Patent Description:
Usually, a vehicle headlamp is provided with an optical axis adjustment mechanism in order to adjust an optical axis of a light source. There is known an optical axis adjustment mechanism configured to include an aiming screw (adjustment shaft), a nut member (pivot) with which a screw unit of the adjustment shaft is screwed, and a bearing member (case) that bears a main body (sphere unit) having a spherical outer peripheral surface of the pivot (see <CIT>). The pivot is also provided with a sliding guide unit in order to absorb a vibrational load and the like of a vehicle. The pivot and the case are made of plastic resin and formed by injection molding.

However, in the structure of the pivot described in FIG. <NUM> of <CIT>, upper and lower portions of the sphere unit cannot be borne by the case, so an area of a receiving surface of the case cannot be expanded. Therefore, an allowable load of the case cannot be increased, and the case may be broken. On the other hand, in the structure of the pivot described in FIG. <NUM> of <CIT>, upper and lower portions of the sphere unit can be borne by the case, but the sliding guide unit is coupled by a leg unit offset from a center of the sphere unit and a moment acts between the sphere unit and the sliding guide unit. As a result, breakage may occur between the sphere unit and the leg unit. <CIT> shows a related pivot. <CIT> discloses a regulation element for use in various vehicles. The regulation element is intended for adjusting the position of a light module with respect to position of the casing, and consists of a regulating screw, which is connected to the casing as well as of a nut, which may be set on the light module rim by means of bearing shoulders.

In view of the above problems, we have appreciated that it would be desirable to provide a compact pivot, a bearing mechanism, and a vehicle headlamp, by which it is possible to efficiently transmit a load acting on the pivot to a case that bears the pivot.

According to the present invention, it is possible to provide a compact pivot, a bearing mechanism, and a vehicle headlamp, by which it is possible to efficiently transmit a load acting on the pivot to a case that bears the pivot.

With reference to the drawings, an embodiment of the present invention will be described in detail, below. It is noted that the same members are denoted by the same reference symbols throughout the embodiment herein. In addition, front and rear, left and right, and up and down indicate a direction when a vehicle headlamp is viewed from a front side on a lens side.

First, before a pivot <NUM> according to the embodiment of the present invention is described, a vehicle headlamp <NUM> will be described. <FIG> is a perspective view illustrating a vehicle headlamp provided with a pivot according to the embodiment of the present invention.

The headlamp <NUM> illustrated in <FIG> is designed so that an optical axis of a light source <NUM> is adjusted when a reflector <NUM> provided inside a lamp housing <NUM> swings, and includes the lamp housing <NUM>, the reflector <NUM>, and an optical axis adjustment mechanism <NUM>.

The lamp housing <NUM> is in a box shape with its front side being open, and is made of a plastic resin. In the lamp housing <NUM>, a lens (outer lens) <NUM> is mounted to the front opening.

Further, the lamp housing <NUM> has a guide unit <NUM> to suspend the optical axis adjustment mechanism <NUM>. The guide unit <NUM> includes a pair of left and right projection pieces projecting, in an L shape, inward from a ceiling surface of a peripheral wall of the lamp housing <NUM>, as viewed from the front side, where each of the guide units <NUM> is formed in a dovetail groove shape. However, the guide unit <NUM> may be formed on a bottom surface or on a side to mount the optical axis adjustment mechanism <NUM>.

The lens <NUM> transmits direct light or reflected light from the light source <NUM>.

Next, the reflector <NUM> functions as a holding member to which the light source <NUM> is attached at a rear center thereof, and is formed of a curved surface to reflect light from the light source <NUM> forward. Therefore, the reflector <NUM> is made of a plastic resin, and the inside thereof is a reflective surface on which silver plating or silver deposition is performed.

Further, the reflector <NUM> has an attachment unit <NUM> that attaches the optical axis adjustment mechanism <NUM>. The attachment unit <NUM> is in a bracket shape extending rearward from the reflector <NUM>, and has a rectangular opening at its distal end.

A discharge lamp such as a metal halide lamp or an LED element is employed for the light source <NUM>.

Here, the optical axis adjustment mechanism <NUM> will be described.

The optical axis adjustment mechanism <NUM> adjusts the optical axis of the light source <NUM>, and includes two optical axis adjustment mechanisms <NUM>, that is, those at an upper left and an upper right on a rear side of the reflector <NUM>, when the headlamp <NUM> is viewed from the front side (see <FIG>). One end side on the front side of the optical axis adjustment mechanism <NUM> is attached to the reflector <NUM> and the other end side on the rear side thereof is attached to the lamp housing <NUM>. It is noted that a swinging fulcrum for adjusting the optical axis is provided at a lower left on the rear side of the reflector <NUM>.

The optical axis adjustment mechanism <NUM> is configured to include a shaft member <NUM> as an adjustment shaft, the pivot <NUM> that holds the shaft member <NUM>, and a case <NUM> that bears the pivot <NUM>.

The shaft member <NUM> is a substantially round rod-like member, and is made of a plastic resin. On a front side of the shaft member <NUM>, a male screw unit <NUM> is formed on an outer periphery of the shaft member <NUM>. On the other hand, on a rear side of the shaft member <NUM>, an unillustrated operated unit is formed to allow an operator to rotate the shaft member <NUM> by using a tool or the like, and the shaft member <NUM> is rotatably supported so that the operated unit is exposed to the outside of the lamp housing <NUM>.

<FIG> is a rear perspective illustrating a pivot according to the embodiment of the present invention, and <FIG> illustrate the pivot according to the embodiment of the present invention, where <FIG> is a front view and <FIG> is a side view. In addition, in <FIG>, a right direction is a front direction of the vehicle.

The pivot <NUM> includes a sphere unit <NUM> that holds the shaft member <NUM> and a sliding guide unit <NUM> to be suspended or mounted on the guide unit <NUM> formed in the lamp housing <NUM>, and is made of a plastic resin (see <FIG>).

An outer periphery of the sphere unit <NUM> is generally spherical, a through hole <NUM> to pass through a center C is formed inside the sphere unit <NUM>, and both sides in an axial direction of the through hole <NUM> are chamfered. Moreover, on an inner periphery of the through hole <NUM>, a female screw unit <NUM> with which the male screw unit <NUM> of the shaft member <NUM> is screwed is formed (see <FIG>). If the male screw unit <NUM> of the shaft member <NUM> is screwed into the female screw unit <NUM> of the through hole <NUM> and held in the sphere unit <NUM>, when the shaft member <NUM> is rotated, a screw structure including the male screw unit <NUM> and the female screw unit <NUM> allows the pivot <NUM> to move relatively back and forth.

Further, the sphere unit <NUM> is coupled to the sliding guide unit <NUM> via the two leg units <NUM>. An outer surface of the sphere unit <NUM> other than a region where the two leg units <NUM> are coupled is finished to be a smooth surface to serve as a received surface borne by a below-described case <NUM>.

Next, the sliding guide unit <NUM> includes a tabular plate <NUM> and an elastic piece <NUM>. The plate <NUM> is designed so that the two leg units <NUM> are coupled to a top surface 21a being one surface, and the elastic piece <NUM> is coupled to a bottom surface 21b being the other surface.

Further, the end surface of the plate <NUM> at one (left) side of in the axial direction of the through hole <NUM> is substantially flush with the chamfered outer edge of the sphere unit <NUM>, and the end surface of the plate <NUM> at the other (right) side thereof extends to a position offset outside of the chamfered outer edge of the sphere unit <NUM>. Moreover, a region outside the two leg units <NUM> of the top surface 21a is finished to be a smooth surface to facilitate sliding when suspended or mounted on the guide unit <NUM> of the lamp housing <NUM>.

The elastic piece <NUM> includes at least two convex units 22a projecting toward the side opposite to the sphere unit <NUM>. The elastic pieces <NUM> have the same width (length in a front-rear direction) as those of left and right sides of the plate <NUM>, extend toward the side opposite to the sphere unit <NUM>, and have its center narrowed in the front-rear direction. The convex units 22a are located on both sides across a center portion of the elastic piece <NUM>. Further, a surface of each of the convex unit 22a opposite to the sphere unit <NUM> is finished to be a smooth surface to facilitate sliding when suspended or mounted to the guide unit <NUM>.

The two leg units <NUM> are coupled to the above-described sphere unit <NUM> and sliding guide unit <NUM>. The two leg units <NUM> extend from the left and right of the sphere unit <NUM> toward the sliding guide unit <NUM>, as viewed from the front, and an area surrounded by the sphere unit <NUM>, the sliding guide unit <NUM>, and the two leg units <NUM> forms a space S (see <FIG> and <FIG>).

Further, the two leg units <NUM> are formed to overlap a plane L that is orthogonal to the axial direction of the through hole <NUM> of the sphere unit <NUM> and passes through the center C (see <FIG>). The end surface of each of the leg units <NUM> at one (left) side in the axial direction of the through hole <NUM> is substantially flush with the chamfered outer edge of the sphere unit <NUM>, and the end surface of each of the leg units <NUM> at the other (right) side thereof is further curved toward the other side toward the sliding guide unit <NUM> from a position offset outward of the plane L. When the two leg units <NUM> are overlapped on such a plane L, the pivot <NUM> can be formed with a simple mold even in a case of the pivot <NUM> including the sphere unit <NUM> because a mold can be manufactured with no undercut by using the plane L as a parting surface. It is noted that a reinforcement unit <NUM> is integrally formed between the two leg units <NUM> and the top surface 21a of the plate <NUM>.

<FIG> is a rear perspective view illustrating a case, and <FIG>, and <FIG> illustrate a developed state of the case, where <FIG> is a plan view, <FIG> is a front view, and <FIG> is a side view.

The case <NUM> bears an outer surface of the sphere unit <NUM> of the pivot <NUM> with receiving surfaces <NUM> and <NUM>, and is formed of two half-split structures <NUM> and <NUM> (see <FIG>). The two half-split structures <NUM> and <NUM> are made of a plastic resin, and are further formed into an integrally molded article coupled to each other. In the case <NUM>, attached units <NUM> and <NUM> to be attached to the attachment unit <NUM> of the reflector <NUM> are formed on the front side and the receiving surfaces <NUM> and <NUM> are formed on the rear side.

The two half-split structures <NUM> and <NUM> are locked together with at least three locking means <NUM> and <NUM> when assembled to bear the sphere unit <NUM>. It is noted that the two half-split structures <NUM> and <NUM> of the present embodiment may be formed separately, and in this case, the number of the locking means <NUM> and <NUM> is not limited to three.

First, the half-split structure <NUM> bears an upper side of the sphere unit <NUM> opposite to the sliding guide unit <NUM> with the substantially hemispherical receiving surface <NUM> (see <FIG>). The receiving surface <NUM> is finished to be a smooth surface to facilitate sliding when bearing the sphere unit <NUM>.

The locking means 42a of the half-split structure <NUM> has an opening and is formed on an end side being a front side when assembled to the half-split structure <NUM> while the locking means 42b and 42c have protrusions and are formed on the left and right.

Further, a positioning means 43b is a cylindrical shape with a distal end thereof cut, and a positioning means 43c is a circular hole, each of which is formed on either left or right of the attached unit <NUM>.

Next, the half-split structure <NUM> bears a lower side of the sphere unit <NUM> on the side of the sliding guide unit <NUM> by the substantially hemispherical receiving surface <NUM> (see <FIG>). However, the lower side of the sphere unit <NUM> is coupled to the two leg units <NUM>, and thus, the receiving surface <NUM> is divided into three regions, that is, a receiving surface 51a for bearing a lower portion of the sphere unit <NUM>, a receiving surface 51b and a receiving surface 51c for bearing left and right portions of the sphere unit <NUM>. The receiving surface 51a is formed in a size to be inserted into the space S of the pivot <NUM>. Further, a gap G is each formed between the receiving surface 51a and the receiving surface 51b and between the receiving surface 51a and the receiving surface 51c so that the leg unit <NUM> can be inserted. The receiving surface <NUM> is finished to be a smooth surface to facilitate sliding when bearing the sphere unit <NUM>.

The locking means 52a formed on the receiving surface 51a of the half-split structure <NUM> includes a projection, while the locking means 52b and 52c respectively formed on the receiving surfaces 51b and 51c include an opening, where the locking means 52a, 52b, and 52c are formed at positions corresponding to the locking means 42a, 42b, and 42c of the half-split structure <NUM>. Further, a positioning means 53b is a circular hole, and a positioning means 53c is in a cylindrical shape with a distal end thereof cut, each of which is formed at a position corresponding to each of the positioning means 43b and 43c of the half-split structure <NUM>.

The attached units <NUM> and <NUM> are hollow square pillars in an assembled state, and have locking claws <NUM> and <NUM>, respectively. When the attached units <NUM> and <NUM> are inserted into the rectangular openings of the attachment unit <NUM> of the reflector <NUM>, the locking claws <NUM> and <NUM> are locked in the openings and attached to the reflector <NUM> (see <FIG>).

A method of assembling a bearing mechanism <NUM> that bears the pivot <NUM> by the case <NUM> will be described. <FIG> is a schematic view illustrating the method of assembling the bearing mechanism.

First, the case <NUM> in a developed state is set while placing the half-split structure <NUM> at the head, and the receiving surface 51a of the half-split structure <NUM> is inserted into the space S of the pivot <NUM> and the two leg units <NUM> are inserted into the gap G.

Next, the half-split structures <NUM> is bent toward the half-split structure <NUM>, the pillar of the positioning means 43b is inserted into the circular hole of the positioning means 53b, and the pillar of the positioning means 53c is inserted into the circular hole of the positioning means 43c. Further, protrusions of the locking means 42b and 42c are respectively inserted into openings of the locking means 52b and 52c, and a projection of the locking means 52a is inserted into an opening of the locking means 42a.

Thus, the two half-split structures <NUM> and <NUM> of the case <NUM> are positioned relative to each other and the case <NUM> is locked to bear the pivot <NUM>.

It is noted that a relationship between the projections and the openings of the locking means <NUM> and <NUM> and a relationship between the positioning means <NUM> and <NUM> are relative to each other, and therefore, these may be interchangeably formed on the opposite side, and may be another locking structure.

The shaft member <NUM> is attached, as an adjustment shaft, to the bearing mechanism <NUM> to configure the optical axis adjustment mechanism <NUM>. In other words, when the male screw unit <NUM> of the shaft member <NUM> is screwed into the female screw unit <NUM> of the through hole <NUM> of the pivot <NUM>, the shaft member <NUM> is attached to the bearing mechanism <NUM> to configure the optical axis adjustment mechanism <NUM>.

Further, when the optical axis adjustment mechanism <NUM> is attached to the headlamp <NUM>, the optical axis of the light source <NUM> can be adjusted.

<FIG> is a side cross sectional view illustrating a mounting state of the optical axis adjustment mechanism and <FIG> is a rear view of the same viewed from a rear side.

As illustrated in <FIG>, the optical axis adjustment mechanism <NUM> is suspended from the guide unit <NUM> of the lamp housing <NUM> and attached to the attachment unit <NUM> of the reflector <NUM>. Specifically, the sliding guide unit <NUM> of the pivot <NUM> is slidably locked into a dovetail groove of the guide unit <NUM>, and the attached units <NUM> and <NUM> of the case <NUM> are inserted into a rectangular opening of the attachment unit <NUM> to be attached non-rotatably, and are prevented from removal by the locking claws <NUM> and <NUM>.

Next, when an operator operates an operated unit with a tool to rotate clockwise the shaft member <NUM> of the optical axis adjustment mechanism <NUM> at an upper right of the headlamp <NUM> when viewed from the front, the male screw unit <NUM> formed on an outer periphery of the shaft member <NUM> is simultaneously rotated and the pivot <NUM> having the female screw unit <NUM> to be screwed into the male screw unit <NUM> moves axially rearward, and the reflector <NUM> swings obliquely upward to the right. Thus, each optical axis adjustment mechanism <NUM> swings the reflector <NUM> in the vertical and horizontal directions to adjust the optical axis of the light source <NUM>.

As described above, the pivot <NUM> of the embodiment includes the sphere unit <NUM> formed such that the through hole <NUM> capable of holding the shaft member <NUM> passes through the center C of the sphere unit <NUM>, and the sliding guide unit <NUM> to be suspended or mounted, where the sphere unit <NUM> is coupled to the sliding guide unit <NUM> via the two leg units <NUM>. As a result, when the pivot <NUM> is suspended or mounted, the received surface of the sphere unit <NUM> can be formed also in a direction where a load is applied, that is, in a vertical direction, and thus, even the compact pivot <NUM> can efficiently transmit the load acting on the pivot <NUM> to the case <NUM> that bears the pivot <NUM>.

In the embodiment, the two leg units <NUM> are formed to overlap the plane L running perpendicular to the axial direction of the through hole <NUM> and passing through the center C. As a result, also when the pivot <NUM> including the sphere unit <NUM>, the sliding guide unit <NUM>, and the leg units <NUM> is formed by injection molding, in a molding mold, there is no undercut between the sphere unit <NUM> of the pivot <NUM> and the sliding guide unit <NUM> thereof, and thus, no complicated structure is necessary, a cost of the mold can be reduced, and the number of molding steps can also be reduced.

In the embodiment, the sliding guide unit <NUM> includes the tabular plate <NUM>, and the elastic piece <NUM>, wherein the plate <NUM> is designed so that the two leg units <NUM> are coupled to the top surface 21a being one surface, and the elastic piece <NUM> is coupled to the bottom surface 21b being the other surface. As a result, when the pivot <NUM> is suspended or mounted, even if a load or an impact is applied, the elastic piece <NUM> can bend to absorb the load or the impact.

In the embodiment, the elastic piece <NUM> includes at least two convex units 22a projecting toward the side opposite to the sphere unit <NUM>. As a result, when the pivot <NUM> is suspended or mounted, even if a load or an impact is applied, the load or the impact can be distributed, and thus, an allowable strength of the elastic piece <NUM> of the sliding guide unit <NUM> of the pivot <NUM> can be increased.

The bearing mechanism <NUM> of the embodiment includes the pivot <NUM> and the case <NUM> that bears the pivot <NUM>, and the case <NUM> that bears the sphere unit <NUM> of the pivot <NUM> is formed of the two half-split structures <NUM> and <NUM> having the receiving surfaces <NUM> and <NUM> for bearing the sphere unit <NUM>, and the two half-split structures <NUM> and <NUM> are locked together by at least three locking means <NUM> and <NUM>. As a result, even if the pivot <NUM> has the received surfaces of the sphere unit <NUM> in the vertical direction and the case <NUM> is formed of the two half-split structures <NUM> and <NUM>, when the pivot <NUM> is borne by the case <NUM>, it is possible to prevent a case where the two half-split structures <NUM> and <NUM> of the case <NUM> are unlocked and developed.

The vehicle headlamp <NUM> according to the embodiment includes the lamp housing <NUM> on which the outer lens <NUM> is mounted, the reflector (holding member) <NUM> to which the light source <NUM> is attached, and the optical axis adjustment mechanism <NUM> that adjusts an optical axis, wherein the lamp housing <NUM> has the guide unit <NUM> to suspend or mount the sliding guide unit <NUM> of the pivot <NUM>, the reflector <NUM> has the attachment unit <NUM> that attaches the case <NUM>, the optical axis adjustment mechanisms <NUM> includes the shaft member <NUM> as an adjustment shaft, the pivot <NUM>, the case <NUM> that bears the sphere unit <NUM> of the pivot <NUM>, the pivot <NUM> holds the shaft member <NUM> in the through hole <NUM> by a screw structure, and the case <NUM> has the attached units <NUM> and <NUM> to be attached to the attachment unit <NUM>. As a result, even if a vehicle vibrates up and down and the like, a load or an impact can be absorbed by the sliding guide unit <NUM>, and therefore, the optical axis adjustment mechanism <NUM> is not broken and is durable for use with the headlamp <NUM>.

<FIG> is a front view illustrating a pivot having an elastic piece according to a modification.

In the above embodiment, the elastic piece <NUM> includes the two convex units 22a. However, as illustrated in <FIG>, the elastic piece <NUM> may have three convex units 22a. If there are two convex units 22a of the elastic piece <NUM>, when a load is applied to the convex units 22a, stress may be concentrated at a center because a center side is recessed. If the pivot <NUM> is formed by injection molding, a gate is formed near the sphere unit <NUM>, and thus, at a portion of the elastic piece <NUM>, a weld line formed when molten resin fronts meet is generated near the center, and as a result, a position where the stress concentrates and a position of the weld line substantially coincide, and a sufficient strength may not be secured.

However, the elastic piece <NUM> of the modification includes the three convex units 22a to form two concave units, and thus, the stress by the load applied to the convex units 22a disperses near the two concave units. Therefore, the allowable strength of the sliding guide unit <NUM> of the pivot <NUM> can be further enhanced, and even if the vehicle intensively vibrates up and down and the like, the load or the impact can be absorbed.

In the above embodiment, the swinging fulcrum for adjusting the optical axis is provided at the lower left of the headlamp <NUM>; however, the swinging fulcrum may be provided at any position including a lower right or an upper right. Further, all of the swinging fulcrums may be used as the optical axis adjustment mechanism <NUM>, and instead of the swinging fulcrum, an optical axis adjustment unit may be provided, the optical axis adjustment unit being configured to perform an automatic adjustment in accordance with a posture of a vehicle.

Further, in the above embodiment, the holding member <NUM> that holds the light source <NUM> is the reflector; however, the holding member <NUM> is not limited to the reflector, and may be held by a member such as a bracket or a heat sink for heat radiation.

In addition, the bearing mechanism <NUM> including the pivot <NUM> and the case <NUM> may be applied not only to a product such as the optical axis adjustment mechanism <NUM> described above but also to an articulating portion of various types of machines requiring a spherical sliding bearing.

Claim 1:
A pivot (<NUM>), comprising:
a sphere unit (<NUM>) formed such that a through hole (<NUM>) capable of holding a shaft member (<NUM>) passes through a center of the sphere unit (<NUM>); and
a sliding guide unit (<NUM>) arranged to be suspended or mounted on a guide unit (<NUM>) of a lamp housing (<NUM>),
characterized in that:
the sphere unit (<NUM>) has two leg units (<NUM>) that connect the sphere unit (<NUM>) to the sliding guide unit (<NUM>),
the two legs (<NUM>) units are formed so as to overlap a plane (L) that is orthogonal to an axial direction of the through hole (<NUM>) and passes through the center, and to extend respectively from the left and right side surfaces of the sphere unit (<NUM>) to the sliding guide unit (<NUM>) as viewed from the front, so as to form as a space (S) an area surrounded by the sphere unit (<NUM>), the sliding guide unit (<NUM>), and the two leg units (<NUM>),
the sliding guide unit (<NUM>) includes a tabular plate (<NUM>) and an elastic piece (<NUM>), and the two leg units (<NUM>) are coupled to one surface of the plate (<NUM>) and the elastic piece (<NUM>) is coupled to the other surface of the plate; and
a surface of the sphere unit (<NUM>) surrounding the space (S) is a received surface to be borne in a vertical direction when mounted on the guide unit (<NUM>) of the lamp housing (<NUM>) when installed in a vehicle headlamp viewed from a front side on a lens side.