 51. In this case, parting lines PL are formed on the top and bottom of the circumferential surface of the aiming screw 51.

[0025] In the aiming device 3 configured as described above, the headlamp HL is supported by the lamp body 101 at the fulcrum portion 4, and is also supported by the upper and lower aiming portions 5 and the left and right aiming portions 6. In the upper and lower aiming portions 5 and the left and right aiming portions 6, aiming screws 51, 61 are journaled on the lamp body 101, and aiming nuts 52, 62 supported on the flange plate 30 are screwed onto the aiming screws 51, 61, thereby achieving support. In the upper and lower aiming portions 5, the journal portion 55 of the aiming screw 51 is journaled in a boss hole 103 of the lamp body 101, and the male thread portion 54 is guided by a guide portion 541 and inserted into and screwed onto the female thread portion 56 of the aiming nut 52. The same applies to the left and right aiming portions 6.

[0026] Then, by rotating the aiming screw 51 as described above using the operating portion, i.e., the crown gear 53, on the rear side of the lamp body 101, the aiming nut 52 threaded onto the male thread portion 54 is slid in the front-rear direction along the axial direction of the aiming screw 51. As a result, the upper portion of the flange plate 30 moves in the front-rear direction integrally with the aiming nut 52, and the headlamp HL is tilted up and down around the fulcrum portion 4, adjusting the light emission direction of the headlamp HL in the up-down direction. Similarly, by operating the left-right aiming portion 6, the light emission direction of the headlamp HL is adjusted in the left-right direction.

[0027] In either of the aiming portions 5, 6, foreign matter may enter between the aiming screw 51, 61 and the aiming nut 52, 62, for example, between the male thread portion 54 and the female thread portion 56 in the aiming screw 51. Alternatively, the rotation of the aiming screw 51 may cause wear on the contact surfaces of the male thread portion 54 and the female thread portion 56, resulting in the generation of foreign matter such as wear debris. This increases the frictional resistance on the contact surfaces of the male thread portion 54 and the female thread portion 56, hindering smooth thread engagement between the male thread portion 54 and the female thread portion 56, increasing the load when the aiming screw 51 is rotated, i.e., the rotational torque, and reducing operability in aiming adjustment.

[0028] 5(b) and 5(c) are cross-sectional views of the male thread portion 54 and the female thread portion 56 threadedly engaged in different directions, and in the male thread portion 54, adjacent thread valleys 543 in the axial direction are communicated via the groove 542. As a result, foreign matter X adhering to the contact surface between the male thread portion 54 and the female thread portion 56 is moved circumferentially along the thread 543 as the aiming screw 51 rotates, and is accommodated in the groove 542 when it reaches the groove 542. This removes the foreign matter X from the contact surface, reducing frictional resistance at the contact surface and preventing an increase in rotational torque when the aiming screw 51 rotates. The foreign matter X moved into the groove 542 may remain in the groove 542, or may be moved axially within the groove 542 and then expelled from the end of the groove 542.

[0029] In the present invention, it is preferable that the axial length of the recessed groove 542 is at least longer than the axial length of the aiming nut 52. In other words, it is preferable that at least one axial end of the recessed groove 542 is exposed from the end of the aiming nut 52 when the aiming nut 52 is threaded onto the aiming screw 51. This improves the effect of removing foreign matter housed in the recessed groove 542.

[0030] In addition, in an aiming screw molded from resin, a parting line created by the molding die is formed along the entire length of the aiming screw, including the male thread portion, but as shown in Figure 6(a), the recessed groove 542 may be formed in a position that overlaps with the parting line PL. In this way, the parting line PL is formed within the recessed groove 542, which prevents the parting line PL from appearing on the surface of the male thread portion 54, allowing for smooth threading of the male thread portion 54 and the female thread portion 56 of the aiming nut 52.

[0031] In the present invention, if foreign matter adhering to the male thread portion of the aiming screw is configured to move along the thread and be accommodated in the groove, the foreign matter can be removed from between the contact surfaces. Therefore, the groove does not need to be continuous in the axial direction of the aiming screw. For example, as shown in FIG. 6( b), as long as a groove 542 is formed in a portion of the male thread portion 54 of the aiming screw 51 in the axial direction, the groove 542 may be formed intermittently in the axial direction of the aiming screw 51. In this example, multiple grooves 542 are formed intermittently at different positions in the axial direction and the axial direction. Furthermore, although not shown, the shape of the groove in the direction perpendicular to the axial direction of the aiming screw may be rectangular or another shape.

[0032] In the embodiment, the present invention is applied to an aiming screw of an aiming mechanism. However, it may also be applied to a screw used in a leveling mechanism that maintains a constant lamp illumination angle in response to changes in the inclination angle of the vehicle body, particularly the vehicle's pitch angle. Although not shown, for example, a leveling screw may be provided on a leveling actuator supported on a lamp housing, and a leveling nut supported on a headlamp may be threadedly engaged with this leveling screw. The leveling actuator is operated to rotate the leveling screw, thereby controlling and changing the vertical angle of the headlamp. In this leveling mechanism, too, by providing a groove in the male thread of the leveling screw, an increase in load due to foreign matter when the leveling screw rotates can be prevented, ensuring smooth operation. [Explanation of symbols]

[0033] 1 light source 2 Projection optical system 3 Aiming mechanism 4 Support part 5 Upper and lower aiming section 6 Left and right aiming section 10 Heatsink 12 Light source (LED array) 21 Projection lens 51 Aiming Screw 52 Aiming Nut 53 Operating unit (crown gear) 54 Male thread 55 axis branch 56 Female thread 61 Aiming Screw 62 Aiming Nut 100 Lamp Housing 101 Lamp body 542 groove 543 thread HL headlamp (headlamp unit) X Foreign object

Claims

1. A screw having a male thread portion, a nut threaded onto the male thread portion, and the nut being moved in the axial direction of the screw when the screw is rotated, characterized in that a groove of a required length extending in the axial direction is formed in the male thread portion of the screw.

2. The screw according to claim 1 , wherein the grooves communicate with thread roots adjacent in the axial direction of the male thread portion.

3. The screw according to claim 2, wherein the groove is formed by removing a portion of the thread of the male screw portion in the axial direction.

4. The screw according to claim 1 , wherein the groove is longer than at least the axial dimension of the nut.

5. The screw according to claim 1, wherein the screw has an operating portion at a base end thereof, and is axially rotated at the operating portion.

6. 6. The screw according to claim 1, wherein the screw is an aiming screw that constitutes an aiming mechanism of a vehicle lamp, and the nut is an aiming nut that is threaded onto the aiming screw to tilt the vehicle lamp.

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