JP6534895B2 - Power transmission - Google Patents

Description

  The present invention relates to a power transmission device that operates various members using a rotation of a motor as a drive source.

  In an on-vehicle display device in which a movable panel on which a display screen is mounted is opened and closed by a power transmission device, components of the power transmission device including a motor are integrated in advance as a gear unit, and this gear unit is integrated into one A method of enhancing assembling workability by handling as parts is widely adopted.

  As a conventional example of this type of gear unit (power transmission device), each gear of the reduction gear train is rotatably supported by a bracket screwed to the motor, and a worm gear is attached as a drive gear to the rotation shaft of the motor. There is known one in which the motor, the reduction gear train and the bracket are assembled as one unit product by meshing the worm gear with the worm wheel which is the first gear of the reduction gear train (see Patent Document 1). ).

  In the power transmission device disclosed in Patent Document 1, a plate spring formed by bending an elastic piece is attached to the bracket, and pressing the elastic piece against the end of the worm gear causes the rotational shaft of the motor to rattle in the thrust direction. It is preventing it from sticking. Therefore, even when the direction of thrust force applied to the worm gear changes due to switching of the rotation direction of the motor, the dance of the rotation shaft associated therewith is suppressed by the spring force of the elastic piece, so the electric machine fixed to the rotation shaft of the motor It is possible to prevent the end of the armature (armature) from colliding with the bearing to generate noise.

Unexamined-Japanese-Patent No. 2006-14428

  In the above-described conventional power transmission device, the spring force of the elastic piece in contact with the tip of the worm gear is used to prevent backlash in the thrust direction of the rotating shaft, so the spring force of the elastic piece is not set relatively large. And, it will not be possible to suppress the dance of the rotating shaft with certainty. However, the greater the spring force of the elastic piece, the more noticeable the wear of the part in contact with the worm gear, and the repeated use creates a clearance between the elastic piece and the end of the worm gear, resulting in collision noise from the motor. There was a problem that occurs. Also, since the elastic piece bends every time the rotational direction of the motor changes, the pressure contact force of the elastic piece against the worm gear decreases over time, making it difficult to maintain the prevention of backlash in the thrust direction for a long period of time Met.

  The present invention has been made in view of the above-described circumstances of the prior art, and an object thereof is to provide a power transmission device capable of preventing rattling in the thrust direction of a rotating shaft of a motor for a long time.

In order to achieve the above object, a power transmission device according to the present invention comprises a motor, a drive gear attached to a rotation shaft of the motor, a driven gear meshing with the drive gear, the rotation shaft or the drive In a power transmission device including a gear as a rotating body, and a pressing mechanism configured to press one end of the rotating body to urge the rotating body in the axial direction, the pressing mechanism includes the one end of the rotating body. And a cam member provided with a cam surface which is rotatably disposed opposite to the rotation center, and the distance from the rotation center is sequentially different, and the cam member is rotationally biased in one direction to rotate the cam surface And an elastic member which is always in pressure contact directly or indirectly with one end of the cam, and the rotational biasing direction of the cam member is in pressure contact directly or indirectly with one end of the rotary body on the cam surface from the rotation center In the direction of increasing the distance to the point , It is characterized in that.

  In the power transmission device configured as described above, the cam surface is brought into pressure contact with one end portion of the rotating body directly or indirectly with respect to the cam member provided with the cam surface whose distances from the rotation center are sequentially different. Since the rotational force in the direction is always applied from the elastic member, there is no possibility that the pressure contact force between the cam surface and the rotating body is reduced by the external force, and the backlash in the thrust direction of the rotating body can be prevented for a long time it can. In addition, even when one end of the rotating body is worn, the cam member rotates in one direction following the amount of wear so that the distance from the rotation center of the cam member to the cam surface in contact with the receiving surface is increased. As a result, the pressure contact force between the cam surface and the rotating body is stably maintained over time, and from this point as well, it is possible to prevent the rotational direction of the rotating body from being worn in the thrust direction for a long period of time. it can.

  In the above configuration, a plate-like member is interposed between one end of the rotating body and the cam surface of the cam member, and the plate-like member is in contact with the cam surface of the cam member. It is preferable to have a lower receiving surface that abuts one end, because the pressing force from the cam member can be reliably transmitted to the rotating body.

  In this case, it is preferable to form a protrusion in contact with the cam surface on the upper receiving surface of the plate member, since the contact position between the cam surface and the plate member can be stabilized.

  Further, in the above configuration, when the rotation center of the cam member is positioned on an extension along the axis of the rotating body, the pressing force of the cam member can be efficiently transmitted to the rotating body, which is preferable.

  Further, in the above configuration, when the plate-like member is formed of a metal elastic plate and the side pressure piece resiliently contacting the outer periphery of the rotating body is bent on the metal elastic plate, the side pressure piece makes radial to the rotating body. Since the directional force is applied, it is possible to prevent not only the thrust direction of the rotating body but also the radial direction.

  Further, in the above configuration, the drive gear attached to the rotation shaft of the motor is not particularly limited. However, the drive gear is a worm gear, and a bracket for supporting the cam member is attached to the motor. If the worm wheel is pivotally supported by the bracket, a power transmission system having a large reduction ratio and a small backlash can be realized.

  In the power transmission device of the present invention, the rotational force in the direction of pressing the cam surface directly or indirectly against one end of the rotating body from the elastic member to the cam member is always applied, and one end of the rotating body is worn Even in this case, when the cam member rotates in one direction following the amount of wear, the cam member is displaced so as to increase the distance from the rotation center of the cam member to the cam surface in contact with the receiving surface. It is possible to prevent the rattling of the direction for a long time.

It is a perspective view of the power transmission device concerning the example of an embodiment of the present invention. It is a perspective view which removes and shows a bracket from this power transmission device. It is an exploded perspective view of the power transmission device. It is a side view which removes and shows a bracket from this power transmission device. It is operation | movement explanatory drawing of the cam member with which this power transmission device is equipped. It is explanatory drawing which shows the principal part of the power transmission device which concerns on the example of other embodiment of this invention.

  The embodiment of the invention will be described with reference to the drawings. As shown in FIGS. 1 to 4, the power transmission device according to the present embodiment is fixed to the motor 1 and the end face of the motor 1 using screws. The bracket 2, the support plate 3 fixed to the bracket 2 with a screw, the worm gear 4 as a drive gear attached to the rotation shaft 1a of the motor 1, and the worm wheel as a driven gear meshing with the worm gear 4 5 and a pressurizing mechanism 6 for urging the rotating shaft 1a of the motor 1 in the axial direction.

  The bracket 2 is formed by pressing a metal plate, and has a bottom plate portion 2a in which a through hole 7 is formed and a pair of upright portions 2b and 2c bent at a right angle from the bottom plate portion 2a. The rotating shaft 1a of the motor 1 and the worm gear 4 are inserted through the through hole 7 and reach between the two rising portions 2b and 2c, and these rising portions 2b and 2c face each other in parallel with the worm gear 4 interposed therebetween. A support shaft 8 is fixed to one of the rising portions 2b, and the worm wheel 5 and the gear 9 are coaxially supported by the support shaft 8. The worm wheel 5 and the gear 9 constitute a gear with a clutch, and a friction member (not shown) is interposed between the worm wheel 5 and the gear 9. In addition, another gear (not shown) engaged with the gear 9 is axially supported by the rising portion 2 b of the bracket 2, and a plurality of gears including the worm wheel 5 constitute a reduction gear train.

  The support plate 3 is integrated with the bracket 2 by screwing to the upright portion 2 b, and a support shaft 10 is fixed to the support plate 3. The support shaft 10 extends perpendicularly to a straight line (symbol P in FIG. 4) passing through the axis of the rotation shaft 1a, and the cam member 11 is rotatably supported by the support shaft 10. The cam member 11 has a cam surface 11a on a part of the circumferential surface, and the distance from the rotation center of the cam member 11 (the center of the support shaft 10) to the cam surface 11a is set to be sequentially different. On the paper surface of FIG. 4, the distance from the rotation center of the cam member 11 to the cam surface 11 a is such that the distance gradually and continuously increases along with the cam surface 11 a in the counterclockwise direction. It is set to. Further, a coil spring 12 is held between a protrusion 11 a provided on the outer edge of the cam member 11 and the upper end of the support plate 3. It is rotationally biased in one direction (clockwise in FIG. 4) in the center. The cam mechanism 11 and the coil spring 12 constitute the pressurizing mechanism 6 described above.

  A metal elastic plate 13 is fixed to the other standing portion 2c of the bracket 2 using a screw, and a plate-like piece 13a and a side pressure piece 13b are bent and formed on the metal elastic plate 13. The plate-like piece 13a extends horizontally in a plane orthogonal to a straight line P passing through the axis of the rotation shaft 1a, and this plate-like piece 13a is inserted between the upper end of the worm gear 4 and the cam surface 11a of the cam member 11. It is done. Here, when the portion of the plate-like piece 13a in contact with the cam surface 11a is referred to as the upper receiving surface, the distance from the center of rotation to the cam surface 11a contacting the upper receiving surface is increased by the coil spring 12 described above. It is biased in the direction. When the portion of the plate-like piece 13a in contact with the upper end of the worm gear 4 is referred to as the lower receiving surface, the lower receiving surface of the plate-like piece 13a is formed on the upper end of the worm gear 4 opposite the upper receiving surface. It is in contact with the spherical projection 4a. On the other hand, the side pressure pieces 13b extend along a plane parallel to a straight line P passing through the axis of the rotary shaft 1a, and the side pressure pieces 13b are pressed against the outer surface of the upper end portion of the worm gear 4 by its own elasticity.

  The power transmission device configured in this way is used, for example, as a movable mechanism for opening and closing the movable panel provided in the in-vehicle display device, and the rotation of the motor 1 is transmitted from the worm gear 4 through the reduction gear train including the worm wheel 5. By being transmitted to the movable panel, the movable panel is exposed / stored from the housing in accordance with the rotation direction of the motor 1.

  A plate-like piece 13 a is interposed between the upper end of the worm gear 4 attached to the rotation shaft 1 a of the motor 1 and the cam surface 11 a of the cam member 11. Since the pressing force of the cam member 11 being transmitted is transmitted to the upper end of the worm gear 4 via the plate-like piece 13a, the pressing force (contact force) is received and the thrust direction (axial direction) of the worm gear 4 and the rotary shaft 1a The rattling of) is prevented. Therefore, even when the rotation direction of the motor 1 is switched and the direction of the thrust force applied to the worm gear 4 is changed, the dance of the rotation shaft 1a accompanying it is suppressed by the pressurizing mechanism 6, so generation of noise from the motor 1 Can be prevented. Further, since the side pressure piece 13b is in pressure contact with the outer periphery of the upper end portion of the worm gear 4, the worm gear 4 and the rotary shaft 1a are prevented not only in the thrust direction but also in the radial direction.

  Here, in the initial state of use of the power transmission device, as shown in FIG. 5A, the protrusion 4a of the worm gear 4 in contact with the lower receiving surface of the plate-like piece 13a is not worn, and the cam member 11 The distance from the center of rotation of the cam to the cam surface 11a in contact with the upper receiving surface Q of the plate-like piece 13a is minimized. In addition, when the power transmission device is used for a long time, the protrusion 4a of the worm gear 4 gradually wears, but as shown in FIG. 5 (b), the cam member 11 follows the amount of wear of the protrusion 4a. In order to rotate in the clockwise direction in the drawing, the cam member 11 is displaced so as to increase the distance from the rotation center of the cam member 11 to the cam surface 11 a in contact with the upper receiving surface Q. Therefore, a stable pressing force is applied to the worm gear 4 from the cam member 11 regardless of the amount of wear of the protrusion 4a, and the rattling of the worm gear 4 and the rotary shaft 1a in the thrust direction is prevented for a long time. Can.

  As described above, in the power transmission device according to the present embodiment, the cam member 11 provided with the cam surface 11a whose distance from the rotation center (the support shaft 10) is sequentially different is an elastic member. Since the rotational force in the direction of pressing the cam surface 11a from the coil spring 12 to the projection 4a of the worm gear 4 is always applied, it is possible to prevent rattling of the worm gear 4 and the rotational shaft 1a in the thrust direction. Further, even if the protrusion 4a of the worm gear 4 wears due to long-term use, the cam surface coming in contact with the receiving surface from the rotation center of the cam member 11 by the cam member 11 rotating in one direction following the amount of wear. Since the distance to 11a is displaced to a large extent, the pressing force of the cam surface 11a against the projection 4a of the worm gear 4 is stably maintained over time, and the rattle of the worm gear 4 and the rotary shaft 1a in the thrust direction is prolonged. It can be prevented over.

  Further, a plate-like piece 13a which is a plate-like member is interposed between the projection 4a of the worm gear 4 and the cam member 11, and the cam surface 11a of the cam member 11 is on the upper receiving surface of the plate-like piece 13a. Since the lower receiving surface of the plate-like piece 13 a is in contact with the projection 4 a of the worm gear 4 while being in contact with it, the pressing force of the cam member 11 can be reliably transmitted in the axial direction of the worm gear 4. Moreover, since the rotation center of the cam member 11 is set on the extension line P along the axis of the rotation shaft 1a, the pressing force of the cam member 11 can be efficiently transmitted in the axial direction of the rotation shaft 1a.

  Further, not only the plate-like piece 13a but also the side pressure piece 13b is bent and formed on the metal elastic plate 13, and by making the side pressure piece 13b elastically contact the outer periphery of the upper end portion of the worm gear 4, the side pressure piece 13b to the worm gear 4 On the other hand, since a force in the radial direction is applied, it is possible to prevent not only rattling of the worm gear 4 and the rotary shaft 1a in the thrust direction but also rattling of the radial direction.

  In the above embodiment, the cam surface 11a of the cam member 11 is in pressure contact with the flat upper receiving surface of the plate-like piece 13a. However, as shown in FIG. 6, the projection on the upper receiving surface of the plate-like piece 13a 13c may be formed, and the cam surface 11a may be brought into pressure contact with the projection 13c, whereby the contact position between the cam surface 11a and the plate-like piece 13a can be stabilized. In this case, since the lower surface of the plate-like piece 13a is not flat by forming the protrusion 13c, the position of the protrusion 13c is slightly shifted with respect to a straight line P along the axis of the rotary shaft 1a, and the plate-like piece 13a is flat. It is preferable that the lower receiving surface be in pressure contact with the projection 4 a of the worm gear 4. However, if the projection 13c is retrofitted on the plate-like piece 13a using a means such as welding, the flat lower receiving surface of the plate-like piece 13a can be positioned while the projection 13c is positioned on the axis of the rotary shaft 1a. Can be pressed into contact with the projections 4 a of the worm gear 4.

  Further, in the embodiment described above, the biasing force of the pressurizing mechanism 6 constituted by the cam member 11 and the coil spring 12 is transmitted to the projection 4 a of the worm gear 4 through the plate-like piece 13 a. However, the plate-like piece 13a is omitted so that the cam surface 11a of the cam member 11 is brought into direct pressure contact with the projection 4a of the worm gear 4, or another elastic member such as a plate spring or elastic rubber is used instead of the coil spring 12. You may

  In the above embodiment, the worm gear 4 having the projection 4a on the tip end is press-fit and fixed to the rotary shaft 1a of the motor 1, and the pressing force of the cam member 11 is a protrusion of the worm gear 4 via the plate-like piece 13a. The pressing force of the cam member 11 is transmitted through the plate-like piece 13a by causing the rotary shaft 1a of the motor 1 to project from the end of the worm gear 4 though the rotary shaft 1a of the motor 1 is transmitted to the portion 4a. It may be transmitted to the tip of the Further, the gear attached to the rotation shaft 1a of the motor 1 is not limited to the worm gear 4, and it is also possible to use other gears such as helical gears and bevel gears.

Reference Signs List 1 motor 1a rotation shaft 2 bracket 2a bottom plate portion 2b, 2c rising portion 3 support plate 4 worm gear (drive gear)
5 Worm wheel (follower gear)
6 pressurizing mechanism 7 through hole 8 support shaft 9 gear 10 support shaft 11 cam member 11a cam surface 12 coil spring (elastic member)
13 Metal elastic plate 13a Plate-like piece 13b Side pressure piece 13c Protrusion

Claims (6)

A motor, a drive gear attached to a rotation shaft of the motor, a driven gear meshing with the drive gear, the rotation shaft or the drive gear as a rotating body, and pressing one end of the rotating body And a pressure transmission mechanism for urging the rotating body in the axial direction.
The pressure applying mechanism is rotatably disposed opposite to one end of the rotating body, and provided with a cam member provided with a cam surface whose distance from the rotation center is sequentially different, and the cam member in one direction And an elastic member for constantly urging the cam surface directly or indirectly against one end of the rotating body .
The rotational biasing direction of the cam member is a direction in which the distance from the center of rotation to a portion of the cam surface, which is in direct or indirect pressure contact with one end of the rotating body, increases.
Power transmission device characterized by   In the first aspect of the present invention, a plate-like member is interposed between one end of the rotating body and the cam surface of the cam member, and the plate-like member is in contact with the upper surface. And a lower receiving surface that abuts on one end of the rotating body.   The power transmission device according to claim 2, wherein a protrusion in contact with the cam surface is formed on the upper receiving surface of the plate-like member.   The power transmission device according to claim 2, wherein the rotation center of the cam member is located on an extension along the axis of the rotating body.   In the description of any one of claims 2 to 4, it is preferable that the plate-like member is made of a metal elastic plate, and a side pressure piece resiliently contacting the outer peripheral surface of the rotating body is bent on the metal elastic plate. Characteristic power transmission device.   The bracket according to any one of claims 1 to 5, wherein a bracket for supporting the cam member is attached to the motor, the drive gear is a worm gear, and the driven gear is pivotally supported by the bracket. A power transmission device characterized in that it is a worm wheel.